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