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( 63 struct net *net, 64 const struct sctp_endpoint *ep, 65 const struct sctp_association *asoc, 66 struct sctp_chunk *chunk, 67 const void *payload, size_t paylen); 68 static int sctp_eat_data(const struct sctp_association *asoc, 69 struct sctp_chunk *chunk, 70 struct sctp_cmd_seq *commands); 71 static struct sctp_packet *sctp_ootb_pkt_new( 72 struct net *net, 73 const struct sctp_association *asoc, 74 const struct sctp_chunk *chunk); 75 static void sctp_send_stale_cookie_err(struct net *net, 76 const struct sctp_endpoint *ep, 77 const struct sctp_association *asoc, 78 const struct sctp_chunk *chunk, 79 struct sctp_cmd_seq *commands, 80 struct sctp_chunk *err_chunk); 81 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 82 struct net *net, 83 const struct sctp_endpoint *ep, 84 const struct sctp_association *asoc, 85 const union sctp_subtype type, 86 void *arg, 87 struct sctp_cmd_seq *commands); 88 static enum sctp_disposition sctp_sf_shut_8_4_5( 89 struct net *net, 90 const struct sctp_endpoint *ep, 91 const struct sctp_association *asoc, 92 const union sctp_subtype type, 93 void *arg, 94 struct sctp_cmd_seq *commands); 95 static enum sctp_disposition sctp_sf_tabort_8_4_8( 96 struct net *net, 97 const struct sctp_endpoint *ep, 98 const struct sctp_association *asoc, 99 const union sctp_subtype type, 100 void *arg, 101 struct sctp_cmd_seq *commands); 102 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 103 104 static enum sctp_disposition sctp_stop_t1_and_abort( 105 struct net *net, 106 struct sctp_cmd_seq *commands, 107 __be16 error, int sk_err, 108 const struct sctp_association *asoc, 109 struct sctp_transport *transport); 110 111 static enum sctp_disposition sctp_sf_abort_violation( 112 struct net *net, 113 const struct sctp_endpoint *ep, 114 const struct sctp_association *asoc, 115 void *arg, 116 struct sctp_cmd_seq *commands, 117 const __u8 *payload, 118 const size_t paylen); 119 120 static enum sctp_disposition sctp_sf_violation_chunklen( 121 struct net *net, 122 const struct sctp_endpoint *ep, 123 const struct sctp_association *asoc, 124 const union sctp_subtype type, 125 void *arg, 126 struct sctp_cmd_seq *commands); 127 128 static enum sctp_disposition sctp_sf_violation_paramlen( 129 struct net *net, 130 const struct sctp_endpoint *ep, 131 const struct sctp_association *asoc, 132 const union sctp_subtype type, 133 void *arg, void *ext, 134 struct sctp_cmd_seq *commands); 135 136 static enum sctp_disposition sctp_sf_violation_ctsn( 137 struct net *net, 138 const struct sctp_endpoint *ep, 139 const struct sctp_association *asoc, 140 const union sctp_subtype type, 141 void *arg, 142 struct sctp_cmd_seq *commands); 143 144 static enum sctp_disposition sctp_sf_violation_chunk( 145 struct net *net, 146 const struct sctp_endpoint *ep, 147 const struct sctp_association *asoc, 148 const union sctp_subtype type, 149 void *arg, 150 struct sctp_cmd_seq *commands); 151 152 static enum sctp_ierror sctp_sf_authenticate( 153 struct net *net, 154 const struct sctp_endpoint *ep, 155 const struct sctp_association *asoc, 156 const union sctp_subtype type, 157 struct sctp_chunk *chunk); 158 159 static enum sctp_disposition __sctp_sf_do_9_1_abort( 160 struct net *net, 161 const struct sctp_endpoint *ep, 162 const struct sctp_association *asoc, 163 const union sctp_subtype type, 164 void *arg, 165 struct sctp_cmd_seq *commands); 166 167 /* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: true = Valid length 171 * false = Invalid length 172 * 173 */ 174 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 175 __u16 required_length) 176 { 177 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 178 179 /* Previously already marked? */ 180 if (unlikely(chunk->pdiscard)) 181 return false; 182 if (unlikely(chunk_length < required_length)) 183 return false; 184 185 return true; 186 } 187 188 /********************************************************** 189 * These are the state functions for handling chunk events. 190 **********************************************************/ 191 192 /* 193 * Process the final SHUTDOWN COMPLETE. 194 * 195 * Section: 4 (C) (diagram), 9.2 196 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 197 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 198 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 199 * should stop the T2-shutdown timer and remove all knowledge of the 200 * association (and thus the association enters the CLOSED state). 201 * 202 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 203 * C) Rules for packet carrying SHUTDOWN COMPLETE: 204 * ... 205 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 206 * if the Verification Tag field of the packet matches its own tag and 207 * the T bit is not set 208 * OR 209 * it is set to its peer's tag and the T bit is set in the Chunk 210 * Flags. 211 * Otherwise, the receiver MUST silently discard the packet 212 * and take no further action. An endpoint MUST ignore the 213 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 214 * 215 * Inputs 216 * (endpoint, asoc, chunk) 217 * 218 * Outputs 219 * (asoc, reply_msg, msg_up, timers, counters) 220 * 221 * The return value is the disposition of the chunk. 222 */ 223 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 224 const struct sctp_endpoint *ep, 225 const struct sctp_association *asoc, 226 const union sctp_subtype type, 227 void *arg, struct sctp_cmd_seq *commands) 228 { 229 struct sctp_chunk *chunk = arg; 230 struct sctp_ulpevent *ev; 231 232 if (!sctp_vtag_verify_either(chunk, asoc)) 233 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 234 235 /* RFC 2960 6.10 Bundling 236 * 237 * An endpoint MUST NOT bundle INIT, INIT ACK or 238 * SHUTDOWN COMPLETE with any other chunks. 239 */ 240 if (!chunk->singleton) 241 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 242 243 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 244 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 245 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 246 commands); 247 248 /* RFC 2960 10.2 SCTP-to-ULP 249 * 250 * H) SHUTDOWN COMPLETE notification 251 * 252 * When SCTP completes the shutdown procedures (section 9.2) this 253 * notification is passed to the upper layer. 254 */ 255 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 256 0, 0, 0, NULL, GFP_ATOMIC); 257 if (ev) 258 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 259 SCTP_ULPEVENT(ev)); 260 261 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 262 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 263 * not the chunk should be discarded. If the endpoint is in 264 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 265 * T2-shutdown timer and remove all knowledge of the 266 * association (and thus the association enters the CLOSED 267 * state). 268 */ 269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 270 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 271 272 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 273 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 274 275 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 276 SCTP_STATE(SCTP_STATE_CLOSED)); 277 278 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 279 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 280 281 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 282 283 return SCTP_DISPOSITION_DELETE_TCB; 284 } 285 286 /* 287 * Respond to a normal INIT chunk. 288 * We are the side that is being asked for an association. 289 * 290 * Section: 5.1 Normal Establishment of an Association, B 291 * B) "Z" shall respond immediately with an INIT ACK chunk. The 292 * destination IP address of the INIT ACK MUST be set to the source 293 * IP address of the INIT to which this INIT ACK is responding. In 294 * the response, besides filling in other parameters, "Z" must set the 295 * Verification Tag field to Tag_A, and also provide its own 296 * Verification Tag (Tag_Z) in the Initiate Tag field. 297 * 298 * Verification Tag: Must be 0. 299 * 300 * Inputs 301 * (endpoint, asoc, chunk) 302 * 303 * Outputs 304 * (asoc, reply_msg, msg_up, timers, counters) 305 * 306 * The return value is the disposition of the chunk. 307 */ 308 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 309 const struct sctp_endpoint *ep, 310 const struct sctp_association *asoc, 311 const union sctp_subtype type, 312 void *arg, 313 struct sctp_cmd_seq *commands) 314 { 315 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 316 struct sctp_unrecognized_param *unk_param; 317 struct sctp_association *new_asoc; 318 struct sctp_packet *packet; 319 int len; 320 321 /* 6.10 Bundling 322 * An endpoint MUST NOT bundle INIT, INIT ACK or 323 * SHUTDOWN COMPLETE with any other chunks. 324 * 325 * IG Section 2.11.2 326 * Furthermore, we require that the receiver of an INIT chunk MUST 327 * enforce these rules by silently discarding an arriving packet 328 * with an INIT chunk that is bundled with other chunks. 329 */ 330 if (!chunk->singleton) 331 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 332 333 /* If the packet is an OOTB packet which is temporarily on the 334 * control endpoint, respond with an ABORT. 335 */ 336 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 337 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 338 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 339 } 340 341 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 342 * Tag. 343 */ 344 if (chunk->sctp_hdr->vtag != 0) 345 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 346 347 /* Make sure that the INIT chunk has a valid length. 348 * Normally, this would cause an ABORT with a Protocol Violation 349 * error, but since we don't have an association, we'll 350 * just discard the packet. 351 */ 352 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 353 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 354 355 /* If the INIT is coming toward a closing socket, we'll send back 356 * and ABORT. Essentially, this catches the race of INIT being 357 * backloged to the socket at the same time as the user isses close(). 358 * Since the socket and all its associations are going away, we 359 * can treat this OOTB 360 */ 361 if (sctp_sstate(ep->base.sk, CLOSING)) 362 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 363 364 /* Verify the INIT chunk before processing it. */ 365 err_chunk = NULL; 366 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 367 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 368 &err_chunk)) { 369 /* This chunk contains fatal error. It is to be discarded. 370 * Send an ABORT, with causes if there is any. 371 */ 372 if (err_chunk) { 373 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 374 (__u8 *)(err_chunk->chunk_hdr) + 375 sizeof(struct sctp_chunkhdr), 376 ntohs(err_chunk->chunk_hdr->length) - 377 sizeof(struct sctp_chunkhdr)); 378 379 sctp_chunk_free(err_chunk); 380 381 if (packet) { 382 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 383 SCTP_PACKET(packet)); 384 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 385 return SCTP_DISPOSITION_CONSUME; 386 } else { 387 return SCTP_DISPOSITION_NOMEM; 388 } 389 } else { 390 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 391 commands); 392 } 393 } 394 395 /* Grab the INIT header. */ 396 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 397 398 /* Tag the variable length parameters. */ 399 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 400 401 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 402 if (!new_asoc) 403 goto nomem; 404 405 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 406 sctp_scope(sctp_source(chunk)), 407 GFP_ATOMIC) < 0) 408 goto nomem_init; 409 410 /* The call, sctp_process_init(), can fail on memory allocation. */ 411 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 412 (struct sctp_init_chunk *)chunk->chunk_hdr, 413 GFP_ATOMIC)) 414 goto nomem_init; 415 416 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 417 418 /* If there are errors need to be reported for unknown parameters, 419 * make sure to reserve enough room in the INIT ACK for them. 420 */ 421 len = 0; 422 if (err_chunk) 423 len = ntohs(err_chunk->chunk_hdr->length) - 424 sizeof(struct sctp_chunkhdr); 425 426 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 427 if (!repl) 428 goto nomem_init; 429 430 /* If there are errors need to be reported for unknown parameters, 431 * include them in the outgoing INIT ACK as "Unrecognized parameter" 432 * parameter. 433 */ 434 if (err_chunk) { 435 /* Get the "Unrecognized parameter" parameter(s) out of the 436 * ERROR chunk generated by sctp_verify_init(). Since the 437 * error cause code for "unknown parameter" and the 438 * "Unrecognized parameter" type is the same, we can 439 * construct the parameters in INIT ACK by copying the 440 * ERROR causes over. 441 */ 442 unk_param = (struct sctp_unrecognized_param *) 443 ((__u8 *)(err_chunk->chunk_hdr) + 444 sizeof(struct sctp_chunkhdr)); 445 /* Replace the cause code with the "Unrecognized parameter" 446 * parameter type. 447 */ 448 sctp_addto_chunk(repl, len, unk_param); 449 sctp_chunk_free(err_chunk); 450 } 451 452 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 453 454 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 455 456 /* 457 * Note: After sending out INIT ACK with the State Cookie parameter, 458 * "Z" MUST NOT allocate any resources, nor keep any states for the 459 * new association. Otherwise, "Z" will be vulnerable to resource 460 * attacks. 461 */ 462 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 463 464 return SCTP_DISPOSITION_DELETE_TCB; 465 466 nomem_init: 467 sctp_association_free(new_asoc); 468 nomem: 469 if (err_chunk) 470 sctp_chunk_free(err_chunk); 471 return SCTP_DISPOSITION_NOMEM; 472 } 473 474 /* 475 * Respond to a normal INIT ACK chunk. 476 * We are the side that is initiating the association. 477 * 478 * Section: 5.1 Normal Establishment of an Association, C 479 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 480 * timer and leave COOKIE-WAIT state. "A" shall then send the State 481 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 482 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 483 * 484 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 485 * DATA chunks, but it MUST be the first chunk in the packet and 486 * until the COOKIE ACK is returned the sender MUST NOT send any 487 * other packets to the peer. 488 * 489 * Verification Tag: 3.3.3 490 * If the value of the Initiate Tag in a received INIT ACK chunk is 491 * found to be 0, the receiver MUST treat it as an error and close the 492 * association by transmitting an ABORT. 493 * 494 * Inputs 495 * (endpoint, asoc, chunk) 496 * 497 * Outputs 498 * (asoc, reply_msg, msg_up, timers, counters) 499 * 500 * The return value is the disposition of the chunk. 501 */ 502 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 503 const struct sctp_endpoint *ep, 504 const struct sctp_association *asoc, 505 const union sctp_subtype type, 506 void *arg, 507 struct sctp_cmd_seq *commands) 508 { 509 struct sctp_init_chunk *initchunk; 510 struct sctp_chunk *chunk = arg; 511 struct sctp_chunk *err_chunk; 512 struct sctp_packet *packet; 513 514 if (!sctp_vtag_verify(chunk, asoc)) 515 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 516 517 /* 6.10 Bundling 518 * An endpoint MUST NOT bundle INIT, INIT ACK or 519 * SHUTDOWN COMPLETE with any other chunks. 520 */ 521 if (!chunk->singleton) 522 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 523 524 /* Make sure that the INIT-ACK chunk has a valid length */ 525 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 526 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 527 commands); 528 /* Grab the INIT header. */ 529 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 530 531 /* Verify the INIT chunk before processing it. */ 532 err_chunk = NULL; 533 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 534 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 535 &err_chunk)) { 536 537 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 538 539 /* This chunk contains fatal error. It is to be discarded. 540 * Send an ABORT, with causes. If there are no causes, 541 * then there wasn't enough memory. Just terminate 542 * the association. 543 */ 544 if (err_chunk) { 545 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 546 (__u8 *)(err_chunk->chunk_hdr) + 547 sizeof(struct sctp_chunkhdr), 548 ntohs(err_chunk->chunk_hdr->length) - 549 sizeof(struct sctp_chunkhdr)); 550 551 sctp_chunk_free(err_chunk); 552 553 if (packet) { 554 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 555 SCTP_PACKET(packet)); 556 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 557 error = SCTP_ERROR_INV_PARAM; 558 } 559 } 560 561 /* SCTP-AUTH, Section 6.3: 562 * It should be noted that if the receiver wants to tear 563 * down an association in an authenticated way only, the 564 * handling of malformed packets should not result in 565 * tearing down the association. 566 * 567 * This means that if we only want to abort associations 568 * in an authenticated way (i.e AUTH+ABORT), then we 569 * can't destroy this association just because the packet 570 * was malformed. 571 */ 572 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 573 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 574 575 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 576 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 577 asoc, chunk->transport); 578 } 579 580 /* Tag the variable length parameters. Note that we never 581 * convert the parameters in an INIT chunk. 582 */ 583 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 584 585 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 586 587 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 588 SCTP_PEER_INIT(initchunk)); 589 590 /* Reset init error count upon receipt of INIT-ACK. */ 591 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 592 593 /* 5.1 C) "A" shall stop the T1-init timer and leave 594 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 595 * timer, and enter the COOKIE-ECHOED state. 596 */ 597 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 598 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 599 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 600 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 601 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 602 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 603 604 /* SCTP-AUTH: genereate the assocition shared keys so that 605 * we can potentially signe the COOKIE-ECHO. 606 */ 607 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 608 609 /* 5.1 C) "A" shall then send the State Cookie received in the 610 * INIT ACK chunk in a COOKIE ECHO chunk, ... 611 */ 612 /* If there is any errors to report, send the ERROR chunk generated 613 * for unknown parameters as well. 614 */ 615 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 616 SCTP_CHUNK(err_chunk)); 617 618 return SCTP_DISPOSITION_CONSUME; 619 } 620 621 /* 622 * Respond to a normal COOKIE ECHO chunk. 623 * We are the side that is being asked for an association. 624 * 625 * Section: 5.1 Normal Establishment of an Association, D 626 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 627 * with a COOKIE ACK chunk after building a TCB and moving to 628 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 629 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 630 * chunk MUST be the first chunk in the packet. 631 * 632 * IMPLEMENTATION NOTE: An implementation may choose to send the 633 * Communication Up notification to the SCTP user upon reception 634 * of a valid COOKIE ECHO chunk. 635 * 636 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 637 * D) Rules for packet carrying a COOKIE ECHO 638 * 639 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 640 * Initial Tag received in the INIT ACK. 641 * 642 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 643 * 644 * Inputs 645 * (endpoint, asoc, chunk) 646 * 647 * Outputs 648 * (asoc, reply_msg, msg_up, timers, counters) 649 * 650 * The return value is the disposition of the chunk. 651 */ 652 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 653 const struct sctp_endpoint *ep, 654 const struct sctp_association *asoc, 655 const union sctp_subtype type, 656 void *arg, 657 struct sctp_cmd_seq *commands) 658 { 659 struct sctp_ulpevent *ev, *ai_ev = NULL; 660 struct sctp_association *new_asoc; 661 struct sctp_init_chunk *peer_init; 662 struct sctp_chunk *chunk = arg; 663 struct sctp_chunk *err_chk_p; 664 struct sctp_chunk *repl; 665 struct sock *sk; 666 int error = 0; 667 668 /* If the packet is an OOTB packet which is temporarily on the 669 * control endpoint, respond with an ABORT. 670 */ 671 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 672 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 673 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 674 } 675 676 /* Make sure that the COOKIE_ECHO chunk has a valid length. 677 * In this case, we check that we have enough for at least a 678 * chunk header. More detailed verification is done 679 * in sctp_unpack_cookie(). 680 */ 681 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 682 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 683 684 /* If the endpoint is not listening or if the number of associations 685 * on the TCP-style socket exceed the max backlog, respond with an 686 * ABORT. 687 */ 688 sk = ep->base.sk; 689 if (!sctp_sstate(sk, LISTENING) || 690 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 691 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 692 693 /* "Decode" the chunk. We have no optional parameters so we 694 * are in good shape. 695 */ 696 chunk->subh.cookie_hdr = 697 (struct sctp_signed_cookie *)chunk->skb->data; 698 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 699 sizeof(struct sctp_chunkhdr))) 700 goto nomem; 701 702 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 703 * "Z" will reply with a COOKIE ACK chunk after building a TCB 704 * and moving to the ESTABLISHED state. 705 */ 706 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 707 &err_chk_p); 708 709 /* FIXME: 710 * If the re-build failed, what is the proper error path 711 * from here? 712 * 713 * [We should abort the association. --piggy] 714 */ 715 if (!new_asoc) { 716 /* FIXME: Several errors are possible. A bad cookie should 717 * be silently discarded, but think about logging it too. 718 */ 719 switch (error) { 720 case -SCTP_IERROR_NOMEM: 721 goto nomem; 722 723 case -SCTP_IERROR_STALE_COOKIE: 724 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 725 err_chk_p); 726 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 727 728 case -SCTP_IERROR_BAD_SIG: 729 default: 730 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 731 } 732 } 733 734 735 /* Delay state machine commands until later. 736 * 737 * Re-build the bind address for the association is done in 738 * the sctp_unpack_cookie() already. 739 */ 740 /* This is a brand-new association, so these are not yet side 741 * effects--it is safe to run them here. 742 */ 743 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 744 745 if (!sctp_process_init(new_asoc, chunk, 746 &chunk->subh.cookie_hdr->c.peer_addr, 747 peer_init, GFP_ATOMIC)) 748 goto nomem_init; 749 750 /* SCTP-AUTH: Now that we've populate required fields in 751 * sctp_process_init, set up the assocaition shared keys as 752 * necessary so that we can potentially authenticate the ACK 753 */ 754 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 755 if (error) 756 goto nomem_init; 757 758 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 759 * is supposed to be authenticated and we have to do delayed 760 * authentication. We've just recreated the association using 761 * the information in the cookie and now it's much easier to 762 * do the authentication. 763 */ 764 if (chunk->auth_chunk) { 765 struct sctp_chunk auth; 766 enum sctp_ierror ret; 767 768 /* Make sure that we and the peer are AUTH capable */ 769 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) { 770 sctp_association_free(new_asoc); 771 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 772 } 773 774 /* set-up our fake chunk so that we can process it */ 775 auth.skb = chunk->auth_chunk; 776 auth.asoc = chunk->asoc; 777 auth.sctp_hdr = chunk->sctp_hdr; 778 auth.chunk_hdr = (struct sctp_chunkhdr *) 779 skb_push(chunk->auth_chunk, 780 sizeof(struct sctp_chunkhdr)); 781 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 782 auth.transport = chunk->transport; 783 784 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 785 if (ret != SCTP_IERROR_NO_ERROR) { 786 sctp_association_free(new_asoc); 787 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 788 } 789 } 790 791 repl = sctp_make_cookie_ack(new_asoc, chunk); 792 if (!repl) 793 goto nomem_init; 794 795 /* RFC 2960 5.1 Normal Establishment of an Association 796 * 797 * D) IMPLEMENTATION NOTE: An implementation may choose to 798 * send the Communication Up notification to the SCTP user 799 * upon reception of a valid COOKIE ECHO chunk. 800 */ 801 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 802 new_asoc->c.sinit_num_ostreams, 803 new_asoc->c.sinit_max_instreams, 804 NULL, GFP_ATOMIC); 805 if (!ev) 806 goto nomem_ev; 807 808 /* Sockets API Draft Section 5.3.1.6 809 * When a peer sends a Adaptation Layer Indication parameter , SCTP 810 * delivers this notification to inform the application that of the 811 * peers requested adaptation layer. 812 */ 813 if (new_asoc->peer.adaptation_ind) { 814 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 815 GFP_ATOMIC); 816 if (!ai_ev) 817 goto nomem_aiev; 818 } 819 820 /* Add all the state machine commands now since we've created 821 * everything. This way we don't introduce memory corruptions 822 * during side-effect processing and correclty count established 823 * associations. 824 */ 825 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 826 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 827 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 828 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 829 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 830 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 831 832 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 833 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 834 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 835 836 /* This will send the COOKIE ACK */ 837 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 838 839 /* Queue the ASSOC_CHANGE event */ 840 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 841 842 /* Send up the Adaptation Layer Indication event */ 843 if (ai_ev) 844 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 845 SCTP_ULPEVENT(ai_ev)); 846 847 return SCTP_DISPOSITION_CONSUME; 848 849 nomem_aiev: 850 sctp_ulpevent_free(ev); 851 nomem_ev: 852 sctp_chunk_free(repl); 853 nomem_init: 854 sctp_association_free(new_asoc); 855 nomem: 856 return SCTP_DISPOSITION_NOMEM; 857 } 858 859 /* 860 * Respond to a normal COOKIE ACK chunk. 861 * We are the side that is asking for an association. 862 * 863 * RFC 2960 5.1 Normal Establishment of an Association 864 * 865 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 866 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 867 * timer. It may also notify its ULP about the successful 868 * establishment of the association with a Communication Up 869 * notification (see Section 10). 870 * 871 * Verification Tag: 872 * Inputs 873 * (endpoint, asoc, chunk) 874 * 875 * Outputs 876 * (asoc, reply_msg, msg_up, timers, counters) 877 * 878 * The return value is the disposition of the chunk. 879 */ 880 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 881 const struct sctp_endpoint *ep, 882 const struct sctp_association *asoc, 883 const union sctp_subtype type, 884 void *arg, 885 struct sctp_cmd_seq *commands) 886 { 887 struct sctp_chunk *chunk = arg; 888 struct sctp_ulpevent *ev; 889 890 if (!sctp_vtag_verify(chunk, asoc)) 891 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 892 893 /* Verify that the chunk length for the COOKIE-ACK is OK. 894 * If we don't do this, any bundled chunks may be junked. 895 */ 896 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 897 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 898 commands); 899 900 /* Reset init error count upon receipt of COOKIE-ACK, 901 * to avoid problems with the managemement of this 902 * counter in stale cookie situations when a transition back 903 * from the COOKIE-ECHOED state to the COOKIE-WAIT 904 * state is performed. 905 */ 906 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 907 908 /* RFC 2960 5.1 Normal Establishment of an Association 909 * 910 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 911 * from the COOKIE-ECHOED state to the ESTABLISHED state, 912 * stopping the T1-cookie timer. 913 */ 914 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 915 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 916 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 917 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 918 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 919 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 920 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 921 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 922 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 923 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 924 925 /* It may also notify its ULP about the successful 926 * establishment of the association with a Communication Up 927 * notification (see Section 10). 928 */ 929 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 930 0, asoc->c.sinit_num_ostreams, 931 asoc->c.sinit_max_instreams, 932 NULL, GFP_ATOMIC); 933 934 if (!ev) 935 goto nomem; 936 937 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 938 939 /* Sockets API Draft Section 5.3.1.6 940 * When a peer sends a Adaptation Layer Indication parameter , SCTP 941 * delivers this notification to inform the application that of the 942 * peers requested adaptation layer. 943 */ 944 if (asoc->peer.adaptation_ind) { 945 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 946 if (!ev) 947 goto nomem; 948 949 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 950 SCTP_ULPEVENT(ev)); 951 } 952 953 return SCTP_DISPOSITION_CONSUME; 954 nomem: 955 return SCTP_DISPOSITION_NOMEM; 956 } 957 958 /* Generate and sendout a heartbeat packet. */ 959 static enum sctp_disposition sctp_sf_heartbeat( 960 const struct sctp_endpoint *ep, 961 const struct sctp_association *asoc, 962 const union sctp_subtype type, 963 void *arg, 964 struct sctp_cmd_seq *commands) 965 { 966 struct sctp_transport *transport = (struct sctp_transport *) arg; 967 struct sctp_chunk *reply; 968 969 /* Send a heartbeat to our peer. */ 970 reply = sctp_make_heartbeat(asoc, transport); 971 if (!reply) 972 return SCTP_DISPOSITION_NOMEM; 973 974 /* Set rto_pending indicating that an RTT measurement 975 * is started with this heartbeat chunk. 976 */ 977 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 978 SCTP_TRANSPORT(transport)); 979 980 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 981 return SCTP_DISPOSITION_CONSUME; 982 } 983 984 /* Generate a HEARTBEAT packet on the given transport. */ 985 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 986 const struct sctp_endpoint *ep, 987 const struct sctp_association *asoc, 988 const union sctp_subtype type, 989 void *arg, 990 struct sctp_cmd_seq *commands) 991 { 992 struct sctp_transport *transport = (struct sctp_transport *) arg; 993 994 if (asoc->overall_error_count >= asoc->max_retrans) { 995 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 996 SCTP_ERROR(ETIMEDOUT)); 997 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 998 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 999 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1000 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1001 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1002 return SCTP_DISPOSITION_DELETE_TCB; 1003 } 1004 1005 /* Section 3.3.5. 1006 * The Sender-specific Heartbeat Info field should normally include 1007 * information about the sender's current time when this HEARTBEAT 1008 * chunk is sent and the destination transport address to which this 1009 * HEARTBEAT is sent (see Section 8.3). 1010 */ 1011 1012 if (transport->param_flags & SPP_HB_ENABLE) { 1013 if (SCTP_DISPOSITION_NOMEM == 1014 sctp_sf_heartbeat(ep, asoc, type, arg, 1015 commands)) 1016 return SCTP_DISPOSITION_NOMEM; 1017 1018 /* Set transport error counter and association error counter 1019 * when sending heartbeat. 1020 */ 1021 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1022 SCTP_TRANSPORT(transport)); 1023 } 1024 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1025 SCTP_TRANSPORT(transport)); 1026 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1027 SCTP_TRANSPORT(transport)); 1028 1029 return SCTP_DISPOSITION_CONSUME; 1030 } 1031 1032 /* resend asoc strreset_chunk. */ 1033 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1034 const struct sctp_endpoint *ep, 1035 const struct sctp_association *asoc, 1036 const union sctp_subtype type, 1037 void *arg, 1038 struct sctp_cmd_seq *commands) 1039 { 1040 struct sctp_transport *transport = arg; 1041 1042 if (asoc->overall_error_count >= asoc->max_retrans) { 1043 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1044 SCTP_ERROR(ETIMEDOUT)); 1045 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1046 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1047 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1048 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1049 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1050 return SCTP_DISPOSITION_DELETE_TCB; 1051 } 1052 1053 sctp_chunk_hold(asoc->strreset_chunk); 1054 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1055 SCTP_CHUNK(asoc->strreset_chunk)); 1056 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1057 1058 return SCTP_DISPOSITION_CONSUME; 1059 } 1060 1061 /* 1062 * Process an heartbeat request. 1063 * 1064 * Section: 8.3 Path Heartbeat 1065 * The receiver of the HEARTBEAT should immediately respond with a 1066 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1067 * from the received HEARTBEAT chunk. 1068 * 1069 * Verification Tag: 8.5 Verification Tag [Normal verification] 1070 * When receiving an SCTP packet, the endpoint MUST ensure that the 1071 * value in the Verification Tag field of the received SCTP packet 1072 * matches its own Tag. If the received Verification Tag value does not 1073 * match the receiver's own tag value, the receiver shall silently 1074 * discard the packet and shall not process it any further except for 1075 * those cases listed in Section 8.5.1 below. 1076 * 1077 * Inputs 1078 * (endpoint, asoc, chunk) 1079 * 1080 * Outputs 1081 * (asoc, reply_msg, msg_up, timers, counters) 1082 * 1083 * The return value is the disposition of the chunk. 1084 */ 1085 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1086 const struct sctp_endpoint *ep, 1087 const struct sctp_association *asoc, 1088 const union sctp_subtype type, 1089 void *arg, struct sctp_cmd_seq *commands) 1090 { 1091 struct sctp_paramhdr *param_hdr; 1092 struct sctp_chunk *chunk = arg; 1093 struct sctp_chunk *reply; 1094 size_t paylen = 0; 1095 1096 if (!sctp_vtag_verify(chunk, asoc)) 1097 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1098 1099 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1100 if (!sctp_chunk_length_valid(chunk, 1101 sizeof(struct sctp_heartbeat_chunk))) 1102 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1103 commands); 1104 1105 /* 8.3 The receiver of the HEARTBEAT should immediately 1106 * respond with a HEARTBEAT ACK that contains the Heartbeat 1107 * Information field copied from the received HEARTBEAT chunk. 1108 */ 1109 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1110 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1111 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1112 1113 if (ntohs(param_hdr->length) > paylen) 1114 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1115 param_hdr, commands); 1116 1117 if (!pskb_pull(chunk->skb, paylen)) 1118 goto nomem; 1119 1120 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1121 if (!reply) 1122 goto nomem; 1123 1124 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1125 return SCTP_DISPOSITION_CONSUME; 1126 1127 nomem: 1128 return SCTP_DISPOSITION_NOMEM; 1129 } 1130 1131 /* 1132 * Process the returning HEARTBEAT ACK. 1133 * 1134 * Section: 8.3 Path Heartbeat 1135 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1136 * should clear the error counter of the destination transport 1137 * address to which the HEARTBEAT was sent, and mark the destination 1138 * transport address as active if it is not so marked. The endpoint may 1139 * optionally report to the upper layer when an inactive destination 1140 * address is marked as active due to the reception of the latest 1141 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1142 * clear the association overall error count as well (as defined 1143 * in section 8.1). 1144 * 1145 * The receiver of the HEARTBEAT ACK should also perform an RTT 1146 * measurement for that destination transport address using the time 1147 * value carried in the HEARTBEAT ACK chunk. 1148 * 1149 * Verification Tag: 8.5 Verification Tag [Normal verification] 1150 * 1151 * Inputs 1152 * (endpoint, asoc, chunk) 1153 * 1154 * Outputs 1155 * (asoc, reply_msg, msg_up, timers, counters) 1156 * 1157 * The return value is the disposition of the chunk. 1158 */ 1159 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1160 const struct sctp_endpoint *ep, 1161 const struct sctp_association *asoc, 1162 const union sctp_subtype type, 1163 void *arg, 1164 struct sctp_cmd_seq *commands) 1165 { 1166 struct sctp_sender_hb_info *hbinfo; 1167 struct sctp_chunk *chunk = arg; 1168 struct sctp_transport *link; 1169 unsigned long max_interval; 1170 union sctp_addr from_addr; 1171 1172 if (!sctp_vtag_verify(chunk, asoc)) 1173 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1174 1175 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1176 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1177 sizeof(*hbinfo))) 1178 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1179 commands); 1180 1181 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1182 /* Make sure that the length of the parameter is what we expect */ 1183 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1184 return SCTP_DISPOSITION_DISCARD; 1185 1186 from_addr = hbinfo->daddr; 1187 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1188 1189 /* This should never happen, but lets log it if so. */ 1190 if (unlikely(!link)) { 1191 if (from_addr.sa.sa_family == AF_INET6) { 1192 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1193 __func__, 1194 asoc, 1195 &from_addr.v6.sin6_addr); 1196 } else { 1197 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1198 __func__, 1199 asoc, 1200 &from_addr.v4.sin_addr.s_addr); 1201 } 1202 return SCTP_DISPOSITION_DISCARD; 1203 } 1204 1205 /* Validate the 64-bit random nonce. */ 1206 if (hbinfo->hb_nonce != link->hb_nonce) 1207 return SCTP_DISPOSITION_DISCARD; 1208 1209 max_interval = link->hbinterval + link->rto; 1210 1211 /* Check if the timestamp looks valid. */ 1212 if (time_after(hbinfo->sent_at, jiffies) || 1213 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1214 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1215 "for transport:%p\n", __func__, link); 1216 1217 return SCTP_DISPOSITION_DISCARD; 1218 } 1219 1220 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1221 * the HEARTBEAT should clear the error counter of the 1222 * destination transport address to which the HEARTBEAT was 1223 * sent and mark the destination transport address as active if 1224 * it is not so marked. 1225 */ 1226 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1227 1228 return SCTP_DISPOSITION_CONSUME; 1229 } 1230 1231 /* Helper function to send out an abort for the restart 1232 * condition. 1233 */ 1234 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1235 struct sctp_chunk *init, 1236 struct sctp_cmd_seq *commands) 1237 { 1238 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1239 union sctp_addr_param *addrparm; 1240 struct sctp_errhdr *errhdr; 1241 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1242 struct sctp_endpoint *ep; 1243 struct sctp_packet *pkt; 1244 int len; 1245 1246 /* Build the error on the stack. We are way to malloc crazy 1247 * throughout the code today. 1248 */ 1249 errhdr = (struct sctp_errhdr *)buffer; 1250 addrparm = (union sctp_addr_param *)errhdr->variable; 1251 1252 /* Copy into a parm format. */ 1253 len = af->to_addr_param(ssa, addrparm); 1254 len += sizeof(*errhdr); 1255 1256 errhdr->cause = SCTP_ERROR_RESTART; 1257 errhdr->length = htons(len); 1258 1259 /* Assign to the control socket. */ 1260 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1261 1262 /* Association is NULL since this may be a restart attack and we 1263 * want to send back the attacker's vtag. 1264 */ 1265 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1266 1267 if (!pkt) 1268 goto out; 1269 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1270 1271 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1272 1273 /* Discard the rest of the inbound packet. */ 1274 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1275 1276 out: 1277 /* Even if there is no memory, treat as a failure so 1278 * the packet will get dropped. 1279 */ 1280 return 0; 1281 } 1282 1283 static bool list_has_sctp_addr(const struct list_head *list, 1284 union sctp_addr *ipaddr) 1285 { 1286 struct sctp_transport *addr; 1287 1288 list_for_each_entry(addr, list, transports) { 1289 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1290 return true; 1291 } 1292 1293 return false; 1294 } 1295 /* A restart is occurring, check to make sure no new addresses 1296 * are being added as we may be under a takeover attack. 1297 */ 1298 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1299 const struct sctp_association *asoc, 1300 struct sctp_chunk *init, 1301 struct sctp_cmd_seq *commands) 1302 { 1303 struct net *net = sock_net(new_asoc->base.sk); 1304 struct sctp_transport *new_addr; 1305 int ret = 1; 1306 1307 /* Implementor's Guide - Section 5.2.2 1308 * ... 1309 * Before responding the endpoint MUST check to see if the 1310 * unexpected INIT adds new addresses to the association. If new 1311 * addresses are added to the association, the endpoint MUST respond 1312 * with an ABORT.. 1313 */ 1314 1315 /* Search through all current addresses and make sure 1316 * we aren't adding any new ones. 1317 */ 1318 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1319 transports) { 1320 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1321 &new_addr->ipaddr)) { 1322 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1323 commands); 1324 ret = 0; 1325 break; 1326 } 1327 } 1328 1329 /* Return success if all addresses were found. */ 1330 return ret; 1331 } 1332 1333 /* Populate the verification/tie tags based on overlapping INIT 1334 * scenario. 1335 * 1336 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1337 */ 1338 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1339 const struct sctp_association *asoc) 1340 { 1341 switch (asoc->state) { 1342 1343 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1344 1345 case SCTP_STATE_COOKIE_WAIT: 1346 new_asoc->c.my_vtag = asoc->c.my_vtag; 1347 new_asoc->c.my_ttag = asoc->c.my_vtag; 1348 new_asoc->c.peer_ttag = 0; 1349 break; 1350 1351 case SCTP_STATE_COOKIE_ECHOED: 1352 new_asoc->c.my_vtag = asoc->c.my_vtag; 1353 new_asoc->c.my_ttag = asoc->c.my_vtag; 1354 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1355 break; 1356 1357 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1358 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1359 */ 1360 default: 1361 new_asoc->c.my_ttag = asoc->c.my_vtag; 1362 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1363 break; 1364 } 1365 1366 /* Other parameters for the endpoint SHOULD be copied from the 1367 * existing parameters of the association (e.g. number of 1368 * outbound streams) into the INIT ACK and cookie. 1369 */ 1370 new_asoc->rwnd = asoc->rwnd; 1371 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1372 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1373 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1374 } 1375 1376 /* 1377 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1378 * handling action. 1379 * 1380 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1381 * 1382 * Returns value representing action to be taken. These action values 1383 * correspond to Action/Description values in RFC 2960, Table 2. 1384 */ 1385 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1386 const struct sctp_association *asoc) 1387 { 1388 /* In this case, the peer may have restarted. */ 1389 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1390 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1391 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1392 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1393 return 'A'; 1394 1395 /* Collision case B. */ 1396 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1397 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1398 (0 == asoc->c.peer_vtag))) { 1399 return 'B'; 1400 } 1401 1402 /* Collision case D. */ 1403 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1404 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1405 return 'D'; 1406 1407 /* Collision case C. */ 1408 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1409 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1410 (0 == new_asoc->c.my_ttag) && 1411 (0 == new_asoc->c.peer_ttag)) 1412 return 'C'; 1413 1414 /* No match to any of the special cases; discard this packet. */ 1415 return 'E'; 1416 } 1417 1418 /* Common helper routine for both duplicate and simulataneous INIT 1419 * chunk handling. 1420 */ 1421 static enum sctp_disposition sctp_sf_do_unexpected_init( 1422 struct net *net, 1423 const struct sctp_endpoint *ep, 1424 const struct sctp_association *asoc, 1425 const union sctp_subtype type, 1426 void *arg, 1427 struct sctp_cmd_seq *commands) 1428 { 1429 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1430 struct sctp_unrecognized_param *unk_param; 1431 struct sctp_association *new_asoc; 1432 enum sctp_disposition retval; 1433 struct sctp_packet *packet; 1434 int len; 1435 1436 /* 6.10 Bundling 1437 * An endpoint MUST NOT bundle INIT, INIT ACK or 1438 * SHUTDOWN COMPLETE with any other chunks. 1439 * 1440 * IG Section 2.11.2 1441 * Furthermore, we require that the receiver of an INIT chunk MUST 1442 * enforce these rules by silently discarding an arriving packet 1443 * with an INIT chunk that is bundled with other chunks. 1444 */ 1445 if (!chunk->singleton) 1446 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1447 1448 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1449 * Tag. 1450 */ 1451 if (chunk->sctp_hdr->vtag != 0) 1452 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1453 1454 /* Make sure that the INIT chunk has a valid length. 1455 * In this case, we generate a protocol violation since we have 1456 * an association established. 1457 */ 1458 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1459 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1460 commands); 1461 /* Grab the INIT header. */ 1462 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1463 1464 /* Tag the variable length parameters. */ 1465 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1466 1467 /* Verify the INIT chunk before processing it. */ 1468 err_chunk = NULL; 1469 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1470 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1471 &err_chunk)) { 1472 /* This chunk contains fatal error. It is to be discarded. 1473 * Send an ABORT, with causes if there is any. 1474 */ 1475 if (err_chunk) { 1476 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1477 (__u8 *)(err_chunk->chunk_hdr) + 1478 sizeof(struct sctp_chunkhdr), 1479 ntohs(err_chunk->chunk_hdr->length) - 1480 sizeof(struct sctp_chunkhdr)); 1481 1482 if (packet) { 1483 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1484 SCTP_PACKET(packet)); 1485 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1486 retval = SCTP_DISPOSITION_CONSUME; 1487 } else { 1488 retval = SCTP_DISPOSITION_NOMEM; 1489 } 1490 goto cleanup; 1491 } else { 1492 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1493 commands); 1494 } 1495 } 1496 1497 /* 1498 * Other parameters for the endpoint SHOULD be copied from the 1499 * existing parameters of the association (e.g. number of 1500 * outbound streams) into the INIT ACK and cookie. 1501 * FIXME: We are copying parameters from the endpoint not the 1502 * association. 1503 */ 1504 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1505 if (!new_asoc) 1506 goto nomem; 1507 1508 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1509 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1510 goto nomem; 1511 1512 /* In the outbound INIT ACK the endpoint MUST copy its current 1513 * Verification Tag and Peers Verification tag into a reserved 1514 * place (local tie-tag and per tie-tag) within the state cookie. 1515 */ 1516 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1517 (struct sctp_init_chunk *)chunk->chunk_hdr, 1518 GFP_ATOMIC)) 1519 goto nomem; 1520 1521 /* Make sure no new addresses are being added during the 1522 * restart. Do not do this check for COOKIE-WAIT state, 1523 * since there are no peer addresses to check against. 1524 * Upon return an ABORT will have been sent if needed. 1525 */ 1526 if (!sctp_state(asoc, COOKIE_WAIT)) { 1527 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1528 commands)) { 1529 retval = SCTP_DISPOSITION_CONSUME; 1530 goto nomem_retval; 1531 } 1532 } 1533 1534 sctp_tietags_populate(new_asoc, asoc); 1535 1536 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1537 1538 /* If there are errors need to be reported for unknown parameters, 1539 * make sure to reserve enough room in the INIT ACK for them. 1540 */ 1541 len = 0; 1542 if (err_chunk) { 1543 len = ntohs(err_chunk->chunk_hdr->length) - 1544 sizeof(struct sctp_chunkhdr); 1545 } 1546 1547 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1548 if (!repl) 1549 goto nomem; 1550 1551 /* If there are errors need to be reported for unknown parameters, 1552 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1553 * parameter. 1554 */ 1555 if (err_chunk) { 1556 /* Get the "Unrecognized parameter" parameter(s) out of the 1557 * ERROR chunk generated by sctp_verify_init(). Since the 1558 * error cause code for "unknown parameter" and the 1559 * "Unrecognized parameter" type is the same, we can 1560 * construct the parameters in INIT ACK by copying the 1561 * ERROR causes over. 1562 */ 1563 unk_param = (struct sctp_unrecognized_param *) 1564 ((__u8 *)(err_chunk->chunk_hdr) + 1565 sizeof(struct sctp_chunkhdr)); 1566 /* Replace the cause code with the "Unrecognized parameter" 1567 * parameter type. 1568 */ 1569 sctp_addto_chunk(repl, len, unk_param); 1570 } 1571 1572 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1573 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1574 1575 /* 1576 * Note: After sending out INIT ACK with the State Cookie parameter, 1577 * "Z" MUST NOT allocate any resources for this new association. 1578 * Otherwise, "Z" will be vulnerable to resource attacks. 1579 */ 1580 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1581 retval = SCTP_DISPOSITION_CONSUME; 1582 1583 return retval; 1584 1585 nomem: 1586 retval = SCTP_DISPOSITION_NOMEM; 1587 nomem_retval: 1588 if (new_asoc) 1589 sctp_association_free(new_asoc); 1590 cleanup: 1591 if (err_chunk) 1592 sctp_chunk_free(err_chunk); 1593 return retval; 1594 } 1595 1596 /* 1597 * Handle simultaneous INIT. 1598 * This means we started an INIT and then we got an INIT request from 1599 * our peer. 1600 * 1601 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1602 * This usually indicates an initialization collision, i.e., each 1603 * endpoint is attempting, at about the same time, to establish an 1604 * association with the other endpoint. 1605 * 1606 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1607 * endpoint MUST respond with an INIT ACK using the same parameters it 1608 * sent in its original INIT chunk (including its Verification Tag, 1609 * unchanged). These original parameters are combined with those from the 1610 * newly received INIT chunk. The endpoint shall also generate a State 1611 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1612 * INIT to calculate the State Cookie. 1613 * 1614 * After that, the endpoint MUST NOT change its state, the T1-init 1615 * timer shall be left running and the corresponding TCB MUST NOT be 1616 * destroyed. The normal procedures for handling State Cookies when 1617 * a TCB exists will resolve the duplicate INITs to a single association. 1618 * 1619 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1620 * its Tie-Tags with the Tag information of itself and its peer (see 1621 * section 5.2.2 for a description of the Tie-Tags). 1622 * 1623 * Verification Tag: Not explicit, but an INIT can not have a valid 1624 * verification tag, so we skip the check. 1625 * 1626 * Inputs 1627 * (endpoint, asoc, chunk) 1628 * 1629 * Outputs 1630 * (asoc, reply_msg, msg_up, timers, counters) 1631 * 1632 * The return value is the disposition of the chunk. 1633 */ 1634 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1635 struct net *net, 1636 const struct sctp_endpoint *ep, 1637 const struct sctp_association *asoc, 1638 const union sctp_subtype type, 1639 void *arg, 1640 struct sctp_cmd_seq *commands) 1641 { 1642 /* Call helper to do the real work for both simulataneous and 1643 * duplicate INIT chunk handling. 1644 */ 1645 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1646 } 1647 1648 /* 1649 * Handle duplicated INIT messages. These are usually delayed 1650 * restransmissions. 1651 * 1652 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1653 * COOKIE-ECHOED and COOKIE-WAIT 1654 * 1655 * Unless otherwise stated, upon reception of an unexpected INIT for 1656 * this association, the endpoint shall generate an INIT ACK with a 1657 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1658 * current Verification Tag and peer's Verification Tag into a reserved 1659 * place within the state cookie. We shall refer to these locations as 1660 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1661 * containing this INIT ACK MUST carry a Verification Tag value equal to 1662 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1663 * MUST contain a new Initiation Tag (randomly generated see Section 1664 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1665 * existing parameters of the association (e.g. number of outbound 1666 * streams) into the INIT ACK and cookie. 1667 * 1668 * After sending out the INIT ACK, the endpoint shall take no further 1669 * actions, i.e., the existing association, including its current state, 1670 * and the corresponding TCB MUST NOT be changed. 1671 * 1672 * Note: Only when a TCB exists and the association is not in a COOKIE- 1673 * WAIT state are the Tie-Tags populated. For a normal association INIT 1674 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1675 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1676 * State Cookie are populated as specified in section 5.2.1. 1677 * 1678 * Verification Tag: Not specified, but an INIT has no way of knowing 1679 * what the verification tag could be, so we ignore it. 1680 * 1681 * Inputs 1682 * (endpoint, asoc, chunk) 1683 * 1684 * Outputs 1685 * (asoc, reply_msg, msg_up, timers, counters) 1686 * 1687 * The return value is the disposition of the chunk. 1688 */ 1689 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1690 struct net *net, 1691 const struct sctp_endpoint *ep, 1692 const struct sctp_association *asoc, 1693 const union sctp_subtype type, 1694 void *arg, 1695 struct sctp_cmd_seq *commands) 1696 { 1697 /* Call helper to do the real work for both simulataneous and 1698 * duplicate INIT chunk handling. 1699 */ 1700 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1701 } 1702 1703 1704 /* 1705 * Unexpected INIT-ACK handler. 1706 * 1707 * Section 5.2.3 1708 * If an INIT ACK received by an endpoint in any state other than the 1709 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1710 * An unexpected INIT ACK usually indicates the processing of an old or 1711 * duplicated INIT chunk. 1712 */ 1713 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1714 struct net *net, 1715 const struct sctp_endpoint *ep, 1716 const struct sctp_association *asoc, 1717 const union sctp_subtype type, 1718 void *arg, 1719 struct sctp_cmd_seq *commands) 1720 { 1721 /* Per the above section, we'll discard the chunk if we have an 1722 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1723 */ 1724 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1725 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1726 else 1727 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1728 } 1729 1730 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1731 * 1732 * Section 5.2.4 1733 * A) In this case, the peer may have restarted. 1734 */ 1735 static enum sctp_disposition sctp_sf_do_dupcook_a( 1736 struct net *net, 1737 const struct sctp_endpoint *ep, 1738 const struct sctp_association *asoc, 1739 struct sctp_chunk *chunk, 1740 struct sctp_cmd_seq *commands, 1741 struct sctp_association *new_asoc) 1742 { 1743 struct sctp_init_chunk *peer_init; 1744 enum sctp_disposition disposition; 1745 struct sctp_ulpevent *ev; 1746 struct sctp_chunk *repl; 1747 struct sctp_chunk *err; 1748 1749 /* new_asoc is a brand-new association, so these are not yet 1750 * side effects--it is safe to run them here. 1751 */ 1752 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1753 1754 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1755 GFP_ATOMIC)) 1756 goto nomem; 1757 1758 /* Make sure no new addresses are being added during the 1759 * restart. Though this is a pretty complicated attack 1760 * since you'd have to get inside the cookie. 1761 */ 1762 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1763 return SCTP_DISPOSITION_CONSUME; 1764 } 1765 1766 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1767 * the peer has restarted (Action A), it MUST NOT setup a new 1768 * association but instead resend the SHUTDOWN ACK and send an ERROR 1769 * chunk with a "Cookie Received while Shutting Down" error cause to 1770 * its peer. 1771 */ 1772 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1773 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1774 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1775 chunk, commands); 1776 if (SCTP_DISPOSITION_NOMEM == disposition) 1777 goto nomem; 1778 1779 err = sctp_make_op_error(asoc, chunk, 1780 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1781 NULL, 0, 0); 1782 if (err) 1783 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1784 SCTP_CHUNK(err)); 1785 1786 return SCTP_DISPOSITION_CONSUME; 1787 } 1788 1789 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1790 * data. Consider the optional choice of resending of this data. 1791 */ 1792 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1793 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1794 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1795 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1796 1797 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1798 * and ASCONF-ACK cache. 1799 */ 1800 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1801 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1802 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1803 1804 repl = sctp_make_cookie_ack(new_asoc, chunk); 1805 if (!repl) 1806 goto nomem; 1807 1808 /* Report association restart to upper layer. */ 1809 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1810 new_asoc->c.sinit_num_ostreams, 1811 new_asoc->c.sinit_max_instreams, 1812 NULL, GFP_ATOMIC); 1813 if (!ev) 1814 goto nomem_ev; 1815 1816 /* Update the content of current association. */ 1817 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1818 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1819 if (sctp_state(asoc, SHUTDOWN_PENDING) && 1820 (sctp_sstate(asoc->base.sk, CLOSING) || 1821 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1822 /* if were currently in SHUTDOWN_PENDING, but the socket 1823 * has been closed by user, don't transition to ESTABLISHED. 1824 * Instead trigger SHUTDOWN bundled with COOKIE_ACK. 1825 */ 1826 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1827 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1828 SCTP_ST_CHUNK(0), NULL, 1829 commands); 1830 } else { 1831 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1832 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1833 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1834 } 1835 return SCTP_DISPOSITION_CONSUME; 1836 1837 nomem_ev: 1838 sctp_chunk_free(repl); 1839 nomem: 1840 return SCTP_DISPOSITION_NOMEM; 1841 } 1842 1843 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1844 * 1845 * Section 5.2.4 1846 * B) In this case, both sides may be attempting to start an association 1847 * at about the same time but the peer endpoint started its INIT 1848 * after responding to the local endpoint's INIT 1849 */ 1850 /* This case represents an initialization collision. */ 1851 static enum sctp_disposition sctp_sf_do_dupcook_b( 1852 struct net *net, 1853 const struct sctp_endpoint *ep, 1854 const struct sctp_association *asoc, 1855 struct sctp_chunk *chunk, 1856 struct sctp_cmd_seq *commands, 1857 struct sctp_association *new_asoc) 1858 { 1859 struct sctp_init_chunk *peer_init; 1860 struct sctp_chunk *repl; 1861 1862 /* new_asoc is a brand-new association, so these are not yet 1863 * side effects--it is safe to run them here. 1864 */ 1865 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1866 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1867 GFP_ATOMIC)) 1868 goto nomem; 1869 1870 /* Update the content of current association. */ 1871 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1872 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1873 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1874 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1875 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1876 1877 repl = sctp_make_cookie_ack(new_asoc, chunk); 1878 if (!repl) 1879 goto nomem; 1880 1881 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1882 1883 /* RFC 2960 5.1 Normal Establishment of an Association 1884 * 1885 * D) IMPLEMENTATION NOTE: An implementation may choose to 1886 * send the Communication Up notification to the SCTP user 1887 * upon reception of a valid COOKIE ECHO chunk. 1888 * 1889 * Sadly, this needs to be implemented as a side-effect, because 1890 * we are not guaranteed to have set the association id of the real 1891 * association and so these notifications need to be delayed until 1892 * the association id is allocated. 1893 */ 1894 1895 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1896 1897 /* Sockets API Draft Section 5.3.1.6 1898 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1899 * delivers this notification to inform the application that of the 1900 * peers requested adaptation layer. 1901 * 1902 * This also needs to be done as a side effect for the same reason as 1903 * above. 1904 */ 1905 if (asoc->peer.adaptation_ind) 1906 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1907 1908 return SCTP_DISPOSITION_CONSUME; 1909 1910 nomem: 1911 return SCTP_DISPOSITION_NOMEM; 1912 } 1913 1914 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1915 * 1916 * Section 5.2.4 1917 * C) In this case, the local endpoint's cookie has arrived late. 1918 * Before it arrived, the local endpoint sent an INIT and received an 1919 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1920 * but a new tag of its own. 1921 */ 1922 /* This case represents an initialization collision. */ 1923 static enum sctp_disposition sctp_sf_do_dupcook_c( 1924 struct net *net, 1925 const struct sctp_endpoint *ep, 1926 const struct sctp_association *asoc, 1927 struct sctp_chunk *chunk, 1928 struct sctp_cmd_seq *commands, 1929 struct sctp_association *new_asoc) 1930 { 1931 /* The cookie should be silently discarded. 1932 * The endpoint SHOULD NOT change states and should leave 1933 * any timers running. 1934 */ 1935 return SCTP_DISPOSITION_DISCARD; 1936 } 1937 1938 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1939 * 1940 * Section 5.2.4 1941 * 1942 * D) When both local and remote tags match the endpoint should always 1943 * enter the ESTABLISHED state, if it has not already done so. 1944 */ 1945 /* This case represents an initialization collision. */ 1946 static enum sctp_disposition sctp_sf_do_dupcook_d( 1947 struct net *net, 1948 const struct sctp_endpoint *ep, 1949 const struct sctp_association *asoc, 1950 struct sctp_chunk *chunk, 1951 struct sctp_cmd_seq *commands, 1952 struct sctp_association *new_asoc) 1953 { 1954 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1955 struct sctp_chunk *repl; 1956 1957 /* Clarification from Implementor's Guide: 1958 * D) When both local and remote tags match the endpoint should 1959 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1960 * It should stop any cookie timer that may be running and send 1961 * a COOKIE ACK. 1962 */ 1963 1964 /* Don't accidentally move back into established state. */ 1965 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1966 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1967 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1968 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1969 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1970 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1971 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1972 SCTP_NULL()); 1973 1974 /* RFC 2960 5.1 Normal Establishment of an Association 1975 * 1976 * D) IMPLEMENTATION NOTE: An implementation may choose 1977 * to send the Communication Up notification to the 1978 * SCTP user upon reception of a valid COOKIE 1979 * ECHO chunk. 1980 */ 1981 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1982 SCTP_COMM_UP, 0, 1983 asoc->c.sinit_num_ostreams, 1984 asoc->c.sinit_max_instreams, 1985 NULL, GFP_ATOMIC); 1986 if (!ev) 1987 goto nomem; 1988 1989 /* Sockets API Draft Section 5.3.1.6 1990 * When a peer sends a Adaptation Layer Indication parameter, 1991 * SCTP delivers this notification to inform the application 1992 * that of the peers requested adaptation layer. 1993 */ 1994 if (asoc->peer.adaptation_ind) { 1995 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1996 GFP_ATOMIC); 1997 if (!ai_ev) 1998 goto nomem; 1999 2000 } 2001 } 2002 2003 repl = sctp_make_cookie_ack(new_asoc, chunk); 2004 if (!repl) 2005 goto nomem; 2006 2007 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2008 2009 if (ev) 2010 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2011 SCTP_ULPEVENT(ev)); 2012 if (ai_ev) 2013 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2014 SCTP_ULPEVENT(ai_ev)); 2015 2016 return SCTP_DISPOSITION_CONSUME; 2017 2018 nomem: 2019 if (ai_ev) 2020 sctp_ulpevent_free(ai_ev); 2021 if (ev) 2022 sctp_ulpevent_free(ev); 2023 return SCTP_DISPOSITION_NOMEM; 2024 } 2025 2026 /* 2027 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2028 * chunk was retransmitted and then delayed in the network. 2029 * 2030 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2031 * 2032 * Verification Tag: None. Do cookie validation. 2033 * 2034 * Inputs 2035 * (endpoint, asoc, chunk) 2036 * 2037 * Outputs 2038 * (asoc, reply_msg, msg_up, timers, counters) 2039 * 2040 * The return value is the disposition of the chunk. 2041 */ 2042 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2043 struct net *net, 2044 const struct sctp_endpoint *ep, 2045 const struct sctp_association *asoc, 2046 const union sctp_subtype type, 2047 void *arg, 2048 struct sctp_cmd_seq *commands) 2049 { 2050 struct sctp_association *new_asoc; 2051 struct sctp_chunk *chunk = arg; 2052 enum sctp_disposition retval; 2053 struct sctp_chunk *err_chk_p; 2054 int error = 0; 2055 char action; 2056 2057 /* Make sure that the chunk has a valid length from the protocol 2058 * perspective. In this case check to make sure we have at least 2059 * enough for the chunk header. Cookie length verification is 2060 * done later. 2061 */ 2062 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2063 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2064 commands); 2065 2066 /* "Decode" the chunk. We have no optional parameters so we 2067 * are in good shape. 2068 */ 2069 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2070 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2071 sizeof(struct sctp_chunkhdr))) 2072 goto nomem; 2073 2074 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2075 * of a duplicate COOKIE ECHO match the Verification Tags of the 2076 * current association, consider the State Cookie valid even if 2077 * the lifespan is exceeded. 2078 */ 2079 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2080 &err_chk_p); 2081 2082 /* FIXME: 2083 * If the re-build failed, what is the proper error path 2084 * from here? 2085 * 2086 * [We should abort the association. --piggy] 2087 */ 2088 if (!new_asoc) { 2089 /* FIXME: Several errors are possible. A bad cookie should 2090 * be silently discarded, but think about logging it too. 2091 */ 2092 switch (error) { 2093 case -SCTP_IERROR_NOMEM: 2094 goto nomem; 2095 2096 case -SCTP_IERROR_STALE_COOKIE: 2097 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2098 err_chk_p); 2099 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2100 case -SCTP_IERROR_BAD_SIG: 2101 default: 2102 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2103 } 2104 } 2105 2106 /* Set temp so that it won't be added into hashtable */ 2107 new_asoc->temp = 1; 2108 2109 /* Compare the tie_tag in cookie with the verification tag of 2110 * current association. 2111 */ 2112 action = sctp_tietags_compare(new_asoc, asoc); 2113 2114 switch (action) { 2115 case 'A': /* Association restart. */ 2116 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2117 new_asoc); 2118 break; 2119 2120 case 'B': /* Collision case B. */ 2121 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2122 new_asoc); 2123 break; 2124 2125 case 'C': /* Collision case C. */ 2126 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2127 new_asoc); 2128 break; 2129 2130 case 'D': /* Collision case D. */ 2131 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2132 new_asoc); 2133 break; 2134 2135 default: /* Discard packet for all others. */ 2136 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2137 break; 2138 } 2139 2140 /* Delete the tempory new association. */ 2141 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2142 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2143 2144 /* Restore association pointer to provide SCTP command interpeter 2145 * with a valid context in case it needs to manipulate 2146 * the queues */ 2147 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2148 SCTP_ASOC((struct sctp_association *)asoc)); 2149 2150 return retval; 2151 2152 nomem: 2153 return SCTP_DISPOSITION_NOMEM; 2154 } 2155 2156 /* 2157 * Process an ABORT. (SHUTDOWN-PENDING state) 2158 * 2159 * See sctp_sf_do_9_1_abort(). 2160 */ 2161 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2162 struct net *net, 2163 const struct sctp_endpoint *ep, 2164 const struct sctp_association *asoc, 2165 const union sctp_subtype type, 2166 void *arg, 2167 struct sctp_cmd_seq *commands) 2168 { 2169 struct sctp_chunk *chunk = arg; 2170 2171 if (!sctp_vtag_verify_either(chunk, asoc)) 2172 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2173 2174 /* Make sure that the ABORT chunk has a valid length. 2175 * Since this is an ABORT chunk, we have to discard it 2176 * because of the following text: 2177 * RFC 2960, Section 3.3.7 2178 * If an endpoint receives an ABORT with a format error or for an 2179 * association that doesn't exist, it MUST silently discard it. 2180 * Because the length is "invalid", we can't really discard just 2181 * as we do not know its true length. So, to be safe, discard the 2182 * packet. 2183 */ 2184 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2185 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2186 2187 /* ADD-IP: Special case for ABORT chunks 2188 * F4) One special consideration is that ABORT Chunks arriving 2189 * destined to the IP address being deleted MUST be 2190 * ignored (see Section 5.3.1 for further details). 2191 */ 2192 if (SCTP_ADDR_DEL == 2193 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2194 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2195 2196 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2197 } 2198 2199 /* 2200 * Process an ABORT. (SHUTDOWN-SENT state) 2201 * 2202 * See sctp_sf_do_9_1_abort(). 2203 */ 2204 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2205 struct net *net, 2206 const struct sctp_endpoint *ep, 2207 const struct sctp_association *asoc, 2208 const union sctp_subtype type, 2209 void *arg, 2210 struct sctp_cmd_seq *commands) 2211 { 2212 struct sctp_chunk *chunk = arg; 2213 2214 if (!sctp_vtag_verify_either(chunk, asoc)) 2215 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2216 2217 /* Make sure that the ABORT chunk has a valid length. 2218 * Since this is an ABORT chunk, we have to discard it 2219 * because of the following text: 2220 * RFC 2960, Section 3.3.7 2221 * If an endpoint receives an ABORT with a format error or for an 2222 * association that doesn't exist, it MUST silently discard it. 2223 * Because the length is "invalid", we can't really discard just 2224 * as we do not know its true length. So, to be safe, discard the 2225 * packet. 2226 */ 2227 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2228 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2229 2230 /* ADD-IP: Special case for ABORT chunks 2231 * F4) One special consideration is that ABORT Chunks arriving 2232 * destined to the IP address being deleted MUST be 2233 * ignored (see Section 5.3.1 for further details). 2234 */ 2235 if (SCTP_ADDR_DEL == 2236 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2237 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2238 2239 /* Stop the T2-shutdown timer. */ 2240 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2241 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2242 2243 /* Stop the T5-shutdown guard timer. */ 2244 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2245 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2246 2247 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2248 } 2249 2250 /* 2251 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2252 * 2253 * See sctp_sf_do_9_1_abort(). 2254 */ 2255 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2256 struct net *net, 2257 const struct sctp_endpoint *ep, 2258 const struct sctp_association *asoc, 2259 const union sctp_subtype type, 2260 void *arg, 2261 struct sctp_cmd_seq *commands) 2262 { 2263 /* The same T2 timer, so we should be able to use 2264 * common function with the SHUTDOWN-SENT state. 2265 */ 2266 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2267 } 2268 2269 /* 2270 * Handle an Error received in COOKIE_ECHOED state. 2271 * 2272 * Only handle the error type of stale COOKIE Error, the other errors will 2273 * be ignored. 2274 * 2275 * Inputs 2276 * (endpoint, asoc, chunk) 2277 * 2278 * Outputs 2279 * (asoc, reply_msg, msg_up, timers, counters) 2280 * 2281 * The return value is the disposition of the chunk. 2282 */ 2283 enum sctp_disposition sctp_sf_cookie_echoed_err( 2284 struct net *net, 2285 const struct sctp_endpoint *ep, 2286 const struct sctp_association *asoc, 2287 const union sctp_subtype type, 2288 void *arg, 2289 struct sctp_cmd_seq *commands) 2290 { 2291 struct sctp_chunk *chunk = arg; 2292 struct sctp_errhdr *err; 2293 2294 if (!sctp_vtag_verify(chunk, asoc)) 2295 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2296 2297 /* Make sure that the ERROR chunk has a valid length. 2298 * The parameter walking depends on this as well. 2299 */ 2300 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2301 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2302 commands); 2303 2304 /* Process the error here */ 2305 /* FUTURE FIXME: When PR-SCTP related and other optional 2306 * parms are emitted, this will have to change to handle multiple 2307 * errors. 2308 */ 2309 sctp_walk_errors(err, chunk->chunk_hdr) { 2310 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2311 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2312 arg, commands); 2313 } 2314 2315 /* It is possible to have malformed error causes, and that 2316 * will cause us to end the walk early. However, since 2317 * we are discarding the packet, there should be no adverse 2318 * affects. 2319 */ 2320 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2321 } 2322 2323 /* 2324 * Handle a Stale COOKIE Error 2325 * 2326 * Section: 5.2.6 Handle Stale COOKIE Error 2327 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2328 * one of the following three alternatives. 2329 * ... 2330 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2331 * Preservative parameter requesting an extension to the lifetime of 2332 * the State Cookie. When calculating the time extension, an 2333 * implementation SHOULD use the RTT information measured based on the 2334 * previous COOKIE ECHO / ERROR exchange, and should add no more 2335 * than 1 second beyond the measured RTT, due to long State Cookie 2336 * lifetimes making the endpoint more subject to a replay attack. 2337 * 2338 * Verification Tag: Not explicit, but safe to ignore. 2339 * 2340 * Inputs 2341 * (endpoint, asoc, chunk) 2342 * 2343 * Outputs 2344 * (asoc, reply_msg, msg_up, timers, counters) 2345 * 2346 * The return value is the disposition of the chunk. 2347 */ 2348 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2349 struct net *net, 2350 const struct sctp_endpoint *ep, 2351 const struct sctp_association *asoc, 2352 const union sctp_subtype type, 2353 void *arg, 2354 struct sctp_cmd_seq *commands) 2355 { 2356 int attempts = asoc->init_err_counter + 1; 2357 struct sctp_chunk *chunk = arg, *reply; 2358 struct sctp_cookie_preserve_param bht; 2359 struct sctp_bind_addr *bp; 2360 struct sctp_errhdr *err; 2361 u32 stale; 2362 2363 if (attempts > asoc->max_init_attempts) { 2364 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2365 SCTP_ERROR(ETIMEDOUT)); 2366 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2367 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2368 return SCTP_DISPOSITION_DELETE_TCB; 2369 } 2370 2371 err = (struct sctp_errhdr *)(chunk->skb->data); 2372 2373 /* When calculating the time extension, an implementation 2374 * SHOULD use the RTT information measured based on the 2375 * previous COOKIE ECHO / ERROR exchange, and should add no 2376 * more than 1 second beyond the measured RTT, due to long 2377 * State Cookie lifetimes making the endpoint more subject to 2378 * a replay attack. 2379 * Measure of Staleness's unit is usec. (1/1000000 sec) 2380 * Suggested Cookie Life-span Increment's unit is msec. 2381 * (1/1000 sec) 2382 * In general, if you use the suggested cookie life, the value 2383 * found in the field of measure of staleness should be doubled 2384 * to give ample time to retransmit the new cookie and thus 2385 * yield a higher probability of success on the reattempt. 2386 */ 2387 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2388 stale = (stale * 2) / 1000; 2389 2390 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2391 bht.param_hdr.length = htons(sizeof(bht)); 2392 bht.lifespan_increment = htonl(stale); 2393 2394 /* Build that new INIT chunk. */ 2395 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2396 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2397 if (!reply) 2398 goto nomem; 2399 2400 sctp_addto_chunk(reply, sizeof(bht), &bht); 2401 2402 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2403 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2404 2405 /* Stop pending T3-rtx and heartbeat timers */ 2406 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2407 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2408 2409 /* Delete non-primary peer ip addresses since we are transitioning 2410 * back to the COOKIE-WAIT state 2411 */ 2412 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2413 2414 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2415 * resend 2416 */ 2417 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2418 SCTP_TRANSPORT(asoc->peer.primary_path)); 2419 2420 /* Cast away the const modifier, as we want to just 2421 * rerun it through as a sideffect. 2422 */ 2423 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2424 2425 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2426 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2427 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2428 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2429 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2430 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2431 2432 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2433 2434 return SCTP_DISPOSITION_CONSUME; 2435 2436 nomem: 2437 return SCTP_DISPOSITION_NOMEM; 2438 } 2439 2440 /* 2441 * Process an ABORT. 2442 * 2443 * Section: 9.1 2444 * After checking the Verification Tag, the receiving endpoint shall 2445 * remove the association from its record, and shall report the 2446 * termination to its upper layer. 2447 * 2448 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2449 * B) Rules for packet carrying ABORT: 2450 * 2451 * - The endpoint shall always fill in the Verification Tag field of the 2452 * outbound packet with the destination endpoint's tag value if it 2453 * is known. 2454 * 2455 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2456 * MUST follow the procedure described in Section 8.4. 2457 * 2458 * - The receiver MUST accept the packet if the Verification Tag 2459 * matches either its own tag, OR the tag of its peer. Otherwise, the 2460 * receiver MUST silently discard the packet and take no further 2461 * action. 2462 * 2463 * Inputs 2464 * (endpoint, asoc, chunk) 2465 * 2466 * Outputs 2467 * (asoc, reply_msg, msg_up, timers, counters) 2468 * 2469 * The return value is the disposition of the chunk. 2470 */ 2471 enum sctp_disposition sctp_sf_do_9_1_abort( 2472 struct net *net, 2473 const struct sctp_endpoint *ep, 2474 const struct sctp_association *asoc, 2475 const union sctp_subtype type, 2476 void *arg, 2477 struct sctp_cmd_seq *commands) 2478 { 2479 struct sctp_chunk *chunk = arg; 2480 2481 if (!sctp_vtag_verify_either(chunk, asoc)) 2482 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2483 2484 /* Make sure that the ABORT chunk has a valid length. 2485 * Since this is an ABORT chunk, we have to discard it 2486 * because of the following text: 2487 * RFC 2960, Section 3.3.7 2488 * If an endpoint receives an ABORT with a format error or for an 2489 * association that doesn't exist, it MUST silently discard it. 2490 * Because the length is "invalid", we can't really discard just 2491 * as we do not know its true length. So, to be safe, discard the 2492 * packet. 2493 */ 2494 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2495 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2496 2497 /* ADD-IP: Special case for ABORT chunks 2498 * F4) One special consideration is that ABORT Chunks arriving 2499 * destined to the IP address being deleted MUST be 2500 * ignored (see Section 5.3.1 for further details). 2501 */ 2502 if (SCTP_ADDR_DEL == 2503 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2504 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2505 2506 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2507 } 2508 2509 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2510 struct net *net, 2511 const struct sctp_endpoint *ep, 2512 const struct sctp_association *asoc, 2513 const union sctp_subtype type, 2514 void *arg, 2515 struct sctp_cmd_seq *commands) 2516 { 2517 __be16 error = SCTP_ERROR_NO_ERROR; 2518 struct sctp_chunk *chunk = arg; 2519 unsigned int len; 2520 2521 /* See if we have an error cause code in the chunk. */ 2522 len = ntohs(chunk->chunk_hdr->length); 2523 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2524 struct sctp_errhdr *err; 2525 2526 sctp_walk_errors(err, chunk->chunk_hdr); 2527 if ((void *)err != (void *)chunk->chunk_end) 2528 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 2529 commands); 2530 2531 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2532 } 2533 2534 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2535 /* ASSOC_FAILED will DELETE_TCB. */ 2536 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2537 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2538 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2539 2540 return SCTP_DISPOSITION_ABORT; 2541 } 2542 2543 /* 2544 * Process an ABORT. (COOKIE-WAIT state) 2545 * 2546 * See sctp_sf_do_9_1_abort() above. 2547 */ 2548 enum sctp_disposition sctp_sf_cookie_wait_abort( 2549 struct net *net, 2550 const struct sctp_endpoint *ep, 2551 const struct sctp_association *asoc, 2552 const union sctp_subtype type, 2553 void *arg, 2554 struct sctp_cmd_seq *commands) 2555 { 2556 __be16 error = SCTP_ERROR_NO_ERROR; 2557 struct sctp_chunk *chunk = arg; 2558 unsigned int len; 2559 2560 if (!sctp_vtag_verify_either(chunk, asoc)) 2561 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2562 2563 /* Make sure that the ABORT chunk has a valid length. 2564 * Since this is an ABORT chunk, we have to discard it 2565 * because of the following text: 2566 * RFC 2960, Section 3.3.7 2567 * If an endpoint receives an ABORT with a format error or for an 2568 * association that doesn't exist, it MUST silently discard it. 2569 * Because the length is "invalid", we can't really discard just 2570 * as we do not know its true length. So, to be safe, discard the 2571 * packet. 2572 */ 2573 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2574 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2575 2576 /* See if we have an error cause code in the chunk. */ 2577 len = ntohs(chunk->chunk_hdr->length); 2578 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2579 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2580 2581 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2582 chunk->transport); 2583 } 2584 2585 /* 2586 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2587 */ 2588 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2589 struct net *net, 2590 const struct sctp_endpoint *ep, 2591 const struct sctp_association *asoc, 2592 const union sctp_subtype type, 2593 void *arg, 2594 struct sctp_cmd_seq *commands) 2595 { 2596 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2597 ENOPROTOOPT, asoc, 2598 (struct sctp_transport *)arg); 2599 } 2600 2601 /* 2602 * Process an ABORT. (COOKIE-ECHOED state) 2603 */ 2604 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2605 struct net *net, 2606 const struct sctp_endpoint *ep, 2607 const struct sctp_association *asoc, 2608 const union sctp_subtype type, 2609 void *arg, 2610 struct sctp_cmd_seq *commands) 2611 { 2612 /* There is a single T1 timer, so we should be able to use 2613 * common function with the COOKIE-WAIT state. 2614 */ 2615 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2616 } 2617 2618 /* 2619 * Stop T1 timer and abort association with "INIT failed". 2620 * 2621 * This is common code called by several sctp_sf_*_abort() functions above. 2622 */ 2623 static enum sctp_disposition sctp_stop_t1_and_abort( 2624 struct net *net, 2625 struct sctp_cmd_seq *commands, 2626 __be16 error, int sk_err, 2627 const struct sctp_association *asoc, 2628 struct sctp_transport *transport) 2629 { 2630 pr_debug("%s: ABORT received (INIT)\n", __func__); 2631 2632 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2633 SCTP_STATE(SCTP_STATE_CLOSED)); 2634 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2635 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2636 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2637 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2638 /* CMD_INIT_FAILED will DELETE_TCB. */ 2639 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2640 SCTP_PERR(error)); 2641 2642 return SCTP_DISPOSITION_ABORT; 2643 } 2644 2645 /* 2646 * sctp_sf_do_9_2_shut 2647 * 2648 * Section: 9.2 2649 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2650 * - enter the SHUTDOWN-RECEIVED state, 2651 * 2652 * - stop accepting new data from its SCTP user 2653 * 2654 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2655 * that all its outstanding DATA chunks have been received by the 2656 * SHUTDOWN sender. 2657 * 2658 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2659 * send a SHUTDOWN in response to a ULP request. And should discard 2660 * subsequent SHUTDOWN chunks. 2661 * 2662 * If there are still outstanding DATA chunks left, the SHUTDOWN 2663 * receiver shall continue to follow normal data transmission 2664 * procedures defined in Section 6 until all outstanding DATA chunks 2665 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2666 * new data from its SCTP user. 2667 * 2668 * Verification Tag: 8.5 Verification Tag [Normal verification] 2669 * 2670 * Inputs 2671 * (endpoint, asoc, chunk) 2672 * 2673 * Outputs 2674 * (asoc, reply_msg, msg_up, timers, counters) 2675 * 2676 * The return value is the disposition of the chunk. 2677 */ 2678 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2679 struct net *net, 2680 const struct sctp_endpoint *ep, 2681 const struct sctp_association *asoc, 2682 const union sctp_subtype type, 2683 void *arg, 2684 struct sctp_cmd_seq *commands) 2685 { 2686 enum sctp_disposition disposition; 2687 struct sctp_chunk *chunk = arg; 2688 struct sctp_shutdownhdr *sdh; 2689 struct sctp_ulpevent *ev; 2690 __u32 ctsn; 2691 2692 if (!sctp_vtag_verify(chunk, asoc)) 2693 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2694 2695 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2696 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2697 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2698 commands); 2699 2700 /* Convert the elaborate header. */ 2701 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2702 skb_pull(chunk->skb, sizeof(*sdh)); 2703 chunk->subh.shutdown_hdr = sdh; 2704 ctsn = ntohl(sdh->cum_tsn_ack); 2705 2706 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2707 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2708 asoc->ctsn_ack_point); 2709 2710 return SCTP_DISPOSITION_DISCARD; 2711 } 2712 2713 /* If Cumulative TSN Ack beyond the max tsn currently 2714 * send, terminating the association and respond to the 2715 * sender with an ABORT. 2716 */ 2717 if (!TSN_lt(ctsn, asoc->next_tsn)) 2718 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2719 2720 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2721 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2722 * inform the application that it should cease sending data. 2723 */ 2724 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2725 if (!ev) { 2726 disposition = SCTP_DISPOSITION_NOMEM; 2727 goto out; 2728 } 2729 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2730 2731 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2732 * - enter the SHUTDOWN-RECEIVED state, 2733 * - stop accepting new data from its SCTP user 2734 * 2735 * [This is implicit in the new state.] 2736 */ 2737 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2738 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2739 disposition = SCTP_DISPOSITION_CONSUME; 2740 2741 if (sctp_outq_is_empty(&asoc->outqueue)) { 2742 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2743 arg, commands); 2744 } 2745 2746 if (SCTP_DISPOSITION_NOMEM == disposition) 2747 goto out; 2748 2749 /* - verify, by checking the Cumulative TSN Ack field of the 2750 * chunk, that all its outstanding DATA chunks have been 2751 * received by the SHUTDOWN sender. 2752 */ 2753 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2754 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2755 2756 out: 2757 return disposition; 2758 } 2759 2760 /* 2761 * sctp_sf_do_9_2_shut_ctsn 2762 * 2763 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2764 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2765 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2766 * MUST be processed. 2767 */ 2768 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2769 struct net *net, 2770 const struct sctp_endpoint *ep, 2771 const struct sctp_association *asoc, 2772 const union sctp_subtype type, 2773 void *arg, 2774 struct sctp_cmd_seq *commands) 2775 { 2776 struct sctp_chunk *chunk = arg; 2777 struct sctp_shutdownhdr *sdh; 2778 __u32 ctsn; 2779 2780 if (!sctp_vtag_verify(chunk, asoc)) 2781 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2782 2783 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2784 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2785 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2786 commands); 2787 2788 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2789 ctsn = ntohl(sdh->cum_tsn_ack); 2790 2791 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2792 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2793 asoc->ctsn_ack_point); 2794 2795 return SCTP_DISPOSITION_DISCARD; 2796 } 2797 2798 /* If Cumulative TSN Ack beyond the max tsn currently 2799 * send, terminating the association and respond to the 2800 * sender with an ABORT. 2801 */ 2802 if (!TSN_lt(ctsn, asoc->next_tsn)) 2803 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2804 2805 /* verify, by checking the Cumulative TSN Ack field of the 2806 * chunk, that all its outstanding DATA chunks have been 2807 * received by the SHUTDOWN sender. 2808 */ 2809 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2810 SCTP_BE32(sdh->cum_tsn_ack)); 2811 2812 return SCTP_DISPOSITION_CONSUME; 2813 } 2814 2815 /* RFC 2960 9.2 2816 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2817 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2818 * transport addresses (either in the IP addresses or in the INIT chunk) 2819 * that belong to this association, it should discard the INIT chunk and 2820 * retransmit the SHUTDOWN ACK chunk. 2821 */ 2822 enum sctp_disposition sctp_sf_do_9_2_reshutack( 2823 struct net *net, 2824 const struct sctp_endpoint *ep, 2825 const struct sctp_association *asoc, 2826 const union sctp_subtype type, 2827 void *arg, 2828 struct sctp_cmd_seq *commands) 2829 { 2830 struct sctp_chunk *chunk = arg; 2831 struct sctp_chunk *reply; 2832 2833 /* Make sure that the chunk has a valid length */ 2834 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2835 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2836 commands); 2837 2838 /* Since we are not going to really process this INIT, there 2839 * is no point in verifying chunk boundries. Just generate 2840 * the SHUTDOWN ACK. 2841 */ 2842 reply = sctp_make_shutdown_ack(asoc, chunk); 2843 if (NULL == reply) 2844 goto nomem; 2845 2846 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2847 * the T2-SHUTDOWN timer. 2848 */ 2849 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2850 2851 /* and restart the T2-shutdown timer. */ 2852 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2853 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2854 2855 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2856 2857 return SCTP_DISPOSITION_CONSUME; 2858 nomem: 2859 return SCTP_DISPOSITION_NOMEM; 2860 } 2861 2862 /* 2863 * sctp_sf_do_ecn_cwr 2864 * 2865 * Section: Appendix A: Explicit Congestion Notification 2866 * 2867 * CWR: 2868 * 2869 * RFC 2481 details a specific bit for a sender to send in the header of 2870 * its next outbound TCP segment to indicate to its peer that it has 2871 * reduced its congestion window. This is termed the CWR bit. For 2872 * SCTP the same indication is made by including the CWR chunk. 2873 * This chunk contains one data element, i.e. the TSN number that 2874 * was sent in the ECNE chunk. This element represents the lowest 2875 * TSN number in the datagram that was originally marked with the 2876 * CE bit. 2877 * 2878 * Verification Tag: 8.5 Verification Tag [Normal verification] 2879 * Inputs 2880 * (endpoint, asoc, chunk) 2881 * 2882 * Outputs 2883 * (asoc, reply_msg, msg_up, timers, counters) 2884 * 2885 * The return value is the disposition of the chunk. 2886 */ 2887 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 2888 const struct sctp_endpoint *ep, 2889 const struct sctp_association *asoc, 2890 const union sctp_subtype type, 2891 void *arg, 2892 struct sctp_cmd_seq *commands) 2893 { 2894 struct sctp_chunk *chunk = arg; 2895 struct sctp_cwrhdr *cwr; 2896 u32 lowest_tsn; 2897 2898 if (!sctp_vtag_verify(chunk, asoc)) 2899 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2900 2901 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 2902 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2903 commands); 2904 2905 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 2906 skb_pull(chunk->skb, sizeof(*cwr)); 2907 2908 lowest_tsn = ntohl(cwr->lowest_tsn); 2909 2910 /* Does this CWR ack the last sent congestion notification? */ 2911 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2912 /* Stop sending ECNE. */ 2913 sctp_add_cmd_sf(commands, 2914 SCTP_CMD_ECN_CWR, 2915 SCTP_U32(lowest_tsn)); 2916 } 2917 return SCTP_DISPOSITION_CONSUME; 2918 } 2919 2920 /* 2921 * sctp_sf_do_ecne 2922 * 2923 * Section: Appendix A: Explicit Congestion Notification 2924 * 2925 * ECN-Echo 2926 * 2927 * RFC 2481 details a specific bit for a receiver to send back in its 2928 * TCP acknowledgements to notify the sender of the Congestion 2929 * Experienced (CE) bit having arrived from the network. For SCTP this 2930 * same indication is made by including the ECNE chunk. This chunk 2931 * contains one data element, i.e. the lowest TSN associated with the IP 2932 * datagram marked with the CE bit..... 2933 * 2934 * Verification Tag: 8.5 Verification Tag [Normal verification] 2935 * Inputs 2936 * (endpoint, asoc, chunk) 2937 * 2938 * Outputs 2939 * (asoc, reply_msg, msg_up, timers, counters) 2940 * 2941 * The return value is the disposition of the chunk. 2942 */ 2943 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 2944 const struct sctp_endpoint *ep, 2945 const struct sctp_association *asoc, 2946 const union sctp_subtype type, 2947 void *arg, struct sctp_cmd_seq *commands) 2948 { 2949 struct sctp_chunk *chunk = arg; 2950 struct sctp_ecnehdr *ecne; 2951 2952 if (!sctp_vtag_verify(chunk, asoc)) 2953 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2954 2955 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 2956 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2957 commands); 2958 2959 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 2960 skb_pull(chunk->skb, sizeof(*ecne)); 2961 2962 /* If this is a newer ECNE than the last CWR packet we sent out */ 2963 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2964 SCTP_U32(ntohl(ecne->lowest_tsn))); 2965 2966 return SCTP_DISPOSITION_CONSUME; 2967 } 2968 2969 /* 2970 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2971 * 2972 * The SCTP endpoint MUST always acknowledge the reception of each valid 2973 * DATA chunk. 2974 * 2975 * The guidelines on delayed acknowledgement algorithm specified in 2976 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2977 * acknowledgement SHOULD be generated for at least every second packet 2978 * (not every second DATA chunk) received, and SHOULD be generated within 2979 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2980 * situations it may be beneficial for an SCTP transmitter to be more 2981 * conservative than the algorithms detailed in this document allow. 2982 * However, an SCTP transmitter MUST NOT be more aggressive than the 2983 * following algorithms allow. 2984 * 2985 * A SCTP receiver MUST NOT generate more than one SACK for every 2986 * incoming packet, other than to update the offered window as the 2987 * receiving application consumes new data. 2988 * 2989 * Verification Tag: 8.5 Verification Tag [Normal verification] 2990 * 2991 * Inputs 2992 * (endpoint, asoc, chunk) 2993 * 2994 * Outputs 2995 * (asoc, reply_msg, msg_up, timers, counters) 2996 * 2997 * The return value is the disposition of the chunk. 2998 */ 2999 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3000 const struct sctp_endpoint *ep, 3001 const struct sctp_association *asoc, 3002 const union sctp_subtype type, 3003 void *arg, 3004 struct sctp_cmd_seq *commands) 3005 { 3006 union sctp_arg force = SCTP_NOFORCE(); 3007 struct sctp_chunk *chunk = arg; 3008 int error; 3009 3010 if (!sctp_vtag_verify(chunk, asoc)) { 3011 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3012 SCTP_NULL()); 3013 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3014 } 3015 3016 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3017 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3018 commands); 3019 3020 error = sctp_eat_data(asoc, chunk, commands); 3021 switch (error) { 3022 case SCTP_IERROR_NO_ERROR: 3023 break; 3024 case SCTP_IERROR_HIGH_TSN: 3025 case SCTP_IERROR_BAD_STREAM: 3026 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3027 goto discard_noforce; 3028 case SCTP_IERROR_DUP_TSN: 3029 case SCTP_IERROR_IGNORE_TSN: 3030 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3031 goto discard_force; 3032 case SCTP_IERROR_NO_DATA: 3033 return SCTP_DISPOSITION_ABORT; 3034 case SCTP_IERROR_PROTO_VIOLATION: 3035 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3036 (u8 *)chunk->subh.data_hdr, 3037 sctp_datahdr_len(&asoc->stream)); 3038 default: 3039 BUG(); 3040 } 3041 3042 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3043 force = SCTP_FORCE(); 3044 3045 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3046 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3047 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3048 } 3049 3050 /* If this is the last chunk in a packet, we need to count it 3051 * toward sack generation. Note that we need to SACK every 3052 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3053 * THEM. We elect to NOT generate SACK's if the chunk fails 3054 * the verification tag test. 3055 * 3056 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3057 * 3058 * The SCTP endpoint MUST always acknowledge the reception of 3059 * each valid DATA chunk. 3060 * 3061 * The guidelines on delayed acknowledgement algorithm 3062 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3063 * Specifically, an acknowledgement SHOULD be generated for at 3064 * least every second packet (not every second DATA chunk) 3065 * received, and SHOULD be generated within 200 ms of the 3066 * arrival of any unacknowledged DATA chunk. In some 3067 * situations it may be beneficial for an SCTP transmitter to 3068 * be more conservative than the algorithms detailed in this 3069 * document allow. However, an SCTP transmitter MUST NOT be 3070 * more aggressive than the following algorithms allow. 3071 */ 3072 if (chunk->end_of_packet) 3073 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3074 3075 return SCTP_DISPOSITION_CONSUME; 3076 3077 discard_force: 3078 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3079 * 3080 * When a packet arrives with duplicate DATA chunk(s) and with 3081 * no new DATA chunk(s), the endpoint MUST immediately send a 3082 * SACK with no delay. If a packet arrives with duplicate 3083 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3084 * MAY immediately send a SACK. Normally receipt of duplicate 3085 * DATA chunks will occur when the original SACK chunk was lost 3086 * and the peer's RTO has expired. The duplicate TSN number(s) 3087 * SHOULD be reported in the SACK as duplicate. 3088 */ 3089 /* In our case, we split the MAY SACK advice up whether or not 3090 * the last chunk is a duplicate.' 3091 */ 3092 if (chunk->end_of_packet) 3093 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3094 return SCTP_DISPOSITION_DISCARD; 3095 3096 discard_noforce: 3097 if (chunk->end_of_packet) 3098 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3099 3100 return SCTP_DISPOSITION_DISCARD; 3101 } 3102 3103 /* 3104 * sctp_sf_eat_data_fast_4_4 3105 * 3106 * Section: 4 (4) 3107 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3108 * DATA chunks without delay. 3109 * 3110 * Verification Tag: 8.5 Verification Tag [Normal verification] 3111 * Inputs 3112 * (endpoint, asoc, chunk) 3113 * 3114 * Outputs 3115 * (asoc, reply_msg, msg_up, timers, counters) 3116 * 3117 * The return value is the disposition of the chunk. 3118 */ 3119 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3120 struct net *net, 3121 const struct sctp_endpoint *ep, 3122 const struct sctp_association *asoc, 3123 const union sctp_subtype type, 3124 void *arg, 3125 struct sctp_cmd_seq *commands) 3126 { 3127 struct sctp_chunk *chunk = arg; 3128 int error; 3129 3130 if (!sctp_vtag_verify(chunk, asoc)) { 3131 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3132 SCTP_NULL()); 3133 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3134 } 3135 3136 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3137 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3138 commands); 3139 3140 error = sctp_eat_data(asoc, chunk, commands); 3141 switch (error) { 3142 case SCTP_IERROR_NO_ERROR: 3143 case SCTP_IERROR_HIGH_TSN: 3144 case SCTP_IERROR_DUP_TSN: 3145 case SCTP_IERROR_IGNORE_TSN: 3146 case SCTP_IERROR_BAD_STREAM: 3147 break; 3148 case SCTP_IERROR_NO_DATA: 3149 return SCTP_DISPOSITION_ABORT; 3150 case SCTP_IERROR_PROTO_VIOLATION: 3151 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3152 (u8 *)chunk->subh.data_hdr, 3153 sctp_datahdr_len(&asoc->stream)); 3154 default: 3155 BUG(); 3156 } 3157 3158 /* Go a head and force a SACK, since we are shutting down. */ 3159 3160 /* Implementor's Guide. 3161 * 3162 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3163 * respond to each received packet containing one or more DATA chunk(s) 3164 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3165 */ 3166 if (chunk->end_of_packet) { 3167 /* We must delay the chunk creation since the cumulative 3168 * TSN has not been updated yet. 3169 */ 3170 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3171 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3172 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3173 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3174 } 3175 3176 return SCTP_DISPOSITION_CONSUME; 3177 } 3178 3179 /* 3180 * Section: 6.2 Processing a Received SACK 3181 * D) Any time a SACK arrives, the endpoint performs the following: 3182 * 3183 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3184 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3185 * increasing, a SACK whose Cumulative TSN Ack is less than the 3186 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3187 * 3188 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3189 * of bytes still outstanding after processing the Cumulative TSN Ack 3190 * and the Gap Ack Blocks. 3191 * 3192 * iii) If the SACK is missing a TSN that was previously 3193 * acknowledged via a Gap Ack Block (e.g., the data receiver 3194 * reneged on the data), then mark the corresponding DATA chunk 3195 * as available for retransmit: Mark it as missing for fast 3196 * retransmit as described in Section 7.2.4 and if no retransmit 3197 * timer is running for the destination address to which the DATA 3198 * chunk was originally transmitted, then T3-rtx is started for 3199 * that destination address. 3200 * 3201 * Verification Tag: 8.5 Verification Tag [Normal verification] 3202 * 3203 * Inputs 3204 * (endpoint, asoc, chunk) 3205 * 3206 * Outputs 3207 * (asoc, reply_msg, msg_up, timers, counters) 3208 * 3209 * The return value is the disposition of the chunk. 3210 */ 3211 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3212 const struct sctp_endpoint *ep, 3213 const struct sctp_association *asoc, 3214 const union sctp_subtype type, 3215 void *arg, 3216 struct sctp_cmd_seq *commands) 3217 { 3218 struct sctp_chunk *chunk = arg; 3219 struct sctp_sackhdr *sackh; 3220 __u32 ctsn; 3221 3222 if (!sctp_vtag_verify(chunk, asoc)) 3223 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3224 3225 /* Make sure that the SACK chunk has a valid length. */ 3226 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3227 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3228 commands); 3229 3230 /* Pull the SACK chunk from the data buffer */ 3231 sackh = sctp_sm_pull_sack(chunk); 3232 /* Was this a bogus SACK? */ 3233 if (!sackh) 3234 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3235 chunk->subh.sack_hdr = sackh; 3236 ctsn = ntohl(sackh->cum_tsn_ack); 3237 3238 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3239 * Ack Point, then drop the SACK. Since Cumulative TSN 3240 * Ack is monotonically increasing, a SACK whose 3241 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3242 * Point indicates an out-of-order SACK. 3243 */ 3244 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3245 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3246 asoc->ctsn_ack_point); 3247 3248 return SCTP_DISPOSITION_DISCARD; 3249 } 3250 3251 /* If Cumulative TSN Ack beyond the max tsn currently 3252 * send, terminating the association and respond to the 3253 * sender with an ABORT. 3254 */ 3255 if (!TSN_lt(ctsn, asoc->next_tsn)) 3256 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3257 3258 /* Return this SACK for further processing. */ 3259 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3260 3261 /* Note: We do the rest of the work on the PROCESS_SACK 3262 * sideeffect. 3263 */ 3264 return SCTP_DISPOSITION_CONSUME; 3265 } 3266 3267 /* 3268 * Generate an ABORT in response to a packet. 3269 * 3270 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3271 * 3272 * 8) The receiver should respond to the sender of the OOTB packet with 3273 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3274 * MUST fill in the Verification Tag field of the outbound packet 3275 * with the value found in the Verification Tag field of the OOTB 3276 * packet and set the T-bit in the Chunk Flags to indicate that the 3277 * Verification Tag is reflected. After sending this ABORT, the 3278 * receiver of the OOTB packet shall discard the OOTB packet and take 3279 * no further action. 3280 * 3281 * Verification Tag: 3282 * 3283 * The return value is the disposition of the chunk. 3284 */ 3285 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3286 struct net *net, 3287 const struct sctp_endpoint *ep, 3288 const struct sctp_association *asoc, 3289 const union sctp_subtype type, 3290 void *arg, 3291 struct sctp_cmd_seq *commands) 3292 { 3293 struct sctp_packet *packet = NULL; 3294 struct sctp_chunk *chunk = arg; 3295 struct sctp_chunk *abort; 3296 3297 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3298 if (!packet) 3299 return SCTP_DISPOSITION_NOMEM; 3300 3301 /* Make an ABORT. The T bit will be set if the asoc 3302 * is NULL. 3303 */ 3304 abort = sctp_make_abort(asoc, chunk, 0); 3305 if (!abort) { 3306 sctp_ootb_pkt_free(packet); 3307 return SCTP_DISPOSITION_NOMEM; 3308 } 3309 3310 /* Reflect vtag if T-Bit is set */ 3311 if (sctp_test_T_bit(abort)) 3312 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3313 3314 /* Set the skb to the belonging sock for accounting. */ 3315 abort->skb->sk = ep->base.sk; 3316 3317 sctp_packet_append_chunk(packet, abort); 3318 3319 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3320 SCTP_PACKET(packet)); 3321 3322 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3323 3324 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3325 return SCTP_DISPOSITION_CONSUME; 3326 } 3327 3328 /* 3329 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3330 * event as ULP notification for each cause included in the chunk. 3331 * 3332 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3333 * 3334 * The return value is the disposition of the chunk. 3335 */ 3336 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3337 const struct sctp_endpoint *ep, 3338 const struct sctp_association *asoc, 3339 const union sctp_subtype type, 3340 void *arg, 3341 struct sctp_cmd_seq *commands) 3342 { 3343 struct sctp_chunk *chunk = arg; 3344 struct sctp_errhdr *err; 3345 3346 if (!sctp_vtag_verify(chunk, asoc)) 3347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3348 3349 /* Make sure that the ERROR chunk has a valid length. */ 3350 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3351 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3352 commands); 3353 sctp_walk_errors(err, chunk->chunk_hdr); 3354 if ((void *)err != (void *)chunk->chunk_end) 3355 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3356 (void *)err, commands); 3357 3358 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3359 SCTP_CHUNK(chunk)); 3360 3361 return SCTP_DISPOSITION_CONSUME; 3362 } 3363 3364 /* 3365 * Process an inbound SHUTDOWN ACK. 3366 * 3367 * From Section 9.2: 3368 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3369 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3370 * peer, and remove all record of the association. 3371 * 3372 * The return value is the disposition. 3373 */ 3374 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3375 const struct sctp_endpoint *ep, 3376 const struct sctp_association *asoc, 3377 const union sctp_subtype type, 3378 void *arg, 3379 struct sctp_cmd_seq *commands) 3380 { 3381 struct sctp_chunk *chunk = arg; 3382 struct sctp_chunk *reply; 3383 struct sctp_ulpevent *ev; 3384 3385 if (!sctp_vtag_verify(chunk, asoc)) 3386 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3387 3388 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3389 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3390 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3391 commands); 3392 /* 10.2 H) SHUTDOWN COMPLETE notification 3393 * 3394 * When SCTP completes the shutdown procedures (section 9.2) this 3395 * notification is passed to the upper layer. 3396 */ 3397 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3398 0, 0, 0, NULL, GFP_ATOMIC); 3399 if (!ev) 3400 goto nomem; 3401 3402 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3403 reply = sctp_make_shutdown_complete(asoc, chunk); 3404 if (!reply) 3405 goto nomem_chunk; 3406 3407 /* Do all the commands now (after allocation), so that we 3408 * have consistent state if memory allocation failes 3409 */ 3410 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3411 3412 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3413 * stop the T2-shutdown timer, 3414 */ 3415 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3416 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3417 3418 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3419 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3420 3421 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3422 SCTP_STATE(SCTP_STATE_CLOSED)); 3423 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3424 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3425 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3426 3427 /* ...and remove all record of the association. */ 3428 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3429 return SCTP_DISPOSITION_DELETE_TCB; 3430 3431 nomem_chunk: 3432 sctp_ulpevent_free(ev); 3433 nomem: 3434 return SCTP_DISPOSITION_NOMEM; 3435 } 3436 3437 /* 3438 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3439 * 3440 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3441 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3442 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3443 * packet must fill in the Verification Tag field of the outbound 3444 * packet with the Verification Tag received in the SHUTDOWN ACK and 3445 * set the T-bit in the Chunk Flags to indicate that the Verification 3446 * Tag is reflected. 3447 * 3448 * 8) The receiver should respond to the sender of the OOTB packet with 3449 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3450 * MUST fill in the Verification Tag field of the outbound packet 3451 * with the value found in the Verification Tag field of the OOTB 3452 * packet and set the T-bit in the Chunk Flags to indicate that the 3453 * Verification Tag is reflected. After sending this ABORT, the 3454 * receiver of the OOTB packet shall discard the OOTB packet and take 3455 * no further action. 3456 */ 3457 enum sctp_disposition sctp_sf_ootb(struct net *net, 3458 const struct sctp_endpoint *ep, 3459 const struct sctp_association *asoc, 3460 const union sctp_subtype type, 3461 void *arg, struct sctp_cmd_seq *commands) 3462 { 3463 struct sctp_chunk *chunk = arg; 3464 struct sk_buff *skb = chunk->skb; 3465 struct sctp_chunkhdr *ch; 3466 struct sctp_errhdr *err; 3467 int ootb_cookie_ack = 0; 3468 int ootb_shut_ack = 0; 3469 __u8 *ch_end; 3470 3471 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3472 3473 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3474 do { 3475 /* Report violation if the chunk is less then minimal */ 3476 if (ntohs(ch->length) < sizeof(*ch)) 3477 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3478 commands); 3479 3480 /* Report violation if chunk len overflows */ 3481 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3482 if (ch_end > skb_tail_pointer(skb)) 3483 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3484 commands); 3485 3486 /* Now that we know we at least have a chunk header, 3487 * do things that are type appropriate. 3488 */ 3489 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3490 ootb_shut_ack = 1; 3491 3492 /* RFC 2960, Section 3.3.7 3493 * Moreover, under any circumstances, an endpoint that 3494 * receives an ABORT MUST NOT respond to that ABORT by 3495 * sending an ABORT of its own. 3496 */ 3497 if (SCTP_CID_ABORT == ch->type) 3498 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3499 3500 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3501 * or a COOKIE ACK the SCTP Packet should be silently 3502 * discarded. 3503 */ 3504 3505 if (SCTP_CID_COOKIE_ACK == ch->type) 3506 ootb_cookie_ack = 1; 3507 3508 if (SCTP_CID_ERROR == ch->type) { 3509 sctp_walk_errors(err, ch) { 3510 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3511 ootb_cookie_ack = 1; 3512 break; 3513 } 3514 } 3515 } 3516 3517 ch = (struct sctp_chunkhdr *)ch_end; 3518 } while (ch_end < skb_tail_pointer(skb)); 3519 3520 if (ootb_shut_ack) 3521 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3522 else if (ootb_cookie_ack) 3523 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3524 else 3525 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3526 } 3527 3528 /* 3529 * Handle an "Out of the blue" SHUTDOWN ACK. 3530 * 3531 * Section: 8.4 5, sctpimpguide 2.41. 3532 * 3533 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3534 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3535 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3536 * packet must fill in the Verification Tag field of the outbound 3537 * packet with the Verification Tag received in the SHUTDOWN ACK and 3538 * set the T-bit in the Chunk Flags to indicate that the Verification 3539 * Tag is reflected. 3540 * 3541 * Inputs 3542 * (endpoint, asoc, type, arg, commands) 3543 * 3544 * Outputs 3545 * (enum sctp_disposition) 3546 * 3547 * The return value is the disposition of the chunk. 3548 */ 3549 static enum sctp_disposition sctp_sf_shut_8_4_5( 3550 struct net *net, 3551 const struct sctp_endpoint *ep, 3552 const struct sctp_association *asoc, 3553 const union sctp_subtype type, 3554 void *arg, 3555 struct sctp_cmd_seq *commands) 3556 { 3557 struct sctp_packet *packet = NULL; 3558 struct sctp_chunk *chunk = arg; 3559 struct sctp_chunk *shut; 3560 3561 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3562 if (!packet) 3563 return SCTP_DISPOSITION_NOMEM; 3564 3565 /* Make an SHUTDOWN_COMPLETE. 3566 * The T bit will be set if the asoc is NULL. 3567 */ 3568 shut = sctp_make_shutdown_complete(asoc, chunk); 3569 if (!shut) { 3570 sctp_ootb_pkt_free(packet); 3571 return SCTP_DISPOSITION_NOMEM; 3572 } 3573 3574 /* Reflect vtag if T-Bit is set */ 3575 if (sctp_test_T_bit(shut)) 3576 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3577 3578 /* Set the skb to the belonging sock for accounting. */ 3579 shut->skb->sk = ep->base.sk; 3580 3581 sctp_packet_append_chunk(packet, shut); 3582 3583 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3584 SCTP_PACKET(packet)); 3585 3586 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3587 3588 /* If the chunk length is invalid, we don't want to process 3589 * the reset of the packet. 3590 */ 3591 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3592 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3593 3594 /* We need to discard the rest of the packet to prevent 3595 * potential bomming attacks from additional bundled chunks. 3596 * This is documented in SCTP Threats ID. 3597 */ 3598 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3599 } 3600 3601 /* 3602 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3603 * 3604 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3605 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3606 * procedures in section 8.4 SHOULD be followed, in other words it 3607 * should be treated as an Out Of The Blue packet. 3608 * [This means that we do NOT check the Verification Tag on these 3609 * chunks. --piggy ] 3610 * 3611 */ 3612 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3613 const struct sctp_endpoint *ep, 3614 const struct sctp_association *asoc, 3615 const union sctp_subtype type, 3616 void *arg, 3617 struct sctp_cmd_seq *commands) 3618 { 3619 struct sctp_chunk *chunk = arg; 3620 3621 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3622 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3623 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3624 commands); 3625 3626 /* Although we do have an association in this case, it corresponds 3627 * to a restarted association. So the packet is treated as an OOTB 3628 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3629 * called with a NULL association. 3630 */ 3631 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3632 3633 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3634 } 3635 3636 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3637 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3638 const struct sctp_endpoint *ep, 3639 const struct sctp_association *asoc, 3640 const union sctp_subtype type, 3641 void *arg, 3642 struct sctp_cmd_seq *commands) 3643 { 3644 struct sctp_paramhdr *err_param = NULL; 3645 struct sctp_chunk *asconf_ack = NULL; 3646 struct sctp_chunk *chunk = arg; 3647 struct sctp_addiphdr *hdr; 3648 __u32 serial; 3649 3650 if (!sctp_vtag_verify(chunk, asoc)) { 3651 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3652 SCTP_NULL()); 3653 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3654 } 3655 3656 /* ADD-IP: Section 4.1.1 3657 * This chunk MUST be sent in an authenticated way by using 3658 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3659 * is received unauthenticated it MUST be silently discarded as 3660 * described in [I-D.ietf-tsvwg-sctp-auth]. 3661 */ 3662 if (!net->sctp.addip_noauth && !chunk->auth) 3663 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3664 commands); 3665 3666 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3667 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3668 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3669 commands); 3670 3671 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3672 serial = ntohl(hdr->serial); 3673 3674 /* Verify the ASCONF chunk before processing it. */ 3675 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3676 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3677 (void *)err_param, commands); 3678 3679 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3680 * the endpoint stored in a new association variable 3681 * 'Peer-Serial-Number'. 3682 */ 3683 if (serial == asoc->peer.addip_serial + 1) { 3684 /* If this is the first instance of ASCONF in the packet, 3685 * we can clean our old ASCONF-ACKs. 3686 */ 3687 if (!chunk->has_asconf) 3688 sctp_assoc_clean_asconf_ack_cache(asoc); 3689 3690 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3691 * expected, process the ASCONF as described below and after 3692 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3693 * the response packet and cache a copy of it (in the event it 3694 * later needs to be retransmitted). 3695 * 3696 * Essentially, do V1-V5. 3697 */ 3698 asconf_ack = sctp_process_asconf((struct sctp_association *) 3699 asoc, chunk); 3700 if (!asconf_ack) 3701 return SCTP_DISPOSITION_NOMEM; 3702 } else if (serial < asoc->peer.addip_serial + 1) { 3703 /* ADDIP 5.2 E2) 3704 * If the value found in the Sequence Number is less than the 3705 * ('Peer- Sequence-Number' + 1), simply skip to the next 3706 * ASCONF, and include in the outbound response packet 3707 * any previously cached ASCONF-ACK response that was 3708 * sent and saved that matches the Sequence Number of the 3709 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3710 * Chunk exists. This will occur when an older ASCONF 3711 * arrives out of order. In such a case, the receiver 3712 * should skip the ASCONF Chunk and not include ASCONF-ACK 3713 * Chunk for that chunk. 3714 */ 3715 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3716 if (!asconf_ack) 3717 return SCTP_DISPOSITION_DISCARD; 3718 3719 /* Reset the transport so that we select the correct one 3720 * this time around. This is to make sure that we don't 3721 * accidentally use a stale transport that's been removed. 3722 */ 3723 asconf_ack->transport = NULL; 3724 } else { 3725 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3726 * it must be either a stale packet or from an attacker. 3727 */ 3728 return SCTP_DISPOSITION_DISCARD; 3729 } 3730 3731 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3732 * containing the ASCONF-ACK Chunks MUST be the source address of 3733 * the SCTP packet that held the ASCONF Chunks. 3734 * 3735 * To do this properly, we'll set the destination address of the chunk 3736 * and at the transmit time, will try look up the transport to use. 3737 * Since ASCONFs may be bundled, the correct transport may not be 3738 * created until we process the entire packet, thus this workaround. 3739 */ 3740 asconf_ack->dest = chunk->source; 3741 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3742 if (asoc->new_transport) { 3743 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3744 ((struct sctp_association *)asoc)->new_transport = NULL; 3745 } 3746 3747 return SCTP_DISPOSITION_CONSUME; 3748 } 3749 3750 /* 3751 * ADDIP Section 4.3 General rules for address manipulation 3752 * When building TLV parameters for the ASCONF Chunk that will add or 3753 * delete IP addresses the D0 to D13 rules should be applied: 3754 */ 3755 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 3756 const struct sctp_endpoint *ep, 3757 const struct sctp_association *asoc, 3758 const union sctp_subtype type, 3759 void *arg, 3760 struct sctp_cmd_seq *commands) 3761 { 3762 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3763 struct sctp_paramhdr *err_param = NULL; 3764 struct sctp_chunk *asconf_ack = arg; 3765 struct sctp_addiphdr *addip_hdr; 3766 __u32 sent_serial, rcvd_serial; 3767 struct sctp_chunk *abort; 3768 3769 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3770 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3771 SCTP_NULL()); 3772 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3773 } 3774 3775 /* ADD-IP, Section 4.1.2: 3776 * This chunk MUST be sent in an authenticated way by using 3777 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3778 * is received unauthenticated it MUST be silently discarded as 3779 * described in [I-D.ietf-tsvwg-sctp-auth]. 3780 */ 3781 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3782 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3783 commands); 3784 3785 /* Make sure that the ADDIP chunk has a valid length. */ 3786 if (!sctp_chunk_length_valid(asconf_ack, 3787 sizeof(struct sctp_addip_chunk))) 3788 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3789 commands); 3790 3791 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 3792 rcvd_serial = ntohl(addip_hdr->serial); 3793 3794 /* Verify the ASCONF-ACK chunk before processing it. */ 3795 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3796 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3797 (void *)err_param, commands); 3798 3799 if (last_asconf) { 3800 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr; 3801 sent_serial = ntohl(addip_hdr->serial); 3802 } else { 3803 sent_serial = asoc->addip_serial - 1; 3804 } 3805 3806 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3807 * equal to the next serial number to be used but no ASCONF chunk is 3808 * outstanding the endpoint MUST ABORT the association. Note that a 3809 * sequence number is greater than if it is no more than 2^^31-1 3810 * larger than the current sequence number (using serial arithmetic). 3811 */ 3812 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3813 !(asoc->addip_last_asconf)) { 3814 abort = sctp_make_abort(asoc, asconf_ack, 3815 sizeof(struct sctp_errhdr)); 3816 if (abort) { 3817 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3818 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3819 SCTP_CHUNK(abort)); 3820 } 3821 /* We are going to ABORT, so we might as well stop 3822 * processing the rest of the chunks in the packet. 3823 */ 3824 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3825 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3826 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3827 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3828 SCTP_ERROR(ECONNABORTED)); 3829 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3830 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3831 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3832 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3833 return SCTP_DISPOSITION_ABORT; 3834 } 3835 3836 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3837 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3838 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3839 3840 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3841 asconf_ack)) { 3842 /* Successfully processed ASCONF_ACK. We can 3843 * release the next asconf if we have one. 3844 */ 3845 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3846 SCTP_NULL()); 3847 return SCTP_DISPOSITION_CONSUME; 3848 } 3849 3850 abort = sctp_make_abort(asoc, asconf_ack, 3851 sizeof(struct sctp_errhdr)); 3852 if (abort) { 3853 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3854 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3855 SCTP_CHUNK(abort)); 3856 } 3857 /* We are going to ABORT, so we might as well stop 3858 * processing the rest of the chunks in the packet. 3859 */ 3860 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3861 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3862 SCTP_ERROR(ECONNABORTED)); 3863 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3864 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3865 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3866 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3867 return SCTP_DISPOSITION_ABORT; 3868 } 3869 3870 return SCTP_DISPOSITION_DISCARD; 3871 } 3872 3873 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 3874 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 3875 const struct sctp_endpoint *ep, 3876 const struct sctp_association *asoc, 3877 const union sctp_subtype type, 3878 void *arg, 3879 struct sctp_cmd_seq *commands) 3880 { 3881 struct sctp_paramhdr *err_param = NULL; 3882 struct sctp_chunk *chunk = arg; 3883 struct sctp_reconf_chunk *hdr; 3884 union sctp_params param; 3885 3886 if (!sctp_vtag_verify(chunk, asoc)) { 3887 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3888 SCTP_NULL()); 3889 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3890 } 3891 3892 /* Make sure that the RECONF chunk has a valid length. */ 3893 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 3894 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3895 commands); 3896 3897 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 3898 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3899 (void *)err_param, commands); 3900 3901 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 3902 sctp_walk_params(param, hdr, params) { 3903 struct sctp_chunk *reply = NULL; 3904 struct sctp_ulpevent *ev = NULL; 3905 3906 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 3907 reply = sctp_process_strreset_outreq( 3908 (struct sctp_association *)asoc, param, &ev); 3909 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 3910 reply = sctp_process_strreset_inreq( 3911 (struct sctp_association *)asoc, param, &ev); 3912 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 3913 reply = sctp_process_strreset_tsnreq( 3914 (struct sctp_association *)asoc, param, &ev); 3915 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 3916 reply = sctp_process_strreset_addstrm_out( 3917 (struct sctp_association *)asoc, param, &ev); 3918 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 3919 reply = sctp_process_strreset_addstrm_in( 3920 (struct sctp_association *)asoc, param, &ev); 3921 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 3922 reply = sctp_process_strreset_resp( 3923 (struct sctp_association *)asoc, param, &ev); 3924 3925 if (ev) 3926 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3927 SCTP_ULPEVENT(ev)); 3928 3929 if (reply) 3930 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3931 SCTP_CHUNK(reply)); 3932 } 3933 3934 return SCTP_DISPOSITION_CONSUME; 3935 } 3936 3937 /* 3938 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3939 * 3940 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3941 * its cumulative TSN point to the value carried in the FORWARD TSN 3942 * chunk, and then MUST further advance its cumulative TSN point locally 3943 * if possible. 3944 * After the above processing, the data receiver MUST stop reporting any 3945 * missing TSNs earlier than or equal to the new cumulative TSN point. 3946 * 3947 * Verification Tag: 8.5 Verification Tag [Normal verification] 3948 * 3949 * The return value is the disposition of the chunk. 3950 */ 3951 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 3952 const struct sctp_endpoint *ep, 3953 const struct sctp_association *asoc, 3954 const union sctp_subtype type, 3955 void *arg, 3956 struct sctp_cmd_seq *commands) 3957 { 3958 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3959 struct sctp_chunk *chunk = arg; 3960 __u16 len; 3961 __u32 tsn; 3962 3963 if (!sctp_vtag_verify(chunk, asoc)) { 3964 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3965 SCTP_NULL()); 3966 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3967 } 3968 3969 if (!asoc->peer.prsctp_capable) 3970 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 3971 3972 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3973 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 3974 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3975 commands); 3976 3977 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3978 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3979 len = ntohs(chunk->chunk_hdr->length); 3980 len -= sizeof(struct sctp_chunkhdr); 3981 skb_pull(chunk->skb, len); 3982 3983 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3984 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3985 3986 /* The TSN is too high--silently discard the chunk and count on it 3987 * getting retransmitted later. 3988 */ 3989 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3990 goto discard_noforce; 3991 3992 if (!asoc->stream.si->validate_ftsn(chunk)) 3993 goto discard_noforce; 3994 3995 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3996 if (len > sctp_ftsnhdr_len(&asoc->stream)) 3997 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3998 SCTP_CHUNK(chunk)); 3999 4000 /* Count this as receiving DATA. */ 4001 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4002 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4003 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4004 } 4005 4006 /* FIXME: For now send a SACK, but DATA processing may 4007 * send another. 4008 */ 4009 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4010 4011 return SCTP_DISPOSITION_CONSUME; 4012 4013 discard_noforce: 4014 return SCTP_DISPOSITION_DISCARD; 4015 } 4016 4017 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4018 struct net *net, 4019 const struct sctp_endpoint *ep, 4020 const struct sctp_association *asoc, 4021 const union sctp_subtype type, 4022 void *arg, 4023 struct sctp_cmd_seq *commands) 4024 { 4025 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4026 struct sctp_chunk *chunk = arg; 4027 __u16 len; 4028 __u32 tsn; 4029 4030 if (!sctp_vtag_verify(chunk, asoc)) { 4031 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4032 SCTP_NULL()); 4033 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4034 } 4035 4036 if (!asoc->peer.prsctp_capable) 4037 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4038 4039 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4040 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4041 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4042 commands); 4043 4044 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4045 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4046 len = ntohs(chunk->chunk_hdr->length); 4047 len -= sizeof(struct sctp_chunkhdr); 4048 skb_pull(chunk->skb, len); 4049 4050 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4051 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4052 4053 /* The TSN is too high--silently discard the chunk and count on it 4054 * getting retransmitted later. 4055 */ 4056 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4057 goto gen_shutdown; 4058 4059 if (!asoc->stream.si->validate_ftsn(chunk)) 4060 goto gen_shutdown; 4061 4062 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4063 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4064 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4065 SCTP_CHUNK(chunk)); 4066 4067 /* Go a head and force a SACK, since we are shutting down. */ 4068 gen_shutdown: 4069 /* Implementor's Guide. 4070 * 4071 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4072 * respond to each received packet containing one or more DATA chunk(s) 4073 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4074 */ 4075 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4076 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4077 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4078 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4079 4080 return SCTP_DISPOSITION_CONSUME; 4081 } 4082 4083 /* 4084 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4085 * 4086 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4087 * Identifier field. If this algorithm was not specified by the 4088 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4089 * during association setup, the AUTH chunk and all chunks after it MUST 4090 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4091 * defined in Section 4.1. 4092 * 4093 * If an endpoint with no shared key receives a Shared Key Identifier 4094 * other than 0, it MUST silently discard all authenticated chunks. If 4095 * the endpoint has at least one endpoint pair shared key for the peer, 4096 * it MUST use the key specified by the Shared Key Identifier if a 4097 * key has been configured for that Shared Key Identifier. If no 4098 * endpoint pair shared key has been configured for that Shared Key 4099 * Identifier, all authenticated chunks MUST be silently discarded. 4100 * 4101 * Verification Tag: 8.5 Verification Tag [Normal verification] 4102 * 4103 * The return value is the disposition of the chunk. 4104 */ 4105 static enum sctp_ierror sctp_sf_authenticate( 4106 struct net *net, 4107 const struct sctp_endpoint *ep, 4108 const struct sctp_association *asoc, 4109 const union sctp_subtype type, 4110 struct sctp_chunk *chunk) 4111 { 4112 struct sctp_authhdr *auth_hdr; 4113 __u8 *save_digest, *digest; 4114 struct sctp_hmac *hmac; 4115 unsigned int sig_len; 4116 __u16 key_id; 4117 4118 /* Pull in the auth header, so we can do some more verification */ 4119 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4120 chunk->subh.auth_hdr = auth_hdr; 4121 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4122 4123 /* Make sure that we support the HMAC algorithm from the auth 4124 * chunk. 4125 */ 4126 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4127 return SCTP_IERROR_AUTH_BAD_HMAC; 4128 4129 /* Make sure that the provided shared key identifier has been 4130 * configured 4131 */ 4132 key_id = ntohs(auth_hdr->shkey_id); 4133 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4134 return SCTP_IERROR_AUTH_BAD_KEYID; 4135 4136 4137 /* Make sure that the length of the signature matches what 4138 * we expect. 4139 */ 4140 sig_len = ntohs(chunk->chunk_hdr->length) - 4141 sizeof(struct sctp_auth_chunk); 4142 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4143 if (sig_len != hmac->hmac_len) 4144 return SCTP_IERROR_PROTO_VIOLATION; 4145 4146 /* Now that we've done validation checks, we can compute and 4147 * verify the hmac. The steps involved are: 4148 * 1. Save the digest from the chunk. 4149 * 2. Zero out the digest in the chunk. 4150 * 3. Compute the new digest 4151 * 4. Compare saved and new digests. 4152 */ 4153 digest = auth_hdr->hmac; 4154 skb_pull(chunk->skb, sig_len); 4155 4156 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4157 if (!save_digest) 4158 goto nomem; 4159 4160 memset(digest, 0, sig_len); 4161 4162 sctp_auth_calculate_hmac(asoc, chunk->skb, 4163 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4164 GFP_ATOMIC); 4165 4166 /* Discard the packet if the digests do not match */ 4167 if (memcmp(save_digest, digest, sig_len)) { 4168 kfree(save_digest); 4169 return SCTP_IERROR_BAD_SIG; 4170 } 4171 4172 kfree(save_digest); 4173 chunk->auth = 1; 4174 4175 return SCTP_IERROR_NO_ERROR; 4176 nomem: 4177 return SCTP_IERROR_NOMEM; 4178 } 4179 4180 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4181 const struct sctp_endpoint *ep, 4182 const struct sctp_association *asoc, 4183 const union sctp_subtype type, 4184 void *arg, struct sctp_cmd_seq *commands) 4185 { 4186 struct sctp_chunk *chunk = arg; 4187 struct sctp_authhdr *auth_hdr; 4188 struct sctp_chunk *err_chunk; 4189 enum sctp_ierror error; 4190 4191 /* Make sure that the peer has AUTH capable */ 4192 if (!asoc->peer.auth_capable) 4193 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4194 4195 if (!sctp_vtag_verify(chunk, asoc)) { 4196 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4197 SCTP_NULL()); 4198 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4199 } 4200 4201 /* Make sure that the AUTH chunk has valid length. */ 4202 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4203 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4204 commands); 4205 4206 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4207 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4208 switch (error) { 4209 case SCTP_IERROR_AUTH_BAD_HMAC: 4210 /* Generate the ERROR chunk and discard the rest 4211 * of the packet 4212 */ 4213 err_chunk = sctp_make_op_error(asoc, chunk, 4214 SCTP_ERROR_UNSUP_HMAC, 4215 &auth_hdr->hmac_id, 4216 sizeof(__u16), 0); 4217 if (err_chunk) { 4218 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4219 SCTP_CHUNK(err_chunk)); 4220 } 4221 /* Fall Through */ 4222 case SCTP_IERROR_AUTH_BAD_KEYID: 4223 case SCTP_IERROR_BAD_SIG: 4224 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4225 4226 case SCTP_IERROR_PROTO_VIOLATION: 4227 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4228 commands); 4229 4230 case SCTP_IERROR_NOMEM: 4231 return SCTP_DISPOSITION_NOMEM; 4232 4233 default: /* Prevent gcc warnings */ 4234 break; 4235 } 4236 4237 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4238 struct sctp_ulpevent *ev; 4239 4240 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4241 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4242 4243 if (!ev) 4244 return -ENOMEM; 4245 4246 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4247 SCTP_ULPEVENT(ev)); 4248 } 4249 4250 return SCTP_DISPOSITION_CONSUME; 4251 } 4252 4253 /* 4254 * Process an unknown chunk. 4255 * 4256 * Section: 3.2. Also, 2.1 in the implementor's guide. 4257 * 4258 * Chunk Types are encoded such that the highest-order two bits specify 4259 * the action that must be taken if the processing endpoint does not 4260 * recognize the Chunk Type. 4261 * 4262 * 00 - Stop processing this SCTP packet and discard it, do not process 4263 * any further chunks within it. 4264 * 4265 * 01 - Stop processing this SCTP packet and discard it, do not process 4266 * any further chunks within it, and report the unrecognized 4267 * chunk in an 'Unrecognized Chunk Type'. 4268 * 4269 * 10 - Skip this chunk and continue processing. 4270 * 4271 * 11 - Skip this chunk and continue processing, but report in an ERROR 4272 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4273 * 4274 * The return value is the disposition of the chunk. 4275 */ 4276 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4277 const struct sctp_endpoint *ep, 4278 const struct sctp_association *asoc, 4279 const union sctp_subtype type, 4280 void *arg, 4281 struct sctp_cmd_seq *commands) 4282 { 4283 struct sctp_chunk *unk_chunk = arg; 4284 struct sctp_chunk *err_chunk; 4285 struct sctp_chunkhdr *hdr; 4286 4287 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4288 4289 if (!sctp_vtag_verify(unk_chunk, asoc)) 4290 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4291 4292 /* Make sure that the chunk has a valid length. 4293 * Since we don't know the chunk type, we use a general 4294 * chunkhdr structure to make a comparison. 4295 */ 4296 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4297 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4298 commands); 4299 4300 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4301 case SCTP_CID_ACTION_DISCARD: 4302 /* Discard the packet. */ 4303 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4304 case SCTP_CID_ACTION_DISCARD_ERR: 4305 /* Generate an ERROR chunk as response. */ 4306 hdr = unk_chunk->chunk_hdr; 4307 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4308 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4309 SCTP_PAD4(ntohs(hdr->length)), 4310 0); 4311 if (err_chunk) { 4312 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4313 SCTP_CHUNK(err_chunk)); 4314 } 4315 4316 /* Discard the packet. */ 4317 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4318 return SCTP_DISPOSITION_CONSUME; 4319 case SCTP_CID_ACTION_SKIP: 4320 /* Skip the chunk. */ 4321 return SCTP_DISPOSITION_DISCARD; 4322 case SCTP_CID_ACTION_SKIP_ERR: 4323 /* Generate an ERROR chunk as response. */ 4324 hdr = unk_chunk->chunk_hdr; 4325 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4326 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4327 SCTP_PAD4(ntohs(hdr->length)), 4328 0); 4329 if (err_chunk) { 4330 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4331 SCTP_CHUNK(err_chunk)); 4332 } 4333 /* Skip the chunk. */ 4334 return SCTP_DISPOSITION_CONSUME; 4335 default: 4336 break; 4337 } 4338 4339 return SCTP_DISPOSITION_DISCARD; 4340 } 4341 4342 /* 4343 * Discard the chunk. 4344 * 4345 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4346 * [Too numerous to mention...] 4347 * Verification Tag: No verification needed. 4348 * Inputs 4349 * (endpoint, asoc, chunk) 4350 * 4351 * Outputs 4352 * (asoc, reply_msg, msg_up, timers, counters) 4353 * 4354 * The return value is the disposition of the chunk. 4355 */ 4356 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4357 const struct sctp_endpoint *ep, 4358 const struct sctp_association *asoc, 4359 const union sctp_subtype type, 4360 void *arg, 4361 struct sctp_cmd_seq *commands) 4362 { 4363 struct sctp_chunk *chunk = arg; 4364 4365 /* Make sure that the chunk has a valid length. 4366 * Since we don't know the chunk type, we use a general 4367 * chunkhdr structure to make a comparison. 4368 */ 4369 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4370 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4371 commands); 4372 4373 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4374 4375 return SCTP_DISPOSITION_DISCARD; 4376 } 4377 4378 /* 4379 * Discard the whole packet. 4380 * 4381 * Section: 8.4 2) 4382 * 4383 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4384 * silently discard the OOTB packet and take no further action. 4385 * 4386 * Verification Tag: No verification necessary 4387 * 4388 * Inputs 4389 * (endpoint, asoc, chunk) 4390 * 4391 * Outputs 4392 * (asoc, reply_msg, msg_up, timers, counters) 4393 * 4394 * The return value is the disposition of the chunk. 4395 */ 4396 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4397 const struct sctp_endpoint *ep, 4398 const struct sctp_association *asoc, 4399 const union sctp_subtype type, 4400 void *arg, struct sctp_cmd_seq *commands) 4401 { 4402 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4403 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4404 4405 return SCTP_DISPOSITION_CONSUME; 4406 } 4407 4408 4409 /* 4410 * The other end is violating protocol. 4411 * 4412 * Section: Not specified 4413 * Verification Tag: Not specified 4414 * Inputs 4415 * (endpoint, asoc, chunk) 4416 * 4417 * Outputs 4418 * (asoc, reply_msg, msg_up, timers, counters) 4419 * 4420 * We simply tag the chunk as a violation. The state machine will log 4421 * the violation and continue. 4422 */ 4423 enum sctp_disposition sctp_sf_violation(struct net *net, 4424 const struct sctp_endpoint *ep, 4425 const struct sctp_association *asoc, 4426 const union sctp_subtype type, 4427 void *arg, 4428 struct sctp_cmd_seq *commands) 4429 { 4430 struct sctp_chunk *chunk = arg; 4431 4432 /* Make sure that the chunk has a valid length. */ 4433 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4434 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4435 commands); 4436 4437 return SCTP_DISPOSITION_VIOLATION; 4438 } 4439 4440 /* 4441 * Common function to handle a protocol violation. 4442 */ 4443 static enum sctp_disposition sctp_sf_abort_violation( 4444 struct net *net, 4445 const struct sctp_endpoint *ep, 4446 const struct sctp_association *asoc, 4447 void *arg, 4448 struct sctp_cmd_seq *commands, 4449 const __u8 *payload, 4450 const size_t paylen) 4451 { 4452 struct sctp_packet *packet = NULL; 4453 struct sctp_chunk *chunk = arg; 4454 struct sctp_chunk *abort = NULL; 4455 4456 /* SCTP-AUTH, Section 6.3: 4457 * It should be noted that if the receiver wants to tear 4458 * down an association in an authenticated way only, the 4459 * handling of malformed packets should not result in 4460 * tearing down the association. 4461 * 4462 * This means that if we only want to abort associations 4463 * in an authenticated way (i.e AUTH+ABORT), then we 4464 * can't destroy this association just because the packet 4465 * was malformed. 4466 */ 4467 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4468 goto discard; 4469 4470 /* Make the abort chunk. */ 4471 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4472 if (!abort) 4473 goto nomem; 4474 4475 if (asoc) { 4476 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4477 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4478 !asoc->peer.i.init_tag) { 4479 struct sctp_initack_chunk *initack; 4480 4481 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4482 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4483 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4484 else { 4485 unsigned int inittag; 4486 4487 inittag = ntohl(initack->init_hdr.init_tag); 4488 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4489 SCTP_U32(inittag)); 4490 } 4491 } 4492 4493 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4494 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4495 4496 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4497 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4498 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4499 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4500 SCTP_ERROR(ECONNREFUSED)); 4501 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4502 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4503 } else { 4504 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4505 SCTP_ERROR(ECONNABORTED)); 4506 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4507 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4508 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4509 } 4510 } else { 4511 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4512 4513 if (!packet) 4514 goto nomem_pkt; 4515 4516 if (sctp_test_T_bit(abort)) 4517 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4518 4519 abort->skb->sk = ep->base.sk; 4520 4521 sctp_packet_append_chunk(packet, abort); 4522 4523 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4524 SCTP_PACKET(packet)); 4525 4526 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4527 } 4528 4529 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4530 4531 discard: 4532 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4533 return SCTP_DISPOSITION_ABORT; 4534 4535 nomem_pkt: 4536 sctp_chunk_free(abort); 4537 nomem: 4538 return SCTP_DISPOSITION_NOMEM; 4539 } 4540 4541 /* 4542 * Handle a protocol violation when the chunk length is invalid. 4543 * "Invalid" length is identified as smaller than the minimal length a 4544 * given chunk can be. For example, a SACK chunk has invalid length 4545 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4546 * 4547 * We inform the other end by sending an ABORT with a Protocol Violation 4548 * error code. 4549 * 4550 * Section: Not specified 4551 * Verification Tag: Nothing to do 4552 * Inputs 4553 * (endpoint, asoc, chunk) 4554 * 4555 * Outputs 4556 * (reply_msg, msg_up, counters) 4557 * 4558 * Generate an ABORT chunk and terminate the association. 4559 */ 4560 static enum sctp_disposition sctp_sf_violation_chunklen( 4561 struct net *net, 4562 const struct sctp_endpoint *ep, 4563 const struct sctp_association *asoc, 4564 const union sctp_subtype type, 4565 void *arg, 4566 struct sctp_cmd_seq *commands) 4567 { 4568 static const char err_str[] = "The following chunk had invalid length:"; 4569 4570 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4571 sizeof(err_str)); 4572 } 4573 4574 /* 4575 * Handle a protocol violation when the parameter length is invalid. 4576 * If the length is smaller than the minimum length of a given parameter, 4577 * or accumulated length in multi parameters exceeds the end of the chunk, 4578 * the length is considered as invalid. 4579 */ 4580 static enum sctp_disposition sctp_sf_violation_paramlen( 4581 struct net *net, 4582 const struct sctp_endpoint *ep, 4583 const struct sctp_association *asoc, 4584 const union sctp_subtype type, 4585 void *arg, void *ext, 4586 struct sctp_cmd_seq *commands) 4587 { 4588 struct sctp_paramhdr *param = ext; 4589 struct sctp_chunk *abort = NULL; 4590 struct sctp_chunk *chunk = arg; 4591 4592 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4593 goto discard; 4594 4595 /* Make the abort chunk. */ 4596 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4597 if (!abort) 4598 goto nomem; 4599 4600 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4601 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4602 4603 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4604 SCTP_ERROR(ECONNABORTED)); 4605 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4606 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4607 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4608 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4609 4610 discard: 4611 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4612 return SCTP_DISPOSITION_ABORT; 4613 nomem: 4614 return SCTP_DISPOSITION_NOMEM; 4615 } 4616 4617 /* Handle a protocol violation when the peer trying to advance the 4618 * cumulative tsn ack to a point beyond the max tsn currently sent. 4619 * 4620 * We inform the other end by sending an ABORT with a Protocol Violation 4621 * error code. 4622 */ 4623 static enum sctp_disposition sctp_sf_violation_ctsn( 4624 struct net *net, 4625 const struct sctp_endpoint *ep, 4626 const struct sctp_association *asoc, 4627 const union sctp_subtype type, 4628 void *arg, 4629 struct sctp_cmd_seq *commands) 4630 { 4631 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4632 4633 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4634 sizeof(err_str)); 4635 } 4636 4637 /* Handle protocol violation of an invalid chunk bundling. For example, 4638 * when we have an association and we receive bundled INIT-ACK, or 4639 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4640 * statement from the specs. Additionally, there might be an attacker 4641 * on the path and we may not want to continue this communication. 4642 */ 4643 static enum sctp_disposition sctp_sf_violation_chunk( 4644 struct net *net, 4645 const struct sctp_endpoint *ep, 4646 const struct sctp_association *asoc, 4647 const union sctp_subtype type, 4648 void *arg, 4649 struct sctp_cmd_seq *commands) 4650 { 4651 static const char err_str[] = "The following chunk violates protocol:"; 4652 4653 if (!asoc) 4654 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4655 4656 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4657 sizeof(err_str)); 4658 } 4659 /*************************************************************************** 4660 * These are the state functions for handling primitive (Section 10) events. 4661 ***************************************************************************/ 4662 /* 4663 * sctp_sf_do_prm_asoc 4664 * 4665 * Section: 10.1 ULP-to-SCTP 4666 * B) Associate 4667 * 4668 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4669 * outbound stream count) 4670 * -> association id [,destination transport addr list] [,outbound stream 4671 * count] 4672 * 4673 * This primitive allows the upper layer to initiate an association to a 4674 * specific peer endpoint. 4675 * 4676 * The peer endpoint shall be specified by one of the transport addresses 4677 * which defines the endpoint (see Section 1.4). If the local SCTP 4678 * instance has not been initialized, the ASSOCIATE is considered an 4679 * error. 4680 * [This is not relevant for the kernel implementation since we do all 4681 * initialization at boot time. It we hadn't initialized we wouldn't 4682 * get anywhere near this code.] 4683 * 4684 * An association id, which is a local handle to the SCTP association, 4685 * will be returned on successful establishment of the association. If 4686 * SCTP is not able to open an SCTP association with the peer endpoint, 4687 * an error is returned. 4688 * [In the kernel implementation, the struct sctp_association needs to 4689 * be created BEFORE causing this primitive to run.] 4690 * 4691 * Other association parameters may be returned, including the 4692 * complete destination transport addresses of the peer as well as the 4693 * outbound stream count of the local endpoint. One of the transport 4694 * address from the returned destination addresses will be selected by 4695 * the local endpoint as default primary path for sending SCTP packets 4696 * to this peer. The returned "destination transport addr list" can 4697 * be used by the ULP to change the default primary path or to force 4698 * sending a packet to a specific transport address. [All of this 4699 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4700 * function.] 4701 * 4702 * Mandatory attributes: 4703 * 4704 * o local SCTP instance name - obtained from the INITIALIZE operation. 4705 * [This is the argument asoc.] 4706 * o destination transport addr - specified as one of the transport 4707 * addresses of the peer endpoint with which the association is to be 4708 * established. 4709 * [This is asoc->peer.active_path.] 4710 * o outbound stream count - the number of outbound streams the ULP 4711 * would like to open towards this peer endpoint. 4712 * [BUG: This is not currently implemented.] 4713 * Optional attributes: 4714 * 4715 * None. 4716 * 4717 * The return value is a disposition. 4718 */ 4719 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4720 const struct sctp_endpoint *ep, 4721 const struct sctp_association *asoc, 4722 const union sctp_subtype type, 4723 void *arg, 4724 struct sctp_cmd_seq *commands) 4725 { 4726 struct sctp_association *my_asoc; 4727 struct sctp_chunk *repl; 4728 4729 /* The comment below says that we enter COOKIE-WAIT AFTER 4730 * sending the INIT, but that doesn't actually work in our 4731 * implementation... 4732 */ 4733 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4734 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4735 4736 /* RFC 2960 5.1 Normal Establishment of an Association 4737 * 4738 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4739 * must provide its Verification Tag (Tag_A) in the Initiate 4740 * Tag field. Tag_A SHOULD be a random number in the range of 4741 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4742 */ 4743 4744 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4745 if (!repl) 4746 goto nomem; 4747 4748 /* Choose transport for INIT. */ 4749 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4750 SCTP_CHUNK(repl)); 4751 4752 /* Cast away the const modifier, as we want to just 4753 * rerun it through as a sideffect. 4754 */ 4755 my_asoc = (struct sctp_association *)asoc; 4756 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4757 4758 /* After sending the INIT, "A" starts the T1-init timer and 4759 * enters the COOKIE-WAIT state. 4760 */ 4761 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4762 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4763 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4764 return SCTP_DISPOSITION_CONSUME; 4765 4766 nomem: 4767 return SCTP_DISPOSITION_NOMEM; 4768 } 4769 4770 /* 4771 * Process the SEND primitive. 4772 * 4773 * Section: 10.1 ULP-to-SCTP 4774 * E) Send 4775 * 4776 * Format: SEND(association id, buffer address, byte count [,context] 4777 * [,stream id] [,life time] [,destination transport address] 4778 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4779 * -> result 4780 * 4781 * This is the main method to send user data via SCTP. 4782 * 4783 * Mandatory attributes: 4784 * 4785 * o association id - local handle to the SCTP association 4786 * 4787 * o buffer address - the location where the user message to be 4788 * transmitted is stored; 4789 * 4790 * o byte count - The size of the user data in number of bytes; 4791 * 4792 * Optional attributes: 4793 * 4794 * o context - an optional 32 bit integer that will be carried in the 4795 * sending failure notification to the ULP if the transportation of 4796 * this User Message fails. 4797 * 4798 * o stream id - to indicate which stream to send the data on. If not 4799 * specified, stream 0 will be used. 4800 * 4801 * o life time - specifies the life time of the user data. The user data 4802 * will not be sent by SCTP after the life time expires. This 4803 * parameter can be used to avoid efforts to transmit stale 4804 * user messages. SCTP notifies the ULP if the data cannot be 4805 * initiated to transport (i.e. sent to the destination via SCTP's 4806 * send primitive) within the life time variable. However, the 4807 * user data will be transmitted if SCTP has attempted to transmit a 4808 * chunk before the life time expired. 4809 * 4810 * o destination transport address - specified as one of the destination 4811 * transport addresses of the peer endpoint to which this packet 4812 * should be sent. Whenever possible, SCTP should use this destination 4813 * transport address for sending the packets, instead of the current 4814 * primary path. 4815 * 4816 * o unorder flag - this flag, if present, indicates that the user 4817 * would like the data delivered in an unordered fashion to the peer 4818 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4819 * message). 4820 * 4821 * o no-bundle flag - instructs SCTP not to bundle this user data with 4822 * other outbound DATA chunks. SCTP MAY still bundle even when 4823 * this flag is present, when faced with network congestion. 4824 * 4825 * o payload protocol-id - A 32 bit unsigned integer that is to be 4826 * passed to the peer indicating the type of payload protocol data 4827 * being transmitted. This value is passed as opaque data by SCTP. 4828 * 4829 * The return value is the disposition. 4830 */ 4831 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 4832 const struct sctp_endpoint *ep, 4833 const struct sctp_association *asoc, 4834 const union sctp_subtype type, 4835 void *arg, 4836 struct sctp_cmd_seq *commands) 4837 { 4838 struct sctp_datamsg *msg = arg; 4839 4840 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4841 return SCTP_DISPOSITION_CONSUME; 4842 } 4843 4844 /* 4845 * Process the SHUTDOWN primitive. 4846 * 4847 * Section: 10.1: 4848 * C) Shutdown 4849 * 4850 * Format: SHUTDOWN(association id) 4851 * -> result 4852 * 4853 * Gracefully closes an association. Any locally queued user data 4854 * will be delivered to the peer. The association will be terminated only 4855 * after the peer acknowledges all the SCTP packets sent. A success code 4856 * will be returned on successful termination of the association. If 4857 * attempting to terminate the association results in a failure, an error 4858 * code shall be returned. 4859 * 4860 * Mandatory attributes: 4861 * 4862 * o association id - local handle to the SCTP association 4863 * 4864 * Optional attributes: 4865 * 4866 * None. 4867 * 4868 * The return value is the disposition. 4869 */ 4870 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 4871 struct net *net, 4872 const struct sctp_endpoint *ep, 4873 const struct sctp_association *asoc, 4874 const union sctp_subtype type, 4875 void *arg, 4876 struct sctp_cmd_seq *commands) 4877 { 4878 enum sctp_disposition disposition; 4879 4880 /* From 9.2 Shutdown of an Association 4881 * Upon receipt of the SHUTDOWN primitive from its upper 4882 * layer, the endpoint enters SHUTDOWN-PENDING state and 4883 * remains there until all outstanding data has been 4884 * acknowledged by its peer. The endpoint accepts no new data 4885 * from its upper layer, but retransmits data to the far end 4886 * if necessary to fill gaps. 4887 */ 4888 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4889 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4890 4891 disposition = SCTP_DISPOSITION_CONSUME; 4892 if (sctp_outq_is_empty(&asoc->outqueue)) { 4893 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4894 arg, commands); 4895 } 4896 4897 return disposition; 4898 } 4899 4900 /* 4901 * Process the ABORT primitive. 4902 * 4903 * Section: 10.1: 4904 * C) Abort 4905 * 4906 * Format: Abort(association id [, cause code]) 4907 * -> result 4908 * 4909 * Ungracefully closes an association. Any locally queued user data 4910 * will be discarded and an ABORT chunk is sent to the peer. A success code 4911 * will be returned on successful abortion of the association. If 4912 * attempting to abort the association results in a failure, an error 4913 * code shall be returned. 4914 * 4915 * Mandatory attributes: 4916 * 4917 * o association id - local handle to the SCTP association 4918 * 4919 * Optional attributes: 4920 * 4921 * o cause code - reason of the abort to be passed to the peer 4922 * 4923 * None. 4924 * 4925 * The return value is the disposition. 4926 */ 4927 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 4928 struct net *net, 4929 const struct sctp_endpoint *ep, 4930 const struct sctp_association *asoc, 4931 const union sctp_subtype type, 4932 void *arg, 4933 struct sctp_cmd_seq *commands) 4934 { 4935 /* From 9.1 Abort of an Association 4936 * Upon receipt of the ABORT primitive from its upper 4937 * layer, the endpoint enters CLOSED state and 4938 * discard all outstanding data has been 4939 * acknowledged by its peer. The endpoint accepts no new data 4940 * from its upper layer, but retransmits data to the far end 4941 * if necessary to fill gaps. 4942 */ 4943 struct sctp_chunk *abort = arg; 4944 4945 if (abort) 4946 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4947 4948 /* Even if we can't send the ABORT due to low memory delete the 4949 * TCB. This is a departure from our typical NOMEM handling. 4950 */ 4951 4952 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4953 SCTP_ERROR(ECONNABORTED)); 4954 /* Delete the established association. */ 4955 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4956 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4957 4958 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4959 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4960 4961 return SCTP_DISPOSITION_ABORT; 4962 } 4963 4964 /* We tried an illegal operation on an association which is closed. */ 4965 enum sctp_disposition sctp_sf_error_closed(struct net *net, 4966 const struct sctp_endpoint *ep, 4967 const struct sctp_association *asoc, 4968 const union sctp_subtype type, 4969 void *arg, 4970 struct sctp_cmd_seq *commands) 4971 { 4972 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4973 return SCTP_DISPOSITION_CONSUME; 4974 } 4975 4976 /* We tried an illegal operation on an association which is shutting 4977 * down. 4978 */ 4979 enum sctp_disposition sctp_sf_error_shutdown( 4980 struct net *net, 4981 const struct sctp_endpoint *ep, 4982 const struct sctp_association *asoc, 4983 const union sctp_subtype type, 4984 void *arg, 4985 struct sctp_cmd_seq *commands) 4986 { 4987 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4988 SCTP_ERROR(-ESHUTDOWN)); 4989 return SCTP_DISPOSITION_CONSUME; 4990 } 4991 4992 /* 4993 * sctp_cookie_wait_prm_shutdown 4994 * 4995 * Section: 4 Note: 2 4996 * Verification Tag: 4997 * Inputs 4998 * (endpoint, asoc) 4999 * 5000 * The RFC does not explicitly address this issue, but is the route through the 5001 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5002 * 5003 * Outputs 5004 * (timers) 5005 */ 5006 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5007 struct net *net, 5008 const struct sctp_endpoint *ep, 5009 const struct sctp_association *asoc, 5010 const union sctp_subtype type, 5011 void *arg, 5012 struct sctp_cmd_seq *commands) 5013 { 5014 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5015 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5016 5017 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5018 SCTP_STATE(SCTP_STATE_CLOSED)); 5019 5020 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5021 5022 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5023 5024 return SCTP_DISPOSITION_DELETE_TCB; 5025 } 5026 5027 /* 5028 * sctp_cookie_echoed_prm_shutdown 5029 * 5030 * Section: 4 Note: 2 5031 * Verification Tag: 5032 * Inputs 5033 * (endpoint, asoc) 5034 * 5035 * The RFC does not explcitly address this issue, but is the route through the 5036 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5037 * 5038 * Outputs 5039 * (timers) 5040 */ 5041 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5042 struct net *net, 5043 const struct sctp_endpoint *ep, 5044 const struct sctp_association *asoc, 5045 const union sctp_subtype type, 5046 void *arg, 5047 struct sctp_cmd_seq *commands) 5048 { 5049 /* There is a single T1 timer, so we should be able to use 5050 * common function with the COOKIE-WAIT state. 5051 */ 5052 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5053 } 5054 5055 /* 5056 * sctp_sf_cookie_wait_prm_abort 5057 * 5058 * Section: 4 Note: 2 5059 * Verification Tag: 5060 * Inputs 5061 * (endpoint, asoc) 5062 * 5063 * The RFC does not explicitly address this issue, but is the route through the 5064 * state table when someone issues an abort while in COOKIE_WAIT state. 5065 * 5066 * Outputs 5067 * (timers) 5068 */ 5069 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5070 struct net *net, 5071 const struct sctp_endpoint *ep, 5072 const struct sctp_association *asoc, 5073 const union sctp_subtype type, 5074 void *arg, 5075 struct sctp_cmd_seq *commands) 5076 { 5077 struct sctp_chunk *abort = arg; 5078 5079 /* Stop T1-init timer */ 5080 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5081 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5082 5083 if (abort) 5084 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5085 5086 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5087 SCTP_STATE(SCTP_STATE_CLOSED)); 5088 5089 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5090 5091 /* Even if we can't send the ABORT due to low memory delete the 5092 * TCB. This is a departure from our typical NOMEM handling. 5093 */ 5094 5095 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5096 SCTP_ERROR(ECONNREFUSED)); 5097 /* Delete the established association. */ 5098 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5099 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5100 5101 return SCTP_DISPOSITION_ABORT; 5102 } 5103 5104 /* 5105 * sctp_sf_cookie_echoed_prm_abort 5106 * 5107 * Section: 4 Note: 3 5108 * Verification Tag: 5109 * Inputs 5110 * (endpoint, asoc) 5111 * 5112 * The RFC does not explcitly address this issue, but is the route through the 5113 * state table when someone issues an abort while in COOKIE_ECHOED state. 5114 * 5115 * Outputs 5116 * (timers) 5117 */ 5118 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5119 struct net *net, 5120 const struct sctp_endpoint *ep, 5121 const struct sctp_association *asoc, 5122 const union sctp_subtype type, 5123 void *arg, 5124 struct sctp_cmd_seq *commands) 5125 { 5126 /* There is a single T1 timer, so we should be able to use 5127 * common function with the COOKIE-WAIT state. 5128 */ 5129 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5130 } 5131 5132 /* 5133 * sctp_sf_shutdown_pending_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-PENDING state. 5140 * 5141 * Outputs 5142 * (timers) 5143 */ 5144 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5145 struct net *net, 5146 const struct sctp_endpoint *ep, 5147 const struct sctp_association *asoc, 5148 const union sctp_subtype type, 5149 void *arg, 5150 struct sctp_cmd_seq *commands) 5151 { 5152 /* Stop the T5-shutdown guard timer. */ 5153 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5154 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5155 5156 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5157 } 5158 5159 /* 5160 * sctp_sf_shutdown_sent_prm_abort 5161 * 5162 * Inputs 5163 * (endpoint, asoc) 5164 * 5165 * The RFC does not explicitly address this issue, but is the route through the 5166 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5167 * 5168 * Outputs 5169 * (timers) 5170 */ 5171 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5172 struct net *net, 5173 const struct sctp_endpoint *ep, 5174 const struct sctp_association *asoc, 5175 const union sctp_subtype type, 5176 void *arg, 5177 struct sctp_cmd_seq *commands) 5178 { 5179 /* Stop the T2-shutdown timer. */ 5180 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5181 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5182 5183 /* Stop the T5-shutdown guard timer. */ 5184 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5185 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5186 5187 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5188 } 5189 5190 /* 5191 * sctp_sf_cookie_echoed_prm_abort 5192 * 5193 * Inputs 5194 * (endpoint, asoc) 5195 * 5196 * The RFC does not explcitly address this issue, but is the route through the 5197 * state table when someone issues an abort while in COOKIE_ECHOED state. 5198 * 5199 * Outputs 5200 * (timers) 5201 */ 5202 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5203 struct net *net, 5204 const struct sctp_endpoint *ep, 5205 const struct sctp_association *asoc, 5206 const union sctp_subtype type, 5207 void *arg, 5208 struct sctp_cmd_seq *commands) 5209 { 5210 /* The same T2 timer, so we should be able to use 5211 * common function with the SHUTDOWN-SENT state. 5212 */ 5213 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5214 } 5215 5216 /* 5217 * Process the REQUESTHEARTBEAT primitive 5218 * 5219 * 10.1 ULP-to-SCTP 5220 * J) Request Heartbeat 5221 * 5222 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5223 * 5224 * -> result 5225 * 5226 * Instructs the local endpoint to perform a HeartBeat on the specified 5227 * destination transport address of the given association. The returned 5228 * result should indicate whether the transmission of the HEARTBEAT 5229 * chunk to the destination address is successful. 5230 * 5231 * Mandatory attributes: 5232 * 5233 * o association id - local handle to the SCTP association 5234 * 5235 * o destination transport address - the transport address of the 5236 * association on which a heartbeat should be issued. 5237 */ 5238 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5239 struct net *net, 5240 const struct sctp_endpoint *ep, 5241 const struct sctp_association *asoc, 5242 const union sctp_subtype type, 5243 void *arg, 5244 struct sctp_cmd_seq *commands) 5245 { 5246 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5247 (struct sctp_transport *)arg, commands)) 5248 return SCTP_DISPOSITION_NOMEM; 5249 5250 /* 5251 * RFC 2960 (bis), section 8.3 5252 * 5253 * D) Request an on-demand HEARTBEAT on a specific destination 5254 * transport address of a given association. 5255 * 5256 * The endpoint should increment the respective error counter of 5257 * the destination transport address each time a HEARTBEAT is sent 5258 * to that address and not acknowledged within one RTO. 5259 * 5260 */ 5261 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5262 SCTP_TRANSPORT(arg)); 5263 return SCTP_DISPOSITION_CONSUME; 5264 } 5265 5266 /* 5267 * ADDIP Section 4.1 ASCONF Chunk Procedures 5268 * When an endpoint has an ASCONF signaled change to be sent to the 5269 * remote endpoint it should do A1 to A9 5270 */ 5271 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5272 const struct sctp_endpoint *ep, 5273 const struct sctp_association *asoc, 5274 const union sctp_subtype type, 5275 void *arg, 5276 struct sctp_cmd_seq *commands) 5277 { 5278 struct sctp_chunk *chunk = arg; 5279 5280 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5281 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5282 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5283 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5284 return SCTP_DISPOSITION_CONSUME; 5285 } 5286 5287 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5288 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5289 const struct sctp_endpoint *ep, 5290 const struct sctp_association *asoc, 5291 const union sctp_subtype type, 5292 void *arg, 5293 struct sctp_cmd_seq *commands) 5294 { 5295 struct sctp_chunk *chunk = arg; 5296 5297 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5298 return SCTP_DISPOSITION_CONSUME; 5299 } 5300 5301 /* 5302 * Ignore the primitive event 5303 * 5304 * The return value is the disposition of the primitive. 5305 */ 5306 enum sctp_disposition sctp_sf_ignore_primitive( 5307 struct net *net, 5308 const struct sctp_endpoint *ep, 5309 const struct sctp_association *asoc, 5310 const union sctp_subtype type, 5311 void *arg, 5312 struct sctp_cmd_seq *commands) 5313 { 5314 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5315 type.primitive); 5316 5317 return SCTP_DISPOSITION_DISCARD; 5318 } 5319 5320 /*************************************************************************** 5321 * These are the state functions for the OTHER events. 5322 ***************************************************************************/ 5323 5324 /* 5325 * When the SCTP stack has no more user data to send or retransmit, this 5326 * notification is given to the user. Also, at the time when a user app 5327 * subscribes to this event, if there is no data to be sent or 5328 * retransmit, the stack will immediately send up this notification. 5329 */ 5330 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5331 struct net *net, 5332 const struct sctp_endpoint *ep, 5333 const struct sctp_association *asoc, 5334 const union sctp_subtype type, 5335 void *arg, 5336 struct sctp_cmd_seq *commands) 5337 { 5338 struct sctp_ulpevent *event; 5339 5340 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5341 if (!event) 5342 return SCTP_DISPOSITION_NOMEM; 5343 5344 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5345 5346 return SCTP_DISPOSITION_CONSUME; 5347 } 5348 5349 /* 5350 * Start the shutdown negotiation. 5351 * 5352 * From Section 9.2: 5353 * Once all its outstanding data has been acknowledged, the endpoint 5354 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5355 * TSN Ack field the last sequential TSN it has received from the peer. 5356 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5357 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5358 * with the updated last sequential TSN received from its peer. 5359 * 5360 * The return value is the disposition. 5361 */ 5362 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5363 struct net *net, 5364 const struct sctp_endpoint *ep, 5365 const struct sctp_association *asoc, 5366 const union sctp_subtype type, 5367 void *arg, 5368 struct sctp_cmd_seq *commands) 5369 { 5370 struct sctp_chunk *reply; 5371 5372 /* Once all its outstanding data has been acknowledged, the 5373 * endpoint shall send a SHUTDOWN chunk to its peer including 5374 * in the Cumulative TSN Ack field the last sequential TSN it 5375 * has received from the peer. 5376 */ 5377 reply = sctp_make_shutdown(asoc, NULL); 5378 if (!reply) 5379 goto nomem; 5380 5381 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5382 * T2-shutdown timer. 5383 */ 5384 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5385 5386 /* It shall then start the T2-shutdown timer */ 5387 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5388 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5389 5390 /* RFC 4960 Section 9.2 5391 * The sender of the SHUTDOWN MAY also start an overall guard timer 5392 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5393 */ 5394 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5395 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5396 5397 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5398 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5399 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5400 5401 /* and enter the SHUTDOWN-SENT state. */ 5402 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5403 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5404 5405 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5406 * 5407 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5408 * or SHUTDOWN-ACK. 5409 */ 5410 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5411 5412 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5413 5414 return SCTP_DISPOSITION_CONSUME; 5415 5416 nomem: 5417 return SCTP_DISPOSITION_NOMEM; 5418 } 5419 5420 /* 5421 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5422 * 5423 * From Section 9.2: 5424 * 5425 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5426 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5427 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5428 * endpoint must re-send the SHUTDOWN ACK. 5429 * 5430 * The return value is the disposition. 5431 */ 5432 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5433 struct net *net, 5434 const struct sctp_endpoint *ep, 5435 const struct sctp_association *asoc, 5436 const union sctp_subtype type, 5437 void *arg, 5438 struct sctp_cmd_seq *commands) 5439 { 5440 struct sctp_chunk *chunk = arg; 5441 struct sctp_chunk *reply; 5442 5443 /* There are 2 ways of getting here: 5444 * 1) called in response to a SHUTDOWN chunk 5445 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5446 * 5447 * For the case (2), the arg parameter is set to NULL. We need 5448 * to check that we have a chunk before accessing it's fields. 5449 */ 5450 if (chunk) { 5451 if (!sctp_vtag_verify(chunk, asoc)) 5452 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5453 commands); 5454 5455 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5456 if (!sctp_chunk_length_valid( 5457 chunk, sizeof(struct sctp_shutdown_chunk))) 5458 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5459 arg, commands); 5460 } 5461 5462 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5463 * shall send a SHUTDOWN ACK ... 5464 */ 5465 reply = sctp_make_shutdown_ack(asoc, chunk); 5466 if (!reply) 5467 goto nomem; 5468 5469 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5470 * the T2-shutdown timer. 5471 */ 5472 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5473 5474 /* and start/restart a T2-shutdown timer of its own, */ 5475 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5476 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5477 5478 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5479 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5480 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5481 5482 /* Enter the SHUTDOWN-ACK-SENT state. */ 5483 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5484 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5485 5486 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5487 * 5488 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5489 * or SHUTDOWN-ACK. 5490 */ 5491 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5492 5493 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5494 5495 return SCTP_DISPOSITION_CONSUME; 5496 5497 nomem: 5498 return SCTP_DISPOSITION_NOMEM; 5499 } 5500 5501 /* 5502 * Ignore the event defined as other 5503 * 5504 * The return value is the disposition of the event. 5505 */ 5506 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5507 const struct sctp_endpoint *ep, 5508 const struct sctp_association *asoc, 5509 const union sctp_subtype type, 5510 void *arg, 5511 struct sctp_cmd_seq *commands) 5512 { 5513 pr_debug("%s: the event other type:%d is ignored\n", 5514 __func__, type.other); 5515 5516 return SCTP_DISPOSITION_DISCARD; 5517 } 5518 5519 /************************************************************ 5520 * These are the state functions for handling timeout events. 5521 ************************************************************/ 5522 5523 /* 5524 * RTX Timeout 5525 * 5526 * Section: 6.3.3 Handle T3-rtx Expiration 5527 * 5528 * Whenever the retransmission timer T3-rtx expires for a destination 5529 * address, do the following: 5530 * [See below] 5531 * 5532 * The return value is the disposition of the chunk. 5533 */ 5534 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5535 const struct sctp_endpoint *ep, 5536 const struct sctp_association *asoc, 5537 const union sctp_subtype type, 5538 void *arg, 5539 struct sctp_cmd_seq *commands) 5540 { 5541 struct sctp_transport *transport = arg; 5542 5543 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5544 5545 if (asoc->overall_error_count >= asoc->max_retrans) { 5546 if (asoc->peer.zero_window_announced && 5547 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5548 /* 5549 * We are here likely because the receiver had its rwnd 5550 * closed for a while and we have not been able to 5551 * transmit the locally queued data within the maximum 5552 * retransmission attempts limit. Start the T5 5553 * shutdown guard timer to give the receiver one last 5554 * chance and some additional time to recover before 5555 * aborting. 5556 */ 5557 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5558 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5559 } else { 5560 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5561 SCTP_ERROR(ETIMEDOUT)); 5562 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5563 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5564 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5565 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5566 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5567 return SCTP_DISPOSITION_DELETE_TCB; 5568 } 5569 } 5570 5571 /* E1) For the destination address for which the timer 5572 * expires, adjust its ssthresh with rules defined in Section 5573 * 7.2.3 and set the cwnd <- MTU. 5574 */ 5575 5576 /* E2) For the destination address for which the timer 5577 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5578 * maximum value discussed in rule C7 above (RTO.max) may be 5579 * used to provide an upper bound to this doubling operation. 5580 */ 5581 5582 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5583 * outstanding DATA chunks for the address for which the 5584 * T3-rtx has expired will fit into a single packet, subject 5585 * to the MTU constraint for the path corresponding to the 5586 * destination transport address to which the retransmission 5587 * is being sent (this may be different from the address for 5588 * which the timer expires [see Section 6.4]). Call this 5589 * value K. Bundle and retransmit those K DATA chunks in a 5590 * single packet to the destination endpoint. 5591 * 5592 * Note: Any DATA chunks that were sent to the address for 5593 * which the T3-rtx timer expired but did not fit in one MTU 5594 * (rule E3 above), should be marked for retransmission and 5595 * sent as soon as cwnd allows (normally when a SACK arrives). 5596 */ 5597 5598 /* Do some failure management (Section 8.2). */ 5599 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5600 5601 /* NB: Rules E4 and F1 are implicit in R1. */ 5602 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5603 5604 return SCTP_DISPOSITION_CONSUME; 5605 } 5606 5607 /* 5608 * Generate delayed SACK on timeout 5609 * 5610 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5611 * 5612 * The guidelines on delayed acknowledgement algorithm specified in 5613 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5614 * acknowledgement SHOULD be generated for at least every second packet 5615 * (not every second DATA chunk) received, and SHOULD be generated 5616 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5617 * some situations it may be beneficial for an SCTP transmitter to be 5618 * more conservative than the algorithms detailed in this document 5619 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5620 * the following algorithms allow. 5621 */ 5622 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5623 const struct sctp_endpoint *ep, 5624 const struct sctp_association *asoc, 5625 const union sctp_subtype type, 5626 void *arg, 5627 struct sctp_cmd_seq *commands) 5628 { 5629 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5630 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5631 return SCTP_DISPOSITION_CONSUME; 5632 } 5633 5634 /* 5635 * sctp_sf_t1_init_timer_expire 5636 * 5637 * Section: 4 Note: 2 5638 * Verification Tag: 5639 * Inputs 5640 * (endpoint, asoc) 5641 * 5642 * RFC 2960 Section 4 Notes 5643 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5644 * and re-start the T1-init timer without changing state. This MUST 5645 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5646 * endpoint MUST abort the initialization process and report the 5647 * error to SCTP user. 5648 * 5649 * Outputs 5650 * (timers, events) 5651 * 5652 */ 5653 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5654 struct net *net, 5655 const struct sctp_endpoint *ep, 5656 const struct sctp_association *asoc, 5657 const union sctp_subtype type, 5658 void *arg, 5659 struct sctp_cmd_seq *commands) 5660 { 5661 int attempts = asoc->init_err_counter + 1; 5662 struct sctp_chunk *repl = NULL; 5663 struct sctp_bind_addr *bp; 5664 5665 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5666 5667 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5668 5669 if (attempts <= asoc->max_init_attempts) { 5670 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5671 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5672 if (!repl) 5673 return SCTP_DISPOSITION_NOMEM; 5674 5675 /* Choose transport for INIT. */ 5676 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5677 SCTP_CHUNK(repl)); 5678 5679 /* Issue a sideeffect to do the needed accounting. */ 5680 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5681 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5682 5683 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5684 } else { 5685 pr_debug("%s: giving up on INIT, attempts:%d " 5686 "max_init_attempts:%d\n", __func__, attempts, 5687 asoc->max_init_attempts); 5688 5689 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5690 SCTP_ERROR(ETIMEDOUT)); 5691 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5692 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5693 return SCTP_DISPOSITION_DELETE_TCB; 5694 } 5695 5696 return SCTP_DISPOSITION_CONSUME; 5697 } 5698 5699 /* 5700 * sctp_sf_t1_cookie_timer_expire 5701 * 5702 * Section: 4 Note: 2 5703 * Verification Tag: 5704 * Inputs 5705 * (endpoint, asoc) 5706 * 5707 * RFC 2960 Section 4 Notes 5708 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5709 * COOKIE ECHO and re-start the T1-cookie timer without changing 5710 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5711 * After that, the endpoint MUST abort the initialization process and 5712 * report the error to SCTP user. 5713 * 5714 * Outputs 5715 * (timers, events) 5716 * 5717 */ 5718 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5719 struct net *net, 5720 const struct sctp_endpoint *ep, 5721 const struct sctp_association *asoc, 5722 const union sctp_subtype type, 5723 void *arg, 5724 struct sctp_cmd_seq *commands) 5725 { 5726 int attempts = asoc->init_err_counter + 1; 5727 struct sctp_chunk *repl = NULL; 5728 5729 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5730 5731 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5732 5733 if (attempts <= asoc->max_init_attempts) { 5734 repl = sctp_make_cookie_echo(asoc, NULL); 5735 if (!repl) 5736 return SCTP_DISPOSITION_NOMEM; 5737 5738 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5739 SCTP_CHUNK(repl)); 5740 /* Issue a sideeffect to do the needed accounting. */ 5741 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5742 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5743 5744 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5745 } else { 5746 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5747 SCTP_ERROR(ETIMEDOUT)); 5748 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5749 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5750 return SCTP_DISPOSITION_DELETE_TCB; 5751 } 5752 5753 return SCTP_DISPOSITION_CONSUME; 5754 } 5755 5756 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5757 * with the updated last sequential TSN received from its peer. 5758 * 5759 * An endpoint should limit the number of retransmissions of the 5760 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5761 * If this threshold is exceeded the endpoint should destroy the TCB and 5762 * MUST report the peer endpoint unreachable to the upper layer (and 5763 * thus the association enters the CLOSED state). The reception of any 5764 * packet from its peer (i.e. as the peer sends all of its queued DATA 5765 * chunks) should clear the endpoint's retransmission count and restart 5766 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5767 * all of its queued DATA chunks that have not yet been sent. 5768 */ 5769 enum sctp_disposition sctp_sf_t2_timer_expire( 5770 struct net *net, 5771 const struct sctp_endpoint *ep, 5772 const struct sctp_association *asoc, 5773 const union sctp_subtype type, 5774 void *arg, 5775 struct sctp_cmd_seq *commands) 5776 { 5777 struct sctp_chunk *reply = NULL; 5778 5779 pr_debug("%s: timer T2 expired\n", __func__); 5780 5781 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5782 5783 ((struct sctp_association *)asoc)->shutdown_retries++; 5784 5785 if (asoc->overall_error_count >= asoc->max_retrans) { 5786 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5787 SCTP_ERROR(ETIMEDOUT)); 5788 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5789 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5790 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5791 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5792 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5793 return SCTP_DISPOSITION_DELETE_TCB; 5794 } 5795 5796 switch (asoc->state) { 5797 case SCTP_STATE_SHUTDOWN_SENT: 5798 reply = sctp_make_shutdown(asoc, NULL); 5799 break; 5800 5801 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5802 reply = sctp_make_shutdown_ack(asoc, NULL); 5803 break; 5804 5805 default: 5806 BUG(); 5807 break; 5808 } 5809 5810 if (!reply) 5811 goto nomem; 5812 5813 /* Do some failure management (Section 8.2). 5814 * If we remove the transport an SHUTDOWN was last sent to, don't 5815 * do failure management. 5816 */ 5817 if (asoc->shutdown_last_sent_to) 5818 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5819 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5820 5821 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5822 * the T2-shutdown timer. 5823 */ 5824 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5825 5826 /* Restart the T2-shutdown timer. */ 5827 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5828 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5829 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5830 return SCTP_DISPOSITION_CONSUME; 5831 5832 nomem: 5833 return SCTP_DISPOSITION_NOMEM; 5834 } 5835 5836 /* 5837 * ADDIP Section 4.1 ASCONF CHunk Procedures 5838 * If the T4 RTO timer expires the endpoint should do B1 to B5 5839 */ 5840 enum sctp_disposition sctp_sf_t4_timer_expire( 5841 struct net *net, 5842 const struct sctp_endpoint *ep, 5843 const struct sctp_association *asoc, 5844 const union sctp_subtype type, 5845 void *arg, 5846 struct sctp_cmd_seq *commands) 5847 { 5848 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5849 struct sctp_transport *transport = chunk->transport; 5850 5851 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5852 5853 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5854 * detection on the appropriate destination address as defined in 5855 * RFC2960 [5] section 8.1 and 8.2. 5856 */ 5857 if (transport) 5858 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5859 SCTP_TRANSPORT(transport)); 5860 5861 /* Reconfig T4 timer and transport. */ 5862 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5863 5864 /* ADDIP 4.1 B2) Increment the association error counters and perform 5865 * endpoint failure detection on the association as defined in 5866 * RFC2960 [5] section 8.1 and 8.2. 5867 * association error counter is incremented in SCTP_CMD_STRIKE. 5868 */ 5869 if (asoc->overall_error_count >= asoc->max_retrans) { 5870 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5871 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5872 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5873 SCTP_ERROR(ETIMEDOUT)); 5874 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5875 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5876 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5877 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5878 return SCTP_DISPOSITION_ABORT; 5879 } 5880 5881 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5882 * the ASCONF chunk was sent by doubling the RTO timer value. 5883 * This is done in SCTP_CMD_STRIKE. 5884 */ 5885 5886 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5887 * choose an alternate destination address (please refer to RFC2960 5888 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5889 * chunk, it MUST be the same (including its serial number) as the last 5890 * ASCONF sent. 5891 */ 5892 sctp_chunk_hold(asoc->addip_last_asconf); 5893 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5894 SCTP_CHUNK(asoc->addip_last_asconf)); 5895 5896 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5897 * destination is selected, then the RTO used will be that of the new 5898 * destination address. 5899 */ 5900 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5901 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5902 5903 return SCTP_DISPOSITION_CONSUME; 5904 } 5905 5906 /* sctpimpguide-05 Section 2.12.2 5907 * The sender of the SHUTDOWN MAY also start an overall guard timer 5908 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5909 * At the expiration of this timer the sender SHOULD abort the association 5910 * by sending an ABORT chunk. 5911 */ 5912 enum sctp_disposition sctp_sf_t5_timer_expire( 5913 struct net *net, 5914 const struct sctp_endpoint *ep, 5915 const struct sctp_association *asoc, 5916 const union sctp_subtype type, 5917 void *arg, 5918 struct sctp_cmd_seq *commands) 5919 { 5920 struct sctp_chunk *reply = NULL; 5921 5922 pr_debug("%s: timer T5 expired\n", __func__); 5923 5924 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5925 5926 reply = sctp_make_abort(asoc, NULL, 0); 5927 if (!reply) 5928 goto nomem; 5929 5930 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5931 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5932 SCTP_ERROR(ETIMEDOUT)); 5933 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5934 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5935 5936 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5937 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5938 5939 return SCTP_DISPOSITION_DELETE_TCB; 5940 nomem: 5941 return SCTP_DISPOSITION_NOMEM; 5942 } 5943 5944 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5945 * the association is automatically closed by starting the shutdown process. 5946 * The work that needs to be done is same as when SHUTDOWN is initiated by 5947 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5948 */ 5949 enum sctp_disposition sctp_sf_autoclose_timer_expire( 5950 struct net *net, 5951 const struct sctp_endpoint *ep, 5952 const struct sctp_association *asoc, 5953 const union sctp_subtype type, 5954 void *arg, 5955 struct sctp_cmd_seq *commands) 5956 { 5957 enum sctp_disposition disposition; 5958 5959 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5960 5961 /* From 9.2 Shutdown of an Association 5962 * Upon receipt of the SHUTDOWN primitive from its upper 5963 * layer, the endpoint enters SHUTDOWN-PENDING state and 5964 * remains there until all outstanding data has been 5965 * acknowledged by its peer. The endpoint accepts no new data 5966 * from its upper layer, but retransmits data to the far end 5967 * if necessary to fill gaps. 5968 */ 5969 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5970 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5971 5972 disposition = SCTP_DISPOSITION_CONSUME; 5973 if (sctp_outq_is_empty(&asoc->outqueue)) { 5974 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5975 arg, commands); 5976 } 5977 5978 return disposition; 5979 } 5980 5981 /***************************************************************************** 5982 * These are sa state functions which could apply to all types of events. 5983 ****************************************************************************/ 5984 5985 /* 5986 * This table entry is not implemented. 5987 * 5988 * Inputs 5989 * (endpoint, asoc, chunk) 5990 * 5991 * The return value is the disposition of the chunk. 5992 */ 5993 enum sctp_disposition sctp_sf_not_impl(struct net *net, 5994 const struct sctp_endpoint *ep, 5995 const struct sctp_association *asoc, 5996 const union sctp_subtype type, 5997 void *arg, struct sctp_cmd_seq *commands) 5998 { 5999 return SCTP_DISPOSITION_NOT_IMPL; 6000 } 6001 6002 /* 6003 * This table entry represents a bug. 6004 * 6005 * Inputs 6006 * (endpoint, asoc, chunk) 6007 * 6008 * The return value is the disposition of the chunk. 6009 */ 6010 enum sctp_disposition sctp_sf_bug(struct net *net, 6011 const struct sctp_endpoint *ep, 6012 const struct sctp_association *asoc, 6013 const union sctp_subtype type, 6014 void *arg, struct sctp_cmd_seq *commands) 6015 { 6016 return SCTP_DISPOSITION_BUG; 6017 } 6018 6019 /* 6020 * This table entry represents the firing of a timer in the wrong state. 6021 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6022 * when the association is in the wrong state. This event should 6023 * be ignored, so as to prevent any rearming of the timer. 6024 * 6025 * Inputs 6026 * (endpoint, asoc, chunk) 6027 * 6028 * The return value is the disposition of the chunk. 6029 */ 6030 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6031 const struct sctp_endpoint *ep, 6032 const struct sctp_association *asoc, 6033 const union sctp_subtype type, 6034 void *arg, 6035 struct sctp_cmd_seq *commands) 6036 { 6037 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6038 6039 return SCTP_DISPOSITION_CONSUME; 6040 } 6041 6042 /******************************************************************** 6043 * 2nd Level Abstractions 6044 ********************************************************************/ 6045 6046 /* Pull the SACK chunk based on the SACK header. */ 6047 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6048 { 6049 struct sctp_sackhdr *sack; 6050 __u16 num_dup_tsns; 6051 unsigned int len; 6052 __u16 num_blocks; 6053 6054 /* Protect ourselves from reading too far into 6055 * the skb from a bogus sender. 6056 */ 6057 sack = (struct sctp_sackhdr *) chunk->skb->data; 6058 6059 num_blocks = ntohs(sack->num_gap_ack_blocks); 6060 num_dup_tsns = ntohs(sack->num_dup_tsns); 6061 len = sizeof(struct sctp_sackhdr); 6062 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6063 if (len > chunk->skb->len) 6064 return NULL; 6065 6066 skb_pull(chunk->skb, len); 6067 6068 return sack; 6069 } 6070 6071 /* Create an ABORT packet to be sent as a response, with the specified 6072 * error causes. 6073 */ 6074 static struct sctp_packet *sctp_abort_pkt_new( 6075 struct net *net, 6076 const struct sctp_endpoint *ep, 6077 const struct sctp_association *asoc, 6078 struct sctp_chunk *chunk, 6079 const void *payload, size_t paylen) 6080 { 6081 struct sctp_packet *packet; 6082 struct sctp_chunk *abort; 6083 6084 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6085 6086 if (packet) { 6087 /* Make an ABORT. 6088 * The T bit will be set if the asoc is NULL. 6089 */ 6090 abort = sctp_make_abort(asoc, chunk, paylen); 6091 if (!abort) { 6092 sctp_ootb_pkt_free(packet); 6093 return NULL; 6094 } 6095 6096 /* Reflect vtag if T-Bit is set */ 6097 if (sctp_test_T_bit(abort)) 6098 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6099 6100 /* Add specified error causes, i.e., payload, to the 6101 * end of the chunk. 6102 */ 6103 sctp_addto_chunk(abort, paylen, payload); 6104 6105 /* Set the skb to the belonging sock for accounting. */ 6106 abort->skb->sk = ep->base.sk; 6107 6108 sctp_packet_append_chunk(packet, abort); 6109 6110 } 6111 6112 return packet; 6113 } 6114 6115 /* Allocate a packet for responding in the OOTB conditions. */ 6116 static struct sctp_packet *sctp_ootb_pkt_new( 6117 struct net *net, 6118 const struct sctp_association *asoc, 6119 const struct sctp_chunk *chunk) 6120 { 6121 struct sctp_transport *transport; 6122 struct sctp_packet *packet; 6123 __u16 sport, dport; 6124 __u32 vtag; 6125 6126 /* Get the source and destination port from the inbound packet. */ 6127 sport = ntohs(chunk->sctp_hdr->dest); 6128 dport = ntohs(chunk->sctp_hdr->source); 6129 6130 /* The V-tag is going to be the same as the inbound packet if no 6131 * association exists, otherwise, use the peer's vtag. 6132 */ 6133 if (asoc) { 6134 /* Special case the INIT-ACK as there is no peer's vtag 6135 * yet. 6136 */ 6137 switch (chunk->chunk_hdr->type) { 6138 case SCTP_CID_INIT_ACK: 6139 { 6140 struct sctp_initack_chunk *initack; 6141 6142 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6143 vtag = ntohl(initack->init_hdr.init_tag); 6144 break; 6145 } 6146 default: 6147 vtag = asoc->peer.i.init_tag; 6148 break; 6149 } 6150 } else { 6151 /* Special case the INIT and stale COOKIE_ECHO as there is no 6152 * vtag yet. 6153 */ 6154 switch (chunk->chunk_hdr->type) { 6155 case SCTP_CID_INIT: 6156 { 6157 struct sctp_init_chunk *init; 6158 6159 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6160 vtag = ntohl(init->init_hdr.init_tag); 6161 break; 6162 } 6163 default: 6164 vtag = ntohl(chunk->sctp_hdr->vtag); 6165 break; 6166 } 6167 } 6168 6169 /* Make a transport for the bucket, Eliza... */ 6170 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6171 if (!transport) 6172 goto nomem; 6173 6174 /* Cache a route for the transport with the chunk's destination as 6175 * the source address. 6176 */ 6177 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6178 sctp_sk(net->sctp.ctl_sock)); 6179 6180 packet = &transport->packet; 6181 sctp_packet_init(packet, transport, sport, dport); 6182 sctp_packet_config(packet, vtag, 0); 6183 6184 return packet; 6185 6186 nomem: 6187 return NULL; 6188 } 6189 6190 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6191 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6192 { 6193 sctp_transport_free(packet->transport); 6194 } 6195 6196 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6197 static void sctp_send_stale_cookie_err(struct net *net, 6198 const struct sctp_endpoint *ep, 6199 const struct sctp_association *asoc, 6200 const struct sctp_chunk *chunk, 6201 struct sctp_cmd_seq *commands, 6202 struct sctp_chunk *err_chunk) 6203 { 6204 struct sctp_packet *packet; 6205 6206 if (err_chunk) { 6207 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6208 if (packet) { 6209 struct sctp_signed_cookie *cookie; 6210 6211 /* Override the OOTB vtag from the cookie. */ 6212 cookie = chunk->subh.cookie_hdr; 6213 packet->vtag = cookie->c.peer_vtag; 6214 6215 /* Set the skb to the belonging sock for accounting. */ 6216 err_chunk->skb->sk = ep->base.sk; 6217 sctp_packet_append_chunk(packet, err_chunk); 6218 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6219 SCTP_PACKET(packet)); 6220 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6221 } else 6222 sctp_chunk_free (err_chunk); 6223 } 6224 } 6225 6226 6227 /* Process a data chunk */ 6228 static int sctp_eat_data(const struct sctp_association *asoc, 6229 struct sctp_chunk *chunk, 6230 struct sctp_cmd_seq *commands) 6231 { 6232 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6233 struct sock *sk = asoc->base.sk; 6234 struct net *net = sock_net(sk); 6235 struct sctp_datahdr *data_hdr; 6236 struct sctp_chunk *err; 6237 enum sctp_verb deliver; 6238 size_t datalen; 6239 __u32 tsn; 6240 int tmp; 6241 6242 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6243 chunk->subh.data_hdr = data_hdr; 6244 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6245 6246 tsn = ntohl(data_hdr->tsn); 6247 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6248 6249 /* ASSERT: Now skb->data is really the user data. */ 6250 6251 /* Process ECN based congestion. 6252 * 6253 * Since the chunk structure is reused for all chunks within 6254 * a packet, we use ecn_ce_done to track if we've already 6255 * done CE processing for this packet. 6256 * 6257 * We need to do ECN processing even if we plan to discard the 6258 * chunk later. 6259 */ 6260 6261 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6262 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6263 chunk->ecn_ce_done = 1; 6264 6265 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6266 /* Do real work as sideffect. */ 6267 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6268 SCTP_U32(tsn)); 6269 } 6270 } 6271 6272 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6273 if (tmp < 0) { 6274 /* The TSN is too high--silently discard the chunk and 6275 * count on it getting retransmitted later. 6276 */ 6277 if (chunk->asoc) 6278 chunk->asoc->stats.outofseqtsns++; 6279 return SCTP_IERROR_HIGH_TSN; 6280 } else if (tmp > 0) { 6281 /* This is a duplicate. Record it. */ 6282 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6283 return SCTP_IERROR_DUP_TSN; 6284 } 6285 6286 /* This is a new TSN. */ 6287 6288 /* Discard if there is no room in the receive window. 6289 * Actually, allow a little bit of overflow (up to a MTU). 6290 */ 6291 datalen = ntohs(chunk->chunk_hdr->length); 6292 datalen -= sctp_datachk_len(&asoc->stream); 6293 6294 deliver = SCTP_CMD_CHUNK_ULP; 6295 6296 /* Think about partial delivery. */ 6297 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6298 6299 /* Even if we don't accept this chunk there is 6300 * memory pressure. 6301 */ 6302 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6303 } 6304 6305 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6306 * seems a bit troublesome in that frag_point varies based on 6307 * PMTU. In cases, such as loopback, this might be a rather 6308 * large spill over. 6309 */ 6310 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6311 (datalen > asoc->rwnd + asoc->frag_point))) { 6312 6313 /* If this is the next TSN, consider reneging to make 6314 * room. Note: Playing nice with a confused sender. A 6315 * malicious sender can still eat up all our buffer 6316 * space and in the future we may want to detect and 6317 * do more drastic reneging. 6318 */ 6319 if (sctp_tsnmap_has_gap(map) && 6320 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6321 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6322 deliver = SCTP_CMD_RENEGE; 6323 } else { 6324 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6325 __func__, tsn, datalen, asoc->rwnd); 6326 6327 return SCTP_IERROR_IGNORE_TSN; 6328 } 6329 } 6330 6331 /* 6332 * Also try to renege to limit our memory usage in the event that 6333 * we are under memory pressure 6334 * If we can't renege, don't worry about it, the sk_rmem_schedule 6335 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6336 * memory usage too much 6337 */ 6338 if (*sk->sk_prot_creator->memory_pressure) { 6339 if (sctp_tsnmap_has_gap(map) && 6340 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6341 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6342 __func__, tsn); 6343 deliver = SCTP_CMD_RENEGE; 6344 } 6345 } 6346 6347 /* 6348 * Section 3.3.10.9 No User Data (9) 6349 * 6350 * Cause of error 6351 * --------------- 6352 * No User Data: This error cause is returned to the originator of a 6353 * DATA chunk if a received DATA chunk has no user data. 6354 */ 6355 if (unlikely(0 == datalen)) { 6356 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6357 if (err) { 6358 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6359 SCTP_CHUNK(err)); 6360 } 6361 /* We are going to ABORT, so we might as well stop 6362 * processing the rest of the chunks in the packet. 6363 */ 6364 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6365 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6366 SCTP_ERROR(ECONNABORTED)); 6367 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6368 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6369 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6370 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6371 return SCTP_IERROR_NO_DATA; 6372 } 6373 6374 chunk->data_accepted = 1; 6375 6376 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6377 * if we renege and the chunk arrives again. 6378 */ 6379 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6380 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6381 if (chunk->asoc) 6382 chunk->asoc->stats.iuodchunks++; 6383 } else { 6384 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6385 if (chunk->asoc) 6386 chunk->asoc->stats.iodchunks++; 6387 } 6388 6389 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6390 * 6391 * If an endpoint receive a DATA chunk with an invalid stream 6392 * identifier, it shall acknowledge the reception of the DATA chunk 6393 * following the normal procedure, immediately send an ERROR chunk 6394 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6395 * and discard the DATA chunk. 6396 */ 6397 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6398 /* Mark tsn as received even though we drop it */ 6399 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6400 6401 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6402 &data_hdr->stream, 6403 sizeof(data_hdr->stream), 6404 sizeof(u16)); 6405 if (err) 6406 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6407 SCTP_CHUNK(err)); 6408 return SCTP_IERROR_BAD_STREAM; 6409 } 6410 6411 /* Check to see if the SSN is possible for this TSN. 6412 * The biggest gap we can record is 4K wide. Since SSNs wrap 6413 * at an unsigned short, there is no way that an SSN can 6414 * wrap and for a valid TSN. We can simply check if the current 6415 * SSN is smaller then the next expected one. If it is, it wrapped 6416 * and is invalid. 6417 */ 6418 if (!asoc->stream.si->validate_data(chunk)) 6419 return SCTP_IERROR_PROTO_VIOLATION; 6420 6421 /* Send the data up to the user. Note: Schedule the 6422 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6423 * chunk needs the updated rwnd. 6424 */ 6425 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6426 6427 return SCTP_IERROR_NO_ERROR; 6428 } 6429