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