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 #define CREATE_TRACE_POINTS 63 #include <trace/events/sctp.h> 64 65 static struct sctp_packet *sctp_abort_pkt_new( 66 struct net *net, 67 const struct sctp_endpoint *ep, 68 const struct sctp_association *asoc, 69 struct sctp_chunk *chunk, 70 const void *payload, size_t paylen); 71 static int sctp_eat_data(const struct sctp_association *asoc, 72 struct sctp_chunk *chunk, 73 struct sctp_cmd_seq *commands); 74 static struct sctp_packet *sctp_ootb_pkt_new( 75 struct net *net, 76 const struct sctp_association *asoc, 77 const struct sctp_chunk *chunk); 78 static void sctp_send_stale_cookie_err(struct net *net, 79 const struct sctp_endpoint *ep, 80 const struct sctp_association *asoc, 81 const struct sctp_chunk *chunk, 82 struct sctp_cmd_seq *commands, 83 struct sctp_chunk *err_chunk); 84 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 85 struct net *net, 86 const struct sctp_endpoint *ep, 87 const struct sctp_association *asoc, 88 const union sctp_subtype type, 89 void *arg, 90 struct sctp_cmd_seq *commands); 91 static enum sctp_disposition sctp_sf_shut_8_4_5( 92 struct net *net, 93 const struct sctp_endpoint *ep, 94 const struct sctp_association *asoc, 95 const union sctp_subtype type, 96 void *arg, 97 struct sctp_cmd_seq *commands); 98 static enum sctp_disposition sctp_sf_tabort_8_4_8( 99 struct net *net, 100 const struct sctp_endpoint *ep, 101 const struct sctp_association *asoc, 102 const union sctp_subtype type, 103 void *arg, 104 struct sctp_cmd_seq *commands); 105 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 106 107 static enum sctp_disposition sctp_stop_t1_and_abort( 108 struct net *net, 109 struct sctp_cmd_seq *commands, 110 __be16 error, int sk_err, 111 const struct sctp_association *asoc, 112 struct sctp_transport *transport); 113 114 static enum sctp_disposition sctp_sf_abort_violation( 115 struct net *net, 116 const struct sctp_endpoint *ep, 117 const struct sctp_association *asoc, 118 void *arg, 119 struct sctp_cmd_seq *commands, 120 const __u8 *payload, 121 const size_t paylen); 122 123 static enum sctp_disposition sctp_sf_violation_chunklen( 124 struct net *net, 125 const struct sctp_endpoint *ep, 126 const struct sctp_association *asoc, 127 const union sctp_subtype type, 128 void *arg, 129 struct sctp_cmd_seq *commands); 130 131 static enum sctp_disposition sctp_sf_violation_paramlen( 132 struct net *net, 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const union sctp_subtype type, 136 void *arg, void *ext, 137 struct sctp_cmd_seq *commands); 138 139 static enum sctp_disposition sctp_sf_violation_ctsn( 140 struct net *net, 141 const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const union sctp_subtype type, 144 void *arg, 145 struct sctp_cmd_seq *commands); 146 147 static enum sctp_disposition sctp_sf_violation_chunk( 148 struct net *net, 149 const struct sctp_endpoint *ep, 150 const struct sctp_association *asoc, 151 const union sctp_subtype type, 152 void *arg, 153 struct sctp_cmd_seq *commands); 154 155 static enum sctp_ierror sctp_sf_authenticate( 156 struct net *net, 157 const struct sctp_endpoint *ep, 158 const struct sctp_association *asoc, 159 const union sctp_subtype type, 160 struct sctp_chunk *chunk); 161 162 static enum sctp_disposition __sctp_sf_do_9_1_abort( 163 struct net *net, 164 const struct sctp_endpoint *ep, 165 const struct sctp_association *asoc, 166 const union sctp_subtype type, 167 void *arg, 168 struct sctp_cmd_seq *commands); 169 170 /* Small helper function that checks if the chunk length 171 * is of the appropriate length. The 'required_length' argument 172 * is set to be the size of a specific chunk we are testing. 173 * Return Values: true = Valid length 174 * false = Invalid length 175 * 176 */ 177 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 178 __u16 required_length) 179 { 180 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 181 182 /* Previously already marked? */ 183 if (unlikely(chunk->pdiscard)) 184 return false; 185 if (unlikely(chunk_length < required_length)) 186 return false; 187 188 return true; 189 } 190 191 /********************************************************** 192 * These are the state functions for handling chunk events. 193 **********************************************************/ 194 195 /* 196 * Process the final SHUTDOWN COMPLETE. 197 * 198 * Section: 4 (C) (diagram), 9.2 199 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 200 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 201 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 202 * should stop the T2-shutdown timer and remove all knowledge of the 203 * association (and thus the association enters the CLOSED state). 204 * 205 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 206 * C) Rules for packet carrying SHUTDOWN COMPLETE: 207 * ... 208 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 209 * if the Verification Tag field of the packet matches its own tag and 210 * the T bit is not set 211 * OR 212 * it is set to its peer's tag and the T bit is set in the Chunk 213 * Flags. 214 * Otherwise, the receiver MUST silently discard the packet 215 * and take no further action. An endpoint MUST ignore the 216 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 217 * 218 * Inputs 219 * (endpoint, asoc, chunk) 220 * 221 * Outputs 222 * (asoc, reply_msg, msg_up, timers, counters) 223 * 224 * The return value is the disposition of the chunk. 225 */ 226 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 227 const struct sctp_endpoint *ep, 228 const struct sctp_association *asoc, 229 const union sctp_subtype type, 230 void *arg, struct sctp_cmd_seq *commands) 231 { 232 struct sctp_chunk *chunk = arg; 233 struct sctp_ulpevent *ev; 234 235 if (!sctp_vtag_verify_either(chunk, asoc)) 236 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 237 238 /* RFC 2960 6.10 Bundling 239 * 240 * An endpoint MUST NOT bundle INIT, INIT ACK or 241 * SHUTDOWN COMPLETE with any other chunks. 242 */ 243 if (!chunk->singleton) 244 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 245 246 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 247 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 248 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 249 commands); 250 251 /* RFC 2960 10.2 SCTP-to-ULP 252 * 253 * H) SHUTDOWN COMPLETE notification 254 * 255 * When SCTP completes the shutdown procedures (section 9.2) this 256 * notification is passed to the upper layer. 257 */ 258 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 259 0, 0, 0, NULL, GFP_ATOMIC); 260 if (ev) 261 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 262 SCTP_ULPEVENT(ev)); 263 264 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 265 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 266 * not the chunk should be discarded. If the endpoint is in 267 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 268 * T2-shutdown timer and remove all knowledge of the 269 * association (and thus the association enters the CLOSED 270 * state). 271 */ 272 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 273 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 274 275 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 276 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 277 278 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 279 SCTP_STATE(SCTP_STATE_CLOSED)); 280 281 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 282 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 283 284 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 285 286 return SCTP_DISPOSITION_DELETE_TCB; 287 } 288 289 /* 290 * Respond to a normal INIT chunk. 291 * We are the side that is being asked for an association. 292 * 293 * Section: 5.1 Normal Establishment of an Association, B 294 * B) "Z" shall respond immediately with an INIT ACK chunk. The 295 * destination IP address of the INIT ACK MUST be set to the source 296 * IP address of the INIT to which this INIT ACK is responding. In 297 * the response, besides filling in other parameters, "Z" must set the 298 * Verification Tag field to Tag_A, and also provide its own 299 * Verification Tag (Tag_Z) in the Initiate Tag field. 300 * 301 * Verification Tag: Must be 0. 302 * 303 * Inputs 304 * (endpoint, asoc, chunk) 305 * 306 * Outputs 307 * (asoc, reply_msg, msg_up, timers, counters) 308 * 309 * The return value is the disposition of the chunk. 310 */ 311 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 312 const struct sctp_endpoint *ep, 313 const struct sctp_association *asoc, 314 const union sctp_subtype type, 315 void *arg, 316 struct sctp_cmd_seq *commands) 317 { 318 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 319 struct sctp_unrecognized_param *unk_param; 320 struct sctp_association *new_asoc; 321 struct sctp_packet *packet; 322 int len; 323 324 /* 6.10 Bundling 325 * An endpoint MUST NOT bundle INIT, INIT ACK or 326 * SHUTDOWN COMPLETE with any other chunks. 327 * 328 * IG Section 2.11.2 329 * Furthermore, we require that the receiver of an INIT chunk MUST 330 * enforce these rules by silently discarding an arriving packet 331 * with an INIT chunk that is bundled with other chunks. 332 */ 333 if (!chunk->singleton) 334 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 335 336 /* If the packet is an OOTB packet which is temporarily on the 337 * control endpoint, respond with an ABORT. 338 */ 339 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 340 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 341 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 342 } 343 344 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 345 * Tag. 346 */ 347 if (chunk->sctp_hdr->vtag != 0) 348 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 349 350 /* Make sure that the INIT chunk has a valid length. 351 * Normally, this would cause an ABORT with a Protocol Violation 352 * error, but since we don't have an association, we'll 353 * just discard the packet. 354 */ 355 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 356 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 357 358 /* If the INIT is coming toward a closing socket, we'll send back 359 * and ABORT. Essentially, this catches the race of INIT being 360 * backloged to the socket at the same time as the user isses close(). 361 * Since the socket and all its associations are going away, we 362 * can treat this OOTB 363 */ 364 if (sctp_sstate(ep->base.sk, CLOSING)) 365 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 366 367 /* Verify the INIT chunk before processing it. */ 368 err_chunk = NULL; 369 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 370 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 371 &err_chunk)) { 372 /* This chunk contains fatal error. It is to be discarded. 373 * Send an ABORT, with causes if there is any. 374 */ 375 if (err_chunk) { 376 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 377 (__u8 *)(err_chunk->chunk_hdr) + 378 sizeof(struct sctp_chunkhdr), 379 ntohs(err_chunk->chunk_hdr->length) - 380 sizeof(struct sctp_chunkhdr)); 381 382 sctp_chunk_free(err_chunk); 383 384 if (packet) { 385 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 386 SCTP_PACKET(packet)); 387 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 388 return SCTP_DISPOSITION_CONSUME; 389 } else { 390 return SCTP_DISPOSITION_NOMEM; 391 } 392 } else { 393 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 394 commands); 395 } 396 } 397 398 /* Grab the INIT header. */ 399 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 400 401 /* Tag the variable length parameters. */ 402 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 403 404 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 405 if (!new_asoc) 406 goto nomem; 407 408 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 409 sctp_scope(sctp_source(chunk)), 410 GFP_ATOMIC) < 0) 411 goto nomem_init; 412 413 /* The call, sctp_process_init(), can fail on memory allocation. */ 414 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 415 (struct sctp_init_chunk *)chunk->chunk_hdr, 416 GFP_ATOMIC)) 417 goto nomem_init; 418 419 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 420 421 /* If there are errors need to be reported for unknown parameters, 422 * make sure to reserve enough room in the INIT ACK for them. 423 */ 424 len = 0; 425 if (err_chunk) 426 len = ntohs(err_chunk->chunk_hdr->length) - 427 sizeof(struct sctp_chunkhdr); 428 429 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 430 if (!repl) 431 goto nomem_init; 432 433 /* If there are errors need to be reported for unknown parameters, 434 * include them in the outgoing INIT ACK as "Unrecognized parameter" 435 * parameter. 436 */ 437 if (err_chunk) { 438 /* Get the "Unrecognized parameter" parameter(s) out of the 439 * ERROR chunk generated by sctp_verify_init(). Since the 440 * error cause code for "unknown parameter" and the 441 * "Unrecognized parameter" type is the same, we can 442 * construct the parameters in INIT ACK by copying the 443 * ERROR causes over. 444 */ 445 unk_param = (struct sctp_unrecognized_param *) 446 ((__u8 *)(err_chunk->chunk_hdr) + 447 sizeof(struct sctp_chunkhdr)); 448 /* Replace the cause code with the "Unrecognized parameter" 449 * parameter type. 450 */ 451 sctp_addto_chunk(repl, len, unk_param); 452 sctp_chunk_free(err_chunk); 453 } 454 455 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 456 457 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 458 459 /* 460 * Note: After sending out INIT ACK with the State Cookie parameter, 461 * "Z" MUST NOT allocate any resources, nor keep any states for the 462 * new association. Otherwise, "Z" will be vulnerable to resource 463 * attacks. 464 */ 465 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 466 467 return SCTP_DISPOSITION_DELETE_TCB; 468 469 nomem_init: 470 sctp_association_free(new_asoc); 471 nomem: 472 if (err_chunk) 473 sctp_chunk_free(err_chunk); 474 return SCTP_DISPOSITION_NOMEM; 475 } 476 477 /* 478 * Respond to a normal INIT ACK chunk. 479 * We are the side that is initiating the association. 480 * 481 * Section: 5.1 Normal Establishment of an Association, C 482 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 483 * timer and leave COOKIE-WAIT state. "A" shall then send the State 484 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 485 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 486 * 487 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 488 * DATA chunks, but it MUST be the first chunk in the packet and 489 * until the COOKIE ACK is returned the sender MUST NOT send any 490 * other packets to the peer. 491 * 492 * Verification Tag: 3.3.3 493 * If the value of the Initiate Tag in a received INIT ACK chunk is 494 * found to be 0, the receiver MUST treat it as an error and close the 495 * association by transmitting an ABORT. 496 * 497 * Inputs 498 * (endpoint, asoc, chunk) 499 * 500 * Outputs 501 * (asoc, reply_msg, msg_up, timers, counters) 502 * 503 * The return value is the disposition of the chunk. 504 */ 505 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 506 const struct sctp_endpoint *ep, 507 const struct sctp_association *asoc, 508 const union sctp_subtype type, 509 void *arg, 510 struct sctp_cmd_seq *commands) 511 { 512 struct sctp_init_chunk *initchunk; 513 struct sctp_chunk *chunk = arg; 514 struct sctp_chunk *err_chunk; 515 struct sctp_packet *packet; 516 517 if (!sctp_vtag_verify(chunk, asoc)) 518 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 519 520 /* 6.10 Bundling 521 * An endpoint MUST NOT bundle INIT, INIT ACK or 522 * SHUTDOWN COMPLETE with any other chunks. 523 */ 524 if (!chunk->singleton) 525 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 526 527 /* Make sure that the INIT-ACK chunk has a valid length */ 528 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 529 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 530 commands); 531 /* Grab the INIT header. */ 532 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 533 534 /* Verify the INIT chunk before processing it. */ 535 err_chunk = NULL; 536 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 537 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 538 &err_chunk)) { 539 540 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 541 542 /* This chunk contains fatal error. It is to be discarded. 543 * Send an ABORT, with causes. If there are no causes, 544 * then there wasn't enough memory. Just terminate 545 * the association. 546 */ 547 if (err_chunk) { 548 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 549 (__u8 *)(err_chunk->chunk_hdr) + 550 sizeof(struct sctp_chunkhdr), 551 ntohs(err_chunk->chunk_hdr->length) - 552 sizeof(struct sctp_chunkhdr)); 553 554 sctp_chunk_free(err_chunk); 555 556 if (packet) { 557 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 558 SCTP_PACKET(packet)); 559 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 560 error = SCTP_ERROR_INV_PARAM; 561 } 562 } 563 564 /* SCTP-AUTH, Section 6.3: 565 * It should be noted that if the receiver wants to tear 566 * down an association in an authenticated way only, the 567 * handling of malformed packets should not result in 568 * tearing down the association. 569 * 570 * This means that if we only want to abort associations 571 * in an authenticated way (i.e AUTH+ABORT), then we 572 * can't destroy this association just because the packet 573 * was malformed. 574 */ 575 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 576 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 577 578 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 579 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 580 asoc, chunk->transport); 581 } 582 583 /* Tag the variable length parameters. Note that we never 584 * convert the parameters in an INIT chunk. 585 */ 586 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 587 588 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 589 590 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 591 SCTP_PEER_INIT(initchunk)); 592 593 /* Reset init error count upon receipt of INIT-ACK. */ 594 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 595 596 /* 5.1 C) "A" shall stop the T1-init timer and leave 597 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 598 * timer, and enter the COOKIE-ECHOED state. 599 */ 600 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 601 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 602 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 603 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 604 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 605 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 606 607 /* SCTP-AUTH: genereate the assocition shared keys so that 608 * we can potentially signe the COOKIE-ECHO. 609 */ 610 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 611 612 /* 5.1 C) "A" shall then send the State Cookie received in the 613 * INIT ACK chunk in a COOKIE ECHO chunk, ... 614 */ 615 /* If there is any errors to report, send the ERROR chunk generated 616 * for unknown parameters as well. 617 */ 618 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 619 SCTP_CHUNK(err_chunk)); 620 621 return SCTP_DISPOSITION_CONSUME; 622 } 623 624 /* 625 * Respond to a normal COOKIE ECHO chunk. 626 * We are the side that is being asked for an association. 627 * 628 * Section: 5.1 Normal Establishment of an Association, D 629 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 630 * with a COOKIE ACK chunk after building a TCB and moving to 631 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 632 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 633 * chunk MUST be the first chunk in the packet. 634 * 635 * IMPLEMENTATION NOTE: An implementation may choose to send the 636 * Communication Up notification to the SCTP user upon reception 637 * of a valid COOKIE ECHO chunk. 638 * 639 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 640 * D) Rules for packet carrying a COOKIE ECHO 641 * 642 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 643 * Initial Tag received in the INIT ACK. 644 * 645 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 646 * 647 * Inputs 648 * (endpoint, asoc, chunk) 649 * 650 * Outputs 651 * (asoc, reply_msg, msg_up, timers, counters) 652 * 653 * The return value is the disposition of the chunk. 654 */ 655 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 656 const struct sctp_endpoint *ep, 657 const struct sctp_association *asoc, 658 const union sctp_subtype type, 659 void *arg, 660 struct sctp_cmd_seq *commands) 661 { 662 struct sctp_ulpevent *ev, *ai_ev = NULL; 663 struct sctp_association *new_asoc; 664 struct sctp_init_chunk *peer_init; 665 struct sctp_chunk *chunk = arg; 666 struct sctp_chunk *err_chk_p; 667 struct sctp_chunk *repl; 668 struct sock *sk; 669 int error = 0; 670 671 /* If the packet is an OOTB packet which is temporarily on the 672 * control endpoint, respond with an ABORT. 673 */ 674 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 675 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 676 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 677 } 678 679 /* Make sure that the COOKIE_ECHO chunk has a valid length. 680 * In this case, we check that we have enough for at least a 681 * chunk header. More detailed verification is done 682 * in sctp_unpack_cookie(). 683 */ 684 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 685 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 686 687 /* If the endpoint is not listening or if the number of associations 688 * on the TCP-style socket exceed the max backlog, respond with an 689 * ABORT. 690 */ 691 sk = ep->base.sk; 692 if (!sctp_sstate(sk, LISTENING) || 693 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 694 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 695 696 /* "Decode" the chunk. We have no optional parameters so we 697 * are in good shape. 698 */ 699 chunk->subh.cookie_hdr = 700 (struct sctp_signed_cookie *)chunk->skb->data; 701 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 702 sizeof(struct sctp_chunkhdr))) 703 goto nomem; 704 705 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 706 * "Z" will reply with a COOKIE ACK chunk after building a TCB 707 * and moving to the ESTABLISHED state. 708 */ 709 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 710 &err_chk_p); 711 712 /* FIXME: 713 * If the re-build failed, what is the proper error path 714 * from here? 715 * 716 * [We should abort the association. --piggy] 717 */ 718 if (!new_asoc) { 719 /* FIXME: Several errors are possible. A bad cookie should 720 * be silently discarded, but think about logging it too. 721 */ 722 switch (error) { 723 case -SCTP_IERROR_NOMEM: 724 goto nomem; 725 726 case -SCTP_IERROR_STALE_COOKIE: 727 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 728 err_chk_p); 729 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 730 731 case -SCTP_IERROR_BAD_SIG: 732 default: 733 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 734 } 735 } 736 737 738 /* Delay state machine commands until later. 739 * 740 * Re-build the bind address for the association is done in 741 * the sctp_unpack_cookie() already. 742 */ 743 /* This is a brand-new association, so these are not yet side 744 * effects--it is safe to run them here. 745 */ 746 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 747 748 if (!sctp_process_init(new_asoc, chunk, 749 &chunk->subh.cookie_hdr->c.peer_addr, 750 peer_init, GFP_ATOMIC)) 751 goto nomem_init; 752 753 /* SCTP-AUTH: Now that we've populate required fields in 754 * sctp_process_init, set up the assocaition shared keys as 755 * necessary so that we can potentially authenticate the ACK 756 */ 757 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 758 if (error) 759 goto nomem_init; 760 761 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 762 * is supposed to be authenticated and we have to do delayed 763 * authentication. We've just recreated the association using 764 * the information in the cookie and now it's much easier to 765 * do the authentication. 766 */ 767 if (chunk->auth_chunk) { 768 struct sctp_chunk auth; 769 enum sctp_ierror ret; 770 771 /* Make sure that we and the peer are AUTH capable */ 772 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) { 773 sctp_association_free(new_asoc); 774 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 775 } 776 777 /* set-up our fake chunk so that we can process it */ 778 auth.skb = chunk->auth_chunk; 779 auth.asoc = chunk->asoc; 780 auth.sctp_hdr = chunk->sctp_hdr; 781 auth.chunk_hdr = (struct sctp_chunkhdr *) 782 skb_push(chunk->auth_chunk, 783 sizeof(struct sctp_chunkhdr)); 784 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 785 auth.transport = chunk->transport; 786 787 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 788 if (ret != SCTP_IERROR_NO_ERROR) { 789 sctp_association_free(new_asoc); 790 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 791 } 792 } 793 794 repl = sctp_make_cookie_ack(new_asoc, chunk); 795 if (!repl) 796 goto nomem_init; 797 798 /* RFC 2960 5.1 Normal Establishment of an Association 799 * 800 * D) IMPLEMENTATION NOTE: An implementation may choose to 801 * send the Communication Up notification to the SCTP user 802 * upon reception of a valid COOKIE ECHO chunk. 803 */ 804 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 805 new_asoc->c.sinit_num_ostreams, 806 new_asoc->c.sinit_max_instreams, 807 NULL, GFP_ATOMIC); 808 if (!ev) 809 goto nomem_ev; 810 811 /* Sockets API Draft Section 5.3.1.6 812 * When a peer sends a Adaptation Layer Indication parameter , SCTP 813 * delivers this notification to inform the application that of the 814 * peers requested adaptation layer. 815 */ 816 if (new_asoc->peer.adaptation_ind) { 817 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 818 GFP_ATOMIC); 819 if (!ai_ev) 820 goto nomem_aiev; 821 } 822 823 /* Add all the state machine commands now since we've created 824 * everything. This way we don't introduce memory corruptions 825 * during side-effect processing and correclty count established 826 * associations. 827 */ 828 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 829 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 830 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 831 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 832 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 833 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 834 835 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 836 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 837 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 838 839 /* This will send the COOKIE ACK */ 840 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 841 842 /* Queue the ASSOC_CHANGE event */ 843 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 844 845 /* Send up the Adaptation Layer Indication event */ 846 if (ai_ev) 847 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 848 SCTP_ULPEVENT(ai_ev)); 849 850 return SCTP_DISPOSITION_CONSUME; 851 852 nomem_aiev: 853 sctp_ulpevent_free(ev); 854 nomem_ev: 855 sctp_chunk_free(repl); 856 nomem_init: 857 sctp_association_free(new_asoc); 858 nomem: 859 return SCTP_DISPOSITION_NOMEM; 860 } 861 862 /* 863 * Respond to a normal COOKIE ACK chunk. 864 * We are the side that is asking for an association. 865 * 866 * RFC 2960 5.1 Normal Establishment of an Association 867 * 868 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 869 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 870 * timer. It may also notify its ULP about the successful 871 * establishment of the association with a Communication Up 872 * notification (see Section 10). 873 * 874 * Verification Tag: 875 * Inputs 876 * (endpoint, asoc, chunk) 877 * 878 * Outputs 879 * (asoc, reply_msg, msg_up, timers, counters) 880 * 881 * The return value is the disposition of the chunk. 882 */ 883 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 884 const struct sctp_endpoint *ep, 885 const struct sctp_association *asoc, 886 const union sctp_subtype type, 887 void *arg, 888 struct sctp_cmd_seq *commands) 889 { 890 struct sctp_chunk *chunk = arg; 891 struct sctp_ulpevent *ev; 892 893 if (!sctp_vtag_verify(chunk, asoc)) 894 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 895 896 /* Verify that the chunk length for the COOKIE-ACK is OK. 897 * If we don't do this, any bundled chunks may be junked. 898 */ 899 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 900 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 901 commands); 902 903 /* Reset init error count upon receipt of COOKIE-ACK, 904 * to avoid problems with the managemement of this 905 * counter in stale cookie situations when a transition back 906 * from the COOKIE-ECHOED state to the COOKIE-WAIT 907 * state is performed. 908 */ 909 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 910 911 /* RFC 2960 5.1 Normal Establishment of an Association 912 * 913 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 914 * from the COOKIE-ECHOED state to the ESTABLISHED state, 915 * stopping the T1-cookie timer. 916 */ 917 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 918 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 919 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 920 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 921 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 922 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 923 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 924 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 925 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 926 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 927 928 /* It may also notify its ULP about the successful 929 * establishment of the association with a Communication Up 930 * notification (see Section 10). 931 */ 932 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 933 0, asoc->c.sinit_num_ostreams, 934 asoc->c.sinit_max_instreams, 935 NULL, GFP_ATOMIC); 936 937 if (!ev) 938 goto nomem; 939 940 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 941 942 /* Sockets API Draft Section 5.3.1.6 943 * When a peer sends a Adaptation Layer Indication parameter , SCTP 944 * delivers this notification to inform the application that of the 945 * peers requested adaptation layer. 946 */ 947 if (asoc->peer.adaptation_ind) { 948 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 949 if (!ev) 950 goto nomem; 951 952 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 953 SCTP_ULPEVENT(ev)); 954 } 955 956 return SCTP_DISPOSITION_CONSUME; 957 nomem: 958 return SCTP_DISPOSITION_NOMEM; 959 } 960 961 /* Generate and sendout a heartbeat packet. */ 962 static enum sctp_disposition sctp_sf_heartbeat( 963 const struct sctp_endpoint *ep, 964 const struct sctp_association *asoc, 965 const union sctp_subtype type, 966 void *arg, 967 struct sctp_cmd_seq *commands) 968 { 969 struct sctp_transport *transport = (struct sctp_transport *) arg; 970 struct sctp_chunk *reply; 971 972 /* Send a heartbeat to our peer. */ 973 reply = sctp_make_heartbeat(asoc, transport); 974 if (!reply) 975 return SCTP_DISPOSITION_NOMEM; 976 977 /* Set rto_pending indicating that an RTT measurement 978 * is started with this heartbeat chunk. 979 */ 980 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 981 SCTP_TRANSPORT(transport)); 982 983 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 984 return SCTP_DISPOSITION_CONSUME; 985 } 986 987 /* Generate a HEARTBEAT packet on the given transport. */ 988 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 989 const struct sctp_endpoint *ep, 990 const struct sctp_association *asoc, 991 const union sctp_subtype type, 992 void *arg, 993 struct sctp_cmd_seq *commands) 994 { 995 struct sctp_transport *transport = (struct sctp_transport *) arg; 996 997 if (asoc->overall_error_count >= asoc->max_retrans) { 998 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 999 SCTP_ERROR(ETIMEDOUT)); 1000 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1001 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1002 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1003 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1004 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1005 return SCTP_DISPOSITION_DELETE_TCB; 1006 } 1007 1008 /* Section 3.3.5. 1009 * The Sender-specific Heartbeat Info field should normally include 1010 * information about the sender's current time when this HEARTBEAT 1011 * chunk is sent and the destination transport address to which this 1012 * HEARTBEAT is sent (see Section 8.3). 1013 */ 1014 1015 if (transport->param_flags & SPP_HB_ENABLE) { 1016 if (SCTP_DISPOSITION_NOMEM == 1017 sctp_sf_heartbeat(ep, asoc, type, arg, 1018 commands)) 1019 return SCTP_DISPOSITION_NOMEM; 1020 1021 /* Set transport error counter and association error counter 1022 * when sending heartbeat. 1023 */ 1024 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1025 SCTP_TRANSPORT(transport)); 1026 } 1027 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1028 SCTP_TRANSPORT(transport)); 1029 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1030 SCTP_TRANSPORT(transport)); 1031 1032 return SCTP_DISPOSITION_CONSUME; 1033 } 1034 1035 /* resend asoc strreset_chunk. */ 1036 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1037 const struct sctp_endpoint *ep, 1038 const struct sctp_association *asoc, 1039 const union sctp_subtype type, 1040 void *arg, 1041 struct sctp_cmd_seq *commands) 1042 { 1043 struct sctp_transport *transport = arg; 1044 1045 if (asoc->overall_error_count >= asoc->max_retrans) { 1046 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1047 SCTP_ERROR(ETIMEDOUT)); 1048 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1049 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1050 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1051 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1052 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1053 return SCTP_DISPOSITION_DELETE_TCB; 1054 } 1055 1056 sctp_chunk_hold(asoc->strreset_chunk); 1057 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1058 SCTP_CHUNK(asoc->strreset_chunk)); 1059 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1060 1061 return SCTP_DISPOSITION_CONSUME; 1062 } 1063 1064 /* 1065 * Process an heartbeat request. 1066 * 1067 * Section: 8.3 Path Heartbeat 1068 * The receiver of the HEARTBEAT should immediately respond with a 1069 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1070 * from the received HEARTBEAT chunk. 1071 * 1072 * Verification Tag: 8.5 Verification Tag [Normal verification] 1073 * When receiving an SCTP packet, the endpoint MUST ensure that the 1074 * value in the Verification Tag field of the received SCTP packet 1075 * matches its own Tag. If the received Verification Tag value does not 1076 * match the receiver's own tag value, the receiver shall silently 1077 * discard the packet and shall not process it any further except for 1078 * those cases listed in Section 8.5.1 below. 1079 * 1080 * Inputs 1081 * (endpoint, asoc, chunk) 1082 * 1083 * Outputs 1084 * (asoc, reply_msg, msg_up, timers, counters) 1085 * 1086 * The return value is the disposition of the chunk. 1087 */ 1088 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1089 const struct sctp_endpoint *ep, 1090 const struct sctp_association *asoc, 1091 const union sctp_subtype type, 1092 void *arg, struct sctp_cmd_seq *commands) 1093 { 1094 struct sctp_paramhdr *param_hdr; 1095 struct sctp_chunk *chunk = arg; 1096 struct sctp_chunk *reply; 1097 size_t paylen = 0; 1098 1099 if (!sctp_vtag_verify(chunk, asoc)) 1100 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1101 1102 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1103 if (!sctp_chunk_length_valid(chunk, 1104 sizeof(struct sctp_heartbeat_chunk))) 1105 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1106 commands); 1107 1108 /* 8.3 The receiver of the HEARTBEAT should immediately 1109 * respond with a HEARTBEAT ACK that contains the Heartbeat 1110 * Information field copied from the received HEARTBEAT chunk. 1111 */ 1112 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1113 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1114 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1115 1116 if (ntohs(param_hdr->length) > paylen) 1117 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1118 param_hdr, commands); 1119 1120 if (!pskb_pull(chunk->skb, paylen)) 1121 goto nomem; 1122 1123 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1124 if (!reply) 1125 goto nomem; 1126 1127 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1128 return SCTP_DISPOSITION_CONSUME; 1129 1130 nomem: 1131 return SCTP_DISPOSITION_NOMEM; 1132 } 1133 1134 /* 1135 * Process the returning HEARTBEAT ACK. 1136 * 1137 * Section: 8.3 Path Heartbeat 1138 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1139 * should clear the error counter of the destination transport 1140 * address to which the HEARTBEAT was sent, and mark the destination 1141 * transport address as active if it is not so marked. The endpoint may 1142 * optionally report to the upper layer when an inactive destination 1143 * address is marked as active due to the reception of the latest 1144 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1145 * clear the association overall error count as well (as defined 1146 * in section 8.1). 1147 * 1148 * The receiver of the HEARTBEAT ACK should also perform an RTT 1149 * measurement for that destination transport address using the time 1150 * value carried in the HEARTBEAT ACK chunk. 1151 * 1152 * Verification Tag: 8.5 Verification Tag [Normal verification] 1153 * 1154 * Inputs 1155 * (endpoint, asoc, chunk) 1156 * 1157 * Outputs 1158 * (asoc, reply_msg, msg_up, timers, counters) 1159 * 1160 * The return value is the disposition of the chunk. 1161 */ 1162 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1163 const struct sctp_endpoint *ep, 1164 const struct sctp_association *asoc, 1165 const union sctp_subtype type, 1166 void *arg, 1167 struct sctp_cmd_seq *commands) 1168 { 1169 struct sctp_sender_hb_info *hbinfo; 1170 struct sctp_chunk *chunk = arg; 1171 struct sctp_transport *link; 1172 unsigned long max_interval; 1173 union sctp_addr from_addr; 1174 1175 if (!sctp_vtag_verify(chunk, asoc)) 1176 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1177 1178 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1179 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1180 sizeof(*hbinfo))) 1181 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1182 commands); 1183 1184 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1185 /* Make sure that the length of the parameter is what we expect */ 1186 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1187 return SCTP_DISPOSITION_DISCARD; 1188 1189 from_addr = hbinfo->daddr; 1190 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1191 1192 /* This should never happen, but lets log it if so. */ 1193 if (unlikely(!link)) { 1194 if (from_addr.sa.sa_family == AF_INET6) { 1195 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1196 __func__, 1197 asoc, 1198 &from_addr.v6.sin6_addr); 1199 } else { 1200 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1201 __func__, 1202 asoc, 1203 &from_addr.v4.sin_addr.s_addr); 1204 } 1205 return SCTP_DISPOSITION_DISCARD; 1206 } 1207 1208 /* Validate the 64-bit random nonce. */ 1209 if (hbinfo->hb_nonce != link->hb_nonce) 1210 return SCTP_DISPOSITION_DISCARD; 1211 1212 max_interval = link->hbinterval + link->rto; 1213 1214 /* Check if the timestamp looks valid. */ 1215 if (time_after(hbinfo->sent_at, jiffies) || 1216 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1217 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1218 "for transport:%p\n", __func__, link); 1219 1220 return SCTP_DISPOSITION_DISCARD; 1221 } 1222 1223 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1224 * the HEARTBEAT should clear the error counter of the 1225 * destination transport address to which the HEARTBEAT was 1226 * sent and mark the destination transport address as active if 1227 * it is not so marked. 1228 */ 1229 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1230 1231 return SCTP_DISPOSITION_CONSUME; 1232 } 1233 1234 /* Helper function to send out an abort for the restart 1235 * condition. 1236 */ 1237 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1238 struct sctp_chunk *init, 1239 struct sctp_cmd_seq *commands) 1240 { 1241 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1242 union sctp_addr_param *addrparm; 1243 struct sctp_errhdr *errhdr; 1244 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1245 struct sctp_endpoint *ep; 1246 struct sctp_packet *pkt; 1247 int len; 1248 1249 /* Build the error on the stack. We are way to malloc crazy 1250 * throughout the code today. 1251 */ 1252 errhdr = (struct sctp_errhdr *)buffer; 1253 addrparm = (union sctp_addr_param *)errhdr->variable; 1254 1255 /* Copy into a parm format. */ 1256 len = af->to_addr_param(ssa, addrparm); 1257 len += sizeof(*errhdr); 1258 1259 errhdr->cause = SCTP_ERROR_RESTART; 1260 errhdr->length = htons(len); 1261 1262 /* Assign to the control socket. */ 1263 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1264 1265 /* Association is NULL since this may be a restart attack and we 1266 * want to send back the attacker's vtag. 1267 */ 1268 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1269 1270 if (!pkt) 1271 goto out; 1272 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1273 1274 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1275 1276 /* Discard the rest of the inbound packet. */ 1277 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1278 1279 out: 1280 /* Even if there is no memory, treat as a failure so 1281 * the packet will get dropped. 1282 */ 1283 return 0; 1284 } 1285 1286 static bool list_has_sctp_addr(const struct list_head *list, 1287 union sctp_addr *ipaddr) 1288 { 1289 struct sctp_transport *addr; 1290 1291 list_for_each_entry(addr, list, transports) { 1292 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1293 return true; 1294 } 1295 1296 return false; 1297 } 1298 /* A restart is occurring, check to make sure no new addresses 1299 * are being added as we may be under a takeover attack. 1300 */ 1301 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1302 const struct sctp_association *asoc, 1303 struct sctp_chunk *init, 1304 struct sctp_cmd_seq *commands) 1305 { 1306 struct net *net = sock_net(new_asoc->base.sk); 1307 struct sctp_transport *new_addr; 1308 int ret = 1; 1309 1310 /* Implementor's Guide - Section 5.2.2 1311 * ... 1312 * Before responding the endpoint MUST check to see if the 1313 * unexpected INIT adds new addresses to the association. If new 1314 * addresses are added to the association, the endpoint MUST respond 1315 * with an ABORT.. 1316 */ 1317 1318 /* Search through all current addresses and make sure 1319 * we aren't adding any new ones. 1320 */ 1321 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1322 transports) { 1323 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1324 &new_addr->ipaddr)) { 1325 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1326 commands); 1327 ret = 0; 1328 break; 1329 } 1330 } 1331 1332 /* Return success if all addresses were found. */ 1333 return ret; 1334 } 1335 1336 /* Populate the verification/tie tags based on overlapping INIT 1337 * scenario. 1338 * 1339 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1340 */ 1341 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1342 const struct sctp_association *asoc) 1343 { 1344 switch (asoc->state) { 1345 1346 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1347 1348 case SCTP_STATE_COOKIE_WAIT: 1349 new_asoc->c.my_vtag = asoc->c.my_vtag; 1350 new_asoc->c.my_ttag = asoc->c.my_vtag; 1351 new_asoc->c.peer_ttag = 0; 1352 break; 1353 1354 case SCTP_STATE_COOKIE_ECHOED: 1355 new_asoc->c.my_vtag = asoc->c.my_vtag; 1356 new_asoc->c.my_ttag = asoc->c.my_vtag; 1357 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1358 break; 1359 1360 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1361 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1362 */ 1363 default: 1364 new_asoc->c.my_ttag = asoc->c.my_vtag; 1365 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1366 break; 1367 } 1368 1369 /* Other parameters for the endpoint SHOULD be copied from the 1370 * existing parameters of the association (e.g. number of 1371 * outbound streams) into the INIT ACK and cookie. 1372 */ 1373 new_asoc->rwnd = asoc->rwnd; 1374 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1375 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1376 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1377 } 1378 1379 /* 1380 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1381 * handling action. 1382 * 1383 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1384 * 1385 * Returns value representing action to be taken. These action values 1386 * correspond to Action/Description values in RFC 2960, Table 2. 1387 */ 1388 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1389 const struct sctp_association *asoc) 1390 { 1391 /* In this case, the peer may have restarted. */ 1392 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1393 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1394 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1395 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1396 return 'A'; 1397 1398 /* Collision case B. */ 1399 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1400 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1401 (0 == asoc->c.peer_vtag))) { 1402 return 'B'; 1403 } 1404 1405 /* Collision case D. */ 1406 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1407 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1408 return 'D'; 1409 1410 /* Collision case C. */ 1411 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1412 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1413 (0 == new_asoc->c.my_ttag) && 1414 (0 == new_asoc->c.peer_ttag)) 1415 return 'C'; 1416 1417 /* No match to any of the special cases; discard this packet. */ 1418 return 'E'; 1419 } 1420 1421 /* Common helper routine for both duplicate and simulataneous INIT 1422 * chunk handling. 1423 */ 1424 static enum sctp_disposition sctp_sf_do_unexpected_init( 1425 struct net *net, 1426 const struct sctp_endpoint *ep, 1427 const struct sctp_association *asoc, 1428 const union sctp_subtype type, 1429 void *arg, 1430 struct sctp_cmd_seq *commands) 1431 { 1432 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1433 struct sctp_unrecognized_param *unk_param; 1434 struct sctp_association *new_asoc; 1435 enum sctp_disposition retval; 1436 struct sctp_packet *packet; 1437 int len; 1438 1439 /* 6.10 Bundling 1440 * An endpoint MUST NOT bundle INIT, INIT ACK or 1441 * SHUTDOWN COMPLETE with any other chunks. 1442 * 1443 * IG Section 2.11.2 1444 * Furthermore, we require that the receiver of an INIT chunk MUST 1445 * enforce these rules by silently discarding an arriving packet 1446 * with an INIT chunk that is bundled with other chunks. 1447 */ 1448 if (!chunk->singleton) 1449 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1450 1451 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1452 * Tag. 1453 */ 1454 if (chunk->sctp_hdr->vtag != 0) 1455 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1456 1457 /* Make sure that the INIT chunk has a valid length. 1458 * In this case, we generate a protocol violation since we have 1459 * an association established. 1460 */ 1461 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1462 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1463 commands); 1464 /* Grab the INIT header. */ 1465 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1466 1467 /* Tag the variable length parameters. */ 1468 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1469 1470 /* Verify the INIT chunk before processing it. */ 1471 err_chunk = NULL; 1472 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1473 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1474 &err_chunk)) { 1475 /* This chunk contains fatal error. It is to be discarded. 1476 * Send an ABORT, with causes if there is any. 1477 */ 1478 if (err_chunk) { 1479 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1480 (__u8 *)(err_chunk->chunk_hdr) + 1481 sizeof(struct sctp_chunkhdr), 1482 ntohs(err_chunk->chunk_hdr->length) - 1483 sizeof(struct sctp_chunkhdr)); 1484 1485 if (packet) { 1486 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1487 SCTP_PACKET(packet)); 1488 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1489 retval = SCTP_DISPOSITION_CONSUME; 1490 } else { 1491 retval = SCTP_DISPOSITION_NOMEM; 1492 } 1493 goto cleanup; 1494 } else { 1495 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1496 commands); 1497 } 1498 } 1499 1500 /* 1501 * Other parameters for the endpoint SHOULD be copied from the 1502 * existing parameters of the association (e.g. number of 1503 * outbound streams) into the INIT ACK and cookie. 1504 * FIXME: We are copying parameters from the endpoint not the 1505 * association. 1506 */ 1507 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1508 if (!new_asoc) 1509 goto nomem; 1510 1511 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1512 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1513 goto nomem; 1514 1515 /* In the outbound INIT ACK the endpoint MUST copy its current 1516 * Verification Tag and Peers Verification tag into a reserved 1517 * place (local tie-tag and per tie-tag) within the state cookie. 1518 */ 1519 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1520 (struct sctp_init_chunk *)chunk->chunk_hdr, 1521 GFP_ATOMIC)) 1522 goto nomem; 1523 1524 /* Make sure no new addresses are being added during the 1525 * restart. Do not do this check for COOKIE-WAIT state, 1526 * since there are no peer addresses to check against. 1527 * Upon return an ABORT will have been sent if needed. 1528 */ 1529 if (!sctp_state(asoc, COOKIE_WAIT)) { 1530 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1531 commands)) { 1532 retval = SCTP_DISPOSITION_CONSUME; 1533 goto nomem_retval; 1534 } 1535 } 1536 1537 sctp_tietags_populate(new_asoc, asoc); 1538 1539 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1540 1541 /* If there are errors need to be reported for unknown parameters, 1542 * make sure to reserve enough room in the INIT ACK for them. 1543 */ 1544 len = 0; 1545 if (err_chunk) { 1546 len = ntohs(err_chunk->chunk_hdr->length) - 1547 sizeof(struct sctp_chunkhdr); 1548 } 1549 1550 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1551 if (!repl) 1552 goto nomem; 1553 1554 /* If there are errors need to be reported for unknown parameters, 1555 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1556 * parameter. 1557 */ 1558 if (err_chunk) { 1559 /* Get the "Unrecognized parameter" parameter(s) out of the 1560 * ERROR chunk generated by sctp_verify_init(). Since the 1561 * error cause code for "unknown parameter" and the 1562 * "Unrecognized parameter" type is the same, we can 1563 * construct the parameters in INIT ACK by copying the 1564 * ERROR causes over. 1565 */ 1566 unk_param = (struct sctp_unrecognized_param *) 1567 ((__u8 *)(err_chunk->chunk_hdr) + 1568 sizeof(struct sctp_chunkhdr)); 1569 /* Replace the cause code with the "Unrecognized parameter" 1570 * parameter type. 1571 */ 1572 sctp_addto_chunk(repl, len, unk_param); 1573 } 1574 1575 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1576 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1577 1578 /* 1579 * Note: After sending out INIT ACK with the State Cookie parameter, 1580 * "Z" MUST NOT allocate any resources for this new association. 1581 * Otherwise, "Z" will be vulnerable to resource attacks. 1582 */ 1583 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1584 retval = SCTP_DISPOSITION_CONSUME; 1585 1586 return retval; 1587 1588 nomem: 1589 retval = SCTP_DISPOSITION_NOMEM; 1590 nomem_retval: 1591 if (new_asoc) 1592 sctp_association_free(new_asoc); 1593 cleanup: 1594 if (err_chunk) 1595 sctp_chunk_free(err_chunk); 1596 return retval; 1597 } 1598 1599 /* 1600 * Handle simultaneous INIT. 1601 * This means we started an INIT and then we got an INIT request from 1602 * our peer. 1603 * 1604 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1605 * This usually indicates an initialization collision, i.e., each 1606 * endpoint is attempting, at about the same time, to establish an 1607 * association with the other endpoint. 1608 * 1609 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1610 * endpoint MUST respond with an INIT ACK using the same parameters it 1611 * sent in its original INIT chunk (including its Verification Tag, 1612 * unchanged). These original parameters are combined with those from the 1613 * newly received INIT chunk. The endpoint shall also generate a State 1614 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1615 * INIT to calculate the State Cookie. 1616 * 1617 * After that, the endpoint MUST NOT change its state, the T1-init 1618 * timer shall be left running and the corresponding TCB MUST NOT be 1619 * destroyed. The normal procedures for handling State Cookies when 1620 * a TCB exists will resolve the duplicate INITs to a single association. 1621 * 1622 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1623 * its Tie-Tags with the Tag information of itself and its peer (see 1624 * section 5.2.2 for a description of the Tie-Tags). 1625 * 1626 * Verification Tag: Not explicit, but an INIT can not have a valid 1627 * verification tag, so we skip the check. 1628 * 1629 * Inputs 1630 * (endpoint, asoc, chunk) 1631 * 1632 * Outputs 1633 * (asoc, reply_msg, msg_up, timers, counters) 1634 * 1635 * The return value is the disposition of the chunk. 1636 */ 1637 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1638 struct net *net, 1639 const struct sctp_endpoint *ep, 1640 const struct sctp_association *asoc, 1641 const union sctp_subtype type, 1642 void *arg, 1643 struct sctp_cmd_seq *commands) 1644 { 1645 /* Call helper to do the real work for both simulataneous and 1646 * duplicate INIT chunk handling. 1647 */ 1648 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1649 } 1650 1651 /* 1652 * Handle duplicated INIT messages. These are usually delayed 1653 * restransmissions. 1654 * 1655 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1656 * COOKIE-ECHOED and COOKIE-WAIT 1657 * 1658 * Unless otherwise stated, upon reception of an unexpected INIT for 1659 * this association, the endpoint shall generate an INIT ACK with a 1660 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1661 * current Verification Tag and peer's Verification Tag into a reserved 1662 * place within the state cookie. We shall refer to these locations as 1663 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1664 * containing this INIT ACK MUST carry a Verification Tag value equal to 1665 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1666 * MUST contain a new Initiation Tag (randomly generated see Section 1667 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1668 * existing parameters of the association (e.g. number of outbound 1669 * streams) into the INIT ACK and cookie. 1670 * 1671 * After sending out the INIT ACK, the endpoint shall take no further 1672 * actions, i.e., the existing association, including its current state, 1673 * and the corresponding TCB MUST NOT be changed. 1674 * 1675 * Note: Only when a TCB exists and the association is not in a COOKIE- 1676 * WAIT state are the Tie-Tags populated. For a normal association INIT 1677 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1678 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1679 * State Cookie are populated as specified in section 5.2.1. 1680 * 1681 * Verification Tag: Not specified, but an INIT has no way of knowing 1682 * what the verification tag could be, so we ignore it. 1683 * 1684 * Inputs 1685 * (endpoint, asoc, chunk) 1686 * 1687 * Outputs 1688 * (asoc, reply_msg, msg_up, timers, counters) 1689 * 1690 * The return value is the disposition of the chunk. 1691 */ 1692 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1693 struct net *net, 1694 const struct sctp_endpoint *ep, 1695 const struct sctp_association *asoc, 1696 const union sctp_subtype type, 1697 void *arg, 1698 struct sctp_cmd_seq *commands) 1699 { 1700 /* Call helper to do the real work for both simulataneous and 1701 * duplicate INIT chunk handling. 1702 */ 1703 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1704 } 1705 1706 1707 /* 1708 * Unexpected INIT-ACK handler. 1709 * 1710 * Section 5.2.3 1711 * If an INIT ACK received by an endpoint in any state other than the 1712 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1713 * An unexpected INIT ACK usually indicates the processing of an old or 1714 * duplicated INIT chunk. 1715 */ 1716 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1717 struct net *net, 1718 const struct sctp_endpoint *ep, 1719 const struct sctp_association *asoc, 1720 const union sctp_subtype type, 1721 void *arg, 1722 struct sctp_cmd_seq *commands) 1723 { 1724 /* Per the above section, we'll discard the chunk if we have an 1725 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1726 */ 1727 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1728 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1729 else 1730 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1731 } 1732 1733 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1734 * 1735 * Section 5.2.4 1736 * A) In this case, the peer may have restarted. 1737 */ 1738 static enum sctp_disposition sctp_sf_do_dupcook_a( 1739 struct net *net, 1740 const struct sctp_endpoint *ep, 1741 const struct sctp_association *asoc, 1742 struct sctp_chunk *chunk, 1743 struct sctp_cmd_seq *commands, 1744 struct sctp_association *new_asoc) 1745 { 1746 struct sctp_init_chunk *peer_init; 1747 enum sctp_disposition disposition; 1748 struct sctp_ulpevent *ev; 1749 struct sctp_chunk *repl; 1750 struct sctp_chunk *err; 1751 1752 /* new_asoc is a brand-new association, so these are not yet 1753 * side effects--it is safe to run them here. 1754 */ 1755 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1756 1757 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1758 GFP_ATOMIC)) 1759 goto nomem; 1760 1761 /* Make sure no new addresses are being added during the 1762 * restart. Though this is a pretty complicated attack 1763 * since you'd have to get inside the cookie. 1764 */ 1765 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1766 return SCTP_DISPOSITION_CONSUME; 1767 } 1768 1769 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1770 * the peer has restarted (Action A), it MUST NOT setup a new 1771 * association but instead resend the SHUTDOWN ACK and send an ERROR 1772 * chunk with a "Cookie Received while Shutting Down" error cause to 1773 * its peer. 1774 */ 1775 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1776 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1777 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1778 chunk, commands); 1779 if (SCTP_DISPOSITION_NOMEM == disposition) 1780 goto nomem; 1781 1782 err = sctp_make_op_error(asoc, chunk, 1783 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1784 NULL, 0, 0); 1785 if (err) 1786 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1787 SCTP_CHUNK(err)); 1788 1789 return SCTP_DISPOSITION_CONSUME; 1790 } 1791 1792 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1793 * data. Consider the optional choice of resending of this data. 1794 */ 1795 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1796 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1797 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1798 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1799 1800 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1801 * and ASCONF-ACK cache. 1802 */ 1803 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1804 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1805 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1806 1807 repl = sctp_make_cookie_ack(new_asoc, chunk); 1808 if (!repl) 1809 goto nomem; 1810 1811 /* Report association restart to upper layer. */ 1812 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1813 new_asoc->c.sinit_num_ostreams, 1814 new_asoc->c.sinit_max_instreams, 1815 NULL, GFP_ATOMIC); 1816 if (!ev) 1817 goto nomem_ev; 1818 1819 /* Update the content of current association. */ 1820 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1821 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1822 if (sctp_state(asoc, SHUTDOWN_PENDING) && 1823 (sctp_sstate(asoc->base.sk, CLOSING) || 1824 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1825 /* if were currently in SHUTDOWN_PENDING, but the socket 1826 * has been closed by user, don't transition to ESTABLISHED. 1827 * Instead trigger SHUTDOWN bundled with COOKIE_ACK. 1828 */ 1829 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1830 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1831 SCTP_ST_CHUNK(0), NULL, 1832 commands); 1833 } else { 1834 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1835 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1836 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1837 } 1838 return SCTP_DISPOSITION_CONSUME; 1839 1840 nomem_ev: 1841 sctp_chunk_free(repl); 1842 nomem: 1843 return SCTP_DISPOSITION_NOMEM; 1844 } 1845 1846 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1847 * 1848 * Section 5.2.4 1849 * B) In this case, both sides may be attempting to start an association 1850 * at about the same time but the peer endpoint started its INIT 1851 * after responding to the local endpoint's INIT 1852 */ 1853 /* This case represents an initialization collision. */ 1854 static enum sctp_disposition sctp_sf_do_dupcook_b( 1855 struct net *net, 1856 const struct sctp_endpoint *ep, 1857 const struct sctp_association *asoc, 1858 struct sctp_chunk *chunk, 1859 struct sctp_cmd_seq *commands, 1860 struct sctp_association *new_asoc) 1861 { 1862 struct sctp_init_chunk *peer_init; 1863 struct sctp_chunk *repl; 1864 1865 /* new_asoc is a brand-new association, so these are not yet 1866 * side effects--it is safe to run them here. 1867 */ 1868 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1869 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1870 GFP_ATOMIC)) 1871 goto nomem; 1872 1873 /* Update the content of current association. */ 1874 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1875 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1876 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1877 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1878 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1879 1880 repl = sctp_make_cookie_ack(new_asoc, chunk); 1881 if (!repl) 1882 goto nomem; 1883 1884 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1885 1886 /* RFC 2960 5.1 Normal Establishment of an Association 1887 * 1888 * D) IMPLEMENTATION NOTE: An implementation may choose to 1889 * send the Communication Up notification to the SCTP user 1890 * upon reception of a valid COOKIE ECHO chunk. 1891 * 1892 * Sadly, this needs to be implemented as a side-effect, because 1893 * we are not guaranteed to have set the association id of the real 1894 * association and so these notifications need to be delayed until 1895 * the association id is allocated. 1896 */ 1897 1898 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1899 1900 /* Sockets API Draft Section 5.3.1.6 1901 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1902 * delivers this notification to inform the application that of the 1903 * peers requested adaptation layer. 1904 * 1905 * This also needs to be done as a side effect for the same reason as 1906 * above. 1907 */ 1908 if (asoc->peer.adaptation_ind) 1909 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1910 1911 return SCTP_DISPOSITION_CONSUME; 1912 1913 nomem: 1914 return SCTP_DISPOSITION_NOMEM; 1915 } 1916 1917 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1918 * 1919 * Section 5.2.4 1920 * C) In this case, the local endpoint's cookie has arrived late. 1921 * Before it arrived, the local endpoint sent an INIT and received an 1922 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1923 * but a new tag of its own. 1924 */ 1925 /* This case represents an initialization collision. */ 1926 static enum sctp_disposition sctp_sf_do_dupcook_c( 1927 struct net *net, 1928 const struct sctp_endpoint *ep, 1929 const struct sctp_association *asoc, 1930 struct sctp_chunk *chunk, 1931 struct sctp_cmd_seq *commands, 1932 struct sctp_association *new_asoc) 1933 { 1934 /* The cookie should be silently discarded. 1935 * The endpoint SHOULD NOT change states and should leave 1936 * any timers running. 1937 */ 1938 return SCTP_DISPOSITION_DISCARD; 1939 } 1940 1941 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1942 * 1943 * Section 5.2.4 1944 * 1945 * D) When both local and remote tags match the endpoint should always 1946 * enter the ESTABLISHED state, if it has not already done so. 1947 */ 1948 /* This case represents an initialization collision. */ 1949 static enum sctp_disposition sctp_sf_do_dupcook_d( 1950 struct net *net, 1951 const struct sctp_endpoint *ep, 1952 const struct sctp_association *asoc, 1953 struct sctp_chunk *chunk, 1954 struct sctp_cmd_seq *commands, 1955 struct sctp_association *new_asoc) 1956 { 1957 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1958 struct sctp_chunk *repl; 1959 1960 /* Clarification from Implementor's Guide: 1961 * D) When both local and remote tags match the endpoint should 1962 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1963 * It should stop any cookie timer that may be running and send 1964 * a COOKIE ACK. 1965 */ 1966 1967 /* Don't accidentally move back into established state. */ 1968 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1969 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1970 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1971 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1972 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1973 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1974 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1975 SCTP_NULL()); 1976 1977 /* RFC 2960 5.1 Normal Establishment of an Association 1978 * 1979 * D) IMPLEMENTATION NOTE: An implementation may choose 1980 * to send the Communication Up notification to the 1981 * SCTP user upon reception of a valid COOKIE 1982 * ECHO chunk. 1983 */ 1984 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1985 SCTP_COMM_UP, 0, 1986 asoc->c.sinit_num_ostreams, 1987 asoc->c.sinit_max_instreams, 1988 NULL, GFP_ATOMIC); 1989 if (!ev) 1990 goto nomem; 1991 1992 /* Sockets API Draft Section 5.3.1.6 1993 * When a peer sends a Adaptation Layer Indication parameter, 1994 * SCTP delivers this notification to inform the application 1995 * that of the peers requested adaptation layer. 1996 */ 1997 if (asoc->peer.adaptation_ind) { 1998 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1999 GFP_ATOMIC); 2000 if (!ai_ev) 2001 goto nomem; 2002 2003 } 2004 } 2005 2006 repl = sctp_make_cookie_ack(new_asoc, chunk); 2007 if (!repl) 2008 goto nomem; 2009 2010 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2011 2012 if (ev) 2013 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2014 SCTP_ULPEVENT(ev)); 2015 if (ai_ev) 2016 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2017 SCTP_ULPEVENT(ai_ev)); 2018 2019 return SCTP_DISPOSITION_CONSUME; 2020 2021 nomem: 2022 if (ai_ev) 2023 sctp_ulpevent_free(ai_ev); 2024 if (ev) 2025 sctp_ulpevent_free(ev); 2026 return SCTP_DISPOSITION_NOMEM; 2027 } 2028 2029 /* 2030 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2031 * chunk was retransmitted and then delayed in the network. 2032 * 2033 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2034 * 2035 * Verification Tag: None. Do cookie validation. 2036 * 2037 * Inputs 2038 * (endpoint, asoc, chunk) 2039 * 2040 * Outputs 2041 * (asoc, reply_msg, msg_up, timers, counters) 2042 * 2043 * The return value is the disposition of the chunk. 2044 */ 2045 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2046 struct net *net, 2047 const struct sctp_endpoint *ep, 2048 const struct sctp_association *asoc, 2049 const union sctp_subtype type, 2050 void *arg, 2051 struct sctp_cmd_seq *commands) 2052 { 2053 struct sctp_association *new_asoc; 2054 struct sctp_chunk *chunk = arg; 2055 enum sctp_disposition retval; 2056 struct sctp_chunk *err_chk_p; 2057 int error = 0; 2058 char action; 2059 2060 /* Make sure that the chunk has a valid length from the protocol 2061 * perspective. In this case check to make sure we have at least 2062 * enough for the chunk header. Cookie length verification is 2063 * done later. 2064 */ 2065 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2066 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2067 commands); 2068 2069 /* "Decode" the chunk. We have no optional parameters so we 2070 * are in good shape. 2071 */ 2072 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2073 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2074 sizeof(struct sctp_chunkhdr))) 2075 goto nomem; 2076 2077 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2078 * of a duplicate COOKIE ECHO match the Verification Tags of the 2079 * current association, consider the State Cookie valid even if 2080 * the lifespan is exceeded. 2081 */ 2082 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2083 &err_chk_p); 2084 2085 /* FIXME: 2086 * If the re-build failed, what is the proper error path 2087 * from here? 2088 * 2089 * [We should abort the association. --piggy] 2090 */ 2091 if (!new_asoc) { 2092 /* FIXME: Several errors are possible. A bad cookie should 2093 * be silently discarded, but think about logging it too. 2094 */ 2095 switch (error) { 2096 case -SCTP_IERROR_NOMEM: 2097 goto nomem; 2098 2099 case -SCTP_IERROR_STALE_COOKIE: 2100 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2101 err_chk_p); 2102 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2103 case -SCTP_IERROR_BAD_SIG: 2104 default: 2105 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2106 } 2107 } 2108 2109 /* Set temp so that it won't be added into hashtable */ 2110 new_asoc->temp = 1; 2111 2112 /* Compare the tie_tag in cookie with the verification tag of 2113 * current association. 2114 */ 2115 action = sctp_tietags_compare(new_asoc, asoc); 2116 2117 switch (action) { 2118 case 'A': /* Association restart. */ 2119 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2120 new_asoc); 2121 break; 2122 2123 case 'B': /* Collision case B. */ 2124 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2125 new_asoc); 2126 break; 2127 2128 case 'C': /* Collision case C. */ 2129 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2130 new_asoc); 2131 break; 2132 2133 case 'D': /* Collision case D. */ 2134 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2135 new_asoc); 2136 break; 2137 2138 default: /* Discard packet for all others. */ 2139 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2140 break; 2141 } 2142 2143 /* Delete the tempory new association. */ 2144 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2145 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2146 2147 /* Restore association pointer to provide SCTP command interpeter 2148 * with a valid context in case it needs to manipulate 2149 * the queues */ 2150 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2151 SCTP_ASOC((struct sctp_association *)asoc)); 2152 2153 return retval; 2154 2155 nomem: 2156 return SCTP_DISPOSITION_NOMEM; 2157 } 2158 2159 /* 2160 * Process an ABORT. (SHUTDOWN-PENDING state) 2161 * 2162 * See sctp_sf_do_9_1_abort(). 2163 */ 2164 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2165 struct net *net, 2166 const struct sctp_endpoint *ep, 2167 const struct sctp_association *asoc, 2168 const union sctp_subtype type, 2169 void *arg, 2170 struct sctp_cmd_seq *commands) 2171 { 2172 struct sctp_chunk *chunk = arg; 2173 2174 if (!sctp_vtag_verify_either(chunk, asoc)) 2175 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2176 2177 /* Make sure that the ABORT chunk has a valid length. 2178 * Since this is an ABORT chunk, we have to discard it 2179 * because of the following text: 2180 * RFC 2960, Section 3.3.7 2181 * If an endpoint receives an ABORT with a format error or for an 2182 * association that doesn't exist, it MUST silently discard it. 2183 * Because the length is "invalid", we can't really discard just 2184 * as we do not know its true length. So, to be safe, discard the 2185 * packet. 2186 */ 2187 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2188 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2189 2190 /* ADD-IP: Special case for ABORT chunks 2191 * F4) One special consideration is that ABORT Chunks arriving 2192 * destined to the IP address being deleted MUST be 2193 * ignored (see Section 5.3.1 for further details). 2194 */ 2195 if (SCTP_ADDR_DEL == 2196 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2197 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2198 2199 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2200 } 2201 2202 /* 2203 * Process an ABORT. (SHUTDOWN-SENT state) 2204 * 2205 * See sctp_sf_do_9_1_abort(). 2206 */ 2207 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2208 struct net *net, 2209 const struct sctp_endpoint *ep, 2210 const struct sctp_association *asoc, 2211 const union sctp_subtype type, 2212 void *arg, 2213 struct sctp_cmd_seq *commands) 2214 { 2215 struct sctp_chunk *chunk = arg; 2216 2217 if (!sctp_vtag_verify_either(chunk, asoc)) 2218 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2219 2220 /* Make sure that the ABORT chunk has a valid length. 2221 * Since this is an ABORT chunk, we have to discard it 2222 * because of the following text: 2223 * RFC 2960, Section 3.3.7 2224 * If an endpoint receives an ABORT with a format error or for an 2225 * association that doesn't exist, it MUST silently discard it. 2226 * Because the length is "invalid", we can't really discard just 2227 * as we do not know its true length. So, to be safe, discard the 2228 * packet. 2229 */ 2230 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2231 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2232 2233 /* ADD-IP: Special case for ABORT chunks 2234 * F4) One special consideration is that ABORT Chunks arriving 2235 * destined to the IP address being deleted MUST be 2236 * ignored (see Section 5.3.1 for further details). 2237 */ 2238 if (SCTP_ADDR_DEL == 2239 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2240 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2241 2242 /* Stop the T2-shutdown timer. */ 2243 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2244 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2245 2246 /* Stop the T5-shutdown guard timer. */ 2247 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2248 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2249 2250 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2251 } 2252 2253 /* 2254 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2255 * 2256 * See sctp_sf_do_9_1_abort(). 2257 */ 2258 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2259 struct net *net, 2260 const struct sctp_endpoint *ep, 2261 const struct sctp_association *asoc, 2262 const union sctp_subtype type, 2263 void *arg, 2264 struct sctp_cmd_seq *commands) 2265 { 2266 /* The same T2 timer, so we should be able to use 2267 * common function with the SHUTDOWN-SENT state. 2268 */ 2269 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2270 } 2271 2272 /* 2273 * Handle an Error received in COOKIE_ECHOED state. 2274 * 2275 * Only handle the error type of stale COOKIE Error, the other errors will 2276 * be ignored. 2277 * 2278 * Inputs 2279 * (endpoint, asoc, chunk) 2280 * 2281 * Outputs 2282 * (asoc, reply_msg, msg_up, timers, counters) 2283 * 2284 * The return value is the disposition of the chunk. 2285 */ 2286 enum sctp_disposition sctp_sf_cookie_echoed_err( 2287 struct net *net, 2288 const struct sctp_endpoint *ep, 2289 const struct sctp_association *asoc, 2290 const union sctp_subtype type, 2291 void *arg, 2292 struct sctp_cmd_seq *commands) 2293 { 2294 struct sctp_chunk *chunk = arg; 2295 struct sctp_errhdr *err; 2296 2297 if (!sctp_vtag_verify(chunk, asoc)) 2298 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2299 2300 /* Make sure that the ERROR chunk has a valid length. 2301 * The parameter walking depends on this as well. 2302 */ 2303 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2304 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2305 commands); 2306 2307 /* Process the error here */ 2308 /* FUTURE FIXME: When PR-SCTP related and other optional 2309 * parms are emitted, this will have to change to handle multiple 2310 * errors. 2311 */ 2312 sctp_walk_errors(err, chunk->chunk_hdr) { 2313 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2314 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2315 arg, commands); 2316 } 2317 2318 /* It is possible to have malformed error causes, and that 2319 * will cause us to end the walk early. However, since 2320 * we are discarding the packet, there should be no adverse 2321 * affects. 2322 */ 2323 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2324 } 2325 2326 /* 2327 * Handle a Stale COOKIE Error 2328 * 2329 * Section: 5.2.6 Handle Stale COOKIE Error 2330 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2331 * one of the following three alternatives. 2332 * ... 2333 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2334 * Preservative parameter requesting an extension to the lifetime of 2335 * the State Cookie. When calculating the time extension, an 2336 * implementation SHOULD use the RTT information measured based on the 2337 * previous COOKIE ECHO / ERROR exchange, and should add no more 2338 * than 1 second beyond the measured RTT, due to long State Cookie 2339 * lifetimes making the endpoint more subject to a replay attack. 2340 * 2341 * Verification Tag: Not explicit, but safe to ignore. 2342 * 2343 * Inputs 2344 * (endpoint, asoc, chunk) 2345 * 2346 * Outputs 2347 * (asoc, reply_msg, msg_up, timers, counters) 2348 * 2349 * The return value is the disposition of the chunk. 2350 */ 2351 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2352 struct net *net, 2353 const struct sctp_endpoint *ep, 2354 const struct sctp_association *asoc, 2355 const union sctp_subtype type, 2356 void *arg, 2357 struct sctp_cmd_seq *commands) 2358 { 2359 int attempts = asoc->init_err_counter + 1; 2360 struct sctp_chunk *chunk = arg, *reply; 2361 struct sctp_cookie_preserve_param bht; 2362 struct sctp_bind_addr *bp; 2363 struct sctp_errhdr *err; 2364 u32 stale; 2365 2366 if (attempts > asoc->max_init_attempts) { 2367 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2368 SCTP_ERROR(ETIMEDOUT)); 2369 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2370 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2371 return SCTP_DISPOSITION_DELETE_TCB; 2372 } 2373 2374 err = (struct sctp_errhdr *)(chunk->skb->data); 2375 2376 /* When calculating the time extension, an implementation 2377 * SHOULD use the RTT information measured based on the 2378 * previous COOKIE ECHO / ERROR exchange, and should add no 2379 * more than 1 second beyond the measured RTT, due to long 2380 * State Cookie lifetimes making the endpoint more subject to 2381 * a replay attack. 2382 * Measure of Staleness's unit is usec. (1/1000000 sec) 2383 * Suggested Cookie Life-span Increment's unit is msec. 2384 * (1/1000 sec) 2385 * In general, if you use the suggested cookie life, the value 2386 * found in the field of measure of staleness should be doubled 2387 * to give ample time to retransmit the new cookie and thus 2388 * yield a higher probability of success on the reattempt. 2389 */ 2390 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2391 stale = (stale * 2) / 1000; 2392 2393 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2394 bht.param_hdr.length = htons(sizeof(bht)); 2395 bht.lifespan_increment = htonl(stale); 2396 2397 /* Build that new INIT chunk. */ 2398 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2399 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2400 if (!reply) 2401 goto nomem; 2402 2403 sctp_addto_chunk(reply, sizeof(bht), &bht); 2404 2405 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2406 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2407 2408 /* Stop pending T3-rtx and heartbeat timers */ 2409 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2410 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2411 2412 /* Delete non-primary peer ip addresses since we are transitioning 2413 * back to the COOKIE-WAIT state 2414 */ 2415 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2416 2417 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2418 * resend 2419 */ 2420 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2421 SCTP_TRANSPORT(asoc->peer.primary_path)); 2422 2423 /* Cast away the const modifier, as we want to just 2424 * rerun it through as a sideffect. 2425 */ 2426 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2427 2428 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2429 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2430 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2431 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2432 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2433 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2434 2435 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2436 2437 return SCTP_DISPOSITION_CONSUME; 2438 2439 nomem: 2440 return SCTP_DISPOSITION_NOMEM; 2441 } 2442 2443 /* 2444 * Process an ABORT. 2445 * 2446 * Section: 9.1 2447 * After checking the Verification Tag, the receiving endpoint shall 2448 * remove the association from its record, and shall report the 2449 * termination to its upper layer. 2450 * 2451 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2452 * B) Rules for packet carrying ABORT: 2453 * 2454 * - The endpoint shall always fill in the Verification Tag field of the 2455 * outbound packet with the destination endpoint's tag value if it 2456 * is known. 2457 * 2458 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2459 * MUST follow the procedure described in Section 8.4. 2460 * 2461 * - The receiver MUST accept the packet if the Verification Tag 2462 * matches either its own tag, OR the tag of its peer. Otherwise, the 2463 * receiver MUST silently discard the packet and take no further 2464 * action. 2465 * 2466 * Inputs 2467 * (endpoint, asoc, chunk) 2468 * 2469 * Outputs 2470 * (asoc, reply_msg, msg_up, timers, counters) 2471 * 2472 * The return value is the disposition of the chunk. 2473 */ 2474 enum sctp_disposition sctp_sf_do_9_1_abort( 2475 struct net *net, 2476 const struct sctp_endpoint *ep, 2477 const struct sctp_association *asoc, 2478 const union sctp_subtype type, 2479 void *arg, 2480 struct sctp_cmd_seq *commands) 2481 { 2482 struct sctp_chunk *chunk = arg; 2483 2484 if (!sctp_vtag_verify_either(chunk, asoc)) 2485 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2486 2487 /* Make sure that the ABORT chunk has a valid length. 2488 * Since this is an ABORT chunk, we have to discard it 2489 * because of the following text: 2490 * RFC 2960, Section 3.3.7 2491 * If an endpoint receives an ABORT with a format error or for an 2492 * association that doesn't exist, it MUST silently discard it. 2493 * Because the length is "invalid", we can't really discard just 2494 * as we do not know its true length. So, to be safe, discard the 2495 * packet. 2496 */ 2497 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2498 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2499 2500 /* ADD-IP: Special case for ABORT chunks 2501 * F4) One special consideration is that ABORT Chunks arriving 2502 * destined to the IP address being deleted MUST be 2503 * ignored (see Section 5.3.1 for further details). 2504 */ 2505 if (SCTP_ADDR_DEL == 2506 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2507 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2508 2509 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2510 } 2511 2512 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2513 struct net *net, 2514 const struct sctp_endpoint *ep, 2515 const struct sctp_association *asoc, 2516 const union sctp_subtype type, 2517 void *arg, 2518 struct sctp_cmd_seq *commands) 2519 { 2520 __be16 error = SCTP_ERROR_NO_ERROR; 2521 struct sctp_chunk *chunk = arg; 2522 unsigned int len; 2523 2524 /* See if we have an error cause code in the chunk. */ 2525 len = ntohs(chunk->chunk_hdr->length); 2526 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2527 struct sctp_errhdr *err; 2528 2529 sctp_walk_errors(err, chunk->chunk_hdr); 2530 if ((void *)err != (void *)chunk->chunk_end) 2531 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 2532 commands); 2533 2534 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2535 } 2536 2537 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2538 /* ASSOC_FAILED will DELETE_TCB. */ 2539 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2540 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2541 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2542 2543 return SCTP_DISPOSITION_ABORT; 2544 } 2545 2546 /* 2547 * Process an ABORT. (COOKIE-WAIT state) 2548 * 2549 * See sctp_sf_do_9_1_abort() above. 2550 */ 2551 enum sctp_disposition sctp_sf_cookie_wait_abort( 2552 struct net *net, 2553 const struct sctp_endpoint *ep, 2554 const struct sctp_association *asoc, 2555 const union sctp_subtype type, 2556 void *arg, 2557 struct sctp_cmd_seq *commands) 2558 { 2559 __be16 error = SCTP_ERROR_NO_ERROR; 2560 struct sctp_chunk *chunk = arg; 2561 unsigned int len; 2562 2563 if (!sctp_vtag_verify_either(chunk, asoc)) 2564 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2565 2566 /* Make sure that the ABORT chunk has a valid length. 2567 * Since this is an ABORT chunk, we have to discard it 2568 * because of the following text: 2569 * RFC 2960, Section 3.3.7 2570 * If an endpoint receives an ABORT with a format error or for an 2571 * association that doesn't exist, it MUST silently discard it. 2572 * Because the length is "invalid", we can't really discard just 2573 * as we do not know its true length. So, to be safe, discard the 2574 * packet. 2575 */ 2576 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2577 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2578 2579 /* See if we have an error cause code in the chunk. */ 2580 len = ntohs(chunk->chunk_hdr->length); 2581 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2582 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2583 2584 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2585 chunk->transport); 2586 } 2587 2588 /* 2589 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2590 */ 2591 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2592 struct net *net, 2593 const struct sctp_endpoint *ep, 2594 const struct sctp_association *asoc, 2595 const union sctp_subtype type, 2596 void *arg, 2597 struct sctp_cmd_seq *commands) 2598 { 2599 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2600 ENOPROTOOPT, asoc, 2601 (struct sctp_transport *)arg); 2602 } 2603 2604 /* 2605 * Process an ABORT. (COOKIE-ECHOED state) 2606 */ 2607 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2608 struct net *net, 2609 const struct sctp_endpoint *ep, 2610 const struct sctp_association *asoc, 2611 const union sctp_subtype type, 2612 void *arg, 2613 struct sctp_cmd_seq *commands) 2614 { 2615 /* There is a single T1 timer, so we should be able to use 2616 * common function with the COOKIE-WAIT state. 2617 */ 2618 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2619 } 2620 2621 /* 2622 * Stop T1 timer and abort association with "INIT failed". 2623 * 2624 * This is common code called by several sctp_sf_*_abort() functions above. 2625 */ 2626 static enum sctp_disposition sctp_stop_t1_and_abort( 2627 struct net *net, 2628 struct sctp_cmd_seq *commands, 2629 __be16 error, int sk_err, 2630 const struct sctp_association *asoc, 2631 struct sctp_transport *transport) 2632 { 2633 pr_debug("%s: ABORT received (INIT)\n", __func__); 2634 2635 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2636 SCTP_STATE(SCTP_STATE_CLOSED)); 2637 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2638 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2639 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2640 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2641 /* CMD_INIT_FAILED will DELETE_TCB. */ 2642 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2643 SCTP_PERR(error)); 2644 2645 return SCTP_DISPOSITION_ABORT; 2646 } 2647 2648 /* 2649 * sctp_sf_do_9_2_shut 2650 * 2651 * Section: 9.2 2652 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2653 * - enter the SHUTDOWN-RECEIVED state, 2654 * 2655 * - stop accepting new data from its SCTP user 2656 * 2657 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2658 * that all its outstanding DATA chunks have been received by the 2659 * SHUTDOWN sender. 2660 * 2661 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2662 * send a SHUTDOWN in response to a ULP request. And should discard 2663 * subsequent SHUTDOWN chunks. 2664 * 2665 * If there are still outstanding DATA chunks left, the SHUTDOWN 2666 * receiver shall continue to follow normal data transmission 2667 * procedures defined in Section 6 until all outstanding DATA chunks 2668 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2669 * new data from its SCTP user. 2670 * 2671 * Verification Tag: 8.5 Verification Tag [Normal verification] 2672 * 2673 * Inputs 2674 * (endpoint, asoc, chunk) 2675 * 2676 * Outputs 2677 * (asoc, reply_msg, msg_up, timers, counters) 2678 * 2679 * The return value is the disposition of the chunk. 2680 */ 2681 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2682 struct net *net, 2683 const struct sctp_endpoint *ep, 2684 const struct sctp_association *asoc, 2685 const union sctp_subtype type, 2686 void *arg, 2687 struct sctp_cmd_seq *commands) 2688 { 2689 enum sctp_disposition disposition; 2690 struct sctp_chunk *chunk = arg; 2691 struct sctp_shutdownhdr *sdh; 2692 struct sctp_ulpevent *ev; 2693 __u32 ctsn; 2694 2695 if (!sctp_vtag_verify(chunk, asoc)) 2696 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2697 2698 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2699 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2700 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2701 commands); 2702 2703 /* Convert the elaborate header. */ 2704 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2705 skb_pull(chunk->skb, sizeof(*sdh)); 2706 chunk->subh.shutdown_hdr = sdh; 2707 ctsn = ntohl(sdh->cum_tsn_ack); 2708 2709 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2710 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2711 asoc->ctsn_ack_point); 2712 2713 return SCTP_DISPOSITION_DISCARD; 2714 } 2715 2716 /* If Cumulative TSN Ack beyond the max tsn currently 2717 * send, terminating the association and respond to the 2718 * sender with an ABORT. 2719 */ 2720 if (!TSN_lt(ctsn, asoc->next_tsn)) 2721 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2722 2723 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2724 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2725 * inform the application that it should cease sending data. 2726 */ 2727 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2728 if (!ev) { 2729 disposition = SCTP_DISPOSITION_NOMEM; 2730 goto out; 2731 } 2732 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2733 2734 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2735 * - enter the SHUTDOWN-RECEIVED state, 2736 * - stop accepting new data from its SCTP user 2737 * 2738 * [This is implicit in the new state.] 2739 */ 2740 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2741 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2742 disposition = SCTP_DISPOSITION_CONSUME; 2743 2744 if (sctp_outq_is_empty(&asoc->outqueue)) { 2745 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2746 arg, commands); 2747 } 2748 2749 if (SCTP_DISPOSITION_NOMEM == disposition) 2750 goto out; 2751 2752 /* - verify, by checking the Cumulative TSN Ack field of the 2753 * chunk, that all its outstanding DATA chunks have been 2754 * received by the SHUTDOWN sender. 2755 */ 2756 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2757 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2758 2759 out: 2760 return disposition; 2761 } 2762 2763 /* 2764 * sctp_sf_do_9_2_shut_ctsn 2765 * 2766 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2767 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2768 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2769 * MUST be processed. 2770 */ 2771 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2772 struct net *net, 2773 const struct sctp_endpoint *ep, 2774 const struct sctp_association *asoc, 2775 const union sctp_subtype type, 2776 void *arg, 2777 struct sctp_cmd_seq *commands) 2778 { 2779 struct sctp_chunk *chunk = arg; 2780 struct sctp_shutdownhdr *sdh; 2781 __u32 ctsn; 2782 2783 if (!sctp_vtag_verify(chunk, asoc)) 2784 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2785 2786 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2787 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2788 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2789 commands); 2790 2791 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2792 ctsn = ntohl(sdh->cum_tsn_ack); 2793 2794 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2795 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2796 asoc->ctsn_ack_point); 2797 2798 return SCTP_DISPOSITION_DISCARD; 2799 } 2800 2801 /* If Cumulative TSN Ack beyond the max tsn currently 2802 * send, terminating the association and respond to the 2803 * sender with an ABORT. 2804 */ 2805 if (!TSN_lt(ctsn, asoc->next_tsn)) 2806 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2807 2808 /* verify, by checking the Cumulative TSN Ack field of the 2809 * chunk, that all its outstanding DATA chunks have been 2810 * received by the SHUTDOWN sender. 2811 */ 2812 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2813 SCTP_BE32(sdh->cum_tsn_ack)); 2814 2815 return SCTP_DISPOSITION_CONSUME; 2816 } 2817 2818 /* RFC 2960 9.2 2819 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2820 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2821 * transport addresses (either in the IP addresses or in the INIT chunk) 2822 * that belong to this association, it should discard the INIT chunk and 2823 * retransmit the SHUTDOWN ACK chunk. 2824 */ 2825 enum sctp_disposition sctp_sf_do_9_2_reshutack( 2826 struct net *net, 2827 const struct sctp_endpoint *ep, 2828 const struct sctp_association *asoc, 2829 const union sctp_subtype type, 2830 void *arg, 2831 struct sctp_cmd_seq *commands) 2832 { 2833 struct sctp_chunk *chunk = arg; 2834 struct sctp_chunk *reply; 2835 2836 /* Make sure that the chunk has a valid length */ 2837 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2838 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2839 commands); 2840 2841 /* Since we are not going to really process this INIT, there 2842 * is no point in verifying chunk boundries. Just generate 2843 * the SHUTDOWN ACK. 2844 */ 2845 reply = sctp_make_shutdown_ack(asoc, chunk); 2846 if (NULL == reply) 2847 goto nomem; 2848 2849 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2850 * the T2-SHUTDOWN timer. 2851 */ 2852 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2853 2854 /* and restart the T2-shutdown timer. */ 2855 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2856 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2857 2858 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2859 2860 return SCTP_DISPOSITION_CONSUME; 2861 nomem: 2862 return SCTP_DISPOSITION_NOMEM; 2863 } 2864 2865 /* 2866 * sctp_sf_do_ecn_cwr 2867 * 2868 * Section: Appendix A: Explicit Congestion Notification 2869 * 2870 * CWR: 2871 * 2872 * RFC 2481 details a specific bit for a sender to send in the header of 2873 * its next outbound TCP segment to indicate to its peer that it has 2874 * reduced its congestion window. This is termed the CWR bit. For 2875 * SCTP the same indication is made by including the CWR chunk. 2876 * This chunk contains one data element, i.e. the TSN number that 2877 * was sent in the ECNE chunk. This element represents the lowest 2878 * TSN number in the datagram that was originally marked with the 2879 * CE bit. 2880 * 2881 * Verification Tag: 8.5 Verification Tag [Normal verification] 2882 * Inputs 2883 * (endpoint, asoc, chunk) 2884 * 2885 * Outputs 2886 * (asoc, reply_msg, msg_up, timers, counters) 2887 * 2888 * The return value is the disposition of the chunk. 2889 */ 2890 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 2891 const struct sctp_endpoint *ep, 2892 const struct sctp_association *asoc, 2893 const union sctp_subtype type, 2894 void *arg, 2895 struct sctp_cmd_seq *commands) 2896 { 2897 struct sctp_chunk *chunk = arg; 2898 struct sctp_cwrhdr *cwr; 2899 u32 lowest_tsn; 2900 2901 if (!sctp_vtag_verify(chunk, asoc)) 2902 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2903 2904 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 2905 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2906 commands); 2907 2908 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 2909 skb_pull(chunk->skb, sizeof(*cwr)); 2910 2911 lowest_tsn = ntohl(cwr->lowest_tsn); 2912 2913 /* Does this CWR ack the last sent congestion notification? */ 2914 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2915 /* Stop sending ECNE. */ 2916 sctp_add_cmd_sf(commands, 2917 SCTP_CMD_ECN_CWR, 2918 SCTP_U32(lowest_tsn)); 2919 } 2920 return SCTP_DISPOSITION_CONSUME; 2921 } 2922 2923 /* 2924 * sctp_sf_do_ecne 2925 * 2926 * Section: Appendix A: Explicit Congestion Notification 2927 * 2928 * ECN-Echo 2929 * 2930 * RFC 2481 details a specific bit for a receiver to send back in its 2931 * TCP acknowledgements to notify the sender of the Congestion 2932 * Experienced (CE) bit having arrived from the network. For SCTP this 2933 * same indication is made by including the ECNE chunk. This chunk 2934 * contains one data element, i.e. the lowest TSN associated with the IP 2935 * datagram marked with the CE bit..... 2936 * 2937 * Verification Tag: 8.5 Verification Tag [Normal verification] 2938 * Inputs 2939 * (endpoint, asoc, chunk) 2940 * 2941 * Outputs 2942 * (asoc, reply_msg, msg_up, timers, counters) 2943 * 2944 * The return value is the disposition of the chunk. 2945 */ 2946 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 2947 const struct sctp_endpoint *ep, 2948 const struct sctp_association *asoc, 2949 const union sctp_subtype type, 2950 void *arg, struct sctp_cmd_seq *commands) 2951 { 2952 struct sctp_chunk *chunk = arg; 2953 struct sctp_ecnehdr *ecne; 2954 2955 if (!sctp_vtag_verify(chunk, asoc)) 2956 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2957 2958 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 2959 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2960 commands); 2961 2962 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 2963 skb_pull(chunk->skb, sizeof(*ecne)); 2964 2965 /* If this is a newer ECNE than the last CWR packet we sent out */ 2966 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2967 SCTP_U32(ntohl(ecne->lowest_tsn))); 2968 2969 return SCTP_DISPOSITION_CONSUME; 2970 } 2971 2972 /* 2973 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2974 * 2975 * The SCTP endpoint MUST always acknowledge the reception of each valid 2976 * DATA chunk. 2977 * 2978 * The guidelines on delayed acknowledgement algorithm specified in 2979 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2980 * acknowledgement SHOULD be generated for at least every second packet 2981 * (not every second DATA chunk) received, and SHOULD be generated within 2982 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2983 * situations it may be beneficial for an SCTP transmitter to be more 2984 * conservative than the algorithms detailed in this document allow. 2985 * However, an SCTP transmitter MUST NOT be more aggressive than the 2986 * following algorithms allow. 2987 * 2988 * A SCTP receiver MUST NOT generate more than one SACK for every 2989 * incoming packet, other than to update the offered window as the 2990 * receiving application consumes new data. 2991 * 2992 * Verification Tag: 8.5 Verification Tag [Normal verification] 2993 * 2994 * Inputs 2995 * (endpoint, asoc, chunk) 2996 * 2997 * Outputs 2998 * (asoc, reply_msg, msg_up, timers, counters) 2999 * 3000 * The return value is the disposition of the chunk. 3001 */ 3002 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3003 const struct sctp_endpoint *ep, 3004 const struct sctp_association *asoc, 3005 const union sctp_subtype type, 3006 void *arg, 3007 struct sctp_cmd_seq *commands) 3008 { 3009 union sctp_arg force = SCTP_NOFORCE(); 3010 struct sctp_chunk *chunk = arg; 3011 int error; 3012 3013 if (!sctp_vtag_verify(chunk, asoc)) { 3014 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3015 SCTP_NULL()); 3016 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3017 } 3018 3019 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3020 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3021 commands); 3022 3023 error = sctp_eat_data(asoc, chunk, commands); 3024 switch (error) { 3025 case SCTP_IERROR_NO_ERROR: 3026 break; 3027 case SCTP_IERROR_HIGH_TSN: 3028 case SCTP_IERROR_BAD_STREAM: 3029 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3030 goto discard_noforce; 3031 case SCTP_IERROR_DUP_TSN: 3032 case SCTP_IERROR_IGNORE_TSN: 3033 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3034 goto discard_force; 3035 case SCTP_IERROR_NO_DATA: 3036 return SCTP_DISPOSITION_ABORT; 3037 case SCTP_IERROR_PROTO_VIOLATION: 3038 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3039 (u8 *)chunk->subh.data_hdr, 3040 sctp_datahdr_len(&asoc->stream)); 3041 default: 3042 BUG(); 3043 } 3044 3045 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3046 force = SCTP_FORCE(); 3047 3048 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3049 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3050 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3051 } 3052 3053 /* If this is the last chunk in a packet, we need to count it 3054 * toward sack generation. Note that we need to SACK every 3055 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3056 * THEM. We elect to NOT generate SACK's if the chunk fails 3057 * the verification tag test. 3058 * 3059 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3060 * 3061 * The SCTP endpoint MUST always acknowledge the reception of 3062 * each valid DATA chunk. 3063 * 3064 * The guidelines on delayed acknowledgement algorithm 3065 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3066 * Specifically, an acknowledgement SHOULD be generated for at 3067 * least every second packet (not every second DATA chunk) 3068 * received, and SHOULD be generated within 200 ms of the 3069 * arrival of any unacknowledged DATA chunk. In some 3070 * situations it may be beneficial for an SCTP transmitter to 3071 * be more conservative than the algorithms detailed in this 3072 * document allow. However, an SCTP transmitter MUST NOT be 3073 * more aggressive than the following algorithms allow. 3074 */ 3075 if (chunk->end_of_packet) 3076 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3077 3078 return SCTP_DISPOSITION_CONSUME; 3079 3080 discard_force: 3081 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3082 * 3083 * When a packet arrives with duplicate DATA chunk(s) and with 3084 * no new DATA chunk(s), the endpoint MUST immediately send a 3085 * SACK with no delay. If a packet arrives with duplicate 3086 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3087 * MAY immediately send a SACK. Normally receipt of duplicate 3088 * DATA chunks will occur when the original SACK chunk was lost 3089 * and the peer's RTO has expired. The duplicate TSN number(s) 3090 * SHOULD be reported in the SACK as duplicate. 3091 */ 3092 /* In our case, we split the MAY SACK advice up whether or not 3093 * the last chunk is a duplicate.' 3094 */ 3095 if (chunk->end_of_packet) 3096 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3097 return SCTP_DISPOSITION_DISCARD; 3098 3099 discard_noforce: 3100 if (chunk->end_of_packet) 3101 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3102 3103 return SCTP_DISPOSITION_DISCARD; 3104 } 3105 3106 /* 3107 * sctp_sf_eat_data_fast_4_4 3108 * 3109 * Section: 4 (4) 3110 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3111 * DATA chunks without delay. 3112 * 3113 * Verification Tag: 8.5 Verification Tag [Normal verification] 3114 * Inputs 3115 * (endpoint, asoc, chunk) 3116 * 3117 * Outputs 3118 * (asoc, reply_msg, msg_up, timers, counters) 3119 * 3120 * The return value is the disposition of the chunk. 3121 */ 3122 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3123 struct net *net, 3124 const struct sctp_endpoint *ep, 3125 const struct sctp_association *asoc, 3126 const union sctp_subtype type, 3127 void *arg, 3128 struct sctp_cmd_seq *commands) 3129 { 3130 struct sctp_chunk *chunk = arg; 3131 int error; 3132 3133 if (!sctp_vtag_verify(chunk, asoc)) { 3134 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3135 SCTP_NULL()); 3136 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3137 } 3138 3139 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3140 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3141 commands); 3142 3143 error = sctp_eat_data(asoc, chunk, commands); 3144 switch (error) { 3145 case SCTP_IERROR_NO_ERROR: 3146 case SCTP_IERROR_HIGH_TSN: 3147 case SCTP_IERROR_DUP_TSN: 3148 case SCTP_IERROR_IGNORE_TSN: 3149 case SCTP_IERROR_BAD_STREAM: 3150 break; 3151 case SCTP_IERROR_NO_DATA: 3152 return SCTP_DISPOSITION_ABORT; 3153 case SCTP_IERROR_PROTO_VIOLATION: 3154 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3155 (u8 *)chunk->subh.data_hdr, 3156 sctp_datahdr_len(&asoc->stream)); 3157 default: 3158 BUG(); 3159 } 3160 3161 /* Go a head and force a SACK, since we are shutting down. */ 3162 3163 /* Implementor's Guide. 3164 * 3165 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3166 * respond to each received packet containing one or more DATA chunk(s) 3167 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3168 */ 3169 if (chunk->end_of_packet) { 3170 /* We must delay the chunk creation since the cumulative 3171 * TSN has not been updated yet. 3172 */ 3173 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3174 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3175 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3176 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3177 } 3178 3179 return SCTP_DISPOSITION_CONSUME; 3180 } 3181 3182 /* 3183 * Section: 6.2 Processing a Received SACK 3184 * D) Any time a SACK arrives, the endpoint performs the following: 3185 * 3186 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3187 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3188 * increasing, a SACK whose Cumulative TSN Ack is less than the 3189 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3190 * 3191 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3192 * of bytes still outstanding after processing the Cumulative TSN Ack 3193 * and the Gap Ack Blocks. 3194 * 3195 * iii) If the SACK is missing a TSN that was previously 3196 * acknowledged via a Gap Ack Block (e.g., the data receiver 3197 * reneged on the data), then mark the corresponding DATA chunk 3198 * as available for retransmit: Mark it as missing for fast 3199 * retransmit as described in Section 7.2.4 and if no retransmit 3200 * timer is running for the destination address to which the DATA 3201 * chunk was originally transmitted, then T3-rtx is started for 3202 * that destination address. 3203 * 3204 * Verification Tag: 8.5 Verification Tag [Normal verification] 3205 * 3206 * Inputs 3207 * (endpoint, asoc, chunk) 3208 * 3209 * Outputs 3210 * (asoc, reply_msg, msg_up, timers, counters) 3211 * 3212 * The return value is the disposition of the chunk. 3213 */ 3214 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3215 const struct sctp_endpoint *ep, 3216 const struct sctp_association *asoc, 3217 const union sctp_subtype type, 3218 void *arg, 3219 struct sctp_cmd_seq *commands) 3220 { 3221 struct sctp_chunk *chunk = arg; 3222 struct sctp_sackhdr *sackh; 3223 __u32 ctsn; 3224 3225 trace_sctp_probe(ep, asoc, chunk); 3226 3227 if (!sctp_vtag_verify(chunk, asoc)) 3228 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3229 3230 /* Make sure that the SACK chunk has a valid length. */ 3231 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3232 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3233 commands); 3234 3235 /* Pull the SACK chunk from the data buffer */ 3236 sackh = sctp_sm_pull_sack(chunk); 3237 /* Was this a bogus SACK? */ 3238 if (!sackh) 3239 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3240 chunk->subh.sack_hdr = sackh; 3241 ctsn = ntohl(sackh->cum_tsn_ack); 3242 3243 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3244 * Ack Point, then drop the SACK. Since Cumulative TSN 3245 * Ack is monotonically increasing, a SACK whose 3246 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3247 * Point indicates an out-of-order SACK. 3248 */ 3249 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3250 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3251 asoc->ctsn_ack_point); 3252 3253 return SCTP_DISPOSITION_DISCARD; 3254 } 3255 3256 /* If Cumulative TSN Ack beyond the max tsn currently 3257 * send, terminating the association and respond to the 3258 * sender with an ABORT. 3259 */ 3260 if (!TSN_lt(ctsn, asoc->next_tsn)) 3261 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3262 3263 /* Return this SACK for further processing. */ 3264 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3265 3266 /* Note: We do the rest of the work on the PROCESS_SACK 3267 * sideeffect. 3268 */ 3269 return SCTP_DISPOSITION_CONSUME; 3270 } 3271 3272 /* 3273 * Generate an ABORT in response to a packet. 3274 * 3275 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3276 * 3277 * 8) The receiver should respond to the sender of the OOTB packet with 3278 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3279 * MUST fill in the Verification Tag field of the outbound packet 3280 * with the value found in the Verification Tag field of the OOTB 3281 * packet and set the T-bit in the Chunk Flags to indicate that the 3282 * Verification Tag is reflected. After sending this ABORT, the 3283 * receiver of the OOTB packet shall discard the OOTB packet and take 3284 * no further action. 3285 * 3286 * Verification Tag: 3287 * 3288 * The return value is the disposition of the chunk. 3289 */ 3290 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3291 struct net *net, 3292 const struct sctp_endpoint *ep, 3293 const struct sctp_association *asoc, 3294 const union sctp_subtype type, 3295 void *arg, 3296 struct sctp_cmd_seq *commands) 3297 { 3298 struct sctp_packet *packet = NULL; 3299 struct sctp_chunk *chunk = arg; 3300 struct sctp_chunk *abort; 3301 3302 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3303 if (!packet) 3304 return SCTP_DISPOSITION_NOMEM; 3305 3306 /* Make an ABORT. The T bit will be set if the asoc 3307 * is NULL. 3308 */ 3309 abort = sctp_make_abort(asoc, chunk, 0); 3310 if (!abort) { 3311 sctp_ootb_pkt_free(packet); 3312 return SCTP_DISPOSITION_NOMEM; 3313 } 3314 3315 /* Reflect vtag if T-Bit is set */ 3316 if (sctp_test_T_bit(abort)) 3317 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3318 3319 /* Set the skb to the belonging sock for accounting. */ 3320 abort->skb->sk = ep->base.sk; 3321 3322 sctp_packet_append_chunk(packet, abort); 3323 3324 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3325 SCTP_PACKET(packet)); 3326 3327 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3328 3329 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3330 return SCTP_DISPOSITION_CONSUME; 3331 } 3332 3333 /* 3334 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3335 * event as ULP notification for each cause included in the chunk. 3336 * 3337 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3338 * 3339 * The return value is the disposition of the chunk. 3340 */ 3341 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3342 const struct sctp_endpoint *ep, 3343 const struct sctp_association *asoc, 3344 const union sctp_subtype type, 3345 void *arg, 3346 struct sctp_cmd_seq *commands) 3347 { 3348 struct sctp_chunk *chunk = arg; 3349 struct sctp_errhdr *err; 3350 3351 if (!sctp_vtag_verify(chunk, asoc)) 3352 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3353 3354 /* Make sure that the ERROR chunk has a valid length. */ 3355 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3356 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3357 commands); 3358 sctp_walk_errors(err, chunk->chunk_hdr); 3359 if ((void *)err != (void *)chunk->chunk_end) 3360 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3361 (void *)err, commands); 3362 3363 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3364 SCTP_CHUNK(chunk)); 3365 3366 return SCTP_DISPOSITION_CONSUME; 3367 } 3368 3369 /* 3370 * Process an inbound SHUTDOWN ACK. 3371 * 3372 * From Section 9.2: 3373 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3374 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3375 * peer, and remove all record of the association. 3376 * 3377 * The return value is the disposition. 3378 */ 3379 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3380 const struct sctp_endpoint *ep, 3381 const struct sctp_association *asoc, 3382 const union sctp_subtype type, 3383 void *arg, 3384 struct sctp_cmd_seq *commands) 3385 { 3386 struct sctp_chunk *chunk = arg; 3387 struct sctp_chunk *reply; 3388 struct sctp_ulpevent *ev; 3389 3390 if (!sctp_vtag_verify(chunk, asoc)) 3391 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3392 3393 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3394 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3395 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3396 commands); 3397 /* 10.2 H) SHUTDOWN COMPLETE notification 3398 * 3399 * When SCTP completes the shutdown procedures (section 9.2) this 3400 * notification is passed to the upper layer. 3401 */ 3402 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3403 0, 0, 0, NULL, GFP_ATOMIC); 3404 if (!ev) 3405 goto nomem; 3406 3407 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3408 reply = sctp_make_shutdown_complete(asoc, chunk); 3409 if (!reply) 3410 goto nomem_chunk; 3411 3412 /* Do all the commands now (after allocation), so that we 3413 * have consistent state if memory allocation failes 3414 */ 3415 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3416 3417 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3418 * stop the T2-shutdown timer, 3419 */ 3420 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3421 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3422 3423 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3424 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3425 3426 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3427 SCTP_STATE(SCTP_STATE_CLOSED)); 3428 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3429 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3430 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3431 3432 /* ...and remove all record of the association. */ 3433 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3434 return SCTP_DISPOSITION_DELETE_TCB; 3435 3436 nomem_chunk: 3437 sctp_ulpevent_free(ev); 3438 nomem: 3439 return SCTP_DISPOSITION_NOMEM; 3440 } 3441 3442 /* 3443 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3444 * 3445 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3446 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3447 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3448 * packet must fill in the Verification Tag field of the outbound 3449 * packet with the Verification Tag received in the SHUTDOWN ACK and 3450 * set the T-bit in the Chunk Flags to indicate that the Verification 3451 * Tag is reflected. 3452 * 3453 * 8) The receiver should respond to the sender of the OOTB packet with 3454 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3455 * MUST fill in the Verification Tag field of the outbound packet 3456 * with the value found in the Verification Tag field of the OOTB 3457 * packet and set the T-bit in the Chunk Flags to indicate that the 3458 * Verification Tag is reflected. After sending this ABORT, the 3459 * receiver of the OOTB packet shall discard the OOTB packet and take 3460 * no further action. 3461 */ 3462 enum sctp_disposition sctp_sf_ootb(struct net *net, 3463 const struct sctp_endpoint *ep, 3464 const struct sctp_association *asoc, 3465 const union sctp_subtype type, 3466 void *arg, struct sctp_cmd_seq *commands) 3467 { 3468 struct sctp_chunk *chunk = arg; 3469 struct sk_buff *skb = chunk->skb; 3470 struct sctp_chunkhdr *ch; 3471 struct sctp_errhdr *err; 3472 int ootb_cookie_ack = 0; 3473 int ootb_shut_ack = 0; 3474 __u8 *ch_end; 3475 3476 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3477 3478 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3479 do { 3480 /* Report violation if the chunk is less then minimal */ 3481 if (ntohs(ch->length) < sizeof(*ch)) 3482 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3483 commands); 3484 3485 /* Report violation if chunk len overflows */ 3486 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3487 if (ch_end > skb_tail_pointer(skb)) 3488 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3489 commands); 3490 3491 /* Now that we know we at least have a chunk header, 3492 * do things that are type appropriate. 3493 */ 3494 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3495 ootb_shut_ack = 1; 3496 3497 /* RFC 2960, Section 3.3.7 3498 * Moreover, under any circumstances, an endpoint that 3499 * receives an ABORT MUST NOT respond to that ABORT by 3500 * sending an ABORT of its own. 3501 */ 3502 if (SCTP_CID_ABORT == ch->type) 3503 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3504 3505 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3506 * or a COOKIE ACK the SCTP Packet should be silently 3507 * discarded. 3508 */ 3509 3510 if (SCTP_CID_COOKIE_ACK == ch->type) 3511 ootb_cookie_ack = 1; 3512 3513 if (SCTP_CID_ERROR == ch->type) { 3514 sctp_walk_errors(err, ch) { 3515 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3516 ootb_cookie_ack = 1; 3517 break; 3518 } 3519 } 3520 } 3521 3522 ch = (struct sctp_chunkhdr *)ch_end; 3523 } while (ch_end < skb_tail_pointer(skb)); 3524 3525 if (ootb_shut_ack) 3526 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3527 else if (ootb_cookie_ack) 3528 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3529 else 3530 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3531 } 3532 3533 /* 3534 * Handle an "Out of the blue" SHUTDOWN ACK. 3535 * 3536 * Section: 8.4 5, sctpimpguide 2.41. 3537 * 3538 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3539 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3540 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3541 * packet must fill in the Verification Tag field of the outbound 3542 * packet with the Verification Tag received in the SHUTDOWN ACK and 3543 * set the T-bit in the Chunk Flags to indicate that the Verification 3544 * Tag is reflected. 3545 * 3546 * Inputs 3547 * (endpoint, asoc, type, arg, commands) 3548 * 3549 * Outputs 3550 * (enum sctp_disposition) 3551 * 3552 * The return value is the disposition of the chunk. 3553 */ 3554 static enum sctp_disposition sctp_sf_shut_8_4_5( 3555 struct net *net, 3556 const struct sctp_endpoint *ep, 3557 const struct sctp_association *asoc, 3558 const union sctp_subtype type, 3559 void *arg, 3560 struct sctp_cmd_seq *commands) 3561 { 3562 struct sctp_packet *packet = NULL; 3563 struct sctp_chunk *chunk = arg; 3564 struct sctp_chunk *shut; 3565 3566 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3567 if (!packet) 3568 return SCTP_DISPOSITION_NOMEM; 3569 3570 /* Make an SHUTDOWN_COMPLETE. 3571 * The T bit will be set if the asoc is NULL. 3572 */ 3573 shut = sctp_make_shutdown_complete(asoc, chunk); 3574 if (!shut) { 3575 sctp_ootb_pkt_free(packet); 3576 return SCTP_DISPOSITION_NOMEM; 3577 } 3578 3579 /* Reflect vtag if T-Bit is set */ 3580 if (sctp_test_T_bit(shut)) 3581 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3582 3583 /* Set the skb to the belonging sock for accounting. */ 3584 shut->skb->sk = ep->base.sk; 3585 3586 sctp_packet_append_chunk(packet, shut); 3587 3588 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3589 SCTP_PACKET(packet)); 3590 3591 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3592 3593 /* If the chunk length is invalid, we don't want to process 3594 * the reset of the packet. 3595 */ 3596 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3597 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3598 3599 /* We need to discard the rest of the packet to prevent 3600 * potential bomming attacks from additional bundled chunks. 3601 * This is documented in SCTP Threats ID. 3602 */ 3603 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3604 } 3605 3606 /* 3607 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3608 * 3609 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3610 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3611 * procedures in section 8.4 SHOULD be followed, in other words it 3612 * should be treated as an Out Of The Blue packet. 3613 * [This means that we do NOT check the Verification Tag on these 3614 * chunks. --piggy ] 3615 * 3616 */ 3617 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3618 const struct sctp_endpoint *ep, 3619 const struct sctp_association *asoc, 3620 const union sctp_subtype type, 3621 void *arg, 3622 struct sctp_cmd_seq *commands) 3623 { 3624 struct sctp_chunk *chunk = arg; 3625 3626 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3627 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3628 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3629 commands); 3630 3631 /* Although we do have an association in this case, it corresponds 3632 * to a restarted association. So the packet is treated as an OOTB 3633 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3634 * called with a NULL association. 3635 */ 3636 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3637 3638 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3639 } 3640 3641 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3642 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3643 const struct sctp_endpoint *ep, 3644 const struct sctp_association *asoc, 3645 const union sctp_subtype type, 3646 void *arg, 3647 struct sctp_cmd_seq *commands) 3648 { 3649 struct sctp_paramhdr *err_param = NULL; 3650 struct sctp_chunk *asconf_ack = NULL; 3651 struct sctp_chunk *chunk = arg; 3652 struct sctp_addiphdr *hdr; 3653 __u32 serial; 3654 3655 if (!sctp_vtag_verify(chunk, asoc)) { 3656 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3657 SCTP_NULL()); 3658 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3659 } 3660 3661 /* ADD-IP: Section 4.1.1 3662 * This chunk MUST be sent in an authenticated way by using 3663 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3664 * is received unauthenticated it MUST be silently discarded as 3665 * described in [I-D.ietf-tsvwg-sctp-auth]. 3666 */ 3667 if (!net->sctp.addip_noauth && !chunk->auth) 3668 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3669 commands); 3670 3671 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3672 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3673 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3674 commands); 3675 3676 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3677 serial = ntohl(hdr->serial); 3678 3679 /* Verify the ASCONF chunk before processing it. */ 3680 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3681 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3682 (void *)err_param, commands); 3683 3684 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3685 * the endpoint stored in a new association variable 3686 * 'Peer-Serial-Number'. 3687 */ 3688 if (serial == asoc->peer.addip_serial + 1) { 3689 /* If this is the first instance of ASCONF in the packet, 3690 * we can clean our old ASCONF-ACKs. 3691 */ 3692 if (!chunk->has_asconf) 3693 sctp_assoc_clean_asconf_ack_cache(asoc); 3694 3695 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3696 * expected, process the ASCONF as described below and after 3697 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3698 * the response packet and cache a copy of it (in the event it 3699 * later needs to be retransmitted). 3700 * 3701 * Essentially, do V1-V5. 3702 */ 3703 asconf_ack = sctp_process_asconf((struct sctp_association *) 3704 asoc, chunk); 3705 if (!asconf_ack) 3706 return SCTP_DISPOSITION_NOMEM; 3707 } else if (serial < asoc->peer.addip_serial + 1) { 3708 /* ADDIP 5.2 E2) 3709 * If the value found in the Sequence Number is less than the 3710 * ('Peer- Sequence-Number' + 1), simply skip to the next 3711 * ASCONF, and include in the outbound response packet 3712 * any previously cached ASCONF-ACK response that was 3713 * sent and saved that matches the Sequence Number of the 3714 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3715 * Chunk exists. This will occur when an older ASCONF 3716 * arrives out of order. In such a case, the receiver 3717 * should skip the ASCONF Chunk and not include ASCONF-ACK 3718 * Chunk for that chunk. 3719 */ 3720 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3721 if (!asconf_ack) 3722 return SCTP_DISPOSITION_DISCARD; 3723 3724 /* Reset the transport so that we select the correct one 3725 * this time around. This is to make sure that we don't 3726 * accidentally use a stale transport that's been removed. 3727 */ 3728 asconf_ack->transport = NULL; 3729 } else { 3730 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3731 * it must be either a stale packet or from an attacker. 3732 */ 3733 return SCTP_DISPOSITION_DISCARD; 3734 } 3735 3736 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3737 * containing the ASCONF-ACK Chunks MUST be the source address of 3738 * the SCTP packet that held the ASCONF Chunks. 3739 * 3740 * To do this properly, we'll set the destination address of the chunk 3741 * and at the transmit time, will try look up the transport to use. 3742 * Since ASCONFs may be bundled, the correct transport may not be 3743 * created until we process the entire packet, thus this workaround. 3744 */ 3745 asconf_ack->dest = chunk->source; 3746 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3747 if (asoc->new_transport) { 3748 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3749 ((struct sctp_association *)asoc)->new_transport = NULL; 3750 } 3751 3752 return SCTP_DISPOSITION_CONSUME; 3753 } 3754 3755 /* 3756 * ADDIP Section 4.3 General rules for address manipulation 3757 * When building TLV parameters for the ASCONF Chunk that will add or 3758 * delete IP addresses the D0 to D13 rules should be applied: 3759 */ 3760 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 3761 const struct sctp_endpoint *ep, 3762 const struct sctp_association *asoc, 3763 const union sctp_subtype type, 3764 void *arg, 3765 struct sctp_cmd_seq *commands) 3766 { 3767 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3768 struct sctp_paramhdr *err_param = NULL; 3769 struct sctp_chunk *asconf_ack = arg; 3770 struct sctp_addiphdr *addip_hdr; 3771 __u32 sent_serial, rcvd_serial; 3772 struct sctp_chunk *abort; 3773 3774 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3775 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3776 SCTP_NULL()); 3777 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3778 } 3779 3780 /* ADD-IP, Section 4.1.2: 3781 * This chunk MUST be sent in an authenticated way by using 3782 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3783 * is received unauthenticated it MUST be silently discarded as 3784 * described in [I-D.ietf-tsvwg-sctp-auth]. 3785 */ 3786 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3787 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3788 commands); 3789 3790 /* Make sure that the ADDIP chunk has a valid length. */ 3791 if (!sctp_chunk_length_valid(asconf_ack, 3792 sizeof(struct sctp_addip_chunk))) 3793 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3794 commands); 3795 3796 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 3797 rcvd_serial = ntohl(addip_hdr->serial); 3798 3799 /* Verify the ASCONF-ACK chunk before processing it. */ 3800 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3801 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3802 (void *)err_param, commands); 3803 3804 if (last_asconf) { 3805 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr; 3806 sent_serial = ntohl(addip_hdr->serial); 3807 } else { 3808 sent_serial = asoc->addip_serial - 1; 3809 } 3810 3811 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3812 * equal to the next serial number to be used but no ASCONF chunk is 3813 * outstanding the endpoint MUST ABORT the association. Note that a 3814 * sequence number is greater than if it is no more than 2^^31-1 3815 * larger than the current sequence number (using serial arithmetic). 3816 */ 3817 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3818 !(asoc->addip_last_asconf)) { 3819 abort = sctp_make_abort(asoc, asconf_ack, 3820 sizeof(struct sctp_errhdr)); 3821 if (abort) { 3822 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3823 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3824 SCTP_CHUNK(abort)); 3825 } 3826 /* We are going to ABORT, so we might as well stop 3827 * processing the rest of the chunks in the packet. 3828 */ 3829 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3830 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3831 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3832 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3833 SCTP_ERROR(ECONNABORTED)); 3834 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3835 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3836 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3837 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3838 return SCTP_DISPOSITION_ABORT; 3839 } 3840 3841 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3842 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3843 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3844 3845 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3846 asconf_ack)) { 3847 /* Successfully processed ASCONF_ACK. We can 3848 * release the next asconf if we have one. 3849 */ 3850 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3851 SCTP_NULL()); 3852 return SCTP_DISPOSITION_CONSUME; 3853 } 3854 3855 abort = sctp_make_abort(asoc, asconf_ack, 3856 sizeof(struct sctp_errhdr)); 3857 if (abort) { 3858 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3859 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3860 SCTP_CHUNK(abort)); 3861 } 3862 /* We are going to ABORT, so we might as well stop 3863 * processing the rest of the chunks in the packet. 3864 */ 3865 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3866 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3867 SCTP_ERROR(ECONNABORTED)); 3868 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3869 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3870 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3871 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3872 return SCTP_DISPOSITION_ABORT; 3873 } 3874 3875 return SCTP_DISPOSITION_DISCARD; 3876 } 3877 3878 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 3879 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 3880 const struct sctp_endpoint *ep, 3881 const struct sctp_association *asoc, 3882 const union sctp_subtype type, 3883 void *arg, 3884 struct sctp_cmd_seq *commands) 3885 { 3886 struct sctp_paramhdr *err_param = NULL; 3887 struct sctp_chunk *chunk = arg; 3888 struct sctp_reconf_chunk *hdr; 3889 union sctp_params param; 3890 3891 if (!sctp_vtag_verify(chunk, asoc)) { 3892 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3893 SCTP_NULL()); 3894 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3895 } 3896 3897 /* Make sure that the RECONF chunk has a valid length. */ 3898 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 3899 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3900 commands); 3901 3902 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 3903 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3904 (void *)err_param, commands); 3905 3906 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 3907 sctp_walk_params(param, hdr, params) { 3908 struct sctp_chunk *reply = NULL; 3909 struct sctp_ulpevent *ev = NULL; 3910 3911 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 3912 reply = sctp_process_strreset_outreq( 3913 (struct sctp_association *)asoc, param, &ev); 3914 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 3915 reply = sctp_process_strreset_inreq( 3916 (struct sctp_association *)asoc, param, &ev); 3917 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 3918 reply = sctp_process_strreset_tsnreq( 3919 (struct sctp_association *)asoc, param, &ev); 3920 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 3921 reply = sctp_process_strreset_addstrm_out( 3922 (struct sctp_association *)asoc, param, &ev); 3923 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 3924 reply = sctp_process_strreset_addstrm_in( 3925 (struct sctp_association *)asoc, param, &ev); 3926 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 3927 reply = sctp_process_strreset_resp( 3928 (struct sctp_association *)asoc, param, &ev); 3929 3930 if (ev) 3931 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3932 SCTP_ULPEVENT(ev)); 3933 3934 if (reply) 3935 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3936 SCTP_CHUNK(reply)); 3937 } 3938 3939 return SCTP_DISPOSITION_CONSUME; 3940 } 3941 3942 /* 3943 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3944 * 3945 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3946 * its cumulative TSN point to the value carried in the FORWARD TSN 3947 * chunk, and then MUST further advance its cumulative TSN point locally 3948 * if possible. 3949 * After the above processing, the data receiver MUST stop reporting any 3950 * missing TSNs earlier than or equal to the new cumulative TSN point. 3951 * 3952 * Verification Tag: 8.5 Verification Tag [Normal verification] 3953 * 3954 * The return value is the disposition of the chunk. 3955 */ 3956 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 3957 const struct sctp_endpoint *ep, 3958 const struct sctp_association *asoc, 3959 const union sctp_subtype type, 3960 void *arg, 3961 struct sctp_cmd_seq *commands) 3962 { 3963 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3964 struct sctp_chunk *chunk = arg; 3965 __u16 len; 3966 __u32 tsn; 3967 3968 if (!sctp_vtag_verify(chunk, asoc)) { 3969 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3970 SCTP_NULL()); 3971 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3972 } 3973 3974 if (!asoc->peer.prsctp_capable) 3975 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 3976 3977 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3978 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 3979 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3980 commands); 3981 3982 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3983 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3984 len = ntohs(chunk->chunk_hdr->length); 3985 len -= sizeof(struct sctp_chunkhdr); 3986 skb_pull(chunk->skb, len); 3987 3988 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3989 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3990 3991 /* The TSN is too high--silently discard the chunk and count on it 3992 * getting retransmitted later. 3993 */ 3994 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3995 goto discard_noforce; 3996 3997 if (!asoc->stream.si->validate_ftsn(chunk)) 3998 goto discard_noforce; 3999 4000 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4001 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4002 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4003 SCTP_CHUNK(chunk)); 4004 4005 /* Count this as receiving DATA. */ 4006 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4007 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4008 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4009 } 4010 4011 /* FIXME: For now send a SACK, but DATA processing may 4012 * send another. 4013 */ 4014 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4015 4016 return SCTP_DISPOSITION_CONSUME; 4017 4018 discard_noforce: 4019 return SCTP_DISPOSITION_DISCARD; 4020 } 4021 4022 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4023 struct net *net, 4024 const struct sctp_endpoint *ep, 4025 const struct sctp_association *asoc, 4026 const union sctp_subtype type, 4027 void *arg, 4028 struct sctp_cmd_seq *commands) 4029 { 4030 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4031 struct sctp_chunk *chunk = arg; 4032 __u16 len; 4033 __u32 tsn; 4034 4035 if (!sctp_vtag_verify(chunk, asoc)) { 4036 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4037 SCTP_NULL()); 4038 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4039 } 4040 4041 if (!asoc->peer.prsctp_capable) 4042 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4043 4044 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4045 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4046 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4047 commands); 4048 4049 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4050 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4051 len = ntohs(chunk->chunk_hdr->length); 4052 len -= sizeof(struct sctp_chunkhdr); 4053 skb_pull(chunk->skb, len); 4054 4055 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4056 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4057 4058 /* The TSN is too high--silently discard the chunk and count on it 4059 * getting retransmitted later. 4060 */ 4061 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4062 goto gen_shutdown; 4063 4064 if (!asoc->stream.si->validate_ftsn(chunk)) 4065 goto gen_shutdown; 4066 4067 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4068 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4069 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4070 SCTP_CHUNK(chunk)); 4071 4072 /* Go a head and force a SACK, since we are shutting down. */ 4073 gen_shutdown: 4074 /* Implementor's Guide. 4075 * 4076 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4077 * respond to each received packet containing one or more DATA chunk(s) 4078 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4079 */ 4080 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4081 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4082 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4083 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4084 4085 return SCTP_DISPOSITION_CONSUME; 4086 } 4087 4088 /* 4089 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4090 * 4091 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4092 * Identifier field. If this algorithm was not specified by the 4093 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4094 * during association setup, the AUTH chunk and all chunks after it MUST 4095 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4096 * defined in Section 4.1. 4097 * 4098 * If an endpoint with no shared key receives a Shared Key Identifier 4099 * other than 0, it MUST silently discard all authenticated chunks. If 4100 * the endpoint has at least one endpoint pair shared key for the peer, 4101 * it MUST use the key specified by the Shared Key Identifier if a 4102 * key has been configured for that Shared Key Identifier. If no 4103 * endpoint pair shared key has been configured for that Shared Key 4104 * Identifier, all authenticated chunks MUST be silently discarded. 4105 * 4106 * Verification Tag: 8.5 Verification Tag [Normal verification] 4107 * 4108 * The return value is the disposition of the chunk. 4109 */ 4110 static enum sctp_ierror sctp_sf_authenticate( 4111 struct net *net, 4112 const struct sctp_endpoint *ep, 4113 const struct sctp_association *asoc, 4114 const union sctp_subtype type, 4115 struct sctp_chunk *chunk) 4116 { 4117 struct sctp_authhdr *auth_hdr; 4118 __u8 *save_digest, *digest; 4119 struct sctp_hmac *hmac; 4120 unsigned int sig_len; 4121 __u16 key_id; 4122 4123 /* Pull in the auth header, so we can do some more verification */ 4124 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4125 chunk->subh.auth_hdr = auth_hdr; 4126 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4127 4128 /* Make sure that we support the HMAC algorithm from the auth 4129 * chunk. 4130 */ 4131 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4132 return SCTP_IERROR_AUTH_BAD_HMAC; 4133 4134 /* Make sure that the provided shared key identifier has been 4135 * configured 4136 */ 4137 key_id = ntohs(auth_hdr->shkey_id); 4138 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4139 return SCTP_IERROR_AUTH_BAD_KEYID; 4140 4141 4142 /* Make sure that the length of the signature matches what 4143 * we expect. 4144 */ 4145 sig_len = ntohs(chunk->chunk_hdr->length) - 4146 sizeof(struct sctp_auth_chunk); 4147 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4148 if (sig_len != hmac->hmac_len) 4149 return SCTP_IERROR_PROTO_VIOLATION; 4150 4151 /* Now that we've done validation checks, we can compute and 4152 * verify the hmac. The steps involved are: 4153 * 1. Save the digest from the chunk. 4154 * 2. Zero out the digest in the chunk. 4155 * 3. Compute the new digest 4156 * 4. Compare saved and new digests. 4157 */ 4158 digest = auth_hdr->hmac; 4159 skb_pull(chunk->skb, sig_len); 4160 4161 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4162 if (!save_digest) 4163 goto nomem; 4164 4165 memset(digest, 0, sig_len); 4166 4167 sctp_auth_calculate_hmac(asoc, chunk->skb, 4168 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4169 GFP_ATOMIC); 4170 4171 /* Discard the packet if the digests do not match */ 4172 if (memcmp(save_digest, digest, sig_len)) { 4173 kfree(save_digest); 4174 return SCTP_IERROR_BAD_SIG; 4175 } 4176 4177 kfree(save_digest); 4178 chunk->auth = 1; 4179 4180 return SCTP_IERROR_NO_ERROR; 4181 nomem: 4182 return SCTP_IERROR_NOMEM; 4183 } 4184 4185 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4186 const struct sctp_endpoint *ep, 4187 const struct sctp_association *asoc, 4188 const union sctp_subtype type, 4189 void *arg, struct sctp_cmd_seq *commands) 4190 { 4191 struct sctp_chunk *chunk = arg; 4192 struct sctp_authhdr *auth_hdr; 4193 struct sctp_chunk *err_chunk; 4194 enum sctp_ierror error; 4195 4196 /* Make sure that the peer has AUTH capable */ 4197 if (!asoc->peer.auth_capable) 4198 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4199 4200 if (!sctp_vtag_verify(chunk, asoc)) { 4201 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4202 SCTP_NULL()); 4203 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4204 } 4205 4206 /* Make sure that the AUTH chunk has valid length. */ 4207 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4208 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4209 commands); 4210 4211 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4212 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4213 switch (error) { 4214 case SCTP_IERROR_AUTH_BAD_HMAC: 4215 /* Generate the ERROR chunk and discard the rest 4216 * of the packet 4217 */ 4218 err_chunk = sctp_make_op_error(asoc, chunk, 4219 SCTP_ERROR_UNSUP_HMAC, 4220 &auth_hdr->hmac_id, 4221 sizeof(__u16), 0); 4222 if (err_chunk) { 4223 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4224 SCTP_CHUNK(err_chunk)); 4225 } 4226 /* Fall Through */ 4227 case SCTP_IERROR_AUTH_BAD_KEYID: 4228 case SCTP_IERROR_BAD_SIG: 4229 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4230 4231 case SCTP_IERROR_PROTO_VIOLATION: 4232 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4233 commands); 4234 4235 case SCTP_IERROR_NOMEM: 4236 return SCTP_DISPOSITION_NOMEM; 4237 4238 default: /* Prevent gcc warnings */ 4239 break; 4240 } 4241 4242 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4243 struct sctp_ulpevent *ev; 4244 4245 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4246 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4247 4248 if (!ev) 4249 return -ENOMEM; 4250 4251 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4252 SCTP_ULPEVENT(ev)); 4253 } 4254 4255 return SCTP_DISPOSITION_CONSUME; 4256 } 4257 4258 /* 4259 * Process an unknown chunk. 4260 * 4261 * Section: 3.2. Also, 2.1 in the implementor's guide. 4262 * 4263 * Chunk Types are encoded such that the highest-order two bits specify 4264 * the action that must be taken if the processing endpoint does not 4265 * recognize the Chunk Type. 4266 * 4267 * 00 - Stop processing this SCTP packet and discard it, do not process 4268 * any further chunks within it. 4269 * 4270 * 01 - Stop processing this SCTP packet and discard it, do not process 4271 * any further chunks within it, and report the unrecognized 4272 * chunk in an 'Unrecognized Chunk Type'. 4273 * 4274 * 10 - Skip this chunk and continue processing. 4275 * 4276 * 11 - Skip this chunk and continue processing, but report in an ERROR 4277 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4278 * 4279 * The return value is the disposition of the chunk. 4280 */ 4281 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4282 const struct sctp_endpoint *ep, 4283 const struct sctp_association *asoc, 4284 const union sctp_subtype type, 4285 void *arg, 4286 struct sctp_cmd_seq *commands) 4287 { 4288 struct sctp_chunk *unk_chunk = arg; 4289 struct sctp_chunk *err_chunk; 4290 struct sctp_chunkhdr *hdr; 4291 4292 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4293 4294 if (!sctp_vtag_verify(unk_chunk, asoc)) 4295 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4296 4297 /* Make sure that the chunk has a valid length. 4298 * Since we don't know the chunk type, we use a general 4299 * chunkhdr structure to make a comparison. 4300 */ 4301 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4302 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4303 commands); 4304 4305 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4306 case SCTP_CID_ACTION_DISCARD: 4307 /* Discard the packet. */ 4308 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4309 case SCTP_CID_ACTION_DISCARD_ERR: 4310 /* Generate an ERROR chunk as response. */ 4311 hdr = unk_chunk->chunk_hdr; 4312 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4313 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4314 SCTP_PAD4(ntohs(hdr->length)), 4315 0); 4316 if (err_chunk) { 4317 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4318 SCTP_CHUNK(err_chunk)); 4319 } 4320 4321 /* Discard the packet. */ 4322 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4323 return SCTP_DISPOSITION_CONSUME; 4324 case SCTP_CID_ACTION_SKIP: 4325 /* Skip the chunk. */ 4326 return SCTP_DISPOSITION_DISCARD; 4327 case SCTP_CID_ACTION_SKIP_ERR: 4328 /* Generate an ERROR chunk as response. */ 4329 hdr = unk_chunk->chunk_hdr; 4330 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4331 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4332 SCTP_PAD4(ntohs(hdr->length)), 4333 0); 4334 if (err_chunk) { 4335 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4336 SCTP_CHUNK(err_chunk)); 4337 } 4338 /* Skip the chunk. */ 4339 return SCTP_DISPOSITION_CONSUME; 4340 default: 4341 break; 4342 } 4343 4344 return SCTP_DISPOSITION_DISCARD; 4345 } 4346 4347 /* 4348 * Discard the chunk. 4349 * 4350 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4351 * [Too numerous to mention...] 4352 * Verification Tag: No verification needed. 4353 * Inputs 4354 * (endpoint, asoc, chunk) 4355 * 4356 * Outputs 4357 * (asoc, reply_msg, msg_up, timers, counters) 4358 * 4359 * The return value is the disposition of the chunk. 4360 */ 4361 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4362 const struct sctp_endpoint *ep, 4363 const struct sctp_association *asoc, 4364 const union sctp_subtype type, 4365 void *arg, 4366 struct sctp_cmd_seq *commands) 4367 { 4368 struct sctp_chunk *chunk = arg; 4369 4370 /* Make sure that the chunk has a valid length. 4371 * Since we don't know the chunk type, we use a general 4372 * chunkhdr structure to make a comparison. 4373 */ 4374 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4375 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4376 commands); 4377 4378 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4379 4380 return SCTP_DISPOSITION_DISCARD; 4381 } 4382 4383 /* 4384 * Discard the whole packet. 4385 * 4386 * Section: 8.4 2) 4387 * 4388 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4389 * silently discard the OOTB packet and take no further action. 4390 * 4391 * Verification Tag: No verification necessary 4392 * 4393 * Inputs 4394 * (endpoint, asoc, chunk) 4395 * 4396 * Outputs 4397 * (asoc, reply_msg, msg_up, timers, counters) 4398 * 4399 * The return value is the disposition of the chunk. 4400 */ 4401 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4402 const struct sctp_endpoint *ep, 4403 const struct sctp_association *asoc, 4404 const union sctp_subtype type, 4405 void *arg, struct sctp_cmd_seq *commands) 4406 { 4407 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4408 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4409 4410 return SCTP_DISPOSITION_CONSUME; 4411 } 4412 4413 4414 /* 4415 * The other end is violating protocol. 4416 * 4417 * Section: Not specified 4418 * Verification Tag: Not specified 4419 * Inputs 4420 * (endpoint, asoc, chunk) 4421 * 4422 * Outputs 4423 * (asoc, reply_msg, msg_up, timers, counters) 4424 * 4425 * We simply tag the chunk as a violation. The state machine will log 4426 * the violation and continue. 4427 */ 4428 enum sctp_disposition sctp_sf_violation(struct net *net, 4429 const struct sctp_endpoint *ep, 4430 const struct sctp_association *asoc, 4431 const union sctp_subtype type, 4432 void *arg, 4433 struct sctp_cmd_seq *commands) 4434 { 4435 struct sctp_chunk *chunk = arg; 4436 4437 /* Make sure that the chunk has a valid length. */ 4438 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4439 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4440 commands); 4441 4442 return SCTP_DISPOSITION_VIOLATION; 4443 } 4444 4445 /* 4446 * Common function to handle a protocol violation. 4447 */ 4448 static enum sctp_disposition sctp_sf_abort_violation( 4449 struct net *net, 4450 const struct sctp_endpoint *ep, 4451 const struct sctp_association *asoc, 4452 void *arg, 4453 struct sctp_cmd_seq *commands, 4454 const __u8 *payload, 4455 const size_t paylen) 4456 { 4457 struct sctp_packet *packet = NULL; 4458 struct sctp_chunk *chunk = arg; 4459 struct sctp_chunk *abort = NULL; 4460 4461 /* SCTP-AUTH, Section 6.3: 4462 * It should be noted that if the receiver wants to tear 4463 * down an association in an authenticated way only, the 4464 * handling of malformed packets should not result in 4465 * tearing down the association. 4466 * 4467 * This means that if we only want to abort associations 4468 * in an authenticated way (i.e AUTH+ABORT), then we 4469 * can't destroy this association just because the packet 4470 * was malformed. 4471 */ 4472 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4473 goto discard; 4474 4475 /* Make the abort chunk. */ 4476 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4477 if (!abort) 4478 goto nomem; 4479 4480 if (asoc) { 4481 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4482 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4483 !asoc->peer.i.init_tag) { 4484 struct sctp_initack_chunk *initack; 4485 4486 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4487 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4488 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4489 else { 4490 unsigned int inittag; 4491 4492 inittag = ntohl(initack->init_hdr.init_tag); 4493 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4494 SCTP_U32(inittag)); 4495 } 4496 } 4497 4498 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4499 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4500 4501 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4502 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4503 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4504 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4505 SCTP_ERROR(ECONNREFUSED)); 4506 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4507 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4508 } else { 4509 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4510 SCTP_ERROR(ECONNABORTED)); 4511 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4512 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4513 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4514 } 4515 } else { 4516 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4517 4518 if (!packet) 4519 goto nomem_pkt; 4520 4521 if (sctp_test_T_bit(abort)) 4522 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4523 4524 abort->skb->sk = ep->base.sk; 4525 4526 sctp_packet_append_chunk(packet, abort); 4527 4528 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4529 SCTP_PACKET(packet)); 4530 4531 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4532 } 4533 4534 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4535 4536 discard: 4537 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4538 return SCTP_DISPOSITION_ABORT; 4539 4540 nomem_pkt: 4541 sctp_chunk_free(abort); 4542 nomem: 4543 return SCTP_DISPOSITION_NOMEM; 4544 } 4545 4546 /* 4547 * Handle a protocol violation when the chunk length is invalid. 4548 * "Invalid" length is identified as smaller than the minimal length a 4549 * given chunk can be. For example, a SACK chunk has invalid length 4550 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4551 * 4552 * We inform the other end by sending an ABORT with a Protocol Violation 4553 * error code. 4554 * 4555 * Section: Not specified 4556 * Verification Tag: Nothing to do 4557 * Inputs 4558 * (endpoint, asoc, chunk) 4559 * 4560 * Outputs 4561 * (reply_msg, msg_up, counters) 4562 * 4563 * Generate an ABORT chunk and terminate the association. 4564 */ 4565 static enum sctp_disposition sctp_sf_violation_chunklen( 4566 struct net *net, 4567 const struct sctp_endpoint *ep, 4568 const struct sctp_association *asoc, 4569 const union sctp_subtype type, 4570 void *arg, 4571 struct sctp_cmd_seq *commands) 4572 { 4573 static const char err_str[] = "The following chunk had invalid length:"; 4574 4575 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4576 sizeof(err_str)); 4577 } 4578 4579 /* 4580 * Handle a protocol violation when the parameter length is invalid. 4581 * If the length is smaller than the minimum length of a given parameter, 4582 * or accumulated length in multi parameters exceeds the end of the chunk, 4583 * the length is considered as invalid. 4584 */ 4585 static enum sctp_disposition sctp_sf_violation_paramlen( 4586 struct net *net, 4587 const struct sctp_endpoint *ep, 4588 const struct sctp_association *asoc, 4589 const union sctp_subtype type, 4590 void *arg, void *ext, 4591 struct sctp_cmd_seq *commands) 4592 { 4593 struct sctp_paramhdr *param = ext; 4594 struct sctp_chunk *abort = NULL; 4595 struct sctp_chunk *chunk = arg; 4596 4597 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4598 goto discard; 4599 4600 /* Make the abort chunk. */ 4601 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4602 if (!abort) 4603 goto nomem; 4604 4605 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4606 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4607 4608 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4609 SCTP_ERROR(ECONNABORTED)); 4610 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4611 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4612 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4613 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4614 4615 discard: 4616 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4617 return SCTP_DISPOSITION_ABORT; 4618 nomem: 4619 return SCTP_DISPOSITION_NOMEM; 4620 } 4621 4622 /* Handle a protocol violation when the peer trying to advance the 4623 * cumulative tsn ack to a point beyond the max tsn currently sent. 4624 * 4625 * We inform the other end by sending an ABORT with a Protocol Violation 4626 * error code. 4627 */ 4628 static enum sctp_disposition sctp_sf_violation_ctsn( 4629 struct net *net, 4630 const struct sctp_endpoint *ep, 4631 const struct sctp_association *asoc, 4632 const union sctp_subtype type, 4633 void *arg, 4634 struct sctp_cmd_seq *commands) 4635 { 4636 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4637 4638 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4639 sizeof(err_str)); 4640 } 4641 4642 /* Handle protocol violation of an invalid chunk bundling. For example, 4643 * when we have an association and we receive bundled INIT-ACK, or 4644 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4645 * statement from the specs. Additionally, there might be an attacker 4646 * on the path and we may not want to continue this communication. 4647 */ 4648 static enum sctp_disposition sctp_sf_violation_chunk( 4649 struct net *net, 4650 const struct sctp_endpoint *ep, 4651 const struct sctp_association *asoc, 4652 const union sctp_subtype type, 4653 void *arg, 4654 struct sctp_cmd_seq *commands) 4655 { 4656 static const char err_str[] = "The following chunk violates protocol:"; 4657 4658 if (!asoc) 4659 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4660 4661 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4662 sizeof(err_str)); 4663 } 4664 /*************************************************************************** 4665 * These are the state functions for handling primitive (Section 10) events. 4666 ***************************************************************************/ 4667 /* 4668 * sctp_sf_do_prm_asoc 4669 * 4670 * Section: 10.1 ULP-to-SCTP 4671 * B) Associate 4672 * 4673 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4674 * outbound stream count) 4675 * -> association id [,destination transport addr list] [,outbound stream 4676 * count] 4677 * 4678 * This primitive allows the upper layer to initiate an association to a 4679 * specific peer endpoint. 4680 * 4681 * The peer endpoint shall be specified by one of the transport addresses 4682 * which defines the endpoint (see Section 1.4). If the local SCTP 4683 * instance has not been initialized, the ASSOCIATE is considered an 4684 * error. 4685 * [This is not relevant for the kernel implementation since we do all 4686 * initialization at boot time. It we hadn't initialized we wouldn't 4687 * get anywhere near this code.] 4688 * 4689 * An association id, which is a local handle to the SCTP association, 4690 * will be returned on successful establishment of the association. If 4691 * SCTP is not able to open an SCTP association with the peer endpoint, 4692 * an error is returned. 4693 * [In the kernel implementation, the struct sctp_association needs to 4694 * be created BEFORE causing this primitive to run.] 4695 * 4696 * Other association parameters may be returned, including the 4697 * complete destination transport addresses of the peer as well as the 4698 * outbound stream count of the local endpoint. One of the transport 4699 * address from the returned destination addresses will be selected by 4700 * the local endpoint as default primary path for sending SCTP packets 4701 * to this peer. The returned "destination transport addr list" can 4702 * be used by the ULP to change the default primary path or to force 4703 * sending a packet to a specific transport address. [All of this 4704 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4705 * function.] 4706 * 4707 * Mandatory attributes: 4708 * 4709 * o local SCTP instance name - obtained from the INITIALIZE operation. 4710 * [This is the argument asoc.] 4711 * o destination transport addr - specified as one of the transport 4712 * addresses of the peer endpoint with which the association is to be 4713 * established. 4714 * [This is asoc->peer.active_path.] 4715 * o outbound stream count - the number of outbound streams the ULP 4716 * would like to open towards this peer endpoint. 4717 * [BUG: This is not currently implemented.] 4718 * Optional attributes: 4719 * 4720 * None. 4721 * 4722 * The return value is a disposition. 4723 */ 4724 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4725 const struct sctp_endpoint *ep, 4726 const struct sctp_association *asoc, 4727 const union sctp_subtype type, 4728 void *arg, 4729 struct sctp_cmd_seq *commands) 4730 { 4731 struct sctp_association *my_asoc; 4732 struct sctp_chunk *repl; 4733 4734 /* The comment below says that we enter COOKIE-WAIT AFTER 4735 * sending the INIT, but that doesn't actually work in our 4736 * implementation... 4737 */ 4738 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4739 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4740 4741 /* RFC 2960 5.1 Normal Establishment of an Association 4742 * 4743 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4744 * must provide its Verification Tag (Tag_A) in the Initiate 4745 * Tag field. Tag_A SHOULD be a random number in the range of 4746 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4747 */ 4748 4749 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4750 if (!repl) 4751 goto nomem; 4752 4753 /* Choose transport for INIT. */ 4754 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4755 SCTP_CHUNK(repl)); 4756 4757 /* Cast away the const modifier, as we want to just 4758 * rerun it through as a sideffect. 4759 */ 4760 my_asoc = (struct sctp_association *)asoc; 4761 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4762 4763 /* After sending the INIT, "A" starts the T1-init timer and 4764 * enters the COOKIE-WAIT state. 4765 */ 4766 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4767 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4768 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4769 return SCTP_DISPOSITION_CONSUME; 4770 4771 nomem: 4772 return SCTP_DISPOSITION_NOMEM; 4773 } 4774 4775 /* 4776 * Process the SEND primitive. 4777 * 4778 * Section: 10.1 ULP-to-SCTP 4779 * E) Send 4780 * 4781 * Format: SEND(association id, buffer address, byte count [,context] 4782 * [,stream id] [,life time] [,destination transport address] 4783 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4784 * -> result 4785 * 4786 * This is the main method to send user data via SCTP. 4787 * 4788 * Mandatory attributes: 4789 * 4790 * o association id - local handle to the SCTP association 4791 * 4792 * o buffer address - the location where the user message to be 4793 * transmitted is stored; 4794 * 4795 * o byte count - The size of the user data in number of bytes; 4796 * 4797 * Optional attributes: 4798 * 4799 * o context - an optional 32 bit integer that will be carried in the 4800 * sending failure notification to the ULP if the transportation of 4801 * this User Message fails. 4802 * 4803 * o stream id - to indicate which stream to send the data on. If not 4804 * specified, stream 0 will be used. 4805 * 4806 * o life time - specifies the life time of the user data. The user data 4807 * will not be sent by SCTP after the life time expires. This 4808 * parameter can be used to avoid efforts to transmit stale 4809 * user messages. SCTP notifies the ULP if the data cannot be 4810 * initiated to transport (i.e. sent to the destination via SCTP's 4811 * send primitive) within the life time variable. However, the 4812 * user data will be transmitted if SCTP has attempted to transmit a 4813 * chunk before the life time expired. 4814 * 4815 * o destination transport address - specified as one of the destination 4816 * transport addresses of the peer endpoint to which this packet 4817 * should be sent. Whenever possible, SCTP should use this destination 4818 * transport address for sending the packets, instead of the current 4819 * primary path. 4820 * 4821 * o unorder flag - this flag, if present, indicates that the user 4822 * would like the data delivered in an unordered fashion to the peer 4823 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4824 * message). 4825 * 4826 * o no-bundle flag - instructs SCTP not to bundle this user data with 4827 * other outbound DATA chunks. SCTP MAY still bundle even when 4828 * this flag is present, when faced with network congestion. 4829 * 4830 * o payload protocol-id - A 32 bit unsigned integer that is to be 4831 * passed to the peer indicating the type of payload protocol data 4832 * being transmitted. This value is passed as opaque data by SCTP. 4833 * 4834 * The return value is the disposition. 4835 */ 4836 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 4837 const struct sctp_endpoint *ep, 4838 const struct sctp_association *asoc, 4839 const union sctp_subtype type, 4840 void *arg, 4841 struct sctp_cmd_seq *commands) 4842 { 4843 struct sctp_datamsg *msg = arg; 4844 4845 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4846 return SCTP_DISPOSITION_CONSUME; 4847 } 4848 4849 /* 4850 * Process the SHUTDOWN primitive. 4851 * 4852 * Section: 10.1: 4853 * C) Shutdown 4854 * 4855 * Format: SHUTDOWN(association id) 4856 * -> result 4857 * 4858 * Gracefully closes an association. Any locally queued user data 4859 * will be delivered to the peer. The association will be terminated only 4860 * after the peer acknowledges all the SCTP packets sent. A success code 4861 * will be returned on successful termination of the association. If 4862 * attempting to terminate the association results in a failure, an error 4863 * code shall be returned. 4864 * 4865 * Mandatory attributes: 4866 * 4867 * o association id - local handle to the SCTP association 4868 * 4869 * Optional attributes: 4870 * 4871 * None. 4872 * 4873 * The return value is the disposition. 4874 */ 4875 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 4876 struct net *net, 4877 const struct sctp_endpoint *ep, 4878 const struct sctp_association *asoc, 4879 const union sctp_subtype type, 4880 void *arg, 4881 struct sctp_cmd_seq *commands) 4882 { 4883 enum sctp_disposition disposition; 4884 4885 /* From 9.2 Shutdown of an Association 4886 * Upon receipt of the SHUTDOWN primitive from its upper 4887 * layer, the endpoint enters SHUTDOWN-PENDING state and 4888 * remains there until all outstanding data has been 4889 * acknowledged by its peer. The endpoint accepts no new data 4890 * from its upper layer, but retransmits data to the far end 4891 * if necessary to fill gaps. 4892 */ 4893 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4894 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4895 4896 disposition = SCTP_DISPOSITION_CONSUME; 4897 if (sctp_outq_is_empty(&asoc->outqueue)) { 4898 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4899 arg, commands); 4900 } 4901 4902 return disposition; 4903 } 4904 4905 /* 4906 * Process the ABORT primitive. 4907 * 4908 * Section: 10.1: 4909 * C) Abort 4910 * 4911 * Format: Abort(association id [, cause code]) 4912 * -> result 4913 * 4914 * Ungracefully closes an association. Any locally queued user data 4915 * will be discarded and an ABORT chunk is sent to the peer. A success code 4916 * will be returned on successful abortion of the association. If 4917 * attempting to abort the association results in a failure, an error 4918 * code shall be returned. 4919 * 4920 * Mandatory attributes: 4921 * 4922 * o association id - local handle to the SCTP association 4923 * 4924 * Optional attributes: 4925 * 4926 * o cause code - reason of the abort to be passed to the peer 4927 * 4928 * None. 4929 * 4930 * The return value is the disposition. 4931 */ 4932 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 4933 struct net *net, 4934 const struct sctp_endpoint *ep, 4935 const struct sctp_association *asoc, 4936 const union sctp_subtype type, 4937 void *arg, 4938 struct sctp_cmd_seq *commands) 4939 { 4940 /* From 9.1 Abort of an Association 4941 * Upon receipt of the ABORT primitive from its upper 4942 * layer, the endpoint enters CLOSED state and 4943 * discard all outstanding data has been 4944 * acknowledged by its peer. The endpoint accepts no new data 4945 * from its upper layer, but retransmits data to the far end 4946 * if necessary to fill gaps. 4947 */ 4948 struct sctp_chunk *abort = arg; 4949 4950 if (abort) 4951 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4952 4953 /* Even if we can't send the ABORT due to low memory delete the 4954 * TCB. This is a departure from our typical NOMEM handling. 4955 */ 4956 4957 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4958 SCTP_ERROR(ECONNABORTED)); 4959 /* Delete the established association. */ 4960 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4961 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4962 4963 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4964 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4965 4966 return SCTP_DISPOSITION_ABORT; 4967 } 4968 4969 /* We tried an illegal operation on an association which is closed. */ 4970 enum sctp_disposition sctp_sf_error_closed(struct net *net, 4971 const struct sctp_endpoint *ep, 4972 const struct sctp_association *asoc, 4973 const union sctp_subtype type, 4974 void *arg, 4975 struct sctp_cmd_seq *commands) 4976 { 4977 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4978 return SCTP_DISPOSITION_CONSUME; 4979 } 4980 4981 /* We tried an illegal operation on an association which is shutting 4982 * down. 4983 */ 4984 enum sctp_disposition sctp_sf_error_shutdown( 4985 struct net *net, 4986 const struct sctp_endpoint *ep, 4987 const struct sctp_association *asoc, 4988 const union sctp_subtype type, 4989 void *arg, 4990 struct sctp_cmd_seq *commands) 4991 { 4992 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4993 SCTP_ERROR(-ESHUTDOWN)); 4994 return SCTP_DISPOSITION_CONSUME; 4995 } 4996 4997 /* 4998 * sctp_cookie_wait_prm_shutdown 4999 * 5000 * Section: 4 Note: 2 5001 * Verification Tag: 5002 * Inputs 5003 * (endpoint, asoc) 5004 * 5005 * The RFC does not explicitly address this issue, but is the route through the 5006 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5007 * 5008 * Outputs 5009 * (timers) 5010 */ 5011 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5012 struct net *net, 5013 const struct sctp_endpoint *ep, 5014 const struct sctp_association *asoc, 5015 const union sctp_subtype type, 5016 void *arg, 5017 struct sctp_cmd_seq *commands) 5018 { 5019 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5020 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5021 5022 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5023 SCTP_STATE(SCTP_STATE_CLOSED)); 5024 5025 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5026 5027 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5028 5029 return SCTP_DISPOSITION_DELETE_TCB; 5030 } 5031 5032 /* 5033 * sctp_cookie_echoed_prm_shutdown 5034 * 5035 * Section: 4 Note: 2 5036 * Verification Tag: 5037 * Inputs 5038 * (endpoint, asoc) 5039 * 5040 * The RFC does not explcitly address this issue, but is the route through the 5041 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5042 * 5043 * Outputs 5044 * (timers) 5045 */ 5046 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5047 struct net *net, 5048 const struct sctp_endpoint *ep, 5049 const struct sctp_association *asoc, 5050 const union sctp_subtype type, 5051 void *arg, 5052 struct sctp_cmd_seq *commands) 5053 { 5054 /* There is a single T1 timer, so we should be able to use 5055 * common function with the COOKIE-WAIT state. 5056 */ 5057 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5058 } 5059 5060 /* 5061 * sctp_sf_cookie_wait_prm_abort 5062 * 5063 * Section: 4 Note: 2 5064 * Verification Tag: 5065 * Inputs 5066 * (endpoint, asoc) 5067 * 5068 * The RFC does not explicitly address this issue, but is the route through the 5069 * state table when someone issues an abort while in COOKIE_WAIT state. 5070 * 5071 * Outputs 5072 * (timers) 5073 */ 5074 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5075 struct net *net, 5076 const struct sctp_endpoint *ep, 5077 const struct sctp_association *asoc, 5078 const union sctp_subtype type, 5079 void *arg, 5080 struct sctp_cmd_seq *commands) 5081 { 5082 struct sctp_chunk *abort = arg; 5083 5084 /* Stop T1-init timer */ 5085 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5086 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5087 5088 if (abort) 5089 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5090 5091 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5092 SCTP_STATE(SCTP_STATE_CLOSED)); 5093 5094 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5095 5096 /* Even if we can't send the ABORT due to low memory delete the 5097 * TCB. This is a departure from our typical NOMEM handling. 5098 */ 5099 5100 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5101 SCTP_ERROR(ECONNREFUSED)); 5102 /* Delete the established association. */ 5103 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5104 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5105 5106 return SCTP_DISPOSITION_ABORT; 5107 } 5108 5109 /* 5110 * sctp_sf_cookie_echoed_prm_abort 5111 * 5112 * Section: 4 Note: 3 5113 * Verification Tag: 5114 * Inputs 5115 * (endpoint, asoc) 5116 * 5117 * The RFC does not explcitly address this issue, but is the route through the 5118 * state table when someone issues an abort while in COOKIE_ECHOED state. 5119 * 5120 * Outputs 5121 * (timers) 5122 */ 5123 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5124 struct net *net, 5125 const struct sctp_endpoint *ep, 5126 const struct sctp_association *asoc, 5127 const union sctp_subtype type, 5128 void *arg, 5129 struct sctp_cmd_seq *commands) 5130 { 5131 /* There is a single T1 timer, so we should be able to use 5132 * common function with the COOKIE-WAIT state. 5133 */ 5134 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5135 } 5136 5137 /* 5138 * sctp_sf_shutdown_pending_prm_abort 5139 * 5140 * Inputs 5141 * (endpoint, asoc) 5142 * 5143 * The RFC does not explicitly address this issue, but is the route through the 5144 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5145 * 5146 * Outputs 5147 * (timers) 5148 */ 5149 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5150 struct net *net, 5151 const struct sctp_endpoint *ep, 5152 const struct sctp_association *asoc, 5153 const union sctp_subtype type, 5154 void *arg, 5155 struct sctp_cmd_seq *commands) 5156 { 5157 /* Stop the T5-shutdown guard timer. */ 5158 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5159 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5160 5161 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5162 } 5163 5164 /* 5165 * sctp_sf_shutdown_sent_prm_abort 5166 * 5167 * Inputs 5168 * (endpoint, asoc) 5169 * 5170 * The RFC does not explicitly address this issue, but is the route through the 5171 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5172 * 5173 * Outputs 5174 * (timers) 5175 */ 5176 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5177 struct net *net, 5178 const struct sctp_endpoint *ep, 5179 const struct sctp_association *asoc, 5180 const union sctp_subtype type, 5181 void *arg, 5182 struct sctp_cmd_seq *commands) 5183 { 5184 /* Stop the T2-shutdown timer. */ 5185 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5186 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5187 5188 /* Stop the T5-shutdown guard timer. */ 5189 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5190 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5191 5192 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5193 } 5194 5195 /* 5196 * sctp_sf_cookie_echoed_prm_abort 5197 * 5198 * Inputs 5199 * (endpoint, asoc) 5200 * 5201 * The RFC does not explcitly address this issue, but is the route through the 5202 * state table when someone issues an abort while in COOKIE_ECHOED state. 5203 * 5204 * Outputs 5205 * (timers) 5206 */ 5207 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5208 struct net *net, 5209 const struct sctp_endpoint *ep, 5210 const struct sctp_association *asoc, 5211 const union sctp_subtype type, 5212 void *arg, 5213 struct sctp_cmd_seq *commands) 5214 { 5215 /* The same T2 timer, so we should be able to use 5216 * common function with the SHUTDOWN-SENT state. 5217 */ 5218 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5219 } 5220 5221 /* 5222 * Process the REQUESTHEARTBEAT primitive 5223 * 5224 * 10.1 ULP-to-SCTP 5225 * J) Request Heartbeat 5226 * 5227 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5228 * 5229 * -> result 5230 * 5231 * Instructs the local endpoint to perform a HeartBeat on the specified 5232 * destination transport address of the given association. The returned 5233 * result should indicate whether the transmission of the HEARTBEAT 5234 * chunk to the destination address is successful. 5235 * 5236 * Mandatory attributes: 5237 * 5238 * o association id - local handle to the SCTP association 5239 * 5240 * o destination transport address - the transport address of the 5241 * association on which a heartbeat should be issued. 5242 */ 5243 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5244 struct net *net, 5245 const struct sctp_endpoint *ep, 5246 const struct sctp_association *asoc, 5247 const union sctp_subtype type, 5248 void *arg, 5249 struct sctp_cmd_seq *commands) 5250 { 5251 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5252 (struct sctp_transport *)arg, commands)) 5253 return SCTP_DISPOSITION_NOMEM; 5254 5255 /* 5256 * RFC 2960 (bis), section 8.3 5257 * 5258 * D) Request an on-demand HEARTBEAT on a specific destination 5259 * transport address of a given association. 5260 * 5261 * The endpoint should increment the respective error counter of 5262 * the destination transport address each time a HEARTBEAT is sent 5263 * to that address and not acknowledged within one RTO. 5264 * 5265 */ 5266 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5267 SCTP_TRANSPORT(arg)); 5268 return SCTP_DISPOSITION_CONSUME; 5269 } 5270 5271 /* 5272 * ADDIP Section 4.1 ASCONF Chunk Procedures 5273 * When an endpoint has an ASCONF signaled change to be sent to the 5274 * remote endpoint it should do A1 to A9 5275 */ 5276 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5277 const struct sctp_endpoint *ep, 5278 const struct sctp_association *asoc, 5279 const union sctp_subtype type, 5280 void *arg, 5281 struct sctp_cmd_seq *commands) 5282 { 5283 struct sctp_chunk *chunk = arg; 5284 5285 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5286 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5287 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5288 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5289 return SCTP_DISPOSITION_CONSUME; 5290 } 5291 5292 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5293 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5294 const struct sctp_endpoint *ep, 5295 const struct sctp_association *asoc, 5296 const union sctp_subtype type, 5297 void *arg, 5298 struct sctp_cmd_seq *commands) 5299 { 5300 struct sctp_chunk *chunk = arg; 5301 5302 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5303 return SCTP_DISPOSITION_CONSUME; 5304 } 5305 5306 /* 5307 * Ignore the primitive event 5308 * 5309 * The return value is the disposition of the primitive. 5310 */ 5311 enum sctp_disposition sctp_sf_ignore_primitive( 5312 struct net *net, 5313 const struct sctp_endpoint *ep, 5314 const struct sctp_association *asoc, 5315 const union sctp_subtype type, 5316 void *arg, 5317 struct sctp_cmd_seq *commands) 5318 { 5319 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5320 type.primitive); 5321 5322 return SCTP_DISPOSITION_DISCARD; 5323 } 5324 5325 /*************************************************************************** 5326 * These are the state functions for the OTHER events. 5327 ***************************************************************************/ 5328 5329 /* 5330 * When the SCTP stack has no more user data to send or retransmit, this 5331 * notification is given to the user. Also, at the time when a user app 5332 * subscribes to this event, if there is no data to be sent or 5333 * retransmit, the stack will immediately send up this notification. 5334 */ 5335 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5336 struct net *net, 5337 const struct sctp_endpoint *ep, 5338 const struct sctp_association *asoc, 5339 const union sctp_subtype type, 5340 void *arg, 5341 struct sctp_cmd_seq *commands) 5342 { 5343 struct sctp_ulpevent *event; 5344 5345 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5346 if (!event) 5347 return SCTP_DISPOSITION_NOMEM; 5348 5349 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5350 5351 return SCTP_DISPOSITION_CONSUME; 5352 } 5353 5354 /* 5355 * Start the shutdown negotiation. 5356 * 5357 * From Section 9.2: 5358 * Once all its outstanding data has been acknowledged, the endpoint 5359 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5360 * TSN Ack field the last sequential TSN it has received from the peer. 5361 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5362 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5363 * with the updated last sequential TSN received from its peer. 5364 * 5365 * The return value is the disposition. 5366 */ 5367 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5368 struct net *net, 5369 const struct sctp_endpoint *ep, 5370 const struct sctp_association *asoc, 5371 const union sctp_subtype type, 5372 void *arg, 5373 struct sctp_cmd_seq *commands) 5374 { 5375 struct sctp_chunk *reply; 5376 5377 /* Once all its outstanding data has been acknowledged, the 5378 * endpoint shall send a SHUTDOWN chunk to its peer including 5379 * in the Cumulative TSN Ack field the last sequential TSN it 5380 * has received from the peer. 5381 */ 5382 reply = sctp_make_shutdown(asoc, NULL); 5383 if (!reply) 5384 goto nomem; 5385 5386 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5387 * T2-shutdown timer. 5388 */ 5389 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5390 5391 /* It shall then start the T2-shutdown timer */ 5392 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5393 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5394 5395 /* RFC 4960 Section 9.2 5396 * The sender of the SHUTDOWN MAY also start an overall guard timer 5397 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5398 */ 5399 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5400 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5401 5402 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5403 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5404 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5405 5406 /* and enter the SHUTDOWN-SENT state. */ 5407 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5408 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5409 5410 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5411 * 5412 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5413 * or SHUTDOWN-ACK. 5414 */ 5415 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5416 5417 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5418 5419 return SCTP_DISPOSITION_CONSUME; 5420 5421 nomem: 5422 return SCTP_DISPOSITION_NOMEM; 5423 } 5424 5425 /* 5426 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5427 * 5428 * From Section 9.2: 5429 * 5430 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5431 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5432 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5433 * endpoint must re-send the SHUTDOWN ACK. 5434 * 5435 * The return value is the disposition. 5436 */ 5437 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5438 struct net *net, 5439 const struct sctp_endpoint *ep, 5440 const struct sctp_association *asoc, 5441 const union sctp_subtype type, 5442 void *arg, 5443 struct sctp_cmd_seq *commands) 5444 { 5445 struct sctp_chunk *chunk = arg; 5446 struct sctp_chunk *reply; 5447 5448 /* There are 2 ways of getting here: 5449 * 1) called in response to a SHUTDOWN chunk 5450 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5451 * 5452 * For the case (2), the arg parameter is set to NULL. We need 5453 * to check that we have a chunk before accessing it's fields. 5454 */ 5455 if (chunk) { 5456 if (!sctp_vtag_verify(chunk, asoc)) 5457 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5458 commands); 5459 5460 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5461 if (!sctp_chunk_length_valid( 5462 chunk, sizeof(struct sctp_shutdown_chunk))) 5463 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5464 arg, commands); 5465 } 5466 5467 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5468 * shall send a SHUTDOWN ACK ... 5469 */ 5470 reply = sctp_make_shutdown_ack(asoc, chunk); 5471 if (!reply) 5472 goto nomem; 5473 5474 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5475 * the T2-shutdown timer. 5476 */ 5477 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5478 5479 /* and start/restart a T2-shutdown timer of its own, */ 5480 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5481 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5482 5483 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5484 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5485 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5486 5487 /* Enter the SHUTDOWN-ACK-SENT state. */ 5488 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5489 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5490 5491 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5492 * 5493 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5494 * or SHUTDOWN-ACK. 5495 */ 5496 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5497 5498 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5499 5500 return SCTP_DISPOSITION_CONSUME; 5501 5502 nomem: 5503 return SCTP_DISPOSITION_NOMEM; 5504 } 5505 5506 /* 5507 * Ignore the event defined as other 5508 * 5509 * The return value is the disposition of the event. 5510 */ 5511 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5512 const struct sctp_endpoint *ep, 5513 const struct sctp_association *asoc, 5514 const union sctp_subtype type, 5515 void *arg, 5516 struct sctp_cmd_seq *commands) 5517 { 5518 pr_debug("%s: the event other type:%d is ignored\n", 5519 __func__, type.other); 5520 5521 return SCTP_DISPOSITION_DISCARD; 5522 } 5523 5524 /************************************************************ 5525 * These are the state functions for handling timeout events. 5526 ************************************************************/ 5527 5528 /* 5529 * RTX Timeout 5530 * 5531 * Section: 6.3.3 Handle T3-rtx Expiration 5532 * 5533 * Whenever the retransmission timer T3-rtx expires for a destination 5534 * address, do the following: 5535 * [See below] 5536 * 5537 * The return value is the disposition of the chunk. 5538 */ 5539 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5540 const struct sctp_endpoint *ep, 5541 const struct sctp_association *asoc, 5542 const union sctp_subtype type, 5543 void *arg, 5544 struct sctp_cmd_seq *commands) 5545 { 5546 struct sctp_transport *transport = arg; 5547 5548 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5549 5550 if (asoc->overall_error_count >= asoc->max_retrans) { 5551 if (asoc->peer.zero_window_announced && 5552 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5553 /* 5554 * We are here likely because the receiver had its rwnd 5555 * closed for a while and we have not been able to 5556 * transmit the locally queued data within the maximum 5557 * retransmission attempts limit. Start the T5 5558 * shutdown guard timer to give the receiver one last 5559 * chance and some additional time to recover before 5560 * aborting. 5561 */ 5562 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5563 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5564 } else { 5565 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5566 SCTP_ERROR(ETIMEDOUT)); 5567 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5568 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5569 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5570 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5571 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5572 return SCTP_DISPOSITION_DELETE_TCB; 5573 } 5574 } 5575 5576 /* E1) For the destination address for which the timer 5577 * expires, adjust its ssthresh with rules defined in Section 5578 * 7.2.3 and set the cwnd <- MTU. 5579 */ 5580 5581 /* E2) For the destination address for which the timer 5582 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5583 * maximum value discussed in rule C7 above (RTO.max) may be 5584 * used to provide an upper bound to this doubling operation. 5585 */ 5586 5587 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5588 * outstanding DATA chunks for the address for which the 5589 * T3-rtx has expired will fit into a single packet, subject 5590 * to the MTU constraint for the path corresponding to the 5591 * destination transport address to which the retransmission 5592 * is being sent (this may be different from the address for 5593 * which the timer expires [see Section 6.4]). Call this 5594 * value K. Bundle and retransmit those K DATA chunks in a 5595 * single packet to the destination endpoint. 5596 * 5597 * Note: Any DATA chunks that were sent to the address for 5598 * which the T3-rtx timer expired but did not fit in one MTU 5599 * (rule E3 above), should be marked for retransmission and 5600 * sent as soon as cwnd allows (normally when a SACK arrives). 5601 */ 5602 5603 /* Do some failure management (Section 8.2). */ 5604 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5605 5606 /* NB: Rules E4 and F1 are implicit in R1. */ 5607 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5608 5609 return SCTP_DISPOSITION_CONSUME; 5610 } 5611 5612 /* 5613 * Generate delayed SACK on timeout 5614 * 5615 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5616 * 5617 * The guidelines on delayed acknowledgement algorithm specified in 5618 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5619 * acknowledgement SHOULD be generated for at least every second packet 5620 * (not every second DATA chunk) received, and SHOULD be generated 5621 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5622 * some situations it may be beneficial for an SCTP transmitter to be 5623 * more conservative than the algorithms detailed in this document 5624 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5625 * the following algorithms allow. 5626 */ 5627 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5628 const struct sctp_endpoint *ep, 5629 const struct sctp_association *asoc, 5630 const union sctp_subtype type, 5631 void *arg, 5632 struct sctp_cmd_seq *commands) 5633 { 5634 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5635 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5636 return SCTP_DISPOSITION_CONSUME; 5637 } 5638 5639 /* 5640 * sctp_sf_t1_init_timer_expire 5641 * 5642 * Section: 4 Note: 2 5643 * Verification Tag: 5644 * Inputs 5645 * (endpoint, asoc) 5646 * 5647 * RFC 2960 Section 4 Notes 5648 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5649 * and re-start the T1-init timer without changing state. This MUST 5650 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5651 * endpoint MUST abort the initialization process and report the 5652 * error to SCTP user. 5653 * 5654 * Outputs 5655 * (timers, events) 5656 * 5657 */ 5658 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5659 struct net *net, 5660 const struct sctp_endpoint *ep, 5661 const struct sctp_association *asoc, 5662 const union sctp_subtype type, 5663 void *arg, 5664 struct sctp_cmd_seq *commands) 5665 { 5666 int attempts = asoc->init_err_counter + 1; 5667 struct sctp_chunk *repl = NULL; 5668 struct sctp_bind_addr *bp; 5669 5670 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5671 5672 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5673 5674 if (attempts <= asoc->max_init_attempts) { 5675 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5676 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5677 if (!repl) 5678 return SCTP_DISPOSITION_NOMEM; 5679 5680 /* Choose transport for INIT. */ 5681 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5682 SCTP_CHUNK(repl)); 5683 5684 /* Issue a sideeffect to do the needed accounting. */ 5685 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5686 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5687 5688 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5689 } else { 5690 pr_debug("%s: giving up on INIT, attempts:%d " 5691 "max_init_attempts:%d\n", __func__, attempts, 5692 asoc->max_init_attempts); 5693 5694 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5695 SCTP_ERROR(ETIMEDOUT)); 5696 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5697 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5698 return SCTP_DISPOSITION_DELETE_TCB; 5699 } 5700 5701 return SCTP_DISPOSITION_CONSUME; 5702 } 5703 5704 /* 5705 * sctp_sf_t1_cookie_timer_expire 5706 * 5707 * Section: 4 Note: 2 5708 * Verification Tag: 5709 * Inputs 5710 * (endpoint, asoc) 5711 * 5712 * RFC 2960 Section 4 Notes 5713 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5714 * COOKIE ECHO and re-start the T1-cookie timer without changing 5715 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5716 * After that, the endpoint MUST abort the initialization process and 5717 * report the error to SCTP user. 5718 * 5719 * Outputs 5720 * (timers, events) 5721 * 5722 */ 5723 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5724 struct net *net, 5725 const struct sctp_endpoint *ep, 5726 const struct sctp_association *asoc, 5727 const union sctp_subtype type, 5728 void *arg, 5729 struct sctp_cmd_seq *commands) 5730 { 5731 int attempts = asoc->init_err_counter + 1; 5732 struct sctp_chunk *repl = NULL; 5733 5734 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5735 5736 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5737 5738 if (attempts <= asoc->max_init_attempts) { 5739 repl = sctp_make_cookie_echo(asoc, NULL); 5740 if (!repl) 5741 return SCTP_DISPOSITION_NOMEM; 5742 5743 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5744 SCTP_CHUNK(repl)); 5745 /* Issue a sideeffect to do the needed accounting. */ 5746 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5747 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5748 5749 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5750 } else { 5751 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5752 SCTP_ERROR(ETIMEDOUT)); 5753 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5754 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5755 return SCTP_DISPOSITION_DELETE_TCB; 5756 } 5757 5758 return SCTP_DISPOSITION_CONSUME; 5759 } 5760 5761 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5762 * with the updated last sequential TSN received from its peer. 5763 * 5764 * An endpoint should limit the number of retransmissions of the 5765 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5766 * If this threshold is exceeded the endpoint should destroy the TCB and 5767 * MUST report the peer endpoint unreachable to the upper layer (and 5768 * thus the association enters the CLOSED state). The reception of any 5769 * packet from its peer (i.e. as the peer sends all of its queued DATA 5770 * chunks) should clear the endpoint's retransmission count and restart 5771 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5772 * all of its queued DATA chunks that have not yet been sent. 5773 */ 5774 enum sctp_disposition sctp_sf_t2_timer_expire( 5775 struct net *net, 5776 const struct sctp_endpoint *ep, 5777 const struct sctp_association *asoc, 5778 const union sctp_subtype type, 5779 void *arg, 5780 struct sctp_cmd_seq *commands) 5781 { 5782 struct sctp_chunk *reply = NULL; 5783 5784 pr_debug("%s: timer T2 expired\n", __func__); 5785 5786 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5787 5788 ((struct sctp_association *)asoc)->shutdown_retries++; 5789 5790 if (asoc->overall_error_count >= asoc->max_retrans) { 5791 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5792 SCTP_ERROR(ETIMEDOUT)); 5793 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5794 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5795 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5796 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5797 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5798 return SCTP_DISPOSITION_DELETE_TCB; 5799 } 5800 5801 switch (asoc->state) { 5802 case SCTP_STATE_SHUTDOWN_SENT: 5803 reply = sctp_make_shutdown(asoc, NULL); 5804 break; 5805 5806 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5807 reply = sctp_make_shutdown_ack(asoc, NULL); 5808 break; 5809 5810 default: 5811 BUG(); 5812 break; 5813 } 5814 5815 if (!reply) 5816 goto nomem; 5817 5818 /* Do some failure management (Section 8.2). 5819 * If we remove the transport an SHUTDOWN was last sent to, don't 5820 * do failure management. 5821 */ 5822 if (asoc->shutdown_last_sent_to) 5823 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5824 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5825 5826 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5827 * the T2-shutdown timer. 5828 */ 5829 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5830 5831 /* Restart the T2-shutdown timer. */ 5832 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5833 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5835 return SCTP_DISPOSITION_CONSUME; 5836 5837 nomem: 5838 return SCTP_DISPOSITION_NOMEM; 5839 } 5840 5841 /* 5842 * ADDIP Section 4.1 ASCONF CHunk Procedures 5843 * If the T4 RTO timer expires the endpoint should do B1 to B5 5844 */ 5845 enum sctp_disposition sctp_sf_t4_timer_expire( 5846 struct net *net, 5847 const struct sctp_endpoint *ep, 5848 const struct sctp_association *asoc, 5849 const union sctp_subtype type, 5850 void *arg, 5851 struct sctp_cmd_seq *commands) 5852 { 5853 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5854 struct sctp_transport *transport = chunk->transport; 5855 5856 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5857 5858 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5859 * detection on the appropriate destination address as defined in 5860 * RFC2960 [5] section 8.1 and 8.2. 5861 */ 5862 if (transport) 5863 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5864 SCTP_TRANSPORT(transport)); 5865 5866 /* Reconfig T4 timer and transport. */ 5867 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5868 5869 /* ADDIP 4.1 B2) Increment the association error counters and perform 5870 * endpoint failure detection on the association as defined in 5871 * RFC2960 [5] section 8.1 and 8.2. 5872 * association error counter is incremented in SCTP_CMD_STRIKE. 5873 */ 5874 if (asoc->overall_error_count >= asoc->max_retrans) { 5875 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5876 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5877 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5878 SCTP_ERROR(ETIMEDOUT)); 5879 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5880 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5881 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5882 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5883 return SCTP_DISPOSITION_ABORT; 5884 } 5885 5886 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5887 * the ASCONF chunk was sent by doubling the RTO timer value. 5888 * This is done in SCTP_CMD_STRIKE. 5889 */ 5890 5891 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5892 * choose an alternate destination address (please refer to RFC2960 5893 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5894 * chunk, it MUST be the same (including its serial number) as the last 5895 * ASCONF sent. 5896 */ 5897 sctp_chunk_hold(asoc->addip_last_asconf); 5898 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5899 SCTP_CHUNK(asoc->addip_last_asconf)); 5900 5901 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5902 * destination is selected, then the RTO used will be that of the new 5903 * destination address. 5904 */ 5905 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5906 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5907 5908 return SCTP_DISPOSITION_CONSUME; 5909 } 5910 5911 /* sctpimpguide-05 Section 2.12.2 5912 * The sender of the SHUTDOWN MAY also start an overall guard timer 5913 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5914 * At the expiration of this timer the sender SHOULD abort the association 5915 * by sending an ABORT chunk. 5916 */ 5917 enum sctp_disposition sctp_sf_t5_timer_expire( 5918 struct net *net, 5919 const struct sctp_endpoint *ep, 5920 const struct sctp_association *asoc, 5921 const union sctp_subtype type, 5922 void *arg, 5923 struct sctp_cmd_seq *commands) 5924 { 5925 struct sctp_chunk *reply = NULL; 5926 5927 pr_debug("%s: timer T5 expired\n", __func__); 5928 5929 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5930 5931 reply = sctp_make_abort(asoc, NULL, 0); 5932 if (!reply) 5933 goto nomem; 5934 5935 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5936 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5937 SCTP_ERROR(ETIMEDOUT)); 5938 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5939 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5940 5941 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5942 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5943 5944 return SCTP_DISPOSITION_DELETE_TCB; 5945 nomem: 5946 return SCTP_DISPOSITION_NOMEM; 5947 } 5948 5949 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5950 * the association is automatically closed by starting the shutdown process. 5951 * The work that needs to be done is same as when SHUTDOWN is initiated by 5952 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5953 */ 5954 enum sctp_disposition sctp_sf_autoclose_timer_expire( 5955 struct net *net, 5956 const struct sctp_endpoint *ep, 5957 const struct sctp_association *asoc, 5958 const union sctp_subtype type, 5959 void *arg, 5960 struct sctp_cmd_seq *commands) 5961 { 5962 enum sctp_disposition disposition; 5963 5964 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5965 5966 /* From 9.2 Shutdown of an Association 5967 * Upon receipt of the SHUTDOWN primitive from its upper 5968 * layer, the endpoint enters SHUTDOWN-PENDING state and 5969 * remains there until all outstanding data has been 5970 * acknowledged by its peer. The endpoint accepts no new data 5971 * from its upper layer, but retransmits data to the far end 5972 * if necessary to fill gaps. 5973 */ 5974 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5975 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5976 5977 disposition = SCTP_DISPOSITION_CONSUME; 5978 if (sctp_outq_is_empty(&asoc->outqueue)) { 5979 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5980 arg, commands); 5981 } 5982 5983 return disposition; 5984 } 5985 5986 /***************************************************************************** 5987 * These are sa state functions which could apply to all types of events. 5988 ****************************************************************************/ 5989 5990 /* 5991 * This table entry is not implemented. 5992 * 5993 * Inputs 5994 * (endpoint, asoc, chunk) 5995 * 5996 * The return value is the disposition of the chunk. 5997 */ 5998 enum sctp_disposition sctp_sf_not_impl(struct net *net, 5999 const struct sctp_endpoint *ep, 6000 const struct sctp_association *asoc, 6001 const union sctp_subtype type, 6002 void *arg, struct sctp_cmd_seq *commands) 6003 { 6004 return SCTP_DISPOSITION_NOT_IMPL; 6005 } 6006 6007 /* 6008 * This table entry represents a bug. 6009 * 6010 * Inputs 6011 * (endpoint, asoc, chunk) 6012 * 6013 * The return value is the disposition of the chunk. 6014 */ 6015 enum sctp_disposition sctp_sf_bug(struct net *net, 6016 const struct sctp_endpoint *ep, 6017 const struct sctp_association *asoc, 6018 const union sctp_subtype type, 6019 void *arg, struct sctp_cmd_seq *commands) 6020 { 6021 return SCTP_DISPOSITION_BUG; 6022 } 6023 6024 /* 6025 * This table entry represents the firing of a timer in the wrong state. 6026 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6027 * when the association is in the wrong state. This event should 6028 * be ignored, so as to prevent any rearming of the timer. 6029 * 6030 * Inputs 6031 * (endpoint, asoc, chunk) 6032 * 6033 * The return value is the disposition of the chunk. 6034 */ 6035 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6036 const struct sctp_endpoint *ep, 6037 const struct sctp_association *asoc, 6038 const union sctp_subtype type, 6039 void *arg, 6040 struct sctp_cmd_seq *commands) 6041 { 6042 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6043 6044 return SCTP_DISPOSITION_CONSUME; 6045 } 6046 6047 /******************************************************************** 6048 * 2nd Level Abstractions 6049 ********************************************************************/ 6050 6051 /* Pull the SACK chunk based on the SACK header. */ 6052 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6053 { 6054 struct sctp_sackhdr *sack; 6055 __u16 num_dup_tsns; 6056 unsigned int len; 6057 __u16 num_blocks; 6058 6059 /* Protect ourselves from reading too far into 6060 * the skb from a bogus sender. 6061 */ 6062 sack = (struct sctp_sackhdr *) chunk->skb->data; 6063 6064 num_blocks = ntohs(sack->num_gap_ack_blocks); 6065 num_dup_tsns = ntohs(sack->num_dup_tsns); 6066 len = sizeof(struct sctp_sackhdr); 6067 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6068 if (len > chunk->skb->len) 6069 return NULL; 6070 6071 skb_pull(chunk->skb, len); 6072 6073 return sack; 6074 } 6075 6076 /* Create an ABORT packet to be sent as a response, with the specified 6077 * error causes. 6078 */ 6079 static struct sctp_packet *sctp_abort_pkt_new( 6080 struct net *net, 6081 const struct sctp_endpoint *ep, 6082 const struct sctp_association *asoc, 6083 struct sctp_chunk *chunk, 6084 const void *payload, size_t paylen) 6085 { 6086 struct sctp_packet *packet; 6087 struct sctp_chunk *abort; 6088 6089 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6090 6091 if (packet) { 6092 /* Make an ABORT. 6093 * The T bit will be set if the asoc is NULL. 6094 */ 6095 abort = sctp_make_abort(asoc, chunk, paylen); 6096 if (!abort) { 6097 sctp_ootb_pkt_free(packet); 6098 return NULL; 6099 } 6100 6101 /* Reflect vtag if T-Bit is set */ 6102 if (sctp_test_T_bit(abort)) 6103 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6104 6105 /* Add specified error causes, i.e., payload, to the 6106 * end of the chunk. 6107 */ 6108 sctp_addto_chunk(abort, paylen, payload); 6109 6110 /* Set the skb to the belonging sock for accounting. */ 6111 abort->skb->sk = ep->base.sk; 6112 6113 sctp_packet_append_chunk(packet, abort); 6114 6115 } 6116 6117 return packet; 6118 } 6119 6120 /* Allocate a packet for responding in the OOTB conditions. */ 6121 static struct sctp_packet *sctp_ootb_pkt_new( 6122 struct net *net, 6123 const struct sctp_association *asoc, 6124 const struct sctp_chunk *chunk) 6125 { 6126 struct sctp_transport *transport; 6127 struct sctp_packet *packet; 6128 __u16 sport, dport; 6129 __u32 vtag; 6130 6131 /* Get the source and destination port from the inbound packet. */ 6132 sport = ntohs(chunk->sctp_hdr->dest); 6133 dport = ntohs(chunk->sctp_hdr->source); 6134 6135 /* The V-tag is going to be the same as the inbound packet if no 6136 * association exists, otherwise, use the peer's vtag. 6137 */ 6138 if (asoc) { 6139 /* Special case the INIT-ACK as there is no peer's vtag 6140 * yet. 6141 */ 6142 switch (chunk->chunk_hdr->type) { 6143 case SCTP_CID_INIT_ACK: 6144 { 6145 struct sctp_initack_chunk *initack; 6146 6147 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6148 vtag = ntohl(initack->init_hdr.init_tag); 6149 break; 6150 } 6151 default: 6152 vtag = asoc->peer.i.init_tag; 6153 break; 6154 } 6155 } else { 6156 /* Special case the INIT and stale COOKIE_ECHO as there is no 6157 * vtag yet. 6158 */ 6159 switch (chunk->chunk_hdr->type) { 6160 case SCTP_CID_INIT: 6161 { 6162 struct sctp_init_chunk *init; 6163 6164 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6165 vtag = ntohl(init->init_hdr.init_tag); 6166 break; 6167 } 6168 default: 6169 vtag = ntohl(chunk->sctp_hdr->vtag); 6170 break; 6171 } 6172 } 6173 6174 /* Make a transport for the bucket, Eliza... */ 6175 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6176 if (!transport) 6177 goto nomem; 6178 6179 /* Cache a route for the transport with the chunk's destination as 6180 * the source address. 6181 */ 6182 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6183 sctp_sk(net->sctp.ctl_sock)); 6184 6185 packet = &transport->packet; 6186 sctp_packet_init(packet, transport, sport, dport); 6187 sctp_packet_config(packet, vtag, 0); 6188 6189 return packet; 6190 6191 nomem: 6192 return NULL; 6193 } 6194 6195 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6196 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6197 { 6198 sctp_transport_free(packet->transport); 6199 } 6200 6201 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6202 static void sctp_send_stale_cookie_err(struct net *net, 6203 const struct sctp_endpoint *ep, 6204 const struct sctp_association *asoc, 6205 const struct sctp_chunk *chunk, 6206 struct sctp_cmd_seq *commands, 6207 struct sctp_chunk *err_chunk) 6208 { 6209 struct sctp_packet *packet; 6210 6211 if (err_chunk) { 6212 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6213 if (packet) { 6214 struct sctp_signed_cookie *cookie; 6215 6216 /* Override the OOTB vtag from the cookie. */ 6217 cookie = chunk->subh.cookie_hdr; 6218 packet->vtag = cookie->c.peer_vtag; 6219 6220 /* Set the skb to the belonging sock for accounting. */ 6221 err_chunk->skb->sk = ep->base.sk; 6222 sctp_packet_append_chunk(packet, err_chunk); 6223 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6224 SCTP_PACKET(packet)); 6225 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6226 } else 6227 sctp_chunk_free (err_chunk); 6228 } 6229 } 6230 6231 6232 /* Process a data chunk */ 6233 static int sctp_eat_data(const struct sctp_association *asoc, 6234 struct sctp_chunk *chunk, 6235 struct sctp_cmd_seq *commands) 6236 { 6237 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6238 struct sock *sk = asoc->base.sk; 6239 struct net *net = sock_net(sk); 6240 struct sctp_datahdr *data_hdr; 6241 struct sctp_chunk *err; 6242 enum sctp_verb deliver; 6243 size_t datalen; 6244 __u32 tsn; 6245 int tmp; 6246 6247 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6248 chunk->subh.data_hdr = data_hdr; 6249 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6250 6251 tsn = ntohl(data_hdr->tsn); 6252 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6253 6254 /* ASSERT: Now skb->data is really the user data. */ 6255 6256 /* Process ECN based congestion. 6257 * 6258 * Since the chunk structure is reused for all chunks within 6259 * a packet, we use ecn_ce_done to track if we've already 6260 * done CE processing for this packet. 6261 * 6262 * We need to do ECN processing even if we plan to discard the 6263 * chunk later. 6264 */ 6265 6266 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6267 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6268 chunk->ecn_ce_done = 1; 6269 6270 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6271 /* Do real work as sideffect. */ 6272 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6273 SCTP_U32(tsn)); 6274 } 6275 } 6276 6277 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6278 if (tmp < 0) { 6279 /* The TSN is too high--silently discard the chunk and 6280 * count on it getting retransmitted later. 6281 */ 6282 if (chunk->asoc) 6283 chunk->asoc->stats.outofseqtsns++; 6284 return SCTP_IERROR_HIGH_TSN; 6285 } else if (tmp > 0) { 6286 /* This is a duplicate. Record it. */ 6287 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6288 return SCTP_IERROR_DUP_TSN; 6289 } 6290 6291 /* This is a new TSN. */ 6292 6293 /* Discard if there is no room in the receive window. 6294 * Actually, allow a little bit of overflow (up to a MTU). 6295 */ 6296 datalen = ntohs(chunk->chunk_hdr->length); 6297 datalen -= sctp_datachk_len(&asoc->stream); 6298 6299 deliver = SCTP_CMD_CHUNK_ULP; 6300 6301 /* Think about partial delivery. */ 6302 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6303 6304 /* Even if we don't accept this chunk there is 6305 * memory pressure. 6306 */ 6307 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6308 } 6309 6310 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6311 * seems a bit troublesome in that frag_point varies based on 6312 * PMTU. In cases, such as loopback, this might be a rather 6313 * large spill over. 6314 */ 6315 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6316 (datalen > asoc->rwnd + asoc->frag_point))) { 6317 6318 /* If this is the next TSN, consider reneging to make 6319 * room. Note: Playing nice with a confused sender. A 6320 * malicious sender can still eat up all our buffer 6321 * space and in the future we may want to detect and 6322 * do more drastic reneging. 6323 */ 6324 if (sctp_tsnmap_has_gap(map) && 6325 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6326 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6327 deliver = SCTP_CMD_RENEGE; 6328 } else { 6329 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6330 __func__, tsn, datalen, asoc->rwnd); 6331 6332 return SCTP_IERROR_IGNORE_TSN; 6333 } 6334 } 6335 6336 /* 6337 * Also try to renege to limit our memory usage in the event that 6338 * we are under memory pressure 6339 * If we can't renege, don't worry about it, the sk_rmem_schedule 6340 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6341 * memory usage too much 6342 */ 6343 if (*sk->sk_prot_creator->memory_pressure) { 6344 if (sctp_tsnmap_has_gap(map) && 6345 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6346 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6347 __func__, tsn); 6348 deliver = SCTP_CMD_RENEGE; 6349 } 6350 } 6351 6352 /* 6353 * Section 3.3.10.9 No User Data (9) 6354 * 6355 * Cause of error 6356 * --------------- 6357 * No User Data: This error cause is returned to the originator of a 6358 * DATA chunk if a received DATA chunk has no user data. 6359 */ 6360 if (unlikely(0 == datalen)) { 6361 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6362 if (err) { 6363 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6364 SCTP_CHUNK(err)); 6365 } 6366 /* We are going to ABORT, so we might as well stop 6367 * processing the rest of the chunks in the packet. 6368 */ 6369 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6370 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6371 SCTP_ERROR(ECONNABORTED)); 6372 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6373 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6374 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6375 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6376 return SCTP_IERROR_NO_DATA; 6377 } 6378 6379 chunk->data_accepted = 1; 6380 6381 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6382 * if we renege and the chunk arrives again. 6383 */ 6384 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6385 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6386 if (chunk->asoc) 6387 chunk->asoc->stats.iuodchunks++; 6388 } else { 6389 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6390 if (chunk->asoc) 6391 chunk->asoc->stats.iodchunks++; 6392 } 6393 6394 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6395 * 6396 * If an endpoint receive a DATA chunk with an invalid stream 6397 * identifier, it shall acknowledge the reception of the DATA chunk 6398 * following the normal procedure, immediately send an ERROR chunk 6399 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6400 * and discard the DATA chunk. 6401 */ 6402 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6403 /* Mark tsn as received even though we drop it */ 6404 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6405 6406 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6407 &data_hdr->stream, 6408 sizeof(data_hdr->stream), 6409 sizeof(u16)); 6410 if (err) 6411 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6412 SCTP_CHUNK(err)); 6413 return SCTP_IERROR_BAD_STREAM; 6414 } 6415 6416 /* Check to see if the SSN is possible for this TSN. 6417 * The biggest gap we can record is 4K wide. Since SSNs wrap 6418 * at an unsigned short, there is no way that an SSN can 6419 * wrap and for a valid TSN. We can simply check if the current 6420 * SSN is smaller then the next expected one. If it is, it wrapped 6421 * and is invalid. 6422 */ 6423 if (!asoc->stream.si->validate_data(chunk)) 6424 return SCTP_IERROR_PROTO_VIOLATION; 6425 6426 /* Send the data up to the user. Note: Schedule the 6427 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6428 * chunk needs the updated rwnd. 6429 */ 6430 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6431 6432 return SCTP_IERROR_NO_ERROR; 6433 } 6434