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 96 /* Small helper function that checks if the chunk length 97 * is of the appropriate length. The 'required_length' argument 98 * is set to be the size of a specific chunk we are testing. 99 * Return Values: 1 = Valid length 100 * 0 = Invalid length 101 * 102 */ 103 static inline int 104 sctp_chunk_length_valid(struct sctp_chunk *chunk, 105 __u16 required_length) 106 { 107 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 108 109 if (unlikely(chunk_length < required_length)) 110 return 0; 111 112 return 1; 113 } 114 115 /********************************************************** 116 * These are the state functions for handling chunk events. 117 **********************************************************/ 118 119 /* 120 * Process the final SHUTDOWN COMPLETE. 121 * 122 * Section: 4 (C) (diagram), 9.2 123 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 124 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 125 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 126 * should stop the T2-shutdown timer and remove all knowledge of the 127 * association (and thus the association enters the CLOSED state). 128 * 129 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 130 * C) Rules for packet carrying SHUTDOWN COMPLETE: 131 * ... 132 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 133 * if the Verification Tag field of the packet matches its own tag and 134 * the T bit is not set 135 * OR 136 * it is set to its peer's tag and the T bit is set in the Chunk 137 * Flags. 138 * Otherwise, the receiver MUST silently discard the packet 139 * and take no further action. An endpoint MUST ignore the 140 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 141 * 142 * Inputs 143 * (endpoint, asoc, chunk) 144 * 145 * Outputs 146 * (asoc, reply_msg, msg_up, timers, counters) 147 * 148 * The return value is the disposition of the chunk. 149 */ 150 sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, 151 const struct sctp_association *asoc, 152 const sctp_subtype_t type, 153 void *arg, 154 sctp_cmd_seq_t *commands) 155 { 156 struct sctp_chunk *chunk = arg; 157 struct sctp_ulpevent *ev; 158 159 /* RFC 2960 6.10 Bundling 160 * 161 * An endpoint MUST NOT bundle INIT, INIT ACK or 162 * SHUTDOWN COMPLETE with any other chunks. 163 */ 164 if (!chunk->singleton) 165 return SCTP_DISPOSITION_VIOLATION; 166 167 if (!sctp_vtag_verify_either(chunk, asoc)) 168 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 169 170 /* RFC 2960 10.2 SCTP-to-ULP 171 * 172 * H) SHUTDOWN COMPLETE notification 173 * 174 * When SCTP completes the shutdown procedures (section 9.2) this 175 * notification is passed to the upper layer. 176 */ 177 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 178 0, 0, 0, GFP_ATOMIC); 179 if (!ev) 180 goto nomem; 181 182 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 183 184 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 185 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 186 * not the chunk should be discarded. If the endpoint is in 187 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 188 * T2-shutdown timer and remove all knowledge of the 189 * association (and thus the association enters the CLOSED 190 * state). 191 */ 192 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 193 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 194 195 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 196 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 197 198 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 199 SCTP_STATE(SCTP_STATE_CLOSED)); 200 201 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 202 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 203 204 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 205 206 return SCTP_DISPOSITION_DELETE_TCB; 207 208 nomem: 209 return SCTP_DISPOSITION_NOMEM; 210 } 211 212 /* 213 * Respond to a normal INIT chunk. 214 * We are the side that is being asked for an association. 215 * 216 * Section: 5.1 Normal Establishment of an Association, B 217 * B) "Z" shall respond immediately with an INIT ACK chunk. The 218 * destination IP address of the INIT ACK MUST be set to the source 219 * IP address of the INIT to which this INIT ACK is responding. In 220 * the response, besides filling in other parameters, "Z" must set the 221 * Verification Tag field to Tag_A, and also provide its own 222 * Verification Tag (Tag_Z) in the Initiate Tag field. 223 * 224 * Verification Tag: Must be 0. 225 * 226 * Inputs 227 * (endpoint, asoc, chunk) 228 * 229 * Outputs 230 * (asoc, reply_msg, msg_up, timers, counters) 231 * 232 * The return value is the disposition of the chunk. 233 */ 234 sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, 235 const struct sctp_association *asoc, 236 const sctp_subtype_t type, 237 void *arg, 238 sctp_cmd_seq_t *commands) 239 { 240 struct sctp_chunk *chunk = arg; 241 struct sctp_chunk *repl; 242 struct sctp_association *new_asoc; 243 struct sctp_chunk *err_chunk; 244 struct sctp_packet *packet; 245 sctp_unrecognized_param_t *unk_param; 246 struct sock *sk; 247 int len; 248 249 /* 6.10 Bundling 250 * An endpoint MUST NOT bundle INIT, INIT ACK or 251 * SHUTDOWN COMPLETE with any other chunks. 252 * 253 * IG Section 2.11.2 254 * Furthermore, we require that the receiver of an INIT chunk MUST 255 * enforce these rules by silently discarding an arriving packet 256 * with an INIT chunk that is bundled with other chunks. 257 */ 258 if (!chunk->singleton) 259 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 260 261 /* If the packet is an OOTB packet which is temporarily on the 262 * control endpoint, respond with an ABORT. 263 */ 264 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 265 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 266 267 sk = ep->base.sk; 268 /* If the endpoint is not listening or if the number of associations 269 * on the TCP-style socket exceed the max backlog, respond with an 270 * ABORT. 271 */ 272 if (!sctp_sstate(sk, LISTENING) || 273 (sctp_style(sk, TCP) && 274 sk_acceptq_is_full(sk))) 275 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 276 277 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 278 * Tag. 279 */ 280 if (chunk->sctp_hdr->vtag != 0) 281 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 282 283 /* Make sure that the INIT chunk has a valid length. 284 * Normally, this would cause an ABORT with a Protocol Violation 285 * error, but since we don't have an association, we'll 286 * just discard the packet. 287 */ 288 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 289 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 290 291 /* Verify the INIT chunk before processing it. */ 292 err_chunk = NULL; 293 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 294 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 295 &err_chunk)) { 296 /* This chunk contains fatal error. It is to be discarded. 297 * Send an ABORT, with causes if there is any. 298 */ 299 if (err_chunk) { 300 packet = sctp_abort_pkt_new(ep, asoc, arg, 301 (__u8 *)(err_chunk->chunk_hdr) + 302 sizeof(sctp_chunkhdr_t), 303 ntohs(err_chunk->chunk_hdr->length) - 304 sizeof(sctp_chunkhdr_t)); 305 306 sctp_chunk_free(err_chunk); 307 308 if (packet) { 309 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 310 SCTP_PACKET(packet)); 311 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 312 return SCTP_DISPOSITION_CONSUME; 313 } else { 314 return SCTP_DISPOSITION_NOMEM; 315 } 316 } else { 317 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 318 commands); 319 } 320 } 321 322 /* Grab the INIT header. */ 323 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 324 325 /* Tag the variable length parameters. */ 326 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 327 328 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 329 if (!new_asoc) 330 goto nomem; 331 332 /* The call, sctp_process_init(), can fail on memory allocation. */ 333 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 334 sctp_source(chunk), 335 (sctp_init_chunk_t *)chunk->chunk_hdr, 336 GFP_ATOMIC)) 337 goto nomem_init; 338 339 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 340 341 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 342 343 /* If there are errors need to be reported for unknown parameters, 344 * make sure to reserve enough room in the INIT ACK for them. 345 */ 346 len = 0; 347 if (err_chunk) 348 len = ntohs(err_chunk->chunk_hdr->length) - 349 sizeof(sctp_chunkhdr_t); 350 351 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 352 goto nomem_ack; 353 354 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 355 if (!repl) 356 goto nomem_ack; 357 358 /* If there are errors need to be reported for unknown parameters, 359 * include them in the outgoing INIT ACK as "Unrecognized parameter" 360 * parameter. 361 */ 362 if (err_chunk) { 363 /* Get the "Unrecognized parameter" parameter(s) out of the 364 * ERROR chunk generated by sctp_verify_init(). Since the 365 * error cause code for "unknown parameter" and the 366 * "Unrecognized parameter" type is the same, we can 367 * construct the parameters in INIT ACK by copying the 368 * ERROR causes over. 369 */ 370 unk_param = (sctp_unrecognized_param_t *) 371 ((__u8 *)(err_chunk->chunk_hdr) + 372 sizeof(sctp_chunkhdr_t)); 373 /* Replace the cause code with the "Unrecognized parameter" 374 * parameter type. 375 */ 376 sctp_addto_chunk(repl, len, unk_param); 377 sctp_chunk_free(err_chunk); 378 } 379 380 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 381 382 /* 383 * Note: After sending out INIT ACK with the State Cookie parameter, 384 * "Z" MUST NOT allocate any resources, nor keep any states for the 385 * new association. Otherwise, "Z" will be vulnerable to resource 386 * attacks. 387 */ 388 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 389 390 return SCTP_DISPOSITION_DELETE_TCB; 391 392 nomem_ack: 393 if (err_chunk) 394 sctp_chunk_free(err_chunk); 395 nomem_init: 396 sctp_association_free(new_asoc); 397 nomem: 398 return SCTP_DISPOSITION_NOMEM; 399 } 400 401 /* 402 * Respond to a normal INIT ACK chunk. 403 * We are the side that is initiating the association. 404 * 405 * Section: 5.1 Normal Establishment of an Association, C 406 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 407 * timer and leave COOKIE-WAIT state. "A" shall then send the State 408 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 409 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 410 * 411 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 412 * DATA chunks, but it MUST be the first chunk in the packet and 413 * until the COOKIE ACK is returned the sender MUST NOT send any 414 * other packets to the peer. 415 * 416 * Verification Tag: 3.3.3 417 * If the value of the Initiate Tag in a received INIT ACK chunk is 418 * found to be 0, the receiver MUST treat it as an error and close the 419 * association by transmitting an ABORT. 420 * 421 * Inputs 422 * (endpoint, asoc, chunk) 423 * 424 * Outputs 425 * (asoc, reply_msg, msg_up, timers, counters) 426 * 427 * The return value is the disposition of the chunk. 428 */ 429 sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, 430 const struct sctp_association *asoc, 431 const sctp_subtype_t type, 432 void *arg, 433 sctp_cmd_seq_t *commands) 434 { 435 struct sctp_chunk *chunk = arg; 436 sctp_init_chunk_t *initchunk; 437 __u32 init_tag; 438 struct sctp_chunk *err_chunk; 439 struct sctp_packet *packet; 440 sctp_disposition_t ret; 441 442 if (!sctp_vtag_verify(chunk, asoc)) 443 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 444 445 /* Make sure that the INIT-ACK chunk has a valid length */ 446 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 447 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 448 commands); 449 /* 6.10 Bundling 450 * An endpoint MUST NOT bundle INIT, INIT ACK or 451 * SHUTDOWN COMPLETE with any other chunks. 452 */ 453 if (!chunk->singleton) 454 return SCTP_DISPOSITION_VIOLATION; 455 456 /* Grab the INIT header. */ 457 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 458 459 init_tag = ntohl(chunk->subh.init_hdr->init_tag); 460 461 /* Verification Tag: 3.3.3 462 * If the value of the Initiate Tag in a received INIT ACK 463 * chunk is found to be 0, the receiver MUST treat it as an 464 * error and close the association by transmitting an ABORT. 465 */ 466 if (!init_tag) { 467 struct sctp_chunk *reply = sctp_make_abort(asoc, chunk, 0); 468 if (!reply) 469 goto nomem; 470 471 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 472 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 473 SCTP_STATE(SCTP_STATE_CLOSED)); 474 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 475 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 476 return SCTP_DISPOSITION_DELETE_TCB; 477 } 478 479 /* Verify the INIT chunk before processing it. */ 480 err_chunk = NULL; 481 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 482 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 483 &err_chunk)) { 484 485 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 486 487 /* This chunk contains fatal error. It is to be discarded. 488 * Send an ABORT, with causes if there is any. 489 */ 490 if (err_chunk) { 491 packet = sctp_abort_pkt_new(ep, asoc, arg, 492 (__u8 *)(err_chunk->chunk_hdr) + 493 sizeof(sctp_chunkhdr_t), 494 ntohs(err_chunk->chunk_hdr->length) - 495 sizeof(sctp_chunkhdr_t)); 496 497 sctp_chunk_free(err_chunk); 498 499 if (packet) { 500 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 501 SCTP_PACKET(packet)); 502 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 503 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 504 SCTP_STATE(SCTP_STATE_CLOSED)); 505 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, 506 SCTP_NULL()); 507 return SCTP_DISPOSITION_CONSUME; 508 } else { 509 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 510 SCTP_STATE(SCTP_STATE_CLOSED)); 511 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, 512 SCTP_NULL()); 513 return SCTP_DISPOSITION_NOMEM; 514 } 515 } else { 516 ret = sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 517 commands); 518 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 519 SCTP_STATE(SCTP_STATE_CLOSED)); 520 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, 521 SCTP_NULL()); 522 return ret; 523 } 524 } 525 526 /* Tag the variable length parameters. Note that we never 527 * convert the parameters in an INIT chunk. 528 */ 529 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 530 531 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 532 533 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 534 SCTP_PEER_INIT(initchunk)); 535 536 /* Reset init error count upon receipt of INIT-ACK. */ 537 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 538 539 /* 5.1 C) "A" shall stop the T1-init timer and leave 540 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 541 * timer, and enter the COOKIE-ECHOED state. 542 */ 543 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 544 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 545 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 546 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 547 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 548 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 549 550 /* 5.1 C) "A" shall then send the State Cookie received in the 551 * INIT ACK chunk in a COOKIE ECHO chunk, ... 552 */ 553 /* If there is any errors to report, send the ERROR chunk generated 554 * for unknown parameters as well. 555 */ 556 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 557 SCTP_CHUNK(err_chunk)); 558 559 return SCTP_DISPOSITION_CONSUME; 560 561 nomem: 562 return SCTP_DISPOSITION_NOMEM; 563 } 564 565 /* 566 * Respond to a normal COOKIE ECHO chunk. 567 * We are the side that is being asked for an association. 568 * 569 * Section: 5.1 Normal Establishment of an Association, D 570 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 571 * with a COOKIE ACK chunk after building a TCB and moving to 572 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 573 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 574 * chunk MUST be the first chunk in the packet. 575 * 576 * IMPLEMENTATION NOTE: An implementation may choose to send the 577 * Communication Up notification to the SCTP user upon reception 578 * of a valid COOKIE ECHO chunk. 579 * 580 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 581 * D) Rules for packet carrying a COOKIE ECHO 582 * 583 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 584 * Initial Tag received in the INIT ACK. 585 * 586 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 587 * 588 * Inputs 589 * (endpoint, asoc, chunk) 590 * 591 * Outputs 592 * (asoc, reply_msg, msg_up, timers, counters) 593 * 594 * The return value is the disposition of the chunk. 595 */ 596 sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, 597 const struct sctp_association *asoc, 598 const sctp_subtype_t type, void *arg, 599 sctp_cmd_seq_t *commands) 600 { 601 struct sctp_chunk *chunk = arg; 602 struct sctp_association *new_asoc; 603 sctp_init_chunk_t *peer_init; 604 struct sctp_chunk *repl; 605 struct sctp_ulpevent *ev; 606 int error = 0; 607 struct sctp_chunk *err_chk_p; 608 609 /* If the packet is an OOTB packet which is temporarily on the 610 * control endpoint, respond with an ABORT. 611 */ 612 if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) 613 return sctp_sf_ootb(ep, asoc, type, arg, commands); 614 615 /* Make sure that the COOKIE_ECHO chunk has a valid length. 616 * In this case, we check that we have enough for at least a 617 * chunk header. More detailed verification is done 618 * in sctp_unpack_cookie(). 619 */ 620 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 621 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 622 623 /* "Decode" the chunk. We have no optional parameters so we 624 * are in good shape. 625 */ 626 chunk->subh.cookie_hdr = 627 (struct sctp_signed_cookie *)chunk->skb->data; 628 skb_pull(chunk->skb, 629 ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); 630 631 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 632 * "Z" will reply with a COOKIE ACK chunk after building a TCB 633 * and moving to the ESTABLISHED state. 634 */ 635 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 636 &err_chk_p); 637 638 /* FIXME: 639 * If the re-build failed, what is the proper error path 640 * from here? 641 * 642 * [We should abort the association. --piggy] 643 */ 644 if (!new_asoc) { 645 /* FIXME: Several errors are possible. A bad cookie should 646 * be silently discarded, but think about logging it too. 647 */ 648 switch (error) { 649 case -SCTP_IERROR_NOMEM: 650 goto nomem; 651 652 case -SCTP_IERROR_STALE_COOKIE: 653 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 654 err_chk_p); 655 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 656 657 case -SCTP_IERROR_BAD_SIG: 658 default: 659 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 660 }; 661 } 662 663 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 664 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 665 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 666 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 667 SCTP_INC_STATS(SCTP_MIB_PASSIVEESTABS); 668 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 669 670 if (new_asoc->autoclose) 671 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 672 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 673 674 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 675 676 /* Re-build the bind address for the association is done in 677 * the sctp_unpack_cookie() already. 678 */ 679 /* This is a brand-new association, so these are not yet side 680 * effects--it is safe to run them here. 681 */ 682 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 683 684 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 685 &chunk->subh.cookie_hdr->c.peer_addr, 686 peer_init, GFP_ATOMIC)) 687 goto nomem_init; 688 689 repl = sctp_make_cookie_ack(new_asoc, chunk); 690 if (!repl) 691 goto nomem_repl; 692 693 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 694 695 /* RFC 2960 5.1 Normal Establishment of an Association 696 * 697 * D) IMPLEMENTATION NOTE: An implementation may choose to 698 * send the Communication Up notification to the SCTP user 699 * upon reception of a valid COOKIE ECHO chunk. 700 */ 701 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 702 new_asoc->c.sinit_num_ostreams, 703 new_asoc->c.sinit_max_instreams, 704 GFP_ATOMIC); 705 if (!ev) 706 goto nomem_ev; 707 708 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 709 710 /* Sockets API Draft Section 5.3.1.6 711 * When a peer sends a Adaption Layer Indication parameter , SCTP 712 * delivers this notification to inform the application that of the 713 * peers requested adaption layer. 714 */ 715 if (new_asoc->peer.adaption_ind) { 716 ev = sctp_ulpevent_make_adaption_indication(new_asoc, 717 GFP_ATOMIC); 718 if (!ev) 719 goto nomem_ev; 720 721 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 722 SCTP_ULPEVENT(ev)); 723 } 724 725 return SCTP_DISPOSITION_CONSUME; 726 727 nomem_ev: 728 sctp_chunk_free(repl); 729 nomem_repl: 730 nomem_init: 731 sctp_association_free(new_asoc); 732 nomem: 733 return SCTP_DISPOSITION_NOMEM; 734 } 735 736 /* 737 * Respond to a normal COOKIE ACK chunk. 738 * We are the side that is being asked for an association. 739 * 740 * RFC 2960 5.1 Normal Establishment of an Association 741 * 742 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 743 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 744 * timer. It may also notify its ULP about the successful 745 * establishment of the association with a Communication Up 746 * notification (see Section 10). 747 * 748 * Verification Tag: 749 * Inputs 750 * (endpoint, asoc, chunk) 751 * 752 * Outputs 753 * (asoc, reply_msg, msg_up, timers, counters) 754 * 755 * The return value is the disposition of the chunk. 756 */ 757 sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, 758 const struct sctp_association *asoc, 759 const sctp_subtype_t type, void *arg, 760 sctp_cmd_seq_t *commands) 761 { 762 struct sctp_chunk *chunk = arg; 763 struct sctp_ulpevent *ev; 764 765 if (!sctp_vtag_verify(chunk, asoc)) 766 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 767 768 /* Verify that the chunk length for the COOKIE-ACK is OK. 769 * If we don't do this, any bundled chunks may be junked. 770 */ 771 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 772 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 773 commands); 774 775 /* Reset init error count upon receipt of COOKIE-ACK, 776 * to avoid problems with the managemement of this 777 * counter in stale cookie situations when a transition back 778 * from the COOKIE-ECHOED state to the COOKIE-WAIT 779 * state is performed. 780 */ 781 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 782 783 /* RFC 2960 5.1 Normal Establishment of an Association 784 * 785 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 786 * from the COOKIE-ECHOED state to the ESTABLISHED state, 787 * stopping the T1-cookie timer. 788 */ 789 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 790 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 791 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 792 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 793 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 794 SCTP_INC_STATS(SCTP_MIB_ACTIVEESTABS); 795 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 796 if (asoc->autoclose) 797 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 798 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 799 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 800 801 /* It may also notify its ULP about the successful 802 * establishment of the association with a Communication Up 803 * notification (see Section 10). 804 */ 805 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 806 0, asoc->c.sinit_num_ostreams, 807 asoc->c.sinit_max_instreams, 808 GFP_ATOMIC); 809 810 if (!ev) 811 goto nomem; 812 813 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 814 815 /* Sockets API Draft Section 5.3.1.6 816 * When a peer sends a Adaption Layer Indication parameter , SCTP 817 * delivers this notification to inform the application that of the 818 * peers requested adaption layer. 819 */ 820 if (asoc->peer.adaption_ind) { 821 ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC); 822 if (!ev) 823 goto nomem; 824 825 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 826 SCTP_ULPEVENT(ev)); 827 } 828 829 return SCTP_DISPOSITION_CONSUME; 830 nomem: 831 return SCTP_DISPOSITION_NOMEM; 832 } 833 834 /* Generate and sendout a heartbeat packet. */ 835 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 836 const struct sctp_association *asoc, 837 const sctp_subtype_t type, 838 void *arg, 839 sctp_cmd_seq_t *commands) 840 { 841 struct sctp_transport *transport = (struct sctp_transport *) arg; 842 struct sctp_chunk *reply; 843 sctp_sender_hb_info_t hbinfo; 844 size_t paylen = 0; 845 846 hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; 847 hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); 848 hbinfo.daddr = transport->ipaddr; 849 hbinfo.sent_at = jiffies; 850 851 /* Send a heartbeat to our peer. */ 852 paylen = sizeof(sctp_sender_hb_info_t); 853 reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); 854 if (!reply) 855 return SCTP_DISPOSITION_NOMEM; 856 857 /* Set rto_pending indicating that an RTT measurement 858 * is started with this heartbeat chunk. 859 */ 860 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 861 SCTP_TRANSPORT(transport)); 862 863 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 864 return SCTP_DISPOSITION_CONSUME; 865 } 866 867 /* Generate a HEARTBEAT packet on the given transport. */ 868 sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, 869 const struct sctp_association *asoc, 870 const sctp_subtype_t type, 871 void *arg, 872 sctp_cmd_seq_t *commands) 873 { 874 struct sctp_transport *transport = (struct sctp_transport *) arg; 875 876 if (asoc->overall_error_count > asoc->max_retrans) { 877 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 878 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 879 SCTP_U32(SCTP_ERROR_NO_ERROR)); 880 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 881 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 882 return SCTP_DISPOSITION_DELETE_TCB; 883 } 884 885 /* Section 3.3.5. 886 * The Sender-specific Heartbeat Info field should normally include 887 * information about the sender's current time when this HEARTBEAT 888 * chunk is sent and the destination transport address to which this 889 * HEARTBEAT is sent (see Section 8.3). 890 */ 891 892 if (transport->hb_allowed) { 893 if (SCTP_DISPOSITION_NOMEM == 894 sctp_sf_heartbeat(ep, asoc, type, arg, 895 commands)) 896 return SCTP_DISPOSITION_NOMEM; 897 /* Set transport error counter and association error counter 898 * when sending heartbeat. 899 */ 900 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, 901 SCTP_TRANSPORT(transport)); 902 } 903 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 904 SCTP_TRANSPORT(transport)); 905 906 return SCTP_DISPOSITION_CONSUME; 907 } 908 909 /* 910 * Process an heartbeat request. 911 * 912 * Section: 8.3 Path Heartbeat 913 * The receiver of the HEARTBEAT should immediately respond with a 914 * HEARTBEAT ACK that contains the Heartbeat Information field copied 915 * from the received HEARTBEAT chunk. 916 * 917 * Verification Tag: 8.5 Verification Tag [Normal verification] 918 * When receiving an SCTP packet, the endpoint MUST ensure that the 919 * value in the Verification Tag field of the received SCTP packet 920 * matches its own Tag. If the received Verification Tag value does not 921 * match the receiver's own tag value, the receiver shall silently 922 * discard the packet and shall not process it any further except for 923 * those cases listed in Section 8.5.1 below. 924 * 925 * Inputs 926 * (endpoint, asoc, chunk) 927 * 928 * Outputs 929 * (asoc, reply_msg, msg_up, timers, counters) 930 * 931 * The return value is the disposition of the chunk. 932 */ 933 sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, 934 const struct sctp_association *asoc, 935 const sctp_subtype_t type, 936 void *arg, 937 sctp_cmd_seq_t *commands) 938 { 939 struct sctp_chunk *chunk = arg; 940 struct sctp_chunk *reply; 941 size_t paylen = 0; 942 943 if (!sctp_vtag_verify(chunk, asoc)) 944 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 945 946 /* Make sure that the HEARTBEAT chunk has a valid length. */ 947 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 948 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 949 commands); 950 951 /* 8.3 The receiver of the HEARTBEAT should immediately 952 * respond with a HEARTBEAT ACK that contains the Heartbeat 953 * Information field copied from the received HEARTBEAT chunk. 954 */ 955 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 956 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 957 skb_pull(chunk->skb, paylen); 958 959 reply = sctp_make_heartbeat_ack(asoc, chunk, 960 chunk->subh.hb_hdr, paylen); 961 if (!reply) 962 goto nomem; 963 964 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 965 return SCTP_DISPOSITION_CONSUME; 966 967 nomem: 968 return SCTP_DISPOSITION_NOMEM; 969 } 970 971 /* 972 * Process the returning HEARTBEAT ACK. 973 * 974 * Section: 8.3 Path Heartbeat 975 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 976 * should clear the error counter of the destination transport 977 * address to which the HEARTBEAT was sent, and mark the destination 978 * transport address as active if it is not so marked. The endpoint may 979 * optionally report to the upper layer when an inactive destination 980 * address is marked as active due to the reception of the latest 981 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 982 * clear the association overall error count as well (as defined 983 * in section 8.1). 984 * 985 * The receiver of the HEARTBEAT ACK should also perform an RTT 986 * measurement for that destination transport address using the time 987 * value carried in the HEARTBEAT ACK chunk. 988 * 989 * Verification Tag: 8.5 Verification Tag [Normal verification] 990 * 991 * Inputs 992 * (endpoint, asoc, chunk) 993 * 994 * Outputs 995 * (asoc, reply_msg, msg_up, timers, counters) 996 * 997 * The return value is the disposition of the chunk. 998 */ 999 sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, 1000 const struct sctp_association *asoc, 1001 const sctp_subtype_t type, 1002 void *arg, 1003 sctp_cmd_seq_t *commands) 1004 { 1005 struct sctp_chunk *chunk = arg; 1006 union sctp_addr from_addr; 1007 struct sctp_transport *link; 1008 sctp_sender_hb_info_t *hbinfo; 1009 unsigned long max_interval; 1010 1011 if (!sctp_vtag_verify(chunk, asoc)) 1012 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1013 1014 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1015 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1016 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1017 commands); 1018 1019 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1020 from_addr = hbinfo->daddr; 1021 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1022 1023 /* This should never happen, but lets log it if so. */ 1024 if (unlikely(!link)) { 1025 if (from_addr.sa.sa_family == AF_INET6) { 1026 printk(KERN_WARNING 1027 "%s association %p could not find address " 1028 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n", 1029 __FUNCTION__, 1030 asoc, 1031 NIP6(from_addr.v6.sin6_addr)); 1032 } else { 1033 printk(KERN_WARNING 1034 "%s association %p could not find address " 1035 "%u.%u.%u.%u\n", 1036 __FUNCTION__, 1037 asoc, 1038 NIPQUAD(from_addr.v4.sin_addr.s_addr)); 1039 } 1040 return SCTP_DISPOSITION_DISCARD; 1041 } 1042 1043 max_interval = link->hb_interval + link->rto; 1044 1045 /* Check if the timestamp looks valid. */ 1046 if (time_after(hbinfo->sent_at, jiffies) || 1047 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1048 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp" 1049 "received for transport: %p\n", 1050 __FUNCTION__, link); 1051 return SCTP_DISPOSITION_DISCARD; 1052 } 1053 1054 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1055 * the HEARTBEAT should clear the error counter of the 1056 * destination transport address to which the HEARTBEAT was 1057 * sent and mark the destination transport address as active if 1058 * it is not so marked. 1059 */ 1060 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1061 1062 return SCTP_DISPOSITION_CONSUME; 1063 } 1064 1065 /* Helper function to send out an abort for the restart 1066 * condition. 1067 */ 1068 static int sctp_sf_send_restart_abort(union sctp_addr *ssa, 1069 struct sctp_chunk *init, 1070 sctp_cmd_seq_t *commands) 1071 { 1072 int len; 1073 struct sctp_packet *pkt; 1074 union sctp_addr_param *addrparm; 1075 struct sctp_errhdr *errhdr; 1076 struct sctp_endpoint *ep; 1077 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1078 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1079 1080 /* Build the error on the stack. We are way to malloc crazy 1081 * throughout the code today. 1082 */ 1083 errhdr = (struct sctp_errhdr *)buffer; 1084 addrparm = (union sctp_addr_param *)errhdr->variable; 1085 1086 /* Copy into a parm format. */ 1087 len = af->to_addr_param(ssa, addrparm); 1088 len += sizeof(sctp_errhdr_t); 1089 1090 errhdr->cause = SCTP_ERROR_RESTART; 1091 errhdr->length = htons(len); 1092 1093 /* Assign to the control socket. */ 1094 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 1095 1096 /* Association is NULL since this may be a restart attack and we 1097 * want to send back the attacker's vtag. 1098 */ 1099 pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); 1100 1101 if (!pkt) 1102 goto out; 1103 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1104 1105 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1106 1107 /* Discard the rest of the inbound packet. */ 1108 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1109 1110 out: 1111 /* Even if there is no memory, treat as a failure so 1112 * the packet will get dropped. 1113 */ 1114 return 0; 1115 } 1116 1117 /* A restart is occurring, check to make sure no new addresses 1118 * are being added as we may be under a takeover attack. 1119 */ 1120 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1121 const struct sctp_association *asoc, 1122 struct sctp_chunk *init, 1123 sctp_cmd_seq_t *commands) 1124 { 1125 struct sctp_transport *new_addr, *addr; 1126 struct list_head *pos, *pos2; 1127 int found; 1128 1129 /* Implementor's Guide - Sectin 5.2.2 1130 * ... 1131 * Before responding the endpoint MUST check to see if the 1132 * unexpected INIT adds new addresses to the association. If new 1133 * addresses are added to the association, the endpoint MUST respond 1134 * with an ABORT.. 1135 */ 1136 1137 /* Search through all current addresses and make sure 1138 * we aren't adding any new ones. 1139 */ 1140 new_addr = NULL; 1141 found = 0; 1142 1143 list_for_each(pos, &new_asoc->peer.transport_addr_list) { 1144 new_addr = list_entry(pos, struct sctp_transport, transports); 1145 found = 0; 1146 list_for_each(pos2, &asoc->peer.transport_addr_list) { 1147 addr = list_entry(pos2, struct sctp_transport, 1148 transports); 1149 if (sctp_cmp_addr_exact(&new_addr->ipaddr, 1150 &addr->ipaddr)) { 1151 found = 1; 1152 break; 1153 } 1154 } 1155 if (!found) 1156 break; 1157 } 1158 1159 /* If a new address was added, ABORT the sender. */ 1160 if (!found && new_addr) { 1161 sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); 1162 } 1163 1164 /* Return success if all addresses were found. */ 1165 return found; 1166 } 1167 1168 /* Populate the verification/tie tags based on overlapping INIT 1169 * scenario. 1170 * 1171 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1172 */ 1173 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1174 const struct sctp_association *asoc) 1175 { 1176 switch (asoc->state) { 1177 1178 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1179 1180 case SCTP_STATE_COOKIE_WAIT: 1181 new_asoc->c.my_vtag = asoc->c.my_vtag; 1182 new_asoc->c.my_ttag = asoc->c.my_vtag; 1183 new_asoc->c.peer_ttag = 0; 1184 break; 1185 1186 case SCTP_STATE_COOKIE_ECHOED: 1187 new_asoc->c.my_vtag = asoc->c.my_vtag; 1188 new_asoc->c.my_ttag = asoc->c.my_vtag; 1189 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1190 break; 1191 1192 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1193 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1194 */ 1195 default: 1196 new_asoc->c.my_ttag = asoc->c.my_vtag; 1197 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1198 break; 1199 }; 1200 1201 /* Other parameters for the endpoint SHOULD be copied from the 1202 * existing parameters of the association (e.g. number of 1203 * outbound streams) into the INIT ACK and cookie. 1204 */ 1205 new_asoc->rwnd = asoc->rwnd; 1206 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1207 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1208 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1209 } 1210 1211 /* 1212 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1213 * handling action. 1214 * 1215 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1216 * 1217 * Returns value representing action to be taken. These action values 1218 * correspond to Action/Description values in RFC 2960, Table 2. 1219 */ 1220 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1221 const struct sctp_association *asoc) 1222 { 1223 /* In this case, the peer may have restarted. */ 1224 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1225 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1226 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1227 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1228 return 'A'; 1229 1230 /* Collision case B. */ 1231 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1232 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1233 (0 == asoc->c.peer_vtag))) { 1234 return 'B'; 1235 } 1236 1237 /* Collision case D. */ 1238 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1239 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1240 return 'D'; 1241 1242 /* Collision case C. */ 1243 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1244 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1245 (0 == new_asoc->c.my_ttag) && 1246 (0 == new_asoc->c.peer_ttag)) 1247 return 'C'; 1248 1249 /* No match to any of the special cases; discard this packet. */ 1250 return 'E'; 1251 } 1252 1253 /* Common helper routine for both duplicate and simulataneous INIT 1254 * chunk handling. 1255 */ 1256 static sctp_disposition_t sctp_sf_do_unexpected_init( 1257 const struct sctp_endpoint *ep, 1258 const struct sctp_association *asoc, 1259 const sctp_subtype_t type, 1260 void *arg, sctp_cmd_seq_t *commands) 1261 { 1262 sctp_disposition_t retval; 1263 struct sctp_chunk *chunk = arg; 1264 struct sctp_chunk *repl; 1265 struct sctp_association *new_asoc; 1266 struct sctp_chunk *err_chunk; 1267 struct sctp_packet *packet; 1268 sctp_unrecognized_param_t *unk_param; 1269 int len; 1270 1271 /* 6.10 Bundling 1272 * An endpoint MUST NOT bundle INIT, INIT ACK or 1273 * SHUTDOWN COMPLETE with any other chunks. 1274 * 1275 * IG Section 2.11.2 1276 * Furthermore, we require that the receiver of an INIT chunk MUST 1277 * enforce these rules by silently discarding an arriving packet 1278 * with an INIT chunk that is bundled with other chunks. 1279 */ 1280 if (!chunk->singleton) 1281 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1282 1283 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1284 * Tag. 1285 */ 1286 if (chunk->sctp_hdr->vtag != 0) 1287 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 1288 1289 /* Make sure that the INIT chunk has a valid length. 1290 * In this case, we generate a protocol violation since we have 1291 * an association established. 1292 */ 1293 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1294 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1295 commands); 1296 /* Grab the INIT header. */ 1297 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1298 1299 /* Tag the variable length parameters. */ 1300 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1301 1302 /* Verify the INIT chunk before processing it. */ 1303 err_chunk = NULL; 1304 if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, 1305 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1306 &err_chunk)) { 1307 /* This chunk contains fatal error. It is to be discarded. 1308 * Send an ABORT, with causes if there is any. 1309 */ 1310 if (err_chunk) { 1311 packet = sctp_abort_pkt_new(ep, asoc, arg, 1312 (__u8 *)(err_chunk->chunk_hdr) + 1313 sizeof(sctp_chunkhdr_t), 1314 ntohs(err_chunk->chunk_hdr->length) - 1315 sizeof(sctp_chunkhdr_t)); 1316 1317 if (packet) { 1318 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1319 SCTP_PACKET(packet)); 1320 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1321 retval = SCTP_DISPOSITION_CONSUME; 1322 } else { 1323 retval = SCTP_DISPOSITION_NOMEM; 1324 } 1325 goto cleanup; 1326 } else { 1327 return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, 1328 commands); 1329 } 1330 } 1331 1332 /* 1333 * Other parameters for the endpoint SHOULD be copied from the 1334 * existing parameters of the association (e.g. number of 1335 * outbound streams) into the INIT ACK and cookie. 1336 * FIXME: We are copying parameters from the endpoint not the 1337 * association. 1338 */ 1339 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1340 if (!new_asoc) 1341 goto nomem; 1342 1343 /* In the outbound INIT ACK the endpoint MUST copy its current 1344 * Verification Tag and Peers Verification tag into a reserved 1345 * place (local tie-tag and per tie-tag) within the state cookie. 1346 */ 1347 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1348 sctp_source(chunk), 1349 (sctp_init_chunk_t *)chunk->chunk_hdr, 1350 GFP_ATOMIC)) { 1351 retval = SCTP_DISPOSITION_NOMEM; 1352 goto nomem_init; 1353 } 1354 1355 /* Make sure no new addresses are being added during the 1356 * restart. Do not do this check for COOKIE-WAIT state, 1357 * since there are no peer addresses to check against. 1358 * Upon return an ABORT will have been sent if needed. 1359 */ 1360 if (!sctp_state(asoc, COOKIE_WAIT)) { 1361 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1362 commands)) { 1363 retval = SCTP_DISPOSITION_CONSUME; 1364 goto cleanup_asoc; 1365 } 1366 } 1367 1368 sctp_tietags_populate(new_asoc, asoc); 1369 1370 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1371 1372 /* If there are errors need to be reported for unknown parameters, 1373 * make sure to reserve enough room in the INIT ACK for them. 1374 */ 1375 len = 0; 1376 if (err_chunk) { 1377 len = ntohs(err_chunk->chunk_hdr->length) - 1378 sizeof(sctp_chunkhdr_t); 1379 } 1380 1381 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) 1382 goto nomem; 1383 1384 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1385 if (!repl) 1386 goto nomem; 1387 1388 /* If there are errors need to be reported for unknown parameters, 1389 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1390 * parameter. 1391 */ 1392 if (err_chunk) { 1393 /* Get the "Unrecognized parameter" parameter(s) out of the 1394 * ERROR chunk generated by sctp_verify_init(). Since the 1395 * error cause code for "unknown parameter" and the 1396 * "Unrecognized parameter" type is the same, we can 1397 * construct the parameters in INIT ACK by copying the 1398 * ERROR causes over. 1399 */ 1400 unk_param = (sctp_unrecognized_param_t *) 1401 ((__u8 *)(err_chunk->chunk_hdr) + 1402 sizeof(sctp_chunkhdr_t)); 1403 /* Replace the cause code with the "Unrecognized parameter" 1404 * parameter type. 1405 */ 1406 sctp_addto_chunk(repl, len, unk_param); 1407 } 1408 1409 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1410 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1411 1412 /* 1413 * Note: After sending out INIT ACK with the State Cookie parameter, 1414 * "Z" MUST NOT allocate any resources for this new association. 1415 * Otherwise, "Z" will be vulnerable to resource attacks. 1416 */ 1417 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1418 retval = SCTP_DISPOSITION_CONSUME; 1419 1420 cleanup: 1421 if (err_chunk) 1422 sctp_chunk_free(err_chunk); 1423 return retval; 1424 nomem: 1425 retval = SCTP_DISPOSITION_NOMEM; 1426 goto cleanup; 1427 nomem_init: 1428 cleanup_asoc: 1429 sctp_association_free(new_asoc); 1430 goto cleanup; 1431 } 1432 1433 /* 1434 * Handle simultanous INIT. 1435 * This means we started an INIT and then we got an INIT request from 1436 * our peer. 1437 * 1438 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1439 * This usually indicates an initialization collision, i.e., each 1440 * endpoint is attempting, at about the same time, to establish an 1441 * association with the other endpoint. 1442 * 1443 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1444 * endpoint MUST respond with an INIT ACK using the same parameters it 1445 * sent in its original INIT chunk (including its Verification Tag, 1446 * unchanged). These original parameters are combined with those from the 1447 * newly received INIT chunk. The endpoint shall also generate a State 1448 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1449 * INIT to calculate the State Cookie. 1450 * 1451 * After that, the endpoint MUST NOT change its state, the T1-init 1452 * timer shall be left running and the corresponding TCB MUST NOT be 1453 * destroyed. The normal procedures for handling State Cookies when 1454 * a TCB exists will resolve the duplicate INITs to a single association. 1455 * 1456 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1457 * its Tie-Tags with the Tag information of itself and its peer (see 1458 * section 5.2.2 for a description of the Tie-Tags). 1459 * 1460 * Verification Tag: Not explicit, but an INIT can not have a valid 1461 * verification tag, so we skip the check. 1462 * 1463 * Inputs 1464 * (endpoint, asoc, chunk) 1465 * 1466 * Outputs 1467 * (asoc, reply_msg, msg_up, timers, counters) 1468 * 1469 * The return value is the disposition of the chunk. 1470 */ 1471 sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, 1472 const struct sctp_association *asoc, 1473 const sctp_subtype_t type, 1474 void *arg, 1475 sctp_cmd_seq_t *commands) 1476 { 1477 /* Call helper to do the real work for both simulataneous and 1478 * duplicate INIT chunk handling. 1479 */ 1480 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1481 } 1482 1483 /* 1484 * Handle duplicated INIT messages. These are usually delayed 1485 * restransmissions. 1486 * 1487 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1488 * COOKIE-ECHOED and COOKIE-WAIT 1489 * 1490 * Unless otherwise stated, upon reception of an unexpected INIT for 1491 * this association, the endpoint shall generate an INIT ACK with a 1492 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1493 * current Verification Tag and peer's Verification Tag into a reserved 1494 * place within the state cookie. We shall refer to these locations as 1495 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1496 * containing this INIT ACK MUST carry a Verification Tag value equal to 1497 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1498 * MUST contain a new Initiation Tag (randomly generated see Section 1499 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1500 * existing parameters of the association (e.g. number of outbound 1501 * streams) into the INIT ACK and cookie. 1502 * 1503 * After sending out the INIT ACK, the endpoint shall take no further 1504 * actions, i.e., the existing association, including its current state, 1505 * and the corresponding TCB MUST NOT be changed. 1506 * 1507 * Note: Only when a TCB exists and the association is not in a COOKIE- 1508 * WAIT state are the Tie-Tags populated. For a normal association INIT 1509 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1510 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1511 * State Cookie are populated as specified in section 5.2.1. 1512 * 1513 * Verification Tag: Not specified, but an INIT has no way of knowing 1514 * what the verification tag could be, so we ignore it. 1515 * 1516 * Inputs 1517 * (endpoint, asoc, chunk) 1518 * 1519 * Outputs 1520 * (asoc, reply_msg, msg_up, timers, counters) 1521 * 1522 * The return value is the disposition of the chunk. 1523 */ 1524 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, 1525 const struct sctp_association *asoc, 1526 const sctp_subtype_t type, 1527 void *arg, 1528 sctp_cmd_seq_t *commands) 1529 { 1530 /* Call helper to do the real work for both simulataneous and 1531 * duplicate INIT chunk handling. 1532 */ 1533 return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); 1534 } 1535 1536 1537 1538 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1539 * 1540 * Section 5.2.4 1541 * A) In this case, the peer may have restarted. 1542 */ 1543 static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, 1544 const struct sctp_association *asoc, 1545 struct sctp_chunk *chunk, 1546 sctp_cmd_seq_t *commands, 1547 struct sctp_association *new_asoc) 1548 { 1549 sctp_init_chunk_t *peer_init; 1550 struct sctp_ulpevent *ev; 1551 struct sctp_chunk *repl; 1552 struct sctp_chunk *err; 1553 sctp_disposition_t disposition; 1554 1555 /* new_asoc is a brand-new association, so these are not yet 1556 * side effects--it is safe to run them here. 1557 */ 1558 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1559 1560 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1561 sctp_source(chunk), peer_init, 1562 GFP_ATOMIC)) 1563 goto nomem; 1564 1565 /* Make sure no new addresses are being added during the 1566 * restart. Though this is a pretty complicated attack 1567 * since you'd have to get inside the cookie. 1568 */ 1569 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1570 return SCTP_DISPOSITION_CONSUME; 1571 } 1572 1573 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1574 * the peer has restarted (Action A), it MUST NOT setup a new 1575 * association but instead resend the SHUTDOWN ACK and send an ERROR 1576 * chunk with a "Cookie Received while Shutting Down" error cause to 1577 * its peer. 1578 */ 1579 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1580 disposition = sctp_sf_do_9_2_reshutack(ep, asoc, 1581 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1582 chunk, commands); 1583 if (SCTP_DISPOSITION_NOMEM == disposition) 1584 goto nomem; 1585 1586 err = sctp_make_op_error(asoc, chunk, 1587 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1588 NULL, 0); 1589 if (err) 1590 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1591 SCTP_CHUNK(err)); 1592 1593 return SCTP_DISPOSITION_CONSUME; 1594 } 1595 1596 /* For now, fail any unsent/unacked data. Consider the optional 1597 * choice of resending of this data. 1598 */ 1599 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1600 1601 /* Update the content of current association. */ 1602 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1603 1604 repl = sctp_make_cookie_ack(new_asoc, chunk); 1605 if (!repl) 1606 goto nomem; 1607 1608 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1609 1610 /* Report association restart to upper layer. */ 1611 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1612 new_asoc->c.sinit_num_ostreams, 1613 new_asoc->c.sinit_max_instreams, 1614 GFP_ATOMIC); 1615 if (!ev) 1616 goto nomem_ev; 1617 1618 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1619 return SCTP_DISPOSITION_CONSUME; 1620 1621 nomem_ev: 1622 sctp_chunk_free(repl); 1623 nomem: 1624 return SCTP_DISPOSITION_NOMEM; 1625 } 1626 1627 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1628 * 1629 * Section 5.2.4 1630 * B) In this case, both sides may be attempting to start an association 1631 * at about the same time but the peer endpoint started its INIT 1632 * after responding to the local endpoint's INIT 1633 */ 1634 /* This case represents an initialization collision. */ 1635 static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, 1636 const struct sctp_association *asoc, 1637 struct sctp_chunk *chunk, 1638 sctp_cmd_seq_t *commands, 1639 struct sctp_association *new_asoc) 1640 { 1641 sctp_init_chunk_t *peer_init; 1642 struct sctp_ulpevent *ev; 1643 struct sctp_chunk *repl; 1644 1645 /* new_asoc is a brand-new association, so these are not yet 1646 * side effects--it is safe to run them here. 1647 */ 1648 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1649 if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, 1650 sctp_source(chunk), peer_init, 1651 GFP_ATOMIC)) 1652 goto nomem; 1653 1654 /* Update the content of current association. */ 1655 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1656 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1657 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1658 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1659 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1660 1661 repl = sctp_make_cookie_ack(new_asoc, chunk); 1662 if (!repl) 1663 goto nomem; 1664 1665 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1666 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1667 1668 /* RFC 2960 5.1 Normal Establishment of an Association 1669 * 1670 * D) IMPLEMENTATION NOTE: An implementation may choose to 1671 * send the Communication Up notification to the SCTP user 1672 * upon reception of a valid COOKIE ECHO chunk. 1673 */ 1674 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0, 1675 new_asoc->c.sinit_num_ostreams, 1676 new_asoc->c.sinit_max_instreams, 1677 GFP_ATOMIC); 1678 if (!ev) 1679 goto nomem_ev; 1680 1681 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1682 1683 /* Sockets API Draft Section 5.3.1.6 1684 * When a peer sends a Adaption Layer Indication parameter , SCTP 1685 * delivers this notification to inform the application that of the 1686 * peers requested adaption layer. 1687 */ 1688 if (asoc->peer.adaption_ind) { 1689 ev = sctp_ulpevent_make_adaption_indication(asoc, GFP_ATOMIC); 1690 if (!ev) 1691 goto nomem_ev; 1692 1693 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1694 SCTP_ULPEVENT(ev)); 1695 } 1696 1697 return SCTP_DISPOSITION_CONSUME; 1698 1699 nomem_ev: 1700 sctp_chunk_free(repl); 1701 nomem: 1702 return SCTP_DISPOSITION_NOMEM; 1703 } 1704 1705 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1706 * 1707 * Section 5.2.4 1708 * C) In this case, the local endpoint's cookie has arrived late. 1709 * Before it arrived, the local endpoint sent an INIT and received an 1710 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1711 * but a new tag of its own. 1712 */ 1713 /* This case represents an initialization collision. */ 1714 static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, 1715 const struct sctp_association *asoc, 1716 struct sctp_chunk *chunk, 1717 sctp_cmd_seq_t *commands, 1718 struct sctp_association *new_asoc) 1719 { 1720 /* The cookie should be silently discarded. 1721 * The endpoint SHOULD NOT change states and should leave 1722 * any timers running. 1723 */ 1724 return SCTP_DISPOSITION_DISCARD; 1725 } 1726 1727 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1728 * 1729 * Section 5.2.4 1730 * 1731 * D) When both local and remote tags match the endpoint should always 1732 * enter the ESTABLISHED state, if it has not already done so. 1733 */ 1734 /* This case represents an initialization collision. */ 1735 static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, 1736 const struct sctp_association *asoc, 1737 struct sctp_chunk *chunk, 1738 sctp_cmd_seq_t *commands, 1739 struct sctp_association *new_asoc) 1740 { 1741 struct sctp_ulpevent *ev = NULL; 1742 struct sctp_chunk *repl; 1743 1744 /* Clarification from Implementor's Guide: 1745 * D) When both local and remote tags match the endpoint should 1746 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1747 * It should stop any cookie timer that may be running and send 1748 * a COOKIE ACK. 1749 */ 1750 1751 /* Don't accidentally move back into established state. */ 1752 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1753 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1754 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1755 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1756 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1757 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 1758 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1759 SCTP_NULL()); 1760 1761 /* RFC 2960 5.1 Normal Establishment of an Association 1762 * 1763 * D) IMPLEMENTATION NOTE: An implementation may choose 1764 * to send the Communication Up notification to the 1765 * SCTP user upon reception of a valid COOKIE 1766 * ECHO chunk. 1767 */ 1768 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, 1769 SCTP_COMM_UP, 0, 1770 new_asoc->c.sinit_num_ostreams, 1771 new_asoc->c.sinit_max_instreams, 1772 GFP_ATOMIC); 1773 if (!ev) 1774 goto nomem; 1775 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1776 SCTP_ULPEVENT(ev)); 1777 1778 /* Sockets API Draft Section 5.3.1.6 1779 * When a peer sends a Adaption Layer Indication parameter, 1780 * SCTP delivers this notification to inform the application 1781 * that of the peers requested adaption layer. 1782 */ 1783 if (new_asoc->peer.adaption_ind) { 1784 ev = sctp_ulpevent_make_adaption_indication(new_asoc, 1785 GFP_ATOMIC); 1786 if (!ev) 1787 goto nomem; 1788 1789 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1790 SCTP_ULPEVENT(ev)); 1791 } 1792 } 1793 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1794 1795 repl = sctp_make_cookie_ack(new_asoc, chunk); 1796 if (!repl) 1797 goto nomem; 1798 1799 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1800 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); 1801 1802 return SCTP_DISPOSITION_CONSUME; 1803 1804 nomem: 1805 if (ev) 1806 sctp_ulpevent_free(ev); 1807 return SCTP_DISPOSITION_NOMEM; 1808 } 1809 1810 /* 1811 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1812 * chunk was retransmitted and then delayed in the network. 1813 * 1814 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1815 * 1816 * Verification Tag: None. Do cookie validation. 1817 * 1818 * Inputs 1819 * (endpoint, asoc, chunk) 1820 * 1821 * Outputs 1822 * (asoc, reply_msg, msg_up, timers, counters) 1823 * 1824 * The return value is the disposition of the chunk. 1825 */ 1826 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, 1827 const struct sctp_association *asoc, 1828 const sctp_subtype_t type, 1829 void *arg, 1830 sctp_cmd_seq_t *commands) 1831 { 1832 sctp_disposition_t retval; 1833 struct sctp_chunk *chunk = arg; 1834 struct sctp_association *new_asoc; 1835 int error = 0; 1836 char action; 1837 struct sctp_chunk *err_chk_p; 1838 1839 /* Make sure that the chunk has a valid length from the protocol 1840 * perspective. In this case check to make sure we have at least 1841 * enough for the chunk header. Cookie length verification is 1842 * done later. 1843 */ 1844 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 1845 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 1846 commands); 1847 1848 /* "Decode" the chunk. We have no optional parameters so we 1849 * are in good shape. 1850 */ 1851 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 1852 skb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 1853 sizeof(sctp_chunkhdr_t)); 1854 1855 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 1856 * of a duplicate COOKIE ECHO match the Verification Tags of the 1857 * current association, consider the State Cookie valid even if 1858 * the lifespan is exceeded. 1859 */ 1860 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 1861 &err_chk_p); 1862 1863 /* FIXME: 1864 * If the re-build failed, what is the proper error path 1865 * from here? 1866 * 1867 * [We should abort the association. --piggy] 1868 */ 1869 if (!new_asoc) { 1870 /* FIXME: Several errors are possible. A bad cookie should 1871 * be silently discarded, but think about logging it too. 1872 */ 1873 switch (error) { 1874 case -SCTP_IERROR_NOMEM: 1875 goto nomem; 1876 1877 case -SCTP_IERROR_STALE_COOKIE: 1878 sctp_send_stale_cookie_err(ep, asoc, chunk, commands, 1879 err_chk_p); 1880 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1881 case -SCTP_IERROR_BAD_SIG: 1882 default: 1883 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1884 }; 1885 } 1886 1887 /* Compare the tie_tag in cookie with the verification tag of 1888 * current association. 1889 */ 1890 action = sctp_tietags_compare(new_asoc, asoc); 1891 1892 switch (action) { 1893 case 'A': /* Association restart. */ 1894 retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, 1895 new_asoc); 1896 break; 1897 1898 case 'B': /* Collision case B. */ 1899 retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, 1900 new_asoc); 1901 break; 1902 1903 case 'C': /* Collision case C. */ 1904 retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, 1905 new_asoc); 1906 break; 1907 1908 case 'D': /* Collision case D. */ 1909 retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, 1910 new_asoc); 1911 break; 1912 1913 default: /* Discard packet for all others. */ 1914 retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1915 break; 1916 }; 1917 1918 /* Delete the tempory new association. */ 1919 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1920 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1921 1922 return retval; 1923 1924 nomem: 1925 return SCTP_DISPOSITION_NOMEM; 1926 } 1927 1928 /* 1929 * Process an ABORT. (SHUTDOWN-PENDING state) 1930 * 1931 * See sctp_sf_do_9_1_abort(). 1932 */ 1933 sctp_disposition_t sctp_sf_shutdown_pending_abort( 1934 const struct sctp_endpoint *ep, 1935 const struct sctp_association *asoc, 1936 const sctp_subtype_t type, 1937 void *arg, 1938 sctp_cmd_seq_t *commands) 1939 { 1940 struct sctp_chunk *chunk = arg; 1941 1942 if (!sctp_vtag_verify_either(chunk, asoc)) 1943 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1944 1945 /* Make sure that the ABORT chunk has a valid length. 1946 * Since this is an ABORT chunk, we have to discard it 1947 * because of the following text: 1948 * RFC 2960, Section 3.3.7 1949 * If an endpoint receives an ABORT with a format error or for an 1950 * association that doesn't exist, it MUST silently discard it. 1951 * Becasue the length is "invalid", we can't really discard just 1952 * as we do not know its true length. So, to be safe, discard the 1953 * packet. 1954 */ 1955 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 1956 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1957 1958 /* Stop the T5-shutdown guard timer. */ 1959 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1960 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 1961 1962 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 1963 } 1964 1965 /* 1966 * Process an ABORT. (SHUTDOWN-SENT state) 1967 * 1968 * See sctp_sf_do_9_1_abort(). 1969 */ 1970 sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, 1971 const struct sctp_association *asoc, 1972 const sctp_subtype_t type, 1973 void *arg, 1974 sctp_cmd_seq_t *commands) 1975 { 1976 struct sctp_chunk *chunk = arg; 1977 1978 if (!sctp_vtag_verify_either(chunk, asoc)) 1979 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1980 1981 /* Make sure that the ABORT chunk has a valid length. 1982 * Since this is an ABORT chunk, we have to discard it 1983 * because of the following text: 1984 * RFC 2960, Section 3.3.7 1985 * If an endpoint receives an ABORT with a format error or for an 1986 * association that doesn't exist, it MUST silently discard it. 1987 * Becasue the length is "invalid", we can't really discard just 1988 * as we do not know its true length. So, to be safe, discard the 1989 * packet. 1990 */ 1991 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 1992 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 1993 1994 /* Stop the T2-shutdown timer. */ 1995 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1996 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 1997 1998 /* Stop the T5-shutdown guard timer. */ 1999 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2000 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2001 2002 return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); 2003 } 2004 2005 /* 2006 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2007 * 2008 * See sctp_sf_do_9_1_abort(). 2009 */ 2010 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2011 const struct sctp_endpoint *ep, 2012 const struct sctp_association *asoc, 2013 const sctp_subtype_t type, 2014 void *arg, 2015 sctp_cmd_seq_t *commands) 2016 { 2017 /* The same T2 timer, so we should be able to use 2018 * common function with the SHUTDOWN-SENT state. 2019 */ 2020 return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); 2021 } 2022 2023 /* 2024 * Handle an Error received in COOKIE_ECHOED state. 2025 * 2026 * Only handle the error type of stale COOKIE Error, the other errors will 2027 * be ignored. 2028 * 2029 * Inputs 2030 * (endpoint, asoc, chunk) 2031 * 2032 * Outputs 2033 * (asoc, reply_msg, msg_up, timers, counters) 2034 * 2035 * The return value is the disposition of the chunk. 2036 */ 2037 sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, 2038 const struct sctp_association *asoc, 2039 const sctp_subtype_t type, 2040 void *arg, 2041 sctp_cmd_seq_t *commands) 2042 { 2043 struct sctp_chunk *chunk = arg; 2044 sctp_errhdr_t *err; 2045 2046 if (!sctp_vtag_verify(chunk, asoc)) 2047 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2048 2049 /* Make sure that the ERROR chunk has a valid length. 2050 * The parameter walking depends on this as well. 2051 */ 2052 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2053 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2054 commands); 2055 2056 /* Process the error here */ 2057 /* FUTURE FIXME: When PR-SCTP related and other optional 2058 * parms are emitted, this will have to change to handle multiple 2059 * errors. 2060 */ 2061 sctp_walk_errors(err, chunk->chunk_hdr) { 2062 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2063 return sctp_sf_do_5_2_6_stale(ep, asoc, type, 2064 arg, commands); 2065 } 2066 2067 /* It is possible to have malformed error causes, and that 2068 * will cause us to end the walk early. However, since 2069 * we are discarding the packet, there should be no adverse 2070 * affects. 2071 */ 2072 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2073 } 2074 2075 /* 2076 * Handle a Stale COOKIE Error 2077 * 2078 * Section: 5.2.6 Handle Stale COOKIE Error 2079 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2080 * one of the following three alternatives. 2081 * ... 2082 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2083 * Preservative parameter requesting an extension to the lifetime of 2084 * the State Cookie. When calculating the time extension, an 2085 * implementation SHOULD use the RTT information measured based on the 2086 * previous COOKIE ECHO / ERROR exchange, and should add no more 2087 * than 1 second beyond the measured RTT, due to long State Cookie 2088 * lifetimes making the endpoint more subject to a replay attack. 2089 * 2090 * Verification Tag: Not explicit, but safe to ignore. 2091 * 2092 * Inputs 2093 * (endpoint, asoc, chunk) 2094 * 2095 * Outputs 2096 * (asoc, reply_msg, msg_up, timers, counters) 2097 * 2098 * The return value is the disposition of the chunk. 2099 */ 2100 static sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, 2101 const struct sctp_association *asoc, 2102 const sctp_subtype_t type, 2103 void *arg, 2104 sctp_cmd_seq_t *commands) 2105 { 2106 struct sctp_chunk *chunk = arg; 2107 time_t stale; 2108 sctp_cookie_preserve_param_t bht; 2109 sctp_errhdr_t *err; 2110 struct sctp_chunk *reply; 2111 struct sctp_bind_addr *bp; 2112 int attempts = asoc->init_err_counter + 1; 2113 2114 if (attempts >= asoc->max_init_attempts) { 2115 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2116 SCTP_U32(SCTP_ERROR_STALE_COOKIE)); 2117 return SCTP_DISPOSITION_DELETE_TCB; 2118 } 2119 2120 err = (sctp_errhdr_t *)(chunk->skb->data); 2121 2122 /* When calculating the time extension, an implementation 2123 * SHOULD use the RTT information measured based on the 2124 * previous COOKIE ECHO / ERROR exchange, and should add no 2125 * more than 1 second beyond the measured RTT, due to long 2126 * State Cookie lifetimes making the endpoint more subject to 2127 * a replay attack. 2128 * Measure of Staleness's unit is usec. (1/1000000 sec) 2129 * Suggested Cookie Life-span Increment's unit is msec. 2130 * (1/1000 sec) 2131 * In general, if you use the suggested cookie life, the value 2132 * found in the field of measure of staleness should be doubled 2133 * to give ample time to retransmit the new cookie and thus 2134 * yield a higher probability of success on the reattempt. 2135 */ 2136 stale = ntohl(*(suseconds_t *)((u8 *)err + sizeof(sctp_errhdr_t))); 2137 stale = (stale * 2) / 1000; 2138 2139 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2140 bht.param_hdr.length = htons(sizeof(bht)); 2141 bht.lifespan_increment = htonl(stale); 2142 2143 /* Build that new INIT chunk. */ 2144 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2145 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2146 if (!reply) 2147 goto nomem; 2148 2149 sctp_addto_chunk(reply, sizeof(bht), &bht); 2150 2151 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2152 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2153 2154 /* Stop pending T3-rtx and heartbeat timers */ 2155 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2156 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2157 2158 /* Delete non-primary peer ip addresses since we are transitioning 2159 * back to the COOKIE-WAIT state 2160 */ 2161 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2162 2163 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2164 * resend 2165 */ 2166 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, 2167 SCTP_TRANSPORT(asoc->peer.primary_path)); 2168 2169 /* Cast away the const modifier, as we want to just 2170 * rerun it through as a sideffect. 2171 */ 2172 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2173 2174 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2175 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2176 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2177 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2178 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2179 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2180 2181 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2182 2183 return SCTP_DISPOSITION_CONSUME; 2184 2185 nomem: 2186 return SCTP_DISPOSITION_NOMEM; 2187 } 2188 2189 /* 2190 * Process an ABORT. 2191 * 2192 * Section: 9.1 2193 * After checking the Verification Tag, the receiving endpoint shall 2194 * remove the association from its record, and shall report the 2195 * termination to its upper layer. 2196 * 2197 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2198 * B) Rules for packet carrying ABORT: 2199 * 2200 * - The endpoint shall always fill in the Verification Tag field of the 2201 * outbound packet with the destination endpoint's tag value if it 2202 * is known. 2203 * 2204 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2205 * MUST follow the procedure described in Section 8.4. 2206 * 2207 * - The receiver MUST accept the packet if the Verification Tag 2208 * matches either its own tag, OR the tag of its peer. Otherwise, the 2209 * receiver MUST silently discard the packet and take no further 2210 * action. 2211 * 2212 * Inputs 2213 * (endpoint, asoc, chunk) 2214 * 2215 * Outputs 2216 * (asoc, reply_msg, msg_up, timers, counters) 2217 * 2218 * The return value is the disposition of the chunk. 2219 */ 2220 sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, 2221 const struct sctp_association *asoc, 2222 const sctp_subtype_t type, 2223 void *arg, 2224 sctp_cmd_seq_t *commands) 2225 { 2226 struct sctp_chunk *chunk = arg; 2227 unsigned len; 2228 __u16 error = SCTP_ERROR_NO_ERROR; 2229 2230 if (!sctp_vtag_verify_either(chunk, asoc)) 2231 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2232 2233 /* Make sure that the ABORT chunk has a valid length. 2234 * Since this is an ABORT chunk, we have to discard it 2235 * because of the following text: 2236 * RFC 2960, Section 3.3.7 2237 * If an endpoint receives an ABORT with a format error or for an 2238 * association that doesn't exist, it MUST silently discard it. 2239 * Becasue the length is "invalid", we can't really discard just 2240 * as we do not know its true length. So, to be safe, discard the 2241 * packet. 2242 */ 2243 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2244 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2245 2246 /* See if we have an error cause code in the chunk. */ 2247 len = ntohs(chunk->chunk_hdr->length); 2248 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2249 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2250 2251 /* ASSOC_FAILED will DELETE_TCB. */ 2252 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(error)); 2253 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2254 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 2255 2256 return SCTP_DISPOSITION_ABORT; 2257 } 2258 2259 /* 2260 * Process an ABORT. (COOKIE-WAIT state) 2261 * 2262 * See sctp_sf_do_9_1_abort() above. 2263 */ 2264 sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, 2265 const struct sctp_association *asoc, 2266 const sctp_subtype_t type, 2267 void *arg, 2268 sctp_cmd_seq_t *commands) 2269 { 2270 struct sctp_chunk *chunk = arg; 2271 unsigned len; 2272 __u16 error = SCTP_ERROR_NO_ERROR; 2273 2274 if (!sctp_vtag_verify_either(chunk, asoc)) 2275 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2276 2277 /* Make sure that the ABORT chunk has a valid length. 2278 * Since this is an ABORT chunk, we have to discard it 2279 * because of the following text: 2280 * RFC 2960, Section 3.3.7 2281 * If an endpoint receives an ABORT with a format error or for an 2282 * association that doesn't exist, it MUST silently discard it. 2283 * Becasue the length is "invalid", we can't really discard just 2284 * as we do not know its true length. So, to be safe, discard the 2285 * packet. 2286 */ 2287 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2288 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2289 2290 /* See if we have an error cause code in the chunk. */ 2291 len = ntohs(chunk->chunk_hdr->length); 2292 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2293 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2294 2295 return sctp_stop_t1_and_abort(commands, error, asoc, chunk->transport); 2296 } 2297 2298 /* 2299 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2300 */ 2301 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(const struct sctp_endpoint *ep, 2302 const struct sctp_association *asoc, 2303 const sctp_subtype_t type, 2304 void *arg, 2305 sctp_cmd_seq_t *commands) 2306 { 2307 return sctp_stop_t1_and_abort(commands, SCTP_ERROR_NO_ERROR, asoc, 2308 (struct sctp_transport *)arg); 2309 } 2310 2311 /* 2312 * Process an ABORT. (COOKIE-ECHOED state) 2313 */ 2314 sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, 2315 const struct sctp_association *asoc, 2316 const sctp_subtype_t type, 2317 void *arg, 2318 sctp_cmd_seq_t *commands) 2319 { 2320 /* There is a single T1 timer, so we should be able to use 2321 * common function with the COOKIE-WAIT state. 2322 */ 2323 return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); 2324 } 2325 2326 /* 2327 * Stop T1 timer and abort association with "INIT failed". 2328 * 2329 * This is common code called by several sctp_sf_*_abort() functions above. 2330 */ 2331 sctp_disposition_t sctp_stop_t1_and_abort(sctp_cmd_seq_t *commands, 2332 __u16 error, 2333 const struct sctp_association *asoc, 2334 struct sctp_transport *transport) 2335 { 2336 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2337 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2338 SCTP_STATE(SCTP_STATE_CLOSED)); 2339 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 2340 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2341 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2342 /* CMD_INIT_FAILED will DELETE_TCB. */ 2343 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2344 SCTP_U32(error)); 2345 return SCTP_DISPOSITION_ABORT; 2346 } 2347 2348 /* 2349 * sctp_sf_do_9_2_shut 2350 * 2351 * Section: 9.2 2352 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2353 * - enter the SHUTDOWN-RECEIVED state, 2354 * 2355 * - stop accepting new data from its SCTP user 2356 * 2357 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2358 * that all its outstanding DATA chunks have been received by the 2359 * SHUTDOWN sender. 2360 * 2361 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2362 * send a SHUTDOWN in response to a ULP request. And should discard 2363 * subsequent SHUTDOWN chunks. 2364 * 2365 * If there are still outstanding DATA chunks left, the SHUTDOWN 2366 * receiver shall continue to follow normal data transmission 2367 * procedures defined in Section 6 until all outstanding DATA chunks 2368 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2369 * new data from its SCTP user. 2370 * 2371 * Verification Tag: 8.5 Verification Tag [Normal verification] 2372 * 2373 * Inputs 2374 * (endpoint, asoc, chunk) 2375 * 2376 * Outputs 2377 * (asoc, reply_msg, msg_up, timers, counters) 2378 * 2379 * The return value is the disposition of the chunk. 2380 */ 2381 sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, 2382 const struct sctp_association *asoc, 2383 const sctp_subtype_t type, 2384 void *arg, 2385 sctp_cmd_seq_t *commands) 2386 { 2387 struct sctp_chunk *chunk = arg; 2388 sctp_shutdownhdr_t *sdh; 2389 sctp_disposition_t disposition; 2390 struct sctp_ulpevent *ev; 2391 2392 if (!sctp_vtag_verify(chunk, asoc)) 2393 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2394 2395 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2396 if (!sctp_chunk_length_valid(chunk, 2397 sizeof(struct sctp_shutdown_chunk_t))) 2398 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2399 commands); 2400 2401 /* Convert the elaborate header. */ 2402 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2403 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2404 chunk->subh.shutdown_hdr = sdh; 2405 2406 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2407 * - enter the SHUTDOWN-RECEIVED state, 2408 * - stop accepting new data from its SCTP user 2409 * 2410 * [This is implicit in the new state.] 2411 */ 2412 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2413 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2414 disposition = SCTP_DISPOSITION_CONSUME; 2415 2416 if (sctp_outq_is_empty(&asoc->outqueue)) { 2417 disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, 2418 arg, commands); 2419 } 2420 2421 if (SCTP_DISPOSITION_NOMEM == disposition) 2422 goto out; 2423 2424 /* - verify, by checking the Cumulative TSN Ack field of the 2425 * chunk, that all its outstanding DATA chunks have been 2426 * received by the SHUTDOWN sender. 2427 */ 2428 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2429 SCTP_U32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2430 2431 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2432 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2433 * inform the application that it should cease sending data. 2434 */ 2435 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2436 if (!ev) { 2437 disposition = SCTP_DISPOSITION_NOMEM; 2438 goto out; 2439 } 2440 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2441 2442 out: 2443 return disposition; 2444 } 2445 2446 /* RFC 2960 9.2 2447 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2448 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2449 * transport addresses (either in the IP addresses or in the INIT chunk) 2450 * that belong to this association, it should discard the INIT chunk and 2451 * retransmit the SHUTDOWN ACK chunk. 2452 */ 2453 sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, 2454 const struct sctp_association *asoc, 2455 const sctp_subtype_t type, 2456 void *arg, 2457 sctp_cmd_seq_t *commands) 2458 { 2459 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2460 struct sctp_chunk *reply; 2461 2462 /* Since we are not going to really process this INIT, there 2463 * is no point in verifying chunk boundries. Just generate 2464 * the SHUTDOWN ACK. 2465 */ 2466 reply = sctp_make_shutdown_ack(asoc, chunk); 2467 if (NULL == reply) 2468 goto nomem; 2469 2470 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2471 * the T2-SHUTDOWN timer. 2472 */ 2473 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2474 2475 /* and restart the T2-shutdown timer. */ 2476 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2477 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2478 2479 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2480 2481 return SCTP_DISPOSITION_CONSUME; 2482 nomem: 2483 return SCTP_DISPOSITION_NOMEM; 2484 } 2485 2486 /* 2487 * sctp_sf_do_ecn_cwr 2488 * 2489 * Section: Appendix A: Explicit Congestion Notification 2490 * 2491 * CWR: 2492 * 2493 * RFC 2481 details a specific bit for a sender to send in the header of 2494 * its next outbound TCP segment to indicate to its peer that it has 2495 * reduced its congestion window. This is termed the CWR bit. For 2496 * SCTP the same indication is made by including the CWR chunk. 2497 * This chunk contains one data element, i.e. the TSN number that 2498 * was sent in the ECNE chunk. This element represents the lowest 2499 * TSN number in the datagram that was originally marked with the 2500 * CE bit. 2501 * 2502 * Verification Tag: 8.5 Verification Tag [Normal verification] 2503 * Inputs 2504 * (endpoint, asoc, chunk) 2505 * 2506 * Outputs 2507 * (asoc, reply_msg, msg_up, timers, counters) 2508 * 2509 * The return value is the disposition of the chunk. 2510 */ 2511 sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, 2512 const struct sctp_association *asoc, 2513 const sctp_subtype_t type, 2514 void *arg, 2515 sctp_cmd_seq_t *commands) 2516 { 2517 sctp_cwrhdr_t *cwr; 2518 struct sctp_chunk *chunk = arg; 2519 2520 if (!sctp_vtag_verify(chunk, asoc)) 2521 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2522 2523 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2524 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2525 commands); 2526 2527 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2528 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2529 2530 cwr->lowest_tsn = ntohl(cwr->lowest_tsn); 2531 2532 /* Does this CWR ack the last sent congestion notification? */ 2533 if (TSN_lte(asoc->last_ecne_tsn, cwr->lowest_tsn)) { 2534 /* Stop sending ECNE. */ 2535 sctp_add_cmd_sf(commands, 2536 SCTP_CMD_ECN_CWR, 2537 SCTP_U32(cwr->lowest_tsn)); 2538 } 2539 return SCTP_DISPOSITION_CONSUME; 2540 } 2541 2542 /* 2543 * sctp_sf_do_ecne 2544 * 2545 * Section: Appendix A: Explicit Congestion Notification 2546 * 2547 * ECN-Echo 2548 * 2549 * RFC 2481 details a specific bit for a receiver to send back in its 2550 * TCP acknowledgements to notify the sender of the Congestion 2551 * Experienced (CE) bit having arrived from the network. For SCTP this 2552 * same indication is made by including the ECNE chunk. This chunk 2553 * contains one data element, i.e. the lowest TSN associated with the IP 2554 * datagram marked with the CE bit..... 2555 * 2556 * Verification Tag: 8.5 Verification Tag [Normal verification] 2557 * Inputs 2558 * (endpoint, asoc, chunk) 2559 * 2560 * Outputs 2561 * (asoc, reply_msg, msg_up, timers, counters) 2562 * 2563 * The return value is the disposition of the chunk. 2564 */ 2565 sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, 2566 const struct sctp_association *asoc, 2567 const sctp_subtype_t type, 2568 void *arg, 2569 sctp_cmd_seq_t *commands) 2570 { 2571 sctp_ecnehdr_t *ecne; 2572 struct sctp_chunk *chunk = arg; 2573 2574 if (!sctp_vtag_verify(chunk, asoc)) 2575 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2576 2577 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2578 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2579 commands); 2580 2581 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2582 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2583 2584 /* If this is a newer ECNE than the last CWR packet we sent out */ 2585 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2586 SCTP_U32(ntohl(ecne->lowest_tsn))); 2587 2588 return SCTP_DISPOSITION_CONSUME; 2589 } 2590 2591 /* 2592 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2593 * 2594 * The SCTP endpoint MUST always acknowledge the reception of each valid 2595 * DATA chunk. 2596 * 2597 * The guidelines on delayed acknowledgement algorithm specified in 2598 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2599 * acknowledgement SHOULD be generated for at least every second packet 2600 * (not every second DATA chunk) received, and SHOULD be generated within 2601 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2602 * situations it may be beneficial for an SCTP transmitter to be more 2603 * conservative than the algorithms detailed in this document allow. 2604 * However, an SCTP transmitter MUST NOT be more aggressive than the 2605 * following algorithms allow. 2606 * 2607 * A SCTP receiver MUST NOT generate more than one SACK for every 2608 * incoming packet, other than to update the offered window as the 2609 * receiving application consumes new data. 2610 * 2611 * Verification Tag: 8.5 Verification Tag [Normal verification] 2612 * 2613 * Inputs 2614 * (endpoint, asoc, chunk) 2615 * 2616 * Outputs 2617 * (asoc, reply_msg, msg_up, timers, counters) 2618 * 2619 * The return value is the disposition of the chunk. 2620 */ 2621 sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, 2622 const struct sctp_association *asoc, 2623 const sctp_subtype_t type, 2624 void *arg, 2625 sctp_cmd_seq_t *commands) 2626 { 2627 struct sctp_chunk *chunk = arg; 2628 int error; 2629 2630 if (!sctp_vtag_verify(chunk, asoc)) { 2631 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2632 SCTP_NULL()); 2633 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2634 } 2635 2636 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2637 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2638 commands); 2639 2640 error = sctp_eat_data(asoc, chunk, commands ); 2641 switch (error) { 2642 case SCTP_IERROR_NO_ERROR: 2643 break; 2644 case SCTP_IERROR_HIGH_TSN: 2645 case SCTP_IERROR_BAD_STREAM: 2646 goto discard_noforce; 2647 case SCTP_IERROR_DUP_TSN: 2648 case SCTP_IERROR_IGNORE_TSN: 2649 goto discard_force; 2650 case SCTP_IERROR_NO_DATA: 2651 goto consume; 2652 default: 2653 BUG(); 2654 } 2655 2656 if (asoc->autoclose) { 2657 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2658 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2659 } 2660 2661 /* If this is the last chunk in a packet, we need to count it 2662 * toward sack generation. Note that we need to SACK every 2663 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2664 * THEM. We elect to NOT generate SACK's if the chunk fails 2665 * the verification tag test. 2666 * 2667 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2668 * 2669 * The SCTP endpoint MUST always acknowledge the reception of 2670 * each valid DATA chunk. 2671 * 2672 * The guidelines on delayed acknowledgement algorithm 2673 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2674 * Specifically, an acknowledgement SHOULD be generated for at 2675 * least every second packet (not every second DATA chunk) 2676 * received, and SHOULD be generated within 200 ms of the 2677 * arrival of any unacknowledged DATA chunk. In some 2678 * situations it may be beneficial for an SCTP transmitter to 2679 * be more conservative than the algorithms detailed in this 2680 * document allow. However, an SCTP transmitter MUST NOT be 2681 * more aggressive than the following algorithms allow. 2682 */ 2683 if (chunk->end_of_packet) { 2684 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2685 2686 /* Start the SACK timer. */ 2687 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2688 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 2689 } 2690 2691 return SCTP_DISPOSITION_CONSUME; 2692 2693 discard_force: 2694 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2695 * 2696 * When a packet arrives with duplicate DATA chunk(s) and with 2697 * no new DATA chunk(s), the endpoint MUST immediately send a 2698 * SACK with no delay. If a packet arrives with duplicate 2699 * DATA chunk(s) bundled with new DATA chunks, the endpoint 2700 * MAY immediately send a SACK. Normally receipt of duplicate 2701 * DATA chunks will occur when the original SACK chunk was lost 2702 * and the peer's RTO has expired. The duplicate TSN number(s) 2703 * SHOULD be reported in the SACK as duplicate. 2704 */ 2705 /* In our case, we split the MAY SACK advice up whether or not 2706 * the last chunk is a duplicate.' 2707 */ 2708 if (chunk->end_of_packet) 2709 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2710 return SCTP_DISPOSITION_DISCARD; 2711 2712 discard_noforce: 2713 if (chunk->end_of_packet) { 2714 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 2715 2716 /* Start the SACK timer. */ 2717 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2718 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 2719 } 2720 return SCTP_DISPOSITION_DISCARD; 2721 consume: 2722 return SCTP_DISPOSITION_CONSUME; 2723 2724 } 2725 2726 /* 2727 * sctp_sf_eat_data_fast_4_4 2728 * 2729 * Section: 4 (4) 2730 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 2731 * DATA chunks without delay. 2732 * 2733 * Verification Tag: 8.5 Verification Tag [Normal verification] 2734 * Inputs 2735 * (endpoint, asoc, chunk) 2736 * 2737 * Outputs 2738 * (asoc, reply_msg, msg_up, timers, counters) 2739 * 2740 * The return value is the disposition of the chunk. 2741 */ 2742 sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, 2743 const struct sctp_association *asoc, 2744 const sctp_subtype_t type, 2745 void *arg, 2746 sctp_cmd_seq_t *commands) 2747 { 2748 struct sctp_chunk *chunk = arg; 2749 int error; 2750 2751 if (!sctp_vtag_verify(chunk, asoc)) { 2752 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2753 SCTP_NULL()); 2754 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2755 } 2756 2757 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2758 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2759 commands); 2760 2761 error = sctp_eat_data(asoc, chunk, commands ); 2762 switch (error) { 2763 case SCTP_IERROR_NO_ERROR: 2764 case SCTP_IERROR_HIGH_TSN: 2765 case SCTP_IERROR_DUP_TSN: 2766 case SCTP_IERROR_IGNORE_TSN: 2767 case SCTP_IERROR_BAD_STREAM: 2768 break; 2769 case SCTP_IERROR_NO_DATA: 2770 goto consume; 2771 default: 2772 BUG(); 2773 } 2774 2775 /* Go a head and force a SACK, since we are shutting down. */ 2776 2777 /* Implementor's Guide. 2778 * 2779 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 2780 * respond to each received packet containing one or more DATA chunk(s) 2781 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 2782 */ 2783 if (chunk->end_of_packet) { 2784 /* We must delay the chunk creation since the cumulative 2785 * TSN has not been updated yet. 2786 */ 2787 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 2788 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 2789 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2790 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2791 } 2792 2793 consume: 2794 return SCTP_DISPOSITION_CONSUME; 2795 } 2796 2797 /* 2798 * Section: 6.2 Processing a Received SACK 2799 * D) Any time a SACK arrives, the endpoint performs the following: 2800 * 2801 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 2802 * then drop the SACK. Since Cumulative TSN Ack is monotonically 2803 * increasing, a SACK whose Cumulative TSN Ack is less than the 2804 * Cumulative TSN Ack Point indicates an out-of-order SACK. 2805 * 2806 * ii) Set rwnd equal to the newly received a_rwnd minus the number 2807 * of bytes still outstanding after processing the Cumulative TSN Ack 2808 * and the Gap Ack Blocks. 2809 * 2810 * iii) If the SACK is missing a TSN that was previously 2811 * acknowledged via a Gap Ack Block (e.g., the data receiver 2812 * reneged on the data), then mark the corresponding DATA chunk 2813 * as available for retransmit: Mark it as missing for fast 2814 * retransmit as described in Section 7.2.4 and if no retransmit 2815 * timer is running for the destination address to which the DATA 2816 * chunk was originally transmitted, then T3-rtx is started for 2817 * that destination address. 2818 * 2819 * Verification Tag: 8.5 Verification Tag [Normal verification] 2820 * 2821 * Inputs 2822 * (endpoint, asoc, chunk) 2823 * 2824 * Outputs 2825 * (asoc, reply_msg, msg_up, timers, counters) 2826 * 2827 * The return value is the disposition of the chunk. 2828 */ 2829 sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 2830 const struct sctp_association *asoc, 2831 const sctp_subtype_t type, 2832 void *arg, 2833 sctp_cmd_seq_t *commands) 2834 { 2835 struct sctp_chunk *chunk = arg; 2836 sctp_sackhdr_t *sackh; 2837 __u32 ctsn; 2838 2839 if (!sctp_vtag_verify(chunk, asoc)) 2840 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2841 2842 /* Make sure that the SACK chunk has a valid length. */ 2843 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 2844 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2845 commands); 2846 2847 /* Pull the SACK chunk from the data buffer */ 2848 sackh = sctp_sm_pull_sack(chunk); 2849 /* Was this a bogus SACK? */ 2850 if (!sackh) 2851 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2852 chunk->subh.sack_hdr = sackh; 2853 ctsn = ntohl(sackh->cum_tsn_ack); 2854 2855 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 2856 * Ack Point, then drop the SACK. Since Cumulative TSN 2857 * Ack is monotonically increasing, a SACK whose 2858 * Cumulative TSN Ack is less than the Cumulative TSN Ack 2859 * Point indicates an out-of-order SACK. 2860 */ 2861 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2862 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2863 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2864 return SCTP_DISPOSITION_DISCARD; 2865 } 2866 2867 /* Return this SACK for further processing. */ 2868 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 2869 2870 /* Note: We do the rest of the work on the PROCESS_SACK 2871 * sideeffect. 2872 */ 2873 return SCTP_DISPOSITION_CONSUME; 2874 } 2875 2876 /* 2877 * Generate an ABORT in response to a packet. 2878 * 2879 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 2880 * 2881 * 8) The receiver should respond to the sender of the OOTB packet with 2882 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 2883 * MUST fill in the Verification Tag field of the outbound packet 2884 * with the value found in the Verification Tag field of the OOTB 2885 * packet and set the T-bit in the Chunk Flags to indicate that the 2886 * Verification Tag is reflected. After sending this ABORT, the 2887 * receiver of the OOTB packet shall discard the OOTB packet and take 2888 * no further action. 2889 * 2890 * Verification Tag: 2891 * 2892 * The return value is the disposition of the chunk. 2893 */ 2894 sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 2895 const struct sctp_association *asoc, 2896 const sctp_subtype_t type, 2897 void *arg, 2898 sctp_cmd_seq_t *commands) 2899 { 2900 struct sctp_packet *packet = NULL; 2901 struct sctp_chunk *chunk = arg; 2902 struct sctp_chunk *abort; 2903 2904 packet = sctp_ootb_pkt_new(asoc, chunk); 2905 2906 if (packet) { 2907 /* Make an ABORT. The T bit will be set if the asoc 2908 * is NULL. 2909 */ 2910 abort = sctp_make_abort(asoc, chunk, 0); 2911 if (!abort) { 2912 sctp_ootb_pkt_free(packet); 2913 return SCTP_DISPOSITION_NOMEM; 2914 } 2915 2916 /* Reflect vtag if T-Bit is set */ 2917 if (sctp_test_T_bit(abort)) 2918 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 2919 2920 /* Set the skb to the belonging sock for accounting. */ 2921 abort->skb->sk = ep->base.sk; 2922 2923 sctp_packet_append_chunk(packet, abort); 2924 2925 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 2926 SCTP_PACKET(packet)); 2927 2928 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 2929 2930 return SCTP_DISPOSITION_CONSUME; 2931 } 2932 2933 return SCTP_DISPOSITION_NOMEM; 2934 } 2935 2936 /* 2937 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 2938 * event as ULP notification for each cause included in the chunk. 2939 * 2940 * API 5.3.1.3 - SCTP_REMOTE_ERROR 2941 * 2942 * The return value is the disposition of the chunk. 2943 */ 2944 sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, 2945 const struct sctp_association *asoc, 2946 const sctp_subtype_t type, 2947 void *arg, 2948 sctp_cmd_seq_t *commands) 2949 { 2950 struct sctp_chunk *chunk = arg; 2951 struct sctp_ulpevent *ev; 2952 2953 if (!sctp_vtag_verify(chunk, asoc)) 2954 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 2955 2956 /* Make sure that the ERROR chunk has a valid length. */ 2957 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2958 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 2959 commands); 2960 2961 while (chunk->chunk_end > chunk->skb->data) { 2962 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 2963 GFP_ATOMIC); 2964 if (!ev) 2965 goto nomem; 2966 2967 if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP, 2968 SCTP_ULPEVENT(ev))) { 2969 sctp_ulpevent_free(ev); 2970 goto nomem; 2971 } 2972 2973 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 2974 SCTP_CHUNK(chunk)); 2975 } 2976 return SCTP_DISPOSITION_CONSUME; 2977 2978 nomem: 2979 return SCTP_DISPOSITION_NOMEM; 2980 } 2981 2982 /* 2983 * Process an inbound SHUTDOWN ACK. 2984 * 2985 * From Section 9.2: 2986 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 2987 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 2988 * peer, and remove all record of the association. 2989 * 2990 * The return value is the disposition. 2991 */ 2992 sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, 2993 const struct sctp_association *asoc, 2994 const sctp_subtype_t type, 2995 void *arg, 2996 sctp_cmd_seq_t *commands) 2997 { 2998 struct sctp_chunk *chunk = arg; 2999 struct sctp_chunk *reply; 3000 struct sctp_ulpevent *ev; 3001 3002 if (!sctp_vtag_verify(chunk, asoc)) 3003 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3004 3005 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3006 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3007 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3008 commands); 3009 3010 /* 10.2 H) SHUTDOWN COMPLETE notification 3011 * 3012 * When SCTP completes the shutdown procedures (section 9.2) this 3013 * notification is passed to the upper layer. 3014 */ 3015 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3016 0, 0, 0, GFP_ATOMIC); 3017 if (!ev) 3018 goto nomem; 3019 3020 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3021 3022 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3023 * stop the T2-shutdown timer, 3024 */ 3025 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3026 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3027 3028 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3029 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3030 3031 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3032 reply = sctp_make_shutdown_complete(asoc, chunk); 3033 if (!reply) 3034 goto nomem; 3035 3036 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3037 SCTP_STATE(SCTP_STATE_CLOSED)); 3038 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 3039 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3040 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3041 3042 /* ...and remove all record of the association. */ 3043 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3044 return SCTP_DISPOSITION_DELETE_TCB; 3045 3046 nomem: 3047 return SCTP_DISPOSITION_NOMEM; 3048 } 3049 3050 /* 3051 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3052 * 3053 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3054 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3055 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3056 * packet must fill in the Verification Tag field of the outbound 3057 * packet with the Verification Tag received in the SHUTDOWN ACK and 3058 * set the T-bit in the Chunk Flags to indicate that the Verification 3059 * Tag is reflected. 3060 * 3061 * 8) The receiver should respond to the sender of the OOTB packet with 3062 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3063 * MUST fill in the Verification Tag field of the outbound packet 3064 * with the value found in the Verification Tag field of the OOTB 3065 * packet and set the T-bit in the Chunk Flags to indicate that the 3066 * Verification Tag is reflected. After sending this ABORT, the 3067 * receiver of the OOTB packet shall discard the OOTB packet and take 3068 * no further action. 3069 */ 3070 sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 3071 const struct sctp_association *asoc, 3072 const sctp_subtype_t type, 3073 void *arg, 3074 sctp_cmd_seq_t *commands) 3075 { 3076 struct sctp_chunk *chunk = arg; 3077 struct sk_buff *skb = chunk->skb; 3078 sctp_chunkhdr_t *ch; 3079 __u8 *ch_end; 3080 int ootb_shut_ack = 0; 3081 3082 SCTP_INC_STATS(SCTP_MIB_OUTOFBLUES); 3083 3084 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3085 do { 3086 /* Break out if chunk length is less then minimal. */ 3087 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3088 break; 3089 3090 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3091 3092 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3093 ootb_shut_ack = 1; 3094 3095 /* RFC 2960, Section 3.3.7 3096 * Moreover, under any circumstances, an endpoint that 3097 * receives an ABORT MUST NOT respond to that ABORT by 3098 * sending an ABORT of its own. 3099 */ 3100 if (SCTP_CID_ABORT == ch->type) 3101 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3102 3103 ch = (sctp_chunkhdr_t *) ch_end; 3104 } while (ch_end < skb->tail); 3105 3106 if (ootb_shut_ack) 3107 sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); 3108 else 3109 sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); 3110 3111 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3112 } 3113 3114 /* 3115 * Handle an "Out of the blue" SHUTDOWN ACK. 3116 * 3117 * Section: 8.4 5, sctpimpguide 2.41. 3118 * 3119 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3120 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3121 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3122 * packet must fill in the Verification Tag field of the outbound 3123 * packet with the Verification Tag received in the SHUTDOWN ACK and 3124 * set the T-bit in the Chunk Flags to indicate that the Verification 3125 * Tag is reflected. 3126 * 3127 * Inputs 3128 * (endpoint, asoc, type, arg, commands) 3129 * 3130 * Outputs 3131 * (sctp_disposition_t) 3132 * 3133 * The return value is the disposition of the chunk. 3134 */ 3135 static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 3136 const struct sctp_association *asoc, 3137 const sctp_subtype_t type, 3138 void *arg, 3139 sctp_cmd_seq_t *commands) 3140 { 3141 struct sctp_packet *packet = NULL; 3142 struct sctp_chunk *chunk = arg; 3143 struct sctp_chunk *shut; 3144 3145 packet = sctp_ootb_pkt_new(asoc, chunk); 3146 3147 if (packet) { 3148 /* Make an SHUTDOWN_COMPLETE. 3149 * The T bit will be set if the asoc is NULL. 3150 */ 3151 shut = sctp_make_shutdown_complete(asoc, chunk); 3152 if (!shut) { 3153 sctp_ootb_pkt_free(packet); 3154 return SCTP_DISPOSITION_NOMEM; 3155 } 3156 3157 /* Reflect vtag if T-Bit is set */ 3158 if (sctp_test_T_bit(shut)) 3159 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3160 3161 /* Set the skb to the belonging sock for accounting. */ 3162 shut->skb->sk = ep->base.sk; 3163 3164 sctp_packet_append_chunk(packet, shut); 3165 3166 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3167 SCTP_PACKET(packet)); 3168 3169 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3170 3171 /* If the chunk length is invalid, we don't want to process 3172 * the reset of the packet. 3173 */ 3174 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3175 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3176 3177 return SCTP_DISPOSITION_CONSUME; 3178 } 3179 3180 return SCTP_DISPOSITION_NOMEM; 3181 } 3182 3183 /* 3184 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3185 * 3186 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3187 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3188 * procedures in section 8.4 SHOULD be followed, in other words it 3189 * should be treated as an Out Of The Blue packet. 3190 * [This means that we do NOT check the Verification Tag on these 3191 * chunks. --piggy ] 3192 * 3193 */ 3194 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, 3195 const struct sctp_association *asoc, 3196 const sctp_subtype_t type, 3197 void *arg, 3198 sctp_cmd_seq_t *commands) 3199 { 3200 /* Although we do have an association in this case, it corresponds 3201 * to a restarted association. So the packet is treated as an OOTB 3202 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3203 * called with a NULL association. 3204 */ 3205 return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); 3206 } 3207 3208 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3209 sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, 3210 const struct sctp_association *asoc, 3211 const sctp_subtype_t type, void *arg, 3212 sctp_cmd_seq_t *commands) 3213 { 3214 struct sctp_chunk *chunk = arg; 3215 struct sctp_chunk *asconf_ack = NULL; 3216 sctp_addiphdr_t *hdr; 3217 __u32 serial; 3218 3219 if (!sctp_vtag_verify(chunk, asoc)) { 3220 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3221 SCTP_NULL()); 3222 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3223 } 3224 3225 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3226 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3227 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3228 commands); 3229 3230 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3231 serial = ntohl(hdr->serial); 3232 3233 /* ADDIP 4.2 C1) Compare the value of the serial number to the value 3234 * the endpoint stored in a new association variable 3235 * 'Peer-Serial-Number'. 3236 */ 3237 if (serial == asoc->peer.addip_serial + 1) { 3238 /* ADDIP 4.2 C2) If the value found in the serial number is 3239 * equal to the ('Peer-Serial-Number' + 1), the endpoint MUST 3240 * do V1-V5. 3241 */ 3242 asconf_ack = sctp_process_asconf((struct sctp_association *) 3243 asoc, chunk); 3244 if (!asconf_ack) 3245 return SCTP_DISPOSITION_NOMEM; 3246 } else if (serial == asoc->peer.addip_serial) { 3247 /* ADDIP 4.2 C3) If the value found in the serial number is 3248 * equal to the value stored in the 'Peer-Serial-Number' 3249 * IMPLEMENTATION NOTE: As an optimization a receiver may wish 3250 * to save the last ASCONF-ACK for some predetermined period of 3251 * time and instead of re-processing the ASCONF (with the same 3252 * serial number) it may just re-transmit the ASCONF-ACK. 3253 */ 3254 if (asoc->addip_last_asconf_ack) 3255 asconf_ack = asoc->addip_last_asconf_ack; 3256 else 3257 return SCTP_DISPOSITION_DISCARD; 3258 } else { 3259 /* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since 3260 * it must be either a stale packet or from an attacker. 3261 */ 3262 return SCTP_DISPOSITION_DISCARD; 3263 } 3264 3265 /* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent 3266 * back to the source address contained in the IP header of the ASCONF 3267 * being responded to. 3268 */ 3269 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3270 3271 return SCTP_DISPOSITION_CONSUME; 3272 } 3273 3274 /* 3275 * ADDIP Section 4.3 General rules for address manipulation 3276 * When building TLV parameters for the ASCONF Chunk that will add or 3277 * delete IP addresses the D0 to D13 rules should be applied: 3278 */ 3279 sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, 3280 const struct sctp_association *asoc, 3281 const sctp_subtype_t type, void *arg, 3282 sctp_cmd_seq_t *commands) 3283 { 3284 struct sctp_chunk *asconf_ack = arg; 3285 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3286 struct sctp_chunk *abort; 3287 sctp_addiphdr_t *addip_hdr; 3288 __u32 sent_serial, rcvd_serial; 3289 3290 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3291 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3292 SCTP_NULL()); 3293 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3294 } 3295 3296 /* Make sure that the ADDIP chunk has a valid length. */ 3297 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3298 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3299 commands); 3300 3301 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3302 rcvd_serial = ntohl(addip_hdr->serial); 3303 3304 if (last_asconf) { 3305 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3306 sent_serial = ntohl(addip_hdr->serial); 3307 } else { 3308 sent_serial = asoc->addip_serial - 1; 3309 } 3310 3311 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3312 * equal to the next serial number to be used but no ASCONF chunk is 3313 * outstanding the endpoint MUST ABORT the association. Note that a 3314 * sequence number is greater than if it is no more than 2^^31-1 3315 * larger than the current sequence number (using serial arithmetic). 3316 */ 3317 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3318 !(asoc->addip_last_asconf)) { 3319 abort = sctp_make_abort(asoc, asconf_ack, 3320 sizeof(sctp_errhdr_t)); 3321 if (abort) { 3322 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, NULL, 0); 3323 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3324 SCTP_CHUNK(abort)); 3325 } 3326 /* We are going to ABORT, so we might as well stop 3327 * processing the rest of the chunks in the packet. 3328 */ 3329 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3330 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3331 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3332 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3333 SCTP_U32(SCTP_ERROR_ASCONF_ACK)); 3334 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3335 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3336 return SCTP_DISPOSITION_ABORT; 3337 } 3338 3339 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3340 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3341 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3342 3343 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3344 asconf_ack)) 3345 return SCTP_DISPOSITION_CONSUME; 3346 3347 abort = sctp_make_abort(asoc, asconf_ack, 3348 sizeof(sctp_errhdr_t)); 3349 if (abort) { 3350 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, NULL, 0); 3351 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3352 SCTP_CHUNK(abort)); 3353 } 3354 /* We are going to ABORT, so we might as well stop 3355 * processing the rest of the chunks in the packet. 3356 */ 3357 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3358 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3359 SCTP_U32(SCTP_ERROR_ASCONF_ACK)); 3360 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3361 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3362 return SCTP_DISPOSITION_ABORT; 3363 } 3364 3365 return SCTP_DISPOSITION_DISCARD; 3366 } 3367 3368 /* 3369 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3370 * 3371 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3372 * its cumulative TSN point to the value carried in the FORWARD TSN 3373 * chunk, and then MUST further advance its cumulative TSN point locally 3374 * if possible. 3375 * After the above processing, the data receiver MUST stop reporting any 3376 * missing TSNs earlier than or equal to the new cumulative TSN point. 3377 * 3378 * Verification Tag: 8.5 Verification Tag [Normal verification] 3379 * 3380 * The return value is the disposition of the chunk. 3381 */ 3382 sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 3383 const struct sctp_association *asoc, 3384 const sctp_subtype_t type, 3385 void *arg, 3386 sctp_cmd_seq_t *commands) 3387 { 3388 struct sctp_chunk *chunk = arg; 3389 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3390 __u16 len; 3391 __u32 tsn; 3392 3393 if (!sctp_vtag_verify(chunk, asoc)) { 3394 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3395 SCTP_NULL()); 3396 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3397 } 3398 3399 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3400 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3401 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3402 commands); 3403 3404 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3405 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3406 len = ntohs(chunk->chunk_hdr->length); 3407 len -= sizeof(struct sctp_chunkhdr); 3408 skb_pull(chunk->skb, len); 3409 3410 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3411 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3412 3413 /* The TSN is too high--silently discard the chunk and count on it 3414 * getting retransmitted later. 3415 */ 3416 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3417 goto discard_noforce; 3418 3419 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3420 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3421 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3422 SCTP_CHUNK(chunk)); 3423 3424 /* Count this as receiving DATA. */ 3425 if (asoc->autoclose) { 3426 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3427 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3428 } 3429 3430 /* FIXME: For now send a SACK, but DATA processing may 3431 * send another. 3432 */ 3433 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3434 /* Start the SACK timer. */ 3435 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3436 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 3437 3438 return SCTP_DISPOSITION_CONSUME; 3439 3440 discard_noforce: 3441 return SCTP_DISPOSITION_DISCARD; 3442 } 3443 3444 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3445 const struct sctp_endpoint *ep, 3446 const struct sctp_association *asoc, 3447 const sctp_subtype_t type, 3448 void *arg, 3449 sctp_cmd_seq_t *commands) 3450 { 3451 struct sctp_chunk *chunk = arg; 3452 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3453 __u16 len; 3454 __u32 tsn; 3455 3456 if (!sctp_vtag_verify(chunk, asoc)) { 3457 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3458 SCTP_NULL()); 3459 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3460 } 3461 3462 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3463 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3464 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3465 commands); 3466 3467 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3468 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3469 len = ntohs(chunk->chunk_hdr->length); 3470 len -= sizeof(struct sctp_chunkhdr); 3471 skb_pull(chunk->skb, len); 3472 3473 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3474 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __FUNCTION__, tsn); 3475 3476 /* The TSN is too high--silently discard the chunk and count on it 3477 * getting retransmitted later. 3478 */ 3479 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3480 goto gen_shutdown; 3481 3482 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3483 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3484 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3485 SCTP_CHUNK(chunk)); 3486 3487 /* Go a head and force a SACK, since we are shutting down. */ 3488 gen_shutdown: 3489 /* Implementor's Guide. 3490 * 3491 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3492 * respond to each received packet containing one or more DATA chunk(s) 3493 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3494 */ 3495 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3496 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3497 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3498 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3499 3500 return SCTP_DISPOSITION_CONSUME; 3501 } 3502 3503 /* 3504 * Process an unknown chunk. 3505 * 3506 * Section: 3.2. Also, 2.1 in the implementor's guide. 3507 * 3508 * Chunk Types are encoded such that the highest-order two bits specify 3509 * the action that must be taken if the processing endpoint does not 3510 * recognize the Chunk Type. 3511 * 3512 * 00 - Stop processing this SCTP packet and discard it, do not process 3513 * any further chunks within it. 3514 * 3515 * 01 - Stop processing this SCTP packet and discard it, do not process 3516 * any further chunks within it, and report the unrecognized 3517 * chunk in an 'Unrecognized Chunk Type'. 3518 * 3519 * 10 - Skip this chunk and continue processing. 3520 * 3521 * 11 - Skip this chunk and continue processing, but report in an ERROR 3522 * Chunk using the 'Unrecognized Chunk Type' cause of error. 3523 * 3524 * The return value is the disposition of the chunk. 3525 */ 3526 sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, 3527 const struct sctp_association *asoc, 3528 const sctp_subtype_t type, 3529 void *arg, 3530 sctp_cmd_seq_t *commands) 3531 { 3532 struct sctp_chunk *unk_chunk = arg; 3533 struct sctp_chunk *err_chunk; 3534 sctp_chunkhdr_t *hdr; 3535 3536 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 3537 3538 if (!sctp_vtag_verify(unk_chunk, asoc)) 3539 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3540 3541 /* Make sure that the chunk has a valid length. 3542 * Since we don't know the chunk type, we use a general 3543 * chunkhdr structure to make a comparison. 3544 */ 3545 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 3546 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 3547 commands); 3548 3549 switch (type.chunk & SCTP_CID_ACTION_MASK) { 3550 case SCTP_CID_ACTION_DISCARD: 3551 /* Discard the packet. */ 3552 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3553 break; 3554 case SCTP_CID_ACTION_DISCARD_ERR: 3555 /* Discard the packet. */ 3556 sctp_sf_pdiscard(ep, asoc, type, arg, commands); 3557 3558 /* Generate an ERROR chunk as response. */ 3559 hdr = unk_chunk->chunk_hdr; 3560 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3561 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3562 WORD_ROUND(ntohs(hdr->length))); 3563 if (err_chunk) { 3564 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3565 SCTP_CHUNK(err_chunk)); 3566 } 3567 return SCTP_DISPOSITION_CONSUME; 3568 break; 3569 case SCTP_CID_ACTION_SKIP: 3570 /* Skip the chunk. */ 3571 return SCTP_DISPOSITION_DISCARD; 3572 break; 3573 case SCTP_CID_ACTION_SKIP_ERR: 3574 /* Generate an ERROR chunk as response. */ 3575 hdr = unk_chunk->chunk_hdr; 3576 err_chunk = sctp_make_op_error(asoc, unk_chunk, 3577 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 3578 WORD_ROUND(ntohs(hdr->length))); 3579 if (err_chunk) { 3580 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3581 SCTP_CHUNK(err_chunk)); 3582 } 3583 /* Skip the chunk. */ 3584 return SCTP_DISPOSITION_CONSUME; 3585 break; 3586 default: 3587 break; 3588 } 3589 3590 return SCTP_DISPOSITION_DISCARD; 3591 } 3592 3593 /* 3594 * Discard the chunk. 3595 * 3596 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 3597 * [Too numerous to mention...] 3598 * Verification Tag: No verification needed. 3599 * Inputs 3600 * (endpoint, asoc, chunk) 3601 * 3602 * Outputs 3603 * (asoc, reply_msg, msg_up, timers, counters) 3604 * 3605 * The return value is the disposition of the chunk. 3606 */ 3607 sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 3608 const struct sctp_association *asoc, 3609 const sctp_subtype_t type, 3610 void *arg, 3611 sctp_cmd_seq_t *commands) 3612 { 3613 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 3614 return SCTP_DISPOSITION_DISCARD; 3615 } 3616 3617 /* 3618 * Discard the whole packet. 3619 * 3620 * Section: 8.4 2) 3621 * 3622 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 3623 * silently discard the OOTB packet and take no further action. 3624 * 3625 * Verification Tag: No verification necessary 3626 * 3627 * Inputs 3628 * (endpoint, asoc, chunk) 3629 * 3630 * Outputs 3631 * (asoc, reply_msg, msg_up, timers, counters) 3632 * 3633 * The return value is the disposition of the chunk. 3634 */ 3635 sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, 3636 const struct sctp_association *asoc, 3637 const sctp_subtype_t type, 3638 void *arg, 3639 sctp_cmd_seq_t *commands) 3640 { 3641 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3642 3643 return SCTP_DISPOSITION_CONSUME; 3644 } 3645 3646 3647 /* 3648 * The other end is violating protocol. 3649 * 3650 * Section: Not specified 3651 * Verification Tag: Not specified 3652 * Inputs 3653 * (endpoint, asoc, chunk) 3654 * 3655 * Outputs 3656 * (asoc, reply_msg, msg_up, timers, counters) 3657 * 3658 * We simply tag the chunk as a violation. The state machine will log 3659 * the violation and continue. 3660 */ 3661 sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, 3662 const struct sctp_association *asoc, 3663 const sctp_subtype_t type, 3664 void *arg, 3665 sctp_cmd_seq_t *commands) 3666 { 3667 return SCTP_DISPOSITION_VIOLATION; 3668 } 3669 3670 3671 /* 3672 * Handle a protocol violation when the chunk length is invalid. 3673 * "Invalid" length is identified as smaller then the minimal length a 3674 * given chunk can be. For example, a SACK chunk has invalid length 3675 * if it's length is set to be smaller then the size of sctp_sack_chunk_t. 3676 * 3677 * We inform the other end by sending an ABORT with a Protocol Violation 3678 * error code. 3679 * 3680 * Section: Not specified 3681 * Verification Tag: Nothing to do 3682 * Inputs 3683 * (endpoint, asoc, chunk) 3684 * 3685 * Outputs 3686 * (reply_msg, msg_up, counters) 3687 * 3688 * Generate an ABORT chunk and terminate the association. 3689 */ 3690 sctp_disposition_t sctp_sf_violation_chunklen(const struct sctp_endpoint *ep, 3691 const struct sctp_association *asoc, 3692 const sctp_subtype_t type, 3693 void *arg, 3694 sctp_cmd_seq_t *commands) 3695 { 3696 struct sctp_chunk *chunk = arg; 3697 struct sctp_chunk *abort = NULL; 3698 char err_str[]="The following chunk had invalid length:"; 3699 3700 /* Make the abort chunk. */ 3701 abort = sctp_make_abort_violation(asoc, chunk, err_str, 3702 sizeof(err_str)); 3703 if (!abort) 3704 goto nomem; 3705 3706 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 3707 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 3708 3709 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 3710 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3711 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 3712 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 3713 SCTP_U32(SCTP_ERROR_PROTO_VIOLATION)); 3714 } else { 3715 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3716 SCTP_U32(SCTP_ERROR_PROTO_VIOLATION)); 3717 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 3718 } 3719 3720 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3721 3722 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 3723 3724 return SCTP_DISPOSITION_ABORT; 3725 3726 nomem: 3727 return SCTP_DISPOSITION_NOMEM; 3728 } 3729 3730 /*************************************************************************** 3731 * These are the state functions for handling primitive (Section 10) events. 3732 ***************************************************************************/ 3733 /* 3734 * sctp_sf_do_prm_asoc 3735 * 3736 * Section: 10.1 ULP-to-SCTP 3737 * B) Associate 3738 * 3739 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 3740 * outbound stream count) 3741 * -> association id [,destination transport addr list] [,outbound stream 3742 * count] 3743 * 3744 * This primitive allows the upper layer to initiate an association to a 3745 * specific peer endpoint. 3746 * 3747 * The peer endpoint shall be specified by one of the transport addresses 3748 * which defines the endpoint (see Section 1.4). If the local SCTP 3749 * instance has not been initialized, the ASSOCIATE is considered an 3750 * error. 3751 * [This is not relevant for the kernel implementation since we do all 3752 * initialization at boot time. It we hadn't initialized we wouldn't 3753 * get anywhere near this code.] 3754 * 3755 * An association id, which is a local handle to the SCTP association, 3756 * will be returned on successful establishment of the association. If 3757 * SCTP is not able to open an SCTP association with the peer endpoint, 3758 * an error is returned. 3759 * [In the kernel implementation, the struct sctp_association needs to 3760 * be created BEFORE causing this primitive to run.] 3761 * 3762 * Other association parameters may be returned, including the 3763 * complete destination transport addresses of the peer as well as the 3764 * outbound stream count of the local endpoint. One of the transport 3765 * address from the returned destination addresses will be selected by 3766 * the local endpoint as default primary path for sending SCTP packets 3767 * to this peer. The returned "destination transport addr list" can 3768 * be used by the ULP to change the default primary path or to force 3769 * sending a packet to a specific transport address. [All of this 3770 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 3771 * function.] 3772 * 3773 * Mandatory attributes: 3774 * 3775 * o local SCTP instance name - obtained from the INITIALIZE operation. 3776 * [This is the argument asoc.] 3777 * o destination transport addr - specified as one of the transport 3778 * addresses of the peer endpoint with which the association is to be 3779 * established. 3780 * [This is asoc->peer.active_path.] 3781 * o outbound stream count - the number of outbound streams the ULP 3782 * would like to open towards this peer endpoint. 3783 * [BUG: This is not currently implemented.] 3784 * Optional attributes: 3785 * 3786 * None. 3787 * 3788 * The return value is a disposition. 3789 */ 3790 sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, 3791 const struct sctp_association *asoc, 3792 const sctp_subtype_t type, 3793 void *arg, 3794 sctp_cmd_seq_t *commands) 3795 { 3796 struct sctp_chunk *repl; 3797 3798 /* The comment below says that we enter COOKIE-WAIT AFTER 3799 * sending the INIT, but that doesn't actually work in our 3800 * implementation... 3801 */ 3802 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3803 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 3804 3805 /* RFC 2960 5.1 Normal Establishment of an Association 3806 * 3807 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 3808 * must provide its Verification Tag (Tag_A) in the Initiate 3809 * Tag field. Tag_A SHOULD be a random number in the range of 3810 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 3811 */ 3812 3813 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 3814 if (!repl) 3815 goto nomem; 3816 3817 /* Cast away the const modifier, as we want to just 3818 * rerun it through as a sideffect. 3819 */ 3820 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, 3821 SCTP_ASOC((struct sctp_association *) asoc)); 3822 3823 /* Choose transport for INIT. */ 3824 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 3825 SCTP_CHUNK(repl)); 3826 3827 /* After sending the INIT, "A" starts the T1-init timer and 3828 * enters the COOKIE-WAIT state. 3829 */ 3830 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 3831 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 3832 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 3833 return SCTP_DISPOSITION_CONSUME; 3834 3835 nomem: 3836 return SCTP_DISPOSITION_NOMEM; 3837 } 3838 3839 /* 3840 * Process the SEND primitive. 3841 * 3842 * Section: 10.1 ULP-to-SCTP 3843 * E) Send 3844 * 3845 * Format: SEND(association id, buffer address, byte count [,context] 3846 * [,stream id] [,life time] [,destination transport address] 3847 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 3848 * -> result 3849 * 3850 * This is the main method to send user data via SCTP. 3851 * 3852 * Mandatory attributes: 3853 * 3854 * o association id - local handle to the SCTP association 3855 * 3856 * o buffer address - the location where the user message to be 3857 * transmitted is stored; 3858 * 3859 * o byte count - The size of the user data in number of bytes; 3860 * 3861 * Optional attributes: 3862 * 3863 * o context - an optional 32 bit integer that will be carried in the 3864 * sending failure notification to the ULP if the transportation of 3865 * this User Message fails. 3866 * 3867 * o stream id - to indicate which stream to send the data on. If not 3868 * specified, stream 0 will be used. 3869 * 3870 * o life time - specifies the life time of the user data. The user data 3871 * will not be sent by SCTP after the life time expires. This 3872 * parameter can be used to avoid efforts to transmit stale 3873 * user messages. SCTP notifies the ULP if the data cannot be 3874 * initiated to transport (i.e. sent to the destination via SCTP's 3875 * send primitive) within the life time variable. However, the 3876 * user data will be transmitted if SCTP has attempted to transmit a 3877 * chunk before the life time expired. 3878 * 3879 * o destination transport address - specified as one of the destination 3880 * transport addresses of the peer endpoint to which this packet 3881 * should be sent. Whenever possible, SCTP should use this destination 3882 * transport address for sending the packets, instead of the current 3883 * primary path. 3884 * 3885 * o unorder flag - this flag, if present, indicates that the user 3886 * would like the data delivered in an unordered fashion to the peer 3887 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 3888 * message). 3889 * 3890 * o no-bundle flag - instructs SCTP not to bundle this user data with 3891 * other outbound DATA chunks. SCTP MAY still bundle even when 3892 * this flag is present, when faced with network congestion. 3893 * 3894 * o payload protocol-id - A 32 bit unsigned integer that is to be 3895 * passed to the peer indicating the type of payload protocol data 3896 * being transmitted. This value is passed as opaque data by SCTP. 3897 * 3898 * The return value is the disposition. 3899 */ 3900 sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, 3901 const struct sctp_association *asoc, 3902 const sctp_subtype_t type, 3903 void *arg, 3904 sctp_cmd_seq_t *commands) 3905 { 3906 struct sctp_chunk *chunk = arg; 3907 3908 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 3909 return SCTP_DISPOSITION_CONSUME; 3910 } 3911 3912 /* 3913 * Process the SHUTDOWN primitive. 3914 * 3915 * Section: 10.1: 3916 * C) Shutdown 3917 * 3918 * Format: SHUTDOWN(association id) 3919 * -> result 3920 * 3921 * Gracefully closes an association. Any locally queued user data 3922 * will be delivered to the peer. The association will be terminated only 3923 * after the peer acknowledges all the SCTP packets sent. A success code 3924 * will be returned on successful termination of the association. If 3925 * attempting to terminate the association results in a failure, an error 3926 * code shall be returned. 3927 * 3928 * Mandatory attributes: 3929 * 3930 * o association id - local handle to the SCTP association 3931 * 3932 * Optional attributes: 3933 * 3934 * None. 3935 * 3936 * The return value is the disposition. 3937 */ 3938 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 3939 const struct sctp_endpoint *ep, 3940 const struct sctp_association *asoc, 3941 const sctp_subtype_t type, 3942 void *arg, 3943 sctp_cmd_seq_t *commands) 3944 { 3945 int disposition; 3946 3947 /* From 9.2 Shutdown of an Association 3948 * Upon receipt of the SHUTDOWN primitive from its upper 3949 * layer, the endpoint enters SHUTDOWN-PENDING state and 3950 * remains there until all outstanding data has been 3951 * acknowledged by its peer. The endpoint accepts no new data 3952 * from its upper layer, but retransmits data to the far end 3953 * if necessary to fill gaps. 3954 */ 3955 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3956 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 3957 3958 /* sctpimpguide-05 Section 2.12.2 3959 * The sender of the SHUTDOWN MAY also start an overall guard timer 3960 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 3961 */ 3962 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 3963 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3964 3965 disposition = SCTP_DISPOSITION_CONSUME; 3966 if (sctp_outq_is_empty(&asoc->outqueue)) { 3967 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 3968 arg, commands); 3969 } 3970 return disposition; 3971 } 3972 3973 /* 3974 * Process the ABORT primitive. 3975 * 3976 * Section: 10.1: 3977 * C) Abort 3978 * 3979 * Format: Abort(association id [, cause code]) 3980 * -> result 3981 * 3982 * Ungracefully closes an association. Any locally queued user data 3983 * will be discarded and an ABORT chunk is sent to the peer. A success code 3984 * will be returned on successful abortion of the association. If 3985 * attempting to abort the association results in a failure, an error 3986 * code shall be returned. 3987 * 3988 * Mandatory attributes: 3989 * 3990 * o association id - local handle to the SCTP association 3991 * 3992 * Optional attributes: 3993 * 3994 * o cause code - reason of the abort to be passed to the peer 3995 * 3996 * None. 3997 * 3998 * The return value is the disposition. 3999 */ 4000 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4001 const struct sctp_endpoint *ep, 4002 const struct sctp_association *asoc, 4003 const sctp_subtype_t type, 4004 void *arg, 4005 sctp_cmd_seq_t *commands) 4006 { 4007 /* From 9.1 Abort of an Association 4008 * Upon receipt of the ABORT primitive from its upper 4009 * layer, the endpoint enters CLOSED state and 4010 * discard all outstanding data has been 4011 * acknowledged by its peer. The endpoint accepts no new data 4012 * from its upper layer, but retransmits data to the far end 4013 * if necessary to fill gaps. 4014 */ 4015 struct msghdr *msg = arg; 4016 struct sctp_chunk *abort; 4017 sctp_disposition_t retval; 4018 4019 retval = SCTP_DISPOSITION_CONSUME; 4020 4021 /* Generate ABORT chunk to send the peer. */ 4022 abort = sctp_make_abort_user(asoc, NULL, msg); 4023 if (!abort) 4024 retval = SCTP_DISPOSITION_NOMEM; 4025 else 4026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4027 4028 /* Even if we can't send the ABORT due to low memory delete the 4029 * TCB. This is a departure from our typical NOMEM handling. 4030 */ 4031 4032 /* Delete the established association. */ 4033 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4034 SCTP_U32(SCTP_ERROR_USER_ABORT)); 4035 4036 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4037 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4038 4039 return retval; 4040 } 4041 4042 /* We tried an illegal operation on an association which is closed. */ 4043 sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, 4044 const struct sctp_association *asoc, 4045 const sctp_subtype_t type, 4046 void *arg, 4047 sctp_cmd_seq_t *commands) 4048 { 4049 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4050 return SCTP_DISPOSITION_CONSUME; 4051 } 4052 4053 /* We tried an illegal operation on an association which is shutting 4054 * down. 4055 */ 4056 sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, 4057 const struct sctp_association *asoc, 4058 const sctp_subtype_t type, 4059 void *arg, 4060 sctp_cmd_seq_t *commands) 4061 { 4062 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4063 SCTP_ERROR(-ESHUTDOWN)); 4064 return SCTP_DISPOSITION_CONSUME; 4065 } 4066 4067 /* 4068 * sctp_cookie_wait_prm_shutdown 4069 * 4070 * Section: 4 Note: 2 4071 * Verification Tag: 4072 * Inputs 4073 * (endpoint, asoc) 4074 * 4075 * The RFC does not explicitly address this issue, but is the route through the 4076 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4077 * 4078 * Outputs 4079 * (timers) 4080 */ 4081 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4082 const struct sctp_endpoint *ep, 4083 const struct sctp_association *asoc, 4084 const sctp_subtype_t type, 4085 void *arg, 4086 sctp_cmd_seq_t *commands) 4087 { 4088 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4089 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4090 4091 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4092 SCTP_STATE(SCTP_STATE_CLOSED)); 4093 4094 SCTP_INC_STATS(SCTP_MIB_SHUTDOWNS); 4095 4096 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4097 4098 return SCTP_DISPOSITION_DELETE_TCB; 4099 } 4100 4101 /* 4102 * sctp_cookie_echoed_prm_shutdown 4103 * 4104 * Section: 4 Note: 2 4105 * Verification Tag: 4106 * Inputs 4107 * (endpoint, asoc) 4108 * 4109 * The RFC does not explcitly address this issue, but is the route through the 4110 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4111 * 4112 * Outputs 4113 * (timers) 4114 */ 4115 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4116 const struct sctp_endpoint *ep, 4117 const struct sctp_association *asoc, 4118 const sctp_subtype_t type, 4119 void *arg, sctp_cmd_seq_t *commands) 4120 { 4121 /* There is a single T1 timer, so we should be able to use 4122 * common function with the COOKIE-WAIT state. 4123 */ 4124 return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); 4125 } 4126 4127 /* 4128 * sctp_sf_cookie_wait_prm_abort 4129 * 4130 * Section: 4 Note: 2 4131 * Verification Tag: 4132 * Inputs 4133 * (endpoint, asoc) 4134 * 4135 * The RFC does not explicitly address this issue, but is the route through the 4136 * state table when someone issues an abort while in COOKIE_WAIT state. 4137 * 4138 * Outputs 4139 * (timers) 4140 */ 4141 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4142 const struct sctp_endpoint *ep, 4143 const struct sctp_association *asoc, 4144 const sctp_subtype_t type, 4145 void *arg, 4146 sctp_cmd_seq_t *commands) 4147 { 4148 struct msghdr *msg = arg; 4149 struct sctp_chunk *abort; 4150 sctp_disposition_t retval; 4151 4152 /* Stop T1-init timer */ 4153 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4154 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4155 retval = SCTP_DISPOSITION_CONSUME; 4156 4157 /* Generate ABORT chunk to send the peer */ 4158 abort = sctp_make_abort_user(asoc, NULL, msg); 4159 if (!abort) 4160 retval = SCTP_DISPOSITION_NOMEM; 4161 else 4162 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4163 4164 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4165 SCTP_STATE(SCTP_STATE_CLOSED)); 4166 4167 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4168 4169 /* Even if we can't send the ABORT due to low memory delete the 4170 * TCB. This is a departure from our typical NOMEM handling. 4171 */ 4172 4173 /* Delete the established association. */ 4174 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4175 SCTP_U32(SCTP_ERROR_USER_ABORT)); 4176 4177 return retval; 4178 } 4179 4180 /* 4181 * sctp_sf_cookie_echoed_prm_abort 4182 * 4183 * Section: 4 Note: 3 4184 * Verification Tag: 4185 * Inputs 4186 * (endpoint, asoc) 4187 * 4188 * The RFC does not explcitly address this issue, but is the route through the 4189 * state table when someone issues an abort while in COOKIE_ECHOED state. 4190 * 4191 * Outputs 4192 * (timers) 4193 */ 4194 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4195 const struct sctp_endpoint *ep, 4196 const struct sctp_association *asoc, 4197 const sctp_subtype_t type, 4198 void *arg, 4199 sctp_cmd_seq_t *commands) 4200 { 4201 /* There is a single T1 timer, so we should be able to use 4202 * common function with the COOKIE-WAIT state. 4203 */ 4204 return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); 4205 } 4206 4207 /* 4208 * sctp_sf_shutdown_pending_prm_abort 4209 * 4210 * Inputs 4211 * (endpoint, asoc) 4212 * 4213 * The RFC does not explicitly address this issue, but is the route through the 4214 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 4215 * 4216 * Outputs 4217 * (timers) 4218 */ 4219 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 4220 const struct sctp_endpoint *ep, 4221 const struct sctp_association *asoc, 4222 const sctp_subtype_t type, 4223 void *arg, 4224 sctp_cmd_seq_t *commands) 4225 { 4226 /* Stop the T5-shutdown guard timer. */ 4227 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4228 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4229 4230 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4231 } 4232 4233 /* 4234 * sctp_sf_shutdown_sent_prm_abort 4235 * 4236 * Inputs 4237 * (endpoint, asoc) 4238 * 4239 * The RFC does not explicitly address this issue, but is the route through the 4240 * state table when someone issues an abort while in SHUTDOWN-SENT state. 4241 * 4242 * Outputs 4243 * (timers) 4244 */ 4245 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 4246 const struct sctp_endpoint *ep, 4247 const struct sctp_association *asoc, 4248 const sctp_subtype_t type, 4249 void *arg, 4250 sctp_cmd_seq_t *commands) 4251 { 4252 /* Stop the T2-shutdown timer. */ 4253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4254 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4255 4256 /* Stop the T5-shutdown guard timer. */ 4257 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4258 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4259 4260 return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); 4261 } 4262 4263 /* 4264 * sctp_sf_cookie_echoed_prm_abort 4265 * 4266 * Inputs 4267 * (endpoint, asoc) 4268 * 4269 * The RFC does not explcitly address this issue, but is the route through the 4270 * state table when someone issues an abort while in COOKIE_ECHOED state. 4271 * 4272 * Outputs 4273 * (timers) 4274 */ 4275 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 4276 const struct sctp_endpoint *ep, 4277 const struct sctp_association *asoc, 4278 const sctp_subtype_t type, 4279 void *arg, 4280 sctp_cmd_seq_t *commands) 4281 { 4282 /* The same T2 timer, so we should be able to use 4283 * common function with the SHUTDOWN-SENT state. 4284 */ 4285 return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); 4286 } 4287 4288 /* 4289 * Process the REQUESTHEARTBEAT primitive 4290 * 4291 * 10.1 ULP-to-SCTP 4292 * J) Request Heartbeat 4293 * 4294 * Format: REQUESTHEARTBEAT(association id, destination transport address) 4295 * 4296 * -> result 4297 * 4298 * Instructs the local endpoint to perform a HeartBeat on the specified 4299 * destination transport address of the given association. The returned 4300 * result should indicate whether the transmission of the HEARTBEAT 4301 * chunk to the destination address is successful. 4302 * 4303 * Mandatory attributes: 4304 * 4305 * o association id - local handle to the SCTP association 4306 * 4307 * o destination transport address - the transport address of the 4308 * association on which a heartbeat should be issued. 4309 */ 4310 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 4311 const struct sctp_endpoint *ep, 4312 const struct sctp_association *asoc, 4313 const sctp_subtype_t type, 4314 void *arg, 4315 sctp_cmd_seq_t *commands) 4316 { 4317 return sctp_sf_heartbeat(ep, asoc, type, (struct sctp_transport *)arg, 4318 commands); 4319 } 4320 4321 /* 4322 * ADDIP Section 4.1 ASCONF Chunk Procedures 4323 * When an endpoint has an ASCONF signaled change to be sent to the 4324 * remote endpoint it should do A1 to A9 4325 */ 4326 sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, 4327 const struct sctp_association *asoc, 4328 const sctp_subtype_t type, 4329 void *arg, 4330 sctp_cmd_seq_t *commands) 4331 { 4332 struct sctp_chunk *chunk = arg; 4333 4334 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4335 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4336 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4337 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 4338 return SCTP_DISPOSITION_CONSUME; 4339 } 4340 4341 /* 4342 * Ignore the primitive event 4343 * 4344 * The return value is the disposition of the primitive. 4345 */ 4346 sctp_disposition_t sctp_sf_ignore_primitive( 4347 const struct sctp_endpoint *ep, 4348 const struct sctp_association *asoc, 4349 const sctp_subtype_t type, 4350 void *arg, 4351 sctp_cmd_seq_t *commands) 4352 { 4353 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 4354 return SCTP_DISPOSITION_DISCARD; 4355 } 4356 4357 /*************************************************************************** 4358 * These are the state functions for the OTHER events. 4359 ***************************************************************************/ 4360 4361 /* 4362 * Start the shutdown negotiation. 4363 * 4364 * From Section 9.2: 4365 * Once all its outstanding data has been acknowledged, the endpoint 4366 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 4367 * TSN Ack field the last sequential TSN it has received from the peer. 4368 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 4369 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 4370 * with the updated last sequential TSN received from its peer. 4371 * 4372 * The return value is the disposition. 4373 */ 4374 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 4375 const struct sctp_endpoint *ep, 4376 const struct sctp_association *asoc, 4377 const sctp_subtype_t type, 4378 void *arg, 4379 sctp_cmd_seq_t *commands) 4380 { 4381 struct sctp_chunk *reply; 4382 4383 /* Once all its outstanding data has been acknowledged, the 4384 * endpoint shall send a SHUTDOWN chunk to its peer including 4385 * in the Cumulative TSN Ack field the last sequential TSN it 4386 * has received from the peer. 4387 */ 4388 reply = sctp_make_shutdown(asoc, NULL); 4389 if (!reply) 4390 goto nomem; 4391 4392 /* Set the transport for the SHUTDOWN chunk and the timeout for the 4393 * T2-shutdown timer. 4394 */ 4395 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4396 4397 /* It shall then start the T2-shutdown timer */ 4398 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4399 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4400 4401 if (asoc->autoclose) 4402 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4403 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4404 4405 /* and enter the SHUTDOWN-SENT state. */ 4406 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4407 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 4408 4409 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4410 * 4411 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4412 * or SHUTDOWN-ACK. 4413 */ 4414 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4415 4416 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4417 4418 return SCTP_DISPOSITION_CONSUME; 4419 4420 nomem: 4421 return SCTP_DISPOSITION_NOMEM; 4422 } 4423 4424 /* 4425 * Generate a SHUTDOWN ACK now that everything is SACK'd. 4426 * 4427 * From Section 9.2: 4428 * 4429 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4430 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 4431 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 4432 * endpoint must re-send the SHUTDOWN ACK. 4433 * 4434 * The return value is the disposition. 4435 */ 4436 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 4437 const struct sctp_endpoint *ep, 4438 const struct sctp_association *asoc, 4439 const sctp_subtype_t type, 4440 void *arg, 4441 sctp_cmd_seq_t *commands) 4442 { 4443 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 4444 struct sctp_chunk *reply; 4445 4446 /* There are 2 ways of getting here: 4447 * 1) called in response to a SHUTDOWN chunk 4448 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 4449 * 4450 * For the case (2), the arg parameter is set to NULL. We need 4451 * to check that we have a chunk before accessing it's fields. 4452 */ 4453 if (chunk) { 4454 if (!sctp_vtag_verify(chunk, asoc)) 4455 return sctp_sf_pdiscard(ep, asoc, type, arg, commands); 4456 4457 /* Make sure that the SHUTDOWN chunk has a valid length. */ 4458 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 4459 return sctp_sf_violation_chunklen(ep, asoc, type, arg, 4460 commands); 4461 } 4462 4463 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 4464 * shall send a SHUTDOWN ACK ... 4465 */ 4466 reply = sctp_make_shutdown_ack(asoc, chunk); 4467 if (!reply) 4468 goto nomem; 4469 4470 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 4471 * the T2-shutdown timer. 4472 */ 4473 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4474 4475 /* and start/restart a T2-shutdown timer of its own, */ 4476 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4477 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4478 4479 if (asoc->autoclose) 4480 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4481 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4482 4483 /* Enter the SHUTDOWN-ACK-SENT state. */ 4484 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4485 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 4486 4487 /* sctp-implguide 2.10 Issues with Heartbeating and failover 4488 * 4489 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 4490 * or SHUTDOWN-ACK. 4491 */ 4492 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 4493 4494 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4495 4496 return SCTP_DISPOSITION_CONSUME; 4497 4498 nomem: 4499 return SCTP_DISPOSITION_NOMEM; 4500 } 4501 4502 /* 4503 * Ignore the event defined as other 4504 * 4505 * The return value is the disposition of the event. 4506 */ 4507 sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, 4508 const struct sctp_association *asoc, 4509 const sctp_subtype_t type, 4510 void *arg, 4511 sctp_cmd_seq_t *commands) 4512 { 4513 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 4514 return SCTP_DISPOSITION_DISCARD; 4515 } 4516 4517 /************************************************************ 4518 * These are the state functions for handling timeout events. 4519 ************************************************************/ 4520 4521 /* 4522 * RTX Timeout 4523 * 4524 * Section: 6.3.3 Handle T3-rtx Expiration 4525 * 4526 * Whenever the retransmission timer T3-rtx expires for a destination 4527 * address, do the following: 4528 * [See below] 4529 * 4530 * The return value is the disposition of the chunk. 4531 */ 4532 sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, 4533 const struct sctp_association *asoc, 4534 const sctp_subtype_t type, 4535 void *arg, 4536 sctp_cmd_seq_t *commands) 4537 { 4538 struct sctp_transport *transport = arg; 4539 4540 if (asoc->overall_error_count >= asoc->max_retrans) { 4541 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 4542 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4543 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4544 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4545 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4546 return SCTP_DISPOSITION_DELETE_TCB; 4547 } 4548 4549 /* E1) For the destination address for which the timer 4550 * expires, adjust its ssthresh with rules defined in Section 4551 * 7.2.3 and set the cwnd <- MTU. 4552 */ 4553 4554 /* E2) For the destination address for which the timer 4555 * expires, set RTO <- RTO * 2 ("back off the timer"). The 4556 * maximum value discussed in rule C7 above (RTO.max) may be 4557 * used to provide an upper bound to this doubling operation. 4558 */ 4559 4560 /* E3) Determine how many of the earliest (i.e., lowest TSN) 4561 * outstanding DATA chunks for the address for which the 4562 * T3-rtx has expired will fit into a single packet, subject 4563 * to the MTU constraint for the path corresponding to the 4564 * destination transport address to which the retransmission 4565 * is being sent (this may be different from the address for 4566 * which the timer expires [see Section 6.4]). Call this 4567 * value K. Bundle and retransmit those K DATA chunks in a 4568 * single packet to the destination endpoint. 4569 * 4570 * Note: Any DATA chunks that were sent to the address for 4571 * which the T3-rtx timer expired but did not fit in one MTU 4572 * (rule E3 above), should be marked for retransmission and 4573 * sent as soon as cwnd allows (normally when a SACK arrives). 4574 */ 4575 4576 /* NB: Rules E4 and F1 are implicit in R1. */ 4577 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 4578 4579 /* Do some failure management (Section 8.2). */ 4580 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 4581 4582 return SCTP_DISPOSITION_CONSUME; 4583 } 4584 4585 /* 4586 * Generate delayed SACK on timeout 4587 * 4588 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 4589 * 4590 * The guidelines on delayed acknowledgement algorithm specified in 4591 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 4592 * acknowledgement SHOULD be generated for at least every second packet 4593 * (not every second DATA chunk) received, and SHOULD be generated 4594 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 4595 * some situations it may be beneficial for an SCTP transmitter to be 4596 * more conservative than the algorithms detailed in this document 4597 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 4598 * the following algorithms allow. 4599 */ 4600 sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, 4601 const struct sctp_association *asoc, 4602 const sctp_subtype_t type, 4603 void *arg, 4604 sctp_cmd_seq_t *commands) 4605 { 4606 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4607 return SCTP_DISPOSITION_CONSUME; 4608 } 4609 4610 /* 4611 * sctp_sf_t1_init_timer_expire 4612 * 4613 * Section: 4 Note: 2 4614 * Verification Tag: 4615 * Inputs 4616 * (endpoint, asoc) 4617 * 4618 * RFC 2960 Section 4 Notes 4619 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 4620 * and re-start the T1-init timer without changing state. This MUST 4621 * be repeated up to 'Max.Init.Retransmits' times. After that, the 4622 * endpoint MUST abort the initialization process and report the 4623 * error to SCTP user. 4624 * 4625 * Outputs 4626 * (timers, events) 4627 * 4628 */ 4629 sctp_disposition_t sctp_sf_t1_init_timer_expire(const struct sctp_endpoint *ep, 4630 const struct sctp_association *asoc, 4631 const sctp_subtype_t type, 4632 void *arg, 4633 sctp_cmd_seq_t *commands) 4634 { 4635 struct sctp_chunk *repl = NULL; 4636 struct sctp_bind_addr *bp; 4637 int attempts = asoc->init_err_counter + 1; 4638 4639 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 4640 4641 if (attempts < asoc->max_init_attempts) { 4642 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 4643 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 4644 if (!repl) 4645 return SCTP_DISPOSITION_NOMEM; 4646 4647 /* Choose transport for INIT. */ 4648 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4649 SCTP_CHUNK(repl)); 4650 4651 /* Issue a sideeffect to do the needed accounting. */ 4652 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 4653 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4654 4655 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4656 } else { 4657 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 4658 " max_init_attempts: %d\n", 4659 attempts, asoc->max_init_attempts); 4660 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4661 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4662 return SCTP_DISPOSITION_DELETE_TCB; 4663 } 4664 4665 return SCTP_DISPOSITION_CONSUME; 4666 } 4667 4668 /* 4669 * sctp_sf_t1_cookie_timer_expire 4670 * 4671 * Section: 4 Note: 2 4672 * Verification Tag: 4673 * Inputs 4674 * (endpoint, asoc) 4675 * 4676 * RFC 2960 Section 4 Notes 4677 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 4678 * COOKIE ECHO and re-start the T1-cookie timer without changing 4679 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 4680 * After that, the endpoint MUST abort the initialization process and 4681 * report the error to SCTP user. 4682 * 4683 * Outputs 4684 * (timers, events) 4685 * 4686 */ 4687 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(const struct sctp_endpoint *ep, 4688 const struct sctp_association *asoc, 4689 const sctp_subtype_t type, 4690 void *arg, 4691 sctp_cmd_seq_t *commands) 4692 { 4693 struct sctp_chunk *repl = NULL; 4694 int attempts = asoc->init_err_counter + 1; 4695 4696 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 4697 4698 if (attempts < asoc->max_init_attempts) { 4699 repl = sctp_make_cookie_echo(asoc, NULL); 4700 if (!repl) 4701 return SCTP_DISPOSITION_NOMEM; 4702 4703 /* Issue a sideeffect to do the needed accounting. */ 4704 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 4705 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 4706 4707 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4708 } else { 4709 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4710 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4711 return SCTP_DISPOSITION_DELETE_TCB; 4712 } 4713 4714 return SCTP_DISPOSITION_CONSUME; 4715 } 4716 4717 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 4718 * with the updated last sequential TSN received from its peer. 4719 * 4720 * An endpoint should limit the number of retransmissions of the 4721 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 4722 * If this threshold is exceeded the endpoint should destroy the TCB and 4723 * MUST report the peer endpoint unreachable to the upper layer (and 4724 * thus the association enters the CLOSED state). The reception of any 4725 * packet from its peer (i.e. as the peer sends all of its queued DATA 4726 * chunks) should clear the endpoint's retransmission count and restart 4727 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 4728 * all of its queued DATA chunks that have not yet been sent. 4729 */ 4730 sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, 4731 const struct sctp_association *asoc, 4732 const sctp_subtype_t type, 4733 void *arg, 4734 sctp_cmd_seq_t *commands) 4735 { 4736 struct sctp_chunk *reply = NULL; 4737 4738 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 4739 if (asoc->overall_error_count >= asoc->max_retrans) { 4740 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 4741 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4742 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4743 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4744 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 4745 return SCTP_DISPOSITION_DELETE_TCB; 4746 } 4747 4748 switch (asoc->state) { 4749 case SCTP_STATE_SHUTDOWN_SENT: 4750 reply = sctp_make_shutdown(asoc, NULL); 4751 break; 4752 4753 case SCTP_STATE_SHUTDOWN_ACK_SENT: 4754 reply = sctp_make_shutdown_ack(asoc, NULL); 4755 break; 4756 4757 default: 4758 BUG(); 4759 break; 4760 }; 4761 4762 if (!reply) 4763 goto nomem; 4764 4765 /* Do some failure management (Section 8.2). */ 4766 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 4767 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 4768 4769 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 4770 * the T2-shutdown timer. 4771 */ 4772 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 4773 4774 /* Restart the T2-shutdown timer. */ 4775 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4776 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4777 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4778 return SCTP_DISPOSITION_CONSUME; 4779 4780 nomem: 4781 return SCTP_DISPOSITION_NOMEM; 4782 } 4783 4784 /* 4785 * ADDIP Section 4.1 ASCONF CHunk Procedures 4786 * If the T4 RTO timer expires the endpoint should do B1 to B5 4787 */ 4788 sctp_disposition_t sctp_sf_t4_timer_expire( 4789 const struct sctp_endpoint *ep, 4790 const struct sctp_association *asoc, 4791 const sctp_subtype_t type, 4792 void *arg, 4793 sctp_cmd_seq_t *commands) 4794 { 4795 struct sctp_chunk *chunk = asoc->addip_last_asconf; 4796 struct sctp_transport *transport = chunk->transport; 4797 4798 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 4799 * detection on the appropriate destination address as defined in 4800 * RFC2960 [5] section 8.1 and 8.2. 4801 */ 4802 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 4803 4804 /* Reconfig T4 timer and transport. */ 4805 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 4806 4807 /* ADDIP 4.1 B2) Increment the association error counters and perform 4808 * endpoint failure detection on the association as defined in 4809 * RFC2960 [5] section 8.1 and 8.2. 4810 * association error counter is incremented in SCTP_CMD_STRIKE. 4811 */ 4812 if (asoc->overall_error_count >= asoc->max_retrans) { 4813 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4814 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4815 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4816 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4817 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 4818 SCTP_INC_STATS(SCTP_MIB_CURRESTAB); 4819 return SCTP_DISPOSITION_ABORT; 4820 } 4821 4822 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 4823 * the ASCONF chunk was sent by doubling the RTO timer value. 4824 * This is done in SCTP_CMD_STRIKE. 4825 */ 4826 4827 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 4828 * choose an alternate destination address (please refer to RFC2960 4829 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 4830 * chunk, it MUST be the same (including its serial number) as the last 4831 * ASCONF sent. 4832 */ 4833 sctp_chunk_hold(asoc->addip_last_asconf); 4834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4835 SCTP_CHUNK(asoc->addip_last_asconf)); 4836 4837 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 4838 * destination is selected, then the RTO used will be that of the new 4839 * destination address. 4840 */ 4841 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4842 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4843 4844 return SCTP_DISPOSITION_CONSUME; 4845 } 4846 4847 /* sctpimpguide-05 Section 2.12.2 4848 * The sender of the SHUTDOWN MAY also start an overall guard timer 4849 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4850 * At the expiration of this timer the sender SHOULD abort the association 4851 * by sending an ABORT chunk. 4852 */ 4853 sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, 4854 const struct sctp_association *asoc, 4855 const sctp_subtype_t type, 4856 void *arg, 4857 sctp_cmd_seq_t *commands) 4858 { 4859 struct sctp_chunk *reply = NULL; 4860 4861 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 4862 4863 reply = sctp_make_abort(asoc, NULL, 0); 4864 if (!reply) 4865 goto nomem; 4866 4867 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 4868 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4869 SCTP_U32(SCTP_ERROR_NO_ERROR)); 4870 4871 return SCTP_DISPOSITION_DELETE_TCB; 4872 nomem: 4873 return SCTP_DISPOSITION_NOMEM; 4874 } 4875 4876 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 4877 * the association is automatically closed by starting the shutdown process. 4878 * The work that needs to be done is same as when SHUTDOWN is initiated by 4879 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 4880 */ 4881 sctp_disposition_t sctp_sf_autoclose_timer_expire( 4882 const struct sctp_endpoint *ep, 4883 const struct sctp_association *asoc, 4884 const sctp_subtype_t type, 4885 void *arg, 4886 sctp_cmd_seq_t *commands) 4887 { 4888 int disposition; 4889 4890 /* From 9.2 Shutdown of an Association 4891 * Upon receipt of the SHUTDOWN primitive from its upper 4892 * layer, the endpoint enters SHUTDOWN-PENDING state and 4893 * remains there until all outstanding data has been 4894 * acknowledged by its peer. The endpoint accepts no new data 4895 * from its upper layer, but retransmits data to the far end 4896 * if necessary to fill gaps. 4897 */ 4898 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4899 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4900 4901 /* sctpimpguide-05 Section 2.12.2 4902 * The sender of the SHUTDOWN MAY also start an overall guard timer 4903 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 4904 */ 4905 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4906 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 4907 disposition = SCTP_DISPOSITION_CONSUME; 4908 if (sctp_outq_is_empty(&asoc->outqueue)) { 4909 disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, 4910 arg, commands); 4911 } 4912 return disposition; 4913 } 4914 4915 /***************************************************************************** 4916 * These are sa state functions which could apply to all types of events. 4917 ****************************************************************************/ 4918 4919 /* 4920 * This table entry is not implemented. 4921 * 4922 * Inputs 4923 * (endpoint, asoc, chunk) 4924 * 4925 * The return value is the disposition of the chunk. 4926 */ 4927 sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, 4928 const struct sctp_association *asoc, 4929 const sctp_subtype_t type, 4930 void *arg, 4931 sctp_cmd_seq_t *commands) 4932 { 4933 return SCTP_DISPOSITION_NOT_IMPL; 4934 } 4935 4936 /* 4937 * This table entry represents a bug. 4938 * 4939 * Inputs 4940 * (endpoint, asoc, chunk) 4941 * 4942 * The return value is the disposition of the chunk. 4943 */ 4944 sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, 4945 const struct sctp_association *asoc, 4946 const sctp_subtype_t type, 4947 void *arg, 4948 sctp_cmd_seq_t *commands) 4949 { 4950 return SCTP_DISPOSITION_BUG; 4951 } 4952 4953 /* 4954 * This table entry represents the firing of a timer in the wrong state. 4955 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 4956 * when the association is in the wrong state. This event should 4957 * be ignored, so as to prevent any rearming of the timer. 4958 * 4959 * Inputs 4960 * (endpoint, asoc, chunk) 4961 * 4962 * The return value is the disposition of the chunk. 4963 */ 4964 sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, 4965 const struct sctp_association *asoc, 4966 const sctp_subtype_t type, 4967 void *arg, 4968 sctp_cmd_seq_t *commands) 4969 { 4970 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 4971 return SCTP_DISPOSITION_CONSUME; 4972 } 4973 4974 /******************************************************************** 4975 * 2nd Level Abstractions 4976 ********************************************************************/ 4977 4978 /* Pull the SACK chunk based on the SACK header. */ 4979 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 4980 { 4981 struct sctp_sackhdr *sack; 4982 unsigned int len; 4983 __u16 num_blocks; 4984 __u16 num_dup_tsns; 4985 4986 /* Protect ourselves from reading too far into 4987 * the skb from a bogus sender. 4988 */ 4989 sack = (struct sctp_sackhdr *) chunk->skb->data; 4990 4991 num_blocks = ntohs(sack->num_gap_ack_blocks); 4992 num_dup_tsns = ntohs(sack->num_dup_tsns); 4993 len = sizeof(struct sctp_sackhdr); 4994 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 4995 if (len > chunk->skb->len) 4996 return NULL; 4997 4998 skb_pull(chunk->skb, len); 4999 5000 return sack; 5001 } 5002 5003 /* Create an ABORT packet to be sent as a response, with the specified 5004 * error causes. 5005 */ 5006 static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 5007 const struct sctp_association *asoc, 5008 struct sctp_chunk *chunk, 5009 const void *payload, 5010 size_t paylen) 5011 { 5012 struct sctp_packet *packet; 5013 struct sctp_chunk *abort; 5014 5015 packet = sctp_ootb_pkt_new(asoc, chunk); 5016 5017 if (packet) { 5018 /* Make an ABORT. 5019 * The T bit will be set if the asoc is NULL. 5020 */ 5021 abort = sctp_make_abort(asoc, chunk, paylen); 5022 if (!abort) { 5023 sctp_ootb_pkt_free(packet); 5024 return NULL; 5025 } 5026 5027 /* Reflect vtag if T-Bit is set */ 5028 if (sctp_test_T_bit(abort)) 5029 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5030 5031 /* Add specified error causes, i.e., payload, to the 5032 * end of the chunk. 5033 */ 5034 sctp_addto_chunk(abort, paylen, payload); 5035 5036 /* Set the skb to the belonging sock for accounting. */ 5037 abort->skb->sk = ep->base.sk; 5038 5039 sctp_packet_append_chunk(packet, abort); 5040 5041 } 5042 5043 return packet; 5044 } 5045 5046 /* Allocate a packet for responding in the OOTB conditions. */ 5047 static struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, 5048 const struct sctp_chunk *chunk) 5049 { 5050 struct sctp_packet *packet; 5051 struct sctp_transport *transport; 5052 __u16 sport; 5053 __u16 dport; 5054 __u32 vtag; 5055 5056 /* Get the source and destination port from the inbound packet. */ 5057 sport = ntohs(chunk->sctp_hdr->dest); 5058 dport = ntohs(chunk->sctp_hdr->source); 5059 5060 /* The V-tag is going to be the same as the inbound packet if no 5061 * association exists, otherwise, use the peer's vtag. 5062 */ 5063 if (asoc) { 5064 vtag = asoc->peer.i.init_tag; 5065 } else { 5066 /* Special case the INIT and stale COOKIE_ECHO as there is no 5067 * vtag yet. 5068 */ 5069 switch(chunk->chunk_hdr->type) { 5070 case SCTP_CID_INIT: 5071 { 5072 sctp_init_chunk_t *init; 5073 5074 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 5075 vtag = ntohl(init->init_hdr.init_tag); 5076 break; 5077 } 5078 default: 5079 vtag = ntohl(chunk->sctp_hdr->vtag); 5080 break; 5081 } 5082 } 5083 5084 /* Make a transport for the bucket, Eliza... */ 5085 transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); 5086 if (!transport) 5087 goto nomem; 5088 5089 /* Cache a route for the transport with the chunk's destination as 5090 * the source address. 5091 */ 5092 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 5093 sctp_sk(sctp_get_ctl_sock())); 5094 5095 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 5096 packet = sctp_packet_config(packet, vtag, 0); 5097 5098 return packet; 5099 5100 nomem: 5101 return NULL; 5102 } 5103 5104 /* Free the packet allocated earlier for responding in the OOTB condition. */ 5105 void sctp_ootb_pkt_free(struct sctp_packet *packet) 5106 { 5107 sctp_transport_free(packet->transport); 5108 } 5109 5110 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 5111 static void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, 5112 const struct sctp_association *asoc, 5113 const struct sctp_chunk *chunk, 5114 sctp_cmd_seq_t *commands, 5115 struct sctp_chunk *err_chunk) 5116 { 5117 struct sctp_packet *packet; 5118 5119 if (err_chunk) { 5120 packet = sctp_ootb_pkt_new(asoc, chunk); 5121 if (packet) { 5122 struct sctp_signed_cookie *cookie; 5123 5124 /* Override the OOTB vtag from the cookie. */ 5125 cookie = chunk->subh.cookie_hdr; 5126 packet->vtag = cookie->c.peer_vtag; 5127 5128 /* Set the skb to the belonging sock for accounting. */ 5129 err_chunk->skb->sk = ep->base.sk; 5130 sctp_packet_append_chunk(packet, err_chunk); 5131 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 5132 SCTP_PACKET(packet)); 5133 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 5134 } else 5135 sctp_chunk_free (err_chunk); 5136 } 5137 } 5138 5139 5140 /* Process a data chunk */ 5141 static int sctp_eat_data(const struct sctp_association *asoc, 5142 struct sctp_chunk *chunk, 5143 sctp_cmd_seq_t *commands) 5144 { 5145 sctp_datahdr_t *data_hdr; 5146 struct sctp_chunk *err; 5147 size_t datalen; 5148 sctp_verb_t deliver; 5149 int tmp; 5150 __u32 tsn; 5151 5152 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 5153 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 5154 5155 tsn = ntohl(data_hdr->tsn); 5156 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 5157 5158 /* ASSERT: Now skb->data is really the user data. */ 5159 5160 /* Process ECN based congestion. 5161 * 5162 * Since the chunk structure is reused for all chunks within 5163 * a packet, we use ecn_ce_done to track if we've already 5164 * done CE processing for this packet. 5165 * 5166 * We need to do ECN processing even if we plan to discard the 5167 * chunk later. 5168 */ 5169 5170 if (!chunk->ecn_ce_done) { 5171 struct sctp_af *af; 5172 chunk->ecn_ce_done = 1; 5173 5174 af = sctp_get_af_specific( 5175 ipver2af(chunk->skb->nh.iph->version)); 5176 5177 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 5178 /* Do real work as sideffect. */ 5179 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 5180 SCTP_U32(tsn)); 5181 } 5182 } 5183 5184 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 5185 if (tmp < 0) { 5186 /* The TSN is too high--silently discard the chunk and 5187 * count on it getting retransmitted later. 5188 */ 5189 return SCTP_IERROR_HIGH_TSN; 5190 } else if (tmp > 0) { 5191 /* This is a duplicate. Record it. */ 5192 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 5193 return SCTP_IERROR_DUP_TSN; 5194 } 5195 5196 /* This is a new TSN. */ 5197 5198 /* Discard if there is no room in the receive window. 5199 * Actually, allow a little bit of overflow (up to a MTU). 5200 */ 5201 datalen = ntohs(chunk->chunk_hdr->length); 5202 datalen -= sizeof(sctp_data_chunk_t); 5203 5204 deliver = SCTP_CMD_CHUNK_ULP; 5205 5206 /* Think about partial delivery. */ 5207 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 5208 5209 /* Even if we don't accept this chunk there is 5210 * memory pressure. 5211 */ 5212 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 5213 } 5214 5215 /* Spill over rwnd a little bit. Note: While allowed, this spill over 5216 * seems a bit troublesome in that frag_point varies based on 5217 * PMTU. In cases, such as loopback, this might be a rather 5218 * large spill over. 5219 */ 5220 if (!asoc->rwnd || asoc->rwnd_over || 5221 (datalen > asoc->rwnd + asoc->frag_point)) { 5222 5223 /* If this is the next TSN, consider reneging to make 5224 * room. Note: Playing nice with a confused sender. A 5225 * malicious sender can still eat up all our buffer 5226 * space and in the future we may want to detect and 5227 * do more drastic reneging. 5228 */ 5229 if (sctp_tsnmap_has_gap(&asoc->peer.tsn_map) && 5230 (sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1) == tsn) { 5231 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 5232 deliver = SCTP_CMD_RENEGE; 5233 } else { 5234 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 5235 "rwnd: %d\n", tsn, datalen, 5236 asoc->rwnd); 5237 return SCTP_IERROR_IGNORE_TSN; 5238 } 5239 } 5240 5241 /* 5242 * Section 3.3.10.9 No User Data (9) 5243 * 5244 * Cause of error 5245 * --------------- 5246 * No User Data: This error cause is returned to the originator of a 5247 * DATA chunk if a received DATA chunk has no user data. 5248 */ 5249 if (unlikely(0 == datalen)) { 5250 err = sctp_make_abort_no_data(asoc, chunk, tsn); 5251 if (err) { 5252 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5253 SCTP_CHUNK(err)); 5254 } 5255 /* We are going to ABORT, so we might as well stop 5256 * processing the rest of the chunks in the packet. 5257 */ 5258 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 5259 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5260 SCTP_U32(SCTP_ERROR_NO_DATA)); 5261 SCTP_INC_STATS(SCTP_MIB_ABORTEDS); 5262 SCTP_DEC_STATS(SCTP_MIB_CURRESTAB); 5263 return SCTP_IERROR_NO_DATA; 5264 } 5265 5266 /* If definately accepting the DATA chunk, record its TSN, otherwise 5267 * wait for renege processing. 5268 */ 5269 if (SCTP_CMD_CHUNK_ULP == deliver) 5270 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 5271 5272 /* Note: Some chunks may get overcounted (if we drop) or overcounted 5273 * if we renege and the chunk arrives again. 5274 */ 5275 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 5276 SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS); 5277 else 5278 SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS); 5279 5280 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 5281 * 5282 * If an endpoint receive a DATA chunk with an invalid stream 5283 * identifier, it shall acknowledge the reception of the DATA chunk 5284 * following the normal procedure, immediately send an ERROR chunk 5285 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 5286 * and discard the DATA chunk. 5287 */ 5288 if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { 5289 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 5290 &data_hdr->stream, 5291 sizeof(data_hdr->stream)); 5292 if (err) 5293 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5294 SCTP_CHUNK(err)); 5295 return SCTP_IERROR_BAD_STREAM; 5296 } 5297 5298 /* Send the data up to the user. Note: Schedule the 5299 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 5300 * chunk needs the updated rwnd. 5301 */ 5302 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 5303 5304 return SCTP_IERROR_NO_ERROR; 5305 } 5306