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