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