1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <lksctp-developers@lists.sourceforge.net> 32 * 33 * Or submit a bug report through the following website: 34 * http://www.sf.net/projects/lksctp 35 * 36 * Written or modified by: 37 * La Monte H.P. Yarroll <piggy@acm.org> 38 * Karl Knutson <karl@athena.chicago.il.us> 39 * Mathew Kotowsky <kotowsky@sctp.org> 40 * Sridhar Samudrala <samudrala@us.ibm.com> 41 * Jon Grimm <jgrimm@us.ibm.com> 42 * Hui Huang <hui.huang@nokia.com> 43 * Dajiang Zhang <dajiang.zhang@nokia.com> 44 * Daisy Chang <daisyc@us.ibm.com> 45 * Ardelle Fan <ardelle.fan@intel.com> 46 * Ryan Layer <rmlayer@us.ibm.com> 47 * Kevin Gao <kevin.gao@intel.com> 48 * 49 * Any bugs reported given to us we will try to fix... any fixes shared will 50 * be incorporated into the next SCTP release. 51 */ 52 53 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 54 55 #include <linux/types.h> 56 #include <linux/kernel.h> 57 #include <linux/ip.h> 58 #include <linux/ipv6.h> 59 #include <linux/net.h> 60 #include <linux/inet.h> 61 #include <linux/slab.h> 62 #include <net/sock.h> 63 #include <net/inet_ecn.h> 64 #include <linux/skbuff.h> 65 #include <net/sctp/sctp.h> 66 #include <net/sctp/sm.h> 67 #include <net/sctp/structs.h> 68 69 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 70 const struct sctp_association *asoc, 71 struct sctp_chunk *chunk, 72 const void *payload, 73 size_t paylen); 74 static int sctp_eat_data(const struct sctp_association *asoc, 75 struct sctp_chunk *chunk, 76 sctp_cmd_seq_t *commands); 77 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 78 const struct sctp_chunk *chunk); 79 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 80 const struct sctp_association *asoc, 81 const struct sctp_chunk *chunk, 82 sctp_cmd_seq_t *commands, 83 struct sctp_chunk *err_chunk); 84 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 85 const struct sctp_association *asoc, 86 const sctp_subtype_t type, 87 void *arg, 88 sctp_cmd_seq_t *commands); 89 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 90 const struct sctp_association *asoc, 91 const sctp_subtype_t type, 92 void *arg, 93 sctp_cmd_seq_t *commands); 94 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const sctp_subtype_t type, 97 void *arg, 98 sctp_cmd_seq_t *commands); 99 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 100 101 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 102 __be16 error, int sk_err, 103 const struct sctp_association *asoc, 104 struct sctp_transport *transport); 105 106 static sctp_disposition_t sctp_sf_abort_violation( 107 const struct sctp_endpoint *ep, 108 const struct sctp_association *asoc, 109 void *arg, 110 sctp_cmd_seq_t *commands, 111 const __u8 *payload, 112 const size_t paylen); 113 114 static sctp_disposition_t sctp_sf_violation_chunklen( 115 const struct sctp_endpoint *ep, 116 const struct sctp_association *asoc, 117 const sctp_subtype_t type, 118 void *arg, 119 sctp_cmd_seq_t *commands); 120 121 static sctp_disposition_t sctp_sf_violation_paramlen( 122 const struct sctp_endpoint *ep, 123 const struct sctp_association *asoc, 124 const sctp_subtype_t type, 125 void *arg, void *ext, 126 sctp_cmd_seq_t *commands); 127 128 static sctp_disposition_t sctp_sf_violation_ctsn( 129 const struct sctp_endpoint *ep, 130 const struct sctp_association *asoc, 131 const sctp_subtype_t type, 132 void *arg, 133 sctp_cmd_seq_t *commands); 134 135 static sctp_disposition_t sctp_sf_violation_chunk( 136 const struct sctp_endpoint *ep, 137 const struct sctp_association *asoc, 138 const sctp_subtype_t type, 139 void *arg, 140 sctp_cmd_seq_t *commands); 141 142 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 143 const struct sctp_association *asoc, 144 const sctp_subtype_t type, 145 struct sctp_chunk *chunk); 146 147 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 148 const struct sctp_association *asoc, 149 const sctp_subtype_t type, 150 void *arg, 151 sctp_cmd_seq_t *commands); 152 153 /* Small helper function that checks if the chunk length 154 * is of the appropriate length. The 'required_length' argument 155 * is set to be the size of a specific chunk we are testing. 156 * Return Values: 1 = Valid length 157 * 0 = Invalid length 158 * 159 */ 160 static inline int 161 sctp_chunk_length_valid(struct sctp_chunk *chunk, 162 __u16 required_length) 163 { 164 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 165 166 if (unlikely(chunk_length < required_length)) 167 return 0; 168 169 return 1; 170 } 171 172 /********************************************************** 173 * These are the state functions for handling chunk events. 174 **********************************************************/ 175 176 /* 177 * Process the final SHUTDOWN COMPLETE. 178 * 179 * Section: 4 (C) (diagram), 9.2 180 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 181 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 182 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 183 * should stop the T2-shutdown timer and remove all knowledge of the 184 * association (and thus the association enters the CLOSED state). 185 * 186 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 187 * C) Rules for packet carrying SHUTDOWN COMPLETE: 188 * ... 189 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 190 * if the Verification Tag field of the packet matches its own tag and 191 * the T bit is not set 192 * OR 193 * it is set to its peer's tag and the T bit is set in the Chunk 194 * Flags. 195 * Otherwise, the receiver MUST silently discard the packet 196 * and take no further action. An endpoint MUST ignore the 197 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 198 * 199 * Inputs 200 * (endpoint, asoc, chunk) 201 * 202 * Outputs 203 * (asoc, reply_msg, msg_up, timers, counters) 204 * 205 * The return value is the disposition of the chunk. 206 */ 207 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, 208 const struct sctp_association *asoc, 209 const sctp_subtype_t type, 210 void *arg, 211 sctp_cmd_seq_t *commands) 212 { 213 struct sctp_chunk *chunk = arg; 214 struct sctp_ulpevent *ev; 215 216 if (!sctp_vtag_verify_either(chunk, asoc)) 217 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 218 219 /* RFC 2960 6.10 Bundling 220 * 221 * An endpoint MUST NOT bundle INIT, INIT ACK or 222 * SHUTDOWN COMPLETE with any other chunks. 223 */ 224 if (!chunk->singleton) 225 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 226 227 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 228 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 229 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 230 commands); 231 232 /* RFC 2960 10.2 SCTP-to-ULP 233 * 234 * H) SHUTDOWN COMPLETE notification 235 * 236 * When SCTP completes the shutdown procedures (section 9.2) this 237 * notification is passed to the upper layer. 238 */ 239 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 240 0, 0, 0, NULL, GFP_ATOMIC); 241 if (ev) 242 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 243 SCTP_ULPEVENT(ev)); 244 245 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 246 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 247 * not the chunk should be discarded. If the endpoint is in 248 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 249 * T2-shutdown timer and remove all knowledge of the 250 * association (and thus the association enters the CLOSED 251 * state). 252 */ 253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 254 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 255 256 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 257 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 258 259 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 260 SCTP_STATE(SCTP_STATE_CLOSED)); 261 262 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 263 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 264 265 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 266 267 return SCTP_DISPOSITION_DELETE_TCB; 268 } 269 270 /* 271 * Respond to a normal INIT chunk. 272 * We are the side that is being asked for an association. 273 * 274 * Section: 5.1 Normal Establishment of an Association, B 275 * B) "Z" shall respond immediately with an INIT ACK chunk. The 276 * destination IP address of the INIT ACK MUST be set to the source 277 * IP address of the INIT to which this INIT ACK is responding. In 278 * the response, besides filling in other parameters, "Z" must set the 279 * Verification Tag field to Tag_A, and also provide its own 280 * Verification Tag (Tag_Z) in the Initiate Tag field. 281 * 282 * Verification Tag: Must be 0. 283 * 284 * Inputs 285 * (endpoint, asoc, chunk) 286 * 287 * Outputs 288 * (asoc, reply_msg, msg_up, timers, counters) 289 * 290 * The return value is the disposition of the chunk. 291 */ 292 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 293 const struct sctp_association *asoc, 294 const sctp_subtype_t type, 295 void *arg, 296 sctp_cmd_seq_t *commands) 297 { 298 struct sctp_chunk *chunk = arg; 299 struct sctp_chunk *repl; 300 struct sctp_association *new_asoc; 301 struct sctp_chunk *err_chunk; 302 struct sctp_packet *packet; 303 sctp_unrecognized_param_t *unk_param; 304 int len; 305 306 /* 6.10 Bundling 307 * An endpoint MUST NOT bundle INIT, INIT ACK or 308 * SHUTDOWN COMPLETE with any other chunks. 309 * 310 * IG Section 2.11.2 311 * Furthermore, we require that the receiver of an INIT chunk MUST 312 * enforce these rules by silently discarding an arriving packet 313 * with an INIT chunk that is bundled with other chunks. 314 */ 315 if (!chunk->singleton) 316 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 317 318 /* If the packet is an OOTB packet which is temporarily on the 319 * control endpoint, respond with an ABORT. 320 */ 321 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) { 322 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 323 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 324 } 325 326 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 327 * Tag. 328 */ 329 if (chunk->sctp_hdr->vtag != 0) 330 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 331 332 /* Make sure that the INIT chunk has a valid length. 333 * Normally, this would cause an ABORT with a Protocol Violation 334 * error, but since we don't have an association, we'll 335 * just discard the packet. 336 */ 337 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 338 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 339 340 /* If the INIT is coming toward a closing socket, we'll send back 341 * and ABORT. Essentially, this catches the race of INIT being 342 * backloged to the socket at the same time as the user isses close(). 343 * Since the socket and all its associations are going away, we 344 * can treat this OOTB 345 */ 346 if (sctp_sstate(ep->base.sk, CLOSING)) 347 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 348 349 /* Verify the INIT chunk before processing it. */ 350 err_chunk = NULL; 351 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 352 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 353 &err_chunk)) { 354 /* This chunk contains fatal error. It is to be discarded. 355 * Send an ABORT, with causes if there is any. 356 */ 357 if (err_chunk) { 358 packet = sctp_abort_pkt_new(ep, asoc, arg, 359 (__u8 *)(err_chunk->chunk_hdr) + 360 sizeof(sctp_chunkhdr_t), 361 ntohs(err_chunk->chunk_hdr->length) - 362 sizeof(sctp_chunkhdr_t)); 363 364 sctp_chunk_free(err_chunk); 365 366 if (packet) { 367 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 368 SCTP_PACKET(packet)); 369 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 370 return SCTP_DISPOSITION_CONSUME; 371 } else { 372 return SCTP_DISPOSITION_NOMEM; 373 } 374 } else { 375 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 376 commands); 377 } 378 } 379 380 /* Grab the INIT header. */ 381 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 382 383 /* Tag the variable length parameters. */ 384 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 385 386 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 387 if (!new_asoc) 388 goto nomem; 389 390 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 391 sctp_scope(sctp_source(chunk)), 392 GFP_ATOMIC) < 0) 393 goto nomem_init; 394 395 /* The call, sctp_process_init(), can fail on memory allocation. */ 396 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 397 (sctp_init_chunk_t *)chunk->chunk_hdr, 398 GFP_ATOMIC)) 399 goto nomem_init; 400 401 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 402 403 /* If there are errors need to be reported for unknown parameters, 404 * make sure to reserve enough room in the INIT ACK for them. 405 */ 406 len = 0; 407 if (err_chunk) 408 len = ntohs(err_chunk->chunk_hdr->length) - 409 sizeof(sctp_chunkhdr_t); 410 411 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 412 if (!repl) 413 goto nomem_init; 414 415 /* If there are errors need to be reported for unknown parameters, 416 * include them in the outgoing INIT ACK as "Unrecognized parameter" 417 * parameter. 418 */ 419 if (err_chunk) { 420 /* Get the "Unrecognized parameter" parameter(s) out of the 421 * ERROR chunk generated by sctp_verify_init(). Since the 422 * error cause code for "unknown parameter" and the 423 * "Unrecognized parameter" type is the same, we can 424 * construct the parameters in INIT ACK by copying the 425 * ERROR causes over. 426 */ 427 unk_param = (sctp_unrecognized_param_t *) 428 ((__u8 *)(err_chunk->chunk_hdr) + 429 sizeof(sctp_chunkhdr_t)); 430 /* Replace the cause code with the "Unrecognized parameter" 431 * parameter type. 432 */ 433 sctp_addto_chunk(repl, len, unk_param); 434 sctp_chunk_free(err_chunk); 435 } 436 437 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 438 439 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 440 441 /* 442 * Note: After sending out INIT ACK with the State Cookie parameter, 443 * "Z" MUST NOT allocate any resources, nor keep any states for the 444 * new association. Otherwise, "Z" will be vulnerable to resource 445 * attacks. 446 */ 447 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 448 449 return SCTP_DISPOSITION_DELETE_TCB; 450 451 nomem_init: 452 sctp_association_free(new_asoc); 453 nomem: 454 if (err_chunk) 455 sctp_chunk_free(err_chunk); 456 return SCTP_DISPOSITION_NOMEM; 457 } 458 459 /* 460 * Respond to a normal INIT ACK chunk. 461 * We are the side that is initiating the association. 462 * 463 * Section: 5.1 Normal Establishment of an Association, C 464 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 465 * timer and leave COOKIE-WAIT state. "A" shall then send the State 466 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 467 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 468 * 469 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 470 * DATA chunks, but it MUST be the first chunk in the packet and 471 * until the COOKIE ACK is returned the sender MUST NOT send any 472 * other packets to the peer. 473 * 474 * Verification Tag: 3.3.3 475 * If the value of the Initiate Tag in a received INIT ACK chunk is 476 * found to be 0, the receiver MUST treat it as an error and close the 477 * association by transmitting an ABORT. 478 * 479 * Inputs 480 * (endpoint, asoc, chunk) 481 * 482 * Outputs 483 * (asoc, reply_msg, msg_up, timers, counters) 484 * 485 * The return value is the disposition of the chunk. 486 */ 487 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, 488 const struct sctp_association *asoc, 489 const sctp_subtype_t type, 490 void *arg, 491 sctp_cmd_seq_t *commands) 492 { 493 struct sctp_chunk *chunk = arg; 494 sctp_init_chunk_t *initchunk; 495 struct sctp_chunk *err_chunk; 496 struct sctp_packet *packet; 497 498 if (!sctp_vtag_verify(chunk, asoc)) 499 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 500 501 /* 6.10 Bundling 502 * An endpoint MUST NOT bundle INIT, INIT ACK or 503 * SHUTDOWN COMPLETE with any other chunks. 504 */ 505 if (!chunk->singleton) 506 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 507 508 /* Make sure that the INIT-ACK chunk has a valid length */ 509 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 510 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 511 commands); 512 /* Grab the INIT header. */ 513 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 514 515 /* Verify the INIT chunk before processing it. */ 516 err_chunk = NULL; 517 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 518 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 519 &err_chunk)) { 520 521 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 522 523 /* This chunk contains fatal error. It is to be discarded. 524 * Send an ABORT, with causes. If there are no causes, 525 * then there wasn't enough memory. Just terminate 526 * the association. 527 */ 528 if (err_chunk) { 529 packet = sctp_abort_pkt_new(ep, asoc, arg, 530 (__u8 *)(err_chunk->chunk_hdr) + 531 sizeof(sctp_chunkhdr_t), 532 ntohs(err_chunk->chunk_hdr->length) - 533 sizeof(sctp_chunkhdr_t)); 534 535 sctp_chunk_free(err_chunk); 536 537 if (packet) { 538 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 539 SCTP_PACKET(packet)); 540 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 541 error = SCTP_ERROR_INV_PARAM; 542 } 543 } 544 545 /* SCTP-AUTH, Section 6.3: 546 * It should be noted that if the receiver wants to tear 547 * down an association in an authenticated way only, the 548 * handling of malformed packets should not result in 549 * tearing down the association. 550 * 551 * This means that if we only want to abort associations 552 * in an authenticated way (i.e AUTH+ABORT), then we 553 * can't destroy this association just because the packet 554 * was malformed. 555 */ 556 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 557 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 558 559 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 560 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, 561 asoc, chunk->transport); 562 } 563 564 /* Tag the variable length parameters. Note that we never 565 * convert the parameters in an INIT chunk. 566 */ 567 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 568 569 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 570 571 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 572 SCTP_PEER_INIT(initchunk)); 573 574 /* Reset init error count upon receipt of INIT-ACK. */ 575 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 576 577 /* 5.1 C) "A" shall stop the T1-init timer and leave 578 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 579 * timer, and enter the COOKIE-ECHOED state. 580 */ 581 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 582 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 583 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 584 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 585 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 586 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 587 588 /* SCTP-AUTH: genereate the assocition shared keys so that 589 * we can potentially signe the COOKIE-ECHO. 590 */ 591 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 592 593 /* 5.1 C) "A" shall then send the State Cookie received in the 594 * INIT ACK chunk in a COOKIE ECHO chunk, ... 595 */ 596 /* If there is any errors to report, send the ERROR chunk generated 597 * for unknown parameters as well. 598 */ 599 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 600 SCTP_CHUNK(err_chunk)); 601 602 return SCTP_DISPOSITION_CONSUME; 603 } 604 605 /* 606 * Respond to a normal COOKIE ECHO chunk. 607 * We are the side that is being asked for an association. 608 * 609 * Section: 5.1 Normal Establishment of an Association, D 610 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 611 * with a COOKIE ACK chunk after building a TCB and moving to 612 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 613 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 614 * chunk MUST be the first chunk in the packet. 615 * 616 * IMPLEMENTATION NOTE: An implementation may choose to send the 617 * Communication Up notification to the SCTP user upon reception 618 * of a valid COOKIE ECHO chunk. 619 * 620 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 621 * D) Rules for packet carrying a COOKIE ECHO 622 * 623 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 624 * Initial Tag received in the INIT ACK. 625 * 626 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 627 * 628 * Inputs 629 * (endpoint, asoc, chunk) 630 * 631 * Outputs 632 * (asoc, reply_msg, msg_up, timers, counters) 633 * 634 * The return value is the disposition of the chunk. 635 */ 636 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, 637 const struct sctp_association *asoc, 638 const sctp_subtype_t type, void *arg, 639 sctp_cmd_seq_t *commands) 640 { 641 struct sctp_chunk *chunk = arg; 642 struct sctp_association *new_asoc; 643 sctp_init_chunk_t *peer_init; 644 struct sctp_chunk *repl; 645 struct sctp_ulpevent *ev, *ai_ev = NULL; 646 int error = 0; 647 struct sctp_chunk *err_chk_p; 648 struct sock *sk; 649 650 /* If the packet is an OOTB packet which is temporarily on the 651 * control endpoint, respond with an ABORT. 652 */ 653 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) { 654 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 655 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 656 } 657 658 /* Make sure that the COOKIE_ECHO chunk has a valid length. 659 * In this case, we check that we have enough for at least a 660 * chunk header. More detailed verification is done 661 * in sctp_unpack_cookie(). 662 */ 663 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 664 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 665 666 /* If the endpoint is not listening or if the number of associations 667 * on the TCP-style socket exceed the max backlog, respond with an 668 * ABORT. 669 */ 670 sk = ep->base.sk; 671 if (!sctp_sstate(sk, LISTENING) || 672 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 673 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 674 675 /* "Decode" the chunk. We have no optional parameters so we 676 * are in good shape. 677 */ 678 chunk->subh.cookie_hdr = 679 (struct sctp_signed_cookie *)chunk->skb->data; 680 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 681 sizeof(sctp_chunkhdr_t))) 682 goto nomem; 683 684 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 685 * "Z" will reply with a COOKIE ACK chunk after building a TCB 686 * and moving to the ESTABLISHED state. 687 */ 688 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 689 &err_chk_p); 690 691 /* FIXME: 692 * If the re-build failed, what is the proper error path 693 * from here? 694 * 695 * [We should abort the association. --piggy] 696 */ 697 if (!new_asoc) { 698 /* FIXME: Several errors are possible. A bad cookie should 699 * be silently discarded, but think about logging it too. 700 */ 701 switch (error) { 702 case -SCTP_IERROR_NOMEM: 703 goto nomem; 704 705 case -SCTP_IERROR_STALE_COOKIE: 706 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 707 err_chk_p); 708 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 709 710 case -SCTP_IERROR_BAD_SIG: 711 default: 712 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 713 } 714 } 715 716 717 /* Delay state machine commands until later. 718 * 719 * Re-build the bind address for the association is done in 720 * the sctp_unpack_cookie() already. 721 */ 722 /* This is a brand-new association, so these are not yet side 723 * effects--it is safe to run them here. 724 */ 725 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 726 727 if (!sctp_process_init(new_asoc, chunk, 728 &chunk->subh.cookie_hdr->c.peer_addr, 729 peer_init, GFP_ATOMIC)) 730 goto nomem_init; 731 732 /* SCTP-AUTH: Now that we've populate required fields in 733 * sctp_process_init, set up the assocaition shared keys as 734 * necessary so that we can potentially authenticate the ACK 735 */ 736 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 737 if (error) 738 goto nomem_init; 739 740 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 741 * is supposed to be authenticated and we have to do delayed 742 * authentication. We've just recreated the association using 743 * the information in the cookie and now it's much easier to 744 * do the authentication. 745 */ 746 if (chunk->auth_chunk) { 747 struct sctp_chunk auth; 748 sctp_ierror_t ret; 749 750 /* set-up our fake chunk so that we can process it */ 751 auth.skb = chunk->auth_chunk; 752 auth.asoc = chunk->asoc; 753 auth.sctp_hdr = chunk->sctp_hdr; 754 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 755 sizeof(sctp_chunkhdr_t)); 756 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 757 auth.transport = chunk->transport; 758 759 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth); 760 761 /* We can now safely free the auth_chunk clone */ 762 kfree_skb(chunk->auth_chunk); 763 764 if (ret != SCTP_IERROR_NO_ERROR) { 765 sctp_association_free(new_asoc); 766 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 767 } 768 } 769 770 repl = sctp_make_cookie_ack(new_asoc, chunk); 771 if (!repl) 772 goto nomem_init; 773 774 /* RFC 2960 5.1 Normal Establishment of an Association 775 * 776 * D) IMPLEMENTATION NOTE: An implementation may choose to 777 * send the Communication Up notification to the SCTP user 778 * upon reception of a valid COOKIE ECHO chunk. 779 */ 780 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 781 new_asoc->c.sinit_num_ostreams, 782 new_asoc->c.sinit_max_instreams, 783 NULL, GFP_ATOMIC); 784 if (!ev) 785 goto nomem_ev; 786 787 /* Sockets API Draft Section 5.3.1.6 788 * When a peer sends a Adaptation Layer Indication parameter , SCTP 789 * delivers this notification to inform the application that of the 790 * peers requested adaptation layer. 791 */ 792 if (new_asoc->peer.adaptation_ind) { 793 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 794 GFP_ATOMIC); 795 if (!ai_ev) 796 goto nomem_aiev; 797 } 798 799 /* Add all the state machine commands now since we've created 800 * everything. This way we don't introduce memory corruptions 801 * during side-effect processing and correclty count established 802 * associations. 803 */ 804 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 805 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 806 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 807 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 808 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 809 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 810 811 if (new_asoc->autoclose) 812 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 813 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 814 815 /* This will send the COOKIE ACK */ 816 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 817 818 /* Queue the ASSOC_CHANGE event */ 819 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 820 821 /* Send up the Adaptation Layer Indication event */ 822 if (ai_ev) 823 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 824 SCTP_ULPEVENT(ai_ev)); 825 826 return SCTP_DISPOSITION_CONSUME; 827 828 nomem_aiev: 829 sctp_ulpevent_free(ev); 830 nomem_ev: 831 sctp_chunk_free(repl); 832 nomem_init: 833 sctp_association_free(new_asoc); 834 nomem: 835 return SCTP_DISPOSITION_NOMEM; 836 } 837 838 /* 839 * Respond to a normal COOKIE ACK chunk. 840 * We are the side that is being asked for an association. 841 * 842 * RFC 2960 5.1 Normal Establishment of an Association 843 * 844 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 845 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 846 * timer. It may also notify its ULP about the successful 847 * establishment of the association with a Communication Up 848 * notification (see Section 10). 849 * 850 * Verification Tag: 851 * Inputs 852 * (endpoint, asoc, chunk) 853 * 854 * Outputs 855 * (asoc, reply_msg, msg_up, timers, counters) 856 * 857 * The return value is the disposition of the chunk. 858 */ 859 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, 860 const struct sctp_association *asoc, 861 const sctp_subtype_t type, void *arg, 862 sctp_cmd_seq_t *commands) 863 { 864 struct sctp_chunk *chunk = arg; 865 struct sctp_ulpevent *ev; 866 867 if (!sctp_vtag_verify(chunk, asoc)) 868 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 869 870 /* Verify that the chunk length for the COOKIE-ACK is OK. 871 * If we don't do this, any bundled chunks may be junked. 872 */ 873 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 874 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 875 commands); 876 877 /* Reset init error count upon receipt of COOKIE-ACK, 878 * to avoid problems with the managemement of this 879 * counter in stale cookie situations when a transition back 880 * from the COOKIE-ECHOED state to the COOKIE-WAIT 881 * state is performed. 882 */ 883 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 884 885 /* RFC 2960 5.1 Normal Establishment of an Association 886 * 887 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 888 * from the COOKIE-ECHOED state to the ESTABLISHED state, 889 * stopping the T1-cookie timer. 890 */ 891 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 892 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 893 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 894 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 895 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 896 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); 897 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 898 if (asoc->autoclose) 899 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 900 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 901 902 /* It may also notify its ULP about the successful 903 * establishment of the association with a Communication Up 904 * notification (see Section 10). 905 */ 906 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 907 0, asoc->c.sinit_num_ostreams, 908 asoc->c.sinit_max_instreams, 909 NULL, GFP_ATOMIC); 910 911 if (!ev) 912 goto nomem; 913 914 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 915 916 /* Sockets API Draft Section 5.3.1.6 917 * When a peer sends a Adaptation Layer Indication parameter , SCTP 918 * delivers this notification to inform the application that of the 919 * peers requested adaptation layer. 920 */ 921 if (asoc->peer.adaptation_ind) { 922 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 923 if (!ev) 924 goto nomem; 925 926 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 927 SCTP_ULPEVENT(ev)); 928 } 929 930 return SCTP_DISPOSITION_CONSUME; 931 nomem: 932 return SCTP_DISPOSITION_NOMEM; 933 } 934 935 /* Generate and sendout a heartbeat packet. */ 936 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 937 const struct sctp_association *asoc, 938 const sctp_subtype_t type, 939 void *arg, 940 sctp_cmd_seq_t *commands) 941 { 942 struct sctp_transport *transport = (struct sctp_transport *) arg; 943 struct sctp_chunk *reply; 944 945 /* Send a heartbeat to our peer. */ 946 reply = sctp_make_heartbeat(asoc, transport); 947 if (!reply) 948 return SCTP_DISPOSITION_NOMEM; 949 950 /* Set rto_pending indicating that an RTT measurement 951 * is started with this heartbeat chunk. 952 */ 953 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 954 SCTP_TRANSPORT(transport)); 955 956 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 957 return SCTP_DISPOSITION_CONSUME; 958 } 959 960 /* Generate a HEARTBEAT packet on the given transport. */ 961 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 962 const struct sctp_association *asoc, 963 const sctp_subtype_t type, 964 void *arg, 965 sctp_cmd_seq_t *commands) 966 { 967 struct sctp_transport *transport = (struct sctp_transport *) arg; 968 969 if (asoc->overall_error_count >= asoc->max_retrans) { 970 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 971 SCTP_ERROR(ETIMEDOUT)); 972 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 973 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 974 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 975 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 976 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 977 return SCTP_DISPOSITION_DELETE_TCB; 978 } 979 980 /* Section 3.3.5. 981 * The Sender-specific Heartbeat Info field should normally include 982 * information about the sender's current time when this HEARTBEAT 983 * chunk is sent and the destination transport address to which this 984 * HEARTBEAT is sent (see Section 8.3). 985 */ 986 987 if (transport->param_flags & SPP_HB_ENABLE) { 988 if (SCTP_DISPOSITION_NOMEM == 989 sctp_sf_heartbeat(ep, asoc, type, arg, 990 commands)) 991 return SCTP_DISPOSITION_NOMEM; 992 993 /* Set transport error counter and association error counter 994 * when sending heartbeat. 995 */ 996 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 997 SCTP_TRANSPORT(transport)); 998 } 999 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1000 SCTP_TRANSPORT(transport)); 1001 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1002 SCTP_TRANSPORT(transport)); 1003 1004 return SCTP_DISPOSITION_CONSUME; 1005 } 1006 1007 /* 1008 * Process an heartbeat request. 1009 * 1010 * Section: 8.3 Path Heartbeat 1011 * The receiver of the HEARTBEAT should immediately respond with a 1012 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1013 * from the received HEARTBEAT chunk. 1014 * 1015 * Verification Tag: 8.5 Verification Tag [Normal verification] 1016 * When receiving an SCTP packet, the endpoint MUST ensure that the 1017 * value in the Verification Tag field of the received SCTP packet 1018 * matches its own Tag. If the received Verification Tag value does not 1019 * match the receiver's own tag value, the receiver shall silently 1020 * discard the packet and shall not process it any further except for 1021 * those cases listed in Section 8.5.1 below. 1022 * 1023 * Inputs 1024 * (endpoint, asoc, chunk) 1025 * 1026 * Outputs 1027 * (asoc, reply_msg, msg_up, timers, counters) 1028 * 1029 * The return value is the disposition of the chunk. 1030 */ 1031 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 1032 const struct sctp_association *asoc, 1033 const sctp_subtype_t type, 1034 void *arg, 1035 sctp_cmd_seq_t *commands) 1036 { 1037 struct sctp_chunk *chunk = arg; 1038 struct sctp_chunk *reply; 1039 size_t paylen = 0; 1040 1041 if (!sctp_vtag_verify(chunk, asoc)) 1042 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1043 1044 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1045 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1046 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1047 commands); 1048 1049 /* 8.3 The receiver of the HEARTBEAT should immediately 1050 * respond with a HEARTBEAT ACK that contains the Heartbeat 1051 * Information field copied from the received HEARTBEAT chunk. 1052 */ 1053 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1054 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1055 if (!pskb_pull(chunk->skb, paylen)) 1056 goto nomem; 1057 1058 reply = sctp_make_heartbeat_ack(asoc, chunk, 1059 chunk->subh.hb_hdr, paylen); 1060 if (!reply) 1061 goto nomem; 1062 1063 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1064 return SCTP_DISPOSITION_CONSUME; 1065 1066 nomem: 1067 return SCTP_DISPOSITION_NOMEM; 1068 } 1069 1070 /* 1071 * Process the returning HEARTBEAT ACK. 1072 * 1073 * Section: 8.3 Path Heartbeat 1074 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1075 * should clear the error counter of the destination transport 1076 * address to which the HEARTBEAT was sent, and mark the destination 1077 * transport address as active if it is not so marked. The endpoint may 1078 * optionally report to the upper layer when an inactive destination 1079 * address is marked as active due to the reception of the latest 1080 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1081 * clear the association overall error count as well (as defined 1082 * in section 8.1). 1083 * 1084 * The receiver of the HEARTBEAT ACK should also perform an RTT 1085 * measurement for that destination transport address using the time 1086 * value carried in the HEARTBEAT ACK chunk. 1087 * 1088 * Verification Tag: 8.5 Verification Tag [Normal verification] 1089 * 1090 * Inputs 1091 * (endpoint, asoc, chunk) 1092 * 1093 * Outputs 1094 * (asoc, reply_msg, msg_up, timers, counters) 1095 * 1096 * The return value is the disposition of the chunk. 1097 */ 1098 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 1099 const struct sctp_association *asoc, 1100 const sctp_subtype_t type, 1101 void *arg, 1102 sctp_cmd_seq_t *commands) 1103 { 1104 struct sctp_chunk *chunk = arg; 1105 union sctp_addr from_addr; 1106 struct sctp_transport *link; 1107 sctp_sender_hb_info_t *hbinfo; 1108 unsigned long max_interval; 1109 1110 if (!sctp_vtag_verify(chunk, asoc)) 1111 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1112 1113 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1114 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1115 sizeof(sctp_sender_hb_info_t))) 1116 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1117 commands); 1118 1119 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1120 /* Make sure that the length of the parameter is what we expect */ 1121 if (ntohs(hbinfo->param_hdr.length) != 1122 sizeof(sctp_sender_hb_info_t)) { 1123 return SCTP_DISPOSITION_DISCARD; 1124 } 1125 1126 from_addr = hbinfo->daddr; 1127 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1128 1129 /* This should never happen, but lets log it if so. */ 1130 if (unlikely(!link)) { 1131 if (from_addr.sa.sa_family == AF_INET6) { 1132 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1133 __func__, 1134 asoc, 1135 &from_addr.v6.sin6_addr); 1136 } else { 1137 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1138 __func__, 1139 asoc, 1140 &from_addr.v4.sin_addr.s_addr); 1141 } 1142 return SCTP_DISPOSITION_DISCARD; 1143 } 1144 1145 /* Validate the 64-bit random nonce. */ 1146 if (hbinfo->hb_nonce != link->hb_nonce) 1147 return SCTP_DISPOSITION_DISCARD; 1148 1149 max_interval = link->hbinterval + link->rto; 1150 1151 /* Check if the timestamp looks valid. */ 1152 if (time_after(hbinfo->sent_at, jiffies) || 1153 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1154 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp " 1155 "received for transport: %p\n", 1156 __func__, link); 1157 return SCTP_DISPOSITION_DISCARD; 1158 } 1159 1160 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1161 * the HEARTBEAT should clear the error counter of the 1162 * destination transport address to which the HEARTBEAT was 1163 * sent and mark the destination transport address as active if 1164 * it is not so marked. 1165 */ 1166 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1167 1168 return SCTP_DISPOSITION_CONSUME; 1169 } 1170 1171 /* Helper function to send out an abort for the restart 1172 * condition. 1173 */ 1174 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1175 struct sctp_chunk *init, 1176 sctp_cmd_seq_t *commands) 1177 { 1178 int len; 1179 struct sctp_packet *pkt; 1180 union sctp_addr_param *addrparm; 1181 struct sctp_errhdr *errhdr; 1182 struct sctp_endpoint *ep; 1183 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1184 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1185 1186 /* Build the error on the stack. We are way to malloc crazy 1187 * throughout the code today. 1188 */ 1189 errhdr = (struct sctp_errhdr *)buffer; 1190 addrparm = (union sctp_addr_param *)errhdr->variable; 1191 1192 /* Copy into a parm format. */ 1193 len = af->to_addr_param(ssa, addrparm); 1194 len += sizeof(sctp_errhdr_t); 1195 1196 errhdr->cause = SCTP_ERROR_RESTART; 1197 errhdr->length = htons(len); 1198 1199 /* Assign to the control socket. */ 1200 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1201 1202 /* Association is NULL since this may be a restart attack and we 1203 * want to send back the attacker's vtag. 1204 */ 1205 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1206 1207 if (!pkt) 1208 goto out; 1209 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1210 1211 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1212 1213 /* Discard the rest of the inbound packet. */ 1214 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1215 1216 out: 1217 /* Even if there is no memory, treat as a failure so 1218 * the packet will get dropped. 1219 */ 1220 return 0; 1221 } 1222 1223 static bool list_has_sctp_addr(const struct list_head *list, 1224 union sctp_addr *ipaddr) 1225 { 1226 struct sctp_transport *addr; 1227 1228 list_for_each_entry(addr, list, transports) { 1229 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1230 return true; 1231 } 1232 1233 return false; 1234 } 1235 /* A restart is occurring, check to make sure no new addresses 1236 * are being added as we may be under a takeover attack. 1237 */ 1238 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1239 const struct sctp_association *asoc, 1240 struct sctp_chunk *init, 1241 sctp_cmd_seq_t *commands) 1242 { 1243 struct sctp_transport *new_addr; 1244 int ret = 1; 1245 1246 /* Implementor's Guide - Section 5.2.2 1247 * ... 1248 * Before responding the endpoint MUST check to see if the 1249 * unexpected INIT adds new addresses to the association. If new 1250 * addresses are added to the association, the endpoint MUST respond 1251 * with an ABORT.. 1252 */ 1253 1254 /* Search through all current addresses and make sure 1255 * we aren't adding any new ones. 1256 */ 1257 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1258 transports) { 1259 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1260 &new_addr->ipaddr)) { 1261 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, 1262 commands); 1263 ret = 0; 1264 break; 1265 } 1266 } 1267 1268 /* Return success if all addresses were found. */ 1269 return ret; 1270 } 1271 1272 /* Populate the verification/tie tags based on overlapping INIT 1273 * scenario. 1274 * 1275 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1276 */ 1277 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1278 const struct sctp_association *asoc) 1279 { 1280 switch (asoc->state) { 1281 1282 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1283 1284 case SCTP_STATE_COOKIE_WAIT: 1285 new_asoc->c.my_vtag = asoc->c.my_vtag; 1286 new_asoc->c.my_ttag = asoc->c.my_vtag; 1287 new_asoc->c.peer_ttag = 0; 1288 break; 1289 1290 case SCTP_STATE_COOKIE_ECHOED: 1291 new_asoc->c.my_vtag = asoc->c.my_vtag; 1292 new_asoc->c.my_ttag = asoc->c.my_vtag; 1293 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1294 break; 1295 1296 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1297 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1298 */ 1299 default: 1300 new_asoc->c.my_ttag = asoc->c.my_vtag; 1301 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1302 break; 1303 } 1304 1305 /* Other parameters for the endpoint SHOULD be copied from the 1306 * existing parameters of the association (e.g. number of 1307 * outbound streams) into the INIT ACK and cookie. 1308 */ 1309 new_asoc->rwnd = asoc->rwnd; 1310 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1311 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1312 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1313 } 1314 1315 /* 1316 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1317 * handling action. 1318 * 1319 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1320 * 1321 * Returns value representing action to be taken. These action values 1322 * correspond to Action/Description values in RFC 2960, Table 2. 1323 */ 1324 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1325 const struct sctp_association *asoc) 1326 { 1327 /* In this case, the peer may have restarted. */ 1328 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1329 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1330 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1331 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1332 return 'A'; 1333 1334 /* Collision case B. */ 1335 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1336 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1337 (0 == asoc->c.peer_vtag))) { 1338 return 'B'; 1339 } 1340 1341 /* Collision case D. */ 1342 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1343 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1344 return 'D'; 1345 1346 /* Collision case C. */ 1347 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1348 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1349 (0 == new_asoc->c.my_ttag) && 1350 (0 == new_asoc->c.peer_ttag)) 1351 return 'C'; 1352 1353 /* No match to any of the special cases; discard this packet. */ 1354 return 'E'; 1355 } 1356 1357 /* Common helper routine for both duplicate and simulataneous INIT 1358 * chunk handling. 1359 */ 1360 static sctp_disposition_t sctp_sf_do_unexpected_init( 1361 const struct sctp_endpoint *ep, 1362 const struct sctp_association *asoc, 1363 const sctp_subtype_t type, 1364 void *arg, sctp_cmd_seq_t *commands) 1365 { 1366 sctp_disposition_t retval; 1367 struct sctp_chunk *chunk = arg; 1368 struct sctp_chunk *repl; 1369 struct sctp_association *new_asoc; 1370 struct sctp_chunk *err_chunk; 1371 struct sctp_packet *packet; 1372 sctp_unrecognized_param_t *unk_param; 1373 int len; 1374 1375 /* 6.10 Bundling 1376 * An endpoint MUST NOT bundle INIT, INIT ACK or 1377 * SHUTDOWN COMPLETE with any other chunks. 1378 * 1379 * IG Section 2.11.2 1380 * Furthermore, we require that the receiver of an INIT chunk MUST 1381 * enforce these rules by silently discarding an arriving packet 1382 * with an INIT chunk that is bundled with other chunks. 1383 */ 1384 if (!chunk->singleton) 1385 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1386 1387 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1388 * Tag. 1389 */ 1390 if (chunk->sctp_hdr->vtag != 0) 1391 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1392 1393 /* Make sure that the INIT chunk has a valid length. 1394 * In this case, we generate a protocol violation since we have 1395 * an association established. 1396 */ 1397 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1398 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1399 commands); 1400 /* Grab the INIT header. */ 1401 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1402 1403 /* Tag the variable length parameters. */ 1404 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1405 1406 /* Verify the INIT chunk before processing it. */ 1407 err_chunk = NULL; 1408 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1409 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1410 &err_chunk)) { 1411 /* This chunk contains fatal error. It is to be discarded. 1412 * Send an ABORT, with causes if there is any. 1413 */ 1414 if (err_chunk) { 1415 packet = sctp_abort_pkt_new(ep, asoc, arg, 1416 (__u8 *)(err_chunk->chunk_hdr) + 1417 sizeof(sctp_chunkhdr_t), 1418 ntohs(err_chunk->chunk_hdr->length) - 1419 sizeof(sctp_chunkhdr_t)); 1420 1421 if (packet) { 1422 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1423 SCTP_PACKET(packet)); 1424 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1425 retval = SCTP_DISPOSITION_CONSUME; 1426 } else { 1427 retval = SCTP_DISPOSITION_NOMEM; 1428 } 1429 goto cleanup; 1430 } else { 1431 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1432 commands); 1433 } 1434 } 1435 1436 /* 1437 * Other parameters for the endpoint SHOULD be copied from the 1438 * existing parameters of the association (e.g. number of 1439 * outbound streams) into the INIT ACK and cookie. 1440 * FIXME: We are copying parameters from the endpoint not the 1441 * association. 1442 */ 1443 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1444 if (!new_asoc) 1445 goto nomem; 1446 1447 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1448 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1449 goto nomem; 1450 1451 /* In the outbound INIT ACK the endpoint MUST copy its current 1452 * Verification Tag and Peers Verification tag into a reserved 1453 * place (local tie-tag and per tie-tag) within the state cookie. 1454 */ 1455 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1456 (sctp_init_chunk_t *)chunk->chunk_hdr, 1457 GFP_ATOMIC)) 1458 goto nomem; 1459 1460 /* Make sure no new addresses are being added during the 1461 * restart. Do not do this check for COOKIE-WAIT state, 1462 * since there are no peer addresses to check against. 1463 * Upon return an ABORT will have been sent if needed. 1464 */ 1465 if (!sctp_state(asoc, COOKIE_WAIT)) { 1466 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1467 commands)) { 1468 retval = SCTP_DISPOSITION_CONSUME; 1469 goto nomem_retval; 1470 } 1471 } 1472 1473 sctp_tietags_populate(new_asoc, asoc); 1474 1475 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1476 1477 /* If there are errors need to be reported for unknown parameters, 1478 * make sure to reserve enough room in the INIT ACK for them. 1479 */ 1480 len = 0; 1481 if (err_chunk) { 1482 len = ntohs(err_chunk->chunk_hdr->length) - 1483 sizeof(sctp_chunkhdr_t); 1484 } 1485 1486 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1487 if (!repl) 1488 goto nomem; 1489 1490 /* If there are errors need to be reported for unknown parameters, 1491 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1492 * parameter. 1493 */ 1494 if (err_chunk) { 1495 /* Get the "Unrecognized parameter" parameter(s) out of the 1496 * ERROR chunk generated by sctp_verify_init(). Since the 1497 * error cause code for "unknown parameter" and the 1498 * "Unrecognized parameter" type is the same, we can 1499 * construct the parameters in INIT ACK by copying the 1500 * ERROR causes over. 1501 */ 1502 unk_param = (sctp_unrecognized_param_t *) 1503 ((__u8 *)(err_chunk->chunk_hdr) + 1504 sizeof(sctp_chunkhdr_t)); 1505 /* Replace the cause code with the "Unrecognized parameter" 1506 * parameter type. 1507 */ 1508 sctp_addto_chunk(repl, len, unk_param); 1509 } 1510 1511 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1512 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1513 1514 /* 1515 * Note: After sending out INIT ACK with the State Cookie parameter, 1516 * "Z" MUST NOT allocate any resources for this new association. 1517 * Otherwise, "Z" will be vulnerable to resource attacks. 1518 */ 1519 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1520 retval = SCTP_DISPOSITION_CONSUME; 1521 1522 return retval; 1523 1524 nomem: 1525 retval = SCTP_DISPOSITION_NOMEM; 1526 nomem_retval: 1527 if (new_asoc) 1528 sctp_association_free(new_asoc); 1529 cleanup: 1530 if (err_chunk) 1531 sctp_chunk_free(err_chunk); 1532 return retval; 1533 } 1534 1535 /* 1536 * Handle simultaneous INIT. 1537 * This means we started an INIT and then we got an INIT request from 1538 * our peer. 1539 * 1540 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1541 * This usually indicates an initialization collision, i.e., each 1542 * endpoint is attempting, at about the same time, to establish an 1543 * association with the other endpoint. 1544 * 1545 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1546 * endpoint MUST respond with an INIT ACK using the same parameters it 1547 * sent in its original INIT chunk (including its Verification Tag, 1548 * unchanged). These original parameters are combined with those from the 1549 * newly received INIT chunk. The endpoint shall also generate a State 1550 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1551 * INIT to calculate the State Cookie. 1552 * 1553 * After that, the endpoint MUST NOT change its state, the T1-init 1554 * timer shall be left running and the corresponding TCB MUST NOT be 1555 * destroyed. The normal procedures for handling State Cookies when 1556 * a TCB exists will resolve the duplicate INITs to a single association. 1557 * 1558 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1559 * its Tie-Tags with the Tag information of itself and its peer (see 1560 * section 5.2.2 for a description of the Tie-Tags). 1561 * 1562 * Verification Tag: Not explicit, but an INIT can not have a valid 1563 * verification tag, so we skip the check. 1564 * 1565 * Inputs 1566 * (endpoint, asoc, chunk) 1567 * 1568 * Outputs 1569 * (asoc, reply_msg, msg_up, timers, counters) 1570 * 1571 * The return value is the disposition of the chunk. 1572 */ 1573 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1574 const struct sctp_association *asoc, 1575 const sctp_subtype_t type, 1576 void *arg, 1577 sctp_cmd_seq_t *commands) 1578 { 1579 /* Call helper to do the real work for both simulataneous and 1580 * duplicate INIT chunk handling. 1581 */ 1582 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1583 } 1584 1585 /* 1586 * Handle duplicated INIT messages. These are usually delayed 1587 * restransmissions. 1588 * 1589 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1590 * COOKIE-ECHOED and COOKIE-WAIT 1591 * 1592 * Unless otherwise stated, upon reception of an unexpected INIT for 1593 * this association, the endpoint shall generate an INIT ACK with a 1594 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1595 * current Verification Tag and peer's Verification Tag into a reserved 1596 * place within the state cookie. We shall refer to these locations as 1597 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1598 * containing this INIT ACK MUST carry a Verification Tag value equal to 1599 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1600 * MUST contain a new Initiation Tag (randomly generated see Section 1601 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1602 * existing parameters of the association (e.g. number of outbound 1603 * streams) into the INIT ACK and cookie. 1604 * 1605 * After sending out the INIT ACK, the endpoint shall take no further 1606 * actions, i.e., the existing association, including its current state, 1607 * and the corresponding TCB MUST NOT be changed. 1608 * 1609 * Note: Only when a TCB exists and the association is not in a COOKIE- 1610 * WAIT state are the Tie-Tags populated. For a normal association INIT 1611 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1612 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1613 * State Cookie are populated as specified in section 5.2.1. 1614 * 1615 * Verification Tag: Not specified, but an INIT has no way of knowing 1616 * what the verification tag could be, so we ignore it. 1617 * 1618 * Inputs 1619 * (endpoint, asoc, chunk) 1620 * 1621 * Outputs 1622 * (asoc, reply_msg, msg_up, timers, counters) 1623 * 1624 * The return value is the disposition of the chunk. 1625 */ 1626 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1627 const struct sctp_association *asoc, 1628 const sctp_subtype_t type, 1629 void *arg, 1630 sctp_cmd_seq_t *commands) 1631 { 1632 /* Call helper to do the real work for both simulataneous and 1633 * duplicate INIT chunk handling. 1634 */ 1635 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1636 } 1637 1638 1639 /* 1640 * Unexpected INIT-ACK handler. 1641 * 1642 * Section 5.2.3 1643 * If an INIT ACK received by an endpoint in any state other than the 1644 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1645 * An unexpected INIT ACK usually indicates the processing of an old or 1646 * duplicated INIT chunk. 1647 */ 1648 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep, 1649 const struct sctp_association *asoc, 1650 const sctp_subtype_t type, 1651 void *arg, sctp_cmd_seq_t *commands) 1652 { 1653 /* Per the above section, we'll discard the chunk if we have an 1654 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1655 */ 1656 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 1657 return sctp_sf_ootb(ep, asoc, type, arg, commands); 1658 else 1659 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 1660 } 1661 1662 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1663 * 1664 * Section 5.2.4 1665 * A) In this case, the peer may have restarted. 1666 */ 1667 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1668 const struct sctp_association *asoc, 1669 struct sctp_chunk *chunk, 1670 sctp_cmd_seq_t *commands, 1671 struct sctp_association *new_asoc) 1672 { 1673 sctp_init_chunk_t *peer_init; 1674 struct sctp_ulpevent *ev; 1675 struct sctp_chunk *repl; 1676 struct sctp_chunk *err; 1677 sctp_disposition_t disposition; 1678 1679 /* new_asoc is a brand-new association, so these are not yet 1680 * side effects--it is safe to run them here. 1681 */ 1682 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1683 1684 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1685 GFP_ATOMIC)) 1686 goto nomem; 1687 1688 /* Make sure no new addresses are being added during the 1689 * restart. Though this is a pretty complicated attack 1690 * since you'd have to get inside the cookie. 1691 */ 1692 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1693 return SCTP_DISPOSITION_CONSUME; 1694 } 1695 1696 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1697 * the peer has restarted (Action A), it MUST NOT setup a new 1698 * association but instead resend the SHUTDOWN ACK and send an ERROR 1699 * chunk with a "Cookie Received while Shutting Down" error cause to 1700 * its peer. 1701 */ 1702 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1703 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1704 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1705 chunk, commands); 1706 if (SCTP_DISPOSITION_NOMEM == disposition) 1707 goto nomem; 1708 1709 err = sctp_make_op_error(asoc, chunk, 1710 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1711 NULL, 0, 0); 1712 if (err) 1713 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1714 SCTP_CHUNK(err)); 1715 1716 return SCTP_DISPOSITION_CONSUME; 1717 } 1718 1719 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1720 * data. Consider the optional choice of resending of this data. 1721 */ 1722 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1723 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1724 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1725 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1726 1727 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1728 * and ASCONF-ACK cache. 1729 */ 1730 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1731 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1732 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1733 1734 repl = sctp_make_cookie_ack(new_asoc, chunk); 1735 if (!repl) 1736 goto nomem; 1737 1738 /* Report association restart to upper layer. */ 1739 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1740 new_asoc->c.sinit_num_ostreams, 1741 new_asoc->c.sinit_max_instreams, 1742 NULL, GFP_ATOMIC); 1743 if (!ev) 1744 goto nomem_ev; 1745 1746 /* Update the content of current association. */ 1747 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1748 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1749 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1750 return SCTP_DISPOSITION_CONSUME; 1751 1752 nomem_ev: 1753 sctp_chunk_free(repl); 1754 nomem: 1755 return SCTP_DISPOSITION_NOMEM; 1756 } 1757 1758 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1759 * 1760 * Section 5.2.4 1761 * B) In this case, both sides may be attempting to start an association 1762 * at about the same time but the peer endpoint started its INIT 1763 * after responding to the local endpoint's INIT 1764 */ 1765 /* This case represents an initialization collision. */ 1766 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1767 const struct sctp_association *asoc, 1768 struct sctp_chunk *chunk, 1769 sctp_cmd_seq_t *commands, 1770 struct sctp_association *new_asoc) 1771 { 1772 sctp_init_chunk_t *peer_init; 1773 struct sctp_chunk *repl; 1774 1775 /* new_asoc is a brand-new association, so these are not yet 1776 * side effects--it is safe to run them here. 1777 */ 1778 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1779 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1780 GFP_ATOMIC)) 1781 goto nomem; 1782 1783 /* Update the content of current association. */ 1784 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1785 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1786 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1787 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1788 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1789 1790 repl = sctp_make_cookie_ack(new_asoc, chunk); 1791 if (!repl) 1792 goto nomem; 1793 1794 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1795 1796 /* RFC 2960 5.1 Normal Establishment of an Association 1797 * 1798 * D) IMPLEMENTATION NOTE: An implementation may choose to 1799 * send the Communication Up notification to the SCTP user 1800 * upon reception of a valid COOKIE ECHO chunk. 1801 * 1802 * Sadly, this needs to be implemented as a side-effect, because 1803 * we are not guaranteed to have set the association id of the real 1804 * association and so these notifications need to be delayed until 1805 * the association id is allocated. 1806 */ 1807 1808 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1809 1810 /* Sockets API Draft Section 5.3.1.6 1811 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1812 * delivers this notification to inform the application that of the 1813 * peers requested adaptation layer. 1814 * 1815 * This also needs to be done as a side effect for the same reason as 1816 * above. 1817 */ 1818 if (asoc->peer.adaptation_ind) 1819 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1820 1821 return SCTP_DISPOSITION_CONSUME; 1822 1823 nomem: 1824 return SCTP_DISPOSITION_NOMEM; 1825 } 1826 1827 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1828 * 1829 * Section 5.2.4 1830 * C) In this case, the local endpoint's cookie has arrived late. 1831 * Before it arrived, the local endpoint sent an INIT and received an 1832 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1833 * but a new tag of its own. 1834 */ 1835 /* This case represents an initialization collision. */ 1836 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1837 const struct sctp_association *asoc, 1838 struct sctp_chunk *chunk, 1839 sctp_cmd_seq_t *commands, 1840 struct sctp_association *new_asoc) 1841 { 1842 /* The cookie should be silently discarded. 1843 * The endpoint SHOULD NOT change states and should leave 1844 * any timers running. 1845 */ 1846 return SCTP_DISPOSITION_DISCARD; 1847 } 1848 1849 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1850 * 1851 * Section 5.2.4 1852 * 1853 * D) When both local and remote tags match the endpoint should always 1854 * enter the ESTABLISHED state, if it has not already done so. 1855 */ 1856 /* This case represents an initialization collision. */ 1857 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1858 const struct sctp_association *asoc, 1859 struct sctp_chunk *chunk, 1860 sctp_cmd_seq_t *commands, 1861 struct sctp_association *new_asoc) 1862 { 1863 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1864 struct sctp_chunk *repl; 1865 1866 /* Clarification from Implementor's Guide: 1867 * D) When both local and remote tags match the endpoint should 1868 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1869 * It should stop any cookie timer that may be running and send 1870 * a COOKIE ACK. 1871 */ 1872 1873 /* Don't accidentally move back into established state. */ 1874 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1875 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1876 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1877 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1878 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1879 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1880 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1881 SCTP_NULL()); 1882 1883 /* RFC 2960 5.1 Normal Establishment of an Association 1884 * 1885 * D) IMPLEMENTATION NOTE: An implementation may choose 1886 * to send the Communication Up notification to the 1887 * SCTP user upon reception of a valid COOKIE 1888 * ECHO chunk. 1889 */ 1890 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1891 SCTP_COMM_UP, 0, 1892 asoc->c.sinit_num_ostreams, 1893 asoc->c.sinit_max_instreams, 1894 NULL, GFP_ATOMIC); 1895 if (!ev) 1896 goto nomem; 1897 1898 /* Sockets API Draft Section 5.3.1.6 1899 * When a peer sends a Adaptation Layer Indication parameter, 1900 * SCTP delivers this notification to inform the application 1901 * that of the peers requested adaptation layer. 1902 */ 1903 if (asoc->peer.adaptation_ind) { 1904 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1905 GFP_ATOMIC); 1906 if (!ai_ev) 1907 goto nomem; 1908 1909 } 1910 } 1911 1912 repl = sctp_make_cookie_ack(new_asoc, chunk); 1913 if (!repl) 1914 goto nomem; 1915 1916 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1917 1918 if (ev) 1919 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1920 SCTP_ULPEVENT(ev)); 1921 if (ai_ev) 1922 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1923 SCTP_ULPEVENT(ai_ev)); 1924 1925 return SCTP_DISPOSITION_CONSUME; 1926 1927 nomem: 1928 if (ai_ev) 1929 sctp_ulpevent_free(ai_ev); 1930 if (ev) 1931 sctp_ulpevent_free(ev); 1932 return SCTP_DISPOSITION_NOMEM; 1933 } 1934 1935 /* 1936 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1937 * chunk was retransmitted and then delayed in the network. 1938 * 1939 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1940 * 1941 * Verification Tag: None. Do cookie validation. 1942 * 1943 * Inputs 1944 * (endpoint, asoc, chunk) 1945 * 1946 * Outputs 1947 * (asoc, reply_msg, msg_up, timers, counters) 1948 * 1949 * The return value is the disposition of the chunk. 1950 */ 1951 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1952 const struct sctp_association *asoc, 1953 const sctp_subtype_t type, 1954 void *arg, 1955 sctp_cmd_seq_t *commands) 1956 { 1957 sctp_disposition_t retval; 1958 struct sctp_chunk *chunk = arg; 1959 struct sctp_association *new_asoc; 1960 int error = 0; 1961 char action; 1962 struct sctp_chunk *err_chk_p; 1963 1964 /* Make sure that the chunk has a valid length from the protocol 1965 * perspective. In this case check to make sure we have at least 1966 * enough for the chunk header. Cookie length verification is 1967 * done later. 1968 */ 1969 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1970 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1971 commands); 1972 1973 /* "Decode" the chunk. We have no optional parameters so we 1974 * are in good shape. 1975 */ 1976 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1977 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1978 sizeof(sctp_chunkhdr_t))) 1979 goto nomem; 1980 1981 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1982 * of a duplicate COOKIE ECHO match the Verification Tags of the 1983 * current association, consider the State Cookie valid even if 1984 * the lifespan is exceeded. 1985 */ 1986 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1987 &err_chk_p); 1988 1989 /* FIXME: 1990 * If the re-build failed, what is the proper error path 1991 * from here? 1992 * 1993 * [We should abort the association. --piggy] 1994 */ 1995 if (!new_asoc) { 1996 /* FIXME: Several errors are possible. A bad cookie should 1997 * be silently discarded, but think about logging it too. 1998 */ 1999 switch (error) { 2000 case -SCTP_IERROR_NOMEM: 2001 goto nomem; 2002 2003 case -SCTP_IERROR_STALE_COOKIE: 2004 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 2005 err_chk_p); 2006 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2007 case -SCTP_IERROR_BAD_SIG: 2008 default: 2009 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2010 } 2011 } 2012 2013 /* Compare the tie_tag in cookie with the verification tag of 2014 * current association. 2015 */ 2016 action = sctp_tietags_compare(new_asoc, asoc); 2017 2018 switch (action) { 2019 case 'A': /* Association restart. */ 2020 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 2021 new_asoc); 2022 break; 2023 2024 case 'B': /* Collision case B. */ 2025 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 2026 new_asoc); 2027 break; 2028 2029 case 'C': /* Collision case C. */ 2030 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 2031 new_asoc); 2032 break; 2033 2034 case 'D': /* Collision case D. */ 2035 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 2036 new_asoc); 2037 break; 2038 2039 default: /* Discard packet for all others. */ 2040 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2041 break; 2042 } 2043 2044 /* Delete the tempory new association. */ 2045 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2046 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2047 2048 /* Restore association pointer to provide SCTP command interpeter 2049 * with a valid context in case it needs to manipulate 2050 * the queues */ 2051 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2052 SCTP_ASOC((struct sctp_association *)asoc)); 2053 2054 return retval; 2055 2056 nomem: 2057 return SCTP_DISPOSITION_NOMEM; 2058 } 2059 2060 /* 2061 * Process an ABORT. (SHUTDOWN-PENDING state) 2062 * 2063 * See sctp_sf_do_9_1_abort(). 2064 */ 2065 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2066 const struct sctp_endpoint *ep, 2067 const struct sctp_association *asoc, 2068 const sctp_subtype_t type, 2069 void *arg, 2070 sctp_cmd_seq_t *commands) 2071 { 2072 struct sctp_chunk *chunk = arg; 2073 2074 if (!sctp_vtag_verify_either(chunk, asoc)) 2075 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2076 2077 /* Make sure that the ABORT chunk has a valid length. 2078 * Since this is an ABORT chunk, we have to discard it 2079 * because of the following text: 2080 * RFC 2960, Section 3.3.7 2081 * If an endpoint receives an ABORT with a format error or for an 2082 * association that doesn't exist, it MUST silently discard it. 2083 * Because the length is "invalid", we can't really discard just 2084 * as we do not know its true length. So, to be safe, discard the 2085 * packet. 2086 */ 2087 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2088 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2089 2090 /* ADD-IP: Special case for ABORT chunks 2091 * F4) One special consideration is that ABORT Chunks arriving 2092 * destined to the IP address being deleted MUST be 2093 * ignored (see Section 5.3.1 for further details). 2094 */ 2095 if (SCTP_ADDR_DEL == 2096 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2097 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2098 2099 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2100 } 2101 2102 /* 2103 * Process an ABORT. (SHUTDOWN-SENT state) 2104 * 2105 * See sctp_sf_do_9_1_abort(). 2106 */ 2107 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 2108 const struct sctp_association *asoc, 2109 const sctp_subtype_t type, 2110 void *arg, 2111 sctp_cmd_seq_t *commands) 2112 { 2113 struct sctp_chunk *chunk = arg; 2114 2115 if (!sctp_vtag_verify_either(chunk, asoc)) 2116 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2117 2118 /* Make sure that the ABORT chunk has a valid length. 2119 * Since this is an ABORT chunk, we have to discard it 2120 * because of the following text: 2121 * RFC 2960, Section 3.3.7 2122 * If an endpoint receives an ABORT with a format error or for an 2123 * association that doesn't exist, it MUST silently discard it. 2124 * Because the length is "invalid", we can't really discard just 2125 * as we do not know its true length. So, to be safe, discard the 2126 * packet. 2127 */ 2128 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2129 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2130 2131 /* ADD-IP: Special case for ABORT chunks 2132 * F4) One special consideration is that ABORT Chunks arriving 2133 * destined to the IP address being deleted MUST be 2134 * ignored (see Section 5.3.1 for further details). 2135 */ 2136 if (SCTP_ADDR_DEL == 2137 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2138 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2139 2140 /* Stop the T2-shutdown timer. */ 2141 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2142 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2143 2144 /* Stop the T5-shutdown guard timer. */ 2145 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2146 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2147 2148 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2149 } 2150 2151 /* 2152 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2153 * 2154 * See sctp_sf_do_9_1_abort(). 2155 */ 2156 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2157 const struct sctp_endpoint *ep, 2158 const struct sctp_association *asoc, 2159 const sctp_subtype_t type, 2160 void *arg, 2161 sctp_cmd_seq_t *commands) 2162 { 2163 /* The same T2 timer, so we should be able to use 2164 * common function with the SHUTDOWN-SENT state. 2165 */ 2166 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2167 } 2168 2169 /* 2170 * Handle an Error received in COOKIE_ECHOED state. 2171 * 2172 * Only handle the error type of stale COOKIE Error, the other errors will 2173 * be ignored. 2174 * 2175 * Inputs 2176 * (endpoint, asoc, chunk) 2177 * 2178 * Outputs 2179 * (asoc, reply_msg, msg_up, timers, counters) 2180 * 2181 * The return value is the disposition of the chunk. 2182 */ 2183 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2184 const struct sctp_association *asoc, 2185 const sctp_subtype_t type, 2186 void *arg, 2187 sctp_cmd_seq_t *commands) 2188 { 2189 struct sctp_chunk *chunk = arg; 2190 sctp_errhdr_t *err; 2191 2192 if (!sctp_vtag_verify(chunk, asoc)) 2193 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2194 2195 /* Make sure that the ERROR chunk has a valid length. 2196 * The parameter walking depends on this as well. 2197 */ 2198 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2199 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2200 commands); 2201 2202 /* Process the error here */ 2203 /* FUTURE FIXME: When PR-SCTP related and other optional 2204 * parms are emitted, this will have to change to handle multiple 2205 * errors. 2206 */ 2207 sctp_walk_errors(err, chunk->chunk_hdr) { 2208 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2209 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2210 arg, commands); 2211 } 2212 2213 /* It is possible to have malformed error causes, and that 2214 * will cause us to end the walk early. However, since 2215 * we are discarding the packet, there should be no adverse 2216 * affects. 2217 */ 2218 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2219 } 2220 2221 /* 2222 * Handle a Stale COOKIE Error 2223 * 2224 * Section: 5.2.6 Handle Stale COOKIE Error 2225 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2226 * one of the following three alternatives. 2227 * ... 2228 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2229 * Preservative parameter requesting an extension to the lifetime of 2230 * the State Cookie. When calculating the time extension, an 2231 * implementation SHOULD use the RTT information measured based on the 2232 * previous COOKIE ECHO / ERROR exchange, and should add no more 2233 * than 1 second beyond the measured RTT, due to long State Cookie 2234 * lifetimes making the endpoint more subject to a replay attack. 2235 * 2236 * Verification Tag: Not explicit, but safe to ignore. 2237 * 2238 * Inputs 2239 * (endpoint, asoc, chunk) 2240 * 2241 * Outputs 2242 * (asoc, reply_msg, msg_up, timers, counters) 2243 * 2244 * The return value is the disposition of the chunk. 2245 */ 2246 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2247 const struct sctp_association *asoc, 2248 const sctp_subtype_t type, 2249 void *arg, 2250 sctp_cmd_seq_t *commands) 2251 { 2252 struct sctp_chunk *chunk = arg; 2253 time_t stale; 2254 sctp_cookie_preserve_param_t bht; 2255 sctp_errhdr_t *err; 2256 struct sctp_chunk *reply; 2257 struct sctp_bind_addr *bp; 2258 int attempts = asoc->init_err_counter + 1; 2259 2260 if (attempts > asoc->max_init_attempts) { 2261 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2262 SCTP_ERROR(ETIMEDOUT)); 2263 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2264 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2265 return SCTP_DISPOSITION_DELETE_TCB; 2266 } 2267 2268 err = (sctp_errhdr_t *)(chunk->skb->data); 2269 2270 /* When calculating the time extension, an implementation 2271 * SHOULD use the RTT information measured based on the 2272 * previous COOKIE ECHO / ERROR exchange, and should add no 2273 * more than 1 second beyond the measured RTT, due to long 2274 * State Cookie lifetimes making the endpoint more subject to 2275 * a replay attack. 2276 * Measure of Staleness's unit is usec. (1/1000000 sec) 2277 * Suggested Cookie Life-span Increment's unit is msec. 2278 * (1/1000 sec) 2279 * In general, if you use the suggested cookie life, the value 2280 * found in the field of measure of staleness should be doubled 2281 * to give ample time to retransmit the new cookie and thus 2282 * yield a higher probability of success on the reattempt. 2283 */ 2284 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2285 stale = (stale * 2) / 1000; 2286 2287 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2288 bht.param_hdr.length = htons(sizeof(bht)); 2289 bht.lifespan_increment = htonl(stale); 2290 2291 /* Build that new INIT chunk. */ 2292 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2293 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2294 if (!reply) 2295 goto nomem; 2296 2297 sctp_addto_chunk(reply, sizeof(bht), &bht); 2298 2299 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2300 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2301 2302 /* Stop pending T3-rtx and heartbeat timers */ 2303 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2304 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2305 2306 /* Delete non-primary peer ip addresses since we are transitioning 2307 * back to the COOKIE-WAIT state 2308 */ 2309 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2310 2311 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2312 * resend 2313 */ 2314 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2315 SCTP_TRANSPORT(asoc->peer.primary_path)); 2316 2317 /* Cast away the const modifier, as we want to just 2318 * rerun it through as a sideffect. 2319 */ 2320 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2321 2322 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2323 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2324 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2325 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2326 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2327 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2328 2329 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2330 2331 return SCTP_DISPOSITION_CONSUME; 2332 2333 nomem: 2334 return SCTP_DISPOSITION_NOMEM; 2335 } 2336 2337 /* 2338 * Process an ABORT. 2339 * 2340 * Section: 9.1 2341 * After checking the Verification Tag, the receiving endpoint shall 2342 * remove the association from its record, and shall report the 2343 * termination to its upper layer. 2344 * 2345 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2346 * B) Rules for packet carrying ABORT: 2347 * 2348 * - The endpoint shall always fill in the Verification Tag field of the 2349 * outbound packet with the destination endpoint's tag value if it 2350 * is known. 2351 * 2352 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2353 * MUST follow the procedure described in Section 8.4. 2354 * 2355 * - The receiver MUST accept the packet if the Verification Tag 2356 * matches either its own tag, OR the tag of its peer. Otherwise, the 2357 * receiver MUST silently discard the packet and take no further 2358 * action. 2359 * 2360 * Inputs 2361 * (endpoint, asoc, chunk) 2362 * 2363 * Outputs 2364 * (asoc, reply_msg, msg_up, timers, counters) 2365 * 2366 * The return value is the disposition of the chunk. 2367 */ 2368 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2369 const struct sctp_association *asoc, 2370 const sctp_subtype_t type, 2371 void *arg, 2372 sctp_cmd_seq_t *commands) 2373 { 2374 struct sctp_chunk *chunk = arg; 2375 2376 if (!sctp_vtag_verify_either(chunk, asoc)) 2377 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2378 2379 /* Make sure that the ABORT chunk has a valid length. 2380 * Since this is an ABORT chunk, we have to discard it 2381 * because of the following text: 2382 * RFC 2960, Section 3.3.7 2383 * If an endpoint receives an ABORT with a format error or for an 2384 * association that doesn't exist, it MUST silently discard it. 2385 * Because the length is "invalid", we can't really discard just 2386 * as we do not know its true length. So, to be safe, discard the 2387 * packet. 2388 */ 2389 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2390 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2391 2392 /* ADD-IP: Special case for ABORT chunks 2393 * F4) One special consideration is that ABORT Chunks arriving 2394 * destined to the IP address being deleted MUST be 2395 * ignored (see Section 5.3.1 for further details). 2396 */ 2397 if (SCTP_ADDR_DEL == 2398 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2399 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2400 2401 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2402 } 2403 2404 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2405 const struct sctp_association *asoc, 2406 const sctp_subtype_t type, 2407 void *arg, 2408 sctp_cmd_seq_t *commands) 2409 { 2410 struct sctp_chunk *chunk = arg; 2411 unsigned int len; 2412 __be16 error = SCTP_ERROR_NO_ERROR; 2413 2414 /* See if we have an error cause code in the chunk. */ 2415 len = ntohs(chunk->chunk_hdr->length); 2416 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2417 2418 sctp_errhdr_t *err; 2419 sctp_walk_errors(err, chunk->chunk_hdr); 2420 if ((void *)err != (void *)chunk->chunk_end) 2421 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2422 2423 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2424 } 2425 2426 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2427 /* ASSOC_FAILED will DELETE_TCB. */ 2428 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2429 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2430 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2431 2432 return SCTP_DISPOSITION_ABORT; 2433 } 2434 2435 /* 2436 * Process an ABORT. (COOKIE-WAIT state) 2437 * 2438 * See sctp_sf_do_9_1_abort() above. 2439 */ 2440 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2441 const struct sctp_association *asoc, 2442 const sctp_subtype_t type, 2443 void *arg, 2444 sctp_cmd_seq_t *commands) 2445 { 2446 struct sctp_chunk *chunk = arg; 2447 unsigned int len; 2448 __be16 error = SCTP_ERROR_NO_ERROR; 2449 2450 if (!sctp_vtag_verify_either(chunk, asoc)) 2451 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2452 2453 /* Make sure that the ABORT chunk has a valid length. 2454 * Since this is an ABORT chunk, we have to discard it 2455 * because of the following text: 2456 * RFC 2960, Section 3.3.7 2457 * If an endpoint receives an ABORT with a format error or for an 2458 * association that doesn't exist, it MUST silently discard it. 2459 * Because the length is "invalid", we can't really discard just 2460 * as we do not know its true length. So, to be safe, discard the 2461 * packet. 2462 */ 2463 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2464 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2465 2466 /* See if we have an error cause code in the chunk. */ 2467 len = ntohs(chunk->chunk_hdr->length); 2468 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2469 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2470 2471 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, 2472 chunk->transport); 2473 } 2474 2475 /* 2476 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2477 */ 2478 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2479 const struct sctp_association *asoc, 2480 const sctp_subtype_t type, 2481 void *arg, 2482 sctp_cmd_seq_t *commands) 2483 { 2484 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, 2485 ENOPROTOOPT, asoc, 2486 (struct sctp_transport *)arg); 2487 } 2488 2489 /* 2490 * Process an ABORT. (COOKIE-ECHOED state) 2491 */ 2492 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2493 const struct sctp_association *asoc, 2494 const sctp_subtype_t type, 2495 void *arg, 2496 sctp_cmd_seq_t *commands) 2497 { 2498 /* There is a single T1 timer, so we should be able to use 2499 * common function with the COOKIE-WAIT state. 2500 */ 2501 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2502 } 2503 2504 /* 2505 * Stop T1 timer and abort association with "INIT failed". 2506 * 2507 * This is common code called by several sctp_sf_*_abort() functions above. 2508 */ 2509 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2510 __be16 error, int sk_err, 2511 const struct sctp_association *asoc, 2512 struct sctp_transport *transport) 2513 { 2514 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2515 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2516 SCTP_STATE(SCTP_STATE_CLOSED)); 2517 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2518 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2519 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2520 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2521 /* CMD_INIT_FAILED will DELETE_TCB. */ 2522 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2523 SCTP_PERR(error)); 2524 return SCTP_DISPOSITION_ABORT; 2525 } 2526 2527 /* 2528 * sctp_sf_do_9_2_shut 2529 * 2530 * Section: 9.2 2531 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2532 * - enter the SHUTDOWN-RECEIVED state, 2533 * 2534 * - stop accepting new data from its SCTP user 2535 * 2536 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2537 * that all its outstanding DATA chunks have been received by the 2538 * SHUTDOWN sender. 2539 * 2540 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2541 * send a SHUTDOWN in response to a ULP request. And should discard 2542 * subsequent SHUTDOWN chunks. 2543 * 2544 * If there are still outstanding DATA chunks left, the SHUTDOWN 2545 * receiver shall continue to follow normal data transmission 2546 * procedures defined in Section 6 until all outstanding DATA chunks 2547 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2548 * new data from its SCTP user. 2549 * 2550 * Verification Tag: 8.5 Verification Tag [Normal verification] 2551 * 2552 * Inputs 2553 * (endpoint, asoc, chunk) 2554 * 2555 * Outputs 2556 * (asoc, reply_msg, msg_up, timers, counters) 2557 * 2558 * The return value is the disposition of the chunk. 2559 */ 2560 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2561 const struct sctp_association *asoc, 2562 const sctp_subtype_t type, 2563 void *arg, 2564 sctp_cmd_seq_t *commands) 2565 { 2566 struct sctp_chunk *chunk = arg; 2567 sctp_shutdownhdr_t *sdh; 2568 sctp_disposition_t disposition; 2569 struct sctp_ulpevent *ev; 2570 __u32 ctsn; 2571 2572 if (!sctp_vtag_verify(chunk, asoc)) 2573 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2574 2575 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2576 if (!sctp_chunk_length_valid(chunk, 2577 sizeof(struct sctp_shutdown_chunk_t))) 2578 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2579 commands); 2580 2581 /* Convert the elaborate header. */ 2582 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2583 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2584 chunk->subh.shutdown_hdr = sdh; 2585 ctsn = ntohl(sdh->cum_tsn_ack); 2586 2587 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2588 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2589 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2590 return SCTP_DISPOSITION_DISCARD; 2591 } 2592 2593 /* If Cumulative TSN Ack beyond the max tsn currently 2594 * send, terminating the association and respond to the 2595 * sender with an ABORT. 2596 */ 2597 if (!TSN_lt(ctsn, asoc->next_tsn)) 2598 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 2599 2600 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2601 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2602 * inform the application that it should cease sending data. 2603 */ 2604 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2605 if (!ev) { 2606 disposition = SCTP_DISPOSITION_NOMEM; 2607 goto out; 2608 } 2609 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2610 2611 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2612 * - enter the SHUTDOWN-RECEIVED state, 2613 * - stop accepting new data from its SCTP user 2614 * 2615 * [This is implicit in the new state.] 2616 */ 2617 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2618 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2619 disposition = SCTP_DISPOSITION_CONSUME; 2620 2621 if (sctp_outq_is_empty(&asoc->outqueue)) { 2622 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2623 arg, commands); 2624 } 2625 2626 if (SCTP_DISPOSITION_NOMEM == disposition) 2627 goto out; 2628 2629 /* - verify, by checking the Cumulative TSN Ack field of the 2630 * chunk, that all its outstanding DATA chunks have been 2631 * received by the SHUTDOWN sender. 2632 */ 2633 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2634 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2635 2636 out: 2637 return disposition; 2638 } 2639 2640 /* 2641 * sctp_sf_do_9_2_shut_ctsn 2642 * 2643 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2644 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2645 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2646 * MUST be processed. 2647 */ 2648 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep, 2649 const struct sctp_association *asoc, 2650 const sctp_subtype_t type, 2651 void *arg, 2652 sctp_cmd_seq_t *commands) 2653 { 2654 struct sctp_chunk *chunk = arg; 2655 sctp_shutdownhdr_t *sdh; 2656 __u32 ctsn; 2657 2658 if (!sctp_vtag_verify(chunk, asoc)) 2659 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2660 2661 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2662 if (!sctp_chunk_length_valid(chunk, 2663 sizeof(struct sctp_shutdown_chunk_t))) 2664 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2665 commands); 2666 2667 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2668 ctsn = ntohl(sdh->cum_tsn_ack); 2669 2670 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2671 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2672 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2673 return SCTP_DISPOSITION_DISCARD; 2674 } 2675 2676 /* If Cumulative TSN Ack beyond the max tsn currently 2677 * send, terminating the association and respond to the 2678 * sender with an ABORT. 2679 */ 2680 if (!TSN_lt(ctsn, asoc->next_tsn)) 2681 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 2682 2683 /* verify, by checking the Cumulative TSN Ack field of the 2684 * chunk, that all its outstanding DATA chunks have been 2685 * received by the SHUTDOWN sender. 2686 */ 2687 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2688 SCTP_BE32(sdh->cum_tsn_ack)); 2689 2690 return SCTP_DISPOSITION_CONSUME; 2691 } 2692 2693 /* RFC 2960 9.2 2694 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2695 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2696 * transport addresses (either in the IP addresses or in the INIT chunk) 2697 * that belong to this association, it should discard the INIT chunk and 2698 * retransmit the SHUTDOWN ACK chunk. 2699 */ 2700 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2701 const struct sctp_association *asoc, 2702 const sctp_subtype_t type, 2703 void *arg, 2704 sctp_cmd_seq_t *commands) 2705 { 2706 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2707 struct sctp_chunk *reply; 2708 2709 /* Make sure that the chunk has a valid length */ 2710 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2711 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2712 commands); 2713 2714 /* Since we are not going to really process this INIT, there 2715 * is no point in verifying chunk boundries. Just generate 2716 * the SHUTDOWN ACK. 2717 */ 2718 reply = sctp_make_shutdown_ack(asoc, chunk); 2719 if (NULL == reply) 2720 goto nomem; 2721 2722 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2723 * the T2-SHUTDOWN timer. 2724 */ 2725 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2726 2727 /* and restart the T2-shutdown timer. */ 2728 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2729 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2730 2731 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2732 2733 return SCTP_DISPOSITION_CONSUME; 2734 nomem: 2735 return SCTP_DISPOSITION_NOMEM; 2736 } 2737 2738 /* 2739 * sctp_sf_do_ecn_cwr 2740 * 2741 * Section: Appendix A: Explicit Congestion Notification 2742 * 2743 * CWR: 2744 * 2745 * RFC 2481 details a specific bit for a sender to send in the header of 2746 * its next outbound TCP segment to indicate to its peer that it has 2747 * reduced its congestion window. This is termed the CWR bit. For 2748 * SCTP the same indication is made by including the CWR chunk. 2749 * This chunk contains one data element, i.e. the TSN number that 2750 * was sent in the ECNE chunk. This element represents the lowest 2751 * TSN number in the datagram that was originally marked with the 2752 * CE bit. 2753 * 2754 * Verification Tag: 8.5 Verification Tag [Normal verification] 2755 * Inputs 2756 * (endpoint, asoc, chunk) 2757 * 2758 * Outputs 2759 * (asoc, reply_msg, msg_up, timers, counters) 2760 * 2761 * The return value is the disposition of the chunk. 2762 */ 2763 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2764 const struct sctp_association *asoc, 2765 const sctp_subtype_t type, 2766 void *arg, 2767 sctp_cmd_seq_t *commands) 2768 { 2769 sctp_cwrhdr_t *cwr; 2770 struct sctp_chunk *chunk = arg; 2771 u32 lowest_tsn; 2772 2773 if (!sctp_vtag_verify(chunk, asoc)) 2774 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2775 2776 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2777 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2778 commands); 2779 2780 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2781 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2782 2783 lowest_tsn = ntohl(cwr->lowest_tsn); 2784 2785 /* Does this CWR ack the last sent congestion notification? */ 2786 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2787 /* Stop sending ECNE. */ 2788 sctp_add_cmd_sf(commands, 2789 SCTP_CMD_ECN_CWR, 2790 SCTP_U32(lowest_tsn)); 2791 } 2792 return SCTP_DISPOSITION_CONSUME; 2793 } 2794 2795 /* 2796 * sctp_sf_do_ecne 2797 * 2798 * Section: Appendix A: Explicit Congestion Notification 2799 * 2800 * ECN-Echo 2801 * 2802 * RFC 2481 details a specific bit for a receiver to send back in its 2803 * TCP acknowledgements to notify the sender of the Congestion 2804 * Experienced (CE) bit having arrived from the network. For SCTP this 2805 * same indication is made by including the ECNE chunk. This chunk 2806 * contains one data element, i.e. the lowest TSN associated with the IP 2807 * datagram marked with the CE bit..... 2808 * 2809 * Verification Tag: 8.5 Verification Tag [Normal verification] 2810 * Inputs 2811 * (endpoint, asoc, chunk) 2812 * 2813 * Outputs 2814 * (asoc, reply_msg, msg_up, timers, counters) 2815 * 2816 * The return value is the disposition of the chunk. 2817 */ 2818 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2819 const struct sctp_association *asoc, 2820 const sctp_subtype_t type, 2821 void *arg, 2822 sctp_cmd_seq_t *commands) 2823 { 2824 sctp_ecnehdr_t *ecne; 2825 struct sctp_chunk *chunk = arg; 2826 2827 if (!sctp_vtag_verify(chunk, asoc)) 2828 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2829 2830 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2831 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2832 commands); 2833 2834 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2835 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2836 2837 /* If this is a newer ECNE than the last CWR packet we sent out */ 2838 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2839 SCTP_U32(ntohl(ecne->lowest_tsn))); 2840 2841 return SCTP_DISPOSITION_CONSUME; 2842 } 2843 2844 /* 2845 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2846 * 2847 * The SCTP endpoint MUST always acknowledge the reception of each valid 2848 * DATA chunk. 2849 * 2850 * The guidelines on delayed acknowledgement algorithm specified in 2851 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2852 * acknowledgement SHOULD be generated for at least every second packet 2853 * (not every second DATA chunk) received, and SHOULD be generated within 2854 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2855 * situations it may be beneficial for an SCTP transmitter to be more 2856 * conservative than the algorithms detailed in this document allow. 2857 * However, an SCTP transmitter MUST NOT be more aggressive than the 2858 * following algorithms allow. 2859 * 2860 * A SCTP receiver MUST NOT generate more than one SACK for every 2861 * incoming packet, other than to update the offered window as the 2862 * receiving application consumes new data. 2863 * 2864 * Verification Tag: 8.5 Verification Tag [Normal verification] 2865 * 2866 * Inputs 2867 * (endpoint, asoc, chunk) 2868 * 2869 * Outputs 2870 * (asoc, reply_msg, msg_up, timers, counters) 2871 * 2872 * The return value is the disposition of the chunk. 2873 */ 2874 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2875 const struct sctp_association *asoc, 2876 const sctp_subtype_t type, 2877 void *arg, 2878 sctp_cmd_seq_t *commands) 2879 { 2880 struct sctp_chunk *chunk = arg; 2881 sctp_arg_t force = SCTP_NOFORCE(); 2882 int error; 2883 2884 if (!sctp_vtag_verify(chunk, asoc)) { 2885 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2886 SCTP_NULL()); 2887 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2888 } 2889 2890 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2891 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2892 commands); 2893 2894 error = sctp_eat_data(asoc, chunk, commands ); 2895 switch (error) { 2896 case SCTP_IERROR_NO_ERROR: 2897 break; 2898 case SCTP_IERROR_HIGH_TSN: 2899 case SCTP_IERROR_BAD_STREAM: 2900 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2901 goto discard_noforce; 2902 case SCTP_IERROR_DUP_TSN: 2903 case SCTP_IERROR_IGNORE_TSN: 2904 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2905 goto discard_force; 2906 case SCTP_IERROR_NO_DATA: 2907 goto consume; 2908 case SCTP_IERROR_PROTO_VIOLATION: 2909 return sctp_sf_abort_violation(ep, asoc, chunk, commands, 2910 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2911 default: 2912 BUG(); 2913 } 2914 2915 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2916 force = SCTP_FORCE(); 2917 2918 if (asoc->autoclose) { 2919 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2920 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2921 } 2922 2923 /* If this is the last chunk in a packet, we need to count it 2924 * toward sack generation. Note that we need to SACK every 2925 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2926 * THEM. We elect to NOT generate SACK's if the chunk fails 2927 * the verification tag test. 2928 * 2929 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2930 * 2931 * The SCTP endpoint MUST always acknowledge the reception of 2932 * each valid DATA chunk. 2933 * 2934 * The guidelines on delayed acknowledgement algorithm 2935 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2936 * Specifically, an acknowledgement SHOULD be generated for at 2937 * least every second packet (not every second DATA chunk) 2938 * received, and SHOULD be generated within 200 ms of the 2939 * arrival of any unacknowledged DATA chunk. In some 2940 * situations it may be beneficial for an SCTP transmitter to 2941 * be more conservative than the algorithms detailed in this 2942 * document allow. However, an SCTP transmitter MUST NOT be 2943 * more aggressive than the following algorithms allow. 2944 */ 2945 if (chunk->end_of_packet) 2946 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 2947 2948 return SCTP_DISPOSITION_CONSUME; 2949 2950 discard_force: 2951 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2952 * 2953 * When a packet arrives with duplicate DATA chunk(s) and with 2954 * no new DATA chunk(s), the endpoint MUST immediately send a 2955 * SACK with no delay. If a packet arrives with duplicate 2956 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2957 * MAY immediately send a SACK. Normally receipt of duplicate 2958 * DATA chunks will occur when the original SACK chunk was lost 2959 * and the peer's RTO has expired. The duplicate TSN number(s) 2960 * SHOULD be reported in the SACK as duplicate. 2961 */ 2962 /* In our case, we split the MAY SACK advice up whether or not 2963 * the last chunk is a duplicate.' 2964 */ 2965 if (chunk->end_of_packet) 2966 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2967 return SCTP_DISPOSITION_DISCARD; 2968 2969 discard_noforce: 2970 if (chunk->end_of_packet) 2971 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 2972 2973 return SCTP_DISPOSITION_DISCARD; 2974 consume: 2975 return SCTP_DISPOSITION_CONSUME; 2976 2977 } 2978 2979 /* 2980 * sctp_sf_eat_data_fast_4_4 2981 * 2982 * Section: 4 (4) 2983 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2984 * DATA chunks without delay. 2985 * 2986 * Verification Tag: 8.5 Verification Tag [Normal verification] 2987 * Inputs 2988 * (endpoint, asoc, chunk) 2989 * 2990 * Outputs 2991 * (asoc, reply_msg, msg_up, timers, counters) 2992 * 2993 * The return value is the disposition of the chunk. 2994 */ 2995 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2996 const struct sctp_association *asoc, 2997 const sctp_subtype_t type, 2998 void *arg, 2999 sctp_cmd_seq_t *commands) 3000 { 3001 struct sctp_chunk *chunk = arg; 3002 int error; 3003 3004 if (!sctp_vtag_verify(chunk, asoc)) { 3005 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3006 SCTP_NULL()); 3007 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3008 } 3009 3010 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3011 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3012 commands); 3013 3014 error = sctp_eat_data(asoc, chunk, commands ); 3015 switch (error) { 3016 case SCTP_IERROR_NO_ERROR: 3017 case SCTP_IERROR_HIGH_TSN: 3018 case SCTP_IERROR_DUP_TSN: 3019 case SCTP_IERROR_IGNORE_TSN: 3020 case SCTP_IERROR_BAD_STREAM: 3021 break; 3022 case SCTP_IERROR_NO_DATA: 3023 goto consume; 3024 case SCTP_IERROR_PROTO_VIOLATION: 3025 return sctp_sf_abort_violation(ep, asoc, chunk, commands, 3026 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3027 default: 3028 BUG(); 3029 } 3030 3031 /* Go a head and force a SACK, since we are shutting down. */ 3032 3033 /* Implementor's Guide. 3034 * 3035 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3036 * respond to each received packet containing one or more DATA chunk(s) 3037 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3038 */ 3039 if (chunk->end_of_packet) { 3040 /* We must delay the chunk creation since the cumulative 3041 * TSN has not been updated yet. 3042 */ 3043 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3044 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3045 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3046 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3047 } 3048 3049 consume: 3050 return SCTP_DISPOSITION_CONSUME; 3051 } 3052 3053 /* 3054 * Section: 6.2 Processing a Received SACK 3055 * D) Any time a SACK arrives, the endpoint performs the following: 3056 * 3057 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3058 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3059 * increasing, a SACK whose Cumulative TSN Ack is less than the 3060 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3061 * 3062 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3063 * of bytes still outstanding after processing the Cumulative TSN Ack 3064 * and the Gap Ack Blocks. 3065 * 3066 * iii) If the SACK is missing a TSN that was previously 3067 * acknowledged via a Gap Ack Block (e.g., the data receiver 3068 * reneged on the data), then mark the corresponding DATA chunk 3069 * as available for retransmit: Mark it as missing for fast 3070 * retransmit as described in Section 7.2.4 and if no retransmit 3071 * timer is running for the destination address to which the DATA 3072 * chunk was originally transmitted, then T3-rtx is started for 3073 * that destination address. 3074 * 3075 * Verification Tag: 8.5 Verification Tag [Normal verification] 3076 * 3077 * Inputs 3078 * (endpoint, asoc, chunk) 3079 * 3080 * Outputs 3081 * (asoc, reply_msg, msg_up, timers, counters) 3082 * 3083 * The return value is the disposition of the chunk. 3084 */ 3085 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 3086 const struct sctp_association *asoc, 3087 const sctp_subtype_t type, 3088 void *arg, 3089 sctp_cmd_seq_t *commands) 3090 { 3091 struct sctp_chunk *chunk = arg; 3092 sctp_sackhdr_t *sackh; 3093 __u32 ctsn; 3094 3095 if (!sctp_vtag_verify(chunk, asoc)) 3096 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3097 3098 /* Make sure that the SACK chunk has a valid length. */ 3099 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3100 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3101 commands); 3102 3103 /* Pull the SACK chunk from the data buffer */ 3104 sackh = sctp_sm_pull_sack(chunk); 3105 /* Was this a bogus SACK? */ 3106 if (!sackh) 3107 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3108 chunk->subh.sack_hdr = sackh; 3109 ctsn = ntohl(sackh->cum_tsn_ack); 3110 3111 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3112 * Ack Point, then drop the SACK. Since Cumulative TSN 3113 * Ack is monotonically increasing, a SACK whose 3114 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3115 * Point indicates an out-of-order SACK. 3116 */ 3117 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3118 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3119 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3120 return SCTP_DISPOSITION_DISCARD; 3121 } 3122 3123 /* If Cumulative TSN Ack beyond the max tsn currently 3124 * send, terminating the association and respond to the 3125 * sender with an ABORT. 3126 */ 3127 if (!TSN_lt(ctsn, asoc->next_tsn)) 3128 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 3129 3130 /* Return this SACK for further processing. */ 3131 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 3132 3133 /* Note: We do the rest of the work on the PROCESS_SACK 3134 * sideeffect. 3135 */ 3136 return SCTP_DISPOSITION_CONSUME; 3137 } 3138 3139 /* 3140 * Generate an ABORT in response to a packet. 3141 * 3142 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3143 * 3144 * 8) The receiver should respond to the sender of the OOTB packet with 3145 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3146 * MUST fill in the Verification Tag field of the outbound packet 3147 * with the value found in the Verification Tag field of the OOTB 3148 * packet and set the T-bit in the Chunk Flags to indicate that the 3149 * Verification Tag is reflected. After sending this ABORT, the 3150 * receiver of the OOTB packet shall discard the OOTB packet and take 3151 * no further action. 3152 * 3153 * Verification Tag: 3154 * 3155 * The return value is the disposition of the chunk. 3156 */ 3157 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 3158 const struct sctp_association *asoc, 3159 const sctp_subtype_t type, 3160 void *arg, 3161 sctp_cmd_seq_t *commands) 3162 { 3163 struct sctp_packet *packet = NULL; 3164 struct sctp_chunk *chunk = arg; 3165 struct sctp_chunk *abort; 3166 3167 packet = sctp_ootb_pkt_new(asoc, chunk); 3168 3169 if (packet) { 3170 /* Make an ABORT. The T bit will be set if the asoc 3171 * is NULL. 3172 */ 3173 abort = sctp_make_abort(asoc, chunk, 0); 3174 if (!abort) { 3175 sctp_ootb_pkt_free(packet); 3176 return SCTP_DISPOSITION_NOMEM; 3177 } 3178 3179 /* Reflect vtag if T-Bit is set */ 3180 if (sctp_test_T_bit(abort)) 3181 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3182 3183 /* Set the skb to the belonging sock for accounting. */ 3184 abort->skb->sk = ep->base.sk; 3185 3186 sctp_packet_append_chunk(packet, abort); 3187 3188 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3189 SCTP_PACKET(packet)); 3190 3191 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3192 3193 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3194 return SCTP_DISPOSITION_CONSUME; 3195 } 3196 3197 return SCTP_DISPOSITION_NOMEM; 3198 } 3199 3200 /* 3201 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3202 * event as ULP notification for each cause included in the chunk. 3203 * 3204 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3205 * 3206 * The return value is the disposition of the chunk. 3207 */ 3208 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 3209 const struct sctp_association *asoc, 3210 const sctp_subtype_t type, 3211 void *arg, 3212 sctp_cmd_seq_t *commands) 3213 { 3214 struct sctp_chunk *chunk = arg; 3215 sctp_errhdr_t *err; 3216 3217 if (!sctp_vtag_verify(chunk, asoc)) 3218 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3219 3220 /* Make sure that the ERROR chunk has a valid length. */ 3221 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3222 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3223 commands); 3224 sctp_walk_errors(err, chunk->chunk_hdr); 3225 if ((void *)err != (void *)chunk->chunk_end) 3226 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3227 (void *)err, commands); 3228 3229 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3230 SCTP_CHUNK(chunk)); 3231 3232 return SCTP_DISPOSITION_CONSUME; 3233 } 3234 3235 /* 3236 * Process an inbound SHUTDOWN ACK. 3237 * 3238 * From Section 9.2: 3239 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3240 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3241 * peer, and remove all record of the association. 3242 * 3243 * The return value is the disposition. 3244 */ 3245 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3246 const struct sctp_association *asoc, 3247 const sctp_subtype_t type, 3248 void *arg, 3249 sctp_cmd_seq_t *commands) 3250 { 3251 struct sctp_chunk *chunk = arg; 3252 struct sctp_chunk *reply; 3253 struct sctp_ulpevent *ev; 3254 3255 if (!sctp_vtag_verify(chunk, asoc)) 3256 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3257 3258 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3259 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3260 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3261 commands); 3262 /* 10.2 H) SHUTDOWN COMPLETE notification 3263 * 3264 * When SCTP completes the shutdown procedures (section 9.2) this 3265 * notification is passed to the upper layer. 3266 */ 3267 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3268 0, 0, 0, NULL, GFP_ATOMIC); 3269 if (!ev) 3270 goto nomem; 3271 3272 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3273 reply = sctp_make_shutdown_complete(asoc, chunk); 3274 if (!reply) 3275 goto nomem_chunk; 3276 3277 /* Do all the commands now (after allocation), so that we 3278 * have consistent state if memory allocation failes 3279 */ 3280 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3281 3282 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3283 * stop the T2-shutdown timer, 3284 */ 3285 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3286 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3287 3288 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3289 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3290 3291 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3292 SCTP_STATE(SCTP_STATE_CLOSED)); 3293 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3294 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3295 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3296 3297 /* ...and remove all record of the association. */ 3298 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3299 return SCTP_DISPOSITION_DELETE_TCB; 3300 3301 nomem_chunk: 3302 sctp_ulpevent_free(ev); 3303 nomem: 3304 return SCTP_DISPOSITION_NOMEM; 3305 } 3306 3307 /* 3308 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3309 * 3310 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3311 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3312 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3313 * packet must fill in the Verification Tag field of the outbound 3314 * packet with the Verification Tag received in the SHUTDOWN ACK and 3315 * set the T-bit in the Chunk Flags to indicate that the Verification 3316 * Tag is reflected. 3317 * 3318 * 8) The receiver should respond to the sender of the OOTB packet with 3319 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3320 * MUST fill in the Verification Tag field of the outbound packet 3321 * with the value found in the Verification Tag field of the OOTB 3322 * packet and set the T-bit in the Chunk Flags to indicate that the 3323 * Verification Tag is reflected. After sending this ABORT, the 3324 * receiver of the OOTB packet shall discard the OOTB packet and take 3325 * no further action. 3326 */ 3327 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3328 const struct sctp_association *asoc, 3329 const sctp_subtype_t type, 3330 void *arg, 3331 sctp_cmd_seq_t *commands) 3332 { 3333 struct sctp_chunk *chunk = arg; 3334 struct sk_buff *skb = chunk->skb; 3335 sctp_chunkhdr_t *ch; 3336 sctp_errhdr_t *err; 3337 __u8 *ch_end; 3338 int ootb_shut_ack = 0; 3339 int ootb_cookie_ack = 0; 3340 3341 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3342 3343 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3344 do { 3345 /* Report violation if the chunk is less then minimal */ 3346 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3347 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3348 commands); 3349 3350 /* Now that we know we at least have a chunk header, 3351 * do things that are type appropriate. 3352 */ 3353 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3354 ootb_shut_ack = 1; 3355 3356 /* RFC 2960, Section 3.3.7 3357 * Moreover, under any circumstances, an endpoint that 3358 * receives an ABORT MUST NOT respond to that ABORT by 3359 * sending an ABORT of its own. 3360 */ 3361 if (SCTP_CID_ABORT == ch->type) 3362 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3363 3364 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3365 * or a COOKIE ACK the SCTP Packet should be silently 3366 * discarded. 3367 */ 3368 3369 if (SCTP_CID_COOKIE_ACK == ch->type) 3370 ootb_cookie_ack = 1; 3371 3372 if (SCTP_CID_ERROR == ch->type) { 3373 sctp_walk_errors(err, ch) { 3374 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3375 ootb_cookie_ack = 1; 3376 break; 3377 } 3378 } 3379 } 3380 3381 /* Report violation if chunk len overflows */ 3382 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3383 if (ch_end > skb_tail_pointer(skb)) 3384 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3385 commands); 3386 3387 ch = (sctp_chunkhdr_t *) ch_end; 3388 } while (ch_end < skb_tail_pointer(skb)); 3389 3390 if (ootb_shut_ack) 3391 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3392 else if (ootb_cookie_ack) 3393 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3394 else 3395 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3396 } 3397 3398 /* 3399 * Handle an "Out of the blue" SHUTDOWN ACK. 3400 * 3401 * Section: 8.4 5, sctpimpguide 2.41. 3402 * 3403 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3404 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3405 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3406 * packet must fill in the Verification Tag field of the outbound 3407 * packet with the Verification Tag received in the SHUTDOWN ACK and 3408 * set the T-bit in the Chunk Flags to indicate that the Verification 3409 * Tag is reflected. 3410 * 3411 * Inputs 3412 * (endpoint, asoc, type, arg, commands) 3413 * 3414 * Outputs 3415 * (sctp_disposition_t) 3416 * 3417 * The return value is the disposition of the chunk. 3418 */ 3419 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3420 const struct sctp_association *asoc, 3421 const sctp_subtype_t type, 3422 void *arg, 3423 sctp_cmd_seq_t *commands) 3424 { 3425 struct sctp_packet *packet = NULL; 3426 struct sctp_chunk *chunk = arg; 3427 struct sctp_chunk *shut; 3428 3429 packet = sctp_ootb_pkt_new(asoc, chunk); 3430 3431 if (packet) { 3432 /* Make an SHUTDOWN_COMPLETE. 3433 * The T bit will be set if the asoc is NULL. 3434 */ 3435 shut = sctp_make_shutdown_complete(asoc, chunk); 3436 if (!shut) { 3437 sctp_ootb_pkt_free(packet); 3438 return SCTP_DISPOSITION_NOMEM; 3439 } 3440 3441 /* Reflect vtag if T-Bit is set */ 3442 if (sctp_test_T_bit(shut)) 3443 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3444 3445 /* Set the skb to the belonging sock for accounting. */ 3446 shut->skb->sk = ep->base.sk; 3447 3448 sctp_packet_append_chunk(packet, shut); 3449 3450 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3451 SCTP_PACKET(packet)); 3452 3453 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3454 3455 /* If the chunk length is invalid, we don't want to process 3456 * the reset of the packet. 3457 */ 3458 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3459 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3460 3461 /* We need to discard the rest of the packet to prevent 3462 * potential bomming attacks from additional bundled chunks. 3463 * This is documented in SCTP Threats ID. 3464 */ 3465 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3466 } 3467 3468 return SCTP_DISPOSITION_NOMEM; 3469 } 3470 3471 /* 3472 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3473 * 3474 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3475 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3476 * procedures in section 8.4 SHOULD be followed, in other words it 3477 * should be treated as an Out Of The Blue packet. 3478 * [This means that we do NOT check the Verification Tag on these 3479 * chunks. --piggy ] 3480 * 3481 */ 3482 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3483 const struct sctp_association *asoc, 3484 const sctp_subtype_t type, 3485 void *arg, 3486 sctp_cmd_seq_t *commands) 3487 { 3488 struct sctp_chunk *chunk = arg; 3489 3490 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3491 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3492 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3493 commands); 3494 3495 /* Although we do have an association in this case, it corresponds 3496 * to a restarted association. So the packet is treated as an OOTB 3497 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3498 * called with a NULL association. 3499 */ 3500 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3501 3502 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3503 } 3504 3505 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3506 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3507 const struct sctp_association *asoc, 3508 const sctp_subtype_t type, void *arg, 3509 sctp_cmd_seq_t *commands) 3510 { 3511 struct sctp_chunk *chunk = arg; 3512 struct sctp_chunk *asconf_ack = NULL; 3513 struct sctp_paramhdr *err_param = NULL; 3514 sctp_addiphdr_t *hdr; 3515 union sctp_addr_param *addr_param; 3516 __u32 serial; 3517 int length; 3518 3519 if (!sctp_vtag_verify(chunk, asoc)) { 3520 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3521 SCTP_NULL()); 3522 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3523 } 3524 3525 /* ADD-IP: Section 4.1.1 3526 * This chunk MUST be sent in an authenticated way by using 3527 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3528 * is received unauthenticated it MUST be silently discarded as 3529 * described in [I-D.ietf-tsvwg-sctp-auth]. 3530 */ 3531 if (!sctp_addip_noauth && !chunk->auth) 3532 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3533 3534 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3535 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3536 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3537 commands); 3538 3539 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3540 serial = ntohl(hdr->serial); 3541 3542 addr_param = (union sctp_addr_param *)hdr->params; 3543 length = ntohs(addr_param->p.length); 3544 if (length < sizeof(sctp_paramhdr_t)) 3545 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3546 (void *)addr_param, commands); 3547 3548 /* Verify the ASCONF chunk before processing it. */ 3549 if (!sctp_verify_asconf(asoc, 3550 (sctp_paramhdr_t *)((void *)addr_param + length), 3551 (void *)chunk->chunk_end, 3552 &err_param)) 3553 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3554 (void *)err_param, commands); 3555 3556 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3557 * the endpoint stored in a new association variable 3558 * 'Peer-Serial-Number'. 3559 */ 3560 if (serial == asoc->peer.addip_serial + 1) { 3561 /* If this is the first instance of ASCONF in the packet, 3562 * we can clean our old ASCONF-ACKs. 3563 */ 3564 if (!chunk->has_asconf) 3565 sctp_assoc_clean_asconf_ack_cache(asoc); 3566 3567 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3568 * expected, process the ASCONF as described below and after 3569 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3570 * the response packet and cache a copy of it (in the event it 3571 * later needs to be retransmitted). 3572 * 3573 * Essentially, do V1-V5. 3574 */ 3575 asconf_ack = sctp_process_asconf((struct sctp_association *) 3576 asoc, chunk); 3577 if (!asconf_ack) 3578 return SCTP_DISPOSITION_NOMEM; 3579 } else if (serial < asoc->peer.addip_serial + 1) { 3580 /* ADDIP 5.2 E2) 3581 * If the value found in the Sequence Number is less than the 3582 * ('Peer- Sequence-Number' + 1), simply skip to the next 3583 * ASCONF, and include in the outbound response packet 3584 * any previously cached ASCONF-ACK response that was 3585 * sent and saved that matches the Sequence Number of the 3586 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3587 * Chunk exists. This will occur when an older ASCONF 3588 * arrives out of order. In such a case, the receiver 3589 * should skip the ASCONF Chunk and not include ASCONF-ACK 3590 * Chunk for that chunk. 3591 */ 3592 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3593 if (!asconf_ack) 3594 return SCTP_DISPOSITION_DISCARD; 3595 3596 /* Reset the transport so that we select the correct one 3597 * this time around. This is to make sure that we don't 3598 * accidentally use a stale transport that's been removed. 3599 */ 3600 asconf_ack->transport = NULL; 3601 } else { 3602 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3603 * it must be either a stale packet or from an attacker. 3604 */ 3605 return SCTP_DISPOSITION_DISCARD; 3606 } 3607 3608 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3609 * containing the ASCONF-ACK Chunks MUST be the source address of 3610 * the SCTP packet that held the ASCONF Chunks. 3611 * 3612 * To do this properly, we'll set the destination address of the chunk 3613 * and at the transmit time, will try look up the transport to use. 3614 * Since ASCONFs may be bundled, the correct transport may not be 3615 * created until we process the entire packet, thus this workaround. 3616 */ 3617 asconf_ack->dest = chunk->source; 3618 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3619 if (asoc->new_transport) { 3620 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, 3621 commands); 3622 ((struct sctp_association *)asoc)->new_transport = NULL; 3623 } 3624 3625 return SCTP_DISPOSITION_CONSUME; 3626 } 3627 3628 /* 3629 * ADDIP Section 4.3 General rules for address manipulation 3630 * When building TLV parameters for the ASCONF Chunk that will add or 3631 * delete IP addresses the D0 to D13 rules should be applied: 3632 */ 3633 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3634 const struct sctp_association *asoc, 3635 const sctp_subtype_t type, void *arg, 3636 sctp_cmd_seq_t *commands) 3637 { 3638 struct sctp_chunk *asconf_ack = arg; 3639 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3640 struct sctp_chunk *abort; 3641 struct sctp_paramhdr *err_param = NULL; 3642 sctp_addiphdr_t *addip_hdr; 3643 __u32 sent_serial, rcvd_serial; 3644 3645 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3646 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3647 SCTP_NULL()); 3648 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3649 } 3650 3651 /* ADD-IP, Section 4.1.2: 3652 * This chunk MUST be sent in an authenticated way by using 3653 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3654 * is received unauthenticated it MUST be silently discarded as 3655 * described in [I-D.ietf-tsvwg-sctp-auth]. 3656 */ 3657 if (!sctp_addip_noauth && !asconf_ack->auth) 3658 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3659 3660 /* Make sure that the ADDIP chunk has a valid length. */ 3661 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3662 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3663 commands); 3664 3665 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3666 rcvd_serial = ntohl(addip_hdr->serial); 3667 3668 /* Verify the ASCONF-ACK chunk before processing it. */ 3669 if (!sctp_verify_asconf(asoc, 3670 (sctp_paramhdr_t *)addip_hdr->params, 3671 (void *)asconf_ack->chunk_end, 3672 &err_param)) 3673 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3674 (void *)err_param, commands); 3675 3676 if (last_asconf) { 3677 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3678 sent_serial = ntohl(addip_hdr->serial); 3679 } else { 3680 sent_serial = asoc->addip_serial - 1; 3681 } 3682 3683 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3684 * equal to the next serial number to be used but no ASCONF chunk is 3685 * outstanding the endpoint MUST ABORT the association. Note that a 3686 * sequence number is greater than if it is no more than 2^^31-1 3687 * larger than the current sequence number (using serial arithmetic). 3688 */ 3689 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3690 !(asoc->addip_last_asconf)) { 3691 abort = sctp_make_abort(asoc, asconf_ack, 3692 sizeof(sctp_errhdr_t)); 3693 if (abort) { 3694 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3695 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3696 SCTP_CHUNK(abort)); 3697 } 3698 /* We are going to ABORT, so we might as well stop 3699 * processing the rest of the chunks in the packet. 3700 */ 3701 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3702 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3703 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3704 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3705 SCTP_ERROR(ECONNABORTED)); 3706 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3707 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3708 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3709 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3710 return SCTP_DISPOSITION_ABORT; 3711 } 3712 3713 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3714 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3715 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3716 3717 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3718 asconf_ack)) { 3719 /* Successfully processed ASCONF_ACK. We can 3720 * release the next asconf if we have one. 3721 */ 3722 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3723 SCTP_NULL()); 3724 return SCTP_DISPOSITION_CONSUME; 3725 } 3726 3727 abort = sctp_make_abort(asoc, asconf_ack, 3728 sizeof(sctp_errhdr_t)); 3729 if (abort) { 3730 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3731 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3732 SCTP_CHUNK(abort)); 3733 } 3734 /* We are going to ABORT, so we might as well stop 3735 * processing the rest of the chunks in the packet. 3736 */ 3737 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3738 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3739 SCTP_ERROR(ECONNABORTED)); 3740 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3741 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3742 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3743 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3744 return SCTP_DISPOSITION_ABORT; 3745 } 3746 3747 return SCTP_DISPOSITION_DISCARD; 3748 } 3749 3750 /* 3751 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3752 * 3753 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3754 * its cumulative TSN point to the value carried in the FORWARD TSN 3755 * chunk, and then MUST further advance its cumulative TSN point locally 3756 * if possible. 3757 * After the above processing, the data receiver MUST stop reporting any 3758 * missing TSNs earlier than or equal to the new cumulative TSN point. 3759 * 3760 * Verification Tag: 8.5 Verification Tag [Normal verification] 3761 * 3762 * The return value is the disposition of the chunk. 3763 */ 3764 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3765 const struct sctp_association *asoc, 3766 const sctp_subtype_t type, 3767 void *arg, 3768 sctp_cmd_seq_t *commands) 3769 { 3770 struct sctp_chunk *chunk = arg; 3771 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3772 struct sctp_fwdtsn_skip *skip; 3773 __u16 len; 3774 __u32 tsn; 3775 3776 if (!sctp_vtag_verify(chunk, asoc)) { 3777 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3778 SCTP_NULL()); 3779 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3780 } 3781 3782 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3783 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3784 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3785 commands); 3786 3787 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3788 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3789 len = ntohs(chunk->chunk_hdr->length); 3790 len -= sizeof(struct sctp_chunkhdr); 3791 skb_pull(chunk->skb, len); 3792 3793 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3794 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3795 3796 /* The TSN is too high--silently discard the chunk and count on it 3797 * getting retransmitted later. 3798 */ 3799 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3800 goto discard_noforce; 3801 3802 /* Silently discard the chunk if stream-id is not valid */ 3803 sctp_walk_fwdtsn(skip, chunk) { 3804 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3805 goto discard_noforce; 3806 } 3807 3808 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3809 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3810 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3811 SCTP_CHUNK(chunk)); 3812 3813 /* Count this as receiving DATA. */ 3814 if (asoc->autoclose) { 3815 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3816 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3817 } 3818 3819 /* FIXME: For now send a SACK, but DATA processing may 3820 * send another. 3821 */ 3822 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3823 3824 return SCTP_DISPOSITION_CONSUME; 3825 3826 discard_noforce: 3827 return SCTP_DISPOSITION_DISCARD; 3828 } 3829 3830 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3831 const struct sctp_endpoint *ep, 3832 const struct sctp_association *asoc, 3833 const sctp_subtype_t type, 3834 void *arg, 3835 sctp_cmd_seq_t *commands) 3836 { 3837 struct sctp_chunk *chunk = arg; 3838 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3839 struct sctp_fwdtsn_skip *skip; 3840 __u16 len; 3841 __u32 tsn; 3842 3843 if (!sctp_vtag_verify(chunk, asoc)) { 3844 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3845 SCTP_NULL()); 3846 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3847 } 3848 3849 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3850 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3851 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3852 commands); 3853 3854 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3855 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3856 len = ntohs(chunk->chunk_hdr->length); 3857 len -= sizeof(struct sctp_chunkhdr); 3858 skb_pull(chunk->skb, len); 3859 3860 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3861 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3862 3863 /* The TSN is too high--silently discard the chunk and count on it 3864 * getting retransmitted later. 3865 */ 3866 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3867 goto gen_shutdown; 3868 3869 /* Silently discard the chunk if stream-id is not valid */ 3870 sctp_walk_fwdtsn(skip, chunk) { 3871 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3872 goto gen_shutdown; 3873 } 3874 3875 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3876 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3877 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3878 SCTP_CHUNK(chunk)); 3879 3880 /* Go a head and force a SACK, since we are shutting down. */ 3881 gen_shutdown: 3882 /* Implementor's Guide. 3883 * 3884 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3885 * respond to each received packet containing one or more DATA chunk(s) 3886 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3887 */ 3888 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3889 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3890 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3891 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3892 3893 return SCTP_DISPOSITION_CONSUME; 3894 } 3895 3896 /* 3897 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3898 * 3899 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3900 * Identifier field. If this algorithm was not specified by the 3901 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3902 * during association setup, the AUTH chunk and all chunks after it MUST 3903 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3904 * defined in Section 4.1. 3905 * 3906 * If an endpoint with no shared key receives a Shared Key Identifier 3907 * other than 0, it MUST silently discard all authenticated chunks. If 3908 * the endpoint has at least one endpoint pair shared key for the peer, 3909 * it MUST use the key specified by the Shared Key Identifier if a 3910 * key has been configured for that Shared Key Identifier. If no 3911 * endpoint pair shared key has been configured for that Shared Key 3912 * Identifier, all authenticated chunks MUST be silently discarded. 3913 * 3914 * Verification Tag: 8.5 Verification Tag [Normal verification] 3915 * 3916 * The return value is the disposition of the chunk. 3917 */ 3918 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 3919 const struct sctp_association *asoc, 3920 const sctp_subtype_t type, 3921 struct sctp_chunk *chunk) 3922 { 3923 struct sctp_authhdr *auth_hdr; 3924 struct sctp_hmac *hmac; 3925 unsigned int sig_len; 3926 __u16 key_id; 3927 __u8 *save_digest; 3928 __u8 *digest; 3929 3930 /* Pull in the auth header, so we can do some more verification */ 3931 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3932 chunk->subh.auth_hdr = auth_hdr; 3933 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3934 3935 /* Make sure that we suport the HMAC algorithm from the auth 3936 * chunk. 3937 */ 3938 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 3939 return SCTP_IERROR_AUTH_BAD_HMAC; 3940 3941 /* Make sure that the provided shared key identifier has been 3942 * configured 3943 */ 3944 key_id = ntohs(auth_hdr->shkey_id); 3945 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 3946 return SCTP_IERROR_AUTH_BAD_KEYID; 3947 3948 3949 /* Make sure that the length of the signature matches what 3950 * we expect. 3951 */ 3952 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 3953 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 3954 if (sig_len != hmac->hmac_len) 3955 return SCTP_IERROR_PROTO_VIOLATION; 3956 3957 /* Now that we've done validation checks, we can compute and 3958 * verify the hmac. The steps involved are: 3959 * 1. Save the digest from the chunk. 3960 * 2. Zero out the digest in the chunk. 3961 * 3. Compute the new digest 3962 * 4. Compare saved and new digests. 3963 */ 3964 digest = auth_hdr->hmac; 3965 skb_pull(chunk->skb, sig_len); 3966 3967 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 3968 if (!save_digest) 3969 goto nomem; 3970 3971 memset(digest, 0, sig_len); 3972 3973 sctp_auth_calculate_hmac(asoc, chunk->skb, 3974 (struct sctp_auth_chunk *)chunk->chunk_hdr, 3975 GFP_ATOMIC); 3976 3977 /* Discard the packet if the digests do not match */ 3978 if (memcmp(save_digest, digest, sig_len)) { 3979 kfree(save_digest); 3980 return SCTP_IERROR_BAD_SIG; 3981 } 3982 3983 kfree(save_digest); 3984 chunk->auth = 1; 3985 3986 return SCTP_IERROR_NO_ERROR; 3987 nomem: 3988 return SCTP_IERROR_NOMEM; 3989 } 3990 3991 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep, 3992 const struct sctp_association *asoc, 3993 const sctp_subtype_t type, 3994 void *arg, 3995 sctp_cmd_seq_t *commands) 3996 { 3997 struct sctp_authhdr *auth_hdr; 3998 struct sctp_chunk *chunk = arg; 3999 struct sctp_chunk *err_chunk; 4000 sctp_ierror_t error; 4001 4002 /* Make sure that the peer has AUTH capable */ 4003 if (!asoc->peer.auth_capable) 4004 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands); 4005 4006 if (!sctp_vtag_verify(chunk, asoc)) { 4007 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4008 SCTP_NULL()); 4009 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4010 } 4011 4012 /* Make sure that the AUTH chunk has valid length. */ 4013 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4014 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4015 commands); 4016 4017 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4018 error = sctp_sf_authenticate(ep, asoc, type, chunk); 4019 switch (error) { 4020 case SCTP_IERROR_AUTH_BAD_HMAC: 4021 /* Generate the ERROR chunk and discard the rest 4022 * of the packet 4023 */ 4024 err_chunk = sctp_make_op_error(asoc, chunk, 4025 SCTP_ERROR_UNSUP_HMAC, 4026 &auth_hdr->hmac_id, 4027 sizeof(__u16), 0); 4028 if (err_chunk) { 4029 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4030 SCTP_CHUNK(err_chunk)); 4031 } 4032 /* Fall Through */ 4033 case SCTP_IERROR_AUTH_BAD_KEYID: 4034 case SCTP_IERROR_BAD_SIG: 4035 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4036 4037 case SCTP_IERROR_PROTO_VIOLATION: 4038 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4039 commands); 4040 4041 case SCTP_IERROR_NOMEM: 4042 return SCTP_DISPOSITION_NOMEM; 4043 4044 default: /* Prevent gcc warnings */ 4045 break; 4046 } 4047 4048 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4049 struct sctp_ulpevent *ev; 4050 4051 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4052 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4053 4054 if (!ev) 4055 return -ENOMEM; 4056 4057 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4058 SCTP_ULPEVENT(ev)); 4059 } 4060 4061 return SCTP_DISPOSITION_CONSUME; 4062 } 4063 4064 /* 4065 * Process an unknown chunk. 4066 * 4067 * Section: 3.2. Also, 2.1 in the implementor's guide. 4068 * 4069 * Chunk Types are encoded such that the highest-order two bits specify 4070 * the action that must be taken if the processing endpoint does not 4071 * recognize the Chunk Type. 4072 * 4073 * 00 - Stop processing this SCTP packet and discard it, do not process 4074 * any further chunks within it. 4075 * 4076 * 01 - Stop processing this SCTP packet and discard it, do not process 4077 * any further chunks within it, and report the unrecognized 4078 * chunk in an 'Unrecognized Chunk Type'. 4079 * 4080 * 10 - Skip this chunk and continue processing. 4081 * 4082 * 11 - Skip this chunk and continue processing, but report in an ERROR 4083 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4084 * 4085 * The return value is the disposition of the chunk. 4086 */ 4087 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 4088 const struct sctp_association *asoc, 4089 const sctp_subtype_t type, 4090 void *arg, 4091 sctp_cmd_seq_t *commands) 4092 { 4093 struct sctp_chunk *unk_chunk = arg; 4094 struct sctp_chunk *err_chunk; 4095 sctp_chunkhdr_t *hdr; 4096 4097 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 4098 4099 if (!sctp_vtag_verify(unk_chunk, asoc)) 4100 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4101 4102 /* Make sure that the chunk has a valid length. 4103 * Since we don't know the chunk type, we use a general 4104 * chunkhdr structure to make a comparison. 4105 */ 4106 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4107 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4108 commands); 4109 4110 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4111 case SCTP_CID_ACTION_DISCARD: 4112 /* Discard the packet. */ 4113 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4114 break; 4115 case SCTP_CID_ACTION_DISCARD_ERR: 4116 /* Generate an ERROR chunk as response. */ 4117 hdr = unk_chunk->chunk_hdr; 4118 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4119 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4120 WORD_ROUND(ntohs(hdr->length)), 4121 0); 4122 if (err_chunk) { 4123 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4124 SCTP_CHUNK(err_chunk)); 4125 } 4126 4127 /* Discard the packet. */ 4128 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4129 return SCTP_DISPOSITION_CONSUME; 4130 break; 4131 case SCTP_CID_ACTION_SKIP: 4132 /* Skip the chunk. */ 4133 return SCTP_DISPOSITION_DISCARD; 4134 break; 4135 case SCTP_CID_ACTION_SKIP_ERR: 4136 /* Generate an ERROR chunk as response. */ 4137 hdr = unk_chunk->chunk_hdr; 4138 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4139 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4140 WORD_ROUND(ntohs(hdr->length)), 4141 0); 4142 if (err_chunk) { 4143 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4144 SCTP_CHUNK(err_chunk)); 4145 } 4146 /* Skip the chunk. */ 4147 return SCTP_DISPOSITION_CONSUME; 4148 break; 4149 default: 4150 break; 4151 } 4152 4153 return SCTP_DISPOSITION_DISCARD; 4154 } 4155 4156 /* 4157 * Discard the chunk. 4158 * 4159 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4160 * [Too numerous to mention...] 4161 * Verification Tag: No verification needed. 4162 * Inputs 4163 * (endpoint, asoc, chunk) 4164 * 4165 * Outputs 4166 * (asoc, reply_msg, msg_up, timers, counters) 4167 * 4168 * The return value is the disposition of the chunk. 4169 */ 4170 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 4171 const struct sctp_association *asoc, 4172 const sctp_subtype_t type, 4173 void *arg, 4174 sctp_cmd_seq_t *commands) 4175 { 4176 struct sctp_chunk *chunk = arg; 4177 4178 /* Make sure that the chunk has a valid length. 4179 * Since we don't know the chunk type, we use a general 4180 * chunkhdr structure to make a comparison. 4181 */ 4182 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4183 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4184 commands); 4185 4186 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 4187 return SCTP_DISPOSITION_DISCARD; 4188 } 4189 4190 /* 4191 * Discard the whole packet. 4192 * 4193 * Section: 8.4 2) 4194 * 4195 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4196 * silently discard the OOTB packet and take no further action. 4197 * 4198 * Verification Tag: No verification necessary 4199 * 4200 * Inputs 4201 * (endpoint, asoc, chunk) 4202 * 4203 * Outputs 4204 * (asoc, reply_msg, msg_up, timers, counters) 4205 * 4206 * The return value is the disposition of the chunk. 4207 */ 4208 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 4209 const struct sctp_association *asoc, 4210 const sctp_subtype_t type, 4211 void *arg, 4212 sctp_cmd_seq_t *commands) 4213 { 4214 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS); 4215 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4216 4217 return SCTP_DISPOSITION_CONSUME; 4218 } 4219 4220 4221 /* 4222 * The other end is violating protocol. 4223 * 4224 * Section: Not specified 4225 * Verification Tag: Not specified 4226 * Inputs 4227 * (endpoint, asoc, chunk) 4228 * 4229 * Outputs 4230 * (asoc, reply_msg, msg_up, timers, counters) 4231 * 4232 * We simply tag the chunk as a violation. The state machine will log 4233 * the violation and continue. 4234 */ 4235 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 4236 const struct sctp_association *asoc, 4237 const sctp_subtype_t type, 4238 void *arg, 4239 sctp_cmd_seq_t *commands) 4240 { 4241 struct sctp_chunk *chunk = arg; 4242 4243 /* Make sure that the chunk has a valid length. */ 4244 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4245 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4246 commands); 4247 4248 return SCTP_DISPOSITION_VIOLATION; 4249 } 4250 4251 /* 4252 * Common function to handle a protocol violation. 4253 */ 4254 static sctp_disposition_t sctp_sf_abort_violation( 4255 const struct sctp_endpoint *ep, 4256 const struct sctp_association *asoc, 4257 void *arg, 4258 sctp_cmd_seq_t *commands, 4259 const __u8 *payload, 4260 const size_t paylen) 4261 { 4262 struct sctp_packet *packet = NULL; 4263 struct sctp_chunk *chunk = arg; 4264 struct sctp_chunk *abort = NULL; 4265 4266 /* SCTP-AUTH, Section 6.3: 4267 * It should be noted that if the receiver wants to tear 4268 * down an association in an authenticated way only, the 4269 * handling of malformed packets should not result in 4270 * tearing down the association. 4271 * 4272 * This means that if we only want to abort associations 4273 * in an authenticated way (i.e AUTH+ABORT), then we 4274 * can't destroy this association just because the packet 4275 * was malformed. 4276 */ 4277 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4278 goto discard; 4279 4280 /* Make the abort chunk. */ 4281 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4282 if (!abort) 4283 goto nomem; 4284 4285 if (asoc) { 4286 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4287 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4288 !asoc->peer.i.init_tag) { 4289 sctp_initack_chunk_t *initack; 4290 4291 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4292 if (!sctp_chunk_length_valid(chunk, 4293 sizeof(sctp_initack_chunk_t))) 4294 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4295 else { 4296 unsigned int inittag; 4297 4298 inittag = ntohl(initack->init_hdr.init_tag); 4299 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4300 SCTP_U32(inittag)); 4301 } 4302 } 4303 4304 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4305 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4306 4307 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4308 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4309 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4310 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4311 SCTP_ERROR(ECONNREFUSED)); 4312 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4313 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4314 } else { 4315 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4316 SCTP_ERROR(ECONNABORTED)); 4317 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4318 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4319 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4320 } 4321 } else { 4322 packet = sctp_ootb_pkt_new(asoc, chunk); 4323 4324 if (!packet) 4325 goto nomem_pkt; 4326 4327 if (sctp_test_T_bit(abort)) 4328 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4329 4330 abort->skb->sk = ep->base.sk; 4331 4332 sctp_packet_append_chunk(packet, abort); 4333 4334 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4335 SCTP_PACKET(packet)); 4336 4337 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4338 } 4339 4340 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4341 4342 discard: 4343 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4344 return SCTP_DISPOSITION_ABORT; 4345 4346 nomem_pkt: 4347 sctp_chunk_free(abort); 4348 nomem: 4349 return SCTP_DISPOSITION_NOMEM; 4350 } 4351 4352 /* 4353 * Handle a protocol violation when the chunk length is invalid. 4354 * "Invalid" length is identified as smaller than the minimal length a 4355 * given chunk can be. For example, a SACK chunk has invalid length 4356 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4357 * 4358 * We inform the other end by sending an ABORT with a Protocol Violation 4359 * error code. 4360 * 4361 * Section: Not specified 4362 * Verification Tag: Nothing to do 4363 * Inputs 4364 * (endpoint, asoc, chunk) 4365 * 4366 * Outputs 4367 * (reply_msg, msg_up, counters) 4368 * 4369 * Generate an ABORT chunk and terminate the association. 4370 */ 4371 static sctp_disposition_t sctp_sf_violation_chunklen( 4372 const struct sctp_endpoint *ep, 4373 const struct sctp_association *asoc, 4374 const sctp_subtype_t type, 4375 void *arg, 4376 sctp_cmd_seq_t *commands) 4377 { 4378 static const char err_str[]="The following chunk had invalid length:"; 4379 4380 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4381 sizeof(err_str)); 4382 } 4383 4384 /* 4385 * Handle a protocol violation when the parameter length is invalid. 4386 * If the length is smaller than the minimum length of a given parameter, 4387 * or accumulated length in multi parameters exceeds the end of the chunk, 4388 * the length is considered as invalid. 4389 */ 4390 static sctp_disposition_t sctp_sf_violation_paramlen( 4391 const struct sctp_endpoint *ep, 4392 const struct sctp_association *asoc, 4393 const sctp_subtype_t type, 4394 void *arg, void *ext, 4395 sctp_cmd_seq_t *commands) 4396 { 4397 struct sctp_chunk *chunk = arg; 4398 struct sctp_paramhdr *param = ext; 4399 struct sctp_chunk *abort = NULL; 4400 4401 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4402 goto discard; 4403 4404 /* Make the abort chunk. */ 4405 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4406 if (!abort) 4407 goto nomem; 4408 4409 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4410 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4411 4412 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4413 SCTP_ERROR(ECONNABORTED)); 4414 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4415 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4416 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4417 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4418 4419 discard: 4420 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4421 return SCTP_DISPOSITION_ABORT; 4422 nomem: 4423 return SCTP_DISPOSITION_NOMEM; 4424 } 4425 4426 /* Handle a protocol violation when the peer trying to advance the 4427 * cumulative tsn ack to a point beyond the max tsn currently sent. 4428 * 4429 * We inform the other end by sending an ABORT with a Protocol Violation 4430 * error code. 4431 */ 4432 static sctp_disposition_t sctp_sf_violation_ctsn( 4433 const struct sctp_endpoint *ep, 4434 const struct sctp_association *asoc, 4435 const sctp_subtype_t type, 4436 void *arg, 4437 sctp_cmd_seq_t *commands) 4438 { 4439 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4440 4441 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4442 sizeof(err_str)); 4443 } 4444 4445 /* Handle protocol violation of an invalid chunk bundling. For example, 4446 * when we have an association and we receive bundled INIT-ACK, or 4447 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4448 * statement from the specs. Additionally, there might be an attacker 4449 * on the path and we may not want to continue this communication. 4450 */ 4451 static sctp_disposition_t sctp_sf_violation_chunk( 4452 const struct sctp_endpoint *ep, 4453 const struct sctp_association *asoc, 4454 const sctp_subtype_t type, 4455 void *arg, 4456 sctp_cmd_seq_t *commands) 4457 { 4458 static const char err_str[]="The following chunk violates protocol:"; 4459 4460 if (!asoc) 4461 return sctp_sf_violation(ep, asoc, type, arg, commands); 4462 4463 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4464 sizeof(err_str)); 4465 } 4466 /*************************************************************************** 4467 * These are the state functions for handling primitive (Section 10) events. 4468 ***************************************************************************/ 4469 /* 4470 * sctp_sf_do_prm_asoc 4471 * 4472 * Section: 10.1 ULP-to-SCTP 4473 * B) Associate 4474 * 4475 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4476 * outbound stream count) 4477 * -> association id [,destination transport addr list] [,outbound stream 4478 * count] 4479 * 4480 * This primitive allows the upper layer to initiate an association to a 4481 * specific peer endpoint. 4482 * 4483 * The peer endpoint shall be specified by one of the transport addresses 4484 * which defines the endpoint (see Section 1.4). If the local SCTP 4485 * instance has not been initialized, the ASSOCIATE is considered an 4486 * error. 4487 * [This is not relevant for the kernel implementation since we do all 4488 * initialization at boot time. It we hadn't initialized we wouldn't 4489 * get anywhere near this code.] 4490 * 4491 * An association id, which is a local handle to the SCTP association, 4492 * will be returned on successful establishment of the association. If 4493 * SCTP is not able to open an SCTP association with the peer endpoint, 4494 * an error is returned. 4495 * [In the kernel implementation, the struct sctp_association needs to 4496 * be created BEFORE causing this primitive to run.] 4497 * 4498 * Other association parameters may be returned, including the 4499 * complete destination transport addresses of the peer as well as the 4500 * outbound stream count of the local endpoint. One of the transport 4501 * address from the returned destination addresses will be selected by 4502 * the local endpoint as default primary path for sending SCTP packets 4503 * to this peer. The returned "destination transport addr list" can 4504 * be used by the ULP to change the default primary path or to force 4505 * sending a packet to a specific transport address. [All of this 4506 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4507 * function.] 4508 * 4509 * Mandatory attributes: 4510 * 4511 * o local SCTP instance name - obtained from the INITIALIZE operation. 4512 * [This is the argument asoc.] 4513 * o destination transport addr - specified as one of the transport 4514 * addresses of the peer endpoint with which the association is to be 4515 * established. 4516 * [This is asoc->peer.active_path.] 4517 * o outbound stream count - the number of outbound streams the ULP 4518 * would like to open towards this peer endpoint. 4519 * [BUG: This is not currently implemented.] 4520 * Optional attributes: 4521 * 4522 * None. 4523 * 4524 * The return value is a disposition. 4525 */ 4526 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 4527 const struct sctp_association *asoc, 4528 const sctp_subtype_t type, 4529 void *arg, 4530 sctp_cmd_seq_t *commands) 4531 { 4532 struct sctp_chunk *repl; 4533 struct sctp_association* my_asoc; 4534 4535 /* The comment below says that we enter COOKIE-WAIT AFTER 4536 * sending the INIT, but that doesn't actually work in our 4537 * implementation... 4538 */ 4539 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4540 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4541 4542 /* RFC 2960 5.1 Normal Establishment of an Association 4543 * 4544 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4545 * must provide its Verification Tag (Tag_A) in the Initiate 4546 * Tag field. Tag_A SHOULD be a random number in the range of 4547 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4548 */ 4549 4550 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4551 if (!repl) 4552 goto nomem; 4553 4554 /* Cast away the const modifier, as we want to just 4555 * rerun it through as a sideffect. 4556 */ 4557 my_asoc = (struct sctp_association *)asoc; 4558 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4559 4560 /* Choose transport for INIT. */ 4561 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4562 SCTP_CHUNK(repl)); 4563 4564 /* After sending the INIT, "A" starts the T1-init timer and 4565 * enters the COOKIE-WAIT state. 4566 */ 4567 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4568 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4569 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4570 return SCTP_DISPOSITION_CONSUME; 4571 4572 nomem: 4573 return SCTP_DISPOSITION_NOMEM; 4574 } 4575 4576 /* 4577 * Process the SEND primitive. 4578 * 4579 * Section: 10.1 ULP-to-SCTP 4580 * E) Send 4581 * 4582 * Format: SEND(association id, buffer address, byte count [,context] 4583 * [,stream id] [,life time] [,destination transport address] 4584 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4585 * -> result 4586 * 4587 * This is the main method to send user data via SCTP. 4588 * 4589 * Mandatory attributes: 4590 * 4591 * o association id - local handle to the SCTP association 4592 * 4593 * o buffer address - the location where the user message to be 4594 * transmitted is stored; 4595 * 4596 * o byte count - The size of the user data in number of bytes; 4597 * 4598 * Optional attributes: 4599 * 4600 * o context - an optional 32 bit integer that will be carried in the 4601 * sending failure notification to the ULP if the transportation of 4602 * this User Message fails. 4603 * 4604 * o stream id - to indicate which stream to send the data on. If not 4605 * specified, stream 0 will be used. 4606 * 4607 * o life time - specifies the life time of the user data. The user data 4608 * will not be sent by SCTP after the life time expires. This 4609 * parameter can be used to avoid efforts to transmit stale 4610 * user messages. SCTP notifies the ULP if the data cannot be 4611 * initiated to transport (i.e. sent to the destination via SCTP's 4612 * send primitive) within the life time variable. However, the 4613 * user data will be transmitted if SCTP has attempted to transmit a 4614 * chunk before the life time expired. 4615 * 4616 * o destination transport address - specified as one of the destination 4617 * transport addresses of the peer endpoint to which this packet 4618 * should be sent. Whenever possible, SCTP should use this destination 4619 * transport address for sending the packets, instead of the current 4620 * primary path. 4621 * 4622 * o unorder flag - this flag, if present, indicates that the user 4623 * would like the data delivered in an unordered fashion to the peer 4624 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4625 * message). 4626 * 4627 * o no-bundle flag - instructs SCTP not to bundle this user data with 4628 * other outbound DATA chunks. SCTP MAY still bundle even when 4629 * this flag is present, when faced with network congestion. 4630 * 4631 * o payload protocol-id - A 32 bit unsigned integer that is to be 4632 * passed to the peer indicating the type of payload protocol data 4633 * being transmitted. This value is passed as opaque data by SCTP. 4634 * 4635 * The return value is the disposition. 4636 */ 4637 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 4638 const struct sctp_association *asoc, 4639 const sctp_subtype_t type, 4640 void *arg, 4641 sctp_cmd_seq_t *commands) 4642 { 4643 struct sctp_datamsg *msg = arg; 4644 4645 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4646 return SCTP_DISPOSITION_CONSUME; 4647 } 4648 4649 /* 4650 * Process the SHUTDOWN primitive. 4651 * 4652 * Section: 10.1: 4653 * C) Shutdown 4654 * 4655 * Format: SHUTDOWN(association id) 4656 * -> result 4657 * 4658 * Gracefully closes an association. Any locally queued user data 4659 * will be delivered to the peer. The association will be terminated only 4660 * after the peer acknowledges all the SCTP packets sent. A success code 4661 * will be returned on successful termination of the association. If 4662 * attempting to terminate the association results in a failure, an error 4663 * code shall be returned. 4664 * 4665 * Mandatory attributes: 4666 * 4667 * o association id - local handle to the SCTP association 4668 * 4669 * Optional attributes: 4670 * 4671 * None. 4672 * 4673 * The return value is the disposition. 4674 */ 4675 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4676 const struct sctp_endpoint *ep, 4677 const struct sctp_association *asoc, 4678 const sctp_subtype_t type, 4679 void *arg, 4680 sctp_cmd_seq_t *commands) 4681 { 4682 int disposition; 4683 4684 /* From 9.2 Shutdown of an Association 4685 * Upon receipt of the SHUTDOWN primitive from its upper 4686 * layer, the endpoint enters SHUTDOWN-PENDING state and 4687 * remains there until all outstanding data has been 4688 * acknowledged by its peer. The endpoint accepts no new data 4689 * from its upper layer, but retransmits data to the far end 4690 * if necessary to fill gaps. 4691 */ 4692 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4693 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4694 4695 disposition = SCTP_DISPOSITION_CONSUME; 4696 if (sctp_outq_is_empty(&asoc->outqueue)) { 4697 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4698 arg, commands); 4699 } 4700 return disposition; 4701 } 4702 4703 /* 4704 * Process the ABORT primitive. 4705 * 4706 * Section: 10.1: 4707 * C) Abort 4708 * 4709 * Format: Abort(association id [, cause code]) 4710 * -> result 4711 * 4712 * Ungracefully closes an association. Any locally queued user data 4713 * will be discarded and an ABORT chunk is sent to the peer. A success code 4714 * will be returned on successful abortion of the association. If 4715 * attempting to abort the association results in a failure, an error 4716 * code shall be returned. 4717 * 4718 * Mandatory attributes: 4719 * 4720 * o association id - local handle to the SCTP association 4721 * 4722 * Optional attributes: 4723 * 4724 * o cause code - reason of the abort to be passed to the peer 4725 * 4726 * None. 4727 * 4728 * The return value is the disposition. 4729 */ 4730 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4731 const struct sctp_endpoint *ep, 4732 const struct sctp_association *asoc, 4733 const sctp_subtype_t type, 4734 void *arg, 4735 sctp_cmd_seq_t *commands) 4736 { 4737 /* From 9.1 Abort of an Association 4738 * Upon receipt of the ABORT primitive from its upper 4739 * layer, the endpoint enters CLOSED state and 4740 * discard all outstanding data has been 4741 * acknowledged by its peer. The endpoint accepts no new data 4742 * from its upper layer, but retransmits data to the far end 4743 * if necessary to fill gaps. 4744 */ 4745 struct sctp_chunk *abort = arg; 4746 sctp_disposition_t retval; 4747 4748 retval = SCTP_DISPOSITION_CONSUME; 4749 4750 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4751 4752 /* Even if we can't send the ABORT due to low memory delete the 4753 * TCB. This is a departure from our typical NOMEM handling. 4754 */ 4755 4756 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4757 SCTP_ERROR(ECONNABORTED)); 4758 /* Delete the established association. */ 4759 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4760 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4761 4762 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4763 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4764 4765 return retval; 4766 } 4767 4768 /* We tried an illegal operation on an association which is closed. */ 4769 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4770 const struct sctp_association *asoc, 4771 const sctp_subtype_t type, 4772 void *arg, 4773 sctp_cmd_seq_t *commands) 4774 { 4775 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4776 return SCTP_DISPOSITION_CONSUME; 4777 } 4778 4779 /* We tried an illegal operation on an association which is shutting 4780 * down. 4781 */ 4782 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4783 const struct sctp_association *asoc, 4784 const sctp_subtype_t type, 4785 void *arg, 4786 sctp_cmd_seq_t *commands) 4787 { 4788 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4789 SCTP_ERROR(-ESHUTDOWN)); 4790 return SCTP_DISPOSITION_CONSUME; 4791 } 4792 4793 /* 4794 * sctp_cookie_wait_prm_shutdown 4795 * 4796 * Section: 4 Note: 2 4797 * Verification Tag: 4798 * Inputs 4799 * (endpoint, asoc) 4800 * 4801 * The RFC does not explicitly address this issue, but is the route through the 4802 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4803 * 4804 * Outputs 4805 * (timers) 4806 */ 4807 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4808 const struct sctp_endpoint *ep, 4809 const struct sctp_association *asoc, 4810 const sctp_subtype_t type, 4811 void *arg, 4812 sctp_cmd_seq_t *commands) 4813 { 4814 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4815 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4816 4817 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4818 SCTP_STATE(SCTP_STATE_CLOSED)); 4819 4820 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4821 4822 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4823 4824 return SCTP_DISPOSITION_DELETE_TCB; 4825 } 4826 4827 /* 4828 * sctp_cookie_echoed_prm_shutdown 4829 * 4830 * Section: 4 Note: 2 4831 * Verification Tag: 4832 * Inputs 4833 * (endpoint, asoc) 4834 * 4835 * The RFC does not explcitly address this issue, but is the route through the 4836 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4837 * 4838 * Outputs 4839 * (timers) 4840 */ 4841 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4842 const struct sctp_endpoint *ep, 4843 const struct sctp_association *asoc, 4844 const sctp_subtype_t type, 4845 void *arg, sctp_cmd_seq_t *commands) 4846 { 4847 /* There is a single T1 timer, so we should be able to use 4848 * common function with the COOKIE-WAIT state. 4849 */ 4850 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4851 } 4852 4853 /* 4854 * sctp_sf_cookie_wait_prm_abort 4855 * 4856 * Section: 4 Note: 2 4857 * Verification Tag: 4858 * Inputs 4859 * (endpoint, asoc) 4860 * 4861 * The RFC does not explicitly address this issue, but is the route through the 4862 * state table when someone issues an abort while in COOKIE_WAIT state. 4863 * 4864 * Outputs 4865 * (timers) 4866 */ 4867 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4868 const struct sctp_endpoint *ep, 4869 const struct sctp_association *asoc, 4870 const sctp_subtype_t type, 4871 void *arg, 4872 sctp_cmd_seq_t *commands) 4873 { 4874 struct sctp_chunk *abort = arg; 4875 sctp_disposition_t retval; 4876 4877 /* Stop T1-init timer */ 4878 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4879 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4880 retval = SCTP_DISPOSITION_CONSUME; 4881 4882 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4883 4884 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4885 SCTP_STATE(SCTP_STATE_CLOSED)); 4886 4887 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4888 4889 /* Even if we can't send the ABORT due to low memory delete the 4890 * TCB. This is a departure from our typical NOMEM handling. 4891 */ 4892 4893 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4894 SCTP_ERROR(ECONNREFUSED)); 4895 /* Delete the established association. */ 4896 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4897 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4898 4899 return retval; 4900 } 4901 4902 /* 4903 * sctp_sf_cookie_echoed_prm_abort 4904 * 4905 * Section: 4 Note: 3 4906 * Verification Tag: 4907 * Inputs 4908 * (endpoint, asoc) 4909 * 4910 * The RFC does not explcitly address this issue, but is the route through the 4911 * state table when someone issues an abort while in COOKIE_ECHOED state. 4912 * 4913 * Outputs 4914 * (timers) 4915 */ 4916 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4917 const struct sctp_endpoint *ep, 4918 const struct sctp_association *asoc, 4919 const sctp_subtype_t type, 4920 void *arg, 4921 sctp_cmd_seq_t *commands) 4922 { 4923 /* There is a single T1 timer, so we should be able to use 4924 * common function with the COOKIE-WAIT state. 4925 */ 4926 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4927 } 4928 4929 /* 4930 * sctp_sf_shutdown_pending_prm_abort 4931 * 4932 * Inputs 4933 * (endpoint, asoc) 4934 * 4935 * The RFC does not explicitly address this issue, but is the route through the 4936 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4937 * 4938 * Outputs 4939 * (timers) 4940 */ 4941 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4942 const struct sctp_endpoint *ep, 4943 const struct sctp_association *asoc, 4944 const sctp_subtype_t type, 4945 void *arg, 4946 sctp_cmd_seq_t *commands) 4947 { 4948 /* Stop the T5-shutdown guard timer. */ 4949 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4950 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4951 4952 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4953 } 4954 4955 /* 4956 * sctp_sf_shutdown_sent_prm_abort 4957 * 4958 * Inputs 4959 * (endpoint, asoc) 4960 * 4961 * The RFC does not explicitly address this issue, but is the route through the 4962 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4963 * 4964 * Outputs 4965 * (timers) 4966 */ 4967 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4968 const struct sctp_endpoint *ep, 4969 const struct sctp_association *asoc, 4970 const sctp_subtype_t type, 4971 void *arg, 4972 sctp_cmd_seq_t *commands) 4973 { 4974 /* Stop the T2-shutdown timer. */ 4975 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4976 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4977 4978 /* Stop the T5-shutdown guard timer. */ 4979 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4980 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4981 4982 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4983 } 4984 4985 /* 4986 * sctp_sf_cookie_echoed_prm_abort 4987 * 4988 * Inputs 4989 * (endpoint, asoc) 4990 * 4991 * The RFC does not explcitly address this issue, but is the route through the 4992 * state table when someone issues an abort while in COOKIE_ECHOED state. 4993 * 4994 * Outputs 4995 * (timers) 4996 */ 4997 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4998 const struct sctp_endpoint *ep, 4999 const struct sctp_association *asoc, 5000 const sctp_subtype_t type, 5001 void *arg, 5002 sctp_cmd_seq_t *commands) 5003 { 5004 /* The same T2 timer, so we should be able to use 5005 * common function with the SHUTDOWN-SENT state. 5006 */ 5007 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 5008 } 5009 5010 /* 5011 * Process the REQUESTHEARTBEAT primitive 5012 * 5013 * 10.1 ULP-to-SCTP 5014 * J) Request Heartbeat 5015 * 5016 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5017 * 5018 * -> result 5019 * 5020 * Instructs the local endpoint to perform a HeartBeat on the specified 5021 * destination transport address of the given association. The returned 5022 * result should indicate whether the transmission of the HEARTBEAT 5023 * chunk to the destination address is successful. 5024 * 5025 * Mandatory attributes: 5026 * 5027 * o association id - local handle to the SCTP association 5028 * 5029 * o destination transport address - the transport address of the 5030 * association on which a heartbeat should be issued. 5031 */ 5032 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5033 const struct sctp_endpoint *ep, 5034 const struct sctp_association *asoc, 5035 const sctp_subtype_t type, 5036 void *arg, 5037 sctp_cmd_seq_t *commands) 5038 { 5039 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5040 (struct sctp_transport *)arg, commands)) 5041 return SCTP_DISPOSITION_NOMEM; 5042 5043 /* 5044 * RFC 2960 (bis), section 8.3 5045 * 5046 * D) Request an on-demand HEARTBEAT on a specific destination 5047 * transport address of a given association. 5048 * 5049 * The endpoint should increment the respective error counter of 5050 * the destination transport address each time a HEARTBEAT is sent 5051 * to that address and not acknowledged within one RTO. 5052 * 5053 */ 5054 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5055 SCTP_TRANSPORT(arg)); 5056 return SCTP_DISPOSITION_CONSUME; 5057 } 5058 5059 /* 5060 * ADDIP Section 4.1 ASCONF Chunk Procedures 5061 * When an endpoint has an ASCONF signaled change to be sent to the 5062 * remote endpoint it should do A1 to A9 5063 */ 5064 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 5065 const struct sctp_association *asoc, 5066 const sctp_subtype_t type, 5067 void *arg, 5068 sctp_cmd_seq_t *commands) 5069 { 5070 struct sctp_chunk *chunk = arg; 5071 5072 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5073 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5074 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5075 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5076 return SCTP_DISPOSITION_CONSUME; 5077 } 5078 5079 /* 5080 * Ignore the primitive event 5081 * 5082 * The return value is the disposition of the primitive. 5083 */ 5084 sctp_disposition_t sctp_sf_ignore_primitive( 5085 const struct sctp_endpoint *ep, 5086 const struct sctp_association *asoc, 5087 const sctp_subtype_t type, 5088 void *arg, 5089 sctp_cmd_seq_t *commands) 5090 { 5091 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 5092 return SCTP_DISPOSITION_DISCARD; 5093 } 5094 5095 /*************************************************************************** 5096 * These are the state functions for the OTHER events. 5097 ***************************************************************************/ 5098 5099 /* 5100 * When the SCTP stack has no more user data to send or retransmit, this 5101 * notification is given to the user. Also, at the time when a user app 5102 * subscribes to this event, if there is no data to be sent or 5103 * retransmit, the stack will immediately send up this notification. 5104 */ 5105 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5106 const struct sctp_endpoint *ep, 5107 const struct sctp_association *asoc, 5108 const sctp_subtype_t type, 5109 void *arg, 5110 sctp_cmd_seq_t *commands) 5111 { 5112 struct sctp_ulpevent *event; 5113 5114 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5115 if (!event) 5116 return SCTP_DISPOSITION_NOMEM; 5117 5118 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5119 5120 return SCTP_DISPOSITION_CONSUME; 5121 } 5122 5123 /* 5124 * Start the shutdown negotiation. 5125 * 5126 * From Section 9.2: 5127 * Once all its outstanding data has been acknowledged, the endpoint 5128 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5129 * TSN Ack field the last sequential TSN it has received from the peer. 5130 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5131 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5132 * with the updated last sequential TSN received from its peer. 5133 * 5134 * The return value is the disposition. 5135 */ 5136 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5137 const struct sctp_endpoint *ep, 5138 const struct sctp_association *asoc, 5139 const sctp_subtype_t type, 5140 void *arg, 5141 sctp_cmd_seq_t *commands) 5142 { 5143 struct sctp_chunk *reply; 5144 5145 /* Once all its outstanding data has been acknowledged, the 5146 * endpoint shall send a SHUTDOWN chunk to its peer including 5147 * in the Cumulative TSN Ack field the last sequential TSN it 5148 * has received from the peer. 5149 */ 5150 reply = sctp_make_shutdown(asoc, NULL); 5151 if (!reply) 5152 goto nomem; 5153 5154 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5155 * T2-shutdown timer. 5156 */ 5157 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5158 5159 /* It shall then start the T2-shutdown timer */ 5160 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5161 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5162 5163 /* RFC 4960 Section 9.2 5164 * The sender of the SHUTDOWN MAY also start an overall guard timer 5165 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5166 */ 5167 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5168 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5169 5170 if (asoc->autoclose) 5171 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5172 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5173 5174 /* and enter the SHUTDOWN-SENT state. */ 5175 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5176 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5177 5178 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5179 * 5180 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5181 * or SHUTDOWN-ACK. 5182 */ 5183 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5184 5185 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5186 5187 return SCTP_DISPOSITION_CONSUME; 5188 5189 nomem: 5190 return SCTP_DISPOSITION_NOMEM; 5191 } 5192 5193 /* 5194 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5195 * 5196 * From Section 9.2: 5197 * 5198 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5199 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5200 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5201 * endpoint must re-send the SHUTDOWN ACK. 5202 * 5203 * The return value is the disposition. 5204 */ 5205 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5206 const struct sctp_endpoint *ep, 5207 const struct sctp_association *asoc, 5208 const sctp_subtype_t type, 5209 void *arg, 5210 sctp_cmd_seq_t *commands) 5211 { 5212 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5213 struct sctp_chunk *reply; 5214 5215 /* There are 2 ways of getting here: 5216 * 1) called in response to a SHUTDOWN chunk 5217 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5218 * 5219 * For the case (2), the arg parameter is set to NULL. We need 5220 * to check that we have a chunk before accessing it's fields. 5221 */ 5222 if (chunk) { 5223 if (!sctp_vtag_verify(chunk, asoc)) 5224 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 5225 5226 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5227 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5228 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 5229 commands); 5230 } 5231 5232 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5233 * shall send a SHUTDOWN ACK ... 5234 */ 5235 reply = sctp_make_shutdown_ack(asoc, chunk); 5236 if (!reply) 5237 goto nomem; 5238 5239 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5240 * the T2-shutdown timer. 5241 */ 5242 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5243 5244 /* and start/restart a T2-shutdown timer of its own, */ 5245 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5246 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5247 5248 if (asoc->autoclose) 5249 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5250 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5251 5252 /* Enter the SHUTDOWN-ACK-SENT state. */ 5253 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5254 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5255 5256 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5257 * 5258 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5259 * or SHUTDOWN-ACK. 5260 */ 5261 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5262 5263 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5264 5265 return SCTP_DISPOSITION_CONSUME; 5266 5267 nomem: 5268 return SCTP_DISPOSITION_NOMEM; 5269 } 5270 5271 /* 5272 * Ignore the event defined as other 5273 * 5274 * The return value is the disposition of the event. 5275 */ 5276 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 5277 const struct sctp_association *asoc, 5278 const sctp_subtype_t type, 5279 void *arg, 5280 sctp_cmd_seq_t *commands) 5281 { 5282 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5283 return SCTP_DISPOSITION_DISCARD; 5284 } 5285 5286 /************************************************************ 5287 * These are the state functions for handling timeout events. 5288 ************************************************************/ 5289 5290 /* 5291 * RTX Timeout 5292 * 5293 * Section: 6.3.3 Handle T3-rtx Expiration 5294 * 5295 * Whenever the retransmission timer T3-rtx expires for a destination 5296 * address, do the following: 5297 * [See below] 5298 * 5299 * The return value is the disposition of the chunk. 5300 */ 5301 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 5302 const struct sctp_association *asoc, 5303 const sctp_subtype_t type, 5304 void *arg, 5305 sctp_cmd_seq_t *commands) 5306 { 5307 struct sctp_transport *transport = arg; 5308 5309 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS); 5310 5311 if (asoc->overall_error_count >= asoc->max_retrans) { 5312 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5313 /* 5314 * We are here likely because the receiver had its rwnd 5315 * closed for a while and we have not been able to 5316 * transmit the locally queued data within the maximum 5317 * retransmission attempts limit. Start the T5 5318 * shutdown guard timer to give the receiver one last 5319 * chance and some additional time to recover before 5320 * aborting. 5321 */ 5322 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5323 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5324 } else { 5325 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5326 SCTP_ERROR(ETIMEDOUT)); 5327 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5328 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5329 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5330 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5331 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5332 return SCTP_DISPOSITION_DELETE_TCB; 5333 } 5334 } 5335 5336 /* E1) For the destination address for which the timer 5337 * expires, adjust its ssthresh with rules defined in Section 5338 * 7.2.3 and set the cwnd <- MTU. 5339 */ 5340 5341 /* E2) For the destination address for which the timer 5342 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5343 * maximum value discussed in rule C7 above (RTO.max) may be 5344 * used to provide an upper bound to this doubling operation. 5345 */ 5346 5347 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5348 * outstanding DATA chunks for the address for which the 5349 * T3-rtx has expired will fit into a single packet, subject 5350 * to the MTU constraint for the path corresponding to the 5351 * destination transport address to which the retransmission 5352 * is being sent (this may be different from the address for 5353 * which the timer expires [see Section 6.4]). Call this 5354 * value K. Bundle and retransmit those K DATA chunks in a 5355 * single packet to the destination endpoint. 5356 * 5357 * Note: Any DATA chunks that were sent to the address for 5358 * which the T3-rtx timer expired but did not fit in one MTU 5359 * (rule E3 above), should be marked for retransmission and 5360 * sent as soon as cwnd allows (normally when a SACK arrives). 5361 */ 5362 5363 /* Do some failure management (Section 8.2). */ 5364 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5365 5366 /* NB: Rules E4 and F1 are implicit in R1. */ 5367 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5368 5369 return SCTP_DISPOSITION_CONSUME; 5370 } 5371 5372 /* 5373 * Generate delayed SACK on timeout 5374 * 5375 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5376 * 5377 * The guidelines on delayed acknowledgement algorithm specified in 5378 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5379 * acknowledgement SHOULD be generated for at least every second packet 5380 * (not every second DATA chunk) received, and SHOULD be generated 5381 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5382 * some situations it may be beneficial for an SCTP transmitter to be 5383 * more conservative than the algorithms detailed in this document 5384 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5385 * the following algorithms allow. 5386 */ 5387 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 5388 const struct sctp_association *asoc, 5389 const sctp_subtype_t type, 5390 void *arg, 5391 sctp_cmd_seq_t *commands) 5392 { 5393 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS); 5394 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5395 return SCTP_DISPOSITION_CONSUME; 5396 } 5397 5398 /* 5399 * sctp_sf_t1_init_timer_expire 5400 * 5401 * Section: 4 Note: 2 5402 * Verification Tag: 5403 * Inputs 5404 * (endpoint, asoc) 5405 * 5406 * RFC 2960 Section 4 Notes 5407 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5408 * and re-start the T1-init timer without changing state. This MUST 5409 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5410 * endpoint MUST abort the initialization process and report the 5411 * error to SCTP user. 5412 * 5413 * Outputs 5414 * (timers, events) 5415 * 5416 */ 5417 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 5418 const struct sctp_association *asoc, 5419 const sctp_subtype_t type, 5420 void *arg, 5421 sctp_cmd_seq_t *commands) 5422 { 5423 struct sctp_chunk *repl = NULL; 5424 struct sctp_bind_addr *bp; 5425 int attempts = asoc->init_err_counter + 1; 5426 5427 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5428 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS); 5429 5430 if (attempts <= asoc->max_init_attempts) { 5431 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5432 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5433 if (!repl) 5434 return SCTP_DISPOSITION_NOMEM; 5435 5436 /* Choose transport for INIT. */ 5437 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5438 SCTP_CHUNK(repl)); 5439 5440 /* Issue a sideeffect to do the needed accounting. */ 5441 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5442 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5443 5444 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5445 } else { 5446 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5447 " max_init_attempts: %d\n", 5448 attempts, asoc->max_init_attempts); 5449 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5450 SCTP_ERROR(ETIMEDOUT)); 5451 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5452 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5453 return SCTP_DISPOSITION_DELETE_TCB; 5454 } 5455 5456 return SCTP_DISPOSITION_CONSUME; 5457 } 5458 5459 /* 5460 * sctp_sf_t1_cookie_timer_expire 5461 * 5462 * Section: 4 Note: 2 5463 * Verification Tag: 5464 * Inputs 5465 * (endpoint, asoc) 5466 * 5467 * RFC 2960 Section 4 Notes 5468 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5469 * COOKIE ECHO and re-start the T1-cookie timer without changing 5470 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5471 * After that, the endpoint MUST abort the initialization process and 5472 * report the error to SCTP user. 5473 * 5474 * Outputs 5475 * (timers, events) 5476 * 5477 */ 5478 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 5479 const struct sctp_association *asoc, 5480 const sctp_subtype_t type, 5481 void *arg, 5482 sctp_cmd_seq_t *commands) 5483 { 5484 struct sctp_chunk *repl = NULL; 5485 int attempts = asoc->init_err_counter + 1; 5486 5487 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5488 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS); 5489 5490 if (attempts <= asoc->max_init_attempts) { 5491 repl = sctp_make_cookie_echo(asoc, NULL); 5492 if (!repl) 5493 return SCTP_DISPOSITION_NOMEM; 5494 5495 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5496 SCTP_CHUNK(repl)); 5497 /* Issue a sideeffect to do the needed accounting. */ 5498 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5499 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5500 5501 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5502 } else { 5503 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5504 SCTP_ERROR(ETIMEDOUT)); 5505 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5506 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5507 return SCTP_DISPOSITION_DELETE_TCB; 5508 } 5509 5510 return SCTP_DISPOSITION_CONSUME; 5511 } 5512 5513 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5514 * with the updated last sequential TSN received from its peer. 5515 * 5516 * An endpoint should limit the number of retransmissions of the 5517 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5518 * If this threshold is exceeded the endpoint should destroy the TCB and 5519 * MUST report the peer endpoint unreachable to the upper layer (and 5520 * thus the association enters the CLOSED state). The reception of any 5521 * packet from its peer (i.e. as the peer sends all of its queued DATA 5522 * chunks) should clear the endpoint's retransmission count and restart 5523 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5524 * all of its queued DATA chunks that have not yet been sent. 5525 */ 5526 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 5527 const struct sctp_association *asoc, 5528 const sctp_subtype_t type, 5529 void *arg, 5530 sctp_cmd_seq_t *commands) 5531 { 5532 struct sctp_chunk *reply = NULL; 5533 5534 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 5535 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5536 5537 ((struct sctp_association *)asoc)->shutdown_retries++; 5538 5539 if (asoc->overall_error_count >= asoc->max_retrans) { 5540 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5541 SCTP_ERROR(ETIMEDOUT)); 5542 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5543 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5544 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5545 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5546 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5547 return SCTP_DISPOSITION_DELETE_TCB; 5548 } 5549 5550 switch (asoc->state) { 5551 case SCTP_STATE_SHUTDOWN_SENT: 5552 reply = sctp_make_shutdown(asoc, NULL); 5553 break; 5554 5555 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5556 reply = sctp_make_shutdown_ack(asoc, NULL); 5557 break; 5558 5559 default: 5560 BUG(); 5561 break; 5562 } 5563 5564 if (!reply) 5565 goto nomem; 5566 5567 /* Do some failure management (Section 8.2). 5568 * If we remove the transport an SHUTDOWN was last sent to, don't 5569 * do failure management. 5570 */ 5571 if (asoc->shutdown_last_sent_to) 5572 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5573 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5574 5575 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5576 * the T2-shutdown timer. 5577 */ 5578 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5579 5580 /* Restart the T2-shutdown timer. */ 5581 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5582 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5583 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5584 return SCTP_DISPOSITION_CONSUME; 5585 5586 nomem: 5587 return SCTP_DISPOSITION_NOMEM; 5588 } 5589 5590 /* 5591 * ADDIP Section 4.1 ASCONF CHunk Procedures 5592 * If the T4 RTO timer expires the endpoint should do B1 to B5 5593 */ 5594 sctp_disposition_t sctp_sf_t4_timer_expire( 5595 const struct sctp_endpoint *ep, 5596 const struct sctp_association *asoc, 5597 const sctp_subtype_t type, 5598 void *arg, 5599 sctp_cmd_seq_t *commands) 5600 { 5601 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5602 struct sctp_transport *transport = chunk->transport; 5603 5604 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS); 5605 5606 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5607 * detection on the appropriate destination address as defined in 5608 * RFC2960 [5] section 8.1 and 8.2. 5609 */ 5610 if (transport) 5611 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5612 SCTP_TRANSPORT(transport)); 5613 5614 /* Reconfig T4 timer and transport. */ 5615 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5616 5617 /* ADDIP 4.1 B2) Increment the association error counters and perform 5618 * endpoint failure detection on the association as defined in 5619 * RFC2960 [5] section 8.1 and 8.2. 5620 * association error counter is incremented in SCTP_CMD_STRIKE. 5621 */ 5622 if (asoc->overall_error_count >= asoc->max_retrans) { 5623 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5624 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5625 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5626 SCTP_ERROR(ETIMEDOUT)); 5627 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5628 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5629 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5630 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5631 return SCTP_DISPOSITION_ABORT; 5632 } 5633 5634 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5635 * the ASCONF chunk was sent by doubling the RTO timer value. 5636 * This is done in SCTP_CMD_STRIKE. 5637 */ 5638 5639 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5640 * choose an alternate destination address (please refer to RFC2960 5641 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5642 * chunk, it MUST be the same (including its serial number) as the last 5643 * ASCONF sent. 5644 */ 5645 sctp_chunk_hold(asoc->addip_last_asconf); 5646 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5647 SCTP_CHUNK(asoc->addip_last_asconf)); 5648 5649 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5650 * destination is selected, then the RTO used will be that of the new 5651 * destination address. 5652 */ 5653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5654 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5655 5656 return SCTP_DISPOSITION_CONSUME; 5657 } 5658 5659 /* sctpimpguide-05 Section 2.12.2 5660 * The sender of the SHUTDOWN MAY also start an overall guard timer 5661 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5662 * At the expiration of this timer the sender SHOULD abort the association 5663 * by sending an ABORT chunk. 5664 */ 5665 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 5666 const struct sctp_association *asoc, 5667 const sctp_subtype_t type, 5668 void *arg, 5669 sctp_cmd_seq_t *commands) 5670 { 5671 struct sctp_chunk *reply = NULL; 5672 5673 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5674 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5675 5676 reply = sctp_make_abort(asoc, NULL, 0); 5677 if (!reply) 5678 goto nomem; 5679 5680 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5681 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5682 SCTP_ERROR(ETIMEDOUT)); 5683 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5684 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5685 5686 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5687 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5688 5689 return SCTP_DISPOSITION_DELETE_TCB; 5690 nomem: 5691 return SCTP_DISPOSITION_NOMEM; 5692 } 5693 5694 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5695 * the association is automatically closed by starting the shutdown process. 5696 * The work that needs to be done is same as when SHUTDOWN is initiated by 5697 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5698 */ 5699 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5700 const struct sctp_endpoint *ep, 5701 const struct sctp_association *asoc, 5702 const sctp_subtype_t type, 5703 void *arg, 5704 sctp_cmd_seq_t *commands) 5705 { 5706 int disposition; 5707 5708 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS); 5709 5710 /* From 9.2 Shutdown of an Association 5711 * Upon receipt of the SHUTDOWN primitive from its upper 5712 * layer, the endpoint enters SHUTDOWN-PENDING state and 5713 * remains there until all outstanding data has been 5714 * acknowledged by its peer. The endpoint accepts no new data 5715 * from its upper layer, but retransmits data to the far end 5716 * if necessary to fill gaps. 5717 */ 5718 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5719 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5720 5721 disposition = SCTP_DISPOSITION_CONSUME; 5722 if (sctp_outq_is_empty(&asoc->outqueue)) { 5723 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 5724 arg, commands); 5725 } 5726 return disposition; 5727 } 5728 5729 /***************************************************************************** 5730 * These are sa state functions which could apply to all types of events. 5731 ****************************************************************************/ 5732 5733 /* 5734 * This table entry is not implemented. 5735 * 5736 * Inputs 5737 * (endpoint, asoc, chunk) 5738 * 5739 * The return value is the disposition of the chunk. 5740 */ 5741 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 5742 const struct sctp_association *asoc, 5743 const sctp_subtype_t type, 5744 void *arg, 5745 sctp_cmd_seq_t *commands) 5746 { 5747 return SCTP_DISPOSITION_NOT_IMPL; 5748 } 5749 5750 /* 5751 * This table entry represents a bug. 5752 * 5753 * Inputs 5754 * (endpoint, asoc, chunk) 5755 * 5756 * The return value is the disposition of the chunk. 5757 */ 5758 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 5759 const struct sctp_association *asoc, 5760 const sctp_subtype_t type, 5761 void *arg, 5762 sctp_cmd_seq_t *commands) 5763 { 5764 return SCTP_DISPOSITION_BUG; 5765 } 5766 5767 /* 5768 * This table entry represents the firing of a timer in the wrong state. 5769 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5770 * when the association is in the wrong state. This event should 5771 * be ignored, so as to prevent any rearming of the timer. 5772 * 5773 * Inputs 5774 * (endpoint, asoc, chunk) 5775 * 5776 * The return value is the disposition of the chunk. 5777 */ 5778 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 5779 const struct sctp_association *asoc, 5780 const sctp_subtype_t type, 5781 void *arg, 5782 sctp_cmd_seq_t *commands) 5783 { 5784 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5785 return SCTP_DISPOSITION_CONSUME; 5786 } 5787 5788 /******************************************************************** 5789 * 2nd Level Abstractions 5790 ********************************************************************/ 5791 5792 /* Pull the SACK chunk based on the SACK header. */ 5793 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5794 { 5795 struct sctp_sackhdr *sack; 5796 unsigned int len; 5797 __u16 num_blocks; 5798 __u16 num_dup_tsns; 5799 5800 /* Protect ourselves from reading too far into 5801 * the skb from a bogus sender. 5802 */ 5803 sack = (struct sctp_sackhdr *) chunk->skb->data; 5804 5805 num_blocks = ntohs(sack->num_gap_ack_blocks); 5806 num_dup_tsns = ntohs(sack->num_dup_tsns); 5807 len = sizeof(struct sctp_sackhdr); 5808 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5809 if (len > chunk->skb->len) 5810 return NULL; 5811 5812 skb_pull(chunk->skb, len); 5813 5814 return sack; 5815 } 5816 5817 /* Create an ABORT packet to be sent as a response, with the specified 5818 * error causes. 5819 */ 5820 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5821 const struct sctp_association *asoc, 5822 struct sctp_chunk *chunk, 5823 const void *payload, 5824 size_t paylen) 5825 { 5826 struct sctp_packet *packet; 5827 struct sctp_chunk *abort; 5828 5829 packet = sctp_ootb_pkt_new(asoc, chunk); 5830 5831 if (packet) { 5832 /* Make an ABORT. 5833 * The T bit will be set if the asoc is NULL. 5834 */ 5835 abort = sctp_make_abort(asoc, chunk, paylen); 5836 if (!abort) { 5837 sctp_ootb_pkt_free(packet); 5838 return NULL; 5839 } 5840 5841 /* Reflect vtag if T-Bit is set */ 5842 if (sctp_test_T_bit(abort)) 5843 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5844 5845 /* Add specified error causes, i.e., payload, to the 5846 * end of the chunk. 5847 */ 5848 sctp_addto_chunk(abort, paylen, payload); 5849 5850 /* Set the skb to the belonging sock for accounting. */ 5851 abort->skb->sk = ep->base.sk; 5852 5853 sctp_packet_append_chunk(packet, abort); 5854 5855 } 5856 5857 return packet; 5858 } 5859 5860 /* Allocate a packet for responding in the OOTB conditions. */ 5861 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5862 const struct sctp_chunk *chunk) 5863 { 5864 struct sctp_packet *packet; 5865 struct sctp_transport *transport; 5866 __u16 sport; 5867 __u16 dport; 5868 __u32 vtag; 5869 5870 /* Get the source and destination port from the inbound packet. */ 5871 sport = ntohs(chunk->sctp_hdr->dest); 5872 dport = ntohs(chunk->sctp_hdr->source); 5873 5874 /* The V-tag is going to be the same as the inbound packet if no 5875 * association exists, otherwise, use the peer's vtag. 5876 */ 5877 if (asoc) { 5878 /* Special case the INIT-ACK as there is no peer's vtag 5879 * yet. 5880 */ 5881 switch(chunk->chunk_hdr->type) { 5882 case SCTP_CID_INIT_ACK: 5883 { 5884 sctp_initack_chunk_t *initack; 5885 5886 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5887 vtag = ntohl(initack->init_hdr.init_tag); 5888 break; 5889 } 5890 default: 5891 vtag = asoc->peer.i.init_tag; 5892 break; 5893 } 5894 } else { 5895 /* Special case the INIT and stale COOKIE_ECHO as there is no 5896 * vtag yet. 5897 */ 5898 switch(chunk->chunk_hdr->type) { 5899 case SCTP_CID_INIT: 5900 { 5901 sctp_init_chunk_t *init; 5902 5903 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5904 vtag = ntohl(init->init_hdr.init_tag); 5905 break; 5906 } 5907 default: 5908 vtag = ntohl(chunk->sctp_hdr->vtag); 5909 break; 5910 } 5911 } 5912 5913 /* Make a transport for the bucket, Eliza... */ 5914 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5915 if (!transport) 5916 goto nomem; 5917 5918 /* Cache a route for the transport with the chunk's destination as 5919 * the source address. 5920 */ 5921 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5922 sctp_sk(sctp_get_ctl_sock())); 5923 5924 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5925 packet = sctp_packet_config(packet, vtag, 0); 5926 5927 return packet; 5928 5929 nomem: 5930 return NULL; 5931 } 5932 5933 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5934 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5935 { 5936 sctp_transport_free(packet->transport); 5937 } 5938 5939 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5940 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5941 const struct sctp_association *asoc, 5942 const struct sctp_chunk *chunk, 5943 sctp_cmd_seq_t *commands, 5944 struct sctp_chunk *err_chunk) 5945 { 5946 struct sctp_packet *packet; 5947 5948 if (err_chunk) { 5949 packet = sctp_ootb_pkt_new(asoc, chunk); 5950 if (packet) { 5951 struct sctp_signed_cookie *cookie; 5952 5953 /* Override the OOTB vtag from the cookie. */ 5954 cookie = chunk->subh.cookie_hdr; 5955 packet->vtag = cookie->c.peer_vtag; 5956 5957 /* Set the skb to the belonging sock for accounting. */ 5958 err_chunk->skb->sk = ep->base.sk; 5959 sctp_packet_append_chunk(packet, err_chunk); 5960 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5961 SCTP_PACKET(packet)); 5962 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5963 } else 5964 sctp_chunk_free (err_chunk); 5965 } 5966 } 5967 5968 5969 /* Process a data chunk */ 5970 static int sctp_eat_data(const struct sctp_association *asoc, 5971 struct sctp_chunk *chunk, 5972 sctp_cmd_seq_t *commands) 5973 { 5974 sctp_datahdr_t *data_hdr; 5975 struct sctp_chunk *err; 5976 size_t datalen; 5977 sctp_verb_t deliver; 5978 int tmp; 5979 __u32 tsn; 5980 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 5981 struct sock *sk = asoc->base.sk; 5982 u16 ssn; 5983 u16 sid; 5984 u8 ordered = 0; 5985 5986 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5987 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5988 5989 tsn = ntohl(data_hdr->tsn); 5990 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5991 5992 /* ASSERT: Now skb->data is really the user data. */ 5993 5994 /* Process ECN based congestion. 5995 * 5996 * Since the chunk structure is reused for all chunks within 5997 * a packet, we use ecn_ce_done to track if we've already 5998 * done CE processing for this packet. 5999 * 6000 * We need to do ECN processing even if we plan to discard the 6001 * chunk later. 6002 */ 6003 6004 if (!chunk->ecn_ce_done) { 6005 struct sctp_af *af; 6006 chunk->ecn_ce_done = 1; 6007 6008 af = sctp_get_af_specific( 6009 ipver2af(ip_hdr(chunk->skb)->version)); 6010 6011 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 6012 /* Do real work as sideffect. */ 6013 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6014 SCTP_U32(tsn)); 6015 } 6016 } 6017 6018 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6019 if (tmp < 0) { 6020 /* The TSN is too high--silently discard the chunk and 6021 * count on it getting retransmitted later. 6022 */ 6023 return SCTP_IERROR_HIGH_TSN; 6024 } else if (tmp > 0) { 6025 /* This is a duplicate. Record it. */ 6026 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6027 return SCTP_IERROR_DUP_TSN; 6028 } 6029 6030 /* This is a new TSN. */ 6031 6032 /* Discard if there is no room in the receive window. 6033 * Actually, allow a little bit of overflow (up to a MTU). 6034 */ 6035 datalen = ntohs(chunk->chunk_hdr->length); 6036 datalen -= sizeof(sctp_data_chunk_t); 6037 6038 deliver = SCTP_CMD_CHUNK_ULP; 6039 6040 /* Think about partial delivery. */ 6041 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6042 6043 /* Even if we don't accept this chunk there is 6044 * memory pressure. 6045 */ 6046 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6047 } 6048 6049 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6050 * seems a bit troublesome in that frag_point varies based on 6051 * PMTU. In cases, such as loopback, this might be a rather 6052 * large spill over. 6053 */ 6054 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6055 (datalen > asoc->rwnd + asoc->frag_point))) { 6056 6057 /* If this is the next TSN, consider reneging to make 6058 * room. Note: Playing nice with a confused sender. A 6059 * malicious sender can still eat up all our buffer 6060 * space and in the future we may want to detect and 6061 * do more drastic reneging. 6062 */ 6063 if (sctp_tsnmap_has_gap(map) && 6064 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6065 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 6066 deliver = SCTP_CMD_RENEGE; 6067 } else { 6068 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 6069 "rwnd: %d\n", tsn, datalen, 6070 asoc->rwnd); 6071 return SCTP_IERROR_IGNORE_TSN; 6072 } 6073 } 6074 6075 /* 6076 * Also try to renege to limit our memory usage in the event that 6077 * we are under memory pressure 6078 * If we can't renege, don't worry about it, the sk_rmem_schedule 6079 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6080 * memory usage too much 6081 */ 6082 if (*sk->sk_prot_creator->memory_pressure) { 6083 if (sctp_tsnmap_has_gap(map) && 6084 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6085 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 6086 deliver = SCTP_CMD_RENEGE; 6087 } 6088 } 6089 6090 /* 6091 * Section 3.3.10.9 No User Data (9) 6092 * 6093 * Cause of error 6094 * --------------- 6095 * No User Data: This error cause is returned to the originator of a 6096 * DATA chunk if a received DATA chunk has no user data. 6097 */ 6098 if (unlikely(0 == datalen)) { 6099 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6100 if (err) { 6101 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6102 SCTP_CHUNK(err)); 6103 } 6104 /* We are going to ABORT, so we might as well stop 6105 * processing the rest of the chunks in the packet. 6106 */ 6107 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 6108 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6109 SCTP_ERROR(ECONNABORTED)); 6110 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6111 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6112 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 6113 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 6114 return SCTP_IERROR_NO_DATA; 6115 } 6116 6117 chunk->data_accepted = 1; 6118 6119 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6120 * if we renege and the chunk arrives again. 6121 */ 6122 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 6123 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 6124 else { 6125 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 6126 ordered = 1; 6127 } 6128 6129 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6130 * 6131 * If an endpoint receive a DATA chunk with an invalid stream 6132 * identifier, it shall acknowledge the reception of the DATA chunk 6133 * following the normal procedure, immediately send an ERROR chunk 6134 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6135 * and discard the DATA chunk. 6136 */ 6137 sid = ntohs(data_hdr->stream); 6138 if (sid >= asoc->c.sinit_max_instreams) { 6139 /* Mark tsn as received even though we drop it */ 6140 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6141 6142 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6143 &data_hdr->stream, 6144 sizeof(data_hdr->stream), 6145 sizeof(u16)); 6146 if (err) 6147 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6148 SCTP_CHUNK(err)); 6149 return SCTP_IERROR_BAD_STREAM; 6150 } 6151 6152 /* Check to see if the SSN is possible for this TSN. 6153 * The biggest gap we can record is 4K wide. Since SSNs wrap 6154 * at an unsigned short, there is no way that an SSN can 6155 * wrap and for a valid TSN. We can simply check if the current 6156 * SSN is smaller then the next expected one. If it is, it wrapped 6157 * and is invalid. 6158 */ 6159 ssn = ntohs(data_hdr->ssn); 6160 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6161 return SCTP_IERROR_PROTO_VIOLATION; 6162 } 6163 6164 /* Send the data up to the user. Note: Schedule the 6165 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6166 * chunk needs the updated rwnd. 6167 */ 6168 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6169 6170 return SCTP_IERROR_NO_ERROR; 6171 } 6172