1 /* SCTP kernel reference Implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This file is part of the SCTP kernel reference Implementation 9 * 10 * This is part of the SCTP Linux Kernel Reference Implementation. 11 * 12 * These are the state functions for the state machine. 13 * 14 * The SCTP reference implementation is free software; 15 * you can redistribute it and/or modify it under the terms of 16 * the GNU General Public License as published by 17 * the Free Software Foundation; either version 2, or (at your option) 18 * any later version. 19 * 20 * The SCTP reference implementation is distributed in the hope that it 21 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 22 * ************************ 23 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 24 * See the GNU General Public License for more details. 25 * 26 * You should have received a copy of the GNU General Public License 27 * along with GNU CC; see the file COPYING. If not, write to 28 * the Free Software Foundation, 59 Temple Place - Suite 330, 29 * Boston, MA 02111-1307, USA. 30 * 31 * Please send any bug reports or fixes you make to the 32 * email address(es): 33 * lksctp developers <lksctp-developers@lists.sourceforge.net> 34 * 35 * Or submit a bug report through the following website: 36 * http://www.sf.net/projects/lksctp 37 * 38 * Written or modified by: 39 * La Monte H.P. Yarroll <piggy@acm.org> 40 * Karl Knutson <karl@athena.chicago.il.us> 41 * Mathew Kotowsky <kotowsky@sctp.org> 42 * Sridhar Samudrala <samudrala@us.ibm.com> 43 * Jon Grimm <jgrimm@us.ibm.com> 44 * Hui Huang <hui.huang@nokia.com> 45 * Dajiang Zhang <dajiang.zhang@nokia.com> 46 * Daisy Chang <daisyc@us.ibm.com> 47 * Ardelle Fan <ardelle.fan@intel.com> 48 * Ryan Layer <rmlayer@us.ibm.com> 49 * Kevin Gao <kevin.gao@intel.com> 50 * 51 * Any bugs reported given to us we will try to fix... any fixes shared will 52 * be incorporated into the next SCTP release. 53 */ 54 55 #include <linux/types.h> 56 #include <linux/kernel.h> 57 #include <linux/ip.h> 58 #include <linux/ipv6.h> 59 #include <linux/net.h> 60 #include <linux/inet.h> 61 #include <net/sock.h> 62 #include <net/inet_ecn.h> 63 #include <linux/skbuff.h> 64 #include <net/sctp/sctp.h> 65 #include <net/sctp/sm.h> 66 #include <net/sctp/structs.h> 67 68 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 69 const struct sctp_association *asoc, 70 struct sctp_chunk *chunk, 71 const void *payload, 72 size_t paylen); 73 static int sctp_eat_data(const struct sctp_association *asoc, 74 struct sctp_chunk *chunk, 75 sctp_cmd_seq_t *commands); 76 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 77 const struct sctp_chunk *chunk); 78 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 79 const struct sctp_association *asoc, 80 const struct sctp_chunk *chunk, 81 sctp_cmd_seq_t *commands, 82 struct sctp_chunk *err_chunk); 83 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 84 const struct sctp_association *asoc, 85 const sctp_subtype_t type, 86 void *arg, 87 sctp_cmd_seq_t *commands); 88 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 89 const struct sctp_association *asoc, 90 const sctp_subtype_t type, 91 void *arg, 92 sctp_cmd_seq_t *commands); 93 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 94 95 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 96 __be16 error, int sk_err, 97 const struct sctp_association *asoc, 98 struct sctp_transport *transport); 99 100 static sctp_disposition_t sctp_sf_violation_chunklen( 101 const struct sctp_endpoint *ep, 102 const struct sctp_association *asoc, 103 const sctp_subtype_t type, 104 void *arg, 105 sctp_cmd_seq_t *commands); 106 107 /* Small helper function that checks if the chunk length 108 * is of the appropriate length. The 'required_length' argument 109 * is set to be the size of a specific chunk we are testing. 110 * Return Values: 1 = Valid length 111 * 0 = Invalid length 112 * 113 */ 114 static inline int 115 sctp_chunk_length_valid(struct sctp_chunk *chunk, 116 __u16 required_length) 117 { 118 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 119 120 if (unlikely(chunk_length < required_length)) 121 return 0; 122 123 return 1; 124 } 125 126 /********************************************************** 127 * These are the state functions for handling chunk events. 128 **********************************************************/ 129 130 /* 131 * Process the final SHUTDOWN COMPLETE. 132 * 133 * Section: 4 (C) (diagram), 9.2 134 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 135 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 136 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 137 * should stop the T2-shutdown timer and remove all knowledge of the 138 * association (and thus the association enters the CLOSED state). 139 * 140 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 141 * C) Rules for packet carrying SHUTDOWN COMPLETE: 142 * ... 143 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 144 * if the Verification Tag field of the packet matches its own tag and 145 * the T bit is not set 146 * OR 147 * it is set to its peer's tag and the T bit is set in the Chunk 148 * Flags. 149 * Otherwise, the receiver MUST silently discard the packet 150 * and take no further action. An endpoint MUST ignore the 151 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 152 * 153 * Inputs 154 * (endpoint, asoc, chunk) 155 * 156 * Outputs 157 * (asoc, reply_msg, msg_up, timers, counters) 158 * 159 * The return value is the disposition of the chunk. 160 */ 161 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, 162 const struct sctp_association *asoc, 163 const sctp_subtype_t type, 164 void *arg, 165 sctp_cmd_seq_t *commands) 166 { 167 struct sctp_chunk *chunk = arg; 168 struct sctp_ulpevent *ev; 169 170 /* RFC 2960 6.10 Bundling 171 * 172 * An endpoint MUST NOT bundle INIT, INIT ACK or 173 * SHUTDOWN COMPLETE with any other chunks. 174 */ 175 if (!chunk->singleton) 176 return SCTP_DISPOSITION_VIOLATION; 177 178 if (!sctp_vtag_verify_either(chunk, asoc)) 179 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 180 181 /* RFC 2960 10.2 SCTP-to-ULP 182 * 183 * H) SHUTDOWN COMPLETE notification 184 * 185 * When SCTP completes the shutdown procedures (section 9.2) this 186 * notification is passed to the upper layer. 187 */ 188 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 189 0, 0, 0, NULL, GFP_ATOMIC); 190 if (ev) 191 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 192 SCTP_ULPEVENT(ev)); 193 194 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 195 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 196 * not the chunk should be discarded. If the endpoint is in 197 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 198 * T2-shutdown timer and remove all knowledge of the 199 * association (and thus the association enters the CLOSED 200 * state). 201 */ 202 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 203 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 204 205 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 206 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 207 208 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 209 SCTP_STATE(SCTP_STATE_CLOSED)); 210 211 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 212 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 213 214 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 215 216 return SCTP_DISPOSITION_DELETE_TCB; 217 } 218 219 /* 220 * Respond to a normal INIT chunk. 221 * We are the side that is being asked for an association. 222 * 223 * Section: 5.1 Normal Establishment of an Association, B 224 * B) "Z" shall respond immediately with an INIT ACK chunk. The 225 * destination IP address of the INIT ACK MUST be set to the source 226 * IP address of the INIT to which this INIT ACK is responding. In 227 * the response, besides filling in other parameters, "Z" must set the 228 * Verification Tag field to Tag_A, and also provide its own 229 * Verification Tag (Tag_Z) in the Initiate Tag field. 230 * 231 * Verification Tag: Must be 0. 232 * 233 * Inputs 234 * (endpoint, asoc, chunk) 235 * 236 * Outputs 237 * (asoc, reply_msg, msg_up, timers, counters) 238 * 239 * The return value is the disposition of the chunk. 240 */ 241 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 242 const struct sctp_association *asoc, 243 const sctp_subtype_t type, 244 void *arg, 245 sctp_cmd_seq_t *commands) 246 { 247 struct sctp_chunk *chunk = arg; 248 struct sctp_chunk *repl; 249 struct sctp_association *new_asoc; 250 struct sctp_chunk *err_chunk; 251 struct sctp_packet *packet; 252 sctp_unrecognized_param_t *unk_param; 253 struct sock *sk; 254 int len; 255 256 /* 6.10 Bundling 257 * An endpoint MUST NOT bundle INIT, INIT ACK or 258 * SHUTDOWN COMPLETE with any other chunks. 259 * 260 * IG Section 2.11.2 261 * Furthermore, we require that the receiver of an INIT chunk MUST 262 * enforce these rules by silently discarding an arriving packet 263 * with an INIT chunk that is bundled with other chunks. 264 */ 265 if (!chunk->singleton) 266 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 267 268 /* If the packet is an OOTB packet which is temporarily on the 269 * control endpoint, respond with an ABORT. 270 */ 271 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 272 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 273 274 sk = ep->base.sk; 275 /* If the endpoint is not listening or if the number of associations 276 * on the TCP-style socket exceed the max backlog, respond with an 277 * ABORT. 278 */ 279 if (!sctp_sstate(sk, LISTENING) || 280 (sctp_style(sk, TCP) && 281 sk_acceptq_is_full(sk))) 282 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 283 284 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 285 * Tag. 286 */ 287 if (chunk->sctp_hdr->vtag != 0) 288 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 289 290 /* Make sure that the INIT chunk has a valid length. 291 * Normally, this would cause an ABORT with a Protocol Violation 292 * error, but since we don't have an association, we'll 293 * just discard the packet. 294 */ 295 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 296 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 297 298 /* Verify the INIT chunk before processing it. */ 299 err_chunk = NULL; 300 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 301 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 302 &err_chunk)) { 303 /* This chunk contains fatal error. It is to be discarded. 304 * Send an ABORT, with causes if there is any. 305 */ 306 if (err_chunk) { 307 packet = sctp_abort_pkt_new(ep, asoc, arg, 308 (__u8 *)(err_chunk->chunk_hdr) + 309 sizeof(sctp_chunkhdr_t), 310 ntohs(err_chunk->chunk_hdr->length) - 311 sizeof(sctp_chunkhdr_t)); 312 313 sctp_chunk_free(err_chunk); 314 315 if (packet) { 316 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 317 SCTP_PACKET(packet)); 318 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 319 return SCTP_DISPOSITION_CONSUME; 320 } else { 321 return SCTP_DISPOSITION_NOMEM; 322 } 323 } else { 324 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 325 commands); 326 } 327 } 328 329 /* Grab the INIT header. */ 330 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 331 332 /* Tag the variable length parameters. */ 333 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 334 335 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 336 if (!new_asoc) 337 goto nomem; 338 339 /* The call, sctp_process_init(), can fail on memory allocation. */ 340 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 341 sctp_source(chunk), 342 (sctp_init_chunk_t *)chunk->chunk_hdr, 343 GFP_ATOMIC)) 344 goto nomem_init; 345 346 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 347 348 /* If there are errors need to be reported for unknown parameters, 349 * make sure to reserve enough room in the INIT ACK for them. 350 */ 351 len = 0; 352 if (err_chunk) 353 len = ntohs(err_chunk->chunk_hdr->length) - 354 sizeof(sctp_chunkhdr_t); 355 356 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 357 goto nomem_init; 358 359 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 360 if (!repl) 361 goto nomem_init; 362 363 /* If there are errors need to be reported for unknown parameters, 364 * include them in the outgoing INIT ACK as "Unrecognized parameter" 365 * parameter. 366 */ 367 if (err_chunk) { 368 /* Get the "Unrecognized parameter" parameter(s) out of the 369 * ERROR chunk generated by sctp_verify_init(). Since the 370 * error cause code for "unknown parameter" and the 371 * "Unrecognized parameter" type is the same, we can 372 * construct the parameters in INIT ACK by copying the 373 * ERROR causes over. 374 */ 375 unk_param = (sctp_unrecognized_param_t *) 376 ((__u8 *)(err_chunk->chunk_hdr) + 377 sizeof(sctp_chunkhdr_t)); 378 /* Replace the cause code with the "Unrecognized parameter" 379 * parameter type. 380 */ 381 sctp_addto_chunk(repl, len, unk_param); 382 sctp_chunk_free(err_chunk); 383 } 384 385 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 386 387 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 388 389 /* 390 * Note: After sending out INIT ACK with the State Cookie parameter, 391 * "Z" MUST NOT allocate any resources, nor keep any states for the 392 * new association. Otherwise, "Z" will be vulnerable to resource 393 * attacks. 394 */ 395 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 396 397 return SCTP_DISPOSITION_DELETE_TCB; 398 399 nomem_init: 400 sctp_association_free(new_asoc); 401 nomem: 402 if (err_chunk) 403 sctp_chunk_free(err_chunk); 404 return SCTP_DISPOSITION_NOMEM; 405 } 406 407 /* 408 * Respond to a normal INIT ACK chunk. 409 * We are the side that is initiating the association. 410 * 411 * Section: 5.1 Normal Establishment of an Association, C 412 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 413 * timer and leave COOKIE-WAIT state. "A" shall then send the State 414 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 415 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 416 * 417 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 418 * DATA chunks, but it MUST be the first chunk in the packet and 419 * until the COOKIE ACK is returned the sender MUST NOT send any 420 * other packets to the peer. 421 * 422 * Verification Tag: 3.3.3 423 * If the value of the Initiate Tag in a received INIT ACK chunk is 424 * found to be 0, the receiver MUST treat it as an error and close the 425 * association by transmitting an ABORT. 426 * 427 * Inputs 428 * (endpoint, asoc, chunk) 429 * 430 * Outputs 431 * (asoc, reply_msg, msg_up, timers, counters) 432 * 433 * The return value is the disposition of the chunk. 434 */ 435 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, 436 const struct sctp_association *asoc, 437 const sctp_subtype_t type, 438 void *arg, 439 sctp_cmd_seq_t *commands) 440 { 441 struct sctp_chunk *chunk = arg; 442 sctp_init_chunk_t *initchunk; 443 struct sctp_chunk *err_chunk; 444 struct sctp_packet *packet; 445 sctp_error_t error; 446 447 if (!sctp_vtag_verify(chunk, asoc)) 448 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 449 450 /* Make sure that the INIT-ACK chunk has a valid length */ 451 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 452 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 453 commands); 454 /* 6.10 Bundling 455 * An endpoint MUST NOT bundle INIT, INIT ACK or 456 * SHUTDOWN COMPLETE with any other chunks. 457 */ 458 if (!chunk->singleton) 459 return SCTP_DISPOSITION_VIOLATION; 460 461 /* Grab the INIT header. */ 462 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 463 464 /* Verify the INIT chunk before processing it. */ 465 err_chunk = NULL; 466 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 467 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 468 &err_chunk)) { 469 470 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 471 472 /* This chunk contains fatal error. It is to be discarded. 473 * Send an ABORT, with causes if there is any. 474 */ 475 if (err_chunk) { 476 packet = sctp_abort_pkt_new(ep, asoc, arg, 477 (__u8 *)(err_chunk->chunk_hdr) + 478 sizeof(sctp_chunkhdr_t), 479 ntohs(err_chunk->chunk_hdr->length) - 480 sizeof(sctp_chunkhdr_t)); 481 482 sctp_chunk_free(err_chunk); 483 484 if (packet) { 485 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 486 SCTP_PACKET(packet)); 487 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 488 error = SCTP_ERROR_INV_PARAM; 489 } else { 490 error = SCTP_ERROR_NO_RESOURCE; 491 } 492 } else { 493 sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 494 error = SCTP_ERROR_INV_PARAM; 495 } 496 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, 497 asoc, chunk->transport); 498 } 499 500 /* Tag the variable length parameters. Note that we never 501 * convert the parameters in an INIT chunk. 502 */ 503 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 504 505 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 506 507 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 508 SCTP_PEER_INIT(initchunk)); 509 510 /* Reset init error count upon receipt of INIT-ACK. */ 511 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 512 513 /* 5.1 C) "A" shall stop the T1-init timer and leave 514 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 515 * timer, and enter the COOKIE-ECHOED state. 516 */ 517 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 518 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 519 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 520 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 521 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 522 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 523 524 /* 5.1 C) "A" shall then send the State Cookie received in the 525 * INIT ACK chunk in a COOKIE ECHO chunk, ... 526 */ 527 /* If there is any errors to report, send the ERROR chunk generated 528 * for unknown parameters as well. 529 */ 530 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 531 SCTP_CHUNK(err_chunk)); 532 533 return SCTP_DISPOSITION_CONSUME; 534 } 535 536 /* 537 * Respond to a normal COOKIE ECHO chunk. 538 * We are the side that is being asked for an association. 539 * 540 * Section: 5.1 Normal Establishment of an Association, D 541 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 542 * with a COOKIE ACK chunk after building a TCB and moving to 543 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 544 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 545 * chunk MUST be the first chunk in the packet. 546 * 547 * IMPLEMENTATION NOTE: An implementation may choose to send the 548 * Communication Up notification to the SCTP user upon reception 549 * of a valid COOKIE ECHO chunk. 550 * 551 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 552 * D) Rules for packet carrying a COOKIE ECHO 553 * 554 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 555 * Initial Tag received in the INIT ACK. 556 * 557 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 558 * 559 * Inputs 560 * (endpoint, asoc, chunk) 561 * 562 * Outputs 563 * (asoc, reply_msg, msg_up, timers, counters) 564 * 565 * The return value is the disposition of the chunk. 566 */ 567 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, 568 const struct sctp_association *asoc, 569 const sctp_subtype_t type, void *arg, 570 sctp_cmd_seq_t *commands) 571 { 572 struct sctp_chunk *chunk = arg; 573 struct sctp_association *new_asoc; 574 sctp_init_chunk_t *peer_init; 575 struct sctp_chunk *repl; 576 struct sctp_ulpevent *ev, *ai_ev = NULL; 577 int error = 0; 578 struct sctp_chunk *err_chk_p; 579 580 /* If the packet is an OOTB packet which is temporarily on the 581 * control endpoint, respond with an ABORT. 582 */ 583 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 584 return sctp_sf_ootb(ep, asoc, type, arg, commands); 585 586 /* Make sure that the COOKIE_ECHO chunk has a valid length. 587 * In this case, we check that we have enough for at least a 588 * chunk header. More detailed verification is done 589 * in sctp_unpack_cookie(). 590 */ 591 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 592 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 593 594 /* "Decode" the chunk. We have no optional parameters so we 595 * are in good shape. 596 */ 597 chunk->subh.cookie_hdr = 598 (struct sctp_signed_cookie *)chunk->skb->data; 599 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 600 sizeof(sctp_chunkhdr_t))) 601 goto nomem; 602 603 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 604 * "Z" will reply with a COOKIE ACK chunk after building a TCB 605 * and moving to the ESTABLISHED state. 606 */ 607 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 608 &err_chk_p); 609 610 /* FIXME: 611 * If the re-build failed, what is the proper error path 612 * from here? 613 * 614 * [We should abort the association. --piggy] 615 */ 616 if (!new_asoc) { 617 /* FIXME: Several errors are possible. A bad cookie should 618 * be silently discarded, but think about logging it too. 619 */ 620 switch (error) { 621 case -SCTP_IERROR_NOMEM: 622 goto nomem; 623 624 case -SCTP_IERROR_STALE_COOKIE: 625 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 626 err_chk_p); 627 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 628 629 case -SCTP_IERROR_BAD_SIG: 630 default: 631 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 632 } 633 } 634 635 636 /* Delay state machine commands until later. 637 * 638 * Re-build the bind address for the association is done in 639 * the sctp_unpack_cookie() already. 640 */ 641 /* This is a brand-new association, so these are not yet side 642 * effects--it is safe to run them here. 643 */ 644 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 645 646 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 647 &chunk->subh.cookie_hdr->c.peer_addr, 648 peer_init, GFP_ATOMIC)) 649 goto nomem_init; 650 651 repl = sctp_make_cookie_ack(new_asoc, chunk); 652 if (!repl) 653 goto nomem_init; 654 655 /* RFC 2960 5.1 Normal Establishment of an Association 656 * 657 * D) IMPLEMENTATION NOTE: An implementation may choose to 658 * send the Communication Up notification to the SCTP user 659 * upon reception of a valid COOKIE ECHO chunk. 660 */ 661 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 662 new_asoc->c.sinit_num_ostreams, 663 new_asoc->c.sinit_max_instreams, 664 NULL, GFP_ATOMIC); 665 if (!ev) 666 goto nomem_ev; 667 668 /* Sockets API Draft Section 5.3.1.6 669 * When a peer sends a Adaptation Layer Indication parameter , SCTP 670 * delivers this notification to inform the application that of the 671 * peers requested adaptation layer. 672 */ 673 if (new_asoc->peer.adaptation_ind) { 674 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 675 GFP_ATOMIC); 676 if (!ai_ev) 677 goto nomem_aiev; 678 } 679 680 /* Add all the state machine commands now since we've created 681 * everything. This way we don't introduce memory corruptions 682 * during side-effect processing and correclty count established 683 * associations. 684 */ 685 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 686 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 687 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 688 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 689 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 690 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 691 692 if (new_asoc->autoclose) 693 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 694 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 695 696 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 697 698 /* This will send the COOKIE ACK */ 699 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 700 701 /* Queue the ASSOC_CHANGE event */ 702 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 703 704 /* Send up the Adaptation Layer Indication event */ 705 if (ai_ev) 706 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 707 SCTP_ULPEVENT(ai_ev)); 708 709 return SCTP_DISPOSITION_CONSUME; 710 711 nomem_aiev: 712 sctp_ulpevent_free(ev); 713 nomem_ev: 714 sctp_chunk_free(repl); 715 nomem_init: 716 sctp_association_free(new_asoc); 717 nomem: 718 return SCTP_DISPOSITION_NOMEM; 719 } 720 721 /* 722 * Respond to a normal COOKIE ACK chunk. 723 * We are the side that is being asked for an association. 724 * 725 * RFC 2960 5.1 Normal Establishment of an Association 726 * 727 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 728 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 729 * timer. It may also notify its ULP about the successful 730 * establishment of the association with a Communication Up 731 * notification (see Section 10). 732 * 733 * Verification Tag: 734 * Inputs 735 * (endpoint, asoc, chunk) 736 * 737 * Outputs 738 * (asoc, reply_msg, msg_up, timers, counters) 739 * 740 * The return value is the disposition of the chunk. 741 */ 742 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, 743 const struct sctp_association *asoc, 744 const sctp_subtype_t type, void *arg, 745 sctp_cmd_seq_t *commands) 746 { 747 struct sctp_chunk *chunk = arg; 748 struct sctp_ulpevent *ev; 749 750 if (!sctp_vtag_verify(chunk, asoc)) 751 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 752 753 /* Verify that the chunk length for the COOKIE-ACK is OK. 754 * If we don't do this, any bundled chunks may be junked. 755 */ 756 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 757 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 758 commands); 759 760 /* Reset init error count upon receipt of COOKIE-ACK, 761 * to avoid problems with the managemement of this 762 * counter in stale cookie situations when a transition back 763 * from the COOKIE-ECHOED state to the COOKIE-WAIT 764 * state is performed. 765 */ 766 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 767 768 /* RFC 2960 5.1 Normal Establishment of an Association 769 * 770 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 771 * from the COOKIE-ECHOED state to the ESTABLISHED state, 772 * stopping the T1-cookie timer. 773 */ 774 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 775 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 776 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 777 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 778 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 779 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); 780 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 781 if (asoc->autoclose) 782 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 783 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 784 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 785 786 /* It may also notify its ULP about the successful 787 * establishment of the association with a Communication Up 788 * notification (see Section 10). 789 */ 790 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 791 0, asoc->c.sinit_num_ostreams, 792 asoc->c.sinit_max_instreams, 793 NULL, GFP_ATOMIC); 794 795 if (!ev) 796 goto nomem; 797 798 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 799 800 /* Sockets API Draft Section 5.3.1.6 801 * When a peer sends a Adaptation Layer Indication parameter , SCTP 802 * delivers this notification to inform the application that of the 803 * peers requested adaptation layer. 804 */ 805 if (asoc->peer.adaptation_ind) { 806 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 807 if (!ev) 808 goto nomem; 809 810 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 811 SCTP_ULPEVENT(ev)); 812 } 813 814 return SCTP_DISPOSITION_CONSUME; 815 nomem: 816 return SCTP_DISPOSITION_NOMEM; 817 } 818 819 /* Generate and sendout a heartbeat packet. */ 820 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 821 const struct sctp_association *asoc, 822 const sctp_subtype_t type, 823 void *arg, 824 sctp_cmd_seq_t *commands) 825 { 826 struct sctp_transport *transport = (struct sctp_transport *) arg; 827 struct sctp_chunk *reply; 828 sctp_sender_hb_info_t hbinfo; 829 size_t paylen = 0; 830 831 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; 832 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); 833 hbinfo.daddr = transport->ipaddr; 834 hbinfo.sent_at = jiffies; 835 hbinfo.hb_nonce = transport->hb_nonce; 836 837 /* Send a heartbeat to our peer. */ 838 paylen = sizeof(sctp_sender_hb_info_t); 839 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); 840 if (!reply) 841 return SCTP_DISPOSITION_NOMEM; 842 843 /* Set rto_pending indicating that an RTT measurement 844 * is started with this heartbeat chunk. 845 */ 846 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 847 SCTP_TRANSPORT(transport)); 848 849 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 850 return SCTP_DISPOSITION_CONSUME; 851 } 852 853 /* Generate a HEARTBEAT packet on the given transport. */ 854 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 855 const struct sctp_association *asoc, 856 const sctp_subtype_t type, 857 void *arg, 858 sctp_cmd_seq_t *commands) 859 { 860 struct sctp_transport *transport = (struct sctp_transport *) arg; 861 862 if (asoc->overall_error_count >= asoc->max_retrans) { 863 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 864 SCTP_ERROR(ETIMEDOUT)); 865 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 866 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 867 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 868 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 869 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 870 return SCTP_DISPOSITION_DELETE_TCB; 871 } 872 873 /* Section 3.3.5. 874 * The Sender-specific Heartbeat Info field should normally include 875 * information about the sender's current time when this HEARTBEAT 876 * chunk is sent and the destination transport address to which this 877 * HEARTBEAT is sent (see Section 8.3). 878 */ 879 880 if (transport->param_flags & SPP_HB_ENABLE) { 881 if (SCTP_DISPOSITION_NOMEM == 882 sctp_sf_heartbeat(ep, asoc, type, arg, 883 commands)) 884 return SCTP_DISPOSITION_NOMEM; 885 /* Set transport error counter and association error counter 886 * when sending heartbeat. 887 */ 888 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 889 SCTP_TRANSPORT(transport)); 890 } 891 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 892 SCTP_TRANSPORT(transport)); 893 894 return SCTP_DISPOSITION_CONSUME; 895 } 896 897 /* 898 * Process an heartbeat request. 899 * 900 * Section: 8.3 Path Heartbeat 901 * The receiver of the HEARTBEAT should immediately respond with a 902 * HEARTBEAT ACK that contains the Heartbeat Information field copied 903 * from the received HEARTBEAT chunk. 904 * 905 * Verification Tag: 8.5 Verification Tag [Normal verification] 906 * When receiving an SCTP packet, the endpoint MUST ensure that the 907 * value in the Verification Tag field of the received SCTP packet 908 * matches its own Tag. If the received Verification Tag value does not 909 * match the receiver's own tag value, the receiver shall silently 910 * discard the packet and shall not process it any further except for 911 * those cases listed in Section 8.5.1 below. 912 * 913 * Inputs 914 * (endpoint, asoc, chunk) 915 * 916 * Outputs 917 * (asoc, reply_msg, msg_up, timers, counters) 918 * 919 * The return value is the disposition of the chunk. 920 */ 921 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 922 const struct sctp_association *asoc, 923 const sctp_subtype_t type, 924 void *arg, 925 sctp_cmd_seq_t *commands) 926 { 927 struct sctp_chunk *chunk = arg; 928 struct sctp_chunk *reply; 929 size_t paylen = 0; 930 931 if (!sctp_vtag_verify(chunk, asoc)) 932 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 933 934 /* Make sure that the HEARTBEAT chunk has a valid length. */ 935 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 936 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 937 commands); 938 939 /* 8.3 The receiver of the HEARTBEAT should immediately 940 * respond with a HEARTBEAT ACK that contains the Heartbeat 941 * Information field copied from the received HEARTBEAT chunk. 942 */ 943 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 944 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 945 if (!pskb_pull(chunk->skb, paylen)) 946 goto nomem; 947 948 reply = sctp_make_heartbeat_ack(asoc, chunk, 949 chunk->subh.hb_hdr, paylen); 950 if (!reply) 951 goto nomem; 952 953 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 954 return SCTP_DISPOSITION_CONSUME; 955 956 nomem: 957 return SCTP_DISPOSITION_NOMEM; 958 } 959 960 /* 961 * Process the returning HEARTBEAT ACK. 962 * 963 * Section: 8.3 Path Heartbeat 964 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 965 * should clear the error counter of the destination transport 966 * address to which the HEARTBEAT was sent, and mark the destination 967 * transport address as active if it is not so marked. The endpoint may 968 * optionally report to the upper layer when an inactive destination 969 * address is marked as active due to the reception of the latest 970 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 971 * clear the association overall error count as well (as defined 972 * in section 8.1). 973 * 974 * The receiver of the HEARTBEAT ACK should also perform an RTT 975 * measurement for that destination transport address using the time 976 * value carried in the HEARTBEAT ACK chunk. 977 * 978 * Verification Tag: 8.5 Verification Tag [Normal verification] 979 * 980 * Inputs 981 * (endpoint, asoc, chunk) 982 * 983 * Outputs 984 * (asoc, reply_msg, msg_up, timers, counters) 985 * 986 * The return value is the disposition of the chunk. 987 */ 988 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 989 const struct sctp_association *asoc, 990 const sctp_subtype_t type, 991 void *arg, 992 sctp_cmd_seq_t *commands) 993 { 994 struct sctp_chunk *chunk = arg; 995 union sctp_addr from_addr; 996 struct sctp_transport *link; 997 sctp_sender_hb_info_t *hbinfo; 998 unsigned long max_interval; 999 1000 if (!sctp_vtag_verify(chunk, asoc)) 1001 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1002 1003 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1004 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1005 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1006 commands); 1007 1008 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1009 /* Make sure that the length of the parameter is what we expect */ 1010 if (ntohs(hbinfo->param_hdr.length) != 1011 sizeof(sctp_sender_hb_info_t)) { 1012 return SCTP_DISPOSITION_DISCARD; 1013 } 1014 1015 from_addr = hbinfo->daddr; 1016 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1017 1018 /* This should never happen, but lets log it if so. */ 1019 if (unlikely(!link)) { 1020 if (from_addr.sa.sa_family == AF_INET6) { 1021 printk(KERN_WARNING 1022 "%s association %p could not find address " 1023 NIP6_FMT "\n", 1024 __FUNCTION__, 1025 asoc, 1026 NIP6(from_addr.v6.sin6_addr)); 1027 } else { 1028 printk(KERN_WARNING 1029 "%s association %p could not find address " 1030 NIPQUAD_FMT "\n", 1031 __FUNCTION__, 1032 asoc, 1033 NIPQUAD(from_addr.v4.sin_addr.s_addr)); 1034 } 1035 return SCTP_DISPOSITION_DISCARD; 1036 } 1037 1038 /* Validate the 64-bit random nonce. */ 1039 if (hbinfo->hb_nonce != link->hb_nonce) 1040 return SCTP_DISPOSITION_DISCARD; 1041 1042 max_interval = link->hbinterval + link->rto; 1043 1044 /* Check if the timestamp looks valid. */ 1045 if (time_after(hbinfo->sent_at, jiffies) || 1046 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1047 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp" 1048 "received for transport: %p\n", 1049 __FUNCTION__, link); 1050 return SCTP_DISPOSITION_DISCARD; 1051 } 1052 1053 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1054 * the HEARTBEAT should clear the error counter of the 1055 * destination transport address to which the HEARTBEAT was 1056 * sent and mark the destination transport address as active if 1057 * it is not so marked. 1058 */ 1059 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1060 1061 return SCTP_DISPOSITION_CONSUME; 1062 } 1063 1064 /* Helper function to send out an abort for the restart 1065 * condition. 1066 */ 1067 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1068 struct sctp_chunk *init, 1069 sctp_cmd_seq_t *commands) 1070 { 1071 int len; 1072 struct sctp_packet *pkt; 1073 union sctp_addr_param *addrparm; 1074 struct sctp_errhdr *errhdr; 1075 struct sctp_endpoint *ep; 1076 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1077 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1078 1079 /* Build the error on the stack. We are way to malloc crazy 1080 * throughout the code today. 1081 */ 1082 errhdr = (struct sctp_errhdr *)buffer; 1083 addrparm = (union sctp_addr_param *)errhdr->variable; 1084 1085 /* Copy into a parm format. */ 1086 len = af->to_addr_param(ssa, addrparm); 1087 len += sizeof(sctp_errhdr_t); 1088 1089 errhdr->cause = SCTP_ERROR_RESTART; 1090 errhdr->length = htons(len); 1091 1092 /* Assign to the control socket. */ 1093 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1094 1095 /* Association is NULL since this may be a restart attack and we 1096 * want to send back the attacker's vtag. 1097 */ 1098 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1099 1100 if (!pkt) 1101 goto out; 1102 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1103 1104 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1105 1106 /* Discard the rest of the inbound packet. */ 1107 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1108 1109 out: 1110 /* Even if there is no memory, treat as a failure so 1111 * the packet will get dropped. 1112 */ 1113 return 0; 1114 } 1115 1116 /* A restart is occurring, check to make sure no new addresses 1117 * are being added as we may be under a takeover attack. 1118 */ 1119 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1120 const struct sctp_association *asoc, 1121 struct sctp_chunk *init, 1122 sctp_cmd_seq_t *commands) 1123 { 1124 struct sctp_transport *new_addr, *addr; 1125 struct list_head *pos, *pos2; 1126 int found; 1127 1128 /* Implementor's Guide - Sectin 5.2.2 1129 * ... 1130 * Before responding the endpoint MUST check to see if the 1131 * unexpected INIT adds new addresses to the association. If new 1132 * addresses are added to the association, the endpoint MUST respond 1133 * with an ABORT.. 1134 */ 1135 1136 /* Search through all current addresses and make sure 1137 * we aren't adding any new ones. 1138 */ 1139 new_addr = NULL; 1140 found = 0; 1141 1142 list_for_each(pos, &new_asoc->peer.transport_addr_list) { 1143 new_addr = list_entry(pos, struct sctp_transport, transports); 1144 found = 0; 1145 list_for_each(pos2, &asoc->peer.transport_addr_list) { 1146 addr = list_entry(pos2, struct sctp_transport, 1147 transports); 1148 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1149 &addr->ipaddr)) { 1150 found = 1; 1151 break; 1152 } 1153 } 1154 if (!found) 1155 break; 1156 } 1157 1158 /* If a new address was added, ABORT the sender. */ 1159 if (!found && new_addr) { 1160 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1161 } 1162 1163 /* Return success if all addresses were found. */ 1164 return found; 1165 } 1166 1167 /* Populate the verification/tie tags based on overlapping INIT 1168 * scenario. 1169 * 1170 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1171 */ 1172 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1173 const struct sctp_association *asoc) 1174 { 1175 switch (asoc->state) { 1176 1177 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1178 1179 case SCTP_STATE_COOKIE_WAIT: 1180 new_asoc->c.my_vtag = asoc->c.my_vtag; 1181 new_asoc->c.my_ttag = asoc->c.my_vtag; 1182 new_asoc->c.peer_ttag = 0; 1183 break; 1184 1185 case SCTP_STATE_COOKIE_ECHOED: 1186 new_asoc->c.my_vtag = asoc->c.my_vtag; 1187 new_asoc->c.my_ttag = asoc->c.my_vtag; 1188 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1189 break; 1190 1191 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1192 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1193 */ 1194 default: 1195 new_asoc->c.my_ttag = asoc->c.my_vtag; 1196 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1197 break; 1198 } 1199 1200 /* Other parameters for the endpoint SHOULD be copied from the 1201 * existing parameters of the association (e.g. number of 1202 * outbound streams) into the INIT ACK and cookie. 1203 */ 1204 new_asoc->rwnd = asoc->rwnd; 1205 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1206 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1207 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1208 } 1209 1210 /* 1211 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1212 * handling action. 1213 * 1214 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1215 * 1216 * Returns value representing action to be taken. These action values 1217 * correspond to Action/Description values in RFC 2960, Table 2. 1218 */ 1219 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1220 const struct sctp_association *asoc) 1221 { 1222 /* In this case, the peer may have restarted. */ 1223 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1224 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1225 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1226 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1227 return 'A'; 1228 1229 /* Collision case B. */ 1230 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1231 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1232 (0 == asoc->c.peer_vtag))) { 1233 return 'B'; 1234 } 1235 1236 /* Collision case D. */ 1237 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1238 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1239 return 'D'; 1240 1241 /* Collision case C. */ 1242 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1243 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1244 (0 == new_asoc->c.my_ttag) && 1245 (0 == new_asoc->c.peer_ttag)) 1246 return 'C'; 1247 1248 /* No match to any of the special cases; discard this packet. */ 1249 return 'E'; 1250 } 1251 1252 /* Common helper routine for both duplicate and simulataneous INIT 1253 * chunk handling. 1254 */ 1255 static sctp_disposition_t sctp_sf_do_unexpected_init( 1256 const struct sctp_endpoint *ep, 1257 const struct sctp_association *asoc, 1258 const sctp_subtype_t type, 1259 void *arg, sctp_cmd_seq_t *commands) 1260 { 1261 sctp_disposition_t retval; 1262 struct sctp_chunk *chunk = arg; 1263 struct sctp_chunk *repl; 1264 struct sctp_association *new_asoc; 1265 struct sctp_chunk *err_chunk; 1266 struct sctp_packet *packet; 1267 sctp_unrecognized_param_t *unk_param; 1268 int len; 1269 1270 /* 6.10 Bundling 1271 * An endpoint MUST NOT bundle INIT, INIT ACK or 1272 * SHUTDOWN COMPLETE with any other chunks. 1273 * 1274 * IG Section 2.11.2 1275 * Furthermore, we require that the receiver of an INIT chunk MUST 1276 * enforce these rules by silently discarding an arriving packet 1277 * with an INIT chunk that is bundled with other chunks. 1278 */ 1279 if (!chunk->singleton) 1280 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1281 1282 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1283 * Tag. 1284 */ 1285 if (chunk->sctp_hdr->vtag != 0) 1286 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1287 1288 /* Make sure that the INIT chunk has a valid length. 1289 * In this case, we generate a protocol violation since we have 1290 * an association established. 1291 */ 1292 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1293 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1294 commands); 1295 /* Grab the INIT header. */ 1296 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1297 1298 /* Tag the variable length parameters. */ 1299 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1300 1301 /* Verify the INIT chunk before processing it. */ 1302 err_chunk = NULL; 1303 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1304 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1305 &err_chunk)) { 1306 /* This chunk contains fatal error. It is to be discarded. 1307 * Send an ABORT, with causes if there is any. 1308 */ 1309 if (err_chunk) { 1310 packet = sctp_abort_pkt_new(ep, asoc, arg, 1311 (__u8 *)(err_chunk->chunk_hdr) + 1312 sizeof(sctp_chunkhdr_t), 1313 ntohs(err_chunk->chunk_hdr->length) - 1314 sizeof(sctp_chunkhdr_t)); 1315 1316 if (packet) { 1317 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1318 SCTP_PACKET(packet)); 1319 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1320 retval = SCTP_DISPOSITION_CONSUME; 1321 } else { 1322 retval = SCTP_DISPOSITION_NOMEM; 1323 } 1324 goto cleanup; 1325 } else { 1326 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1327 commands); 1328 } 1329 } 1330 1331 /* 1332 * Other parameters for the endpoint SHOULD be copied from the 1333 * existing parameters of the association (e.g. number of 1334 * outbound streams) into the INIT ACK and cookie. 1335 * FIXME: We are copying parameters from the endpoint not the 1336 * association. 1337 */ 1338 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1339 if (!new_asoc) 1340 goto nomem; 1341 1342 /* In the outbound INIT ACK the endpoint MUST copy its current 1343 * Verification Tag and Peers Verification tag into a reserved 1344 * place (local tie-tag and per tie-tag) within the state cookie. 1345 */ 1346 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1347 sctp_source(chunk), 1348 (sctp_init_chunk_t *)chunk->chunk_hdr, 1349 GFP_ATOMIC)) 1350 goto nomem; 1351 1352 /* Make sure no new addresses are being added during the 1353 * restart. Do not do this check for COOKIE-WAIT state, 1354 * since there are no peer addresses to check against. 1355 * Upon return an ABORT will have been sent if needed. 1356 */ 1357 if (!sctp_state(asoc, COOKIE_WAIT)) { 1358 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1359 commands)) { 1360 retval = SCTP_DISPOSITION_CONSUME; 1361 goto nomem_retval; 1362 } 1363 } 1364 1365 sctp_tietags_populate(new_asoc, asoc); 1366 1367 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1368 1369 /* If there are errors need to be reported for unknown parameters, 1370 * make sure to reserve enough room in the INIT ACK for them. 1371 */ 1372 len = 0; 1373 if (err_chunk) { 1374 len = ntohs(err_chunk->chunk_hdr->length) - 1375 sizeof(sctp_chunkhdr_t); 1376 } 1377 1378 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 1379 goto nomem; 1380 1381 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1382 if (!repl) 1383 goto nomem; 1384 1385 /* If there are errors need to be reported for unknown parameters, 1386 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1387 * parameter. 1388 */ 1389 if (err_chunk) { 1390 /* Get the "Unrecognized parameter" parameter(s) out of the 1391 * ERROR chunk generated by sctp_verify_init(). Since the 1392 * error cause code for "unknown parameter" and the 1393 * "Unrecognized parameter" type is the same, we can 1394 * construct the parameters in INIT ACK by copying the 1395 * ERROR causes over. 1396 */ 1397 unk_param = (sctp_unrecognized_param_t *) 1398 ((__u8 *)(err_chunk->chunk_hdr) + 1399 sizeof(sctp_chunkhdr_t)); 1400 /* Replace the cause code with the "Unrecognized parameter" 1401 * parameter type. 1402 */ 1403 sctp_addto_chunk(repl, len, unk_param); 1404 } 1405 1406 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1407 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1408 1409 /* 1410 * Note: After sending out INIT ACK with the State Cookie parameter, 1411 * "Z" MUST NOT allocate any resources for this new association. 1412 * Otherwise, "Z" will be vulnerable to resource attacks. 1413 */ 1414 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1415 retval = SCTP_DISPOSITION_CONSUME; 1416 1417 return retval; 1418 1419 nomem: 1420 retval = SCTP_DISPOSITION_NOMEM; 1421 nomem_retval: 1422 if (new_asoc) 1423 sctp_association_free(new_asoc); 1424 cleanup: 1425 if (err_chunk) 1426 sctp_chunk_free(err_chunk); 1427 return retval; 1428 } 1429 1430 /* 1431 * Handle simultanous INIT. 1432 * This means we started an INIT and then we got an INIT request from 1433 * our peer. 1434 * 1435 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1436 * This usually indicates an initialization collision, i.e., each 1437 * endpoint is attempting, at about the same time, to establish an 1438 * association with the other endpoint. 1439 * 1440 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1441 * endpoint MUST respond with an INIT ACK using the same parameters it 1442 * sent in its original INIT chunk (including its Verification Tag, 1443 * unchanged). These original parameters are combined with those from the 1444 * newly received INIT chunk. The endpoint shall also generate a State 1445 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1446 * INIT to calculate the State Cookie. 1447 * 1448 * After that, the endpoint MUST NOT change its state, the T1-init 1449 * timer shall be left running and the corresponding TCB MUST NOT be 1450 * destroyed. The normal procedures for handling State Cookies when 1451 * a TCB exists will resolve the duplicate INITs to a single association. 1452 * 1453 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1454 * its Tie-Tags with the Tag information of itself and its peer (see 1455 * section 5.2.2 for a description of the Tie-Tags). 1456 * 1457 * Verification Tag: Not explicit, but an INIT can not have a valid 1458 * verification tag, so we skip the check. 1459 * 1460 * Inputs 1461 * (endpoint, asoc, chunk) 1462 * 1463 * Outputs 1464 * (asoc, reply_msg, msg_up, timers, counters) 1465 * 1466 * The return value is the disposition of the chunk. 1467 */ 1468 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1469 const struct sctp_association *asoc, 1470 const sctp_subtype_t type, 1471 void *arg, 1472 sctp_cmd_seq_t *commands) 1473 { 1474 /* Call helper to do the real work for both simulataneous and 1475 * duplicate INIT chunk handling. 1476 */ 1477 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1478 } 1479 1480 /* 1481 * Handle duplicated INIT messages. These are usually delayed 1482 * restransmissions. 1483 * 1484 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1485 * COOKIE-ECHOED and COOKIE-WAIT 1486 * 1487 * Unless otherwise stated, upon reception of an unexpected INIT for 1488 * this association, the endpoint shall generate an INIT ACK with a 1489 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1490 * current Verification Tag and peer's Verification Tag into a reserved 1491 * place within the state cookie. We shall refer to these locations as 1492 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1493 * containing this INIT ACK MUST carry a Verification Tag value equal to 1494 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1495 * MUST contain a new Initiation Tag (randomly generated see Section 1496 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1497 * existing parameters of the association (e.g. number of outbound 1498 * streams) into the INIT ACK and cookie. 1499 * 1500 * After sending out the INIT ACK, the endpoint shall take no further 1501 * actions, i.e., the existing association, including its current state, 1502 * and the corresponding TCB MUST NOT be changed. 1503 * 1504 * Note: Only when a TCB exists and the association is not in a COOKIE- 1505 * WAIT state are the Tie-Tags populated. For a normal association INIT 1506 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1507 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1508 * State Cookie are populated as specified in section 5.2.1. 1509 * 1510 * Verification Tag: Not specified, but an INIT has no way of knowing 1511 * what the verification tag could be, so we ignore it. 1512 * 1513 * Inputs 1514 * (endpoint, asoc, chunk) 1515 * 1516 * Outputs 1517 * (asoc, reply_msg, msg_up, timers, counters) 1518 * 1519 * The return value is the disposition of the chunk. 1520 */ 1521 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1522 const struct sctp_association *asoc, 1523 const sctp_subtype_t type, 1524 void *arg, 1525 sctp_cmd_seq_t *commands) 1526 { 1527 /* Call helper to do the real work for both simulataneous and 1528 * duplicate INIT chunk handling. 1529 */ 1530 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1531 } 1532 1533 1534 /* 1535 * Unexpected INIT-ACK handler. 1536 * 1537 * Section 5.2.3 1538 * If an INIT ACK received by an endpoint in any state other than the 1539 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1540 * An unexpected INIT ACK usually indicates the processing of an old or 1541 * duplicated INIT chunk. 1542 */ 1543 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep, 1544 const struct sctp_association *asoc, 1545 const sctp_subtype_t type, 1546 void *arg, sctp_cmd_seq_t *commands) 1547 { 1548 /* Per the above section, we'll discard the chunk if we have an 1549 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1550 */ 1551 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 1552 return sctp_sf_ootb(ep, asoc, type, arg, commands); 1553 else 1554 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 1555 } 1556 1557 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1558 * 1559 * Section 5.2.4 1560 * A) In this case, the peer may have restarted. 1561 */ 1562 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1563 const struct sctp_association *asoc, 1564 struct sctp_chunk *chunk, 1565 sctp_cmd_seq_t *commands, 1566 struct sctp_association *new_asoc) 1567 { 1568 sctp_init_chunk_t *peer_init; 1569 struct sctp_ulpevent *ev; 1570 struct sctp_chunk *repl; 1571 struct sctp_chunk *err; 1572 sctp_disposition_t disposition; 1573 1574 /* new_asoc is a brand-new association, so these are not yet 1575 * side effects--it is safe to run them here. 1576 */ 1577 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1578 1579 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1580 sctp_source(chunk), peer_init, 1581 GFP_ATOMIC)) 1582 goto nomem; 1583 1584 /* Make sure no new addresses are being added during the 1585 * restart. Though this is a pretty complicated attack 1586 * since you'd have to get inside the cookie. 1587 */ 1588 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1589 return SCTP_DISPOSITION_CONSUME; 1590 } 1591 1592 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1593 * the peer has restarted (Action A), it MUST NOT setup a new 1594 * association but instead resend the SHUTDOWN ACK and send an ERROR 1595 * chunk with a "Cookie Received while Shutting Down" error cause to 1596 * its peer. 1597 */ 1598 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1599 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1600 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1601 chunk, commands); 1602 if (SCTP_DISPOSITION_NOMEM == disposition) 1603 goto nomem; 1604 1605 err = sctp_make_op_error(asoc, chunk, 1606 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1607 NULL, 0); 1608 if (err) 1609 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1610 SCTP_CHUNK(err)); 1611 1612 return SCTP_DISPOSITION_CONSUME; 1613 } 1614 1615 /* For now, fail any unsent/unacked data. Consider the optional 1616 * choice of resending of this data. 1617 */ 1618 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1619 1620 repl = sctp_make_cookie_ack(new_asoc, chunk); 1621 if (!repl) 1622 goto nomem; 1623 1624 /* Report association restart to upper layer. */ 1625 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1626 new_asoc->c.sinit_num_ostreams, 1627 new_asoc->c.sinit_max_instreams, 1628 NULL, GFP_ATOMIC); 1629 if (!ev) 1630 goto nomem_ev; 1631 1632 /* Update the content of current association. */ 1633 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1634 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1635 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1636 return SCTP_DISPOSITION_CONSUME; 1637 1638 nomem_ev: 1639 sctp_chunk_free(repl); 1640 nomem: 1641 return SCTP_DISPOSITION_NOMEM; 1642 } 1643 1644 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1645 * 1646 * Section 5.2.4 1647 * B) In this case, both sides may be attempting to start an association 1648 * at about the same time but the peer endpoint started its INIT 1649 * after responding to the local endpoint's INIT 1650 */ 1651 /* This case represents an initialization collision. */ 1652 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1653 const struct sctp_association *asoc, 1654 struct sctp_chunk *chunk, 1655 sctp_cmd_seq_t *commands, 1656 struct sctp_association *new_asoc) 1657 { 1658 sctp_init_chunk_t *peer_init; 1659 struct sctp_chunk *repl; 1660 1661 /* new_asoc is a brand-new association, so these are not yet 1662 * side effects--it is safe to run them here. 1663 */ 1664 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1665 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1666 sctp_source(chunk), peer_init, 1667 GFP_ATOMIC)) 1668 goto nomem; 1669 1670 /* Update the content of current association. */ 1671 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1672 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1673 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1674 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1675 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1676 1677 repl = sctp_make_cookie_ack(new_asoc, chunk); 1678 if (!repl) 1679 goto nomem; 1680 1681 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1682 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1683 1684 /* RFC 2960 5.1 Normal Establishment of an Association 1685 * 1686 * D) IMPLEMENTATION NOTE: An implementation may choose to 1687 * send the Communication Up notification to the SCTP user 1688 * upon reception of a valid COOKIE ECHO chunk. 1689 * 1690 * Sadly, this needs to be implemented as a side-effect, because 1691 * we are not guaranteed to have set the association id of the real 1692 * association and so these notifications need to be delayed until 1693 * the association id is allocated. 1694 */ 1695 1696 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1697 1698 /* Sockets API Draft Section 5.3.1.6 1699 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1700 * delivers this notification to inform the application that of the 1701 * peers requested adaptation layer. 1702 * 1703 * This also needs to be done as a side effect for the same reason as 1704 * above. 1705 */ 1706 if (asoc->peer.adaptation_ind) 1707 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1708 1709 return SCTP_DISPOSITION_CONSUME; 1710 1711 nomem: 1712 return SCTP_DISPOSITION_NOMEM; 1713 } 1714 1715 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1716 * 1717 * Section 5.2.4 1718 * C) In this case, the local endpoint's cookie has arrived late. 1719 * Before it arrived, the local endpoint sent an INIT and received an 1720 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1721 * but a new tag of its own. 1722 */ 1723 /* This case represents an initialization collision. */ 1724 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1725 const struct sctp_association *asoc, 1726 struct sctp_chunk *chunk, 1727 sctp_cmd_seq_t *commands, 1728 struct sctp_association *new_asoc) 1729 { 1730 /* The cookie should be silently discarded. 1731 * The endpoint SHOULD NOT change states and should leave 1732 * any timers running. 1733 */ 1734 return SCTP_DISPOSITION_DISCARD; 1735 } 1736 1737 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1738 * 1739 * Section 5.2.4 1740 * 1741 * D) When both local and remote tags match the endpoint should always 1742 * enter the ESTABLISHED state, if it has not already done so. 1743 */ 1744 /* This case represents an initialization collision. */ 1745 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1746 const struct sctp_association *asoc, 1747 struct sctp_chunk *chunk, 1748 sctp_cmd_seq_t *commands, 1749 struct sctp_association *new_asoc) 1750 { 1751 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1752 struct sctp_chunk *repl; 1753 1754 /* Clarification from Implementor's Guide: 1755 * D) When both local and remote tags match the endpoint should 1756 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1757 * It should stop any cookie timer that may be running and send 1758 * a COOKIE ACK. 1759 */ 1760 1761 /* Don't accidentally move back into established state. */ 1762 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1763 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1764 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1765 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1766 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1767 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1768 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1769 SCTP_NULL()); 1770 1771 /* RFC 2960 5.1 Normal Establishment of an Association 1772 * 1773 * D) IMPLEMENTATION NOTE: An implementation may choose 1774 * to send the Communication Up notification to the 1775 * SCTP user upon reception of a valid COOKIE 1776 * ECHO chunk. 1777 */ 1778 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1779 SCTP_COMM_UP, 0, 1780 asoc->c.sinit_num_ostreams, 1781 asoc->c.sinit_max_instreams, 1782 NULL, GFP_ATOMIC); 1783 if (!ev) 1784 goto nomem; 1785 1786 /* Sockets API Draft Section 5.3.1.6 1787 * When a peer sends a Adaptation Layer Indication parameter, 1788 * SCTP delivers this notification to inform the application 1789 * that of the peers requested adaptation layer. 1790 */ 1791 if (asoc->peer.adaptation_ind) { 1792 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1793 GFP_ATOMIC); 1794 if (!ai_ev) 1795 goto nomem; 1796 1797 } 1798 } 1799 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1800 1801 repl = sctp_make_cookie_ack(new_asoc, chunk); 1802 if (!repl) 1803 goto nomem; 1804 1805 if (ev) 1806 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1807 SCTP_ULPEVENT(ev)); 1808 if (ai_ev) 1809 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1810 SCTP_ULPEVENT(ai_ev)); 1811 1812 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1813 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1814 1815 return SCTP_DISPOSITION_CONSUME; 1816 1817 nomem: 1818 if (ai_ev) 1819 sctp_ulpevent_free(ai_ev); 1820 if (ev) 1821 sctp_ulpevent_free(ev); 1822 return SCTP_DISPOSITION_NOMEM; 1823 } 1824 1825 /* 1826 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1827 * chunk was retransmitted and then delayed in the network. 1828 * 1829 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1830 * 1831 * Verification Tag: None. Do cookie validation. 1832 * 1833 * Inputs 1834 * (endpoint, asoc, chunk) 1835 * 1836 * Outputs 1837 * (asoc, reply_msg, msg_up, timers, counters) 1838 * 1839 * The return value is the disposition of the chunk. 1840 */ 1841 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1842 const struct sctp_association *asoc, 1843 const sctp_subtype_t type, 1844 void *arg, 1845 sctp_cmd_seq_t *commands) 1846 { 1847 sctp_disposition_t retval; 1848 struct sctp_chunk *chunk = arg; 1849 struct sctp_association *new_asoc; 1850 int error = 0; 1851 char action; 1852 struct sctp_chunk *err_chk_p; 1853 1854 /* Make sure that the chunk has a valid length from the protocol 1855 * perspective. In this case check to make sure we have at least 1856 * enough for the chunk header. Cookie length verification is 1857 * done later. 1858 */ 1859 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1860 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1861 commands); 1862 1863 /* "Decode" the chunk. We have no optional parameters so we 1864 * are in good shape. 1865 */ 1866 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1867 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1868 sizeof(sctp_chunkhdr_t))) 1869 goto nomem; 1870 1871 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1872 * of a duplicate COOKIE ECHO match the Verification Tags of the 1873 * current association, consider the State Cookie valid even if 1874 * the lifespan is exceeded. 1875 */ 1876 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1877 &err_chk_p); 1878 1879 /* FIXME: 1880 * If the re-build failed, what is the proper error path 1881 * from here? 1882 * 1883 * [We should abort the association. --piggy] 1884 */ 1885 if (!new_asoc) { 1886 /* FIXME: Several errors are possible. A bad cookie should 1887 * be silently discarded, but think about logging it too. 1888 */ 1889 switch (error) { 1890 case -SCTP_IERROR_NOMEM: 1891 goto nomem; 1892 1893 case -SCTP_IERROR_STALE_COOKIE: 1894 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 1895 err_chk_p); 1896 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1897 case -SCTP_IERROR_BAD_SIG: 1898 default: 1899 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1900 } 1901 } 1902 1903 /* Compare the tie_tag in cookie with the verification tag of 1904 * current association. 1905 */ 1906 action = sctp_tietags_compare(new_asoc, asoc); 1907 1908 switch (action) { 1909 case 'A': /* Association restart. */ 1910 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 1911 new_asoc); 1912 break; 1913 1914 case 'B': /* Collision case B. */ 1915 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 1916 new_asoc); 1917 break; 1918 1919 case 'C': /* Collision case C. */ 1920 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 1921 new_asoc); 1922 break; 1923 1924 case 'D': /* Collision case D. */ 1925 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 1926 new_asoc); 1927 break; 1928 1929 default: /* Discard packet for all others. */ 1930 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1931 break; 1932 } 1933 1934 /* Delete the tempory new association. */ 1935 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1936 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1937 1938 return retval; 1939 1940 nomem: 1941 return SCTP_DISPOSITION_NOMEM; 1942 } 1943 1944 /* 1945 * Process an ABORT. (SHUTDOWN-PENDING state) 1946 * 1947 * See sctp_sf_do_9_1_abort(). 1948 */ 1949 sctp_disposition_t sctp_sf_shutdown_pending_abort( 1950 const struct sctp_endpoint *ep, 1951 const struct sctp_association *asoc, 1952 const sctp_subtype_t type, 1953 void *arg, 1954 sctp_cmd_seq_t *commands) 1955 { 1956 struct sctp_chunk *chunk = arg; 1957 1958 if (!sctp_vtag_verify_either(chunk, asoc)) 1959 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1960 1961 /* Make sure that the ABORT chunk has a valid length. 1962 * Since this is an ABORT chunk, we have to discard it 1963 * because of the following text: 1964 * RFC 2960, Section 3.3.7 1965 * If an endpoint receives an ABORT with a format error or for an 1966 * association that doesn't exist, it MUST silently discard it. 1967 * Becasue the length is "invalid", we can't really discard just 1968 * as we do not know its true length. So, to be safe, discard the 1969 * packet. 1970 */ 1971 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 1972 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1973 1974 /* Stop the T5-shutdown guard timer. */ 1975 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1976 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 1977 1978 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 1979 } 1980 1981 /* 1982 * Process an ABORT. (SHUTDOWN-SENT state) 1983 * 1984 * See sctp_sf_do_9_1_abort(). 1985 */ 1986 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 1987 const struct sctp_association *asoc, 1988 const sctp_subtype_t type, 1989 void *arg, 1990 sctp_cmd_seq_t *commands) 1991 { 1992 struct sctp_chunk *chunk = arg; 1993 1994 if (!sctp_vtag_verify_either(chunk, asoc)) 1995 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1996 1997 /* Make sure that the ABORT chunk has a valid length. 1998 * Since this is an ABORT chunk, we have to discard it 1999 * because of the following text: 2000 * RFC 2960, Section 3.3.7 2001 * If an endpoint receives an ABORT with a format error or for an 2002 * association that doesn't exist, it MUST silently discard it. 2003 * Becasue the length is "invalid", we can't really discard just 2004 * as we do not know its true length. So, to be safe, discard the 2005 * packet. 2006 */ 2007 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2008 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2009 2010 /* Stop the T2-shutdown timer. */ 2011 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2012 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2013 2014 /* Stop the T5-shutdown guard timer. */ 2015 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2016 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2017 2018 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2019 } 2020 2021 /* 2022 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2023 * 2024 * See sctp_sf_do_9_1_abort(). 2025 */ 2026 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2027 const struct sctp_endpoint *ep, 2028 const struct sctp_association *asoc, 2029 const sctp_subtype_t type, 2030 void *arg, 2031 sctp_cmd_seq_t *commands) 2032 { 2033 /* The same T2 timer, so we should be able to use 2034 * common function with the SHUTDOWN-SENT state. 2035 */ 2036 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2037 } 2038 2039 /* 2040 * Handle an Error received in COOKIE_ECHOED state. 2041 * 2042 * Only handle the error type of stale COOKIE Error, the other errors will 2043 * be ignored. 2044 * 2045 * Inputs 2046 * (endpoint, asoc, chunk) 2047 * 2048 * Outputs 2049 * (asoc, reply_msg, msg_up, timers, counters) 2050 * 2051 * The return value is the disposition of the chunk. 2052 */ 2053 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2054 const struct sctp_association *asoc, 2055 const sctp_subtype_t type, 2056 void *arg, 2057 sctp_cmd_seq_t *commands) 2058 { 2059 struct sctp_chunk *chunk = arg; 2060 sctp_errhdr_t *err; 2061 2062 if (!sctp_vtag_verify(chunk, asoc)) 2063 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2064 2065 /* Make sure that the ERROR chunk has a valid length. 2066 * The parameter walking depends on this as well. 2067 */ 2068 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2069 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2070 commands); 2071 2072 /* Process the error here */ 2073 /* FUTURE FIXME: When PR-SCTP related and other optional 2074 * parms are emitted, this will have to change to handle multiple 2075 * errors. 2076 */ 2077 sctp_walk_errors(err, chunk->chunk_hdr) { 2078 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2079 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2080 arg, commands); 2081 } 2082 2083 /* It is possible to have malformed error causes, and that 2084 * will cause us to end the walk early. However, since 2085 * we are discarding the packet, there should be no adverse 2086 * affects. 2087 */ 2088 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2089 } 2090 2091 /* 2092 * Handle a Stale COOKIE Error 2093 * 2094 * Section: 5.2.6 Handle Stale COOKIE Error 2095 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2096 * one of the following three alternatives. 2097 * ... 2098 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2099 * Preservative parameter requesting an extension to the lifetime of 2100 * the State Cookie. When calculating the time extension, an 2101 * implementation SHOULD use the RTT information measured based on the 2102 * previous COOKIE ECHO / ERROR exchange, and should add no more 2103 * than 1 second beyond the measured RTT, due to long State Cookie 2104 * lifetimes making the endpoint more subject to a replay attack. 2105 * 2106 * Verification Tag: Not explicit, but safe to ignore. 2107 * 2108 * Inputs 2109 * (endpoint, asoc, chunk) 2110 * 2111 * Outputs 2112 * (asoc, reply_msg, msg_up, timers, counters) 2113 * 2114 * The return value is the disposition of the chunk. 2115 */ 2116 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2117 const struct sctp_association *asoc, 2118 const sctp_subtype_t type, 2119 void *arg, 2120 sctp_cmd_seq_t *commands) 2121 { 2122 struct sctp_chunk *chunk = arg; 2123 time_t stale; 2124 sctp_cookie_preserve_param_t bht; 2125 sctp_errhdr_t *err; 2126 struct sctp_chunk *reply; 2127 struct sctp_bind_addr *bp; 2128 int attempts = asoc->init_err_counter + 1; 2129 2130 if (attempts > asoc->max_init_attempts) { 2131 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2132 SCTP_ERROR(ETIMEDOUT)); 2133 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2134 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2135 return SCTP_DISPOSITION_DELETE_TCB; 2136 } 2137 2138 err = (sctp_errhdr_t *)(chunk->skb->data); 2139 2140 /* When calculating the time extension, an implementation 2141 * SHOULD use the RTT information measured based on the 2142 * previous COOKIE ECHO / ERROR exchange, and should add no 2143 * more than 1 second beyond the measured RTT, due to long 2144 * State Cookie lifetimes making the endpoint more subject to 2145 * a replay attack. 2146 * Measure of Staleness's unit is usec. (1/1000000 sec) 2147 * Suggested Cookie Life-span Increment's unit is msec. 2148 * (1/1000 sec) 2149 * In general, if you use the suggested cookie life, the value 2150 * found in the field of measure of staleness should be doubled 2151 * to give ample time to retransmit the new cookie and thus 2152 * yield a higher probability of success on the reattempt. 2153 */ 2154 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2155 stale = (stale * 2) / 1000; 2156 2157 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2158 bht.param_hdr.length = htons(sizeof(bht)); 2159 bht.lifespan_increment = htonl(stale); 2160 2161 /* Build that new INIT chunk. */ 2162 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2163 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2164 if (!reply) 2165 goto nomem; 2166 2167 sctp_addto_chunk(reply, sizeof(bht), &bht); 2168 2169 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2170 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2171 2172 /* Stop pending T3-rtx and heartbeat timers */ 2173 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2174 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2175 2176 /* Delete non-primary peer ip addresses since we are transitioning 2177 * back to the COOKIE-WAIT state 2178 */ 2179 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2180 2181 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2182 * resend 2183 */ 2184 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, 2185 SCTP_TRANSPORT(asoc->peer.primary_path)); 2186 2187 /* Cast away the const modifier, as we want to just 2188 * rerun it through as a sideffect. 2189 */ 2190 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2191 2192 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2193 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2194 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2195 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2196 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2197 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2198 2199 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2200 2201 return SCTP_DISPOSITION_CONSUME; 2202 2203 nomem: 2204 return SCTP_DISPOSITION_NOMEM; 2205 } 2206 2207 /* 2208 * Process an ABORT. 2209 * 2210 * Section: 9.1 2211 * After checking the Verification Tag, the receiving endpoint shall 2212 * remove the association from its record, and shall report the 2213 * termination to its upper layer. 2214 * 2215 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2216 * B) Rules for packet carrying ABORT: 2217 * 2218 * - The endpoint shall always fill in the Verification Tag field of the 2219 * outbound packet with the destination endpoint's tag value if it 2220 * is known. 2221 * 2222 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2223 * MUST follow the procedure described in Section 8.4. 2224 * 2225 * - The receiver MUST accept the packet if the Verification Tag 2226 * matches either its own tag, OR the tag of its peer. Otherwise, the 2227 * receiver MUST silently discard the packet and take no further 2228 * action. 2229 * 2230 * Inputs 2231 * (endpoint, asoc, chunk) 2232 * 2233 * Outputs 2234 * (asoc, reply_msg, msg_up, timers, counters) 2235 * 2236 * The return value is the disposition of the chunk. 2237 */ 2238 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2239 const struct sctp_association *asoc, 2240 const sctp_subtype_t type, 2241 void *arg, 2242 sctp_cmd_seq_t *commands) 2243 { 2244 struct sctp_chunk *chunk = arg; 2245 unsigned len; 2246 __be16 error = SCTP_ERROR_NO_ERROR; 2247 2248 if (!sctp_vtag_verify_either(chunk, asoc)) 2249 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2250 2251 /* Make sure that the ABORT chunk has a valid length. 2252 * Since this is an ABORT chunk, we have to discard it 2253 * because of the following text: 2254 * RFC 2960, Section 3.3.7 2255 * If an endpoint receives an ABORT with a format error or for an 2256 * association that doesn't exist, it MUST silently discard it. 2257 * Becasue the length is "invalid", we can't really discard just 2258 * as we do not know its true length. So, to be safe, discard the 2259 * packet. 2260 */ 2261 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2262 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2263 2264 /* See if we have an error cause code in the chunk. */ 2265 len = ntohs(chunk->chunk_hdr->length); 2266 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2267 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2268 2269 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2270 /* ASSOC_FAILED will DELETE_TCB. */ 2271 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2272 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2273 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2274 2275 return SCTP_DISPOSITION_ABORT; 2276 } 2277 2278 /* 2279 * Process an ABORT. (COOKIE-WAIT state) 2280 * 2281 * See sctp_sf_do_9_1_abort() above. 2282 */ 2283 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2284 const struct sctp_association *asoc, 2285 const sctp_subtype_t type, 2286 void *arg, 2287 sctp_cmd_seq_t *commands) 2288 { 2289 struct sctp_chunk *chunk = arg; 2290 unsigned len; 2291 __be16 error = SCTP_ERROR_NO_ERROR; 2292 2293 if (!sctp_vtag_verify_either(chunk, asoc)) 2294 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2295 2296 /* Make sure that the ABORT chunk has a valid length. 2297 * Since this is an ABORT chunk, we have to discard it 2298 * because of the following text: 2299 * RFC 2960, Section 3.3.7 2300 * If an endpoint receives an ABORT with a format error or for an 2301 * association that doesn't exist, it MUST silently discard it. 2302 * Becasue the length is "invalid", we can't really discard just 2303 * as we do not know its true length. So, to be safe, discard the 2304 * packet. 2305 */ 2306 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2307 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2308 2309 /* See if we have an error cause code in the chunk. */ 2310 len = ntohs(chunk->chunk_hdr->length); 2311 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2312 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2313 2314 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, 2315 chunk->transport); 2316 } 2317 2318 /* 2319 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2320 */ 2321 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2322 const struct sctp_association *asoc, 2323 const sctp_subtype_t type, 2324 void *arg, 2325 sctp_cmd_seq_t *commands) 2326 { 2327 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, 2328 ENOPROTOOPT, asoc, 2329 (struct sctp_transport *)arg); 2330 } 2331 2332 /* 2333 * Process an ABORT. (COOKIE-ECHOED state) 2334 */ 2335 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2336 const struct sctp_association *asoc, 2337 const sctp_subtype_t type, 2338 void *arg, 2339 sctp_cmd_seq_t *commands) 2340 { 2341 /* There is a single T1 timer, so we should be able to use 2342 * common function with the COOKIE-WAIT state. 2343 */ 2344 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2345 } 2346 2347 /* 2348 * Stop T1 timer and abort association with "INIT failed". 2349 * 2350 * This is common code called by several sctp_sf_*_abort() functions above. 2351 */ 2352 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2353 __be16 error, int sk_err, 2354 const struct sctp_association *asoc, 2355 struct sctp_transport *transport) 2356 { 2357 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2358 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2359 SCTP_STATE(SCTP_STATE_CLOSED)); 2360 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2361 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2362 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2363 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2364 /* CMD_INIT_FAILED will DELETE_TCB. */ 2365 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2366 SCTP_PERR(error)); 2367 return SCTP_DISPOSITION_ABORT; 2368 } 2369 2370 /* 2371 * sctp_sf_do_9_2_shut 2372 * 2373 * Section: 9.2 2374 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2375 * - enter the SHUTDOWN-RECEIVED state, 2376 * 2377 * - stop accepting new data from its SCTP user 2378 * 2379 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2380 * that all its outstanding DATA chunks have been received by the 2381 * SHUTDOWN sender. 2382 * 2383 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2384 * send a SHUTDOWN in response to a ULP request. And should discard 2385 * subsequent SHUTDOWN chunks. 2386 * 2387 * If there are still outstanding DATA chunks left, the SHUTDOWN 2388 * receiver shall continue to follow normal data transmission 2389 * procedures defined in Section 6 until all outstanding DATA chunks 2390 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2391 * new data from its SCTP user. 2392 * 2393 * Verification Tag: 8.5 Verification Tag [Normal verification] 2394 * 2395 * Inputs 2396 * (endpoint, asoc, chunk) 2397 * 2398 * Outputs 2399 * (asoc, reply_msg, msg_up, timers, counters) 2400 * 2401 * The return value is the disposition of the chunk. 2402 */ 2403 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2404 const struct sctp_association *asoc, 2405 const sctp_subtype_t type, 2406 void *arg, 2407 sctp_cmd_seq_t *commands) 2408 { 2409 struct sctp_chunk *chunk = arg; 2410 sctp_shutdownhdr_t *sdh; 2411 sctp_disposition_t disposition; 2412 struct sctp_ulpevent *ev; 2413 2414 if (!sctp_vtag_verify(chunk, asoc)) 2415 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2416 2417 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2418 if (!sctp_chunk_length_valid(chunk, 2419 sizeof(struct sctp_shutdown_chunk_t))) 2420 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2421 commands); 2422 2423 /* Convert the elaborate header. */ 2424 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2425 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2426 chunk->subh.shutdown_hdr = sdh; 2427 2428 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2429 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2430 * inform the application that it should cease sending data. 2431 */ 2432 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2433 if (!ev) { 2434 disposition = SCTP_DISPOSITION_NOMEM; 2435 goto out; 2436 } 2437 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2438 2439 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2440 * - enter the SHUTDOWN-RECEIVED state, 2441 * - stop accepting new data from its SCTP user 2442 * 2443 * [This is implicit in the new state.] 2444 */ 2445 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2446 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2447 disposition = SCTP_DISPOSITION_CONSUME; 2448 2449 if (sctp_outq_is_empty(&asoc->outqueue)) { 2450 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2451 arg, commands); 2452 } 2453 2454 if (SCTP_DISPOSITION_NOMEM == disposition) 2455 goto out; 2456 2457 /* - verify, by checking the Cumulative TSN Ack field of the 2458 * chunk, that all its outstanding DATA chunks have been 2459 * received by the SHUTDOWN sender. 2460 */ 2461 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2462 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2463 2464 out: 2465 return disposition; 2466 } 2467 2468 /* RFC 2960 9.2 2469 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2470 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2471 * transport addresses (either in the IP addresses or in the INIT chunk) 2472 * that belong to this association, it should discard the INIT chunk and 2473 * retransmit the SHUTDOWN ACK chunk. 2474 */ 2475 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2476 const struct sctp_association *asoc, 2477 const sctp_subtype_t type, 2478 void *arg, 2479 sctp_cmd_seq_t *commands) 2480 { 2481 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2482 struct sctp_chunk *reply; 2483 2484 /* Since we are not going to really process this INIT, there 2485 * is no point in verifying chunk boundries. Just generate 2486 * the SHUTDOWN ACK. 2487 */ 2488 reply = sctp_make_shutdown_ack(asoc, chunk); 2489 if (NULL == reply) 2490 goto nomem; 2491 2492 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2493 * the T2-SHUTDOWN timer. 2494 */ 2495 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2496 2497 /* and restart the T2-shutdown timer. */ 2498 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2499 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2500 2501 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2502 2503 return SCTP_DISPOSITION_CONSUME; 2504 nomem: 2505 return SCTP_DISPOSITION_NOMEM; 2506 } 2507 2508 /* 2509 * sctp_sf_do_ecn_cwr 2510 * 2511 * Section: Appendix A: Explicit Congestion Notification 2512 * 2513 * CWR: 2514 * 2515 * RFC 2481 details a specific bit for a sender to send in the header of 2516 * its next outbound TCP segment to indicate to its peer that it has 2517 * reduced its congestion window. This is termed the CWR bit. For 2518 * SCTP the same indication is made by including the CWR chunk. 2519 * This chunk contains one data element, i.e. the TSN number that 2520 * was sent in the ECNE chunk. This element represents the lowest 2521 * TSN number in the datagram that was originally marked with the 2522 * CE bit. 2523 * 2524 * Verification Tag: 8.5 Verification Tag [Normal verification] 2525 * Inputs 2526 * (endpoint, asoc, chunk) 2527 * 2528 * Outputs 2529 * (asoc, reply_msg, msg_up, timers, counters) 2530 * 2531 * The return value is the disposition of the chunk. 2532 */ 2533 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2534 const struct sctp_association *asoc, 2535 const sctp_subtype_t type, 2536 void *arg, 2537 sctp_cmd_seq_t *commands) 2538 { 2539 sctp_cwrhdr_t *cwr; 2540 struct sctp_chunk *chunk = arg; 2541 u32 lowest_tsn; 2542 2543 if (!sctp_vtag_verify(chunk, asoc)) 2544 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2545 2546 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2547 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2548 commands); 2549 2550 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2551 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2552 2553 lowest_tsn = ntohl(cwr->lowest_tsn); 2554 2555 /* Does this CWR ack the last sent congestion notification? */ 2556 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2557 /* Stop sending ECNE. */ 2558 sctp_add_cmd_sf(commands, 2559 SCTP_CMD_ECN_CWR, 2560 SCTP_U32(lowest_tsn)); 2561 } 2562 return SCTP_DISPOSITION_CONSUME; 2563 } 2564 2565 /* 2566 * sctp_sf_do_ecne 2567 * 2568 * Section: Appendix A: Explicit Congestion Notification 2569 * 2570 * ECN-Echo 2571 * 2572 * RFC 2481 details a specific bit for a receiver to send back in its 2573 * TCP acknowledgements to notify the sender of the Congestion 2574 * Experienced (CE) bit having arrived from the network. For SCTP this 2575 * same indication is made by including the ECNE chunk. This chunk 2576 * contains one data element, i.e. the lowest TSN associated with the IP 2577 * datagram marked with the CE bit..... 2578 * 2579 * Verification Tag: 8.5 Verification Tag [Normal verification] 2580 * Inputs 2581 * (endpoint, asoc, chunk) 2582 * 2583 * Outputs 2584 * (asoc, reply_msg, msg_up, timers, counters) 2585 * 2586 * The return value is the disposition of the chunk. 2587 */ 2588 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2589 const struct sctp_association *asoc, 2590 const sctp_subtype_t type, 2591 void *arg, 2592 sctp_cmd_seq_t *commands) 2593 { 2594 sctp_ecnehdr_t *ecne; 2595 struct sctp_chunk *chunk = arg; 2596 2597 if (!sctp_vtag_verify(chunk, asoc)) 2598 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2599 2600 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2601 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2602 commands); 2603 2604 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2605 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2606 2607 /* If this is a newer ECNE than the last CWR packet we sent out */ 2608 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2609 SCTP_U32(ntohl(ecne->lowest_tsn))); 2610 2611 return SCTP_DISPOSITION_CONSUME; 2612 } 2613 2614 /* 2615 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2616 * 2617 * The SCTP endpoint MUST always acknowledge the reception of each valid 2618 * DATA chunk. 2619 * 2620 * The guidelines on delayed acknowledgement algorithm specified in 2621 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2622 * acknowledgement SHOULD be generated for at least every second packet 2623 * (not every second DATA chunk) received, and SHOULD be generated within 2624 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2625 * situations it may be beneficial for an SCTP transmitter to be more 2626 * conservative than the algorithms detailed in this document allow. 2627 * However, an SCTP transmitter MUST NOT be more aggressive than the 2628 * following algorithms allow. 2629 * 2630 * A SCTP receiver MUST NOT generate more than one SACK for every 2631 * incoming packet, other than to update the offered window as the 2632 * receiving application consumes new data. 2633 * 2634 * Verification Tag: 8.5 Verification Tag [Normal verification] 2635 * 2636 * Inputs 2637 * (endpoint, asoc, chunk) 2638 * 2639 * Outputs 2640 * (asoc, reply_msg, msg_up, timers, counters) 2641 * 2642 * The return value is the disposition of the chunk. 2643 */ 2644 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2645 const struct sctp_association *asoc, 2646 const sctp_subtype_t type, 2647 void *arg, 2648 sctp_cmd_seq_t *commands) 2649 { 2650 struct sctp_chunk *chunk = arg; 2651 int error; 2652 2653 if (!sctp_vtag_verify(chunk, asoc)) { 2654 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2655 SCTP_NULL()); 2656 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2657 } 2658 2659 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2660 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2661 commands); 2662 2663 error = sctp_eat_data(asoc, chunk, commands ); 2664 switch (error) { 2665 case SCTP_IERROR_NO_ERROR: 2666 break; 2667 case SCTP_IERROR_HIGH_TSN: 2668 case SCTP_IERROR_BAD_STREAM: 2669 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2670 goto discard_noforce; 2671 case SCTP_IERROR_DUP_TSN: 2672 case SCTP_IERROR_IGNORE_TSN: 2673 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2674 goto discard_force; 2675 case SCTP_IERROR_NO_DATA: 2676 goto consume; 2677 default: 2678 BUG(); 2679 } 2680 2681 if (asoc->autoclose) { 2682 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2683 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2684 } 2685 2686 /* If this is the last chunk in a packet, we need to count it 2687 * toward sack generation. Note that we need to SACK every 2688 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2689 * THEM. We elect to NOT generate SACK's if the chunk fails 2690 * the verification tag test. 2691 * 2692 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2693 * 2694 * The SCTP endpoint MUST always acknowledge the reception of 2695 * each valid DATA chunk. 2696 * 2697 * The guidelines on delayed acknowledgement algorithm 2698 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2699 * Specifically, an acknowledgement SHOULD be generated for at 2700 * least every second packet (not every second DATA chunk) 2701 * received, and SHOULD be generated within 200 ms of the 2702 * arrival of any unacknowledged DATA chunk. In some 2703 * situations it may be beneficial for an SCTP transmitter to 2704 * be more conservative than the algorithms detailed in this 2705 * document allow. However, an SCTP transmitter MUST NOT be 2706 * more aggressive than the following algorithms allow. 2707 */ 2708 if (chunk->end_of_packet) 2709 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2710 2711 return SCTP_DISPOSITION_CONSUME; 2712 2713 discard_force: 2714 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2715 * 2716 * When a packet arrives with duplicate DATA chunk(s) and with 2717 * no new DATA chunk(s), the endpoint MUST immediately send a 2718 * SACK with no delay. If a packet arrives with duplicate 2719 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2720 * MAY immediately send a SACK. Normally receipt of duplicate 2721 * DATA chunks will occur when the original SACK chunk was lost 2722 * and the peer's RTO has expired. The duplicate TSN number(s) 2723 * SHOULD be reported in the SACK as duplicate. 2724 */ 2725 /* In our case, we split the MAY SACK advice up whether or not 2726 * the last chunk is a duplicate.' 2727 */ 2728 if (chunk->end_of_packet) 2729 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2730 return SCTP_DISPOSITION_DISCARD; 2731 2732 discard_noforce: 2733 if (chunk->end_of_packet) 2734 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2735 2736 return SCTP_DISPOSITION_DISCARD; 2737 consume: 2738 return SCTP_DISPOSITION_CONSUME; 2739 2740 } 2741 2742 /* 2743 * sctp_sf_eat_data_fast_4_4 2744 * 2745 * Section: 4 (4) 2746 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2747 * DATA chunks without delay. 2748 * 2749 * Verification Tag: 8.5 Verification Tag [Normal verification] 2750 * Inputs 2751 * (endpoint, asoc, chunk) 2752 * 2753 * Outputs 2754 * (asoc, reply_msg, msg_up, timers, counters) 2755 * 2756 * The return value is the disposition of the chunk. 2757 */ 2758 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2759 const struct sctp_association *asoc, 2760 const sctp_subtype_t type, 2761 void *arg, 2762 sctp_cmd_seq_t *commands) 2763 { 2764 struct sctp_chunk *chunk = arg; 2765 int error; 2766 2767 if (!sctp_vtag_verify(chunk, asoc)) { 2768 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2769 SCTP_NULL()); 2770 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2771 } 2772 2773 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2774 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2775 commands); 2776 2777 error = sctp_eat_data(asoc, chunk, commands ); 2778 switch (error) { 2779 case SCTP_IERROR_NO_ERROR: 2780 case SCTP_IERROR_HIGH_TSN: 2781 case SCTP_IERROR_DUP_TSN: 2782 case SCTP_IERROR_IGNORE_TSN: 2783 case SCTP_IERROR_BAD_STREAM: 2784 break; 2785 case SCTP_IERROR_NO_DATA: 2786 goto consume; 2787 default: 2788 BUG(); 2789 } 2790 2791 /* Go a head and force a SACK, since we are shutting down. */ 2792 2793 /* Implementor's Guide. 2794 * 2795 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 2796 * respond to each received packet containing one or more DATA chunk(s) 2797 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 2798 */ 2799 if (chunk->end_of_packet) { 2800 /* We must delay the chunk creation since the cumulative 2801 * TSN has not been updated yet. 2802 */ 2803 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 2804 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2805 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2806 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2807 } 2808 2809 consume: 2810 return SCTP_DISPOSITION_CONSUME; 2811 } 2812 2813 /* 2814 * Section: 6.2 Processing a Received SACK 2815 * D) Any time a SACK arrives, the endpoint performs the following: 2816 * 2817 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 2818 * then drop the SACK. Since Cumulative TSN Ack is monotonically 2819 * increasing, a SACK whose Cumulative TSN Ack is less than the 2820 * Cumulative TSN Ack Point indicates an out-of-order SACK. 2821 * 2822 * ii) Set rwnd equal to the newly received a_rwnd minus the number 2823 * of bytes still outstanding after processing the Cumulative TSN Ack 2824 * and the Gap Ack Blocks. 2825 * 2826 * iii) If the SACK is missing a TSN that was previously 2827 * acknowledged via a Gap Ack Block (e.g., the data receiver 2828 * reneged on the data), then mark the corresponding DATA chunk 2829 * as available for retransmit: Mark it as missing for fast 2830 * retransmit as described in Section 7.2.4 and if no retransmit 2831 * timer is running for the destination address to which the DATA 2832 * chunk was originally transmitted, then T3-rtx is started for 2833 * that destination address. 2834 * 2835 * Verification Tag: 8.5 Verification Tag [Normal verification] 2836 * 2837 * Inputs 2838 * (endpoint, asoc, chunk) 2839 * 2840 * Outputs 2841 * (asoc, reply_msg, msg_up, timers, counters) 2842 * 2843 * The return value is the disposition of the chunk. 2844 */ 2845 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 2846 const struct sctp_association *asoc, 2847 const sctp_subtype_t type, 2848 void *arg, 2849 sctp_cmd_seq_t *commands) 2850 { 2851 struct sctp_chunk *chunk = arg; 2852 sctp_sackhdr_t *sackh; 2853 __u32 ctsn; 2854 2855 if (!sctp_vtag_verify(chunk, asoc)) 2856 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2857 2858 /* Make sure that the SACK chunk has a valid length. */ 2859 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 2860 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2861 commands); 2862 2863 /* Pull the SACK chunk from the data buffer */ 2864 sackh = sctp_sm_pull_sack(chunk); 2865 /* Was this a bogus SACK? */ 2866 if (!sackh) 2867 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2868 chunk->subh.sack_hdr = sackh; 2869 ctsn = ntohl(sackh->cum_tsn_ack); 2870 2871 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 2872 * Ack Point, then drop the SACK. Since Cumulative TSN 2873 * Ack is monotonically increasing, a SACK whose 2874 * Cumulative TSN Ack is less than the Cumulative TSN Ack 2875 * Point indicates an out-of-order SACK. 2876 */ 2877 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2878 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2879 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2880 return SCTP_DISPOSITION_DISCARD; 2881 } 2882 2883 /* Return this SACK for further processing. */ 2884 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 2885 2886 /* Note: We do the rest of the work on the PROCESS_SACK 2887 * sideeffect. 2888 */ 2889 return SCTP_DISPOSITION_CONSUME; 2890 } 2891 2892 /* 2893 * Generate an ABORT in response to a packet. 2894 * 2895 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 2896 * 2897 * 8) The receiver should respond to the sender of the OOTB packet with 2898 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 2899 * MUST fill in the Verification Tag field of the outbound packet 2900 * with the value found in the Verification Tag field of the OOTB 2901 * packet and set the T-bit in the Chunk Flags to indicate that the 2902 * Verification Tag is reflected. After sending this ABORT, the 2903 * receiver of the OOTB packet shall discard the OOTB packet and take 2904 * no further action. 2905 * 2906 * Verification Tag: 2907 * 2908 * The return value is the disposition of the chunk. 2909 */ 2910 sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 2911 const struct sctp_association *asoc, 2912 const sctp_subtype_t type, 2913 void *arg, 2914 sctp_cmd_seq_t *commands) 2915 { 2916 struct sctp_packet *packet = NULL; 2917 struct sctp_chunk *chunk = arg; 2918 struct sctp_chunk *abort; 2919 2920 packet = sctp_ootb_pkt_new(asoc, chunk); 2921 2922 if (packet) { 2923 /* Make an ABORT. The T bit will be set if the asoc 2924 * is NULL. 2925 */ 2926 abort = sctp_make_abort(asoc, chunk, 0); 2927 if (!abort) { 2928 sctp_ootb_pkt_free(packet); 2929 return SCTP_DISPOSITION_NOMEM; 2930 } 2931 2932 /* Reflect vtag if T-Bit is set */ 2933 if (sctp_test_T_bit(abort)) 2934 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 2935 2936 /* Set the skb to the belonging sock for accounting. */ 2937 abort->skb->sk = ep->base.sk; 2938 2939 sctp_packet_append_chunk(packet, abort); 2940 2941 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 2942 SCTP_PACKET(packet)); 2943 2944 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 2945 2946 return SCTP_DISPOSITION_CONSUME; 2947 } 2948 2949 return SCTP_DISPOSITION_NOMEM; 2950 } 2951 2952 /* 2953 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 2954 * event as ULP notification for each cause included in the chunk. 2955 * 2956 * API 5.3.1.3 - SCTP_REMOTE_ERROR 2957 * 2958 * The return value is the disposition of the chunk. 2959 */ 2960 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 2961 const struct sctp_association *asoc, 2962 const sctp_subtype_t type, 2963 void *arg, 2964 sctp_cmd_seq_t *commands) 2965 { 2966 struct sctp_chunk *chunk = arg; 2967 struct sctp_ulpevent *ev; 2968 2969 if (!sctp_vtag_verify(chunk, asoc)) 2970 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2971 2972 /* Make sure that the ERROR chunk has a valid length. */ 2973 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2974 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2975 commands); 2976 2977 while (chunk->chunk_end > chunk->skb->data) { 2978 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 2979 GFP_ATOMIC); 2980 if (!ev) 2981 goto nomem; 2982 2983 if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP, 2984 SCTP_ULPEVENT(ev))) { 2985 sctp_ulpevent_free(ev); 2986 goto nomem; 2987 } 2988 2989 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 2990 SCTP_CHUNK(chunk)); 2991 } 2992 return SCTP_DISPOSITION_CONSUME; 2993 2994 nomem: 2995 return SCTP_DISPOSITION_NOMEM; 2996 } 2997 2998 /* 2999 * Process an inbound SHUTDOWN ACK. 3000 * 3001 * From Section 9.2: 3002 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3003 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3004 * peer, and remove all record of the association. 3005 * 3006 * The return value is the disposition. 3007 */ 3008 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3009 const struct sctp_association *asoc, 3010 const sctp_subtype_t type, 3011 void *arg, 3012 sctp_cmd_seq_t *commands) 3013 { 3014 struct sctp_chunk *chunk = arg; 3015 struct sctp_chunk *reply; 3016 struct sctp_ulpevent *ev; 3017 3018 if (!sctp_vtag_verify(chunk, asoc)) 3019 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3020 3021 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3022 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3023 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3024 commands); 3025 /* 10.2 H) SHUTDOWN COMPLETE notification 3026 * 3027 * When SCTP completes the shutdown procedures (section 9.2) this 3028 * notification is passed to the upper layer. 3029 */ 3030 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3031 0, 0, 0, NULL, GFP_ATOMIC); 3032 if (!ev) 3033 goto nomem; 3034 3035 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3036 reply = sctp_make_shutdown_complete(asoc, chunk); 3037 if (!reply) 3038 goto nomem_chunk; 3039 3040 /* Do all the commands now (after allocation), so that we 3041 * have consistent state if memory allocation failes 3042 */ 3043 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3044 3045 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3046 * stop the T2-shutdown timer, 3047 */ 3048 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3049 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3050 3051 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3052 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3053 3054 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3055 SCTP_STATE(SCTP_STATE_CLOSED)); 3056 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3057 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3058 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3059 3060 /* ...and remove all record of the association. */ 3061 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3062 return SCTP_DISPOSITION_DELETE_TCB; 3063 3064 nomem_chunk: 3065 sctp_ulpevent_free(ev); 3066 nomem: 3067 return SCTP_DISPOSITION_NOMEM; 3068 } 3069 3070 /* 3071 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3072 * 3073 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3074 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3075 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3076 * packet must fill in the Verification Tag field of the outbound 3077 * packet with the Verification Tag received in the SHUTDOWN ACK and 3078 * set the T-bit in the Chunk Flags to indicate that the Verification 3079 * Tag is reflected. 3080 * 3081 * 8) The receiver should respond to the sender of the OOTB packet with 3082 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3083 * MUST fill in the Verification Tag field of the outbound packet 3084 * with the value found in the Verification Tag field of the OOTB 3085 * packet and set the T-bit in the Chunk Flags to indicate that the 3086 * Verification Tag is reflected. After sending this ABORT, the 3087 * receiver of the OOTB packet shall discard the OOTB packet and take 3088 * no further action. 3089 */ 3090 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3091 const struct sctp_association *asoc, 3092 const sctp_subtype_t type, 3093 void *arg, 3094 sctp_cmd_seq_t *commands) 3095 { 3096 struct sctp_chunk *chunk = arg; 3097 struct sk_buff *skb = chunk->skb; 3098 sctp_chunkhdr_t *ch; 3099 __u8 *ch_end; 3100 int ootb_shut_ack = 0; 3101 3102 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3103 3104 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3105 do { 3106 /* Break out if chunk length is less then minimal. */ 3107 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3108 break; 3109 3110 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3111 if (ch_end > skb_tail_pointer(skb)) 3112 break; 3113 3114 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3115 ootb_shut_ack = 1; 3116 3117 /* RFC 2960, Section 3.3.7 3118 * Moreover, under any circumstances, an endpoint that 3119 * receives an ABORT MUST NOT respond to that ABORT by 3120 * sending an ABORT of its own. 3121 */ 3122 if (SCTP_CID_ABORT == ch->type) 3123 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3124 3125 ch = (sctp_chunkhdr_t *) ch_end; 3126 } while (ch_end < skb_tail_pointer(skb)); 3127 3128 if (ootb_shut_ack) 3129 sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3130 else 3131 sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3132 3133 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3134 } 3135 3136 /* 3137 * Handle an "Out of the blue" SHUTDOWN ACK. 3138 * 3139 * Section: 8.4 5, sctpimpguide 2.41. 3140 * 3141 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3142 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3143 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3144 * packet must fill in the Verification Tag field of the outbound 3145 * packet with the Verification Tag received in the SHUTDOWN ACK and 3146 * set the T-bit in the Chunk Flags to indicate that the Verification 3147 * Tag is reflected. 3148 * 3149 * Inputs 3150 * (endpoint, asoc, type, arg, commands) 3151 * 3152 * Outputs 3153 * (sctp_disposition_t) 3154 * 3155 * The return value is the disposition of the chunk. 3156 */ 3157 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3158 const struct sctp_association *asoc, 3159 const sctp_subtype_t type, 3160 void *arg, 3161 sctp_cmd_seq_t *commands) 3162 { 3163 struct sctp_packet *packet = NULL; 3164 struct sctp_chunk *chunk = arg; 3165 struct sctp_chunk *shut; 3166 3167 packet = sctp_ootb_pkt_new(asoc, chunk); 3168 3169 if (packet) { 3170 /* Make an SHUTDOWN_COMPLETE. 3171 * The T bit will be set if the asoc is NULL. 3172 */ 3173 shut = sctp_make_shutdown_complete(asoc, chunk); 3174 if (!shut) { 3175 sctp_ootb_pkt_free(packet); 3176 return SCTP_DISPOSITION_NOMEM; 3177 } 3178 3179 /* Reflect vtag if T-Bit is set */ 3180 if (sctp_test_T_bit(shut)) 3181 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3182 3183 /* Set the skb to the belonging sock for accounting. */ 3184 shut->skb->sk = ep->base.sk; 3185 3186 sctp_packet_append_chunk(packet, shut); 3187 3188 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3189 SCTP_PACKET(packet)); 3190 3191 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3192 3193 /* If the chunk length is invalid, we don't want to process 3194 * the reset of the packet. 3195 */ 3196 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3197 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3198 3199 return SCTP_DISPOSITION_CONSUME; 3200 } 3201 3202 return SCTP_DISPOSITION_NOMEM; 3203 } 3204 3205 /* 3206 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3207 * 3208 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3209 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3210 * procedures in section 8.4 SHOULD be followed, in other words it 3211 * should be treated as an Out Of The Blue packet. 3212 * [This means that we do NOT check the Verification Tag on these 3213 * chunks. --piggy ] 3214 * 3215 */ 3216 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3217 const struct sctp_association *asoc, 3218 const sctp_subtype_t type, 3219 void *arg, 3220 sctp_cmd_seq_t *commands) 3221 { 3222 /* Although we do have an association in this case, it corresponds 3223 * to a restarted association. So the packet is treated as an OOTB 3224 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3225 * called with a NULL association. 3226 */ 3227 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3228 } 3229 3230 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3231 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3232 const struct sctp_association *asoc, 3233 const sctp_subtype_t type, void *arg, 3234 sctp_cmd_seq_t *commands) 3235 { 3236 struct sctp_chunk *chunk = arg; 3237 struct sctp_chunk *asconf_ack = NULL; 3238 sctp_addiphdr_t *hdr; 3239 __u32 serial; 3240 3241 if (!sctp_vtag_verify(chunk, asoc)) { 3242 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3243 SCTP_NULL()); 3244 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3245 } 3246 3247 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3248 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3249 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3250 commands); 3251 3252 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3253 serial = ntohl(hdr->serial); 3254 3255 /* ADDIP 4.2 C1) Compare the value of the serial number to the value 3256 * the endpoint stored in a new association variable 3257 * 'Peer-Serial-Number'. 3258 */ 3259 if (serial == asoc->peer.addip_serial + 1) { 3260 /* ADDIP 4.2 C2) If the value found in the serial number is 3261 * equal to the ('Peer-Serial-Number' + 1), the endpoint MUST 3262 * do V1-V5. 3263 */ 3264 asconf_ack = sctp_process_asconf((struct sctp_association *) 3265 asoc, chunk); 3266 if (!asconf_ack) 3267 return SCTP_DISPOSITION_NOMEM; 3268 } else if (serial == asoc->peer.addip_serial) { 3269 /* ADDIP 4.2 C3) If the value found in the serial number is 3270 * equal to the value stored in the 'Peer-Serial-Number' 3271 * IMPLEMENTATION NOTE: As an optimization a receiver may wish 3272 * to save the last ASCONF-ACK for some predetermined period of 3273 * time and instead of re-processing the ASCONF (with the same 3274 * serial number) it may just re-transmit the ASCONF-ACK. 3275 */ 3276 if (asoc->addip_last_asconf_ack) 3277 asconf_ack = asoc->addip_last_asconf_ack; 3278 else 3279 return SCTP_DISPOSITION_DISCARD; 3280 } else { 3281 /* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since 3282 * it must be either a stale packet or from an attacker. 3283 */ 3284 return SCTP_DISPOSITION_DISCARD; 3285 } 3286 3287 /* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent 3288 * back to the source address contained in the IP header of the ASCONF 3289 * being responded to. 3290 */ 3291 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3292 3293 return SCTP_DISPOSITION_CONSUME; 3294 } 3295 3296 /* 3297 * ADDIP Section 4.3 General rules for address manipulation 3298 * When building TLV parameters for the ASCONF Chunk that will add or 3299 * delete IP addresses the D0 to D13 rules should be applied: 3300 */ 3301 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3302 const struct sctp_association *asoc, 3303 const sctp_subtype_t type, void *arg, 3304 sctp_cmd_seq_t *commands) 3305 { 3306 struct sctp_chunk *asconf_ack = arg; 3307 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3308 struct sctp_chunk *abort; 3309 sctp_addiphdr_t *addip_hdr; 3310 __u32 sent_serial, rcvd_serial; 3311 3312 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3313 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3314 SCTP_NULL()); 3315 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3316 } 3317 3318 /* Make sure that the ADDIP chunk has a valid length. */ 3319 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3320 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3321 commands); 3322 3323 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3324 rcvd_serial = ntohl(addip_hdr->serial); 3325 3326 if (last_asconf) { 3327 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3328 sent_serial = ntohl(addip_hdr->serial); 3329 } else { 3330 sent_serial = asoc->addip_serial - 1; 3331 } 3332 3333 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3334 * equal to the next serial number to be used but no ASCONF chunk is 3335 * outstanding the endpoint MUST ABORT the association. Note that a 3336 * sequence number is greater than if it is no more than 2^^31-1 3337 * larger than the current sequence number (using serial arithmetic). 3338 */ 3339 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3340 !(asoc->addip_last_asconf)) { 3341 abort = sctp_make_abort(asoc, asconf_ack, 3342 sizeof(sctp_errhdr_t)); 3343 if (abort) { 3344 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, NULL, 0); 3345 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3346 SCTP_CHUNK(abort)); 3347 } 3348 /* We are going to ABORT, so we might as well stop 3349 * processing the rest of the chunks in the packet. 3350 */ 3351 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3352 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3353 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3354 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3355 SCTP_ERROR(ECONNABORTED)); 3356 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3357 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3358 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3359 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3360 return SCTP_DISPOSITION_ABORT; 3361 } 3362 3363 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3364 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3365 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3366 3367 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3368 asconf_ack)) 3369 return SCTP_DISPOSITION_CONSUME; 3370 3371 abort = sctp_make_abort(asoc, asconf_ack, 3372 sizeof(sctp_errhdr_t)); 3373 if (abort) { 3374 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, NULL, 0); 3375 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3376 SCTP_CHUNK(abort)); 3377 } 3378 /* We are going to ABORT, so we might as well stop 3379 * processing the rest of the chunks in the packet. 3380 */ 3381 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3382 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3383 SCTP_ERROR(ECONNABORTED)); 3384 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3385 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3386 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3387 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3388 return SCTP_DISPOSITION_ABORT; 3389 } 3390 3391 return SCTP_DISPOSITION_DISCARD; 3392 } 3393 3394 /* 3395 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3396 * 3397 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3398 * its cumulative TSN point to the value carried in the FORWARD TSN 3399 * chunk, and then MUST further advance its cumulative TSN point locally 3400 * if possible. 3401 * After the above processing, the data receiver MUST stop reporting any 3402 * missing TSNs earlier than or equal to the new cumulative TSN point. 3403 * 3404 * Verification Tag: 8.5 Verification Tag [Normal verification] 3405 * 3406 * The return value is the disposition of the chunk. 3407 */ 3408 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3409 const struct sctp_association *asoc, 3410 const sctp_subtype_t type, 3411 void *arg, 3412 sctp_cmd_seq_t *commands) 3413 { 3414 struct sctp_chunk *chunk = arg; 3415 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3416 __u16 len; 3417 __u32 tsn; 3418 3419 if (!sctp_vtag_verify(chunk, asoc)) { 3420 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3421 SCTP_NULL()); 3422 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3423 } 3424 3425 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3426 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3427 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3428 commands); 3429 3430 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3431 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3432 len = ntohs(chunk->chunk_hdr->length); 3433 len -= sizeof(struct sctp_chunkhdr); 3434 skb_pull(chunk->skb, len); 3435 3436 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3437 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3438 3439 /* The TSN is too high--silently discard the chunk and count on it 3440 * getting retransmitted later. 3441 */ 3442 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3443 goto discard_noforce; 3444 3445 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3446 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3447 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3448 SCTP_CHUNK(chunk)); 3449 3450 /* Count this as receiving DATA. */ 3451 if (asoc->autoclose) { 3452 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3453 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3454 } 3455 3456 /* FIXME: For now send a SACK, but DATA processing may 3457 * send another. 3458 */ 3459 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3460 3461 return SCTP_DISPOSITION_CONSUME; 3462 3463 discard_noforce: 3464 return SCTP_DISPOSITION_DISCARD; 3465 } 3466 3467 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3468 const struct sctp_endpoint *ep, 3469 const struct sctp_association *asoc, 3470 const sctp_subtype_t type, 3471 void *arg, 3472 sctp_cmd_seq_t *commands) 3473 { 3474 struct sctp_chunk *chunk = arg; 3475 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3476 __u16 len; 3477 __u32 tsn; 3478 3479 if (!sctp_vtag_verify(chunk, asoc)) { 3480 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3481 SCTP_NULL()); 3482 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3483 } 3484 3485 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3486 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3487 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3488 commands); 3489 3490 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3491 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3492 len = ntohs(chunk->chunk_hdr->length); 3493 len -= sizeof(struct sctp_chunkhdr); 3494 skb_pull(chunk->skb, len); 3495 3496 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3497 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3498 3499 /* The TSN is too high--silently discard the chunk and count on it 3500 * getting retransmitted later. 3501 */ 3502 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3503 goto gen_shutdown; 3504 3505 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3506 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3507 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3508 SCTP_CHUNK(chunk)); 3509 3510 /* Go a head and force a SACK, since we are shutting down. */ 3511 gen_shutdown: 3512 /* Implementor's Guide. 3513 * 3514 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3515 * respond to each received packet containing one or more DATA chunk(s) 3516 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3517 */ 3518 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3519 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3520 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3521 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3522 3523 return SCTP_DISPOSITION_CONSUME; 3524 } 3525 3526 /* 3527 * Process an unknown chunk. 3528 * 3529 * Section: 3.2. Also, 2.1 in the implementor's guide. 3530 * 3531 * Chunk Types are encoded such that the highest-order two bits specify 3532 * the action that must be taken if the processing endpoint does not 3533 * recognize the Chunk Type. 3534 * 3535 * 00 - Stop processing this SCTP packet and discard it, do not process 3536 * any further chunks within it. 3537 * 3538 * 01 - Stop processing this SCTP packet and discard it, do not process 3539 * any further chunks within it, and report the unrecognized 3540 * chunk in an 'Unrecognized Chunk Type'. 3541 * 3542 * 10 - Skip this chunk and continue processing. 3543 * 3544 * 11 - Skip this chunk and continue processing, but report in an ERROR 3545 * Chunk using the 'Unrecognized Chunk Type' cause of error. 3546 * 3547 * The return value is the disposition of the chunk. 3548 */ 3549 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 3550 const struct sctp_association *asoc, 3551 const sctp_subtype_t type, 3552 void *arg, 3553 sctp_cmd_seq_t *commands) 3554 { 3555 struct sctp_chunk *unk_chunk = arg; 3556 struct sctp_chunk *err_chunk; 3557 sctp_chunkhdr_t *hdr; 3558 3559 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 3560 3561 if (!sctp_vtag_verify(unk_chunk, asoc)) 3562 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3563 3564 /* Make sure that the chunk has a valid length. 3565 * Since we don't know the chunk type, we use a general 3566 * chunkhdr structure to make a comparison. 3567 */ 3568 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 3569 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3570 commands); 3571 3572 switch (type.chunk & SCTP_CID_ACTION_MASK) { 3573 case SCTP_CID_ACTION_DISCARD: 3574 /* Discard the packet. */ 3575 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3576 break; 3577 case SCTP_CID_ACTION_DISCARD_ERR: 3578 /* Discard the packet. */ 3579 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3580 3581 /* Generate an ERROR chunk as response. */ 3582 hdr = unk_chunk->chunk_hdr; 3583 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3584 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3585 WORD_ROUND(ntohs(hdr->length))); 3586 if (err_chunk) { 3587 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3588 SCTP_CHUNK(err_chunk)); 3589 } 3590 return SCTP_DISPOSITION_CONSUME; 3591 break; 3592 case SCTP_CID_ACTION_SKIP: 3593 /* Skip the chunk. */ 3594 return SCTP_DISPOSITION_DISCARD; 3595 break; 3596 case SCTP_CID_ACTION_SKIP_ERR: 3597 /* Generate an ERROR chunk as response. */ 3598 hdr = unk_chunk->chunk_hdr; 3599 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3600 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3601 WORD_ROUND(ntohs(hdr->length))); 3602 if (err_chunk) { 3603 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3604 SCTP_CHUNK(err_chunk)); 3605 } 3606 /* Skip the chunk. */ 3607 return SCTP_DISPOSITION_CONSUME; 3608 break; 3609 default: 3610 break; 3611 } 3612 3613 return SCTP_DISPOSITION_DISCARD; 3614 } 3615 3616 /* 3617 * Discard the chunk. 3618 * 3619 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 3620 * [Too numerous to mention...] 3621 * Verification Tag: No verification needed. 3622 * Inputs 3623 * (endpoint, asoc, chunk) 3624 * 3625 * Outputs 3626 * (asoc, reply_msg, msg_up, timers, counters) 3627 * 3628 * The return value is the disposition of the chunk. 3629 */ 3630 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 3631 const struct sctp_association *asoc, 3632 const sctp_subtype_t type, 3633 void *arg, 3634 sctp_cmd_seq_t *commands) 3635 { 3636 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 3637 return SCTP_DISPOSITION_DISCARD; 3638 } 3639 3640 /* 3641 * Discard the whole packet. 3642 * 3643 * Section: 8.4 2) 3644 * 3645 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 3646 * silently discard the OOTB packet and take no further action. 3647 * 3648 * Verification Tag: No verification necessary 3649 * 3650 * Inputs 3651 * (endpoint, asoc, chunk) 3652 * 3653 * Outputs 3654 * (asoc, reply_msg, msg_up, timers, counters) 3655 * 3656 * The return value is the disposition of the chunk. 3657 */ 3658 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 3659 const struct sctp_association *asoc, 3660 const sctp_subtype_t type, 3661 void *arg, 3662 sctp_cmd_seq_t *commands) 3663 { 3664 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS); 3665 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3666 3667 return SCTP_DISPOSITION_CONSUME; 3668 } 3669 3670 3671 /* 3672 * The other end is violating protocol. 3673 * 3674 * Section: Not specified 3675 * Verification Tag: Not specified 3676 * Inputs 3677 * (endpoint, asoc, chunk) 3678 * 3679 * Outputs 3680 * (asoc, reply_msg, msg_up, timers, counters) 3681 * 3682 * We simply tag the chunk as a violation. The state machine will log 3683 * the violation and continue. 3684 */ 3685 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 3686 const struct sctp_association *asoc, 3687 const sctp_subtype_t type, 3688 void *arg, 3689 sctp_cmd_seq_t *commands) 3690 { 3691 return SCTP_DISPOSITION_VIOLATION; 3692 } 3693 3694 3695 /* 3696 * Handle a protocol violation when the chunk length is invalid. 3697 * "Invalid" length is identified as smaller then the minimal length a 3698 * given chunk can be. For example, a SACK chunk has invalid length 3699 * if it's length is set to be smaller then the size of sctp_sack_chunk_t. 3700 * 3701 * We inform the other end by sending an ABORT with a Protocol Violation 3702 * error code. 3703 * 3704 * Section: Not specified 3705 * Verification Tag: Nothing to do 3706 * Inputs 3707 * (endpoint, asoc, chunk) 3708 * 3709 * Outputs 3710 * (reply_msg, msg_up, counters) 3711 * 3712 * Generate an ABORT chunk and terminate the association. 3713 */ 3714 static sctp_disposition_t sctp_sf_violation_chunklen( 3715 const struct sctp_endpoint *ep, 3716 const struct sctp_association *asoc, 3717 const sctp_subtype_t type, 3718 void *arg, 3719 sctp_cmd_seq_t *commands) 3720 { 3721 struct sctp_chunk *chunk = arg; 3722 struct sctp_chunk *abort = NULL; 3723 char err_str[]="The following chunk had invalid length:"; 3724 3725 /* Make the abort chunk. */ 3726 abort = sctp_make_abort_violation(asoc, chunk, err_str, 3727 sizeof(err_str)); 3728 if (!abort) 3729 goto nomem; 3730 3731 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 3732 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3733 3734 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 3735 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3736 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 3737 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3738 SCTP_ERROR(ECONNREFUSED)); 3739 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 3740 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 3741 } else { 3742 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3743 SCTP_ERROR(ECONNABORTED)); 3744 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3745 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 3746 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3747 } 3748 3749 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3750 3751 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3752 3753 return SCTP_DISPOSITION_ABORT; 3754 3755 nomem: 3756 return SCTP_DISPOSITION_NOMEM; 3757 } 3758 3759 /*************************************************************************** 3760 * These are the state functions for handling primitive (Section 10) events. 3761 ***************************************************************************/ 3762 /* 3763 * sctp_sf_do_prm_asoc 3764 * 3765 * Section: 10.1 ULP-to-SCTP 3766 * B) Associate 3767 * 3768 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 3769 * outbound stream count) 3770 * -> association id [,destination transport addr list] [,outbound stream 3771 * count] 3772 * 3773 * This primitive allows the upper layer to initiate an association to a 3774 * specific peer endpoint. 3775 * 3776 * The peer endpoint shall be specified by one of the transport addresses 3777 * which defines the endpoint (see Section 1.4). If the local SCTP 3778 * instance has not been initialized, the ASSOCIATE is considered an 3779 * error. 3780 * [This is not relevant for the kernel implementation since we do all 3781 * initialization at boot time. It we hadn't initialized we wouldn't 3782 * get anywhere near this code.] 3783 * 3784 * An association id, which is a local handle to the SCTP association, 3785 * will be returned on successful establishment of the association. If 3786 * SCTP is not able to open an SCTP association with the peer endpoint, 3787 * an error is returned. 3788 * [In the kernel implementation, the struct sctp_association needs to 3789 * be created BEFORE causing this primitive to run.] 3790 * 3791 * Other association parameters may be returned, including the 3792 * complete destination transport addresses of the peer as well as the 3793 * outbound stream count of the local endpoint. One of the transport 3794 * address from the returned destination addresses will be selected by 3795 * the local endpoint as default primary path for sending SCTP packets 3796 * to this peer. The returned "destination transport addr list" can 3797 * be used by the ULP to change the default primary path or to force 3798 * sending a packet to a specific transport address. [All of this 3799 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 3800 * function.] 3801 * 3802 * Mandatory attributes: 3803 * 3804 * o local SCTP instance name - obtained from the INITIALIZE operation. 3805 * [This is the argument asoc.] 3806 * o destination transport addr - specified as one of the transport 3807 * addresses of the peer endpoint with which the association is to be 3808 * established. 3809 * [This is asoc->peer.active_path.] 3810 * o outbound stream count - the number of outbound streams the ULP 3811 * would like to open towards this peer endpoint. 3812 * [BUG: This is not currently implemented.] 3813 * Optional attributes: 3814 * 3815 * None. 3816 * 3817 * The return value is a disposition. 3818 */ 3819 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 3820 const struct sctp_association *asoc, 3821 const sctp_subtype_t type, 3822 void *arg, 3823 sctp_cmd_seq_t *commands) 3824 { 3825 struct sctp_chunk *repl; 3826 3827 /* The comment below says that we enter COOKIE-WAIT AFTER 3828 * sending the INIT, but that doesn't actually work in our 3829 * implementation... 3830 */ 3831 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3832 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 3833 3834 /* RFC 2960 5.1 Normal Establishment of an Association 3835 * 3836 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 3837 * must provide its Verification Tag (Tag_A) in the Initiate 3838 * Tag field. Tag_A SHOULD be a random number in the range of 3839 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 3840 */ 3841 3842 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 3843 if (!repl) 3844 goto nomem; 3845 3846 /* Cast away the const modifier, as we want to just 3847 * rerun it through as a sideffect. 3848 */ 3849 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, 3850 SCTP_ASOC((struct sctp_association *) asoc)); 3851 3852 /* Choose transport for INIT. */ 3853 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 3854 SCTP_CHUNK(repl)); 3855 3856 /* After sending the INIT, "A" starts the T1-init timer and 3857 * enters the COOKIE-WAIT state. 3858 */ 3859 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 3860 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 3861 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 3862 return SCTP_DISPOSITION_CONSUME; 3863 3864 nomem: 3865 return SCTP_DISPOSITION_NOMEM; 3866 } 3867 3868 /* 3869 * Process the SEND primitive. 3870 * 3871 * Section: 10.1 ULP-to-SCTP 3872 * E) Send 3873 * 3874 * Format: SEND(association id, buffer address, byte count [,context] 3875 * [,stream id] [,life time] [,destination transport address] 3876 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 3877 * -> result 3878 * 3879 * This is the main method to send user data via SCTP. 3880 * 3881 * Mandatory attributes: 3882 * 3883 * o association id - local handle to the SCTP association 3884 * 3885 * o buffer address - the location where the user message to be 3886 * transmitted is stored; 3887 * 3888 * o byte count - The size of the user data in number of bytes; 3889 * 3890 * Optional attributes: 3891 * 3892 * o context - an optional 32 bit integer that will be carried in the 3893 * sending failure notification to the ULP if the transportation of 3894 * this User Message fails. 3895 * 3896 * o stream id - to indicate which stream to send the data on. If not 3897 * specified, stream 0 will be used. 3898 * 3899 * o life time - specifies the life time of the user data. The user data 3900 * will not be sent by SCTP after the life time expires. This 3901 * parameter can be used to avoid efforts to transmit stale 3902 * user messages. SCTP notifies the ULP if the data cannot be 3903 * initiated to transport (i.e. sent to the destination via SCTP's 3904 * send primitive) within the life time variable. However, the 3905 * user data will be transmitted if SCTP has attempted to transmit a 3906 * chunk before the life time expired. 3907 * 3908 * o destination transport address - specified as one of the destination 3909 * transport addresses of the peer endpoint to which this packet 3910 * should be sent. Whenever possible, SCTP should use this destination 3911 * transport address for sending the packets, instead of the current 3912 * primary path. 3913 * 3914 * o unorder flag - this flag, if present, indicates that the user 3915 * would like the data delivered in an unordered fashion to the peer 3916 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 3917 * message). 3918 * 3919 * o no-bundle flag - instructs SCTP not to bundle this user data with 3920 * other outbound DATA chunks. SCTP MAY still bundle even when 3921 * this flag is present, when faced with network congestion. 3922 * 3923 * o payload protocol-id - A 32 bit unsigned integer that is to be 3924 * passed to the peer indicating the type of payload protocol data 3925 * being transmitted. This value is passed as opaque data by SCTP. 3926 * 3927 * The return value is the disposition. 3928 */ 3929 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 3930 const struct sctp_association *asoc, 3931 const sctp_subtype_t type, 3932 void *arg, 3933 sctp_cmd_seq_t *commands) 3934 { 3935 struct sctp_chunk *chunk = arg; 3936 3937 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 3938 return SCTP_DISPOSITION_CONSUME; 3939 } 3940 3941 /* 3942 * Process the SHUTDOWN primitive. 3943 * 3944 * Section: 10.1: 3945 * C) Shutdown 3946 * 3947 * Format: SHUTDOWN(association id) 3948 * -> result 3949 * 3950 * Gracefully closes an association. Any locally queued user data 3951 * will be delivered to the peer. The association will be terminated only 3952 * after the peer acknowledges all the SCTP packets sent. A success code 3953 * will be returned on successful termination of the association. If 3954 * attempting to terminate the association results in a failure, an error 3955 * code shall be returned. 3956 * 3957 * Mandatory attributes: 3958 * 3959 * o association id - local handle to the SCTP association 3960 * 3961 * Optional attributes: 3962 * 3963 * None. 3964 * 3965 * The return value is the disposition. 3966 */ 3967 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 3968 const struct sctp_endpoint *ep, 3969 const struct sctp_association *asoc, 3970 const sctp_subtype_t type, 3971 void *arg, 3972 sctp_cmd_seq_t *commands) 3973 { 3974 int disposition; 3975 3976 /* From 9.2 Shutdown of an Association 3977 * Upon receipt of the SHUTDOWN primitive from its upper 3978 * layer, the endpoint enters SHUTDOWN-PENDING state and 3979 * remains there until all outstanding data has been 3980 * acknowledged by its peer. The endpoint accepts no new data 3981 * from its upper layer, but retransmits data to the far end 3982 * if necessary to fill gaps. 3983 */ 3984 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3985 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 3986 3987 /* sctpimpguide-05 Section 2.12.2 3988 * The sender of the SHUTDOWN MAY also start an overall guard timer 3989 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 3990 */ 3991 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 3992 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3993 3994 disposition = SCTP_DISPOSITION_CONSUME; 3995 if (sctp_outq_is_empty(&asoc->outqueue)) { 3996 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 3997 arg, commands); 3998 } 3999 return disposition; 4000 } 4001 4002 /* 4003 * Process the ABORT primitive. 4004 * 4005 * Section: 10.1: 4006 * C) Abort 4007 * 4008 * Format: Abort(association id [, cause code]) 4009 * -> result 4010 * 4011 * Ungracefully closes an association. Any locally queued user data 4012 * will be discarded and an ABORT chunk is sent to the peer. A success code 4013 * will be returned on successful abortion of the association. If 4014 * attempting to abort the association results in a failure, an error 4015 * code shall be returned. 4016 * 4017 * Mandatory attributes: 4018 * 4019 * o association id - local handle to the SCTP association 4020 * 4021 * Optional attributes: 4022 * 4023 * o cause code - reason of the abort to be passed to the peer 4024 * 4025 * None. 4026 * 4027 * The return value is the disposition. 4028 */ 4029 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4030 const struct sctp_endpoint *ep, 4031 const struct sctp_association *asoc, 4032 const sctp_subtype_t type, 4033 void *arg, 4034 sctp_cmd_seq_t *commands) 4035 { 4036 /* From 9.1 Abort of an Association 4037 * Upon receipt of the ABORT primitive from its upper 4038 * layer, the endpoint enters CLOSED state and 4039 * discard all outstanding data has been 4040 * acknowledged by its peer. The endpoint accepts no new data 4041 * from its upper layer, but retransmits data to the far end 4042 * if necessary to fill gaps. 4043 */ 4044 struct sctp_chunk *abort = arg; 4045 sctp_disposition_t retval; 4046 4047 retval = SCTP_DISPOSITION_CONSUME; 4048 4049 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4050 4051 /* Even if we can't send the ABORT due to low memory delete the 4052 * TCB. This is a departure from our typical NOMEM handling. 4053 */ 4054 4055 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4056 SCTP_ERROR(ECONNABORTED)); 4057 /* Delete the established association. */ 4058 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4059 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4060 4061 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4062 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4063 4064 return retval; 4065 } 4066 4067 /* We tried an illegal operation on an association which is closed. */ 4068 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4069 const struct sctp_association *asoc, 4070 const sctp_subtype_t type, 4071 void *arg, 4072 sctp_cmd_seq_t *commands) 4073 { 4074 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4075 return SCTP_DISPOSITION_CONSUME; 4076 } 4077 4078 /* We tried an illegal operation on an association which is shutting 4079 * down. 4080 */ 4081 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4082 const struct sctp_association *asoc, 4083 const sctp_subtype_t type, 4084 void *arg, 4085 sctp_cmd_seq_t *commands) 4086 { 4087 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4088 SCTP_ERROR(-ESHUTDOWN)); 4089 return SCTP_DISPOSITION_CONSUME; 4090 } 4091 4092 /* 4093 * sctp_cookie_wait_prm_shutdown 4094 * 4095 * Section: 4 Note: 2 4096 * Verification Tag: 4097 * Inputs 4098 * (endpoint, asoc) 4099 * 4100 * The RFC does not explicitly address this issue, but is the route through the 4101 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4102 * 4103 * Outputs 4104 * (timers) 4105 */ 4106 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4107 const struct sctp_endpoint *ep, 4108 const struct sctp_association *asoc, 4109 const sctp_subtype_t type, 4110 void *arg, 4111 sctp_cmd_seq_t *commands) 4112 { 4113 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4114 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4115 4116 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4117 SCTP_STATE(SCTP_STATE_CLOSED)); 4118 4119 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4120 4121 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4122 4123 return SCTP_DISPOSITION_DELETE_TCB; 4124 } 4125 4126 /* 4127 * sctp_cookie_echoed_prm_shutdown 4128 * 4129 * Section: 4 Note: 2 4130 * Verification Tag: 4131 * Inputs 4132 * (endpoint, asoc) 4133 * 4134 * The RFC does not explcitly address this issue, but is the route through the 4135 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4136 * 4137 * Outputs 4138 * (timers) 4139 */ 4140 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4141 const struct sctp_endpoint *ep, 4142 const struct sctp_association *asoc, 4143 const sctp_subtype_t type, 4144 void *arg, sctp_cmd_seq_t *commands) 4145 { 4146 /* There is a single T1 timer, so we should be able to use 4147 * common function with the COOKIE-WAIT state. 4148 */ 4149 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4150 } 4151 4152 /* 4153 * sctp_sf_cookie_wait_prm_abort 4154 * 4155 * Section: 4 Note: 2 4156 * Verification Tag: 4157 * Inputs 4158 * (endpoint, asoc) 4159 * 4160 * The RFC does not explicitly address this issue, but is the route through the 4161 * state table when someone issues an abort while in COOKIE_WAIT state. 4162 * 4163 * Outputs 4164 * (timers) 4165 */ 4166 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4167 const struct sctp_endpoint *ep, 4168 const struct sctp_association *asoc, 4169 const sctp_subtype_t type, 4170 void *arg, 4171 sctp_cmd_seq_t *commands) 4172 { 4173 struct sctp_chunk *abort = arg; 4174 sctp_disposition_t retval; 4175 4176 /* Stop T1-init timer */ 4177 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4178 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4179 retval = SCTP_DISPOSITION_CONSUME; 4180 4181 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4182 4183 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4184 SCTP_STATE(SCTP_STATE_CLOSED)); 4185 4186 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4187 4188 /* Even if we can't send the ABORT due to low memory delete the 4189 * TCB. This is a departure from our typical NOMEM handling. 4190 */ 4191 4192 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4193 SCTP_ERROR(ECONNREFUSED)); 4194 /* Delete the established association. */ 4195 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4196 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4197 4198 return retval; 4199 } 4200 4201 /* 4202 * sctp_sf_cookie_echoed_prm_abort 4203 * 4204 * Section: 4 Note: 3 4205 * Verification Tag: 4206 * Inputs 4207 * (endpoint, asoc) 4208 * 4209 * The RFC does not explcitly address this issue, but is the route through the 4210 * state table when someone issues an abort while in COOKIE_ECHOED state. 4211 * 4212 * Outputs 4213 * (timers) 4214 */ 4215 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4216 const struct sctp_endpoint *ep, 4217 const struct sctp_association *asoc, 4218 const sctp_subtype_t type, 4219 void *arg, 4220 sctp_cmd_seq_t *commands) 4221 { 4222 /* There is a single T1 timer, so we should be able to use 4223 * common function with the COOKIE-WAIT state. 4224 */ 4225 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4226 } 4227 4228 /* 4229 * sctp_sf_shutdown_pending_prm_abort 4230 * 4231 * Inputs 4232 * (endpoint, asoc) 4233 * 4234 * The RFC does not explicitly address this issue, but is the route through the 4235 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4236 * 4237 * Outputs 4238 * (timers) 4239 */ 4240 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4241 const struct sctp_endpoint *ep, 4242 const struct sctp_association *asoc, 4243 const sctp_subtype_t type, 4244 void *arg, 4245 sctp_cmd_seq_t *commands) 4246 { 4247 /* Stop the T5-shutdown guard timer. */ 4248 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4249 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4250 4251 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4252 } 4253 4254 /* 4255 * sctp_sf_shutdown_sent_prm_abort 4256 * 4257 * Inputs 4258 * (endpoint, asoc) 4259 * 4260 * The RFC does not explicitly address this issue, but is the route through the 4261 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4262 * 4263 * Outputs 4264 * (timers) 4265 */ 4266 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4267 const struct sctp_endpoint *ep, 4268 const struct sctp_association *asoc, 4269 const sctp_subtype_t type, 4270 void *arg, 4271 sctp_cmd_seq_t *commands) 4272 { 4273 /* Stop the T2-shutdown timer. */ 4274 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4275 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4276 4277 /* Stop the T5-shutdown guard timer. */ 4278 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4279 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4280 4281 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4282 } 4283 4284 /* 4285 * sctp_sf_cookie_echoed_prm_abort 4286 * 4287 * Inputs 4288 * (endpoint, asoc) 4289 * 4290 * The RFC does not explcitly address this issue, but is the route through the 4291 * state table when someone issues an abort while in COOKIE_ECHOED state. 4292 * 4293 * Outputs 4294 * (timers) 4295 */ 4296 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4297 const struct sctp_endpoint *ep, 4298 const struct sctp_association *asoc, 4299 const sctp_subtype_t type, 4300 void *arg, 4301 sctp_cmd_seq_t *commands) 4302 { 4303 /* The same T2 timer, so we should be able to use 4304 * common function with the SHUTDOWN-SENT state. 4305 */ 4306 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4307 } 4308 4309 /* 4310 * Process the REQUESTHEARTBEAT primitive 4311 * 4312 * 10.1 ULP-to-SCTP 4313 * J) Request Heartbeat 4314 * 4315 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4316 * 4317 * -> result 4318 * 4319 * Instructs the local endpoint to perform a HeartBeat on the specified 4320 * destination transport address of the given association. The returned 4321 * result should indicate whether the transmission of the HEARTBEAT 4322 * chunk to the destination address is successful. 4323 * 4324 * Mandatory attributes: 4325 * 4326 * o association id - local handle to the SCTP association 4327 * 4328 * o destination transport address - the transport address of the 4329 * association on which a heartbeat should be issued. 4330 */ 4331 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4332 const struct sctp_endpoint *ep, 4333 const struct sctp_association *asoc, 4334 const sctp_subtype_t type, 4335 void *arg, 4336 sctp_cmd_seq_t *commands) 4337 { 4338 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 4339 (struct sctp_transport *)arg, commands)) 4340 return SCTP_DISPOSITION_NOMEM; 4341 4342 /* 4343 * RFC 2960 (bis), section 8.3 4344 * 4345 * D) Request an on-demand HEARTBEAT on a specific destination 4346 * transport address of a given association. 4347 * 4348 * The endpoint should increment the respective error counter of 4349 * the destination transport address each time a HEARTBEAT is sent 4350 * to that address and not acknowledged within one RTO. 4351 * 4352 */ 4353 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 4354 SCTP_TRANSPORT(arg)); 4355 return SCTP_DISPOSITION_CONSUME; 4356 } 4357 4358 /* 4359 * ADDIP Section 4.1 ASCONF Chunk Procedures 4360 * When an endpoint has an ASCONF signaled change to be sent to the 4361 * remote endpoint it should do A1 to A9 4362 */ 4363 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 4364 const struct sctp_association *asoc, 4365 const sctp_subtype_t type, 4366 void *arg, 4367 sctp_cmd_seq_t *commands) 4368 { 4369 struct sctp_chunk *chunk = arg; 4370 4371 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4372 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4373 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4374 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4375 return SCTP_DISPOSITION_CONSUME; 4376 } 4377 4378 /* 4379 * Ignore the primitive event 4380 * 4381 * The return value is the disposition of the primitive. 4382 */ 4383 sctp_disposition_t sctp_sf_ignore_primitive( 4384 const struct sctp_endpoint *ep, 4385 const struct sctp_association *asoc, 4386 const sctp_subtype_t type, 4387 void *arg, 4388 sctp_cmd_seq_t *commands) 4389 { 4390 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 4391 return SCTP_DISPOSITION_DISCARD; 4392 } 4393 4394 /*************************************************************************** 4395 * These are the state functions for the OTHER events. 4396 ***************************************************************************/ 4397 4398 /* 4399 * Start the shutdown negotiation. 4400 * 4401 * From Section 9.2: 4402 * Once all its outstanding data has been acknowledged, the endpoint 4403 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 4404 * TSN Ack field the last sequential TSN it has received from the peer. 4405 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 4406 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 4407 * with the updated last sequential TSN received from its peer. 4408 * 4409 * The return value is the disposition. 4410 */ 4411 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 4412 const struct sctp_endpoint *ep, 4413 const struct sctp_association *asoc, 4414 const sctp_subtype_t type, 4415 void *arg, 4416 sctp_cmd_seq_t *commands) 4417 { 4418 struct sctp_chunk *reply; 4419 4420 /* Once all its outstanding data has been acknowledged, the 4421 * endpoint shall send a SHUTDOWN chunk to its peer including 4422 * in the Cumulative TSN Ack field the last sequential TSN it 4423 * has received from the peer. 4424 */ 4425 reply = sctp_make_shutdown(asoc, NULL); 4426 if (!reply) 4427 goto nomem; 4428 4429 /* Set the transport for the SHUTDOWN chunk and the timeout for the 4430 * T2-shutdown timer. 4431 */ 4432 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4433 4434 /* It shall then start the T2-shutdown timer */ 4435 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4436 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4437 4438 if (asoc->autoclose) 4439 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4440 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4441 4442 /* and enter the SHUTDOWN-SENT state. */ 4443 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4444 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 4445 4446 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4447 * 4448 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4449 * or SHUTDOWN-ACK. 4450 */ 4451 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4452 4453 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4454 4455 return SCTP_DISPOSITION_CONSUME; 4456 4457 nomem: 4458 return SCTP_DISPOSITION_NOMEM; 4459 } 4460 4461 /* 4462 * Generate a SHUTDOWN ACK now that everything is SACK'd. 4463 * 4464 * From Section 9.2: 4465 * 4466 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4467 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 4468 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 4469 * endpoint must re-send the SHUTDOWN ACK. 4470 * 4471 * The return value is the disposition. 4472 */ 4473 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 4474 const struct sctp_endpoint *ep, 4475 const struct sctp_association *asoc, 4476 const sctp_subtype_t type, 4477 void *arg, 4478 sctp_cmd_seq_t *commands) 4479 { 4480 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 4481 struct sctp_chunk *reply; 4482 4483 /* There are 2 ways of getting here: 4484 * 1) called in response to a SHUTDOWN chunk 4485 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 4486 * 4487 * For the case (2), the arg parameter is set to NULL. We need 4488 * to check that we have a chunk before accessing it's fields. 4489 */ 4490 if (chunk) { 4491 if (!sctp_vtag_verify(chunk, asoc)) 4492 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4493 4494 /* Make sure that the SHUTDOWN chunk has a valid length. */ 4495 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 4496 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4497 commands); 4498 } 4499 4500 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4501 * shall send a SHUTDOWN ACK ... 4502 */ 4503 reply = sctp_make_shutdown_ack(asoc, chunk); 4504 if (!reply) 4505 goto nomem; 4506 4507 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 4508 * the T2-shutdown timer. 4509 */ 4510 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4511 4512 /* and start/restart a T2-shutdown timer of its own, */ 4513 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4514 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4515 4516 if (asoc->autoclose) 4517 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4518 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4519 4520 /* Enter the SHUTDOWN-ACK-SENT state. */ 4521 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4522 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 4523 4524 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4525 * 4526 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4527 * or SHUTDOWN-ACK. 4528 */ 4529 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4530 4531 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4532 4533 return SCTP_DISPOSITION_CONSUME; 4534 4535 nomem: 4536 return SCTP_DISPOSITION_NOMEM; 4537 } 4538 4539 /* 4540 * Ignore the event defined as other 4541 * 4542 * The return value is the disposition of the event. 4543 */ 4544 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 4545 const struct sctp_association *asoc, 4546 const sctp_subtype_t type, 4547 void *arg, 4548 sctp_cmd_seq_t *commands) 4549 { 4550 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 4551 return SCTP_DISPOSITION_DISCARD; 4552 } 4553 4554 /************************************************************ 4555 * These are the state functions for handling timeout events. 4556 ************************************************************/ 4557 4558 /* 4559 * RTX Timeout 4560 * 4561 * Section: 6.3.3 Handle T3-rtx Expiration 4562 * 4563 * Whenever the retransmission timer T3-rtx expires for a destination 4564 * address, do the following: 4565 * [See below] 4566 * 4567 * The return value is the disposition of the chunk. 4568 */ 4569 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 4570 const struct sctp_association *asoc, 4571 const sctp_subtype_t type, 4572 void *arg, 4573 sctp_cmd_seq_t *commands) 4574 { 4575 struct sctp_transport *transport = arg; 4576 4577 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS); 4578 4579 if (asoc->overall_error_count >= asoc->max_retrans) { 4580 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4581 SCTP_ERROR(ETIMEDOUT)); 4582 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 4583 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4584 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 4585 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4586 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4587 return SCTP_DISPOSITION_DELETE_TCB; 4588 } 4589 4590 /* E1) For the destination address for which the timer 4591 * expires, adjust its ssthresh with rules defined in Section 4592 * 7.2.3 and set the cwnd <- MTU. 4593 */ 4594 4595 /* E2) For the destination address for which the timer 4596 * expires, set RTO <- RTO * 2 ("back off the timer"). The 4597 * maximum value discussed in rule C7 above (RTO.max) may be 4598 * used to provide an upper bound to this doubling operation. 4599 */ 4600 4601 /* E3) Determine how many of the earliest (i.e., lowest TSN) 4602 * outstanding DATA chunks for the address for which the 4603 * T3-rtx has expired will fit into a single packet, subject 4604 * to the MTU constraint for the path corresponding to the 4605 * destination transport address to which the retransmission 4606 * is being sent (this may be different from the address for 4607 * which the timer expires [see Section 6.4]). Call this 4608 * value K. Bundle and retransmit those K DATA chunks in a 4609 * single packet to the destination endpoint. 4610 * 4611 * Note: Any DATA chunks that were sent to the address for 4612 * which the T3-rtx timer expired but did not fit in one MTU 4613 * (rule E3 above), should be marked for retransmission and 4614 * sent as soon as cwnd allows (normally when a SACK arrives). 4615 */ 4616 4617 /* Do some failure management (Section 8.2). */ 4618 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 4619 4620 /* NB: Rules E4 and F1 are implicit in R1. */ 4621 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 4622 4623 return SCTP_DISPOSITION_CONSUME; 4624 } 4625 4626 /* 4627 * Generate delayed SACK on timeout 4628 * 4629 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 4630 * 4631 * The guidelines on delayed acknowledgement algorithm specified in 4632 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 4633 * acknowledgement SHOULD be generated for at least every second packet 4634 * (not every second DATA chunk) received, and SHOULD be generated 4635 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 4636 * some situations it may be beneficial for an SCTP transmitter to be 4637 * more conservative than the algorithms detailed in this document 4638 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 4639 * the following algorithms allow. 4640 */ 4641 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 4642 const struct sctp_association *asoc, 4643 const sctp_subtype_t type, 4644 void *arg, 4645 sctp_cmd_seq_t *commands) 4646 { 4647 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS); 4648 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4649 return SCTP_DISPOSITION_CONSUME; 4650 } 4651 4652 /* 4653 * sctp_sf_t1_init_timer_expire 4654 * 4655 * Section: 4 Note: 2 4656 * Verification Tag: 4657 * Inputs 4658 * (endpoint, asoc) 4659 * 4660 * RFC 2960 Section 4 Notes 4661 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 4662 * and re-start the T1-init timer without changing state. This MUST 4663 * be repeated up to 'Max.Init.Retransmits' times. After that, the 4664 * endpoint MUST abort the initialization process and report the 4665 * error to SCTP user. 4666 * 4667 * Outputs 4668 * (timers, events) 4669 * 4670 */ 4671 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 4672 const struct sctp_association *asoc, 4673 const sctp_subtype_t type, 4674 void *arg, 4675 sctp_cmd_seq_t *commands) 4676 { 4677 struct sctp_chunk *repl = NULL; 4678 struct sctp_bind_addr *bp; 4679 int attempts = asoc->init_err_counter + 1; 4680 4681 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 4682 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS); 4683 4684 if (attempts <= asoc->max_init_attempts) { 4685 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 4686 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 4687 if (!repl) 4688 return SCTP_DISPOSITION_NOMEM; 4689 4690 /* Choose transport for INIT. */ 4691 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4692 SCTP_CHUNK(repl)); 4693 4694 /* Issue a sideeffect to do the needed accounting. */ 4695 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 4696 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4697 4698 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4699 } else { 4700 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 4701 " max_init_attempts: %d\n", 4702 attempts, asoc->max_init_attempts); 4703 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4704 SCTP_ERROR(ETIMEDOUT)); 4705 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4706 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 4707 return SCTP_DISPOSITION_DELETE_TCB; 4708 } 4709 4710 return SCTP_DISPOSITION_CONSUME; 4711 } 4712 4713 /* 4714 * sctp_sf_t1_cookie_timer_expire 4715 * 4716 * Section: 4 Note: 2 4717 * Verification Tag: 4718 * Inputs 4719 * (endpoint, asoc) 4720 * 4721 * RFC 2960 Section 4 Notes 4722 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 4723 * COOKIE ECHO and re-start the T1-cookie timer without changing 4724 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 4725 * After that, the endpoint MUST abort the initialization process and 4726 * report the error to SCTP user. 4727 * 4728 * Outputs 4729 * (timers, events) 4730 * 4731 */ 4732 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 4733 const struct sctp_association *asoc, 4734 const sctp_subtype_t type, 4735 void *arg, 4736 sctp_cmd_seq_t *commands) 4737 { 4738 struct sctp_chunk *repl = NULL; 4739 int attempts = asoc->init_err_counter + 1; 4740 4741 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 4742 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS); 4743 4744 if (attempts <= asoc->max_init_attempts) { 4745 repl = sctp_make_cookie_echo(asoc, NULL); 4746 if (!repl) 4747 return SCTP_DISPOSITION_NOMEM; 4748 4749 /* Issue a sideeffect to do the needed accounting. */ 4750 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 4751 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 4752 4753 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4754 } else { 4755 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4756 SCTP_ERROR(ETIMEDOUT)); 4757 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4758 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 4759 return SCTP_DISPOSITION_DELETE_TCB; 4760 } 4761 4762 return SCTP_DISPOSITION_CONSUME; 4763 } 4764 4765 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 4766 * with the updated last sequential TSN received from its peer. 4767 * 4768 * An endpoint should limit the number of retransmissions of the 4769 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 4770 * If this threshold is exceeded the endpoint should destroy the TCB and 4771 * MUST report the peer endpoint unreachable to the upper layer (and 4772 * thus the association enters the CLOSED state). The reception of any 4773 * packet from its peer (i.e. as the peer sends all of its queued DATA 4774 * chunks) should clear the endpoint's retransmission count and restart 4775 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 4776 * all of its queued DATA chunks that have not yet been sent. 4777 */ 4778 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 4779 const struct sctp_association *asoc, 4780 const sctp_subtype_t type, 4781 void *arg, 4782 sctp_cmd_seq_t *commands) 4783 { 4784 struct sctp_chunk *reply = NULL; 4785 4786 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 4787 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 4788 4789 if (asoc->overall_error_count >= asoc->max_retrans) { 4790 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4791 SCTP_ERROR(ETIMEDOUT)); 4792 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 4793 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4794 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 4795 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4796 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4797 return SCTP_DISPOSITION_DELETE_TCB; 4798 } 4799 4800 switch (asoc->state) { 4801 case SCTP_STATE_SHUTDOWN_SENT: 4802 reply = sctp_make_shutdown(asoc, NULL); 4803 break; 4804 4805 case SCTP_STATE_SHUTDOWN_ACK_SENT: 4806 reply = sctp_make_shutdown_ack(asoc, NULL); 4807 break; 4808 4809 default: 4810 BUG(); 4811 break; 4812 } 4813 4814 if (!reply) 4815 goto nomem; 4816 4817 /* Do some failure management (Section 8.2). */ 4818 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 4819 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 4820 4821 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 4822 * the T2-shutdown timer. 4823 */ 4824 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4825 4826 /* Restart the T2-shutdown timer. */ 4827 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4828 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4829 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4830 return SCTP_DISPOSITION_CONSUME; 4831 4832 nomem: 4833 return SCTP_DISPOSITION_NOMEM; 4834 } 4835 4836 /* 4837 * ADDIP Section 4.1 ASCONF CHunk Procedures 4838 * If the T4 RTO timer expires the endpoint should do B1 to B5 4839 */ 4840 sctp_disposition_t sctp_sf_t4_timer_expire( 4841 const struct sctp_endpoint *ep, 4842 const struct sctp_association *asoc, 4843 const sctp_subtype_t type, 4844 void *arg, 4845 sctp_cmd_seq_t *commands) 4846 { 4847 struct sctp_chunk *chunk = asoc->addip_last_asconf; 4848 struct sctp_transport *transport = chunk->transport; 4849 4850 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS); 4851 4852 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 4853 * detection on the appropriate destination address as defined in 4854 * RFC2960 [5] section 8.1 and 8.2. 4855 */ 4856 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 4857 4858 /* Reconfig T4 timer and transport. */ 4859 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4860 4861 /* ADDIP 4.1 B2) Increment the association error counters and perform 4862 * endpoint failure detection on the association as defined in 4863 * RFC2960 [5] section 8.1 and 8.2. 4864 * association error counter is incremented in SCTP_CMD_STRIKE. 4865 */ 4866 if (asoc->overall_error_count >= asoc->max_retrans) { 4867 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4868 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4869 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4870 SCTP_ERROR(ETIMEDOUT)); 4871 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4872 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 4873 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4874 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 4875 return SCTP_DISPOSITION_ABORT; 4876 } 4877 4878 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 4879 * the ASCONF chunk was sent by doubling the RTO timer value. 4880 * This is done in SCTP_CMD_STRIKE. 4881 */ 4882 4883 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 4884 * choose an alternate destination address (please refer to RFC2960 4885 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 4886 * chunk, it MUST be the same (including its serial number) as the last 4887 * ASCONF sent. 4888 */ 4889 sctp_chunk_hold(asoc->addip_last_asconf); 4890 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4891 SCTP_CHUNK(asoc->addip_last_asconf)); 4892 4893 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 4894 * destination is selected, then the RTO used will be that of the new 4895 * destination address. 4896 */ 4897 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4898 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4899 4900 return SCTP_DISPOSITION_CONSUME; 4901 } 4902 4903 /* sctpimpguide-05 Section 2.12.2 4904 * The sender of the SHUTDOWN MAY also start an overall guard timer 4905 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4906 * At the expiration of this timer the sender SHOULD abort the association 4907 * by sending an ABORT chunk. 4908 */ 4909 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 4910 const struct sctp_association *asoc, 4911 const sctp_subtype_t type, 4912 void *arg, 4913 sctp_cmd_seq_t *commands) 4914 { 4915 struct sctp_chunk *reply = NULL; 4916 4917 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 4918 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 4919 4920 reply = sctp_make_abort(asoc, NULL, 0); 4921 if (!reply) 4922 goto nomem; 4923 4924 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4925 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4926 SCTP_ERROR(ETIMEDOUT)); 4927 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4928 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 4929 4930 return SCTP_DISPOSITION_DELETE_TCB; 4931 nomem: 4932 return SCTP_DISPOSITION_NOMEM; 4933 } 4934 4935 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 4936 * the association is automatically closed by starting the shutdown process. 4937 * The work that needs to be done is same as when SHUTDOWN is initiated by 4938 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 4939 */ 4940 sctp_disposition_t sctp_sf_autoclose_timer_expire( 4941 const struct sctp_endpoint *ep, 4942 const struct sctp_association *asoc, 4943 const sctp_subtype_t type, 4944 void *arg, 4945 sctp_cmd_seq_t *commands) 4946 { 4947 int disposition; 4948 4949 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS); 4950 4951 /* From 9.2 Shutdown of an Association 4952 * Upon receipt of the SHUTDOWN primitive from its upper 4953 * layer, the endpoint enters SHUTDOWN-PENDING state and 4954 * remains there until all outstanding data has been 4955 * acknowledged by its peer. The endpoint accepts no new data 4956 * from its upper layer, but retransmits data to the far end 4957 * if necessary to fill gaps. 4958 */ 4959 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4960 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4961 4962 /* sctpimpguide-05 Section 2.12.2 4963 * The sender of the SHUTDOWN MAY also start an overall guard timer 4964 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4965 */ 4966 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4967 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4968 disposition = SCTP_DISPOSITION_CONSUME; 4969 if (sctp_outq_is_empty(&asoc->outqueue)) { 4970 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4971 arg, commands); 4972 } 4973 return disposition; 4974 } 4975 4976 /***************************************************************************** 4977 * These are sa state functions which could apply to all types of events. 4978 ****************************************************************************/ 4979 4980 /* 4981 * This table entry is not implemented. 4982 * 4983 * Inputs 4984 * (endpoint, asoc, chunk) 4985 * 4986 * The return value is the disposition of the chunk. 4987 */ 4988 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 4989 const struct sctp_association *asoc, 4990 const sctp_subtype_t type, 4991 void *arg, 4992 sctp_cmd_seq_t *commands) 4993 { 4994 return SCTP_DISPOSITION_NOT_IMPL; 4995 } 4996 4997 /* 4998 * This table entry represents a bug. 4999 * 5000 * Inputs 5001 * (endpoint, asoc, chunk) 5002 * 5003 * The return value is the disposition of the chunk. 5004 */ 5005 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 5006 const struct sctp_association *asoc, 5007 const sctp_subtype_t type, 5008 void *arg, 5009 sctp_cmd_seq_t *commands) 5010 { 5011 return SCTP_DISPOSITION_BUG; 5012 } 5013 5014 /* 5015 * This table entry represents the firing of a timer in the wrong state. 5016 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5017 * when the association is in the wrong state. This event should 5018 * be ignored, so as to prevent any rearming of the timer. 5019 * 5020 * Inputs 5021 * (endpoint, asoc, chunk) 5022 * 5023 * The return value is the disposition of the chunk. 5024 */ 5025 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 5026 const struct sctp_association *asoc, 5027 const sctp_subtype_t type, 5028 void *arg, 5029 sctp_cmd_seq_t *commands) 5030 { 5031 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5032 return SCTP_DISPOSITION_CONSUME; 5033 } 5034 5035 /******************************************************************** 5036 * 2nd Level Abstractions 5037 ********************************************************************/ 5038 5039 /* Pull the SACK chunk based on the SACK header. */ 5040 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5041 { 5042 struct sctp_sackhdr *sack; 5043 unsigned int len; 5044 __u16 num_blocks; 5045 __u16 num_dup_tsns; 5046 5047 /* Protect ourselves from reading too far into 5048 * the skb from a bogus sender. 5049 */ 5050 sack = (struct sctp_sackhdr *) chunk->skb->data; 5051 5052 num_blocks = ntohs(sack->num_gap_ack_blocks); 5053 num_dup_tsns = ntohs(sack->num_dup_tsns); 5054 len = sizeof(struct sctp_sackhdr); 5055 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5056 if (len > chunk->skb->len) 5057 return NULL; 5058 5059 skb_pull(chunk->skb, len); 5060 5061 return sack; 5062 } 5063 5064 /* Create an ABORT packet to be sent as a response, with the specified 5065 * error causes. 5066 */ 5067 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5068 const struct sctp_association *asoc, 5069 struct sctp_chunk *chunk, 5070 const void *payload, 5071 size_t paylen) 5072 { 5073 struct sctp_packet *packet; 5074 struct sctp_chunk *abort; 5075 5076 packet = sctp_ootb_pkt_new(asoc, chunk); 5077 5078 if (packet) { 5079 /* Make an ABORT. 5080 * The T bit will be set if the asoc is NULL. 5081 */ 5082 abort = sctp_make_abort(asoc, chunk, paylen); 5083 if (!abort) { 5084 sctp_ootb_pkt_free(packet); 5085 return NULL; 5086 } 5087 5088 /* Reflect vtag if T-Bit is set */ 5089 if (sctp_test_T_bit(abort)) 5090 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5091 5092 /* Add specified error causes, i.e., payload, to the 5093 * end of the chunk. 5094 */ 5095 sctp_addto_chunk(abort, paylen, payload); 5096 5097 /* Set the skb to the belonging sock for accounting. */ 5098 abort->skb->sk = ep->base.sk; 5099 5100 sctp_packet_append_chunk(packet, abort); 5101 5102 } 5103 5104 return packet; 5105 } 5106 5107 /* Allocate a packet for responding in the OOTB conditions. */ 5108 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5109 const struct sctp_chunk *chunk) 5110 { 5111 struct sctp_packet *packet; 5112 struct sctp_transport *transport; 5113 __u16 sport; 5114 __u16 dport; 5115 __u32 vtag; 5116 5117 /* Get the source and destination port from the inbound packet. */ 5118 sport = ntohs(chunk->sctp_hdr->dest); 5119 dport = ntohs(chunk->sctp_hdr->source); 5120 5121 /* The V-tag is going to be the same as the inbound packet if no 5122 * association exists, otherwise, use the peer's vtag. 5123 */ 5124 if (asoc) { 5125 vtag = asoc->peer.i.init_tag; 5126 } else { 5127 /* Special case the INIT and stale COOKIE_ECHO as there is no 5128 * vtag yet. 5129 */ 5130 switch(chunk->chunk_hdr->type) { 5131 case SCTP_CID_INIT: 5132 { 5133 sctp_init_chunk_t *init; 5134 5135 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5136 vtag = ntohl(init->init_hdr.init_tag); 5137 break; 5138 } 5139 default: 5140 vtag = ntohl(chunk->sctp_hdr->vtag); 5141 break; 5142 } 5143 } 5144 5145 /* Make a transport for the bucket, Eliza... */ 5146 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5147 if (!transport) 5148 goto nomem; 5149 5150 /* Cache a route for the transport with the chunk's destination as 5151 * the source address. 5152 */ 5153 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5154 sctp_sk(sctp_get_ctl_sock())); 5155 5156 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5157 packet = sctp_packet_config(packet, vtag, 0); 5158 5159 return packet; 5160 5161 nomem: 5162 return NULL; 5163 } 5164 5165 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5166 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5167 { 5168 sctp_transport_free(packet->transport); 5169 } 5170 5171 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5172 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5173 const struct sctp_association *asoc, 5174 const struct sctp_chunk *chunk, 5175 sctp_cmd_seq_t *commands, 5176 struct sctp_chunk *err_chunk) 5177 { 5178 struct sctp_packet *packet; 5179 5180 if (err_chunk) { 5181 packet = sctp_ootb_pkt_new(asoc, chunk); 5182 if (packet) { 5183 struct sctp_signed_cookie *cookie; 5184 5185 /* Override the OOTB vtag from the cookie. */ 5186 cookie = chunk->subh.cookie_hdr; 5187 packet->vtag = cookie->c.peer_vtag; 5188 5189 /* Set the skb to the belonging sock for accounting. */ 5190 err_chunk->skb->sk = ep->base.sk; 5191 sctp_packet_append_chunk(packet, err_chunk); 5192 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5193 SCTP_PACKET(packet)); 5194 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5195 } else 5196 sctp_chunk_free (err_chunk); 5197 } 5198 } 5199 5200 5201 /* Process a data chunk */ 5202 static int sctp_eat_data(const struct sctp_association *asoc, 5203 struct sctp_chunk *chunk, 5204 sctp_cmd_seq_t *commands) 5205 { 5206 sctp_datahdr_t *data_hdr; 5207 struct sctp_chunk *err; 5208 size_t datalen; 5209 sctp_verb_t deliver; 5210 int tmp; 5211 __u32 tsn; 5212 int account_value; 5213 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 5214 struct sock *sk = asoc->base.sk; 5215 int rcvbuf_over = 0; 5216 5217 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5218 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5219 5220 tsn = ntohl(data_hdr->tsn); 5221 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5222 5223 /* ASSERT: Now skb->data is really the user data. */ 5224 5225 /* 5226 * If we are established, and we have used up our receive buffer 5227 * memory, think about droping the frame. 5228 * Note that we have an opportunity to improve performance here. 5229 * If we accept one chunk from an skbuff, we have to keep all the 5230 * memory of that skbuff around until the chunk is read into user 5231 * space. Therefore, once we accept 1 chunk we may as well accept all 5232 * remaining chunks in the skbuff. The data_accepted flag helps us do 5233 * that. 5234 */ 5235 if ((asoc->state == SCTP_STATE_ESTABLISHED) && (!chunk->data_accepted)) { 5236 /* 5237 * If the receive buffer policy is 1, then each 5238 * association can allocate up to sk_rcvbuf bytes 5239 * otherwise, all the associations in aggregate 5240 * may allocate up to sk_rcvbuf bytes 5241 */ 5242 if (asoc->ep->rcvbuf_policy) 5243 account_value = atomic_read(&asoc->rmem_alloc); 5244 else 5245 account_value = atomic_read(&sk->sk_rmem_alloc); 5246 if (account_value > sk->sk_rcvbuf) { 5247 /* 5248 * We need to make forward progress, even when we are 5249 * under memory pressure, so we always allow the 5250 * next tsn after the ctsn ack point to be accepted. 5251 * This lets us avoid deadlocks in which we have to 5252 * drop frames that would otherwise let us drain the 5253 * receive queue. 5254 */ 5255 if ((sctp_tsnmap_get_ctsn(map) + 1) != tsn) 5256 return SCTP_IERROR_IGNORE_TSN; 5257 5258 /* 5259 * We're going to accept the frame but we should renege 5260 * to make space for it. This will send us down that 5261 * path later in this function. 5262 */ 5263 rcvbuf_over = 1; 5264 } 5265 } 5266 5267 /* Process ECN based congestion. 5268 * 5269 * Since the chunk structure is reused for all chunks within 5270 * a packet, we use ecn_ce_done to track if we've already 5271 * done CE processing for this packet. 5272 * 5273 * We need to do ECN processing even if we plan to discard the 5274 * chunk later. 5275 */ 5276 5277 if (!chunk->ecn_ce_done) { 5278 struct sctp_af *af; 5279 chunk->ecn_ce_done = 1; 5280 5281 af = sctp_get_af_specific( 5282 ipver2af(ip_hdr(chunk->skb)->version)); 5283 5284 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5285 /* Do real work as sideffect. */ 5286 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5287 SCTP_U32(tsn)); 5288 } 5289 } 5290 5291 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5292 if (tmp < 0) { 5293 /* The TSN is too high--silently discard the chunk and 5294 * count on it getting retransmitted later. 5295 */ 5296 return SCTP_IERROR_HIGH_TSN; 5297 } else if (tmp > 0) { 5298 /* This is a duplicate. Record it. */ 5299 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5300 return SCTP_IERROR_DUP_TSN; 5301 } 5302 5303 /* This is a new TSN. */ 5304 5305 /* Discard if there is no room in the receive window. 5306 * Actually, allow a little bit of overflow (up to a MTU). 5307 */ 5308 datalen = ntohs(chunk->chunk_hdr->length); 5309 datalen -= sizeof(sctp_data_chunk_t); 5310 5311 deliver = SCTP_CMD_CHUNK_ULP; 5312 5313 /* Think about partial delivery. */ 5314 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5315 5316 /* Even if we don't accept this chunk there is 5317 * memory pressure. 5318 */ 5319 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5320 } 5321 5322 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5323 * seems a bit troublesome in that frag_point varies based on 5324 * PMTU. In cases, such as loopback, this might be a rather 5325 * large spill over. 5326 * NOTE: If we have a full receive buffer here, we only renege if 5327 * our receiver can still make progress without the tsn being 5328 * received. We do this because in the event that the associations 5329 * receive queue is empty we are filling a leading gap, and since 5330 * reneging moves the gap to the end of the tsn stream, we are likely 5331 * to stall again very shortly. Avoiding the renege when we fill a 5332 * leading gap is a good heuristic for avoiding such steady state 5333 * stalls. 5334 */ 5335 if (!asoc->rwnd || asoc->rwnd_over || 5336 (datalen > asoc->rwnd + asoc->frag_point) || 5337 (rcvbuf_over && (!skb_queue_len(&sk->sk_receive_queue)))) { 5338 5339 /* If this is the next TSN, consider reneging to make 5340 * room. Note: Playing nice with a confused sender. A 5341 * malicious sender can still eat up all our buffer 5342 * space and in the future we may want to detect and 5343 * do more drastic reneging. 5344 */ 5345 if (sctp_tsnmap_has_gap(map) && 5346 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5347 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5348 deliver = SCTP_CMD_RENEGE; 5349 } else { 5350 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5351 "rwnd: %d\n", tsn, datalen, 5352 asoc->rwnd); 5353 return SCTP_IERROR_IGNORE_TSN; 5354 } 5355 } 5356 5357 /* 5358 * Section 3.3.10.9 No User Data (9) 5359 * 5360 * Cause of error 5361 * --------------- 5362 * No User Data: This error cause is returned to the originator of a 5363 * DATA chunk if a received DATA chunk has no user data. 5364 */ 5365 if (unlikely(0 == datalen)) { 5366 err = sctp_make_abort_no_data(asoc, chunk, tsn); 5367 if (err) { 5368 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5369 SCTP_CHUNK(err)); 5370 } 5371 /* We are going to ABORT, so we might as well stop 5372 * processing the rest of the chunks in the packet. 5373 */ 5374 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 5375 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5376 SCTP_ERROR(ECONNABORTED)); 5377 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5378 SCTP_PERR(SCTP_ERROR_NO_DATA)); 5379 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5380 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5381 return SCTP_IERROR_NO_DATA; 5382 } 5383 5384 /* If definately accepting the DATA chunk, record its TSN, otherwise 5385 * wait for renege processing. 5386 */ 5387 if (SCTP_CMD_CHUNK_ULP == deliver) 5388 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 5389 5390 chunk->data_accepted = 1; 5391 5392 /* Note: Some chunks may get overcounted (if we drop) or overcounted 5393 * if we renege and the chunk arrives again. 5394 */ 5395 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 5396 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 5397 else 5398 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 5399 5400 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 5401 * 5402 * If an endpoint receive a DATA chunk with an invalid stream 5403 * identifier, it shall acknowledge the reception of the DATA chunk 5404 * following the normal procedure, immediately send an ERROR chunk 5405 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 5406 * and discard the DATA chunk. 5407 */ 5408 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { 5409 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 5410 &data_hdr->stream, 5411 sizeof(data_hdr->stream)); 5412 if (err) 5413 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5414 SCTP_CHUNK(err)); 5415 return SCTP_IERROR_BAD_STREAM; 5416 } 5417 5418 /* Send the data up to the user. Note: Schedule the 5419 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 5420 * chunk needs the updated rwnd. 5421 */ 5422 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 5423 5424 return SCTP_IERROR_NO_ERROR; 5425 } 5426