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