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 sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 94 const struct sctp_association *asoc, 95 const sctp_subtype_t type, 96 void *arg, 97 sctp_cmd_seq_t *commands); 98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 99 100 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 101 __be16 error, int sk_err, 102 const struct sctp_association *asoc, 103 struct sctp_transport *transport); 104 105 static sctp_disposition_t sctp_sf_abort_violation( 106 const struct sctp_endpoint *ep, 107 const struct sctp_association *asoc, 108 void *arg, 109 sctp_cmd_seq_t *commands, 110 const __u8 *payload, 111 const size_t paylen); 112 113 static sctp_disposition_t sctp_sf_violation_chunklen( 114 const struct sctp_endpoint *ep, 115 const struct sctp_association *asoc, 116 const sctp_subtype_t type, 117 void *arg, 118 sctp_cmd_seq_t *commands); 119 120 static sctp_disposition_t sctp_sf_violation_paramlen( 121 const struct sctp_endpoint *ep, 122 const struct sctp_association *asoc, 123 const sctp_subtype_t type, 124 void *arg, 125 sctp_cmd_seq_t *commands); 126 127 static sctp_disposition_t sctp_sf_violation_ctsn( 128 const struct sctp_endpoint *ep, 129 const struct sctp_association *asoc, 130 const sctp_subtype_t type, 131 void *arg, 132 sctp_cmd_seq_t *commands); 133 134 static sctp_disposition_t sctp_sf_violation_chunk( 135 const struct sctp_endpoint *ep, 136 const struct sctp_association *asoc, 137 const sctp_subtype_t type, 138 void *arg, 139 sctp_cmd_seq_t *commands); 140 141 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const sctp_subtype_t type, 144 struct sctp_chunk *chunk); 145 146 /* Small helper function that checks if the chunk length 147 * is of the appropriate length. The 'required_length' argument 148 * is set to be the size of a specific chunk we are testing. 149 * Return Values: 1 = Valid length 150 * 0 = Invalid length 151 * 152 */ 153 static inline int 154 sctp_chunk_length_valid(struct sctp_chunk *chunk, 155 __u16 required_length) 156 { 157 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 158 159 if (unlikely(chunk_length < required_length)) 160 return 0; 161 162 return 1; 163 } 164 165 /********************************************************** 166 * These are the state functions for handling chunk events. 167 **********************************************************/ 168 169 /* 170 * Process the final SHUTDOWN COMPLETE. 171 * 172 * Section: 4 (C) (diagram), 9.2 173 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 174 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 175 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 176 * should stop the T2-shutdown timer and remove all knowledge of the 177 * association (and thus the association enters the CLOSED state). 178 * 179 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 180 * C) Rules for packet carrying SHUTDOWN COMPLETE: 181 * ... 182 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 183 * if the Verification Tag field of the packet matches its own tag and 184 * the T bit is not set 185 * OR 186 * it is set to its peer's tag and the T bit is set in the Chunk 187 * Flags. 188 * Otherwise, the receiver MUST silently discard the packet 189 * and take no further action. An endpoint MUST ignore the 190 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 191 * 192 * Inputs 193 * (endpoint, asoc, chunk) 194 * 195 * Outputs 196 * (asoc, reply_msg, msg_up, timers, counters) 197 * 198 * The return value is the disposition of the chunk. 199 */ 200 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, 201 const struct sctp_association *asoc, 202 const sctp_subtype_t type, 203 void *arg, 204 sctp_cmd_seq_t *commands) 205 { 206 struct sctp_chunk *chunk = arg; 207 struct sctp_ulpevent *ev; 208 209 if (!sctp_vtag_verify_either(chunk, asoc)) 210 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 211 212 /* RFC 2960 6.10 Bundling 213 * 214 * An endpoint MUST NOT bundle INIT, INIT ACK or 215 * SHUTDOWN COMPLETE with any other chunks. 216 */ 217 if (!chunk->singleton) 218 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 219 220 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 221 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 222 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 223 commands); 224 225 /* RFC 2960 10.2 SCTP-to-ULP 226 * 227 * H) SHUTDOWN COMPLETE notification 228 * 229 * When SCTP completes the shutdown procedures (section 9.2) this 230 * notification is passed to the upper layer. 231 */ 232 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 233 0, 0, 0, NULL, GFP_ATOMIC); 234 if (ev) 235 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 236 SCTP_ULPEVENT(ev)); 237 238 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 239 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 240 * not the chunk should be discarded. If the endpoint is in 241 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 242 * T2-shutdown timer and remove all knowledge of the 243 * association (and thus the association enters the CLOSED 244 * state). 245 */ 246 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 247 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 248 249 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 250 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 251 252 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 253 SCTP_STATE(SCTP_STATE_CLOSED)); 254 255 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 256 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 257 258 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 259 260 return SCTP_DISPOSITION_DELETE_TCB; 261 } 262 263 /* 264 * Respond to a normal INIT chunk. 265 * We are the side that is being asked for an association. 266 * 267 * Section: 5.1 Normal Establishment of an Association, B 268 * B) "Z" shall respond immediately with an INIT ACK chunk. The 269 * destination IP address of the INIT ACK MUST be set to the source 270 * IP address of the INIT to which this INIT ACK is responding. In 271 * the response, besides filling in other parameters, "Z" must set the 272 * Verification Tag field to Tag_A, and also provide its own 273 * Verification Tag (Tag_Z) in the Initiate Tag field. 274 * 275 * Verification Tag: Must be 0. 276 * 277 * Inputs 278 * (endpoint, asoc, chunk) 279 * 280 * Outputs 281 * (asoc, reply_msg, msg_up, timers, counters) 282 * 283 * The return value is the disposition of the chunk. 284 */ 285 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 286 const struct sctp_association *asoc, 287 const sctp_subtype_t type, 288 void *arg, 289 sctp_cmd_seq_t *commands) 290 { 291 struct sctp_chunk *chunk = arg; 292 struct sctp_chunk *repl; 293 struct sctp_association *new_asoc; 294 struct sctp_chunk *err_chunk; 295 struct sctp_packet *packet; 296 sctp_unrecognized_param_t *unk_param; 297 int len; 298 299 /* 6.10 Bundling 300 * An endpoint MUST NOT bundle INIT, INIT ACK or 301 * SHUTDOWN COMPLETE with any other chunks. 302 * 303 * IG Section 2.11.2 304 * Furthermore, we require that the receiver of an INIT chunk MUST 305 * enforce these rules by silently discarding an arriving packet 306 * with an INIT chunk that is bundled with other chunks. 307 */ 308 if (!chunk->singleton) 309 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 310 311 /* If the packet is an OOTB packet which is temporarily on the 312 * control endpoint, respond with an ABORT. 313 */ 314 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 315 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 316 317 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 318 * Tag. 319 */ 320 if (chunk->sctp_hdr->vtag != 0) 321 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 322 323 /* Make sure that the INIT chunk has a valid length. 324 * Normally, this would cause an ABORT with a Protocol Violation 325 * error, but since we don't have an association, we'll 326 * just discard the packet. 327 */ 328 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 329 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 330 331 /* Verify the INIT chunk before processing it. */ 332 err_chunk = NULL; 333 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 334 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 335 &err_chunk)) { 336 /* This chunk contains fatal error. It is to be discarded. 337 * Send an ABORT, with causes if there is any. 338 */ 339 if (err_chunk) { 340 packet = sctp_abort_pkt_new(ep, asoc, arg, 341 (__u8 *)(err_chunk->chunk_hdr) + 342 sizeof(sctp_chunkhdr_t), 343 ntohs(err_chunk->chunk_hdr->length) - 344 sizeof(sctp_chunkhdr_t)); 345 346 sctp_chunk_free(err_chunk); 347 348 if (packet) { 349 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 350 SCTP_PACKET(packet)); 351 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 352 return SCTP_DISPOSITION_CONSUME; 353 } else { 354 return SCTP_DISPOSITION_NOMEM; 355 } 356 } else { 357 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 358 commands); 359 } 360 } 361 362 /* Grab the INIT header. */ 363 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 364 365 /* Tag the variable length parameters. */ 366 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 367 368 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 369 if (!new_asoc) 370 goto nomem; 371 372 /* The call, sctp_process_init(), can fail on memory allocation. */ 373 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 374 sctp_source(chunk), 375 (sctp_init_chunk_t *)chunk->chunk_hdr, 376 GFP_ATOMIC)) 377 goto nomem_init; 378 379 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 380 381 /* If there are errors need to be reported for unknown parameters, 382 * make sure to reserve enough room in the INIT ACK for them. 383 */ 384 len = 0; 385 if (err_chunk) 386 len = ntohs(err_chunk->chunk_hdr->length) - 387 sizeof(sctp_chunkhdr_t); 388 389 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 390 goto nomem_init; 391 392 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 393 if (!repl) 394 goto nomem_init; 395 396 /* If there are errors need to be reported for unknown parameters, 397 * include them in the outgoing INIT ACK as "Unrecognized parameter" 398 * parameter. 399 */ 400 if (err_chunk) { 401 /* Get the "Unrecognized parameter" parameter(s) out of the 402 * ERROR chunk generated by sctp_verify_init(). Since the 403 * error cause code for "unknown parameter" and the 404 * "Unrecognized parameter" type is the same, we can 405 * construct the parameters in INIT ACK by copying the 406 * ERROR causes over. 407 */ 408 unk_param = (sctp_unrecognized_param_t *) 409 ((__u8 *)(err_chunk->chunk_hdr) + 410 sizeof(sctp_chunkhdr_t)); 411 /* Replace the cause code with the "Unrecognized parameter" 412 * parameter type. 413 */ 414 sctp_addto_chunk(repl, len, unk_param); 415 sctp_chunk_free(err_chunk); 416 } 417 418 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 419 420 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 421 422 /* 423 * Note: After sending out INIT ACK with the State Cookie parameter, 424 * "Z" MUST NOT allocate any resources, nor keep any states for the 425 * new association. Otherwise, "Z" will be vulnerable to resource 426 * attacks. 427 */ 428 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 429 430 return SCTP_DISPOSITION_DELETE_TCB; 431 432 nomem_init: 433 sctp_association_free(new_asoc); 434 nomem: 435 if (err_chunk) 436 sctp_chunk_free(err_chunk); 437 return SCTP_DISPOSITION_NOMEM; 438 } 439 440 /* 441 * Respond to a normal INIT ACK chunk. 442 * We are the side that is initiating the association. 443 * 444 * Section: 5.1 Normal Establishment of an Association, C 445 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 446 * timer and leave COOKIE-WAIT state. "A" shall then send the State 447 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 448 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 449 * 450 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 451 * DATA chunks, but it MUST be the first chunk in the packet and 452 * until the COOKIE ACK is returned the sender MUST NOT send any 453 * other packets to the peer. 454 * 455 * Verification Tag: 3.3.3 456 * If the value of the Initiate Tag in a received INIT ACK chunk is 457 * found to be 0, the receiver MUST treat it as an error and close the 458 * association by transmitting an ABORT. 459 * 460 * Inputs 461 * (endpoint, asoc, chunk) 462 * 463 * Outputs 464 * (asoc, reply_msg, msg_up, timers, counters) 465 * 466 * The return value is the disposition of the chunk. 467 */ 468 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, 469 const struct sctp_association *asoc, 470 const sctp_subtype_t type, 471 void *arg, 472 sctp_cmd_seq_t *commands) 473 { 474 struct sctp_chunk *chunk = arg; 475 sctp_init_chunk_t *initchunk; 476 struct sctp_chunk *err_chunk; 477 struct sctp_packet *packet; 478 sctp_error_t error; 479 480 if (!sctp_vtag_verify(chunk, asoc)) 481 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 482 483 /* 6.10 Bundling 484 * An endpoint MUST NOT bundle INIT, INIT ACK or 485 * SHUTDOWN COMPLETE with any other chunks. 486 */ 487 if (!chunk->singleton) 488 return sctp_sf_violation_chunk(ep, asoc, type, arg, commands); 489 490 /* Make sure that the INIT-ACK chunk has a valid length */ 491 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 492 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 493 commands); 494 /* Grab the INIT header. */ 495 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 496 497 /* Verify the INIT chunk before processing it. */ 498 err_chunk = NULL; 499 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 500 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 501 &err_chunk)) { 502 503 /* This chunk contains fatal error. It is to be discarded. 504 * Send an ABORT, with causes if there is any. 505 */ 506 if (err_chunk) { 507 packet = sctp_abort_pkt_new(ep, asoc, arg, 508 (__u8 *)(err_chunk->chunk_hdr) + 509 sizeof(sctp_chunkhdr_t), 510 ntohs(err_chunk->chunk_hdr->length) - 511 sizeof(sctp_chunkhdr_t)); 512 513 sctp_chunk_free(err_chunk); 514 515 if (packet) { 516 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 517 SCTP_PACKET(packet)); 518 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 519 error = SCTP_ERROR_INV_PARAM; 520 } else { 521 error = SCTP_ERROR_NO_RESOURCE; 522 } 523 } else { 524 sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 525 error = SCTP_ERROR_INV_PARAM; 526 } 527 528 /* SCTP-AUTH, Section 6.3: 529 * It should be noted that if the receiver wants to tear 530 * down an association in an authenticated way only, the 531 * handling of malformed packets should not result in 532 * tearing down the association. 533 * 534 * This means that if we only want to abort associations 535 * in an authenticated way (i.e AUTH+ABORT), then we 536 * can't destory this association just becuase the packet 537 * was malformed. 538 */ 539 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 540 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 541 542 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 543 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, 544 asoc, chunk->transport); 545 } 546 547 /* Tag the variable length parameters. Note that we never 548 * convert the parameters in an INIT chunk. 549 */ 550 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 551 552 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 553 554 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 555 SCTP_PEER_INIT(initchunk)); 556 557 /* Reset init error count upon receipt of INIT-ACK. */ 558 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 559 560 /* 5.1 C) "A" shall stop the T1-init timer and leave 561 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 562 * timer, and enter the COOKIE-ECHOED state. 563 */ 564 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 565 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 566 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 567 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 568 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 569 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 570 571 /* SCTP-AUTH: genereate the assocition shared keys so that 572 * we can potentially signe the COOKIE-ECHO. 573 */ 574 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 575 576 /* 5.1 C) "A" shall then send the State Cookie received in the 577 * INIT ACK chunk in a COOKIE ECHO chunk, ... 578 */ 579 /* If there is any errors to report, send the ERROR chunk generated 580 * for unknown parameters as well. 581 */ 582 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 583 SCTP_CHUNK(err_chunk)); 584 585 return SCTP_DISPOSITION_CONSUME; 586 } 587 588 /* 589 * Respond to a normal COOKIE ECHO chunk. 590 * We are the side that is being asked for an association. 591 * 592 * Section: 5.1 Normal Establishment of an Association, D 593 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 594 * with a COOKIE ACK chunk after building a TCB and moving to 595 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 596 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 597 * chunk MUST be the first chunk in the packet. 598 * 599 * IMPLEMENTATION NOTE: An implementation may choose to send the 600 * Communication Up notification to the SCTP user upon reception 601 * of a valid COOKIE ECHO chunk. 602 * 603 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 604 * D) Rules for packet carrying a COOKIE ECHO 605 * 606 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 607 * Initial Tag received in the INIT ACK. 608 * 609 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 610 * 611 * Inputs 612 * (endpoint, asoc, chunk) 613 * 614 * Outputs 615 * (asoc, reply_msg, msg_up, timers, counters) 616 * 617 * The return value is the disposition of the chunk. 618 */ 619 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, 620 const struct sctp_association *asoc, 621 const sctp_subtype_t type, void *arg, 622 sctp_cmd_seq_t *commands) 623 { 624 struct sctp_chunk *chunk = arg; 625 struct sctp_association *new_asoc; 626 sctp_init_chunk_t *peer_init; 627 struct sctp_chunk *repl; 628 struct sctp_ulpevent *ev, *ai_ev = NULL; 629 int error = 0; 630 struct sctp_chunk *err_chk_p; 631 struct sock *sk; 632 633 /* If the packet is an OOTB packet which is temporarily on the 634 * control endpoint, respond with an ABORT. 635 */ 636 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 637 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 638 639 /* Make sure that the COOKIE_ECHO chunk has a valid length. 640 * In this case, we check that we have enough for at least a 641 * chunk header. More detailed verification is done 642 * in sctp_unpack_cookie(). 643 */ 644 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 645 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 646 647 /* If the endpoint is not listening or if the number of associations 648 * on the TCP-style socket exceed the max backlog, respond with an 649 * ABORT. 650 */ 651 sk = ep->base.sk; 652 if (!sctp_sstate(sk, LISTENING) || 653 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 654 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 655 656 /* "Decode" the chunk. We have no optional parameters so we 657 * are in good shape. 658 */ 659 chunk->subh.cookie_hdr = 660 (struct sctp_signed_cookie *)chunk->skb->data; 661 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 662 sizeof(sctp_chunkhdr_t))) 663 goto nomem; 664 665 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 666 * "Z" will reply with a COOKIE ACK chunk after building a TCB 667 * and moving to the ESTABLISHED state. 668 */ 669 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 670 &err_chk_p); 671 672 /* FIXME: 673 * If the re-build failed, what is the proper error path 674 * from here? 675 * 676 * [We should abort the association. --piggy] 677 */ 678 if (!new_asoc) { 679 /* FIXME: Several errors are possible. A bad cookie should 680 * be silently discarded, but think about logging it too. 681 */ 682 switch (error) { 683 case -SCTP_IERROR_NOMEM: 684 goto nomem; 685 686 case -SCTP_IERROR_STALE_COOKIE: 687 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 688 err_chk_p); 689 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 690 691 case -SCTP_IERROR_BAD_SIG: 692 default: 693 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 694 } 695 } 696 697 698 /* Delay state machine commands until later. 699 * 700 * Re-build the bind address for the association is done in 701 * the sctp_unpack_cookie() already. 702 */ 703 /* This is a brand-new association, so these are not yet side 704 * effects--it is safe to run them here. 705 */ 706 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 707 708 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 709 &chunk->subh.cookie_hdr->c.peer_addr, 710 peer_init, GFP_ATOMIC)) 711 goto nomem_init; 712 713 /* SCTP-AUTH: Now that we've populate required fields in 714 * sctp_process_init, set up the assocaition shared keys as 715 * necessary so that we can potentially authenticate the ACK 716 */ 717 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 718 if (error) 719 goto nomem_init; 720 721 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 722 * is supposed to be authenticated and we have to do delayed 723 * authentication. We've just recreated the association using 724 * the information in the cookie and now it's much easier to 725 * do the authentication. 726 */ 727 if (chunk->auth_chunk) { 728 struct sctp_chunk auth; 729 sctp_ierror_t ret; 730 731 /* set-up our fake chunk so that we can process it */ 732 auth.skb = chunk->auth_chunk; 733 auth.asoc = chunk->asoc; 734 auth.sctp_hdr = chunk->sctp_hdr; 735 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 736 sizeof(sctp_chunkhdr_t)); 737 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 738 auth.transport = chunk->transport; 739 740 ret = sctp_sf_authenticate(ep, new_asoc, type, &auth); 741 742 /* We can now safely free the auth_chunk clone */ 743 kfree_skb(chunk->auth_chunk); 744 745 if (ret != SCTP_IERROR_NO_ERROR) { 746 sctp_association_free(new_asoc); 747 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 748 } 749 } 750 751 repl = sctp_make_cookie_ack(new_asoc, chunk); 752 if (!repl) 753 goto nomem_init; 754 755 /* RFC 2960 5.1 Normal Establishment of an Association 756 * 757 * D) IMPLEMENTATION NOTE: An implementation may choose to 758 * send the Communication Up notification to the SCTP user 759 * upon reception of a valid COOKIE ECHO chunk. 760 */ 761 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 762 new_asoc->c.sinit_num_ostreams, 763 new_asoc->c.sinit_max_instreams, 764 NULL, GFP_ATOMIC); 765 if (!ev) 766 goto nomem_ev; 767 768 /* Sockets API Draft Section 5.3.1.6 769 * When a peer sends a Adaptation Layer Indication parameter , SCTP 770 * delivers this notification to inform the application that of the 771 * peers requested adaptation layer. 772 */ 773 if (new_asoc->peer.adaptation_ind) { 774 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 775 GFP_ATOMIC); 776 if (!ai_ev) 777 goto nomem_aiev; 778 } 779 780 /* Add all the state machine commands now since we've created 781 * everything. This way we don't introduce memory corruptions 782 * during side-effect processing and correclty count established 783 * associations. 784 */ 785 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 786 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 787 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 788 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 789 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 790 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 791 792 if (new_asoc->autoclose) 793 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 794 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 795 796 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 797 798 /* This will send the COOKIE ACK */ 799 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 800 801 /* Queue the ASSOC_CHANGE event */ 802 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 803 804 /* Send up the Adaptation Layer Indication event */ 805 if (ai_ev) 806 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 807 SCTP_ULPEVENT(ai_ev)); 808 809 return SCTP_DISPOSITION_CONSUME; 810 811 nomem_aiev: 812 sctp_ulpevent_free(ev); 813 nomem_ev: 814 sctp_chunk_free(repl); 815 nomem_init: 816 sctp_association_free(new_asoc); 817 nomem: 818 return SCTP_DISPOSITION_NOMEM; 819 } 820 821 /* 822 * Respond to a normal COOKIE ACK chunk. 823 * We are the side that is being asked for an association. 824 * 825 * RFC 2960 5.1 Normal Establishment of an Association 826 * 827 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 828 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 829 * timer. It may also notify its ULP about the successful 830 * establishment of the association with a Communication Up 831 * notification (see Section 10). 832 * 833 * Verification Tag: 834 * Inputs 835 * (endpoint, asoc, chunk) 836 * 837 * Outputs 838 * (asoc, reply_msg, msg_up, timers, counters) 839 * 840 * The return value is the disposition of the chunk. 841 */ 842 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, 843 const struct sctp_association *asoc, 844 const sctp_subtype_t type, void *arg, 845 sctp_cmd_seq_t *commands) 846 { 847 struct sctp_chunk *chunk = arg; 848 struct sctp_ulpevent *ev; 849 850 if (!sctp_vtag_verify(chunk, asoc)) 851 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 852 853 /* Verify that the chunk length for the COOKIE-ACK is OK. 854 * If we don't do this, any bundled chunks may be junked. 855 */ 856 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 857 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 858 commands); 859 860 /* Reset init error count upon receipt of COOKIE-ACK, 861 * to avoid problems with the managemement of this 862 * counter in stale cookie situations when a transition back 863 * from the COOKIE-ECHOED state to the COOKIE-WAIT 864 * state is performed. 865 */ 866 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 867 868 /* RFC 2960 5.1 Normal Establishment of an Association 869 * 870 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 871 * from the COOKIE-ECHOED state to the ESTABLISHED state, 872 * stopping the T1-cookie timer. 873 */ 874 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 875 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 876 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 877 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 878 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 879 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); 880 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 881 if (asoc->autoclose) 882 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 883 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 884 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 885 886 /* It may also notify its ULP about the successful 887 * establishment of the association with a Communication Up 888 * notification (see Section 10). 889 */ 890 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 891 0, asoc->c.sinit_num_ostreams, 892 asoc->c.sinit_max_instreams, 893 NULL, GFP_ATOMIC); 894 895 if (!ev) 896 goto nomem; 897 898 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 899 900 /* Sockets API Draft Section 5.3.1.6 901 * When a peer sends a Adaptation Layer Indication parameter , SCTP 902 * delivers this notification to inform the application that of the 903 * peers requested adaptation layer. 904 */ 905 if (asoc->peer.adaptation_ind) { 906 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 907 if (!ev) 908 goto nomem; 909 910 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 911 SCTP_ULPEVENT(ev)); 912 } 913 914 return SCTP_DISPOSITION_CONSUME; 915 nomem: 916 return SCTP_DISPOSITION_NOMEM; 917 } 918 919 /* Generate and sendout a heartbeat packet. */ 920 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 921 const struct sctp_association *asoc, 922 const sctp_subtype_t type, 923 void *arg, 924 sctp_cmd_seq_t *commands) 925 { 926 struct sctp_transport *transport = (struct sctp_transport *) arg; 927 struct sctp_chunk *reply; 928 sctp_sender_hb_info_t hbinfo; 929 size_t paylen = 0; 930 931 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; 932 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); 933 hbinfo.daddr = transport->ipaddr; 934 hbinfo.sent_at = jiffies; 935 hbinfo.hb_nonce = transport->hb_nonce; 936 937 /* Send a heartbeat to our peer. */ 938 paylen = sizeof(sctp_sender_hb_info_t); 939 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); 940 if (!reply) 941 return SCTP_DISPOSITION_NOMEM; 942 943 /* Set rto_pending indicating that an RTT measurement 944 * is started with this heartbeat chunk. 945 */ 946 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 947 SCTP_TRANSPORT(transport)); 948 949 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 950 return SCTP_DISPOSITION_CONSUME; 951 } 952 953 /* Generate a HEARTBEAT packet on the given transport. */ 954 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 955 const struct sctp_association *asoc, 956 const sctp_subtype_t type, 957 void *arg, 958 sctp_cmd_seq_t *commands) 959 { 960 struct sctp_transport *transport = (struct sctp_transport *) arg; 961 962 if (asoc->overall_error_count >= asoc->max_retrans) { 963 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 964 SCTP_ERROR(ETIMEDOUT)); 965 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 966 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 967 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 968 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 969 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 970 return SCTP_DISPOSITION_DELETE_TCB; 971 } 972 973 /* Section 3.3.5. 974 * The Sender-specific Heartbeat Info field should normally include 975 * information about the sender's current time when this HEARTBEAT 976 * chunk is sent and the destination transport address to which this 977 * HEARTBEAT is sent (see Section 8.3). 978 */ 979 980 if (transport->param_flags & SPP_HB_ENABLE) { 981 if (SCTP_DISPOSITION_NOMEM == 982 sctp_sf_heartbeat(ep, asoc, type, arg, 983 commands)) 984 return SCTP_DISPOSITION_NOMEM; 985 /* Set transport error counter and association error counter 986 * when sending heartbeat. 987 */ 988 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 989 SCTP_TRANSPORT(transport)); 990 } 991 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 992 SCTP_TRANSPORT(transport)); 993 994 return SCTP_DISPOSITION_CONSUME; 995 } 996 997 /* 998 * Process an heartbeat request. 999 * 1000 * Section: 8.3 Path Heartbeat 1001 * The receiver of the HEARTBEAT should immediately respond with a 1002 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1003 * from the received HEARTBEAT chunk. 1004 * 1005 * Verification Tag: 8.5 Verification Tag [Normal verification] 1006 * When receiving an SCTP packet, the endpoint MUST ensure that the 1007 * value in the Verification Tag field of the received SCTP packet 1008 * matches its own Tag. If the received Verification Tag value does not 1009 * match the receiver's own tag value, the receiver shall silently 1010 * discard the packet and shall not process it any further except for 1011 * those cases listed in Section 8.5.1 below. 1012 * 1013 * Inputs 1014 * (endpoint, asoc, chunk) 1015 * 1016 * Outputs 1017 * (asoc, reply_msg, msg_up, timers, counters) 1018 * 1019 * The return value is the disposition of the chunk. 1020 */ 1021 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 1022 const struct sctp_association *asoc, 1023 const sctp_subtype_t type, 1024 void *arg, 1025 sctp_cmd_seq_t *commands) 1026 { 1027 struct sctp_chunk *chunk = arg; 1028 struct sctp_chunk *reply; 1029 size_t paylen = 0; 1030 1031 if (!sctp_vtag_verify(chunk, asoc)) 1032 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1033 1034 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1035 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1036 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1037 commands); 1038 1039 /* 8.3 The receiver of the HEARTBEAT should immediately 1040 * respond with a HEARTBEAT ACK that contains the Heartbeat 1041 * Information field copied from the received HEARTBEAT chunk. 1042 */ 1043 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1044 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1045 if (!pskb_pull(chunk->skb, paylen)) 1046 goto nomem; 1047 1048 reply = sctp_make_heartbeat_ack(asoc, chunk, 1049 chunk->subh.hb_hdr, paylen); 1050 if (!reply) 1051 goto nomem; 1052 1053 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1054 return SCTP_DISPOSITION_CONSUME; 1055 1056 nomem: 1057 return SCTP_DISPOSITION_NOMEM; 1058 } 1059 1060 /* 1061 * Process the returning HEARTBEAT ACK. 1062 * 1063 * Section: 8.3 Path Heartbeat 1064 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1065 * should clear the error counter of the destination transport 1066 * address to which the HEARTBEAT was sent, and mark the destination 1067 * transport address as active if it is not so marked. The endpoint may 1068 * optionally report to the upper layer when an inactive destination 1069 * address is marked as active due to the reception of the latest 1070 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1071 * clear the association overall error count as well (as defined 1072 * in section 8.1). 1073 * 1074 * The receiver of the HEARTBEAT ACK should also perform an RTT 1075 * measurement for that destination transport address using the time 1076 * value carried in the HEARTBEAT ACK chunk. 1077 * 1078 * Verification Tag: 8.5 Verification Tag [Normal verification] 1079 * 1080 * Inputs 1081 * (endpoint, asoc, chunk) 1082 * 1083 * Outputs 1084 * (asoc, reply_msg, msg_up, timers, counters) 1085 * 1086 * The return value is the disposition of the chunk. 1087 */ 1088 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 1089 const struct sctp_association *asoc, 1090 const sctp_subtype_t type, 1091 void *arg, 1092 sctp_cmd_seq_t *commands) 1093 { 1094 struct sctp_chunk *chunk = arg; 1095 union sctp_addr from_addr; 1096 struct sctp_transport *link; 1097 sctp_sender_hb_info_t *hbinfo; 1098 unsigned long max_interval; 1099 1100 if (!sctp_vtag_verify(chunk, asoc)) 1101 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1102 1103 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1104 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1105 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1106 commands); 1107 1108 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1109 /* Make sure that the length of the parameter is what we expect */ 1110 if (ntohs(hbinfo->param_hdr.length) != 1111 sizeof(sctp_sender_hb_info_t)) { 1112 return SCTP_DISPOSITION_DISCARD; 1113 } 1114 1115 from_addr = hbinfo->daddr; 1116 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1117 1118 /* This should never happen, but lets log it if so. */ 1119 if (unlikely(!link)) { 1120 if (from_addr.sa.sa_family == AF_INET6) { 1121 if (net_ratelimit()) 1122 printk(KERN_WARNING 1123 "%s association %p could not find address " 1124 NIP6_FMT "\n", 1125 __FUNCTION__, 1126 asoc, 1127 NIP6(from_addr.v6.sin6_addr)); 1128 } else { 1129 if (net_ratelimit()) 1130 printk(KERN_WARNING 1131 "%s association %p could not find address " 1132 NIPQUAD_FMT "\n", 1133 __FUNCTION__, 1134 asoc, 1135 NIPQUAD(from_addr.v4.sin_addr.s_addr)); 1136 } 1137 return SCTP_DISPOSITION_DISCARD; 1138 } 1139 1140 /* Validate the 64-bit random nonce. */ 1141 if (hbinfo->hb_nonce != link->hb_nonce) 1142 return SCTP_DISPOSITION_DISCARD; 1143 1144 max_interval = link->hbinterval + link->rto; 1145 1146 /* Check if the timestamp looks valid. */ 1147 if (time_after(hbinfo->sent_at, jiffies) || 1148 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1149 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp" 1150 "received for transport: %p\n", 1151 __FUNCTION__, link); 1152 return SCTP_DISPOSITION_DISCARD; 1153 } 1154 1155 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1156 * the HEARTBEAT should clear the error counter of the 1157 * destination transport address to which the HEARTBEAT was 1158 * sent and mark the destination transport address as active if 1159 * it is not so marked. 1160 */ 1161 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1162 1163 return SCTP_DISPOSITION_CONSUME; 1164 } 1165 1166 /* Helper function to send out an abort for the restart 1167 * condition. 1168 */ 1169 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1170 struct sctp_chunk *init, 1171 sctp_cmd_seq_t *commands) 1172 { 1173 int len; 1174 struct sctp_packet *pkt; 1175 union sctp_addr_param *addrparm; 1176 struct sctp_errhdr *errhdr; 1177 struct sctp_endpoint *ep; 1178 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1179 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1180 1181 /* Build the error on the stack. We are way to malloc crazy 1182 * throughout the code today. 1183 */ 1184 errhdr = (struct sctp_errhdr *)buffer; 1185 addrparm = (union sctp_addr_param *)errhdr->variable; 1186 1187 /* Copy into a parm format. */ 1188 len = af->to_addr_param(ssa, addrparm); 1189 len += sizeof(sctp_errhdr_t); 1190 1191 errhdr->cause = SCTP_ERROR_RESTART; 1192 errhdr->length = htons(len); 1193 1194 /* Assign to the control socket. */ 1195 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1196 1197 /* Association is NULL since this may be a restart attack and we 1198 * want to send back the attacker's vtag. 1199 */ 1200 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1201 1202 if (!pkt) 1203 goto out; 1204 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1205 1206 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1207 1208 /* Discard the rest of the inbound packet. */ 1209 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1210 1211 out: 1212 /* Even if there is no memory, treat as a failure so 1213 * the packet will get dropped. 1214 */ 1215 return 0; 1216 } 1217 1218 /* A restart is occurring, check to make sure no new addresses 1219 * are being added as we may be under a takeover attack. 1220 */ 1221 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1222 const struct sctp_association *asoc, 1223 struct sctp_chunk *init, 1224 sctp_cmd_seq_t *commands) 1225 { 1226 struct sctp_transport *new_addr, *addr; 1227 struct list_head *pos, *pos2; 1228 int found; 1229 1230 /* Implementor's Guide - Sectin 5.2.2 1231 * ... 1232 * Before responding the endpoint MUST check to see if the 1233 * unexpected INIT adds new addresses to the association. If new 1234 * addresses are added to the association, the endpoint MUST respond 1235 * with an ABORT.. 1236 */ 1237 1238 /* Search through all current addresses and make sure 1239 * we aren't adding any new ones. 1240 */ 1241 new_addr = NULL; 1242 found = 0; 1243 1244 list_for_each(pos, &new_asoc->peer.transport_addr_list) { 1245 new_addr = list_entry(pos, struct sctp_transport, transports); 1246 found = 0; 1247 list_for_each(pos2, &asoc->peer.transport_addr_list) { 1248 addr = list_entry(pos2, struct sctp_transport, 1249 transports); 1250 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1251 &addr->ipaddr)) { 1252 found = 1; 1253 break; 1254 } 1255 } 1256 if (!found) 1257 break; 1258 } 1259 1260 /* If a new address was added, ABORT the sender. */ 1261 if (!found && new_addr) { 1262 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1263 } 1264 1265 /* Return success if all addresses were found. */ 1266 return found; 1267 } 1268 1269 /* Populate the verification/tie tags based on overlapping INIT 1270 * scenario. 1271 * 1272 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1273 */ 1274 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1275 const struct sctp_association *asoc) 1276 { 1277 switch (asoc->state) { 1278 1279 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1280 1281 case SCTP_STATE_COOKIE_WAIT: 1282 new_asoc->c.my_vtag = asoc->c.my_vtag; 1283 new_asoc->c.my_ttag = asoc->c.my_vtag; 1284 new_asoc->c.peer_ttag = 0; 1285 break; 1286 1287 case SCTP_STATE_COOKIE_ECHOED: 1288 new_asoc->c.my_vtag = asoc->c.my_vtag; 1289 new_asoc->c.my_ttag = asoc->c.my_vtag; 1290 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1291 break; 1292 1293 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1294 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1295 */ 1296 default: 1297 new_asoc->c.my_ttag = asoc->c.my_vtag; 1298 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1299 break; 1300 } 1301 1302 /* Other parameters for the endpoint SHOULD be copied from the 1303 * existing parameters of the association (e.g. number of 1304 * outbound streams) into the INIT ACK and cookie. 1305 */ 1306 new_asoc->rwnd = asoc->rwnd; 1307 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1308 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1309 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1310 } 1311 1312 static void sctp_auth_params_populate(struct sctp_association *new_asoc, 1313 const struct sctp_association *asoc) 1314 { 1315 /* Only perform this if AUTH extension is enabled */ 1316 if (!sctp_auth_enable) 1317 return; 1318 1319 /* We need to provide the same parameter information as 1320 * was in the original INIT. This means that we need to copy 1321 * the HMACS, CHUNKS, and RANDOM parameter from the original 1322 * assocaition. 1323 */ 1324 memcpy(new_asoc->c.auth_random, asoc->c.auth_random, 1325 sizeof(asoc->c.auth_random)); 1326 memcpy(new_asoc->c.auth_hmacs, asoc->c.auth_hmacs, 1327 sizeof(asoc->c.auth_hmacs)); 1328 memcpy(new_asoc->c.auth_chunks, asoc->c.auth_chunks, 1329 sizeof(asoc->c.auth_chunks)); 1330 } 1331 1332 /* 1333 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1334 * handling action. 1335 * 1336 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1337 * 1338 * Returns value representing action to be taken. These action values 1339 * correspond to Action/Description values in RFC 2960, Table 2. 1340 */ 1341 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1342 const struct sctp_association *asoc) 1343 { 1344 /* In this case, the peer may have restarted. */ 1345 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1346 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1347 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1348 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1349 return 'A'; 1350 1351 /* Collision case B. */ 1352 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1353 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1354 (0 == asoc->c.peer_vtag))) { 1355 return 'B'; 1356 } 1357 1358 /* Collision case D. */ 1359 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1360 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1361 return 'D'; 1362 1363 /* Collision case C. */ 1364 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1365 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1366 (0 == new_asoc->c.my_ttag) && 1367 (0 == new_asoc->c.peer_ttag)) 1368 return 'C'; 1369 1370 /* No match to any of the special cases; discard this packet. */ 1371 return 'E'; 1372 } 1373 1374 /* Common helper routine for both duplicate and simulataneous INIT 1375 * chunk handling. 1376 */ 1377 static sctp_disposition_t sctp_sf_do_unexpected_init( 1378 const struct sctp_endpoint *ep, 1379 const struct sctp_association *asoc, 1380 const sctp_subtype_t type, 1381 void *arg, sctp_cmd_seq_t *commands) 1382 { 1383 sctp_disposition_t retval; 1384 struct sctp_chunk *chunk = arg; 1385 struct sctp_chunk *repl; 1386 struct sctp_association *new_asoc; 1387 struct sctp_chunk *err_chunk; 1388 struct sctp_packet *packet; 1389 sctp_unrecognized_param_t *unk_param; 1390 int len; 1391 1392 /* 6.10 Bundling 1393 * An endpoint MUST NOT bundle INIT, INIT ACK or 1394 * SHUTDOWN COMPLETE with any other chunks. 1395 * 1396 * IG Section 2.11.2 1397 * Furthermore, we require that the receiver of an INIT chunk MUST 1398 * enforce these rules by silently discarding an arriving packet 1399 * with an INIT chunk that is bundled with other chunks. 1400 */ 1401 if (!chunk->singleton) 1402 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1403 1404 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1405 * Tag. 1406 */ 1407 if (chunk->sctp_hdr->vtag != 0) 1408 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1409 1410 /* Make sure that the INIT chunk has a valid length. 1411 * In this case, we generate a protocol violation since we have 1412 * an association established. 1413 */ 1414 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1415 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1416 commands); 1417 /* Grab the INIT header. */ 1418 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1419 1420 /* Tag the variable length parameters. */ 1421 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1422 1423 /* Verify the INIT chunk before processing it. */ 1424 err_chunk = NULL; 1425 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1426 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1427 &err_chunk)) { 1428 /* This chunk contains fatal error. It is to be discarded. 1429 * Send an ABORT, with causes if there is any. 1430 */ 1431 if (err_chunk) { 1432 packet = sctp_abort_pkt_new(ep, asoc, arg, 1433 (__u8 *)(err_chunk->chunk_hdr) + 1434 sizeof(sctp_chunkhdr_t), 1435 ntohs(err_chunk->chunk_hdr->length) - 1436 sizeof(sctp_chunkhdr_t)); 1437 1438 if (packet) { 1439 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1440 SCTP_PACKET(packet)); 1441 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1442 retval = SCTP_DISPOSITION_CONSUME; 1443 } else { 1444 retval = SCTP_DISPOSITION_NOMEM; 1445 } 1446 goto cleanup; 1447 } else { 1448 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1449 commands); 1450 } 1451 } 1452 1453 /* 1454 * Other parameters for the endpoint SHOULD be copied from the 1455 * existing parameters of the association (e.g. number of 1456 * outbound streams) into the INIT ACK and cookie. 1457 * FIXME: We are copying parameters from the endpoint not the 1458 * association. 1459 */ 1460 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1461 if (!new_asoc) 1462 goto nomem; 1463 1464 /* In the outbound INIT ACK the endpoint MUST copy its current 1465 * Verification Tag and Peers Verification tag into a reserved 1466 * place (local tie-tag and per tie-tag) within the state cookie. 1467 */ 1468 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1469 sctp_source(chunk), 1470 (sctp_init_chunk_t *)chunk->chunk_hdr, 1471 GFP_ATOMIC)) 1472 goto nomem; 1473 1474 /* Make sure no new addresses are being added during the 1475 * restart. Do not do this check for COOKIE-WAIT state, 1476 * since there are no peer addresses to check against. 1477 * Upon return an ABORT will have been sent if needed. 1478 */ 1479 if (!sctp_state(asoc, COOKIE_WAIT)) { 1480 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1481 commands)) { 1482 retval = SCTP_DISPOSITION_CONSUME; 1483 goto nomem_retval; 1484 } 1485 } 1486 1487 sctp_tietags_populate(new_asoc, asoc); 1488 1489 sctp_auth_params_populate(new_asoc, asoc); 1490 1491 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1492 1493 /* If there are errors need to be reported for unknown parameters, 1494 * make sure to reserve enough room in the INIT ACK for them. 1495 */ 1496 len = 0; 1497 if (err_chunk) { 1498 len = ntohs(err_chunk->chunk_hdr->length) - 1499 sizeof(sctp_chunkhdr_t); 1500 } 1501 1502 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 1503 goto nomem; 1504 1505 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1506 if (!repl) 1507 goto nomem; 1508 1509 /* If there are errors need to be reported for unknown parameters, 1510 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1511 * parameter. 1512 */ 1513 if (err_chunk) { 1514 /* Get the "Unrecognized parameter" parameter(s) out of the 1515 * ERROR chunk generated by sctp_verify_init(). Since the 1516 * error cause code for "unknown parameter" and the 1517 * "Unrecognized parameter" type is the same, we can 1518 * construct the parameters in INIT ACK by copying the 1519 * ERROR causes over. 1520 */ 1521 unk_param = (sctp_unrecognized_param_t *) 1522 ((__u8 *)(err_chunk->chunk_hdr) + 1523 sizeof(sctp_chunkhdr_t)); 1524 /* Replace the cause code with the "Unrecognized parameter" 1525 * parameter type. 1526 */ 1527 sctp_addto_chunk(repl, len, unk_param); 1528 } 1529 1530 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1531 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1532 1533 /* 1534 * Note: After sending out INIT ACK with the State Cookie parameter, 1535 * "Z" MUST NOT allocate any resources for this new association. 1536 * Otherwise, "Z" will be vulnerable to resource attacks. 1537 */ 1538 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1539 retval = SCTP_DISPOSITION_CONSUME; 1540 1541 return retval; 1542 1543 nomem: 1544 retval = SCTP_DISPOSITION_NOMEM; 1545 nomem_retval: 1546 if (new_asoc) 1547 sctp_association_free(new_asoc); 1548 cleanup: 1549 if (err_chunk) 1550 sctp_chunk_free(err_chunk); 1551 return retval; 1552 } 1553 1554 /* 1555 * Handle simultanous INIT. 1556 * This means we started an INIT and then we got an INIT request from 1557 * our peer. 1558 * 1559 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1560 * This usually indicates an initialization collision, i.e., each 1561 * endpoint is attempting, at about the same time, to establish an 1562 * association with the other endpoint. 1563 * 1564 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1565 * endpoint MUST respond with an INIT ACK using the same parameters it 1566 * sent in its original INIT chunk (including its Verification Tag, 1567 * unchanged). These original parameters are combined with those from the 1568 * newly received INIT chunk. The endpoint shall also generate a State 1569 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1570 * INIT to calculate the State Cookie. 1571 * 1572 * After that, the endpoint MUST NOT change its state, the T1-init 1573 * timer shall be left running and the corresponding TCB MUST NOT be 1574 * destroyed. The normal procedures for handling State Cookies when 1575 * a TCB exists will resolve the duplicate INITs to a single association. 1576 * 1577 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1578 * its Tie-Tags with the Tag information of itself and its peer (see 1579 * section 5.2.2 for a description of the Tie-Tags). 1580 * 1581 * Verification Tag: Not explicit, but an INIT can not have a valid 1582 * verification tag, so we skip the check. 1583 * 1584 * Inputs 1585 * (endpoint, asoc, chunk) 1586 * 1587 * Outputs 1588 * (asoc, reply_msg, msg_up, timers, counters) 1589 * 1590 * The return value is the disposition of the chunk. 1591 */ 1592 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1593 const struct sctp_association *asoc, 1594 const sctp_subtype_t type, 1595 void *arg, 1596 sctp_cmd_seq_t *commands) 1597 { 1598 /* Call helper to do the real work for both simulataneous and 1599 * duplicate INIT chunk handling. 1600 */ 1601 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1602 } 1603 1604 /* 1605 * Handle duplicated INIT messages. These are usually delayed 1606 * restransmissions. 1607 * 1608 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1609 * COOKIE-ECHOED and COOKIE-WAIT 1610 * 1611 * Unless otherwise stated, upon reception of an unexpected INIT for 1612 * this association, the endpoint shall generate an INIT ACK with a 1613 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1614 * current Verification Tag and peer's Verification Tag into a reserved 1615 * place within the state cookie. We shall refer to these locations as 1616 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1617 * containing this INIT ACK MUST carry a Verification Tag value equal to 1618 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1619 * MUST contain a new Initiation Tag (randomly generated see Section 1620 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1621 * existing parameters of the association (e.g. number of outbound 1622 * streams) into the INIT ACK and cookie. 1623 * 1624 * After sending out the INIT ACK, the endpoint shall take no further 1625 * actions, i.e., the existing association, including its current state, 1626 * and the corresponding TCB MUST NOT be changed. 1627 * 1628 * Note: Only when a TCB exists and the association is not in a COOKIE- 1629 * WAIT state are the Tie-Tags populated. For a normal association INIT 1630 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1631 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1632 * State Cookie are populated as specified in section 5.2.1. 1633 * 1634 * Verification Tag: Not specified, but an INIT has no way of knowing 1635 * what the verification tag could be, so we ignore it. 1636 * 1637 * Inputs 1638 * (endpoint, asoc, chunk) 1639 * 1640 * Outputs 1641 * (asoc, reply_msg, msg_up, timers, counters) 1642 * 1643 * The return value is the disposition of the chunk. 1644 */ 1645 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1646 const struct sctp_association *asoc, 1647 const sctp_subtype_t type, 1648 void *arg, 1649 sctp_cmd_seq_t *commands) 1650 { 1651 /* Call helper to do the real work for both simulataneous and 1652 * duplicate INIT chunk handling. 1653 */ 1654 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1655 } 1656 1657 1658 /* 1659 * Unexpected INIT-ACK handler. 1660 * 1661 * Section 5.2.3 1662 * If an INIT ACK received by an endpoint in any state other than the 1663 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1664 * An unexpected INIT ACK usually indicates the processing of an old or 1665 * duplicated INIT chunk. 1666 */ 1667 sctp_disposition_t sctp_sf_do_5_2_3_initack(const struct sctp_endpoint *ep, 1668 const struct sctp_association *asoc, 1669 const sctp_subtype_t type, 1670 void *arg, sctp_cmd_seq_t *commands) 1671 { 1672 /* Per the above section, we'll discard the chunk if we have an 1673 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1674 */ 1675 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 1676 return sctp_sf_ootb(ep, asoc, type, arg, commands); 1677 else 1678 return sctp_sf_discard_chunk(ep, asoc, type, arg, commands); 1679 } 1680 1681 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1682 * 1683 * Section 5.2.4 1684 * A) In this case, the peer may have restarted. 1685 */ 1686 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1687 const struct sctp_association *asoc, 1688 struct sctp_chunk *chunk, 1689 sctp_cmd_seq_t *commands, 1690 struct sctp_association *new_asoc) 1691 { 1692 sctp_init_chunk_t *peer_init; 1693 struct sctp_ulpevent *ev; 1694 struct sctp_chunk *repl; 1695 struct sctp_chunk *err; 1696 sctp_disposition_t disposition; 1697 1698 /* new_asoc is a brand-new association, so these are not yet 1699 * side effects--it is safe to run them here. 1700 */ 1701 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1702 1703 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1704 sctp_source(chunk), peer_init, 1705 GFP_ATOMIC)) 1706 goto nomem; 1707 1708 /* Make sure no new addresses are being added during the 1709 * restart. Though this is a pretty complicated attack 1710 * since you'd have to get inside the cookie. 1711 */ 1712 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1713 return SCTP_DISPOSITION_CONSUME; 1714 } 1715 1716 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1717 * the peer has restarted (Action A), it MUST NOT setup a new 1718 * association but instead resend the SHUTDOWN ACK and send an ERROR 1719 * chunk with a "Cookie Received while Shutting Down" error cause to 1720 * its peer. 1721 */ 1722 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1723 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1724 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1725 chunk, commands); 1726 if (SCTP_DISPOSITION_NOMEM == disposition) 1727 goto nomem; 1728 1729 err = sctp_make_op_error(asoc, chunk, 1730 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1731 NULL, 0); 1732 if (err) 1733 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1734 SCTP_CHUNK(err)); 1735 1736 return SCTP_DISPOSITION_CONSUME; 1737 } 1738 1739 /* For now, fail any unsent/unacked data. Consider the optional 1740 * choice of resending of this data. 1741 */ 1742 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1743 1744 repl = sctp_make_cookie_ack(new_asoc, chunk); 1745 if (!repl) 1746 goto nomem; 1747 1748 /* Report association restart to upper layer. */ 1749 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1750 new_asoc->c.sinit_num_ostreams, 1751 new_asoc->c.sinit_max_instreams, 1752 NULL, GFP_ATOMIC); 1753 if (!ev) 1754 goto nomem_ev; 1755 1756 /* Update the content of current association. */ 1757 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1758 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1759 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1760 return SCTP_DISPOSITION_CONSUME; 1761 1762 nomem_ev: 1763 sctp_chunk_free(repl); 1764 nomem: 1765 return SCTP_DISPOSITION_NOMEM; 1766 } 1767 1768 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1769 * 1770 * Section 5.2.4 1771 * B) In this case, both sides may be attempting to start an association 1772 * at about the same time but the peer endpoint started its INIT 1773 * after responding to the local endpoint's INIT 1774 */ 1775 /* This case represents an initialization collision. */ 1776 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1777 const struct sctp_association *asoc, 1778 struct sctp_chunk *chunk, 1779 sctp_cmd_seq_t *commands, 1780 struct sctp_association *new_asoc) 1781 { 1782 sctp_init_chunk_t *peer_init; 1783 struct sctp_chunk *repl; 1784 1785 /* new_asoc is a brand-new association, so these are not yet 1786 * side effects--it is safe to run them here. 1787 */ 1788 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1789 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1790 sctp_source(chunk), peer_init, 1791 GFP_ATOMIC)) 1792 goto nomem; 1793 1794 /* Update the content of current association. */ 1795 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1796 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1797 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1798 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1799 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1800 1801 repl = sctp_make_cookie_ack(new_asoc, chunk); 1802 if (!repl) 1803 goto nomem; 1804 1805 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1806 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1807 1808 /* RFC 2960 5.1 Normal Establishment of an Association 1809 * 1810 * D) IMPLEMENTATION NOTE: An implementation may choose to 1811 * send the Communication Up notification to the SCTP user 1812 * upon reception of a valid COOKIE ECHO chunk. 1813 * 1814 * Sadly, this needs to be implemented as a side-effect, because 1815 * we are not guaranteed to have set the association id of the real 1816 * association and so these notifications need to be delayed until 1817 * the association id is allocated. 1818 */ 1819 1820 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1821 1822 /* Sockets API Draft Section 5.3.1.6 1823 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1824 * delivers this notification to inform the application that of the 1825 * peers requested adaptation layer. 1826 * 1827 * This also needs to be done as a side effect for the same reason as 1828 * above. 1829 */ 1830 if (asoc->peer.adaptation_ind) 1831 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1832 1833 return SCTP_DISPOSITION_CONSUME; 1834 1835 nomem: 1836 return SCTP_DISPOSITION_NOMEM; 1837 } 1838 1839 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1840 * 1841 * Section 5.2.4 1842 * C) In this case, the local endpoint's cookie has arrived late. 1843 * Before it arrived, the local endpoint sent an INIT and received an 1844 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1845 * but a new tag of its own. 1846 */ 1847 /* This case represents an initialization collision. */ 1848 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1849 const struct sctp_association *asoc, 1850 struct sctp_chunk *chunk, 1851 sctp_cmd_seq_t *commands, 1852 struct sctp_association *new_asoc) 1853 { 1854 /* The cookie should be silently discarded. 1855 * The endpoint SHOULD NOT change states and should leave 1856 * any timers running. 1857 */ 1858 return SCTP_DISPOSITION_DISCARD; 1859 } 1860 1861 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1862 * 1863 * Section 5.2.4 1864 * 1865 * D) When both local and remote tags match the endpoint should always 1866 * enter the ESTABLISHED state, if it has not already done so. 1867 */ 1868 /* This case represents an initialization collision. */ 1869 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1870 const struct sctp_association *asoc, 1871 struct sctp_chunk *chunk, 1872 sctp_cmd_seq_t *commands, 1873 struct sctp_association *new_asoc) 1874 { 1875 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1876 struct sctp_chunk *repl; 1877 1878 /* Clarification from Implementor's Guide: 1879 * D) When both local and remote tags match the endpoint should 1880 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1881 * It should stop any cookie timer that may be running and send 1882 * a COOKIE ACK. 1883 */ 1884 1885 /* Don't accidentally move back into established state. */ 1886 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1887 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1888 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1889 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1890 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1891 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1892 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1893 SCTP_NULL()); 1894 1895 /* RFC 2960 5.1 Normal Establishment of an Association 1896 * 1897 * D) IMPLEMENTATION NOTE: An implementation may choose 1898 * to send the Communication Up notification to the 1899 * SCTP user upon reception of a valid COOKIE 1900 * ECHO chunk. 1901 */ 1902 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1903 SCTP_COMM_UP, 0, 1904 asoc->c.sinit_num_ostreams, 1905 asoc->c.sinit_max_instreams, 1906 NULL, GFP_ATOMIC); 1907 if (!ev) 1908 goto nomem; 1909 1910 /* Sockets API Draft Section 5.3.1.6 1911 * When a peer sends a Adaptation Layer Indication parameter, 1912 * SCTP delivers this notification to inform the application 1913 * that of the peers requested adaptation layer. 1914 */ 1915 if (asoc->peer.adaptation_ind) { 1916 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1917 GFP_ATOMIC); 1918 if (!ai_ev) 1919 goto nomem; 1920 1921 } 1922 } 1923 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1924 1925 repl = sctp_make_cookie_ack(new_asoc, chunk); 1926 if (!repl) 1927 goto nomem; 1928 1929 if (ev) 1930 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1931 SCTP_ULPEVENT(ev)); 1932 if (ai_ev) 1933 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1934 SCTP_ULPEVENT(ai_ev)); 1935 1936 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1937 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1938 1939 return SCTP_DISPOSITION_CONSUME; 1940 1941 nomem: 1942 if (ai_ev) 1943 sctp_ulpevent_free(ai_ev); 1944 if (ev) 1945 sctp_ulpevent_free(ev); 1946 return SCTP_DISPOSITION_NOMEM; 1947 } 1948 1949 /* 1950 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1951 * chunk was retransmitted and then delayed in the network. 1952 * 1953 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1954 * 1955 * Verification Tag: None. Do cookie validation. 1956 * 1957 * Inputs 1958 * (endpoint, asoc, chunk) 1959 * 1960 * Outputs 1961 * (asoc, reply_msg, msg_up, timers, counters) 1962 * 1963 * The return value is the disposition of the chunk. 1964 */ 1965 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1966 const struct sctp_association *asoc, 1967 const sctp_subtype_t type, 1968 void *arg, 1969 sctp_cmd_seq_t *commands) 1970 { 1971 sctp_disposition_t retval; 1972 struct sctp_chunk *chunk = arg; 1973 struct sctp_association *new_asoc; 1974 int error = 0; 1975 char action; 1976 struct sctp_chunk *err_chk_p; 1977 1978 /* Make sure that the chunk has a valid length from the protocol 1979 * perspective. In this case check to make sure we have at least 1980 * enough for the chunk header. Cookie length verification is 1981 * done later. 1982 */ 1983 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1984 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1985 commands); 1986 1987 /* "Decode" the chunk. We have no optional parameters so we 1988 * are in good shape. 1989 */ 1990 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1991 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1992 sizeof(sctp_chunkhdr_t))) 1993 goto nomem; 1994 1995 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1996 * of a duplicate COOKIE ECHO match the Verification Tags of the 1997 * current association, consider the State Cookie valid even if 1998 * the lifespan is exceeded. 1999 */ 2000 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2001 &err_chk_p); 2002 2003 /* FIXME: 2004 * If the re-build failed, what is the proper error path 2005 * from here? 2006 * 2007 * [We should abort the association. --piggy] 2008 */ 2009 if (!new_asoc) { 2010 /* FIXME: Several errors are possible. A bad cookie should 2011 * be silently discarded, but think about logging it too. 2012 */ 2013 switch (error) { 2014 case -SCTP_IERROR_NOMEM: 2015 goto nomem; 2016 2017 case -SCTP_IERROR_STALE_COOKIE: 2018 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 2019 err_chk_p); 2020 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2021 case -SCTP_IERROR_BAD_SIG: 2022 default: 2023 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2024 } 2025 } 2026 2027 /* Compare the tie_tag in cookie with the verification tag of 2028 * current association. 2029 */ 2030 action = sctp_tietags_compare(new_asoc, asoc); 2031 2032 switch (action) { 2033 case 'A': /* Association restart. */ 2034 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 2035 new_asoc); 2036 break; 2037 2038 case 'B': /* Collision case B. */ 2039 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 2040 new_asoc); 2041 break; 2042 2043 case 'C': /* Collision case C. */ 2044 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 2045 new_asoc); 2046 break; 2047 2048 case 'D': /* Collision case D. */ 2049 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 2050 new_asoc); 2051 break; 2052 2053 default: /* Discard packet for all others. */ 2054 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2055 break; 2056 } 2057 2058 /* Delete the tempory new association. */ 2059 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2060 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2061 2062 return retval; 2063 2064 nomem: 2065 return SCTP_DISPOSITION_NOMEM; 2066 } 2067 2068 /* 2069 * Process an ABORT. (SHUTDOWN-PENDING state) 2070 * 2071 * See sctp_sf_do_9_1_abort(). 2072 */ 2073 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2074 const struct sctp_endpoint *ep, 2075 const struct sctp_association *asoc, 2076 const sctp_subtype_t type, 2077 void *arg, 2078 sctp_cmd_seq_t *commands) 2079 { 2080 struct sctp_chunk *chunk = arg; 2081 2082 if (!sctp_vtag_verify_either(chunk, asoc)) 2083 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2084 2085 /* Make sure that the ABORT chunk has a valid length. 2086 * Since this is an ABORT chunk, we have to discard it 2087 * because of the following text: 2088 * RFC 2960, Section 3.3.7 2089 * If an endpoint receives an ABORT with a format error or for an 2090 * association that doesn't exist, it MUST silently discard it. 2091 * Becasue the length is "invalid", we can't really discard just 2092 * as we do not know its true length. So, to be safe, discard the 2093 * packet. 2094 */ 2095 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2096 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2097 2098 /* Stop the T5-shutdown guard timer. */ 2099 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2100 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2101 2102 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2103 } 2104 2105 /* 2106 * Process an ABORT. (SHUTDOWN-SENT state) 2107 * 2108 * See sctp_sf_do_9_1_abort(). 2109 */ 2110 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 2111 const struct sctp_association *asoc, 2112 const sctp_subtype_t type, 2113 void *arg, 2114 sctp_cmd_seq_t *commands) 2115 { 2116 struct sctp_chunk *chunk = arg; 2117 2118 if (!sctp_vtag_verify_either(chunk, asoc)) 2119 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2120 2121 /* Make sure that the ABORT chunk has a valid length. 2122 * Since this is an ABORT chunk, we have to discard it 2123 * because of the following text: 2124 * RFC 2960, Section 3.3.7 2125 * If an endpoint receives an ABORT with a format error or for an 2126 * association that doesn't exist, it MUST silently discard it. 2127 * Becasue the length is "invalid", we can't really discard just 2128 * as we do not know its true length. So, to be safe, discard the 2129 * packet. 2130 */ 2131 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2132 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2133 2134 /* Stop the T2-shutdown timer. */ 2135 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2136 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2137 2138 /* Stop the T5-shutdown guard timer. */ 2139 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2140 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2141 2142 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2143 } 2144 2145 /* 2146 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2147 * 2148 * See sctp_sf_do_9_1_abort(). 2149 */ 2150 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2151 const struct sctp_endpoint *ep, 2152 const struct sctp_association *asoc, 2153 const sctp_subtype_t type, 2154 void *arg, 2155 sctp_cmd_seq_t *commands) 2156 { 2157 /* The same T2 timer, so we should be able to use 2158 * common function with the SHUTDOWN-SENT state. 2159 */ 2160 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2161 } 2162 2163 /* 2164 * Handle an Error received in COOKIE_ECHOED state. 2165 * 2166 * Only handle the error type of stale COOKIE Error, the other errors will 2167 * be ignored. 2168 * 2169 * Inputs 2170 * (endpoint, asoc, chunk) 2171 * 2172 * Outputs 2173 * (asoc, reply_msg, msg_up, timers, counters) 2174 * 2175 * The return value is the disposition of the chunk. 2176 */ 2177 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2178 const struct sctp_association *asoc, 2179 const sctp_subtype_t type, 2180 void *arg, 2181 sctp_cmd_seq_t *commands) 2182 { 2183 struct sctp_chunk *chunk = arg; 2184 sctp_errhdr_t *err; 2185 2186 if (!sctp_vtag_verify(chunk, asoc)) 2187 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2188 2189 /* Make sure that the ERROR chunk has a valid length. 2190 * The parameter walking depends on this as well. 2191 */ 2192 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2193 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2194 commands); 2195 2196 /* Process the error here */ 2197 /* FUTURE FIXME: When PR-SCTP related and other optional 2198 * parms are emitted, this will have to change to handle multiple 2199 * errors. 2200 */ 2201 sctp_walk_errors(err, chunk->chunk_hdr) { 2202 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2203 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2204 arg, commands); 2205 } 2206 2207 /* It is possible to have malformed error causes, and that 2208 * will cause us to end the walk early. However, since 2209 * we are discarding the packet, there should be no adverse 2210 * affects. 2211 */ 2212 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2213 } 2214 2215 /* 2216 * Handle a Stale COOKIE Error 2217 * 2218 * Section: 5.2.6 Handle Stale COOKIE Error 2219 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2220 * one of the following three alternatives. 2221 * ... 2222 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2223 * Preservative parameter requesting an extension to the lifetime of 2224 * the State Cookie. When calculating the time extension, an 2225 * implementation SHOULD use the RTT information measured based on the 2226 * previous COOKIE ECHO / ERROR exchange, and should add no more 2227 * than 1 second beyond the measured RTT, due to long State Cookie 2228 * lifetimes making the endpoint more subject to a replay attack. 2229 * 2230 * Verification Tag: Not explicit, but safe to ignore. 2231 * 2232 * Inputs 2233 * (endpoint, asoc, chunk) 2234 * 2235 * Outputs 2236 * (asoc, reply_msg, msg_up, timers, counters) 2237 * 2238 * The return value is the disposition of the chunk. 2239 */ 2240 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2241 const struct sctp_association *asoc, 2242 const sctp_subtype_t type, 2243 void *arg, 2244 sctp_cmd_seq_t *commands) 2245 { 2246 struct sctp_chunk *chunk = arg; 2247 time_t stale; 2248 sctp_cookie_preserve_param_t bht; 2249 sctp_errhdr_t *err; 2250 struct sctp_chunk *reply; 2251 struct sctp_bind_addr *bp; 2252 int attempts = asoc->init_err_counter + 1; 2253 2254 if (attempts > asoc->max_init_attempts) { 2255 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2256 SCTP_ERROR(ETIMEDOUT)); 2257 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2258 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2259 return SCTP_DISPOSITION_DELETE_TCB; 2260 } 2261 2262 err = (sctp_errhdr_t *)(chunk->skb->data); 2263 2264 /* When calculating the time extension, an implementation 2265 * SHOULD use the RTT information measured based on the 2266 * previous COOKIE ECHO / ERROR exchange, and should add no 2267 * more than 1 second beyond the measured RTT, due to long 2268 * State Cookie lifetimes making the endpoint more subject to 2269 * a replay attack. 2270 * Measure of Staleness's unit is usec. (1/1000000 sec) 2271 * Suggested Cookie Life-span Increment's unit is msec. 2272 * (1/1000 sec) 2273 * In general, if you use the suggested cookie life, the value 2274 * found in the field of measure of staleness should be doubled 2275 * to give ample time to retransmit the new cookie and thus 2276 * yield a higher probability of success on the reattempt. 2277 */ 2278 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2279 stale = (stale * 2) / 1000; 2280 2281 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2282 bht.param_hdr.length = htons(sizeof(bht)); 2283 bht.lifespan_increment = htonl(stale); 2284 2285 /* Build that new INIT chunk. */ 2286 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2287 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2288 if (!reply) 2289 goto nomem; 2290 2291 sctp_addto_chunk(reply, sizeof(bht), &bht); 2292 2293 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2294 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2295 2296 /* Stop pending T3-rtx and heartbeat timers */ 2297 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2298 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2299 2300 /* Delete non-primary peer ip addresses since we are transitioning 2301 * back to the COOKIE-WAIT state 2302 */ 2303 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2304 2305 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2306 * resend 2307 */ 2308 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, 2309 SCTP_TRANSPORT(asoc->peer.primary_path)); 2310 2311 /* Cast away the const modifier, as we want to just 2312 * rerun it through as a sideffect. 2313 */ 2314 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2315 2316 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2317 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2318 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2319 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2320 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2321 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2322 2323 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2324 2325 return SCTP_DISPOSITION_CONSUME; 2326 2327 nomem: 2328 return SCTP_DISPOSITION_NOMEM; 2329 } 2330 2331 /* 2332 * Process an ABORT. 2333 * 2334 * Section: 9.1 2335 * After checking the Verification Tag, the receiving endpoint shall 2336 * remove the association from its record, and shall report the 2337 * termination to its upper layer. 2338 * 2339 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2340 * B) Rules for packet carrying ABORT: 2341 * 2342 * - The endpoint shall always fill in the Verification Tag field of the 2343 * outbound packet with the destination endpoint's tag value if it 2344 * is known. 2345 * 2346 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2347 * MUST follow the procedure described in Section 8.4. 2348 * 2349 * - The receiver MUST accept the packet if the Verification Tag 2350 * matches either its own tag, OR the tag of its peer. Otherwise, the 2351 * receiver MUST silently discard the packet and take no further 2352 * action. 2353 * 2354 * Inputs 2355 * (endpoint, asoc, chunk) 2356 * 2357 * Outputs 2358 * (asoc, reply_msg, msg_up, timers, counters) 2359 * 2360 * The return value is the disposition of the chunk. 2361 */ 2362 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2363 const struct sctp_association *asoc, 2364 const sctp_subtype_t type, 2365 void *arg, 2366 sctp_cmd_seq_t *commands) 2367 { 2368 struct sctp_chunk *chunk = arg; 2369 unsigned len; 2370 __be16 error = SCTP_ERROR_NO_ERROR; 2371 2372 if (!sctp_vtag_verify_either(chunk, asoc)) 2373 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2374 2375 /* Make sure that the ABORT chunk has a valid length. 2376 * Since this is an ABORT chunk, we have to discard it 2377 * because of the following text: 2378 * RFC 2960, Section 3.3.7 2379 * If an endpoint receives an ABORT with a format error or for an 2380 * association that doesn't exist, it MUST silently discard it. 2381 * Becasue the length is "invalid", we can't really discard just 2382 * as we do not know its true length. So, to be safe, discard the 2383 * packet. 2384 */ 2385 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2386 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2387 2388 /* See if we have an error cause code in the chunk. */ 2389 len = ntohs(chunk->chunk_hdr->length); 2390 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2391 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2392 2393 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2394 /* ASSOC_FAILED will DELETE_TCB. */ 2395 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2396 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2397 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2398 2399 return SCTP_DISPOSITION_ABORT; 2400 } 2401 2402 /* 2403 * Process an ABORT. (COOKIE-WAIT state) 2404 * 2405 * See sctp_sf_do_9_1_abort() above. 2406 */ 2407 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2408 const struct sctp_association *asoc, 2409 const sctp_subtype_t type, 2410 void *arg, 2411 sctp_cmd_seq_t *commands) 2412 { 2413 struct sctp_chunk *chunk = arg; 2414 unsigned len; 2415 __be16 error = SCTP_ERROR_NO_ERROR; 2416 2417 if (!sctp_vtag_verify_either(chunk, asoc)) 2418 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2419 2420 /* Make sure that the ABORT chunk has a valid length. 2421 * Since this is an ABORT chunk, we have to discard it 2422 * because of the following text: 2423 * RFC 2960, Section 3.3.7 2424 * If an endpoint receives an ABORT with a format error or for an 2425 * association that doesn't exist, it MUST silently discard it. 2426 * Becasue the length is "invalid", we can't really discard just 2427 * as we do not know its true length. So, to be safe, discard the 2428 * packet. 2429 */ 2430 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2431 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2432 2433 /* See if we have an error cause code in the chunk. */ 2434 len = ntohs(chunk->chunk_hdr->length); 2435 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2436 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2437 2438 return sctp_stop_t1_and_abort(commands, error, ECONNREFUSED, asoc, 2439 chunk->transport); 2440 } 2441 2442 /* 2443 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2444 */ 2445 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2446 const struct sctp_association *asoc, 2447 const sctp_subtype_t type, 2448 void *arg, 2449 sctp_cmd_seq_t *commands) 2450 { 2451 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, 2452 ENOPROTOOPT, asoc, 2453 (struct sctp_transport *)arg); 2454 } 2455 2456 /* 2457 * Process an ABORT. (COOKIE-ECHOED state) 2458 */ 2459 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2460 const struct sctp_association *asoc, 2461 const sctp_subtype_t type, 2462 void *arg, 2463 sctp_cmd_seq_t *commands) 2464 { 2465 /* There is a single T1 timer, so we should be able to use 2466 * common function with the COOKIE-WAIT state. 2467 */ 2468 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2469 } 2470 2471 /* 2472 * Stop T1 timer and abort association with "INIT failed". 2473 * 2474 * This is common code called by several sctp_sf_*_abort() functions above. 2475 */ 2476 static sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2477 __be16 error, int sk_err, 2478 const struct sctp_association *asoc, 2479 struct sctp_transport *transport) 2480 { 2481 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2482 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2483 SCTP_STATE(SCTP_STATE_CLOSED)); 2484 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2485 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2486 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2487 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2488 /* CMD_INIT_FAILED will DELETE_TCB. */ 2489 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2490 SCTP_PERR(error)); 2491 return SCTP_DISPOSITION_ABORT; 2492 } 2493 2494 /* 2495 * sctp_sf_do_9_2_shut 2496 * 2497 * Section: 9.2 2498 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2499 * - enter the SHUTDOWN-RECEIVED state, 2500 * 2501 * - stop accepting new data from its SCTP user 2502 * 2503 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2504 * that all its outstanding DATA chunks have been received by the 2505 * SHUTDOWN sender. 2506 * 2507 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2508 * send a SHUTDOWN in response to a ULP request. And should discard 2509 * subsequent SHUTDOWN chunks. 2510 * 2511 * If there are still outstanding DATA chunks left, the SHUTDOWN 2512 * receiver shall continue to follow normal data transmission 2513 * procedures defined in Section 6 until all outstanding DATA chunks 2514 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2515 * new data from its SCTP user. 2516 * 2517 * Verification Tag: 8.5 Verification Tag [Normal verification] 2518 * 2519 * Inputs 2520 * (endpoint, asoc, chunk) 2521 * 2522 * Outputs 2523 * (asoc, reply_msg, msg_up, timers, counters) 2524 * 2525 * The return value is the disposition of the chunk. 2526 */ 2527 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2528 const struct sctp_association *asoc, 2529 const sctp_subtype_t type, 2530 void *arg, 2531 sctp_cmd_seq_t *commands) 2532 { 2533 struct sctp_chunk *chunk = arg; 2534 sctp_shutdownhdr_t *sdh; 2535 sctp_disposition_t disposition; 2536 struct sctp_ulpevent *ev; 2537 2538 if (!sctp_vtag_verify(chunk, asoc)) 2539 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2540 2541 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2542 if (!sctp_chunk_length_valid(chunk, 2543 sizeof(struct sctp_shutdown_chunk_t))) 2544 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2545 commands); 2546 2547 /* Convert the elaborate header. */ 2548 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2549 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2550 chunk->subh.shutdown_hdr = sdh; 2551 2552 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2553 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2554 * inform the application that it should cease sending data. 2555 */ 2556 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2557 if (!ev) { 2558 disposition = SCTP_DISPOSITION_NOMEM; 2559 goto out; 2560 } 2561 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2562 2563 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2564 * - enter the SHUTDOWN-RECEIVED state, 2565 * - stop accepting new data from its SCTP user 2566 * 2567 * [This is implicit in the new state.] 2568 */ 2569 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2570 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2571 disposition = SCTP_DISPOSITION_CONSUME; 2572 2573 if (sctp_outq_is_empty(&asoc->outqueue)) { 2574 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2575 arg, commands); 2576 } 2577 2578 if (SCTP_DISPOSITION_NOMEM == disposition) 2579 goto out; 2580 2581 /* - verify, by checking the Cumulative TSN Ack field of the 2582 * chunk, that all its outstanding DATA chunks have been 2583 * received by the SHUTDOWN sender. 2584 */ 2585 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2586 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2587 2588 out: 2589 return disposition; 2590 } 2591 2592 /* RFC 2960 9.2 2593 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2594 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2595 * transport addresses (either in the IP addresses or in the INIT chunk) 2596 * that belong to this association, it should discard the INIT chunk and 2597 * retransmit the SHUTDOWN ACK chunk. 2598 */ 2599 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2600 const struct sctp_association *asoc, 2601 const sctp_subtype_t type, 2602 void *arg, 2603 sctp_cmd_seq_t *commands) 2604 { 2605 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2606 struct sctp_chunk *reply; 2607 2608 /* Make sure that the chunk has a valid length */ 2609 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2610 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2611 commands); 2612 2613 /* Since we are not going to really process this INIT, there 2614 * is no point in verifying chunk boundries. Just generate 2615 * the SHUTDOWN ACK. 2616 */ 2617 reply = sctp_make_shutdown_ack(asoc, chunk); 2618 if (NULL == reply) 2619 goto nomem; 2620 2621 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2622 * the T2-SHUTDOWN timer. 2623 */ 2624 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2625 2626 /* and restart the T2-shutdown timer. */ 2627 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2628 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2629 2630 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2631 2632 return SCTP_DISPOSITION_CONSUME; 2633 nomem: 2634 return SCTP_DISPOSITION_NOMEM; 2635 } 2636 2637 /* 2638 * sctp_sf_do_ecn_cwr 2639 * 2640 * Section: Appendix A: Explicit Congestion Notification 2641 * 2642 * CWR: 2643 * 2644 * RFC 2481 details a specific bit for a sender to send in the header of 2645 * its next outbound TCP segment to indicate to its peer that it has 2646 * reduced its congestion window. This is termed the CWR bit. For 2647 * SCTP the same indication is made by including the CWR chunk. 2648 * This chunk contains one data element, i.e. the TSN number that 2649 * was sent in the ECNE chunk. This element represents the lowest 2650 * TSN number in the datagram that was originally marked with the 2651 * CE bit. 2652 * 2653 * Verification Tag: 8.5 Verification Tag [Normal verification] 2654 * Inputs 2655 * (endpoint, asoc, chunk) 2656 * 2657 * Outputs 2658 * (asoc, reply_msg, msg_up, timers, counters) 2659 * 2660 * The return value is the disposition of the chunk. 2661 */ 2662 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2663 const struct sctp_association *asoc, 2664 const sctp_subtype_t type, 2665 void *arg, 2666 sctp_cmd_seq_t *commands) 2667 { 2668 sctp_cwrhdr_t *cwr; 2669 struct sctp_chunk *chunk = arg; 2670 u32 lowest_tsn; 2671 2672 if (!sctp_vtag_verify(chunk, asoc)) 2673 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2674 2675 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2676 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2677 commands); 2678 2679 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2680 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2681 2682 lowest_tsn = ntohl(cwr->lowest_tsn); 2683 2684 /* Does this CWR ack the last sent congestion notification? */ 2685 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2686 /* Stop sending ECNE. */ 2687 sctp_add_cmd_sf(commands, 2688 SCTP_CMD_ECN_CWR, 2689 SCTP_U32(lowest_tsn)); 2690 } 2691 return SCTP_DISPOSITION_CONSUME; 2692 } 2693 2694 /* 2695 * sctp_sf_do_ecne 2696 * 2697 * Section: Appendix A: Explicit Congestion Notification 2698 * 2699 * ECN-Echo 2700 * 2701 * RFC 2481 details a specific bit for a receiver to send back in its 2702 * TCP acknowledgements to notify the sender of the Congestion 2703 * Experienced (CE) bit having arrived from the network. For SCTP this 2704 * same indication is made by including the ECNE chunk. This chunk 2705 * contains one data element, i.e. the lowest TSN associated with the IP 2706 * datagram marked with the CE bit..... 2707 * 2708 * Verification Tag: 8.5 Verification Tag [Normal verification] 2709 * Inputs 2710 * (endpoint, asoc, chunk) 2711 * 2712 * Outputs 2713 * (asoc, reply_msg, msg_up, timers, counters) 2714 * 2715 * The return value is the disposition of the chunk. 2716 */ 2717 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2718 const struct sctp_association *asoc, 2719 const sctp_subtype_t type, 2720 void *arg, 2721 sctp_cmd_seq_t *commands) 2722 { 2723 sctp_ecnehdr_t *ecne; 2724 struct sctp_chunk *chunk = arg; 2725 2726 if (!sctp_vtag_verify(chunk, asoc)) 2727 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2728 2729 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2730 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2731 commands); 2732 2733 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2734 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2735 2736 /* If this is a newer ECNE than the last CWR packet we sent out */ 2737 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2738 SCTP_U32(ntohl(ecne->lowest_tsn))); 2739 2740 return SCTP_DISPOSITION_CONSUME; 2741 } 2742 2743 /* 2744 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2745 * 2746 * The SCTP endpoint MUST always acknowledge the reception of each valid 2747 * DATA chunk. 2748 * 2749 * The guidelines on delayed acknowledgement algorithm specified in 2750 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2751 * acknowledgement SHOULD be generated for at least every second packet 2752 * (not every second DATA chunk) received, and SHOULD be generated within 2753 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2754 * situations it may be beneficial for an SCTP transmitter to be more 2755 * conservative than the algorithms detailed in this document allow. 2756 * However, an SCTP transmitter MUST NOT be more aggressive than the 2757 * following algorithms allow. 2758 * 2759 * A SCTP receiver MUST NOT generate more than one SACK for every 2760 * incoming packet, other than to update the offered window as the 2761 * receiving application consumes new data. 2762 * 2763 * Verification Tag: 8.5 Verification Tag [Normal verification] 2764 * 2765 * Inputs 2766 * (endpoint, asoc, chunk) 2767 * 2768 * Outputs 2769 * (asoc, reply_msg, msg_up, timers, counters) 2770 * 2771 * The return value is the disposition of the chunk. 2772 */ 2773 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2774 const struct sctp_association *asoc, 2775 const sctp_subtype_t type, 2776 void *arg, 2777 sctp_cmd_seq_t *commands) 2778 { 2779 struct sctp_chunk *chunk = arg; 2780 int error; 2781 2782 if (!sctp_vtag_verify(chunk, asoc)) { 2783 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2784 SCTP_NULL()); 2785 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2786 } 2787 2788 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2789 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2790 commands); 2791 2792 error = sctp_eat_data(asoc, chunk, commands ); 2793 switch (error) { 2794 case SCTP_IERROR_NO_ERROR: 2795 break; 2796 case SCTP_IERROR_HIGH_TSN: 2797 case SCTP_IERROR_BAD_STREAM: 2798 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2799 goto discard_noforce; 2800 case SCTP_IERROR_DUP_TSN: 2801 case SCTP_IERROR_IGNORE_TSN: 2802 SCTP_INC_STATS(SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2803 goto discard_force; 2804 case SCTP_IERROR_NO_DATA: 2805 goto consume; 2806 default: 2807 BUG(); 2808 } 2809 2810 if (asoc->autoclose) { 2811 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2812 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2813 } 2814 2815 /* If this is the last chunk in a packet, we need to count it 2816 * toward sack generation. Note that we need to SACK every 2817 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2818 * THEM. We elect to NOT generate SACK's if the chunk fails 2819 * the verification tag test. 2820 * 2821 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2822 * 2823 * The SCTP endpoint MUST always acknowledge the reception of 2824 * each valid DATA chunk. 2825 * 2826 * The guidelines on delayed acknowledgement algorithm 2827 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2828 * Specifically, an acknowledgement SHOULD be generated for at 2829 * least every second packet (not every second DATA chunk) 2830 * received, and SHOULD be generated within 200 ms of the 2831 * arrival of any unacknowledged DATA chunk. In some 2832 * situations it may be beneficial for an SCTP transmitter to 2833 * be more conservative than the algorithms detailed in this 2834 * document allow. However, an SCTP transmitter MUST NOT be 2835 * more aggressive than the following algorithms allow. 2836 */ 2837 if (chunk->end_of_packet) 2838 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2839 2840 return SCTP_DISPOSITION_CONSUME; 2841 2842 discard_force: 2843 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2844 * 2845 * When a packet arrives with duplicate DATA chunk(s) and with 2846 * no new DATA chunk(s), the endpoint MUST immediately send a 2847 * SACK with no delay. If a packet arrives with duplicate 2848 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2849 * MAY immediately send a SACK. Normally receipt of duplicate 2850 * DATA chunks will occur when the original SACK chunk was lost 2851 * and the peer's RTO has expired. The duplicate TSN number(s) 2852 * SHOULD be reported in the SACK as duplicate. 2853 */ 2854 /* In our case, we split the MAY SACK advice up whether or not 2855 * the last chunk is a duplicate.' 2856 */ 2857 if (chunk->end_of_packet) 2858 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2859 return SCTP_DISPOSITION_DISCARD; 2860 2861 discard_noforce: 2862 if (chunk->end_of_packet) 2863 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2864 2865 return SCTP_DISPOSITION_DISCARD; 2866 consume: 2867 return SCTP_DISPOSITION_CONSUME; 2868 2869 } 2870 2871 /* 2872 * sctp_sf_eat_data_fast_4_4 2873 * 2874 * Section: 4 (4) 2875 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2876 * DATA chunks without delay. 2877 * 2878 * Verification Tag: 8.5 Verification Tag [Normal verification] 2879 * Inputs 2880 * (endpoint, asoc, chunk) 2881 * 2882 * Outputs 2883 * (asoc, reply_msg, msg_up, timers, counters) 2884 * 2885 * The return value is the disposition of the chunk. 2886 */ 2887 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2888 const struct sctp_association *asoc, 2889 const sctp_subtype_t type, 2890 void *arg, 2891 sctp_cmd_seq_t *commands) 2892 { 2893 struct sctp_chunk *chunk = arg; 2894 int error; 2895 2896 if (!sctp_vtag_verify(chunk, asoc)) { 2897 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2898 SCTP_NULL()); 2899 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2900 } 2901 2902 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2903 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2904 commands); 2905 2906 error = sctp_eat_data(asoc, chunk, commands ); 2907 switch (error) { 2908 case SCTP_IERROR_NO_ERROR: 2909 case SCTP_IERROR_HIGH_TSN: 2910 case SCTP_IERROR_DUP_TSN: 2911 case SCTP_IERROR_IGNORE_TSN: 2912 case SCTP_IERROR_BAD_STREAM: 2913 break; 2914 case SCTP_IERROR_NO_DATA: 2915 goto consume; 2916 default: 2917 BUG(); 2918 } 2919 2920 /* Go a head and force a SACK, since we are shutting down. */ 2921 2922 /* Implementor's Guide. 2923 * 2924 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 2925 * respond to each received packet containing one or more DATA chunk(s) 2926 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 2927 */ 2928 if (chunk->end_of_packet) { 2929 /* We must delay the chunk creation since the cumulative 2930 * TSN has not been updated yet. 2931 */ 2932 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 2933 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2934 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2935 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2936 } 2937 2938 consume: 2939 return SCTP_DISPOSITION_CONSUME; 2940 } 2941 2942 /* 2943 * Section: 6.2 Processing a Received SACK 2944 * D) Any time a SACK arrives, the endpoint performs the following: 2945 * 2946 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 2947 * then drop the SACK. Since Cumulative TSN Ack is monotonically 2948 * increasing, a SACK whose Cumulative TSN Ack is less than the 2949 * Cumulative TSN Ack Point indicates an out-of-order SACK. 2950 * 2951 * ii) Set rwnd equal to the newly received a_rwnd minus the number 2952 * of bytes still outstanding after processing the Cumulative TSN Ack 2953 * and the Gap Ack Blocks. 2954 * 2955 * iii) If the SACK is missing a TSN that was previously 2956 * acknowledged via a Gap Ack Block (e.g., the data receiver 2957 * reneged on the data), then mark the corresponding DATA chunk 2958 * as available for retransmit: Mark it as missing for fast 2959 * retransmit as described in Section 7.2.4 and if no retransmit 2960 * timer is running for the destination address to which the DATA 2961 * chunk was originally transmitted, then T3-rtx is started for 2962 * that destination address. 2963 * 2964 * Verification Tag: 8.5 Verification Tag [Normal verification] 2965 * 2966 * Inputs 2967 * (endpoint, asoc, chunk) 2968 * 2969 * Outputs 2970 * (asoc, reply_msg, msg_up, timers, counters) 2971 * 2972 * The return value is the disposition of the chunk. 2973 */ 2974 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 2975 const struct sctp_association *asoc, 2976 const sctp_subtype_t type, 2977 void *arg, 2978 sctp_cmd_seq_t *commands) 2979 { 2980 struct sctp_chunk *chunk = arg; 2981 sctp_sackhdr_t *sackh; 2982 __u32 ctsn; 2983 2984 if (!sctp_vtag_verify(chunk, asoc)) 2985 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2986 2987 /* Make sure that the SACK chunk has a valid length. */ 2988 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 2989 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2990 commands); 2991 2992 /* Pull the SACK chunk from the data buffer */ 2993 sackh = sctp_sm_pull_sack(chunk); 2994 /* Was this a bogus SACK? */ 2995 if (!sackh) 2996 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2997 chunk->subh.sack_hdr = sackh; 2998 ctsn = ntohl(sackh->cum_tsn_ack); 2999 3000 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3001 * Ack Point, then drop the SACK. Since Cumulative TSN 3002 * Ack is monotonically increasing, a SACK whose 3003 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3004 * Point indicates an out-of-order SACK. 3005 */ 3006 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3007 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3008 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3009 return SCTP_DISPOSITION_DISCARD; 3010 } 3011 3012 /* If Cumulative TSN Ack beyond the max tsn currently 3013 * send, terminating the association and respond to the 3014 * sender with an ABORT. 3015 */ 3016 if (!TSN_lt(ctsn, asoc->next_tsn)) 3017 return sctp_sf_violation_ctsn(ep, asoc, type, arg, commands); 3018 3019 /* Return this SACK for further processing. */ 3020 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 3021 3022 /* Note: We do the rest of the work on the PROCESS_SACK 3023 * sideeffect. 3024 */ 3025 return SCTP_DISPOSITION_CONSUME; 3026 } 3027 3028 /* 3029 * Generate an ABORT in response to a packet. 3030 * 3031 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3032 * 3033 * 8) The receiver should respond to the sender of the OOTB packet with 3034 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3035 * MUST fill in the Verification Tag field of the outbound packet 3036 * with the value found in the Verification Tag field of the OOTB 3037 * packet and set the T-bit in the Chunk Flags to indicate that the 3038 * Verification Tag is reflected. After sending this ABORT, the 3039 * receiver of the OOTB packet shall discard the OOTB packet and take 3040 * no further action. 3041 * 3042 * Verification Tag: 3043 * 3044 * The return value is the disposition of the chunk. 3045 */ 3046 static sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 3047 const struct sctp_association *asoc, 3048 const sctp_subtype_t type, 3049 void *arg, 3050 sctp_cmd_seq_t *commands) 3051 { 3052 struct sctp_packet *packet = NULL; 3053 struct sctp_chunk *chunk = arg; 3054 struct sctp_chunk *abort; 3055 3056 packet = sctp_ootb_pkt_new(asoc, chunk); 3057 3058 if (packet) { 3059 /* Make an ABORT. The T bit will be set if the asoc 3060 * is NULL. 3061 */ 3062 abort = sctp_make_abort(asoc, chunk, 0); 3063 if (!abort) { 3064 sctp_ootb_pkt_free(packet); 3065 return SCTP_DISPOSITION_NOMEM; 3066 } 3067 3068 /* Reflect vtag if T-Bit is set */ 3069 if (sctp_test_T_bit(abort)) 3070 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3071 3072 /* Set the skb to the belonging sock for accounting. */ 3073 abort->skb->sk = ep->base.sk; 3074 3075 sctp_packet_append_chunk(packet, abort); 3076 3077 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3078 SCTP_PACKET(packet)); 3079 3080 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3081 3082 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3083 return SCTP_DISPOSITION_CONSUME; 3084 } 3085 3086 return SCTP_DISPOSITION_NOMEM; 3087 } 3088 3089 /* 3090 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3091 * event as ULP notification for each cause included in the chunk. 3092 * 3093 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3094 * 3095 * The return value is the disposition of the chunk. 3096 */ 3097 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 3098 const struct sctp_association *asoc, 3099 const sctp_subtype_t type, 3100 void *arg, 3101 sctp_cmd_seq_t *commands) 3102 { 3103 struct sctp_chunk *chunk = arg; 3104 struct sctp_ulpevent *ev; 3105 3106 if (!sctp_vtag_verify(chunk, asoc)) 3107 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3108 3109 /* Make sure that the ERROR chunk has a valid length. */ 3110 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3111 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3112 commands); 3113 3114 while (chunk->chunk_end > chunk->skb->data) { 3115 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 3116 GFP_ATOMIC); 3117 if (!ev) 3118 goto nomem; 3119 3120 if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP, 3121 SCTP_ULPEVENT(ev))) { 3122 sctp_ulpevent_free(ev); 3123 goto nomem; 3124 } 3125 3126 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3127 SCTP_CHUNK(chunk)); 3128 } 3129 return SCTP_DISPOSITION_CONSUME; 3130 3131 nomem: 3132 return SCTP_DISPOSITION_NOMEM; 3133 } 3134 3135 /* 3136 * Process an inbound SHUTDOWN ACK. 3137 * 3138 * From Section 9.2: 3139 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3140 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3141 * peer, and remove all record of the association. 3142 * 3143 * The return value is the disposition. 3144 */ 3145 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 3146 const struct sctp_association *asoc, 3147 const sctp_subtype_t type, 3148 void *arg, 3149 sctp_cmd_seq_t *commands) 3150 { 3151 struct sctp_chunk *chunk = arg; 3152 struct sctp_chunk *reply; 3153 struct sctp_ulpevent *ev; 3154 3155 if (!sctp_vtag_verify(chunk, asoc)) 3156 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3157 3158 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3159 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3160 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3161 commands); 3162 /* 10.2 H) SHUTDOWN COMPLETE notification 3163 * 3164 * When SCTP completes the shutdown procedures (section 9.2) this 3165 * notification is passed to the upper layer. 3166 */ 3167 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3168 0, 0, 0, NULL, GFP_ATOMIC); 3169 if (!ev) 3170 goto nomem; 3171 3172 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3173 reply = sctp_make_shutdown_complete(asoc, chunk); 3174 if (!reply) 3175 goto nomem_chunk; 3176 3177 /* Do all the commands now (after allocation), so that we 3178 * have consistent state if memory allocation failes 3179 */ 3180 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3181 3182 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3183 * stop the T2-shutdown timer, 3184 */ 3185 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3186 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3187 3188 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3189 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3190 3191 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3192 SCTP_STATE(SCTP_STATE_CLOSED)); 3193 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3194 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3195 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3196 3197 /* ...and remove all record of the association. */ 3198 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3199 return SCTP_DISPOSITION_DELETE_TCB; 3200 3201 nomem_chunk: 3202 sctp_ulpevent_free(ev); 3203 nomem: 3204 return SCTP_DISPOSITION_NOMEM; 3205 } 3206 3207 /* 3208 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3209 * 3210 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3211 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3212 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3213 * packet must fill in the Verification Tag field of the outbound 3214 * packet with the Verification Tag received in the SHUTDOWN ACK and 3215 * set the T-bit in the Chunk Flags to indicate that the Verification 3216 * Tag is reflected. 3217 * 3218 * 8) The receiver should respond to the sender of the OOTB packet with 3219 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3220 * MUST fill in the Verification Tag field of the outbound packet 3221 * with the value found in the Verification Tag field of the OOTB 3222 * packet and set the T-bit in the Chunk Flags to indicate that the 3223 * Verification Tag is reflected. After sending this ABORT, the 3224 * receiver of the OOTB packet shall discard the OOTB packet and take 3225 * no further action. 3226 */ 3227 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3228 const struct sctp_association *asoc, 3229 const sctp_subtype_t type, 3230 void *arg, 3231 sctp_cmd_seq_t *commands) 3232 { 3233 struct sctp_chunk *chunk = arg; 3234 struct sk_buff *skb = chunk->skb; 3235 sctp_chunkhdr_t *ch; 3236 __u8 *ch_end; 3237 int ootb_shut_ack = 0; 3238 3239 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3240 3241 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3242 do { 3243 /* Report violation if the chunk is less then minimal */ 3244 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3245 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3246 commands); 3247 3248 /* Now that we know we at least have a chunk header, 3249 * do things that are type appropriate. 3250 */ 3251 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3252 ootb_shut_ack = 1; 3253 3254 /* RFC 2960, Section 3.3.7 3255 * Moreover, under any circumstances, an endpoint that 3256 * receives an ABORT MUST NOT respond to that ABORT by 3257 * sending an ABORT of its own. 3258 */ 3259 if (SCTP_CID_ABORT == ch->type) 3260 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3261 3262 /* Report violation if chunk len overflows */ 3263 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3264 if (ch_end > skb_tail_pointer(skb)) 3265 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3266 commands); 3267 3268 ch = (sctp_chunkhdr_t *) ch_end; 3269 } while (ch_end < skb_tail_pointer(skb)); 3270 3271 if (ootb_shut_ack) 3272 return sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3273 else 3274 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3275 } 3276 3277 /* 3278 * Handle an "Out of the blue" SHUTDOWN ACK. 3279 * 3280 * Section: 8.4 5, sctpimpguide 2.41. 3281 * 3282 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3283 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3284 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3285 * packet must fill in the Verification Tag field of the outbound 3286 * packet with the Verification Tag received in the SHUTDOWN ACK and 3287 * set the T-bit in the Chunk Flags to indicate that the Verification 3288 * Tag is reflected. 3289 * 3290 * Inputs 3291 * (endpoint, asoc, type, arg, commands) 3292 * 3293 * Outputs 3294 * (sctp_disposition_t) 3295 * 3296 * The return value is the disposition of the chunk. 3297 */ 3298 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3299 const struct sctp_association *asoc, 3300 const sctp_subtype_t type, 3301 void *arg, 3302 sctp_cmd_seq_t *commands) 3303 { 3304 struct sctp_packet *packet = NULL; 3305 struct sctp_chunk *chunk = arg; 3306 struct sctp_chunk *shut; 3307 3308 packet = sctp_ootb_pkt_new(asoc, chunk); 3309 3310 if (packet) { 3311 /* Make an SHUTDOWN_COMPLETE. 3312 * The T bit will be set if the asoc is NULL. 3313 */ 3314 shut = sctp_make_shutdown_complete(asoc, chunk); 3315 if (!shut) { 3316 sctp_ootb_pkt_free(packet); 3317 return SCTP_DISPOSITION_NOMEM; 3318 } 3319 3320 /* Reflect vtag if T-Bit is set */ 3321 if (sctp_test_T_bit(shut)) 3322 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3323 3324 /* Set the skb to the belonging sock for accounting. */ 3325 shut->skb->sk = ep->base.sk; 3326 3327 sctp_packet_append_chunk(packet, shut); 3328 3329 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3330 SCTP_PACKET(packet)); 3331 3332 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3333 3334 /* If the chunk length is invalid, we don't want to process 3335 * the reset of the packet. 3336 */ 3337 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3338 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3339 3340 /* We need to discard the rest of the packet to prevent 3341 * potential bomming attacks from additional bundled chunks. 3342 * This is documented in SCTP Threats ID. 3343 */ 3344 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3345 } 3346 3347 return SCTP_DISPOSITION_NOMEM; 3348 } 3349 3350 /* 3351 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3352 * 3353 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3354 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3355 * procedures in section 8.4 SHOULD be followed, in other words it 3356 * should be treated as an Out Of The Blue packet. 3357 * [This means that we do NOT check the Verification Tag on these 3358 * chunks. --piggy ] 3359 * 3360 */ 3361 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3362 const struct sctp_association *asoc, 3363 const sctp_subtype_t type, 3364 void *arg, 3365 sctp_cmd_seq_t *commands) 3366 { 3367 struct sctp_chunk *chunk = arg; 3368 3369 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3370 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3371 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3372 commands); 3373 3374 /* Although we do have an association in this case, it corresponds 3375 * to a restarted association. So the packet is treated as an OOTB 3376 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3377 * called with a NULL association. 3378 */ 3379 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3380 } 3381 3382 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3383 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3384 const struct sctp_association *asoc, 3385 const sctp_subtype_t type, void *arg, 3386 sctp_cmd_seq_t *commands) 3387 { 3388 struct sctp_chunk *chunk = arg; 3389 struct sctp_chunk *asconf_ack = NULL; 3390 struct sctp_paramhdr *err_param = NULL; 3391 sctp_addiphdr_t *hdr; 3392 union sctp_addr_param *addr_param; 3393 __u32 serial; 3394 int length; 3395 3396 if (!sctp_vtag_verify(chunk, asoc)) { 3397 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3398 SCTP_NULL()); 3399 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3400 } 3401 3402 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3403 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3404 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3405 commands); 3406 3407 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3408 serial = ntohl(hdr->serial); 3409 3410 addr_param = (union sctp_addr_param *)hdr->params; 3411 length = ntohs(addr_param->p.length); 3412 if (length < sizeof(sctp_paramhdr_t)) 3413 return sctp_sf_violation_paramlen(ep, asoc, type, 3414 (void *)addr_param, commands); 3415 3416 /* Verify the ASCONF chunk before processing it. */ 3417 if (!sctp_verify_asconf(asoc, 3418 (sctp_paramhdr_t *)((void *)addr_param + length), 3419 (void *)chunk->chunk_end, 3420 &err_param)) 3421 return sctp_sf_violation_paramlen(ep, asoc, type, 3422 (void *)&err_param, commands); 3423 3424 /* ADDIP 4.2 C1) Compare the value of the serial number to the value 3425 * the endpoint stored in a new association variable 3426 * 'Peer-Serial-Number'. 3427 */ 3428 if (serial == asoc->peer.addip_serial + 1) { 3429 /* ADDIP 4.2 C2) If the value found in the serial number is 3430 * equal to the ('Peer-Serial-Number' + 1), the endpoint MUST 3431 * do V1-V5. 3432 */ 3433 asconf_ack = sctp_process_asconf((struct sctp_association *) 3434 asoc, chunk); 3435 if (!asconf_ack) 3436 return SCTP_DISPOSITION_NOMEM; 3437 } else if (serial == asoc->peer.addip_serial) { 3438 /* ADDIP 4.2 C3) If the value found in the serial number is 3439 * equal to the value stored in the 'Peer-Serial-Number' 3440 * IMPLEMENTATION NOTE: As an optimization a receiver may wish 3441 * to save the last ASCONF-ACK for some predetermined period of 3442 * time and instead of re-processing the ASCONF (with the same 3443 * serial number) it may just re-transmit the ASCONF-ACK. 3444 */ 3445 if (asoc->addip_last_asconf_ack) 3446 asconf_ack = asoc->addip_last_asconf_ack; 3447 else 3448 return SCTP_DISPOSITION_DISCARD; 3449 } else { 3450 /* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since 3451 * it must be either a stale packet or from an attacker. 3452 */ 3453 return SCTP_DISPOSITION_DISCARD; 3454 } 3455 3456 /* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent 3457 * back to the source address contained in the IP header of the ASCONF 3458 * being responded to. 3459 */ 3460 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3461 3462 return SCTP_DISPOSITION_CONSUME; 3463 } 3464 3465 /* 3466 * ADDIP Section 4.3 General rules for address manipulation 3467 * When building TLV parameters for the ASCONF Chunk that will add or 3468 * delete IP addresses the D0 to D13 rules should be applied: 3469 */ 3470 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3471 const struct sctp_association *asoc, 3472 const sctp_subtype_t type, void *arg, 3473 sctp_cmd_seq_t *commands) 3474 { 3475 struct sctp_chunk *asconf_ack = arg; 3476 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3477 struct sctp_chunk *abort; 3478 struct sctp_paramhdr *err_param = NULL; 3479 sctp_addiphdr_t *addip_hdr; 3480 __u32 sent_serial, rcvd_serial; 3481 3482 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3483 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3484 SCTP_NULL()); 3485 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3486 } 3487 3488 /* Make sure that the ADDIP chunk has a valid length. */ 3489 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3490 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3491 commands); 3492 3493 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3494 rcvd_serial = ntohl(addip_hdr->serial); 3495 3496 /* Verify the ASCONF-ACK chunk before processing it. */ 3497 if (!sctp_verify_asconf(asoc, 3498 (sctp_paramhdr_t *)addip_hdr->params, 3499 (void *)asconf_ack->chunk_end, 3500 &err_param)) 3501 return sctp_sf_violation_paramlen(ep, asoc, type, 3502 (void *)&err_param, commands); 3503 3504 if (last_asconf) { 3505 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3506 sent_serial = ntohl(addip_hdr->serial); 3507 } else { 3508 sent_serial = asoc->addip_serial - 1; 3509 } 3510 3511 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3512 * equal to the next serial number to be used but no ASCONF chunk is 3513 * outstanding the endpoint MUST ABORT the association. Note that a 3514 * sequence number is greater than if it is no more than 2^^31-1 3515 * larger than the current sequence number (using serial arithmetic). 3516 */ 3517 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3518 !(asoc->addip_last_asconf)) { 3519 abort = sctp_make_abort(asoc, asconf_ack, 3520 sizeof(sctp_errhdr_t)); 3521 if (abort) { 3522 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3523 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3524 SCTP_CHUNK(abort)); 3525 } 3526 /* We are going to ABORT, so we might as well stop 3527 * processing the rest of the chunks in the packet. 3528 */ 3529 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3530 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3531 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3532 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3533 SCTP_ERROR(ECONNABORTED)); 3534 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3535 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3536 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3537 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3538 return SCTP_DISPOSITION_ABORT; 3539 } 3540 3541 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3542 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3543 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3544 3545 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3546 asconf_ack)) 3547 return SCTP_DISPOSITION_CONSUME; 3548 3549 abort = sctp_make_abort(asoc, asconf_ack, 3550 sizeof(sctp_errhdr_t)); 3551 if (abort) { 3552 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3553 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3554 SCTP_CHUNK(abort)); 3555 } 3556 /* We are going to ABORT, so we might as well stop 3557 * processing the rest of the chunks in the packet. 3558 */ 3559 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3560 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3561 SCTP_ERROR(ECONNABORTED)); 3562 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3563 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3564 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3565 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3566 return SCTP_DISPOSITION_ABORT; 3567 } 3568 3569 return SCTP_DISPOSITION_DISCARD; 3570 } 3571 3572 /* 3573 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3574 * 3575 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3576 * its cumulative TSN point to the value carried in the FORWARD TSN 3577 * chunk, and then MUST further advance its cumulative TSN point locally 3578 * if possible. 3579 * After the above processing, the data receiver MUST stop reporting any 3580 * missing TSNs earlier than or equal to the new cumulative TSN point. 3581 * 3582 * Verification Tag: 8.5 Verification Tag [Normal verification] 3583 * 3584 * The return value is the disposition of the chunk. 3585 */ 3586 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3587 const struct sctp_association *asoc, 3588 const sctp_subtype_t type, 3589 void *arg, 3590 sctp_cmd_seq_t *commands) 3591 { 3592 struct sctp_chunk *chunk = arg; 3593 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3594 __u16 len; 3595 __u32 tsn; 3596 3597 if (!sctp_vtag_verify(chunk, asoc)) { 3598 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3599 SCTP_NULL()); 3600 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3601 } 3602 3603 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3604 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3605 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3606 commands); 3607 3608 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3609 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3610 len = ntohs(chunk->chunk_hdr->length); 3611 len -= sizeof(struct sctp_chunkhdr); 3612 skb_pull(chunk->skb, len); 3613 3614 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3615 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3616 3617 /* The TSN is too high--silently discard the chunk and count on it 3618 * getting retransmitted later. 3619 */ 3620 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3621 goto discard_noforce; 3622 3623 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3624 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3625 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3626 SCTP_CHUNK(chunk)); 3627 3628 /* Count this as receiving DATA. */ 3629 if (asoc->autoclose) { 3630 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3631 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3632 } 3633 3634 /* FIXME: For now send a SACK, but DATA processing may 3635 * send another. 3636 */ 3637 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3638 3639 return SCTP_DISPOSITION_CONSUME; 3640 3641 discard_noforce: 3642 return SCTP_DISPOSITION_DISCARD; 3643 } 3644 3645 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3646 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 struct sctp_chunk *chunk = arg; 3653 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3654 __u16 len; 3655 __u32 tsn; 3656 3657 if (!sctp_vtag_verify(chunk, asoc)) { 3658 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3659 SCTP_NULL()); 3660 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3661 } 3662 3663 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3664 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3665 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3666 commands); 3667 3668 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3669 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3670 len = ntohs(chunk->chunk_hdr->length); 3671 len -= sizeof(struct sctp_chunkhdr); 3672 skb_pull(chunk->skb, len); 3673 3674 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3675 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3676 3677 /* The TSN is too high--silently discard the chunk and count on it 3678 * getting retransmitted later. 3679 */ 3680 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3681 goto gen_shutdown; 3682 3683 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3684 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3685 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3686 SCTP_CHUNK(chunk)); 3687 3688 /* Go a head and force a SACK, since we are shutting down. */ 3689 gen_shutdown: 3690 /* Implementor's Guide. 3691 * 3692 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3693 * respond to each received packet containing one or more DATA chunk(s) 3694 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3695 */ 3696 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3697 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3698 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3699 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3700 3701 return SCTP_DISPOSITION_CONSUME; 3702 } 3703 3704 /* 3705 * SCTP-AUTH Section 6.3 Receving authenticated chukns 3706 * 3707 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3708 * Identifier field. If this algorithm was not specified by the 3709 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3710 * during association setup, the AUTH chunk and all chunks after it MUST 3711 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3712 * defined in Section 4.1. 3713 * 3714 * If an endpoint with no shared key receives a Shared Key Identifier 3715 * other than 0, it MUST silently discard all authenticated chunks. If 3716 * the endpoint has at least one endpoint pair shared key for the peer, 3717 * it MUST use the key specified by the Shared Key Identifier if a 3718 * key has been configured for that Shared Key Identifier. If no 3719 * endpoint pair shared key has been configured for that Shared Key 3720 * Identifier, all authenticated chunks MUST be silently discarded. 3721 * 3722 * Verification Tag: 8.5 Verification Tag [Normal verification] 3723 * 3724 * The return value is the disposition of the chunk. 3725 */ 3726 static sctp_ierror_t sctp_sf_authenticate(const struct sctp_endpoint *ep, 3727 const struct sctp_association *asoc, 3728 const sctp_subtype_t type, 3729 struct sctp_chunk *chunk) 3730 { 3731 struct sctp_authhdr *auth_hdr; 3732 struct sctp_hmac *hmac; 3733 unsigned int sig_len; 3734 __u16 key_id; 3735 __u8 *save_digest; 3736 __u8 *digest; 3737 3738 /* Pull in the auth header, so we can do some more verification */ 3739 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3740 chunk->subh.auth_hdr = auth_hdr; 3741 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3742 3743 /* Make sure that we suport the HMAC algorithm from the auth 3744 * chunk. 3745 */ 3746 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 3747 return SCTP_IERROR_AUTH_BAD_HMAC; 3748 3749 /* Make sure that the provided shared key identifier has been 3750 * configured 3751 */ 3752 key_id = ntohs(auth_hdr->shkey_id); 3753 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 3754 return SCTP_IERROR_AUTH_BAD_KEYID; 3755 3756 3757 /* Make sure that the length of the signature matches what 3758 * we expect. 3759 */ 3760 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 3761 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 3762 if (sig_len != hmac->hmac_len) 3763 return SCTP_IERROR_PROTO_VIOLATION; 3764 3765 /* Now that we've done validation checks, we can compute and 3766 * verify the hmac. The steps involved are: 3767 * 1. Save the digest from the chunk. 3768 * 2. Zero out the digest in the chunk. 3769 * 3. Compute the new digest 3770 * 4. Compare saved and new digests. 3771 */ 3772 digest = auth_hdr->hmac; 3773 skb_pull(chunk->skb, sig_len); 3774 3775 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 3776 if (!save_digest) 3777 goto nomem; 3778 3779 memset(digest, 0, sig_len); 3780 3781 sctp_auth_calculate_hmac(asoc, chunk->skb, 3782 (struct sctp_auth_chunk *)chunk->chunk_hdr, 3783 GFP_ATOMIC); 3784 3785 /* Discard the packet if the digests do not match */ 3786 if (memcmp(save_digest, digest, sig_len)) { 3787 kfree(save_digest); 3788 return SCTP_IERROR_BAD_SIG; 3789 } 3790 3791 kfree(save_digest); 3792 chunk->auth = 1; 3793 3794 return SCTP_IERROR_NO_ERROR; 3795 nomem: 3796 return SCTP_IERROR_NOMEM; 3797 } 3798 3799 sctp_disposition_t sctp_sf_eat_auth(const struct sctp_endpoint *ep, 3800 const struct sctp_association *asoc, 3801 const sctp_subtype_t type, 3802 void *arg, 3803 sctp_cmd_seq_t *commands) 3804 { 3805 struct sctp_authhdr *auth_hdr; 3806 struct sctp_chunk *chunk = arg; 3807 struct sctp_chunk *err_chunk; 3808 sctp_ierror_t error; 3809 3810 if (!sctp_vtag_verify(chunk, asoc)) { 3811 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3812 SCTP_NULL()); 3813 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3814 } 3815 3816 /* Make sure that the AUTH chunk has valid length. */ 3817 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 3818 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3819 commands); 3820 3821 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3822 error = sctp_sf_authenticate(ep, asoc, type, chunk); 3823 switch (error) { 3824 case SCTP_IERROR_AUTH_BAD_HMAC: 3825 /* Generate the ERROR chunk and discard the rest 3826 * of the packet 3827 */ 3828 err_chunk = sctp_make_op_error(asoc, chunk, 3829 SCTP_ERROR_UNSUP_HMAC, 3830 &auth_hdr->hmac_id, 3831 sizeof(__u16)); 3832 if (err_chunk) { 3833 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3834 SCTP_CHUNK(err_chunk)); 3835 } 3836 /* Fall Through */ 3837 case SCTP_IERROR_AUTH_BAD_KEYID: 3838 case SCTP_IERROR_BAD_SIG: 3839 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3840 break; 3841 case SCTP_IERROR_PROTO_VIOLATION: 3842 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3843 commands); 3844 break; 3845 case SCTP_IERROR_NOMEM: 3846 return SCTP_DISPOSITION_NOMEM; 3847 default: 3848 break; 3849 } 3850 3851 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 3852 struct sctp_ulpevent *ev; 3853 3854 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 3855 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 3856 3857 if (!ev) 3858 return -ENOMEM; 3859 3860 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3861 SCTP_ULPEVENT(ev)); 3862 } 3863 3864 return SCTP_DISPOSITION_CONSUME; 3865 } 3866 3867 /* 3868 * Process an unknown chunk. 3869 * 3870 * Section: 3.2. Also, 2.1 in the implementor's guide. 3871 * 3872 * Chunk Types are encoded such that the highest-order two bits specify 3873 * the action that must be taken if the processing endpoint does not 3874 * recognize the Chunk Type. 3875 * 3876 * 00 - Stop processing this SCTP packet and discard it, do not process 3877 * any further chunks within it. 3878 * 3879 * 01 - Stop processing this SCTP packet and discard it, do not process 3880 * any further chunks within it, and report the unrecognized 3881 * chunk in an 'Unrecognized Chunk Type'. 3882 * 3883 * 10 - Skip this chunk and continue processing. 3884 * 3885 * 11 - Skip this chunk and continue processing, but report in an ERROR 3886 * Chunk using the 'Unrecognized Chunk Type' cause of error. 3887 * 3888 * The return value is the disposition of the chunk. 3889 */ 3890 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 3891 const struct sctp_association *asoc, 3892 const sctp_subtype_t type, 3893 void *arg, 3894 sctp_cmd_seq_t *commands) 3895 { 3896 struct sctp_chunk *unk_chunk = arg; 3897 struct sctp_chunk *err_chunk; 3898 sctp_chunkhdr_t *hdr; 3899 3900 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 3901 3902 if (!sctp_vtag_verify(unk_chunk, asoc)) 3903 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3904 3905 /* Make sure that the chunk has a valid length. 3906 * Since we don't know the chunk type, we use a general 3907 * chunkhdr structure to make a comparison. 3908 */ 3909 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 3910 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3911 commands); 3912 3913 switch (type.chunk & SCTP_CID_ACTION_MASK) { 3914 case SCTP_CID_ACTION_DISCARD: 3915 /* Discard the packet. */ 3916 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3917 break; 3918 case SCTP_CID_ACTION_DISCARD_ERR: 3919 /* Discard the packet. */ 3920 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3921 3922 /* Generate an ERROR chunk as response. */ 3923 hdr = unk_chunk->chunk_hdr; 3924 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3925 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3926 WORD_ROUND(ntohs(hdr->length))); 3927 if (err_chunk) { 3928 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3929 SCTP_CHUNK(err_chunk)); 3930 } 3931 return SCTP_DISPOSITION_CONSUME; 3932 break; 3933 case SCTP_CID_ACTION_SKIP: 3934 /* Skip the chunk. */ 3935 return SCTP_DISPOSITION_DISCARD; 3936 break; 3937 case SCTP_CID_ACTION_SKIP_ERR: 3938 /* Generate an ERROR chunk as response. */ 3939 hdr = unk_chunk->chunk_hdr; 3940 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3941 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3942 WORD_ROUND(ntohs(hdr->length))); 3943 if (err_chunk) { 3944 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3945 SCTP_CHUNK(err_chunk)); 3946 } 3947 /* Skip the chunk. */ 3948 return SCTP_DISPOSITION_CONSUME; 3949 break; 3950 default: 3951 break; 3952 } 3953 3954 return SCTP_DISPOSITION_DISCARD; 3955 } 3956 3957 /* 3958 * Discard the chunk. 3959 * 3960 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 3961 * [Too numerous to mention...] 3962 * Verification Tag: No verification needed. 3963 * Inputs 3964 * (endpoint, asoc, chunk) 3965 * 3966 * Outputs 3967 * (asoc, reply_msg, msg_up, timers, counters) 3968 * 3969 * The return value is the disposition of the chunk. 3970 */ 3971 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 3972 const struct sctp_association *asoc, 3973 const sctp_subtype_t type, 3974 void *arg, 3975 sctp_cmd_seq_t *commands) 3976 { 3977 struct sctp_chunk *chunk = arg; 3978 3979 /* Make sure that the chunk has a valid length. 3980 * Since we don't know the chunk type, we use a general 3981 * chunkhdr structure to make a comparison. 3982 */ 3983 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3984 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3985 commands); 3986 3987 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 3988 return SCTP_DISPOSITION_DISCARD; 3989 } 3990 3991 /* 3992 * Discard the whole packet. 3993 * 3994 * Section: 8.4 2) 3995 * 3996 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 3997 * silently discard the OOTB packet and take no further action. 3998 * 3999 * Verification Tag: No verification necessary 4000 * 4001 * Inputs 4002 * (endpoint, asoc, chunk) 4003 * 4004 * Outputs 4005 * (asoc, reply_msg, msg_up, timers, counters) 4006 * 4007 * The return value is the disposition of the chunk. 4008 */ 4009 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 4010 const struct sctp_association *asoc, 4011 const sctp_subtype_t type, 4012 void *arg, 4013 sctp_cmd_seq_t *commands) 4014 { 4015 SCTP_INC_STATS(SCTP_MIB_IN_PKT_DISCARDS); 4016 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4017 4018 return SCTP_DISPOSITION_CONSUME; 4019 } 4020 4021 4022 /* 4023 * The other end is violating protocol. 4024 * 4025 * Section: Not specified 4026 * Verification Tag: Not specified 4027 * Inputs 4028 * (endpoint, asoc, chunk) 4029 * 4030 * Outputs 4031 * (asoc, reply_msg, msg_up, timers, counters) 4032 * 4033 * We simply tag the chunk as a violation. The state machine will log 4034 * the violation and continue. 4035 */ 4036 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 4037 const struct sctp_association *asoc, 4038 const sctp_subtype_t type, 4039 void *arg, 4040 sctp_cmd_seq_t *commands) 4041 { 4042 struct sctp_chunk *chunk = arg; 4043 4044 /* Make sure that the chunk has a valid length. */ 4045 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4046 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4047 commands); 4048 4049 return SCTP_DISPOSITION_VIOLATION; 4050 } 4051 4052 /* 4053 * Common function to handle a protocol violation. 4054 */ 4055 static sctp_disposition_t sctp_sf_abort_violation( 4056 const struct sctp_endpoint *ep, 4057 const struct sctp_association *asoc, 4058 void *arg, 4059 sctp_cmd_seq_t *commands, 4060 const __u8 *payload, 4061 const size_t paylen) 4062 { 4063 struct sctp_packet *packet = NULL; 4064 struct sctp_chunk *chunk = arg; 4065 struct sctp_chunk *abort = NULL; 4066 4067 /* Make the abort chunk. */ 4068 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4069 if (!abort) 4070 goto nomem; 4071 4072 /* SCTP-AUTH, Section 6.3: 4073 * It should be noted that if the receiver wants to tear 4074 * down an association in an authenticated way only, the 4075 * handling of malformed packets should not result in 4076 * tearing down the association. 4077 * 4078 * This means that if we only want to abort associations 4079 * in an authenticated way (i.e AUTH+ABORT), then we 4080 * can't destory this association just becuase the packet 4081 * was malformed. 4082 */ 4083 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4084 goto discard; 4085 4086 if (asoc) { 4087 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4088 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4089 4090 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4091 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4092 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4093 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4094 SCTP_ERROR(ECONNREFUSED)); 4095 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4096 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4097 } else { 4098 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4099 SCTP_ERROR(ECONNABORTED)); 4100 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4101 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4102 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4103 } 4104 } else { 4105 packet = sctp_ootb_pkt_new(asoc, chunk); 4106 4107 if (!packet) 4108 goto nomem_pkt; 4109 4110 if (sctp_test_T_bit(abort)) 4111 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4112 4113 abort->skb->sk = ep->base.sk; 4114 4115 sctp_packet_append_chunk(packet, abort); 4116 4117 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4118 SCTP_PACKET(packet)); 4119 4120 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 4121 } 4122 4123 discard: 4124 sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4125 4126 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4127 4128 return SCTP_DISPOSITION_ABORT; 4129 4130 nomem_pkt: 4131 sctp_chunk_free(abort); 4132 nomem: 4133 return SCTP_DISPOSITION_NOMEM; 4134 } 4135 4136 /* 4137 * Handle a protocol violation when the chunk length is invalid. 4138 * "Invalid" length is identified as smaller then the minimal length a 4139 * given chunk can be. For example, a SACK chunk has invalid length 4140 * if it's length is set to be smaller then the size of sctp_sack_chunk_t. 4141 * 4142 * We inform the other end by sending an ABORT with a Protocol Violation 4143 * error code. 4144 * 4145 * Section: Not specified 4146 * Verification Tag: Nothing to do 4147 * Inputs 4148 * (endpoint, asoc, chunk) 4149 * 4150 * Outputs 4151 * (reply_msg, msg_up, counters) 4152 * 4153 * Generate an ABORT chunk and terminate the association. 4154 */ 4155 static sctp_disposition_t sctp_sf_violation_chunklen( 4156 const struct sctp_endpoint *ep, 4157 const struct sctp_association *asoc, 4158 const sctp_subtype_t type, 4159 void *arg, 4160 sctp_cmd_seq_t *commands) 4161 { 4162 char err_str[]="The following chunk had invalid length:"; 4163 4164 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4165 sizeof(err_str)); 4166 } 4167 4168 /* 4169 * Handle a protocol violation when the parameter length is invalid. 4170 * "Invalid" length is identified as smaller then the minimal length a 4171 * given parameter can be. 4172 */ 4173 static sctp_disposition_t sctp_sf_violation_paramlen( 4174 const struct sctp_endpoint *ep, 4175 const struct sctp_association *asoc, 4176 const sctp_subtype_t type, 4177 void *arg, 4178 sctp_cmd_seq_t *commands) { 4179 char err_str[] = "The following parameter had invalid length:"; 4180 4181 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4182 sizeof(err_str)); 4183 } 4184 4185 /* Handle a protocol violation when the peer trying to advance the 4186 * cumulative tsn ack to a point beyond the max tsn currently sent. 4187 * 4188 * We inform the other end by sending an ABORT with a Protocol Violation 4189 * error code. 4190 */ 4191 static sctp_disposition_t sctp_sf_violation_ctsn( 4192 const struct sctp_endpoint *ep, 4193 const struct sctp_association *asoc, 4194 const sctp_subtype_t type, 4195 void *arg, 4196 sctp_cmd_seq_t *commands) 4197 { 4198 char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4199 4200 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4201 sizeof(err_str)); 4202 } 4203 4204 /* Handle protocol violation of an invalid chunk bundling. For example, 4205 * when we have an association and we recieve bundled INIT-ACK, or 4206 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4207 * statement from the specs. Additinally, there might be an attacker 4208 * on the path and we may not want to continue this communication. 4209 */ 4210 static sctp_disposition_t sctp_sf_violation_chunk( 4211 const struct sctp_endpoint *ep, 4212 const struct sctp_association *asoc, 4213 const sctp_subtype_t type, 4214 void *arg, 4215 sctp_cmd_seq_t *commands) 4216 { 4217 char err_str[]="The following chunk violates protocol:"; 4218 4219 if (!asoc) 4220 return sctp_sf_violation(ep, asoc, type, arg, commands); 4221 4222 return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str, 4223 sizeof(err_str)); 4224 } 4225 /*************************************************************************** 4226 * These are the state functions for handling primitive (Section 10) events. 4227 ***************************************************************************/ 4228 /* 4229 * sctp_sf_do_prm_asoc 4230 * 4231 * Section: 10.1 ULP-to-SCTP 4232 * B) Associate 4233 * 4234 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4235 * outbound stream count) 4236 * -> association id [,destination transport addr list] [,outbound stream 4237 * count] 4238 * 4239 * This primitive allows the upper layer to initiate an association to a 4240 * specific peer endpoint. 4241 * 4242 * The peer endpoint shall be specified by one of the transport addresses 4243 * which defines the endpoint (see Section 1.4). If the local SCTP 4244 * instance has not been initialized, the ASSOCIATE is considered an 4245 * error. 4246 * [This is not relevant for the kernel implementation since we do all 4247 * initialization at boot time. It we hadn't initialized we wouldn't 4248 * get anywhere near this code.] 4249 * 4250 * An association id, which is a local handle to the SCTP association, 4251 * will be returned on successful establishment of the association. If 4252 * SCTP is not able to open an SCTP association with the peer endpoint, 4253 * an error is returned. 4254 * [In the kernel implementation, the struct sctp_association needs to 4255 * be created BEFORE causing this primitive to run.] 4256 * 4257 * Other association parameters may be returned, including the 4258 * complete destination transport addresses of the peer as well as the 4259 * outbound stream count of the local endpoint. One of the transport 4260 * address from the returned destination addresses will be selected by 4261 * the local endpoint as default primary path for sending SCTP packets 4262 * to this peer. The returned "destination transport addr list" can 4263 * be used by the ULP to change the default primary path or to force 4264 * sending a packet to a specific transport address. [All of this 4265 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4266 * function.] 4267 * 4268 * Mandatory attributes: 4269 * 4270 * o local SCTP instance name - obtained from the INITIALIZE operation. 4271 * [This is the argument asoc.] 4272 * o destination transport addr - specified as one of the transport 4273 * addresses of the peer endpoint with which the association is to be 4274 * established. 4275 * [This is asoc->peer.active_path.] 4276 * o outbound stream count - the number of outbound streams the ULP 4277 * would like to open towards this peer endpoint. 4278 * [BUG: This is not currently implemented.] 4279 * Optional attributes: 4280 * 4281 * None. 4282 * 4283 * The return value is a disposition. 4284 */ 4285 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 4286 const struct sctp_association *asoc, 4287 const sctp_subtype_t type, 4288 void *arg, 4289 sctp_cmd_seq_t *commands) 4290 { 4291 struct sctp_chunk *repl; 4292 4293 /* The comment below says that we enter COOKIE-WAIT AFTER 4294 * sending the INIT, but that doesn't actually work in our 4295 * implementation... 4296 */ 4297 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4298 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4299 4300 /* RFC 2960 5.1 Normal Establishment of an Association 4301 * 4302 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4303 * must provide its Verification Tag (Tag_A) in the Initiate 4304 * Tag field. Tag_A SHOULD be a random number in the range of 4305 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4306 */ 4307 4308 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4309 if (!repl) 4310 goto nomem; 4311 4312 /* Cast away the const modifier, as we want to just 4313 * rerun it through as a sideffect. 4314 */ 4315 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, 4316 SCTP_ASOC((struct sctp_association *) asoc)); 4317 4318 /* Choose transport for INIT. */ 4319 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4320 SCTP_CHUNK(repl)); 4321 4322 /* After sending the INIT, "A" starts the T1-init timer and 4323 * enters the COOKIE-WAIT state. 4324 */ 4325 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4326 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4327 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4328 return SCTP_DISPOSITION_CONSUME; 4329 4330 nomem: 4331 return SCTP_DISPOSITION_NOMEM; 4332 } 4333 4334 /* 4335 * Process the SEND primitive. 4336 * 4337 * Section: 10.1 ULP-to-SCTP 4338 * E) Send 4339 * 4340 * Format: SEND(association id, buffer address, byte count [,context] 4341 * [,stream id] [,life time] [,destination transport address] 4342 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4343 * -> result 4344 * 4345 * This is the main method to send user data via SCTP. 4346 * 4347 * Mandatory attributes: 4348 * 4349 * o association id - local handle to the SCTP association 4350 * 4351 * o buffer address - the location where the user message to be 4352 * transmitted is stored; 4353 * 4354 * o byte count - The size of the user data in number of bytes; 4355 * 4356 * Optional attributes: 4357 * 4358 * o context - an optional 32 bit integer that will be carried in the 4359 * sending failure notification to the ULP if the transportation of 4360 * this User Message fails. 4361 * 4362 * o stream id - to indicate which stream to send the data on. If not 4363 * specified, stream 0 will be used. 4364 * 4365 * o life time - specifies the life time of the user data. The user data 4366 * will not be sent by SCTP after the life time expires. This 4367 * parameter can be used to avoid efforts to transmit stale 4368 * user messages. SCTP notifies the ULP if the data cannot be 4369 * initiated to transport (i.e. sent to the destination via SCTP's 4370 * send primitive) within the life time variable. However, the 4371 * user data will be transmitted if SCTP has attempted to transmit a 4372 * chunk before the life time expired. 4373 * 4374 * o destination transport address - specified as one of the destination 4375 * transport addresses of the peer endpoint to which this packet 4376 * should be sent. Whenever possible, SCTP should use this destination 4377 * transport address for sending the packets, instead of the current 4378 * primary path. 4379 * 4380 * o unorder flag - this flag, if present, indicates that the user 4381 * would like the data delivered in an unordered fashion to the peer 4382 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4383 * message). 4384 * 4385 * o no-bundle flag - instructs SCTP not to bundle this user data with 4386 * other outbound DATA chunks. SCTP MAY still bundle even when 4387 * this flag is present, when faced with network congestion. 4388 * 4389 * o payload protocol-id - A 32 bit unsigned integer that is to be 4390 * passed to the peer indicating the type of payload protocol data 4391 * being transmitted. This value is passed as opaque data by SCTP. 4392 * 4393 * The return value is the disposition. 4394 */ 4395 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 4396 const struct sctp_association *asoc, 4397 const sctp_subtype_t type, 4398 void *arg, 4399 sctp_cmd_seq_t *commands) 4400 { 4401 struct sctp_chunk *chunk = arg; 4402 4403 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4404 return SCTP_DISPOSITION_CONSUME; 4405 } 4406 4407 /* 4408 * Process the SHUTDOWN primitive. 4409 * 4410 * Section: 10.1: 4411 * C) Shutdown 4412 * 4413 * Format: SHUTDOWN(association id) 4414 * -> result 4415 * 4416 * Gracefully closes an association. Any locally queued user data 4417 * will be delivered to the peer. The association will be terminated only 4418 * after the peer acknowledges all the SCTP packets sent. A success code 4419 * will be returned on successful termination of the association. If 4420 * attempting to terminate the association results in a failure, an error 4421 * code shall be returned. 4422 * 4423 * Mandatory attributes: 4424 * 4425 * o association id - local handle to the SCTP association 4426 * 4427 * Optional attributes: 4428 * 4429 * None. 4430 * 4431 * The return value is the disposition. 4432 */ 4433 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4434 const struct sctp_endpoint *ep, 4435 const struct sctp_association *asoc, 4436 const sctp_subtype_t type, 4437 void *arg, 4438 sctp_cmd_seq_t *commands) 4439 { 4440 int disposition; 4441 4442 /* From 9.2 Shutdown of an Association 4443 * Upon receipt of the SHUTDOWN primitive from its upper 4444 * layer, the endpoint enters SHUTDOWN-PENDING state and 4445 * remains there until all outstanding data has been 4446 * acknowledged by its peer. The endpoint accepts no new data 4447 * from its upper layer, but retransmits data to the far end 4448 * if necessary to fill gaps. 4449 */ 4450 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4451 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4452 4453 /* sctpimpguide-05 Section 2.12.2 4454 * The sender of the SHUTDOWN MAY also start an overall guard timer 4455 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4456 */ 4457 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4458 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4459 4460 disposition = SCTP_DISPOSITION_CONSUME; 4461 if (sctp_outq_is_empty(&asoc->outqueue)) { 4462 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4463 arg, commands); 4464 } 4465 return disposition; 4466 } 4467 4468 /* 4469 * Process the ABORT primitive. 4470 * 4471 * Section: 10.1: 4472 * C) Abort 4473 * 4474 * Format: Abort(association id [, cause code]) 4475 * -> result 4476 * 4477 * Ungracefully closes an association. Any locally queued user data 4478 * will be discarded and an ABORT chunk is sent to the peer. A success code 4479 * will be returned on successful abortion of the association. If 4480 * attempting to abort the association results in a failure, an error 4481 * code shall be returned. 4482 * 4483 * Mandatory attributes: 4484 * 4485 * o association id - local handle to the SCTP association 4486 * 4487 * Optional attributes: 4488 * 4489 * o cause code - reason of the abort to be passed to the peer 4490 * 4491 * None. 4492 * 4493 * The return value is the disposition. 4494 */ 4495 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4496 const struct sctp_endpoint *ep, 4497 const struct sctp_association *asoc, 4498 const sctp_subtype_t type, 4499 void *arg, 4500 sctp_cmd_seq_t *commands) 4501 { 4502 /* From 9.1 Abort of an Association 4503 * Upon receipt of the ABORT primitive from its upper 4504 * layer, the endpoint enters CLOSED state and 4505 * discard all outstanding data has been 4506 * acknowledged by its peer. The endpoint accepts no new data 4507 * from its upper layer, but retransmits data to the far end 4508 * if necessary to fill gaps. 4509 */ 4510 struct sctp_chunk *abort = arg; 4511 sctp_disposition_t retval; 4512 4513 retval = SCTP_DISPOSITION_CONSUME; 4514 4515 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4516 4517 /* Even if we can't send the ABORT due to low memory delete the 4518 * TCB. This is a departure from our typical NOMEM handling. 4519 */ 4520 4521 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4522 SCTP_ERROR(ECONNABORTED)); 4523 /* Delete the established association. */ 4524 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4525 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4526 4527 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4528 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4529 4530 return retval; 4531 } 4532 4533 /* We tried an illegal operation on an association which is closed. */ 4534 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4535 const struct sctp_association *asoc, 4536 const sctp_subtype_t type, 4537 void *arg, 4538 sctp_cmd_seq_t *commands) 4539 { 4540 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4541 return SCTP_DISPOSITION_CONSUME; 4542 } 4543 4544 /* We tried an illegal operation on an association which is shutting 4545 * down. 4546 */ 4547 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4548 const struct sctp_association *asoc, 4549 const sctp_subtype_t type, 4550 void *arg, 4551 sctp_cmd_seq_t *commands) 4552 { 4553 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4554 SCTP_ERROR(-ESHUTDOWN)); 4555 return SCTP_DISPOSITION_CONSUME; 4556 } 4557 4558 /* 4559 * sctp_cookie_wait_prm_shutdown 4560 * 4561 * Section: 4 Note: 2 4562 * Verification Tag: 4563 * Inputs 4564 * (endpoint, asoc) 4565 * 4566 * The RFC does not explicitly address this issue, but is the route through the 4567 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4568 * 4569 * Outputs 4570 * (timers) 4571 */ 4572 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4573 const struct sctp_endpoint *ep, 4574 const struct sctp_association *asoc, 4575 const sctp_subtype_t type, 4576 void *arg, 4577 sctp_cmd_seq_t *commands) 4578 { 4579 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4580 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4581 4582 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4583 SCTP_STATE(SCTP_STATE_CLOSED)); 4584 4585 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4586 4587 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4588 4589 return SCTP_DISPOSITION_DELETE_TCB; 4590 } 4591 4592 /* 4593 * sctp_cookie_echoed_prm_shutdown 4594 * 4595 * Section: 4 Note: 2 4596 * Verification Tag: 4597 * Inputs 4598 * (endpoint, asoc) 4599 * 4600 * The RFC does not explcitly address this issue, but is the route through the 4601 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4602 * 4603 * Outputs 4604 * (timers) 4605 */ 4606 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4607 const struct sctp_endpoint *ep, 4608 const struct sctp_association *asoc, 4609 const sctp_subtype_t type, 4610 void *arg, sctp_cmd_seq_t *commands) 4611 { 4612 /* There is a single T1 timer, so we should be able to use 4613 * common function with the COOKIE-WAIT state. 4614 */ 4615 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4616 } 4617 4618 /* 4619 * sctp_sf_cookie_wait_prm_abort 4620 * 4621 * Section: 4 Note: 2 4622 * Verification Tag: 4623 * Inputs 4624 * (endpoint, asoc) 4625 * 4626 * The RFC does not explicitly address this issue, but is the route through the 4627 * state table when someone issues an abort while in COOKIE_WAIT state. 4628 * 4629 * Outputs 4630 * (timers) 4631 */ 4632 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4633 const struct sctp_endpoint *ep, 4634 const struct sctp_association *asoc, 4635 const sctp_subtype_t type, 4636 void *arg, 4637 sctp_cmd_seq_t *commands) 4638 { 4639 struct sctp_chunk *abort = arg; 4640 sctp_disposition_t retval; 4641 4642 /* Stop T1-init timer */ 4643 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4644 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4645 retval = SCTP_DISPOSITION_CONSUME; 4646 4647 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4648 4649 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4650 SCTP_STATE(SCTP_STATE_CLOSED)); 4651 4652 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4653 4654 /* Even if we can't send the ABORT due to low memory delete the 4655 * TCB. This is a departure from our typical NOMEM handling. 4656 */ 4657 4658 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4659 SCTP_ERROR(ECONNREFUSED)); 4660 /* Delete the established association. */ 4661 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4662 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4663 4664 return retval; 4665 } 4666 4667 /* 4668 * sctp_sf_cookie_echoed_prm_abort 4669 * 4670 * Section: 4 Note: 3 4671 * Verification Tag: 4672 * Inputs 4673 * (endpoint, asoc) 4674 * 4675 * The RFC does not explcitly address this issue, but is the route through the 4676 * state table when someone issues an abort while in COOKIE_ECHOED state. 4677 * 4678 * Outputs 4679 * (timers) 4680 */ 4681 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4682 const struct sctp_endpoint *ep, 4683 const struct sctp_association *asoc, 4684 const sctp_subtype_t type, 4685 void *arg, 4686 sctp_cmd_seq_t *commands) 4687 { 4688 /* There is a single T1 timer, so we should be able to use 4689 * common function with the COOKIE-WAIT state. 4690 */ 4691 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4692 } 4693 4694 /* 4695 * sctp_sf_shutdown_pending_prm_abort 4696 * 4697 * Inputs 4698 * (endpoint, asoc) 4699 * 4700 * The RFC does not explicitly address this issue, but is the route through the 4701 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4702 * 4703 * Outputs 4704 * (timers) 4705 */ 4706 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4707 const struct sctp_endpoint *ep, 4708 const struct sctp_association *asoc, 4709 const sctp_subtype_t type, 4710 void *arg, 4711 sctp_cmd_seq_t *commands) 4712 { 4713 /* Stop the T5-shutdown guard timer. */ 4714 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4715 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4716 4717 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4718 } 4719 4720 /* 4721 * sctp_sf_shutdown_sent_prm_abort 4722 * 4723 * Inputs 4724 * (endpoint, asoc) 4725 * 4726 * The RFC does not explicitly address this issue, but is the route through the 4727 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4728 * 4729 * Outputs 4730 * (timers) 4731 */ 4732 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4733 const struct sctp_endpoint *ep, 4734 const struct sctp_association *asoc, 4735 const sctp_subtype_t type, 4736 void *arg, 4737 sctp_cmd_seq_t *commands) 4738 { 4739 /* Stop the T2-shutdown timer. */ 4740 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4741 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4742 4743 /* Stop the T5-shutdown guard timer. */ 4744 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4745 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4746 4747 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4748 } 4749 4750 /* 4751 * sctp_sf_cookie_echoed_prm_abort 4752 * 4753 * Inputs 4754 * (endpoint, asoc) 4755 * 4756 * The RFC does not explcitly address this issue, but is the route through the 4757 * state table when someone issues an abort while in COOKIE_ECHOED state. 4758 * 4759 * Outputs 4760 * (timers) 4761 */ 4762 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4763 const struct sctp_endpoint *ep, 4764 const struct sctp_association *asoc, 4765 const sctp_subtype_t type, 4766 void *arg, 4767 sctp_cmd_seq_t *commands) 4768 { 4769 /* The same T2 timer, so we should be able to use 4770 * common function with the SHUTDOWN-SENT state. 4771 */ 4772 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4773 } 4774 4775 /* 4776 * Process the REQUESTHEARTBEAT primitive 4777 * 4778 * 10.1 ULP-to-SCTP 4779 * J) Request Heartbeat 4780 * 4781 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4782 * 4783 * -> result 4784 * 4785 * Instructs the local endpoint to perform a HeartBeat on the specified 4786 * destination transport address of the given association. The returned 4787 * result should indicate whether the transmission of the HEARTBEAT 4788 * chunk to the destination address is successful. 4789 * 4790 * Mandatory attributes: 4791 * 4792 * o association id - local handle to the SCTP association 4793 * 4794 * o destination transport address - the transport address of the 4795 * association on which a heartbeat should be issued. 4796 */ 4797 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4798 const struct sctp_endpoint *ep, 4799 const struct sctp_association *asoc, 4800 const sctp_subtype_t type, 4801 void *arg, 4802 sctp_cmd_seq_t *commands) 4803 { 4804 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 4805 (struct sctp_transport *)arg, commands)) 4806 return SCTP_DISPOSITION_NOMEM; 4807 4808 /* 4809 * RFC 2960 (bis), section 8.3 4810 * 4811 * D) Request an on-demand HEARTBEAT on a specific destination 4812 * transport address of a given association. 4813 * 4814 * The endpoint should increment the respective error counter of 4815 * the destination transport address each time a HEARTBEAT is sent 4816 * to that address and not acknowledged within one RTO. 4817 * 4818 */ 4819 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 4820 SCTP_TRANSPORT(arg)); 4821 return SCTP_DISPOSITION_CONSUME; 4822 } 4823 4824 /* 4825 * ADDIP Section 4.1 ASCONF Chunk Procedures 4826 * When an endpoint has an ASCONF signaled change to be sent to the 4827 * remote endpoint it should do A1 to A9 4828 */ 4829 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 4830 const struct sctp_association *asoc, 4831 const sctp_subtype_t type, 4832 void *arg, 4833 sctp_cmd_seq_t *commands) 4834 { 4835 struct sctp_chunk *chunk = arg; 4836 4837 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4838 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4839 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4840 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4841 return SCTP_DISPOSITION_CONSUME; 4842 } 4843 4844 /* 4845 * Ignore the primitive event 4846 * 4847 * The return value is the disposition of the primitive. 4848 */ 4849 sctp_disposition_t sctp_sf_ignore_primitive( 4850 const struct sctp_endpoint *ep, 4851 const struct sctp_association *asoc, 4852 const sctp_subtype_t type, 4853 void *arg, 4854 sctp_cmd_seq_t *commands) 4855 { 4856 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 4857 return SCTP_DISPOSITION_DISCARD; 4858 } 4859 4860 /*************************************************************************** 4861 * These are the state functions for the OTHER events. 4862 ***************************************************************************/ 4863 4864 /* 4865 * Start the shutdown negotiation. 4866 * 4867 * From Section 9.2: 4868 * Once all its outstanding data has been acknowledged, the endpoint 4869 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 4870 * TSN Ack field the last sequential TSN it has received from the peer. 4871 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 4872 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 4873 * with the updated last sequential TSN received from its peer. 4874 * 4875 * The return value is the disposition. 4876 */ 4877 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 4878 const struct sctp_endpoint *ep, 4879 const struct sctp_association *asoc, 4880 const sctp_subtype_t type, 4881 void *arg, 4882 sctp_cmd_seq_t *commands) 4883 { 4884 struct sctp_chunk *reply; 4885 4886 /* Once all its outstanding data has been acknowledged, the 4887 * endpoint shall send a SHUTDOWN chunk to its peer including 4888 * in the Cumulative TSN Ack field the last sequential TSN it 4889 * has received from the peer. 4890 */ 4891 reply = sctp_make_shutdown(asoc, NULL); 4892 if (!reply) 4893 goto nomem; 4894 4895 /* Set the transport for the SHUTDOWN chunk and the timeout for the 4896 * T2-shutdown timer. 4897 */ 4898 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4899 4900 /* It shall then start the T2-shutdown timer */ 4901 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4902 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4903 4904 if (asoc->autoclose) 4905 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4906 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4907 4908 /* and enter the SHUTDOWN-SENT state. */ 4909 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4910 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 4911 4912 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4913 * 4914 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4915 * or SHUTDOWN-ACK. 4916 */ 4917 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4918 4919 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4920 4921 return SCTP_DISPOSITION_CONSUME; 4922 4923 nomem: 4924 return SCTP_DISPOSITION_NOMEM; 4925 } 4926 4927 /* 4928 * Generate a SHUTDOWN ACK now that everything is SACK'd. 4929 * 4930 * From Section 9.2: 4931 * 4932 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4933 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 4934 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 4935 * endpoint must re-send the SHUTDOWN ACK. 4936 * 4937 * The return value is the disposition. 4938 */ 4939 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 4940 const struct sctp_endpoint *ep, 4941 const struct sctp_association *asoc, 4942 const sctp_subtype_t type, 4943 void *arg, 4944 sctp_cmd_seq_t *commands) 4945 { 4946 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 4947 struct sctp_chunk *reply; 4948 4949 /* There are 2 ways of getting here: 4950 * 1) called in response to a SHUTDOWN chunk 4951 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 4952 * 4953 * For the case (2), the arg parameter is set to NULL. We need 4954 * to check that we have a chunk before accessing it's fields. 4955 */ 4956 if (chunk) { 4957 if (!sctp_vtag_verify(chunk, asoc)) 4958 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4959 4960 /* Make sure that the SHUTDOWN chunk has a valid length. */ 4961 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 4962 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4963 commands); 4964 } 4965 4966 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4967 * shall send a SHUTDOWN ACK ... 4968 */ 4969 reply = sctp_make_shutdown_ack(asoc, chunk); 4970 if (!reply) 4971 goto nomem; 4972 4973 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 4974 * the T2-shutdown timer. 4975 */ 4976 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4977 4978 /* and start/restart a T2-shutdown timer of its own, */ 4979 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4980 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4981 4982 if (asoc->autoclose) 4983 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4984 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4985 4986 /* Enter the SHUTDOWN-ACK-SENT state. */ 4987 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4988 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 4989 4990 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4991 * 4992 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4993 * or SHUTDOWN-ACK. 4994 */ 4995 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4996 4997 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4998 4999 return SCTP_DISPOSITION_CONSUME; 5000 5001 nomem: 5002 return SCTP_DISPOSITION_NOMEM; 5003 } 5004 5005 /* 5006 * Ignore the event defined as other 5007 * 5008 * The return value is the disposition of the event. 5009 */ 5010 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 5011 const struct sctp_association *asoc, 5012 const sctp_subtype_t type, 5013 void *arg, 5014 sctp_cmd_seq_t *commands) 5015 { 5016 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5017 return SCTP_DISPOSITION_DISCARD; 5018 } 5019 5020 /************************************************************ 5021 * These are the state functions for handling timeout events. 5022 ************************************************************/ 5023 5024 /* 5025 * RTX Timeout 5026 * 5027 * Section: 6.3.3 Handle T3-rtx Expiration 5028 * 5029 * Whenever the retransmission timer T3-rtx expires for a destination 5030 * address, do the following: 5031 * [See below] 5032 * 5033 * The return value is the disposition of the chunk. 5034 */ 5035 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 5036 const struct sctp_association *asoc, 5037 const sctp_subtype_t type, 5038 void *arg, 5039 sctp_cmd_seq_t *commands) 5040 { 5041 struct sctp_transport *transport = arg; 5042 5043 SCTP_INC_STATS(SCTP_MIB_T3_RTX_EXPIREDS); 5044 5045 if (asoc->overall_error_count >= asoc->max_retrans) { 5046 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5047 SCTP_ERROR(ETIMEDOUT)); 5048 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5049 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5050 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5051 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5052 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5053 return SCTP_DISPOSITION_DELETE_TCB; 5054 } 5055 5056 /* E1) For the destination address for which the timer 5057 * expires, adjust its ssthresh with rules defined in Section 5058 * 7.2.3 and set the cwnd <- MTU. 5059 */ 5060 5061 /* E2) For the destination address for which the timer 5062 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5063 * maximum value discussed in rule C7 above (RTO.max) may be 5064 * used to provide an upper bound to this doubling operation. 5065 */ 5066 5067 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5068 * outstanding DATA chunks for the address for which the 5069 * T3-rtx has expired will fit into a single packet, subject 5070 * to the MTU constraint for the path corresponding to the 5071 * destination transport address to which the retransmission 5072 * is being sent (this may be different from the address for 5073 * which the timer expires [see Section 6.4]). Call this 5074 * value K. Bundle and retransmit those K DATA chunks in a 5075 * single packet to the destination endpoint. 5076 * 5077 * Note: Any DATA chunks that were sent to the address for 5078 * which the T3-rtx timer expired but did not fit in one MTU 5079 * (rule E3 above), should be marked for retransmission and 5080 * sent as soon as cwnd allows (normally when a SACK arrives). 5081 */ 5082 5083 /* Do some failure management (Section 8.2). */ 5084 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5085 5086 /* NB: Rules E4 and F1 are implicit in R1. */ 5087 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5088 5089 return SCTP_DISPOSITION_CONSUME; 5090 } 5091 5092 /* 5093 * Generate delayed SACK on timeout 5094 * 5095 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5096 * 5097 * The guidelines on delayed acknowledgement algorithm specified in 5098 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5099 * acknowledgement SHOULD be generated for at least every second packet 5100 * (not every second DATA chunk) received, and SHOULD be generated 5101 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5102 * some situations it may be beneficial for an SCTP transmitter to be 5103 * more conservative than the algorithms detailed in this document 5104 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5105 * the following algorithms allow. 5106 */ 5107 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 5108 const struct sctp_association *asoc, 5109 const sctp_subtype_t type, 5110 void *arg, 5111 sctp_cmd_seq_t *commands) 5112 { 5113 SCTP_INC_STATS(SCTP_MIB_DELAY_SACK_EXPIREDS); 5114 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5115 return SCTP_DISPOSITION_CONSUME; 5116 } 5117 5118 /* 5119 * sctp_sf_t1_init_timer_expire 5120 * 5121 * Section: 4 Note: 2 5122 * Verification Tag: 5123 * Inputs 5124 * (endpoint, asoc) 5125 * 5126 * RFC 2960 Section 4 Notes 5127 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5128 * and re-start the T1-init timer without changing state. This MUST 5129 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5130 * endpoint MUST abort the initialization process and report the 5131 * error to SCTP user. 5132 * 5133 * Outputs 5134 * (timers, events) 5135 * 5136 */ 5137 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 5138 const struct sctp_association *asoc, 5139 const sctp_subtype_t type, 5140 void *arg, 5141 sctp_cmd_seq_t *commands) 5142 { 5143 struct sctp_chunk *repl = NULL; 5144 struct sctp_bind_addr *bp; 5145 int attempts = asoc->init_err_counter + 1; 5146 5147 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5148 SCTP_INC_STATS(SCTP_MIB_T1_INIT_EXPIREDS); 5149 5150 if (attempts <= asoc->max_init_attempts) { 5151 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5152 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5153 if (!repl) 5154 return SCTP_DISPOSITION_NOMEM; 5155 5156 /* Choose transport for INIT. */ 5157 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5158 SCTP_CHUNK(repl)); 5159 5160 /* Issue a sideeffect to do the needed accounting. */ 5161 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5162 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5163 5164 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5165 } else { 5166 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5167 " max_init_attempts: %d\n", 5168 attempts, asoc->max_init_attempts); 5169 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5170 SCTP_ERROR(ETIMEDOUT)); 5171 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5172 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5173 return SCTP_DISPOSITION_DELETE_TCB; 5174 } 5175 5176 return SCTP_DISPOSITION_CONSUME; 5177 } 5178 5179 /* 5180 * sctp_sf_t1_cookie_timer_expire 5181 * 5182 * Section: 4 Note: 2 5183 * Verification Tag: 5184 * Inputs 5185 * (endpoint, asoc) 5186 * 5187 * RFC 2960 Section 4 Notes 5188 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5189 * COOKIE ECHO and re-start the T1-cookie timer without changing 5190 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5191 * After that, the endpoint MUST abort the initialization process and 5192 * report the error to SCTP user. 5193 * 5194 * Outputs 5195 * (timers, events) 5196 * 5197 */ 5198 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 5199 const struct sctp_association *asoc, 5200 const sctp_subtype_t type, 5201 void *arg, 5202 sctp_cmd_seq_t *commands) 5203 { 5204 struct sctp_chunk *repl = NULL; 5205 int attempts = asoc->init_err_counter + 1; 5206 5207 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5208 SCTP_INC_STATS(SCTP_MIB_T1_COOKIE_EXPIREDS); 5209 5210 if (attempts <= asoc->max_init_attempts) { 5211 repl = sctp_make_cookie_echo(asoc, NULL); 5212 if (!repl) 5213 return SCTP_DISPOSITION_NOMEM; 5214 5215 /* Issue a sideeffect to do the needed accounting. */ 5216 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5217 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5218 5219 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5220 } else { 5221 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5222 SCTP_ERROR(ETIMEDOUT)); 5223 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5224 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5225 return SCTP_DISPOSITION_DELETE_TCB; 5226 } 5227 5228 return SCTP_DISPOSITION_CONSUME; 5229 } 5230 5231 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5232 * with the updated last sequential TSN received from its peer. 5233 * 5234 * An endpoint should limit the number of retransmissions of the 5235 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5236 * If this threshold is exceeded the endpoint should destroy the TCB and 5237 * MUST report the peer endpoint unreachable to the upper layer (and 5238 * thus the association enters the CLOSED state). The reception of any 5239 * packet from its peer (i.e. as the peer sends all of its queued DATA 5240 * chunks) should clear the endpoint's retransmission count and restart 5241 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5242 * all of its queued DATA chunks that have not yet been sent. 5243 */ 5244 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 5245 const struct sctp_association *asoc, 5246 const sctp_subtype_t type, 5247 void *arg, 5248 sctp_cmd_seq_t *commands) 5249 { 5250 struct sctp_chunk *reply = NULL; 5251 5252 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 5253 SCTP_INC_STATS(SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5254 5255 if (asoc->overall_error_count >= asoc->max_retrans) { 5256 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5257 SCTP_ERROR(ETIMEDOUT)); 5258 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5259 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5260 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5261 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5262 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5263 return SCTP_DISPOSITION_DELETE_TCB; 5264 } 5265 5266 switch (asoc->state) { 5267 case SCTP_STATE_SHUTDOWN_SENT: 5268 reply = sctp_make_shutdown(asoc, NULL); 5269 break; 5270 5271 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5272 reply = sctp_make_shutdown_ack(asoc, NULL); 5273 break; 5274 5275 default: 5276 BUG(); 5277 break; 5278 } 5279 5280 if (!reply) 5281 goto nomem; 5282 5283 /* Do some failure management (Section 8.2). */ 5284 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5285 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5286 5287 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5288 * the T2-shutdown timer. 5289 */ 5290 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5291 5292 /* Restart the T2-shutdown timer. */ 5293 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5294 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5295 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5296 return SCTP_DISPOSITION_CONSUME; 5297 5298 nomem: 5299 return SCTP_DISPOSITION_NOMEM; 5300 } 5301 5302 /* 5303 * ADDIP Section 4.1 ASCONF CHunk Procedures 5304 * If the T4 RTO timer expires the endpoint should do B1 to B5 5305 */ 5306 sctp_disposition_t sctp_sf_t4_timer_expire( 5307 const struct sctp_endpoint *ep, 5308 const struct sctp_association *asoc, 5309 const sctp_subtype_t type, 5310 void *arg, 5311 sctp_cmd_seq_t *commands) 5312 { 5313 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5314 struct sctp_transport *transport = chunk->transport; 5315 5316 SCTP_INC_STATS(SCTP_MIB_T4_RTO_EXPIREDS); 5317 5318 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5319 * detection on the appropriate destination address as defined in 5320 * RFC2960 [5] section 8.1 and 8.2. 5321 */ 5322 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5323 5324 /* Reconfig T4 timer and transport. */ 5325 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5326 5327 /* ADDIP 4.1 B2) Increment the association error counters and perform 5328 * endpoint failure detection on the association as defined in 5329 * RFC2960 [5] section 8.1 and 8.2. 5330 * association error counter is incremented in SCTP_CMD_STRIKE. 5331 */ 5332 if (asoc->overall_error_count >= asoc->max_retrans) { 5333 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5334 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5335 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5336 SCTP_ERROR(ETIMEDOUT)); 5337 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5338 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5339 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5340 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 5341 return SCTP_DISPOSITION_ABORT; 5342 } 5343 5344 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5345 * the ASCONF chunk was sent by doubling the RTO timer value. 5346 * This is done in SCTP_CMD_STRIKE. 5347 */ 5348 5349 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5350 * choose an alternate destination address (please refer to RFC2960 5351 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5352 * chunk, it MUST be the same (including its serial number) as the last 5353 * ASCONF sent. 5354 */ 5355 sctp_chunk_hold(asoc->addip_last_asconf); 5356 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5357 SCTP_CHUNK(asoc->addip_last_asconf)); 5358 5359 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5360 * destination is selected, then the RTO used will be that of the new 5361 * destination address. 5362 */ 5363 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5364 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5365 5366 return SCTP_DISPOSITION_CONSUME; 5367 } 5368 5369 /* sctpimpguide-05 Section 2.12.2 5370 * The sender of the SHUTDOWN MAY also start an overall guard timer 5371 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5372 * At the expiration of this timer the sender SHOULD abort the association 5373 * by sending an ABORT chunk. 5374 */ 5375 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 5376 const struct sctp_association *asoc, 5377 const sctp_subtype_t type, 5378 void *arg, 5379 sctp_cmd_seq_t *commands) 5380 { 5381 struct sctp_chunk *reply = NULL; 5382 5383 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5384 SCTP_INC_STATS(SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5385 5386 reply = sctp_make_abort(asoc, NULL, 0); 5387 if (!reply) 5388 goto nomem; 5389 5390 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5391 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5392 SCTP_ERROR(ETIMEDOUT)); 5393 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5394 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5395 5396 return SCTP_DISPOSITION_DELETE_TCB; 5397 nomem: 5398 return SCTP_DISPOSITION_NOMEM; 5399 } 5400 5401 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5402 * the association is automatically closed by starting the shutdown process. 5403 * The work that needs to be done is same as when SHUTDOWN is initiated by 5404 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5405 */ 5406 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5407 const struct sctp_endpoint *ep, 5408 const struct sctp_association *asoc, 5409 const sctp_subtype_t type, 5410 void *arg, 5411 sctp_cmd_seq_t *commands) 5412 { 5413 int disposition; 5414 5415 SCTP_INC_STATS(SCTP_MIB_AUTOCLOSE_EXPIREDS); 5416 5417 /* From 9.2 Shutdown of an Association 5418 * Upon receipt of the SHUTDOWN primitive from its upper 5419 * layer, the endpoint enters SHUTDOWN-PENDING state and 5420 * remains there until all outstanding data has been 5421 * acknowledged by its peer. The endpoint accepts no new data 5422 * from its upper layer, but retransmits data to the far end 5423 * if necessary to fill gaps. 5424 */ 5425 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5426 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5427 5428 /* sctpimpguide-05 Section 2.12.2 5429 * The sender of the SHUTDOWN MAY also start an overall guard timer 5430 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5431 */ 5432 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5433 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5434 disposition = SCTP_DISPOSITION_CONSUME; 5435 if (sctp_outq_is_empty(&asoc->outqueue)) { 5436 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 5437 arg, commands); 5438 } 5439 return disposition; 5440 } 5441 5442 /***************************************************************************** 5443 * These are sa state functions which could apply to all types of events. 5444 ****************************************************************************/ 5445 5446 /* 5447 * This table entry is not implemented. 5448 * 5449 * Inputs 5450 * (endpoint, asoc, chunk) 5451 * 5452 * The return value is the disposition of the chunk. 5453 */ 5454 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 5455 const struct sctp_association *asoc, 5456 const sctp_subtype_t type, 5457 void *arg, 5458 sctp_cmd_seq_t *commands) 5459 { 5460 return SCTP_DISPOSITION_NOT_IMPL; 5461 } 5462 5463 /* 5464 * This table entry represents a bug. 5465 * 5466 * Inputs 5467 * (endpoint, asoc, chunk) 5468 * 5469 * The return value is the disposition of the chunk. 5470 */ 5471 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 5472 const struct sctp_association *asoc, 5473 const sctp_subtype_t type, 5474 void *arg, 5475 sctp_cmd_seq_t *commands) 5476 { 5477 return SCTP_DISPOSITION_BUG; 5478 } 5479 5480 /* 5481 * This table entry represents the firing of a timer in the wrong state. 5482 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5483 * when the association is in the wrong state. This event should 5484 * be ignored, so as to prevent any rearming of the timer. 5485 * 5486 * Inputs 5487 * (endpoint, asoc, chunk) 5488 * 5489 * The return value is the disposition of the chunk. 5490 */ 5491 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 5492 const struct sctp_association *asoc, 5493 const sctp_subtype_t type, 5494 void *arg, 5495 sctp_cmd_seq_t *commands) 5496 { 5497 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5498 return SCTP_DISPOSITION_CONSUME; 5499 } 5500 5501 /******************************************************************** 5502 * 2nd Level Abstractions 5503 ********************************************************************/ 5504 5505 /* Pull the SACK chunk based on the SACK header. */ 5506 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5507 { 5508 struct sctp_sackhdr *sack; 5509 unsigned int len; 5510 __u16 num_blocks; 5511 __u16 num_dup_tsns; 5512 5513 /* Protect ourselves from reading too far into 5514 * the skb from a bogus sender. 5515 */ 5516 sack = (struct sctp_sackhdr *) chunk->skb->data; 5517 5518 num_blocks = ntohs(sack->num_gap_ack_blocks); 5519 num_dup_tsns = ntohs(sack->num_dup_tsns); 5520 len = sizeof(struct sctp_sackhdr); 5521 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5522 if (len > chunk->skb->len) 5523 return NULL; 5524 5525 skb_pull(chunk->skb, len); 5526 5527 return sack; 5528 } 5529 5530 /* Create an ABORT packet to be sent as a response, with the specified 5531 * error causes. 5532 */ 5533 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5534 const struct sctp_association *asoc, 5535 struct sctp_chunk *chunk, 5536 const void *payload, 5537 size_t paylen) 5538 { 5539 struct sctp_packet *packet; 5540 struct sctp_chunk *abort; 5541 5542 packet = sctp_ootb_pkt_new(asoc, chunk); 5543 5544 if (packet) { 5545 /* Make an ABORT. 5546 * The T bit will be set if the asoc is NULL. 5547 */ 5548 abort = sctp_make_abort(asoc, chunk, paylen); 5549 if (!abort) { 5550 sctp_ootb_pkt_free(packet); 5551 return NULL; 5552 } 5553 5554 /* Reflect vtag if T-Bit is set */ 5555 if (sctp_test_T_bit(abort)) 5556 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5557 5558 /* Add specified error causes, i.e., payload, to the 5559 * end of the chunk. 5560 */ 5561 sctp_addto_chunk(abort, paylen, payload); 5562 5563 /* Set the skb to the belonging sock for accounting. */ 5564 abort->skb->sk = ep->base.sk; 5565 5566 sctp_packet_append_chunk(packet, abort); 5567 5568 } 5569 5570 return packet; 5571 } 5572 5573 /* Allocate a packet for responding in the OOTB conditions. */ 5574 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5575 const struct sctp_chunk *chunk) 5576 { 5577 struct sctp_packet *packet; 5578 struct sctp_transport *transport; 5579 __u16 sport; 5580 __u16 dport; 5581 __u32 vtag; 5582 5583 /* Get the source and destination port from the inbound packet. */ 5584 sport = ntohs(chunk->sctp_hdr->dest); 5585 dport = ntohs(chunk->sctp_hdr->source); 5586 5587 /* The V-tag is going to be the same as the inbound packet if no 5588 * association exists, otherwise, use the peer's vtag. 5589 */ 5590 if (asoc) { 5591 /* Special case the INIT-ACK as there is no peer's vtag 5592 * yet. 5593 */ 5594 switch(chunk->chunk_hdr->type) { 5595 case SCTP_CID_INIT_ACK: 5596 { 5597 sctp_initack_chunk_t *initack; 5598 5599 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5600 vtag = ntohl(initack->init_hdr.init_tag); 5601 break; 5602 } 5603 default: 5604 vtag = asoc->peer.i.init_tag; 5605 break; 5606 } 5607 } else { 5608 /* Special case the INIT and stale COOKIE_ECHO as there is no 5609 * vtag yet. 5610 */ 5611 switch(chunk->chunk_hdr->type) { 5612 case SCTP_CID_INIT: 5613 { 5614 sctp_init_chunk_t *init; 5615 5616 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5617 vtag = ntohl(init->init_hdr.init_tag); 5618 break; 5619 } 5620 default: 5621 vtag = ntohl(chunk->sctp_hdr->vtag); 5622 break; 5623 } 5624 } 5625 5626 /* Make a transport for the bucket, Eliza... */ 5627 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5628 if (!transport) 5629 goto nomem; 5630 5631 /* Cache a route for the transport with the chunk's destination as 5632 * the source address. 5633 */ 5634 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5635 sctp_sk(sctp_get_ctl_sock())); 5636 5637 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5638 packet = sctp_packet_config(packet, vtag, 0); 5639 5640 return packet; 5641 5642 nomem: 5643 return NULL; 5644 } 5645 5646 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5647 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5648 { 5649 sctp_transport_free(packet->transport); 5650 } 5651 5652 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5653 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5654 const struct sctp_association *asoc, 5655 const struct sctp_chunk *chunk, 5656 sctp_cmd_seq_t *commands, 5657 struct sctp_chunk *err_chunk) 5658 { 5659 struct sctp_packet *packet; 5660 5661 if (err_chunk) { 5662 packet = sctp_ootb_pkt_new(asoc, chunk); 5663 if (packet) { 5664 struct sctp_signed_cookie *cookie; 5665 5666 /* Override the OOTB vtag from the cookie. */ 5667 cookie = chunk->subh.cookie_hdr; 5668 packet->vtag = cookie->c.peer_vtag; 5669 5670 /* Set the skb to the belonging sock for accounting. */ 5671 err_chunk->skb->sk = ep->base.sk; 5672 sctp_packet_append_chunk(packet, err_chunk); 5673 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5674 SCTP_PACKET(packet)); 5675 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5676 } else 5677 sctp_chunk_free (err_chunk); 5678 } 5679 } 5680 5681 5682 /* Process a data chunk */ 5683 static int sctp_eat_data(const struct sctp_association *asoc, 5684 struct sctp_chunk *chunk, 5685 sctp_cmd_seq_t *commands) 5686 { 5687 sctp_datahdr_t *data_hdr; 5688 struct sctp_chunk *err; 5689 size_t datalen; 5690 sctp_verb_t deliver; 5691 int tmp; 5692 __u32 tsn; 5693 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 5694 struct sock *sk = asoc->base.sk; 5695 5696 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5697 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5698 5699 tsn = ntohl(data_hdr->tsn); 5700 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5701 5702 /* ASSERT: Now skb->data is really the user data. */ 5703 5704 /* Process ECN based congestion. 5705 * 5706 * Since the chunk structure is reused for all chunks within 5707 * a packet, we use ecn_ce_done to track if we've already 5708 * done CE processing for this packet. 5709 * 5710 * We need to do ECN processing even if we plan to discard the 5711 * chunk later. 5712 */ 5713 5714 if (!chunk->ecn_ce_done) { 5715 struct sctp_af *af; 5716 chunk->ecn_ce_done = 1; 5717 5718 af = sctp_get_af_specific( 5719 ipver2af(ip_hdr(chunk->skb)->version)); 5720 5721 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5722 /* Do real work as sideffect. */ 5723 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5724 SCTP_U32(tsn)); 5725 } 5726 } 5727 5728 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5729 if (tmp < 0) { 5730 /* The TSN is too high--silently discard the chunk and 5731 * count on it getting retransmitted later. 5732 */ 5733 return SCTP_IERROR_HIGH_TSN; 5734 } else if (tmp > 0) { 5735 /* This is a duplicate. Record it. */ 5736 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5737 return SCTP_IERROR_DUP_TSN; 5738 } 5739 5740 /* This is a new TSN. */ 5741 5742 /* Discard if there is no room in the receive window. 5743 * Actually, allow a little bit of overflow (up to a MTU). 5744 */ 5745 datalen = ntohs(chunk->chunk_hdr->length); 5746 datalen -= sizeof(sctp_data_chunk_t); 5747 5748 deliver = SCTP_CMD_CHUNK_ULP; 5749 5750 /* Think about partial delivery. */ 5751 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5752 5753 /* Even if we don't accept this chunk there is 5754 * memory pressure. 5755 */ 5756 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5757 } 5758 5759 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5760 * seems a bit troublesome in that frag_point varies based on 5761 * PMTU. In cases, such as loopback, this might be a rather 5762 * large spill over. 5763 */ 5764 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 5765 (datalen > asoc->rwnd + asoc->frag_point))) { 5766 5767 /* If this is the next TSN, consider reneging to make 5768 * room. Note: Playing nice with a confused sender. A 5769 * malicious sender can still eat up all our buffer 5770 * space and in the future we may want to detect and 5771 * do more drastic reneging. 5772 */ 5773 if (sctp_tsnmap_has_gap(map) && 5774 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5775 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5776 deliver = SCTP_CMD_RENEGE; 5777 } else { 5778 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5779 "rwnd: %d\n", tsn, datalen, 5780 asoc->rwnd); 5781 return SCTP_IERROR_IGNORE_TSN; 5782 } 5783 } 5784 5785 /* 5786 * Also try to renege to limit our memory usage in the event that 5787 * we are under memory pressure 5788 * If we can't renege, don't worry about it, the sk_stream_rmem_schedule 5789 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 5790 * memory usage too much 5791 */ 5792 if (*sk->sk_prot_creator->memory_pressure) { 5793 if (sctp_tsnmap_has_gap(map) && 5794 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 5795 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 5796 deliver = SCTP_CMD_RENEGE; 5797 } 5798 } 5799 5800 /* 5801 * Section 3.3.10.9 No User Data (9) 5802 * 5803 * Cause of error 5804 * --------------- 5805 * No User Data: This error cause is returned to the originator of a 5806 * DATA chunk if a received DATA chunk has no user data. 5807 */ 5808 if (unlikely(0 == datalen)) { 5809 err = sctp_make_abort_no_data(asoc, chunk, tsn); 5810 if (err) { 5811 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5812 SCTP_CHUNK(err)); 5813 } 5814 /* We are going to ABORT, so we might as well stop 5815 * processing the rest of the chunks in the packet. 5816 */ 5817 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 5818 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5819 SCTP_ERROR(ECONNABORTED)); 5820 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5821 SCTP_PERR(SCTP_ERROR_NO_DATA)); 5822 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5823 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5824 return SCTP_IERROR_NO_DATA; 5825 } 5826 5827 /* If definately accepting the DATA chunk, record its TSN, otherwise 5828 * wait for renege processing. 5829 */ 5830 if (SCTP_CMD_CHUNK_ULP == deliver) 5831 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 5832 5833 chunk->data_accepted = 1; 5834 5835 /* Note: Some chunks may get overcounted (if we drop) or overcounted 5836 * if we renege and the chunk arrives again. 5837 */ 5838 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 5839 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 5840 else 5841 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 5842 5843 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 5844 * 5845 * If an endpoint receive a DATA chunk with an invalid stream 5846 * identifier, it shall acknowledge the reception of the DATA chunk 5847 * following the normal procedure, immediately send an ERROR chunk 5848 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 5849 * and discard the DATA chunk. 5850 */ 5851 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { 5852 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 5853 &data_hdr->stream, 5854 sizeof(data_hdr->stream)); 5855 if (err) 5856 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5857 SCTP_CHUNK(err)); 5858 return SCTP_IERROR_BAD_STREAM; 5859 } 5860 5861 /* Send the data up to the user. Note: Schedule the 5862 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 5863 * chunk needs the updated rwnd. 5864 */ 5865 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 5866 5867 return SCTP_IERROR_NO_ERROR; 5868 } 5869