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 __u16 error, 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, GFP_ATOMIC); 190 if (!ev) 191 goto nomem; 192 193 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 194 195 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 196 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 197 * not the chunk should be discarded. If the endpoint is in 198 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 199 * T2-shutdown timer and remove all knowledge of the 200 * association (and thus the association enters the CLOSED 201 * state). 202 */ 203 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 204 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 205 206 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 207 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 208 209 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 210 SCTP_STATE(SCTP_STATE_CLOSED)); 211 212 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 213 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 214 215 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 216 217 return SCTP_DISPOSITION_DELETE_TCB; 218 219 nomem: 220 return SCTP_DISPOSITION_NOMEM; 221 } 222 223 /* 224 * Respond to a normal INIT chunk. 225 * We are the side that is being asked for an association. 226 * 227 * Section: 5.1 Normal Establishment of an Association, B 228 * B) "Z" shall respond immediately with an INIT ACK chunk. The 229 * destination IP address of the INIT ACK MUST be set to the source 230 * IP address of the INIT to which this INIT ACK is responding. In 231 * the response, besides filling in other parameters, "Z" must set the 232 * Verification Tag field to Tag_A, and also provide its own 233 * Verification Tag (Tag_Z) in the Initiate Tag field. 234 * 235 * Verification Tag: Must be 0. 236 * 237 * Inputs 238 * (endpoint, asoc, chunk) 239 * 240 * Outputs 241 * (asoc, reply_msg, msg_up, timers, counters) 242 * 243 * The return value is the disposition of the chunk. 244 */ 245 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 246 const struct sctp_association *asoc, 247 const sctp_subtype_t type, 248 void *arg, 249 sctp_cmd_seq_t *commands) 250 { 251 struct sctp_chunk *chunk = arg; 252 struct sctp_chunk *repl; 253 struct sctp_association *new_asoc; 254 struct sctp_chunk *err_chunk; 255 struct sctp_packet *packet; 256 sctp_unrecognized_param_t *unk_param; 257 struct sock *sk; 258 int len; 259 260 /* 6.10 Bundling 261 * An endpoint MUST NOT bundle INIT, INIT ACK or 262 * SHUTDOWN COMPLETE with any other chunks. 263 * 264 * IG Section 2.11.2 265 * Furthermore, we require that the receiver of an INIT chunk MUST 266 * enforce these rules by silently discarding an arriving packet 267 * with an INIT chunk that is bundled with other chunks. 268 */ 269 if (!chunk->singleton) 270 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 271 272 /* If the packet is an OOTB packet which is temporarily on the 273 * control endpoint, respond with an ABORT. 274 */ 275 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 276 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 277 278 sk = ep->base.sk; 279 /* If the endpoint is not listening or if the number of associations 280 * on the TCP-style socket exceed the max backlog, respond with an 281 * ABORT. 282 */ 283 if (!sctp_sstate(sk, LISTENING) || 284 (sctp_style(sk, TCP) && 285 sk_acceptq_is_full(sk))) 286 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 287 288 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 289 * Tag. 290 */ 291 if (chunk->sctp_hdr->vtag != 0) 292 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 293 294 /* Make sure that the INIT chunk has a valid length. 295 * Normally, this would cause an ABORT with a Protocol Violation 296 * error, but since we don't have an association, we'll 297 * just discard the packet. 298 */ 299 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 300 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 301 302 /* Verify the INIT chunk before processing it. */ 303 err_chunk = NULL; 304 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 305 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 306 &err_chunk)) { 307 /* This chunk contains fatal error. It is to be discarded. 308 * Send an ABORT, with causes if there is any. 309 */ 310 if (err_chunk) { 311 packet = sctp_abort_pkt_new(ep, asoc, arg, 312 (__u8 *)(err_chunk->chunk_hdr) + 313 sizeof(sctp_chunkhdr_t), 314 ntohs(err_chunk->chunk_hdr->length) - 315 sizeof(sctp_chunkhdr_t)); 316 317 sctp_chunk_free(err_chunk); 318 319 if (packet) { 320 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 321 SCTP_PACKET(packet)); 322 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 323 return SCTP_DISPOSITION_CONSUME; 324 } else { 325 return SCTP_DISPOSITION_NOMEM; 326 } 327 } else { 328 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 329 commands); 330 } 331 } 332 333 /* Grab the INIT header. */ 334 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 335 336 /* Tag the variable length parameters. */ 337 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 338 339 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 340 if (!new_asoc) 341 goto nomem; 342 343 /* The call, sctp_process_init(), can fail on memory allocation. */ 344 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 345 sctp_source(chunk), 346 (sctp_init_chunk_t *)chunk->chunk_hdr, 347 GFP_ATOMIC)) 348 goto nomem_init; 349 350 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 351 352 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 353 354 /* If there are errors need to be reported for unknown parameters, 355 * make sure to reserve enough room in the INIT ACK for them. 356 */ 357 len = 0; 358 if (err_chunk) 359 len = ntohs(err_chunk->chunk_hdr->length) - 360 sizeof(sctp_chunkhdr_t); 361 362 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 363 goto nomem_ack; 364 365 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 366 if (!repl) 367 goto nomem_ack; 368 369 /* If there are errors need to be reported for unknown parameters, 370 * include them in the outgoing INIT ACK as "Unrecognized parameter" 371 * parameter. 372 */ 373 if (err_chunk) { 374 /* Get the "Unrecognized parameter" parameter(s) out of the 375 * ERROR chunk generated by sctp_verify_init(). Since the 376 * error cause code for "unknown parameter" and the 377 * "Unrecognized parameter" type is the same, we can 378 * construct the parameters in INIT ACK by copying the 379 * ERROR causes over. 380 */ 381 unk_param = (sctp_unrecognized_param_t *) 382 ((__u8 *)(err_chunk->chunk_hdr) + 383 sizeof(sctp_chunkhdr_t)); 384 /* Replace the cause code with the "Unrecognized parameter" 385 * parameter type. 386 */ 387 sctp_addto_chunk(repl, len, unk_param); 388 sctp_chunk_free(err_chunk); 389 } 390 391 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 392 393 /* 394 * Note: After sending out INIT ACK with the State Cookie parameter, 395 * "Z" MUST NOT allocate any resources, nor keep any states for the 396 * new association. Otherwise, "Z" will be vulnerable to resource 397 * attacks. 398 */ 399 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 400 401 return SCTP_DISPOSITION_DELETE_TCB; 402 403 nomem_ack: 404 if (err_chunk) 405 sctp_chunk_free(err_chunk); 406 nomem_init: 407 sctp_association_free(new_asoc); 408 nomem: 409 return SCTP_DISPOSITION_NOMEM; 410 } 411 412 /* 413 * Respond to a normal INIT ACK chunk. 414 * We are the side that is initiating the association. 415 * 416 * Section: 5.1 Normal Establishment of an Association, C 417 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 418 * timer and leave COOKIE-WAIT state. "A" shall then send the State 419 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 420 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 421 * 422 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 423 * DATA chunks, but it MUST be the first chunk in the packet and 424 * until the COOKIE ACK is returned the sender MUST NOT send any 425 * other packets to the peer. 426 * 427 * Verification Tag: 3.3.3 428 * If the value of the Initiate Tag in a received INIT ACK chunk is 429 * found to be 0, the receiver MUST treat it as an error and close the 430 * association by transmitting an ABORT. 431 * 432 * Inputs 433 * (endpoint, asoc, chunk) 434 * 435 * Outputs 436 * (asoc, reply_msg, msg_up, timers, counters) 437 * 438 * The return value is the disposition of the chunk. 439 */ 440 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, 441 const struct sctp_association *asoc, 442 const sctp_subtype_t type, 443 void *arg, 444 sctp_cmd_seq_t *commands) 445 { 446 struct sctp_chunk *chunk = arg; 447 sctp_init_chunk_t *initchunk; 448 __u32 init_tag; 449 struct sctp_chunk *err_chunk; 450 struct sctp_packet *packet; 451 sctp_disposition_t ret; 452 453 if (!sctp_vtag_verify(chunk, asoc)) 454 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 455 456 /* Make sure that the INIT-ACK chunk has a valid length */ 457 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 458 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 459 commands); 460 /* 6.10 Bundling 461 * An endpoint MUST NOT bundle INIT, INIT ACK or 462 * SHUTDOWN COMPLETE with any other chunks. 463 */ 464 if (!chunk->singleton) 465 return SCTP_DISPOSITION_VIOLATION; 466 467 /* Grab the INIT header. */ 468 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 469 470 init_tag = ntohl(chunk->subh.init_hdr->init_tag); 471 472 /* Verification Tag: 3.3.3 473 * If the value of the Initiate Tag in a received INIT ACK 474 * chunk is found to be 0, the receiver MUST treat it as an 475 * error and close the association by transmitting an ABORT. 476 */ 477 if (!init_tag) { 478 struct sctp_chunk *reply = sctp_make_abort(asoc, chunk, 0); 479 if (!reply) 480 goto nomem; 481 482 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 483 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 484 SCTP_STATE(SCTP_STATE_CLOSED)); 485 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 486 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 487 return SCTP_DISPOSITION_DELETE_TCB; 488 } 489 490 /* Verify the INIT chunk before processing it. */ 491 err_chunk = NULL; 492 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 493 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 494 &err_chunk)) { 495 496 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 497 498 /* This chunk contains fatal error. It is to be discarded. 499 * Send an ABORT, with causes if there is any. 500 */ 501 if (err_chunk) { 502 packet = sctp_abort_pkt_new(ep, asoc, arg, 503 (__u8 *)(err_chunk->chunk_hdr) + 504 sizeof(sctp_chunkhdr_t), 505 ntohs(err_chunk->chunk_hdr->length) - 506 sizeof(sctp_chunkhdr_t)); 507 508 sctp_chunk_free(err_chunk); 509 510 if (packet) { 511 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 512 SCTP_PACKET(packet)); 513 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 514 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 515 SCTP_STATE(SCTP_STATE_CLOSED)); 516 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, 517 SCTP_NULL()); 518 return SCTP_DISPOSITION_CONSUME; 519 } else { 520 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 521 SCTP_STATE(SCTP_STATE_CLOSED)); 522 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, 523 SCTP_NULL()); 524 return SCTP_DISPOSITION_NOMEM; 525 } 526 } else { 527 ret = sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 528 commands); 529 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 530 SCTP_STATE(SCTP_STATE_CLOSED)); 531 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, 532 SCTP_NULL()); 533 return ret; 534 } 535 } 536 537 /* Tag the variable length parameters. Note that we never 538 * convert the parameters in an INIT chunk. 539 */ 540 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 541 542 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 543 544 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 545 SCTP_PEER_INIT(initchunk)); 546 547 /* Reset init error count upon receipt of INIT-ACK. */ 548 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 549 550 /* 5.1 C) "A" shall stop the T1-init timer and leave 551 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 552 * timer, and enter the COOKIE-ECHOED state. 553 */ 554 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 555 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 556 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 557 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 558 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 559 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 560 561 /* 5.1 C) "A" shall then send the State Cookie received in the 562 * INIT ACK chunk in a COOKIE ECHO chunk, ... 563 */ 564 /* If there is any errors to report, send the ERROR chunk generated 565 * for unknown parameters as well. 566 */ 567 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 568 SCTP_CHUNK(err_chunk)); 569 570 return SCTP_DISPOSITION_CONSUME; 571 572 nomem: 573 return SCTP_DISPOSITION_NOMEM; 574 } 575 576 /* 577 * Respond to a normal COOKIE ECHO chunk. 578 * We are the side that is being asked for an association. 579 * 580 * Section: 5.1 Normal Establishment of an Association, D 581 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 582 * with a COOKIE ACK chunk after building a TCB and moving to 583 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 584 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 585 * chunk MUST be the first chunk in the packet. 586 * 587 * IMPLEMENTATION NOTE: An implementation may choose to send the 588 * Communication Up notification to the SCTP user upon reception 589 * of a valid COOKIE ECHO chunk. 590 * 591 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 592 * D) Rules for packet carrying a COOKIE ECHO 593 * 594 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 595 * Initial Tag received in the INIT ACK. 596 * 597 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 598 * 599 * Inputs 600 * (endpoint, asoc, chunk) 601 * 602 * Outputs 603 * (asoc, reply_msg, msg_up, timers, counters) 604 * 605 * The return value is the disposition of the chunk. 606 */ 607 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, 608 const struct sctp_association *asoc, 609 const sctp_subtype_t type, void *arg, 610 sctp_cmd_seq_t *commands) 611 { 612 struct sctp_chunk *chunk = arg; 613 struct sctp_association *new_asoc; 614 sctp_init_chunk_t *peer_init; 615 struct sctp_chunk *repl; 616 struct sctp_ulpevent *ev; 617 int error = 0; 618 struct sctp_chunk *err_chk_p; 619 620 /* If the packet is an OOTB packet which is temporarily on the 621 * control endpoint, respond with an ABORT. 622 */ 623 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 624 return sctp_sf_ootb(ep, asoc, type, arg, commands); 625 626 /* Make sure that the COOKIE_ECHO chunk has a valid length. 627 * In this case, we check that we have enough for at least a 628 * chunk header. More detailed verification is done 629 * in sctp_unpack_cookie(). 630 */ 631 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 632 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 633 634 /* "Decode" the chunk. We have no optional parameters so we 635 * are in good shape. 636 */ 637 chunk->subh.cookie_hdr = 638 (struct sctp_signed_cookie *)chunk->skb->data; 639 skb_pull(chunk->skb, 640 ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); 641 642 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 643 * "Z" will reply with a COOKIE ACK chunk after building a TCB 644 * and moving to the ESTABLISHED state. 645 */ 646 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 647 &err_chk_p); 648 649 /* FIXME: 650 * If the re-build failed, what is the proper error path 651 * from here? 652 * 653 * [We should abort the association. --piggy] 654 */ 655 if (!new_asoc) { 656 /* FIXME: Several errors are possible. A bad cookie should 657 * be silently discarded, but think about logging it too. 658 */ 659 switch (error) { 660 case -SCTP_IERROR_NOMEM: 661 goto nomem; 662 663 case -SCTP_IERROR_STALE_COOKIE: 664 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 665 err_chk_p); 666 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 667 668 case -SCTP_IERROR_BAD_SIG: 669 default: 670 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 671 }; 672 } 673 674 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 675 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 676 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 677 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 678 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 679 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 680 681 if (new_asoc->autoclose) 682 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 683 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 684 685 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 686 687 /* Re-build the bind address for the association is done in 688 * the sctp_unpack_cookie() already. 689 */ 690 /* This is a brand-new association, so these are not yet side 691 * effects--it is safe to run them here. 692 */ 693 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 694 695 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 696 &chunk->subh.cookie_hdr->c.peer_addr, 697 peer_init, GFP_ATOMIC)) 698 goto nomem_init; 699 700 repl = sctp_make_cookie_ack(new_asoc, chunk); 701 if (!repl) 702 goto nomem_repl; 703 704 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 705 706 /* RFC 2960 5.1 Normal Establishment of an Association 707 * 708 * D) IMPLEMENTATION NOTE: An implementation may choose to 709 * send the Communication Up notification to the SCTP user 710 * upon reception of a valid COOKIE ECHO chunk. 711 */ 712 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 713 new_asoc->c.sinit_num_ostreams, 714 new_asoc->c.sinit_max_instreams, 715 GFP_ATOMIC); 716 if (!ev) 717 goto nomem_ev; 718 719 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 720 721 /* Sockets API Draft Section 5.3.1.6 722 * When a peer sends a Adaption Layer Indication parameter , SCTP 723 * delivers this notification to inform the application that of the 724 * peers requested adaption layer. 725 */ 726 if (new_asoc->peer.adaption_ind) { 727 ev = sctp_ulpevent_make_adaption_indication(new_asoc, 728 GFP_ATOMIC); 729 if (!ev) 730 goto nomem_ev; 731 732 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 733 SCTP_ULPEVENT(ev)); 734 } 735 736 return SCTP_DISPOSITION_CONSUME; 737 738 nomem_ev: 739 sctp_chunk_free(repl); 740 nomem_repl: 741 nomem_init: 742 sctp_association_free(new_asoc); 743 nomem: 744 return SCTP_DISPOSITION_NOMEM; 745 } 746 747 /* 748 * Respond to a normal COOKIE ACK chunk. 749 * We are the side that is being asked for an association. 750 * 751 * RFC 2960 5.1 Normal Establishment of an Association 752 * 753 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 754 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 755 * timer. It may also notify its ULP about the successful 756 * establishment of the association with a Communication Up 757 * notification (see Section 10). 758 * 759 * Verification Tag: 760 * Inputs 761 * (endpoint, asoc, chunk) 762 * 763 * Outputs 764 * (asoc, reply_msg, msg_up, timers, counters) 765 * 766 * The return value is the disposition of the chunk. 767 */ 768 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, 769 const struct sctp_association *asoc, 770 const sctp_subtype_t type, void *arg, 771 sctp_cmd_seq_t *commands) 772 { 773 struct sctp_chunk *chunk = arg; 774 struct sctp_ulpevent *ev; 775 776 if (!sctp_vtag_verify(chunk, asoc)) 777 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 778 779 /* Verify that the chunk length for the COOKIE-ACK is OK. 780 * If we don't do this, any bundled chunks may be junked. 781 */ 782 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 783 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 784 commands); 785 786 /* Reset init error count upon receipt of COOKIE-ACK, 787 * to avoid problems with the managemement of this 788 * counter in stale cookie situations when a transition back 789 * from the COOKIE-ECHOED state to the COOKIE-WAIT 790 * state is performed. 791 */ 792 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 793 794 /* RFC 2960 5.1 Normal Establishment of an Association 795 * 796 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 797 * from the COOKIE-ECHOED state to the ESTABLISHED state, 798 * stopping the T1-cookie timer. 799 */ 800 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 801 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 802 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 803 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 804 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 805 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); 806 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 807 if (asoc->autoclose) 808 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 809 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 810 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 811 812 /* It may also notify its ULP about the successful 813 * establishment of the association with a Communication Up 814 * notification (see Section 10). 815 */ 816 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 817 0, asoc->c.sinit_num_ostreams, 818 asoc->c.sinit_max_instreams, 819 GFP_ATOMIC); 820 821 if (!ev) 822 goto nomem; 823 824 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 825 826 /* Sockets API Draft Section 5.3.1.6 827 * When a peer sends a Adaption Layer Indication parameter , SCTP 828 * delivers this notification to inform the application that of the 829 * peers requested adaption layer. 830 */ 831 if (asoc->peer.adaption_ind) { 832 ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC); 833 if (!ev) 834 goto nomem; 835 836 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 837 SCTP_ULPEVENT(ev)); 838 } 839 840 return SCTP_DISPOSITION_CONSUME; 841 nomem: 842 return SCTP_DISPOSITION_NOMEM; 843 } 844 845 /* Generate and sendout a heartbeat packet. */ 846 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 847 const struct sctp_association *asoc, 848 const sctp_subtype_t type, 849 void *arg, 850 sctp_cmd_seq_t *commands) 851 { 852 struct sctp_transport *transport = (struct sctp_transport *) arg; 853 struct sctp_chunk *reply; 854 sctp_sender_hb_info_t hbinfo; 855 size_t paylen = 0; 856 857 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; 858 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); 859 hbinfo.daddr = transport->ipaddr; 860 hbinfo.sent_at = jiffies; 861 862 /* Send a heartbeat to our peer. */ 863 paylen = sizeof(sctp_sender_hb_info_t); 864 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); 865 if (!reply) 866 return SCTP_DISPOSITION_NOMEM; 867 868 /* Set rto_pending indicating that an RTT measurement 869 * is started with this heartbeat chunk. 870 */ 871 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 872 SCTP_TRANSPORT(transport)); 873 874 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 875 return SCTP_DISPOSITION_CONSUME; 876 } 877 878 /* Generate a HEARTBEAT packet on the given transport. */ 879 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 880 const struct sctp_association *asoc, 881 const sctp_subtype_t type, 882 void *arg, 883 sctp_cmd_seq_t *commands) 884 { 885 struct sctp_transport *transport = (struct sctp_transport *) arg; 886 887 if (asoc->overall_error_count > asoc->max_retrans) { 888 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 889 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 890 SCTP_U32(SCTP_ERROR_NO_ERROR)); 891 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 892 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 893 return SCTP_DISPOSITION_DELETE_TCB; 894 } 895 896 /* Section 3.3.5. 897 * The Sender-specific Heartbeat Info field should normally include 898 * information about the sender's current time when this HEARTBEAT 899 * chunk is sent and the destination transport address to which this 900 * HEARTBEAT is sent (see Section 8.3). 901 */ 902 903 if (transport->hb_allowed) { 904 if (SCTP_DISPOSITION_NOMEM == 905 sctp_sf_heartbeat(ep, asoc, type, arg, 906 commands)) 907 return SCTP_DISPOSITION_NOMEM; 908 /* Set transport error counter and association error counter 909 * when sending heartbeat. 910 */ 911 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 912 SCTP_TRANSPORT(transport)); 913 } 914 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 915 SCTP_TRANSPORT(transport)); 916 917 return SCTP_DISPOSITION_CONSUME; 918 } 919 920 /* 921 * Process an heartbeat request. 922 * 923 * Section: 8.3 Path Heartbeat 924 * The receiver of the HEARTBEAT should immediately respond with a 925 * HEARTBEAT ACK that contains the Heartbeat Information field copied 926 * from the received HEARTBEAT chunk. 927 * 928 * Verification Tag: 8.5 Verification Tag [Normal verification] 929 * When receiving an SCTP packet, the endpoint MUST ensure that the 930 * value in the Verification Tag field of the received SCTP packet 931 * matches its own Tag. If the received Verification Tag value does not 932 * match the receiver's own tag value, the receiver shall silently 933 * discard the packet and shall not process it any further except for 934 * those cases listed in Section 8.5.1 below. 935 * 936 * Inputs 937 * (endpoint, asoc, chunk) 938 * 939 * Outputs 940 * (asoc, reply_msg, msg_up, timers, counters) 941 * 942 * The return value is the disposition of the chunk. 943 */ 944 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 945 const struct sctp_association *asoc, 946 const sctp_subtype_t type, 947 void *arg, 948 sctp_cmd_seq_t *commands) 949 { 950 struct sctp_chunk *chunk = arg; 951 struct sctp_chunk *reply; 952 size_t paylen = 0; 953 954 if (!sctp_vtag_verify(chunk, asoc)) 955 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 956 957 /* Make sure that the HEARTBEAT chunk has a valid length. */ 958 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 959 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 960 commands); 961 962 /* 8.3 The receiver of the HEARTBEAT should immediately 963 * respond with a HEARTBEAT ACK that contains the Heartbeat 964 * Information field copied from the received HEARTBEAT chunk. 965 */ 966 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 967 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 968 skb_pull(chunk->skb, paylen); 969 970 reply = sctp_make_heartbeat_ack(asoc, chunk, 971 chunk->subh.hb_hdr, paylen); 972 if (!reply) 973 goto nomem; 974 975 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 976 return SCTP_DISPOSITION_CONSUME; 977 978 nomem: 979 return SCTP_DISPOSITION_NOMEM; 980 } 981 982 /* 983 * Process the returning HEARTBEAT ACK. 984 * 985 * Section: 8.3 Path Heartbeat 986 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 987 * should clear the error counter of the destination transport 988 * address to which the HEARTBEAT was sent, and mark the destination 989 * transport address as active if it is not so marked. The endpoint may 990 * optionally report to the upper layer when an inactive destination 991 * address is marked as active due to the reception of the latest 992 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 993 * clear the association overall error count as well (as defined 994 * in section 8.1). 995 * 996 * The receiver of the HEARTBEAT ACK should also perform an RTT 997 * measurement for that destination transport address using the time 998 * value carried in the HEARTBEAT ACK chunk. 999 * 1000 * Verification Tag: 8.5 Verification Tag [Normal verification] 1001 * 1002 * Inputs 1003 * (endpoint, asoc, chunk) 1004 * 1005 * Outputs 1006 * (asoc, reply_msg, msg_up, timers, counters) 1007 * 1008 * The return value is the disposition of the chunk. 1009 */ 1010 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 1011 const struct sctp_association *asoc, 1012 const sctp_subtype_t type, 1013 void *arg, 1014 sctp_cmd_seq_t *commands) 1015 { 1016 struct sctp_chunk *chunk = arg; 1017 union sctp_addr from_addr; 1018 struct sctp_transport *link; 1019 sctp_sender_hb_info_t *hbinfo; 1020 unsigned long max_interval; 1021 1022 if (!sctp_vtag_verify(chunk, asoc)) 1023 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1024 1025 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1026 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1027 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1028 commands); 1029 1030 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1031 from_addr = hbinfo->daddr; 1032 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1033 1034 /* This should never happen, but lets log it if so. */ 1035 if (unlikely(!link)) { 1036 if (from_addr.sa.sa_family == AF_INET6) { 1037 printk(KERN_WARNING 1038 "%s association %p could not find address " 1039 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n", 1040 __FUNCTION__, 1041 asoc, 1042 NIP6(from_addr.v6.sin6_addr)); 1043 } else { 1044 printk(KERN_WARNING 1045 "%s association %p could not find address " 1046 "%u.%u.%u.%u\n", 1047 __FUNCTION__, 1048 asoc, 1049 NIPQUAD(from_addr.v4.sin_addr.s_addr)); 1050 } 1051 return SCTP_DISPOSITION_DISCARD; 1052 } 1053 1054 max_interval = link->hb_interval + link->rto; 1055 1056 /* Check if the timestamp looks valid. */ 1057 if (time_after(hbinfo->sent_at, jiffies) || 1058 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1059 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp" 1060 "received for transport: %p\n", 1061 __FUNCTION__, link); 1062 return SCTP_DISPOSITION_DISCARD; 1063 } 1064 1065 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1066 * the HEARTBEAT should clear the error counter of the 1067 * destination transport address to which the HEARTBEAT was 1068 * sent and mark the destination transport address as active if 1069 * it is not so marked. 1070 */ 1071 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1072 1073 return SCTP_DISPOSITION_CONSUME; 1074 } 1075 1076 /* Helper function to send out an abort for the restart 1077 * condition. 1078 */ 1079 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1080 struct sctp_chunk *init, 1081 sctp_cmd_seq_t *commands) 1082 { 1083 int len; 1084 struct sctp_packet *pkt; 1085 union sctp_addr_param *addrparm; 1086 struct sctp_errhdr *errhdr; 1087 struct sctp_endpoint *ep; 1088 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1089 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1090 1091 /* Build the error on the stack. We are way to malloc crazy 1092 * throughout the code today. 1093 */ 1094 errhdr = (struct sctp_errhdr *)buffer; 1095 addrparm = (union sctp_addr_param *)errhdr->variable; 1096 1097 /* Copy into a parm format. */ 1098 len = af->to_addr_param(ssa, addrparm); 1099 len += sizeof(sctp_errhdr_t); 1100 1101 errhdr->cause = SCTP_ERROR_RESTART; 1102 errhdr->length = htons(len); 1103 1104 /* Assign to the control socket. */ 1105 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1106 1107 /* Association is NULL since this may be a restart attack and we 1108 * want to send back the attacker's vtag. 1109 */ 1110 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1111 1112 if (!pkt) 1113 goto out; 1114 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1115 1116 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1117 1118 /* Discard the rest of the inbound packet. */ 1119 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1120 1121 out: 1122 /* Even if there is no memory, treat as a failure so 1123 * the packet will get dropped. 1124 */ 1125 return 0; 1126 } 1127 1128 /* A restart is occurring, check to make sure no new addresses 1129 * are being added as we may be under a takeover attack. 1130 */ 1131 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1132 const struct sctp_association *asoc, 1133 struct sctp_chunk *init, 1134 sctp_cmd_seq_t *commands) 1135 { 1136 struct sctp_transport *new_addr, *addr; 1137 struct list_head *pos, *pos2; 1138 int found; 1139 1140 /* Implementor's Guide - Sectin 5.2.2 1141 * ... 1142 * Before responding the endpoint MUST check to see if the 1143 * unexpected INIT adds new addresses to the association. If new 1144 * addresses are added to the association, the endpoint MUST respond 1145 * with an ABORT.. 1146 */ 1147 1148 /* Search through all current addresses and make sure 1149 * we aren't adding any new ones. 1150 */ 1151 new_addr = NULL; 1152 found = 0; 1153 1154 list_for_each(pos, &new_asoc->peer.transport_addr_list) { 1155 new_addr = list_entry(pos, struct sctp_transport, transports); 1156 found = 0; 1157 list_for_each(pos2, &asoc->peer.transport_addr_list) { 1158 addr = list_entry(pos2, struct sctp_transport, 1159 transports); 1160 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1161 &addr->ipaddr)) { 1162 found = 1; 1163 break; 1164 } 1165 } 1166 if (!found) 1167 break; 1168 } 1169 1170 /* If a new address was added, ABORT the sender. */ 1171 if (!found && new_addr) { 1172 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1173 } 1174 1175 /* Return success if all addresses were found. */ 1176 return found; 1177 } 1178 1179 /* Populate the verification/tie tags based on overlapping INIT 1180 * scenario. 1181 * 1182 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1183 */ 1184 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1185 const struct sctp_association *asoc) 1186 { 1187 switch (asoc->state) { 1188 1189 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1190 1191 case SCTP_STATE_COOKIE_WAIT: 1192 new_asoc->c.my_vtag = asoc->c.my_vtag; 1193 new_asoc->c.my_ttag = asoc->c.my_vtag; 1194 new_asoc->c.peer_ttag = 0; 1195 break; 1196 1197 case SCTP_STATE_COOKIE_ECHOED: 1198 new_asoc->c.my_vtag = asoc->c.my_vtag; 1199 new_asoc->c.my_ttag = asoc->c.my_vtag; 1200 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1201 break; 1202 1203 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1204 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1205 */ 1206 default: 1207 new_asoc->c.my_ttag = asoc->c.my_vtag; 1208 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1209 break; 1210 }; 1211 1212 /* Other parameters for the endpoint SHOULD be copied from the 1213 * existing parameters of the association (e.g. number of 1214 * outbound streams) into the INIT ACK and cookie. 1215 */ 1216 new_asoc->rwnd = asoc->rwnd; 1217 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1218 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1219 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1220 } 1221 1222 /* 1223 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1224 * handling action. 1225 * 1226 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1227 * 1228 * Returns value representing action to be taken. These action values 1229 * correspond to Action/Description values in RFC 2960, Table 2. 1230 */ 1231 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1232 const struct sctp_association *asoc) 1233 { 1234 /* In this case, the peer may have restarted. */ 1235 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1236 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1237 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1238 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1239 return 'A'; 1240 1241 /* Collision case B. */ 1242 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1243 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1244 (0 == asoc->c.peer_vtag))) { 1245 return 'B'; 1246 } 1247 1248 /* Collision case D. */ 1249 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1250 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1251 return 'D'; 1252 1253 /* Collision case C. */ 1254 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1255 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1256 (0 == new_asoc->c.my_ttag) && 1257 (0 == new_asoc->c.peer_ttag)) 1258 return 'C'; 1259 1260 /* No match to any of the special cases; discard this packet. */ 1261 return 'E'; 1262 } 1263 1264 /* Common helper routine for both duplicate and simulataneous INIT 1265 * chunk handling. 1266 */ 1267 static sctp_disposition_t sctp_sf_do_unexpected_init( 1268 const struct sctp_endpoint *ep, 1269 const struct sctp_association *asoc, 1270 const sctp_subtype_t type, 1271 void *arg, sctp_cmd_seq_t *commands) 1272 { 1273 sctp_disposition_t retval; 1274 struct sctp_chunk *chunk = arg; 1275 struct sctp_chunk *repl; 1276 struct sctp_association *new_asoc; 1277 struct sctp_chunk *err_chunk; 1278 struct sctp_packet *packet; 1279 sctp_unrecognized_param_t *unk_param; 1280 int len; 1281 1282 /* 6.10 Bundling 1283 * An endpoint MUST NOT bundle INIT, INIT ACK or 1284 * SHUTDOWN COMPLETE with any other chunks. 1285 * 1286 * IG Section 2.11.2 1287 * Furthermore, we require that the receiver of an INIT chunk MUST 1288 * enforce these rules by silently discarding an arriving packet 1289 * with an INIT chunk that is bundled with other chunks. 1290 */ 1291 if (!chunk->singleton) 1292 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1293 1294 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1295 * Tag. 1296 */ 1297 if (chunk->sctp_hdr->vtag != 0) 1298 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1299 1300 /* Make sure that the INIT chunk has a valid length. 1301 * In this case, we generate a protocol violation since we have 1302 * an association established. 1303 */ 1304 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1305 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1306 commands); 1307 /* Grab the INIT header. */ 1308 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1309 1310 /* Tag the variable length parameters. */ 1311 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1312 1313 /* Verify the INIT chunk before processing it. */ 1314 err_chunk = NULL; 1315 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1316 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1317 &err_chunk)) { 1318 /* This chunk contains fatal error. It is to be discarded. 1319 * Send an ABORT, with causes if there is any. 1320 */ 1321 if (err_chunk) { 1322 packet = sctp_abort_pkt_new(ep, asoc, arg, 1323 (__u8 *)(err_chunk->chunk_hdr) + 1324 sizeof(sctp_chunkhdr_t), 1325 ntohs(err_chunk->chunk_hdr->length) - 1326 sizeof(sctp_chunkhdr_t)); 1327 1328 if (packet) { 1329 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1330 SCTP_PACKET(packet)); 1331 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1332 retval = SCTP_DISPOSITION_CONSUME; 1333 } else { 1334 retval = SCTP_DISPOSITION_NOMEM; 1335 } 1336 goto cleanup; 1337 } else { 1338 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1339 commands); 1340 } 1341 } 1342 1343 /* 1344 * Other parameters for the endpoint SHOULD be copied from the 1345 * existing parameters of the association (e.g. number of 1346 * outbound streams) into the INIT ACK and cookie. 1347 * FIXME: We are copying parameters from the endpoint not the 1348 * association. 1349 */ 1350 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1351 if (!new_asoc) 1352 goto nomem; 1353 1354 /* In the outbound INIT ACK the endpoint MUST copy its current 1355 * Verification Tag and Peers Verification tag into a reserved 1356 * place (local tie-tag and per tie-tag) within the state cookie. 1357 */ 1358 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1359 sctp_source(chunk), 1360 (sctp_init_chunk_t *)chunk->chunk_hdr, 1361 GFP_ATOMIC)) { 1362 retval = SCTP_DISPOSITION_NOMEM; 1363 goto nomem_init; 1364 } 1365 1366 /* Make sure no new addresses are being added during the 1367 * restart. Do not do this check for COOKIE-WAIT state, 1368 * since there are no peer addresses to check against. 1369 * Upon return an ABORT will have been sent if needed. 1370 */ 1371 if (!sctp_state(asoc, COOKIE_WAIT)) { 1372 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1373 commands)) { 1374 retval = SCTP_DISPOSITION_CONSUME; 1375 goto cleanup_asoc; 1376 } 1377 } 1378 1379 sctp_tietags_populate(new_asoc, asoc); 1380 1381 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1382 1383 /* If there are errors need to be reported for unknown parameters, 1384 * make sure to reserve enough room in the INIT ACK for them. 1385 */ 1386 len = 0; 1387 if (err_chunk) { 1388 len = ntohs(err_chunk->chunk_hdr->length) - 1389 sizeof(sctp_chunkhdr_t); 1390 } 1391 1392 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 1393 goto nomem; 1394 1395 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1396 if (!repl) 1397 goto nomem; 1398 1399 /* If there are errors need to be reported for unknown parameters, 1400 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1401 * parameter. 1402 */ 1403 if (err_chunk) { 1404 /* Get the "Unrecognized parameter" parameter(s) out of the 1405 * ERROR chunk generated by sctp_verify_init(). Since the 1406 * error cause code for "unknown parameter" and the 1407 * "Unrecognized parameter" type is the same, we can 1408 * construct the parameters in INIT ACK by copying the 1409 * ERROR causes over. 1410 */ 1411 unk_param = (sctp_unrecognized_param_t *) 1412 ((__u8 *)(err_chunk->chunk_hdr) + 1413 sizeof(sctp_chunkhdr_t)); 1414 /* Replace the cause code with the "Unrecognized parameter" 1415 * parameter type. 1416 */ 1417 sctp_addto_chunk(repl, len, unk_param); 1418 } 1419 1420 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1421 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1422 1423 /* 1424 * Note: After sending out INIT ACK with the State Cookie parameter, 1425 * "Z" MUST NOT allocate any resources for this new association. 1426 * Otherwise, "Z" will be vulnerable to resource attacks. 1427 */ 1428 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1429 retval = SCTP_DISPOSITION_CONSUME; 1430 1431 cleanup: 1432 if (err_chunk) 1433 sctp_chunk_free(err_chunk); 1434 return retval; 1435 nomem: 1436 retval = SCTP_DISPOSITION_NOMEM; 1437 goto cleanup; 1438 nomem_init: 1439 cleanup_asoc: 1440 sctp_association_free(new_asoc); 1441 goto cleanup; 1442 } 1443 1444 /* 1445 * Handle simultanous INIT. 1446 * This means we started an INIT and then we got an INIT request from 1447 * our peer. 1448 * 1449 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1450 * This usually indicates an initialization collision, i.e., each 1451 * endpoint is attempting, at about the same time, to establish an 1452 * association with the other endpoint. 1453 * 1454 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1455 * endpoint MUST respond with an INIT ACK using the same parameters it 1456 * sent in its original INIT chunk (including its Verification Tag, 1457 * unchanged). These original parameters are combined with those from the 1458 * newly received INIT chunk. The endpoint shall also generate a State 1459 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1460 * INIT to calculate the State Cookie. 1461 * 1462 * After that, the endpoint MUST NOT change its state, the T1-init 1463 * timer shall be left running and the corresponding TCB MUST NOT be 1464 * destroyed. The normal procedures for handling State Cookies when 1465 * a TCB exists will resolve the duplicate INITs to a single association. 1466 * 1467 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1468 * its Tie-Tags with the Tag information of itself and its peer (see 1469 * section 5.2.2 for a description of the Tie-Tags). 1470 * 1471 * Verification Tag: Not explicit, but an INIT can not have a valid 1472 * verification tag, so we skip the check. 1473 * 1474 * Inputs 1475 * (endpoint, asoc, chunk) 1476 * 1477 * Outputs 1478 * (asoc, reply_msg, msg_up, timers, counters) 1479 * 1480 * The return value is the disposition of the chunk. 1481 */ 1482 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1483 const struct sctp_association *asoc, 1484 const sctp_subtype_t type, 1485 void *arg, 1486 sctp_cmd_seq_t *commands) 1487 { 1488 /* Call helper to do the real work for both simulataneous and 1489 * duplicate INIT chunk handling. 1490 */ 1491 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1492 } 1493 1494 /* 1495 * Handle duplicated INIT messages. These are usually delayed 1496 * restransmissions. 1497 * 1498 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1499 * COOKIE-ECHOED and COOKIE-WAIT 1500 * 1501 * Unless otherwise stated, upon reception of an unexpected INIT for 1502 * this association, the endpoint shall generate an INIT ACK with a 1503 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1504 * current Verification Tag and peer's Verification Tag into a reserved 1505 * place within the state cookie. We shall refer to these locations as 1506 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1507 * containing this INIT ACK MUST carry a Verification Tag value equal to 1508 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1509 * MUST contain a new Initiation Tag (randomly generated see Section 1510 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1511 * existing parameters of the association (e.g. number of outbound 1512 * streams) into the INIT ACK and cookie. 1513 * 1514 * After sending out the INIT ACK, the endpoint shall take no further 1515 * actions, i.e., the existing association, including its current state, 1516 * and the corresponding TCB MUST NOT be changed. 1517 * 1518 * Note: Only when a TCB exists and the association is not in a COOKIE- 1519 * WAIT state are the Tie-Tags populated. For a normal association INIT 1520 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1521 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1522 * State Cookie are populated as specified in section 5.2.1. 1523 * 1524 * Verification Tag: Not specified, but an INIT has no way of knowing 1525 * what the verification tag could be, so we ignore it. 1526 * 1527 * Inputs 1528 * (endpoint, asoc, chunk) 1529 * 1530 * Outputs 1531 * (asoc, reply_msg, msg_up, timers, counters) 1532 * 1533 * The return value is the disposition of the chunk. 1534 */ 1535 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1536 const struct sctp_association *asoc, 1537 const sctp_subtype_t type, 1538 void *arg, 1539 sctp_cmd_seq_t *commands) 1540 { 1541 /* Call helper to do the real work for both simulataneous and 1542 * duplicate INIT chunk handling. 1543 */ 1544 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1545 } 1546 1547 1548 1549 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1550 * 1551 * Section 5.2.4 1552 * A) In this case, the peer may have restarted. 1553 */ 1554 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1555 const struct sctp_association *asoc, 1556 struct sctp_chunk *chunk, 1557 sctp_cmd_seq_t *commands, 1558 struct sctp_association *new_asoc) 1559 { 1560 sctp_init_chunk_t *peer_init; 1561 struct sctp_ulpevent *ev; 1562 struct sctp_chunk *repl; 1563 struct sctp_chunk *err; 1564 sctp_disposition_t disposition; 1565 1566 /* new_asoc is a brand-new association, so these are not yet 1567 * side effects--it is safe to run them here. 1568 */ 1569 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1570 1571 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1572 sctp_source(chunk), peer_init, 1573 GFP_ATOMIC)) 1574 goto nomem; 1575 1576 /* Make sure no new addresses are being added during the 1577 * restart. Though this is a pretty complicated attack 1578 * since you'd have to get inside the cookie. 1579 */ 1580 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1581 return SCTP_DISPOSITION_CONSUME; 1582 } 1583 1584 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1585 * the peer has restarted (Action A), it MUST NOT setup a new 1586 * association but instead resend the SHUTDOWN ACK and send an ERROR 1587 * chunk with a "Cookie Received while Shutting Down" error cause to 1588 * its peer. 1589 */ 1590 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1591 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1592 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1593 chunk, commands); 1594 if (SCTP_DISPOSITION_NOMEM == disposition) 1595 goto nomem; 1596 1597 err = sctp_make_op_error(asoc, chunk, 1598 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1599 NULL, 0); 1600 if (err) 1601 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1602 SCTP_CHUNK(err)); 1603 1604 return SCTP_DISPOSITION_CONSUME; 1605 } 1606 1607 /* For now, fail any unsent/unacked data. Consider the optional 1608 * choice of resending of this data. 1609 */ 1610 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1611 1612 /* Update the content of current association. */ 1613 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1614 1615 repl = sctp_make_cookie_ack(new_asoc, chunk); 1616 if (!repl) 1617 goto nomem; 1618 1619 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1620 1621 /* Report association restart to upper layer. */ 1622 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1623 new_asoc->c.sinit_num_ostreams, 1624 new_asoc->c.sinit_max_instreams, 1625 GFP_ATOMIC); 1626 if (!ev) 1627 goto nomem_ev; 1628 1629 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1630 return SCTP_DISPOSITION_CONSUME; 1631 1632 nomem_ev: 1633 sctp_chunk_free(repl); 1634 nomem: 1635 return SCTP_DISPOSITION_NOMEM; 1636 } 1637 1638 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1639 * 1640 * Section 5.2.4 1641 * B) In this case, both sides may be attempting to start an association 1642 * at about the same time but the peer endpoint started its INIT 1643 * after responding to the local endpoint's INIT 1644 */ 1645 /* This case represents an initialization collision. */ 1646 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1647 const struct sctp_association *asoc, 1648 struct sctp_chunk *chunk, 1649 sctp_cmd_seq_t *commands, 1650 struct sctp_association *new_asoc) 1651 { 1652 sctp_init_chunk_t *peer_init; 1653 struct sctp_ulpevent *ev; 1654 struct sctp_chunk *repl; 1655 1656 /* new_asoc is a brand-new association, so these are not yet 1657 * side effects--it is safe to run them here. 1658 */ 1659 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1660 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1661 sctp_source(chunk), peer_init, 1662 GFP_ATOMIC)) 1663 goto nomem; 1664 1665 /* Update the content of current association. */ 1666 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1667 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1668 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1669 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1670 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1671 1672 repl = sctp_make_cookie_ack(new_asoc, chunk); 1673 if (!repl) 1674 goto nomem; 1675 1676 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1677 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1678 1679 /* RFC 2960 5.1 Normal Establishment of an Association 1680 * 1681 * D) IMPLEMENTATION NOTE: An implementation may choose to 1682 * send the Communication Up notification to the SCTP user 1683 * upon reception of a valid COOKIE ECHO chunk. 1684 */ 1685 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0, 1686 new_asoc->c.sinit_num_ostreams, 1687 new_asoc->c.sinit_max_instreams, 1688 GFP_ATOMIC); 1689 if (!ev) 1690 goto nomem_ev; 1691 1692 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1693 1694 /* Sockets API Draft Section 5.3.1.6 1695 * When a peer sends a Adaption Layer Indication parameter , SCTP 1696 * delivers this notification to inform the application that of the 1697 * peers requested adaption layer. 1698 */ 1699 if (asoc->peer.adaption_ind) { 1700 ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC); 1701 if (!ev) 1702 goto nomem_ev; 1703 1704 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1705 SCTP_ULPEVENT(ev)); 1706 } 1707 1708 return SCTP_DISPOSITION_CONSUME; 1709 1710 nomem_ev: 1711 sctp_chunk_free(repl); 1712 nomem: 1713 return SCTP_DISPOSITION_NOMEM; 1714 } 1715 1716 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1717 * 1718 * Section 5.2.4 1719 * C) In this case, the local endpoint's cookie has arrived late. 1720 * Before it arrived, the local endpoint sent an INIT and received an 1721 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1722 * but a new tag of its own. 1723 */ 1724 /* This case represents an initialization collision. */ 1725 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1726 const struct sctp_association *asoc, 1727 struct sctp_chunk *chunk, 1728 sctp_cmd_seq_t *commands, 1729 struct sctp_association *new_asoc) 1730 { 1731 /* The cookie should be silently discarded. 1732 * The endpoint SHOULD NOT change states and should leave 1733 * any timers running. 1734 */ 1735 return SCTP_DISPOSITION_DISCARD; 1736 } 1737 1738 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1739 * 1740 * Section 5.2.4 1741 * 1742 * D) When both local and remote tags match the endpoint should always 1743 * enter the ESTABLISHED state, if it has not already done so. 1744 */ 1745 /* This case represents an initialization collision. */ 1746 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1747 const struct sctp_association *asoc, 1748 struct sctp_chunk *chunk, 1749 sctp_cmd_seq_t *commands, 1750 struct sctp_association *new_asoc) 1751 { 1752 struct sctp_ulpevent *ev = NULL; 1753 struct sctp_chunk *repl; 1754 1755 /* Clarification from Implementor's Guide: 1756 * D) When both local and remote tags match the endpoint should 1757 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1758 * It should stop any cookie timer that may be running and send 1759 * a COOKIE ACK. 1760 */ 1761 1762 /* Don't accidentally move back into established state. */ 1763 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1764 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1765 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1766 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1767 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1768 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1769 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1770 SCTP_NULL()); 1771 1772 /* RFC 2960 5.1 Normal Establishment of an Association 1773 * 1774 * D) IMPLEMENTATION NOTE: An implementation may choose 1775 * to send the Communication Up notification to the 1776 * SCTP user upon reception of a valid COOKIE 1777 * ECHO chunk. 1778 */ 1779 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, 1780 SCTP_COMM_UP, 0, 1781 new_asoc->c.sinit_num_ostreams, 1782 new_asoc->c.sinit_max_instreams, 1783 GFP_ATOMIC); 1784 if (!ev) 1785 goto nomem; 1786 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1787 SCTP_ULPEVENT(ev)); 1788 1789 /* Sockets API Draft Section 5.3.1.6 1790 * When a peer sends a Adaption Layer Indication parameter, 1791 * SCTP delivers this notification to inform the application 1792 * that of the peers requested adaption layer. 1793 */ 1794 if (new_asoc->peer.adaption_ind) { 1795 ev = sctp_ulpevent_make_adaption_indication(new_asoc, 1796 GFP_ATOMIC); 1797 if (!ev) 1798 goto nomem; 1799 1800 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1801 SCTP_ULPEVENT(ev)); 1802 } 1803 } 1804 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1805 1806 repl = sctp_make_cookie_ack(new_asoc, chunk); 1807 if (!repl) 1808 goto nomem; 1809 1810 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1811 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1812 1813 return SCTP_DISPOSITION_CONSUME; 1814 1815 nomem: 1816 if (ev) 1817 sctp_ulpevent_free(ev); 1818 return SCTP_DISPOSITION_NOMEM; 1819 } 1820 1821 /* 1822 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1823 * chunk was retransmitted and then delayed in the network. 1824 * 1825 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1826 * 1827 * Verification Tag: None. Do cookie validation. 1828 * 1829 * Inputs 1830 * (endpoint, asoc, chunk) 1831 * 1832 * Outputs 1833 * (asoc, reply_msg, msg_up, timers, counters) 1834 * 1835 * The return value is the disposition of the chunk. 1836 */ 1837 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1838 const struct sctp_association *asoc, 1839 const sctp_subtype_t type, 1840 void *arg, 1841 sctp_cmd_seq_t *commands) 1842 { 1843 sctp_disposition_t retval; 1844 struct sctp_chunk *chunk = arg; 1845 struct sctp_association *new_asoc; 1846 int error = 0; 1847 char action; 1848 struct sctp_chunk *err_chk_p; 1849 1850 /* Make sure that the chunk has a valid length from the protocol 1851 * perspective. In this case check to make sure we have at least 1852 * enough for the chunk header. Cookie length verification is 1853 * done later. 1854 */ 1855 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1856 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1857 commands); 1858 1859 /* "Decode" the chunk. We have no optional parameters so we 1860 * are in good shape. 1861 */ 1862 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1863 skb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1864 sizeof(sctp_chunkhdr_t)); 1865 1866 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1867 * of a duplicate COOKIE ECHO match the Verification Tags of the 1868 * current association, consider the State Cookie valid even if 1869 * the lifespan is exceeded. 1870 */ 1871 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1872 &err_chk_p); 1873 1874 /* FIXME: 1875 * If the re-build failed, what is the proper error path 1876 * from here? 1877 * 1878 * [We should abort the association. --piggy] 1879 */ 1880 if (!new_asoc) { 1881 /* FIXME: Several errors are possible. A bad cookie should 1882 * be silently discarded, but think about logging it too. 1883 */ 1884 switch (error) { 1885 case -SCTP_IERROR_NOMEM: 1886 goto nomem; 1887 1888 case -SCTP_IERROR_STALE_COOKIE: 1889 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 1890 err_chk_p); 1891 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1892 case -SCTP_IERROR_BAD_SIG: 1893 default: 1894 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1895 }; 1896 } 1897 1898 /* Compare the tie_tag in cookie with the verification tag of 1899 * current association. 1900 */ 1901 action = sctp_tietags_compare(new_asoc, asoc); 1902 1903 switch (action) { 1904 case 'A': /* Association restart. */ 1905 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 1906 new_asoc); 1907 break; 1908 1909 case 'B': /* Collision case B. */ 1910 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 1911 new_asoc); 1912 break; 1913 1914 case 'C': /* Collision case C. */ 1915 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 1916 new_asoc); 1917 break; 1918 1919 case 'D': /* Collision case D. */ 1920 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 1921 new_asoc); 1922 break; 1923 1924 default: /* Discard packet for all others. */ 1925 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1926 break; 1927 }; 1928 1929 /* Delete the tempory new association. */ 1930 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1931 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1932 1933 return retval; 1934 1935 nomem: 1936 return SCTP_DISPOSITION_NOMEM; 1937 } 1938 1939 /* 1940 * Process an ABORT. (SHUTDOWN-PENDING state) 1941 * 1942 * See sctp_sf_do_9_1_abort(). 1943 */ 1944 sctp_disposition_t sctp_sf_shutdown_pending_abort( 1945 const struct sctp_endpoint *ep, 1946 const struct sctp_association *asoc, 1947 const sctp_subtype_t type, 1948 void *arg, 1949 sctp_cmd_seq_t *commands) 1950 { 1951 struct sctp_chunk *chunk = arg; 1952 1953 if (!sctp_vtag_verify_either(chunk, asoc)) 1954 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1955 1956 /* Make sure that the ABORT chunk has a valid length. 1957 * Since this is an ABORT chunk, we have to discard it 1958 * because of the following text: 1959 * RFC 2960, Section 3.3.7 1960 * If an endpoint receives an ABORT with a format error or for an 1961 * association that doesn't exist, it MUST silently discard it. 1962 * Becasue the length is "invalid", we can't really discard just 1963 * as we do not know its true length. So, to be safe, discard the 1964 * packet. 1965 */ 1966 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 1967 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1968 1969 /* Stop the T5-shutdown guard timer. */ 1970 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1971 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 1972 1973 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 1974 } 1975 1976 /* 1977 * Process an ABORT. (SHUTDOWN-SENT state) 1978 * 1979 * See sctp_sf_do_9_1_abort(). 1980 */ 1981 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 1982 const struct sctp_association *asoc, 1983 const sctp_subtype_t type, 1984 void *arg, 1985 sctp_cmd_seq_t *commands) 1986 { 1987 struct sctp_chunk *chunk = arg; 1988 1989 if (!sctp_vtag_verify_either(chunk, asoc)) 1990 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1991 1992 /* Make sure that the ABORT chunk has a valid length. 1993 * Since this is an ABORT chunk, we have to discard it 1994 * because of the following text: 1995 * RFC 2960, Section 3.3.7 1996 * If an endpoint receives an ABORT with a format error or for an 1997 * association that doesn't exist, it MUST silently discard it. 1998 * Becasue the length is "invalid", we can't really discard just 1999 * as we do not know its true length. So, to be safe, discard the 2000 * packet. 2001 */ 2002 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2003 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2004 2005 /* Stop the T2-shutdown timer. */ 2006 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2007 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2008 2009 /* Stop the T5-shutdown guard timer. */ 2010 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2011 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2012 2013 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2014 } 2015 2016 /* 2017 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2018 * 2019 * See sctp_sf_do_9_1_abort(). 2020 */ 2021 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2022 const struct sctp_endpoint *ep, 2023 const struct sctp_association *asoc, 2024 const sctp_subtype_t type, 2025 void *arg, 2026 sctp_cmd_seq_t *commands) 2027 { 2028 /* The same T2 timer, so we should be able to use 2029 * common function with the SHUTDOWN-SENT state. 2030 */ 2031 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2032 } 2033 2034 /* 2035 * Handle an Error received in COOKIE_ECHOED state. 2036 * 2037 * Only handle the error type of stale COOKIE Error, the other errors will 2038 * be ignored. 2039 * 2040 * Inputs 2041 * (endpoint, asoc, chunk) 2042 * 2043 * Outputs 2044 * (asoc, reply_msg, msg_up, timers, counters) 2045 * 2046 * The return value is the disposition of the chunk. 2047 */ 2048 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2049 const struct sctp_association *asoc, 2050 const sctp_subtype_t type, 2051 void *arg, 2052 sctp_cmd_seq_t *commands) 2053 { 2054 struct sctp_chunk *chunk = arg; 2055 sctp_errhdr_t *err; 2056 2057 if (!sctp_vtag_verify(chunk, asoc)) 2058 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2059 2060 /* Make sure that the ERROR chunk has a valid length. 2061 * The parameter walking depends on this as well. 2062 */ 2063 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2064 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2065 commands); 2066 2067 /* Process the error here */ 2068 /* FUTURE FIXME: When PR-SCTP related and other optional 2069 * parms are emitted, this will have to change to handle multiple 2070 * errors. 2071 */ 2072 sctp_walk_errors(err, chunk->chunk_hdr) { 2073 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2074 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2075 arg, commands); 2076 } 2077 2078 /* It is possible to have malformed error causes, and that 2079 * will cause us to end the walk early. However, since 2080 * we are discarding the packet, there should be no adverse 2081 * affects. 2082 */ 2083 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2084 } 2085 2086 /* 2087 * Handle a Stale COOKIE Error 2088 * 2089 * Section: 5.2.6 Handle Stale COOKIE Error 2090 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2091 * one of the following three alternatives. 2092 * ... 2093 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2094 * Preservative parameter requesting an extension to the lifetime of 2095 * the State Cookie. When calculating the time extension, an 2096 * implementation SHOULD use the RTT information measured based on the 2097 * previous COOKIE ECHO / ERROR exchange, and should add no more 2098 * than 1 second beyond the measured RTT, due to long State Cookie 2099 * lifetimes making the endpoint more subject to a replay attack. 2100 * 2101 * Verification Tag: Not explicit, but safe to ignore. 2102 * 2103 * Inputs 2104 * (endpoint, asoc, chunk) 2105 * 2106 * Outputs 2107 * (asoc, reply_msg, msg_up, timers, counters) 2108 * 2109 * The return value is the disposition of the chunk. 2110 */ 2111 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2112 const struct sctp_association *asoc, 2113 const sctp_subtype_t type, 2114 void *arg, 2115 sctp_cmd_seq_t *commands) 2116 { 2117 struct sctp_chunk *chunk = arg; 2118 time_t stale; 2119 sctp_cookie_preserve_param_t bht; 2120 sctp_errhdr_t *err; 2121 struct sctp_chunk *reply; 2122 struct sctp_bind_addr *bp; 2123 int attempts = asoc->init_err_counter + 1; 2124 2125 if (attempts >= asoc->max_init_attempts) { 2126 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2127 SCTP_U32(SCTP_ERROR_STALE_COOKIE)); 2128 return SCTP_DISPOSITION_DELETE_TCB; 2129 } 2130 2131 err = (sctp_errhdr_t *)(chunk->skb->data); 2132 2133 /* When calculating the time extension, an implementation 2134 * SHOULD use the RTT information measured based on the 2135 * previous COOKIE ECHO / ERROR exchange, and should add no 2136 * more than 1 second beyond the measured RTT, due to long 2137 * State Cookie lifetimes making the endpoint more subject to 2138 * a replay attack. 2139 * Measure of Staleness's unit is usec. (1/1000000 sec) 2140 * Suggested Cookie Life-span Increment's unit is msec. 2141 * (1/1000 sec) 2142 * In general, if you use the suggested cookie life, the value 2143 * found in the field of measure of staleness should be doubled 2144 * to give ample time to retransmit the new cookie and thus 2145 * yield a higher probability of success on the reattempt. 2146 */ 2147 stale = ntohl(*(suseconds_t *)((u8 *)err + sizeof(sctp_errhdr_t))); 2148 stale = (stale * 2) / 1000; 2149 2150 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2151 bht.param_hdr.length = htons(sizeof(bht)); 2152 bht.lifespan_increment = htonl(stale); 2153 2154 /* Build that new INIT chunk. */ 2155 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2156 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2157 if (!reply) 2158 goto nomem; 2159 2160 sctp_addto_chunk(reply, sizeof(bht), &bht); 2161 2162 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2163 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2164 2165 /* Stop pending T3-rtx and heartbeat timers */ 2166 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2167 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2168 2169 /* Delete non-primary peer ip addresses since we are transitioning 2170 * back to the COOKIE-WAIT state 2171 */ 2172 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2173 2174 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2175 * resend 2176 */ 2177 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, 2178 SCTP_TRANSPORT(asoc->peer.primary_path)); 2179 2180 /* Cast away the const modifier, as we want to just 2181 * rerun it through as a sideffect. 2182 */ 2183 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2184 2185 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2186 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2187 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2188 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2189 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2190 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2191 2192 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2193 2194 return SCTP_DISPOSITION_CONSUME; 2195 2196 nomem: 2197 return SCTP_DISPOSITION_NOMEM; 2198 } 2199 2200 /* 2201 * Process an ABORT. 2202 * 2203 * Section: 9.1 2204 * After checking the Verification Tag, the receiving endpoint shall 2205 * remove the association from its record, and shall report the 2206 * termination to its upper layer. 2207 * 2208 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2209 * B) Rules for packet carrying ABORT: 2210 * 2211 * - The endpoint shall always fill in the Verification Tag field of the 2212 * outbound packet with the destination endpoint's tag value if it 2213 * is known. 2214 * 2215 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2216 * MUST follow the procedure described in Section 8.4. 2217 * 2218 * - The receiver MUST accept the packet if the Verification Tag 2219 * matches either its own tag, OR the tag of its peer. Otherwise, the 2220 * receiver MUST silently discard the packet and take no further 2221 * action. 2222 * 2223 * Inputs 2224 * (endpoint, asoc, chunk) 2225 * 2226 * Outputs 2227 * (asoc, reply_msg, msg_up, timers, counters) 2228 * 2229 * The return value is the disposition of the chunk. 2230 */ 2231 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2232 const struct sctp_association *asoc, 2233 const sctp_subtype_t type, 2234 void *arg, 2235 sctp_cmd_seq_t *commands) 2236 { 2237 struct sctp_chunk *chunk = arg; 2238 unsigned len; 2239 __u16 error = SCTP_ERROR_NO_ERROR; 2240 2241 if (!sctp_vtag_verify_either(chunk, asoc)) 2242 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2243 2244 /* Make sure that the ABORT chunk has a valid length. 2245 * Since this is an ABORT chunk, we have to discard it 2246 * because of the following text: 2247 * RFC 2960, Section 3.3.7 2248 * If an endpoint receives an ABORT with a format error or for an 2249 * association that doesn't exist, it MUST silently discard it. 2250 * Becasue the length is "invalid", we can't really discard just 2251 * as we do not know its true length. So, to be safe, discard the 2252 * packet. 2253 */ 2254 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2255 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2256 2257 /* See if we have an error cause code in the chunk. */ 2258 len = ntohs(chunk->chunk_hdr->length); 2259 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2260 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2261 2262 /* ASSOC_FAILED will DELETE_TCB. */ 2263 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(error)); 2264 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2265 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2266 2267 return SCTP_DISPOSITION_ABORT; 2268 } 2269 2270 /* 2271 * Process an ABORT. (COOKIE-WAIT state) 2272 * 2273 * See sctp_sf_do_9_1_abort() above. 2274 */ 2275 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2276 const struct sctp_association *asoc, 2277 const sctp_subtype_t type, 2278 void *arg, 2279 sctp_cmd_seq_t *commands) 2280 { 2281 struct sctp_chunk *chunk = arg; 2282 unsigned len; 2283 __u16 error = SCTP_ERROR_NO_ERROR; 2284 2285 if (!sctp_vtag_verify_either(chunk, asoc)) 2286 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2287 2288 /* Make sure that the ABORT chunk has a valid length. 2289 * Since this is an ABORT chunk, we have to discard it 2290 * because of the following text: 2291 * RFC 2960, Section 3.3.7 2292 * If an endpoint receives an ABORT with a format error or for an 2293 * association that doesn't exist, it MUST silently discard it. 2294 * Becasue the length is "invalid", we can't really discard just 2295 * as we do not know its true length. So, to be safe, discard the 2296 * packet. 2297 */ 2298 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2299 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2300 2301 /* See if we have an error cause code in the chunk. */ 2302 len = ntohs(chunk->chunk_hdr->length); 2303 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2304 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2305 2306 return sctp_stop_t1_and_abort(commands, error, asoc, chunk->transport); 2307 } 2308 2309 /* 2310 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2311 */ 2312 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2313 const struct sctp_association *asoc, 2314 const sctp_subtype_t type, 2315 void *arg, 2316 sctp_cmd_seq_t *commands) 2317 { 2318 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, asoc, 2319 (struct sctp_transport *)arg); 2320 } 2321 2322 /* 2323 * Process an ABORT. (COOKIE-ECHOED state) 2324 */ 2325 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2326 const struct sctp_association *asoc, 2327 const sctp_subtype_t type, 2328 void *arg, 2329 sctp_cmd_seq_t *commands) 2330 { 2331 /* There is a single T1 timer, so we should be able to use 2332 * common function with the COOKIE-WAIT state. 2333 */ 2334 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2335 } 2336 2337 /* 2338 * Stop T1 timer and abort association with "INIT failed". 2339 * 2340 * This is common code called by several sctp_sf_*_abort() functions above. 2341 */ 2342 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2343 __u16 error, 2344 const struct sctp_association *asoc, 2345 struct sctp_transport *transport) 2346 { 2347 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2348 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2349 SCTP_STATE(SCTP_STATE_CLOSED)); 2350 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2351 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2352 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2353 /* CMD_INIT_FAILED will DELETE_TCB. */ 2354 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2355 SCTP_U32(error)); 2356 return SCTP_DISPOSITION_ABORT; 2357 } 2358 2359 /* 2360 * sctp_sf_do_9_2_shut 2361 * 2362 * Section: 9.2 2363 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2364 * - enter the SHUTDOWN-RECEIVED state, 2365 * 2366 * - stop accepting new data from its SCTP user 2367 * 2368 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2369 * that all its outstanding DATA chunks have been received by the 2370 * SHUTDOWN sender. 2371 * 2372 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2373 * send a SHUTDOWN in response to a ULP request. And should discard 2374 * subsequent SHUTDOWN chunks. 2375 * 2376 * If there are still outstanding DATA chunks left, the SHUTDOWN 2377 * receiver shall continue to follow normal data transmission 2378 * procedures defined in Section 6 until all outstanding DATA chunks 2379 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2380 * new data from its SCTP user. 2381 * 2382 * Verification Tag: 8.5 Verification Tag [Normal verification] 2383 * 2384 * Inputs 2385 * (endpoint, asoc, chunk) 2386 * 2387 * Outputs 2388 * (asoc, reply_msg, msg_up, timers, counters) 2389 * 2390 * The return value is the disposition of the chunk. 2391 */ 2392 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2393 const struct sctp_association *asoc, 2394 const sctp_subtype_t type, 2395 void *arg, 2396 sctp_cmd_seq_t *commands) 2397 { 2398 struct sctp_chunk *chunk = arg; 2399 sctp_shutdownhdr_t *sdh; 2400 sctp_disposition_t disposition; 2401 struct sctp_ulpevent *ev; 2402 2403 if (!sctp_vtag_verify(chunk, asoc)) 2404 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2405 2406 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2407 if (!sctp_chunk_length_valid(chunk, 2408 sizeof(struct sctp_shutdown_chunk_t))) 2409 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2410 commands); 2411 2412 /* Convert the elaborate header. */ 2413 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2414 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2415 chunk->subh.shutdown_hdr = sdh; 2416 2417 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2418 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2419 * inform the application that it should cease sending data. 2420 */ 2421 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2422 if (!ev) { 2423 disposition = SCTP_DISPOSITION_NOMEM; 2424 goto out; 2425 } 2426 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2427 2428 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2429 * - enter the SHUTDOWN-RECEIVED state, 2430 * - stop accepting new data from its SCTP user 2431 * 2432 * [This is implicit in the new state.] 2433 */ 2434 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2435 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2436 disposition = SCTP_DISPOSITION_CONSUME; 2437 2438 if (sctp_outq_is_empty(&asoc->outqueue)) { 2439 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2440 arg, commands); 2441 } 2442 2443 if (SCTP_DISPOSITION_NOMEM == disposition) 2444 goto out; 2445 2446 /* - verify, by checking the Cumulative TSN Ack field of the 2447 * chunk, that all its outstanding DATA chunks have been 2448 * received by the SHUTDOWN sender. 2449 */ 2450 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2451 SCTP_U32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2452 2453 out: 2454 return disposition; 2455 } 2456 2457 /* RFC 2960 9.2 2458 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2459 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2460 * transport addresses (either in the IP addresses or in the INIT chunk) 2461 * that belong to this association, it should discard the INIT chunk and 2462 * retransmit the SHUTDOWN ACK chunk. 2463 */ 2464 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2465 const struct sctp_association *asoc, 2466 const sctp_subtype_t type, 2467 void *arg, 2468 sctp_cmd_seq_t *commands) 2469 { 2470 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2471 struct sctp_chunk *reply; 2472 2473 /* Since we are not going to really process this INIT, there 2474 * is no point in verifying chunk boundries. Just generate 2475 * the SHUTDOWN ACK. 2476 */ 2477 reply = sctp_make_shutdown_ack(asoc, chunk); 2478 if (NULL == reply) 2479 goto nomem; 2480 2481 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2482 * the T2-SHUTDOWN timer. 2483 */ 2484 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2485 2486 /* and restart the T2-shutdown timer. */ 2487 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2488 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2489 2490 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2491 2492 return SCTP_DISPOSITION_CONSUME; 2493 nomem: 2494 return SCTP_DISPOSITION_NOMEM; 2495 } 2496 2497 /* 2498 * sctp_sf_do_ecn_cwr 2499 * 2500 * Section: Appendix A: Explicit Congestion Notification 2501 * 2502 * CWR: 2503 * 2504 * RFC 2481 details a specific bit for a sender to send in the header of 2505 * its next outbound TCP segment to indicate to its peer that it has 2506 * reduced its congestion window. This is termed the CWR bit. For 2507 * SCTP the same indication is made by including the CWR chunk. 2508 * This chunk contains one data element, i.e. the TSN number that 2509 * was sent in the ECNE chunk. This element represents the lowest 2510 * TSN number in the datagram that was originally marked with the 2511 * CE bit. 2512 * 2513 * Verification Tag: 8.5 Verification Tag [Normal verification] 2514 * Inputs 2515 * (endpoint, asoc, chunk) 2516 * 2517 * Outputs 2518 * (asoc, reply_msg, msg_up, timers, counters) 2519 * 2520 * The return value is the disposition of the chunk. 2521 */ 2522 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2523 const struct sctp_association *asoc, 2524 const sctp_subtype_t type, 2525 void *arg, 2526 sctp_cmd_seq_t *commands) 2527 { 2528 sctp_cwrhdr_t *cwr; 2529 struct sctp_chunk *chunk = arg; 2530 2531 if (!sctp_vtag_verify(chunk, asoc)) 2532 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2533 2534 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2535 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2536 commands); 2537 2538 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2539 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2540 2541 cwr->lowest_tsn = ntohl(cwr->lowest_tsn); 2542 2543 /* Does this CWR ack the last sent congestion notification? */ 2544 if (TSN_lte(asoc->last_ecne_tsn, cwr->lowest_tsn)) { 2545 /* Stop sending ECNE. */ 2546 sctp_add_cmd_sf(commands, 2547 SCTP_CMD_ECN_CWR, 2548 SCTP_U32(cwr->lowest_tsn)); 2549 } 2550 return SCTP_DISPOSITION_CONSUME; 2551 } 2552 2553 /* 2554 * sctp_sf_do_ecne 2555 * 2556 * Section: Appendix A: Explicit Congestion Notification 2557 * 2558 * ECN-Echo 2559 * 2560 * RFC 2481 details a specific bit for a receiver to send back in its 2561 * TCP acknowledgements to notify the sender of the Congestion 2562 * Experienced (CE) bit having arrived from the network. For SCTP this 2563 * same indication is made by including the ECNE chunk. This chunk 2564 * contains one data element, i.e. the lowest TSN associated with the IP 2565 * datagram marked with the CE bit..... 2566 * 2567 * Verification Tag: 8.5 Verification Tag [Normal verification] 2568 * Inputs 2569 * (endpoint, asoc, chunk) 2570 * 2571 * Outputs 2572 * (asoc, reply_msg, msg_up, timers, counters) 2573 * 2574 * The return value is the disposition of the chunk. 2575 */ 2576 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2577 const struct sctp_association *asoc, 2578 const sctp_subtype_t type, 2579 void *arg, 2580 sctp_cmd_seq_t *commands) 2581 { 2582 sctp_ecnehdr_t *ecne; 2583 struct sctp_chunk *chunk = arg; 2584 2585 if (!sctp_vtag_verify(chunk, asoc)) 2586 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2587 2588 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2589 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2590 commands); 2591 2592 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2593 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2594 2595 /* If this is a newer ECNE than the last CWR packet we sent out */ 2596 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2597 SCTP_U32(ntohl(ecne->lowest_tsn))); 2598 2599 return SCTP_DISPOSITION_CONSUME; 2600 } 2601 2602 /* 2603 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2604 * 2605 * The SCTP endpoint MUST always acknowledge the reception of each valid 2606 * DATA chunk. 2607 * 2608 * The guidelines on delayed acknowledgement algorithm specified in 2609 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2610 * acknowledgement SHOULD be generated for at least every second packet 2611 * (not every second DATA chunk) received, and SHOULD be generated within 2612 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2613 * situations it may be beneficial for an SCTP transmitter to be more 2614 * conservative than the algorithms detailed in this document allow. 2615 * However, an SCTP transmitter MUST NOT be more aggressive than the 2616 * following algorithms allow. 2617 * 2618 * A SCTP receiver MUST NOT generate more than one SACK for every 2619 * incoming packet, other than to update the offered window as the 2620 * receiving application consumes new data. 2621 * 2622 * Verification Tag: 8.5 Verification Tag [Normal verification] 2623 * 2624 * Inputs 2625 * (endpoint, asoc, chunk) 2626 * 2627 * Outputs 2628 * (asoc, reply_msg, msg_up, timers, counters) 2629 * 2630 * The return value is the disposition of the chunk. 2631 */ 2632 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2633 const struct sctp_association *asoc, 2634 const sctp_subtype_t type, 2635 void *arg, 2636 sctp_cmd_seq_t *commands) 2637 { 2638 struct sctp_chunk *chunk = arg; 2639 int error; 2640 2641 if (!sctp_vtag_verify(chunk, asoc)) { 2642 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2643 SCTP_NULL()); 2644 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2645 } 2646 2647 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2648 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2649 commands); 2650 2651 error = sctp_eat_data(asoc, chunk, commands ); 2652 switch (error) { 2653 case SCTP_IERROR_NO_ERROR: 2654 break; 2655 case SCTP_IERROR_HIGH_TSN: 2656 case SCTP_IERROR_BAD_STREAM: 2657 goto discard_noforce; 2658 case SCTP_IERROR_DUP_TSN: 2659 case SCTP_IERROR_IGNORE_TSN: 2660 goto discard_force; 2661 case SCTP_IERROR_NO_DATA: 2662 goto consume; 2663 default: 2664 BUG(); 2665 } 2666 2667 if (asoc->autoclose) { 2668 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2669 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2670 } 2671 2672 /* If this is the last chunk in a packet, we need to count it 2673 * toward sack generation. Note that we need to SACK every 2674 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2675 * THEM. We elect to NOT generate SACK's if the chunk fails 2676 * the verification tag test. 2677 * 2678 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2679 * 2680 * The SCTP endpoint MUST always acknowledge the reception of 2681 * each valid DATA chunk. 2682 * 2683 * The guidelines on delayed acknowledgement algorithm 2684 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2685 * Specifically, an acknowledgement SHOULD be generated for at 2686 * least every second packet (not every second DATA chunk) 2687 * received, and SHOULD be generated within 200 ms of the 2688 * arrival of any unacknowledged DATA chunk. In some 2689 * situations it may be beneficial for an SCTP transmitter to 2690 * be more conservative than the algorithms detailed in this 2691 * document allow. However, an SCTP transmitter MUST NOT be 2692 * more aggressive than the following algorithms allow. 2693 */ 2694 if (chunk->end_of_packet) { 2695 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2696 2697 /* Start the SACK timer. */ 2698 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2699 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 2700 } 2701 2702 return SCTP_DISPOSITION_CONSUME; 2703 2704 discard_force: 2705 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2706 * 2707 * When a packet arrives with duplicate DATA chunk(s) and with 2708 * no new DATA chunk(s), the endpoint MUST immediately send a 2709 * SACK with no delay. If a packet arrives with duplicate 2710 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2711 * MAY immediately send a SACK. Normally receipt of duplicate 2712 * DATA chunks will occur when the original SACK chunk was lost 2713 * and the peer's RTO has expired. The duplicate TSN number(s) 2714 * SHOULD be reported in the SACK as duplicate. 2715 */ 2716 /* In our case, we split the MAY SACK advice up whether or not 2717 * the last chunk is a duplicate.' 2718 */ 2719 if (chunk->end_of_packet) 2720 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2721 return SCTP_DISPOSITION_DISCARD; 2722 2723 discard_noforce: 2724 if (chunk->end_of_packet) { 2725 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2726 2727 /* Start the SACK timer. */ 2728 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2729 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 2730 } 2731 return SCTP_DISPOSITION_DISCARD; 2732 consume: 2733 return SCTP_DISPOSITION_CONSUME; 2734 2735 } 2736 2737 /* 2738 * sctp_sf_eat_data_fast_4_4 2739 * 2740 * Section: 4 (4) 2741 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2742 * DATA chunks without delay. 2743 * 2744 * Verification Tag: 8.5 Verification Tag [Normal verification] 2745 * Inputs 2746 * (endpoint, asoc, chunk) 2747 * 2748 * Outputs 2749 * (asoc, reply_msg, msg_up, timers, counters) 2750 * 2751 * The return value is the disposition of the chunk. 2752 */ 2753 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2754 const struct sctp_association *asoc, 2755 const sctp_subtype_t type, 2756 void *arg, 2757 sctp_cmd_seq_t *commands) 2758 { 2759 struct sctp_chunk *chunk = arg; 2760 int error; 2761 2762 if (!sctp_vtag_verify(chunk, asoc)) { 2763 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2764 SCTP_NULL()); 2765 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2766 } 2767 2768 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2769 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2770 commands); 2771 2772 error = sctp_eat_data(asoc, chunk, commands ); 2773 switch (error) { 2774 case SCTP_IERROR_NO_ERROR: 2775 case SCTP_IERROR_HIGH_TSN: 2776 case SCTP_IERROR_DUP_TSN: 2777 case SCTP_IERROR_IGNORE_TSN: 2778 case SCTP_IERROR_BAD_STREAM: 2779 break; 2780 case SCTP_IERROR_NO_DATA: 2781 goto consume; 2782 default: 2783 BUG(); 2784 } 2785 2786 /* Go a head and force a SACK, since we are shutting down. */ 2787 2788 /* Implementor's Guide. 2789 * 2790 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 2791 * respond to each received packet containing one or more DATA chunk(s) 2792 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 2793 */ 2794 if (chunk->end_of_packet) { 2795 /* We must delay the chunk creation since the cumulative 2796 * TSN has not been updated yet. 2797 */ 2798 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 2799 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2800 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2801 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2802 } 2803 2804 consume: 2805 return SCTP_DISPOSITION_CONSUME; 2806 } 2807 2808 /* 2809 * Section: 6.2 Processing a Received SACK 2810 * D) Any time a SACK arrives, the endpoint performs the following: 2811 * 2812 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 2813 * then drop the SACK. Since Cumulative TSN Ack is monotonically 2814 * increasing, a SACK whose Cumulative TSN Ack is less than the 2815 * Cumulative TSN Ack Point indicates an out-of-order SACK. 2816 * 2817 * ii) Set rwnd equal to the newly received a_rwnd minus the number 2818 * of bytes still outstanding after processing the Cumulative TSN Ack 2819 * and the Gap Ack Blocks. 2820 * 2821 * iii) If the SACK is missing a TSN that was previously 2822 * acknowledged via a Gap Ack Block (e.g., the data receiver 2823 * reneged on the data), then mark the corresponding DATA chunk 2824 * as available for retransmit: Mark it as missing for fast 2825 * retransmit as described in Section 7.2.4 and if no retransmit 2826 * timer is running for the destination address to which the DATA 2827 * chunk was originally transmitted, then T3-rtx is started for 2828 * that destination address. 2829 * 2830 * Verification Tag: 8.5 Verification Tag [Normal verification] 2831 * 2832 * Inputs 2833 * (endpoint, asoc, chunk) 2834 * 2835 * Outputs 2836 * (asoc, reply_msg, msg_up, timers, counters) 2837 * 2838 * The return value is the disposition of the chunk. 2839 */ 2840 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 2841 const struct sctp_association *asoc, 2842 const sctp_subtype_t type, 2843 void *arg, 2844 sctp_cmd_seq_t *commands) 2845 { 2846 struct sctp_chunk *chunk = arg; 2847 sctp_sackhdr_t *sackh; 2848 __u32 ctsn; 2849 2850 if (!sctp_vtag_verify(chunk, asoc)) 2851 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2852 2853 /* Make sure that the SACK chunk has a valid length. */ 2854 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 2855 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2856 commands); 2857 2858 /* Pull the SACK chunk from the data buffer */ 2859 sackh = sctp_sm_pull_sack(chunk); 2860 /* Was this a bogus SACK? */ 2861 if (!sackh) 2862 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2863 chunk->subh.sack_hdr = sackh; 2864 ctsn = ntohl(sackh->cum_tsn_ack); 2865 2866 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 2867 * Ack Point, then drop the SACK. Since Cumulative TSN 2868 * Ack is monotonically increasing, a SACK whose 2869 * Cumulative TSN Ack is less than the Cumulative TSN Ack 2870 * Point indicates an out-of-order SACK. 2871 */ 2872 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2873 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2874 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2875 return SCTP_DISPOSITION_DISCARD; 2876 } 2877 2878 /* Return this SACK for further processing. */ 2879 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 2880 2881 /* Note: We do the rest of the work on the PROCESS_SACK 2882 * sideeffect. 2883 */ 2884 return SCTP_DISPOSITION_CONSUME; 2885 } 2886 2887 /* 2888 * Generate an ABORT in response to a packet. 2889 * 2890 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 2891 * 2892 * 8) The receiver should respond to the sender of the OOTB packet with 2893 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 2894 * MUST fill in the Verification Tag field of the outbound packet 2895 * with the value found in the Verification Tag field of the OOTB 2896 * packet and set the T-bit in the Chunk Flags to indicate that the 2897 * Verification Tag is reflected. After sending this ABORT, the 2898 * receiver of the OOTB packet shall discard the OOTB packet and take 2899 * no further action. 2900 * 2901 * Verification Tag: 2902 * 2903 * The return value is the disposition of the chunk. 2904 */ 2905 sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 2906 const struct sctp_association *asoc, 2907 const sctp_subtype_t type, 2908 void *arg, 2909 sctp_cmd_seq_t *commands) 2910 { 2911 struct sctp_packet *packet = NULL; 2912 struct sctp_chunk *chunk = arg; 2913 struct sctp_chunk *abort; 2914 2915 packet = sctp_ootb_pkt_new(asoc, chunk); 2916 2917 if (packet) { 2918 /* Make an ABORT. The T bit will be set if the asoc 2919 * is NULL. 2920 */ 2921 abort = sctp_make_abort(asoc, chunk, 0); 2922 if (!abort) { 2923 sctp_ootb_pkt_free(packet); 2924 return SCTP_DISPOSITION_NOMEM; 2925 } 2926 2927 /* Reflect vtag if T-Bit is set */ 2928 if (sctp_test_T_bit(abort)) 2929 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 2930 2931 /* Set the skb to the belonging sock for accounting. */ 2932 abort->skb->sk = ep->base.sk; 2933 2934 sctp_packet_append_chunk(packet, abort); 2935 2936 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 2937 SCTP_PACKET(packet)); 2938 2939 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 2940 2941 return SCTP_DISPOSITION_CONSUME; 2942 } 2943 2944 return SCTP_DISPOSITION_NOMEM; 2945 } 2946 2947 /* 2948 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 2949 * event as ULP notification for each cause included in the chunk. 2950 * 2951 * API 5.3.1.3 - SCTP_REMOTE_ERROR 2952 * 2953 * The return value is the disposition of the chunk. 2954 */ 2955 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 2956 const struct sctp_association *asoc, 2957 const sctp_subtype_t type, 2958 void *arg, 2959 sctp_cmd_seq_t *commands) 2960 { 2961 struct sctp_chunk *chunk = arg; 2962 struct sctp_ulpevent *ev; 2963 2964 if (!sctp_vtag_verify(chunk, asoc)) 2965 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2966 2967 /* Make sure that the ERROR chunk has a valid length. */ 2968 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2969 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2970 commands); 2971 2972 while (chunk->chunk_end > chunk->skb->data) { 2973 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 2974 GFP_ATOMIC); 2975 if (!ev) 2976 goto nomem; 2977 2978 if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP, 2979 SCTP_ULPEVENT(ev))) { 2980 sctp_ulpevent_free(ev); 2981 goto nomem; 2982 } 2983 2984 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 2985 SCTP_CHUNK(chunk)); 2986 } 2987 return SCTP_DISPOSITION_CONSUME; 2988 2989 nomem: 2990 return SCTP_DISPOSITION_NOMEM; 2991 } 2992 2993 /* 2994 * Process an inbound SHUTDOWN ACK. 2995 * 2996 * From Section 9.2: 2997 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 2998 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 2999 * peer, and remove all record of the association. 3000 * 3001 * The return value is the disposition. 3002 */ 3003 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3004 const struct sctp_association *asoc, 3005 const sctp_subtype_t type, 3006 void *arg, 3007 sctp_cmd_seq_t *commands) 3008 { 3009 struct sctp_chunk *chunk = arg; 3010 struct sctp_chunk *reply; 3011 struct sctp_ulpevent *ev; 3012 3013 if (!sctp_vtag_verify(chunk, asoc)) 3014 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3015 3016 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3017 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3018 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3019 commands); 3020 3021 /* 10.2 H) SHUTDOWN COMPLETE notification 3022 * 3023 * When SCTP completes the shutdown procedures (section 9.2) this 3024 * notification is passed to the upper layer. 3025 */ 3026 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3027 0, 0, 0, GFP_ATOMIC); 3028 if (!ev) 3029 goto nomem; 3030 3031 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3032 3033 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3034 * stop the T2-shutdown timer, 3035 */ 3036 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3037 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3038 3039 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3040 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3041 3042 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3043 reply = sctp_make_shutdown_complete(asoc, chunk); 3044 if (!reply) 3045 goto nomem; 3046 3047 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3048 SCTP_STATE(SCTP_STATE_CLOSED)); 3049 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3050 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3051 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3052 3053 /* ...and remove all record of the association. */ 3054 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3055 return SCTP_DISPOSITION_DELETE_TCB; 3056 3057 nomem: 3058 return SCTP_DISPOSITION_NOMEM; 3059 } 3060 3061 /* 3062 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3063 * 3064 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3065 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3066 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3067 * packet must fill in the Verification Tag field of the outbound 3068 * packet with the Verification Tag received in the SHUTDOWN ACK and 3069 * set the T-bit in the Chunk Flags to indicate that the Verification 3070 * Tag is reflected. 3071 * 3072 * 8) The receiver should respond to the sender of the OOTB packet with 3073 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3074 * MUST fill in the Verification Tag field of the outbound packet 3075 * with the value found in the Verification Tag field of the OOTB 3076 * packet and set the T-bit in the Chunk Flags to indicate that the 3077 * Verification Tag is reflected. After sending this ABORT, the 3078 * receiver of the OOTB packet shall discard the OOTB packet and take 3079 * no further action. 3080 */ 3081 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3082 const struct sctp_association *asoc, 3083 const sctp_subtype_t type, 3084 void *arg, 3085 sctp_cmd_seq_t *commands) 3086 { 3087 struct sctp_chunk *chunk = arg; 3088 struct sk_buff *skb = chunk->skb; 3089 sctp_chunkhdr_t *ch; 3090 __u8 *ch_end; 3091 int ootb_shut_ack = 0; 3092 3093 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3094 3095 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3096 do { 3097 /* Break out if chunk length is less then minimal. */ 3098 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3099 break; 3100 3101 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3102 3103 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3104 ootb_shut_ack = 1; 3105 3106 /* RFC 2960, Section 3.3.7 3107 * Moreover, under any circumstances, an endpoint that 3108 * receives an ABORT MUST NOT respond to that ABORT by 3109 * sending an ABORT of its own. 3110 */ 3111 if (SCTP_CID_ABORT == ch->type) 3112 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3113 3114 ch = (sctp_chunkhdr_t *) ch_end; 3115 } while (ch_end < skb->tail); 3116 3117 if (ootb_shut_ack) 3118 sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3119 else 3120 sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3121 3122 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3123 } 3124 3125 /* 3126 * Handle an "Out of the blue" SHUTDOWN ACK. 3127 * 3128 * Section: 8.4 5, sctpimpguide 2.41. 3129 * 3130 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3131 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3132 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3133 * packet must fill in the Verification Tag field of the outbound 3134 * packet with the Verification Tag received in the SHUTDOWN ACK and 3135 * set the T-bit in the Chunk Flags to indicate that the Verification 3136 * Tag is reflected. 3137 * 3138 * Inputs 3139 * (endpoint, asoc, type, arg, commands) 3140 * 3141 * Outputs 3142 * (sctp_disposition_t) 3143 * 3144 * The return value is the disposition of the chunk. 3145 */ 3146 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3147 const struct sctp_association *asoc, 3148 const sctp_subtype_t type, 3149 void *arg, 3150 sctp_cmd_seq_t *commands) 3151 { 3152 struct sctp_packet *packet = NULL; 3153 struct sctp_chunk *chunk = arg; 3154 struct sctp_chunk *shut; 3155 3156 packet = sctp_ootb_pkt_new(asoc, chunk); 3157 3158 if (packet) { 3159 /* Make an SHUTDOWN_COMPLETE. 3160 * The T bit will be set if the asoc is NULL. 3161 */ 3162 shut = sctp_make_shutdown_complete(asoc, chunk); 3163 if (!shut) { 3164 sctp_ootb_pkt_free(packet); 3165 return SCTP_DISPOSITION_NOMEM; 3166 } 3167 3168 /* Reflect vtag if T-Bit is set */ 3169 if (sctp_test_T_bit(shut)) 3170 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3171 3172 /* Set the skb to the belonging sock for accounting. */ 3173 shut->skb->sk = ep->base.sk; 3174 3175 sctp_packet_append_chunk(packet, shut); 3176 3177 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3178 SCTP_PACKET(packet)); 3179 3180 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3181 3182 /* If the chunk length is invalid, we don't want to process 3183 * the reset of the packet. 3184 */ 3185 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3186 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3187 3188 return SCTP_DISPOSITION_CONSUME; 3189 } 3190 3191 return SCTP_DISPOSITION_NOMEM; 3192 } 3193 3194 /* 3195 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3196 * 3197 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3198 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3199 * procedures in section 8.4 SHOULD be followed, in other words it 3200 * should be treated as an Out Of The Blue packet. 3201 * [This means that we do NOT check the Verification Tag on these 3202 * chunks. --piggy ] 3203 * 3204 */ 3205 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3206 const struct sctp_association *asoc, 3207 const sctp_subtype_t type, 3208 void *arg, 3209 sctp_cmd_seq_t *commands) 3210 { 3211 /* Although we do have an association in this case, it corresponds 3212 * to a restarted association. So the packet is treated as an OOTB 3213 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3214 * called with a NULL association. 3215 */ 3216 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3217 } 3218 3219 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3220 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3221 const struct sctp_association *asoc, 3222 const sctp_subtype_t type, void *arg, 3223 sctp_cmd_seq_t *commands) 3224 { 3225 struct sctp_chunk *chunk = arg; 3226 struct sctp_chunk *asconf_ack = NULL; 3227 sctp_addiphdr_t *hdr; 3228 __u32 serial; 3229 3230 if (!sctp_vtag_verify(chunk, asoc)) { 3231 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3232 SCTP_NULL()); 3233 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3234 } 3235 3236 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3237 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3238 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3239 commands); 3240 3241 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3242 serial = ntohl(hdr->serial); 3243 3244 /* ADDIP 4.2 C1) Compare the value of the serial number to the value 3245 * the endpoint stored in a new association variable 3246 * 'Peer-Serial-Number'. 3247 */ 3248 if (serial == asoc->peer.addip_serial + 1) { 3249 /* ADDIP 4.2 C2) If the value found in the serial number is 3250 * equal to the ('Peer-Serial-Number' + 1), the endpoint MUST 3251 * do V1-V5. 3252 */ 3253 asconf_ack = sctp_process_asconf((struct sctp_association *) 3254 asoc, chunk); 3255 if (!asconf_ack) 3256 return SCTP_DISPOSITION_NOMEM; 3257 } else if (serial == asoc->peer.addip_serial) { 3258 /* ADDIP 4.2 C3) If the value found in the serial number is 3259 * equal to the value stored in the 'Peer-Serial-Number' 3260 * IMPLEMENTATION NOTE: As an optimization a receiver may wish 3261 * to save the last ASCONF-ACK for some predetermined period of 3262 * time and instead of re-processing the ASCONF (with the same 3263 * serial number) it may just re-transmit the ASCONF-ACK. 3264 */ 3265 if (asoc->addip_last_asconf_ack) 3266 asconf_ack = asoc->addip_last_asconf_ack; 3267 else 3268 return SCTP_DISPOSITION_DISCARD; 3269 } else { 3270 /* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since 3271 * it must be either a stale packet or from an attacker. 3272 */ 3273 return SCTP_DISPOSITION_DISCARD; 3274 } 3275 3276 /* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent 3277 * back to the source address contained in the IP header of the ASCONF 3278 * being responded to. 3279 */ 3280 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3281 3282 return SCTP_DISPOSITION_CONSUME; 3283 } 3284 3285 /* 3286 * ADDIP Section 4.3 General rules for address manipulation 3287 * When building TLV parameters for the ASCONF Chunk that will add or 3288 * delete IP addresses the D0 to D13 rules should be applied: 3289 */ 3290 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3291 const struct sctp_association *asoc, 3292 const sctp_subtype_t type, void *arg, 3293 sctp_cmd_seq_t *commands) 3294 { 3295 struct sctp_chunk *asconf_ack = arg; 3296 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3297 struct sctp_chunk *abort; 3298 sctp_addiphdr_t *addip_hdr; 3299 __u32 sent_serial, rcvd_serial; 3300 3301 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3302 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3303 SCTP_NULL()); 3304 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3305 } 3306 3307 /* Make sure that the ADDIP chunk has a valid length. */ 3308 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3309 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3310 commands); 3311 3312 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3313 rcvd_serial = ntohl(addip_hdr->serial); 3314 3315 if (last_asconf) { 3316 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3317 sent_serial = ntohl(addip_hdr->serial); 3318 } else { 3319 sent_serial = asoc->addip_serial - 1; 3320 } 3321 3322 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3323 * equal to the next serial number to be used but no ASCONF chunk is 3324 * outstanding the endpoint MUST ABORT the association. Note that a 3325 * sequence number is greater than if it is no more than 2^^31-1 3326 * larger than the current sequence number (using serial arithmetic). 3327 */ 3328 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3329 !(asoc->addip_last_asconf)) { 3330 abort = sctp_make_abort(asoc, asconf_ack, 3331 sizeof(sctp_errhdr_t)); 3332 if (abort) { 3333 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, NULL, 0); 3334 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3335 SCTP_CHUNK(abort)); 3336 } 3337 /* We are going to ABORT, so we might as well stop 3338 * processing the rest of the chunks in the packet. 3339 */ 3340 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3341 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3342 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3343 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3344 SCTP_U32(SCTP_ERROR_ASCONF_ACK)); 3345 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3346 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3347 return SCTP_DISPOSITION_ABORT; 3348 } 3349 3350 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3351 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3352 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3353 3354 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3355 asconf_ack)) 3356 return SCTP_DISPOSITION_CONSUME; 3357 3358 abort = sctp_make_abort(asoc, asconf_ack, 3359 sizeof(sctp_errhdr_t)); 3360 if (abort) { 3361 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, NULL, 0); 3362 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3363 SCTP_CHUNK(abort)); 3364 } 3365 /* We are going to ABORT, so we might as well stop 3366 * processing the rest of the chunks in the packet. 3367 */ 3368 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3369 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3370 SCTP_U32(SCTP_ERROR_ASCONF_ACK)); 3371 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3372 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3373 return SCTP_DISPOSITION_ABORT; 3374 } 3375 3376 return SCTP_DISPOSITION_DISCARD; 3377 } 3378 3379 /* 3380 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3381 * 3382 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3383 * its cumulative TSN point to the value carried in the FORWARD TSN 3384 * chunk, and then MUST further advance its cumulative TSN point locally 3385 * if possible. 3386 * After the above processing, the data receiver MUST stop reporting any 3387 * missing TSNs earlier than or equal to the new cumulative TSN point. 3388 * 3389 * Verification Tag: 8.5 Verification Tag [Normal verification] 3390 * 3391 * The return value is the disposition of the chunk. 3392 */ 3393 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3394 const struct sctp_association *asoc, 3395 const sctp_subtype_t type, 3396 void *arg, 3397 sctp_cmd_seq_t *commands) 3398 { 3399 struct sctp_chunk *chunk = arg; 3400 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3401 __u16 len; 3402 __u32 tsn; 3403 3404 if (!sctp_vtag_verify(chunk, asoc)) { 3405 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3406 SCTP_NULL()); 3407 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3408 } 3409 3410 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3411 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3412 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3413 commands); 3414 3415 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3416 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3417 len = ntohs(chunk->chunk_hdr->length); 3418 len -= sizeof(struct sctp_chunkhdr); 3419 skb_pull(chunk->skb, len); 3420 3421 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3422 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3423 3424 /* The TSN is too high--silently discard the chunk and count on it 3425 * getting retransmitted later. 3426 */ 3427 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3428 goto discard_noforce; 3429 3430 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3431 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3432 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3433 SCTP_CHUNK(chunk)); 3434 3435 /* Count this as receiving DATA. */ 3436 if (asoc->autoclose) { 3437 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3438 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3439 } 3440 3441 /* FIXME: For now send a SACK, but DATA processing may 3442 * send another. 3443 */ 3444 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3445 /* Start the SACK timer. */ 3446 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3447 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 3448 3449 return SCTP_DISPOSITION_CONSUME; 3450 3451 discard_noforce: 3452 return SCTP_DISPOSITION_DISCARD; 3453 } 3454 3455 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3456 const struct sctp_endpoint *ep, 3457 const struct sctp_association *asoc, 3458 const sctp_subtype_t type, 3459 void *arg, 3460 sctp_cmd_seq_t *commands) 3461 { 3462 struct sctp_chunk *chunk = arg; 3463 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3464 __u16 len; 3465 __u32 tsn; 3466 3467 if (!sctp_vtag_verify(chunk, asoc)) { 3468 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3469 SCTP_NULL()); 3470 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3471 } 3472 3473 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3474 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3475 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3476 commands); 3477 3478 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3479 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3480 len = ntohs(chunk->chunk_hdr->length); 3481 len -= sizeof(struct sctp_chunkhdr); 3482 skb_pull(chunk->skb, len); 3483 3484 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3485 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3486 3487 /* The TSN is too high--silently discard the chunk and count on it 3488 * getting retransmitted later. 3489 */ 3490 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3491 goto gen_shutdown; 3492 3493 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3494 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3495 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3496 SCTP_CHUNK(chunk)); 3497 3498 /* Go a head and force a SACK, since we are shutting down. */ 3499 gen_shutdown: 3500 /* Implementor's Guide. 3501 * 3502 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3503 * respond to each received packet containing one or more DATA chunk(s) 3504 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3505 */ 3506 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3507 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3508 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3509 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3510 3511 return SCTP_DISPOSITION_CONSUME; 3512 } 3513 3514 /* 3515 * Process an unknown chunk. 3516 * 3517 * Section: 3.2. Also, 2.1 in the implementor's guide. 3518 * 3519 * Chunk Types are encoded such that the highest-order two bits specify 3520 * the action that must be taken if the processing endpoint does not 3521 * recognize the Chunk Type. 3522 * 3523 * 00 - Stop processing this SCTP packet and discard it, do not process 3524 * any further chunks within it. 3525 * 3526 * 01 - Stop processing this SCTP packet and discard it, do not process 3527 * any further chunks within it, and report the unrecognized 3528 * chunk in an 'Unrecognized Chunk Type'. 3529 * 3530 * 10 - Skip this chunk and continue processing. 3531 * 3532 * 11 - Skip this chunk and continue processing, but report in an ERROR 3533 * Chunk using the 'Unrecognized Chunk Type' cause of error. 3534 * 3535 * The return value is the disposition of the chunk. 3536 */ 3537 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 3538 const struct sctp_association *asoc, 3539 const sctp_subtype_t type, 3540 void *arg, 3541 sctp_cmd_seq_t *commands) 3542 { 3543 struct sctp_chunk *unk_chunk = arg; 3544 struct sctp_chunk *err_chunk; 3545 sctp_chunkhdr_t *hdr; 3546 3547 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 3548 3549 if (!sctp_vtag_verify(unk_chunk, asoc)) 3550 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3551 3552 /* Make sure that the chunk has a valid length. 3553 * Since we don't know the chunk type, we use a general 3554 * chunkhdr structure to make a comparison. 3555 */ 3556 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 3557 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3558 commands); 3559 3560 switch (type.chunk & SCTP_CID_ACTION_MASK) { 3561 case SCTP_CID_ACTION_DISCARD: 3562 /* Discard the packet. */ 3563 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3564 break; 3565 case SCTP_CID_ACTION_DISCARD_ERR: 3566 /* Discard the packet. */ 3567 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3568 3569 /* Generate an ERROR chunk as response. */ 3570 hdr = unk_chunk->chunk_hdr; 3571 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3572 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3573 WORD_ROUND(ntohs(hdr->length))); 3574 if (err_chunk) { 3575 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3576 SCTP_CHUNK(err_chunk)); 3577 } 3578 return SCTP_DISPOSITION_CONSUME; 3579 break; 3580 case SCTP_CID_ACTION_SKIP: 3581 /* Skip the chunk. */ 3582 return SCTP_DISPOSITION_DISCARD; 3583 break; 3584 case SCTP_CID_ACTION_SKIP_ERR: 3585 /* Generate an ERROR chunk as response. */ 3586 hdr = unk_chunk->chunk_hdr; 3587 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3588 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3589 WORD_ROUND(ntohs(hdr->length))); 3590 if (err_chunk) { 3591 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3592 SCTP_CHUNK(err_chunk)); 3593 } 3594 /* Skip the chunk. */ 3595 return SCTP_DISPOSITION_CONSUME; 3596 break; 3597 default: 3598 break; 3599 } 3600 3601 return SCTP_DISPOSITION_DISCARD; 3602 } 3603 3604 /* 3605 * Discard the chunk. 3606 * 3607 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 3608 * [Too numerous to mention...] 3609 * Verification Tag: No verification needed. 3610 * Inputs 3611 * (endpoint, asoc, chunk) 3612 * 3613 * Outputs 3614 * (asoc, reply_msg, msg_up, timers, counters) 3615 * 3616 * The return value is the disposition of the chunk. 3617 */ 3618 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 3619 const struct sctp_association *asoc, 3620 const sctp_subtype_t type, 3621 void *arg, 3622 sctp_cmd_seq_t *commands) 3623 { 3624 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 3625 return SCTP_DISPOSITION_DISCARD; 3626 } 3627 3628 /* 3629 * Discard the whole packet. 3630 * 3631 * Section: 8.4 2) 3632 * 3633 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 3634 * silently discard the OOTB packet and take no further action. 3635 * 3636 * Verification Tag: No verification necessary 3637 * 3638 * Inputs 3639 * (endpoint, asoc, chunk) 3640 * 3641 * Outputs 3642 * (asoc, reply_msg, msg_up, timers, counters) 3643 * 3644 * The return value is the disposition of the chunk. 3645 */ 3646 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 3647 const struct sctp_association *asoc, 3648 const sctp_subtype_t type, 3649 void *arg, 3650 sctp_cmd_seq_t *commands) 3651 { 3652 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3653 3654 return SCTP_DISPOSITION_CONSUME; 3655 } 3656 3657 3658 /* 3659 * The other end is violating protocol. 3660 * 3661 * Section: Not specified 3662 * Verification Tag: Not specified 3663 * Inputs 3664 * (endpoint, asoc, chunk) 3665 * 3666 * Outputs 3667 * (asoc, reply_msg, msg_up, timers, counters) 3668 * 3669 * We simply tag the chunk as a violation. The state machine will log 3670 * the violation and continue. 3671 */ 3672 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 3673 const struct sctp_association *asoc, 3674 const sctp_subtype_t type, 3675 void *arg, 3676 sctp_cmd_seq_t *commands) 3677 { 3678 return SCTP_DISPOSITION_VIOLATION; 3679 } 3680 3681 3682 /* 3683 * Handle a protocol violation when the chunk length is invalid. 3684 * "Invalid" length is identified as smaller then the minimal length a 3685 * given chunk can be. For example, a SACK chunk has invalid length 3686 * if it's length is set to be smaller then the size of sctp_sack_chunk_t. 3687 * 3688 * We inform the other end by sending an ABORT with a Protocol Violation 3689 * error code. 3690 * 3691 * Section: Not specified 3692 * Verification Tag: Nothing to do 3693 * Inputs 3694 * (endpoint, asoc, chunk) 3695 * 3696 * Outputs 3697 * (reply_msg, msg_up, counters) 3698 * 3699 * Generate an ABORT chunk and terminate the association. 3700 */ 3701 static sctp_disposition_t sctp_sf_violation_chunklen( 3702 const struct sctp_endpoint *ep, 3703 const struct sctp_association *asoc, 3704 const sctp_subtype_t type, 3705 void *arg, 3706 sctp_cmd_seq_t *commands) 3707 { 3708 struct sctp_chunk *chunk = arg; 3709 struct sctp_chunk *abort = NULL; 3710 char err_str[]="The following chunk had invalid length:"; 3711 3712 /* Make the abort chunk. */ 3713 abort = sctp_make_abort_violation(asoc, chunk, err_str, 3714 sizeof(err_str)); 3715 if (!abort) 3716 goto nomem; 3717 3718 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 3719 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3720 3721 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 3722 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3723 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 3724 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 3725 SCTP_U32(SCTP_ERROR_PROTO_VIOLATION)); 3726 } else { 3727 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3728 SCTP_U32(SCTP_ERROR_PROTO_VIOLATION)); 3729 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3730 } 3731 3732 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3733 3734 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3735 3736 return SCTP_DISPOSITION_ABORT; 3737 3738 nomem: 3739 return SCTP_DISPOSITION_NOMEM; 3740 } 3741 3742 /*************************************************************************** 3743 * These are the state functions for handling primitive (Section 10) events. 3744 ***************************************************************************/ 3745 /* 3746 * sctp_sf_do_prm_asoc 3747 * 3748 * Section: 10.1 ULP-to-SCTP 3749 * B) Associate 3750 * 3751 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 3752 * outbound stream count) 3753 * -> association id [,destination transport addr list] [,outbound stream 3754 * count] 3755 * 3756 * This primitive allows the upper layer to initiate an association to a 3757 * specific peer endpoint. 3758 * 3759 * The peer endpoint shall be specified by one of the transport addresses 3760 * which defines the endpoint (see Section 1.4). If the local SCTP 3761 * instance has not been initialized, the ASSOCIATE is considered an 3762 * error. 3763 * [This is not relevant for the kernel implementation since we do all 3764 * initialization at boot time. It we hadn't initialized we wouldn't 3765 * get anywhere near this code.] 3766 * 3767 * An association id, which is a local handle to the SCTP association, 3768 * will be returned on successful establishment of the association. If 3769 * SCTP is not able to open an SCTP association with the peer endpoint, 3770 * an error is returned. 3771 * [In the kernel implementation, the struct sctp_association needs to 3772 * be created BEFORE causing this primitive to run.] 3773 * 3774 * Other association parameters may be returned, including the 3775 * complete destination transport addresses of the peer as well as the 3776 * outbound stream count of the local endpoint. One of the transport 3777 * address from the returned destination addresses will be selected by 3778 * the local endpoint as default primary path for sending SCTP packets 3779 * to this peer. The returned "destination transport addr list" can 3780 * be used by the ULP to change the default primary path or to force 3781 * sending a packet to a specific transport address. [All of this 3782 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 3783 * function.] 3784 * 3785 * Mandatory attributes: 3786 * 3787 * o local SCTP instance name - obtained from the INITIALIZE operation. 3788 * [This is the argument asoc.] 3789 * o destination transport addr - specified as one of the transport 3790 * addresses of the peer endpoint with which the association is to be 3791 * established. 3792 * [This is asoc->peer.active_path.] 3793 * o outbound stream count - the number of outbound streams the ULP 3794 * would like to open towards this peer endpoint. 3795 * [BUG: This is not currently implemented.] 3796 * Optional attributes: 3797 * 3798 * None. 3799 * 3800 * The return value is a disposition. 3801 */ 3802 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 3803 const struct sctp_association *asoc, 3804 const sctp_subtype_t type, 3805 void *arg, 3806 sctp_cmd_seq_t *commands) 3807 { 3808 struct sctp_chunk *repl; 3809 3810 /* The comment below says that we enter COOKIE-WAIT AFTER 3811 * sending the INIT, but that doesn't actually work in our 3812 * implementation... 3813 */ 3814 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3815 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 3816 3817 /* RFC 2960 5.1 Normal Establishment of an Association 3818 * 3819 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 3820 * must provide its Verification Tag (Tag_A) in the Initiate 3821 * Tag field. Tag_A SHOULD be a random number in the range of 3822 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 3823 */ 3824 3825 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 3826 if (!repl) 3827 goto nomem; 3828 3829 /* Cast away the const modifier, as we want to just 3830 * rerun it through as a sideffect. 3831 */ 3832 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, 3833 SCTP_ASOC((struct sctp_association *) asoc)); 3834 3835 /* Choose transport for INIT. */ 3836 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 3837 SCTP_CHUNK(repl)); 3838 3839 /* After sending the INIT, "A" starts the T1-init timer and 3840 * enters the COOKIE-WAIT state. 3841 */ 3842 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 3843 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 3844 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 3845 return SCTP_DISPOSITION_CONSUME; 3846 3847 nomem: 3848 return SCTP_DISPOSITION_NOMEM; 3849 } 3850 3851 /* 3852 * Process the SEND primitive. 3853 * 3854 * Section: 10.1 ULP-to-SCTP 3855 * E) Send 3856 * 3857 * Format: SEND(association id, buffer address, byte count [,context] 3858 * [,stream id] [,life time] [,destination transport address] 3859 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 3860 * -> result 3861 * 3862 * This is the main method to send user data via SCTP. 3863 * 3864 * Mandatory attributes: 3865 * 3866 * o association id - local handle to the SCTP association 3867 * 3868 * o buffer address - the location where the user message to be 3869 * transmitted is stored; 3870 * 3871 * o byte count - The size of the user data in number of bytes; 3872 * 3873 * Optional attributes: 3874 * 3875 * o context - an optional 32 bit integer that will be carried in the 3876 * sending failure notification to the ULP if the transportation of 3877 * this User Message fails. 3878 * 3879 * o stream id - to indicate which stream to send the data on. If not 3880 * specified, stream 0 will be used. 3881 * 3882 * o life time - specifies the life time of the user data. The user data 3883 * will not be sent by SCTP after the life time expires. This 3884 * parameter can be used to avoid efforts to transmit stale 3885 * user messages. SCTP notifies the ULP if the data cannot be 3886 * initiated to transport (i.e. sent to the destination via SCTP's 3887 * send primitive) within the life time variable. However, the 3888 * user data will be transmitted if SCTP has attempted to transmit a 3889 * chunk before the life time expired. 3890 * 3891 * o destination transport address - specified as one of the destination 3892 * transport addresses of the peer endpoint to which this packet 3893 * should be sent. Whenever possible, SCTP should use this destination 3894 * transport address for sending the packets, instead of the current 3895 * primary path. 3896 * 3897 * o unorder flag - this flag, if present, indicates that the user 3898 * would like the data delivered in an unordered fashion to the peer 3899 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 3900 * message). 3901 * 3902 * o no-bundle flag - instructs SCTP not to bundle this user data with 3903 * other outbound DATA chunks. SCTP MAY still bundle even when 3904 * this flag is present, when faced with network congestion. 3905 * 3906 * o payload protocol-id - A 32 bit unsigned integer that is to be 3907 * passed to the peer indicating the type of payload protocol data 3908 * being transmitted. This value is passed as opaque data by SCTP. 3909 * 3910 * The return value is the disposition. 3911 */ 3912 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 3913 const struct sctp_association *asoc, 3914 const sctp_subtype_t type, 3915 void *arg, 3916 sctp_cmd_seq_t *commands) 3917 { 3918 struct sctp_chunk *chunk = arg; 3919 3920 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 3921 return SCTP_DISPOSITION_CONSUME; 3922 } 3923 3924 /* 3925 * Process the SHUTDOWN primitive. 3926 * 3927 * Section: 10.1: 3928 * C) Shutdown 3929 * 3930 * Format: SHUTDOWN(association id) 3931 * -> result 3932 * 3933 * Gracefully closes an association. Any locally queued user data 3934 * will be delivered to the peer. The association will be terminated only 3935 * after the peer acknowledges all the SCTP packets sent. A success code 3936 * will be returned on successful termination of the association. If 3937 * attempting to terminate the association results in a failure, an error 3938 * code shall be returned. 3939 * 3940 * Mandatory attributes: 3941 * 3942 * o association id - local handle to the SCTP association 3943 * 3944 * Optional attributes: 3945 * 3946 * None. 3947 * 3948 * The return value is the disposition. 3949 */ 3950 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 3951 const struct sctp_endpoint *ep, 3952 const struct sctp_association *asoc, 3953 const sctp_subtype_t type, 3954 void *arg, 3955 sctp_cmd_seq_t *commands) 3956 { 3957 int disposition; 3958 3959 /* From 9.2 Shutdown of an Association 3960 * Upon receipt of the SHUTDOWN primitive from its upper 3961 * layer, the endpoint enters SHUTDOWN-PENDING state and 3962 * remains there until all outstanding data has been 3963 * acknowledged by its peer. The endpoint accepts no new data 3964 * from its upper layer, but retransmits data to the far end 3965 * if necessary to fill gaps. 3966 */ 3967 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3968 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 3969 3970 /* sctpimpguide-05 Section 2.12.2 3971 * The sender of the SHUTDOWN MAY also start an overall guard timer 3972 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 3973 */ 3974 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 3975 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3976 3977 disposition = SCTP_DISPOSITION_CONSUME; 3978 if (sctp_outq_is_empty(&asoc->outqueue)) { 3979 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 3980 arg, commands); 3981 } 3982 return disposition; 3983 } 3984 3985 /* 3986 * Process the ABORT primitive. 3987 * 3988 * Section: 10.1: 3989 * C) Abort 3990 * 3991 * Format: Abort(association id [, cause code]) 3992 * -> result 3993 * 3994 * Ungracefully closes an association. Any locally queued user data 3995 * will be discarded and an ABORT chunk is sent to the peer. A success code 3996 * will be returned on successful abortion of the association. If 3997 * attempting to abort the association results in a failure, an error 3998 * code shall be returned. 3999 * 4000 * Mandatory attributes: 4001 * 4002 * o association id - local handle to the SCTP association 4003 * 4004 * Optional attributes: 4005 * 4006 * o cause code - reason of the abort to be passed to the peer 4007 * 4008 * None. 4009 * 4010 * The return value is the disposition. 4011 */ 4012 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4013 const struct sctp_endpoint *ep, 4014 const struct sctp_association *asoc, 4015 const sctp_subtype_t type, 4016 void *arg, 4017 sctp_cmd_seq_t *commands) 4018 { 4019 /* From 9.1 Abort of an Association 4020 * Upon receipt of the ABORT primitive from its upper 4021 * layer, the endpoint enters CLOSED state and 4022 * discard all outstanding data has been 4023 * acknowledged by its peer. The endpoint accepts no new data 4024 * from its upper layer, but retransmits data to the far end 4025 * if necessary to fill gaps. 4026 */ 4027 struct msghdr *msg = arg; 4028 struct sctp_chunk *abort; 4029 sctp_disposition_t retval; 4030 4031 retval = SCTP_DISPOSITION_CONSUME; 4032 4033 /* Generate ABORT chunk to send the peer. */ 4034 abort = sctp_make_abort_user(asoc, NULL, msg); 4035 if (!abort) 4036 retval = SCTP_DISPOSITION_NOMEM; 4037 else 4038 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4039 4040 /* Even if we can't send the ABORT due to low memory delete the 4041 * TCB. This is a departure from our typical NOMEM handling. 4042 */ 4043 4044 /* Delete the established association. */ 4045 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4046 SCTP_U32(SCTP_ERROR_USER_ABORT)); 4047 4048 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4049 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4050 4051 return retval; 4052 } 4053 4054 /* We tried an illegal operation on an association which is closed. */ 4055 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4056 const struct sctp_association *asoc, 4057 const sctp_subtype_t type, 4058 void *arg, 4059 sctp_cmd_seq_t *commands) 4060 { 4061 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4062 return SCTP_DISPOSITION_CONSUME; 4063 } 4064 4065 /* We tried an illegal operation on an association which is shutting 4066 * down. 4067 */ 4068 sctp_disposition_t sctp_sf_error_shutdown(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, 4075 SCTP_ERROR(-ESHUTDOWN)); 4076 return SCTP_DISPOSITION_CONSUME; 4077 } 4078 4079 /* 4080 * sctp_cookie_wait_prm_shutdown 4081 * 4082 * Section: 4 Note: 2 4083 * Verification Tag: 4084 * Inputs 4085 * (endpoint, asoc) 4086 * 4087 * The RFC does not explicitly address this issue, but is the route through the 4088 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4089 * 4090 * Outputs 4091 * (timers) 4092 */ 4093 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4094 const struct sctp_endpoint *ep, 4095 const struct sctp_association *asoc, 4096 const sctp_subtype_t type, 4097 void *arg, 4098 sctp_cmd_seq_t *commands) 4099 { 4100 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4101 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4102 4103 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4104 SCTP_STATE(SCTP_STATE_CLOSED)); 4105 4106 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4107 4108 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4109 4110 return SCTP_DISPOSITION_DELETE_TCB; 4111 } 4112 4113 /* 4114 * sctp_cookie_echoed_prm_shutdown 4115 * 4116 * Section: 4 Note: 2 4117 * Verification Tag: 4118 * Inputs 4119 * (endpoint, asoc) 4120 * 4121 * The RFC does not explcitly address this issue, but is the route through the 4122 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4123 * 4124 * Outputs 4125 * (timers) 4126 */ 4127 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4128 const struct sctp_endpoint *ep, 4129 const struct sctp_association *asoc, 4130 const sctp_subtype_t type, 4131 void *arg, sctp_cmd_seq_t *commands) 4132 { 4133 /* There is a single T1 timer, so we should be able to use 4134 * common function with the COOKIE-WAIT state. 4135 */ 4136 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4137 } 4138 4139 /* 4140 * sctp_sf_cookie_wait_prm_abort 4141 * 4142 * Section: 4 Note: 2 4143 * Verification Tag: 4144 * Inputs 4145 * (endpoint, asoc) 4146 * 4147 * The RFC does not explicitly address this issue, but is the route through the 4148 * state table when someone issues an abort while in COOKIE_WAIT state. 4149 * 4150 * Outputs 4151 * (timers) 4152 */ 4153 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4154 const struct sctp_endpoint *ep, 4155 const struct sctp_association *asoc, 4156 const sctp_subtype_t type, 4157 void *arg, 4158 sctp_cmd_seq_t *commands) 4159 { 4160 struct msghdr *msg = arg; 4161 struct sctp_chunk *abort; 4162 sctp_disposition_t retval; 4163 4164 /* Stop T1-init timer */ 4165 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4166 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4167 retval = SCTP_DISPOSITION_CONSUME; 4168 4169 /* Generate ABORT chunk to send the peer */ 4170 abort = sctp_make_abort_user(asoc, NULL, msg); 4171 if (!abort) 4172 retval = SCTP_DISPOSITION_NOMEM; 4173 else 4174 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4175 4176 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4177 SCTP_STATE(SCTP_STATE_CLOSED)); 4178 4179 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4180 4181 /* Even if we can't send the ABORT due to low memory delete the 4182 * TCB. This is a departure from our typical NOMEM handling. 4183 */ 4184 4185 /* Delete the established association. */ 4186 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4187 SCTP_U32(SCTP_ERROR_USER_ABORT)); 4188 4189 return retval; 4190 } 4191 4192 /* 4193 * sctp_sf_cookie_echoed_prm_abort 4194 * 4195 * Section: 4 Note: 3 4196 * Verification Tag: 4197 * Inputs 4198 * (endpoint, asoc) 4199 * 4200 * The RFC does not explcitly address this issue, but is the route through the 4201 * state table when someone issues an abort while in COOKIE_ECHOED state. 4202 * 4203 * Outputs 4204 * (timers) 4205 */ 4206 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4207 const struct sctp_endpoint *ep, 4208 const struct sctp_association *asoc, 4209 const sctp_subtype_t type, 4210 void *arg, 4211 sctp_cmd_seq_t *commands) 4212 { 4213 /* There is a single T1 timer, so we should be able to use 4214 * common function with the COOKIE-WAIT state. 4215 */ 4216 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4217 } 4218 4219 /* 4220 * sctp_sf_shutdown_pending_prm_abort 4221 * 4222 * Inputs 4223 * (endpoint, asoc) 4224 * 4225 * The RFC does not explicitly address this issue, but is the route through the 4226 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4227 * 4228 * Outputs 4229 * (timers) 4230 */ 4231 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4232 const struct sctp_endpoint *ep, 4233 const struct sctp_association *asoc, 4234 const sctp_subtype_t type, 4235 void *arg, 4236 sctp_cmd_seq_t *commands) 4237 { 4238 /* Stop the T5-shutdown guard timer. */ 4239 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4240 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4241 4242 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4243 } 4244 4245 /* 4246 * sctp_sf_shutdown_sent_prm_abort 4247 * 4248 * Inputs 4249 * (endpoint, asoc) 4250 * 4251 * The RFC does not explicitly address this issue, but is the route through the 4252 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4253 * 4254 * Outputs 4255 * (timers) 4256 */ 4257 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4258 const struct sctp_endpoint *ep, 4259 const struct sctp_association *asoc, 4260 const sctp_subtype_t type, 4261 void *arg, 4262 sctp_cmd_seq_t *commands) 4263 { 4264 /* Stop the T2-shutdown timer. */ 4265 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4266 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4267 4268 /* Stop the T5-shutdown guard timer. */ 4269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4270 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4271 4272 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4273 } 4274 4275 /* 4276 * sctp_sf_cookie_echoed_prm_abort 4277 * 4278 * Inputs 4279 * (endpoint, asoc) 4280 * 4281 * The RFC does not explcitly address this issue, but is the route through the 4282 * state table when someone issues an abort while in COOKIE_ECHOED state. 4283 * 4284 * Outputs 4285 * (timers) 4286 */ 4287 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4288 const struct sctp_endpoint *ep, 4289 const struct sctp_association *asoc, 4290 const sctp_subtype_t type, 4291 void *arg, 4292 sctp_cmd_seq_t *commands) 4293 { 4294 /* The same T2 timer, so we should be able to use 4295 * common function with the SHUTDOWN-SENT state. 4296 */ 4297 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4298 } 4299 4300 /* 4301 * Process the REQUESTHEARTBEAT primitive 4302 * 4303 * 10.1 ULP-to-SCTP 4304 * J) Request Heartbeat 4305 * 4306 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4307 * 4308 * -> result 4309 * 4310 * Instructs the local endpoint to perform a HeartBeat on the specified 4311 * destination transport address of the given association. The returned 4312 * result should indicate whether the transmission of the HEARTBEAT 4313 * chunk to the destination address is successful. 4314 * 4315 * Mandatory attributes: 4316 * 4317 * o association id - local handle to the SCTP association 4318 * 4319 * o destination transport address - the transport address of the 4320 * association on which a heartbeat should be issued. 4321 */ 4322 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4323 const struct sctp_endpoint *ep, 4324 const struct sctp_association *asoc, 4325 const sctp_subtype_t type, 4326 void *arg, 4327 sctp_cmd_seq_t *commands) 4328 { 4329 return sctp_sf_heartbeat(ep, asoc, type, (struct sctp_transport *)arg, 4330 commands); 4331 } 4332 4333 /* 4334 * ADDIP Section 4.1 ASCONF Chunk Procedures 4335 * When an endpoint has an ASCONF signaled change to be sent to the 4336 * remote endpoint it should do A1 to A9 4337 */ 4338 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 4339 const struct sctp_association *asoc, 4340 const sctp_subtype_t type, 4341 void *arg, 4342 sctp_cmd_seq_t *commands) 4343 { 4344 struct sctp_chunk *chunk = arg; 4345 4346 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4347 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4348 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4349 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4350 return SCTP_DISPOSITION_CONSUME; 4351 } 4352 4353 /* 4354 * Ignore the primitive event 4355 * 4356 * The return value is the disposition of the primitive. 4357 */ 4358 sctp_disposition_t sctp_sf_ignore_primitive( 4359 const struct sctp_endpoint *ep, 4360 const struct sctp_association *asoc, 4361 const sctp_subtype_t type, 4362 void *arg, 4363 sctp_cmd_seq_t *commands) 4364 { 4365 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 4366 return SCTP_DISPOSITION_DISCARD; 4367 } 4368 4369 /*************************************************************************** 4370 * These are the state functions for the OTHER events. 4371 ***************************************************************************/ 4372 4373 /* 4374 * Start the shutdown negotiation. 4375 * 4376 * From Section 9.2: 4377 * Once all its outstanding data has been acknowledged, the endpoint 4378 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 4379 * TSN Ack field the last sequential TSN it has received from the peer. 4380 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 4381 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 4382 * with the updated last sequential TSN received from its peer. 4383 * 4384 * The return value is the disposition. 4385 */ 4386 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 4387 const struct sctp_endpoint *ep, 4388 const struct sctp_association *asoc, 4389 const sctp_subtype_t type, 4390 void *arg, 4391 sctp_cmd_seq_t *commands) 4392 { 4393 struct sctp_chunk *reply; 4394 4395 /* Once all its outstanding data has been acknowledged, the 4396 * endpoint shall send a SHUTDOWN chunk to its peer including 4397 * in the Cumulative TSN Ack field the last sequential TSN it 4398 * has received from the peer. 4399 */ 4400 reply = sctp_make_shutdown(asoc, NULL); 4401 if (!reply) 4402 goto nomem; 4403 4404 /* Set the transport for the SHUTDOWN chunk and the timeout for the 4405 * T2-shutdown timer. 4406 */ 4407 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4408 4409 /* It shall then start the T2-shutdown timer */ 4410 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4411 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4412 4413 if (asoc->autoclose) 4414 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4415 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4416 4417 /* and enter the SHUTDOWN-SENT state. */ 4418 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4419 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 4420 4421 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4422 * 4423 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4424 * or SHUTDOWN-ACK. 4425 */ 4426 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4427 4428 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4429 4430 return SCTP_DISPOSITION_CONSUME; 4431 4432 nomem: 4433 return SCTP_DISPOSITION_NOMEM; 4434 } 4435 4436 /* 4437 * Generate a SHUTDOWN ACK now that everything is SACK'd. 4438 * 4439 * From Section 9.2: 4440 * 4441 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4442 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 4443 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 4444 * endpoint must re-send the SHUTDOWN ACK. 4445 * 4446 * The return value is the disposition. 4447 */ 4448 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 4449 const struct sctp_endpoint *ep, 4450 const struct sctp_association *asoc, 4451 const sctp_subtype_t type, 4452 void *arg, 4453 sctp_cmd_seq_t *commands) 4454 { 4455 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 4456 struct sctp_chunk *reply; 4457 4458 /* There are 2 ways of getting here: 4459 * 1) called in response to a SHUTDOWN chunk 4460 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 4461 * 4462 * For the case (2), the arg parameter is set to NULL. We need 4463 * to check that we have a chunk before accessing it's fields. 4464 */ 4465 if (chunk) { 4466 if (!sctp_vtag_verify(chunk, asoc)) 4467 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4468 4469 /* Make sure that the SHUTDOWN chunk has a valid length. */ 4470 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 4471 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4472 commands); 4473 } 4474 4475 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4476 * shall send a SHUTDOWN ACK ... 4477 */ 4478 reply = sctp_make_shutdown_ack(asoc, chunk); 4479 if (!reply) 4480 goto nomem; 4481 4482 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 4483 * the T2-shutdown timer. 4484 */ 4485 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4486 4487 /* and start/restart a T2-shutdown timer of its own, */ 4488 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4489 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4490 4491 if (asoc->autoclose) 4492 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4493 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4494 4495 /* Enter the SHUTDOWN-ACK-SENT state. */ 4496 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4497 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 4498 4499 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4500 * 4501 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4502 * or SHUTDOWN-ACK. 4503 */ 4504 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4505 4506 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4507 4508 return SCTP_DISPOSITION_CONSUME; 4509 4510 nomem: 4511 return SCTP_DISPOSITION_NOMEM; 4512 } 4513 4514 /* 4515 * Ignore the event defined as other 4516 * 4517 * The return value is the disposition of the event. 4518 */ 4519 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 4520 const struct sctp_association *asoc, 4521 const sctp_subtype_t type, 4522 void *arg, 4523 sctp_cmd_seq_t *commands) 4524 { 4525 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 4526 return SCTP_DISPOSITION_DISCARD; 4527 } 4528 4529 /************************************************************ 4530 * These are the state functions for handling timeout events. 4531 ************************************************************/ 4532 4533 /* 4534 * RTX Timeout 4535 * 4536 * Section: 6.3.3 Handle T3-rtx Expiration 4537 * 4538 * Whenever the retransmission timer T3-rtx expires for a destination 4539 * address, do the following: 4540 * [See below] 4541 * 4542 * The return value is the disposition of the chunk. 4543 */ 4544 sctp_disposition_t sctp_sf_do_6_3_3_rtx(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 struct sctp_transport *transport = arg; 4551 4552 if (asoc->overall_error_count >= asoc->max_retrans) { 4553 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 4554 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4555 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4556 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4557 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4558 return SCTP_DISPOSITION_DELETE_TCB; 4559 } 4560 4561 /* E1) For the destination address for which the timer 4562 * expires, adjust its ssthresh with rules defined in Section 4563 * 7.2.3 and set the cwnd <- MTU. 4564 */ 4565 4566 /* E2) For the destination address for which the timer 4567 * expires, set RTO <- RTO * 2 ("back off the timer"). The 4568 * maximum value discussed in rule C7 above (RTO.max) may be 4569 * used to provide an upper bound to this doubling operation. 4570 */ 4571 4572 /* E3) Determine how many of the earliest (i.e., lowest TSN) 4573 * outstanding DATA chunks for the address for which the 4574 * T3-rtx has expired will fit into a single packet, subject 4575 * to the MTU constraint for the path corresponding to the 4576 * destination transport address to which the retransmission 4577 * is being sent (this may be different from the address for 4578 * which the timer expires [see Section 6.4]). Call this 4579 * value K. Bundle and retransmit those K DATA chunks in a 4580 * single packet to the destination endpoint. 4581 * 4582 * Note: Any DATA chunks that were sent to the address for 4583 * which the T3-rtx timer expired but did not fit in one MTU 4584 * (rule E3 above), should be marked for retransmission and 4585 * sent as soon as cwnd allows (normally when a SACK arrives). 4586 */ 4587 4588 /* NB: Rules E4 and F1 are implicit in R1. */ 4589 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 4590 4591 /* Do some failure management (Section 8.2). */ 4592 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 4593 4594 return SCTP_DISPOSITION_CONSUME; 4595 } 4596 4597 /* 4598 * Generate delayed SACK on timeout 4599 * 4600 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 4601 * 4602 * The guidelines on delayed acknowledgement algorithm specified in 4603 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 4604 * acknowledgement SHOULD be generated for at least every second packet 4605 * (not every second DATA chunk) received, and SHOULD be generated 4606 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 4607 * some situations it may be beneficial for an SCTP transmitter to be 4608 * more conservative than the algorithms detailed in this document 4609 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 4610 * the following algorithms allow. 4611 */ 4612 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 4613 const struct sctp_association *asoc, 4614 const sctp_subtype_t type, 4615 void *arg, 4616 sctp_cmd_seq_t *commands) 4617 { 4618 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4619 return SCTP_DISPOSITION_CONSUME; 4620 } 4621 4622 /* 4623 * sctp_sf_t1_init_timer_expire 4624 * 4625 * Section: 4 Note: 2 4626 * Verification Tag: 4627 * Inputs 4628 * (endpoint, asoc) 4629 * 4630 * RFC 2960 Section 4 Notes 4631 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 4632 * and re-start the T1-init timer without changing state. This MUST 4633 * be repeated up to 'Max.Init.Retransmits' times. After that, the 4634 * endpoint MUST abort the initialization process and report the 4635 * error to SCTP user. 4636 * 4637 * Outputs 4638 * (timers, events) 4639 * 4640 */ 4641 sctp_disposition_t sctp_sf_t1_init_timer_expire(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 struct sctp_chunk *repl = NULL; 4648 struct sctp_bind_addr *bp; 4649 int attempts = asoc->init_err_counter + 1; 4650 4651 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 4652 4653 if (attempts < asoc->max_init_attempts) { 4654 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 4655 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 4656 if (!repl) 4657 return SCTP_DISPOSITION_NOMEM; 4658 4659 /* Choose transport for INIT. */ 4660 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4661 SCTP_CHUNK(repl)); 4662 4663 /* Issue a sideeffect to do the needed accounting. */ 4664 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 4665 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4666 4667 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4668 } else { 4669 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 4670 " max_init_attempts: %d\n", 4671 attempts, asoc->max_init_attempts); 4672 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4673 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4674 return SCTP_DISPOSITION_DELETE_TCB; 4675 } 4676 4677 return SCTP_DISPOSITION_CONSUME; 4678 } 4679 4680 /* 4681 * sctp_sf_t1_cookie_timer_expire 4682 * 4683 * Section: 4 Note: 2 4684 * Verification Tag: 4685 * Inputs 4686 * (endpoint, asoc) 4687 * 4688 * RFC 2960 Section 4 Notes 4689 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 4690 * COOKIE ECHO and re-start the T1-cookie timer without changing 4691 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 4692 * After that, the endpoint MUST abort the initialization process and 4693 * report the error to SCTP user. 4694 * 4695 * Outputs 4696 * (timers, events) 4697 * 4698 */ 4699 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 4700 const struct sctp_association *asoc, 4701 const sctp_subtype_t type, 4702 void *arg, 4703 sctp_cmd_seq_t *commands) 4704 { 4705 struct sctp_chunk *repl = NULL; 4706 int attempts = asoc->init_err_counter + 1; 4707 4708 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 4709 4710 if (attempts < asoc->max_init_attempts) { 4711 repl = sctp_make_cookie_echo(asoc, NULL); 4712 if (!repl) 4713 return SCTP_DISPOSITION_NOMEM; 4714 4715 /* Issue a sideeffect to do the needed accounting. */ 4716 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 4717 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 4718 4719 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4720 } else { 4721 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4722 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4723 return SCTP_DISPOSITION_DELETE_TCB; 4724 } 4725 4726 return SCTP_DISPOSITION_CONSUME; 4727 } 4728 4729 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 4730 * with the updated last sequential TSN received from its peer. 4731 * 4732 * An endpoint should limit the number of retransmissions of the 4733 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 4734 * If this threshold is exceeded the endpoint should destroy the TCB and 4735 * MUST report the peer endpoint unreachable to the upper layer (and 4736 * thus the association enters the CLOSED state). The reception of any 4737 * packet from its peer (i.e. as the peer sends all of its queued DATA 4738 * chunks) should clear the endpoint's retransmission count and restart 4739 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 4740 * all of its queued DATA chunks that have not yet been sent. 4741 */ 4742 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 4743 const struct sctp_association *asoc, 4744 const sctp_subtype_t type, 4745 void *arg, 4746 sctp_cmd_seq_t *commands) 4747 { 4748 struct sctp_chunk *reply = NULL; 4749 4750 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 4751 if (asoc->overall_error_count >= asoc->max_retrans) { 4752 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 4753 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4754 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4755 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4756 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4757 return SCTP_DISPOSITION_DELETE_TCB; 4758 } 4759 4760 switch (asoc->state) { 4761 case SCTP_STATE_SHUTDOWN_SENT: 4762 reply = sctp_make_shutdown(asoc, NULL); 4763 break; 4764 4765 case SCTP_STATE_SHUTDOWN_ACK_SENT: 4766 reply = sctp_make_shutdown_ack(asoc, NULL); 4767 break; 4768 4769 default: 4770 BUG(); 4771 break; 4772 }; 4773 4774 if (!reply) 4775 goto nomem; 4776 4777 /* Do some failure management (Section 8.2). */ 4778 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 4779 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 4780 4781 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 4782 * the T2-shutdown timer. 4783 */ 4784 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4785 4786 /* Restart the T2-shutdown timer. */ 4787 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4788 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4789 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4790 return SCTP_DISPOSITION_CONSUME; 4791 4792 nomem: 4793 return SCTP_DISPOSITION_NOMEM; 4794 } 4795 4796 /* 4797 * ADDIP Section 4.1 ASCONF CHunk Procedures 4798 * If the T4 RTO timer expires the endpoint should do B1 to B5 4799 */ 4800 sctp_disposition_t sctp_sf_t4_timer_expire( 4801 const struct sctp_endpoint *ep, 4802 const struct sctp_association *asoc, 4803 const sctp_subtype_t type, 4804 void *arg, 4805 sctp_cmd_seq_t *commands) 4806 { 4807 struct sctp_chunk *chunk = asoc->addip_last_asconf; 4808 struct sctp_transport *transport = chunk->transport; 4809 4810 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 4811 * detection on the appropriate destination address as defined in 4812 * RFC2960 [5] section 8.1 and 8.2. 4813 */ 4814 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 4815 4816 /* Reconfig T4 timer and transport. */ 4817 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4818 4819 /* ADDIP 4.1 B2) Increment the association error counters and perform 4820 * endpoint failure detection on the association as defined in 4821 * RFC2960 [5] section 8.1 and 8.2. 4822 * association error counter is incremented in SCTP_CMD_STRIKE. 4823 */ 4824 if (asoc->overall_error_count >= asoc->max_retrans) { 4825 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4826 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4827 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4828 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4829 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4830 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 4831 return SCTP_DISPOSITION_ABORT; 4832 } 4833 4834 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 4835 * the ASCONF chunk was sent by doubling the RTO timer value. 4836 * This is done in SCTP_CMD_STRIKE. 4837 */ 4838 4839 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 4840 * choose an alternate destination address (please refer to RFC2960 4841 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 4842 * chunk, it MUST be the same (including its serial number) as the last 4843 * ASCONF sent. 4844 */ 4845 sctp_chunk_hold(asoc->addip_last_asconf); 4846 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4847 SCTP_CHUNK(asoc->addip_last_asconf)); 4848 4849 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 4850 * destination is selected, then the RTO used will be that of the new 4851 * destination address. 4852 */ 4853 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4854 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4855 4856 return SCTP_DISPOSITION_CONSUME; 4857 } 4858 4859 /* sctpimpguide-05 Section 2.12.2 4860 * The sender of the SHUTDOWN MAY also start an overall guard timer 4861 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4862 * At the expiration of this timer the sender SHOULD abort the association 4863 * by sending an ABORT chunk. 4864 */ 4865 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 4866 const struct sctp_association *asoc, 4867 const sctp_subtype_t type, 4868 void *arg, 4869 sctp_cmd_seq_t *commands) 4870 { 4871 struct sctp_chunk *reply = NULL; 4872 4873 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 4874 4875 reply = sctp_make_abort(asoc, NULL, 0); 4876 if (!reply) 4877 goto nomem; 4878 4879 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4880 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4881 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4882 4883 return SCTP_DISPOSITION_DELETE_TCB; 4884 nomem: 4885 return SCTP_DISPOSITION_NOMEM; 4886 } 4887 4888 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 4889 * the association is automatically closed by starting the shutdown process. 4890 * The work that needs to be done is same as when SHUTDOWN is initiated by 4891 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 4892 */ 4893 sctp_disposition_t sctp_sf_autoclose_timer_expire( 4894 const struct sctp_endpoint *ep, 4895 const struct sctp_association *asoc, 4896 const sctp_subtype_t type, 4897 void *arg, 4898 sctp_cmd_seq_t *commands) 4899 { 4900 int disposition; 4901 4902 /* From 9.2 Shutdown of an Association 4903 * Upon receipt of the SHUTDOWN primitive from its upper 4904 * layer, the endpoint enters SHUTDOWN-PENDING state and 4905 * remains there until all outstanding data has been 4906 * acknowledged by its peer. The endpoint accepts no new data 4907 * from its upper layer, but retransmits data to the far end 4908 * if necessary to fill gaps. 4909 */ 4910 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4911 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4912 4913 /* sctpimpguide-05 Section 2.12.2 4914 * The sender of the SHUTDOWN MAY also start an overall guard timer 4915 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4916 */ 4917 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4918 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4919 disposition = SCTP_DISPOSITION_CONSUME; 4920 if (sctp_outq_is_empty(&asoc->outqueue)) { 4921 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4922 arg, commands); 4923 } 4924 return disposition; 4925 } 4926 4927 /***************************************************************************** 4928 * These are sa state functions which could apply to all types of events. 4929 ****************************************************************************/ 4930 4931 /* 4932 * This table entry is not implemented. 4933 * 4934 * Inputs 4935 * (endpoint, asoc, chunk) 4936 * 4937 * The return value is the disposition of the chunk. 4938 */ 4939 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 4940 const struct sctp_association *asoc, 4941 const sctp_subtype_t type, 4942 void *arg, 4943 sctp_cmd_seq_t *commands) 4944 { 4945 return SCTP_DISPOSITION_NOT_IMPL; 4946 } 4947 4948 /* 4949 * This table entry represents a bug. 4950 * 4951 * Inputs 4952 * (endpoint, asoc, chunk) 4953 * 4954 * The return value is the disposition of the chunk. 4955 */ 4956 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 4957 const struct sctp_association *asoc, 4958 const sctp_subtype_t type, 4959 void *arg, 4960 sctp_cmd_seq_t *commands) 4961 { 4962 return SCTP_DISPOSITION_BUG; 4963 } 4964 4965 /* 4966 * This table entry represents the firing of a timer in the wrong state. 4967 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 4968 * when the association is in the wrong state. This event should 4969 * be ignored, so as to prevent any rearming of the timer. 4970 * 4971 * Inputs 4972 * (endpoint, asoc, chunk) 4973 * 4974 * The return value is the disposition of the chunk. 4975 */ 4976 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 4977 const struct sctp_association *asoc, 4978 const sctp_subtype_t type, 4979 void *arg, 4980 sctp_cmd_seq_t *commands) 4981 { 4982 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 4983 return SCTP_DISPOSITION_CONSUME; 4984 } 4985 4986 /******************************************************************** 4987 * 2nd Level Abstractions 4988 ********************************************************************/ 4989 4990 /* Pull the SACK chunk based on the SACK header. */ 4991 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 4992 { 4993 struct sctp_sackhdr *sack; 4994 unsigned int len; 4995 __u16 num_blocks; 4996 __u16 num_dup_tsns; 4997 4998 /* Protect ourselves from reading too far into 4999 * the skb from a bogus sender. 5000 */ 5001 sack = (struct sctp_sackhdr *) chunk->skb->data; 5002 5003 num_blocks = ntohs(sack->num_gap_ack_blocks); 5004 num_dup_tsns = ntohs(sack->num_dup_tsns); 5005 len = sizeof(struct sctp_sackhdr); 5006 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5007 if (len > chunk->skb->len) 5008 return NULL; 5009 5010 skb_pull(chunk->skb, len); 5011 5012 return sack; 5013 } 5014 5015 /* Create an ABORT packet to be sent as a response, with the specified 5016 * error causes. 5017 */ 5018 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5019 const struct sctp_association *asoc, 5020 struct sctp_chunk *chunk, 5021 const void *payload, 5022 size_t paylen) 5023 { 5024 struct sctp_packet *packet; 5025 struct sctp_chunk *abort; 5026 5027 packet = sctp_ootb_pkt_new(asoc, chunk); 5028 5029 if (packet) { 5030 /* Make an ABORT. 5031 * The T bit will be set if the asoc is NULL. 5032 */ 5033 abort = sctp_make_abort(asoc, chunk, paylen); 5034 if (!abort) { 5035 sctp_ootb_pkt_free(packet); 5036 return NULL; 5037 } 5038 5039 /* Reflect vtag if T-Bit is set */ 5040 if (sctp_test_T_bit(abort)) 5041 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5042 5043 /* Add specified error causes, i.e., payload, to the 5044 * end of the chunk. 5045 */ 5046 sctp_addto_chunk(abort, paylen, payload); 5047 5048 /* Set the skb to the belonging sock for accounting. */ 5049 abort->skb->sk = ep->base.sk; 5050 5051 sctp_packet_append_chunk(packet, abort); 5052 5053 } 5054 5055 return packet; 5056 } 5057 5058 /* Allocate a packet for responding in the OOTB conditions. */ 5059 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5060 const struct sctp_chunk *chunk) 5061 { 5062 struct sctp_packet *packet; 5063 struct sctp_transport *transport; 5064 __u16 sport; 5065 __u16 dport; 5066 __u32 vtag; 5067 5068 /* Get the source and destination port from the inbound packet. */ 5069 sport = ntohs(chunk->sctp_hdr->dest); 5070 dport = ntohs(chunk->sctp_hdr->source); 5071 5072 /* The V-tag is going to be the same as the inbound packet if no 5073 * association exists, otherwise, use the peer's vtag. 5074 */ 5075 if (asoc) { 5076 vtag = asoc->peer.i.init_tag; 5077 } else { 5078 /* Special case the INIT and stale COOKIE_ECHO as there is no 5079 * vtag yet. 5080 */ 5081 switch(chunk->chunk_hdr->type) { 5082 case SCTP_CID_INIT: 5083 { 5084 sctp_init_chunk_t *init; 5085 5086 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5087 vtag = ntohl(init->init_hdr.init_tag); 5088 break; 5089 } 5090 default: 5091 vtag = ntohl(chunk->sctp_hdr->vtag); 5092 break; 5093 } 5094 } 5095 5096 /* Make a transport for the bucket, Eliza... */ 5097 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5098 if (!transport) 5099 goto nomem; 5100 5101 /* Cache a route for the transport with the chunk's destination as 5102 * the source address. 5103 */ 5104 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5105 sctp_sk(sctp_get_ctl_sock())); 5106 5107 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5108 packet = sctp_packet_config(packet, vtag, 0); 5109 5110 return packet; 5111 5112 nomem: 5113 return NULL; 5114 } 5115 5116 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5117 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5118 { 5119 sctp_transport_free(packet->transport); 5120 } 5121 5122 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5123 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5124 const struct sctp_association *asoc, 5125 const struct sctp_chunk *chunk, 5126 sctp_cmd_seq_t *commands, 5127 struct sctp_chunk *err_chunk) 5128 { 5129 struct sctp_packet *packet; 5130 5131 if (err_chunk) { 5132 packet = sctp_ootb_pkt_new(asoc, chunk); 5133 if (packet) { 5134 struct sctp_signed_cookie *cookie; 5135 5136 /* Override the OOTB vtag from the cookie. */ 5137 cookie = chunk->subh.cookie_hdr; 5138 packet->vtag = cookie->c.peer_vtag; 5139 5140 /* Set the skb to the belonging sock for accounting. */ 5141 err_chunk->skb->sk = ep->base.sk; 5142 sctp_packet_append_chunk(packet, err_chunk); 5143 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5144 SCTP_PACKET(packet)); 5145 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5146 } else 5147 sctp_chunk_free (err_chunk); 5148 } 5149 } 5150 5151 5152 /* Process a data chunk */ 5153 static int sctp_eat_data(const struct sctp_association *asoc, 5154 struct sctp_chunk *chunk, 5155 sctp_cmd_seq_t *commands) 5156 { 5157 sctp_datahdr_t *data_hdr; 5158 struct sctp_chunk *err; 5159 size_t datalen; 5160 sctp_verb_t deliver; 5161 int tmp; 5162 __u32 tsn; 5163 int account_value; 5164 struct sock *sk = asoc->base.sk; 5165 5166 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5167 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5168 5169 tsn = ntohl(data_hdr->tsn); 5170 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5171 5172 /* ASSERT: Now skb->data is really the user data. */ 5173 5174 /* 5175 * if we are established, and we have used up our receive 5176 * buffer memory, drop the frame 5177 */ 5178 if (asoc->state == SCTP_STATE_ESTABLISHED) { 5179 /* 5180 * If the receive buffer policy is 1, then each 5181 * association can allocate up to sk_rcvbuf bytes 5182 * otherwise, all the associations in aggregate 5183 * may allocate up to sk_rcvbuf bytes 5184 */ 5185 if (asoc->ep->rcvbuf_policy) 5186 account_value = atomic_read(&asoc->rmem_alloc); 5187 else 5188 account_value = atomic_read(&sk->sk_rmem_alloc); 5189 5190 if (account_value > sk->sk_rcvbuf) 5191 return SCTP_IERROR_IGNORE_TSN; 5192 } 5193 5194 /* Process ECN based congestion. 5195 * 5196 * Since the chunk structure is reused for all chunks within 5197 * a packet, we use ecn_ce_done to track if we've already 5198 * done CE processing for this packet. 5199 * 5200 * We need to do ECN processing even if we plan to discard the 5201 * chunk later. 5202 */ 5203 5204 if (!chunk->ecn_ce_done) { 5205 struct sctp_af *af; 5206 chunk->ecn_ce_done = 1; 5207 5208 af = sctp_get_af_specific( 5209 ipver2af(chunk->skb->nh.iph->version)); 5210 5211 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5212 /* Do real work as sideffect. */ 5213 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5214 SCTP_U32(tsn)); 5215 } 5216 } 5217 5218 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5219 if (tmp < 0) { 5220 /* The TSN is too high--silently discard the chunk and 5221 * count on it getting retransmitted later. 5222 */ 5223 return SCTP_IERROR_HIGH_TSN; 5224 } else if (tmp > 0) { 5225 /* This is a duplicate. Record it. */ 5226 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5227 return SCTP_IERROR_DUP_TSN; 5228 } 5229 5230 /* This is a new TSN. */ 5231 5232 /* Discard if there is no room in the receive window. 5233 * Actually, allow a little bit of overflow (up to a MTU). 5234 */ 5235 datalen = ntohs(chunk->chunk_hdr->length); 5236 datalen -= sizeof(sctp_data_chunk_t); 5237 5238 deliver = SCTP_CMD_CHUNK_ULP; 5239 5240 /* Think about partial delivery. */ 5241 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5242 5243 /* Even if we don't accept this chunk there is 5244 * memory pressure. 5245 */ 5246 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5247 } 5248 5249 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5250 * seems a bit troublesome in that frag_point varies based on 5251 * PMTU. In cases, such as loopback, this might be a rather 5252 * large spill over. 5253 */ 5254 if (!asoc->rwnd || asoc->rwnd_over || 5255 (datalen > asoc->rwnd + asoc->frag_point)) { 5256 5257 /* If this is the next TSN, consider reneging to make 5258 * room. Note: Playing nice with a confused sender. A 5259 * malicious sender can still eat up all our buffer 5260 * space and in the future we may want to detect and 5261 * do more drastic reneging. 5262 */ 5263 if (sctp_tsnmap_has_gap(&asoc->peer.tsn_map) && 5264 (sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1) == tsn) { 5265 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5266 deliver = SCTP_CMD_RENEGE; 5267 } else { 5268 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5269 "rwnd: %d\n", tsn, datalen, 5270 asoc->rwnd); 5271 return SCTP_IERROR_IGNORE_TSN; 5272 } 5273 } 5274 5275 /* 5276 * Section 3.3.10.9 No User Data (9) 5277 * 5278 * Cause of error 5279 * --------------- 5280 * No User Data: This error cause is returned to the originator of a 5281 * DATA chunk if a received DATA chunk has no user data. 5282 */ 5283 if (unlikely(0 == datalen)) { 5284 err = sctp_make_abort_no_data(asoc, chunk, tsn); 5285 if (err) { 5286 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5287 SCTP_CHUNK(err)); 5288 } 5289 /* We are going to ABORT, so we might as well stop 5290 * processing the rest of the chunks in the packet. 5291 */ 5292 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 5293 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5294 SCTP_U32(SCTP_ERROR_NO_DATA)); 5295 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5296 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5297 return SCTP_IERROR_NO_DATA; 5298 } 5299 5300 /* If definately accepting the DATA chunk, record its TSN, otherwise 5301 * wait for renege processing. 5302 */ 5303 if (SCTP_CMD_CHUNK_ULP == deliver) 5304 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 5305 5306 /* Note: Some chunks may get overcounted (if we drop) or overcounted 5307 * if we renege and the chunk arrives again. 5308 */ 5309 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 5310 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 5311 else 5312 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 5313 5314 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 5315 * 5316 * If an endpoint receive a DATA chunk with an invalid stream 5317 * identifier, it shall acknowledge the reception of the DATA chunk 5318 * following the normal procedure, immediately send an ERROR chunk 5319 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 5320 * and discard the DATA chunk. 5321 */ 5322 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { 5323 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 5324 &data_hdr->stream, 5325 sizeof(data_hdr->stream)); 5326 if (err) 5327 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5328 SCTP_CHUNK(err)); 5329 return SCTP_IERROR_BAD_STREAM; 5330 } 5331 5332 /* Send the data up to the user. Note: Schedule the 5333 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 5334 * chunk needs the updated rwnd. 5335 */ 5336 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 5337 5338 return SCTP_IERROR_NO_ERROR; 5339 } 5340