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 simultaneous 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 simultaneous 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 simultaneous 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 static int sctp_sf_do_assoc_update(struct sctp_association *asoc, 1777 struct sctp_association *new, 1778 struct sctp_cmd_seq *cmds) 1779 { 1780 struct net *net = asoc->base.net; 1781 struct sctp_chunk *abort; 1782 1783 if (!sctp_assoc_update(asoc, new)) 1784 return 0; 1785 1786 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr)); 1787 if (abort) { 1788 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 1789 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 1790 } 1791 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED)); 1792 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED, 1793 SCTP_PERR(SCTP_ERROR_RSRC_LOW)); 1794 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1795 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1796 1797 return -ENOMEM; 1798 } 1799 1800 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1801 * 1802 * Section 5.2.4 1803 * A) In this case, the peer may have restarted. 1804 */ 1805 static enum sctp_disposition sctp_sf_do_dupcook_a( 1806 struct net *net, 1807 const struct sctp_endpoint *ep, 1808 const struct sctp_association *asoc, 1809 struct sctp_chunk *chunk, 1810 struct sctp_cmd_seq *commands, 1811 struct sctp_association *new_asoc) 1812 { 1813 struct sctp_init_chunk *peer_init; 1814 enum sctp_disposition disposition; 1815 struct sctp_ulpevent *ev; 1816 struct sctp_chunk *repl; 1817 struct sctp_chunk *err; 1818 1819 /* new_asoc is a brand-new association, so these are not yet 1820 * side effects--it is safe to run them here. 1821 */ 1822 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1823 1824 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1825 GFP_ATOMIC)) 1826 goto nomem; 1827 1828 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1829 goto nomem; 1830 1831 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1832 return SCTP_DISPOSITION_DISCARD; 1833 1834 /* Make sure no new addresses are being added during the 1835 * restart. Though this is a pretty complicated attack 1836 * since you'd have to get inside the cookie. 1837 */ 1838 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1839 return SCTP_DISPOSITION_CONSUME; 1840 1841 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1842 * the peer has restarted (Action A), it MUST NOT setup a new 1843 * association but instead resend the SHUTDOWN ACK and send an ERROR 1844 * chunk with a "Cookie Received while Shutting Down" error cause to 1845 * its peer. 1846 */ 1847 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1848 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1849 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1850 chunk, commands); 1851 if (SCTP_DISPOSITION_NOMEM == disposition) 1852 goto nomem; 1853 1854 err = sctp_make_op_error(asoc, chunk, 1855 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1856 NULL, 0, 0); 1857 if (err) 1858 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1859 SCTP_CHUNK(err)); 1860 1861 return SCTP_DISPOSITION_CONSUME; 1862 } 1863 1864 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1865 * data. Consider the optional choice of resending of this data. 1866 */ 1867 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1868 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1869 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1870 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1871 1872 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1873 * and ASCONF-ACK cache. 1874 */ 1875 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1876 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1877 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1878 1879 /* Update the content of current association. */ 1880 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1881 goto nomem; 1882 1883 repl = sctp_make_cookie_ack(asoc, chunk); 1884 if (!repl) 1885 goto nomem; 1886 1887 /* Report association restart to upper layer. */ 1888 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1889 asoc->c.sinit_num_ostreams, 1890 asoc->c.sinit_max_instreams, 1891 NULL, GFP_ATOMIC); 1892 if (!ev) 1893 goto nomem_ev; 1894 1895 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1896 if ((sctp_state(asoc, SHUTDOWN_PENDING) || 1897 sctp_state(asoc, SHUTDOWN_SENT)) && 1898 (sctp_sstate(asoc->base.sk, CLOSING) || 1899 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1900 /* If the socket has been closed by user, don't 1901 * transition to ESTABLISHED. Instead trigger SHUTDOWN 1902 * bundled with COOKIE_ACK. 1903 */ 1904 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1905 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1906 SCTP_ST_CHUNK(0), repl, 1907 commands); 1908 } else { 1909 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1910 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1911 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1912 } 1913 return SCTP_DISPOSITION_CONSUME; 1914 1915 nomem_ev: 1916 sctp_chunk_free(repl); 1917 nomem: 1918 return SCTP_DISPOSITION_NOMEM; 1919 } 1920 1921 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1922 * 1923 * Section 5.2.4 1924 * B) In this case, both sides may be attempting to start an association 1925 * at about the same time but the peer endpoint started its INIT 1926 * after responding to the local endpoint's INIT 1927 */ 1928 /* This case represents an initialization collision. */ 1929 static enum sctp_disposition sctp_sf_do_dupcook_b( 1930 struct net *net, 1931 const struct sctp_endpoint *ep, 1932 const struct sctp_association *asoc, 1933 struct sctp_chunk *chunk, 1934 struct sctp_cmd_seq *commands, 1935 struct sctp_association *new_asoc) 1936 { 1937 struct sctp_init_chunk *peer_init; 1938 struct sctp_chunk *repl; 1939 1940 /* new_asoc is a brand-new association, so these are not yet 1941 * side effects--it is safe to run them here. 1942 */ 1943 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1944 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1945 GFP_ATOMIC)) 1946 goto nomem; 1947 1948 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1949 goto nomem; 1950 1951 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1952 return SCTP_DISPOSITION_DISCARD; 1953 1954 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1955 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1956 if (asoc->state < SCTP_STATE_ESTABLISHED) 1957 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1958 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1959 1960 /* Update the content of current association. */ 1961 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1962 goto nomem; 1963 1964 repl = sctp_make_cookie_ack(asoc, chunk); 1965 if (!repl) 1966 goto nomem; 1967 1968 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1969 1970 /* RFC 2960 5.1 Normal Establishment of an Association 1971 * 1972 * D) IMPLEMENTATION NOTE: An implementation may choose to 1973 * send the Communication Up notification to the SCTP user 1974 * upon reception of a valid COOKIE ECHO chunk. 1975 * 1976 * Sadly, this needs to be implemented as a side-effect, because 1977 * we are not guaranteed to have set the association id of the real 1978 * association and so these notifications need to be delayed until 1979 * the association id is allocated. 1980 */ 1981 1982 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1983 1984 /* Sockets API Draft Section 5.3.1.6 1985 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1986 * delivers this notification to inform the application that of the 1987 * peers requested adaptation layer. 1988 * 1989 * This also needs to be done as a side effect for the same reason as 1990 * above. 1991 */ 1992 if (asoc->peer.adaptation_ind) 1993 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1994 1995 if (!asoc->peer.auth_capable) 1996 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 1997 1998 return SCTP_DISPOSITION_CONSUME; 1999 2000 nomem: 2001 return SCTP_DISPOSITION_NOMEM; 2002 } 2003 2004 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 2005 * 2006 * Section 5.2.4 2007 * C) In this case, the local endpoint's cookie has arrived late. 2008 * Before it arrived, the local endpoint sent an INIT and received an 2009 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 2010 * but a new tag of its own. 2011 */ 2012 /* This case represents an initialization collision. */ 2013 static enum sctp_disposition sctp_sf_do_dupcook_c( 2014 struct net *net, 2015 const struct sctp_endpoint *ep, 2016 const struct sctp_association *asoc, 2017 struct sctp_chunk *chunk, 2018 struct sctp_cmd_seq *commands, 2019 struct sctp_association *new_asoc) 2020 { 2021 /* The cookie should be silently discarded. 2022 * The endpoint SHOULD NOT change states and should leave 2023 * any timers running. 2024 */ 2025 return SCTP_DISPOSITION_DISCARD; 2026 } 2027 2028 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 2029 * 2030 * Section 5.2.4 2031 * 2032 * D) When both local and remote tags match the endpoint should always 2033 * enter the ESTABLISHED state, if it has not already done so. 2034 */ 2035 /* This case represents an initialization collision. */ 2036 static enum sctp_disposition sctp_sf_do_dupcook_d( 2037 struct net *net, 2038 const struct sctp_endpoint *ep, 2039 const struct sctp_association *asoc, 2040 struct sctp_chunk *chunk, 2041 struct sctp_cmd_seq *commands, 2042 struct sctp_association *new_asoc) 2043 { 2044 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2045 struct sctp_chunk *repl; 2046 2047 /* Clarification from Implementor's Guide: 2048 * D) When both local and remote tags match the endpoint should 2049 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2050 * It should stop any cookie timer that may be running and send 2051 * a COOKIE ACK. 2052 */ 2053 2054 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2055 return SCTP_DISPOSITION_DISCARD; 2056 2057 /* Don't accidentally move back into established state. */ 2058 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2059 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2060 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2061 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2062 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2063 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2064 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2065 SCTP_NULL()); 2066 2067 /* RFC 2960 5.1 Normal Establishment of an Association 2068 * 2069 * D) IMPLEMENTATION NOTE: An implementation may choose 2070 * to send the Communication Up notification to the 2071 * SCTP user upon reception of a valid COOKIE 2072 * ECHO chunk. 2073 */ 2074 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2075 SCTP_COMM_UP, 0, 2076 asoc->c.sinit_num_ostreams, 2077 asoc->c.sinit_max_instreams, 2078 NULL, GFP_ATOMIC); 2079 if (!ev) 2080 goto nomem; 2081 2082 /* Sockets API Draft Section 5.3.1.6 2083 * When a peer sends a Adaptation Layer Indication parameter, 2084 * SCTP delivers this notification to inform the application 2085 * that of the peers requested adaptation layer. 2086 */ 2087 if (asoc->peer.adaptation_ind) { 2088 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2089 GFP_ATOMIC); 2090 if (!ai_ev) 2091 goto nomem; 2092 2093 } 2094 2095 if (!asoc->peer.auth_capable) { 2096 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2097 SCTP_AUTH_NO_AUTH, 2098 GFP_ATOMIC); 2099 if (!auth_ev) 2100 goto nomem; 2101 } 2102 } 2103 2104 repl = sctp_make_cookie_ack(asoc, chunk); 2105 if (!repl) 2106 goto nomem; 2107 2108 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2109 2110 if (ev) 2111 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2112 SCTP_ULPEVENT(ev)); 2113 if (ai_ev) 2114 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2115 SCTP_ULPEVENT(ai_ev)); 2116 if (auth_ev) 2117 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2118 SCTP_ULPEVENT(auth_ev)); 2119 2120 return SCTP_DISPOSITION_CONSUME; 2121 2122 nomem: 2123 if (auth_ev) 2124 sctp_ulpevent_free(auth_ev); 2125 if (ai_ev) 2126 sctp_ulpevent_free(ai_ev); 2127 if (ev) 2128 sctp_ulpevent_free(ev); 2129 return SCTP_DISPOSITION_NOMEM; 2130 } 2131 2132 /* 2133 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2134 * chunk was retransmitted and then delayed in the network. 2135 * 2136 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2137 * 2138 * Verification Tag: None. Do cookie validation. 2139 * 2140 * Inputs 2141 * (endpoint, asoc, chunk) 2142 * 2143 * Outputs 2144 * (asoc, reply_msg, msg_up, timers, counters) 2145 * 2146 * The return value is the disposition of the chunk. 2147 */ 2148 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2149 struct net *net, 2150 const struct sctp_endpoint *ep, 2151 const struct sctp_association *asoc, 2152 const union sctp_subtype type, 2153 void *arg, 2154 struct sctp_cmd_seq *commands) 2155 { 2156 struct sctp_association *new_asoc; 2157 struct sctp_chunk *chunk = arg; 2158 enum sctp_disposition retval; 2159 struct sctp_chunk *err_chk_p; 2160 int error = 0; 2161 char action; 2162 2163 /* Make sure that the chunk has a valid length from the protocol 2164 * perspective. In this case check to make sure we have at least 2165 * enough for the chunk header. Cookie length verification is 2166 * done later. 2167 */ 2168 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2169 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2170 commands); 2171 2172 /* "Decode" the chunk. We have no optional parameters so we 2173 * are in good shape. 2174 */ 2175 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2176 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2177 sizeof(struct sctp_chunkhdr))) 2178 goto nomem; 2179 2180 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2181 * of a duplicate COOKIE ECHO match the Verification Tags of the 2182 * current association, consider the State Cookie valid even if 2183 * the lifespan is exceeded. 2184 */ 2185 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2186 &err_chk_p); 2187 2188 /* FIXME: 2189 * If the re-build failed, what is the proper error path 2190 * from here? 2191 * 2192 * [We should abort the association. --piggy] 2193 */ 2194 if (!new_asoc) { 2195 /* FIXME: Several errors are possible. A bad cookie should 2196 * be silently discarded, but think about logging it too. 2197 */ 2198 switch (error) { 2199 case -SCTP_IERROR_NOMEM: 2200 goto nomem; 2201 2202 case -SCTP_IERROR_STALE_COOKIE: 2203 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2204 err_chk_p); 2205 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2206 case -SCTP_IERROR_BAD_SIG: 2207 default: 2208 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2209 } 2210 } 2211 2212 /* Update socket peer label if first association. */ 2213 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 2214 chunk->skb)) { 2215 sctp_association_free(new_asoc); 2216 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2217 } 2218 2219 /* Set temp so that it won't be added into hashtable */ 2220 new_asoc->temp = 1; 2221 2222 /* Compare the tie_tag in cookie with the verification tag of 2223 * current association. 2224 */ 2225 action = sctp_tietags_compare(new_asoc, asoc); 2226 2227 switch (action) { 2228 case 'A': /* Association restart. */ 2229 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2230 new_asoc); 2231 break; 2232 2233 case 'B': /* Collision case B. */ 2234 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2235 new_asoc); 2236 break; 2237 2238 case 'C': /* Collision case C. */ 2239 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2240 new_asoc); 2241 break; 2242 2243 case 'D': /* Collision case D. */ 2244 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2245 new_asoc); 2246 break; 2247 2248 default: /* Discard packet for all others. */ 2249 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2250 break; 2251 } 2252 2253 /* Delete the temporary new association. */ 2254 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2255 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2256 2257 /* Restore association pointer to provide SCTP command interpreter 2258 * with a valid context in case it needs to manipulate 2259 * the queues */ 2260 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2261 SCTP_ASOC((struct sctp_association *)asoc)); 2262 2263 return retval; 2264 2265 nomem: 2266 return SCTP_DISPOSITION_NOMEM; 2267 } 2268 2269 /* 2270 * Process an ABORT. (SHUTDOWN-PENDING state) 2271 * 2272 * See sctp_sf_do_9_1_abort(). 2273 */ 2274 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2275 struct net *net, 2276 const struct sctp_endpoint *ep, 2277 const struct sctp_association *asoc, 2278 const union sctp_subtype type, 2279 void *arg, 2280 struct sctp_cmd_seq *commands) 2281 { 2282 struct sctp_chunk *chunk = arg; 2283 2284 if (!sctp_vtag_verify_either(chunk, asoc)) 2285 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2286 2287 /* Make sure that the ABORT chunk has a valid length. 2288 * Since this is an ABORT chunk, we have to discard it 2289 * because of the following text: 2290 * RFC 2960, Section 3.3.7 2291 * If an endpoint receives an ABORT with a format error or for an 2292 * association that doesn't exist, it MUST silently discard it. 2293 * Because the length is "invalid", we can't really discard just 2294 * as we do not know its true length. So, to be safe, discard the 2295 * packet. 2296 */ 2297 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2298 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2299 2300 /* ADD-IP: Special case for ABORT chunks 2301 * F4) One special consideration is that ABORT Chunks arriving 2302 * destined to the IP address being deleted MUST be 2303 * ignored (see Section 5.3.1 for further details). 2304 */ 2305 if (SCTP_ADDR_DEL == 2306 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2307 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2308 2309 if (!sctp_err_chunk_valid(chunk)) 2310 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2311 2312 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2313 } 2314 2315 /* 2316 * Process an ABORT. (SHUTDOWN-SENT state) 2317 * 2318 * See sctp_sf_do_9_1_abort(). 2319 */ 2320 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2321 struct net *net, 2322 const struct sctp_endpoint *ep, 2323 const struct sctp_association *asoc, 2324 const union sctp_subtype type, 2325 void *arg, 2326 struct sctp_cmd_seq *commands) 2327 { 2328 struct sctp_chunk *chunk = arg; 2329 2330 if (!sctp_vtag_verify_either(chunk, asoc)) 2331 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2332 2333 /* Make sure that the ABORT chunk has a valid length. 2334 * Since this is an ABORT chunk, we have to discard it 2335 * because of the following text: 2336 * RFC 2960, Section 3.3.7 2337 * If an endpoint receives an ABORT with a format error or for an 2338 * association that doesn't exist, it MUST silently discard it. 2339 * Because the length is "invalid", we can't really discard just 2340 * as we do not know its true length. So, to be safe, discard the 2341 * packet. 2342 */ 2343 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2344 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2345 2346 /* ADD-IP: Special case for ABORT chunks 2347 * F4) One special consideration is that ABORT Chunks arriving 2348 * destined to the IP address being deleted MUST be 2349 * ignored (see Section 5.3.1 for further details). 2350 */ 2351 if (SCTP_ADDR_DEL == 2352 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2353 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2354 2355 if (!sctp_err_chunk_valid(chunk)) 2356 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2357 2358 /* Stop the T2-shutdown timer. */ 2359 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2360 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2361 2362 /* Stop the T5-shutdown guard timer. */ 2363 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2364 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2365 2366 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2367 } 2368 2369 /* 2370 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2371 * 2372 * See sctp_sf_do_9_1_abort(). 2373 */ 2374 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2375 struct net *net, 2376 const struct sctp_endpoint *ep, 2377 const struct sctp_association *asoc, 2378 const union sctp_subtype type, 2379 void *arg, 2380 struct sctp_cmd_seq *commands) 2381 { 2382 /* The same T2 timer, so we should be able to use 2383 * common function with the SHUTDOWN-SENT state. 2384 */ 2385 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2386 } 2387 2388 /* 2389 * Handle an Error received in COOKIE_ECHOED state. 2390 * 2391 * Only handle the error type of stale COOKIE Error, the other errors will 2392 * be ignored. 2393 * 2394 * Inputs 2395 * (endpoint, asoc, chunk) 2396 * 2397 * Outputs 2398 * (asoc, reply_msg, msg_up, timers, counters) 2399 * 2400 * The return value is the disposition of the chunk. 2401 */ 2402 enum sctp_disposition sctp_sf_cookie_echoed_err( 2403 struct net *net, 2404 const struct sctp_endpoint *ep, 2405 const struct sctp_association *asoc, 2406 const union sctp_subtype type, 2407 void *arg, 2408 struct sctp_cmd_seq *commands) 2409 { 2410 struct sctp_chunk *chunk = arg; 2411 struct sctp_errhdr *err; 2412 2413 if (!sctp_vtag_verify(chunk, asoc)) 2414 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2415 2416 /* Make sure that the ERROR chunk has a valid length. 2417 * The parameter walking depends on this as well. 2418 */ 2419 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2420 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2421 commands); 2422 2423 /* Process the error here */ 2424 /* FUTURE FIXME: When PR-SCTP related and other optional 2425 * parms are emitted, this will have to change to handle multiple 2426 * errors. 2427 */ 2428 sctp_walk_errors(err, chunk->chunk_hdr) { 2429 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2430 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2431 arg, commands); 2432 } 2433 2434 /* It is possible to have malformed error causes, and that 2435 * will cause us to end the walk early. However, since 2436 * we are discarding the packet, there should be no adverse 2437 * affects. 2438 */ 2439 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2440 } 2441 2442 /* 2443 * Handle a Stale COOKIE Error 2444 * 2445 * Section: 5.2.6 Handle Stale COOKIE Error 2446 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2447 * one of the following three alternatives. 2448 * ... 2449 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2450 * Preservative parameter requesting an extension to the lifetime of 2451 * the State Cookie. When calculating the time extension, an 2452 * implementation SHOULD use the RTT information measured based on the 2453 * previous COOKIE ECHO / ERROR exchange, and should add no more 2454 * than 1 second beyond the measured RTT, due to long State Cookie 2455 * lifetimes making the endpoint more subject to a replay attack. 2456 * 2457 * Verification Tag: Not explicit, but safe to ignore. 2458 * 2459 * Inputs 2460 * (endpoint, asoc, chunk) 2461 * 2462 * Outputs 2463 * (asoc, reply_msg, msg_up, timers, counters) 2464 * 2465 * The return value is the disposition of the chunk. 2466 */ 2467 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2468 struct net *net, 2469 const struct sctp_endpoint *ep, 2470 const struct sctp_association *asoc, 2471 const union sctp_subtype type, 2472 void *arg, 2473 struct sctp_cmd_seq *commands) 2474 { 2475 int attempts = asoc->init_err_counter + 1; 2476 struct sctp_chunk *chunk = arg, *reply; 2477 struct sctp_cookie_preserve_param bht; 2478 struct sctp_bind_addr *bp; 2479 struct sctp_errhdr *err; 2480 u32 stale; 2481 2482 if (attempts > asoc->max_init_attempts) { 2483 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2484 SCTP_ERROR(ETIMEDOUT)); 2485 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2486 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2487 return SCTP_DISPOSITION_DELETE_TCB; 2488 } 2489 2490 err = (struct sctp_errhdr *)(chunk->skb->data); 2491 2492 /* When calculating the time extension, an implementation 2493 * SHOULD use the RTT information measured based on the 2494 * previous COOKIE ECHO / ERROR exchange, and should add no 2495 * more than 1 second beyond the measured RTT, due to long 2496 * State Cookie lifetimes making the endpoint more subject to 2497 * a replay attack. 2498 * Measure of Staleness's unit is usec. (1/1000000 sec) 2499 * Suggested Cookie Life-span Increment's unit is msec. 2500 * (1/1000 sec) 2501 * In general, if you use the suggested cookie life, the value 2502 * found in the field of measure of staleness should be doubled 2503 * to give ample time to retransmit the new cookie and thus 2504 * yield a higher probability of success on the reattempt. 2505 */ 2506 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2507 stale = (stale * 2) / 1000; 2508 2509 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2510 bht.param_hdr.length = htons(sizeof(bht)); 2511 bht.lifespan_increment = htonl(stale); 2512 2513 /* Build that new INIT chunk. */ 2514 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2515 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2516 if (!reply) 2517 goto nomem; 2518 2519 sctp_addto_chunk(reply, sizeof(bht), &bht); 2520 2521 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2522 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2523 2524 /* Stop pending T3-rtx and heartbeat timers */ 2525 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2526 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2527 2528 /* Delete non-primary peer ip addresses since we are transitioning 2529 * back to the COOKIE-WAIT state 2530 */ 2531 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2532 2533 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2534 * resend 2535 */ 2536 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2537 SCTP_TRANSPORT(asoc->peer.primary_path)); 2538 2539 /* Cast away the const modifier, as we want to just 2540 * rerun it through as a sideffect. 2541 */ 2542 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2543 2544 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2545 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2546 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2547 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2548 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2549 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2550 2551 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2552 2553 return SCTP_DISPOSITION_CONSUME; 2554 2555 nomem: 2556 return SCTP_DISPOSITION_NOMEM; 2557 } 2558 2559 /* 2560 * Process an ABORT. 2561 * 2562 * Section: 9.1 2563 * After checking the Verification Tag, the receiving endpoint shall 2564 * remove the association from its record, and shall report the 2565 * termination to its upper layer. 2566 * 2567 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2568 * B) Rules for packet carrying ABORT: 2569 * 2570 * - The endpoint shall always fill in the Verification Tag field of the 2571 * outbound packet with the destination endpoint's tag value if it 2572 * is known. 2573 * 2574 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2575 * MUST follow the procedure described in Section 8.4. 2576 * 2577 * - The receiver MUST accept the packet if the Verification Tag 2578 * matches either its own tag, OR the tag of its peer. Otherwise, the 2579 * receiver MUST silently discard the packet and take no further 2580 * action. 2581 * 2582 * Inputs 2583 * (endpoint, asoc, chunk) 2584 * 2585 * Outputs 2586 * (asoc, reply_msg, msg_up, timers, counters) 2587 * 2588 * The return value is the disposition of the chunk. 2589 */ 2590 enum sctp_disposition sctp_sf_do_9_1_abort( 2591 struct net *net, 2592 const struct sctp_endpoint *ep, 2593 const struct sctp_association *asoc, 2594 const union sctp_subtype type, 2595 void *arg, 2596 struct sctp_cmd_seq *commands) 2597 { 2598 struct sctp_chunk *chunk = arg; 2599 2600 if (!sctp_vtag_verify_either(chunk, asoc)) 2601 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2602 2603 /* Make sure that the ABORT chunk has a valid length. 2604 * Since this is an ABORT chunk, we have to discard it 2605 * because of the following text: 2606 * RFC 2960, Section 3.3.7 2607 * If an endpoint receives an ABORT with a format error or for an 2608 * association that doesn't exist, it MUST silently discard it. 2609 * Because the length is "invalid", we can't really discard just 2610 * as we do not know its true length. So, to be safe, discard the 2611 * packet. 2612 */ 2613 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2614 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2615 2616 /* ADD-IP: Special case for ABORT chunks 2617 * F4) One special consideration is that ABORT Chunks arriving 2618 * destined to the IP address being deleted MUST be 2619 * ignored (see Section 5.3.1 for further details). 2620 */ 2621 if (SCTP_ADDR_DEL == 2622 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2623 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2624 2625 if (!sctp_err_chunk_valid(chunk)) 2626 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2627 2628 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2629 } 2630 2631 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2632 struct net *net, 2633 const struct sctp_endpoint *ep, 2634 const struct sctp_association *asoc, 2635 const union sctp_subtype type, 2636 void *arg, 2637 struct sctp_cmd_seq *commands) 2638 { 2639 __be16 error = SCTP_ERROR_NO_ERROR; 2640 struct sctp_chunk *chunk = arg; 2641 unsigned int len; 2642 2643 /* See if we have an error cause code in the chunk. */ 2644 len = ntohs(chunk->chunk_hdr->length); 2645 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2646 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2647 2648 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2649 /* ASSOC_FAILED will DELETE_TCB. */ 2650 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2651 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2652 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2653 2654 return SCTP_DISPOSITION_ABORT; 2655 } 2656 2657 /* 2658 * Process an ABORT. (COOKIE-WAIT state) 2659 * 2660 * See sctp_sf_do_9_1_abort() above. 2661 */ 2662 enum sctp_disposition sctp_sf_cookie_wait_abort( 2663 struct net *net, 2664 const struct sctp_endpoint *ep, 2665 const struct sctp_association *asoc, 2666 const union sctp_subtype type, 2667 void *arg, 2668 struct sctp_cmd_seq *commands) 2669 { 2670 __be16 error = SCTP_ERROR_NO_ERROR; 2671 struct sctp_chunk *chunk = arg; 2672 unsigned int len; 2673 2674 if (!sctp_vtag_verify_either(chunk, asoc)) 2675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2676 2677 /* Make sure that the ABORT chunk has a valid length. 2678 * Since this is an ABORT chunk, we have to discard it 2679 * because of the following text: 2680 * RFC 2960, Section 3.3.7 2681 * If an endpoint receives an ABORT with a format error or for an 2682 * association that doesn't exist, it MUST silently discard it. 2683 * Because the length is "invalid", we can't really discard just 2684 * as we do not know its true length. So, to be safe, discard the 2685 * packet. 2686 */ 2687 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2688 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2689 2690 /* See if we have an error cause code in the chunk. */ 2691 len = ntohs(chunk->chunk_hdr->length); 2692 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2693 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2694 2695 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2696 chunk->transport); 2697 } 2698 2699 /* 2700 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2701 */ 2702 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2703 struct net *net, 2704 const struct sctp_endpoint *ep, 2705 const struct sctp_association *asoc, 2706 const union sctp_subtype type, 2707 void *arg, 2708 struct sctp_cmd_seq *commands) 2709 { 2710 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2711 ENOPROTOOPT, asoc, 2712 (struct sctp_transport *)arg); 2713 } 2714 2715 /* 2716 * Process an ABORT. (COOKIE-ECHOED state) 2717 */ 2718 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2719 struct net *net, 2720 const struct sctp_endpoint *ep, 2721 const struct sctp_association *asoc, 2722 const union sctp_subtype type, 2723 void *arg, 2724 struct sctp_cmd_seq *commands) 2725 { 2726 /* There is a single T1 timer, so we should be able to use 2727 * common function with the COOKIE-WAIT state. 2728 */ 2729 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2730 } 2731 2732 /* 2733 * Stop T1 timer and abort association with "INIT failed". 2734 * 2735 * This is common code called by several sctp_sf_*_abort() functions above. 2736 */ 2737 static enum sctp_disposition sctp_stop_t1_and_abort( 2738 struct net *net, 2739 struct sctp_cmd_seq *commands, 2740 __be16 error, int sk_err, 2741 const struct sctp_association *asoc, 2742 struct sctp_transport *transport) 2743 { 2744 pr_debug("%s: ABORT received (INIT)\n", __func__); 2745 2746 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2747 SCTP_STATE(SCTP_STATE_CLOSED)); 2748 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2749 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2750 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2751 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2752 /* CMD_INIT_FAILED will DELETE_TCB. */ 2753 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2754 SCTP_PERR(error)); 2755 2756 return SCTP_DISPOSITION_ABORT; 2757 } 2758 2759 /* 2760 * sctp_sf_do_9_2_shut 2761 * 2762 * Section: 9.2 2763 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2764 * - enter the SHUTDOWN-RECEIVED state, 2765 * 2766 * - stop accepting new data from its SCTP user 2767 * 2768 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2769 * that all its outstanding DATA chunks have been received by the 2770 * SHUTDOWN sender. 2771 * 2772 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2773 * send a SHUTDOWN in response to a ULP request. And should discard 2774 * subsequent SHUTDOWN chunks. 2775 * 2776 * If there are still outstanding DATA chunks left, the SHUTDOWN 2777 * receiver shall continue to follow normal data transmission 2778 * procedures defined in Section 6 until all outstanding DATA chunks 2779 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2780 * new data from its SCTP user. 2781 * 2782 * Verification Tag: 8.5 Verification Tag [Normal verification] 2783 * 2784 * Inputs 2785 * (endpoint, asoc, chunk) 2786 * 2787 * Outputs 2788 * (asoc, reply_msg, msg_up, timers, counters) 2789 * 2790 * The return value is the disposition of the chunk. 2791 */ 2792 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2793 struct net *net, 2794 const struct sctp_endpoint *ep, 2795 const struct sctp_association *asoc, 2796 const union sctp_subtype type, 2797 void *arg, 2798 struct sctp_cmd_seq *commands) 2799 { 2800 enum sctp_disposition disposition; 2801 struct sctp_chunk *chunk = arg; 2802 struct sctp_shutdownhdr *sdh; 2803 struct sctp_ulpevent *ev; 2804 __u32 ctsn; 2805 2806 if (!sctp_vtag_verify(chunk, asoc)) 2807 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2808 2809 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2810 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2811 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2812 commands); 2813 2814 /* Convert the elaborate header. */ 2815 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2816 skb_pull(chunk->skb, sizeof(*sdh)); 2817 chunk->subh.shutdown_hdr = sdh; 2818 ctsn = ntohl(sdh->cum_tsn_ack); 2819 2820 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2821 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2822 asoc->ctsn_ack_point); 2823 2824 return SCTP_DISPOSITION_DISCARD; 2825 } 2826 2827 /* If Cumulative TSN Ack beyond the max tsn currently 2828 * send, terminating the association and respond to the 2829 * sender with an ABORT. 2830 */ 2831 if (!TSN_lt(ctsn, asoc->next_tsn)) 2832 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2833 2834 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2835 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2836 * inform the application that it should cease sending data. 2837 */ 2838 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2839 if (!ev) { 2840 disposition = SCTP_DISPOSITION_NOMEM; 2841 goto out; 2842 } 2843 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2844 2845 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2846 * - enter the SHUTDOWN-RECEIVED state, 2847 * - stop accepting new data from its SCTP user 2848 * 2849 * [This is implicit in the new state.] 2850 */ 2851 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2852 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2853 disposition = SCTP_DISPOSITION_CONSUME; 2854 2855 if (sctp_outq_is_empty(&asoc->outqueue)) { 2856 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2857 arg, commands); 2858 } 2859 2860 if (SCTP_DISPOSITION_NOMEM == disposition) 2861 goto out; 2862 2863 /* - verify, by checking the Cumulative TSN Ack field of the 2864 * chunk, that all its outstanding DATA chunks have been 2865 * received by the SHUTDOWN sender. 2866 */ 2867 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2868 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2869 2870 out: 2871 return disposition; 2872 } 2873 2874 /* 2875 * sctp_sf_do_9_2_shut_ctsn 2876 * 2877 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2878 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2879 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2880 * MUST be processed. 2881 */ 2882 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2883 struct net *net, 2884 const struct sctp_endpoint *ep, 2885 const struct sctp_association *asoc, 2886 const union sctp_subtype type, 2887 void *arg, 2888 struct sctp_cmd_seq *commands) 2889 { 2890 struct sctp_chunk *chunk = arg; 2891 struct sctp_shutdownhdr *sdh; 2892 __u32 ctsn; 2893 2894 if (!sctp_vtag_verify(chunk, asoc)) 2895 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2896 2897 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2898 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2899 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2900 commands); 2901 2902 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2903 ctsn = ntohl(sdh->cum_tsn_ack); 2904 2905 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2906 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2907 asoc->ctsn_ack_point); 2908 2909 return SCTP_DISPOSITION_DISCARD; 2910 } 2911 2912 /* If Cumulative TSN Ack beyond the max tsn currently 2913 * send, terminating the association and respond to the 2914 * sender with an ABORT. 2915 */ 2916 if (!TSN_lt(ctsn, asoc->next_tsn)) 2917 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2918 2919 /* verify, by checking the Cumulative TSN Ack field of the 2920 * chunk, that all its outstanding DATA chunks have been 2921 * received by the SHUTDOWN sender. 2922 */ 2923 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2924 SCTP_BE32(sdh->cum_tsn_ack)); 2925 2926 return SCTP_DISPOSITION_CONSUME; 2927 } 2928 2929 /* RFC 2960 9.2 2930 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2931 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2932 * transport addresses (either in the IP addresses or in the INIT chunk) 2933 * that belong to this association, it should discard the INIT chunk and 2934 * retransmit the SHUTDOWN ACK chunk. 2935 */ 2936 enum sctp_disposition sctp_sf_do_9_2_reshutack( 2937 struct net *net, 2938 const struct sctp_endpoint *ep, 2939 const struct sctp_association *asoc, 2940 const union sctp_subtype type, 2941 void *arg, 2942 struct sctp_cmd_seq *commands) 2943 { 2944 struct sctp_chunk *chunk = arg; 2945 struct sctp_chunk *reply; 2946 2947 /* Make sure that the chunk has a valid length */ 2948 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2949 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2950 commands); 2951 2952 /* Since we are not going to really process this INIT, there 2953 * is no point in verifying chunk boundries. Just generate 2954 * the SHUTDOWN ACK. 2955 */ 2956 reply = sctp_make_shutdown_ack(asoc, chunk); 2957 if (NULL == reply) 2958 goto nomem; 2959 2960 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2961 * the T2-SHUTDOWN timer. 2962 */ 2963 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2964 2965 /* and restart the T2-shutdown timer. */ 2966 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2967 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2968 2969 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2970 2971 return SCTP_DISPOSITION_CONSUME; 2972 nomem: 2973 return SCTP_DISPOSITION_NOMEM; 2974 } 2975 2976 /* 2977 * sctp_sf_do_ecn_cwr 2978 * 2979 * Section: Appendix A: Explicit Congestion Notification 2980 * 2981 * CWR: 2982 * 2983 * RFC 2481 details a specific bit for a sender to send in the header of 2984 * its next outbound TCP segment to indicate to its peer that it has 2985 * reduced its congestion window. This is termed the CWR bit. For 2986 * SCTP the same indication is made by including the CWR chunk. 2987 * This chunk contains one data element, i.e. the TSN number that 2988 * was sent in the ECNE chunk. This element represents the lowest 2989 * TSN number in the datagram that was originally marked with the 2990 * CE bit. 2991 * 2992 * Verification Tag: 8.5 Verification Tag [Normal verification] 2993 * Inputs 2994 * (endpoint, asoc, chunk) 2995 * 2996 * Outputs 2997 * (asoc, reply_msg, msg_up, timers, counters) 2998 * 2999 * The return value is the disposition of the chunk. 3000 */ 3001 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3002 const struct sctp_endpoint *ep, 3003 const struct sctp_association *asoc, 3004 const union sctp_subtype type, 3005 void *arg, 3006 struct sctp_cmd_seq *commands) 3007 { 3008 struct sctp_chunk *chunk = arg; 3009 struct sctp_cwrhdr *cwr; 3010 u32 lowest_tsn; 3011 3012 if (!sctp_vtag_verify(chunk, asoc)) 3013 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3014 3015 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3016 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3017 commands); 3018 3019 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3020 skb_pull(chunk->skb, sizeof(*cwr)); 3021 3022 lowest_tsn = ntohl(cwr->lowest_tsn); 3023 3024 /* Does this CWR ack the last sent congestion notification? */ 3025 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3026 /* Stop sending ECNE. */ 3027 sctp_add_cmd_sf(commands, 3028 SCTP_CMD_ECN_CWR, 3029 SCTP_U32(lowest_tsn)); 3030 } 3031 return SCTP_DISPOSITION_CONSUME; 3032 } 3033 3034 /* 3035 * sctp_sf_do_ecne 3036 * 3037 * Section: Appendix A: Explicit Congestion Notification 3038 * 3039 * ECN-Echo 3040 * 3041 * RFC 2481 details a specific bit for a receiver to send back in its 3042 * TCP acknowledgements to notify the sender of the Congestion 3043 * Experienced (CE) bit having arrived from the network. For SCTP this 3044 * same indication is made by including the ECNE chunk. This chunk 3045 * contains one data element, i.e. the lowest TSN associated with the IP 3046 * datagram marked with the CE bit..... 3047 * 3048 * Verification Tag: 8.5 Verification Tag [Normal verification] 3049 * Inputs 3050 * (endpoint, asoc, chunk) 3051 * 3052 * Outputs 3053 * (asoc, reply_msg, msg_up, timers, counters) 3054 * 3055 * The return value is the disposition of the chunk. 3056 */ 3057 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3058 const struct sctp_endpoint *ep, 3059 const struct sctp_association *asoc, 3060 const union sctp_subtype type, 3061 void *arg, struct sctp_cmd_seq *commands) 3062 { 3063 struct sctp_chunk *chunk = arg; 3064 struct sctp_ecnehdr *ecne; 3065 3066 if (!sctp_vtag_verify(chunk, asoc)) 3067 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3068 3069 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3070 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3071 commands); 3072 3073 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3074 skb_pull(chunk->skb, sizeof(*ecne)); 3075 3076 /* If this is a newer ECNE than the last CWR packet we sent out */ 3077 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3078 SCTP_U32(ntohl(ecne->lowest_tsn))); 3079 3080 return SCTP_DISPOSITION_CONSUME; 3081 } 3082 3083 /* 3084 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3085 * 3086 * The SCTP endpoint MUST always acknowledge the reception of each valid 3087 * DATA chunk. 3088 * 3089 * The guidelines on delayed acknowledgement algorithm specified in 3090 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3091 * acknowledgement SHOULD be generated for at least every second packet 3092 * (not every second DATA chunk) received, and SHOULD be generated within 3093 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3094 * situations it may be beneficial for an SCTP transmitter to be more 3095 * conservative than the algorithms detailed in this document allow. 3096 * However, an SCTP transmitter MUST NOT be more aggressive than the 3097 * following algorithms allow. 3098 * 3099 * A SCTP receiver MUST NOT generate more than one SACK for every 3100 * incoming packet, other than to update the offered window as the 3101 * receiving application consumes new data. 3102 * 3103 * Verification Tag: 8.5 Verification Tag [Normal verification] 3104 * 3105 * Inputs 3106 * (endpoint, asoc, chunk) 3107 * 3108 * Outputs 3109 * (asoc, reply_msg, msg_up, timers, counters) 3110 * 3111 * The return value is the disposition of the chunk. 3112 */ 3113 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3114 const struct sctp_endpoint *ep, 3115 const struct sctp_association *asoc, 3116 const union sctp_subtype type, 3117 void *arg, 3118 struct sctp_cmd_seq *commands) 3119 { 3120 union sctp_arg force = SCTP_NOFORCE(); 3121 struct sctp_chunk *chunk = arg; 3122 int error; 3123 3124 if (!sctp_vtag_verify(chunk, asoc)) { 3125 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3126 SCTP_NULL()); 3127 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3128 } 3129 3130 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3131 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3132 commands); 3133 3134 error = sctp_eat_data(asoc, chunk, commands); 3135 switch (error) { 3136 case SCTP_IERROR_NO_ERROR: 3137 break; 3138 case SCTP_IERROR_HIGH_TSN: 3139 case SCTP_IERROR_BAD_STREAM: 3140 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3141 goto discard_noforce; 3142 case SCTP_IERROR_DUP_TSN: 3143 case SCTP_IERROR_IGNORE_TSN: 3144 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3145 goto discard_force; 3146 case SCTP_IERROR_NO_DATA: 3147 return SCTP_DISPOSITION_ABORT; 3148 case SCTP_IERROR_PROTO_VIOLATION: 3149 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3150 (u8 *)chunk->subh.data_hdr, 3151 sctp_datahdr_len(&asoc->stream)); 3152 default: 3153 BUG(); 3154 } 3155 3156 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3157 force = SCTP_FORCE(); 3158 3159 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3160 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3161 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3162 } 3163 3164 /* If this is the last chunk in a packet, we need to count it 3165 * toward sack generation. Note that we need to SACK every 3166 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3167 * THEM. We elect to NOT generate SACK's if the chunk fails 3168 * the verification tag test. 3169 * 3170 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3171 * 3172 * The SCTP endpoint MUST always acknowledge the reception of 3173 * each valid DATA chunk. 3174 * 3175 * The guidelines on delayed acknowledgement algorithm 3176 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3177 * Specifically, an acknowledgement SHOULD be generated for at 3178 * least every second packet (not every second DATA chunk) 3179 * received, and SHOULD be generated within 200 ms of the 3180 * arrival of any unacknowledged DATA chunk. In some 3181 * situations it may be beneficial for an SCTP transmitter to 3182 * be more conservative than the algorithms detailed in this 3183 * document allow. However, an SCTP transmitter MUST NOT be 3184 * more aggressive than the following algorithms allow. 3185 */ 3186 if (chunk->end_of_packet) 3187 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3188 3189 return SCTP_DISPOSITION_CONSUME; 3190 3191 discard_force: 3192 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3193 * 3194 * When a packet arrives with duplicate DATA chunk(s) and with 3195 * no new DATA chunk(s), the endpoint MUST immediately send a 3196 * SACK with no delay. If a packet arrives with duplicate 3197 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3198 * MAY immediately send a SACK. Normally receipt of duplicate 3199 * DATA chunks will occur when the original SACK chunk was lost 3200 * and the peer's RTO has expired. The duplicate TSN number(s) 3201 * SHOULD be reported in the SACK as duplicate. 3202 */ 3203 /* In our case, we split the MAY SACK advice up whether or not 3204 * the last chunk is a duplicate.' 3205 */ 3206 if (chunk->end_of_packet) 3207 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3208 return SCTP_DISPOSITION_DISCARD; 3209 3210 discard_noforce: 3211 if (chunk->end_of_packet) 3212 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3213 3214 return SCTP_DISPOSITION_DISCARD; 3215 } 3216 3217 /* 3218 * sctp_sf_eat_data_fast_4_4 3219 * 3220 * Section: 4 (4) 3221 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3222 * DATA chunks without delay. 3223 * 3224 * Verification Tag: 8.5 Verification Tag [Normal verification] 3225 * Inputs 3226 * (endpoint, asoc, chunk) 3227 * 3228 * Outputs 3229 * (asoc, reply_msg, msg_up, timers, counters) 3230 * 3231 * The return value is the disposition of the chunk. 3232 */ 3233 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3234 struct net *net, 3235 const struct sctp_endpoint *ep, 3236 const struct sctp_association *asoc, 3237 const union sctp_subtype type, 3238 void *arg, 3239 struct sctp_cmd_seq *commands) 3240 { 3241 struct sctp_chunk *chunk = arg; 3242 int error; 3243 3244 if (!sctp_vtag_verify(chunk, asoc)) { 3245 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3246 SCTP_NULL()); 3247 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3248 } 3249 3250 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3251 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3252 commands); 3253 3254 error = sctp_eat_data(asoc, chunk, commands); 3255 switch (error) { 3256 case SCTP_IERROR_NO_ERROR: 3257 case SCTP_IERROR_HIGH_TSN: 3258 case SCTP_IERROR_DUP_TSN: 3259 case SCTP_IERROR_IGNORE_TSN: 3260 case SCTP_IERROR_BAD_STREAM: 3261 break; 3262 case SCTP_IERROR_NO_DATA: 3263 return SCTP_DISPOSITION_ABORT; 3264 case SCTP_IERROR_PROTO_VIOLATION: 3265 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3266 (u8 *)chunk->subh.data_hdr, 3267 sctp_datahdr_len(&asoc->stream)); 3268 default: 3269 BUG(); 3270 } 3271 3272 /* Go a head and force a SACK, since we are shutting down. */ 3273 3274 /* Implementor's Guide. 3275 * 3276 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3277 * respond to each received packet containing one or more DATA chunk(s) 3278 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3279 */ 3280 if (chunk->end_of_packet) { 3281 /* We must delay the chunk creation since the cumulative 3282 * TSN has not been updated yet. 3283 */ 3284 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3285 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3286 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3287 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3288 } 3289 3290 return SCTP_DISPOSITION_CONSUME; 3291 } 3292 3293 /* 3294 * Section: 6.2 Processing a Received SACK 3295 * D) Any time a SACK arrives, the endpoint performs the following: 3296 * 3297 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3298 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3299 * increasing, a SACK whose Cumulative TSN Ack is less than the 3300 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3301 * 3302 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3303 * of bytes still outstanding after processing the Cumulative TSN Ack 3304 * and the Gap Ack Blocks. 3305 * 3306 * iii) If the SACK is missing a TSN that was previously 3307 * acknowledged via a Gap Ack Block (e.g., the data receiver 3308 * reneged on the data), then mark the corresponding DATA chunk 3309 * as available for retransmit: Mark it as missing for fast 3310 * retransmit as described in Section 7.2.4 and if no retransmit 3311 * timer is running for the destination address to which the DATA 3312 * chunk was originally transmitted, then T3-rtx is started for 3313 * that destination address. 3314 * 3315 * Verification Tag: 8.5 Verification Tag [Normal verification] 3316 * 3317 * Inputs 3318 * (endpoint, asoc, chunk) 3319 * 3320 * Outputs 3321 * (asoc, reply_msg, msg_up, timers, counters) 3322 * 3323 * The return value is the disposition of the chunk. 3324 */ 3325 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3326 const struct sctp_endpoint *ep, 3327 const struct sctp_association *asoc, 3328 const union sctp_subtype type, 3329 void *arg, 3330 struct sctp_cmd_seq *commands) 3331 { 3332 struct sctp_chunk *chunk = arg; 3333 struct sctp_sackhdr *sackh; 3334 __u32 ctsn; 3335 3336 if (!sctp_vtag_verify(chunk, asoc)) 3337 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3338 3339 /* Make sure that the SACK chunk has a valid length. */ 3340 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3341 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3342 commands); 3343 3344 /* Pull the SACK chunk from the data buffer */ 3345 sackh = sctp_sm_pull_sack(chunk); 3346 /* Was this a bogus SACK? */ 3347 if (!sackh) 3348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3349 chunk->subh.sack_hdr = sackh; 3350 ctsn = ntohl(sackh->cum_tsn_ack); 3351 3352 /* If Cumulative TSN Ack beyond the max tsn currently 3353 * send, terminating the association and respond to the 3354 * sender with an ABORT. 3355 */ 3356 if (TSN_lte(asoc->next_tsn, ctsn)) 3357 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3358 3359 trace_sctp_probe(ep, asoc, chunk); 3360 3361 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3362 * Ack Point, then drop the SACK. Since Cumulative TSN 3363 * Ack is monotonically increasing, a SACK whose 3364 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3365 * Point indicates an out-of-order SACK. 3366 */ 3367 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3368 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3369 asoc->ctsn_ack_point); 3370 3371 return SCTP_DISPOSITION_DISCARD; 3372 } 3373 3374 /* Return this SACK for further processing. */ 3375 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3376 3377 /* Note: We do the rest of the work on the PROCESS_SACK 3378 * sideeffect. 3379 */ 3380 return SCTP_DISPOSITION_CONSUME; 3381 } 3382 3383 /* 3384 * Generate an ABORT in response to a packet. 3385 * 3386 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3387 * 3388 * 8) The receiver should respond to the sender of the OOTB packet with 3389 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3390 * MUST fill in the Verification Tag field of the outbound packet 3391 * with the value found in the Verification Tag field of the OOTB 3392 * packet and set the T-bit in the Chunk Flags to indicate that the 3393 * Verification Tag is reflected. After sending this ABORT, the 3394 * receiver of the OOTB packet shall discard the OOTB packet and take 3395 * no further action. 3396 * 3397 * Verification Tag: 3398 * 3399 * The return value is the disposition of the chunk. 3400 */ 3401 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3402 struct net *net, 3403 const struct sctp_endpoint *ep, 3404 const struct sctp_association *asoc, 3405 const union sctp_subtype type, 3406 void *arg, 3407 struct sctp_cmd_seq *commands) 3408 { 3409 struct sctp_packet *packet = NULL; 3410 struct sctp_chunk *chunk = arg; 3411 struct sctp_chunk *abort; 3412 3413 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3414 if (!packet) 3415 return SCTP_DISPOSITION_NOMEM; 3416 3417 /* Make an ABORT. The T bit will be set if the asoc 3418 * is NULL. 3419 */ 3420 abort = sctp_make_abort(asoc, chunk, 0); 3421 if (!abort) { 3422 sctp_ootb_pkt_free(packet); 3423 return SCTP_DISPOSITION_NOMEM; 3424 } 3425 3426 /* Reflect vtag if T-Bit is set */ 3427 if (sctp_test_T_bit(abort)) 3428 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3429 3430 /* Set the skb to the belonging sock for accounting. */ 3431 abort->skb->sk = ep->base.sk; 3432 3433 sctp_packet_append_chunk(packet, abort); 3434 3435 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3436 3437 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3438 3439 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3440 return SCTP_DISPOSITION_CONSUME; 3441 } 3442 3443 /* Handling of SCTP Packets Containing an INIT Chunk Matching an 3444 * Existing Associations when the UDP encap port is incorrect. 3445 * 3446 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3447 */ 3448 static enum sctp_disposition sctp_sf_new_encap_port( 3449 struct net *net, 3450 const struct sctp_endpoint *ep, 3451 const struct sctp_association *asoc, 3452 const union sctp_subtype type, 3453 void *arg, 3454 struct sctp_cmd_seq *commands) 3455 { 3456 struct sctp_packet *packet = NULL; 3457 struct sctp_chunk *chunk = arg; 3458 struct sctp_chunk *abort; 3459 3460 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3461 if (!packet) 3462 return SCTP_DISPOSITION_NOMEM; 3463 3464 abort = sctp_make_new_encap_port(asoc, chunk); 3465 if (!abort) { 3466 sctp_ootb_pkt_free(packet); 3467 return SCTP_DISPOSITION_NOMEM; 3468 } 3469 3470 abort->skb->sk = ep->base.sk; 3471 3472 sctp_packet_append_chunk(packet, abort); 3473 3474 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3475 SCTP_PACKET(packet)); 3476 3477 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3478 3479 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3480 return SCTP_DISPOSITION_CONSUME; 3481 } 3482 3483 /* 3484 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3485 * event as ULP notification for each cause included in the chunk. 3486 * 3487 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3488 * 3489 * The return value is the disposition of the chunk. 3490 */ 3491 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3492 const struct sctp_endpoint *ep, 3493 const struct sctp_association *asoc, 3494 const union sctp_subtype type, 3495 void *arg, 3496 struct sctp_cmd_seq *commands) 3497 { 3498 struct sctp_chunk *chunk = arg; 3499 struct sctp_errhdr *err; 3500 3501 if (!sctp_vtag_verify(chunk, asoc)) 3502 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3503 3504 /* Make sure that the ERROR chunk has a valid length. */ 3505 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3506 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3507 commands); 3508 sctp_walk_errors(err, chunk->chunk_hdr); 3509 if ((void *)err != (void *)chunk->chunk_end) 3510 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3511 (void *)err, commands); 3512 3513 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3514 SCTP_CHUNK(chunk)); 3515 3516 return SCTP_DISPOSITION_CONSUME; 3517 } 3518 3519 /* 3520 * Process an inbound SHUTDOWN ACK. 3521 * 3522 * From Section 9.2: 3523 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3524 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3525 * peer, and remove all record of the association. 3526 * 3527 * The return value is the disposition. 3528 */ 3529 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3530 const struct sctp_endpoint *ep, 3531 const struct sctp_association *asoc, 3532 const union sctp_subtype type, 3533 void *arg, 3534 struct sctp_cmd_seq *commands) 3535 { 3536 struct sctp_chunk *chunk = arg; 3537 struct sctp_chunk *reply; 3538 struct sctp_ulpevent *ev; 3539 3540 if (!sctp_vtag_verify(chunk, asoc)) 3541 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3542 3543 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3544 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3545 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3546 commands); 3547 /* 10.2 H) SHUTDOWN COMPLETE notification 3548 * 3549 * When SCTP completes the shutdown procedures (section 9.2) this 3550 * notification is passed to the upper layer. 3551 */ 3552 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3553 0, 0, 0, NULL, GFP_ATOMIC); 3554 if (!ev) 3555 goto nomem; 3556 3557 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3558 reply = sctp_make_shutdown_complete(asoc, chunk); 3559 if (!reply) 3560 goto nomem_chunk; 3561 3562 /* Do all the commands now (after allocation), so that we 3563 * have consistent state if memory allocation failes 3564 */ 3565 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3566 3567 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3568 * stop the T2-shutdown timer, 3569 */ 3570 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3571 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3572 3573 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3574 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3575 3576 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3577 SCTP_STATE(SCTP_STATE_CLOSED)); 3578 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3579 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3580 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3581 3582 /* ...and remove all record of the association. */ 3583 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3584 return SCTP_DISPOSITION_DELETE_TCB; 3585 3586 nomem_chunk: 3587 sctp_ulpevent_free(ev); 3588 nomem: 3589 return SCTP_DISPOSITION_NOMEM; 3590 } 3591 3592 /* 3593 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3594 * 3595 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3596 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3597 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3598 * packet must fill in the Verification Tag field of the outbound 3599 * packet with the Verification Tag received in the SHUTDOWN ACK and 3600 * set the T-bit in the Chunk Flags to indicate that the Verification 3601 * Tag is reflected. 3602 * 3603 * 8) The receiver should respond to the sender of the OOTB packet with 3604 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3605 * MUST fill in the Verification Tag field of the outbound packet 3606 * with the value found in the Verification Tag field of the OOTB 3607 * packet and set the T-bit in the Chunk Flags to indicate that the 3608 * Verification Tag is reflected. After sending this ABORT, the 3609 * receiver of the OOTB packet shall discard the OOTB packet and take 3610 * no further action. 3611 */ 3612 enum sctp_disposition sctp_sf_ootb(struct net *net, 3613 const struct sctp_endpoint *ep, 3614 const struct sctp_association *asoc, 3615 const union sctp_subtype type, 3616 void *arg, struct sctp_cmd_seq *commands) 3617 { 3618 struct sctp_chunk *chunk = arg; 3619 struct sk_buff *skb = chunk->skb; 3620 struct sctp_chunkhdr *ch; 3621 struct sctp_errhdr *err; 3622 int ootb_cookie_ack = 0; 3623 int ootb_shut_ack = 0; 3624 __u8 *ch_end; 3625 3626 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3627 3628 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3629 do { 3630 /* Report violation if the chunk is less then minimal */ 3631 if (ntohs(ch->length) < sizeof(*ch)) 3632 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3633 commands); 3634 3635 /* Report violation if chunk len overflows */ 3636 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3637 if (ch_end > skb_tail_pointer(skb)) 3638 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3639 commands); 3640 3641 /* Now that we know we at least have a chunk header, 3642 * do things that are type appropriate. 3643 */ 3644 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3645 ootb_shut_ack = 1; 3646 3647 /* RFC 2960, Section 3.3.7 3648 * Moreover, under any circumstances, an endpoint that 3649 * receives an ABORT MUST NOT respond to that ABORT by 3650 * sending an ABORT of its own. 3651 */ 3652 if (SCTP_CID_ABORT == ch->type) 3653 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3654 3655 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3656 * or a COOKIE ACK the SCTP Packet should be silently 3657 * discarded. 3658 */ 3659 3660 if (SCTP_CID_COOKIE_ACK == ch->type) 3661 ootb_cookie_ack = 1; 3662 3663 if (SCTP_CID_ERROR == ch->type) { 3664 sctp_walk_errors(err, ch) { 3665 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3666 ootb_cookie_ack = 1; 3667 break; 3668 } 3669 } 3670 } 3671 3672 ch = (struct sctp_chunkhdr *)ch_end; 3673 } while (ch_end < skb_tail_pointer(skb)); 3674 3675 if (ootb_shut_ack) 3676 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3677 else if (ootb_cookie_ack) 3678 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3679 else 3680 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3681 } 3682 3683 /* 3684 * Handle an "Out of the blue" SHUTDOWN ACK. 3685 * 3686 * Section: 8.4 5, sctpimpguide 2.41. 3687 * 3688 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3689 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3690 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3691 * packet must fill in the Verification Tag field of the outbound 3692 * packet with the Verification Tag received in the SHUTDOWN ACK and 3693 * set the T-bit in the Chunk Flags to indicate that the Verification 3694 * Tag is reflected. 3695 * 3696 * Inputs 3697 * (endpoint, asoc, type, arg, commands) 3698 * 3699 * Outputs 3700 * (enum sctp_disposition) 3701 * 3702 * The return value is the disposition of the chunk. 3703 */ 3704 static enum sctp_disposition sctp_sf_shut_8_4_5( 3705 struct net *net, 3706 const struct sctp_endpoint *ep, 3707 const struct sctp_association *asoc, 3708 const union sctp_subtype type, 3709 void *arg, 3710 struct sctp_cmd_seq *commands) 3711 { 3712 struct sctp_packet *packet = NULL; 3713 struct sctp_chunk *chunk = arg; 3714 struct sctp_chunk *shut; 3715 3716 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3717 if (!packet) 3718 return SCTP_DISPOSITION_NOMEM; 3719 3720 /* Make an SHUTDOWN_COMPLETE. 3721 * The T bit will be set if the asoc is NULL. 3722 */ 3723 shut = sctp_make_shutdown_complete(asoc, chunk); 3724 if (!shut) { 3725 sctp_ootb_pkt_free(packet); 3726 return SCTP_DISPOSITION_NOMEM; 3727 } 3728 3729 /* Reflect vtag if T-Bit is set */ 3730 if (sctp_test_T_bit(shut)) 3731 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3732 3733 /* Set the skb to the belonging sock for accounting. */ 3734 shut->skb->sk = ep->base.sk; 3735 3736 sctp_packet_append_chunk(packet, shut); 3737 3738 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3739 SCTP_PACKET(packet)); 3740 3741 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3742 3743 /* If the chunk length is invalid, we don't want to process 3744 * the reset of the packet. 3745 */ 3746 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3747 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3748 3749 /* We need to discard the rest of the packet to prevent 3750 * potential bomming attacks from additional bundled chunks. 3751 * This is documented in SCTP Threats ID. 3752 */ 3753 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3754 } 3755 3756 /* 3757 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3758 * 3759 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3760 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3761 * procedures in section 8.4 SHOULD be followed, in other words it 3762 * should be treated as an Out Of The Blue packet. 3763 * [This means that we do NOT check the Verification Tag on these 3764 * chunks. --piggy ] 3765 * 3766 */ 3767 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3768 const struct sctp_endpoint *ep, 3769 const struct sctp_association *asoc, 3770 const union sctp_subtype type, 3771 void *arg, 3772 struct sctp_cmd_seq *commands) 3773 { 3774 struct sctp_chunk *chunk = arg; 3775 3776 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3777 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3778 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3779 commands); 3780 3781 /* Although we do have an association in this case, it corresponds 3782 * to a restarted association. So the packet is treated as an OOTB 3783 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3784 * called with a NULL association. 3785 */ 3786 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3787 3788 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3789 } 3790 3791 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3792 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3793 const struct sctp_endpoint *ep, 3794 const struct sctp_association *asoc, 3795 const union sctp_subtype type, 3796 void *arg, 3797 struct sctp_cmd_seq *commands) 3798 { 3799 struct sctp_paramhdr *err_param = NULL; 3800 struct sctp_chunk *asconf_ack = NULL; 3801 struct sctp_chunk *chunk = arg; 3802 struct sctp_addiphdr *hdr; 3803 __u32 serial; 3804 3805 if (!sctp_vtag_verify(chunk, asoc)) { 3806 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3807 SCTP_NULL()); 3808 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3809 } 3810 3811 /* ADD-IP: Section 4.1.1 3812 * This chunk MUST be sent in an authenticated way by using 3813 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3814 * is received unauthenticated it MUST be silently discarded as 3815 * described in [I-D.ietf-tsvwg-sctp-auth]. 3816 */ 3817 if (!asoc->peer.asconf_capable || 3818 (!net->sctp.addip_noauth && !chunk->auth)) 3819 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3820 commands); 3821 3822 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3823 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3824 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3825 commands); 3826 3827 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3828 serial = ntohl(hdr->serial); 3829 3830 /* Verify the ASCONF chunk before processing it. */ 3831 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3832 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3833 (void *)err_param, commands); 3834 3835 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3836 * the endpoint stored in a new association variable 3837 * 'Peer-Serial-Number'. 3838 */ 3839 if (serial == asoc->peer.addip_serial + 1) { 3840 /* If this is the first instance of ASCONF in the packet, 3841 * we can clean our old ASCONF-ACKs. 3842 */ 3843 if (!chunk->has_asconf) 3844 sctp_assoc_clean_asconf_ack_cache(asoc); 3845 3846 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3847 * expected, process the ASCONF as described below and after 3848 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3849 * the response packet and cache a copy of it (in the event it 3850 * later needs to be retransmitted). 3851 * 3852 * Essentially, do V1-V5. 3853 */ 3854 asconf_ack = sctp_process_asconf((struct sctp_association *) 3855 asoc, chunk); 3856 if (!asconf_ack) 3857 return SCTP_DISPOSITION_NOMEM; 3858 } else if (serial < asoc->peer.addip_serial + 1) { 3859 /* ADDIP 5.2 E2) 3860 * If the value found in the Sequence Number is less than the 3861 * ('Peer- Sequence-Number' + 1), simply skip to the next 3862 * ASCONF, and include in the outbound response packet 3863 * any previously cached ASCONF-ACK response that was 3864 * sent and saved that matches the Sequence Number of the 3865 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3866 * Chunk exists. This will occur when an older ASCONF 3867 * arrives out of order. In such a case, the receiver 3868 * should skip the ASCONF Chunk and not include ASCONF-ACK 3869 * Chunk for that chunk. 3870 */ 3871 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3872 if (!asconf_ack) 3873 return SCTP_DISPOSITION_DISCARD; 3874 3875 /* Reset the transport so that we select the correct one 3876 * this time around. This is to make sure that we don't 3877 * accidentally use a stale transport that's been removed. 3878 */ 3879 asconf_ack->transport = NULL; 3880 } else { 3881 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3882 * it must be either a stale packet or from an attacker. 3883 */ 3884 return SCTP_DISPOSITION_DISCARD; 3885 } 3886 3887 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3888 * containing the ASCONF-ACK Chunks MUST be the source address of 3889 * the SCTP packet that held the ASCONF Chunks. 3890 * 3891 * To do this properly, we'll set the destination address of the chunk 3892 * and at the transmit time, will try look up the transport to use. 3893 * Since ASCONFs may be bundled, the correct transport may not be 3894 * created until we process the entire packet, thus this workaround. 3895 */ 3896 asconf_ack->dest = chunk->source; 3897 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3898 if (asoc->new_transport) { 3899 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3900 ((struct sctp_association *)asoc)->new_transport = NULL; 3901 } 3902 3903 return SCTP_DISPOSITION_CONSUME; 3904 } 3905 3906 static enum sctp_disposition sctp_send_next_asconf( 3907 struct net *net, 3908 const struct sctp_endpoint *ep, 3909 struct sctp_association *asoc, 3910 const union sctp_subtype type, 3911 struct sctp_cmd_seq *commands) 3912 { 3913 struct sctp_chunk *asconf; 3914 struct list_head *entry; 3915 3916 if (list_empty(&asoc->addip_chunk_list)) 3917 return SCTP_DISPOSITION_CONSUME; 3918 3919 entry = asoc->addip_chunk_list.next; 3920 asconf = list_entry(entry, struct sctp_chunk, list); 3921 3922 list_del_init(entry); 3923 sctp_chunk_hold(asconf); 3924 asoc->addip_last_asconf = asconf; 3925 3926 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 3927 } 3928 3929 /* 3930 * ADDIP Section 4.3 General rules for address manipulation 3931 * When building TLV parameters for the ASCONF Chunk that will add or 3932 * delete IP addresses the D0 to D13 rules should be applied: 3933 */ 3934 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 3935 const struct sctp_endpoint *ep, 3936 const struct sctp_association *asoc, 3937 const union sctp_subtype type, 3938 void *arg, 3939 struct sctp_cmd_seq *commands) 3940 { 3941 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3942 struct sctp_paramhdr *err_param = NULL; 3943 struct sctp_chunk *asconf_ack = arg; 3944 struct sctp_addiphdr *addip_hdr; 3945 __u32 sent_serial, rcvd_serial; 3946 struct sctp_chunk *abort; 3947 3948 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3949 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3950 SCTP_NULL()); 3951 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3952 } 3953 3954 /* ADD-IP, Section 4.1.2: 3955 * This chunk MUST be sent in an authenticated way by using 3956 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3957 * is received unauthenticated it MUST be silently discarded as 3958 * described in [I-D.ietf-tsvwg-sctp-auth]. 3959 */ 3960 if (!asoc->peer.asconf_capable || 3961 (!net->sctp.addip_noauth && !asconf_ack->auth)) 3962 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3963 commands); 3964 3965 /* Make sure that the ADDIP chunk has a valid length. */ 3966 if (!sctp_chunk_length_valid(asconf_ack, 3967 sizeof(struct sctp_addip_chunk))) 3968 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3969 commands); 3970 3971 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 3972 rcvd_serial = ntohl(addip_hdr->serial); 3973 3974 /* Verify the ASCONF-ACK chunk before processing it. */ 3975 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3976 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3977 (void *)err_param, commands); 3978 3979 if (last_asconf) { 3980 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr; 3981 sent_serial = ntohl(addip_hdr->serial); 3982 } else { 3983 sent_serial = asoc->addip_serial - 1; 3984 } 3985 3986 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3987 * equal to the next serial number to be used but no ASCONF chunk is 3988 * outstanding the endpoint MUST ABORT the association. Note that a 3989 * sequence number is greater than if it is no more than 2^^31-1 3990 * larger than the current sequence number (using serial arithmetic). 3991 */ 3992 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3993 !(asoc->addip_last_asconf)) { 3994 abort = sctp_make_abort(asoc, asconf_ack, 3995 sizeof(struct sctp_errhdr)); 3996 if (abort) { 3997 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3998 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3999 SCTP_CHUNK(abort)); 4000 } 4001 /* We are going to ABORT, so we might as well stop 4002 * processing the rest of the chunks in the packet. 4003 */ 4004 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4005 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4006 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4007 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4008 SCTP_ERROR(ECONNABORTED)); 4009 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4010 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4011 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4012 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4013 return SCTP_DISPOSITION_ABORT; 4014 } 4015 4016 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4017 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4018 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4019 4020 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4021 asconf_ack)) 4022 return sctp_send_next_asconf(net, ep, 4023 (struct sctp_association *)asoc, 4024 type, commands); 4025 4026 abort = sctp_make_abort(asoc, asconf_ack, 4027 sizeof(struct sctp_errhdr)); 4028 if (abort) { 4029 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4030 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4031 SCTP_CHUNK(abort)); 4032 } 4033 /* We are going to ABORT, so we might as well stop 4034 * processing the rest of the chunks in the packet. 4035 */ 4036 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4037 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4038 SCTP_ERROR(ECONNABORTED)); 4039 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4040 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4041 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4042 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4043 return SCTP_DISPOSITION_ABORT; 4044 } 4045 4046 return SCTP_DISPOSITION_DISCARD; 4047 } 4048 4049 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4050 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4051 const struct sctp_endpoint *ep, 4052 const struct sctp_association *asoc, 4053 const union sctp_subtype type, 4054 void *arg, 4055 struct sctp_cmd_seq *commands) 4056 { 4057 struct sctp_paramhdr *err_param = NULL; 4058 struct sctp_chunk *chunk = arg; 4059 struct sctp_reconf_chunk *hdr; 4060 union sctp_params param; 4061 4062 if (!sctp_vtag_verify(chunk, asoc)) { 4063 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4064 SCTP_NULL()); 4065 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4066 } 4067 4068 /* Make sure that the RECONF chunk has a valid length. */ 4069 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4070 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4071 commands); 4072 4073 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4074 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4075 (void *)err_param, commands); 4076 4077 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4078 sctp_walk_params(param, hdr, params) { 4079 struct sctp_chunk *reply = NULL; 4080 struct sctp_ulpevent *ev = NULL; 4081 4082 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4083 reply = sctp_process_strreset_outreq( 4084 (struct sctp_association *)asoc, param, &ev); 4085 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4086 reply = sctp_process_strreset_inreq( 4087 (struct sctp_association *)asoc, param, &ev); 4088 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4089 reply = sctp_process_strreset_tsnreq( 4090 (struct sctp_association *)asoc, param, &ev); 4091 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4092 reply = sctp_process_strreset_addstrm_out( 4093 (struct sctp_association *)asoc, param, &ev); 4094 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4095 reply = sctp_process_strreset_addstrm_in( 4096 (struct sctp_association *)asoc, param, &ev); 4097 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4098 reply = sctp_process_strreset_resp( 4099 (struct sctp_association *)asoc, param, &ev); 4100 4101 if (ev) 4102 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4103 SCTP_ULPEVENT(ev)); 4104 4105 if (reply) 4106 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4107 SCTP_CHUNK(reply)); 4108 } 4109 4110 return SCTP_DISPOSITION_CONSUME; 4111 } 4112 4113 /* 4114 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4115 * 4116 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4117 * its cumulative TSN point to the value carried in the FORWARD TSN 4118 * chunk, and then MUST further advance its cumulative TSN point locally 4119 * if possible. 4120 * After the above processing, the data receiver MUST stop reporting any 4121 * missing TSNs earlier than or equal to the new cumulative TSN point. 4122 * 4123 * Verification Tag: 8.5 Verification Tag [Normal verification] 4124 * 4125 * The return value is the disposition of the chunk. 4126 */ 4127 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4128 const struct sctp_endpoint *ep, 4129 const struct sctp_association *asoc, 4130 const union sctp_subtype type, 4131 void *arg, 4132 struct sctp_cmd_seq *commands) 4133 { 4134 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4135 struct sctp_chunk *chunk = arg; 4136 __u16 len; 4137 __u32 tsn; 4138 4139 if (!sctp_vtag_verify(chunk, asoc)) { 4140 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4141 SCTP_NULL()); 4142 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4143 } 4144 4145 if (!asoc->peer.prsctp_capable) 4146 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4147 4148 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4149 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4150 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4151 commands); 4152 4153 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4154 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4155 len = ntohs(chunk->chunk_hdr->length); 4156 len -= sizeof(struct sctp_chunkhdr); 4157 skb_pull(chunk->skb, len); 4158 4159 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4160 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4161 4162 /* The TSN is too high--silently discard the chunk and count on it 4163 * getting retransmitted later. 4164 */ 4165 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4166 goto discard_noforce; 4167 4168 if (!asoc->stream.si->validate_ftsn(chunk)) 4169 goto discard_noforce; 4170 4171 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4172 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4173 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4174 SCTP_CHUNK(chunk)); 4175 4176 /* Count this as receiving DATA. */ 4177 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4178 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4179 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4180 } 4181 4182 /* FIXME: For now send a SACK, but DATA processing may 4183 * send another. 4184 */ 4185 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4186 4187 return SCTP_DISPOSITION_CONSUME; 4188 4189 discard_noforce: 4190 return SCTP_DISPOSITION_DISCARD; 4191 } 4192 4193 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4194 struct net *net, 4195 const struct sctp_endpoint *ep, 4196 const struct sctp_association *asoc, 4197 const union sctp_subtype type, 4198 void *arg, 4199 struct sctp_cmd_seq *commands) 4200 { 4201 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4202 struct sctp_chunk *chunk = arg; 4203 __u16 len; 4204 __u32 tsn; 4205 4206 if (!sctp_vtag_verify(chunk, asoc)) { 4207 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4208 SCTP_NULL()); 4209 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4210 } 4211 4212 if (!asoc->peer.prsctp_capable) 4213 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4214 4215 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4216 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4217 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4218 commands); 4219 4220 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4221 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4222 len = ntohs(chunk->chunk_hdr->length); 4223 len -= sizeof(struct sctp_chunkhdr); 4224 skb_pull(chunk->skb, len); 4225 4226 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4227 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4228 4229 /* The TSN is too high--silently discard the chunk and count on it 4230 * getting retransmitted later. 4231 */ 4232 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4233 goto gen_shutdown; 4234 4235 if (!asoc->stream.si->validate_ftsn(chunk)) 4236 goto gen_shutdown; 4237 4238 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4239 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4240 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4241 SCTP_CHUNK(chunk)); 4242 4243 /* Go a head and force a SACK, since we are shutting down. */ 4244 gen_shutdown: 4245 /* Implementor's Guide. 4246 * 4247 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4248 * respond to each received packet containing one or more DATA chunk(s) 4249 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4250 */ 4251 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4252 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4254 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4255 4256 return SCTP_DISPOSITION_CONSUME; 4257 } 4258 4259 /* 4260 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4261 * 4262 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4263 * Identifier field. If this algorithm was not specified by the 4264 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4265 * during association setup, the AUTH chunk and all chunks after it MUST 4266 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4267 * defined in Section 4.1. 4268 * 4269 * If an endpoint with no shared key receives a Shared Key Identifier 4270 * other than 0, it MUST silently discard all authenticated chunks. If 4271 * the endpoint has at least one endpoint pair shared key for the peer, 4272 * it MUST use the key specified by the Shared Key Identifier if a 4273 * key has been configured for that Shared Key Identifier. If no 4274 * endpoint pair shared key has been configured for that Shared Key 4275 * Identifier, all authenticated chunks MUST be silently discarded. 4276 * 4277 * Verification Tag: 8.5 Verification Tag [Normal verification] 4278 * 4279 * The return value is the disposition of the chunk. 4280 */ 4281 static enum sctp_ierror sctp_sf_authenticate( 4282 const struct sctp_association *asoc, 4283 struct sctp_chunk *chunk) 4284 { 4285 struct sctp_shared_key *sh_key = NULL; 4286 struct sctp_authhdr *auth_hdr; 4287 __u8 *save_digest, *digest; 4288 struct sctp_hmac *hmac; 4289 unsigned int sig_len; 4290 __u16 key_id; 4291 4292 /* Pull in the auth header, so we can do some more verification */ 4293 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4294 chunk->subh.auth_hdr = auth_hdr; 4295 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4296 4297 /* Make sure that we support the HMAC algorithm from the auth 4298 * chunk. 4299 */ 4300 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4301 return SCTP_IERROR_AUTH_BAD_HMAC; 4302 4303 /* Make sure that the provided shared key identifier has been 4304 * configured 4305 */ 4306 key_id = ntohs(auth_hdr->shkey_id); 4307 if (key_id != asoc->active_key_id) { 4308 sh_key = sctp_auth_get_shkey(asoc, key_id); 4309 if (!sh_key) 4310 return SCTP_IERROR_AUTH_BAD_KEYID; 4311 } 4312 4313 /* Make sure that the length of the signature matches what 4314 * we expect. 4315 */ 4316 sig_len = ntohs(chunk->chunk_hdr->length) - 4317 sizeof(struct sctp_auth_chunk); 4318 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4319 if (sig_len != hmac->hmac_len) 4320 return SCTP_IERROR_PROTO_VIOLATION; 4321 4322 /* Now that we've done validation checks, we can compute and 4323 * verify the hmac. The steps involved are: 4324 * 1. Save the digest from the chunk. 4325 * 2. Zero out the digest in the chunk. 4326 * 3. Compute the new digest 4327 * 4. Compare saved and new digests. 4328 */ 4329 digest = auth_hdr->hmac; 4330 skb_pull(chunk->skb, sig_len); 4331 4332 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4333 if (!save_digest) 4334 goto nomem; 4335 4336 memset(digest, 0, sig_len); 4337 4338 sctp_auth_calculate_hmac(asoc, chunk->skb, 4339 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4340 sh_key, GFP_ATOMIC); 4341 4342 /* Discard the packet if the digests do not match */ 4343 if (memcmp(save_digest, digest, sig_len)) { 4344 kfree(save_digest); 4345 return SCTP_IERROR_BAD_SIG; 4346 } 4347 4348 kfree(save_digest); 4349 chunk->auth = 1; 4350 4351 return SCTP_IERROR_NO_ERROR; 4352 nomem: 4353 return SCTP_IERROR_NOMEM; 4354 } 4355 4356 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4357 const struct sctp_endpoint *ep, 4358 const struct sctp_association *asoc, 4359 const union sctp_subtype type, 4360 void *arg, struct sctp_cmd_seq *commands) 4361 { 4362 struct sctp_chunk *chunk = arg; 4363 struct sctp_authhdr *auth_hdr; 4364 struct sctp_chunk *err_chunk; 4365 enum sctp_ierror error; 4366 4367 /* Make sure that the peer has AUTH capable */ 4368 if (!asoc->peer.auth_capable) 4369 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4370 4371 if (!sctp_vtag_verify(chunk, asoc)) { 4372 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4373 SCTP_NULL()); 4374 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4375 } 4376 4377 /* Make sure that the AUTH chunk has valid length. */ 4378 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4379 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4380 commands); 4381 4382 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4383 error = sctp_sf_authenticate(asoc, chunk); 4384 switch (error) { 4385 case SCTP_IERROR_AUTH_BAD_HMAC: 4386 /* Generate the ERROR chunk and discard the rest 4387 * of the packet 4388 */ 4389 err_chunk = sctp_make_op_error(asoc, chunk, 4390 SCTP_ERROR_UNSUP_HMAC, 4391 &auth_hdr->hmac_id, 4392 sizeof(__u16), 0); 4393 if (err_chunk) { 4394 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4395 SCTP_CHUNK(err_chunk)); 4396 } 4397 fallthrough; 4398 case SCTP_IERROR_AUTH_BAD_KEYID: 4399 case SCTP_IERROR_BAD_SIG: 4400 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4401 4402 case SCTP_IERROR_PROTO_VIOLATION: 4403 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4404 commands); 4405 4406 case SCTP_IERROR_NOMEM: 4407 return SCTP_DISPOSITION_NOMEM; 4408 4409 default: /* Prevent gcc warnings */ 4410 break; 4411 } 4412 4413 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4414 struct sctp_ulpevent *ev; 4415 4416 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4417 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4418 4419 if (!ev) 4420 return -ENOMEM; 4421 4422 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4423 SCTP_ULPEVENT(ev)); 4424 } 4425 4426 return SCTP_DISPOSITION_CONSUME; 4427 } 4428 4429 /* 4430 * Process an unknown chunk. 4431 * 4432 * Section: 3.2. Also, 2.1 in the implementor's guide. 4433 * 4434 * Chunk Types are encoded such that the highest-order two bits specify 4435 * the action that must be taken if the processing endpoint does not 4436 * recognize the Chunk Type. 4437 * 4438 * 00 - Stop processing this SCTP packet and discard it, do not process 4439 * any further chunks within it. 4440 * 4441 * 01 - Stop processing this SCTP packet and discard it, do not process 4442 * any further chunks within it, and report the unrecognized 4443 * chunk in an 'Unrecognized Chunk Type'. 4444 * 4445 * 10 - Skip this chunk and continue processing. 4446 * 4447 * 11 - Skip this chunk and continue processing, but report in an ERROR 4448 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4449 * 4450 * The return value is the disposition of the chunk. 4451 */ 4452 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4453 const struct sctp_endpoint *ep, 4454 const struct sctp_association *asoc, 4455 const union sctp_subtype type, 4456 void *arg, 4457 struct sctp_cmd_seq *commands) 4458 { 4459 struct sctp_chunk *unk_chunk = arg; 4460 struct sctp_chunk *err_chunk; 4461 struct sctp_chunkhdr *hdr; 4462 4463 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4464 4465 if (!sctp_vtag_verify(unk_chunk, asoc)) 4466 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4467 4468 /* Make sure that the chunk has a valid length. 4469 * Since we don't know the chunk type, we use a general 4470 * chunkhdr structure to make a comparison. 4471 */ 4472 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4473 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4474 commands); 4475 4476 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4477 case SCTP_CID_ACTION_DISCARD: 4478 /* Discard the packet. */ 4479 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4480 case SCTP_CID_ACTION_DISCARD_ERR: 4481 /* Generate an ERROR chunk as response. */ 4482 hdr = unk_chunk->chunk_hdr; 4483 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4484 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4485 SCTP_PAD4(ntohs(hdr->length)), 4486 0); 4487 if (err_chunk) { 4488 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4489 SCTP_CHUNK(err_chunk)); 4490 } 4491 4492 /* Discard the packet. */ 4493 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4494 return SCTP_DISPOSITION_CONSUME; 4495 case SCTP_CID_ACTION_SKIP: 4496 /* Skip the chunk. */ 4497 return SCTP_DISPOSITION_DISCARD; 4498 case SCTP_CID_ACTION_SKIP_ERR: 4499 /* Generate an ERROR chunk as response. */ 4500 hdr = unk_chunk->chunk_hdr; 4501 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4502 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4503 SCTP_PAD4(ntohs(hdr->length)), 4504 0); 4505 if (err_chunk) { 4506 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4507 SCTP_CHUNK(err_chunk)); 4508 } 4509 /* Skip the chunk. */ 4510 return SCTP_DISPOSITION_CONSUME; 4511 default: 4512 break; 4513 } 4514 4515 return SCTP_DISPOSITION_DISCARD; 4516 } 4517 4518 /* 4519 * Discard the chunk. 4520 * 4521 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4522 * [Too numerous to mention...] 4523 * Verification Tag: No verification needed. 4524 * Inputs 4525 * (endpoint, asoc, chunk) 4526 * 4527 * Outputs 4528 * (asoc, reply_msg, msg_up, timers, counters) 4529 * 4530 * The return value is the disposition of the chunk. 4531 */ 4532 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4533 const struct sctp_endpoint *ep, 4534 const struct sctp_association *asoc, 4535 const union sctp_subtype type, 4536 void *arg, 4537 struct sctp_cmd_seq *commands) 4538 { 4539 struct sctp_chunk *chunk = arg; 4540 4541 /* Make sure that the chunk has a valid length. 4542 * Since we don't know the chunk type, we use a general 4543 * chunkhdr structure to make a comparison. 4544 */ 4545 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4546 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4547 commands); 4548 4549 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4550 4551 return SCTP_DISPOSITION_DISCARD; 4552 } 4553 4554 /* 4555 * Discard the whole packet. 4556 * 4557 * Section: 8.4 2) 4558 * 4559 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4560 * silently discard the OOTB packet and take no further action. 4561 * 4562 * Verification Tag: No verification necessary 4563 * 4564 * Inputs 4565 * (endpoint, asoc, chunk) 4566 * 4567 * Outputs 4568 * (asoc, reply_msg, msg_up, timers, counters) 4569 * 4570 * The return value is the disposition of the chunk. 4571 */ 4572 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4573 const struct sctp_endpoint *ep, 4574 const struct sctp_association *asoc, 4575 const union sctp_subtype type, 4576 void *arg, struct sctp_cmd_seq *commands) 4577 { 4578 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4579 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4580 4581 return SCTP_DISPOSITION_CONSUME; 4582 } 4583 4584 4585 /* 4586 * The other end is violating protocol. 4587 * 4588 * Section: Not specified 4589 * Verification Tag: Not specified 4590 * Inputs 4591 * (endpoint, asoc, chunk) 4592 * 4593 * Outputs 4594 * (asoc, reply_msg, msg_up, timers, counters) 4595 * 4596 * We simply tag the chunk as a violation. The state machine will log 4597 * the violation and continue. 4598 */ 4599 enum sctp_disposition sctp_sf_violation(struct net *net, 4600 const struct sctp_endpoint *ep, 4601 const struct sctp_association *asoc, 4602 const union sctp_subtype type, 4603 void *arg, 4604 struct sctp_cmd_seq *commands) 4605 { 4606 struct sctp_chunk *chunk = arg; 4607 4608 /* Make sure that the chunk has a valid length. */ 4609 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4610 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4611 commands); 4612 4613 return SCTP_DISPOSITION_VIOLATION; 4614 } 4615 4616 /* 4617 * Common function to handle a protocol violation. 4618 */ 4619 static enum sctp_disposition sctp_sf_abort_violation( 4620 struct net *net, 4621 const struct sctp_endpoint *ep, 4622 const struct sctp_association *asoc, 4623 void *arg, 4624 struct sctp_cmd_seq *commands, 4625 const __u8 *payload, 4626 const size_t paylen) 4627 { 4628 struct sctp_packet *packet = NULL; 4629 struct sctp_chunk *chunk = arg; 4630 struct sctp_chunk *abort = NULL; 4631 4632 /* SCTP-AUTH, Section 6.3: 4633 * It should be noted that if the receiver wants to tear 4634 * down an association in an authenticated way only, the 4635 * handling of malformed packets should not result in 4636 * tearing down the association. 4637 * 4638 * This means that if we only want to abort associations 4639 * in an authenticated way (i.e AUTH+ABORT), then we 4640 * can't destroy this association just because the packet 4641 * was malformed. 4642 */ 4643 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4644 goto discard; 4645 4646 /* Make the abort chunk. */ 4647 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4648 if (!abort) 4649 goto nomem; 4650 4651 if (asoc) { 4652 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4653 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4654 !asoc->peer.i.init_tag) { 4655 struct sctp_initack_chunk *initack; 4656 4657 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4658 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4659 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4660 else { 4661 unsigned int inittag; 4662 4663 inittag = ntohl(initack->init_hdr.init_tag); 4664 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4665 SCTP_U32(inittag)); 4666 } 4667 } 4668 4669 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4670 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4671 4672 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4673 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4674 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4675 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4676 SCTP_ERROR(ECONNREFUSED)); 4677 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4678 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4679 } else { 4680 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4681 SCTP_ERROR(ECONNABORTED)); 4682 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4683 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4684 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4685 } 4686 } else { 4687 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4688 4689 if (!packet) 4690 goto nomem_pkt; 4691 4692 if (sctp_test_T_bit(abort)) 4693 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4694 4695 abort->skb->sk = ep->base.sk; 4696 4697 sctp_packet_append_chunk(packet, abort); 4698 4699 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4700 SCTP_PACKET(packet)); 4701 4702 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4703 } 4704 4705 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4706 4707 discard: 4708 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4709 return SCTP_DISPOSITION_ABORT; 4710 4711 nomem_pkt: 4712 sctp_chunk_free(abort); 4713 nomem: 4714 return SCTP_DISPOSITION_NOMEM; 4715 } 4716 4717 /* 4718 * Handle a protocol violation when the chunk length is invalid. 4719 * "Invalid" length is identified as smaller than the minimal length a 4720 * given chunk can be. For example, a SACK chunk has invalid length 4721 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4722 * 4723 * We inform the other end by sending an ABORT with a Protocol Violation 4724 * error code. 4725 * 4726 * Section: Not specified 4727 * Verification Tag: Nothing to do 4728 * Inputs 4729 * (endpoint, asoc, chunk) 4730 * 4731 * Outputs 4732 * (reply_msg, msg_up, counters) 4733 * 4734 * Generate an ABORT chunk and terminate the association. 4735 */ 4736 static enum sctp_disposition sctp_sf_violation_chunklen( 4737 struct net *net, 4738 const struct sctp_endpoint *ep, 4739 const struct sctp_association *asoc, 4740 const union sctp_subtype type, 4741 void *arg, 4742 struct sctp_cmd_seq *commands) 4743 { 4744 static const char err_str[] = "The following chunk had invalid length:"; 4745 4746 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4747 sizeof(err_str)); 4748 } 4749 4750 /* 4751 * Handle a protocol violation when the parameter length is invalid. 4752 * If the length is smaller than the minimum length of a given parameter, 4753 * or accumulated length in multi parameters exceeds the end of the chunk, 4754 * the length is considered as invalid. 4755 */ 4756 static enum sctp_disposition sctp_sf_violation_paramlen( 4757 struct net *net, 4758 const struct sctp_endpoint *ep, 4759 const struct sctp_association *asoc, 4760 const union sctp_subtype type, 4761 void *arg, void *ext, 4762 struct sctp_cmd_seq *commands) 4763 { 4764 struct sctp_paramhdr *param = ext; 4765 struct sctp_chunk *abort = NULL; 4766 struct sctp_chunk *chunk = arg; 4767 4768 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4769 goto discard; 4770 4771 /* Make the abort chunk. */ 4772 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4773 if (!abort) 4774 goto nomem; 4775 4776 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4777 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4778 4779 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4780 SCTP_ERROR(ECONNABORTED)); 4781 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4782 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4783 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4784 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4785 4786 discard: 4787 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4788 return SCTP_DISPOSITION_ABORT; 4789 nomem: 4790 return SCTP_DISPOSITION_NOMEM; 4791 } 4792 4793 /* Handle a protocol violation when the peer trying to advance the 4794 * cumulative tsn ack to a point beyond the max tsn currently sent. 4795 * 4796 * We inform the other end by sending an ABORT with a Protocol Violation 4797 * error code. 4798 */ 4799 static enum sctp_disposition sctp_sf_violation_ctsn( 4800 struct net *net, 4801 const struct sctp_endpoint *ep, 4802 const struct sctp_association *asoc, 4803 const union sctp_subtype type, 4804 void *arg, 4805 struct sctp_cmd_seq *commands) 4806 { 4807 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4808 4809 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4810 sizeof(err_str)); 4811 } 4812 4813 /* Handle protocol violation of an invalid chunk bundling. For example, 4814 * when we have an association and we receive bundled INIT-ACK, or 4815 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4816 * statement from the specs. Additionally, there might be an attacker 4817 * on the path and we may not want to continue this communication. 4818 */ 4819 static enum sctp_disposition sctp_sf_violation_chunk( 4820 struct net *net, 4821 const struct sctp_endpoint *ep, 4822 const struct sctp_association *asoc, 4823 const union sctp_subtype type, 4824 void *arg, 4825 struct sctp_cmd_seq *commands) 4826 { 4827 static const char err_str[] = "The following chunk violates protocol:"; 4828 4829 if (!asoc) 4830 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4831 4832 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4833 sizeof(err_str)); 4834 } 4835 /*************************************************************************** 4836 * These are the state functions for handling primitive (Section 10) events. 4837 ***************************************************************************/ 4838 /* 4839 * sctp_sf_do_prm_asoc 4840 * 4841 * Section: 10.1 ULP-to-SCTP 4842 * B) Associate 4843 * 4844 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4845 * outbound stream count) 4846 * -> association id [,destination transport addr list] [,outbound stream 4847 * count] 4848 * 4849 * This primitive allows the upper layer to initiate an association to a 4850 * specific peer endpoint. 4851 * 4852 * The peer endpoint shall be specified by one of the transport addresses 4853 * which defines the endpoint (see Section 1.4). If the local SCTP 4854 * instance has not been initialized, the ASSOCIATE is considered an 4855 * error. 4856 * [This is not relevant for the kernel implementation since we do all 4857 * initialization at boot time. It we hadn't initialized we wouldn't 4858 * get anywhere near this code.] 4859 * 4860 * An association id, which is a local handle to the SCTP association, 4861 * will be returned on successful establishment of the association. If 4862 * SCTP is not able to open an SCTP association with the peer endpoint, 4863 * an error is returned. 4864 * [In the kernel implementation, the struct sctp_association needs to 4865 * be created BEFORE causing this primitive to run.] 4866 * 4867 * Other association parameters may be returned, including the 4868 * complete destination transport addresses of the peer as well as the 4869 * outbound stream count of the local endpoint. One of the transport 4870 * address from the returned destination addresses will be selected by 4871 * the local endpoint as default primary path for sending SCTP packets 4872 * to this peer. The returned "destination transport addr list" can 4873 * be used by the ULP to change the default primary path or to force 4874 * sending a packet to a specific transport address. [All of this 4875 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4876 * function.] 4877 * 4878 * Mandatory attributes: 4879 * 4880 * o local SCTP instance name - obtained from the INITIALIZE operation. 4881 * [This is the argument asoc.] 4882 * o destination transport addr - specified as one of the transport 4883 * addresses of the peer endpoint with which the association is to be 4884 * established. 4885 * [This is asoc->peer.active_path.] 4886 * o outbound stream count - the number of outbound streams the ULP 4887 * would like to open towards this peer endpoint. 4888 * [BUG: This is not currently implemented.] 4889 * Optional attributes: 4890 * 4891 * None. 4892 * 4893 * The return value is a disposition. 4894 */ 4895 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4896 const struct sctp_endpoint *ep, 4897 const struct sctp_association *asoc, 4898 const union sctp_subtype type, 4899 void *arg, 4900 struct sctp_cmd_seq *commands) 4901 { 4902 struct sctp_association *my_asoc; 4903 struct sctp_chunk *repl; 4904 4905 /* The comment below says that we enter COOKIE-WAIT AFTER 4906 * sending the INIT, but that doesn't actually work in our 4907 * implementation... 4908 */ 4909 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4910 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4911 4912 /* RFC 2960 5.1 Normal Establishment of an Association 4913 * 4914 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4915 * must provide its Verification Tag (Tag_A) in the Initiate 4916 * Tag field. Tag_A SHOULD be a random number in the range of 4917 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4918 */ 4919 4920 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4921 if (!repl) 4922 goto nomem; 4923 4924 /* Choose transport for INIT. */ 4925 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4926 SCTP_CHUNK(repl)); 4927 4928 /* Cast away the const modifier, as we want to just 4929 * rerun it through as a sideffect. 4930 */ 4931 my_asoc = (struct sctp_association *)asoc; 4932 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4933 4934 /* After sending the INIT, "A" starts the T1-init timer and 4935 * enters the COOKIE-WAIT state. 4936 */ 4937 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4938 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4939 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4940 return SCTP_DISPOSITION_CONSUME; 4941 4942 nomem: 4943 return SCTP_DISPOSITION_NOMEM; 4944 } 4945 4946 /* 4947 * Process the SEND primitive. 4948 * 4949 * Section: 10.1 ULP-to-SCTP 4950 * E) Send 4951 * 4952 * Format: SEND(association id, buffer address, byte count [,context] 4953 * [,stream id] [,life time] [,destination transport address] 4954 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4955 * -> result 4956 * 4957 * This is the main method to send user data via SCTP. 4958 * 4959 * Mandatory attributes: 4960 * 4961 * o association id - local handle to the SCTP association 4962 * 4963 * o buffer address - the location where the user message to be 4964 * transmitted is stored; 4965 * 4966 * o byte count - The size of the user data in number of bytes; 4967 * 4968 * Optional attributes: 4969 * 4970 * o context - an optional 32 bit integer that will be carried in the 4971 * sending failure notification to the ULP if the transportation of 4972 * this User Message fails. 4973 * 4974 * o stream id - to indicate which stream to send the data on. If not 4975 * specified, stream 0 will be used. 4976 * 4977 * o life time - specifies the life time of the user data. The user data 4978 * will not be sent by SCTP after the life time expires. This 4979 * parameter can be used to avoid efforts to transmit stale 4980 * user messages. SCTP notifies the ULP if the data cannot be 4981 * initiated to transport (i.e. sent to the destination via SCTP's 4982 * send primitive) within the life time variable. However, the 4983 * user data will be transmitted if SCTP has attempted to transmit a 4984 * chunk before the life time expired. 4985 * 4986 * o destination transport address - specified as one of the destination 4987 * transport addresses of the peer endpoint to which this packet 4988 * should be sent. Whenever possible, SCTP should use this destination 4989 * transport address for sending the packets, instead of the current 4990 * primary path. 4991 * 4992 * o unorder flag - this flag, if present, indicates that the user 4993 * would like the data delivered in an unordered fashion to the peer 4994 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4995 * message). 4996 * 4997 * o no-bundle flag - instructs SCTP not to bundle this user data with 4998 * other outbound DATA chunks. SCTP MAY still bundle even when 4999 * this flag is present, when faced with network congestion. 5000 * 5001 * o payload protocol-id - A 32 bit unsigned integer that is to be 5002 * passed to the peer indicating the type of payload protocol data 5003 * being transmitted. This value is passed as opaque data by SCTP. 5004 * 5005 * The return value is the disposition. 5006 */ 5007 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5008 const struct sctp_endpoint *ep, 5009 const struct sctp_association *asoc, 5010 const union sctp_subtype type, 5011 void *arg, 5012 struct sctp_cmd_seq *commands) 5013 { 5014 struct sctp_datamsg *msg = arg; 5015 5016 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5017 return SCTP_DISPOSITION_CONSUME; 5018 } 5019 5020 /* 5021 * Process the SHUTDOWN primitive. 5022 * 5023 * Section: 10.1: 5024 * C) Shutdown 5025 * 5026 * Format: SHUTDOWN(association id) 5027 * -> result 5028 * 5029 * Gracefully closes an association. Any locally queued user data 5030 * will be delivered to the peer. The association will be terminated only 5031 * after the peer acknowledges all the SCTP packets sent. A success code 5032 * will be returned on successful termination of the association. If 5033 * attempting to terminate the association results in a failure, an error 5034 * code shall be returned. 5035 * 5036 * Mandatory attributes: 5037 * 5038 * o association id - local handle to the SCTP association 5039 * 5040 * Optional attributes: 5041 * 5042 * None. 5043 * 5044 * The return value is the disposition. 5045 */ 5046 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5047 struct net *net, 5048 const struct sctp_endpoint *ep, 5049 const struct sctp_association *asoc, 5050 const union sctp_subtype type, 5051 void *arg, 5052 struct sctp_cmd_seq *commands) 5053 { 5054 enum sctp_disposition disposition; 5055 5056 /* From 9.2 Shutdown of an Association 5057 * Upon receipt of the SHUTDOWN primitive from its upper 5058 * layer, the endpoint enters SHUTDOWN-PENDING state and 5059 * remains there until all outstanding data has been 5060 * acknowledged by its peer. The endpoint accepts no new data 5061 * from its upper layer, but retransmits data to the far end 5062 * if necessary to fill gaps. 5063 */ 5064 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5065 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5066 5067 disposition = SCTP_DISPOSITION_CONSUME; 5068 if (sctp_outq_is_empty(&asoc->outqueue)) { 5069 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5070 arg, commands); 5071 } 5072 5073 return disposition; 5074 } 5075 5076 /* 5077 * Process the ABORT primitive. 5078 * 5079 * Section: 10.1: 5080 * C) Abort 5081 * 5082 * Format: Abort(association id [, cause code]) 5083 * -> result 5084 * 5085 * Ungracefully closes an association. Any locally queued user data 5086 * will be discarded and an ABORT chunk is sent to the peer. A success code 5087 * will be returned on successful abortion of the association. If 5088 * attempting to abort the association results in a failure, an error 5089 * code shall be returned. 5090 * 5091 * Mandatory attributes: 5092 * 5093 * o association id - local handle to the SCTP association 5094 * 5095 * Optional attributes: 5096 * 5097 * o cause code - reason of the abort to be passed to the peer 5098 * 5099 * None. 5100 * 5101 * The return value is the disposition. 5102 */ 5103 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5104 struct net *net, 5105 const struct sctp_endpoint *ep, 5106 const struct sctp_association *asoc, 5107 const union sctp_subtype type, 5108 void *arg, 5109 struct sctp_cmd_seq *commands) 5110 { 5111 /* From 9.1 Abort of an Association 5112 * Upon receipt of the ABORT primitive from its upper 5113 * layer, the endpoint enters CLOSED state and 5114 * discard all outstanding data has been 5115 * acknowledged by its peer. The endpoint accepts no new data 5116 * from its upper layer, but retransmits data to the far end 5117 * if necessary to fill gaps. 5118 */ 5119 struct sctp_chunk *abort = arg; 5120 5121 if (abort) 5122 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5123 5124 /* Even if we can't send the ABORT due to low memory delete the 5125 * TCB. This is a departure from our typical NOMEM handling. 5126 */ 5127 5128 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5129 SCTP_ERROR(ECONNABORTED)); 5130 /* Delete the established association. */ 5131 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5132 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5133 5134 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5135 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5136 5137 return SCTP_DISPOSITION_ABORT; 5138 } 5139 5140 /* We tried an illegal operation on an association which is closed. */ 5141 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5142 const struct sctp_endpoint *ep, 5143 const struct sctp_association *asoc, 5144 const union sctp_subtype type, 5145 void *arg, 5146 struct sctp_cmd_seq *commands) 5147 { 5148 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5149 return SCTP_DISPOSITION_CONSUME; 5150 } 5151 5152 /* We tried an illegal operation on an association which is shutting 5153 * down. 5154 */ 5155 enum sctp_disposition sctp_sf_error_shutdown( 5156 struct net *net, 5157 const struct sctp_endpoint *ep, 5158 const struct sctp_association *asoc, 5159 const union sctp_subtype type, 5160 void *arg, 5161 struct sctp_cmd_seq *commands) 5162 { 5163 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5164 SCTP_ERROR(-ESHUTDOWN)); 5165 return SCTP_DISPOSITION_CONSUME; 5166 } 5167 5168 /* 5169 * sctp_cookie_wait_prm_shutdown 5170 * 5171 * Section: 4 Note: 2 5172 * Verification Tag: 5173 * Inputs 5174 * (endpoint, asoc) 5175 * 5176 * The RFC does not explicitly address this issue, but is the route through the 5177 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5178 * 5179 * Outputs 5180 * (timers) 5181 */ 5182 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5183 struct net *net, 5184 const struct sctp_endpoint *ep, 5185 const struct sctp_association *asoc, 5186 const union sctp_subtype type, 5187 void *arg, 5188 struct sctp_cmd_seq *commands) 5189 { 5190 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5191 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5192 5193 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5194 SCTP_STATE(SCTP_STATE_CLOSED)); 5195 5196 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5197 5198 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5199 5200 return SCTP_DISPOSITION_DELETE_TCB; 5201 } 5202 5203 /* 5204 * sctp_cookie_echoed_prm_shutdown 5205 * 5206 * Section: 4 Note: 2 5207 * Verification Tag: 5208 * Inputs 5209 * (endpoint, asoc) 5210 * 5211 * The RFC does not explcitly address this issue, but is the route through the 5212 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5213 * 5214 * Outputs 5215 * (timers) 5216 */ 5217 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5218 struct net *net, 5219 const struct sctp_endpoint *ep, 5220 const struct sctp_association *asoc, 5221 const union sctp_subtype type, 5222 void *arg, 5223 struct sctp_cmd_seq *commands) 5224 { 5225 /* There is a single T1 timer, so we should be able to use 5226 * common function with the COOKIE-WAIT state. 5227 */ 5228 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5229 } 5230 5231 /* 5232 * sctp_sf_cookie_wait_prm_abort 5233 * 5234 * Section: 4 Note: 2 5235 * Verification Tag: 5236 * Inputs 5237 * (endpoint, asoc) 5238 * 5239 * The RFC does not explicitly address this issue, but is the route through the 5240 * state table when someone issues an abort while in COOKIE_WAIT state. 5241 * 5242 * Outputs 5243 * (timers) 5244 */ 5245 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5246 struct net *net, 5247 const struct sctp_endpoint *ep, 5248 const struct sctp_association *asoc, 5249 const union sctp_subtype type, 5250 void *arg, 5251 struct sctp_cmd_seq *commands) 5252 { 5253 struct sctp_chunk *abort = arg; 5254 5255 /* Stop T1-init timer */ 5256 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5257 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5258 5259 if (abort) 5260 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5261 5262 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5263 SCTP_STATE(SCTP_STATE_CLOSED)); 5264 5265 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5266 5267 /* Even if we can't send the ABORT due to low memory delete the 5268 * TCB. This is a departure from our typical NOMEM handling. 5269 */ 5270 5271 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5272 SCTP_ERROR(ECONNREFUSED)); 5273 /* Delete the established association. */ 5274 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5275 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5276 5277 return SCTP_DISPOSITION_ABORT; 5278 } 5279 5280 /* 5281 * sctp_sf_cookie_echoed_prm_abort 5282 * 5283 * Section: 4 Note: 3 5284 * Verification Tag: 5285 * Inputs 5286 * (endpoint, asoc) 5287 * 5288 * The RFC does not explcitly address this issue, but is the route through the 5289 * state table when someone issues an abort while in COOKIE_ECHOED state. 5290 * 5291 * Outputs 5292 * (timers) 5293 */ 5294 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5295 struct net *net, 5296 const struct sctp_endpoint *ep, 5297 const struct sctp_association *asoc, 5298 const union sctp_subtype type, 5299 void *arg, 5300 struct sctp_cmd_seq *commands) 5301 { 5302 /* There is a single T1 timer, so we should be able to use 5303 * common function with the COOKIE-WAIT state. 5304 */ 5305 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5306 } 5307 5308 /* 5309 * sctp_sf_shutdown_pending_prm_abort 5310 * 5311 * Inputs 5312 * (endpoint, asoc) 5313 * 5314 * The RFC does not explicitly address this issue, but is the route through the 5315 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5316 * 5317 * Outputs 5318 * (timers) 5319 */ 5320 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5321 struct net *net, 5322 const struct sctp_endpoint *ep, 5323 const struct sctp_association *asoc, 5324 const union sctp_subtype type, 5325 void *arg, 5326 struct sctp_cmd_seq *commands) 5327 { 5328 /* Stop the T5-shutdown guard timer. */ 5329 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5330 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5331 5332 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5333 } 5334 5335 /* 5336 * sctp_sf_shutdown_sent_prm_abort 5337 * 5338 * Inputs 5339 * (endpoint, asoc) 5340 * 5341 * The RFC does not explicitly address this issue, but is the route through the 5342 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5343 * 5344 * Outputs 5345 * (timers) 5346 */ 5347 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5348 struct net *net, 5349 const struct sctp_endpoint *ep, 5350 const struct sctp_association *asoc, 5351 const union sctp_subtype type, 5352 void *arg, 5353 struct sctp_cmd_seq *commands) 5354 { 5355 /* Stop the T2-shutdown timer. */ 5356 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5357 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5358 5359 /* Stop the T5-shutdown guard timer. */ 5360 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5361 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5362 5363 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5364 } 5365 5366 /* 5367 * sctp_sf_cookie_echoed_prm_abort 5368 * 5369 * Inputs 5370 * (endpoint, asoc) 5371 * 5372 * The RFC does not explcitly address this issue, but is the route through the 5373 * state table when someone issues an abort while in COOKIE_ECHOED state. 5374 * 5375 * Outputs 5376 * (timers) 5377 */ 5378 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5379 struct net *net, 5380 const struct sctp_endpoint *ep, 5381 const struct sctp_association *asoc, 5382 const union sctp_subtype type, 5383 void *arg, 5384 struct sctp_cmd_seq *commands) 5385 { 5386 /* The same T2 timer, so we should be able to use 5387 * common function with the SHUTDOWN-SENT state. 5388 */ 5389 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5390 } 5391 5392 /* 5393 * Process the REQUESTHEARTBEAT primitive 5394 * 5395 * 10.1 ULP-to-SCTP 5396 * J) Request Heartbeat 5397 * 5398 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5399 * 5400 * -> result 5401 * 5402 * Instructs the local endpoint to perform a HeartBeat on the specified 5403 * destination transport address of the given association. The returned 5404 * result should indicate whether the transmission of the HEARTBEAT 5405 * chunk to the destination address is successful. 5406 * 5407 * Mandatory attributes: 5408 * 5409 * o association id - local handle to the SCTP association 5410 * 5411 * o destination transport address - the transport address of the 5412 * association on which a heartbeat should be issued. 5413 */ 5414 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5415 struct net *net, 5416 const struct sctp_endpoint *ep, 5417 const struct sctp_association *asoc, 5418 const union sctp_subtype type, 5419 void *arg, 5420 struct sctp_cmd_seq *commands) 5421 { 5422 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5423 (struct sctp_transport *)arg, commands)) 5424 return SCTP_DISPOSITION_NOMEM; 5425 5426 /* 5427 * RFC 2960 (bis), section 8.3 5428 * 5429 * D) Request an on-demand HEARTBEAT on a specific destination 5430 * transport address of a given association. 5431 * 5432 * The endpoint should increment the respective error counter of 5433 * the destination transport address each time a HEARTBEAT is sent 5434 * to that address and not acknowledged within one RTO. 5435 * 5436 */ 5437 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5438 SCTP_TRANSPORT(arg)); 5439 return SCTP_DISPOSITION_CONSUME; 5440 } 5441 5442 /* 5443 * ADDIP Section 4.1 ASCONF Chunk Procedures 5444 * When an endpoint has an ASCONF signaled change to be sent to the 5445 * remote endpoint it should do A1 to A9 5446 */ 5447 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5448 const struct sctp_endpoint *ep, 5449 const struct sctp_association *asoc, 5450 const union sctp_subtype type, 5451 void *arg, 5452 struct sctp_cmd_seq *commands) 5453 { 5454 struct sctp_chunk *chunk = arg; 5455 5456 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5457 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5458 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5459 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5460 return SCTP_DISPOSITION_CONSUME; 5461 } 5462 5463 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5464 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5465 const struct sctp_endpoint *ep, 5466 const struct sctp_association *asoc, 5467 const union sctp_subtype type, 5468 void *arg, 5469 struct sctp_cmd_seq *commands) 5470 { 5471 struct sctp_chunk *chunk = arg; 5472 5473 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5474 return SCTP_DISPOSITION_CONSUME; 5475 } 5476 5477 /* 5478 * Ignore the primitive event 5479 * 5480 * The return value is the disposition of the primitive. 5481 */ 5482 enum sctp_disposition sctp_sf_ignore_primitive( 5483 struct net *net, 5484 const struct sctp_endpoint *ep, 5485 const struct sctp_association *asoc, 5486 const union sctp_subtype type, 5487 void *arg, 5488 struct sctp_cmd_seq *commands) 5489 { 5490 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5491 type.primitive); 5492 5493 return SCTP_DISPOSITION_DISCARD; 5494 } 5495 5496 /*************************************************************************** 5497 * These are the state functions for the OTHER events. 5498 ***************************************************************************/ 5499 5500 /* 5501 * When the SCTP stack has no more user data to send or retransmit, this 5502 * notification is given to the user. Also, at the time when a user app 5503 * subscribes to this event, if there is no data to be sent or 5504 * retransmit, the stack will immediately send up this notification. 5505 */ 5506 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5507 struct net *net, 5508 const struct sctp_endpoint *ep, 5509 const struct sctp_association *asoc, 5510 const union sctp_subtype type, 5511 void *arg, 5512 struct sctp_cmd_seq *commands) 5513 { 5514 struct sctp_ulpevent *event; 5515 5516 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5517 if (!event) 5518 return SCTP_DISPOSITION_NOMEM; 5519 5520 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5521 5522 return SCTP_DISPOSITION_CONSUME; 5523 } 5524 5525 /* 5526 * Start the shutdown negotiation. 5527 * 5528 * From Section 9.2: 5529 * Once all its outstanding data has been acknowledged, the endpoint 5530 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5531 * TSN Ack field the last sequential TSN it has received from the peer. 5532 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5533 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5534 * with the updated last sequential TSN received from its peer. 5535 * 5536 * The return value is the disposition. 5537 */ 5538 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5539 struct net *net, 5540 const struct sctp_endpoint *ep, 5541 const struct sctp_association *asoc, 5542 const union sctp_subtype type, 5543 void *arg, 5544 struct sctp_cmd_seq *commands) 5545 { 5546 struct sctp_chunk *reply; 5547 5548 /* Once all its outstanding data has been acknowledged, the 5549 * endpoint shall send a SHUTDOWN chunk to its peer including 5550 * in the Cumulative TSN Ack field the last sequential TSN it 5551 * has received from the peer. 5552 */ 5553 reply = sctp_make_shutdown(asoc, arg); 5554 if (!reply) 5555 goto nomem; 5556 5557 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5558 * T2-shutdown timer. 5559 */ 5560 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5561 5562 /* It shall then start the T2-shutdown timer */ 5563 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5564 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5565 5566 /* RFC 4960 Section 9.2 5567 * The sender of the SHUTDOWN MAY also start an overall guard timer 5568 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5569 */ 5570 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5571 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5572 5573 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5574 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5575 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5576 5577 /* and enter the SHUTDOWN-SENT state. */ 5578 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5579 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5580 5581 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5582 * 5583 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5584 * or SHUTDOWN-ACK. 5585 */ 5586 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5587 5588 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5589 5590 return SCTP_DISPOSITION_CONSUME; 5591 5592 nomem: 5593 return SCTP_DISPOSITION_NOMEM; 5594 } 5595 5596 /* 5597 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5598 * 5599 * From Section 9.2: 5600 * 5601 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5602 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5603 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5604 * endpoint must re-send the SHUTDOWN ACK. 5605 * 5606 * The return value is the disposition. 5607 */ 5608 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5609 struct net *net, 5610 const struct sctp_endpoint *ep, 5611 const struct sctp_association *asoc, 5612 const union sctp_subtype type, 5613 void *arg, 5614 struct sctp_cmd_seq *commands) 5615 { 5616 struct sctp_chunk *chunk = arg; 5617 struct sctp_chunk *reply; 5618 5619 /* There are 2 ways of getting here: 5620 * 1) called in response to a SHUTDOWN chunk 5621 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5622 * 5623 * For the case (2), the arg parameter is set to NULL. We need 5624 * to check that we have a chunk before accessing it's fields. 5625 */ 5626 if (chunk) { 5627 if (!sctp_vtag_verify(chunk, asoc)) 5628 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5629 commands); 5630 5631 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5632 if (!sctp_chunk_length_valid( 5633 chunk, sizeof(struct sctp_shutdown_chunk))) 5634 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5635 arg, commands); 5636 } 5637 5638 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5639 * shall send a SHUTDOWN ACK ... 5640 */ 5641 reply = sctp_make_shutdown_ack(asoc, chunk); 5642 if (!reply) 5643 goto nomem; 5644 5645 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5646 * the T2-shutdown timer. 5647 */ 5648 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5649 5650 /* and start/restart a T2-shutdown timer of its own, */ 5651 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5652 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5653 5654 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5655 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5656 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5657 5658 /* Enter the SHUTDOWN-ACK-SENT state. */ 5659 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5660 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5661 5662 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5663 * 5664 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5665 * or SHUTDOWN-ACK. 5666 */ 5667 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5668 5669 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5670 5671 return SCTP_DISPOSITION_CONSUME; 5672 5673 nomem: 5674 return SCTP_DISPOSITION_NOMEM; 5675 } 5676 5677 /* 5678 * Ignore the event defined as other 5679 * 5680 * The return value is the disposition of the event. 5681 */ 5682 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5683 const struct sctp_endpoint *ep, 5684 const struct sctp_association *asoc, 5685 const union sctp_subtype type, 5686 void *arg, 5687 struct sctp_cmd_seq *commands) 5688 { 5689 pr_debug("%s: the event other type:%d is ignored\n", 5690 __func__, type.other); 5691 5692 return SCTP_DISPOSITION_DISCARD; 5693 } 5694 5695 /************************************************************ 5696 * These are the state functions for handling timeout events. 5697 ************************************************************/ 5698 5699 /* 5700 * RTX Timeout 5701 * 5702 * Section: 6.3.3 Handle T3-rtx Expiration 5703 * 5704 * Whenever the retransmission timer T3-rtx expires for a destination 5705 * address, do the following: 5706 * [See below] 5707 * 5708 * The return value is the disposition of the chunk. 5709 */ 5710 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5711 const struct sctp_endpoint *ep, 5712 const struct sctp_association *asoc, 5713 const union sctp_subtype type, 5714 void *arg, 5715 struct sctp_cmd_seq *commands) 5716 { 5717 struct sctp_transport *transport = arg; 5718 5719 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5720 5721 if (asoc->overall_error_count >= asoc->max_retrans) { 5722 if (asoc->peer.zero_window_announced && 5723 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5724 /* 5725 * We are here likely because the receiver had its rwnd 5726 * closed for a while and we have not been able to 5727 * transmit the locally queued data within the maximum 5728 * retransmission attempts limit. Start the T5 5729 * shutdown guard timer to give the receiver one last 5730 * chance and some additional time to recover before 5731 * aborting. 5732 */ 5733 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5734 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5735 } else { 5736 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5737 SCTP_ERROR(ETIMEDOUT)); 5738 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5739 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5740 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5741 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5742 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5743 return SCTP_DISPOSITION_DELETE_TCB; 5744 } 5745 } 5746 5747 /* E1) For the destination address for which the timer 5748 * expires, adjust its ssthresh with rules defined in Section 5749 * 7.2.3 and set the cwnd <- MTU. 5750 */ 5751 5752 /* E2) For the destination address for which the timer 5753 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5754 * maximum value discussed in rule C7 above (RTO.max) may be 5755 * used to provide an upper bound to this doubling operation. 5756 */ 5757 5758 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5759 * outstanding DATA chunks for the address for which the 5760 * T3-rtx has expired will fit into a single packet, subject 5761 * to the MTU constraint for the path corresponding to the 5762 * destination transport address to which the retransmission 5763 * is being sent (this may be different from the address for 5764 * which the timer expires [see Section 6.4]). Call this 5765 * value K. Bundle and retransmit those K DATA chunks in a 5766 * single packet to the destination endpoint. 5767 * 5768 * Note: Any DATA chunks that were sent to the address for 5769 * which the T3-rtx timer expired but did not fit in one MTU 5770 * (rule E3 above), should be marked for retransmission and 5771 * sent as soon as cwnd allows (normally when a SACK arrives). 5772 */ 5773 5774 /* Do some failure management (Section 8.2). */ 5775 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5776 5777 /* NB: Rules E4 and F1 are implicit in R1. */ 5778 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5779 5780 return SCTP_DISPOSITION_CONSUME; 5781 } 5782 5783 /* 5784 * Generate delayed SACK on timeout 5785 * 5786 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5787 * 5788 * The guidelines on delayed acknowledgement algorithm specified in 5789 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5790 * acknowledgement SHOULD be generated for at least every second packet 5791 * (not every second DATA chunk) received, and SHOULD be generated 5792 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5793 * some situations it may be beneficial for an SCTP transmitter to be 5794 * more conservative than the algorithms detailed in this document 5795 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5796 * the following algorithms allow. 5797 */ 5798 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5799 const struct sctp_endpoint *ep, 5800 const struct sctp_association *asoc, 5801 const union sctp_subtype type, 5802 void *arg, 5803 struct sctp_cmd_seq *commands) 5804 { 5805 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5806 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5807 return SCTP_DISPOSITION_CONSUME; 5808 } 5809 5810 /* 5811 * sctp_sf_t1_init_timer_expire 5812 * 5813 * Section: 4 Note: 2 5814 * Verification Tag: 5815 * Inputs 5816 * (endpoint, asoc) 5817 * 5818 * RFC 2960 Section 4 Notes 5819 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5820 * and re-start the T1-init timer without changing state. This MUST 5821 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5822 * endpoint MUST abort the initialization process and report the 5823 * error to SCTP user. 5824 * 5825 * Outputs 5826 * (timers, events) 5827 * 5828 */ 5829 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5830 struct net *net, 5831 const struct sctp_endpoint *ep, 5832 const struct sctp_association *asoc, 5833 const union sctp_subtype type, 5834 void *arg, 5835 struct sctp_cmd_seq *commands) 5836 { 5837 int attempts = asoc->init_err_counter + 1; 5838 struct sctp_chunk *repl = NULL; 5839 struct sctp_bind_addr *bp; 5840 5841 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5842 5843 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5844 5845 if (attempts <= asoc->max_init_attempts) { 5846 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5847 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5848 if (!repl) 5849 return SCTP_DISPOSITION_NOMEM; 5850 5851 /* Choose transport for INIT. */ 5852 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5853 SCTP_CHUNK(repl)); 5854 5855 /* Issue a sideeffect to do the needed accounting. */ 5856 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5857 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5858 5859 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5860 } else { 5861 pr_debug("%s: giving up on INIT, attempts:%d " 5862 "max_init_attempts:%d\n", __func__, attempts, 5863 asoc->max_init_attempts); 5864 5865 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5866 SCTP_ERROR(ETIMEDOUT)); 5867 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5868 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5869 return SCTP_DISPOSITION_DELETE_TCB; 5870 } 5871 5872 return SCTP_DISPOSITION_CONSUME; 5873 } 5874 5875 /* 5876 * sctp_sf_t1_cookie_timer_expire 5877 * 5878 * Section: 4 Note: 2 5879 * Verification Tag: 5880 * Inputs 5881 * (endpoint, asoc) 5882 * 5883 * RFC 2960 Section 4 Notes 5884 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5885 * COOKIE ECHO and re-start the T1-cookie timer without changing 5886 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5887 * After that, the endpoint MUST abort the initialization process and 5888 * report the error to SCTP user. 5889 * 5890 * Outputs 5891 * (timers, events) 5892 * 5893 */ 5894 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5895 struct net *net, 5896 const struct sctp_endpoint *ep, 5897 const struct sctp_association *asoc, 5898 const union sctp_subtype type, 5899 void *arg, 5900 struct sctp_cmd_seq *commands) 5901 { 5902 int attempts = asoc->init_err_counter + 1; 5903 struct sctp_chunk *repl = NULL; 5904 5905 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5906 5907 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5908 5909 if (attempts <= asoc->max_init_attempts) { 5910 repl = sctp_make_cookie_echo(asoc, NULL); 5911 if (!repl) 5912 return SCTP_DISPOSITION_NOMEM; 5913 5914 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5915 SCTP_CHUNK(repl)); 5916 /* Issue a sideeffect to do the needed accounting. */ 5917 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5918 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5919 5920 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5921 } else { 5922 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5923 SCTP_ERROR(ETIMEDOUT)); 5924 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5925 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5926 return SCTP_DISPOSITION_DELETE_TCB; 5927 } 5928 5929 return SCTP_DISPOSITION_CONSUME; 5930 } 5931 5932 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5933 * with the updated last sequential TSN received from its peer. 5934 * 5935 * An endpoint should limit the number of retransmissions of the 5936 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5937 * If this threshold is exceeded the endpoint should destroy the TCB and 5938 * MUST report the peer endpoint unreachable to the upper layer (and 5939 * thus the association enters the CLOSED state). The reception of any 5940 * packet from its peer (i.e. as the peer sends all of its queued DATA 5941 * chunks) should clear the endpoint's retransmission count and restart 5942 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5943 * all of its queued DATA chunks that have not yet been sent. 5944 */ 5945 enum sctp_disposition sctp_sf_t2_timer_expire( 5946 struct net *net, 5947 const struct sctp_endpoint *ep, 5948 const struct sctp_association *asoc, 5949 const union sctp_subtype type, 5950 void *arg, 5951 struct sctp_cmd_seq *commands) 5952 { 5953 struct sctp_chunk *reply = NULL; 5954 5955 pr_debug("%s: timer T2 expired\n", __func__); 5956 5957 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5958 5959 ((struct sctp_association *)asoc)->shutdown_retries++; 5960 5961 if (asoc->overall_error_count >= asoc->max_retrans) { 5962 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5963 SCTP_ERROR(ETIMEDOUT)); 5964 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5965 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5966 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5967 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5968 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5969 return SCTP_DISPOSITION_DELETE_TCB; 5970 } 5971 5972 switch (asoc->state) { 5973 case SCTP_STATE_SHUTDOWN_SENT: 5974 reply = sctp_make_shutdown(asoc, NULL); 5975 break; 5976 5977 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5978 reply = sctp_make_shutdown_ack(asoc, NULL); 5979 break; 5980 5981 default: 5982 BUG(); 5983 break; 5984 } 5985 5986 if (!reply) 5987 goto nomem; 5988 5989 /* Do some failure management (Section 8.2). 5990 * If we remove the transport an SHUTDOWN was last sent to, don't 5991 * do failure management. 5992 */ 5993 if (asoc->shutdown_last_sent_to) 5994 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5995 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5996 5997 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5998 * the T2-shutdown timer. 5999 */ 6000 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6001 6002 /* Restart the T2-shutdown timer. */ 6003 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6004 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6005 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6006 return SCTP_DISPOSITION_CONSUME; 6007 6008 nomem: 6009 return SCTP_DISPOSITION_NOMEM; 6010 } 6011 6012 /* 6013 * ADDIP Section 4.1 ASCONF CHunk Procedures 6014 * If the T4 RTO timer expires the endpoint should do B1 to B5 6015 */ 6016 enum sctp_disposition sctp_sf_t4_timer_expire( 6017 struct net *net, 6018 const struct sctp_endpoint *ep, 6019 const struct sctp_association *asoc, 6020 const union sctp_subtype type, 6021 void *arg, 6022 struct sctp_cmd_seq *commands) 6023 { 6024 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6025 struct sctp_transport *transport = chunk->transport; 6026 6027 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6028 6029 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6030 * detection on the appropriate destination address as defined in 6031 * RFC2960 [5] section 8.1 and 8.2. 6032 */ 6033 if (transport) 6034 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6035 SCTP_TRANSPORT(transport)); 6036 6037 /* Reconfig T4 timer and transport. */ 6038 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6039 6040 /* ADDIP 4.1 B2) Increment the association error counters and perform 6041 * endpoint failure detection on the association as defined in 6042 * RFC2960 [5] section 8.1 and 8.2. 6043 * association error counter is incremented in SCTP_CMD_STRIKE. 6044 */ 6045 if (asoc->overall_error_count >= asoc->max_retrans) { 6046 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6047 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6048 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6049 SCTP_ERROR(ETIMEDOUT)); 6050 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6051 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6052 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6053 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6054 return SCTP_DISPOSITION_ABORT; 6055 } 6056 6057 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6058 * the ASCONF chunk was sent by doubling the RTO timer value. 6059 * This is done in SCTP_CMD_STRIKE. 6060 */ 6061 6062 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6063 * choose an alternate destination address (please refer to RFC2960 6064 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6065 * chunk, it MUST be the same (including its serial number) as the last 6066 * ASCONF sent. 6067 */ 6068 sctp_chunk_hold(asoc->addip_last_asconf); 6069 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6070 SCTP_CHUNK(asoc->addip_last_asconf)); 6071 6072 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6073 * destination is selected, then the RTO used will be that of the new 6074 * destination address. 6075 */ 6076 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6077 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6078 6079 return SCTP_DISPOSITION_CONSUME; 6080 } 6081 6082 /* sctpimpguide-05 Section 2.12.2 6083 * The sender of the SHUTDOWN MAY also start an overall guard timer 6084 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6085 * At the expiration of this timer the sender SHOULD abort the association 6086 * by sending an ABORT chunk. 6087 */ 6088 enum sctp_disposition sctp_sf_t5_timer_expire( 6089 struct net *net, 6090 const struct sctp_endpoint *ep, 6091 const struct sctp_association *asoc, 6092 const union sctp_subtype type, 6093 void *arg, 6094 struct sctp_cmd_seq *commands) 6095 { 6096 struct sctp_chunk *reply = NULL; 6097 6098 pr_debug("%s: timer T5 expired\n", __func__); 6099 6100 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6101 6102 reply = sctp_make_abort(asoc, NULL, 0); 6103 if (!reply) 6104 goto nomem; 6105 6106 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6107 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6108 SCTP_ERROR(ETIMEDOUT)); 6109 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6110 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6111 6112 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6113 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6114 6115 return SCTP_DISPOSITION_DELETE_TCB; 6116 nomem: 6117 return SCTP_DISPOSITION_NOMEM; 6118 } 6119 6120 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6121 * the association is automatically closed by starting the shutdown process. 6122 * The work that needs to be done is same as when SHUTDOWN is initiated by 6123 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6124 */ 6125 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6126 struct net *net, 6127 const struct sctp_endpoint *ep, 6128 const struct sctp_association *asoc, 6129 const union sctp_subtype type, 6130 void *arg, 6131 struct sctp_cmd_seq *commands) 6132 { 6133 enum sctp_disposition disposition; 6134 6135 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6136 6137 /* From 9.2 Shutdown of an Association 6138 * Upon receipt of the SHUTDOWN primitive from its upper 6139 * layer, the endpoint enters SHUTDOWN-PENDING state and 6140 * remains there until all outstanding data has been 6141 * acknowledged by its peer. The endpoint accepts no new data 6142 * from its upper layer, but retransmits data to the far end 6143 * if necessary to fill gaps. 6144 */ 6145 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6146 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6147 6148 disposition = SCTP_DISPOSITION_CONSUME; 6149 if (sctp_outq_is_empty(&asoc->outqueue)) { 6150 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6151 NULL, commands); 6152 } 6153 6154 return disposition; 6155 } 6156 6157 /***************************************************************************** 6158 * These are sa state functions which could apply to all types of events. 6159 ****************************************************************************/ 6160 6161 /* 6162 * This table entry is not implemented. 6163 * 6164 * Inputs 6165 * (endpoint, asoc, chunk) 6166 * 6167 * The return value is the disposition of the chunk. 6168 */ 6169 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6170 const struct sctp_endpoint *ep, 6171 const struct sctp_association *asoc, 6172 const union sctp_subtype type, 6173 void *arg, struct sctp_cmd_seq *commands) 6174 { 6175 return SCTP_DISPOSITION_NOT_IMPL; 6176 } 6177 6178 /* 6179 * This table entry represents a bug. 6180 * 6181 * Inputs 6182 * (endpoint, asoc, chunk) 6183 * 6184 * The return value is the disposition of the chunk. 6185 */ 6186 enum sctp_disposition sctp_sf_bug(struct net *net, 6187 const struct sctp_endpoint *ep, 6188 const struct sctp_association *asoc, 6189 const union sctp_subtype type, 6190 void *arg, struct sctp_cmd_seq *commands) 6191 { 6192 return SCTP_DISPOSITION_BUG; 6193 } 6194 6195 /* 6196 * This table entry represents the firing of a timer in the wrong state. 6197 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6198 * when the association is in the wrong state. This event should 6199 * be ignored, so as to prevent any rearming of the timer. 6200 * 6201 * Inputs 6202 * (endpoint, asoc, chunk) 6203 * 6204 * The return value is the disposition of the chunk. 6205 */ 6206 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6207 const struct sctp_endpoint *ep, 6208 const struct sctp_association *asoc, 6209 const union sctp_subtype type, 6210 void *arg, 6211 struct sctp_cmd_seq *commands) 6212 { 6213 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6214 6215 return SCTP_DISPOSITION_CONSUME; 6216 } 6217 6218 /******************************************************************** 6219 * 2nd Level Abstractions 6220 ********************************************************************/ 6221 6222 /* Pull the SACK chunk based on the SACK header. */ 6223 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6224 { 6225 struct sctp_sackhdr *sack; 6226 __u16 num_dup_tsns; 6227 unsigned int len; 6228 __u16 num_blocks; 6229 6230 /* Protect ourselves from reading too far into 6231 * the skb from a bogus sender. 6232 */ 6233 sack = (struct sctp_sackhdr *) chunk->skb->data; 6234 6235 num_blocks = ntohs(sack->num_gap_ack_blocks); 6236 num_dup_tsns = ntohs(sack->num_dup_tsns); 6237 len = sizeof(struct sctp_sackhdr); 6238 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6239 if (len > chunk->skb->len) 6240 return NULL; 6241 6242 skb_pull(chunk->skb, len); 6243 6244 return sack; 6245 } 6246 6247 /* Create an ABORT packet to be sent as a response, with the specified 6248 * error causes. 6249 */ 6250 static struct sctp_packet *sctp_abort_pkt_new( 6251 struct net *net, 6252 const struct sctp_endpoint *ep, 6253 const struct sctp_association *asoc, 6254 struct sctp_chunk *chunk, 6255 const void *payload, size_t paylen) 6256 { 6257 struct sctp_packet *packet; 6258 struct sctp_chunk *abort; 6259 6260 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6261 6262 if (packet) { 6263 /* Make an ABORT. 6264 * The T bit will be set if the asoc is NULL. 6265 */ 6266 abort = sctp_make_abort(asoc, chunk, paylen); 6267 if (!abort) { 6268 sctp_ootb_pkt_free(packet); 6269 return NULL; 6270 } 6271 6272 /* Reflect vtag if T-Bit is set */ 6273 if (sctp_test_T_bit(abort)) 6274 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6275 6276 /* Add specified error causes, i.e., payload, to the 6277 * end of the chunk. 6278 */ 6279 sctp_addto_chunk(abort, paylen, payload); 6280 6281 /* Set the skb to the belonging sock for accounting. */ 6282 abort->skb->sk = ep->base.sk; 6283 6284 sctp_packet_append_chunk(packet, abort); 6285 6286 } 6287 6288 return packet; 6289 } 6290 6291 /* Allocate a packet for responding in the OOTB conditions. */ 6292 static struct sctp_packet *sctp_ootb_pkt_new( 6293 struct net *net, 6294 const struct sctp_association *asoc, 6295 const struct sctp_chunk *chunk) 6296 { 6297 struct sctp_transport *transport; 6298 struct sctp_packet *packet; 6299 __u16 sport, dport; 6300 __u32 vtag; 6301 6302 /* Get the source and destination port from the inbound packet. */ 6303 sport = ntohs(chunk->sctp_hdr->dest); 6304 dport = ntohs(chunk->sctp_hdr->source); 6305 6306 /* The V-tag is going to be the same as the inbound packet if no 6307 * association exists, otherwise, use the peer's vtag. 6308 */ 6309 if (asoc) { 6310 /* Special case the INIT-ACK as there is no peer's vtag 6311 * yet. 6312 */ 6313 switch (chunk->chunk_hdr->type) { 6314 case SCTP_CID_INIT_ACK: 6315 { 6316 struct sctp_initack_chunk *initack; 6317 6318 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6319 vtag = ntohl(initack->init_hdr.init_tag); 6320 break; 6321 } 6322 default: 6323 vtag = asoc->peer.i.init_tag; 6324 break; 6325 } 6326 } else { 6327 /* Special case the INIT and stale COOKIE_ECHO as there is no 6328 * vtag yet. 6329 */ 6330 switch (chunk->chunk_hdr->type) { 6331 case SCTP_CID_INIT: 6332 { 6333 struct sctp_init_chunk *init; 6334 6335 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6336 vtag = ntohl(init->init_hdr.init_tag); 6337 break; 6338 } 6339 default: 6340 vtag = ntohl(chunk->sctp_hdr->vtag); 6341 break; 6342 } 6343 } 6344 6345 /* Make a transport for the bucket, Eliza... */ 6346 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6347 if (!transport) 6348 goto nomem; 6349 6350 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6351 6352 /* Cache a route for the transport with the chunk's destination as 6353 * the source address. 6354 */ 6355 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6356 sctp_sk(net->sctp.ctl_sock)); 6357 6358 packet = &transport->packet; 6359 sctp_packet_init(packet, transport, sport, dport); 6360 sctp_packet_config(packet, vtag, 0); 6361 6362 return packet; 6363 6364 nomem: 6365 return NULL; 6366 } 6367 6368 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6369 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6370 { 6371 sctp_transport_free(packet->transport); 6372 } 6373 6374 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6375 static void sctp_send_stale_cookie_err(struct net *net, 6376 const struct sctp_endpoint *ep, 6377 const struct sctp_association *asoc, 6378 const struct sctp_chunk *chunk, 6379 struct sctp_cmd_seq *commands, 6380 struct sctp_chunk *err_chunk) 6381 { 6382 struct sctp_packet *packet; 6383 6384 if (err_chunk) { 6385 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6386 if (packet) { 6387 struct sctp_signed_cookie *cookie; 6388 6389 /* Override the OOTB vtag from the cookie. */ 6390 cookie = chunk->subh.cookie_hdr; 6391 packet->vtag = cookie->c.peer_vtag; 6392 6393 /* Set the skb to the belonging sock for accounting. */ 6394 err_chunk->skb->sk = ep->base.sk; 6395 sctp_packet_append_chunk(packet, err_chunk); 6396 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6397 SCTP_PACKET(packet)); 6398 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6399 } else 6400 sctp_chunk_free (err_chunk); 6401 } 6402 } 6403 6404 6405 /* Process a data chunk */ 6406 static int sctp_eat_data(const struct sctp_association *asoc, 6407 struct sctp_chunk *chunk, 6408 struct sctp_cmd_seq *commands) 6409 { 6410 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6411 struct sock *sk = asoc->base.sk; 6412 struct net *net = sock_net(sk); 6413 struct sctp_datahdr *data_hdr; 6414 struct sctp_chunk *err; 6415 enum sctp_verb deliver; 6416 size_t datalen; 6417 __u32 tsn; 6418 int tmp; 6419 6420 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6421 chunk->subh.data_hdr = data_hdr; 6422 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6423 6424 tsn = ntohl(data_hdr->tsn); 6425 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6426 6427 /* ASSERT: Now skb->data is really the user data. */ 6428 6429 /* Process ECN based congestion. 6430 * 6431 * Since the chunk structure is reused for all chunks within 6432 * a packet, we use ecn_ce_done to track if we've already 6433 * done CE processing for this packet. 6434 * 6435 * We need to do ECN processing even if we plan to discard the 6436 * chunk later. 6437 */ 6438 6439 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6440 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6441 chunk->ecn_ce_done = 1; 6442 6443 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6444 /* Do real work as sideffect. */ 6445 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6446 SCTP_U32(tsn)); 6447 } 6448 } 6449 6450 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6451 if (tmp < 0) { 6452 /* The TSN is too high--silently discard the chunk and 6453 * count on it getting retransmitted later. 6454 */ 6455 if (chunk->asoc) 6456 chunk->asoc->stats.outofseqtsns++; 6457 return SCTP_IERROR_HIGH_TSN; 6458 } else if (tmp > 0) { 6459 /* This is a duplicate. Record it. */ 6460 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6461 return SCTP_IERROR_DUP_TSN; 6462 } 6463 6464 /* This is a new TSN. */ 6465 6466 /* Discard if there is no room in the receive window. 6467 * Actually, allow a little bit of overflow (up to a MTU). 6468 */ 6469 datalen = ntohs(chunk->chunk_hdr->length); 6470 datalen -= sctp_datachk_len(&asoc->stream); 6471 6472 deliver = SCTP_CMD_CHUNK_ULP; 6473 6474 /* Think about partial delivery. */ 6475 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6476 6477 /* Even if we don't accept this chunk there is 6478 * memory pressure. 6479 */ 6480 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6481 } 6482 6483 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6484 * seems a bit troublesome in that frag_point varies based on 6485 * PMTU. In cases, such as loopback, this might be a rather 6486 * large spill over. 6487 */ 6488 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6489 (datalen > asoc->rwnd + asoc->frag_point))) { 6490 6491 /* If this is the next TSN, consider reneging to make 6492 * room. Note: Playing nice with a confused sender. A 6493 * malicious sender can still eat up all our buffer 6494 * space and in the future we may want to detect and 6495 * do more drastic reneging. 6496 */ 6497 if (sctp_tsnmap_has_gap(map) && 6498 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6499 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6500 deliver = SCTP_CMD_RENEGE; 6501 } else { 6502 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6503 __func__, tsn, datalen, asoc->rwnd); 6504 6505 return SCTP_IERROR_IGNORE_TSN; 6506 } 6507 } 6508 6509 /* 6510 * Also try to renege to limit our memory usage in the event that 6511 * we are under memory pressure 6512 * If we can't renege, don't worry about it, the sk_rmem_schedule 6513 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6514 * memory usage too much 6515 */ 6516 if (sk_under_memory_pressure(sk)) { 6517 if (sctp_tsnmap_has_gap(map) && 6518 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6519 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6520 __func__, tsn); 6521 deliver = SCTP_CMD_RENEGE; 6522 } else { 6523 sk_mem_reclaim(sk); 6524 } 6525 } 6526 6527 /* 6528 * Section 3.3.10.9 No User Data (9) 6529 * 6530 * Cause of error 6531 * --------------- 6532 * No User Data: This error cause is returned to the originator of a 6533 * DATA chunk if a received DATA chunk has no user data. 6534 */ 6535 if (unlikely(0 == datalen)) { 6536 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6537 if (err) { 6538 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6539 SCTP_CHUNK(err)); 6540 } 6541 /* We are going to ABORT, so we might as well stop 6542 * processing the rest of the chunks in the packet. 6543 */ 6544 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6545 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6546 SCTP_ERROR(ECONNABORTED)); 6547 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6548 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6549 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6550 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6551 return SCTP_IERROR_NO_DATA; 6552 } 6553 6554 chunk->data_accepted = 1; 6555 6556 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6557 * if we renege and the chunk arrives again. 6558 */ 6559 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6560 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6561 if (chunk->asoc) 6562 chunk->asoc->stats.iuodchunks++; 6563 } else { 6564 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6565 if (chunk->asoc) 6566 chunk->asoc->stats.iodchunks++; 6567 } 6568 6569 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6570 * 6571 * If an endpoint receive a DATA chunk with an invalid stream 6572 * identifier, it shall acknowledge the reception of the DATA chunk 6573 * following the normal procedure, immediately send an ERROR chunk 6574 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6575 * and discard the DATA chunk. 6576 */ 6577 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6578 /* Mark tsn as received even though we drop it */ 6579 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6580 6581 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6582 &data_hdr->stream, 6583 sizeof(data_hdr->stream), 6584 sizeof(u16)); 6585 if (err) 6586 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6587 SCTP_CHUNK(err)); 6588 return SCTP_IERROR_BAD_STREAM; 6589 } 6590 6591 /* Check to see if the SSN is possible for this TSN. 6592 * The biggest gap we can record is 4K wide. Since SSNs wrap 6593 * at an unsigned short, there is no way that an SSN can 6594 * wrap and for a valid TSN. We can simply check if the current 6595 * SSN is smaller then the next expected one. If it is, it wrapped 6596 * and is invalid. 6597 */ 6598 if (!asoc->stream.si->validate_data(chunk)) 6599 return SCTP_IERROR_PROTO_VIOLATION; 6600 6601 /* Send the data up to the user. Note: Schedule the 6602 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6603 * chunk needs the updated rwnd. 6604 */ 6605 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6606 6607 return SCTP_IERROR_NO_ERROR; 6608 } 6609