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