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 " 1127 NIP6_FMT "\n", 1128 __func__, 1129 asoc, 1130 NIP6(from_addr.v6.sin6_addr)); 1131 } else { 1132 if (net_ratelimit()) 1133 printk(KERN_WARNING 1134 "%s association %p could not find address " 1135 NIPQUAD_FMT "\n", 1136 __func__, 1137 asoc, 1138 NIPQUAD(from_addr.v4.sin_addr.s_addr)); 1139 } 1140 return SCTP_DISPOSITION_DISCARD; 1141 } 1142 1143 /* Validate the 64-bit random nonce. */ 1144 if (hbinfo->hb_nonce != link->hb_nonce) 1145 return SCTP_DISPOSITION_DISCARD; 1146 1147 max_interval = link->hbinterval + link->rto; 1148 1149 /* Check if the timestamp looks valid. */ 1150 if (time_after(hbinfo->sent_at, jiffies) || 1151 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1152 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp " 1153 "received for transport: %p\n", 1154 __func__, link); 1155 return SCTP_DISPOSITION_DISCARD; 1156 } 1157 1158 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1159 * the HEARTBEAT should clear the error counter of the 1160 * destination transport address to which the HEARTBEAT was 1161 * sent and mark the destination transport address as active if 1162 * it is not so marked. 1163 */ 1164 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1165 1166 return SCTP_DISPOSITION_CONSUME; 1167 } 1168 1169 /* Helper function to send out an abort for the restart 1170 * condition. 1171 */ 1172 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1173 struct sctp_chunk *init, 1174 sctp_cmd_seq_t *commands) 1175 { 1176 int len; 1177 struct sctp_packet *pkt; 1178 union sctp_addr_param *addrparm; 1179 struct sctp_errhdr *errhdr; 1180 struct sctp_endpoint *ep; 1181 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1182 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1183 1184 /* Build the error on the stack. We are way to malloc crazy 1185 * throughout the code today. 1186 */ 1187 errhdr = (struct sctp_errhdr *)buffer; 1188 addrparm = (union sctp_addr_param *)errhdr->variable; 1189 1190 /* Copy into a parm format. */ 1191 len = af->to_addr_param(ssa, addrparm); 1192 len += sizeof(sctp_errhdr_t); 1193 1194 errhdr->cause = SCTP_ERROR_RESTART; 1195 errhdr->length = htons(len); 1196 1197 /* Assign to the control socket. */ 1198 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1199 1200 /* Association is NULL since this may be a restart attack and we 1201 * want to send back the attacker's vtag. 1202 */ 1203 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1204 1205 if (!pkt) 1206 goto out; 1207 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1208 1209 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1210 1211 /* Discard the rest of the inbound packet. */ 1212 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1213 1214 out: 1215 /* Even if there is no memory, treat as a failure so 1216 * the packet will get dropped. 1217 */ 1218 return 0; 1219 } 1220 1221 /* A restart is occurring, check to make sure no new addresses 1222 * are being added as we may be under a takeover attack. 1223 */ 1224 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1225 const struct sctp_association *asoc, 1226 struct sctp_chunk *init, 1227 sctp_cmd_seq_t *commands) 1228 { 1229 struct sctp_transport *new_addr, *addr; 1230 int found; 1231 1232 /* Implementor's Guide - Sectin 5.2.2 1233 * ... 1234 * Before responding the endpoint MUST check to see if the 1235 * unexpected INIT adds new addresses to the association. If new 1236 * addresses are added to the association, the endpoint MUST respond 1237 * with an ABORT.. 1238 */ 1239 1240 /* Search through all current addresses and make sure 1241 * we aren't adding any new ones. 1242 */ 1243 new_addr = NULL; 1244 found = 0; 1245 1246 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1247 transports) { 1248 found = 0; 1249 list_for_each_entry(addr, &asoc->peer.transport_addr_list, 1250 transports) { 1251 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1252 &addr->ipaddr)) { 1253 found = 1; 1254 break; 1255 } 1256 } 1257 if (!found) 1258 break; 1259 } 1260 1261 /* If a new address was added, ABORT the sender. */ 1262 if (!found && new_addr) { 1263 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1264 } 1265 1266 /* Return success if all addresses were found. */ 1267 return found; 1268 } 1269 1270 /* Populate the verification/tie tags based on overlapping INIT 1271 * scenario. 1272 * 1273 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1274 */ 1275 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1276 const struct sctp_association *asoc) 1277 { 1278 switch (asoc->state) { 1279 1280 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1281 1282 case SCTP_STATE_COOKIE_WAIT: 1283 new_asoc->c.my_vtag = asoc->c.my_vtag; 1284 new_asoc->c.my_ttag = asoc->c.my_vtag; 1285 new_asoc->c.peer_ttag = 0; 1286 break; 1287 1288 case SCTP_STATE_COOKIE_ECHOED: 1289 new_asoc->c.my_vtag = asoc->c.my_vtag; 1290 new_asoc->c.my_ttag = asoc->c.my_vtag; 1291 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1292 break; 1293 1294 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1295 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1296 */ 1297 default: 1298 new_asoc->c.my_ttag = asoc->c.my_vtag; 1299 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1300 break; 1301 } 1302 1303 /* Other parameters for the endpoint SHOULD be copied from the 1304 * existing parameters of the association (e.g. number of 1305 * outbound streams) into the INIT ACK and cookie. 1306 */ 1307 new_asoc->rwnd = asoc->rwnd; 1308 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1309 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1310 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1311 } 1312 1313 /* 1314 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1315 * handling action. 1316 * 1317 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1318 * 1319 * Returns value representing action to be taken. These action values 1320 * correspond to Action/Description values in RFC 2960, Table 2. 1321 */ 1322 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1323 const struct sctp_association *asoc) 1324 { 1325 /* In this case, the peer may have restarted. */ 1326 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1327 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1328 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1329 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1330 return 'A'; 1331 1332 /* Collision case B. */ 1333 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1334 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1335 (0 == asoc->c.peer_vtag))) { 1336 return 'B'; 1337 } 1338 1339 /* Collision case D. */ 1340 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1341 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1342 return 'D'; 1343 1344 /* Collision case C. */ 1345 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1346 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1347 (0 == new_asoc->c.my_ttag) && 1348 (0 == new_asoc->c.peer_ttag)) 1349 return 'C'; 1350 1351 /* No match to any of the special cases; discard this packet. */ 1352 return 'E'; 1353 } 1354 1355 /* Common helper routine for both duplicate and simulataneous INIT 1356 * chunk handling. 1357 */ 1358 static sctp_disposition_t sctp_sf_do_unexpected_init( 1359 const struct sctp_endpoint *ep, 1360 const struct sctp_association *asoc, 1361 const sctp_subtype_t type, 1362 void *arg, sctp_cmd_seq_t *commands) 1363 { 1364 sctp_disposition_t retval; 1365 struct sctp_chunk *chunk = arg; 1366 struct sctp_chunk *repl; 1367 struct sctp_association *new_asoc; 1368 struct sctp_chunk *err_chunk; 1369 struct sctp_packet *packet; 1370 sctp_unrecognized_param_t *unk_param; 1371 int len; 1372 1373 /* 6.10 Bundling 1374 * An endpoint MUST NOT bundle INIT, INIT ACK or 1375 * SHUTDOWN COMPLETE with any other chunks. 1376 * 1377 * IG Section 2.11.2 1378 * Furthermore, we require that the receiver of an INIT chunk MUST 1379 * enforce these rules by silently discarding an arriving packet 1380 * with an INIT chunk that is bundled with other chunks. 1381 */ 1382 if (!chunk->singleton) 1383 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1384 1385 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1386 * Tag. 1387 */ 1388 if (chunk->sctp_hdr->vtag != 0) 1389 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1390 1391 /* Make sure that the INIT chunk has a valid length. 1392 * In this case, we generate a protocol violation since we have 1393 * an association established. 1394 */ 1395 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1396 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1397 commands); 1398 /* Grab the INIT header. */ 1399 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1400 1401 /* Tag the variable length parameters. */ 1402 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1403 1404 /* Verify the INIT chunk before processing it. */ 1405 err_chunk = NULL; 1406 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1407 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1408 &err_chunk)) { 1409 /* This chunk contains fatal error. It is to be discarded. 1410 * Send an ABORT, with causes if there is any. 1411 */ 1412 if (err_chunk) { 1413 packet = sctp_abort_pkt_new(ep, asoc, arg, 1414 (__u8 *)(err_chunk->chunk_hdr) + 1415 sizeof(sctp_chunkhdr_t), 1416 ntohs(err_chunk->chunk_hdr->length) - 1417 sizeof(sctp_chunkhdr_t)); 1418 1419 if (packet) { 1420 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1421 SCTP_PACKET(packet)); 1422 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1423 retval = SCTP_DISPOSITION_CONSUME; 1424 } else { 1425 retval = SCTP_DISPOSITION_NOMEM; 1426 } 1427 goto cleanup; 1428 } else { 1429 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1430 commands); 1431 } 1432 } 1433 1434 /* 1435 * Other parameters for the endpoint SHOULD be copied from the 1436 * existing parameters of the association (e.g. number of 1437 * outbound streams) into the INIT ACK and cookie. 1438 * FIXME: We are copying parameters from the endpoint not the 1439 * association. 1440 */ 1441 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1442 if (!new_asoc) 1443 goto nomem; 1444 1445 /* In the outbound INIT ACK the endpoint MUST copy its current 1446 * Verification Tag and Peers Verification tag into a reserved 1447 * place (local tie-tag and per tie-tag) within the state cookie. 1448 */ 1449 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1450 sctp_source(chunk), 1451 (sctp_init_chunk_t *)chunk->chunk_hdr, 1452 GFP_ATOMIC)) 1453 goto nomem; 1454 1455 /* Make sure no new addresses are being added during the 1456 * restart. Do not do this check for COOKIE-WAIT state, 1457 * since there are no peer addresses to check against. 1458 * Upon return an ABORT will have been sent if needed. 1459 */ 1460 if (!sctp_state(asoc, COOKIE_WAIT)) { 1461 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1462 commands)) { 1463 retval = SCTP_DISPOSITION_CONSUME; 1464 goto nomem_retval; 1465 } 1466 } 1467 1468 sctp_tietags_populate(new_asoc, asoc); 1469 1470 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1471 1472 /* If there are errors need to be reported for unknown parameters, 1473 * make sure to reserve enough room in the INIT ACK for them. 1474 */ 1475 len = 0; 1476 if (err_chunk) { 1477 len = ntohs(err_chunk->chunk_hdr->length) - 1478 sizeof(sctp_chunkhdr_t); 1479 } 1480 1481 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 1482 goto nomem; 1483 1484 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1485 if (!repl) 1486 goto nomem; 1487 1488 /* If there are errors need to be reported for unknown parameters, 1489 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1490 * parameter. 1491 */ 1492 if (err_chunk) { 1493 /* Get the "Unrecognized parameter" parameter(s) out of the 1494 * ERROR chunk generated by sctp_verify_init(). Since the 1495 * error cause code for "unknown parameter" and the 1496 * "Unrecognized parameter" type is the same, we can 1497 * construct the parameters in INIT ACK by copying the 1498 * ERROR causes over. 1499 */ 1500 unk_param = (sctp_unrecognized_param_t *) 1501 ((__u8 *)(err_chunk->chunk_hdr) + 1502 sizeof(sctp_chunkhdr_t)); 1503 /* Replace the cause code with the "Unrecognized parameter" 1504 * parameter type. 1505 */ 1506 sctp_addto_chunk(repl, len, unk_param); 1507 } 1508 1509 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1510 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1511 1512 /* 1513 * Note: After sending out INIT ACK with the State Cookie parameter, 1514 * "Z" MUST NOT allocate any resources for this new association. 1515 * Otherwise, "Z" will be vulnerable to resource attacks. 1516 */ 1517 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1518 retval = SCTP_DISPOSITION_CONSUME; 1519 1520 return retval; 1521 1522 nomem: 1523 retval = SCTP_DISPOSITION_NOMEM; 1524 nomem_retval: 1525 if (new_asoc) 1526 sctp_association_free(new_asoc); 1527 cleanup: 1528 if (err_chunk) 1529 sctp_chunk_free(err_chunk); 1530 return retval; 1531 } 1532 1533 /* 1534 * Handle simultanous INIT. 1535 * This means we started an INIT and then we got an INIT request from 1536 * our peer. 1537 * 1538 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1539 * This usually indicates an initialization collision, i.e., each 1540 * endpoint is attempting, at about the same time, to establish an 1541 * association with the other endpoint. 1542 * 1543 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1544 * endpoint MUST respond with an INIT ACK using the same parameters it 1545 * sent in its original INIT chunk (including its Verification Tag, 1546 * unchanged). These original parameters are combined with those from the 1547 * newly received INIT chunk. The endpoint shall also generate a State 1548 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1549 * INIT to calculate the State Cookie. 1550 * 1551 * After that, the endpoint MUST NOT change its state, the T1-init 1552 * timer shall be left running and the corresponding TCB MUST NOT be 1553 * destroyed. The normal procedures for handling State Cookies when 1554 * a TCB exists will resolve the duplicate INITs to a single association. 1555 * 1556 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1557 * its Tie-Tags with the Tag information of itself and its peer (see 1558 * section 5.2.2 for a description of the Tie-Tags). 1559 * 1560 * Verification Tag: Not explicit, but an INIT can not have a valid 1561 * verification tag, so we skip the check. 1562 * 1563 * Inputs 1564 * (endpoint, asoc, chunk) 1565 * 1566 * Outputs 1567 * (asoc, reply_msg, msg_up, timers, counters) 1568 * 1569 * The return value is the disposition of the chunk. 1570 */ 1571 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1572 const struct sctp_association *asoc, 1573 const sctp_subtype_t type, 1574 void *arg, 1575 sctp_cmd_seq_t *commands) 1576 { 1577 /* Call helper to do the real work for both simulataneous and 1578 * duplicate INIT chunk handling. 1579 */ 1580 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1581 } 1582 1583 /* 1584 * Handle duplicated INIT messages. These are usually delayed 1585 * restransmissions. 1586 * 1587 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1588 * COOKIE-ECHOED and COOKIE-WAIT 1589 * 1590 * Unless otherwise stated, upon reception of an unexpected INIT for 1591 * this association, the endpoint shall generate an INIT ACK with a 1592 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1593 * current Verification Tag and peer's Verification Tag into a reserved 1594 * place within the state cookie. We shall refer to these locations as 1595 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1596 * containing this INIT ACK MUST carry a Verification Tag value equal to 1597 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1598 * MUST contain a new Initiation Tag (randomly generated see Section 1599 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1600 * existing parameters of the association (e.g. number of outbound 1601 * streams) into the INIT ACK and cookie. 1602 * 1603 * After sending out the INIT ACK, the endpoint shall take no further 1604 * actions, i.e., the existing association, including its current state, 1605 * and the corresponding TCB MUST NOT be changed. 1606 * 1607 * Note: Only when a TCB exists and the association is not in a COOKIE- 1608 * WAIT state are the Tie-Tags populated. For a normal association INIT 1609 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1610 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1611 * State Cookie are populated as specified in section 5.2.1. 1612 * 1613 * Verification Tag: Not specified, but an INIT has no way of knowing 1614 * what the verification tag could be, so we ignore it. 1615 * 1616 * Inputs 1617 * (endpoint, asoc, chunk) 1618 * 1619 * Outputs 1620 * (asoc, reply_msg, msg_up, timers, counters) 1621 * 1622 * The return value is the disposition of the chunk. 1623 */ 1624 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1625 const struct sctp_association *asoc, 1626 const sctp_subtype_t type, 1627 void *arg, 1628 sctp_cmd_seq_t *commands) 1629 { 1630 /* Call helper to do the real work for both simulataneous and 1631 * duplicate INIT chunk handling. 1632 */ 1633 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1634 } 1635 1636 1637 /* 1638 * Unexpected INIT-ACK handler. 1639 * 1640 * Section 5.2.3 1641 * If an INIT ACK received by an endpoint in any state other than the 1642 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1643 * An unexpected INIT ACK usually indicates the processing of an old or 1644 * duplicated INIT chunk. 1645 */ 1646 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep, 1647 const struct sctp_association *asoc, 1648 const sctp_subtype_t type, 1649 void *arg, sctp_cmd_seq_t *commands) 1650 { 1651 /* Per the above section, we'll discard the chunk if we have an 1652 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1653 */ 1654 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 1655 return sctp_sf_ootb(ep, asoc, type, arg, commands); 1656 else 1657 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 1658 } 1659 1660 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1661 * 1662 * Section 5.2.4 1663 * A) In this case, the peer may have restarted. 1664 */ 1665 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1666 const struct sctp_association *asoc, 1667 struct sctp_chunk *chunk, 1668 sctp_cmd_seq_t *commands, 1669 struct sctp_association *new_asoc) 1670 { 1671 sctp_init_chunk_t *peer_init; 1672 struct sctp_ulpevent *ev; 1673 struct sctp_chunk *repl; 1674 struct sctp_chunk *err; 1675 sctp_disposition_t disposition; 1676 1677 /* new_asoc is a brand-new association, so these are not yet 1678 * side effects--it is safe to run them here. 1679 */ 1680 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1681 1682 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1683 sctp_source(chunk), peer_init, 1684 GFP_ATOMIC)) 1685 goto nomem; 1686 1687 /* Make sure no new addresses are being added during the 1688 * restart. Though this is a pretty complicated attack 1689 * since you'd have to get inside the cookie. 1690 */ 1691 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1692 return SCTP_DISPOSITION_CONSUME; 1693 } 1694 1695 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1696 * the peer has restarted (Action A), it MUST NOT setup a new 1697 * association but instead resend the SHUTDOWN ACK and send an ERROR 1698 * chunk with a "Cookie Received while Shutting Down" error cause to 1699 * its peer. 1700 */ 1701 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1702 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1703 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1704 chunk, commands); 1705 if (SCTP_DISPOSITION_NOMEM == disposition) 1706 goto nomem; 1707 1708 err = sctp_make_op_error(asoc, chunk, 1709 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1710 NULL, 0); 1711 if (err) 1712 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1713 SCTP_CHUNK(err)); 1714 1715 return SCTP_DISPOSITION_CONSUME; 1716 } 1717 1718 /* For now, fail any unsent/unacked data. Consider the optional 1719 * choice of resending of this data. 1720 */ 1721 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1722 1723 repl = sctp_make_cookie_ack(new_asoc, chunk); 1724 if (!repl) 1725 goto nomem; 1726 1727 /* Report association restart to upper layer. */ 1728 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1729 new_asoc->c.sinit_num_ostreams, 1730 new_asoc->c.sinit_max_instreams, 1731 NULL, GFP_ATOMIC); 1732 if (!ev) 1733 goto nomem_ev; 1734 1735 /* Update the content of current association. */ 1736 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1737 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1738 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1739 return SCTP_DISPOSITION_CONSUME; 1740 1741 nomem_ev: 1742 sctp_chunk_free(repl); 1743 nomem: 1744 return SCTP_DISPOSITION_NOMEM; 1745 } 1746 1747 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1748 * 1749 * Section 5.2.4 1750 * B) In this case, both sides may be attempting to start an association 1751 * at about the same time but the peer endpoint started its INIT 1752 * after responding to the local endpoint's INIT 1753 */ 1754 /* This case represents an initialization collision. */ 1755 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1756 const struct sctp_association *asoc, 1757 struct sctp_chunk *chunk, 1758 sctp_cmd_seq_t *commands, 1759 struct sctp_association *new_asoc) 1760 { 1761 sctp_init_chunk_t *peer_init; 1762 struct sctp_chunk *repl; 1763 1764 /* new_asoc is a brand-new association, so these are not yet 1765 * side effects--it is safe to run them here. 1766 */ 1767 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1768 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1769 sctp_source(chunk), peer_init, 1770 GFP_ATOMIC)) 1771 goto nomem; 1772 1773 /* Update the content of current association. */ 1774 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1775 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1776 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1777 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1778 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1779 1780 repl = sctp_make_cookie_ack(new_asoc, chunk); 1781 if (!repl) 1782 goto nomem; 1783 1784 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1785 1786 /* RFC 2960 5.1 Normal Establishment of an Association 1787 * 1788 * D) IMPLEMENTATION NOTE: An implementation may choose to 1789 * send the Communication Up notification to the SCTP user 1790 * upon reception of a valid COOKIE ECHO chunk. 1791 * 1792 * Sadly, this needs to be implemented as a side-effect, because 1793 * we are not guaranteed to have set the association id of the real 1794 * association and so these notifications need to be delayed until 1795 * the association id is allocated. 1796 */ 1797 1798 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1799 1800 /* Sockets API Draft Section 5.3.1.6 1801 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1802 * delivers this notification to inform the application that of the 1803 * peers requested adaptation layer. 1804 * 1805 * This also needs to be done as a side effect for the same reason as 1806 * above. 1807 */ 1808 if (asoc->peer.adaptation_ind) 1809 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1810 1811 return SCTP_DISPOSITION_CONSUME; 1812 1813 nomem: 1814 return SCTP_DISPOSITION_NOMEM; 1815 } 1816 1817 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1818 * 1819 * Section 5.2.4 1820 * C) In this case, the local endpoint's cookie has arrived late. 1821 * Before it arrived, the local endpoint sent an INIT and received an 1822 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1823 * but a new tag of its own. 1824 */ 1825 /* This case represents an initialization collision. */ 1826 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1827 const struct sctp_association *asoc, 1828 struct sctp_chunk *chunk, 1829 sctp_cmd_seq_t *commands, 1830 struct sctp_association *new_asoc) 1831 { 1832 /* The cookie should be silently discarded. 1833 * The endpoint SHOULD NOT change states and should leave 1834 * any timers running. 1835 */ 1836 return SCTP_DISPOSITION_DISCARD; 1837 } 1838 1839 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1840 * 1841 * Section 5.2.4 1842 * 1843 * D) When both local and remote tags match the endpoint should always 1844 * enter the ESTABLISHED state, if it has not already done so. 1845 */ 1846 /* This case represents an initialization collision. */ 1847 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1848 const struct sctp_association *asoc, 1849 struct sctp_chunk *chunk, 1850 sctp_cmd_seq_t *commands, 1851 struct sctp_association *new_asoc) 1852 { 1853 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1854 struct sctp_chunk *repl; 1855 1856 /* Clarification from Implementor's Guide: 1857 * D) When both local and remote tags match the endpoint should 1858 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1859 * It should stop any cookie timer that may be running and send 1860 * a COOKIE ACK. 1861 */ 1862 1863 /* Don't accidentally move back into established state. */ 1864 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1865 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1866 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1867 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1868 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1869 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1870 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1871 SCTP_NULL()); 1872 1873 /* RFC 2960 5.1 Normal Establishment of an Association 1874 * 1875 * D) IMPLEMENTATION NOTE: An implementation may choose 1876 * to send the Communication Up notification to the 1877 * SCTP user upon reception of a valid COOKIE 1878 * ECHO chunk. 1879 */ 1880 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1881 SCTP_COMM_UP, 0, 1882 asoc->c.sinit_num_ostreams, 1883 asoc->c.sinit_max_instreams, 1884 NULL, GFP_ATOMIC); 1885 if (!ev) 1886 goto nomem; 1887 1888 /* Sockets API Draft Section 5.3.1.6 1889 * When a peer sends a Adaptation Layer Indication parameter, 1890 * SCTP delivers this notification to inform the application 1891 * that of the peers requested adaptation layer. 1892 */ 1893 if (asoc->peer.adaptation_ind) { 1894 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1895 GFP_ATOMIC); 1896 if (!ai_ev) 1897 goto nomem; 1898 1899 } 1900 } 1901 1902 repl = sctp_make_cookie_ack(new_asoc, chunk); 1903 if (!repl) 1904 goto nomem; 1905 1906 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1907 1908 if (ev) 1909 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1910 SCTP_ULPEVENT(ev)); 1911 if (ai_ev) 1912 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1913 SCTP_ULPEVENT(ai_ev)); 1914 1915 return SCTP_DISPOSITION_CONSUME; 1916 1917 nomem: 1918 if (ai_ev) 1919 sctp_ulpevent_free(ai_ev); 1920 if (ev) 1921 sctp_ulpevent_free(ev); 1922 return SCTP_DISPOSITION_NOMEM; 1923 } 1924 1925 /* 1926 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1927 * chunk was retransmitted and then delayed in the network. 1928 * 1929 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1930 * 1931 * Verification Tag: None. Do cookie validation. 1932 * 1933 * Inputs 1934 * (endpoint, asoc, chunk) 1935 * 1936 * Outputs 1937 * (asoc, reply_msg, msg_up, timers, counters) 1938 * 1939 * The return value is the disposition of the chunk. 1940 */ 1941 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1942 const struct sctp_association *asoc, 1943 const sctp_subtype_t type, 1944 void *arg, 1945 sctp_cmd_seq_t *commands) 1946 { 1947 sctp_disposition_t retval; 1948 struct sctp_chunk *chunk = arg; 1949 struct sctp_association *new_asoc; 1950 int error = 0; 1951 char action; 1952 struct sctp_chunk *err_chk_p; 1953 1954 /* Make sure that the chunk has a valid length from the protocol 1955 * perspective. In this case check to make sure we have at least 1956 * enough for the chunk header. Cookie length verification is 1957 * done later. 1958 */ 1959 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1960 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1961 commands); 1962 1963 /* "Decode" the chunk. We have no optional parameters so we 1964 * are in good shape. 1965 */ 1966 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1967 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1968 sizeof(sctp_chunkhdr_t))) 1969 goto nomem; 1970 1971 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1972 * of a duplicate COOKIE ECHO match the Verification Tags of the 1973 * current association, consider the State Cookie valid even if 1974 * the lifespan is exceeded. 1975 */ 1976 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1977 &err_chk_p); 1978 1979 /* FIXME: 1980 * If the re-build failed, what is the proper error path 1981 * from here? 1982 * 1983 * [We should abort the association. --piggy] 1984 */ 1985 if (!new_asoc) { 1986 /* FIXME: Several errors are possible. A bad cookie should 1987 * be silently discarded, but think about logging it too. 1988 */ 1989 switch (error) { 1990 case -SCTP_IERROR_NOMEM: 1991 goto nomem; 1992 1993 case -SCTP_IERROR_STALE_COOKIE: 1994 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 1995 err_chk_p); 1996 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1997 case -SCTP_IERROR_BAD_SIG: 1998 default: 1999 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2000 } 2001 } 2002 2003 /* Compare the tie_tag in cookie with the verification tag of 2004 * current association. 2005 */ 2006 action = sctp_tietags_compare(new_asoc, asoc); 2007 2008 switch (action) { 2009 case 'A': /* Association restart. */ 2010 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 2011 new_asoc); 2012 break; 2013 2014 case 'B': /* Collision case B. */ 2015 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 2016 new_asoc); 2017 break; 2018 2019 case 'C': /* Collision case C. */ 2020 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 2021 new_asoc); 2022 break; 2023 2024 case 'D': /* Collision case D. */ 2025 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 2026 new_asoc); 2027 break; 2028 2029 default: /* Discard packet for all others. */ 2030 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2031 break; 2032 } 2033 2034 /* Delete the tempory new association. */ 2035 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2036 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2037 2038 return retval; 2039 2040 nomem: 2041 return SCTP_DISPOSITION_NOMEM; 2042 } 2043 2044 /* 2045 * Process an ABORT. (SHUTDOWN-PENDING state) 2046 * 2047 * See sctp_sf_do_9_1_abort(). 2048 */ 2049 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2050 const struct sctp_endpoint *ep, 2051 const struct sctp_association *asoc, 2052 const sctp_subtype_t type, 2053 void *arg, 2054 sctp_cmd_seq_t *commands) 2055 { 2056 struct sctp_chunk *chunk = arg; 2057 2058 if (!sctp_vtag_verify_either(chunk, asoc)) 2059 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2060 2061 /* Make sure that the ABORT chunk has a valid length. 2062 * Since this is an ABORT chunk, we have to discard it 2063 * because of the following text: 2064 * RFC 2960, Section 3.3.7 2065 * If an endpoint receives an ABORT with a format error or for an 2066 * association that doesn't exist, it MUST silently discard it. 2067 * Becasue the length is "invalid", we can't really discard just 2068 * as we do not know its true length. So, to be safe, discard the 2069 * packet. 2070 */ 2071 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2072 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2073 2074 /* ADD-IP: Special case for ABORT chunks 2075 * F4) One special consideration is that ABORT Chunks arriving 2076 * destined to the IP address being deleted MUST be 2077 * ignored (see Section 5.3.1 for further details). 2078 */ 2079 if (SCTP_ADDR_DEL == 2080 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2081 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2082 2083 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2084 } 2085 2086 /* 2087 * Process an ABORT. (SHUTDOWN-SENT state) 2088 * 2089 * See sctp_sf_do_9_1_abort(). 2090 */ 2091 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 2092 const struct sctp_association *asoc, 2093 const sctp_subtype_t type, 2094 void *arg, 2095 sctp_cmd_seq_t *commands) 2096 { 2097 struct sctp_chunk *chunk = arg; 2098 2099 if (!sctp_vtag_verify_either(chunk, asoc)) 2100 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2101 2102 /* Make sure that the ABORT chunk has a valid length. 2103 * Since this is an ABORT chunk, we have to discard it 2104 * because of the following text: 2105 * RFC 2960, Section 3.3.7 2106 * If an endpoint receives an ABORT with a format error or for an 2107 * association that doesn't exist, it MUST silently discard it. 2108 * Becasue the length is "invalid", we can't really discard just 2109 * as we do not know its true length. So, to be safe, discard the 2110 * packet. 2111 */ 2112 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2113 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2114 2115 /* ADD-IP: Special case for ABORT chunks 2116 * F4) One special consideration is that ABORT Chunks arriving 2117 * destined to the IP address being deleted MUST be 2118 * ignored (see Section 5.3.1 for further details). 2119 */ 2120 if (SCTP_ADDR_DEL == 2121 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2122 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2123 2124 /* Stop the T2-shutdown timer. */ 2125 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2126 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2127 2128 /* Stop the T5-shutdown guard timer. */ 2129 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2130 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2131 2132 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2133 } 2134 2135 /* 2136 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2137 * 2138 * See sctp_sf_do_9_1_abort(). 2139 */ 2140 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2141 const struct sctp_endpoint *ep, 2142 const struct sctp_association *asoc, 2143 const sctp_subtype_t type, 2144 void *arg, 2145 sctp_cmd_seq_t *commands) 2146 { 2147 /* The same T2 timer, so we should be able to use 2148 * common function with the SHUTDOWN-SENT state. 2149 */ 2150 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2151 } 2152 2153 /* 2154 * Handle an Error received in COOKIE_ECHOED state. 2155 * 2156 * Only handle the error type of stale COOKIE Error, the other errors will 2157 * be ignored. 2158 * 2159 * Inputs 2160 * (endpoint, asoc, chunk) 2161 * 2162 * Outputs 2163 * (asoc, reply_msg, msg_up, timers, counters) 2164 * 2165 * The return value is the disposition of the chunk. 2166 */ 2167 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2168 const struct sctp_association *asoc, 2169 const sctp_subtype_t type, 2170 void *arg, 2171 sctp_cmd_seq_t *commands) 2172 { 2173 struct sctp_chunk *chunk = arg; 2174 sctp_errhdr_t *err; 2175 2176 if (!sctp_vtag_verify(chunk, asoc)) 2177 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2178 2179 /* Make sure that the ERROR chunk has a valid length. 2180 * The parameter walking depends on this as well. 2181 */ 2182 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2183 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2184 commands); 2185 2186 /* Process the error here */ 2187 /* FUTURE FIXME: When PR-SCTP related and other optional 2188 * parms are emitted, this will have to change to handle multiple 2189 * errors. 2190 */ 2191 sctp_walk_errors(err, chunk->chunk_hdr) { 2192 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2193 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2194 arg, commands); 2195 } 2196 2197 /* It is possible to have malformed error causes, and that 2198 * will cause us to end the walk early. However, since 2199 * we are discarding the packet, there should be no adverse 2200 * affects. 2201 */ 2202 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2203 } 2204 2205 /* 2206 * Handle a Stale COOKIE Error 2207 * 2208 * Section: 5.2.6 Handle Stale COOKIE Error 2209 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2210 * one of the following three alternatives. 2211 * ... 2212 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2213 * Preservative parameter requesting an extension to the lifetime of 2214 * the State Cookie. When calculating the time extension, an 2215 * implementation SHOULD use the RTT information measured based on the 2216 * previous COOKIE ECHO / ERROR exchange, and should add no more 2217 * than 1 second beyond the measured RTT, due to long State Cookie 2218 * lifetimes making the endpoint more subject to a replay attack. 2219 * 2220 * Verification Tag: Not explicit, but safe to ignore. 2221 * 2222 * Inputs 2223 * (endpoint, asoc, chunk) 2224 * 2225 * Outputs 2226 * (asoc, reply_msg, msg_up, timers, counters) 2227 * 2228 * The return value is the disposition of the chunk. 2229 */ 2230 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2231 const struct sctp_association *asoc, 2232 const sctp_subtype_t type, 2233 void *arg, 2234 sctp_cmd_seq_t *commands) 2235 { 2236 struct sctp_chunk *chunk = arg; 2237 time_t stale; 2238 sctp_cookie_preserve_param_t bht; 2239 sctp_errhdr_t *err; 2240 struct sctp_chunk *reply; 2241 struct sctp_bind_addr *bp; 2242 int attempts = asoc->init_err_counter + 1; 2243 2244 if (attempts > asoc->max_init_attempts) { 2245 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2246 SCTP_ERROR(ETIMEDOUT)); 2247 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2248 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2249 return SCTP_DISPOSITION_DELETE_TCB; 2250 } 2251 2252 err = (sctp_errhdr_t *)(chunk->skb->data); 2253 2254 /* When calculating the time extension, an implementation 2255 * SHOULD use the RTT information measured based on the 2256 * previous COOKIE ECHO / ERROR exchange, and should add no 2257 * more than 1 second beyond the measured RTT, due to long 2258 * State Cookie lifetimes making the endpoint more subject to 2259 * a replay attack. 2260 * Measure of Staleness's unit is usec. (1/1000000 sec) 2261 * Suggested Cookie Life-span Increment's unit is msec. 2262 * (1/1000 sec) 2263 * In general, if you use the suggested cookie life, the value 2264 * found in the field of measure of staleness should be doubled 2265 * to give ample time to retransmit the new cookie and thus 2266 * yield a higher probability of success on the reattempt. 2267 */ 2268 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2269 stale = (stale * 2) / 1000; 2270 2271 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2272 bht.param_hdr.length = htons(sizeof(bht)); 2273 bht.lifespan_increment = htonl(stale); 2274 2275 /* Build that new INIT chunk. */ 2276 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2277 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2278 if (!reply) 2279 goto nomem; 2280 2281 sctp_addto_chunk(reply, sizeof(bht), &bht); 2282 2283 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2284 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2285 2286 /* Stop pending T3-rtx and heartbeat timers */ 2287 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2288 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2289 2290 /* Delete non-primary peer ip addresses since we are transitioning 2291 * back to the COOKIE-WAIT state 2292 */ 2293 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2294 2295 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2296 * resend 2297 */ 2298 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2299 SCTP_TRANSPORT(asoc->peer.primary_path)); 2300 2301 /* Cast away the const modifier, as we want to just 2302 * rerun it through as a sideffect. 2303 */ 2304 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2305 2306 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2307 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2308 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2309 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2310 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2311 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2312 2313 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2314 2315 return SCTP_DISPOSITION_CONSUME; 2316 2317 nomem: 2318 return SCTP_DISPOSITION_NOMEM; 2319 } 2320 2321 /* 2322 * Process an ABORT. 2323 * 2324 * Section: 9.1 2325 * After checking the Verification Tag, the receiving endpoint shall 2326 * remove the association from its record, and shall report the 2327 * termination to its upper layer. 2328 * 2329 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2330 * B) Rules for packet carrying ABORT: 2331 * 2332 * - The endpoint shall always fill in the Verification Tag field of the 2333 * outbound packet with the destination endpoint's tag value if it 2334 * is known. 2335 * 2336 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2337 * MUST follow the procedure described in Section 8.4. 2338 * 2339 * - The receiver MUST accept the packet if the Verification Tag 2340 * matches either its own tag, OR the tag of its peer. Otherwise, the 2341 * receiver MUST silently discard the packet and take no further 2342 * action. 2343 * 2344 * Inputs 2345 * (endpoint, asoc, chunk) 2346 * 2347 * Outputs 2348 * (asoc, reply_msg, msg_up, timers, counters) 2349 * 2350 * The return value is the disposition of the chunk. 2351 */ 2352 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2353 const struct sctp_association *asoc, 2354 const sctp_subtype_t type, 2355 void *arg, 2356 sctp_cmd_seq_t *commands) 2357 { 2358 struct sctp_chunk *chunk = arg; 2359 2360 if (!sctp_vtag_verify_either(chunk, asoc)) 2361 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2362 2363 /* Make sure that the ABORT chunk has a valid length. 2364 * Since this is an ABORT chunk, we have to discard it 2365 * because of the following text: 2366 * RFC 2960, Section 3.3.7 2367 * If an endpoint receives an ABORT with a format error or for an 2368 * association that doesn't exist, it MUST silently discard it. 2369 * Becasue the length is "invalid", we can't really discard just 2370 * as we do not know its true length. So, to be safe, discard the 2371 * packet. 2372 */ 2373 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2374 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2375 2376 /* ADD-IP: Special case for ABORT chunks 2377 * F4) One special consideration is that ABORT Chunks arriving 2378 * destined to the IP address being deleted MUST be 2379 * ignored (see Section 5.3.1 for further details). 2380 */ 2381 if (SCTP_ADDR_DEL == 2382 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2383 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2384 2385 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2386 } 2387 2388 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2389 const struct sctp_association *asoc, 2390 const sctp_subtype_t type, 2391 void *arg, 2392 sctp_cmd_seq_t *commands) 2393 { 2394 struct sctp_chunk *chunk = arg; 2395 unsigned len; 2396 __be16 error = SCTP_ERROR_NO_ERROR; 2397 2398 /* See if we have an error cause code in the chunk. */ 2399 len = ntohs(chunk->chunk_hdr->length); 2400 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2401 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2402 2403 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2404 /* ASSOC_FAILED will DELETE_TCB. */ 2405 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2406 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2407 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2408 2409 return SCTP_DISPOSITION_ABORT; 2410 } 2411 2412 /* 2413 * Process an ABORT. (COOKIE-WAIT state) 2414 * 2415 * See sctp_sf_do_9_1_abort() above. 2416 */ 2417 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2418 const struct sctp_association *asoc, 2419 const sctp_subtype_t type, 2420 void *arg, 2421 sctp_cmd_seq_t *commands) 2422 { 2423 struct sctp_chunk *chunk = arg; 2424 unsigned len; 2425 __be16 error = SCTP_ERROR_NO_ERROR; 2426 2427 if (!sctp_vtag_verify_either(chunk, asoc)) 2428 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2429 2430 /* Make sure that the ABORT chunk has a valid length. 2431 * Since this is an ABORT chunk, we have to discard it 2432 * because of the following text: 2433 * RFC 2960, Section 3.3.7 2434 * If an endpoint receives an ABORT with a format error or for an 2435 * association that doesn't exist, it MUST silently discard it. 2436 * Becasue the length is "invalid", we can't really discard just 2437 * as we do not know its true length. So, to be safe, discard the 2438 * packet. 2439 */ 2440 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2441 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2442 2443 /* See if we have an error cause code in the chunk. */ 2444 len = ntohs(chunk->chunk_hdr->length); 2445 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2446 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2447 2448 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, 2449 chunk->transport); 2450 } 2451 2452 /* 2453 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2454 */ 2455 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2456 const struct sctp_association *asoc, 2457 const sctp_subtype_t type, 2458 void *arg, 2459 sctp_cmd_seq_t *commands) 2460 { 2461 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, 2462 ENOPROTOOPT, asoc, 2463 (struct sctp_transport *)arg); 2464 } 2465 2466 /* 2467 * Process an ABORT. (COOKIE-ECHOED state) 2468 */ 2469 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2470 const struct sctp_association *asoc, 2471 const sctp_subtype_t type, 2472 void *arg, 2473 sctp_cmd_seq_t *commands) 2474 { 2475 /* There is a single T1 timer, so we should be able to use 2476 * common function with the COOKIE-WAIT state. 2477 */ 2478 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2479 } 2480 2481 /* 2482 * Stop T1 timer and abort association with "INIT failed". 2483 * 2484 * This is common code called by several sctp_sf_*_abort() functions above. 2485 */ 2486 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2487 __be16 error, int sk_err, 2488 const struct sctp_association *asoc, 2489 struct sctp_transport *transport) 2490 { 2491 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2492 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2493 SCTP_STATE(SCTP_STATE_CLOSED)); 2494 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2495 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2496 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2497 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2498 /* CMD_INIT_FAILED will DELETE_TCB. */ 2499 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2500 SCTP_PERR(error)); 2501 return SCTP_DISPOSITION_ABORT; 2502 } 2503 2504 /* 2505 * sctp_sf_do_9_2_shut 2506 * 2507 * Section: 9.2 2508 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2509 * - enter the SHUTDOWN-RECEIVED state, 2510 * 2511 * - stop accepting new data from its SCTP user 2512 * 2513 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2514 * that all its outstanding DATA chunks have been received by the 2515 * SHUTDOWN sender. 2516 * 2517 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2518 * send a SHUTDOWN in response to a ULP request. And should discard 2519 * subsequent SHUTDOWN chunks. 2520 * 2521 * If there are still outstanding DATA chunks left, the SHUTDOWN 2522 * receiver shall continue to follow normal data transmission 2523 * procedures defined in Section 6 until all outstanding DATA chunks 2524 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2525 * new data from its SCTP user. 2526 * 2527 * Verification Tag: 8.5 Verification Tag [Normal verification] 2528 * 2529 * Inputs 2530 * (endpoint, asoc, chunk) 2531 * 2532 * Outputs 2533 * (asoc, reply_msg, msg_up, timers, counters) 2534 * 2535 * The return value is the disposition of the chunk. 2536 */ 2537 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2538 const struct sctp_association *asoc, 2539 const sctp_subtype_t type, 2540 void *arg, 2541 sctp_cmd_seq_t *commands) 2542 { 2543 struct sctp_chunk *chunk = arg; 2544 sctp_shutdownhdr_t *sdh; 2545 sctp_disposition_t disposition; 2546 struct sctp_ulpevent *ev; 2547 2548 if (!sctp_vtag_verify(chunk, asoc)) 2549 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2550 2551 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2552 if (!sctp_chunk_length_valid(chunk, 2553 sizeof(struct sctp_shutdown_chunk_t))) 2554 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2555 commands); 2556 2557 /* Convert the elaborate header. */ 2558 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2559 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2560 chunk->subh.shutdown_hdr = sdh; 2561 2562 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2563 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2564 * inform the application that it should cease sending data. 2565 */ 2566 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2567 if (!ev) { 2568 disposition = SCTP_DISPOSITION_NOMEM; 2569 goto out; 2570 } 2571 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2572 2573 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2574 * - enter the SHUTDOWN-RECEIVED state, 2575 * - stop accepting new data from its SCTP user 2576 * 2577 * [This is implicit in the new state.] 2578 */ 2579 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2580 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2581 disposition = SCTP_DISPOSITION_CONSUME; 2582 2583 if (sctp_outq_is_empty(&asoc->outqueue)) { 2584 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2585 arg, commands); 2586 } 2587 2588 if (SCTP_DISPOSITION_NOMEM == disposition) 2589 goto out; 2590 2591 /* - verify, by checking the Cumulative TSN Ack field of the 2592 * chunk, that all its outstanding DATA chunks have been 2593 * received by the SHUTDOWN sender. 2594 */ 2595 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2596 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2597 2598 out: 2599 return disposition; 2600 } 2601 2602 /* RFC 2960 9.2 2603 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2604 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2605 * transport addresses (either in the IP addresses or in the INIT chunk) 2606 * that belong to this association, it should discard the INIT chunk and 2607 * retransmit the SHUTDOWN ACK chunk. 2608 */ 2609 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2610 const struct sctp_association *asoc, 2611 const sctp_subtype_t type, 2612 void *arg, 2613 sctp_cmd_seq_t *commands) 2614 { 2615 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2616 struct sctp_chunk *reply; 2617 2618 /* Make sure that the chunk has a valid length */ 2619 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2620 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2621 commands); 2622 2623 /* Since we are not going to really process this INIT, there 2624 * is no point in verifying chunk boundries. Just generate 2625 * the SHUTDOWN ACK. 2626 */ 2627 reply = sctp_make_shutdown_ack(asoc, chunk); 2628 if (NULL == reply) 2629 goto nomem; 2630 2631 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2632 * the T2-SHUTDOWN timer. 2633 */ 2634 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2635 2636 /* and restart the T2-shutdown timer. */ 2637 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2638 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2639 2640 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2641 2642 return SCTP_DISPOSITION_CONSUME; 2643 nomem: 2644 return SCTP_DISPOSITION_NOMEM; 2645 } 2646 2647 /* 2648 * sctp_sf_do_ecn_cwr 2649 * 2650 * Section: Appendix A: Explicit Congestion Notification 2651 * 2652 * CWR: 2653 * 2654 * RFC 2481 details a specific bit for a sender to send in the header of 2655 * its next outbound TCP segment to indicate to its peer that it has 2656 * reduced its congestion window. This is termed the CWR bit. For 2657 * SCTP the same indication is made by including the CWR chunk. 2658 * This chunk contains one data element, i.e. the TSN number that 2659 * was sent in the ECNE chunk. This element represents the lowest 2660 * TSN number in the datagram that was originally marked with the 2661 * CE bit. 2662 * 2663 * Verification Tag: 8.5 Verification Tag [Normal verification] 2664 * Inputs 2665 * (endpoint, asoc, chunk) 2666 * 2667 * Outputs 2668 * (asoc, reply_msg, msg_up, timers, counters) 2669 * 2670 * The return value is the disposition of the chunk. 2671 */ 2672 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2673 const struct sctp_association *asoc, 2674 const sctp_subtype_t type, 2675 void *arg, 2676 sctp_cmd_seq_t *commands) 2677 { 2678 sctp_cwrhdr_t *cwr; 2679 struct sctp_chunk *chunk = arg; 2680 u32 lowest_tsn; 2681 2682 if (!sctp_vtag_verify(chunk, asoc)) 2683 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2684 2685 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2686 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2687 commands); 2688 2689 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2690 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2691 2692 lowest_tsn = ntohl(cwr->lowest_tsn); 2693 2694 /* Does this CWR ack the last sent congestion notification? */ 2695 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2696 /* Stop sending ECNE. */ 2697 sctp_add_cmd_sf(commands, 2698 SCTP_CMD_ECN_CWR, 2699 SCTP_U32(lowest_tsn)); 2700 } 2701 return SCTP_DISPOSITION_CONSUME; 2702 } 2703 2704 /* 2705 * sctp_sf_do_ecne 2706 * 2707 * Section: Appendix A: Explicit Congestion Notification 2708 * 2709 * ECN-Echo 2710 * 2711 * RFC 2481 details a specific bit for a receiver to send back in its 2712 * TCP acknowledgements to notify the sender of the Congestion 2713 * Experienced (CE) bit having arrived from the network. For SCTP this 2714 * same indication is made by including the ECNE chunk. This chunk 2715 * contains one data element, i.e. the lowest TSN associated with the IP 2716 * datagram marked with the CE bit..... 2717 * 2718 * Verification Tag: 8.5 Verification Tag [Normal verification] 2719 * Inputs 2720 * (endpoint, asoc, chunk) 2721 * 2722 * Outputs 2723 * (asoc, reply_msg, msg_up, timers, counters) 2724 * 2725 * The return value is the disposition of the chunk. 2726 */ 2727 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2728 const struct sctp_association *asoc, 2729 const sctp_subtype_t type, 2730 void *arg, 2731 sctp_cmd_seq_t *commands) 2732 { 2733 sctp_ecnehdr_t *ecne; 2734 struct sctp_chunk *chunk = arg; 2735 2736 if (!sctp_vtag_verify(chunk, asoc)) 2737 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2738 2739 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2740 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2741 commands); 2742 2743 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2744 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2745 2746 /* If this is a newer ECNE than the last CWR packet we sent out */ 2747 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2748 SCTP_U32(ntohl(ecne->lowest_tsn))); 2749 2750 return SCTP_DISPOSITION_CONSUME; 2751 } 2752 2753 /* 2754 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2755 * 2756 * The SCTP endpoint MUST always acknowledge the reception of each valid 2757 * DATA chunk. 2758 * 2759 * The guidelines on delayed acknowledgement algorithm specified in 2760 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2761 * acknowledgement SHOULD be generated for at least every second packet 2762 * (not every second DATA chunk) received, and SHOULD be generated within 2763 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2764 * situations it may be beneficial for an SCTP transmitter to be more 2765 * conservative than the algorithms detailed in this document allow. 2766 * However, an SCTP transmitter MUST NOT be more aggressive than the 2767 * following algorithms allow. 2768 * 2769 * A SCTP receiver MUST NOT generate more than one SACK for every 2770 * incoming packet, other than to update the offered window as the 2771 * receiving application consumes new data. 2772 * 2773 * Verification Tag: 8.5 Verification Tag [Normal verification] 2774 * 2775 * Inputs 2776 * (endpoint, asoc, chunk) 2777 * 2778 * Outputs 2779 * (asoc, reply_msg, msg_up, timers, counters) 2780 * 2781 * The return value is the disposition of the chunk. 2782 */ 2783 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2784 const struct sctp_association *asoc, 2785 const sctp_subtype_t type, 2786 void *arg, 2787 sctp_cmd_seq_t *commands) 2788 { 2789 struct sctp_chunk *chunk = arg; 2790 int error; 2791 2792 if (!sctp_vtag_verify(chunk, asoc)) { 2793 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2794 SCTP_NULL()); 2795 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2796 } 2797 2798 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2799 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2800 commands); 2801 2802 error = sctp_eat_data(asoc, chunk, commands ); 2803 switch (error) { 2804 case SCTP_IERROR_NO_ERROR: 2805 break; 2806 case SCTP_IERROR_HIGH_TSN: 2807 case SCTP_IERROR_BAD_STREAM: 2808 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2809 goto discard_noforce; 2810 case SCTP_IERROR_DUP_TSN: 2811 case SCTP_IERROR_IGNORE_TSN: 2812 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2813 goto discard_force; 2814 case SCTP_IERROR_NO_DATA: 2815 goto consume; 2816 default: 2817 BUG(); 2818 } 2819 2820 if (asoc->autoclose) { 2821 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2822 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2823 } 2824 2825 /* If this is the last chunk in a packet, we need to count it 2826 * toward sack generation. Note that we need to SACK every 2827 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2828 * THEM. We elect to NOT generate SACK's if the chunk fails 2829 * the verification tag test. 2830 * 2831 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2832 * 2833 * The SCTP endpoint MUST always acknowledge the reception of 2834 * each valid DATA chunk. 2835 * 2836 * The guidelines on delayed acknowledgement algorithm 2837 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2838 * Specifically, an acknowledgement SHOULD be generated for at 2839 * least every second packet (not every second DATA chunk) 2840 * received, and SHOULD be generated within 200 ms of the 2841 * arrival of any unacknowledged DATA chunk. In some 2842 * situations it may be beneficial for an SCTP transmitter to 2843 * be more conservative than the algorithms detailed in this 2844 * document allow. However, an SCTP transmitter MUST NOT be 2845 * more aggressive than the following algorithms allow. 2846 */ 2847 if (chunk->end_of_packet) 2848 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2849 2850 return SCTP_DISPOSITION_CONSUME; 2851 2852 discard_force: 2853 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2854 * 2855 * When a packet arrives with duplicate DATA chunk(s) and with 2856 * no new DATA chunk(s), the endpoint MUST immediately send a 2857 * SACK with no delay. If a packet arrives with duplicate 2858 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2859 * MAY immediately send a SACK. Normally receipt of duplicate 2860 * DATA chunks will occur when the original SACK chunk was lost 2861 * and the peer's RTO has expired. The duplicate TSN number(s) 2862 * SHOULD be reported in the SACK as duplicate. 2863 */ 2864 /* In our case, we split the MAY SACK advice up whether or not 2865 * the last chunk is a duplicate.' 2866 */ 2867 if (chunk->end_of_packet) 2868 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2869 return SCTP_DISPOSITION_DISCARD; 2870 2871 discard_noforce: 2872 if (chunk->end_of_packet) 2873 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2874 2875 return SCTP_DISPOSITION_DISCARD; 2876 consume: 2877 return SCTP_DISPOSITION_CONSUME; 2878 2879 } 2880 2881 /* 2882 * sctp_sf_eat_data_fast_4_4 2883 * 2884 * Section: 4 (4) 2885 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2886 * DATA chunks without delay. 2887 * 2888 * Verification Tag: 8.5 Verification Tag [Normal verification] 2889 * Inputs 2890 * (endpoint, asoc, chunk) 2891 * 2892 * Outputs 2893 * (asoc, reply_msg, msg_up, timers, counters) 2894 * 2895 * The return value is the disposition of the chunk. 2896 */ 2897 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2898 const struct sctp_association *asoc, 2899 const sctp_subtype_t type, 2900 void *arg, 2901 sctp_cmd_seq_t *commands) 2902 { 2903 struct sctp_chunk *chunk = arg; 2904 int error; 2905 2906 if (!sctp_vtag_verify(chunk, asoc)) { 2907 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2908 SCTP_NULL()); 2909 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2910 } 2911 2912 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2913 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2914 commands); 2915 2916 error = sctp_eat_data(asoc, chunk, commands ); 2917 switch (error) { 2918 case SCTP_IERROR_NO_ERROR: 2919 case SCTP_IERROR_HIGH_TSN: 2920 case SCTP_IERROR_DUP_TSN: 2921 case SCTP_IERROR_IGNORE_TSN: 2922 case SCTP_IERROR_BAD_STREAM: 2923 break; 2924 case SCTP_IERROR_NO_DATA: 2925 goto consume; 2926 default: 2927 BUG(); 2928 } 2929 2930 /* Go a head and force a SACK, since we are shutting down. */ 2931 2932 /* Implementor's Guide. 2933 * 2934 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 2935 * respond to each received packet containing one or more DATA chunk(s) 2936 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 2937 */ 2938 if (chunk->end_of_packet) { 2939 /* We must delay the chunk creation since the cumulative 2940 * TSN has not been updated yet. 2941 */ 2942 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 2943 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2944 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2945 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2946 } 2947 2948 consume: 2949 return SCTP_DISPOSITION_CONSUME; 2950 } 2951 2952 /* 2953 * Section: 6.2 Processing a Received SACK 2954 * D) Any time a SACK arrives, the endpoint performs the following: 2955 * 2956 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 2957 * then drop the SACK. Since Cumulative TSN Ack is monotonically 2958 * increasing, a SACK whose Cumulative TSN Ack is less than the 2959 * Cumulative TSN Ack Point indicates an out-of-order SACK. 2960 * 2961 * ii) Set rwnd equal to the newly received a_rwnd minus the number 2962 * of bytes still outstanding after processing the Cumulative TSN Ack 2963 * and the Gap Ack Blocks. 2964 * 2965 * iii) If the SACK is missing a TSN that was previously 2966 * acknowledged via a Gap Ack Block (e.g., the data receiver 2967 * reneged on the data), then mark the corresponding DATA chunk 2968 * as available for retransmit: Mark it as missing for fast 2969 * retransmit as described in Section 7.2.4 and if no retransmit 2970 * timer is running for the destination address to which the DATA 2971 * chunk was originally transmitted, then T3-rtx is started for 2972 * that destination address. 2973 * 2974 * Verification Tag: 8.5 Verification Tag [Normal verification] 2975 * 2976 * Inputs 2977 * (endpoint, asoc, chunk) 2978 * 2979 * Outputs 2980 * (asoc, reply_msg, msg_up, timers, counters) 2981 * 2982 * The return value is the disposition of the chunk. 2983 */ 2984 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 2985 const struct sctp_association *asoc, 2986 const sctp_subtype_t type, 2987 void *arg, 2988 sctp_cmd_seq_t *commands) 2989 { 2990 struct sctp_chunk *chunk = arg; 2991 sctp_sackhdr_t *sackh; 2992 __u32 ctsn; 2993 2994 if (!sctp_vtag_verify(chunk, asoc)) 2995 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2996 2997 /* Make sure that the SACK chunk has a valid length. */ 2998 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 2999 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3000 commands); 3001 3002 /* Pull the SACK chunk from the data buffer */ 3003 sackh = sctp_sm_pull_sack(chunk); 3004 /* Was this a bogus SACK? */ 3005 if (!sackh) 3006 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3007 chunk->subh.sack_hdr = sackh; 3008 ctsn = ntohl(sackh->cum_tsn_ack); 3009 3010 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3011 * Ack Point, then drop the SACK. Since Cumulative TSN 3012 * Ack is monotonically increasing, a SACK whose 3013 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3014 * Point indicates an out-of-order SACK. 3015 */ 3016 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3017 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3018 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3019 return SCTP_DISPOSITION_DISCARD; 3020 } 3021 3022 /* If Cumulative TSN Ack beyond the max tsn currently 3023 * send, terminating the association and respond to the 3024 * sender with an ABORT. 3025 */ 3026 if (!TSN_lt(ctsn, asoc->next_tsn)) 3027 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 3028 3029 /* Return this SACK for further processing. */ 3030 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 3031 3032 /* Note: We do the rest of the work on the PROCESS_SACK 3033 * sideeffect. 3034 */ 3035 return SCTP_DISPOSITION_CONSUME; 3036 } 3037 3038 /* 3039 * Generate an ABORT in response to a packet. 3040 * 3041 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3042 * 3043 * 8) The receiver should respond to the sender of the OOTB packet with 3044 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3045 * MUST fill in the Verification Tag field of the outbound packet 3046 * with the value found in the Verification Tag field of the OOTB 3047 * packet and set the T-bit in the Chunk Flags to indicate that the 3048 * Verification Tag is reflected. After sending this ABORT, the 3049 * receiver of the OOTB packet shall discard the OOTB packet and take 3050 * no further action. 3051 * 3052 * Verification Tag: 3053 * 3054 * The return value is the disposition of the chunk. 3055 */ 3056 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 3057 const struct sctp_association *asoc, 3058 const sctp_subtype_t type, 3059 void *arg, 3060 sctp_cmd_seq_t *commands) 3061 { 3062 struct sctp_packet *packet = NULL; 3063 struct sctp_chunk *chunk = arg; 3064 struct sctp_chunk *abort; 3065 3066 packet = sctp_ootb_pkt_new(asoc, chunk); 3067 3068 if (packet) { 3069 /* Make an ABORT. The T bit will be set if the asoc 3070 * is NULL. 3071 */ 3072 abort = sctp_make_abort(asoc, chunk, 0); 3073 if (!abort) { 3074 sctp_ootb_pkt_free(packet); 3075 return SCTP_DISPOSITION_NOMEM; 3076 } 3077 3078 /* Reflect vtag if T-Bit is set */ 3079 if (sctp_test_T_bit(abort)) 3080 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3081 3082 /* Set the skb to the belonging sock for accounting. */ 3083 abort->skb->sk = ep->base.sk; 3084 3085 sctp_packet_append_chunk(packet, abort); 3086 3087 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3088 SCTP_PACKET(packet)); 3089 3090 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3091 3092 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3093 return SCTP_DISPOSITION_CONSUME; 3094 } 3095 3096 return SCTP_DISPOSITION_NOMEM; 3097 } 3098 3099 /* 3100 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3101 * event as ULP notification for each cause included in the chunk. 3102 * 3103 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3104 * 3105 * The return value is the disposition of the chunk. 3106 */ 3107 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 3108 const struct sctp_association *asoc, 3109 const sctp_subtype_t type, 3110 void *arg, 3111 sctp_cmd_seq_t *commands) 3112 { 3113 struct sctp_chunk *chunk = arg; 3114 struct sctp_ulpevent *ev; 3115 3116 if (!sctp_vtag_verify(chunk, asoc)) 3117 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3118 3119 /* Make sure that the ERROR chunk has a valid length. */ 3120 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3121 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3122 commands); 3123 3124 while (chunk->chunk_end > chunk->skb->data) { 3125 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 3126 GFP_ATOMIC); 3127 if (!ev) 3128 goto nomem; 3129 3130 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3131 SCTP_ULPEVENT(ev)); 3132 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3133 SCTP_CHUNK(chunk)); 3134 } 3135 return SCTP_DISPOSITION_CONSUME; 3136 3137 nomem: 3138 return SCTP_DISPOSITION_NOMEM; 3139 } 3140 3141 /* 3142 * Process an inbound SHUTDOWN ACK. 3143 * 3144 * From Section 9.2: 3145 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3146 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3147 * peer, and remove all record of the association. 3148 * 3149 * The return value is the disposition. 3150 */ 3151 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3152 const struct sctp_association *asoc, 3153 const sctp_subtype_t type, 3154 void *arg, 3155 sctp_cmd_seq_t *commands) 3156 { 3157 struct sctp_chunk *chunk = arg; 3158 struct sctp_chunk *reply; 3159 struct sctp_ulpevent *ev; 3160 3161 if (!sctp_vtag_verify(chunk, asoc)) 3162 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3163 3164 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3165 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3166 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3167 commands); 3168 /* 10.2 H) SHUTDOWN COMPLETE notification 3169 * 3170 * When SCTP completes the shutdown procedures (section 9.2) this 3171 * notification is passed to the upper layer. 3172 */ 3173 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3174 0, 0, 0, NULL, GFP_ATOMIC); 3175 if (!ev) 3176 goto nomem; 3177 3178 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3179 reply = sctp_make_shutdown_complete(asoc, chunk); 3180 if (!reply) 3181 goto nomem_chunk; 3182 3183 /* Do all the commands now (after allocation), so that we 3184 * have consistent state if memory allocation failes 3185 */ 3186 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3187 3188 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3189 * stop the T2-shutdown timer, 3190 */ 3191 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3192 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3193 3194 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3195 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3196 3197 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3198 SCTP_STATE(SCTP_STATE_CLOSED)); 3199 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3200 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3201 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3202 3203 /* ...and remove all record of the association. */ 3204 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3205 return SCTP_DISPOSITION_DELETE_TCB; 3206 3207 nomem_chunk: 3208 sctp_ulpevent_free(ev); 3209 nomem: 3210 return SCTP_DISPOSITION_NOMEM; 3211 } 3212 3213 /* 3214 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3215 * 3216 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3217 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3218 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3219 * packet must fill in the Verification Tag field of the outbound 3220 * packet with the Verification Tag received in the SHUTDOWN ACK and 3221 * set the T-bit in the Chunk Flags to indicate that the Verification 3222 * Tag is reflected. 3223 * 3224 * 8) The receiver should respond to the sender of the OOTB packet with 3225 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3226 * MUST fill in the Verification Tag field of the outbound packet 3227 * with the value found in the Verification Tag field of the OOTB 3228 * packet and set the T-bit in the Chunk Flags to indicate that the 3229 * Verification Tag is reflected. After sending this ABORT, the 3230 * receiver of the OOTB packet shall discard the OOTB packet and take 3231 * no further action. 3232 */ 3233 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3234 const struct sctp_association *asoc, 3235 const sctp_subtype_t type, 3236 void *arg, 3237 sctp_cmd_seq_t *commands) 3238 { 3239 struct sctp_chunk *chunk = arg; 3240 struct sk_buff *skb = chunk->skb; 3241 sctp_chunkhdr_t *ch; 3242 __u8 *ch_end; 3243 int ootb_shut_ack = 0; 3244 3245 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3246 3247 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3248 do { 3249 /* Report violation if the chunk is less then minimal */ 3250 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3251 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3252 commands); 3253 3254 /* Now that we know we at least have a chunk header, 3255 * do things that are type appropriate. 3256 */ 3257 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3258 ootb_shut_ack = 1; 3259 3260 /* RFC 2960, Section 3.3.7 3261 * Moreover, under any circumstances, an endpoint that 3262 * receives an ABORT MUST NOT respond to that ABORT by 3263 * sending an ABORT of its own. 3264 */ 3265 if (SCTP_CID_ABORT == ch->type) 3266 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3267 3268 /* Report violation if chunk len overflows */ 3269 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3270 if (ch_end > skb_tail_pointer(skb)) 3271 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3272 commands); 3273 3274 ch = (sctp_chunkhdr_t *) ch_end; 3275 } while (ch_end < skb_tail_pointer(skb)); 3276 3277 if (ootb_shut_ack) 3278 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3279 else 3280 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3281 } 3282 3283 /* 3284 * Handle an "Out of the blue" SHUTDOWN ACK. 3285 * 3286 * Section: 8.4 5, sctpimpguide 2.41. 3287 * 3288 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3289 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3290 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3291 * packet must fill in the Verification Tag field of the outbound 3292 * packet with the Verification Tag received in the SHUTDOWN ACK and 3293 * set the T-bit in the Chunk Flags to indicate that the Verification 3294 * Tag is reflected. 3295 * 3296 * Inputs 3297 * (endpoint, asoc, type, arg, commands) 3298 * 3299 * Outputs 3300 * (sctp_disposition_t) 3301 * 3302 * The return value is the disposition of the chunk. 3303 */ 3304 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3305 const struct sctp_association *asoc, 3306 const sctp_subtype_t type, 3307 void *arg, 3308 sctp_cmd_seq_t *commands) 3309 { 3310 struct sctp_packet *packet = NULL; 3311 struct sctp_chunk *chunk = arg; 3312 struct sctp_chunk *shut; 3313 3314 packet = sctp_ootb_pkt_new(asoc, chunk); 3315 3316 if (packet) { 3317 /* Make an SHUTDOWN_COMPLETE. 3318 * The T bit will be set if the asoc is NULL. 3319 */ 3320 shut = sctp_make_shutdown_complete(asoc, chunk); 3321 if (!shut) { 3322 sctp_ootb_pkt_free(packet); 3323 return SCTP_DISPOSITION_NOMEM; 3324 } 3325 3326 /* Reflect vtag if T-Bit is set */ 3327 if (sctp_test_T_bit(shut)) 3328 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3329 3330 /* Set the skb to the belonging sock for accounting. */ 3331 shut->skb->sk = ep->base.sk; 3332 3333 sctp_packet_append_chunk(packet, shut); 3334 3335 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3336 SCTP_PACKET(packet)); 3337 3338 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3339 3340 /* If the chunk length is invalid, we don't want to process 3341 * the reset of the packet. 3342 */ 3343 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3344 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3345 3346 /* We need to discard the rest of the packet to prevent 3347 * potential bomming attacks from additional bundled chunks. 3348 * This is documented in SCTP Threats ID. 3349 */ 3350 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3351 } 3352 3353 return SCTP_DISPOSITION_NOMEM; 3354 } 3355 3356 /* 3357 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3358 * 3359 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3360 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3361 * procedures in section 8.4 SHOULD be followed, in other words it 3362 * should be treated as an Out Of The Blue packet. 3363 * [This means that we do NOT check the Verification Tag on these 3364 * chunks. --piggy ] 3365 * 3366 */ 3367 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3368 const struct sctp_association *asoc, 3369 const sctp_subtype_t type, 3370 void *arg, 3371 sctp_cmd_seq_t *commands) 3372 { 3373 struct sctp_chunk *chunk = arg; 3374 3375 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3376 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3377 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3378 commands); 3379 3380 /* Although we do have an association in this case, it corresponds 3381 * to a restarted association. So the packet is treated as an OOTB 3382 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3383 * called with a NULL association. 3384 */ 3385 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3386 3387 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3388 } 3389 3390 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3391 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3392 const struct sctp_association *asoc, 3393 const sctp_subtype_t type, void *arg, 3394 sctp_cmd_seq_t *commands) 3395 { 3396 struct sctp_chunk *chunk = arg; 3397 struct sctp_chunk *asconf_ack = NULL; 3398 struct sctp_paramhdr *err_param = NULL; 3399 sctp_addiphdr_t *hdr; 3400 union sctp_addr_param *addr_param; 3401 __u32 serial; 3402 int length; 3403 3404 if (!sctp_vtag_verify(chunk, asoc)) { 3405 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3406 SCTP_NULL()); 3407 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3408 } 3409 3410 /* ADD-IP: Section 4.1.1 3411 * This chunk MUST be sent in an authenticated way by using 3412 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3413 * is received unauthenticated it MUST be silently discarded as 3414 * described in [I-D.ietf-tsvwg-sctp-auth]. 3415 */ 3416 if (!sctp_addip_noauth && !chunk->auth) 3417 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3418 3419 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3420 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3421 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3422 commands); 3423 3424 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3425 serial = ntohl(hdr->serial); 3426 3427 addr_param = (union sctp_addr_param *)hdr->params; 3428 length = ntohs(addr_param->p.length); 3429 if (length < sizeof(sctp_paramhdr_t)) 3430 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3431 (void *)addr_param, commands); 3432 3433 /* Verify the ASCONF chunk before processing it. */ 3434 if (!sctp_verify_asconf(asoc, 3435 (sctp_paramhdr_t *)((void *)addr_param + length), 3436 (void *)chunk->chunk_end, 3437 &err_param)) 3438 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3439 (void *)err_param, commands); 3440 3441 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3442 * the endpoint stored in a new association variable 3443 * 'Peer-Serial-Number'. 3444 */ 3445 if (serial == asoc->peer.addip_serial + 1) { 3446 /* If this is the first instance of ASCONF in the packet, 3447 * we can clean our old ASCONF-ACKs. 3448 */ 3449 if (!chunk->has_asconf) 3450 sctp_assoc_clean_asconf_ack_cache(asoc); 3451 3452 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3453 * expected, process the ASCONF as described below and after 3454 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3455 * the response packet and cache a copy of it (in the event it 3456 * later needs to be retransmitted). 3457 * 3458 * Essentially, do V1-V5. 3459 */ 3460 asconf_ack = sctp_process_asconf((struct sctp_association *) 3461 asoc, chunk); 3462 if (!asconf_ack) 3463 return SCTP_DISPOSITION_NOMEM; 3464 } else if (serial < asoc->peer.addip_serial + 1) { 3465 /* ADDIP 5.2 E2) 3466 * If the value found in the Sequence Number is less than the 3467 * ('Peer- Sequence-Number' + 1), simply skip to the next 3468 * ASCONF, and include in the outbound response packet 3469 * any previously cached ASCONF-ACK response that was 3470 * sent and saved that matches the Sequence Number of the 3471 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3472 * Chunk exists. This will occur when an older ASCONF 3473 * arrives out of order. In such a case, the receiver 3474 * should skip the ASCONF Chunk and not include ASCONF-ACK 3475 * Chunk for that chunk. 3476 */ 3477 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3478 if (!asconf_ack) 3479 return SCTP_DISPOSITION_DISCARD; 3480 } else { 3481 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3482 * it must be either a stale packet or from an attacker. 3483 */ 3484 return SCTP_DISPOSITION_DISCARD; 3485 } 3486 3487 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3488 * containing the ASCONF-ACK Chunks MUST be the source address of 3489 * the SCTP packet that held the ASCONF Chunks. 3490 * 3491 * To do this properly, we'll set the destination address of the chunk 3492 * and at the transmit time, will try look up the transport to use. 3493 * Since ASCONFs may be bundled, the correct transport may not be 3494 * created untill we process the entire packet, thus this workaround. 3495 */ 3496 asconf_ack->dest = chunk->source; 3497 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3498 3499 return SCTP_DISPOSITION_CONSUME; 3500 } 3501 3502 /* 3503 * ADDIP Section 4.3 General rules for address manipulation 3504 * When building TLV parameters for the ASCONF Chunk that will add or 3505 * delete IP addresses the D0 to D13 rules should be applied: 3506 */ 3507 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3508 const struct sctp_association *asoc, 3509 const sctp_subtype_t type, void *arg, 3510 sctp_cmd_seq_t *commands) 3511 { 3512 struct sctp_chunk *asconf_ack = arg; 3513 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3514 struct sctp_chunk *abort; 3515 struct sctp_paramhdr *err_param = NULL; 3516 sctp_addiphdr_t *addip_hdr; 3517 __u32 sent_serial, rcvd_serial; 3518 3519 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3520 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3521 SCTP_NULL()); 3522 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3523 } 3524 3525 /* ADD-IP, Section 4.1.2: 3526 * This chunk MUST be sent in an authenticated way by using 3527 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3528 * is received unauthenticated it MUST be silently discarded as 3529 * described in [I-D.ietf-tsvwg-sctp-auth]. 3530 */ 3531 if (!sctp_addip_noauth && !asconf_ack->auth) 3532 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3533 3534 /* Make sure that the ADDIP chunk has a valid length. */ 3535 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3536 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3537 commands); 3538 3539 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3540 rcvd_serial = ntohl(addip_hdr->serial); 3541 3542 /* Verify the ASCONF-ACK chunk before processing it. */ 3543 if (!sctp_verify_asconf(asoc, 3544 (sctp_paramhdr_t *)addip_hdr->params, 3545 (void *)asconf_ack->chunk_end, 3546 &err_param)) 3547 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3548 (void *)err_param, commands); 3549 3550 if (last_asconf) { 3551 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3552 sent_serial = ntohl(addip_hdr->serial); 3553 } else { 3554 sent_serial = asoc->addip_serial - 1; 3555 } 3556 3557 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3558 * equal to the next serial number to be used but no ASCONF chunk is 3559 * outstanding the endpoint MUST ABORT the association. Note that a 3560 * sequence number is greater than if it is no more than 2^^31-1 3561 * larger than the current sequence number (using serial arithmetic). 3562 */ 3563 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3564 !(asoc->addip_last_asconf)) { 3565 abort = sctp_make_abort(asoc, asconf_ack, 3566 sizeof(sctp_errhdr_t)); 3567 if (abort) { 3568 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3569 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3570 SCTP_CHUNK(abort)); 3571 } 3572 /* We are going to ABORT, so we might as well stop 3573 * processing the rest of the chunks in the packet. 3574 */ 3575 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3576 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3577 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3578 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3579 SCTP_ERROR(ECONNABORTED)); 3580 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3581 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3582 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3583 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3584 return SCTP_DISPOSITION_ABORT; 3585 } 3586 3587 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3588 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3589 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3590 3591 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3592 asconf_ack)) 3593 return SCTP_DISPOSITION_CONSUME; 3594 3595 abort = sctp_make_abort(asoc, asconf_ack, 3596 sizeof(sctp_errhdr_t)); 3597 if (abort) { 3598 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3599 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3600 SCTP_CHUNK(abort)); 3601 } 3602 /* We are going to ABORT, so we might as well stop 3603 * processing the rest of the chunks in the packet. 3604 */ 3605 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3606 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3607 SCTP_ERROR(ECONNABORTED)); 3608 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3609 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3610 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3611 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3612 return SCTP_DISPOSITION_ABORT; 3613 } 3614 3615 return SCTP_DISPOSITION_DISCARD; 3616 } 3617 3618 /* 3619 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3620 * 3621 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3622 * its cumulative TSN point to the value carried in the FORWARD TSN 3623 * chunk, and then MUST further advance its cumulative TSN point locally 3624 * if possible. 3625 * After the above processing, the data receiver MUST stop reporting any 3626 * missing TSNs earlier than or equal to the new cumulative TSN point. 3627 * 3628 * Verification Tag: 8.5 Verification Tag [Normal verification] 3629 * 3630 * The return value is the disposition of the chunk. 3631 */ 3632 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3633 const struct sctp_association *asoc, 3634 const sctp_subtype_t type, 3635 void *arg, 3636 sctp_cmd_seq_t *commands) 3637 { 3638 struct sctp_chunk *chunk = arg; 3639 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3640 __u16 len; 3641 __u32 tsn; 3642 3643 if (!sctp_vtag_verify(chunk, asoc)) { 3644 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3645 SCTP_NULL()); 3646 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3647 } 3648 3649 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3650 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3651 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3652 commands); 3653 3654 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3655 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3656 len = ntohs(chunk->chunk_hdr->length); 3657 len -= sizeof(struct sctp_chunkhdr); 3658 skb_pull(chunk->skb, len); 3659 3660 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3661 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3662 3663 /* The TSN is too high--silently discard the chunk and count on it 3664 * getting retransmitted later. 3665 */ 3666 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3667 goto discard_noforce; 3668 3669 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3670 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3671 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3672 SCTP_CHUNK(chunk)); 3673 3674 /* Count this as receiving DATA. */ 3675 if (asoc->autoclose) { 3676 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3677 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3678 } 3679 3680 /* FIXME: For now send a SACK, but DATA processing may 3681 * send another. 3682 */ 3683 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3684 3685 return SCTP_DISPOSITION_CONSUME; 3686 3687 discard_noforce: 3688 return SCTP_DISPOSITION_DISCARD; 3689 } 3690 3691 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3692 const struct sctp_endpoint *ep, 3693 const struct sctp_association *asoc, 3694 const sctp_subtype_t type, 3695 void *arg, 3696 sctp_cmd_seq_t *commands) 3697 { 3698 struct sctp_chunk *chunk = arg; 3699 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3700 __u16 len; 3701 __u32 tsn; 3702 3703 if (!sctp_vtag_verify(chunk, asoc)) { 3704 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3705 SCTP_NULL()); 3706 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3707 } 3708 3709 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3710 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3711 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3712 commands); 3713 3714 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3715 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3716 len = ntohs(chunk->chunk_hdr->length); 3717 len -= sizeof(struct sctp_chunkhdr); 3718 skb_pull(chunk->skb, len); 3719 3720 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3721 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3722 3723 /* The TSN is too high--silently discard the chunk and count on it 3724 * getting retransmitted later. 3725 */ 3726 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3727 goto gen_shutdown; 3728 3729 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3730 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3731 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3732 SCTP_CHUNK(chunk)); 3733 3734 /* Go a head and force a SACK, since we are shutting down. */ 3735 gen_shutdown: 3736 /* Implementor's Guide. 3737 * 3738 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3739 * respond to each received packet containing one or more DATA chunk(s) 3740 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3741 */ 3742 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3743 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3744 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3745 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3746 3747 return SCTP_DISPOSITION_CONSUME; 3748 } 3749 3750 /* 3751 * SCTP-AUTH Section 6.3 Receving authenticated chukns 3752 * 3753 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3754 * Identifier field. If this algorithm was not specified by the 3755 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3756 * during association setup, the AUTH chunk and all chunks after it MUST 3757 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3758 * defined in Section 4.1. 3759 * 3760 * If an endpoint with no shared key receives a Shared Key Identifier 3761 * other than 0, it MUST silently discard all authenticated chunks. If 3762 * the endpoint has at least one endpoint pair shared key for the peer, 3763 * it MUST use the key specified by the Shared Key Identifier if a 3764 * key has been configured for that Shared Key Identifier. If no 3765 * endpoint pair shared key has been configured for that Shared Key 3766 * Identifier, all authenticated chunks MUST be silently discarded. 3767 * 3768 * Verification Tag: 8.5 Verification Tag [Normal verification] 3769 * 3770 * The return value is the disposition of the chunk. 3771 */ 3772 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 3773 const struct sctp_association *asoc, 3774 const sctp_subtype_t type, 3775 struct sctp_chunk *chunk) 3776 { 3777 struct sctp_authhdr *auth_hdr; 3778 struct sctp_hmac *hmac; 3779 unsigned int sig_len; 3780 __u16 key_id; 3781 __u8 *save_digest; 3782 __u8 *digest; 3783 3784 /* Pull in the auth header, so we can do some more verification */ 3785 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3786 chunk->subh.auth_hdr = auth_hdr; 3787 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3788 3789 /* Make sure that we suport the HMAC algorithm from the auth 3790 * chunk. 3791 */ 3792 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 3793 return SCTP_IERROR_AUTH_BAD_HMAC; 3794 3795 /* Make sure that the provided shared key identifier has been 3796 * configured 3797 */ 3798 key_id = ntohs(auth_hdr->shkey_id); 3799 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 3800 return SCTP_IERROR_AUTH_BAD_KEYID; 3801 3802 3803 /* Make sure that the length of the signature matches what 3804 * we expect. 3805 */ 3806 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 3807 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 3808 if (sig_len != hmac->hmac_len) 3809 return SCTP_IERROR_PROTO_VIOLATION; 3810 3811 /* Now that we've done validation checks, we can compute and 3812 * verify the hmac. The steps involved are: 3813 * 1. Save the digest from the chunk. 3814 * 2. Zero out the digest in the chunk. 3815 * 3. Compute the new digest 3816 * 4. Compare saved and new digests. 3817 */ 3818 digest = auth_hdr->hmac; 3819 skb_pull(chunk->skb, sig_len); 3820 3821 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 3822 if (!save_digest) 3823 goto nomem; 3824 3825 memset(digest, 0, sig_len); 3826 3827 sctp_auth_calculate_hmac(asoc, chunk->skb, 3828 (struct sctp_auth_chunk *)chunk->chunk_hdr, 3829 GFP_ATOMIC); 3830 3831 /* Discard the packet if the digests do not match */ 3832 if (memcmp(save_digest, digest, sig_len)) { 3833 kfree(save_digest); 3834 return SCTP_IERROR_BAD_SIG; 3835 } 3836 3837 kfree(save_digest); 3838 chunk->auth = 1; 3839 3840 return SCTP_IERROR_NO_ERROR; 3841 nomem: 3842 return SCTP_IERROR_NOMEM; 3843 } 3844 3845 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep, 3846 const struct sctp_association *asoc, 3847 const sctp_subtype_t type, 3848 void *arg, 3849 sctp_cmd_seq_t *commands) 3850 { 3851 struct sctp_authhdr *auth_hdr; 3852 struct sctp_chunk *chunk = arg; 3853 struct sctp_chunk *err_chunk; 3854 sctp_ierror_t error; 3855 3856 /* Make sure that the peer has AUTH capable */ 3857 if (!asoc->peer.auth_capable) 3858 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands); 3859 3860 if (!sctp_vtag_verify(chunk, asoc)) { 3861 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3862 SCTP_NULL()); 3863 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3864 } 3865 3866 /* Make sure that the AUTH chunk has valid length. */ 3867 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 3868 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3869 commands); 3870 3871 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3872 error = sctp_sf_authenticate(ep, asoc, type, chunk); 3873 switch (error) { 3874 case SCTP_IERROR_AUTH_BAD_HMAC: 3875 /* Generate the ERROR chunk and discard the rest 3876 * of the packet 3877 */ 3878 err_chunk = sctp_make_op_error(asoc, chunk, 3879 SCTP_ERROR_UNSUP_HMAC, 3880 &auth_hdr->hmac_id, 3881 sizeof(__u16)); 3882 if (err_chunk) { 3883 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3884 SCTP_CHUNK(err_chunk)); 3885 } 3886 /* Fall Through */ 3887 case SCTP_IERROR_AUTH_BAD_KEYID: 3888 case SCTP_IERROR_BAD_SIG: 3889 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3890 break; 3891 case SCTP_IERROR_PROTO_VIOLATION: 3892 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3893 commands); 3894 break; 3895 case SCTP_IERROR_NOMEM: 3896 return SCTP_DISPOSITION_NOMEM; 3897 default: 3898 break; 3899 } 3900 3901 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 3902 struct sctp_ulpevent *ev; 3903 3904 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 3905 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 3906 3907 if (!ev) 3908 return -ENOMEM; 3909 3910 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3911 SCTP_ULPEVENT(ev)); 3912 } 3913 3914 return SCTP_DISPOSITION_CONSUME; 3915 } 3916 3917 /* 3918 * Process an unknown chunk. 3919 * 3920 * Section: 3.2. Also, 2.1 in the implementor's guide. 3921 * 3922 * Chunk Types are encoded such that the highest-order two bits specify 3923 * the action that must be taken if the processing endpoint does not 3924 * recognize the Chunk Type. 3925 * 3926 * 00 - Stop processing this SCTP packet and discard it, do not process 3927 * any further chunks within it. 3928 * 3929 * 01 - Stop processing this SCTP packet and discard it, do not process 3930 * any further chunks within it, and report the unrecognized 3931 * chunk in an 'Unrecognized Chunk Type'. 3932 * 3933 * 10 - Skip this chunk and continue processing. 3934 * 3935 * 11 - Skip this chunk and continue processing, but report in an ERROR 3936 * Chunk using the 'Unrecognized Chunk Type' cause of error. 3937 * 3938 * The return value is the disposition of the chunk. 3939 */ 3940 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 3941 const struct sctp_association *asoc, 3942 const sctp_subtype_t type, 3943 void *arg, 3944 sctp_cmd_seq_t *commands) 3945 { 3946 struct sctp_chunk *unk_chunk = arg; 3947 struct sctp_chunk *err_chunk; 3948 sctp_chunkhdr_t *hdr; 3949 3950 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 3951 3952 if (!sctp_vtag_verify(unk_chunk, asoc)) 3953 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3954 3955 /* Make sure that the chunk has a valid length. 3956 * Since we don't know the chunk type, we use a general 3957 * chunkhdr structure to make a comparison. 3958 */ 3959 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 3960 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3961 commands); 3962 3963 switch (type.chunk & SCTP_CID_ACTION_MASK) { 3964 case SCTP_CID_ACTION_DISCARD: 3965 /* Discard the packet. */ 3966 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3967 break; 3968 case SCTP_CID_ACTION_DISCARD_ERR: 3969 /* Generate an ERROR chunk as response. */ 3970 hdr = unk_chunk->chunk_hdr; 3971 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3972 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3973 WORD_ROUND(ntohs(hdr->length))); 3974 if (err_chunk) { 3975 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3976 SCTP_CHUNK(err_chunk)); 3977 } 3978 3979 /* Discard the packet. */ 3980 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3981 return SCTP_DISPOSITION_CONSUME; 3982 break; 3983 case SCTP_CID_ACTION_SKIP: 3984 /* Skip the chunk. */ 3985 return SCTP_DISPOSITION_DISCARD; 3986 break; 3987 case SCTP_CID_ACTION_SKIP_ERR: 3988 /* Generate an ERROR chunk as response. */ 3989 hdr = unk_chunk->chunk_hdr; 3990 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3991 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3992 WORD_ROUND(ntohs(hdr->length))); 3993 if (err_chunk) { 3994 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3995 SCTP_CHUNK(err_chunk)); 3996 } 3997 /* Skip the chunk. */ 3998 return SCTP_DISPOSITION_CONSUME; 3999 break; 4000 default: 4001 break; 4002 } 4003 4004 return SCTP_DISPOSITION_DISCARD; 4005 } 4006 4007 /* 4008 * Discard the chunk. 4009 * 4010 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4011 * [Too numerous to mention...] 4012 * Verification Tag: No verification needed. 4013 * Inputs 4014 * (endpoint, asoc, chunk) 4015 * 4016 * Outputs 4017 * (asoc, reply_msg, msg_up, timers, counters) 4018 * 4019 * The return value is the disposition of the chunk. 4020 */ 4021 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 4022 const struct sctp_association *asoc, 4023 const sctp_subtype_t type, 4024 void *arg, 4025 sctp_cmd_seq_t *commands) 4026 { 4027 struct sctp_chunk *chunk = arg; 4028 4029 /* Make sure that the chunk has a valid length. 4030 * Since we don't know the chunk type, we use a general 4031 * chunkhdr structure to make a comparison. 4032 */ 4033 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4034 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4035 commands); 4036 4037 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 4038 return SCTP_DISPOSITION_DISCARD; 4039 } 4040 4041 /* 4042 * Discard the whole packet. 4043 * 4044 * Section: 8.4 2) 4045 * 4046 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4047 * silently discard the OOTB packet and take no further action. 4048 * 4049 * Verification Tag: No verification necessary 4050 * 4051 * Inputs 4052 * (endpoint, asoc, chunk) 4053 * 4054 * Outputs 4055 * (asoc, reply_msg, msg_up, timers, counters) 4056 * 4057 * The return value is the disposition of the chunk. 4058 */ 4059 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 4060 const struct sctp_association *asoc, 4061 const sctp_subtype_t type, 4062 void *arg, 4063 sctp_cmd_seq_t *commands) 4064 { 4065 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS); 4066 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4067 4068 return SCTP_DISPOSITION_CONSUME; 4069 } 4070 4071 4072 /* 4073 * The other end is violating protocol. 4074 * 4075 * Section: Not specified 4076 * Verification Tag: Not specified 4077 * Inputs 4078 * (endpoint, asoc, chunk) 4079 * 4080 * Outputs 4081 * (asoc, reply_msg, msg_up, timers, counters) 4082 * 4083 * We simply tag the chunk as a violation. The state machine will log 4084 * the violation and continue. 4085 */ 4086 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 4087 const struct sctp_association *asoc, 4088 const sctp_subtype_t type, 4089 void *arg, 4090 sctp_cmd_seq_t *commands) 4091 { 4092 struct sctp_chunk *chunk = arg; 4093 4094 /* Make sure that the chunk has a valid length. */ 4095 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4096 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4097 commands); 4098 4099 return SCTP_DISPOSITION_VIOLATION; 4100 } 4101 4102 /* 4103 * Common function to handle a protocol violation. 4104 */ 4105 static sctp_disposition_t sctp_sf_abort_violation( 4106 const struct sctp_endpoint *ep, 4107 const struct sctp_association *asoc, 4108 void *arg, 4109 sctp_cmd_seq_t *commands, 4110 const __u8 *payload, 4111 const size_t paylen) 4112 { 4113 struct sctp_packet *packet = NULL; 4114 struct sctp_chunk *chunk = arg; 4115 struct sctp_chunk *abort = NULL; 4116 4117 /* SCTP-AUTH, Section 6.3: 4118 * It should be noted that if the receiver wants to tear 4119 * down an association in an authenticated way only, the 4120 * handling of malformed packets should not result in 4121 * tearing down the association. 4122 * 4123 * This means that if we only want to abort associations 4124 * in an authenticated way (i.e AUTH+ABORT), then we 4125 * can't destroy this association just becuase the packet 4126 * was malformed. 4127 */ 4128 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4129 goto discard; 4130 4131 /* Make the abort chunk. */ 4132 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4133 if (!abort) 4134 goto nomem; 4135 4136 if (asoc) { 4137 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4138 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4139 !asoc->peer.i.init_tag) { 4140 sctp_initack_chunk_t *initack; 4141 4142 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4143 if (!sctp_chunk_length_valid(chunk, 4144 sizeof(sctp_initack_chunk_t))) 4145 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4146 else { 4147 unsigned int inittag; 4148 4149 inittag = ntohl(initack->init_hdr.init_tag); 4150 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4151 SCTP_U32(inittag)); 4152 } 4153 } 4154 4155 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4156 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4157 4158 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4159 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4160 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4161 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4162 SCTP_ERROR(ECONNREFUSED)); 4163 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4164 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4165 } else { 4166 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4167 SCTP_ERROR(ECONNABORTED)); 4168 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4169 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4170 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4171 } 4172 } else { 4173 packet = sctp_ootb_pkt_new(asoc, chunk); 4174 4175 if (!packet) 4176 goto nomem_pkt; 4177 4178 if (sctp_test_T_bit(abort)) 4179 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4180 4181 abort->skb->sk = ep->base.sk; 4182 4183 sctp_packet_append_chunk(packet, abort); 4184 4185 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4186 SCTP_PACKET(packet)); 4187 4188 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4189 } 4190 4191 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4192 4193 discard: 4194 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4195 return SCTP_DISPOSITION_ABORT; 4196 4197 nomem_pkt: 4198 sctp_chunk_free(abort); 4199 nomem: 4200 return SCTP_DISPOSITION_NOMEM; 4201 } 4202 4203 /* 4204 * Handle a protocol violation when the chunk length is invalid. 4205 * "Invalid" length is identified as smaller then the minimal length a 4206 * given chunk can be. For example, a SACK chunk has invalid length 4207 * if it's length is set to be smaller then the size of sctp_sack_chunk_t. 4208 * 4209 * We inform the other end by sending an ABORT with a Protocol Violation 4210 * error code. 4211 * 4212 * Section: Not specified 4213 * Verification Tag: Nothing to do 4214 * Inputs 4215 * (endpoint, asoc, chunk) 4216 * 4217 * Outputs 4218 * (reply_msg, msg_up, counters) 4219 * 4220 * Generate an ABORT chunk and terminate the association. 4221 */ 4222 static sctp_disposition_t sctp_sf_violation_chunklen( 4223 const struct sctp_endpoint *ep, 4224 const struct sctp_association *asoc, 4225 const sctp_subtype_t type, 4226 void *arg, 4227 sctp_cmd_seq_t *commands) 4228 { 4229 static const char err_str[]="The following chunk had invalid length:"; 4230 4231 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4232 sizeof(err_str)); 4233 } 4234 4235 /* 4236 * Handle a protocol violation when the parameter length is invalid. 4237 * "Invalid" length is identified as smaller then the minimal length a 4238 * given parameter can be. 4239 */ 4240 static sctp_disposition_t sctp_sf_violation_paramlen( 4241 const struct sctp_endpoint *ep, 4242 const struct sctp_association *asoc, 4243 const sctp_subtype_t type, 4244 void *arg, void *ext, 4245 sctp_cmd_seq_t *commands) 4246 { 4247 struct sctp_chunk *chunk = arg; 4248 struct sctp_paramhdr *param = ext; 4249 struct sctp_chunk *abort = NULL; 4250 4251 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4252 goto discard; 4253 4254 /* Make the abort chunk. */ 4255 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4256 if (!abort) 4257 goto nomem; 4258 4259 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4260 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4261 4262 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4263 SCTP_ERROR(ECONNABORTED)); 4264 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4265 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4266 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4267 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4268 4269 discard: 4270 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4271 return SCTP_DISPOSITION_ABORT; 4272 nomem: 4273 return SCTP_DISPOSITION_NOMEM; 4274 } 4275 4276 /* Handle a protocol violation when the peer trying to advance the 4277 * cumulative tsn ack to a point beyond the max tsn currently sent. 4278 * 4279 * We inform the other end by sending an ABORT with a Protocol Violation 4280 * error code. 4281 */ 4282 static sctp_disposition_t sctp_sf_violation_ctsn( 4283 const struct sctp_endpoint *ep, 4284 const struct sctp_association *asoc, 4285 const sctp_subtype_t type, 4286 void *arg, 4287 sctp_cmd_seq_t *commands) 4288 { 4289 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4290 4291 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4292 sizeof(err_str)); 4293 } 4294 4295 /* Handle protocol violation of an invalid chunk bundling. For example, 4296 * when we have an association and we recieve bundled INIT-ACK, or 4297 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4298 * statement from the specs. Additinally, there might be an attacker 4299 * on the path and we may not want to continue this communication. 4300 */ 4301 static sctp_disposition_t sctp_sf_violation_chunk( 4302 const struct sctp_endpoint *ep, 4303 const struct sctp_association *asoc, 4304 const sctp_subtype_t type, 4305 void *arg, 4306 sctp_cmd_seq_t *commands) 4307 { 4308 static const char err_str[]="The following chunk violates protocol:"; 4309 4310 if (!asoc) 4311 return sctp_sf_violation(ep, asoc, type, arg, commands); 4312 4313 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4314 sizeof(err_str)); 4315 } 4316 /*************************************************************************** 4317 * These are the state functions for handling primitive (Section 10) events. 4318 ***************************************************************************/ 4319 /* 4320 * sctp_sf_do_prm_asoc 4321 * 4322 * Section: 10.1 ULP-to-SCTP 4323 * B) Associate 4324 * 4325 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4326 * outbound stream count) 4327 * -> association id [,destination transport addr list] [,outbound stream 4328 * count] 4329 * 4330 * This primitive allows the upper layer to initiate an association to a 4331 * specific peer endpoint. 4332 * 4333 * The peer endpoint shall be specified by one of the transport addresses 4334 * which defines the endpoint (see Section 1.4). If the local SCTP 4335 * instance has not been initialized, the ASSOCIATE is considered an 4336 * error. 4337 * [This is not relevant for the kernel implementation since we do all 4338 * initialization at boot time. It we hadn't initialized we wouldn't 4339 * get anywhere near this code.] 4340 * 4341 * An association id, which is a local handle to the SCTP association, 4342 * will be returned on successful establishment of the association. If 4343 * SCTP is not able to open an SCTP association with the peer endpoint, 4344 * an error is returned. 4345 * [In the kernel implementation, the struct sctp_association needs to 4346 * be created BEFORE causing this primitive to run.] 4347 * 4348 * Other association parameters may be returned, including the 4349 * complete destination transport addresses of the peer as well as the 4350 * outbound stream count of the local endpoint. One of the transport 4351 * address from the returned destination addresses will be selected by 4352 * the local endpoint as default primary path for sending SCTP packets 4353 * to this peer. The returned "destination transport addr list" can 4354 * be used by the ULP to change the default primary path or to force 4355 * sending a packet to a specific transport address. [All of this 4356 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4357 * function.] 4358 * 4359 * Mandatory attributes: 4360 * 4361 * o local SCTP instance name - obtained from the INITIALIZE operation. 4362 * [This is the argument asoc.] 4363 * o destination transport addr - specified as one of the transport 4364 * addresses of the peer endpoint with which the association is to be 4365 * established. 4366 * [This is asoc->peer.active_path.] 4367 * o outbound stream count - the number of outbound streams the ULP 4368 * would like to open towards this peer endpoint. 4369 * [BUG: This is not currently implemented.] 4370 * Optional attributes: 4371 * 4372 * None. 4373 * 4374 * The return value is a disposition. 4375 */ 4376 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 4377 const struct sctp_association *asoc, 4378 const sctp_subtype_t type, 4379 void *arg, 4380 sctp_cmd_seq_t *commands) 4381 { 4382 struct sctp_chunk *repl; 4383 struct sctp_association* my_asoc; 4384 4385 /* The comment below says that we enter COOKIE-WAIT AFTER 4386 * sending the INIT, but that doesn't actually work in our 4387 * implementation... 4388 */ 4389 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4390 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4391 4392 /* RFC 2960 5.1 Normal Establishment of an Association 4393 * 4394 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4395 * must provide its Verification Tag (Tag_A) in the Initiate 4396 * Tag field. Tag_A SHOULD be a random number in the range of 4397 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4398 */ 4399 4400 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4401 if (!repl) 4402 goto nomem; 4403 4404 /* Cast away the const modifier, as we want to just 4405 * rerun it through as a sideffect. 4406 */ 4407 my_asoc = (struct sctp_association *)asoc; 4408 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4409 4410 /* Choose transport for INIT. */ 4411 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4412 SCTP_CHUNK(repl)); 4413 4414 /* After sending the INIT, "A" starts the T1-init timer and 4415 * enters the COOKIE-WAIT state. 4416 */ 4417 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4418 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4419 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4420 return SCTP_DISPOSITION_CONSUME; 4421 4422 nomem: 4423 return SCTP_DISPOSITION_NOMEM; 4424 } 4425 4426 /* 4427 * Process the SEND primitive. 4428 * 4429 * Section: 10.1 ULP-to-SCTP 4430 * E) Send 4431 * 4432 * Format: SEND(association id, buffer address, byte count [,context] 4433 * [,stream id] [,life time] [,destination transport address] 4434 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4435 * -> result 4436 * 4437 * This is the main method to send user data via SCTP. 4438 * 4439 * Mandatory attributes: 4440 * 4441 * o association id - local handle to the SCTP association 4442 * 4443 * o buffer address - the location where the user message to be 4444 * transmitted is stored; 4445 * 4446 * o byte count - The size of the user data in number of bytes; 4447 * 4448 * Optional attributes: 4449 * 4450 * o context - an optional 32 bit integer that will be carried in the 4451 * sending failure notification to the ULP if the transportation of 4452 * this User Message fails. 4453 * 4454 * o stream id - to indicate which stream to send the data on. If not 4455 * specified, stream 0 will be used. 4456 * 4457 * o life time - specifies the life time of the user data. The user data 4458 * will not be sent by SCTP after the life time expires. This 4459 * parameter can be used to avoid efforts to transmit stale 4460 * user messages. SCTP notifies the ULP if the data cannot be 4461 * initiated to transport (i.e. sent to the destination via SCTP's 4462 * send primitive) within the life time variable. However, the 4463 * user data will be transmitted if SCTP has attempted to transmit a 4464 * chunk before the life time expired. 4465 * 4466 * o destination transport address - specified as one of the destination 4467 * transport addresses of the peer endpoint to which this packet 4468 * should be sent. Whenever possible, SCTP should use this destination 4469 * transport address for sending the packets, instead of the current 4470 * primary path. 4471 * 4472 * o unorder flag - this flag, if present, indicates that the user 4473 * would like the data delivered in an unordered fashion to the peer 4474 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4475 * message). 4476 * 4477 * o no-bundle flag - instructs SCTP not to bundle this user data with 4478 * other outbound DATA chunks. SCTP MAY still bundle even when 4479 * this flag is present, when faced with network congestion. 4480 * 4481 * o payload protocol-id - A 32 bit unsigned integer that is to be 4482 * passed to the peer indicating the type of payload protocol data 4483 * being transmitted. This value is passed as opaque data by SCTP. 4484 * 4485 * The return value is the disposition. 4486 */ 4487 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 4488 const struct sctp_association *asoc, 4489 const sctp_subtype_t type, 4490 void *arg, 4491 sctp_cmd_seq_t *commands) 4492 { 4493 struct sctp_chunk *chunk = arg; 4494 4495 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4496 return SCTP_DISPOSITION_CONSUME; 4497 } 4498 4499 /* 4500 * Process the SHUTDOWN primitive. 4501 * 4502 * Section: 10.1: 4503 * C) Shutdown 4504 * 4505 * Format: SHUTDOWN(association id) 4506 * -> result 4507 * 4508 * Gracefully closes an association. Any locally queued user data 4509 * will be delivered to the peer. The association will be terminated only 4510 * after the peer acknowledges all the SCTP packets sent. A success code 4511 * will be returned on successful termination of the association. If 4512 * attempting to terminate the association results in a failure, an error 4513 * code shall be returned. 4514 * 4515 * Mandatory attributes: 4516 * 4517 * o association id - local handle to the SCTP association 4518 * 4519 * Optional attributes: 4520 * 4521 * None. 4522 * 4523 * The return value is the disposition. 4524 */ 4525 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4526 const struct sctp_endpoint *ep, 4527 const struct sctp_association *asoc, 4528 const sctp_subtype_t type, 4529 void *arg, 4530 sctp_cmd_seq_t *commands) 4531 { 4532 int disposition; 4533 4534 /* From 9.2 Shutdown of an Association 4535 * Upon receipt of the SHUTDOWN primitive from its upper 4536 * layer, the endpoint enters SHUTDOWN-PENDING state and 4537 * remains there until all outstanding data has been 4538 * acknowledged by its peer. The endpoint accepts no new data 4539 * from its upper layer, but retransmits data to the far end 4540 * if necessary to fill gaps. 4541 */ 4542 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4543 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4544 4545 disposition = SCTP_DISPOSITION_CONSUME; 4546 if (sctp_outq_is_empty(&asoc->outqueue)) { 4547 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4548 arg, commands); 4549 } 4550 return disposition; 4551 } 4552 4553 /* 4554 * Process the ABORT primitive. 4555 * 4556 * Section: 10.1: 4557 * C) Abort 4558 * 4559 * Format: Abort(association id [, cause code]) 4560 * -> result 4561 * 4562 * Ungracefully closes an association. Any locally queued user data 4563 * will be discarded and an ABORT chunk is sent to the peer. A success code 4564 * will be returned on successful abortion of the association. If 4565 * attempting to abort the association results in a failure, an error 4566 * code shall be returned. 4567 * 4568 * Mandatory attributes: 4569 * 4570 * o association id - local handle to the SCTP association 4571 * 4572 * Optional attributes: 4573 * 4574 * o cause code - reason of the abort to be passed to the peer 4575 * 4576 * None. 4577 * 4578 * The return value is the disposition. 4579 */ 4580 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4581 const struct sctp_endpoint *ep, 4582 const struct sctp_association *asoc, 4583 const sctp_subtype_t type, 4584 void *arg, 4585 sctp_cmd_seq_t *commands) 4586 { 4587 /* From 9.1 Abort of an Association 4588 * Upon receipt of the ABORT primitive from its upper 4589 * layer, the endpoint enters CLOSED state and 4590 * discard all outstanding data has been 4591 * acknowledged by its peer. The endpoint accepts no new data 4592 * from its upper layer, but retransmits data to the far end 4593 * if necessary to fill gaps. 4594 */ 4595 struct sctp_chunk *abort = arg; 4596 sctp_disposition_t retval; 4597 4598 retval = SCTP_DISPOSITION_CONSUME; 4599 4600 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4601 4602 /* Even if we can't send the ABORT due to low memory delete the 4603 * TCB. This is a departure from our typical NOMEM handling. 4604 */ 4605 4606 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4607 SCTP_ERROR(ECONNABORTED)); 4608 /* Delete the established association. */ 4609 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4610 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4611 4612 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4613 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4614 4615 return retval; 4616 } 4617 4618 /* We tried an illegal operation on an association which is closed. */ 4619 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4620 const struct sctp_association *asoc, 4621 const sctp_subtype_t type, 4622 void *arg, 4623 sctp_cmd_seq_t *commands) 4624 { 4625 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4626 return SCTP_DISPOSITION_CONSUME; 4627 } 4628 4629 /* We tried an illegal operation on an association which is shutting 4630 * down. 4631 */ 4632 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4633 const struct sctp_association *asoc, 4634 const sctp_subtype_t type, 4635 void *arg, 4636 sctp_cmd_seq_t *commands) 4637 { 4638 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4639 SCTP_ERROR(-ESHUTDOWN)); 4640 return SCTP_DISPOSITION_CONSUME; 4641 } 4642 4643 /* 4644 * sctp_cookie_wait_prm_shutdown 4645 * 4646 * Section: 4 Note: 2 4647 * Verification Tag: 4648 * Inputs 4649 * (endpoint, asoc) 4650 * 4651 * The RFC does not explicitly address this issue, but is the route through the 4652 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4653 * 4654 * Outputs 4655 * (timers) 4656 */ 4657 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4658 const struct sctp_endpoint *ep, 4659 const struct sctp_association *asoc, 4660 const sctp_subtype_t type, 4661 void *arg, 4662 sctp_cmd_seq_t *commands) 4663 { 4664 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4665 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4666 4667 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4668 SCTP_STATE(SCTP_STATE_CLOSED)); 4669 4670 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4671 4672 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4673 4674 return SCTP_DISPOSITION_DELETE_TCB; 4675 } 4676 4677 /* 4678 * sctp_cookie_echoed_prm_shutdown 4679 * 4680 * Section: 4 Note: 2 4681 * Verification Tag: 4682 * Inputs 4683 * (endpoint, asoc) 4684 * 4685 * The RFC does not explcitly address this issue, but is the route through the 4686 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4687 * 4688 * Outputs 4689 * (timers) 4690 */ 4691 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4692 const struct sctp_endpoint *ep, 4693 const struct sctp_association *asoc, 4694 const sctp_subtype_t type, 4695 void *arg, sctp_cmd_seq_t *commands) 4696 { 4697 /* There is a single T1 timer, so we should be able to use 4698 * common function with the COOKIE-WAIT state. 4699 */ 4700 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4701 } 4702 4703 /* 4704 * sctp_sf_cookie_wait_prm_abort 4705 * 4706 * Section: 4 Note: 2 4707 * Verification Tag: 4708 * Inputs 4709 * (endpoint, asoc) 4710 * 4711 * The RFC does not explicitly address this issue, but is the route through the 4712 * state table when someone issues an abort while in COOKIE_WAIT state. 4713 * 4714 * Outputs 4715 * (timers) 4716 */ 4717 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4718 const struct sctp_endpoint *ep, 4719 const struct sctp_association *asoc, 4720 const sctp_subtype_t type, 4721 void *arg, 4722 sctp_cmd_seq_t *commands) 4723 { 4724 struct sctp_chunk *abort = arg; 4725 sctp_disposition_t retval; 4726 4727 /* Stop T1-init timer */ 4728 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4729 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4730 retval = SCTP_DISPOSITION_CONSUME; 4731 4732 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4733 4734 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4735 SCTP_STATE(SCTP_STATE_CLOSED)); 4736 4737 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4738 4739 /* Even if we can't send the ABORT due to low memory delete the 4740 * TCB. This is a departure from our typical NOMEM handling. 4741 */ 4742 4743 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4744 SCTP_ERROR(ECONNREFUSED)); 4745 /* Delete the established association. */ 4746 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4747 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4748 4749 return retval; 4750 } 4751 4752 /* 4753 * sctp_sf_cookie_echoed_prm_abort 4754 * 4755 * Section: 4 Note: 3 4756 * Verification Tag: 4757 * Inputs 4758 * (endpoint, asoc) 4759 * 4760 * The RFC does not explcitly address this issue, but is the route through the 4761 * state table when someone issues an abort while in COOKIE_ECHOED state. 4762 * 4763 * Outputs 4764 * (timers) 4765 */ 4766 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4767 const struct sctp_endpoint *ep, 4768 const struct sctp_association *asoc, 4769 const sctp_subtype_t type, 4770 void *arg, 4771 sctp_cmd_seq_t *commands) 4772 { 4773 /* There is a single T1 timer, so we should be able to use 4774 * common function with the COOKIE-WAIT state. 4775 */ 4776 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4777 } 4778 4779 /* 4780 * sctp_sf_shutdown_pending_prm_abort 4781 * 4782 * Inputs 4783 * (endpoint, asoc) 4784 * 4785 * The RFC does not explicitly address this issue, but is the route through the 4786 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4787 * 4788 * Outputs 4789 * (timers) 4790 */ 4791 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4792 const struct sctp_endpoint *ep, 4793 const struct sctp_association *asoc, 4794 const sctp_subtype_t type, 4795 void *arg, 4796 sctp_cmd_seq_t *commands) 4797 { 4798 /* Stop the T5-shutdown guard timer. */ 4799 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4800 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4801 4802 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4803 } 4804 4805 /* 4806 * sctp_sf_shutdown_sent_prm_abort 4807 * 4808 * Inputs 4809 * (endpoint, asoc) 4810 * 4811 * The RFC does not explicitly address this issue, but is the route through the 4812 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4813 * 4814 * Outputs 4815 * (timers) 4816 */ 4817 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4818 const struct sctp_endpoint *ep, 4819 const struct sctp_association *asoc, 4820 const sctp_subtype_t type, 4821 void *arg, 4822 sctp_cmd_seq_t *commands) 4823 { 4824 /* Stop the T2-shutdown timer. */ 4825 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4826 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4827 4828 /* Stop the T5-shutdown guard timer. */ 4829 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4830 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4831 4832 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4833 } 4834 4835 /* 4836 * sctp_sf_cookie_echoed_prm_abort 4837 * 4838 * Inputs 4839 * (endpoint, asoc) 4840 * 4841 * The RFC does not explcitly address this issue, but is the route through the 4842 * state table when someone issues an abort while in COOKIE_ECHOED state. 4843 * 4844 * Outputs 4845 * (timers) 4846 */ 4847 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4848 const struct sctp_endpoint *ep, 4849 const struct sctp_association *asoc, 4850 const sctp_subtype_t type, 4851 void *arg, 4852 sctp_cmd_seq_t *commands) 4853 { 4854 /* The same T2 timer, so we should be able to use 4855 * common function with the SHUTDOWN-SENT state. 4856 */ 4857 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4858 } 4859 4860 /* 4861 * Process the REQUESTHEARTBEAT primitive 4862 * 4863 * 10.1 ULP-to-SCTP 4864 * J) Request Heartbeat 4865 * 4866 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4867 * 4868 * -> result 4869 * 4870 * Instructs the local endpoint to perform a HeartBeat on the specified 4871 * destination transport address of the given association. The returned 4872 * result should indicate whether the transmission of the HEARTBEAT 4873 * chunk to the destination address is successful. 4874 * 4875 * Mandatory attributes: 4876 * 4877 * o association id - local handle to the SCTP association 4878 * 4879 * o destination transport address - the transport address of the 4880 * association on which a heartbeat should be issued. 4881 */ 4882 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4883 const struct sctp_endpoint *ep, 4884 const struct sctp_association *asoc, 4885 const sctp_subtype_t type, 4886 void *arg, 4887 sctp_cmd_seq_t *commands) 4888 { 4889 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 4890 (struct sctp_transport *)arg, commands)) 4891 return SCTP_DISPOSITION_NOMEM; 4892 4893 /* 4894 * RFC 2960 (bis), section 8.3 4895 * 4896 * D) Request an on-demand HEARTBEAT on a specific destination 4897 * transport address of a given association. 4898 * 4899 * The endpoint should increment the respective error counter of 4900 * the destination transport address each time a HEARTBEAT is sent 4901 * to that address and not acknowledged within one RTO. 4902 * 4903 */ 4904 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 4905 SCTP_TRANSPORT(arg)); 4906 return SCTP_DISPOSITION_CONSUME; 4907 } 4908 4909 /* 4910 * ADDIP Section 4.1 ASCONF Chunk Procedures 4911 * When an endpoint has an ASCONF signaled change to be sent to the 4912 * remote endpoint it should do A1 to A9 4913 */ 4914 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 4915 const struct sctp_association *asoc, 4916 const sctp_subtype_t type, 4917 void *arg, 4918 sctp_cmd_seq_t *commands) 4919 { 4920 struct sctp_chunk *chunk = arg; 4921 4922 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4923 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4924 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4925 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4926 return SCTP_DISPOSITION_CONSUME; 4927 } 4928 4929 /* 4930 * Ignore the primitive event 4931 * 4932 * The return value is the disposition of the primitive. 4933 */ 4934 sctp_disposition_t sctp_sf_ignore_primitive( 4935 const struct sctp_endpoint *ep, 4936 const struct sctp_association *asoc, 4937 const sctp_subtype_t type, 4938 void *arg, 4939 sctp_cmd_seq_t *commands) 4940 { 4941 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 4942 return SCTP_DISPOSITION_DISCARD; 4943 } 4944 4945 /*************************************************************************** 4946 * These are the state functions for the OTHER events. 4947 ***************************************************************************/ 4948 4949 /* 4950 * Start the shutdown negotiation. 4951 * 4952 * From Section 9.2: 4953 * Once all its outstanding data has been acknowledged, the endpoint 4954 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 4955 * TSN Ack field the last sequential TSN it has received from the peer. 4956 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 4957 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 4958 * with the updated last sequential TSN received from its peer. 4959 * 4960 * The return value is the disposition. 4961 */ 4962 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 4963 const struct sctp_endpoint *ep, 4964 const struct sctp_association *asoc, 4965 const sctp_subtype_t type, 4966 void *arg, 4967 sctp_cmd_seq_t *commands) 4968 { 4969 struct sctp_chunk *reply; 4970 4971 /* Once all its outstanding data has been acknowledged, the 4972 * endpoint shall send a SHUTDOWN chunk to its peer including 4973 * in the Cumulative TSN Ack field the last sequential TSN it 4974 * has received from the peer. 4975 */ 4976 reply = sctp_make_shutdown(asoc, NULL); 4977 if (!reply) 4978 goto nomem; 4979 4980 /* Set the transport for the SHUTDOWN chunk and the timeout for the 4981 * T2-shutdown timer. 4982 */ 4983 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4984 4985 /* It shall then start the T2-shutdown timer */ 4986 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4987 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4988 4989 /* RFC 4960 Section 9.2 4990 * The sender of the SHUTDOWN MAY also start an overall guard timer 4991 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4992 */ 4993 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4994 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4995 4996 if (asoc->autoclose) 4997 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4998 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4999 5000 /* and enter the SHUTDOWN-SENT state. */ 5001 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5002 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5003 5004 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5005 * 5006 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5007 * or SHUTDOWN-ACK. 5008 */ 5009 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5010 5011 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5012 5013 return SCTP_DISPOSITION_CONSUME; 5014 5015 nomem: 5016 return SCTP_DISPOSITION_NOMEM; 5017 } 5018 5019 /* 5020 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5021 * 5022 * From Section 9.2: 5023 * 5024 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5025 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5026 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5027 * endpoint must re-send the SHUTDOWN ACK. 5028 * 5029 * The return value is the disposition. 5030 */ 5031 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5032 const struct sctp_endpoint *ep, 5033 const struct sctp_association *asoc, 5034 const sctp_subtype_t type, 5035 void *arg, 5036 sctp_cmd_seq_t *commands) 5037 { 5038 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5039 struct sctp_chunk *reply; 5040 5041 /* There are 2 ways of getting here: 5042 * 1) called in response to a SHUTDOWN chunk 5043 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5044 * 5045 * For the case (2), the arg parameter is set to NULL. We need 5046 * to check that we have a chunk before accessing it's fields. 5047 */ 5048 if (chunk) { 5049 if (!sctp_vtag_verify(chunk, asoc)) 5050 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 5051 5052 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5053 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5054 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 5055 commands); 5056 } 5057 5058 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5059 * shall send a SHUTDOWN ACK ... 5060 */ 5061 reply = sctp_make_shutdown_ack(asoc, chunk); 5062 if (!reply) 5063 goto nomem; 5064 5065 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5066 * the T2-shutdown timer. 5067 */ 5068 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5069 5070 /* and start/restart a T2-shutdown timer of its own, */ 5071 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5072 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5073 5074 if (asoc->autoclose) 5075 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5076 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5077 5078 /* Enter the SHUTDOWN-ACK-SENT state. */ 5079 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5080 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5081 5082 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5083 * 5084 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5085 * or SHUTDOWN-ACK. 5086 */ 5087 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5088 5089 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5090 5091 return SCTP_DISPOSITION_CONSUME; 5092 5093 nomem: 5094 return SCTP_DISPOSITION_NOMEM; 5095 } 5096 5097 /* 5098 * Ignore the event defined as other 5099 * 5100 * The return value is the disposition of the event. 5101 */ 5102 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 5103 const struct sctp_association *asoc, 5104 const sctp_subtype_t type, 5105 void *arg, 5106 sctp_cmd_seq_t *commands) 5107 { 5108 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5109 return SCTP_DISPOSITION_DISCARD; 5110 } 5111 5112 /************************************************************ 5113 * These are the state functions for handling timeout events. 5114 ************************************************************/ 5115 5116 /* 5117 * RTX Timeout 5118 * 5119 * Section: 6.3.3 Handle T3-rtx Expiration 5120 * 5121 * Whenever the retransmission timer T3-rtx expires for a destination 5122 * address, do the following: 5123 * [See below] 5124 * 5125 * The return value is the disposition of the chunk. 5126 */ 5127 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 5128 const struct sctp_association *asoc, 5129 const sctp_subtype_t type, 5130 void *arg, 5131 sctp_cmd_seq_t *commands) 5132 { 5133 struct sctp_transport *transport = arg; 5134 5135 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS); 5136 5137 if (asoc->overall_error_count >= asoc->max_retrans) { 5138 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5139 SCTP_ERROR(ETIMEDOUT)); 5140 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5141 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5142 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5143 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5144 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5145 return SCTP_DISPOSITION_DELETE_TCB; 5146 } 5147 5148 /* E1) For the destination address for which the timer 5149 * expires, adjust its ssthresh with rules defined in Section 5150 * 7.2.3 and set the cwnd <- MTU. 5151 */ 5152 5153 /* E2) For the destination address for which the timer 5154 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5155 * maximum value discussed in rule C7 above (RTO.max) may be 5156 * used to provide an upper bound to this doubling operation. 5157 */ 5158 5159 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5160 * outstanding DATA chunks for the address for which the 5161 * T3-rtx has expired will fit into a single packet, subject 5162 * to the MTU constraint for the path corresponding to the 5163 * destination transport address to which the retransmission 5164 * is being sent (this may be different from the address for 5165 * which the timer expires [see Section 6.4]). Call this 5166 * value K. Bundle and retransmit those K DATA chunks in a 5167 * single packet to the destination endpoint. 5168 * 5169 * Note: Any DATA chunks that were sent to the address for 5170 * which the T3-rtx timer expired but did not fit in one MTU 5171 * (rule E3 above), should be marked for retransmission and 5172 * sent as soon as cwnd allows (normally when a SACK arrives). 5173 */ 5174 5175 /* Do some failure management (Section 8.2). */ 5176 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5177 5178 /* NB: Rules E4 and F1 are implicit in R1. */ 5179 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5180 5181 return SCTP_DISPOSITION_CONSUME; 5182 } 5183 5184 /* 5185 * Generate delayed SACK on timeout 5186 * 5187 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5188 * 5189 * The guidelines on delayed acknowledgement algorithm specified in 5190 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5191 * acknowledgement SHOULD be generated for at least every second packet 5192 * (not every second DATA chunk) received, and SHOULD be generated 5193 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5194 * some situations it may be beneficial for an SCTP transmitter to be 5195 * more conservative than the algorithms detailed in this document 5196 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5197 * the following algorithms allow. 5198 */ 5199 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 5200 const struct sctp_association *asoc, 5201 const sctp_subtype_t type, 5202 void *arg, 5203 sctp_cmd_seq_t *commands) 5204 { 5205 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS); 5206 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5207 return SCTP_DISPOSITION_CONSUME; 5208 } 5209 5210 /* 5211 * sctp_sf_t1_init_timer_expire 5212 * 5213 * Section: 4 Note: 2 5214 * Verification Tag: 5215 * Inputs 5216 * (endpoint, asoc) 5217 * 5218 * RFC 2960 Section 4 Notes 5219 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5220 * and re-start the T1-init timer without changing state. This MUST 5221 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5222 * endpoint MUST abort the initialization process and report the 5223 * error to SCTP user. 5224 * 5225 * Outputs 5226 * (timers, events) 5227 * 5228 */ 5229 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 5230 const struct sctp_association *asoc, 5231 const sctp_subtype_t type, 5232 void *arg, 5233 sctp_cmd_seq_t *commands) 5234 { 5235 struct sctp_chunk *repl = NULL; 5236 struct sctp_bind_addr *bp; 5237 int attempts = asoc->init_err_counter + 1; 5238 5239 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5240 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS); 5241 5242 if (attempts <= asoc->max_init_attempts) { 5243 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5244 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5245 if (!repl) 5246 return SCTP_DISPOSITION_NOMEM; 5247 5248 /* Choose transport for INIT. */ 5249 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5250 SCTP_CHUNK(repl)); 5251 5252 /* Issue a sideeffect to do the needed accounting. */ 5253 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5254 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5255 5256 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5257 } else { 5258 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5259 " max_init_attempts: %d\n", 5260 attempts, asoc->max_init_attempts); 5261 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5262 SCTP_ERROR(ETIMEDOUT)); 5263 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5264 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5265 return SCTP_DISPOSITION_DELETE_TCB; 5266 } 5267 5268 return SCTP_DISPOSITION_CONSUME; 5269 } 5270 5271 /* 5272 * sctp_sf_t1_cookie_timer_expire 5273 * 5274 * Section: 4 Note: 2 5275 * Verification Tag: 5276 * Inputs 5277 * (endpoint, asoc) 5278 * 5279 * RFC 2960 Section 4 Notes 5280 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5281 * COOKIE ECHO and re-start the T1-cookie timer without changing 5282 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5283 * After that, the endpoint MUST abort the initialization process and 5284 * report the error to SCTP user. 5285 * 5286 * Outputs 5287 * (timers, events) 5288 * 5289 */ 5290 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 5291 const struct sctp_association *asoc, 5292 const sctp_subtype_t type, 5293 void *arg, 5294 sctp_cmd_seq_t *commands) 5295 { 5296 struct sctp_chunk *repl = NULL; 5297 int attempts = asoc->init_err_counter + 1; 5298 5299 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5300 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS); 5301 5302 if (attempts <= asoc->max_init_attempts) { 5303 repl = sctp_make_cookie_echo(asoc, NULL); 5304 if (!repl) 5305 return SCTP_DISPOSITION_NOMEM; 5306 5307 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5308 SCTP_CHUNK(repl)); 5309 /* Issue a sideeffect to do the needed accounting. */ 5310 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5311 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5312 5313 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5314 } else { 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 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5326 * with the updated last sequential TSN received from its peer. 5327 * 5328 * An endpoint should limit the number of retransmissions of the 5329 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5330 * If this threshold is exceeded the endpoint should destroy the TCB and 5331 * MUST report the peer endpoint unreachable to the upper layer (and 5332 * thus the association enters the CLOSED state). The reception of any 5333 * packet from its peer (i.e. as the peer sends all of its queued DATA 5334 * chunks) should clear the endpoint's retransmission count and restart 5335 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5336 * all of its queued DATA chunks that have not yet been sent. 5337 */ 5338 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 5339 const struct sctp_association *asoc, 5340 const sctp_subtype_t type, 5341 void *arg, 5342 sctp_cmd_seq_t *commands) 5343 { 5344 struct sctp_chunk *reply = NULL; 5345 5346 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 5347 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5348 5349 ((struct sctp_association *)asoc)->shutdown_retries++; 5350 5351 if (asoc->overall_error_count >= asoc->max_retrans) { 5352 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5353 SCTP_ERROR(ETIMEDOUT)); 5354 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5355 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5356 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5357 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5358 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5359 return SCTP_DISPOSITION_DELETE_TCB; 5360 } 5361 5362 switch (asoc->state) { 5363 case SCTP_STATE_SHUTDOWN_SENT: 5364 reply = sctp_make_shutdown(asoc, NULL); 5365 break; 5366 5367 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5368 reply = sctp_make_shutdown_ack(asoc, NULL); 5369 break; 5370 5371 default: 5372 BUG(); 5373 break; 5374 } 5375 5376 if (!reply) 5377 goto nomem; 5378 5379 /* Do some failure management (Section 8.2). */ 5380 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5381 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5382 5383 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5384 * the T2-shutdown timer. 5385 */ 5386 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5387 5388 /* Restart the T2-shutdown timer. */ 5389 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5390 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5391 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5392 return SCTP_DISPOSITION_CONSUME; 5393 5394 nomem: 5395 return SCTP_DISPOSITION_NOMEM; 5396 } 5397 5398 /* 5399 * ADDIP Section 4.1 ASCONF CHunk Procedures 5400 * If the T4 RTO timer expires the endpoint should do B1 to B5 5401 */ 5402 sctp_disposition_t sctp_sf_t4_timer_expire( 5403 const struct sctp_endpoint *ep, 5404 const struct sctp_association *asoc, 5405 const sctp_subtype_t type, 5406 void *arg, 5407 sctp_cmd_seq_t *commands) 5408 { 5409 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5410 struct sctp_transport *transport = chunk->transport; 5411 5412 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS); 5413 5414 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5415 * detection on the appropriate destination address as defined in 5416 * RFC2960 [5] section 8.1 and 8.2. 5417 */ 5418 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5419 5420 /* Reconfig T4 timer and transport. */ 5421 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5422 5423 /* ADDIP 4.1 B2) Increment the association error counters and perform 5424 * endpoint failure detection on the association as defined in 5425 * RFC2960 [5] section 8.1 and 8.2. 5426 * association error counter is incremented in SCTP_CMD_STRIKE. 5427 */ 5428 if (asoc->overall_error_count >= asoc->max_retrans) { 5429 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5430 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5431 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5432 SCTP_ERROR(ETIMEDOUT)); 5433 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5434 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5435 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5436 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5437 return SCTP_DISPOSITION_ABORT; 5438 } 5439 5440 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5441 * the ASCONF chunk was sent by doubling the RTO timer value. 5442 * This is done in SCTP_CMD_STRIKE. 5443 */ 5444 5445 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5446 * choose an alternate destination address (please refer to RFC2960 5447 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5448 * chunk, it MUST be the same (including its serial number) as the last 5449 * ASCONF sent. 5450 */ 5451 sctp_chunk_hold(asoc->addip_last_asconf); 5452 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5453 SCTP_CHUNK(asoc->addip_last_asconf)); 5454 5455 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5456 * destination is selected, then the RTO used will be that of the new 5457 * destination address. 5458 */ 5459 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5460 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5461 5462 return SCTP_DISPOSITION_CONSUME; 5463 } 5464 5465 /* sctpimpguide-05 Section 2.12.2 5466 * The sender of the SHUTDOWN MAY also start an overall guard timer 5467 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5468 * At the expiration of this timer the sender SHOULD abort the association 5469 * by sending an ABORT chunk. 5470 */ 5471 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 5472 const struct sctp_association *asoc, 5473 const sctp_subtype_t type, 5474 void *arg, 5475 sctp_cmd_seq_t *commands) 5476 { 5477 struct sctp_chunk *reply = NULL; 5478 5479 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5480 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5481 5482 reply = sctp_make_abort(asoc, NULL, 0); 5483 if (!reply) 5484 goto nomem; 5485 5486 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5487 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5488 SCTP_ERROR(ETIMEDOUT)); 5489 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5490 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5491 5492 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5493 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5494 5495 return SCTP_DISPOSITION_DELETE_TCB; 5496 nomem: 5497 return SCTP_DISPOSITION_NOMEM; 5498 } 5499 5500 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5501 * the association is automatically closed by starting the shutdown process. 5502 * The work that needs to be done is same as when SHUTDOWN is initiated by 5503 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5504 */ 5505 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5506 const struct sctp_endpoint *ep, 5507 const struct sctp_association *asoc, 5508 const sctp_subtype_t type, 5509 void *arg, 5510 sctp_cmd_seq_t *commands) 5511 { 5512 int disposition; 5513 5514 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS); 5515 5516 /* From 9.2 Shutdown of an Association 5517 * Upon receipt of the SHUTDOWN primitive from its upper 5518 * layer, the endpoint enters SHUTDOWN-PENDING state and 5519 * remains there until all outstanding data has been 5520 * acknowledged by its peer. The endpoint accepts no new data 5521 * from its upper layer, but retransmits data to the far end 5522 * if necessary to fill gaps. 5523 */ 5524 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5525 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5526 5527 disposition = SCTP_DISPOSITION_CONSUME; 5528 if (sctp_outq_is_empty(&asoc->outqueue)) { 5529 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 5530 arg, commands); 5531 } 5532 return disposition; 5533 } 5534 5535 /***************************************************************************** 5536 * These are sa state functions which could apply to all types of events. 5537 ****************************************************************************/ 5538 5539 /* 5540 * This table entry is not implemented. 5541 * 5542 * Inputs 5543 * (endpoint, asoc, chunk) 5544 * 5545 * The return value is the disposition of the chunk. 5546 */ 5547 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 5548 const struct sctp_association *asoc, 5549 const sctp_subtype_t type, 5550 void *arg, 5551 sctp_cmd_seq_t *commands) 5552 { 5553 return SCTP_DISPOSITION_NOT_IMPL; 5554 } 5555 5556 /* 5557 * This table entry represents a bug. 5558 * 5559 * Inputs 5560 * (endpoint, asoc, chunk) 5561 * 5562 * The return value is the disposition of the chunk. 5563 */ 5564 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 5565 const struct sctp_association *asoc, 5566 const sctp_subtype_t type, 5567 void *arg, 5568 sctp_cmd_seq_t *commands) 5569 { 5570 return SCTP_DISPOSITION_BUG; 5571 } 5572 5573 /* 5574 * This table entry represents the firing of a timer in the wrong state. 5575 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5576 * when the association is in the wrong state. This event should 5577 * be ignored, so as to prevent any rearming of the timer. 5578 * 5579 * Inputs 5580 * (endpoint, asoc, chunk) 5581 * 5582 * The return value is the disposition of the chunk. 5583 */ 5584 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 5585 const struct sctp_association *asoc, 5586 const sctp_subtype_t type, 5587 void *arg, 5588 sctp_cmd_seq_t *commands) 5589 { 5590 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5591 return SCTP_DISPOSITION_CONSUME; 5592 } 5593 5594 /******************************************************************** 5595 * 2nd Level Abstractions 5596 ********************************************************************/ 5597 5598 /* Pull the SACK chunk based on the SACK header. */ 5599 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5600 { 5601 struct sctp_sackhdr *sack; 5602 unsigned int len; 5603 __u16 num_blocks; 5604 __u16 num_dup_tsns; 5605 5606 /* Protect ourselves from reading too far into 5607 * the skb from a bogus sender. 5608 */ 5609 sack = (struct sctp_sackhdr *) chunk->skb->data; 5610 5611 num_blocks = ntohs(sack->num_gap_ack_blocks); 5612 num_dup_tsns = ntohs(sack->num_dup_tsns); 5613 len = sizeof(struct sctp_sackhdr); 5614 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5615 if (len > chunk->skb->len) 5616 return NULL; 5617 5618 skb_pull(chunk->skb, len); 5619 5620 return sack; 5621 } 5622 5623 /* Create an ABORT packet to be sent as a response, with the specified 5624 * error causes. 5625 */ 5626 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5627 const struct sctp_association *asoc, 5628 struct sctp_chunk *chunk, 5629 const void *payload, 5630 size_t paylen) 5631 { 5632 struct sctp_packet *packet; 5633 struct sctp_chunk *abort; 5634 5635 packet = sctp_ootb_pkt_new(asoc, chunk); 5636 5637 if (packet) { 5638 /* Make an ABORT. 5639 * The T bit will be set if the asoc is NULL. 5640 */ 5641 abort = sctp_make_abort(asoc, chunk, paylen); 5642 if (!abort) { 5643 sctp_ootb_pkt_free(packet); 5644 return NULL; 5645 } 5646 5647 /* Reflect vtag if T-Bit is set */ 5648 if (sctp_test_T_bit(abort)) 5649 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5650 5651 /* Add specified error causes, i.e., payload, to the 5652 * end of the chunk. 5653 */ 5654 sctp_addto_chunk(abort, paylen, payload); 5655 5656 /* Set the skb to the belonging sock for accounting. */ 5657 abort->skb->sk = ep->base.sk; 5658 5659 sctp_packet_append_chunk(packet, abort); 5660 5661 } 5662 5663 return packet; 5664 } 5665 5666 /* Allocate a packet for responding in the OOTB conditions. */ 5667 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5668 const struct sctp_chunk *chunk) 5669 { 5670 struct sctp_packet *packet; 5671 struct sctp_transport *transport; 5672 __u16 sport; 5673 __u16 dport; 5674 __u32 vtag; 5675 5676 /* Get the source and destination port from the inbound packet. */ 5677 sport = ntohs(chunk->sctp_hdr->dest); 5678 dport = ntohs(chunk->sctp_hdr->source); 5679 5680 /* The V-tag is going to be the same as the inbound packet if no 5681 * association exists, otherwise, use the peer's vtag. 5682 */ 5683 if (asoc) { 5684 /* Special case the INIT-ACK as there is no peer's vtag 5685 * yet. 5686 */ 5687 switch(chunk->chunk_hdr->type) { 5688 case SCTP_CID_INIT_ACK: 5689 { 5690 sctp_initack_chunk_t *initack; 5691 5692 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5693 vtag = ntohl(initack->init_hdr.init_tag); 5694 break; 5695 } 5696 default: 5697 vtag = asoc->peer.i.init_tag; 5698 break; 5699 } 5700 } else { 5701 /* Special case the INIT and stale COOKIE_ECHO as there is no 5702 * vtag yet. 5703 */ 5704 switch(chunk->chunk_hdr->type) { 5705 case SCTP_CID_INIT: 5706 { 5707 sctp_init_chunk_t *init; 5708 5709 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5710 vtag = ntohl(init->init_hdr.init_tag); 5711 break; 5712 } 5713 default: 5714 vtag = ntohl(chunk->sctp_hdr->vtag); 5715 break; 5716 } 5717 } 5718 5719 /* Make a transport for the bucket, Eliza... */ 5720 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5721 if (!transport) 5722 goto nomem; 5723 5724 /* Cache a route for the transport with the chunk's destination as 5725 * the source address. 5726 */ 5727 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5728 sctp_sk(sctp_get_ctl_sock())); 5729 5730 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5731 packet = sctp_packet_config(packet, vtag, 0); 5732 5733 return packet; 5734 5735 nomem: 5736 return NULL; 5737 } 5738 5739 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5740 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5741 { 5742 sctp_transport_free(packet->transport); 5743 } 5744 5745 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5746 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5747 const struct sctp_association *asoc, 5748 const struct sctp_chunk *chunk, 5749 sctp_cmd_seq_t *commands, 5750 struct sctp_chunk *err_chunk) 5751 { 5752 struct sctp_packet *packet; 5753 5754 if (err_chunk) { 5755 packet = sctp_ootb_pkt_new(asoc, chunk); 5756 if (packet) { 5757 struct sctp_signed_cookie *cookie; 5758 5759 /* Override the OOTB vtag from the cookie. */ 5760 cookie = chunk->subh.cookie_hdr; 5761 packet->vtag = cookie->c.peer_vtag; 5762 5763 /* Set the skb to the belonging sock for accounting. */ 5764 err_chunk->skb->sk = ep->base.sk; 5765 sctp_packet_append_chunk(packet, err_chunk); 5766 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5767 SCTP_PACKET(packet)); 5768 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5769 } else 5770 sctp_chunk_free (err_chunk); 5771 } 5772 } 5773 5774 5775 /* Process a data chunk */ 5776 static int sctp_eat_data(const struct sctp_association *asoc, 5777 struct sctp_chunk *chunk, 5778 sctp_cmd_seq_t *commands) 5779 { 5780 sctp_datahdr_t *data_hdr; 5781 struct sctp_chunk *err; 5782 size_t datalen; 5783 sctp_verb_t deliver; 5784 int tmp; 5785 __u32 tsn; 5786 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 5787 struct sock *sk = asoc->base.sk; 5788 5789 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5790 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5791 5792 tsn = ntohl(data_hdr->tsn); 5793 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5794 5795 /* ASSERT: Now skb->data is really the user data. */ 5796 5797 /* Process ECN based congestion. 5798 * 5799 * Since the chunk structure is reused for all chunks within 5800 * a packet, we use ecn_ce_done to track if we've already 5801 * done CE processing for this packet. 5802 * 5803 * We need to do ECN processing even if we plan to discard the 5804 * chunk later. 5805 */ 5806 5807 if (!chunk->ecn_ce_done) { 5808 struct sctp_af *af; 5809 chunk->ecn_ce_done = 1; 5810 5811 af = sctp_get_af_specific( 5812 ipver2af(ip_hdr(chunk->skb)->version)); 5813 5814 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5815 /* Do real work as sideffect. */ 5816 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5817 SCTP_U32(tsn)); 5818 } 5819 } 5820 5821 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5822 if (tmp < 0) { 5823 /* The TSN is too high--silently discard the chunk and 5824 * count on it getting retransmitted later. 5825 */ 5826 return SCTP_IERROR_HIGH_TSN; 5827 } else if (tmp > 0) { 5828 /* This is a duplicate. Record it. */ 5829 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5830 return SCTP_IERROR_DUP_TSN; 5831 } 5832 5833 /* This is a new TSN. */ 5834 5835 /* Discard if there is no room in the receive window. 5836 * Actually, allow a little bit of overflow (up to a MTU). 5837 */ 5838 datalen = ntohs(chunk->chunk_hdr->length); 5839 datalen -= sizeof(sctp_data_chunk_t); 5840 5841 deliver = SCTP_CMD_CHUNK_ULP; 5842 5843 /* Think about partial delivery. */ 5844 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5845 5846 /* Even if we don't accept this chunk there is 5847 * memory pressure. 5848 */ 5849 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5850 } 5851 5852 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5853 * seems a bit troublesome in that frag_point varies based on 5854 * PMTU. In cases, such as loopback, this might be a rather 5855 * large spill over. 5856 */ 5857 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 5858 (datalen > asoc->rwnd + asoc->frag_point))) { 5859 5860 /* If this is the next TSN, consider reneging to make 5861 * room. Note: Playing nice with a confused sender. A 5862 * malicious sender can still eat up all our buffer 5863 * space and in the future we may want to detect and 5864 * do more drastic reneging. 5865 */ 5866 if (sctp_tsnmap_has_gap(map) && 5867 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5868 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5869 deliver = SCTP_CMD_RENEGE; 5870 } else { 5871 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5872 "rwnd: %d\n", tsn, datalen, 5873 asoc->rwnd); 5874 return SCTP_IERROR_IGNORE_TSN; 5875 } 5876 } 5877 5878 /* 5879 * Also try to renege to limit our memory usage in the event that 5880 * we are under memory pressure 5881 * If we can't renege, don't worry about it, the sk_rmem_schedule 5882 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 5883 * memory usage too much 5884 */ 5885 if (*sk->sk_prot_creator->memory_pressure) { 5886 if (sctp_tsnmap_has_gap(map) && 5887 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5888 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 5889 deliver = SCTP_CMD_RENEGE; 5890 } 5891 } 5892 5893 /* 5894 * Section 3.3.10.9 No User Data (9) 5895 * 5896 * Cause of error 5897 * --------------- 5898 * No User Data: This error cause is returned to the originator of a 5899 * DATA chunk if a received DATA chunk has no user data. 5900 */ 5901 if (unlikely(0 == datalen)) { 5902 err = sctp_make_abort_no_data(asoc, chunk, tsn); 5903 if (err) { 5904 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5905 SCTP_CHUNK(err)); 5906 } 5907 /* We are going to ABORT, so we might as well stop 5908 * processing the rest of the chunks in the packet. 5909 */ 5910 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 5911 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5912 SCTP_ERROR(ECONNABORTED)); 5913 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5914 SCTP_PERR(SCTP_ERROR_NO_DATA)); 5915 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5916 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5917 return SCTP_IERROR_NO_DATA; 5918 } 5919 5920 chunk->data_accepted = 1; 5921 5922 /* Note: Some chunks may get overcounted (if we drop) or overcounted 5923 * if we renege and the chunk arrives again. 5924 */ 5925 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 5926 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 5927 else 5928 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 5929 5930 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 5931 * 5932 * If an endpoint receive a DATA chunk with an invalid stream 5933 * identifier, it shall acknowledge the reception of the DATA chunk 5934 * following the normal procedure, immediately send an ERROR chunk 5935 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 5936 * and discard the DATA chunk. 5937 */ 5938 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { 5939 /* Mark tsn as received even though we drop it */ 5940 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 5941 5942 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 5943 &data_hdr->stream, 5944 sizeof(data_hdr->stream)); 5945 if (err) 5946 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5947 SCTP_CHUNK(err)); 5948 return SCTP_IERROR_BAD_STREAM; 5949 } 5950 5951 /* Send the data up to the user. Note: Schedule the 5952 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 5953 * chunk needs the updated rwnd. 5954 */ 5955 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 5956 5957 return SCTP_IERROR_NO_ERROR; 5958 } 5959