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