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 /* Set temp so that it won't be added into hashtable */ 2092 new_asoc->temp = 1; 2093 2094 /* Compare the tie_tag in cookie with the verification tag of 2095 * current association. 2096 */ 2097 action = sctp_tietags_compare(new_asoc, asoc); 2098 2099 switch (action) { 2100 case 'A': /* Association restart. */ 2101 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2102 new_asoc); 2103 break; 2104 2105 case 'B': /* Collision case B. */ 2106 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2107 new_asoc); 2108 break; 2109 2110 case 'C': /* Collision case C. */ 2111 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2112 new_asoc); 2113 break; 2114 2115 case 'D': /* Collision case D. */ 2116 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2117 new_asoc); 2118 break; 2119 2120 default: /* Discard packet for all others. */ 2121 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2122 break; 2123 } 2124 2125 /* Delete the tempory new association. */ 2126 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2127 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2128 2129 /* Restore association pointer to provide SCTP command interpeter 2130 * with a valid context in case it needs to manipulate 2131 * the queues */ 2132 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2133 SCTP_ASOC((struct sctp_association *)asoc)); 2134 2135 return retval; 2136 2137 nomem: 2138 return SCTP_DISPOSITION_NOMEM; 2139 } 2140 2141 /* 2142 * Process an ABORT. (SHUTDOWN-PENDING state) 2143 * 2144 * See sctp_sf_do_9_1_abort(). 2145 */ 2146 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2147 struct net *net, 2148 const struct sctp_endpoint *ep, 2149 const struct sctp_association *asoc, 2150 const sctp_subtype_t type, 2151 void *arg, 2152 sctp_cmd_seq_t *commands) 2153 { 2154 struct sctp_chunk *chunk = arg; 2155 2156 if (!sctp_vtag_verify_either(chunk, asoc)) 2157 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2158 2159 /* Make sure that the ABORT chunk has a valid length. 2160 * Since this is an ABORT chunk, we have to discard it 2161 * because of the following text: 2162 * RFC 2960, Section 3.3.7 2163 * If an endpoint receives an ABORT with a format error or for an 2164 * association that doesn't exist, it MUST silently discard it. 2165 * Because the length is "invalid", we can't really discard just 2166 * as we do not know its true length. So, to be safe, discard the 2167 * packet. 2168 */ 2169 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2170 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2171 2172 /* ADD-IP: Special case for ABORT chunks 2173 * F4) One special consideration is that ABORT Chunks arriving 2174 * destined to the IP address being deleted MUST be 2175 * ignored (see Section 5.3.1 for further details). 2176 */ 2177 if (SCTP_ADDR_DEL == 2178 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2179 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2180 2181 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2182 } 2183 2184 /* 2185 * Process an ABORT. (SHUTDOWN-SENT state) 2186 * 2187 * See sctp_sf_do_9_1_abort(). 2188 */ 2189 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2190 const struct sctp_endpoint *ep, 2191 const struct sctp_association *asoc, 2192 const sctp_subtype_t type, 2193 void *arg, 2194 sctp_cmd_seq_t *commands) 2195 { 2196 struct sctp_chunk *chunk = arg; 2197 2198 if (!sctp_vtag_verify_either(chunk, asoc)) 2199 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2200 2201 /* Make sure that the ABORT chunk has a valid length. 2202 * Since this is an ABORT chunk, we have to discard it 2203 * because of the following text: 2204 * RFC 2960, Section 3.3.7 2205 * If an endpoint receives an ABORT with a format error or for an 2206 * association that doesn't exist, it MUST silently discard it. 2207 * Because the length is "invalid", we can't really discard just 2208 * as we do not know its true length. So, to be safe, discard the 2209 * packet. 2210 */ 2211 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2212 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2213 2214 /* ADD-IP: Special case for ABORT chunks 2215 * F4) One special consideration is that ABORT Chunks arriving 2216 * destined to the IP address being deleted MUST be 2217 * ignored (see Section 5.3.1 for further details). 2218 */ 2219 if (SCTP_ADDR_DEL == 2220 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2221 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2222 2223 /* Stop the T2-shutdown timer. */ 2224 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2225 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2226 2227 /* Stop the T5-shutdown guard timer. */ 2228 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2229 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2230 2231 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2232 } 2233 2234 /* 2235 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2236 * 2237 * See sctp_sf_do_9_1_abort(). 2238 */ 2239 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2240 struct net *net, 2241 const struct sctp_endpoint *ep, 2242 const struct sctp_association *asoc, 2243 const sctp_subtype_t type, 2244 void *arg, 2245 sctp_cmd_seq_t *commands) 2246 { 2247 /* The same T2 timer, so we should be able to use 2248 * common function with the SHUTDOWN-SENT state. 2249 */ 2250 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2251 } 2252 2253 /* 2254 * Handle an Error received in COOKIE_ECHOED state. 2255 * 2256 * Only handle the error type of stale COOKIE Error, the other errors will 2257 * be ignored. 2258 * 2259 * Inputs 2260 * (endpoint, asoc, chunk) 2261 * 2262 * Outputs 2263 * (asoc, reply_msg, msg_up, timers, counters) 2264 * 2265 * The return value is the disposition of the chunk. 2266 */ 2267 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2268 const struct sctp_endpoint *ep, 2269 const struct sctp_association *asoc, 2270 const sctp_subtype_t type, 2271 void *arg, 2272 sctp_cmd_seq_t *commands) 2273 { 2274 struct sctp_chunk *chunk = arg; 2275 sctp_errhdr_t *err; 2276 2277 if (!sctp_vtag_verify(chunk, asoc)) 2278 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2279 2280 /* Make sure that the ERROR chunk has a valid length. 2281 * The parameter walking depends on this as well. 2282 */ 2283 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2284 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2285 commands); 2286 2287 /* Process the error here */ 2288 /* FUTURE FIXME: When PR-SCTP related and other optional 2289 * parms are emitted, this will have to change to handle multiple 2290 * errors. 2291 */ 2292 sctp_walk_errors(err, chunk->chunk_hdr) { 2293 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2294 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2295 arg, commands); 2296 } 2297 2298 /* It is possible to have malformed error causes, and that 2299 * will cause us to end the walk early. However, since 2300 * we are discarding the packet, there should be no adverse 2301 * affects. 2302 */ 2303 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2304 } 2305 2306 /* 2307 * Handle a Stale COOKIE Error 2308 * 2309 * Section: 5.2.6 Handle Stale COOKIE Error 2310 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2311 * one of the following three alternatives. 2312 * ... 2313 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2314 * Preservative parameter requesting an extension to the lifetime of 2315 * the State Cookie. When calculating the time extension, an 2316 * implementation SHOULD use the RTT information measured based on the 2317 * previous COOKIE ECHO / ERROR exchange, and should add no more 2318 * than 1 second beyond the measured RTT, due to long State Cookie 2319 * lifetimes making the endpoint more subject to a replay attack. 2320 * 2321 * Verification Tag: Not explicit, but safe to ignore. 2322 * 2323 * Inputs 2324 * (endpoint, asoc, chunk) 2325 * 2326 * Outputs 2327 * (asoc, reply_msg, msg_up, timers, counters) 2328 * 2329 * The return value is the disposition of the chunk. 2330 */ 2331 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2332 const struct sctp_endpoint *ep, 2333 const struct sctp_association *asoc, 2334 const sctp_subtype_t type, 2335 void *arg, 2336 sctp_cmd_seq_t *commands) 2337 { 2338 struct sctp_chunk *chunk = arg; 2339 u32 stale; 2340 sctp_cookie_preserve_param_t bht; 2341 sctp_errhdr_t *err; 2342 struct sctp_chunk *reply; 2343 struct sctp_bind_addr *bp; 2344 int attempts = asoc->init_err_counter + 1; 2345 2346 if (attempts > asoc->max_init_attempts) { 2347 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2348 SCTP_ERROR(ETIMEDOUT)); 2349 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2350 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2351 return SCTP_DISPOSITION_DELETE_TCB; 2352 } 2353 2354 err = (sctp_errhdr_t *)(chunk->skb->data); 2355 2356 /* When calculating the time extension, an implementation 2357 * SHOULD use the RTT information measured based on the 2358 * previous COOKIE ECHO / ERROR exchange, and should add no 2359 * more than 1 second beyond the measured RTT, due to long 2360 * State Cookie lifetimes making the endpoint more subject to 2361 * a replay attack. 2362 * Measure of Staleness's unit is usec. (1/1000000 sec) 2363 * Suggested Cookie Life-span Increment's unit is msec. 2364 * (1/1000 sec) 2365 * In general, if you use the suggested cookie life, the value 2366 * found in the field of measure of staleness should be doubled 2367 * to give ample time to retransmit the new cookie and thus 2368 * yield a higher probability of success on the reattempt. 2369 */ 2370 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2371 stale = (stale * 2) / 1000; 2372 2373 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2374 bht.param_hdr.length = htons(sizeof(bht)); 2375 bht.lifespan_increment = htonl(stale); 2376 2377 /* Build that new INIT chunk. */ 2378 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2379 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2380 if (!reply) 2381 goto nomem; 2382 2383 sctp_addto_chunk(reply, sizeof(bht), &bht); 2384 2385 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2386 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2387 2388 /* Stop pending T3-rtx and heartbeat timers */ 2389 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2390 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2391 2392 /* Delete non-primary peer ip addresses since we are transitioning 2393 * back to the COOKIE-WAIT state 2394 */ 2395 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2396 2397 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2398 * resend 2399 */ 2400 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2401 SCTP_TRANSPORT(asoc->peer.primary_path)); 2402 2403 /* Cast away the const modifier, as we want to just 2404 * rerun it through as a sideffect. 2405 */ 2406 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2407 2408 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2409 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2410 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2411 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2412 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2413 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2414 2415 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2416 2417 return SCTP_DISPOSITION_CONSUME; 2418 2419 nomem: 2420 return SCTP_DISPOSITION_NOMEM; 2421 } 2422 2423 /* 2424 * Process an ABORT. 2425 * 2426 * Section: 9.1 2427 * After checking the Verification Tag, the receiving endpoint shall 2428 * remove the association from its record, and shall report the 2429 * termination to its upper layer. 2430 * 2431 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2432 * B) Rules for packet carrying ABORT: 2433 * 2434 * - The endpoint shall always fill in the Verification Tag field of the 2435 * outbound packet with the destination endpoint's tag value if it 2436 * is known. 2437 * 2438 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2439 * MUST follow the procedure described in Section 8.4. 2440 * 2441 * - The receiver MUST accept the packet if the Verification Tag 2442 * matches either its own tag, OR the tag of its peer. Otherwise, the 2443 * receiver MUST silently discard the packet and take no further 2444 * action. 2445 * 2446 * Inputs 2447 * (endpoint, asoc, chunk) 2448 * 2449 * Outputs 2450 * (asoc, reply_msg, msg_up, timers, counters) 2451 * 2452 * The return value is the disposition of the chunk. 2453 */ 2454 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2455 const struct sctp_endpoint *ep, 2456 const struct sctp_association *asoc, 2457 const sctp_subtype_t type, 2458 void *arg, 2459 sctp_cmd_seq_t *commands) 2460 { 2461 struct sctp_chunk *chunk = arg; 2462 2463 if (!sctp_vtag_verify_either(chunk, asoc)) 2464 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2465 2466 /* Make sure that the ABORT chunk has a valid length. 2467 * Since this is an ABORT chunk, we have to discard it 2468 * because of the following text: 2469 * RFC 2960, Section 3.3.7 2470 * If an endpoint receives an ABORT with a format error or for an 2471 * association that doesn't exist, it MUST silently discard it. 2472 * Because the length is "invalid", we can't really discard just 2473 * as we do not know its true length. So, to be safe, discard the 2474 * packet. 2475 */ 2476 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2477 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2478 2479 /* ADD-IP: Special case for ABORT chunks 2480 * F4) One special consideration is that ABORT Chunks arriving 2481 * destined to the IP address being deleted MUST be 2482 * ignored (see Section 5.3.1 for further details). 2483 */ 2484 if (SCTP_ADDR_DEL == 2485 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2486 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2487 2488 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2489 } 2490 2491 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2492 const struct sctp_endpoint *ep, 2493 const struct sctp_association *asoc, 2494 const sctp_subtype_t type, 2495 void *arg, 2496 sctp_cmd_seq_t *commands) 2497 { 2498 struct sctp_chunk *chunk = arg; 2499 unsigned int len; 2500 __be16 error = SCTP_ERROR_NO_ERROR; 2501 2502 /* See if we have an error cause code in the chunk. */ 2503 len = ntohs(chunk->chunk_hdr->length); 2504 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2505 2506 sctp_errhdr_t *err; 2507 sctp_walk_errors(err, chunk->chunk_hdr); 2508 if ((void *)err != (void *)chunk->chunk_end) 2509 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2510 2511 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2512 } 2513 2514 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2515 /* ASSOC_FAILED will DELETE_TCB. */ 2516 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2517 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2518 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2519 2520 return SCTP_DISPOSITION_ABORT; 2521 } 2522 2523 /* 2524 * Process an ABORT. (COOKIE-WAIT state) 2525 * 2526 * See sctp_sf_do_9_1_abort() above. 2527 */ 2528 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2529 const struct sctp_endpoint *ep, 2530 const struct sctp_association *asoc, 2531 const sctp_subtype_t type, 2532 void *arg, 2533 sctp_cmd_seq_t *commands) 2534 { 2535 struct sctp_chunk *chunk = arg; 2536 unsigned int len; 2537 __be16 error = SCTP_ERROR_NO_ERROR; 2538 2539 if (!sctp_vtag_verify_either(chunk, asoc)) 2540 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2541 2542 /* Make sure that the ABORT chunk has a valid length. 2543 * Since this is an ABORT chunk, we have to discard it 2544 * because of the following text: 2545 * RFC 2960, Section 3.3.7 2546 * If an endpoint receives an ABORT with a format error or for an 2547 * association that doesn't exist, it MUST silently discard it. 2548 * Because the length is "invalid", we can't really discard just 2549 * as we do not know its true length. So, to be safe, discard the 2550 * packet. 2551 */ 2552 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2553 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2554 2555 /* See if we have an error cause code in the chunk. */ 2556 len = ntohs(chunk->chunk_hdr->length); 2557 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2558 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2559 2560 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2561 chunk->transport); 2562 } 2563 2564 /* 2565 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2566 */ 2567 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2568 const struct sctp_endpoint *ep, 2569 const struct sctp_association *asoc, 2570 const sctp_subtype_t type, 2571 void *arg, 2572 sctp_cmd_seq_t *commands) 2573 { 2574 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2575 ENOPROTOOPT, asoc, 2576 (struct sctp_transport *)arg); 2577 } 2578 2579 /* 2580 * Process an ABORT. (COOKIE-ECHOED state) 2581 */ 2582 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2583 const struct sctp_endpoint *ep, 2584 const struct sctp_association *asoc, 2585 const sctp_subtype_t type, 2586 void *arg, 2587 sctp_cmd_seq_t *commands) 2588 { 2589 /* There is a single T1 timer, so we should be able to use 2590 * common function with the COOKIE-WAIT state. 2591 */ 2592 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2593 } 2594 2595 /* 2596 * Stop T1 timer and abort association with "INIT failed". 2597 * 2598 * This is common code called by several sctp_sf_*_abort() functions above. 2599 */ 2600 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2601 sctp_cmd_seq_t *commands, 2602 __be16 error, int sk_err, 2603 const struct sctp_association *asoc, 2604 struct sctp_transport *transport) 2605 { 2606 pr_debug("%s: ABORT received (INIT)\n", __func__); 2607 2608 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2609 SCTP_STATE(SCTP_STATE_CLOSED)); 2610 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2611 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2612 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2613 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2614 /* CMD_INIT_FAILED will DELETE_TCB. */ 2615 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2616 SCTP_PERR(error)); 2617 2618 return SCTP_DISPOSITION_ABORT; 2619 } 2620 2621 /* 2622 * sctp_sf_do_9_2_shut 2623 * 2624 * Section: 9.2 2625 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2626 * - enter the SHUTDOWN-RECEIVED state, 2627 * 2628 * - stop accepting new data from its SCTP user 2629 * 2630 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2631 * that all its outstanding DATA chunks have been received by the 2632 * SHUTDOWN sender. 2633 * 2634 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2635 * send a SHUTDOWN in response to a ULP request. And should discard 2636 * subsequent SHUTDOWN chunks. 2637 * 2638 * If there are still outstanding DATA chunks left, the SHUTDOWN 2639 * receiver shall continue to follow normal data transmission 2640 * procedures defined in Section 6 until all outstanding DATA chunks 2641 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2642 * new data from its SCTP user. 2643 * 2644 * Verification Tag: 8.5 Verification Tag [Normal verification] 2645 * 2646 * Inputs 2647 * (endpoint, asoc, chunk) 2648 * 2649 * Outputs 2650 * (asoc, reply_msg, msg_up, timers, counters) 2651 * 2652 * The return value is the disposition of the chunk. 2653 */ 2654 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2655 const struct sctp_endpoint *ep, 2656 const struct sctp_association *asoc, 2657 const sctp_subtype_t type, 2658 void *arg, 2659 sctp_cmd_seq_t *commands) 2660 { 2661 struct sctp_chunk *chunk = arg; 2662 sctp_shutdownhdr_t *sdh; 2663 sctp_disposition_t disposition; 2664 struct sctp_ulpevent *ev; 2665 __u32 ctsn; 2666 2667 if (!sctp_vtag_verify(chunk, asoc)) 2668 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2669 2670 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2671 if (!sctp_chunk_length_valid(chunk, 2672 sizeof(struct sctp_shutdown_chunk_t))) 2673 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2674 commands); 2675 2676 /* Convert the elaborate header. */ 2677 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2678 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2679 chunk->subh.shutdown_hdr = sdh; 2680 ctsn = ntohl(sdh->cum_tsn_ack); 2681 2682 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2683 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2684 asoc->ctsn_ack_point); 2685 2686 return SCTP_DISPOSITION_DISCARD; 2687 } 2688 2689 /* If Cumulative TSN Ack beyond the max tsn currently 2690 * send, terminating the association and respond to the 2691 * sender with an ABORT. 2692 */ 2693 if (!TSN_lt(ctsn, asoc->next_tsn)) 2694 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2695 2696 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2697 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2698 * inform the application that it should cease sending data. 2699 */ 2700 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2701 if (!ev) { 2702 disposition = SCTP_DISPOSITION_NOMEM; 2703 goto out; 2704 } 2705 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2706 2707 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2708 * - enter the SHUTDOWN-RECEIVED state, 2709 * - stop accepting new data from its SCTP user 2710 * 2711 * [This is implicit in the new state.] 2712 */ 2713 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2714 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2715 disposition = SCTP_DISPOSITION_CONSUME; 2716 2717 if (sctp_outq_is_empty(&asoc->outqueue)) { 2718 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2719 arg, commands); 2720 } 2721 2722 if (SCTP_DISPOSITION_NOMEM == disposition) 2723 goto out; 2724 2725 /* - verify, by checking the Cumulative TSN Ack field of the 2726 * chunk, that all its outstanding DATA chunks have been 2727 * received by the SHUTDOWN sender. 2728 */ 2729 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2730 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2731 2732 out: 2733 return disposition; 2734 } 2735 2736 /* 2737 * sctp_sf_do_9_2_shut_ctsn 2738 * 2739 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2740 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2741 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2742 * MUST be processed. 2743 */ 2744 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2745 const struct sctp_endpoint *ep, 2746 const struct sctp_association *asoc, 2747 const sctp_subtype_t type, 2748 void *arg, 2749 sctp_cmd_seq_t *commands) 2750 { 2751 struct sctp_chunk *chunk = arg; 2752 sctp_shutdownhdr_t *sdh; 2753 __u32 ctsn; 2754 2755 if (!sctp_vtag_verify(chunk, asoc)) 2756 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2757 2758 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2759 if (!sctp_chunk_length_valid(chunk, 2760 sizeof(struct sctp_shutdown_chunk_t))) 2761 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2762 commands); 2763 2764 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2765 ctsn = ntohl(sdh->cum_tsn_ack); 2766 2767 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2768 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2769 asoc->ctsn_ack_point); 2770 2771 return SCTP_DISPOSITION_DISCARD; 2772 } 2773 2774 /* If Cumulative TSN Ack beyond the max tsn currently 2775 * send, terminating the association and respond to the 2776 * sender with an ABORT. 2777 */ 2778 if (!TSN_lt(ctsn, asoc->next_tsn)) 2779 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2780 2781 /* verify, by checking the Cumulative TSN Ack field of the 2782 * chunk, that all its outstanding DATA chunks have been 2783 * received by the SHUTDOWN sender. 2784 */ 2785 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2786 SCTP_BE32(sdh->cum_tsn_ack)); 2787 2788 return SCTP_DISPOSITION_CONSUME; 2789 } 2790 2791 /* RFC 2960 9.2 2792 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2793 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2794 * transport addresses (either in the IP addresses or in the INIT chunk) 2795 * that belong to this association, it should discard the INIT chunk and 2796 * retransmit the SHUTDOWN ACK chunk. 2797 */ 2798 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2799 const struct sctp_endpoint *ep, 2800 const struct sctp_association *asoc, 2801 const sctp_subtype_t type, 2802 void *arg, 2803 sctp_cmd_seq_t *commands) 2804 { 2805 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2806 struct sctp_chunk *reply; 2807 2808 /* Make sure that the chunk has a valid length */ 2809 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2810 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2811 commands); 2812 2813 /* Since we are not going to really process this INIT, there 2814 * is no point in verifying chunk boundries. Just generate 2815 * the SHUTDOWN ACK. 2816 */ 2817 reply = sctp_make_shutdown_ack(asoc, chunk); 2818 if (NULL == reply) 2819 goto nomem; 2820 2821 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2822 * the T2-SHUTDOWN timer. 2823 */ 2824 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2825 2826 /* and restart the T2-shutdown timer. */ 2827 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2828 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2829 2830 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2831 2832 return SCTP_DISPOSITION_CONSUME; 2833 nomem: 2834 return SCTP_DISPOSITION_NOMEM; 2835 } 2836 2837 /* 2838 * sctp_sf_do_ecn_cwr 2839 * 2840 * Section: Appendix A: Explicit Congestion Notification 2841 * 2842 * CWR: 2843 * 2844 * RFC 2481 details a specific bit for a sender to send in the header of 2845 * its next outbound TCP segment to indicate to its peer that it has 2846 * reduced its congestion window. This is termed the CWR bit. For 2847 * SCTP the same indication is made by including the CWR chunk. 2848 * This chunk contains one data element, i.e. the TSN number that 2849 * was sent in the ECNE chunk. This element represents the lowest 2850 * TSN number in the datagram that was originally marked with the 2851 * CE bit. 2852 * 2853 * Verification Tag: 8.5 Verification Tag [Normal verification] 2854 * Inputs 2855 * (endpoint, asoc, chunk) 2856 * 2857 * Outputs 2858 * (asoc, reply_msg, msg_up, timers, counters) 2859 * 2860 * The return value is the disposition of the chunk. 2861 */ 2862 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2863 const struct sctp_endpoint *ep, 2864 const struct sctp_association *asoc, 2865 const sctp_subtype_t type, 2866 void *arg, 2867 sctp_cmd_seq_t *commands) 2868 { 2869 sctp_cwrhdr_t *cwr; 2870 struct sctp_chunk *chunk = arg; 2871 u32 lowest_tsn; 2872 2873 if (!sctp_vtag_verify(chunk, asoc)) 2874 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2875 2876 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2877 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2878 commands); 2879 2880 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2881 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2882 2883 lowest_tsn = ntohl(cwr->lowest_tsn); 2884 2885 /* Does this CWR ack the last sent congestion notification? */ 2886 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2887 /* Stop sending ECNE. */ 2888 sctp_add_cmd_sf(commands, 2889 SCTP_CMD_ECN_CWR, 2890 SCTP_U32(lowest_tsn)); 2891 } 2892 return SCTP_DISPOSITION_CONSUME; 2893 } 2894 2895 /* 2896 * sctp_sf_do_ecne 2897 * 2898 * Section: Appendix A: Explicit Congestion Notification 2899 * 2900 * ECN-Echo 2901 * 2902 * RFC 2481 details a specific bit for a receiver to send back in its 2903 * TCP acknowledgements to notify the sender of the Congestion 2904 * Experienced (CE) bit having arrived from the network. For SCTP this 2905 * same indication is made by including the ECNE chunk. This chunk 2906 * contains one data element, i.e. the lowest TSN associated with the IP 2907 * datagram marked with the CE bit..... 2908 * 2909 * Verification Tag: 8.5 Verification Tag [Normal verification] 2910 * Inputs 2911 * (endpoint, asoc, chunk) 2912 * 2913 * Outputs 2914 * (asoc, reply_msg, msg_up, timers, counters) 2915 * 2916 * The return value is the disposition of the chunk. 2917 */ 2918 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2919 const struct sctp_endpoint *ep, 2920 const struct sctp_association *asoc, 2921 const sctp_subtype_t type, 2922 void *arg, 2923 sctp_cmd_seq_t *commands) 2924 { 2925 sctp_ecnehdr_t *ecne; 2926 struct sctp_chunk *chunk = arg; 2927 2928 if (!sctp_vtag_verify(chunk, asoc)) 2929 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2930 2931 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2932 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2933 commands); 2934 2935 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2936 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2937 2938 /* If this is a newer ECNE than the last CWR packet we sent out */ 2939 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2940 SCTP_U32(ntohl(ecne->lowest_tsn))); 2941 2942 return SCTP_DISPOSITION_CONSUME; 2943 } 2944 2945 /* 2946 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2947 * 2948 * The SCTP endpoint MUST always acknowledge the reception of each valid 2949 * DATA chunk. 2950 * 2951 * The guidelines on delayed acknowledgement algorithm specified in 2952 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2953 * acknowledgement SHOULD be generated for at least every second packet 2954 * (not every second DATA chunk) received, and SHOULD be generated within 2955 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2956 * situations it may be beneficial for an SCTP transmitter to be more 2957 * conservative than the algorithms detailed in this document allow. 2958 * However, an SCTP transmitter MUST NOT be more aggressive than the 2959 * following algorithms allow. 2960 * 2961 * A SCTP receiver MUST NOT generate more than one SACK for every 2962 * incoming packet, other than to update the offered window as the 2963 * receiving application consumes new data. 2964 * 2965 * Verification Tag: 8.5 Verification Tag [Normal verification] 2966 * 2967 * Inputs 2968 * (endpoint, asoc, chunk) 2969 * 2970 * Outputs 2971 * (asoc, reply_msg, msg_up, timers, counters) 2972 * 2973 * The return value is the disposition of the chunk. 2974 */ 2975 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2976 const struct sctp_endpoint *ep, 2977 const struct sctp_association *asoc, 2978 const sctp_subtype_t type, 2979 void *arg, 2980 sctp_cmd_seq_t *commands) 2981 { 2982 struct sctp_chunk *chunk = arg; 2983 sctp_arg_t force = SCTP_NOFORCE(); 2984 int error; 2985 2986 if (!sctp_vtag_verify(chunk, asoc)) { 2987 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2988 SCTP_NULL()); 2989 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2990 } 2991 2992 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2993 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2994 commands); 2995 2996 error = sctp_eat_data(asoc, chunk, commands); 2997 switch (error) { 2998 case SCTP_IERROR_NO_ERROR: 2999 break; 3000 case SCTP_IERROR_HIGH_TSN: 3001 case SCTP_IERROR_BAD_STREAM: 3002 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3003 goto discard_noforce; 3004 case SCTP_IERROR_DUP_TSN: 3005 case SCTP_IERROR_IGNORE_TSN: 3006 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3007 goto discard_force; 3008 case SCTP_IERROR_NO_DATA: 3009 return SCTP_DISPOSITION_ABORT; 3010 case SCTP_IERROR_PROTO_VIOLATION: 3011 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3012 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3013 default: 3014 BUG(); 3015 } 3016 3017 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3018 force = SCTP_FORCE(); 3019 3020 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3021 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3022 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3023 } 3024 3025 /* If this is the last chunk in a packet, we need to count it 3026 * toward sack generation. Note that we need to SACK every 3027 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3028 * THEM. We elect to NOT generate SACK's if the chunk fails 3029 * the verification tag test. 3030 * 3031 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3032 * 3033 * The SCTP endpoint MUST always acknowledge the reception of 3034 * each valid DATA chunk. 3035 * 3036 * The guidelines on delayed acknowledgement algorithm 3037 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3038 * Specifically, an acknowledgement SHOULD be generated for at 3039 * least every second packet (not every second DATA chunk) 3040 * received, and SHOULD be generated within 200 ms of the 3041 * arrival of any unacknowledged DATA chunk. In some 3042 * situations it may be beneficial for an SCTP transmitter to 3043 * be more conservative than the algorithms detailed in this 3044 * document allow. However, an SCTP transmitter MUST NOT be 3045 * more aggressive than the following algorithms allow. 3046 */ 3047 if (chunk->end_of_packet) 3048 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3049 3050 return SCTP_DISPOSITION_CONSUME; 3051 3052 discard_force: 3053 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3054 * 3055 * When a packet arrives with duplicate DATA chunk(s) and with 3056 * no new DATA chunk(s), the endpoint MUST immediately send a 3057 * SACK with no delay. If a packet arrives with duplicate 3058 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3059 * MAY immediately send a SACK. Normally receipt of duplicate 3060 * DATA chunks will occur when the original SACK chunk was lost 3061 * and the peer's RTO has expired. The duplicate TSN number(s) 3062 * SHOULD be reported in the SACK as duplicate. 3063 */ 3064 /* In our case, we split the MAY SACK advice up whether or not 3065 * the last chunk is a duplicate.' 3066 */ 3067 if (chunk->end_of_packet) 3068 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3069 return SCTP_DISPOSITION_DISCARD; 3070 3071 discard_noforce: 3072 if (chunk->end_of_packet) 3073 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3074 3075 return SCTP_DISPOSITION_DISCARD; 3076 } 3077 3078 /* 3079 * sctp_sf_eat_data_fast_4_4 3080 * 3081 * Section: 4 (4) 3082 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3083 * DATA chunks without delay. 3084 * 3085 * Verification Tag: 8.5 Verification Tag [Normal verification] 3086 * Inputs 3087 * (endpoint, asoc, chunk) 3088 * 3089 * Outputs 3090 * (asoc, reply_msg, msg_up, timers, counters) 3091 * 3092 * The return value is the disposition of the chunk. 3093 */ 3094 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3095 const struct sctp_endpoint *ep, 3096 const struct sctp_association *asoc, 3097 const sctp_subtype_t type, 3098 void *arg, 3099 sctp_cmd_seq_t *commands) 3100 { 3101 struct sctp_chunk *chunk = arg; 3102 int error; 3103 3104 if (!sctp_vtag_verify(chunk, asoc)) { 3105 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3106 SCTP_NULL()); 3107 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3108 } 3109 3110 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3111 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3112 commands); 3113 3114 error = sctp_eat_data(asoc, chunk, commands); 3115 switch (error) { 3116 case SCTP_IERROR_NO_ERROR: 3117 case SCTP_IERROR_HIGH_TSN: 3118 case SCTP_IERROR_DUP_TSN: 3119 case SCTP_IERROR_IGNORE_TSN: 3120 case SCTP_IERROR_BAD_STREAM: 3121 break; 3122 case SCTP_IERROR_NO_DATA: 3123 return SCTP_DISPOSITION_ABORT; 3124 case SCTP_IERROR_PROTO_VIOLATION: 3125 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3126 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3127 default: 3128 BUG(); 3129 } 3130 3131 /* Go a head and force a SACK, since we are shutting down. */ 3132 3133 /* Implementor's Guide. 3134 * 3135 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3136 * respond to each received packet containing one or more DATA chunk(s) 3137 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3138 */ 3139 if (chunk->end_of_packet) { 3140 /* We must delay the chunk creation since the cumulative 3141 * TSN has not been updated yet. 3142 */ 3143 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3144 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3145 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3146 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3147 } 3148 3149 return SCTP_DISPOSITION_CONSUME; 3150 } 3151 3152 /* 3153 * Section: 6.2 Processing a Received SACK 3154 * D) Any time a SACK arrives, the endpoint performs the following: 3155 * 3156 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3157 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3158 * increasing, a SACK whose Cumulative TSN Ack is less than the 3159 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3160 * 3161 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3162 * of bytes still outstanding after processing the Cumulative TSN Ack 3163 * and the Gap Ack Blocks. 3164 * 3165 * iii) If the SACK is missing a TSN that was previously 3166 * acknowledged via a Gap Ack Block (e.g., the data receiver 3167 * reneged on the data), then mark the corresponding DATA chunk 3168 * as available for retransmit: Mark it as missing for fast 3169 * retransmit as described in Section 7.2.4 and if no retransmit 3170 * timer is running for the destination address to which the DATA 3171 * chunk was originally transmitted, then T3-rtx is started for 3172 * that destination address. 3173 * 3174 * Verification Tag: 8.5 Verification Tag [Normal verification] 3175 * 3176 * Inputs 3177 * (endpoint, asoc, chunk) 3178 * 3179 * Outputs 3180 * (asoc, reply_msg, msg_up, timers, counters) 3181 * 3182 * The return value is the disposition of the chunk. 3183 */ 3184 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3185 const struct sctp_endpoint *ep, 3186 const struct sctp_association *asoc, 3187 const sctp_subtype_t type, 3188 void *arg, 3189 sctp_cmd_seq_t *commands) 3190 { 3191 struct sctp_chunk *chunk = arg; 3192 sctp_sackhdr_t *sackh; 3193 __u32 ctsn; 3194 3195 if (!sctp_vtag_verify(chunk, asoc)) 3196 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3197 3198 /* Make sure that the SACK chunk has a valid length. */ 3199 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3200 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3201 commands); 3202 3203 /* Pull the SACK chunk from the data buffer */ 3204 sackh = sctp_sm_pull_sack(chunk); 3205 /* Was this a bogus SACK? */ 3206 if (!sackh) 3207 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3208 chunk->subh.sack_hdr = sackh; 3209 ctsn = ntohl(sackh->cum_tsn_ack); 3210 3211 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3212 * Ack Point, then drop the SACK. Since Cumulative TSN 3213 * Ack is monotonically increasing, a SACK whose 3214 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3215 * Point indicates an out-of-order SACK. 3216 */ 3217 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3218 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3219 asoc->ctsn_ack_point); 3220 3221 return SCTP_DISPOSITION_DISCARD; 3222 } 3223 3224 /* If Cumulative TSN Ack beyond the max tsn currently 3225 * send, terminating the association and respond to the 3226 * sender with an ABORT. 3227 */ 3228 if (!TSN_lt(ctsn, asoc->next_tsn)) 3229 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3230 3231 /* Return this SACK for further processing. */ 3232 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3233 3234 /* Note: We do the rest of the work on the PROCESS_SACK 3235 * sideeffect. 3236 */ 3237 return SCTP_DISPOSITION_CONSUME; 3238 } 3239 3240 /* 3241 * Generate an ABORT in response to a packet. 3242 * 3243 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3244 * 3245 * 8) The receiver should respond to the sender of the OOTB packet with 3246 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3247 * MUST fill in the Verification Tag field of the outbound packet 3248 * with the value found in the Verification Tag field of the OOTB 3249 * packet and set the T-bit in the Chunk Flags to indicate that the 3250 * Verification Tag is reflected. After sending this ABORT, the 3251 * receiver of the OOTB packet shall discard the OOTB packet and take 3252 * no further action. 3253 * 3254 * Verification Tag: 3255 * 3256 * The return value is the disposition of the chunk. 3257 */ 3258 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3259 const struct sctp_endpoint *ep, 3260 const struct sctp_association *asoc, 3261 const sctp_subtype_t type, 3262 void *arg, 3263 sctp_cmd_seq_t *commands) 3264 { 3265 struct sctp_packet *packet = NULL; 3266 struct sctp_chunk *chunk = arg; 3267 struct sctp_chunk *abort; 3268 3269 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3270 if (!packet) 3271 return SCTP_DISPOSITION_NOMEM; 3272 3273 /* Make an ABORT. The T bit will be set if the asoc 3274 * is NULL. 3275 */ 3276 abort = sctp_make_abort(asoc, chunk, 0); 3277 if (!abort) { 3278 sctp_ootb_pkt_free(packet); 3279 return SCTP_DISPOSITION_NOMEM; 3280 } 3281 3282 /* Reflect vtag if T-Bit is set */ 3283 if (sctp_test_T_bit(abort)) 3284 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3285 3286 /* Set the skb to the belonging sock for accounting. */ 3287 abort->skb->sk = ep->base.sk; 3288 3289 sctp_packet_append_chunk(packet, abort); 3290 3291 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3292 SCTP_PACKET(packet)); 3293 3294 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3295 3296 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3297 return SCTP_DISPOSITION_CONSUME; 3298 } 3299 3300 /* 3301 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3302 * event as ULP notification for each cause included in the chunk. 3303 * 3304 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3305 * 3306 * The return value is the disposition of the chunk. 3307 */ 3308 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3309 const struct sctp_endpoint *ep, 3310 const struct sctp_association *asoc, 3311 const sctp_subtype_t type, 3312 void *arg, 3313 sctp_cmd_seq_t *commands) 3314 { 3315 struct sctp_chunk *chunk = arg; 3316 sctp_errhdr_t *err; 3317 3318 if (!sctp_vtag_verify(chunk, asoc)) 3319 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3320 3321 /* Make sure that the ERROR chunk has a valid length. */ 3322 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3323 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3324 commands); 3325 sctp_walk_errors(err, chunk->chunk_hdr); 3326 if ((void *)err != (void *)chunk->chunk_end) 3327 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3328 (void *)err, commands); 3329 3330 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3331 SCTP_CHUNK(chunk)); 3332 3333 return SCTP_DISPOSITION_CONSUME; 3334 } 3335 3336 /* 3337 * Process an inbound SHUTDOWN ACK. 3338 * 3339 * From Section 9.2: 3340 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3341 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3342 * peer, and remove all record of the association. 3343 * 3344 * The return value is the disposition. 3345 */ 3346 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3347 const struct sctp_endpoint *ep, 3348 const struct sctp_association *asoc, 3349 const sctp_subtype_t type, 3350 void *arg, 3351 sctp_cmd_seq_t *commands) 3352 { 3353 struct sctp_chunk *chunk = arg; 3354 struct sctp_chunk *reply; 3355 struct sctp_ulpevent *ev; 3356 3357 if (!sctp_vtag_verify(chunk, asoc)) 3358 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3359 3360 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3361 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3362 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3363 commands); 3364 /* 10.2 H) SHUTDOWN COMPLETE notification 3365 * 3366 * When SCTP completes the shutdown procedures (section 9.2) this 3367 * notification is passed to the upper layer. 3368 */ 3369 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3370 0, 0, 0, NULL, GFP_ATOMIC); 3371 if (!ev) 3372 goto nomem; 3373 3374 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3375 reply = sctp_make_shutdown_complete(asoc, chunk); 3376 if (!reply) 3377 goto nomem_chunk; 3378 3379 /* Do all the commands now (after allocation), so that we 3380 * have consistent state if memory allocation failes 3381 */ 3382 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3383 3384 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3385 * stop the T2-shutdown timer, 3386 */ 3387 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3388 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3389 3390 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3391 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3392 3393 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3394 SCTP_STATE(SCTP_STATE_CLOSED)); 3395 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3396 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3397 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3398 3399 /* ...and remove all record of the association. */ 3400 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3401 return SCTP_DISPOSITION_DELETE_TCB; 3402 3403 nomem_chunk: 3404 sctp_ulpevent_free(ev); 3405 nomem: 3406 return SCTP_DISPOSITION_NOMEM; 3407 } 3408 3409 /* 3410 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3411 * 3412 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3413 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3414 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3415 * packet must fill in the Verification Tag field of the outbound 3416 * packet with the Verification Tag received in the SHUTDOWN ACK and 3417 * set the T-bit in the Chunk Flags to indicate that the Verification 3418 * Tag is reflected. 3419 * 3420 * 8) The receiver should respond to the sender of the OOTB packet with 3421 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3422 * MUST fill in the Verification Tag field of the outbound packet 3423 * with the value found in the Verification Tag field of the OOTB 3424 * packet and set the T-bit in the Chunk Flags to indicate that the 3425 * Verification Tag is reflected. After sending this ABORT, the 3426 * receiver of the OOTB packet shall discard the OOTB packet and take 3427 * no further action. 3428 */ 3429 sctp_disposition_t sctp_sf_ootb(struct net *net, 3430 const struct sctp_endpoint *ep, 3431 const struct sctp_association *asoc, 3432 const sctp_subtype_t type, 3433 void *arg, 3434 sctp_cmd_seq_t *commands) 3435 { 3436 struct sctp_chunk *chunk = arg; 3437 struct sk_buff *skb = chunk->skb; 3438 sctp_chunkhdr_t *ch; 3439 sctp_errhdr_t *err; 3440 __u8 *ch_end; 3441 int ootb_shut_ack = 0; 3442 int ootb_cookie_ack = 0; 3443 3444 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3445 3446 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3447 do { 3448 /* Report violation if the chunk is less then minimal */ 3449 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3450 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3451 commands); 3452 3453 /* Report violation if chunk len overflows */ 3454 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3455 if (ch_end > skb_tail_pointer(skb)) 3456 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3457 commands); 3458 3459 /* Now that we know we at least have a chunk header, 3460 * do things that are type appropriate. 3461 */ 3462 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3463 ootb_shut_ack = 1; 3464 3465 /* RFC 2960, Section 3.3.7 3466 * Moreover, under any circumstances, an endpoint that 3467 * receives an ABORT MUST NOT respond to that ABORT by 3468 * sending an ABORT of its own. 3469 */ 3470 if (SCTP_CID_ABORT == ch->type) 3471 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3472 3473 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3474 * or a COOKIE ACK the SCTP Packet should be silently 3475 * discarded. 3476 */ 3477 3478 if (SCTP_CID_COOKIE_ACK == ch->type) 3479 ootb_cookie_ack = 1; 3480 3481 if (SCTP_CID_ERROR == ch->type) { 3482 sctp_walk_errors(err, ch) { 3483 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3484 ootb_cookie_ack = 1; 3485 break; 3486 } 3487 } 3488 } 3489 3490 ch = (sctp_chunkhdr_t *) ch_end; 3491 } while (ch_end < skb_tail_pointer(skb)); 3492 3493 if (ootb_shut_ack) 3494 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3495 else if (ootb_cookie_ack) 3496 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3497 else 3498 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3499 } 3500 3501 /* 3502 * Handle an "Out of the blue" SHUTDOWN ACK. 3503 * 3504 * Section: 8.4 5, sctpimpguide 2.41. 3505 * 3506 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3507 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3508 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3509 * packet must fill in the Verification Tag field of the outbound 3510 * packet with the Verification Tag received in the SHUTDOWN ACK and 3511 * set the T-bit in the Chunk Flags to indicate that the Verification 3512 * Tag is reflected. 3513 * 3514 * Inputs 3515 * (endpoint, asoc, type, arg, commands) 3516 * 3517 * Outputs 3518 * (sctp_disposition_t) 3519 * 3520 * The return value is the disposition of the chunk. 3521 */ 3522 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3523 const struct sctp_endpoint *ep, 3524 const struct sctp_association *asoc, 3525 const sctp_subtype_t type, 3526 void *arg, 3527 sctp_cmd_seq_t *commands) 3528 { 3529 struct sctp_packet *packet = NULL; 3530 struct sctp_chunk *chunk = arg; 3531 struct sctp_chunk *shut; 3532 3533 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3534 if (!packet) 3535 return SCTP_DISPOSITION_NOMEM; 3536 3537 /* Make an SHUTDOWN_COMPLETE. 3538 * The T bit will be set if the asoc is NULL. 3539 */ 3540 shut = sctp_make_shutdown_complete(asoc, chunk); 3541 if (!shut) { 3542 sctp_ootb_pkt_free(packet); 3543 return SCTP_DISPOSITION_NOMEM; 3544 } 3545 3546 /* Reflect vtag if T-Bit is set */ 3547 if (sctp_test_T_bit(shut)) 3548 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3549 3550 /* Set the skb to the belonging sock for accounting. */ 3551 shut->skb->sk = ep->base.sk; 3552 3553 sctp_packet_append_chunk(packet, shut); 3554 3555 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3556 SCTP_PACKET(packet)); 3557 3558 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3559 3560 /* If the chunk length is invalid, we don't want to process 3561 * the reset of the packet. 3562 */ 3563 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3564 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3565 3566 /* We need to discard the rest of the packet to prevent 3567 * potential bomming attacks from additional bundled chunks. 3568 * This is documented in SCTP Threats ID. 3569 */ 3570 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3571 } 3572 3573 /* 3574 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3575 * 3576 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3577 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3578 * procedures in section 8.4 SHOULD be followed, in other words it 3579 * should be treated as an Out Of The Blue packet. 3580 * [This means that we do NOT check the Verification Tag on these 3581 * chunks. --piggy ] 3582 * 3583 */ 3584 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3585 const struct sctp_endpoint *ep, 3586 const struct sctp_association *asoc, 3587 const sctp_subtype_t type, 3588 void *arg, 3589 sctp_cmd_seq_t *commands) 3590 { 3591 struct sctp_chunk *chunk = arg; 3592 3593 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3594 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3595 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3596 commands); 3597 3598 /* Although we do have an association in this case, it corresponds 3599 * to a restarted association. So the packet is treated as an OOTB 3600 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3601 * called with a NULL association. 3602 */ 3603 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3604 3605 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3606 } 3607 3608 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3609 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3610 const struct sctp_endpoint *ep, 3611 const struct sctp_association *asoc, 3612 const sctp_subtype_t type, void *arg, 3613 sctp_cmd_seq_t *commands) 3614 { 3615 struct sctp_chunk *chunk = arg; 3616 struct sctp_chunk *asconf_ack = NULL; 3617 struct sctp_paramhdr *err_param = NULL; 3618 sctp_addiphdr_t *hdr; 3619 __u32 serial; 3620 3621 if (!sctp_vtag_verify(chunk, asoc)) { 3622 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3623 SCTP_NULL()); 3624 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3625 } 3626 3627 /* ADD-IP: Section 4.1.1 3628 * This chunk MUST be sent in an authenticated way by using 3629 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3630 * is received unauthenticated it MUST be silently discarded as 3631 * described in [I-D.ietf-tsvwg-sctp-auth]. 3632 */ 3633 if (!net->sctp.addip_noauth && !chunk->auth) 3634 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3635 3636 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3637 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3638 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3639 commands); 3640 3641 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3642 serial = ntohl(hdr->serial); 3643 3644 /* Verify the ASCONF chunk before processing it. */ 3645 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3646 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3647 (void *)err_param, commands); 3648 3649 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3650 * the endpoint stored in a new association variable 3651 * 'Peer-Serial-Number'. 3652 */ 3653 if (serial == asoc->peer.addip_serial + 1) { 3654 /* If this is the first instance of ASCONF in the packet, 3655 * we can clean our old ASCONF-ACKs. 3656 */ 3657 if (!chunk->has_asconf) 3658 sctp_assoc_clean_asconf_ack_cache(asoc); 3659 3660 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3661 * expected, process the ASCONF as described below and after 3662 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3663 * the response packet and cache a copy of it (in the event it 3664 * later needs to be retransmitted). 3665 * 3666 * Essentially, do V1-V5. 3667 */ 3668 asconf_ack = sctp_process_asconf((struct sctp_association *) 3669 asoc, chunk); 3670 if (!asconf_ack) 3671 return SCTP_DISPOSITION_NOMEM; 3672 } else if (serial < asoc->peer.addip_serial + 1) { 3673 /* ADDIP 5.2 E2) 3674 * If the value found in the Sequence Number is less than the 3675 * ('Peer- Sequence-Number' + 1), simply skip to the next 3676 * ASCONF, and include in the outbound response packet 3677 * any previously cached ASCONF-ACK response that was 3678 * sent and saved that matches the Sequence Number of the 3679 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3680 * Chunk exists. This will occur when an older ASCONF 3681 * arrives out of order. In such a case, the receiver 3682 * should skip the ASCONF Chunk and not include ASCONF-ACK 3683 * Chunk for that chunk. 3684 */ 3685 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3686 if (!asconf_ack) 3687 return SCTP_DISPOSITION_DISCARD; 3688 3689 /* Reset the transport so that we select the correct one 3690 * this time around. This is to make sure that we don't 3691 * accidentally use a stale transport that's been removed. 3692 */ 3693 asconf_ack->transport = NULL; 3694 } else { 3695 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3696 * it must be either a stale packet or from an attacker. 3697 */ 3698 return SCTP_DISPOSITION_DISCARD; 3699 } 3700 3701 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3702 * containing the ASCONF-ACK Chunks MUST be the source address of 3703 * the SCTP packet that held the ASCONF Chunks. 3704 * 3705 * To do this properly, we'll set the destination address of the chunk 3706 * and at the transmit time, will try look up the transport to use. 3707 * Since ASCONFs may be bundled, the correct transport may not be 3708 * created until we process the entire packet, thus this workaround. 3709 */ 3710 asconf_ack->dest = chunk->source; 3711 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3712 if (asoc->new_transport) { 3713 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3714 ((struct sctp_association *)asoc)->new_transport = NULL; 3715 } 3716 3717 return SCTP_DISPOSITION_CONSUME; 3718 } 3719 3720 /* 3721 * ADDIP Section 4.3 General rules for address manipulation 3722 * When building TLV parameters for the ASCONF Chunk that will add or 3723 * delete IP addresses the D0 to D13 rules should be applied: 3724 */ 3725 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3726 const struct sctp_endpoint *ep, 3727 const struct sctp_association *asoc, 3728 const sctp_subtype_t type, void *arg, 3729 sctp_cmd_seq_t *commands) 3730 { 3731 struct sctp_chunk *asconf_ack = arg; 3732 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3733 struct sctp_chunk *abort; 3734 struct sctp_paramhdr *err_param = NULL; 3735 sctp_addiphdr_t *addip_hdr; 3736 __u32 sent_serial, rcvd_serial; 3737 3738 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3739 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3740 SCTP_NULL()); 3741 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3742 } 3743 3744 /* ADD-IP, Section 4.1.2: 3745 * This chunk MUST be sent in an authenticated way by using 3746 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3747 * is received unauthenticated it MUST be silently discarded as 3748 * described in [I-D.ietf-tsvwg-sctp-auth]. 3749 */ 3750 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3751 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3752 3753 /* Make sure that the ADDIP chunk has a valid length. */ 3754 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3755 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3756 commands); 3757 3758 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3759 rcvd_serial = ntohl(addip_hdr->serial); 3760 3761 /* Verify the ASCONF-ACK chunk before processing it. */ 3762 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3763 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3764 (void *)err_param, commands); 3765 3766 if (last_asconf) { 3767 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3768 sent_serial = ntohl(addip_hdr->serial); 3769 } else { 3770 sent_serial = asoc->addip_serial - 1; 3771 } 3772 3773 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3774 * equal to the next serial number to be used but no ASCONF chunk is 3775 * outstanding the endpoint MUST ABORT the association. Note that a 3776 * sequence number is greater than if it is no more than 2^^31-1 3777 * larger than the current sequence number (using serial arithmetic). 3778 */ 3779 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3780 !(asoc->addip_last_asconf)) { 3781 abort = sctp_make_abort(asoc, asconf_ack, 3782 sizeof(sctp_errhdr_t)); 3783 if (abort) { 3784 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3785 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3786 SCTP_CHUNK(abort)); 3787 } 3788 /* We are going to ABORT, so we might as well stop 3789 * processing the rest of the chunks in the packet. 3790 */ 3791 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3792 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3793 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3794 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3795 SCTP_ERROR(ECONNABORTED)); 3796 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3797 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3798 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3799 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3800 return SCTP_DISPOSITION_ABORT; 3801 } 3802 3803 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3804 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3805 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3806 3807 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3808 asconf_ack)) { 3809 /* Successfully processed ASCONF_ACK. We can 3810 * release the next asconf if we have one. 3811 */ 3812 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3813 SCTP_NULL()); 3814 return SCTP_DISPOSITION_CONSUME; 3815 } 3816 3817 abort = sctp_make_abort(asoc, asconf_ack, 3818 sizeof(sctp_errhdr_t)); 3819 if (abort) { 3820 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3821 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3822 SCTP_CHUNK(abort)); 3823 } 3824 /* We are going to ABORT, so we might as well stop 3825 * processing the rest of the chunks in the packet. 3826 */ 3827 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3828 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3829 SCTP_ERROR(ECONNABORTED)); 3830 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3831 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3832 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3833 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3834 return SCTP_DISPOSITION_ABORT; 3835 } 3836 3837 return SCTP_DISPOSITION_DISCARD; 3838 } 3839 3840 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 3841 sctp_disposition_t sctp_sf_do_reconf(struct net *net, 3842 const struct sctp_endpoint *ep, 3843 const struct sctp_association *asoc, 3844 const sctp_subtype_t type, void *arg, 3845 sctp_cmd_seq_t *commands) 3846 { 3847 struct sctp_paramhdr *err_param = NULL; 3848 struct sctp_chunk *chunk = arg; 3849 struct sctp_reconf_chunk *hdr; 3850 union sctp_params param; 3851 3852 if (!sctp_vtag_verify(chunk, asoc)) { 3853 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3854 SCTP_NULL()); 3855 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3856 } 3857 3858 /* Make sure that the RECONF chunk has a valid length. */ 3859 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 3860 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3861 commands); 3862 3863 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 3864 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3865 (void *)err_param, commands); 3866 3867 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 3868 sctp_walk_params(param, hdr, params) { 3869 struct sctp_chunk *reply = NULL; 3870 struct sctp_ulpevent *ev = NULL; 3871 3872 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 3873 reply = sctp_process_strreset_outreq( 3874 (struct sctp_association *)asoc, param, &ev); 3875 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 3876 reply = sctp_process_strreset_inreq( 3877 (struct sctp_association *)asoc, param, &ev); 3878 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 3879 reply = sctp_process_strreset_tsnreq( 3880 (struct sctp_association *)asoc, param, &ev); 3881 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 3882 reply = sctp_process_strreset_addstrm_out( 3883 (struct sctp_association *)asoc, param, &ev); 3884 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 3885 reply = sctp_process_strreset_addstrm_in( 3886 (struct sctp_association *)asoc, param, &ev); 3887 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 3888 reply = sctp_process_strreset_resp( 3889 (struct sctp_association *)asoc, param, &ev); 3890 3891 if (ev) 3892 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3893 SCTP_ULPEVENT(ev)); 3894 3895 if (reply) 3896 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3897 SCTP_CHUNK(reply)); 3898 } 3899 3900 return SCTP_DISPOSITION_CONSUME; 3901 } 3902 3903 /* 3904 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3905 * 3906 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3907 * its cumulative TSN point to the value carried in the FORWARD TSN 3908 * chunk, and then MUST further advance its cumulative TSN point locally 3909 * if possible. 3910 * After the above processing, the data receiver MUST stop reporting any 3911 * missing TSNs earlier than or equal to the new cumulative TSN point. 3912 * 3913 * Verification Tag: 8.5 Verification Tag [Normal verification] 3914 * 3915 * The return value is the disposition of the chunk. 3916 */ 3917 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3918 const struct sctp_endpoint *ep, 3919 const struct sctp_association *asoc, 3920 const sctp_subtype_t type, 3921 void *arg, 3922 sctp_cmd_seq_t *commands) 3923 { 3924 struct sctp_chunk *chunk = arg; 3925 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3926 struct sctp_fwdtsn_skip *skip; 3927 __u16 len; 3928 __u32 tsn; 3929 3930 if (!sctp_vtag_verify(chunk, asoc)) { 3931 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3932 SCTP_NULL()); 3933 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3934 } 3935 3936 if (!asoc->peer.prsctp_capable) 3937 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 3938 3939 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3940 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3941 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3942 commands); 3943 3944 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3945 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3946 len = ntohs(chunk->chunk_hdr->length); 3947 len -= sizeof(struct sctp_chunkhdr); 3948 skb_pull(chunk->skb, len); 3949 3950 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3951 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3952 3953 /* The TSN is too high--silently discard the chunk and count on it 3954 * getting retransmitted later. 3955 */ 3956 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3957 goto discard_noforce; 3958 3959 /* Silently discard the chunk if stream-id is not valid */ 3960 sctp_walk_fwdtsn(skip, chunk) { 3961 if (ntohs(skip->stream) >= asoc->stream->incnt) 3962 goto discard_noforce; 3963 } 3964 3965 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3966 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3967 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3968 SCTP_CHUNK(chunk)); 3969 3970 /* Count this as receiving DATA. */ 3971 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3972 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3973 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3974 } 3975 3976 /* FIXME: For now send a SACK, but DATA processing may 3977 * send another. 3978 */ 3979 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3980 3981 return SCTP_DISPOSITION_CONSUME; 3982 3983 discard_noforce: 3984 return SCTP_DISPOSITION_DISCARD; 3985 } 3986 3987 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3988 struct net *net, 3989 const struct sctp_endpoint *ep, 3990 const struct sctp_association *asoc, 3991 const sctp_subtype_t type, 3992 void *arg, 3993 sctp_cmd_seq_t *commands) 3994 { 3995 struct sctp_chunk *chunk = arg; 3996 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3997 struct sctp_fwdtsn_skip *skip; 3998 __u16 len; 3999 __u32 tsn; 4000 4001 if (!sctp_vtag_verify(chunk, asoc)) { 4002 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4003 SCTP_NULL()); 4004 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4005 } 4006 4007 if (!asoc->peer.prsctp_capable) 4008 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4009 4010 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4011 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 4012 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4013 commands); 4014 4015 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4016 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4017 len = ntohs(chunk->chunk_hdr->length); 4018 len -= sizeof(struct sctp_chunkhdr); 4019 skb_pull(chunk->skb, len); 4020 4021 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4022 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4023 4024 /* The TSN is too high--silently discard the chunk and count on it 4025 * getting retransmitted later. 4026 */ 4027 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4028 goto gen_shutdown; 4029 4030 /* Silently discard the chunk if stream-id is not valid */ 4031 sctp_walk_fwdtsn(skip, chunk) { 4032 if (ntohs(skip->stream) >= asoc->stream->incnt) 4033 goto gen_shutdown; 4034 } 4035 4036 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4037 if (len > sizeof(struct sctp_fwdtsn_hdr)) 4038 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4039 SCTP_CHUNK(chunk)); 4040 4041 /* Go a head and force a SACK, since we are shutting down. */ 4042 gen_shutdown: 4043 /* Implementor's Guide. 4044 * 4045 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4046 * respond to each received packet containing one or more DATA chunk(s) 4047 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4048 */ 4049 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4050 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4051 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4052 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4053 4054 return SCTP_DISPOSITION_CONSUME; 4055 } 4056 4057 /* 4058 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4059 * 4060 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4061 * Identifier field. If this algorithm was not specified by the 4062 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4063 * during association setup, the AUTH chunk and all chunks after it MUST 4064 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4065 * defined in Section 4.1. 4066 * 4067 * If an endpoint with no shared key receives a Shared Key Identifier 4068 * other than 0, it MUST silently discard all authenticated chunks. If 4069 * the endpoint has at least one endpoint pair shared key for the peer, 4070 * it MUST use the key specified by the Shared Key Identifier if a 4071 * key has been configured for that Shared Key Identifier. If no 4072 * endpoint pair shared key has been configured for that Shared Key 4073 * Identifier, all authenticated chunks MUST be silently discarded. 4074 * 4075 * Verification Tag: 8.5 Verification Tag [Normal verification] 4076 * 4077 * The return value is the disposition of the chunk. 4078 */ 4079 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 4080 const struct sctp_endpoint *ep, 4081 const struct sctp_association *asoc, 4082 const sctp_subtype_t type, 4083 struct sctp_chunk *chunk) 4084 { 4085 struct sctp_authhdr *auth_hdr; 4086 struct sctp_hmac *hmac; 4087 unsigned int sig_len; 4088 __u16 key_id; 4089 __u8 *save_digest; 4090 __u8 *digest; 4091 4092 /* Pull in the auth header, so we can do some more verification */ 4093 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4094 chunk->subh.auth_hdr = auth_hdr; 4095 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4096 4097 /* Make sure that we support the HMAC algorithm from the auth 4098 * chunk. 4099 */ 4100 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4101 return SCTP_IERROR_AUTH_BAD_HMAC; 4102 4103 /* Make sure that the provided shared key identifier has been 4104 * configured 4105 */ 4106 key_id = ntohs(auth_hdr->shkey_id); 4107 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4108 return SCTP_IERROR_AUTH_BAD_KEYID; 4109 4110 4111 /* Make sure that the length of the signature matches what 4112 * we expect. 4113 */ 4114 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4115 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4116 if (sig_len != hmac->hmac_len) 4117 return SCTP_IERROR_PROTO_VIOLATION; 4118 4119 /* Now that we've done validation checks, we can compute and 4120 * verify the hmac. The steps involved are: 4121 * 1. Save the digest from the chunk. 4122 * 2. Zero out the digest in the chunk. 4123 * 3. Compute the new digest 4124 * 4. Compare saved and new digests. 4125 */ 4126 digest = auth_hdr->hmac; 4127 skb_pull(chunk->skb, sig_len); 4128 4129 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4130 if (!save_digest) 4131 goto nomem; 4132 4133 memset(digest, 0, sig_len); 4134 4135 sctp_auth_calculate_hmac(asoc, chunk->skb, 4136 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4137 GFP_ATOMIC); 4138 4139 /* Discard the packet if the digests do not match */ 4140 if (memcmp(save_digest, digest, sig_len)) { 4141 kfree(save_digest); 4142 return SCTP_IERROR_BAD_SIG; 4143 } 4144 4145 kfree(save_digest); 4146 chunk->auth = 1; 4147 4148 return SCTP_IERROR_NO_ERROR; 4149 nomem: 4150 return SCTP_IERROR_NOMEM; 4151 } 4152 4153 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4154 const struct sctp_endpoint *ep, 4155 const struct sctp_association *asoc, 4156 const sctp_subtype_t type, 4157 void *arg, 4158 sctp_cmd_seq_t *commands) 4159 { 4160 struct sctp_authhdr *auth_hdr; 4161 struct sctp_chunk *chunk = arg; 4162 struct sctp_chunk *err_chunk; 4163 sctp_ierror_t error; 4164 4165 /* Make sure that the peer has AUTH capable */ 4166 if (!asoc->peer.auth_capable) 4167 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4168 4169 if (!sctp_vtag_verify(chunk, asoc)) { 4170 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4171 SCTP_NULL()); 4172 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4173 } 4174 4175 /* Make sure that the AUTH chunk has valid length. */ 4176 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4177 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4178 commands); 4179 4180 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4181 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4182 switch (error) { 4183 case SCTP_IERROR_AUTH_BAD_HMAC: 4184 /* Generate the ERROR chunk and discard the rest 4185 * of the packet 4186 */ 4187 err_chunk = sctp_make_op_error(asoc, chunk, 4188 SCTP_ERROR_UNSUP_HMAC, 4189 &auth_hdr->hmac_id, 4190 sizeof(__u16), 0); 4191 if (err_chunk) { 4192 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4193 SCTP_CHUNK(err_chunk)); 4194 } 4195 /* Fall Through */ 4196 case SCTP_IERROR_AUTH_BAD_KEYID: 4197 case SCTP_IERROR_BAD_SIG: 4198 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4199 4200 case SCTP_IERROR_PROTO_VIOLATION: 4201 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4202 commands); 4203 4204 case SCTP_IERROR_NOMEM: 4205 return SCTP_DISPOSITION_NOMEM; 4206 4207 default: /* Prevent gcc warnings */ 4208 break; 4209 } 4210 4211 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4212 struct sctp_ulpevent *ev; 4213 4214 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4215 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4216 4217 if (!ev) 4218 return -ENOMEM; 4219 4220 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4221 SCTP_ULPEVENT(ev)); 4222 } 4223 4224 return SCTP_DISPOSITION_CONSUME; 4225 } 4226 4227 /* 4228 * Process an unknown chunk. 4229 * 4230 * Section: 3.2. Also, 2.1 in the implementor's guide. 4231 * 4232 * Chunk Types are encoded such that the highest-order two bits specify 4233 * the action that must be taken if the processing endpoint does not 4234 * recognize the Chunk Type. 4235 * 4236 * 00 - Stop processing this SCTP packet and discard it, do not process 4237 * any further chunks within it. 4238 * 4239 * 01 - Stop processing this SCTP packet and discard it, do not process 4240 * any further chunks within it, and report the unrecognized 4241 * chunk in an 'Unrecognized Chunk Type'. 4242 * 4243 * 10 - Skip this chunk and continue processing. 4244 * 4245 * 11 - Skip this chunk and continue processing, but report in an ERROR 4246 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4247 * 4248 * The return value is the disposition of the chunk. 4249 */ 4250 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4251 const struct sctp_endpoint *ep, 4252 const struct sctp_association *asoc, 4253 const sctp_subtype_t type, 4254 void *arg, 4255 sctp_cmd_seq_t *commands) 4256 { 4257 struct sctp_chunk *unk_chunk = arg; 4258 struct sctp_chunk *err_chunk; 4259 sctp_chunkhdr_t *hdr; 4260 4261 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4262 4263 if (!sctp_vtag_verify(unk_chunk, asoc)) 4264 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4265 4266 /* Make sure that the chunk has a valid length. 4267 * Since we don't know the chunk type, we use a general 4268 * chunkhdr structure to make a comparison. 4269 */ 4270 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4271 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4272 commands); 4273 4274 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4275 case SCTP_CID_ACTION_DISCARD: 4276 /* Discard the packet. */ 4277 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4278 case SCTP_CID_ACTION_DISCARD_ERR: 4279 /* Generate an ERROR chunk as response. */ 4280 hdr = unk_chunk->chunk_hdr; 4281 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4282 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4283 SCTP_PAD4(ntohs(hdr->length)), 4284 0); 4285 if (err_chunk) { 4286 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4287 SCTP_CHUNK(err_chunk)); 4288 } 4289 4290 /* Discard the packet. */ 4291 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4292 return SCTP_DISPOSITION_CONSUME; 4293 case SCTP_CID_ACTION_SKIP: 4294 /* Skip the chunk. */ 4295 return SCTP_DISPOSITION_DISCARD; 4296 case SCTP_CID_ACTION_SKIP_ERR: 4297 /* Generate an ERROR chunk as response. */ 4298 hdr = unk_chunk->chunk_hdr; 4299 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4300 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4301 SCTP_PAD4(ntohs(hdr->length)), 4302 0); 4303 if (err_chunk) { 4304 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4305 SCTP_CHUNK(err_chunk)); 4306 } 4307 /* Skip the chunk. */ 4308 return SCTP_DISPOSITION_CONSUME; 4309 default: 4310 break; 4311 } 4312 4313 return SCTP_DISPOSITION_DISCARD; 4314 } 4315 4316 /* 4317 * Discard the chunk. 4318 * 4319 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4320 * [Too numerous to mention...] 4321 * Verification Tag: No verification needed. 4322 * Inputs 4323 * (endpoint, asoc, chunk) 4324 * 4325 * Outputs 4326 * (asoc, reply_msg, msg_up, timers, counters) 4327 * 4328 * The return value is the disposition of the chunk. 4329 */ 4330 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4331 const struct sctp_endpoint *ep, 4332 const struct sctp_association *asoc, 4333 const sctp_subtype_t type, 4334 void *arg, 4335 sctp_cmd_seq_t *commands) 4336 { 4337 struct sctp_chunk *chunk = arg; 4338 4339 /* Make sure that the chunk has a valid length. 4340 * Since we don't know the chunk type, we use a general 4341 * chunkhdr structure to make a comparison. 4342 */ 4343 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4344 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4345 commands); 4346 4347 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4348 4349 return SCTP_DISPOSITION_DISCARD; 4350 } 4351 4352 /* 4353 * Discard the whole packet. 4354 * 4355 * Section: 8.4 2) 4356 * 4357 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4358 * silently discard the OOTB packet and take no further action. 4359 * 4360 * Verification Tag: No verification necessary 4361 * 4362 * Inputs 4363 * (endpoint, asoc, chunk) 4364 * 4365 * Outputs 4366 * (asoc, reply_msg, msg_up, timers, counters) 4367 * 4368 * The return value is the disposition of the chunk. 4369 */ 4370 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4371 const struct sctp_endpoint *ep, 4372 const struct sctp_association *asoc, 4373 const sctp_subtype_t type, 4374 void *arg, 4375 sctp_cmd_seq_t *commands) 4376 { 4377 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4378 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4379 4380 return SCTP_DISPOSITION_CONSUME; 4381 } 4382 4383 4384 /* 4385 * The other end is violating protocol. 4386 * 4387 * Section: Not specified 4388 * Verification Tag: Not specified 4389 * Inputs 4390 * (endpoint, asoc, chunk) 4391 * 4392 * Outputs 4393 * (asoc, reply_msg, msg_up, timers, counters) 4394 * 4395 * We simply tag the chunk as a violation. The state machine will log 4396 * the violation and continue. 4397 */ 4398 sctp_disposition_t sctp_sf_violation(struct net *net, 4399 const struct sctp_endpoint *ep, 4400 const struct sctp_association *asoc, 4401 const sctp_subtype_t type, 4402 void *arg, 4403 sctp_cmd_seq_t *commands) 4404 { 4405 struct sctp_chunk *chunk = arg; 4406 4407 /* Make sure that the chunk has a valid length. */ 4408 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4409 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4410 commands); 4411 4412 return SCTP_DISPOSITION_VIOLATION; 4413 } 4414 4415 /* 4416 * Common function to handle a protocol violation. 4417 */ 4418 static sctp_disposition_t sctp_sf_abort_violation( 4419 struct net *net, 4420 const struct sctp_endpoint *ep, 4421 const struct sctp_association *asoc, 4422 void *arg, 4423 sctp_cmd_seq_t *commands, 4424 const __u8 *payload, 4425 const size_t paylen) 4426 { 4427 struct sctp_packet *packet = NULL; 4428 struct sctp_chunk *chunk = arg; 4429 struct sctp_chunk *abort = NULL; 4430 4431 /* SCTP-AUTH, Section 6.3: 4432 * It should be noted that if the receiver wants to tear 4433 * down an association in an authenticated way only, the 4434 * handling of malformed packets should not result in 4435 * tearing down the association. 4436 * 4437 * This means that if we only want to abort associations 4438 * in an authenticated way (i.e AUTH+ABORT), then we 4439 * can't destroy this association just because the packet 4440 * was malformed. 4441 */ 4442 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4443 goto discard; 4444 4445 /* Make the abort chunk. */ 4446 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4447 if (!abort) 4448 goto nomem; 4449 4450 if (asoc) { 4451 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4452 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4453 !asoc->peer.i.init_tag) { 4454 sctp_initack_chunk_t *initack; 4455 4456 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4457 if (!sctp_chunk_length_valid(chunk, 4458 sizeof(sctp_initack_chunk_t))) 4459 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4460 else { 4461 unsigned int inittag; 4462 4463 inittag = ntohl(initack->init_hdr.init_tag); 4464 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4465 SCTP_U32(inittag)); 4466 } 4467 } 4468 4469 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4470 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4471 4472 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4473 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4474 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4475 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4476 SCTP_ERROR(ECONNREFUSED)); 4477 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4478 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4479 } else { 4480 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4481 SCTP_ERROR(ECONNABORTED)); 4482 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4483 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4484 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4485 } 4486 } else { 4487 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4488 4489 if (!packet) 4490 goto nomem_pkt; 4491 4492 if (sctp_test_T_bit(abort)) 4493 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4494 4495 abort->skb->sk = ep->base.sk; 4496 4497 sctp_packet_append_chunk(packet, abort); 4498 4499 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4500 SCTP_PACKET(packet)); 4501 4502 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4503 } 4504 4505 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4506 4507 discard: 4508 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4509 return SCTP_DISPOSITION_ABORT; 4510 4511 nomem_pkt: 4512 sctp_chunk_free(abort); 4513 nomem: 4514 return SCTP_DISPOSITION_NOMEM; 4515 } 4516 4517 /* 4518 * Handle a protocol violation when the chunk length is invalid. 4519 * "Invalid" length is identified as smaller than the minimal length a 4520 * given chunk can be. For example, a SACK chunk has invalid length 4521 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4522 * 4523 * We inform the other end by sending an ABORT with a Protocol Violation 4524 * error code. 4525 * 4526 * Section: Not specified 4527 * Verification Tag: Nothing to do 4528 * Inputs 4529 * (endpoint, asoc, chunk) 4530 * 4531 * Outputs 4532 * (reply_msg, msg_up, counters) 4533 * 4534 * Generate an ABORT chunk and terminate the association. 4535 */ 4536 static sctp_disposition_t sctp_sf_violation_chunklen( 4537 struct net *net, 4538 const struct sctp_endpoint *ep, 4539 const struct sctp_association *asoc, 4540 const sctp_subtype_t type, 4541 void *arg, 4542 sctp_cmd_seq_t *commands) 4543 { 4544 static const char err_str[] = "The following chunk had invalid length:"; 4545 4546 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4547 sizeof(err_str)); 4548 } 4549 4550 /* 4551 * Handle a protocol violation when the parameter length is invalid. 4552 * If the length is smaller than the minimum length of a given parameter, 4553 * or accumulated length in multi parameters exceeds the end of the chunk, 4554 * the length is considered as invalid. 4555 */ 4556 static sctp_disposition_t sctp_sf_violation_paramlen( 4557 struct net *net, 4558 const struct sctp_endpoint *ep, 4559 const struct sctp_association *asoc, 4560 const sctp_subtype_t type, 4561 void *arg, void *ext, 4562 sctp_cmd_seq_t *commands) 4563 { 4564 struct sctp_chunk *chunk = arg; 4565 struct sctp_paramhdr *param = ext; 4566 struct sctp_chunk *abort = NULL; 4567 4568 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4569 goto discard; 4570 4571 /* Make the abort chunk. */ 4572 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4573 if (!abort) 4574 goto nomem; 4575 4576 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4577 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4578 4579 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4580 SCTP_ERROR(ECONNABORTED)); 4581 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4582 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4583 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4584 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4585 4586 discard: 4587 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4588 return SCTP_DISPOSITION_ABORT; 4589 nomem: 4590 return SCTP_DISPOSITION_NOMEM; 4591 } 4592 4593 /* Handle a protocol violation when the peer trying to advance the 4594 * cumulative tsn ack to a point beyond the max tsn currently sent. 4595 * 4596 * We inform the other end by sending an ABORT with a Protocol Violation 4597 * error code. 4598 */ 4599 static sctp_disposition_t sctp_sf_violation_ctsn( 4600 struct net *net, 4601 const struct sctp_endpoint *ep, 4602 const struct sctp_association *asoc, 4603 const sctp_subtype_t type, 4604 void *arg, 4605 sctp_cmd_seq_t *commands) 4606 { 4607 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4608 4609 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4610 sizeof(err_str)); 4611 } 4612 4613 /* Handle protocol violation of an invalid chunk bundling. For example, 4614 * when we have an association and we receive bundled INIT-ACK, or 4615 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4616 * statement from the specs. Additionally, there might be an attacker 4617 * on the path and we may not want to continue this communication. 4618 */ 4619 static sctp_disposition_t sctp_sf_violation_chunk( 4620 struct net *net, 4621 const struct sctp_endpoint *ep, 4622 const struct sctp_association *asoc, 4623 const sctp_subtype_t type, 4624 void *arg, 4625 sctp_cmd_seq_t *commands) 4626 { 4627 static const char err_str[] = "The following chunk violates protocol:"; 4628 4629 if (!asoc) 4630 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4631 4632 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4633 sizeof(err_str)); 4634 } 4635 /*************************************************************************** 4636 * These are the state functions for handling primitive (Section 10) events. 4637 ***************************************************************************/ 4638 /* 4639 * sctp_sf_do_prm_asoc 4640 * 4641 * Section: 10.1 ULP-to-SCTP 4642 * B) Associate 4643 * 4644 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4645 * outbound stream count) 4646 * -> association id [,destination transport addr list] [,outbound stream 4647 * count] 4648 * 4649 * This primitive allows the upper layer to initiate an association to a 4650 * specific peer endpoint. 4651 * 4652 * The peer endpoint shall be specified by one of the transport addresses 4653 * which defines the endpoint (see Section 1.4). If the local SCTP 4654 * instance has not been initialized, the ASSOCIATE is considered an 4655 * error. 4656 * [This is not relevant for the kernel implementation since we do all 4657 * initialization at boot time. It we hadn't initialized we wouldn't 4658 * get anywhere near this code.] 4659 * 4660 * An association id, which is a local handle to the SCTP association, 4661 * will be returned on successful establishment of the association. If 4662 * SCTP is not able to open an SCTP association with the peer endpoint, 4663 * an error is returned. 4664 * [In the kernel implementation, the struct sctp_association needs to 4665 * be created BEFORE causing this primitive to run.] 4666 * 4667 * Other association parameters may be returned, including the 4668 * complete destination transport addresses of the peer as well as the 4669 * outbound stream count of the local endpoint. One of the transport 4670 * address from the returned destination addresses will be selected by 4671 * the local endpoint as default primary path for sending SCTP packets 4672 * to this peer. The returned "destination transport addr list" can 4673 * be used by the ULP to change the default primary path or to force 4674 * sending a packet to a specific transport address. [All of this 4675 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4676 * function.] 4677 * 4678 * Mandatory attributes: 4679 * 4680 * o local SCTP instance name - obtained from the INITIALIZE operation. 4681 * [This is the argument asoc.] 4682 * o destination transport addr - specified as one of the transport 4683 * addresses of the peer endpoint with which the association is to be 4684 * established. 4685 * [This is asoc->peer.active_path.] 4686 * o outbound stream count - the number of outbound streams the ULP 4687 * would like to open towards this peer endpoint. 4688 * [BUG: This is not currently implemented.] 4689 * Optional attributes: 4690 * 4691 * None. 4692 * 4693 * The return value is a disposition. 4694 */ 4695 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4696 const struct sctp_endpoint *ep, 4697 const struct sctp_association *asoc, 4698 const sctp_subtype_t type, 4699 void *arg, 4700 sctp_cmd_seq_t *commands) 4701 { 4702 struct sctp_chunk *repl; 4703 struct sctp_association *my_asoc; 4704 4705 /* The comment below says that we enter COOKIE-WAIT AFTER 4706 * sending the INIT, but that doesn't actually work in our 4707 * implementation... 4708 */ 4709 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4710 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4711 4712 /* RFC 2960 5.1 Normal Establishment of an Association 4713 * 4714 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4715 * must provide its Verification Tag (Tag_A) in the Initiate 4716 * Tag field. Tag_A SHOULD be a random number in the range of 4717 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4718 */ 4719 4720 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4721 if (!repl) 4722 goto nomem; 4723 4724 /* Choose transport for INIT. */ 4725 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4726 SCTP_CHUNK(repl)); 4727 4728 /* Cast away the const modifier, as we want to just 4729 * rerun it through as a sideffect. 4730 */ 4731 my_asoc = (struct sctp_association *)asoc; 4732 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4733 4734 /* After sending the INIT, "A" starts the T1-init timer and 4735 * enters the COOKIE-WAIT state. 4736 */ 4737 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4738 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4739 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4740 return SCTP_DISPOSITION_CONSUME; 4741 4742 nomem: 4743 return SCTP_DISPOSITION_NOMEM; 4744 } 4745 4746 /* 4747 * Process the SEND primitive. 4748 * 4749 * Section: 10.1 ULP-to-SCTP 4750 * E) Send 4751 * 4752 * Format: SEND(association id, buffer address, byte count [,context] 4753 * [,stream id] [,life time] [,destination transport address] 4754 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4755 * -> result 4756 * 4757 * This is the main method to send user data via SCTP. 4758 * 4759 * Mandatory attributes: 4760 * 4761 * o association id - local handle to the SCTP association 4762 * 4763 * o buffer address - the location where the user message to be 4764 * transmitted is stored; 4765 * 4766 * o byte count - The size of the user data in number of bytes; 4767 * 4768 * Optional attributes: 4769 * 4770 * o context - an optional 32 bit integer that will be carried in the 4771 * sending failure notification to the ULP if the transportation of 4772 * this User Message fails. 4773 * 4774 * o stream id - to indicate which stream to send the data on. If not 4775 * specified, stream 0 will be used. 4776 * 4777 * o life time - specifies the life time of the user data. The user data 4778 * will not be sent by SCTP after the life time expires. This 4779 * parameter can be used to avoid efforts to transmit stale 4780 * user messages. SCTP notifies the ULP if the data cannot be 4781 * initiated to transport (i.e. sent to the destination via SCTP's 4782 * send primitive) within the life time variable. However, the 4783 * user data will be transmitted if SCTP has attempted to transmit a 4784 * chunk before the life time expired. 4785 * 4786 * o destination transport address - specified as one of the destination 4787 * transport addresses of the peer endpoint to which this packet 4788 * should be sent. Whenever possible, SCTP should use this destination 4789 * transport address for sending the packets, instead of the current 4790 * primary path. 4791 * 4792 * o unorder flag - this flag, if present, indicates that the user 4793 * would like the data delivered in an unordered fashion to the peer 4794 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4795 * message). 4796 * 4797 * o no-bundle flag - instructs SCTP not to bundle this user data with 4798 * other outbound DATA chunks. SCTP MAY still bundle even when 4799 * this flag is present, when faced with network congestion. 4800 * 4801 * o payload protocol-id - A 32 bit unsigned integer that is to be 4802 * passed to the peer indicating the type of payload protocol data 4803 * being transmitted. This value is passed as opaque data by SCTP. 4804 * 4805 * The return value is the disposition. 4806 */ 4807 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4808 const struct sctp_endpoint *ep, 4809 const struct sctp_association *asoc, 4810 const sctp_subtype_t type, 4811 void *arg, 4812 sctp_cmd_seq_t *commands) 4813 { 4814 struct sctp_datamsg *msg = arg; 4815 4816 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4817 return SCTP_DISPOSITION_CONSUME; 4818 } 4819 4820 /* 4821 * Process the SHUTDOWN primitive. 4822 * 4823 * Section: 10.1: 4824 * C) Shutdown 4825 * 4826 * Format: SHUTDOWN(association id) 4827 * -> result 4828 * 4829 * Gracefully closes an association. Any locally queued user data 4830 * will be delivered to the peer. The association will be terminated only 4831 * after the peer acknowledges all the SCTP packets sent. A success code 4832 * will be returned on successful termination of the association. If 4833 * attempting to terminate the association results in a failure, an error 4834 * code shall be returned. 4835 * 4836 * Mandatory attributes: 4837 * 4838 * o association id - local handle to the SCTP association 4839 * 4840 * Optional attributes: 4841 * 4842 * None. 4843 * 4844 * The return value is the disposition. 4845 */ 4846 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4847 struct net *net, 4848 const struct sctp_endpoint *ep, 4849 const struct sctp_association *asoc, 4850 const sctp_subtype_t type, 4851 void *arg, 4852 sctp_cmd_seq_t *commands) 4853 { 4854 int disposition; 4855 4856 /* From 9.2 Shutdown of an Association 4857 * Upon receipt of the SHUTDOWN primitive from its upper 4858 * layer, the endpoint enters SHUTDOWN-PENDING state and 4859 * remains there until all outstanding data has been 4860 * acknowledged by its peer. The endpoint accepts no new data 4861 * from its upper layer, but retransmits data to the far end 4862 * if necessary to fill gaps. 4863 */ 4864 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4865 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4866 4867 disposition = SCTP_DISPOSITION_CONSUME; 4868 if (sctp_outq_is_empty(&asoc->outqueue)) { 4869 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4870 arg, commands); 4871 } 4872 return disposition; 4873 } 4874 4875 /* 4876 * Process the ABORT primitive. 4877 * 4878 * Section: 10.1: 4879 * C) Abort 4880 * 4881 * Format: Abort(association id [, cause code]) 4882 * -> result 4883 * 4884 * Ungracefully closes an association. Any locally queued user data 4885 * will be discarded and an ABORT chunk is sent to the peer. A success code 4886 * will be returned on successful abortion of the association. If 4887 * attempting to abort the association results in a failure, an error 4888 * code shall be returned. 4889 * 4890 * Mandatory attributes: 4891 * 4892 * o association id - local handle to the SCTP association 4893 * 4894 * Optional attributes: 4895 * 4896 * o cause code - reason of the abort to be passed to the peer 4897 * 4898 * None. 4899 * 4900 * The return value is the disposition. 4901 */ 4902 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4903 struct net *net, 4904 const struct sctp_endpoint *ep, 4905 const struct sctp_association *asoc, 4906 const sctp_subtype_t type, 4907 void *arg, 4908 sctp_cmd_seq_t *commands) 4909 { 4910 /* From 9.1 Abort of an Association 4911 * Upon receipt of the ABORT primitive from its upper 4912 * layer, the endpoint enters CLOSED state and 4913 * discard all outstanding data has been 4914 * acknowledged by its peer. The endpoint accepts no new data 4915 * from its upper layer, but retransmits data to the far end 4916 * if necessary to fill gaps. 4917 */ 4918 struct sctp_chunk *abort = arg; 4919 4920 if (abort) 4921 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4922 4923 /* Even if we can't send the ABORT due to low memory delete the 4924 * TCB. This is a departure from our typical NOMEM handling. 4925 */ 4926 4927 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4928 SCTP_ERROR(ECONNABORTED)); 4929 /* Delete the established association. */ 4930 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4931 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4932 4933 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4934 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4935 4936 return SCTP_DISPOSITION_ABORT; 4937 } 4938 4939 /* We tried an illegal operation on an association which is closed. */ 4940 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4941 const struct sctp_endpoint *ep, 4942 const struct sctp_association *asoc, 4943 const sctp_subtype_t type, 4944 void *arg, 4945 sctp_cmd_seq_t *commands) 4946 { 4947 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4948 return SCTP_DISPOSITION_CONSUME; 4949 } 4950 4951 /* We tried an illegal operation on an association which is shutting 4952 * down. 4953 */ 4954 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4955 const struct sctp_endpoint *ep, 4956 const struct sctp_association *asoc, 4957 const sctp_subtype_t type, 4958 void *arg, 4959 sctp_cmd_seq_t *commands) 4960 { 4961 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4962 SCTP_ERROR(-ESHUTDOWN)); 4963 return SCTP_DISPOSITION_CONSUME; 4964 } 4965 4966 /* 4967 * sctp_cookie_wait_prm_shutdown 4968 * 4969 * Section: 4 Note: 2 4970 * Verification Tag: 4971 * Inputs 4972 * (endpoint, asoc) 4973 * 4974 * The RFC does not explicitly address this issue, but is the route through the 4975 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4976 * 4977 * Outputs 4978 * (timers) 4979 */ 4980 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4981 struct net *net, 4982 const struct sctp_endpoint *ep, 4983 const struct sctp_association *asoc, 4984 const sctp_subtype_t type, 4985 void *arg, 4986 sctp_cmd_seq_t *commands) 4987 { 4988 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4989 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4990 4991 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4992 SCTP_STATE(SCTP_STATE_CLOSED)); 4993 4994 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4995 4996 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4997 4998 return SCTP_DISPOSITION_DELETE_TCB; 4999 } 5000 5001 /* 5002 * sctp_cookie_echoed_prm_shutdown 5003 * 5004 * Section: 4 Note: 2 5005 * Verification Tag: 5006 * Inputs 5007 * (endpoint, asoc) 5008 * 5009 * The RFC does not explcitly address this issue, but is the route through the 5010 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5011 * 5012 * Outputs 5013 * (timers) 5014 */ 5015 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 5016 struct net *net, 5017 const struct sctp_endpoint *ep, 5018 const struct sctp_association *asoc, 5019 const sctp_subtype_t type, 5020 void *arg, sctp_cmd_seq_t *commands) 5021 { 5022 /* There is a single T1 timer, so we should be able to use 5023 * common function with the COOKIE-WAIT state. 5024 */ 5025 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5026 } 5027 5028 /* 5029 * sctp_sf_cookie_wait_prm_abort 5030 * 5031 * Section: 4 Note: 2 5032 * Verification Tag: 5033 * Inputs 5034 * (endpoint, asoc) 5035 * 5036 * The RFC does not explicitly address this issue, but is the route through the 5037 * state table when someone issues an abort while in COOKIE_WAIT state. 5038 * 5039 * Outputs 5040 * (timers) 5041 */ 5042 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 5043 struct net *net, 5044 const struct sctp_endpoint *ep, 5045 const struct sctp_association *asoc, 5046 const sctp_subtype_t type, 5047 void *arg, 5048 sctp_cmd_seq_t *commands) 5049 { 5050 struct sctp_chunk *abort = arg; 5051 5052 /* Stop T1-init timer */ 5053 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5054 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5055 5056 if (abort) 5057 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5058 5059 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5060 SCTP_STATE(SCTP_STATE_CLOSED)); 5061 5062 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5063 5064 /* Even if we can't send the ABORT due to low memory delete the 5065 * TCB. This is a departure from our typical NOMEM handling. 5066 */ 5067 5068 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5069 SCTP_ERROR(ECONNREFUSED)); 5070 /* Delete the established association. */ 5071 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5072 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5073 5074 return SCTP_DISPOSITION_ABORT; 5075 } 5076 5077 /* 5078 * sctp_sf_cookie_echoed_prm_abort 5079 * 5080 * Section: 4 Note: 3 5081 * Verification Tag: 5082 * Inputs 5083 * (endpoint, asoc) 5084 * 5085 * The RFC does not explcitly address this issue, but is the route through the 5086 * state table when someone issues an abort while in COOKIE_ECHOED state. 5087 * 5088 * Outputs 5089 * (timers) 5090 */ 5091 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 5092 struct net *net, 5093 const struct sctp_endpoint *ep, 5094 const struct sctp_association *asoc, 5095 const sctp_subtype_t type, 5096 void *arg, 5097 sctp_cmd_seq_t *commands) 5098 { 5099 /* There is a single T1 timer, so we should be able to use 5100 * common function with the COOKIE-WAIT state. 5101 */ 5102 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5103 } 5104 5105 /* 5106 * sctp_sf_shutdown_pending_prm_abort 5107 * 5108 * Inputs 5109 * (endpoint, asoc) 5110 * 5111 * The RFC does not explicitly address this issue, but is the route through the 5112 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5113 * 5114 * Outputs 5115 * (timers) 5116 */ 5117 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5118 struct net *net, 5119 const struct sctp_endpoint *ep, 5120 const struct sctp_association *asoc, 5121 const sctp_subtype_t type, 5122 void *arg, 5123 sctp_cmd_seq_t *commands) 5124 { 5125 /* Stop the T5-shutdown guard timer. */ 5126 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5127 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5128 5129 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5130 } 5131 5132 /* 5133 * sctp_sf_shutdown_sent_prm_abort 5134 * 5135 * Inputs 5136 * (endpoint, asoc) 5137 * 5138 * The RFC does not explicitly address this issue, but is the route through the 5139 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5140 * 5141 * Outputs 5142 * (timers) 5143 */ 5144 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5145 struct net *net, 5146 const struct sctp_endpoint *ep, 5147 const struct sctp_association *asoc, 5148 const sctp_subtype_t type, 5149 void *arg, 5150 sctp_cmd_seq_t *commands) 5151 { 5152 /* Stop the T2-shutdown timer. */ 5153 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5154 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5155 5156 /* Stop the T5-shutdown guard timer. */ 5157 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5158 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5159 5160 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5161 } 5162 5163 /* 5164 * sctp_sf_cookie_echoed_prm_abort 5165 * 5166 * Inputs 5167 * (endpoint, asoc) 5168 * 5169 * The RFC does not explcitly address this issue, but is the route through the 5170 * state table when someone issues an abort while in COOKIE_ECHOED state. 5171 * 5172 * Outputs 5173 * (timers) 5174 */ 5175 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5176 struct net *net, 5177 const struct sctp_endpoint *ep, 5178 const struct sctp_association *asoc, 5179 const sctp_subtype_t type, 5180 void *arg, 5181 sctp_cmd_seq_t *commands) 5182 { 5183 /* The same T2 timer, so we should be able to use 5184 * common function with the SHUTDOWN-SENT state. 5185 */ 5186 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5187 } 5188 5189 /* 5190 * Process the REQUESTHEARTBEAT primitive 5191 * 5192 * 10.1 ULP-to-SCTP 5193 * J) Request Heartbeat 5194 * 5195 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5196 * 5197 * -> result 5198 * 5199 * Instructs the local endpoint to perform a HeartBeat on the specified 5200 * destination transport address of the given association. The returned 5201 * result should indicate whether the transmission of the HEARTBEAT 5202 * chunk to the destination address is successful. 5203 * 5204 * Mandatory attributes: 5205 * 5206 * o association id - local handle to the SCTP association 5207 * 5208 * o destination transport address - the transport address of the 5209 * association on which a heartbeat should be issued. 5210 */ 5211 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5212 struct net *net, 5213 const struct sctp_endpoint *ep, 5214 const struct sctp_association *asoc, 5215 const sctp_subtype_t type, 5216 void *arg, 5217 sctp_cmd_seq_t *commands) 5218 { 5219 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5220 (struct sctp_transport *)arg, commands)) 5221 return SCTP_DISPOSITION_NOMEM; 5222 5223 /* 5224 * RFC 2960 (bis), section 8.3 5225 * 5226 * D) Request an on-demand HEARTBEAT on a specific destination 5227 * transport address of a given association. 5228 * 5229 * The endpoint should increment the respective error counter of 5230 * the destination transport address each time a HEARTBEAT is sent 5231 * to that address and not acknowledged within one RTO. 5232 * 5233 */ 5234 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5235 SCTP_TRANSPORT(arg)); 5236 return SCTP_DISPOSITION_CONSUME; 5237 } 5238 5239 /* 5240 * ADDIP Section 4.1 ASCONF Chunk Procedures 5241 * When an endpoint has an ASCONF signaled change to be sent to the 5242 * remote endpoint it should do A1 to A9 5243 */ 5244 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5245 const struct sctp_endpoint *ep, 5246 const struct sctp_association *asoc, 5247 const sctp_subtype_t type, 5248 void *arg, 5249 sctp_cmd_seq_t *commands) 5250 { 5251 struct sctp_chunk *chunk = arg; 5252 5253 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5254 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5255 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5256 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5257 return SCTP_DISPOSITION_CONSUME; 5258 } 5259 5260 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5261 sctp_disposition_t sctp_sf_do_prm_reconf(struct net *net, 5262 const struct sctp_endpoint *ep, 5263 const struct sctp_association *asoc, 5264 const sctp_subtype_t type, 5265 void *arg, sctp_cmd_seq_t *commands) 5266 { 5267 struct sctp_chunk *chunk = arg; 5268 5269 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5270 return SCTP_DISPOSITION_CONSUME; 5271 } 5272 5273 /* 5274 * Ignore the primitive event 5275 * 5276 * The return value is the disposition of the primitive. 5277 */ 5278 sctp_disposition_t sctp_sf_ignore_primitive( 5279 struct net *net, 5280 const struct sctp_endpoint *ep, 5281 const struct sctp_association *asoc, 5282 const sctp_subtype_t type, 5283 void *arg, 5284 sctp_cmd_seq_t *commands) 5285 { 5286 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5287 type.primitive); 5288 5289 return SCTP_DISPOSITION_DISCARD; 5290 } 5291 5292 /*************************************************************************** 5293 * These are the state functions for the OTHER events. 5294 ***************************************************************************/ 5295 5296 /* 5297 * When the SCTP stack has no more user data to send or retransmit, this 5298 * notification is given to the user. Also, at the time when a user app 5299 * subscribes to this event, if there is no data to be sent or 5300 * retransmit, the stack will immediately send up this notification. 5301 */ 5302 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5303 struct net *net, 5304 const struct sctp_endpoint *ep, 5305 const struct sctp_association *asoc, 5306 const sctp_subtype_t type, 5307 void *arg, 5308 sctp_cmd_seq_t *commands) 5309 { 5310 struct sctp_ulpevent *event; 5311 5312 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5313 if (!event) 5314 return SCTP_DISPOSITION_NOMEM; 5315 5316 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5317 5318 return SCTP_DISPOSITION_CONSUME; 5319 } 5320 5321 /* 5322 * Start the shutdown negotiation. 5323 * 5324 * From Section 9.2: 5325 * Once all its outstanding data has been acknowledged, the endpoint 5326 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5327 * TSN Ack field the last sequential TSN it has received from the peer. 5328 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5329 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5330 * with the updated last sequential TSN received from its peer. 5331 * 5332 * The return value is the disposition. 5333 */ 5334 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5335 struct net *net, 5336 const struct sctp_endpoint *ep, 5337 const struct sctp_association *asoc, 5338 const sctp_subtype_t type, 5339 void *arg, 5340 sctp_cmd_seq_t *commands) 5341 { 5342 struct sctp_chunk *reply; 5343 5344 /* Once all its outstanding data has been acknowledged, the 5345 * endpoint shall send a SHUTDOWN chunk to its peer including 5346 * in the Cumulative TSN Ack field the last sequential TSN it 5347 * has received from the peer. 5348 */ 5349 reply = sctp_make_shutdown(asoc, NULL); 5350 if (!reply) 5351 goto nomem; 5352 5353 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5354 * T2-shutdown timer. 5355 */ 5356 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5357 5358 /* It shall then start the T2-shutdown timer */ 5359 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5360 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5361 5362 /* RFC 4960 Section 9.2 5363 * The sender of the SHUTDOWN MAY also start an overall guard timer 5364 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5365 */ 5366 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5367 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5368 5369 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5370 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5371 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5372 5373 /* and enter the SHUTDOWN-SENT state. */ 5374 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5375 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5376 5377 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5378 * 5379 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5380 * or SHUTDOWN-ACK. 5381 */ 5382 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5383 5384 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5385 5386 return SCTP_DISPOSITION_CONSUME; 5387 5388 nomem: 5389 return SCTP_DISPOSITION_NOMEM; 5390 } 5391 5392 /* 5393 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5394 * 5395 * From Section 9.2: 5396 * 5397 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5398 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5399 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5400 * endpoint must re-send the SHUTDOWN ACK. 5401 * 5402 * The return value is the disposition. 5403 */ 5404 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5405 struct net *net, 5406 const struct sctp_endpoint *ep, 5407 const struct sctp_association *asoc, 5408 const sctp_subtype_t type, 5409 void *arg, 5410 sctp_cmd_seq_t *commands) 5411 { 5412 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5413 struct sctp_chunk *reply; 5414 5415 /* There are 2 ways of getting here: 5416 * 1) called in response to a SHUTDOWN chunk 5417 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5418 * 5419 * For the case (2), the arg parameter is set to NULL. We need 5420 * to check that we have a chunk before accessing it's fields. 5421 */ 5422 if (chunk) { 5423 if (!sctp_vtag_verify(chunk, asoc)) 5424 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5425 5426 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5427 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5428 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5429 commands); 5430 } 5431 5432 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5433 * shall send a SHUTDOWN ACK ... 5434 */ 5435 reply = sctp_make_shutdown_ack(asoc, chunk); 5436 if (!reply) 5437 goto nomem; 5438 5439 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5440 * the T2-shutdown timer. 5441 */ 5442 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5443 5444 /* and start/restart a T2-shutdown timer of its own, */ 5445 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5446 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5447 5448 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5449 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5450 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5451 5452 /* Enter the SHUTDOWN-ACK-SENT state. */ 5453 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5454 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5455 5456 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5457 * 5458 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5459 * or SHUTDOWN-ACK. 5460 */ 5461 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5462 5463 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5464 5465 return SCTP_DISPOSITION_CONSUME; 5466 5467 nomem: 5468 return SCTP_DISPOSITION_NOMEM; 5469 } 5470 5471 /* 5472 * Ignore the event defined as other 5473 * 5474 * The return value is the disposition of the event. 5475 */ 5476 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5477 const struct sctp_endpoint *ep, 5478 const struct sctp_association *asoc, 5479 const sctp_subtype_t type, 5480 void *arg, 5481 sctp_cmd_seq_t *commands) 5482 { 5483 pr_debug("%s: the event other type:%d is ignored\n", 5484 __func__, type.other); 5485 5486 return SCTP_DISPOSITION_DISCARD; 5487 } 5488 5489 /************************************************************ 5490 * These are the state functions for handling timeout events. 5491 ************************************************************/ 5492 5493 /* 5494 * RTX Timeout 5495 * 5496 * Section: 6.3.3 Handle T3-rtx Expiration 5497 * 5498 * Whenever the retransmission timer T3-rtx expires for a destination 5499 * address, do the following: 5500 * [See below] 5501 * 5502 * The return value is the disposition of the chunk. 5503 */ 5504 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5505 const struct sctp_endpoint *ep, 5506 const struct sctp_association *asoc, 5507 const sctp_subtype_t type, 5508 void *arg, 5509 sctp_cmd_seq_t *commands) 5510 { 5511 struct sctp_transport *transport = arg; 5512 5513 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5514 5515 if (asoc->overall_error_count >= asoc->max_retrans) { 5516 if (asoc->peer.zero_window_announced && 5517 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5518 /* 5519 * We are here likely because the receiver had its rwnd 5520 * closed for a while and we have not been able to 5521 * transmit the locally queued data within the maximum 5522 * retransmission attempts limit. Start the T5 5523 * shutdown guard timer to give the receiver one last 5524 * chance and some additional time to recover before 5525 * aborting. 5526 */ 5527 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5528 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5529 } else { 5530 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5531 SCTP_ERROR(ETIMEDOUT)); 5532 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5533 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5534 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5535 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5536 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5537 return SCTP_DISPOSITION_DELETE_TCB; 5538 } 5539 } 5540 5541 /* E1) For the destination address for which the timer 5542 * expires, adjust its ssthresh with rules defined in Section 5543 * 7.2.3 and set the cwnd <- MTU. 5544 */ 5545 5546 /* E2) For the destination address for which the timer 5547 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5548 * maximum value discussed in rule C7 above (RTO.max) may be 5549 * used to provide an upper bound to this doubling operation. 5550 */ 5551 5552 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5553 * outstanding DATA chunks for the address for which the 5554 * T3-rtx has expired will fit into a single packet, subject 5555 * to the MTU constraint for the path corresponding to the 5556 * destination transport address to which the retransmission 5557 * is being sent (this may be different from the address for 5558 * which the timer expires [see Section 6.4]). Call this 5559 * value K. Bundle and retransmit those K DATA chunks in a 5560 * single packet to the destination endpoint. 5561 * 5562 * Note: Any DATA chunks that were sent to the address for 5563 * which the T3-rtx timer expired but did not fit in one MTU 5564 * (rule E3 above), should be marked for retransmission and 5565 * sent as soon as cwnd allows (normally when a SACK arrives). 5566 */ 5567 5568 /* Do some failure management (Section 8.2). */ 5569 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5570 5571 /* NB: Rules E4 and F1 are implicit in R1. */ 5572 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5573 5574 return SCTP_DISPOSITION_CONSUME; 5575 } 5576 5577 /* 5578 * Generate delayed SACK on timeout 5579 * 5580 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5581 * 5582 * The guidelines on delayed acknowledgement algorithm specified in 5583 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5584 * acknowledgement SHOULD be generated for at least every second packet 5585 * (not every second DATA chunk) received, and SHOULD be generated 5586 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5587 * some situations it may be beneficial for an SCTP transmitter to be 5588 * more conservative than the algorithms detailed in this document 5589 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5590 * the following algorithms allow. 5591 */ 5592 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5593 const struct sctp_endpoint *ep, 5594 const struct sctp_association *asoc, 5595 const sctp_subtype_t type, 5596 void *arg, 5597 sctp_cmd_seq_t *commands) 5598 { 5599 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5600 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5601 return SCTP_DISPOSITION_CONSUME; 5602 } 5603 5604 /* 5605 * sctp_sf_t1_init_timer_expire 5606 * 5607 * Section: 4 Note: 2 5608 * Verification Tag: 5609 * Inputs 5610 * (endpoint, asoc) 5611 * 5612 * RFC 2960 Section 4 Notes 5613 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5614 * and re-start the T1-init timer without changing state. This MUST 5615 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5616 * endpoint MUST abort the initialization process and report the 5617 * error to SCTP user. 5618 * 5619 * Outputs 5620 * (timers, events) 5621 * 5622 */ 5623 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5624 const struct sctp_endpoint *ep, 5625 const struct sctp_association *asoc, 5626 const sctp_subtype_t type, 5627 void *arg, 5628 sctp_cmd_seq_t *commands) 5629 { 5630 struct sctp_chunk *repl = NULL; 5631 struct sctp_bind_addr *bp; 5632 int attempts = asoc->init_err_counter + 1; 5633 5634 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5635 5636 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5637 5638 if (attempts <= asoc->max_init_attempts) { 5639 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5640 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5641 if (!repl) 5642 return SCTP_DISPOSITION_NOMEM; 5643 5644 /* Choose transport for INIT. */ 5645 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5646 SCTP_CHUNK(repl)); 5647 5648 /* Issue a sideeffect to do the needed accounting. */ 5649 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5650 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5651 5652 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5653 } else { 5654 pr_debug("%s: giving up on INIT, attempts:%d " 5655 "max_init_attempts:%d\n", __func__, attempts, 5656 asoc->max_init_attempts); 5657 5658 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5659 SCTP_ERROR(ETIMEDOUT)); 5660 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5661 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5662 return SCTP_DISPOSITION_DELETE_TCB; 5663 } 5664 5665 return SCTP_DISPOSITION_CONSUME; 5666 } 5667 5668 /* 5669 * sctp_sf_t1_cookie_timer_expire 5670 * 5671 * Section: 4 Note: 2 5672 * Verification Tag: 5673 * Inputs 5674 * (endpoint, asoc) 5675 * 5676 * RFC 2960 Section 4 Notes 5677 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5678 * COOKIE ECHO and re-start the T1-cookie timer without changing 5679 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5680 * After that, the endpoint MUST abort the initialization process and 5681 * report the error to SCTP user. 5682 * 5683 * Outputs 5684 * (timers, events) 5685 * 5686 */ 5687 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5688 const struct sctp_endpoint *ep, 5689 const struct sctp_association *asoc, 5690 const sctp_subtype_t type, 5691 void *arg, 5692 sctp_cmd_seq_t *commands) 5693 { 5694 struct sctp_chunk *repl = NULL; 5695 int attempts = asoc->init_err_counter + 1; 5696 5697 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5698 5699 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5700 5701 if (attempts <= asoc->max_init_attempts) { 5702 repl = sctp_make_cookie_echo(asoc, NULL); 5703 if (!repl) 5704 return SCTP_DISPOSITION_NOMEM; 5705 5706 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5707 SCTP_CHUNK(repl)); 5708 /* Issue a sideeffect to do the needed accounting. */ 5709 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5710 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5711 5712 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5713 } else { 5714 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5715 SCTP_ERROR(ETIMEDOUT)); 5716 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5717 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5718 return SCTP_DISPOSITION_DELETE_TCB; 5719 } 5720 5721 return SCTP_DISPOSITION_CONSUME; 5722 } 5723 5724 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5725 * with the updated last sequential TSN received from its peer. 5726 * 5727 * An endpoint should limit the number of retransmissions of the 5728 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5729 * If this threshold is exceeded the endpoint should destroy the TCB and 5730 * MUST report the peer endpoint unreachable to the upper layer (and 5731 * thus the association enters the CLOSED state). The reception of any 5732 * packet from its peer (i.e. as the peer sends all of its queued DATA 5733 * chunks) should clear the endpoint's retransmission count and restart 5734 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5735 * all of its queued DATA chunks that have not yet been sent. 5736 */ 5737 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5738 const struct sctp_endpoint *ep, 5739 const struct sctp_association *asoc, 5740 const sctp_subtype_t type, 5741 void *arg, 5742 sctp_cmd_seq_t *commands) 5743 { 5744 struct sctp_chunk *reply = NULL; 5745 5746 pr_debug("%s: timer T2 expired\n", __func__); 5747 5748 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5749 5750 ((struct sctp_association *)asoc)->shutdown_retries++; 5751 5752 if (asoc->overall_error_count >= asoc->max_retrans) { 5753 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5754 SCTP_ERROR(ETIMEDOUT)); 5755 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5756 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5757 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5758 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5759 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5760 return SCTP_DISPOSITION_DELETE_TCB; 5761 } 5762 5763 switch (asoc->state) { 5764 case SCTP_STATE_SHUTDOWN_SENT: 5765 reply = sctp_make_shutdown(asoc, NULL); 5766 break; 5767 5768 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5769 reply = sctp_make_shutdown_ack(asoc, NULL); 5770 break; 5771 5772 default: 5773 BUG(); 5774 break; 5775 } 5776 5777 if (!reply) 5778 goto nomem; 5779 5780 /* Do some failure management (Section 8.2). 5781 * If we remove the transport an SHUTDOWN was last sent to, don't 5782 * do failure management. 5783 */ 5784 if (asoc->shutdown_last_sent_to) 5785 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5786 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5787 5788 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5789 * the T2-shutdown timer. 5790 */ 5791 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5792 5793 /* Restart the T2-shutdown timer. */ 5794 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5795 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5796 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5797 return SCTP_DISPOSITION_CONSUME; 5798 5799 nomem: 5800 return SCTP_DISPOSITION_NOMEM; 5801 } 5802 5803 /* 5804 * ADDIP Section 4.1 ASCONF CHunk Procedures 5805 * If the T4 RTO timer expires the endpoint should do B1 to B5 5806 */ 5807 sctp_disposition_t sctp_sf_t4_timer_expire( 5808 struct net *net, 5809 const struct sctp_endpoint *ep, 5810 const struct sctp_association *asoc, 5811 const sctp_subtype_t type, 5812 void *arg, 5813 sctp_cmd_seq_t *commands) 5814 { 5815 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5816 struct sctp_transport *transport = chunk->transport; 5817 5818 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5819 5820 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5821 * detection on the appropriate destination address as defined in 5822 * RFC2960 [5] section 8.1 and 8.2. 5823 */ 5824 if (transport) 5825 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5826 SCTP_TRANSPORT(transport)); 5827 5828 /* Reconfig T4 timer and transport. */ 5829 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5830 5831 /* ADDIP 4.1 B2) Increment the association error counters and perform 5832 * endpoint failure detection on the association as defined in 5833 * RFC2960 [5] section 8.1 and 8.2. 5834 * association error counter is incremented in SCTP_CMD_STRIKE. 5835 */ 5836 if (asoc->overall_error_count >= asoc->max_retrans) { 5837 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5838 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5839 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5840 SCTP_ERROR(ETIMEDOUT)); 5841 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5842 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5843 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5844 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5845 return SCTP_DISPOSITION_ABORT; 5846 } 5847 5848 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5849 * the ASCONF chunk was sent by doubling the RTO timer value. 5850 * This is done in SCTP_CMD_STRIKE. 5851 */ 5852 5853 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5854 * choose an alternate destination address (please refer to RFC2960 5855 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5856 * chunk, it MUST be the same (including its serial number) as the last 5857 * ASCONF sent. 5858 */ 5859 sctp_chunk_hold(asoc->addip_last_asconf); 5860 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5861 SCTP_CHUNK(asoc->addip_last_asconf)); 5862 5863 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5864 * destination is selected, then the RTO used will be that of the new 5865 * destination address. 5866 */ 5867 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5868 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5869 5870 return SCTP_DISPOSITION_CONSUME; 5871 } 5872 5873 /* sctpimpguide-05 Section 2.12.2 5874 * The sender of the SHUTDOWN MAY also start an overall guard timer 5875 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5876 * At the expiration of this timer the sender SHOULD abort the association 5877 * by sending an ABORT chunk. 5878 */ 5879 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5880 const struct sctp_endpoint *ep, 5881 const struct sctp_association *asoc, 5882 const sctp_subtype_t type, 5883 void *arg, 5884 sctp_cmd_seq_t *commands) 5885 { 5886 struct sctp_chunk *reply = NULL; 5887 5888 pr_debug("%s: timer T5 expired\n", __func__); 5889 5890 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5891 5892 reply = sctp_make_abort(asoc, NULL, 0); 5893 if (!reply) 5894 goto nomem; 5895 5896 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5897 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5898 SCTP_ERROR(ETIMEDOUT)); 5899 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5900 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5901 5902 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5903 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5904 5905 return SCTP_DISPOSITION_DELETE_TCB; 5906 nomem: 5907 return SCTP_DISPOSITION_NOMEM; 5908 } 5909 5910 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5911 * the association is automatically closed by starting the shutdown process. 5912 * The work that needs to be done is same as when SHUTDOWN is initiated by 5913 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5914 */ 5915 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5916 struct net *net, 5917 const struct sctp_endpoint *ep, 5918 const struct sctp_association *asoc, 5919 const sctp_subtype_t type, 5920 void *arg, 5921 sctp_cmd_seq_t *commands) 5922 { 5923 int disposition; 5924 5925 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5926 5927 /* From 9.2 Shutdown of an Association 5928 * Upon receipt of the SHUTDOWN primitive from its upper 5929 * layer, the endpoint enters SHUTDOWN-PENDING state and 5930 * remains there until all outstanding data has been 5931 * acknowledged by its peer. The endpoint accepts no new data 5932 * from its upper layer, but retransmits data to the far end 5933 * if necessary to fill gaps. 5934 */ 5935 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5936 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5937 5938 disposition = SCTP_DISPOSITION_CONSUME; 5939 if (sctp_outq_is_empty(&asoc->outqueue)) { 5940 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5941 arg, commands); 5942 } 5943 return disposition; 5944 } 5945 5946 /***************************************************************************** 5947 * These are sa state functions which could apply to all types of events. 5948 ****************************************************************************/ 5949 5950 /* 5951 * This table entry is not implemented. 5952 * 5953 * Inputs 5954 * (endpoint, asoc, chunk) 5955 * 5956 * The return value is the disposition of the chunk. 5957 */ 5958 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5959 const struct sctp_endpoint *ep, 5960 const struct sctp_association *asoc, 5961 const sctp_subtype_t type, 5962 void *arg, 5963 sctp_cmd_seq_t *commands) 5964 { 5965 return SCTP_DISPOSITION_NOT_IMPL; 5966 } 5967 5968 /* 5969 * This table entry represents a bug. 5970 * 5971 * Inputs 5972 * (endpoint, asoc, chunk) 5973 * 5974 * The return value is the disposition of the chunk. 5975 */ 5976 sctp_disposition_t sctp_sf_bug(struct net *net, 5977 const struct sctp_endpoint *ep, 5978 const struct sctp_association *asoc, 5979 const sctp_subtype_t type, 5980 void *arg, 5981 sctp_cmd_seq_t *commands) 5982 { 5983 return SCTP_DISPOSITION_BUG; 5984 } 5985 5986 /* 5987 * This table entry represents the firing of a timer in the wrong state. 5988 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5989 * when the association is in the wrong state. This event should 5990 * be ignored, so as to prevent any rearming of the timer. 5991 * 5992 * Inputs 5993 * (endpoint, asoc, chunk) 5994 * 5995 * The return value is the disposition of the chunk. 5996 */ 5997 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5998 const struct sctp_endpoint *ep, 5999 const struct sctp_association *asoc, 6000 const sctp_subtype_t type, 6001 void *arg, 6002 sctp_cmd_seq_t *commands) 6003 { 6004 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6005 6006 return SCTP_DISPOSITION_CONSUME; 6007 } 6008 6009 /******************************************************************** 6010 * 2nd Level Abstractions 6011 ********************************************************************/ 6012 6013 /* Pull the SACK chunk based on the SACK header. */ 6014 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6015 { 6016 struct sctp_sackhdr *sack; 6017 unsigned int len; 6018 __u16 num_blocks; 6019 __u16 num_dup_tsns; 6020 6021 /* Protect ourselves from reading too far into 6022 * the skb from a bogus sender. 6023 */ 6024 sack = (struct sctp_sackhdr *) chunk->skb->data; 6025 6026 num_blocks = ntohs(sack->num_gap_ack_blocks); 6027 num_dup_tsns = ntohs(sack->num_dup_tsns); 6028 len = sizeof(struct sctp_sackhdr); 6029 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6030 if (len > chunk->skb->len) 6031 return NULL; 6032 6033 skb_pull(chunk->skb, len); 6034 6035 return sack; 6036 } 6037 6038 /* Create an ABORT packet to be sent as a response, with the specified 6039 * error causes. 6040 */ 6041 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 6042 const struct sctp_endpoint *ep, 6043 const struct sctp_association *asoc, 6044 struct sctp_chunk *chunk, 6045 const void *payload, 6046 size_t paylen) 6047 { 6048 struct sctp_packet *packet; 6049 struct sctp_chunk *abort; 6050 6051 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6052 6053 if (packet) { 6054 /* Make an ABORT. 6055 * The T bit will be set if the asoc is NULL. 6056 */ 6057 abort = sctp_make_abort(asoc, chunk, paylen); 6058 if (!abort) { 6059 sctp_ootb_pkt_free(packet); 6060 return NULL; 6061 } 6062 6063 /* Reflect vtag if T-Bit is set */ 6064 if (sctp_test_T_bit(abort)) 6065 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6066 6067 /* Add specified error causes, i.e., payload, to the 6068 * end of the chunk. 6069 */ 6070 sctp_addto_chunk(abort, paylen, payload); 6071 6072 /* Set the skb to the belonging sock for accounting. */ 6073 abort->skb->sk = ep->base.sk; 6074 6075 sctp_packet_append_chunk(packet, abort); 6076 6077 } 6078 6079 return packet; 6080 } 6081 6082 /* Allocate a packet for responding in the OOTB conditions. */ 6083 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 6084 const struct sctp_association *asoc, 6085 const struct sctp_chunk *chunk) 6086 { 6087 struct sctp_packet *packet; 6088 struct sctp_transport *transport; 6089 __u16 sport; 6090 __u16 dport; 6091 __u32 vtag; 6092 6093 /* Get the source and destination port from the inbound packet. */ 6094 sport = ntohs(chunk->sctp_hdr->dest); 6095 dport = ntohs(chunk->sctp_hdr->source); 6096 6097 /* The V-tag is going to be the same as the inbound packet if no 6098 * association exists, otherwise, use the peer's vtag. 6099 */ 6100 if (asoc) { 6101 /* Special case the INIT-ACK as there is no peer's vtag 6102 * yet. 6103 */ 6104 switch (chunk->chunk_hdr->type) { 6105 case SCTP_CID_INIT_ACK: 6106 { 6107 sctp_initack_chunk_t *initack; 6108 6109 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6110 vtag = ntohl(initack->init_hdr.init_tag); 6111 break; 6112 } 6113 default: 6114 vtag = asoc->peer.i.init_tag; 6115 break; 6116 } 6117 } else { 6118 /* Special case the INIT and stale COOKIE_ECHO as there is no 6119 * vtag yet. 6120 */ 6121 switch (chunk->chunk_hdr->type) { 6122 case SCTP_CID_INIT: 6123 { 6124 sctp_init_chunk_t *init; 6125 6126 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6127 vtag = ntohl(init->init_hdr.init_tag); 6128 break; 6129 } 6130 default: 6131 vtag = ntohl(chunk->sctp_hdr->vtag); 6132 break; 6133 } 6134 } 6135 6136 /* Make a transport for the bucket, Eliza... */ 6137 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6138 if (!transport) 6139 goto nomem; 6140 6141 /* Cache a route for the transport with the chunk's destination as 6142 * the source address. 6143 */ 6144 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6145 sctp_sk(net->sctp.ctl_sock)); 6146 6147 packet = &transport->packet; 6148 sctp_packet_init(packet, transport, sport, dport); 6149 sctp_packet_config(packet, vtag, 0); 6150 6151 return packet; 6152 6153 nomem: 6154 return NULL; 6155 } 6156 6157 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6158 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6159 { 6160 sctp_transport_free(packet->transport); 6161 } 6162 6163 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6164 static void sctp_send_stale_cookie_err(struct net *net, 6165 const struct sctp_endpoint *ep, 6166 const struct sctp_association *asoc, 6167 const struct sctp_chunk *chunk, 6168 sctp_cmd_seq_t *commands, 6169 struct sctp_chunk *err_chunk) 6170 { 6171 struct sctp_packet *packet; 6172 6173 if (err_chunk) { 6174 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6175 if (packet) { 6176 struct sctp_signed_cookie *cookie; 6177 6178 /* Override the OOTB vtag from the cookie. */ 6179 cookie = chunk->subh.cookie_hdr; 6180 packet->vtag = cookie->c.peer_vtag; 6181 6182 /* Set the skb to the belonging sock for accounting. */ 6183 err_chunk->skb->sk = ep->base.sk; 6184 sctp_packet_append_chunk(packet, err_chunk); 6185 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6186 SCTP_PACKET(packet)); 6187 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6188 } else 6189 sctp_chunk_free (err_chunk); 6190 } 6191 } 6192 6193 6194 /* Process a data chunk */ 6195 static int sctp_eat_data(const struct sctp_association *asoc, 6196 struct sctp_chunk *chunk, 6197 sctp_cmd_seq_t *commands) 6198 { 6199 sctp_datahdr_t *data_hdr; 6200 struct sctp_chunk *err; 6201 size_t datalen; 6202 sctp_verb_t deliver; 6203 int tmp; 6204 __u32 tsn; 6205 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6206 struct sock *sk = asoc->base.sk; 6207 struct net *net = sock_net(sk); 6208 u16 ssn; 6209 u16 sid; 6210 u8 ordered = 0; 6211 6212 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6213 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6214 6215 tsn = ntohl(data_hdr->tsn); 6216 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6217 6218 /* ASSERT: Now skb->data is really the user data. */ 6219 6220 /* Process ECN based congestion. 6221 * 6222 * Since the chunk structure is reused for all chunks within 6223 * a packet, we use ecn_ce_done to track if we've already 6224 * done CE processing for this packet. 6225 * 6226 * We need to do ECN processing even if we plan to discard the 6227 * chunk later. 6228 */ 6229 6230 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6231 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6232 chunk->ecn_ce_done = 1; 6233 6234 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6235 /* Do real work as sideffect. */ 6236 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6237 SCTP_U32(tsn)); 6238 } 6239 } 6240 6241 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6242 if (tmp < 0) { 6243 /* The TSN is too high--silently discard the chunk and 6244 * count on it getting retransmitted later. 6245 */ 6246 if (chunk->asoc) 6247 chunk->asoc->stats.outofseqtsns++; 6248 return SCTP_IERROR_HIGH_TSN; 6249 } else if (tmp > 0) { 6250 /* This is a duplicate. Record it. */ 6251 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6252 return SCTP_IERROR_DUP_TSN; 6253 } 6254 6255 /* This is a new TSN. */ 6256 6257 /* Discard if there is no room in the receive window. 6258 * Actually, allow a little bit of overflow (up to a MTU). 6259 */ 6260 datalen = ntohs(chunk->chunk_hdr->length); 6261 datalen -= sizeof(sctp_data_chunk_t); 6262 6263 deliver = SCTP_CMD_CHUNK_ULP; 6264 6265 /* Think about partial delivery. */ 6266 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6267 6268 /* Even if we don't accept this chunk there is 6269 * memory pressure. 6270 */ 6271 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6272 } 6273 6274 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6275 * seems a bit troublesome in that frag_point varies based on 6276 * PMTU. In cases, such as loopback, this might be a rather 6277 * large spill over. 6278 */ 6279 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6280 (datalen > asoc->rwnd + asoc->frag_point))) { 6281 6282 /* If this is the next TSN, consider reneging to make 6283 * room. Note: Playing nice with a confused sender. A 6284 * malicious sender can still eat up all our buffer 6285 * space and in the future we may want to detect and 6286 * do more drastic reneging. 6287 */ 6288 if (sctp_tsnmap_has_gap(map) && 6289 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6290 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6291 deliver = SCTP_CMD_RENEGE; 6292 } else { 6293 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6294 __func__, tsn, datalen, asoc->rwnd); 6295 6296 return SCTP_IERROR_IGNORE_TSN; 6297 } 6298 } 6299 6300 /* 6301 * Also try to renege to limit our memory usage in the event that 6302 * we are under memory pressure 6303 * If we can't renege, don't worry about it, the sk_rmem_schedule 6304 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6305 * memory usage too much 6306 */ 6307 if (*sk->sk_prot_creator->memory_pressure) { 6308 if (sctp_tsnmap_has_gap(map) && 6309 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6310 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6311 __func__, tsn); 6312 deliver = SCTP_CMD_RENEGE; 6313 } 6314 } 6315 6316 /* 6317 * Section 3.3.10.9 No User Data (9) 6318 * 6319 * Cause of error 6320 * --------------- 6321 * No User Data: This error cause is returned to the originator of a 6322 * DATA chunk if a received DATA chunk has no user data. 6323 */ 6324 if (unlikely(0 == datalen)) { 6325 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6326 if (err) { 6327 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6328 SCTP_CHUNK(err)); 6329 } 6330 /* We are going to ABORT, so we might as well stop 6331 * processing the rest of the chunks in the packet. 6332 */ 6333 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6334 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6335 SCTP_ERROR(ECONNABORTED)); 6336 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6337 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6338 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6339 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6340 return SCTP_IERROR_NO_DATA; 6341 } 6342 6343 chunk->data_accepted = 1; 6344 6345 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6346 * if we renege and the chunk arrives again. 6347 */ 6348 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6349 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6350 if (chunk->asoc) 6351 chunk->asoc->stats.iuodchunks++; 6352 } else { 6353 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6354 if (chunk->asoc) 6355 chunk->asoc->stats.iodchunks++; 6356 ordered = 1; 6357 } 6358 6359 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6360 * 6361 * If an endpoint receive a DATA chunk with an invalid stream 6362 * identifier, it shall acknowledge the reception of the DATA chunk 6363 * following the normal procedure, immediately send an ERROR chunk 6364 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6365 * and discard the DATA chunk. 6366 */ 6367 sid = ntohs(data_hdr->stream); 6368 if (sid >= asoc->stream->incnt) { 6369 /* Mark tsn as received even though we drop it */ 6370 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6371 6372 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6373 &data_hdr->stream, 6374 sizeof(data_hdr->stream), 6375 sizeof(u16)); 6376 if (err) 6377 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6378 SCTP_CHUNK(err)); 6379 return SCTP_IERROR_BAD_STREAM; 6380 } 6381 6382 /* Check to see if the SSN is possible for this TSN. 6383 * The biggest gap we can record is 4K wide. Since SSNs wrap 6384 * at an unsigned short, there is no way that an SSN can 6385 * wrap and for a valid TSN. We can simply check if the current 6386 * SSN is smaller then the next expected one. If it is, it wrapped 6387 * and is invalid. 6388 */ 6389 ssn = ntohs(data_hdr->ssn); 6390 if (ordered && SSN_lt(ssn, sctp_ssn_peek(asoc->stream, in, sid))) 6391 return SCTP_IERROR_PROTO_VIOLATION; 6392 6393 /* Send the data up to the user. Note: Schedule the 6394 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6395 * chunk needs the updated rwnd. 6396 */ 6397 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6398 6399 return SCTP_IERROR_NO_ERROR; 6400 } 6401