1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <lksctp-developers@lists.sourceforge.net> 32 * 33 * Or submit a bug report through the following website: 34 * http://www.sf.net/projects/lksctp 35 * 36 * Written or modified by: 37 * La Monte H.P. Yarroll <piggy@acm.org> 38 * Karl Knutson <karl@athena.chicago.il.us> 39 * Mathew Kotowsky <kotowsky@sctp.org> 40 * Sridhar Samudrala <samudrala@us.ibm.com> 41 * Jon Grimm <jgrimm@us.ibm.com> 42 * Hui Huang <hui.huang@nokia.com> 43 * Dajiang Zhang <dajiang.zhang@nokia.com> 44 * Daisy Chang <daisyc@us.ibm.com> 45 * Ardelle Fan <ardelle.fan@intel.com> 46 * Ryan Layer <rmlayer@us.ibm.com> 47 * Kevin Gao <kevin.gao@intel.com> 48 * 49 * Any bugs reported given to us we will try to fix... any fixes shared will 50 * be incorporated into the next SCTP release. 51 */ 52 53 #include <linux/types.h> 54 #include <linux/kernel.h> 55 #include <linux/ip.h> 56 #include <linux/ipv6.h> 57 #include <linux/net.h> 58 #include <linux/inet.h> 59 #include <net/sock.h> 60 #include <net/inet_ecn.h> 61 #include <linux/skbuff.h> 62 #include <net/sctp/sctp.h> 63 #include <net/sctp/sm.h> 64 #include <net/sctp/structs.h> 65 66 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 67 const struct sctp_association *asoc, 68 struct sctp_chunk *chunk, 69 const void *payload, 70 size_t paylen); 71 static int sctp_eat_data(const struct sctp_association *asoc, 72 struct sctp_chunk *chunk, 73 sctp_cmd_seq_t *commands); 74 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 75 const struct sctp_chunk *chunk); 76 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 77 const struct sctp_association *asoc, 78 const struct sctp_chunk *chunk, 79 sctp_cmd_seq_t *commands, 80 struct sctp_chunk *err_chunk); 81 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 82 const struct sctp_association *asoc, 83 const sctp_subtype_t type, 84 void *arg, 85 sctp_cmd_seq_t *commands); 86 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 87 const struct sctp_association *asoc, 88 const sctp_subtype_t type, 89 void *arg, 90 sctp_cmd_seq_t *commands); 91 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 92 const struct sctp_association *asoc, 93 const sctp_subtype_t type, 94 void *arg, 95 sctp_cmd_seq_t *commands); 96 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 97 98 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 99 __be16 error, int sk_err, 100 const struct sctp_association *asoc, 101 struct sctp_transport *transport); 102 103 static sctp_disposition_t sctp_sf_abort_violation( 104 const struct sctp_endpoint *ep, 105 const struct sctp_association *asoc, 106 void *arg, 107 sctp_cmd_seq_t *commands, 108 const __u8 *payload, 109 const size_t paylen); 110 111 static sctp_disposition_t sctp_sf_violation_chunklen( 112 const struct sctp_endpoint *ep, 113 const struct sctp_association *asoc, 114 const sctp_subtype_t type, 115 void *arg, 116 sctp_cmd_seq_t *commands); 117 118 static sctp_disposition_t sctp_sf_violation_paramlen( 119 const struct sctp_endpoint *ep, 120 const struct sctp_association *asoc, 121 const sctp_subtype_t type, 122 void *arg, void *ext, 123 sctp_cmd_seq_t *commands); 124 125 static sctp_disposition_t sctp_sf_violation_ctsn( 126 const struct sctp_endpoint *ep, 127 const struct sctp_association *asoc, 128 const sctp_subtype_t type, 129 void *arg, 130 sctp_cmd_seq_t *commands); 131 132 static sctp_disposition_t sctp_sf_violation_chunk( 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const sctp_subtype_t type, 136 void *arg, 137 sctp_cmd_seq_t *commands); 138 139 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 140 const struct sctp_association *asoc, 141 const sctp_subtype_t type, 142 struct sctp_chunk *chunk); 143 144 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 145 const struct sctp_association *asoc, 146 const sctp_subtype_t type, 147 void *arg, 148 sctp_cmd_seq_t *commands); 149 150 /* Small helper function that checks if the chunk length 151 * is of the appropriate length. The 'required_length' argument 152 * is set to be the size of a specific chunk we are testing. 153 * Return Values: 1 = Valid length 154 * 0 = Invalid length 155 * 156 */ 157 static inline int 158 sctp_chunk_length_valid(struct sctp_chunk *chunk, 159 __u16 required_length) 160 { 161 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 162 163 if (unlikely(chunk_length < required_length)) 164 return 0; 165 166 return 1; 167 } 168 169 /********************************************************** 170 * These are the state functions for handling chunk events. 171 **********************************************************/ 172 173 /* 174 * Process the final SHUTDOWN COMPLETE. 175 * 176 * Section: 4 (C) (diagram), 9.2 177 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 178 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 179 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 180 * should stop the T2-shutdown timer and remove all knowledge of the 181 * association (and thus the association enters the CLOSED state). 182 * 183 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 184 * C) Rules for packet carrying SHUTDOWN COMPLETE: 185 * ... 186 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 187 * if the Verification Tag field of the packet matches its own tag and 188 * the T bit is not set 189 * OR 190 * it is set to its peer's tag and the T bit is set in the Chunk 191 * Flags. 192 * Otherwise, the receiver MUST silently discard the packet 193 * and take no further action. An endpoint MUST ignore the 194 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 195 * 196 * Inputs 197 * (endpoint, asoc, chunk) 198 * 199 * Outputs 200 * (asoc, reply_msg, msg_up, timers, counters) 201 * 202 * The return value is the disposition of the chunk. 203 */ 204 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, 205 const struct sctp_association *asoc, 206 const sctp_subtype_t type, 207 void *arg, 208 sctp_cmd_seq_t *commands) 209 { 210 struct sctp_chunk *chunk = arg; 211 struct sctp_ulpevent *ev; 212 213 if (!sctp_vtag_verify_either(chunk, asoc)) 214 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 215 216 /* RFC 2960 6.10 Bundling 217 * 218 * An endpoint MUST NOT bundle INIT, INIT ACK or 219 * SHUTDOWN COMPLETE with any other chunks. 220 */ 221 if (!chunk->singleton) 222 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 223 224 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 225 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 226 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 227 commands); 228 229 /* RFC 2960 10.2 SCTP-to-ULP 230 * 231 * H) SHUTDOWN COMPLETE notification 232 * 233 * When SCTP completes the shutdown procedures (section 9.2) this 234 * notification is passed to the upper layer. 235 */ 236 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 237 0, 0, 0, NULL, GFP_ATOMIC); 238 if (ev) 239 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 240 SCTP_ULPEVENT(ev)); 241 242 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 243 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 244 * not the chunk should be discarded. If the endpoint is in 245 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 246 * T2-shutdown timer and remove all knowledge of the 247 * association (and thus the association enters the CLOSED 248 * state). 249 */ 250 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 251 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 252 253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 254 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 255 256 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 257 SCTP_STATE(SCTP_STATE_CLOSED)); 258 259 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 260 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 261 262 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 263 264 return SCTP_DISPOSITION_DELETE_TCB; 265 } 266 267 /* 268 * Respond to a normal INIT chunk. 269 * We are the side that is being asked for an association. 270 * 271 * Section: 5.1 Normal Establishment of an Association, B 272 * B) "Z" shall respond immediately with an INIT ACK chunk. The 273 * destination IP address of the INIT ACK MUST be set to the source 274 * IP address of the INIT to which this INIT ACK is responding. In 275 * the response, besides filling in other parameters, "Z" must set the 276 * Verification Tag field to Tag_A, and also provide its own 277 * Verification Tag (Tag_Z) in the Initiate Tag field. 278 * 279 * Verification Tag: Must be 0. 280 * 281 * Inputs 282 * (endpoint, asoc, chunk) 283 * 284 * Outputs 285 * (asoc, reply_msg, msg_up, timers, counters) 286 * 287 * The return value is the disposition of the chunk. 288 */ 289 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 290 const struct sctp_association *asoc, 291 const sctp_subtype_t type, 292 void *arg, 293 sctp_cmd_seq_t *commands) 294 { 295 struct sctp_chunk *chunk = arg; 296 struct sctp_chunk *repl; 297 struct sctp_association *new_asoc; 298 struct sctp_chunk *err_chunk; 299 struct sctp_packet *packet; 300 sctp_unrecognized_param_t *unk_param; 301 int len; 302 303 /* 6.10 Bundling 304 * An endpoint MUST NOT bundle INIT, INIT ACK or 305 * SHUTDOWN COMPLETE with any other chunks. 306 * 307 * IG Section 2.11.2 308 * Furthermore, we require that the receiver of an INIT chunk MUST 309 * enforce these rules by silently discarding an arriving packet 310 * with an INIT chunk that is bundled with other chunks. 311 */ 312 if (!chunk->singleton) 313 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 314 315 /* If the packet is an OOTB packet which is temporarily on the 316 * control endpoint, respond with an ABORT. 317 */ 318 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) { 319 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 320 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 321 } 322 323 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 324 * Tag. 325 */ 326 if (chunk->sctp_hdr->vtag != 0) 327 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 328 329 /* Make sure that the INIT chunk has a valid length. 330 * Normally, this would cause an ABORT with a Protocol Violation 331 * error, but since we don't have an association, we'll 332 * just discard the packet. 333 */ 334 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 335 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 336 337 /* If the INIT is coming toward a closing socket, we'll send back 338 * and ABORT. Essentially, this catches the race of INIT being 339 * backloged to the socket at the same time as the user isses close(). 340 * Since the socket and all its associations are going away, we 341 * can treat this OOTB 342 */ 343 if (sctp_sstate(ep->base.sk, CLOSING)) 344 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 345 346 /* Verify the INIT chunk before processing it. */ 347 err_chunk = NULL; 348 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 349 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 350 &err_chunk)) { 351 /* This chunk contains fatal error. It is to be discarded. 352 * Send an ABORT, with causes if there is any. 353 */ 354 if (err_chunk) { 355 packet = sctp_abort_pkt_new(ep, asoc, arg, 356 (__u8 *)(err_chunk->chunk_hdr) + 357 sizeof(sctp_chunkhdr_t), 358 ntohs(err_chunk->chunk_hdr->length) - 359 sizeof(sctp_chunkhdr_t)); 360 361 sctp_chunk_free(err_chunk); 362 363 if (packet) { 364 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 365 SCTP_PACKET(packet)); 366 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 367 return SCTP_DISPOSITION_CONSUME; 368 } else { 369 return SCTP_DISPOSITION_NOMEM; 370 } 371 } else { 372 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 373 commands); 374 } 375 } 376 377 /* Grab the INIT header. */ 378 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 379 380 /* Tag the variable length parameters. */ 381 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 382 383 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 384 if (!new_asoc) 385 goto nomem; 386 387 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 388 sctp_scope(sctp_source(chunk)), 389 GFP_ATOMIC) < 0) 390 goto nomem_init; 391 392 /* The call, sctp_process_init(), can fail on memory allocation. */ 393 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 394 sctp_source(chunk), 395 (sctp_init_chunk_t *)chunk->chunk_hdr, 396 GFP_ATOMIC)) 397 goto nomem_init; 398 399 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 400 401 /* If there are errors need to be reported for unknown parameters, 402 * make sure to reserve enough room in the INIT ACK for them. 403 */ 404 len = 0; 405 if (err_chunk) 406 len = ntohs(err_chunk->chunk_hdr->length) - 407 sizeof(sctp_chunkhdr_t); 408 409 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 410 if (!repl) 411 goto nomem_init; 412 413 /* If there are errors need to be reported for unknown parameters, 414 * include them in the outgoing INIT ACK as "Unrecognized parameter" 415 * parameter. 416 */ 417 if (err_chunk) { 418 /* Get the "Unrecognized parameter" parameter(s) out of the 419 * ERROR chunk generated by sctp_verify_init(). Since the 420 * error cause code for "unknown parameter" and the 421 * "Unrecognized parameter" type is the same, we can 422 * construct the parameters in INIT ACK by copying the 423 * ERROR causes over. 424 */ 425 unk_param = (sctp_unrecognized_param_t *) 426 ((__u8 *)(err_chunk->chunk_hdr) + 427 sizeof(sctp_chunkhdr_t)); 428 /* Replace the cause code with the "Unrecognized parameter" 429 * parameter type. 430 */ 431 sctp_addto_chunk(repl, len, unk_param); 432 sctp_chunk_free(err_chunk); 433 } 434 435 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 436 437 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 438 439 /* 440 * Note: After sending out INIT ACK with the State Cookie parameter, 441 * "Z" MUST NOT allocate any resources, nor keep any states for the 442 * new association. Otherwise, "Z" will be vulnerable to resource 443 * attacks. 444 */ 445 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 446 447 return SCTP_DISPOSITION_DELETE_TCB; 448 449 nomem_init: 450 sctp_association_free(new_asoc); 451 nomem: 452 if (err_chunk) 453 sctp_chunk_free(err_chunk); 454 return SCTP_DISPOSITION_NOMEM; 455 } 456 457 /* 458 * Respond to a normal INIT ACK chunk. 459 * We are the side that is initiating the association. 460 * 461 * Section: 5.1 Normal Establishment of an Association, C 462 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 463 * timer and leave COOKIE-WAIT state. "A" shall then send the State 464 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 465 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 466 * 467 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 468 * DATA chunks, but it MUST be the first chunk in the packet and 469 * until the COOKIE ACK is returned the sender MUST NOT send any 470 * other packets to the peer. 471 * 472 * Verification Tag: 3.3.3 473 * If the value of the Initiate Tag in a received INIT ACK chunk is 474 * found to be 0, the receiver MUST treat it as an error and close the 475 * association by transmitting an ABORT. 476 * 477 * Inputs 478 * (endpoint, asoc, chunk) 479 * 480 * Outputs 481 * (asoc, reply_msg, msg_up, timers, counters) 482 * 483 * The return value is the disposition of the chunk. 484 */ 485 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, 486 const struct sctp_association *asoc, 487 const sctp_subtype_t type, 488 void *arg, 489 sctp_cmd_seq_t *commands) 490 { 491 struct sctp_chunk *chunk = arg; 492 sctp_init_chunk_t *initchunk; 493 struct sctp_chunk *err_chunk; 494 struct sctp_packet *packet; 495 496 if (!sctp_vtag_verify(chunk, asoc)) 497 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 498 499 /* 6.10 Bundling 500 * An endpoint MUST NOT bundle INIT, INIT ACK or 501 * SHUTDOWN COMPLETE with any other chunks. 502 */ 503 if (!chunk->singleton) 504 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 505 506 /* Make sure that the INIT-ACK chunk has a valid length */ 507 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 508 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 509 commands); 510 /* Grab the INIT header. */ 511 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 512 513 /* Verify the INIT chunk before processing it. */ 514 err_chunk = NULL; 515 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 516 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 517 &err_chunk)) { 518 519 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 520 521 /* This chunk contains fatal error. It is to be discarded. 522 * Send an ABORT, with causes. If there are no causes, 523 * then there wasn't enough memory. Just terminate 524 * the association. 525 */ 526 if (err_chunk) { 527 packet = sctp_abort_pkt_new(ep, asoc, arg, 528 (__u8 *)(err_chunk->chunk_hdr) + 529 sizeof(sctp_chunkhdr_t), 530 ntohs(err_chunk->chunk_hdr->length) - 531 sizeof(sctp_chunkhdr_t)); 532 533 sctp_chunk_free(err_chunk); 534 535 if (packet) { 536 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 537 SCTP_PACKET(packet)); 538 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 539 error = SCTP_ERROR_INV_PARAM; 540 } 541 } 542 543 /* SCTP-AUTH, Section 6.3: 544 * It should be noted that if the receiver wants to tear 545 * down an association in an authenticated way only, the 546 * handling of malformed packets should not result in 547 * tearing down the association. 548 * 549 * This means that if we only want to abort associations 550 * in an authenticated way (i.e AUTH+ABORT), then we 551 * can't destroy this association just becuase the packet 552 * was malformed. 553 */ 554 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 555 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 556 557 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 558 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, 559 asoc, chunk->transport); 560 } 561 562 /* Tag the variable length parameters. Note that we never 563 * convert the parameters in an INIT chunk. 564 */ 565 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 566 567 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 568 569 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 570 SCTP_PEER_INIT(initchunk)); 571 572 /* Reset init error count upon receipt of INIT-ACK. */ 573 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 574 575 /* 5.1 C) "A" shall stop the T1-init timer and leave 576 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 577 * timer, and enter the COOKIE-ECHOED state. 578 */ 579 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 580 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 581 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 582 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 583 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 584 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 585 586 /* SCTP-AUTH: genereate the assocition shared keys so that 587 * we can potentially signe the COOKIE-ECHO. 588 */ 589 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 590 591 /* 5.1 C) "A" shall then send the State Cookie received in the 592 * INIT ACK chunk in a COOKIE ECHO chunk, ... 593 */ 594 /* If there is any errors to report, send the ERROR chunk generated 595 * for unknown parameters as well. 596 */ 597 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 598 SCTP_CHUNK(err_chunk)); 599 600 return SCTP_DISPOSITION_CONSUME; 601 } 602 603 /* 604 * Respond to a normal COOKIE ECHO chunk. 605 * We are the side that is being asked for an association. 606 * 607 * Section: 5.1 Normal Establishment of an Association, D 608 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 609 * with a COOKIE ACK chunk after building a TCB and moving to 610 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 611 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 612 * chunk MUST be the first chunk in the packet. 613 * 614 * IMPLEMENTATION NOTE: An implementation may choose to send the 615 * Communication Up notification to the SCTP user upon reception 616 * of a valid COOKIE ECHO chunk. 617 * 618 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 619 * D) Rules for packet carrying a COOKIE ECHO 620 * 621 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 622 * Initial Tag received in the INIT ACK. 623 * 624 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 625 * 626 * Inputs 627 * (endpoint, asoc, chunk) 628 * 629 * Outputs 630 * (asoc, reply_msg, msg_up, timers, counters) 631 * 632 * The return value is the disposition of the chunk. 633 */ 634 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, 635 const struct sctp_association *asoc, 636 const sctp_subtype_t type, void *arg, 637 sctp_cmd_seq_t *commands) 638 { 639 struct sctp_chunk *chunk = arg; 640 struct sctp_association *new_asoc; 641 sctp_init_chunk_t *peer_init; 642 struct sctp_chunk *repl; 643 struct sctp_ulpevent *ev, *ai_ev = NULL; 644 int error = 0; 645 struct sctp_chunk *err_chk_p; 646 struct sock *sk; 647 648 /* If the packet is an OOTB packet which is temporarily on the 649 * control endpoint, respond with an ABORT. 650 */ 651 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) { 652 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 653 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 654 } 655 656 /* Make sure that the COOKIE_ECHO chunk has a valid length. 657 * In this case, we check that we have enough for at least a 658 * chunk header. More detailed verification is done 659 * in sctp_unpack_cookie(). 660 */ 661 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 662 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 663 664 /* If the endpoint is not listening or if the number of associations 665 * on the TCP-style socket exceed the max backlog, respond with an 666 * ABORT. 667 */ 668 sk = ep->base.sk; 669 if (!sctp_sstate(sk, LISTENING) || 670 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 671 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 672 673 /* "Decode" the chunk. We have no optional parameters so we 674 * are in good shape. 675 */ 676 chunk->subh.cookie_hdr = 677 (struct sctp_signed_cookie *)chunk->skb->data; 678 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 679 sizeof(sctp_chunkhdr_t))) 680 goto nomem; 681 682 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 683 * "Z" will reply with a COOKIE ACK chunk after building a TCB 684 * and moving to the ESTABLISHED state. 685 */ 686 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 687 &err_chk_p); 688 689 /* FIXME: 690 * If the re-build failed, what is the proper error path 691 * from here? 692 * 693 * [We should abort the association. --piggy] 694 */ 695 if (!new_asoc) { 696 /* FIXME: Several errors are possible. A bad cookie should 697 * be silently discarded, but think about logging it too. 698 */ 699 switch (error) { 700 case -SCTP_IERROR_NOMEM: 701 goto nomem; 702 703 case -SCTP_IERROR_STALE_COOKIE: 704 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 705 err_chk_p); 706 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 707 708 case -SCTP_IERROR_BAD_SIG: 709 default: 710 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 711 } 712 } 713 714 715 /* Delay state machine commands until later. 716 * 717 * Re-build the bind address for the association is done in 718 * the sctp_unpack_cookie() already. 719 */ 720 /* This is a brand-new association, so these are not yet side 721 * effects--it is safe to run them here. 722 */ 723 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 724 725 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 726 &chunk->subh.cookie_hdr->c.peer_addr, 727 peer_init, GFP_ATOMIC)) 728 goto nomem_init; 729 730 /* SCTP-AUTH: Now that we've populate required fields in 731 * sctp_process_init, set up the assocaition shared keys as 732 * necessary so that we can potentially authenticate the ACK 733 */ 734 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 735 if (error) 736 goto nomem_init; 737 738 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 739 * is supposed to be authenticated and we have to do delayed 740 * authentication. We've just recreated the association using 741 * the information in the cookie and now it's much easier to 742 * do the authentication. 743 */ 744 if (chunk->auth_chunk) { 745 struct sctp_chunk auth; 746 sctp_ierror_t ret; 747 748 /* set-up our fake chunk so that we can process it */ 749 auth.skb = chunk->auth_chunk; 750 auth.asoc = chunk->asoc; 751 auth.sctp_hdr = chunk->sctp_hdr; 752 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 753 sizeof(sctp_chunkhdr_t)); 754 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 755 auth.transport = chunk->transport; 756 757 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth); 758 759 /* We can now safely free the auth_chunk clone */ 760 kfree_skb(chunk->auth_chunk); 761 762 if (ret != SCTP_IERROR_NO_ERROR) { 763 sctp_association_free(new_asoc); 764 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 765 } 766 } 767 768 repl = sctp_make_cookie_ack(new_asoc, chunk); 769 if (!repl) 770 goto nomem_init; 771 772 /* RFC 2960 5.1 Normal Establishment of an Association 773 * 774 * D) IMPLEMENTATION NOTE: An implementation may choose to 775 * send the Communication Up notification to the SCTP user 776 * upon reception of a valid COOKIE ECHO chunk. 777 */ 778 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 779 new_asoc->c.sinit_num_ostreams, 780 new_asoc->c.sinit_max_instreams, 781 NULL, GFP_ATOMIC); 782 if (!ev) 783 goto nomem_ev; 784 785 /* Sockets API Draft Section 5.3.1.6 786 * When a peer sends a Adaptation Layer Indication parameter , SCTP 787 * delivers this notification to inform the application that of the 788 * peers requested adaptation layer. 789 */ 790 if (new_asoc->peer.adaptation_ind) { 791 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 792 GFP_ATOMIC); 793 if (!ai_ev) 794 goto nomem_aiev; 795 } 796 797 /* Add all the state machine commands now since we've created 798 * everything. This way we don't introduce memory corruptions 799 * during side-effect processing and correclty count established 800 * associations. 801 */ 802 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 803 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 804 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 805 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 806 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 807 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 808 809 if (new_asoc->autoclose) 810 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 811 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 812 813 /* This will send the COOKIE ACK */ 814 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 815 816 /* Queue the ASSOC_CHANGE event */ 817 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 818 819 /* Send up the Adaptation Layer Indication event */ 820 if (ai_ev) 821 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 822 SCTP_ULPEVENT(ai_ev)); 823 824 return SCTP_DISPOSITION_CONSUME; 825 826 nomem_aiev: 827 sctp_ulpevent_free(ev); 828 nomem_ev: 829 sctp_chunk_free(repl); 830 nomem_init: 831 sctp_association_free(new_asoc); 832 nomem: 833 return SCTP_DISPOSITION_NOMEM; 834 } 835 836 /* 837 * Respond to a normal COOKIE ACK chunk. 838 * We are the side that is being asked for an association. 839 * 840 * RFC 2960 5.1 Normal Establishment of an Association 841 * 842 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 843 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 844 * timer. It may also notify its ULP about the successful 845 * establishment of the association with a Communication Up 846 * notification (see Section 10). 847 * 848 * Verification Tag: 849 * Inputs 850 * (endpoint, asoc, chunk) 851 * 852 * Outputs 853 * (asoc, reply_msg, msg_up, timers, counters) 854 * 855 * The return value is the disposition of the chunk. 856 */ 857 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, 858 const struct sctp_association *asoc, 859 const sctp_subtype_t type, void *arg, 860 sctp_cmd_seq_t *commands) 861 { 862 struct sctp_chunk *chunk = arg; 863 struct sctp_ulpevent *ev; 864 865 if (!sctp_vtag_verify(chunk, asoc)) 866 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 867 868 /* Verify that the chunk length for the COOKIE-ACK is OK. 869 * If we don't do this, any bundled chunks may be junked. 870 */ 871 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 872 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 873 commands); 874 875 /* Reset init error count upon receipt of COOKIE-ACK, 876 * to avoid problems with the managemement of this 877 * counter in stale cookie situations when a transition back 878 * from the COOKIE-ECHOED state to the COOKIE-WAIT 879 * state is performed. 880 */ 881 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 882 883 /* RFC 2960 5.1 Normal Establishment of an Association 884 * 885 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 886 * from the COOKIE-ECHOED state to the ESTABLISHED state, 887 * stopping the T1-cookie timer. 888 */ 889 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 890 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 891 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 892 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 893 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 894 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); 895 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 896 if (asoc->autoclose) 897 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 898 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 899 900 /* It may also notify its ULP about the successful 901 * establishment of the association with a Communication Up 902 * notification (see Section 10). 903 */ 904 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 905 0, asoc->c.sinit_num_ostreams, 906 asoc->c.sinit_max_instreams, 907 NULL, GFP_ATOMIC); 908 909 if (!ev) 910 goto nomem; 911 912 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 913 914 /* Sockets API Draft Section 5.3.1.6 915 * When a peer sends a Adaptation Layer Indication parameter , SCTP 916 * delivers this notification to inform the application that of the 917 * peers requested adaptation layer. 918 */ 919 if (asoc->peer.adaptation_ind) { 920 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 921 if (!ev) 922 goto nomem; 923 924 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 925 SCTP_ULPEVENT(ev)); 926 } 927 928 return SCTP_DISPOSITION_CONSUME; 929 nomem: 930 return SCTP_DISPOSITION_NOMEM; 931 } 932 933 /* Generate and sendout a heartbeat packet. */ 934 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 935 const struct sctp_association *asoc, 936 const sctp_subtype_t type, 937 void *arg, 938 sctp_cmd_seq_t *commands) 939 { 940 struct sctp_transport *transport = (struct sctp_transport *) arg; 941 struct sctp_chunk *reply; 942 sctp_sender_hb_info_t hbinfo; 943 size_t paylen = 0; 944 945 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; 946 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); 947 hbinfo.daddr = transport->ipaddr; 948 hbinfo.sent_at = jiffies; 949 hbinfo.hb_nonce = transport->hb_nonce; 950 951 /* Send a heartbeat to our peer. */ 952 paylen = sizeof(sctp_sender_hb_info_t); 953 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); 954 if (!reply) 955 return SCTP_DISPOSITION_NOMEM; 956 957 /* Set rto_pending indicating that an RTT measurement 958 * is started with this heartbeat chunk. 959 */ 960 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 961 SCTP_TRANSPORT(transport)); 962 963 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 964 return SCTP_DISPOSITION_CONSUME; 965 } 966 967 /* Generate a HEARTBEAT packet on the given transport. */ 968 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 969 const struct sctp_association *asoc, 970 const sctp_subtype_t type, 971 void *arg, 972 sctp_cmd_seq_t *commands) 973 { 974 struct sctp_transport *transport = (struct sctp_transport *) arg; 975 976 if (asoc->overall_error_count >= asoc->max_retrans) { 977 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 978 SCTP_ERROR(ETIMEDOUT)); 979 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 980 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 981 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 982 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 983 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 984 return SCTP_DISPOSITION_DELETE_TCB; 985 } 986 987 /* Section 3.3.5. 988 * The Sender-specific Heartbeat Info field should normally include 989 * information about the sender's current time when this HEARTBEAT 990 * chunk is sent and the destination transport address to which this 991 * HEARTBEAT is sent (see Section 8.3). 992 */ 993 994 if (transport->param_flags & SPP_HB_ENABLE) { 995 if (SCTP_DISPOSITION_NOMEM == 996 sctp_sf_heartbeat(ep, asoc, type, arg, 997 commands)) 998 return SCTP_DISPOSITION_NOMEM; 999 /* Set transport error counter and association error counter 1000 * when sending heartbeat. 1001 */ 1002 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1003 SCTP_TRANSPORT(transport)); 1004 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1005 SCTP_TRANSPORT(transport)); 1006 } 1007 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1008 SCTP_TRANSPORT(transport)); 1009 1010 return SCTP_DISPOSITION_CONSUME; 1011 } 1012 1013 /* 1014 * Process an heartbeat request. 1015 * 1016 * Section: 8.3 Path Heartbeat 1017 * The receiver of the HEARTBEAT should immediately respond with a 1018 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1019 * from the received HEARTBEAT chunk. 1020 * 1021 * Verification Tag: 8.5 Verification Tag [Normal verification] 1022 * When receiving an SCTP packet, the endpoint MUST ensure that the 1023 * value in the Verification Tag field of the received SCTP packet 1024 * matches its own Tag. If the received Verification Tag value does not 1025 * match the receiver's own tag value, the receiver shall silently 1026 * discard the packet and shall not process it any further except for 1027 * those cases listed in Section 8.5.1 below. 1028 * 1029 * Inputs 1030 * (endpoint, asoc, chunk) 1031 * 1032 * Outputs 1033 * (asoc, reply_msg, msg_up, timers, counters) 1034 * 1035 * The return value is the disposition of the chunk. 1036 */ 1037 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 1038 const struct sctp_association *asoc, 1039 const sctp_subtype_t type, 1040 void *arg, 1041 sctp_cmd_seq_t *commands) 1042 { 1043 struct sctp_chunk *chunk = arg; 1044 struct sctp_chunk *reply; 1045 size_t paylen = 0; 1046 1047 if (!sctp_vtag_verify(chunk, asoc)) 1048 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1049 1050 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1051 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1052 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1053 commands); 1054 1055 /* 8.3 The receiver of the HEARTBEAT should immediately 1056 * respond with a HEARTBEAT ACK that contains the Heartbeat 1057 * Information field copied from the received HEARTBEAT chunk. 1058 */ 1059 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1060 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1061 if (!pskb_pull(chunk->skb, paylen)) 1062 goto nomem; 1063 1064 reply = sctp_make_heartbeat_ack(asoc, chunk, 1065 chunk->subh.hb_hdr, paylen); 1066 if (!reply) 1067 goto nomem; 1068 1069 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1070 return SCTP_DISPOSITION_CONSUME; 1071 1072 nomem: 1073 return SCTP_DISPOSITION_NOMEM; 1074 } 1075 1076 /* 1077 * Process the returning HEARTBEAT ACK. 1078 * 1079 * Section: 8.3 Path Heartbeat 1080 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1081 * should clear the error counter of the destination transport 1082 * address to which the HEARTBEAT was sent, and mark the destination 1083 * transport address as active if it is not so marked. The endpoint may 1084 * optionally report to the upper layer when an inactive destination 1085 * address is marked as active due to the reception of the latest 1086 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1087 * clear the association overall error count as well (as defined 1088 * in section 8.1). 1089 * 1090 * The receiver of the HEARTBEAT ACK should also perform an RTT 1091 * measurement for that destination transport address using the time 1092 * value carried in the HEARTBEAT ACK chunk. 1093 * 1094 * Verification Tag: 8.5 Verification Tag [Normal verification] 1095 * 1096 * Inputs 1097 * (endpoint, asoc, chunk) 1098 * 1099 * Outputs 1100 * (asoc, reply_msg, msg_up, timers, counters) 1101 * 1102 * The return value is the disposition of the chunk. 1103 */ 1104 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 1105 const struct sctp_association *asoc, 1106 const sctp_subtype_t type, 1107 void *arg, 1108 sctp_cmd_seq_t *commands) 1109 { 1110 struct sctp_chunk *chunk = arg; 1111 union sctp_addr from_addr; 1112 struct sctp_transport *link; 1113 sctp_sender_hb_info_t *hbinfo; 1114 unsigned long max_interval; 1115 1116 if (!sctp_vtag_verify(chunk, asoc)) 1117 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1118 1119 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1120 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1121 sizeof(sctp_sender_hb_info_t))) 1122 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1123 commands); 1124 1125 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1126 /* Make sure that the length of the parameter is what we expect */ 1127 if (ntohs(hbinfo->param_hdr.length) != 1128 sizeof(sctp_sender_hb_info_t)) { 1129 return SCTP_DISPOSITION_DISCARD; 1130 } 1131 1132 from_addr = hbinfo->daddr; 1133 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1134 1135 /* This should never happen, but lets log it if so. */ 1136 if (unlikely(!link)) { 1137 if (from_addr.sa.sa_family == AF_INET6) { 1138 if (net_ratelimit()) 1139 printk(KERN_WARNING 1140 "%s association %p could not find address %pI6\n", 1141 __func__, 1142 asoc, 1143 &from_addr.v6.sin6_addr); 1144 } else { 1145 if (net_ratelimit()) 1146 printk(KERN_WARNING 1147 "%s association %p could not find address %pI4\n", 1148 __func__, 1149 asoc, 1150 &from_addr.v4.sin_addr.s_addr); 1151 } 1152 return SCTP_DISPOSITION_DISCARD; 1153 } 1154 1155 /* Validate the 64-bit random nonce. */ 1156 if (hbinfo->hb_nonce != link->hb_nonce) 1157 return SCTP_DISPOSITION_DISCARD; 1158 1159 max_interval = link->hbinterval + link->rto; 1160 1161 /* Check if the timestamp looks valid. */ 1162 if (time_after(hbinfo->sent_at, jiffies) || 1163 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1164 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp " 1165 "received for transport: %p\n", 1166 __func__, link); 1167 return SCTP_DISPOSITION_DISCARD; 1168 } 1169 1170 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1171 * the HEARTBEAT should clear the error counter of the 1172 * destination transport address to which the HEARTBEAT was 1173 * sent and mark the destination transport address as active if 1174 * it is not so marked. 1175 */ 1176 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1177 1178 return SCTP_DISPOSITION_CONSUME; 1179 } 1180 1181 /* Helper function to send out an abort for the restart 1182 * condition. 1183 */ 1184 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1185 struct sctp_chunk *init, 1186 sctp_cmd_seq_t *commands) 1187 { 1188 int len; 1189 struct sctp_packet *pkt; 1190 union sctp_addr_param *addrparm; 1191 struct sctp_errhdr *errhdr; 1192 struct sctp_endpoint *ep; 1193 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1194 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1195 1196 /* Build the error on the stack. We are way to malloc crazy 1197 * throughout the code today. 1198 */ 1199 errhdr = (struct sctp_errhdr *)buffer; 1200 addrparm = (union sctp_addr_param *)errhdr->variable; 1201 1202 /* Copy into a parm format. */ 1203 len = af->to_addr_param(ssa, addrparm); 1204 len += sizeof(sctp_errhdr_t); 1205 1206 errhdr->cause = SCTP_ERROR_RESTART; 1207 errhdr->length = htons(len); 1208 1209 /* Assign to the control socket. */ 1210 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1211 1212 /* Association is NULL since this may be a restart attack and we 1213 * want to send back the attacker's vtag. 1214 */ 1215 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1216 1217 if (!pkt) 1218 goto out; 1219 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1220 1221 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1222 1223 /* Discard the rest of the inbound packet. */ 1224 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1225 1226 out: 1227 /* Even if there is no memory, treat as a failure so 1228 * the packet will get dropped. 1229 */ 1230 return 0; 1231 } 1232 1233 /* A restart is occurring, check to make sure no new addresses 1234 * are being added as we may be under a takeover attack. 1235 */ 1236 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1237 const struct sctp_association *asoc, 1238 struct sctp_chunk *init, 1239 sctp_cmd_seq_t *commands) 1240 { 1241 struct sctp_transport *new_addr, *addr; 1242 int found; 1243 1244 /* Implementor's Guide - Sectin 5.2.2 1245 * ... 1246 * Before responding the endpoint MUST check to see if the 1247 * unexpected INIT adds new addresses to the association. If new 1248 * addresses are added to the association, the endpoint MUST respond 1249 * with an ABORT.. 1250 */ 1251 1252 /* Search through all current addresses and make sure 1253 * we aren't adding any new ones. 1254 */ 1255 new_addr = NULL; 1256 found = 0; 1257 1258 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1259 transports) { 1260 found = 0; 1261 list_for_each_entry(addr, &asoc->peer.transport_addr_list, 1262 transports) { 1263 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1264 &addr->ipaddr)) { 1265 found = 1; 1266 break; 1267 } 1268 } 1269 if (!found) 1270 break; 1271 } 1272 1273 /* If a new address was added, ABORT the sender. */ 1274 if (!found && new_addr) { 1275 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1276 } 1277 1278 /* Return success if all addresses were found. */ 1279 return found; 1280 } 1281 1282 /* Populate the verification/tie tags based on overlapping INIT 1283 * scenario. 1284 * 1285 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1286 */ 1287 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1288 const struct sctp_association *asoc) 1289 { 1290 switch (asoc->state) { 1291 1292 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1293 1294 case SCTP_STATE_COOKIE_WAIT: 1295 new_asoc->c.my_vtag = asoc->c.my_vtag; 1296 new_asoc->c.my_ttag = asoc->c.my_vtag; 1297 new_asoc->c.peer_ttag = 0; 1298 break; 1299 1300 case SCTP_STATE_COOKIE_ECHOED: 1301 new_asoc->c.my_vtag = asoc->c.my_vtag; 1302 new_asoc->c.my_ttag = asoc->c.my_vtag; 1303 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1304 break; 1305 1306 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1307 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1308 */ 1309 default: 1310 new_asoc->c.my_ttag = asoc->c.my_vtag; 1311 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1312 break; 1313 } 1314 1315 /* Other parameters for the endpoint SHOULD be copied from the 1316 * existing parameters of the association (e.g. number of 1317 * outbound streams) into the INIT ACK and cookie. 1318 */ 1319 new_asoc->rwnd = asoc->rwnd; 1320 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1321 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1322 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1323 } 1324 1325 /* 1326 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1327 * handling action. 1328 * 1329 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1330 * 1331 * Returns value representing action to be taken. These action values 1332 * correspond to Action/Description values in RFC 2960, Table 2. 1333 */ 1334 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1335 const struct sctp_association *asoc) 1336 { 1337 /* In this case, the peer may have restarted. */ 1338 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1339 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1340 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1341 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1342 return 'A'; 1343 1344 /* Collision case B. */ 1345 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1346 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1347 (0 == asoc->c.peer_vtag))) { 1348 return 'B'; 1349 } 1350 1351 /* Collision case D. */ 1352 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1353 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1354 return 'D'; 1355 1356 /* Collision case C. */ 1357 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1358 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1359 (0 == new_asoc->c.my_ttag) && 1360 (0 == new_asoc->c.peer_ttag)) 1361 return 'C'; 1362 1363 /* No match to any of the special cases; discard this packet. */ 1364 return 'E'; 1365 } 1366 1367 /* Common helper routine for both duplicate and simulataneous INIT 1368 * chunk handling. 1369 */ 1370 static sctp_disposition_t sctp_sf_do_unexpected_init( 1371 const struct sctp_endpoint *ep, 1372 const struct sctp_association *asoc, 1373 const sctp_subtype_t type, 1374 void *arg, sctp_cmd_seq_t *commands) 1375 { 1376 sctp_disposition_t retval; 1377 struct sctp_chunk *chunk = arg; 1378 struct sctp_chunk *repl; 1379 struct sctp_association *new_asoc; 1380 struct sctp_chunk *err_chunk; 1381 struct sctp_packet *packet; 1382 sctp_unrecognized_param_t *unk_param; 1383 int len; 1384 1385 /* 6.10 Bundling 1386 * An endpoint MUST NOT bundle INIT, INIT ACK or 1387 * SHUTDOWN COMPLETE with any other chunks. 1388 * 1389 * IG Section 2.11.2 1390 * Furthermore, we require that the receiver of an INIT chunk MUST 1391 * enforce these rules by silently discarding an arriving packet 1392 * with an INIT chunk that is bundled with other chunks. 1393 */ 1394 if (!chunk->singleton) 1395 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1396 1397 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1398 * Tag. 1399 */ 1400 if (chunk->sctp_hdr->vtag != 0) 1401 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1402 1403 /* Make sure that the INIT chunk has a valid length. 1404 * In this case, we generate a protocol violation since we have 1405 * an association established. 1406 */ 1407 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1408 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1409 commands); 1410 /* Grab the INIT header. */ 1411 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1412 1413 /* Tag the variable length parameters. */ 1414 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1415 1416 /* Verify the INIT chunk before processing it. */ 1417 err_chunk = NULL; 1418 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1419 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1420 &err_chunk)) { 1421 /* This chunk contains fatal error. It is to be discarded. 1422 * Send an ABORT, with causes if there is any. 1423 */ 1424 if (err_chunk) { 1425 packet = sctp_abort_pkt_new(ep, asoc, arg, 1426 (__u8 *)(err_chunk->chunk_hdr) + 1427 sizeof(sctp_chunkhdr_t), 1428 ntohs(err_chunk->chunk_hdr->length) - 1429 sizeof(sctp_chunkhdr_t)); 1430 1431 if (packet) { 1432 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1433 SCTP_PACKET(packet)); 1434 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1435 retval = SCTP_DISPOSITION_CONSUME; 1436 } else { 1437 retval = SCTP_DISPOSITION_NOMEM; 1438 } 1439 goto cleanup; 1440 } else { 1441 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1442 commands); 1443 } 1444 } 1445 1446 /* 1447 * Other parameters for the endpoint SHOULD be copied from the 1448 * existing parameters of the association (e.g. number of 1449 * outbound streams) into the INIT ACK and cookie. 1450 * FIXME: We are copying parameters from the endpoint not the 1451 * association. 1452 */ 1453 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1454 if (!new_asoc) 1455 goto nomem; 1456 1457 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1458 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1459 goto nomem; 1460 1461 /* In the outbound INIT ACK the endpoint MUST copy its current 1462 * Verification Tag and Peers Verification tag into a reserved 1463 * place (local tie-tag and per tie-tag) within the state cookie. 1464 */ 1465 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1466 sctp_source(chunk), 1467 (sctp_init_chunk_t *)chunk->chunk_hdr, 1468 GFP_ATOMIC)) 1469 goto nomem; 1470 1471 /* Make sure no new addresses are being added during the 1472 * restart. Do not do this check for COOKIE-WAIT state, 1473 * since there are no peer addresses to check against. 1474 * Upon return an ABORT will have been sent if needed. 1475 */ 1476 if (!sctp_state(asoc, COOKIE_WAIT)) { 1477 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1478 commands)) { 1479 retval = SCTP_DISPOSITION_CONSUME; 1480 goto nomem_retval; 1481 } 1482 } 1483 1484 sctp_tietags_populate(new_asoc, asoc); 1485 1486 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1487 1488 /* If there are errors need to be reported for unknown parameters, 1489 * make sure to reserve enough room in the INIT ACK for them. 1490 */ 1491 len = 0; 1492 if (err_chunk) { 1493 len = ntohs(err_chunk->chunk_hdr->length) - 1494 sizeof(sctp_chunkhdr_t); 1495 } 1496 1497 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1498 if (!repl) 1499 goto nomem; 1500 1501 /* If there are errors need to be reported for unknown parameters, 1502 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1503 * parameter. 1504 */ 1505 if (err_chunk) { 1506 /* Get the "Unrecognized parameter" parameter(s) out of the 1507 * ERROR chunk generated by sctp_verify_init(). Since the 1508 * error cause code for "unknown parameter" and the 1509 * "Unrecognized parameter" type is the same, we can 1510 * construct the parameters in INIT ACK by copying the 1511 * ERROR causes over. 1512 */ 1513 unk_param = (sctp_unrecognized_param_t *) 1514 ((__u8 *)(err_chunk->chunk_hdr) + 1515 sizeof(sctp_chunkhdr_t)); 1516 /* Replace the cause code with the "Unrecognized parameter" 1517 * parameter type. 1518 */ 1519 sctp_addto_chunk(repl, len, unk_param); 1520 } 1521 1522 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1523 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1524 1525 /* 1526 * Note: After sending out INIT ACK with the State Cookie parameter, 1527 * "Z" MUST NOT allocate any resources for this new association. 1528 * Otherwise, "Z" will be vulnerable to resource attacks. 1529 */ 1530 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1531 retval = SCTP_DISPOSITION_CONSUME; 1532 1533 return retval; 1534 1535 nomem: 1536 retval = SCTP_DISPOSITION_NOMEM; 1537 nomem_retval: 1538 if (new_asoc) 1539 sctp_association_free(new_asoc); 1540 cleanup: 1541 if (err_chunk) 1542 sctp_chunk_free(err_chunk); 1543 return retval; 1544 } 1545 1546 /* 1547 * Handle simultanous INIT. 1548 * This means we started an INIT and then we got an INIT request from 1549 * our peer. 1550 * 1551 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1552 * This usually indicates an initialization collision, i.e., each 1553 * endpoint is attempting, at about the same time, to establish an 1554 * association with the other endpoint. 1555 * 1556 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1557 * endpoint MUST respond with an INIT ACK using the same parameters it 1558 * sent in its original INIT chunk (including its Verification Tag, 1559 * unchanged). These original parameters are combined with those from the 1560 * newly received INIT chunk. The endpoint shall also generate a State 1561 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1562 * INIT to calculate the State Cookie. 1563 * 1564 * After that, the endpoint MUST NOT change its state, the T1-init 1565 * timer shall be left running and the corresponding TCB MUST NOT be 1566 * destroyed. The normal procedures for handling State Cookies when 1567 * a TCB exists will resolve the duplicate INITs to a single association. 1568 * 1569 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1570 * its Tie-Tags with the Tag information of itself and its peer (see 1571 * section 5.2.2 for a description of the Tie-Tags). 1572 * 1573 * Verification Tag: Not explicit, but an INIT can not have a valid 1574 * verification tag, so we skip the check. 1575 * 1576 * Inputs 1577 * (endpoint, asoc, chunk) 1578 * 1579 * Outputs 1580 * (asoc, reply_msg, msg_up, timers, counters) 1581 * 1582 * The return value is the disposition of the chunk. 1583 */ 1584 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1585 const struct sctp_association *asoc, 1586 const sctp_subtype_t type, 1587 void *arg, 1588 sctp_cmd_seq_t *commands) 1589 { 1590 /* Call helper to do the real work for both simulataneous and 1591 * duplicate INIT chunk handling. 1592 */ 1593 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1594 } 1595 1596 /* 1597 * Handle duplicated INIT messages. These are usually delayed 1598 * restransmissions. 1599 * 1600 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1601 * COOKIE-ECHOED and COOKIE-WAIT 1602 * 1603 * Unless otherwise stated, upon reception of an unexpected INIT for 1604 * this association, the endpoint shall generate an INIT ACK with a 1605 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1606 * current Verification Tag and peer's Verification Tag into a reserved 1607 * place within the state cookie. We shall refer to these locations as 1608 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1609 * containing this INIT ACK MUST carry a Verification Tag value equal to 1610 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1611 * MUST contain a new Initiation Tag (randomly generated see Section 1612 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1613 * existing parameters of the association (e.g. number of outbound 1614 * streams) into the INIT ACK and cookie. 1615 * 1616 * After sending out the INIT ACK, the endpoint shall take no further 1617 * actions, i.e., the existing association, including its current state, 1618 * and the corresponding TCB MUST NOT be changed. 1619 * 1620 * Note: Only when a TCB exists and the association is not in a COOKIE- 1621 * WAIT state are the Tie-Tags populated. For a normal association INIT 1622 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1623 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1624 * State Cookie are populated as specified in section 5.2.1. 1625 * 1626 * Verification Tag: Not specified, but an INIT has no way of knowing 1627 * what the verification tag could be, so we ignore it. 1628 * 1629 * Inputs 1630 * (endpoint, asoc, chunk) 1631 * 1632 * Outputs 1633 * (asoc, reply_msg, msg_up, timers, counters) 1634 * 1635 * The return value is the disposition of the chunk. 1636 */ 1637 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1638 const struct sctp_association *asoc, 1639 const sctp_subtype_t type, 1640 void *arg, 1641 sctp_cmd_seq_t *commands) 1642 { 1643 /* Call helper to do the real work for both simulataneous and 1644 * duplicate INIT chunk handling. 1645 */ 1646 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1647 } 1648 1649 1650 /* 1651 * Unexpected INIT-ACK handler. 1652 * 1653 * Section 5.2.3 1654 * If an INIT ACK received by an endpoint in any state other than the 1655 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1656 * An unexpected INIT ACK usually indicates the processing of an old or 1657 * duplicated INIT chunk. 1658 */ 1659 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep, 1660 const struct sctp_association *asoc, 1661 const sctp_subtype_t type, 1662 void *arg, sctp_cmd_seq_t *commands) 1663 { 1664 /* Per the above section, we'll discard the chunk if we have an 1665 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1666 */ 1667 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 1668 return sctp_sf_ootb(ep, asoc, type, arg, commands); 1669 else 1670 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 1671 } 1672 1673 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1674 * 1675 * Section 5.2.4 1676 * A) In this case, the peer may have restarted. 1677 */ 1678 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1679 const struct sctp_association *asoc, 1680 struct sctp_chunk *chunk, 1681 sctp_cmd_seq_t *commands, 1682 struct sctp_association *new_asoc) 1683 { 1684 sctp_init_chunk_t *peer_init; 1685 struct sctp_ulpevent *ev; 1686 struct sctp_chunk *repl; 1687 struct sctp_chunk *err; 1688 sctp_disposition_t disposition; 1689 1690 /* new_asoc is a brand-new association, so these are not yet 1691 * side effects--it is safe to run them here. 1692 */ 1693 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1694 1695 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1696 sctp_source(chunk), peer_init, 1697 GFP_ATOMIC)) 1698 goto nomem; 1699 1700 /* Make sure no new addresses are being added during the 1701 * restart. Though this is a pretty complicated attack 1702 * since you'd have to get inside the cookie. 1703 */ 1704 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1705 return SCTP_DISPOSITION_CONSUME; 1706 } 1707 1708 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1709 * the peer has restarted (Action A), it MUST NOT setup a new 1710 * association but instead resend the SHUTDOWN ACK and send an ERROR 1711 * chunk with a "Cookie Received while Shutting Down" error cause to 1712 * its peer. 1713 */ 1714 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1715 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1716 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1717 chunk, commands); 1718 if (SCTP_DISPOSITION_NOMEM == disposition) 1719 goto nomem; 1720 1721 err = sctp_make_op_error(asoc, chunk, 1722 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1723 NULL, 0); 1724 if (err) 1725 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1726 SCTP_CHUNK(err)); 1727 1728 return SCTP_DISPOSITION_CONSUME; 1729 } 1730 1731 /* For now, fail any unsent/unacked data. Consider the optional 1732 * choice of resending of this data. 1733 */ 1734 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1735 1736 repl = sctp_make_cookie_ack(new_asoc, chunk); 1737 if (!repl) 1738 goto nomem; 1739 1740 /* Report association restart to upper layer. */ 1741 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1742 new_asoc->c.sinit_num_ostreams, 1743 new_asoc->c.sinit_max_instreams, 1744 NULL, GFP_ATOMIC); 1745 if (!ev) 1746 goto nomem_ev; 1747 1748 /* Update the content of current association. */ 1749 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1750 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1751 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1752 return SCTP_DISPOSITION_CONSUME; 1753 1754 nomem_ev: 1755 sctp_chunk_free(repl); 1756 nomem: 1757 return SCTP_DISPOSITION_NOMEM; 1758 } 1759 1760 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1761 * 1762 * Section 5.2.4 1763 * B) In this case, both sides may be attempting to start an association 1764 * at about the same time but the peer endpoint started its INIT 1765 * after responding to the local endpoint's INIT 1766 */ 1767 /* This case represents an initialization collision. */ 1768 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1769 const struct sctp_association *asoc, 1770 struct sctp_chunk *chunk, 1771 sctp_cmd_seq_t *commands, 1772 struct sctp_association *new_asoc) 1773 { 1774 sctp_init_chunk_t *peer_init; 1775 struct sctp_chunk *repl; 1776 1777 /* new_asoc is a brand-new association, so these are not yet 1778 * side effects--it is safe to run them here. 1779 */ 1780 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1781 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1782 sctp_source(chunk), peer_init, 1783 GFP_ATOMIC)) 1784 goto nomem; 1785 1786 /* Update the content of current association. */ 1787 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1788 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1789 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1790 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1791 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1792 1793 repl = sctp_make_cookie_ack(new_asoc, chunk); 1794 if (!repl) 1795 goto nomem; 1796 1797 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1798 1799 /* RFC 2960 5.1 Normal Establishment of an Association 1800 * 1801 * D) IMPLEMENTATION NOTE: An implementation may choose to 1802 * send the Communication Up notification to the SCTP user 1803 * upon reception of a valid COOKIE ECHO chunk. 1804 * 1805 * Sadly, this needs to be implemented as a side-effect, because 1806 * we are not guaranteed to have set the association id of the real 1807 * association and so these notifications need to be delayed until 1808 * the association id is allocated. 1809 */ 1810 1811 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1812 1813 /* Sockets API Draft Section 5.3.1.6 1814 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1815 * delivers this notification to inform the application that of the 1816 * peers requested adaptation layer. 1817 * 1818 * This also needs to be done as a side effect for the same reason as 1819 * above. 1820 */ 1821 if (asoc->peer.adaptation_ind) 1822 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1823 1824 return SCTP_DISPOSITION_CONSUME; 1825 1826 nomem: 1827 return SCTP_DISPOSITION_NOMEM; 1828 } 1829 1830 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1831 * 1832 * Section 5.2.4 1833 * C) In this case, the local endpoint's cookie has arrived late. 1834 * Before it arrived, the local endpoint sent an INIT and received an 1835 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1836 * but a new tag of its own. 1837 */ 1838 /* This case represents an initialization collision. */ 1839 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1840 const struct sctp_association *asoc, 1841 struct sctp_chunk *chunk, 1842 sctp_cmd_seq_t *commands, 1843 struct sctp_association *new_asoc) 1844 { 1845 /* The cookie should be silently discarded. 1846 * The endpoint SHOULD NOT change states and should leave 1847 * any timers running. 1848 */ 1849 return SCTP_DISPOSITION_DISCARD; 1850 } 1851 1852 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1853 * 1854 * Section 5.2.4 1855 * 1856 * D) When both local and remote tags match the endpoint should always 1857 * enter the ESTABLISHED state, if it has not already done so. 1858 */ 1859 /* This case represents an initialization collision. */ 1860 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1861 const struct sctp_association *asoc, 1862 struct sctp_chunk *chunk, 1863 sctp_cmd_seq_t *commands, 1864 struct sctp_association *new_asoc) 1865 { 1866 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1867 struct sctp_chunk *repl; 1868 1869 /* Clarification from Implementor's Guide: 1870 * D) When both local and remote tags match the endpoint should 1871 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1872 * It should stop any cookie timer that may be running and send 1873 * a COOKIE ACK. 1874 */ 1875 1876 /* Don't accidentally move back into established state. */ 1877 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1878 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1879 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1880 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1881 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1882 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1883 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1884 SCTP_NULL()); 1885 1886 /* RFC 2960 5.1 Normal Establishment of an Association 1887 * 1888 * D) IMPLEMENTATION NOTE: An implementation may choose 1889 * to send the Communication Up notification to the 1890 * SCTP user upon reception of a valid COOKIE 1891 * ECHO chunk. 1892 */ 1893 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1894 SCTP_COMM_UP, 0, 1895 asoc->c.sinit_num_ostreams, 1896 asoc->c.sinit_max_instreams, 1897 NULL, GFP_ATOMIC); 1898 if (!ev) 1899 goto nomem; 1900 1901 /* Sockets API Draft Section 5.3.1.6 1902 * When a peer sends a Adaptation Layer Indication parameter, 1903 * SCTP delivers this notification to inform the application 1904 * that of the peers requested adaptation layer. 1905 */ 1906 if (asoc->peer.adaptation_ind) { 1907 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1908 GFP_ATOMIC); 1909 if (!ai_ev) 1910 goto nomem; 1911 1912 } 1913 } 1914 1915 repl = sctp_make_cookie_ack(new_asoc, chunk); 1916 if (!repl) 1917 goto nomem; 1918 1919 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1920 1921 if (ev) 1922 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1923 SCTP_ULPEVENT(ev)); 1924 if (ai_ev) 1925 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1926 SCTP_ULPEVENT(ai_ev)); 1927 1928 return SCTP_DISPOSITION_CONSUME; 1929 1930 nomem: 1931 if (ai_ev) 1932 sctp_ulpevent_free(ai_ev); 1933 if (ev) 1934 sctp_ulpevent_free(ev); 1935 return SCTP_DISPOSITION_NOMEM; 1936 } 1937 1938 /* 1939 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1940 * chunk was retransmitted and then delayed in the network. 1941 * 1942 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1943 * 1944 * Verification Tag: None. Do cookie validation. 1945 * 1946 * Inputs 1947 * (endpoint, asoc, chunk) 1948 * 1949 * Outputs 1950 * (asoc, reply_msg, msg_up, timers, counters) 1951 * 1952 * The return value is the disposition of the chunk. 1953 */ 1954 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1955 const struct sctp_association *asoc, 1956 const sctp_subtype_t type, 1957 void *arg, 1958 sctp_cmd_seq_t *commands) 1959 { 1960 sctp_disposition_t retval; 1961 struct sctp_chunk *chunk = arg; 1962 struct sctp_association *new_asoc; 1963 int error = 0; 1964 char action; 1965 struct sctp_chunk *err_chk_p; 1966 1967 /* Make sure that the chunk has a valid length from the protocol 1968 * perspective. In this case check to make sure we have at least 1969 * enough for the chunk header. Cookie length verification is 1970 * done later. 1971 */ 1972 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1973 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1974 commands); 1975 1976 /* "Decode" the chunk. We have no optional parameters so we 1977 * are in good shape. 1978 */ 1979 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1980 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1981 sizeof(sctp_chunkhdr_t))) 1982 goto nomem; 1983 1984 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1985 * of a duplicate COOKIE ECHO match the Verification Tags of the 1986 * current association, consider the State Cookie valid even if 1987 * the lifespan is exceeded. 1988 */ 1989 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1990 &err_chk_p); 1991 1992 /* FIXME: 1993 * If the re-build failed, what is the proper error path 1994 * from here? 1995 * 1996 * [We should abort the association. --piggy] 1997 */ 1998 if (!new_asoc) { 1999 /* FIXME: Several errors are possible. A bad cookie should 2000 * be silently discarded, but think about logging it too. 2001 */ 2002 switch (error) { 2003 case -SCTP_IERROR_NOMEM: 2004 goto nomem; 2005 2006 case -SCTP_IERROR_STALE_COOKIE: 2007 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 2008 err_chk_p); 2009 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2010 case -SCTP_IERROR_BAD_SIG: 2011 default: 2012 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2013 } 2014 } 2015 2016 /* Compare the tie_tag in cookie with the verification tag of 2017 * current association. 2018 */ 2019 action = sctp_tietags_compare(new_asoc, asoc); 2020 2021 switch (action) { 2022 case 'A': /* Association restart. */ 2023 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 2024 new_asoc); 2025 break; 2026 2027 case 'B': /* Collision case B. */ 2028 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 2029 new_asoc); 2030 break; 2031 2032 case 'C': /* Collision case C. */ 2033 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 2034 new_asoc); 2035 break; 2036 2037 case 'D': /* Collision case D. */ 2038 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 2039 new_asoc); 2040 break; 2041 2042 default: /* Discard packet for all others. */ 2043 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2044 break; 2045 } 2046 2047 /* Delete the tempory new association. */ 2048 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2049 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2050 2051 return retval; 2052 2053 nomem: 2054 return SCTP_DISPOSITION_NOMEM; 2055 } 2056 2057 /* 2058 * Process an ABORT. (SHUTDOWN-PENDING state) 2059 * 2060 * See sctp_sf_do_9_1_abort(). 2061 */ 2062 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2063 const struct sctp_endpoint *ep, 2064 const struct sctp_association *asoc, 2065 const sctp_subtype_t type, 2066 void *arg, 2067 sctp_cmd_seq_t *commands) 2068 { 2069 struct sctp_chunk *chunk = arg; 2070 2071 if (!sctp_vtag_verify_either(chunk, asoc)) 2072 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2073 2074 /* Make sure that the ABORT chunk has a valid length. 2075 * Since this is an ABORT chunk, we have to discard it 2076 * because of the following text: 2077 * RFC 2960, Section 3.3.7 2078 * If an endpoint receives an ABORT with a format error or for an 2079 * association that doesn't exist, it MUST silently discard it. 2080 * Becasue the length is "invalid", we can't really discard just 2081 * as we do not know its true length. So, to be safe, discard the 2082 * packet. 2083 */ 2084 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2085 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2086 2087 /* ADD-IP: Special case for ABORT chunks 2088 * F4) One special consideration is that ABORT Chunks arriving 2089 * destined to the IP address being deleted MUST be 2090 * ignored (see Section 5.3.1 for further details). 2091 */ 2092 if (SCTP_ADDR_DEL == 2093 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2094 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2095 2096 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2097 } 2098 2099 /* 2100 * Process an ABORT. (SHUTDOWN-SENT state) 2101 * 2102 * See sctp_sf_do_9_1_abort(). 2103 */ 2104 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 2105 const struct sctp_association *asoc, 2106 const sctp_subtype_t type, 2107 void *arg, 2108 sctp_cmd_seq_t *commands) 2109 { 2110 struct sctp_chunk *chunk = arg; 2111 2112 if (!sctp_vtag_verify_either(chunk, asoc)) 2113 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2114 2115 /* Make sure that the ABORT chunk has a valid length. 2116 * Since this is an ABORT chunk, we have to discard it 2117 * because of the following text: 2118 * RFC 2960, Section 3.3.7 2119 * If an endpoint receives an ABORT with a format error or for an 2120 * association that doesn't exist, it MUST silently discard it. 2121 * Becasue the length is "invalid", we can't really discard just 2122 * as we do not know its true length. So, to be safe, discard the 2123 * packet. 2124 */ 2125 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2126 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2127 2128 /* ADD-IP: Special case for ABORT chunks 2129 * F4) One special consideration is that ABORT Chunks arriving 2130 * destined to the IP address being deleted MUST be 2131 * ignored (see Section 5.3.1 for further details). 2132 */ 2133 if (SCTP_ADDR_DEL == 2134 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2135 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2136 2137 /* Stop the T2-shutdown timer. */ 2138 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2139 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2140 2141 /* Stop the T5-shutdown guard timer. */ 2142 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2143 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2144 2145 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2146 } 2147 2148 /* 2149 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2150 * 2151 * See sctp_sf_do_9_1_abort(). 2152 */ 2153 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2154 const struct sctp_endpoint *ep, 2155 const struct sctp_association *asoc, 2156 const sctp_subtype_t type, 2157 void *arg, 2158 sctp_cmd_seq_t *commands) 2159 { 2160 /* The same T2 timer, so we should be able to use 2161 * common function with the SHUTDOWN-SENT state. 2162 */ 2163 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2164 } 2165 2166 /* 2167 * Handle an Error received in COOKIE_ECHOED state. 2168 * 2169 * Only handle the error type of stale COOKIE Error, the other errors will 2170 * be ignored. 2171 * 2172 * Inputs 2173 * (endpoint, asoc, chunk) 2174 * 2175 * Outputs 2176 * (asoc, reply_msg, msg_up, timers, counters) 2177 * 2178 * The return value is the disposition of the chunk. 2179 */ 2180 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2181 const struct sctp_association *asoc, 2182 const sctp_subtype_t type, 2183 void *arg, 2184 sctp_cmd_seq_t *commands) 2185 { 2186 struct sctp_chunk *chunk = arg; 2187 sctp_errhdr_t *err; 2188 2189 if (!sctp_vtag_verify(chunk, asoc)) 2190 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2191 2192 /* Make sure that the ERROR chunk has a valid length. 2193 * The parameter walking depends on this as well. 2194 */ 2195 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2196 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2197 commands); 2198 2199 /* Process the error here */ 2200 /* FUTURE FIXME: When PR-SCTP related and other optional 2201 * parms are emitted, this will have to change to handle multiple 2202 * errors. 2203 */ 2204 sctp_walk_errors(err, chunk->chunk_hdr) { 2205 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2206 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2207 arg, commands); 2208 } 2209 2210 /* It is possible to have malformed error causes, and that 2211 * will cause us to end the walk early. However, since 2212 * we are discarding the packet, there should be no adverse 2213 * affects. 2214 */ 2215 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2216 } 2217 2218 /* 2219 * Handle a Stale COOKIE Error 2220 * 2221 * Section: 5.2.6 Handle Stale COOKIE Error 2222 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2223 * one of the following three alternatives. 2224 * ... 2225 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2226 * Preservative parameter requesting an extension to the lifetime of 2227 * the State Cookie. When calculating the time extension, an 2228 * implementation SHOULD use the RTT information measured based on the 2229 * previous COOKIE ECHO / ERROR exchange, and should add no more 2230 * than 1 second beyond the measured RTT, due to long State Cookie 2231 * lifetimes making the endpoint more subject to a replay attack. 2232 * 2233 * Verification Tag: Not explicit, but safe to ignore. 2234 * 2235 * Inputs 2236 * (endpoint, asoc, chunk) 2237 * 2238 * Outputs 2239 * (asoc, reply_msg, msg_up, timers, counters) 2240 * 2241 * The return value is the disposition of the chunk. 2242 */ 2243 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2244 const struct sctp_association *asoc, 2245 const sctp_subtype_t type, 2246 void *arg, 2247 sctp_cmd_seq_t *commands) 2248 { 2249 struct sctp_chunk *chunk = arg; 2250 time_t stale; 2251 sctp_cookie_preserve_param_t bht; 2252 sctp_errhdr_t *err; 2253 struct sctp_chunk *reply; 2254 struct sctp_bind_addr *bp; 2255 int attempts = asoc->init_err_counter + 1; 2256 2257 if (attempts > asoc->max_init_attempts) { 2258 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2259 SCTP_ERROR(ETIMEDOUT)); 2260 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2261 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2262 return SCTP_DISPOSITION_DELETE_TCB; 2263 } 2264 2265 err = (sctp_errhdr_t *)(chunk->skb->data); 2266 2267 /* When calculating the time extension, an implementation 2268 * SHOULD use the RTT information measured based on the 2269 * previous COOKIE ECHO / ERROR exchange, and should add no 2270 * more than 1 second beyond the measured RTT, due to long 2271 * State Cookie lifetimes making the endpoint more subject to 2272 * a replay attack. 2273 * Measure of Staleness's unit is usec. (1/1000000 sec) 2274 * Suggested Cookie Life-span Increment's unit is msec. 2275 * (1/1000 sec) 2276 * In general, if you use the suggested cookie life, the value 2277 * found in the field of measure of staleness should be doubled 2278 * to give ample time to retransmit the new cookie and thus 2279 * yield a higher probability of success on the reattempt. 2280 */ 2281 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2282 stale = (stale * 2) / 1000; 2283 2284 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2285 bht.param_hdr.length = htons(sizeof(bht)); 2286 bht.lifespan_increment = htonl(stale); 2287 2288 /* Build that new INIT chunk. */ 2289 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2290 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2291 if (!reply) 2292 goto nomem; 2293 2294 sctp_addto_chunk(reply, sizeof(bht), &bht); 2295 2296 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2297 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2298 2299 /* Stop pending T3-rtx and heartbeat timers */ 2300 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2301 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2302 2303 /* Delete non-primary peer ip addresses since we are transitioning 2304 * back to the COOKIE-WAIT state 2305 */ 2306 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2307 2308 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2309 * resend 2310 */ 2311 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2312 SCTP_TRANSPORT(asoc->peer.primary_path)); 2313 2314 /* Cast away the const modifier, as we want to just 2315 * rerun it through as a sideffect. 2316 */ 2317 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2318 2319 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2320 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2321 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2322 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2323 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2324 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2325 2326 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2327 2328 return SCTP_DISPOSITION_CONSUME; 2329 2330 nomem: 2331 return SCTP_DISPOSITION_NOMEM; 2332 } 2333 2334 /* 2335 * Process an ABORT. 2336 * 2337 * Section: 9.1 2338 * After checking the Verification Tag, the receiving endpoint shall 2339 * remove the association from its record, and shall report the 2340 * termination to its upper layer. 2341 * 2342 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2343 * B) Rules for packet carrying ABORT: 2344 * 2345 * - The endpoint shall always fill in the Verification Tag field of the 2346 * outbound packet with the destination endpoint's tag value if it 2347 * is known. 2348 * 2349 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2350 * MUST follow the procedure described in Section 8.4. 2351 * 2352 * - The receiver MUST accept the packet if the Verification Tag 2353 * matches either its own tag, OR the tag of its peer. Otherwise, the 2354 * receiver MUST silently discard the packet and take no further 2355 * action. 2356 * 2357 * Inputs 2358 * (endpoint, asoc, chunk) 2359 * 2360 * Outputs 2361 * (asoc, reply_msg, msg_up, timers, counters) 2362 * 2363 * The return value is the disposition of the chunk. 2364 */ 2365 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2366 const struct sctp_association *asoc, 2367 const sctp_subtype_t type, 2368 void *arg, 2369 sctp_cmd_seq_t *commands) 2370 { 2371 struct sctp_chunk *chunk = arg; 2372 2373 if (!sctp_vtag_verify_either(chunk, asoc)) 2374 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2375 2376 /* Make sure that the ABORT chunk has a valid length. 2377 * Since this is an ABORT chunk, we have to discard it 2378 * because of the following text: 2379 * RFC 2960, Section 3.3.7 2380 * If an endpoint receives an ABORT with a format error or for an 2381 * association that doesn't exist, it MUST silently discard it. 2382 * Becasue the length is "invalid", we can't really discard just 2383 * as we do not know its true length. So, to be safe, discard the 2384 * packet. 2385 */ 2386 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2387 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2388 2389 /* ADD-IP: Special case for ABORT chunks 2390 * F4) One special consideration is that ABORT Chunks arriving 2391 * destined to the IP address being deleted MUST be 2392 * ignored (see Section 5.3.1 for further details). 2393 */ 2394 if (SCTP_ADDR_DEL == 2395 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2396 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2397 2398 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2399 } 2400 2401 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2402 const struct sctp_association *asoc, 2403 const sctp_subtype_t type, 2404 void *arg, 2405 sctp_cmd_seq_t *commands) 2406 { 2407 struct sctp_chunk *chunk = arg; 2408 unsigned len; 2409 __be16 error = SCTP_ERROR_NO_ERROR; 2410 2411 /* See if we have an error cause code in the chunk. */ 2412 len = ntohs(chunk->chunk_hdr->length); 2413 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2414 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2415 2416 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2417 /* ASSOC_FAILED will DELETE_TCB. */ 2418 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2419 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2420 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2421 2422 return SCTP_DISPOSITION_ABORT; 2423 } 2424 2425 /* 2426 * Process an ABORT. (COOKIE-WAIT state) 2427 * 2428 * See sctp_sf_do_9_1_abort() above. 2429 */ 2430 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2431 const struct sctp_association *asoc, 2432 const sctp_subtype_t type, 2433 void *arg, 2434 sctp_cmd_seq_t *commands) 2435 { 2436 struct sctp_chunk *chunk = arg; 2437 unsigned len; 2438 __be16 error = SCTP_ERROR_NO_ERROR; 2439 2440 if (!sctp_vtag_verify_either(chunk, asoc)) 2441 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2442 2443 /* Make sure that the ABORT chunk has a valid length. 2444 * Since this is an ABORT chunk, we have to discard it 2445 * because of the following text: 2446 * RFC 2960, Section 3.3.7 2447 * If an endpoint receives an ABORT with a format error or for an 2448 * association that doesn't exist, it MUST silently discard it. 2449 * Becasue the length is "invalid", we can't really discard just 2450 * as we do not know its true length. So, to be safe, discard the 2451 * packet. 2452 */ 2453 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2454 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2455 2456 /* See if we have an error cause code in the chunk. */ 2457 len = ntohs(chunk->chunk_hdr->length); 2458 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2459 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2460 2461 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, 2462 chunk->transport); 2463 } 2464 2465 /* 2466 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2467 */ 2468 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2469 const struct sctp_association *asoc, 2470 const sctp_subtype_t type, 2471 void *arg, 2472 sctp_cmd_seq_t *commands) 2473 { 2474 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, 2475 ENOPROTOOPT, asoc, 2476 (struct sctp_transport *)arg); 2477 } 2478 2479 /* 2480 * Process an ABORT. (COOKIE-ECHOED state) 2481 */ 2482 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2483 const struct sctp_association *asoc, 2484 const sctp_subtype_t type, 2485 void *arg, 2486 sctp_cmd_seq_t *commands) 2487 { 2488 /* There is a single T1 timer, so we should be able to use 2489 * common function with the COOKIE-WAIT state. 2490 */ 2491 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2492 } 2493 2494 /* 2495 * Stop T1 timer and abort association with "INIT failed". 2496 * 2497 * This is common code called by several sctp_sf_*_abort() functions above. 2498 */ 2499 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2500 __be16 error, int sk_err, 2501 const struct sctp_association *asoc, 2502 struct sctp_transport *transport) 2503 { 2504 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2505 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2506 SCTP_STATE(SCTP_STATE_CLOSED)); 2507 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2508 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2509 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2510 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2511 /* CMD_INIT_FAILED will DELETE_TCB. */ 2512 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2513 SCTP_PERR(error)); 2514 return SCTP_DISPOSITION_ABORT; 2515 } 2516 2517 /* 2518 * sctp_sf_do_9_2_shut 2519 * 2520 * Section: 9.2 2521 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2522 * - enter the SHUTDOWN-RECEIVED state, 2523 * 2524 * - stop accepting new data from its SCTP user 2525 * 2526 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2527 * that all its outstanding DATA chunks have been received by the 2528 * SHUTDOWN sender. 2529 * 2530 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2531 * send a SHUTDOWN in response to a ULP request. And should discard 2532 * subsequent SHUTDOWN chunks. 2533 * 2534 * If there are still outstanding DATA chunks left, the SHUTDOWN 2535 * receiver shall continue to follow normal data transmission 2536 * procedures defined in Section 6 until all outstanding DATA chunks 2537 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2538 * new data from its SCTP user. 2539 * 2540 * Verification Tag: 8.5 Verification Tag [Normal verification] 2541 * 2542 * Inputs 2543 * (endpoint, asoc, chunk) 2544 * 2545 * Outputs 2546 * (asoc, reply_msg, msg_up, timers, counters) 2547 * 2548 * The return value is the disposition of the chunk. 2549 */ 2550 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2551 const struct sctp_association *asoc, 2552 const sctp_subtype_t type, 2553 void *arg, 2554 sctp_cmd_seq_t *commands) 2555 { 2556 struct sctp_chunk *chunk = arg; 2557 sctp_shutdownhdr_t *sdh; 2558 sctp_disposition_t disposition; 2559 struct sctp_ulpevent *ev; 2560 __u32 ctsn; 2561 2562 if (!sctp_vtag_verify(chunk, asoc)) 2563 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2564 2565 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2566 if (!sctp_chunk_length_valid(chunk, 2567 sizeof(struct sctp_shutdown_chunk_t))) 2568 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2569 commands); 2570 2571 /* Convert the elaborate header. */ 2572 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2573 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2574 chunk->subh.shutdown_hdr = sdh; 2575 ctsn = ntohl(sdh->cum_tsn_ack); 2576 2577 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2578 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2579 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2580 return SCTP_DISPOSITION_DISCARD; 2581 } 2582 2583 /* If Cumulative TSN Ack beyond the max tsn currently 2584 * send, terminating the association and respond to the 2585 * sender with an ABORT. 2586 */ 2587 if (!TSN_lt(ctsn, asoc->next_tsn)) 2588 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 2589 2590 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2591 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2592 * inform the application that it should cease sending data. 2593 */ 2594 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2595 if (!ev) { 2596 disposition = SCTP_DISPOSITION_NOMEM; 2597 goto out; 2598 } 2599 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2600 2601 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2602 * - enter the SHUTDOWN-RECEIVED state, 2603 * - stop accepting new data from its SCTP user 2604 * 2605 * [This is implicit in the new state.] 2606 */ 2607 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2608 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2609 disposition = SCTP_DISPOSITION_CONSUME; 2610 2611 if (sctp_outq_is_empty(&asoc->outqueue)) { 2612 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2613 arg, commands); 2614 } 2615 2616 if (SCTP_DISPOSITION_NOMEM == disposition) 2617 goto out; 2618 2619 /* - verify, by checking the Cumulative TSN Ack field of the 2620 * chunk, that all its outstanding DATA chunks have been 2621 * received by the SHUTDOWN sender. 2622 */ 2623 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2624 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2625 2626 out: 2627 return disposition; 2628 } 2629 2630 /* 2631 * sctp_sf_do_9_2_shut_ctsn 2632 * 2633 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2634 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2635 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2636 * MUST be processed. 2637 */ 2638 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep, 2639 const struct sctp_association *asoc, 2640 const sctp_subtype_t type, 2641 void *arg, 2642 sctp_cmd_seq_t *commands) 2643 { 2644 struct sctp_chunk *chunk = arg; 2645 sctp_shutdownhdr_t *sdh; 2646 __u32 ctsn; 2647 2648 if (!sctp_vtag_verify(chunk, asoc)) 2649 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2650 2651 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2652 if (!sctp_chunk_length_valid(chunk, 2653 sizeof(struct sctp_shutdown_chunk_t))) 2654 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2655 commands); 2656 2657 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2658 ctsn = ntohl(sdh->cum_tsn_ack); 2659 2660 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2661 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2662 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2663 return SCTP_DISPOSITION_DISCARD; 2664 } 2665 2666 /* If Cumulative TSN Ack beyond the max tsn currently 2667 * send, terminating the association and respond to the 2668 * sender with an ABORT. 2669 */ 2670 if (!TSN_lt(ctsn, asoc->next_tsn)) 2671 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 2672 2673 /* verify, by checking the Cumulative TSN Ack field of the 2674 * chunk, that all its outstanding DATA chunks have been 2675 * received by the SHUTDOWN sender. 2676 */ 2677 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2678 SCTP_BE32(sdh->cum_tsn_ack)); 2679 2680 return SCTP_DISPOSITION_CONSUME; 2681 } 2682 2683 /* RFC 2960 9.2 2684 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2685 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2686 * transport addresses (either in the IP addresses or in the INIT chunk) 2687 * that belong to this association, it should discard the INIT chunk and 2688 * retransmit the SHUTDOWN ACK chunk. 2689 */ 2690 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2691 const struct sctp_association *asoc, 2692 const sctp_subtype_t type, 2693 void *arg, 2694 sctp_cmd_seq_t *commands) 2695 { 2696 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2697 struct sctp_chunk *reply; 2698 2699 /* Make sure that the chunk has a valid length */ 2700 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2701 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2702 commands); 2703 2704 /* Since we are not going to really process this INIT, there 2705 * is no point in verifying chunk boundries. Just generate 2706 * the SHUTDOWN ACK. 2707 */ 2708 reply = sctp_make_shutdown_ack(asoc, chunk); 2709 if (NULL == reply) 2710 goto nomem; 2711 2712 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2713 * the T2-SHUTDOWN timer. 2714 */ 2715 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2716 2717 /* and restart the T2-shutdown timer. */ 2718 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2719 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2720 2721 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2722 2723 return SCTP_DISPOSITION_CONSUME; 2724 nomem: 2725 return SCTP_DISPOSITION_NOMEM; 2726 } 2727 2728 /* 2729 * sctp_sf_do_ecn_cwr 2730 * 2731 * Section: Appendix A: Explicit Congestion Notification 2732 * 2733 * CWR: 2734 * 2735 * RFC 2481 details a specific bit for a sender to send in the header of 2736 * its next outbound TCP segment to indicate to its peer that it has 2737 * reduced its congestion window. This is termed the CWR bit. For 2738 * SCTP the same indication is made by including the CWR chunk. 2739 * This chunk contains one data element, i.e. the TSN number that 2740 * was sent in the ECNE chunk. This element represents the lowest 2741 * TSN number in the datagram that was originally marked with the 2742 * CE bit. 2743 * 2744 * Verification Tag: 8.5 Verification Tag [Normal verification] 2745 * Inputs 2746 * (endpoint, asoc, chunk) 2747 * 2748 * Outputs 2749 * (asoc, reply_msg, msg_up, timers, counters) 2750 * 2751 * The return value is the disposition of the chunk. 2752 */ 2753 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2754 const struct sctp_association *asoc, 2755 const sctp_subtype_t type, 2756 void *arg, 2757 sctp_cmd_seq_t *commands) 2758 { 2759 sctp_cwrhdr_t *cwr; 2760 struct sctp_chunk *chunk = arg; 2761 u32 lowest_tsn; 2762 2763 if (!sctp_vtag_verify(chunk, asoc)) 2764 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2765 2766 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2767 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2768 commands); 2769 2770 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2771 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2772 2773 lowest_tsn = ntohl(cwr->lowest_tsn); 2774 2775 /* Does this CWR ack the last sent congestion notification? */ 2776 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2777 /* Stop sending ECNE. */ 2778 sctp_add_cmd_sf(commands, 2779 SCTP_CMD_ECN_CWR, 2780 SCTP_U32(lowest_tsn)); 2781 } 2782 return SCTP_DISPOSITION_CONSUME; 2783 } 2784 2785 /* 2786 * sctp_sf_do_ecne 2787 * 2788 * Section: Appendix A: Explicit Congestion Notification 2789 * 2790 * ECN-Echo 2791 * 2792 * RFC 2481 details a specific bit for a receiver to send back in its 2793 * TCP acknowledgements to notify the sender of the Congestion 2794 * Experienced (CE) bit having arrived from the network. For SCTP this 2795 * same indication is made by including the ECNE chunk. This chunk 2796 * contains one data element, i.e. the lowest TSN associated with the IP 2797 * datagram marked with the CE bit..... 2798 * 2799 * Verification Tag: 8.5 Verification Tag [Normal verification] 2800 * Inputs 2801 * (endpoint, asoc, chunk) 2802 * 2803 * Outputs 2804 * (asoc, reply_msg, msg_up, timers, counters) 2805 * 2806 * The return value is the disposition of the chunk. 2807 */ 2808 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2809 const struct sctp_association *asoc, 2810 const sctp_subtype_t type, 2811 void *arg, 2812 sctp_cmd_seq_t *commands) 2813 { 2814 sctp_ecnehdr_t *ecne; 2815 struct sctp_chunk *chunk = arg; 2816 2817 if (!sctp_vtag_verify(chunk, asoc)) 2818 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2819 2820 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2821 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2822 commands); 2823 2824 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2825 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2826 2827 /* If this is a newer ECNE than the last CWR packet we sent out */ 2828 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2829 SCTP_U32(ntohl(ecne->lowest_tsn))); 2830 2831 return SCTP_DISPOSITION_CONSUME; 2832 } 2833 2834 /* 2835 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2836 * 2837 * The SCTP endpoint MUST always acknowledge the reception of each valid 2838 * DATA chunk. 2839 * 2840 * The guidelines on delayed acknowledgement algorithm specified in 2841 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2842 * acknowledgement SHOULD be generated for at least every second packet 2843 * (not every second DATA chunk) received, and SHOULD be generated within 2844 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2845 * situations it may be beneficial for an SCTP transmitter to be more 2846 * conservative than the algorithms detailed in this document allow. 2847 * However, an SCTP transmitter MUST NOT be more aggressive than the 2848 * following algorithms allow. 2849 * 2850 * A SCTP receiver MUST NOT generate more than one SACK for every 2851 * incoming packet, other than to update the offered window as the 2852 * receiving application consumes new data. 2853 * 2854 * Verification Tag: 8.5 Verification Tag [Normal verification] 2855 * 2856 * Inputs 2857 * (endpoint, asoc, chunk) 2858 * 2859 * Outputs 2860 * (asoc, reply_msg, msg_up, timers, counters) 2861 * 2862 * The return value is the disposition of the chunk. 2863 */ 2864 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2865 const struct sctp_association *asoc, 2866 const sctp_subtype_t type, 2867 void *arg, 2868 sctp_cmd_seq_t *commands) 2869 { 2870 struct sctp_chunk *chunk = arg; 2871 int error; 2872 2873 if (!sctp_vtag_verify(chunk, asoc)) { 2874 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2875 SCTP_NULL()); 2876 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2877 } 2878 2879 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2880 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2881 commands); 2882 2883 error = sctp_eat_data(asoc, chunk, commands ); 2884 switch (error) { 2885 case SCTP_IERROR_NO_ERROR: 2886 break; 2887 case SCTP_IERROR_HIGH_TSN: 2888 case SCTP_IERROR_BAD_STREAM: 2889 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2890 goto discard_noforce; 2891 case SCTP_IERROR_DUP_TSN: 2892 case SCTP_IERROR_IGNORE_TSN: 2893 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2894 goto discard_force; 2895 case SCTP_IERROR_NO_DATA: 2896 goto consume; 2897 case SCTP_IERROR_PROTO_VIOLATION: 2898 return sctp_sf_abort_violation(ep, asoc, chunk, commands, 2899 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2900 default: 2901 BUG(); 2902 } 2903 2904 if (asoc->autoclose) { 2905 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2906 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2907 } 2908 2909 /* If this is the last chunk in a packet, we need to count it 2910 * toward sack generation. Note that we need to SACK every 2911 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2912 * THEM. We elect to NOT generate SACK's if the chunk fails 2913 * the verification tag test. 2914 * 2915 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2916 * 2917 * The SCTP endpoint MUST always acknowledge the reception of 2918 * each valid DATA chunk. 2919 * 2920 * The guidelines on delayed acknowledgement algorithm 2921 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2922 * Specifically, an acknowledgement SHOULD be generated for at 2923 * least every second packet (not every second DATA chunk) 2924 * received, and SHOULD be generated within 200 ms of the 2925 * arrival of any unacknowledged DATA chunk. In some 2926 * situations it may be beneficial for an SCTP transmitter to 2927 * be more conservative than the algorithms detailed in this 2928 * document allow. However, an SCTP transmitter MUST NOT be 2929 * more aggressive than the following algorithms allow. 2930 */ 2931 if (chunk->end_of_packet) 2932 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2933 2934 return SCTP_DISPOSITION_CONSUME; 2935 2936 discard_force: 2937 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2938 * 2939 * When a packet arrives with duplicate DATA chunk(s) and with 2940 * no new DATA chunk(s), the endpoint MUST immediately send a 2941 * SACK with no delay. If a packet arrives with duplicate 2942 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2943 * MAY immediately send a SACK. Normally receipt of duplicate 2944 * DATA chunks will occur when the original SACK chunk was lost 2945 * and the peer's RTO has expired. The duplicate TSN number(s) 2946 * SHOULD be reported in the SACK as duplicate. 2947 */ 2948 /* In our case, we split the MAY SACK advice up whether or not 2949 * the last chunk is a duplicate.' 2950 */ 2951 if (chunk->end_of_packet) 2952 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2953 return SCTP_DISPOSITION_DISCARD; 2954 2955 discard_noforce: 2956 if (chunk->end_of_packet) 2957 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2958 2959 return SCTP_DISPOSITION_DISCARD; 2960 consume: 2961 return SCTP_DISPOSITION_CONSUME; 2962 2963 } 2964 2965 /* 2966 * sctp_sf_eat_data_fast_4_4 2967 * 2968 * Section: 4 (4) 2969 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2970 * DATA chunks without delay. 2971 * 2972 * Verification Tag: 8.5 Verification Tag [Normal verification] 2973 * Inputs 2974 * (endpoint, asoc, chunk) 2975 * 2976 * Outputs 2977 * (asoc, reply_msg, msg_up, timers, counters) 2978 * 2979 * The return value is the disposition of the chunk. 2980 */ 2981 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2982 const struct sctp_association *asoc, 2983 const sctp_subtype_t type, 2984 void *arg, 2985 sctp_cmd_seq_t *commands) 2986 { 2987 struct sctp_chunk *chunk = arg; 2988 int error; 2989 2990 if (!sctp_vtag_verify(chunk, asoc)) { 2991 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2992 SCTP_NULL()); 2993 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2994 } 2995 2996 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2997 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2998 commands); 2999 3000 error = sctp_eat_data(asoc, chunk, commands ); 3001 switch (error) { 3002 case SCTP_IERROR_NO_ERROR: 3003 case SCTP_IERROR_HIGH_TSN: 3004 case SCTP_IERROR_DUP_TSN: 3005 case SCTP_IERROR_IGNORE_TSN: 3006 case SCTP_IERROR_BAD_STREAM: 3007 break; 3008 case SCTP_IERROR_NO_DATA: 3009 goto consume; 3010 case SCTP_IERROR_PROTO_VIOLATION: 3011 return sctp_sf_abort_violation(ep, asoc, chunk, commands, 3012 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3013 default: 3014 BUG(); 3015 } 3016 3017 /* Go a head and force a SACK, since we are shutting down. */ 3018 3019 /* Implementor's Guide. 3020 * 3021 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3022 * respond to each received packet containing one or more DATA chunk(s) 3023 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3024 */ 3025 if (chunk->end_of_packet) { 3026 /* We must delay the chunk creation since the cumulative 3027 * TSN has not been updated yet. 3028 */ 3029 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3030 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3031 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3032 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3033 } 3034 3035 consume: 3036 return SCTP_DISPOSITION_CONSUME; 3037 } 3038 3039 /* 3040 * Section: 6.2 Processing a Received SACK 3041 * D) Any time a SACK arrives, the endpoint performs the following: 3042 * 3043 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3044 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3045 * increasing, a SACK whose Cumulative TSN Ack is less than the 3046 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3047 * 3048 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3049 * of bytes still outstanding after processing the Cumulative TSN Ack 3050 * and the Gap Ack Blocks. 3051 * 3052 * iii) If the SACK is missing a TSN that was previously 3053 * acknowledged via a Gap Ack Block (e.g., the data receiver 3054 * reneged on the data), then mark the corresponding DATA chunk 3055 * as available for retransmit: Mark it as missing for fast 3056 * retransmit as described in Section 7.2.4 and if no retransmit 3057 * timer is running for the destination address to which the DATA 3058 * chunk was originally transmitted, then T3-rtx is started for 3059 * that destination address. 3060 * 3061 * Verification Tag: 8.5 Verification Tag [Normal verification] 3062 * 3063 * Inputs 3064 * (endpoint, asoc, chunk) 3065 * 3066 * Outputs 3067 * (asoc, reply_msg, msg_up, timers, counters) 3068 * 3069 * The return value is the disposition of the chunk. 3070 */ 3071 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 3072 const struct sctp_association *asoc, 3073 const sctp_subtype_t type, 3074 void *arg, 3075 sctp_cmd_seq_t *commands) 3076 { 3077 struct sctp_chunk *chunk = arg; 3078 sctp_sackhdr_t *sackh; 3079 __u32 ctsn; 3080 3081 if (!sctp_vtag_verify(chunk, asoc)) 3082 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3083 3084 /* Make sure that the SACK chunk has a valid length. */ 3085 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3086 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3087 commands); 3088 3089 /* Pull the SACK chunk from the data buffer */ 3090 sackh = sctp_sm_pull_sack(chunk); 3091 /* Was this a bogus SACK? */ 3092 if (!sackh) 3093 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3094 chunk->subh.sack_hdr = sackh; 3095 ctsn = ntohl(sackh->cum_tsn_ack); 3096 3097 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3098 * Ack Point, then drop the SACK. Since Cumulative TSN 3099 * Ack is monotonically increasing, a SACK whose 3100 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3101 * Point indicates an out-of-order SACK. 3102 */ 3103 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3104 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3105 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3106 return SCTP_DISPOSITION_DISCARD; 3107 } 3108 3109 /* If Cumulative TSN Ack beyond the max tsn currently 3110 * send, terminating the association and respond to the 3111 * sender with an ABORT. 3112 */ 3113 if (!TSN_lt(ctsn, asoc->next_tsn)) 3114 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 3115 3116 /* Return this SACK for further processing. */ 3117 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 3118 3119 /* Note: We do the rest of the work on the PROCESS_SACK 3120 * sideeffect. 3121 */ 3122 return SCTP_DISPOSITION_CONSUME; 3123 } 3124 3125 /* 3126 * Generate an ABORT in response to a packet. 3127 * 3128 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3129 * 3130 * 8) The receiver should respond to the sender of the OOTB packet with 3131 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3132 * MUST fill in the Verification Tag field of the outbound packet 3133 * with the value found in the Verification Tag field of the OOTB 3134 * packet and set the T-bit in the Chunk Flags to indicate that the 3135 * Verification Tag is reflected. After sending this ABORT, the 3136 * receiver of the OOTB packet shall discard the OOTB packet and take 3137 * no further action. 3138 * 3139 * Verification Tag: 3140 * 3141 * The return value is the disposition of the chunk. 3142 */ 3143 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 3144 const struct sctp_association *asoc, 3145 const sctp_subtype_t type, 3146 void *arg, 3147 sctp_cmd_seq_t *commands) 3148 { 3149 struct sctp_packet *packet = NULL; 3150 struct sctp_chunk *chunk = arg; 3151 struct sctp_chunk *abort; 3152 3153 packet = sctp_ootb_pkt_new(asoc, chunk); 3154 3155 if (packet) { 3156 /* Make an ABORT. The T bit will be set if the asoc 3157 * is NULL. 3158 */ 3159 abort = sctp_make_abort(asoc, chunk, 0); 3160 if (!abort) { 3161 sctp_ootb_pkt_free(packet); 3162 return SCTP_DISPOSITION_NOMEM; 3163 } 3164 3165 /* Reflect vtag if T-Bit is set */ 3166 if (sctp_test_T_bit(abort)) 3167 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3168 3169 /* Set the skb to the belonging sock for accounting. */ 3170 abort->skb->sk = ep->base.sk; 3171 3172 sctp_packet_append_chunk(packet, abort); 3173 3174 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3175 SCTP_PACKET(packet)); 3176 3177 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3178 3179 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3180 return SCTP_DISPOSITION_CONSUME; 3181 } 3182 3183 return SCTP_DISPOSITION_NOMEM; 3184 } 3185 3186 /* 3187 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3188 * event as ULP notification for each cause included in the chunk. 3189 * 3190 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3191 * 3192 * The return value is the disposition of the chunk. 3193 */ 3194 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 3195 const struct sctp_association *asoc, 3196 const sctp_subtype_t type, 3197 void *arg, 3198 sctp_cmd_seq_t *commands) 3199 { 3200 struct sctp_chunk *chunk = arg; 3201 3202 if (!sctp_vtag_verify(chunk, asoc)) 3203 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3204 3205 /* Make sure that the ERROR chunk has a valid length. */ 3206 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3207 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3208 commands); 3209 3210 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3211 SCTP_CHUNK(chunk)); 3212 3213 return SCTP_DISPOSITION_CONSUME; 3214 } 3215 3216 /* 3217 * Process an inbound SHUTDOWN ACK. 3218 * 3219 * From Section 9.2: 3220 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3221 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3222 * peer, and remove all record of the association. 3223 * 3224 * The return value is the disposition. 3225 */ 3226 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3227 const struct sctp_association *asoc, 3228 const sctp_subtype_t type, 3229 void *arg, 3230 sctp_cmd_seq_t *commands) 3231 { 3232 struct sctp_chunk *chunk = arg; 3233 struct sctp_chunk *reply; 3234 struct sctp_ulpevent *ev; 3235 3236 if (!sctp_vtag_verify(chunk, asoc)) 3237 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3238 3239 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3240 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3241 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3242 commands); 3243 /* 10.2 H) SHUTDOWN COMPLETE notification 3244 * 3245 * When SCTP completes the shutdown procedures (section 9.2) this 3246 * notification is passed to the upper layer. 3247 */ 3248 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3249 0, 0, 0, NULL, GFP_ATOMIC); 3250 if (!ev) 3251 goto nomem; 3252 3253 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3254 reply = sctp_make_shutdown_complete(asoc, chunk); 3255 if (!reply) 3256 goto nomem_chunk; 3257 3258 /* Do all the commands now (after allocation), so that we 3259 * have consistent state if memory allocation failes 3260 */ 3261 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3262 3263 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3264 * stop the T2-shutdown timer, 3265 */ 3266 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3267 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3268 3269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3270 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3271 3272 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3273 SCTP_STATE(SCTP_STATE_CLOSED)); 3274 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3275 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3276 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3277 3278 /* ...and remove all record of the association. */ 3279 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3280 return SCTP_DISPOSITION_DELETE_TCB; 3281 3282 nomem_chunk: 3283 sctp_ulpevent_free(ev); 3284 nomem: 3285 return SCTP_DISPOSITION_NOMEM; 3286 } 3287 3288 /* 3289 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3290 * 3291 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3292 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3293 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3294 * packet must fill in the Verification Tag field of the outbound 3295 * packet with the Verification Tag received in the SHUTDOWN ACK and 3296 * set the T-bit in the Chunk Flags to indicate that the Verification 3297 * Tag is reflected. 3298 * 3299 * 8) The receiver should respond to the sender of the OOTB packet with 3300 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3301 * MUST fill in the Verification Tag field of the outbound packet 3302 * with the value found in the Verification Tag field of the OOTB 3303 * packet and set the T-bit in the Chunk Flags to indicate that the 3304 * Verification Tag is reflected. After sending this ABORT, the 3305 * receiver of the OOTB packet shall discard the OOTB packet and take 3306 * no further action. 3307 */ 3308 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3309 const struct sctp_association *asoc, 3310 const sctp_subtype_t type, 3311 void *arg, 3312 sctp_cmd_seq_t *commands) 3313 { 3314 struct sctp_chunk *chunk = arg; 3315 struct sk_buff *skb = chunk->skb; 3316 sctp_chunkhdr_t *ch; 3317 __u8 *ch_end; 3318 int ootb_shut_ack = 0; 3319 3320 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3321 3322 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3323 do { 3324 /* Report violation if the chunk is less then minimal */ 3325 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3326 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3327 commands); 3328 3329 /* Now that we know we at least have a chunk header, 3330 * do things that are type appropriate. 3331 */ 3332 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3333 ootb_shut_ack = 1; 3334 3335 /* RFC 2960, Section 3.3.7 3336 * Moreover, under any circumstances, an endpoint that 3337 * receives an ABORT MUST NOT respond to that ABORT by 3338 * sending an ABORT of its own. 3339 */ 3340 if (SCTP_CID_ABORT == ch->type) 3341 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3342 3343 /* Report violation if chunk len overflows */ 3344 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3345 if (ch_end > skb_tail_pointer(skb)) 3346 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3347 commands); 3348 3349 ch = (sctp_chunkhdr_t *) ch_end; 3350 } while (ch_end < skb_tail_pointer(skb)); 3351 3352 if (ootb_shut_ack) 3353 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3354 else 3355 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3356 } 3357 3358 /* 3359 * Handle an "Out of the blue" SHUTDOWN ACK. 3360 * 3361 * Section: 8.4 5, sctpimpguide 2.41. 3362 * 3363 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3364 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3365 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3366 * packet must fill in the Verification Tag field of the outbound 3367 * packet with the Verification Tag received in the SHUTDOWN ACK and 3368 * set the T-bit in the Chunk Flags to indicate that the Verification 3369 * Tag is reflected. 3370 * 3371 * Inputs 3372 * (endpoint, asoc, type, arg, commands) 3373 * 3374 * Outputs 3375 * (sctp_disposition_t) 3376 * 3377 * The return value is the disposition of the chunk. 3378 */ 3379 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3380 const struct sctp_association *asoc, 3381 const sctp_subtype_t type, 3382 void *arg, 3383 sctp_cmd_seq_t *commands) 3384 { 3385 struct sctp_packet *packet = NULL; 3386 struct sctp_chunk *chunk = arg; 3387 struct sctp_chunk *shut; 3388 3389 packet = sctp_ootb_pkt_new(asoc, chunk); 3390 3391 if (packet) { 3392 /* Make an SHUTDOWN_COMPLETE. 3393 * The T bit will be set if the asoc is NULL. 3394 */ 3395 shut = sctp_make_shutdown_complete(asoc, chunk); 3396 if (!shut) { 3397 sctp_ootb_pkt_free(packet); 3398 return SCTP_DISPOSITION_NOMEM; 3399 } 3400 3401 /* Reflect vtag if T-Bit is set */ 3402 if (sctp_test_T_bit(shut)) 3403 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3404 3405 /* Set the skb to the belonging sock for accounting. */ 3406 shut->skb->sk = ep->base.sk; 3407 3408 sctp_packet_append_chunk(packet, shut); 3409 3410 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3411 SCTP_PACKET(packet)); 3412 3413 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3414 3415 /* If the chunk length is invalid, we don't want to process 3416 * the reset of the packet. 3417 */ 3418 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3419 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3420 3421 /* We need to discard the rest of the packet to prevent 3422 * potential bomming attacks from additional bundled chunks. 3423 * This is documented in SCTP Threats ID. 3424 */ 3425 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3426 } 3427 3428 return SCTP_DISPOSITION_NOMEM; 3429 } 3430 3431 /* 3432 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3433 * 3434 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3435 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3436 * procedures in section 8.4 SHOULD be followed, in other words it 3437 * should be treated as an Out Of The Blue packet. 3438 * [This means that we do NOT check the Verification Tag on these 3439 * chunks. --piggy ] 3440 * 3441 */ 3442 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3443 const struct sctp_association *asoc, 3444 const sctp_subtype_t type, 3445 void *arg, 3446 sctp_cmd_seq_t *commands) 3447 { 3448 struct sctp_chunk *chunk = arg; 3449 3450 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3451 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3452 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3453 commands); 3454 3455 /* Although we do have an association in this case, it corresponds 3456 * to a restarted association. So the packet is treated as an OOTB 3457 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3458 * called with a NULL association. 3459 */ 3460 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3461 3462 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3463 } 3464 3465 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3466 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3467 const struct sctp_association *asoc, 3468 const sctp_subtype_t type, void *arg, 3469 sctp_cmd_seq_t *commands) 3470 { 3471 struct sctp_chunk *chunk = arg; 3472 struct sctp_chunk *asconf_ack = NULL; 3473 struct sctp_paramhdr *err_param = NULL; 3474 sctp_addiphdr_t *hdr; 3475 union sctp_addr_param *addr_param; 3476 __u32 serial; 3477 int length; 3478 3479 if (!sctp_vtag_verify(chunk, asoc)) { 3480 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3481 SCTP_NULL()); 3482 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3483 } 3484 3485 /* ADD-IP: Section 4.1.1 3486 * This chunk MUST be sent in an authenticated way by using 3487 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3488 * is received unauthenticated it MUST be silently discarded as 3489 * described in [I-D.ietf-tsvwg-sctp-auth]. 3490 */ 3491 if (!sctp_addip_noauth && !chunk->auth) 3492 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3493 3494 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3495 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3496 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3497 commands); 3498 3499 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3500 serial = ntohl(hdr->serial); 3501 3502 addr_param = (union sctp_addr_param *)hdr->params; 3503 length = ntohs(addr_param->p.length); 3504 if (length < sizeof(sctp_paramhdr_t)) 3505 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3506 (void *)addr_param, commands); 3507 3508 /* Verify the ASCONF chunk before processing it. */ 3509 if (!sctp_verify_asconf(asoc, 3510 (sctp_paramhdr_t *)((void *)addr_param + length), 3511 (void *)chunk->chunk_end, 3512 &err_param)) 3513 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3514 (void *)err_param, commands); 3515 3516 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3517 * the endpoint stored in a new association variable 3518 * 'Peer-Serial-Number'. 3519 */ 3520 if (serial == asoc->peer.addip_serial + 1) { 3521 /* If this is the first instance of ASCONF in the packet, 3522 * we can clean our old ASCONF-ACKs. 3523 */ 3524 if (!chunk->has_asconf) 3525 sctp_assoc_clean_asconf_ack_cache(asoc); 3526 3527 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3528 * expected, process the ASCONF as described below and after 3529 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3530 * the response packet and cache a copy of it (in the event it 3531 * later needs to be retransmitted). 3532 * 3533 * Essentially, do V1-V5. 3534 */ 3535 asconf_ack = sctp_process_asconf((struct sctp_association *) 3536 asoc, chunk); 3537 if (!asconf_ack) 3538 return SCTP_DISPOSITION_NOMEM; 3539 } else if (serial < asoc->peer.addip_serial + 1) { 3540 /* ADDIP 5.2 E2) 3541 * If the value found in the Sequence Number is less than the 3542 * ('Peer- Sequence-Number' + 1), simply skip to the next 3543 * ASCONF, and include in the outbound response packet 3544 * any previously cached ASCONF-ACK response that was 3545 * sent and saved that matches the Sequence Number of the 3546 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3547 * Chunk exists. This will occur when an older ASCONF 3548 * arrives out of order. In such a case, the receiver 3549 * should skip the ASCONF Chunk and not include ASCONF-ACK 3550 * Chunk for that chunk. 3551 */ 3552 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3553 if (!asconf_ack) 3554 return SCTP_DISPOSITION_DISCARD; 3555 3556 /* Reset the transport so that we select the correct one 3557 * this time around. This is to make sure that we don't 3558 * accidentally use a stale transport that's been removed. 3559 */ 3560 asconf_ack->transport = NULL; 3561 } else { 3562 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3563 * it must be either a stale packet or from an attacker. 3564 */ 3565 return SCTP_DISPOSITION_DISCARD; 3566 } 3567 3568 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3569 * containing the ASCONF-ACK Chunks MUST be the source address of 3570 * the SCTP packet that held the ASCONF Chunks. 3571 * 3572 * To do this properly, we'll set the destination address of the chunk 3573 * and at the transmit time, will try look up the transport to use. 3574 * Since ASCONFs may be bundled, the correct transport may not be 3575 * created untill we process the entire packet, thus this workaround. 3576 */ 3577 asconf_ack->dest = chunk->source; 3578 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3579 3580 return SCTP_DISPOSITION_CONSUME; 3581 } 3582 3583 /* 3584 * ADDIP Section 4.3 General rules for address manipulation 3585 * When building TLV parameters for the ASCONF Chunk that will add or 3586 * delete IP addresses the D0 to D13 rules should be applied: 3587 */ 3588 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3589 const struct sctp_association *asoc, 3590 const sctp_subtype_t type, void *arg, 3591 sctp_cmd_seq_t *commands) 3592 { 3593 struct sctp_chunk *asconf_ack = arg; 3594 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3595 struct sctp_chunk *abort; 3596 struct sctp_paramhdr *err_param = NULL; 3597 sctp_addiphdr_t *addip_hdr; 3598 __u32 sent_serial, rcvd_serial; 3599 3600 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3601 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3602 SCTP_NULL()); 3603 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3604 } 3605 3606 /* ADD-IP, Section 4.1.2: 3607 * This chunk MUST be sent in an authenticated way by using 3608 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3609 * is received unauthenticated it MUST be silently discarded as 3610 * described in [I-D.ietf-tsvwg-sctp-auth]. 3611 */ 3612 if (!sctp_addip_noauth && !asconf_ack->auth) 3613 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3614 3615 /* Make sure that the ADDIP chunk has a valid length. */ 3616 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3617 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3618 commands); 3619 3620 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3621 rcvd_serial = ntohl(addip_hdr->serial); 3622 3623 /* Verify the ASCONF-ACK chunk before processing it. */ 3624 if (!sctp_verify_asconf(asoc, 3625 (sctp_paramhdr_t *)addip_hdr->params, 3626 (void *)asconf_ack->chunk_end, 3627 &err_param)) 3628 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3629 (void *)err_param, commands); 3630 3631 if (last_asconf) { 3632 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3633 sent_serial = ntohl(addip_hdr->serial); 3634 } else { 3635 sent_serial = asoc->addip_serial - 1; 3636 } 3637 3638 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3639 * equal to the next serial number to be used but no ASCONF chunk is 3640 * outstanding the endpoint MUST ABORT the association. Note that a 3641 * sequence number is greater than if it is no more than 2^^31-1 3642 * larger than the current sequence number (using serial arithmetic). 3643 */ 3644 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3645 !(asoc->addip_last_asconf)) { 3646 abort = sctp_make_abort(asoc, asconf_ack, 3647 sizeof(sctp_errhdr_t)); 3648 if (abort) { 3649 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3650 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3651 SCTP_CHUNK(abort)); 3652 } 3653 /* We are going to ABORT, so we might as well stop 3654 * processing the rest of the chunks in the packet. 3655 */ 3656 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3657 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3658 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3659 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3660 SCTP_ERROR(ECONNABORTED)); 3661 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3662 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3663 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3664 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3665 return SCTP_DISPOSITION_ABORT; 3666 } 3667 3668 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3669 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3670 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3671 3672 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3673 asconf_ack)) 3674 return SCTP_DISPOSITION_CONSUME; 3675 3676 abort = sctp_make_abort(asoc, asconf_ack, 3677 sizeof(sctp_errhdr_t)); 3678 if (abort) { 3679 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3680 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3681 SCTP_CHUNK(abort)); 3682 } 3683 /* We are going to ABORT, so we might as well stop 3684 * processing the rest of the chunks in the packet. 3685 */ 3686 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3687 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3688 SCTP_ERROR(ECONNABORTED)); 3689 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3690 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3691 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3692 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3693 return SCTP_DISPOSITION_ABORT; 3694 } 3695 3696 return SCTP_DISPOSITION_DISCARD; 3697 } 3698 3699 /* 3700 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3701 * 3702 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3703 * its cumulative TSN point to the value carried in the FORWARD TSN 3704 * chunk, and then MUST further advance its cumulative TSN point locally 3705 * if possible. 3706 * After the above processing, the data receiver MUST stop reporting any 3707 * missing TSNs earlier than or equal to the new cumulative TSN point. 3708 * 3709 * Verification Tag: 8.5 Verification Tag [Normal verification] 3710 * 3711 * The return value is the disposition of the chunk. 3712 */ 3713 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3714 const struct sctp_association *asoc, 3715 const sctp_subtype_t type, 3716 void *arg, 3717 sctp_cmd_seq_t *commands) 3718 { 3719 struct sctp_chunk *chunk = arg; 3720 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3721 struct sctp_fwdtsn_skip *skip; 3722 __u16 len; 3723 __u32 tsn; 3724 3725 if (!sctp_vtag_verify(chunk, asoc)) { 3726 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3727 SCTP_NULL()); 3728 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3729 } 3730 3731 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3732 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3733 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3734 commands); 3735 3736 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3737 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3738 len = ntohs(chunk->chunk_hdr->length); 3739 len -= sizeof(struct sctp_chunkhdr); 3740 skb_pull(chunk->skb, len); 3741 3742 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3743 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3744 3745 /* The TSN is too high--silently discard the chunk and count on it 3746 * getting retransmitted later. 3747 */ 3748 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3749 goto discard_noforce; 3750 3751 /* Silently discard the chunk if stream-id is not valid */ 3752 sctp_walk_fwdtsn(skip, chunk) { 3753 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3754 goto discard_noforce; 3755 } 3756 3757 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3758 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3759 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3760 SCTP_CHUNK(chunk)); 3761 3762 /* Count this as receiving DATA. */ 3763 if (asoc->autoclose) { 3764 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3765 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3766 } 3767 3768 /* FIXME: For now send a SACK, but DATA processing may 3769 * send another. 3770 */ 3771 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3772 3773 return SCTP_DISPOSITION_CONSUME; 3774 3775 discard_noforce: 3776 return SCTP_DISPOSITION_DISCARD; 3777 } 3778 3779 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3780 const struct sctp_endpoint *ep, 3781 const struct sctp_association *asoc, 3782 const sctp_subtype_t type, 3783 void *arg, 3784 sctp_cmd_seq_t *commands) 3785 { 3786 struct sctp_chunk *chunk = arg; 3787 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3788 struct sctp_fwdtsn_skip *skip; 3789 __u16 len; 3790 __u32 tsn; 3791 3792 if (!sctp_vtag_verify(chunk, asoc)) { 3793 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3794 SCTP_NULL()); 3795 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3796 } 3797 3798 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3799 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3800 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3801 commands); 3802 3803 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3804 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3805 len = ntohs(chunk->chunk_hdr->length); 3806 len -= sizeof(struct sctp_chunkhdr); 3807 skb_pull(chunk->skb, len); 3808 3809 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3810 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3811 3812 /* The TSN is too high--silently discard the chunk and count on it 3813 * getting retransmitted later. 3814 */ 3815 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3816 goto gen_shutdown; 3817 3818 /* Silently discard the chunk if stream-id is not valid */ 3819 sctp_walk_fwdtsn(skip, chunk) { 3820 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3821 goto gen_shutdown; 3822 } 3823 3824 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3825 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3826 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3827 SCTP_CHUNK(chunk)); 3828 3829 /* Go a head and force a SACK, since we are shutting down. */ 3830 gen_shutdown: 3831 /* Implementor's Guide. 3832 * 3833 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3834 * respond to each received packet containing one or more DATA chunk(s) 3835 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3836 */ 3837 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3838 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3839 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3840 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3841 3842 return SCTP_DISPOSITION_CONSUME; 3843 } 3844 3845 /* 3846 * SCTP-AUTH Section 6.3 Receving authenticated chukns 3847 * 3848 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3849 * Identifier field. If this algorithm was not specified by the 3850 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3851 * during association setup, the AUTH chunk and all chunks after it MUST 3852 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3853 * defined in Section 4.1. 3854 * 3855 * If an endpoint with no shared key receives a Shared Key Identifier 3856 * other than 0, it MUST silently discard all authenticated chunks. If 3857 * the endpoint has at least one endpoint pair shared key for the peer, 3858 * it MUST use the key specified by the Shared Key Identifier if a 3859 * key has been configured for that Shared Key Identifier. If no 3860 * endpoint pair shared key has been configured for that Shared Key 3861 * Identifier, all authenticated chunks MUST be silently discarded. 3862 * 3863 * Verification Tag: 8.5 Verification Tag [Normal verification] 3864 * 3865 * The return value is the disposition of the chunk. 3866 */ 3867 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 3868 const struct sctp_association *asoc, 3869 const sctp_subtype_t type, 3870 struct sctp_chunk *chunk) 3871 { 3872 struct sctp_authhdr *auth_hdr; 3873 struct sctp_hmac *hmac; 3874 unsigned int sig_len; 3875 __u16 key_id; 3876 __u8 *save_digest; 3877 __u8 *digest; 3878 3879 /* Pull in the auth header, so we can do some more verification */ 3880 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3881 chunk->subh.auth_hdr = auth_hdr; 3882 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3883 3884 /* Make sure that we suport the HMAC algorithm from the auth 3885 * chunk. 3886 */ 3887 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 3888 return SCTP_IERROR_AUTH_BAD_HMAC; 3889 3890 /* Make sure that the provided shared key identifier has been 3891 * configured 3892 */ 3893 key_id = ntohs(auth_hdr->shkey_id); 3894 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 3895 return SCTP_IERROR_AUTH_BAD_KEYID; 3896 3897 3898 /* Make sure that the length of the signature matches what 3899 * we expect. 3900 */ 3901 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 3902 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 3903 if (sig_len != hmac->hmac_len) 3904 return SCTP_IERROR_PROTO_VIOLATION; 3905 3906 /* Now that we've done validation checks, we can compute and 3907 * verify the hmac. The steps involved are: 3908 * 1. Save the digest from the chunk. 3909 * 2. Zero out the digest in the chunk. 3910 * 3. Compute the new digest 3911 * 4. Compare saved and new digests. 3912 */ 3913 digest = auth_hdr->hmac; 3914 skb_pull(chunk->skb, sig_len); 3915 3916 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 3917 if (!save_digest) 3918 goto nomem; 3919 3920 memset(digest, 0, sig_len); 3921 3922 sctp_auth_calculate_hmac(asoc, chunk->skb, 3923 (struct sctp_auth_chunk *)chunk->chunk_hdr, 3924 GFP_ATOMIC); 3925 3926 /* Discard the packet if the digests do not match */ 3927 if (memcmp(save_digest, digest, sig_len)) { 3928 kfree(save_digest); 3929 return SCTP_IERROR_BAD_SIG; 3930 } 3931 3932 kfree(save_digest); 3933 chunk->auth = 1; 3934 3935 return SCTP_IERROR_NO_ERROR; 3936 nomem: 3937 return SCTP_IERROR_NOMEM; 3938 } 3939 3940 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep, 3941 const struct sctp_association *asoc, 3942 const sctp_subtype_t type, 3943 void *arg, 3944 sctp_cmd_seq_t *commands) 3945 { 3946 struct sctp_authhdr *auth_hdr; 3947 struct sctp_chunk *chunk = arg; 3948 struct sctp_chunk *err_chunk; 3949 sctp_ierror_t error; 3950 3951 /* Make sure that the peer has AUTH capable */ 3952 if (!asoc->peer.auth_capable) 3953 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands); 3954 3955 if (!sctp_vtag_verify(chunk, asoc)) { 3956 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3957 SCTP_NULL()); 3958 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3959 } 3960 3961 /* Make sure that the AUTH chunk has valid length. */ 3962 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 3963 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3964 commands); 3965 3966 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3967 error = sctp_sf_authenticate(ep, asoc, type, chunk); 3968 switch (error) { 3969 case SCTP_IERROR_AUTH_BAD_HMAC: 3970 /* Generate the ERROR chunk and discard the rest 3971 * of the packet 3972 */ 3973 err_chunk = sctp_make_op_error(asoc, chunk, 3974 SCTP_ERROR_UNSUP_HMAC, 3975 &auth_hdr->hmac_id, 3976 sizeof(__u16)); 3977 if (err_chunk) { 3978 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3979 SCTP_CHUNK(err_chunk)); 3980 } 3981 /* Fall Through */ 3982 case SCTP_IERROR_AUTH_BAD_KEYID: 3983 case SCTP_IERROR_BAD_SIG: 3984 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3985 break; 3986 case SCTP_IERROR_PROTO_VIOLATION: 3987 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3988 commands); 3989 break; 3990 case SCTP_IERROR_NOMEM: 3991 return SCTP_DISPOSITION_NOMEM; 3992 default: 3993 break; 3994 } 3995 3996 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 3997 struct sctp_ulpevent *ev; 3998 3999 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4000 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4001 4002 if (!ev) 4003 return -ENOMEM; 4004 4005 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4006 SCTP_ULPEVENT(ev)); 4007 } 4008 4009 return SCTP_DISPOSITION_CONSUME; 4010 } 4011 4012 /* 4013 * Process an unknown chunk. 4014 * 4015 * Section: 3.2. Also, 2.1 in the implementor's guide. 4016 * 4017 * Chunk Types are encoded such that the highest-order two bits specify 4018 * the action that must be taken if the processing endpoint does not 4019 * recognize the Chunk Type. 4020 * 4021 * 00 - Stop processing this SCTP packet and discard it, do not process 4022 * any further chunks within it. 4023 * 4024 * 01 - Stop processing this SCTP packet and discard it, do not process 4025 * any further chunks within it, and report the unrecognized 4026 * chunk in an 'Unrecognized Chunk Type'. 4027 * 4028 * 10 - Skip this chunk and continue processing. 4029 * 4030 * 11 - Skip this chunk and continue processing, but report in an ERROR 4031 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4032 * 4033 * The return value is the disposition of the chunk. 4034 */ 4035 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 4036 const struct sctp_association *asoc, 4037 const sctp_subtype_t type, 4038 void *arg, 4039 sctp_cmd_seq_t *commands) 4040 { 4041 struct sctp_chunk *unk_chunk = arg; 4042 struct sctp_chunk *err_chunk; 4043 sctp_chunkhdr_t *hdr; 4044 4045 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 4046 4047 if (!sctp_vtag_verify(unk_chunk, asoc)) 4048 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4049 4050 /* Make sure that the chunk has a valid length. 4051 * Since we don't know the chunk type, we use a general 4052 * chunkhdr structure to make a comparison. 4053 */ 4054 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4055 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4056 commands); 4057 4058 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4059 case SCTP_CID_ACTION_DISCARD: 4060 /* Discard the packet. */ 4061 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4062 break; 4063 case SCTP_CID_ACTION_DISCARD_ERR: 4064 /* Generate an ERROR chunk as response. */ 4065 hdr = unk_chunk->chunk_hdr; 4066 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4067 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4068 WORD_ROUND(ntohs(hdr->length))); 4069 if (err_chunk) { 4070 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4071 SCTP_CHUNK(err_chunk)); 4072 } 4073 4074 /* Discard the packet. */ 4075 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4076 return SCTP_DISPOSITION_CONSUME; 4077 break; 4078 case SCTP_CID_ACTION_SKIP: 4079 /* Skip the chunk. */ 4080 return SCTP_DISPOSITION_DISCARD; 4081 break; 4082 case SCTP_CID_ACTION_SKIP_ERR: 4083 /* Generate an ERROR chunk as response. */ 4084 hdr = unk_chunk->chunk_hdr; 4085 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4086 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4087 WORD_ROUND(ntohs(hdr->length))); 4088 if (err_chunk) { 4089 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4090 SCTP_CHUNK(err_chunk)); 4091 } 4092 /* Skip the chunk. */ 4093 return SCTP_DISPOSITION_CONSUME; 4094 break; 4095 default: 4096 break; 4097 } 4098 4099 return SCTP_DISPOSITION_DISCARD; 4100 } 4101 4102 /* 4103 * Discard the chunk. 4104 * 4105 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4106 * [Too numerous to mention...] 4107 * Verification Tag: No verification needed. 4108 * Inputs 4109 * (endpoint, asoc, chunk) 4110 * 4111 * Outputs 4112 * (asoc, reply_msg, msg_up, timers, counters) 4113 * 4114 * The return value is the disposition of the chunk. 4115 */ 4116 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 4117 const struct sctp_association *asoc, 4118 const sctp_subtype_t type, 4119 void *arg, 4120 sctp_cmd_seq_t *commands) 4121 { 4122 struct sctp_chunk *chunk = arg; 4123 4124 /* Make sure that the chunk has a valid length. 4125 * Since we don't know the chunk type, we use a general 4126 * chunkhdr structure to make a comparison. 4127 */ 4128 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4129 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4130 commands); 4131 4132 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 4133 return SCTP_DISPOSITION_DISCARD; 4134 } 4135 4136 /* 4137 * Discard the whole packet. 4138 * 4139 * Section: 8.4 2) 4140 * 4141 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4142 * silently discard the OOTB packet and take no further action. 4143 * 4144 * Verification Tag: No verification necessary 4145 * 4146 * Inputs 4147 * (endpoint, asoc, chunk) 4148 * 4149 * Outputs 4150 * (asoc, reply_msg, msg_up, timers, counters) 4151 * 4152 * The return value is the disposition of the chunk. 4153 */ 4154 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 4155 const struct sctp_association *asoc, 4156 const sctp_subtype_t type, 4157 void *arg, 4158 sctp_cmd_seq_t *commands) 4159 { 4160 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS); 4161 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4162 4163 return SCTP_DISPOSITION_CONSUME; 4164 } 4165 4166 4167 /* 4168 * The other end is violating protocol. 4169 * 4170 * Section: Not specified 4171 * Verification Tag: Not specified 4172 * Inputs 4173 * (endpoint, asoc, chunk) 4174 * 4175 * Outputs 4176 * (asoc, reply_msg, msg_up, timers, counters) 4177 * 4178 * We simply tag the chunk as a violation. The state machine will log 4179 * the violation and continue. 4180 */ 4181 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 4182 const struct sctp_association *asoc, 4183 const sctp_subtype_t type, 4184 void *arg, 4185 sctp_cmd_seq_t *commands) 4186 { 4187 struct sctp_chunk *chunk = arg; 4188 4189 /* Make sure that the chunk has a valid length. */ 4190 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4191 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4192 commands); 4193 4194 return SCTP_DISPOSITION_VIOLATION; 4195 } 4196 4197 /* 4198 * Common function to handle a protocol violation. 4199 */ 4200 static sctp_disposition_t sctp_sf_abort_violation( 4201 const struct sctp_endpoint *ep, 4202 const struct sctp_association *asoc, 4203 void *arg, 4204 sctp_cmd_seq_t *commands, 4205 const __u8 *payload, 4206 const size_t paylen) 4207 { 4208 struct sctp_packet *packet = NULL; 4209 struct sctp_chunk *chunk = arg; 4210 struct sctp_chunk *abort = NULL; 4211 4212 /* SCTP-AUTH, Section 6.3: 4213 * It should be noted that if the receiver wants to tear 4214 * down an association in an authenticated way only, the 4215 * handling of malformed packets should not result in 4216 * tearing down the association. 4217 * 4218 * This means that if we only want to abort associations 4219 * in an authenticated way (i.e AUTH+ABORT), then we 4220 * can't destroy this association just becuase the packet 4221 * was malformed. 4222 */ 4223 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4224 goto discard; 4225 4226 /* Make the abort chunk. */ 4227 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4228 if (!abort) 4229 goto nomem; 4230 4231 if (asoc) { 4232 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4233 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4234 !asoc->peer.i.init_tag) { 4235 sctp_initack_chunk_t *initack; 4236 4237 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4238 if (!sctp_chunk_length_valid(chunk, 4239 sizeof(sctp_initack_chunk_t))) 4240 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4241 else { 4242 unsigned int inittag; 4243 4244 inittag = ntohl(initack->init_hdr.init_tag); 4245 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4246 SCTP_U32(inittag)); 4247 } 4248 } 4249 4250 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4251 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4252 4253 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4254 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4255 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4256 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4257 SCTP_ERROR(ECONNREFUSED)); 4258 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4259 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4260 } else { 4261 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4262 SCTP_ERROR(ECONNABORTED)); 4263 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4264 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4265 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4266 } 4267 } else { 4268 packet = sctp_ootb_pkt_new(asoc, chunk); 4269 4270 if (!packet) 4271 goto nomem_pkt; 4272 4273 if (sctp_test_T_bit(abort)) 4274 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4275 4276 abort->skb->sk = ep->base.sk; 4277 4278 sctp_packet_append_chunk(packet, abort); 4279 4280 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4281 SCTP_PACKET(packet)); 4282 4283 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4284 } 4285 4286 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4287 4288 discard: 4289 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4290 return SCTP_DISPOSITION_ABORT; 4291 4292 nomem_pkt: 4293 sctp_chunk_free(abort); 4294 nomem: 4295 return SCTP_DISPOSITION_NOMEM; 4296 } 4297 4298 /* 4299 * Handle a protocol violation when the chunk length is invalid. 4300 * "Invalid" length is identified as smaller than the minimal length a 4301 * given chunk can be. For example, a SACK chunk has invalid length 4302 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4303 * 4304 * We inform the other end by sending an ABORT with a Protocol Violation 4305 * error code. 4306 * 4307 * Section: Not specified 4308 * Verification Tag: Nothing to do 4309 * Inputs 4310 * (endpoint, asoc, chunk) 4311 * 4312 * Outputs 4313 * (reply_msg, msg_up, counters) 4314 * 4315 * Generate an ABORT chunk and terminate the association. 4316 */ 4317 static sctp_disposition_t sctp_sf_violation_chunklen( 4318 const struct sctp_endpoint *ep, 4319 const struct sctp_association *asoc, 4320 const sctp_subtype_t type, 4321 void *arg, 4322 sctp_cmd_seq_t *commands) 4323 { 4324 static const char err_str[]="The following chunk had invalid length:"; 4325 4326 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4327 sizeof(err_str)); 4328 } 4329 4330 /* 4331 * Handle a protocol violation when the parameter length is invalid. 4332 * "Invalid" length is identified as smaller than the minimal length a 4333 * given parameter can be. 4334 */ 4335 static sctp_disposition_t sctp_sf_violation_paramlen( 4336 const struct sctp_endpoint *ep, 4337 const struct sctp_association *asoc, 4338 const sctp_subtype_t type, 4339 void *arg, void *ext, 4340 sctp_cmd_seq_t *commands) 4341 { 4342 struct sctp_chunk *chunk = arg; 4343 struct sctp_paramhdr *param = ext; 4344 struct sctp_chunk *abort = NULL; 4345 4346 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4347 goto discard; 4348 4349 /* Make the abort chunk. */ 4350 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4351 if (!abort) 4352 goto nomem; 4353 4354 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4355 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4356 4357 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4358 SCTP_ERROR(ECONNABORTED)); 4359 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4360 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4361 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4362 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4363 4364 discard: 4365 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4366 return SCTP_DISPOSITION_ABORT; 4367 nomem: 4368 return SCTP_DISPOSITION_NOMEM; 4369 } 4370 4371 /* Handle a protocol violation when the peer trying to advance the 4372 * cumulative tsn ack to a point beyond the max tsn currently sent. 4373 * 4374 * We inform the other end by sending an ABORT with a Protocol Violation 4375 * error code. 4376 */ 4377 static sctp_disposition_t sctp_sf_violation_ctsn( 4378 const struct sctp_endpoint *ep, 4379 const struct sctp_association *asoc, 4380 const sctp_subtype_t type, 4381 void *arg, 4382 sctp_cmd_seq_t *commands) 4383 { 4384 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4385 4386 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4387 sizeof(err_str)); 4388 } 4389 4390 /* Handle protocol violation of an invalid chunk bundling. For example, 4391 * when we have an association and we recieve bundled INIT-ACK, or 4392 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4393 * statement from the specs. Additinally, there might be an attacker 4394 * on the path and we may not want to continue this communication. 4395 */ 4396 static sctp_disposition_t sctp_sf_violation_chunk( 4397 const struct sctp_endpoint *ep, 4398 const struct sctp_association *asoc, 4399 const sctp_subtype_t type, 4400 void *arg, 4401 sctp_cmd_seq_t *commands) 4402 { 4403 static const char err_str[]="The following chunk violates protocol:"; 4404 4405 if (!asoc) 4406 return sctp_sf_violation(ep, asoc, type, arg, commands); 4407 4408 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4409 sizeof(err_str)); 4410 } 4411 /*************************************************************************** 4412 * These are the state functions for handling primitive (Section 10) events. 4413 ***************************************************************************/ 4414 /* 4415 * sctp_sf_do_prm_asoc 4416 * 4417 * Section: 10.1 ULP-to-SCTP 4418 * B) Associate 4419 * 4420 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4421 * outbound stream count) 4422 * -> association id [,destination transport addr list] [,outbound stream 4423 * count] 4424 * 4425 * This primitive allows the upper layer to initiate an association to a 4426 * specific peer endpoint. 4427 * 4428 * The peer endpoint shall be specified by one of the transport addresses 4429 * which defines the endpoint (see Section 1.4). If the local SCTP 4430 * instance has not been initialized, the ASSOCIATE is considered an 4431 * error. 4432 * [This is not relevant for the kernel implementation since we do all 4433 * initialization at boot time. It we hadn't initialized we wouldn't 4434 * get anywhere near this code.] 4435 * 4436 * An association id, which is a local handle to the SCTP association, 4437 * will be returned on successful establishment of the association. If 4438 * SCTP is not able to open an SCTP association with the peer endpoint, 4439 * an error is returned. 4440 * [In the kernel implementation, the struct sctp_association needs to 4441 * be created BEFORE causing this primitive to run.] 4442 * 4443 * Other association parameters may be returned, including the 4444 * complete destination transport addresses of the peer as well as the 4445 * outbound stream count of the local endpoint. One of the transport 4446 * address from the returned destination addresses will be selected by 4447 * the local endpoint as default primary path for sending SCTP packets 4448 * to this peer. The returned "destination transport addr list" can 4449 * be used by the ULP to change the default primary path or to force 4450 * sending a packet to a specific transport address. [All of this 4451 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4452 * function.] 4453 * 4454 * Mandatory attributes: 4455 * 4456 * o local SCTP instance name - obtained from the INITIALIZE operation. 4457 * [This is the argument asoc.] 4458 * o destination transport addr - specified as one of the transport 4459 * addresses of the peer endpoint with which the association is to be 4460 * established. 4461 * [This is asoc->peer.active_path.] 4462 * o outbound stream count - the number of outbound streams the ULP 4463 * would like to open towards this peer endpoint. 4464 * [BUG: This is not currently implemented.] 4465 * Optional attributes: 4466 * 4467 * None. 4468 * 4469 * The return value is a disposition. 4470 */ 4471 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 4472 const struct sctp_association *asoc, 4473 const sctp_subtype_t type, 4474 void *arg, 4475 sctp_cmd_seq_t *commands) 4476 { 4477 struct sctp_chunk *repl; 4478 struct sctp_association* my_asoc; 4479 4480 /* The comment below says that we enter COOKIE-WAIT AFTER 4481 * sending the INIT, but that doesn't actually work in our 4482 * implementation... 4483 */ 4484 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4485 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4486 4487 /* RFC 2960 5.1 Normal Establishment of an Association 4488 * 4489 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4490 * must provide its Verification Tag (Tag_A) in the Initiate 4491 * Tag field. Tag_A SHOULD be a random number in the range of 4492 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4493 */ 4494 4495 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4496 if (!repl) 4497 goto nomem; 4498 4499 /* Cast away the const modifier, as we want to just 4500 * rerun it through as a sideffect. 4501 */ 4502 my_asoc = (struct sctp_association *)asoc; 4503 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4504 4505 /* Choose transport for INIT. */ 4506 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4507 SCTP_CHUNK(repl)); 4508 4509 /* After sending the INIT, "A" starts the T1-init timer and 4510 * enters the COOKIE-WAIT state. 4511 */ 4512 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4513 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4514 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4515 return SCTP_DISPOSITION_CONSUME; 4516 4517 nomem: 4518 return SCTP_DISPOSITION_NOMEM; 4519 } 4520 4521 /* 4522 * Process the SEND primitive. 4523 * 4524 * Section: 10.1 ULP-to-SCTP 4525 * E) Send 4526 * 4527 * Format: SEND(association id, buffer address, byte count [,context] 4528 * [,stream id] [,life time] [,destination transport address] 4529 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4530 * -> result 4531 * 4532 * This is the main method to send user data via SCTP. 4533 * 4534 * Mandatory attributes: 4535 * 4536 * o association id - local handle to the SCTP association 4537 * 4538 * o buffer address - the location where the user message to be 4539 * transmitted is stored; 4540 * 4541 * o byte count - The size of the user data in number of bytes; 4542 * 4543 * Optional attributes: 4544 * 4545 * o context - an optional 32 bit integer that will be carried in the 4546 * sending failure notification to the ULP if the transportation of 4547 * this User Message fails. 4548 * 4549 * o stream id - to indicate which stream to send the data on. If not 4550 * specified, stream 0 will be used. 4551 * 4552 * o life time - specifies the life time of the user data. The user data 4553 * will not be sent by SCTP after the life time expires. This 4554 * parameter can be used to avoid efforts to transmit stale 4555 * user messages. SCTP notifies the ULP if the data cannot be 4556 * initiated to transport (i.e. sent to the destination via SCTP's 4557 * send primitive) within the life time variable. However, the 4558 * user data will be transmitted if SCTP has attempted to transmit a 4559 * chunk before the life time expired. 4560 * 4561 * o destination transport address - specified as one of the destination 4562 * transport addresses of the peer endpoint to which this packet 4563 * should be sent. Whenever possible, SCTP should use this destination 4564 * transport address for sending the packets, instead of the current 4565 * primary path. 4566 * 4567 * o unorder flag - this flag, if present, indicates that the user 4568 * would like the data delivered in an unordered fashion to the peer 4569 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4570 * message). 4571 * 4572 * o no-bundle flag - instructs SCTP not to bundle this user data with 4573 * other outbound DATA chunks. SCTP MAY still bundle even when 4574 * this flag is present, when faced with network congestion. 4575 * 4576 * o payload protocol-id - A 32 bit unsigned integer that is to be 4577 * passed to the peer indicating the type of payload protocol data 4578 * being transmitted. This value is passed as opaque data by SCTP. 4579 * 4580 * The return value is the disposition. 4581 */ 4582 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 4583 const struct sctp_association *asoc, 4584 const sctp_subtype_t type, 4585 void *arg, 4586 sctp_cmd_seq_t *commands) 4587 { 4588 struct sctp_datamsg *msg = arg; 4589 4590 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4591 return SCTP_DISPOSITION_CONSUME; 4592 } 4593 4594 /* 4595 * Process the SHUTDOWN primitive. 4596 * 4597 * Section: 10.1: 4598 * C) Shutdown 4599 * 4600 * Format: SHUTDOWN(association id) 4601 * -> result 4602 * 4603 * Gracefully closes an association. Any locally queued user data 4604 * will be delivered to the peer. The association will be terminated only 4605 * after the peer acknowledges all the SCTP packets sent. A success code 4606 * will be returned on successful termination of the association. If 4607 * attempting to terminate the association results in a failure, an error 4608 * code shall be returned. 4609 * 4610 * Mandatory attributes: 4611 * 4612 * o association id - local handle to the SCTP association 4613 * 4614 * Optional attributes: 4615 * 4616 * None. 4617 * 4618 * The return value is the disposition. 4619 */ 4620 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4621 const struct sctp_endpoint *ep, 4622 const struct sctp_association *asoc, 4623 const sctp_subtype_t type, 4624 void *arg, 4625 sctp_cmd_seq_t *commands) 4626 { 4627 int disposition; 4628 4629 /* From 9.2 Shutdown of an Association 4630 * Upon receipt of the SHUTDOWN primitive from its upper 4631 * layer, the endpoint enters SHUTDOWN-PENDING state and 4632 * remains there until all outstanding data has been 4633 * acknowledged by its peer. The endpoint accepts no new data 4634 * from its upper layer, but retransmits data to the far end 4635 * if necessary to fill gaps. 4636 */ 4637 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4638 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4639 4640 disposition = SCTP_DISPOSITION_CONSUME; 4641 if (sctp_outq_is_empty(&asoc->outqueue)) { 4642 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4643 arg, commands); 4644 } 4645 return disposition; 4646 } 4647 4648 /* 4649 * Process the ABORT primitive. 4650 * 4651 * Section: 10.1: 4652 * C) Abort 4653 * 4654 * Format: Abort(association id [, cause code]) 4655 * -> result 4656 * 4657 * Ungracefully closes an association. Any locally queued user data 4658 * will be discarded and an ABORT chunk is sent to the peer. A success code 4659 * will be returned on successful abortion of the association. If 4660 * attempting to abort the association results in a failure, an error 4661 * code shall be returned. 4662 * 4663 * Mandatory attributes: 4664 * 4665 * o association id - local handle to the SCTP association 4666 * 4667 * Optional attributes: 4668 * 4669 * o cause code - reason of the abort to be passed to the peer 4670 * 4671 * None. 4672 * 4673 * The return value is the disposition. 4674 */ 4675 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4676 const struct sctp_endpoint *ep, 4677 const struct sctp_association *asoc, 4678 const sctp_subtype_t type, 4679 void *arg, 4680 sctp_cmd_seq_t *commands) 4681 { 4682 /* From 9.1 Abort of an Association 4683 * Upon receipt of the ABORT primitive from its upper 4684 * layer, the endpoint enters CLOSED state and 4685 * discard all outstanding data has been 4686 * acknowledged by its peer. The endpoint accepts no new data 4687 * from its upper layer, but retransmits data to the far end 4688 * if necessary to fill gaps. 4689 */ 4690 struct sctp_chunk *abort = arg; 4691 sctp_disposition_t retval; 4692 4693 retval = SCTP_DISPOSITION_CONSUME; 4694 4695 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4696 4697 /* Even if we can't send the ABORT due to low memory delete the 4698 * TCB. This is a departure from our typical NOMEM handling. 4699 */ 4700 4701 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4702 SCTP_ERROR(ECONNABORTED)); 4703 /* Delete the established association. */ 4704 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4705 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4706 4707 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4708 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4709 4710 return retval; 4711 } 4712 4713 /* We tried an illegal operation on an association which is closed. */ 4714 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4715 const struct sctp_association *asoc, 4716 const sctp_subtype_t type, 4717 void *arg, 4718 sctp_cmd_seq_t *commands) 4719 { 4720 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4721 return SCTP_DISPOSITION_CONSUME; 4722 } 4723 4724 /* We tried an illegal operation on an association which is shutting 4725 * down. 4726 */ 4727 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4728 const struct sctp_association *asoc, 4729 const sctp_subtype_t type, 4730 void *arg, 4731 sctp_cmd_seq_t *commands) 4732 { 4733 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4734 SCTP_ERROR(-ESHUTDOWN)); 4735 return SCTP_DISPOSITION_CONSUME; 4736 } 4737 4738 /* 4739 * sctp_cookie_wait_prm_shutdown 4740 * 4741 * Section: 4 Note: 2 4742 * Verification Tag: 4743 * Inputs 4744 * (endpoint, asoc) 4745 * 4746 * The RFC does not explicitly address this issue, but is the route through the 4747 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4748 * 4749 * Outputs 4750 * (timers) 4751 */ 4752 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4753 const struct sctp_endpoint *ep, 4754 const struct sctp_association *asoc, 4755 const sctp_subtype_t type, 4756 void *arg, 4757 sctp_cmd_seq_t *commands) 4758 { 4759 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4760 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4761 4762 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4763 SCTP_STATE(SCTP_STATE_CLOSED)); 4764 4765 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4766 4767 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4768 4769 return SCTP_DISPOSITION_DELETE_TCB; 4770 } 4771 4772 /* 4773 * sctp_cookie_echoed_prm_shutdown 4774 * 4775 * Section: 4 Note: 2 4776 * Verification Tag: 4777 * Inputs 4778 * (endpoint, asoc) 4779 * 4780 * The RFC does not explcitly address this issue, but is the route through the 4781 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4782 * 4783 * Outputs 4784 * (timers) 4785 */ 4786 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4787 const struct sctp_endpoint *ep, 4788 const struct sctp_association *asoc, 4789 const sctp_subtype_t type, 4790 void *arg, sctp_cmd_seq_t *commands) 4791 { 4792 /* There is a single T1 timer, so we should be able to use 4793 * common function with the COOKIE-WAIT state. 4794 */ 4795 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4796 } 4797 4798 /* 4799 * sctp_sf_cookie_wait_prm_abort 4800 * 4801 * Section: 4 Note: 2 4802 * Verification Tag: 4803 * Inputs 4804 * (endpoint, asoc) 4805 * 4806 * The RFC does not explicitly address this issue, but is the route through the 4807 * state table when someone issues an abort while in COOKIE_WAIT state. 4808 * 4809 * Outputs 4810 * (timers) 4811 */ 4812 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4813 const struct sctp_endpoint *ep, 4814 const struct sctp_association *asoc, 4815 const sctp_subtype_t type, 4816 void *arg, 4817 sctp_cmd_seq_t *commands) 4818 { 4819 struct sctp_chunk *abort = arg; 4820 sctp_disposition_t retval; 4821 4822 /* Stop T1-init timer */ 4823 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4824 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4825 retval = SCTP_DISPOSITION_CONSUME; 4826 4827 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4828 4829 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4830 SCTP_STATE(SCTP_STATE_CLOSED)); 4831 4832 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4833 4834 /* Even if we can't send the ABORT due to low memory delete the 4835 * TCB. This is a departure from our typical NOMEM handling. 4836 */ 4837 4838 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4839 SCTP_ERROR(ECONNREFUSED)); 4840 /* Delete the established association. */ 4841 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4842 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4843 4844 return retval; 4845 } 4846 4847 /* 4848 * sctp_sf_cookie_echoed_prm_abort 4849 * 4850 * Section: 4 Note: 3 4851 * Verification Tag: 4852 * Inputs 4853 * (endpoint, asoc) 4854 * 4855 * The RFC does not explcitly address this issue, but is the route through the 4856 * state table when someone issues an abort while in COOKIE_ECHOED state. 4857 * 4858 * Outputs 4859 * (timers) 4860 */ 4861 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4862 const struct sctp_endpoint *ep, 4863 const struct sctp_association *asoc, 4864 const sctp_subtype_t type, 4865 void *arg, 4866 sctp_cmd_seq_t *commands) 4867 { 4868 /* There is a single T1 timer, so we should be able to use 4869 * common function with the COOKIE-WAIT state. 4870 */ 4871 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4872 } 4873 4874 /* 4875 * sctp_sf_shutdown_pending_prm_abort 4876 * 4877 * Inputs 4878 * (endpoint, asoc) 4879 * 4880 * The RFC does not explicitly address this issue, but is the route through the 4881 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4882 * 4883 * Outputs 4884 * (timers) 4885 */ 4886 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4887 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 /* Stop the T5-shutdown guard timer. */ 4894 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4895 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4896 4897 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4898 } 4899 4900 /* 4901 * sctp_sf_shutdown_sent_prm_abort 4902 * 4903 * Inputs 4904 * (endpoint, asoc) 4905 * 4906 * The RFC does not explicitly address this issue, but is the route through the 4907 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4908 * 4909 * Outputs 4910 * (timers) 4911 */ 4912 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4913 const struct sctp_endpoint *ep, 4914 const struct sctp_association *asoc, 4915 const sctp_subtype_t type, 4916 void *arg, 4917 sctp_cmd_seq_t *commands) 4918 { 4919 /* Stop the T2-shutdown timer. */ 4920 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4921 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4922 4923 /* Stop the T5-shutdown guard timer. */ 4924 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4925 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4926 4927 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4928 } 4929 4930 /* 4931 * sctp_sf_cookie_echoed_prm_abort 4932 * 4933 * Inputs 4934 * (endpoint, asoc) 4935 * 4936 * The RFC does not explcitly address this issue, but is the route through the 4937 * state table when someone issues an abort while in COOKIE_ECHOED state. 4938 * 4939 * Outputs 4940 * (timers) 4941 */ 4942 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4943 const struct sctp_endpoint *ep, 4944 const struct sctp_association *asoc, 4945 const sctp_subtype_t type, 4946 void *arg, 4947 sctp_cmd_seq_t *commands) 4948 { 4949 /* The same T2 timer, so we should be able to use 4950 * common function with the SHUTDOWN-SENT state. 4951 */ 4952 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4953 } 4954 4955 /* 4956 * Process the REQUESTHEARTBEAT primitive 4957 * 4958 * 10.1 ULP-to-SCTP 4959 * J) Request Heartbeat 4960 * 4961 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4962 * 4963 * -> result 4964 * 4965 * Instructs the local endpoint to perform a HeartBeat on the specified 4966 * destination transport address of the given association. The returned 4967 * result should indicate whether the transmission of the HEARTBEAT 4968 * chunk to the destination address is successful. 4969 * 4970 * Mandatory attributes: 4971 * 4972 * o association id - local handle to the SCTP association 4973 * 4974 * o destination transport address - the transport address of the 4975 * association on which a heartbeat should be issued. 4976 */ 4977 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4978 const struct sctp_endpoint *ep, 4979 const struct sctp_association *asoc, 4980 const sctp_subtype_t type, 4981 void *arg, 4982 sctp_cmd_seq_t *commands) 4983 { 4984 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 4985 (struct sctp_transport *)arg, commands)) 4986 return SCTP_DISPOSITION_NOMEM; 4987 4988 /* 4989 * RFC 2960 (bis), section 8.3 4990 * 4991 * D) Request an on-demand HEARTBEAT on a specific destination 4992 * transport address of a given association. 4993 * 4994 * The endpoint should increment the respective error counter of 4995 * the destination transport address each time a HEARTBEAT is sent 4996 * to that address and not acknowledged within one RTO. 4997 * 4998 */ 4999 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5000 SCTP_TRANSPORT(arg)); 5001 return SCTP_DISPOSITION_CONSUME; 5002 } 5003 5004 /* 5005 * ADDIP Section 4.1 ASCONF Chunk Procedures 5006 * When an endpoint has an ASCONF signaled change to be sent to the 5007 * remote endpoint it should do A1 to A9 5008 */ 5009 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 5010 const struct sctp_association *asoc, 5011 const sctp_subtype_t type, 5012 void *arg, 5013 sctp_cmd_seq_t *commands) 5014 { 5015 struct sctp_chunk *chunk = arg; 5016 5017 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5018 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5019 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5020 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5021 return SCTP_DISPOSITION_CONSUME; 5022 } 5023 5024 /* 5025 * Ignore the primitive event 5026 * 5027 * The return value is the disposition of the primitive. 5028 */ 5029 sctp_disposition_t sctp_sf_ignore_primitive( 5030 const struct sctp_endpoint *ep, 5031 const struct sctp_association *asoc, 5032 const sctp_subtype_t type, 5033 void *arg, 5034 sctp_cmd_seq_t *commands) 5035 { 5036 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 5037 return SCTP_DISPOSITION_DISCARD; 5038 } 5039 5040 /*************************************************************************** 5041 * These are the state functions for the OTHER events. 5042 ***************************************************************************/ 5043 5044 /* 5045 * Start the shutdown negotiation. 5046 * 5047 * From Section 9.2: 5048 * Once all its outstanding data has been acknowledged, the endpoint 5049 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5050 * TSN Ack field the last sequential TSN it has received from the peer. 5051 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5052 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5053 * with the updated last sequential TSN received from its peer. 5054 * 5055 * The return value is the disposition. 5056 */ 5057 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5058 const struct sctp_endpoint *ep, 5059 const struct sctp_association *asoc, 5060 const sctp_subtype_t type, 5061 void *arg, 5062 sctp_cmd_seq_t *commands) 5063 { 5064 struct sctp_chunk *reply; 5065 5066 /* Once all its outstanding data has been acknowledged, the 5067 * endpoint shall send a SHUTDOWN chunk to its peer including 5068 * in the Cumulative TSN Ack field the last sequential TSN it 5069 * has received from the peer. 5070 */ 5071 reply = sctp_make_shutdown(asoc, NULL); 5072 if (!reply) 5073 goto nomem; 5074 5075 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5076 * T2-shutdown timer. 5077 */ 5078 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5079 5080 /* It shall then start the T2-shutdown timer */ 5081 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5082 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5083 5084 /* RFC 4960 Section 9.2 5085 * The sender of the SHUTDOWN MAY also start an overall guard timer 5086 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5087 */ 5088 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5089 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5090 5091 if (asoc->autoclose) 5092 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5093 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5094 5095 /* and enter the SHUTDOWN-SENT state. */ 5096 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5097 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5098 5099 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5100 * 5101 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5102 * or SHUTDOWN-ACK. 5103 */ 5104 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5105 5106 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5107 5108 return SCTP_DISPOSITION_CONSUME; 5109 5110 nomem: 5111 return SCTP_DISPOSITION_NOMEM; 5112 } 5113 5114 /* 5115 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5116 * 5117 * From Section 9.2: 5118 * 5119 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5120 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5121 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5122 * endpoint must re-send the SHUTDOWN ACK. 5123 * 5124 * The return value is the disposition. 5125 */ 5126 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5127 const struct sctp_endpoint *ep, 5128 const struct sctp_association *asoc, 5129 const sctp_subtype_t type, 5130 void *arg, 5131 sctp_cmd_seq_t *commands) 5132 { 5133 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5134 struct sctp_chunk *reply; 5135 5136 /* There are 2 ways of getting here: 5137 * 1) called in response to a SHUTDOWN chunk 5138 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5139 * 5140 * For the case (2), the arg parameter is set to NULL. We need 5141 * to check that we have a chunk before accessing it's fields. 5142 */ 5143 if (chunk) { 5144 if (!sctp_vtag_verify(chunk, asoc)) 5145 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 5146 5147 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5148 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5149 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 5150 commands); 5151 } 5152 5153 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5154 * shall send a SHUTDOWN ACK ... 5155 */ 5156 reply = sctp_make_shutdown_ack(asoc, chunk); 5157 if (!reply) 5158 goto nomem; 5159 5160 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5161 * the T2-shutdown timer. 5162 */ 5163 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5164 5165 /* and start/restart a T2-shutdown timer of its own, */ 5166 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5167 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5168 5169 if (asoc->autoclose) 5170 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5171 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5172 5173 /* Enter the SHUTDOWN-ACK-SENT state. */ 5174 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5175 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5176 5177 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5178 * 5179 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5180 * or SHUTDOWN-ACK. 5181 */ 5182 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5183 5184 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5185 5186 return SCTP_DISPOSITION_CONSUME; 5187 5188 nomem: 5189 return SCTP_DISPOSITION_NOMEM; 5190 } 5191 5192 /* 5193 * Ignore the event defined as other 5194 * 5195 * The return value is the disposition of the event. 5196 */ 5197 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 5198 const struct sctp_association *asoc, 5199 const sctp_subtype_t type, 5200 void *arg, 5201 sctp_cmd_seq_t *commands) 5202 { 5203 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5204 return SCTP_DISPOSITION_DISCARD; 5205 } 5206 5207 /************************************************************ 5208 * These are the state functions for handling timeout events. 5209 ************************************************************/ 5210 5211 /* 5212 * RTX Timeout 5213 * 5214 * Section: 6.3.3 Handle T3-rtx Expiration 5215 * 5216 * Whenever the retransmission timer T3-rtx expires for a destination 5217 * address, do the following: 5218 * [See below] 5219 * 5220 * The return value is the disposition of the chunk. 5221 */ 5222 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 5223 const struct sctp_association *asoc, 5224 const sctp_subtype_t type, 5225 void *arg, 5226 sctp_cmd_seq_t *commands) 5227 { 5228 struct sctp_transport *transport = arg; 5229 5230 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS); 5231 5232 if (asoc->overall_error_count >= asoc->max_retrans) { 5233 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5234 SCTP_ERROR(ETIMEDOUT)); 5235 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5236 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5237 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5238 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5239 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5240 return SCTP_DISPOSITION_DELETE_TCB; 5241 } 5242 5243 /* E1) For the destination address for which the timer 5244 * expires, adjust its ssthresh with rules defined in Section 5245 * 7.2.3 and set the cwnd <- MTU. 5246 */ 5247 5248 /* E2) For the destination address for which the timer 5249 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5250 * maximum value discussed in rule C7 above (RTO.max) may be 5251 * used to provide an upper bound to this doubling operation. 5252 */ 5253 5254 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5255 * outstanding DATA chunks for the address for which the 5256 * T3-rtx has expired will fit into a single packet, subject 5257 * to the MTU constraint for the path corresponding to the 5258 * destination transport address to which the retransmission 5259 * is being sent (this may be different from the address for 5260 * which the timer expires [see Section 6.4]). Call this 5261 * value K. Bundle and retransmit those K DATA chunks in a 5262 * single packet to the destination endpoint. 5263 * 5264 * Note: Any DATA chunks that were sent to the address for 5265 * which the T3-rtx timer expired but did not fit in one MTU 5266 * (rule E3 above), should be marked for retransmission and 5267 * sent as soon as cwnd allows (normally when a SACK arrives). 5268 */ 5269 5270 /* Do some failure management (Section 8.2). */ 5271 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5272 5273 /* NB: Rules E4 and F1 are implicit in R1. */ 5274 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5275 5276 return SCTP_DISPOSITION_CONSUME; 5277 } 5278 5279 /* 5280 * Generate delayed SACK on timeout 5281 * 5282 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5283 * 5284 * The guidelines on delayed acknowledgement algorithm specified in 5285 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5286 * acknowledgement SHOULD be generated for at least every second packet 5287 * (not every second DATA chunk) received, and SHOULD be generated 5288 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5289 * some situations it may be beneficial for an SCTP transmitter to be 5290 * more conservative than the algorithms detailed in this document 5291 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5292 * the following algorithms allow. 5293 */ 5294 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 5295 const struct sctp_association *asoc, 5296 const sctp_subtype_t type, 5297 void *arg, 5298 sctp_cmd_seq_t *commands) 5299 { 5300 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS); 5301 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5302 return SCTP_DISPOSITION_CONSUME; 5303 } 5304 5305 /* 5306 * sctp_sf_t1_init_timer_expire 5307 * 5308 * Section: 4 Note: 2 5309 * Verification Tag: 5310 * Inputs 5311 * (endpoint, asoc) 5312 * 5313 * RFC 2960 Section 4 Notes 5314 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5315 * and re-start the T1-init timer without changing state. This MUST 5316 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5317 * endpoint MUST abort the initialization process and report the 5318 * error to SCTP user. 5319 * 5320 * Outputs 5321 * (timers, events) 5322 * 5323 */ 5324 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 5325 const struct sctp_association *asoc, 5326 const sctp_subtype_t type, 5327 void *arg, 5328 sctp_cmd_seq_t *commands) 5329 { 5330 struct sctp_chunk *repl = NULL; 5331 struct sctp_bind_addr *bp; 5332 int attempts = asoc->init_err_counter + 1; 5333 5334 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5335 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS); 5336 5337 if (attempts <= asoc->max_init_attempts) { 5338 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5339 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5340 if (!repl) 5341 return SCTP_DISPOSITION_NOMEM; 5342 5343 /* Choose transport for INIT. */ 5344 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5345 SCTP_CHUNK(repl)); 5346 5347 /* Issue a sideeffect to do the needed accounting. */ 5348 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5349 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5350 5351 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5352 } else { 5353 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5354 " max_init_attempts: %d\n", 5355 attempts, asoc->max_init_attempts); 5356 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5357 SCTP_ERROR(ETIMEDOUT)); 5358 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5359 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5360 return SCTP_DISPOSITION_DELETE_TCB; 5361 } 5362 5363 return SCTP_DISPOSITION_CONSUME; 5364 } 5365 5366 /* 5367 * sctp_sf_t1_cookie_timer_expire 5368 * 5369 * Section: 4 Note: 2 5370 * Verification Tag: 5371 * Inputs 5372 * (endpoint, asoc) 5373 * 5374 * RFC 2960 Section 4 Notes 5375 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5376 * COOKIE ECHO and re-start the T1-cookie timer without changing 5377 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5378 * After that, the endpoint MUST abort the initialization process and 5379 * report the error to SCTP user. 5380 * 5381 * Outputs 5382 * (timers, events) 5383 * 5384 */ 5385 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 5386 const struct sctp_association *asoc, 5387 const sctp_subtype_t type, 5388 void *arg, 5389 sctp_cmd_seq_t *commands) 5390 { 5391 struct sctp_chunk *repl = NULL; 5392 int attempts = asoc->init_err_counter + 1; 5393 5394 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5395 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS); 5396 5397 if (attempts <= asoc->max_init_attempts) { 5398 repl = sctp_make_cookie_echo(asoc, NULL); 5399 if (!repl) 5400 return SCTP_DISPOSITION_NOMEM; 5401 5402 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5403 SCTP_CHUNK(repl)); 5404 /* Issue a sideeffect to do the needed accounting. */ 5405 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5406 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5407 5408 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5409 } else { 5410 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5411 SCTP_ERROR(ETIMEDOUT)); 5412 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5413 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5414 return SCTP_DISPOSITION_DELETE_TCB; 5415 } 5416 5417 return SCTP_DISPOSITION_CONSUME; 5418 } 5419 5420 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5421 * with the updated last sequential TSN received from its peer. 5422 * 5423 * An endpoint should limit the number of retransmissions of the 5424 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5425 * If this threshold is exceeded the endpoint should destroy the TCB and 5426 * MUST report the peer endpoint unreachable to the upper layer (and 5427 * thus the association enters the CLOSED state). The reception of any 5428 * packet from its peer (i.e. as the peer sends all of its queued DATA 5429 * chunks) should clear the endpoint's retransmission count and restart 5430 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5431 * all of its queued DATA chunks that have not yet been sent. 5432 */ 5433 sctp_disposition_t sctp_sf_t2_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 T2 expired.\n"); 5442 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5443 5444 ((struct sctp_association *)asoc)->shutdown_retries++; 5445 5446 if (asoc->overall_error_count >= asoc->max_retrans) { 5447 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5448 SCTP_ERROR(ETIMEDOUT)); 5449 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5450 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5451 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5452 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5453 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5454 return SCTP_DISPOSITION_DELETE_TCB; 5455 } 5456 5457 switch (asoc->state) { 5458 case SCTP_STATE_SHUTDOWN_SENT: 5459 reply = sctp_make_shutdown(asoc, NULL); 5460 break; 5461 5462 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5463 reply = sctp_make_shutdown_ack(asoc, NULL); 5464 break; 5465 5466 default: 5467 BUG(); 5468 break; 5469 } 5470 5471 if (!reply) 5472 goto nomem; 5473 5474 /* Do some failure management (Section 8.2). 5475 * If we remove the transport an SHUTDOWN was last sent to, don't 5476 * do failure management. 5477 */ 5478 if (asoc->shutdown_last_sent_to) 5479 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5480 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5481 5482 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5483 * the T2-shutdown timer. 5484 */ 5485 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5486 5487 /* Restart the T2-shutdown timer. */ 5488 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5489 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5490 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5491 return SCTP_DISPOSITION_CONSUME; 5492 5493 nomem: 5494 return SCTP_DISPOSITION_NOMEM; 5495 } 5496 5497 /* 5498 * ADDIP Section 4.1 ASCONF CHunk Procedures 5499 * If the T4 RTO timer expires the endpoint should do B1 to B5 5500 */ 5501 sctp_disposition_t sctp_sf_t4_timer_expire( 5502 const struct sctp_endpoint *ep, 5503 const struct sctp_association *asoc, 5504 const sctp_subtype_t type, 5505 void *arg, 5506 sctp_cmd_seq_t *commands) 5507 { 5508 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5509 struct sctp_transport *transport = chunk->transport; 5510 5511 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS); 5512 5513 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5514 * detection on the appropriate destination address as defined in 5515 * RFC2960 [5] section 8.1 and 8.2. 5516 */ 5517 if (transport) 5518 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5519 SCTP_TRANSPORT(transport)); 5520 5521 /* Reconfig T4 timer and transport. */ 5522 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5523 5524 /* ADDIP 4.1 B2) Increment the association error counters and perform 5525 * endpoint failure detection on the association as defined in 5526 * RFC2960 [5] section 8.1 and 8.2. 5527 * association error counter is incremented in SCTP_CMD_STRIKE. 5528 */ 5529 if (asoc->overall_error_count >= asoc->max_retrans) { 5530 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5531 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5532 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5533 SCTP_ERROR(ETIMEDOUT)); 5534 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5535 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5536 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5537 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5538 return SCTP_DISPOSITION_ABORT; 5539 } 5540 5541 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5542 * the ASCONF chunk was sent by doubling the RTO timer value. 5543 * This is done in SCTP_CMD_STRIKE. 5544 */ 5545 5546 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5547 * choose an alternate destination address (please refer to RFC2960 5548 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5549 * chunk, it MUST be the same (including its serial number) as the last 5550 * ASCONF sent. 5551 */ 5552 sctp_chunk_hold(asoc->addip_last_asconf); 5553 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5554 SCTP_CHUNK(asoc->addip_last_asconf)); 5555 5556 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5557 * destination is selected, then the RTO used will be that of the new 5558 * destination address. 5559 */ 5560 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5561 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5562 5563 return SCTP_DISPOSITION_CONSUME; 5564 } 5565 5566 /* sctpimpguide-05 Section 2.12.2 5567 * The sender of the SHUTDOWN MAY also start an overall guard timer 5568 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5569 * At the expiration of this timer the sender SHOULD abort the association 5570 * by sending an ABORT chunk. 5571 */ 5572 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 5573 const struct sctp_association *asoc, 5574 const sctp_subtype_t type, 5575 void *arg, 5576 sctp_cmd_seq_t *commands) 5577 { 5578 struct sctp_chunk *reply = NULL; 5579 5580 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5581 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5582 5583 reply = sctp_make_abort(asoc, NULL, 0); 5584 if (!reply) 5585 goto nomem; 5586 5587 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5588 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5589 SCTP_ERROR(ETIMEDOUT)); 5590 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5591 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5592 5593 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5594 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5595 5596 return SCTP_DISPOSITION_DELETE_TCB; 5597 nomem: 5598 return SCTP_DISPOSITION_NOMEM; 5599 } 5600 5601 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5602 * the association is automatically closed by starting the shutdown process. 5603 * The work that needs to be done is same as when SHUTDOWN is initiated by 5604 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5605 */ 5606 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5607 const struct sctp_endpoint *ep, 5608 const struct sctp_association *asoc, 5609 const sctp_subtype_t type, 5610 void *arg, 5611 sctp_cmd_seq_t *commands) 5612 { 5613 int disposition; 5614 5615 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS); 5616 5617 /* From 9.2 Shutdown of an Association 5618 * Upon receipt of the SHUTDOWN primitive from its upper 5619 * layer, the endpoint enters SHUTDOWN-PENDING state and 5620 * remains there until all outstanding data has been 5621 * acknowledged by its peer. The endpoint accepts no new data 5622 * from its upper layer, but retransmits data to the far end 5623 * if necessary to fill gaps. 5624 */ 5625 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5626 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5627 5628 disposition = SCTP_DISPOSITION_CONSUME; 5629 if (sctp_outq_is_empty(&asoc->outqueue)) { 5630 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 5631 arg, commands); 5632 } 5633 return disposition; 5634 } 5635 5636 /***************************************************************************** 5637 * These are sa state functions which could apply to all types of events. 5638 ****************************************************************************/ 5639 5640 /* 5641 * This table entry is not implemented. 5642 * 5643 * Inputs 5644 * (endpoint, asoc, chunk) 5645 * 5646 * The return value is the disposition of the chunk. 5647 */ 5648 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 5649 const struct sctp_association *asoc, 5650 const sctp_subtype_t type, 5651 void *arg, 5652 sctp_cmd_seq_t *commands) 5653 { 5654 return SCTP_DISPOSITION_NOT_IMPL; 5655 } 5656 5657 /* 5658 * This table entry represents a bug. 5659 * 5660 * Inputs 5661 * (endpoint, asoc, chunk) 5662 * 5663 * The return value is the disposition of the chunk. 5664 */ 5665 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 5666 const struct sctp_association *asoc, 5667 const sctp_subtype_t type, 5668 void *arg, 5669 sctp_cmd_seq_t *commands) 5670 { 5671 return SCTP_DISPOSITION_BUG; 5672 } 5673 5674 /* 5675 * This table entry represents the firing of a timer in the wrong state. 5676 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5677 * when the association is in the wrong state. This event should 5678 * be ignored, so as to prevent any rearming of the timer. 5679 * 5680 * Inputs 5681 * (endpoint, asoc, chunk) 5682 * 5683 * The return value is the disposition of the chunk. 5684 */ 5685 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 5686 const struct sctp_association *asoc, 5687 const sctp_subtype_t type, 5688 void *arg, 5689 sctp_cmd_seq_t *commands) 5690 { 5691 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5692 return SCTP_DISPOSITION_CONSUME; 5693 } 5694 5695 /******************************************************************** 5696 * 2nd Level Abstractions 5697 ********************************************************************/ 5698 5699 /* Pull the SACK chunk based on the SACK header. */ 5700 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5701 { 5702 struct sctp_sackhdr *sack; 5703 unsigned int len; 5704 __u16 num_blocks; 5705 __u16 num_dup_tsns; 5706 5707 /* Protect ourselves from reading too far into 5708 * the skb from a bogus sender. 5709 */ 5710 sack = (struct sctp_sackhdr *) chunk->skb->data; 5711 5712 num_blocks = ntohs(sack->num_gap_ack_blocks); 5713 num_dup_tsns = ntohs(sack->num_dup_tsns); 5714 len = sizeof(struct sctp_sackhdr); 5715 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5716 if (len > chunk->skb->len) 5717 return NULL; 5718 5719 skb_pull(chunk->skb, len); 5720 5721 return sack; 5722 } 5723 5724 /* Create an ABORT packet to be sent as a response, with the specified 5725 * error causes. 5726 */ 5727 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5728 const struct sctp_association *asoc, 5729 struct sctp_chunk *chunk, 5730 const void *payload, 5731 size_t paylen) 5732 { 5733 struct sctp_packet *packet; 5734 struct sctp_chunk *abort; 5735 5736 packet = sctp_ootb_pkt_new(asoc, chunk); 5737 5738 if (packet) { 5739 /* Make an ABORT. 5740 * The T bit will be set if the asoc is NULL. 5741 */ 5742 abort = sctp_make_abort(asoc, chunk, paylen); 5743 if (!abort) { 5744 sctp_ootb_pkt_free(packet); 5745 return NULL; 5746 } 5747 5748 /* Reflect vtag if T-Bit is set */ 5749 if (sctp_test_T_bit(abort)) 5750 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5751 5752 /* Add specified error causes, i.e., payload, to the 5753 * end of the chunk. 5754 */ 5755 sctp_addto_chunk(abort, paylen, payload); 5756 5757 /* Set the skb to the belonging sock for accounting. */ 5758 abort->skb->sk = ep->base.sk; 5759 5760 sctp_packet_append_chunk(packet, abort); 5761 5762 } 5763 5764 return packet; 5765 } 5766 5767 /* Allocate a packet for responding in the OOTB conditions. */ 5768 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5769 const struct sctp_chunk *chunk) 5770 { 5771 struct sctp_packet *packet; 5772 struct sctp_transport *transport; 5773 __u16 sport; 5774 __u16 dport; 5775 __u32 vtag; 5776 5777 /* Get the source and destination port from the inbound packet. */ 5778 sport = ntohs(chunk->sctp_hdr->dest); 5779 dport = ntohs(chunk->sctp_hdr->source); 5780 5781 /* The V-tag is going to be the same as the inbound packet if no 5782 * association exists, otherwise, use the peer's vtag. 5783 */ 5784 if (asoc) { 5785 /* Special case the INIT-ACK as there is no peer's vtag 5786 * yet. 5787 */ 5788 switch(chunk->chunk_hdr->type) { 5789 case SCTP_CID_INIT_ACK: 5790 { 5791 sctp_initack_chunk_t *initack; 5792 5793 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5794 vtag = ntohl(initack->init_hdr.init_tag); 5795 break; 5796 } 5797 default: 5798 vtag = asoc->peer.i.init_tag; 5799 break; 5800 } 5801 } else { 5802 /* Special case the INIT and stale COOKIE_ECHO as there is no 5803 * vtag yet. 5804 */ 5805 switch(chunk->chunk_hdr->type) { 5806 case SCTP_CID_INIT: 5807 { 5808 sctp_init_chunk_t *init; 5809 5810 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5811 vtag = ntohl(init->init_hdr.init_tag); 5812 break; 5813 } 5814 default: 5815 vtag = ntohl(chunk->sctp_hdr->vtag); 5816 break; 5817 } 5818 } 5819 5820 /* Make a transport for the bucket, Eliza... */ 5821 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5822 if (!transport) 5823 goto nomem; 5824 5825 /* Cache a route for the transport with the chunk's destination as 5826 * the source address. 5827 */ 5828 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5829 sctp_sk(sctp_get_ctl_sock())); 5830 5831 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5832 packet = sctp_packet_config(packet, vtag, 0); 5833 5834 return packet; 5835 5836 nomem: 5837 return NULL; 5838 } 5839 5840 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5841 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5842 { 5843 sctp_transport_free(packet->transport); 5844 } 5845 5846 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5847 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5848 const struct sctp_association *asoc, 5849 const struct sctp_chunk *chunk, 5850 sctp_cmd_seq_t *commands, 5851 struct sctp_chunk *err_chunk) 5852 { 5853 struct sctp_packet *packet; 5854 5855 if (err_chunk) { 5856 packet = sctp_ootb_pkt_new(asoc, chunk); 5857 if (packet) { 5858 struct sctp_signed_cookie *cookie; 5859 5860 /* Override the OOTB vtag from the cookie. */ 5861 cookie = chunk->subh.cookie_hdr; 5862 packet->vtag = cookie->c.peer_vtag; 5863 5864 /* Set the skb to the belonging sock for accounting. */ 5865 err_chunk->skb->sk = ep->base.sk; 5866 sctp_packet_append_chunk(packet, err_chunk); 5867 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5868 SCTP_PACKET(packet)); 5869 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5870 } else 5871 sctp_chunk_free (err_chunk); 5872 } 5873 } 5874 5875 5876 /* Process a data chunk */ 5877 static int sctp_eat_data(const struct sctp_association *asoc, 5878 struct sctp_chunk *chunk, 5879 sctp_cmd_seq_t *commands) 5880 { 5881 sctp_datahdr_t *data_hdr; 5882 struct sctp_chunk *err; 5883 size_t datalen; 5884 sctp_verb_t deliver; 5885 int tmp; 5886 __u32 tsn; 5887 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 5888 struct sock *sk = asoc->base.sk; 5889 u16 ssn; 5890 u16 sid; 5891 u8 ordered = 0; 5892 5893 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5894 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5895 5896 tsn = ntohl(data_hdr->tsn); 5897 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5898 5899 /* ASSERT: Now skb->data is really the user data. */ 5900 5901 /* Process ECN based congestion. 5902 * 5903 * Since the chunk structure is reused for all chunks within 5904 * a packet, we use ecn_ce_done to track if we've already 5905 * done CE processing for this packet. 5906 * 5907 * We need to do ECN processing even if we plan to discard the 5908 * chunk later. 5909 */ 5910 5911 if (!chunk->ecn_ce_done) { 5912 struct sctp_af *af; 5913 chunk->ecn_ce_done = 1; 5914 5915 af = sctp_get_af_specific( 5916 ipver2af(ip_hdr(chunk->skb)->version)); 5917 5918 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5919 /* Do real work as sideffect. */ 5920 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5921 SCTP_U32(tsn)); 5922 } 5923 } 5924 5925 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5926 if (tmp < 0) { 5927 /* The TSN is too high--silently discard the chunk and 5928 * count on it getting retransmitted later. 5929 */ 5930 return SCTP_IERROR_HIGH_TSN; 5931 } else if (tmp > 0) { 5932 /* This is a duplicate. Record it. */ 5933 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5934 return SCTP_IERROR_DUP_TSN; 5935 } 5936 5937 /* This is a new TSN. */ 5938 5939 /* Discard if there is no room in the receive window. 5940 * Actually, allow a little bit of overflow (up to a MTU). 5941 */ 5942 datalen = ntohs(chunk->chunk_hdr->length); 5943 datalen -= sizeof(sctp_data_chunk_t); 5944 5945 deliver = SCTP_CMD_CHUNK_ULP; 5946 5947 /* Think about partial delivery. */ 5948 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5949 5950 /* Even if we don't accept this chunk there is 5951 * memory pressure. 5952 */ 5953 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5954 } 5955 5956 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5957 * seems a bit troublesome in that frag_point varies based on 5958 * PMTU. In cases, such as loopback, this might be a rather 5959 * large spill over. 5960 */ 5961 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 5962 (datalen > asoc->rwnd + asoc->frag_point))) { 5963 5964 /* If this is the next TSN, consider reneging to make 5965 * room. Note: Playing nice with a confused sender. A 5966 * malicious sender can still eat up all our buffer 5967 * space and in the future we may want to detect and 5968 * do more drastic reneging. 5969 */ 5970 if (sctp_tsnmap_has_gap(map) && 5971 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5972 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5973 deliver = SCTP_CMD_RENEGE; 5974 } else { 5975 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5976 "rwnd: %d\n", tsn, datalen, 5977 asoc->rwnd); 5978 return SCTP_IERROR_IGNORE_TSN; 5979 } 5980 } 5981 5982 /* 5983 * Also try to renege to limit our memory usage in the event that 5984 * we are under memory pressure 5985 * If we can't renege, don't worry about it, the sk_rmem_schedule 5986 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 5987 * memory usage too much 5988 */ 5989 if (*sk->sk_prot_creator->memory_pressure) { 5990 if (sctp_tsnmap_has_gap(map) && 5991 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5992 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 5993 deliver = SCTP_CMD_RENEGE; 5994 } 5995 } 5996 5997 /* 5998 * Section 3.3.10.9 No User Data (9) 5999 * 6000 * Cause of error 6001 * --------------- 6002 * No User Data: This error cause is returned to the originator of a 6003 * DATA chunk if a received DATA chunk has no user data. 6004 */ 6005 if (unlikely(0 == datalen)) { 6006 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6007 if (err) { 6008 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6009 SCTP_CHUNK(err)); 6010 } 6011 /* We are going to ABORT, so we might as well stop 6012 * processing the rest of the chunks in the packet. 6013 */ 6014 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 6015 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6016 SCTP_ERROR(ECONNABORTED)); 6017 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6018 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6019 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 6020 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 6021 return SCTP_IERROR_NO_DATA; 6022 } 6023 6024 chunk->data_accepted = 1; 6025 6026 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6027 * if we renege and the chunk arrives again. 6028 */ 6029 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 6030 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 6031 else { 6032 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 6033 ordered = 1; 6034 } 6035 6036 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6037 * 6038 * If an endpoint receive a DATA chunk with an invalid stream 6039 * identifier, it shall acknowledge the reception of the DATA chunk 6040 * following the normal procedure, immediately send an ERROR chunk 6041 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6042 * and discard the DATA chunk. 6043 */ 6044 sid = ntohs(data_hdr->stream); 6045 if (sid >= asoc->c.sinit_max_instreams) { 6046 /* Mark tsn as received even though we drop it */ 6047 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6048 6049 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6050 &data_hdr->stream, 6051 sizeof(data_hdr->stream)); 6052 if (err) 6053 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6054 SCTP_CHUNK(err)); 6055 return SCTP_IERROR_BAD_STREAM; 6056 } 6057 6058 /* Check to see if the SSN is possible for this TSN. 6059 * The biggest gap we can record is 4K wide. Since SSNs wrap 6060 * at an unsigned short, there is no way that an SSN can 6061 * wrap and for a valid TSN. We can simply check if the current 6062 * SSN is smaller then the next expected one. If it is, it wrapped 6063 * and is invalid. 6064 */ 6065 ssn = ntohs(data_hdr->ssn); 6066 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6067 return SCTP_IERROR_PROTO_VIOLATION; 6068 } 6069 6070 /* Send the data up to the user. Note: Schedule the 6071 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6072 * chunk needs the updated rwnd. 6073 */ 6074 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6075 6076 return SCTP_IERROR_NO_ERROR; 6077 } 6078