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