1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999-2000 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * Copyright (c) 2001-2002 Intel Corp. 7 * Copyright (c) 2002 Nokia Corp. 8 * 9 * This is part of the SCTP Linux Kernel Implementation. 10 * 11 * These are the state functions for the state machine. 12 * 13 * Please send any bug reports or fixes you make to the 14 * email address(es): 15 * lksctp developers <linux-sctp@vger.kernel.org> 16 * 17 * Written or modified by: 18 * La Monte H.P. Yarroll <piggy@acm.org> 19 * Karl Knutson <karl@athena.chicago.il.us> 20 * Mathew Kotowsky <kotowsky@sctp.org> 21 * Sridhar Samudrala <samudrala@us.ibm.com> 22 * Jon Grimm <jgrimm@us.ibm.com> 23 * Hui Huang <hui.huang@nokia.com> 24 * Dajiang Zhang <dajiang.zhang@nokia.com> 25 * Daisy Chang <daisyc@us.ibm.com> 26 * Ardelle Fan <ardelle.fan@intel.com> 27 * Ryan Layer <rmlayer@us.ibm.com> 28 * Kevin Gao <kevin.gao@intel.com> 29 */ 30 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33 #include <crypto/utils.h> 34 #include <linux/types.h> 35 #include <linux/kernel.h> 36 #include <linux/ip.h> 37 #include <linux/ipv6.h> 38 #include <linux/net.h> 39 #include <linux/inet.h> 40 #include <linux/slab.h> 41 #include <net/sock.h> 42 #include <net/proto_memory.h> 43 #include <net/inet_ecn.h> 44 #include <linux/skbuff.h> 45 #include <net/sctp/sctp.h> 46 #include <net/sctp/sm.h> 47 #include <net/sctp/structs.h> 48 49 #define CREATE_TRACE_POINTS 50 #include <trace/events/sctp.h> 51 52 static struct sctp_packet *sctp_abort_pkt_new( 53 struct net *net, 54 const struct sctp_endpoint *ep, 55 const struct sctp_association *asoc, 56 struct sctp_chunk *chunk, 57 const void *payload, size_t paylen); 58 static int sctp_eat_data(const struct sctp_association *asoc, 59 struct sctp_chunk *chunk, 60 struct sctp_cmd_seq *commands); 61 static struct sctp_packet *sctp_ootb_pkt_new( 62 struct net *net, 63 const struct sctp_association *asoc, 64 const struct sctp_chunk *chunk); 65 static void sctp_send_stale_cookie_err(struct net *net, 66 const struct sctp_endpoint *ep, 67 const struct sctp_association *asoc, 68 const struct sctp_chunk *chunk, 69 struct sctp_cmd_seq *commands, 70 struct sctp_chunk *err_chunk); 71 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 72 struct net *net, 73 const struct sctp_endpoint *ep, 74 const struct sctp_association *asoc, 75 const union sctp_subtype type, 76 void *arg, 77 struct sctp_cmd_seq *commands); 78 static enum sctp_disposition sctp_sf_shut_8_4_5( 79 struct net *net, 80 const struct sctp_endpoint *ep, 81 const struct sctp_association *asoc, 82 const union sctp_subtype type, 83 void *arg, 84 struct sctp_cmd_seq *commands); 85 static enum sctp_disposition sctp_sf_tabort_8_4_8( 86 struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const union sctp_subtype type, 90 void *arg, 91 struct sctp_cmd_seq *commands); 92 static enum sctp_disposition sctp_sf_new_encap_port( 93 struct net *net, 94 const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const union sctp_subtype type, 97 void *arg, 98 struct sctp_cmd_seq *commands); 99 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 100 101 static enum sctp_disposition sctp_stop_t1_and_abort( 102 struct net *net, 103 struct sctp_cmd_seq *commands, 104 __be16 error, int sk_err, 105 const struct sctp_association *asoc, 106 struct sctp_transport *transport); 107 108 static enum sctp_disposition sctp_sf_abort_violation( 109 struct net *net, 110 const struct sctp_endpoint *ep, 111 const struct sctp_association *asoc, 112 void *arg, 113 struct sctp_cmd_seq *commands, 114 const __u8 *payload, 115 const size_t paylen); 116 117 static enum sctp_disposition sctp_sf_violation_chunklen( 118 struct net *net, 119 const struct sctp_endpoint *ep, 120 const struct sctp_association *asoc, 121 const union sctp_subtype type, 122 void *arg, 123 struct sctp_cmd_seq *commands); 124 125 static enum sctp_disposition sctp_sf_violation_paramlen( 126 struct net *net, 127 const struct sctp_endpoint *ep, 128 const struct sctp_association *asoc, 129 const union sctp_subtype type, 130 void *arg, void *ext, 131 struct sctp_cmd_seq *commands); 132 133 static enum sctp_disposition sctp_sf_violation_ctsn( 134 struct net *net, 135 const struct sctp_endpoint *ep, 136 const struct sctp_association *asoc, 137 const union sctp_subtype type, 138 void *arg, 139 struct sctp_cmd_seq *commands); 140 141 static enum sctp_disposition sctp_sf_violation_chunk( 142 struct net *net, 143 const struct sctp_endpoint *ep, 144 const struct sctp_association *asoc, 145 const union sctp_subtype type, 146 void *arg, 147 struct sctp_cmd_seq *commands); 148 149 static enum sctp_ierror sctp_sf_authenticate( 150 const struct sctp_association *asoc, 151 struct sctp_chunk *chunk); 152 153 static enum sctp_disposition __sctp_sf_do_9_1_abort( 154 struct net *net, 155 const struct sctp_endpoint *ep, 156 const struct sctp_association *asoc, 157 const union sctp_subtype type, 158 void *arg, 159 struct sctp_cmd_seq *commands); 160 161 static enum sctp_disposition 162 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 163 const struct sctp_association *asoc, 164 const union sctp_subtype type, void *arg, 165 struct sctp_cmd_seq *commands); 166 167 /* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: true = Valid length 171 * false = Invalid length 172 * 173 */ 174 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 175 __u16 required_length) 176 { 177 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 178 179 /* Previously already marked? */ 180 if (unlikely(chunk->pdiscard)) 181 return false; 182 if (unlikely(chunk_length < required_length)) 183 return false; 184 185 return true; 186 } 187 188 /* Check for format error in an ABORT chunk */ 189 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk) 190 { 191 struct sctp_errhdr *err; 192 193 sctp_walk_errors(err, chunk->chunk_hdr); 194 195 return (void *)err == (void *)chunk->chunk_end; 196 } 197 198 /********************************************************** 199 * These are the state functions for handling chunk events. 200 **********************************************************/ 201 202 /* 203 * Process the final SHUTDOWN COMPLETE. 204 * 205 * Section: 4 (C) (diagram), 9.2 206 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 207 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 208 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 209 * should stop the T2-shutdown timer and remove all knowledge of the 210 * association (and thus the association enters the CLOSED state). 211 * 212 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 213 * C) Rules for packet carrying SHUTDOWN COMPLETE: 214 * ... 215 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 216 * if the Verification Tag field of the packet matches its own tag and 217 * the T bit is not set 218 * OR 219 * it is set to its peer's tag and the T bit is set in the Chunk 220 * Flags. 221 * Otherwise, the receiver MUST silently discard the packet 222 * and take no further action. An endpoint MUST ignore the 223 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 224 * 225 * Inputs 226 * (endpoint, asoc, chunk) 227 * 228 * Outputs 229 * (asoc, reply_msg, msg_up, timers, counters) 230 * 231 * The return value is the disposition of the chunk. 232 */ 233 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 234 const struct sctp_endpoint *ep, 235 const struct sctp_association *asoc, 236 const union sctp_subtype type, 237 void *arg, struct sctp_cmd_seq *commands) 238 { 239 struct sctp_chunk *chunk = arg; 240 struct sctp_ulpevent *ev; 241 242 if (!sctp_vtag_verify_either(chunk, asoc)) 243 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 244 245 /* RFC 2960 6.10 Bundling 246 * 247 * An endpoint MUST NOT bundle INIT, INIT ACK or 248 * SHUTDOWN COMPLETE with any other chunks. 249 */ 250 if (!chunk->singleton) 251 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 252 253 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 254 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 255 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 256 commands); 257 258 /* RFC 2960 10.2 SCTP-to-ULP 259 * 260 * H) SHUTDOWN COMPLETE notification 261 * 262 * When SCTP completes the shutdown procedures (section 9.2) this 263 * notification is passed to the upper layer. 264 */ 265 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 266 0, 0, 0, NULL, GFP_ATOMIC); 267 if (ev) 268 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 269 SCTP_ULPEVENT(ev)); 270 271 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 272 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 273 * not the chunk should be discarded. If the endpoint is in 274 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 275 * T2-shutdown timer and remove all knowledge of the 276 * association (and thus the association enters the CLOSED 277 * state). 278 */ 279 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 280 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 281 282 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 283 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 284 285 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 286 SCTP_STATE(SCTP_STATE_CLOSED)); 287 288 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 289 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 290 291 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 292 293 return SCTP_DISPOSITION_DELETE_TCB; 294 } 295 296 /* 297 * Respond to a normal INIT chunk. 298 * We are the side that is being asked for an association. 299 * 300 * Section: 5.1 Normal Establishment of an Association, B 301 * B) "Z" shall respond immediately with an INIT ACK chunk. The 302 * destination IP address of the INIT ACK MUST be set to the source 303 * IP address of the INIT to which this INIT ACK is responding. In 304 * the response, besides filling in other parameters, "Z" must set the 305 * Verification Tag field to Tag_A, and also provide its own 306 * Verification Tag (Tag_Z) in the Initiate Tag field. 307 * 308 * Verification Tag: Must be 0. 309 * 310 * Inputs 311 * (endpoint, asoc, chunk) 312 * 313 * Outputs 314 * (asoc, reply_msg, msg_up, timers, counters) 315 * 316 * The return value is the disposition of the chunk. 317 */ 318 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 319 const struct sctp_endpoint *ep, 320 const struct sctp_association *asoc, 321 const union sctp_subtype type, 322 void *arg, 323 struct sctp_cmd_seq *commands) 324 { 325 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 326 struct sctp_unrecognized_param *unk_param; 327 struct sctp_association *new_asoc; 328 struct sctp_packet *packet; 329 int len; 330 331 /* 6.10 Bundling 332 * An endpoint MUST NOT bundle INIT, INIT ACK or 333 * SHUTDOWN COMPLETE with any other chunks. 334 * 335 * IG Section 2.11.2 336 * Furthermore, we require that the receiver of an INIT chunk MUST 337 * enforce these rules by silently discarding an arriving packet 338 * with an INIT chunk that is bundled with other chunks. 339 */ 340 if (!chunk->singleton) 341 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 342 343 /* Make sure that the INIT chunk has a valid length. 344 * Normally, this would cause an ABORT with a Protocol Violation 345 * error, but since we don't have an association, we'll 346 * just discard the packet. 347 */ 348 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 349 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 350 351 /* If the packet is an OOTB packet which is temporarily on the 352 * control endpoint, respond with an ABORT. 353 */ 354 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 355 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 356 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 357 } 358 359 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 360 * Tag. 361 */ 362 if (chunk->sctp_hdr->vtag != 0) 363 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 364 365 /* If the INIT is coming toward a closing socket, we'll send back 366 * and ABORT. Essentially, this catches the race of INIT being 367 * backloged to the socket at the same time as the user issues close(). 368 * Since the socket and all its associations are going away, we 369 * can treat this OOTB 370 */ 371 if (sctp_sstate(ep->base.sk, CLOSING)) 372 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 373 374 /* Verify the INIT chunk before processing it. */ 375 err_chunk = NULL; 376 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 377 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 378 &err_chunk)) { 379 /* This chunk contains fatal error. It is to be discarded. 380 * Send an ABORT, with causes if there is any. 381 */ 382 if (err_chunk) { 383 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 384 (__u8 *)(err_chunk->chunk_hdr) + 385 sizeof(struct sctp_chunkhdr), 386 ntohs(err_chunk->chunk_hdr->length) - 387 sizeof(struct sctp_chunkhdr)); 388 389 sctp_chunk_free(err_chunk); 390 391 if (packet) { 392 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 393 SCTP_PACKET(packet)); 394 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 395 return SCTP_DISPOSITION_CONSUME; 396 } else { 397 return SCTP_DISPOSITION_NOMEM; 398 } 399 } else { 400 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 401 commands); 402 } 403 } 404 405 /* Grab the INIT header. */ 406 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 407 408 /* Tag the variable length parameters. */ 409 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 410 411 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 412 if (!new_asoc) 413 goto nomem; 414 415 /* Update socket peer label if first association. */ 416 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 417 sctp_association_free(new_asoc); 418 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 419 } 420 421 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 422 sctp_scope(sctp_source(chunk)), 423 GFP_ATOMIC) < 0) 424 goto nomem_init; 425 426 /* The call, sctp_process_init(), can fail on memory allocation. */ 427 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 428 (struct sctp_init_chunk *)chunk->chunk_hdr, 429 GFP_ATOMIC)) 430 goto nomem_init; 431 432 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 433 434 /* If there are errors need to be reported for unknown parameters, 435 * make sure to reserve enough room in the INIT ACK for them. 436 */ 437 len = 0; 438 if (err_chunk) 439 len = ntohs(err_chunk->chunk_hdr->length) - 440 sizeof(struct sctp_chunkhdr); 441 442 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 443 if (!repl) 444 goto nomem_init; 445 446 /* If there are errors need to be reported for unknown parameters, 447 * include them in the outgoing INIT ACK as "Unrecognized parameter" 448 * parameter. 449 */ 450 if (err_chunk) { 451 /* Get the "Unrecognized parameter" parameter(s) out of the 452 * ERROR chunk generated by sctp_verify_init(). Since the 453 * error cause code for "unknown parameter" and the 454 * "Unrecognized parameter" type is the same, we can 455 * construct the parameters in INIT ACK by copying the 456 * ERROR causes over. 457 */ 458 unk_param = (struct sctp_unrecognized_param *) 459 ((__u8 *)(err_chunk->chunk_hdr) + 460 sizeof(struct sctp_chunkhdr)); 461 /* Replace the cause code with the "Unrecognized parameter" 462 * parameter type. 463 */ 464 sctp_addto_chunk(repl, len, unk_param); 465 sctp_chunk_free(err_chunk); 466 } 467 468 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 469 470 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 471 472 /* 473 * Note: After sending out INIT ACK with the State Cookie parameter, 474 * "Z" MUST NOT allocate any resources, nor keep any states for the 475 * new association. Otherwise, "Z" will be vulnerable to resource 476 * attacks. 477 */ 478 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 479 480 return SCTP_DISPOSITION_DELETE_TCB; 481 482 nomem_init: 483 sctp_association_free(new_asoc); 484 nomem: 485 if (err_chunk) 486 sctp_chunk_free(err_chunk); 487 return SCTP_DISPOSITION_NOMEM; 488 } 489 490 /* 491 * Respond to a normal INIT ACK chunk. 492 * We are the side that is initiating the association. 493 * 494 * Section: 5.1 Normal Establishment of an Association, C 495 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 496 * timer and leave COOKIE-WAIT state. "A" shall then send the State 497 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 498 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 499 * 500 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 501 * DATA chunks, but it MUST be the first chunk in the packet and 502 * until the COOKIE ACK is returned the sender MUST NOT send any 503 * other packets to the peer. 504 * 505 * Verification Tag: 3.3.3 506 * If the value of the Initiate Tag in a received INIT ACK chunk is 507 * found to be 0, the receiver MUST treat it as an error and close the 508 * association by transmitting an ABORT. 509 * 510 * Inputs 511 * (endpoint, asoc, chunk) 512 * 513 * Outputs 514 * (asoc, reply_msg, msg_up, timers, counters) 515 * 516 * The return value is the disposition of the chunk. 517 */ 518 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 519 const struct sctp_endpoint *ep, 520 const struct sctp_association *asoc, 521 const union sctp_subtype type, 522 void *arg, 523 struct sctp_cmd_seq *commands) 524 { 525 struct sctp_init_chunk *initchunk; 526 struct sctp_chunk *chunk = arg; 527 struct sctp_chunk *err_chunk; 528 struct sctp_packet *packet; 529 530 if (!sctp_vtag_verify(chunk, asoc)) 531 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 532 533 /* 6.10 Bundling 534 * An endpoint MUST NOT bundle INIT, INIT ACK or 535 * SHUTDOWN COMPLETE with any other chunks. 536 */ 537 if (!chunk->singleton) 538 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 539 540 /* Make sure that the INIT-ACK chunk has a valid length */ 541 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 542 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 543 commands); 544 /* Grab the INIT header. */ 545 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 546 547 /* Verify the INIT chunk before processing it. */ 548 err_chunk = NULL; 549 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 550 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 551 &err_chunk)) { 552 553 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 554 555 /* This chunk contains fatal error. It is to be discarded. 556 * Send an ABORT, with causes. If there are no causes, 557 * then there wasn't enough memory. Just terminate 558 * the association. 559 */ 560 if (err_chunk) { 561 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 562 (__u8 *)(err_chunk->chunk_hdr) + 563 sizeof(struct sctp_chunkhdr), 564 ntohs(err_chunk->chunk_hdr->length) - 565 sizeof(struct sctp_chunkhdr)); 566 567 sctp_chunk_free(err_chunk); 568 569 if (packet) { 570 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 571 SCTP_PACKET(packet)); 572 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 573 error = SCTP_ERROR_INV_PARAM; 574 } 575 } 576 577 /* SCTP-AUTH, Section 6.3: 578 * It should be noted that if the receiver wants to tear 579 * down an association in an authenticated way only, the 580 * handling of malformed packets should not result in 581 * tearing down the association. 582 * 583 * This means that if we only want to abort associations 584 * in an authenticated way (i.e AUTH+ABORT), then we 585 * can't destroy this association just because the packet 586 * was malformed. 587 */ 588 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 589 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 590 591 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 592 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 593 asoc, chunk->transport); 594 } 595 596 /* Tag the variable length parameters. Note that we never 597 * convert the parameters in an INIT chunk. 598 */ 599 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 600 601 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 602 603 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 604 SCTP_PEER_INIT(initchunk)); 605 606 /* Reset init error count upon receipt of INIT-ACK. */ 607 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 608 609 /* 5.1 C) "A" shall stop the T1-init timer and leave 610 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 611 * timer, and enter the COOKIE-ECHOED state. 612 */ 613 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 614 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 615 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 616 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 617 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 618 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 619 620 /* SCTP-AUTH: generate the association shared keys so that 621 * we can potentially sign the COOKIE-ECHO. 622 */ 623 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 624 625 /* 5.1 C) "A" shall then send the State Cookie received in the 626 * INIT ACK chunk in a COOKIE ECHO chunk, ... 627 */ 628 /* If there is any errors to report, send the ERROR chunk generated 629 * for unknown parameters as well. 630 */ 631 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 632 SCTP_CHUNK(err_chunk)); 633 634 return SCTP_DISPOSITION_CONSUME; 635 } 636 637 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, 638 const struct sctp_association *asoc) 639 { 640 struct sctp_chunk auth; 641 642 if (!chunk->auth_chunk) 643 return true; 644 645 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 646 * is supposed to be authenticated and we have to do delayed 647 * authentication. We've just recreated the association using 648 * the information in the cookie and now it's much easier to 649 * do the authentication. 650 */ 651 652 /* Make sure that we and the peer are AUTH capable */ 653 if (!net->sctp.auth_enable || !asoc->peer.auth_capable) 654 return false; 655 656 /* set-up our fake chunk so that we can process it */ 657 auth.skb = chunk->auth_chunk; 658 auth.asoc = chunk->asoc; 659 auth.sctp_hdr = chunk->sctp_hdr; 660 auth.chunk_hdr = (struct sctp_chunkhdr *) 661 skb_push(chunk->auth_chunk, 662 sizeof(struct sctp_chunkhdr)); 663 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 664 auth.transport = chunk->transport; 665 666 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR; 667 } 668 669 /* 670 * Respond to a normal COOKIE ECHO chunk. 671 * We are the side that is being asked for an association. 672 * 673 * Section: 5.1 Normal Establishment of an Association, D 674 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 675 * with a COOKIE ACK chunk after building a TCB and moving to 676 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 677 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 678 * chunk MUST be the first chunk in the packet. 679 * 680 * IMPLEMENTATION NOTE: An implementation may choose to send the 681 * Communication Up notification to the SCTP user upon reception 682 * of a valid COOKIE ECHO chunk. 683 * 684 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 685 * D) Rules for packet carrying a COOKIE ECHO 686 * 687 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 688 * Initial Tag received in the INIT ACK. 689 * 690 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 691 * 692 * Inputs 693 * (endpoint, asoc, chunk) 694 * 695 * Outputs 696 * (asoc, reply_msg, msg_up, timers, counters) 697 * 698 * The return value is the disposition of the chunk. 699 */ 700 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 701 const struct sctp_endpoint *ep, 702 const struct sctp_association *asoc, 703 const union sctp_subtype type, 704 void *arg, 705 struct sctp_cmd_seq *commands) 706 { 707 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 708 struct sctp_association *new_asoc; 709 struct sctp_init_chunk *peer_init; 710 struct sctp_chunk *chunk = arg; 711 struct sctp_chunk *err_chk_p; 712 struct sctp_chunk *repl; 713 struct sock *sk; 714 int error = 0; 715 716 if (asoc && !sctp_vtag_verify(chunk, asoc)) 717 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 718 719 /* If the packet is an OOTB packet which is temporarily on the 720 * control endpoint, respond with an ABORT. 721 */ 722 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 723 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 724 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 725 } 726 727 /* Make sure that the COOKIE_ECHO chunk has a valid length. 728 * In this case, we check that we have enough for at least a 729 * chunk header. More detailed verification is done 730 * in sctp_unpack_cookie(). 731 */ 732 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 733 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 734 commands); 735 736 /* If the endpoint is not listening or if the number of associations 737 * on the TCP-style socket exceed the max backlog, respond with an 738 * ABORT. 739 */ 740 sk = ep->base.sk; 741 if (!sctp_sstate(sk, LISTENING) || 742 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 743 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 744 745 /* "Decode" the chunk. We have no optional parameters so we 746 * are in good shape. 747 */ 748 chunk->subh.cookie_hdr = 749 (struct sctp_signed_cookie *)chunk->skb->data; 750 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 751 sizeof(struct sctp_chunkhdr))) 752 goto nomem; 753 754 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 755 * "Z" will reply with a COOKIE ACK chunk after building a TCB 756 * and moving to the ESTABLISHED state. 757 */ 758 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 759 &err_chk_p); 760 761 /* FIXME: 762 * If the re-build failed, what is the proper error path 763 * from here? 764 * 765 * [We should abort the association. --piggy] 766 */ 767 if (!new_asoc) { 768 /* FIXME: Several errors are possible. A bad cookie should 769 * be silently discarded, but think about logging it too. 770 */ 771 switch (error) { 772 case -SCTP_IERROR_NOMEM: 773 goto nomem; 774 775 case -SCTP_IERROR_STALE_COOKIE: 776 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 777 err_chk_p); 778 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 779 780 case -SCTP_IERROR_BAD_SIG: 781 default: 782 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 783 } 784 } 785 786 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) { 787 sctp_association_free(new_asoc); 788 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 789 } 790 791 /* Delay state machine commands until later. 792 * 793 * Re-build the bind address for the association is done in 794 * the sctp_unpack_cookie() already. 795 */ 796 /* This is a brand-new association, so these are not yet side 797 * effects--it is safe to run them here. 798 */ 799 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 800 if (!sctp_process_init(new_asoc, chunk, 801 &chunk->subh.cookie_hdr->c.peer_addr, 802 peer_init, GFP_ATOMIC)) 803 goto nomem_init; 804 805 /* SCTP-AUTH: Now that we've populate required fields in 806 * sctp_process_init, set up the association shared keys as 807 * necessary so that we can potentially authenticate the ACK 808 */ 809 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 810 if (error) 811 goto nomem_init; 812 813 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) { 814 sctp_association_free(new_asoc); 815 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 816 } 817 818 repl = sctp_make_cookie_ack(new_asoc, chunk); 819 if (!repl) 820 goto nomem_init; 821 822 /* RFC 2960 5.1 Normal Establishment of an Association 823 * 824 * D) IMPLEMENTATION NOTE: An implementation may choose to 825 * send the Communication Up notification to the SCTP user 826 * upon reception of a valid COOKIE ECHO chunk. 827 */ 828 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 829 new_asoc->c.sinit_num_ostreams, 830 new_asoc->c.sinit_max_instreams, 831 NULL, GFP_ATOMIC); 832 if (!ev) 833 goto nomem_ev; 834 835 /* Sockets API Draft Section 5.3.1.6 836 * When a peer sends a Adaptation Layer Indication parameter , SCTP 837 * delivers this notification to inform the application that of the 838 * peers requested adaptation layer. 839 */ 840 if (new_asoc->peer.adaptation_ind) { 841 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 842 GFP_ATOMIC); 843 if (!ai_ev) 844 goto nomem_aiev; 845 } 846 847 if (!new_asoc->peer.auth_capable) { 848 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 849 SCTP_AUTH_NO_AUTH, 850 GFP_ATOMIC); 851 if (!auth_ev) 852 goto nomem_authev; 853 } 854 855 /* Add all the state machine commands now since we've created 856 * everything. This way we don't introduce memory corruptions 857 * during side-effect processing and correctly count established 858 * associations. 859 */ 860 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 861 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 862 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 863 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 864 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 865 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 866 867 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 868 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 869 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 870 871 /* This will send the COOKIE ACK */ 872 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 873 874 /* Queue the ASSOC_CHANGE event */ 875 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 876 877 /* Send up the Adaptation Layer Indication event */ 878 if (ai_ev) 879 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 880 SCTP_ULPEVENT(ai_ev)); 881 882 if (auth_ev) 883 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 884 SCTP_ULPEVENT(auth_ev)); 885 886 return SCTP_DISPOSITION_CONSUME; 887 888 nomem_authev: 889 sctp_ulpevent_free(ai_ev); 890 nomem_aiev: 891 sctp_ulpevent_free(ev); 892 nomem_ev: 893 sctp_chunk_free(repl); 894 nomem_init: 895 sctp_association_free(new_asoc); 896 nomem: 897 return SCTP_DISPOSITION_NOMEM; 898 } 899 900 /* 901 * Respond to a normal COOKIE ACK chunk. 902 * We are the side that is asking for an association. 903 * 904 * RFC 2960 5.1 Normal Establishment of an Association 905 * 906 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 907 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 908 * timer. It may also notify its ULP about the successful 909 * establishment of the association with a Communication Up 910 * notification (see Section 10). 911 * 912 * Verification Tag: 913 * Inputs 914 * (endpoint, asoc, chunk) 915 * 916 * Outputs 917 * (asoc, reply_msg, msg_up, timers, counters) 918 * 919 * The return value is the disposition of the chunk. 920 */ 921 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 922 const struct sctp_endpoint *ep, 923 const struct sctp_association *asoc, 924 const union sctp_subtype type, 925 void *arg, 926 struct sctp_cmd_seq *commands) 927 { 928 struct sctp_chunk *chunk = arg; 929 struct sctp_ulpevent *ev; 930 931 if (!sctp_vtag_verify(chunk, asoc)) 932 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 933 934 /* Set peer label for connection. */ 935 if (security_sctp_assoc_established((struct sctp_association *)asoc, 936 chunk->head_skb ?: chunk->skb)) 937 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 938 939 /* Verify that the chunk length for the COOKIE-ACK is OK. 940 * If we don't do this, any bundled chunks may be junked. 941 */ 942 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 943 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 944 commands); 945 946 /* Reset init error count upon receipt of COOKIE-ACK, 947 * to avoid problems with the management of this 948 * counter in stale cookie situations when a transition back 949 * from the COOKIE-ECHOED state to the COOKIE-WAIT 950 * state is performed. 951 */ 952 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 953 954 /* RFC 2960 5.1 Normal Establishment of an Association 955 * 956 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 957 * from the COOKIE-ECHOED state to the ESTABLISHED state, 958 * stopping the T1-cookie timer. 959 */ 960 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 961 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 962 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 963 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 964 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 965 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 966 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 967 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 968 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 969 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 970 971 /* It may also notify its ULP about the successful 972 * establishment of the association with a Communication Up 973 * notification (see Section 10). 974 */ 975 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 976 0, asoc->c.sinit_num_ostreams, 977 asoc->c.sinit_max_instreams, 978 NULL, GFP_ATOMIC); 979 980 if (!ev) 981 goto nomem; 982 983 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 984 985 /* Sockets API Draft Section 5.3.1.6 986 * When a peer sends a Adaptation Layer Indication parameter , SCTP 987 * delivers this notification to inform the application that of the 988 * peers requested adaptation layer. 989 */ 990 if (asoc->peer.adaptation_ind) { 991 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 992 if (!ev) 993 goto nomem; 994 995 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 996 SCTP_ULPEVENT(ev)); 997 } 998 999 if (!asoc->peer.auth_capable) { 1000 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 1001 GFP_ATOMIC); 1002 if (!ev) 1003 goto nomem; 1004 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1005 SCTP_ULPEVENT(ev)); 1006 } 1007 1008 return SCTP_DISPOSITION_CONSUME; 1009 nomem: 1010 return SCTP_DISPOSITION_NOMEM; 1011 } 1012 1013 /* Generate and sendout a heartbeat packet. */ 1014 static enum sctp_disposition sctp_sf_heartbeat( 1015 const struct sctp_endpoint *ep, 1016 const struct sctp_association *asoc, 1017 const union sctp_subtype type, 1018 void *arg, 1019 struct sctp_cmd_seq *commands) 1020 { 1021 struct sctp_transport *transport = (struct sctp_transport *) arg; 1022 struct sctp_chunk *reply; 1023 1024 /* Send a heartbeat to our peer. */ 1025 reply = sctp_make_heartbeat(asoc, transport, 0); 1026 if (!reply) 1027 return SCTP_DISPOSITION_NOMEM; 1028 1029 /* Set rto_pending indicating that an RTT measurement 1030 * is started with this heartbeat chunk. 1031 */ 1032 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1033 SCTP_TRANSPORT(transport)); 1034 1035 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1036 return SCTP_DISPOSITION_CONSUME; 1037 } 1038 1039 /* Generate a HEARTBEAT packet on the given transport. */ 1040 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1041 const struct sctp_endpoint *ep, 1042 const struct sctp_association *asoc, 1043 const union sctp_subtype type, 1044 void *arg, 1045 struct sctp_cmd_seq *commands) 1046 { 1047 struct sctp_transport *transport = (struct sctp_transport *) arg; 1048 1049 if (asoc->overall_error_count >= asoc->max_retrans) { 1050 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1051 SCTP_ERROR(ETIMEDOUT)); 1052 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1053 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1054 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1055 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1056 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1057 return SCTP_DISPOSITION_DELETE_TCB; 1058 } 1059 1060 /* Section 3.3.5. 1061 * The Sender-specific Heartbeat Info field should normally include 1062 * information about the sender's current time when this HEARTBEAT 1063 * chunk is sent and the destination transport address to which this 1064 * HEARTBEAT is sent (see Section 8.3). 1065 */ 1066 1067 if (transport->param_flags & SPP_HB_ENABLE) { 1068 if (SCTP_DISPOSITION_NOMEM == 1069 sctp_sf_heartbeat(ep, asoc, type, arg, 1070 commands)) 1071 return SCTP_DISPOSITION_NOMEM; 1072 1073 /* Set transport error counter and association error counter 1074 * when sending heartbeat. 1075 */ 1076 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1077 SCTP_TRANSPORT(transport)); 1078 } 1079 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1080 SCTP_TRANSPORT(transport)); 1081 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1082 SCTP_TRANSPORT(transport)); 1083 1084 return SCTP_DISPOSITION_CONSUME; 1085 } 1086 1087 /* resend asoc strreset_chunk. */ 1088 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1089 const struct sctp_endpoint *ep, 1090 const struct sctp_association *asoc, 1091 const union sctp_subtype type, 1092 void *arg, 1093 struct sctp_cmd_seq *commands) 1094 { 1095 struct sctp_transport *transport = arg; 1096 1097 if (asoc->overall_error_count >= asoc->max_retrans) { 1098 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1099 SCTP_ERROR(ETIMEDOUT)); 1100 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1101 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1102 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1103 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1104 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1105 return SCTP_DISPOSITION_DELETE_TCB; 1106 } 1107 1108 sctp_chunk_hold(asoc->strreset_chunk); 1109 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1110 SCTP_CHUNK(asoc->strreset_chunk)); 1111 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1112 1113 return SCTP_DISPOSITION_CONSUME; 1114 } 1115 1116 /* send hb chunk with padding for PLPMUTD. */ 1117 enum sctp_disposition sctp_sf_send_probe(struct net *net, 1118 const struct sctp_endpoint *ep, 1119 const struct sctp_association *asoc, 1120 const union sctp_subtype type, 1121 void *arg, 1122 struct sctp_cmd_seq *commands) 1123 { 1124 struct sctp_transport *transport = (struct sctp_transport *)arg; 1125 struct sctp_chunk *reply; 1126 1127 if (!sctp_transport_pl_enabled(transport)) 1128 return SCTP_DISPOSITION_CONSUME; 1129 1130 sctp_transport_pl_send(transport); 1131 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size); 1132 if (!reply) 1133 return SCTP_DISPOSITION_NOMEM; 1134 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1135 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE, 1136 SCTP_TRANSPORT(transport)); 1137 1138 return SCTP_DISPOSITION_CONSUME; 1139 } 1140 1141 /* 1142 * Process an heartbeat request. 1143 * 1144 * Section: 8.3 Path Heartbeat 1145 * The receiver of the HEARTBEAT should immediately respond with a 1146 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1147 * from the received HEARTBEAT chunk. 1148 * 1149 * Verification Tag: 8.5 Verification Tag [Normal verification] 1150 * When receiving an SCTP packet, the endpoint MUST ensure that the 1151 * value in the Verification Tag field of the received SCTP packet 1152 * matches its own Tag. If the received Verification Tag value does not 1153 * match the receiver's own tag value, the receiver shall silently 1154 * discard the packet and shall not process it any further except for 1155 * those cases listed in Section 8.5.1 below. 1156 * 1157 * Inputs 1158 * (endpoint, asoc, chunk) 1159 * 1160 * Outputs 1161 * (asoc, reply_msg, msg_up, timers, counters) 1162 * 1163 * The return value is the disposition of the chunk. 1164 */ 1165 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1166 const struct sctp_endpoint *ep, 1167 const struct sctp_association *asoc, 1168 const union sctp_subtype type, 1169 void *arg, struct sctp_cmd_seq *commands) 1170 { 1171 struct sctp_paramhdr *param_hdr; 1172 struct sctp_chunk *chunk = arg; 1173 struct sctp_chunk *reply; 1174 size_t paylen = 0; 1175 1176 if (!sctp_vtag_verify(chunk, asoc)) 1177 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1178 1179 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1180 if (!sctp_chunk_length_valid(chunk, 1181 sizeof(struct sctp_heartbeat_chunk))) 1182 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1183 commands); 1184 1185 /* 8.3 The receiver of the HEARTBEAT should immediately 1186 * respond with a HEARTBEAT ACK that contains the Heartbeat 1187 * Information field copied from the received HEARTBEAT chunk. 1188 */ 1189 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1190 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1191 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1192 1193 if (ntohs(param_hdr->length) > paylen) 1194 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1195 param_hdr, commands); 1196 1197 if (!pskb_pull(chunk->skb, paylen)) 1198 goto nomem; 1199 1200 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1201 if (!reply) 1202 goto nomem; 1203 1204 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1205 return SCTP_DISPOSITION_CONSUME; 1206 1207 nomem: 1208 return SCTP_DISPOSITION_NOMEM; 1209 } 1210 1211 /* 1212 * Process the returning HEARTBEAT ACK. 1213 * 1214 * Section: 8.3 Path Heartbeat 1215 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1216 * should clear the error counter of the destination transport 1217 * address to which the HEARTBEAT was sent, and mark the destination 1218 * transport address as active if it is not so marked. The endpoint may 1219 * optionally report to the upper layer when an inactive destination 1220 * address is marked as active due to the reception of the latest 1221 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1222 * clear the association overall error count as well (as defined 1223 * in section 8.1). 1224 * 1225 * The receiver of the HEARTBEAT ACK should also perform an RTT 1226 * measurement for that destination transport address using the time 1227 * value carried in the HEARTBEAT ACK chunk. 1228 * 1229 * Verification Tag: 8.5 Verification Tag [Normal verification] 1230 * 1231 * Inputs 1232 * (endpoint, asoc, chunk) 1233 * 1234 * Outputs 1235 * (asoc, reply_msg, msg_up, timers, counters) 1236 * 1237 * The return value is the disposition of the chunk. 1238 */ 1239 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1240 const struct sctp_endpoint *ep, 1241 const struct sctp_association *asoc, 1242 const union sctp_subtype type, 1243 void *arg, 1244 struct sctp_cmd_seq *commands) 1245 { 1246 struct sctp_sender_hb_info *hbinfo; 1247 struct sctp_chunk *chunk = arg; 1248 struct sctp_transport *link; 1249 unsigned long max_interval; 1250 union sctp_addr from_addr; 1251 1252 if (!sctp_vtag_verify(chunk, asoc)) 1253 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1254 1255 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1256 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1257 sizeof(*hbinfo))) 1258 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1259 commands); 1260 1261 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1262 /* Make sure that the length of the parameter is what we expect */ 1263 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1264 return SCTP_DISPOSITION_DISCARD; 1265 1266 from_addr = hbinfo->daddr; 1267 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1268 1269 /* This should never happen, but lets log it if so. */ 1270 if (unlikely(!link)) { 1271 if (from_addr.sa.sa_family == AF_INET6) { 1272 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1273 __func__, 1274 asoc, 1275 &from_addr.v6.sin6_addr); 1276 } else { 1277 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1278 __func__, 1279 asoc, 1280 &from_addr.v4.sin_addr.s_addr); 1281 } 1282 return SCTP_DISPOSITION_DISCARD; 1283 } 1284 1285 /* Validate the 64-bit random nonce. */ 1286 if (hbinfo->hb_nonce != link->hb_nonce) 1287 return SCTP_DISPOSITION_DISCARD; 1288 1289 if (hbinfo->probe_size) { 1290 if (hbinfo->probe_size != link->pl.probe_size || 1291 !sctp_transport_pl_enabled(link)) 1292 return SCTP_DISPOSITION_DISCARD; 1293 1294 if (sctp_transport_pl_recv(link)) 1295 return SCTP_DISPOSITION_CONSUME; 1296 1297 return sctp_sf_send_probe(net, ep, asoc, type, link, commands); 1298 } 1299 1300 max_interval = link->hbinterval + link->rto; 1301 1302 /* Check if the timestamp looks valid. */ 1303 if (time_after(hbinfo->sent_at, jiffies) || 1304 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1305 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1306 "for transport:%p\n", __func__, link); 1307 1308 return SCTP_DISPOSITION_DISCARD; 1309 } 1310 1311 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1312 * the HEARTBEAT should clear the error counter of the 1313 * destination transport address to which the HEARTBEAT was 1314 * sent and mark the destination transport address as active if 1315 * it is not so marked. 1316 */ 1317 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1318 1319 return SCTP_DISPOSITION_CONSUME; 1320 } 1321 1322 /* Helper function to send out an abort for the restart 1323 * condition. 1324 */ 1325 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1326 struct sctp_chunk *init, 1327 struct sctp_cmd_seq *commands) 1328 { 1329 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1330 union sctp_addr_param *addrparm; 1331 struct sctp_errhdr *errhdr; 1332 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1333 struct sctp_endpoint *ep; 1334 struct sctp_packet *pkt; 1335 int len; 1336 1337 /* Build the error on the stack. We are way to malloc crazy 1338 * throughout the code today. 1339 */ 1340 errhdr = (struct sctp_errhdr *)buffer; 1341 addrparm = (union sctp_addr_param *)(errhdr + 1); 1342 1343 /* Copy into a parm format. */ 1344 len = af->to_addr_param(ssa, addrparm); 1345 len += sizeof(*errhdr); 1346 1347 errhdr->cause = SCTP_ERROR_RESTART; 1348 errhdr->length = htons(len); 1349 1350 /* Assign to the control socket. */ 1351 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1352 1353 /* Association is NULL since this may be a restart attack and we 1354 * want to send back the attacker's vtag. 1355 */ 1356 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1357 1358 if (!pkt) 1359 goto out; 1360 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1361 1362 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1363 1364 /* Discard the rest of the inbound packet. */ 1365 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1366 1367 out: 1368 /* Even if there is no memory, treat as a failure so 1369 * the packet will get dropped. 1370 */ 1371 return 0; 1372 } 1373 1374 static bool list_has_sctp_addr(const struct list_head *list, 1375 union sctp_addr *ipaddr) 1376 { 1377 struct sctp_transport *addr; 1378 1379 list_for_each_entry(addr, list, transports) { 1380 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1381 return true; 1382 } 1383 1384 return false; 1385 } 1386 /* A restart is occurring, check to make sure no new addresses 1387 * are being added as we may be under a takeover attack. 1388 */ 1389 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1390 const struct sctp_association *asoc, 1391 struct sctp_chunk *init, 1392 struct sctp_cmd_seq *commands) 1393 { 1394 struct net *net = new_asoc->base.net; 1395 struct sctp_transport *new_addr; 1396 int ret = 1; 1397 1398 /* Implementor's Guide - Section 5.2.2 1399 * ... 1400 * Before responding the endpoint MUST check to see if the 1401 * unexpected INIT adds new addresses to the association. If new 1402 * addresses are added to the association, the endpoint MUST respond 1403 * with an ABORT.. 1404 */ 1405 1406 /* Search through all current addresses and make sure 1407 * we aren't adding any new ones. 1408 */ 1409 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1410 transports) { 1411 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1412 &new_addr->ipaddr)) { 1413 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1414 commands); 1415 ret = 0; 1416 break; 1417 } 1418 } 1419 1420 /* Return success if all addresses were found. */ 1421 return ret; 1422 } 1423 1424 /* Populate the verification/tie tags based on overlapping INIT 1425 * scenario. 1426 * 1427 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1428 */ 1429 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1430 const struct sctp_association *asoc) 1431 { 1432 switch (asoc->state) { 1433 1434 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1435 1436 case SCTP_STATE_COOKIE_WAIT: 1437 new_asoc->c.my_vtag = asoc->c.my_vtag; 1438 new_asoc->c.my_ttag = asoc->c.my_vtag; 1439 new_asoc->c.peer_ttag = 0; 1440 break; 1441 1442 case SCTP_STATE_COOKIE_ECHOED: 1443 new_asoc->c.my_vtag = asoc->c.my_vtag; 1444 new_asoc->c.my_ttag = asoc->c.my_vtag; 1445 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1446 break; 1447 1448 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1449 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1450 */ 1451 default: 1452 new_asoc->c.my_ttag = asoc->c.my_vtag; 1453 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1454 break; 1455 } 1456 1457 /* Other parameters for the endpoint SHOULD be copied from the 1458 * existing parameters of the association (e.g. number of 1459 * outbound streams) into the INIT ACK and cookie. 1460 */ 1461 new_asoc->rwnd = asoc->rwnd; 1462 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1463 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1464 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1465 } 1466 1467 /* 1468 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1469 * handling action. 1470 * 1471 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1472 * 1473 * Returns value representing action to be taken. These action values 1474 * correspond to Action/Description values in RFC 2960, Table 2. 1475 */ 1476 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1477 const struct sctp_association *asoc) 1478 { 1479 /* In this case, the peer may have restarted. */ 1480 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1481 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1482 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1483 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1484 return 'A'; 1485 1486 /* Collision case B. */ 1487 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1488 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1489 (0 == asoc->c.peer_vtag))) { 1490 return 'B'; 1491 } 1492 1493 /* Collision case D. */ 1494 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1495 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1496 return 'D'; 1497 1498 /* Collision case C. */ 1499 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1500 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1501 (0 == new_asoc->c.my_ttag) && 1502 (0 == new_asoc->c.peer_ttag)) 1503 return 'C'; 1504 1505 /* No match to any of the special cases; discard this packet. */ 1506 return 'E'; 1507 } 1508 1509 /* Common helper routine for both duplicate and simultaneous INIT 1510 * chunk handling. 1511 */ 1512 static enum sctp_disposition sctp_sf_do_unexpected_init( 1513 struct net *net, 1514 const struct sctp_endpoint *ep, 1515 const struct sctp_association *asoc, 1516 const union sctp_subtype type, 1517 void *arg, 1518 struct sctp_cmd_seq *commands) 1519 { 1520 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1521 struct sctp_unrecognized_param *unk_param; 1522 struct sctp_association *new_asoc; 1523 enum sctp_disposition retval; 1524 struct sctp_packet *packet; 1525 int len; 1526 1527 /* 6.10 Bundling 1528 * An endpoint MUST NOT bundle INIT, INIT ACK or 1529 * SHUTDOWN COMPLETE with any other chunks. 1530 * 1531 * IG Section 2.11.2 1532 * Furthermore, we require that the receiver of an INIT chunk MUST 1533 * enforce these rules by silently discarding an arriving packet 1534 * with an INIT chunk that is bundled with other chunks. 1535 */ 1536 if (!chunk->singleton) 1537 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1538 1539 /* Make sure that the INIT chunk has a valid length. */ 1540 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1541 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1542 1543 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1544 * Tag. 1545 */ 1546 if (chunk->sctp_hdr->vtag != 0) 1547 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1548 1549 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port) 1550 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands); 1551 1552 /* Grab the INIT header. */ 1553 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1554 1555 /* Tag the variable length parameters. */ 1556 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1557 1558 /* Verify the INIT chunk before processing it. */ 1559 err_chunk = NULL; 1560 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1561 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1562 &err_chunk)) { 1563 /* This chunk contains fatal error. It is to be discarded. 1564 * Send an ABORT, with causes if there is any. 1565 */ 1566 if (err_chunk) { 1567 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1568 (__u8 *)(err_chunk->chunk_hdr) + 1569 sizeof(struct sctp_chunkhdr), 1570 ntohs(err_chunk->chunk_hdr->length) - 1571 sizeof(struct sctp_chunkhdr)); 1572 1573 if (packet) { 1574 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1575 SCTP_PACKET(packet)); 1576 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1577 retval = SCTP_DISPOSITION_CONSUME; 1578 } else { 1579 retval = SCTP_DISPOSITION_NOMEM; 1580 } 1581 goto cleanup; 1582 } else { 1583 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1584 commands); 1585 } 1586 } 1587 1588 /* 1589 * Other parameters for the endpoint SHOULD be copied from the 1590 * existing parameters of the association (e.g. number of 1591 * outbound streams) into the INIT ACK and cookie. 1592 * FIXME: We are copying parameters from the endpoint not the 1593 * association. 1594 */ 1595 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1596 if (!new_asoc) 1597 goto nomem; 1598 1599 /* Update socket peer label if first association. */ 1600 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 1601 sctp_association_free(new_asoc); 1602 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1603 } 1604 1605 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1606 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1607 goto nomem; 1608 1609 /* In the outbound INIT ACK the endpoint MUST copy its current 1610 * Verification Tag and Peers Verification tag into a reserved 1611 * place (local tie-tag and per tie-tag) within the state cookie. 1612 */ 1613 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1614 (struct sctp_init_chunk *)chunk->chunk_hdr, 1615 GFP_ATOMIC)) 1616 goto nomem; 1617 1618 /* Make sure no new addresses are being added during the 1619 * restart. Do not do this check for COOKIE-WAIT state, 1620 * since there are no peer addresses to check against. 1621 * Upon return an ABORT will have been sent if needed. 1622 */ 1623 if (!sctp_state(asoc, COOKIE_WAIT)) { 1624 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1625 commands)) { 1626 retval = SCTP_DISPOSITION_CONSUME; 1627 goto nomem_retval; 1628 } 1629 } 1630 1631 sctp_tietags_populate(new_asoc, asoc); 1632 1633 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1634 1635 /* If there are errors need to be reported for unknown parameters, 1636 * make sure to reserve enough room in the INIT ACK for them. 1637 */ 1638 len = 0; 1639 if (err_chunk) { 1640 len = ntohs(err_chunk->chunk_hdr->length) - 1641 sizeof(struct sctp_chunkhdr); 1642 } 1643 1644 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1645 if (!repl) 1646 goto nomem; 1647 1648 /* If there are errors need to be reported for unknown parameters, 1649 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1650 * parameter. 1651 */ 1652 if (err_chunk) { 1653 /* Get the "Unrecognized parameter" parameter(s) out of the 1654 * ERROR chunk generated by sctp_verify_init(). Since the 1655 * error cause code for "unknown parameter" and the 1656 * "Unrecognized parameter" type is the same, we can 1657 * construct the parameters in INIT ACK by copying the 1658 * ERROR causes over. 1659 */ 1660 unk_param = (struct sctp_unrecognized_param *) 1661 ((__u8 *)(err_chunk->chunk_hdr) + 1662 sizeof(struct sctp_chunkhdr)); 1663 /* Replace the cause code with the "Unrecognized parameter" 1664 * parameter type. 1665 */ 1666 sctp_addto_chunk(repl, len, unk_param); 1667 } 1668 1669 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1670 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1671 1672 /* 1673 * Note: After sending out INIT ACK with the State Cookie parameter, 1674 * "Z" MUST NOT allocate any resources for this new association. 1675 * Otherwise, "Z" will be vulnerable to resource attacks. 1676 */ 1677 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1678 retval = SCTP_DISPOSITION_CONSUME; 1679 1680 return retval; 1681 1682 nomem: 1683 retval = SCTP_DISPOSITION_NOMEM; 1684 nomem_retval: 1685 if (new_asoc) 1686 sctp_association_free(new_asoc); 1687 cleanup: 1688 if (err_chunk) 1689 sctp_chunk_free(err_chunk); 1690 return retval; 1691 } 1692 1693 /* 1694 * Handle simultaneous INIT. 1695 * This means we started an INIT and then we got an INIT request from 1696 * our peer. 1697 * 1698 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1699 * This usually indicates an initialization collision, i.e., each 1700 * endpoint is attempting, at about the same time, to establish an 1701 * association with the other endpoint. 1702 * 1703 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1704 * endpoint MUST respond with an INIT ACK using the same parameters it 1705 * sent in its original INIT chunk (including its Verification Tag, 1706 * unchanged). These original parameters are combined with those from the 1707 * newly received INIT chunk. The endpoint shall also generate a State 1708 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1709 * INIT to calculate the State Cookie. 1710 * 1711 * After that, the endpoint MUST NOT change its state, the T1-init 1712 * timer shall be left running and the corresponding TCB MUST NOT be 1713 * destroyed. The normal procedures for handling State Cookies when 1714 * a TCB exists will resolve the duplicate INITs to a single association. 1715 * 1716 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1717 * its Tie-Tags with the Tag information of itself and its peer (see 1718 * section 5.2.2 for a description of the Tie-Tags). 1719 * 1720 * Verification Tag: Not explicit, but an INIT can not have a valid 1721 * verification tag, so we skip the check. 1722 * 1723 * Inputs 1724 * (endpoint, asoc, chunk) 1725 * 1726 * Outputs 1727 * (asoc, reply_msg, msg_up, timers, counters) 1728 * 1729 * The return value is the disposition of the chunk. 1730 */ 1731 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1732 struct net *net, 1733 const struct sctp_endpoint *ep, 1734 const struct sctp_association *asoc, 1735 const union sctp_subtype type, 1736 void *arg, 1737 struct sctp_cmd_seq *commands) 1738 { 1739 /* Call helper to do the real work for both simultaneous and 1740 * duplicate INIT chunk handling. 1741 */ 1742 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1743 } 1744 1745 /* 1746 * Handle duplicated INIT messages. These are usually delayed 1747 * restransmissions. 1748 * 1749 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1750 * COOKIE-ECHOED and COOKIE-WAIT 1751 * 1752 * Unless otherwise stated, upon reception of an unexpected INIT for 1753 * this association, the endpoint shall generate an INIT ACK with a 1754 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1755 * current Verification Tag and peer's Verification Tag into a reserved 1756 * place within the state cookie. We shall refer to these locations as 1757 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1758 * containing this INIT ACK MUST carry a Verification Tag value equal to 1759 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1760 * MUST contain a new Initiation Tag (randomly generated see Section 1761 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1762 * existing parameters of the association (e.g. number of outbound 1763 * streams) into the INIT ACK and cookie. 1764 * 1765 * After sending out the INIT ACK, the endpoint shall take no further 1766 * actions, i.e., the existing association, including its current state, 1767 * and the corresponding TCB MUST NOT be changed. 1768 * 1769 * Note: Only when a TCB exists and the association is not in a COOKIE- 1770 * WAIT state are the Tie-Tags populated. For a normal association INIT 1771 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1772 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1773 * State Cookie are populated as specified in section 5.2.1. 1774 * 1775 * Verification Tag: Not specified, but an INIT has no way of knowing 1776 * what the verification tag could be, so we ignore it. 1777 * 1778 * Inputs 1779 * (endpoint, asoc, chunk) 1780 * 1781 * Outputs 1782 * (asoc, reply_msg, msg_up, timers, counters) 1783 * 1784 * The return value is the disposition of the chunk. 1785 */ 1786 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1787 struct net *net, 1788 const struct sctp_endpoint *ep, 1789 const struct sctp_association *asoc, 1790 const union sctp_subtype type, 1791 void *arg, 1792 struct sctp_cmd_seq *commands) 1793 { 1794 /* Call helper to do the real work for both simultaneous and 1795 * duplicate INIT chunk handling. 1796 */ 1797 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1798 } 1799 1800 1801 /* 1802 * Unexpected INIT-ACK handler. 1803 * 1804 * Section 5.2.3 1805 * If an INIT ACK received by an endpoint in any state other than the 1806 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1807 * An unexpected INIT ACK usually indicates the processing of an old or 1808 * duplicated INIT chunk. 1809 */ 1810 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1811 struct net *net, 1812 const struct sctp_endpoint *ep, 1813 const struct sctp_association *asoc, 1814 const union sctp_subtype type, 1815 void *arg, 1816 struct sctp_cmd_seq *commands) 1817 { 1818 /* Per the above section, we'll discard the chunk if we have an 1819 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1820 */ 1821 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1822 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1823 else 1824 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1825 } 1826 1827 static int sctp_sf_do_assoc_update(struct sctp_association *asoc, 1828 struct sctp_association *new, 1829 struct sctp_cmd_seq *cmds) 1830 { 1831 struct net *net = asoc->base.net; 1832 struct sctp_chunk *abort; 1833 1834 if (!sctp_assoc_update(asoc, new)) 1835 return 0; 1836 1837 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr)); 1838 if (abort) { 1839 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 1840 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 1841 } 1842 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED)); 1843 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED, 1844 SCTP_PERR(SCTP_ERROR_RSRC_LOW)); 1845 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1846 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1847 1848 return -ENOMEM; 1849 } 1850 1851 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1852 * 1853 * Section 5.2.4 1854 * A) In this case, the peer may have restarted. 1855 */ 1856 static enum sctp_disposition sctp_sf_do_dupcook_a( 1857 struct net *net, 1858 const struct sctp_endpoint *ep, 1859 const struct sctp_association *asoc, 1860 struct sctp_chunk *chunk, 1861 struct sctp_cmd_seq *commands, 1862 struct sctp_association *new_asoc) 1863 { 1864 struct sctp_init_chunk *peer_init; 1865 enum sctp_disposition disposition; 1866 struct sctp_ulpevent *ev; 1867 struct sctp_chunk *repl; 1868 struct sctp_chunk *err; 1869 1870 /* new_asoc is a brand-new association, so these are not yet 1871 * side effects--it is safe to run them here. 1872 */ 1873 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1874 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1875 GFP_ATOMIC)) 1876 goto nomem; 1877 1878 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1879 goto nomem; 1880 1881 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1882 return SCTP_DISPOSITION_DISCARD; 1883 1884 /* Make sure no new addresses are being added during the 1885 * restart. Though this is a pretty complicated attack 1886 * since you'd have to get inside the cookie. 1887 */ 1888 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1889 return SCTP_DISPOSITION_CONSUME; 1890 1891 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1892 * the peer has restarted (Action A), it MUST NOT setup a new 1893 * association but instead resend the SHUTDOWN ACK and send an ERROR 1894 * chunk with a "Cookie Received while Shutting Down" error cause to 1895 * its peer. 1896 */ 1897 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1898 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc, 1899 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1900 chunk, commands); 1901 if (SCTP_DISPOSITION_NOMEM == disposition) 1902 goto nomem; 1903 1904 err = sctp_make_op_error(asoc, chunk, 1905 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1906 NULL, 0, 0); 1907 if (err) 1908 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1909 SCTP_CHUNK(err)); 1910 1911 return SCTP_DISPOSITION_CONSUME; 1912 } 1913 1914 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1915 * data. Consider the optional choice of resending of this data. 1916 */ 1917 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1918 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1919 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1920 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1921 1922 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1923 * and ASCONF-ACK cache. 1924 */ 1925 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1926 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1927 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1928 1929 /* Update the content of current association. */ 1930 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1931 goto nomem; 1932 1933 repl = sctp_make_cookie_ack(asoc, chunk); 1934 if (!repl) 1935 goto nomem; 1936 1937 /* Report association restart to upper layer. */ 1938 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1939 asoc->c.sinit_num_ostreams, 1940 asoc->c.sinit_max_instreams, 1941 NULL, GFP_ATOMIC); 1942 if (!ev) 1943 goto nomem_ev; 1944 1945 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1946 if ((sctp_state(asoc, SHUTDOWN_PENDING) || 1947 sctp_state(asoc, SHUTDOWN_SENT)) && 1948 (sctp_sstate(asoc->base.sk, CLOSING) || 1949 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1950 /* If the socket has been closed by user, don't 1951 * transition to ESTABLISHED. Instead trigger SHUTDOWN 1952 * bundled with COOKIE_ACK. 1953 */ 1954 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1955 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1956 SCTP_ST_CHUNK(0), repl, 1957 commands); 1958 } else { 1959 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1960 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1961 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1962 } 1963 return SCTP_DISPOSITION_CONSUME; 1964 1965 nomem_ev: 1966 sctp_chunk_free(repl); 1967 nomem: 1968 return SCTP_DISPOSITION_NOMEM; 1969 } 1970 1971 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1972 * 1973 * Section 5.2.4 1974 * B) In this case, both sides may be attempting to start an association 1975 * at about the same time but the peer endpoint started its INIT 1976 * after responding to the local endpoint's INIT 1977 */ 1978 /* This case represents an initialization collision. */ 1979 static enum sctp_disposition sctp_sf_do_dupcook_b( 1980 struct net *net, 1981 const struct sctp_endpoint *ep, 1982 const struct sctp_association *asoc, 1983 struct sctp_chunk *chunk, 1984 struct sctp_cmd_seq *commands, 1985 struct sctp_association *new_asoc) 1986 { 1987 struct sctp_init_chunk *peer_init; 1988 struct sctp_chunk *repl; 1989 1990 /* new_asoc is a brand-new association, so these are not yet 1991 * side effects--it is safe to run them here. 1992 */ 1993 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1994 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1995 GFP_ATOMIC)) 1996 goto nomem; 1997 1998 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1999 goto nomem; 2000 2001 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 2002 return SCTP_DISPOSITION_DISCARD; 2003 2004 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2005 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2006 if (asoc->state < SCTP_STATE_ESTABLISHED) 2007 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2008 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 2009 2010 /* Update the content of current association. */ 2011 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 2012 goto nomem; 2013 2014 repl = sctp_make_cookie_ack(asoc, chunk); 2015 if (!repl) 2016 goto nomem; 2017 2018 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2019 2020 /* RFC 2960 5.1 Normal Establishment of an Association 2021 * 2022 * D) IMPLEMENTATION NOTE: An implementation may choose to 2023 * send the Communication Up notification to the SCTP user 2024 * upon reception of a valid COOKIE ECHO chunk. 2025 * 2026 * Sadly, this needs to be implemented as a side-effect, because 2027 * we are not guaranteed to have set the association id of the real 2028 * association and so these notifications need to be delayed until 2029 * the association id is allocated. 2030 */ 2031 2032 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 2033 2034 /* Sockets API Draft Section 5.3.1.6 2035 * When a peer sends a Adaptation Layer Indication parameter , SCTP 2036 * delivers this notification to inform the application that of the 2037 * peers requested adaptation layer. 2038 * 2039 * This also needs to be done as a side effect for the same reason as 2040 * above. 2041 */ 2042 if (asoc->peer.adaptation_ind) 2043 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 2044 2045 if (!asoc->peer.auth_capable) 2046 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 2047 2048 return SCTP_DISPOSITION_CONSUME; 2049 2050 nomem: 2051 return SCTP_DISPOSITION_NOMEM; 2052 } 2053 2054 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 2055 * 2056 * Section 5.2.4 2057 * C) In this case, the local endpoint's cookie has arrived late. 2058 * Before it arrived, the local endpoint sent an INIT and received an 2059 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 2060 * but a new tag of its own. 2061 */ 2062 /* This case represents an initialization collision. */ 2063 static enum sctp_disposition sctp_sf_do_dupcook_c( 2064 struct net *net, 2065 const struct sctp_endpoint *ep, 2066 const struct sctp_association *asoc, 2067 struct sctp_chunk *chunk, 2068 struct sctp_cmd_seq *commands, 2069 struct sctp_association *new_asoc) 2070 { 2071 /* The cookie should be silently discarded. 2072 * The endpoint SHOULD NOT change states and should leave 2073 * any timers running. 2074 */ 2075 return SCTP_DISPOSITION_DISCARD; 2076 } 2077 2078 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 2079 * 2080 * Section 5.2.4 2081 * 2082 * D) When both local and remote tags match the endpoint should always 2083 * enter the ESTABLISHED state, if it has not already done so. 2084 */ 2085 /* This case represents an initialization collision. */ 2086 static enum sctp_disposition sctp_sf_do_dupcook_d( 2087 struct net *net, 2088 const struct sctp_endpoint *ep, 2089 const struct sctp_association *asoc, 2090 struct sctp_chunk *chunk, 2091 struct sctp_cmd_seq *commands, 2092 struct sctp_association *new_asoc) 2093 { 2094 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2095 struct sctp_chunk *repl; 2096 2097 /* Clarification from Implementor's Guide: 2098 * D) When both local and remote tags match the endpoint should 2099 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2100 * It should stop any cookie timer that may be running and send 2101 * a COOKIE ACK. 2102 */ 2103 2104 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2105 return SCTP_DISPOSITION_DISCARD; 2106 2107 /* Don't accidentally move back into established state. */ 2108 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2109 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2110 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2111 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2112 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2113 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2114 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2115 SCTP_NULL()); 2116 2117 /* RFC 2960 5.1 Normal Establishment of an Association 2118 * 2119 * D) IMPLEMENTATION NOTE: An implementation may choose 2120 * to send the Communication Up notification to the 2121 * SCTP user upon reception of a valid COOKIE 2122 * ECHO chunk. 2123 */ 2124 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2125 SCTP_COMM_UP, 0, 2126 asoc->c.sinit_num_ostreams, 2127 asoc->c.sinit_max_instreams, 2128 NULL, GFP_ATOMIC); 2129 if (!ev) 2130 goto nomem; 2131 2132 /* Sockets API Draft Section 5.3.1.6 2133 * When a peer sends a Adaptation Layer Indication parameter, 2134 * SCTP delivers this notification to inform the application 2135 * that of the peers requested adaptation layer. 2136 */ 2137 if (asoc->peer.adaptation_ind) { 2138 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2139 GFP_ATOMIC); 2140 if (!ai_ev) 2141 goto nomem; 2142 2143 } 2144 2145 if (!asoc->peer.auth_capable) { 2146 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2147 SCTP_AUTH_NO_AUTH, 2148 GFP_ATOMIC); 2149 if (!auth_ev) 2150 goto nomem; 2151 } 2152 } 2153 2154 repl = sctp_make_cookie_ack(asoc, chunk); 2155 if (!repl) 2156 goto nomem; 2157 2158 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2159 2160 if (ev) 2161 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2162 SCTP_ULPEVENT(ev)); 2163 if (ai_ev) 2164 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2165 SCTP_ULPEVENT(ai_ev)); 2166 if (auth_ev) 2167 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2168 SCTP_ULPEVENT(auth_ev)); 2169 2170 return SCTP_DISPOSITION_CONSUME; 2171 2172 nomem: 2173 if (auth_ev) 2174 sctp_ulpevent_free(auth_ev); 2175 if (ai_ev) 2176 sctp_ulpevent_free(ai_ev); 2177 if (ev) 2178 sctp_ulpevent_free(ev); 2179 return SCTP_DISPOSITION_NOMEM; 2180 } 2181 2182 /* 2183 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2184 * chunk was retransmitted and then delayed in the network. 2185 * 2186 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2187 * 2188 * Verification Tag: None. Do cookie validation. 2189 * 2190 * Inputs 2191 * (endpoint, asoc, chunk) 2192 * 2193 * Outputs 2194 * (asoc, reply_msg, msg_up, timers, counters) 2195 * 2196 * The return value is the disposition of the chunk. 2197 */ 2198 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2199 struct net *net, 2200 const struct sctp_endpoint *ep, 2201 const struct sctp_association *asoc, 2202 const union sctp_subtype type, 2203 void *arg, 2204 struct sctp_cmd_seq *commands) 2205 { 2206 struct sctp_association *new_asoc; 2207 struct sctp_chunk *chunk = arg; 2208 enum sctp_disposition retval; 2209 struct sctp_chunk *err_chk_p; 2210 int error = 0; 2211 char action; 2212 2213 /* Make sure that the chunk has a valid length from the protocol 2214 * perspective. In this case check to make sure we have at least 2215 * enough for the chunk header. Cookie length verification is 2216 * done later. 2217 */ 2218 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) { 2219 if (!sctp_vtag_verify(chunk, asoc)) 2220 asoc = NULL; 2221 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); 2222 } 2223 2224 /* "Decode" the chunk. We have no optional parameters so we 2225 * are in good shape. 2226 */ 2227 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2228 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2229 sizeof(struct sctp_chunkhdr))) 2230 goto nomem; 2231 2232 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2233 * of a duplicate COOKIE ECHO match the Verification Tags of the 2234 * current association, consider the State Cookie valid even if 2235 * the lifespan is exceeded. 2236 */ 2237 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2238 &err_chk_p); 2239 2240 /* FIXME: 2241 * If the re-build failed, what is the proper error path 2242 * from here? 2243 * 2244 * [We should abort the association. --piggy] 2245 */ 2246 if (!new_asoc) { 2247 /* FIXME: Several errors are possible. A bad cookie should 2248 * be silently discarded, but think about logging it too. 2249 */ 2250 switch (error) { 2251 case -SCTP_IERROR_NOMEM: 2252 goto nomem; 2253 2254 case -SCTP_IERROR_STALE_COOKIE: 2255 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2256 err_chk_p); 2257 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2258 case -SCTP_IERROR_BAD_SIG: 2259 default: 2260 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2261 } 2262 } 2263 2264 /* Set temp so that it won't be added into hashtable */ 2265 new_asoc->temp = 1; 2266 2267 /* Compare the tie_tag in cookie with the verification tag of 2268 * current association. 2269 */ 2270 action = sctp_tietags_compare(new_asoc, asoc); 2271 2272 /* In cases C and E the association doesn't enter the ESTABLISHED 2273 * state, so there is no need to call security_sctp_assoc_request(). 2274 */ 2275 switch (action) { 2276 case 'A': /* Association restart. */ 2277 case 'B': /* Collision case B. */ 2278 case 'D': /* Collision case D. */ 2279 /* Update socket peer label if first association. */ 2280 if (security_sctp_assoc_request((struct sctp_association *)asoc, 2281 chunk->head_skb ?: chunk->skb)) { 2282 sctp_association_free(new_asoc); 2283 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2284 } 2285 break; 2286 } 2287 2288 switch (action) { 2289 case 'A': /* Association restart. */ 2290 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2291 new_asoc); 2292 break; 2293 2294 case 'B': /* Collision case B. */ 2295 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2296 new_asoc); 2297 break; 2298 2299 case 'C': /* Collision case C. */ 2300 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2301 new_asoc); 2302 break; 2303 2304 case 'D': /* Collision case D. */ 2305 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2306 new_asoc); 2307 break; 2308 2309 default: /* Discard packet for all others. */ 2310 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2311 break; 2312 } 2313 2314 /* Delete the temporary new association. */ 2315 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2316 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2317 2318 /* Restore association pointer to provide SCTP command interpreter 2319 * with a valid context in case it needs to manipulate 2320 * the queues */ 2321 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2322 SCTP_ASOC((struct sctp_association *)asoc)); 2323 2324 return retval; 2325 2326 nomem: 2327 return SCTP_DISPOSITION_NOMEM; 2328 } 2329 2330 /* 2331 * Process an ABORT. (SHUTDOWN-PENDING state) 2332 * 2333 * See sctp_sf_do_9_1_abort(). 2334 */ 2335 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2336 struct net *net, 2337 const struct sctp_endpoint *ep, 2338 const struct sctp_association *asoc, 2339 const union sctp_subtype type, 2340 void *arg, 2341 struct sctp_cmd_seq *commands) 2342 { 2343 struct sctp_chunk *chunk = arg; 2344 2345 if (!sctp_vtag_verify_either(chunk, asoc)) 2346 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2347 2348 /* Make sure that the ABORT chunk has a valid length. 2349 * Since this is an ABORT chunk, we have to discard it 2350 * because of the following text: 2351 * RFC 2960, Section 3.3.7 2352 * If an endpoint receives an ABORT with a format error or for an 2353 * association that doesn't exist, it MUST silently discard it. 2354 * Because the length is "invalid", we can't really discard just 2355 * as we do not know its true length. So, to be safe, discard the 2356 * packet. 2357 */ 2358 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2359 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2360 2361 /* ADD-IP: Special case for ABORT chunks 2362 * F4) One special consideration is that ABORT Chunks arriving 2363 * destined to the IP address being deleted MUST be 2364 * ignored (see Section 5.3.1 for further details). 2365 */ 2366 if (SCTP_ADDR_DEL == 2367 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2368 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2369 2370 if (!sctp_err_chunk_valid(chunk)) 2371 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2372 2373 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2374 } 2375 2376 /* 2377 * Process an ABORT. (SHUTDOWN-SENT state) 2378 * 2379 * See sctp_sf_do_9_1_abort(). 2380 */ 2381 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2382 struct net *net, 2383 const struct sctp_endpoint *ep, 2384 const struct sctp_association *asoc, 2385 const union sctp_subtype type, 2386 void *arg, 2387 struct sctp_cmd_seq *commands) 2388 { 2389 struct sctp_chunk *chunk = arg; 2390 2391 if (!sctp_vtag_verify_either(chunk, asoc)) 2392 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2393 2394 /* Make sure that the ABORT chunk has a valid length. 2395 * Since this is an ABORT chunk, we have to discard it 2396 * because of the following text: 2397 * RFC 2960, Section 3.3.7 2398 * If an endpoint receives an ABORT with a format error or for an 2399 * association that doesn't exist, it MUST silently discard it. 2400 * Because the length is "invalid", we can't really discard just 2401 * as we do not know its true length. So, to be safe, discard the 2402 * packet. 2403 */ 2404 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2405 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2406 2407 /* ADD-IP: Special case for ABORT chunks 2408 * F4) One special consideration is that ABORT Chunks arriving 2409 * destined to the IP address being deleted MUST be 2410 * ignored (see Section 5.3.1 for further details). 2411 */ 2412 if (SCTP_ADDR_DEL == 2413 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2414 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2415 2416 if (!sctp_err_chunk_valid(chunk)) 2417 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2418 2419 /* Stop the T2-shutdown timer. */ 2420 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2421 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2422 2423 /* Stop the T5-shutdown guard timer. */ 2424 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2425 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2426 2427 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2428 } 2429 2430 /* 2431 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2432 * 2433 * See sctp_sf_do_9_1_abort(). 2434 */ 2435 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2436 struct net *net, 2437 const struct sctp_endpoint *ep, 2438 const struct sctp_association *asoc, 2439 const union sctp_subtype type, 2440 void *arg, 2441 struct sctp_cmd_seq *commands) 2442 { 2443 /* The same T2 timer, so we should be able to use 2444 * common function with the SHUTDOWN-SENT state. 2445 */ 2446 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2447 } 2448 2449 /* 2450 * Handle an Error received in COOKIE_ECHOED state. 2451 * 2452 * Only handle the error type of stale COOKIE Error, the other errors will 2453 * be ignored. 2454 * 2455 * Inputs 2456 * (endpoint, asoc, chunk) 2457 * 2458 * Outputs 2459 * (asoc, reply_msg, msg_up, timers, counters) 2460 * 2461 * The return value is the disposition of the chunk. 2462 */ 2463 enum sctp_disposition sctp_sf_cookie_echoed_err( 2464 struct net *net, 2465 const struct sctp_endpoint *ep, 2466 const struct sctp_association *asoc, 2467 const union sctp_subtype type, 2468 void *arg, 2469 struct sctp_cmd_seq *commands) 2470 { 2471 struct sctp_chunk *chunk = arg; 2472 struct sctp_errhdr *err; 2473 2474 if (!sctp_vtag_verify(chunk, asoc)) 2475 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2476 2477 /* Make sure that the ERROR chunk has a valid length. 2478 * The parameter walking depends on this as well. 2479 */ 2480 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2481 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2482 commands); 2483 2484 /* Process the error here */ 2485 /* FUTURE FIXME: When PR-SCTP related and other optional 2486 * parms are emitted, this will have to change to handle multiple 2487 * errors. 2488 */ 2489 sctp_walk_errors(err, chunk->chunk_hdr) { 2490 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2491 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2492 arg, commands); 2493 } 2494 2495 /* It is possible to have malformed error causes, and that 2496 * will cause us to end the walk early. However, since 2497 * we are discarding the packet, there should be no adverse 2498 * affects. 2499 */ 2500 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2501 } 2502 2503 /* 2504 * Handle a Stale COOKIE Error 2505 * 2506 * Section: 5.2.6 Handle Stale COOKIE Error 2507 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2508 * one of the following three alternatives. 2509 * ... 2510 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2511 * Preservative parameter requesting an extension to the lifetime of 2512 * the State Cookie. When calculating the time extension, an 2513 * implementation SHOULD use the RTT information measured based on the 2514 * previous COOKIE ECHO / ERROR exchange, and should add no more 2515 * than 1 second beyond the measured RTT, due to long State Cookie 2516 * lifetimes making the endpoint more subject to a replay attack. 2517 * 2518 * Verification Tag: Not explicit, but safe to ignore. 2519 * 2520 * Inputs 2521 * (endpoint, asoc, chunk) 2522 * 2523 * Outputs 2524 * (asoc, reply_msg, msg_up, timers, counters) 2525 * 2526 * The return value is the disposition of the chunk. 2527 */ 2528 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2529 struct net *net, 2530 const struct sctp_endpoint *ep, 2531 const struct sctp_association *asoc, 2532 const union sctp_subtype type, 2533 void *arg, 2534 struct sctp_cmd_seq *commands) 2535 { 2536 int attempts = asoc->init_err_counter + 1; 2537 struct sctp_chunk *chunk = arg, *reply; 2538 struct sctp_cookie_preserve_param bht; 2539 struct sctp_bind_addr *bp; 2540 struct sctp_errhdr *err; 2541 u32 stale; 2542 2543 if (attempts > asoc->max_init_attempts) { 2544 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2545 SCTP_ERROR(ETIMEDOUT)); 2546 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2547 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2548 return SCTP_DISPOSITION_DELETE_TCB; 2549 } 2550 2551 err = (struct sctp_errhdr *)(chunk->skb->data); 2552 2553 /* When calculating the time extension, an implementation 2554 * SHOULD use the RTT information measured based on the 2555 * previous COOKIE ECHO / ERROR exchange, and should add no 2556 * more than 1 second beyond the measured RTT, due to long 2557 * State Cookie lifetimes making the endpoint more subject to 2558 * a replay attack. 2559 * Measure of Staleness's unit is usec. (1/1000000 sec) 2560 * Suggested Cookie Life-span Increment's unit is msec. 2561 * (1/1000 sec) 2562 * In general, if you use the suggested cookie life, the value 2563 * found in the field of measure of staleness should be doubled 2564 * to give ample time to retransmit the new cookie and thus 2565 * yield a higher probability of success on the reattempt. 2566 */ 2567 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2568 stale = (stale * 2) / 1000; 2569 2570 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2571 bht.param_hdr.length = htons(sizeof(bht)); 2572 bht.lifespan_increment = htonl(stale); 2573 2574 /* Build that new INIT chunk. */ 2575 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2576 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2577 if (!reply) 2578 goto nomem; 2579 2580 sctp_addto_chunk(reply, sizeof(bht), &bht); 2581 2582 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2583 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2584 2585 /* Stop pending T3-rtx and heartbeat timers */ 2586 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2587 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2588 2589 /* Delete non-primary peer ip addresses since we are transitioning 2590 * back to the COOKIE-WAIT state 2591 */ 2592 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2593 2594 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2595 * resend 2596 */ 2597 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2598 SCTP_TRANSPORT(asoc->peer.primary_path)); 2599 2600 /* Cast away the const modifier, as we want to just 2601 * rerun it through as a sideffect. 2602 */ 2603 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2604 2605 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2606 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2607 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2608 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2609 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2610 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2611 2612 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2613 2614 return SCTP_DISPOSITION_CONSUME; 2615 2616 nomem: 2617 return SCTP_DISPOSITION_NOMEM; 2618 } 2619 2620 /* 2621 * Process an ABORT. 2622 * 2623 * Section: 9.1 2624 * After checking the Verification Tag, the receiving endpoint shall 2625 * remove the association from its record, and shall report the 2626 * termination to its upper layer. 2627 * 2628 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2629 * B) Rules for packet carrying ABORT: 2630 * 2631 * - The endpoint shall always fill in the Verification Tag field of the 2632 * outbound packet with the destination endpoint's tag value if it 2633 * is known. 2634 * 2635 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2636 * MUST follow the procedure described in Section 8.4. 2637 * 2638 * - The receiver MUST accept the packet if the Verification Tag 2639 * matches either its own tag, OR the tag of its peer. Otherwise, the 2640 * receiver MUST silently discard the packet and take no further 2641 * action. 2642 * 2643 * Inputs 2644 * (endpoint, asoc, chunk) 2645 * 2646 * Outputs 2647 * (asoc, reply_msg, msg_up, timers, counters) 2648 * 2649 * The return value is the disposition of the chunk. 2650 */ 2651 enum sctp_disposition sctp_sf_do_9_1_abort( 2652 struct net *net, 2653 const struct sctp_endpoint *ep, 2654 const struct sctp_association *asoc, 2655 const union sctp_subtype type, 2656 void *arg, 2657 struct sctp_cmd_seq *commands) 2658 { 2659 struct sctp_chunk *chunk = arg; 2660 2661 if (!sctp_vtag_verify_either(chunk, asoc)) 2662 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2663 2664 /* Make sure that the ABORT chunk has a valid length. 2665 * Since this is an ABORT chunk, we have to discard it 2666 * because of the following text: 2667 * RFC 2960, Section 3.3.7 2668 * If an endpoint receives an ABORT with a format error or for an 2669 * association that doesn't exist, it MUST silently discard it. 2670 * Because the length is "invalid", we can't really discard just 2671 * as we do not know its true length. So, to be safe, discard the 2672 * packet. 2673 */ 2674 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2676 2677 /* ADD-IP: Special case for ABORT chunks 2678 * F4) One special consideration is that ABORT Chunks arriving 2679 * destined to the IP address being deleted MUST be 2680 * ignored (see Section 5.3.1 for further details). 2681 */ 2682 if (SCTP_ADDR_DEL == 2683 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2684 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2685 2686 if (!sctp_err_chunk_valid(chunk)) 2687 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2688 2689 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2690 } 2691 2692 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2693 struct net *net, 2694 const struct sctp_endpoint *ep, 2695 const struct sctp_association *asoc, 2696 const union sctp_subtype type, 2697 void *arg, 2698 struct sctp_cmd_seq *commands) 2699 { 2700 __be16 error = SCTP_ERROR_NO_ERROR; 2701 struct sctp_chunk *chunk = arg; 2702 unsigned int len; 2703 2704 /* See if we have an error cause code in the chunk. */ 2705 len = ntohs(chunk->chunk_hdr->length); 2706 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2707 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2708 2709 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2710 /* ASSOC_FAILED will DELETE_TCB. */ 2711 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2712 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2713 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2714 2715 return SCTP_DISPOSITION_ABORT; 2716 } 2717 2718 /* 2719 * Process an ABORT. (COOKIE-WAIT state) 2720 * 2721 * See sctp_sf_do_9_1_abort() above. 2722 */ 2723 enum sctp_disposition sctp_sf_cookie_wait_abort( 2724 struct net *net, 2725 const struct sctp_endpoint *ep, 2726 const struct sctp_association *asoc, 2727 const union sctp_subtype type, 2728 void *arg, 2729 struct sctp_cmd_seq *commands) 2730 { 2731 __be16 error = SCTP_ERROR_NO_ERROR; 2732 struct sctp_chunk *chunk = arg; 2733 unsigned int len; 2734 2735 if (!sctp_vtag_verify_either(chunk, asoc)) 2736 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2737 2738 /* Make sure that the ABORT chunk has a valid length. 2739 * Since this is an ABORT chunk, we have to discard it 2740 * because of the following text: 2741 * RFC 2960, Section 3.3.7 2742 * If an endpoint receives an ABORT with a format error or for an 2743 * association that doesn't exist, it MUST silently discard it. 2744 * Because the length is "invalid", we can't really discard just 2745 * as we do not know its true length. So, to be safe, discard the 2746 * packet. 2747 */ 2748 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2749 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2750 2751 /* See if we have an error cause code in the chunk. */ 2752 len = ntohs(chunk->chunk_hdr->length); 2753 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2754 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2755 2756 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2757 chunk->transport); 2758 } 2759 2760 /* 2761 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2762 */ 2763 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2764 struct net *net, 2765 const struct sctp_endpoint *ep, 2766 const struct sctp_association *asoc, 2767 const union sctp_subtype type, 2768 void *arg, 2769 struct sctp_cmd_seq *commands) 2770 { 2771 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2772 ENOPROTOOPT, asoc, 2773 (struct sctp_transport *)arg); 2774 } 2775 2776 /* 2777 * Process an ABORT. (COOKIE-ECHOED state) 2778 */ 2779 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2780 struct net *net, 2781 const struct sctp_endpoint *ep, 2782 const struct sctp_association *asoc, 2783 const union sctp_subtype type, 2784 void *arg, 2785 struct sctp_cmd_seq *commands) 2786 { 2787 /* There is a single T1 timer, so we should be able to use 2788 * common function with the COOKIE-WAIT state. 2789 */ 2790 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2791 } 2792 2793 /* 2794 * Stop T1 timer and abort association with "INIT failed". 2795 * 2796 * This is common code called by several sctp_sf_*_abort() functions above. 2797 */ 2798 static enum sctp_disposition sctp_stop_t1_and_abort( 2799 struct net *net, 2800 struct sctp_cmd_seq *commands, 2801 __be16 error, int sk_err, 2802 const struct sctp_association *asoc, 2803 struct sctp_transport *transport) 2804 { 2805 pr_debug("%s: ABORT received (INIT)\n", __func__); 2806 2807 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2808 SCTP_STATE(SCTP_STATE_CLOSED)); 2809 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2810 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2811 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2812 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2813 /* CMD_INIT_FAILED will DELETE_TCB. */ 2814 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2815 SCTP_PERR(error)); 2816 2817 return SCTP_DISPOSITION_ABORT; 2818 } 2819 2820 /* 2821 * sctp_sf_do_9_2_shut 2822 * 2823 * Section: 9.2 2824 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2825 * - enter the SHUTDOWN-RECEIVED state, 2826 * 2827 * - stop accepting new data from its SCTP user 2828 * 2829 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2830 * that all its outstanding DATA chunks have been received by the 2831 * SHUTDOWN sender. 2832 * 2833 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2834 * send a SHUTDOWN in response to a ULP request. And should discard 2835 * subsequent SHUTDOWN chunks. 2836 * 2837 * If there are still outstanding DATA chunks left, the SHUTDOWN 2838 * receiver shall continue to follow normal data transmission 2839 * procedures defined in Section 6 until all outstanding DATA chunks 2840 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2841 * new data from its SCTP user. 2842 * 2843 * Verification Tag: 8.5 Verification Tag [Normal verification] 2844 * 2845 * Inputs 2846 * (endpoint, asoc, chunk) 2847 * 2848 * Outputs 2849 * (asoc, reply_msg, msg_up, timers, counters) 2850 * 2851 * The return value is the disposition of the chunk. 2852 */ 2853 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2854 struct net *net, 2855 const struct sctp_endpoint *ep, 2856 const struct sctp_association *asoc, 2857 const union sctp_subtype type, 2858 void *arg, 2859 struct sctp_cmd_seq *commands) 2860 { 2861 enum sctp_disposition disposition; 2862 struct sctp_chunk *chunk = arg; 2863 struct sctp_shutdownhdr *sdh; 2864 struct sctp_ulpevent *ev; 2865 __u32 ctsn; 2866 2867 if (!sctp_vtag_verify(chunk, asoc)) 2868 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2869 2870 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2871 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2872 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2873 commands); 2874 2875 /* Convert the elaborate header. */ 2876 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2877 skb_pull(chunk->skb, sizeof(*sdh)); 2878 chunk->subh.shutdown_hdr = sdh; 2879 ctsn = ntohl(sdh->cum_tsn_ack); 2880 2881 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2882 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2883 asoc->ctsn_ack_point); 2884 2885 return SCTP_DISPOSITION_DISCARD; 2886 } 2887 2888 /* If Cumulative TSN Ack beyond the max tsn currently 2889 * send, terminating the association and respond to the 2890 * sender with an ABORT. 2891 */ 2892 if (!TSN_lt(ctsn, asoc->next_tsn)) 2893 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2894 2895 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2896 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2897 * inform the application that it should cease sending data. 2898 */ 2899 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2900 if (!ev) { 2901 disposition = SCTP_DISPOSITION_NOMEM; 2902 goto out; 2903 } 2904 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2905 2906 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2907 * - enter the SHUTDOWN-RECEIVED state, 2908 * - stop accepting new data from its SCTP user 2909 * 2910 * [This is implicit in the new state.] 2911 */ 2912 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2913 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2914 disposition = SCTP_DISPOSITION_CONSUME; 2915 2916 if (sctp_outq_is_empty(&asoc->outqueue)) { 2917 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2918 arg, commands); 2919 } 2920 2921 if (SCTP_DISPOSITION_NOMEM == disposition) 2922 goto out; 2923 2924 /* - verify, by checking the Cumulative TSN Ack field of the 2925 * chunk, that all its outstanding DATA chunks have been 2926 * received by the SHUTDOWN sender. 2927 */ 2928 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2929 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2930 2931 out: 2932 return disposition; 2933 } 2934 2935 /* 2936 * sctp_sf_do_9_2_shut_ctsn 2937 * 2938 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2939 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2940 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2941 * MUST be processed. 2942 */ 2943 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2944 struct net *net, 2945 const struct sctp_endpoint *ep, 2946 const struct sctp_association *asoc, 2947 const union sctp_subtype type, 2948 void *arg, 2949 struct sctp_cmd_seq *commands) 2950 { 2951 struct sctp_chunk *chunk = arg; 2952 struct sctp_shutdownhdr *sdh; 2953 __u32 ctsn; 2954 2955 if (!sctp_vtag_verify(chunk, asoc)) 2956 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2957 2958 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2959 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2960 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2961 commands); 2962 2963 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2964 ctsn = ntohl(sdh->cum_tsn_ack); 2965 2966 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2967 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2968 asoc->ctsn_ack_point); 2969 2970 return SCTP_DISPOSITION_DISCARD; 2971 } 2972 2973 /* If Cumulative TSN Ack beyond the max tsn currently 2974 * send, terminating the association and respond to the 2975 * sender with an ABORT. 2976 */ 2977 if (!TSN_lt(ctsn, asoc->next_tsn)) 2978 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2979 2980 /* verify, by checking the Cumulative TSN Ack field of the 2981 * chunk, that all its outstanding DATA chunks have been 2982 * received by the SHUTDOWN sender. 2983 */ 2984 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2985 SCTP_BE32(sdh->cum_tsn_ack)); 2986 2987 return SCTP_DISPOSITION_CONSUME; 2988 } 2989 2990 /* RFC 2960 9.2 2991 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2992 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2993 * transport addresses (either in the IP addresses or in the INIT chunk) 2994 * that belong to this association, it should discard the INIT chunk and 2995 * retransmit the SHUTDOWN ACK chunk. 2996 */ 2997 static enum sctp_disposition 2998 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 2999 const struct sctp_association *asoc, 3000 const union sctp_subtype type, void *arg, 3001 struct sctp_cmd_seq *commands) 3002 { 3003 struct sctp_chunk *chunk = arg; 3004 struct sctp_chunk *reply; 3005 3006 /* Make sure that the chunk has a valid length */ 3007 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3008 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3009 commands); 3010 3011 /* Since we are not going to really process this INIT, there 3012 * is no point in verifying chunk boundaries. Just generate 3013 * the SHUTDOWN ACK. 3014 */ 3015 reply = sctp_make_shutdown_ack(asoc, chunk); 3016 if (NULL == reply) 3017 goto nomem; 3018 3019 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 3020 * the T2-SHUTDOWN timer. 3021 */ 3022 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 3023 3024 /* and restart the T2-shutdown timer. */ 3025 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3026 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3027 3028 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3029 3030 return SCTP_DISPOSITION_CONSUME; 3031 nomem: 3032 return SCTP_DISPOSITION_NOMEM; 3033 } 3034 3035 enum sctp_disposition 3036 sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3037 const struct sctp_association *asoc, 3038 const union sctp_subtype type, void *arg, 3039 struct sctp_cmd_seq *commands) 3040 { 3041 struct sctp_chunk *chunk = arg; 3042 3043 if (!chunk->singleton) 3044 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3045 3046 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 3047 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3048 3049 if (chunk->sctp_hdr->vtag != 0) 3050 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3051 3052 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands); 3053 } 3054 3055 /* 3056 * sctp_sf_do_ecn_cwr 3057 * 3058 * Section: Appendix A: Explicit Congestion Notification 3059 * 3060 * CWR: 3061 * 3062 * RFC 2481 details a specific bit for a sender to send in the header of 3063 * its next outbound TCP segment to indicate to its peer that it has 3064 * reduced its congestion window. This is termed the CWR bit. For 3065 * SCTP the same indication is made by including the CWR chunk. 3066 * This chunk contains one data element, i.e. the TSN number that 3067 * was sent in the ECNE chunk. This element represents the lowest 3068 * TSN number in the datagram that was originally marked with the 3069 * CE bit. 3070 * 3071 * Verification Tag: 8.5 Verification Tag [Normal verification] 3072 * Inputs 3073 * (endpoint, asoc, chunk) 3074 * 3075 * Outputs 3076 * (asoc, reply_msg, msg_up, timers, counters) 3077 * 3078 * The return value is the disposition of the chunk. 3079 */ 3080 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3081 const struct sctp_endpoint *ep, 3082 const struct sctp_association *asoc, 3083 const union sctp_subtype type, 3084 void *arg, 3085 struct sctp_cmd_seq *commands) 3086 { 3087 struct sctp_chunk *chunk = arg; 3088 struct sctp_cwrhdr *cwr; 3089 u32 lowest_tsn; 3090 3091 if (!sctp_vtag_verify(chunk, asoc)) 3092 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3093 3094 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3095 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3096 commands); 3097 3098 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3099 skb_pull(chunk->skb, sizeof(*cwr)); 3100 3101 lowest_tsn = ntohl(cwr->lowest_tsn); 3102 3103 /* Does this CWR ack the last sent congestion notification? */ 3104 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3105 /* Stop sending ECNE. */ 3106 sctp_add_cmd_sf(commands, 3107 SCTP_CMD_ECN_CWR, 3108 SCTP_U32(lowest_tsn)); 3109 } 3110 return SCTP_DISPOSITION_CONSUME; 3111 } 3112 3113 /* 3114 * sctp_sf_do_ecne 3115 * 3116 * Section: Appendix A: Explicit Congestion Notification 3117 * 3118 * ECN-Echo 3119 * 3120 * RFC 2481 details a specific bit for a receiver to send back in its 3121 * TCP acknowledgements to notify the sender of the Congestion 3122 * Experienced (CE) bit having arrived from the network. For SCTP this 3123 * same indication is made by including the ECNE chunk. This chunk 3124 * contains one data element, i.e. the lowest TSN associated with the IP 3125 * datagram marked with the CE bit..... 3126 * 3127 * Verification Tag: 8.5 Verification Tag [Normal verification] 3128 * Inputs 3129 * (endpoint, asoc, chunk) 3130 * 3131 * Outputs 3132 * (asoc, reply_msg, msg_up, timers, counters) 3133 * 3134 * The return value is the disposition of the chunk. 3135 */ 3136 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3137 const struct sctp_endpoint *ep, 3138 const struct sctp_association *asoc, 3139 const union sctp_subtype type, 3140 void *arg, struct sctp_cmd_seq *commands) 3141 { 3142 struct sctp_chunk *chunk = arg; 3143 struct sctp_ecnehdr *ecne; 3144 3145 if (!sctp_vtag_verify(chunk, asoc)) 3146 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3147 3148 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3149 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3150 commands); 3151 3152 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3153 skb_pull(chunk->skb, sizeof(*ecne)); 3154 3155 /* If this is a newer ECNE than the last CWR packet we sent out */ 3156 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3157 SCTP_U32(ntohl(ecne->lowest_tsn))); 3158 3159 return SCTP_DISPOSITION_CONSUME; 3160 } 3161 3162 /* 3163 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3164 * 3165 * The SCTP endpoint MUST always acknowledge the reception of each valid 3166 * DATA chunk. 3167 * 3168 * The guidelines on delayed acknowledgement algorithm specified in 3169 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3170 * acknowledgement SHOULD be generated for at least every second packet 3171 * (not every second DATA chunk) received, and SHOULD be generated within 3172 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3173 * situations it may be beneficial for an SCTP transmitter to be more 3174 * conservative than the algorithms detailed in this document allow. 3175 * However, an SCTP transmitter MUST NOT be more aggressive than the 3176 * following algorithms allow. 3177 * 3178 * A SCTP receiver MUST NOT generate more than one SACK for every 3179 * incoming packet, other than to update the offered window as the 3180 * receiving application consumes new data. 3181 * 3182 * Verification Tag: 8.5 Verification Tag [Normal verification] 3183 * 3184 * Inputs 3185 * (endpoint, asoc, chunk) 3186 * 3187 * Outputs 3188 * (asoc, reply_msg, msg_up, timers, counters) 3189 * 3190 * The return value is the disposition of the chunk. 3191 */ 3192 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3193 const struct sctp_endpoint *ep, 3194 const struct sctp_association *asoc, 3195 const union sctp_subtype type, 3196 void *arg, 3197 struct sctp_cmd_seq *commands) 3198 { 3199 union sctp_arg force = SCTP_NOFORCE(); 3200 struct sctp_chunk *chunk = arg; 3201 int error; 3202 3203 if (!sctp_vtag_verify(chunk, asoc)) { 3204 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3205 SCTP_NULL()); 3206 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3207 } 3208 3209 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3210 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3211 commands); 3212 3213 error = sctp_eat_data(asoc, chunk, commands); 3214 switch (error) { 3215 case SCTP_IERROR_NO_ERROR: 3216 break; 3217 case SCTP_IERROR_HIGH_TSN: 3218 case SCTP_IERROR_BAD_STREAM: 3219 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3220 goto discard_noforce; 3221 case SCTP_IERROR_DUP_TSN: 3222 case SCTP_IERROR_IGNORE_TSN: 3223 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3224 goto discard_force; 3225 case SCTP_IERROR_NO_DATA: 3226 return SCTP_DISPOSITION_ABORT; 3227 case SCTP_IERROR_PROTO_VIOLATION: 3228 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3229 (u8 *)chunk->subh.data_hdr, 3230 sctp_datahdr_len(&asoc->stream)); 3231 default: 3232 BUG(); 3233 } 3234 3235 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3236 force = SCTP_FORCE(); 3237 3238 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3239 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3240 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3241 } 3242 3243 /* If this is the last chunk in a packet, we need to count it 3244 * toward sack generation. Note that we need to SACK every 3245 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3246 * THEM. We elect to NOT generate SACK's if the chunk fails 3247 * the verification tag test. 3248 * 3249 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3250 * 3251 * The SCTP endpoint MUST always acknowledge the reception of 3252 * each valid DATA chunk. 3253 * 3254 * The guidelines on delayed acknowledgement algorithm 3255 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3256 * Specifically, an acknowledgement SHOULD be generated for at 3257 * least every second packet (not every second DATA chunk) 3258 * received, and SHOULD be generated within 200 ms of the 3259 * arrival of any unacknowledged DATA chunk. In some 3260 * situations it may be beneficial for an SCTP transmitter to 3261 * be more conservative than the algorithms detailed in this 3262 * document allow. However, an SCTP transmitter MUST NOT be 3263 * more aggressive than the following algorithms allow. 3264 */ 3265 if (chunk->end_of_packet) 3266 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3267 3268 return SCTP_DISPOSITION_CONSUME; 3269 3270 discard_force: 3271 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3272 * 3273 * When a packet arrives with duplicate DATA chunk(s) and with 3274 * no new DATA chunk(s), the endpoint MUST immediately send a 3275 * SACK with no delay. If a packet arrives with duplicate 3276 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3277 * MAY immediately send a SACK. Normally receipt of duplicate 3278 * DATA chunks will occur when the original SACK chunk was lost 3279 * and the peer's RTO has expired. The duplicate TSN number(s) 3280 * SHOULD be reported in the SACK as duplicate. 3281 */ 3282 /* In our case, we split the MAY SACK advice up whether or not 3283 * the last chunk is a duplicate.' 3284 */ 3285 if (chunk->end_of_packet) 3286 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3287 return SCTP_DISPOSITION_DISCARD; 3288 3289 discard_noforce: 3290 if (chunk->end_of_packet) 3291 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3292 3293 return SCTP_DISPOSITION_DISCARD; 3294 } 3295 3296 /* 3297 * sctp_sf_eat_data_fast_4_4 3298 * 3299 * Section: 4 (4) 3300 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3301 * DATA chunks without delay. 3302 * 3303 * Verification Tag: 8.5 Verification Tag [Normal verification] 3304 * Inputs 3305 * (endpoint, asoc, chunk) 3306 * 3307 * Outputs 3308 * (asoc, reply_msg, msg_up, timers, counters) 3309 * 3310 * The return value is the disposition of the chunk. 3311 */ 3312 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3313 struct net *net, 3314 const struct sctp_endpoint *ep, 3315 const struct sctp_association *asoc, 3316 const union sctp_subtype type, 3317 void *arg, 3318 struct sctp_cmd_seq *commands) 3319 { 3320 struct sctp_chunk *chunk = arg; 3321 int error; 3322 3323 if (!sctp_vtag_verify(chunk, asoc)) { 3324 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3325 SCTP_NULL()); 3326 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3327 } 3328 3329 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3330 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3331 commands); 3332 3333 error = sctp_eat_data(asoc, chunk, commands); 3334 switch (error) { 3335 case SCTP_IERROR_NO_ERROR: 3336 case SCTP_IERROR_HIGH_TSN: 3337 case SCTP_IERROR_DUP_TSN: 3338 case SCTP_IERROR_IGNORE_TSN: 3339 case SCTP_IERROR_BAD_STREAM: 3340 break; 3341 case SCTP_IERROR_NO_DATA: 3342 return SCTP_DISPOSITION_ABORT; 3343 case SCTP_IERROR_PROTO_VIOLATION: 3344 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3345 (u8 *)chunk->subh.data_hdr, 3346 sctp_datahdr_len(&asoc->stream)); 3347 default: 3348 BUG(); 3349 } 3350 3351 /* Go a head and force a SACK, since we are shutting down. */ 3352 3353 /* Implementor's Guide. 3354 * 3355 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3356 * respond to each received packet containing one or more DATA chunk(s) 3357 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3358 */ 3359 if (chunk->end_of_packet) { 3360 /* We must delay the chunk creation since the cumulative 3361 * TSN has not been updated yet. 3362 */ 3363 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3364 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3365 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3366 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3367 } 3368 3369 return SCTP_DISPOSITION_CONSUME; 3370 } 3371 3372 /* 3373 * Section: 6.2 Processing a Received SACK 3374 * D) Any time a SACK arrives, the endpoint performs the following: 3375 * 3376 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3377 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3378 * increasing, a SACK whose Cumulative TSN Ack is less than the 3379 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3380 * 3381 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3382 * of bytes still outstanding after processing the Cumulative TSN Ack 3383 * and the Gap Ack Blocks. 3384 * 3385 * iii) If the SACK is missing a TSN that was previously 3386 * acknowledged via a Gap Ack Block (e.g., the data receiver 3387 * reneged on the data), then mark the corresponding DATA chunk 3388 * as available for retransmit: Mark it as missing for fast 3389 * retransmit as described in Section 7.2.4 and if no retransmit 3390 * timer is running for the destination address to which the DATA 3391 * chunk was originally transmitted, then T3-rtx is started for 3392 * that destination address. 3393 * 3394 * Verification Tag: 8.5 Verification Tag [Normal verification] 3395 * 3396 * Inputs 3397 * (endpoint, asoc, chunk) 3398 * 3399 * Outputs 3400 * (asoc, reply_msg, msg_up, timers, counters) 3401 * 3402 * The return value is the disposition of the chunk. 3403 */ 3404 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3405 const struct sctp_endpoint *ep, 3406 const struct sctp_association *asoc, 3407 const union sctp_subtype type, 3408 void *arg, 3409 struct sctp_cmd_seq *commands) 3410 { 3411 struct sctp_chunk *chunk = arg; 3412 struct sctp_sackhdr *sackh; 3413 __u32 ctsn; 3414 3415 if (!sctp_vtag_verify(chunk, asoc)) 3416 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3417 3418 /* Make sure that the SACK chunk has a valid length. */ 3419 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3420 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3421 commands); 3422 3423 /* Pull the SACK chunk from the data buffer */ 3424 sackh = sctp_sm_pull_sack(chunk); 3425 /* Was this a bogus SACK? */ 3426 if (!sackh) 3427 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3428 chunk->subh.sack_hdr = sackh; 3429 ctsn = ntohl(sackh->cum_tsn_ack); 3430 3431 /* If Cumulative TSN Ack beyond the max tsn currently 3432 * send, terminating the association and respond to the 3433 * sender with an ABORT. 3434 */ 3435 if (TSN_lte(asoc->next_tsn, ctsn)) 3436 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3437 3438 trace_sctp_probe(ep, asoc, chunk); 3439 3440 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3441 * Ack Point, then drop the SACK. Since Cumulative TSN 3442 * Ack is monotonically increasing, a SACK whose 3443 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3444 * Point indicates an out-of-order SACK. 3445 */ 3446 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3447 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3448 asoc->ctsn_ack_point); 3449 3450 return SCTP_DISPOSITION_DISCARD; 3451 } 3452 3453 /* Return this SACK for further processing. */ 3454 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3455 3456 /* Note: We do the rest of the work on the PROCESS_SACK 3457 * sideeffect. 3458 */ 3459 return SCTP_DISPOSITION_CONSUME; 3460 } 3461 3462 /* 3463 * Generate an ABORT in response to a packet. 3464 * 3465 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3466 * 3467 * 8) The receiver should respond to the sender of the OOTB packet with 3468 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3469 * MUST fill in the Verification Tag field of the outbound packet 3470 * with the value found in the Verification Tag field of the OOTB 3471 * packet and set the T-bit in the Chunk Flags to indicate that the 3472 * Verification Tag is reflected. After sending this ABORT, the 3473 * receiver of the OOTB packet shall discard the OOTB packet and take 3474 * no further action. 3475 * 3476 * Verification Tag: 3477 * 3478 * The return value is the disposition of the chunk. 3479 */ 3480 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3481 struct net *net, 3482 const struct sctp_endpoint *ep, 3483 const struct sctp_association *asoc, 3484 const union sctp_subtype type, 3485 void *arg, 3486 struct sctp_cmd_seq *commands) 3487 { 3488 struct sctp_packet *packet = NULL; 3489 struct sctp_chunk *chunk = arg; 3490 struct sctp_chunk *abort; 3491 3492 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3493 if (!packet) 3494 return SCTP_DISPOSITION_NOMEM; 3495 3496 /* Make an ABORT. The T bit will be set if the asoc 3497 * is NULL. 3498 */ 3499 abort = sctp_make_abort(asoc, chunk, 0); 3500 if (!abort) { 3501 sctp_ootb_pkt_free(packet); 3502 return SCTP_DISPOSITION_NOMEM; 3503 } 3504 3505 /* Reflect vtag if T-Bit is set */ 3506 if (sctp_test_T_bit(abort)) 3507 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3508 3509 /* Set the skb to the belonging sock for accounting. */ 3510 abort->skb->sk = ep->base.sk; 3511 3512 sctp_packet_append_chunk(packet, abort); 3513 3514 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3515 3516 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3517 3518 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3519 return SCTP_DISPOSITION_CONSUME; 3520 } 3521 3522 /* Handling of SCTP Packets Containing an INIT Chunk Matching an 3523 * Existing Associations when the UDP encap port is incorrect. 3524 * 3525 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3526 */ 3527 static enum sctp_disposition sctp_sf_new_encap_port( 3528 struct net *net, 3529 const struct sctp_endpoint *ep, 3530 const struct sctp_association *asoc, 3531 const union sctp_subtype type, 3532 void *arg, 3533 struct sctp_cmd_seq *commands) 3534 { 3535 struct sctp_packet *packet = NULL; 3536 struct sctp_chunk *chunk = arg; 3537 struct sctp_chunk *abort; 3538 3539 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3540 if (!packet) 3541 return SCTP_DISPOSITION_NOMEM; 3542 3543 abort = sctp_make_new_encap_port(asoc, chunk); 3544 if (!abort) { 3545 sctp_ootb_pkt_free(packet); 3546 return SCTP_DISPOSITION_NOMEM; 3547 } 3548 3549 abort->skb->sk = ep->base.sk; 3550 3551 sctp_packet_append_chunk(packet, abort); 3552 3553 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3554 SCTP_PACKET(packet)); 3555 3556 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3557 3558 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3559 return SCTP_DISPOSITION_CONSUME; 3560 } 3561 3562 /* 3563 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3564 * event as ULP notification for each cause included in the chunk. 3565 * 3566 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3567 * 3568 * The return value is the disposition of the chunk. 3569 */ 3570 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3571 const struct sctp_endpoint *ep, 3572 const struct sctp_association *asoc, 3573 const union sctp_subtype type, 3574 void *arg, 3575 struct sctp_cmd_seq *commands) 3576 { 3577 struct sctp_chunk *chunk = arg; 3578 struct sctp_errhdr *err; 3579 3580 if (!sctp_vtag_verify(chunk, asoc)) 3581 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3582 3583 /* Make sure that the ERROR chunk has a valid length. */ 3584 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3585 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3586 commands); 3587 sctp_walk_errors(err, chunk->chunk_hdr); 3588 if ((void *)err != (void *)chunk->chunk_end) 3589 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3590 (void *)err, commands); 3591 3592 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3593 SCTP_CHUNK(chunk)); 3594 3595 return SCTP_DISPOSITION_CONSUME; 3596 } 3597 3598 /* 3599 * Process an inbound SHUTDOWN ACK. 3600 * 3601 * From Section 9.2: 3602 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3603 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3604 * peer, and remove all record of the association. 3605 * 3606 * The return value is the disposition. 3607 */ 3608 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3609 const struct sctp_endpoint *ep, 3610 const struct sctp_association *asoc, 3611 const union sctp_subtype type, 3612 void *arg, 3613 struct sctp_cmd_seq *commands) 3614 { 3615 struct sctp_chunk *chunk = arg; 3616 struct sctp_chunk *reply; 3617 struct sctp_ulpevent *ev; 3618 3619 if (!sctp_vtag_verify(chunk, asoc)) 3620 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3621 3622 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3623 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3624 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3625 commands); 3626 /* 10.2 H) SHUTDOWN COMPLETE notification 3627 * 3628 * When SCTP completes the shutdown procedures (section 9.2) this 3629 * notification is passed to the upper layer. 3630 */ 3631 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3632 0, 0, 0, NULL, GFP_ATOMIC); 3633 if (!ev) 3634 goto nomem; 3635 3636 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3637 reply = sctp_make_shutdown_complete(asoc, chunk); 3638 if (!reply) 3639 goto nomem_chunk; 3640 3641 /* Do all the commands now (after allocation), so that we 3642 * have consistent state if memory allocation fails 3643 */ 3644 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3645 3646 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3647 * stop the T2-shutdown timer, 3648 */ 3649 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3650 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3651 3652 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3653 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3654 3655 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3656 SCTP_STATE(SCTP_STATE_CLOSED)); 3657 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3658 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3659 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3660 3661 /* ...and remove all record of the association. */ 3662 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3663 return SCTP_DISPOSITION_DELETE_TCB; 3664 3665 nomem_chunk: 3666 sctp_ulpevent_free(ev); 3667 nomem: 3668 return SCTP_DISPOSITION_NOMEM; 3669 } 3670 3671 /* 3672 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3673 * 3674 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3675 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3676 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3677 * packet must fill in the Verification Tag field of the outbound 3678 * packet with the Verification Tag received in the SHUTDOWN ACK and 3679 * set the T-bit in the Chunk Flags to indicate that the Verification 3680 * Tag is reflected. 3681 * 3682 * 8) The receiver should respond to the sender of the OOTB packet with 3683 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3684 * MUST fill in the Verification Tag field of the outbound packet 3685 * with the value found in the Verification Tag field of the OOTB 3686 * packet and set the T-bit in the Chunk Flags to indicate that the 3687 * Verification Tag is reflected. After sending this ABORT, the 3688 * receiver of the OOTB packet shall discard the OOTB packet and take 3689 * no further action. 3690 */ 3691 enum sctp_disposition sctp_sf_ootb(struct net *net, 3692 const struct sctp_endpoint *ep, 3693 const struct sctp_association *asoc, 3694 const union sctp_subtype type, 3695 void *arg, struct sctp_cmd_seq *commands) 3696 { 3697 struct sctp_chunk *chunk = arg; 3698 struct sk_buff *skb = chunk->skb; 3699 struct sctp_chunkhdr *ch; 3700 struct sctp_errhdr *err; 3701 int ootb_cookie_ack = 0; 3702 int ootb_shut_ack = 0; 3703 __u8 *ch_end; 3704 3705 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3706 3707 if (asoc && !sctp_vtag_verify(chunk, asoc)) 3708 asoc = NULL; 3709 3710 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3711 do { 3712 /* Report violation if the chunk is less then minimal */ 3713 if (ntohs(ch->length) < sizeof(*ch)) 3714 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3715 commands); 3716 3717 /* Report violation if chunk len overflows */ 3718 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3719 if (ch_end > skb_tail_pointer(skb)) 3720 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3721 commands); 3722 3723 /* Now that we know we at least have a chunk header, 3724 * do things that are type appropriate. 3725 */ 3726 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3727 ootb_shut_ack = 1; 3728 3729 /* RFC 2960, Section 3.3.7 3730 * Moreover, under any circumstances, an endpoint that 3731 * receives an ABORT MUST NOT respond to that ABORT by 3732 * sending an ABORT of its own. 3733 */ 3734 if (SCTP_CID_ABORT == ch->type) 3735 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3736 3737 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3738 * or a COOKIE ACK the SCTP Packet should be silently 3739 * discarded. 3740 */ 3741 3742 if (SCTP_CID_COOKIE_ACK == ch->type) 3743 ootb_cookie_ack = 1; 3744 3745 if (SCTP_CID_ERROR == ch->type) { 3746 sctp_walk_errors(err, ch) { 3747 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3748 ootb_cookie_ack = 1; 3749 break; 3750 } 3751 } 3752 } 3753 3754 ch = (struct sctp_chunkhdr *)ch_end; 3755 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); 3756 3757 if (ootb_shut_ack) 3758 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3759 else if (ootb_cookie_ack) 3760 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3761 else 3762 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3763 } 3764 3765 /* 3766 * Handle an "Out of the blue" SHUTDOWN ACK. 3767 * 3768 * Section: 8.4 5, sctpimpguide 2.41. 3769 * 3770 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3771 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3772 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3773 * packet must fill in the Verification Tag field of the outbound 3774 * packet with the Verification Tag received in the SHUTDOWN ACK and 3775 * set the T-bit in the Chunk Flags to indicate that the Verification 3776 * Tag is reflected. 3777 * 3778 * Inputs 3779 * (endpoint, asoc, type, arg, commands) 3780 * 3781 * Outputs 3782 * (enum sctp_disposition) 3783 * 3784 * The return value is the disposition of the chunk. 3785 */ 3786 static enum sctp_disposition sctp_sf_shut_8_4_5( 3787 struct net *net, 3788 const struct sctp_endpoint *ep, 3789 const struct sctp_association *asoc, 3790 const union sctp_subtype type, 3791 void *arg, 3792 struct sctp_cmd_seq *commands) 3793 { 3794 struct sctp_packet *packet = NULL; 3795 struct sctp_chunk *chunk = arg; 3796 struct sctp_chunk *shut; 3797 3798 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3799 if (!packet) 3800 return SCTP_DISPOSITION_NOMEM; 3801 3802 /* Make an SHUTDOWN_COMPLETE. 3803 * The T bit will be set if the asoc is NULL. 3804 */ 3805 shut = sctp_make_shutdown_complete(asoc, chunk); 3806 if (!shut) { 3807 sctp_ootb_pkt_free(packet); 3808 return SCTP_DISPOSITION_NOMEM; 3809 } 3810 3811 /* Reflect vtag if T-Bit is set */ 3812 if (sctp_test_T_bit(shut)) 3813 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3814 3815 /* Set the skb to the belonging sock for accounting. */ 3816 shut->skb->sk = ep->base.sk; 3817 3818 sctp_packet_append_chunk(packet, shut); 3819 3820 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3821 SCTP_PACKET(packet)); 3822 3823 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3824 3825 /* We need to discard the rest of the packet to prevent 3826 * potential boomming attacks from additional bundled chunks. 3827 * This is documented in SCTP Threats ID. 3828 */ 3829 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3830 } 3831 3832 /* 3833 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3834 * 3835 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3836 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3837 * procedures in section 8.4 SHOULD be followed, in other words it 3838 * should be treated as an Out Of The Blue packet. 3839 * [This means that we do NOT check the Verification Tag on these 3840 * chunks. --piggy ] 3841 * 3842 */ 3843 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3844 const struct sctp_endpoint *ep, 3845 const struct sctp_association *asoc, 3846 const union sctp_subtype type, 3847 void *arg, 3848 struct sctp_cmd_seq *commands) 3849 { 3850 struct sctp_chunk *chunk = arg; 3851 3852 if (!sctp_vtag_verify(chunk, asoc)) 3853 asoc = NULL; 3854 3855 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3856 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3857 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3858 commands); 3859 3860 /* Although we do have an association in this case, it corresponds 3861 * to a restarted association. So the packet is treated as an OOTB 3862 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3863 * called with a NULL association. 3864 */ 3865 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3866 3867 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3868 } 3869 3870 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3871 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3872 const struct sctp_endpoint *ep, 3873 const struct sctp_association *asoc, 3874 const union sctp_subtype type, 3875 void *arg, 3876 struct sctp_cmd_seq *commands) 3877 { 3878 struct sctp_paramhdr *err_param = NULL; 3879 struct sctp_chunk *asconf_ack = NULL; 3880 struct sctp_chunk *chunk = arg; 3881 struct sctp_addiphdr *hdr; 3882 __u32 serial; 3883 3884 if (!sctp_vtag_verify(chunk, asoc)) { 3885 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3886 SCTP_NULL()); 3887 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3888 } 3889 3890 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3891 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3892 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3893 commands); 3894 3895 /* ADD-IP: Section 4.1.1 3896 * This chunk MUST be sent in an authenticated way by using 3897 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3898 * is received unauthenticated it MUST be silently discarded as 3899 * described in [I-D.ietf-tsvwg-sctp-auth]. 3900 */ 3901 if (!asoc->peer.asconf_capable || 3902 (!net->sctp.addip_noauth && !chunk->auth)) 3903 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3904 3905 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3906 serial = ntohl(hdr->serial); 3907 3908 /* Verify the ASCONF chunk before processing it. */ 3909 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3910 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3911 (void *)err_param, commands); 3912 3913 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3914 * the endpoint stored in a new association variable 3915 * 'Peer-Serial-Number'. 3916 */ 3917 if (serial == asoc->peer.addip_serial + 1) { 3918 /* If this is the first instance of ASCONF in the packet, 3919 * we can clean our old ASCONF-ACKs. 3920 */ 3921 if (!chunk->has_asconf) 3922 sctp_assoc_clean_asconf_ack_cache(asoc); 3923 3924 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3925 * expected, process the ASCONF as described below and after 3926 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3927 * the response packet and cache a copy of it (in the event it 3928 * later needs to be retransmitted). 3929 * 3930 * Essentially, do V1-V5. 3931 */ 3932 asconf_ack = sctp_process_asconf((struct sctp_association *) 3933 asoc, chunk); 3934 if (!asconf_ack) 3935 return SCTP_DISPOSITION_NOMEM; 3936 } else if (serial < asoc->peer.addip_serial + 1) { 3937 /* ADDIP 5.2 E2) 3938 * If the value found in the Sequence Number is less than the 3939 * ('Peer- Sequence-Number' + 1), simply skip to the next 3940 * ASCONF, and include in the outbound response packet 3941 * any previously cached ASCONF-ACK response that was 3942 * sent and saved that matches the Sequence Number of the 3943 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3944 * Chunk exists. This will occur when an older ASCONF 3945 * arrives out of order. In such a case, the receiver 3946 * should skip the ASCONF Chunk and not include ASCONF-ACK 3947 * Chunk for that chunk. 3948 */ 3949 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3950 if (!asconf_ack) 3951 return SCTP_DISPOSITION_DISCARD; 3952 3953 /* Reset the transport so that we select the correct one 3954 * this time around. This is to make sure that we don't 3955 * accidentally use a stale transport that's been removed. 3956 */ 3957 asconf_ack->transport = NULL; 3958 } else { 3959 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3960 * it must be either a stale packet or from an attacker. 3961 */ 3962 return SCTP_DISPOSITION_DISCARD; 3963 } 3964 3965 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3966 * containing the ASCONF-ACK Chunks MUST be the source address of 3967 * the SCTP packet that held the ASCONF Chunks. 3968 * 3969 * To do this properly, we'll set the destination address of the chunk 3970 * and at the transmit time, will try look up the transport to use. 3971 * Since ASCONFs may be bundled, the correct transport may not be 3972 * created until we process the entire packet, thus this workaround. 3973 */ 3974 asconf_ack->dest = chunk->source; 3975 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3976 if (asoc->new_transport) { 3977 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3978 ((struct sctp_association *)asoc)->new_transport = NULL; 3979 } 3980 3981 return SCTP_DISPOSITION_CONSUME; 3982 } 3983 3984 static enum sctp_disposition sctp_send_next_asconf( 3985 struct net *net, 3986 const struct sctp_endpoint *ep, 3987 struct sctp_association *asoc, 3988 const union sctp_subtype type, 3989 struct sctp_cmd_seq *commands) 3990 { 3991 struct sctp_chunk *asconf; 3992 struct list_head *entry; 3993 3994 if (list_empty(&asoc->addip_chunk_list)) 3995 return SCTP_DISPOSITION_CONSUME; 3996 3997 entry = asoc->addip_chunk_list.next; 3998 asconf = list_entry(entry, struct sctp_chunk, list); 3999 4000 list_del_init(entry); 4001 sctp_chunk_hold(asconf); 4002 asoc->addip_last_asconf = asconf; 4003 4004 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 4005 } 4006 4007 /* 4008 * ADDIP Section 4.3 General rules for address manipulation 4009 * When building TLV parameters for the ASCONF Chunk that will add or 4010 * delete IP addresses the D0 to D13 rules should be applied: 4011 */ 4012 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 4013 const struct sctp_endpoint *ep, 4014 const struct sctp_association *asoc, 4015 const union sctp_subtype type, 4016 void *arg, 4017 struct sctp_cmd_seq *commands) 4018 { 4019 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 4020 struct sctp_paramhdr *err_param = NULL; 4021 struct sctp_chunk *asconf_ack = arg; 4022 struct sctp_addiphdr *addip_hdr; 4023 __u32 sent_serial, rcvd_serial; 4024 struct sctp_chunk *abort; 4025 4026 if (!sctp_vtag_verify(asconf_ack, asoc)) { 4027 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4028 SCTP_NULL()); 4029 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4030 } 4031 4032 /* Make sure that the ADDIP chunk has a valid length. */ 4033 if (!sctp_chunk_length_valid(asconf_ack, 4034 sizeof(struct sctp_addip_chunk))) 4035 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4036 commands); 4037 4038 /* ADD-IP, Section 4.1.2: 4039 * This chunk MUST be sent in an authenticated way by using 4040 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 4041 * is received unauthenticated it MUST be silently discarded as 4042 * described in [I-D.ietf-tsvwg-sctp-auth]. 4043 */ 4044 if (!asoc->peer.asconf_capable || 4045 (!net->sctp.addip_noauth && !asconf_ack->auth)) 4046 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4047 4048 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 4049 rcvd_serial = ntohl(addip_hdr->serial); 4050 4051 /* Verify the ASCONF-ACK chunk before processing it. */ 4052 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 4053 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4054 (void *)err_param, commands); 4055 4056 if (last_asconf) { 4057 addip_hdr = last_asconf->subh.addip_hdr; 4058 sent_serial = ntohl(addip_hdr->serial); 4059 } else { 4060 sent_serial = asoc->addip_serial - 1; 4061 } 4062 4063 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 4064 * equal to the next serial number to be used but no ASCONF chunk is 4065 * outstanding the endpoint MUST ABORT the association. Note that a 4066 * sequence number is greater than if it is no more than 2^^31-1 4067 * larger than the current sequence number (using serial arithmetic). 4068 */ 4069 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 4070 !(asoc->addip_last_asconf)) { 4071 abort = sctp_make_abort(asoc, asconf_ack, 4072 sizeof(struct sctp_errhdr)); 4073 if (abort) { 4074 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 4075 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4076 SCTP_CHUNK(abort)); 4077 } 4078 /* We are going to ABORT, so we might as well stop 4079 * processing the rest of the chunks in the packet. 4080 */ 4081 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4082 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4083 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4084 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4085 SCTP_ERROR(ECONNABORTED)); 4086 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4087 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4088 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4089 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4090 return SCTP_DISPOSITION_ABORT; 4091 } 4092 4093 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4094 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4095 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4096 4097 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4098 asconf_ack)) 4099 return sctp_send_next_asconf(net, ep, 4100 (struct sctp_association *)asoc, 4101 type, commands); 4102 4103 abort = sctp_make_abort(asoc, asconf_ack, 4104 sizeof(struct sctp_errhdr)); 4105 if (abort) { 4106 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4107 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4108 SCTP_CHUNK(abort)); 4109 } 4110 /* We are going to ABORT, so we might as well stop 4111 * processing the rest of the chunks in the packet. 4112 */ 4113 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4114 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4115 SCTP_ERROR(ECONNABORTED)); 4116 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4117 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4118 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4119 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4120 return SCTP_DISPOSITION_ABORT; 4121 } 4122 4123 return SCTP_DISPOSITION_DISCARD; 4124 } 4125 4126 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4127 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4128 const struct sctp_endpoint *ep, 4129 const struct sctp_association *asoc, 4130 const union sctp_subtype type, 4131 void *arg, 4132 struct sctp_cmd_seq *commands) 4133 { 4134 struct sctp_paramhdr *err_param = NULL; 4135 struct sctp_chunk *chunk = arg; 4136 struct sctp_reconf_chunk *hdr; 4137 union sctp_params param; 4138 4139 if (!sctp_vtag_verify(chunk, asoc)) { 4140 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4141 SCTP_NULL()); 4142 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4143 } 4144 4145 /* Make sure that the RECONF chunk has a valid length. */ 4146 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4147 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4148 commands); 4149 4150 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4151 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4152 (void *)err_param, commands); 4153 4154 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4155 sctp_walk_params(param, hdr) { 4156 struct sctp_chunk *reply = NULL; 4157 struct sctp_ulpevent *ev = NULL; 4158 4159 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4160 reply = sctp_process_strreset_outreq( 4161 (struct sctp_association *)asoc, param, &ev); 4162 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4163 reply = sctp_process_strreset_inreq( 4164 (struct sctp_association *)asoc, param, &ev); 4165 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4166 reply = sctp_process_strreset_tsnreq( 4167 (struct sctp_association *)asoc, param, &ev); 4168 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4169 reply = sctp_process_strreset_addstrm_out( 4170 (struct sctp_association *)asoc, param, &ev); 4171 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4172 reply = sctp_process_strreset_addstrm_in( 4173 (struct sctp_association *)asoc, param, &ev); 4174 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4175 reply = sctp_process_strreset_resp( 4176 (struct sctp_association *)asoc, param, &ev); 4177 4178 if (ev) 4179 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4180 SCTP_ULPEVENT(ev)); 4181 4182 if (reply) 4183 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4184 SCTP_CHUNK(reply)); 4185 } 4186 4187 return SCTP_DISPOSITION_CONSUME; 4188 } 4189 4190 /* 4191 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4192 * 4193 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4194 * its cumulative TSN point to the value carried in the FORWARD TSN 4195 * chunk, and then MUST further advance its cumulative TSN point locally 4196 * if possible. 4197 * After the above processing, the data receiver MUST stop reporting any 4198 * missing TSNs earlier than or equal to the new cumulative TSN point. 4199 * 4200 * Verification Tag: 8.5 Verification Tag [Normal verification] 4201 * 4202 * The return value is the disposition of the chunk. 4203 */ 4204 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4205 const struct sctp_endpoint *ep, 4206 const struct sctp_association *asoc, 4207 const union sctp_subtype type, 4208 void *arg, 4209 struct sctp_cmd_seq *commands) 4210 { 4211 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4212 struct sctp_chunk *chunk = arg; 4213 __u16 len; 4214 __u32 tsn; 4215 4216 if (!sctp_vtag_verify(chunk, asoc)) { 4217 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4218 SCTP_NULL()); 4219 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4220 } 4221 4222 if (!asoc->peer.prsctp_capable) 4223 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4224 4225 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4226 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4227 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4228 commands); 4229 4230 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4231 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4232 len = ntohs(chunk->chunk_hdr->length); 4233 len -= sizeof(struct sctp_chunkhdr); 4234 skb_pull(chunk->skb, len); 4235 4236 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4237 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4238 4239 /* The TSN is too high--silently discard the chunk and count on it 4240 * getting retransmitted later. 4241 */ 4242 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4243 goto discard_noforce; 4244 4245 if (!asoc->stream.si->validate_ftsn(chunk)) 4246 goto discard_noforce; 4247 4248 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4249 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4250 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4251 SCTP_CHUNK(chunk)); 4252 4253 /* Count this as receiving DATA. */ 4254 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4255 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4256 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4257 } 4258 4259 /* FIXME: For now send a SACK, but DATA processing may 4260 * send another. 4261 */ 4262 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4263 4264 return SCTP_DISPOSITION_CONSUME; 4265 4266 discard_noforce: 4267 return SCTP_DISPOSITION_DISCARD; 4268 } 4269 4270 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4271 struct net *net, 4272 const struct sctp_endpoint *ep, 4273 const struct sctp_association *asoc, 4274 const union sctp_subtype type, 4275 void *arg, 4276 struct sctp_cmd_seq *commands) 4277 { 4278 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4279 struct sctp_chunk *chunk = arg; 4280 __u16 len; 4281 __u32 tsn; 4282 4283 if (!sctp_vtag_verify(chunk, asoc)) { 4284 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4285 SCTP_NULL()); 4286 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4287 } 4288 4289 if (!asoc->peer.prsctp_capable) 4290 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4291 4292 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4293 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4294 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4295 commands); 4296 4297 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4298 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4299 len = ntohs(chunk->chunk_hdr->length); 4300 len -= sizeof(struct sctp_chunkhdr); 4301 skb_pull(chunk->skb, len); 4302 4303 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4304 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4305 4306 /* The TSN is too high--silently discard the chunk and count on it 4307 * getting retransmitted later. 4308 */ 4309 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4310 goto gen_shutdown; 4311 4312 if (!asoc->stream.si->validate_ftsn(chunk)) 4313 goto gen_shutdown; 4314 4315 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4316 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4317 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4318 SCTP_CHUNK(chunk)); 4319 4320 /* Go a head and force a SACK, since we are shutting down. */ 4321 gen_shutdown: 4322 /* Implementor's Guide. 4323 * 4324 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4325 * respond to each received packet containing one or more DATA chunk(s) 4326 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4327 */ 4328 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4329 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4330 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4331 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4332 4333 return SCTP_DISPOSITION_CONSUME; 4334 } 4335 4336 /* 4337 * SCTP-AUTH Section 6.3 Receiving authenticated chunks 4338 * 4339 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4340 * Identifier field. If this algorithm was not specified by the 4341 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4342 * during association setup, the AUTH chunk and all chunks after it MUST 4343 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4344 * defined in Section 4.1. 4345 * 4346 * If an endpoint with no shared key receives a Shared Key Identifier 4347 * other than 0, it MUST silently discard all authenticated chunks. If 4348 * the endpoint has at least one endpoint pair shared key for the peer, 4349 * it MUST use the key specified by the Shared Key Identifier if a 4350 * key has been configured for that Shared Key Identifier. If no 4351 * endpoint pair shared key has been configured for that Shared Key 4352 * Identifier, all authenticated chunks MUST be silently discarded. 4353 * 4354 * Verification Tag: 8.5 Verification Tag [Normal verification] 4355 * 4356 * The return value is the disposition of the chunk. 4357 */ 4358 static enum sctp_ierror sctp_sf_authenticate( 4359 const struct sctp_association *asoc, 4360 struct sctp_chunk *chunk) 4361 { 4362 struct sctp_shared_key *sh_key = NULL; 4363 struct sctp_authhdr *auth_hdr; 4364 __u8 *save_digest, *digest; 4365 const struct sctp_hmac *hmac; 4366 unsigned int sig_len; 4367 __u16 key_id; 4368 4369 /* Pull in the auth header, so we can do some more verification */ 4370 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4371 chunk->subh.auth_hdr = auth_hdr; 4372 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4373 4374 /* Make sure that we support the HMAC algorithm from the auth 4375 * chunk. 4376 */ 4377 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4378 return SCTP_IERROR_AUTH_BAD_HMAC; 4379 4380 /* Make sure that the provided shared key identifier has been 4381 * configured 4382 */ 4383 key_id = ntohs(auth_hdr->shkey_id); 4384 if (key_id != asoc->active_key_id) { 4385 sh_key = sctp_auth_get_shkey(asoc, key_id); 4386 if (!sh_key) 4387 return SCTP_IERROR_AUTH_BAD_KEYID; 4388 } 4389 4390 /* Make sure that the length of the signature matches what 4391 * we expect. 4392 */ 4393 sig_len = ntohs(chunk->chunk_hdr->length) - 4394 sizeof(struct sctp_auth_chunk); 4395 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4396 if (sig_len != hmac->hmac_len) 4397 return SCTP_IERROR_PROTO_VIOLATION; 4398 4399 /* Now that we've done validation checks, we can compute and 4400 * verify the hmac. The steps involved are: 4401 * 1. Save the digest from the chunk. 4402 * 2. Zero out the digest in the chunk. 4403 * 3. Compute the new digest 4404 * 4. Compare saved and new digests. 4405 */ 4406 digest = (u8 *)(auth_hdr + 1); 4407 skb_pull(chunk->skb, sig_len); 4408 4409 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4410 if (!save_digest) 4411 goto nomem; 4412 4413 memset(digest, 0, sig_len); 4414 4415 sctp_auth_calculate_hmac(asoc, chunk->skb, 4416 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4417 sh_key, GFP_ATOMIC); 4418 4419 /* Discard the packet if the digests do not match */ 4420 if (crypto_memneq(save_digest, digest, sig_len)) { 4421 kfree(save_digest); 4422 return SCTP_IERROR_BAD_SIG; 4423 } 4424 4425 kfree(save_digest); 4426 chunk->auth = 1; 4427 4428 return SCTP_IERROR_NO_ERROR; 4429 nomem: 4430 return SCTP_IERROR_NOMEM; 4431 } 4432 4433 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4434 const struct sctp_endpoint *ep, 4435 const struct sctp_association *asoc, 4436 const union sctp_subtype type, 4437 void *arg, struct sctp_cmd_seq *commands) 4438 { 4439 struct sctp_chunk *chunk = arg; 4440 struct sctp_authhdr *auth_hdr; 4441 struct sctp_chunk *err_chunk; 4442 enum sctp_ierror error; 4443 4444 /* Make sure that the peer has AUTH capable */ 4445 if (!asoc->peer.auth_capable) 4446 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4447 4448 if (!sctp_vtag_verify(chunk, asoc)) { 4449 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4450 SCTP_NULL()); 4451 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4452 } 4453 4454 /* Make sure that the AUTH chunk has valid length. */ 4455 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4456 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4457 commands); 4458 4459 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4460 error = sctp_sf_authenticate(asoc, chunk); 4461 switch (error) { 4462 case SCTP_IERROR_AUTH_BAD_HMAC: 4463 /* Generate the ERROR chunk and discard the rest 4464 * of the packet 4465 */ 4466 err_chunk = sctp_make_op_error(asoc, chunk, 4467 SCTP_ERROR_UNSUP_HMAC, 4468 &auth_hdr->hmac_id, 4469 sizeof(__u16), 0); 4470 if (err_chunk) { 4471 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4472 SCTP_CHUNK(err_chunk)); 4473 } 4474 fallthrough; 4475 case SCTP_IERROR_AUTH_BAD_KEYID: 4476 case SCTP_IERROR_BAD_SIG: 4477 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4478 4479 case SCTP_IERROR_PROTO_VIOLATION: 4480 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4481 commands); 4482 4483 case SCTP_IERROR_NOMEM: 4484 return SCTP_DISPOSITION_NOMEM; 4485 4486 default: /* Prevent gcc warnings */ 4487 break; 4488 } 4489 4490 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4491 struct sctp_ulpevent *ev; 4492 4493 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4494 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4495 4496 if (!ev) 4497 return SCTP_DISPOSITION_NOMEM; 4498 4499 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4500 SCTP_ULPEVENT(ev)); 4501 } 4502 4503 return SCTP_DISPOSITION_CONSUME; 4504 } 4505 4506 /* 4507 * Process an unknown chunk. 4508 * 4509 * Section: 3.2. Also, 2.1 in the implementor's guide. 4510 * 4511 * Chunk Types are encoded such that the highest-order two bits specify 4512 * the action that must be taken if the processing endpoint does not 4513 * recognize the Chunk Type. 4514 * 4515 * 00 - Stop processing this SCTP packet and discard it, do not process 4516 * any further chunks within it. 4517 * 4518 * 01 - Stop processing this SCTP packet and discard it, do not process 4519 * any further chunks within it, and report the unrecognized 4520 * chunk in an 'Unrecognized Chunk Type'. 4521 * 4522 * 10 - Skip this chunk and continue processing. 4523 * 4524 * 11 - Skip this chunk and continue processing, but report in an ERROR 4525 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4526 * 4527 * The return value is the disposition of the chunk. 4528 */ 4529 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4530 const struct sctp_endpoint *ep, 4531 const struct sctp_association *asoc, 4532 const union sctp_subtype type, 4533 void *arg, 4534 struct sctp_cmd_seq *commands) 4535 { 4536 struct sctp_chunk *unk_chunk = arg; 4537 struct sctp_chunk *err_chunk; 4538 struct sctp_chunkhdr *hdr; 4539 4540 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4541 4542 if (!sctp_vtag_verify(unk_chunk, asoc)) 4543 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4544 4545 /* Make sure that the chunk has a valid length. 4546 * Since we don't know the chunk type, we use a general 4547 * chunkhdr structure to make a comparison. 4548 */ 4549 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4550 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4551 commands); 4552 4553 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4554 case SCTP_CID_ACTION_DISCARD: 4555 /* Discard the packet. */ 4556 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4557 case SCTP_CID_ACTION_DISCARD_ERR: 4558 /* Generate an ERROR chunk as response. */ 4559 hdr = unk_chunk->chunk_hdr; 4560 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4561 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4562 SCTP_PAD4(ntohs(hdr->length)), 4563 0); 4564 if (err_chunk) { 4565 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4566 SCTP_CHUNK(err_chunk)); 4567 } 4568 4569 /* Discard the packet. */ 4570 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4571 return SCTP_DISPOSITION_CONSUME; 4572 case SCTP_CID_ACTION_SKIP: 4573 /* Skip the chunk. */ 4574 return SCTP_DISPOSITION_DISCARD; 4575 case SCTP_CID_ACTION_SKIP_ERR: 4576 /* Generate an ERROR chunk as response. */ 4577 hdr = unk_chunk->chunk_hdr; 4578 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4579 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4580 SCTP_PAD4(ntohs(hdr->length)), 4581 0); 4582 if (err_chunk) { 4583 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4584 SCTP_CHUNK(err_chunk)); 4585 } 4586 /* Skip the chunk. */ 4587 return SCTP_DISPOSITION_CONSUME; 4588 default: 4589 break; 4590 } 4591 4592 return SCTP_DISPOSITION_DISCARD; 4593 } 4594 4595 /* 4596 * Discard the chunk. 4597 * 4598 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4599 * [Too numerous to mention...] 4600 * Verification Tag: No verification needed. 4601 * Inputs 4602 * (endpoint, asoc, chunk) 4603 * 4604 * Outputs 4605 * (asoc, reply_msg, msg_up, timers, counters) 4606 * 4607 * The return value is the disposition of the chunk. 4608 */ 4609 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4610 const struct sctp_endpoint *ep, 4611 const struct sctp_association *asoc, 4612 const union sctp_subtype type, 4613 void *arg, 4614 struct sctp_cmd_seq *commands) 4615 { 4616 struct sctp_chunk *chunk = arg; 4617 4618 if (asoc && !sctp_vtag_verify(chunk, asoc)) 4619 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4620 4621 /* Make sure that the chunk has a valid length. 4622 * Since we don't know the chunk type, we use a general 4623 * chunkhdr structure to make a comparison. 4624 */ 4625 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4626 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4627 commands); 4628 4629 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4630 4631 return SCTP_DISPOSITION_DISCARD; 4632 } 4633 4634 /* 4635 * Discard the whole packet. 4636 * 4637 * Section: 8.4 2) 4638 * 4639 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4640 * silently discard the OOTB packet and take no further action. 4641 * 4642 * Verification Tag: No verification necessary 4643 * 4644 * Inputs 4645 * (endpoint, asoc, chunk) 4646 * 4647 * Outputs 4648 * (asoc, reply_msg, msg_up, timers, counters) 4649 * 4650 * The return value is the disposition of the chunk. 4651 */ 4652 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4653 const struct sctp_endpoint *ep, 4654 const struct sctp_association *asoc, 4655 const union sctp_subtype type, 4656 void *arg, struct sctp_cmd_seq *commands) 4657 { 4658 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4659 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4660 4661 return SCTP_DISPOSITION_CONSUME; 4662 } 4663 4664 4665 /* 4666 * The other end is violating protocol. 4667 * 4668 * Section: Not specified 4669 * Verification Tag: Not specified 4670 * Inputs 4671 * (endpoint, asoc, chunk) 4672 * 4673 * Outputs 4674 * (asoc, reply_msg, msg_up, timers, counters) 4675 * 4676 * We simply tag the chunk as a violation. The state machine will log 4677 * the violation and continue. 4678 */ 4679 enum sctp_disposition sctp_sf_violation(struct net *net, 4680 const struct sctp_endpoint *ep, 4681 const struct sctp_association *asoc, 4682 const union sctp_subtype type, 4683 void *arg, 4684 struct sctp_cmd_seq *commands) 4685 { 4686 struct sctp_chunk *chunk = arg; 4687 4688 if (!sctp_vtag_verify(chunk, asoc)) 4689 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4690 4691 /* Make sure that the chunk has a valid length. */ 4692 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4693 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4694 commands); 4695 4696 return SCTP_DISPOSITION_VIOLATION; 4697 } 4698 4699 /* 4700 * Common function to handle a protocol violation. 4701 */ 4702 static enum sctp_disposition sctp_sf_abort_violation( 4703 struct net *net, 4704 const struct sctp_endpoint *ep, 4705 const struct sctp_association *asoc, 4706 void *arg, 4707 struct sctp_cmd_seq *commands, 4708 const __u8 *payload, 4709 const size_t paylen) 4710 { 4711 struct sctp_packet *packet = NULL; 4712 struct sctp_chunk *chunk = arg; 4713 struct sctp_chunk *abort = NULL; 4714 4715 /* SCTP-AUTH, Section 6.3: 4716 * It should be noted that if the receiver wants to tear 4717 * down an association in an authenticated way only, the 4718 * handling of malformed packets should not result in 4719 * tearing down the association. 4720 * 4721 * This means that if we only want to abort associations 4722 * in an authenticated way (i.e AUTH+ABORT), then we 4723 * can't destroy this association just because the packet 4724 * was malformed. 4725 */ 4726 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4727 goto discard; 4728 4729 /* Make the abort chunk. */ 4730 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4731 if (!abort) 4732 goto nomem; 4733 4734 if (asoc) { 4735 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4736 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4737 !asoc->peer.i.init_tag) { 4738 struct sctp_initack_chunk *initack; 4739 4740 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4741 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4742 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4743 else { 4744 unsigned int inittag; 4745 4746 inittag = ntohl(initack->init_hdr.init_tag); 4747 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4748 SCTP_U32(inittag)); 4749 } 4750 } 4751 4752 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4753 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4754 4755 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4756 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4757 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4758 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4759 SCTP_ERROR(ECONNREFUSED)); 4760 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4761 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4762 } else { 4763 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4764 SCTP_ERROR(ECONNABORTED)); 4765 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4766 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4767 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4768 } 4769 } else { 4770 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4771 4772 if (!packet) 4773 goto nomem_pkt; 4774 4775 if (sctp_test_T_bit(abort)) 4776 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4777 4778 abort->skb->sk = ep->base.sk; 4779 4780 sctp_packet_append_chunk(packet, abort); 4781 4782 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4783 SCTP_PACKET(packet)); 4784 4785 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4786 } 4787 4788 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4789 4790 discard: 4791 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4792 return SCTP_DISPOSITION_ABORT; 4793 4794 nomem_pkt: 4795 sctp_chunk_free(abort); 4796 nomem: 4797 return SCTP_DISPOSITION_NOMEM; 4798 } 4799 4800 /* 4801 * Handle a protocol violation when the chunk length is invalid. 4802 * "Invalid" length is identified as smaller than the minimal length a 4803 * given chunk can be. For example, a SACK chunk has invalid length 4804 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4805 * 4806 * We inform the other end by sending an ABORT with a Protocol Violation 4807 * error code. 4808 * 4809 * Section: Not specified 4810 * Verification Tag: Nothing to do 4811 * Inputs 4812 * (endpoint, asoc, chunk) 4813 * 4814 * Outputs 4815 * (reply_msg, msg_up, counters) 4816 * 4817 * Generate an ABORT chunk and terminate the association. 4818 */ 4819 static enum sctp_disposition sctp_sf_violation_chunklen( 4820 struct net *net, 4821 const struct sctp_endpoint *ep, 4822 const struct sctp_association *asoc, 4823 const union sctp_subtype type, 4824 void *arg, 4825 struct sctp_cmd_seq *commands) 4826 { 4827 static const char err_str[] = "The following chunk had invalid length:"; 4828 4829 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4830 sizeof(err_str)); 4831 } 4832 4833 /* 4834 * Handle a protocol violation when the parameter length is invalid. 4835 * If the length is smaller than the minimum length of a given parameter, 4836 * or accumulated length in multi parameters exceeds the end of the chunk, 4837 * the length is considered as invalid. 4838 */ 4839 static enum sctp_disposition sctp_sf_violation_paramlen( 4840 struct net *net, 4841 const struct sctp_endpoint *ep, 4842 const struct sctp_association *asoc, 4843 const union sctp_subtype type, 4844 void *arg, void *ext, 4845 struct sctp_cmd_seq *commands) 4846 { 4847 struct sctp_paramhdr *param = ext; 4848 struct sctp_chunk *abort = NULL; 4849 struct sctp_chunk *chunk = arg; 4850 4851 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4852 goto discard; 4853 4854 /* Make the abort chunk. */ 4855 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4856 if (!abort) 4857 goto nomem; 4858 4859 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4860 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4861 4862 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4863 SCTP_ERROR(ECONNABORTED)); 4864 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4865 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4866 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4867 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4868 4869 discard: 4870 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4871 return SCTP_DISPOSITION_ABORT; 4872 nomem: 4873 return SCTP_DISPOSITION_NOMEM; 4874 } 4875 4876 /* Handle a protocol violation when the peer trying to advance the 4877 * cumulative tsn ack to a point beyond the max tsn currently sent. 4878 * 4879 * We inform the other end by sending an ABORT with a Protocol Violation 4880 * error code. 4881 */ 4882 static enum sctp_disposition sctp_sf_violation_ctsn( 4883 struct net *net, 4884 const struct sctp_endpoint *ep, 4885 const struct sctp_association *asoc, 4886 const union sctp_subtype type, 4887 void *arg, 4888 struct sctp_cmd_seq *commands) 4889 { 4890 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4891 4892 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4893 sizeof(err_str)); 4894 } 4895 4896 /* Handle protocol violation of an invalid chunk bundling. For example, 4897 * when we have an association and we receive bundled INIT-ACK, or 4898 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle" 4899 * statement from the specs. Additionally, there might be an attacker 4900 * on the path and we may not want to continue this communication. 4901 */ 4902 static enum sctp_disposition sctp_sf_violation_chunk( 4903 struct net *net, 4904 const struct sctp_endpoint *ep, 4905 const struct sctp_association *asoc, 4906 const union sctp_subtype type, 4907 void *arg, 4908 struct sctp_cmd_seq *commands) 4909 { 4910 static const char err_str[] = "The following chunk violates protocol:"; 4911 4912 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4913 sizeof(err_str)); 4914 } 4915 /*************************************************************************** 4916 * These are the state functions for handling primitive (Section 10) events. 4917 ***************************************************************************/ 4918 /* 4919 * sctp_sf_do_prm_asoc 4920 * 4921 * Section: 10.1 ULP-to-SCTP 4922 * B) Associate 4923 * 4924 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4925 * outbound stream count) 4926 * -> association id [,destination transport addr list] [,outbound stream 4927 * count] 4928 * 4929 * This primitive allows the upper layer to initiate an association to a 4930 * specific peer endpoint. 4931 * 4932 * The peer endpoint shall be specified by one of the transport addresses 4933 * which defines the endpoint (see Section 1.4). If the local SCTP 4934 * instance has not been initialized, the ASSOCIATE is considered an 4935 * error. 4936 * [This is not relevant for the kernel implementation since we do all 4937 * initialization at boot time. It we hadn't initialized we wouldn't 4938 * get anywhere near this code.] 4939 * 4940 * An association id, which is a local handle to the SCTP association, 4941 * will be returned on successful establishment of the association. If 4942 * SCTP is not able to open an SCTP association with the peer endpoint, 4943 * an error is returned. 4944 * [In the kernel implementation, the struct sctp_association needs to 4945 * be created BEFORE causing this primitive to run.] 4946 * 4947 * Other association parameters may be returned, including the 4948 * complete destination transport addresses of the peer as well as the 4949 * outbound stream count of the local endpoint. One of the transport 4950 * address from the returned destination addresses will be selected by 4951 * the local endpoint as default primary path for sending SCTP packets 4952 * to this peer. The returned "destination transport addr list" can 4953 * be used by the ULP to change the default primary path or to force 4954 * sending a packet to a specific transport address. [All of this 4955 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4956 * function.] 4957 * 4958 * Mandatory attributes: 4959 * 4960 * o local SCTP instance name - obtained from the INITIALIZE operation. 4961 * [This is the argument asoc.] 4962 * o destination transport addr - specified as one of the transport 4963 * addresses of the peer endpoint with which the association is to be 4964 * established. 4965 * [This is asoc->peer.active_path.] 4966 * o outbound stream count - the number of outbound streams the ULP 4967 * would like to open towards this peer endpoint. 4968 * [BUG: This is not currently implemented.] 4969 * Optional attributes: 4970 * 4971 * None. 4972 * 4973 * The return value is a disposition. 4974 */ 4975 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4976 const struct sctp_endpoint *ep, 4977 const struct sctp_association *asoc, 4978 const union sctp_subtype type, 4979 void *arg, 4980 struct sctp_cmd_seq *commands) 4981 { 4982 struct sctp_association *my_asoc; 4983 struct sctp_chunk *repl; 4984 4985 /* The comment below says that we enter COOKIE-WAIT AFTER 4986 * sending the INIT, but that doesn't actually work in our 4987 * implementation... 4988 */ 4989 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4990 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4991 4992 /* RFC 2960 5.1 Normal Establishment of an Association 4993 * 4994 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4995 * must provide its Verification Tag (Tag_A) in the Initiate 4996 * Tag field. Tag_A SHOULD be a random number in the range of 4997 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4998 */ 4999 5000 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 5001 if (!repl) 5002 goto nomem; 5003 5004 /* Choose transport for INIT. */ 5005 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5006 SCTP_CHUNK(repl)); 5007 5008 /* Cast away the const modifier, as we want to just 5009 * rerun it through as a sideffect. 5010 */ 5011 my_asoc = (struct sctp_association *)asoc; 5012 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 5013 5014 /* After sending the INIT, "A" starts the T1-init timer and 5015 * enters the COOKIE-WAIT state. 5016 */ 5017 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5018 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5019 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5020 return SCTP_DISPOSITION_CONSUME; 5021 5022 nomem: 5023 return SCTP_DISPOSITION_NOMEM; 5024 } 5025 5026 /* 5027 * Process the SEND primitive. 5028 * 5029 * Section: 10.1 ULP-to-SCTP 5030 * E) Send 5031 * 5032 * Format: SEND(association id, buffer address, byte count [,context] 5033 * [,stream id] [,life time] [,destination transport address] 5034 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 5035 * -> result 5036 * 5037 * This is the main method to send user data via SCTP. 5038 * 5039 * Mandatory attributes: 5040 * 5041 * o association id - local handle to the SCTP association 5042 * 5043 * o buffer address - the location where the user message to be 5044 * transmitted is stored; 5045 * 5046 * o byte count - The size of the user data in number of bytes; 5047 * 5048 * Optional attributes: 5049 * 5050 * o context - an optional 32 bit integer that will be carried in the 5051 * sending failure notification to the ULP if the transportation of 5052 * this User Message fails. 5053 * 5054 * o stream id - to indicate which stream to send the data on. If not 5055 * specified, stream 0 will be used. 5056 * 5057 * o life time - specifies the life time of the user data. The user data 5058 * will not be sent by SCTP after the life time expires. This 5059 * parameter can be used to avoid efforts to transmit stale 5060 * user messages. SCTP notifies the ULP if the data cannot be 5061 * initiated to transport (i.e. sent to the destination via SCTP's 5062 * send primitive) within the life time variable. However, the 5063 * user data will be transmitted if SCTP has attempted to transmit a 5064 * chunk before the life time expired. 5065 * 5066 * o destination transport address - specified as one of the destination 5067 * transport addresses of the peer endpoint to which this packet 5068 * should be sent. Whenever possible, SCTP should use this destination 5069 * transport address for sending the packets, instead of the current 5070 * primary path. 5071 * 5072 * o unorder flag - this flag, if present, indicates that the user 5073 * would like the data delivered in an unordered fashion to the peer 5074 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 5075 * message). 5076 * 5077 * o no-bundle flag - instructs SCTP not to bundle this user data with 5078 * other outbound DATA chunks. SCTP MAY still bundle even when 5079 * this flag is present, when faced with network congestion. 5080 * 5081 * o payload protocol-id - A 32 bit unsigned integer that is to be 5082 * passed to the peer indicating the type of payload protocol data 5083 * being transmitted. This value is passed as opaque data by SCTP. 5084 * 5085 * The return value is the disposition. 5086 */ 5087 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5088 const struct sctp_endpoint *ep, 5089 const struct sctp_association *asoc, 5090 const union sctp_subtype type, 5091 void *arg, 5092 struct sctp_cmd_seq *commands) 5093 { 5094 struct sctp_datamsg *msg = arg; 5095 5096 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5097 return SCTP_DISPOSITION_CONSUME; 5098 } 5099 5100 /* 5101 * Process the SHUTDOWN primitive. 5102 * 5103 * Section: 10.1: 5104 * C) Shutdown 5105 * 5106 * Format: SHUTDOWN(association id) 5107 * -> result 5108 * 5109 * Gracefully closes an association. Any locally queued user data 5110 * will be delivered to the peer. The association will be terminated only 5111 * after the peer acknowledges all the SCTP packets sent. A success code 5112 * will be returned on successful termination of the association. If 5113 * attempting to terminate the association results in a failure, an error 5114 * code shall be returned. 5115 * 5116 * Mandatory attributes: 5117 * 5118 * o association id - local handle to the SCTP association 5119 * 5120 * Optional attributes: 5121 * 5122 * None. 5123 * 5124 * The return value is the disposition. 5125 */ 5126 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5127 struct net *net, 5128 const struct sctp_endpoint *ep, 5129 const struct sctp_association *asoc, 5130 const union sctp_subtype type, 5131 void *arg, 5132 struct sctp_cmd_seq *commands) 5133 { 5134 enum sctp_disposition disposition; 5135 5136 /* From 9.2 Shutdown of an Association 5137 * Upon receipt of the SHUTDOWN primitive from its upper 5138 * layer, the endpoint enters SHUTDOWN-PENDING state and 5139 * remains there until all outstanding data has been 5140 * acknowledged by its peer. The endpoint accepts no new data 5141 * from its upper layer, but retransmits data to the far end 5142 * if necessary to fill gaps. 5143 */ 5144 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5145 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5146 5147 disposition = SCTP_DISPOSITION_CONSUME; 5148 if (sctp_outq_is_empty(&asoc->outqueue)) { 5149 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5150 arg, commands); 5151 } 5152 5153 return disposition; 5154 } 5155 5156 /* 5157 * Process the ABORT primitive. 5158 * 5159 * Section: 10.1: 5160 * C) Abort 5161 * 5162 * Format: Abort(association id [, cause code]) 5163 * -> result 5164 * 5165 * Ungracefully closes an association. Any locally queued user data 5166 * will be discarded and an ABORT chunk is sent to the peer. A success code 5167 * will be returned on successful abortion of the association. If 5168 * attempting to abort the association results in a failure, an error 5169 * code shall be returned. 5170 * 5171 * Mandatory attributes: 5172 * 5173 * o association id - local handle to the SCTP association 5174 * 5175 * Optional attributes: 5176 * 5177 * o cause code - reason of the abort to be passed to the peer 5178 * 5179 * None. 5180 * 5181 * The return value is the disposition. 5182 */ 5183 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5184 struct net *net, 5185 const struct sctp_endpoint *ep, 5186 const struct sctp_association *asoc, 5187 const union sctp_subtype type, 5188 void *arg, 5189 struct sctp_cmd_seq *commands) 5190 { 5191 /* From 9.1 Abort of an Association 5192 * Upon receipt of the ABORT primitive from its upper 5193 * layer, the endpoint enters CLOSED state and 5194 * discard all outstanding data has been 5195 * acknowledged by its peer. The endpoint accepts no new data 5196 * from its upper layer, but retransmits data to the far end 5197 * if necessary to fill gaps. 5198 */ 5199 struct sctp_chunk *abort = arg; 5200 5201 if (abort) 5202 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5203 5204 /* Even if we can't send the ABORT due to low memory delete the 5205 * TCB. This is a departure from our typical NOMEM handling. 5206 */ 5207 5208 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5209 SCTP_ERROR(ECONNABORTED)); 5210 /* Delete the established association. */ 5211 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5212 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5213 5214 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5215 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5216 5217 return SCTP_DISPOSITION_ABORT; 5218 } 5219 5220 /* We tried an illegal operation on an association which is closed. */ 5221 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5222 const struct sctp_endpoint *ep, 5223 const struct sctp_association *asoc, 5224 const union sctp_subtype type, 5225 void *arg, 5226 struct sctp_cmd_seq *commands) 5227 { 5228 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5229 return SCTP_DISPOSITION_CONSUME; 5230 } 5231 5232 /* We tried an illegal operation on an association which is shutting 5233 * down. 5234 */ 5235 enum sctp_disposition sctp_sf_error_shutdown( 5236 struct net *net, 5237 const struct sctp_endpoint *ep, 5238 const struct sctp_association *asoc, 5239 const union sctp_subtype type, 5240 void *arg, 5241 struct sctp_cmd_seq *commands) 5242 { 5243 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5244 SCTP_ERROR(-ESHUTDOWN)); 5245 return SCTP_DISPOSITION_CONSUME; 5246 } 5247 5248 /* 5249 * sctp_cookie_wait_prm_shutdown 5250 * 5251 * Section: 4 Note: 2 5252 * Verification Tag: 5253 * Inputs 5254 * (endpoint, asoc) 5255 * 5256 * The RFC does not explicitly address this issue, but is the route through the 5257 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5258 * 5259 * Outputs 5260 * (timers) 5261 */ 5262 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5263 struct net *net, 5264 const struct sctp_endpoint *ep, 5265 const struct sctp_association *asoc, 5266 const union sctp_subtype type, 5267 void *arg, 5268 struct sctp_cmd_seq *commands) 5269 { 5270 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5271 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5272 5273 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5274 SCTP_STATE(SCTP_STATE_CLOSED)); 5275 5276 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5277 5278 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5279 5280 return SCTP_DISPOSITION_DELETE_TCB; 5281 } 5282 5283 /* 5284 * sctp_cookie_echoed_prm_shutdown 5285 * 5286 * Section: 4 Note: 2 5287 * Verification Tag: 5288 * Inputs 5289 * (endpoint, asoc) 5290 * 5291 * The RFC does not explicitly address this issue, but is the route through the 5292 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5293 * 5294 * Outputs 5295 * (timers) 5296 */ 5297 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5298 struct net *net, 5299 const struct sctp_endpoint *ep, 5300 const struct sctp_association *asoc, 5301 const union sctp_subtype type, 5302 void *arg, 5303 struct sctp_cmd_seq *commands) 5304 { 5305 /* There is a single T1 timer, so we should be able to use 5306 * common function with the COOKIE-WAIT state. 5307 */ 5308 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5309 } 5310 5311 /* 5312 * sctp_sf_cookie_wait_prm_abort 5313 * 5314 * Section: 4 Note: 2 5315 * Verification Tag: 5316 * Inputs 5317 * (endpoint, asoc) 5318 * 5319 * The RFC does not explicitly address this issue, but is the route through the 5320 * state table when someone issues an abort while in COOKIE_WAIT state. 5321 * 5322 * Outputs 5323 * (timers) 5324 */ 5325 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5326 struct net *net, 5327 const struct sctp_endpoint *ep, 5328 const struct sctp_association *asoc, 5329 const union sctp_subtype type, 5330 void *arg, 5331 struct sctp_cmd_seq *commands) 5332 { 5333 struct sctp_chunk *abort = arg; 5334 5335 /* Stop T1-init timer */ 5336 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5337 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5338 5339 if (abort) 5340 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5341 5342 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5343 SCTP_STATE(SCTP_STATE_CLOSED)); 5344 5345 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5346 5347 /* Even if we can't send the ABORT due to low memory delete the 5348 * TCB. This is a departure from our typical NOMEM handling. 5349 */ 5350 5351 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5352 SCTP_ERROR(ECONNREFUSED)); 5353 /* Delete the established association. */ 5354 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5355 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5356 5357 return SCTP_DISPOSITION_ABORT; 5358 } 5359 5360 /* 5361 * sctp_sf_cookie_echoed_prm_abort 5362 * 5363 * Section: 4 Note: 3 5364 * Verification Tag: 5365 * Inputs 5366 * (endpoint, asoc) 5367 * 5368 * The RFC does not explcitly address this issue, but is the route through the 5369 * state table when someone issues an abort while in COOKIE_ECHOED state. 5370 * 5371 * Outputs 5372 * (timers) 5373 */ 5374 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5375 struct net *net, 5376 const struct sctp_endpoint *ep, 5377 const struct sctp_association *asoc, 5378 const union sctp_subtype type, 5379 void *arg, 5380 struct sctp_cmd_seq *commands) 5381 { 5382 /* There is a single T1 timer, so we should be able to use 5383 * common function with the COOKIE-WAIT state. 5384 */ 5385 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5386 } 5387 5388 /* 5389 * sctp_sf_shutdown_pending_prm_abort 5390 * 5391 * Inputs 5392 * (endpoint, asoc) 5393 * 5394 * The RFC does not explicitly address this issue, but is the route through the 5395 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5396 * 5397 * Outputs 5398 * (timers) 5399 */ 5400 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5401 struct net *net, 5402 const struct sctp_endpoint *ep, 5403 const struct sctp_association *asoc, 5404 const union sctp_subtype type, 5405 void *arg, 5406 struct sctp_cmd_seq *commands) 5407 { 5408 /* Stop the T5-shutdown guard timer. */ 5409 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5410 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5411 5412 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5413 } 5414 5415 /* 5416 * sctp_sf_shutdown_sent_prm_abort 5417 * 5418 * Inputs 5419 * (endpoint, asoc) 5420 * 5421 * The RFC does not explicitly address this issue, but is the route through the 5422 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5423 * 5424 * Outputs 5425 * (timers) 5426 */ 5427 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5428 struct net *net, 5429 const struct sctp_endpoint *ep, 5430 const struct sctp_association *asoc, 5431 const union sctp_subtype type, 5432 void *arg, 5433 struct sctp_cmd_seq *commands) 5434 { 5435 /* Stop the T2-shutdown timer. */ 5436 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5437 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5438 5439 /* Stop the T5-shutdown guard timer. */ 5440 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5441 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5442 5443 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5444 } 5445 5446 /* 5447 * sctp_sf_cookie_echoed_prm_abort 5448 * 5449 * Inputs 5450 * (endpoint, asoc) 5451 * 5452 * The RFC does not explcitly address this issue, but is the route through the 5453 * state table when someone issues an abort while in COOKIE_ECHOED state. 5454 * 5455 * Outputs 5456 * (timers) 5457 */ 5458 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5459 struct net *net, 5460 const struct sctp_endpoint *ep, 5461 const struct sctp_association *asoc, 5462 const union sctp_subtype type, 5463 void *arg, 5464 struct sctp_cmd_seq *commands) 5465 { 5466 /* The same T2 timer, so we should be able to use 5467 * common function with the SHUTDOWN-SENT state. 5468 */ 5469 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5470 } 5471 5472 /* 5473 * Process the REQUESTHEARTBEAT primitive 5474 * 5475 * 10.1 ULP-to-SCTP 5476 * J) Request Heartbeat 5477 * 5478 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5479 * 5480 * -> result 5481 * 5482 * Instructs the local endpoint to perform a HeartBeat on the specified 5483 * destination transport address of the given association. The returned 5484 * result should indicate whether the transmission of the HEARTBEAT 5485 * chunk to the destination address is successful. 5486 * 5487 * Mandatory attributes: 5488 * 5489 * o association id - local handle to the SCTP association 5490 * 5491 * o destination transport address - the transport address of the 5492 * association on which a heartbeat should be issued. 5493 */ 5494 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5495 struct net *net, 5496 const struct sctp_endpoint *ep, 5497 const struct sctp_association *asoc, 5498 const union sctp_subtype type, 5499 void *arg, 5500 struct sctp_cmd_seq *commands) 5501 { 5502 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5503 (struct sctp_transport *)arg, commands)) 5504 return SCTP_DISPOSITION_NOMEM; 5505 5506 /* 5507 * RFC 2960 (bis), section 8.3 5508 * 5509 * D) Request an on-demand HEARTBEAT on a specific destination 5510 * transport address of a given association. 5511 * 5512 * The endpoint should increment the respective error counter of 5513 * the destination transport address each time a HEARTBEAT is sent 5514 * to that address and not acknowledged within one RTO. 5515 * 5516 */ 5517 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5518 SCTP_TRANSPORT(arg)); 5519 return SCTP_DISPOSITION_CONSUME; 5520 } 5521 5522 /* 5523 * ADDIP Section 4.1 ASCONF Chunk Procedures 5524 * When an endpoint has an ASCONF signaled change to be sent to the 5525 * remote endpoint it should do A1 to A9 5526 */ 5527 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5528 const struct sctp_endpoint *ep, 5529 const struct sctp_association *asoc, 5530 const union sctp_subtype type, 5531 void *arg, 5532 struct sctp_cmd_seq *commands) 5533 { 5534 struct sctp_chunk *chunk = arg; 5535 5536 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5537 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5538 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5539 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5540 return SCTP_DISPOSITION_CONSUME; 5541 } 5542 5543 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5544 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5545 const struct sctp_endpoint *ep, 5546 const struct sctp_association *asoc, 5547 const union sctp_subtype type, 5548 void *arg, 5549 struct sctp_cmd_seq *commands) 5550 { 5551 struct sctp_chunk *chunk = arg; 5552 5553 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5554 return SCTP_DISPOSITION_CONSUME; 5555 } 5556 5557 /* 5558 * Ignore the primitive event 5559 * 5560 * The return value is the disposition of the primitive. 5561 */ 5562 enum sctp_disposition sctp_sf_ignore_primitive( 5563 struct net *net, 5564 const struct sctp_endpoint *ep, 5565 const struct sctp_association *asoc, 5566 const union sctp_subtype type, 5567 void *arg, 5568 struct sctp_cmd_seq *commands) 5569 { 5570 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5571 type.primitive); 5572 5573 return SCTP_DISPOSITION_DISCARD; 5574 } 5575 5576 /*************************************************************************** 5577 * These are the state functions for the OTHER events. 5578 ***************************************************************************/ 5579 5580 /* 5581 * When the SCTP stack has no more user data to send or retransmit, this 5582 * notification is given to the user. Also, at the time when a user app 5583 * subscribes to this event, if there is no data to be sent or 5584 * retransmit, the stack will immediately send up this notification. 5585 */ 5586 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5587 struct net *net, 5588 const struct sctp_endpoint *ep, 5589 const struct sctp_association *asoc, 5590 const union sctp_subtype type, 5591 void *arg, 5592 struct sctp_cmd_seq *commands) 5593 { 5594 struct sctp_ulpevent *event; 5595 5596 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5597 if (!event) 5598 return SCTP_DISPOSITION_NOMEM; 5599 5600 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5601 5602 return SCTP_DISPOSITION_CONSUME; 5603 } 5604 5605 /* 5606 * Start the shutdown negotiation. 5607 * 5608 * From Section 9.2: 5609 * Once all its outstanding data has been acknowledged, the endpoint 5610 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5611 * TSN Ack field the last sequential TSN it has received from the peer. 5612 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5613 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5614 * with the updated last sequential TSN received from its peer. 5615 * 5616 * The return value is the disposition. 5617 */ 5618 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5619 struct net *net, 5620 const struct sctp_endpoint *ep, 5621 const struct sctp_association *asoc, 5622 const union sctp_subtype type, 5623 void *arg, 5624 struct sctp_cmd_seq *commands) 5625 { 5626 struct sctp_chunk *reply; 5627 5628 /* Once all its outstanding data has been acknowledged, the 5629 * endpoint shall send a SHUTDOWN chunk to its peer including 5630 * in the Cumulative TSN Ack field the last sequential TSN it 5631 * has received from the peer. 5632 */ 5633 reply = sctp_make_shutdown(asoc, arg); 5634 if (!reply) 5635 goto nomem; 5636 5637 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5638 * T2-shutdown timer. 5639 */ 5640 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5641 5642 /* It shall then start the T2-shutdown timer */ 5643 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5644 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5645 5646 /* RFC 4960 Section 9.2 5647 * The sender of the SHUTDOWN MAY also start an overall guard timer 5648 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5649 */ 5650 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5651 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5652 5653 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5654 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5655 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5656 5657 /* and enter the SHUTDOWN-SENT state. */ 5658 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5659 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5660 5661 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5662 * 5663 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5664 * or SHUTDOWN-ACK. 5665 */ 5666 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5667 5668 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5669 5670 return SCTP_DISPOSITION_CONSUME; 5671 5672 nomem: 5673 return SCTP_DISPOSITION_NOMEM; 5674 } 5675 5676 /* 5677 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5678 * 5679 * From Section 9.2: 5680 * 5681 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5682 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5683 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5684 * endpoint must re-send the SHUTDOWN ACK. 5685 * 5686 * The return value is the disposition. 5687 */ 5688 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5689 struct net *net, 5690 const struct sctp_endpoint *ep, 5691 const struct sctp_association *asoc, 5692 const union sctp_subtype type, 5693 void *arg, 5694 struct sctp_cmd_seq *commands) 5695 { 5696 struct sctp_chunk *chunk = arg; 5697 struct sctp_chunk *reply; 5698 5699 /* There are 2 ways of getting here: 5700 * 1) called in response to a SHUTDOWN chunk 5701 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5702 * 5703 * For the case (2), the arg parameter is set to NULL. We need 5704 * to check that we have a chunk before accessing it's fields. 5705 */ 5706 if (chunk) { 5707 if (!sctp_vtag_verify(chunk, asoc)) 5708 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5709 commands); 5710 5711 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5712 if (!sctp_chunk_length_valid( 5713 chunk, sizeof(struct sctp_shutdown_chunk))) 5714 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5715 arg, commands); 5716 } 5717 5718 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5719 * shall send a SHUTDOWN ACK ... 5720 */ 5721 reply = sctp_make_shutdown_ack(asoc, chunk); 5722 if (!reply) 5723 goto nomem; 5724 5725 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5726 * the T2-shutdown timer. 5727 */ 5728 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5729 5730 /* and start/restart a T2-shutdown timer of its own, */ 5731 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5732 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5733 5734 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5735 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5736 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5737 5738 /* Enter the SHUTDOWN-ACK-SENT state. */ 5739 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5740 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5741 5742 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5743 * 5744 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5745 * or SHUTDOWN-ACK. 5746 */ 5747 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5748 5749 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5750 5751 return SCTP_DISPOSITION_CONSUME; 5752 5753 nomem: 5754 return SCTP_DISPOSITION_NOMEM; 5755 } 5756 5757 /* 5758 * Ignore the event defined as other 5759 * 5760 * The return value is the disposition of the event. 5761 */ 5762 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5763 const struct sctp_endpoint *ep, 5764 const struct sctp_association *asoc, 5765 const union sctp_subtype type, 5766 void *arg, 5767 struct sctp_cmd_seq *commands) 5768 { 5769 pr_debug("%s: the event other type:%d is ignored\n", 5770 __func__, type.other); 5771 5772 return SCTP_DISPOSITION_DISCARD; 5773 } 5774 5775 /************************************************************ 5776 * These are the state functions for handling timeout events. 5777 ************************************************************/ 5778 5779 /* 5780 * RTX Timeout 5781 * 5782 * Section: 6.3.3 Handle T3-rtx Expiration 5783 * 5784 * Whenever the retransmission timer T3-rtx expires for a destination 5785 * address, do the following: 5786 * [See below] 5787 * 5788 * The return value is the disposition of the chunk. 5789 */ 5790 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5791 const struct sctp_endpoint *ep, 5792 const struct sctp_association *asoc, 5793 const union sctp_subtype type, 5794 void *arg, 5795 struct sctp_cmd_seq *commands) 5796 { 5797 struct sctp_transport *transport = arg; 5798 5799 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5800 5801 if (asoc->overall_error_count >= asoc->max_retrans) { 5802 if (asoc->peer.zero_window_announced && 5803 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5804 /* 5805 * We are here likely because the receiver had its rwnd 5806 * closed for a while and we have not been able to 5807 * transmit the locally queued data within the maximum 5808 * retransmission attempts limit. Start the T5 5809 * shutdown guard timer to give the receiver one last 5810 * chance and some additional time to recover before 5811 * aborting. 5812 */ 5813 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5814 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5815 } else { 5816 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5817 SCTP_ERROR(ETIMEDOUT)); 5818 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5819 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5820 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5821 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5822 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5823 return SCTP_DISPOSITION_DELETE_TCB; 5824 } 5825 } 5826 5827 /* E1) For the destination address for which the timer 5828 * expires, adjust its ssthresh with rules defined in Section 5829 * 7.2.3 and set the cwnd <- MTU. 5830 */ 5831 5832 /* E2) For the destination address for which the timer 5833 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5834 * maximum value discussed in rule C7 above (RTO.max) may be 5835 * used to provide an upper bound to this doubling operation. 5836 */ 5837 5838 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5839 * outstanding DATA chunks for the address for which the 5840 * T3-rtx has expired will fit into a single packet, subject 5841 * to the MTU constraint for the path corresponding to the 5842 * destination transport address to which the retransmission 5843 * is being sent (this may be different from the address for 5844 * which the timer expires [see Section 6.4]). Call this 5845 * value K. Bundle and retransmit those K DATA chunks in a 5846 * single packet to the destination endpoint. 5847 * 5848 * Note: Any DATA chunks that were sent to the address for 5849 * which the T3-rtx timer expired but did not fit in one MTU 5850 * (rule E3 above), should be marked for retransmission and 5851 * sent as soon as cwnd allows (normally when a SACK arrives). 5852 */ 5853 5854 /* Do some failure management (Section 8.2). */ 5855 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5856 5857 /* NB: Rules E4 and F1 are implicit in R1. */ 5858 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5859 5860 return SCTP_DISPOSITION_CONSUME; 5861 } 5862 5863 /* 5864 * Generate delayed SACK on timeout 5865 * 5866 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5867 * 5868 * The guidelines on delayed acknowledgement algorithm specified in 5869 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5870 * acknowledgement SHOULD be generated for at least every second packet 5871 * (not every second DATA chunk) received, and SHOULD be generated 5872 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5873 * some situations it may be beneficial for an SCTP transmitter to be 5874 * more conservative than the algorithms detailed in this document 5875 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5876 * the following algorithms allow. 5877 */ 5878 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5879 const struct sctp_endpoint *ep, 5880 const struct sctp_association *asoc, 5881 const union sctp_subtype type, 5882 void *arg, 5883 struct sctp_cmd_seq *commands) 5884 { 5885 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5886 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5887 return SCTP_DISPOSITION_CONSUME; 5888 } 5889 5890 /* 5891 * sctp_sf_t1_init_timer_expire 5892 * 5893 * Section: 4 Note: 2 5894 * Verification Tag: 5895 * Inputs 5896 * (endpoint, asoc) 5897 * 5898 * RFC 2960 Section 4 Notes 5899 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5900 * and re-start the T1-init timer without changing state. This MUST 5901 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5902 * endpoint MUST abort the initialization process and report the 5903 * error to SCTP user. 5904 * 5905 * Outputs 5906 * (timers, events) 5907 * 5908 */ 5909 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5910 struct net *net, 5911 const struct sctp_endpoint *ep, 5912 const struct sctp_association *asoc, 5913 const union sctp_subtype type, 5914 void *arg, 5915 struct sctp_cmd_seq *commands) 5916 { 5917 int attempts = asoc->init_err_counter + 1; 5918 struct sctp_chunk *repl = NULL; 5919 struct sctp_bind_addr *bp; 5920 5921 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5922 5923 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5924 5925 if (attempts <= asoc->max_init_attempts) { 5926 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5927 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5928 if (!repl) 5929 return SCTP_DISPOSITION_NOMEM; 5930 5931 /* Choose transport for INIT. */ 5932 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5933 SCTP_CHUNK(repl)); 5934 5935 /* Issue a sideeffect to do the needed accounting. */ 5936 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5937 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5938 5939 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5940 } else { 5941 pr_debug("%s: giving up on INIT, attempts:%d " 5942 "max_init_attempts:%d\n", __func__, attempts, 5943 asoc->max_init_attempts); 5944 5945 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5946 SCTP_ERROR(ETIMEDOUT)); 5947 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5948 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5949 return SCTP_DISPOSITION_DELETE_TCB; 5950 } 5951 5952 return SCTP_DISPOSITION_CONSUME; 5953 } 5954 5955 /* 5956 * sctp_sf_t1_cookie_timer_expire 5957 * 5958 * Section: 4 Note: 2 5959 * Verification Tag: 5960 * Inputs 5961 * (endpoint, asoc) 5962 * 5963 * RFC 2960 Section 4 Notes 5964 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5965 * COOKIE ECHO and re-start the T1-cookie timer without changing 5966 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5967 * After that, the endpoint MUST abort the initialization process and 5968 * report the error to SCTP user. 5969 * 5970 * Outputs 5971 * (timers, events) 5972 * 5973 */ 5974 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5975 struct net *net, 5976 const struct sctp_endpoint *ep, 5977 const struct sctp_association *asoc, 5978 const union sctp_subtype type, 5979 void *arg, 5980 struct sctp_cmd_seq *commands) 5981 { 5982 int attempts = asoc->init_err_counter + 1; 5983 struct sctp_chunk *repl = NULL; 5984 5985 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5986 5987 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5988 5989 if (attempts <= asoc->max_init_attempts) { 5990 repl = sctp_make_cookie_echo(asoc, NULL); 5991 if (!repl) 5992 return SCTP_DISPOSITION_NOMEM; 5993 5994 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5995 SCTP_CHUNK(repl)); 5996 /* Issue a sideeffect to do the needed accounting. */ 5997 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5998 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5999 6000 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 6001 } else { 6002 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6003 SCTP_ERROR(ETIMEDOUT)); 6004 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 6005 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6006 return SCTP_DISPOSITION_DELETE_TCB; 6007 } 6008 6009 return SCTP_DISPOSITION_CONSUME; 6010 } 6011 6012 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 6013 * with the updated last sequential TSN received from its peer. 6014 * 6015 * An endpoint should limit the number of retransmission of the 6016 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 6017 * If this threshold is exceeded the endpoint should destroy the TCB and 6018 * MUST report the peer endpoint unreachable to the upper layer (and 6019 * thus the association enters the CLOSED state). The reception of any 6020 * packet from its peer (i.e. as the peer sends all of its queued DATA 6021 * chunks) should clear the endpoint's retransmission count and restart 6022 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 6023 * all of its queued DATA chunks that have not yet been sent. 6024 */ 6025 enum sctp_disposition sctp_sf_t2_timer_expire( 6026 struct net *net, 6027 const struct sctp_endpoint *ep, 6028 const struct sctp_association *asoc, 6029 const union sctp_subtype type, 6030 void *arg, 6031 struct sctp_cmd_seq *commands) 6032 { 6033 struct sctp_chunk *reply = NULL; 6034 6035 pr_debug("%s: timer T2 expired\n", __func__); 6036 6037 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 6038 6039 ((struct sctp_association *)asoc)->shutdown_retries++; 6040 6041 if (asoc->overall_error_count >= asoc->max_retrans) { 6042 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6043 SCTP_ERROR(ETIMEDOUT)); 6044 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 6045 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6046 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6047 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6048 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6049 return SCTP_DISPOSITION_DELETE_TCB; 6050 } 6051 6052 switch (asoc->state) { 6053 case SCTP_STATE_SHUTDOWN_SENT: 6054 reply = sctp_make_shutdown(asoc, NULL); 6055 break; 6056 6057 case SCTP_STATE_SHUTDOWN_ACK_SENT: 6058 reply = sctp_make_shutdown_ack(asoc, NULL); 6059 break; 6060 6061 default: 6062 BUG(); 6063 break; 6064 } 6065 6066 if (!reply) 6067 goto nomem; 6068 6069 /* Do some failure management (Section 8.2). 6070 * If we remove the transport an SHUTDOWN was last sent to, don't 6071 * do failure management. 6072 */ 6073 if (asoc->shutdown_last_sent_to) 6074 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6075 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 6076 6077 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 6078 * the T2-shutdown timer. 6079 */ 6080 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6081 6082 /* Restart the T2-shutdown timer. */ 6083 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6084 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6085 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6086 return SCTP_DISPOSITION_CONSUME; 6087 6088 nomem: 6089 return SCTP_DISPOSITION_NOMEM; 6090 } 6091 6092 /* 6093 * ADDIP Section 4.1 ASCONF Chunk Procedures 6094 * If the T4 RTO timer expires the endpoint should do B1 to B5 6095 */ 6096 enum sctp_disposition sctp_sf_t4_timer_expire( 6097 struct net *net, 6098 const struct sctp_endpoint *ep, 6099 const struct sctp_association *asoc, 6100 const union sctp_subtype type, 6101 void *arg, 6102 struct sctp_cmd_seq *commands) 6103 { 6104 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6105 struct sctp_transport *transport = chunk->transport; 6106 6107 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6108 6109 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6110 * detection on the appropriate destination address as defined in 6111 * RFC2960 [5] section 8.1 and 8.2. 6112 */ 6113 if (transport) 6114 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6115 SCTP_TRANSPORT(transport)); 6116 6117 /* Reconfig T4 timer and transport. */ 6118 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6119 6120 /* ADDIP 4.1 B2) Increment the association error counters and perform 6121 * endpoint failure detection on the association as defined in 6122 * RFC2960 [5] section 8.1 and 8.2. 6123 * association error counter is incremented in SCTP_CMD_STRIKE. 6124 */ 6125 if (asoc->overall_error_count >= asoc->max_retrans) { 6126 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6127 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6128 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6129 SCTP_ERROR(ETIMEDOUT)); 6130 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6131 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6132 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6133 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6134 return SCTP_DISPOSITION_ABORT; 6135 } 6136 6137 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6138 * the ASCONF chunk was sent by doubling the RTO timer value. 6139 * This is done in SCTP_CMD_STRIKE. 6140 */ 6141 6142 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6143 * choose an alternate destination address (please refer to RFC2960 6144 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6145 * chunk, it MUST be the same (including its serial number) as the last 6146 * ASCONF sent. 6147 */ 6148 sctp_chunk_hold(asoc->addip_last_asconf); 6149 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6150 SCTP_CHUNK(asoc->addip_last_asconf)); 6151 6152 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6153 * destination is selected, then the RTO used will be that of the new 6154 * destination address. 6155 */ 6156 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6157 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6158 6159 return SCTP_DISPOSITION_CONSUME; 6160 } 6161 6162 /* sctpimpguide-05 Section 2.12.2 6163 * The sender of the SHUTDOWN MAY also start an overall guard timer 6164 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6165 * At the expiration of this timer the sender SHOULD abort the association 6166 * by sending an ABORT chunk. 6167 */ 6168 enum sctp_disposition sctp_sf_t5_timer_expire( 6169 struct net *net, 6170 const struct sctp_endpoint *ep, 6171 const struct sctp_association *asoc, 6172 const union sctp_subtype type, 6173 void *arg, 6174 struct sctp_cmd_seq *commands) 6175 { 6176 struct sctp_chunk *reply = NULL; 6177 6178 pr_debug("%s: timer T5 expired\n", __func__); 6179 6180 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6181 6182 reply = sctp_make_abort(asoc, NULL, 0); 6183 if (!reply) 6184 goto nomem; 6185 6186 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6187 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6188 SCTP_ERROR(ETIMEDOUT)); 6189 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6190 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6191 6192 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6193 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6194 6195 return SCTP_DISPOSITION_DELETE_TCB; 6196 nomem: 6197 return SCTP_DISPOSITION_NOMEM; 6198 } 6199 6200 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6201 * the association is automatically closed by starting the shutdown process. 6202 * The work that needs to be done is same as when SHUTDOWN is initiated by 6203 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6204 */ 6205 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6206 struct net *net, 6207 const struct sctp_endpoint *ep, 6208 const struct sctp_association *asoc, 6209 const union sctp_subtype type, 6210 void *arg, 6211 struct sctp_cmd_seq *commands) 6212 { 6213 enum sctp_disposition disposition; 6214 6215 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6216 6217 /* From 9.2 Shutdown of an Association 6218 * Upon receipt of the SHUTDOWN primitive from its upper 6219 * layer, the endpoint enters SHUTDOWN-PENDING state and 6220 * remains there until all outstanding data has been 6221 * acknowledged by its peer. The endpoint accepts no new data 6222 * from its upper layer, but retransmits data to the far end 6223 * if necessary to fill gaps. 6224 */ 6225 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6226 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6227 6228 disposition = SCTP_DISPOSITION_CONSUME; 6229 if (sctp_outq_is_empty(&asoc->outqueue)) { 6230 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6231 NULL, commands); 6232 } 6233 6234 return disposition; 6235 } 6236 6237 /***************************************************************************** 6238 * These are sa state functions which could apply to all types of events. 6239 ****************************************************************************/ 6240 6241 /* 6242 * This table entry is not implemented. 6243 * 6244 * Inputs 6245 * (endpoint, asoc, chunk) 6246 * 6247 * The return value is the disposition of the chunk. 6248 */ 6249 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6250 const struct sctp_endpoint *ep, 6251 const struct sctp_association *asoc, 6252 const union sctp_subtype type, 6253 void *arg, struct sctp_cmd_seq *commands) 6254 { 6255 return SCTP_DISPOSITION_NOT_IMPL; 6256 } 6257 6258 /* 6259 * This table entry represents a bug. 6260 * 6261 * Inputs 6262 * (endpoint, asoc, chunk) 6263 * 6264 * The return value is the disposition of the chunk. 6265 */ 6266 enum sctp_disposition sctp_sf_bug(struct net *net, 6267 const struct sctp_endpoint *ep, 6268 const struct sctp_association *asoc, 6269 const union sctp_subtype type, 6270 void *arg, struct sctp_cmd_seq *commands) 6271 { 6272 return SCTP_DISPOSITION_BUG; 6273 } 6274 6275 /* 6276 * This table entry represents the firing of a timer in the wrong state. 6277 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6278 * when the association is in the wrong state. This event should 6279 * be ignored, so as to prevent any rearming of the timer. 6280 * 6281 * Inputs 6282 * (endpoint, asoc, chunk) 6283 * 6284 * The return value is the disposition of the chunk. 6285 */ 6286 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6287 const struct sctp_endpoint *ep, 6288 const struct sctp_association *asoc, 6289 const union sctp_subtype type, 6290 void *arg, 6291 struct sctp_cmd_seq *commands) 6292 { 6293 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6294 6295 return SCTP_DISPOSITION_CONSUME; 6296 } 6297 6298 /******************************************************************** 6299 * 2nd Level Abstractions 6300 ********************************************************************/ 6301 6302 /* Pull the SACK chunk based on the SACK header. */ 6303 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6304 { 6305 struct sctp_sackhdr *sack; 6306 __u16 num_dup_tsns; 6307 unsigned int len; 6308 __u16 num_blocks; 6309 6310 /* Protect ourselves from reading too far into 6311 * the skb from a bogus sender. 6312 */ 6313 sack = (struct sctp_sackhdr *) chunk->skb->data; 6314 6315 num_blocks = ntohs(sack->num_gap_ack_blocks); 6316 num_dup_tsns = ntohs(sack->num_dup_tsns); 6317 len = sizeof(struct sctp_sackhdr); 6318 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6319 if (len > chunk->skb->len) 6320 return NULL; 6321 6322 skb_pull(chunk->skb, len); 6323 6324 return sack; 6325 } 6326 6327 /* Create an ABORT packet to be sent as a response, with the specified 6328 * error causes. 6329 */ 6330 static struct sctp_packet *sctp_abort_pkt_new( 6331 struct net *net, 6332 const struct sctp_endpoint *ep, 6333 const struct sctp_association *asoc, 6334 struct sctp_chunk *chunk, 6335 const void *payload, size_t paylen) 6336 { 6337 struct sctp_packet *packet; 6338 struct sctp_chunk *abort; 6339 6340 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6341 6342 if (packet) { 6343 /* Make an ABORT. 6344 * The T bit will be set if the asoc is NULL. 6345 */ 6346 abort = sctp_make_abort(asoc, chunk, paylen); 6347 if (!abort) { 6348 sctp_ootb_pkt_free(packet); 6349 return NULL; 6350 } 6351 6352 /* Reflect vtag if T-Bit is set */ 6353 if (sctp_test_T_bit(abort)) 6354 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6355 6356 /* Add specified error causes, i.e., payload, to the 6357 * end of the chunk. 6358 */ 6359 sctp_addto_chunk(abort, paylen, payload); 6360 6361 /* Set the skb to the belonging sock for accounting. */ 6362 abort->skb->sk = ep->base.sk; 6363 6364 sctp_packet_append_chunk(packet, abort); 6365 6366 } 6367 6368 return packet; 6369 } 6370 6371 /* Allocate a packet for responding in the OOTB conditions. */ 6372 static struct sctp_packet *sctp_ootb_pkt_new( 6373 struct net *net, 6374 const struct sctp_association *asoc, 6375 const struct sctp_chunk *chunk) 6376 { 6377 struct sctp_transport *transport; 6378 struct sctp_packet *packet; 6379 __u16 sport, dport; 6380 __u32 vtag; 6381 6382 /* Get the source and destination port from the inbound packet. */ 6383 sport = ntohs(chunk->sctp_hdr->dest); 6384 dport = ntohs(chunk->sctp_hdr->source); 6385 6386 /* The V-tag is going to be the same as the inbound packet if no 6387 * association exists, otherwise, use the peer's vtag. 6388 */ 6389 if (asoc) { 6390 /* Special case the INIT-ACK as there is no peer's vtag 6391 * yet. 6392 */ 6393 switch (chunk->chunk_hdr->type) { 6394 case SCTP_CID_INIT: 6395 case SCTP_CID_INIT_ACK: 6396 { 6397 struct sctp_initack_chunk *initack; 6398 6399 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6400 vtag = ntohl(initack->init_hdr.init_tag); 6401 break; 6402 } 6403 default: 6404 vtag = asoc->peer.i.init_tag; 6405 break; 6406 } 6407 } else { 6408 /* Special case the INIT and stale COOKIE_ECHO as there is no 6409 * vtag yet. 6410 */ 6411 switch (chunk->chunk_hdr->type) { 6412 case SCTP_CID_INIT: 6413 { 6414 struct sctp_init_chunk *init; 6415 6416 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6417 vtag = ntohl(init->init_hdr.init_tag); 6418 break; 6419 } 6420 default: 6421 vtag = ntohl(chunk->sctp_hdr->vtag); 6422 break; 6423 } 6424 } 6425 6426 /* Make a transport for the bucket, Eliza... */ 6427 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6428 if (!transport) 6429 goto nomem; 6430 6431 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6432 6433 /* Cache a route for the transport with the chunk's destination as 6434 * the source address. 6435 */ 6436 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6437 sctp_sk(net->sctp.ctl_sock)); 6438 6439 packet = &transport->packet; 6440 sctp_packet_init(packet, transport, sport, dport); 6441 sctp_packet_config(packet, vtag, 0); 6442 6443 return packet; 6444 6445 nomem: 6446 return NULL; 6447 } 6448 6449 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6450 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6451 { 6452 sctp_transport_free(packet->transport); 6453 } 6454 6455 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6456 static void sctp_send_stale_cookie_err(struct net *net, 6457 const struct sctp_endpoint *ep, 6458 const struct sctp_association *asoc, 6459 const struct sctp_chunk *chunk, 6460 struct sctp_cmd_seq *commands, 6461 struct sctp_chunk *err_chunk) 6462 { 6463 struct sctp_packet *packet; 6464 6465 if (err_chunk) { 6466 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6467 if (packet) { 6468 struct sctp_signed_cookie *cookie; 6469 6470 /* Override the OOTB vtag from the cookie. */ 6471 cookie = chunk->subh.cookie_hdr; 6472 packet->vtag = cookie->c.peer_vtag; 6473 6474 /* Set the skb to the belonging sock for accounting. */ 6475 err_chunk->skb->sk = ep->base.sk; 6476 sctp_packet_append_chunk(packet, err_chunk); 6477 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6478 SCTP_PACKET(packet)); 6479 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6480 } else 6481 sctp_chunk_free (err_chunk); 6482 } 6483 } 6484 6485 6486 /* Process a data chunk */ 6487 static int sctp_eat_data(const struct sctp_association *asoc, 6488 struct sctp_chunk *chunk, 6489 struct sctp_cmd_seq *commands) 6490 { 6491 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6492 struct sock *sk = asoc->base.sk; 6493 struct net *net = sock_net(sk); 6494 struct sctp_datahdr *data_hdr; 6495 struct sctp_chunk *err; 6496 enum sctp_verb deliver; 6497 size_t datalen; 6498 __u32 tsn; 6499 int tmp; 6500 6501 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6502 chunk->subh.data_hdr = data_hdr; 6503 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6504 6505 tsn = ntohl(data_hdr->tsn); 6506 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6507 6508 /* ASSERT: Now skb->data is really the user data. */ 6509 6510 /* Process ECN based congestion. 6511 * 6512 * Since the chunk structure is reused for all chunks within 6513 * a packet, we use ecn_ce_done to track if we've already 6514 * done CE processing for this packet. 6515 * 6516 * We need to do ECN processing even if we plan to discard the 6517 * chunk later. 6518 */ 6519 6520 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6521 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6522 chunk->ecn_ce_done = 1; 6523 6524 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6525 /* Do real work as side effect. */ 6526 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6527 SCTP_U32(tsn)); 6528 } 6529 } 6530 6531 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6532 if (tmp < 0) { 6533 /* The TSN is too high--silently discard the chunk and 6534 * count on it getting retransmitted later. 6535 */ 6536 if (chunk->asoc) 6537 chunk->asoc->stats.outofseqtsns++; 6538 return SCTP_IERROR_HIGH_TSN; 6539 } else if (tmp > 0) { 6540 /* This is a duplicate. Record it. */ 6541 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6542 return SCTP_IERROR_DUP_TSN; 6543 } 6544 6545 /* This is a new TSN. */ 6546 6547 /* Discard if there is no room in the receive window. 6548 * Actually, allow a little bit of overflow (up to a MTU). 6549 */ 6550 datalen = ntohs(chunk->chunk_hdr->length); 6551 datalen -= sctp_datachk_len(&asoc->stream); 6552 6553 deliver = SCTP_CMD_CHUNK_ULP; 6554 6555 /* Think about partial delivery. */ 6556 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6557 6558 /* Even if we don't accept this chunk there is 6559 * memory pressure. 6560 */ 6561 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6562 } 6563 6564 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6565 * seems a bit troublesome in that frag_point varies based on 6566 * PMTU. In cases, such as loopback, this might be a rather 6567 * large spill over. 6568 */ 6569 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6570 (datalen > asoc->rwnd + asoc->frag_point))) { 6571 6572 /* If this is the next TSN, consider reneging to make 6573 * room. Note: Playing nice with a confused sender. A 6574 * malicious sender can still eat up all our buffer 6575 * space and in the future we may want to detect and 6576 * do more drastic reneging. 6577 */ 6578 if (sctp_tsnmap_has_gap(map) && 6579 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6580 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6581 deliver = SCTP_CMD_RENEGE; 6582 } else { 6583 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6584 __func__, tsn, datalen, asoc->rwnd); 6585 6586 return SCTP_IERROR_IGNORE_TSN; 6587 } 6588 } 6589 6590 /* 6591 * Also try to renege to limit our memory usage in the event that 6592 * we are under memory pressure 6593 * If we can't renege, don't worry about it, the sk_rmem_schedule 6594 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6595 * memory usage too much 6596 */ 6597 if (sk_under_memory_pressure(sk)) { 6598 if (sctp_tsnmap_has_gap(map) && 6599 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6600 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6601 __func__, tsn); 6602 deliver = SCTP_CMD_RENEGE; 6603 } 6604 } 6605 6606 /* 6607 * Section 3.3.10.9 No User Data (9) 6608 * 6609 * Cause of error 6610 * --------------- 6611 * No User Data: This error cause is returned to the originator of a 6612 * DATA chunk if a received DATA chunk has no user data. 6613 */ 6614 if (unlikely(0 == datalen)) { 6615 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6616 if (err) { 6617 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6618 SCTP_CHUNK(err)); 6619 } 6620 /* We are going to ABORT, so we might as well stop 6621 * processing the rest of the chunks in the packet. 6622 */ 6623 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6624 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6625 SCTP_ERROR(ECONNABORTED)); 6626 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6627 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6628 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6629 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6630 return SCTP_IERROR_NO_DATA; 6631 } 6632 6633 chunk->data_accepted = 1; 6634 6635 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6636 * if we renege and the chunk arrives again. 6637 */ 6638 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6639 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6640 if (chunk->asoc) 6641 chunk->asoc->stats.iuodchunks++; 6642 } else { 6643 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6644 if (chunk->asoc) 6645 chunk->asoc->stats.iodchunks++; 6646 } 6647 6648 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6649 * 6650 * If an endpoint receive a DATA chunk with an invalid stream 6651 * identifier, it shall acknowledge the reception of the DATA chunk 6652 * following the normal procedure, immediately send an ERROR chunk 6653 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6654 * and discard the DATA chunk. 6655 */ 6656 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6657 /* Mark tsn as received even though we drop it */ 6658 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6659 6660 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6661 &data_hdr->stream, 6662 sizeof(data_hdr->stream), 6663 sizeof(u16)); 6664 if (err) 6665 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6666 SCTP_CHUNK(err)); 6667 return SCTP_IERROR_BAD_STREAM; 6668 } 6669 6670 /* Check to see if the SSN is possible for this TSN. 6671 * The biggest gap we can record is 4K wide. Since SSNs wrap 6672 * at an unsigned short, there is no way that an SSN can 6673 * wrap and for a valid TSN. We can simply check if the current 6674 * SSN is smaller then the next expected one. If it is, it wrapped 6675 * and is invalid. 6676 */ 6677 if (!asoc->stream.si->validate_data(chunk)) 6678 return SCTP_IERROR_PROTO_VIOLATION; 6679 6680 /* Send the data up to the user. Note: Schedule the 6681 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6682 * chunk needs the updated rwnd. 6683 */ 6684 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6685 6686 return SCTP_IERROR_NO_ERROR; 6687 } 6688