1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999-2000 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * Copyright (c) 2001-2002 Intel Corp. 7 * Copyright (c) 2002 Nokia Corp. 8 * 9 * This is part of the SCTP Linux Kernel Implementation. 10 * 11 * These are the state functions for the state machine. 12 * 13 * Please send any bug reports or fixes you make to the 14 * email address(es): 15 * lksctp developers <linux-sctp@vger.kernel.org> 16 * 17 * Written or modified by: 18 * La Monte H.P. Yarroll <piggy@acm.org> 19 * Karl Knutson <karl@athena.chicago.il.us> 20 * Mathew Kotowsky <kotowsky@sctp.org> 21 * Sridhar Samudrala <samudrala@us.ibm.com> 22 * Jon Grimm <jgrimm@us.ibm.com> 23 * Hui Huang <hui.huang@nokia.com> 24 * Dajiang Zhang <dajiang.zhang@nokia.com> 25 * Daisy Chang <daisyc@us.ibm.com> 26 * Ardelle Fan <ardelle.fan@intel.com> 27 * Ryan Layer <rmlayer@us.ibm.com> 28 * Kevin Gao <kevin.gao@intel.com> 29 */ 30 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33 #include <linux/types.h> 34 #include <linux/kernel.h> 35 #include <linux/ip.h> 36 #include <linux/ipv6.h> 37 #include <linux/net.h> 38 #include <linux/inet.h> 39 #include <linux/slab.h> 40 #include <net/sock.h> 41 #include <net/inet_ecn.h> 42 #include <linux/skbuff.h> 43 #include <net/sctp/sctp.h> 44 #include <net/sctp/sm.h> 45 #include <net/sctp/structs.h> 46 47 #define CREATE_TRACE_POINTS 48 #include <trace/events/sctp.h> 49 50 static struct sctp_packet *sctp_abort_pkt_new( 51 struct net *net, 52 const struct sctp_endpoint *ep, 53 const struct sctp_association *asoc, 54 struct sctp_chunk *chunk, 55 const void *payload, size_t paylen); 56 static int sctp_eat_data(const struct sctp_association *asoc, 57 struct sctp_chunk *chunk, 58 struct sctp_cmd_seq *commands); 59 static struct sctp_packet *sctp_ootb_pkt_new( 60 struct net *net, 61 const struct sctp_association *asoc, 62 const struct sctp_chunk *chunk); 63 static void sctp_send_stale_cookie_err(struct net *net, 64 const struct sctp_endpoint *ep, 65 const struct sctp_association *asoc, 66 const struct sctp_chunk *chunk, 67 struct sctp_cmd_seq *commands, 68 struct sctp_chunk *err_chunk); 69 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 70 struct net *net, 71 const struct sctp_endpoint *ep, 72 const struct sctp_association *asoc, 73 const union sctp_subtype type, 74 void *arg, 75 struct sctp_cmd_seq *commands); 76 static enum sctp_disposition sctp_sf_shut_8_4_5( 77 struct net *net, 78 const struct sctp_endpoint *ep, 79 const struct sctp_association *asoc, 80 const union sctp_subtype type, 81 void *arg, 82 struct sctp_cmd_seq *commands); 83 static enum sctp_disposition sctp_sf_tabort_8_4_8( 84 struct net *net, 85 const struct sctp_endpoint *ep, 86 const struct sctp_association *asoc, 87 const union sctp_subtype type, 88 void *arg, 89 struct sctp_cmd_seq *commands); 90 static enum sctp_disposition sctp_sf_new_encap_port( 91 struct net *net, 92 const struct sctp_endpoint *ep, 93 const struct sctp_association *asoc, 94 const union sctp_subtype type, 95 void *arg, 96 struct sctp_cmd_seq *commands); 97 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 98 99 static enum sctp_disposition sctp_stop_t1_and_abort( 100 struct net *net, 101 struct sctp_cmd_seq *commands, 102 __be16 error, int sk_err, 103 const struct sctp_association *asoc, 104 struct sctp_transport *transport); 105 106 static enum sctp_disposition sctp_sf_abort_violation( 107 struct net *net, 108 const struct sctp_endpoint *ep, 109 const struct sctp_association *asoc, 110 void *arg, 111 struct sctp_cmd_seq *commands, 112 const __u8 *payload, 113 const size_t paylen); 114 115 static enum sctp_disposition sctp_sf_violation_chunklen( 116 struct net *net, 117 const struct sctp_endpoint *ep, 118 const struct sctp_association *asoc, 119 const union sctp_subtype type, 120 void *arg, 121 struct sctp_cmd_seq *commands); 122 123 static enum sctp_disposition sctp_sf_violation_paramlen( 124 struct net *net, 125 const struct sctp_endpoint *ep, 126 const struct sctp_association *asoc, 127 const union sctp_subtype type, 128 void *arg, void *ext, 129 struct sctp_cmd_seq *commands); 130 131 static enum sctp_disposition sctp_sf_violation_ctsn( 132 struct net *net, 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const union sctp_subtype type, 136 void *arg, 137 struct sctp_cmd_seq *commands); 138 139 static enum sctp_disposition sctp_sf_violation_chunk( 140 struct net *net, 141 const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const union sctp_subtype type, 144 void *arg, 145 struct sctp_cmd_seq *commands); 146 147 static enum sctp_ierror sctp_sf_authenticate( 148 const struct sctp_association *asoc, 149 struct sctp_chunk *chunk); 150 151 static enum sctp_disposition __sctp_sf_do_9_1_abort( 152 struct net *net, 153 const struct sctp_endpoint *ep, 154 const struct sctp_association *asoc, 155 const union sctp_subtype type, 156 void *arg, 157 struct sctp_cmd_seq *commands); 158 159 static enum sctp_disposition 160 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 161 const struct sctp_association *asoc, 162 const union sctp_subtype type, void *arg, 163 struct sctp_cmd_seq *commands); 164 165 /* Small helper function that checks if the chunk length 166 * is of the appropriate length. The 'required_length' argument 167 * is set to be the size of a specific chunk we are testing. 168 * Return Values: true = Valid length 169 * false = Invalid length 170 * 171 */ 172 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 173 __u16 required_length) 174 { 175 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 176 177 /* Previously already marked? */ 178 if (unlikely(chunk->pdiscard)) 179 return false; 180 if (unlikely(chunk_length < required_length)) 181 return false; 182 183 return true; 184 } 185 186 /* Check for format error in an ABORT chunk */ 187 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk) 188 { 189 struct sctp_errhdr *err; 190 191 sctp_walk_errors(err, chunk->chunk_hdr); 192 193 return (void *)err == (void *)chunk->chunk_end; 194 } 195 196 /********************************************************** 197 * These are the state functions for handling chunk events. 198 **********************************************************/ 199 200 /* 201 * Process the final SHUTDOWN COMPLETE. 202 * 203 * Section: 4 (C) (diagram), 9.2 204 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 205 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 206 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 207 * should stop the T2-shutdown timer and remove all knowledge of the 208 * association (and thus the association enters the CLOSED state). 209 * 210 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 211 * C) Rules for packet carrying SHUTDOWN COMPLETE: 212 * ... 213 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 214 * if the Verification Tag field of the packet matches its own tag and 215 * the T bit is not set 216 * OR 217 * it is set to its peer's tag and the T bit is set in the Chunk 218 * Flags. 219 * Otherwise, the receiver MUST silently discard the packet 220 * and take no further action. An endpoint MUST ignore the 221 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 222 * 223 * Inputs 224 * (endpoint, asoc, chunk) 225 * 226 * Outputs 227 * (asoc, reply_msg, msg_up, timers, counters) 228 * 229 * The return value is the disposition of the chunk. 230 */ 231 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 232 const struct sctp_endpoint *ep, 233 const struct sctp_association *asoc, 234 const union sctp_subtype type, 235 void *arg, struct sctp_cmd_seq *commands) 236 { 237 struct sctp_chunk *chunk = arg; 238 struct sctp_ulpevent *ev; 239 240 if (!sctp_vtag_verify_either(chunk, asoc)) 241 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 242 243 /* RFC 2960 6.10 Bundling 244 * 245 * An endpoint MUST NOT bundle INIT, INIT ACK or 246 * SHUTDOWN COMPLETE with any other chunks. 247 */ 248 if (!chunk->singleton) 249 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 250 251 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 252 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 253 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 254 commands); 255 256 /* RFC 2960 10.2 SCTP-to-ULP 257 * 258 * H) SHUTDOWN COMPLETE notification 259 * 260 * When SCTP completes the shutdown procedures (section 9.2) this 261 * notification is passed to the upper layer. 262 */ 263 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 264 0, 0, 0, NULL, GFP_ATOMIC); 265 if (ev) 266 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 267 SCTP_ULPEVENT(ev)); 268 269 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 270 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 271 * not the chunk should be discarded. If the endpoint is in 272 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 273 * T2-shutdown timer and remove all knowledge of the 274 * association (and thus the association enters the CLOSED 275 * state). 276 */ 277 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 278 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 279 280 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 281 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 282 283 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 284 SCTP_STATE(SCTP_STATE_CLOSED)); 285 286 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 287 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 288 289 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 290 291 return SCTP_DISPOSITION_DELETE_TCB; 292 } 293 294 /* 295 * Respond to a normal INIT chunk. 296 * We are the side that is being asked for an association. 297 * 298 * Section: 5.1 Normal Establishment of an Association, B 299 * B) "Z" shall respond immediately with an INIT ACK chunk. The 300 * destination IP address of the INIT ACK MUST be set to the source 301 * IP address of the INIT to which this INIT ACK is responding. In 302 * the response, besides filling in other parameters, "Z" must set the 303 * Verification Tag field to Tag_A, and also provide its own 304 * Verification Tag (Tag_Z) in the Initiate Tag field. 305 * 306 * Verification Tag: Must be 0. 307 * 308 * Inputs 309 * (endpoint, asoc, chunk) 310 * 311 * Outputs 312 * (asoc, reply_msg, msg_up, timers, counters) 313 * 314 * The return value is the disposition of the chunk. 315 */ 316 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 317 const struct sctp_endpoint *ep, 318 const struct sctp_association *asoc, 319 const union sctp_subtype type, 320 void *arg, 321 struct sctp_cmd_seq *commands) 322 { 323 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 324 struct sctp_unrecognized_param *unk_param; 325 struct sctp_association *new_asoc; 326 struct sctp_packet *packet; 327 int len; 328 329 /* 6.10 Bundling 330 * An endpoint MUST NOT bundle INIT, INIT ACK or 331 * SHUTDOWN COMPLETE with any other chunks. 332 * 333 * IG Section 2.11.2 334 * Furthermore, we require that the receiver of an INIT chunk MUST 335 * enforce these rules by silently discarding an arriving packet 336 * with an INIT chunk that is bundled with other chunks. 337 */ 338 if (!chunk->singleton) 339 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 340 341 /* Make sure that the INIT chunk has a valid length. 342 * Normally, this would cause an ABORT with a Protocol Violation 343 * error, but since we don't have an association, we'll 344 * just discard the packet. 345 */ 346 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 348 349 /* If the packet is an OOTB packet which is temporarily on the 350 * control endpoint, respond with an ABORT. 351 */ 352 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 353 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 354 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 355 } 356 357 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 358 * Tag. 359 */ 360 if (chunk->sctp_hdr->vtag != 0) 361 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 362 363 /* If the INIT is coming toward a closing socket, we'll send back 364 * and ABORT. Essentially, this catches the race of INIT being 365 * backloged to the socket at the same time as the user issues close(). 366 * Since the socket and all its associations are going away, we 367 * can treat this OOTB 368 */ 369 if (sctp_sstate(ep->base.sk, CLOSING)) 370 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 371 372 /* Verify the INIT chunk before processing it. */ 373 err_chunk = NULL; 374 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 375 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 376 &err_chunk)) { 377 /* This chunk contains fatal error. It is to be discarded. 378 * Send an ABORT, with causes if there is any. 379 */ 380 if (err_chunk) { 381 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 382 (__u8 *)(err_chunk->chunk_hdr) + 383 sizeof(struct sctp_chunkhdr), 384 ntohs(err_chunk->chunk_hdr->length) - 385 sizeof(struct sctp_chunkhdr)); 386 387 sctp_chunk_free(err_chunk); 388 389 if (packet) { 390 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 391 SCTP_PACKET(packet)); 392 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 393 return SCTP_DISPOSITION_CONSUME; 394 } else { 395 return SCTP_DISPOSITION_NOMEM; 396 } 397 } else { 398 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 399 commands); 400 } 401 } 402 403 /* Grab the INIT header. */ 404 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 405 406 /* Tag the variable length parameters. */ 407 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 408 409 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 410 if (!new_asoc) 411 goto nomem; 412 413 /* Update socket peer label if first association. */ 414 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 415 sctp_association_free(new_asoc); 416 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 417 } 418 419 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 420 sctp_scope(sctp_source(chunk)), 421 GFP_ATOMIC) < 0) 422 goto nomem_init; 423 424 /* The call, sctp_process_init(), can fail on memory allocation. */ 425 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 426 (struct sctp_init_chunk *)chunk->chunk_hdr, 427 GFP_ATOMIC)) 428 goto nomem_init; 429 430 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 431 432 /* If there are errors need to be reported for unknown parameters, 433 * make sure to reserve enough room in the INIT ACK for them. 434 */ 435 len = 0; 436 if (err_chunk) 437 len = ntohs(err_chunk->chunk_hdr->length) - 438 sizeof(struct sctp_chunkhdr); 439 440 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 441 if (!repl) 442 goto nomem_init; 443 444 /* If there are errors need to be reported for unknown parameters, 445 * include them in the outgoing INIT ACK as "Unrecognized parameter" 446 * parameter. 447 */ 448 if (err_chunk) { 449 /* Get the "Unrecognized parameter" parameter(s) out of the 450 * ERROR chunk generated by sctp_verify_init(). Since the 451 * error cause code for "unknown parameter" and the 452 * "Unrecognized parameter" type is the same, we can 453 * construct the parameters in INIT ACK by copying the 454 * ERROR causes over. 455 */ 456 unk_param = (struct sctp_unrecognized_param *) 457 ((__u8 *)(err_chunk->chunk_hdr) + 458 sizeof(struct sctp_chunkhdr)); 459 /* Replace the cause code with the "Unrecognized parameter" 460 * parameter type. 461 */ 462 sctp_addto_chunk(repl, len, unk_param); 463 sctp_chunk_free(err_chunk); 464 } 465 466 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 467 468 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 469 470 /* 471 * Note: After sending out INIT ACK with the State Cookie parameter, 472 * "Z" MUST NOT allocate any resources, nor keep any states for the 473 * new association. Otherwise, "Z" will be vulnerable to resource 474 * attacks. 475 */ 476 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 477 478 return SCTP_DISPOSITION_DELETE_TCB; 479 480 nomem_init: 481 sctp_association_free(new_asoc); 482 nomem: 483 if (err_chunk) 484 sctp_chunk_free(err_chunk); 485 return SCTP_DISPOSITION_NOMEM; 486 } 487 488 /* 489 * Respond to a normal INIT ACK chunk. 490 * We are the side that is initiating the association. 491 * 492 * Section: 5.1 Normal Establishment of an Association, C 493 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 494 * timer and leave COOKIE-WAIT state. "A" shall then send the State 495 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 496 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 497 * 498 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 499 * DATA chunks, but it MUST be the first chunk in the packet and 500 * until the COOKIE ACK is returned the sender MUST NOT send any 501 * other packets to the peer. 502 * 503 * Verification Tag: 3.3.3 504 * If the value of the Initiate Tag in a received INIT ACK chunk is 505 * found to be 0, the receiver MUST treat it as an error and close the 506 * association by transmitting an ABORT. 507 * 508 * Inputs 509 * (endpoint, asoc, chunk) 510 * 511 * Outputs 512 * (asoc, reply_msg, msg_up, timers, counters) 513 * 514 * The return value is the disposition of the chunk. 515 */ 516 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 517 const struct sctp_endpoint *ep, 518 const struct sctp_association *asoc, 519 const union sctp_subtype type, 520 void *arg, 521 struct sctp_cmd_seq *commands) 522 { 523 struct sctp_init_chunk *initchunk; 524 struct sctp_chunk *chunk = arg; 525 struct sctp_chunk *err_chunk; 526 struct sctp_packet *packet; 527 528 if (!sctp_vtag_verify(chunk, asoc)) 529 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 530 531 /* 6.10 Bundling 532 * An endpoint MUST NOT bundle INIT, INIT ACK or 533 * SHUTDOWN COMPLETE with any other chunks. 534 */ 535 if (!chunk->singleton) 536 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 537 538 /* Make sure that the INIT-ACK chunk has a valid length */ 539 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 540 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 541 commands); 542 /* Grab the INIT header. */ 543 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 544 545 /* Verify the INIT chunk before processing it. */ 546 err_chunk = NULL; 547 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 548 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 549 &err_chunk)) { 550 551 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 552 553 /* This chunk contains fatal error. It is to be discarded. 554 * Send an ABORT, with causes. If there are no causes, 555 * then there wasn't enough memory. Just terminate 556 * the association. 557 */ 558 if (err_chunk) { 559 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 560 (__u8 *)(err_chunk->chunk_hdr) + 561 sizeof(struct sctp_chunkhdr), 562 ntohs(err_chunk->chunk_hdr->length) - 563 sizeof(struct sctp_chunkhdr)); 564 565 sctp_chunk_free(err_chunk); 566 567 if (packet) { 568 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 569 SCTP_PACKET(packet)); 570 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 571 error = SCTP_ERROR_INV_PARAM; 572 } 573 } 574 575 /* SCTP-AUTH, Section 6.3: 576 * It should be noted that if the receiver wants to tear 577 * down an association in an authenticated way only, the 578 * handling of malformed packets should not result in 579 * tearing down the association. 580 * 581 * This means that if we only want to abort associations 582 * in an authenticated way (i.e AUTH+ABORT), then we 583 * can't destroy this association just because the packet 584 * was malformed. 585 */ 586 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 587 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 588 589 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 590 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 591 asoc, chunk->transport); 592 } 593 594 /* Tag the variable length parameters. Note that we never 595 * convert the parameters in an INIT chunk. 596 */ 597 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 598 599 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 600 601 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 602 SCTP_PEER_INIT(initchunk)); 603 604 /* Reset init error count upon receipt of INIT-ACK. */ 605 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 606 607 /* 5.1 C) "A" shall stop the T1-init timer and leave 608 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 609 * timer, and enter the COOKIE-ECHOED state. 610 */ 611 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 612 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 613 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 614 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 615 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 616 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 617 618 /* SCTP-AUTH: generate the association shared keys so that 619 * we can potentially sign the COOKIE-ECHO. 620 */ 621 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 622 623 /* 5.1 C) "A" shall then send the State Cookie received in the 624 * INIT ACK chunk in a COOKIE ECHO chunk, ... 625 */ 626 /* If there is any errors to report, send the ERROR chunk generated 627 * for unknown parameters as well. 628 */ 629 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 630 SCTP_CHUNK(err_chunk)); 631 632 return SCTP_DISPOSITION_CONSUME; 633 } 634 635 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, 636 const struct sctp_association *asoc) 637 { 638 struct sctp_chunk auth; 639 640 if (!chunk->auth_chunk) 641 return true; 642 643 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 644 * is supposed to be authenticated and we have to do delayed 645 * authentication. We've just recreated the association using 646 * the information in the cookie and now it's much easier to 647 * do the authentication. 648 */ 649 650 /* Make sure that we and the peer are AUTH capable */ 651 if (!net->sctp.auth_enable || !asoc->peer.auth_capable) 652 return false; 653 654 /* set-up our fake chunk so that we can process it */ 655 auth.skb = chunk->auth_chunk; 656 auth.asoc = chunk->asoc; 657 auth.sctp_hdr = chunk->sctp_hdr; 658 auth.chunk_hdr = (struct sctp_chunkhdr *) 659 skb_push(chunk->auth_chunk, 660 sizeof(struct sctp_chunkhdr)); 661 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 662 auth.transport = chunk->transport; 663 664 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR; 665 } 666 667 /* 668 * Respond to a normal COOKIE ECHO chunk. 669 * We are the side that is being asked for an association. 670 * 671 * Section: 5.1 Normal Establishment of an Association, D 672 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 673 * with a COOKIE ACK chunk after building a TCB and moving to 674 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 675 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 676 * chunk MUST be the first chunk in the packet. 677 * 678 * IMPLEMENTATION NOTE: An implementation may choose to send the 679 * Communication Up notification to the SCTP user upon reception 680 * of a valid COOKIE ECHO chunk. 681 * 682 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 683 * D) Rules for packet carrying a COOKIE ECHO 684 * 685 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 686 * Initial Tag received in the INIT ACK. 687 * 688 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 689 * 690 * Inputs 691 * (endpoint, asoc, chunk) 692 * 693 * Outputs 694 * (asoc, reply_msg, msg_up, timers, counters) 695 * 696 * The return value is the disposition of the chunk. 697 */ 698 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 699 const struct sctp_endpoint *ep, 700 const struct sctp_association *asoc, 701 const union sctp_subtype type, 702 void *arg, 703 struct sctp_cmd_seq *commands) 704 { 705 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 706 struct sctp_association *new_asoc; 707 struct sctp_init_chunk *peer_init; 708 struct sctp_chunk *chunk = arg; 709 struct sctp_chunk *err_chk_p; 710 struct sctp_chunk *repl; 711 struct sock *sk; 712 int error = 0; 713 714 if (asoc && !sctp_vtag_verify(chunk, asoc)) 715 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 716 717 /* If the packet is an OOTB packet which is temporarily on the 718 * control endpoint, respond with an ABORT. 719 */ 720 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 721 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 722 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 723 } 724 725 /* Make sure that the COOKIE_ECHO chunk has a valid length. 726 * In this case, we check that we have enough for at least a 727 * chunk header. More detailed verification is done 728 * in sctp_unpack_cookie(). 729 */ 730 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 731 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 732 commands); 733 734 /* If the endpoint is not listening or if the number of associations 735 * on the TCP-style socket exceed the max backlog, respond with an 736 * ABORT. 737 */ 738 sk = ep->base.sk; 739 if (!sctp_sstate(sk, LISTENING) || 740 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 741 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 742 743 /* "Decode" the chunk. We have no optional parameters so we 744 * are in good shape. 745 */ 746 chunk->subh.cookie_hdr = 747 (struct sctp_signed_cookie *)chunk->skb->data; 748 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 749 sizeof(struct sctp_chunkhdr))) 750 goto nomem; 751 752 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 753 * "Z" will reply with a COOKIE ACK chunk after building a TCB 754 * and moving to the ESTABLISHED state. 755 */ 756 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 757 &err_chk_p); 758 759 /* FIXME: 760 * If the re-build failed, what is the proper error path 761 * from here? 762 * 763 * [We should abort the association. --piggy] 764 */ 765 if (!new_asoc) { 766 /* FIXME: Several errors are possible. A bad cookie should 767 * be silently discarded, but think about logging it too. 768 */ 769 switch (error) { 770 case -SCTP_IERROR_NOMEM: 771 goto nomem; 772 773 case -SCTP_IERROR_STALE_COOKIE: 774 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 775 err_chk_p); 776 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 777 778 case -SCTP_IERROR_BAD_SIG: 779 default: 780 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 781 } 782 } 783 784 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) { 785 sctp_association_free(new_asoc); 786 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 787 } 788 789 /* Delay state machine commands until later. 790 * 791 * Re-build the bind address for the association is done in 792 * the sctp_unpack_cookie() already. 793 */ 794 /* This is a brand-new association, so these are not yet side 795 * effects--it is safe to run them here. 796 */ 797 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 798 if (!sctp_process_init(new_asoc, chunk, 799 &chunk->subh.cookie_hdr->c.peer_addr, 800 peer_init, GFP_ATOMIC)) 801 goto nomem_init; 802 803 /* SCTP-AUTH: Now that we've populate required fields in 804 * sctp_process_init, set up the association shared keys as 805 * necessary so that we can potentially authenticate the ACK 806 */ 807 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 808 if (error) 809 goto nomem_init; 810 811 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) { 812 sctp_association_free(new_asoc); 813 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 814 } 815 816 repl = sctp_make_cookie_ack(new_asoc, chunk); 817 if (!repl) 818 goto nomem_init; 819 820 /* RFC 2960 5.1 Normal Establishment of an Association 821 * 822 * D) IMPLEMENTATION NOTE: An implementation may choose to 823 * send the Communication Up notification to the SCTP user 824 * upon reception of a valid COOKIE ECHO chunk. 825 */ 826 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 827 new_asoc->c.sinit_num_ostreams, 828 new_asoc->c.sinit_max_instreams, 829 NULL, GFP_ATOMIC); 830 if (!ev) 831 goto nomem_ev; 832 833 /* Sockets API Draft Section 5.3.1.6 834 * When a peer sends a Adaptation Layer Indication parameter , SCTP 835 * delivers this notification to inform the application that of the 836 * peers requested adaptation layer. 837 */ 838 if (new_asoc->peer.adaptation_ind) { 839 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 840 GFP_ATOMIC); 841 if (!ai_ev) 842 goto nomem_aiev; 843 } 844 845 if (!new_asoc->peer.auth_capable) { 846 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 847 SCTP_AUTH_NO_AUTH, 848 GFP_ATOMIC); 849 if (!auth_ev) 850 goto nomem_authev; 851 } 852 853 /* Add all the state machine commands now since we've created 854 * everything. This way we don't introduce memory corruptions 855 * during side-effect processing and correctly count established 856 * associations. 857 */ 858 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 859 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 860 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 861 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 862 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 863 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 864 865 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 866 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 867 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 868 869 /* This will send the COOKIE ACK */ 870 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 871 872 /* Queue the ASSOC_CHANGE event */ 873 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 874 875 /* Send up the Adaptation Layer Indication event */ 876 if (ai_ev) 877 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 878 SCTP_ULPEVENT(ai_ev)); 879 880 if (auth_ev) 881 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 882 SCTP_ULPEVENT(auth_ev)); 883 884 return SCTP_DISPOSITION_CONSUME; 885 886 nomem_authev: 887 sctp_ulpevent_free(ai_ev); 888 nomem_aiev: 889 sctp_ulpevent_free(ev); 890 nomem_ev: 891 sctp_chunk_free(repl); 892 nomem_init: 893 sctp_association_free(new_asoc); 894 nomem: 895 return SCTP_DISPOSITION_NOMEM; 896 } 897 898 /* 899 * Respond to a normal COOKIE ACK chunk. 900 * We are the side that is asking for an association. 901 * 902 * RFC 2960 5.1 Normal Establishment of an Association 903 * 904 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 905 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 906 * timer. It may also notify its ULP about the successful 907 * establishment of the association with a Communication Up 908 * notification (see Section 10). 909 * 910 * Verification Tag: 911 * Inputs 912 * (endpoint, asoc, chunk) 913 * 914 * Outputs 915 * (asoc, reply_msg, msg_up, timers, counters) 916 * 917 * The return value is the disposition of the chunk. 918 */ 919 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 920 const struct sctp_endpoint *ep, 921 const struct sctp_association *asoc, 922 const union sctp_subtype type, 923 void *arg, 924 struct sctp_cmd_seq *commands) 925 { 926 struct sctp_chunk *chunk = arg; 927 struct sctp_ulpevent *ev; 928 929 if (!sctp_vtag_verify(chunk, asoc)) 930 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 931 932 /* Set peer label for connection. */ 933 if (security_sctp_assoc_established((struct sctp_association *)asoc, 934 chunk->head_skb ?: chunk->skb)) 935 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 936 937 /* Verify that the chunk length for the COOKIE-ACK is OK. 938 * If we don't do this, any bundled chunks may be junked. 939 */ 940 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 941 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 942 commands); 943 944 /* Reset init error count upon receipt of COOKIE-ACK, 945 * to avoid problems with the management of this 946 * counter in stale cookie situations when a transition back 947 * from the COOKIE-ECHOED state to the COOKIE-WAIT 948 * state is performed. 949 */ 950 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 951 952 /* RFC 2960 5.1 Normal Establishment of an Association 953 * 954 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 955 * from the COOKIE-ECHOED state to the ESTABLISHED state, 956 * stopping the T1-cookie timer. 957 */ 958 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 959 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 960 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 961 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 962 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 963 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 964 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 965 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 966 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 967 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 968 969 /* It may also notify its ULP about the successful 970 * establishment of the association with a Communication Up 971 * notification (see Section 10). 972 */ 973 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 974 0, asoc->c.sinit_num_ostreams, 975 asoc->c.sinit_max_instreams, 976 NULL, GFP_ATOMIC); 977 978 if (!ev) 979 goto nomem; 980 981 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 982 983 /* Sockets API Draft Section 5.3.1.6 984 * When a peer sends a Adaptation Layer Indication parameter , SCTP 985 * delivers this notification to inform the application that of the 986 * peers requested adaptation layer. 987 */ 988 if (asoc->peer.adaptation_ind) { 989 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 990 if (!ev) 991 goto nomem; 992 993 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 994 SCTP_ULPEVENT(ev)); 995 } 996 997 if (!asoc->peer.auth_capable) { 998 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 999 GFP_ATOMIC); 1000 if (!ev) 1001 goto nomem; 1002 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1003 SCTP_ULPEVENT(ev)); 1004 } 1005 1006 return SCTP_DISPOSITION_CONSUME; 1007 nomem: 1008 return SCTP_DISPOSITION_NOMEM; 1009 } 1010 1011 /* Generate and sendout a heartbeat packet. */ 1012 static enum sctp_disposition sctp_sf_heartbeat( 1013 const struct sctp_endpoint *ep, 1014 const struct sctp_association *asoc, 1015 const union sctp_subtype type, 1016 void *arg, 1017 struct sctp_cmd_seq *commands) 1018 { 1019 struct sctp_transport *transport = (struct sctp_transport *) arg; 1020 struct sctp_chunk *reply; 1021 1022 /* Send a heartbeat to our peer. */ 1023 reply = sctp_make_heartbeat(asoc, transport, 0); 1024 if (!reply) 1025 return SCTP_DISPOSITION_NOMEM; 1026 1027 /* Set rto_pending indicating that an RTT measurement 1028 * is started with this heartbeat chunk. 1029 */ 1030 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1031 SCTP_TRANSPORT(transport)); 1032 1033 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1034 return SCTP_DISPOSITION_CONSUME; 1035 } 1036 1037 /* Generate a HEARTBEAT packet on the given transport. */ 1038 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1039 const struct sctp_endpoint *ep, 1040 const struct sctp_association *asoc, 1041 const union sctp_subtype type, 1042 void *arg, 1043 struct sctp_cmd_seq *commands) 1044 { 1045 struct sctp_transport *transport = (struct sctp_transport *) arg; 1046 1047 if (asoc->overall_error_count >= asoc->max_retrans) { 1048 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1049 SCTP_ERROR(ETIMEDOUT)); 1050 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1051 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1052 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1053 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1054 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1055 return SCTP_DISPOSITION_DELETE_TCB; 1056 } 1057 1058 /* Section 3.3.5. 1059 * The Sender-specific Heartbeat Info field should normally include 1060 * information about the sender's current time when this HEARTBEAT 1061 * chunk is sent and the destination transport address to which this 1062 * HEARTBEAT is sent (see Section 8.3). 1063 */ 1064 1065 if (transport->param_flags & SPP_HB_ENABLE) { 1066 if (SCTP_DISPOSITION_NOMEM == 1067 sctp_sf_heartbeat(ep, asoc, type, arg, 1068 commands)) 1069 return SCTP_DISPOSITION_NOMEM; 1070 1071 /* Set transport error counter and association error counter 1072 * when sending heartbeat. 1073 */ 1074 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1075 SCTP_TRANSPORT(transport)); 1076 } 1077 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1078 SCTP_TRANSPORT(transport)); 1079 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1080 SCTP_TRANSPORT(transport)); 1081 1082 return SCTP_DISPOSITION_CONSUME; 1083 } 1084 1085 /* resend asoc strreset_chunk. */ 1086 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1087 const struct sctp_endpoint *ep, 1088 const struct sctp_association *asoc, 1089 const union sctp_subtype type, 1090 void *arg, 1091 struct sctp_cmd_seq *commands) 1092 { 1093 struct sctp_transport *transport = arg; 1094 1095 if (asoc->overall_error_count >= asoc->max_retrans) { 1096 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1097 SCTP_ERROR(ETIMEDOUT)); 1098 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1099 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1100 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1101 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1102 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1103 return SCTP_DISPOSITION_DELETE_TCB; 1104 } 1105 1106 sctp_chunk_hold(asoc->strreset_chunk); 1107 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1108 SCTP_CHUNK(asoc->strreset_chunk)); 1109 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1110 1111 return SCTP_DISPOSITION_CONSUME; 1112 } 1113 1114 /* send hb chunk with padding for PLPMUTD. */ 1115 enum sctp_disposition sctp_sf_send_probe(struct net *net, 1116 const struct sctp_endpoint *ep, 1117 const struct sctp_association *asoc, 1118 const union sctp_subtype type, 1119 void *arg, 1120 struct sctp_cmd_seq *commands) 1121 { 1122 struct sctp_transport *transport = (struct sctp_transport *)arg; 1123 struct sctp_chunk *reply; 1124 1125 if (!sctp_transport_pl_enabled(transport)) 1126 return SCTP_DISPOSITION_CONSUME; 1127 1128 sctp_transport_pl_send(transport); 1129 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size); 1130 if (!reply) 1131 return SCTP_DISPOSITION_NOMEM; 1132 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1133 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE, 1134 SCTP_TRANSPORT(transport)); 1135 1136 return SCTP_DISPOSITION_CONSUME; 1137 } 1138 1139 /* 1140 * Process an heartbeat request. 1141 * 1142 * Section: 8.3 Path Heartbeat 1143 * The receiver of the HEARTBEAT should immediately respond with a 1144 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1145 * from the received HEARTBEAT chunk. 1146 * 1147 * Verification Tag: 8.5 Verification Tag [Normal verification] 1148 * When receiving an SCTP packet, the endpoint MUST ensure that the 1149 * value in the Verification Tag field of the received SCTP packet 1150 * matches its own Tag. If the received Verification Tag value does not 1151 * match the receiver's own tag value, the receiver shall silently 1152 * discard the packet and shall not process it any further except for 1153 * those cases listed in Section 8.5.1 below. 1154 * 1155 * Inputs 1156 * (endpoint, asoc, chunk) 1157 * 1158 * Outputs 1159 * (asoc, reply_msg, msg_up, timers, counters) 1160 * 1161 * The return value is the disposition of the chunk. 1162 */ 1163 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1164 const struct sctp_endpoint *ep, 1165 const struct sctp_association *asoc, 1166 const union sctp_subtype type, 1167 void *arg, struct sctp_cmd_seq *commands) 1168 { 1169 struct sctp_paramhdr *param_hdr; 1170 struct sctp_chunk *chunk = arg; 1171 struct sctp_chunk *reply; 1172 size_t paylen = 0; 1173 1174 if (!sctp_vtag_verify(chunk, asoc)) 1175 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1176 1177 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1178 if (!sctp_chunk_length_valid(chunk, 1179 sizeof(struct sctp_heartbeat_chunk))) 1180 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1181 commands); 1182 1183 /* 8.3 The receiver of the HEARTBEAT should immediately 1184 * respond with a HEARTBEAT ACK that contains the Heartbeat 1185 * Information field copied from the received HEARTBEAT chunk. 1186 */ 1187 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1188 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1189 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1190 1191 if (ntohs(param_hdr->length) > paylen) 1192 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1193 param_hdr, commands); 1194 1195 if (!pskb_pull(chunk->skb, paylen)) 1196 goto nomem; 1197 1198 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1199 if (!reply) 1200 goto nomem; 1201 1202 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1203 return SCTP_DISPOSITION_CONSUME; 1204 1205 nomem: 1206 return SCTP_DISPOSITION_NOMEM; 1207 } 1208 1209 /* 1210 * Process the returning HEARTBEAT ACK. 1211 * 1212 * Section: 8.3 Path Heartbeat 1213 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1214 * should clear the error counter of the destination transport 1215 * address to which the HEARTBEAT was sent, and mark the destination 1216 * transport address as active if it is not so marked. The endpoint may 1217 * optionally report to the upper layer when an inactive destination 1218 * address is marked as active due to the reception of the latest 1219 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1220 * clear the association overall error count as well (as defined 1221 * in section 8.1). 1222 * 1223 * The receiver of the HEARTBEAT ACK should also perform an RTT 1224 * measurement for that destination transport address using the time 1225 * value carried in the HEARTBEAT ACK chunk. 1226 * 1227 * Verification Tag: 8.5 Verification Tag [Normal verification] 1228 * 1229 * Inputs 1230 * (endpoint, asoc, chunk) 1231 * 1232 * Outputs 1233 * (asoc, reply_msg, msg_up, timers, counters) 1234 * 1235 * The return value is the disposition of the chunk. 1236 */ 1237 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1238 const struct sctp_endpoint *ep, 1239 const struct sctp_association *asoc, 1240 const union sctp_subtype type, 1241 void *arg, 1242 struct sctp_cmd_seq *commands) 1243 { 1244 struct sctp_sender_hb_info *hbinfo; 1245 struct sctp_chunk *chunk = arg; 1246 struct sctp_transport *link; 1247 unsigned long max_interval; 1248 union sctp_addr from_addr; 1249 1250 if (!sctp_vtag_verify(chunk, asoc)) 1251 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1252 1253 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1254 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1255 sizeof(*hbinfo))) 1256 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1257 commands); 1258 1259 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1260 /* Make sure that the length of the parameter is what we expect */ 1261 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1262 return SCTP_DISPOSITION_DISCARD; 1263 1264 from_addr = hbinfo->daddr; 1265 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1266 1267 /* This should never happen, but lets log it if so. */ 1268 if (unlikely(!link)) { 1269 if (from_addr.sa.sa_family == AF_INET6) { 1270 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1271 __func__, 1272 asoc, 1273 &from_addr.v6.sin6_addr); 1274 } else { 1275 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1276 __func__, 1277 asoc, 1278 &from_addr.v4.sin_addr.s_addr); 1279 } 1280 return SCTP_DISPOSITION_DISCARD; 1281 } 1282 1283 /* Validate the 64-bit random nonce. */ 1284 if (hbinfo->hb_nonce != link->hb_nonce) 1285 return SCTP_DISPOSITION_DISCARD; 1286 1287 if (hbinfo->probe_size) { 1288 if (hbinfo->probe_size != link->pl.probe_size || 1289 !sctp_transport_pl_enabled(link)) 1290 return SCTP_DISPOSITION_DISCARD; 1291 1292 if (sctp_transport_pl_recv(link)) 1293 return SCTP_DISPOSITION_CONSUME; 1294 1295 return sctp_sf_send_probe(net, ep, asoc, type, link, commands); 1296 } 1297 1298 max_interval = link->hbinterval + link->rto; 1299 1300 /* Check if the timestamp looks valid. */ 1301 if (time_after(hbinfo->sent_at, jiffies) || 1302 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1303 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1304 "for transport:%p\n", __func__, link); 1305 1306 return SCTP_DISPOSITION_DISCARD; 1307 } 1308 1309 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1310 * the HEARTBEAT should clear the error counter of the 1311 * destination transport address to which the HEARTBEAT was 1312 * sent and mark the destination transport address as active if 1313 * it is not so marked. 1314 */ 1315 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1316 1317 return SCTP_DISPOSITION_CONSUME; 1318 } 1319 1320 /* Helper function to send out an abort for the restart 1321 * condition. 1322 */ 1323 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1324 struct sctp_chunk *init, 1325 struct sctp_cmd_seq *commands) 1326 { 1327 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1328 union sctp_addr_param *addrparm; 1329 struct sctp_errhdr *errhdr; 1330 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1331 struct sctp_endpoint *ep; 1332 struct sctp_packet *pkt; 1333 int len; 1334 1335 /* Build the error on the stack. We are way to malloc crazy 1336 * throughout the code today. 1337 */ 1338 errhdr = (struct sctp_errhdr *)buffer; 1339 addrparm = (union sctp_addr_param *)(errhdr + 1); 1340 1341 /* Copy into a parm format. */ 1342 len = af->to_addr_param(ssa, addrparm); 1343 len += sizeof(*errhdr); 1344 1345 errhdr->cause = SCTP_ERROR_RESTART; 1346 errhdr->length = htons(len); 1347 1348 /* Assign to the control socket. */ 1349 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1350 1351 /* Association is NULL since this may be a restart attack and we 1352 * want to send back the attacker's vtag. 1353 */ 1354 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1355 1356 if (!pkt) 1357 goto out; 1358 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1359 1360 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1361 1362 /* Discard the rest of the inbound packet. */ 1363 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1364 1365 out: 1366 /* Even if there is no memory, treat as a failure so 1367 * the packet will get dropped. 1368 */ 1369 return 0; 1370 } 1371 1372 static bool list_has_sctp_addr(const struct list_head *list, 1373 union sctp_addr *ipaddr) 1374 { 1375 struct sctp_transport *addr; 1376 1377 list_for_each_entry(addr, list, transports) { 1378 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1379 return true; 1380 } 1381 1382 return false; 1383 } 1384 /* A restart is occurring, check to make sure no new addresses 1385 * are being added as we may be under a takeover attack. 1386 */ 1387 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1388 const struct sctp_association *asoc, 1389 struct sctp_chunk *init, 1390 struct sctp_cmd_seq *commands) 1391 { 1392 struct net *net = new_asoc->base.net; 1393 struct sctp_transport *new_addr; 1394 int ret = 1; 1395 1396 /* Implementor's Guide - Section 5.2.2 1397 * ... 1398 * Before responding the endpoint MUST check to see if the 1399 * unexpected INIT adds new addresses to the association. If new 1400 * addresses are added to the association, the endpoint MUST respond 1401 * with an ABORT.. 1402 */ 1403 1404 /* Search through all current addresses and make sure 1405 * we aren't adding any new ones. 1406 */ 1407 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1408 transports) { 1409 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1410 &new_addr->ipaddr)) { 1411 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1412 commands); 1413 ret = 0; 1414 break; 1415 } 1416 } 1417 1418 /* Return success if all addresses were found. */ 1419 return ret; 1420 } 1421 1422 /* Populate the verification/tie tags based on overlapping INIT 1423 * scenario. 1424 * 1425 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1426 */ 1427 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1428 const struct sctp_association *asoc) 1429 { 1430 switch (asoc->state) { 1431 1432 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1433 1434 case SCTP_STATE_COOKIE_WAIT: 1435 new_asoc->c.my_vtag = asoc->c.my_vtag; 1436 new_asoc->c.my_ttag = asoc->c.my_vtag; 1437 new_asoc->c.peer_ttag = 0; 1438 break; 1439 1440 case SCTP_STATE_COOKIE_ECHOED: 1441 new_asoc->c.my_vtag = asoc->c.my_vtag; 1442 new_asoc->c.my_ttag = asoc->c.my_vtag; 1443 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1444 break; 1445 1446 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1447 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1448 */ 1449 default: 1450 new_asoc->c.my_ttag = asoc->c.my_vtag; 1451 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1452 break; 1453 } 1454 1455 /* Other parameters for the endpoint SHOULD be copied from the 1456 * existing parameters of the association (e.g. number of 1457 * outbound streams) into the INIT ACK and cookie. 1458 */ 1459 new_asoc->rwnd = asoc->rwnd; 1460 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1461 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1462 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1463 } 1464 1465 /* 1466 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1467 * handling action. 1468 * 1469 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1470 * 1471 * Returns value representing action to be taken. These action values 1472 * correspond to Action/Description values in RFC 2960, Table 2. 1473 */ 1474 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1475 const struct sctp_association *asoc) 1476 { 1477 /* In this case, the peer may have restarted. */ 1478 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1479 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1480 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1481 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1482 return 'A'; 1483 1484 /* Collision case B. */ 1485 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1486 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1487 (0 == asoc->c.peer_vtag))) { 1488 return 'B'; 1489 } 1490 1491 /* Collision case D. */ 1492 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1493 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1494 return 'D'; 1495 1496 /* Collision case C. */ 1497 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1498 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1499 (0 == new_asoc->c.my_ttag) && 1500 (0 == new_asoc->c.peer_ttag)) 1501 return 'C'; 1502 1503 /* No match to any of the special cases; discard this packet. */ 1504 return 'E'; 1505 } 1506 1507 /* Common helper routine for both duplicate and simultaneous INIT 1508 * chunk handling. 1509 */ 1510 static enum sctp_disposition sctp_sf_do_unexpected_init( 1511 struct net *net, 1512 const struct sctp_endpoint *ep, 1513 const struct sctp_association *asoc, 1514 const union sctp_subtype type, 1515 void *arg, 1516 struct sctp_cmd_seq *commands) 1517 { 1518 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1519 struct sctp_unrecognized_param *unk_param; 1520 struct sctp_association *new_asoc; 1521 enum sctp_disposition retval; 1522 struct sctp_packet *packet; 1523 int len; 1524 1525 /* 6.10 Bundling 1526 * An endpoint MUST NOT bundle INIT, INIT ACK or 1527 * SHUTDOWN COMPLETE with any other chunks. 1528 * 1529 * IG Section 2.11.2 1530 * Furthermore, we require that the receiver of an INIT chunk MUST 1531 * enforce these rules by silently discarding an arriving packet 1532 * with an INIT chunk that is bundled with other chunks. 1533 */ 1534 if (!chunk->singleton) 1535 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1536 1537 /* Make sure that the INIT chunk has a valid length. */ 1538 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1539 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1540 1541 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1542 * Tag. 1543 */ 1544 if (chunk->sctp_hdr->vtag != 0) 1545 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1546 1547 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port) 1548 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands); 1549 1550 /* Grab the INIT header. */ 1551 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1552 1553 /* Tag the variable length parameters. */ 1554 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1555 1556 /* Verify the INIT chunk before processing it. */ 1557 err_chunk = NULL; 1558 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1559 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1560 &err_chunk)) { 1561 /* This chunk contains fatal error. It is to be discarded. 1562 * Send an ABORT, with causes if there is any. 1563 */ 1564 if (err_chunk) { 1565 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1566 (__u8 *)(err_chunk->chunk_hdr) + 1567 sizeof(struct sctp_chunkhdr), 1568 ntohs(err_chunk->chunk_hdr->length) - 1569 sizeof(struct sctp_chunkhdr)); 1570 1571 if (packet) { 1572 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1573 SCTP_PACKET(packet)); 1574 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1575 retval = SCTP_DISPOSITION_CONSUME; 1576 } else { 1577 retval = SCTP_DISPOSITION_NOMEM; 1578 } 1579 goto cleanup; 1580 } else { 1581 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1582 commands); 1583 } 1584 } 1585 1586 /* 1587 * Other parameters for the endpoint SHOULD be copied from the 1588 * existing parameters of the association (e.g. number of 1589 * outbound streams) into the INIT ACK and cookie. 1590 * FIXME: We are copying parameters from the endpoint not the 1591 * association. 1592 */ 1593 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1594 if (!new_asoc) 1595 goto nomem; 1596 1597 /* Update socket peer label if first association. */ 1598 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 1599 sctp_association_free(new_asoc); 1600 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1601 } 1602 1603 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1604 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1605 goto nomem; 1606 1607 /* In the outbound INIT ACK the endpoint MUST copy its current 1608 * Verification Tag and Peers Verification tag into a reserved 1609 * place (local tie-tag and per tie-tag) within the state cookie. 1610 */ 1611 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1612 (struct sctp_init_chunk *)chunk->chunk_hdr, 1613 GFP_ATOMIC)) 1614 goto nomem; 1615 1616 /* Make sure no new addresses are being added during the 1617 * restart. Do not do this check for COOKIE-WAIT state, 1618 * since there are no peer addresses to check against. 1619 * Upon return an ABORT will have been sent if needed. 1620 */ 1621 if (!sctp_state(asoc, COOKIE_WAIT)) { 1622 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1623 commands)) { 1624 retval = SCTP_DISPOSITION_CONSUME; 1625 goto nomem_retval; 1626 } 1627 } 1628 1629 sctp_tietags_populate(new_asoc, asoc); 1630 1631 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1632 1633 /* If there are errors need to be reported for unknown parameters, 1634 * make sure to reserve enough room in the INIT ACK for them. 1635 */ 1636 len = 0; 1637 if (err_chunk) { 1638 len = ntohs(err_chunk->chunk_hdr->length) - 1639 sizeof(struct sctp_chunkhdr); 1640 } 1641 1642 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1643 if (!repl) 1644 goto nomem; 1645 1646 /* If there are errors need to be reported for unknown parameters, 1647 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1648 * parameter. 1649 */ 1650 if (err_chunk) { 1651 /* Get the "Unrecognized parameter" parameter(s) out of the 1652 * ERROR chunk generated by sctp_verify_init(). Since the 1653 * error cause code for "unknown parameter" and the 1654 * "Unrecognized parameter" type is the same, we can 1655 * construct the parameters in INIT ACK by copying the 1656 * ERROR causes over. 1657 */ 1658 unk_param = (struct sctp_unrecognized_param *) 1659 ((__u8 *)(err_chunk->chunk_hdr) + 1660 sizeof(struct sctp_chunkhdr)); 1661 /* Replace the cause code with the "Unrecognized parameter" 1662 * parameter type. 1663 */ 1664 sctp_addto_chunk(repl, len, unk_param); 1665 } 1666 1667 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1668 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1669 1670 /* 1671 * Note: After sending out INIT ACK with the State Cookie parameter, 1672 * "Z" MUST NOT allocate any resources for this new association. 1673 * Otherwise, "Z" will be vulnerable to resource attacks. 1674 */ 1675 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1676 retval = SCTP_DISPOSITION_CONSUME; 1677 1678 return retval; 1679 1680 nomem: 1681 retval = SCTP_DISPOSITION_NOMEM; 1682 nomem_retval: 1683 if (new_asoc) 1684 sctp_association_free(new_asoc); 1685 cleanup: 1686 if (err_chunk) 1687 sctp_chunk_free(err_chunk); 1688 return retval; 1689 } 1690 1691 /* 1692 * Handle simultaneous INIT. 1693 * This means we started an INIT and then we got an INIT request from 1694 * our peer. 1695 * 1696 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1697 * This usually indicates an initialization collision, i.e., each 1698 * endpoint is attempting, at about the same time, to establish an 1699 * association with the other endpoint. 1700 * 1701 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1702 * endpoint MUST respond with an INIT ACK using the same parameters it 1703 * sent in its original INIT chunk (including its Verification Tag, 1704 * unchanged). These original parameters are combined with those from the 1705 * newly received INIT chunk. The endpoint shall also generate a State 1706 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1707 * INIT to calculate the State Cookie. 1708 * 1709 * After that, the endpoint MUST NOT change its state, the T1-init 1710 * timer shall be left running and the corresponding TCB MUST NOT be 1711 * destroyed. The normal procedures for handling State Cookies when 1712 * a TCB exists will resolve the duplicate INITs to a single association. 1713 * 1714 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1715 * its Tie-Tags with the Tag information of itself and its peer (see 1716 * section 5.2.2 for a description of the Tie-Tags). 1717 * 1718 * Verification Tag: Not explicit, but an INIT can not have a valid 1719 * verification tag, so we skip the check. 1720 * 1721 * Inputs 1722 * (endpoint, asoc, chunk) 1723 * 1724 * Outputs 1725 * (asoc, reply_msg, msg_up, timers, counters) 1726 * 1727 * The return value is the disposition of the chunk. 1728 */ 1729 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1730 struct net *net, 1731 const struct sctp_endpoint *ep, 1732 const struct sctp_association *asoc, 1733 const union sctp_subtype type, 1734 void *arg, 1735 struct sctp_cmd_seq *commands) 1736 { 1737 /* Call helper to do the real work for both simultaneous and 1738 * duplicate INIT chunk handling. 1739 */ 1740 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1741 } 1742 1743 /* 1744 * Handle duplicated INIT messages. These are usually delayed 1745 * restransmissions. 1746 * 1747 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1748 * COOKIE-ECHOED and COOKIE-WAIT 1749 * 1750 * Unless otherwise stated, upon reception of an unexpected INIT for 1751 * this association, the endpoint shall generate an INIT ACK with a 1752 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1753 * current Verification Tag and peer's Verification Tag into a reserved 1754 * place within the state cookie. We shall refer to these locations as 1755 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1756 * containing this INIT ACK MUST carry a Verification Tag value equal to 1757 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1758 * MUST contain a new Initiation Tag (randomly generated see Section 1759 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1760 * existing parameters of the association (e.g. number of outbound 1761 * streams) into the INIT ACK and cookie. 1762 * 1763 * After sending out the INIT ACK, the endpoint shall take no further 1764 * actions, i.e., the existing association, including its current state, 1765 * and the corresponding TCB MUST NOT be changed. 1766 * 1767 * Note: Only when a TCB exists and the association is not in a COOKIE- 1768 * WAIT state are the Tie-Tags populated. For a normal association INIT 1769 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1770 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1771 * State Cookie are populated as specified in section 5.2.1. 1772 * 1773 * Verification Tag: Not specified, but an INIT has no way of knowing 1774 * what the verification tag could be, so we ignore it. 1775 * 1776 * Inputs 1777 * (endpoint, asoc, chunk) 1778 * 1779 * Outputs 1780 * (asoc, reply_msg, msg_up, timers, counters) 1781 * 1782 * The return value is the disposition of the chunk. 1783 */ 1784 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1785 struct net *net, 1786 const struct sctp_endpoint *ep, 1787 const struct sctp_association *asoc, 1788 const union sctp_subtype type, 1789 void *arg, 1790 struct sctp_cmd_seq *commands) 1791 { 1792 /* Call helper to do the real work for both simultaneous and 1793 * duplicate INIT chunk handling. 1794 */ 1795 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1796 } 1797 1798 1799 /* 1800 * Unexpected INIT-ACK handler. 1801 * 1802 * Section 5.2.3 1803 * If an INIT ACK received by an endpoint in any state other than the 1804 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1805 * An unexpected INIT ACK usually indicates the processing of an old or 1806 * duplicated INIT chunk. 1807 */ 1808 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1809 struct net *net, 1810 const struct sctp_endpoint *ep, 1811 const struct sctp_association *asoc, 1812 const union sctp_subtype type, 1813 void *arg, 1814 struct sctp_cmd_seq *commands) 1815 { 1816 /* Per the above section, we'll discard the chunk if we have an 1817 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1818 */ 1819 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1820 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1821 else 1822 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1823 } 1824 1825 static int sctp_sf_do_assoc_update(struct sctp_association *asoc, 1826 struct sctp_association *new, 1827 struct sctp_cmd_seq *cmds) 1828 { 1829 struct net *net = asoc->base.net; 1830 struct sctp_chunk *abort; 1831 1832 if (!sctp_assoc_update(asoc, new)) 1833 return 0; 1834 1835 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr)); 1836 if (abort) { 1837 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 1838 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 1839 } 1840 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED)); 1841 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED, 1842 SCTP_PERR(SCTP_ERROR_RSRC_LOW)); 1843 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1844 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1845 1846 return -ENOMEM; 1847 } 1848 1849 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1850 * 1851 * Section 5.2.4 1852 * A) In this case, the peer may have restarted. 1853 */ 1854 static enum sctp_disposition sctp_sf_do_dupcook_a( 1855 struct net *net, 1856 const struct sctp_endpoint *ep, 1857 const struct sctp_association *asoc, 1858 struct sctp_chunk *chunk, 1859 struct sctp_cmd_seq *commands, 1860 struct sctp_association *new_asoc) 1861 { 1862 struct sctp_init_chunk *peer_init; 1863 enum sctp_disposition disposition; 1864 struct sctp_ulpevent *ev; 1865 struct sctp_chunk *repl; 1866 struct sctp_chunk *err; 1867 1868 /* new_asoc is a brand-new association, so these are not yet 1869 * side effects--it is safe to run them here. 1870 */ 1871 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1872 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1873 GFP_ATOMIC)) 1874 goto nomem; 1875 1876 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1877 goto nomem; 1878 1879 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1880 return SCTP_DISPOSITION_DISCARD; 1881 1882 /* Make sure no new addresses are being added during the 1883 * restart. Though this is a pretty complicated attack 1884 * since you'd have to get inside the cookie. 1885 */ 1886 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1887 return SCTP_DISPOSITION_CONSUME; 1888 1889 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1890 * the peer has restarted (Action A), it MUST NOT setup a new 1891 * association but instead resend the SHUTDOWN ACK and send an ERROR 1892 * chunk with a "Cookie Received while Shutting Down" error cause to 1893 * its peer. 1894 */ 1895 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1896 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc, 1897 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1898 chunk, commands); 1899 if (SCTP_DISPOSITION_NOMEM == disposition) 1900 goto nomem; 1901 1902 err = sctp_make_op_error(asoc, chunk, 1903 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1904 NULL, 0, 0); 1905 if (err) 1906 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1907 SCTP_CHUNK(err)); 1908 1909 return SCTP_DISPOSITION_CONSUME; 1910 } 1911 1912 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1913 * data. Consider the optional choice of resending of this data. 1914 */ 1915 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1916 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1917 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1918 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1919 1920 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1921 * and ASCONF-ACK cache. 1922 */ 1923 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1924 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1925 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1926 1927 /* Update the content of current association. */ 1928 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1929 goto nomem; 1930 1931 repl = sctp_make_cookie_ack(asoc, chunk); 1932 if (!repl) 1933 goto nomem; 1934 1935 /* Report association restart to upper layer. */ 1936 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1937 asoc->c.sinit_num_ostreams, 1938 asoc->c.sinit_max_instreams, 1939 NULL, GFP_ATOMIC); 1940 if (!ev) 1941 goto nomem_ev; 1942 1943 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1944 if ((sctp_state(asoc, SHUTDOWN_PENDING) || 1945 sctp_state(asoc, SHUTDOWN_SENT)) && 1946 (sctp_sstate(asoc->base.sk, CLOSING) || 1947 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1948 /* If the socket has been closed by user, don't 1949 * transition to ESTABLISHED. Instead trigger SHUTDOWN 1950 * bundled with COOKIE_ACK. 1951 */ 1952 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1953 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1954 SCTP_ST_CHUNK(0), repl, 1955 commands); 1956 } else { 1957 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1958 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1959 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1960 } 1961 return SCTP_DISPOSITION_CONSUME; 1962 1963 nomem_ev: 1964 sctp_chunk_free(repl); 1965 nomem: 1966 return SCTP_DISPOSITION_NOMEM; 1967 } 1968 1969 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1970 * 1971 * Section 5.2.4 1972 * B) In this case, both sides may be attempting to start an association 1973 * at about the same time but the peer endpoint started its INIT 1974 * after responding to the local endpoint's INIT 1975 */ 1976 /* This case represents an initialization collision. */ 1977 static enum sctp_disposition sctp_sf_do_dupcook_b( 1978 struct net *net, 1979 const struct sctp_endpoint *ep, 1980 const struct sctp_association *asoc, 1981 struct sctp_chunk *chunk, 1982 struct sctp_cmd_seq *commands, 1983 struct sctp_association *new_asoc) 1984 { 1985 struct sctp_init_chunk *peer_init; 1986 struct sctp_chunk *repl; 1987 1988 /* new_asoc is a brand-new association, so these are not yet 1989 * side effects--it is safe to run them here. 1990 */ 1991 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1992 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1993 GFP_ATOMIC)) 1994 goto nomem; 1995 1996 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1997 goto nomem; 1998 1999 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 2000 return SCTP_DISPOSITION_DISCARD; 2001 2002 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2003 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2004 if (asoc->state < SCTP_STATE_ESTABLISHED) 2005 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2006 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 2007 2008 /* Update the content of current association. */ 2009 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 2010 goto nomem; 2011 2012 repl = sctp_make_cookie_ack(asoc, chunk); 2013 if (!repl) 2014 goto nomem; 2015 2016 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2017 2018 /* RFC 2960 5.1 Normal Establishment of an Association 2019 * 2020 * D) IMPLEMENTATION NOTE: An implementation may choose to 2021 * send the Communication Up notification to the SCTP user 2022 * upon reception of a valid COOKIE ECHO chunk. 2023 * 2024 * Sadly, this needs to be implemented as a side-effect, because 2025 * we are not guaranteed to have set the association id of the real 2026 * association and so these notifications need to be delayed until 2027 * the association id is allocated. 2028 */ 2029 2030 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 2031 2032 /* Sockets API Draft Section 5.3.1.6 2033 * When a peer sends a Adaptation Layer Indication parameter , SCTP 2034 * delivers this notification to inform the application that of the 2035 * peers requested adaptation layer. 2036 * 2037 * This also needs to be done as a side effect for the same reason as 2038 * above. 2039 */ 2040 if (asoc->peer.adaptation_ind) 2041 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 2042 2043 if (!asoc->peer.auth_capable) 2044 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 2045 2046 return SCTP_DISPOSITION_CONSUME; 2047 2048 nomem: 2049 return SCTP_DISPOSITION_NOMEM; 2050 } 2051 2052 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 2053 * 2054 * Section 5.2.4 2055 * C) In this case, the local endpoint's cookie has arrived late. 2056 * Before it arrived, the local endpoint sent an INIT and received an 2057 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 2058 * but a new tag of its own. 2059 */ 2060 /* This case represents an initialization collision. */ 2061 static enum sctp_disposition sctp_sf_do_dupcook_c( 2062 struct net *net, 2063 const struct sctp_endpoint *ep, 2064 const struct sctp_association *asoc, 2065 struct sctp_chunk *chunk, 2066 struct sctp_cmd_seq *commands, 2067 struct sctp_association *new_asoc) 2068 { 2069 /* The cookie should be silently discarded. 2070 * The endpoint SHOULD NOT change states and should leave 2071 * any timers running. 2072 */ 2073 return SCTP_DISPOSITION_DISCARD; 2074 } 2075 2076 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 2077 * 2078 * Section 5.2.4 2079 * 2080 * D) When both local and remote tags match the endpoint should always 2081 * enter the ESTABLISHED state, if it has not already done so. 2082 */ 2083 /* This case represents an initialization collision. */ 2084 static enum sctp_disposition sctp_sf_do_dupcook_d( 2085 struct net *net, 2086 const struct sctp_endpoint *ep, 2087 const struct sctp_association *asoc, 2088 struct sctp_chunk *chunk, 2089 struct sctp_cmd_seq *commands, 2090 struct sctp_association *new_asoc) 2091 { 2092 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2093 struct sctp_chunk *repl; 2094 2095 /* Clarification from Implementor's Guide: 2096 * D) When both local and remote tags match the endpoint should 2097 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2098 * It should stop any cookie timer that may be running and send 2099 * a COOKIE ACK. 2100 */ 2101 2102 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2103 return SCTP_DISPOSITION_DISCARD; 2104 2105 /* Don't accidentally move back into established state. */ 2106 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2107 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2108 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2109 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2110 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2111 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2112 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2113 SCTP_NULL()); 2114 2115 /* RFC 2960 5.1 Normal Establishment of an Association 2116 * 2117 * D) IMPLEMENTATION NOTE: An implementation may choose 2118 * to send the Communication Up notification to the 2119 * SCTP user upon reception of a valid COOKIE 2120 * ECHO chunk. 2121 */ 2122 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2123 SCTP_COMM_UP, 0, 2124 asoc->c.sinit_num_ostreams, 2125 asoc->c.sinit_max_instreams, 2126 NULL, GFP_ATOMIC); 2127 if (!ev) 2128 goto nomem; 2129 2130 /* Sockets API Draft Section 5.3.1.6 2131 * When a peer sends a Adaptation Layer Indication parameter, 2132 * SCTP delivers this notification to inform the application 2133 * that of the peers requested adaptation layer. 2134 */ 2135 if (asoc->peer.adaptation_ind) { 2136 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2137 GFP_ATOMIC); 2138 if (!ai_ev) 2139 goto nomem; 2140 2141 } 2142 2143 if (!asoc->peer.auth_capable) { 2144 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2145 SCTP_AUTH_NO_AUTH, 2146 GFP_ATOMIC); 2147 if (!auth_ev) 2148 goto nomem; 2149 } 2150 } 2151 2152 repl = sctp_make_cookie_ack(asoc, chunk); 2153 if (!repl) 2154 goto nomem; 2155 2156 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2157 2158 if (ev) 2159 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2160 SCTP_ULPEVENT(ev)); 2161 if (ai_ev) 2162 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2163 SCTP_ULPEVENT(ai_ev)); 2164 if (auth_ev) 2165 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2166 SCTP_ULPEVENT(auth_ev)); 2167 2168 return SCTP_DISPOSITION_CONSUME; 2169 2170 nomem: 2171 if (auth_ev) 2172 sctp_ulpevent_free(auth_ev); 2173 if (ai_ev) 2174 sctp_ulpevent_free(ai_ev); 2175 if (ev) 2176 sctp_ulpevent_free(ev); 2177 return SCTP_DISPOSITION_NOMEM; 2178 } 2179 2180 /* 2181 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2182 * chunk was retransmitted and then delayed in the network. 2183 * 2184 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2185 * 2186 * Verification Tag: None. Do cookie validation. 2187 * 2188 * Inputs 2189 * (endpoint, asoc, chunk) 2190 * 2191 * Outputs 2192 * (asoc, reply_msg, msg_up, timers, counters) 2193 * 2194 * The return value is the disposition of the chunk. 2195 */ 2196 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2197 struct net *net, 2198 const struct sctp_endpoint *ep, 2199 const struct sctp_association *asoc, 2200 const union sctp_subtype type, 2201 void *arg, 2202 struct sctp_cmd_seq *commands) 2203 { 2204 struct sctp_association *new_asoc; 2205 struct sctp_chunk *chunk = arg; 2206 enum sctp_disposition retval; 2207 struct sctp_chunk *err_chk_p; 2208 int error = 0; 2209 char action; 2210 2211 /* Make sure that the chunk has a valid length from the protocol 2212 * perspective. In this case check to make sure we have at least 2213 * enough for the chunk header. Cookie length verification is 2214 * done later. 2215 */ 2216 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) { 2217 if (!sctp_vtag_verify(chunk, asoc)) 2218 asoc = NULL; 2219 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); 2220 } 2221 2222 /* "Decode" the chunk. We have no optional parameters so we 2223 * are in good shape. 2224 */ 2225 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2226 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2227 sizeof(struct sctp_chunkhdr))) 2228 goto nomem; 2229 2230 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2231 * of a duplicate COOKIE ECHO match the Verification Tags of the 2232 * current association, consider the State Cookie valid even if 2233 * the lifespan is exceeded. 2234 */ 2235 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2236 &err_chk_p); 2237 2238 /* FIXME: 2239 * If the re-build failed, what is the proper error path 2240 * from here? 2241 * 2242 * [We should abort the association. --piggy] 2243 */ 2244 if (!new_asoc) { 2245 /* FIXME: Several errors are possible. A bad cookie should 2246 * be silently discarded, but think about logging it too. 2247 */ 2248 switch (error) { 2249 case -SCTP_IERROR_NOMEM: 2250 goto nomem; 2251 2252 case -SCTP_IERROR_STALE_COOKIE: 2253 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2254 err_chk_p); 2255 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2256 case -SCTP_IERROR_BAD_SIG: 2257 default: 2258 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2259 } 2260 } 2261 2262 /* Set temp so that it won't be added into hashtable */ 2263 new_asoc->temp = 1; 2264 2265 /* Compare the tie_tag in cookie with the verification tag of 2266 * current association. 2267 */ 2268 action = sctp_tietags_compare(new_asoc, asoc); 2269 2270 /* In cases C and E the association doesn't enter the ESTABLISHED 2271 * state, so there is no need to call security_sctp_assoc_request(). 2272 */ 2273 switch (action) { 2274 case 'A': /* Association restart. */ 2275 case 'B': /* Collision case B. */ 2276 case 'D': /* Collision case D. */ 2277 /* Update socket peer label if first association. */ 2278 if (security_sctp_assoc_request((struct sctp_association *)asoc, 2279 chunk->head_skb ?: chunk->skb)) { 2280 sctp_association_free(new_asoc); 2281 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2282 } 2283 break; 2284 } 2285 2286 switch (action) { 2287 case 'A': /* Association restart. */ 2288 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2289 new_asoc); 2290 break; 2291 2292 case 'B': /* Collision case B. */ 2293 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2294 new_asoc); 2295 break; 2296 2297 case 'C': /* Collision case C. */ 2298 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2299 new_asoc); 2300 break; 2301 2302 case 'D': /* Collision case D. */ 2303 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2304 new_asoc); 2305 break; 2306 2307 default: /* Discard packet for all others. */ 2308 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2309 break; 2310 } 2311 2312 /* Delete the temporary new association. */ 2313 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2314 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2315 2316 /* Restore association pointer to provide SCTP command interpreter 2317 * with a valid context in case it needs to manipulate 2318 * the queues */ 2319 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2320 SCTP_ASOC((struct sctp_association *)asoc)); 2321 2322 return retval; 2323 2324 nomem: 2325 return SCTP_DISPOSITION_NOMEM; 2326 } 2327 2328 /* 2329 * Process an ABORT. (SHUTDOWN-PENDING state) 2330 * 2331 * See sctp_sf_do_9_1_abort(). 2332 */ 2333 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2334 struct net *net, 2335 const struct sctp_endpoint *ep, 2336 const struct sctp_association *asoc, 2337 const union sctp_subtype type, 2338 void *arg, 2339 struct sctp_cmd_seq *commands) 2340 { 2341 struct sctp_chunk *chunk = arg; 2342 2343 if (!sctp_vtag_verify_either(chunk, asoc)) 2344 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2345 2346 /* Make sure that the ABORT chunk has a valid length. 2347 * Since this is an ABORT chunk, we have to discard it 2348 * because of the following text: 2349 * RFC 2960, Section 3.3.7 2350 * If an endpoint receives an ABORT with a format error or for an 2351 * association that doesn't exist, it MUST silently discard it. 2352 * Because the length is "invalid", we can't really discard just 2353 * as we do not know its true length. So, to be safe, discard the 2354 * packet. 2355 */ 2356 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2357 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2358 2359 /* ADD-IP: Special case for ABORT chunks 2360 * F4) One special consideration is that ABORT Chunks arriving 2361 * destined to the IP address being deleted MUST be 2362 * ignored (see Section 5.3.1 for further details). 2363 */ 2364 if (SCTP_ADDR_DEL == 2365 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2366 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2367 2368 if (!sctp_err_chunk_valid(chunk)) 2369 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2370 2371 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2372 } 2373 2374 /* 2375 * Process an ABORT. (SHUTDOWN-SENT state) 2376 * 2377 * See sctp_sf_do_9_1_abort(). 2378 */ 2379 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2380 struct net *net, 2381 const struct sctp_endpoint *ep, 2382 const struct sctp_association *asoc, 2383 const union sctp_subtype type, 2384 void *arg, 2385 struct sctp_cmd_seq *commands) 2386 { 2387 struct sctp_chunk *chunk = arg; 2388 2389 if (!sctp_vtag_verify_either(chunk, asoc)) 2390 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2391 2392 /* Make sure that the ABORT chunk has a valid length. 2393 * Since this is an ABORT chunk, we have to discard it 2394 * because of the following text: 2395 * RFC 2960, Section 3.3.7 2396 * If an endpoint receives an ABORT with a format error or for an 2397 * association that doesn't exist, it MUST silently discard it. 2398 * Because the length is "invalid", we can't really discard just 2399 * as we do not know its true length. So, to be safe, discard the 2400 * packet. 2401 */ 2402 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2403 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2404 2405 /* ADD-IP: Special case for ABORT chunks 2406 * F4) One special consideration is that ABORT Chunks arriving 2407 * destined to the IP address being deleted MUST be 2408 * ignored (see Section 5.3.1 for further details). 2409 */ 2410 if (SCTP_ADDR_DEL == 2411 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2412 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2413 2414 if (!sctp_err_chunk_valid(chunk)) 2415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2416 2417 /* Stop the T2-shutdown timer. */ 2418 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2419 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2420 2421 /* Stop the T5-shutdown guard timer. */ 2422 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2423 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2424 2425 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2426 } 2427 2428 /* 2429 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2430 * 2431 * See sctp_sf_do_9_1_abort(). 2432 */ 2433 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2434 struct net *net, 2435 const struct sctp_endpoint *ep, 2436 const struct sctp_association *asoc, 2437 const union sctp_subtype type, 2438 void *arg, 2439 struct sctp_cmd_seq *commands) 2440 { 2441 /* The same T2 timer, so we should be able to use 2442 * common function with the SHUTDOWN-SENT state. 2443 */ 2444 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2445 } 2446 2447 /* 2448 * Handle an Error received in COOKIE_ECHOED state. 2449 * 2450 * Only handle the error type of stale COOKIE Error, the other errors will 2451 * be ignored. 2452 * 2453 * Inputs 2454 * (endpoint, asoc, chunk) 2455 * 2456 * Outputs 2457 * (asoc, reply_msg, msg_up, timers, counters) 2458 * 2459 * The return value is the disposition of the chunk. 2460 */ 2461 enum sctp_disposition sctp_sf_cookie_echoed_err( 2462 struct net *net, 2463 const struct sctp_endpoint *ep, 2464 const struct sctp_association *asoc, 2465 const union sctp_subtype type, 2466 void *arg, 2467 struct sctp_cmd_seq *commands) 2468 { 2469 struct sctp_chunk *chunk = arg; 2470 struct sctp_errhdr *err; 2471 2472 if (!sctp_vtag_verify(chunk, asoc)) 2473 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2474 2475 /* Make sure that the ERROR chunk has a valid length. 2476 * The parameter walking depends on this as well. 2477 */ 2478 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2479 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2480 commands); 2481 2482 /* Process the error here */ 2483 /* FUTURE FIXME: When PR-SCTP related and other optional 2484 * parms are emitted, this will have to change to handle multiple 2485 * errors. 2486 */ 2487 sctp_walk_errors(err, chunk->chunk_hdr) { 2488 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2489 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2490 arg, commands); 2491 } 2492 2493 /* It is possible to have malformed error causes, and that 2494 * will cause us to end the walk early. However, since 2495 * we are discarding the packet, there should be no adverse 2496 * affects. 2497 */ 2498 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2499 } 2500 2501 /* 2502 * Handle a Stale COOKIE Error 2503 * 2504 * Section: 5.2.6 Handle Stale COOKIE Error 2505 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2506 * one of the following three alternatives. 2507 * ... 2508 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2509 * Preservative parameter requesting an extension to the lifetime of 2510 * the State Cookie. When calculating the time extension, an 2511 * implementation SHOULD use the RTT information measured based on the 2512 * previous COOKIE ECHO / ERROR exchange, and should add no more 2513 * than 1 second beyond the measured RTT, due to long State Cookie 2514 * lifetimes making the endpoint more subject to a replay attack. 2515 * 2516 * Verification Tag: Not explicit, but safe to ignore. 2517 * 2518 * Inputs 2519 * (endpoint, asoc, chunk) 2520 * 2521 * Outputs 2522 * (asoc, reply_msg, msg_up, timers, counters) 2523 * 2524 * The return value is the disposition of the chunk. 2525 */ 2526 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2527 struct net *net, 2528 const struct sctp_endpoint *ep, 2529 const struct sctp_association *asoc, 2530 const union sctp_subtype type, 2531 void *arg, 2532 struct sctp_cmd_seq *commands) 2533 { 2534 int attempts = asoc->init_err_counter + 1; 2535 struct sctp_chunk *chunk = arg, *reply; 2536 struct sctp_cookie_preserve_param bht; 2537 struct sctp_bind_addr *bp; 2538 struct sctp_errhdr *err; 2539 u32 stale; 2540 2541 if (attempts > asoc->max_init_attempts) { 2542 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2543 SCTP_ERROR(ETIMEDOUT)); 2544 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2545 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2546 return SCTP_DISPOSITION_DELETE_TCB; 2547 } 2548 2549 err = (struct sctp_errhdr *)(chunk->skb->data); 2550 2551 /* When calculating the time extension, an implementation 2552 * SHOULD use the RTT information measured based on the 2553 * previous COOKIE ECHO / ERROR exchange, and should add no 2554 * more than 1 second beyond the measured RTT, due to long 2555 * State Cookie lifetimes making the endpoint more subject to 2556 * a replay attack. 2557 * Measure of Staleness's unit is usec. (1/1000000 sec) 2558 * Suggested Cookie Life-span Increment's unit is msec. 2559 * (1/1000 sec) 2560 * In general, if you use the suggested cookie life, the value 2561 * found in the field of measure of staleness should be doubled 2562 * to give ample time to retransmit the new cookie and thus 2563 * yield a higher probability of success on the reattempt. 2564 */ 2565 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2566 stale = (stale * 2) / 1000; 2567 2568 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2569 bht.param_hdr.length = htons(sizeof(bht)); 2570 bht.lifespan_increment = htonl(stale); 2571 2572 /* Build that new INIT chunk. */ 2573 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2574 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2575 if (!reply) 2576 goto nomem; 2577 2578 sctp_addto_chunk(reply, sizeof(bht), &bht); 2579 2580 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2581 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2582 2583 /* Stop pending T3-rtx and heartbeat timers */ 2584 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2585 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2586 2587 /* Delete non-primary peer ip addresses since we are transitioning 2588 * back to the COOKIE-WAIT state 2589 */ 2590 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2591 2592 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2593 * resend 2594 */ 2595 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2596 SCTP_TRANSPORT(asoc->peer.primary_path)); 2597 2598 /* Cast away the const modifier, as we want to just 2599 * rerun it through as a sideffect. 2600 */ 2601 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2602 2603 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2604 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2605 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2606 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2607 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2608 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2609 2610 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2611 2612 return SCTP_DISPOSITION_CONSUME; 2613 2614 nomem: 2615 return SCTP_DISPOSITION_NOMEM; 2616 } 2617 2618 /* 2619 * Process an ABORT. 2620 * 2621 * Section: 9.1 2622 * After checking the Verification Tag, the receiving endpoint shall 2623 * remove the association from its record, and shall report the 2624 * termination to its upper layer. 2625 * 2626 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2627 * B) Rules for packet carrying ABORT: 2628 * 2629 * - The endpoint shall always fill in the Verification Tag field of the 2630 * outbound packet with the destination endpoint's tag value if it 2631 * is known. 2632 * 2633 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2634 * MUST follow the procedure described in Section 8.4. 2635 * 2636 * - The receiver MUST accept the packet if the Verification Tag 2637 * matches either its own tag, OR the tag of its peer. Otherwise, the 2638 * receiver MUST silently discard the packet and take no further 2639 * action. 2640 * 2641 * Inputs 2642 * (endpoint, asoc, chunk) 2643 * 2644 * Outputs 2645 * (asoc, reply_msg, msg_up, timers, counters) 2646 * 2647 * The return value is the disposition of the chunk. 2648 */ 2649 enum sctp_disposition sctp_sf_do_9_1_abort( 2650 struct net *net, 2651 const struct sctp_endpoint *ep, 2652 const struct sctp_association *asoc, 2653 const union sctp_subtype type, 2654 void *arg, 2655 struct sctp_cmd_seq *commands) 2656 { 2657 struct sctp_chunk *chunk = arg; 2658 2659 if (!sctp_vtag_verify_either(chunk, asoc)) 2660 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2661 2662 /* Make sure that the ABORT chunk has a valid length. 2663 * Since this is an ABORT chunk, we have to discard it 2664 * because of the following text: 2665 * RFC 2960, Section 3.3.7 2666 * If an endpoint receives an ABORT with a format error or for an 2667 * association that doesn't exist, it MUST silently discard it. 2668 * Because the length is "invalid", we can't really discard just 2669 * as we do not know its true length. So, to be safe, discard the 2670 * packet. 2671 */ 2672 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2673 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2674 2675 /* ADD-IP: Special case for ABORT chunks 2676 * F4) One special consideration is that ABORT Chunks arriving 2677 * destined to the IP address being deleted MUST be 2678 * ignored (see Section 5.3.1 for further details). 2679 */ 2680 if (SCTP_ADDR_DEL == 2681 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2682 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2683 2684 if (!sctp_err_chunk_valid(chunk)) 2685 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2686 2687 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2688 } 2689 2690 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2691 struct net *net, 2692 const struct sctp_endpoint *ep, 2693 const struct sctp_association *asoc, 2694 const union sctp_subtype type, 2695 void *arg, 2696 struct sctp_cmd_seq *commands) 2697 { 2698 __be16 error = SCTP_ERROR_NO_ERROR; 2699 struct sctp_chunk *chunk = arg; 2700 unsigned int len; 2701 2702 /* See if we have an error cause code in the chunk. */ 2703 len = ntohs(chunk->chunk_hdr->length); 2704 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2705 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2706 2707 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2708 /* ASSOC_FAILED will DELETE_TCB. */ 2709 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2710 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2711 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2712 2713 return SCTP_DISPOSITION_ABORT; 2714 } 2715 2716 /* 2717 * Process an ABORT. (COOKIE-WAIT state) 2718 * 2719 * See sctp_sf_do_9_1_abort() above. 2720 */ 2721 enum sctp_disposition sctp_sf_cookie_wait_abort( 2722 struct net *net, 2723 const struct sctp_endpoint *ep, 2724 const struct sctp_association *asoc, 2725 const union sctp_subtype type, 2726 void *arg, 2727 struct sctp_cmd_seq *commands) 2728 { 2729 __be16 error = SCTP_ERROR_NO_ERROR; 2730 struct sctp_chunk *chunk = arg; 2731 unsigned int len; 2732 2733 if (!sctp_vtag_verify_either(chunk, asoc)) 2734 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2735 2736 /* Make sure that the ABORT chunk has a valid length. 2737 * Since this is an ABORT chunk, we have to discard it 2738 * because of the following text: 2739 * RFC 2960, Section 3.3.7 2740 * If an endpoint receives an ABORT with a format error or for an 2741 * association that doesn't exist, it MUST silently discard it. 2742 * Because the length is "invalid", we can't really discard just 2743 * as we do not know its true length. So, to be safe, discard the 2744 * packet. 2745 */ 2746 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2747 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2748 2749 /* See if we have an error cause code in the chunk. */ 2750 len = ntohs(chunk->chunk_hdr->length); 2751 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2752 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2753 2754 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2755 chunk->transport); 2756 } 2757 2758 /* 2759 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2760 */ 2761 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2762 struct net *net, 2763 const struct sctp_endpoint *ep, 2764 const struct sctp_association *asoc, 2765 const union sctp_subtype type, 2766 void *arg, 2767 struct sctp_cmd_seq *commands) 2768 { 2769 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2770 ENOPROTOOPT, asoc, 2771 (struct sctp_transport *)arg); 2772 } 2773 2774 /* 2775 * Process an ABORT. (COOKIE-ECHOED state) 2776 */ 2777 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2778 struct net *net, 2779 const struct sctp_endpoint *ep, 2780 const struct sctp_association *asoc, 2781 const union sctp_subtype type, 2782 void *arg, 2783 struct sctp_cmd_seq *commands) 2784 { 2785 /* There is a single T1 timer, so we should be able to use 2786 * common function with the COOKIE-WAIT state. 2787 */ 2788 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2789 } 2790 2791 /* 2792 * Stop T1 timer and abort association with "INIT failed". 2793 * 2794 * This is common code called by several sctp_sf_*_abort() functions above. 2795 */ 2796 static enum sctp_disposition sctp_stop_t1_and_abort( 2797 struct net *net, 2798 struct sctp_cmd_seq *commands, 2799 __be16 error, int sk_err, 2800 const struct sctp_association *asoc, 2801 struct sctp_transport *transport) 2802 { 2803 pr_debug("%s: ABORT received (INIT)\n", __func__); 2804 2805 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2806 SCTP_STATE(SCTP_STATE_CLOSED)); 2807 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2808 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2809 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2810 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2811 /* CMD_INIT_FAILED will DELETE_TCB. */ 2812 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2813 SCTP_PERR(error)); 2814 2815 return SCTP_DISPOSITION_ABORT; 2816 } 2817 2818 /* 2819 * sctp_sf_do_9_2_shut 2820 * 2821 * Section: 9.2 2822 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2823 * - enter the SHUTDOWN-RECEIVED state, 2824 * 2825 * - stop accepting new data from its SCTP user 2826 * 2827 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2828 * that all its outstanding DATA chunks have been received by the 2829 * SHUTDOWN sender. 2830 * 2831 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2832 * send a SHUTDOWN in response to a ULP request. And should discard 2833 * subsequent SHUTDOWN chunks. 2834 * 2835 * If there are still outstanding DATA chunks left, the SHUTDOWN 2836 * receiver shall continue to follow normal data transmission 2837 * procedures defined in Section 6 until all outstanding DATA chunks 2838 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2839 * new data from its SCTP user. 2840 * 2841 * Verification Tag: 8.5 Verification Tag [Normal verification] 2842 * 2843 * Inputs 2844 * (endpoint, asoc, chunk) 2845 * 2846 * Outputs 2847 * (asoc, reply_msg, msg_up, timers, counters) 2848 * 2849 * The return value is the disposition of the chunk. 2850 */ 2851 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2852 struct net *net, 2853 const struct sctp_endpoint *ep, 2854 const struct sctp_association *asoc, 2855 const union sctp_subtype type, 2856 void *arg, 2857 struct sctp_cmd_seq *commands) 2858 { 2859 enum sctp_disposition disposition; 2860 struct sctp_chunk *chunk = arg; 2861 struct sctp_shutdownhdr *sdh; 2862 struct sctp_ulpevent *ev; 2863 __u32 ctsn; 2864 2865 if (!sctp_vtag_verify(chunk, asoc)) 2866 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2867 2868 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2869 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2870 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2871 commands); 2872 2873 /* Convert the elaborate header. */ 2874 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2875 skb_pull(chunk->skb, sizeof(*sdh)); 2876 chunk->subh.shutdown_hdr = sdh; 2877 ctsn = ntohl(sdh->cum_tsn_ack); 2878 2879 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2880 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2881 asoc->ctsn_ack_point); 2882 2883 return SCTP_DISPOSITION_DISCARD; 2884 } 2885 2886 /* If Cumulative TSN Ack beyond the max tsn currently 2887 * send, terminating the association and respond to the 2888 * sender with an ABORT. 2889 */ 2890 if (!TSN_lt(ctsn, asoc->next_tsn)) 2891 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2892 2893 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2894 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2895 * inform the application that it should cease sending data. 2896 */ 2897 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2898 if (!ev) { 2899 disposition = SCTP_DISPOSITION_NOMEM; 2900 goto out; 2901 } 2902 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2903 2904 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2905 * - enter the SHUTDOWN-RECEIVED state, 2906 * - stop accepting new data from its SCTP user 2907 * 2908 * [This is implicit in the new state.] 2909 */ 2910 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2911 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2912 disposition = SCTP_DISPOSITION_CONSUME; 2913 2914 if (sctp_outq_is_empty(&asoc->outqueue)) { 2915 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2916 arg, commands); 2917 } 2918 2919 if (SCTP_DISPOSITION_NOMEM == disposition) 2920 goto out; 2921 2922 /* - verify, by checking the Cumulative TSN Ack field of the 2923 * chunk, that all its outstanding DATA chunks have been 2924 * received by the SHUTDOWN sender. 2925 */ 2926 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2927 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2928 2929 out: 2930 return disposition; 2931 } 2932 2933 /* 2934 * sctp_sf_do_9_2_shut_ctsn 2935 * 2936 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2937 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2938 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2939 * MUST be processed. 2940 */ 2941 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2942 struct net *net, 2943 const struct sctp_endpoint *ep, 2944 const struct sctp_association *asoc, 2945 const union sctp_subtype type, 2946 void *arg, 2947 struct sctp_cmd_seq *commands) 2948 { 2949 struct sctp_chunk *chunk = arg; 2950 struct sctp_shutdownhdr *sdh; 2951 __u32 ctsn; 2952 2953 if (!sctp_vtag_verify(chunk, asoc)) 2954 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2955 2956 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2957 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2958 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2959 commands); 2960 2961 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2962 ctsn = ntohl(sdh->cum_tsn_ack); 2963 2964 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2965 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2966 asoc->ctsn_ack_point); 2967 2968 return SCTP_DISPOSITION_DISCARD; 2969 } 2970 2971 /* If Cumulative TSN Ack beyond the max tsn currently 2972 * send, terminating the association and respond to the 2973 * sender with an ABORT. 2974 */ 2975 if (!TSN_lt(ctsn, asoc->next_tsn)) 2976 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2977 2978 /* verify, by checking the Cumulative TSN Ack field of the 2979 * chunk, that all its outstanding DATA chunks have been 2980 * received by the SHUTDOWN sender. 2981 */ 2982 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2983 SCTP_BE32(sdh->cum_tsn_ack)); 2984 2985 return SCTP_DISPOSITION_CONSUME; 2986 } 2987 2988 /* RFC 2960 9.2 2989 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2990 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2991 * transport addresses (either in the IP addresses or in the INIT chunk) 2992 * that belong to this association, it should discard the INIT chunk and 2993 * retransmit the SHUTDOWN ACK chunk. 2994 */ 2995 static enum sctp_disposition 2996 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 2997 const struct sctp_association *asoc, 2998 const union sctp_subtype type, void *arg, 2999 struct sctp_cmd_seq *commands) 3000 { 3001 struct sctp_chunk *chunk = arg; 3002 struct sctp_chunk *reply; 3003 3004 /* Make sure that the chunk has a valid length */ 3005 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3006 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3007 commands); 3008 3009 /* Since we are not going to really process this INIT, there 3010 * is no point in verifying chunk boundaries. Just generate 3011 * the SHUTDOWN ACK. 3012 */ 3013 reply = sctp_make_shutdown_ack(asoc, chunk); 3014 if (NULL == reply) 3015 goto nomem; 3016 3017 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 3018 * the T2-SHUTDOWN timer. 3019 */ 3020 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 3021 3022 /* and restart the T2-shutdown timer. */ 3023 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3024 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3025 3026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3027 3028 return SCTP_DISPOSITION_CONSUME; 3029 nomem: 3030 return SCTP_DISPOSITION_NOMEM; 3031 } 3032 3033 enum sctp_disposition 3034 sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3035 const struct sctp_association *asoc, 3036 const union sctp_subtype type, void *arg, 3037 struct sctp_cmd_seq *commands) 3038 { 3039 struct sctp_chunk *chunk = arg; 3040 3041 if (!chunk->singleton) 3042 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3043 3044 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 3045 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3046 3047 if (chunk->sctp_hdr->vtag != 0) 3048 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3049 3050 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands); 3051 } 3052 3053 /* 3054 * sctp_sf_do_ecn_cwr 3055 * 3056 * Section: Appendix A: Explicit Congestion Notification 3057 * 3058 * CWR: 3059 * 3060 * RFC 2481 details a specific bit for a sender to send in the header of 3061 * its next outbound TCP segment to indicate to its peer that it has 3062 * reduced its congestion window. This is termed the CWR bit. For 3063 * SCTP the same indication is made by including the CWR chunk. 3064 * This chunk contains one data element, i.e. the TSN number that 3065 * was sent in the ECNE chunk. This element represents the lowest 3066 * TSN number in the datagram that was originally marked with the 3067 * CE bit. 3068 * 3069 * Verification Tag: 8.5 Verification Tag [Normal verification] 3070 * Inputs 3071 * (endpoint, asoc, chunk) 3072 * 3073 * Outputs 3074 * (asoc, reply_msg, msg_up, timers, counters) 3075 * 3076 * The return value is the disposition of the chunk. 3077 */ 3078 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3079 const struct sctp_endpoint *ep, 3080 const struct sctp_association *asoc, 3081 const union sctp_subtype type, 3082 void *arg, 3083 struct sctp_cmd_seq *commands) 3084 { 3085 struct sctp_chunk *chunk = arg; 3086 struct sctp_cwrhdr *cwr; 3087 u32 lowest_tsn; 3088 3089 if (!sctp_vtag_verify(chunk, asoc)) 3090 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3091 3092 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3093 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3094 commands); 3095 3096 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3097 skb_pull(chunk->skb, sizeof(*cwr)); 3098 3099 lowest_tsn = ntohl(cwr->lowest_tsn); 3100 3101 /* Does this CWR ack the last sent congestion notification? */ 3102 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3103 /* Stop sending ECNE. */ 3104 sctp_add_cmd_sf(commands, 3105 SCTP_CMD_ECN_CWR, 3106 SCTP_U32(lowest_tsn)); 3107 } 3108 return SCTP_DISPOSITION_CONSUME; 3109 } 3110 3111 /* 3112 * sctp_sf_do_ecne 3113 * 3114 * Section: Appendix A: Explicit Congestion Notification 3115 * 3116 * ECN-Echo 3117 * 3118 * RFC 2481 details a specific bit for a receiver to send back in its 3119 * TCP acknowledgements to notify the sender of the Congestion 3120 * Experienced (CE) bit having arrived from the network. For SCTP this 3121 * same indication is made by including the ECNE chunk. This chunk 3122 * contains one data element, i.e. the lowest TSN associated with the IP 3123 * datagram marked with the CE bit..... 3124 * 3125 * Verification Tag: 8.5 Verification Tag [Normal verification] 3126 * Inputs 3127 * (endpoint, asoc, chunk) 3128 * 3129 * Outputs 3130 * (asoc, reply_msg, msg_up, timers, counters) 3131 * 3132 * The return value is the disposition of the chunk. 3133 */ 3134 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3135 const struct sctp_endpoint *ep, 3136 const struct sctp_association *asoc, 3137 const union sctp_subtype type, 3138 void *arg, struct sctp_cmd_seq *commands) 3139 { 3140 struct sctp_chunk *chunk = arg; 3141 struct sctp_ecnehdr *ecne; 3142 3143 if (!sctp_vtag_verify(chunk, asoc)) 3144 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3145 3146 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3147 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3148 commands); 3149 3150 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3151 skb_pull(chunk->skb, sizeof(*ecne)); 3152 3153 /* If this is a newer ECNE than the last CWR packet we sent out */ 3154 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3155 SCTP_U32(ntohl(ecne->lowest_tsn))); 3156 3157 return SCTP_DISPOSITION_CONSUME; 3158 } 3159 3160 /* 3161 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3162 * 3163 * The SCTP endpoint MUST always acknowledge the reception of each valid 3164 * DATA chunk. 3165 * 3166 * The guidelines on delayed acknowledgement algorithm specified in 3167 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3168 * acknowledgement SHOULD be generated for at least every second packet 3169 * (not every second DATA chunk) received, and SHOULD be generated within 3170 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3171 * situations it may be beneficial for an SCTP transmitter to be more 3172 * conservative than the algorithms detailed in this document allow. 3173 * However, an SCTP transmitter MUST NOT be more aggressive than the 3174 * following algorithms allow. 3175 * 3176 * A SCTP receiver MUST NOT generate more than one SACK for every 3177 * incoming packet, other than to update the offered window as the 3178 * receiving application consumes new data. 3179 * 3180 * Verification Tag: 8.5 Verification Tag [Normal verification] 3181 * 3182 * Inputs 3183 * (endpoint, asoc, chunk) 3184 * 3185 * Outputs 3186 * (asoc, reply_msg, msg_up, timers, counters) 3187 * 3188 * The return value is the disposition of the chunk. 3189 */ 3190 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3191 const struct sctp_endpoint *ep, 3192 const struct sctp_association *asoc, 3193 const union sctp_subtype type, 3194 void *arg, 3195 struct sctp_cmd_seq *commands) 3196 { 3197 union sctp_arg force = SCTP_NOFORCE(); 3198 struct sctp_chunk *chunk = arg; 3199 int error; 3200 3201 if (!sctp_vtag_verify(chunk, asoc)) { 3202 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3203 SCTP_NULL()); 3204 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3205 } 3206 3207 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3208 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3209 commands); 3210 3211 error = sctp_eat_data(asoc, chunk, commands); 3212 switch (error) { 3213 case SCTP_IERROR_NO_ERROR: 3214 break; 3215 case SCTP_IERROR_HIGH_TSN: 3216 case SCTP_IERROR_BAD_STREAM: 3217 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3218 goto discard_noforce; 3219 case SCTP_IERROR_DUP_TSN: 3220 case SCTP_IERROR_IGNORE_TSN: 3221 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3222 goto discard_force; 3223 case SCTP_IERROR_NO_DATA: 3224 return SCTP_DISPOSITION_ABORT; 3225 case SCTP_IERROR_PROTO_VIOLATION: 3226 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3227 (u8 *)chunk->subh.data_hdr, 3228 sctp_datahdr_len(&asoc->stream)); 3229 default: 3230 BUG(); 3231 } 3232 3233 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3234 force = SCTP_FORCE(); 3235 3236 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3237 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3238 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3239 } 3240 3241 /* If this is the last chunk in a packet, we need to count it 3242 * toward sack generation. Note that we need to SACK every 3243 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3244 * THEM. We elect to NOT generate SACK's if the chunk fails 3245 * the verification tag test. 3246 * 3247 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3248 * 3249 * The SCTP endpoint MUST always acknowledge the reception of 3250 * each valid DATA chunk. 3251 * 3252 * The guidelines on delayed acknowledgement algorithm 3253 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3254 * Specifically, an acknowledgement SHOULD be generated for at 3255 * least every second packet (not every second DATA chunk) 3256 * received, and SHOULD be generated within 200 ms of the 3257 * arrival of any unacknowledged DATA chunk. In some 3258 * situations it may be beneficial for an SCTP transmitter to 3259 * be more conservative than the algorithms detailed in this 3260 * document allow. However, an SCTP transmitter MUST NOT be 3261 * more aggressive than the following algorithms allow. 3262 */ 3263 if (chunk->end_of_packet) 3264 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3265 3266 return SCTP_DISPOSITION_CONSUME; 3267 3268 discard_force: 3269 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3270 * 3271 * When a packet arrives with duplicate DATA chunk(s) and with 3272 * no new DATA chunk(s), the endpoint MUST immediately send a 3273 * SACK with no delay. If a packet arrives with duplicate 3274 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3275 * MAY immediately send a SACK. Normally receipt of duplicate 3276 * DATA chunks will occur when the original SACK chunk was lost 3277 * and the peer's RTO has expired. The duplicate TSN number(s) 3278 * SHOULD be reported in the SACK as duplicate. 3279 */ 3280 /* In our case, we split the MAY SACK advice up whether or not 3281 * the last chunk is a duplicate.' 3282 */ 3283 if (chunk->end_of_packet) 3284 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3285 return SCTP_DISPOSITION_DISCARD; 3286 3287 discard_noforce: 3288 if (chunk->end_of_packet) 3289 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3290 3291 return SCTP_DISPOSITION_DISCARD; 3292 } 3293 3294 /* 3295 * sctp_sf_eat_data_fast_4_4 3296 * 3297 * Section: 4 (4) 3298 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3299 * DATA chunks without delay. 3300 * 3301 * Verification Tag: 8.5 Verification Tag [Normal verification] 3302 * Inputs 3303 * (endpoint, asoc, chunk) 3304 * 3305 * Outputs 3306 * (asoc, reply_msg, msg_up, timers, counters) 3307 * 3308 * The return value is the disposition of the chunk. 3309 */ 3310 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3311 struct net *net, 3312 const struct sctp_endpoint *ep, 3313 const struct sctp_association *asoc, 3314 const union sctp_subtype type, 3315 void *arg, 3316 struct sctp_cmd_seq *commands) 3317 { 3318 struct sctp_chunk *chunk = arg; 3319 int error; 3320 3321 if (!sctp_vtag_verify(chunk, asoc)) { 3322 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3323 SCTP_NULL()); 3324 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3325 } 3326 3327 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3328 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3329 commands); 3330 3331 error = sctp_eat_data(asoc, chunk, commands); 3332 switch (error) { 3333 case SCTP_IERROR_NO_ERROR: 3334 case SCTP_IERROR_HIGH_TSN: 3335 case SCTP_IERROR_DUP_TSN: 3336 case SCTP_IERROR_IGNORE_TSN: 3337 case SCTP_IERROR_BAD_STREAM: 3338 break; 3339 case SCTP_IERROR_NO_DATA: 3340 return SCTP_DISPOSITION_ABORT; 3341 case SCTP_IERROR_PROTO_VIOLATION: 3342 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3343 (u8 *)chunk->subh.data_hdr, 3344 sctp_datahdr_len(&asoc->stream)); 3345 default: 3346 BUG(); 3347 } 3348 3349 /* Go a head and force a SACK, since we are shutting down. */ 3350 3351 /* Implementor's Guide. 3352 * 3353 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3354 * respond to each received packet containing one or more DATA chunk(s) 3355 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3356 */ 3357 if (chunk->end_of_packet) { 3358 /* We must delay the chunk creation since the cumulative 3359 * TSN has not been updated yet. 3360 */ 3361 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3362 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3363 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3364 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3365 } 3366 3367 return SCTP_DISPOSITION_CONSUME; 3368 } 3369 3370 /* 3371 * Section: 6.2 Processing a Received SACK 3372 * D) Any time a SACK arrives, the endpoint performs the following: 3373 * 3374 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3375 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3376 * increasing, a SACK whose Cumulative TSN Ack is less than the 3377 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3378 * 3379 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3380 * of bytes still outstanding after processing the Cumulative TSN Ack 3381 * and the Gap Ack Blocks. 3382 * 3383 * iii) If the SACK is missing a TSN that was previously 3384 * acknowledged via a Gap Ack Block (e.g., the data receiver 3385 * reneged on the data), then mark the corresponding DATA chunk 3386 * as available for retransmit: Mark it as missing for fast 3387 * retransmit as described in Section 7.2.4 and if no retransmit 3388 * timer is running for the destination address to which the DATA 3389 * chunk was originally transmitted, then T3-rtx is started for 3390 * that destination address. 3391 * 3392 * Verification Tag: 8.5 Verification Tag [Normal verification] 3393 * 3394 * Inputs 3395 * (endpoint, asoc, chunk) 3396 * 3397 * Outputs 3398 * (asoc, reply_msg, msg_up, timers, counters) 3399 * 3400 * The return value is the disposition of the chunk. 3401 */ 3402 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3403 const struct sctp_endpoint *ep, 3404 const struct sctp_association *asoc, 3405 const union sctp_subtype type, 3406 void *arg, 3407 struct sctp_cmd_seq *commands) 3408 { 3409 struct sctp_chunk *chunk = arg; 3410 struct sctp_sackhdr *sackh; 3411 __u32 ctsn; 3412 3413 if (!sctp_vtag_verify(chunk, asoc)) 3414 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3415 3416 /* Make sure that the SACK chunk has a valid length. */ 3417 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3418 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3419 commands); 3420 3421 /* Pull the SACK chunk from the data buffer */ 3422 sackh = sctp_sm_pull_sack(chunk); 3423 /* Was this a bogus SACK? */ 3424 if (!sackh) 3425 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3426 chunk->subh.sack_hdr = sackh; 3427 ctsn = ntohl(sackh->cum_tsn_ack); 3428 3429 /* If Cumulative TSN Ack beyond the max tsn currently 3430 * send, terminating the association and respond to the 3431 * sender with an ABORT. 3432 */ 3433 if (TSN_lte(asoc->next_tsn, ctsn)) 3434 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3435 3436 trace_sctp_probe(ep, asoc, chunk); 3437 3438 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3439 * Ack Point, then drop the SACK. Since Cumulative TSN 3440 * Ack is monotonically increasing, a SACK whose 3441 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3442 * Point indicates an out-of-order SACK. 3443 */ 3444 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3445 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3446 asoc->ctsn_ack_point); 3447 3448 return SCTP_DISPOSITION_DISCARD; 3449 } 3450 3451 /* Return this SACK for further processing. */ 3452 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3453 3454 /* Note: We do the rest of the work on the PROCESS_SACK 3455 * sideeffect. 3456 */ 3457 return SCTP_DISPOSITION_CONSUME; 3458 } 3459 3460 /* 3461 * Generate an ABORT in response to a packet. 3462 * 3463 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3464 * 3465 * 8) The receiver should respond to the sender of the OOTB packet with 3466 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3467 * MUST fill in the Verification Tag field of the outbound packet 3468 * with the value found in the Verification Tag field of the OOTB 3469 * packet and set the T-bit in the Chunk Flags to indicate that the 3470 * Verification Tag is reflected. After sending this ABORT, the 3471 * receiver of the OOTB packet shall discard the OOTB packet and take 3472 * no further action. 3473 * 3474 * Verification Tag: 3475 * 3476 * The return value is the disposition of the chunk. 3477 */ 3478 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3479 struct net *net, 3480 const struct sctp_endpoint *ep, 3481 const struct sctp_association *asoc, 3482 const union sctp_subtype type, 3483 void *arg, 3484 struct sctp_cmd_seq *commands) 3485 { 3486 struct sctp_packet *packet = NULL; 3487 struct sctp_chunk *chunk = arg; 3488 struct sctp_chunk *abort; 3489 3490 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3491 if (!packet) 3492 return SCTP_DISPOSITION_NOMEM; 3493 3494 /* Make an ABORT. The T bit will be set if the asoc 3495 * is NULL. 3496 */ 3497 abort = sctp_make_abort(asoc, chunk, 0); 3498 if (!abort) { 3499 sctp_ootb_pkt_free(packet); 3500 return SCTP_DISPOSITION_NOMEM; 3501 } 3502 3503 /* Reflect vtag if T-Bit is set */ 3504 if (sctp_test_T_bit(abort)) 3505 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3506 3507 /* Set the skb to the belonging sock for accounting. */ 3508 abort->skb->sk = ep->base.sk; 3509 3510 sctp_packet_append_chunk(packet, abort); 3511 3512 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3513 3514 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3515 3516 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3517 return SCTP_DISPOSITION_CONSUME; 3518 } 3519 3520 /* Handling of SCTP Packets Containing an INIT Chunk Matching an 3521 * Existing Associations when the UDP encap port is incorrect. 3522 * 3523 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3524 */ 3525 static enum sctp_disposition sctp_sf_new_encap_port( 3526 struct net *net, 3527 const struct sctp_endpoint *ep, 3528 const struct sctp_association *asoc, 3529 const union sctp_subtype type, 3530 void *arg, 3531 struct sctp_cmd_seq *commands) 3532 { 3533 struct sctp_packet *packet = NULL; 3534 struct sctp_chunk *chunk = arg; 3535 struct sctp_chunk *abort; 3536 3537 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3538 if (!packet) 3539 return SCTP_DISPOSITION_NOMEM; 3540 3541 abort = sctp_make_new_encap_port(asoc, chunk); 3542 if (!abort) { 3543 sctp_ootb_pkt_free(packet); 3544 return SCTP_DISPOSITION_NOMEM; 3545 } 3546 3547 abort->skb->sk = ep->base.sk; 3548 3549 sctp_packet_append_chunk(packet, abort); 3550 3551 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3552 SCTP_PACKET(packet)); 3553 3554 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3555 3556 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3557 return SCTP_DISPOSITION_CONSUME; 3558 } 3559 3560 /* 3561 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3562 * event as ULP notification for each cause included in the chunk. 3563 * 3564 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3565 * 3566 * The return value is the disposition of the chunk. 3567 */ 3568 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3569 const struct sctp_endpoint *ep, 3570 const struct sctp_association *asoc, 3571 const union sctp_subtype type, 3572 void *arg, 3573 struct sctp_cmd_seq *commands) 3574 { 3575 struct sctp_chunk *chunk = arg; 3576 struct sctp_errhdr *err; 3577 3578 if (!sctp_vtag_verify(chunk, asoc)) 3579 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3580 3581 /* Make sure that the ERROR chunk has a valid length. */ 3582 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3583 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3584 commands); 3585 sctp_walk_errors(err, chunk->chunk_hdr); 3586 if ((void *)err != (void *)chunk->chunk_end) 3587 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3588 (void *)err, commands); 3589 3590 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3591 SCTP_CHUNK(chunk)); 3592 3593 return SCTP_DISPOSITION_CONSUME; 3594 } 3595 3596 /* 3597 * Process an inbound SHUTDOWN ACK. 3598 * 3599 * From Section 9.2: 3600 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3601 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3602 * peer, and remove all record of the association. 3603 * 3604 * The return value is the disposition. 3605 */ 3606 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3607 const struct sctp_endpoint *ep, 3608 const struct sctp_association *asoc, 3609 const union sctp_subtype type, 3610 void *arg, 3611 struct sctp_cmd_seq *commands) 3612 { 3613 struct sctp_chunk *chunk = arg; 3614 struct sctp_chunk *reply; 3615 struct sctp_ulpevent *ev; 3616 3617 if (!sctp_vtag_verify(chunk, asoc)) 3618 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3619 3620 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3621 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3622 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3623 commands); 3624 /* 10.2 H) SHUTDOWN COMPLETE notification 3625 * 3626 * When SCTP completes the shutdown procedures (section 9.2) this 3627 * notification is passed to the upper layer. 3628 */ 3629 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3630 0, 0, 0, NULL, GFP_ATOMIC); 3631 if (!ev) 3632 goto nomem; 3633 3634 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3635 reply = sctp_make_shutdown_complete(asoc, chunk); 3636 if (!reply) 3637 goto nomem_chunk; 3638 3639 /* Do all the commands now (after allocation), so that we 3640 * have consistent state if memory allocation fails 3641 */ 3642 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3643 3644 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3645 * stop the T2-shutdown timer, 3646 */ 3647 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3648 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3649 3650 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3651 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3652 3653 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3654 SCTP_STATE(SCTP_STATE_CLOSED)); 3655 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3656 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3657 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3658 3659 /* ...and remove all record of the association. */ 3660 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3661 return SCTP_DISPOSITION_DELETE_TCB; 3662 3663 nomem_chunk: 3664 sctp_ulpevent_free(ev); 3665 nomem: 3666 return SCTP_DISPOSITION_NOMEM; 3667 } 3668 3669 /* 3670 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3671 * 3672 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3673 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3674 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3675 * packet must fill in the Verification Tag field of the outbound 3676 * packet with the Verification Tag received in the SHUTDOWN ACK and 3677 * set the T-bit in the Chunk Flags to indicate that the Verification 3678 * Tag is reflected. 3679 * 3680 * 8) The receiver should respond to the sender of the OOTB packet with 3681 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3682 * MUST fill in the Verification Tag field of the outbound packet 3683 * with the value found in the Verification Tag field of the OOTB 3684 * packet and set the T-bit in the Chunk Flags to indicate that the 3685 * Verification Tag is reflected. After sending this ABORT, the 3686 * receiver of the OOTB packet shall discard the OOTB packet and take 3687 * no further action. 3688 */ 3689 enum sctp_disposition sctp_sf_ootb(struct net *net, 3690 const struct sctp_endpoint *ep, 3691 const struct sctp_association *asoc, 3692 const union sctp_subtype type, 3693 void *arg, struct sctp_cmd_seq *commands) 3694 { 3695 struct sctp_chunk *chunk = arg; 3696 struct sk_buff *skb = chunk->skb; 3697 struct sctp_chunkhdr *ch; 3698 struct sctp_errhdr *err; 3699 int ootb_cookie_ack = 0; 3700 int ootb_shut_ack = 0; 3701 __u8 *ch_end; 3702 3703 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3704 3705 if (asoc && !sctp_vtag_verify(chunk, asoc)) 3706 asoc = NULL; 3707 3708 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3709 do { 3710 /* Report violation if the chunk is less then minimal */ 3711 if (ntohs(ch->length) < sizeof(*ch)) 3712 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3713 commands); 3714 3715 /* Report violation if chunk len overflows */ 3716 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3717 if (ch_end > skb_tail_pointer(skb)) 3718 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3719 commands); 3720 3721 /* Now that we know we at least have a chunk header, 3722 * do things that are type appropriate. 3723 */ 3724 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3725 ootb_shut_ack = 1; 3726 3727 /* RFC 2960, Section 3.3.7 3728 * Moreover, under any circumstances, an endpoint that 3729 * receives an ABORT MUST NOT respond to that ABORT by 3730 * sending an ABORT of its own. 3731 */ 3732 if (SCTP_CID_ABORT == ch->type) 3733 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3734 3735 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3736 * or a COOKIE ACK the SCTP Packet should be silently 3737 * discarded. 3738 */ 3739 3740 if (SCTP_CID_COOKIE_ACK == ch->type) 3741 ootb_cookie_ack = 1; 3742 3743 if (SCTP_CID_ERROR == ch->type) { 3744 sctp_walk_errors(err, ch) { 3745 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3746 ootb_cookie_ack = 1; 3747 break; 3748 } 3749 } 3750 } 3751 3752 ch = (struct sctp_chunkhdr *)ch_end; 3753 } while (ch_end < skb_tail_pointer(skb)); 3754 3755 if (ootb_shut_ack) 3756 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3757 else if (ootb_cookie_ack) 3758 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3759 else 3760 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3761 } 3762 3763 /* 3764 * Handle an "Out of the blue" SHUTDOWN ACK. 3765 * 3766 * Section: 8.4 5, sctpimpguide 2.41. 3767 * 3768 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3769 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3770 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3771 * packet must fill in the Verification Tag field of the outbound 3772 * packet with the Verification Tag received in the SHUTDOWN ACK and 3773 * set the T-bit in the Chunk Flags to indicate that the Verification 3774 * Tag is reflected. 3775 * 3776 * Inputs 3777 * (endpoint, asoc, type, arg, commands) 3778 * 3779 * Outputs 3780 * (enum sctp_disposition) 3781 * 3782 * The return value is the disposition of the chunk. 3783 */ 3784 static enum sctp_disposition sctp_sf_shut_8_4_5( 3785 struct net *net, 3786 const struct sctp_endpoint *ep, 3787 const struct sctp_association *asoc, 3788 const union sctp_subtype type, 3789 void *arg, 3790 struct sctp_cmd_seq *commands) 3791 { 3792 struct sctp_packet *packet = NULL; 3793 struct sctp_chunk *chunk = arg; 3794 struct sctp_chunk *shut; 3795 3796 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3797 if (!packet) 3798 return SCTP_DISPOSITION_NOMEM; 3799 3800 /* Make an SHUTDOWN_COMPLETE. 3801 * The T bit will be set if the asoc is NULL. 3802 */ 3803 shut = sctp_make_shutdown_complete(asoc, chunk); 3804 if (!shut) { 3805 sctp_ootb_pkt_free(packet); 3806 return SCTP_DISPOSITION_NOMEM; 3807 } 3808 3809 /* Reflect vtag if T-Bit is set */ 3810 if (sctp_test_T_bit(shut)) 3811 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3812 3813 /* Set the skb to the belonging sock for accounting. */ 3814 shut->skb->sk = ep->base.sk; 3815 3816 sctp_packet_append_chunk(packet, shut); 3817 3818 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3819 SCTP_PACKET(packet)); 3820 3821 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3822 3823 /* We need to discard the rest of the packet to prevent 3824 * potential boomming attacks from additional bundled chunks. 3825 * This is documented in SCTP Threats ID. 3826 */ 3827 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3828 } 3829 3830 /* 3831 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3832 * 3833 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3834 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3835 * procedures in section 8.4 SHOULD be followed, in other words it 3836 * should be treated as an Out Of The Blue packet. 3837 * [This means that we do NOT check the Verification Tag on these 3838 * chunks. --piggy ] 3839 * 3840 */ 3841 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3842 const struct sctp_endpoint *ep, 3843 const struct sctp_association *asoc, 3844 const union sctp_subtype type, 3845 void *arg, 3846 struct sctp_cmd_seq *commands) 3847 { 3848 struct sctp_chunk *chunk = arg; 3849 3850 if (!sctp_vtag_verify(chunk, asoc)) 3851 asoc = NULL; 3852 3853 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3854 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3855 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3856 commands); 3857 3858 /* Although we do have an association in this case, it corresponds 3859 * to a restarted association. So the packet is treated as an OOTB 3860 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3861 * called with a NULL association. 3862 */ 3863 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3864 3865 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3866 } 3867 3868 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3869 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3870 const struct sctp_endpoint *ep, 3871 const struct sctp_association *asoc, 3872 const union sctp_subtype type, 3873 void *arg, 3874 struct sctp_cmd_seq *commands) 3875 { 3876 struct sctp_paramhdr *err_param = NULL; 3877 struct sctp_chunk *asconf_ack = NULL; 3878 struct sctp_chunk *chunk = arg; 3879 struct sctp_addiphdr *hdr; 3880 __u32 serial; 3881 3882 if (!sctp_vtag_verify(chunk, asoc)) { 3883 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3884 SCTP_NULL()); 3885 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3886 } 3887 3888 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3889 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3890 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3891 commands); 3892 3893 /* ADD-IP: Section 4.1.1 3894 * This chunk MUST be sent in an authenticated way by using 3895 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3896 * is received unauthenticated it MUST be silently discarded as 3897 * described in [I-D.ietf-tsvwg-sctp-auth]. 3898 */ 3899 if (!asoc->peer.asconf_capable || 3900 (!net->sctp.addip_noauth && !chunk->auth)) 3901 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3902 3903 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3904 serial = ntohl(hdr->serial); 3905 3906 /* Verify the ASCONF chunk before processing it. */ 3907 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3908 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3909 (void *)err_param, commands); 3910 3911 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3912 * the endpoint stored in a new association variable 3913 * 'Peer-Serial-Number'. 3914 */ 3915 if (serial == asoc->peer.addip_serial + 1) { 3916 /* If this is the first instance of ASCONF in the packet, 3917 * we can clean our old ASCONF-ACKs. 3918 */ 3919 if (!chunk->has_asconf) 3920 sctp_assoc_clean_asconf_ack_cache(asoc); 3921 3922 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3923 * expected, process the ASCONF as described below and after 3924 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3925 * the response packet and cache a copy of it (in the event it 3926 * later needs to be retransmitted). 3927 * 3928 * Essentially, do V1-V5. 3929 */ 3930 asconf_ack = sctp_process_asconf((struct sctp_association *) 3931 asoc, chunk); 3932 if (!asconf_ack) 3933 return SCTP_DISPOSITION_NOMEM; 3934 } else if (serial < asoc->peer.addip_serial + 1) { 3935 /* ADDIP 5.2 E2) 3936 * If the value found in the Sequence Number is less than the 3937 * ('Peer- Sequence-Number' + 1), simply skip to the next 3938 * ASCONF, and include in the outbound response packet 3939 * any previously cached ASCONF-ACK response that was 3940 * sent and saved that matches the Sequence Number of the 3941 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3942 * Chunk exists. This will occur when an older ASCONF 3943 * arrives out of order. In such a case, the receiver 3944 * should skip the ASCONF Chunk and not include ASCONF-ACK 3945 * Chunk for that chunk. 3946 */ 3947 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3948 if (!asconf_ack) 3949 return SCTP_DISPOSITION_DISCARD; 3950 3951 /* Reset the transport so that we select the correct one 3952 * this time around. This is to make sure that we don't 3953 * accidentally use a stale transport that's been removed. 3954 */ 3955 asconf_ack->transport = NULL; 3956 } else { 3957 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3958 * it must be either a stale packet or from an attacker. 3959 */ 3960 return SCTP_DISPOSITION_DISCARD; 3961 } 3962 3963 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3964 * containing the ASCONF-ACK Chunks MUST be the source address of 3965 * the SCTP packet that held the ASCONF Chunks. 3966 * 3967 * To do this properly, we'll set the destination address of the chunk 3968 * and at the transmit time, will try look up the transport to use. 3969 * Since ASCONFs may be bundled, the correct transport may not be 3970 * created until we process the entire packet, thus this workaround. 3971 */ 3972 asconf_ack->dest = chunk->source; 3973 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3974 if (asoc->new_transport) { 3975 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3976 ((struct sctp_association *)asoc)->new_transport = NULL; 3977 } 3978 3979 return SCTP_DISPOSITION_CONSUME; 3980 } 3981 3982 static enum sctp_disposition sctp_send_next_asconf( 3983 struct net *net, 3984 const struct sctp_endpoint *ep, 3985 struct sctp_association *asoc, 3986 const union sctp_subtype type, 3987 struct sctp_cmd_seq *commands) 3988 { 3989 struct sctp_chunk *asconf; 3990 struct list_head *entry; 3991 3992 if (list_empty(&asoc->addip_chunk_list)) 3993 return SCTP_DISPOSITION_CONSUME; 3994 3995 entry = asoc->addip_chunk_list.next; 3996 asconf = list_entry(entry, struct sctp_chunk, list); 3997 3998 list_del_init(entry); 3999 sctp_chunk_hold(asconf); 4000 asoc->addip_last_asconf = asconf; 4001 4002 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 4003 } 4004 4005 /* 4006 * ADDIP Section 4.3 General rules for address manipulation 4007 * When building TLV parameters for the ASCONF Chunk that will add or 4008 * delete IP addresses the D0 to D13 rules should be applied: 4009 */ 4010 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 4011 const struct sctp_endpoint *ep, 4012 const struct sctp_association *asoc, 4013 const union sctp_subtype type, 4014 void *arg, 4015 struct sctp_cmd_seq *commands) 4016 { 4017 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 4018 struct sctp_paramhdr *err_param = NULL; 4019 struct sctp_chunk *asconf_ack = arg; 4020 struct sctp_addiphdr *addip_hdr; 4021 __u32 sent_serial, rcvd_serial; 4022 struct sctp_chunk *abort; 4023 4024 if (!sctp_vtag_verify(asconf_ack, asoc)) { 4025 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4026 SCTP_NULL()); 4027 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4028 } 4029 4030 /* Make sure that the ADDIP chunk has a valid length. */ 4031 if (!sctp_chunk_length_valid(asconf_ack, 4032 sizeof(struct sctp_addip_chunk))) 4033 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4034 commands); 4035 4036 /* ADD-IP, Section 4.1.2: 4037 * This chunk MUST be sent in an authenticated way by using 4038 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 4039 * is received unauthenticated it MUST be silently discarded as 4040 * described in [I-D.ietf-tsvwg-sctp-auth]. 4041 */ 4042 if (!asoc->peer.asconf_capable || 4043 (!net->sctp.addip_noauth && !asconf_ack->auth)) 4044 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4045 4046 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 4047 rcvd_serial = ntohl(addip_hdr->serial); 4048 4049 /* Verify the ASCONF-ACK chunk before processing it. */ 4050 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 4051 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4052 (void *)err_param, commands); 4053 4054 if (last_asconf) { 4055 addip_hdr = last_asconf->subh.addip_hdr; 4056 sent_serial = ntohl(addip_hdr->serial); 4057 } else { 4058 sent_serial = asoc->addip_serial - 1; 4059 } 4060 4061 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 4062 * equal to the next serial number to be used but no ASCONF chunk is 4063 * outstanding the endpoint MUST ABORT the association. Note that a 4064 * sequence number is greater than if it is no more than 2^^31-1 4065 * larger than the current sequence number (using serial arithmetic). 4066 */ 4067 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 4068 !(asoc->addip_last_asconf)) { 4069 abort = sctp_make_abort(asoc, asconf_ack, 4070 sizeof(struct sctp_errhdr)); 4071 if (abort) { 4072 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 4073 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4074 SCTP_CHUNK(abort)); 4075 } 4076 /* We are going to ABORT, so we might as well stop 4077 * processing the rest of the chunks in the packet. 4078 */ 4079 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4080 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4081 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4082 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4083 SCTP_ERROR(ECONNABORTED)); 4084 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4085 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4086 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4087 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4088 return SCTP_DISPOSITION_ABORT; 4089 } 4090 4091 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4092 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4093 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4094 4095 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4096 asconf_ack)) 4097 return sctp_send_next_asconf(net, ep, 4098 (struct sctp_association *)asoc, 4099 type, commands); 4100 4101 abort = sctp_make_abort(asoc, asconf_ack, 4102 sizeof(struct sctp_errhdr)); 4103 if (abort) { 4104 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4105 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4106 SCTP_CHUNK(abort)); 4107 } 4108 /* We are going to ABORT, so we might as well stop 4109 * processing the rest of the chunks in the packet. 4110 */ 4111 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4112 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4113 SCTP_ERROR(ECONNABORTED)); 4114 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4115 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4116 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4117 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4118 return SCTP_DISPOSITION_ABORT; 4119 } 4120 4121 return SCTP_DISPOSITION_DISCARD; 4122 } 4123 4124 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4125 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4126 const struct sctp_endpoint *ep, 4127 const struct sctp_association *asoc, 4128 const union sctp_subtype type, 4129 void *arg, 4130 struct sctp_cmd_seq *commands) 4131 { 4132 struct sctp_paramhdr *err_param = NULL; 4133 struct sctp_chunk *chunk = arg; 4134 struct sctp_reconf_chunk *hdr; 4135 union sctp_params param; 4136 4137 if (!sctp_vtag_verify(chunk, asoc)) { 4138 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4139 SCTP_NULL()); 4140 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4141 } 4142 4143 /* Make sure that the RECONF chunk has a valid length. */ 4144 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4145 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4146 commands); 4147 4148 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4149 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4150 (void *)err_param, commands); 4151 4152 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4153 sctp_walk_params(param, hdr) { 4154 struct sctp_chunk *reply = NULL; 4155 struct sctp_ulpevent *ev = NULL; 4156 4157 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4158 reply = sctp_process_strreset_outreq( 4159 (struct sctp_association *)asoc, param, &ev); 4160 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4161 reply = sctp_process_strreset_inreq( 4162 (struct sctp_association *)asoc, param, &ev); 4163 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4164 reply = sctp_process_strreset_tsnreq( 4165 (struct sctp_association *)asoc, param, &ev); 4166 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4167 reply = sctp_process_strreset_addstrm_out( 4168 (struct sctp_association *)asoc, param, &ev); 4169 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4170 reply = sctp_process_strreset_addstrm_in( 4171 (struct sctp_association *)asoc, param, &ev); 4172 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4173 reply = sctp_process_strreset_resp( 4174 (struct sctp_association *)asoc, param, &ev); 4175 4176 if (ev) 4177 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4178 SCTP_ULPEVENT(ev)); 4179 4180 if (reply) 4181 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4182 SCTP_CHUNK(reply)); 4183 } 4184 4185 return SCTP_DISPOSITION_CONSUME; 4186 } 4187 4188 /* 4189 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4190 * 4191 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4192 * its cumulative TSN point to the value carried in the FORWARD TSN 4193 * chunk, and then MUST further advance its cumulative TSN point locally 4194 * if possible. 4195 * After the above processing, the data receiver MUST stop reporting any 4196 * missing TSNs earlier than or equal to the new cumulative TSN point. 4197 * 4198 * Verification Tag: 8.5 Verification Tag [Normal verification] 4199 * 4200 * The return value is the disposition of the chunk. 4201 */ 4202 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4203 const struct sctp_endpoint *ep, 4204 const struct sctp_association *asoc, 4205 const union sctp_subtype type, 4206 void *arg, 4207 struct sctp_cmd_seq *commands) 4208 { 4209 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4210 struct sctp_chunk *chunk = arg; 4211 __u16 len; 4212 __u32 tsn; 4213 4214 if (!sctp_vtag_verify(chunk, asoc)) { 4215 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4216 SCTP_NULL()); 4217 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4218 } 4219 4220 if (!asoc->peer.prsctp_capable) 4221 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4222 4223 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4224 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4225 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4226 commands); 4227 4228 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4229 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4230 len = ntohs(chunk->chunk_hdr->length); 4231 len -= sizeof(struct sctp_chunkhdr); 4232 skb_pull(chunk->skb, len); 4233 4234 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4235 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4236 4237 /* The TSN is too high--silently discard the chunk and count on it 4238 * getting retransmitted later. 4239 */ 4240 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4241 goto discard_noforce; 4242 4243 if (!asoc->stream.si->validate_ftsn(chunk)) 4244 goto discard_noforce; 4245 4246 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4247 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4248 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4249 SCTP_CHUNK(chunk)); 4250 4251 /* Count this as receiving DATA. */ 4252 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4254 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4255 } 4256 4257 /* FIXME: For now send a SACK, but DATA processing may 4258 * send another. 4259 */ 4260 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4261 4262 return SCTP_DISPOSITION_CONSUME; 4263 4264 discard_noforce: 4265 return SCTP_DISPOSITION_DISCARD; 4266 } 4267 4268 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4269 struct net *net, 4270 const struct sctp_endpoint *ep, 4271 const struct sctp_association *asoc, 4272 const union sctp_subtype type, 4273 void *arg, 4274 struct sctp_cmd_seq *commands) 4275 { 4276 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4277 struct sctp_chunk *chunk = arg; 4278 __u16 len; 4279 __u32 tsn; 4280 4281 if (!sctp_vtag_verify(chunk, asoc)) { 4282 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4283 SCTP_NULL()); 4284 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4285 } 4286 4287 if (!asoc->peer.prsctp_capable) 4288 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4289 4290 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4291 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4292 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4293 commands); 4294 4295 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4296 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4297 len = ntohs(chunk->chunk_hdr->length); 4298 len -= sizeof(struct sctp_chunkhdr); 4299 skb_pull(chunk->skb, len); 4300 4301 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4302 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4303 4304 /* The TSN is too high--silently discard the chunk and count on it 4305 * getting retransmitted later. 4306 */ 4307 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4308 goto gen_shutdown; 4309 4310 if (!asoc->stream.si->validate_ftsn(chunk)) 4311 goto gen_shutdown; 4312 4313 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4314 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4315 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4316 SCTP_CHUNK(chunk)); 4317 4318 /* Go a head and force a SACK, since we are shutting down. */ 4319 gen_shutdown: 4320 /* Implementor's Guide. 4321 * 4322 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4323 * respond to each received packet containing one or more DATA chunk(s) 4324 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4325 */ 4326 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4327 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4328 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4329 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4330 4331 return SCTP_DISPOSITION_CONSUME; 4332 } 4333 4334 /* 4335 * SCTP-AUTH Section 6.3 Receiving authenticated chunks 4336 * 4337 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4338 * Identifier field. If this algorithm was not specified by the 4339 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4340 * during association setup, the AUTH chunk and all chunks after it MUST 4341 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4342 * defined in Section 4.1. 4343 * 4344 * If an endpoint with no shared key receives a Shared Key Identifier 4345 * other than 0, it MUST silently discard all authenticated chunks. If 4346 * the endpoint has at least one endpoint pair shared key for the peer, 4347 * it MUST use the key specified by the Shared Key Identifier if a 4348 * key has been configured for that Shared Key Identifier. If no 4349 * endpoint pair shared key has been configured for that Shared Key 4350 * Identifier, all authenticated chunks MUST be silently discarded. 4351 * 4352 * Verification Tag: 8.5 Verification Tag [Normal verification] 4353 * 4354 * The return value is the disposition of the chunk. 4355 */ 4356 static enum sctp_ierror sctp_sf_authenticate( 4357 const struct sctp_association *asoc, 4358 struct sctp_chunk *chunk) 4359 { 4360 struct sctp_shared_key *sh_key = NULL; 4361 struct sctp_authhdr *auth_hdr; 4362 __u8 *save_digest, *digest; 4363 struct sctp_hmac *hmac; 4364 unsigned int sig_len; 4365 __u16 key_id; 4366 4367 /* Pull in the auth header, so we can do some more verification */ 4368 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4369 chunk->subh.auth_hdr = auth_hdr; 4370 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4371 4372 /* Make sure that we support the HMAC algorithm from the auth 4373 * chunk. 4374 */ 4375 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4376 return SCTP_IERROR_AUTH_BAD_HMAC; 4377 4378 /* Make sure that the provided shared key identifier has been 4379 * configured 4380 */ 4381 key_id = ntohs(auth_hdr->shkey_id); 4382 if (key_id != asoc->active_key_id) { 4383 sh_key = sctp_auth_get_shkey(asoc, key_id); 4384 if (!sh_key) 4385 return SCTP_IERROR_AUTH_BAD_KEYID; 4386 } 4387 4388 /* Make sure that the length of the signature matches what 4389 * we expect. 4390 */ 4391 sig_len = ntohs(chunk->chunk_hdr->length) - 4392 sizeof(struct sctp_auth_chunk); 4393 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4394 if (sig_len != hmac->hmac_len) 4395 return SCTP_IERROR_PROTO_VIOLATION; 4396 4397 /* Now that we've done validation checks, we can compute and 4398 * verify the hmac. The steps involved are: 4399 * 1. Save the digest from the chunk. 4400 * 2. Zero out the digest in the chunk. 4401 * 3. Compute the new digest 4402 * 4. Compare saved and new digests. 4403 */ 4404 digest = (u8 *)(auth_hdr + 1); 4405 skb_pull(chunk->skb, sig_len); 4406 4407 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4408 if (!save_digest) 4409 goto nomem; 4410 4411 memset(digest, 0, sig_len); 4412 4413 sctp_auth_calculate_hmac(asoc, chunk->skb, 4414 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4415 sh_key, GFP_ATOMIC); 4416 4417 /* Discard the packet if the digests do not match */ 4418 if (memcmp(save_digest, digest, sig_len)) { 4419 kfree(save_digest); 4420 return SCTP_IERROR_BAD_SIG; 4421 } 4422 4423 kfree(save_digest); 4424 chunk->auth = 1; 4425 4426 return SCTP_IERROR_NO_ERROR; 4427 nomem: 4428 return SCTP_IERROR_NOMEM; 4429 } 4430 4431 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4432 const struct sctp_endpoint *ep, 4433 const struct sctp_association *asoc, 4434 const union sctp_subtype type, 4435 void *arg, struct sctp_cmd_seq *commands) 4436 { 4437 struct sctp_chunk *chunk = arg; 4438 struct sctp_authhdr *auth_hdr; 4439 struct sctp_chunk *err_chunk; 4440 enum sctp_ierror error; 4441 4442 /* Make sure that the peer has AUTH capable */ 4443 if (!asoc->peer.auth_capable) 4444 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4445 4446 if (!sctp_vtag_verify(chunk, asoc)) { 4447 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4448 SCTP_NULL()); 4449 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4450 } 4451 4452 /* Make sure that the AUTH chunk has valid length. */ 4453 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4454 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4455 commands); 4456 4457 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4458 error = sctp_sf_authenticate(asoc, chunk); 4459 switch (error) { 4460 case SCTP_IERROR_AUTH_BAD_HMAC: 4461 /* Generate the ERROR chunk and discard the rest 4462 * of the packet 4463 */ 4464 err_chunk = sctp_make_op_error(asoc, chunk, 4465 SCTP_ERROR_UNSUP_HMAC, 4466 &auth_hdr->hmac_id, 4467 sizeof(__u16), 0); 4468 if (err_chunk) { 4469 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4470 SCTP_CHUNK(err_chunk)); 4471 } 4472 fallthrough; 4473 case SCTP_IERROR_AUTH_BAD_KEYID: 4474 case SCTP_IERROR_BAD_SIG: 4475 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4476 4477 case SCTP_IERROR_PROTO_VIOLATION: 4478 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4479 commands); 4480 4481 case SCTP_IERROR_NOMEM: 4482 return SCTP_DISPOSITION_NOMEM; 4483 4484 default: /* Prevent gcc warnings */ 4485 break; 4486 } 4487 4488 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4489 struct sctp_ulpevent *ev; 4490 4491 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4492 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4493 4494 if (!ev) 4495 return SCTP_DISPOSITION_NOMEM; 4496 4497 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4498 SCTP_ULPEVENT(ev)); 4499 } 4500 4501 return SCTP_DISPOSITION_CONSUME; 4502 } 4503 4504 /* 4505 * Process an unknown chunk. 4506 * 4507 * Section: 3.2. Also, 2.1 in the implementor's guide. 4508 * 4509 * Chunk Types are encoded such that the highest-order two bits specify 4510 * the action that must be taken if the processing endpoint does not 4511 * recognize the Chunk Type. 4512 * 4513 * 00 - Stop processing this SCTP packet and discard it, do not process 4514 * any further chunks within it. 4515 * 4516 * 01 - Stop processing this SCTP packet and discard it, do not process 4517 * any further chunks within it, and report the unrecognized 4518 * chunk in an 'Unrecognized Chunk Type'. 4519 * 4520 * 10 - Skip this chunk and continue processing. 4521 * 4522 * 11 - Skip this chunk and continue processing, but report in an ERROR 4523 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4524 * 4525 * The return value is the disposition of the chunk. 4526 */ 4527 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4528 const struct sctp_endpoint *ep, 4529 const struct sctp_association *asoc, 4530 const union sctp_subtype type, 4531 void *arg, 4532 struct sctp_cmd_seq *commands) 4533 { 4534 struct sctp_chunk *unk_chunk = arg; 4535 struct sctp_chunk *err_chunk; 4536 struct sctp_chunkhdr *hdr; 4537 4538 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4539 4540 if (!sctp_vtag_verify(unk_chunk, asoc)) 4541 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4542 4543 /* Make sure that the chunk has a valid length. 4544 * Since we don't know the chunk type, we use a general 4545 * chunkhdr structure to make a comparison. 4546 */ 4547 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4548 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4549 commands); 4550 4551 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4552 case SCTP_CID_ACTION_DISCARD: 4553 /* Discard the packet. */ 4554 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4555 case SCTP_CID_ACTION_DISCARD_ERR: 4556 /* Generate an ERROR chunk as response. */ 4557 hdr = unk_chunk->chunk_hdr; 4558 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4559 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4560 SCTP_PAD4(ntohs(hdr->length)), 4561 0); 4562 if (err_chunk) { 4563 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4564 SCTP_CHUNK(err_chunk)); 4565 } 4566 4567 /* Discard the packet. */ 4568 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4569 return SCTP_DISPOSITION_CONSUME; 4570 case SCTP_CID_ACTION_SKIP: 4571 /* Skip the chunk. */ 4572 return SCTP_DISPOSITION_DISCARD; 4573 case SCTP_CID_ACTION_SKIP_ERR: 4574 /* Generate an ERROR chunk as response. */ 4575 hdr = unk_chunk->chunk_hdr; 4576 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4577 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4578 SCTP_PAD4(ntohs(hdr->length)), 4579 0); 4580 if (err_chunk) { 4581 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4582 SCTP_CHUNK(err_chunk)); 4583 } 4584 /* Skip the chunk. */ 4585 return SCTP_DISPOSITION_CONSUME; 4586 default: 4587 break; 4588 } 4589 4590 return SCTP_DISPOSITION_DISCARD; 4591 } 4592 4593 /* 4594 * Discard the chunk. 4595 * 4596 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4597 * [Too numerous to mention...] 4598 * Verification Tag: No verification needed. 4599 * Inputs 4600 * (endpoint, asoc, chunk) 4601 * 4602 * Outputs 4603 * (asoc, reply_msg, msg_up, timers, counters) 4604 * 4605 * The return value is the disposition of the chunk. 4606 */ 4607 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4608 const struct sctp_endpoint *ep, 4609 const struct sctp_association *asoc, 4610 const union sctp_subtype type, 4611 void *arg, 4612 struct sctp_cmd_seq *commands) 4613 { 4614 struct sctp_chunk *chunk = arg; 4615 4616 if (asoc && !sctp_vtag_verify(chunk, asoc)) 4617 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4618 4619 /* Make sure that the chunk has a valid length. 4620 * Since we don't know the chunk type, we use a general 4621 * chunkhdr structure to make a comparison. 4622 */ 4623 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4624 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4625 commands); 4626 4627 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4628 4629 return SCTP_DISPOSITION_DISCARD; 4630 } 4631 4632 /* 4633 * Discard the whole packet. 4634 * 4635 * Section: 8.4 2) 4636 * 4637 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4638 * silently discard the OOTB packet and take no further action. 4639 * 4640 * Verification Tag: No verification necessary 4641 * 4642 * Inputs 4643 * (endpoint, asoc, chunk) 4644 * 4645 * Outputs 4646 * (asoc, reply_msg, msg_up, timers, counters) 4647 * 4648 * The return value is the disposition of the chunk. 4649 */ 4650 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4651 const struct sctp_endpoint *ep, 4652 const struct sctp_association *asoc, 4653 const union sctp_subtype type, 4654 void *arg, struct sctp_cmd_seq *commands) 4655 { 4656 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4657 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4658 4659 return SCTP_DISPOSITION_CONSUME; 4660 } 4661 4662 4663 /* 4664 * The other end is violating protocol. 4665 * 4666 * Section: Not specified 4667 * Verification Tag: Not specified 4668 * Inputs 4669 * (endpoint, asoc, chunk) 4670 * 4671 * Outputs 4672 * (asoc, reply_msg, msg_up, timers, counters) 4673 * 4674 * We simply tag the chunk as a violation. The state machine will log 4675 * the violation and continue. 4676 */ 4677 enum sctp_disposition sctp_sf_violation(struct net *net, 4678 const struct sctp_endpoint *ep, 4679 const struct sctp_association *asoc, 4680 const union sctp_subtype type, 4681 void *arg, 4682 struct sctp_cmd_seq *commands) 4683 { 4684 struct sctp_chunk *chunk = arg; 4685 4686 if (!sctp_vtag_verify(chunk, asoc)) 4687 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4688 4689 /* Make sure that the chunk has a valid length. */ 4690 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4691 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4692 commands); 4693 4694 return SCTP_DISPOSITION_VIOLATION; 4695 } 4696 4697 /* 4698 * Common function to handle a protocol violation. 4699 */ 4700 static enum sctp_disposition sctp_sf_abort_violation( 4701 struct net *net, 4702 const struct sctp_endpoint *ep, 4703 const struct sctp_association *asoc, 4704 void *arg, 4705 struct sctp_cmd_seq *commands, 4706 const __u8 *payload, 4707 const size_t paylen) 4708 { 4709 struct sctp_packet *packet = NULL; 4710 struct sctp_chunk *chunk = arg; 4711 struct sctp_chunk *abort = NULL; 4712 4713 /* SCTP-AUTH, Section 6.3: 4714 * It should be noted that if the receiver wants to tear 4715 * down an association in an authenticated way only, the 4716 * handling of malformed packets should not result in 4717 * tearing down the association. 4718 * 4719 * This means that if we only want to abort associations 4720 * in an authenticated way (i.e AUTH+ABORT), then we 4721 * can't destroy this association just because the packet 4722 * was malformed. 4723 */ 4724 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4725 goto discard; 4726 4727 /* Make the abort chunk. */ 4728 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4729 if (!abort) 4730 goto nomem; 4731 4732 if (asoc) { 4733 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4734 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4735 !asoc->peer.i.init_tag) { 4736 struct sctp_initack_chunk *initack; 4737 4738 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4739 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4740 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4741 else { 4742 unsigned int inittag; 4743 4744 inittag = ntohl(initack->init_hdr.init_tag); 4745 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4746 SCTP_U32(inittag)); 4747 } 4748 } 4749 4750 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4751 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4752 4753 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4754 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4755 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4756 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4757 SCTP_ERROR(ECONNREFUSED)); 4758 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4759 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4760 } else { 4761 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4762 SCTP_ERROR(ECONNABORTED)); 4763 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4764 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4765 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4766 } 4767 } else { 4768 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4769 4770 if (!packet) 4771 goto nomem_pkt; 4772 4773 if (sctp_test_T_bit(abort)) 4774 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4775 4776 abort->skb->sk = ep->base.sk; 4777 4778 sctp_packet_append_chunk(packet, abort); 4779 4780 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4781 SCTP_PACKET(packet)); 4782 4783 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4784 } 4785 4786 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4787 4788 discard: 4789 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4790 return SCTP_DISPOSITION_ABORT; 4791 4792 nomem_pkt: 4793 sctp_chunk_free(abort); 4794 nomem: 4795 return SCTP_DISPOSITION_NOMEM; 4796 } 4797 4798 /* 4799 * Handle a protocol violation when the chunk length is invalid. 4800 * "Invalid" length is identified as smaller than the minimal length a 4801 * given chunk can be. For example, a SACK chunk has invalid length 4802 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4803 * 4804 * We inform the other end by sending an ABORT with a Protocol Violation 4805 * error code. 4806 * 4807 * Section: Not specified 4808 * Verification Tag: Nothing to do 4809 * Inputs 4810 * (endpoint, asoc, chunk) 4811 * 4812 * Outputs 4813 * (reply_msg, msg_up, counters) 4814 * 4815 * Generate an ABORT chunk and terminate the association. 4816 */ 4817 static enum sctp_disposition sctp_sf_violation_chunklen( 4818 struct net *net, 4819 const struct sctp_endpoint *ep, 4820 const struct sctp_association *asoc, 4821 const union sctp_subtype type, 4822 void *arg, 4823 struct sctp_cmd_seq *commands) 4824 { 4825 static const char err_str[] = "The following chunk had invalid length:"; 4826 4827 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4828 sizeof(err_str)); 4829 } 4830 4831 /* 4832 * Handle a protocol violation when the parameter length is invalid. 4833 * If the length is smaller than the minimum length of a given parameter, 4834 * or accumulated length in multi parameters exceeds the end of the chunk, 4835 * the length is considered as invalid. 4836 */ 4837 static enum sctp_disposition sctp_sf_violation_paramlen( 4838 struct net *net, 4839 const struct sctp_endpoint *ep, 4840 const struct sctp_association *asoc, 4841 const union sctp_subtype type, 4842 void *arg, void *ext, 4843 struct sctp_cmd_seq *commands) 4844 { 4845 struct sctp_paramhdr *param = ext; 4846 struct sctp_chunk *abort = NULL; 4847 struct sctp_chunk *chunk = arg; 4848 4849 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4850 goto discard; 4851 4852 /* Make the abort chunk. */ 4853 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4854 if (!abort) 4855 goto nomem; 4856 4857 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4858 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4859 4860 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4861 SCTP_ERROR(ECONNABORTED)); 4862 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4863 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4864 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4865 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4866 4867 discard: 4868 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4869 return SCTP_DISPOSITION_ABORT; 4870 nomem: 4871 return SCTP_DISPOSITION_NOMEM; 4872 } 4873 4874 /* Handle a protocol violation when the peer trying to advance the 4875 * cumulative tsn ack to a point beyond the max tsn currently sent. 4876 * 4877 * We inform the other end by sending an ABORT with a Protocol Violation 4878 * error code. 4879 */ 4880 static enum sctp_disposition sctp_sf_violation_ctsn( 4881 struct net *net, 4882 const struct sctp_endpoint *ep, 4883 const struct sctp_association *asoc, 4884 const union sctp_subtype type, 4885 void *arg, 4886 struct sctp_cmd_seq *commands) 4887 { 4888 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4889 4890 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4891 sizeof(err_str)); 4892 } 4893 4894 /* Handle protocol violation of an invalid chunk bundling. For example, 4895 * when we have an association and we receive bundled INIT-ACK, or 4896 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle" 4897 * statement from the specs. Additionally, there might be an attacker 4898 * on the path and we may not want to continue this communication. 4899 */ 4900 static enum sctp_disposition sctp_sf_violation_chunk( 4901 struct net *net, 4902 const struct sctp_endpoint *ep, 4903 const struct sctp_association *asoc, 4904 const union sctp_subtype type, 4905 void *arg, 4906 struct sctp_cmd_seq *commands) 4907 { 4908 static const char err_str[] = "The following chunk violates protocol:"; 4909 4910 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4911 sizeof(err_str)); 4912 } 4913 /*************************************************************************** 4914 * These are the state functions for handling primitive (Section 10) events. 4915 ***************************************************************************/ 4916 /* 4917 * sctp_sf_do_prm_asoc 4918 * 4919 * Section: 10.1 ULP-to-SCTP 4920 * B) Associate 4921 * 4922 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4923 * outbound stream count) 4924 * -> association id [,destination transport addr list] [,outbound stream 4925 * count] 4926 * 4927 * This primitive allows the upper layer to initiate an association to a 4928 * specific peer endpoint. 4929 * 4930 * The peer endpoint shall be specified by one of the transport addresses 4931 * which defines the endpoint (see Section 1.4). If the local SCTP 4932 * instance has not been initialized, the ASSOCIATE is considered an 4933 * error. 4934 * [This is not relevant for the kernel implementation since we do all 4935 * initialization at boot time. It we hadn't initialized we wouldn't 4936 * get anywhere near this code.] 4937 * 4938 * An association id, which is a local handle to the SCTP association, 4939 * will be returned on successful establishment of the association. If 4940 * SCTP is not able to open an SCTP association with the peer endpoint, 4941 * an error is returned. 4942 * [In the kernel implementation, the struct sctp_association needs to 4943 * be created BEFORE causing this primitive to run.] 4944 * 4945 * Other association parameters may be returned, including the 4946 * complete destination transport addresses of the peer as well as the 4947 * outbound stream count of the local endpoint. One of the transport 4948 * address from the returned destination addresses will be selected by 4949 * the local endpoint as default primary path for sending SCTP packets 4950 * to this peer. The returned "destination transport addr list" can 4951 * be used by the ULP to change the default primary path or to force 4952 * sending a packet to a specific transport address. [All of this 4953 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4954 * function.] 4955 * 4956 * Mandatory attributes: 4957 * 4958 * o local SCTP instance name - obtained from the INITIALIZE operation. 4959 * [This is the argument asoc.] 4960 * o destination transport addr - specified as one of the transport 4961 * addresses of the peer endpoint with which the association is to be 4962 * established. 4963 * [This is asoc->peer.active_path.] 4964 * o outbound stream count - the number of outbound streams the ULP 4965 * would like to open towards this peer endpoint. 4966 * [BUG: This is not currently implemented.] 4967 * Optional attributes: 4968 * 4969 * None. 4970 * 4971 * The return value is a disposition. 4972 */ 4973 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4974 const struct sctp_endpoint *ep, 4975 const struct sctp_association *asoc, 4976 const union sctp_subtype type, 4977 void *arg, 4978 struct sctp_cmd_seq *commands) 4979 { 4980 struct sctp_association *my_asoc; 4981 struct sctp_chunk *repl; 4982 4983 /* The comment below says that we enter COOKIE-WAIT AFTER 4984 * sending the INIT, but that doesn't actually work in our 4985 * implementation... 4986 */ 4987 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4988 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4989 4990 /* RFC 2960 5.1 Normal Establishment of an Association 4991 * 4992 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4993 * must provide its Verification Tag (Tag_A) in the Initiate 4994 * Tag field. Tag_A SHOULD be a random number in the range of 4995 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4996 */ 4997 4998 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4999 if (!repl) 5000 goto nomem; 5001 5002 /* Choose transport for INIT. */ 5003 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5004 SCTP_CHUNK(repl)); 5005 5006 /* Cast away the const modifier, as we want to just 5007 * rerun it through as a sideffect. 5008 */ 5009 my_asoc = (struct sctp_association *)asoc; 5010 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 5011 5012 /* After sending the INIT, "A" starts the T1-init timer and 5013 * enters the COOKIE-WAIT state. 5014 */ 5015 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5016 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5018 return SCTP_DISPOSITION_CONSUME; 5019 5020 nomem: 5021 return SCTP_DISPOSITION_NOMEM; 5022 } 5023 5024 /* 5025 * Process the SEND primitive. 5026 * 5027 * Section: 10.1 ULP-to-SCTP 5028 * E) Send 5029 * 5030 * Format: SEND(association id, buffer address, byte count [,context] 5031 * [,stream id] [,life time] [,destination transport address] 5032 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 5033 * -> result 5034 * 5035 * This is the main method to send user data via SCTP. 5036 * 5037 * Mandatory attributes: 5038 * 5039 * o association id - local handle to the SCTP association 5040 * 5041 * o buffer address - the location where the user message to be 5042 * transmitted is stored; 5043 * 5044 * o byte count - The size of the user data in number of bytes; 5045 * 5046 * Optional attributes: 5047 * 5048 * o context - an optional 32 bit integer that will be carried in the 5049 * sending failure notification to the ULP if the transportation of 5050 * this User Message fails. 5051 * 5052 * o stream id - to indicate which stream to send the data on. If not 5053 * specified, stream 0 will be used. 5054 * 5055 * o life time - specifies the life time of the user data. The user data 5056 * will not be sent by SCTP after the life time expires. This 5057 * parameter can be used to avoid efforts to transmit stale 5058 * user messages. SCTP notifies the ULP if the data cannot be 5059 * initiated to transport (i.e. sent to the destination via SCTP's 5060 * send primitive) within the life time variable. However, the 5061 * user data will be transmitted if SCTP has attempted to transmit a 5062 * chunk before the life time expired. 5063 * 5064 * o destination transport address - specified as one of the destination 5065 * transport addresses of the peer endpoint to which this packet 5066 * should be sent. Whenever possible, SCTP should use this destination 5067 * transport address for sending the packets, instead of the current 5068 * primary path. 5069 * 5070 * o unorder flag - this flag, if present, indicates that the user 5071 * would like the data delivered in an unordered fashion to the peer 5072 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 5073 * message). 5074 * 5075 * o no-bundle flag - instructs SCTP not to bundle this user data with 5076 * other outbound DATA chunks. SCTP MAY still bundle even when 5077 * this flag is present, when faced with network congestion. 5078 * 5079 * o payload protocol-id - A 32 bit unsigned integer that is to be 5080 * passed to the peer indicating the type of payload protocol data 5081 * being transmitted. This value is passed as opaque data by SCTP. 5082 * 5083 * The return value is the disposition. 5084 */ 5085 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5086 const struct sctp_endpoint *ep, 5087 const struct sctp_association *asoc, 5088 const union sctp_subtype type, 5089 void *arg, 5090 struct sctp_cmd_seq *commands) 5091 { 5092 struct sctp_datamsg *msg = arg; 5093 5094 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5095 return SCTP_DISPOSITION_CONSUME; 5096 } 5097 5098 /* 5099 * Process the SHUTDOWN primitive. 5100 * 5101 * Section: 10.1: 5102 * C) Shutdown 5103 * 5104 * Format: SHUTDOWN(association id) 5105 * -> result 5106 * 5107 * Gracefully closes an association. Any locally queued user data 5108 * will be delivered to the peer. The association will be terminated only 5109 * after the peer acknowledges all the SCTP packets sent. A success code 5110 * will be returned on successful termination of the association. If 5111 * attempting to terminate the association results in a failure, an error 5112 * code shall be returned. 5113 * 5114 * Mandatory attributes: 5115 * 5116 * o association id - local handle to the SCTP association 5117 * 5118 * Optional attributes: 5119 * 5120 * None. 5121 * 5122 * The return value is the disposition. 5123 */ 5124 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5125 struct net *net, 5126 const struct sctp_endpoint *ep, 5127 const struct sctp_association *asoc, 5128 const union sctp_subtype type, 5129 void *arg, 5130 struct sctp_cmd_seq *commands) 5131 { 5132 enum sctp_disposition disposition; 5133 5134 /* From 9.2 Shutdown of an Association 5135 * Upon receipt of the SHUTDOWN primitive from its upper 5136 * layer, the endpoint enters SHUTDOWN-PENDING state and 5137 * remains there until all outstanding data has been 5138 * acknowledged by its peer. The endpoint accepts no new data 5139 * from its upper layer, but retransmits data to the far end 5140 * if necessary to fill gaps. 5141 */ 5142 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5143 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5144 5145 disposition = SCTP_DISPOSITION_CONSUME; 5146 if (sctp_outq_is_empty(&asoc->outqueue)) { 5147 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5148 arg, commands); 5149 } 5150 5151 return disposition; 5152 } 5153 5154 /* 5155 * Process the ABORT primitive. 5156 * 5157 * Section: 10.1: 5158 * C) Abort 5159 * 5160 * Format: Abort(association id [, cause code]) 5161 * -> result 5162 * 5163 * Ungracefully closes an association. Any locally queued user data 5164 * will be discarded and an ABORT chunk is sent to the peer. A success code 5165 * will be returned on successful abortion of the association. If 5166 * attempting to abort the association results in a failure, an error 5167 * code shall be returned. 5168 * 5169 * Mandatory attributes: 5170 * 5171 * o association id - local handle to the SCTP association 5172 * 5173 * Optional attributes: 5174 * 5175 * o cause code - reason of the abort to be passed to the peer 5176 * 5177 * None. 5178 * 5179 * The return value is the disposition. 5180 */ 5181 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5182 struct net *net, 5183 const struct sctp_endpoint *ep, 5184 const struct sctp_association *asoc, 5185 const union sctp_subtype type, 5186 void *arg, 5187 struct sctp_cmd_seq *commands) 5188 { 5189 /* From 9.1 Abort of an Association 5190 * Upon receipt of the ABORT primitive from its upper 5191 * layer, the endpoint enters CLOSED state and 5192 * discard all outstanding data has been 5193 * acknowledged by its peer. The endpoint accepts no new data 5194 * from its upper layer, but retransmits data to the far end 5195 * if necessary to fill gaps. 5196 */ 5197 struct sctp_chunk *abort = arg; 5198 5199 if (abort) 5200 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5201 5202 /* Even if we can't send the ABORT due to low memory delete the 5203 * TCB. This is a departure from our typical NOMEM handling. 5204 */ 5205 5206 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5207 SCTP_ERROR(ECONNABORTED)); 5208 /* Delete the established association. */ 5209 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5210 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5211 5212 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5213 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5214 5215 return SCTP_DISPOSITION_ABORT; 5216 } 5217 5218 /* We tried an illegal operation on an association which is closed. */ 5219 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5220 const struct sctp_endpoint *ep, 5221 const struct sctp_association *asoc, 5222 const union sctp_subtype type, 5223 void *arg, 5224 struct sctp_cmd_seq *commands) 5225 { 5226 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5227 return SCTP_DISPOSITION_CONSUME; 5228 } 5229 5230 /* We tried an illegal operation on an association which is shutting 5231 * down. 5232 */ 5233 enum sctp_disposition sctp_sf_error_shutdown( 5234 struct net *net, 5235 const struct sctp_endpoint *ep, 5236 const struct sctp_association *asoc, 5237 const union sctp_subtype type, 5238 void *arg, 5239 struct sctp_cmd_seq *commands) 5240 { 5241 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5242 SCTP_ERROR(-ESHUTDOWN)); 5243 return SCTP_DISPOSITION_CONSUME; 5244 } 5245 5246 /* 5247 * sctp_cookie_wait_prm_shutdown 5248 * 5249 * Section: 4 Note: 2 5250 * Verification Tag: 5251 * Inputs 5252 * (endpoint, asoc) 5253 * 5254 * The RFC does not explicitly address this issue, but is the route through the 5255 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5256 * 5257 * Outputs 5258 * (timers) 5259 */ 5260 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5261 struct net *net, 5262 const struct sctp_endpoint *ep, 5263 const struct sctp_association *asoc, 5264 const union sctp_subtype type, 5265 void *arg, 5266 struct sctp_cmd_seq *commands) 5267 { 5268 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5269 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5270 5271 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5272 SCTP_STATE(SCTP_STATE_CLOSED)); 5273 5274 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5275 5276 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5277 5278 return SCTP_DISPOSITION_DELETE_TCB; 5279 } 5280 5281 /* 5282 * sctp_cookie_echoed_prm_shutdown 5283 * 5284 * Section: 4 Note: 2 5285 * Verification Tag: 5286 * Inputs 5287 * (endpoint, asoc) 5288 * 5289 * The RFC does not explicitly address this issue, but is the route through the 5290 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5291 * 5292 * Outputs 5293 * (timers) 5294 */ 5295 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5296 struct net *net, 5297 const struct sctp_endpoint *ep, 5298 const struct sctp_association *asoc, 5299 const union sctp_subtype type, 5300 void *arg, 5301 struct sctp_cmd_seq *commands) 5302 { 5303 /* There is a single T1 timer, so we should be able to use 5304 * common function with the COOKIE-WAIT state. 5305 */ 5306 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5307 } 5308 5309 /* 5310 * sctp_sf_cookie_wait_prm_abort 5311 * 5312 * Section: 4 Note: 2 5313 * Verification Tag: 5314 * Inputs 5315 * (endpoint, asoc) 5316 * 5317 * The RFC does not explicitly address this issue, but is the route through the 5318 * state table when someone issues an abort while in COOKIE_WAIT state. 5319 * 5320 * Outputs 5321 * (timers) 5322 */ 5323 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5324 struct net *net, 5325 const struct sctp_endpoint *ep, 5326 const struct sctp_association *asoc, 5327 const union sctp_subtype type, 5328 void *arg, 5329 struct sctp_cmd_seq *commands) 5330 { 5331 struct sctp_chunk *abort = arg; 5332 5333 /* Stop T1-init timer */ 5334 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5335 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5336 5337 if (abort) 5338 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5339 5340 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5341 SCTP_STATE(SCTP_STATE_CLOSED)); 5342 5343 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5344 5345 /* Even if we can't send the ABORT due to low memory delete the 5346 * TCB. This is a departure from our typical NOMEM handling. 5347 */ 5348 5349 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5350 SCTP_ERROR(ECONNREFUSED)); 5351 /* Delete the established association. */ 5352 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5353 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5354 5355 return SCTP_DISPOSITION_ABORT; 5356 } 5357 5358 /* 5359 * sctp_sf_cookie_echoed_prm_abort 5360 * 5361 * Section: 4 Note: 3 5362 * Verification Tag: 5363 * Inputs 5364 * (endpoint, asoc) 5365 * 5366 * The RFC does not explcitly address this issue, but is the route through the 5367 * state table when someone issues an abort while in COOKIE_ECHOED state. 5368 * 5369 * Outputs 5370 * (timers) 5371 */ 5372 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5373 struct net *net, 5374 const struct sctp_endpoint *ep, 5375 const struct sctp_association *asoc, 5376 const union sctp_subtype type, 5377 void *arg, 5378 struct sctp_cmd_seq *commands) 5379 { 5380 /* There is a single T1 timer, so we should be able to use 5381 * common function with the COOKIE-WAIT state. 5382 */ 5383 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5384 } 5385 5386 /* 5387 * sctp_sf_shutdown_pending_prm_abort 5388 * 5389 * Inputs 5390 * (endpoint, asoc) 5391 * 5392 * The RFC does not explicitly address this issue, but is the route through the 5393 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5394 * 5395 * Outputs 5396 * (timers) 5397 */ 5398 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5399 struct net *net, 5400 const struct sctp_endpoint *ep, 5401 const struct sctp_association *asoc, 5402 const union sctp_subtype type, 5403 void *arg, 5404 struct sctp_cmd_seq *commands) 5405 { 5406 /* Stop the T5-shutdown guard timer. */ 5407 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5408 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5409 5410 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5411 } 5412 5413 /* 5414 * sctp_sf_shutdown_sent_prm_abort 5415 * 5416 * Inputs 5417 * (endpoint, asoc) 5418 * 5419 * The RFC does not explicitly address this issue, but is the route through the 5420 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5421 * 5422 * Outputs 5423 * (timers) 5424 */ 5425 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5426 struct net *net, 5427 const struct sctp_endpoint *ep, 5428 const struct sctp_association *asoc, 5429 const union sctp_subtype type, 5430 void *arg, 5431 struct sctp_cmd_seq *commands) 5432 { 5433 /* Stop the T2-shutdown timer. */ 5434 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5435 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5436 5437 /* Stop the T5-shutdown guard timer. */ 5438 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5439 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5440 5441 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5442 } 5443 5444 /* 5445 * sctp_sf_cookie_echoed_prm_abort 5446 * 5447 * Inputs 5448 * (endpoint, asoc) 5449 * 5450 * The RFC does not explcitly address this issue, but is the route through the 5451 * state table when someone issues an abort while in COOKIE_ECHOED state. 5452 * 5453 * Outputs 5454 * (timers) 5455 */ 5456 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5457 struct net *net, 5458 const struct sctp_endpoint *ep, 5459 const struct sctp_association *asoc, 5460 const union sctp_subtype type, 5461 void *arg, 5462 struct sctp_cmd_seq *commands) 5463 { 5464 /* The same T2 timer, so we should be able to use 5465 * common function with the SHUTDOWN-SENT state. 5466 */ 5467 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5468 } 5469 5470 /* 5471 * Process the REQUESTHEARTBEAT primitive 5472 * 5473 * 10.1 ULP-to-SCTP 5474 * J) Request Heartbeat 5475 * 5476 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5477 * 5478 * -> result 5479 * 5480 * Instructs the local endpoint to perform a HeartBeat on the specified 5481 * destination transport address of the given association. The returned 5482 * result should indicate whether the transmission of the HEARTBEAT 5483 * chunk to the destination address is successful. 5484 * 5485 * Mandatory attributes: 5486 * 5487 * o association id - local handle to the SCTP association 5488 * 5489 * o destination transport address - the transport address of the 5490 * association on which a heartbeat should be issued. 5491 */ 5492 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5493 struct net *net, 5494 const struct sctp_endpoint *ep, 5495 const struct sctp_association *asoc, 5496 const union sctp_subtype type, 5497 void *arg, 5498 struct sctp_cmd_seq *commands) 5499 { 5500 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5501 (struct sctp_transport *)arg, commands)) 5502 return SCTP_DISPOSITION_NOMEM; 5503 5504 /* 5505 * RFC 2960 (bis), section 8.3 5506 * 5507 * D) Request an on-demand HEARTBEAT on a specific destination 5508 * transport address of a given association. 5509 * 5510 * The endpoint should increment the respective error counter of 5511 * the destination transport address each time a HEARTBEAT is sent 5512 * to that address and not acknowledged within one RTO. 5513 * 5514 */ 5515 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5516 SCTP_TRANSPORT(arg)); 5517 return SCTP_DISPOSITION_CONSUME; 5518 } 5519 5520 /* 5521 * ADDIP Section 4.1 ASCONF Chunk Procedures 5522 * When an endpoint has an ASCONF signaled change to be sent to the 5523 * remote endpoint it should do A1 to A9 5524 */ 5525 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5526 const struct sctp_endpoint *ep, 5527 const struct sctp_association *asoc, 5528 const union sctp_subtype type, 5529 void *arg, 5530 struct sctp_cmd_seq *commands) 5531 { 5532 struct sctp_chunk *chunk = arg; 5533 5534 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5535 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5536 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5537 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5538 return SCTP_DISPOSITION_CONSUME; 5539 } 5540 5541 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5542 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5543 const struct sctp_endpoint *ep, 5544 const struct sctp_association *asoc, 5545 const union sctp_subtype type, 5546 void *arg, 5547 struct sctp_cmd_seq *commands) 5548 { 5549 struct sctp_chunk *chunk = arg; 5550 5551 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5552 return SCTP_DISPOSITION_CONSUME; 5553 } 5554 5555 /* 5556 * Ignore the primitive event 5557 * 5558 * The return value is the disposition of the primitive. 5559 */ 5560 enum sctp_disposition sctp_sf_ignore_primitive( 5561 struct net *net, 5562 const struct sctp_endpoint *ep, 5563 const struct sctp_association *asoc, 5564 const union sctp_subtype type, 5565 void *arg, 5566 struct sctp_cmd_seq *commands) 5567 { 5568 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5569 type.primitive); 5570 5571 return SCTP_DISPOSITION_DISCARD; 5572 } 5573 5574 /*************************************************************************** 5575 * These are the state functions for the OTHER events. 5576 ***************************************************************************/ 5577 5578 /* 5579 * When the SCTP stack has no more user data to send or retransmit, this 5580 * notification is given to the user. Also, at the time when a user app 5581 * subscribes to this event, if there is no data to be sent or 5582 * retransmit, the stack will immediately send up this notification. 5583 */ 5584 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5585 struct net *net, 5586 const struct sctp_endpoint *ep, 5587 const struct sctp_association *asoc, 5588 const union sctp_subtype type, 5589 void *arg, 5590 struct sctp_cmd_seq *commands) 5591 { 5592 struct sctp_ulpevent *event; 5593 5594 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5595 if (!event) 5596 return SCTP_DISPOSITION_NOMEM; 5597 5598 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5599 5600 return SCTP_DISPOSITION_CONSUME; 5601 } 5602 5603 /* 5604 * Start the shutdown negotiation. 5605 * 5606 * From Section 9.2: 5607 * Once all its outstanding data has been acknowledged, the endpoint 5608 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5609 * TSN Ack field the last sequential TSN it has received from the peer. 5610 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5611 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5612 * with the updated last sequential TSN received from its peer. 5613 * 5614 * The return value is the disposition. 5615 */ 5616 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5617 struct net *net, 5618 const struct sctp_endpoint *ep, 5619 const struct sctp_association *asoc, 5620 const union sctp_subtype type, 5621 void *arg, 5622 struct sctp_cmd_seq *commands) 5623 { 5624 struct sctp_chunk *reply; 5625 5626 /* Once all its outstanding data has been acknowledged, the 5627 * endpoint shall send a SHUTDOWN chunk to its peer including 5628 * in the Cumulative TSN Ack field the last sequential TSN it 5629 * has received from the peer. 5630 */ 5631 reply = sctp_make_shutdown(asoc, arg); 5632 if (!reply) 5633 goto nomem; 5634 5635 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5636 * T2-shutdown timer. 5637 */ 5638 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5639 5640 /* It shall then start the T2-shutdown timer */ 5641 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5642 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5643 5644 /* RFC 4960 Section 9.2 5645 * The sender of the SHUTDOWN MAY also start an overall guard timer 5646 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5647 */ 5648 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5649 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5650 5651 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5652 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5653 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5654 5655 /* and enter the SHUTDOWN-SENT state. */ 5656 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5657 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5658 5659 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5660 * 5661 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5662 * or SHUTDOWN-ACK. 5663 */ 5664 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5665 5666 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5667 5668 return SCTP_DISPOSITION_CONSUME; 5669 5670 nomem: 5671 return SCTP_DISPOSITION_NOMEM; 5672 } 5673 5674 /* 5675 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5676 * 5677 * From Section 9.2: 5678 * 5679 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5680 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5681 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5682 * endpoint must re-send the SHUTDOWN ACK. 5683 * 5684 * The return value is the disposition. 5685 */ 5686 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5687 struct net *net, 5688 const struct sctp_endpoint *ep, 5689 const struct sctp_association *asoc, 5690 const union sctp_subtype type, 5691 void *arg, 5692 struct sctp_cmd_seq *commands) 5693 { 5694 struct sctp_chunk *chunk = arg; 5695 struct sctp_chunk *reply; 5696 5697 /* There are 2 ways of getting here: 5698 * 1) called in response to a SHUTDOWN chunk 5699 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5700 * 5701 * For the case (2), the arg parameter is set to NULL. We need 5702 * to check that we have a chunk before accessing it's fields. 5703 */ 5704 if (chunk) { 5705 if (!sctp_vtag_verify(chunk, asoc)) 5706 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5707 commands); 5708 5709 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5710 if (!sctp_chunk_length_valid( 5711 chunk, sizeof(struct sctp_shutdown_chunk))) 5712 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5713 arg, commands); 5714 } 5715 5716 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5717 * shall send a SHUTDOWN ACK ... 5718 */ 5719 reply = sctp_make_shutdown_ack(asoc, chunk); 5720 if (!reply) 5721 goto nomem; 5722 5723 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5724 * the T2-shutdown timer. 5725 */ 5726 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5727 5728 /* and start/restart a T2-shutdown timer of its own, */ 5729 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5730 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5731 5732 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5733 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5734 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5735 5736 /* Enter the SHUTDOWN-ACK-SENT state. */ 5737 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5738 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5739 5740 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5741 * 5742 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5743 * or SHUTDOWN-ACK. 5744 */ 5745 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5746 5747 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5748 5749 return SCTP_DISPOSITION_CONSUME; 5750 5751 nomem: 5752 return SCTP_DISPOSITION_NOMEM; 5753 } 5754 5755 /* 5756 * Ignore the event defined as other 5757 * 5758 * The return value is the disposition of the event. 5759 */ 5760 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5761 const struct sctp_endpoint *ep, 5762 const struct sctp_association *asoc, 5763 const union sctp_subtype type, 5764 void *arg, 5765 struct sctp_cmd_seq *commands) 5766 { 5767 pr_debug("%s: the event other type:%d is ignored\n", 5768 __func__, type.other); 5769 5770 return SCTP_DISPOSITION_DISCARD; 5771 } 5772 5773 /************************************************************ 5774 * These are the state functions for handling timeout events. 5775 ************************************************************/ 5776 5777 /* 5778 * RTX Timeout 5779 * 5780 * Section: 6.3.3 Handle T3-rtx Expiration 5781 * 5782 * Whenever the retransmission timer T3-rtx expires for a destination 5783 * address, do the following: 5784 * [See below] 5785 * 5786 * The return value is the disposition of the chunk. 5787 */ 5788 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5789 const struct sctp_endpoint *ep, 5790 const struct sctp_association *asoc, 5791 const union sctp_subtype type, 5792 void *arg, 5793 struct sctp_cmd_seq *commands) 5794 { 5795 struct sctp_transport *transport = arg; 5796 5797 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5798 5799 if (asoc->overall_error_count >= asoc->max_retrans) { 5800 if (asoc->peer.zero_window_announced && 5801 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5802 /* 5803 * We are here likely because the receiver had its rwnd 5804 * closed for a while and we have not been able to 5805 * transmit the locally queued data within the maximum 5806 * retransmission attempts limit. Start the T5 5807 * shutdown guard timer to give the receiver one last 5808 * chance and some additional time to recover before 5809 * aborting. 5810 */ 5811 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5812 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5813 } else { 5814 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5815 SCTP_ERROR(ETIMEDOUT)); 5816 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5817 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5818 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5819 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5820 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5821 return SCTP_DISPOSITION_DELETE_TCB; 5822 } 5823 } 5824 5825 /* E1) For the destination address for which the timer 5826 * expires, adjust its ssthresh with rules defined in Section 5827 * 7.2.3 and set the cwnd <- MTU. 5828 */ 5829 5830 /* E2) For the destination address for which the timer 5831 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5832 * maximum value discussed in rule C7 above (RTO.max) may be 5833 * used to provide an upper bound to this doubling operation. 5834 */ 5835 5836 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5837 * outstanding DATA chunks for the address for which the 5838 * T3-rtx has expired will fit into a single packet, subject 5839 * to the MTU constraint for the path corresponding to the 5840 * destination transport address to which the retransmission 5841 * is being sent (this may be different from the address for 5842 * which the timer expires [see Section 6.4]). Call this 5843 * value K. Bundle and retransmit those K DATA chunks in a 5844 * single packet to the destination endpoint. 5845 * 5846 * Note: Any DATA chunks that were sent to the address for 5847 * which the T3-rtx timer expired but did not fit in one MTU 5848 * (rule E3 above), should be marked for retransmission and 5849 * sent as soon as cwnd allows (normally when a SACK arrives). 5850 */ 5851 5852 /* Do some failure management (Section 8.2). */ 5853 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5854 5855 /* NB: Rules E4 and F1 are implicit in R1. */ 5856 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5857 5858 return SCTP_DISPOSITION_CONSUME; 5859 } 5860 5861 /* 5862 * Generate delayed SACK on timeout 5863 * 5864 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5865 * 5866 * The guidelines on delayed acknowledgement algorithm specified in 5867 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5868 * acknowledgement SHOULD be generated for at least every second packet 5869 * (not every second DATA chunk) received, and SHOULD be generated 5870 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5871 * some situations it may be beneficial for an SCTP transmitter to be 5872 * more conservative than the algorithms detailed in this document 5873 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5874 * the following algorithms allow. 5875 */ 5876 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5877 const struct sctp_endpoint *ep, 5878 const struct sctp_association *asoc, 5879 const union sctp_subtype type, 5880 void *arg, 5881 struct sctp_cmd_seq *commands) 5882 { 5883 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5884 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5885 return SCTP_DISPOSITION_CONSUME; 5886 } 5887 5888 /* 5889 * sctp_sf_t1_init_timer_expire 5890 * 5891 * Section: 4 Note: 2 5892 * Verification Tag: 5893 * Inputs 5894 * (endpoint, asoc) 5895 * 5896 * RFC 2960 Section 4 Notes 5897 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5898 * and re-start the T1-init timer without changing state. This MUST 5899 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5900 * endpoint MUST abort the initialization process and report the 5901 * error to SCTP user. 5902 * 5903 * Outputs 5904 * (timers, events) 5905 * 5906 */ 5907 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5908 struct net *net, 5909 const struct sctp_endpoint *ep, 5910 const struct sctp_association *asoc, 5911 const union sctp_subtype type, 5912 void *arg, 5913 struct sctp_cmd_seq *commands) 5914 { 5915 int attempts = asoc->init_err_counter + 1; 5916 struct sctp_chunk *repl = NULL; 5917 struct sctp_bind_addr *bp; 5918 5919 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5920 5921 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5922 5923 if (attempts <= asoc->max_init_attempts) { 5924 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5925 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5926 if (!repl) 5927 return SCTP_DISPOSITION_NOMEM; 5928 5929 /* Choose transport for INIT. */ 5930 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5931 SCTP_CHUNK(repl)); 5932 5933 /* Issue a sideeffect to do the needed accounting. */ 5934 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5935 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5936 5937 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5938 } else { 5939 pr_debug("%s: giving up on INIT, attempts:%d " 5940 "max_init_attempts:%d\n", __func__, attempts, 5941 asoc->max_init_attempts); 5942 5943 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5944 SCTP_ERROR(ETIMEDOUT)); 5945 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5946 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5947 return SCTP_DISPOSITION_DELETE_TCB; 5948 } 5949 5950 return SCTP_DISPOSITION_CONSUME; 5951 } 5952 5953 /* 5954 * sctp_sf_t1_cookie_timer_expire 5955 * 5956 * Section: 4 Note: 2 5957 * Verification Tag: 5958 * Inputs 5959 * (endpoint, asoc) 5960 * 5961 * RFC 2960 Section 4 Notes 5962 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5963 * COOKIE ECHO and re-start the T1-cookie timer without changing 5964 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5965 * After that, the endpoint MUST abort the initialization process and 5966 * report the error to SCTP user. 5967 * 5968 * Outputs 5969 * (timers, events) 5970 * 5971 */ 5972 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5973 struct net *net, 5974 const struct sctp_endpoint *ep, 5975 const struct sctp_association *asoc, 5976 const union sctp_subtype type, 5977 void *arg, 5978 struct sctp_cmd_seq *commands) 5979 { 5980 int attempts = asoc->init_err_counter + 1; 5981 struct sctp_chunk *repl = NULL; 5982 5983 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5984 5985 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5986 5987 if (attempts <= asoc->max_init_attempts) { 5988 repl = sctp_make_cookie_echo(asoc, NULL); 5989 if (!repl) 5990 return SCTP_DISPOSITION_NOMEM; 5991 5992 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5993 SCTP_CHUNK(repl)); 5994 /* Issue a sideeffect to do the needed accounting. */ 5995 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5996 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5997 5998 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5999 } else { 6000 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6001 SCTP_ERROR(ETIMEDOUT)); 6002 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 6003 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6004 return SCTP_DISPOSITION_DELETE_TCB; 6005 } 6006 6007 return SCTP_DISPOSITION_CONSUME; 6008 } 6009 6010 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 6011 * with the updated last sequential TSN received from its peer. 6012 * 6013 * An endpoint should limit the number of retransmission of the 6014 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 6015 * If this threshold is exceeded the endpoint should destroy the TCB and 6016 * MUST report the peer endpoint unreachable to the upper layer (and 6017 * thus the association enters the CLOSED state). The reception of any 6018 * packet from its peer (i.e. as the peer sends all of its queued DATA 6019 * chunks) should clear the endpoint's retransmission count and restart 6020 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 6021 * all of its queued DATA chunks that have not yet been sent. 6022 */ 6023 enum sctp_disposition sctp_sf_t2_timer_expire( 6024 struct net *net, 6025 const struct sctp_endpoint *ep, 6026 const struct sctp_association *asoc, 6027 const union sctp_subtype type, 6028 void *arg, 6029 struct sctp_cmd_seq *commands) 6030 { 6031 struct sctp_chunk *reply = NULL; 6032 6033 pr_debug("%s: timer T2 expired\n", __func__); 6034 6035 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 6036 6037 ((struct sctp_association *)asoc)->shutdown_retries++; 6038 6039 if (asoc->overall_error_count >= asoc->max_retrans) { 6040 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6041 SCTP_ERROR(ETIMEDOUT)); 6042 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 6043 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6044 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6045 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6046 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6047 return SCTP_DISPOSITION_DELETE_TCB; 6048 } 6049 6050 switch (asoc->state) { 6051 case SCTP_STATE_SHUTDOWN_SENT: 6052 reply = sctp_make_shutdown(asoc, NULL); 6053 break; 6054 6055 case SCTP_STATE_SHUTDOWN_ACK_SENT: 6056 reply = sctp_make_shutdown_ack(asoc, NULL); 6057 break; 6058 6059 default: 6060 BUG(); 6061 break; 6062 } 6063 6064 if (!reply) 6065 goto nomem; 6066 6067 /* Do some failure management (Section 8.2). 6068 * If we remove the transport an SHUTDOWN was last sent to, don't 6069 * do failure management. 6070 */ 6071 if (asoc->shutdown_last_sent_to) 6072 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6073 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 6074 6075 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 6076 * the T2-shutdown timer. 6077 */ 6078 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6079 6080 /* Restart the T2-shutdown timer. */ 6081 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6082 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6083 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6084 return SCTP_DISPOSITION_CONSUME; 6085 6086 nomem: 6087 return SCTP_DISPOSITION_NOMEM; 6088 } 6089 6090 /* 6091 * ADDIP Section 4.1 ASCONF Chunk Procedures 6092 * If the T4 RTO timer expires the endpoint should do B1 to B5 6093 */ 6094 enum sctp_disposition sctp_sf_t4_timer_expire( 6095 struct net *net, 6096 const struct sctp_endpoint *ep, 6097 const struct sctp_association *asoc, 6098 const union sctp_subtype type, 6099 void *arg, 6100 struct sctp_cmd_seq *commands) 6101 { 6102 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6103 struct sctp_transport *transport = chunk->transport; 6104 6105 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6106 6107 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6108 * detection on the appropriate destination address as defined in 6109 * RFC2960 [5] section 8.1 and 8.2. 6110 */ 6111 if (transport) 6112 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6113 SCTP_TRANSPORT(transport)); 6114 6115 /* Reconfig T4 timer and transport. */ 6116 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6117 6118 /* ADDIP 4.1 B2) Increment the association error counters and perform 6119 * endpoint failure detection on the association as defined in 6120 * RFC2960 [5] section 8.1 and 8.2. 6121 * association error counter is incremented in SCTP_CMD_STRIKE. 6122 */ 6123 if (asoc->overall_error_count >= asoc->max_retrans) { 6124 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6125 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6126 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6127 SCTP_ERROR(ETIMEDOUT)); 6128 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6129 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6130 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6131 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6132 return SCTP_DISPOSITION_ABORT; 6133 } 6134 6135 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6136 * the ASCONF chunk was sent by doubling the RTO timer value. 6137 * This is done in SCTP_CMD_STRIKE. 6138 */ 6139 6140 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6141 * choose an alternate destination address (please refer to RFC2960 6142 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6143 * chunk, it MUST be the same (including its serial number) as the last 6144 * ASCONF sent. 6145 */ 6146 sctp_chunk_hold(asoc->addip_last_asconf); 6147 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6148 SCTP_CHUNK(asoc->addip_last_asconf)); 6149 6150 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6151 * destination is selected, then the RTO used will be that of the new 6152 * destination address. 6153 */ 6154 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6155 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6156 6157 return SCTP_DISPOSITION_CONSUME; 6158 } 6159 6160 /* sctpimpguide-05 Section 2.12.2 6161 * The sender of the SHUTDOWN MAY also start an overall guard timer 6162 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6163 * At the expiration of this timer the sender SHOULD abort the association 6164 * by sending an ABORT chunk. 6165 */ 6166 enum sctp_disposition sctp_sf_t5_timer_expire( 6167 struct net *net, 6168 const struct sctp_endpoint *ep, 6169 const struct sctp_association *asoc, 6170 const union sctp_subtype type, 6171 void *arg, 6172 struct sctp_cmd_seq *commands) 6173 { 6174 struct sctp_chunk *reply = NULL; 6175 6176 pr_debug("%s: timer T5 expired\n", __func__); 6177 6178 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6179 6180 reply = sctp_make_abort(asoc, NULL, 0); 6181 if (!reply) 6182 goto nomem; 6183 6184 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6185 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6186 SCTP_ERROR(ETIMEDOUT)); 6187 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6188 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6189 6190 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6191 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6192 6193 return SCTP_DISPOSITION_DELETE_TCB; 6194 nomem: 6195 return SCTP_DISPOSITION_NOMEM; 6196 } 6197 6198 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6199 * the association is automatically closed by starting the shutdown process. 6200 * The work that needs to be done is same as when SHUTDOWN is initiated by 6201 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6202 */ 6203 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6204 struct net *net, 6205 const struct sctp_endpoint *ep, 6206 const struct sctp_association *asoc, 6207 const union sctp_subtype type, 6208 void *arg, 6209 struct sctp_cmd_seq *commands) 6210 { 6211 enum sctp_disposition disposition; 6212 6213 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6214 6215 /* From 9.2 Shutdown of an Association 6216 * Upon receipt of the SHUTDOWN primitive from its upper 6217 * layer, the endpoint enters SHUTDOWN-PENDING state and 6218 * remains there until all outstanding data has been 6219 * acknowledged by its peer. The endpoint accepts no new data 6220 * from its upper layer, but retransmits data to the far end 6221 * if necessary to fill gaps. 6222 */ 6223 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6224 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6225 6226 disposition = SCTP_DISPOSITION_CONSUME; 6227 if (sctp_outq_is_empty(&asoc->outqueue)) { 6228 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6229 NULL, commands); 6230 } 6231 6232 return disposition; 6233 } 6234 6235 /***************************************************************************** 6236 * These are sa state functions which could apply to all types of events. 6237 ****************************************************************************/ 6238 6239 /* 6240 * This table entry is not implemented. 6241 * 6242 * Inputs 6243 * (endpoint, asoc, chunk) 6244 * 6245 * The return value is the disposition of the chunk. 6246 */ 6247 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6248 const struct sctp_endpoint *ep, 6249 const struct sctp_association *asoc, 6250 const union sctp_subtype type, 6251 void *arg, struct sctp_cmd_seq *commands) 6252 { 6253 return SCTP_DISPOSITION_NOT_IMPL; 6254 } 6255 6256 /* 6257 * This table entry represents a bug. 6258 * 6259 * Inputs 6260 * (endpoint, asoc, chunk) 6261 * 6262 * The return value is the disposition of the chunk. 6263 */ 6264 enum sctp_disposition sctp_sf_bug(struct net *net, 6265 const struct sctp_endpoint *ep, 6266 const struct sctp_association *asoc, 6267 const union sctp_subtype type, 6268 void *arg, struct sctp_cmd_seq *commands) 6269 { 6270 return SCTP_DISPOSITION_BUG; 6271 } 6272 6273 /* 6274 * This table entry represents the firing of a timer in the wrong state. 6275 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6276 * when the association is in the wrong state. This event should 6277 * be ignored, so as to prevent any rearming of the timer. 6278 * 6279 * Inputs 6280 * (endpoint, asoc, chunk) 6281 * 6282 * The return value is the disposition of the chunk. 6283 */ 6284 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6285 const struct sctp_endpoint *ep, 6286 const struct sctp_association *asoc, 6287 const union sctp_subtype type, 6288 void *arg, 6289 struct sctp_cmd_seq *commands) 6290 { 6291 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6292 6293 return SCTP_DISPOSITION_CONSUME; 6294 } 6295 6296 /******************************************************************** 6297 * 2nd Level Abstractions 6298 ********************************************************************/ 6299 6300 /* Pull the SACK chunk based on the SACK header. */ 6301 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6302 { 6303 struct sctp_sackhdr *sack; 6304 __u16 num_dup_tsns; 6305 unsigned int len; 6306 __u16 num_blocks; 6307 6308 /* Protect ourselves from reading too far into 6309 * the skb from a bogus sender. 6310 */ 6311 sack = (struct sctp_sackhdr *) chunk->skb->data; 6312 6313 num_blocks = ntohs(sack->num_gap_ack_blocks); 6314 num_dup_tsns = ntohs(sack->num_dup_tsns); 6315 len = sizeof(struct sctp_sackhdr); 6316 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6317 if (len > chunk->skb->len) 6318 return NULL; 6319 6320 skb_pull(chunk->skb, len); 6321 6322 return sack; 6323 } 6324 6325 /* Create an ABORT packet to be sent as a response, with the specified 6326 * error causes. 6327 */ 6328 static struct sctp_packet *sctp_abort_pkt_new( 6329 struct net *net, 6330 const struct sctp_endpoint *ep, 6331 const struct sctp_association *asoc, 6332 struct sctp_chunk *chunk, 6333 const void *payload, size_t paylen) 6334 { 6335 struct sctp_packet *packet; 6336 struct sctp_chunk *abort; 6337 6338 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6339 6340 if (packet) { 6341 /* Make an ABORT. 6342 * The T bit will be set if the asoc is NULL. 6343 */ 6344 abort = sctp_make_abort(asoc, chunk, paylen); 6345 if (!abort) { 6346 sctp_ootb_pkt_free(packet); 6347 return NULL; 6348 } 6349 6350 /* Reflect vtag if T-Bit is set */ 6351 if (sctp_test_T_bit(abort)) 6352 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6353 6354 /* Add specified error causes, i.e., payload, to the 6355 * end of the chunk. 6356 */ 6357 sctp_addto_chunk(abort, paylen, payload); 6358 6359 /* Set the skb to the belonging sock for accounting. */ 6360 abort->skb->sk = ep->base.sk; 6361 6362 sctp_packet_append_chunk(packet, abort); 6363 6364 } 6365 6366 return packet; 6367 } 6368 6369 /* Allocate a packet for responding in the OOTB conditions. */ 6370 static struct sctp_packet *sctp_ootb_pkt_new( 6371 struct net *net, 6372 const struct sctp_association *asoc, 6373 const struct sctp_chunk *chunk) 6374 { 6375 struct sctp_transport *transport; 6376 struct sctp_packet *packet; 6377 __u16 sport, dport; 6378 __u32 vtag; 6379 6380 /* Get the source and destination port from the inbound packet. */ 6381 sport = ntohs(chunk->sctp_hdr->dest); 6382 dport = ntohs(chunk->sctp_hdr->source); 6383 6384 /* The V-tag is going to be the same as the inbound packet if no 6385 * association exists, otherwise, use the peer's vtag. 6386 */ 6387 if (asoc) { 6388 /* Special case the INIT-ACK as there is no peer's vtag 6389 * yet. 6390 */ 6391 switch (chunk->chunk_hdr->type) { 6392 case SCTP_CID_INIT: 6393 case SCTP_CID_INIT_ACK: 6394 { 6395 struct sctp_initack_chunk *initack; 6396 6397 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6398 vtag = ntohl(initack->init_hdr.init_tag); 6399 break; 6400 } 6401 default: 6402 vtag = asoc->peer.i.init_tag; 6403 break; 6404 } 6405 } else { 6406 /* Special case the INIT and stale COOKIE_ECHO as there is no 6407 * vtag yet. 6408 */ 6409 switch (chunk->chunk_hdr->type) { 6410 case SCTP_CID_INIT: 6411 { 6412 struct sctp_init_chunk *init; 6413 6414 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6415 vtag = ntohl(init->init_hdr.init_tag); 6416 break; 6417 } 6418 default: 6419 vtag = ntohl(chunk->sctp_hdr->vtag); 6420 break; 6421 } 6422 } 6423 6424 /* Make a transport for the bucket, Eliza... */ 6425 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6426 if (!transport) 6427 goto nomem; 6428 6429 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6430 6431 /* Cache a route for the transport with the chunk's destination as 6432 * the source address. 6433 */ 6434 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6435 sctp_sk(net->sctp.ctl_sock)); 6436 6437 packet = &transport->packet; 6438 sctp_packet_init(packet, transport, sport, dport); 6439 sctp_packet_config(packet, vtag, 0); 6440 6441 return packet; 6442 6443 nomem: 6444 return NULL; 6445 } 6446 6447 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6448 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6449 { 6450 sctp_transport_free(packet->transport); 6451 } 6452 6453 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6454 static void sctp_send_stale_cookie_err(struct net *net, 6455 const struct sctp_endpoint *ep, 6456 const struct sctp_association *asoc, 6457 const struct sctp_chunk *chunk, 6458 struct sctp_cmd_seq *commands, 6459 struct sctp_chunk *err_chunk) 6460 { 6461 struct sctp_packet *packet; 6462 6463 if (err_chunk) { 6464 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6465 if (packet) { 6466 struct sctp_signed_cookie *cookie; 6467 6468 /* Override the OOTB vtag from the cookie. */ 6469 cookie = chunk->subh.cookie_hdr; 6470 packet->vtag = cookie->c.peer_vtag; 6471 6472 /* Set the skb to the belonging sock for accounting. */ 6473 err_chunk->skb->sk = ep->base.sk; 6474 sctp_packet_append_chunk(packet, err_chunk); 6475 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6476 SCTP_PACKET(packet)); 6477 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6478 } else 6479 sctp_chunk_free (err_chunk); 6480 } 6481 } 6482 6483 6484 /* Process a data chunk */ 6485 static int sctp_eat_data(const struct sctp_association *asoc, 6486 struct sctp_chunk *chunk, 6487 struct sctp_cmd_seq *commands) 6488 { 6489 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6490 struct sock *sk = asoc->base.sk; 6491 struct net *net = sock_net(sk); 6492 struct sctp_datahdr *data_hdr; 6493 struct sctp_chunk *err; 6494 enum sctp_verb deliver; 6495 size_t datalen; 6496 __u32 tsn; 6497 int tmp; 6498 6499 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6500 chunk->subh.data_hdr = data_hdr; 6501 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6502 6503 tsn = ntohl(data_hdr->tsn); 6504 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6505 6506 /* ASSERT: Now skb->data is really the user data. */ 6507 6508 /* Process ECN based congestion. 6509 * 6510 * Since the chunk structure is reused for all chunks within 6511 * a packet, we use ecn_ce_done to track if we've already 6512 * done CE processing for this packet. 6513 * 6514 * We need to do ECN processing even if we plan to discard the 6515 * chunk later. 6516 */ 6517 6518 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6519 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6520 chunk->ecn_ce_done = 1; 6521 6522 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6523 /* Do real work as side effect. */ 6524 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6525 SCTP_U32(tsn)); 6526 } 6527 } 6528 6529 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6530 if (tmp < 0) { 6531 /* The TSN is too high--silently discard the chunk and 6532 * count on it getting retransmitted later. 6533 */ 6534 if (chunk->asoc) 6535 chunk->asoc->stats.outofseqtsns++; 6536 return SCTP_IERROR_HIGH_TSN; 6537 } else if (tmp > 0) { 6538 /* This is a duplicate. Record it. */ 6539 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6540 return SCTP_IERROR_DUP_TSN; 6541 } 6542 6543 /* This is a new TSN. */ 6544 6545 /* Discard if there is no room in the receive window. 6546 * Actually, allow a little bit of overflow (up to a MTU). 6547 */ 6548 datalen = ntohs(chunk->chunk_hdr->length); 6549 datalen -= sctp_datachk_len(&asoc->stream); 6550 6551 deliver = SCTP_CMD_CHUNK_ULP; 6552 6553 /* Think about partial delivery. */ 6554 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6555 6556 /* Even if we don't accept this chunk there is 6557 * memory pressure. 6558 */ 6559 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6560 } 6561 6562 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6563 * seems a bit troublesome in that frag_point varies based on 6564 * PMTU. In cases, such as loopback, this might be a rather 6565 * large spill over. 6566 */ 6567 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6568 (datalen > asoc->rwnd + asoc->frag_point))) { 6569 6570 /* If this is the next TSN, consider reneging to make 6571 * room. Note: Playing nice with a confused sender. A 6572 * malicious sender can still eat up all our buffer 6573 * space and in the future we may want to detect and 6574 * do more drastic reneging. 6575 */ 6576 if (sctp_tsnmap_has_gap(map) && 6577 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6578 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6579 deliver = SCTP_CMD_RENEGE; 6580 } else { 6581 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6582 __func__, tsn, datalen, asoc->rwnd); 6583 6584 return SCTP_IERROR_IGNORE_TSN; 6585 } 6586 } 6587 6588 /* 6589 * Also try to renege to limit our memory usage in the event that 6590 * we are under memory pressure 6591 * If we can't renege, don't worry about it, the sk_rmem_schedule 6592 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6593 * memory usage too much 6594 */ 6595 if (sk_under_memory_pressure(sk)) { 6596 if (sctp_tsnmap_has_gap(map) && 6597 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6598 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6599 __func__, tsn); 6600 deliver = SCTP_CMD_RENEGE; 6601 } 6602 } 6603 6604 /* 6605 * Section 3.3.10.9 No User Data (9) 6606 * 6607 * Cause of error 6608 * --------------- 6609 * No User Data: This error cause is returned to the originator of a 6610 * DATA chunk if a received DATA chunk has no user data. 6611 */ 6612 if (unlikely(0 == datalen)) { 6613 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6614 if (err) { 6615 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6616 SCTP_CHUNK(err)); 6617 } 6618 /* We are going to ABORT, so we might as well stop 6619 * processing the rest of the chunks in the packet. 6620 */ 6621 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6622 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6623 SCTP_ERROR(ECONNABORTED)); 6624 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6625 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6626 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6627 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6628 return SCTP_IERROR_NO_DATA; 6629 } 6630 6631 chunk->data_accepted = 1; 6632 6633 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6634 * if we renege and the chunk arrives again. 6635 */ 6636 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6637 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6638 if (chunk->asoc) 6639 chunk->asoc->stats.iuodchunks++; 6640 } else { 6641 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6642 if (chunk->asoc) 6643 chunk->asoc->stats.iodchunks++; 6644 } 6645 6646 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6647 * 6648 * If an endpoint receive a DATA chunk with an invalid stream 6649 * identifier, it shall acknowledge the reception of the DATA chunk 6650 * following the normal procedure, immediately send an ERROR chunk 6651 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6652 * and discard the DATA chunk. 6653 */ 6654 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6655 /* Mark tsn as received even though we drop it */ 6656 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6657 6658 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6659 &data_hdr->stream, 6660 sizeof(data_hdr->stream), 6661 sizeof(u16)); 6662 if (err) 6663 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6664 SCTP_CHUNK(err)); 6665 return SCTP_IERROR_BAD_STREAM; 6666 } 6667 6668 /* Check to see if the SSN is possible for this TSN. 6669 * The biggest gap we can record is 4K wide. Since SSNs wrap 6670 * at an unsigned short, there is no way that an SSN can 6671 * wrap and for a valid TSN. We can simply check if the current 6672 * SSN is smaller then the next expected one. If it is, it wrapped 6673 * and is invalid. 6674 */ 6675 if (!asoc->stream.si->validate_data(chunk)) 6676 return SCTP_IERROR_PROTO_VIOLATION; 6677 6678 /* Send the data up to the user. Note: Schedule the 6679 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6680 * chunk needs the updated rwnd. 6681 */ 6682 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6683 6684 return SCTP_IERROR_NO_ERROR; 6685 } 6686