1 /* SCTP kernel reference 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 file is part of the SCTP kernel reference Implementation 9 * 10 * This is part of the SCTP Linux Kernel Reference Implementation. 11 * 12 * These are the state functions for the state machine. 13 * 14 * The SCTP reference implementation is free software; 15 * you can redistribute it and/or modify it under the terms of 16 * the GNU General Public License as published by 17 * the Free Software Foundation; either version 2, or (at your option) 18 * any later version. 19 * 20 * The SCTP reference implementation is distributed in the hope that it 21 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 22 * ************************ 23 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 24 * See the GNU General Public License for more details. 25 * 26 * You should have received a copy of the GNU General Public License 27 * along with GNU CC; see the file COPYING. If not, write to 28 * the Free Software Foundation, 59 Temple Place - Suite 330, 29 * Boston, MA 02111-1307, USA. 30 * 31 * Please send any bug reports or fixes you make to the 32 * email address(es): 33 * lksctp developers <lksctp-developers@lists.sourceforge.net> 34 * 35 * Or submit a bug report through the following website: 36 * http://www.sf.net/projects/lksctp 37 * 38 * Written or modified by: 39 * La Monte H.P. Yarroll <piggy@acm.org> 40 * Karl Knutson <karl@athena.chicago.il.us> 41 * Mathew Kotowsky <kotowsky@sctp.org> 42 * Sridhar Samudrala <samudrala@us.ibm.com> 43 * Jon Grimm <jgrimm@us.ibm.com> 44 * Hui Huang <hui.huang@nokia.com> 45 * Dajiang Zhang <dajiang.zhang@nokia.com> 46 * Daisy Chang <daisyc@us.ibm.com> 47 * Ardelle Fan <ardelle.fan@intel.com> 48 * Ryan Layer <rmlayer@us.ibm.com> 49 * Kevin Gao <kevin.gao@intel.com> 50 * 51 * Any bugs reported given to us we will try to fix... any fixes shared will 52 * be incorporated into the next SCTP release. 53 */ 54 55 #include <linux/types.h> 56 #include <linux/kernel.h> 57 #include <linux/ip.h> 58 #include <linux/ipv6.h> 59 #include <linux/net.h> 60 #include <linux/inet.h> 61 #include <net/sock.h> 62 #include <net/inet_ecn.h> 63 #include <linux/skbuff.h> 64 #include <net/sctp/sctp.h> 65 #include <net/sctp/sm.h> 66 #include <net/sctp/structs.h> 67 68 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 69 const struct sctp_association *asoc, 70 struct sctp_chunk *chunk, 71 const void *payload, 72 size_t paylen); 73 static int sctp_eat_data(const struct sctp_association *asoc, 74 struct sctp_chunk *chunk, 75 sctp_cmd_seq_t *commands); 76 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 77 const struct sctp_chunk *chunk); 78 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 79 const struct sctp_association *asoc, 80 const struct sctp_chunk *chunk, 81 sctp_cmd_seq_t *commands, 82 struct sctp_chunk *err_chunk); 83 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 84 const struct sctp_association *asoc, 85 const sctp_subtype_t type, 86 void *arg, 87 sctp_cmd_seq_t *commands); 88 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 89 const struct sctp_association *asoc, 90 const sctp_subtype_t type, 91 void *arg, 92 sctp_cmd_seq_t *commands); 93 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 94 const struct sctp_association *asoc, 95 const sctp_subtype_t type, 96 void *arg, 97 sctp_cmd_seq_t *commands); 98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 99 100 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 101 __be16 error, int sk_err, 102 const struct sctp_association *asoc, 103 struct sctp_transport *transport); 104 105 static sctp_disposition_t sctp_sf_abort_violation( 106 const struct sctp_endpoint *ep, 107 const struct sctp_association *asoc, 108 void *arg, 109 sctp_cmd_seq_t *commands, 110 const __u8 *payload, 111 const size_t paylen); 112 113 static sctp_disposition_t sctp_sf_violation_chunklen( 114 const struct sctp_endpoint *ep, 115 const struct sctp_association *asoc, 116 const sctp_subtype_t type, 117 void *arg, 118 sctp_cmd_seq_t *commands); 119 120 static sctp_disposition_t sctp_sf_violation_paramlen( 121 const struct sctp_endpoint *ep, 122 const struct sctp_association *asoc, 123 const sctp_subtype_t type, 124 void *arg, 125 sctp_cmd_seq_t *commands); 126 127 static sctp_disposition_t sctp_sf_violation_ctsn( 128 const struct sctp_endpoint *ep, 129 const struct sctp_association *asoc, 130 const sctp_subtype_t type, 131 void *arg, 132 sctp_cmd_seq_t *commands); 133 134 static sctp_disposition_t sctp_sf_violation_chunk( 135 const struct sctp_endpoint *ep, 136 const struct sctp_association *asoc, 137 const sctp_subtype_t type, 138 void *arg, 139 sctp_cmd_seq_t *commands); 140 141 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const sctp_subtype_t type, 144 struct sctp_chunk *chunk); 145 146 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 147 const struct sctp_association *asoc, 148 const sctp_subtype_t type, 149 void *arg, 150 sctp_cmd_seq_t *commands); 151 152 /* Small helper function that checks if the chunk length 153 * is of the appropriate length. The 'required_length' argument 154 * is set to be the size of a specific chunk we are testing. 155 * Return Values: 1 = Valid length 156 * 0 = Invalid length 157 * 158 */ 159 static inline int 160 sctp_chunk_length_valid(struct sctp_chunk *chunk, 161 __u16 required_length) 162 { 163 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 164 165 if (unlikely(chunk_length < required_length)) 166 return 0; 167 168 return 1; 169 } 170 171 /********************************************************** 172 * These are the state functions for handling chunk events. 173 **********************************************************/ 174 175 /* 176 * Process the final SHUTDOWN COMPLETE. 177 * 178 * Section: 4 (C) (diagram), 9.2 179 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 180 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 181 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 182 * should stop the T2-shutdown timer and remove all knowledge of the 183 * association (and thus the association enters the CLOSED state). 184 * 185 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 186 * C) Rules for packet carrying SHUTDOWN COMPLETE: 187 * ... 188 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 189 * if the Verification Tag field of the packet matches its own tag and 190 * the T bit is not set 191 * OR 192 * it is set to its peer's tag and the T bit is set in the Chunk 193 * Flags. 194 * Otherwise, the receiver MUST silently discard the packet 195 * and take no further action. An endpoint MUST ignore the 196 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 197 * 198 * Inputs 199 * (endpoint, asoc, chunk) 200 * 201 * Outputs 202 * (asoc, reply_msg, msg_up, timers, counters) 203 * 204 * The return value is the disposition of the chunk. 205 */ 206 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, 207 const struct sctp_association *asoc, 208 const sctp_subtype_t type, 209 void *arg, 210 sctp_cmd_seq_t *commands) 211 { 212 struct sctp_chunk *chunk = arg; 213 struct sctp_ulpevent *ev; 214 215 if (!sctp_vtag_verify_either(chunk, asoc)) 216 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 217 218 /* RFC 2960 6.10 Bundling 219 * 220 * An endpoint MUST NOT bundle INIT, INIT ACK or 221 * SHUTDOWN COMPLETE with any other chunks. 222 */ 223 if (!chunk->singleton) 224 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 225 226 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 227 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 228 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 229 commands); 230 231 /* RFC 2960 10.2 SCTP-to-ULP 232 * 233 * H) SHUTDOWN COMPLETE notification 234 * 235 * When SCTP completes the shutdown procedures (section 9.2) this 236 * notification is passed to the upper layer. 237 */ 238 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 239 0, 0, 0, NULL, GFP_ATOMIC); 240 if (ev) 241 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 242 SCTP_ULPEVENT(ev)); 243 244 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 245 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 246 * not the chunk should be discarded. If the endpoint is in 247 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 248 * T2-shutdown timer and remove all knowledge of the 249 * association (and thus the association enters the CLOSED 250 * state). 251 */ 252 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 253 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 254 255 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 256 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 257 258 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 259 SCTP_STATE(SCTP_STATE_CLOSED)); 260 261 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 262 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 263 264 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 265 266 return SCTP_DISPOSITION_DELETE_TCB; 267 } 268 269 /* 270 * Respond to a normal INIT chunk. 271 * We are the side that is being asked for an association. 272 * 273 * Section: 5.1 Normal Establishment of an Association, B 274 * B) "Z" shall respond immediately with an INIT ACK chunk. The 275 * destination IP address of the INIT ACK MUST be set to the source 276 * IP address of the INIT to which this INIT ACK is responding. In 277 * the response, besides filling in other parameters, "Z" must set the 278 * Verification Tag field to Tag_A, and also provide its own 279 * Verification Tag (Tag_Z) in the Initiate Tag field. 280 * 281 * Verification Tag: Must be 0. 282 * 283 * Inputs 284 * (endpoint, asoc, chunk) 285 * 286 * Outputs 287 * (asoc, reply_msg, msg_up, timers, counters) 288 * 289 * The return value is the disposition of the chunk. 290 */ 291 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 292 const struct sctp_association *asoc, 293 const sctp_subtype_t type, 294 void *arg, 295 sctp_cmd_seq_t *commands) 296 { 297 struct sctp_chunk *chunk = arg; 298 struct sctp_chunk *repl; 299 struct sctp_association *new_asoc; 300 struct sctp_chunk *err_chunk; 301 struct sctp_packet *packet; 302 sctp_unrecognized_param_t *unk_param; 303 int len; 304 305 /* 6.10 Bundling 306 * An endpoint MUST NOT bundle INIT, INIT ACK or 307 * SHUTDOWN COMPLETE with any other chunks. 308 * 309 * IG Section 2.11.2 310 * Furthermore, we require that the receiver of an INIT chunk MUST 311 * enforce these rules by silently discarding an arriving packet 312 * with an INIT chunk that is bundled with other chunks. 313 */ 314 if (!chunk->singleton) 315 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 316 317 /* If the packet is an OOTB packet which is temporarily on the 318 * control endpoint, respond with an ABORT. 319 */ 320 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 321 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 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 destory 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 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 642 643 /* Make sure that the COOKIE_ECHO chunk has a valid length. 644 * In this case, we check that we have enough for at least a 645 * chunk header. More detailed verification is done 646 * in sctp_unpack_cookie(). 647 */ 648 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 649 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 650 651 /* If the endpoint is not listening or if the number of associations 652 * on the TCP-style socket exceed the max backlog, respond with an 653 * ABORT. 654 */ 655 sk = ep->base.sk; 656 if (!sctp_sstate(sk, LISTENING) || 657 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 658 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 659 660 /* "Decode" the chunk. We have no optional parameters so we 661 * are in good shape. 662 */ 663 chunk->subh.cookie_hdr = 664 (struct sctp_signed_cookie *)chunk->skb->data; 665 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 666 sizeof(sctp_chunkhdr_t))) 667 goto nomem; 668 669 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 670 * "Z" will reply with a COOKIE ACK chunk after building a TCB 671 * and moving to the ESTABLISHED state. 672 */ 673 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 674 &err_chk_p); 675 676 /* FIXME: 677 * If the re-build failed, what is the proper error path 678 * from here? 679 * 680 * [We should abort the association. --piggy] 681 */ 682 if (!new_asoc) { 683 /* FIXME: Several errors are possible. A bad cookie should 684 * be silently discarded, but think about logging it too. 685 */ 686 switch (error) { 687 case -SCTP_IERROR_NOMEM: 688 goto nomem; 689 690 case -SCTP_IERROR_STALE_COOKIE: 691 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 692 err_chk_p); 693 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 694 695 case -SCTP_IERROR_BAD_SIG: 696 default: 697 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 698 } 699 } 700 701 702 /* Delay state machine commands until later. 703 * 704 * Re-build the bind address for the association is done in 705 * the sctp_unpack_cookie() already. 706 */ 707 /* This is a brand-new association, so these are not yet side 708 * effects--it is safe to run them here. 709 */ 710 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 711 712 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 713 &chunk->subh.cookie_hdr->c.peer_addr, 714 peer_init, GFP_ATOMIC)) 715 goto nomem_init; 716 717 /* SCTP-AUTH: Now that we've populate required fields in 718 * sctp_process_init, set up the assocaition shared keys as 719 * necessary so that we can potentially authenticate the ACK 720 */ 721 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 722 if (error) 723 goto nomem_init; 724 725 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 726 * is supposed to be authenticated and we have to do delayed 727 * authentication. We've just recreated the association using 728 * the information in the cookie and now it's much easier to 729 * do the authentication. 730 */ 731 if (chunk->auth_chunk) { 732 struct sctp_chunk auth; 733 sctp_ierror_t ret; 734 735 /* set-up our fake chunk so that we can process it */ 736 auth.skb = chunk->auth_chunk; 737 auth.asoc = chunk->asoc; 738 auth.sctp_hdr = chunk->sctp_hdr; 739 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 740 sizeof(sctp_chunkhdr_t)); 741 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 742 auth.transport = chunk->transport; 743 744 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth); 745 746 /* We can now safely free the auth_chunk clone */ 747 kfree_skb(chunk->auth_chunk); 748 749 if (ret != SCTP_IERROR_NO_ERROR) { 750 sctp_association_free(new_asoc); 751 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 752 } 753 } 754 755 repl = sctp_make_cookie_ack(new_asoc, chunk); 756 if (!repl) 757 goto nomem_init; 758 759 /* RFC 2960 5.1 Normal Establishment of an Association 760 * 761 * D) IMPLEMENTATION NOTE: An implementation may choose to 762 * send the Communication Up notification to the SCTP user 763 * upon reception of a valid COOKIE ECHO chunk. 764 */ 765 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 766 new_asoc->c.sinit_num_ostreams, 767 new_asoc->c.sinit_max_instreams, 768 NULL, GFP_ATOMIC); 769 if (!ev) 770 goto nomem_ev; 771 772 /* Sockets API Draft Section 5.3.1.6 773 * When a peer sends a Adaptation Layer Indication parameter , SCTP 774 * delivers this notification to inform the application that of the 775 * peers requested adaptation layer. 776 */ 777 if (new_asoc->peer.adaptation_ind) { 778 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 779 GFP_ATOMIC); 780 if (!ai_ev) 781 goto nomem_aiev; 782 } 783 784 /* Add all the state machine commands now since we've created 785 * everything. This way we don't introduce memory corruptions 786 * during side-effect processing and correclty count established 787 * associations. 788 */ 789 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 790 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 791 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 792 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 793 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 794 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 795 796 if (new_asoc->autoclose) 797 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 798 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 799 800 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 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 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 889 890 /* It may also notify its ULP about the successful 891 * establishment of the association with a Communication Up 892 * notification (see Section 10). 893 */ 894 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 895 0, asoc->c.sinit_num_ostreams, 896 asoc->c.sinit_max_instreams, 897 NULL, GFP_ATOMIC); 898 899 if (!ev) 900 goto nomem; 901 902 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 903 904 /* Sockets API Draft Section 5.3.1.6 905 * When a peer sends a Adaptation Layer Indication parameter , SCTP 906 * delivers this notification to inform the application that of the 907 * peers requested adaptation layer. 908 */ 909 if (asoc->peer.adaptation_ind) { 910 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 911 if (!ev) 912 goto nomem; 913 914 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 915 SCTP_ULPEVENT(ev)); 916 } 917 918 return SCTP_DISPOSITION_CONSUME; 919 nomem: 920 return SCTP_DISPOSITION_NOMEM; 921 } 922 923 /* Generate and sendout a heartbeat packet. */ 924 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 925 const struct sctp_association *asoc, 926 const sctp_subtype_t type, 927 void *arg, 928 sctp_cmd_seq_t *commands) 929 { 930 struct sctp_transport *transport = (struct sctp_transport *) arg; 931 struct sctp_chunk *reply; 932 sctp_sender_hb_info_t hbinfo; 933 size_t paylen = 0; 934 935 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; 936 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); 937 hbinfo.daddr = transport->ipaddr; 938 hbinfo.sent_at = jiffies; 939 hbinfo.hb_nonce = transport->hb_nonce; 940 941 /* Send a heartbeat to our peer. */ 942 paylen = sizeof(sctp_sender_hb_info_t); 943 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); 944 if (!reply) 945 return SCTP_DISPOSITION_NOMEM; 946 947 /* Set rto_pending indicating that an RTT measurement 948 * is started with this heartbeat chunk. 949 */ 950 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 951 SCTP_TRANSPORT(transport)); 952 953 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 954 return SCTP_DISPOSITION_CONSUME; 955 } 956 957 /* Generate a HEARTBEAT packet on the given transport. */ 958 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 959 const struct sctp_association *asoc, 960 const sctp_subtype_t type, 961 void *arg, 962 sctp_cmd_seq_t *commands) 963 { 964 struct sctp_transport *transport = (struct sctp_transport *) arg; 965 966 if (asoc->overall_error_count > asoc->max_retrans) { 967 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 968 SCTP_ERROR(ETIMEDOUT)); 969 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 970 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 971 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 972 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 973 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 974 return SCTP_DISPOSITION_DELETE_TCB; 975 } 976 977 /* Section 3.3.5. 978 * The Sender-specific Heartbeat Info field should normally include 979 * information about the sender's current time when this HEARTBEAT 980 * chunk is sent and the destination transport address to which this 981 * HEARTBEAT is sent (see Section 8.3). 982 */ 983 984 if (transport->param_flags & SPP_HB_ENABLE) { 985 if (SCTP_DISPOSITION_NOMEM == 986 sctp_sf_heartbeat(ep, asoc, type, arg, 987 commands)) 988 return SCTP_DISPOSITION_NOMEM; 989 /* Set transport error counter and association error counter 990 * when sending heartbeat. 991 */ 992 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 993 SCTP_TRANSPORT(transport)); 994 } 995 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 996 SCTP_TRANSPORT(transport)); 997 998 return SCTP_DISPOSITION_CONSUME; 999 } 1000 1001 /* 1002 * Process an heartbeat request. 1003 * 1004 * Section: 8.3 Path Heartbeat 1005 * The receiver of the HEARTBEAT should immediately respond with a 1006 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1007 * from the received HEARTBEAT chunk. 1008 * 1009 * Verification Tag: 8.5 Verification Tag [Normal verification] 1010 * When receiving an SCTP packet, the endpoint MUST ensure that the 1011 * value in the Verification Tag field of the received SCTP packet 1012 * matches its own Tag. If the received Verification Tag value does not 1013 * match the receiver's own tag value, the receiver shall silently 1014 * discard the packet and shall not process it any further except for 1015 * those cases listed in Section 8.5.1 below. 1016 * 1017 * Inputs 1018 * (endpoint, asoc, chunk) 1019 * 1020 * Outputs 1021 * (asoc, reply_msg, msg_up, timers, counters) 1022 * 1023 * The return value is the disposition of the chunk. 1024 */ 1025 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 1026 const struct sctp_association *asoc, 1027 const sctp_subtype_t type, 1028 void *arg, 1029 sctp_cmd_seq_t *commands) 1030 { 1031 struct sctp_chunk *chunk = arg; 1032 struct sctp_chunk *reply; 1033 size_t paylen = 0; 1034 1035 if (!sctp_vtag_verify(chunk, asoc)) 1036 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1037 1038 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1039 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1040 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1041 commands); 1042 1043 /* 8.3 The receiver of the HEARTBEAT should immediately 1044 * respond with a HEARTBEAT ACK that contains the Heartbeat 1045 * Information field copied from the received HEARTBEAT chunk. 1046 */ 1047 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1048 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1049 if (!pskb_pull(chunk->skb, paylen)) 1050 goto nomem; 1051 1052 reply = sctp_make_heartbeat_ack(asoc, chunk, 1053 chunk->subh.hb_hdr, paylen); 1054 if (!reply) 1055 goto nomem; 1056 1057 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1058 return SCTP_DISPOSITION_CONSUME; 1059 1060 nomem: 1061 return SCTP_DISPOSITION_NOMEM; 1062 } 1063 1064 /* 1065 * Process the returning HEARTBEAT ACK. 1066 * 1067 * Section: 8.3 Path Heartbeat 1068 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1069 * should clear the error counter of the destination transport 1070 * address to which the HEARTBEAT was sent, and mark the destination 1071 * transport address as active if it is not so marked. The endpoint may 1072 * optionally report to the upper layer when an inactive destination 1073 * address is marked as active due to the reception of the latest 1074 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1075 * clear the association overall error count as well (as defined 1076 * in section 8.1). 1077 * 1078 * The receiver of the HEARTBEAT ACK should also perform an RTT 1079 * measurement for that destination transport address using the time 1080 * value carried in the HEARTBEAT ACK chunk. 1081 * 1082 * Verification Tag: 8.5 Verification Tag [Normal verification] 1083 * 1084 * Inputs 1085 * (endpoint, asoc, chunk) 1086 * 1087 * Outputs 1088 * (asoc, reply_msg, msg_up, timers, counters) 1089 * 1090 * The return value is the disposition of the chunk. 1091 */ 1092 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 1093 const struct sctp_association *asoc, 1094 const sctp_subtype_t type, 1095 void *arg, 1096 sctp_cmd_seq_t *commands) 1097 { 1098 struct sctp_chunk *chunk = arg; 1099 union sctp_addr from_addr; 1100 struct sctp_transport *link; 1101 sctp_sender_hb_info_t *hbinfo; 1102 unsigned long max_interval; 1103 1104 if (!sctp_vtag_verify(chunk, asoc)) 1105 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1106 1107 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1108 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1109 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1110 commands); 1111 1112 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1113 /* Make sure that the length of the parameter is what we expect */ 1114 if (ntohs(hbinfo->param_hdr.length) != 1115 sizeof(sctp_sender_hb_info_t)) { 1116 return SCTP_DISPOSITION_DISCARD; 1117 } 1118 1119 from_addr = hbinfo->daddr; 1120 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1121 1122 /* This should never happen, but lets log it if so. */ 1123 if (unlikely(!link)) { 1124 if (from_addr.sa.sa_family == AF_INET6) { 1125 if (net_ratelimit()) 1126 printk(KERN_WARNING 1127 "%s association %p could not find address " 1128 NIP6_FMT "\n", 1129 __FUNCTION__, 1130 asoc, 1131 NIP6(from_addr.v6.sin6_addr)); 1132 } else { 1133 if (net_ratelimit()) 1134 printk(KERN_WARNING 1135 "%s association %p could not find address " 1136 NIPQUAD_FMT "\n", 1137 __FUNCTION__, 1138 asoc, 1139 NIPQUAD(from_addr.v4.sin_addr.s_addr)); 1140 } 1141 return SCTP_DISPOSITION_DISCARD; 1142 } 1143 1144 /* Validate the 64-bit random nonce. */ 1145 if (hbinfo->hb_nonce != link->hb_nonce) 1146 return SCTP_DISPOSITION_DISCARD; 1147 1148 max_interval = link->hbinterval + link->rto; 1149 1150 /* Check if the timestamp looks valid. */ 1151 if (time_after(hbinfo->sent_at, jiffies) || 1152 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1153 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp " 1154 "received for transport: %p\n", 1155 __FUNCTION__, link); 1156 return SCTP_DISPOSITION_DISCARD; 1157 } 1158 1159 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1160 * the HEARTBEAT should clear the error counter of the 1161 * destination transport address to which the HEARTBEAT was 1162 * sent and mark the destination transport address as active if 1163 * it is not so marked. 1164 */ 1165 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1166 1167 return SCTP_DISPOSITION_CONSUME; 1168 } 1169 1170 /* Helper function to send out an abort for the restart 1171 * condition. 1172 */ 1173 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1174 struct sctp_chunk *init, 1175 sctp_cmd_seq_t *commands) 1176 { 1177 int len; 1178 struct sctp_packet *pkt; 1179 union sctp_addr_param *addrparm; 1180 struct sctp_errhdr *errhdr; 1181 struct sctp_endpoint *ep; 1182 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1183 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1184 1185 /* Build the error on the stack. We are way to malloc crazy 1186 * throughout the code today. 1187 */ 1188 errhdr = (struct sctp_errhdr *)buffer; 1189 addrparm = (union sctp_addr_param *)errhdr->variable; 1190 1191 /* Copy into a parm format. */ 1192 len = af->to_addr_param(ssa, addrparm); 1193 len += sizeof(sctp_errhdr_t); 1194 1195 errhdr->cause = SCTP_ERROR_RESTART; 1196 errhdr->length = htons(len); 1197 1198 /* Assign to the control socket. */ 1199 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1200 1201 /* Association is NULL since this may be a restart attack and we 1202 * want to send back the attacker's vtag. 1203 */ 1204 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1205 1206 if (!pkt) 1207 goto out; 1208 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1209 1210 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1211 1212 /* Discard the rest of the inbound packet. */ 1213 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1214 1215 out: 1216 /* Even if there is no memory, treat as a failure so 1217 * the packet will get dropped. 1218 */ 1219 return 0; 1220 } 1221 1222 /* A restart is occurring, check to make sure no new addresses 1223 * are being added as we may be under a takeover attack. 1224 */ 1225 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1226 const struct sctp_association *asoc, 1227 struct sctp_chunk *init, 1228 sctp_cmd_seq_t *commands) 1229 { 1230 struct sctp_transport *new_addr, *addr; 1231 struct list_head *pos, *pos2; 1232 int found; 1233 1234 /* Implementor's Guide - Sectin 5.2.2 1235 * ... 1236 * Before responding the endpoint MUST check to see if the 1237 * unexpected INIT adds new addresses to the association. If new 1238 * addresses are added to the association, the endpoint MUST respond 1239 * with an ABORT.. 1240 */ 1241 1242 /* Search through all current addresses and make sure 1243 * we aren't adding any new ones. 1244 */ 1245 new_addr = NULL; 1246 found = 0; 1247 1248 list_for_each(pos, &new_asoc->peer.transport_addr_list) { 1249 new_addr = list_entry(pos, struct sctp_transport, transports); 1250 found = 0; 1251 list_for_each(pos2, &asoc->peer.transport_addr_list) { 1252 addr = list_entry(pos2, struct sctp_transport, 1253 transports); 1254 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1255 &addr->ipaddr)) { 1256 found = 1; 1257 break; 1258 } 1259 } 1260 if (!found) 1261 break; 1262 } 1263 1264 /* If a new address was added, ABORT the sender. */ 1265 if (!found && new_addr) { 1266 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1267 } 1268 1269 /* Return success if all addresses were found. */ 1270 return found; 1271 } 1272 1273 /* Populate the verification/tie tags based on overlapping INIT 1274 * scenario. 1275 * 1276 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1277 */ 1278 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1279 const struct sctp_association *asoc) 1280 { 1281 switch (asoc->state) { 1282 1283 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1284 1285 case SCTP_STATE_COOKIE_WAIT: 1286 new_asoc->c.my_vtag = asoc->c.my_vtag; 1287 new_asoc->c.my_ttag = asoc->c.my_vtag; 1288 new_asoc->c.peer_ttag = 0; 1289 break; 1290 1291 case SCTP_STATE_COOKIE_ECHOED: 1292 new_asoc->c.my_vtag = asoc->c.my_vtag; 1293 new_asoc->c.my_ttag = asoc->c.my_vtag; 1294 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1295 break; 1296 1297 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1298 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1299 */ 1300 default: 1301 new_asoc->c.my_ttag = asoc->c.my_vtag; 1302 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1303 break; 1304 } 1305 1306 /* Other parameters for the endpoint SHOULD be copied from the 1307 * existing parameters of the association (e.g. number of 1308 * outbound streams) into the INIT ACK and cookie. 1309 */ 1310 new_asoc->rwnd = asoc->rwnd; 1311 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1312 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1313 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1314 } 1315 1316 /* 1317 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1318 * handling action. 1319 * 1320 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1321 * 1322 * Returns value representing action to be taken. These action values 1323 * correspond to Action/Description values in RFC 2960, Table 2. 1324 */ 1325 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1326 const struct sctp_association *asoc) 1327 { 1328 /* In this case, the peer may have restarted. */ 1329 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1330 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1331 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1332 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1333 return 'A'; 1334 1335 /* Collision case B. */ 1336 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1337 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1338 (0 == asoc->c.peer_vtag))) { 1339 return 'B'; 1340 } 1341 1342 /* Collision case D. */ 1343 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1344 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1345 return 'D'; 1346 1347 /* Collision case C. */ 1348 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1349 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1350 (0 == new_asoc->c.my_ttag) && 1351 (0 == new_asoc->c.peer_ttag)) 1352 return 'C'; 1353 1354 /* No match to any of the special cases; discard this packet. */ 1355 return 'E'; 1356 } 1357 1358 /* Common helper routine for both duplicate and simulataneous INIT 1359 * chunk handling. 1360 */ 1361 static sctp_disposition_t sctp_sf_do_unexpected_init( 1362 const struct sctp_endpoint *ep, 1363 const struct sctp_association *asoc, 1364 const sctp_subtype_t type, 1365 void *arg, sctp_cmd_seq_t *commands) 1366 { 1367 sctp_disposition_t retval; 1368 struct sctp_chunk *chunk = arg; 1369 struct sctp_chunk *repl; 1370 struct sctp_association *new_asoc; 1371 struct sctp_chunk *err_chunk; 1372 struct sctp_packet *packet; 1373 sctp_unrecognized_param_t *unk_param; 1374 int len; 1375 1376 /* 6.10 Bundling 1377 * An endpoint MUST NOT bundle INIT, INIT ACK or 1378 * SHUTDOWN COMPLETE with any other chunks. 1379 * 1380 * IG Section 2.11.2 1381 * Furthermore, we require that the receiver of an INIT chunk MUST 1382 * enforce these rules by silently discarding an arriving packet 1383 * with an INIT chunk that is bundled with other chunks. 1384 */ 1385 if (!chunk->singleton) 1386 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1387 1388 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1389 * Tag. 1390 */ 1391 if (chunk->sctp_hdr->vtag != 0) 1392 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1393 1394 /* Make sure that the INIT chunk has a valid length. 1395 * In this case, we generate a protocol violation since we have 1396 * an association established. 1397 */ 1398 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1399 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1400 commands); 1401 /* Grab the INIT header. */ 1402 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1403 1404 /* Tag the variable length parameters. */ 1405 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1406 1407 /* Verify the INIT chunk before processing it. */ 1408 err_chunk = NULL; 1409 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1410 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1411 &err_chunk)) { 1412 /* This chunk contains fatal error. It is to be discarded. 1413 * Send an ABORT, with causes if there is any. 1414 */ 1415 if (err_chunk) { 1416 packet = sctp_abort_pkt_new(ep, asoc, arg, 1417 (__u8 *)(err_chunk->chunk_hdr) + 1418 sizeof(sctp_chunkhdr_t), 1419 ntohs(err_chunk->chunk_hdr->length) - 1420 sizeof(sctp_chunkhdr_t)); 1421 1422 if (packet) { 1423 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1424 SCTP_PACKET(packet)); 1425 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1426 retval = SCTP_DISPOSITION_CONSUME; 1427 } else { 1428 retval = SCTP_DISPOSITION_NOMEM; 1429 } 1430 goto cleanup; 1431 } else { 1432 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1433 commands); 1434 } 1435 } 1436 1437 /* 1438 * Other parameters for the endpoint SHOULD be copied from the 1439 * existing parameters of the association (e.g. number of 1440 * outbound streams) into the INIT ACK and cookie. 1441 * FIXME: We are copying parameters from the endpoint not the 1442 * association. 1443 */ 1444 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1445 if (!new_asoc) 1446 goto nomem; 1447 1448 /* In the outbound INIT ACK the endpoint MUST copy its current 1449 * Verification Tag and Peers Verification tag into a reserved 1450 * place (local tie-tag and per tie-tag) within the state cookie. 1451 */ 1452 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1453 sctp_source(chunk), 1454 (sctp_init_chunk_t *)chunk->chunk_hdr, 1455 GFP_ATOMIC)) 1456 goto nomem; 1457 1458 /* Make sure no new addresses are being added during the 1459 * restart. Do not do this check for COOKIE-WAIT state, 1460 * since there are no peer addresses to check against. 1461 * Upon return an ABORT will have been sent if needed. 1462 */ 1463 if (!sctp_state(asoc, COOKIE_WAIT)) { 1464 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1465 commands)) { 1466 retval = SCTP_DISPOSITION_CONSUME; 1467 goto nomem_retval; 1468 } 1469 } 1470 1471 sctp_tietags_populate(new_asoc, asoc); 1472 1473 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1474 1475 /* If there are errors need to be reported for unknown parameters, 1476 * make sure to reserve enough room in the INIT ACK for them. 1477 */ 1478 len = 0; 1479 if (err_chunk) { 1480 len = ntohs(err_chunk->chunk_hdr->length) - 1481 sizeof(sctp_chunkhdr_t); 1482 } 1483 1484 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 1485 goto nomem; 1486 1487 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1488 if (!repl) 1489 goto nomem; 1490 1491 /* If there are errors need to be reported for unknown parameters, 1492 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1493 * parameter. 1494 */ 1495 if (err_chunk) { 1496 /* Get the "Unrecognized parameter" parameter(s) out of the 1497 * ERROR chunk generated by sctp_verify_init(). Since the 1498 * error cause code for "unknown parameter" and the 1499 * "Unrecognized parameter" type is the same, we can 1500 * construct the parameters in INIT ACK by copying the 1501 * ERROR causes over. 1502 */ 1503 unk_param = (sctp_unrecognized_param_t *) 1504 ((__u8 *)(err_chunk->chunk_hdr) + 1505 sizeof(sctp_chunkhdr_t)); 1506 /* Replace the cause code with the "Unrecognized parameter" 1507 * parameter type. 1508 */ 1509 sctp_addto_chunk(repl, len, unk_param); 1510 } 1511 1512 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1513 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1514 1515 /* 1516 * Note: After sending out INIT ACK with the State Cookie parameter, 1517 * "Z" MUST NOT allocate any resources for this new association. 1518 * Otherwise, "Z" will be vulnerable to resource attacks. 1519 */ 1520 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1521 retval = SCTP_DISPOSITION_CONSUME; 1522 1523 return retval; 1524 1525 nomem: 1526 retval = SCTP_DISPOSITION_NOMEM; 1527 nomem_retval: 1528 if (new_asoc) 1529 sctp_association_free(new_asoc); 1530 cleanup: 1531 if (err_chunk) 1532 sctp_chunk_free(err_chunk); 1533 return retval; 1534 } 1535 1536 /* 1537 * Handle simultanous INIT. 1538 * This means we started an INIT and then we got an INIT request from 1539 * our peer. 1540 * 1541 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1542 * This usually indicates an initialization collision, i.e., each 1543 * endpoint is attempting, at about the same time, to establish an 1544 * association with the other endpoint. 1545 * 1546 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1547 * endpoint MUST respond with an INIT ACK using the same parameters it 1548 * sent in its original INIT chunk (including its Verification Tag, 1549 * unchanged). These original parameters are combined with those from the 1550 * newly received INIT chunk. The endpoint shall also generate a State 1551 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1552 * INIT to calculate the State Cookie. 1553 * 1554 * After that, the endpoint MUST NOT change its state, the T1-init 1555 * timer shall be left running and the corresponding TCB MUST NOT be 1556 * destroyed. The normal procedures for handling State Cookies when 1557 * a TCB exists will resolve the duplicate INITs to a single association. 1558 * 1559 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1560 * its Tie-Tags with the Tag information of itself and its peer (see 1561 * section 5.2.2 for a description of the Tie-Tags). 1562 * 1563 * Verification Tag: Not explicit, but an INIT can not have a valid 1564 * verification tag, so we skip the check. 1565 * 1566 * Inputs 1567 * (endpoint, asoc, chunk) 1568 * 1569 * Outputs 1570 * (asoc, reply_msg, msg_up, timers, counters) 1571 * 1572 * The return value is the disposition of the chunk. 1573 */ 1574 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1575 const struct sctp_association *asoc, 1576 const sctp_subtype_t type, 1577 void *arg, 1578 sctp_cmd_seq_t *commands) 1579 { 1580 /* Call helper to do the real work for both simulataneous and 1581 * duplicate INIT chunk handling. 1582 */ 1583 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1584 } 1585 1586 /* 1587 * Handle duplicated INIT messages. These are usually delayed 1588 * restransmissions. 1589 * 1590 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1591 * COOKIE-ECHOED and COOKIE-WAIT 1592 * 1593 * Unless otherwise stated, upon reception of an unexpected INIT for 1594 * this association, the endpoint shall generate an INIT ACK with a 1595 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1596 * current Verification Tag and peer's Verification Tag into a reserved 1597 * place within the state cookie. We shall refer to these locations as 1598 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1599 * containing this INIT ACK MUST carry a Verification Tag value equal to 1600 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1601 * MUST contain a new Initiation Tag (randomly generated see Section 1602 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1603 * existing parameters of the association (e.g. number of outbound 1604 * streams) into the INIT ACK and cookie. 1605 * 1606 * After sending out the INIT ACK, the endpoint shall take no further 1607 * actions, i.e., the existing association, including its current state, 1608 * and the corresponding TCB MUST NOT be changed. 1609 * 1610 * Note: Only when a TCB exists and the association is not in a COOKIE- 1611 * WAIT state are the Tie-Tags populated. For a normal association INIT 1612 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1613 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1614 * State Cookie are populated as specified in section 5.2.1. 1615 * 1616 * Verification Tag: Not specified, but an INIT has no way of knowing 1617 * what the verification tag could be, so we ignore it. 1618 * 1619 * Inputs 1620 * (endpoint, asoc, chunk) 1621 * 1622 * Outputs 1623 * (asoc, reply_msg, msg_up, timers, counters) 1624 * 1625 * The return value is the disposition of the chunk. 1626 */ 1627 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1628 const struct sctp_association *asoc, 1629 const sctp_subtype_t type, 1630 void *arg, 1631 sctp_cmd_seq_t *commands) 1632 { 1633 /* Call helper to do the real work for both simulataneous and 1634 * duplicate INIT chunk handling. 1635 */ 1636 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1637 } 1638 1639 1640 /* 1641 * Unexpected INIT-ACK handler. 1642 * 1643 * Section 5.2.3 1644 * If an INIT ACK received by an endpoint in any state other than the 1645 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1646 * An unexpected INIT ACK usually indicates the processing of an old or 1647 * duplicated INIT chunk. 1648 */ 1649 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep, 1650 const struct sctp_association *asoc, 1651 const sctp_subtype_t type, 1652 void *arg, sctp_cmd_seq_t *commands) 1653 { 1654 /* Per the above section, we'll discard the chunk if we have an 1655 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1656 */ 1657 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 1658 return sctp_sf_ootb(ep, asoc, type, arg, commands); 1659 else 1660 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 1661 } 1662 1663 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1664 * 1665 * Section 5.2.4 1666 * A) In this case, the peer may have restarted. 1667 */ 1668 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1669 const struct sctp_association *asoc, 1670 struct sctp_chunk *chunk, 1671 sctp_cmd_seq_t *commands, 1672 struct sctp_association *new_asoc) 1673 { 1674 sctp_init_chunk_t *peer_init; 1675 struct sctp_ulpevent *ev; 1676 struct sctp_chunk *repl; 1677 struct sctp_chunk *err; 1678 sctp_disposition_t disposition; 1679 1680 /* new_asoc is a brand-new association, so these are not yet 1681 * side effects--it is safe to run them here. 1682 */ 1683 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1684 1685 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1686 sctp_source(chunk), peer_init, 1687 GFP_ATOMIC)) 1688 goto nomem; 1689 1690 /* Make sure no new addresses are being added during the 1691 * restart. Though this is a pretty complicated attack 1692 * since you'd have to get inside the cookie. 1693 */ 1694 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1695 return SCTP_DISPOSITION_CONSUME; 1696 } 1697 1698 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1699 * the peer has restarted (Action A), it MUST NOT setup a new 1700 * association but instead resend the SHUTDOWN ACK and send an ERROR 1701 * chunk with a "Cookie Received while Shutting Down" error cause to 1702 * its peer. 1703 */ 1704 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1705 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1706 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1707 chunk, commands); 1708 if (SCTP_DISPOSITION_NOMEM == disposition) 1709 goto nomem; 1710 1711 err = sctp_make_op_error(asoc, chunk, 1712 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1713 NULL, 0); 1714 if (err) 1715 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1716 SCTP_CHUNK(err)); 1717 1718 return SCTP_DISPOSITION_CONSUME; 1719 } 1720 1721 /* For now, fail any unsent/unacked data. Consider the optional 1722 * choice of resending of this data. 1723 */ 1724 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1725 1726 repl = sctp_make_cookie_ack(new_asoc, chunk); 1727 if (!repl) 1728 goto nomem; 1729 1730 /* Report association restart to upper layer. */ 1731 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1732 new_asoc->c.sinit_num_ostreams, 1733 new_asoc->c.sinit_max_instreams, 1734 NULL, GFP_ATOMIC); 1735 if (!ev) 1736 goto nomem_ev; 1737 1738 /* Update the content of current association. */ 1739 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1740 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1741 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1742 return SCTP_DISPOSITION_CONSUME; 1743 1744 nomem_ev: 1745 sctp_chunk_free(repl); 1746 nomem: 1747 return SCTP_DISPOSITION_NOMEM; 1748 } 1749 1750 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1751 * 1752 * Section 5.2.4 1753 * B) In this case, both sides may be attempting to start an association 1754 * at about the same time but the peer endpoint started its INIT 1755 * after responding to the local endpoint's INIT 1756 */ 1757 /* This case represents an initialization collision. */ 1758 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1759 const struct sctp_association *asoc, 1760 struct sctp_chunk *chunk, 1761 sctp_cmd_seq_t *commands, 1762 struct sctp_association *new_asoc) 1763 { 1764 sctp_init_chunk_t *peer_init; 1765 struct sctp_chunk *repl; 1766 1767 /* new_asoc is a brand-new association, so these are not yet 1768 * side effects--it is safe to run them here. 1769 */ 1770 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1771 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1772 sctp_source(chunk), peer_init, 1773 GFP_ATOMIC)) 1774 goto nomem; 1775 1776 /* Update the content of current association. */ 1777 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1778 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1779 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1780 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1781 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1782 1783 repl = sctp_make_cookie_ack(new_asoc, chunk); 1784 if (!repl) 1785 goto nomem; 1786 1787 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1788 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1789 1790 /* RFC 2960 5.1 Normal Establishment of an Association 1791 * 1792 * D) IMPLEMENTATION NOTE: An implementation may choose to 1793 * send the Communication Up notification to the SCTP user 1794 * upon reception of a valid COOKIE ECHO chunk. 1795 * 1796 * Sadly, this needs to be implemented as a side-effect, because 1797 * we are not guaranteed to have set the association id of the real 1798 * association and so these notifications need to be delayed until 1799 * the association id is allocated. 1800 */ 1801 1802 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1803 1804 /* Sockets API Draft Section 5.3.1.6 1805 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1806 * delivers this notification to inform the application that of the 1807 * peers requested adaptation layer. 1808 * 1809 * This also needs to be done as a side effect for the same reason as 1810 * above. 1811 */ 1812 if (asoc->peer.adaptation_ind) 1813 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1814 1815 return SCTP_DISPOSITION_CONSUME; 1816 1817 nomem: 1818 return SCTP_DISPOSITION_NOMEM; 1819 } 1820 1821 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1822 * 1823 * Section 5.2.4 1824 * C) In this case, the local endpoint's cookie has arrived late. 1825 * Before it arrived, the local endpoint sent an INIT and received an 1826 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1827 * but a new tag of its own. 1828 */ 1829 /* This case represents an initialization collision. */ 1830 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1831 const struct sctp_association *asoc, 1832 struct sctp_chunk *chunk, 1833 sctp_cmd_seq_t *commands, 1834 struct sctp_association *new_asoc) 1835 { 1836 /* The cookie should be silently discarded. 1837 * The endpoint SHOULD NOT change states and should leave 1838 * any timers running. 1839 */ 1840 return SCTP_DISPOSITION_DISCARD; 1841 } 1842 1843 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1844 * 1845 * Section 5.2.4 1846 * 1847 * D) When both local and remote tags match the endpoint should always 1848 * enter the ESTABLISHED state, if it has not already done so. 1849 */ 1850 /* This case represents an initialization collision. */ 1851 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1852 const struct sctp_association *asoc, 1853 struct sctp_chunk *chunk, 1854 sctp_cmd_seq_t *commands, 1855 struct sctp_association *new_asoc) 1856 { 1857 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1858 struct sctp_chunk *repl; 1859 1860 /* Clarification from Implementor's Guide: 1861 * D) When both local and remote tags match the endpoint should 1862 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1863 * It should stop any cookie timer that may be running and send 1864 * a COOKIE ACK. 1865 */ 1866 1867 /* Don't accidentally move back into established state. */ 1868 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1869 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1870 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1871 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1872 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1873 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1874 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1875 SCTP_NULL()); 1876 1877 /* RFC 2960 5.1 Normal Establishment of an Association 1878 * 1879 * D) IMPLEMENTATION NOTE: An implementation may choose 1880 * to send the Communication Up notification to the 1881 * SCTP user upon reception of a valid COOKIE 1882 * ECHO chunk. 1883 */ 1884 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1885 SCTP_COMM_UP, 0, 1886 asoc->c.sinit_num_ostreams, 1887 asoc->c.sinit_max_instreams, 1888 NULL, GFP_ATOMIC); 1889 if (!ev) 1890 goto nomem; 1891 1892 /* Sockets API Draft Section 5.3.1.6 1893 * When a peer sends a Adaptation Layer Indication parameter, 1894 * SCTP delivers this notification to inform the application 1895 * that of the peers requested adaptation layer. 1896 */ 1897 if (asoc->peer.adaptation_ind) { 1898 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1899 GFP_ATOMIC); 1900 if (!ai_ev) 1901 goto nomem; 1902 1903 } 1904 } 1905 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1906 1907 repl = sctp_make_cookie_ack(new_asoc, chunk); 1908 if (!repl) 1909 goto nomem; 1910 1911 if (ev) 1912 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1913 SCTP_ULPEVENT(ev)); 1914 if (ai_ev) 1915 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1916 SCTP_ULPEVENT(ai_ev)); 1917 1918 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1919 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1920 1921 return SCTP_DISPOSITION_CONSUME; 1922 1923 nomem: 1924 if (ai_ev) 1925 sctp_ulpevent_free(ai_ev); 1926 if (ev) 1927 sctp_ulpevent_free(ev); 1928 return SCTP_DISPOSITION_NOMEM; 1929 } 1930 1931 /* 1932 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1933 * chunk was retransmitted and then delayed in the network. 1934 * 1935 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1936 * 1937 * Verification Tag: None. Do cookie validation. 1938 * 1939 * Inputs 1940 * (endpoint, asoc, chunk) 1941 * 1942 * Outputs 1943 * (asoc, reply_msg, msg_up, timers, counters) 1944 * 1945 * The return value is the disposition of the chunk. 1946 */ 1947 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1948 const struct sctp_association *asoc, 1949 const sctp_subtype_t type, 1950 void *arg, 1951 sctp_cmd_seq_t *commands) 1952 { 1953 sctp_disposition_t retval; 1954 struct sctp_chunk *chunk = arg; 1955 struct sctp_association *new_asoc; 1956 int error = 0; 1957 char action; 1958 struct sctp_chunk *err_chk_p; 1959 1960 /* Make sure that the chunk has a valid length from the protocol 1961 * perspective. In this case check to make sure we have at least 1962 * enough for the chunk header. Cookie length verification is 1963 * done later. 1964 */ 1965 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1966 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1967 commands); 1968 1969 /* "Decode" the chunk. We have no optional parameters so we 1970 * are in good shape. 1971 */ 1972 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1973 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1974 sizeof(sctp_chunkhdr_t))) 1975 goto nomem; 1976 1977 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1978 * of a duplicate COOKIE ECHO match the Verification Tags of the 1979 * current association, consider the State Cookie valid even if 1980 * the lifespan is exceeded. 1981 */ 1982 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1983 &err_chk_p); 1984 1985 /* FIXME: 1986 * If the re-build failed, what is the proper error path 1987 * from here? 1988 * 1989 * [We should abort the association. --piggy] 1990 */ 1991 if (!new_asoc) { 1992 /* FIXME: Several errors are possible. A bad cookie should 1993 * be silently discarded, but think about logging it too. 1994 */ 1995 switch (error) { 1996 case -SCTP_IERROR_NOMEM: 1997 goto nomem; 1998 1999 case -SCTP_IERROR_STALE_COOKIE: 2000 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 2001 err_chk_p); 2002 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2003 case -SCTP_IERROR_BAD_SIG: 2004 default: 2005 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2006 } 2007 } 2008 2009 /* Compare the tie_tag in cookie with the verification tag of 2010 * current association. 2011 */ 2012 action = sctp_tietags_compare(new_asoc, asoc); 2013 2014 switch (action) { 2015 case 'A': /* Association restart. */ 2016 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 2017 new_asoc); 2018 break; 2019 2020 case 'B': /* Collision case B. */ 2021 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 2022 new_asoc); 2023 break; 2024 2025 case 'C': /* Collision case C. */ 2026 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 2027 new_asoc); 2028 break; 2029 2030 case 'D': /* Collision case D. */ 2031 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 2032 new_asoc); 2033 break; 2034 2035 default: /* Discard packet for all others. */ 2036 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2037 break; 2038 } 2039 2040 /* Delete the tempory new association. */ 2041 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2042 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2043 2044 return retval; 2045 2046 nomem: 2047 return SCTP_DISPOSITION_NOMEM; 2048 } 2049 2050 /* 2051 * Process an ABORT. (SHUTDOWN-PENDING state) 2052 * 2053 * See sctp_sf_do_9_1_abort(). 2054 */ 2055 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2056 const struct sctp_endpoint *ep, 2057 const struct sctp_association *asoc, 2058 const sctp_subtype_t type, 2059 void *arg, 2060 sctp_cmd_seq_t *commands) 2061 { 2062 struct sctp_chunk *chunk = arg; 2063 2064 if (!sctp_vtag_verify_either(chunk, asoc)) 2065 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2066 2067 /* Make sure that the ABORT chunk has a valid length. 2068 * Since this is an ABORT chunk, we have to discard it 2069 * because of the following text: 2070 * RFC 2960, Section 3.3.7 2071 * If an endpoint receives an ABORT with a format error or for an 2072 * association that doesn't exist, it MUST silently discard it. 2073 * Becasue the length is "invalid", we can't really discard just 2074 * as we do not know its true length. So, to be safe, discard the 2075 * packet. 2076 */ 2077 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2078 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2079 2080 /* ADD-IP: Special case for ABORT chunks 2081 * F4) One special consideration is that ABORT Chunks arriving 2082 * destined to the IP address being deleted MUST be 2083 * ignored (see Section 5.3.1 for further details). 2084 */ 2085 if (SCTP_ADDR_DEL == 2086 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2087 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2088 2089 /* Stop the T5-shutdown guard timer. */ 2090 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2091 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2092 2093 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2094 } 2095 2096 /* 2097 * Process an ABORT. (SHUTDOWN-SENT state) 2098 * 2099 * See sctp_sf_do_9_1_abort(). 2100 */ 2101 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 2102 const struct sctp_association *asoc, 2103 const sctp_subtype_t type, 2104 void *arg, 2105 sctp_cmd_seq_t *commands) 2106 { 2107 struct sctp_chunk *chunk = arg; 2108 2109 if (!sctp_vtag_verify_either(chunk, asoc)) 2110 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2111 2112 /* Make sure that the ABORT chunk has a valid length. 2113 * Since this is an ABORT chunk, we have to discard it 2114 * because of the following text: 2115 * RFC 2960, Section 3.3.7 2116 * If an endpoint receives an ABORT with a format error or for an 2117 * association that doesn't exist, it MUST silently discard it. 2118 * Becasue the length is "invalid", we can't really discard just 2119 * as we do not know its true length. So, to be safe, discard the 2120 * packet. 2121 */ 2122 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2123 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2124 2125 /* ADD-IP: Special case for ABORT chunks 2126 * F4) One special consideration is that ABORT Chunks arriving 2127 * destined to the IP address being deleted MUST be 2128 * ignored (see Section 5.3.1 for further details). 2129 */ 2130 if (SCTP_ADDR_DEL == 2131 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2132 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2133 2134 /* Stop the T2-shutdown timer. */ 2135 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2136 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2137 2138 /* Stop the T5-shutdown guard timer. */ 2139 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2140 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2141 2142 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2143 } 2144 2145 /* 2146 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2147 * 2148 * See sctp_sf_do_9_1_abort(). 2149 */ 2150 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2151 const struct sctp_endpoint *ep, 2152 const struct sctp_association *asoc, 2153 const sctp_subtype_t type, 2154 void *arg, 2155 sctp_cmd_seq_t *commands) 2156 { 2157 /* The same T2 timer, so we should be able to use 2158 * common function with the SHUTDOWN-SENT state. 2159 */ 2160 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2161 } 2162 2163 /* 2164 * Handle an Error received in COOKIE_ECHOED state. 2165 * 2166 * Only handle the error type of stale COOKIE Error, the other errors will 2167 * be ignored. 2168 * 2169 * Inputs 2170 * (endpoint, asoc, chunk) 2171 * 2172 * Outputs 2173 * (asoc, reply_msg, msg_up, timers, counters) 2174 * 2175 * The return value is the disposition of the chunk. 2176 */ 2177 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2178 const struct sctp_association *asoc, 2179 const sctp_subtype_t type, 2180 void *arg, 2181 sctp_cmd_seq_t *commands) 2182 { 2183 struct sctp_chunk *chunk = arg; 2184 sctp_errhdr_t *err; 2185 2186 if (!sctp_vtag_verify(chunk, asoc)) 2187 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2188 2189 /* Make sure that the ERROR chunk has a valid length. 2190 * The parameter walking depends on this as well. 2191 */ 2192 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2193 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2194 commands); 2195 2196 /* Process the error here */ 2197 /* FUTURE FIXME: When PR-SCTP related and other optional 2198 * parms are emitted, this will have to change to handle multiple 2199 * errors. 2200 */ 2201 sctp_walk_errors(err, chunk->chunk_hdr) { 2202 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2203 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2204 arg, commands); 2205 } 2206 2207 /* It is possible to have malformed error causes, and that 2208 * will cause us to end the walk early. However, since 2209 * we are discarding the packet, there should be no adverse 2210 * affects. 2211 */ 2212 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2213 } 2214 2215 /* 2216 * Handle a Stale COOKIE Error 2217 * 2218 * Section: 5.2.6 Handle Stale COOKIE Error 2219 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2220 * one of the following three alternatives. 2221 * ... 2222 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2223 * Preservative parameter requesting an extension to the lifetime of 2224 * the State Cookie. When calculating the time extension, an 2225 * implementation SHOULD use the RTT information measured based on the 2226 * previous COOKIE ECHO / ERROR exchange, and should add no more 2227 * than 1 second beyond the measured RTT, due to long State Cookie 2228 * lifetimes making the endpoint more subject to a replay attack. 2229 * 2230 * Verification Tag: Not explicit, but safe to ignore. 2231 * 2232 * Inputs 2233 * (endpoint, asoc, chunk) 2234 * 2235 * Outputs 2236 * (asoc, reply_msg, msg_up, timers, counters) 2237 * 2238 * The return value is the disposition of the chunk. 2239 */ 2240 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2241 const struct sctp_association *asoc, 2242 const sctp_subtype_t type, 2243 void *arg, 2244 sctp_cmd_seq_t *commands) 2245 { 2246 struct sctp_chunk *chunk = arg; 2247 time_t stale; 2248 sctp_cookie_preserve_param_t bht; 2249 sctp_errhdr_t *err; 2250 struct sctp_chunk *reply; 2251 struct sctp_bind_addr *bp; 2252 int attempts = asoc->init_err_counter + 1; 2253 2254 if (attempts > asoc->max_init_attempts) { 2255 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2256 SCTP_ERROR(ETIMEDOUT)); 2257 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2258 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2259 return SCTP_DISPOSITION_DELETE_TCB; 2260 } 2261 2262 err = (sctp_errhdr_t *)(chunk->skb->data); 2263 2264 /* When calculating the time extension, an implementation 2265 * SHOULD use the RTT information measured based on the 2266 * previous COOKIE ECHO / ERROR exchange, and should add no 2267 * more than 1 second beyond the measured RTT, due to long 2268 * State Cookie lifetimes making the endpoint more subject to 2269 * a replay attack. 2270 * Measure of Staleness's unit is usec. (1/1000000 sec) 2271 * Suggested Cookie Life-span Increment's unit is msec. 2272 * (1/1000 sec) 2273 * In general, if you use the suggested cookie life, the value 2274 * found in the field of measure of staleness should be doubled 2275 * to give ample time to retransmit the new cookie and thus 2276 * yield a higher probability of success on the reattempt. 2277 */ 2278 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2279 stale = (stale * 2) / 1000; 2280 2281 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2282 bht.param_hdr.length = htons(sizeof(bht)); 2283 bht.lifespan_increment = htonl(stale); 2284 2285 /* Build that new INIT chunk. */ 2286 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2287 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2288 if (!reply) 2289 goto nomem; 2290 2291 sctp_addto_chunk(reply, sizeof(bht), &bht); 2292 2293 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2294 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2295 2296 /* Stop pending T3-rtx and heartbeat timers */ 2297 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2298 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2299 2300 /* Delete non-primary peer ip addresses since we are transitioning 2301 * back to the COOKIE-WAIT state 2302 */ 2303 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2304 2305 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2306 * resend 2307 */ 2308 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2309 SCTP_TRANSPORT(asoc->peer.primary_path)); 2310 2311 /* Cast away the const modifier, as we want to just 2312 * rerun it through as a sideffect. 2313 */ 2314 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2315 2316 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2317 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2318 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2319 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2320 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2321 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2322 2323 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2324 2325 return SCTP_DISPOSITION_CONSUME; 2326 2327 nomem: 2328 return SCTP_DISPOSITION_NOMEM; 2329 } 2330 2331 /* 2332 * Process an ABORT. 2333 * 2334 * Section: 9.1 2335 * After checking the Verification Tag, the receiving endpoint shall 2336 * remove the association from its record, and shall report the 2337 * termination to its upper layer. 2338 * 2339 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2340 * B) Rules for packet carrying ABORT: 2341 * 2342 * - The endpoint shall always fill in the Verification Tag field of the 2343 * outbound packet with the destination endpoint's tag value if it 2344 * is known. 2345 * 2346 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2347 * MUST follow the procedure described in Section 8.4. 2348 * 2349 * - The receiver MUST accept the packet if the Verification Tag 2350 * matches either its own tag, OR the tag of its peer. Otherwise, the 2351 * receiver MUST silently discard the packet and take no further 2352 * action. 2353 * 2354 * Inputs 2355 * (endpoint, asoc, chunk) 2356 * 2357 * Outputs 2358 * (asoc, reply_msg, msg_up, timers, counters) 2359 * 2360 * The return value is the disposition of the chunk. 2361 */ 2362 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2363 const struct sctp_association *asoc, 2364 const sctp_subtype_t type, 2365 void *arg, 2366 sctp_cmd_seq_t *commands) 2367 { 2368 struct sctp_chunk *chunk = arg; 2369 2370 if (!sctp_vtag_verify_either(chunk, asoc)) 2371 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2372 2373 /* Make sure that the ABORT chunk has a valid length. 2374 * Since this is an ABORT chunk, we have to discard it 2375 * because of the following text: 2376 * RFC 2960, Section 3.3.7 2377 * If an endpoint receives an ABORT with a format error or for an 2378 * association that doesn't exist, it MUST silently discard it. 2379 * Becasue the length is "invalid", we can't really discard just 2380 * as we do not know its true length. So, to be safe, discard the 2381 * packet. 2382 */ 2383 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2384 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2385 2386 /* ADD-IP: Special case for ABORT chunks 2387 * F4) One special consideration is that ABORT Chunks arriving 2388 * destined to the IP address being deleted MUST be 2389 * ignored (see Section 5.3.1 for further details). 2390 */ 2391 if (SCTP_ADDR_DEL == 2392 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2393 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2394 2395 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2396 } 2397 2398 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2399 const struct sctp_association *asoc, 2400 const sctp_subtype_t type, 2401 void *arg, 2402 sctp_cmd_seq_t *commands) 2403 { 2404 struct sctp_chunk *chunk = arg; 2405 unsigned len; 2406 __be16 error = SCTP_ERROR_NO_ERROR; 2407 2408 /* See if we have an error cause code in the chunk. */ 2409 len = ntohs(chunk->chunk_hdr->length); 2410 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2411 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2412 2413 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2414 /* ASSOC_FAILED will DELETE_TCB. */ 2415 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2416 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2417 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2418 2419 return SCTP_DISPOSITION_ABORT; 2420 } 2421 2422 /* 2423 * Process an ABORT. (COOKIE-WAIT state) 2424 * 2425 * See sctp_sf_do_9_1_abort() above. 2426 */ 2427 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2428 const struct sctp_association *asoc, 2429 const sctp_subtype_t type, 2430 void *arg, 2431 sctp_cmd_seq_t *commands) 2432 { 2433 struct sctp_chunk *chunk = arg; 2434 unsigned len; 2435 __be16 error = SCTP_ERROR_NO_ERROR; 2436 2437 if (!sctp_vtag_verify_either(chunk, asoc)) 2438 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2439 2440 /* Make sure that the ABORT chunk has a valid length. 2441 * Since this is an ABORT chunk, we have to discard it 2442 * because of the following text: 2443 * RFC 2960, Section 3.3.7 2444 * If an endpoint receives an ABORT with a format error or for an 2445 * association that doesn't exist, it MUST silently discard it. 2446 * Becasue the length is "invalid", we can't really discard just 2447 * as we do not know its true length. So, to be safe, discard the 2448 * packet. 2449 */ 2450 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2451 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2452 2453 /* See if we have an error cause code in the chunk. */ 2454 len = ntohs(chunk->chunk_hdr->length); 2455 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2456 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2457 2458 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, 2459 chunk->transport); 2460 } 2461 2462 /* 2463 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2464 */ 2465 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2466 const struct sctp_association *asoc, 2467 const sctp_subtype_t type, 2468 void *arg, 2469 sctp_cmd_seq_t *commands) 2470 { 2471 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, 2472 ENOPROTOOPT, asoc, 2473 (struct sctp_transport *)arg); 2474 } 2475 2476 /* 2477 * Process an ABORT. (COOKIE-ECHOED state) 2478 */ 2479 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2480 const struct sctp_association *asoc, 2481 const sctp_subtype_t type, 2482 void *arg, 2483 sctp_cmd_seq_t *commands) 2484 { 2485 /* There is a single T1 timer, so we should be able to use 2486 * common function with the COOKIE-WAIT state. 2487 */ 2488 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2489 } 2490 2491 /* 2492 * Stop T1 timer and abort association with "INIT failed". 2493 * 2494 * This is common code called by several sctp_sf_*_abort() functions above. 2495 */ 2496 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2497 __be16 error, int sk_err, 2498 const struct sctp_association *asoc, 2499 struct sctp_transport *transport) 2500 { 2501 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2502 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2503 SCTP_STATE(SCTP_STATE_CLOSED)); 2504 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2505 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2506 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2507 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2508 /* CMD_INIT_FAILED will DELETE_TCB. */ 2509 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2510 SCTP_PERR(error)); 2511 return SCTP_DISPOSITION_ABORT; 2512 } 2513 2514 /* 2515 * sctp_sf_do_9_2_shut 2516 * 2517 * Section: 9.2 2518 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2519 * - enter the SHUTDOWN-RECEIVED state, 2520 * 2521 * - stop accepting new data from its SCTP user 2522 * 2523 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2524 * that all its outstanding DATA chunks have been received by the 2525 * SHUTDOWN sender. 2526 * 2527 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2528 * send a SHUTDOWN in response to a ULP request. And should discard 2529 * subsequent SHUTDOWN chunks. 2530 * 2531 * If there are still outstanding DATA chunks left, the SHUTDOWN 2532 * receiver shall continue to follow normal data transmission 2533 * procedures defined in Section 6 until all outstanding DATA chunks 2534 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2535 * new data from its SCTP user. 2536 * 2537 * Verification Tag: 8.5 Verification Tag [Normal verification] 2538 * 2539 * Inputs 2540 * (endpoint, asoc, chunk) 2541 * 2542 * Outputs 2543 * (asoc, reply_msg, msg_up, timers, counters) 2544 * 2545 * The return value is the disposition of the chunk. 2546 */ 2547 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2548 const struct sctp_association *asoc, 2549 const sctp_subtype_t type, 2550 void *arg, 2551 sctp_cmd_seq_t *commands) 2552 { 2553 struct sctp_chunk *chunk = arg; 2554 sctp_shutdownhdr_t *sdh; 2555 sctp_disposition_t disposition; 2556 struct sctp_ulpevent *ev; 2557 2558 if (!sctp_vtag_verify(chunk, asoc)) 2559 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2560 2561 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2562 if (!sctp_chunk_length_valid(chunk, 2563 sizeof(struct sctp_shutdown_chunk_t))) 2564 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2565 commands); 2566 2567 /* Convert the elaborate header. */ 2568 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2569 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2570 chunk->subh.shutdown_hdr = sdh; 2571 2572 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2573 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2574 * inform the application that it should cease sending data. 2575 */ 2576 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2577 if (!ev) { 2578 disposition = SCTP_DISPOSITION_NOMEM; 2579 goto out; 2580 } 2581 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2582 2583 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2584 * - enter the SHUTDOWN-RECEIVED state, 2585 * - stop accepting new data from its SCTP user 2586 * 2587 * [This is implicit in the new state.] 2588 */ 2589 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2590 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2591 disposition = SCTP_DISPOSITION_CONSUME; 2592 2593 if (sctp_outq_is_empty(&asoc->outqueue)) { 2594 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2595 arg, commands); 2596 } 2597 2598 if (SCTP_DISPOSITION_NOMEM == disposition) 2599 goto out; 2600 2601 /* - verify, by checking the Cumulative TSN Ack field of the 2602 * chunk, that all its outstanding DATA chunks have been 2603 * received by the SHUTDOWN sender. 2604 */ 2605 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2606 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2607 2608 out: 2609 return disposition; 2610 } 2611 2612 /* RFC 2960 9.2 2613 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2614 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2615 * transport addresses (either in the IP addresses or in the INIT chunk) 2616 * that belong to this association, it should discard the INIT chunk and 2617 * retransmit the SHUTDOWN ACK chunk. 2618 */ 2619 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2620 const struct sctp_association *asoc, 2621 const sctp_subtype_t type, 2622 void *arg, 2623 sctp_cmd_seq_t *commands) 2624 { 2625 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2626 struct sctp_chunk *reply; 2627 2628 /* Make sure that the chunk has a valid length */ 2629 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2630 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2631 commands); 2632 2633 /* Since we are not going to really process this INIT, there 2634 * is no point in verifying chunk boundries. Just generate 2635 * the SHUTDOWN ACK. 2636 */ 2637 reply = sctp_make_shutdown_ack(asoc, chunk); 2638 if (NULL == reply) 2639 goto nomem; 2640 2641 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2642 * the T2-SHUTDOWN timer. 2643 */ 2644 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2645 2646 /* and restart the T2-shutdown timer. */ 2647 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2648 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2649 2650 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2651 2652 return SCTP_DISPOSITION_CONSUME; 2653 nomem: 2654 return SCTP_DISPOSITION_NOMEM; 2655 } 2656 2657 /* 2658 * sctp_sf_do_ecn_cwr 2659 * 2660 * Section: Appendix A: Explicit Congestion Notification 2661 * 2662 * CWR: 2663 * 2664 * RFC 2481 details a specific bit for a sender to send in the header of 2665 * its next outbound TCP segment to indicate to its peer that it has 2666 * reduced its congestion window. This is termed the CWR bit. For 2667 * SCTP the same indication is made by including the CWR chunk. 2668 * This chunk contains one data element, i.e. the TSN number that 2669 * was sent in the ECNE chunk. This element represents the lowest 2670 * TSN number in the datagram that was originally marked with the 2671 * CE bit. 2672 * 2673 * Verification Tag: 8.5 Verification Tag [Normal verification] 2674 * Inputs 2675 * (endpoint, asoc, chunk) 2676 * 2677 * Outputs 2678 * (asoc, reply_msg, msg_up, timers, counters) 2679 * 2680 * The return value is the disposition of the chunk. 2681 */ 2682 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2683 const struct sctp_association *asoc, 2684 const sctp_subtype_t type, 2685 void *arg, 2686 sctp_cmd_seq_t *commands) 2687 { 2688 sctp_cwrhdr_t *cwr; 2689 struct sctp_chunk *chunk = arg; 2690 u32 lowest_tsn; 2691 2692 if (!sctp_vtag_verify(chunk, asoc)) 2693 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2694 2695 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2696 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2697 commands); 2698 2699 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2700 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2701 2702 lowest_tsn = ntohl(cwr->lowest_tsn); 2703 2704 /* Does this CWR ack the last sent congestion notification? */ 2705 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2706 /* Stop sending ECNE. */ 2707 sctp_add_cmd_sf(commands, 2708 SCTP_CMD_ECN_CWR, 2709 SCTP_U32(lowest_tsn)); 2710 } 2711 return SCTP_DISPOSITION_CONSUME; 2712 } 2713 2714 /* 2715 * sctp_sf_do_ecne 2716 * 2717 * Section: Appendix A: Explicit Congestion Notification 2718 * 2719 * ECN-Echo 2720 * 2721 * RFC 2481 details a specific bit for a receiver to send back in its 2722 * TCP acknowledgements to notify the sender of the Congestion 2723 * Experienced (CE) bit having arrived from the network. For SCTP this 2724 * same indication is made by including the ECNE chunk. This chunk 2725 * contains one data element, i.e. the lowest TSN associated with the IP 2726 * datagram marked with the CE bit..... 2727 * 2728 * Verification Tag: 8.5 Verification Tag [Normal verification] 2729 * Inputs 2730 * (endpoint, asoc, chunk) 2731 * 2732 * Outputs 2733 * (asoc, reply_msg, msg_up, timers, counters) 2734 * 2735 * The return value is the disposition of the chunk. 2736 */ 2737 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2738 const struct sctp_association *asoc, 2739 const sctp_subtype_t type, 2740 void *arg, 2741 sctp_cmd_seq_t *commands) 2742 { 2743 sctp_ecnehdr_t *ecne; 2744 struct sctp_chunk *chunk = arg; 2745 2746 if (!sctp_vtag_verify(chunk, asoc)) 2747 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2748 2749 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2750 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2751 commands); 2752 2753 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2754 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2755 2756 /* If this is a newer ECNE than the last CWR packet we sent out */ 2757 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2758 SCTP_U32(ntohl(ecne->lowest_tsn))); 2759 2760 return SCTP_DISPOSITION_CONSUME; 2761 } 2762 2763 /* 2764 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2765 * 2766 * The SCTP endpoint MUST always acknowledge the reception of each valid 2767 * DATA chunk. 2768 * 2769 * The guidelines on delayed acknowledgement algorithm specified in 2770 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2771 * acknowledgement SHOULD be generated for at least every second packet 2772 * (not every second DATA chunk) received, and SHOULD be generated within 2773 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2774 * situations it may be beneficial for an SCTP transmitter to be more 2775 * conservative than the algorithms detailed in this document allow. 2776 * However, an SCTP transmitter MUST NOT be more aggressive than the 2777 * following algorithms allow. 2778 * 2779 * A SCTP receiver MUST NOT generate more than one SACK for every 2780 * incoming packet, other than to update the offered window as the 2781 * receiving application consumes new data. 2782 * 2783 * Verification Tag: 8.5 Verification Tag [Normal verification] 2784 * 2785 * Inputs 2786 * (endpoint, asoc, chunk) 2787 * 2788 * Outputs 2789 * (asoc, reply_msg, msg_up, timers, counters) 2790 * 2791 * The return value is the disposition of the chunk. 2792 */ 2793 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2794 const struct sctp_association *asoc, 2795 const sctp_subtype_t type, 2796 void *arg, 2797 sctp_cmd_seq_t *commands) 2798 { 2799 struct sctp_chunk *chunk = arg; 2800 int error; 2801 2802 if (!sctp_vtag_verify(chunk, asoc)) { 2803 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2804 SCTP_NULL()); 2805 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2806 } 2807 2808 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2809 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2810 commands); 2811 2812 error = sctp_eat_data(asoc, chunk, commands ); 2813 switch (error) { 2814 case SCTP_IERROR_NO_ERROR: 2815 break; 2816 case SCTP_IERROR_HIGH_TSN: 2817 case SCTP_IERROR_BAD_STREAM: 2818 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2819 goto discard_noforce; 2820 case SCTP_IERROR_DUP_TSN: 2821 case SCTP_IERROR_IGNORE_TSN: 2822 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2823 goto discard_force; 2824 case SCTP_IERROR_NO_DATA: 2825 goto consume; 2826 default: 2827 BUG(); 2828 } 2829 2830 if (asoc->autoclose) { 2831 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2832 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2833 } 2834 2835 /* If this is the last chunk in a packet, we need to count it 2836 * toward sack generation. Note that we need to SACK every 2837 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2838 * THEM. We elect to NOT generate SACK's if the chunk fails 2839 * the verification tag test. 2840 * 2841 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2842 * 2843 * The SCTP endpoint MUST always acknowledge the reception of 2844 * each valid DATA chunk. 2845 * 2846 * The guidelines on delayed acknowledgement algorithm 2847 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2848 * Specifically, an acknowledgement SHOULD be generated for at 2849 * least every second packet (not every second DATA chunk) 2850 * received, and SHOULD be generated within 200 ms of the 2851 * arrival of any unacknowledged DATA chunk. In some 2852 * situations it may be beneficial for an SCTP transmitter to 2853 * be more conservative than the algorithms detailed in this 2854 * document allow. However, an SCTP transmitter MUST NOT be 2855 * more aggressive than the following algorithms allow. 2856 */ 2857 if (chunk->end_of_packet) 2858 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2859 2860 return SCTP_DISPOSITION_CONSUME; 2861 2862 discard_force: 2863 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2864 * 2865 * When a packet arrives with duplicate DATA chunk(s) and with 2866 * no new DATA chunk(s), the endpoint MUST immediately send a 2867 * SACK with no delay. If a packet arrives with duplicate 2868 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2869 * MAY immediately send a SACK. Normally receipt of duplicate 2870 * DATA chunks will occur when the original SACK chunk was lost 2871 * and the peer's RTO has expired. The duplicate TSN number(s) 2872 * SHOULD be reported in the SACK as duplicate. 2873 */ 2874 /* In our case, we split the MAY SACK advice up whether or not 2875 * the last chunk is a duplicate.' 2876 */ 2877 if (chunk->end_of_packet) 2878 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2879 return SCTP_DISPOSITION_DISCARD; 2880 2881 discard_noforce: 2882 if (chunk->end_of_packet) 2883 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2884 2885 return SCTP_DISPOSITION_DISCARD; 2886 consume: 2887 return SCTP_DISPOSITION_CONSUME; 2888 2889 } 2890 2891 /* 2892 * sctp_sf_eat_data_fast_4_4 2893 * 2894 * Section: 4 (4) 2895 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2896 * DATA chunks without delay. 2897 * 2898 * Verification Tag: 8.5 Verification Tag [Normal verification] 2899 * Inputs 2900 * (endpoint, asoc, chunk) 2901 * 2902 * Outputs 2903 * (asoc, reply_msg, msg_up, timers, counters) 2904 * 2905 * The return value is the disposition of the chunk. 2906 */ 2907 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2908 const struct sctp_association *asoc, 2909 const sctp_subtype_t type, 2910 void *arg, 2911 sctp_cmd_seq_t *commands) 2912 { 2913 struct sctp_chunk *chunk = arg; 2914 int error; 2915 2916 if (!sctp_vtag_verify(chunk, asoc)) { 2917 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2918 SCTP_NULL()); 2919 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2920 } 2921 2922 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2923 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2924 commands); 2925 2926 error = sctp_eat_data(asoc, chunk, commands ); 2927 switch (error) { 2928 case SCTP_IERROR_NO_ERROR: 2929 case SCTP_IERROR_HIGH_TSN: 2930 case SCTP_IERROR_DUP_TSN: 2931 case SCTP_IERROR_IGNORE_TSN: 2932 case SCTP_IERROR_BAD_STREAM: 2933 break; 2934 case SCTP_IERROR_NO_DATA: 2935 goto consume; 2936 default: 2937 BUG(); 2938 } 2939 2940 /* Go a head and force a SACK, since we are shutting down. */ 2941 2942 /* Implementor's Guide. 2943 * 2944 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 2945 * respond to each received packet containing one or more DATA chunk(s) 2946 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 2947 */ 2948 if (chunk->end_of_packet) { 2949 /* We must delay the chunk creation since the cumulative 2950 * TSN has not been updated yet. 2951 */ 2952 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 2953 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2954 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2955 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2956 } 2957 2958 consume: 2959 return SCTP_DISPOSITION_CONSUME; 2960 } 2961 2962 /* 2963 * Section: 6.2 Processing a Received SACK 2964 * D) Any time a SACK arrives, the endpoint performs the following: 2965 * 2966 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 2967 * then drop the SACK. Since Cumulative TSN Ack is monotonically 2968 * increasing, a SACK whose Cumulative TSN Ack is less than the 2969 * Cumulative TSN Ack Point indicates an out-of-order SACK. 2970 * 2971 * ii) Set rwnd equal to the newly received a_rwnd minus the number 2972 * of bytes still outstanding after processing the Cumulative TSN Ack 2973 * and the Gap Ack Blocks. 2974 * 2975 * iii) If the SACK is missing a TSN that was previously 2976 * acknowledged via a Gap Ack Block (e.g., the data receiver 2977 * reneged on the data), then mark the corresponding DATA chunk 2978 * as available for retransmit: Mark it as missing for fast 2979 * retransmit as described in Section 7.2.4 and if no retransmit 2980 * timer is running for the destination address to which the DATA 2981 * chunk was originally transmitted, then T3-rtx is started for 2982 * that destination address. 2983 * 2984 * Verification Tag: 8.5 Verification Tag [Normal verification] 2985 * 2986 * Inputs 2987 * (endpoint, asoc, chunk) 2988 * 2989 * Outputs 2990 * (asoc, reply_msg, msg_up, timers, counters) 2991 * 2992 * The return value is the disposition of the chunk. 2993 */ 2994 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 2995 const struct sctp_association *asoc, 2996 const sctp_subtype_t type, 2997 void *arg, 2998 sctp_cmd_seq_t *commands) 2999 { 3000 struct sctp_chunk *chunk = arg; 3001 sctp_sackhdr_t *sackh; 3002 __u32 ctsn; 3003 3004 if (!sctp_vtag_verify(chunk, asoc)) 3005 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3006 3007 /* Make sure that the SACK chunk has a valid length. */ 3008 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3009 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3010 commands); 3011 3012 /* Pull the SACK chunk from the data buffer */ 3013 sackh = sctp_sm_pull_sack(chunk); 3014 /* Was this a bogus SACK? */ 3015 if (!sackh) 3016 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3017 chunk->subh.sack_hdr = sackh; 3018 ctsn = ntohl(sackh->cum_tsn_ack); 3019 3020 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3021 * Ack Point, then drop the SACK. Since Cumulative TSN 3022 * Ack is monotonically increasing, a SACK whose 3023 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3024 * Point indicates an out-of-order SACK. 3025 */ 3026 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3027 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3028 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3029 return SCTP_DISPOSITION_DISCARD; 3030 } 3031 3032 /* If Cumulative TSN Ack beyond the max tsn currently 3033 * send, terminating the association and respond to the 3034 * sender with an ABORT. 3035 */ 3036 if (!TSN_lt(ctsn, asoc->next_tsn)) 3037 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 3038 3039 /* Return this SACK for further processing. */ 3040 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 3041 3042 /* Note: We do the rest of the work on the PROCESS_SACK 3043 * sideeffect. 3044 */ 3045 return SCTP_DISPOSITION_CONSUME; 3046 } 3047 3048 /* 3049 * Generate an ABORT in response to a packet. 3050 * 3051 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3052 * 3053 * 8) The receiver should respond to the sender of the OOTB packet with 3054 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3055 * MUST fill in the Verification Tag field of the outbound packet 3056 * with the value found in the Verification Tag field of the OOTB 3057 * packet and set the T-bit in the Chunk Flags to indicate that the 3058 * Verification Tag is reflected. After sending this ABORT, the 3059 * receiver of the OOTB packet shall discard the OOTB packet and take 3060 * no further action. 3061 * 3062 * Verification Tag: 3063 * 3064 * The return value is the disposition of the chunk. 3065 */ 3066 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 3067 const struct sctp_association *asoc, 3068 const sctp_subtype_t type, 3069 void *arg, 3070 sctp_cmd_seq_t *commands) 3071 { 3072 struct sctp_packet *packet = NULL; 3073 struct sctp_chunk *chunk = arg; 3074 struct sctp_chunk *abort; 3075 3076 packet = sctp_ootb_pkt_new(asoc, chunk); 3077 3078 if (packet) { 3079 /* Make an ABORT. The T bit will be set if the asoc 3080 * is NULL. 3081 */ 3082 abort = sctp_make_abort(asoc, chunk, 0); 3083 if (!abort) { 3084 sctp_ootb_pkt_free(packet); 3085 return SCTP_DISPOSITION_NOMEM; 3086 } 3087 3088 /* Reflect vtag if T-Bit is set */ 3089 if (sctp_test_T_bit(abort)) 3090 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3091 3092 /* Set the skb to the belonging sock for accounting. */ 3093 abort->skb->sk = ep->base.sk; 3094 3095 sctp_packet_append_chunk(packet, abort); 3096 3097 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3098 SCTP_PACKET(packet)); 3099 3100 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3101 3102 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3103 return SCTP_DISPOSITION_CONSUME; 3104 } 3105 3106 return SCTP_DISPOSITION_NOMEM; 3107 } 3108 3109 /* 3110 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3111 * event as ULP notification for each cause included in the chunk. 3112 * 3113 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3114 * 3115 * The return value is the disposition of the chunk. 3116 */ 3117 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 3118 const struct sctp_association *asoc, 3119 const sctp_subtype_t type, 3120 void *arg, 3121 sctp_cmd_seq_t *commands) 3122 { 3123 struct sctp_chunk *chunk = arg; 3124 struct sctp_ulpevent *ev; 3125 3126 if (!sctp_vtag_verify(chunk, asoc)) 3127 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3128 3129 /* Make sure that the ERROR chunk has a valid length. */ 3130 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3131 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3132 commands); 3133 3134 while (chunk->chunk_end > chunk->skb->data) { 3135 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 3136 GFP_ATOMIC); 3137 if (!ev) 3138 goto nomem; 3139 3140 if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP, 3141 SCTP_ULPEVENT(ev))) { 3142 sctp_ulpevent_free(ev); 3143 goto nomem; 3144 } 3145 3146 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3147 SCTP_CHUNK(chunk)); 3148 } 3149 return SCTP_DISPOSITION_CONSUME; 3150 3151 nomem: 3152 return SCTP_DISPOSITION_NOMEM; 3153 } 3154 3155 /* 3156 * Process an inbound SHUTDOWN ACK. 3157 * 3158 * From Section 9.2: 3159 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3160 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3161 * peer, and remove all record of the association. 3162 * 3163 * The return value is the disposition. 3164 */ 3165 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3166 const struct sctp_association *asoc, 3167 const sctp_subtype_t type, 3168 void *arg, 3169 sctp_cmd_seq_t *commands) 3170 { 3171 struct sctp_chunk *chunk = arg; 3172 struct sctp_chunk *reply; 3173 struct sctp_ulpevent *ev; 3174 3175 if (!sctp_vtag_verify(chunk, asoc)) 3176 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3177 3178 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3179 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3180 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3181 commands); 3182 /* 10.2 H) SHUTDOWN COMPLETE notification 3183 * 3184 * When SCTP completes the shutdown procedures (section 9.2) this 3185 * notification is passed to the upper layer. 3186 */ 3187 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3188 0, 0, 0, NULL, GFP_ATOMIC); 3189 if (!ev) 3190 goto nomem; 3191 3192 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3193 reply = sctp_make_shutdown_complete(asoc, chunk); 3194 if (!reply) 3195 goto nomem_chunk; 3196 3197 /* Do all the commands now (after allocation), so that we 3198 * have consistent state if memory allocation failes 3199 */ 3200 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3201 3202 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3203 * stop the T2-shutdown timer, 3204 */ 3205 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3206 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3207 3208 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3209 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3210 3211 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3212 SCTP_STATE(SCTP_STATE_CLOSED)); 3213 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3214 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3215 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3216 3217 /* ...and remove all record of the association. */ 3218 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3219 return SCTP_DISPOSITION_DELETE_TCB; 3220 3221 nomem_chunk: 3222 sctp_ulpevent_free(ev); 3223 nomem: 3224 return SCTP_DISPOSITION_NOMEM; 3225 } 3226 3227 /* 3228 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3229 * 3230 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3231 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3232 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3233 * packet must fill in the Verification Tag field of the outbound 3234 * packet with the Verification Tag received in the SHUTDOWN ACK and 3235 * set the T-bit in the Chunk Flags to indicate that the Verification 3236 * Tag is reflected. 3237 * 3238 * 8) The receiver should respond to the sender of the OOTB packet with 3239 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3240 * MUST fill in the Verification Tag field of the outbound packet 3241 * with the value found in the Verification Tag field of the OOTB 3242 * packet and set the T-bit in the Chunk Flags to indicate that the 3243 * Verification Tag is reflected. After sending this ABORT, the 3244 * receiver of the OOTB packet shall discard the OOTB packet and take 3245 * no further action. 3246 */ 3247 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3248 const struct sctp_association *asoc, 3249 const sctp_subtype_t type, 3250 void *arg, 3251 sctp_cmd_seq_t *commands) 3252 { 3253 struct sctp_chunk *chunk = arg; 3254 struct sk_buff *skb = chunk->skb; 3255 sctp_chunkhdr_t *ch; 3256 __u8 *ch_end; 3257 int ootb_shut_ack = 0; 3258 3259 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3260 3261 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3262 do { 3263 /* Report violation if the chunk is less then minimal */ 3264 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3265 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3266 commands); 3267 3268 /* Now that we know we at least have a chunk header, 3269 * do things that are type appropriate. 3270 */ 3271 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3272 ootb_shut_ack = 1; 3273 3274 /* RFC 2960, Section 3.3.7 3275 * Moreover, under any circumstances, an endpoint that 3276 * receives an ABORT MUST NOT respond to that ABORT by 3277 * sending an ABORT of its own. 3278 */ 3279 if (SCTP_CID_ABORT == ch->type) 3280 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3281 3282 /* Report violation if chunk len overflows */ 3283 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3284 if (ch_end > skb_tail_pointer(skb)) 3285 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3286 commands); 3287 3288 ch = (sctp_chunkhdr_t *) ch_end; 3289 } while (ch_end < skb_tail_pointer(skb)); 3290 3291 if (ootb_shut_ack) 3292 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3293 else 3294 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3295 } 3296 3297 /* 3298 * Handle an "Out of the blue" SHUTDOWN ACK. 3299 * 3300 * Section: 8.4 5, sctpimpguide 2.41. 3301 * 3302 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3303 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3304 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3305 * packet must fill in the Verification Tag field of the outbound 3306 * packet with the Verification Tag received in the SHUTDOWN ACK and 3307 * set the T-bit in the Chunk Flags to indicate that the Verification 3308 * Tag is reflected. 3309 * 3310 * Inputs 3311 * (endpoint, asoc, type, arg, commands) 3312 * 3313 * Outputs 3314 * (sctp_disposition_t) 3315 * 3316 * The return value is the disposition of the chunk. 3317 */ 3318 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3319 const struct sctp_association *asoc, 3320 const sctp_subtype_t type, 3321 void *arg, 3322 sctp_cmd_seq_t *commands) 3323 { 3324 struct sctp_packet *packet = NULL; 3325 struct sctp_chunk *chunk = arg; 3326 struct sctp_chunk *shut; 3327 3328 packet = sctp_ootb_pkt_new(asoc, chunk); 3329 3330 if (packet) { 3331 /* Make an SHUTDOWN_COMPLETE. 3332 * The T bit will be set if the asoc is NULL. 3333 */ 3334 shut = sctp_make_shutdown_complete(asoc, chunk); 3335 if (!shut) { 3336 sctp_ootb_pkt_free(packet); 3337 return SCTP_DISPOSITION_NOMEM; 3338 } 3339 3340 /* Reflect vtag if T-Bit is set */ 3341 if (sctp_test_T_bit(shut)) 3342 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3343 3344 /* Set the skb to the belonging sock for accounting. */ 3345 shut->skb->sk = ep->base.sk; 3346 3347 sctp_packet_append_chunk(packet, shut); 3348 3349 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3350 SCTP_PACKET(packet)); 3351 3352 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3353 3354 /* If the chunk length is invalid, we don't want to process 3355 * the reset of the packet. 3356 */ 3357 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3358 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3359 3360 /* We need to discard the rest of the packet to prevent 3361 * potential bomming attacks from additional bundled chunks. 3362 * This is documented in SCTP Threats ID. 3363 */ 3364 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3365 } 3366 3367 return SCTP_DISPOSITION_NOMEM; 3368 } 3369 3370 /* 3371 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3372 * 3373 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3374 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3375 * procedures in section 8.4 SHOULD be followed, in other words it 3376 * should be treated as an Out Of The Blue packet. 3377 * [This means that we do NOT check the Verification Tag on these 3378 * chunks. --piggy ] 3379 * 3380 */ 3381 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3382 const struct sctp_association *asoc, 3383 const sctp_subtype_t type, 3384 void *arg, 3385 sctp_cmd_seq_t *commands) 3386 { 3387 struct sctp_chunk *chunk = arg; 3388 3389 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3390 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3391 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3392 commands); 3393 3394 /* Although we do have an association in this case, it corresponds 3395 * to a restarted association. So the packet is treated as an OOTB 3396 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3397 * called with a NULL association. 3398 */ 3399 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3400 } 3401 3402 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3403 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3404 const struct sctp_association *asoc, 3405 const sctp_subtype_t type, void *arg, 3406 sctp_cmd_seq_t *commands) 3407 { 3408 struct sctp_chunk *chunk = arg; 3409 struct sctp_chunk *asconf_ack = NULL; 3410 struct sctp_paramhdr *err_param = NULL; 3411 sctp_addiphdr_t *hdr; 3412 union sctp_addr_param *addr_param; 3413 __u32 serial; 3414 int length; 3415 3416 if (!sctp_vtag_verify(chunk, asoc)) { 3417 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3418 SCTP_NULL()); 3419 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3420 } 3421 3422 /* ADD-IP: Section 4.1.1 3423 * This chunk MUST be sent in an authenticated way by using 3424 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3425 * is received unauthenticated it MUST be silently discarded as 3426 * described in [I-D.ietf-tsvwg-sctp-auth]. 3427 */ 3428 if (!sctp_addip_noauth && !chunk->auth) 3429 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3430 3431 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3432 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3433 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3434 commands); 3435 3436 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3437 serial = ntohl(hdr->serial); 3438 3439 addr_param = (union sctp_addr_param *)hdr->params; 3440 length = ntohs(addr_param->p.length); 3441 if (length < sizeof(sctp_paramhdr_t)) 3442 return sctp_sf_violation_paramlen(ep, asoc, type, 3443 (void *)addr_param, commands); 3444 3445 /* Verify the ASCONF chunk before processing it. */ 3446 if (!sctp_verify_asconf(asoc, 3447 (sctp_paramhdr_t *)((void *)addr_param + length), 3448 (void *)chunk->chunk_end, 3449 &err_param)) 3450 return sctp_sf_violation_paramlen(ep, asoc, type, 3451 (void *)&err_param, commands); 3452 3453 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3454 * the endpoint stored in a new association variable 3455 * 'Peer-Serial-Number'. 3456 */ 3457 if (serial == asoc->peer.addip_serial + 1) { 3458 /* If this is the first instance of ASCONF in the packet, 3459 * we can clean our old ASCONF-ACKs. 3460 */ 3461 if (!chunk->has_asconf) 3462 sctp_assoc_clean_asconf_ack_cache(asoc); 3463 3464 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3465 * expected, process the ASCONF as described below and after 3466 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3467 * the response packet and cache a copy of it (in the event it 3468 * later needs to be retransmitted). 3469 * 3470 * Essentially, do V1-V5. 3471 */ 3472 asconf_ack = sctp_process_asconf((struct sctp_association *) 3473 asoc, chunk); 3474 if (!asconf_ack) 3475 return SCTP_DISPOSITION_NOMEM; 3476 } else if (serial < asoc->peer.addip_serial + 1) { 3477 /* ADDIP 5.2 E2) 3478 * If the value found in the Sequence Number is less than the 3479 * ('Peer- Sequence-Number' + 1), simply skip to the next 3480 * ASCONF, and include in the outbound response packet 3481 * any previously cached ASCONF-ACK response that was 3482 * sent and saved that matches the Sequence Number of the 3483 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3484 * Chunk exists. This will occur when an older ASCONF 3485 * arrives out of order. In such a case, the receiver 3486 * should skip the ASCONF Chunk and not include ASCONF-ACK 3487 * Chunk for that chunk. 3488 */ 3489 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3490 if (!asconf_ack) 3491 return SCTP_DISPOSITION_DISCARD; 3492 } else { 3493 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3494 * it must be either a stale packet or from an attacker. 3495 */ 3496 return SCTP_DISPOSITION_DISCARD; 3497 } 3498 3499 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3500 * containing the ASCONF-ACK Chunks MUST be the source address of 3501 * the SCTP packet that held the ASCONF Chunks. 3502 * 3503 * To do this properly, we'll set the destination address of the chunk 3504 * and at the transmit time, will try look up the transport to use. 3505 * Since ASCONFs may be bundled, the correct transport may not be 3506 * created untill we process the entire packet, thus this workaround. 3507 */ 3508 asconf_ack->dest = chunk->source; 3509 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3510 3511 return SCTP_DISPOSITION_CONSUME; 3512 } 3513 3514 /* 3515 * ADDIP Section 4.3 General rules for address manipulation 3516 * When building TLV parameters for the ASCONF Chunk that will add or 3517 * delete IP addresses the D0 to D13 rules should be applied: 3518 */ 3519 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3520 const struct sctp_association *asoc, 3521 const sctp_subtype_t type, void *arg, 3522 sctp_cmd_seq_t *commands) 3523 { 3524 struct sctp_chunk *asconf_ack = arg; 3525 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3526 struct sctp_chunk *abort; 3527 struct sctp_paramhdr *err_param = NULL; 3528 sctp_addiphdr_t *addip_hdr; 3529 __u32 sent_serial, rcvd_serial; 3530 3531 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3532 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3533 SCTP_NULL()); 3534 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3535 } 3536 3537 /* ADD-IP, Section 4.1.2: 3538 * This chunk MUST be sent in an authenticated way by using 3539 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3540 * is received unauthenticated it MUST be silently discarded as 3541 * described in [I-D.ietf-tsvwg-sctp-auth]. 3542 */ 3543 if (!sctp_addip_noauth && !asconf_ack->auth) 3544 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3545 3546 /* Make sure that the ADDIP chunk has a valid length. */ 3547 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3548 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3549 commands); 3550 3551 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3552 rcvd_serial = ntohl(addip_hdr->serial); 3553 3554 /* Verify the ASCONF-ACK chunk before processing it. */ 3555 if (!sctp_verify_asconf(asoc, 3556 (sctp_paramhdr_t *)addip_hdr->params, 3557 (void *)asconf_ack->chunk_end, 3558 &err_param)) 3559 return sctp_sf_violation_paramlen(ep, asoc, type, 3560 (void *)&err_param, commands); 3561 3562 if (last_asconf) { 3563 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3564 sent_serial = ntohl(addip_hdr->serial); 3565 } else { 3566 sent_serial = asoc->addip_serial - 1; 3567 } 3568 3569 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3570 * equal to the next serial number to be used but no ASCONF chunk is 3571 * outstanding the endpoint MUST ABORT the association. Note that a 3572 * sequence number is greater than if it is no more than 2^^31-1 3573 * larger than the current sequence number (using serial arithmetic). 3574 */ 3575 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3576 !(asoc->addip_last_asconf)) { 3577 abort = sctp_make_abort(asoc, asconf_ack, 3578 sizeof(sctp_errhdr_t)); 3579 if (abort) { 3580 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3581 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3582 SCTP_CHUNK(abort)); 3583 } 3584 /* We are going to ABORT, so we might as well stop 3585 * processing the rest of the chunks in the packet. 3586 */ 3587 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3588 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3589 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3590 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3591 SCTP_ERROR(ECONNABORTED)); 3592 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3593 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3594 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3595 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3596 return SCTP_DISPOSITION_ABORT; 3597 } 3598 3599 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3600 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3601 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3602 3603 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3604 asconf_ack)) 3605 return SCTP_DISPOSITION_CONSUME; 3606 3607 abort = sctp_make_abort(asoc, asconf_ack, 3608 sizeof(sctp_errhdr_t)); 3609 if (abort) { 3610 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3611 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3612 SCTP_CHUNK(abort)); 3613 } 3614 /* We are going to ABORT, so we might as well stop 3615 * processing the rest of the chunks in the packet. 3616 */ 3617 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3618 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3619 SCTP_ERROR(ECONNABORTED)); 3620 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3621 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3622 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3623 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3624 return SCTP_DISPOSITION_ABORT; 3625 } 3626 3627 return SCTP_DISPOSITION_DISCARD; 3628 } 3629 3630 /* 3631 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3632 * 3633 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3634 * its cumulative TSN point to the value carried in the FORWARD TSN 3635 * chunk, and then MUST further advance its cumulative TSN point locally 3636 * if possible. 3637 * After the above processing, the data receiver MUST stop reporting any 3638 * missing TSNs earlier than or equal to the new cumulative TSN point. 3639 * 3640 * Verification Tag: 8.5 Verification Tag [Normal verification] 3641 * 3642 * The return value is the disposition of the chunk. 3643 */ 3644 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3645 const struct sctp_association *asoc, 3646 const sctp_subtype_t type, 3647 void *arg, 3648 sctp_cmd_seq_t *commands) 3649 { 3650 struct sctp_chunk *chunk = arg; 3651 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3652 __u16 len; 3653 __u32 tsn; 3654 3655 if (!sctp_vtag_verify(chunk, asoc)) { 3656 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3657 SCTP_NULL()); 3658 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3659 } 3660 3661 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3662 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3663 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3664 commands); 3665 3666 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3667 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3668 len = ntohs(chunk->chunk_hdr->length); 3669 len -= sizeof(struct sctp_chunkhdr); 3670 skb_pull(chunk->skb, len); 3671 3672 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3673 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3674 3675 /* The TSN is too high--silently discard the chunk and count on it 3676 * getting retransmitted later. 3677 */ 3678 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3679 goto discard_noforce; 3680 3681 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3682 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3683 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3684 SCTP_CHUNK(chunk)); 3685 3686 /* Count this as receiving DATA. */ 3687 if (asoc->autoclose) { 3688 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3689 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3690 } 3691 3692 /* FIXME: For now send a SACK, but DATA processing may 3693 * send another. 3694 */ 3695 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3696 3697 return SCTP_DISPOSITION_CONSUME; 3698 3699 discard_noforce: 3700 return SCTP_DISPOSITION_DISCARD; 3701 } 3702 3703 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3704 const struct sctp_endpoint *ep, 3705 const struct sctp_association *asoc, 3706 const sctp_subtype_t type, 3707 void *arg, 3708 sctp_cmd_seq_t *commands) 3709 { 3710 struct sctp_chunk *chunk = arg; 3711 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3712 __u16 len; 3713 __u32 tsn; 3714 3715 if (!sctp_vtag_verify(chunk, asoc)) { 3716 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3717 SCTP_NULL()); 3718 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3719 } 3720 3721 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3722 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3723 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3724 commands); 3725 3726 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3727 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3728 len = ntohs(chunk->chunk_hdr->length); 3729 len -= sizeof(struct sctp_chunkhdr); 3730 skb_pull(chunk->skb, len); 3731 3732 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3733 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3734 3735 /* The TSN is too high--silently discard the chunk and count on it 3736 * getting retransmitted later. 3737 */ 3738 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3739 goto gen_shutdown; 3740 3741 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3742 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3743 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3744 SCTP_CHUNK(chunk)); 3745 3746 /* Go a head and force a SACK, since we are shutting down. */ 3747 gen_shutdown: 3748 /* Implementor's Guide. 3749 * 3750 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3751 * respond to each received packet containing one or more DATA chunk(s) 3752 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3753 */ 3754 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3755 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3756 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3757 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3758 3759 return SCTP_DISPOSITION_CONSUME; 3760 } 3761 3762 /* 3763 * SCTP-AUTH Section 6.3 Receving authenticated chukns 3764 * 3765 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3766 * Identifier field. If this algorithm was not specified by the 3767 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3768 * during association setup, the AUTH chunk and all chunks after it MUST 3769 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3770 * defined in Section 4.1. 3771 * 3772 * If an endpoint with no shared key receives a Shared Key Identifier 3773 * other than 0, it MUST silently discard all authenticated chunks. If 3774 * the endpoint has at least one endpoint pair shared key for the peer, 3775 * it MUST use the key specified by the Shared Key Identifier if a 3776 * key has been configured for that Shared Key Identifier. If no 3777 * endpoint pair shared key has been configured for that Shared Key 3778 * Identifier, all authenticated chunks MUST be silently discarded. 3779 * 3780 * Verification Tag: 8.5 Verification Tag [Normal verification] 3781 * 3782 * The return value is the disposition of the chunk. 3783 */ 3784 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 3785 const struct sctp_association *asoc, 3786 const sctp_subtype_t type, 3787 struct sctp_chunk *chunk) 3788 { 3789 struct sctp_authhdr *auth_hdr; 3790 struct sctp_hmac *hmac; 3791 unsigned int sig_len; 3792 __u16 key_id; 3793 __u8 *save_digest; 3794 __u8 *digest; 3795 3796 /* Pull in the auth header, so we can do some more verification */ 3797 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3798 chunk->subh.auth_hdr = auth_hdr; 3799 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3800 3801 /* Make sure that we suport the HMAC algorithm from the auth 3802 * chunk. 3803 */ 3804 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 3805 return SCTP_IERROR_AUTH_BAD_HMAC; 3806 3807 /* Make sure that the provided shared key identifier has been 3808 * configured 3809 */ 3810 key_id = ntohs(auth_hdr->shkey_id); 3811 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 3812 return SCTP_IERROR_AUTH_BAD_KEYID; 3813 3814 3815 /* Make sure that the length of the signature matches what 3816 * we expect. 3817 */ 3818 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 3819 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 3820 if (sig_len != hmac->hmac_len) 3821 return SCTP_IERROR_PROTO_VIOLATION; 3822 3823 /* Now that we've done validation checks, we can compute and 3824 * verify the hmac. The steps involved are: 3825 * 1. Save the digest from the chunk. 3826 * 2. Zero out the digest in the chunk. 3827 * 3. Compute the new digest 3828 * 4. Compare saved and new digests. 3829 */ 3830 digest = auth_hdr->hmac; 3831 skb_pull(chunk->skb, sig_len); 3832 3833 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 3834 if (!save_digest) 3835 goto nomem; 3836 3837 memset(digest, 0, sig_len); 3838 3839 sctp_auth_calculate_hmac(asoc, chunk->skb, 3840 (struct sctp_auth_chunk *)chunk->chunk_hdr, 3841 GFP_ATOMIC); 3842 3843 /* Discard the packet if the digests do not match */ 3844 if (memcmp(save_digest, digest, sig_len)) { 3845 kfree(save_digest); 3846 return SCTP_IERROR_BAD_SIG; 3847 } 3848 3849 kfree(save_digest); 3850 chunk->auth = 1; 3851 3852 return SCTP_IERROR_NO_ERROR; 3853 nomem: 3854 return SCTP_IERROR_NOMEM; 3855 } 3856 3857 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep, 3858 const struct sctp_association *asoc, 3859 const sctp_subtype_t type, 3860 void *arg, 3861 sctp_cmd_seq_t *commands) 3862 { 3863 struct sctp_authhdr *auth_hdr; 3864 struct sctp_chunk *chunk = arg; 3865 struct sctp_chunk *err_chunk; 3866 sctp_ierror_t error; 3867 3868 if (!sctp_vtag_verify(chunk, asoc)) { 3869 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3870 SCTP_NULL()); 3871 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3872 } 3873 3874 /* Make sure that the AUTH chunk has valid length. */ 3875 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 3876 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3877 commands); 3878 3879 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3880 error = sctp_sf_authenticate(ep, asoc, type, chunk); 3881 switch (error) { 3882 case SCTP_IERROR_AUTH_BAD_HMAC: 3883 /* Generate the ERROR chunk and discard the rest 3884 * of the packet 3885 */ 3886 err_chunk = sctp_make_op_error(asoc, chunk, 3887 SCTP_ERROR_UNSUP_HMAC, 3888 &auth_hdr->hmac_id, 3889 sizeof(__u16)); 3890 if (err_chunk) { 3891 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3892 SCTP_CHUNK(err_chunk)); 3893 } 3894 /* Fall Through */ 3895 case SCTP_IERROR_AUTH_BAD_KEYID: 3896 case SCTP_IERROR_BAD_SIG: 3897 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3898 break; 3899 case SCTP_IERROR_PROTO_VIOLATION: 3900 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3901 commands); 3902 break; 3903 case SCTP_IERROR_NOMEM: 3904 return SCTP_DISPOSITION_NOMEM; 3905 default: 3906 break; 3907 } 3908 3909 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 3910 struct sctp_ulpevent *ev; 3911 3912 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 3913 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 3914 3915 if (!ev) 3916 return -ENOMEM; 3917 3918 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3919 SCTP_ULPEVENT(ev)); 3920 } 3921 3922 return SCTP_DISPOSITION_CONSUME; 3923 } 3924 3925 /* 3926 * Process an unknown chunk. 3927 * 3928 * Section: 3.2. Also, 2.1 in the implementor's guide. 3929 * 3930 * Chunk Types are encoded such that the highest-order two bits specify 3931 * the action that must be taken if the processing endpoint does not 3932 * recognize the Chunk Type. 3933 * 3934 * 00 - Stop processing this SCTP packet and discard it, do not process 3935 * any further chunks within it. 3936 * 3937 * 01 - Stop processing this SCTP packet and discard it, do not process 3938 * any further chunks within it, and report the unrecognized 3939 * chunk in an 'Unrecognized Chunk Type'. 3940 * 3941 * 10 - Skip this chunk and continue processing. 3942 * 3943 * 11 - Skip this chunk and continue processing, but report in an ERROR 3944 * Chunk using the 'Unrecognized Chunk Type' cause of error. 3945 * 3946 * The return value is the disposition of the chunk. 3947 */ 3948 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 3949 const struct sctp_association *asoc, 3950 const sctp_subtype_t type, 3951 void *arg, 3952 sctp_cmd_seq_t *commands) 3953 { 3954 struct sctp_chunk *unk_chunk = arg; 3955 struct sctp_chunk *err_chunk; 3956 sctp_chunkhdr_t *hdr; 3957 3958 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 3959 3960 if (!sctp_vtag_verify(unk_chunk, asoc)) 3961 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3962 3963 /* Make sure that the chunk has a valid length. 3964 * Since we don't know the chunk type, we use a general 3965 * chunkhdr structure to make a comparison. 3966 */ 3967 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 3968 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3969 commands); 3970 3971 switch (type.chunk & SCTP_CID_ACTION_MASK) { 3972 case SCTP_CID_ACTION_DISCARD: 3973 /* Discard the packet. */ 3974 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3975 break; 3976 case SCTP_CID_ACTION_DISCARD_ERR: 3977 /* Discard the packet. */ 3978 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3979 3980 /* Generate an ERROR chunk as response. */ 3981 hdr = unk_chunk->chunk_hdr; 3982 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3983 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3984 WORD_ROUND(ntohs(hdr->length))); 3985 if (err_chunk) { 3986 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3987 SCTP_CHUNK(err_chunk)); 3988 } 3989 return SCTP_DISPOSITION_CONSUME; 3990 break; 3991 case SCTP_CID_ACTION_SKIP: 3992 /* Skip the chunk. */ 3993 return SCTP_DISPOSITION_DISCARD; 3994 break; 3995 case SCTP_CID_ACTION_SKIP_ERR: 3996 /* Generate an ERROR chunk as response. */ 3997 hdr = unk_chunk->chunk_hdr; 3998 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3999 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4000 WORD_ROUND(ntohs(hdr->length))); 4001 if (err_chunk) { 4002 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4003 SCTP_CHUNK(err_chunk)); 4004 } 4005 /* Skip the chunk. */ 4006 return SCTP_DISPOSITION_CONSUME; 4007 break; 4008 default: 4009 break; 4010 } 4011 4012 return SCTP_DISPOSITION_DISCARD; 4013 } 4014 4015 /* 4016 * Discard the chunk. 4017 * 4018 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4019 * [Too numerous to mention...] 4020 * Verification Tag: No verification needed. 4021 * Inputs 4022 * (endpoint, asoc, chunk) 4023 * 4024 * Outputs 4025 * (asoc, reply_msg, msg_up, timers, counters) 4026 * 4027 * The return value is the disposition of the chunk. 4028 */ 4029 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 4030 const struct sctp_association *asoc, 4031 const sctp_subtype_t type, 4032 void *arg, 4033 sctp_cmd_seq_t *commands) 4034 { 4035 struct sctp_chunk *chunk = arg; 4036 4037 /* Make sure that the chunk has a valid length. 4038 * Since we don't know the chunk type, we use a general 4039 * chunkhdr structure to make a comparison. 4040 */ 4041 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4042 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4043 commands); 4044 4045 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 4046 return SCTP_DISPOSITION_DISCARD; 4047 } 4048 4049 /* 4050 * Discard the whole packet. 4051 * 4052 * Section: 8.4 2) 4053 * 4054 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4055 * silently discard the OOTB packet and take no further action. 4056 * 4057 * Verification Tag: No verification necessary 4058 * 4059 * Inputs 4060 * (endpoint, asoc, chunk) 4061 * 4062 * Outputs 4063 * (asoc, reply_msg, msg_up, timers, counters) 4064 * 4065 * The return value is the disposition of the chunk. 4066 */ 4067 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 4068 const struct sctp_association *asoc, 4069 const sctp_subtype_t type, 4070 void *arg, 4071 sctp_cmd_seq_t *commands) 4072 { 4073 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS); 4074 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4075 4076 return SCTP_DISPOSITION_CONSUME; 4077 } 4078 4079 4080 /* 4081 * The other end is violating protocol. 4082 * 4083 * Section: Not specified 4084 * Verification Tag: Not specified 4085 * Inputs 4086 * (endpoint, asoc, chunk) 4087 * 4088 * Outputs 4089 * (asoc, reply_msg, msg_up, timers, counters) 4090 * 4091 * We simply tag the chunk as a violation. The state machine will log 4092 * the violation and continue. 4093 */ 4094 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 4095 const struct sctp_association *asoc, 4096 const sctp_subtype_t type, 4097 void *arg, 4098 sctp_cmd_seq_t *commands) 4099 { 4100 struct sctp_chunk *chunk = arg; 4101 4102 /* Make sure that the chunk has a valid length. */ 4103 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4104 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4105 commands); 4106 4107 return SCTP_DISPOSITION_VIOLATION; 4108 } 4109 4110 /* 4111 * Common function to handle a protocol violation. 4112 */ 4113 static sctp_disposition_t sctp_sf_abort_violation( 4114 const struct sctp_endpoint *ep, 4115 const struct sctp_association *asoc, 4116 void *arg, 4117 sctp_cmd_seq_t *commands, 4118 const __u8 *payload, 4119 const size_t paylen) 4120 { 4121 struct sctp_packet *packet = NULL; 4122 struct sctp_chunk *chunk = arg; 4123 struct sctp_chunk *abort = NULL; 4124 4125 /* SCTP-AUTH, Section 6.3: 4126 * It should be noted that if the receiver wants to tear 4127 * down an association in an authenticated way only, the 4128 * handling of malformed packets should not result in 4129 * tearing down the association. 4130 * 4131 * This means that if we only want to abort associations 4132 * in an authenticated way (i.e AUTH+ABORT), then we 4133 * can't destory this association just becuase the packet 4134 * was malformed. 4135 */ 4136 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4137 goto discard; 4138 4139 /* Make the abort chunk. */ 4140 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4141 if (!abort) 4142 goto nomem; 4143 4144 if (asoc) { 4145 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4146 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4147 4148 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4149 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4150 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4151 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4152 SCTP_ERROR(ECONNREFUSED)); 4153 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4154 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4155 } else { 4156 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4157 SCTP_ERROR(ECONNABORTED)); 4158 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4159 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4160 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4161 } 4162 } else { 4163 packet = sctp_ootb_pkt_new(asoc, chunk); 4164 4165 if (!packet) 4166 goto nomem_pkt; 4167 4168 if (sctp_test_T_bit(abort)) 4169 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4170 4171 abort->skb->sk = ep->base.sk; 4172 4173 sctp_packet_append_chunk(packet, abort); 4174 4175 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4176 SCTP_PACKET(packet)); 4177 4178 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4179 } 4180 4181 discard: 4182 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4183 4184 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4185 4186 return SCTP_DISPOSITION_ABORT; 4187 4188 nomem_pkt: 4189 sctp_chunk_free(abort); 4190 nomem: 4191 return SCTP_DISPOSITION_NOMEM; 4192 } 4193 4194 /* 4195 * Handle a protocol violation when the chunk length is invalid. 4196 * "Invalid" length is identified as smaller then the minimal length a 4197 * given chunk can be. For example, a SACK chunk has invalid length 4198 * if it's length is set to be smaller then the size of sctp_sack_chunk_t. 4199 * 4200 * We inform the other end by sending an ABORT with a Protocol Violation 4201 * error code. 4202 * 4203 * Section: Not specified 4204 * Verification Tag: Nothing to do 4205 * Inputs 4206 * (endpoint, asoc, chunk) 4207 * 4208 * Outputs 4209 * (reply_msg, msg_up, counters) 4210 * 4211 * Generate an ABORT chunk and terminate the association. 4212 */ 4213 static sctp_disposition_t sctp_sf_violation_chunklen( 4214 const struct sctp_endpoint *ep, 4215 const struct sctp_association *asoc, 4216 const sctp_subtype_t type, 4217 void *arg, 4218 sctp_cmd_seq_t *commands) 4219 { 4220 char err_str[]="The following chunk had invalid length:"; 4221 4222 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4223 sizeof(err_str)); 4224 } 4225 4226 /* 4227 * Handle a protocol violation when the parameter length is invalid. 4228 * "Invalid" length is identified as smaller then the minimal length a 4229 * given parameter can be. 4230 */ 4231 static sctp_disposition_t sctp_sf_violation_paramlen( 4232 const struct sctp_endpoint *ep, 4233 const struct sctp_association *asoc, 4234 const sctp_subtype_t type, 4235 void *arg, 4236 sctp_cmd_seq_t *commands) { 4237 char err_str[] = "The following parameter had invalid length:"; 4238 4239 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4240 sizeof(err_str)); 4241 } 4242 4243 /* Handle a protocol violation when the peer trying to advance the 4244 * cumulative tsn ack to a point beyond the max tsn currently sent. 4245 * 4246 * We inform the other end by sending an ABORT with a Protocol Violation 4247 * error code. 4248 */ 4249 static sctp_disposition_t sctp_sf_violation_ctsn( 4250 const struct sctp_endpoint *ep, 4251 const struct sctp_association *asoc, 4252 const sctp_subtype_t type, 4253 void *arg, 4254 sctp_cmd_seq_t *commands) 4255 { 4256 char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4257 4258 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4259 sizeof(err_str)); 4260 } 4261 4262 /* Handle protocol violation of an invalid chunk bundling. For example, 4263 * when we have an association and we recieve bundled INIT-ACK, or 4264 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4265 * statement from the specs. Additinally, there might be an attacker 4266 * on the path and we may not want to continue this communication. 4267 */ 4268 static sctp_disposition_t sctp_sf_violation_chunk( 4269 const struct sctp_endpoint *ep, 4270 const struct sctp_association *asoc, 4271 const sctp_subtype_t type, 4272 void *arg, 4273 sctp_cmd_seq_t *commands) 4274 { 4275 char err_str[]="The following chunk violates protocol:"; 4276 4277 if (!asoc) 4278 return sctp_sf_violation(ep, asoc, type, arg, commands); 4279 4280 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4281 sizeof(err_str)); 4282 } 4283 /*************************************************************************** 4284 * These are the state functions for handling primitive (Section 10) events. 4285 ***************************************************************************/ 4286 /* 4287 * sctp_sf_do_prm_asoc 4288 * 4289 * Section: 10.1 ULP-to-SCTP 4290 * B) Associate 4291 * 4292 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4293 * outbound stream count) 4294 * -> association id [,destination transport addr list] [,outbound stream 4295 * count] 4296 * 4297 * This primitive allows the upper layer to initiate an association to a 4298 * specific peer endpoint. 4299 * 4300 * The peer endpoint shall be specified by one of the transport addresses 4301 * which defines the endpoint (see Section 1.4). If the local SCTP 4302 * instance has not been initialized, the ASSOCIATE is considered an 4303 * error. 4304 * [This is not relevant for the kernel implementation since we do all 4305 * initialization at boot time. It we hadn't initialized we wouldn't 4306 * get anywhere near this code.] 4307 * 4308 * An association id, which is a local handle to the SCTP association, 4309 * will be returned on successful establishment of the association. If 4310 * SCTP is not able to open an SCTP association with the peer endpoint, 4311 * an error is returned. 4312 * [In the kernel implementation, the struct sctp_association needs to 4313 * be created BEFORE causing this primitive to run.] 4314 * 4315 * Other association parameters may be returned, including the 4316 * complete destination transport addresses of the peer as well as the 4317 * outbound stream count of the local endpoint. One of the transport 4318 * address from the returned destination addresses will be selected by 4319 * the local endpoint as default primary path for sending SCTP packets 4320 * to this peer. The returned "destination transport addr list" can 4321 * be used by the ULP to change the default primary path or to force 4322 * sending a packet to a specific transport address. [All of this 4323 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4324 * function.] 4325 * 4326 * Mandatory attributes: 4327 * 4328 * o local SCTP instance name - obtained from the INITIALIZE operation. 4329 * [This is the argument asoc.] 4330 * o destination transport addr - specified as one of the transport 4331 * addresses of the peer endpoint with which the association is to be 4332 * established. 4333 * [This is asoc->peer.active_path.] 4334 * o outbound stream count - the number of outbound streams the ULP 4335 * would like to open towards this peer endpoint. 4336 * [BUG: This is not currently implemented.] 4337 * Optional attributes: 4338 * 4339 * None. 4340 * 4341 * The return value is a disposition. 4342 */ 4343 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 4344 const struct sctp_association *asoc, 4345 const sctp_subtype_t type, 4346 void *arg, 4347 sctp_cmd_seq_t *commands) 4348 { 4349 struct sctp_chunk *repl; 4350 4351 /* The comment below says that we enter COOKIE-WAIT AFTER 4352 * sending the INIT, but that doesn't actually work in our 4353 * implementation... 4354 */ 4355 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4356 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4357 4358 /* RFC 2960 5.1 Normal Establishment of an Association 4359 * 4360 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4361 * must provide its Verification Tag (Tag_A) in the Initiate 4362 * Tag field. Tag_A SHOULD be a random number in the range of 4363 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4364 */ 4365 4366 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4367 if (!repl) 4368 goto nomem; 4369 4370 /* Cast away the const modifier, as we want to just 4371 * rerun it through as a sideffect. 4372 */ 4373 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, 4374 SCTP_ASOC((struct sctp_association *) asoc)); 4375 4376 /* Choose transport for INIT. */ 4377 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4378 SCTP_CHUNK(repl)); 4379 4380 /* After sending the INIT, "A" starts the T1-init timer and 4381 * enters the COOKIE-WAIT state. 4382 */ 4383 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4384 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4385 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4386 return SCTP_DISPOSITION_CONSUME; 4387 4388 nomem: 4389 return SCTP_DISPOSITION_NOMEM; 4390 } 4391 4392 /* 4393 * Process the SEND primitive. 4394 * 4395 * Section: 10.1 ULP-to-SCTP 4396 * E) Send 4397 * 4398 * Format: SEND(association id, buffer address, byte count [,context] 4399 * [,stream id] [,life time] [,destination transport address] 4400 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4401 * -> result 4402 * 4403 * This is the main method to send user data via SCTP. 4404 * 4405 * Mandatory attributes: 4406 * 4407 * o association id - local handle to the SCTP association 4408 * 4409 * o buffer address - the location where the user message to be 4410 * transmitted is stored; 4411 * 4412 * o byte count - The size of the user data in number of bytes; 4413 * 4414 * Optional attributes: 4415 * 4416 * o context - an optional 32 bit integer that will be carried in the 4417 * sending failure notification to the ULP if the transportation of 4418 * this User Message fails. 4419 * 4420 * o stream id - to indicate which stream to send the data on. If not 4421 * specified, stream 0 will be used. 4422 * 4423 * o life time - specifies the life time of the user data. The user data 4424 * will not be sent by SCTP after the life time expires. This 4425 * parameter can be used to avoid efforts to transmit stale 4426 * user messages. SCTP notifies the ULP if the data cannot be 4427 * initiated to transport (i.e. sent to the destination via SCTP's 4428 * send primitive) within the life time variable. However, the 4429 * user data will be transmitted if SCTP has attempted to transmit a 4430 * chunk before the life time expired. 4431 * 4432 * o destination transport address - specified as one of the destination 4433 * transport addresses of the peer endpoint to which this packet 4434 * should be sent. Whenever possible, SCTP should use this destination 4435 * transport address for sending the packets, instead of the current 4436 * primary path. 4437 * 4438 * o unorder flag - this flag, if present, indicates that the user 4439 * would like the data delivered in an unordered fashion to the peer 4440 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4441 * message). 4442 * 4443 * o no-bundle flag - instructs SCTP not to bundle this user data with 4444 * other outbound DATA chunks. SCTP MAY still bundle even when 4445 * this flag is present, when faced with network congestion. 4446 * 4447 * o payload protocol-id - A 32 bit unsigned integer that is to be 4448 * passed to the peer indicating the type of payload protocol data 4449 * being transmitted. This value is passed as opaque data by SCTP. 4450 * 4451 * The return value is the disposition. 4452 */ 4453 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 4454 const struct sctp_association *asoc, 4455 const sctp_subtype_t type, 4456 void *arg, 4457 sctp_cmd_seq_t *commands) 4458 { 4459 struct sctp_chunk *chunk = arg; 4460 4461 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4462 return SCTP_DISPOSITION_CONSUME; 4463 } 4464 4465 /* 4466 * Process the SHUTDOWN primitive. 4467 * 4468 * Section: 10.1: 4469 * C) Shutdown 4470 * 4471 * Format: SHUTDOWN(association id) 4472 * -> result 4473 * 4474 * Gracefully closes an association. Any locally queued user data 4475 * will be delivered to the peer. The association will be terminated only 4476 * after the peer acknowledges all the SCTP packets sent. A success code 4477 * will be returned on successful termination of the association. If 4478 * attempting to terminate the association results in a failure, an error 4479 * code shall be returned. 4480 * 4481 * Mandatory attributes: 4482 * 4483 * o association id - local handle to the SCTP association 4484 * 4485 * Optional attributes: 4486 * 4487 * None. 4488 * 4489 * The return value is the disposition. 4490 */ 4491 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4492 const struct sctp_endpoint *ep, 4493 const struct sctp_association *asoc, 4494 const sctp_subtype_t type, 4495 void *arg, 4496 sctp_cmd_seq_t *commands) 4497 { 4498 int disposition; 4499 4500 /* From 9.2 Shutdown of an Association 4501 * Upon receipt of the SHUTDOWN primitive from its upper 4502 * layer, the endpoint enters SHUTDOWN-PENDING state and 4503 * remains there until all outstanding data has been 4504 * acknowledged by its peer. The endpoint accepts no new data 4505 * from its upper layer, but retransmits data to the far end 4506 * if necessary to fill gaps. 4507 */ 4508 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4509 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4510 4511 /* sctpimpguide-05 Section 2.12.2 4512 * The sender of the SHUTDOWN MAY also start an overall guard timer 4513 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4514 */ 4515 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4516 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4517 4518 disposition = SCTP_DISPOSITION_CONSUME; 4519 if (sctp_outq_is_empty(&asoc->outqueue)) { 4520 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4521 arg, commands); 4522 } 4523 return disposition; 4524 } 4525 4526 /* 4527 * Process the ABORT primitive. 4528 * 4529 * Section: 10.1: 4530 * C) Abort 4531 * 4532 * Format: Abort(association id [, cause code]) 4533 * -> result 4534 * 4535 * Ungracefully closes an association. Any locally queued user data 4536 * will be discarded and an ABORT chunk is sent to the peer. A success code 4537 * will be returned on successful abortion of the association. If 4538 * attempting to abort the association results in a failure, an error 4539 * code shall be returned. 4540 * 4541 * Mandatory attributes: 4542 * 4543 * o association id - local handle to the SCTP association 4544 * 4545 * Optional attributes: 4546 * 4547 * o cause code - reason of the abort to be passed to the peer 4548 * 4549 * None. 4550 * 4551 * The return value is the disposition. 4552 */ 4553 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4554 const struct sctp_endpoint *ep, 4555 const struct sctp_association *asoc, 4556 const sctp_subtype_t type, 4557 void *arg, 4558 sctp_cmd_seq_t *commands) 4559 { 4560 /* From 9.1 Abort of an Association 4561 * Upon receipt of the ABORT primitive from its upper 4562 * layer, the endpoint enters CLOSED state and 4563 * discard all outstanding data has been 4564 * acknowledged by its peer. The endpoint accepts no new data 4565 * from its upper layer, but retransmits data to the far end 4566 * if necessary to fill gaps. 4567 */ 4568 struct sctp_chunk *abort = arg; 4569 sctp_disposition_t retval; 4570 4571 retval = SCTP_DISPOSITION_CONSUME; 4572 4573 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4574 4575 /* Even if we can't send the ABORT due to low memory delete the 4576 * TCB. This is a departure from our typical NOMEM handling. 4577 */ 4578 4579 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4580 SCTP_ERROR(ECONNABORTED)); 4581 /* Delete the established association. */ 4582 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4583 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4584 4585 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4586 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4587 4588 return retval; 4589 } 4590 4591 /* We tried an illegal operation on an association which is closed. */ 4592 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4593 const struct sctp_association *asoc, 4594 const sctp_subtype_t type, 4595 void *arg, 4596 sctp_cmd_seq_t *commands) 4597 { 4598 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4599 return SCTP_DISPOSITION_CONSUME; 4600 } 4601 4602 /* We tried an illegal operation on an association which is shutting 4603 * down. 4604 */ 4605 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4606 const struct sctp_association *asoc, 4607 const sctp_subtype_t type, 4608 void *arg, 4609 sctp_cmd_seq_t *commands) 4610 { 4611 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4612 SCTP_ERROR(-ESHUTDOWN)); 4613 return SCTP_DISPOSITION_CONSUME; 4614 } 4615 4616 /* 4617 * sctp_cookie_wait_prm_shutdown 4618 * 4619 * Section: 4 Note: 2 4620 * Verification Tag: 4621 * Inputs 4622 * (endpoint, asoc) 4623 * 4624 * The RFC does not explicitly address this issue, but is the route through the 4625 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4626 * 4627 * Outputs 4628 * (timers) 4629 */ 4630 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4631 const struct sctp_endpoint *ep, 4632 const struct sctp_association *asoc, 4633 const sctp_subtype_t type, 4634 void *arg, 4635 sctp_cmd_seq_t *commands) 4636 { 4637 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4638 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4639 4640 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4641 SCTP_STATE(SCTP_STATE_CLOSED)); 4642 4643 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4644 4645 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4646 4647 return SCTP_DISPOSITION_DELETE_TCB; 4648 } 4649 4650 /* 4651 * sctp_cookie_echoed_prm_shutdown 4652 * 4653 * Section: 4 Note: 2 4654 * Verification Tag: 4655 * Inputs 4656 * (endpoint, asoc) 4657 * 4658 * The RFC does not explcitly address this issue, but is the route through the 4659 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4660 * 4661 * Outputs 4662 * (timers) 4663 */ 4664 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4665 const struct sctp_endpoint *ep, 4666 const struct sctp_association *asoc, 4667 const sctp_subtype_t type, 4668 void *arg, sctp_cmd_seq_t *commands) 4669 { 4670 /* There is a single T1 timer, so we should be able to use 4671 * common function with the COOKIE-WAIT state. 4672 */ 4673 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4674 } 4675 4676 /* 4677 * sctp_sf_cookie_wait_prm_abort 4678 * 4679 * Section: 4 Note: 2 4680 * Verification Tag: 4681 * Inputs 4682 * (endpoint, asoc) 4683 * 4684 * The RFC does not explicitly address this issue, but is the route through the 4685 * state table when someone issues an abort while in COOKIE_WAIT state. 4686 * 4687 * Outputs 4688 * (timers) 4689 */ 4690 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4691 const struct sctp_endpoint *ep, 4692 const struct sctp_association *asoc, 4693 const sctp_subtype_t type, 4694 void *arg, 4695 sctp_cmd_seq_t *commands) 4696 { 4697 struct sctp_chunk *abort = arg; 4698 sctp_disposition_t retval; 4699 4700 /* Stop T1-init timer */ 4701 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4702 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4703 retval = SCTP_DISPOSITION_CONSUME; 4704 4705 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4706 4707 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4708 SCTP_STATE(SCTP_STATE_CLOSED)); 4709 4710 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4711 4712 /* Even if we can't send the ABORT due to low memory delete the 4713 * TCB. This is a departure from our typical NOMEM handling. 4714 */ 4715 4716 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4717 SCTP_ERROR(ECONNREFUSED)); 4718 /* Delete the established association. */ 4719 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4720 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4721 4722 return retval; 4723 } 4724 4725 /* 4726 * sctp_sf_cookie_echoed_prm_abort 4727 * 4728 * Section: 4 Note: 3 4729 * Verification Tag: 4730 * Inputs 4731 * (endpoint, asoc) 4732 * 4733 * The RFC does not explcitly address this issue, but is the route through the 4734 * state table when someone issues an abort while in COOKIE_ECHOED state. 4735 * 4736 * Outputs 4737 * (timers) 4738 */ 4739 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4740 const struct sctp_endpoint *ep, 4741 const struct sctp_association *asoc, 4742 const sctp_subtype_t type, 4743 void *arg, 4744 sctp_cmd_seq_t *commands) 4745 { 4746 /* There is a single T1 timer, so we should be able to use 4747 * common function with the COOKIE-WAIT state. 4748 */ 4749 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4750 } 4751 4752 /* 4753 * sctp_sf_shutdown_pending_prm_abort 4754 * 4755 * Inputs 4756 * (endpoint, asoc) 4757 * 4758 * The RFC does not explicitly address this issue, but is the route through the 4759 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4760 * 4761 * Outputs 4762 * (timers) 4763 */ 4764 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4765 const struct sctp_endpoint *ep, 4766 const struct sctp_association *asoc, 4767 const sctp_subtype_t type, 4768 void *arg, 4769 sctp_cmd_seq_t *commands) 4770 { 4771 /* Stop the T5-shutdown guard timer. */ 4772 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4773 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4774 4775 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4776 } 4777 4778 /* 4779 * sctp_sf_shutdown_sent_prm_abort 4780 * 4781 * Inputs 4782 * (endpoint, asoc) 4783 * 4784 * The RFC does not explicitly address this issue, but is the route through the 4785 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4786 * 4787 * Outputs 4788 * (timers) 4789 */ 4790 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4791 const struct sctp_endpoint *ep, 4792 const struct sctp_association *asoc, 4793 const sctp_subtype_t type, 4794 void *arg, 4795 sctp_cmd_seq_t *commands) 4796 { 4797 /* Stop the T2-shutdown timer. */ 4798 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4799 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4800 4801 /* Stop the T5-shutdown guard timer. */ 4802 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4803 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4804 4805 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4806 } 4807 4808 /* 4809 * sctp_sf_cookie_echoed_prm_abort 4810 * 4811 * Inputs 4812 * (endpoint, asoc) 4813 * 4814 * The RFC does not explcitly address this issue, but is the route through the 4815 * state table when someone issues an abort while in COOKIE_ECHOED state. 4816 * 4817 * Outputs 4818 * (timers) 4819 */ 4820 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4821 const struct sctp_endpoint *ep, 4822 const struct sctp_association *asoc, 4823 const sctp_subtype_t type, 4824 void *arg, 4825 sctp_cmd_seq_t *commands) 4826 { 4827 /* The same T2 timer, so we should be able to use 4828 * common function with the SHUTDOWN-SENT state. 4829 */ 4830 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4831 } 4832 4833 /* 4834 * Process the REQUESTHEARTBEAT primitive 4835 * 4836 * 10.1 ULP-to-SCTP 4837 * J) Request Heartbeat 4838 * 4839 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4840 * 4841 * -> result 4842 * 4843 * Instructs the local endpoint to perform a HeartBeat on the specified 4844 * destination transport address of the given association. The returned 4845 * result should indicate whether the transmission of the HEARTBEAT 4846 * chunk to the destination address is successful. 4847 * 4848 * Mandatory attributes: 4849 * 4850 * o association id - local handle to the SCTP association 4851 * 4852 * o destination transport address - the transport address of the 4853 * association on which a heartbeat should be issued. 4854 */ 4855 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4856 const struct sctp_endpoint *ep, 4857 const struct sctp_association *asoc, 4858 const sctp_subtype_t type, 4859 void *arg, 4860 sctp_cmd_seq_t *commands) 4861 { 4862 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 4863 (struct sctp_transport *)arg, commands)) 4864 return SCTP_DISPOSITION_NOMEM; 4865 4866 /* 4867 * RFC 2960 (bis), section 8.3 4868 * 4869 * D) Request an on-demand HEARTBEAT on a specific destination 4870 * transport address of a given association. 4871 * 4872 * The endpoint should increment the respective error counter of 4873 * the destination transport address each time a HEARTBEAT is sent 4874 * to that address and not acknowledged within one RTO. 4875 * 4876 */ 4877 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 4878 SCTP_TRANSPORT(arg)); 4879 return SCTP_DISPOSITION_CONSUME; 4880 } 4881 4882 /* 4883 * ADDIP Section 4.1 ASCONF Chunk Procedures 4884 * When an endpoint has an ASCONF signaled change to be sent to the 4885 * remote endpoint it should do A1 to A9 4886 */ 4887 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 4888 const struct sctp_association *asoc, 4889 const sctp_subtype_t type, 4890 void *arg, 4891 sctp_cmd_seq_t *commands) 4892 { 4893 struct sctp_chunk *chunk = arg; 4894 4895 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4896 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4897 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4898 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4899 return SCTP_DISPOSITION_CONSUME; 4900 } 4901 4902 /* 4903 * Ignore the primitive event 4904 * 4905 * The return value is the disposition of the primitive. 4906 */ 4907 sctp_disposition_t sctp_sf_ignore_primitive( 4908 const struct sctp_endpoint *ep, 4909 const struct sctp_association *asoc, 4910 const sctp_subtype_t type, 4911 void *arg, 4912 sctp_cmd_seq_t *commands) 4913 { 4914 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 4915 return SCTP_DISPOSITION_DISCARD; 4916 } 4917 4918 /*************************************************************************** 4919 * These are the state functions for the OTHER events. 4920 ***************************************************************************/ 4921 4922 /* 4923 * Start the shutdown negotiation. 4924 * 4925 * From Section 9.2: 4926 * Once all its outstanding data has been acknowledged, the endpoint 4927 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 4928 * TSN Ack field the last sequential TSN it has received from the peer. 4929 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 4930 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 4931 * with the updated last sequential TSN received from its peer. 4932 * 4933 * The return value is the disposition. 4934 */ 4935 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 4936 const struct sctp_endpoint *ep, 4937 const struct sctp_association *asoc, 4938 const sctp_subtype_t type, 4939 void *arg, 4940 sctp_cmd_seq_t *commands) 4941 { 4942 struct sctp_chunk *reply; 4943 4944 /* Once all its outstanding data has been acknowledged, the 4945 * endpoint shall send a SHUTDOWN chunk to its peer including 4946 * in the Cumulative TSN Ack field the last sequential TSN it 4947 * has received from the peer. 4948 */ 4949 reply = sctp_make_shutdown(asoc, NULL); 4950 if (!reply) 4951 goto nomem; 4952 4953 /* Set the transport for the SHUTDOWN chunk and the timeout for the 4954 * T2-shutdown timer. 4955 */ 4956 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4957 4958 /* It shall then start the T2-shutdown timer */ 4959 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4960 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4961 4962 if (asoc->autoclose) 4963 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4964 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4965 4966 /* and enter the SHUTDOWN-SENT state. */ 4967 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4968 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 4969 4970 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4971 * 4972 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4973 * or SHUTDOWN-ACK. 4974 */ 4975 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4976 4977 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4978 4979 return SCTP_DISPOSITION_CONSUME; 4980 4981 nomem: 4982 return SCTP_DISPOSITION_NOMEM; 4983 } 4984 4985 /* 4986 * Generate a SHUTDOWN ACK now that everything is SACK'd. 4987 * 4988 * From Section 9.2: 4989 * 4990 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4991 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 4992 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 4993 * endpoint must re-send the SHUTDOWN ACK. 4994 * 4995 * The return value is the disposition. 4996 */ 4997 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 4998 const struct sctp_endpoint *ep, 4999 const struct sctp_association *asoc, 5000 const sctp_subtype_t type, 5001 void *arg, 5002 sctp_cmd_seq_t *commands) 5003 { 5004 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5005 struct sctp_chunk *reply; 5006 5007 /* There are 2 ways of getting here: 5008 * 1) called in response to a SHUTDOWN chunk 5009 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5010 * 5011 * For the case (2), the arg parameter is set to NULL. We need 5012 * to check that we have a chunk before accessing it's fields. 5013 */ 5014 if (chunk) { 5015 if (!sctp_vtag_verify(chunk, asoc)) 5016 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 5017 5018 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5019 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5020 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 5021 commands); 5022 } 5023 5024 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5025 * shall send a SHUTDOWN ACK ... 5026 */ 5027 reply = sctp_make_shutdown_ack(asoc, chunk); 5028 if (!reply) 5029 goto nomem; 5030 5031 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5032 * the T2-shutdown timer. 5033 */ 5034 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5035 5036 /* and start/restart a T2-shutdown timer of its own, */ 5037 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5038 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5039 5040 if (asoc->autoclose) 5041 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5042 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5043 5044 /* Enter the SHUTDOWN-ACK-SENT state. */ 5045 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5046 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5047 5048 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5049 * 5050 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5051 * or SHUTDOWN-ACK. 5052 */ 5053 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5054 5055 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5056 5057 return SCTP_DISPOSITION_CONSUME; 5058 5059 nomem: 5060 return SCTP_DISPOSITION_NOMEM; 5061 } 5062 5063 /* 5064 * Ignore the event defined as other 5065 * 5066 * The return value is the disposition of the event. 5067 */ 5068 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 5069 const struct sctp_association *asoc, 5070 const sctp_subtype_t type, 5071 void *arg, 5072 sctp_cmd_seq_t *commands) 5073 { 5074 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5075 return SCTP_DISPOSITION_DISCARD; 5076 } 5077 5078 /************************************************************ 5079 * These are the state functions for handling timeout events. 5080 ************************************************************/ 5081 5082 /* 5083 * RTX Timeout 5084 * 5085 * Section: 6.3.3 Handle T3-rtx Expiration 5086 * 5087 * Whenever the retransmission timer T3-rtx expires for a destination 5088 * address, do the following: 5089 * [See below] 5090 * 5091 * The return value is the disposition of the chunk. 5092 */ 5093 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 5094 const struct sctp_association *asoc, 5095 const sctp_subtype_t type, 5096 void *arg, 5097 sctp_cmd_seq_t *commands) 5098 { 5099 struct sctp_transport *transport = arg; 5100 5101 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS); 5102 5103 if (asoc->overall_error_count >= asoc->max_retrans) { 5104 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5105 SCTP_ERROR(ETIMEDOUT)); 5106 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5107 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5108 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5109 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5110 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5111 return SCTP_DISPOSITION_DELETE_TCB; 5112 } 5113 5114 /* E1) For the destination address for which the timer 5115 * expires, adjust its ssthresh with rules defined in Section 5116 * 7.2.3 and set the cwnd <- MTU. 5117 */ 5118 5119 /* E2) For the destination address for which the timer 5120 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5121 * maximum value discussed in rule C7 above (RTO.max) may be 5122 * used to provide an upper bound to this doubling operation. 5123 */ 5124 5125 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5126 * outstanding DATA chunks for the address for which the 5127 * T3-rtx has expired will fit into a single packet, subject 5128 * to the MTU constraint for the path corresponding to the 5129 * destination transport address to which the retransmission 5130 * is being sent (this may be different from the address for 5131 * which the timer expires [see Section 6.4]). Call this 5132 * value K. Bundle and retransmit those K DATA chunks in a 5133 * single packet to the destination endpoint. 5134 * 5135 * Note: Any DATA chunks that were sent to the address for 5136 * which the T3-rtx timer expired but did not fit in one MTU 5137 * (rule E3 above), should be marked for retransmission and 5138 * sent as soon as cwnd allows (normally when a SACK arrives). 5139 */ 5140 5141 /* Do some failure management (Section 8.2). */ 5142 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5143 5144 /* NB: Rules E4 and F1 are implicit in R1. */ 5145 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5146 5147 return SCTP_DISPOSITION_CONSUME; 5148 } 5149 5150 /* 5151 * Generate delayed SACK on timeout 5152 * 5153 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5154 * 5155 * The guidelines on delayed acknowledgement algorithm specified in 5156 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5157 * acknowledgement SHOULD be generated for at least every second packet 5158 * (not every second DATA chunk) received, and SHOULD be generated 5159 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5160 * some situations it may be beneficial for an SCTP transmitter to be 5161 * more conservative than the algorithms detailed in this document 5162 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5163 * the following algorithms allow. 5164 */ 5165 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 5166 const struct sctp_association *asoc, 5167 const sctp_subtype_t type, 5168 void *arg, 5169 sctp_cmd_seq_t *commands) 5170 { 5171 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS); 5172 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5173 return SCTP_DISPOSITION_CONSUME; 5174 } 5175 5176 /* 5177 * sctp_sf_t1_init_timer_expire 5178 * 5179 * Section: 4 Note: 2 5180 * Verification Tag: 5181 * Inputs 5182 * (endpoint, asoc) 5183 * 5184 * RFC 2960 Section 4 Notes 5185 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5186 * and re-start the T1-init timer without changing state. This MUST 5187 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5188 * endpoint MUST abort the initialization process and report the 5189 * error to SCTP user. 5190 * 5191 * Outputs 5192 * (timers, events) 5193 * 5194 */ 5195 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 5196 const struct sctp_association *asoc, 5197 const sctp_subtype_t type, 5198 void *arg, 5199 sctp_cmd_seq_t *commands) 5200 { 5201 struct sctp_chunk *repl = NULL; 5202 struct sctp_bind_addr *bp; 5203 int attempts = asoc->init_err_counter + 1; 5204 5205 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5206 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS); 5207 5208 if (attempts <= asoc->max_init_attempts) { 5209 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5210 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5211 if (!repl) 5212 return SCTP_DISPOSITION_NOMEM; 5213 5214 /* Choose transport for INIT. */ 5215 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5216 SCTP_CHUNK(repl)); 5217 5218 /* Issue a sideeffect to do the needed accounting. */ 5219 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5220 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5221 5222 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5223 } else { 5224 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5225 " max_init_attempts: %d\n", 5226 attempts, asoc->max_init_attempts); 5227 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5228 SCTP_ERROR(ETIMEDOUT)); 5229 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5230 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5231 return SCTP_DISPOSITION_DELETE_TCB; 5232 } 5233 5234 return SCTP_DISPOSITION_CONSUME; 5235 } 5236 5237 /* 5238 * sctp_sf_t1_cookie_timer_expire 5239 * 5240 * Section: 4 Note: 2 5241 * Verification Tag: 5242 * Inputs 5243 * (endpoint, asoc) 5244 * 5245 * RFC 2960 Section 4 Notes 5246 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5247 * COOKIE ECHO and re-start the T1-cookie timer without changing 5248 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5249 * After that, the endpoint MUST abort the initialization process and 5250 * report the error to SCTP user. 5251 * 5252 * Outputs 5253 * (timers, events) 5254 * 5255 */ 5256 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 5257 const struct sctp_association *asoc, 5258 const sctp_subtype_t type, 5259 void *arg, 5260 sctp_cmd_seq_t *commands) 5261 { 5262 struct sctp_chunk *repl = NULL; 5263 int attempts = asoc->init_err_counter + 1; 5264 5265 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5266 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS); 5267 5268 if (attempts <= asoc->max_init_attempts) { 5269 repl = sctp_make_cookie_echo(asoc, NULL); 5270 if (!repl) 5271 return SCTP_DISPOSITION_NOMEM; 5272 5273 /* Issue a sideeffect to do the needed accounting. */ 5274 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5275 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5276 5277 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5278 } else { 5279 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5280 SCTP_ERROR(ETIMEDOUT)); 5281 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5282 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5283 return SCTP_DISPOSITION_DELETE_TCB; 5284 } 5285 5286 return SCTP_DISPOSITION_CONSUME; 5287 } 5288 5289 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5290 * with the updated last sequential TSN received from its peer. 5291 * 5292 * An endpoint should limit the number of retransmissions of the 5293 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5294 * If this threshold is exceeded the endpoint should destroy the TCB and 5295 * MUST report the peer endpoint unreachable to the upper layer (and 5296 * thus the association enters the CLOSED state). The reception of any 5297 * packet from its peer (i.e. as the peer sends all of its queued DATA 5298 * chunks) should clear the endpoint's retransmission count and restart 5299 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5300 * all of its queued DATA chunks that have not yet been sent. 5301 */ 5302 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 5303 const struct sctp_association *asoc, 5304 const sctp_subtype_t type, 5305 void *arg, 5306 sctp_cmd_seq_t *commands) 5307 { 5308 struct sctp_chunk *reply = NULL; 5309 5310 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 5311 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5312 5313 if (asoc->overall_error_count >= asoc->max_retrans) { 5314 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5315 SCTP_ERROR(ETIMEDOUT)); 5316 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5317 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5318 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5319 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5320 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5321 return SCTP_DISPOSITION_DELETE_TCB; 5322 } 5323 5324 switch (asoc->state) { 5325 case SCTP_STATE_SHUTDOWN_SENT: 5326 reply = sctp_make_shutdown(asoc, NULL); 5327 break; 5328 5329 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5330 reply = sctp_make_shutdown_ack(asoc, NULL); 5331 break; 5332 5333 default: 5334 BUG(); 5335 break; 5336 } 5337 5338 if (!reply) 5339 goto nomem; 5340 5341 /* Do some failure management (Section 8.2). */ 5342 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5343 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5344 5345 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5346 * the T2-shutdown timer. 5347 */ 5348 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5349 5350 /* Restart the T2-shutdown timer. */ 5351 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5352 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5353 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5354 return SCTP_DISPOSITION_CONSUME; 5355 5356 nomem: 5357 return SCTP_DISPOSITION_NOMEM; 5358 } 5359 5360 /* 5361 * ADDIP Section 4.1 ASCONF CHunk Procedures 5362 * If the T4 RTO timer expires the endpoint should do B1 to B5 5363 */ 5364 sctp_disposition_t sctp_sf_t4_timer_expire( 5365 const struct sctp_endpoint *ep, 5366 const struct sctp_association *asoc, 5367 const sctp_subtype_t type, 5368 void *arg, 5369 sctp_cmd_seq_t *commands) 5370 { 5371 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5372 struct sctp_transport *transport = chunk->transport; 5373 5374 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS); 5375 5376 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5377 * detection on the appropriate destination address as defined in 5378 * RFC2960 [5] section 8.1 and 8.2. 5379 */ 5380 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5381 5382 /* Reconfig T4 timer and transport. */ 5383 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5384 5385 /* ADDIP 4.1 B2) Increment the association error counters and perform 5386 * endpoint failure detection on the association as defined in 5387 * RFC2960 [5] section 8.1 and 8.2. 5388 * association error counter is incremented in SCTP_CMD_STRIKE. 5389 */ 5390 if (asoc->overall_error_count >= asoc->max_retrans) { 5391 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5392 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5393 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5394 SCTP_ERROR(ETIMEDOUT)); 5395 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5396 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5397 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5398 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 5399 return SCTP_DISPOSITION_ABORT; 5400 } 5401 5402 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5403 * the ASCONF chunk was sent by doubling the RTO timer value. 5404 * This is done in SCTP_CMD_STRIKE. 5405 */ 5406 5407 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5408 * choose an alternate destination address (please refer to RFC2960 5409 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5410 * chunk, it MUST be the same (including its serial number) as the last 5411 * ASCONF sent. 5412 */ 5413 sctp_chunk_hold(asoc->addip_last_asconf); 5414 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5415 SCTP_CHUNK(asoc->addip_last_asconf)); 5416 5417 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5418 * destination is selected, then the RTO used will be that of the new 5419 * destination address. 5420 */ 5421 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5422 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5423 5424 return SCTP_DISPOSITION_CONSUME; 5425 } 5426 5427 /* sctpimpguide-05 Section 2.12.2 5428 * The sender of the SHUTDOWN MAY also start an overall guard timer 5429 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5430 * At the expiration of this timer the sender SHOULD abort the association 5431 * by sending an ABORT chunk. 5432 */ 5433 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 5434 const struct sctp_association *asoc, 5435 const sctp_subtype_t type, 5436 void *arg, 5437 sctp_cmd_seq_t *commands) 5438 { 5439 struct sctp_chunk *reply = NULL; 5440 5441 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5442 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5443 5444 reply = sctp_make_abort(asoc, NULL, 0); 5445 if (!reply) 5446 goto nomem; 5447 5448 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5449 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5450 SCTP_ERROR(ETIMEDOUT)); 5451 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5452 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5453 5454 return SCTP_DISPOSITION_DELETE_TCB; 5455 nomem: 5456 return SCTP_DISPOSITION_NOMEM; 5457 } 5458 5459 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5460 * the association is automatically closed by starting the shutdown process. 5461 * The work that needs to be done is same as when SHUTDOWN is initiated by 5462 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5463 */ 5464 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5465 const struct sctp_endpoint *ep, 5466 const struct sctp_association *asoc, 5467 const sctp_subtype_t type, 5468 void *arg, 5469 sctp_cmd_seq_t *commands) 5470 { 5471 int disposition; 5472 5473 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS); 5474 5475 /* From 9.2 Shutdown of an Association 5476 * Upon receipt of the SHUTDOWN primitive from its upper 5477 * layer, the endpoint enters SHUTDOWN-PENDING state and 5478 * remains there until all outstanding data has been 5479 * acknowledged by its peer. The endpoint accepts no new data 5480 * from its upper layer, but retransmits data to the far end 5481 * if necessary to fill gaps. 5482 */ 5483 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5484 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5485 5486 /* sctpimpguide-05 Section 2.12.2 5487 * The sender of the SHUTDOWN MAY also start an overall guard timer 5488 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5489 */ 5490 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5491 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5492 disposition = SCTP_DISPOSITION_CONSUME; 5493 if (sctp_outq_is_empty(&asoc->outqueue)) { 5494 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 5495 arg, commands); 5496 } 5497 return disposition; 5498 } 5499 5500 /***************************************************************************** 5501 * These are sa state functions which could apply to all types of events. 5502 ****************************************************************************/ 5503 5504 /* 5505 * This table entry is not implemented. 5506 * 5507 * Inputs 5508 * (endpoint, asoc, chunk) 5509 * 5510 * The return value is the disposition of the chunk. 5511 */ 5512 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 5513 const struct sctp_association *asoc, 5514 const sctp_subtype_t type, 5515 void *arg, 5516 sctp_cmd_seq_t *commands) 5517 { 5518 return SCTP_DISPOSITION_NOT_IMPL; 5519 } 5520 5521 /* 5522 * This table entry represents a bug. 5523 * 5524 * Inputs 5525 * (endpoint, asoc, chunk) 5526 * 5527 * The return value is the disposition of the chunk. 5528 */ 5529 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 5530 const struct sctp_association *asoc, 5531 const sctp_subtype_t type, 5532 void *arg, 5533 sctp_cmd_seq_t *commands) 5534 { 5535 return SCTP_DISPOSITION_BUG; 5536 } 5537 5538 /* 5539 * This table entry represents the firing of a timer in the wrong state. 5540 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5541 * when the association is in the wrong state. This event should 5542 * be ignored, so as to prevent any rearming of the timer. 5543 * 5544 * Inputs 5545 * (endpoint, asoc, chunk) 5546 * 5547 * The return value is the disposition of the chunk. 5548 */ 5549 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 5550 const struct sctp_association *asoc, 5551 const sctp_subtype_t type, 5552 void *arg, 5553 sctp_cmd_seq_t *commands) 5554 { 5555 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5556 return SCTP_DISPOSITION_CONSUME; 5557 } 5558 5559 /******************************************************************** 5560 * 2nd Level Abstractions 5561 ********************************************************************/ 5562 5563 /* Pull the SACK chunk based on the SACK header. */ 5564 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5565 { 5566 struct sctp_sackhdr *sack; 5567 unsigned int len; 5568 __u16 num_blocks; 5569 __u16 num_dup_tsns; 5570 5571 /* Protect ourselves from reading too far into 5572 * the skb from a bogus sender. 5573 */ 5574 sack = (struct sctp_sackhdr *) chunk->skb->data; 5575 5576 num_blocks = ntohs(sack->num_gap_ack_blocks); 5577 num_dup_tsns = ntohs(sack->num_dup_tsns); 5578 len = sizeof(struct sctp_sackhdr); 5579 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5580 if (len > chunk->skb->len) 5581 return NULL; 5582 5583 skb_pull(chunk->skb, len); 5584 5585 return sack; 5586 } 5587 5588 /* Create an ABORT packet to be sent as a response, with the specified 5589 * error causes. 5590 */ 5591 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5592 const struct sctp_association *asoc, 5593 struct sctp_chunk *chunk, 5594 const void *payload, 5595 size_t paylen) 5596 { 5597 struct sctp_packet *packet; 5598 struct sctp_chunk *abort; 5599 5600 packet = sctp_ootb_pkt_new(asoc, chunk); 5601 5602 if (packet) { 5603 /* Make an ABORT. 5604 * The T bit will be set if the asoc is NULL. 5605 */ 5606 abort = sctp_make_abort(asoc, chunk, paylen); 5607 if (!abort) { 5608 sctp_ootb_pkt_free(packet); 5609 return NULL; 5610 } 5611 5612 /* Reflect vtag if T-Bit is set */ 5613 if (sctp_test_T_bit(abort)) 5614 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5615 5616 /* Add specified error causes, i.e., payload, to the 5617 * end of the chunk. 5618 */ 5619 sctp_addto_chunk(abort, paylen, payload); 5620 5621 /* Set the skb to the belonging sock for accounting. */ 5622 abort->skb->sk = ep->base.sk; 5623 5624 sctp_packet_append_chunk(packet, abort); 5625 5626 } 5627 5628 return packet; 5629 } 5630 5631 /* Allocate a packet for responding in the OOTB conditions. */ 5632 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5633 const struct sctp_chunk *chunk) 5634 { 5635 struct sctp_packet *packet; 5636 struct sctp_transport *transport; 5637 __u16 sport; 5638 __u16 dport; 5639 __u32 vtag; 5640 5641 /* Get the source and destination port from the inbound packet. */ 5642 sport = ntohs(chunk->sctp_hdr->dest); 5643 dport = ntohs(chunk->sctp_hdr->source); 5644 5645 /* The V-tag is going to be the same as the inbound packet if no 5646 * association exists, otherwise, use the peer's vtag. 5647 */ 5648 if (asoc) { 5649 /* Special case the INIT-ACK as there is no peer's vtag 5650 * yet. 5651 */ 5652 switch(chunk->chunk_hdr->type) { 5653 case SCTP_CID_INIT_ACK: 5654 { 5655 sctp_initack_chunk_t *initack; 5656 5657 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5658 vtag = ntohl(initack->init_hdr.init_tag); 5659 break; 5660 } 5661 default: 5662 vtag = asoc->peer.i.init_tag; 5663 break; 5664 } 5665 } else { 5666 /* Special case the INIT and stale COOKIE_ECHO as there is no 5667 * vtag yet. 5668 */ 5669 switch(chunk->chunk_hdr->type) { 5670 case SCTP_CID_INIT: 5671 { 5672 sctp_init_chunk_t *init; 5673 5674 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5675 vtag = ntohl(init->init_hdr.init_tag); 5676 break; 5677 } 5678 default: 5679 vtag = ntohl(chunk->sctp_hdr->vtag); 5680 break; 5681 } 5682 } 5683 5684 /* Make a transport for the bucket, Eliza... */ 5685 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5686 if (!transport) 5687 goto nomem; 5688 5689 /* Cache a route for the transport with the chunk's destination as 5690 * the source address. 5691 */ 5692 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5693 sctp_sk(sctp_get_ctl_sock())); 5694 5695 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5696 packet = sctp_packet_config(packet, vtag, 0); 5697 5698 return packet; 5699 5700 nomem: 5701 return NULL; 5702 } 5703 5704 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5705 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5706 { 5707 sctp_transport_free(packet->transport); 5708 } 5709 5710 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5711 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5712 const struct sctp_association *asoc, 5713 const struct sctp_chunk *chunk, 5714 sctp_cmd_seq_t *commands, 5715 struct sctp_chunk *err_chunk) 5716 { 5717 struct sctp_packet *packet; 5718 5719 if (err_chunk) { 5720 packet = sctp_ootb_pkt_new(asoc, chunk); 5721 if (packet) { 5722 struct sctp_signed_cookie *cookie; 5723 5724 /* Override the OOTB vtag from the cookie. */ 5725 cookie = chunk->subh.cookie_hdr; 5726 packet->vtag = cookie->c.peer_vtag; 5727 5728 /* Set the skb to the belonging sock for accounting. */ 5729 err_chunk->skb->sk = ep->base.sk; 5730 sctp_packet_append_chunk(packet, err_chunk); 5731 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5732 SCTP_PACKET(packet)); 5733 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5734 } else 5735 sctp_chunk_free (err_chunk); 5736 } 5737 } 5738 5739 5740 /* Process a data chunk */ 5741 static int sctp_eat_data(const struct sctp_association *asoc, 5742 struct sctp_chunk *chunk, 5743 sctp_cmd_seq_t *commands) 5744 { 5745 sctp_datahdr_t *data_hdr; 5746 struct sctp_chunk *err; 5747 size_t datalen; 5748 sctp_verb_t deliver; 5749 int tmp; 5750 __u32 tsn; 5751 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 5752 struct sock *sk = asoc->base.sk; 5753 5754 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5755 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5756 5757 tsn = ntohl(data_hdr->tsn); 5758 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5759 5760 /* ASSERT: Now skb->data is really the user data. */ 5761 5762 /* Process ECN based congestion. 5763 * 5764 * Since the chunk structure is reused for all chunks within 5765 * a packet, we use ecn_ce_done to track if we've already 5766 * done CE processing for this packet. 5767 * 5768 * We need to do ECN processing even if we plan to discard the 5769 * chunk later. 5770 */ 5771 5772 if (!chunk->ecn_ce_done) { 5773 struct sctp_af *af; 5774 chunk->ecn_ce_done = 1; 5775 5776 af = sctp_get_af_specific( 5777 ipver2af(ip_hdr(chunk->skb)->version)); 5778 5779 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5780 /* Do real work as sideffect. */ 5781 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5782 SCTP_U32(tsn)); 5783 } 5784 } 5785 5786 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5787 if (tmp < 0) { 5788 /* The TSN is too high--silently discard the chunk and 5789 * count on it getting retransmitted later. 5790 */ 5791 return SCTP_IERROR_HIGH_TSN; 5792 } else if (tmp > 0) { 5793 /* This is a duplicate. Record it. */ 5794 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5795 return SCTP_IERROR_DUP_TSN; 5796 } 5797 5798 /* This is a new TSN. */ 5799 5800 /* Discard if there is no room in the receive window. 5801 * Actually, allow a little bit of overflow (up to a MTU). 5802 */ 5803 datalen = ntohs(chunk->chunk_hdr->length); 5804 datalen -= sizeof(sctp_data_chunk_t); 5805 5806 deliver = SCTP_CMD_CHUNK_ULP; 5807 5808 /* Think about partial delivery. */ 5809 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5810 5811 /* Even if we don't accept this chunk there is 5812 * memory pressure. 5813 */ 5814 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5815 } 5816 5817 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5818 * seems a bit troublesome in that frag_point varies based on 5819 * PMTU. In cases, such as loopback, this might be a rather 5820 * large spill over. 5821 */ 5822 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 5823 (datalen > asoc->rwnd + asoc->frag_point))) { 5824 5825 /* If this is the next TSN, consider reneging to make 5826 * room. Note: Playing nice with a confused sender. A 5827 * malicious sender can still eat up all our buffer 5828 * space and in the future we may want to detect and 5829 * do more drastic reneging. 5830 */ 5831 if (sctp_tsnmap_has_gap(map) && 5832 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5833 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5834 deliver = SCTP_CMD_RENEGE; 5835 } else { 5836 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5837 "rwnd: %d\n", tsn, datalen, 5838 asoc->rwnd); 5839 return SCTP_IERROR_IGNORE_TSN; 5840 } 5841 } 5842 5843 /* 5844 * Also try to renege to limit our memory usage in the event that 5845 * we are under memory pressure 5846 * If we can't renege, don't worry about it, the sk_rmem_schedule 5847 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 5848 * memory usage too much 5849 */ 5850 if (*sk->sk_prot_creator->memory_pressure) { 5851 if (sctp_tsnmap_has_gap(map) && 5852 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5853 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 5854 deliver = SCTP_CMD_RENEGE; 5855 } 5856 } 5857 5858 /* 5859 * Section 3.3.10.9 No User Data (9) 5860 * 5861 * Cause of error 5862 * --------------- 5863 * No User Data: This error cause is returned to the originator of a 5864 * DATA chunk if a received DATA chunk has no user data. 5865 */ 5866 if (unlikely(0 == datalen)) { 5867 err = sctp_make_abort_no_data(asoc, chunk, tsn); 5868 if (err) { 5869 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5870 SCTP_CHUNK(err)); 5871 } 5872 /* We are going to ABORT, so we might as well stop 5873 * processing the rest of the chunks in the packet. 5874 */ 5875 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 5876 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5877 SCTP_ERROR(ECONNABORTED)); 5878 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5879 SCTP_PERR(SCTP_ERROR_NO_DATA)); 5880 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5881 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5882 return SCTP_IERROR_NO_DATA; 5883 } 5884 5885 /* If definately accepting the DATA chunk, record its TSN, otherwise 5886 * wait for renege processing. 5887 */ 5888 if (SCTP_CMD_CHUNK_ULP == deliver) 5889 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 5890 5891 chunk->data_accepted = 1; 5892 5893 /* Note: Some chunks may get overcounted (if we drop) or overcounted 5894 * if we renege and the chunk arrives again. 5895 */ 5896 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 5897 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 5898 else 5899 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 5900 5901 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 5902 * 5903 * If an endpoint receive a DATA chunk with an invalid stream 5904 * identifier, it shall acknowledge the reception of the DATA chunk 5905 * following the normal procedure, immediately send an ERROR chunk 5906 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 5907 * and discard the DATA chunk. 5908 */ 5909 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { 5910 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 5911 &data_hdr->stream, 5912 sizeof(data_hdr->stream)); 5913 if (err) 5914 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5915 SCTP_CHUNK(err)); 5916 return SCTP_IERROR_BAD_STREAM; 5917 } 5918 5919 /* Send the data up to the user. Note: Schedule the 5920 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 5921 * chunk needs the updated rwnd. 5922 */ 5923 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 5924 5925 return SCTP_IERROR_NO_ERROR; 5926 } 5927