1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <lksctp-developers@lists.sourceforge.net> 32 * 33 * Or submit a bug report through the following website: 34 * http://www.sf.net/projects/lksctp 35 * 36 * Written or modified by: 37 * La Monte H.P. Yarroll <piggy@acm.org> 38 * Karl Knutson <karl@athena.chicago.il.us> 39 * Mathew Kotowsky <kotowsky@sctp.org> 40 * Sridhar Samudrala <samudrala@us.ibm.com> 41 * Jon Grimm <jgrimm@us.ibm.com> 42 * Hui Huang <hui.huang@nokia.com> 43 * Dajiang Zhang <dajiang.zhang@nokia.com> 44 * Daisy Chang <daisyc@us.ibm.com> 45 * Ardelle Fan <ardelle.fan@intel.com> 46 * Ryan Layer <rmlayer@us.ibm.com> 47 * Kevin Gao <kevin.gao@intel.com> 48 * 49 * Any bugs reported given to us we will try to fix... any fixes shared will 50 * be incorporated into the next SCTP release. 51 */ 52 53 #include <linux/types.h> 54 #include <linux/kernel.h> 55 #include <linux/ip.h> 56 #include <linux/ipv6.h> 57 #include <linux/net.h> 58 #include <linux/inet.h> 59 #include <net/sock.h> 60 #include <net/inet_ecn.h> 61 #include <linux/skbuff.h> 62 #include <net/sctp/sctp.h> 63 #include <net/sctp/sm.h> 64 #include <net/sctp/structs.h> 65 66 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 67 const struct sctp_association *asoc, 68 struct sctp_chunk *chunk, 69 const void *payload, 70 size_t paylen); 71 static int sctp_eat_data(const struct sctp_association *asoc, 72 struct sctp_chunk *chunk, 73 sctp_cmd_seq_t *commands); 74 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 75 const struct sctp_chunk *chunk); 76 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 77 const struct sctp_association *asoc, 78 const struct sctp_chunk *chunk, 79 sctp_cmd_seq_t *commands, 80 struct sctp_chunk *err_chunk); 81 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 82 const struct sctp_association *asoc, 83 const sctp_subtype_t type, 84 void *arg, 85 sctp_cmd_seq_t *commands); 86 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 87 const struct sctp_association *asoc, 88 const sctp_subtype_t type, 89 void *arg, 90 sctp_cmd_seq_t *commands); 91 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 92 const struct sctp_association *asoc, 93 const sctp_subtype_t type, 94 void *arg, 95 sctp_cmd_seq_t *commands); 96 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 97 98 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 99 __be16 error, int sk_err, 100 const struct sctp_association *asoc, 101 struct sctp_transport *transport); 102 103 static sctp_disposition_t sctp_sf_abort_violation( 104 const struct sctp_endpoint *ep, 105 const struct sctp_association *asoc, 106 void *arg, 107 sctp_cmd_seq_t *commands, 108 const __u8 *payload, 109 const size_t paylen); 110 111 static sctp_disposition_t sctp_sf_violation_chunklen( 112 const struct sctp_endpoint *ep, 113 const struct sctp_association *asoc, 114 const sctp_subtype_t type, 115 void *arg, 116 sctp_cmd_seq_t *commands); 117 118 static sctp_disposition_t sctp_sf_violation_paramlen( 119 const struct sctp_endpoint *ep, 120 const struct sctp_association *asoc, 121 const sctp_subtype_t type, 122 void *arg, void *ext, 123 sctp_cmd_seq_t *commands); 124 125 static sctp_disposition_t sctp_sf_violation_ctsn( 126 const struct sctp_endpoint *ep, 127 const struct sctp_association *asoc, 128 const sctp_subtype_t type, 129 void *arg, 130 sctp_cmd_seq_t *commands); 131 132 static sctp_disposition_t sctp_sf_violation_chunk( 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const sctp_subtype_t type, 136 void *arg, 137 sctp_cmd_seq_t *commands); 138 139 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 140 const struct sctp_association *asoc, 141 const sctp_subtype_t type, 142 struct sctp_chunk *chunk); 143 144 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 145 const struct sctp_association *asoc, 146 const sctp_subtype_t type, 147 void *arg, 148 sctp_cmd_seq_t *commands); 149 150 /* Small helper function that checks if the chunk length 151 * is of the appropriate length. The 'required_length' argument 152 * is set to be the size of a specific chunk we are testing. 153 * Return Values: 1 = Valid length 154 * 0 = Invalid length 155 * 156 */ 157 static inline int 158 sctp_chunk_length_valid(struct sctp_chunk *chunk, 159 __u16 required_length) 160 { 161 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 162 163 if (unlikely(chunk_length < required_length)) 164 return 0; 165 166 return 1; 167 } 168 169 /********************************************************** 170 * These are the state functions for handling chunk events. 171 **********************************************************/ 172 173 /* 174 * Process the final SHUTDOWN COMPLETE. 175 * 176 * Section: 4 (C) (diagram), 9.2 177 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 178 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 179 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 180 * should stop the T2-shutdown timer and remove all knowledge of the 181 * association (and thus the association enters the CLOSED state). 182 * 183 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 184 * C) Rules for packet carrying SHUTDOWN COMPLETE: 185 * ... 186 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 187 * if the Verification Tag field of the packet matches its own tag and 188 * the T bit is not set 189 * OR 190 * it is set to its peer's tag and the T bit is set in the Chunk 191 * Flags. 192 * Otherwise, the receiver MUST silently discard the packet 193 * and take no further action. An endpoint MUST ignore the 194 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 195 * 196 * Inputs 197 * (endpoint, asoc, chunk) 198 * 199 * Outputs 200 * (asoc, reply_msg, msg_up, timers, counters) 201 * 202 * The return value is the disposition of the chunk. 203 */ 204 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, 205 const struct sctp_association *asoc, 206 const sctp_subtype_t type, 207 void *arg, 208 sctp_cmd_seq_t *commands) 209 { 210 struct sctp_chunk *chunk = arg; 211 struct sctp_ulpevent *ev; 212 213 if (!sctp_vtag_verify_either(chunk, asoc)) 214 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 215 216 /* RFC 2960 6.10 Bundling 217 * 218 * An endpoint MUST NOT bundle INIT, INIT ACK or 219 * SHUTDOWN COMPLETE with any other chunks. 220 */ 221 if (!chunk->singleton) 222 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 223 224 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 225 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 226 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 227 commands); 228 229 /* RFC 2960 10.2 SCTP-to-ULP 230 * 231 * H) SHUTDOWN COMPLETE notification 232 * 233 * When SCTP completes the shutdown procedures (section 9.2) this 234 * notification is passed to the upper layer. 235 */ 236 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 237 0, 0, 0, NULL, GFP_ATOMIC); 238 if (ev) 239 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 240 SCTP_ULPEVENT(ev)); 241 242 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 243 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 244 * not the chunk should be discarded. If the endpoint is in 245 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 246 * T2-shutdown timer and remove all knowledge of the 247 * association (and thus the association enters the CLOSED 248 * state). 249 */ 250 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 251 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 252 253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 254 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 255 256 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 257 SCTP_STATE(SCTP_STATE_CLOSED)); 258 259 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 260 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 261 262 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 263 264 return SCTP_DISPOSITION_DELETE_TCB; 265 } 266 267 /* 268 * Respond to a normal INIT chunk. 269 * We are the side that is being asked for an association. 270 * 271 * Section: 5.1 Normal Establishment of an Association, B 272 * B) "Z" shall respond immediately with an INIT ACK chunk. The 273 * destination IP address of the INIT ACK MUST be set to the source 274 * IP address of the INIT to which this INIT ACK is responding. In 275 * the response, besides filling in other parameters, "Z" must set the 276 * Verification Tag field to Tag_A, and also provide its own 277 * Verification Tag (Tag_Z) in the Initiate Tag field. 278 * 279 * Verification Tag: Must be 0. 280 * 281 * Inputs 282 * (endpoint, asoc, chunk) 283 * 284 * Outputs 285 * (asoc, reply_msg, msg_up, timers, counters) 286 * 287 * The return value is the disposition of the chunk. 288 */ 289 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 290 const struct sctp_association *asoc, 291 const sctp_subtype_t type, 292 void *arg, 293 sctp_cmd_seq_t *commands) 294 { 295 struct sctp_chunk *chunk = arg; 296 struct sctp_chunk *repl; 297 struct sctp_association *new_asoc; 298 struct sctp_chunk *err_chunk; 299 struct sctp_packet *packet; 300 sctp_unrecognized_param_t *unk_param; 301 int len; 302 303 /* 6.10 Bundling 304 * An endpoint MUST NOT bundle INIT, INIT ACK or 305 * SHUTDOWN COMPLETE with any other chunks. 306 * 307 * IG Section 2.11.2 308 * Furthermore, we require that the receiver of an INIT chunk MUST 309 * enforce these rules by silently discarding an arriving packet 310 * with an INIT chunk that is bundled with other chunks. 311 */ 312 if (!chunk->singleton) 313 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 314 315 /* If the packet is an OOTB packet which is temporarily on the 316 * control endpoint, respond with an ABORT. 317 */ 318 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) { 319 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 320 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 321 } 322 323 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 324 * Tag. 325 */ 326 if (chunk->sctp_hdr->vtag != 0) 327 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 328 329 /* Make sure that the INIT chunk has a valid length. 330 * Normally, this would cause an ABORT with a Protocol Violation 331 * error, but since we don't have an association, we'll 332 * just discard the packet. 333 */ 334 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 335 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 336 337 /* If the INIT is coming toward a closing socket, we'll send back 338 * and ABORT. Essentially, this catches the race of INIT being 339 * backloged to the socket at the same time as the user isses close(). 340 * Since the socket and all its associations are going away, we 341 * can treat this OOTB 342 */ 343 if (sctp_sstate(ep->base.sk, CLOSING)) 344 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 345 346 /* Verify the INIT chunk before processing it. */ 347 err_chunk = NULL; 348 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 349 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 350 &err_chunk)) { 351 /* This chunk contains fatal error. It is to be discarded. 352 * Send an ABORT, with causes if there is any. 353 */ 354 if (err_chunk) { 355 packet = sctp_abort_pkt_new(ep, asoc, arg, 356 (__u8 *)(err_chunk->chunk_hdr) + 357 sizeof(sctp_chunkhdr_t), 358 ntohs(err_chunk->chunk_hdr->length) - 359 sizeof(sctp_chunkhdr_t)); 360 361 sctp_chunk_free(err_chunk); 362 363 if (packet) { 364 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 365 SCTP_PACKET(packet)); 366 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 367 return SCTP_DISPOSITION_CONSUME; 368 } else { 369 return SCTP_DISPOSITION_NOMEM; 370 } 371 } else { 372 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 373 commands); 374 } 375 } 376 377 /* Grab the INIT header. */ 378 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 379 380 /* Tag the variable length parameters. */ 381 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 382 383 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 384 if (!new_asoc) 385 goto nomem; 386 387 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 388 sctp_scope(sctp_source(chunk)), 389 GFP_ATOMIC) < 0) 390 goto nomem_init; 391 392 /* The call, sctp_process_init(), can fail on memory allocation. */ 393 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 394 sctp_source(chunk), 395 (sctp_init_chunk_t *)chunk->chunk_hdr, 396 GFP_ATOMIC)) 397 goto nomem_init; 398 399 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 400 401 /* If there are errors need to be reported for unknown parameters, 402 * make sure to reserve enough room in the INIT ACK for them. 403 */ 404 len = 0; 405 if (err_chunk) 406 len = ntohs(err_chunk->chunk_hdr->length) - 407 sizeof(sctp_chunkhdr_t); 408 409 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 410 if (!repl) 411 goto nomem_init; 412 413 /* If there are errors need to be reported for unknown parameters, 414 * include them in the outgoing INIT ACK as "Unrecognized parameter" 415 * parameter. 416 */ 417 if (err_chunk) { 418 /* Get the "Unrecognized parameter" parameter(s) out of the 419 * ERROR chunk generated by sctp_verify_init(). Since the 420 * error cause code for "unknown parameter" and the 421 * "Unrecognized parameter" type is the same, we can 422 * construct the parameters in INIT ACK by copying the 423 * ERROR causes over. 424 */ 425 unk_param = (sctp_unrecognized_param_t *) 426 ((__u8 *)(err_chunk->chunk_hdr) + 427 sizeof(sctp_chunkhdr_t)); 428 /* Replace the cause code with the "Unrecognized parameter" 429 * parameter type. 430 */ 431 sctp_addto_chunk(repl, len, unk_param); 432 sctp_chunk_free(err_chunk); 433 } 434 435 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 436 437 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 438 439 /* 440 * Note: After sending out INIT ACK with the State Cookie parameter, 441 * "Z" MUST NOT allocate any resources, nor keep any states for the 442 * new association. Otherwise, "Z" will be vulnerable to resource 443 * attacks. 444 */ 445 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 446 447 return SCTP_DISPOSITION_DELETE_TCB; 448 449 nomem_init: 450 sctp_association_free(new_asoc); 451 nomem: 452 if (err_chunk) 453 sctp_chunk_free(err_chunk); 454 return SCTP_DISPOSITION_NOMEM; 455 } 456 457 /* 458 * Respond to a normal INIT ACK chunk. 459 * We are the side that is initiating the association. 460 * 461 * Section: 5.1 Normal Establishment of an Association, C 462 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 463 * timer and leave COOKIE-WAIT state. "A" shall then send the State 464 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 465 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 466 * 467 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 468 * DATA chunks, but it MUST be the first chunk in the packet and 469 * until the COOKIE ACK is returned the sender MUST NOT send any 470 * other packets to the peer. 471 * 472 * Verification Tag: 3.3.3 473 * If the value of the Initiate Tag in a received INIT ACK chunk is 474 * found to be 0, the receiver MUST treat it as an error and close the 475 * association by transmitting an ABORT. 476 * 477 * Inputs 478 * (endpoint, asoc, chunk) 479 * 480 * Outputs 481 * (asoc, reply_msg, msg_up, timers, counters) 482 * 483 * The return value is the disposition of the chunk. 484 */ 485 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, 486 const struct sctp_association *asoc, 487 const sctp_subtype_t type, 488 void *arg, 489 sctp_cmd_seq_t *commands) 490 { 491 struct sctp_chunk *chunk = arg; 492 sctp_init_chunk_t *initchunk; 493 struct sctp_chunk *err_chunk; 494 struct sctp_packet *packet; 495 496 if (!sctp_vtag_verify(chunk, asoc)) 497 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 498 499 /* 6.10 Bundling 500 * An endpoint MUST NOT bundle INIT, INIT ACK or 501 * SHUTDOWN COMPLETE with any other chunks. 502 */ 503 if (!chunk->singleton) 504 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 505 506 /* Make sure that the INIT-ACK chunk has a valid length */ 507 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 508 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 509 commands); 510 /* Grab the INIT header. */ 511 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 512 513 /* Verify the INIT chunk before processing it. */ 514 err_chunk = NULL; 515 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 516 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 517 &err_chunk)) { 518 519 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 520 521 /* This chunk contains fatal error. It is to be discarded. 522 * Send an ABORT, with causes. If there are no causes, 523 * then there wasn't enough memory. Just terminate 524 * the association. 525 */ 526 if (err_chunk) { 527 packet = sctp_abort_pkt_new(ep, asoc, arg, 528 (__u8 *)(err_chunk->chunk_hdr) + 529 sizeof(sctp_chunkhdr_t), 530 ntohs(err_chunk->chunk_hdr->length) - 531 sizeof(sctp_chunkhdr_t)); 532 533 sctp_chunk_free(err_chunk); 534 535 if (packet) { 536 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 537 SCTP_PACKET(packet)); 538 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 539 error = SCTP_ERROR_INV_PARAM; 540 } 541 } 542 543 /* SCTP-AUTH, Section 6.3: 544 * It should be noted that if the receiver wants to tear 545 * down an association in an authenticated way only, the 546 * handling of malformed packets should not result in 547 * tearing down the association. 548 * 549 * This means that if we only want to abort associations 550 * in an authenticated way (i.e AUTH+ABORT), then we 551 * can't destroy this association just becuase the packet 552 * was malformed. 553 */ 554 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 555 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 556 557 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 558 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, 559 asoc, chunk->transport); 560 } 561 562 /* Tag the variable length parameters. Note that we never 563 * convert the parameters in an INIT chunk. 564 */ 565 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 566 567 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 568 569 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 570 SCTP_PEER_INIT(initchunk)); 571 572 /* Reset init error count upon receipt of INIT-ACK. */ 573 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 574 575 /* 5.1 C) "A" shall stop the T1-init timer and leave 576 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 577 * timer, and enter the COOKIE-ECHOED state. 578 */ 579 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 580 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 581 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 582 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 583 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 584 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 585 586 /* SCTP-AUTH: genereate the assocition shared keys so that 587 * we can potentially signe the COOKIE-ECHO. 588 */ 589 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 590 591 /* 5.1 C) "A" shall then send the State Cookie received in the 592 * INIT ACK chunk in a COOKIE ECHO chunk, ... 593 */ 594 /* If there is any errors to report, send the ERROR chunk generated 595 * for unknown parameters as well. 596 */ 597 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 598 SCTP_CHUNK(err_chunk)); 599 600 return SCTP_DISPOSITION_CONSUME; 601 } 602 603 /* 604 * Respond to a normal COOKIE ECHO chunk. 605 * We are the side that is being asked for an association. 606 * 607 * Section: 5.1 Normal Establishment of an Association, D 608 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 609 * with a COOKIE ACK chunk after building a TCB and moving to 610 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 611 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 612 * chunk MUST be the first chunk in the packet. 613 * 614 * IMPLEMENTATION NOTE: An implementation may choose to send the 615 * Communication Up notification to the SCTP user upon reception 616 * of a valid COOKIE ECHO chunk. 617 * 618 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 619 * D) Rules for packet carrying a COOKIE ECHO 620 * 621 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 622 * Initial Tag received in the INIT ACK. 623 * 624 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 625 * 626 * Inputs 627 * (endpoint, asoc, chunk) 628 * 629 * Outputs 630 * (asoc, reply_msg, msg_up, timers, counters) 631 * 632 * The return value is the disposition of the chunk. 633 */ 634 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, 635 const struct sctp_association *asoc, 636 const sctp_subtype_t type, void *arg, 637 sctp_cmd_seq_t *commands) 638 { 639 struct sctp_chunk *chunk = arg; 640 struct sctp_association *new_asoc; 641 sctp_init_chunk_t *peer_init; 642 struct sctp_chunk *repl; 643 struct sctp_ulpevent *ev, *ai_ev = NULL; 644 int error = 0; 645 struct sctp_chunk *err_chk_p; 646 struct sock *sk; 647 648 /* If the packet is an OOTB packet which is temporarily on the 649 * control endpoint, respond with an ABORT. 650 */ 651 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) { 652 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 653 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 654 } 655 656 /* Make sure that the COOKIE_ECHO chunk has a valid length. 657 * In this case, we check that we have enough for at least a 658 * chunk header. More detailed verification is done 659 * in sctp_unpack_cookie(). 660 */ 661 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 662 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 663 664 /* If the endpoint is not listening or if the number of associations 665 * on the TCP-style socket exceed the max backlog, respond with an 666 * ABORT. 667 */ 668 sk = ep->base.sk; 669 if (!sctp_sstate(sk, LISTENING) || 670 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 671 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 672 673 /* "Decode" the chunk. We have no optional parameters so we 674 * are in good shape. 675 */ 676 chunk->subh.cookie_hdr = 677 (struct sctp_signed_cookie *)chunk->skb->data; 678 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 679 sizeof(sctp_chunkhdr_t))) 680 goto nomem; 681 682 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 683 * "Z" will reply with a COOKIE ACK chunk after building a TCB 684 * and moving to the ESTABLISHED state. 685 */ 686 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 687 &err_chk_p); 688 689 /* FIXME: 690 * If the re-build failed, what is the proper error path 691 * from here? 692 * 693 * [We should abort the association. --piggy] 694 */ 695 if (!new_asoc) { 696 /* FIXME: Several errors are possible. A bad cookie should 697 * be silently discarded, but think about logging it too. 698 */ 699 switch (error) { 700 case -SCTP_IERROR_NOMEM: 701 goto nomem; 702 703 case -SCTP_IERROR_STALE_COOKIE: 704 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 705 err_chk_p); 706 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 707 708 case -SCTP_IERROR_BAD_SIG: 709 default: 710 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 711 } 712 } 713 714 715 /* Delay state machine commands until later. 716 * 717 * Re-build the bind address for the association is done in 718 * the sctp_unpack_cookie() already. 719 */ 720 /* This is a brand-new association, so these are not yet side 721 * effects--it is safe to run them here. 722 */ 723 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 724 725 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 726 &chunk->subh.cookie_hdr->c.peer_addr, 727 peer_init, GFP_ATOMIC)) 728 goto nomem_init; 729 730 /* SCTP-AUTH: Now that we've populate required fields in 731 * sctp_process_init, set up the assocaition shared keys as 732 * necessary so that we can potentially authenticate the ACK 733 */ 734 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 735 if (error) 736 goto nomem_init; 737 738 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 739 * is supposed to be authenticated and we have to do delayed 740 * authentication. We've just recreated the association using 741 * the information in the cookie and now it's much easier to 742 * do the authentication. 743 */ 744 if (chunk->auth_chunk) { 745 struct sctp_chunk auth; 746 sctp_ierror_t ret; 747 748 /* set-up our fake chunk so that we can process it */ 749 auth.skb = chunk->auth_chunk; 750 auth.asoc = chunk->asoc; 751 auth.sctp_hdr = chunk->sctp_hdr; 752 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 753 sizeof(sctp_chunkhdr_t)); 754 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 755 auth.transport = chunk->transport; 756 757 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth); 758 759 /* We can now safely free the auth_chunk clone */ 760 kfree_skb(chunk->auth_chunk); 761 762 if (ret != SCTP_IERROR_NO_ERROR) { 763 sctp_association_free(new_asoc); 764 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 765 } 766 } 767 768 repl = sctp_make_cookie_ack(new_asoc, chunk); 769 if (!repl) 770 goto nomem_init; 771 772 /* RFC 2960 5.1 Normal Establishment of an Association 773 * 774 * D) IMPLEMENTATION NOTE: An implementation may choose to 775 * send the Communication Up notification to the SCTP user 776 * upon reception of a valid COOKIE ECHO chunk. 777 */ 778 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 779 new_asoc->c.sinit_num_ostreams, 780 new_asoc->c.sinit_max_instreams, 781 NULL, GFP_ATOMIC); 782 if (!ev) 783 goto nomem_ev; 784 785 /* Sockets API Draft Section 5.3.1.6 786 * When a peer sends a Adaptation Layer Indication parameter , SCTP 787 * delivers this notification to inform the application that of the 788 * peers requested adaptation layer. 789 */ 790 if (new_asoc->peer.adaptation_ind) { 791 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 792 GFP_ATOMIC); 793 if (!ai_ev) 794 goto nomem_aiev; 795 } 796 797 /* Add all the state machine commands now since we've created 798 * everything. This way we don't introduce memory corruptions 799 * during side-effect processing and correclty count established 800 * associations. 801 */ 802 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 803 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 804 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 805 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 806 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 807 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 808 809 if (new_asoc->autoclose) 810 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 811 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 812 813 /* This will send the COOKIE ACK */ 814 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 815 816 /* Queue the ASSOC_CHANGE event */ 817 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 818 819 /* Send up the Adaptation Layer Indication event */ 820 if (ai_ev) 821 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 822 SCTP_ULPEVENT(ai_ev)); 823 824 return SCTP_DISPOSITION_CONSUME; 825 826 nomem_aiev: 827 sctp_ulpevent_free(ev); 828 nomem_ev: 829 sctp_chunk_free(repl); 830 nomem_init: 831 sctp_association_free(new_asoc); 832 nomem: 833 return SCTP_DISPOSITION_NOMEM; 834 } 835 836 /* 837 * Respond to a normal COOKIE ACK chunk. 838 * We are the side that is being asked for an association. 839 * 840 * RFC 2960 5.1 Normal Establishment of an Association 841 * 842 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 843 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 844 * timer. It may also notify its ULP about the successful 845 * establishment of the association with a Communication Up 846 * notification (see Section 10). 847 * 848 * Verification Tag: 849 * Inputs 850 * (endpoint, asoc, chunk) 851 * 852 * Outputs 853 * (asoc, reply_msg, msg_up, timers, counters) 854 * 855 * The return value is the disposition of the chunk. 856 */ 857 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, 858 const struct sctp_association *asoc, 859 const sctp_subtype_t type, void *arg, 860 sctp_cmd_seq_t *commands) 861 { 862 struct sctp_chunk *chunk = arg; 863 struct sctp_ulpevent *ev; 864 865 if (!sctp_vtag_verify(chunk, asoc)) 866 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 867 868 /* Verify that the chunk length for the COOKIE-ACK is OK. 869 * If we don't do this, any bundled chunks may be junked. 870 */ 871 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 872 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 873 commands); 874 875 /* Reset init error count upon receipt of COOKIE-ACK, 876 * to avoid problems with the managemement of this 877 * counter in stale cookie situations when a transition back 878 * from the COOKIE-ECHOED state to the COOKIE-WAIT 879 * state is performed. 880 */ 881 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 882 883 /* RFC 2960 5.1 Normal Establishment of an Association 884 * 885 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 886 * from the COOKIE-ECHOED state to the ESTABLISHED state, 887 * stopping the T1-cookie timer. 888 */ 889 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 890 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 891 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 892 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 893 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 894 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); 895 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 896 if (asoc->autoclose) 897 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 898 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 899 900 /* It may also notify its ULP about the successful 901 * establishment of the association with a Communication Up 902 * notification (see Section 10). 903 */ 904 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 905 0, asoc->c.sinit_num_ostreams, 906 asoc->c.sinit_max_instreams, 907 NULL, GFP_ATOMIC); 908 909 if (!ev) 910 goto nomem; 911 912 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 913 914 /* Sockets API Draft Section 5.3.1.6 915 * When a peer sends a Adaptation Layer Indication parameter , SCTP 916 * delivers this notification to inform the application that of the 917 * peers requested adaptation layer. 918 */ 919 if (asoc->peer.adaptation_ind) { 920 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 921 if (!ev) 922 goto nomem; 923 924 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 925 SCTP_ULPEVENT(ev)); 926 } 927 928 return SCTP_DISPOSITION_CONSUME; 929 nomem: 930 return SCTP_DISPOSITION_NOMEM; 931 } 932 933 /* Generate and sendout a heartbeat packet. */ 934 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 935 const struct sctp_association *asoc, 936 const sctp_subtype_t type, 937 void *arg, 938 sctp_cmd_seq_t *commands) 939 { 940 struct sctp_transport *transport = (struct sctp_transport *) arg; 941 struct sctp_chunk *reply; 942 sctp_sender_hb_info_t hbinfo; 943 size_t paylen = 0; 944 945 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; 946 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); 947 hbinfo.daddr = transport->ipaddr; 948 hbinfo.sent_at = jiffies; 949 hbinfo.hb_nonce = transport->hb_nonce; 950 951 /* Send a heartbeat to our peer. */ 952 paylen = sizeof(sctp_sender_hb_info_t); 953 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); 954 if (!reply) 955 return SCTP_DISPOSITION_NOMEM; 956 957 /* Set rto_pending indicating that an RTT measurement 958 * is started with this heartbeat chunk. 959 */ 960 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 961 SCTP_TRANSPORT(transport)); 962 963 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 964 return SCTP_DISPOSITION_CONSUME; 965 } 966 967 /* Generate a HEARTBEAT packet on the given transport. */ 968 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 969 const struct sctp_association *asoc, 970 const sctp_subtype_t type, 971 void *arg, 972 sctp_cmd_seq_t *commands) 973 { 974 struct sctp_transport *transport = (struct sctp_transport *) arg; 975 976 if (asoc->overall_error_count >= asoc->max_retrans) { 977 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 978 SCTP_ERROR(ETIMEDOUT)); 979 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 980 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 981 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 982 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 983 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 984 return SCTP_DISPOSITION_DELETE_TCB; 985 } 986 987 /* Section 3.3.5. 988 * The Sender-specific Heartbeat Info field should normally include 989 * information about the sender's current time when this HEARTBEAT 990 * chunk is sent and the destination transport address to which this 991 * HEARTBEAT is sent (see Section 8.3). 992 */ 993 994 if (transport->param_flags & SPP_HB_ENABLE) { 995 if (SCTP_DISPOSITION_NOMEM == 996 sctp_sf_heartbeat(ep, asoc, type, arg, 997 commands)) 998 return SCTP_DISPOSITION_NOMEM; 999 1000 /* Set transport error counter and association error counter 1001 * when sending heartbeat. 1002 */ 1003 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1004 SCTP_TRANSPORT(transport)); 1005 } 1006 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1007 SCTP_TRANSPORT(transport)); 1008 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1009 SCTP_TRANSPORT(transport)); 1010 1011 return SCTP_DISPOSITION_CONSUME; 1012 } 1013 1014 /* 1015 * Process an heartbeat request. 1016 * 1017 * Section: 8.3 Path Heartbeat 1018 * The receiver of the HEARTBEAT should immediately respond with a 1019 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1020 * from the received HEARTBEAT chunk. 1021 * 1022 * Verification Tag: 8.5 Verification Tag [Normal verification] 1023 * When receiving an SCTP packet, the endpoint MUST ensure that the 1024 * value in the Verification Tag field of the received SCTP packet 1025 * matches its own Tag. If the received Verification Tag value does not 1026 * match the receiver's own tag value, the receiver shall silently 1027 * discard the packet and shall not process it any further except for 1028 * those cases listed in Section 8.5.1 below. 1029 * 1030 * Inputs 1031 * (endpoint, asoc, chunk) 1032 * 1033 * Outputs 1034 * (asoc, reply_msg, msg_up, timers, counters) 1035 * 1036 * The return value is the disposition of the chunk. 1037 */ 1038 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 1039 const struct sctp_association *asoc, 1040 const sctp_subtype_t type, 1041 void *arg, 1042 sctp_cmd_seq_t *commands) 1043 { 1044 struct sctp_chunk *chunk = arg; 1045 struct sctp_chunk *reply; 1046 size_t paylen = 0; 1047 1048 if (!sctp_vtag_verify(chunk, asoc)) 1049 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1050 1051 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1052 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1053 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1054 commands); 1055 1056 /* 8.3 The receiver of the HEARTBEAT should immediately 1057 * respond with a HEARTBEAT ACK that contains the Heartbeat 1058 * Information field copied from the received HEARTBEAT chunk. 1059 */ 1060 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1061 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1062 if (!pskb_pull(chunk->skb, paylen)) 1063 goto nomem; 1064 1065 reply = sctp_make_heartbeat_ack(asoc, chunk, 1066 chunk->subh.hb_hdr, paylen); 1067 if (!reply) 1068 goto nomem; 1069 1070 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1071 return SCTP_DISPOSITION_CONSUME; 1072 1073 nomem: 1074 return SCTP_DISPOSITION_NOMEM; 1075 } 1076 1077 /* 1078 * Process the returning HEARTBEAT ACK. 1079 * 1080 * Section: 8.3 Path Heartbeat 1081 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1082 * should clear the error counter of the destination transport 1083 * address to which the HEARTBEAT was sent, and mark the destination 1084 * transport address as active if it is not so marked. The endpoint may 1085 * optionally report to the upper layer when an inactive destination 1086 * address is marked as active due to the reception of the latest 1087 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1088 * clear the association overall error count as well (as defined 1089 * in section 8.1). 1090 * 1091 * The receiver of the HEARTBEAT ACK should also perform an RTT 1092 * measurement for that destination transport address using the time 1093 * value carried in the HEARTBEAT ACK chunk. 1094 * 1095 * Verification Tag: 8.5 Verification Tag [Normal verification] 1096 * 1097 * Inputs 1098 * (endpoint, asoc, chunk) 1099 * 1100 * Outputs 1101 * (asoc, reply_msg, msg_up, timers, counters) 1102 * 1103 * The return value is the disposition of the chunk. 1104 */ 1105 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 1106 const struct sctp_association *asoc, 1107 const sctp_subtype_t type, 1108 void *arg, 1109 sctp_cmd_seq_t *commands) 1110 { 1111 struct sctp_chunk *chunk = arg; 1112 union sctp_addr from_addr; 1113 struct sctp_transport *link; 1114 sctp_sender_hb_info_t *hbinfo; 1115 unsigned long max_interval; 1116 1117 if (!sctp_vtag_verify(chunk, asoc)) 1118 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1119 1120 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1121 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1122 sizeof(sctp_sender_hb_info_t))) 1123 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1124 commands); 1125 1126 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1127 /* Make sure that the length of the parameter is what we expect */ 1128 if (ntohs(hbinfo->param_hdr.length) != 1129 sizeof(sctp_sender_hb_info_t)) { 1130 return SCTP_DISPOSITION_DISCARD; 1131 } 1132 1133 from_addr = hbinfo->daddr; 1134 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1135 1136 /* This should never happen, but lets log it if so. */ 1137 if (unlikely(!link)) { 1138 if (from_addr.sa.sa_family == AF_INET6) { 1139 if (net_ratelimit()) 1140 printk(KERN_WARNING 1141 "%s association %p could not find address %pI6\n", 1142 __func__, 1143 asoc, 1144 &from_addr.v6.sin6_addr); 1145 } else { 1146 if (net_ratelimit()) 1147 printk(KERN_WARNING 1148 "%s association %p could not find address %pI4\n", 1149 __func__, 1150 asoc, 1151 &from_addr.v4.sin_addr.s_addr); 1152 } 1153 return SCTP_DISPOSITION_DISCARD; 1154 } 1155 1156 /* Validate the 64-bit random nonce. */ 1157 if (hbinfo->hb_nonce != link->hb_nonce) 1158 return SCTP_DISPOSITION_DISCARD; 1159 1160 max_interval = link->hbinterval + link->rto; 1161 1162 /* Check if the timestamp looks valid. */ 1163 if (time_after(hbinfo->sent_at, jiffies) || 1164 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1165 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp " 1166 "received for transport: %p\n", 1167 __func__, link); 1168 return SCTP_DISPOSITION_DISCARD; 1169 } 1170 1171 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1172 * the HEARTBEAT should clear the error counter of the 1173 * destination transport address to which the HEARTBEAT was 1174 * sent and mark the destination transport address as active if 1175 * it is not so marked. 1176 */ 1177 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1178 1179 return SCTP_DISPOSITION_CONSUME; 1180 } 1181 1182 /* Helper function to send out an abort for the restart 1183 * condition. 1184 */ 1185 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1186 struct sctp_chunk *init, 1187 sctp_cmd_seq_t *commands) 1188 { 1189 int len; 1190 struct sctp_packet *pkt; 1191 union sctp_addr_param *addrparm; 1192 struct sctp_errhdr *errhdr; 1193 struct sctp_endpoint *ep; 1194 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1195 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1196 1197 /* Build the error on the stack. We are way to malloc crazy 1198 * throughout the code today. 1199 */ 1200 errhdr = (struct sctp_errhdr *)buffer; 1201 addrparm = (union sctp_addr_param *)errhdr->variable; 1202 1203 /* Copy into a parm format. */ 1204 len = af->to_addr_param(ssa, addrparm); 1205 len += sizeof(sctp_errhdr_t); 1206 1207 errhdr->cause = SCTP_ERROR_RESTART; 1208 errhdr->length = htons(len); 1209 1210 /* Assign to the control socket. */ 1211 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1212 1213 /* Association is NULL since this may be a restart attack and we 1214 * want to send back the attacker's vtag. 1215 */ 1216 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1217 1218 if (!pkt) 1219 goto out; 1220 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1221 1222 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1223 1224 /* Discard the rest of the inbound packet. */ 1225 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1226 1227 out: 1228 /* Even if there is no memory, treat as a failure so 1229 * the packet will get dropped. 1230 */ 1231 return 0; 1232 } 1233 1234 /* A restart is occurring, check to make sure no new addresses 1235 * are being added as we may be under a takeover attack. 1236 */ 1237 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1238 const struct sctp_association *asoc, 1239 struct sctp_chunk *init, 1240 sctp_cmd_seq_t *commands) 1241 { 1242 struct sctp_transport *new_addr, *addr; 1243 int found; 1244 1245 /* Implementor's Guide - Sectin 5.2.2 1246 * ... 1247 * Before responding the endpoint MUST check to see if the 1248 * unexpected INIT adds new addresses to the association. If new 1249 * addresses are added to the association, the endpoint MUST respond 1250 * with an ABORT.. 1251 */ 1252 1253 /* Search through all current addresses and make sure 1254 * we aren't adding any new ones. 1255 */ 1256 new_addr = NULL; 1257 found = 0; 1258 1259 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1260 transports) { 1261 found = 0; 1262 list_for_each_entry(addr, &asoc->peer.transport_addr_list, 1263 transports) { 1264 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1265 &addr->ipaddr)) { 1266 found = 1; 1267 break; 1268 } 1269 } 1270 if (!found) 1271 break; 1272 } 1273 1274 /* If a new address was added, ABORT the sender. */ 1275 if (!found && new_addr) { 1276 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1277 } 1278 1279 /* Return success if all addresses were found. */ 1280 return found; 1281 } 1282 1283 /* Populate the verification/tie tags based on overlapping INIT 1284 * scenario. 1285 * 1286 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1287 */ 1288 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1289 const struct sctp_association *asoc) 1290 { 1291 switch (asoc->state) { 1292 1293 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1294 1295 case SCTP_STATE_COOKIE_WAIT: 1296 new_asoc->c.my_vtag = asoc->c.my_vtag; 1297 new_asoc->c.my_ttag = asoc->c.my_vtag; 1298 new_asoc->c.peer_ttag = 0; 1299 break; 1300 1301 case SCTP_STATE_COOKIE_ECHOED: 1302 new_asoc->c.my_vtag = asoc->c.my_vtag; 1303 new_asoc->c.my_ttag = asoc->c.my_vtag; 1304 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1305 break; 1306 1307 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1308 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1309 */ 1310 default: 1311 new_asoc->c.my_ttag = asoc->c.my_vtag; 1312 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1313 break; 1314 } 1315 1316 /* Other parameters for the endpoint SHOULD be copied from the 1317 * existing parameters of the association (e.g. number of 1318 * outbound streams) into the INIT ACK and cookie. 1319 */ 1320 new_asoc->rwnd = asoc->rwnd; 1321 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1322 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1323 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1324 } 1325 1326 /* 1327 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1328 * handling action. 1329 * 1330 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1331 * 1332 * Returns value representing action to be taken. These action values 1333 * correspond to Action/Description values in RFC 2960, Table 2. 1334 */ 1335 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1336 const struct sctp_association *asoc) 1337 { 1338 /* In this case, the peer may have restarted. */ 1339 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1340 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1341 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1342 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1343 return 'A'; 1344 1345 /* Collision case B. */ 1346 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1347 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1348 (0 == asoc->c.peer_vtag))) { 1349 return 'B'; 1350 } 1351 1352 /* Collision case D. */ 1353 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1354 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1355 return 'D'; 1356 1357 /* Collision case C. */ 1358 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1359 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1360 (0 == new_asoc->c.my_ttag) && 1361 (0 == new_asoc->c.peer_ttag)) 1362 return 'C'; 1363 1364 /* No match to any of the special cases; discard this packet. */ 1365 return 'E'; 1366 } 1367 1368 /* Common helper routine for both duplicate and simulataneous INIT 1369 * chunk handling. 1370 */ 1371 static sctp_disposition_t sctp_sf_do_unexpected_init( 1372 const struct sctp_endpoint *ep, 1373 const struct sctp_association *asoc, 1374 const sctp_subtype_t type, 1375 void *arg, sctp_cmd_seq_t *commands) 1376 { 1377 sctp_disposition_t retval; 1378 struct sctp_chunk *chunk = arg; 1379 struct sctp_chunk *repl; 1380 struct sctp_association *new_asoc; 1381 struct sctp_chunk *err_chunk; 1382 struct sctp_packet *packet; 1383 sctp_unrecognized_param_t *unk_param; 1384 int len; 1385 1386 /* 6.10 Bundling 1387 * An endpoint MUST NOT bundle INIT, INIT ACK or 1388 * SHUTDOWN COMPLETE with any other chunks. 1389 * 1390 * IG Section 2.11.2 1391 * Furthermore, we require that the receiver of an INIT chunk MUST 1392 * enforce these rules by silently discarding an arriving packet 1393 * with an INIT chunk that is bundled with other chunks. 1394 */ 1395 if (!chunk->singleton) 1396 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1397 1398 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1399 * Tag. 1400 */ 1401 if (chunk->sctp_hdr->vtag != 0) 1402 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1403 1404 /* Make sure that the INIT chunk has a valid length. 1405 * In this case, we generate a protocol violation since we have 1406 * an association established. 1407 */ 1408 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1409 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1410 commands); 1411 /* Grab the INIT header. */ 1412 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1413 1414 /* Tag the variable length parameters. */ 1415 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1416 1417 /* Verify the INIT chunk before processing it. */ 1418 err_chunk = NULL; 1419 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1420 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1421 &err_chunk)) { 1422 /* This chunk contains fatal error. It is to be discarded. 1423 * Send an ABORT, with causes if there is any. 1424 */ 1425 if (err_chunk) { 1426 packet = sctp_abort_pkt_new(ep, asoc, arg, 1427 (__u8 *)(err_chunk->chunk_hdr) + 1428 sizeof(sctp_chunkhdr_t), 1429 ntohs(err_chunk->chunk_hdr->length) - 1430 sizeof(sctp_chunkhdr_t)); 1431 1432 if (packet) { 1433 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1434 SCTP_PACKET(packet)); 1435 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1436 retval = SCTP_DISPOSITION_CONSUME; 1437 } else { 1438 retval = SCTP_DISPOSITION_NOMEM; 1439 } 1440 goto cleanup; 1441 } else { 1442 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1443 commands); 1444 } 1445 } 1446 1447 /* 1448 * Other parameters for the endpoint SHOULD be copied from the 1449 * existing parameters of the association (e.g. number of 1450 * outbound streams) into the INIT ACK and cookie. 1451 * FIXME: We are copying parameters from the endpoint not the 1452 * association. 1453 */ 1454 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1455 if (!new_asoc) 1456 goto nomem; 1457 1458 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1459 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1460 goto nomem; 1461 1462 /* In the outbound INIT ACK the endpoint MUST copy its current 1463 * Verification Tag and Peers Verification tag into a reserved 1464 * place (local tie-tag and per tie-tag) within the state cookie. 1465 */ 1466 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1467 sctp_source(chunk), 1468 (sctp_init_chunk_t *)chunk->chunk_hdr, 1469 GFP_ATOMIC)) 1470 goto nomem; 1471 1472 /* Make sure no new addresses are being added during the 1473 * restart. Do not do this check for COOKIE-WAIT state, 1474 * since there are no peer addresses to check against. 1475 * Upon return an ABORT will have been sent if needed. 1476 */ 1477 if (!sctp_state(asoc, COOKIE_WAIT)) { 1478 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1479 commands)) { 1480 retval = SCTP_DISPOSITION_CONSUME; 1481 goto nomem_retval; 1482 } 1483 } 1484 1485 sctp_tietags_populate(new_asoc, asoc); 1486 1487 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1488 1489 /* If there are errors need to be reported for unknown parameters, 1490 * make sure to reserve enough room in the INIT ACK for them. 1491 */ 1492 len = 0; 1493 if (err_chunk) { 1494 len = ntohs(err_chunk->chunk_hdr->length) - 1495 sizeof(sctp_chunkhdr_t); 1496 } 1497 1498 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1499 if (!repl) 1500 goto nomem; 1501 1502 /* If there are errors need to be reported for unknown parameters, 1503 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1504 * parameter. 1505 */ 1506 if (err_chunk) { 1507 /* Get the "Unrecognized parameter" parameter(s) out of the 1508 * ERROR chunk generated by sctp_verify_init(). Since the 1509 * error cause code for "unknown parameter" and the 1510 * "Unrecognized parameter" type is the same, we can 1511 * construct the parameters in INIT ACK by copying the 1512 * ERROR causes over. 1513 */ 1514 unk_param = (sctp_unrecognized_param_t *) 1515 ((__u8 *)(err_chunk->chunk_hdr) + 1516 sizeof(sctp_chunkhdr_t)); 1517 /* Replace the cause code with the "Unrecognized parameter" 1518 * parameter type. 1519 */ 1520 sctp_addto_chunk(repl, len, unk_param); 1521 } 1522 1523 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1524 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1525 1526 /* 1527 * Note: After sending out INIT ACK with the State Cookie parameter, 1528 * "Z" MUST NOT allocate any resources for this new association. 1529 * Otherwise, "Z" will be vulnerable to resource attacks. 1530 */ 1531 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1532 retval = SCTP_DISPOSITION_CONSUME; 1533 1534 return retval; 1535 1536 nomem: 1537 retval = SCTP_DISPOSITION_NOMEM; 1538 nomem_retval: 1539 if (new_asoc) 1540 sctp_association_free(new_asoc); 1541 cleanup: 1542 if (err_chunk) 1543 sctp_chunk_free(err_chunk); 1544 return retval; 1545 } 1546 1547 /* 1548 * Handle simultanous INIT. 1549 * This means we started an INIT and then we got an INIT request from 1550 * our peer. 1551 * 1552 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1553 * This usually indicates an initialization collision, i.e., each 1554 * endpoint is attempting, at about the same time, to establish an 1555 * association with the other endpoint. 1556 * 1557 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1558 * endpoint MUST respond with an INIT ACK using the same parameters it 1559 * sent in its original INIT chunk (including its Verification Tag, 1560 * unchanged). These original parameters are combined with those from the 1561 * newly received INIT chunk. The endpoint shall also generate a State 1562 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1563 * INIT to calculate the State Cookie. 1564 * 1565 * After that, the endpoint MUST NOT change its state, the T1-init 1566 * timer shall be left running and the corresponding TCB MUST NOT be 1567 * destroyed. The normal procedures for handling State Cookies when 1568 * a TCB exists will resolve the duplicate INITs to a single association. 1569 * 1570 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1571 * its Tie-Tags with the Tag information of itself and its peer (see 1572 * section 5.2.2 for a description of the Tie-Tags). 1573 * 1574 * Verification Tag: Not explicit, but an INIT can not have a valid 1575 * verification tag, so we skip the check. 1576 * 1577 * Inputs 1578 * (endpoint, asoc, chunk) 1579 * 1580 * Outputs 1581 * (asoc, reply_msg, msg_up, timers, counters) 1582 * 1583 * The return value is the disposition of the chunk. 1584 */ 1585 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1586 const struct sctp_association *asoc, 1587 const sctp_subtype_t type, 1588 void *arg, 1589 sctp_cmd_seq_t *commands) 1590 { 1591 /* Call helper to do the real work for both simulataneous and 1592 * duplicate INIT chunk handling. 1593 */ 1594 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1595 } 1596 1597 /* 1598 * Handle duplicated INIT messages. These are usually delayed 1599 * restransmissions. 1600 * 1601 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1602 * COOKIE-ECHOED and COOKIE-WAIT 1603 * 1604 * Unless otherwise stated, upon reception of an unexpected INIT for 1605 * this association, the endpoint shall generate an INIT ACK with a 1606 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1607 * current Verification Tag and peer's Verification Tag into a reserved 1608 * place within the state cookie. We shall refer to these locations as 1609 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1610 * containing this INIT ACK MUST carry a Verification Tag value equal to 1611 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1612 * MUST contain a new Initiation Tag (randomly generated see Section 1613 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1614 * existing parameters of the association (e.g. number of outbound 1615 * streams) into the INIT ACK and cookie. 1616 * 1617 * After sending out the INIT ACK, the endpoint shall take no further 1618 * actions, i.e., the existing association, including its current state, 1619 * and the corresponding TCB MUST NOT be changed. 1620 * 1621 * Note: Only when a TCB exists and the association is not in a COOKIE- 1622 * WAIT state are the Tie-Tags populated. For a normal association INIT 1623 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1624 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1625 * State Cookie are populated as specified in section 5.2.1. 1626 * 1627 * Verification Tag: Not specified, but an INIT has no way of knowing 1628 * what the verification tag could be, so we ignore it. 1629 * 1630 * Inputs 1631 * (endpoint, asoc, chunk) 1632 * 1633 * Outputs 1634 * (asoc, reply_msg, msg_up, timers, counters) 1635 * 1636 * The return value is the disposition of the chunk. 1637 */ 1638 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1639 const struct sctp_association *asoc, 1640 const sctp_subtype_t type, 1641 void *arg, 1642 sctp_cmd_seq_t *commands) 1643 { 1644 /* Call helper to do the real work for both simulataneous and 1645 * duplicate INIT chunk handling. 1646 */ 1647 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1648 } 1649 1650 1651 /* 1652 * Unexpected INIT-ACK handler. 1653 * 1654 * Section 5.2.3 1655 * If an INIT ACK received by an endpoint in any state other than the 1656 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1657 * An unexpected INIT ACK usually indicates the processing of an old or 1658 * duplicated INIT chunk. 1659 */ 1660 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep, 1661 const struct sctp_association *asoc, 1662 const sctp_subtype_t type, 1663 void *arg, sctp_cmd_seq_t *commands) 1664 { 1665 /* Per the above section, we'll discard the chunk if we have an 1666 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1667 */ 1668 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 1669 return sctp_sf_ootb(ep, asoc, type, arg, commands); 1670 else 1671 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 1672 } 1673 1674 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1675 * 1676 * Section 5.2.4 1677 * A) In this case, the peer may have restarted. 1678 */ 1679 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1680 const struct sctp_association *asoc, 1681 struct sctp_chunk *chunk, 1682 sctp_cmd_seq_t *commands, 1683 struct sctp_association *new_asoc) 1684 { 1685 sctp_init_chunk_t *peer_init; 1686 struct sctp_ulpevent *ev; 1687 struct sctp_chunk *repl; 1688 struct sctp_chunk *err; 1689 sctp_disposition_t disposition; 1690 1691 /* new_asoc is a brand-new association, so these are not yet 1692 * side effects--it is safe to run them here. 1693 */ 1694 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1695 1696 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1697 sctp_source(chunk), peer_init, 1698 GFP_ATOMIC)) 1699 goto nomem; 1700 1701 /* Make sure no new addresses are being added during the 1702 * restart. Though this is a pretty complicated attack 1703 * since you'd have to get inside the cookie. 1704 */ 1705 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1706 return SCTP_DISPOSITION_CONSUME; 1707 } 1708 1709 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1710 * the peer has restarted (Action A), it MUST NOT setup a new 1711 * association but instead resend the SHUTDOWN ACK and send an ERROR 1712 * chunk with a "Cookie Received while Shutting Down" error cause to 1713 * its peer. 1714 */ 1715 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1716 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1717 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1718 chunk, commands); 1719 if (SCTP_DISPOSITION_NOMEM == disposition) 1720 goto nomem; 1721 1722 err = sctp_make_op_error(asoc, chunk, 1723 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1724 NULL, 0, 0); 1725 if (err) 1726 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1727 SCTP_CHUNK(err)); 1728 1729 return SCTP_DISPOSITION_CONSUME; 1730 } 1731 1732 /* For now, fail any unsent/unacked data. Consider the optional 1733 * choice of resending of this data. 1734 */ 1735 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1736 1737 repl = sctp_make_cookie_ack(new_asoc, chunk); 1738 if (!repl) 1739 goto nomem; 1740 1741 /* Report association restart to upper layer. */ 1742 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1743 new_asoc->c.sinit_num_ostreams, 1744 new_asoc->c.sinit_max_instreams, 1745 NULL, GFP_ATOMIC); 1746 if (!ev) 1747 goto nomem_ev; 1748 1749 /* Update the content of current association. */ 1750 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1751 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1752 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1753 return SCTP_DISPOSITION_CONSUME; 1754 1755 nomem_ev: 1756 sctp_chunk_free(repl); 1757 nomem: 1758 return SCTP_DISPOSITION_NOMEM; 1759 } 1760 1761 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1762 * 1763 * Section 5.2.4 1764 * B) In this case, both sides may be attempting to start an association 1765 * at about the same time but the peer endpoint started its INIT 1766 * after responding to the local endpoint's INIT 1767 */ 1768 /* This case represents an initialization collision. */ 1769 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1770 const struct sctp_association *asoc, 1771 struct sctp_chunk *chunk, 1772 sctp_cmd_seq_t *commands, 1773 struct sctp_association *new_asoc) 1774 { 1775 sctp_init_chunk_t *peer_init; 1776 struct sctp_chunk *repl; 1777 1778 /* new_asoc is a brand-new association, so these are not yet 1779 * side effects--it is safe to run them here. 1780 */ 1781 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1782 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1783 sctp_source(chunk), peer_init, 1784 GFP_ATOMIC)) 1785 goto nomem; 1786 1787 /* Update the content of current association. */ 1788 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1789 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1790 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1791 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1792 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1793 1794 repl = sctp_make_cookie_ack(new_asoc, chunk); 1795 if (!repl) 1796 goto nomem; 1797 1798 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1799 1800 /* RFC 2960 5.1 Normal Establishment of an Association 1801 * 1802 * D) IMPLEMENTATION NOTE: An implementation may choose to 1803 * send the Communication Up notification to the SCTP user 1804 * upon reception of a valid COOKIE ECHO chunk. 1805 * 1806 * Sadly, this needs to be implemented as a side-effect, because 1807 * we are not guaranteed to have set the association id of the real 1808 * association and so these notifications need to be delayed until 1809 * the association id is allocated. 1810 */ 1811 1812 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1813 1814 /* Sockets API Draft Section 5.3.1.6 1815 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1816 * delivers this notification to inform the application that of the 1817 * peers requested adaptation layer. 1818 * 1819 * This also needs to be done as a side effect for the same reason as 1820 * above. 1821 */ 1822 if (asoc->peer.adaptation_ind) 1823 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1824 1825 return SCTP_DISPOSITION_CONSUME; 1826 1827 nomem: 1828 return SCTP_DISPOSITION_NOMEM; 1829 } 1830 1831 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1832 * 1833 * Section 5.2.4 1834 * C) In this case, the local endpoint's cookie has arrived late. 1835 * Before it arrived, the local endpoint sent an INIT and received an 1836 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1837 * but a new tag of its own. 1838 */ 1839 /* This case represents an initialization collision. */ 1840 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1841 const struct sctp_association *asoc, 1842 struct sctp_chunk *chunk, 1843 sctp_cmd_seq_t *commands, 1844 struct sctp_association *new_asoc) 1845 { 1846 /* The cookie should be silently discarded. 1847 * The endpoint SHOULD NOT change states and should leave 1848 * any timers running. 1849 */ 1850 return SCTP_DISPOSITION_DISCARD; 1851 } 1852 1853 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1854 * 1855 * Section 5.2.4 1856 * 1857 * D) When both local and remote tags match the endpoint should always 1858 * enter the ESTABLISHED state, if it has not already done so. 1859 */ 1860 /* This case represents an initialization collision. */ 1861 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1862 const struct sctp_association *asoc, 1863 struct sctp_chunk *chunk, 1864 sctp_cmd_seq_t *commands, 1865 struct sctp_association *new_asoc) 1866 { 1867 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1868 struct sctp_chunk *repl; 1869 1870 /* Clarification from Implementor's Guide: 1871 * D) When both local and remote tags match the endpoint should 1872 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1873 * It should stop any cookie timer that may be running and send 1874 * a COOKIE ACK. 1875 */ 1876 1877 /* Don't accidentally move back into established state. */ 1878 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1879 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1880 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1881 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1882 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1883 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1884 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1885 SCTP_NULL()); 1886 1887 /* RFC 2960 5.1 Normal Establishment of an Association 1888 * 1889 * D) IMPLEMENTATION NOTE: An implementation may choose 1890 * to send the Communication Up notification to the 1891 * SCTP user upon reception of a valid COOKIE 1892 * ECHO chunk. 1893 */ 1894 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1895 SCTP_COMM_UP, 0, 1896 asoc->c.sinit_num_ostreams, 1897 asoc->c.sinit_max_instreams, 1898 NULL, GFP_ATOMIC); 1899 if (!ev) 1900 goto nomem; 1901 1902 /* Sockets API Draft Section 5.3.1.6 1903 * When a peer sends a Adaptation Layer Indication parameter, 1904 * SCTP delivers this notification to inform the application 1905 * that of the peers requested adaptation layer. 1906 */ 1907 if (asoc->peer.adaptation_ind) { 1908 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1909 GFP_ATOMIC); 1910 if (!ai_ev) 1911 goto nomem; 1912 1913 } 1914 } 1915 1916 repl = sctp_make_cookie_ack(new_asoc, chunk); 1917 if (!repl) 1918 goto nomem; 1919 1920 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1921 1922 if (ev) 1923 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1924 SCTP_ULPEVENT(ev)); 1925 if (ai_ev) 1926 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1927 SCTP_ULPEVENT(ai_ev)); 1928 1929 return SCTP_DISPOSITION_CONSUME; 1930 1931 nomem: 1932 if (ai_ev) 1933 sctp_ulpevent_free(ai_ev); 1934 if (ev) 1935 sctp_ulpevent_free(ev); 1936 return SCTP_DISPOSITION_NOMEM; 1937 } 1938 1939 /* 1940 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1941 * chunk was retransmitted and then delayed in the network. 1942 * 1943 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1944 * 1945 * Verification Tag: None. Do cookie validation. 1946 * 1947 * Inputs 1948 * (endpoint, asoc, chunk) 1949 * 1950 * Outputs 1951 * (asoc, reply_msg, msg_up, timers, counters) 1952 * 1953 * The return value is the disposition of the chunk. 1954 */ 1955 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1956 const struct sctp_association *asoc, 1957 const sctp_subtype_t type, 1958 void *arg, 1959 sctp_cmd_seq_t *commands) 1960 { 1961 sctp_disposition_t retval; 1962 struct sctp_chunk *chunk = arg; 1963 struct sctp_association *new_asoc; 1964 int error = 0; 1965 char action; 1966 struct sctp_chunk *err_chk_p; 1967 1968 /* Make sure that the chunk has a valid length from the protocol 1969 * perspective. In this case check to make sure we have at least 1970 * enough for the chunk header. Cookie length verification is 1971 * done later. 1972 */ 1973 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1974 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1975 commands); 1976 1977 /* "Decode" the chunk. We have no optional parameters so we 1978 * are in good shape. 1979 */ 1980 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1981 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1982 sizeof(sctp_chunkhdr_t))) 1983 goto nomem; 1984 1985 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1986 * of a duplicate COOKIE ECHO match the Verification Tags of the 1987 * current association, consider the State Cookie valid even if 1988 * the lifespan is exceeded. 1989 */ 1990 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1991 &err_chk_p); 1992 1993 /* FIXME: 1994 * If the re-build failed, what is the proper error path 1995 * from here? 1996 * 1997 * [We should abort the association. --piggy] 1998 */ 1999 if (!new_asoc) { 2000 /* FIXME: Several errors are possible. A bad cookie should 2001 * be silently discarded, but think about logging it too. 2002 */ 2003 switch (error) { 2004 case -SCTP_IERROR_NOMEM: 2005 goto nomem; 2006 2007 case -SCTP_IERROR_STALE_COOKIE: 2008 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 2009 err_chk_p); 2010 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2011 case -SCTP_IERROR_BAD_SIG: 2012 default: 2013 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2014 } 2015 } 2016 2017 /* Compare the tie_tag in cookie with the verification tag of 2018 * current association. 2019 */ 2020 action = sctp_tietags_compare(new_asoc, asoc); 2021 2022 switch (action) { 2023 case 'A': /* Association restart. */ 2024 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 2025 new_asoc); 2026 break; 2027 2028 case 'B': /* Collision case B. */ 2029 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 2030 new_asoc); 2031 break; 2032 2033 case 'C': /* Collision case C. */ 2034 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 2035 new_asoc); 2036 break; 2037 2038 case 'D': /* Collision case D. */ 2039 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 2040 new_asoc); 2041 break; 2042 2043 default: /* Discard packet for all others. */ 2044 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2045 break; 2046 } 2047 2048 /* Delete the tempory new association. */ 2049 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2050 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2051 2052 return retval; 2053 2054 nomem: 2055 return SCTP_DISPOSITION_NOMEM; 2056 } 2057 2058 /* 2059 * Process an ABORT. (SHUTDOWN-PENDING state) 2060 * 2061 * See sctp_sf_do_9_1_abort(). 2062 */ 2063 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2064 const struct sctp_endpoint *ep, 2065 const struct sctp_association *asoc, 2066 const sctp_subtype_t type, 2067 void *arg, 2068 sctp_cmd_seq_t *commands) 2069 { 2070 struct sctp_chunk *chunk = arg; 2071 2072 if (!sctp_vtag_verify_either(chunk, asoc)) 2073 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2074 2075 /* Make sure that the ABORT chunk has a valid length. 2076 * Since this is an ABORT chunk, we have to discard it 2077 * because of the following text: 2078 * RFC 2960, Section 3.3.7 2079 * If an endpoint receives an ABORT with a format error or for an 2080 * association that doesn't exist, it MUST silently discard it. 2081 * Becasue the length is "invalid", we can't really discard just 2082 * as we do not know its true length. So, to be safe, discard the 2083 * packet. 2084 */ 2085 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2086 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2087 2088 /* ADD-IP: Special case for ABORT chunks 2089 * F4) One special consideration is that ABORT Chunks arriving 2090 * destined to the IP address being deleted MUST be 2091 * ignored (see Section 5.3.1 for further details). 2092 */ 2093 if (SCTP_ADDR_DEL == 2094 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2095 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2096 2097 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2098 } 2099 2100 /* 2101 * Process an ABORT. (SHUTDOWN-SENT state) 2102 * 2103 * See sctp_sf_do_9_1_abort(). 2104 */ 2105 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 2106 const struct sctp_association *asoc, 2107 const sctp_subtype_t type, 2108 void *arg, 2109 sctp_cmd_seq_t *commands) 2110 { 2111 struct sctp_chunk *chunk = arg; 2112 2113 if (!sctp_vtag_verify_either(chunk, asoc)) 2114 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2115 2116 /* Make sure that the ABORT chunk has a valid length. 2117 * Since this is an ABORT chunk, we have to discard it 2118 * because of the following text: 2119 * RFC 2960, Section 3.3.7 2120 * If an endpoint receives an ABORT with a format error or for an 2121 * association that doesn't exist, it MUST silently discard it. 2122 * Becasue the length is "invalid", we can't really discard just 2123 * as we do not know its true length. So, to be safe, discard the 2124 * packet. 2125 */ 2126 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2127 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2128 2129 /* ADD-IP: Special case for ABORT chunks 2130 * F4) One special consideration is that ABORT Chunks arriving 2131 * destined to the IP address being deleted MUST be 2132 * ignored (see Section 5.3.1 for further details). 2133 */ 2134 if (SCTP_ADDR_DEL == 2135 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2136 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2137 2138 /* Stop the T2-shutdown timer. */ 2139 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2140 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2141 2142 /* Stop the T5-shutdown guard timer. */ 2143 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2144 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2145 2146 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2147 } 2148 2149 /* 2150 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2151 * 2152 * See sctp_sf_do_9_1_abort(). 2153 */ 2154 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2155 const struct sctp_endpoint *ep, 2156 const struct sctp_association *asoc, 2157 const sctp_subtype_t type, 2158 void *arg, 2159 sctp_cmd_seq_t *commands) 2160 { 2161 /* The same T2 timer, so we should be able to use 2162 * common function with the SHUTDOWN-SENT state. 2163 */ 2164 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2165 } 2166 2167 /* 2168 * Handle an Error received in COOKIE_ECHOED state. 2169 * 2170 * Only handle the error type of stale COOKIE Error, the other errors will 2171 * be ignored. 2172 * 2173 * Inputs 2174 * (endpoint, asoc, chunk) 2175 * 2176 * Outputs 2177 * (asoc, reply_msg, msg_up, timers, counters) 2178 * 2179 * The return value is the disposition of the chunk. 2180 */ 2181 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2182 const struct sctp_association *asoc, 2183 const sctp_subtype_t type, 2184 void *arg, 2185 sctp_cmd_seq_t *commands) 2186 { 2187 struct sctp_chunk *chunk = arg; 2188 sctp_errhdr_t *err; 2189 2190 if (!sctp_vtag_verify(chunk, asoc)) 2191 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2192 2193 /* Make sure that the ERROR chunk has a valid length. 2194 * The parameter walking depends on this as well. 2195 */ 2196 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2197 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2198 commands); 2199 2200 /* Process the error here */ 2201 /* FUTURE FIXME: When PR-SCTP related and other optional 2202 * parms are emitted, this will have to change to handle multiple 2203 * errors. 2204 */ 2205 sctp_walk_errors(err, chunk->chunk_hdr) { 2206 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2207 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2208 arg, commands); 2209 } 2210 2211 /* It is possible to have malformed error causes, and that 2212 * will cause us to end the walk early. However, since 2213 * we are discarding the packet, there should be no adverse 2214 * affects. 2215 */ 2216 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2217 } 2218 2219 /* 2220 * Handle a Stale COOKIE Error 2221 * 2222 * Section: 5.2.6 Handle Stale COOKIE Error 2223 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2224 * one of the following three alternatives. 2225 * ... 2226 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2227 * Preservative parameter requesting an extension to the lifetime of 2228 * the State Cookie. When calculating the time extension, an 2229 * implementation SHOULD use the RTT information measured based on the 2230 * previous COOKIE ECHO / ERROR exchange, and should add no more 2231 * than 1 second beyond the measured RTT, due to long State Cookie 2232 * lifetimes making the endpoint more subject to a replay attack. 2233 * 2234 * Verification Tag: Not explicit, but safe to ignore. 2235 * 2236 * Inputs 2237 * (endpoint, asoc, chunk) 2238 * 2239 * Outputs 2240 * (asoc, reply_msg, msg_up, timers, counters) 2241 * 2242 * The return value is the disposition of the chunk. 2243 */ 2244 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2245 const struct sctp_association *asoc, 2246 const sctp_subtype_t type, 2247 void *arg, 2248 sctp_cmd_seq_t *commands) 2249 { 2250 struct sctp_chunk *chunk = arg; 2251 time_t stale; 2252 sctp_cookie_preserve_param_t bht; 2253 sctp_errhdr_t *err; 2254 struct sctp_chunk *reply; 2255 struct sctp_bind_addr *bp; 2256 int attempts = asoc->init_err_counter + 1; 2257 2258 if (attempts > asoc->max_init_attempts) { 2259 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2260 SCTP_ERROR(ETIMEDOUT)); 2261 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2262 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2263 return SCTP_DISPOSITION_DELETE_TCB; 2264 } 2265 2266 err = (sctp_errhdr_t *)(chunk->skb->data); 2267 2268 /* When calculating the time extension, an implementation 2269 * SHOULD use the RTT information measured based on the 2270 * previous COOKIE ECHO / ERROR exchange, and should add no 2271 * more than 1 second beyond the measured RTT, due to long 2272 * State Cookie lifetimes making the endpoint more subject to 2273 * a replay attack. 2274 * Measure of Staleness's unit is usec. (1/1000000 sec) 2275 * Suggested Cookie Life-span Increment's unit is msec. 2276 * (1/1000 sec) 2277 * In general, if you use the suggested cookie life, the value 2278 * found in the field of measure of staleness should be doubled 2279 * to give ample time to retransmit the new cookie and thus 2280 * yield a higher probability of success on the reattempt. 2281 */ 2282 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2283 stale = (stale * 2) / 1000; 2284 2285 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2286 bht.param_hdr.length = htons(sizeof(bht)); 2287 bht.lifespan_increment = htonl(stale); 2288 2289 /* Build that new INIT chunk. */ 2290 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2291 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2292 if (!reply) 2293 goto nomem; 2294 2295 sctp_addto_chunk(reply, sizeof(bht), &bht); 2296 2297 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2298 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2299 2300 /* Stop pending T3-rtx and heartbeat timers */ 2301 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2302 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2303 2304 /* Delete non-primary peer ip addresses since we are transitioning 2305 * back to the COOKIE-WAIT state 2306 */ 2307 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2308 2309 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2310 * resend 2311 */ 2312 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2313 SCTP_TRANSPORT(asoc->peer.primary_path)); 2314 2315 /* Cast away the const modifier, as we want to just 2316 * rerun it through as a sideffect. 2317 */ 2318 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2319 2320 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2321 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2322 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2323 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2324 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2325 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2326 2327 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2328 2329 return SCTP_DISPOSITION_CONSUME; 2330 2331 nomem: 2332 return SCTP_DISPOSITION_NOMEM; 2333 } 2334 2335 /* 2336 * Process an ABORT. 2337 * 2338 * Section: 9.1 2339 * After checking the Verification Tag, the receiving endpoint shall 2340 * remove the association from its record, and shall report the 2341 * termination to its upper layer. 2342 * 2343 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2344 * B) Rules for packet carrying ABORT: 2345 * 2346 * - The endpoint shall always fill in the Verification Tag field of the 2347 * outbound packet with the destination endpoint's tag value if it 2348 * is known. 2349 * 2350 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2351 * MUST follow the procedure described in Section 8.4. 2352 * 2353 * - The receiver MUST accept the packet if the Verification Tag 2354 * matches either its own tag, OR the tag of its peer. Otherwise, the 2355 * receiver MUST silently discard the packet and take no further 2356 * action. 2357 * 2358 * Inputs 2359 * (endpoint, asoc, chunk) 2360 * 2361 * Outputs 2362 * (asoc, reply_msg, msg_up, timers, counters) 2363 * 2364 * The return value is the disposition of the chunk. 2365 */ 2366 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2367 const struct sctp_association *asoc, 2368 const sctp_subtype_t type, 2369 void *arg, 2370 sctp_cmd_seq_t *commands) 2371 { 2372 struct sctp_chunk *chunk = arg; 2373 2374 if (!sctp_vtag_verify_either(chunk, asoc)) 2375 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2376 2377 /* Make sure that the ABORT chunk has a valid length. 2378 * Since this is an ABORT chunk, we have to discard it 2379 * because of the following text: 2380 * RFC 2960, Section 3.3.7 2381 * If an endpoint receives an ABORT with a format error or for an 2382 * association that doesn't exist, it MUST silently discard it. 2383 * Becasue the length is "invalid", we can't really discard just 2384 * as we do not know its true length. So, to be safe, discard the 2385 * packet. 2386 */ 2387 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2388 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2389 2390 /* ADD-IP: Special case for ABORT chunks 2391 * F4) One special consideration is that ABORT Chunks arriving 2392 * destined to the IP address being deleted MUST be 2393 * ignored (see Section 5.3.1 for further details). 2394 */ 2395 if (SCTP_ADDR_DEL == 2396 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2397 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 2398 2399 return __sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2400 } 2401 2402 static sctp_disposition_t __sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2403 const struct sctp_association *asoc, 2404 const sctp_subtype_t type, 2405 void *arg, 2406 sctp_cmd_seq_t *commands) 2407 { 2408 struct sctp_chunk *chunk = arg; 2409 unsigned len; 2410 __be16 error = SCTP_ERROR_NO_ERROR; 2411 2412 /* See if we have an error cause code in the chunk. */ 2413 len = ntohs(chunk->chunk_hdr->length); 2414 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2415 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2416 2417 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2418 /* ASSOC_FAILED will DELETE_TCB. */ 2419 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2420 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2421 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2422 2423 return SCTP_DISPOSITION_ABORT; 2424 } 2425 2426 /* 2427 * Process an ABORT. (COOKIE-WAIT state) 2428 * 2429 * See sctp_sf_do_9_1_abort() above. 2430 */ 2431 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2432 const struct sctp_association *asoc, 2433 const sctp_subtype_t type, 2434 void *arg, 2435 sctp_cmd_seq_t *commands) 2436 { 2437 struct sctp_chunk *chunk = arg; 2438 unsigned len; 2439 __be16 error = SCTP_ERROR_NO_ERROR; 2440 2441 if (!sctp_vtag_verify_either(chunk, asoc)) 2442 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2443 2444 /* Make sure that the ABORT chunk has a valid length. 2445 * Since this is an ABORT chunk, we have to discard it 2446 * because of the following text: 2447 * RFC 2960, Section 3.3.7 2448 * If an endpoint receives an ABORT with a format error or for an 2449 * association that doesn't exist, it MUST silently discard it. 2450 * Becasue the length is "invalid", we can't really discard just 2451 * as we do not know its true length. So, to be safe, discard the 2452 * packet. 2453 */ 2454 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2455 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2456 2457 /* See if we have an error cause code in the chunk. */ 2458 len = ntohs(chunk->chunk_hdr->length); 2459 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2460 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2461 2462 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, 2463 chunk->transport); 2464 } 2465 2466 /* 2467 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2468 */ 2469 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2470 const struct sctp_association *asoc, 2471 const sctp_subtype_t type, 2472 void *arg, 2473 sctp_cmd_seq_t *commands) 2474 { 2475 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, 2476 ENOPROTOOPT, asoc, 2477 (struct sctp_transport *)arg); 2478 } 2479 2480 /* 2481 * Process an ABORT. (COOKIE-ECHOED state) 2482 */ 2483 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2484 const struct sctp_association *asoc, 2485 const sctp_subtype_t type, 2486 void *arg, 2487 sctp_cmd_seq_t *commands) 2488 { 2489 /* There is a single T1 timer, so we should be able to use 2490 * common function with the COOKIE-WAIT state. 2491 */ 2492 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2493 } 2494 2495 /* 2496 * Stop T1 timer and abort association with "INIT failed". 2497 * 2498 * This is common code called by several sctp_sf_*_abort() functions above. 2499 */ 2500 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2501 __be16 error, int sk_err, 2502 const struct sctp_association *asoc, 2503 struct sctp_transport *transport) 2504 { 2505 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2506 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2507 SCTP_STATE(SCTP_STATE_CLOSED)); 2508 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2509 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2510 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2511 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2512 /* CMD_INIT_FAILED will DELETE_TCB. */ 2513 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2514 SCTP_PERR(error)); 2515 return SCTP_DISPOSITION_ABORT; 2516 } 2517 2518 /* 2519 * sctp_sf_do_9_2_shut 2520 * 2521 * Section: 9.2 2522 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2523 * - enter the SHUTDOWN-RECEIVED state, 2524 * 2525 * - stop accepting new data from its SCTP user 2526 * 2527 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2528 * that all its outstanding DATA chunks have been received by the 2529 * SHUTDOWN sender. 2530 * 2531 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2532 * send a SHUTDOWN in response to a ULP request. And should discard 2533 * subsequent SHUTDOWN chunks. 2534 * 2535 * If there are still outstanding DATA chunks left, the SHUTDOWN 2536 * receiver shall continue to follow normal data transmission 2537 * procedures defined in Section 6 until all outstanding DATA chunks 2538 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2539 * new data from its SCTP user. 2540 * 2541 * Verification Tag: 8.5 Verification Tag [Normal verification] 2542 * 2543 * Inputs 2544 * (endpoint, asoc, chunk) 2545 * 2546 * Outputs 2547 * (asoc, reply_msg, msg_up, timers, counters) 2548 * 2549 * The return value is the disposition of the chunk. 2550 */ 2551 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2552 const struct sctp_association *asoc, 2553 const sctp_subtype_t type, 2554 void *arg, 2555 sctp_cmd_seq_t *commands) 2556 { 2557 struct sctp_chunk *chunk = arg; 2558 sctp_shutdownhdr_t *sdh; 2559 sctp_disposition_t disposition; 2560 struct sctp_ulpevent *ev; 2561 __u32 ctsn; 2562 2563 if (!sctp_vtag_verify(chunk, asoc)) 2564 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2565 2566 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2567 if (!sctp_chunk_length_valid(chunk, 2568 sizeof(struct sctp_shutdown_chunk_t))) 2569 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2570 commands); 2571 2572 /* Convert the elaborate header. */ 2573 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2574 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2575 chunk->subh.shutdown_hdr = sdh; 2576 ctsn = ntohl(sdh->cum_tsn_ack); 2577 2578 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2579 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2580 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2581 return SCTP_DISPOSITION_DISCARD; 2582 } 2583 2584 /* If Cumulative TSN Ack beyond the max tsn currently 2585 * send, terminating the association and respond to the 2586 * sender with an ABORT. 2587 */ 2588 if (!TSN_lt(ctsn, asoc->next_tsn)) 2589 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 2590 2591 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2592 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2593 * inform the application that it should cease sending data. 2594 */ 2595 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2596 if (!ev) { 2597 disposition = SCTP_DISPOSITION_NOMEM; 2598 goto out; 2599 } 2600 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2601 2602 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2603 * - enter the SHUTDOWN-RECEIVED state, 2604 * - stop accepting new data from its SCTP user 2605 * 2606 * [This is implicit in the new state.] 2607 */ 2608 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2609 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2610 disposition = SCTP_DISPOSITION_CONSUME; 2611 2612 if (sctp_outq_is_empty(&asoc->outqueue)) { 2613 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2614 arg, commands); 2615 } 2616 2617 if (SCTP_DISPOSITION_NOMEM == disposition) 2618 goto out; 2619 2620 /* - verify, by checking the Cumulative TSN Ack field of the 2621 * chunk, that all its outstanding DATA chunks have been 2622 * received by the SHUTDOWN sender. 2623 */ 2624 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2625 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2626 2627 out: 2628 return disposition; 2629 } 2630 2631 /* 2632 * sctp_sf_do_9_2_shut_ctsn 2633 * 2634 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2635 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2636 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2637 * MUST be processed. 2638 */ 2639 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(const struct sctp_endpoint *ep, 2640 const struct sctp_association *asoc, 2641 const sctp_subtype_t type, 2642 void *arg, 2643 sctp_cmd_seq_t *commands) 2644 { 2645 struct sctp_chunk *chunk = arg; 2646 sctp_shutdownhdr_t *sdh; 2647 __u32 ctsn; 2648 2649 if (!sctp_vtag_verify(chunk, asoc)) 2650 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2651 2652 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2653 if (!sctp_chunk_length_valid(chunk, 2654 sizeof(struct sctp_shutdown_chunk_t))) 2655 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2656 commands); 2657 2658 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2659 ctsn = ntohl(sdh->cum_tsn_ack); 2660 2661 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2662 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2663 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2664 return SCTP_DISPOSITION_DISCARD; 2665 } 2666 2667 /* If Cumulative TSN Ack beyond the max tsn currently 2668 * send, terminating the association and respond to the 2669 * sender with an ABORT. 2670 */ 2671 if (!TSN_lt(ctsn, asoc->next_tsn)) 2672 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 2673 2674 /* verify, by checking the Cumulative TSN Ack field of the 2675 * chunk, that all its outstanding DATA chunks have been 2676 * received by the SHUTDOWN sender. 2677 */ 2678 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2679 SCTP_BE32(sdh->cum_tsn_ack)); 2680 2681 return SCTP_DISPOSITION_CONSUME; 2682 } 2683 2684 /* RFC 2960 9.2 2685 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2686 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2687 * transport addresses (either in the IP addresses or in the INIT chunk) 2688 * that belong to this association, it should discard the INIT chunk and 2689 * retransmit the SHUTDOWN ACK chunk. 2690 */ 2691 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2692 const struct sctp_association *asoc, 2693 const sctp_subtype_t type, 2694 void *arg, 2695 sctp_cmd_seq_t *commands) 2696 { 2697 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2698 struct sctp_chunk *reply; 2699 2700 /* Make sure that the chunk has a valid length */ 2701 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2702 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2703 commands); 2704 2705 /* Since we are not going to really process this INIT, there 2706 * is no point in verifying chunk boundries. Just generate 2707 * the SHUTDOWN ACK. 2708 */ 2709 reply = sctp_make_shutdown_ack(asoc, chunk); 2710 if (NULL == reply) 2711 goto nomem; 2712 2713 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2714 * the T2-SHUTDOWN timer. 2715 */ 2716 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2717 2718 /* and restart the T2-shutdown timer. */ 2719 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2720 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2721 2722 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2723 2724 return SCTP_DISPOSITION_CONSUME; 2725 nomem: 2726 return SCTP_DISPOSITION_NOMEM; 2727 } 2728 2729 /* 2730 * sctp_sf_do_ecn_cwr 2731 * 2732 * Section: Appendix A: Explicit Congestion Notification 2733 * 2734 * CWR: 2735 * 2736 * RFC 2481 details a specific bit for a sender to send in the header of 2737 * its next outbound TCP segment to indicate to its peer that it has 2738 * reduced its congestion window. This is termed the CWR bit. For 2739 * SCTP the same indication is made by including the CWR chunk. 2740 * This chunk contains one data element, i.e. the TSN number that 2741 * was sent in the ECNE chunk. This element represents the lowest 2742 * TSN number in the datagram that was originally marked with the 2743 * CE bit. 2744 * 2745 * Verification Tag: 8.5 Verification Tag [Normal verification] 2746 * Inputs 2747 * (endpoint, asoc, chunk) 2748 * 2749 * Outputs 2750 * (asoc, reply_msg, msg_up, timers, counters) 2751 * 2752 * The return value is the disposition of the chunk. 2753 */ 2754 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2755 const struct sctp_association *asoc, 2756 const sctp_subtype_t type, 2757 void *arg, 2758 sctp_cmd_seq_t *commands) 2759 { 2760 sctp_cwrhdr_t *cwr; 2761 struct sctp_chunk *chunk = arg; 2762 u32 lowest_tsn; 2763 2764 if (!sctp_vtag_verify(chunk, asoc)) 2765 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2766 2767 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2768 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2769 commands); 2770 2771 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2772 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2773 2774 lowest_tsn = ntohl(cwr->lowest_tsn); 2775 2776 /* Does this CWR ack the last sent congestion notification? */ 2777 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2778 /* Stop sending ECNE. */ 2779 sctp_add_cmd_sf(commands, 2780 SCTP_CMD_ECN_CWR, 2781 SCTP_U32(lowest_tsn)); 2782 } 2783 return SCTP_DISPOSITION_CONSUME; 2784 } 2785 2786 /* 2787 * sctp_sf_do_ecne 2788 * 2789 * Section: Appendix A: Explicit Congestion Notification 2790 * 2791 * ECN-Echo 2792 * 2793 * RFC 2481 details a specific bit for a receiver to send back in its 2794 * TCP acknowledgements to notify the sender of the Congestion 2795 * Experienced (CE) bit having arrived from the network. For SCTP this 2796 * same indication is made by including the ECNE chunk. This chunk 2797 * contains one data element, i.e. the lowest TSN associated with the IP 2798 * datagram marked with the CE bit..... 2799 * 2800 * Verification Tag: 8.5 Verification Tag [Normal verification] 2801 * Inputs 2802 * (endpoint, asoc, chunk) 2803 * 2804 * Outputs 2805 * (asoc, reply_msg, msg_up, timers, counters) 2806 * 2807 * The return value is the disposition of the chunk. 2808 */ 2809 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2810 const struct sctp_association *asoc, 2811 const sctp_subtype_t type, 2812 void *arg, 2813 sctp_cmd_seq_t *commands) 2814 { 2815 sctp_ecnehdr_t *ecne; 2816 struct sctp_chunk *chunk = arg; 2817 2818 if (!sctp_vtag_verify(chunk, asoc)) 2819 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2820 2821 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2822 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2823 commands); 2824 2825 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2826 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2827 2828 /* If this is a newer ECNE than the last CWR packet we sent out */ 2829 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2830 SCTP_U32(ntohl(ecne->lowest_tsn))); 2831 2832 return SCTP_DISPOSITION_CONSUME; 2833 } 2834 2835 /* 2836 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2837 * 2838 * The SCTP endpoint MUST always acknowledge the reception of each valid 2839 * DATA chunk. 2840 * 2841 * The guidelines on delayed acknowledgement algorithm specified in 2842 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2843 * acknowledgement SHOULD be generated for at least every second packet 2844 * (not every second DATA chunk) received, and SHOULD be generated within 2845 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2846 * situations it may be beneficial for an SCTP transmitter to be more 2847 * conservative than the algorithms detailed in this document allow. 2848 * However, an SCTP transmitter MUST NOT be more aggressive than the 2849 * following algorithms allow. 2850 * 2851 * A SCTP receiver MUST NOT generate more than one SACK for every 2852 * incoming packet, other than to update the offered window as the 2853 * receiving application consumes new data. 2854 * 2855 * Verification Tag: 8.5 Verification Tag [Normal verification] 2856 * 2857 * Inputs 2858 * (endpoint, asoc, chunk) 2859 * 2860 * Outputs 2861 * (asoc, reply_msg, msg_up, timers, counters) 2862 * 2863 * The return value is the disposition of the chunk. 2864 */ 2865 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2866 const struct sctp_association *asoc, 2867 const sctp_subtype_t type, 2868 void *arg, 2869 sctp_cmd_seq_t *commands) 2870 { 2871 struct sctp_chunk *chunk = arg; 2872 sctp_arg_t force = SCTP_NOFORCE(); 2873 int error; 2874 2875 if (!sctp_vtag_verify(chunk, asoc)) { 2876 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2877 SCTP_NULL()); 2878 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2879 } 2880 2881 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2882 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2883 commands); 2884 2885 error = sctp_eat_data(asoc, chunk, commands ); 2886 switch (error) { 2887 case SCTP_IERROR_NO_ERROR: 2888 break; 2889 case SCTP_IERROR_HIGH_TSN: 2890 case SCTP_IERROR_BAD_STREAM: 2891 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2892 goto discard_noforce; 2893 case SCTP_IERROR_DUP_TSN: 2894 case SCTP_IERROR_IGNORE_TSN: 2895 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2896 goto discard_force; 2897 case SCTP_IERROR_NO_DATA: 2898 goto consume; 2899 case SCTP_IERROR_PROTO_VIOLATION: 2900 return sctp_sf_abort_violation(ep, asoc, chunk, commands, 2901 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2902 default: 2903 BUG(); 2904 } 2905 2906 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2907 force = SCTP_FORCE(); 2908 2909 if (asoc->autoclose) { 2910 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2911 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2912 } 2913 2914 /* If this is the last chunk in a packet, we need to count it 2915 * toward sack generation. Note that we need to SACK every 2916 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2917 * THEM. We elect to NOT generate SACK's if the chunk fails 2918 * the verification tag test. 2919 * 2920 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2921 * 2922 * The SCTP endpoint MUST always acknowledge the reception of 2923 * each valid DATA chunk. 2924 * 2925 * The guidelines on delayed acknowledgement algorithm 2926 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2927 * Specifically, an acknowledgement SHOULD be generated for at 2928 * least every second packet (not every second DATA chunk) 2929 * received, and SHOULD be generated within 200 ms of the 2930 * arrival of any unacknowledged DATA chunk. In some 2931 * situations it may be beneficial for an SCTP transmitter to 2932 * be more conservative than the algorithms detailed in this 2933 * document allow. However, an SCTP transmitter MUST NOT be 2934 * more aggressive than the following algorithms allow. 2935 */ 2936 if (chunk->end_of_packet) 2937 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 2938 2939 return SCTP_DISPOSITION_CONSUME; 2940 2941 discard_force: 2942 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2943 * 2944 * When a packet arrives with duplicate DATA chunk(s) and with 2945 * no new DATA chunk(s), the endpoint MUST immediately send a 2946 * SACK with no delay. If a packet arrives with duplicate 2947 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2948 * MAY immediately send a SACK. Normally receipt of duplicate 2949 * DATA chunks will occur when the original SACK chunk was lost 2950 * and the peer's RTO has expired. The duplicate TSN number(s) 2951 * SHOULD be reported in the SACK as duplicate. 2952 */ 2953 /* In our case, we split the MAY SACK advice up whether or not 2954 * the last chunk is a duplicate.' 2955 */ 2956 if (chunk->end_of_packet) 2957 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2958 return SCTP_DISPOSITION_DISCARD; 2959 2960 discard_noforce: 2961 if (chunk->end_of_packet) 2962 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 2963 2964 return SCTP_DISPOSITION_DISCARD; 2965 consume: 2966 return SCTP_DISPOSITION_CONSUME; 2967 2968 } 2969 2970 /* 2971 * sctp_sf_eat_data_fast_4_4 2972 * 2973 * Section: 4 (4) 2974 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2975 * DATA chunks without delay. 2976 * 2977 * Verification Tag: 8.5 Verification Tag [Normal verification] 2978 * Inputs 2979 * (endpoint, asoc, chunk) 2980 * 2981 * Outputs 2982 * (asoc, reply_msg, msg_up, timers, counters) 2983 * 2984 * The return value is the disposition of the chunk. 2985 */ 2986 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2987 const struct sctp_association *asoc, 2988 const sctp_subtype_t type, 2989 void *arg, 2990 sctp_cmd_seq_t *commands) 2991 { 2992 struct sctp_chunk *chunk = arg; 2993 int error; 2994 2995 if (!sctp_vtag_verify(chunk, asoc)) { 2996 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2997 SCTP_NULL()); 2998 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2999 } 3000 3001 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3002 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3003 commands); 3004 3005 error = sctp_eat_data(asoc, chunk, commands ); 3006 switch (error) { 3007 case SCTP_IERROR_NO_ERROR: 3008 case SCTP_IERROR_HIGH_TSN: 3009 case SCTP_IERROR_DUP_TSN: 3010 case SCTP_IERROR_IGNORE_TSN: 3011 case SCTP_IERROR_BAD_STREAM: 3012 break; 3013 case SCTP_IERROR_NO_DATA: 3014 goto consume; 3015 case SCTP_IERROR_PROTO_VIOLATION: 3016 return sctp_sf_abort_violation(ep, asoc, chunk, commands, 3017 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3018 default: 3019 BUG(); 3020 } 3021 3022 /* Go a head and force a SACK, since we are shutting down. */ 3023 3024 /* Implementor's Guide. 3025 * 3026 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3027 * respond to each received packet containing one or more DATA chunk(s) 3028 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3029 */ 3030 if (chunk->end_of_packet) { 3031 /* We must delay the chunk creation since the cumulative 3032 * TSN has not been updated yet. 3033 */ 3034 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3035 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3036 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3037 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3038 } 3039 3040 consume: 3041 return SCTP_DISPOSITION_CONSUME; 3042 } 3043 3044 /* 3045 * Section: 6.2 Processing a Received SACK 3046 * D) Any time a SACK arrives, the endpoint performs the following: 3047 * 3048 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3049 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3050 * increasing, a SACK whose Cumulative TSN Ack is less than the 3051 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3052 * 3053 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3054 * of bytes still outstanding after processing the Cumulative TSN Ack 3055 * and the Gap Ack Blocks. 3056 * 3057 * iii) If the SACK is missing a TSN that was previously 3058 * acknowledged via a Gap Ack Block (e.g., the data receiver 3059 * reneged on the data), then mark the corresponding DATA chunk 3060 * as available for retransmit: Mark it as missing for fast 3061 * retransmit as described in Section 7.2.4 and if no retransmit 3062 * timer is running for the destination address to which the DATA 3063 * chunk was originally transmitted, then T3-rtx is started for 3064 * that destination address. 3065 * 3066 * Verification Tag: 8.5 Verification Tag [Normal verification] 3067 * 3068 * Inputs 3069 * (endpoint, asoc, chunk) 3070 * 3071 * Outputs 3072 * (asoc, reply_msg, msg_up, timers, counters) 3073 * 3074 * The return value is the disposition of the chunk. 3075 */ 3076 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 3077 const struct sctp_association *asoc, 3078 const sctp_subtype_t type, 3079 void *arg, 3080 sctp_cmd_seq_t *commands) 3081 { 3082 struct sctp_chunk *chunk = arg; 3083 sctp_sackhdr_t *sackh; 3084 __u32 ctsn; 3085 3086 if (!sctp_vtag_verify(chunk, asoc)) 3087 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3088 3089 /* Make sure that the SACK chunk has a valid length. */ 3090 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3091 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3092 commands); 3093 3094 /* Pull the SACK chunk from the data buffer */ 3095 sackh = sctp_sm_pull_sack(chunk); 3096 /* Was this a bogus SACK? */ 3097 if (!sackh) 3098 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3099 chunk->subh.sack_hdr = sackh; 3100 ctsn = ntohl(sackh->cum_tsn_ack); 3101 3102 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3103 * Ack Point, then drop the SACK. Since Cumulative TSN 3104 * Ack is monotonically increasing, a SACK whose 3105 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3106 * Point indicates an out-of-order SACK. 3107 */ 3108 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3109 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3110 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3111 return SCTP_DISPOSITION_DISCARD; 3112 } 3113 3114 /* If Cumulative TSN Ack beyond the max tsn currently 3115 * send, terminating the association and respond to the 3116 * sender with an ABORT. 3117 */ 3118 if (!TSN_lt(ctsn, asoc->next_tsn)) 3119 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 3120 3121 /* Return this SACK for further processing. */ 3122 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 3123 3124 /* Note: We do the rest of the work on the PROCESS_SACK 3125 * sideeffect. 3126 */ 3127 return SCTP_DISPOSITION_CONSUME; 3128 } 3129 3130 /* 3131 * Generate an ABORT in response to a packet. 3132 * 3133 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3134 * 3135 * 8) The receiver should respond to the sender of the OOTB packet with 3136 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3137 * MUST fill in the Verification Tag field of the outbound packet 3138 * with the value found in the Verification Tag field of the OOTB 3139 * packet and set the T-bit in the Chunk Flags to indicate that the 3140 * Verification Tag is reflected. After sending this ABORT, the 3141 * receiver of the OOTB packet shall discard the OOTB packet and take 3142 * no further action. 3143 * 3144 * Verification Tag: 3145 * 3146 * The return value is the disposition of the chunk. 3147 */ 3148 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 3149 const struct sctp_association *asoc, 3150 const sctp_subtype_t type, 3151 void *arg, 3152 sctp_cmd_seq_t *commands) 3153 { 3154 struct sctp_packet *packet = NULL; 3155 struct sctp_chunk *chunk = arg; 3156 struct sctp_chunk *abort; 3157 3158 packet = sctp_ootb_pkt_new(asoc, chunk); 3159 3160 if (packet) { 3161 /* Make an ABORT. The T bit will be set if the asoc 3162 * is NULL. 3163 */ 3164 abort = sctp_make_abort(asoc, chunk, 0); 3165 if (!abort) { 3166 sctp_ootb_pkt_free(packet); 3167 return SCTP_DISPOSITION_NOMEM; 3168 } 3169 3170 /* Reflect vtag if T-Bit is set */ 3171 if (sctp_test_T_bit(abort)) 3172 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3173 3174 /* Set the skb to the belonging sock for accounting. */ 3175 abort->skb->sk = ep->base.sk; 3176 3177 sctp_packet_append_chunk(packet, abort); 3178 3179 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3180 SCTP_PACKET(packet)); 3181 3182 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3183 3184 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3185 return SCTP_DISPOSITION_CONSUME; 3186 } 3187 3188 return SCTP_DISPOSITION_NOMEM; 3189 } 3190 3191 /* 3192 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3193 * event as ULP notification for each cause included in the chunk. 3194 * 3195 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3196 * 3197 * The return value is the disposition of the chunk. 3198 */ 3199 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 3200 const struct sctp_association *asoc, 3201 const sctp_subtype_t type, 3202 void *arg, 3203 sctp_cmd_seq_t *commands) 3204 { 3205 struct sctp_chunk *chunk = arg; 3206 3207 if (!sctp_vtag_verify(chunk, asoc)) 3208 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3209 3210 /* Make sure that the ERROR chunk has a valid length. */ 3211 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3212 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3213 commands); 3214 3215 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3216 SCTP_CHUNK(chunk)); 3217 3218 return SCTP_DISPOSITION_CONSUME; 3219 } 3220 3221 /* 3222 * Process an inbound SHUTDOWN ACK. 3223 * 3224 * From Section 9.2: 3225 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3226 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3227 * peer, and remove all record of the association. 3228 * 3229 * The return value is the disposition. 3230 */ 3231 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3232 const struct sctp_association *asoc, 3233 const sctp_subtype_t type, 3234 void *arg, 3235 sctp_cmd_seq_t *commands) 3236 { 3237 struct sctp_chunk *chunk = arg; 3238 struct sctp_chunk *reply; 3239 struct sctp_ulpevent *ev; 3240 3241 if (!sctp_vtag_verify(chunk, asoc)) 3242 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3243 3244 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3245 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3246 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3247 commands); 3248 /* 10.2 H) SHUTDOWN COMPLETE notification 3249 * 3250 * When SCTP completes the shutdown procedures (section 9.2) this 3251 * notification is passed to the upper layer. 3252 */ 3253 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3254 0, 0, 0, NULL, GFP_ATOMIC); 3255 if (!ev) 3256 goto nomem; 3257 3258 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3259 reply = sctp_make_shutdown_complete(asoc, chunk); 3260 if (!reply) 3261 goto nomem_chunk; 3262 3263 /* Do all the commands now (after allocation), so that we 3264 * have consistent state if memory allocation failes 3265 */ 3266 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3267 3268 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3269 * stop the T2-shutdown timer, 3270 */ 3271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3272 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3273 3274 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3275 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3276 3277 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3278 SCTP_STATE(SCTP_STATE_CLOSED)); 3279 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3280 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3281 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3282 3283 /* ...and remove all record of the association. */ 3284 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3285 return SCTP_DISPOSITION_DELETE_TCB; 3286 3287 nomem_chunk: 3288 sctp_ulpevent_free(ev); 3289 nomem: 3290 return SCTP_DISPOSITION_NOMEM; 3291 } 3292 3293 /* 3294 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3295 * 3296 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3297 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3298 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3299 * packet must fill in the Verification Tag field of the outbound 3300 * packet with the Verification Tag received in the SHUTDOWN ACK and 3301 * set the T-bit in the Chunk Flags to indicate that the Verification 3302 * Tag is reflected. 3303 * 3304 * 8) The receiver should respond to the sender of the OOTB packet with 3305 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3306 * MUST fill in the Verification Tag field of the outbound packet 3307 * with the value found in the Verification Tag field of the OOTB 3308 * packet and set the T-bit in the Chunk Flags to indicate that the 3309 * Verification Tag is reflected. After sending this ABORT, the 3310 * receiver of the OOTB packet shall discard the OOTB packet and take 3311 * no further action. 3312 */ 3313 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3314 const struct sctp_association *asoc, 3315 const sctp_subtype_t type, 3316 void *arg, 3317 sctp_cmd_seq_t *commands) 3318 { 3319 struct sctp_chunk *chunk = arg; 3320 struct sk_buff *skb = chunk->skb; 3321 sctp_chunkhdr_t *ch; 3322 __u8 *ch_end; 3323 int ootb_shut_ack = 0; 3324 3325 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3326 3327 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3328 do { 3329 /* Report violation if the chunk is less then minimal */ 3330 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3331 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3332 commands); 3333 3334 /* Now that we know we at least have a chunk header, 3335 * do things that are type appropriate. 3336 */ 3337 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3338 ootb_shut_ack = 1; 3339 3340 /* RFC 2960, Section 3.3.7 3341 * Moreover, under any circumstances, an endpoint that 3342 * receives an ABORT MUST NOT respond to that ABORT by 3343 * sending an ABORT of its own. 3344 */ 3345 if (SCTP_CID_ABORT == ch->type) 3346 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3347 3348 /* Report violation if chunk len overflows */ 3349 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3350 if (ch_end > skb_tail_pointer(skb)) 3351 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3352 commands); 3353 3354 ch = (sctp_chunkhdr_t *) ch_end; 3355 } while (ch_end < skb_tail_pointer(skb)); 3356 3357 if (ootb_shut_ack) 3358 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3359 else 3360 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3361 } 3362 3363 /* 3364 * Handle an "Out of the blue" SHUTDOWN ACK. 3365 * 3366 * Section: 8.4 5, sctpimpguide 2.41. 3367 * 3368 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3369 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3370 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3371 * packet must fill in the Verification Tag field of the outbound 3372 * packet with the Verification Tag received in the SHUTDOWN ACK and 3373 * set the T-bit in the Chunk Flags to indicate that the Verification 3374 * Tag is reflected. 3375 * 3376 * Inputs 3377 * (endpoint, asoc, type, arg, commands) 3378 * 3379 * Outputs 3380 * (sctp_disposition_t) 3381 * 3382 * The return value is the disposition of the chunk. 3383 */ 3384 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3385 const struct sctp_association *asoc, 3386 const sctp_subtype_t type, 3387 void *arg, 3388 sctp_cmd_seq_t *commands) 3389 { 3390 struct sctp_packet *packet = NULL; 3391 struct sctp_chunk *chunk = arg; 3392 struct sctp_chunk *shut; 3393 3394 packet = sctp_ootb_pkt_new(asoc, chunk); 3395 3396 if (packet) { 3397 /* Make an SHUTDOWN_COMPLETE. 3398 * The T bit will be set if the asoc is NULL. 3399 */ 3400 shut = sctp_make_shutdown_complete(asoc, chunk); 3401 if (!shut) { 3402 sctp_ootb_pkt_free(packet); 3403 return SCTP_DISPOSITION_NOMEM; 3404 } 3405 3406 /* Reflect vtag if T-Bit is set */ 3407 if (sctp_test_T_bit(shut)) 3408 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3409 3410 /* Set the skb to the belonging sock for accounting. */ 3411 shut->skb->sk = ep->base.sk; 3412 3413 sctp_packet_append_chunk(packet, shut); 3414 3415 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3416 SCTP_PACKET(packet)); 3417 3418 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3419 3420 /* If the chunk length is invalid, we don't want to process 3421 * the reset of the packet. 3422 */ 3423 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3424 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3425 3426 /* We need to discard the rest of the packet to prevent 3427 * potential bomming attacks from additional bundled chunks. 3428 * This is documented in SCTP Threats ID. 3429 */ 3430 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3431 } 3432 3433 return SCTP_DISPOSITION_NOMEM; 3434 } 3435 3436 /* 3437 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3438 * 3439 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3440 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3441 * procedures in section 8.4 SHOULD be followed, in other words it 3442 * should be treated as an Out Of The Blue packet. 3443 * [This means that we do NOT check the Verification Tag on these 3444 * chunks. --piggy ] 3445 * 3446 */ 3447 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3448 const struct sctp_association *asoc, 3449 const sctp_subtype_t type, 3450 void *arg, 3451 sctp_cmd_seq_t *commands) 3452 { 3453 struct sctp_chunk *chunk = arg; 3454 3455 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3456 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3457 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3458 commands); 3459 3460 /* Although we do have an association in this case, it corresponds 3461 * to a restarted association. So the packet is treated as an OOTB 3462 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3463 * called with a NULL association. 3464 */ 3465 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3466 3467 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3468 } 3469 3470 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3471 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3472 const struct sctp_association *asoc, 3473 const sctp_subtype_t type, void *arg, 3474 sctp_cmd_seq_t *commands) 3475 { 3476 struct sctp_chunk *chunk = arg; 3477 struct sctp_chunk *asconf_ack = NULL; 3478 struct sctp_paramhdr *err_param = NULL; 3479 sctp_addiphdr_t *hdr; 3480 union sctp_addr_param *addr_param; 3481 __u32 serial; 3482 int length; 3483 3484 if (!sctp_vtag_verify(chunk, asoc)) { 3485 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3486 SCTP_NULL()); 3487 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3488 } 3489 3490 /* ADD-IP: Section 4.1.1 3491 * This chunk MUST be sent in an authenticated way by using 3492 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3493 * is received unauthenticated it MUST be silently discarded as 3494 * described in [I-D.ietf-tsvwg-sctp-auth]. 3495 */ 3496 if (!sctp_addip_noauth && !chunk->auth) 3497 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3498 3499 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3500 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3501 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3502 commands); 3503 3504 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3505 serial = ntohl(hdr->serial); 3506 3507 addr_param = (union sctp_addr_param *)hdr->params; 3508 length = ntohs(addr_param->p.length); 3509 if (length < sizeof(sctp_paramhdr_t)) 3510 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3511 (void *)addr_param, commands); 3512 3513 /* Verify the ASCONF chunk before processing it. */ 3514 if (!sctp_verify_asconf(asoc, 3515 (sctp_paramhdr_t *)((void *)addr_param + length), 3516 (void *)chunk->chunk_end, 3517 &err_param)) 3518 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3519 (void *)err_param, commands); 3520 3521 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3522 * the endpoint stored in a new association variable 3523 * 'Peer-Serial-Number'. 3524 */ 3525 if (serial == asoc->peer.addip_serial + 1) { 3526 /* If this is the first instance of ASCONF in the packet, 3527 * we can clean our old ASCONF-ACKs. 3528 */ 3529 if (!chunk->has_asconf) 3530 sctp_assoc_clean_asconf_ack_cache(asoc); 3531 3532 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3533 * expected, process the ASCONF as described below and after 3534 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3535 * the response packet and cache a copy of it (in the event it 3536 * later needs to be retransmitted). 3537 * 3538 * Essentially, do V1-V5. 3539 */ 3540 asconf_ack = sctp_process_asconf((struct sctp_association *) 3541 asoc, chunk); 3542 if (!asconf_ack) 3543 return SCTP_DISPOSITION_NOMEM; 3544 } else if (serial < asoc->peer.addip_serial + 1) { 3545 /* ADDIP 5.2 E2) 3546 * If the value found in the Sequence Number is less than the 3547 * ('Peer- Sequence-Number' + 1), simply skip to the next 3548 * ASCONF, and include in the outbound response packet 3549 * any previously cached ASCONF-ACK response that was 3550 * sent and saved that matches the Sequence Number of the 3551 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3552 * Chunk exists. This will occur when an older ASCONF 3553 * arrives out of order. In such a case, the receiver 3554 * should skip the ASCONF Chunk and not include ASCONF-ACK 3555 * Chunk for that chunk. 3556 */ 3557 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3558 if (!asconf_ack) 3559 return SCTP_DISPOSITION_DISCARD; 3560 3561 /* Reset the transport so that we select the correct one 3562 * this time around. This is to make sure that we don't 3563 * accidentally use a stale transport that's been removed. 3564 */ 3565 asconf_ack->transport = NULL; 3566 } else { 3567 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3568 * it must be either a stale packet or from an attacker. 3569 */ 3570 return SCTP_DISPOSITION_DISCARD; 3571 } 3572 3573 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3574 * containing the ASCONF-ACK Chunks MUST be the source address of 3575 * the SCTP packet that held the ASCONF Chunks. 3576 * 3577 * To do this properly, we'll set the destination address of the chunk 3578 * and at the transmit time, will try look up the transport to use. 3579 * Since ASCONFs may be bundled, the correct transport may not be 3580 * created until we process the entire packet, thus this workaround. 3581 */ 3582 asconf_ack->dest = chunk->source; 3583 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3584 3585 return SCTP_DISPOSITION_CONSUME; 3586 } 3587 3588 /* 3589 * ADDIP Section 4.3 General rules for address manipulation 3590 * When building TLV parameters for the ASCONF Chunk that will add or 3591 * delete IP addresses the D0 to D13 rules should be applied: 3592 */ 3593 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3594 const struct sctp_association *asoc, 3595 const sctp_subtype_t type, void *arg, 3596 sctp_cmd_seq_t *commands) 3597 { 3598 struct sctp_chunk *asconf_ack = arg; 3599 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3600 struct sctp_chunk *abort; 3601 struct sctp_paramhdr *err_param = NULL; 3602 sctp_addiphdr_t *addip_hdr; 3603 __u32 sent_serial, rcvd_serial; 3604 3605 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3606 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3607 SCTP_NULL()); 3608 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3609 } 3610 3611 /* ADD-IP, Section 4.1.2: 3612 * This chunk MUST be sent in an authenticated way by using 3613 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3614 * is received unauthenticated it MUST be silently discarded as 3615 * described in [I-D.ietf-tsvwg-sctp-auth]. 3616 */ 3617 if (!sctp_addip_noauth && !asconf_ack->auth) 3618 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 3619 3620 /* Make sure that the ADDIP chunk has a valid length. */ 3621 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3622 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3623 commands); 3624 3625 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3626 rcvd_serial = ntohl(addip_hdr->serial); 3627 3628 /* Verify the ASCONF-ACK chunk before processing it. */ 3629 if (!sctp_verify_asconf(asoc, 3630 (sctp_paramhdr_t *)addip_hdr->params, 3631 (void *)asconf_ack->chunk_end, 3632 &err_param)) 3633 return sctp_sf_violation_paramlen(ep, asoc, type, arg, 3634 (void *)err_param, commands); 3635 3636 if (last_asconf) { 3637 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3638 sent_serial = ntohl(addip_hdr->serial); 3639 } else { 3640 sent_serial = asoc->addip_serial - 1; 3641 } 3642 3643 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3644 * equal to the next serial number to be used but no ASCONF chunk is 3645 * outstanding the endpoint MUST ABORT the association. Note that a 3646 * sequence number is greater than if it is no more than 2^^31-1 3647 * larger than the current sequence number (using serial arithmetic). 3648 */ 3649 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3650 !(asoc->addip_last_asconf)) { 3651 abort = sctp_make_abort(asoc, asconf_ack, 3652 sizeof(sctp_errhdr_t)); 3653 if (abort) { 3654 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3655 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3656 SCTP_CHUNK(abort)); 3657 } 3658 /* We are going to ABORT, so we might as well stop 3659 * processing the rest of the chunks in the packet. 3660 */ 3661 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3662 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3663 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3664 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3665 SCTP_ERROR(ECONNABORTED)); 3666 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3667 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3668 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3669 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3670 return SCTP_DISPOSITION_ABORT; 3671 } 3672 3673 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3674 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3675 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3676 3677 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3678 asconf_ack)) 3679 return SCTP_DISPOSITION_CONSUME; 3680 3681 abort = sctp_make_abort(asoc, asconf_ack, 3682 sizeof(sctp_errhdr_t)); 3683 if (abort) { 3684 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3685 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3686 SCTP_CHUNK(abort)); 3687 } 3688 /* We are going to ABORT, so we might as well stop 3689 * processing the rest of the chunks in the packet. 3690 */ 3691 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3692 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3693 SCTP_ERROR(ECONNABORTED)); 3694 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3695 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3696 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3697 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3698 return SCTP_DISPOSITION_ABORT; 3699 } 3700 3701 return SCTP_DISPOSITION_DISCARD; 3702 } 3703 3704 /* 3705 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3706 * 3707 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3708 * its cumulative TSN point to the value carried in the FORWARD TSN 3709 * chunk, and then MUST further advance its cumulative TSN point locally 3710 * if possible. 3711 * After the above processing, the data receiver MUST stop reporting any 3712 * missing TSNs earlier than or equal to the new cumulative TSN point. 3713 * 3714 * Verification Tag: 8.5 Verification Tag [Normal verification] 3715 * 3716 * The return value is the disposition of the chunk. 3717 */ 3718 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3719 const struct sctp_association *asoc, 3720 const sctp_subtype_t type, 3721 void *arg, 3722 sctp_cmd_seq_t *commands) 3723 { 3724 struct sctp_chunk *chunk = arg; 3725 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3726 struct sctp_fwdtsn_skip *skip; 3727 __u16 len; 3728 __u32 tsn; 3729 3730 if (!sctp_vtag_verify(chunk, asoc)) { 3731 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3732 SCTP_NULL()); 3733 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3734 } 3735 3736 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3737 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3738 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3739 commands); 3740 3741 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3742 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3743 len = ntohs(chunk->chunk_hdr->length); 3744 len -= sizeof(struct sctp_chunkhdr); 3745 skb_pull(chunk->skb, len); 3746 3747 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3748 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3749 3750 /* The TSN is too high--silently discard the chunk and count on it 3751 * getting retransmitted later. 3752 */ 3753 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3754 goto discard_noforce; 3755 3756 /* Silently discard the chunk if stream-id is not valid */ 3757 sctp_walk_fwdtsn(skip, chunk) { 3758 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3759 goto discard_noforce; 3760 } 3761 3762 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3763 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3764 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3765 SCTP_CHUNK(chunk)); 3766 3767 /* Count this as receiving DATA. */ 3768 if (asoc->autoclose) { 3769 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3770 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3771 } 3772 3773 /* FIXME: For now send a SACK, but DATA processing may 3774 * send another. 3775 */ 3776 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3777 3778 return SCTP_DISPOSITION_CONSUME; 3779 3780 discard_noforce: 3781 return SCTP_DISPOSITION_DISCARD; 3782 } 3783 3784 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3785 const struct sctp_endpoint *ep, 3786 const struct sctp_association *asoc, 3787 const sctp_subtype_t type, 3788 void *arg, 3789 sctp_cmd_seq_t *commands) 3790 { 3791 struct sctp_chunk *chunk = arg; 3792 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3793 struct sctp_fwdtsn_skip *skip; 3794 __u16 len; 3795 __u32 tsn; 3796 3797 if (!sctp_vtag_verify(chunk, asoc)) { 3798 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3799 SCTP_NULL()); 3800 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3801 } 3802 3803 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3804 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3805 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3806 commands); 3807 3808 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3809 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3810 len = ntohs(chunk->chunk_hdr->length); 3811 len -= sizeof(struct sctp_chunkhdr); 3812 skb_pull(chunk->skb, len); 3813 3814 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3815 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3816 3817 /* The TSN is too high--silently discard the chunk and count on it 3818 * getting retransmitted later. 3819 */ 3820 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3821 goto gen_shutdown; 3822 3823 /* Silently discard the chunk if stream-id is not valid */ 3824 sctp_walk_fwdtsn(skip, chunk) { 3825 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3826 goto gen_shutdown; 3827 } 3828 3829 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3830 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3831 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3832 SCTP_CHUNK(chunk)); 3833 3834 /* Go a head and force a SACK, since we are shutting down. */ 3835 gen_shutdown: 3836 /* Implementor's Guide. 3837 * 3838 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3839 * respond to each received packet containing one or more DATA chunk(s) 3840 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3841 */ 3842 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3843 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3844 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3845 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3846 3847 return SCTP_DISPOSITION_CONSUME; 3848 } 3849 3850 /* 3851 * SCTP-AUTH Section 6.3 Receving authenticated chukns 3852 * 3853 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3854 * Identifier field. If this algorithm was not specified by the 3855 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3856 * during association setup, the AUTH chunk and all chunks after it MUST 3857 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3858 * defined in Section 4.1. 3859 * 3860 * If an endpoint with no shared key receives a Shared Key Identifier 3861 * other than 0, it MUST silently discard all authenticated chunks. If 3862 * the endpoint has at least one endpoint pair shared key for the peer, 3863 * it MUST use the key specified by the Shared Key Identifier if a 3864 * key has been configured for that Shared Key Identifier. If no 3865 * endpoint pair shared key has been configured for that Shared Key 3866 * Identifier, all authenticated chunks MUST be silently discarded. 3867 * 3868 * Verification Tag: 8.5 Verification Tag [Normal verification] 3869 * 3870 * The return value is the disposition of the chunk. 3871 */ 3872 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 3873 const struct sctp_association *asoc, 3874 const sctp_subtype_t type, 3875 struct sctp_chunk *chunk) 3876 { 3877 struct sctp_authhdr *auth_hdr; 3878 struct sctp_hmac *hmac; 3879 unsigned int sig_len; 3880 __u16 key_id; 3881 __u8 *save_digest; 3882 __u8 *digest; 3883 3884 /* Pull in the auth header, so we can do some more verification */ 3885 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3886 chunk->subh.auth_hdr = auth_hdr; 3887 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3888 3889 /* Make sure that we suport the HMAC algorithm from the auth 3890 * chunk. 3891 */ 3892 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 3893 return SCTP_IERROR_AUTH_BAD_HMAC; 3894 3895 /* Make sure that the provided shared key identifier has been 3896 * configured 3897 */ 3898 key_id = ntohs(auth_hdr->shkey_id); 3899 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 3900 return SCTP_IERROR_AUTH_BAD_KEYID; 3901 3902 3903 /* Make sure that the length of the signature matches what 3904 * we expect. 3905 */ 3906 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 3907 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 3908 if (sig_len != hmac->hmac_len) 3909 return SCTP_IERROR_PROTO_VIOLATION; 3910 3911 /* Now that we've done validation checks, we can compute and 3912 * verify the hmac. The steps involved are: 3913 * 1. Save the digest from the chunk. 3914 * 2. Zero out the digest in the chunk. 3915 * 3. Compute the new digest 3916 * 4. Compare saved and new digests. 3917 */ 3918 digest = auth_hdr->hmac; 3919 skb_pull(chunk->skb, sig_len); 3920 3921 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 3922 if (!save_digest) 3923 goto nomem; 3924 3925 memset(digest, 0, sig_len); 3926 3927 sctp_auth_calculate_hmac(asoc, chunk->skb, 3928 (struct sctp_auth_chunk *)chunk->chunk_hdr, 3929 GFP_ATOMIC); 3930 3931 /* Discard the packet if the digests do not match */ 3932 if (memcmp(save_digest, digest, sig_len)) { 3933 kfree(save_digest); 3934 return SCTP_IERROR_BAD_SIG; 3935 } 3936 3937 kfree(save_digest); 3938 chunk->auth = 1; 3939 3940 return SCTP_IERROR_NO_ERROR; 3941 nomem: 3942 return SCTP_IERROR_NOMEM; 3943 } 3944 3945 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep, 3946 const struct sctp_association *asoc, 3947 const sctp_subtype_t type, 3948 void *arg, 3949 sctp_cmd_seq_t *commands) 3950 { 3951 struct sctp_authhdr *auth_hdr; 3952 struct sctp_chunk *chunk = arg; 3953 struct sctp_chunk *err_chunk; 3954 sctp_ierror_t error; 3955 3956 /* Make sure that the peer has AUTH capable */ 3957 if (!asoc->peer.auth_capable) 3958 return sctp_sf_unk_chunk(ep, asoc, type, arg, commands); 3959 3960 if (!sctp_vtag_verify(chunk, asoc)) { 3961 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3962 SCTP_NULL()); 3963 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3964 } 3965 3966 /* Make sure that the AUTH chunk has valid length. */ 3967 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 3968 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3969 commands); 3970 3971 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3972 error = sctp_sf_authenticate(ep, asoc, type, chunk); 3973 switch (error) { 3974 case SCTP_IERROR_AUTH_BAD_HMAC: 3975 /* Generate the ERROR chunk and discard the rest 3976 * of the packet 3977 */ 3978 err_chunk = sctp_make_op_error(asoc, chunk, 3979 SCTP_ERROR_UNSUP_HMAC, 3980 &auth_hdr->hmac_id, 3981 sizeof(__u16), 0); 3982 if (err_chunk) { 3983 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3984 SCTP_CHUNK(err_chunk)); 3985 } 3986 /* Fall Through */ 3987 case SCTP_IERROR_AUTH_BAD_KEYID: 3988 case SCTP_IERROR_BAD_SIG: 3989 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3990 break; 3991 case SCTP_IERROR_PROTO_VIOLATION: 3992 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3993 commands); 3994 break; 3995 case SCTP_IERROR_NOMEM: 3996 return SCTP_DISPOSITION_NOMEM; 3997 default: 3998 break; 3999 } 4000 4001 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4002 struct sctp_ulpevent *ev; 4003 4004 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4005 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4006 4007 if (!ev) 4008 return -ENOMEM; 4009 4010 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4011 SCTP_ULPEVENT(ev)); 4012 } 4013 4014 return SCTP_DISPOSITION_CONSUME; 4015 } 4016 4017 /* 4018 * Process an unknown chunk. 4019 * 4020 * Section: 3.2. Also, 2.1 in the implementor's guide. 4021 * 4022 * Chunk Types are encoded such that the highest-order two bits specify 4023 * the action that must be taken if the processing endpoint does not 4024 * recognize the Chunk Type. 4025 * 4026 * 00 - Stop processing this SCTP packet and discard it, do not process 4027 * any further chunks within it. 4028 * 4029 * 01 - Stop processing this SCTP packet and discard it, do not process 4030 * any further chunks within it, and report the unrecognized 4031 * chunk in an 'Unrecognized Chunk Type'. 4032 * 4033 * 10 - Skip this chunk and continue processing. 4034 * 4035 * 11 - Skip this chunk and continue processing, but report in an ERROR 4036 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4037 * 4038 * The return value is the disposition of the chunk. 4039 */ 4040 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 4041 const struct sctp_association *asoc, 4042 const sctp_subtype_t type, 4043 void *arg, 4044 sctp_cmd_seq_t *commands) 4045 { 4046 struct sctp_chunk *unk_chunk = arg; 4047 struct sctp_chunk *err_chunk; 4048 sctp_chunkhdr_t *hdr; 4049 4050 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 4051 4052 if (!sctp_vtag_verify(unk_chunk, asoc)) 4053 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4054 4055 /* Make sure that the chunk has a valid length. 4056 * Since we don't know the chunk type, we use a general 4057 * chunkhdr structure to make a comparison. 4058 */ 4059 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4060 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4061 commands); 4062 4063 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4064 case SCTP_CID_ACTION_DISCARD: 4065 /* Discard the packet. */ 4066 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4067 break; 4068 case SCTP_CID_ACTION_DISCARD_ERR: 4069 /* Generate an ERROR chunk as response. */ 4070 hdr = unk_chunk->chunk_hdr; 4071 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4072 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4073 WORD_ROUND(ntohs(hdr->length)), 4074 0); 4075 if (err_chunk) { 4076 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4077 SCTP_CHUNK(err_chunk)); 4078 } 4079 4080 /* Discard the packet. */ 4081 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4082 return SCTP_DISPOSITION_CONSUME; 4083 break; 4084 case SCTP_CID_ACTION_SKIP: 4085 /* Skip the chunk. */ 4086 return SCTP_DISPOSITION_DISCARD; 4087 break; 4088 case SCTP_CID_ACTION_SKIP_ERR: 4089 /* Generate an ERROR chunk as response. */ 4090 hdr = unk_chunk->chunk_hdr; 4091 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4092 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4093 WORD_ROUND(ntohs(hdr->length)), 4094 0); 4095 if (err_chunk) { 4096 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4097 SCTP_CHUNK(err_chunk)); 4098 } 4099 /* Skip the chunk. */ 4100 return SCTP_DISPOSITION_CONSUME; 4101 break; 4102 default: 4103 break; 4104 } 4105 4106 return SCTP_DISPOSITION_DISCARD; 4107 } 4108 4109 /* 4110 * Discard the chunk. 4111 * 4112 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4113 * [Too numerous to mention...] 4114 * Verification Tag: No verification needed. 4115 * Inputs 4116 * (endpoint, asoc, chunk) 4117 * 4118 * Outputs 4119 * (asoc, reply_msg, msg_up, timers, counters) 4120 * 4121 * The return value is the disposition of the chunk. 4122 */ 4123 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 4124 const struct sctp_association *asoc, 4125 const sctp_subtype_t type, 4126 void *arg, 4127 sctp_cmd_seq_t *commands) 4128 { 4129 struct sctp_chunk *chunk = arg; 4130 4131 /* Make sure that the chunk has a valid length. 4132 * Since we don't know the chunk type, we use a general 4133 * chunkhdr structure to make a comparison. 4134 */ 4135 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4136 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4137 commands); 4138 4139 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 4140 return SCTP_DISPOSITION_DISCARD; 4141 } 4142 4143 /* 4144 * Discard the whole packet. 4145 * 4146 * Section: 8.4 2) 4147 * 4148 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4149 * silently discard the OOTB packet and take no further action. 4150 * 4151 * Verification Tag: No verification necessary 4152 * 4153 * Inputs 4154 * (endpoint, asoc, chunk) 4155 * 4156 * Outputs 4157 * (asoc, reply_msg, msg_up, timers, counters) 4158 * 4159 * The return value is the disposition of the chunk. 4160 */ 4161 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 4162 const struct sctp_association *asoc, 4163 const sctp_subtype_t type, 4164 void *arg, 4165 sctp_cmd_seq_t *commands) 4166 { 4167 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS); 4168 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4169 4170 return SCTP_DISPOSITION_CONSUME; 4171 } 4172 4173 4174 /* 4175 * The other end is violating protocol. 4176 * 4177 * Section: Not specified 4178 * Verification Tag: Not specified 4179 * Inputs 4180 * (endpoint, asoc, chunk) 4181 * 4182 * Outputs 4183 * (asoc, reply_msg, msg_up, timers, counters) 4184 * 4185 * We simply tag the chunk as a violation. The state machine will log 4186 * the violation and continue. 4187 */ 4188 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 4189 const struct sctp_association *asoc, 4190 const sctp_subtype_t type, 4191 void *arg, 4192 sctp_cmd_seq_t *commands) 4193 { 4194 struct sctp_chunk *chunk = arg; 4195 4196 /* Make sure that the chunk has a valid length. */ 4197 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4198 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4199 commands); 4200 4201 return SCTP_DISPOSITION_VIOLATION; 4202 } 4203 4204 /* 4205 * Common function to handle a protocol violation. 4206 */ 4207 static sctp_disposition_t sctp_sf_abort_violation( 4208 const struct sctp_endpoint *ep, 4209 const struct sctp_association *asoc, 4210 void *arg, 4211 sctp_cmd_seq_t *commands, 4212 const __u8 *payload, 4213 const size_t paylen) 4214 { 4215 struct sctp_packet *packet = NULL; 4216 struct sctp_chunk *chunk = arg; 4217 struct sctp_chunk *abort = NULL; 4218 4219 /* SCTP-AUTH, Section 6.3: 4220 * It should be noted that if the receiver wants to tear 4221 * down an association in an authenticated way only, the 4222 * handling of malformed packets should not result in 4223 * tearing down the association. 4224 * 4225 * This means that if we only want to abort associations 4226 * in an authenticated way (i.e AUTH+ABORT), then we 4227 * can't destroy this association just becuase the packet 4228 * was malformed. 4229 */ 4230 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4231 goto discard; 4232 4233 /* Make the abort chunk. */ 4234 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4235 if (!abort) 4236 goto nomem; 4237 4238 if (asoc) { 4239 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4240 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4241 !asoc->peer.i.init_tag) { 4242 sctp_initack_chunk_t *initack; 4243 4244 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4245 if (!sctp_chunk_length_valid(chunk, 4246 sizeof(sctp_initack_chunk_t))) 4247 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4248 else { 4249 unsigned int inittag; 4250 4251 inittag = ntohl(initack->init_hdr.init_tag); 4252 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4253 SCTP_U32(inittag)); 4254 } 4255 } 4256 4257 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4258 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4259 4260 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4261 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4262 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4263 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4264 SCTP_ERROR(ECONNREFUSED)); 4265 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4266 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4267 } else { 4268 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4269 SCTP_ERROR(ECONNABORTED)); 4270 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4271 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4272 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4273 } 4274 } else { 4275 packet = sctp_ootb_pkt_new(asoc, chunk); 4276 4277 if (!packet) 4278 goto nomem_pkt; 4279 4280 if (sctp_test_T_bit(abort)) 4281 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4282 4283 abort->skb->sk = ep->base.sk; 4284 4285 sctp_packet_append_chunk(packet, abort); 4286 4287 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4288 SCTP_PACKET(packet)); 4289 4290 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4291 } 4292 4293 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4294 4295 discard: 4296 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4297 return SCTP_DISPOSITION_ABORT; 4298 4299 nomem_pkt: 4300 sctp_chunk_free(abort); 4301 nomem: 4302 return SCTP_DISPOSITION_NOMEM; 4303 } 4304 4305 /* 4306 * Handle a protocol violation when the chunk length is invalid. 4307 * "Invalid" length is identified as smaller than the minimal length a 4308 * given chunk can be. For example, a SACK chunk has invalid length 4309 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4310 * 4311 * We inform the other end by sending an ABORT with a Protocol Violation 4312 * error code. 4313 * 4314 * Section: Not specified 4315 * Verification Tag: Nothing to do 4316 * Inputs 4317 * (endpoint, asoc, chunk) 4318 * 4319 * Outputs 4320 * (reply_msg, msg_up, counters) 4321 * 4322 * Generate an ABORT chunk and terminate the association. 4323 */ 4324 static sctp_disposition_t sctp_sf_violation_chunklen( 4325 const struct sctp_endpoint *ep, 4326 const struct sctp_association *asoc, 4327 const sctp_subtype_t type, 4328 void *arg, 4329 sctp_cmd_seq_t *commands) 4330 { 4331 static const char err_str[]="The following chunk had invalid length:"; 4332 4333 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4334 sizeof(err_str)); 4335 } 4336 4337 /* 4338 * Handle a protocol violation when the parameter length is invalid. 4339 * "Invalid" length is identified as smaller than the minimal length a 4340 * given parameter can be. 4341 */ 4342 static sctp_disposition_t sctp_sf_violation_paramlen( 4343 const struct sctp_endpoint *ep, 4344 const struct sctp_association *asoc, 4345 const sctp_subtype_t type, 4346 void *arg, void *ext, 4347 sctp_cmd_seq_t *commands) 4348 { 4349 struct sctp_chunk *chunk = arg; 4350 struct sctp_paramhdr *param = ext; 4351 struct sctp_chunk *abort = NULL; 4352 4353 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4354 goto discard; 4355 4356 /* Make the abort chunk. */ 4357 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4358 if (!abort) 4359 goto nomem; 4360 4361 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4362 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4363 4364 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4365 SCTP_ERROR(ECONNABORTED)); 4366 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4367 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4368 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4369 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4370 4371 discard: 4372 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4373 return SCTP_DISPOSITION_ABORT; 4374 nomem: 4375 return SCTP_DISPOSITION_NOMEM; 4376 } 4377 4378 /* Handle a protocol violation when the peer trying to advance the 4379 * cumulative tsn ack to a point beyond the max tsn currently sent. 4380 * 4381 * We inform the other end by sending an ABORT with a Protocol Violation 4382 * error code. 4383 */ 4384 static sctp_disposition_t sctp_sf_violation_ctsn( 4385 const struct sctp_endpoint *ep, 4386 const struct sctp_association *asoc, 4387 const sctp_subtype_t type, 4388 void *arg, 4389 sctp_cmd_seq_t *commands) 4390 { 4391 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4392 4393 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4394 sizeof(err_str)); 4395 } 4396 4397 /* Handle protocol violation of an invalid chunk bundling. For example, 4398 * when we have an association and we recieve bundled INIT-ACK, or 4399 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4400 * statement from the specs. Additinally, there might be an attacker 4401 * on the path and we may not want to continue this communication. 4402 */ 4403 static sctp_disposition_t sctp_sf_violation_chunk( 4404 const struct sctp_endpoint *ep, 4405 const struct sctp_association *asoc, 4406 const sctp_subtype_t type, 4407 void *arg, 4408 sctp_cmd_seq_t *commands) 4409 { 4410 static const char err_str[]="The following chunk violates protocol:"; 4411 4412 if (!asoc) 4413 return sctp_sf_violation(ep, asoc, type, arg, commands); 4414 4415 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4416 sizeof(err_str)); 4417 } 4418 /*************************************************************************** 4419 * These are the state functions for handling primitive (Section 10) events. 4420 ***************************************************************************/ 4421 /* 4422 * sctp_sf_do_prm_asoc 4423 * 4424 * Section: 10.1 ULP-to-SCTP 4425 * B) Associate 4426 * 4427 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4428 * outbound stream count) 4429 * -> association id [,destination transport addr list] [,outbound stream 4430 * count] 4431 * 4432 * This primitive allows the upper layer to initiate an association to a 4433 * specific peer endpoint. 4434 * 4435 * The peer endpoint shall be specified by one of the transport addresses 4436 * which defines the endpoint (see Section 1.4). If the local SCTP 4437 * instance has not been initialized, the ASSOCIATE is considered an 4438 * error. 4439 * [This is not relevant for the kernel implementation since we do all 4440 * initialization at boot time. It we hadn't initialized we wouldn't 4441 * get anywhere near this code.] 4442 * 4443 * An association id, which is a local handle to the SCTP association, 4444 * will be returned on successful establishment of the association. If 4445 * SCTP is not able to open an SCTP association with the peer endpoint, 4446 * an error is returned. 4447 * [In the kernel implementation, the struct sctp_association needs to 4448 * be created BEFORE causing this primitive to run.] 4449 * 4450 * Other association parameters may be returned, including the 4451 * complete destination transport addresses of the peer as well as the 4452 * outbound stream count of the local endpoint. One of the transport 4453 * address from the returned destination addresses will be selected by 4454 * the local endpoint as default primary path for sending SCTP packets 4455 * to this peer. The returned "destination transport addr list" can 4456 * be used by the ULP to change the default primary path or to force 4457 * sending a packet to a specific transport address. [All of this 4458 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4459 * function.] 4460 * 4461 * Mandatory attributes: 4462 * 4463 * o local SCTP instance name - obtained from the INITIALIZE operation. 4464 * [This is the argument asoc.] 4465 * o destination transport addr - specified as one of the transport 4466 * addresses of the peer endpoint with which the association is to be 4467 * established. 4468 * [This is asoc->peer.active_path.] 4469 * o outbound stream count - the number of outbound streams the ULP 4470 * would like to open towards this peer endpoint. 4471 * [BUG: This is not currently implemented.] 4472 * Optional attributes: 4473 * 4474 * None. 4475 * 4476 * The return value is a disposition. 4477 */ 4478 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 4479 const struct sctp_association *asoc, 4480 const sctp_subtype_t type, 4481 void *arg, 4482 sctp_cmd_seq_t *commands) 4483 { 4484 struct sctp_chunk *repl; 4485 struct sctp_association* my_asoc; 4486 4487 /* The comment below says that we enter COOKIE-WAIT AFTER 4488 * sending the INIT, but that doesn't actually work in our 4489 * implementation... 4490 */ 4491 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4492 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4493 4494 /* RFC 2960 5.1 Normal Establishment of an Association 4495 * 4496 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4497 * must provide its Verification Tag (Tag_A) in the Initiate 4498 * Tag field. Tag_A SHOULD be a random number in the range of 4499 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4500 */ 4501 4502 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4503 if (!repl) 4504 goto nomem; 4505 4506 /* Cast away the const modifier, as we want to just 4507 * rerun it through as a sideffect. 4508 */ 4509 my_asoc = (struct sctp_association *)asoc; 4510 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4511 4512 /* Choose transport for INIT. */ 4513 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4514 SCTP_CHUNK(repl)); 4515 4516 /* After sending the INIT, "A" starts the T1-init timer and 4517 * enters the COOKIE-WAIT state. 4518 */ 4519 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4520 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4521 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4522 return SCTP_DISPOSITION_CONSUME; 4523 4524 nomem: 4525 return SCTP_DISPOSITION_NOMEM; 4526 } 4527 4528 /* 4529 * Process the SEND primitive. 4530 * 4531 * Section: 10.1 ULP-to-SCTP 4532 * E) Send 4533 * 4534 * Format: SEND(association id, buffer address, byte count [,context] 4535 * [,stream id] [,life time] [,destination transport address] 4536 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4537 * -> result 4538 * 4539 * This is the main method to send user data via SCTP. 4540 * 4541 * Mandatory attributes: 4542 * 4543 * o association id - local handle to the SCTP association 4544 * 4545 * o buffer address - the location where the user message to be 4546 * transmitted is stored; 4547 * 4548 * o byte count - The size of the user data in number of bytes; 4549 * 4550 * Optional attributes: 4551 * 4552 * o context - an optional 32 bit integer that will be carried in the 4553 * sending failure notification to the ULP if the transportation of 4554 * this User Message fails. 4555 * 4556 * o stream id - to indicate which stream to send the data on. If not 4557 * specified, stream 0 will be used. 4558 * 4559 * o life time - specifies the life time of the user data. The user data 4560 * will not be sent by SCTP after the life time expires. This 4561 * parameter can be used to avoid efforts to transmit stale 4562 * user messages. SCTP notifies the ULP if the data cannot be 4563 * initiated to transport (i.e. sent to the destination via SCTP's 4564 * send primitive) within the life time variable. However, the 4565 * user data will be transmitted if SCTP has attempted to transmit a 4566 * chunk before the life time expired. 4567 * 4568 * o destination transport address - specified as one of the destination 4569 * transport addresses of the peer endpoint to which this packet 4570 * should be sent. Whenever possible, SCTP should use this destination 4571 * transport address for sending the packets, instead of the current 4572 * primary path. 4573 * 4574 * o unorder flag - this flag, if present, indicates that the user 4575 * would like the data delivered in an unordered fashion to the peer 4576 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4577 * message). 4578 * 4579 * o no-bundle flag - instructs SCTP not to bundle this user data with 4580 * other outbound DATA chunks. SCTP MAY still bundle even when 4581 * this flag is present, when faced with network congestion. 4582 * 4583 * o payload protocol-id - A 32 bit unsigned integer that is to be 4584 * passed to the peer indicating the type of payload protocol data 4585 * being transmitted. This value is passed as opaque data by SCTP. 4586 * 4587 * The return value is the disposition. 4588 */ 4589 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 4590 const struct sctp_association *asoc, 4591 const sctp_subtype_t type, 4592 void *arg, 4593 sctp_cmd_seq_t *commands) 4594 { 4595 struct sctp_datamsg *msg = arg; 4596 4597 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4598 return SCTP_DISPOSITION_CONSUME; 4599 } 4600 4601 /* 4602 * Process the SHUTDOWN primitive. 4603 * 4604 * Section: 10.1: 4605 * C) Shutdown 4606 * 4607 * Format: SHUTDOWN(association id) 4608 * -> result 4609 * 4610 * Gracefully closes an association. Any locally queued user data 4611 * will be delivered to the peer. The association will be terminated only 4612 * after the peer acknowledges all the SCTP packets sent. A success code 4613 * will be returned on successful termination of the association. If 4614 * attempting to terminate the association results in a failure, an error 4615 * code shall be returned. 4616 * 4617 * Mandatory attributes: 4618 * 4619 * o association id - local handle to the SCTP association 4620 * 4621 * Optional attributes: 4622 * 4623 * None. 4624 * 4625 * The return value is the disposition. 4626 */ 4627 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4628 const struct sctp_endpoint *ep, 4629 const struct sctp_association *asoc, 4630 const sctp_subtype_t type, 4631 void *arg, 4632 sctp_cmd_seq_t *commands) 4633 { 4634 int disposition; 4635 4636 /* From 9.2 Shutdown of an Association 4637 * Upon receipt of the SHUTDOWN primitive from its upper 4638 * layer, the endpoint enters SHUTDOWN-PENDING state and 4639 * remains there until all outstanding data has been 4640 * acknowledged by its peer. The endpoint accepts no new data 4641 * from its upper layer, but retransmits data to the far end 4642 * if necessary to fill gaps. 4643 */ 4644 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4645 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4646 4647 disposition = SCTP_DISPOSITION_CONSUME; 4648 if (sctp_outq_is_empty(&asoc->outqueue)) { 4649 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4650 arg, commands); 4651 } 4652 return disposition; 4653 } 4654 4655 /* 4656 * Process the ABORT primitive. 4657 * 4658 * Section: 10.1: 4659 * C) Abort 4660 * 4661 * Format: Abort(association id [, cause code]) 4662 * -> result 4663 * 4664 * Ungracefully closes an association. Any locally queued user data 4665 * will be discarded and an ABORT chunk is sent to the peer. A success code 4666 * will be returned on successful abortion of the association. If 4667 * attempting to abort the association results in a failure, an error 4668 * code shall be returned. 4669 * 4670 * Mandatory attributes: 4671 * 4672 * o association id - local handle to the SCTP association 4673 * 4674 * Optional attributes: 4675 * 4676 * o cause code - reason of the abort to be passed to the peer 4677 * 4678 * None. 4679 * 4680 * The return value is the disposition. 4681 */ 4682 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4683 const struct sctp_endpoint *ep, 4684 const struct sctp_association *asoc, 4685 const sctp_subtype_t type, 4686 void *arg, 4687 sctp_cmd_seq_t *commands) 4688 { 4689 /* From 9.1 Abort of an Association 4690 * Upon receipt of the ABORT primitive from its upper 4691 * layer, the endpoint enters CLOSED state and 4692 * discard all outstanding data has been 4693 * acknowledged by its peer. The endpoint accepts no new data 4694 * from its upper layer, but retransmits data to the far end 4695 * if necessary to fill gaps. 4696 */ 4697 struct sctp_chunk *abort = arg; 4698 sctp_disposition_t retval; 4699 4700 retval = SCTP_DISPOSITION_CONSUME; 4701 4702 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4703 4704 /* Even if we can't send the ABORT due to low memory delete the 4705 * TCB. This is a departure from our typical NOMEM handling. 4706 */ 4707 4708 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4709 SCTP_ERROR(ECONNABORTED)); 4710 /* Delete the established association. */ 4711 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4712 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4713 4714 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4715 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4716 4717 return retval; 4718 } 4719 4720 /* We tried an illegal operation on an association which is closed. */ 4721 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4722 const struct sctp_association *asoc, 4723 const sctp_subtype_t type, 4724 void *arg, 4725 sctp_cmd_seq_t *commands) 4726 { 4727 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4728 return SCTP_DISPOSITION_CONSUME; 4729 } 4730 4731 /* We tried an illegal operation on an association which is shutting 4732 * down. 4733 */ 4734 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4735 const struct sctp_association *asoc, 4736 const sctp_subtype_t type, 4737 void *arg, 4738 sctp_cmd_seq_t *commands) 4739 { 4740 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4741 SCTP_ERROR(-ESHUTDOWN)); 4742 return SCTP_DISPOSITION_CONSUME; 4743 } 4744 4745 /* 4746 * sctp_cookie_wait_prm_shutdown 4747 * 4748 * Section: 4 Note: 2 4749 * Verification Tag: 4750 * Inputs 4751 * (endpoint, asoc) 4752 * 4753 * The RFC does not explicitly address this issue, but is the route through the 4754 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4755 * 4756 * Outputs 4757 * (timers) 4758 */ 4759 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4760 const struct sctp_endpoint *ep, 4761 const struct sctp_association *asoc, 4762 const sctp_subtype_t type, 4763 void *arg, 4764 sctp_cmd_seq_t *commands) 4765 { 4766 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4767 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4768 4769 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4770 SCTP_STATE(SCTP_STATE_CLOSED)); 4771 4772 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4773 4774 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4775 4776 return SCTP_DISPOSITION_DELETE_TCB; 4777 } 4778 4779 /* 4780 * sctp_cookie_echoed_prm_shutdown 4781 * 4782 * Section: 4 Note: 2 4783 * Verification Tag: 4784 * Inputs 4785 * (endpoint, asoc) 4786 * 4787 * The RFC does not explcitly address this issue, but is the route through the 4788 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4789 * 4790 * Outputs 4791 * (timers) 4792 */ 4793 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4794 const struct sctp_endpoint *ep, 4795 const struct sctp_association *asoc, 4796 const sctp_subtype_t type, 4797 void *arg, sctp_cmd_seq_t *commands) 4798 { 4799 /* There is a single T1 timer, so we should be able to use 4800 * common function with the COOKIE-WAIT state. 4801 */ 4802 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4803 } 4804 4805 /* 4806 * sctp_sf_cookie_wait_prm_abort 4807 * 4808 * Section: 4 Note: 2 4809 * Verification Tag: 4810 * Inputs 4811 * (endpoint, asoc) 4812 * 4813 * The RFC does not explicitly address this issue, but is the route through the 4814 * state table when someone issues an abort while in COOKIE_WAIT state. 4815 * 4816 * Outputs 4817 * (timers) 4818 */ 4819 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4820 const struct sctp_endpoint *ep, 4821 const struct sctp_association *asoc, 4822 const sctp_subtype_t type, 4823 void *arg, 4824 sctp_cmd_seq_t *commands) 4825 { 4826 struct sctp_chunk *abort = arg; 4827 sctp_disposition_t retval; 4828 4829 /* Stop T1-init timer */ 4830 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4831 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4832 retval = SCTP_DISPOSITION_CONSUME; 4833 4834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4835 4836 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4837 SCTP_STATE(SCTP_STATE_CLOSED)); 4838 4839 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4840 4841 /* Even if we can't send the ABORT due to low memory delete the 4842 * TCB. This is a departure from our typical NOMEM handling. 4843 */ 4844 4845 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4846 SCTP_ERROR(ECONNREFUSED)); 4847 /* Delete the established association. */ 4848 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4849 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4850 4851 return retval; 4852 } 4853 4854 /* 4855 * sctp_sf_cookie_echoed_prm_abort 4856 * 4857 * Section: 4 Note: 3 4858 * Verification Tag: 4859 * Inputs 4860 * (endpoint, asoc) 4861 * 4862 * The RFC does not explcitly address this issue, but is the route through the 4863 * state table when someone issues an abort while in COOKIE_ECHOED state. 4864 * 4865 * Outputs 4866 * (timers) 4867 */ 4868 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4869 const struct sctp_endpoint *ep, 4870 const struct sctp_association *asoc, 4871 const sctp_subtype_t type, 4872 void *arg, 4873 sctp_cmd_seq_t *commands) 4874 { 4875 /* There is a single T1 timer, so we should be able to use 4876 * common function with the COOKIE-WAIT state. 4877 */ 4878 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4879 } 4880 4881 /* 4882 * sctp_sf_shutdown_pending_prm_abort 4883 * 4884 * Inputs 4885 * (endpoint, asoc) 4886 * 4887 * The RFC does not explicitly address this issue, but is the route through the 4888 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4889 * 4890 * Outputs 4891 * (timers) 4892 */ 4893 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4894 const struct sctp_endpoint *ep, 4895 const struct sctp_association *asoc, 4896 const sctp_subtype_t type, 4897 void *arg, 4898 sctp_cmd_seq_t *commands) 4899 { 4900 /* Stop the T5-shutdown guard timer. */ 4901 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4902 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4903 4904 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4905 } 4906 4907 /* 4908 * sctp_sf_shutdown_sent_prm_abort 4909 * 4910 * Inputs 4911 * (endpoint, asoc) 4912 * 4913 * The RFC does not explicitly address this issue, but is the route through the 4914 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4915 * 4916 * Outputs 4917 * (timers) 4918 */ 4919 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4920 const struct sctp_endpoint *ep, 4921 const struct sctp_association *asoc, 4922 const sctp_subtype_t type, 4923 void *arg, 4924 sctp_cmd_seq_t *commands) 4925 { 4926 /* Stop the T2-shutdown timer. */ 4927 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4928 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4929 4930 /* Stop the T5-shutdown guard timer. */ 4931 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4932 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4933 4934 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4935 } 4936 4937 /* 4938 * sctp_sf_cookie_echoed_prm_abort 4939 * 4940 * Inputs 4941 * (endpoint, asoc) 4942 * 4943 * The RFC does not explcitly address this issue, but is the route through the 4944 * state table when someone issues an abort while in COOKIE_ECHOED state. 4945 * 4946 * Outputs 4947 * (timers) 4948 */ 4949 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4950 const struct sctp_endpoint *ep, 4951 const struct sctp_association *asoc, 4952 const sctp_subtype_t type, 4953 void *arg, 4954 sctp_cmd_seq_t *commands) 4955 { 4956 /* The same T2 timer, so we should be able to use 4957 * common function with the SHUTDOWN-SENT state. 4958 */ 4959 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4960 } 4961 4962 /* 4963 * Process the REQUESTHEARTBEAT primitive 4964 * 4965 * 10.1 ULP-to-SCTP 4966 * J) Request Heartbeat 4967 * 4968 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4969 * 4970 * -> result 4971 * 4972 * Instructs the local endpoint to perform a HeartBeat on the specified 4973 * destination transport address of the given association. The returned 4974 * result should indicate whether the transmission of the HEARTBEAT 4975 * chunk to the destination address is successful. 4976 * 4977 * Mandatory attributes: 4978 * 4979 * o association id - local handle to the SCTP association 4980 * 4981 * o destination transport address - the transport address of the 4982 * association on which a heartbeat should be issued. 4983 */ 4984 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4985 const struct sctp_endpoint *ep, 4986 const struct sctp_association *asoc, 4987 const sctp_subtype_t type, 4988 void *arg, 4989 sctp_cmd_seq_t *commands) 4990 { 4991 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 4992 (struct sctp_transport *)arg, commands)) 4993 return SCTP_DISPOSITION_NOMEM; 4994 4995 /* 4996 * RFC 2960 (bis), section 8.3 4997 * 4998 * D) Request an on-demand HEARTBEAT on a specific destination 4999 * transport address of a given association. 5000 * 5001 * The endpoint should increment the respective error counter of 5002 * the destination transport address each time a HEARTBEAT is sent 5003 * to that address and not acknowledged within one RTO. 5004 * 5005 */ 5006 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5007 SCTP_TRANSPORT(arg)); 5008 return SCTP_DISPOSITION_CONSUME; 5009 } 5010 5011 /* 5012 * ADDIP Section 4.1 ASCONF Chunk Procedures 5013 * When an endpoint has an ASCONF signaled change to be sent to the 5014 * remote endpoint it should do A1 to A9 5015 */ 5016 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 5017 const struct sctp_association *asoc, 5018 const sctp_subtype_t type, 5019 void *arg, 5020 sctp_cmd_seq_t *commands) 5021 { 5022 struct sctp_chunk *chunk = arg; 5023 5024 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5025 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5026 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5027 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5028 return SCTP_DISPOSITION_CONSUME; 5029 } 5030 5031 /* 5032 * Ignore the primitive event 5033 * 5034 * The return value is the disposition of the primitive. 5035 */ 5036 sctp_disposition_t sctp_sf_ignore_primitive( 5037 const struct sctp_endpoint *ep, 5038 const struct sctp_association *asoc, 5039 const sctp_subtype_t type, 5040 void *arg, 5041 sctp_cmd_seq_t *commands) 5042 { 5043 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 5044 return SCTP_DISPOSITION_DISCARD; 5045 } 5046 5047 /*************************************************************************** 5048 * These are the state functions for the OTHER events. 5049 ***************************************************************************/ 5050 5051 /* 5052 * Start the shutdown negotiation. 5053 * 5054 * From Section 9.2: 5055 * Once all its outstanding data has been acknowledged, the endpoint 5056 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5057 * TSN Ack field the last sequential TSN it has received from the peer. 5058 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5059 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5060 * with the updated last sequential TSN received from its peer. 5061 * 5062 * The return value is the disposition. 5063 */ 5064 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5065 const struct sctp_endpoint *ep, 5066 const struct sctp_association *asoc, 5067 const sctp_subtype_t type, 5068 void *arg, 5069 sctp_cmd_seq_t *commands) 5070 { 5071 struct sctp_chunk *reply; 5072 5073 /* Once all its outstanding data has been acknowledged, the 5074 * endpoint shall send a SHUTDOWN chunk to its peer including 5075 * in the Cumulative TSN Ack field the last sequential TSN it 5076 * has received from the peer. 5077 */ 5078 reply = sctp_make_shutdown(asoc, NULL); 5079 if (!reply) 5080 goto nomem; 5081 5082 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5083 * T2-shutdown timer. 5084 */ 5085 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5086 5087 /* It shall then start the T2-shutdown timer */ 5088 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5089 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5090 5091 /* RFC 4960 Section 9.2 5092 * The sender of the SHUTDOWN MAY also start an overall guard timer 5093 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5094 */ 5095 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5096 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5097 5098 if (asoc->autoclose) 5099 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5100 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5101 5102 /* and enter the SHUTDOWN-SENT state. */ 5103 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5104 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5105 5106 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5107 * 5108 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5109 * or SHUTDOWN-ACK. 5110 */ 5111 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5112 5113 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5114 5115 return SCTP_DISPOSITION_CONSUME; 5116 5117 nomem: 5118 return SCTP_DISPOSITION_NOMEM; 5119 } 5120 5121 /* 5122 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5123 * 5124 * From Section 9.2: 5125 * 5126 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5127 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5128 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5129 * endpoint must re-send the SHUTDOWN ACK. 5130 * 5131 * The return value is the disposition. 5132 */ 5133 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5134 const struct sctp_endpoint *ep, 5135 const struct sctp_association *asoc, 5136 const sctp_subtype_t type, 5137 void *arg, 5138 sctp_cmd_seq_t *commands) 5139 { 5140 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5141 struct sctp_chunk *reply; 5142 5143 /* There are 2 ways of getting here: 5144 * 1) called in response to a SHUTDOWN chunk 5145 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5146 * 5147 * For the case (2), the arg parameter is set to NULL. We need 5148 * to check that we have a chunk before accessing it's fields. 5149 */ 5150 if (chunk) { 5151 if (!sctp_vtag_verify(chunk, asoc)) 5152 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 5153 5154 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5155 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5156 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 5157 commands); 5158 } 5159 5160 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5161 * shall send a SHUTDOWN ACK ... 5162 */ 5163 reply = sctp_make_shutdown_ack(asoc, chunk); 5164 if (!reply) 5165 goto nomem; 5166 5167 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5168 * the T2-shutdown timer. 5169 */ 5170 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5171 5172 /* and start/restart a T2-shutdown timer of its own, */ 5173 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5174 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5175 5176 if (asoc->autoclose) 5177 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5178 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5179 5180 /* Enter the SHUTDOWN-ACK-SENT state. */ 5181 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5182 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5183 5184 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5185 * 5186 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5187 * or SHUTDOWN-ACK. 5188 */ 5189 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5190 5191 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5192 5193 return SCTP_DISPOSITION_CONSUME; 5194 5195 nomem: 5196 return SCTP_DISPOSITION_NOMEM; 5197 } 5198 5199 /* 5200 * Ignore the event defined as other 5201 * 5202 * The return value is the disposition of the event. 5203 */ 5204 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 5205 const struct sctp_association *asoc, 5206 const sctp_subtype_t type, 5207 void *arg, 5208 sctp_cmd_seq_t *commands) 5209 { 5210 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5211 return SCTP_DISPOSITION_DISCARD; 5212 } 5213 5214 /************************************************************ 5215 * These are the state functions for handling timeout events. 5216 ************************************************************/ 5217 5218 /* 5219 * RTX Timeout 5220 * 5221 * Section: 6.3.3 Handle T3-rtx Expiration 5222 * 5223 * Whenever the retransmission timer T3-rtx expires for a destination 5224 * address, do the following: 5225 * [See below] 5226 * 5227 * The return value is the disposition of the chunk. 5228 */ 5229 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 5230 const struct sctp_association *asoc, 5231 const sctp_subtype_t type, 5232 void *arg, 5233 sctp_cmd_seq_t *commands) 5234 { 5235 struct sctp_transport *transport = arg; 5236 5237 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS); 5238 5239 if (asoc->overall_error_count >= asoc->max_retrans) { 5240 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5241 SCTP_ERROR(ETIMEDOUT)); 5242 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5243 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5244 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5245 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5246 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5247 return SCTP_DISPOSITION_DELETE_TCB; 5248 } 5249 5250 /* E1) For the destination address for which the timer 5251 * expires, adjust its ssthresh with rules defined in Section 5252 * 7.2.3 and set the cwnd <- MTU. 5253 */ 5254 5255 /* E2) For the destination address for which the timer 5256 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5257 * maximum value discussed in rule C7 above (RTO.max) may be 5258 * used to provide an upper bound to this doubling operation. 5259 */ 5260 5261 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5262 * outstanding DATA chunks for the address for which the 5263 * T3-rtx has expired will fit into a single packet, subject 5264 * to the MTU constraint for the path corresponding to the 5265 * destination transport address to which the retransmission 5266 * is being sent (this may be different from the address for 5267 * which the timer expires [see Section 6.4]). Call this 5268 * value K. Bundle and retransmit those K DATA chunks in a 5269 * single packet to the destination endpoint. 5270 * 5271 * Note: Any DATA chunks that were sent to the address for 5272 * which the T3-rtx timer expired but did not fit in one MTU 5273 * (rule E3 above), should be marked for retransmission and 5274 * sent as soon as cwnd allows (normally when a SACK arrives). 5275 */ 5276 5277 /* Do some failure management (Section 8.2). */ 5278 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5279 5280 /* NB: Rules E4 and F1 are implicit in R1. */ 5281 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5282 5283 return SCTP_DISPOSITION_CONSUME; 5284 } 5285 5286 /* 5287 * Generate delayed SACK on timeout 5288 * 5289 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5290 * 5291 * The guidelines on delayed acknowledgement algorithm specified in 5292 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5293 * acknowledgement SHOULD be generated for at least every second packet 5294 * (not every second DATA chunk) received, and SHOULD be generated 5295 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5296 * some situations it may be beneficial for an SCTP transmitter to be 5297 * more conservative than the algorithms detailed in this document 5298 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5299 * the following algorithms allow. 5300 */ 5301 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 5302 const struct sctp_association *asoc, 5303 const sctp_subtype_t type, 5304 void *arg, 5305 sctp_cmd_seq_t *commands) 5306 { 5307 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS); 5308 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5309 return SCTP_DISPOSITION_CONSUME; 5310 } 5311 5312 /* 5313 * sctp_sf_t1_init_timer_expire 5314 * 5315 * Section: 4 Note: 2 5316 * Verification Tag: 5317 * Inputs 5318 * (endpoint, asoc) 5319 * 5320 * RFC 2960 Section 4 Notes 5321 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5322 * and re-start the T1-init timer without changing state. This MUST 5323 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5324 * endpoint MUST abort the initialization process and report the 5325 * error to SCTP user. 5326 * 5327 * Outputs 5328 * (timers, events) 5329 * 5330 */ 5331 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 5332 const struct sctp_association *asoc, 5333 const sctp_subtype_t type, 5334 void *arg, 5335 sctp_cmd_seq_t *commands) 5336 { 5337 struct sctp_chunk *repl = NULL; 5338 struct sctp_bind_addr *bp; 5339 int attempts = asoc->init_err_counter + 1; 5340 5341 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5342 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS); 5343 5344 if (attempts <= asoc->max_init_attempts) { 5345 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5346 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5347 if (!repl) 5348 return SCTP_DISPOSITION_NOMEM; 5349 5350 /* Choose transport for INIT. */ 5351 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5352 SCTP_CHUNK(repl)); 5353 5354 /* Issue a sideeffect to do the needed accounting. */ 5355 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5356 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5357 5358 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5359 } else { 5360 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5361 " max_init_attempts: %d\n", 5362 attempts, asoc->max_init_attempts); 5363 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5364 SCTP_ERROR(ETIMEDOUT)); 5365 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5366 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5367 return SCTP_DISPOSITION_DELETE_TCB; 5368 } 5369 5370 return SCTP_DISPOSITION_CONSUME; 5371 } 5372 5373 /* 5374 * sctp_sf_t1_cookie_timer_expire 5375 * 5376 * Section: 4 Note: 2 5377 * Verification Tag: 5378 * Inputs 5379 * (endpoint, asoc) 5380 * 5381 * RFC 2960 Section 4 Notes 5382 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5383 * COOKIE ECHO and re-start the T1-cookie timer without changing 5384 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5385 * After that, the endpoint MUST abort the initialization process and 5386 * report the error to SCTP user. 5387 * 5388 * Outputs 5389 * (timers, events) 5390 * 5391 */ 5392 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 5393 const struct sctp_association *asoc, 5394 const sctp_subtype_t type, 5395 void *arg, 5396 sctp_cmd_seq_t *commands) 5397 { 5398 struct sctp_chunk *repl = NULL; 5399 int attempts = asoc->init_err_counter + 1; 5400 5401 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5402 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS); 5403 5404 if (attempts <= asoc->max_init_attempts) { 5405 repl = sctp_make_cookie_echo(asoc, NULL); 5406 if (!repl) 5407 return SCTP_DISPOSITION_NOMEM; 5408 5409 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5410 SCTP_CHUNK(repl)); 5411 /* Issue a sideeffect to do the needed accounting. */ 5412 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5413 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5414 5415 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5416 } else { 5417 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5418 SCTP_ERROR(ETIMEDOUT)); 5419 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5420 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5421 return SCTP_DISPOSITION_DELETE_TCB; 5422 } 5423 5424 return SCTP_DISPOSITION_CONSUME; 5425 } 5426 5427 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5428 * with the updated last sequential TSN received from its peer. 5429 * 5430 * An endpoint should limit the number of retransmissions of the 5431 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5432 * If this threshold is exceeded the endpoint should destroy the TCB and 5433 * MUST report the peer endpoint unreachable to the upper layer (and 5434 * thus the association enters the CLOSED state). The reception of any 5435 * packet from its peer (i.e. as the peer sends all of its queued DATA 5436 * chunks) should clear the endpoint's retransmission count and restart 5437 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5438 * all of its queued DATA chunks that have not yet been sent. 5439 */ 5440 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 5441 const struct sctp_association *asoc, 5442 const sctp_subtype_t type, 5443 void *arg, 5444 sctp_cmd_seq_t *commands) 5445 { 5446 struct sctp_chunk *reply = NULL; 5447 5448 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 5449 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5450 5451 ((struct sctp_association *)asoc)->shutdown_retries++; 5452 5453 if (asoc->overall_error_count >= asoc->max_retrans) { 5454 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5455 SCTP_ERROR(ETIMEDOUT)); 5456 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5457 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5458 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5459 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5460 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5461 return SCTP_DISPOSITION_DELETE_TCB; 5462 } 5463 5464 switch (asoc->state) { 5465 case SCTP_STATE_SHUTDOWN_SENT: 5466 reply = sctp_make_shutdown(asoc, NULL); 5467 break; 5468 5469 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5470 reply = sctp_make_shutdown_ack(asoc, NULL); 5471 break; 5472 5473 default: 5474 BUG(); 5475 break; 5476 } 5477 5478 if (!reply) 5479 goto nomem; 5480 5481 /* Do some failure management (Section 8.2). 5482 * If we remove the transport an SHUTDOWN was last sent to, don't 5483 * do failure management. 5484 */ 5485 if (asoc->shutdown_last_sent_to) 5486 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5487 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5488 5489 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5490 * the T2-shutdown timer. 5491 */ 5492 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5493 5494 /* Restart the T2-shutdown timer. */ 5495 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5496 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5497 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5498 return SCTP_DISPOSITION_CONSUME; 5499 5500 nomem: 5501 return SCTP_DISPOSITION_NOMEM; 5502 } 5503 5504 /* 5505 * ADDIP Section 4.1 ASCONF CHunk Procedures 5506 * If the T4 RTO timer expires the endpoint should do B1 to B5 5507 */ 5508 sctp_disposition_t sctp_sf_t4_timer_expire( 5509 const struct sctp_endpoint *ep, 5510 const struct sctp_association *asoc, 5511 const sctp_subtype_t type, 5512 void *arg, 5513 sctp_cmd_seq_t *commands) 5514 { 5515 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5516 struct sctp_transport *transport = chunk->transport; 5517 5518 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS); 5519 5520 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5521 * detection on the appropriate destination address as defined in 5522 * RFC2960 [5] section 8.1 and 8.2. 5523 */ 5524 if (transport) 5525 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5526 SCTP_TRANSPORT(transport)); 5527 5528 /* Reconfig T4 timer and transport. */ 5529 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5530 5531 /* ADDIP 4.1 B2) Increment the association error counters and perform 5532 * endpoint failure detection on the association as defined in 5533 * RFC2960 [5] section 8.1 and 8.2. 5534 * association error counter is incremented in SCTP_CMD_STRIKE. 5535 */ 5536 if (asoc->overall_error_count >= asoc->max_retrans) { 5537 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5538 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5539 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5540 SCTP_ERROR(ETIMEDOUT)); 5541 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5542 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5543 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5544 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5545 return SCTP_DISPOSITION_ABORT; 5546 } 5547 5548 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5549 * the ASCONF chunk was sent by doubling the RTO timer value. 5550 * This is done in SCTP_CMD_STRIKE. 5551 */ 5552 5553 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5554 * choose an alternate destination address (please refer to RFC2960 5555 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5556 * chunk, it MUST be the same (including its serial number) as the last 5557 * ASCONF sent. 5558 */ 5559 sctp_chunk_hold(asoc->addip_last_asconf); 5560 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5561 SCTP_CHUNK(asoc->addip_last_asconf)); 5562 5563 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5564 * destination is selected, then the RTO used will be that of the new 5565 * destination address. 5566 */ 5567 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5568 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5569 5570 return SCTP_DISPOSITION_CONSUME; 5571 } 5572 5573 /* sctpimpguide-05 Section 2.12.2 5574 * The sender of the SHUTDOWN MAY also start an overall guard timer 5575 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5576 * At the expiration of this timer the sender SHOULD abort the association 5577 * by sending an ABORT chunk. 5578 */ 5579 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 5580 const struct sctp_association *asoc, 5581 const sctp_subtype_t type, 5582 void *arg, 5583 sctp_cmd_seq_t *commands) 5584 { 5585 struct sctp_chunk *reply = NULL; 5586 5587 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5588 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5589 5590 reply = sctp_make_abort(asoc, NULL, 0); 5591 if (!reply) 5592 goto nomem; 5593 5594 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5595 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5596 SCTP_ERROR(ETIMEDOUT)); 5597 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5598 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5599 5600 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5601 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5602 5603 return SCTP_DISPOSITION_DELETE_TCB; 5604 nomem: 5605 return SCTP_DISPOSITION_NOMEM; 5606 } 5607 5608 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5609 * the association is automatically closed by starting the shutdown process. 5610 * The work that needs to be done is same as when SHUTDOWN is initiated by 5611 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5612 */ 5613 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5614 const struct sctp_endpoint *ep, 5615 const struct sctp_association *asoc, 5616 const sctp_subtype_t type, 5617 void *arg, 5618 sctp_cmd_seq_t *commands) 5619 { 5620 int disposition; 5621 5622 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS); 5623 5624 /* From 9.2 Shutdown of an Association 5625 * Upon receipt of the SHUTDOWN primitive from its upper 5626 * layer, the endpoint enters SHUTDOWN-PENDING state and 5627 * remains there until all outstanding data has been 5628 * acknowledged by its peer. The endpoint accepts no new data 5629 * from its upper layer, but retransmits data to the far end 5630 * if necessary to fill gaps. 5631 */ 5632 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5633 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5634 5635 disposition = SCTP_DISPOSITION_CONSUME; 5636 if (sctp_outq_is_empty(&asoc->outqueue)) { 5637 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 5638 arg, commands); 5639 } 5640 return disposition; 5641 } 5642 5643 /***************************************************************************** 5644 * These are sa state functions which could apply to all types of events. 5645 ****************************************************************************/ 5646 5647 /* 5648 * This table entry is not implemented. 5649 * 5650 * Inputs 5651 * (endpoint, asoc, chunk) 5652 * 5653 * The return value is the disposition of the chunk. 5654 */ 5655 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 5656 const struct sctp_association *asoc, 5657 const sctp_subtype_t type, 5658 void *arg, 5659 sctp_cmd_seq_t *commands) 5660 { 5661 return SCTP_DISPOSITION_NOT_IMPL; 5662 } 5663 5664 /* 5665 * This table entry represents a bug. 5666 * 5667 * Inputs 5668 * (endpoint, asoc, chunk) 5669 * 5670 * The return value is the disposition of the chunk. 5671 */ 5672 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 5673 const struct sctp_association *asoc, 5674 const sctp_subtype_t type, 5675 void *arg, 5676 sctp_cmd_seq_t *commands) 5677 { 5678 return SCTP_DISPOSITION_BUG; 5679 } 5680 5681 /* 5682 * This table entry represents the firing of a timer in the wrong state. 5683 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5684 * when the association is in the wrong state. This event should 5685 * be ignored, so as to prevent any rearming of the timer. 5686 * 5687 * Inputs 5688 * (endpoint, asoc, chunk) 5689 * 5690 * The return value is the disposition of the chunk. 5691 */ 5692 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 5693 const struct sctp_association *asoc, 5694 const sctp_subtype_t type, 5695 void *arg, 5696 sctp_cmd_seq_t *commands) 5697 { 5698 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5699 return SCTP_DISPOSITION_CONSUME; 5700 } 5701 5702 /******************************************************************** 5703 * 2nd Level Abstractions 5704 ********************************************************************/ 5705 5706 /* Pull the SACK chunk based on the SACK header. */ 5707 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5708 { 5709 struct sctp_sackhdr *sack; 5710 unsigned int len; 5711 __u16 num_blocks; 5712 __u16 num_dup_tsns; 5713 5714 /* Protect ourselves from reading too far into 5715 * the skb from a bogus sender. 5716 */ 5717 sack = (struct sctp_sackhdr *) chunk->skb->data; 5718 5719 num_blocks = ntohs(sack->num_gap_ack_blocks); 5720 num_dup_tsns = ntohs(sack->num_dup_tsns); 5721 len = sizeof(struct sctp_sackhdr); 5722 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5723 if (len > chunk->skb->len) 5724 return NULL; 5725 5726 skb_pull(chunk->skb, len); 5727 5728 return sack; 5729 } 5730 5731 /* Create an ABORT packet to be sent as a response, with the specified 5732 * error causes. 5733 */ 5734 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5735 const struct sctp_association *asoc, 5736 struct sctp_chunk *chunk, 5737 const void *payload, 5738 size_t paylen) 5739 { 5740 struct sctp_packet *packet; 5741 struct sctp_chunk *abort; 5742 5743 packet = sctp_ootb_pkt_new(asoc, chunk); 5744 5745 if (packet) { 5746 /* Make an ABORT. 5747 * The T bit will be set if the asoc is NULL. 5748 */ 5749 abort = sctp_make_abort(asoc, chunk, paylen); 5750 if (!abort) { 5751 sctp_ootb_pkt_free(packet); 5752 return NULL; 5753 } 5754 5755 /* Reflect vtag if T-Bit is set */ 5756 if (sctp_test_T_bit(abort)) 5757 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5758 5759 /* Add specified error causes, i.e., payload, to the 5760 * end of the chunk. 5761 */ 5762 sctp_addto_chunk(abort, paylen, payload); 5763 5764 /* Set the skb to the belonging sock for accounting. */ 5765 abort->skb->sk = ep->base.sk; 5766 5767 sctp_packet_append_chunk(packet, abort); 5768 5769 } 5770 5771 return packet; 5772 } 5773 5774 /* Allocate a packet for responding in the OOTB conditions. */ 5775 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5776 const struct sctp_chunk *chunk) 5777 { 5778 struct sctp_packet *packet; 5779 struct sctp_transport *transport; 5780 __u16 sport; 5781 __u16 dport; 5782 __u32 vtag; 5783 5784 /* Get the source and destination port from the inbound packet. */ 5785 sport = ntohs(chunk->sctp_hdr->dest); 5786 dport = ntohs(chunk->sctp_hdr->source); 5787 5788 /* The V-tag is going to be the same as the inbound packet if no 5789 * association exists, otherwise, use the peer's vtag. 5790 */ 5791 if (asoc) { 5792 /* Special case the INIT-ACK as there is no peer's vtag 5793 * yet. 5794 */ 5795 switch(chunk->chunk_hdr->type) { 5796 case SCTP_CID_INIT_ACK: 5797 { 5798 sctp_initack_chunk_t *initack; 5799 5800 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5801 vtag = ntohl(initack->init_hdr.init_tag); 5802 break; 5803 } 5804 default: 5805 vtag = asoc->peer.i.init_tag; 5806 break; 5807 } 5808 } else { 5809 /* Special case the INIT and stale COOKIE_ECHO as there is no 5810 * vtag yet. 5811 */ 5812 switch(chunk->chunk_hdr->type) { 5813 case SCTP_CID_INIT: 5814 { 5815 sctp_init_chunk_t *init; 5816 5817 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5818 vtag = ntohl(init->init_hdr.init_tag); 5819 break; 5820 } 5821 default: 5822 vtag = ntohl(chunk->sctp_hdr->vtag); 5823 break; 5824 } 5825 } 5826 5827 /* Make a transport for the bucket, Eliza... */ 5828 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5829 if (!transport) 5830 goto nomem; 5831 5832 /* Cache a route for the transport with the chunk's destination as 5833 * the source address. 5834 */ 5835 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5836 sctp_sk(sctp_get_ctl_sock())); 5837 5838 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5839 packet = sctp_packet_config(packet, vtag, 0); 5840 5841 return packet; 5842 5843 nomem: 5844 return NULL; 5845 } 5846 5847 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5848 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5849 { 5850 sctp_transport_free(packet->transport); 5851 } 5852 5853 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5854 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5855 const struct sctp_association *asoc, 5856 const struct sctp_chunk *chunk, 5857 sctp_cmd_seq_t *commands, 5858 struct sctp_chunk *err_chunk) 5859 { 5860 struct sctp_packet *packet; 5861 5862 if (err_chunk) { 5863 packet = sctp_ootb_pkt_new(asoc, chunk); 5864 if (packet) { 5865 struct sctp_signed_cookie *cookie; 5866 5867 /* Override the OOTB vtag from the cookie. */ 5868 cookie = chunk->subh.cookie_hdr; 5869 packet->vtag = cookie->c.peer_vtag; 5870 5871 /* Set the skb to the belonging sock for accounting. */ 5872 err_chunk->skb->sk = ep->base.sk; 5873 sctp_packet_append_chunk(packet, err_chunk); 5874 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5875 SCTP_PACKET(packet)); 5876 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5877 } else 5878 sctp_chunk_free (err_chunk); 5879 } 5880 } 5881 5882 5883 /* Process a data chunk */ 5884 static int sctp_eat_data(const struct sctp_association *asoc, 5885 struct sctp_chunk *chunk, 5886 sctp_cmd_seq_t *commands) 5887 { 5888 sctp_datahdr_t *data_hdr; 5889 struct sctp_chunk *err; 5890 size_t datalen; 5891 sctp_verb_t deliver; 5892 int tmp; 5893 __u32 tsn; 5894 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 5895 struct sock *sk = asoc->base.sk; 5896 u16 ssn; 5897 u16 sid; 5898 u8 ordered = 0; 5899 5900 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5901 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5902 5903 tsn = ntohl(data_hdr->tsn); 5904 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5905 5906 /* ASSERT: Now skb->data is really the user data. */ 5907 5908 /* Process ECN based congestion. 5909 * 5910 * Since the chunk structure is reused for all chunks within 5911 * a packet, we use ecn_ce_done to track if we've already 5912 * done CE processing for this packet. 5913 * 5914 * We need to do ECN processing even if we plan to discard the 5915 * chunk later. 5916 */ 5917 5918 if (!chunk->ecn_ce_done) { 5919 struct sctp_af *af; 5920 chunk->ecn_ce_done = 1; 5921 5922 af = sctp_get_af_specific( 5923 ipver2af(ip_hdr(chunk->skb)->version)); 5924 5925 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5926 /* Do real work as sideffect. */ 5927 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5928 SCTP_U32(tsn)); 5929 } 5930 } 5931 5932 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5933 if (tmp < 0) { 5934 /* The TSN is too high--silently discard the chunk and 5935 * count on it getting retransmitted later. 5936 */ 5937 return SCTP_IERROR_HIGH_TSN; 5938 } else if (tmp > 0) { 5939 /* This is a duplicate. Record it. */ 5940 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5941 return SCTP_IERROR_DUP_TSN; 5942 } 5943 5944 /* This is a new TSN. */ 5945 5946 /* Discard if there is no room in the receive window. 5947 * Actually, allow a little bit of overflow (up to a MTU). 5948 */ 5949 datalen = ntohs(chunk->chunk_hdr->length); 5950 datalen -= sizeof(sctp_data_chunk_t); 5951 5952 deliver = SCTP_CMD_CHUNK_ULP; 5953 5954 /* Think about partial delivery. */ 5955 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5956 5957 /* Even if we don't accept this chunk there is 5958 * memory pressure. 5959 */ 5960 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5961 } 5962 5963 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5964 * seems a bit troublesome in that frag_point varies based on 5965 * PMTU. In cases, such as loopback, this might be a rather 5966 * large spill over. 5967 */ 5968 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 5969 (datalen > asoc->rwnd + asoc->frag_point))) { 5970 5971 /* If this is the next TSN, consider reneging to make 5972 * room. Note: Playing nice with a confused sender. A 5973 * malicious sender can still eat up all our buffer 5974 * space and in the future we may want to detect and 5975 * do more drastic reneging. 5976 */ 5977 if (sctp_tsnmap_has_gap(map) && 5978 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5979 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5980 deliver = SCTP_CMD_RENEGE; 5981 } else { 5982 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5983 "rwnd: %d\n", tsn, datalen, 5984 asoc->rwnd); 5985 return SCTP_IERROR_IGNORE_TSN; 5986 } 5987 } 5988 5989 /* 5990 * Also try to renege to limit our memory usage in the event that 5991 * we are under memory pressure 5992 * If we can't renege, don't worry about it, the sk_rmem_schedule 5993 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 5994 * memory usage too much 5995 */ 5996 if (*sk->sk_prot_creator->memory_pressure) { 5997 if (sctp_tsnmap_has_gap(map) && 5998 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5999 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 6000 deliver = SCTP_CMD_RENEGE; 6001 } 6002 } 6003 6004 /* 6005 * Section 3.3.10.9 No User Data (9) 6006 * 6007 * Cause of error 6008 * --------------- 6009 * No User Data: This error cause is returned to the originator of a 6010 * DATA chunk if a received DATA chunk has no user data. 6011 */ 6012 if (unlikely(0 == datalen)) { 6013 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6014 if (err) { 6015 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6016 SCTP_CHUNK(err)); 6017 } 6018 /* We are going to ABORT, so we might as well stop 6019 * processing the rest of the chunks in the packet. 6020 */ 6021 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 6022 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6023 SCTP_ERROR(ECONNABORTED)); 6024 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6025 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6026 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 6027 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 6028 return SCTP_IERROR_NO_DATA; 6029 } 6030 6031 chunk->data_accepted = 1; 6032 6033 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6034 * if we renege and the chunk arrives again. 6035 */ 6036 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 6037 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 6038 else { 6039 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 6040 ordered = 1; 6041 } 6042 6043 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6044 * 6045 * If an endpoint receive a DATA chunk with an invalid stream 6046 * identifier, it shall acknowledge the reception of the DATA chunk 6047 * following the normal procedure, immediately send an ERROR chunk 6048 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6049 * and discard the DATA chunk. 6050 */ 6051 sid = ntohs(data_hdr->stream); 6052 if (sid >= asoc->c.sinit_max_instreams) { 6053 /* Mark tsn as received even though we drop it */ 6054 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6055 6056 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6057 &data_hdr->stream, 6058 sizeof(data_hdr->stream), 6059 sizeof(u16)); 6060 if (err) 6061 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6062 SCTP_CHUNK(err)); 6063 return SCTP_IERROR_BAD_STREAM; 6064 } 6065 6066 /* Check to see if the SSN is possible for this TSN. 6067 * The biggest gap we can record is 4K wide. Since SSNs wrap 6068 * at an unsigned short, there is no way that an SSN can 6069 * wrap and for a valid TSN. We can simply check if the current 6070 * SSN is smaller then the next expected one. If it is, it wrapped 6071 * and is invalid. 6072 */ 6073 ssn = ntohs(data_hdr->ssn); 6074 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6075 return SCTP_IERROR_PROTO_VIOLATION; 6076 } 6077 6078 /* Send the data up to the user. Note: Schedule the 6079 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6080 * chunk needs the updated rwnd. 6081 */ 6082 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6083 6084 return SCTP_IERROR_NO_ERROR; 6085 } 6086