1 /* SCTP kernel 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 is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, see 26 * <http://www.gnu.org/licenses/>. 27 * 28 * Please send any bug reports or fixes you make to the 29 * email address(es): 30 * lksctp developers <linux-sctp@vger.kernel.org> 31 * 32 * Written or modified by: 33 * La Monte H.P. Yarroll <piggy@acm.org> 34 * Karl Knutson <karl@athena.chicago.il.us> 35 * Mathew Kotowsky <kotowsky@sctp.org> 36 * Sridhar Samudrala <samudrala@us.ibm.com> 37 * Jon Grimm <jgrimm@us.ibm.com> 38 * Hui Huang <hui.huang@nokia.com> 39 * Dajiang Zhang <dajiang.zhang@nokia.com> 40 * Daisy Chang <daisyc@us.ibm.com> 41 * Ardelle Fan <ardelle.fan@intel.com> 42 * Ryan Layer <rmlayer@us.ibm.com> 43 * Kevin Gao <kevin.gao@intel.com> 44 */ 45 46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 47 48 #include <linux/types.h> 49 #include <linux/kernel.h> 50 #include <linux/ip.h> 51 #include <linux/ipv6.h> 52 #include <linux/net.h> 53 #include <linux/inet.h> 54 #include <linux/slab.h> 55 #include <net/sock.h> 56 #include <net/inet_ecn.h> 57 #include <linux/skbuff.h> 58 #include <net/sctp/sctp.h> 59 #include <net/sctp/sm.h> 60 #include <net/sctp/structs.h> 61 62 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 63 const struct sctp_endpoint *ep, 64 const struct sctp_association *asoc, 65 struct sctp_chunk *chunk, 66 const void *payload, 67 size_t paylen); 68 static int sctp_eat_data(const struct sctp_association *asoc, 69 struct sctp_chunk *chunk, 70 sctp_cmd_seq_t *commands); 71 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 72 const struct sctp_association *asoc, 73 const struct sctp_chunk *chunk); 74 static void sctp_send_stale_cookie_err(struct net *net, 75 const struct sctp_endpoint *ep, 76 const struct sctp_association *asoc, 77 const struct sctp_chunk *chunk, 78 sctp_cmd_seq_t *commands, 79 struct sctp_chunk *err_chunk); 80 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 81 const struct sctp_endpoint *ep, 82 const struct sctp_association *asoc, 83 const sctp_subtype_t type, 84 void *arg, 85 sctp_cmd_seq_t *commands); 86 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const sctp_subtype_t type, 90 void *arg, 91 sctp_cmd_seq_t *commands); 92 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 93 const struct sctp_endpoint *ep, 94 const struct sctp_association *asoc, 95 const sctp_subtype_t type, 96 void *arg, 97 sctp_cmd_seq_t *commands); 98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 99 100 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 101 sctp_cmd_seq_t *commands, 102 __be16 error, int sk_err, 103 const struct sctp_association *asoc, 104 struct sctp_transport *transport); 105 106 static sctp_disposition_t sctp_sf_abort_violation( 107 struct net *net, 108 const struct sctp_endpoint *ep, 109 const struct sctp_association *asoc, 110 void *arg, 111 sctp_cmd_seq_t *commands, 112 const __u8 *payload, 113 const size_t paylen); 114 115 static sctp_disposition_t sctp_sf_violation_chunklen( 116 struct net *net, 117 const struct sctp_endpoint *ep, 118 const struct sctp_association *asoc, 119 const sctp_subtype_t type, 120 void *arg, 121 sctp_cmd_seq_t *commands); 122 123 static sctp_disposition_t sctp_sf_violation_paramlen( 124 struct net *net, 125 const struct sctp_endpoint *ep, 126 const struct sctp_association *asoc, 127 const sctp_subtype_t type, 128 void *arg, void *ext, 129 sctp_cmd_seq_t *commands); 130 131 static sctp_disposition_t sctp_sf_violation_ctsn( 132 struct net *net, 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const sctp_subtype_t type, 136 void *arg, 137 sctp_cmd_seq_t *commands); 138 139 static sctp_disposition_t sctp_sf_violation_chunk( 140 struct net *net, 141 const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const sctp_subtype_t type, 144 void *arg, 145 sctp_cmd_seq_t *commands); 146 147 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 148 const struct sctp_endpoint *ep, 149 const struct sctp_association *asoc, 150 const sctp_subtype_t type, 151 struct sctp_chunk *chunk); 152 153 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 154 const struct sctp_endpoint *ep, 155 const struct sctp_association *asoc, 156 const sctp_subtype_t type, 157 void *arg, 158 sctp_cmd_seq_t *commands); 159 160 /* Small helper function that checks if the chunk length 161 * is of the appropriate length. The 'required_length' argument 162 * is set to be the size of a specific chunk we are testing. 163 * Return Values: true = Valid length 164 * false = Invalid length 165 * 166 */ 167 static inline bool 168 sctp_chunk_length_valid(struct sctp_chunk *chunk, __u16 required_length) 169 { 170 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 171 172 /* Previously already marked? */ 173 if (unlikely(chunk->pdiscard)) 174 return false; 175 if (unlikely(chunk_length < required_length)) 176 return false; 177 178 return true; 179 } 180 181 /********************************************************** 182 * These are the state functions for handling chunk events. 183 **********************************************************/ 184 185 /* 186 * Process the final SHUTDOWN COMPLETE. 187 * 188 * Section: 4 (C) (diagram), 9.2 189 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 190 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 191 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 192 * should stop the T2-shutdown timer and remove all knowledge of the 193 * association (and thus the association enters the CLOSED state). 194 * 195 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 196 * C) Rules for packet carrying SHUTDOWN COMPLETE: 197 * ... 198 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 199 * if the Verification Tag field of the packet matches its own tag and 200 * the T bit is not set 201 * OR 202 * it is set to its peer's tag and the T bit is set in the Chunk 203 * Flags. 204 * Otherwise, the receiver MUST silently discard the packet 205 * and take no further action. An endpoint MUST ignore the 206 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 207 * 208 * Inputs 209 * (endpoint, asoc, chunk) 210 * 211 * Outputs 212 * (asoc, reply_msg, msg_up, timers, counters) 213 * 214 * The return value is the disposition of the chunk. 215 */ 216 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 217 const struct sctp_endpoint *ep, 218 const struct sctp_association *asoc, 219 const sctp_subtype_t type, 220 void *arg, 221 sctp_cmd_seq_t *commands) 222 { 223 struct sctp_chunk *chunk = arg; 224 struct sctp_ulpevent *ev; 225 226 if (!sctp_vtag_verify_either(chunk, asoc)) 227 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 228 229 /* RFC 2960 6.10 Bundling 230 * 231 * An endpoint MUST NOT bundle INIT, INIT ACK or 232 * SHUTDOWN COMPLETE with any other chunks. 233 */ 234 if (!chunk->singleton) 235 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 236 237 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 238 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 239 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 240 commands); 241 242 /* RFC 2960 10.2 SCTP-to-ULP 243 * 244 * H) SHUTDOWN COMPLETE notification 245 * 246 * When SCTP completes the shutdown procedures (section 9.2) this 247 * notification is passed to the upper layer. 248 */ 249 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 250 0, 0, 0, NULL, GFP_ATOMIC); 251 if (ev) 252 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 253 SCTP_ULPEVENT(ev)); 254 255 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 256 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 257 * not the chunk should be discarded. If the endpoint is in 258 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 259 * T2-shutdown timer and remove all knowledge of the 260 * association (and thus the association enters the CLOSED 261 * state). 262 */ 263 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 264 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 265 266 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 267 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 268 269 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 270 SCTP_STATE(SCTP_STATE_CLOSED)); 271 272 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 273 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 274 275 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 276 277 return SCTP_DISPOSITION_DELETE_TCB; 278 } 279 280 /* 281 * Respond to a normal INIT chunk. 282 * We are the side that is being asked for an association. 283 * 284 * Section: 5.1 Normal Establishment of an Association, B 285 * B) "Z" shall respond immediately with an INIT ACK chunk. The 286 * destination IP address of the INIT ACK MUST be set to the source 287 * IP address of the INIT to which this INIT ACK is responding. In 288 * the response, besides filling in other parameters, "Z" must set the 289 * Verification Tag field to Tag_A, and also provide its own 290 * Verification Tag (Tag_Z) in the Initiate Tag field. 291 * 292 * Verification Tag: Must be 0. 293 * 294 * Inputs 295 * (endpoint, asoc, chunk) 296 * 297 * Outputs 298 * (asoc, reply_msg, msg_up, timers, counters) 299 * 300 * The return value is the disposition of the chunk. 301 */ 302 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 303 const struct sctp_endpoint *ep, 304 const struct sctp_association *asoc, 305 const sctp_subtype_t type, 306 void *arg, 307 sctp_cmd_seq_t *commands) 308 { 309 struct sctp_chunk *chunk = arg; 310 struct sctp_chunk *repl; 311 struct sctp_association *new_asoc; 312 struct sctp_chunk *err_chunk; 313 struct sctp_packet *packet; 314 sctp_unrecognized_param_t *unk_param; 315 int len; 316 317 /* 6.10 Bundling 318 * An endpoint MUST NOT bundle INIT, INIT ACK or 319 * SHUTDOWN COMPLETE with any other chunks. 320 * 321 * IG Section 2.11.2 322 * Furthermore, we require that the receiver of an INIT chunk MUST 323 * enforce these rules by silently discarding an arriving packet 324 * with an INIT chunk that is bundled with other chunks. 325 */ 326 if (!chunk->singleton) 327 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 328 329 /* If the packet is an OOTB packet which is temporarily on the 330 * control endpoint, respond with an ABORT. 331 */ 332 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 333 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 334 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 335 } 336 337 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 338 * Tag. 339 */ 340 if (chunk->sctp_hdr->vtag != 0) 341 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 342 343 /* Make sure that the INIT chunk has a valid length. 344 * Normally, this would cause an ABORT with a Protocol Violation 345 * error, but since we don't have an association, we'll 346 * just discard the packet. 347 */ 348 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 349 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 350 351 /* If the INIT is coming toward a closing socket, we'll send back 352 * and ABORT. Essentially, this catches the race of INIT being 353 * backloged to the socket at the same time as the user isses close(). 354 * Since the socket and all its associations are going away, we 355 * can treat this OOTB 356 */ 357 if (sctp_sstate(ep->base.sk, CLOSING)) 358 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 359 360 /* Verify the INIT chunk before processing it. */ 361 err_chunk = NULL; 362 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 363 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 364 &err_chunk)) { 365 /* This chunk contains fatal error. It is to be discarded. 366 * Send an ABORT, with causes if there is any. 367 */ 368 if (err_chunk) { 369 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 370 (__u8 *)(err_chunk->chunk_hdr) + 371 sizeof(sctp_chunkhdr_t), 372 ntohs(err_chunk->chunk_hdr->length) - 373 sizeof(sctp_chunkhdr_t)); 374 375 sctp_chunk_free(err_chunk); 376 377 if (packet) { 378 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 379 SCTP_PACKET(packet)); 380 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 381 return SCTP_DISPOSITION_CONSUME; 382 } else { 383 return SCTP_DISPOSITION_NOMEM; 384 } 385 } else { 386 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 387 commands); 388 } 389 } 390 391 /* Grab the INIT header. */ 392 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 393 394 /* Tag the variable length parameters. */ 395 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 396 397 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 398 if (!new_asoc) 399 goto nomem; 400 401 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 402 sctp_scope(sctp_source(chunk)), 403 GFP_ATOMIC) < 0) 404 goto nomem_init; 405 406 /* The call, sctp_process_init(), can fail on memory allocation. */ 407 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 408 (sctp_init_chunk_t *)chunk->chunk_hdr, 409 GFP_ATOMIC)) 410 goto nomem_init; 411 412 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 413 414 /* If there are errors need to be reported for unknown parameters, 415 * make sure to reserve enough room in the INIT ACK for them. 416 */ 417 len = 0; 418 if (err_chunk) 419 len = ntohs(err_chunk->chunk_hdr->length) - 420 sizeof(sctp_chunkhdr_t); 421 422 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 423 if (!repl) 424 goto nomem_init; 425 426 /* If there are errors need to be reported for unknown parameters, 427 * include them in the outgoing INIT ACK as "Unrecognized parameter" 428 * parameter. 429 */ 430 if (err_chunk) { 431 /* Get the "Unrecognized parameter" parameter(s) out of the 432 * ERROR chunk generated by sctp_verify_init(). Since the 433 * error cause code for "unknown parameter" and the 434 * "Unrecognized parameter" type is the same, we can 435 * construct the parameters in INIT ACK by copying the 436 * ERROR causes over. 437 */ 438 unk_param = (sctp_unrecognized_param_t *) 439 ((__u8 *)(err_chunk->chunk_hdr) + 440 sizeof(sctp_chunkhdr_t)); 441 /* Replace the cause code with the "Unrecognized parameter" 442 * parameter type. 443 */ 444 sctp_addto_chunk(repl, len, unk_param); 445 sctp_chunk_free(err_chunk); 446 } 447 448 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 449 450 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 451 452 /* 453 * Note: After sending out INIT ACK with the State Cookie parameter, 454 * "Z" MUST NOT allocate any resources, nor keep any states for the 455 * new association. Otherwise, "Z" will be vulnerable to resource 456 * attacks. 457 */ 458 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 459 460 return SCTP_DISPOSITION_DELETE_TCB; 461 462 nomem_init: 463 sctp_association_free(new_asoc); 464 nomem: 465 if (err_chunk) 466 sctp_chunk_free(err_chunk); 467 return SCTP_DISPOSITION_NOMEM; 468 } 469 470 /* 471 * Respond to a normal INIT ACK chunk. 472 * We are the side that is initiating the association. 473 * 474 * Section: 5.1 Normal Establishment of an Association, C 475 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 476 * timer and leave COOKIE-WAIT state. "A" shall then send the State 477 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 478 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 479 * 480 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 481 * DATA chunks, but it MUST be the first chunk in the packet and 482 * until the COOKIE ACK is returned the sender MUST NOT send any 483 * other packets to the peer. 484 * 485 * Verification Tag: 3.3.3 486 * If the value of the Initiate Tag in a received INIT ACK chunk is 487 * found to be 0, the receiver MUST treat it as an error and close the 488 * association by transmitting an ABORT. 489 * 490 * Inputs 491 * (endpoint, asoc, chunk) 492 * 493 * Outputs 494 * (asoc, reply_msg, msg_up, timers, counters) 495 * 496 * The return value is the disposition of the chunk. 497 */ 498 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 499 const struct sctp_endpoint *ep, 500 const struct sctp_association *asoc, 501 const sctp_subtype_t type, 502 void *arg, 503 sctp_cmd_seq_t *commands) 504 { 505 struct sctp_chunk *chunk = arg; 506 sctp_init_chunk_t *initchunk; 507 struct sctp_chunk *err_chunk; 508 struct sctp_packet *packet; 509 510 if (!sctp_vtag_verify(chunk, asoc)) 511 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 512 513 /* 6.10 Bundling 514 * An endpoint MUST NOT bundle INIT, INIT ACK or 515 * SHUTDOWN COMPLETE with any other chunks. 516 */ 517 if (!chunk->singleton) 518 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 519 520 /* Make sure that the INIT-ACK chunk has a valid length */ 521 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 522 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 523 commands); 524 /* Grab the INIT header. */ 525 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 526 527 /* Verify the INIT chunk before processing it. */ 528 err_chunk = NULL; 529 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 530 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 531 &err_chunk)) { 532 533 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 534 535 /* This chunk contains fatal error. It is to be discarded. 536 * Send an ABORT, with causes. If there are no causes, 537 * then there wasn't enough memory. Just terminate 538 * the association. 539 */ 540 if (err_chunk) { 541 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 542 (__u8 *)(err_chunk->chunk_hdr) + 543 sizeof(sctp_chunkhdr_t), 544 ntohs(err_chunk->chunk_hdr->length) - 545 sizeof(sctp_chunkhdr_t)); 546 547 sctp_chunk_free(err_chunk); 548 549 if (packet) { 550 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 551 SCTP_PACKET(packet)); 552 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 553 error = SCTP_ERROR_INV_PARAM; 554 } 555 } 556 557 /* SCTP-AUTH, Section 6.3: 558 * It should be noted that if the receiver wants to tear 559 * down an association in an authenticated way only, the 560 * handling of malformed packets should not result in 561 * tearing down the association. 562 * 563 * This means that if we only want to abort associations 564 * in an authenticated way (i.e AUTH+ABORT), then we 565 * can't destroy this association just because the packet 566 * was malformed. 567 */ 568 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 569 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 570 571 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 572 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 573 asoc, chunk->transport); 574 } 575 576 /* Tag the variable length parameters. Note that we never 577 * convert the parameters in an INIT chunk. 578 */ 579 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 580 581 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 582 583 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 584 SCTP_PEER_INIT(initchunk)); 585 586 /* Reset init error count upon receipt of INIT-ACK. */ 587 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 588 589 /* 5.1 C) "A" shall stop the T1-init timer and leave 590 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 591 * timer, and enter the COOKIE-ECHOED state. 592 */ 593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 595 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 596 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 597 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 598 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 599 600 /* SCTP-AUTH: genereate the assocition shared keys so that 601 * we can potentially signe the COOKIE-ECHO. 602 */ 603 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 604 605 /* 5.1 C) "A" shall then send the State Cookie received in the 606 * INIT ACK chunk in a COOKIE ECHO chunk, ... 607 */ 608 /* If there is any errors to report, send the ERROR chunk generated 609 * for unknown parameters as well. 610 */ 611 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 612 SCTP_CHUNK(err_chunk)); 613 614 return SCTP_DISPOSITION_CONSUME; 615 } 616 617 /* 618 * Respond to a normal COOKIE ECHO chunk. 619 * We are the side that is being asked for an association. 620 * 621 * Section: 5.1 Normal Establishment of an Association, D 622 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 623 * with a COOKIE ACK chunk after building a TCB and moving to 624 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 625 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 626 * chunk MUST be the first chunk in the packet. 627 * 628 * IMPLEMENTATION NOTE: An implementation may choose to send the 629 * Communication Up notification to the SCTP user upon reception 630 * of a valid COOKIE ECHO chunk. 631 * 632 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 633 * D) Rules for packet carrying a COOKIE ECHO 634 * 635 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 636 * Initial Tag received in the INIT ACK. 637 * 638 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 639 * 640 * Inputs 641 * (endpoint, asoc, chunk) 642 * 643 * Outputs 644 * (asoc, reply_msg, msg_up, timers, counters) 645 * 646 * The return value is the disposition of the chunk. 647 */ 648 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 649 const struct sctp_endpoint *ep, 650 const struct sctp_association *asoc, 651 const sctp_subtype_t type, void *arg, 652 sctp_cmd_seq_t *commands) 653 { 654 struct sctp_chunk *chunk = arg; 655 struct sctp_association *new_asoc; 656 sctp_init_chunk_t *peer_init; 657 struct sctp_chunk *repl; 658 struct sctp_ulpevent *ev, *ai_ev = NULL; 659 int error = 0; 660 struct sctp_chunk *err_chk_p; 661 struct sock *sk; 662 663 /* If the packet is an OOTB packet which is temporarily on the 664 * control endpoint, respond with an ABORT. 665 */ 666 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 667 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 668 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 669 } 670 671 /* Make sure that the COOKIE_ECHO chunk has a valid length. 672 * In this case, we check that we have enough for at least a 673 * chunk header. More detailed verification is done 674 * in sctp_unpack_cookie(). 675 */ 676 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 677 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 678 679 /* If the endpoint is not listening or if the number of associations 680 * on the TCP-style socket exceed the max backlog, respond with an 681 * ABORT. 682 */ 683 sk = ep->base.sk; 684 if (!sctp_sstate(sk, LISTENING) || 685 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 686 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 687 688 /* "Decode" the chunk. We have no optional parameters so we 689 * are in good shape. 690 */ 691 chunk->subh.cookie_hdr = 692 (struct sctp_signed_cookie *)chunk->skb->data; 693 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 694 sizeof(sctp_chunkhdr_t))) 695 goto nomem; 696 697 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 698 * "Z" will reply with a COOKIE ACK chunk after building a TCB 699 * and moving to the ESTABLISHED state. 700 */ 701 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 702 &err_chk_p); 703 704 /* FIXME: 705 * If the re-build failed, what is the proper error path 706 * from here? 707 * 708 * [We should abort the association. --piggy] 709 */ 710 if (!new_asoc) { 711 /* FIXME: Several errors are possible. A bad cookie should 712 * be silently discarded, but think about logging it too. 713 */ 714 switch (error) { 715 case -SCTP_IERROR_NOMEM: 716 goto nomem; 717 718 case -SCTP_IERROR_STALE_COOKIE: 719 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 720 err_chk_p); 721 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 722 723 case -SCTP_IERROR_BAD_SIG: 724 default: 725 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 726 } 727 } 728 729 730 /* Delay state machine commands until later. 731 * 732 * Re-build the bind address for the association is done in 733 * the sctp_unpack_cookie() already. 734 */ 735 /* This is a brand-new association, so these are not yet side 736 * effects--it is safe to run them here. 737 */ 738 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 739 740 if (!sctp_process_init(new_asoc, chunk, 741 &chunk->subh.cookie_hdr->c.peer_addr, 742 peer_init, GFP_ATOMIC)) 743 goto nomem_init; 744 745 /* SCTP-AUTH: Now that we've populate required fields in 746 * sctp_process_init, set up the assocaition shared keys as 747 * necessary so that we can potentially authenticate the ACK 748 */ 749 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 750 if (error) 751 goto nomem_init; 752 753 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 754 * is supposed to be authenticated and we have to do delayed 755 * authentication. We've just recreated the association using 756 * the information in the cookie and now it's much easier to 757 * do the authentication. 758 */ 759 if (chunk->auth_chunk) { 760 struct sctp_chunk auth; 761 sctp_ierror_t ret; 762 763 /* Make sure that we and the peer are AUTH capable */ 764 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) { 765 sctp_association_free(new_asoc); 766 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 767 } 768 769 /* set-up our fake chunk so that we can process it */ 770 auth.skb = chunk->auth_chunk; 771 auth.asoc = chunk->asoc; 772 auth.sctp_hdr = chunk->sctp_hdr; 773 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 774 sizeof(sctp_chunkhdr_t)); 775 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 776 auth.transport = chunk->transport; 777 778 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 779 if (ret != SCTP_IERROR_NO_ERROR) { 780 sctp_association_free(new_asoc); 781 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 782 } 783 } 784 785 repl = sctp_make_cookie_ack(new_asoc, chunk); 786 if (!repl) 787 goto nomem_init; 788 789 /* RFC 2960 5.1 Normal Establishment of an Association 790 * 791 * D) IMPLEMENTATION NOTE: An implementation may choose to 792 * send the Communication Up notification to the SCTP user 793 * upon reception of a valid COOKIE ECHO chunk. 794 */ 795 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 796 new_asoc->c.sinit_num_ostreams, 797 new_asoc->c.sinit_max_instreams, 798 NULL, GFP_ATOMIC); 799 if (!ev) 800 goto nomem_ev; 801 802 /* Sockets API Draft Section 5.3.1.6 803 * When a peer sends a Adaptation Layer Indication parameter , SCTP 804 * delivers this notification to inform the application that of the 805 * peers requested adaptation layer. 806 */ 807 if (new_asoc->peer.adaptation_ind) { 808 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 809 GFP_ATOMIC); 810 if (!ai_ev) 811 goto nomem_aiev; 812 } 813 814 /* Add all the state machine commands now since we've created 815 * everything. This way we don't introduce memory corruptions 816 * during side-effect processing and correclty count established 817 * associations. 818 */ 819 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 820 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 821 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 822 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 823 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 824 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 825 826 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 827 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 828 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 829 830 /* This will send the COOKIE ACK */ 831 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 832 833 /* Queue the ASSOC_CHANGE event */ 834 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 835 836 /* Send up the Adaptation Layer Indication event */ 837 if (ai_ev) 838 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 839 SCTP_ULPEVENT(ai_ev)); 840 841 return SCTP_DISPOSITION_CONSUME; 842 843 nomem_aiev: 844 sctp_ulpevent_free(ev); 845 nomem_ev: 846 sctp_chunk_free(repl); 847 nomem_init: 848 sctp_association_free(new_asoc); 849 nomem: 850 return SCTP_DISPOSITION_NOMEM; 851 } 852 853 /* 854 * Respond to a normal COOKIE ACK chunk. 855 * We are the side that is asking for an association. 856 * 857 * RFC 2960 5.1 Normal Establishment of an Association 858 * 859 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 860 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 861 * timer. It may also notify its ULP about the successful 862 * establishment of the association with a Communication Up 863 * notification (see Section 10). 864 * 865 * Verification Tag: 866 * Inputs 867 * (endpoint, asoc, chunk) 868 * 869 * Outputs 870 * (asoc, reply_msg, msg_up, timers, counters) 871 * 872 * The return value is the disposition of the chunk. 873 */ 874 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 875 const struct sctp_endpoint *ep, 876 const struct sctp_association *asoc, 877 const sctp_subtype_t type, void *arg, 878 sctp_cmd_seq_t *commands) 879 { 880 struct sctp_chunk *chunk = arg; 881 struct sctp_ulpevent *ev; 882 883 if (!sctp_vtag_verify(chunk, asoc)) 884 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 885 886 /* Verify that the chunk length for the COOKIE-ACK is OK. 887 * If we don't do this, any bundled chunks may be junked. 888 */ 889 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 890 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 891 commands); 892 893 /* Reset init error count upon receipt of COOKIE-ACK, 894 * to avoid problems with the managemement of this 895 * counter in stale cookie situations when a transition back 896 * from the COOKIE-ECHOED state to the COOKIE-WAIT 897 * state is performed. 898 */ 899 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 900 901 /* RFC 2960 5.1 Normal Establishment of an Association 902 * 903 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 904 * from the COOKIE-ECHOED state to the ESTABLISHED state, 905 * stopping the T1-cookie timer. 906 */ 907 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 908 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 909 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 910 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 911 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 912 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 913 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 914 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 915 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 916 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 917 918 /* It may also notify its ULP about the successful 919 * establishment of the association with a Communication Up 920 * notification (see Section 10). 921 */ 922 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 923 0, asoc->c.sinit_num_ostreams, 924 asoc->c.sinit_max_instreams, 925 NULL, GFP_ATOMIC); 926 927 if (!ev) 928 goto nomem; 929 930 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 931 932 /* Sockets API Draft Section 5.3.1.6 933 * When a peer sends a Adaptation Layer Indication parameter , SCTP 934 * delivers this notification to inform the application that of the 935 * peers requested adaptation layer. 936 */ 937 if (asoc->peer.adaptation_ind) { 938 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 939 if (!ev) 940 goto nomem; 941 942 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 943 SCTP_ULPEVENT(ev)); 944 } 945 946 return SCTP_DISPOSITION_CONSUME; 947 nomem: 948 return SCTP_DISPOSITION_NOMEM; 949 } 950 951 /* Generate and sendout a heartbeat packet. */ 952 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 953 const struct sctp_association *asoc, 954 const sctp_subtype_t type, 955 void *arg, 956 sctp_cmd_seq_t *commands) 957 { 958 struct sctp_transport *transport = (struct sctp_transport *) arg; 959 struct sctp_chunk *reply; 960 961 /* Send a heartbeat to our peer. */ 962 reply = sctp_make_heartbeat(asoc, transport); 963 if (!reply) 964 return SCTP_DISPOSITION_NOMEM; 965 966 /* Set rto_pending indicating that an RTT measurement 967 * is started with this heartbeat chunk. 968 */ 969 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 970 SCTP_TRANSPORT(transport)); 971 972 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 973 return SCTP_DISPOSITION_CONSUME; 974 } 975 976 /* Generate a HEARTBEAT packet on the given transport. */ 977 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 978 const struct sctp_endpoint *ep, 979 const struct sctp_association *asoc, 980 const sctp_subtype_t type, 981 void *arg, 982 sctp_cmd_seq_t *commands) 983 { 984 struct sctp_transport *transport = (struct sctp_transport *) arg; 985 986 if (asoc->overall_error_count >= asoc->max_retrans) { 987 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 988 SCTP_ERROR(ETIMEDOUT)); 989 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 990 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 991 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 992 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 993 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 994 return SCTP_DISPOSITION_DELETE_TCB; 995 } 996 997 /* Section 3.3.5. 998 * The Sender-specific Heartbeat Info field should normally include 999 * information about the sender's current time when this HEARTBEAT 1000 * chunk is sent and the destination transport address to which this 1001 * HEARTBEAT is sent (see Section 8.3). 1002 */ 1003 1004 if (transport->param_flags & SPP_HB_ENABLE) { 1005 if (SCTP_DISPOSITION_NOMEM == 1006 sctp_sf_heartbeat(ep, asoc, type, arg, 1007 commands)) 1008 return SCTP_DISPOSITION_NOMEM; 1009 1010 /* Set transport error counter and association error counter 1011 * when sending heartbeat. 1012 */ 1013 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1014 SCTP_TRANSPORT(transport)); 1015 } 1016 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1017 SCTP_TRANSPORT(transport)); 1018 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1019 SCTP_TRANSPORT(transport)); 1020 1021 return SCTP_DISPOSITION_CONSUME; 1022 } 1023 1024 /* resend asoc strreset_chunk. */ 1025 sctp_disposition_t sctp_sf_send_reconf(struct net *net, 1026 const struct sctp_endpoint *ep, 1027 const struct sctp_association *asoc, 1028 const sctp_subtype_t type, void *arg, 1029 sctp_cmd_seq_t *commands) 1030 { 1031 struct sctp_transport *transport = arg; 1032 1033 if (asoc->overall_error_count >= asoc->max_retrans) { 1034 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1035 SCTP_ERROR(ETIMEDOUT)); 1036 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1037 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1038 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1039 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1040 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1041 return SCTP_DISPOSITION_DELETE_TCB; 1042 } 1043 1044 sctp_chunk_hold(asoc->strreset_chunk); 1045 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1046 SCTP_CHUNK(asoc->strreset_chunk)); 1047 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1048 1049 return SCTP_DISPOSITION_CONSUME; 1050 } 1051 1052 /* 1053 * Process an heartbeat request. 1054 * 1055 * Section: 8.3 Path Heartbeat 1056 * The receiver of the HEARTBEAT should immediately respond with a 1057 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1058 * from the received HEARTBEAT chunk. 1059 * 1060 * Verification Tag: 8.5 Verification Tag [Normal verification] 1061 * When receiving an SCTP packet, the endpoint MUST ensure that the 1062 * value in the Verification Tag field of the received SCTP packet 1063 * matches its own Tag. If the received Verification Tag value does not 1064 * match the receiver's own tag value, the receiver shall silently 1065 * discard the packet and shall not process it any further except for 1066 * those cases listed in Section 8.5.1 below. 1067 * 1068 * Inputs 1069 * (endpoint, asoc, chunk) 1070 * 1071 * Outputs 1072 * (asoc, reply_msg, msg_up, timers, counters) 1073 * 1074 * The return value is the disposition of the chunk. 1075 */ 1076 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1077 const struct sctp_endpoint *ep, 1078 const struct sctp_association *asoc, 1079 const sctp_subtype_t type, 1080 void *arg, 1081 sctp_cmd_seq_t *commands) 1082 { 1083 sctp_paramhdr_t *param_hdr; 1084 struct sctp_chunk *chunk = arg; 1085 struct sctp_chunk *reply; 1086 size_t paylen = 0; 1087 1088 if (!sctp_vtag_verify(chunk, asoc)) 1089 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1090 1091 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1092 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1093 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1094 commands); 1095 1096 /* 8.3 The receiver of the HEARTBEAT should immediately 1097 * respond with a HEARTBEAT ACK that contains the Heartbeat 1098 * Information field copied from the received HEARTBEAT chunk. 1099 */ 1100 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1101 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr; 1102 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1103 1104 if (ntohs(param_hdr->length) > paylen) 1105 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1106 param_hdr, commands); 1107 1108 if (!pskb_pull(chunk->skb, paylen)) 1109 goto nomem; 1110 1111 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1112 if (!reply) 1113 goto nomem; 1114 1115 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1116 return SCTP_DISPOSITION_CONSUME; 1117 1118 nomem: 1119 return SCTP_DISPOSITION_NOMEM; 1120 } 1121 1122 /* 1123 * Process the returning HEARTBEAT ACK. 1124 * 1125 * Section: 8.3 Path Heartbeat 1126 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1127 * should clear the error counter of the destination transport 1128 * address to which the HEARTBEAT was sent, and mark the destination 1129 * transport address as active if it is not so marked. The endpoint may 1130 * optionally report to the upper layer when an inactive destination 1131 * address is marked as active due to the reception of the latest 1132 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1133 * clear the association overall error count as well (as defined 1134 * in section 8.1). 1135 * 1136 * The receiver of the HEARTBEAT ACK should also perform an RTT 1137 * measurement for that destination transport address using the time 1138 * value carried in the HEARTBEAT ACK chunk. 1139 * 1140 * Verification Tag: 8.5 Verification Tag [Normal verification] 1141 * 1142 * Inputs 1143 * (endpoint, asoc, chunk) 1144 * 1145 * Outputs 1146 * (asoc, reply_msg, msg_up, timers, counters) 1147 * 1148 * The return value is the disposition of the chunk. 1149 */ 1150 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1151 const struct sctp_endpoint *ep, 1152 const struct sctp_association *asoc, 1153 const sctp_subtype_t type, 1154 void *arg, 1155 sctp_cmd_seq_t *commands) 1156 { 1157 struct sctp_chunk *chunk = arg; 1158 union sctp_addr from_addr; 1159 struct sctp_transport *link; 1160 sctp_sender_hb_info_t *hbinfo; 1161 unsigned long max_interval; 1162 1163 if (!sctp_vtag_verify(chunk, asoc)) 1164 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1165 1166 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1167 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1168 sizeof(sctp_sender_hb_info_t))) 1169 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1170 commands); 1171 1172 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1173 /* Make sure that the length of the parameter is what we expect */ 1174 if (ntohs(hbinfo->param_hdr.length) != 1175 sizeof(sctp_sender_hb_info_t)) { 1176 return SCTP_DISPOSITION_DISCARD; 1177 } 1178 1179 from_addr = hbinfo->daddr; 1180 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1181 1182 /* This should never happen, but lets log it if so. */ 1183 if (unlikely(!link)) { 1184 if (from_addr.sa.sa_family == AF_INET6) { 1185 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1186 __func__, 1187 asoc, 1188 &from_addr.v6.sin6_addr); 1189 } else { 1190 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1191 __func__, 1192 asoc, 1193 &from_addr.v4.sin_addr.s_addr); 1194 } 1195 return SCTP_DISPOSITION_DISCARD; 1196 } 1197 1198 /* Validate the 64-bit random nonce. */ 1199 if (hbinfo->hb_nonce != link->hb_nonce) 1200 return SCTP_DISPOSITION_DISCARD; 1201 1202 max_interval = link->hbinterval + link->rto; 1203 1204 /* Check if the timestamp looks valid. */ 1205 if (time_after(hbinfo->sent_at, jiffies) || 1206 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1207 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1208 "for transport:%p\n", __func__, link); 1209 1210 return SCTP_DISPOSITION_DISCARD; 1211 } 1212 1213 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1214 * the HEARTBEAT should clear the error counter of the 1215 * destination transport address to which the HEARTBEAT was 1216 * sent and mark the destination transport address as active if 1217 * it is not so marked. 1218 */ 1219 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1220 1221 return SCTP_DISPOSITION_CONSUME; 1222 } 1223 1224 /* Helper function to send out an abort for the restart 1225 * condition. 1226 */ 1227 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1228 struct sctp_chunk *init, 1229 sctp_cmd_seq_t *commands) 1230 { 1231 int len; 1232 struct sctp_packet *pkt; 1233 union sctp_addr_param *addrparm; 1234 struct sctp_errhdr *errhdr; 1235 struct sctp_endpoint *ep; 1236 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1237 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1238 1239 /* Build the error on the stack. We are way to malloc crazy 1240 * throughout the code today. 1241 */ 1242 errhdr = (struct sctp_errhdr *)buffer; 1243 addrparm = (union sctp_addr_param *)errhdr->variable; 1244 1245 /* Copy into a parm format. */ 1246 len = af->to_addr_param(ssa, addrparm); 1247 len += sizeof(sctp_errhdr_t); 1248 1249 errhdr->cause = SCTP_ERROR_RESTART; 1250 errhdr->length = htons(len); 1251 1252 /* Assign to the control socket. */ 1253 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1254 1255 /* Association is NULL since this may be a restart attack and we 1256 * want to send back the attacker's vtag. 1257 */ 1258 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1259 1260 if (!pkt) 1261 goto out; 1262 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1263 1264 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1265 1266 /* Discard the rest of the inbound packet. */ 1267 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1268 1269 out: 1270 /* Even if there is no memory, treat as a failure so 1271 * the packet will get dropped. 1272 */ 1273 return 0; 1274 } 1275 1276 static bool list_has_sctp_addr(const struct list_head *list, 1277 union sctp_addr *ipaddr) 1278 { 1279 struct sctp_transport *addr; 1280 1281 list_for_each_entry(addr, list, transports) { 1282 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1283 return true; 1284 } 1285 1286 return false; 1287 } 1288 /* A restart is occurring, check to make sure no new addresses 1289 * are being added as we may be under a takeover attack. 1290 */ 1291 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1292 const struct sctp_association *asoc, 1293 struct sctp_chunk *init, 1294 sctp_cmd_seq_t *commands) 1295 { 1296 struct net *net = sock_net(new_asoc->base.sk); 1297 struct sctp_transport *new_addr; 1298 int ret = 1; 1299 1300 /* Implementor's Guide - Section 5.2.2 1301 * ... 1302 * Before responding the endpoint MUST check to see if the 1303 * unexpected INIT adds new addresses to the association. If new 1304 * addresses are added to the association, the endpoint MUST respond 1305 * with an ABORT.. 1306 */ 1307 1308 /* Search through all current addresses and make sure 1309 * we aren't adding any new ones. 1310 */ 1311 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1312 transports) { 1313 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1314 &new_addr->ipaddr)) { 1315 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1316 commands); 1317 ret = 0; 1318 break; 1319 } 1320 } 1321 1322 /* Return success if all addresses were found. */ 1323 return ret; 1324 } 1325 1326 /* Populate the verification/tie tags based on overlapping INIT 1327 * scenario. 1328 * 1329 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1330 */ 1331 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1332 const struct sctp_association *asoc) 1333 { 1334 switch (asoc->state) { 1335 1336 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1337 1338 case SCTP_STATE_COOKIE_WAIT: 1339 new_asoc->c.my_vtag = asoc->c.my_vtag; 1340 new_asoc->c.my_ttag = asoc->c.my_vtag; 1341 new_asoc->c.peer_ttag = 0; 1342 break; 1343 1344 case SCTP_STATE_COOKIE_ECHOED: 1345 new_asoc->c.my_vtag = asoc->c.my_vtag; 1346 new_asoc->c.my_ttag = asoc->c.my_vtag; 1347 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1348 break; 1349 1350 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1351 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1352 */ 1353 default: 1354 new_asoc->c.my_ttag = asoc->c.my_vtag; 1355 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1356 break; 1357 } 1358 1359 /* Other parameters for the endpoint SHOULD be copied from the 1360 * existing parameters of the association (e.g. number of 1361 * outbound streams) into the INIT ACK and cookie. 1362 */ 1363 new_asoc->rwnd = asoc->rwnd; 1364 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1365 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1366 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1367 } 1368 1369 /* 1370 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1371 * handling action. 1372 * 1373 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1374 * 1375 * Returns value representing action to be taken. These action values 1376 * correspond to Action/Description values in RFC 2960, Table 2. 1377 */ 1378 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1379 const struct sctp_association *asoc) 1380 { 1381 /* In this case, the peer may have restarted. */ 1382 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1383 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1384 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1385 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1386 return 'A'; 1387 1388 /* Collision case B. */ 1389 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1390 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1391 (0 == asoc->c.peer_vtag))) { 1392 return 'B'; 1393 } 1394 1395 /* Collision case D. */ 1396 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1397 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1398 return 'D'; 1399 1400 /* Collision case C. */ 1401 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1402 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1403 (0 == new_asoc->c.my_ttag) && 1404 (0 == new_asoc->c.peer_ttag)) 1405 return 'C'; 1406 1407 /* No match to any of the special cases; discard this packet. */ 1408 return 'E'; 1409 } 1410 1411 /* Common helper routine for both duplicate and simulataneous INIT 1412 * chunk handling. 1413 */ 1414 static sctp_disposition_t sctp_sf_do_unexpected_init( 1415 struct net *net, 1416 const struct sctp_endpoint *ep, 1417 const struct sctp_association *asoc, 1418 const sctp_subtype_t type, 1419 void *arg, sctp_cmd_seq_t *commands) 1420 { 1421 sctp_disposition_t retval; 1422 struct sctp_chunk *chunk = arg; 1423 struct sctp_chunk *repl; 1424 struct sctp_association *new_asoc; 1425 struct sctp_chunk *err_chunk; 1426 struct sctp_packet *packet; 1427 sctp_unrecognized_param_t *unk_param; 1428 int len; 1429 1430 /* 6.10 Bundling 1431 * An endpoint MUST NOT bundle INIT, INIT ACK or 1432 * SHUTDOWN COMPLETE with any other chunks. 1433 * 1434 * IG Section 2.11.2 1435 * Furthermore, we require that the receiver of an INIT chunk MUST 1436 * enforce these rules by silently discarding an arriving packet 1437 * with an INIT chunk that is bundled with other chunks. 1438 */ 1439 if (!chunk->singleton) 1440 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1441 1442 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1443 * Tag. 1444 */ 1445 if (chunk->sctp_hdr->vtag != 0) 1446 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1447 1448 /* Make sure that the INIT chunk has a valid length. 1449 * In this case, we generate a protocol violation since we have 1450 * an association established. 1451 */ 1452 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1453 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1454 commands); 1455 /* Grab the INIT header. */ 1456 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1457 1458 /* Tag the variable length parameters. */ 1459 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1460 1461 /* Verify the INIT chunk before processing it. */ 1462 err_chunk = NULL; 1463 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1464 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1465 &err_chunk)) { 1466 /* This chunk contains fatal error. It is to be discarded. 1467 * Send an ABORT, with causes if there is any. 1468 */ 1469 if (err_chunk) { 1470 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1471 (__u8 *)(err_chunk->chunk_hdr) + 1472 sizeof(sctp_chunkhdr_t), 1473 ntohs(err_chunk->chunk_hdr->length) - 1474 sizeof(sctp_chunkhdr_t)); 1475 1476 if (packet) { 1477 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1478 SCTP_PACKET(packet)); 1479 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1480 retval = SCTP_DISPOSITION_CONSUME; 1481 } else { 1482 retval = SCTP_DISPOSITION_NOMEM; 1483 } 1484 goto cleanup; 1485 } else { 1486 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1487 commands); 1488 } 1489 } 1490 1491 /* 1492 * Other parameters for the endpoint SHOULD be copied from the 1493 * existing parameters of the association (e.g. number of 1494 * outbound streams) into the INIT ACK and cookie. 1495 * FIXME: We are copying parameters from the endpoint not the 1496 * association. 1497 */ 1498 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1499 if (!new_asoc) 1500 goto nomem; 1501 1502 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1503 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1504 goto nomem; 1505 1506 /* In the outbound INIT ACK the endpoint MUST copy its current 1507 * Verification Tag and Peers Verification tag into a reserved 1508 * place (local tie-tag and per tie-tag) within the state cookie. 1509 */ 1510 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1511 (sctp_init_chunk_t *)chunk->chunk_hdr, 1512 GFP_ATOMIC)) 1513 goto nomem; 1514 1515 /* Make sure no new addresses are being added during the 1516 * restart. Do not do this check for COOKIE-WAIT state, 1517 * since there are no peer addresses to check against. 1518 * Upon return an ABORT will have been sent if needed. 1519 */ 1520 if (!sctp_state(asoc, COOKIE_WAIT)) { 1521 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1522 commands)) { 1523 retval = SCTP_DISPOSITION_CONSUME; 1524 goto nomem_retval; 1525 } 1526 } 1527 1528 sctp_tietags_populate(new_asoc, asoc); 1529 1530 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1531 1532 /* If there are errors need to be reported for unknown parameters, 1533 * make sure to reserve enough room in the INIT ACK for them. 1534 */ 1535 len = 0; 1536 if (err_chunk) { 1537 len = ntohs(err_chunk->chunk_hdr->length) - 1538 sizeof(sctp_chunkhdr_t); 1539 } 1540 1541 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1542 if (!repl) 1543 goto nomem; 1544 1545 /* If there are errors need to be reported for unknown parameters, 1546 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1547 * parameter. 1548 */ 1549 if (err_chunk) { 1550 /* Get the "Unrecognized parameter" parameter(s) out of the 1551 * ERROR chunk generated by sctp_verify_init(). Since the 1552 * error cause code for "unknown parameter" and the 1553 * "Unrecognized parameter" type is the same, we can 1554 * construct the parameters in INIT ACK by copying the 1555 * ERROR causes over. 1556 */ 1557 unk_param = (sctp_unrecognized_param_t *) 1558 ((__u8 *)(err_chunk->chunk_hdr) + 1559 sizeof(sctp_chunkhdr_t)); 1560 /* Replace the cause code with the "Unrecognized parameter" 1561 * parameter type. 1562 */ 1563 sctp_addto_chunk(repl, len, unk_param); 1564 } 1565 1566 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1567 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1568 1569 /* 1570 * Note: After sending out INIT ACK with the State Cookie parameter, 1571 * "Z" MUST NOT allocate any resources for this new association. 1572 * Otherwise, "Z" will be vulnerable to resource attacks. 1573 */ 1574 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1575 retval = SCTP_DISPOSITION_CONSUME; 1576 1577 return retval; 1578 1579 nomem: 1580 retval = SCTP_DISPOSITION_NOMEM; 1581 nomem_retval: 1582 if (new_asoc) 1583 sctp_association_free(new_asoc); 1584 cleanup: 1585 if (err_chunk) 1586 sctp_chunk_free(err_chunk); 1587 return retval; 1588 } 1589 1590 /* 1591 * Handle simultaneous INIT. 1592 * This means we started an INIT and then we got an INIT request from 1593 * our peer. 1594 * 1595 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1596 * This usually indicates an initialization collision, i.e., each 1597 * endpoint is attempting, at about the same time, to establish an 1598 * association with the other endpoint. 1599 * 1600 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1601 * endpoint MUST respond with an INIT ACK using the same parameters it 1602 * sent in its original INIT chunk (including its Verification Tag, 1603 * unchanged). These original parameters are combined with those from the 1604 * newly received INIT chunk. The endpoint shall also generate a State 1605 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1606 * INIT to calculate the State Cookie. 1607 * 1608 * After that, the endpoint MUST NOT change its state, the T1-init 1609 * timer shall be left running and the corresponding TCB MUST NOT be 1610 * destroyed. The normal procedures for handling State Cookies when 1611 * a TCB exists will resolve the duplicate INITs to a single association. 1612 * 1613 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1614 * its Tie-Tags with the Tag information of itself and its peer (see 1615 * section 5.2.2 for a description of the Tie-Tags). 1616 * 1617 * Verification Tag: Not explicit, but an INIT can not have a valid 1618 * verification tag, so we skip the check. 1619 * 1620 * Inputs 1621 * (endpoint, asoc, chunk) 1622 * 1623 * Outputs 1624 * (asoc, reply_msg, msg_up, timers, counters) 1625 * 1626 * The return value is the disposition of the chunk. 1627 */ 1628 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1629 const struct sctp_endpoint *ep, 1630 const struct sctp_association *asoc, 1631 const sctp_subtype_t type, 1632 void *arg, 1633 sctp_cmd_seq_t *commands) 1634 { 1635 /* Call helper to do the real work for both simulataneous and 1636 * duplicate INIT chunk handling. 1637 */ 1638 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1639 } 1640 1641 /* 1642 * Handle duplicated INIT messages. These are usually delayed 1643 * restransmissions. 1644 * 1645 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1646 * COOKIE-ECHOED and COOKIE-WAIT 1647 * 1648 * Unless otherwise stated, upon reception of an unexpected INIT for 1649 * this association, the endpoint shall generate an INIT ACK with a 1650 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1651 * current Verification Tag and peer's Verification Tag into a reserved 1652 * place within the state cookie. We shall refer to these locations as 1653 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1654 * containing this INIT ACK MUST carry a Verification Tag value equal to 1655 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1656 * MUST contain a new Initiation Tag (randomly generated see Section 1657 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1658 * existing parameters of the association (e.g. number of outbound 1659 * streams) into the INIT ACK and cookie. 1660 * 1661 * After sending out the INIT ACK, the endpoint shall take no further 1662 * actions, i.e., the existing association, including its current state, 1663 * and the corresponding TCB MUST NOT be changed. 1664 * 1665 * Note: Only when a TCB exists and the association is not in a COOKIE- 1666 * WAIT state are the Tie-Tags populated. For a normal association INIT 1667 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1668 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1669 * State Cookie are populated as specified in section 5.2.1. 1670 * 1671 * Verification Tag: Not specified, but an INIT has no way of knowing 1672 * what the verification tag could be, so we ignore it. 1673 * 1674 * Inputs 1675 * (endpoint, asoc, chunk) 1676 * 1677 * Outputs 1678 * (asoc, reply_msg, msg_up, timers, counters) 1679 * 1680 * The return value is the disposition of the chunk. 1681 */ 1682 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1683 const struct sctp_endpoint *ep, 1684 const struct sctp_association *asoc, 1685 const sctp_subtype_t type, 1686 void *arg, 1687 sctp_cmd_seq_t *commands) 1688 { 1689 /* Call helper to do the real work for both simulataneous and 1690 * duplicate INIT chunk handling. 1691 */ 1692 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1693 } 1694 1695 1696 /* 1697 * Unexpected INIT-ACK handler. 1698 * 1699 * Section 5.2.3 1700 * If an INIT ACK received by an endpoint in any state other than the 1701 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1702 * An unexpected INIT ACK usually indicates the processing of an old or 1703 * duplicated INIT chunk. 1704 */ 1705 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1706 const struct sctp_endpoint *ep, 1707 const struct sctp_association *asoc, 1708 const sctp_subtype_t type, 1709 void *arg, sctp_cmd_seq_t *commands) 1710 { 1711 /* Per the above section, we'll discard the chunk if we have an 1712 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1713 */ 1714 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1715 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1716 else 1717 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1718 } 1719 1720 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1721 * 1722 * Section 5.2.4 1723 * A) In this case, the peer may have restarted. 1724 */ 1725 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1726 const struct sctp_endpoint *ep, 1727 const struct sctp_association *asoc, 1728 struct sctp_chunk *chunk, 1729 sctp_cmd_seq_t *commands, 1730 struct sctp_association *new_asoc) 1731 { 1732 sctp_init_chunk_t *peer_init; 1733 struct sctp_ulpevent *ev; 1734 struct sctp_chunk *repl; 1735 struct sctp_chunk *err; 1736 sctp_disposition_t disposition; 1737 1738 /* new_asoc is a brand-new association, so these are not yet 1739 * side effects--it is safe to run them here. 1740 */ 1741 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1742 1743 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1744 GFP_ATOMIC)) 1745 goto nomem; 1746 1747 /* Make sure no new addresses are being added during the 1748 * restart. Though this is a pretty complicated attack 1749 * since you'd have to get inside the cookie. 1750 */ 1751 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1752 return SCTP_DISPOSITION_CONSUME; 1753 } 1754 1755 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1756 * the peer has restarted (Action A), it MUST NOT setup a new 1757 * association but instead resend the SHUTDOWN ACK and send an ERROR 1758 * chunk with a "Cookie Received while Shutting Down" error cause to 1759 * its peer. 1760 */ 1761 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1762 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1763 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1764 chunk, commands); 1765 if (SCTP_DISPOSITION_NOMEM == disposition) 1766 goto nomem; 1767 1768 err = sctp_make_op_error(asoc, chunk, 1769 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1770 NULL, 0, 0); 1771 if (err) 1772 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1773 SCTP_CHUNK(err)); 1774 1775 return SCTP_DISPOSITION_CONSUME; 1776 } 1777 1778 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1779 * data. Consider the optional choice of resending of this data. 1780 */ 1781 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1782 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1783 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1784 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1785 1786 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1787 * and ASCONF-ACK cache. 1788 */ 1789 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1790 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1791 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1792 1793 repl = sctp_make_cookie_ack(new_asoc, chunk); 1794 if (!repl) 1795 goto nomem; 1796 1797 /* Report association restart to upper layer. */ 1798 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1799 new_asoc->c.sinit_num_ostreams, 1800 new_asoc->c.sinit_max_instreams, 1801 NULL, GFP_ATOMIC); 1802 if (!ev) 1803 goto nomem_ev; 1804 1805 /* Update the content of current association. */ 1806 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1807 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1808 if (sctp_state(asoc, SHUTDOWN_PENDING) && 1809 (sctp_sstate(asoc->base.sk, CLOSING) || 1810 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1811 /* if were currently in SHUTDOWN_PENDING, but the socket 1812 * has been closed by user, don't transition to ESTABLISHED. 1813 * Instead trigger SHUTDOWN bundled with COOKIE_ACK. 1814 */ 1815 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1816 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1817 SCTP_ST_CHUNK(0), NULL, 1818 commands); 1819 } else { 1820 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1821 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1822 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1823 } 1824 return SCTP_DISPOSITION_CONSUME; 1825 1826 nomem_ev: 1827 sctp_chunk_free(repl); 1828 nomem: 1829 return SCTP_DISPOSITION_NOMEM; 1830 } 1831 1832 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1833 * 1834 * Section 5.2.4 1835 * B) In this case, both sides may be attempting to start an association 1836 * at about the same time but the peer endpoint started its INIT 1837 * after responding to the local endpoint's INIT 1838 */ 1839 /* This case represents an initialization collision. */ 1840 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1841 const struct sctp_endpoint *ep, 1842 const struct sctp_association *asoc, 1843 struct sctp_chunk *chunk, 1844 sctp_cmd_seq_t *commands, 1845 struct sctp_association *new_asoc) 1846 { 1847 sctp_init_chunk_t *peer_init; 1848 struct sctp_chunk *repl; 1849 1850 /* new_asoc is a brand-new association, so these are not yet 1851 * side effects--it is safe to run them here. 1852 */ 1853 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1854 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1855 GFP_ATOMIC)) 1856 goto nomem; 1857 1858 /* Update the content of current association. */ 1859 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1860 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1861 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1862 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1863 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1864 1865 repl = sctp_make_cookie_ack(new_asoc, chunk); 1866 if (!repl) 1867 goto nomem; 1868 1869 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1870 1871 /* RFC 2960 5.1 Normal Establishment of an Association 1872 * 1873 * D) IMPLEMENTATION NOTE: An implementation may choose to 1874 * send the Communication Up notification to the SCTP user 1875 * upon reception of a valid COOKIE ECHO chunk. 1876 * 1877 * Sadly, this needs to be implemented as a side-effect, because 1878 * we are not guaranteed to have set the association id of the real 1879 * association and so these notifications need to be delayed until 1880 * the association id is allocated. 1881 */ 1882 1883 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1884 1885 /* Sockets API Draft Section 5.3.1.6 1886 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1887 * delivers this notification to inform the application that of the 1888 * peers requested adaptation layer. 1889 * 1890 * This also needs to be done as a side effect for the same reason as 1891 * above. 1892 */ 1893 if (asoc->peer.adaptation_ind) 1894 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1895 1896 return SCTP_DISPOSITION_CONSUME; 1897 1898 nomem: 1899 return SCTP_DISPOSITION_NOMEM; 1900 } 1901 1902 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1903 * 1904 * Section 5.2.4 1905 * C) In this case, the local endpoint's cookie has arrived late. 1906 * Before it arrived, the local endpoint sent an INIT and received an 1907 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1908 * but a new tag of its own. 1909 */ 1910 /* This case represents an initialization collision. */ 1911 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1912 const struct sctp_endpoint *ep, 1913 const struct sctp_association *asoc, 1914 struct sctp_chunk *chunk, 1915 sctp_cmd_seq_t *commands, 1916 struct sctp_association *new_asoc) 1917 { 1918 /* The cookie should be silently discarded. 1919 * The endpoint SHOULD NOT change states and should leave 1920 * any timers running. 1921 */ 1922 return SCTP_DISPOSITION_DISCARD; 1923 } 1924 1925 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1926 * 1927 * Section 5.2.4 1928 * 1929 * D) When both local and remote tags match the endpoint should always 1930 * enter the ESTABLISHED state, if it has not already done so. 1931 */ 1932 /* This case represents an initialization collision. */ 1933 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1934 const struct sctp_endpoint *ep, 1935 const struct sctp_association *asoc, 1936 struct sctp_chunk *chunk, 1937 sctp_cmd_seq_t *commands, 1938 struct sctp_association *new_asoc) 1939 { 1940 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1941 struct sctp_chunk *repl; 1942 1943 /* Clarification from Implementor's Guide: 1944 * D) When both local and remote tags match the endpoint should 1945 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1946 * It should stop any cookie timer that may be running and send 1947 * a COOKIE ACK. 1948 */ 1949 1950 /* Don't accidentally move back into established state. */ 1951 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1952 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1953 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1954 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1955 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1956 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1957 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1958 SCTP_NULL()); 1959 1960 /* RFC 2960 5.1 Normal Establishment of an Association 1961 * 1962 * D) IMPLEMENTATION NOTE: An implementation may choose 1963 * to send the Communication Up notification to the 1964 * SCTP user upon reception of a valid COOKIE 1965 * ECHO chunk. 1966 */ 1967 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1968 SCTP_COMM_UP, 0, 1969 asoc->c.sinit_num_ostreams, 1970 asoc->c.sinit_max_instreams, 1971 NULL, GFP_ATOMIC); 1972 if (!ev) 1973 goto nomem; 1974 1975 /* Sockets API Draft Section 5.3.1.6 1976 * When a peer sends a Adaptation Layer Indication parameter, 1977 * SCTP delivers this notification to inform the application 1978 * that of the peers requested adaptation layer. 1979 */ 1980 if (asoc->peer.adaptation_ind) { 1981 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1982 GFP_ATOMIC); 1983 if (!ai_ev) 1984 goto nomem; 1985 1986 } 1987 } 1988 1989 repl = sctp_make_cookie_ack(new_asoc, chunk); 1990 if (!repl) 1991 goto nomem; 1992 1993 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1994 1995 if (ev) 1996 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1997 SCTP_ULPEVENT(ev)); 1998 if (ai_ev) 1999 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2000 SCTP_ULPEVENT(ai_ev)); 2001 2002 return SCTP_DISPOSITION_CONSUME; 2003 2004 nomem: 2005 if (ai_ev) 2006 sctp_ulpevent_free(ai_ev); 2007 if (ev) 2008 sctp_ulpevent_free(ev); 2009 return SCTP_DISPOSITION_NOMEM; 2010 } 2011 2012 /* 2013 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2014 * chunk was retransmitted and then delayed in the network. 2015 * 2016 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2017 * 2018 * Verification Tag: None. Do cookie validation. 2019 * 2020 * Inputs 2021 * (endpoint, asoc, chunk) 2022 * 2023 * Outputs 2024 * (asoc, reply_msg, msg_up, timers, counters) 2025 * 2026 * The return value is the disposition of the chunk. 2027 */ 2028 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 2029 const struct sctp_endpoint *ep, 2030 const struct sctp_association *asoc, 2031 const sctp_subtype_t type, 2032 void *arg, 2033 sctp_cmd_seq_t *commands) 2034 { 2035 sctp_disposition_t retval; 2036 struct sctp_chunk *chunk = arg; 2037 struct sctp_association *new_asoc; 2038 int error = 0; 2039 char action; 2040 struct sctp_chunk *err_chk_p; 2041 2042 /* Make sure that the chunk has a valid length from the protocol 2043 * perspective. In this case check to make sure we have at least 2044 * enough for the chunk header. Cookie length verification is 2045 * done later. 2046 */ 2047 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2048 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2049 commands); 2050 2051 /* "Decode" the chunk. We have no optional parameters so we 2052 * are in good shape. 2053 */ 2054 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2055 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2056 sizeof(sctp_chunkhdr_t))) 2057 goto nomem; 2058 2059 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2060 * of a duplicate COOKIE ECHO match the Verification Tags of the 2061 * current association, consider the State Cookie valid even if 2062 * the lifespan is exceeded. 2063 */ 2064 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2065 &err_chk_p); 2066 2067 /* FIXME: 2068 * If the re-build failed, what is the proper error path 2069 * from here? 2070 * 2071 * [We should abort the association. --piggy] 2072 */ 2073 if (!new_asoc) { 2074 /* FIXME: Several errors are possible. A bad cookie should 2075 * be silently discarded, but think about logging it too. 2076 */ 2077 switch (error) { 2078 case -SCTP_IERROR_NOMEM: 2079 goto nomem; 2080 2081 case -SCTP_IERROR_STALE_COOKIE: 2082 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2083 err_chk_p); 2084 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2085 case -SCTP_IERROR_BAD_SIG: 2086 default: 2087 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2088 } 2089 } 2090 2091 /* Compare the tie_tag in cookie with the verification tag of 2092 * current association. 2093 */ 2094 action = sctp_tietags_compare(new_asoc, asoc); 2095 2096 switch (action) { 2097 case 'A': /* Association restart. */ 2098 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2099 new_asoc); 2100 break; 2101 2102 case 'B': /* Collision case B. */ 2103 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2104 new_asoc); 2105 break; 2106 2107 case 'C': /* Collision case C. */ 2108 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2109 new_asoc); 2110 break; 2111 2112 case 'D': /* Collision case D. */ 2113 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2114 new_asoc); 2115 break; 2116 2117 default: /* Discard packet for all others. */ 2118 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2119 break; 2120 } 2121 2122 /* Delete the tempory new association. */ 2123 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2124 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2125 2126 /* Restore association pointer to provide SCTP command interpeter 2127 * with a valid context in case it needs to manipulate 2128 * the queues */ 2129 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2130 SCTP_ASOC((struct sctp_association *)asoc)); 2131 2132 return retval; 2133 2134 nomem: 2135 return SCTP_DISPOSITION_NOMEM; 2136 } 2137 2138 /* 2139 * Process an ABORT. (SHUTDOWN-PENDING state) 2140 * 2141 * See sctp_sf_do_9_1_abort(). 2142 */ 2143 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2144 struct net *net, 2145 const struct sctp_endpoint *ep, 2146 const struct sctp_association *asoc, 2147 const sctp_subtype_t type, 2148 void *arg, 2149 sctp_cmd_seq_t *commands) 2150 { 2151 struct sctp_chunk *chunk = arg; 2152 2153 if (!sctp_vtag_verify_either(chunk, asoc)) 2154 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2155 2156 /* Make sure that the ABORT chunk has a valid length. 2157 * Since this is an ABORT chunk, we have to discard it 2158 * because of the following text: 2159 * RFC 2960, Section 3.3.7 2160 * If an endpoint receives an ABORT with a format error or for an 2161 * association that doesn't exist, it MUST silently discard it. 2162 * Because the length is "invalid", we can't really discard just 2163 * as we do not know its true length. So, to be safe, discard the 2164 * packet. 2165 */ 2166 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2167 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2168 2169 /* ADD-IP: Special case for ABORT chunks 2170 * F4) One special consideration is that ABORT Chunks arriving 2171 * destined to the IP address being deleted MUST be 2172 * ignored (see Section 5.3.1 for further details). 2173 */ 2174 if (SCTP_ADDR_DEL == 2175 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2176 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2177 2178 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2179 } 2180 2181 /* 2182 * Process an ABORT. (SHUTDOWN-SENT state) 2183 * 2184 * See sctp_sf_do_9_1_abort(). 2185 */ 2186 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2187 const struct sctp_endpoint *ep, 2188 const struct sctp_association *asoc, 2189 const sctp_subtype_t type, 2190 void *arg, 2191 sctp_cmd_seq_t *commands) 2192 { 2193 struct sctp_chunk *chunk = arg; 2194 2195 if (!sctp_vtag_verify_either(chunk, asoc)) 2196 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2197 2198 /* Make sure that the ABORT chunk has a valid length. 2199 * Since this is an ABORT chunk, we have to discard it 2200 * because of the following text: 2201 * RFC 2960, Section 3.3.7 2202 * If an endpoint receives an ABORT with a format error or for an 2203 * association that doesn't exist, it MUST silently discard it. 2204 * Because the length is "invalid", we can't really discard just 2205 * as we do not know its true length. So, to be safe, discard the 2206 * packet. 2207 */ 2208 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2209 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2210 2211 /* ADD-IP: Special case for ABORT chunks 2212 * F4) One special consideration is that ABORT Chunks arriving 2213 * destined to the IP address being deleted MUST be 2214 * ignored (see Section 5.3.1 for further details). 2215 */ 2216 if (SCTP_ADDR_DEL == 2217 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2218 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2219 2220 /* Stop the T2-shutdown timer. */ 2221 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2222 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2223 2224 /* Stop the T5-shutdown guard timer. */ 2225 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2226 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2227 2228 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2229 } 2230 2231 /* 2232 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2233 * 2234 * See sctp_sf_do_9_1_abort(). 2235 */ 2236 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2237 struct net *net, 2238 const struct sctp_endpoint *ep, 2239 const struct sctp_association *asoc, 2240 const sctp_subtype_t type, 2241 void *arg, 2242 sctp_cmd_seq_t *commands) 2243 { 2244 /* The same T2 timer, so we should be able to use 2245 * common function with the SHUTDOWN-SENT state. 2246 */ 2247 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2248 } 2249 2250 /* 2251 * Handle an Error received in COOKIE_ECHOED state. 2252 * 2253 * Only handle the error type of stale COOKIE Error, the other errors will 2254 * be ignored. 2255 * 2256 * Inputs 2257 * (endpoint, asoc, chunk) 2258 * 2259 * Outputs 2260 * (asoc, reply_msg, msg_up, timers, counters) 2261 * 2262 * The return value is the disposition of the chunk. 2263 */ 2264 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2265 const struct sctp_endpoint *ep, 2266 const struct sctp_association *asoc, 2267 const sctp_subtype_t type, 2268 void *arg, 2269 sctp_cmd_seq_t *commands) 2270 { 2271 struct sctp_chunk *chunk = arg; 2272 sctp_errhdr_t *err; 2273 2274 if (!sctp_vtag_verify(chunk, asoc)) 2275 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2276 2277 /* Make sure that the ERROR chunk has a valid length. 2278 * The parameter walking depends on this as well. 2279 */ 2280 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2281 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2282 commands); 2283 2284 /* Process the error here */ 2285 /* FUTURE FIXME: When PR-SCTP related and other optional 2286 * parms are emitted, this will have to change to handle multiple 2287 * errors. 2288 */ 2289 sctp_walk_errors(err, chunk->chunk_hdr) { 2290 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2291 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2292 arg, commands); 2293 } 2294 2295 /* It is possible to have malformed error causes, and that 2296 * will cause us to end the walk early. However, since 2297 * we are discarding the packet, there should be no adverse 2298 * affects. 2299 */ 2300 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2301 } 2302 2303 /* 2304 * Handle a Stale COOKIE Error 2305 * 2306 * Section: 5.2.6 Handle Stale COOKIE Error 2307 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2308 * one of the following three alternatives. 2309 * ... 2310 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2311 * Preservative parameter requesting an extension to the lifetime of 2312 * the State Cookie. When calculating the time extension, an 2313 * implementation SHOULD use the RTT information measured based on the 2314 * previous COOKIE ECHO / ERROR exchange, and should add no more 2315 * than 1 second beyond the measured RTT, due to long State Cookie 2316 * lifetimes making the endpoint more subject to a replay attack. 2317 * 2318 * Verification Tag: Not explicit, but safe to ignore. 2319 * 2320 * Inputs 2321 * (endpoint, asoc, chunk) 2322 * 2323 * Outputs 2324 * (asoc, reply_msg, msg_up, timers, counters) 2325 * 2326 * The return value is the disposition of the chunk. 2327 */ 2328 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2329 const struct sctp_endpoint *ep, 2330 const struct sctp_association *asoc, 2331 const sctp_subtype_t type, 2332 void *arg, 2333 sctp_cmd_seq_t *commands) 2334 { 2335 struct sctp_chunk *chunk = arg; 2336 u32 stale; 2337 sctp_cookie_preserve_param_t bht; 2338 sctp_errhdr_t *err; 2339 struct sctp_chunk *reply; 2340 struct sctp_bind_addr *bp; 2341 int attempts = asoc->init_err_counter + 1; 2342 2343 if (attempts > asoc->max_init_attempts) { 2344 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2345 SCTP_ERROR(ETIMEDOUT)); 2346 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2347 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2348 return SCTP_DISPOSITION_DELETE_TCB; 2349 } 2350 2351 err = (sctp_errhdr_t *)(chunk->skb->data); 2352 2353 /* When calculating the time extension, an implementation 2354 * SHOULD use the RTT information measured based on the 2355 * previous COOKIE ECHO / ERROR exchange, and should add no 2356 * more than 1 second beyond the measured RTT, due to long 2357 * State Cookie lifetimes making the endpoint more subject to 2358 * a replay attack. 2359 * Measure of Staleness's unit is usec. (1/1000000 sec) 2360 * Suggested Cookie Life-span Increment's unit is msec. 2361 * (1/1000 sec) 2362 * In general, if you use the suggested cookie life, the value 2363 * found in the field of measure of staleness should be doubled 2364 * to give ample time to retransmit the new cookie and thus 2365 * yield a higher probability of success on the reattempt. 2366 */ 2367 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2368 stale = (stale * 2) / 1000; 2369 2370 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2371 bht.param_hdr.length = htons(sizeof(bht)); 2372 bht.lifespan_increment = htonl(stale); 2373 2374 /* Build that new INIT chunk. */ 2375 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2376 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2377 if (!reply) 2378 goto nomem; 2379 2380 sctp_addto_chunk(reply, sizeof(bht), &bht); 2381 2382 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2383 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2384 2385 /* Stop pending T3-rtx and heartbeat timers */ 2386 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2387 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2388 2389 /* Delete non-primary peer ip addresses since we are transitioning 2390 * back to the COOKIE-WAIT state 2391 */ 2392 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2393 2394 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2395 * resend 2396 */ 2397 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2398 SCTP_TRANSPORT(asoc->peer.primary_path)); 2399 2400 /* Cast away the const modifier, as we want to just 2401 * rerun it through as a sideffect. 2402 */ 2403 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2404 2405 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2406 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2407 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2408 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2409 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2410 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2411 2412 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2413 2414 return SCTP_DISPOSITION_CONSUME; 2415 2416 nomem: 2417 return SCTP_DISPOSITION_NOMEM; 2418 } 2419 2420 /* 2421 * Process an ABORT. 2422 * 2423 * Section: 9.1 2424 * After checking the Verification Tag, the receiving endpoint shall 2425 * remove the association from its record, and shall report the 2426 * termination to its upper layer. 2427 * 2428 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2429 * B) Rules for packet carrying ABORT: 2430 * 2431 * - The endpoint shall always fill in the Verification Tag field of the 2432 * outbound packet with the destination endpoint's tag value if it 2433 * is known. 2434 * 2435 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2436 * MUST follow the procedure described in Section 8.4. 2437 * 2438 * - The receiver MUST accept the packet if the Verification Tag 2439 * matches either its own tag, OR the tag of its peer. Otherwise, the 2440 * receiver MUST silently discard the packet and take no further 2441 * action. 2442 * 2443 * Inputs 2444 * (endpoint, asoc, chunk) 2445 * 2446 * Outputs 2447 * (asoc, reply_msg, msg_up, timers, counters) 2448 * 2449 * The return value is the disposition of the chunk. 2450 */ 2451 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2452 const struct sctp_endpoint *ep, 2453 const struct sctp_association *asoc, 2454 const sctp_subtype_t type, 2455 void *arg, 2456 sctp_cmd_seq_t *commands) 2457 { 2458 struct sctp_chunk *chunk = arg; 2459 2460 if (!sctp_vtag_verify_either(chunk, asoc)) 2461 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2462 2463 /* Make sure that the ABORT chunk has a valid length. 2464 * Since this is an ABORT chunk, we have to discard it 2465 * because of the following text: 2466 * RFC 2960, Section 3.3.7 2467 * If an endpoint receives an ABORT with a format error or for an 2468 * association that doesn't exist, it MUST silently discard it. 2469 * Because the length is "invalid", we can't really discard just 2470 * as we do not know its true length. So, to be safe, discard the 2471 * packet. 2472 */ 2473 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2474 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2475 2476 /* ADD-IP: Special case for ABORT chunks 2477 * F4) One special consideration is that ABORT Chunks arriving 2478 * destined to the IP address being deleted MUST be 2479 * ignored (see Section 5.3.1 for further details). 2480 */ 2481 if (SCTP_ADDR_DEL == 2482 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2483 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2484 2485 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2486 } 2487 2488 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2489 const struct sctp_endpoint *ep, 2490 const struct sctp_association *asoc, 2491 const sctp_subtype_t type, 2492 void *arg, 2493 sctp_cmd_seq_t *commands) 2494 { 2495 struct sctp_chunk *chunk = arg; 2496 unsigned int len; 2497 __be16 error = SCTP_ERROR_NO_ERROR; 2498 2499 /* See if we have an error cause code in the chunk. */ 2500 len = ntohs(chunk->chunk_hdr->length); 2501 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2502 2503 sctp_errhdr_t *err; 2504 sctp_walk_errors(err, chunk->chunk_hdr); 2505 if ((void *)err != (void *)chunk->chunk_end) 2506 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2507 2508 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2509 } 2510 2511 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2512 /* ASSOC_FAILED will DELETE_TCB. */ 2513 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2514 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2515 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2516 2517 return SCTP_DISPOSITION_ABORT; 2518 } 2519 2520 /* 2521 * Process an ABORT. (COOKIE-WAIT state) 2522 * 2523 * See sctp_sf_do_9_1_abort() above. 2524 */ 2525 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2526 const struct sctp_endpoint *ep, 2527 const struct sctp_association *asoc, 2528 const sctp_subtype_t type, 2529 void *arg, 2530 sctp_cmd_seq_t *commands) 2531 { 2532 struct sctp_chunk *chunk = arg; 2533 unsigned int len; 2534 __be16 error = SCTP_ERROR_NO_ERROR; 2535 2536 if (!sctp_vtag_verify_either(chunk, asoc)) 2537 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2538 2539 /* Make sure that the ABORT chunk has a valid length. 2540 * Since this is an ABORT chunk, we have to discard it 2541 * because of the following text: 2542 * RFC 2960, Section 3.3.7 2543 * If an endpoint receives an ABORT with a format error or for an 2544 * association that doesn't exist, it MUST silently discard it. 2545 * Because the length is "invalid", we can't really discard just 2546 * as we do not know its true length. So, to be safe, discard the 2547 * packet. 2548 */ 2549 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2550 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2551 2552 /* See if we have an error cause code in the chunk. */ 2553 len = ntohs(chunk->chunk_hdr->length); 2554 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2555 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2556 2557 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2558 chunk->transport); 2559 } 2560 2561 /* 2562 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2563 */ 2564 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2565 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 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2572 ENOPROTOOPT, asoc, 2573 (struct sctp_transport *)arg); 2574 } 2575 2576 /* 2577 * Process an ABORT. (COOKIE-ECHOED state) 2578 */ 2579 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2580 const struct sctp_endpoint *ep, 2581 const struct sctp_association *asoc, 2582 const sctp_subtype_t type, 2583 void *arg, 2584 sctp_cmd_seq_t *commands) 2585 { 2586 /* There is a single T1 timer, so we should be able to use 2587 * common function with the COOKIE-WAIT state. 2588 */ 2589 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2590 } 2591 2592 /* 2593 * Stop T1 timer and abort association with "INIT failed". 2594 * 2595 * This is common code called by several sctp_sf_*_abort() functions above. 2596 */ 2597 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2598 sctp_cmd_seq_t *commands, 2599 __be16 error, int sk_err, 2600 const struct sctp_association *asoc, 2601 struct sctp_transport *transport) 2602 { 2603 pr_debug("%s: ABORT received (INIT)\n", __func__); 2604 2605 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2606 SCTP_STATE(SCTP_STATE_CLOSED)); 2607 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2608 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2609 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2610 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2611 /* CMD_INIT_FAILED will DELETE_TCB. */ 2612 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2613 SCTP_PERR(error)); 2614 2615 return SCTP_DISPOSITION_ABORT; 2616 } 2617 2618 /* 2619 * sctp_sf_do_9_2_shut 2620 * 2621 * Section: 9.2 2622 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2623 * - enter the SHUTDOWN-RECEIVED state, 2624 * 2625 * - stop accepting new data from its SCTP user 2626 * 2627 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2628 * that all its outstanding DATA chunks have been received by the 2629 * SHUTDOWN sender. 2630 * 2631 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2632 * send a SHUTDOWN in response to a ULP request. And should discard 2633 * subsequent SHUTDOWN chunks. 2634 * 2635 * If there are still outstanding DATA chunks left, the SHUTDOWN 2636 * receiver shall continue to follow normal data transmission 2637 * procedures defined in Section 6 until all outstanding DATA chunks 2638 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2639 * new data from its SCTP user. 2640 * 2641 * Verification Tag: 8.5 Verification Tag [Normal verification] 2642 * 2643 * Inputs 2644 * (endpoint, asoc, chunk) 2645 * 2646 * Outputs 2647 * (asoc, reply_msg, msg_up, timers, counters) 2648 * 2649 * The return value is the disposition of the chunk. 2650 */ 2651 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2652 const struct sctp_endpoint *ep, 2653 const struct sctp_association *asoc, 2654 const sctp_subtype_t type, 2655 void *arg, 2656 sctp_cmd_seq_t *commands) 2657 { 2658 struct sctp_chunk *chunk = arg; 2659 sctp_shutdownhdr_t *sdh; 2660 sctp_disposition_t disposition; 2661 struct sctp_ulpevent *ev; 2662 __u32 ctsn; 2663 2664 if (!sctp_vtag_verify(chunk, asoc)) 2665 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2666 2667 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2668 if (!sctp_chunk_length_valid(chunk, 2669 sizeof(struct sctp_shutdown_chunk_t))) 2670 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2671 commands); 2672 2673 /* Convert the elaborate header. */ 2674 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2675 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2676 chunk->subh.shutdown_hdr = sdh; 2677 ctsn = ntohl(sdh->cum_tsn_ack); 2678 2679 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2680 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2681 asoc->ctsn_ack_point); 2682 2683 return SCTP_DISPOSITION_DISCARD; 2684 } 2685 2686 /* If Cumulative TSN Ack beyond the max tsn currently 2687 * send, terminating the association and respond to the 2688 * sender with an ABORT. 2689 */ 2690 if (!TSN_lt(ctsn, asoc->next_tsn)) 2691 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2692 2693 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2694 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2695 * inform the application that it should cease sending data. 2696 */ 2697 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2698 if (!ev) { 2699 disposition = SCTP_DISPOSITION_NOMEM; 2700 goto out; 2701 } 2702 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2703 2704 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2705 * - enter the SHUTDOWN-RECEIVED state, 2706 * - stop accepting new data from its SCTP user 2707 * 2708 * [This is implicit in the new state.] 2709 */ 2710 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2711 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2712 disposition = SCTP_DISPOSITION_CONSUME; 2713 2714 if (sctp_outq_is_empty(&asoc->outqueue)) { 2715 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2716 arg, commands); 2717 } 2718 2719 if (SCTP_DISPOSITION_NOMEM == disposition) 2720 goto out; 2721 2722 /* - verify, by checking the Cumulative TSN Ack field of the 2723 * chunk, that all its outstanding DATA chunks have been 2724 * received by the SHUTDOWN sender. 2725 */ 2726 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2727 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2728 2729 out: 2730 return disposition; 2731 } 2732 2733 /* 2734 * sctp_sf_do_9_2_shut_ctsn 2735 * 2736 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2737 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2738 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2739 * MUST be processed. 2740 */ 2741 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2742 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 sctp_shutdownhdr_t *sdh; 2750 __u32 ctsn; 2751 2752 if (!sctp_vtag_verify(chunk, asoc)) 2753 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2754 2755 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2756 if (!sctp_chunk_length_valid(chunk, 2757 sizeof(struct sctp_shutdown_chunk_t))) 2758 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2759 commands); 2760 2761 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2762 ctsn = ntohl(sdh->cum_tsn_ack); 2763 2764 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2765 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2766 asoc->ctsn_ack_point); 2767 2768 return SCTP_DISPOSITION_DISCARD; 2769 } 2770 2771 /* If Cumulative TSN Ack beyond the max tsn currently 2772 * send, terminating the association and respond to the 2773 * sender with an ABORT. 2774 */ 2775 if (!TSN_lt(ctsn, asoc->next_tsn)) 2776 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2777 2778 /* verify, by checking the Cumulative TSN Ack field of the 2779 * chunk, that all its outstanding DATA chunks have been 2780 * received by the SHUTDOWN sender. 2781 */ 2782 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2783 SCTP_BE32(sdh->cum_tsn_ack)); 2784 2785 return SCTP_DISPOSITION_CONSUME; 2786 } 2787 2788 /* RFC 2960 9.2 2789 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2790 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2791 * transport addresses (either in the IP addresses or in the INIT chunk) 2792 * that belong to this association, it should discard the INIT chunk and 2793 * retransmit the SHUTDOWN ACK chunk. 2794 */ 2795 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2796 const struct sctp_endpoint *ep, 2797 const struct sctp_association *asoc, 2798 const sctp_subtype_t type, 2799 void *arg, 2800 sctp_cmd_seq_t *commands) 2801 { 2802 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2803 struct sctp_chunk *reply; 2804 2805 /* Make sure that the chunk has a valid length */ 2806 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2807 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2808 commands); 2809 2810 /* Since we are not going to really process this INIT, there 2811 * is no point in verifying chunk boundries. Just generate 2812 * the SHUTDOWN ACK. 2813 */ 2814 reply = sctp_make_shutdown_ack(asoc, chunk); 2815 if (NULL == reply) 2816 goto nomem; 2817 2818 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2819 * the T2-SHUTDOWN timer. 2820 */ 2821 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2822 2823 /* and restart the T2-shutdown timer. */ 2824 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2825 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2826 2827 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2828 2829 return SCTP_DISPOSITION_CONSUME; 2830 nomem: 2831 return SCTP_DISPOSITION_NOMEM; 2832 } 2833 2834 /* 2835 * sctp_sf_do_ecn_cwr 2836 * 2837 * Section: Appendix A: Explicit Congestion Notification 2838 * 2839 * CWR: 2840 * 2841 * RFC 2481 details a specific bit for a sender to send in the header of 2842 * its next outbound TCP segment to indicate to its peer that it has 2843 * reduced its congestion window. This is termed the CWR bit. For 2844 * SCTP the same indication is made by including the CWR chunk. 2845 * This chunk contains one data element, i.e. the TSN number that 2846 * was sent in the ECNE chunk. This element represents the lowest 2847 * TSN number in the datagram that was originally marked with the 2848 * CE bit. 2849 * 2850 * Verification Tag: 8.5 Verification Tag [Normal verification] 2851 * Inputs 2852 * (endpoint, asoc, chunk) 2853 * 2854 * Outputs 2855 * (asoc, reply_msg, msg_up, timers, counters) 2856 * 2857 * The return value is the disposition of the chunk. 2858 */ 2859 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2860 const struct sctp_endpoint *ep, 2861 const struct sctp_association *asoc, 2862 const sctp_subtype_t type, 2863 void *arg, 2864 sctp_cmd_seq_t *commands) 2865 { 2866 sctp_cwrhdr_t *cwr; 2867 struct sctp_chunk *chunk = arg; 2868 u32 lowest_tsn; 2869 2870 if (!sctp_vtag_verify(chunk, asoc)) 2871 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2872 2873 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2874 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2875 commands); 2876 2877 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2878 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2879 2880 lowest_tsn = ntohl(cwr->lowest_tsn); 2881 2882 /* Does this CWR ack the last sent congestion notification? */ 2883 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2884 /* Stop sending ECNE. */ 2885 sctp_add_cmd_sf(commands, 2886 SCTP_CMD_ECN_CWR, 2887 SCTP_U32(lowest_tsn)); 2888 } 2889 return SCTP_DISPOSITION_CONSUME; 2890 } 2891 2892 /* 2893 * sctp_sf_do_ecne 2894 * 2895 * Section: Appendix A: Explicit Congestion Notification 2896 * 2897 * ECN-Echo 2898 * 2899 * RFC 2481 details a specific bit for a receiver to send back in its 2900 * TCP acknowledgements to notify the sender of the Congestion 2901 * Experienced (CE) bit having arrived from the network. For SCTP this 2902 * same indication is made by including the ECNE chunk. This chunk 2903 * contains one data element, i.e. the lowest TSN associated with the IP 2904 * datagram marked with the CE bit..... 2905 * 2906 * Verification Tag: 8.5 Verification Tag [Normal verification] 2907 * Inputs 2908 * (endpoint, asoc, chunk) 2909 * 2910 * Outputs 2911 * (asoc, reply_msg, msg_up, timers, counters) 2912 * 2913 * The return value is the disposition of the chunk. 2914 */ 2915 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2916 const struct sctp_endpoint *ep, 2917 const struct sctp_association *asoc, 2918 const sctp_subtype_t type, 2919 void *arg, 2920 sctp_cmd_seq_t *commands) 2921 { 2922 sctp_ecnehdr_t *ecne; 2923 struct sctp_chunk *chunk = arg; 2924 2925 if (!sctp_vtag_verify(chunk, asoc)) 2926 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2927 2928 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2929 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2930 commands); 2931 2932 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2933 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2934 2935 /* If this is a newer ECNE than the last CWR packet we sent out */ 2936 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2937 SCTP_U32(ntohl(ecne->lowest_tsn))); 2938 2939 return SCTP_DISPOSITION_CONSUME; 2940 } 2941 2942 /* 2943 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2944 * 2945 * The SCTP endpoint MUST always acknowledge the reception of each valid 2946 * DATA chunk. 2947 * 2948 * The guidelines on delayed acknowledgement algorithm specified in 2949 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2950 * acknowledgement SHOULD be generated for at least every second packet 2951 * (not every second DATA chunk) received, and SHOULD be generated within 2952 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2953 * situations it may be beneficial for an SCTP transmitter to be more 2954 * conservative than the algorithms detailed in this document allow. 2955 * However, an SCTP transmitter MUST NOT be more aggressive than the 2956 * following algorithms allow. 2957 * 2958 * A SCTP receiver MUST NOT generate more than one SACK for every 2959 * incoming packet, other than to update the offered window as the 2960 * receiving application consumes new data. 2961 * 2962 * Verification Tag: 8.5 Verification Tag [Normal verification] 2963 * 2964 * Inputs 2965 * (endpoint, asoc, chunk) 2966 * 2967 * Outputs 2968 * (asoc, reply_msg, msg_up, timers, counters) 2969 * 2970 * The return value is the disposition of the chunk. 2971 */ 2972 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2973 const struct sctp_endpoint *ep, 2974 const struct sctp_association *asoc, 2975 const sctp_subtype_t type, 2976 void *arg, 2977 sctp_cmd_seq_t *commands) 2978 { 2979 struct sctp_chunk *chunk = arg; 2980 sctp_arg_t force = SCTP_NOFORCE(); 2981 int error; 2982 2983 if (!sctp_vtag_verify(chunk, asoc)) { 2984 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2985 SCTP_NULL()); 2986 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2987 } 2988 2989 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2990 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2991 commands); 2992 2993 error = sctp_eat_data(asoc, chunk, commands); 2994 switch (error) { 2995 case SCTP_IERROR_NO_ERROR: 2996 break; 2997 case SCTP_IERROR_HIGH_TSN: 2998 case SCTP_IERROR_BAD_STREAM: 2999 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3000 goto discard_noforce; 3001 case SCTP_IERROR_DUP_TSN: 3002 case SCTP_IERROR_IGNORE_TSN: 3003 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3004 goto discard_force; 3005 case SCTP_IERROR_NO_DATA: 3006 return SCTP_DISPOSITION_ABORT; 3007 case SCTP_IERROR_PROTO_VIOLATION: 3008 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3009 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3010 default: 3011 BUG(); 3012 } 3013 3014 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3015 force = SCTP_FORCE(); 3016 3017 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3018 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3019 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3020 } 3021 3022 /* If this is the last chunk in a packet, we need to count it 3023 * toward sack generation. Note that we need to SACK every 3024 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3025 * THEM. We elect to NOT generate SACK's if the chunk fails 3026 * the verification tag test. 3027 * 3028 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3029 * 3030 * The SCTP endpoint MUST always acknowledge the reception of 3031 * each valid DATA chunk. 3032 * 3033 * The guidelines on delayed acknowledgement algorithm 3034 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3035 * Specifically, an acknowledgement SHOULD be generated for at 3036 * least every second packet (not every second DATA chunk) 3037 * received, and SHOULD be generated within 200 ms of the 3038 * arrival of any unacknowledged DATA chunk. In some 3039 * situations it may be beneficial for an SCTP transmitter to 3040 * be more conservative than the algorithms detailed in this 3041 * document allow. However, an SCTP transmitter MUST NOT be 3042 * more aggressive than the following algorithms allow. 3043 */ 3044 if (chunk->end_of_packet) 3045 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3046 3047 return SCTP_DISPOSITION_CONSUME; 3048 3049 discard_force: 3050 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3051 * 3052 * When a packet arrives with duplicate DATA chunk(s) and with 3053 * no new DATA chunk(s), the endpoint MUST immediately send a 3054 * SACK with no delay. If a packet arrives with duplicate 3055 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3056 * MAY immediately send a SACK. Normally receipt of duplicate 3057 * DATA chunks will occur when the original SACK chunk was lost 3058 * and the peer's RTO has expired. The duplicate TSN number(s) 3059 * SHOULD be reported in the SACK as duplicate. 3060 */ 3061 /* In our case, we split the MAY SACK advice up whether or not 3062 * the last chunk is a duplicate.' 3063 */ 3064 if (chunk->end_of_packet) 3065 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3066 return SCTP_DISPOSITION_DISCARD; 3067 3068 discard_noforce: 3069 if (chunk->end_of_packet) 3070 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3071 3072 return SCTP_DISPOSITION_DISCARD; 3073 } 3074 3075 /* 3076 * sctp_sf_eat_data_fast_4_4 3077 * 3078 * Section: 4 (4) 3079 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3080 * DATA chunks without delay. 3081 * 3082 * Verification Tag: 8.5 Verification Tag [Normal verification] 3083 * Inputs 3084 * (endpoint, asoc, chunk) 3085 * 3086 * Outputs 3087 * (asoc, reply_msg, msg_up, timers, counters) 3088 * 3089 * The return value is the disposition of the chunk. 3090 */ 3091 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3092 const struct sctp_endpoint *ep, 3093 const struct sctp_association *asoc, 3094 const sctp_subtype_t type, 3095 void *arg, 3096 sctp_cmd_seq_t *commands) 3097 { 3098 struct sctp_chunk *chunk = arg; 3099 int error; 3100 3101 if (!sctp_vtag_verify(chunk, asoc)) { 3102 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3103 SCTP_NULL()); 3104 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3105 } 3106 3107 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3108 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3109 commands); 3110 3111 error = sctp_eat_data(asoc, chunk, commands); 3112 switch (error) { 3113 case SCTP_IERROR_NO_ERROR: 3114 case SCTP_IERROR_HIGH_TSN: 3115 case SCTP_IERROR_DUP_TSN: 3116 case SCTP_IERROR_IGNORE_TSN: 3117 case SCTP_IERROR_BAD_STREAM: 3118 break; 3119 case SCTP_IERROR_NO_DATA: 3120 return SCTP_DISPOSITION_ABORT; 3121 case SCTP_IERROR_PROTO_VIOLATION: 3122 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3123 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3124 default: 3125 BUG(); 3126 } 3127 3128 /* Go a head and force a SACK, since we are shutting down. */ 3129 3130 /* Implementor's Guide. 3131 * 3132 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3133 * respond to each received packet containing one or more DATA chunk(s) 3134 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3135 */ 3136 if (chunk->end_of_packet) { 3137 /* We must delay the chunk creation since the cumulative 3138 * TSN has not been updated yet. 3139 */ 3140 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3141 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3142 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3143 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3144 } 3145 3146 return SCTP_DISPOSITION_CONSUME; 3147 } 3148 3149 /* 3150 * Section: 6.2 Processing a Received SACK 3151 * D) Any time a SACK arrives, the endpoint performs the following: 3152 * 3153 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3154 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3155 * increasing, a SACK whose Cumulative TSN Ack is less than the 3156 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3157 * 3158 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3159 * of bytes still outstanding after processing the Cumulative TSN Ack 3160 * and the Gap Ack Blocks. 3161 * 3162 * iii) If the SACK is missing a TSN that was previously 3163 * acknowledged via a Gap Ack Block (e.g., the data receiver 3164 * reneged on the data), then mark the corresponding DATA chunk 3165 * as available for retransmit: Mark it as missing for fast 3166 * retransmit as described in Section 7.2.4 and if no retransmit 3167 * timer is running for the destination address to which the DATA 3168 * chunk was originally transmitted, then T3-rtx is started for 3169 * that destination address. 3170 * 3171 * Verification Tag: 8.5 Verification Tag [Normal verification] 3172 * 3173 * Inputs 3174 * (endpoint, asoc, chunk) 3175 * 3176 * Outputs 3177 * (asoc, reply_msg, msg_up, timers, counters) 3178 * 3179 * The return value is the disposition of the chunk. 3180 */ 3181 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3182 const struct sctp_endpoint *ep, 3183 const struct sctp_association *asoc, 3184 const sctp_subtype_t type, 3185 void *arg, 3186 sctp_cmd_seq_t *commands) 3187 { 3188 struct sctp_chunk *chunk = arg; 3189 sctp_sackhdr_t *sackh; 3190 __u32 ctsn; 3191 3192 if (!sctp_vtag_verify(chunk, asoc)) 3193 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3194 3195 /* Make sure that the SACK chunk has a valid length. */ 3196 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3197 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3198 commands); 3199 3200 /* Pull the SACK chunk from the data buffer */ 3201 sackh = sctp_sm_pull_sack(chunk); 3202 /* Was this a bogus SACK? */ 3203 if (!sackh) 3204 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3205 chunk->subh.sack_hdr = sackh; 3206 ctsn = ntohl(sackh->cum_tsn_ack); 3207 3208 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3209 * Ack Point, then drop the SACK. Since Cumulative TSN 3210 * Ack is monotonically increasing, a SACK whose 3211 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3212 * Point indicates an out-of-order SACK. 3213 */ 3214 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3215 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3216 asoc->ctsn_ack_point); 3217 3218 return SCTP_DISPOSITION_DISCARD; 3219 } 3220 3221 /* If Cumulative TSN Ack beyond the max tsn currently 3222 * send, terminating the association and respond to the 3223 * sender with an ABORT. 3224 */ 3225 if (!TSN_lt(ctsn, asoc->next_tsn)) 3226 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3227 3228 /* Return this SACK for further processing. */ 3229 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3230 3231 /* Note: We do the rest of the work on the PROCESS_SACK 3232 * sideeffect. 3233 */ 3234 return SCTP_DISPOSITION_CONSUME; 3235 } 3236 3237 /* 3238 * Generate an ABORT in response to a packet. 3239 * 3240 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3241 * 3242 * 8) The receiver should respond to the sender of the OOTB packet with 3243 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3244 * MUST fill in the Verification Tag field of the outbound packet 3245 * with the value found in the Verification Tag field of the OOTB 3246 * packet and set the T-bit in the Chunk Flags to indicate that the 3247 * Verification Tag is reflected. After sending this ABORT, the 3248 * receiver of the OOTB packet shall discard the OOTB packet and take 3249 * no further action. 3250 * 3251 * Verification Tag: 3252 * 3253 * The return value is the disposition of the chunk. 3254 */ 3255 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3256 const struct sctp_endpoint *ep, 3257 const struct sctp_association *asoc, 3258 const sctp_subtype_t type, 3259 void *arg, 3260 sctp_cmd_seq_t *commands) 3261 { 3262 struct sctp_packet *packet = NULL; 3263 struct sctp_chunk *chunk = arg; 3264 struct sctp_chunk *abort; 3265 3266 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3267 if (!packet) 3268 return SCTP_DISPOSITION_NOMEM; 3269 3270 /* Make an ABORT. The T bit will be set if the asoc 3271 * is NULL. 3272 */ 3273 abort = sctp_make_abort(asoc, chunk, 0); 3274 if (!abort) { 3275 sctp_ootb_pkt_free(packet); 3276 return SCTP_DISPOSITION_NOMEM; 3277 } 3278 3279 /* Reflect vtag if T-Bit is set */ 3280 if (sctp_test_T_bit(abort)) 3281 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3282 3283 /* Set the skb to the belonging sock for accounting. */ 3284 abort->skb->sk = ep->base.sk; 3285 3286 sctp_packet_append_chunk(packet, abort); 3287 3288 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3289 SCTP_PACKET(packet)); 3290 3291 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3292 3293 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3294 return SCTP_DISPOSITION_CONSUME; 3295 } 3296 3297 /* 3298 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3299 * event as ULP notification for each cause included in the chunk. 3300 * 3301 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3302 * 3303 * The return value is the disposition of the chunk. 3304 */ 3305 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3306 const struct sctp_endpoint *ep, 3307 const struct sctp_association *asoc, 3308 const sctp_subtype_t type, 3309 void *arg, 3310 sctp_cmd_seq_t *commands) 3311 { 3312 struct sctp_chunk *chunk = arg; 3313 sctp_errhdr_t *err; 3314 3315 if (!sctp_vtag_verify(chunk, asoc)) 3316 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3317 3318 /* Make sure that the ERROR chunk has a valid length. */ 3319 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3320 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3321 commands); 3322 sctp_walk_errors(err, chunk->chunk_hdr); 3323 if ((void *)err != (void *)chunk->chunk_end) 3324 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3325 (void *)err, commands); 3326 3327 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3328 SCTP_CHUNK(chunk)); 3329 3330 return SCTP_DISPOSITION_CONSUME; 3331 } 3332 3333 /* 3334 * Process an inbound SHUTDOWN ACK. 3335 * 3336 * From Section 9.2: 3337 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3338 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3339 * peer, and remove all record of the association. 3340 * 3341 * The return value is the disposition. 3342 */ 3343 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3344 const struct sctp_endpoint *ep, 3345 const struct sctp_association *asoc, 3346 const sctp_subtype_t type, 3347 void *arg, 3348 sctp_cmd_seq_t *commands) 3349 { 3350 struct sctp_chunk *chunk = arg; 3351 struct sctp_chunk *reply; 3352 struct sctp_ulpevent *ev; 3353 3354 if (!sctp_vtag_verify(chunk, asoc)) 3355 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3356 3357 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3358 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3359 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3360 commands); 3361 /* 10.2 H) SHUTDOWN COMPLETE notification 3362 * 3363 * When SCTP completes the shutdown procedures (section 9.2) this 3364 * notification is passed to the upper layer. 3365 */ 3366 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3367 0, 0, 0, NULL, GFP_ATOMIC); 3368 if (!ev) 3369 goto nomem; 3370 3371 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3372 reply = sctp_make_shutdown_complete(asoc, chunk); 3373 if (!reply) 3374 goto nomem_chunk; 3375 3376 /* Do all the commands now (after allocation), so that we 3377 * have consistent state if memory allocation failes 3378 */ 3379 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3380 3381 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3382 * stop the T2-shutdown timer, 3383 */ 3384 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3385 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3386 3387 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3388 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3389 3390 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3391 SCTP_STATE(SCTP_STATE_CLOSED)); 3392 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3393 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3394 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3395 3396 /* ...and remove all record of the association. */ 3397 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3398 return SCTP_DISPOSITION_DELETE_TCB; 3399 3400 nomem_chunk: 3401 sctp_ulpevent_free(ev); 3402 nomem: 3403 return SCTP_DISPOSITION_NOMEM; 3404 } 3405 3406 /* 3407 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3408 * 3409 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3410 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3411 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3412 * packet must fill in the Verification Tag field of the outbound 3413 * packet with the Verification Tag received in the SHUTDOWN ACK and 3414 * set the T-bit in the Chunk Flags to indicate that the Verification 3415 * Tag is reflected. 3416 * 3417 * 8) The receiver should respond to the sender of the OOTB packet with 3418 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3419 * MUST fill in the Verification Tag field of the outbound packet 3420 * with the value found in the Verification Tag field of the OOTB 3421 * packet and set the T-bit in the Chunk Flags to indicate that the 3422 * Verification Tag is reflected. After sending this ABORT, the 3423 * receiver of the OOTB packet shall discard the OOTB packet and take 3424 * no further action. 3425 */ 3426 sctp_disposition_t sctp_sf_ootb(struct net *net, 3427 const struct sctp_endpoint *ep, 3428 const struct sctp_association *asoc, 3429 const sctp_subtype_t type, 3430 void *arg, 3431 sctp_cmd_seq_t *commands) 3432 { 3433 struct sctp_chunk *chunk = arg; 3434 struct sk_buff *skb = chunk->skb; 3435 sctp_chunkhdr_t *ch; 3436 sctp_errhdr_t *err; 3437 __u8 *ch_end; 3438 int ootb_shut_ack = 0; 3439 int ootb_cookie_ack = 0; 3440 3441 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3442 3443 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3444 do { 3445 /* Report violation if the chunk is less then minimal */ 3446 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3447 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3448 commands); 3449 3450 /* Report violation if chunk len overflows */ 3451 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3452 if (ch_end > skb_tail_pointer(skb)) 3453 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3454 commands); 3455 3456 /* Now that we know we at least have a chunk header, 3457 * do things that are type appropriate. 3458 */ 3459 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3460 ootb_shut_ack = 1; 3461 3462 /* RFC 2960, Section 3.3.7 3463 * Moreover, under any circumstances, an endpoint that 3464 * receives an ABORT MUST NOT respond to that ABORT by 3465 * sending an ABORT of its own. 3466 */ 3467 if (SCTP_CID_ABORT == ch->type) 3468 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3469 3470 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3471 * or a COOKIE ACK the SCTP Packet should be silently 3472 * discarded. 3473 */ 3474 3475 if (SCTP_CID_COOKIE_ACK == ch->type) 3476 ootb_cookie_ack = 1; 3477 3478 if (SCTP_CID_ERROR == ch->type) { 3479 sctp_walk_errors(err, ch) { 3480 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3481 ootb_cookie_ack = 1; 3482 break; 3483 } 3484 } 3485 } 3486 3487 ch = (sctp_chunkhdr_t *) ch_end; 3488 } while (ch_end < skb_tail_pointer(skb)); 3489 3490 if (ootb_shut_ack) 3491 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3492 else if (ootb_cookie_ack) 3493 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3494 else 3495 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3496 } 3497 3498 /* 3499 * Handle an "Out of the blue" SHUTDOWN ACK. 3500 * 3501 * Section: 8.4 5, sctpimpguide 2.41. 3502 * 3503 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3504 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3505 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3506 * packet must fill in the Verification Tag field of the outbound 3507 * packet with the Verification Tag received in the SHUTDOWN ACK and 3508 * set the T-bit in the Chunk Flags to indicate that the Verification 3509 * Tag is reflected. 3510 * 3511 * Inputs 3512 * (endpoint, asoc, type, arg, commands) 3513 * 3514 * Outputs 3515 * (sctp_disposition_t) 3516 * 3517 * The return value is the disposition of the chunk. 3518 */ 3519 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3520 const struct sctp_endpoint *ep, 3521 const struct sctp_association *asoc, 3522 const sctp_subtype_t type, 3523 void *arg, 3524 sctp_cmd_seq_t *commands) 3525 { 3526 struct sctp_packet *packet = NULL; 3527 struct sctp_chunk *chunk = arg; 3528 struct sctp_chunk *shut; 3529 3530 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3531 if (!packet) 3532 return SCTP_DISPOSITION_NOMEM; 3533 3534 /* Make an SHUTDOWN_COMPLETE. 3535 * The T bit will be set if the asoc is NULL. 3536 */ 3537 shut = sctp_make_shutdown_complete(asoc, chunk); 3538 if (!shut) { 3539 sctp_ootb_pkt_free(packet); 3540 return SCTP_DISPOSITION_NOMEM; 3541 } 3542 3543 /* Reflect vtag if T-Bit is set */ 3544 if (sctp_test_T_bit(shut)) 3545 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3546 3547 /* Set the skb to the belonging sock for accounting. */ 3548 shut->skb->sk = ep->base.sk; 3549 3550 sctp_packet_append_chunk(packet, shut); 3551 3552 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3553 SCTP_PACKET(packet)); 3554 3555 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3556 3557 /* If the chunk length is invalid, we don't want to process 3558 * the reset of the packet. 3559 */ 3560 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3561 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3562 3563 /* We need to discard the rest of the packet to prevent 3564 * potential bomming attacks from additional bundled chunks. 3565 * This is documented in SCTP Threats ID. 3566 */ 3567 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3568 } 3569 3570 /* 3571 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3572 * 3573 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3574 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3575 * procedures in section 8.4 SHOULD be followed, in other words it 3576 * should be treated as an Out Of The Blue packet. 3577 * [This means that we do NOT check the Verification Tag on these 3578 * chunks. --piggy ] 3579 * 3580 */ 3581 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3582 const struct sctp_endpoint *ep, 3583 const struct sctp_association *asoc, 3584 const sctp_subtype_t type, 3585 void *arg, 3586 sctp_cmd_seq_t *commands) 3587 { 3588 struct sctp_chunk *chunk = arg; 3589 3590 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3591 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3592 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3593 commands); 3594 3595 /* Although we do have an association in this case, it corresponds 3596 * to a restarted association. So the packet is treated as an OOTB 3597 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3598 * called with a NULL association. 3599 */ 3600 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3601 3602 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3603 } 3604 3605 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3606 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3607 const struct sctp_endpoint *ep, 3608 const struct sctp_association *asoc, 3609 const sctp_subtype_t type, void *arg, 3610 sctp_cmd_seq_t *commands) 3611 { 3612 struct sctp_chunk *chunk = arg; 3613 struct sctp_chunk *asconf_ack = NULL; 3614 struct sctp_paramhdr *err_param = NULL; 3615 sctp_addiphdr_t *hdr; 3616 __u32 serial; 3617 3618 if (!sctp_vtag_verify(chunk, asoc)) { 3619 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3620 SCTP_NULL()); 3621 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3622 } 3623 3624 /* ADD-IP: Section 4.1.1 3625 * This chunk MUST be sent in an authenticated way by using 3626 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3627 * is received unauthenticated it MUST be silently discarded as 3628 * described in [I-D.ietf-tsvwg-sctp-auth]. 3629 */ 3630 if (!net->sctp.addip_noauth && !chunk->auth) 3631 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3632 3633 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3634 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3635 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3636 commands); 3637 3638 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3639 serial = ntohl(hdr->serial); 3640 3641 /* Verify the ASCONF chunk before processing it. */ 3642 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3643 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3644 (void *)err_param, commands); 3645 3646 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3647 * the endpoint stored in a new association variable 3648 * 'Peer-Serial-Number'. 3649 */ 3650 if (serial == asoc->peer.addip_serial + 1) { 3651 /* If this is the first instance of ASCONF in the packet, 3652 * we can clean our old ASCONF-ACKs. 3653 */ 3654 if (!chunk->has_asconf) 3655 sctp_assoc_clean_asconf_ack_cache(asoc); 3656 3657 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3658 * expected, process the ASCONF as described below and after 3659 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3660 * the response packet and cache a copy of it (in the event it 3661 * later needs to be retransmitted). 3662 * 3663 * Essentially, do V1-V5. 3664 */ 3665 asconf_ack = sctp_process_asconf((struct sctp_association *) 3666 asoc, chunk); 3667 if (!asconf_ack) 3668 return SCTP_DISPOSITION_NOMEM; 3669 } else if (serial < asoc->peer.addip_serial + 1) { 3670 /* ADDIP 5.2 E2) 3671 * If the value found in the Sequence Number is less than the 3672 * ('Peer- Sequence-Number' + 1), simply skip to the next 3673 * ASCONF, and include in the outbound response packet 3674 * any previously cached ASCONF-ACK response that was 3675 * sent and saved that matches the Sequence Number of the 3676 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3677 * Chunk exists. This will occur when an older ASCONF 3678 * arrives out of order. In such a case, the receiver 3679 * should skip the ASCONF Chunk and not include ASCONF-ACK 3680 * Chunk for that chunk. 3681 */ 3682 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3683 if (!asconf_ack) 3684 return SCTP_DISPOSITION_DISCARD; 3685 3686 /* Reset the transport so that we select the correct one 3687 * this time around. This is to make sure that we don't 3688 * accidentally use a stale transport that's been removed. 3689 */ 3690 asconf_ack->transport = NULL; 3691 } else { 3692 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3693 * it must be either a stale packet or from an attacker. 3694 */ 3695 return SCTP_DISPOSITION_DISCARD; 3696 } 3697 3698 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3699 * containing the ASCONF-ACK Chunks MUST be the source address of 3700 * the SCTP packet that held the ASCONF Chunks. 3701 * 3702 * To do this properly, we'll set the destination address of the chunk 3703 * and at the transmit time, will try look up the transport to use. 3704 * Since ASCONFs may be bundled, the correct transport may not be 3705 * created until we process the entire packet, thus this workaround. 3706 */ 3707 asconf_ack->dest = chunk->source; 3708 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3709 if (asoc->new_transport) { 3710 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3711 ((struct sctp_association *)asoc)->new_transport = NULL; 3712 } 3713 3714 return SCTP_DISPOSITION_CONSUME; 3715 } 3716 3717 /* 3718 * ADDIP Section 4.3 General rules for address manipulation 3719 * When building TLV parameters for the ASCONF Chunk that will add or 3720 * delete IP addresses the D0 to D13 rules should be applied: 3721 */ 3722 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3723 const struct sctp_endpoint *ep, 3724 const struct sctp_association *asoc, 3725 const sctp_subtype_t type, void *arg, 3726 sctp_cmd_seq_t *commands) 3727 { 3728 struct sctp_chunk *asconf_ack = arg; 3729 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3730 struct sctp_chunk *abort; 3731 struct sctp_paramhdr *err_param = NULL; 3732 sctp_addiphdr_t *addip_hdr; 3733 __u32 sent_serial, rcvd_serial; 3734 3735 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3736 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3737 SCTP_NULL()); 3738 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3739 } 3740 3741 /* ADD-IP, Section 4.1.2: 3742 * This chunk MUST be sent in an authenticated way by using 3743 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3744 * is received unauthenticated it MUST be silently discarded as 3745 * described in [I-D.ietf-tsvwg-sctp-auth]. 3746 */ 3747 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3748 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3749 3750 /* Make sure that the ADDIP chunk has a valid length. */ 3751 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3752 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3753 commands); 3754 3755 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3756 rcvd_serial = ntohl(addip_hdr->serial); 3757 3758 /* Verify the ASCONF-ACK chunk before processing it. */ 3759 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3760 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3761 (void *)err_param, commands); 3762 3763 if (last_asconf) { 3764 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3765 sent_serial = ntohl(addip_hdr->serial); 3766 } else { 3767 sent_serial = asoc->addip_serial - 1; 3768 } 3769 3770 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3771 * equal to the next serial number to be used but no ASCONF chunk is 3772 * outstanding the endpoint MUST ABORT the association. Note that a 3773 * sequence number is greater than if it is no more than 2^^31-1 3774 * larger than the current sequence number (using serial arithmetic). 3775 */ 3776 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3777 !(asoc->addip_last_asconf)) { 3778 abort = sctp_make_abort(asoc, asconf_ack, 3779 sizeof(sctp_errhdr_t)); 3780 if (abort) { 3781 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3782 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3783 SCTP_CHUNK(abort)); 3784 } 3785 /* We are going to ABORT, so we might as well stop 3786 * processing the rest of the chunks in the packet. 3787 */ 3788 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3789 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3790 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3791 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3792 SCTP_ERROR(ECONNABORTED)); 3793 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3794 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3795 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3796 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3797 return SCTP_DISPOSITION_ABORT; 3798 } 3799 3800 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3801 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3802 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3803 3804 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3805 asconf_ack)) { 3806 /* Successfully processed ASCONF_ACK. We can 3807 * release the next asconf if we have one. 3808 */ 3809 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3810 SCTP_NULL()); 3811 return SCTP_DISPOSITION_CONSUME; 3812 } 3813 3814 abort = sctp_make_abort(asoc, asconf_ack, 3815 sizeof(sctp_errhdr_t)); 3816 if (abort) { 3817 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3818 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3819 SCTP_CHUNK(abort)); 3820 } 3821 /* We are going to ABORT, so we might as well stop 3822 * processing the rest of the chunks in the packet. 3823 */ 3824 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3825 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3826 SCTP_ERROR(ECONNABORTED)); 3827 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3828 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3829 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3830 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3831 return SCTP_DISPOSITION_ABORT; 3832 } 3833 3834 return SCTP_DISPOSITION_DISCARD; 3835 } 3836 3837 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 3838 sctp_disposition_t sctp_sf_do_reconf(struct net *net, 3839 const struct sctp_endpoint *ep, 3840 const struct sctp_association *asoc, 3841 const sctp_subtype_t type, void *arg, 3842 sctp_cmd_seq_t *commands) 3843 { 3844 struct sctp_paramhdr *err_param = NULL; 3845 struct sctp_chunk *chunk = arg; 3846 struct sctp_reconf_chunk *hdr; 3847 union sctp_params param; 3848 3849 if (!sctp_vtag_verify(chunk, asoc)) { 3850 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3851 SCTP_NULL()); 3852 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3853 } 3854 3855 /* Make sure that the RECONF chunk has a valid length. */ 3856 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 3857 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3858 commands); 3859 3860 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 3861 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3862 (void *)err_param, commands); 3863 3864 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 3865 sctp_walk_params(param, hdr, params) { 3866 struct sctp_chunk *reply = NULL; 3867 struct sctp_ulpevent *ev = NULL; 3868 3869 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 3870 reply = sctp_process_strreset_outreq( 3871 (struct sctp_association *)asoc, param, &ev); 3872 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 3873 reply = sctp_process_strreset_inreq( 3874 (struct sctp_association *)asoc, param, &ev); 3875 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 3876 reply = sctp_process_strreset_tsnreq( 3877 (struct sctp_association *)asoc, param, &ev); 3878 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 3879 reply = sctp_process_strreset_addstrm_out( 3880 (struct sctp_association *)asoc, param, &ev); 3881 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 3882 reply = sctp_process_strreset_addstrm_in( 3883 (struct sctp_association *)asoc, param, &ev); 3884 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 3885 reply = sctp_process_strreset_resp( 3886 (struct sctp_association *)asoc, param, &ev); 3887 3888 if (ev) 3889 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3890 SCTP_ULPEVENT(ev)); 3891 3892 if (reply) 3893 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3894 SCTP_CHUNK(reply)); 3895 } 3896 3897 return SCTP_DISPOSITION_CONSUME; 3898 } 3899 3900 /* 3901 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3902 * 3903 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3904 * its cumulative TSN point to the value carried in the FORWARD TSN 3905 * chunk, and then MUST further advance its cumulative TSN point locally 3906 * if possible. 3907 * After the above processing, the data receiver MUST stop reporting any 3908 * missing TSNs earlier than or equal to the new cumulative TSN point. 3909 * 3910 * Verification Tag: 8.5 Verification Tag [Normal verification] 3911 * 3912 * The return value is the disposition of the chunk. 3913 */ 3914 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3915 const struct sctp_endpoint *ep, 3916 const struct sctp_association *asoc, 3917 const sctp_subtype_t type, 3918 void *arg, 3919 sctp_cmd_seq_t *commands) 3920 { 3921 struct sctp_chunk *chunk = arg; 3922 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3923 struct sctp_fwdtsn_skip *skip; 3924 __u16 len; 3925 __u32 tsn; 3926 3927 if (!sctp_vtag_verify(chunk, asoc)) { 3928 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3929 SCTP_NULL()); 3930 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3931 } 3932 3933 if (!asoc->peer.prsctp_capable) 3934 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 3935 3936 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3937 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3938 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3939 commands); 3940 3941 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3942 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3943 len = ntohs(chunk->chunk_hdr->length); 3944 len -= sizeof(struct sctp_chunkhdr); 3945 skb_pull(chunk->skb, len); 3946 3947 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3948 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3949 3950 /* The TSN is too high--silently discard the chunk and count on it 3951 * getting retransmitted later. 3952 */ 3953 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3954 goto discard_noforce; 3955 3956 /* Silently discard the chunk if stream-id is not valid */ 3957 sctp_walk_fwdtsn(skip, chunk) { 3958 if (ntohs(skip->stream) >= asoc->stream->incnt) 3959 goto discard_noforce; 3960 } 3961 3962 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3963 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3964 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3965 SCTP_CHUNK(chunk)); 3966 3967 /* Count this as receiving DATA. */ 3968 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3969 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3970 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3971 } 3972 3973 /* FIXME: For now send a SACK, but DATA processing may 3974 * send another. 3975 */ 3976 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3977 3978 return SCTP_DISPOSITION_CONSUME; 3979 3980 discard_noforce: 3981 return SCTP_DISPOSITION_DISCARD; 3982 } 3983 3984 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3985 struct net *net, 3986 const struct sctp_endpoint *ep, 3987 const struct sctp_association *asoc, 3988 const sctp_subtype_t type, 3989 void *arg, 3990 sctp_cmd_seq_t *commands) 3991 { 3992 struct sctp_chunk *chunk = arg; 3993 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3994 struct sctp_fwdtsn_skip *skip; 3995 __u16 len; 3996 __u32 tsn; 3997 3998 if (!sctp_vtag_verify(chunk, asoc)) { 3999 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4000 SCTP_NULL()); 4001 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4002 } 4003 4004 if (!asoc->peer.prsctp_capable) 4005 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4006 4007 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4008 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 4009 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4010 commands); 4011 4012 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4013 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4014 len = ntohs(chunk->chunk_hdr->length); 4015 len -= sizeof(struct sctp_chunkhdr); 4016 skb_pull(chunk->skb, len); 4017 4018 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4019 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4020 4021 /* The TSN is too high--silently discard the chunk and count on it 4022 * getting retransmitted later. 4023 */ 4024 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4025 goto gen_shutdown; 4026 4027 /* Silently discard the chunk if stream-id is not valid */ 4028 sctp_walk_fwdtsn(skip, chunk) { 4029 if (ntohs(skip->stream) >= asoc->stream->incnt) 4030 goto gen_shutdown; 4031 } 4032 4033 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4034 if (len > sizeof(struct sctp_fwdtsn_hdr)) 4035 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4036 SCTP_CHUNK(chunk)); 4037 4038 /* Go a head and force a SACK, since we are shutting down. */ 4039 gen_shutdown: 4040 /* Implementor's Guide. 4041 * 4042 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4043 * respond to each received packet containing one or more DATA chunk(s) 4044 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4045 */ 4046 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4047 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4048 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4049 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4050 4051 return SCTP_DISPOSITION_CONSUME; 4052 } 4053 4054 /* 4055 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4056 * 4057 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4058 * Identifier field. If this algorithm was not specified by the 4059 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4060 * during association setup, the AUTH chunk and all chunks after it MUST 4061 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4062 * defined in Section 4.1. 4063 * 4064 * If an endpoint with no shared key receives a Shared Key Identifier 4065 * other than 0, it MUST silently discard all authenticated chunks. If 4066 * the endpoint has at least one endpoint pair shared key for the peer, 4067 * it MUST use the key specified by the Shared Key Identifier if a 4068 * key has been configured for that Shared Key Identifier. If no 4069 * endpoint pair shared key has been configured for that Shared Key 4070 * Identifier, all authenticated chunks MUST be silently discarded. 4071 * 4072 * Verification Tag: 8.5 Verification Tag [Normal verification] 4073 * 4074 * The return value is the disposition of the chunk. 4075 */ 4076 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 4077 const struct sctp_endpoint *ep, 4078 const struct sctp_association *asoc, 4079 const sctp_subtype_t type, 4080 struct sctp_chunk *chunk) 4081 { 4082 struct sctp_authhdr *auth_hdr; 4083 struct sctp_hmac *hmac; 4084 unsigned int sig_len; 4085 __u16 key_id; 4086 __u8 *save_digest; 4087 __u8 *digest; 4088 4089 /* Pull in the auth header, so we can do some more verification */ 4090 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4091 chunk->subh.auth_hdr = auth_hdr; 4092 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4093 4094 /* Make sure that we support the HMAC algorithm from the auth 4095 * chunk. 4096 */ 4097 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4098 return SCTP_IERROR_AUTH_BAD_HMAC; 4099 4100 /* Make sure that the provided shared key identifier has been 4101 * configured 4102 */ 4103 key_id = ntohs(auth_hdr->shkey_id); 4104 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4105 return SCTP_IERROR_AUTH_BAD_KEYID; 4106 4107 4108 /* Make sure that the length of the signature matches what 4109 * we expect. 4110 */ 4111 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4112 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4113 if (sig_len != hmac->hmac_len) 4114 return SCTP_IERROR_PROTO_VIOLATION; 4115 4116 /* Now that we've done validation checks, we can compute and 4117 * verify the hmac. The steps involved are: 4118 * 1. Save the digest from the chunk. 4119 * 2. Zero out the digest in the chunk. 4120 * 3. Compute the new digest 4121 * 4. Compare saved and new digests. 4122 */ 4123 digest = auth_hdr->hmac; 4124 skb_pull(chunk->skb, sig_len); 4125 4126 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4127 if (!save_digest) 4128 goto nomem; 4129 4130 memset(digest, 0, sig_len); 4131 4132 sctp_auth_calculate_hmac(asoc, chunk->skb, 4133 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4134 GFP_ATOMIC); 4135 4136 /* Discard the packet if the digests do not match */ 4137 if (memcmp(save_digest, digest, sig_len)) { 4138 kfree(save_digest); 4139 return SCTP_IERROR_BAD_SIG; 4140 } 4141 4142 kfree(save_digest); 4143 chunk->auth = 1; 4144 4145 return SCTP_IERROR_NO_ERROR; 4146 nomem: 4147 return SCTP_IERROR_NOMEM; 4148 } 4149 4150 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4151 const struct sctp_endpoint *ep, 4152 const struct sctp_association *asoc, 4153 const sctp_subtype_t type, 4154 void *arg, 4155 sctp_cmd_seq_t *commands) 4156 { 4157 struct sctp_authhdr *auth_hdr; 4158 struct sctp_chunk *chunk = arg; 4159 struct sctp_chunk *err_chunk; 4160 sctp_ierror_t error; 4161 4162 /* Make sure that the peer has AUTH capable */ 4163 if (!asoc->peer.auth_capable) 4164 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4165 4166 if (!sctp_vtag_verify(chunk, asoc)) { 4167 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4168 SCTP_NULL()); 4169 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4170 } 4171 4172 /* Make sure that the AUTH chunk has valid length. */ 4173 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4174 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4175 commands); 4176 4177 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4178 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4179 switch (error) { 4180 case SCTP_IERROR_AUTH_BAD_HMAC: 4181 /* Generate the ERROR chunk and discard the rest 4182 * of the packet 4183 */ 4184 err_chunk = sctp_make_op_error(asoc, chunk, 4185 SCTP_ERROR_UNSUP_HMAC, 4186 &auth_hdr->hmac_id, 4187 sizeof(__u16), 0); 4188 if (err_chunk) { 4189 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4190 SCTP_CHUNK(err_chunk)); 4191 } 4192 /* Fall Through */ 4193 case SCTP_IERROR_AUTH_BAD_KEYID: 4194 case SCTP_IERROR_BAD_SIG: 4195 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4196 4197 case SCTP_IERROR_PROTO_VIOLATION: 4198 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4199 commands); 4200 4201 case SCTP_IERROR_NOMEM: 4202 return SCTP_DISPOSITION_NOMEM; 4203 4204 default: /* Prevent gcc warnings */ 4205 break; 4206 } 4207 4208 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4209 struct sctp_ulpevent *ev; 4210 4211 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4212 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4213 4214 if (!ev) 4215 return -ENOMEM; 4216 4217 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4218 SCTP_ULPEVENT(ev)); 4219 } 4220 4221 return SCTP_DISPOSITION_CONSUME; 4222 } 4223 4224 /* 4225 * Process an unknown chunk. 4226 * 4227 * Section: 3.2. Also, 2.1 in the implementor's guide. 4228 * 4229 * Chunk Types are encoded such that the highest-order two bits specify 4230 * the action that must be taken if the processing endpoint does not 4231 * recognize the Chunk Type. 4232 * 4233 * 00 - Stop processing this SCTP packet and discard it, do not process 4234 * any further chunks within it. 4235 * 4236 * 01 - Stop processing this SCTP packet and discard it, do not process 4237 * any further chunks within it, and report the unrecognized 4238 * chunk in an 'Unrecognized Chunk Type'. 4239 * 4240 * 10 - Skip this chunk and continue processing. 4241 * 4242 * 11 - Skip this chunk and continue processing, but report in an ERROR 4243 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4244 * 4245 * The return value is the disposition of the chunk. 4246 */ 4247 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4248 const struct sctp_endpoint *ep, 4249 const struct sctp_association *asoc, 4250 const sctp_subtype_t type, 4251 void *arg, 4252 sctp_cmd_seq_t *commands) 4253 { 4254 struct sctp_chunk *unk_chunk = arg; 4255 struct sctp_chunk *err_chunk; 4256 sctp_chunkhdr_t *hdr; 4257 4258 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4259 4260 if (!sctp_vtag_verify(unk_chunk, asoc)) 4261 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4262 4263 /* Make sure that the chunk has a valid length. 4264 * Since we don't know the chunk type, we use a general 4265 * chunkhdr structure to make a comparison. 4266 */ 4267 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4268 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4269 commands); 4270 4271 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4272 case SCTP_CID_ACTION_DISCARD: 4273 /* Discard the packet. */ 4274 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4275 case SCTP_CID_ACTION_DISCARD_ERR: 4276 /* Generate an ERROR chunk as response. */ 4277 hdr = unk_chunk->chunk_hdr; 4278 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4279 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4280 SCTP_PAD4(ntohs(hdr->length)), 4281 0); 4282 if (err_chunk) { 4283 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4284 SCTP_CHUNK(err_chunk)); 4285 } 4286 4287 /* Discard the packet. */ 4288 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4289 return SCTP_DISPOSITION_CONSUME; 4290 case SCTP_CID_ACTION_SKIP: 4291 /* Skip the chunk. */ 4292 return SCTP_DISPOSITION_DISCARD; 4293 case SCTP_CID_ACTION_SKIP_ERR: 4294 /* Generate an ERROR chunk as response. */ 4295 hdr = unk_chunk->chunk_hdr; 4296 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4297 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4298 SCTP_PAD4(ntohs(hdr->length)), 4299 0); 4300 if (err_chunk) { 4301 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4302 SCTP_CHUNK(err_chunk)); 4303 } 4304 /* Skip the chunk. */ 4305 return SCTP_DISPOSITION_CONSUME; 4306 default: 4307 break; 4308 } 4309 4310 return SCTP_DISPOSITION_DISCARD; 4311 } 4312 4313 /* 4314 * Discard the chunk. 4315 * 4316 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4317 * [Too numerous to mention...] 4318 * Verification Tag: No verification needed. 4319 * Inputs 4320 * (endpoint, asoc, chunk) 4321 * 4322 * Outputs 4323 * (asoc, reply_msg, msg_up, timers, counters) 4324 * 4325 * The return value is the disposition of the chunk. 4326 */ 4327 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4328 const struct sctp_endpoint *ep, 4329 const struct sctp_association *asoc, 4330 const sctp_subtype_t type, 4331 void *arg, 4332 sctp_cmd_seq_t *commands) 4333 { 4334 struct sctp_chunk *chunk = arg; 4335 4336 /* Make sure that the chunk has a valid length. 4337 * Since we don't know the chunk type, we use a general 4338 * chunkhdr structure to make a comparison. 4339 */ 4340 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4341 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4342 commands); 4343 4344 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4345 4346 return SCTP_DISPOSITION_DISCARD; 4347 } 4348 4349 /* 4350 * Discard the whole packet. 4351 * 4352 * Section: 8.4 2) 4353 * 4354 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4355 * silently discard the OOTB packet and take no further action. 4356 * 4357 * Verification Tag: No verification necessary 4358 * 4359 * Inputs 4360 * (endpoint, asoc, chunk) 4361 * 4362 * Outputs 4363 * (asoc, reply_msg, msg_up, timers, counters) 4364 * 4365 * The return value is the disposition of the chunk. 4366 */ 4367 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4368 const struct sctp_endpoint *ep, 4369 const struct sctp_association *asoc, 4370 const sctp_subtype_t type, 4371 void *arg, 4372 sctp_cmd_seq_t *commands) 4373 { 4374 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4375 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4376 4377 return SCTP_DISPOSITION_CONSUME; 4378 } 4379 4380 4381 /* 4382 * The other end is violating protocol. 4383 * 4384 * Section: Not specified 4385 * Verification Tag: Not specified 4386 * Inputs 4387 * (endpoint, asoc, chunk) 4388 * 4389 * Outputs 4390 * (asoc, reply_msg, msg_up, timers, counters) 4391 * 4392 * We simply tag the chunk as a violation. The state machine will log 4393 * the violation and continue. 4394 */ 4395 sctp_disposition_t sctp_sf_violation(struct net *net, 4396 const struct sctp_endpoint *ep, 4397 const struct sctp_association *asoc, 4398 const sctp_subtype_t type, 4399 void *arg, 4400 sctp_cmd_seq_t *commands) 4401 { 4402 struct sctp_chunk *chunk = arg; 4403 4404 /* Make sure that the chunk has a valid length. */ 4405 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4406 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4407 commands); 4408 4409 return SCTP_DISPOSITION_VIOLATION; 4410 } 4411 4412 /* 4413 * Common function to handle a protocol violation. 4414 */ 4415 static sctp_disposition_t sctp_sf_abort_violation( 4416 struct net *net, 4417 const struct sctp_endpoint *ep, 4418 const struct sctp_association *asoc, 4419 void *arg, 4420 sctp_cmd_seq_t *commands, 4421 const __u8 *payload, 4422 const size_t paylen) 4423 { 4424 struct sctp_packet *packet = NULL; 4425 struct sctp_chunk *chunk = arg; 4426 struct sctp_chunk *abort = NULL; 4427 4428 /* SCTP-AUTH, Section 6.3: 4429 * It should be noted that if the receiver wants to tear 4430 * down an association in an authenticated way only, the 4431 * handling of malformed packets should not result in 4432 * tearing down the association. 4433 * 4434 * This means that if we only want to abort associations 4435 * in an authenticated way (i.e AUTH+ABORT), then we 4436 * can't destroy this association just because the packet 4437 * was malformed. 4438 */ 4439 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4440 goto discard; 4441 4442 /* Make the abort chunk. */ 4443 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4444 if (!abort) 4445 goto nomem; 4446 4447 if (asoc) { 4448 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4449 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4450 !asoc->peer.i.init_tag) { 4451 sctp_initack_chunk_t *initack; 4452 4453 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4454 if (!sctp_chunk_length_valid(chunk, 4455 sizeof(sctp_initack_chunk_t))) 4456 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4457 else { 4458 unsigned int inittag; 4459 4460 inittag = ntohl(initack->init_hdr.init_tag); 4461 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4462 SCTP_U32(inittag)); 4463 } 4464 } 4465 4466 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4467 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4468 4469 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4470 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4471 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4472 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4473 SCTP_ERROR(ECONNREFUSED)); 4474 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4475 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4476 } else { 4477 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4478 SCTP_ERROR(ECONNABORTED)); 4479 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4480 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4481 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4482 } 4483 } else { 4484 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4485 4486 if (!packet) 4487 goto nomem_pkt; 4488 4489 if (sctp_test_T_bit(abort)) 4490 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4491 4492 abort->skb->sk = ep->base.sk; 4493 4494 sctp_packet_append_chunk(packet, abort); 4495 4496 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4497 SCTP_PACKET(packet)); 4498 4499 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4500 } 4501 4502 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4503 4504 discard: 4505 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4506 return SCTP_DISPOSITION_ABORT; 4507 4508 nomem_pkt: 4509 sctp_chunk_free(abort); 4510 nomem: 4511 return SCTP_DISPOSITION_NOMEM; 4512 } 4513 4514 /* 4515 * Handle a protocol violation when the chunk length is invalid. 4516 * "Invalid" length is identified as smaller than the minimal length a 4517 * given chunk can be. For example, a SACK chunk has invalid length 4518 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4519 * 4520 * We inform the other end by sending an ABORT with a Protocol Violation 4521 * error code. 4522 * 4523 * Section: Not specified 4524 * Verification Tag: Nothing to do 4525 * Inputs 4526 * (endpoint, asoc, chunk) 4527 * 4528 * Outputs 4529 * (reply_msg, msg_up, counters) 4530 * 4531 * Generate an ABORT chunk and terminate the association. 4532 */ 4533 static sctp_disposition_t sctp_sf_violation_chunklen( 4534 struct net *net, 4535 const struct sctp_endpoint *ep, 4536 const struct sctp_association *asoc, 4537 const sctp_subtype_t type, 4538 void *arg, 4539 sctp_cmd_seq_t *commands) 4540 { 4541 static const char err_str[] = "The following chunk had invalid length:"; 4542 4543 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4544 sizeof(err_str)); 4545 } 4546 4547 /* 4548 * Handle a protocol violation when the parameter length is invalid. 4549 * If the length is smaller than the minimum length of a given parameter, 4550 * or accumulated length in multi parameters exceeds the end of the chunk, 4551 * the length is considered as invalid. 4552 */ 4553 static sctp_disposition_t sctp_sf_violation_paramlen( 4554 struct net *net, 4555 const struct sctp_endpoint *ep, 4556 const struct sctp_association *asoc, 4557 const sctp_subtype_t type, 4558 void *arg, void *ext, 4559 sctp_cmd_seq_t *commands) 4560 { 4561 struct sctp_chunk *chunk = arg; 4562 struct sctp_paramhdr *param = ext; 4563 struct sctp_chunk *abort = NULL; 4564 4565 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4566 goto discard; 4567 4568 /* Make the abort chunk. */ 4569 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4570 if (!abort) 4571 goto nomem; 4572 4573 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4574 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4575 4576 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4577 SCTP_ERROR(ECONNABORTED)); 4578 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4579 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4580 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4581 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4582 4583 discard: 4584 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4585 return SCTP_DISPOSITION_ABORT; 4586 nomem: 4587 return SCTP_DISPOSITION_NOMEM; 4588 } 4589 4590 /* Handle a protocol violation when the peer trying to advance the 4591 * cumulative tsn ack to a point beyond the max tsn currently sent. 4592 * 4593 * We inform the other end by sending an ABORT with a Protocol Violation 4594 * error code. 4595 */ 4596 static sctp_disposition_t sctp_sf_violation_ctsn( 4597 struct net *net, 4598 const struct sctp_endpoint *ep, 4599 const struct sctp_association *asoc, 4600 const sctp_subtype_t type, 4601 void *arg, 4602 sctp_cmd_seq_t *commands) 4603 { 4604 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4605 4606 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4607 sizeof(err_str)); 4608 } 4609 4610 /* Handle protocol violation of an invalid chunk bundling. For example, 4611 * when we have an association and we receive bundled INIT-ACK, or 4612 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4613 * statement from the specs. Additionally, there might be an attacker 4614 * on the path and we may not want to continue this communication. 4615 */ 4616 static sctp_disposition_t sctp_sf_violation_chunk( 4617 struct net *net, 4618 const struct sctp_endpoint *ep, 4619 const struct sctp_association *asoc, 4620 const sctp_subtype_t type, 4621 void *arg, 4622 sctp_cmd_seq_t *commands) 4623 { 4624 static const char err_str[] = "The following chunk violates protocol:"; 4625 4626 if (!asoc) 4627 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4628 4629 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4630 sizeof(err_str)); 4631 } 4632 /*************************************************************************** 4633 * These are the state functions for handling primitive (Section 10) events. 4634 ***************************************************************************/ 4635 /* 4636 * sctp_sf_do_prm_asoc 4637 * 4638 * Section: 10.1 ULP-to-SCTP 4639 * B) Associate 4640 * 4641 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4642 * outbound stream count) 4643 * -> association id [,destination transport addr list] [,outbound stream 4644 * count] 4645 * 4646 * This primitive allows the upper layer to initiate an association to a 4647 * specific peer endpoint. 4648 * 4649 * The peer endpoint shall be specified by one of the transport addresses 4650 * which defines the endpoint (see Section 1.4). If the local SCTP 4651 * instance has not been initialized, the ASSOCIATE is considered an 4652 * error. 4653 * [This is not relevant for the kernel implementation since we do all 4654 * initialization at boot time. It we hadn't initialized we wouldn't 4655 * get anywhere near this code.] 4656 * 4657 * An association id, which is a local handle to the SCTP association, 4658 * will be returned on successful establishment of the association. If 4659 * SCTP is not able to open an SCTP association with the peer endpoint, 4660 * an error is returned. 4661 * [In the kernel implementation, the struct sctp_association needs to 4662 * be created BEFORE causing this primitive to run.] 4663 * 4664 * Other association parameters may be returned, including the 4665 * complete destination transport addresses of the peer as well as the 4666 * outbound stream count of the local endpoint. One of the transport 4667 * address from the returned destination addresses will be selected by 4668 * the local endpoint as default primary path for sending SCTP packets 4669 * to this peer. The returned "destination transport addr list" can 4670 * be used by the ULP to change the default primary path or to force 4671 * sending a packet to a specific transport address. [All of this 4672 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4673 * function.] 4674 * 4675 * Mandatory attributes: 4676 * 4677 * o local SCTP instance name - obtained from the INITIALIZE operation. 4678 * [This is the argument asoc.] 4679 * o destination transport addr - specified as one of the transport 4680 * addresses of the peer endpoint with which the association is to be 4681 * established. 4682 * [This is asoc->peer.active_path.] 4683 * o outbound stream count - the number of outbound streams the ULP 4684 * would like to open towards this peer endpoint. 4685 * [BUG: This is not currently implemented.] 4686 * Optional attributes: 4687 * 4688 * None. 4689 * 4690 * The return value is a disposition. 4691 */ 4692 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4693 const struct sctp_endpoint *ep, 4694 const struct sctp_association *asoc, 4695 const sctp_subtype_t type, 4696 void *arg, 4697 sctp_cmd_seq_t *commands) 4698 { 4699 struct sctp_chunk *repl; 4700 struct sctp_association *my_asoc; 4701 4702 /* The comment below says that we enter COOKIE-WAIT AFTER 4703 * sending the INIT, but that doesn't actually work in our 4704 * implementation... 4705 */ 4706 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4707 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4708 4709 /* RFC 2960 5.1 Normal Establishment of an Association 4710 * 4711 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4712 * must provide its Verification Tag (Tag_A) in the Initiate 4713 * Tag field. Tag_A SHOULD be a random number in the range of 4714 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4715 */ 4716 4717 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4718 if (!repl) 4719 goto nomem; 4720 4721 /* Choose transport for INIT. */ 4722 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4723 SCTP_CHUNK(repl)); 4724 4725 /* Cast away the const modifier, as we want to just 4726 * rerun it through as a sideffect. 4727 */ 4728 my_asoc = (struct sctp_association *)asoc; 4729 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4730 4731 /* After sending the INIT, "A" starts the T1-init timer and 4732 * enters the COOKIE-WAIT state. 4733 */ 4734 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4735 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4736 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4737 return SCTP_DISPOSITION_CONSUME; 4738 4739 nomem: 4740 return SCTP_DISPOSITION_NOMEM; 4741 } 4742 4743 /* 4744 * Process the SEND primitive. 4745 * 4746 * Section: 10.1 ULP-to-SCTP 4747 * E) Send 4748 * 4749 * Format: SEND(association id, buffer address, byte count [,context] 4750 * [,stream id] [,life time] [,destination transport address] 4751 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4752 * -> result 4753 * 4754 * This is the main method to send user data via SCTP. 4755 * 4756 * Mandatory attributes: 4757 * 4758 * o association id - local handle to the SCTP association 4759 * 4760 * o buffer address - the location where the user message to be 4761 * transmitted is stored; 4762 * 4763 * o byte count - The size of the user data in number of bytes; 4764 * 4765 * Optional attributes: 4766 * 4767 * o context - an optional 32 bit integer that will be carried in the 4768 * sending failure notification to the ULP if the transportation of 4769 * this User Message fails. 4770 * 4771 * o stream id - to indicate which stream to send the data on. If not 4772 * specified, stream 0 will be used. 4773 * 4774 * o life time - specifies the life time of the user data. The user data 4775 * will not be sent by SCTP after the life time expires. This 4776 * parameter can be used to avoid efforts to transmit stale 4777 * user messages. SCTP notifies the ULP if the data cannot be 4778 * initiated to transport (i.e. sent to the destination via SCTP's 4779 * send primitive) within the life time variable. However, the 4780 * user data will be transmitted if SCTP has attempted to transmit a 4781 * chunk before the life time expired. 4782 * 4783 * o destination transport address - specified as one of the destination 4784 * transport addresses of the peer endpoint to which this packet 4785 * should be sent. Whenever possible, SCTP should use this destination 4786 * transport address for sending the packets, instead of the current 4787 * primary path. 4788 * 4789 * o unorder flag - this flag, if present, indicates that the user 4790 * would like the data delivered in an unordered fashion to the peer 4791 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4792 * message). 4793 * 4794 * o no-bundle flag - instructs SCTP not to bundle this user data with 4795 * other outbound DATA chunks. SCTP MAY still bundle even when 4796 * this flag is present, when faced with network congestion. 4797 * 4798 * o payload protocol-id - A 32 bit unsigned integer that is to be 4799 * passed to the peer indicating the type of payload protocol data 4800 * being transmitted. This value is passed as opaque data by SCTP. 4801 * 4802 * The return value is the disposition. 4803 */ 4804 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4805 const struct sctp_endpoint *ep, 4806 const struct sctp_association *asoc, 4807 const sctp_subtype_t type, 4808 void *arg, 4809 sctp_cmd_seq_t *commands) 4810 { 4811 struct sctp_datamsg *msg = arg; 4812 4813 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4814 return SCTP_DISPOSITION_CONSUME; 4815 } 4816 4817 /* 4818 * Process the SHUTDOWN primitive. 4819 * 4820 * Section: 10.1: 4821 * C) Shutdown 4822 * 4823 * Format: SHUTDOWN(association id) 4824 * -> result 4825 * 4826 * Gracefully closes an association. Any locally queued user data 4827 * will be delivered to the peer. The association will be terminated only 4828 * after the peer acknowledges all the SCTP packets sent. A success code 4829 * will be returned on successful termination of the association. If 4830 * attempting to terminate the association results in a failure, an error 4831 * code shall be returned. 4832 * 4833 * Mandatory attributes: 4834 * 4835 * o association id - local handle to the SCTP association 4836 * 4837 * Optional attributes: 4838 * 4839 * None. 4840 * 4841 * The return value is the disposition. 4842 */ 4843 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4844 struct net *net, 4845 const struct sctp_endpoint *ep, 4846 const struct sctp_association *asoc, 4847 const sctp_subtype_t type, 4848 void *arg, 4849 sctp_cmd_seq_t *commands) 4850 { 4851 int disposition; 4852 4853 /* From 9.2 Shutdown of an Association 4854 * Upon receipt of the SHUTDOWN primitive from its upper 4855 * layer, the endpoint enters SHUTDOWN-PENDING state and 4856 * remains there until all outstanding data has been 4857 * acknowledged by its peer. The endpoint accepts no new data 4858 * from its upper layer, but retransmits data to the far end 4859 * if necessary to fill gaps. 4860 */ 4861 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4862 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4863 4864 disposition = SCTP_DISPOSITION_CONSUME; 4865 if (sctp_outq_is_empty(&asoc->outqueue)) { 4866 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4867 arg, commands); 4868 } 4869 return disposition; 4870 } 4871 4872 /* 4873 * Process the ABORT primitive. 4874 * 4875 * Section: 10.1: 4876 * C) Abort 4877 * 4878 * Format: Abort(association id [, cause code]) 4879 * -> result 4880 * 4881 * Ungracefully closes an association. Any locally queued user data 4882 * will be discarded and an ABORT chunk is sent to the peer. A success code 4883 * will be returned on successful abortion of the association. If 4884 * attempting to abort the association results in a failure, an error 4885 * code shall be returned. 4886 * 4887 * Mandatory attributes: 4888 * 4889 * o association id - local handle to the SCTP association 4890 * 4891 * Optional attributes: 4892 * 4893 * o cause code - reason of the abort to be passed to the peer 4894 * 4895 * None. 4896 * 4897 * The return value is the disposition. 4898 */ 4899 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4900 struct net *net, 4901 const struct sctp_endpoint *ep, 4902 const struct sctp_association *asoc, 4903 const sctp_subtype_t type, 4904 void *arg, 4905 sctp_cmd_seq_t *commands) 4906 { 4907 /* From 9.1 Abort of an Association 4908 * Upon receipt of the ABORT primitive from its upper 4909 * layer, the endpoint enters CLOSED state and 4910 * discard all outstanding data has been 4911 * acknowledged by its peer. The endpoint accepts no new data 4912 * from its upper layer, but retransmits data to the far end 4913 * if necessary to fill gaps. 4914 */ 4915 struct sctp_chunk *abort = arg; 4916 4917 if (abort) 4918 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4919 4920 /* Even if we can't send the ABORT due to low memory delete the 4921 * TCB. This is a departure from our typical NOMEM handling. 4922 */ 4923 4924 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4925 SCTP_ERROR(ECONNABORTED)); 4926 /* Delete the established association. */ 4927 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4928 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4929 4930 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4931 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4932 4933 return SCTP_DISPOSITION_ABORT; 4934 } 4935 4936 /* We tried an illegal operation on an association which is closed. */ 4937 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4938 const struct sctp_endpoint *ep, 4939 const struct sctp_association *asoc, 4940 const sctp_subtype_t type, 4941 void *arg, 4942 sctp_cmd_seq_t *commands) 4943 { 4944 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4945 return SCTP_DISPOSITION_CONSUME; 4946 } 4947 4948 /* We tried an illegal operation on an association which is shutting 4949 * down. 4950 */ 4951 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4952 const struct sctp_endpoint *ep, 4953 const struct sctp_association *asoc, 4954 const sctp_subtype_t type, 4955 void *arg, 4956 sctp_cmd_seq_t *commands) 4957 { 4958 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4959 SCTP_ERROR(-ESHUTDOWN)); 4960 return SCTP_DISPOSITION_CONSUME; 4961 } 4962 4963 /* 4964 * sctp_cookie_wait_prm_shutdown 4965 * 4966 * Section: 4 Note: 2 4967 * Verification Tag: 4968 * Inputs 4969 * (endpoint, asoc) 4970 * 4971 * The RFC does not explicitly address this issue, but is the route through the 4972 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4973 * 4974 * Outputs 4975 * (timers) 4976 */ 4977 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4978 struct net *net, 4979 const struct sctp_endpoint *ep, 4980 const struct sctp_association *asoc, 4981 const sctp_subtype_t type, 4982 void *arg, 4983 sctp_cmd_seq_t *commands) 4984 { 4985 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4986 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4987 4988 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4989 SCTP_STATE(SCTP_STATE_CLOSED)); 4990 4991 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4992 4993 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4994 4995 return SCTP_DISPOSITION_DELETE_TCB; 4996 } 4997 4998 /* 4999 * sctp_cookie_echoed_prm_shutdown 5000 * 5001 * Section: 4 Note: 2 5002 * Verification Tag: 5003 * Inputs 5004 * (endpoint, asoc) 5005 * 5006 * The RFC does not explcitly address this issue, but is the route through the 5007 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5008 * 5009 * Outputs 5010 * (timers) 5011 */ 5012 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 5013 struct net *net, 5014 const struct sctp_endpoint *ep, 5015 const struct sctp_association *asoc, 5016 const sctp_subtype_t type, 5017 void *arg, sctp_cmd_seq_t *commands) 5018 { 5019 /* There is a single T1 timer, so we should be able to use 5020 * common function with the COOKIE-WAIT state. 5021 */ 5022 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5023 } 5024 5025 /* 5026 * sctp_sf_cookie_wait_prm_abort 5027 * 5028 * Section: 4 Note: 2 5029 * Verification Tag: 5030 * Inputs 5031 * (endpoint, asoc) 5032 * 5033 * The RFC does not explicitly address this issue, but is the route through the 5034 * state table when someone issues an abort while in COOKIE_WAIT state. 5035 * 5036 * Outputs 5037 * (timers) 5038 */ 5039 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 5040 struct net *net, 5041 const struct sctp_endpoint *ep, 5042 const struct sctp_association *asoc, 5043 const sctp_subtype_t type, 5044 void *arg, 5045 sctp_cmd_seq_t *commands) 5046 { 5047 struct sctp_chunk *abort = arg; 5048 5049 /* Stop T1-init timer */ 5050 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5051 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5052 5053 if (abort) 5054 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5055 5056 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5057 SCTP_STATE(SCTP_STATE_CLOSED)); 5058 5059 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5060 5061 /* Even if we can't send the ABORT due to low memory delete the 5062 * TCB. This is a departure from our typical NOMEM handling. 5063 */ 5064 5065 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5066 SCTP_ERROR(ECONNREFUSED)); 5067 /* Delete the established association. */ 5068 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5069 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5070 5071 return SCTP_DISPOSITION_ABORT; 5072 } 5073 5074 /* 5075 * sctp_sf_cookie_echoed_prm_abort 5076 * 5077 * Section: 4 Note: 3 5078 * Verification Tag: 5079 * Inputs 5080 * (endpoint, asoc) 5081 * 5082 * The RFC does not explcitly address this issue, but is the route through the 5083 * state table when someone issues an abort while in COOKIE_ECHOED state. 5084 * 5085 * Outputs 5086 * (timers) 5087 */ 5088 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 5089 struct net *net, 5090 const struct sctp_endpoint *ep, 5091 const struct sctp_association *asoc, 5092 const sctp_subtype_t type, 5093 void *arg, 5094 sctp_cmd_seq_t *commands) 5095 { 5096 /* There is a single T1 timer, so we should be able to use 5097 * common function with the COOKIE-WAIT state. 5098 */ 5099 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5100 } 5101 5102 /* 5103 * sctp_sf_shutdown_pending_prm_abort 5104 * 5105 * Inputs 5106 * (endpoint, asoc) 5107 * 5108 * The RFC does not explicitly address this issue, but is the route through the 5109 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5110 * 5111 * Outputs 5112 * (timers) 5113 */ 5114 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5115 struct net *net, 5116 const struct sctp_endpoint *ep, 5117 const struct sctp_association *asoc, 5118 const sctp_subtype_t type, 5119 void *arg, 5120 sctp_cmd_seq_t *commands) 5121 { 5122 /* Stop the T5-shutdown guard timer. */ 5123 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5124 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5125 5126 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5127 } 5128 5129 /* 5130 * sctp_sf_shutdown_sent_prm_abort 5131 * 5132 * Inputs 5133 * (endpoint, asoc) 5134 * 5135 * The RFC does not explicitly address this issue, but is the route through the 5136 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5137 * 5138 * Outputs 5139 * (timers) 5140 */ 5141 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5142 struct net *net, 5143 const struct sctp_endpoint *ep, 5144 const struct sctp_association *asoc, 5145 const sctp_subtype_t type, 5146 void *arg, 5147 sctp_cmd_seq_t *commands) 5148 { 5149 /* Stop the T2-shutdown timer. */ 5150 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5151 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5152 5153 /* Stop the T5-shutdown guard timer. */ 5154 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5155 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5156 5157 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5158 } 5159 5160 /* 5161 * sctp_sf_cookie_echoed_prm_abort 5162 * 5163 * Inputs 5164 * (endpoint, asoc) 5165 * 5166 * The RFC does not explcitly address this issue, but is the route through the 5167 * state table when someone issues an abort while in COOKIE_ECHOED state. 5168 * 5169 * Outputs 5170 * (timers) 5171 */ 5172 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5173 struct net *net, 5174 const struct sctp_endpoint *ep, 5175 const struct sctp_association *asoc, 5176 const sctp_subtype_t type, 5177 void *arg, 5178 sctp_cmd_seq_t *commands) 5179 { 5180 /* The same T2 timer, so we should be able to use 5181 * common function with the SHUTDOWN-SENT state. 5182 */ 5183 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5184 } 5185 5186 /* 5187 * Process the REQUESTHEARTBEAT primitive 5188 * 5189 * 10.1 ULP-to-SCTP 5190 * J) Request Heartbeat 5191 * 5192 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5193 * 5194 * -> result 5195 * 5196 * Instructs the local endpoint to perform a HeartBeat on the specified 5197 * destination transport address of the given association. The returned 5198 * result should indicate whether the transmission of the HEARTBEAT 5199 * chunk to the destination address is successful. 5200 * 5201 * Mandatory attributes: 5202 * 5203 * o association id - local handle to the SCTP association 5204 * 5205 * o destination transport address - the transport address of the 5206 * association on which a heartbeat should be issued. 5207 */ 5208 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5209 struct net *net, 5210 const struct sctp_endpoint *ep, 5211 const struct sctp_association *asoc, 5212 const sctp_subtype_t type, 5213 void *arg, 5214 sctp_cmd_seq_t *commands) 5215 { 5216 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5217 (struct sctp_transport *)arg, commands)) 5218 return SCTP_DISPOSITION_NOMEM; 5219 5220 /* 5221 * RFC 2960 (bis), section 8.3 5222 * 5223 * D) Request an on-demand HEARTBEAT on a specific destination 5224 * transport address of a given association. 5225 * 5226 * The endpoint should increment the respective error counter of 5227 * the destination transport address each time a HEARTBEAT is sent 5228 * to that address and not acknowledged within one RTO. 5229 * 5230 */ 5231 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5232 SCTP_TRANSPORT(arg)); 5233 return SCTP_DISPOSITION_CONSUME; 5234 } 5235 5236 /* 5237 * ADDIP Section 4.1 ASCONF Chunk Procedures 5238 * When an endpoint has an ASCONF signaled change to be sent to the 5239 * remote endpoint it should do A1 to A9 5240 */ 5241 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5242 const struct sctp_endpoint *ep, 5243 const struct sctp_association *asoc, 5244 const sctp_subtype_t type, 5245 void *arg, 5246 sctp_cmd_seq_t *commands) 5247 { 5248 struct sctp_chunk *chunk = arg; 5249 5250 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5251 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5252 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5253 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5254 return SCTP_DISPOSITION_CONSUME; 5255 } 5256 5257 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5258 sctp_disposition_t sctp_sf_do_prm_reconf(struct net *net, 5259 const struct sctp_endpoint *ep, 5260 const struct sctp_association *asoc, 5261 const sctp_subtype_t type, 5262 void *arg, sctp_cmd_seq_t *commands) 5263 { 5264 struct sctp_chunk *chunk = arg; 5265 5266 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5267 return SCTP_DISPOSITION_CONSUME; 5268 } 5269 5270 /* 5271 * Ignore the primitive event 5272 * 5273 * The return value is the disposition of the primitive. 5274 */ 5275 sctp_disposition_t sctp_sf_ignore_primitive( 5276 struct net *net, 5277 const struct sctp_endpoint *ep, 5278 const struct sctp_association *asoc, 5279 const sctp_subtype_t type, 5280 void *arg, 5281 sctp_cmd_seq_t *commands) 5282 { 5283 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5284 type.primitive); 5285 5286 return SCTP_DISPOSITION_DISCARD; 5287 } 5288 5289 /*************************************************************************** 5290 * These are the state functions for the OTHER events. 5291 ***************************************************************************/ 5292 5293 /* 5294 * When the SCTP stack has no more user data to send or retransmit, this 5295 * notification is given to the user. Also, at the time when a user app 5296 * subscribes to this event, if there is no data to be sent or 5297 * retransmit, the stack will immediately send up this notification. 5298 */ 5299 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5300 struct net *net, 5301 const struct sctp_endpoint *ep, 5302 const struct sctp_association *asoc, 5303 const sctp_subtype_t type, 5304 void *arg, 5305 sctp_cmd_seq_t *commands) 5306 { 5307 struct sctp_ulpevent *event; 5308 5309 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5310 if (!event) 5311 return SCTP_DISPOSITION_NOMEM; 5312 5313 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5314 5315 return SCTP_DISPOSITION_CONSUME; 5316 } 5317 5318 /* 5319 * Start the shutdown negotiation. 5320 * 5321 * From Section 9.2: 5322 * Once all its outstanding data has been acknowledged, the endpoint 5323 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5324 * TSN Ack field the last sequential TSN it has received from the peer. 5325 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5326 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5327 * with the updated last sequential TSN received from its peer. 5328 * 5329 * The return value is the disposition. 5330 */ 5331 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5332 struct net *net, 5333 const struct sctp_endpoint *ep, 5334 const struct sctp_association *asoc, 5335 const sctp_subtype_t type, 5336 void *arg, 5337 sctp_cmd_seq_t *commands) 5338 { 5339 struct sctp_chunk *reply; 5340 5341 /* Once all its outstanding data has been acknowledged, the 5342 * endpoint shall send a SHUTDOWN chunk to its peer including 5343 * in the Cumulative TSN Ack field the last sequential TSN it 5344 * has received from the peer. 5345 */ 5346 reply = sctp_make_shutdown(asoc, NULL); 5347 if (!reply) 5348 goto nomem; 5349 5350 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5351 * T2-shutdown timer. 5352 */ 5353 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5354 5355 /* It shall then start the T2-shutdown timer */ 5356 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5357 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5358 5359 /* RFC 4960 Section 9.2 5360 * The sender of the SHUTDOWN MAY also start an overall guard timer 5361 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5362 */ 5363 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5364 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5365 5366 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5367 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5368 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5369 5370 /* and enter the SHUTDOWN-SENT state. */ 5371 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5372 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5373 5374 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5375 * 5376 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5377 * or SHUTDOWN-ACK. 5378 */ 5379 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5380 5381 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5382 5383 return SCTP_DISPOSITION_CONSUME; 5384 5385 nomem: 5386 return SCTP_DISPOSITION_NOMEM; 5387 } 5388 5389 /* 5390 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5391 * 5392 * From Section 9.2: 5393 * 5394 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5395 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5396 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5397 * endpoint must re-send the SHUTDOWN ACK. 5398 * 5399 * The return value is the disposition. 5400 */ 5401 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5402 struct net *net, 5403 const struct sctp_endpoint *ep, 5404 const struct sctp_association *asoc, 5405 const sctp_subtype_t type, 5406 void *arg, 5407 sctp_cmd_seq_t *commands) 5408 { 5409 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5410 struct sctp_chunk *reply; 5411 5412 /* There are 2 ways of getting here: 5413 * 1) called in response to a SHUTDOWN chunk 5414 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5415 * 5416 * For the case (2), the arg parameter is set to NULL. We need 5417 * to check that we have a chunk before accessing it's fields. 5418 */ 5419 if (chunk) { 5420 if (!sctp_vtag_verify(chunk, asoc)) 5421 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5422 5423 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5424 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5425 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5426 commands); 5427 } 5428 5429 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5430 * shall send a SHUTDOWN ACK ... 5431 */ 5432 reply = sctp_make_shutdown_ack(asoc, chunk); 5433 if (!reply) 5434 goto nomem; 5435 5436 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5437 * the T2-shutdown timer. 5438 */ 5439 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5440 5441 /* and start/restart a T2-shutdown timer of its own, */ 5442 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5443 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5444 5445 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5446 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5447 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5448 5449 /* Enter the SHUTDOWN-ACK-SENT state. */ 5450 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5451 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5452 5453 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5454 * 5455 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5456 * or SHUTDOWN-ACK. 5457 */ 5458 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5459 5460 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5461 5462 return SCTP_DISPOSITION_CONSUME; 5463 5464 nomem: 5465 return SCTP_DISPOSITION_NOMEM; 5466 } 5467 5468 /* 5469 * Ignore the event defined as other 5470 * 5471 * The return value is the disposition of the event. 5472 */ 5473 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5474 const struct sctp_endpoint *ep, 5475 const struct sctp_association *asoc, 5476 const sctp_subtype_t type, 5477 void *arg, 5478 sctp_cmd_seq_t *commands) 5479 { 5480 pr_debug("%s: the event other type:%d is ignored\n", 5481 __func__, type.other); 5482 5483 return SCTP_DISPOSITION_DISCARD; 5484 } 5485 5486 /************************************************************ 5487 * These are the state functions for handling timeout events. 5488 ************************************************************/ 5489 5490 /* 5491 * RTX Timeout 5492 * 5493 * Section: 6.3.3 Handle T3-rtx Expiration 5494 * 5495 * Whenever the retransmission timer T3-rtx expires for a destination 5496 * address, do the following: 5497 * [See below] 5498 * 5499 * The return value is the disposition of the chunk. 5500 */ 5501 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5502 const struct sctp_endpoint *ep, 5503 const struct sctp_association *asoc, 5504 const sctp_subtype_t type, 5505 void *arg, 5506 sctp_cmd_seq_t *commands) 5507 { 5508 struct sctp_transport *transport = arg; 5509 5510 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5511 5512 if (asoc->overall_error_count >= asoc->max_retrans) { 5513 if (asoc->peer.zero_window_announced && 5514 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5515 /* 5516 * We are here likely because the receiver had its rwnd 5517 * closed for a while and we have not been able to 5518 * transmit the locally queued data within the maximum 5519 * retransmission attempts limit. Start the T5 5520 * shutdown guard timer to give the receiver one last 5521 * chance and some additional time to recover before 5522 * aborting. 5523 */ 5524 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5525 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5526 } else { 5527 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5528 SCTP_ERROR(ETIMEDOUT)); 5529 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5530 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5531 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5532 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5533 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5534 return SCTP_DISPOSITION_DELETE_TCB; 5535 } 5536 } 5537 5538 /* E1) For the destination address for which the timer 5539 * expires, adjust its ssthresh with rules defined in Section 5540 * 7.2.3 and set the cwnd <- MTU. 5541 */ 5542 5543 /* E2) For the destination address for which the timer 5544 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5545 * maximum value discussed in rule C7 above (RTO.max) may be 5546 * used to provide an upper bound to this doubling operation. 5547 */ 5548 5549 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5550 * outstanding DATA chunks for the address for which the 5551 * T3-rtx has expired will fit into a single packet, subject 5552 * to the MTU constraint for the path corresponding to the 5553 * destination transport address to which the retransmission 5554 * is being sent (this may be different from the address for 5555 * which the timer expires [see Section 6.4]). Call this 5556 * value K. Bundle and retransmit those K DATA chunks in a 5557 * single packet to the destination endpoint. 5558 * 5559 * Note: Any DATA chunks that were sent to the address for 5560 * which the T3-rtx timer expired but did not fit in one MTU 5561 * (rule E3 above), should be marked for retransmission and 5562 * sent as soon as cwnd allows (normally when a SACK arrives). 5563 */ 5564 5565 /* Do some failure management (Section 8.2). */ 5566 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5567 5568 /* NB: Rules E4 and F1 are implicit in R1. */ 5569 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5570 5571 return SCTP_DISPOSITION_CONSUME; 5572 } 5573 5574 /* 5575 * Generate delayed SACK on timeout 5576 * 5577 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5578 * 5579 * The guidelines on delayed acknowledgement algorithm specified in 5580 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5581 * acknowledgement SHOULD be generated for at least every second packet 5582 * (not every second DATA chunk) received, and SHOULD be generated 5583 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5584 * some situations it may be beneficial for an SCTP transmitter to be 5585 * more conservative than the algorithms detailed in this document 5586 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5587 * the following algorithms allow. 5588 */ 5589 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5590 const struct sctp_endpoint *ep, 5591 const struct sctp_association *asoc, 5592 const sctp_subtype_t type, 5593 void *arg, 5594 sctp_cmd_seq_t *commands) 5595 { 5596 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5597 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5598 return SCTP_DISPOSITION_CONSUME; 5599 } 5600 5601 /* 5602 * sctp_sf_t1_init_timer_expire 5603 * 5604 * Section: 4 Note: 2 5605 * Verification Tag: 5606 * Inputs 5607 * (endpoint, asoc) 5608 * 5609 * RFC 2960 Section 4 Notes 5610 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5611 * and re-start the T1-init timer without changing state. This MUST 5612 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5613 * endpoint MUST abort the initialization process and report the 5614 * error to SCTP user. 5615 * 5616 * Outputs 5617 * (timers, events) 5618 * 5619 */ 5620 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5621 const struct sctp_endpoint *ep, 5622 const struct sctp_association *asoc, 5623 const sctp_subtype_t type, 5624 void *arg, 5625 sctp_cmd_seq_t *commands) 5626 { 5627 struct sctp_chunk *repl = NULL; 5628 struct sctp_bind_addr *bp; 5629 int attempts = asoc->init_err_counter + 1; 5630 5631 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5632 5633 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5634 5635 if (attempts <= asoc->max_init_attempts) { 5636 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5637 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5638 if (!repl) 5639 return SCTP_DISPOSITION_NOMEM; 5640 5641 /* Choose transport for INIT. */ 5642 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5643 SCTP_CHUNK(repl)); 5644 5645 /* Issue a sideeffect to do the needed accounting. */ 5646 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5647 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5648 5649 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5650 } else { 5651 pr_debug("%s: giving up on INIT, attempts:%d " 5652 "max_init_attempts:%d\n", __func__, attempts, 5653 asoc->max_init_attempts); 5654 5655 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5656 SCTP_ERROR(ETIMEDOUT)); 5657 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5658 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5659 return SCTP_DISPOSITION_DELETE_TCB; 5660 } 5661 5662 return SCTP_DISPOSITION_CONSUME; 5663 } 5664 5665 /* 5666 * sctp_sf_t1_cookie_timer_expire 5667 * 5668 * Section: 4 Note: 2 5669 * Verification Tag: 5670 * Inputs 5671 * (endpoint, asoc) 5672 * 5673 * RFC 2960 Section 4 Notes 5674 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5675 * COOKIE ECHO and re-start the T1-cookie timer without changing 5676 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5677 * After that, the endpoint MUST abort the initialization process and 5678 * report the error to SCTP user. 5679 * 5680 * Outputs 5681 * (timers, events) 5682 * 5683 */ 5684 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5685 const struct sctp_endpoint *ep, 5686 const struct sctp_association *asoc, 5687 const sctp_subtype_t type, 5688 void *arg, 5689 sctp_cmd_seq_t *commands) 5690 { 5691 struct sctp_chunk *repl = NULL; 5692 int attempts = asoc->init_err_counter + 1; 5693 5694 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5695 5696 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5697 5698 if (attempts <= asoc->max_init_attempts) { 5699 repl = sctp_make_cookie_echo(asoc, NULL); 5700 if (!repl) 5701 return SCTP_DISPOSITION_NOMEM; 5702 5703 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5704 SCTP_CHUNK(repl)); 5705 /* Issue a sideeffect to do the needed accounting. */ 5706 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5707 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5708 5709 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5710 } else { 5711 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5712 SCTP_ERROR(ETIMEDOUT)); 5713 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5714 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5715 return SCTP_DISPOSITION_DELETE_TCB; 5716 } 5717 5718 return SCTP_DISPOSITION_CONSUME; 5719 } 5720 5721 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5722 * with the updated last sequential TSN received from its peer. 5723 * 5724 * An endpoint should limit the number of retransmissions of the 5725 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5726 * If this threshold is exceeded the endpoint should destroy the TCB and 5727 * MUST report the peer endpoint unreachable to the upper layer (and 5728 * thus the association enters the CLOSED state). The reception of any 5729 * packet from its peer (i.e. as the peer sends all of its queued DATA 5730 * chunks) should clear the endpoint's retransmission count and restart 5731 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5732 * all of its queued DATA chunks that have not yet been sent. 5733 */ 5734 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5735 const struct sctp_endpoint *ep, 5736 const struct sctp_association *asoc, 5737 const sctp_subtype_t type, 5738 void *arg, 5739 sctp_cmd_seq_t *commands) 5740 { 5741 struct sctp_chunk *reply = NULL; 5742 5743 pr_debug("%s: timer T2 expired\n", __func__); 5744 5745 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5746 5747 ((struct sctp_association *)asoc)->shutdown_retries++; 5748 5749 if (asoc->overall_error_count >= asoc->max_retrans) { 5750 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5751 SCTP_ERROR(ETIMEDOUT)); 5752 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5753 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5754 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5755 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5756 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5757 return SCTP_DISPOSITION_DELETE_TCB; 5758 } 5759 5760 switch (asoc->state) { 5761 case SCTP_STATE_SHUTDOWN_SENT: 5762 reply = sctp_make_shutdown(asoc, NULL); 5763 break; 5764 5765 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5766 reply = sctp_make_shutdown_ack(asoc, NULL); 5767 break; 5768 5769 default: 5770 BUG(); 5771 break; 5772 } 5773 5774 if (!reply) 5775 goto nomem; 5776 5777 /* Do some failure management (Section 8.2). 5778 * If we remove the transport an SHUTDOWN was last sent to, don't 5779 * do failure management. 5780 */ 5781 if (asoc->shutdown_last_sent_to) 5782 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5783 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5784 5785 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5786 * the T2-shutdown timer. 5787 */ 5788 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5789 5790 /* Restart the T2-shutdown timer. */ 5791 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5792 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5793 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5794 return SCTP_DISPOSITION_CONSUME; 5795 5796 nomem: 5797 return SCTP_DISPOSITION_NOMEM; 5798 } 5799 5800 /* 5801 * ADDIP Section 4.1 ASCONF CHunk Procedures 5802 * If the T4 RTO timer expires the endpoint should do B1 to B5 5803 */ 5804 sctp_disposition_t sctp_sf_t4_timer_expire( 5805 struct net *net, 5806 const struct sctp_endpoint *ep, 5807 const struct sctp_association *asoc, 5808 const sctp_subtype_t type, 5809 void *arg, 5810 sctp_cmd_seq_t *commands) 5811 { 5812 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5813 struct sctp_transport *transport = chunk->transport; 5814 5815 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5816 5817 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5818 * detection on the appropriate destination address as defined in 5819 * RFC2960 [5] section 8.1 and 8.2. 5820 */ 5821 if (transport) 5822 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5823 SCTP_TRANSPORT(transport)); 5824 5825 /* Reconfig T4 timer and transport. */ 5826 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5827 5828 /* ADDIP 4.1 B2) Increment the association error counters and perform 5829 * endpoint failure detection on the association as defined in 5830 * RFC2960 [5] section 8.1 and 8.2. 5831 * association error counter is incremented in SCTP_CMD_STRIKE. 5832 */ 5833 if (asoc->overall_error_count >= asoc->max_retrans) { 5834 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5835 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5836 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5837 SCTP_ERROR(ETIMEDOUT)); 5838 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5839 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5840 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5841 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5842 return SCTP_DISPOSITION_ABORT; 5843 } 5844 5845 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5846 * the ASCONF chunk was sent by doubling the RTO timer value. 5847 * This is done in SCTP_CMD_STRIKE. 5848 */ 5849 5850 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5851 * choose an alternate destination address (please refer to RFC2960 5852 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5853 * chunk, it MUST be the same (including its serial number) as the last 5854 * ASCONF sent. 5855 */ 5856 sctp_chunk_hold(asoc->addip_last_asconf); 5857 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5858 SCTP_CHUNK(asoc->addip_last_asconf)); 5859 5860 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5861 * destination is selected, then the RTO used will be that of the new 5862 * destination address. 5863 */ 5864 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5865 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5866 5867 return SCTP_DISPOSITION_CONSUME; 5868 } 5869 5870 /* sctpimpguide-05 Section 2.12.2 5871 * The sender of the SHUTDOWN MAY also start an overall guard timer 5872 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5873 * At the expiration of this timer the sender SHOULD abort the association 5874 * by sending an ABORT chunk. 5875 */ 5876 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5877 const struct sctp_endpoint *ep, 5878 const struct sctp_association *asoc, 5879 const sctp_subtype_t type, 5880 void *arg, 5881 sctp_cmd_seq_t *commands) 5882 { 5883 struct sctp_chunk *reply = NULL; 5884 5885 pr_debug("%s: timer T5 expired\n", __func__); 5886 5887 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5888 5889 reply = sctp_make_abort(asoc, NULL, 0); 5890 if (!reply) 5891 goto nomem; 5892 5893 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5894 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5895 SCTP_ERROR(ETIMEDOUT)); 5896 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5897 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5898 5899 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5900 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5901 5902 return SCTP_DISPOSITION_DELETE_TCB; 5903 nomem: 5904 return SCTP_DISPOSITION_NOMEM; 5905 } 5906 5907 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5908 * the association is automatically closed by starting the shutdown process. 5909 * The work that needs to be done is same as when SHUTDOWN is initiated by 5910 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5911 */ 5912 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5913 struct net *net, 5914 const struct sctp_endpoint *ep, 5915 const struct sctp_association *asoc, 5916 const sctp_subtype_t type, 5917 void *arg, 5918 sctp_cmd_seq_t *commands) 5919 { 5920 int disposition; 5921 5922 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5923 5924 /* From 9.2 Shutdown of an Association 5925 * Upon receipt of the SHUTDOWN primitive from its upper 5926 * layer, the endpoint enters SHUTDOWN-PENDING state and 5927 * remains there until all outstanding data has been 5928 * acknowledged by its peer. The endpoint accepts no new data 5929 * from its upper layer, but retransmits data to the far end 5930 * if necessary to fill gaps. 5931 */ 5932 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5933 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5934 5935 disposition = SCTP_DISPOSITION_CONSUME; 5936 if (sctp_outq_is_empty(&asoc->outqueue)) { 5937 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5938 arg, commands); 5939 } 5940 return disposition; 5941 } 5942 5943 /***************************************************************************** 5944 * These are sa state functions which could apply to all types of events. 5945 ****************************************************************************/ 5946 5947 /* 5948 * This table entry is not implemented. 5949 * 5950 * Inputs 5951 * (endpoint, asoc, chunk) 5952 * 5953 * The return value is the disposition of the chunk. 5954 */ 5955 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5956 const struct sctp_endpoint *ep, 5957 const struct sctp_association *asoc, 5958 const sctp_subtype_t type, 5959 void *arg, 5960 sctp_cmd_seq_t *commands) 5961 { 5962 return SCTP_DISPOSITION_NOT_IMPL; 5963 } 5964 5965 /* 5966 * This table entry represents a bug. 5967 * 5968 * Inputs 5969 * (endpoint, asoc, chunk) 5970 * 5971 * The return value is the disposition of the chunk. 5972 */ 5973 sctp_disposition_t sctp_sf_bug(struct net *net, 5974 const struct sctp_endpoint *ep, 5975 const struct sctp_association *asoc, 5976 const sctp_subtype_t type, 5977 void *arg, 5978 sctp_cmd_seq_t *commands) 5979 { 5980 return SCTP_DISPOSITION_BUG; 5981 } 5982 5983 /* 5984 * This table entry represents the firing of a timer in the wrong state. 5985 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5986 * when the association is in the wrong state. This event should 5987 * be ignored, so as to prevent any rearming of the timer. 5988 * 5989 * Inputs 5990 * (endpoint, asoc, chunk) 5991 * 5992 * The return value is the disposition of the chunk. 5993 */ 5994 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5995 const struct sctp_endpoint *ep, 5996 const struct sctp_association *asoc, 5997 const sctp_subtype_t type, 5998 void *arg, 5999 sctp_cmd_seq_t *commands) 6000 { 6001 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6002 6003 return SCTP_DISPOSITION_CONSUME; 6004 } 6005 6006 /******************************************************************** 6007 * 2nd Level Abstractions 6008 ********************************************************************/ 6009 6010 /* Pull the SACK chunk based on the SACK header. */ 6011 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6012 { 6013 struct sctp_sackhdr *sack; 6014 unsigned int len; 6015 __u16 num_blocks; 6016 __u16 num_dup_tsns; 6017 6018 /* Protect ourselves from reading too far into 6019 * the skb from a bogus sender. 6020 */ 6021 sack = (struct sctp_sackhdr *) chunk->skb->data; 6022 6023 num_blocks = ntohs(sack->num_gap_ack_blocks); 6024 num_dup_tsns = ntohs(sack->num_dup_tsns); 6025 len = sizeof(struct sctp_sackhdr); 6026 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6027 if (len > chunk->skb->len) 6028 return NULL; 6029 6030 skb_pull(chunk->skb, len); 6031 6032 return sack; 6033 } 6034 6035 /* Create an ABORT packet to be sent as a response, with the specified 6036 * error causes. 6037 */ 6038 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 6039 const struct sctp_endpoint *ep, 6040 const struct sctp_association *asoc, 6041 struct sctp_chunk *chunk, 6042 const void *payload, 6043 size_t paylen) 6044 { 6045 struct sctp_packet *packet; 6046 struct sctp_chunk *abort; 6047 6048 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6049 6050 if (packet) { 6051 /* Make an ABORT. 6052 * The T bit will be set if the asoc is NULL. 6053 */ 6054 abort = sctp_make_abort(asoc, chunk, paylen); 6055 if (!abort) { 6056 sctp_ootb_pkt_free(packet); 6057 return NULL; 6058 } 6059 6060 /* Reflect vtag if T-Bit is set */ 6061 if (sctp_test_T_bit(abort)) 6062 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6063 6064 /* Add specified error causes, i.e., payload, to the 6065 * end of the chunk. 6066 */ 6067 sctp_addto_chunk(abort, paylen, payload); 6068 6069 /* Set the skb to the belonging sock for accounting. */ 6070 abort->skb->sk = ep->base.sk; 6071 6072 sctp_packet_append_chunk(packet, abort); 6073 6074 } 6075 6076 return packet; 6077 } 6078 6079 /* Allocate a packet for responding in the OOTB conditions. */ 6080 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 6081 const struct sctp_association *asoc, 6082 const struct sctp_chunk *chunk) 6083 { 6084 struct sctp_packet *packet; 6085 struct sctp_transport *transport; 6086 __u16 sport; 6087 __u16 dport; 6088 __u32 vtag; 6089 6090 /* Get the source and destination port from the inbound packet. */ 6091 sport = ntohs(chunk->sctp_hdr->dest); 6092 dport = ntohs(chunk->sctp_hdr->source); 6093 6094 /* The V-tag is going to be the same as the inbound packet if no 6095 * association exists, otherwise, use the peer's vtag. 6096 */ 6097 if (asoc) { 6098 /* Special case the INIT-ACK as there is no peer's vtag 6099 * yet. 6100 */ 6101 switch (chunk->chunk_hdr->type) { 6102 case SCTP_CID_INIT_ACK: 6103 { 6104 sctp_initack_chunk_t *initack; 6105 6106 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6107 vtag = ntohl(initack->init_hdr.init_tag); 6108 break; 6109 } 6110 default: 6111 vtag = asoc->peer.i.init_tag; 6112 break; 6113 } 6114 } else { 6115 /* Special case the INIT and stale COOKIE_ECHO as there is no 6116 * vtag yet. 6117 */ 6118 switch (chunk->chunk_hdr->type) { 6119 case SCTP_CID_INIT: 6120 { 6121 sctp_init_chunk_t *init; 6122 6123 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6124 vtag = ntohl(init->init_hdr.init_tag); 6125 break; 6126 } 6127 default: 6128 vtag = ntohl(chunk->sctp_hdr->vtag); 6129 break; 6130 } 6131 } 6132 6133 /* Make a transport for the bucket, Eliza... */ 6134 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6135 if (!transport) 6136 goto nomem; 6137 6138 /* Cache a route for the transport with the chunk's destination as 6139 * the source address. 6140 */ 6141 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6142 sctp_sk(net->sctp.ctl_sock)); 6143 6144 packet = &transport->packet; 6145 sctp_packet_init(packet, transport, sport, dport); 6146 sctp_packet_config(packet, vtag, 0); 6147 6148 return packet; 6149 6150 nomem: 6151 return NULL; 6152 } 6153 6154 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6155 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6156 { 6157 sctp_transport_free(packet->transport); 6158 } 6159 6160 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6161 static void sctp_send_stale_cookie_err(struct net *net, 6162 const struct sctp_endpoint *ep, 6163 const struct sctp_association *asoc, 6164 const struct sctp_chunk *chunk, 6165 sctp_cmd_seq_t *commands, 6166 struct sctp_chunk *err_chunk) 6167 { 6168 struct sctp_packet *packet; 6169 6170 if (err_chunk) { 6171 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6172 if (packet) { 6173 struct sctp_signed_cookie *cookie; 6174 6175 /* Override the OOTB vtag from the cookie. */ 6176 cookie = chunk->subh.cookie_hdr; 6177 packet->vtag = cookie->c.peer_vtag; 6178 6179 /* Set the skb to the belonging sock for accounting. */ 6180 err_chunk->skb->sk = ep->base.sk; 6181 sctp_packet_append_chunk(packet, err_chunk); 6182 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6183 SCTP_PACKET(packet)); 6184 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6185 } else 6186 sctp_chunk_free (err_chunk); 6187 } 6188 } 6189 6190 6191 /* Process a data chunk */ 6192 static int sctp_eat_data(const struct sctp_association *asoc, 6193 struct sctp_chunk *chunk, 6194 sctp_cmd_seq_t *commands) 6195 { 6196 sctp_datahdr_t *data_hdr; 6197 struct sctp_chunk *err; 6198 size_t datalen; 6199 sctp_verb_t deliver; 6200 int tmp; 6201 __u32 tsn; 6202 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6203 struct sock *sk = asoc->base.sk; 6204 struct net *net = sock_net(sk); 6205 u16 ssn; 6206 u16 sid; 6207 u8 ordered = 0; 6208 6209 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6210 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6211 6212 tsn = ntohl(data_hdr->tsn); 6213 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6214 6215 /* ASSERT: Now skb->data is really the user data. */ 6216 6217 /* Process ECN based congestion. 6218 * 6219 * Since the chunk structure is reused for all chunks within 6220 * a packet, we use ecn_ce_done to track if we've already 6221 * done CE processing for this packet. 6222 * 6223 * We need to do ECN processing even if we plan to discard the 6224 * chunk later. 6225 */ 6226 6227 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6228 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6229 chunk->ecn_ce_done = 1; 6230 6231 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6232 /* Do real work as sideffect. */ 6233 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6234 SCTP_U32(tsn)); 6235 } 6236 } 6237 6238 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6239 if (tmp < 0) { 6240 /* The TSN is too high--silently discard the chunk and 6241 * count on it getting retransmitted later. 6242 */ 6243 if (chunk->asoc) 6244 chunk->asoc->stats.outofseqtsns++; 6245 return SCTP_IERROR_HIGH_TSN; 6246 } else if (tmp > 0) { 6247 /* This is a duplicate. Record it. */ 6248 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6249 return SCTP_IERROR_DUP_TSN; 6250 } 6251 6252 /* This is a new TSN. */ 6253 6254 /* Discard if there is no room in the receive window. 6255 * Actually, allow a little bit of overflow (up to a MTU). 6256 */ 6257 datalen = ntohs(chunk->chunk_hdr->length); 6258 datalen -= sizeof(sctp_data_chunk_t); 6259 6260 deliver = SCTP_CMD_CHUNK_ULP; 6261 6262 /* Think about partial delivery. */ 6263 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6264 6265 /* Even if we don't accept this chunk there is 6266 * memory pressure. 6267 */ 6268 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6269 } 6270 6271 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6272 * seems a bit troublesome in that frag_point varies based on 6273 * PMTU. In cases, such as loopback, this might be a rather 6274 * large spill over. 6275 */ 6276 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6277 (datalen > asoc->rwnd + asoc->frag_point))) { 6278 6279 /* If this is the next TSN, consider reneging to make 6280 * room. Note: Playing nice with a confused sender. A 6281 * malicious sender can still eat up all our buffer 6282 * space and in the future we may want to detect and 6283 * do more drastic reneging. 6284 */ 6285 if (sctp_tsnmap_has_gap(map) && 6286 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6287 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6288 deliver = SCTP_CMD_RENEGE; 6289 } else { 6290 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6291 __func__, tsn, datalen, asoc->rwnd); 6292 6293 return SCTP_IERROR_IGNORE_TSN; 6294 } 6295 } 6296 6297 /* 6298 * Also try to renege to limit our memory usage in the event that 6299 * we are under memory pressure 6300 * If we can't renege, don't worry about it, the sk_rmem_schedule 6301 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6302 * memory usage too much 6303 */ 6304 if (*sk->sk_prot_creator->memory_pressure) { 6305 if (sctp_tsnmap_has_gap(map) && 6306 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6307 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6308 __func__, tsn); 6309 deliver = SCTP_CMD_RENEGE; 6310 } 6311 } 6312 6313 /* 6314 * Section 3.3.10.9 No User Data (9) 6315 * 6316 * Cause of error 6317 * --------------- 6318 * No User Data: This error cause is returned to the originator of a 6319 * DATA chunk if a received DATA chunk has no user data. 6320 */ 6321 if (unlikely(0 == datalen)) { 6322 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6323 if (err) { 6324 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6325 SCTP_CHUNK(err)); 6326 } 6327 /* We are going to ABORT, so we might as well stop 6328 * processing the rest of the chunks in the packet. 6329 */ 6330 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6331 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6332 SCTP_ERROR(ECONNABORTED)); 6333 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6334 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6335 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6336 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6337 return SCTP_IERROR_NO_DATA; 6338 } 6339 6340 chunk->data_accepted = 1; 6341 6342 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6343 * if we renege and the chunk arrives again. 6344 */ 6345 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6346 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6347 if (chunk->asoc) 6348 chunk->asoc->stats.iuodchunks++; 6349 } else { 6350 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6351 if (chunk->asoc) 6352 chunk->asoc->stats.iodchunks++; 6353 ordered = 1; 6354 } 6355 6356 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6357 * 6358 * If an endpoint receive a DATA chunk with an invalid stream 6359 * identifier, it shall acknowledge the reception of the DATA chunk 6360 * following the normal procedure, immediately send an ERROR chunk 6361 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6362 * and discard the DATA chunk. 6363 */ 6364 sid = ntohs(data_hdr->stream); 6365 if (sid >= asoc->stream->incnt) { 6366 /* Mark tsn as received even though we drop it */ 6367 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6368 6369 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6370 &data_hdr->stream, 6371 sizeof(data_hdr->stream), 6372 sizeof(u16)); 6373 if (err) 6374 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6375 SCTP_CHUNK(err)); 6376 return SCTP_IERROR_BAD_STREAM; 6377 } 6378 6379 /* Check to see if the SSN is possible for this TSN. 6380 * The biggest gap we can record is 4K wide. Since SSNs wrap 6381 * at an unsigned short, there is no way that an SSN can 6382 * wrap and for a valid TSN. We can simply check if the current 6383 * SSN is smaller then the next expected one. If it is, it wrapped 6384 * and is invalid. 6385 */ 6386 ssn = ntohs(data_hdr->ssn); 6387 if (ordered && SSN_lt(ssn, sctp_ssn_peek(asoc->stream, in, sid))) 6388 return SCTP_IERROR_PROTO_VIOLATION; 6389 6390 /* Send the data up to the user. Note: Schedule the 6391 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6392 * chunk needs the updated rwnd. 6393 */ 6394 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6395 6396 return SCTP_IERROR_NO_ERROR; 6397 } 6398