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 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2602 * resend 2603 */ 2604 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2605 SCTP_TRANSPORT(asoc->peer.primary_path)); 2606 2607 /* Cast away the const modifier, as we want to just 2608 * rerun it through as a sideffect. 2609 */ 2610 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2611 2612 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2613 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2614 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2615 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2616 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2617 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2618 2619 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2620 2621 return SCTP_DISPOSITION_CONSUME; 2622 2623 nomem: 2624 return SCTP_DISPOSITION_NOMEM; 2625 } 2626 2627 /* 2628 * Process an ABORT. 2629 * 2630 * Section: 9.1 2631 * After checking the Verification Tag, the receiving endpoint shall 2632 * remove the association from its record, and shall report the 2633 * termination to its upper layer. 2634 * 2635 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2636 * B) Rules for packet carrying ABORT: 2637 * 2638 * - The endpoint shall always fill in the Verification Tag field of the 2639 * outbound packet with the destination endpoint's tag value if it 2640 * is known. 2641 * 2642 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2643 * MUST follow the procedure described in Section 8.4. 2644 * 2645 * - The receiver MUST accept the packet if the Verification Tag 2646 * matches either its own tag, OR the tag of its peer. Otherwise, the 2647 * receiver MUST silently discard the packet and take no further 2648 * action. 2649 * 2650 * Inputs 2651 * (endpoint, asoc, chunk) 2652 * 2653 * Outputs 2654 * (asoc, reply_msg, msg_up, timers, counters) 2655 * 2656 * The return value is the disposition of the chunk. 2657 */ 2658 enum sctp_disposition sctp_sf_do_9_1_abort( 2659 struct net *net, 2660 const struct sctp_endpoint *ep, 2661 const struct sctp_association *asoc, 2662 const union sctp_subtype type, 2663 void *arg, 2664 struct sctp_cmd_seq *commands) 2665 { 2666 struct sctp_chunk *chunk = arg; 2667 2668 if (!sctp_vtag_verify_either(chunk, asoc)) 2669 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2670 2671 /* Make sure that the ABORT chunk has a valid length. 2672 * Since this is an ABORT chunk, we have to discard it 2673 * because of the following text: 2674 * RFC 2960, Section 3.3.7 2675 * If an endpoint receives an ABORT with a format error or for an 2676 * association that doesn't exist, it MUST silently discard it. 2677 * Because the length is "invalid", we can't really discard just 2678 * as we do not know its true length. So, to be safe, discard the 2679 * packet. 2680 */ 2681 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2682 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2683 2684 /* ADD-IP: Special case for ABORT chunks 2685 * F4) One special consideration is that ABORT Chunks arriving 2686 * destined to the IP address being deleted MUST be 2687 * ignored (see Section 5.3.1 for further details). 2688 */ 2689 if (SCTP_ADDR_DEL == 2690 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2691 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2692 2693 if (!sctp_err_chunk_valid(chunk)) 2694 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2695 2696 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2697 } 2698 2699 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2700 struct net *net, 2701 const struct sctp_endpoint *ep, 2702 const struct sctp_association *asoc, 2703 const union sctp_subtype type, 2704 void *arg, 2705 struct sctp_cmd_seq *commands) 2706 { 2707 __be16 error = SCTP_ERROR_NO_ERROR; 2708 struct sctp_chunk *chunk = arg; 2709 unsigned int len; 2710 2711 /* See if we have an error cause code in the chunk. */ 2712 len = ntohs(chunk->chunk_hdr->length); 2713 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2714 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2715 2716 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2717 /* ASSOC_FAILED will DELETE_TCB. */ 2718 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2719 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2720 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2721 2722 return SCTP_DISPOSITION_ABORT; 2723 } 2724 2725 /* 2726 * Process an ABORT. (COOKIE-WAIT state) 2727 * 2728 * See sctp_sf_do_9_1_abort() above. 2729 */ 2730 enum sctp_disposition sctp_sf_cookie_wait_abort( 2731 struct net *net, 2732 const struct sctp_endpoint *ep, 2733 const struct sctp_association *asoc, 2734 const union sctp_subtype type, 2735 void *arg, 2736 struct sctp_cmd_seq *commands) 2737 { 2738 __be16 error = SCTP_ERROR_NO_ERROR; 2739 struct sctp_chunk *chunk = arg; 2740 unsigned int len; 2741 2742 if (!sctp_vtag_verify_either(chunk, asoc)) 2743 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2744 2745 /* Make sure that the ABORT chunk has a valid length. 2746 * Since this is an ABORT chunk, we have to discard it 2747 * because of the following text: 2748 * RFC 2960, Section 3.3.7 2749 * If an endpoint receives an ABORT with a format error or for an 2750 * association that doesn't exist, it MUST silently discard it. 2751 * Because the length is "invalid", we can't really discard just 2752 * as we do not know its true length. So, to be safe, discard the 2753 * packet. 2754 */ 2755 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2756 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2757 2758 /* See if we have an error cause code in the chunk. */ 2759 len = ntohs(chunk->chunk_hdr->length); 2760 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2761 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2762 2763 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2764 chunk->transport); 2765 } 2766 2767 /* 2768 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2769 */ 2770 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2771 struct net *net, 2772 const struct sctp_endpoint *ep, 2773 const struct sctp_association *asoc, 2774 const union sctp_subtype type, 2775 void *arg, 2776 struct sctp_cmd_seq *commands) 2777 { 2778 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2779 ENOPROTOOPT, asoc, 2780 (struct sctp_transport *)arg); 2781 } 2782 2783 /* 2784 * Process an ABORT. (COOKIE-ECHOED state) 2785 */ 2786 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2787 struct net *net, 2788 const struct sctp_endpoint *ep, 2789 const struct sctp_association *asoc, 2790 const union sctp_subtype type, 2791 void *arg, 2792 struct sctp_cmd_seq *commands) 2793 { 2794 /* There is a single T1 timer, so we should be able to use 2795 * common function with the COOKIE-WAIT state. 2796 */ 2797 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2798 } 2799 2800 /* 2801 * Stop T1 timer and abort association with "INIT failed". 2802 * 2803 * This is common code called by several sctp_sf_*_abort() functions above. 2804 */ 2805 static enum sctp_disposition sctp_stop_t1_and_abort( 2806 struct net *net, 2807 struct sctp_cmd_seq *commands, 2808 __be16 error, int sk_err, 2809 const struct sctp_association *asoc, 2810 struct sctp_transport *transport) 2811 { 2812 pr_debug("%s: ABORT received (INIT)\n", __func__); 2813 2814 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2815 SCTP_STATE(SCTP_STATE_CLOSED)); 2816 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2817 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2818 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2819 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2820 /* CMD_INIT_FAILED will DELETE_TCB. */ 2821 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2822 SCTP_PERR(error)); 2823 2824 return SCTP_DISPOSITION_ABORT; 2825 } 2826 2827 /* 2828 * sctp_sf_do_9_2_shut 2829 * 2830 * Section: 9.2 2831 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2832 * - enter the SHUTDOWN-RECEIVED state, 2833 * 2834 * - stop accepting new data from its SCTP user 2835 * 2836 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2837 * that all its outstanding DATA chunks have been received by the 2838 * SHUTDOWN sender. 2839 * 2840 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2841 * send a SHUTDOWN in response to a ULP request. And should discard 2842 * subsequent SHUTDOWN chunks. 2843 * 2844 * If there are still outstanding DATA chunks left, the SHUTDOWN 2845 * receiver shall continue to follow normal data transmission 2846 * procedures defined in Section 6 until all outstanding DATA chunks 2847 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2848 * new data from its SCTP user. 2849 * 2850 * Verification Tag: 8.5 Verification Tag [Normal verification] 2851 * 2852 * Inputs 2853 * (endpoint, asoc, chunk) 2854 * 2855 * Outputs 2856 * (asoc, reply_msg, msg_up, timers, counters) 2857 * 2858 * The return value is the disposition of the chunk. 2859 */ 2860 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2861 struct net *net, 2862 const struct sctp_endpoint *ep, 2863 const struct sctp_association *asoc, 2864 const union sctp_subtype type, 2865 void *arg, 2866 struct sctp_cmd_seq *commands) 2867 { 2868 enum sctp_disposition disposition; 2869 struct sctp_chunk *chunk = arg; 2870 struct sctp_shutdownhdr *sdh; 2871 struct sctp_ulpevent *ev; 2872 __u32 ctsn; 2873 2874 if (!sctp_vtag_verify(chunk, asoc)) 2875 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2876 2877 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2878 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2879 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2880 commands); 2881 2882 /* Convert the elaborate header. */ 2883 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2884 skb_pull(chunk->skb, sizeof(*sdh)); 2885 chunk->subh.shutdown_hdr = sdh; 2886 ctsn = ntohl(sdh->cum_tsn_ack); 2887 2888 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2889 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2890 asoc->ctsn_ack_point); 2891 2892 return SCTP_DISPOSITION_DISCARD; 2893 } 2894 2895 /* If Cumulative TSN Ack beyond the max tsn currently 2896 * send, terminating the association and respond to the 2897 * sender with an ABORT. 2898 */ 2899 if (!TSN_lt(ctsn, asoc->next_tsn)) 2900 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2901 2902 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2903 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2904 * inform the application that it should cease sending data. 2905 */ 2906 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2907 if (!ev) { 2908 disposition = SCTP_DISPOSITION_NOMEM; 2909 goto out; 2910 } 2911 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2912 2913 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2914 * - enter the SHUTDOWN-RECEIVED state, 2915 * - stop accepting new data from its SCTP user 2916 * 2917 * [This is implicit in the new state.] 2918 */ 2919 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2920 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2921 disposition = SCTP_DISPOSITION_CONSUME; 2922 2923 if (sctp_outq_is_empty(&asoc->outqueue)) { 2924 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2925 arg, commands); 2926 } 2927 2928 if (SCTP_DISPOSITION_NOMEM == disposition) 2929 goto out; 2930 2931 /* - verify, by checking the Cumulative TSN Ack field of the 2932 * chunk, that all its outstanding DATA chunks have been 2933 * received by the SHUTDOWN sender. 2934 */ 2935 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2936 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2937 2938 out: 2939 return disposition; 2940 } 2941 2942 /* 2943 * sctp_sf_do_9_2_shut_ctsn 2944 * 2945 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2946 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2947 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2948 * MUST be processed. 2949 */ 2950 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2951 struct net *net, 2952 const struct sctp_endpoint *ep, 2953 const struct sctp_association *asoc, 2954 const union sctp_subtype type, 2955 void *arg, 2956 struct sctp_cmd_seq *commands) 2957 { 2958 struct sctp_chunk *chunk = arg; 2959 struct sctp_shutdownhdr *sdh; 2960 __u32 ctsn; 2961 2962 if (!sctp_vtag_verify(chunk, asoc)) 2963 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2964 2965 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2966 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2967 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2968 commands); 2969 2970 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2971 ctsn = ntohl(sdh->cum_tsn_ack); 2972 2973 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2974 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2975 asoc->ctsn_ack_point); 2976 2977 return SCTP_DISPOSITION_DISCARD; 2978 } 2979 2980 /* If Cumulative TSN Ack beyond the max tsn currently 2981 * send, terminating the association and respond to the 2982 * sender with an ABORT. 2983 */ 2984 if (!TSN_lt(ctsn, asoc->next_tsn)) 2985 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2986 2987 /* verify, by checking the Cumulative TSN Ack field of the 2988 * chunk, that all its outstanding DATA chunks have been 2989 * received by the SHUTDOWN sender. 2990 */ 2991 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2992 SCTP_BE32(sdh->cum_tsn_ack)); 2993 2994 return SCTP_DISPOSITION_CONSUME; 2995 } 2996 2997 /* RFC 2960 9.2 2998 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2999 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 3000 * transport addresses (either in the IP addresses or in the INIT chunk) 3001 * that belong to this association, it should discard the INIT chunk and 3002 * retransmit the SHUTDOWN ACK chunk. 3003 */ 3004 static enum sctp_disposition 3005 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3006 const struct sctp_association *asoc, 3007 const union sctp_subtype type, void *arg, 3008 struct sctp_cmd_seq *commands) 3009 { 3010 struct sctp_chunk *chunk = arg; 3011 struct sctp_chunk *reply; 3012 3013 /* Make sure that the chunk has a valid length */ 3014 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3015 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3016 commands); 3017 3018 /* Since we are not going to really process this INIT, there 3019 * is no point in verifying chunk boundaries. Just generate 3020 * the SHUTDOWN ACK. 3021 */ 3022 reply = sctp_make_shutdown_ack(asoc, chunk); 3023 if (NULL == reply) 3024 goto nomem; 3025 3026 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 3027 * the T2-SHUTDOWN timer. 3028 */ 3029 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 3030 3031 /* and restart the T2-shutdown timer. */ 3032 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3033 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3034 3035 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3036 3037 return SCTP_DISPOSITION_CONSUME; 3038 nomem: 3039 return SCTP_DISPOSITION_NOMEM; 3040 } 3041 3042 enum sctp_disposition 3043 sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3044 const struct sctp_association *asoc, 3045 const union sctp_subtype type, void *arg, 3046 struct sctp_cmd_seq *commands) 3047 { 3048 struct sctp_chunk *chunk = arg; 3049 3050 if (!chunk->singleton) 3051 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3052 3053 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 3054 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3055 3056 if (chunk->sctp_hdr->vtag != 0) 3057 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3058 3059 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands); 3060 } 3061 3062 /* 3063 * sctp_sf_do_ecn_cwr 3064 * 3065 * Section: Appendix A: Explicit Congestion Notification 3066 * 3067 * CWR: 3068 * 3069 * RFC 2481 details a specific bit for a sender to send in the header of 3070 * its next outbound TCP segment to indicate to its peer that it has 3071 * reduced its congestion window. This is termed the CWR bit. For 3072 * SCTP the same indication is made by including the CWR chunk. 3073 * This chunk contains one data element, i.e. the TSN number that 3074 * was sent in the ECNE chunk. This element represents the lowest 3075 * TSN number in the datagram that was originally marked with the 3076 * CE bit. 3077 * 3078 * Verification Tag: 8.5 Verification Tag [Normal verification] 3079 * Inputs 3080 * (endpoint, asoc, chunk) 3081 * 3082 * Outputs 3083 * (asoc, reply_msg, msg_up, timers, counters) 3084 * 3085 * The return value is the disposition of the chunk. 3086 */ 3087 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3088 const struct sctp_endpoint *ep, 3089 const struct sctp_association *asoc, 3090 const union sctp_subtype type, 3091 void *arg, 3092 struct sctp_cmd_seq *commands) 3093 { 3094 struct sctp_chunk *chunk = arg; 3095 struct sctp_cwrhdr *cwr; 3096 u32 lowest_tsn; 3097 3098 if (!sctp_vtag_verify(chunk, asoc)) 3099 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3100 3101 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3102 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3103 commands); 3104 3105 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3106 skb_pull(chunk->skb, sizeof(*cwr)); 3107 3108 lowest_tsn = ntohl(cwr->lowest_tsn); 3109 3110 /* Does this CWR ack the last sent congestion notification? */ 3111 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3112 /* Stop sending ECNE. */ 3113 sctp_add_cmd_sf(commands, 3114 SCTP_CMD_ECN_CWR, 3115 SCTP_U32(lowest_tsn)); 3116 } 3117 return SCTP_DISPOSITION_CONSUME; 3118 } 3119 3120 /* 3121 * sctp_sf_do_ecne 3122 * 3123 * Section: Appendix A: Explicit Congestion Notification 3124 * 3125 * ECN-Echo 3126 * 3127 * RFC 2481 details a specific bit for a receiver to send back in its 3128 * TCP acknowledgements to notify the sender of the Congestion 3129 * Experienced (CE) bit having arrived from the network. For SCTP this 3130 * same indication is made by including the ECNE chunk. This chunk 3131 * contains one data element, i.e. the lowest TSN associated with the IP 3132 * datagram marked with the CE bit..... 3133 * 3134 * Verification Tag: 8.5 Verification Tag [Normal verification] 3135 * Inputs 3136 * (endpoint, asoc, chunk) 3137 * 3138 * Outputs 3139 * (asoc, reply_msg, msg_up, timers, counters) 3140 * 3141 * The return value is the disposition of the chunk. 3142 */ 3143 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3144 const struct sctp_endpoint *ep, 3145 const struct sctp_association *asoc, 3146 const union sctp_subtype type, 3147 void *arg, struct sctp_cmd_seq *commands) 3148 { 3149 struct sctp_chunk *chunk = arg; 3150 struct sctp_ecnehdr *ecne; 3151 3152 if (!sctp_vtag_verify(chunk, asoc)) 3153 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3154 3155 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3156 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3157 commands); 3158 3159 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3160 skb_pull(chunk->skb, sizeof(*ecne)); 3161 3162 /* If this is a newer ECNE than the last CWR packet we sent out */ 3163 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3164 SCTP_U32(ntohl(ecne->lowest_tsn))); 3165 3166 return SCTP_DISPOSITION_CONSUME; 3167 } 3168 3169 /* 3170 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3171 * 3172 * The SCTP endpoint MUST always acknowledge the reception of each valid 3173 * DATA chunk. 3174 * 3175 * The guidelines on delayed acknowledgement algorithm specified in 3176 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3177 * acknowledgement SHOULD be generated for at least every second packet 3178 * (not every second DATA chunk) received, and SHOULD be generated within 3179 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3180 * situations it may be beneficial for an SCTP transmitter to be more 3181 * conservative than the algorithms detailed in this document allow. 3182 * However, an SCTP transmitter MUST NOT be more aggressive than the 3183 * following algorithms allow. 3184 * 3185 * A SCTP receiver MUST NOT generate more than one SACK for every 3186 * incoming packet, other than to update the offered window as the 3187 * receiving application consumes new data. 3188 * 3189 * Verification Tag: 8.5 Verification Tag [Normal verification] 3190 * 3191 * Inputs 3192 * (endpoint, asoc, chunk) 3193 * 3194 * Outputs 3195 * (asoc, reply_msg, msg_up, timers, counters) 3196 * 3197 * The return value is the disposition of the chunk. 3198 */ 3199 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3200 const struct sctp_endpoint *ep, 3201 const struct sctp_association *asoc, 3202 const union sctp_subtype type, 3203 void *arg, 3204 struct sctp_cmd_seq *commands) 3205 { 3206 union sctp_arg force = SCTP_NOFORCE(); 3207 struct sctp_chunk *chunk = arg; 3208 int error; 3209 3210 if (!sctp_vtag_verify(chunk, asoc)) { 3211 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3212 SCTP_NULL()); 3213 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3214 } 3215 3216 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3217 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3218 commands); 3219 3220 error = sctp_eat_data(asoc, chunk, commands); 3221 switch (error) { 3222 case SCTP_IERROR_NO_ERROR: 3223 break; 3224 case SCTP_IERROR_HIGH_TSN: 3225 case SCTP_IERROR_BAD_STREAM: 3226 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3227 goto discard_noforce; 3228 case SCTP_IERROR_DUP_TSN: 3229 case SCTP_IERROR_IGNORE_TSN: 3230 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3231 goto discard_force; 3232 case SCTP_IERROR_NO_DATA: 3233 return SCTP_DISPOSITION_ABORT; 3234 case SCTP_IERROR_PROTO_VIOLATION: 3235 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3236 (u8 *)chunk->subh.data_hdr, 3237 sctp_datahdr_len(&asoc->stream)); 3238 default: 3239 BUG(); 3240 } 3241 3242 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3243 force = SCTP_FORCE(); 3244 3245 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3246 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3247 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3248 } 3249 3250 /* If this is the last chunk in a packet, we need to count it 3251 * toward sack generation. Note that we need to SACK every 3252 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3253 * THEM. We elect to NOT generate SACK's if the chunk fails 3254 * the verification tag test. 3255 * 3256 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3257 * 3258 * The SCTP endpoint MUST always acknowledge the reception of 3259 * each valid DATA chunk. 3260 * 3261 * The guidelines on delayed acknowledgement algorithm 3262 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3263 * Specifically, an acknowledgement SHOULD be generated for at 3264 * least every second packet (not every second DATA chunk) 3265 * received, and SHOULD be generated within 200 ms of the 3266 * arrival of any unacknowledged DATA chunk. In some 3267 * situations it may be beneficial for an SCTP transmitter to 3268 * be more conservative than the algorithms detailed in this 3269 * document allow. However, an SCTP transmitter MUST NOT be 3270 * more aggressive than the following algorithms allow. 3271 */ 3272 if (chunk->end_of_packet) 3273 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3274 3275 return SCTP_DISPOSITION_CONSUME; 3276 3277 discard_force: 3278 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3279 * 3280 * When a packet arrives with duplicate DATA chunk(s) and with 3281 * no new DATA chunk(s), the endpoint MUST immediately send a 3282 * SACK with no delay. If a packet arrives with duplicate 3283 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3284 * MAY immediately send a SACK. Normally receipt of duplicate 3285 * DATA chunks will occur when the original SACK chunk was lost 3286 * and the peer's RTO has expired. The duplicate TSN number(s) 3287 * SHOULD be reported in the SACK as duplicate. 3288 */ 3289 /* In our case, we split the MAY SACK advice up whether or not 3290 * the last chunk is a duplicate.' 3291 */ 3292 if (chunk->end_of_packet) 3293 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3294 return SCTP_DISPOSITION_DISCARD; 3295 3296 discard_noforce: 3297 if (chunk->end_of_packet) 3298 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3299 3300 return SCTP_DISPOSITION_DISCARD; 3301 } 3302 3303 /* 3304 * sctp_sf_eat_data_fast_4_4 3305 * 3306 * Section: 4 (4) 3307 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3308 * DATA chunks without delay. 3309 * 3310 * Verification Tag: 8.5 Verification Tag [Normal verification] 3311 * Inputs 3312 * (endpoint, asoc, chunk) 3313 * 3314 * Outputs 3315 * (asoc, reply_msg, msg_up, timers, counters) 3316 * 3317 * The return value is the disposition of the chunk. 3318 */ 3319 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3320 struct net *net, 3321 const struct sctp_endpoint *ep, 3322 const struct sctp_association *asoc, 3323 const union sctp_subtype type, 3324 void *arg, 3325 struct sctp_cmd_seq *commands) 3326 { 3327 struct sctp_chunk *chunk = arg; 3328 int error; 3329 3330 if (!sctp_vtag_verify(chunk, asoc)) { 3331 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3332 SCTP_NULL()); 3333 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3334 } 3335 3336 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3337 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3338 commands); 3339 3340 error = sctp_eat_data(asoc, chunk, commands); 3341 switch (error) { 3342 case SCTP_IERROR_NO_ERROR: 3343 case SCTP_IERROR_HIGH_TSN: 3344 case SCTP_IERROR_DUP_TSN: 3345 case SCTP_IERROR_IGNORE_TSN: 3346 case SCTP_IERROR_BAD_STREAM: 3347 break; 3348 case SCTP_IERROR_NO_DATA: 3349 return SCTP_DISPOSITION_ABORT; 3350 case SCTP_IERROR_PROTO_VIOLATION: 3351 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3352 (u8 *)chunk->subh.data_hdr, 3353 sctp_datahdr_len(&asoc->stream)); 3354 default: 3355 BUG(); 3356 } 3357 3358 /* Go a head and force a SACK, since we are shutting down. */ 3359 3360 /* Implementor's Guide. 3361 * 3362 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3363 * respond to each received packet containing one or more DATA chunk(s) 3364 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3365 */ 3366 if (chunk->end_of_packet) { 3367 /* We must delay the chunk creation since the cumulative 3368 * TSN has not been updated yet. 3369 */ 3370 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3371 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3372 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3373 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3374 } 3375 3376 return SCTP_DISPOSITION_CONSUME; 3377 } 3378 3379 /* 3380 * Section: 6.2 Processing a Received SACK 3381 * D) Any time a SACK arrives, the endpoint performs the following: 3382 * 3383 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3384 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3385 * increasing, a SACK whose Cumulative TSN Ack is less than the 3386 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3387 * 3388 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3389 * of bytes still outstanding after processing the Cumulative TSN Ack 3390 * and the Gap Ack Blocks. 3391 * 3392 * iii) If the SACK is missing a TSN that was previously 3393 * acknowledged via a Gap Ack Block (e.g., the data receiver 3394 * reneged on the data), then mark the corresponding DATA chunk 3395 * as available for retransmit: Mark it as missing for fast 3396 * retransmit as described in Section 7.2.4 and if no retransmit 3397 * timer is running for the destination address to which the DATA 3398 * chunk was originally transmitted, then T3-rtx is started for 3399 * that destination address. 3400 * 3401 * Verification Tag: 8.5 Verification Tag [Normal verification] 3402 * 3403 * Inputs 3404 * (endpoint, asoc, chunk) 3405 * 3406 * Outputs 3407 * (asoc, reply_msg, msg_up, timers, counters) 3408 * 3409 * The return value is the disposition of the chunk. 3410 */ 3411 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3412 const struct sctp_endpoint *ep, 3413 const struct sctp_association *asoc, 3414 const union sctp_subtype type, 3415 void *arg, 3416 struct sctp_cmd_seq *commands) 3417 { 3418 struct sctp_chunk *chunk = arg; 3419 struct sctp_sackhdr *sackh; 3420 __u32 ctsn; 3421 3422 if (!sctp_vtag_verify(chunk, asoc)) 3423 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3424 3425 /* Make sure that the SACK chunk has a valid length. */ 3426 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3427 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3428 commands); 3429 3430 /* Pull the SACK chunk from the data buffer */ 3431 sackh = sctp_sm_pull_sack(chunk); 3432 /* Was this a bogus SACK? */ 3433 if (!sackh) 3434 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3435 chunk->subh.sack_hdr = sackh; 3436 ctsn = ntohl(sackh->cum_tsn_ack); 3437 3438 /* If Cumulative TSN Ack beyond the max tsn currently 3439 * send, terminating the association and respond to the 3440 * sender with an ABORT. 3441 */ 3442 if (TSN_lte(asoc->next_tsn, ctsn)) 3443 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3444 3445 trace_sctp_probe(ep, asoc, chunk); 3446 3447 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3448 * Ack Point, then drop the SACK. Since Cumulative TSN 3449 * Ack is monotonically increasing, a SACK whose 3450 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3451 * Point indicates an out-of-order SACK. 3452 */ 3453 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3454 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3455 asoc->ctsn_ack_point); 3456 3457 return SCTP_DISPOSITION_DISCARD; 3458 } 3459 3460 /* Return this SACK for further processing. */ 3461 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3462 3463 /* Note: We do the rest of the work on the PROCESS_SACK 3464 * sideeffect. 3465 */ 3466 return SCTP_DISPOSITION_CONSUME; 3467 } 3468 3469 /* 3470 * Generate an ABORT in response to a packet. 3471 * 3472 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3473 * 3474 * 8) The receiver should respond to the sender of the OOTB packet with 3475 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3476 * MUST fill in the Verification Tag field of the outbound packet 3477 * with the value found in the Verification Tag field of the OOTB 3478 * packet and set the T-bit in the Chunk Flags to indicate that the 3479 * Verification Tag is reflected. After sending this ABORT, the 3480 * receiver of the OOTB packet shall discard the OOTB packet and take 3481 * no further action. 3482 * 3483 * Verification Tag: 3484 * 3485 * The return value is the disposition of the chunk. 3486 */ 3487 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3488 struct net *net, 3489 const struct sctp_endpoint *ep, 3490 const struct sctp_association *asoc, 3491 const union sctp_subtype type, 3492 void *arg, 3493 struct sctp_cmd_seq *commands) 3494 { 3495 struct sctp_packet *packet = NULL; 3496 struct sctp_chunk *chunk = arg; 3497 struct sctp_chunk *abort; 3498 3499 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3500 if (!packet) 3501 return SCTP_DISPOSITION_NOMEM; 3502 3503 /* Make an ABORT. The T bit will be set if the asoc 3504 * is NULL. 3505 */ 3506 abort = sctp_make_abort(asoc, chunk, 0); 3507 if (!abort) { 3508 sctp_ootb_pkt_free(packet); 3509 return SCTP_DISPOSITION_NOMEM; 3510 } 3511 3512 /* Reflect vtag if T-Bit is set */ 3513 if (sctp_test_T_bit(abort)) 3514 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3515 3516 /* Set the skb to the belonging sock for accounting. */ 3517 abort->skb->sk = ep->base.sk; 3518 3519 sctp_packet_append_chunk(packet, abort); 3520 3521 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3522 3523 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3524 3525 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3526 return SCTP_DISPOSITION_CONSUME; 3527 } 3528 3529 /* Handling of SCTP Packets Containing an INIT Chunk Matching an 3530 * Existing Associations when the UDP encap port is incorrect. 3531 * 3532 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3533 */ 3534 static enum sctp_disposition sctp_sf_new_encap_port( 3535 struct net *net, 3536 const struct sctp_endpoint *ep, 3537 const struct sctp_association *asoc, 3538 const union sctp_subtype type, 3539 void *arg, 3540 struct sctp_cmd_seq *commands) 3541 { 3542 struct sctp_packet *packet = NULL; 3543 struct sctp_chunk *chunk = arg; 3544 struct sctp_chunk *abort; 3545 3546 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3547 if (!packet) 3548 return SCTP_DISPOSITION_NOMEM; 3549 3550 abort = sctp_make_new_encap_port(asoc, chunk); 3551 if (!abort) { 3552 sctp_ootb_pkt_free(packet); 3553 return SCTP_DISPOSITION_NOMEM; 3554 } 3555 3556 abort->skb->sk = ep->base.sk; 3557 3558 sctp_packet_append_chunk(packet, abort); 3559 3560 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3561 SCTP_PACKET(packet)); 3562 3563 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3564 3565 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3566 return SCTP_DISPOSITION_CONSUME; 3567 } 3568 3569 /* 3570 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3571 * event as ULP notification for each cause included in the chunk. 3572 * 3573 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3574 * 3575 * The return value is the disposition of the chunk. 3576 */ 3577 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3578 const struct sctp_endpoint *ep, 3579 const struct sctp_association *asoc, 3580 const union sctp_subtype type, 3581 void *arg, 3582 struct sctp_cmd_seq *commands) 3583 { 3584 struct sctp_chunk *chunk = arg; 3585 struct sctp_errhdr *err; 3586 3587 if (!sctp_vtag_verify(chunk, asoc)) 3588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3589 3590 /* Make sure that the ERROR chunk has a valid length. */ 3591 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3592 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3593 commands); 3594 sctp_walk_errors(err, chunk->chunk_hdr); 3595 if ((void *)err != (void *)chunk->chunk_end) 3596 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3597 (void *)err, commands); 3598 3599 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3600 SCTP_CHUNK(chunk)); 3601 3602 return SCTP_DISPOSITION_CONSUME; 3603 } 3604 3605 /* 3606 * Process an inbound SHUTDOWN ACK. 3607 * 3608 * From Section 9.2: 3609 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3610 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3611 * peer, and remove all record of the association. 3612 * 3613 * The return value is the disposition. 3614 */ 3615 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3616 const struct sctp_endpoint *ep, 3617 const struct sctp_association *asoc, 3618 const union sctp_subtype type, 3619 void *arg, 3620 struct sctp_cmd_seq *commands) 3621 { 3622 struct sctp_chunk *chunk = arg; 3623 struct sctp_chunk *reply; 3624 struct sctp_ulpevent *ev; 3625 3626 if (!sctp_vtag_verify(chunk, asoc)) 3627 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3628 3629 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3630 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3631 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3632 commands); 3633 /* 10.2 H) SHUTDOWN COMPLETE notification 3634 * 3635 * When SCTP completes the shutdown procedures (section 9.2) this 3636 * notification is passed to the upper layer. 3637 */ 3638 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3639 0, 0, 0, NULL, GFP_ATOMIC); 3640 if (!ev) 3641 goto nomem; 3642 3643 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3644 reply = sctp_make_shutdown_complete(asoc, chunk); 3645 if (!reply) 3646 goto nomem_chunk; 3647 3648 /* Do all the commands now (after allocation), so that we 3649 * have consistent state if memory allocation fails 3650 */ 3651 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3652 3653 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3654 * stop the T2-shutdown timer, 3655 */ 3656 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3657 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3658 3659 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3660 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3661 3662 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3663 SCTP_STATE(SCTP_STATE_CLOSED)); 3664 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3665 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3666 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3667 3668 /* ...and remove all record of the association. */ 3669 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3670 return SCTP_DISPOSITION_DELETE_TCB; 3671 3672 nomem_chunk: 3673 sctp_ulpevent_free(ev); 3674 nomem: 3675 return SCTP_DISPOSITION_NOMEM; 3676 } 3677 3678 /* 3679 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3680 * 3681 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3682 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3683 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3684 * packet must fill in the Verification Tag field of the outbound 3685 * packet with the Verification Tag received in the SHUTDOWN ACK and 3686 * set the T-bit in the Chunk Flags to indicate that the Verification 3687 * Tag is reflected. 3688 * 3689 * 8) The receiver should respond to the sender of the OOTB packet with 3690 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3691 * MUST fill in the Verification Tag field of the outbound packet 3692 * with the value found in the Verification Tag field of the OOTB 3693 * packet and set the T-bit in the Chunk Flags to indicate that the 3694 * Verification Tag is reflected. After sending this ABORT, the 3695 * receiver of the OOTB packet shall discard the OOTB packet and take 3696 * no further action. 3697 */ 3698 enum sctp_disposition sctp_sf_ootb(struct net *net, 3699 const struct sctp_endpoint *ep, 3700 const struct sctp_association *asoc, 3701 const union sctp_subtype type, 3702 void *arg, struct sctp_cmd_seq *commands) 3703 { 3704 struct sctp_chunk *chunk = arg; 3705 struct sk_buff *skb = chunk->skb; 3706 struct sctp_chunkhdr *ch; 3707 struct sctp_errhdr *err; 3708 int ootb_cookie_ack = 0; 3709 int ootb_shut_ack = 0; 3710 __u8 *ch_end; 3711 3712 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3713 3714 if (asoc && !sctp_vtag_verify(chunk, asoc)) 3715 asoc = NULL; 3716 3717 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3718 do { 3719 /* Report violation if the chunk is less then minimal */ 3720 if (ntohs(ch->length) < sizeof(*ch)) 3721 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3722 commands); 3723 3724 /* Report violation if chunk len overflows */ 3725 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3726 if (ch_end > skb_tail_pointer(skb)) 3727 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3728 commands); 3729 3730 /* Now that we know we at least have a chunk header, 3731 * do things that are type appropriate. 3732 */ 3733 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3734 ootb_shut_ack = 1; 3735 3736 /* RFC 2960, Section 3.3.7 3737 * Moreover, under any circumstances, an endpoint that 3738 * receives an ABORT MUST NOT respond to that ABORT by 3739 * sending an ABORT of its own. 3740 */ 3741 if (SCTP_CID_ABORT == ch->type) 3742 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3743 3744 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3745 * or a COOKIE ACK the SCTP Packet should be silently 3746 * discarded. 3747 */ 3748 3749 if (SCTP_CID_COOKIE_ACK == ch->type) 3750 ootb_cookie_ack = 1; 3751 3752 if (SCTP_CID_ERROR == ch->type) { 3753 sctp_walk_errors(err, ch) { 3754 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3755 ootb_cookie_ack = 1; 3756 break; 3757 } 3758 } 3759 } 3760 3761 ch = (struct sctp_chunkhdr *)ch_end; 3762 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); 3763 3764 if (ootb_shut_ack) 3765 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3766 else if (ootb_cookie_ack) 3767 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3768 else 3769 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3770 } 3771 3772 /* 3773 * Handle an "Out of the blue" SHUTDOWN ACK. 3774 * 3775 * Section: 8.4 5, sctpimpguide 2.41. 3776 * 3777 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3778 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3779 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3780 * packet must fill in the Verification Tag field of the outbound 3781 * packet with the Verification Tag received in the SHUTDOWN ACK and 3782 * set the T-bit in the Chunk Flags to indicate that the Verification 3783 * Tag is reflected. 3784 * 3785 * Inputs 3786 * (endpoint, asoc, type, arg, commands) 3787 * 3788 * Outputs 3789 * (enum sctp_disposition) 3790 * 3791 * The return value is the disposition of the chunk. 3792 */ 3793 static enum sctp_disposition sctp_sf_shut_8_4_5( 3794 struct net *net, 3795 const struct sctp_endpoint *ep, 3796 const struct sctp_association *asoc, 3797 const union sctp_subtype type, 3798 void *arg, 3799 struct sctp_cmd_seq *commands) 3800 { 3801 struct sctp_packet *packet = NULL; 3802 struct sctp_chunk *chunk = arg; 3803 struct sctp_chunk *shut; 3804 3805 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3806 if (!packet) 3807 return SCTP_DISPOSITION_NOMEM; 3808 3809 /* Make an SHUTDOWN_COMPLETE. 3810 * The T bit will be set if the asoc is NULL. 3811 */ 3812 shut = sctp_make_shutdown_complete(asoc, chunk); 3813 if (!shut) { 3814 sctp_ootb_pkt_free(packet); 3815 return SCTP_DISPOSITION_NOMEM; 3816 } 3817 3818 /* Reflect vtag if T-Bit is set */ 3819 if (sctp_test_T_bit(shut)) 3820 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3821 3822 /* Set the skb to the belonging sock for accounting. */ 3823 shut->skb->sk = ep->base.sk; 3824 3825 sctp_packet_append_chunk(packet, shut); 3826 3827 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3828 SCTP_PACKET(packet)); 3829 3830 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3831 3832 /* We need to discard the rest of the packet to prevent 3833 * potential boomming attacks from additional bundled chunks. 3834 * This is documented in SCTP Threats ID. 3835 */ 3836 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3837 } 3838 3839 /* 3840 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3841 * 3842 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3843 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3844 * procedures in section 8.4 SHOULD be followed, in other words it 3845 * should be treated as an Out Of The Blue packet. 3846 * [This means that we do NOT check the Verification Tag on these 3847 * chunks. --piggy ] 3848 * 3849 */ 3850 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3851 const struct sctp_endpoint *ep, 3852 const struct sctp_association *asoc, 3853 const union sctp_subtype type, 3854 void *arg, 3855 struct sctp_cmd_seq *commands) 3856 { 3857 struct sctp_chunk *chunk = arg; 3858 3859 if (!sctp_vtag_verify(chunk, asoc)) 3860 asoc = NULL; 3861 3862 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3863 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3864 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3865 commands); 3866 3867 /* Although we do have an association in this case, it corresponds 3868 * to a restarted association. So the packet is treated as an OOTB 3869 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3870 * called with a NULL association. 3871 */ 3872 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3873 3874 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3875 } 3876 3877 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3878 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3879 const struct sctp_endpoint *ep, 3880 const struct sctp_association *asoc, 3881 const union sctp_subtype type, 3882 void *arg, 3883 struct sctp_cmd_seq *commands) 3884 { 3885 struct sctp_paramhdr *err_param = NULL; 3886 struct sctp_chunk *asconf_ack = NULL; 3887 struct sctp_chunk *chunk = arg; 3888 struct sctp_addiphdr *hdr; 3889 __u32 serial; 3890 3891 if (!sctp_vtag_verify(chunk, asoc)) { 3892 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3893 SCTP_NULL()); 3894 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3895 } 3896 3897 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3898 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3899 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3900 commands); 3901 3902 /* ADD-IP: Section 4.1.1 3903 * This chunk MUST be sent in an authenticated way by using 3904 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3905 * is received unauthenticated it MUST be silently discarded as 3906 * described in [I-D.ietf-tsvwg-sctp-auth]. 3907 */ 3908 if (!asoc->peer.asconf_capable || 3909 (!net->sctp.addip_noauth && !chunk->auth)) 3910 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3911 3912 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3913 serial = ntohl(hdr->serial); 3914 3915 /* Verify the ASCONF chunk before processing it. */ 3916 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3917 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3918 (void *)err_param, commands); 3919 3920 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3921 * the endpoint stored in a new association variable 3922 * 'Peer-Serial-Number'. 3923 */ 3924 if (serial == asoc->peer.addip_serial + 1) { 3925 /* If this is the first instance of ASCONF in the packet, 3926 * we can clean our old ASCONF-ACKs. 3927 */ 3928 if (!chunk->has_asconf) 3929 sctp_assoc_clean_asconf_ack_cache(asoc); 3930 3931 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3932 * expected, process the ASCONF as described below and after 3933 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3934 * the response packet and cache a copy of it (in the event it 3935 * later needs to be retransmitted). 3936 * 3937 * Essentially, do V1-V5. 3938 */ 3939 asconf_ack = sctp_process_asconf((struct sctp_association *) 3940 asoc, chunk); 3941 if (!asconf_ack) 3942 return SCTP_DISPOSITION_NOMEM; 3943 } else if (serial < asoc->peer.addip_serial + 1) { 3944 /* ADDIP 5.2 E2) 3945 * If the value found in the Sequence Number is less than the 3946 * ('Peer- Sequence-Number' + 1), simply skip to the next 3947 * ASCONF, and include in the outbound response packet 3948 * any previously cached ASCONF-ACK response that was 3949 * sent and saved that matches the Sequence Number of the 3950 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3951 * Chunk exists. This will occur when an older ASCONF 3952 * arrives out of order. In such a case, the receiver 3953 * should skip the ASCONF Chunk and not include ASCONF-ACK 3954 * Chunk for that chunk. 3955 */ 3956 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3957 if (!asconf_ack) 3958 return SCTP_DISPOSITION_DISCARD; 3959 3960 /* Reset the transport so that we select the correct one 3961 * this time around. This is to make sure that we don't 3962 * accidentally use a stale transport that's been removed. 3963 */ 3964 asconf_ack->transport = NULL; 3965 } else { 3966 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3967 * it must be either a stale packet or from an attacker. 3968 */ 3969 return SCTP_DISPOSITION_DISCARD; 3970 } 3971 3972 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3973 * containing the ASCONF-ACK Chunks MUST be the source address of 3974 * the SCTP packet that held the ASCONF Chunks. 3975 * 3976 * To do this properly, we'll set the destination address of the chunk 3977 * and at the transmit time, will try look up the transport to use. 3978 * Since ASCONFs may be bundled, the correct transport may not be 3979 * created until we process the entire packet, thus this workaround. 3980 */ 3981 asconf_ack->dest = chunk->source; 3982 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3983 if (asoc->new_transport) { 3984 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3985 ((struct sctp_association *)asoc)->new_transport = NULL; 3986 } 3987 3988 return SCTP_DISPOSITION_CONSUME; 3989 } 3990 3991 static enum sctp_disposition sctp_send_next_asconf( 3992 struct net *net, 3993 const struct sctp_endpoint *ep, 3994 struct sctp_association *asoc, 3995 const union sctp_subtype type, 3996 struct sctp_cmd_seq *commands) 3997 { 3998 struct sctp_chunk *asconf; 3999 struct list_head *entry; 4000 4001 if (list_empty(&asoc->addip_chunk_list)) 4002 return SCTP_DISPOSITION_CONSUME; 4003 4004 entry = asoc->addip_chunk_list.next; 4005 asconf = list_entry(entry, struct sctp_chunk, list); 4006 4007 list_del_init(entry); 4008 sctp_chunk_hold(asconf); 4009 asoc->addip_last_asconf = asconf; 4010 4011 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 4012 } 4013 4014 /* 4015 * ADDIP Section 4.3 General rules for address manipulation 4016 * When building TLV parameters for the ASCONF Chunk that will add or 4017 * delete IP addresses the D0 to D13 rules should be applied: 4018 */ 4019 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 4020 const struct sctp_endpoint *ep, 4021 const struct sctp_association *asoc, 4022 const union sctp_subtype type, 4023 void *arg, 4024 struct sctp_cmd_seq *commands) 4025 { 4026 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 4027 struct sctp_paramhdr *err_param = NULL; 4028 struct sctp_chunk *asconf_ack = arg; 4029 struct sctp_addiphdr *addip_hdr; 4030 __u32 sent_serial, rcvd_serial; 4031 struct sctp_chunk *abort; 4032 4033 if (!sctp_vtag_verify(asconf_ack, asoc)) { 4034 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4035 SCTP_NULL()); 4036 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4037 } 4038 4039 /* Make sure that the ADDIP chunk has a valid length. */ 4040 if (!sctp_chunk_length_valid(asconf_ack, 4041 sizeof(struct sctp_addip_chunk))) 4042 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4043 commands); 4044 4045 /* ADD-IP, Section 4.1.2: 4046 * This chunk MUST be sent in an authenticated way by using 4047 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 4048 * is received unauthenticated it MUST be silently discarded as 4049 * described in [I-D.ietf-tsvwg-sctp-auth]. 4050 */ 4051 if (!asoc->peer.asconf_capable || 4052 (!net->sctp.addip_noauth && !asconf_ack->auth)) 4053 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4054 4055 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 4056 rcvd_serial = ntohl(addip_hdr->serial); 4057 4058 /* Verify the ASCONF-ACK chunk before processing it. */ 4059 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 4060 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4061 (void *)err_param, commands); 4062 4063 if (last_asconf) { 4064 addip_hdr = last_asconf->subh.addip_hdr; 4065 sent_serial = ntohl(addip_hdr->serial); 4066 } else { 4067 sent_serial = asoc->addip_serial - 1; 4068 } 4069 4070 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 4071 * equal to the next serial number to be used but no ASCONF chunk is 4072 * outstanding the endpoint MUST ABORT the association. Note that a 4073 * sequence number is greater than if it is no more than 2^^31-1 4074 * larger than the current sequence number (using serial arithmetic). 4075 */ 4076 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 4077 !(asoc->addip_last_asconf)) { 4078 abort = sctp_make_abort(asoc, asconf_ack, 4079 sizeof(struct sctp_errhdr)); 4080 if (abort) { 4081 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 4082 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4083 SCTP_CHUNK(abort)); 4084 } 4085 /* We are going to ABORT, so we might as well stop 4086 * processing the rest of the chunks in the packet. 4087 */ 4088 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4089 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4090 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4091 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4092 SCTP_ERROR(ECONNABORTED)); 4093 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4094 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4095 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4096 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4097 return SCTP_DISPOSITION_ABORT; 4098 } 4099 4100 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4101 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4102 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4103 4104 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4105 asconf_ack)) 4106 return sctp_send_next_asconf(net, ep, 4107 (struct sctp_association *)asoc, 4108 type, commands); 4109 4110 abort = sctp_make_abort(asoc, asconf_ack, 4111 sizeof(struct sctp_errhdr)); 4112 if (abort) { 4113 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4114 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4115 SCTP_CHUNK(abort)); 4116 } 4117 /* We are going to ABORT, so we might as well stop 4118 * processing the rest of the chunks in the packet. 4119 */ 4120 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4121 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4122 SCTP_ERROR(ECONNABORTED)); 4123 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4124 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4125 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4126 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4127 return SCTP_DISPOSITION_ABORT; 4128 } 4129 4130 return SCTP_DISPOSITION_DISCARD; 4131 } 4132 4133 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4134 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4135 const struct sctp_endpoint *ep, 4136 const struct sctp_association *asoc, 4137 const union sctp_subtype type, 4138 void *arg, 4139 struct sctp_cmd_seq *commands) 4140 { 4141 struct sctp_paramhdr *err_param = NULL; 4142 struct sctp_chunk *chunk = arg; 4143 struct sctp_reconf_chunk *hdr; 4144 union sctp_params param; 4145 4146 if (!sctp_vtag_verify(chunk, asoc)) { 4147 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4148 SCTP_NULL()); 4149 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4150 } 4151 4152 /* Make sure that the RECONF chunk has a valid length. */ 4153 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4154 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4155 commands); 4156 4157 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4158 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4159 (void *)err_param, commands); 4160 4161 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4162 sctp_walk_params(param, hdr) { 4163 struct sctp_chunk *reply = NULL; 4164 struct sctp_ulpevent *ev = NULL; 4165 4166 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4167 reply = sctp_process_strreset_outreq( 4168 (struct sctp_association *)asoc, param, &ev); 4169 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4170 reply = sctp_process_strreset_inreq( 4171 (struct sctp_association *)asoc, param, &ev); 4172 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4173 reply = sctp_process_strreset_tsnreq( 4174 (struct sctp_association *)asoc, param, &ev); 4175 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4176 reply = sctp_process_strreset_addstrm_out( 4177 (struct sctp_association *)asoc, param, &ev); 4178 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4179 reply = sctp_process_strreset_addstrm_in( 4180 (struct sctp_association *)asoc, param, &ev); 4181 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4182 reply = sctp_process_strreset_resp( 4183 (struct sctp_association *)asoc, param, &ev); 4184 4185 if (ev) 4186 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4187 SCTP_ULPEVENT(ev)); 4188 4189 if (reply) 4190 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4191 SCTP_CHUNK(reply)); 4192 } 4193 4194 return SCTP_DISPOSITION_CONSUME; 4195 } 4196 4197 /* 4198 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4199 * 4200 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4201 * its cumulative TSN point to the value carried in the FORWARD TSN 4202 * chunk, and then MUST further advance its cumulative TSN point locally 4203 * if possible. 4204 * After the above processing, the data receiver MUST stop reporting any 4205 * missing TSNs earlier than or equal to the new cumulative TSN point. 4206 * 4207 * Verification Tag: 8.5 Verification Tag [Normal verification] 4208 * 4209 * The return value is the disposition of the chunk. 4210 */ 4211 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4212 const struct sctp_endpoint *ep, 4213 const struct sctp_association *asoc, 4214 const union sctp_subtype type, 4215 void *arg, 4216 struct sctp_cmd_seq *commands) 4217 { 4218 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4219 struct sctp_chunk *chunk = arg; 4220 __u16 len; 4221 __u32 tsn; 4222 4223 if (!sctp_vtag_verify(chunk, asoc)) { 4224 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4225 SCTP_NULL()); 4226 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4227 } 4228 4229 if (!asoc->peer.prsctp_capable) 4230 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4231 4232 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4233 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4234 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4235 commands); 4236 4237 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4238 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4239 len = ntohs(chunk->chunk_hdr->length); 4240 len -= sizeof(struct sctp_chunkhdr); 4241 skb_pull(chunk->skb, len); 4242 4243 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4244 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4245 4246 /* The TSN is too high--silently discard the chunk and count on it 4247 * getting retransmitted later. 4248 */ 4249 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4250 goto discard_noforce; 4251 4252 if (!asoc->stream.si->validate_ftsn(chunk)) 4253 goto discard_noforce; 4254 4255 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4256 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4257 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4258 SCTP_CHUNK(chunk)); 4259 4260 /* Count this as receiving DATA. */ 4261 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4262 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4263 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4264 } 4265 4266 /* FIXME: For now send a SACK, but DATA processing may 4267 * send another. 4268 */ 4269 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4270 4271 return SCTP_DISPOSITION_CONSUME; 4272 4273 discard_noforce: 4274 return SCTP_DISPOSITION_DISCARD; 4275 } 4276 4277 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4278 struct net *net, 4279 const struct sctp_endpoint *ep, 4280 const struct sctp_association *asoc, 4281 const union sctp_subtype type, 4282 void *arg, 4283 struct sctp_cmd_seq *commands) 4284 { 4285 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4286 struct sctp_chunk *chunk = arg; 4287 __u16 len; 4288 __u32 tsn; 4289 4290 if (!sctp_vtag_verify(chunk, asoc)) { 4291 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4292 SCTP_NULL()); 4293 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4294 } 4295 4296 if (!asoc->peer.prsctp_capable) 4297 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4298 4299 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4300 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4301 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4302 commands); 4303 4304 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4305 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4306 len = ntohs(chunk->chunk_hdr->length); 4307 len -= sizeof(struct sctp_chunkhdr); 4308 skb_pull(chunk->skb, len); 4309 4310 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4311 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4312 4313 /* The TSN is too high--silently discard the chunk and count on it 4314 * getting retransmitted later. 4315 */ 4316 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4317 goto gen_shutdown; 4318 4319 if (!asoc->stream.si->validate_ftsn(chunk)) 4320 goto gen_shutdown; 4321 4322 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4323 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4324 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4325 SCTP_CHUNK(chunk)); 4326 4327 /* Go a head and force a SACK, since we are shutting down. */ 4328 gen_shutdown: 4329 /* Implementor's Guide. 4330 * 4331 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4332 * respond to each received packet containing one or more DATA chunk(s) 4333 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4334 */ 4335 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4336 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4337 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4338 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4339 4340 return SCTP_DISPOSITION_CONSUME; 4341 } 4342 4343 /* 4344 * SCTP-AUTH Section 6.3 Receiving authenticated chunks 4345 * 4346 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4347 * Identifier field. If this algorithm was not specified by the 4348 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4349 * during association setup, the AUTH chunk and all chunks after it MUST 4350 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4351 * defined in Section 4.1. 4352 * 4353 * If an endpoint with no shared key receives a Shared Key Identifier 4354 * other than 0, it MUST silently discard all authenticated chunks. If 4355 * the endpoint has at least one endpoint pair shared key for the peer, 4356 * it MUST use the key specified by the Shared Key Identifier if a 4357 * key has been configured for that Shared Key Identifier. If no 4358 * endpoint pair shared key has been configured for that Shared Key 4359 * Identifier, all authenticated chunks MUST be silently discarded. 4360 * 4361 * Verification Tag: 8.5 Verification Tag [Normal verification] 4362 * 4363 * The return value is the disposition of the chunk. 4364 */ 4365 static enum sctp_ierror sctp_sf_authenticate( 4366 const struct sctp_association *asoc, 4367 struct sctp_chunk *chunk) 4368 { 4369 struct sctp_shared_key *sh_key = NULL; 4370 struct sctp_authhdr *auth_hdr; 4371 __u8 *save_digest, *digest; 4372 const struct sctp_hmac *hmac; 4373 unsigned int sig_len; 4374 __u16 key_id; 4375 4376 /* Pull in the auth header, so we can do some more verification */ 4377 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4378 chunk->subh.auth_hdr = auth_hdr; 4379 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4380 4381 /* Make sure that we support the HMAC algorithm from the auth 4382 * chunk. 4383 */ 4384 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4385 return SCTP_IERROR_AUTH_BAD_HMAC; 4386 4387 /* Make sure that the provided shared key identifier has been 4388 * configured 4389 */ 4390 key_id = ntohs(auth_hdr->shkey_id); 4391 if (key_id != asoc->active_key_id) { 4392 sh_key = sctp_auth_get_shkey(asoc, key_id); 4393 if (!sh_key) 4394 return SCTP_IERROR_AUTH_BAD_KEYID; 4395 } 4396 4397 /* Make sure that the length of the signature matches what 4398 * we expect. 4399 */ 4400 sig_len = ntohs(chunk->chunk_hdr->length) - 4401 sizeof(struct sctp_auth_chunk); 4402 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4403 if (sig_len != hmac->hmac_len) 4404 return SCTP_IERROR_PROTO_VIOLATION; 4405 4406 /* Now that we've done validation checks, we can compute and 4407 * verify the hmac. The steps involved are: 4408 * 1. Save the digest from the chunk. 4409 * 2. Zero out the digest in the chunk. 4410 * 3. Compute the new digest 4411 * 4. Compare saved and new digests. 4412 */ 4413 digest = (u8 *)(auth_hdr + 1); 4414 skb_pull(chunk->skb, sig_len); 4415 4416 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4417 if (!save_digest) 4418 goto nomem; 4419 4420 memset(digest, 0, sig_len); 4421 4422 sctp_auth_calculate_hmac(asoc, chunk->skb, 4423 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4424 sh_key, GFP_ATOMIC); 4425 4426 /* Discard the packet if the digests do not match */ 4427 if (crypto_memneq(save_digest, digest, sig_len)) { 4428 kfree(save_digest); 4429 return SCTP_IERROR_BAD_SIG; 4430 } 4431 4432 kfree(save_digest); 4433 chunk->auth = 1; 4434 4435 return SCTP_IERROR_NO_ERROR; 4436 nomem: 4437 return SCTP_IERROR_NOMEM; 4438 } 4439 4440 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4441 const struct sctp_endpoint *ep, 4442 const struct sctp_association *asoc, 4443 const union sctp_subtype type, 4444 void *arg, struct sctp_cmd_seq *commands) 4445 { 4446 struct sctp_chunk *chunk = arg; 4447 struct sctp_authhdr *auth_hdr; 4448 struct sctp_chunk *err_chunk; 4449 enum sctp_ierror error; 4450 4451 /* Make sure that the peer has AUTH capable */ 4452 if (!asoc->peer.auth_capable) 4453 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4454 4455 if (!sctp_vtag_verify(chunk, asoc)) { 4456 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4457 SCTP_NULL()); 4458 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4459 } 4460 4461 /* Make sure that the AUTH chunk has valid length. */ 4462 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4463 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4464 commands); 4465 4466 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4467 error = sctp_sf_authenticate(asoc, chunk); 4468 switch (error) { 4469 case SCTP_IERROR_AUTH_BAD_HMAC: 4470 /* Generate the ERROR chunk and discard the rest 4471 * of the packet 4472 */ 4473 err_chunk = sctp_make_op_error(asoc, chunk, 4474 SCTP_ERROR_UNSUP_HMAC, 4475 &auth_hdr->hmac_id, 4476 sizeof(__u16), 0); 4477 if (err_chunk) { 4478 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4479 SCTP_CHUNK(err_chunk)); 4480 } 4481 fallthrough; 4482 case SCTP_IERROR_AUTH_BAD_KEYID: 4483 case SCTP_IERROR_BAD_SIG: 4484 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4485 4486 case SCTP_IERROR_PROTO_VIOLATION: 4487 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4488 commands); 4489 4490 case SCTP_IERROR_NOMEM: 4491 return SCTP_DISPOSITION_NOMEM; 4492 4493 default: /* Prevent gcc warnings */ 4494 break; 4495 } 4496 4497 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4498 struct sctp_ulpevent *ev; 4499 4500 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4501 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4502 4503 if (!ev) 4504 return SCTP_DISPOSITION_NOMEM; 4505 4506 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4507 SCTP_ULPEVENT(ev)); 4508 } 4509 4510 return SCTP_DISPOSITION_CONSUME; 4511 } 4512 4513 /* 4514 * Process an unknown chunk. 4515 * 4516 * Section: 3.2. Also, 2.1 in the implementor's guide. 4517 * 4518 * Chunk Types are encoded such that the highest-order two bits specify 4519 * the action that must be taken if the processing endpoint does not 4520 * recognize the Chunk Type. 4521 * 4522 * 00 - Stop processing this SCTP packet and discard it, do not process 4523 * any further chunks within it. 4524 * 4525 * 01 - Stop processing this SCTP packet and discard it, do not process 4526 * any further chunks within it, and report the unrecognized 4527 * chunk in an 'Unrecognized Chunk Type'. 4528 * 4529 * 10 - Skip this chunk and continue processing. 4530 * 4531 * 11 - Skip this chunk and continue processing, but report in an ERROR 4532 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4533 * 4534 * The return value is the disposition of the chunk. 4535 */ 4536 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4537 const struct sctp_endpoint *ep, 4538 const struct sctp_association *asoc, 4539 const union sctp_subtype type, 4540 void *arg, 4541 struct sctp_cmd_seq *commands) 4542 { 4543 struct sctp_chunk *unk_chunk = arg; 4544 struct sctp_chunk *err_chunk; 4545 struct sctp_chunkhdr *hdr; 4546 4547 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4548 4549 if (!sctp_vtag_verify(unk_chunk, asoc)) 4550 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4551 4552 /* Make sure that the chunk has a valid length. 4553 * Since we don't know the chunk type, we use a general 4554 * chunkhdr structure to make a comparison. 4555 */ 4556 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4557 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4558 commands); 4559 4560 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4561 case SCTP_CID_ACTION_DISCARD: 4562 /* Discard the packet. */ 4563 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4564 case SCTP_CID_ACTION_DISCARD_ERR: 4565 /* Generate an ERROR chunk as response. */ 4566 hdr = unk_chunk->chunk_hdr; 4567 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4568 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4569 SCTP_PAD4(ntohs(hdr->length)), 4570 0); 4571 if (err_chunk) { 4572 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4573 SCTP_CHUNK(err_chunk)); 4574 } 4575 4576 /* Discard the packet. */ 4577 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4578 return SCTP_DISPOSITION_CONSUME; 4579 case SCTP_CID_ACTION_SKIP: 4580 /* Skip the chunk. */ 4581 return SCTP_DISPOSITION_DISCARD; 4582 case SCTP_CID_ACTION_SKIP_ERR: 4583 /* Generate an ERROR chunk as response. */ 4584 hdr = unk_chunk->chunk_hdr; 4585 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4586 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4587 SCTP_PAD4(ntohs(hdr->length)), 4588 0); 4589 if (err_chunk) { 4590 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4591 SCTP_CHUNK(err_chunk)); 4592 } 4593 /* Skip the chunk. */ 4594 return SCTP_DISPOSITION_CONSUME; 4595 default: 4596 break; 4597 } 4598 4599 return SCTP_DISPOSITION_DISCARD; 4600 } 4601 4602 /* 4603 * Discard the chunk. 4604 * 4605 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4606 * [Too numerous to mention...] 4607 * Verification Tag: No verification needed. 4608 * Inputs 4609 * (endpoint, asoc, chunk) 4610 * 4611 * Outputs 4612 * (asoc, reply_msg, msg_up, timers, counters) 4613 * 4614 * The return value is the disposition of the chunk. 4615 */ 4616 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4617 const struct sctp_endpoint *ep, 4618 const struct sctp_association *asoc, 4619 const union sctp_subtype type, 4620 void *arg, 4621 struct sctp_cmd_seq *commands) 4622 { 4623 struct sctp_chunk *chunk = arg; 4624 4625 if (asoc && !sctp_vtag_verify(chunk, asoc)) 4626 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4627 4628 /* Make sure that the chunk has a valid length. 4629 * Since we don't know the chunk type, we use a general 4630 * chunkhdr structure to make a comparison. 4631 */ 4632 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4633 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4634 commands); 4635 4636 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4637 4638 return SCTP_DISPOSITION_DISCARD; 4639 } 4640 4641 /* 4642 * Discard the whole packet. 4643 * 4644 * Section: 8.4 2) 4645 * 4646 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4647 * silently discard the OOTB packet and take no further action. 4648 * 4649 * Verification Tag: No verification necessary 4650 * 4651 * Inputs 4652 * (endpoint, asoc, chunk) 4653 * 4654 * Outputs 4655 * (asoc, reply_msg, msg_up, timers, counters) 4656 * 4657 * The return value is the disposition of the chunk. 4658 */ 4659 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4660 const struct sctp_endpoint *ep, 4661 const struct sctp_association *asoc, 4662 const union sctp_subtype type, 4663 void *arg, struct sctp_cmd_seq *commands) 4664 { 4665 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4666 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4667 4668 return SCTP_DISPOSITION_CONSUME; 4669 } 4670 4671 4672 /* 4673 * The other end is violating protocol. 4674 * 4675 * Section: Not specified 4676 * Verification Tag: Not specified 4677 * Inputs 4678 * (endpoint, asoc, chunk) 4679 * 4680 * Outputs 4681 * (asoc, reply_msg, msg_up, timers, counters) 4682 * 4683 * We simply tag the chunk as a violation. The state machine will log 4684 * the violation and continue. 4685 */ 4686 enum sctp_disposition sctp_sf_violation(struct net *net, 4687 const struct sctp_endpoint *ep, 4688 const struct sctp_association *asoc, 4689 const union sctp_subtype type, 4690 void *arg, 4691 struct sctp_cmd_seq *commands) 4692 { 4693 struct sctp_chunk *chunk = arg; 4694 4695 if (!sctp_vtag_verify(chunk, asoc)) 4696 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4697 4698 /* Make sure that the chunk has a valid length. */ 4699 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4700 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4701 commands); 4702 4703 return SCTP_DISPOSITION_VIOLATION; 4704 } 4705 4706 /* 4707 * Common function to handle a protocol violation. 4708 */ 4709 static enum sctp_disposition sctp_sf_abort_violation( 4710 struct net *net, 4711 const struct sctp_endpoint *ep, 4712 const struct sctp_association *asoc, 4713 void *arg, 4714 struct sctp_cmd_seq *commands, 4715 const __u8 *payload, 4716 const size_t paylen) 4717 { 4718 struct sctp_packet *packet = NULL; 4719 struct sctp_chunk *chunk = arg; 4720 struct sctp_chunk *abort = NULL; 4721 4722 /* SCTP-AUTH, Section 6.3: 4723 * It should be noted that if the receiver wants to tear 4724 * down an association in an authenticated way only, the 4725 * handling of malformed packets should not result in 4726 * tearing down the association. 4727 * 4728 * This means that if we only want to abort associations 4729 * in an authenticated way (i.e AUTH+ABORT), then we 4730 * can't destroy this association just because the packet 4731 * was malformed. 4732 */ 4733 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4734 goto discard; 4735 4736 /* Make the abort chunk. */ 4737 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4738 if (!abort) 4739 goto nomem; 4740 4741 if (asoc) { 4742 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4743 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4744 !asoc->peer.i.init_tag) { 4745 struct sctp_initack_chunk *initack; 4746 4747 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4748 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4749 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4750 else { 4751 unsigned int inittag; 4752 4753 inittag = ntohl(initack->init_hdr.init_tag); 4754 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4755 SCTP_U32(inittag)); 4756 } 4757 } 4758 4759 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4760 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4761 4762 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4763 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4764 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4765 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4766 SCTP_ERROR(ECONNREFUSED)); 4767 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4768 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4769 } else { 4770 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4771 SCTP_ERROR(ECONNABORTED)); 4772 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4773 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4774 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4775 } 4776 } else { 4777 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4778 4779 if (!packet) 4780 goto nomem_pkt; 4781 4782 if (sctp_test_T_bit(abort)) 4783 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4784 4785 abort->skb->sk = ep->base.sk; 4786 4787 sctp_packet_append_chunk(packet, abort); 4788 4789 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4790 SCTP_PACKET(packet)); 4791 4792 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4793 } 4794 4795 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4796 4797 discard: 4798 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4799 return SCTP_DISPOSITION_ABORT; 4800 4801 nomem_pkt: 4802 sctp_chunk_free(abort); 4803 nomem: 4804 return SCTP_DISPOSITION_NOMEM; 4805 } 4806 4807 /* 4808 * Handle a protocol violation when the chunk length is invalid. 4809 * "Invalid" length is identified as smaller than the minimal length a 4810 * given chunk can be. For example, a SACK chunk has invalid length 4811 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4812 * 4813 * We inform the other end by sending an ABORT with a Protocol Violation 4814 * error code. 4815 * 4816 * Section: Not specified 4817 * Verification Tag: Nothing to do 4818 * Inputs 4819 * (endpoint, asoc, chunk) 4820 * 4821 * Outputs 4822 * (reply_msg, msg_up, counters) 4823 * 4824 * Generate an ABORT chunk and terminate the association. 4825 */ 4826 static enum sctp_disposition sctp_sf_violation_chunklen( 4827 struct net *net, 4828 const struct sctp_endpoint *ep, 4829 const struct sctp_association *asoc, 4830 const union sctp_subtype type, 4831 void *arg, 4832 struct sctp_cmd_seq *commands) 4833 { 4834 static const char err_str[] = "The following chunk had invalid length:"; 4835 4836 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4837 sizeof(err_str)); 4838 } 4839 4840 /* 4841 * Handle a protocol violation when the parameter length is invalid. 4842 * If the length is smaller than the minimum length of a given parameter, 4843 * or accumulated length in multi parameters exceeds the end of the chunk, 4844 * the length is considered as invalid. 4845 */ 4846 static enum sctp_disposition sctp_sf_violation_paramlen( 4847 struct net *net, 4848 const struct sctp_endpoint *ep, 4849 const struct sctp_association *asoc, 4850 const union sctp_subtype type, 4851 void *arg, void *ext, 4852 struct sctp_cmd_seq *commands) 4853 { 4854 struct sctp_paramhdr *param = ext; 4855 struct sctp_chunk *abort = NULL; 4856 struct sctp_chunk *chunk = arg; 4857 4858 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4859 goto discard; 4860 4861 /* Make the abort chunk. */ 4862 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4863 if (!abort) 4864 goto nomem; 4865 4866 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4867 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4868 4869 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4870 SCTP_ERROR(ECONNABORTED)); 4871 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4872 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4873 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4874 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4875 4876 discard: 4877 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4878 return SCTP_DISPOSITION_ABORT; 4879 nomem: 4880 return SCTP_DISPOSITION_NOMEM; 4881 } 4882 4883 /* Handle a protocol violation when the peer trying to advance the 4884 * cumulative tsn ack to a point beyond the max tsn currently sent. 4885 * 4886 * We inform the other end by sending an ABORT with a Protocol Violation 4887 * error code. 4888 */ 4889 static enum sctp_disposition sctp_sf_violation_ctsn( 4890 struct net *net, 4891 const struct sctp_endpoint *ep, 4892 const struct sctp_association *asoc, 4893 const union sctp_subtype type, 4894 void *arg, 4895 struct sctp_cmd_seq *commands) 4896 { 4897 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4898 4899 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4900 sizeof(err_str)); 4901 } 4902 4903 /* Handle protocol violation of an invalid chunk bundling. For example, 4904 * when we have an association and we receive bundled INIT-ACK, or 4905 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle" 4906 * statement from the specs. Additionally, there might be an attacker 4907 * on the path and we may not want to continue this communication. 4908 */ 4909 static enum sctp_disposition sctp_sf_violation_chunk( 4910 struct net *net, 4911 const struct sctp_endpoint *ep, 4912 const struct sctp_association *asoc, 4913 const union sctp_subtype type, 4914 void *arg, 4915 struct sctp_cmd_seq *commands) 4916 { 4917 static const char err_str[] = "The following chunk violates protocol:"; 4918 4919 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4920 sizeof(err_str)); 4921 } 4922 /*************************************************************************** 4923 * These are the state functions for handling primitive (Section 10) events. 4924 ***************************************************************************/ 4925 /* 4926 * sctp_sf_do_prm_asoc 4927 * 4928 * Section: 10.1 ULP-to-SCTP 4929 * B) Associate 4930 * 4931 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4932 * outbound stream count) 4933 * -> association id [,destination transport addr list] [,outbound stream 4934 * count] 4935 * 4936 * This primitive allows the upper layer to initiate an association to a 4937 * specific peer endpoint. 4938 * 4939 * The peer endpoint shall be specified by one of the transport addresses 4940 * which defines the endpoint (see Section 1.4). If the local SCTP 4941 * instance has not been initialized, the ASSOCIATE is considered an 4942 * error. 4943 * [This is not relevant for the kernel implementation since we do all 4944 * initialization at boot time. It we hadn't initialized we wouldn't 4945 * get anywhere near this code.] 4946 * 4947 * An association id, which is a local handle to the SCTP association, 4948 * will be returned on successful establishment of the association. If 4949 * SCTP is not able to open an SCTP association with the peer endpoint, 4950 * an error is returned. 4951 * [In the kernel implementation, the struct sctp_association needs to 4952 * be created BEFORE causing this primitive to run.] 4953 * 4954 * Other association parameters may be returned, including the 4955 * complete destination transport addresses of the peer as well as the 4956 * outbound stream count of the local endpoint. One of the transport 4957 * address from the returned destination addresses will be selected by 4958 * the local endpoint as default primary path for sending SCTP packets 4959 * to this peer. The returned "destination transport addr list" can 4960 * be used by the ULP to change the default primary path or to force 4961 * sending a packet to a specific transport address. [All of this 4962 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4963 * function.] 4964 * 4965 * Mandatory attributes: 4966 * 4967 * o local SCTP instance name - obtained from the INITIALIZE operation. 4968 * [This is the argument asoc.] 4969 * o destination transport addr - specified as one of the transport 4970 * addresses of the peer endpoint with which the association is to be 4971 * established. 4972 * [This is asoc->peer.active_path.] 4973 * o outbound stream count - the number of outbound streams the ULP 4974 * would like to open towards this peer endpoint. 4975 * [BUG: This is not currently implemented.] 4976 * Optional attributes: 4977 * 4978 * None. 4979 * 4980 * The return value is a disposition. 4981 */ 4982 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4983 const struct sctp_endpoint *ep, 4984 const struct sctp_association *asoc, 4985 const union sctp_subtype type, 4986 void *arg, 4987 struct sctp_cmd_seq *commands) 4988 { 4989 struct sctp_association *my_asoc; 4990 struct sctp_chunk *repl; 4991 4992 /* The comment below says that we enter COOKIE-WAIT AFTER 4993 * sending the INIT, but that doesn't actually work in our 4994 * implementation... 4995 */ 4996 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4997 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4998 4999 /* RFC 2960 5.1 Normal Establishment of an Association 5000 * 5001 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 5002 * must provide its Verification Tag (Tag_A) in the Initiate 5003 * Tag field. Tag_A SHOULD be a random number in the range of 5004 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 5005 */ 5006 5007 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 5008 if (!repl) 5009 goto nomem; 5010 5011 /* Choose transport for INIT. */ 5012 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5013 SCTP_CHUNK(repl)); 5014 5015 /* Cast away the const modifier, as we want to just 5016 * rerun it through as a sideffect. 5017 */ 5018 my_asoc = (struct sctp_association *)asoc; 5019 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 5020 5021 /* After sending the INIT, "A" starts the T1-init timer and 5022 * enters the COOKIE-WAIT state. 5023 */ 5024 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5025 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5027 return SCTP_DISPOSITION_CONSUME; 5028 5029 nomem: 5030 return SCTP_DISPOSITION_NOMEM; 5031 } 5032 5033 /* 5034 * Process the SEND primitive. 5035 * 5036 * Section: 10.1 ULP-to-SCTP 5037 * E) Send 5038 * 5039 * Format: SEND(association id, buffer address, byte count [,context] 5040 * [,stream id] [,life time] [,destination transport address] 5041 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 5042 * -> result 5043 * 5044 * This is the main method to send user data via SCTP. 5045 * 5046 * Mandatory attributes: 5047 * 5048 * o association id - local handle to the SCTP association 5049 * 5050 * o buffer address - the location where the user message to be 5051 * transmitted is stored; 5052 * 5053 * o byte count - The size of the user data in number of bytes; 5054 * 5055 * Optional attributes: 5056 * 5057 * o context - an optional 32 bit integer that will be carried in the 5058 * sending failure notification to the ULP if the transportation of 5059 * this User Message fails. 5060 * 5061 * o stream id - to indicate which stream to send the data on. If not 5062 * specified, stream 0 will be used. 5063 * 5064 * o life time - specifies the life time of the user data. The user data 5065 * will not be sent by SCTP after the life time expires. This 5066 * parameter can be used to avoid efforts to transmit stale 5067 * user messages. SCTP notifies the ULP if the data cannot be 5068 * initiated to transport (i.e. sent to the destination via SCTP's 5069 * send primitive) within the life time variable. However, the 5070 * user data will be transmitted if SCTP has attempted to transmit a 5071 * chunk before the life time expired. 5072 * 5073 * o destination transport address - specified as one of the destination 5074 * transport addresses of the peer endpoint to which this packet 5075 * should be sent. Whenever possible, SCTP should use this destination 5076 * transport address for sending the packets, instead of the current 5077 * primary path. 5078 * 5079 * o unorder flag - this flag, if present, indicates that the user 5080 * would like the data delivered in an unordered fashion to the peer 5081 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 5082 * message). 5083 * 5084 * o no-bundle flag - instructs SCTP not to bundle this user data with 5085 * other outbound DATA chunks. SCTP MAY still bundle even when 5086 * this flag is present, when faced with network congestion. 5087 * 5088 * o payload protocol-id - A 32 bit unsigned integer that is to be 5089 * passed to the peer indicating the type of payload protocol data 5090 * being transmitted. This value is passed as opaque data by SCTP. 5091 * 5092 * The return value is the disposition. 5093 */ 5094 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5095 const struct sctp_endpoint *ep, 5096 const struct sctp_association *asoc, 5097 const union sctp_subtype type, 5098 void *arg, 5099 struct sctp_cmd_seq *commands) 5100 { 5101 struct sctp_datamsg *msg = arg; 5102 5103 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5104 return SCTP_DISPOSITION_CONSUME; 5105 } 5106 5107 /* 5108 * Process the SHUTDOWN primitive. 5109 * 5110 * Section: 10.1: 5111 * C) Shutdown 5112 * 5113 * Format: SHUTDOWN(association id) 5114 * -> result 5115 * 5116 * Gracefully closes an association. Any locally queued user data 5117 * will be delivered to the peer. The association will be terminated only 5118 * after the peer acknowledges all the SCTP packets sent. A success code 5119 * will be returned on successful termination of the association. If 5120 * attempting to terminate the association results in a failure, an error 5121 * code shall be returned. 5122 * 5123 * Mandatory attributes: 5124 * 5125 * o association id - local handle to the SCTP association 5126 * 5127 * Optional attributes: 5128 * 5129 * None. 5130 * 5131 * The return value is the disposition. 5132 */ 5133 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5134 struct net *net, 5135 const struct sctp_endpoint *ep, 5136 const struct sctp_association *asoc, 5137 const union sctp_subtype type, 5138 void *arg, 5139 struct sctp_cmd_seq *commands) 5140 { 5141 enum sctp_disposition disposition; 5142 5143 /* From 9.2 Shutdown of an Association 5144 * Upon receipt of the SHUTDOWN primitive from its upper 5145 * layer, the endpoint enters SHUTDOWN-PENDING state and 5146 * remains there until all outstanding data has been 5147 * acknowledged by its peer. The endpoint accepts no new data 5148 * from its upper layer, but retransmits data to the far end 5149 * if necessary to fill gaps. 5150 */ 5151 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5152 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5153 5154 disposition = SCTP_DISPOSITION_CONSUME; 5155 if (sctp_outq_is_empty(&asoc->outqueue)) { 5156 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5157 arg, commands); 5158 } 5159 5160 return disposition; 5161 } 5162 5163 /* 5164 * Process the ABORT primitive. 5165 * 5166 * Section: 10.1: 5167 * C) Abort 5168 * 5169 * Format: Abort(association id [, cause code]) 5170 * -> result 5171 * 5172 * Ungracefully closes an association. Any locally queued user data 5173 * will be discarded and an ABORT chunk is sent to the peer. A success code 5174 * will be returned on successful abortion of the association. If 5175 * attempting to abort the association results in a failure, an error 5176 * code shall be returned. 5177 * 5178 * Mandatory attributes: 5179 * 5180 * o association id - local handle to the SCTP association 5181 * 5182 * Optional attributes: 5183 * 5184 * o cause code - reason of the abort to be passed to the peer 5185 * 5186 * None. 5187 * 5188 * The return value is the disposition. 5189 */ 5190 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5191 struct net *net, 5192 const struct sctp_endpoint *ep, 5193 const struct sctp_association *asoc, 5194 const union sctp_subtype type, 5195 void *arg, 5196 struct sctp_cmd_seq *commands) 5197 { 5198 /* From 9.1 Abort of an Association 5199 * Upon receipt of the ABORT primitive from its upper 5200 * layer, the endpoint enters CLOSED state and 5201 * discard all outstanding data has been 5202 * acknowledged by its peer. The endpoint accepts no new data 5203 * from its upper layer, but retransmits data to the far end 5204 * if necessary to fill gaps. 5205 */ 5206 struct sctp_chunk *abort = arg; 5207 5208 if (abort) 5209 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5210 5211 /* Even if we can't send the ABORT due to low memory delete the 5212 * TCB. This is a departure from our typical NOMEM handling. 5213 */ 5214 5215 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5216 SCTP_ERROR(ECONNABORTED)); 5217 /* Delete the established association. */ 5218 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5219 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5220 5221 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5222 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5223 5224 return SCTP_DISPOSITION_ABORT; 5225 } 5226 5227 /* We tried an illegal operation on an association which is closed. */ 5228 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5229 const struct sctp_endpoint *ep, 5230 const struct sctp_association *asoc, 5231 const union sctp_subtype type, 5232 void *arg, 5233 struct sctp_cmd_seq *commands) 5234 { 5235 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5236 return SCTP_DISPOSITION_CONSUME; 5237 } 5238 5239 /* We tried an illegal operation on an association which is shutting 5240 * down. 5241 */ 5242 enum sctp_disposition sctp_sf_error_shutdown( 5243 struct net *net, 5244 const struct sctp_endpoint *ep, 5245 const struct sctp_association *asoc, 5246 const union sctp_subtype type, 5247 void *arg, 5248 struct sctp_cmd_seq *commands) 5249 { 5250 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5251 SCTP_ERROR(-ESHUTDOWN)); 5252 return SCTP_DISPOSITION_CONSUME; 5253 } 5254 5255 /* 5256 * sctp_cookie_wait_prm_shutdown 5257 * 5258 * Section: 4 Note: 2 5259 * Verification Tag: 5260 * Inputs 5261 * (endpoint, asoc) 5262 * 5263 * The RFC does not explicitly address this issue, but is the route through the 5264 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5265 * 5266 * Outputs 5267 * (timers) 5268 */ 5269 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5270 struct net *net, 5271 const struct sctp_endpoint *ep, 5272 const struct sctp_association *asoc, 5273 const union sctp_subtype type, 5274 void *arg, 5275 struct sctp_cmd_seq *commands) 5276 { 5277 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5278 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5279 5280 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5281 SCTP_STATE(SCTP_STATE_CLOSED)); 5282 5283 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5284 5285 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5286 5287 return SCTP_DISPOSITION_DELETE_TCB; 5288 } 5289 5290 /* 5291 * sctp_cookie_echoed_prm_shutdown 5292 * 5293 * Section: 4 Note: 2 5294 * Verification Tag: 5295 * Inputs 5296 * (endpoint, asoc) 5297 * 5298 * The RFC does not explicitly address this issue, but is the route through the 5299 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5300 * 5301 * Outputs 5302 * (timers) 5303 */ 5304 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5305 struct net *net, 5306 const struct sctp_endpoint *ep, 5307 const struct sctp_association *asoc, 5308 const union sctp_subtype type, 5309 void *arg, 5310 struct sctp_cmd_seq *commands) 5311 { 5312 /* There is a single T1 timer, so we should be able to use 5313 * common function with the COOKIE-WAIT state. 5314 */ 5315 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5316 } 5317 5318 /* 5319 * sctp_sf_cookie_wait_prm_abort 5320 * 5321 * Section: 4 Note: 2 5322 * Verification Tag: 5323 * Inputs 5324 * (endpoint, asoc) 5325 * 5326 * The RFC does not explicitly address this issue, but is the route through the 5327 * state table when someone issues an abort while in COOKIE_WAIT state. 5328 * 5329 * Outputs 5330 * (timers) 5331 */ 5332 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5333 struct net *net, 5334 const struct sctp_endpoint *ep, 5335 const struct sctp_association *asoc, 5336 const union sctp_subtype type, 5337 void *arg, 5338 struct sctp_cmd_seq *commands) 5339 { 5340 struct sctp_chunk *abort = arg; 5341 5342 /* Stop T1-init timer */ 5343 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5344 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5345 5346 if (abort) 5347 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5348 5349 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5350 SCTP_STATE(SCTP_STATE_CLOSED)); 5351 5352 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5353 5354 /* Even if we can't send the ABORT due to low memory delete the 5355 * TCB. This is a departure from our typical NOMEM handling. 5356 */ 5357 5358 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5359 SCTP_ERROR(ECONNREFUSED)); 5360 /* Delete the established association. */ 5361 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5362 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5363 5364 return SCTP_DISPOSITION_ABORT; 5365 } 5366 5367 /* 5368 * sctp_sf_cookie_echoed_prm_abort 5369 * 5370 * Section: 4 Note: 3 5371 * Verification Tag: 5372 * Inputs 5373 * (endpoint, asoc) 5374 * 5375 * The RFC does not explcitly address this issue, but is the route through the 5376 * state table when someone issues an abort while in COOKIE_ECHOED state. 5377 * 5378 * Outputs 5379 * (timers) 5380 */ 5381 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5382 struct net *net, 5383 const struct sctp_endpoint *ep, 5384 const struct sctp_association *asoc, 5385 const union sctp_subtype type, 5386 void *arg, 5387 struct sctp_cmd_seq *commands) 5388 { 5389 /* There is a single T1 timer, so we should be able to use 5390 * common function with the COOKIE-WAIT state. 5391 */ 5392 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5393 } 5394 5395 /* 5396 * sctp_sf_shutdown_pending_prm_abort 5397 * 5398 * Inputs 5399 * (endpoint, asoc) 5400 * 5401 * The RFC does not explicitly address this issue, but is the route through the 5402 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5403 * 5404 * Outputs 5405 * (timers) 5406 */ 5407 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5408 struct net *net, 5409 const struct sctp_endpoint *ep, 5410 const struct sctp_association *asoc, 5411 const union sctp_subtype type, 5412 void *arg, 5413 struct sctp_cmd_seq *commands) 5414 { 5415 /* Stop the T5-shutdown guard timer. */ 5416 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5417 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5418 5419 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5420 } 5421 5422 /* 5423 * sctp_sf_shutdown_sent_prm_abort 5424 * 5425 * Inputs 5426 * (endpoint, asoc) 5427 * 5428 * The RFC does not explicitly address this issue, but is the route through the 5429 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5430 * 5431 * Outputs 5432 * (timers) 5433 */ 5434 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5435 struct net *net, 5436 const struct sctp_endpoint *ep, 5437 const struct sctp_association *asoc, 5438 const union sctp_subtype type, 5439 void *arg, 5440 struct sctp_cmd_seq *commands) 5441 { 5442 /* Stop the T2-shutdown timer. */ 5443 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5444 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5445 5446 /* Stop the T5-shutdown guard timer. */ 5447 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5448 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5449 5450 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5451 } 5452 5453 /* 5454 * sctp_sf_cookie_echoed_prm_abort 5455 * 5456 * Inputs 5457 * (endpoint, asoc) 5458 * 5459 * The RFC does not explcitly address this issue, but is the route through the 5460 * state table when someone issues an abort while in COOKIE_ECHOED state. 5461 * 5462 * Outputs 5463 * (timers) 5464 */ 5465 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5466 struct net *net, 5467 const struct sctp_endpoint *ep, 5468 const struct sctp_association *asoc, 5469 const union sctp_subtype type, 5470 void *arg, 5471 struct sctp_cmd_seq *commands) 5472 { 5473 /* The same T2 timer, so we should be able to use 5474 * common function with the SHUTDOWN-SENT state. 5475 */ 5476 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5477 } 5478 5479 /* 5480 * Process the REQUESTHEARTBEAT primitive 5481 * 5482 * 10.1 ULP-to-SCTP 5483 * J) Request Heartbeat 5484 * 5485 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5486 * 5487 * -> result 5488 * 5489 * Instructs the local endpoint to perform a HeartBeat on the specified 5490 * destination transport address of the given association. The returned 5491 * result should indicate whether the transmission of the HEARTBEAT 5492 * chunk to the destination address is successful. 5493 * 5494 * Mandatory attributes: 5495 * 5496 * o association id - local handle to the SCTP association 5497 * 5498 * o destination transport address - the transport address of the 5499 * association on which a heartbeat should be issued. 5500 */ 5501 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5502 struct net *net, 5503 const struct sctp_endpoint *ep, 5504 const struct sctp_association *asoc, 5505 const union sctp_subtype type, 5506 void *arg, 5507 struct sctp_cmd_seq *commands) 5508 { 5509 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5510 (struct sctp_transport *)arg, commands)) 5511 return SCTP_DISPOSITION_NOMEM; 5512 5513 /* 5514 * RFC 2960 (bis), section 8.3 5515 * 5516 * D) Request an on-demand HEARTBEAT on a specific destination 5517 * transport address of a given association. 5518 * 5519 * The endpoint should increment the respective error counter of 5520 * the destination transport address each time a HEARTBEAT is sent 5521 * to that address and not acknowledged within one RTO. 5522 * 5523 */ 5524 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5525 SCTP_TRANSPORT(arg)); 5526 return SCTP_DISPOSITION_CONSUME; 5527 } 5528 5529 /* 5530 * ADDIP Section 4.1 ASCONF Chunk Procedures 5531 * When an endpoint has an ASCONF signaled change to be sent to the 5532 * remote endpoint it should do A1 to A9 5533 */ 5534 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5535 const struct sctp_endpoint *ep, 5536 const struct sctp_association *asoc, 5537 const union sctp_subtype type, 5538 void *arg, 5539 struct sctp_cmd_seq *commands) 5540 { 5541 struct sctp_chunk *chunk = arg; 5542 5543 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5544 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5545 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5546 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5547 return SCTP_DISPOSITION_CONSUME; 5548 } 5549 5550 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5551 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5552 const struct sctp_endpoint *ep, 5553 const struct sctp_association *asoc, 5554 const union sctp_subtype type, 5555 void *arg, 5556 struct sctp_cmd_seq *commands) 5557 { 5558 struct sctp_chunk *chunk = arg; 5559 5560 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5561 return SCTP_DISPOSITION_CONSUME; 5562 } 5563 5564 /* 5565 * Ignore the primitive event 5566 * 5567 * The return value is the disposition of the primitive. 5568 */ 5569 enum sctp_disposition sctp_sf_ignore_primitive( 5570 struct net *net, 5571 const struct sctp_endpoint *ep, 5572 const struct sctp_association *asoc, 5573 const union sctp_subtype type, 5574 void *arg, 5575 struct sctp_cmd_seq *commands) 5576 { 5577 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5578 type.primitive); 5579 5580 return SCTP_DISPOSITION_DISCARD; 5581 } 5582 5583 /*************************************************************************** 5584 * These are the state functions for the OTHER events. 5585 ***************************************************************************/ 5586 5587 /* 5588 * When the SCTP stack has no more user data to send or retransmit, this 5589 * notification is given to the user. Also, at the time when a user app 5590 * subscribes to this event, if there is no data to be sent or 5591 * retransmit, the stack will immediately send up this notification. 5592 */ 5593 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5594 struct net *net, 5595 const struct sctp_endpoint *ep, 5596 const struct sctp_association *asoc, 5597 const union sctp_subtype type, 5598 void *arg, 5599 struct sctp_cmd_seq *commands) 5600 { 5601 struct sctp_ulpevent *event; 5602 5603 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5604 if (!event) 5605 return SCTP_DISPOSITION_NOMEM; 5606 5607 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5608 5609 return SCTP_DISPOSITION_CONSUME; 5610 } 5611 5612 /* 5613 * Start the shutdown negotiation. 5614 * 5615 * From Section 9.2: 5616 * Once all its outstanding data has been acknowledged, the endpoint 5617 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5618 * TSN Ack field the last sequential TSN it has received from the peer. 5619 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5620 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5621 * with the updated last sequential TSN received from its peer. 5622 * 5623 * The return value is the disposition. 5624 */ 5625 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5626 struct net *net, 5627 const struct sctp_endpoint *ep, 5628 const struct sctp_association *asoc, 5629 const union sctp_subtype type, 5630 void *arg, 5631 struct sctp_cmd_seq *commands) 5632 { 5633 struct sctp_chunk *reply; 5634 5635 /* Once all its outstanding data has been acknowledged, the 5636 * endpoint shall send a SHUTDOWN chunk to its peer including 5637 * in the Cumulative TSN Ack field the last sequential TSN it 5638 * has received from the peer. 5639 */ 5640 reply = sctp_make_shutdown(asoc, arg); 5641 if (!reply) 5642 goto nomem; 5643 5644 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5645 * T2-shutdown timer. 5646 */ 5647 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5648 5649 /* It shall then start the T2-shutdown timer */ 5650 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5651 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5652 5653 /* RFC 4960 Section 9.2 5654 * The sender of the SHUTDOWN MAY also start an overall guard timer 5655 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5656 */ 5657 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5658 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5659 5660 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5661 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5662 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5663 5664 /* and enter the SHUTDOWN-SENT state. */ 5665 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5666 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5667 5668 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5669 * 5670 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5671 * or SHUTDOWN-ACK. 5672 */ 5673 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5674 5675 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5676 5677 return SCTP_DISPOSITION_CONSUME; 5678 5679 nomem: 5680 return SCTP_DISPOSITION_NOMEM; 5681 } 5682 5683 /* 5684 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5685 * 5686 * From Section 9.2: 5687 * 5688 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5689 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5690 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5691 * endpoint must re-send the SHUTDOWN ACK. 5692 * 5693 * The return value is the disposition. 5694 */ 5695 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5696 struct net *net, 5697 const struct sctp_endpoint *ep, 5698 const struct sctp_association *asoc, 5699 const union sctp_subtype type, 5700 void *arg, 5701 struct sctp_cmd_seq *commands) 5702 { 5703 struct sctp_chunk *chunk = arg; 5704 struct sctp_chunk *reply; 5705 5706 /* There are 2 ways of getting here: 5707 * 1) called in response to a SHUTDOWN chunk 5708 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5709 * 5710 * For the case (2), the arg parameter is set to NULL. We need 5711 * to check that we have a chunk before accessing it's fields. 5712 */ 5713 if (chunk) { 5714 if (!sctp_vtag_verify(chunk, asoc)) 5715 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5716 commands); 5717 5718 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5719 if (!sctp_chunk_length_valid( 5720 chunk, sizeof(struct sctp_shutdown_chunk))) 5721 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5722 arg, commands); 5723 } 5724 5725 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5726 * shall send a SHUTDOWN ACK ... 5727 */ 5728 reply = sctp_make_shutdown_ack(asoc, chunk); 5729 if (!reply) 5730 goto nomem; 5731 5732 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5733 * the T2-shutdown timer. 5734 */ 5735 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5736 5737 /* and start/restart a T2-shutdown timer of its own, */ 5738 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5739 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5740 5741 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5742 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5743 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5744 5745 /* Enter the SHUTDOWN-ACK-SENT state. */ 5746 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5747 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5748 5749 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5750 * 5751 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5752 * or SHUTDOWN-ACK. 5753 */ 5754 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5755 5756 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5757 5758 return SCTP_DISPOSITION_CONSUME; 5759 5760 nomem: 5761 return SCTP_DISPOSITION_NOMEM; 5762 } 5763 5764 /* 5765 * Ignore the event defined as other 5766 * 5767 * The return value is the disposition of the event. 5768 */ 5769 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5770 const struct sctp_endpoint *ep, 5771 const struct sctp_association *asoc, 5772 const union sctp_subtype type, 5773 void *arg, 5774 struct sctp_cmd_seq *commands) 5775 { 5776 pr_debug("%s: the event other type:%d is ignored\n", 5777 __func__, type.other); 5778 5779 return SCTP_DISPOSITION_DISCARD; 5780 } 5781 5782 /************************************************************ 5783 * These are the state functions for handling timeout events. 5784 ************************************************************/ 5785 5786 /* 5787 * RTX Timeout 5788 * 5789 * Section: 6.3.3 Handle T3-rtx Expiration 5790 * 5791 * Whenever the retransmission timer T3-rtx expires for a destination 5792 * address, do the following: 5793 * [See below] 5794 * 5795 * The return value is the disposition of the chunk. 5796 */ 5797 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5798 const struct sctp_endpoint *ep, 5799 const struct sctp_association *asoc, 5800 const union sctp_subtype type, 5801 void *arg, 5802 struct sctp_cmd_seq *commands) 5803 { 5804 struct sctp_transport *transport = arg; 5805 5806 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5807 5808 if (asoc->overall_error_count >= asoc->max_retrans) { 5809 if (asoc->peer.zero_window_announced && 5810 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5811 /* 5812 * We are here likely because the receiver had its rwnd 5813 * closed for a while and we have not been able to 5814 * transmit the locally queued data within the maximum 5815 * retransmission attempts limit. Start the T5 5816 * shutdown guard timer to give the receiver one last 5817 * chance and some additional time to recover before 5818 * aborting. 5819 */ 5820 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5821 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5822 } else { 5823 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5824 SCTP_ERROR(ETIMEDOUT)); 5825 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5826 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5827 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5828 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5829 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5830 return SCTP_DISPOSITION_DELETE_TCB; 5831 } 5832 } 5833 5834 /* E1) For the destination address for which the timer 5835 * expires, adjust its ssthresh with rules defined in Section 5836 * 7.2.3 and set the cwnd <- MTU. 5837 */ 5838 5839 /* E2) For the destination address for which the timer 5840 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5841 * maximum value discussed in rule C7 above (RTO.max) may be 5842 * used to provide an upper bound to this doubling operation. 5843 */ 5844 5845 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5846 * outstanding DATA chunks for the address for which the 5847 * T3-rtx has expired will fit into a single packet, subject 5848 * to the MTU constraint for the path corresponding to the 5849 * destination transport address to which the retransmission 5850 * is being sent (this may be different from the address for 5851 * which the timer expires [see Section 6.4]). Call this 5852 * value K. Bundle and retransmit those K DATA chunks in a 5853 * single packet to the destination endpoint. 5854 * 5855 * Note: Any DATA chunks that were sent to the address for 5856 * which the T3-rtx timer expired but did not fit in one MTU 5857 * (rule E3 above), should be marked for retransmission and 5858 * sent as soon as cwnd allows (normally when a SACK arrives). 5859 */ 5860 5861 /* Do some failure management (Section 8.2). */ 5862 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5863 5864 /* NB: Rules E4 and F1 are implicit in R1. */ 5865 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5866 5867 return SCTP_DISPOSITION_CONSUME; 5868 } 5869 5870 /* 5871 * Generate delayed SACK on timeout 5872 * 5873 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5874 * 5875 * The guidelines on delayed acknowledgement algorithm specified in 5876 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5877 * acknowledgement SHOULD be generated for at least every second packet 5878 * (not every second DATA chunk) received, and SHOULD be generated 5879 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5880 * some situations it may be beneficial for an SCTP transmitter to be 5881 * more conservative than the algorithms detailed in this document 5882 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5883 * the following algorithms allow. 5884 */ 5885 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5886 const struct sctp_endpoint *ep, 5887 const struct sctp_association *asoc, 5888 const union sctp_subtype type, 5889 void *arg, 5890 struct sctp_cmd_seq *commands) 5891 { 5892 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5893 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5894 return SCTP_DISPOSITION_CONSUME; 5895 } 5896 5897 /* 5898 * sctp_sf_t1_init_timer_expire 5899 * 5900 * Section: 4 Note: 2 5901 * Verification Tag: 5902 * Inputs 5903 * (endpoint, asoc) 5904 * 5905 * RFC 2960 Section 4 Notes 5906 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5907 * and re-start the T1-init timer without changing state. This MUST 5908 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5909 * endpoint MUST abort the initialization process and report the 5910 * error to SCTP user. 5911 * 5912 * Outputs 5913 * (timers, events) 5914 * 5915 */ 5916 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5917 struct net *net, 5918 const struct sctp_endpoint *ep, 5919 const struct sctp_association *asoc, 5920 const union sctp_subtype type, 5921 void *arg, 5922 struct sctp_cmd_seq *commands) 5923 { 5924 int attempts = asoc->init_err_counter + 1; 5925 struct sctp_chunk *repl = NULL; 5926 struct sctp_bind_addr *bp; 5927 5928 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5929 5930 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5931 5932 if (attempts <= asoc->max_init_attempts) { 5933 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5934 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5935 if (!repl) 5936 return SCTP_DISPOSITION_NOMEM; 5937 5938 /* Choose transport for INIT. */ 5939 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5940 SCTP_CHUNK(repl)); 5941 5942 /* Issue a sideeffect to do the needed accounting. */ 5943 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5944 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5945 5946 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5947 } else { 5948 pr_debug("%s: giving up on INIT, attempts:%d " 5949 "max_init_attempts:%d\n", __func__, attempts, 5950 asoc->max_init_attempts); 5951 5952 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5953 SCTP_ERROR(ETIMEDOUT)); 5954 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5955 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5956 return SCTP_DISPOSITION_DELETE_TCB; 5957 } 5958 5959 return SCTP_DISPOSITION_CONSUME; 5960 } 5961 5962 /* 5963 * sctp_sf_t1_cookie_timer_expire 5964 * 5965 * Section: 4 Note: 2 5966 * Verification Tag: 5967 * Inputs 5968 * (endpoint, asoc) 5969 * 5970 * RFC 2960 Section 4 Notes 5971 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5972 * COOKIE ECHO and re-start the T1-cookie timer without changing 5973 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5974 * After that, the endpoint MUST abort the initialization process and 5975 * report the error to SCTP user. 5976 * 5977 * Outputs 5978 * (timers, events) 5979 * 5980 */ 5981 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5982 struct net *net, 5983 const struct sctp_endpoint *ep, 5984 const struct sctp_association *asoc, 5985 const union sctp_subtype type, 5986 void *arg, 5987 struct sctp_cmd_seq *commands) 5988 { 5989 int attempts = asoc->init_err_counter + 1; 5990 struct sctp_chunk *repl = NULL; 5991 5992 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5993 5994 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5995 5996 if (attempts <= asoc->max_init_attempts) { 5997 repl = sctp_make_cookie_echo(asoc, NULL); 5998 if (!repl) 5999 return SCTP_DISPOSITION_NOMEM; 6000 6001 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 6002 SCTP_CHUNK(repl)); 6003 /* Issue a sideeffect to do the needed accounting. */ 6004 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 6005 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 6006 6007 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 6008 } else { 6009 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6010 SCTP_ERROR(ETIMEDOUT)); 6011 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 6012 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6013 return SCTP_DISPOSITION_DELETE_TCB; 6014 } 6015 6016 return SCTP_DISPOSITION_CONSUME; 6017 } 6018 6019 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 6020 * with the updated last sequential TSN received from its peer. 6021 * 6022 * An endpoint should limit the number of retransmission of the 6023 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 6024 * If this threshold is exceeded the endpoint should destroy the TCB and 6025 * MUST report the peer endpoint unreachable to the upper layer (and 6026 * thus the association enters the CLOSED state). The reception of any 6027 * packet from its peer (i.e. as the peer sends all of its queued DATA 6028 * chunks) should clear the endpoint's retransmission count and restart 6029 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 6030 * all of its queued DATA chunks that have not yet been sent. 6031 */ 6032 enum sctp_disposition sctp_sf_t2_timer_expire( 6033 struct net *net, 6034 const struct sctp_endpoint *ep, 6035 const struct sctp_association *asoc, 6036 const union sctp_subtype type, 6037 void *arg, 6038 struct sctp_cmd_seq *commands) 6039 { 6040 struct sctp_chunk *reply = NULL; 6041 6042 pr_debug("%s: timer T2 expired\n", __func__); 6043 6044 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 6045 6046 ((struct sctp_association *)asoc)->shutdown_retries++; 6047 6048 if (asoc->overall_error_count >= asoc->max_retrans) { 6049 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6050 SCTP_ERROR(ETIMEDOUT)); 6051 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 6052 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6053 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6054 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6055 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6056 return SCTP_DISPOSITION_DELETE_TCB; 6057 } 6058 6059 switch (asoc->state) { 6060 case SCTP_STATE_SHUTDOWN_SENT: 6061 reply = sctp_make_shutdown(asoc, NULL); 6062 break; 6063 6064 case SCTP_STATE_SHUTDOWN_ACK_SENT: 6065 reply = sctp_make_shutdown_ack(asoc, NULL); 6066 break; 6067 6068 default: 6069 BUG(); 6070 break; 6071 } 6072 6073 if (!reply) 6074 goto nomem; 6075 6076 /* Do some failure management (Section 8.2). 6077 * If we remove the transport an SHUTDOWN was last sent to, don't 6078 * do failure management. 6079 */ 6080 if (asoc->shutdown_last_sent_to) 6081 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6082 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 6083 6084 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 6085 * the T2-shutdown timer. 6086 */ 6087 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6088 6089 /* Restart the T2-shutdown timer. */ 6090 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6091 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6092 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6093 return SCTP_DISPOSITION_CONSUME; 6094 6095 nomem: 6096 return SCTP_DISPOSITION_NOMEM; 6097 } 6098 6099 /* 6100 * ADDIP Section 4.1 ASCONF Chunk Procedures 6101 * If the T4 RTO timer expires the endpoint should do B1 to B5 6102 */ 6103 enum sctp_disposition sctp_sf_t4_timer_expire( 6104 struct net *net, 6105 const struct sctp_endpoint *ep, 6106 const struct sctp_association *asoc, 6107 const union sctp_subtype type, 6108 void *arg, 6109 struct sctp_cmd_seq *commands) 6110 { 6111 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6112 struct sctp_transport *transport = chunk->transport; 6113 6114 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6115 6116 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6117 * detection on the appropriate destination address as defined in 6118 * RFC2960 [5] section 8.1 and 8.2. 6119 */ 6120 if (transport) 6121 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6122 SCTP_TRANSPORT(transport)); 6123 6124 /* Reconfig T4 timer and transport. */ 6125 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6126 6127 /* ADDIP 4.1 B2) Increment the association error counters and perform 6128 * endpoint failure detection on the association as defined in 6129 * RFC2960 [5] section 8.1 and 8.2. 6130 * association error counter is incremented in SCTP_CMD_STRIKE. 6131 */ 6132 if (asoc->overall_error_count >= asoc->max_retrans) { 6133 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6134 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6135 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6136 SCTP_ERROR(ETIMEDOUT)); 6137 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6138 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6139 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6140 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6141 return SCTP_DISPOSITION_ABORT; 6142 } 6143 6144 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6145 * the ASCONF chunk was sent by doubling the RTO timer value. 6146 * This is done in SCTP_CMD_STRIKE. 6147 */ 6148 6149 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6150 * choose an alternate destination address (please refer to RFC2960 6151 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6152 * chunk, it MUST be the same (including its serial number) as the last 6153 * ASCONF sent. 6154 */ 6155 sctp_chunk_hold(asoc->addip_last_asconf); 6156 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6157 SCTP_CHUNK(asoc->addip_last_asconf)); 6158 6159 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6160 * destination is selected, then the RTO used will be that of the new 6161 * destination address. 6162 */ 6163 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6164 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6165 6166 return SCTP_DISPOSITION_CONSUME; 6167 } 6168 6169 /* sctpimpguide-05 Section 2.12.2 6170 * The sender of the SHUTDOWN MAY also start an overall guard timer 6171 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6172 * At the expiration of this timer the sender SHOULD abort the association 6173 * by sending an ABORT chunk. 6174 */ 6175 enum sctp_disposition sctp_sf_t5_timer_expire( 6176 struct net *net, 6177 const struct sctp_endpoint *ep, 6178 const struct sctp_association *asoc, 6179 const union sctp_subtype type, 6180 void *arg, 6181 struct sctp_cmd_seq *commands) 6182 { 6183 struct sctp_chunk *reply = NULL; 6184 6185 pr_debug("%s: timer T5 expired\n", __func__); 6186 6187 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6188 6189 reply = sctp_make_abort(asoc, NULL, 0); 6190 if (!reply) 6191 goto nomem; 6192 6193 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6194 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6195 SCTP_ERROR(ETIMEDOUT)); 6196 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6197 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6198 6199 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6200 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6201 6202 return SCTP_DISPOSITION_DELETE_TCB; 6203 nomem: 6204 return SCTP_DISPOSITION_NOMEM; 6205 } 6206 6207 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6208 * the association is automatically closed by starting the shutdown process. 6209 * The work that needs to be done is same as when SHUTDOWN is initiated by 6210 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6211 */ 6212 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6213 struct net *net, 6214 const struct sctp_endpoint *ep, 6215 const struct sctp_association *asoc, 6216 const union sctp_subtype type, 6217 void *arg, 6218 struct sctp_cmd_seq *commands) 6219 { 6220 enum sctp_disposition disposition; 6221 6222 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6223 6224 /* From 9.2 Shutdown of an Association 6225 * Upon receipt of the SHUTDOWN primitive from its upper 6226 * layer, the endpoint enters SHUTDOWN-PENDING state and 6227 * remains there until all outstanding data has been 6228 * acknowledged by its peer. The endpoint accepts no new data 6229 * from its upper layer, but retransmits data to the far end 6230 * if necessary to fill gaps. 6231 */ 6232 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6233 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6234 6235 disposition = SCTP_DISPOSITION_CONSUME; 6236 if (sctp_outq_is_empty(&asoc->outqueue)) { 6237 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6238 NULL, commands); 6239 } 6240 6241 return disposition; 6242 } 6243 6244 /***************************************************************************** 6245 * These are sa state functions which could apply to all types of events. 6246 ****************************************************************************/ 6247 6248 /* 6249 * This table entry is not implemented. 6250 * 6251 * Inputs 6252 * (endpoint, asoc, chunk) 6253 * 6254 * The return value is the disposition of the chunk. 6255 */ 6256 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6257 const struct sctp_endpoint *ep, 6258 const struct sctp_association *asoc, 6259 const union sctp_subtype type, 6260 void *arg, struct sctp_cmd_seq *commands) 6261 { 6262 return SCTP_DISPOSITION_NOT_IMPL; 6263 } 6264 6265 /* 6266 * This table entry represents a bug. 6267 * 6268 * Inputs 6269 * (endpoint, asoc, chunk) 6270 * 6271 * The return value is the disposition of the chunk. 6272 */ 6273 enum sctp_disposition sctp_sf_bug(struct net *net, 6274 const struct sctp_endpoint *ep, 6275 const struct sctp_association *asoc, 6276 const union sctp_subtype type, 6277 void *arg, struct sctp_cmd_seq *commands) 6278 { 6279 return SCTP_DISPOSITION_BUG; 6280 } 6281 6282 /* 6283 * This table entry represents the firing of a timer in the wrong state. 6284 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6285 * when the association is in the wrong state. This event should 6286 * be ignored, so as to prevent any rearming of the timer. 6287 * 6288 * Inputs 6289 * (endpoint, asoc, chunk) 6290 * 6291 * The return value is the disposition of the chunk. 6292 */ 6293 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6294 const struct sctp_endpoint *ep, 6295 const struct sctp_association *asoc, 6296 const union sctp_subtype type, 6297 void *arg, 6298 struct sctp_cmd_seq *commands) 6299 { 6300 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6301 6302 return SCTP_DISPOSITION_CONSUME; 6303 } 6304 6305 /******************************************************************** 6306 * 2nd Level Abstractions 6307 ********************************************************************/ 6308 6309 /* Pull the SACK chunk based on the SACK header. */ 6310 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6311 { 6312 struct sctp_sackhdr *sack; 6313 __u16 num_dup_tsns; 6314 unsigned int len; 6315 __u16 num_blocks; 6316 6317 /* Protect ourselves from reading too far into 6318 * the skb from a bogus sender. 6319 */ 6320 sack = (struct sctp_sackhdr *) chunk->skb->data; 6321 6322 num_blocks = ntohs(sack->num_gap_ack_blocks); 6323 num_dup_tsns = ntohs(sack->num_dup_tsns); 6324 len = sizeof(struct sctp_sackhdr); 6325 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6326 if (len > chunk->skb->len) 6327 return NULL; 6328 6329 skb_pull(chunk->skb, len); 6330 6331 return sack; 6332 } 6333 6334 /* Create an ABORT packet to be sent as a response, with the specified 6335 * error causes. 6336 */ 6337 static struct sctp_packet *sctp_abort_pkt_new( 6338 struct net *net, 6339 const struct sctp_endpoint *ep, 6340 const struct sctp_association *asoc, 6341 struct sctp_chunk *chunk, 6342 const void *payload, size_t paylen) 6343 { 6344 struct sctp_packet *packet; 6345 struct sctp_chunk *abort; 6346 6347 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6348 6349 if (packet) { 6350 /* Make an ABORT. 6351 * The T bit will be set if the asoc is NULL. 6352 */ 6353 abort = sctp_make_abort(asoc, chunk, paylen); 6354 if (!abort) { 6355 sctp_ootb_pkt_free(packet); 6356 return NULL; 6357 } 6358 6359 /* Reflect vtag if T-Bit is set */ 6360 if (sctp_test_T_bit(abort)) 6361 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6362 6363 /* Add specified error causes, i.e., payload, to the 6364 * end of the chunk. 6365 */ 6366 sctp_addto_chunk(abort, paylen, payload); 6367 6368 /* Set the skb to the belonging sock for accounting. */ 6369 abort->skb->sk = ep->base.sk; 6370 6371 sctp_packet_append_chunk(packet, abort); 6372 6373 } 6374 6375 return packet; 6376 } 6377 6378 /* Allocate a packet for responding in the OOTB conditions. */ 6379 static struct sctp_packet *sctp_ootb_pkt_new( 6380 struct net *net, 6381 const struct sctp_association *asoc, 6382 const struct sctp_chunk *chunk) 6383 { 6384 struct sctp_transport *transport; 6385 struct sctp_packet *packet; 6386 __u16 sport, dport; 6387 __u32 vtag; 6388 6389 /* Get the source and destination port from the inbound packet. */ 6390 sport = ntohs(chunk->sctp_hdr->dest); 6391 dport = ntohs(chunk->sctp_hdr->source); 6392 6393 /* The V-tag is going to be the same as the inbound packet if no 6394 * association exists, otherwise, use the peer's vtag. 6395 */ 6396 if (asoc) { 6397 /* Special case the INIT-ACK as there is no peer's vtag 6398 * yet. 6399 */ 6400 switch (chunk->chunk_hdr->type) { 6401 case SCTP_CID_INIT: 6402 case SCTP_CID_INIT_ACK: 6403 { 6404 struct sctp_initack_chunk *initack; 6405 6406 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6407 vtag = ntohl(initack->init_hdr.init_tag); 6408 break; 6409 } 6410 default: 6411 vtag = asoc->peer.i.init_tag; 6412 break; 6413 } 6414 } else { 6415 /* Special case the INIT and stale COOKIE_ECHO as there is no 6416 * vtag yet. 6417 */ 6418 switch (chunk->chunk_hdr->type) { 6419 case SCTP_CID_INIT: 6420 { 6421 struct sctp_init_chunk *init; 6422 6423 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6424 vtag = ntohl(init->init_hdr.init_tag); 6425 break; 6426 } 6427 default: 6428 vtag = ntohl(chunk->sctp_hdr->vtag); 6429 break; 6430 } 6431 } 6432 6433 /* Make a transport for the bucket, Eliza... */ 6434 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6435 if (!transport) 6436 goto nomem; 6437 6438 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6439 6440 /* Cache a route for the transport with the chunk's destination as 6441 * the source address. 6442 */ 6443 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6444 sctp_sk(net->sctp.ctl_sock)); 6445 6446 packet = &transport->packet; 6447 sctp_packet_init(packet, transport, sport, dport); 6448 sctp_packet_config(packet, vtag, 0); 6449 6450 return packet; 6451 6452 nomem: 6453 return NULL; 6454 } 6455 6456 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6457 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6458 { 6459 sctp_transport_free(packet->transport); 6460 } 6461 6462 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6463 static void sctp_send_stale_cookie_err(struct net *net, 6464 const struct sctp_endpoint *ep, 6465 const struct sctp_association *asoc, 6466 const struct sctp_chunk *chunk, 6467 struct sctp_cmd_seq *commands, 6468 struct sctp_chunk *err_chunk) 6469 { 6470 struct sctp_packet *packet; 6471 6472 if (err_chunk) { 6473 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6474 if (packet) { 6475 struct sctp_signed_cookie *cookie; 6476 6477 /* Override the OOTB vtag from the cookie. */ 6478 cookie = chunk->subh.cookie_hdr; 6479 packet->vtag = cookie->c.peer_vtag; 6480 6481 /* Set the skb to the belonging sock for accounting. */ 6482 err_chunk->skb->sk = ep->base.sk; 6483 sctp_packet_append_chunk(packet, err_chunk); 6484 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6485 SCTP_PACKET(packet)); 6486 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6487 } else 6488 sctp_chunk_free (err_chunk); 6489 } 6490 } 6491 6492 6493 /* Process a data chunk */ 6494 static int sctp_eat_data(const struct sctp_association *asoc, 6495 struct sctp_chunk *chunk, 6496 struct sctp_cmd_seq *commands) 6497 { 6498 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6499 struct sock *sk = asoc->base.sk; 6500 struct net *net = sock_net(sk); 6501 struct sctp_datahdr *data_hdr; 6502 struct sctp_chunk *err; 6503 enum sctp_verb deliver; 6504 size_t datalen; 6505 __u32 tsn; 6506 int tmp; 6507 6508 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6509 chunk->subh.data_hdr = data_hdr; 6510 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6511 6512 tsn = ntohl(data_hdr->tsn); 6513 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6514 6515 /* ASSERT: Now skb->data is really the user data. */ 6516 6517 /* Process ECN based congestion. 6518 * 6519 * Since the chunk structure is reused for all chunks within 6520 * a packet, we use ecn_ce_done to track if we've already 6521 * done CE processing for this packet. 6522 * 6523 * We need to do ECN processing even if we plan to discard the 6524 * chunk later. 6525 */ 6526 6527 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6528 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6529 chunk->ecn_ce_done = 1; 6530 6531 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6532 /* Do real work as side effect. */ 6533 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6534 SCTP_U32(tsn)); 6535 } 6536 } 6537 6538 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6539 if (tmp < 0) { 6540 /* The TSN is too high--silently discard the chunk and 6541 * count on it getting retransmitted later. 6542 */ 6543 if (chunk->asoc) 6544 chunk->asoc->stats.outofseqtsns++; 6545 return SCTP_IERROR_HIGH_TSN; 6546 } else if (tmp > 0) { 6547 /* This is a duplicate. Record it. */ 6548 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6549 return SCTP_IERROR_DUP_TSN; 6550 } 6551 6552 /* This is a new TSN. */ 6553 6554 /* Discard if there is no room in the receive window. 6555 * Actually, allow a little bit of overflow (up to a MTU). 6556 */ 6557 datalen = ntohs(chunk->chunk_hdr->length); 6558 datalen -= sctp_datachk_len(&asoc->stream); 6559 6560 deliver = SCTP_CMD_CHUNK_ULP; 6561 6562 /* Think about partial delivery. */ 6563 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6564 6565 /* Even if we don't accept this chunk there is 6566 * memory pressure. 6567 */ 6568 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6569 } 6570 6571 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6572 * seems a bit troublesome in that frag_point varies based on 6573 * PMTU. In cases, such as loopback, this might be a rather 6574 * large spill over. 6575 */ 6576 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6577 (datalen > asoc->rwnd + asoc->frag_point))) { 6578 6579 /* If this is the next TSN, consider reneging to make 6580 * room. Note: Playing nice with a confused sender. A 6581 * malicious sender can still eat up all our buffer 6582 * space and in the future we may want to detect and 6583 * do more drastic reneging. 6584 */ 6585 if (sctp_tsnmap_has_gap(map) && 6586 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6587 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6588 deliver = SCTP_CMD_RENEGE; 6589 } else { 6590 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6591 __func__, tsn, datalen, asoc->rwnd); 6592 6593 return SCTP_IERROR_IGNORE_TSN; 6594 } 6595 } 6596 6597 /* 6598 * Also try to renege to limit our memory usage in the event that 6599 * we are under memory pressure 6600 * If we can't renege, don't worry about it, the sk_rmem_schedule 6601 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6602 * memory usage too much 6603 */ 6604 if (sk_under_memory_pressure(sk)) { 6605 if (sctp_tsnmap_has_gap(map) && 6606 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6607 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6608 __func__, tsn); 6609 deliver = SCTP_CMD_RENEGE; 6610 } 6611 } 6612 6613 /* 6614 * Section 3.3.10.9 No User Data (9) 6615 * 6616 * Cause of error 6617 * --------------- 6618 * No User Data: This error cause is returned to the originator of a 6619 * DATA chunk if a received DATA chunk has no user data. 6620 */ 6621 if (unlikely(0 == datalen)) { 6622 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6623 if (err) { 6624 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6625 SCTP_CHUNK(err)); 6626 } 6627 /* We are going to ABORT, so we might as well stop 6628 * processing the rest of the chunks in the packet. 6629 */ 6630 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6631 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6632 SCTP_ERROR(ECONNABORTED)); 6633 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6634 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6635 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6636 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6637 return SCTP_IERROR_NO_DATA; 6638 } 6639 6640 chunk->data_accepted = 1; 6641 6642 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6643 * if we renege and the chunk arrives again. 6644 */ 6645 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6646 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6647 if (chunk->asoc) 6648 chunk->asoc->stats.iuodchunks++; 6649 } else { 6650 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6651 if (chunk->asoc) 6652 chunk->asoc->stats.iodchunks++; 6653 } 6654 6655 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6656 * 6657 * If an endpoint receive a DATA chunk with an invalid stream 6658 * identifier, it shall acknowledge the reception of the DATA chunk 6659 * following the normal procedure, immediately send an ERROR chunk 6660 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6661 * and discard the DATA chunk. 6662 */ 6663 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6664 /* Mark tsn as received even though we drop it */ 6665 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6666 6667 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6668 &data_hdr->stream, 6669 sizeof(data_hdr->stream), 6670 sizeof(u16)); 6671 if (err) 6672 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6673 SCTP_CHUNK(err)); 6674 return SCTP_IERROR_BAD_STREAM; 6675 } 6676 6677 /* Check to see if the SSN is possible for this TSN. 6678 * The biggest gap we can record is 4K wide. Since SSNs wrap 6679 * at an unsigned short, there is no way that an SSN can 6680 * wrap and for a valid TSN. We can simply check if the current 6681 * SSN is smaller then the next expected one. If it is, it wrapped 6682 * and is invalid. 6683 */ 6684 if (!asoc->stream.si->validate_data(chunk)) 6685 return SCTP_IERROR_PROTO_VIOLATION; 6686 6687 /* Send the data up to the user. Note: Schedule the 6688 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6689 * chunk needs the updated rwnd. 6690 */ 6691 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6692 6693 return SCTP_IERROR_NO_ERROR; 6694 } 6695