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 /* Update socket peer label if first association. */ 325 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 326 chunk->skb)) 327 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 328 329 /* 6.10 Bundling 330 * An endpoint MUST NOT bundle INIT, INIT ACK or 331 * SHUTDOWN COMPLETE with any other chunks. 332 * 333 * IG Section 2.11.2 334 * Furthermore, we require that the receiver of an INIT chunk MUST 335 * enforce these rules by silently discarding an arriving packet 336 * with an INIT chunk that is bundled with other chunks. 337 */ 338 if (!chunk->singleton) 339 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 340 341 /* If the packet is an OOTB packet which is temporarily on the 342 * control endpoint, respond with an ABORT. 343 */ 344 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 345 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 346 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 347 } 348 349 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 350 * Tag. 351 */ 352 if (chunk->sctp_hdr->vtag != 0) 353 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 354 355 /* Make sure that the INIT chunk has a valid length. 356 * Normally, this would cause an ABORT with a Protocol Violation 357 * error, but since we don't have an association, we'll 358 * just discard the packet. 359 */ 360 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 361 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 362 363 /* If the INIT is coming toward a closing socket, we'll send back 364 * and ABORT. Essentially, this catches the race of INIT being 365 * backloged to the socket at the same time as the user isses close(). 366 * Since the socket and all its associations are going away, we 367 * can treat this OOTB 368 */ 369 if (sctp_sstate(ep->base.sk, CLOSING)) 370 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 371 372 /* Verify the INIT chunk before processing it. */ 373 err_chunk = NULL; 374 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 375 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 376 &err_chunk)) { 377 /* This chunk contains fatal error. It is to be discarded. 378 * Send an ABORT, with causes if there is any. 379 */ 380 if (err_chunk) { 381 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 382 (__u8 *)(err_chunk->chunk_hdr) + 383 sizeof(struct sctp_chunkhdr), 384 ntohs(err_chunk->chunk_hdr->length) - 385 sizeof(struct sctp_chunkhdr)); 386 387 sctp_chunk_free(err_chunk); 388 389 if (packet) { 390 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 391 SCTP_PACKET(packet)); 392 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 393 return SCTP_DISPOSITION_CONSUME; 394 } else { 395 return SCTP_DISPOSITION_NOMEM; 396 } 397 } else { 398 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 399 commands); 400 } 401 } 402 403 /* Grab the INIT header. */ 404 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 405 406 /* Tag the variable length parameters. */ 407 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 408 409 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 410 if (!new_asoc) 411 goto nomem; 412 413 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 414 sctp_scope(sctp_source(chunk)), 415 GFP_ATOMIC) < 0) 416 goto nomem_init; 417 418 /* The call, sctp_process_init(), can fail on memory allocation. */ 419 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 420 (struct sctp_init_chunk *)chunk->chunk_hdr, 421 GFP_ATOMIC)) 422 goto nomem_init; 423 424 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 425 426 /* If there are errors need to be reported for unknown parameters, 427 * make sure to reserve enough room in the INIT ACK for them. 428 */ 429 len = 0; 430 if (err_chunk) 431 len = ntohs(err_chunk->chunk_hdr->length) - 432 sizeof(struct sctp_chunkhdr); 433 434 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 435 if (!repl) 436 goto nomem_init; 437 438 /* If there are errors need to be reported for unknown parameters, 439 * include them in the outgoing INIT ACK as "Unrecognized parameter" 440 * parameter. 441 */ 442 if (err_chunk) { 443 /* Get the "Unrecognized parameter" parameter(s) out of the 444 * ERROR chunk generated by sctp_verify_init(). Since the 445 * error cause code for "unknown parameter" and the 446 * "Unrecognized parameter" type is the same, we can 447 * construct the parameters in INIT ACK by copying the 448 * ERROR causes over. 449 */ 450 unk_param = (struct sctp_unrecognized_param *) 451 ((__u8 *)(err_chunk->chunk_hdr) + 452 sizeof(struct sctp_chunkhdr)); 453 /* Replace the cause code with the "Unrecognized parameter" 454 * parameter type. 455 */ 456 sctp_addto_chunk(repl, len, unk_param); 457 sctp_chunk_free(err_chunk); 458 } 459 460 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 461 462 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 463 464 /* 465 * Note: After sending out INIT ACK with the State Cookie parameter, 466 * "Z" MUST NOT allocate any resources, nor keep any states for the 467 * new association. Otherwise, "Z" will be vulnerable to resource 468 * attacks. 469 */ 470 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 471 472 return SCTP_DISPOSITION_DELETE_TCB; 473 474 nomem_init: 475 sctp_association_free(new_asoc); 476 nomem: 477 if (err_chunk) 478 sctp_chunk_free(err_chunk); 479 return SCTP_DISPOSITION_NOMEM; 480 } 481 482 /* 483 * Respond to a normal INIT ACK chunk. 484 * We are the side that is initiating the association. 485 * 486 * Section: 5.1 Normal Establishment of an Association, C 487 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 488 * timer and leave COOKIE-WAIT state. "A" shall then send the State 489 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 490 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 491 * 492 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 493 * DATA chunks, but it MUST be the first chunk in the packet and 494 * until the COOKIE ACK is returned the sender MUST NOT send any 495 * other packets to the peer. 496 * 497 * Verification Tag: 3.3.3 498 * If the value of the Initiate Tag in a received INIT ACK chunk is 499 * found to be 0, the receiver MUST treat it as an error and close the 500 * association by transmitting an ABORT. 501 * 502 * Inputs 503 * (endpoint, asoc, chunk) 504 * 505 * Outputs 506 * (asoc, reply_msg, msg_up, timers, counters) 507 * 508 * The return value is the disposition of the chunk. 509 */ 510 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 511 const struct sctp_endpoint *ep, 512 const struct sctp_association *asoc, 513 const union sctp_subtype type, 514 void *arg, 515 struct sctp_cmd_seq *commands) 516 { 517 struct sctp_init_chunk *initchunk; 518 struct sctp_chunk *chunk = arg; 519 struct sctp_chunk *err_chunk; 520 struct sctp_packet *packet; 521 522 if (!sctp_vtag_verify(chunk, asoc)) 523 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 524 525 /* 6.10 Bundling 526 * An endpoint MUST NOT bundle INIT, INIT ACK or 527 * SHUTDOWN COMPLETE with any other chunks. 528 */ 529 if (!chunk->singleton) 530 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 531 532 /* Make sure that the INIT-ACK chunk has a valid length */ 533 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 534 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 535 commands); 536 /* Grab the INIT header. */ 537 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 538 539 /* Verify the INIT chunk before processing it. */ 540 err_chunk = NULL; 541 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 542 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 543 &err_chunk)) { 544 545 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 546 547 /* This chunk contains fatal error. It is to be discarded. 548 * Send an ABORT, with causes. If there are no causes, 549 * then there wasn't enough memory. Just terminate 550 * the association. 551 */ 552 if (err_chunk) { 553 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 554 (__u8 *)(err_chunk->chunk_hdr) + 555 sizeof(struct sctp_chunkhdr), 556 ntohs(err_chunk->chunk_hdr->length) - 557 sizeof(struct sctp_chunkhdr)); 558 559 sctp_chunk_free(err_chunk); 560 561 if (packet) { 562 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 563 SCTP_PACKET(packet)); 564 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 565 error = SCTP_ERROR_INV_PARAM; 566 } 567 } 568 569 /* SCTP-AUTH, Section 6.3: 570 * It should be noted that if the receiver wants to tear 571 * down an association in an authenticated way only, the 572 * handling of malformed packets should not result in 573 * tearing down the association. 574 * 575 * This means that if we only want to abort associations 576 * in an authenticated way (i.e AUTH+ABORT), then we 577 * can't destroy this association just because the packet 578 * was malformed. 579 */ 580 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 581 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 582 583 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 584 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 585 asoc, chunk->transport); 586 } 587 588 /* Tag the variable length parameters. Note that we never 589 * convert the parameters in an INIT chunk. 590 */ 591 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 592 593 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 594 595 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 596 SCTP_PEER_INIT(initchunk)); 597 598 /* Reset init error count upon receipt of INIT-ACK. */ 599 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 600 601 /* 5.1 C) "A" shall stop the T1-init timer and leave 602 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 603 * timer, and enter the COOKIE-ECHOED state. 604 */ 605 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 606 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 607 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 608 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 609 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 610 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 611 612 /* SCTP-AUTH: genereate the assocition shared keys so that 613 * we can potentially signe the COOKIE-ECHO. 614 */ 615 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 616 617 /* 5.1 C) "A" shall then send the State Cookie received in the 618 * INIT ACK chunk in a COOKIE ECHO chunk, ... 619 */ 620 /* If there is any errors to report, send the ERROR chunk generated 621 * for unknown parameters as well. 622 */ 623 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 624 SCTP_CHUNK(err_chunk)); 625 626 return SCTP_DISPOSITION_CONSUME; 627 } 628 629 /* 630 * Respond to a normal COOKIE ECHO chunk. 631 * We are the side that is being asked for an association. 632 * 633 * Section: 5.1 Normal Establishment of an Association, D 634 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 635 * with a COOKIE ACK chunk after building a TCB and moving to 636 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 637 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 638 * chunk MUST be the first chunk in the packet. 639 * 640 * IMPLEMENTATION NOTE: An implementation may choose to send the 641 * Communication Up notification to the SCTP user upon reception 642 * of a valid COOKIE ECHO chunk. 643 * 644 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 645 * D) Rules for packet carrying a COOKIE ECHO 646 * 647 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 648 * Initial Tag received in the INIT ACK. 649 * 650 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 651 * 652 * Inputs 653 * (endpoint, asoc, chunk) 654 * 655 * Outputs 656 * (asoc, reply_msg, msg_up, timers, counters) 657 * 658 * The return value is the disposition of the chunk. 659 */ 660 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 661 const struct sctp_endpoint *ep, 662 const struct sctp_association *asoc, 663 const union sctp_subtype type, 664 void *arg, 665 struct sctp_cmd_seq *commands) 666 { 667 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 668 struct sctp_association *new_asoc; 669 struct sctp_init_chunk *peer_init; 670 struct sctp_chunk *chunk = arg; 671 struct sctp_chunk *err_chk_p; 672 struct sctp_chunk *repl; 673 struct sock *sk; 674 int error = 0; 675 676 /* If the packet is an OOTB packet which is temporarily on the 677 * control endpoint, respond with an ABORT. 678 */ 679 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 680 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 681 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 682 } 683 684 /* Make sure that the COOKIE_ECHO chunk has a valid length. 685 * In this case, we check that we have enough for at least a 686 * chunk header. More detailed verification is done 687 * in sctp_unpack_cookie(). 688 */ 689 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 690 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 691 692 /* If the endpoint is not listening or if the number of associations 693 * on the TCP-style socket exceed the max backlog, respond with an 694 * ABORT. 695 */ 696 sk = ep->base.sk; 697 if (!sctp_sstate(sk, LISTENING) || 698 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 699 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 700 701 /* "Decode" the chunk. We have no optional parameters so we 702 * are in good shape. 703 */ 704 chunk->subh.cookie_hdr = 705 (struct sctp_signed_cookie *)chunk->skb->data; 706 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 707 sizeof(struct sctp_chunkhdr))) 708 goto nomem; 709 710 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 711 * "Z" will reply with a COOKIE ACK chunk after building a TCB 712 * and moving to the ESTABLISHED state. 713 */ 714 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 715 &err_chk_p); 716 717 /* FIXME: 718 * If the re-build failed, what is the proper error path 719 * from here? 720 * 721 * [We should abort the association. --piggy] 722 */ 723 if (!new_asoc) { 724 /* FIXME: Several errors are possible. A bad cookie should 725 * be silently discarded, but think about logging it too. 726 */ 727 switch (error) { 728 case -SCTP_IERROR_NOMEM: 729 goto nomem; 730 731 case -SCTP_IERROR_STALE_COOKIE: 732 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 733 err_chk_p); 734 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 735 736 case -SCTP_IERROR_BAD_SIG: 737 default: 738 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 739 } 740 } 741 742 743 /* Delay state machine commands until later. 744 * 745 * Re-build the bind address for the association is done in 746 * the sctp_unpack_cookie() already. 747 */ 748 /* This is a brand-new association, so these are not yet side 749 * effects--it is safe to run them here. 750 */ 751 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 752 753 if (!sctp_process_init(new_asoc, chunk, 754 &chunk->subh.cookie_hdr->c.peer_addr, 755 peer_init, GFP_ATOMIC)) 756 goto nomem_init; 757 758 /* SCTP-AUTH: Now that we've populate required fields in 759 * sctp_process_init, set up the assocaition shared keys as 760 * necessary so that we can potentially authenticate the ACK 761 */ 762 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 763 if (error) 764 goto nomem_init; 765 766 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 767 * is supposed to be authenticated and we have to do delayed 768 * authentication. We've just recreated the association using 769 * the information in the cookie and now it's much easier to 770 * do the authentication. 771 */ 772 if (chunk->auth_chunk) { 773 struct sctp_chunk auth; 774 enum sctp_ierror ret; 775 776 /* Make sure that we and the peer are AUTH capable */ 777 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) { 778 sctp_association_free(new_asoc); 779 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 780 } 781 782 /* set-up our fake chunk so that we can process it */ 783 auth.skb = chunk->auth_chunk; 784 auth.asoc = chunk->asoc; 785 auth.sctp_hdr = chunk->sctp_hdr; 786 auth.chunk_hdr = (struct sctp_chunkhdr *) 787 skb_push(chunk->auth_chunk, 788 sizeof(struct sctp_chunkhdr)); 789 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 790 auth.transport = chunk->transport; 791 792 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 793 if (ret != SCTP_IERROR_NO_ERROR) { 794 sctp_association_free(new_asoc); 795 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 796 } 797 } 798 799 repl = sctp_make_cookie_ack(new_asoc, chunk); 800 if (!repl) 801 goto nomem_init; 802 803 /* RFC 2960 5.1 Normal Establishment of an Association 804 * 805 * D) IMPLEMENTATION NOTE: An implementation may choose to 806 * send the Communication Up notification to the SCTP user 807 * upon reception of a valid COOKIE ECHO chunk. 808 */ 809 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 810 new_asoc->c.sinit_num_ostreams, 811 new_asoc->c.sinit_max_instreams, 812 NULL, GFP_ATOMIC); 813 if (!ev) 814 goto nomem_ev; 815 816 /* Sockets API Draft Section 5.3.1.6 817 * When a peer sends a Adaptation Layer Indication parameter , SCTP 818 * delivers this notification to inform the application that of the 819 * peers requested adaptation layer. 820 */ 821 if (new_asoc->peer.adaptation_ind) { 822 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 823 GFP_ATOMIC); 824 if (!ai_ev) 825 goto nomem_aiev; 826 } 827 828 if (!new_asoc->peer.auth_capable) { 829 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 830 SCTP_AUTH_NO_AUTH, 831 GFP_ATOMIC); 832 if (!auth_ev) 833 goto nomem_authev; 834 } 835 836 /* Add all the state machine commands now since we've created 837 * everything. This way we don't introduce memory corruptions 838 * during side-effect processing and correclty count established 839 * associations. 840 */ 841 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 842 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 843 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 844 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 845 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 846 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 847 848 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 849 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 850 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 851 852 /* This will send the COOKIE ACK */ 853 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 854 855 /* Queue the ASSOC_CHANGE event */ 856 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 857 858 /* Send up the Adaptation Layer Indication event */ 859 if (ai_ev) 860 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 861 SCTP_ULPEVENT(ai_ev)); 862 863 if (auth_ev) 864 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 865 SCTP_ULPEVENT(auth_ev)); 866 867 return SCTP_DISPOSITION_CONSUME; 868 869 nomem_authev: 870 sctp_ulpevent_free(ai_ev); 871 nomem_aiev: 872 sctp_ulpevent_free(ev); 873 nomem_ev: 874 sctp_chunk_free(repl); 875 nomem_init: 876 sctp_association_free(new_asoc); 877 nomem: 878 return SCTP_DISPOSITION_NOMEM; 879 } 880 881 /* 882 * Respond to a normal COOKIE ACK chunk. 883 * We are the side that is asking for an association. 884 * 885 * RFC 2960 5.1 Normal Establishment of an Association 886 * 887 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 888 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 889 * timer. It may also notify its ULP about the successful 890 * establishment of the association with a Communication Up 891 * notification (see Section 10). 892 * 893 * Verification Tag: 894 * Inputs 895 * (endpoint, asoc, chunk) 896 * 897 * Outputs 898 * (asoc, reply_msg, msg_up, timers, counters) 899 * 900 * The return value is the disposition of the chunk. 901 */ 902 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 903 const struct sctp_endpoint *ep, 904 const struct sctp_association *asoc, 905 const union sctp_subtype type, 906 void *arg, 907 struct sctp_cmd_seq *commands) 908 { 909 struct sctp_chunk *chunk = arg; 910 struct sctp_ulpevent *ev; 911 912 if (!sctp_vtag_verify(chunk, asoc)) 913 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 914 915 /* Verify that the chunk length for the COOKIE-ACK is OK. 916 * If we don't do this, any bundled chunks may be junked. 917 */ 918 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 919 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 920 commands); 921 922 /* Reset init error count upon receipt of COOKIE-ACK, 923 * to avoid problems with the managemement of this 924 * counter in stale cookie situations when a transition back 925 * from the COOKIE-ECHOED state to the COOKIE-WAIT 926 * state is performed. 927 */ 928 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 929 930 /* Set peer label for connection. */ 931 security_inet_conn_established(ep->base.sk, chunk->skb); 932 933 /* RFC 2960 5.1 Normal Establishment of an Association 934 * 935 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 936 * from the COOKIE-ECHOED state to the ESTABLISHED state, 937 * stopping the T1-cookie timer. 938 */ 939 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 940 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 941 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 942 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 943 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 944 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 945 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 946 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 947 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 948 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 949 950 /* It may also notify its ULP about the successful 951 * establishment of the association with a Communication Up 952 * notification (see Section 10). 953 */ 954 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 955 0, asoc->c.sinit_num_ostreams, 956 asoc->c.sinit_max_instreams, 957 NULL, GFP_ATOMIC); 958 959 if (!ev) 960 goto nomem; 961 962 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 963 964 /* Sockets API Draft Section 5.3.1.6 965 * When a peer sends a Adaptation Layer Indication parameter , SCTP 966 * delivers this notification to inform the application that of the 967 * peers requested adaptation layer. 968 */ 969 if (asoc->peer.adaptation_ind) { 970 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 971 if (!ev) 972 goto nomem; 973 974 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 975 SCTP_ULPEVENT(ev)); 976 } 977 978 if (!asoc->peer.auth_capable) { 979 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 980 GFP_ATOMIC); 981 if (!ev) 982 goto nomem; 983 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 984 SCTP_ULPEVENT(ev)); 985 } 986 987 return SCTP_DISPOSITION_CONSUME; 988 nomem: 989 return SCTP_DISPOSITION_NOMEM; 990 } 991 992 /* Generate and sendout a heartbeat packet. */ 993 static enum sctp_disposition sctp_sf_heartbeat( 994 const struct sctp_endpoint *ep, 995 const struct sctp_association *asoc, 996 const union sctp_subtype type, 997 void *arg, 998 struct sctp_cmd_seq *commands) 999 { 1000 struct sctp_transport *transport = (struct sctp_transport *) arg; 1001 struct sctp_chunk *reply; 1002 1003 /* Send a heartbeat to our peer. */ 1004 reply = sctp_make_heartbeat(asoc, transport); 1005 if (!reply) 1006 return SCTP_DISPOSITION_NOMEM; 1007 1008 /* Set rto_pending indicating that an RTT measurement 1009 * is started with this heartbeat chunk. 1010 */ 1011 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1012 SCTP_TRANSPORT(transport)); 1013 1014 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1015 return SCTP_DISPOSITION_CONSUME; 1016 } 1017 1018 /* Generate a HEARTBEAT packet on the given transport. */ 1019 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1020 const struct sctp_endpoint *ep, 1021 const struct sctp_association *asoc, 1022 const union sctp_subtype type, 1023 void *arg, 1024 struct sctp_cmd_seq *commands) 1025 { 1026 struct sctp_transport *transport = (struct sctp_transport *) arg; 1027 1028 if (asoc->overall_error_count >= asoc->max_retrans) { 1029 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1030 SCTP_ERROR(ETIMEDOUT)); 1031 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1032 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1033 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1034 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1035 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1036 return SCTP_DISPOSITION_DELETE_TCB; 1037 } 1038 1039 /* Section 3.3.5. 1040 * The Sender-specific Heartbeat Info field should normally include 1041 * information about the sender's current time when this HEARTBEAT 1042 * chunk is sent and the destination transport address to which this 1043 * HEARTBEAT is sent (see Section 8.3). 1044 */ 1045 1046 if (transport->param_flags & SPP_HB_ENABLE) { 1047 if (SCTP_DISPOSITION_NOMEM == 1048 sctp_sf_heartbeat(ep, asoc, type, arg, 1049 commands)) 1050 return SCTP_DISPOSITION_NOMEM; 1051 1052 /* Set transport error counter and association error counter 1053 * when sending heartbeat. 1054 */ 1055 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1056 SCTP_TRANSPORT(transport)); 1057 } 1058 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1059 SCTP_TRANSPORT(transport)); 1060 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1061 SCTP_TRANSPORT(transport)); 1062 1063 return SCTP_DISPOSITION_CONSUME; 1064 } 1065 1066 /* resend asoc strreset_chunk. */ 1067 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1068 const struct sctp_endpoint *ep, 1069 const struct sctp_association *asoc, 1070 const union sctp_subtype type, 1071 void *arg, 1072 struct sctp_cmd_seq *commands) 1073 { 1074 struct sctp_transport *transport = arg; 1075 1076 if (asoc->overall_error_count >= asoc->max_retrans) { 1077 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1078 SCTP_ERROR(ETIMEDOUT)); 1079 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1080 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1081 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1082 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1083 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1084 return SCTP_DISPOSITION_DELETE_TCB; 1085 } 1086 1087 sctp_chunk_hold(asoc->strreset_chunk); 1088 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1089 SCTP_CHUNK(asoc->strreset_chunk)); 1090 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1091 1092 return SCTP_DISPOSITION_CONSUME; 1093 } 1094 1095 /* 1096 * Process an heartbeat request. 1097 * 1098 * Section: 8.3 Path Heartbeat 1099 * The receiver of the HEARTBEAT should immediately respond with a 1100 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1101 * from the received HEARTBEAT chunk. 1102 * 1103 * Verification Tag: 8.5 Verification Tag [Normal verification] 1104 * When receiving an SCTP packet, the endpoint MUST ensure that the 1105 * value in the Verification Tag field of the received SCTP packet 1106 * matches its own Tag. If the received Verification Tag value does not 1107 * match the receiver's own tag value, the receiver shall silently 1108 * discard the packet and shall not process it any further except for 1109 * those cases listed in Section 8.5.1 below. 1110 * 1111 * Inputs 1112 * (endpoint, asoc, chunk) 1113 * 1114 * Outputs 1115 * (asoc, reply_msg, msg_up, timers, counters) 1116 * 1117 * The return value is the disposition of the chunk. 1118 */ 1119 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1120 const struct sctp_endpoint *ep, 1121 const struct sctp_association *asoc, 1122 const union sctp_subtype type, 1123 void *arg, struct sctp_cmd_seq *commands) 1124 { 1125 struct sctp_paramhdr *param_hdr; 1126 struct sctp_chunk *chunk = arg; 1127 struct sctp_chunk *reply; 1128 size_t paylen = 0; 1129 1130 if (!sctp_vtag_verify(chunk, asoc)) 1131 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1132 1133 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1134 if (!sctp_chunk_length_valid(chunk, 1135 sizeof(struct sctp_heartbeat_chunk))) 1136 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1137 commands); 1138 1139 /* 8.3 The receiver of the HEARTBEAT should immediately 1140 * respond with a HEARTBEAT ACK that contains the Heartbeat 1141 * Information field copied from the received HEARTBEAT chunk. 1142 */ 1143 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1144 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1145 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1146 1147 if (ntohs(param_hdr->length) > paylen) 1148 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1149 param_hdr, commands); 1150 1151 if (!pskb_pull(chunk->skb, paylen)) 1152 goto nomem; 1153 1154 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1155 if (!reply) 1156 goto nomem; 1157 1158 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1159 return SCTP_DISPOSITION_CONSUME; 1160 1161 nomem: 1162 return SCTP_DISPOSITION_NOMEM; 1163 } 1164 1165 /* 1166 * Process the returning HEARTBEAT ACK. 1167 * 1168 * Section: 8.3 Path Heartbeat 1169 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1170 * should clear the error counter of the destination transport 1171 * address to which the HEARTBEAT was sent, and mark the destination 1172 * transport address as active if it is not so marked. The endpoint may 1173 * optionally report to the upper layer when an inactive destination 1174 * address is marked as active due to the reception of the latest 1175 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1176 * clear the association overall error count as well (as defined 1177 * in section 8.1). 1178 * 1179 * The receiver of the HEARTBEAT ACK should also perform an RTT 1180 * measurement for that destination transport address using the time 1181 * value carried in the HEARTBEAT ACK chunk. 1182 * 1183 * Verification Tag: 8.5 Verification Tag [Normal verification] 1184 * 1185 * Inputs 1186 * (endpoint, asoc, chunk) 1187 * 1188 * Outputs 1189 * (asoc, reply_msg, msg_up, timers, counters) 1190 * 1191 * The return value is the disposition of the chunk. 1192 */ 1193 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1194 const struct sctp_endpoint *ep, 1195 const struct sctp_association *asoc, 1196 const union sctp_subtype type, 1197 void *arg, 1198 struct sctp_cmd_seq *commands) 1199 { 1200 struct sctp_sender_hb_info *hbinfo; 1201 struct sctp_chunk *chunk = arg; 1202 struct sctp_transport *link; 1203 unsigned long max_interval; 1204 union sctp_addr from_addr; 1205 1206 if (!sctp_vtag_verify(chunk, asoc)) 1207 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1208 1209 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1210 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1211 sizeof(*hbinfo))) 1212 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1213 commands); 1214 1215 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1216 /* Make sure that the length of the parameter is what we expect */ 1217 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1218 return SCTP_DISPOSITION_DISCARD; 1219 1220 from_addr = hbinfo->daddr; 1221 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1222 1223 /* This should never happen, but lets log it if so. */ 1224 if (unlikely(!link)) { 1225 if (from_addr.sa.sa_family == AF_INET6) { 1226 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1227 __func__, 1228 asoc, 1229 &from_addr.v6.sin6_addr); 1230 } else { 1231 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1232 __func__, 1233 asoc, 1234 &from_addr.v4.sin_addr.s_addr); 1235 } 1236 return SCTP_DISPOSITION_DISCARD; 1237 } 1238 1239 /* Validate the 64-bit random nonce. */ 1240 if (hbinfo->hb_nonce != link->hb_nonce) 1241 return SCTP_DISPOSITION_DISCARD; 1242 1243 max_interval = link->hbinterval + link->rto; 1244 1245 /* Check if the timestamp looks valid. */ 1246 if (time_after(hbinfo->sent_at, jiffies) || 1247 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1248 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1249 "for transport:%p\n", __func__, link); 1250 1251 return SCTP_DISPOSITION_DISCARD; 1252 } 1253 1254 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1255 * the HEARTBEAT should clear the error counter of the 1256 * destination transport address to which the HEARTBEAT was 1257 * sent and mark the destination transport address as active if 1258 * it is not so marked. 1259 */ 1260 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1261 1262 return SCTP_DISPOSITION_CONSUME; 1263 } 1264 1265 /* Helper function to send out an abort for the restart 1266 * condition. 1267 */ 1268 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1269 struct sctp_chunk *init, 1270 struct sctp_cmd_seq *commands) 1271 { 1272 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1273 union sctp_addr_param *addrparm; 1274 struct sctp_errhdr *errhdr; 1275 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1276 struct sctp_endpoint *ep; 1277 struct sctp_packet *pkt; 1278 int len; 1279 1280 /* Build the error on the stack. We are way to malloc crazy 1281 * throughout the code today. 1282 */ 1283 errhdr = (struct sctp_errhdr *)buffer; 1284 addrparm = (union sctp_addr_param *)errhdr->variable; 1285 1286 /* Copy into a parm format. */ 1287 len = af->to_addr_param(ssa, addrparm); 1288 len += sizeof(*errhdr); 1289 1290 errhdr->cause = SCTP_ERROR_RESTART; 1291 errhdr->length = htons(len); 1292 1293 /* Assign to the control socket. */ 1294 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1295 1296 /* Association is NULL since this may be a restart attack and we 1297 * want to send back the attacker's vtag. 1298 */ 1299 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1300 1301 if (!pkt) 1302 goto out; 1303 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1304 1305 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1306 1307 /* Discard the rest of the inbound packet. */ 1308 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1309 1310 out: 1311 /* Even if there is no memory, treat as a failure so 1312 * the packet will get dropped. 1313 */ 1314 return 0; 1315 } 1316 1317 static bool list_has_sctp_addr(const struct list_head *list, 1318 union sctp_addr *ipaddr) 1319 { 1320 struct sctp_transport *addr; 1321 1322 list_for_each_entry(addr, list, transports) { 1323 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1324 return true; 1325 } 1326 1327 return false; 1328 } 1329 /* A restart is occurring, check to make sure no new addresses 1330 * are being added as we may be under a takeover attack. 1331 */ 1332 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1333 const struct sctp_association *asoc, 1334 struct sctp_chunk *init, 1335 struct sctp_cmd_seq *commands) 1336 { 1337 struct net *net = sock_net(new_asoc->base.sk); 1338 struct sctp_transport *new_addr; 1339 int ret = 1; 1340 1341 /* Implementor's Guide - Section 5.2.2 1342 * ... 1343 * Before responding the endpoint MUST check to see if the 1344 * unexpected INIT adds new addresses to the association. If new 1345 * addresses are added to the association, the endpoint MUST respond 1346 * with an ABORT.. 1347 */ 1348 1349 /* Search through all current addresses and make sure 1350 * we aren't adding any new ones. 1351 */ 1352 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1353 transports) { 1354 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1355 &new_addr->ipaddr)) { 1356 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1357 commands); 1358 ret = 0; 1359 break; 1360 } 1361 } 1362 1363 /* Return success if all addresses were found. */ 1364 return ret; 1365 } 1366 1367 /* Populate the verification/tie tags based on overlapping INIT 1368 * scenario. 1369 * 1370 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1371 */ 1372 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1373 const struct sctp_association *asoc) 1374 { 1375 switch (asoc->state) { 1376 1377 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1378 1379 case SCTP_STATE_COOKIE_WAIT: 1380 new_asoc->c.my_vtag = asoc->c.my_vtag; 1381 new_asoc->c.my_ttag = asoc->c.my_vtag; 1382 new_asoc->c.peer_ttag = 0; 1383 break; 1384 1385 case SCTP_STATE_COOKIE_ECHOED: 1386 new_asoc->c.my_vtag = asoc->c.my_vtag; 1387 new_asoc->c.my_ttag = asoc->c.my_vtag; 1388 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1389 break; 1390 1391 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1392 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1393 */ 1394 default: 1395 new_asoc->c.my_ttag = asoc->c.my_vtag; 1396 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1397 break; 1398 } 1399 1400 /* Other parameters for the endpoint SHOULD be copied from the 1401 * existing parameters of the association (e.g. number of 1402 * outbound streams) into the INIT ACK and cookie. 1403 */ 1404 new_asoc->rwnd = asoc->rwnd; 1405 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1406 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1407 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1408 } 1409 1410 /* 1411 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1412 * handling action. 1413 * 1414 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1415 * 1416 * Returns value representing action to be taken. These action values 1417 * correspond to Action/Description values in RFC 2960, Table 2. 1418 */ 1419 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1420 const struct sctp_association *asoc) 1421 { 1422 /* In this case, the peer may have restarted. */ 1423 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1424 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1425 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1426 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1427 return 'A'; 1428 1429 /* Collision case B. */ 1430 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1431 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1432 (0 == asoc->c.peer_vtag))) { 1433 return 'B'; 1434 } 1435 1436 /* Collision case D. */ 1437 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1438 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1439 return 'D'; 1440 1441 /* Collision case C. */ 1442 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1443 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1444 (0 == new_asoc->c.my_ttag) && 1445 (0 == new_asoc->c.peer_ttag)) 1446 return 'C'; 1447 1448 /* No match to any of the special cases; discard this packet. */ 1449 return 'E'; 1450 } 1451 1452 /* Common helper routine for both duplicate and simulataneous INIT 1453 * chunk handling. 1454 */ 1455 static enum sctp_disposition sctp_sf_do_unexpected_init( 1456 struct net *net, 1457 const struct sctp_endpoint *ep, 1458 const struct sctp_association *asoc, 1459 const union sctp_subtype type, 1460 void *arg, 1461 struct sctp_cmd_seq *commands) 1462 { 1463 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1464 struct sctp_unrecognized_param *unk_param; 1465 struct sctp_association *new_asoc; 1466 enum sctp_disposition retval; 1467 struct sctp_packet *packet; 1468 int len; 1469 1470 /* Update socket peer label if first association. */ 1471 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 1472 chunk->skb)) 1473 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1474 1475 /* 6.10 Bundling 1476 * An endpoint MUST NOT bundle INIT, INIT ACK or 1477 * SHUTDOWN COMPLETE with any other chunks. 1478 * 1479 * IG Section 2.11.2 1480 * Furthermore, we require that the receiver of an INIT chunk MUST 1481 * enforce these rules by silently discarding an arriving packet 1482 * with an INIT chunk that is bundled with other chunks. 1483 */ 1484 if (!chunk->singleton) 1485 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1486 1487 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1488 * Tag. 1489 */ 1490 if (chunk->sctp_hdr->vtag != 0) 1491 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1492 1493 /* Make sure that the INIT chunk has a valid length. 1494 * In this case, we generate a protocol violation since we have 1495 * an association established. 1496 */ 1497 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1498 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1499 commands); 1500 /* Grab the INIT header. */ 1501 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1502 1503 /* Tag the variable length parameters. */ 1504 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1505 1506 /* Verify the INIT chunk before processing it. */ 1507 err_chunk = NULL; 1508 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1509 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1510 &err_chunk)) { 1511 /* This chunk contains fatal error. It is to be discarded. 1512 * Send an ABORT, with causes if there is any. 1513 */ 1514 if (err_chunk) { 1515 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1516 (__u8 *)(err_chunk->chunk_hdr) + 1517 sizeof(struct sctp_chunkhdr), 1518 ntohs(err_chunk->chunk_hdr->length) - 1519 sizeof(struct sctp_chunkhdr)); 1520 1521 if (packet) { 1522 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1523 SCTP_PACKET(packet)); 1524 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1525 retval = SCTP_DISPOSITION_CONSUME; 1526 } else { 1527 retval = SCTP_DISPOSITION_NOMEM; 1528 } 1529 goto cleanup; 1530 } else { 1531 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1532 commands); 1533 } 1534 } 1535 1536 /* 1537 * Other parameters for the endpoint SHOULD be copied from the 1538 * existing parameters of the association (e.g. number of 1539 * outbound streams) into the INIT ACK and cookie. 1540 * FIXME: We are copying parameters from the endpoint not the 1541 * association. 1542 */ 1543 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1544 if (!new_asoc) 1545 goto nomem; 1546 1547 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1548 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1549 goto nomem; 1550 1551 /* In the outbound INIT ACK the endpoint MUST copy its current 1552 * Verification Tag and Peers Verification tag into a reserved 1553 * place (local tie-tag and per tie-tag) within the state cookie. 1554 */ 1555 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1556 (struct sctp_init_chunk *)chunk->chunk_hdr, 1557 GFP_ATOMIC)) 1558 goto nomem; 1559 1560 /* Make sure no new addresses are being added during the 1561 * restart. Do not do this check for COOKIE-WAIT state, 1562 * since there are no peer addresses to check against. 1563 * Upon return an ABORT will have been sent if needed. 1564 */ 1565 if (!sctp_state(asoc, COOKIE_WAIT)) { 1566 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1567 commands)) { 1568 retval = SCTP_DISPOSITION_CONSUME; 1569 goto nomem_retval; 1570 } 1571 } 1572 1573 sctp_tietags_populate(new_asoc, asoc); 1574 1575 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1576 1577 /* If there are errors need to be reported for unknown parameters, 1578 * make sure to reserve enough room in the INIT ACK for them. 1579 */ 1580 len = 0; 1581 if (err_chunk) { 1582 len = ntohs(err_chunk->chunk_hdr->length) - 1583 sizeof(struct sctp_chunkhdr); 1584 } 1585 1586 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1587 if (!repl) 1588 goto nomem; 1589 1590 /* If there are errors need to be reported for unknown parameters, 1591 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1592 * parameter. 1593 */ 1594 if (err_chunk) { 1595 /* Get the "Unrecognized parameter" parameter(s) out of the 1596 * ERROR chunk generated by sctp_verify_init(). Since the 1597 * error cause code for "unknown parameter" and the 1598 * "Unrecognized parameter" type is the same, we can 1599 * construct the parameters in INIT ACK by copying the 1600 * ERROR causes over. 1601 */ 1602 unk_param = (struct sctp_unrecognized_param *) 1603 ((__u8 *)(err_chunk->chunk_hdr) + 1604 sizeof(struct sctp_chunkhdr)); 1605 /* Replace the cause code with the "Unrecognized parameter" 1606 * parameter type. 1607 */ 1608 sctp_addto_chunk(repl, len, unk_param); 1609 } 1610 1611 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1612 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1613 1614 /* 1615 * Note: After sending out INIT ACK with the State Cookie parameter, 1616 * "Z" MUST NOT allocate any resources for this new association. 1617 * Otherwise, "Z" will be vulnerable to resource attacks. 1618 */ 1619 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1620 retval = SCTP_DISPOSITION_CONSUME; 1621 1622 return retval; 1623 1624 nomem: 1625 retval = SCTP_DISPOSITION_NOMEM; 1626 nomem_retval: 1627 if (new_asoc) 1628 sctp_association_free(new_asoc); 1629 cleanup: 1630 if (err_chunk) 1631 sctp_chunk_free(err_chunk); 1632 return retval; 1633 } 1634 1635 /* 1636 * Handle simultaneous INIT. 1637 * This means we started an INIT and then we got an INIT request from 1638 * our peer. 1639 * 1640 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1641 * This usually indicates an initialization collision, i.e., each 1642 * endpoint is attempting, at about the same time, to establish an 1643 * association with the other endpoint. 1644 * 1645 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1646 * endpoint MUST respond with an INIT ACK using the same parameters it 1647 * sent in its original INIT chunk (including its Verification Tag, 1648 * unchanged). These original parameters are combined with those from the 1649 * newly received INIT chunk. The endpoint shall also generate a State 1650 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1651 * INIT to calculate the State Cookie. 1652 * 1653 * After that, the endpoint MUST NOT change its state, the T1-init 1654 * timer shall be left running and the corresponding TCB MUST NOT be 1655 * destroyed. The normal procedures for handling State Cookies when 1656 * a TCB exists will resolve the duplicate INITs to a single association. 1657 * 1658 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1659 * its Tie-Tags with the Tag information of itself and its peer (see 1660 * section 5.2.2 for a description of the Tie-Tags). 1661 * 1662 * Verification Tag: Not explicit, but an INIT can not have a valid 1663 * verification tag, so we skip the check. 1664 * 1665 * Inputs 1666 * (endpoint, asoc, chunk) 1667 * 1668 * Outputs 1669 * (asoc, reply_msg, msg_up, timers, counters) 1670 * 1671 * The return value is the disposition of the chunk. 1672 */ 1673 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1674 struct net *net, 1675 const struct sctp_endpoint *ep, 1676 const struct sctp_association *asoc, 1677 const union sctp_subtype type, 1678 void *arg, 1679 struct sctp_cmd_seq *commands) 1680 { 1681 /* Call helper to do the real work for both simulataneous and 1682 * duplicate INIT chunk handling. 1683 */ 1684 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1685 } 1686 1687 /* 1688 * Handle duplicated INIT messages. These are usually delayed 1689 * restransmissions. 1690 * 1691 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1692 * COOKIE-ECHOED and COOKIE-WAIT 1693 * 1694 * Unless otherwise stated, upon reception of an unexpected INIT for 1695 * this association, the endpoint shall generate an INIT ACK with a 1696 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1697 * current Verification Tag and peer's Verification Tag into a reserved 1698 * place within the state cookie. We shall refer to these locations as 1699 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1700 * containing this INIT ACK MUST carry a Verification Tag value equal to 1701 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1702 * MUST contain a new Initiation Tag (randomly generated see Section 1703 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1704 * existing parameters of the association (e.g. number of outbound 1705 * streams) into the INIT ACK and cookie. 1706 * 1707 * After sending out the INIT ACK, the endpoint shall take no further 1708 * actions, i.e., the existing association, including its current state, 1709 * and the corresponding TCB MUST NOT be changed. 1710 * 1711 * Note: Only when a TCB exists and the association is not in a COOKIE- 1712 * WAIT state are the Tie-Tags populated. For a normal association INIT 1713 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1714 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1715 * State Cookie are populated as specified in section 5.2.1. 1716 * 1717 * Verification Tag: Not specified, but an INIT has no way of knowing 1718 * what the verification tag could be, so we ignore it. 1719 * 1720 * Inputs 1721 * (endpoint, asoc, chunk) 1722 * 1723 * Outputs 1724 * (asoc, reply_msg, msg_up, timers, counters) 1725 * 1726 * The return value is the disposition of the chunk. 1727 */ 1728 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1729 struct net *net, 1730 const struct sctp_endpoint *ep, 1731 const struct sctp_association *asoc, 1732 const union sctp_subtype type, 1733 void *arg, 1734 struct sctp_cmd_seq *commands) 1735 { 1736 /* Call helper to do the real work for both simulataneous and 1737 * duplicate INIT chunk handling. 1738 */ 1739 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1740 } 1741 1742 1743 /* 1744 * Unexpected INIT-ACK handler. 1745 * 1746 * Section 5.2.3 1747 * If an INIT ACK received by an endpoint in any state other than the 1748 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1749 * An unexpected INIT ACK usually indicates the processing of an old or 1750 * duplicated INIT chunk. 1751 */ 1752 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1753 struct net *net, 1754 const struct sctp_endpoint *ep, 1755 const struct sctp_association *asoc, 1756 const union sctp_subtype type, 1757 void *arg, 1758 struct sctp_cmd_seq *commands) 1759 { 1760 /* Per the above section, we'll discard the chunk if we have an 1761 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1762 */ 1763 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1764 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1765 else 1766 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1767 } 1768 1769 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1770 * 1771 * Section 5.2.4 1772 * A) In this case, the peer may have restarted. 1773 */ 1774 static enum sctp_disposition sctp_sf_do_dupcook_a( 1775 struct net *net, 1776 const struct sctp_endpoint *ep, 1777 const struct sctp_association *asoc, 1778 struct sctp_chunk *chunk, 1779 struct sctp_cmd_seq *commands, 1780 struct sctp_association *new_asoc) 1781 { 1782 struct sctp_init_chunk *peer_init; 1783 enum sctp_disposition disposition; 1784 struct sctp_ulpevent *ev; 1785 struct sctp_chunk *repl; 1786 struct sctp_chunk *err; 1787 1788 /* new_asoc is a brand-new association, so these are not yet 1789 * side effects--it is safe to run them here. 1790 */ 1791 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1792 1793 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1794 GFP_ATOMIC)) 1795 goto nomem; 1796 1797 /* Make sure no new addresses are being added during the 1798 * restart. Though this is a pretty complicated attack 1799 * since you'd have to get inside the cookie. 1800 */ 1801 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1802 return SCTP_DISPOSITION_CONSUME; 1803 } 1804 1805 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1806 * the peer has restarted (Action A), it MUST NOT setup a new 1807 * association but instead resend the SHUTDOWN ACK and send an ERROR 1808 * chunk with a "Cookie Received while Shutting Down" error cause to 1809 * its peer. 1810 */ 1811 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1812 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1813 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1814 chunk, commands); 1815 if (SCTP_DISPOSITION_NOMEM == disposition) 1816 goto nomem; 1817 1818 err = sctp_make_op_error(asoc, chunk, 1819 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1820 NULL, 0, 0); 1821 if (err) 1822 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1823 SCTP_CHUNK(err)); 1824 1825 return SCTP_DISPOSITION_CONSUME; 1826 } 1827 1828 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1829 * data. Consider the optional choice of resending of this data. 1830 */ 1831 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1832 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1833 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1834 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1835 1836 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1837 * and ASCONF-ACK cache. 1838 */ 1839 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1840 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1841 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1842 1843 repl = sctp_make_cookie_ack(new_asoc, chunk); 1844 if (!repl) 1845 goto nomem; 1846 1847 /* Report association restart to upper layer. */ 1848 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1849 new_asoc->c.sinit_num_ostreams, 1850 new_asoc->c.sinit_max_instreams, 1851 NULL, GFP_ATOMIC); 1852 if (!ev) 1853 goto nomem_ev; 1854 1855 /* Update the content of current association. */ 1856 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1857 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1858 if (sctp_state(asoc, SHUTDOWN_PENDING) && 1859 (sctp_sstate(asoc->base.sk, CLOSING) || 1860 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1861 /* if were currently in SHUTDOWN_PENDING, but the socket 1862 * has been closed by user, don't transition to ESTABLISHED. 1863 * Instead trigger SHUTDOWN bundled with COOKIE_ACK. 1864 */ 1865 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1866 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1867 SCTP_ST_CHUNK(0), NULL, 1868 commands); 1869 } else { 1870 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1871 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1872 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1873 } 1874 return SCTP_DISPOSITION_CONSUME; 1875 1876 nomem_ev: 1877 sctp_chunk_free(repl); 1878 nomem: 1879 return SCTP_DISPOSITION_NOMEM; 1880 } 1881 1882 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1883 * 1884 * Section 5.2.4 1885 * B) In this case, both sides may be attempting to start an association 1886 * at about the same time but the peer endpoint started its INIT 1887 * after responding to the local endpoint's INIT 1888 */ 1889 /* This case represents an initialization collision. */ 1890 static enum sctp_disposition sctp_sf_do_dupcook_b( 1891 struct net *net, 1892 const struct sctp_endpoint *ep, 1893 const struct sctp_association *asoc, 1894 struct sctp_chunk *chunk, 1895 struct sctp_cmd_seq *commands, 1896 struct sctp_association *new_asoc) 1897 { 1898 struct sctp_init_chunk *peer_init; 1899 struct sctp_chunk *repl; 1900 1901 /* new_asoc is a brand-new association, so these are not yet 1902 * side effects--it is safe to run them here. 1903 */ 1904 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1905 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1906 GFP_ATOMIC)) 1907 goto nomem; 1908 1909 /* Update the content of current association. */ 1910 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1911 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1912 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1913 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1914 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1915 1916 repl = sctp_make_cookie_ack(new_asoc, chunk); 1917 if (!repl) 1918 goto nomem; 1919 1920 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1921 1922 /* RFC 2960 5.1 Normal Establishment of an Association 1923 * 1924 * D) IMPLEMENTATION NOTE: An implementation may choose to 1925 * send the Communication Up notification to the SCTP user 1926 * upon reception of a valid COOKIE ECHO chunk. 1927 * 1928 * Sadly, this needs to be implemented as a side-effect, because 1929 * we are not guaranteed to have set the association id of the real 1930 * association and so these notifications need to be delayed until 1931 * the association id is allocated. 1932 */ 1933 1934 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1935 1936 /* Sockets API Draft Section 5.3.1.6 1937 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1938 * delivers this notification to inform the application that of the 1939 * peers requested adaptation layer. 1940 * 1941 * This also needs to be done as a side effect for the same reason as 1942 * above. 1943 */ 1944 if (asoc->peer.adaptation_ind) 1945 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1946 1947 if (!asoc->peer.auth_capable) 1948 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 1949 1950 return SCTP_DISPOSITION_CONSUME; 1951 1952 nomem: 1953 return SCTP_DISPOSITION_NOMEM; 1954 } 1955 1956 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1957 * 1958 * Section 5.2.4 1959 * C) In this case, the local endpoint's cookie has arrived late. 1960 * Before it arrived, the local endpoint sent an INIT and received an 1961 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1962 * but a new tag of its own. 1963 */ 1964 /* This case represents an initialization collision. */ 1965 static enum sctp_disposition sctp_sf_do_dupcook_c( 1966 struct net *net, 1967 const struct sctp_endpoint *ep, 1968 const struct sctp_association *asoc, 1969 struct sctp_chunk *chunk, 1970 struct sctp_cmd_seq *commands, 1971 struct sctp_association *new_asoc) 1972 { 1973 /* The cookie should be silently discarded. 1974 * The endpoint SHOULD NOT change states and should leave 1975 * any timers running. 1976 */ 1977 return SCTP_DISPOSITION_DISCARD; 1978 } 1979 1980 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1981 * 1982 * Section 5.2.4 1983 * 1984 * D) When both local and remote tags match the endpoint should always 1985 * enter the ESTABLISHED state, if it has not already done so. 1986 */ 1987 /* This case represents an initialization collision. */ 1988 static enum sctp_disposition sctp_sf_do_dupcook_d( 1989 struct net *net, 1990 const struct sctp_endpoint *ep, 1991 const struct sctp_association *asoc, 1992 struct sctp_chunk *chunk, 1993 struct sctp_cmd_seq *commands, 1994 struct sctp_association *new_asoc) 1995 { 1996 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 1997 struct sctp_chunk *repl; 1998 1999 /* Clarification from Implementor's Guide: 2000 * D) When both local and remote tags match the endpoint should 2001 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2002 * It should stop any cookie timer that may be running and send 2003 * a COOKIE ACK. 2004 */ 2005 2006 /* Don't accidentally move back into established state. */ 2007 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2008 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2009 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2010 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2011 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2012 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2013 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2014 SCTP_NULL()); 2015 2016 /* RFC 2960 5.1 Normal Establishment of an Association 2017 * 2018 * D) IMPLEMENTATION NOTE: An implementation may choose 2019 * to send the Communication Up notification to the 2020 * SCTP user upon reception of a valid COOKIE 2021 * ECHO chunk. 2022 */ 2023 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2024 SCTP_COMM_UP, 0, 2025 asoc->c.sinit_num_ostreams, 2026 asoc->c.sinit_max_instreams, 2027 NULL, GFP_ATOMIC); 2028 if (!ev) 2029 goto nomem; 2030 2031 /* Sockets API Draft Section 5.3.1.6 2032 * When a peer sends a Adaptation Layer Indication parameter, 2033 * SCTP delivers this notification to inform the application 2034 * that of the peers requested adaptation layer. 2035 */ 2036 if (asoc->peer.adaptation_ind) { 2037 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2038 GFP_ATOMIC); 2039 if (!ai_ev) 2040 goto nomem; 2041 2042 } 2043 2044 if (!asoc->peer.auth_capable) { 2045 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2046 SCTP_AUTH_NO_AUTH, 2047 GFP_ATOMIC); 2048 if (!auth_ev) 2049 goto nomem; 2050 } 2051 } 2052 2053 repl = sctp_make_cookie_ack(new_asoc, chunk); 2054 if (!repl) 2055 goto nomem; 2056 2057 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2058 2059 if (ev) 2060 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2061 SCTP_ULPEVENT(ev)); 2062 if (ai_ev) 2063 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2064 SCTP_ULPEVENT(ai_ev)); 2065 if (auth_ev) 2066 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2067 SCTP_ULPEVENT(auth_ev)); 2068 2069 return SCTP_DISPOSITION_CONSUME; 2070 2071 nomem: 2072 if (auth_ev) 2073 sctp_ulpevent_free(auth_ev); 2074 if (ai_ev) 2075 sctp_ulpevent_free(ai_ev); 2076 if (ev) 2077 sctp_ulpevent_free(ev); 2078 return SCTP_DISPOSITION_NOMEM; 2079 } 2080 2081 /* 2082 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2083 * chunk was retransmitted and then delayed in the network. 2084 * 2085 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2086 * 2087 * Verification Tag: None. Do cookie validation. 2088 * 2089 * Inputs 2090 * (endpoint, asoc, chunk) 2091 * 2092 * Outputs 2093 * (asoc, reply_msg, msg_up, timers, counters) 2094 * 2095 * The return value is the disposition of the chunk. 2096 */ 2097 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2098 struct net *net, 2099 const struct sctp_endpoint *ep, 2100 const struct sctp_association *asoc, 2101 const union sctp_subtype type, 2102 void *arg, 2103 struct sctp_cmd_seq *commands) 2104 { 2105 struct sctp_association *new_asoc; 2106 struct sctp_chunk *chunk = arg; 2107 enum sctp_disposition retval; 2108 struct sctp_chunk *err_chk_p; 2109 int error = 0; 2110 char action; 2111 2112 /* Make sure that the chunk has a valid length from the protocol 2113 * perspective. In this case check to make sure we have at least 2114 * enough for the chunk header. Cookie length verification is 2115 * done later. 2116 */ 2117 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2118 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2119 commands); 2120 2121 /* "Decode" the chunk. We have no optional parameters so we 2122 * are in good shape. 2123 */ 2124 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2125 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2126 sizeof(struct sctp_chunkhdr))) 2127 goto nomem; 2128 2129 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2130 * of a duplicate COOKIE ECHO match the Verification Tags of the 2131 * current association, consider the State Cookie valid even if 2132 * the lifespan is exceeded. 2133 */ 2134 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2135 &err_chk_p); 2136 2137 /* FIXME: 2138 * If the re-build failed, what is the proper error path 2139 * from here? 2140 * 2141 * [We should abort the association. --piggy] 2142 */ 2143 if (!new_asoc) { 2144 /* FIXME: Several errors are possible. A bad cookie should 2145 * be silently discarded, but think about logging it too. 2146 */ 2147 switch (error) { 2148 case -SCTP_IERROR_NOMEM: 2149 goto nomem; 2150 2151 case -SCTP_IERROR_STALE_COOKIE: 2152 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2153 err_chk_p); 2154 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2155 case -SCTP_IERROR_BAD_SIG: 2156 default: 2157 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2158 } 2159 } 2160 2161 /* Update socket peer label if first association. */ 2162 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 2163 chunk->skb)) 2164 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2165 2166 /* Set temp so that it won't be added into hashtable */ 2167 new_asoc->temp = 1; 2168 2169 /* Compare the tie_tag in cookie with the verification tag of 2170 * current association. 2171 */ 2172 action = sctp_tietags_compare(new_asoc, asoc); 2173 2174 switch (action) { 2175 case 'A': /* Association restart. */ 2176 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2177 new_asoc); 2178 break; 2179 2180 case 'B': /* Collision case B. */ 2181 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2182 new_asoc); 2183 break; 2184 2185 case 'C': /* Collision case C. */ 2186 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2187 new_asoc); 2188 break; 2189 2190 case 'D': /* Collision case D. */ 2191 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2192 new_asoc); 2193 break; 2194 2195 default: /* Discard packet for all others. */ 2196 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2197 break; 2198 } 2199 2200 /* Delete the tempory new association. */ 2201 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2202 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2203 2204 /* Restore association pointer to provide SCTP command interpeter 2205 * with a valid context in case it needs to manipulate 2206 * the queues */ 2207 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2208 SCTP_ASOC((struct sctp_association *)asoc)); 2209 2210 return retval; 2211 2212 nomem: 2213 return SCTP_DISPOSITION_NOMEM; 2214 } 2215 2216 /* 2217 * Process an ABORT. (SHUTDOWN-PENDING state) 2218 * 2219 * See sctp_sf_do_9_1_abort(). 2220 */ 2221 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2222 struct net *net, 2223 const struct sctp_endpoint *ep, 2224 const struct sctp_association *asoc, 2225 const union sctp_subtype type, 2226 void *arg, 2227 struct sctp_cmd_seq *commands) 2228 { 2229 struct sctp_chunk *chunk = arg; 2230 2231 if (!sctp_vtag_verify_either(chunk, asoc)) 2232 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2233 2234 /* Make sure that the ABORT chunk has a valid length. 2235 * Since this is an ABORT chunk, we have to discard it 2236 * because of the following text: 2237 * RFC 2960, Section 3.3.7 2238 * If an endpoint receives an ABORT with a format error or for an 2239 * association that doesn't exist, it MUST silently discard it. 2240 * Because the length is "invalid", we can't really discard just 2241 * as we do not know its true length. So, to be safe, discard the 2242 * packet. 2243 */ 2244 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2245 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2246 2247 /* ADD-IP: Special case for ABORT chunks 2248 * F4) One special consideration is that ABORT Chunks arriving 2249 * destined to the IP address being deleted MUST be 2250 * ignored (see Section 5.3.1 for further details). 2251 */ 2252 if (SCTP_ADDR_DEL == 2253 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2254 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2255 2256 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2257 } 2258 2259 /* 2260 * Process an ABORT. (SHUTDOWN-SENT state) 2261 * 2262 * See sctp_sf_do_9_1_abort(). 2263 */ 2264 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2265 struct net *net, 2266 const struct sctp_endpoint *ep, 2267 const struct sctp_association *asoc, 2268 const union sctp_subtype type, 2269 void *arg, 2270 struct sctp_cmd_seq *commands) 2271 { 2272 struct sctp_chunk *chunk = arg; 2273 2274 if (!sctp_vtag_verify_either(chunk, asoc)) 2275 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2276 2277 /* Make sure that the ABORT chunk has a valid length. 2278 * Since this is an ABORT chunk, we have to discard it 2279 * because of the following text: 2280 * RFC 2960, Section 3.3.7 2281 * If an endpoint receives an ABORT with a format error or for an 2282 * association that doesn't exist, it MUST silently discard it. 2283 * Because the length is "invalid", we can't really discard just 2284 * as we do not know its true length. So, to be safe, discard the 2285 * packet. 2286 */ 2287 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2288 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2289 2290 /* ADD-IP: Special case for ABORT chunks 2291 * F4) One special consideration is that ABORT Chunks arriving 2292 * destined to the IP address being deleted MUST be 2293 * ignored (see Section 5.3.1 for further details). 2294 */ 2295 if (SCTP_ADDR_DEL == 2296 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2297 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2298 2299 /* Stop the T2-shutdown timer. */ 2300 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2301 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2302 2303 /* Stop the T5-shutdown guard timer. */ 2304 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2305 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2306 2307 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2308 } 2309 2310 /* 2311 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2312 * 2313 * See sctp_sf_do_9_1_abort(). 2314 */ 2315 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2316 struct net *net, 2317 const struct sctp_endpoint *ep, 2318 const struct sctp_association *asoc, 2319 const union sctp_subtype type, 2320 void *arg, 2321 struct sctp_cmd_seq *commands) 2322 { 2323 /* The same T2 timer, so we should be able to use 2324 * common function with the SHUTDOWN-SENT state. 2325 */ 2326 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2327 } 2328 2329 /* 2330 * Handle an Error received in COOKIE_ECHOED state. 2331 * 2332 * Only handle the error type of stale COOKIE Error, the other errors will 2333 * be ignored. 2334 * 2335 * Inputs 2336 * (endpoint, asoc, chunk) 2337 * 2338 * Outputs 2339 * (asoc, reply_msg, msg_up, timers, counters) 2340 * 2341 * The return value is the disposition of the chunk. 2342 */ 2343 enum sctp_disposition sctp_sf_cookie_echoed_err( 2344 struct net *net, 2345 const struct sctp_endpoint *ep, 2346 const struct sctp_association *asoc, 2347 const union sctp_subtype type, 2348 void *arg, 2349 struct sctp_cmd_seq *commands) 2350 { 2351 struct sctp_chunk *chunk = arg; 2352 struct sctp_errhdr *err; 2353 2354 if (!sctp_vtag_verify(chunk, asoc)) 2355 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2356 2357 /* Make sure that the ERROR chunk has a valid length. 2358 * The parameter walking depends on this as well. 2359 */ 2360 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2361 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2362 commands); 2363 2364 /* Process the error here */ 2365 /* FUTURE FIXME: When PR-SCTP related and other optional 2366 * parms are emitted, this will have to change to handle multiple 2367 * errors. 2368 */ 2369 sctp_walk_errors(err, chunk->chunk_hdr) { 2370 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2371 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2372 arg, commands); 2373 } 2374 2375 /* It is possible to have malformed error causes, and that 2376 * will cause us to end the walk early. However, since 2377 * we are discarding the packet, there should be no adverse 2378 * affects. 2379 */ 2380 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2381 } 2382 2383 /* 2384 * Handle a Stale COOKIE Error 2385 * 2386 * Section: 5.2.6 Handle Stale COOKIE Error 2387 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2388 * one of the following three alternatives. 2389 * ... 2390 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2391 * Preservative parameter requesting an extension to the lifetime of 2392 * the State Cookie. When calculating the time extension, an 2393 * implementation SHOULD use the RTT information measured based on the 2394 * previous COOKIE ECHO / ERROR exchange, and should add no more 2395 * than 1 second beyond the measured RTT, due to long State Cookie 2396 * lifetimes making the endpoint more subject to a replay attack. 2397 * 2398 * Verification Tag: Not explicit, but safe to ignore. 2399 * 2400 * Inputs 2401 * (endpoint, asoc, chunk) 2402 * 2403 * Outputs 2404 * (asoc, reply_msg, msg_up, timers, counters) 2405 * 2406 * The return value is the disposition of the chunk. 2407 */ 2408 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2409 struct net *net, 2410 const struct sctp_endpoint *ep, 2411 const struct sctp_association *asoc, 2412 const union sctp_subtype type, 2413 void *arg, 2414 struct sctp_cmd_seq *commands) 2415 { 2416 int attempts = asoc->init_err_counter + 1; 2417 struct sctp_chunk *chunk = arg, *reply; 2418 struct sctp_cookie_preserve_param bht; 2419 struct sctp_bind_addr *bp; 2420 struct sctp_errhdr *err; 2421 u32 stale; 2422 2423 if (attempts > asoc->max_init_attempts) { 2424 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2425 SCTP_ERROR(ETIMEDOUT)); 2426 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2427 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2428 return SCTP_DISPOSITION_DELETE_TCB; 2429 } 2430 2431 err = (struct sctp_errhdr *)(chunk->skb->data); 2432 2433 /* When calculating the time extension, an implementation 2434 * SHOULD use the RTT information measured based on the 2435 * previous COOKIE ECHO / ERROR exchange, and should add no 2436 * more than 1 second beyond the measured RTT, due to long 2437 * State Cookie lifetimes making the endpoint more subject to 2438 * a replay attack. 2439 * Measure of Staleness's unit is usec. (1/1000000 sec) 2440 * Suggested Cookie Life-span Increment's unit is msec. 2441 * (1/1000 sec) 2442 * In general, if you use the suggested cookie life, the value 2443 * found in the field of measure of staleness should be doubled 2444 * to give ample time to retransmit the new cookie and thus 2445 * yield a higher probability of success on the reattempt. 2446 */ 2447 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2448 stale = (stale * 2) / 1000; 2449 2450 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2451 bht.param_hdr.length = htons(sizeof(bht)); 2452 bht.lifespan_increment = htonl(stale); 2453 2454 /* Build that new INIT chunk. */ 2455 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2456 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2457 if (!reply) 2458 goto nomem; 2459 2460 sctp_addto_chunk(reply, sizeof(bht), &bht); 2461 2462 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2463 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2464 2465 /* Stop pending T3-rtx and heartbeat timers */ 2466 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2467 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2468 2469 /* Delete non-primary peer ip addresses since we are transitioning 2470 * back to the COOKIE-WAIT state 2471 */ 2472 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2473 2474 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2475 * resend 2476 */ 2477 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2478 SCTP_TRANSPORT(asoc->peer.primary_path)); 2479 2480 /* Cast away the const modifier, as we want to just 2481 * rerun it through as a sideffect. 2482 */ 2483 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2484 2485 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2486 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2487 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2488 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2489 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2490 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2491 2492 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2493 2494 return SCTP_DISPOSITION_CONSUME; 2495 2496 nomem: 2497 return SCTP_DISPOSITION_NOMEM; 2498 } 2499 2500 /* 2501 * Process an ABORT. 2502 * 2503 * Section: 9.1 2504 * After checking the Verification Tag, the receiving endpoint shall 2505 * remove the association from its record, and shall report the 2506 * termination to its upper layer. 2507 * 2508 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2509 * B) Rules for packet carrying ABORT: 2510 * 2511 * - The endpoint shall always fill in the Verification Tag field of the 2512 * outbound packet with the destination endpoint's tag value if it 2513 * is known. 2514 * 2515 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2516 * MUST follow the procedure described in Section 8.4. 2517 * 2518 * - The receiver MUST accept the packet if the Verification Tag 2519 * matches either its own tag, OR the tag of its peer. Otherwise, the 2520 * receiver MUST silently discard the packet and take no further 2521 * action. 2522 * 2523 * Inputs 2524 * (endpoint, asoc, chunk) 2525 * 2526 * Outputs 2527 * (asoc, reply_msg, msg_up, timers, counters) 2528 * 2529 * The return value is the disposition of the chunk. 2530 */ 2531 enum sctp_disposition sctp_sf_do_9_1_abort( 2532 struct net *net, 2533 const struct sctp_endpoint *ep, 2534 const struct sctp_association *asoc, 2535 const union sctp_subtype type, 2536 void *arg, 2537 struct sctp_cmd_seq *commands) 2538 { 2539 struct sctp_chunk *chunk = arg; 2540 2541 if (!sctp_vtag_verify_either(chunk, asoc)) 2542 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2543 2544 /* Make sure that the ABORT chunk has a valid length. 2545 * Since this is an ABORT chunk, we have to discard it 2546 * because of the following text: 2547 * RFC 2960, Section 3.3.7 2548 * If an endpoint receives an ABORT with a format error or for an 2549 * association that doesn't exist, it MUST silently discard it. 2550 * Because the length is "invalid", we can't really discard just 2551 * as we do not know its true length. So, to be safe, discard the 2552 * packet. 2553 */ 2554 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2555 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2556 2557 /* ADD-IP: Special case for ABORT chunks 2558 * F4) One special consideration is that ABORT Chunks arriving 2559 * destined to the IP address being deleted MUST be 2560 * ignored (see Section 5.3.1 for further details). 2561 */ 2562 if (SCTP_ADDR_DEL == 2563 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2564 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2565 2566 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2567 } 2568 2569 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2570 struct net *net, 2571 const struct sctp_endpoint *ep, 2572 const struct sctp_association *asoc, 2573 const union sctp_subtype type, 2574 void *arg, 2575 struct sctp_cmd_seq *commands) 2576 { 2577 __be16 error = SCTP_ERROR_NO_ERROR; 2578 struct sctp_chunk *chunk = arg; 2579 unsigned int len; 2580 2581 /* See if we have an error cause code in the chunk. */ 2582 len = ntohs(chunk->chunk_hdr->length); 2583 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2584 struct sctp_errhdr *err; 2585 2586 sctp_walk_errors(err, chunk->chunk_hdr); 2587 if ((void *)err != (void *)chunk->chunk_end) 2588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 2589 commands); 2590 2591 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2592 } 2593 2594 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2595 /* ASSOC_FAILED will DELETE_TCB. */ 2596 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2597 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2598 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2599 2600 return SCTP_DISPOSITION_ABORT; 2601 } 2602 2603 /* 2604 * Process an ABORT. (COOKIE-WAIT state) 2605 * 2606 * See sctp_sf_do_9_1_abort() above. 2607 */ 2608 enum sctp_disposition sctp_sf_cookie_wait_abort( 2609 struct net *net, 2610 const struct sctp_endpoint *ep, 2611 const struct sctp_association *asoc, 2612 const union sctp_subtype type, 2613 void *arg, 2614 struct sctp_cmd_seq *commands) 2615 { 2616 __be16 error = SCTP_ERROR_NO_ERROR; 2617 struct sctp_chunk *chunk = arg; 2618 unsigned int len; 2619 2620 if (!sctp_vtag_verify_either(chunk, asoc)) 2621 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2622 2623 /* Make sure that the ABORT chunk has a valid length. 2624 * Since this is an ABORT chunk, we have to discard it 2625 * because of the following text: 2626 * RFC 2960, Section 3.3.7 2627 * If an endpoint receives an ABORT with a format error or for an 2628 * association that doesn't exist, it MUST silently discard it. 2629 * Because the length is "invalid", we can't really discard just 2630 * as we do not know its true length. So, to be safe, discard the 2631 * packet. 2632 */ 2633 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2634 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2635 2636 /* See if we have an error cause code in the chunk. */ 2637 len = ntohs(chunk->chunk_hdr->length); 2638 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2639 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2640 2641 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2642 chunk->transport); 2643 } 2644 2645 /* 2646 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2647 */ 2648 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2649 struct net *net, 2650 const struct sctp_endpoint *ep, 2651 const struct sctp_association *asoc, 2652 const union sctp_subtype type, 2653 void *arg, 2654 struct sctp_cmd_seq *commands) 2655 { 2656 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2657 ENOPROTOOPT, asoc, 2658 (struct sctp_transport *)arg); 2659 } 2660 2661 /* 2662 * Process an ABORT. (COOKIE-ECHOED state) 2663 */ 2664 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2665 struct net *net, 2666 const struct sctp_endpoint *ep, 2667 const struct sctp_association *asoc, 2668 const union sctp_subtype type, 2669 void *arg, 2670 struct sctp_cmd_seq *commands) 2671 { 2672 /* There is a single T1 timer, so we should be able to use 2673 * common function with the COOKIE-WAIT state. 2674 */ 2675 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2676 } 2677 2678 /* 2679 * Stop T1 timer and abort association with "INIT failed". 2680 * 2681 * This is common code called by several sctp_sf_*_abort() functions above. 2682 */ 2683 static enum sctp_disposition sctp_stop_t1_and_abort( 2684 struct net *net, 2685 struct sctp_cmd_seq *commands, 2686 __be16 error, int sk_err, 2687 const struct sctp_association *asoc, 2688 struct sctp_transport *transport) 2689 { 2690 pr_debug("%s: ABORT received (INIT)\n", __func__); 2691 2692 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2693 SCTP_STATE(SCTP_STATE_CLOSED)); 2694 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2695 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2696 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2697 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2698 /* CMD_INIT_FAILED will DELETE_TCB. */ 2699 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2700 SCTP_PERR(error)); 2701 2702 return SCTP_DISPOSITION_ABORT; 2703 } 2704 2705 /* 2706 * sctp_sf_do_9_2_shut 2707 * 2708 * Section: 9.2 2709 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2710 * - enter the SHUTDOWN-RECEIVED state, 2711 * 2712 * - stop accepting new data from its SCTP user 2713 * 2714 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2715 * that all its outstanding DATA chunks have been received by the 2716 * SHUTDOWN sender. 2717 * 2718 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2719 * send a SHUTDOWN in response to a ULP request. And should discard 2720 * subsequent SHUTDOWN chunks. 2721 * 2722 * If there are still outstanding DATA chunks left, the SHUTDOWN 2723 * receiver shall continue to follow normal data transmission 2724 * procedures defined in Section 6 until all outstanding DATA chunks 2725 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2726 * new data from its SCTP user. 2727 * 2728 * Verification Tag: 8.5 Verification Tag [Normal verification] 2729 * 2730 * Inputs 2731 * (endpoint, asoc, chunk) 2732 * 2733 * Outputs 2734 * (asoc, reply_msg, msg_up, timers, counters) 2735 * 2736 * The return value is the disposition of the chunk. 2737 */ 2738 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2739 struct net *net, 2740 const struct sctp_endpoint *ep, 2741 const struct sctp_association *asoc, 2742 const union sctp_subtype type, 2743 void *arg, 2744 struct sctp_cmd_seq *commands) 2745 { 2746 enum sctp_disposition disposition; 2747 struct sctp_chunk *chunk = arg; 2748 struct sctp_shutdownhdr *sdh; 2749 struct sctp_ulpevent *ev; 2750 __u32 ctsn; 2751 2752 if (!sctp_vtag_verify(chunk, asoc)) 2753 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2754 2755 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2756 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2757 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2758 commands); 2759 2760 /* Convert the elaborate header. */ 2761 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2762 skb_pull(chunk->skb, sizeof(*sdh)); 2763 chunk->subh.shutdown_hdr = sdh; 2764 ctsn = ntohl(sdh->cum_tsn_ack); 2765 2766 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2767 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2768 asoc->ctsn_ack_point); 2769 2770 return SCTP_DISPOSITION_DISCARD; 2771 } 2772 2773 /* If Cumulative TSN Ack beyond the max tsn currently 2774 * send, terminating the association and respond to the 2775 * sender with an ABORT. 2776 */ 2777 if (!TSN_lt(ctsn, asoc->next_tsn)) 2778 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2779 2780 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2781 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2782 * inform the application that it should cease sending data. 2783 */ 2784 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2785 if (!ev) { 2786 disposition = SCTP_DISPOSITION_NOMEM; 2787 goto out; 2788 } 2789 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2790 2791 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2792 * - enter the SHUTDOWN-RECEIVED state, 2793 * - stop accepting new data from its SCTP user 2794 * 2795 * [This is implicit in the new state.] 2796 */ 2797 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2798 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2799 disposition = SCTP_DISPOSITION_CONSUME; 2800 2801 if (sctp_outq_is_empty(&asoc->outqueue)) { 2802 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2803 arg, commands); 2804 } 2805 2806 if (SCTP_DISPOSITION_NOMEM == disposition) 2807 goto out; 2808 2809 /* - verify, by checking the Cumulative TSN Ack field of the 2810 * chunk, that all its outstanding DATA chunks have been 2811 * received by the SHUTDOWN sender. 2812 */ 2813 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2814 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2815 2816 out: 2817 return disposition; 2818 } 2819 2820 /* 2821 * sctp_sf_do_9_2_shut_ctsn 2822 * 2823 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2824 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2825 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2826 * MUST be processed. 2827 */ 2828 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2829 struct net *net, 2830 const struct sctp_endpoint *ep, 2831 const struct sctp_association *asoc, 2832 const union sctp_subtype type, 2833 void *arg, 2834 struct sctp_cmd_seq *commands) 2835 { 2836 struct sctp_chunk *chunk = arg; 2837 struct sctp_shutdownhdr *sdh; 2838 __u32 ctsn; 2839 2840 if (!sctp_vtag_verify(chunk, asoc)) 2841 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2842 2843 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2844 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2845 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2846 commands); 2847 2848 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2849 ctsn = ntohl(sdh->cum_tsn_ack); 2850 2851 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2852 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2853 asoc->ctsn_ack_point); 2854 2855 return SCTP_DISPOSITION_DISCARD; 2856 } 2857 2858 /* If Cumulative TSN Ack beyond the max tsn currently 2859 * send, terminating the association and respond to the 2860 * sender with an ABORT. 2861 */ 2862 if (!TSN_lt(ctsn, asoc->next_tsn)) 2863 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2864 2865 /* verify, by checking the Cumulative TSN Ack field of the 2866 * chunk, that all its outstanding DATA chunks have been 2867 * received by the SHUTDOWN sender. 2868 */ 2869 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2870 SCTP_BE32(sdh->cum_tsn_ack)); 2871 2872 return SCTP_DISPOSITION_CONSUME; 2873 } 2874 2875 /* RFC 2960 9.2 2876 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2877 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2878 * transport addresses (either in the IP addresses or in the INIT chunk) 2879 * that belong to this association, it should discard the INIT chunk and 2880 * retransmit the SHUTDOWN ACK chunk. 2881 */ 2882 enum sctp_disposition sctp_sf_do_9_2_reshutack( 2883 struct net *net, 2884 const struct sctp_endpoint *ep, 2885 const struct sctp_association *asoc, 2886 const union sctp_subtype type, 2887 void *arg, 2888 struct sctp_cmd_seq *commands) 2889 { 2890 struct sctp_chunk *chunk = arg; 2891 struct sctp_chunk *reply; 2892 2893 /* Make sure that the chunk has a valid length */ 2894 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2895 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2896 commands); 2897 2898 /* Since we are not going to really process this INIT, there 2899 * is no point in verifying chunk boundries. Just generate 2900 * the SHUTDOWN ACK. 2901 */ 2902 reply = sctp_make_shutdown_ack(asoc, chunk); 2903 if (NULL == reply) 2904 goto nomem; 2905 2906 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2907 * the T2-SHUTDOWN timer. 2908 */ 2909 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2910 2911 /* and restart the T2-shutdown timer. */ 2912 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2913 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2914 2915 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2916 2917 return SCTP_DISPOSITION_CONSUME; 2918 nomem: 2919 return SCTP_DISPOSITION_NOMEM; 2920 } 2921 2922 /* 2923 * sctp_sf_do_ecn_cwr 2924 * 2925 * Section: Appendix A: Explicit Congestion Notification 2926 * 2927 * CWR: 2928 * 2929 * RFC 2481 details a specific bit for a sender to send in the header of 2930 * its next outbound TCP segment to indicate to its peer that it has 2931 * reduced its congestion window. This is termed the CWR bit. For 2932 * SCTP the same indication is made by including the CWR chunk. 2933 * This chunk contains one data element, i.e. the TSN number that 2934 * was sent in the ECNE chunk. This element represents the lowest 2935 * TSN number in the datagram that was originally marked with the 2936 * CE bit. 2937 * 2938 * Verification Tag: 8.5 Verification Tag [Normal verification] 2939 * Inputs 2940 * (endpoint, asoc, chunk) 2941 * 2942 * Outputs 2943 * (asoc, reply_msg, msg_up, timers, counters) 2944 * 2945 * The return value is the disposition of the chunk. 2946 */ 2947 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 2948 const struct sctp_endpoint *ep, 2949 const struct sctp_association *asoc, 2950 const union sctp_subtype type, 2951 void *arg, 2952 struct sctp_cmd_seq *commands) 2953 { 2954 struct sctp_chunk *chunk = arg; 2955 struct sctp_cwrhdr *cwr; 2956 u32 lowest_tsn; 2957 2958 if (!sctp_vtag_verify(chunk, asoc)) 2959 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2960 2961 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 2962 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2963 commands); 2964 2965 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 2966 skb_pull(chunk->skb, sizeof(*cwr)); 2967 2968 lowest_tsn = ntohl(cwr->lowest_tsn); 2969 2970 /* Does this CWR ack the last sent congestion notification? */ 2971 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2972 /* Stop sending ECNE. */ 2973 sctp_add_cmd_sf(commands, 2974 SCTP_CMD_ECN_CWR, 2975 SCTP_U32(lowest_tsn)); 2976 } 2977 return SCTP_DISPOSITION_CONSUME; 2978 } 2979 2980 /* 2981 * sctp_sf_do_ecne 2982 * 2983 * Section: Appendix A: Explicit Congestion Notification 2984 * 2985 * ECN-Echo 2986 * 2987 * RFC 2481 details a specific bit for a receiver to send back in its 2988 * TCP acknowledgements to notify the sender of the Congestion 2989 * Experienced (CE) bit having arrived from the network. For SCTP this 2990 * same indication is made by including the ECNE chunk. This chunk 2991 * contains one data element, i.e. the lowest TSN associated with the IP 2992 * datagram marked with the CE bit..... 2993 * 2994 * Verification Tag: 8.5 Verification Tag [Normal verification] 2995 * Inputs 2996 * (endpoint, asoc, chunk) 2997 * 2998 * Outputs 2999 * (asoc, reply_msg, msg_up, timers, counters) 3000 * 3001 * The return value is the disposition of the chunk. 3002 */ 3003 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3004 const struct sctp_endpoint *ep, 3005 const struct sctp_association *asoc, 3006 const union sctp_subtype type, 3007 void *arg, struct sctp_cmd_seq *commands) 3008 { 3009 struct sctp_chunk *chunk = arg; 3010 struct sctp_ecnehdr *ecne; 3011 3012 if (!sctp_vtag_verify(chunk, asoc)) 3013 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3014 3015 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3016 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3017 commands); 3018 3019 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3020 skb_pull(chunk->skb, sizeof(*ecne)); 3021 3022 /* If this is a newer ECNE than the last CWR packet we sent out */ 3023 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3024 SCTP_U32(ntohl(ecne->lowest_tsn))); 3025 3026 return SCTP_DISPOSITION_CONSUME; 3027 } 3028 3029 /* 3030 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3031 * 3032 * The SCTP endpoint MUST always acknowledge the reception of each valid 3033 * DATA chunk. 3034 * 3035 * The guidelines on delayed acknowledgement algorithm specified in 3036 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3037 * acknowledgement SHOULD be generated for at least every second packet 3038 * (not every second DATA chunk) received, and SHOULD be generated within 3039 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3040 * situations it may be beneficial for an SCTP transmitter to be more 3041 * conservative than the algorithms detailed in this document allow. 3042 * However, an SCTP transmitter MUST NOT be more aggressive than the 3043 * following algorithms allow. 3044 * 3045 * A SCTP receiver MUST NOT generate more than one SACK for every 3046 * incoming packet, other than to update the offered window as the 3047 * receiving application consumes new data. 3048 * 3049 * Verification Tag: 8.5 Verification Tag [Normal verification] 3050 * 3051 * Inputs 3052 * (endpoint, asoc, chunk) 3053 * 3054 * Outputs 3055 * (asoc, reply_msg, msg_up, timers, counters) 3056 * 3057 * The return value is the disposition of the chunk. 3058 */ 3059 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3060 const struct sctp_endpoint *ep, 3061 const struct sctp_association *asoc, 3062 const union sctp_subtype type, 3063 void *arg, 3064 struct sctp_cmd_seq *commands) 3065 { 3066 union sctp_arg force = SCTP_NOFORCE(); 3067 struct sctp_chunk *chunk = arg; 3068 int error; 3069 3070 if (!sctp_vtag_verify(chunk, asoc)) { 3071 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3072 SCTP_NULL()); 3073 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3074 } 3075 3076 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3077 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3078 commands); 3079 3080 error = sctp_eat_data(asoc, chunk, commands); 3081 switch (error) { 3082 case SCTP_IERROR_NO_ERROR: 3083 break; 3084 case SCTP_IERROR_HIGH_TSN: 3085 case SCTP_IERROR_BAD_STREAM: 3086 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3087 goto discard_noforce; 3088 case SCTP_IERROR_DUP_TSN: 3089 case SCTP_IERROR_IGNORE_TSN: 3090 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3091 goto discard_force; 3092 case SCTP_IERROR_NO_DATA: 3093 return SCTP_DISPOSITION_ABORT; 3094 case SCTP_IERROR_PROTO_VIOLATION: 3095 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3096 (u8 *)chunk->subh.data_hdr, 3097 sctp_datahdr_len(&asoc->stream)); 3098 default: 3099 BUG(); 3100 } 3101 3102 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3103 force = SCTP_FORCE(); 3104 3105 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3106 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3107 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3108 } 3109 3110 /* If this is the last chunk in a packet, we need to count it 3111 * toward sack generation. Note that we need to SACK every 3112 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3113 * THEM. We elect to NOT generate SACK's if the chunk fails 3114 * the verification tag test. 3115 * 3116 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3117 * 3118 * The SCTP endpoint MUST always acknowledge the reception of 3119 * each valid DATA chunk. 3120 * 3121 * The guidelines on delayed acknowledgement algorithm 3122 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3123 * Specifically, an acknowledgement SHOULD be generated for at 3124 * least every second packet (not every second DATA chunk) 3125 * received, and SHOULD be generated within 200 ms of the 3126 * arrival of any unacknowledged DATA chunk. In some 3127 * situations it may be beneficial for an SCTP transmitter to 3128 * be more conservative than the algorithms detailed in this 3129 * document allow. However, an SCTP transmitter MUST NOT be 3130 * more aggressive than the following algorithms allow. 3131 */ 3132 if (chunk->end_of_packet) 3133 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3134 3135 return SCTP_DISPOSITION_CONSUME; 3136 3137 discard_force: 3138 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3139 * 3140 * When a packet arrives with duplicate DATA chunk(s) and with 3141 * no new DATA chunk(s), the endpoint MUST immediately send a 3142 * SACK with no delay. If a packet arrives with duplicate 3143 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3144 * MAY immediately send a SACK. Normally receipt of duplicate 3145 * DATA chunks will occur when the original SACK chunk was lost 3146 * and the peer's RTO has expired. The duplicate TSN number(s) 3147 * SHOULD be reported in the SACK as duplicate. 3148 */ 3149 /* In our case, we split the MAY SACK advice up whether or not 3150 * the last chunk is a duplicate.' 3151 */ 3152 if (chunk->end_of_packet) 3153 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3154 return SCTP_DISPOSITION_DISCARD; 3155 3156 discard_noforce: 3157 if (chunk->end_of_packet) 3158 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3159 3160 return SCTP_DISPOSITION_DISCARD; 3161 } 3162 3163 /* 3164 * sctp_sf_eat_data_fast_4_4 3165 * 3166 * Section: 4 (4) 3167 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3168 * DATA chunks without delay. 3169 * 3170 * Verification Tag: 8.5 Verification Tag [Normal verification] 3171 * Inputs 3172 * (endpoint, asoc, chunk) 3173 * 3174 * Outputs 3175 * (asoc, reply_msg, msg_up, timers, counters) 3176 * 3177 * The return value is the disposition of the chunk. 3178 */ 3179 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3180 struct net *net, 3181 const struct sctp_endpoint *ep, 3182 const struct sctp_association *asoc, 3183 const union sctp_subtype type, 3184 void *arg, 3185 struct sctp_cmd_seq *commands) 3186 { 3187 struct sctp_chunk *chunk = arg; 3188 int error; 3189 3190 if (!sctp_vtag_verify(chunk, asoc)) { 3191 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3192 SCTP_NULL()); 3193 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3194 } 3195 3196 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3197 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3198 commands); 3199 3200 error = sctp_eat_data(asoc, chunk, commands); 3201 switch (error) { 3202 case SCTP_IERROR_NO_ERROR: 3203 case SCTP_IERROR_HIGH_TSN: 3204 case SCTP_IERROR_DUP_TSN: 3205 case SCTP_IERROR_IGNORE_TSN: 3206 case SCTP_IERROR_BAD_STREAM: 3207 break; 3208 case SCTP_IERROR_NO_DATA: 3209 return SCTP_DISPOSITION_ABORT; 3210 case SCTP_IERROR_PROTO_VIOLATION: 3211 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3212 (u8 *)chunk->subh.data_hdr, 3213 sctp_datahdr_len(&asoc->stream)); 3214 default: 3215 BUG(); 3216 } 3217 3218 /* Go a head and force a SACK, since we are shutting down. */ 3219 3220 /* Implementor's Guide. 3221 * 3222 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3223 * respond to each received packet containing one or more DATA chunk(s) 3224 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3225 */ 3226 if (chunk->end_of_packet) { 3227 /* We must delay the chunk creation since the cumulative 3228 * TSN has not been updated yet. 3229 */ 3230 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3231 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3232 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3233 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3234 } 3235 3236 return SCTP_DISPOSITION_CONSUME; 3237 } 3238 3239 /* 3240 * Section: 6.2 Processing a Received SACK 3241 * D) Any time a SACK arrives, the endpoint performs the following: 3242 * 3243 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3244 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3245 * increasing, a SACK whose Cumulative TSN Ack is less than the 3246 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3247 * 3248 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3249 * of bytes still outstanding after processing the Cumulative TSN Ack 3250 * and the Gap Ack Blocks. 3251 * 3252 * iii) If the SACK is missing a TSN that was previously 3253 * acknowledged via a Gap Ack Block (e.g., the data receiver 3254 * reneged on the data), then mark the corresponding DATA chunk 3255 * as available for retransmit: Mark it as missing for fast 3256 * retransmit as described in Section 7.2.4 and if no retransmit 3257 * timer is running for the destination address to which the DATA 3258 * chunk was originally transmitted, then T3-rtx is started for 3259 * that destination address. 3260 * 3261 * Verification Tag: 8.5 Verification Tag [Normal verification] 3262 * 3263 * Inputs 3264 * (endpoint, asoc, chunk) 3265 * 3266 * Outputs 3267 * (asoc, reply_msg, msg_up, timers, counters) 3268 * 3269 * The return value is the disposition of the chunk. 3270 */ 3271 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3272 const struct sctp_endpoint *ep, 3273 const struct sctp_association *asoc, 3274 const union sctp_subtype type, 3275 void *arg, 3276 struct sctp_cmd_seq *commands) 3277 { 3278 struct sctp_chunk *chunk = arg; 3279 struct sctp_sackhdr *sackh; 3280 __u32 ctsn; 3281 3282 trace_sctp_probe(ep, asoc, chunk); 3283 3284 if (!sctp_vtag_verify(chunk, asoc)) 3285 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3286 3287 /* Make sure that the SACK chunk has a valid length. */ 3288 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3289 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3290 commands); 3291 3292 /* Pull the SACK chunk from the data buffer */ 3293 sackh = sctp_sm_pull_sack(chunk); 3294 /* Was this a bogus SACK? */ 3295 if (!sackh) 3296 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3297 chunk->subh.sack_hdr = sackh; 3298 ctsn = ntohl(sackh->cum_tsn_ack); 3299 3300 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3301 * Ack Point, then drop the SACK. Since Cumulative TSN 3302 * Ack is monotonically increasing, a SACK whose 3303 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3304 * Point indicates an out-of-order SACK. 3305 */ 3306 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3307 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3308 asoc->ctsn_ack_point); 3309 3310 return SCTP_DISPOSITION_DISCARD; 3311 } 3312 3313 /* If Cumulative TSN Ack beyond the max tsn currently 3314 * send, terminating the association and respond to the 3315 * sender with an ABORT. 3316 */ 3317 if (!TSN_lt(ctsn, asoc->next_tsn)) 3318 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3319 3320 /* Return this SACK for further processing. */ 3321 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3322 3323 /* Note: We do the rest of the work on the PROCESS_SACK 3324 * sideeffect. 3325 */ 3326 return SCTP_DISPOSITION_CONSUME; 3327 } 3328 3329 /* 3330 * Generate an ABORT in response to a packet. 3331 * 3332 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3333 * 3334 * 8) The receiver should respond to the sender of the OOTB packet with 3335 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3336 * MUST fill in the Verification Tag field of the outbound packet 3337 * with the value found in the Verification Tag field of the OOTB 3338 * packet and set the T-bit in the Chunk Flags to indicate that the 3339 * Verification Tag is reflected. After sending this ABORT, the 3340 * receiver of the OOTB packet shall discard the OOTB packet and take 3341 * no further action. 3342 * 3343 * Verification Tag: 3344 * 3345 * The return value is the disposition of the chunk. 3346 */ 3347 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3348 struct net *net, 3349 const struct sctp_endpoint *ep, 3350 const struct sctp_association *asoc, 3351 const union sctp_subtype type, 3352 void *arg, 3353 struct sctp_cmd_seq *commands) 3354 { 3355 struct sctp_packet *packet = NULL; 3356 struct sctp_chunk *chunk = arg; 3357 struct sctp_chunk *abort; 3358 3359 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3360 if (!packet) 3361 return SCTP_DISPOSITION_NOMEM; 3362 3363 /* Make an ABORT. The T bit will be set if the asoc 3364 * is NULL. 3365 */ 3366 abort = sctp_make_abort(asoc, chunk, 0); 3367 if (!abort) { 3368 sctp_ootb_pkt_free(packet); 3369 return SCTP_DISPOSITION_NOMEM; 3370 } 3371 3372 /* Reflect vtag if T-Bit is set */ 3373 if (sctp_test_T_bit(abort)) 3374 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3375 3376 /* Set the skb to the belonging sock for accounting. */ 3377 abort->skb->sk = ep->base.sk; 3378 3379 sctp_packet_append_chunk(packet, abort); 3380 3381 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3382 SCTP_PACKET(packet)); 3383 3384 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3385 3386 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3387 return SCTP_DISPOSITION_CONSUME; 3388 } 3389 3390 /* 3391 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3392 * event as ULP notification for each cause included in the chunk. 3393 * 3394 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3395 * 3396 * The return value is the disposition of the chunk. 3397 */ 3398 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3399 const struct sctp_endpoint *ep, 3400 const struct sctp_association *asoc, 3401 const union sctp_subtype type, 3402 void *arg, 3403 struct sctp_cmd_seq *commands) 3404 { 3405 struct sctp_chunk *chunk = arg; 3406 struct sctp_errhdr *err; 3407 3408 if (!sctp_vtag_verify(chunk, asoc)) 3409 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3410 3411 /* Make sure that the ERROR chunk has a valid length. */ 3412 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3413 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3414 commands); 3415 sctp_walk_errors(err, chunk->chunk_hdr); 3416 if ((void *)err != (void *)chunk->chunk_end) 3417 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3418 (void *)err, commands); 3419 3420 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3421 SCTP_CHUNK(chunk)); 3422 3423 return SCTP_DISPOSITION_CONSUME; 3424 } 3425 3426 /* 3427 * Process an inbound SHUTDOWN ACK. 3428 * 3429 * From Section 9.2: 3430 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3431 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3432 * peer, and remove all record of the association. 3433 * 3434 * The return value is the disposition. 3435 */ 3436 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3437 const struct sctp_endpoint *ep, 3438 const struct sctp_association *asoc, 3439 const union sctp_subtype type, 3440 void *arg, 3441 struct sctp_cmd_seq *commands) 3442 { 3443 struct sctp_chunk *chunk = arg; 3444 struct sctp_chunk *reply; 3445 struct sctp_ulpevent *ev; 3446 3447 if (!sctp_vtag_verify(chunk, asoc)) 3448 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3449 3450 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3451 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3452 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3453 commands); 3454 /* 10.2 H) SHUTDOWN COMPLETE notification 3455 * 3456 * When SCTP completes the shutdown procedures (section 9.2) this 3457 * notification is passed to the upper layer. 3458 */ 3459 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3460 0, 0, 0, NULL, GFP_ATOMIC); 3461 if (!ev) 3462 goto nomem; 3463 3464 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3465 reply = sctp_make_shutdown_complete(asoc, chunk); 3466 if (!reply) 3467 goto nomem_chunk; 3468 3469 /* Do all the commands now (after allocation), so that we 3470 * have consistent state if memory allocation failes 3471 */ 3472 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3473 3474 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3475 * stop the T2-shutdown timer, 3476 */ 3477 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3478 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3479 3480 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3481 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3482 3483 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3484 SCTP_STATE(SCTP_STATE_CLOSED)); 3485 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3486 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3487 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3488 3489 /* ...and remove all record of the association. */ 3490 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3491 return SCTP_DISPOSITION_DELETE_TCB; 3492 3493 nomem_chunk: 3494 sctp_ulpevent_free(ev); 3495 nomem: 3496 return SCTP_DISPOSITION_NOMEM; 3497 } 3498 3499 /* 3500 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3501 * 3502 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3503 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3504 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3505 * packet must fill in the Verification Tag field of the outbound 3506 * packet with the Verification Tag received in the SHUTDOWN ACK and 3507 * set the T-bit in the Chunk Flags to indicate that the Verification 3508 * Tag is reflected. 3509 * 3510 * 8) The receiver should respond to the sender of the OOTB packet with 3511 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3512 * MUST fill in the Verification Tag field of the outbound packet 3513 * with the value found in the Verification Tag field of the OOTB 3514 * packet and set the T-bit in the Chunk Flags to indicate that the 3515 * Verification Tag is reflected. After sending this ABORT, the 3516 * receiver of the OOTB packet shall discard the OOTB packet and take 3517 * no further action. 3518 */ 3519 enum sctp_disposition sctp_sf_ootb(struct net *net, 3520 const struct sctp_endpoint *ep, 3521 const struct sctp_association *asoc, 3522 const union sctp_subtype type, 3523 void *arg, struct sctp_cmd_seq *commands) 3524 { 3525 struct sctp_chunk *chunk = arg; 3526 struct sk_buff *skb = chunk->skb; 3527 struct sctp_chunkhdr *ch; 3528 struct sctp_errhdr *err; 3529 int ootb_cookie_ack = 0; 3530 int ootb_shut_ack = 0; 3531 __u8 *ch_end; 3532 3533 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3534 3535 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3536 do { 3537 /* Report violation if the chunk is less then minimal */ 3538 if (ntohs(ch->length) < sizeof(*ch)) 3539 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3540 commands); 3541 3542 /* Report violation if chunk len overflows */ 3543 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3544 if (ch_end > skb_tail_pointer(skb)) 3545 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3546 commands); 3547 3548 /* Now that we know we at least have a chunk header, 3549 * do things that are type appropriate. 3550 */ 3551 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3552 ootb_shut_ack = 1; 3553 3554 /* RFC 2960, Section 3.3.7 3555 * Moreover, under any circumstances, an endpoint that 3556 * receives an ABORT MUST NOT respond to that ABORT by 3557 * sending an ABORT of its own. 3558 */ 3559 if (SCTP_CID_ABORT == ch->type) 3560 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3561 3562 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3563 * or a COOKIE ACK the SCTP Packet should be silently 3564 * discarded. 3565 */ 3566 3567 if (SCTP_CID_COOKIE_ACK == ch->type) 3568 ootb_cookie_ack = 1; 3569 3570 if (SCTP_CID_ERROR == ch->type) { 3571 sctp_walk_errors(err, ch) { 3572 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3573 ootb_cookie_ack = 1; 3574 break; 3575 } 3576 } 3577 } 3578 3579 ch = (struct sctp_chunkhdr *)ch_end; 3580 } while (ch_end < skb_tail_pointer(skb)); 3581 3582 if (ootb_shut_ack) 3583 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3584 else if (ootb_cookie_ack) 3585 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3586 else 3587 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3588 } 3589 3590 /* 3591 * Handle an "Out of the blue" SHUTDOWN ACK. 3592 * 3593 * Section: 8.4 5, sctpimpguide 2.41. 3594 * 3595 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3596 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3597 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3598 * packet must fill in the Verification Tag field of the outbound 3599 * packet with the Verification Tag received in the SHUTDOWN ACK and 3600 * set the T-bit in the Chunk Flags to indicate that the Verification 3601 * Tag is reflected. 3602 * 3603 * Inputs 3604 * (endpoint, asoc, type, arg, commands) 3605 * 3606 * Outputs 3607 * (enum sctp_disposition) 3608 * 3609 * The return value is the disposition of the chunk. 3610 */ 3611 static enum sctp_disposition sctp_sf_shut_8_4_5( 3612 struct net *net, 3613 const struct sctp_endpoint *ep, 3614 const struct sctp_association *asoc, 3615 const union sctp_subtype type, 3616 void *arg, 3617 struct sctp_cmd_seq *commands) 3618 { 3619 struct sctp_packet *packet = NULL; 3620 struct sctp_chunk *chunk = arg; 3621 struct sctp_chunk *shut; 3622 3623 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3624 if (!packet) 3625 return SCTP_DISPOSITION_NOMEM; 3626 3627 /* Make an SHUTDOWN_COMPLETE. 3628 * The T bit will be set if the asoc is NULL. 3629 */ 3630 shut = sctp_make_shutdown_complete(asoc, chunk); 3631 if (!shut) { 3632 sctp_ootb_pkt_free(packet); 3633 return SCTP_DISPOSITION_NOMEM; 3634 } 3635 3636 /* Reflect vtag if T-Bit is set */ 3637 if (sctp_test_T_bit(shut)) 3638 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3639 3640 /* Set the skb to the belonging sock for accounting. */ 3641 shut->skb->sk = ep->base.sk; 3642 3643 sctp_packet_append_chunk(packet, shut); 3644 3645 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3646 SCTP_PACKET(packet)); 3647 3648 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3649 3650 /* If the chunk length is invalid, we don't want to process 3651 * the reset of the packet. 3652 */ 3653 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3654 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3655 3656 /* We need to discard the rest of the packet to prevent 3657 * potential bomming attacks from additional bundled chunks. 3658 * This is documented in SCTP Threats ID. 3659 */ 3660 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3661 } 3662 3663 /* 3664 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3665 * 3666 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3667 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3668 * procedures in section 8.4 SHOULD be followed, in other words it 3669 * should be treated as an Out Of The Blue packet. 3670 * [This means that we do NOT check the Verification Tag on these 3671 * chunks. --piggy ] 3672 * 3673 */ 3674 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3675 const struct sctp_endpoint *ep, 3676 const struct sctp_association *asoc, 3677 const union sctp_subtype type, 3678 void *arg, 3679 struct sctp_cmd_seq *commands) 3680 { 3681 struct sctp_chunk *chunk = arg; 3682 3683 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3684 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3685 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3686 commands); 3687 3688 /* Although we do have an association in this case, it corresponds 3689 * to a restarted association. So the packet is treated as an OOTB 3690 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3691 * called with a NULL association. 3692 */ 3693 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3694 3695 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3696 } 3697 3698 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3699 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3700 const struct sctp_endpoint *ep, 3701 const struct sctp_association *asoc, 3702 const union sctp_subtype type, 3703 void *arg, 3704 struct sctp_cmd_seq *commands) 3705 { 3706 struct sctp_paramhdr *err_param = NULL; 3707 struct sctp_chunk *asconf_ack = NULL; 3708 struct sctp_chunk *chunk = arg; 3709 struct sctp_addiphdr *hdr; 3710 __u32 serial; 3711 3712 if (!sctp_vtag_verify(chunk, asoc)) { 3713 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3714 SCTP_NULL()); 3715 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3716 } 3717 3718 /* ADD-IP: Section 4.1.1 3719 * This chunk MUST be sent in an authenticated way by using 3720 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3721 * is received unauthenticated it MUST be silently discarded as 3722 * described in [I-D.ietf-tsvwg-sctp-auth]. 3723 */ 3724 if (!net->sctp.addip_noauth && !chunk->auth) 3725 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3726 commands); 3727 3728 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3729 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3730 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3731 commands); 3732 3733 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3734 serial = ntohl(hdr->serial); 3735 3736 /* Verify the ASCONF chunk before processing it. */ 3737 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3738 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3739 (void *)err_param, commands); 3740 3741 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3742 * the endpoint stored in a new association variable 3743 * 'Peer-Serial-Number'. 3744 */ 3745 if (serial == asoc->peer.addip_serial + 1) { 3746 /* If this is the first instance of ASCONF in the packet, 3747 * we can clean our old ASCONF-ACKs. 3748 */ 3749 if (!chunk->has_asconf) 3750 sctp_assoc_clean_asconf_ack_cache(asoc); 3751 3752 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3753 * expected, process the ASCONF as described below and after 3754 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3755 * the response packet and cache a copy of it (in the event it 3756 * later needs to be retransmitted). 3757 * 3758 * Essentially, do V1-V5. 3759 */ 3760 asconf_ack = sctp_process_asconf((struct sctp_association *) 3761 asoc, chunk); 3762 if (!asconf_ack) 3763 return SCTP_DISPOSITION_NOMEM; 3764 } else if (serial < asoc->peer.addip_serial + 1) { 3765 /* ADDIP 5.2 E2) 3766 * If the value found in the Sequence Number is less than the 3767 * ('Peer- Sequence-Number' + 1), simply skip to the next 3768 * ASCONF, and include in the outbound response packet 3769 * any previously cached ASCONF-ACK response that was 3770 * sent and saved that matches the Sequence Number of the 3771 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3772 * Chunk exists. This will occur when an older ASCONF 3773 * arrives out of order. In such a case, the receiver 3774 * should skip the ASCONF Chunk and not include ASCONF-ACK 3775 * Chunk for that chunk. 3776 */ 3777 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3778 if (!asconf_ack) 3779 return SCTP_DISPOSITION_DISCARD; 3780 3781 /* Reset the transport so that we select the correct one 3782 * this time around. This is to make sure that we don't 3783 * accidentally use a stale transport that's been removed. 3784 */ 3785 asconf_ack->transport = NULL; 3786 } else { 3787 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3788 * it must be either a stale packet or from an attacker. 3789 */ 3790 return SCTP_DISPOSITION_DISCARD; 3791 } 3792 3793 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3794 * containing the ASCONF-ACK Chunks MUST be the source address of 3795 * the SCTP packet that held the ASCONF Chunks. 3796 * 3797 * To do this properly, we'll set the destination address of the chunk 3798 * and at the transmit time, will try look up the transport to use. 3799 * Since ASCONFs may be bundled, the correct transport may not be 3800 * created until we process the entire packet, thus this workaround. 3801 */ 3802 asconf_ack->dest = chunk->source; 3803 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3804 if (asoc->new_transport) { 3805 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3806 ((struct sctp_association *)asoc)->new_transport = NULL; 3807 } 3808 3809 return SCTP_DISPOSITION_CONSUME; 3810 } 3811 3812 /* 3813 * ADDIP Section 4.3 General rules for address manipulation 3814 * When building TLV parameters for the ASCONF Chunk that will add or 3815 * delete IP addresses the D0 to D13 rules should be applied: 3816 */ 3817 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 3818 const struct sctp_endpoint *ep, 3819 const struct sctp_association *asoc, 3820 const union sctp_subtype type, 3821 void *arg, 3822 struct sctp_cmd_seq *commands) 3823 { 3824 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3825 struct sctp_paramhdr *err_param = NULL; 3826 struct sctp_chunk *asconf_ack = arg; 3827 struct sctp_addiphdr *addip_hdr; 3828 __u32 sent_serial, rcvd_serial; 3829 struct sctp_chunk *abort; 3830 3831 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3832 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3833 SCTP_NULL()); 3834 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3835 } 3836 3837 /* ADD-IP, Section 4.1.2: 3838 * This chunk MUST be sent in an authenticated way by using 3839 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3840 * is received unauthenticated it MUST be silently discarded as 3841 * described in [I-D.ietf-tsvwg-sctp-auth]. 3842 */ 3843 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3844 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3845 commands); 3846 3847 /* Make sure that the ADDIP chunk has a valid length. */ 3848 if (!sctp_chunk_length_valid(asconf_ack, 3849 sizeof(struct sctp_addip_chunk))) 3850 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3851 commands); 3852 3853 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 3854 rcvd_serial = ntohl(addip_hdr->serial); 3855 3856 /* Verify the ASCONF-ACK chunk before processing it. */ 3857 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3858 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3859 (void *)err_param, commands); 3860 3861 if (last_asconf) { 3862 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr; 3863 sent_serial = ntohl(addip_hdr->serial); 3864 } else { 3865 sent_serial = asoc->addip_serial - 1; 3866 } 3867 3868 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3869 * equal to the next serial number to be used but no ASCONF chunk is 3870 * outstanding the endpoint MUST ABORT the association. Note that a 3871 * sequence number is greater than if it is no more than 2^^31-1 3872 * larger than the current sequence number (using serial arithmetic). 3873 */ 3874 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3875 !(asoc->addip_last_asconf)) { 3876 abort = sctp_make_abort(asoc, asconf_ack, 3877 sizeof(struct sctp_errhdr)); 3878 if (abort) { 3879 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3880 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3881 SCTP_CHUNK(abort)); 3882 } 3883 /* We are going to ABORT, so we might as well stop 3884 * processing the rest of the chunks in the packet. 3885 */ 3886 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3887 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3888 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3889 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3890 SCTP_ERROR(ECONNABORTED)); 3891 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3892 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3893 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3894 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3895 return SCTP_DISPOSITION_ABORT; 3896 } 3897 3898 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3899 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3900 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3901 3902 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3903 asconf_ack)) { 3904 /* Successfully processed ASCONF_ACK. We can 3905 * release the next asconf if we have one. 3906 */ 3907 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3908 SCTP_NULL()); 3909 return SCTP_DISPOSITION_CONSUME; 3910 } 3911 3912 abort = sctp_make_abort(asoc, asconf_ack, 3913 sizeof(struct sctp_errhdr)); 3914 if (abort) { 3915 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3916 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3917 SCTP_CHUNK(abort)); 3918 } 3919 /* We are going to ABORT, so we might as well stop 3920 * processing the rest of the chunks in the packet. 3921 */ 3922 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3923 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3924 SCTP_ERROR(ECONNABORTED)); 3925 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3926 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3927 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3928 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3929 return SCTP_DISPOSITION_ABORT; 3930 } 3931 3932 return SCTP_DISPOSITION_DISCARD; 3933 } 3934 3935 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 3936 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 3937 const struct sctp_endpoint *ep, 3938 const struct sctp_association *asoc, 3939 const union sctp_subtype type, 3940 void *arg, 3941 struct sctp_cmd_seq *commands) 3942 { 3943 struct sctp_paramhdr *err_param = NULL; 3944 struct sctp_chunk *chunk = arg; 3945 struct sctp_reconf_chunk *hdr; 3946 union sctp_params param; 3947 3948 if (!sctp_vtag_verify(chunk, asoc)) { 3949 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3950 SCTP_NULL()); 3951 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3952 } 3953 3954 /* Make sure that the RECONF chunk has a valid length. */ 3955 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 3956 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3957 commands); 3958 3959 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 3960 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3961 (void *)err_param, commands); 3962 3963 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 3964 sctp_walk_params(param, hdr, params) { 3965 struct sctp_chunk *reply = NULL; 3966 struct sctp_ulpevent *ev = NULL; 3967 3968 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 3969 reply = sctp_process_strreset_outreq( 3970 (struct sctp_association *)asoc, param, &ev); 3971 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 3972 reply = sctp_process_strreset_inreq( 3973 (struct sctp_association *)asoc, param, &ev); 3974 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 3975 reply = sctp_process_strreset_tsnreq( 3976 (struct sctp_association *)asoc, param, &ev); 3977 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 3978 reply = sctp_process_strreset_addstrm_out( 3979 (struct sctp_association *)asoc, param, &ev); 3980 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 3981 reply = sctp_process_strreset_addstrm_in( 3982 (struct sctp_association *)asoc, param, &ev); 3983 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 3984 reply = sctp_process_strreset_resp( 3985 (struct sctp_association *)asoc, param, &ev); 3986 3987 if (ev) 3988 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 3989 SCTP_ULPEVENT(ev)); 3990 3991 if (reply) 3992 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3993 SCTP_CHUNK(reply)); 3994 } 3995 3996 return SCTP_DISPOSITION_CONSUME; 3997 } 3998 3999 /* 4000 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4001 * 4002 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4003 * its cumulative TSN point to the value carried in the FORWARD TSN 4004 * chunk, and then MUST further advance its cumulative TSN point locally 4005 * if possible. 4006 * After the above processing, the data receiver MUST stop reporting any 4007 * missing TSNs earlier than or equal to the new cumulative TSN point. 4008 * 4009 * Verification Tag: 8.5 Verification Tag [Normal verification] 4010 * 4011 * The return value is the disposition of the chunk. 4012 */ 4013 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4014 const struct sctp_endpoint *ep, 4015 const struct sctp_association *asoc, 4016 const union sctp_subtype type, 4017 void *arg, 4018 struct sctp_cmd_seq *commands) 4019 { 4020 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4021 struct sctp_chunk *chunk = arg; 4022 __u16 len; 4023 __u32 tsn; 4024 4025 if (!sctp_vtag_verify(chunk, asoc)) { 4026 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4027 SCTP_NULL()); 4028 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4029 } 4030 4031 if (!asoc->peer.prsctp_capable) 4032 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4033 4034 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4035 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4036 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4037 commands); 4038 4039 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4040 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4041 len = ntohs(chunk->chunk_hdr->length); 4042 len -= sizeof(struct sctp_chunkhdr); 4043 skb_pull(chunk->skb, len); 4044 4045 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4046 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4047 4048 /* The TSN is too high--silently discard the chunk and count on it 4049 * getting retransmitted later. 4050 */ 4051 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4052 goto discard_noforce; 4053 4054 if (!asoc->stream.si->validate_ftsn(chunk)) 4055 goto discard_noforce; 4056 4057 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4058 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4059 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4060 SCTP_CHUNK(chunk)); 4061 4062 /* Count this as receiving DATA. */ 4063 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4064 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4065 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4066 } 4067 4068 /* FIXME: For now send a SACK, but DATA processing may 4069 * send another. 4070 */ 4071 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4072 4073 return SCTP_DISPOSITION_CONSUME; 4074 4075 discard_noforce: 4076 return SCTP_DISPOSITION_DISCARD; 4077 } 4078 4079 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4080 struct net *net, 4081 const struct sctp_endpoint *ep, 4082 const struct sctp_association *asoc, 4083 const union sctp_subtype type, 4084 void *arg, 4085 struct sctp_cmd_seq *commands) 4086 { 4087 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4088 struct sctp_chunk *chunk = arg; 4089 __u16 len; 4090 __u32 tsn; 4091 4092 if (!sctp_vtag_verify(chunk, asoc)) { 4093 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4094 SCTP_NULL()); 4095 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4096 } 4097 4098 if (!asoc->peer.prsctp_capable) 4099 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4100 4101 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4102 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4103 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4104 commands); 4105 4106 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4107 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4108 len = ntohs(chunk->chunk_hdr->length); 4109 len -= sizeof(struct sctp_chunkhdr); 4110 skb_pull(chunk->skb, len); 4111 4112 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4113 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4114 4115 /* The TSN is too high--silently discard the chunk and count on it 4116 * getting retransmitted later. 4117 */ 4118 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4119 goto gen_shutdown; 4120 4121 if (!asoc->stream.si->validate_ftsn(chunk)) 4122 goto gen_shutdown; 4123 4124 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4125 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4126 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4127 SCTP_CHUNK(chunk)); 4128 4129 /* Go a head and force a SACK, since we are shutting down. */ 4130 gen_shutdown: 4131 /* Implementor's Guide. 4132 * 4133 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4134 * respond to each received packet containing one or more DATA chunk(s) 4135 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4136 */ 4137 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4138 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4139 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4140 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4141 4142 return SCTP_DISPOSITION_CONSUME; 4143 } 4144 4145 /* 4146 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4147 * 4148 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4149 * Identifier field. If this algorithm was not specified by the 4150 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4151 * during association setup, the AUTH chunk and all chunks after it MUST 4152 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4153 * defined in Section 4.1. 4154 * 4155 * If an endpoint with no shared key receives a Shared Key Identifier 4156 * other than 0, it MUST silently discard all authenticated chunks. If 4157 * the endpoint has at least one endpoint pair shared key for the peer, 4158 * it MUST use the key specified by the Shared Key Identifier if a 4159 * key has been configured for that Shared Key Identifier. If no 4160 * endpoint pair shared key has been configured for that Shared Key 4161 * Identifier, all authenticated chunks MUST be silently discarded. 4162 * 4163 * Verification Tag: 8.5 Verification Tag [Normal verification] 4164 * 4165 * The return value is the disposition of the chunk. 4166 */ 4167 static enum sctp_ierror sctp_sf_authenticate( 4168 struct net *net, 4169 const struct sctp_endpoint *ep, 4170 const struct sctp_association *asoc, 4171 const union sctp_subtype type, 4172 struct sctp_chunk *chunk) 4173 { 4174 struct sctp_shared_key *sh_key = NULL; 4175 struct sctp_authhdr *auth_hdr; 4176 __u8 *save_digest, *digest; 4177 struct sctp_hmac *hmac; 4178 unsigned int sig_len; 4179 __u16 key_id; 4180 4181 /* Pull in the auth header, so we can do some more verification */ 4182 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4183 chunk->subh.auth_hdr = auth_hdr; 4184 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4185 4186 /* Make sure that we support the HMAC algorithm from the auth 4187 * chunk. 4188 */ 4189 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4190 return SCTP_IERROR_AUTH_BAD_HMAC; 4191 4192 /* Make sure that the provided shared key identifier has been 4193 * configured 4194 */ 4195 key_id = ntohs(auth_hdr->shkey_id); 4196 if (key_id != asoc->active_key_id) { 4197 sh_key = sctp_auth_get_shkey(asoc, key_id); 4198 if (!sh_key) 4199 return SCTP_IERROR_AUTH_BAD_KEYID; 4200 } 4201 4202 /* Make sure that the length of the signature matches what 4203 * we expect. 4204 */ 4205 sig_len = ntohs(chunk->chunk_hdr->length) - 4206 sizeof(struct sctp_auth_chunk); 4207 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4208 if (sig_len != hmac->hmac_len) 4209 return SCTP_IERROR_PROTO_VIOLATION; 4210 4211 /* Now that we've done validation checks, we can compute and 4212 * verify the hmac. The steps involved are: 4213 * 1. Save the digest from the chunk. 4214 * 2. Zero out the digest in the chunk. 4215 * 3. Compute the new digest 4216 * 4. Compare saved and new digests. 4217 */ 4218 digest = auth_hdr->hmac; 4219 skb_pull(chunk->skb, sig_len); 4220 4221 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4222 if (!save_digest) 4223 goto nomem; 4224 4225 memset(digest, 0, sig_len); 4226 4227 sctp_auth_calculate_hmac(asoc, chunk->skb, 4228 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4229 sh_key, GFP_ATOMIC); 4230 4231 /* Discard the packet if the digests do not match */ 4232 if (memcmp(save_digest, digest, sig_len)) { 4233 kfree(save_digest); 4234 return SCTP_IERROR_BAD_SIG; 4235 } 4236 4237 kfree(save_digest); 4238 chunk->auth = 1; 4239 4240 return SCTP_IERROR_NO_ERROR; 4241 nomem: 4242 return SCTP_IERROR_NOMEM; 4243 } 4244 4245 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4246 const struct sctp_endpoint *ep, 4247 const struct sctp_association *asoc, 4248 const union sctp_subtype type, 4249 void *arg, struct sctp_cmd_seq *commands) 4250 { 4251 struct sctp_chunk *chunk = arg; 4252 struct sctp_authhdr *auth_hdr; 4253 struct sctp_chunk *err_chunk; 4254 enum sctp_ierror error; 4255 4256 /* Make sure that the peer has AUTH capable */ 4257 if (!asoc->peer.auth_capable) 4258 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4259 4260 if (!sctp_vtag_verify(chunk, asoc)) { 4261 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4262 SCTP_NULL()); 4263 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4264 } 4265 4266 /* Make sure that the AUTH chunk has valid length. */ 4267 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4268 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4269 commands); 4270 4271 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4272 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4273 switch (error) { 4274 case SCTP_IERROR_AUTH_BAD_HMAC: 4275 /* Generate the ERROR chunk and discard the rest 4276 * of the packet 4277 */ 4278 err_chunk = sctp_make_op_error(asoc, chunk, 4279 SCTP_ERROR_UNSUP_HMAC, 4280 &auth_hdr->hmac_id, 4281 sizeof(__u16), 0); 4282 if (err_chunk) { 4283 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4284 SCTP_CHUNK(err_chunk)); 4285 } 4286 /* Fall Through */ 4287 case SCTP_IERROR_AUTH_BAD_KEYID: 4288 case SCTP_IERROR_BAD_SIG: 4289 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4290 4291 case SCTP_IERROR_PROTO_VIOLATION: 4292 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4293 commands); 4294 4295 case SCTP_IERROR_NOMEM: 4296 return SCTP_DISPOSITION_NOMEM; 4297 4298 default: /* Prevent gcc warnings */ 4299 break; 4300 } 4301 4302 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4303 struct sctp_ulpevent *ev; 4304 4305 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4306 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4307 4308 if (!ev) 4309 return -ENOMEM; 4310 4311 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4312 SCTP_ULPEVENT(ev)); 4313 } 4314 4315 return SCTP_DISPOSITION_CONSUME; 4316 } 4317 4318 /* 4319 * Process an unknown chunk. 4320 * 4321 * Section: 3.2. Also, 2.1 in the implementor's guide. 4322 * 4323 * Chunk Types are encoded such that the highest-order two bits specify 4324 * the action that must be taken if the processing endpoint does not 4325 * recognize the Chunk Type. 4326 * 4327 * 00 - Stop processing this SCTP packet and discard it, do not process 4328 * any further chunks within it. 4329 * 4330 * 01 - Stop processing this SCTP packet and discard it, do not process 4331 * any further chunks within it, and report the unrecognized 4332 * chunk in an 'Unrecognized Chunk Type'. 4333 * 4334 * 10 - Skip this chunk and continue processing. 4335 * 4336 * 11 - Skip this chunk and continue processing, but report in an ERROR 4337 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4338 * 4339 * The return value is the disposition of the chunk. 4340 */ 4341 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4342 const struct sctp_endpoint *ep, 4343 const struct sctp_association *asoc, 4344 const union sctp_subtype type, 4345 void *arg, 4346 struct sctp_cmd_seq *commands) 4347 { 4348 struct sctp_chunk *unk_chunk = arg; 4349 struct sctp_chunk *err_chunk; 4350 struct sctp_chunkhdr *hdr; 4351 4352 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4353 4354 if (!sctp_vtag_verify(unk_chunk, asoc)) 4355 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4356 4357 /* Make sure that the chunk has a valid length. 4358 * Since we don't know the chunk type, we use a general 4359 * chunkhdr structure to make a comparison. 4360 */ 4361 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4362 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4363 commands); 4364 4365 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4366 case SCTP_CID_ACTION_DISCARD: 4367 /* Discard the packet. */ 4368 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4369 case SCTP_CID_ACTION_DISCARD_ERR: 4370 /* Generate an ERROR chunk as response. */ 4371 hdr = unk_chunk->chunk_hdr; 4372 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4373 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4374 SCTP_PAD4(ntohs(hdr->length)), 4375 0); 4376 if (err_chunk) { 4377 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4378 SCTP_CHUNK(err_chunk)); 4379 } 4380 4381 /* Discard the packet. */ 4382 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4383 return SCTP_DISPOSITION_CONSUME; 4384 case SCTP_CID_ACTION_SKIP: 4385 /* Skip the chunk. */ 4386 return SCTP_DISPOSITION_DISCARD; 4387 case SCTP_CID_ACTION_SKIP_ERR: 4388 /* Generate an ERROR chunk as response. */ 4389 hdr = unk_chunk->chunk_hdr; 4390 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4391 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4392 SCTP_PAD4(ntohs(hdr->length)), 4393 0); 4394 if (err_chunk) { 4395 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4396 SCTP_CHUNK(err_chunk)); 4397 } 4398 /* Skip the chunk. */ 4399 return SCTP_DISPOSITION_CONSUME; 4400 default: 4401 break; 4402 } 4403 4404 return SCTP_DISPOSITION_DISCARD; 4405 } 4406 4407 /* 4408 * Discard the chunk. 4409 * 4410 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4411 * [Too numerous to mention...] 4412 * Verification Tag: No verification needed. 4413 * Inputs 4414 * (endpoint, asoc, chunk) 4415 * 4416 * Outputs 4417 * (asoc, reply_msg, msg_up, timers, counters) 4418 * 4419 * The return value is the disposition of the chunk. 4420 */ 4421 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4422 const struct sctp_endpoint *ep, 4423 const struct sctp_association *asoc, 4424 const union sctp_subtype type, 4425 void *arg, 4426 struct sctp_cmd_seq *commands) 4427 { 4428 struct sctp_chunk *chunk = arg; 4429 4430 /* Make sure that the chunk has a valid length. 4431 * Since we don't know the chunk type, we use a general 4432 * chunkhdr structure to make a comparison. 4433 */ 4434 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4435 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4436 commands); 4437 4438 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4439 4440 return SCTP_DISPOSITION_DISCARD; 4441 } 4442 4443 /* 4444 * Discard the whole packet. 4445 * 4446 * Section: 8.4 2) 4447 * 4448 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4449 * silently discard the OOTB packet and take no further action. 4450 * 4451 * Verification Tag: No verification necessary 4452 * 4453 * Inputs 4454 * (endpoint, asoc, chunk) 4455 * 4456 * Outputs 4457 * (asoc, reply_msg, msg_up, timers, counters) 4458 * 4459 * The return value is the disposition of the chunk. 4460 */ 4461 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4462 const struct sctp_endpoint *ep, 4463 const struct sctp_association *asoc, 4464 const union sctp_subtype type, 4465 void *arg, struct sctp_cmd_seq *commands) 4466 { 4467 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4468 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4469 4470 return SCTP_DISPOSITION_CONSUME; 4471 } 4472 4473 4474 /* 4475 * The other end is violating protocol. 4476 * 4477 * Section: Not specified 4478 * Verification Tag: Not specified 4479 * Inputs 4480 * (endpoint, asoc, chunk) 4481 * 4482 * Outputs 4483 * (asoc, reply_msg, msg_up, timers, counters) 4484 * 4485 * We simply tag the chunk as a violation. The state machine will log 4486 * the violation and continue. 4487 */ 4488 enum sctp_disposition sctp_sf_violation(struct net *net, 4489 const struct sctp_endpoint *ep, 4490 const struct sctp_association *asoc, 4491 const union sctp_subtype type, 4492 void *arg, 4493 struct sctp_cmd_seq *commands) 4494 { 4495 struct sctp_chunk *chunk = arg; 4496 4497 /* Make sure that the chunk has a valid length. */ 4498 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4499 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4500 commands); 4501 4502 return SCTP_DISPOSITION_VIOLATION; 4503 } 4504 4505 /* 4506 * Common function to handle a protocol violation. 4507 */ 4508 static enum sctp_disposition sctp_sf_abort_violation( 4509 struct net *net, 4510 const struct sctp_endpoint *ep, 4511 const struct sctp_association *asoc, 4512 void *arg, 4513 struct sctp_cmd_seq *commands, 4514 const __u8 *payload, 4515 const size_t paylen) 4516 { 4517 struct sctp_packet *packet = NULL; 4518 struct sctp_chunk *chunk = arg; 4519 struct sctp_chunk *abort = NULL; 4520 4521 /* SCTP-AUTH, Section 6.3: 4522 * It should be noted that if the receiver wants to tear 4523 * down an association in an authenticated way only, the 4524 * handling of malformed packets should not result in 4525 * tearing down the association. 4526 * 4527 * This means that if we only want to abort associations 4528 * in an authenticated way (i.e AUTH+ABORT), then we 4529 * can't destroy this association just because the packet 4530 * was malformed. 4531 */ 4532 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4533 goto discard; 4534 4535 /* Make the abort chunk. */ 4536 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4537 if (!abort) 4538 goto nomem; 4539 4540 if (asoc) { 4541 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4542 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4543 !asoc->peer.i.init_tag) { 4544 struct sctp_initack_chunk *initack; 4545 4546 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4547 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4548 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4549 else { 4550 unsigned int inittag; 4551 4552 inittag = ntohl(initack->init_hdr.init_tag); 4553 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4554 SCTP_U32(inittag)); 4555 } 4556 } 4557 4558 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4559 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4560 4561 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4562 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4563 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4564 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4565 SCTP_ERROR(ECONNREFUSED)); 4566 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4567 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4568 } else { 4569 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4570 SCTP_ERROR(ECONNABORTED)); 4571 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4572 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4573 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4574 } 4575 } else { 4576 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4577 4578 if (!packet) 4579 goto nomem_pkt; 4580 4581 if (sctp_test_T_bit(abort)) 4582 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4583 4584 abort->skb->sk = ep->base.sk; 4585 4586 sctp_packet_append_chunk(packet, abort); 4587 4588 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4589 SCTP_PACKET(packet)); 4590 4591 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4592 } 4593 4594 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4595 4596 discard: 4597 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4598 return SCTP_DISPOSITION_ABORT; 4599 4600 nomem_pkt: 4601 sctp_chunk_free(abort); 4602 nomem: 4603 return SCTP_DISPOSITION_NOMEM; 4604 } 4605 4606 /* 4607 * Handle a protocol violation when the chunk length is invalid. 4608 * "Invalid" length is identified as smaller than the minimal length a 4609 * given chunk can be. For example, a SACK chunk has invalid length 4610 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4611 * 4612 * We inform the other end by sending an ABORT with a Protocol Violation 4613 * error code. 4614 * 4615 * Section: Not specified 4616 * Verification Tag: Nothing to do 4617 * Inputs 4618 * (endpoint, asoc, chunk) 4619 * 4620 * Outputs 4621 * (reply_msg, msg_up, counters) 4622 * 4623 * Generate an ABORT chunk and terminate the association. 4624 */ 4625 static enum sctp_disposition sctp_sf_violation_chunklen( 4626 struct net *net, 4627 const struct sctp_endpoint *ep, 4628 const struct sctp_association *asoc, 4629 const union sctp_subtype type, 4630 void *arg, 4631 struct sctp_cmd_seq *commands) 4632 { 4633 static const char err_str[] = "The following chunk had invalid length:"; 4634 4635 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4636 sizeof(err_str)); 4637 } 4638 4639 /* 4640 * Handle a protocol violation when the parameter length is invalid. 4641 * If the length is smaller than the minimum length of a given parameter, 4642 * or accumulated length in multi parameters exceeds the end of the chunk, 4643 * the length is considered as invalid. 4644 */ 4645 static enum sctp_disposition sctp_sf_violation_paramlen( 4646 struct net *net, 4647 const struct sctp_endpoint *ep, 4648 const struct sctp_association *asoc, 4649 const union sctp_subtype type, 4650 void *arg, void *ext, 4651 struct sctp_cmd_seq *commands) 4652 { 4653 struct sctp_paramhdr *param = ext; 4654 struct sctp_chunk *abort = NULL; 4655 struct sctp_chunk *chunk = arg; 4656 4657 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4658 goto discard; 4659 4660 /* Make the abort chunk. */ 4661 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4662 if (!abort) 4663 goto nomem; 4664 4665 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4666 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4667 4668 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4669 SCTP_ERROR(ECONNABORTED)); 4670 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4671 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4672 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4673 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4674 4675 discard: 4676 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4677 return SCTP_DISPOSITION_ABORT; 4678 nomem: 4679 return SCTP_DISPOSITION_NOMEM; 4680 } 4681 4682 /* Handle a protocol violation when the peer trying to advance the 4683 * cumulative tsn ack to a point beyond the max tsn currently sent. 4684 * 4685 * We inform the other end by sending an ABORT with a Protocol Violation 4686 * error code. 4687 */ 4688 static enum sctp_disposition sctp_sf_violation_ctsn( 4689 struct net *net, 4690 const struct sctp_endpoint *ep, 4691 const struct sctp_association *asoc, 4692 const union sctp_subtype type, 4693 void *arg, 4694 struct sctp_cmd_seq *commands) 4695 { 4696 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4697 4698 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4699 sizeof(err_str)); 4700 } 4701 4702 /* Handle protocol violation of an invalid chunk bundling. For example, 4703 * when we have an association and we receive bundled INIT-ACK, or 4704 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4705 * statement from the specs. Additionally, there might be an attacker 4706 * on the path and we may not want to continue this communication. 4707 */ 4708 static enum sctp_disposition sctp_sf_violation_chunk( 4709 struct net *net, 4710 const struct sctp_endpoint *ep, 4711 const struct sctp_association *asoc, 4712 const union sctp_subtype type, 4713 void *arg, 4714 struct sctp_cmd_seq *commands) 4715 { 4716 static const char err_str[] = "The following chunk violates protocol:"; 4717 4718 if (!asoc) 4719 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4720 4721 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4722 sizeof(err_str)); 4723 } 4724 /*************************************************************************** 4725 * These are the state functions for handling primitive (Section 10) events. 4726 ***************************************************************************/ 4727 /* 4728 * sctp_sf_do_prm_asoc 4729 * 4730 * Section: 10.1 ULP-to-SCTP 4731 * B) Associate 4732 * 4733 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4734 * outbound stream count) 4735 * -> association id [,destination transport addr list] [,outbound stream 4736 * count] 4737 * 4738 * This primitive allows the upper layer to initiate an association to a 4739 * specific peer endpoint. 4740 * 4741 * The peer endpoint shall be specified by one of the transport addresses 4742 * which defines the endpoint (see Section 1.4). If the local SCTP 4743 * instance has not been initialized, the ASSOCIATE is considered an 4744 * error. 4745 * [This is not relevant for the kernel implementation since we do all 4746 * initialization at boot time. It we hadn't initialized we wouldn't 4747 * get anywhere near this code.] 4748 * 4749 * An association id, which is a local handle to the SCTP association, 4750 * will be returned on successful establishment of the association. If 4751 * SCTP is not able to open an SCTP association with the peer endpoint, 4752 * an error is returned. 4753 * [In the kernel implementation, the struct sctp_association needs to 4754 * be created BEFORE causing this primitive to run.] 4755 * 4756 * Other association parameters may be returned, including the 4757 * complete destination transport addresses of the peer as well as the 4758 * outbound stream count of the local endpoint. One of the transport 4759 * address from the returned destination addresses will be selected by 4760 * the local endpoint as default primary path for sending SCTP packets 4761 * to this peer. The returned "destination transport addr list" can 4762 * be used by the ULP to change the default primary path or to force 4763 * sending a packet to a specific transport address. [All of this 4764 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4765 * function.] 4766 * 4767 * Mandatory attributes: 4768 * 4769 * o local SCTP instance name - obtained from the INITIALIZE operation. 4770 * [This is the argument asoc.] 4771 * o destination transport addr - specified as one of the transport 4772 * addresses of the peer endpoint with which the association is to be 4773 * established. 4774 * [This is asoc->peer.active_path.] 4775 * o outbound stream count - the number of outbound streams the ULP 4776 * would like to open towards this peer endpoint. 4777 * [BUG: This is not currently implemented.] 4778 * Optional attributes: 4779 * 4780 * None. 4781 * 4782 * The return value is a disposition. 4783 */ 4784 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4785 const struct sctp_endpoint *ep, 4786 const struct sctp_association *asoc, 4787 const union sctp_subtype type, 4788 void *arg, 4789 struct sctp_cmd_seq *commands) 4790 { 4791 struct sctp_association *my_asoc; 4792 struct sctp_chunk *repl; 4793 4794 /* The comment below says that we enter COOKIE-WAIT AFTER 4795 * sending the INIT, but that doesn't actually work in our 4796 * implementation... 4797 */ 4798 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4799 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4800 4801 /* RFC 2960 5.1 Normal Establishment of an Association 4802 * 4803 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4804 * must provide its Verification Tag (Tag_A) in the Initiate 4805 * Tag field. Tag_A SHOULD be a random number in the range of 4806 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4807 */ 4808 4809 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4810 if (!repl) 4811 goto nomem; 4812 4813 /* Choose transport for INIT. */ 4814 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4815 SCTP_CHUNK(repl)); 4816 4817 /* Cast away the const modifier, as we want to just 4818 * rerun it through as a sideffect. 4819 */ 4820 my_asoc = (struct sctp_association *)asoc; 4821 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4822 4823 /* After sending the INIT, "A" starts the T1-init timer and 4824 * enters the COOKIE-WAIT state. 4825 */ 4826 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4827 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4828 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4829 return SCTP_DISPOSITION_CONSUME; 4830 4831 nomem: 4832 return SCTP_DISPOSITION_NOMEM; 4833 } 4834 4835 /* 4836 * Process the SEND primitive. 4837 * 4838 * Section: 10.1 ULP-to-SCTP 4839 * E) Send 4840 * 4841 * Format: SEND(association id, buffer address, byte count [,context] 4842 * [,stream id] [,life time] [,destination transport address] 4843 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4844 * -> result 4845 * 4846 * This is the main method to send user data via SCTP. 4847 * 4848 * Mandatory attributes: 4849 * 4850 * o association id - local handle to the SCTP association 4851 * 4852 * o buffer address - the location where the user message to be 4853 * transmitted is stored; 4854 * 4855 * o byte count - The size of the user data in number of bytes; 4856 * 4857 * Optional attributes: 4858 * 4859 * o context - an optional 32 bit integer that will be carried in the 4860 * sending failure notification to the ULP if the transportation of 4861 * this User Message fails. 4862 * 4863 * o stream id - to indicate which stream to send the data on. If not 4864 * specified, stream 0 will be used. 4865 * 4866 * o life time - specifies the life time of the user data. The user data 4867 * will not be sent by SCTP after the life time expires. This 4868 * parameter can be used to avoid efforts to transmit stale 4869 * user messages. SCTP notifies the ULP if the data cannot be 4870 * initiated to transport (i.e. sent to the destination via SCTP's 4871 * send primitive) within the life time variable. However, the 4872 * user data will be transmitted if SCTP has attempted to transmit a 4873 * chunk before the life time expired. 4874 * 4875 * o destination transport address - specified as one of the destination 4876 * transport addresses of the peer endpoint to which this packet 4877 * should be sent. Whenever possible, SCTP should use this destination 4878 * transport address for sending the packets, instead of the current 4879 * primary path. 4880 * 4881 * o unorder flag - this flag, if present, indicates that the user 4882 * would like the data delivered in an unordered fashion to the peer 4883 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4884 * message). 4885 * 4886 * o no-bundle flag - instructs SCTP not to bundle this user data with 4887 * other outbound DATA chunks. SCTP MAY still bundle even when 4888 * this flag is present, when faced with network congestion. 4889 * 4890 * o payload protocol-id - A 32 bit unsigned integer that is to be 4891 * passed to the peer indicating the type of payload protocol data 4892 * being transmitted. This value is passed as opaque data by SCTP. 4893 * 4894 * The return value is the disposition. 4895 */ 4896 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 4897 const struct sctp_endpoint *ep, 4898 const struct sctp_association *asoc, 4899 const union sctp_subtype type, 4900 void *arg, 4901 struct sctp_cmd_seq *commands) 4902 { 4903 struct sctp_datamsg *msg = arg; 4904 4905 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4906 return SCTP_DISPOSITION_CONSUME; 4907 } 4908 4909 /* 4910 * Process the SHUTDOWN primitive. 4911 * 4912 * Section: 10.1: 4913 * C) Shutdown 4914 * 4915 * Format: SHUTDOWN(association id) 4916 * -> result 4917 * 4918 * Gracefully closes an association. Any locally queued user data 4919 * will be delivered to the peer. The association will be terminated only 4920 * after the peer acknowledges all the SCTP packets sent. A success code 4921 * will be returned on successful termination of the association. If 4922 * attempting to terminate the association results in a failure, an error 4923 * code shall be returned. 4924 * 4925 * Mandatory attributes: 4926 * 4927 * o association id - local handle to the SCTP association 4928 * 4929 * Optional attributes: 4930 * 4931 * None. 4932 * 4933 * The return value is the disposition. 4934 */ 4935 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 4936 struct net *net, 4937 const struct sctp_endpoint *ep, 4938 const struct sctp_association *asoc, 4939 const union sctp_subtype type, 4940 void *arg, 4941 struct sctp_cmd_seq *commands) 4942 { 4943 enum sctp_disposition disposition; 4944 4945 /* From 9.2 Shutdown of an Association 4946 * Upon receipt of the SHUTDOWN primitive from its upper 4947 * layer, the endpoint enters SHUTDOWN-PENDING state and 4948 * remains there until all outstanding data has been 4949 * acknowledged by its peer. The endpoint accepts no new data 4950 * from its upper layer, but retransmits data to the far end 4951 * if necessary to fill gaps. 4952 */ 4953 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4954 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4955 4956 disposition = SCTP_DISPOSITION_CONSUME; 4957 if (sctp_outq_is_empty(&asoc->outqueue)) { 4958 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4959 arg, commands); 4960 } 4961 4962 return disposition; 4963 } 4964 4965 /* 4966 * Process the ABORT primitive. 4967 * 4968 * Section: 10.1: 4969 * C) Abort 4970 * 4971 * Format: Abort(association id [, cause code]) 4972 * -> result 4973 * 4974 * Ungracefully closes an association. Any locally queued user data 4975 * will be discarded and an ABORT chunk is sent to the peer. A success code 4976 * will be returned on successful abortion of the association. If 4977 * attempting to abort the association results in a failure, an error 4978 * code shall be returned. 4979 * 4980 * Mandatory attributes: 4981 * 4982 * o association id - local handle to the SCTP association 4983 * 4984 * Optional attributes: 4985 * 4986 * o cause code - reason of the abort to be passed to the peer 4987 * 4988 * None. 4989 * 4990 * The return value is the disposition. 4991 */ 4992 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 4993 struct net *net, 4994 const struct sctp_endpoint *ep, 4995 const struct sctp_association *asoc, 4996 const union sctp_subtype type, 4997 void *arg, 4998 struct sctp_cmd_seq *commands) 4999 { 5000 /* From 9.1 Abort of an Association 5001 * Upon receipt of the ABORT primitive from its upper 5002 * layer, the endpoint enters CLOSED state and 5003 * discard all outstanding data has been 5004 * acknowledged by its peer. The endpoint accepts no new data 5005 * from its upper layer, but retransmits data to the far end 5006 * if necessary to fill gaps. 5007 */ 5008 struct sctp_chunk *abort = arg; 5009 5010 if (abort) 5011 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5012 5013 /* Even if we can't send the ABORT due to low memory delete the 5014 * TCB. This is a departure from our typical NOMEM handling. 5015 */ 5016 5017 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5018 SCTP_ERROR(ECONNABORTED)); 5019 /* Delete the established association. */ 5020 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5021 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5022 5023 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5024 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5025 5026 return SCTP_DISPOSITION_ABORT; 5027 } 5028 5029 /* We tried an illegal operation on an association which is closed. */ 5030 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5031 const struct sctp_endpoint *ep, 5032 const struct sctp_association *asoc, 5033 const union sctp_subtype type, 5034 void *arg, 5035 struct sctp_cmd_seq *commands) 5036 { 5037 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5038 return SCTP_DISPOSITION_CONSUME; 5039 } 5040 5041 /* We tried an illegal operation on an association which is shutting 5042 * down. 5043 */ 5044 enum sctp_disposition sctp_sf_error_shutdown( 5045 struct net *net, 5046 const struct sctp_endpoint *ep, 5047 const struct sctp_association *asoc, 5048 const union sctp_subtype type, 5049 void *arg, 5050 struct sctp_cmd_seq *commands) 5051 { 5052 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5053 SCTP_ERROR(-ESHUTDOWN)); 5054 return SCTP_DISPOSITION_CONSUME; 5055 } 5056 5057 /* 5058 * sctp_cookie_wait_prm_shutdown 5059 * 5060 * Section: 4 Note: 2 5061 * Verification Tag: 5062 * Inputs 5063 * (endpoint, asoc) 5064 * 5065 * The RFC does not explicitly address this issue, but is the route through the 5066 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5067 * 5068 * Outputs 5069 * (timers) 5070 */ 5071 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5072 struct net *net, 5073 const struct sctp_endpoint *ep, 5074 const struct sctp_association *asoc, 5075 const union sctp_subtype type, 5076 void *arg, 5077 struct sctp_cmd_seq *commands) 5078 { 5079 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5080 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5081 5082 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5083 SCTP_STATE(SCTP_STATE_CLOSED)); 5084 5085 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5086 5087 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5088 5089 return SCTP_DISPOSITION_DELETE_TCB; 5090 } 5091 5092 /* 5093 * sctp_cookie_echoed_prm_shutdown 5094 * 5095 * Section: 4 Note: 2 5096 * Verification Tag: 5097 * Inputs 5098 * (endpoint, asoc) 5099 * 5100 * The RFC does not explcitly address this issue, but is the route through the 5101 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5102 * 5103 * Outputs 5104 * (timers) 5105 */ 5106 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5107 struct net *net, 5108 const struct sctp_endpoint *ep, 5109 const struct sctp_association *asoc, 5110 const union sctp_subtype type, 5111 void *arg, 5112 struct sctp_cmd_seq *commands) 5113 { 5114 /* There is a single T1 timer, so we should be able to use 5115 * common function with the COOKIE-WAIT state. 5116 */ 5117 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5118 } 5119 5120 /* 5121 * sctp_sf_cookie_wait_prm_abort 5122 * 5123 * Section: 4 Note: 2 5124 * Verification Tag: 5125 * Inputs 5126 * (endpoint, asoc) 5127 * 5128 * The RFC does not explicitly address this issue, but is the route through the 5129 * state table when someone issues an abort while in COOKIE_WAIT state. 5130 * 5131 * Outputs 5132 * (timers) 5133 */ 5134 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5135 struct net *net, 5136 const struct sctp_endpoint *ep, 5137 const struct sctp_association *asoc, 5138 const union sctp_subtype type, 5139 void *arg, 5140 struct sctp_cmd_seq *commands) 5141 { 5142 struct sctp_chunk *abort = arg; 5143 5144 /* Stop T1-init timer */ 5145 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5146 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5147 5148 if (abort) 5149 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5150 5151 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5152 SCTP_STATE(SCTP_STATE_CLOSED)); 5153 5154 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5155 5156 /* Even if we can't send the ABORT due to low memory delete the 5157 * TCB. This is a departure from our typical NOMEM handling. 5158 */ 5159 5160 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5161 SCTP_ERROR(ECONNREFUSED)); 5162 /* Delete the established association. */ 5163 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5164 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5165 5166 return SCTP_DISPOSITION_ABORT; 5167 } 5168 5169 /* 5170 * sctp_sf_cookie_echoed_prm_abort 5171 * 5172 * Section: 4 Note: 3 5173 * Verification Tag: 5174 * Inputs 5175 * (endpoint, asoc) 5176 * 5177 * The RFC does not explcitly address this issue, but is the route through the 5178 * state table when someone issues an abort while in COOKIE_ECHOED state. 5179 * 5180 * Outputs 5181 * (timers) 5182 */ 5183 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5184 struct net *net, 5185 const struct sctp_endpoint *ep, 5186 const struct sctp_association *asoc, 5187 const union sctp_subtype type, 5188 void *arg, 5189 struct sctp_cmd_seq *commands) 5190 { 5191 /* There is a single T1 timer, so we should be able to use 5192 * common function with the COOKIE-WAIT state. 5193 */ 5194 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5195 } 5196 5197 /* 5198 * sctp_sf_shutdown_pending_prm_abort 5199 * 5200 * Inputs 5201 * (endpoint, asoc) 5202 * 5203 * The RFC does not explicitly address this issue, but is the route through the 5204 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5205 * 5206 * Outputs 5207 * (timers) 5208 */ 5209 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5210 struct net *net, 5211 const struct sctp_endpoint *ep, 5212 const struct sctp_association *asoc, 5213 const union sctp_subtype type, 5214 void *arg, 5215 struct sctp_cmd_seq *commands) 5216 { 5217 /* Stop the T5-shutdown guard timer. */ 5218 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5219 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5220 5221 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5222 } 5223 5224 /* 5225 * sctp_sf_shutdown_sent_prm_abort 5226 * 5227 * Inputs 5228 * (endpoint, asoc) 5229 * 5230 * The RFC does not explicitly address this issue, but is the route through the 5231 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5232 * 5233 * Outputs 5234 * (timers) 5235 */ 5236 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5237 struct net *net, 5238 const struct sctp_endpoint *ep, 5239 const struct sctp_association *asoc, 5240 const union sctp_subtype type, 5241 void *arg, 5242 struct sctp_cmd_seq *commands) 5243 { 5244 /* Stop the T2-shutdown timer. */ 5245 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5246 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5247 5248 /* Stop the T5-shutdown guard timer. */ 5249 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5250 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5251 5252 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5253 } 5254 5255 /* 5256 * sctp_sf_cookie_echoed_prm_abort 5257 * 5258 * Inputs 5259 * (endpoint, asoc) 5260 * 5261 * The RFC does not explcitly address this issue, but is the route through the 5262 * state table when someone issues an abort while in COOKIE_ECHOED state. 5263 * 5264 * Outputs 5265 * (timers) 5266 */ 5267 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5268 struct net *net, 5269 const struct sctp_endpoint *ep, 5270 const struct sctp_association *asoc, 5271 const union sctp_subtype type, 5272 void *arg, 5273 struct sctp_cmd_seq *commands) 5274 { 5275 /* The same T2 timer, so we should be able to use 5276 * common function with the SHUTDOWN-SENT state. 5277 */ 5278 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5279 } 5280 5281 /* 5282 * Process the REQUESTHEARTBEAT primitive 5283 * 5284 * 10.1 ULP-to-SCTP 5285 * J) Request Heartbeat 5286 * 5287 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5288 * 5289 * -> result 5290 * 5291 * Instructs the local endpoint to perform a HeartBeat on the specified 5292 * destination transport address of the given association. The returned 5293 * result should indicate whether the transmission of the HEARTBEAT 5294 * chunk to the destination address is successful. 5295 * 5296 * Mandatory attributes: 5297 * 5298 * o association id - local handle to the SCTP association 5299 * 5300 * o destination transport address - the transport address of the 5301 * association on which a heartbeat should be issued. 5302 */ 5303 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5304 struct net *net, 5305 const struct sctp_endpoint *ep, 5306 const struct sctp_association *asoc, 5307 const union sctp_subtype type, 5308 void *arg, 5309 struct sctp_cmd_seq *commands) 5310 { 5311 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5312 (struct sctp_transport *)arg, commands)) 5313 return SCTP_DISPOSITION_NOMEM; 5314 5315 /* 5316 * RFC 2960 (bis), section 8.3 5317 * 5318 * D) Request an on-demand HEARTBEAT on a specific destination 5319 * transport address of a given association. 5320 * 5321 * The endpoint should increment the respective error counter of 5322 * the destination transport address each time a HEARTBEAT is sent 5323 * to that address and not acknowledged within one RTO. 5324 * 5325 */ 5326 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5327 SCTP_TRANSPORT(arg)); 5328 return SCTP_DISPOSITION_CONSUME; 5329 } 5330 5331 /* 5332 * ADDIP Section 4.1 ASCONF Chunk Procedures 5333 * When an endpoint has an ASCONF signaled change to be sent to the 5334 * remote endpoint it should do A1 to A9 5335 */ 5336 enum sctp_disposition sctp_sf_do_prm_asconf(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_chunk *chunk = arg; 5344 5345 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5346 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5347 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5348 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5349 return SCTP_DISPOSITION_CONSUME; 5350 } 5351 5352 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5353 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5354 const struct sctp_endpoint *ep, 5355 const struct sctp_association *asoc, 5356 const union sctp_subtype type, 5357 void *arg, 5358 struct sctp_cmd_seq *commands) 5359 { 5360 struct sctp_chunk *chunk = arg; 5361 5362 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5363 return SCTP_DISPOSITION_CONSUME; 5364 } 5365 5366 /* 5367 * Ignore the primitive event 5368 * 5369 * The return value is the disposition of the primitive. 5370 */ 5371 enum sctp_disposition sctp_sf_ignore_primitive( 5372 struct net *net, 5373 const struct sctp_endpoint *ep, 5374 const struct sctp_association *asoc, 5375 const union sctp_subtype type, 5376 void *arg, 5377 struct sctp_cmd_seq *commands) 5378 { 5379 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5380 type.primitive); 5381 5382 return SCTP_DISPOSITION_DISCARD; 5383 } 5384 5385 /*************************************************************************** 5386 * These are the state functions for the OTHER events. 5387 ***************************************************************************/ 5388 5389 /* 5390 * When the SCTP stack has no more user data to send or retransmit, this 5391 * notification is given to the user. Also, at the time when a user app 5392 * subscribes to this event, if there is no data to be sent or 5393 * retransmit, the stack will immediately send up this notification. 5394 */ 5395 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5396 struct net *net, 5397 const struct sctp_endpoint *ep, 5398 const struct sctp_association *asoc, 5399 const union sctp_subtype type, 5400 void *arg, 5401 struct sctp_cmd_seq *commands) 5402 { 5403 struct sctp_ulpevent *event; 5404 5405 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5406 if (!event) 5407 return SCTP_DISPOSITION_NOMEM; 5408 5409 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5410 5411 return SCTP_DISPOSITION_CONSUME; 5412 } 5413 5414 /* 5415 * Start the shutdown negotiation. 5416 * 5417 * From Section 9.2: 5418 * Once all its outstanding data has been acknowledged, the endpoint 5419 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5420 * TSN Ack field the last sequential TSN it has received from the peer. 5421 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5422 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5423 * with the updated last sequential TSN received from its peer. 5424 * 5425 * The return value is the disposition. 5426 */ 5427 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5428 struct net *net, 5429 const struct sctp_endpoint *ep, 5430 const struct sctp_association *asoc, 5431 const union sctp_subtype type, 5432 void *arg, 5433 struct sctp_cmd_seq *commands) 5434 { 5435 struct sctp_chunk *reply; 5436 5437 /* Once all its outstanding data has been acknowledged, the 5438 * endpoint shall send a SHUTDOWN chunk to its peer including 5439 * in the Cumulative TSN Ack field the last sequential TSN it 5440 * has received from the peer. 5441 */ 5442 reply = sctp_make_shutdown(asoc, NULL); 5443 if (!reply) 5444 goto nomem; 5445 5446 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5447 * T2-shutdown timer. 5448 */ 5449 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5450 5451 /* It shall then start the T2-shutdown timer */ 5452 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5453 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5454 5455 /* RFC 4960 Section 9.2 5456 * The sender of the SHUTDOWN MAY also start an overall guard timer 5457 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5458 */ 5459 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5460 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5461 5462 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5463 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5464 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5465 5466 /* and enter the SHUTDOWN-SENT state. */ 5467 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5468 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5469 5470 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5471 * 5472 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5473 * or SHUTDOWN-ACK. 5474 */ 5475 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5476 5477 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5478 5479 return SCTP_DISPOSITION_CONSUME; 5480 5481 nomem: 5482 return SCTP_DISPOSITION_NOMEM; 5483 } 5484 5485 /* 5486 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5487 * 5488 * From Section 9.2: 5489 * 5490 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5491 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5492 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5493 * endpoint must re-send the SHUTDOWN ACK. 5494 * 5495 * The return value is the disposition. 5496 */ 5497 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5498 struct net *net, 5499 const struct sctp_endpoint *ep, 5500 const struct sctp_association *asoc, 5501 const union sctp_subtype type, 5502 void *arg, 5503 struct sctp_cmd_seq *commands) 5504 { 5505 struct sctp_chunk *chunk = arg; 5506 struct sctp_chunk *reply; 5507 5508 /* There are 2 ways of getting here: 5509 * 1) called in response to a SHUTDOWN chunk 5510 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5511 * 5512 * For the case (2), the arg parameter is set to NULL. We need 5513 * to check that we have a chunk before accessing it's fields. 5514 */ 5515 if (chunk) { 5516 if (!sctp_vtag_verify(chunk, asoc)) 5517 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5518 commands); 5519 5520 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5521 if (!sctp_chunk_length_valid( 5522 chunk, sizeof(struct sctp_shutdown_chunk))) 5523 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5524 arg, commands); 5525 } 5526 5527 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5528 * shall send a SHUTDOWN ACK ... 5529 */ 5530 reply = sctp_make_shutdown_ack(asoc, chunk); 5531 if (!reply) 5532 goto nomem; 5533 5534 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5535 * the T2-shutdown timer. 5536 */ 5537 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5538 5539 /* and start/restart a T2-shutdown timer of its own, */ 5540 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5541 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5542 5543 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5544 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5545 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5546 5547 /* Enter the SHUTDOWN-ACK-SENT state. */ 5548 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5549 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5550 5551 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5552 * 5553 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5554 * or SHUTDOWN-ACK. 5555 */ 5556 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5557 5558 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5559 5560 return SCTP_DISPOSITION_CONSUME; 5561 5562 nomem: 5563 return SCTP_DISPOSITION_NOMEM; 5564 } 5565 5566 /* 5567 * Ignore the event defined as other 5568 * 5569 * The return value is the disposition of the event. 5570 */ 5571 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5572 const struct sctp_endpoint *ep, 5573 const struct sctp_association *asoc, 5574 const union sctp_subtype type, 5575 void *arg, 5576 struct sctp_cmd_seq *commands) 5577 { 5578 pr_debug("%s: the event other type:%d is ignored\n", 5579 __func__, type.other); 5580 5581 return SCTP_DISPOSITION_DISCARD; 5582 } 5583 5584 /************************************************************ 5585 * These are the state functions for handling timeout events. 5586 ************************************************************/ 5587 5588 /* 5589 * RTX Timeout 5590 * 5591 * Section: 6.3.3 Handle T3-rtx Expiration 5592 * 5593 * Whenever the retransmission timer T3-rtx expires for a destination 5594 * address, do the following: 5595 * [See below] 5596 * 5597 * The return value is the disposition of the chunk. 5598 */ 5599 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5600 const struct sctp_endpoint *ep, 5601 const struct sctp_association *asoc, 5602 const union sctp_subtype type, 5603 void *arg, 5604 struct sctp_cmd_seq *commands) 5605 { 5606 struct sctp_transport *transport = arg; 5607 5608 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5609 5610 if (asoc->overall_error_count >= asoc->max_retrans) { 5611 if (asoc->peer.zero_window_announced && 5612 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5613 /* 5614 * We are here likely because the receiver had its rwnd 5615 * closed for a while and we have not been able to 5616 * transmit the locally queued data within the maximum 5617 * retransmission attempts limit. Start the T5 5618 * shutdown guard timer to give the receiver one last 5619 * chance and some additional time to recover before 5620 * aborting. 5621 */ 5622 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5623 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5624 } else { 5625 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5626 SCTP_ERROR(ETIMEDOUT)); 5627 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5628 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5629 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5630 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5631 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5632 return SCTP_DISPOSITION_DELETE_TCB; 5633 } 5634 } 5635 5636 /* E1) For the destination address for which the timer 5637 * expires, adjust its ssthresh with rules defined in Section 5638 * 7.2.3 and set the cwnd <- MTU. 5639 */ 5640 5641 /* E2) For the destination address for which the timer 5642 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5643 * maximum value discussed in rule C7 above (RTO.max) may be 5644 * used to provide an upper bound to this doubling operation. 5645 */ 5646 5647 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5648 * outstanding DATA chunks for the address for which the 5649 * T3-rtx has expired will fit into a single packet, subject 5650 * to the MTU constraint for the path corresponding to the 5651 * destination transport address to which the retransmission 5652 * is being sent (this may be different from the address for 5653 * which the timer expires [see Section 6.4]). Call this 5654 * value K. Bundle and retransmit those K DATA chunks in a 5655 * single packet to the destination endpoint. 5656 * 5657 * Note: Any DATA chunks that were sent to the address for 5658 * which the T3-rtx timer expired but did not fit in one MTU 5659 * (rule E3 above), should be marked for retransmission and 5660 * sent as soon as cwnd allows (normally when a SACK arrives). 5661 */ 5662 5663 /* Do some failure management (Section 8.2). */ 5664 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5665 5666 /* NB: Rules E4 and F1 are implicit in R1. */ 5667 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5668 5669 return SCTP_DISPOSITION_CONSUME; 5670 } 5671 5672 /* 5673 * Generate delayed SACK on timeout 5674 * 5675 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5676 * 5677 * The guidelines on delayed acknowledgement algorithm specified in 5678 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5679 * acknowledgement SHOULD be generated for at least every second packet 5680 * (not every second DATA chunk) received, and SHOULD be generated 5681 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5682 * some situations it may be beneficial for an SCTP transmitter to be 5683 * more conservative than the algorithms detailed in this document 5684 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5685 * the following algorithms allow. 5686 */ 5687 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5688 const struct sctp_endpoint *ep, 5689 const struct sctp_association *asoc, 5690 const union sctp_subtype type, 5691 void *arg, 5692 struct sctp_cmd_seq *commands) 5693 { 5694 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5695 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5696 return SCTP_DISPOSITION_CONSUME; 5697 } 5698 5699 /* 5700 * sctp_sf_t1_init_timer_expire 5701 * 5702 * Section: 4 Note: 2 5703 * Verification Tag: 5704 * Inputs 5705 * (endpoint, asoc) 5706 * 5707 * RFC 2960 Section 4 Notes 5708 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5709 * and re-start the T1-init timer without changing state. This MUST 5710 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5711 * endpoint MUST abort the initialization process and report the 5712 * error to SCTP user. 5713 * 5714 * Outputs 5715 * (timers, events) 5716 * 5717 */ 5718 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5719 struct net *net, 5720 const struct sctp_endpoint *ep, 5721 const struct sctp_association *asoc, 5722 const union sctp_subtype type, 5723 void *arg, 5724 struct sctp_cmd_seq *commands) 5725 { 5726 int attempts = asoc->init_err_counter + 1; 5727 struct sctp_chunk *repl = NULL; 5728 struct sctp_bind_addr *bp; 5729 5730 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5731 5732 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5733 5734 if (attempts <= asoc->max_init_attempts) { 5735 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5736 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5737 if (!repl) 5738 return SCTP_DISPOSITION_NOMEM; 5739 5740 /* Choose transport for INIT. */ 5741 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5742 SCTP_CHUNK(repl)); 5743 5744 /* Issue a sideeffect to do the needed accounting. */ 5745 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5746 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5747 5748 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5749 } else { 5750 pr_debug("%s: giving up on INIT, attempts:%d " 5751 "max_init_attempts:%d\n", __func__, attempts, 5752 asoc->max_init_attempts); 5753 5754 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5755 SCTP_ERROR(ETIMEDOUT)); 5756 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5757 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5758 return SCTP_DISPOSITION_DELETE_TCB; 5759 } 5760 5761 return SCTP_DISPOSITION_CONSUME; 5762 } 5763 5764 /* 5765 * sctp_sf_t1_cookie_timer_expire 5766 * 5767 * Section: 4 Note: 2 5768 * Verification Tag: 5769 * Inputs 5770 * (endpoint, asoc) 5771 * 5772 * RFC 2960 Section 4 Notes 5773 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5774 * COOKIE ECHO and re-start the T1-cookie timer without changing 5775 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5776 * After that, the endpoint MUST abort the initialization process and 5777 * report the error to SCTP user. 5778 * 5779 * Outputs 5780 * (timers, events) 5781 * 5782 */ 5783 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5784 struct net *net, 5785 const struct sctp_endpoint *ep, 5786 const struct sctp_association *asoc, 5787 const union sctp_subtype type, 5788 void *arg, 5789 struct sctp_cmd_seq *commands) 5790 { 5791 int attempts = asoc->init_err_counter + 1; 5792 struct sctp_chunk *repl = NULL; 5793 5794 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5795 5796 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5797 5798 if (attempts <= asoc->max_init_attempts) { 5799 repl = sctp_make_cookie_echo(asoc, NULL); 5800 if (!repl) 5801 return SCTP_DISPOSITION_NOMEM; 5802 5803 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5804 SCTP_CHUNK(repl)); 5805 /* Issue a sideeffect to do the needed accounting. */ 5806 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5807 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5808 5809 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5810 } else { 5811 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5812 SCTP_ERROR(ETIMEDOUT)); 5813 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5814 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5815 return SCTP_DISPOSITION_DELETE_TCB; 5816 } 5817 5818 return SCTP_DISPOSITION_CONSUME; 5819 } 5820 5821 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5822 * with the updated last sequential TSN received from its peer. 5823 * 5824 * An endpoint should limit the number of retransmissions of the 5825 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5826 * If this threshold is exceeded the endpoint should destroy the TCB and 5827 * MUST report the peer endpoint unreachable to the upper layer (and 5828 * thus the association enters the CLOSED state). The reception of any 5829 * packet from its peer (i.e. as the peer sends all of its queued DATA 5830 * chunks) should clear the endpoint's retransmission count and restart 5831 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5832 * all of its queued DATA chunks that have not yet been sent. 5833 */ 5834 enum sctp_disposition sctp_sf_t2_timer_expire( 5835 struct net *net, 5836 const struct sctp_endpoint *ep, 5837 const struct sctp_association *asoc, 5838 const union sctp_subtype type, 5839 void *arg, 5840 struct sctp_cmd_seq *commands) 5841 { 5842 struct sctp_chunk *reply = NULL; 5843 5844 pr_debug("%s: timer T2 expired\n", __func__); 5845 5846 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5847 5848 ((struct sctp_association *)asoc)->shutdown_retries++; 5849 5850 if (asoc->overall_error_count >= asoc->max_retrans) { 5851 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5852 SCTP_ERROR(ETIMEDOUT)); 5853 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5854 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5855 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5856 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5857 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5858 return SCTP_DISPOSITION_DELETE_TCB; 5859 } 5860 5861 switch (asoc->state) { 5862 case SCTP_STATE_SHUTDOWN_SENT: 5863 reply = sctp_make_shutdown(asoc, NULL); 5864 break; 5865 5866 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5867 reply = sctp_make_shutdown_ack(asoc, NULL); 5868 break; 5869 5870 default: 5871 BUG(); 5872 break; 5873 } 5874 5875 if (!reply) 5876 goto nomem; 5877 5878 /* Do some failure management (Section 8.2). 5879 * If we remove the transport an SHUTDOWN was last sent to, don't 5880 * do failure management. 5881 */ 5882 if (asoc->shutdown_last_sent_to) 5883 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5884 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5885 5886 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5887 * the T2-shutdown timer. 5888 */ 5889 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5890 5891 /* Restart the T2-shutdown timer. */ 5892 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5893 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5894 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5895 return SCTP_DISPOSITION_CONSUME; 5896 5897 nomem: 5898 return SCTP_DISPOSITION_NOMEM; 5899 } 5900 5901 /* 5902 * ADDIP Section 4.1 ASCONF CHunk Procedures 5903 * If the T4 RTO timer expires the endpoint should do B1 to B5 5904 */ 5905 enum sctp_disposition sctp_sf_t4_timer_expire( 5906 struct net *net, 5907 const struct sctp_endpoint *ep, 5908 const struct sctp_association *asoc, 5909 const union sctp_subtype type, 5910 void *arg, 5911 struct sctp_cmd_seq *commands) 5912 { 5913 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5914 struct sctp_transport *transport = chunk->transport; 5915 5916 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5917 5918 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5919 * detection on the appropriate destination address as defined in 5920 * RFC2960 [5] section 8.1 and 8.2. 5921 */ 5922 if (transport) 5923 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5924 SCTP_TRANSPORT(transport)); 5925 5926 /* Reconfig T4 timer and transport. */ 5927 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5928 5929 /* ADDIP 4.1 B2) Increment the association error counters and perform 5930 * endpoint failure detection on the association as defined in 5931 * RFC2960 [5] section 8.1 and 8.2. 5932 * association error counter is incremented in SCTP_CMD_STRIKE. 5933 */ 5934 if (asoc->overall_error_count >= asoc->max_retrans) { 5935 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5936 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5937 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5938 SCTP_ERROR(ETIMEDOUT)); 5939 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5940 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5941 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5942 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5943 return SCTP_DISPOSITION_ABORT; 5944 } 5945 5946 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5947 * the ASCONF chunk was sent by doubling the RTO timer value. 5948 * This is done in SCTP_CMD_STRIKE. 5949 */ 5950 5951 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5952 * choose an alternate destination address (please refer to RFC2960 5953 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5954 * chunk, it MUST be the same (including its serial number) as the last 5955 * ASCONF sent. 5956 */ 5957 sctp_chunk_hold(asoc->addip_last_asconf); 5958 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5959 SCTP_CHUNK(asoc->addip_last_asconf)); 5960 5961 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5962 * destination is selected, then the RTO used will be that of the new 5963 * destination address. 5964 */ 5965 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5966 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5967 5968 return SCTP_DISPOSITION_CONSUME; 5969 } 5970 5971 /* sctpimpguide-05 Section 2.12.2 5972 * The sender of the SHUTDOWN MAY also start an overall guard timer 5973 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5974 * At the expiration of this timer the sender SHOULD abort the association 5975 * by sending an ABORT chunk. 5976 */ 5977 enum sctp_disposition sctp_sf_t5_timer_expire( 5978 struct net *net, 5979 const struct sctp_endpoint *ep, 5980 const struct sctp_association *asoc, 5981 const union sctp_subtype type, 5982 void *arg, 5983 struct sctp_cmd_seq *commands) 5984 { 5985 struct sctp_chunk *reply = NULL; 5986 5987 pr_debug("%s: timer T5 expired\n", __func__); 5988 5989 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5990 5991 reply = sctp_make_abort(asoc, NULL, 0); 5992 if (!reply) 5993 goto nomem; 5994 5995 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5996 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5997 SCTP_ERROR(ETIMEDOUT)); 5998 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5999 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6000 6001 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6002 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6003 6004 return SCTP_DISPOSITION_DELETE_TCB; 6005 nomem: 6006 return SCTP_DISPOSITION_NOMEM; 6007 } 6008 6009 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6010 * the association is automatically closed by starting the shutdown process. 6011 * The work that needs to be done is same as when SHUTDOWN is initiated by 6012 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6013 */ 6014 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6015 struct net *net, 6016 const struct sctp_endpoint *ep, 6017 const struct sctp_association *asoc, 6018 const union sctp_subtype type, 6019 void *arg, 6020 struct sctp_cmd_seq *commands) 6021 { 6022 enum sctp_disposition disposition; 6023 6024 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6025 6026 /* From 9.2 Shutdown of an Association 6027 * Upon receipt of the SHUTDOWN primitive from its upper 6028 * layer, the endpoint enters SHUTDOWN-PENDING state and 6029 * remains there until all outstanding data has been 6030 * acknowledged by its peer. The endpoint accepts no new data 6031 * from its upper layer, but retransmits data to the far end 6032 * if necessary to fill gaps. 6033 */ 6034 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6035 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6036 6037 disposition = SCTP_DISPOSITION_CONSUME; 6038 if (sctp_outq_is_empty(&asoc->outqueue)) { 6039 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6040 arg, commands); 6041 } 6042 6043 return disposition; 6044 } 6045 6046 /***************************************************************************** 6047 * These are sa state functions which could apply to all types of events. 6048 ****************************************************************************/ 6049 6050 /* 6051 * This table entry is not implemented. 6052 * 6053 * Inputs 6054 * (endpoint, asoc, chunk) 6055 * 6056 * The return value is the disposition of the chunk. 6057 */ 6058 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6059 const struct sctp_endpoint *ep, 6060 const struct sctp_association *asoc, 6061 const union sctp_subtype type, 6062 void *arg, struct sctp_cmd_seq *commands) 6063 { 6064 return SCTP_DISPOSITION_NOT_IMPL; 6065 } 6066 6067 /* 6068 * This table entry represents a bug. 6069 * 6070 * Inputs 6071 * (endpoint, asoc, chunk) 6072 * 6073 * The return value is the disposition of the chunk. 6074 */ 6075 enum sctp_disposition sctp_sf_bug(struct net *net, 6076 const struct sctp_endpoint *ep, 6077 const struct sctp_association *asoc, 6078 const union sctp_subtype type, 6079 void *arg, struct sctp_cmd_seq *commands) 6080 { 6081 return SCTP_DISPOSITION_BUG; 6082 } 6083 6084 /* 6085 * This table entry represents the firing of a timer in the wrong state. 6086 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6087 * when the association is in the wrong state. This event should 6088 * be ignored, so as to prevent any rearming of the timer. 6089 * 6090 * Inputs 6091 * (endpoint, asoc, chunk) 6092 * 6093 * The return value is the disposition of the chunk. 6094 */ 6095 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6096 const struct sctp_endpoint *ep, 6097 const struct sctp_association *asoc, 6098 const union sctp_subtype type, 6099 void *arg, 6100 struct sctp_cmd_seq *commands) 6101 { 6102 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6103 6104 return SCTP_DISPOSITION_CONSUME; 6105 } 6106 6107 /******************************************************************** 6108 * 2nd Level Abstractions 6109 ********************************************************************/ 6110 6111 /* Pull the SACK chunk based on the SACK header. */ 6112 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6113 { 6114 struct sctp_sackhdr *sack; 6115 __u16 num_dup_tsns; 6116 unsigned int len; 6117 __u16 num_blocks; 6118 6119 /* Protect ourselves from reading too far into 6120 * the skb from a bogus sender. 6121 */ 6122 sack = (struct sctp_sackhdr *) chunk->skb->data; 6123 6124 num_blocks = ntohs(sack->num_gap_ack_blocks); 6125 num_dup_tsns = ntohs(sack->num_dup_tsns); 6126 len = sizeof(struct sctp_sackhdr); 6127 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6128 if (len > chunk->skb->len) 6129 return NULL; 6130 6131 skb_pull(chunk->skb, len); 6132 6133 return sack; 6134 } 6135 6136 /* Create an ABORT packet to be sent as a response, with the specified 6137 * error causes. 6138 */ 6139 static struct sctp_packet *sctp_abort_pkt_new( 6140 struct net *net, 6141 const struct sctp_endpoint *ep, 6142 const struct sctp_association *asoc, 6143 struct sctp_chunk *chunk, 6144 const void *payload, size_t paylen) 6145 { 6146 struct sctp_packet *packet; 6147 struct sctp_chunk *abort; 6148 6149 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6150 6151 if (packet) { 6152 /* Make an ABORT. 6153 * The T bit will be set if the asoc is NULL. 6154 */ 6155 abort = sctp_make_abort(asoc, chunk, paylen); 6156 if (!abort) { 6157 sctp_ootb_pkt_free(packet); 6158 return NULL; 6159 } 6160 6161 /* Reflect vtag if T-Bit is set */ 6162 if (sctp_test_T_bit(abort)) 6163 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6164 6165 /* Add specified error causes, i.e., payload, to the 6166 * end of the chunk. 6167 */ 6168 sctp_addto_chunk(abort, paylen, payload); 6169 6170 /* Set the skb to the belonging sock for accounting. */ 6171 abort->skb->sk = ep->base.sk; 6172 6173 sctp_packet_append_chunk(packet, abort); 6174 6175 } 6176 6177 return packet; 6178 } 6179 6180 /* Allocate a packet for responding in the OOTB conditions. */ 6181 static struct sctp_packet *sctp_ootb_pkt_new( 6182 struct net *net, 6183 const struct sctp_association *asoc, 6184 const struct sctp_chunk *chunk) 6185 { 6186 struct sctp_transport *transport; 6187 struct sctp_packet *packet; 6188 __u16 sport, dport; 6189 __u32 vtag; 6190 6191 /* Get the source and destination port from the inbound packet. */ 6192 sport = ntohs(chunk->sctp_hdr->dest); 6193 dport = ntohs(chunk->sctp_hdr->source); 6194 6195 /* The V-tag is going to be the same as the inbound packet if no 6196 * association exists, otherwise, use the peer's vtag. 6197 */ 6198 if (asoc) { 6199 /* Special case the INIT-ACK as there is no peer's vtag 6200 * yet. 6201 */ 6202 switch (chunk->chunk_hdr->type) { 6203 case SCTP_CID_INIT_ACK: 6204 { 6205 struct sctp_initack_chunk *initack; 6206 6207 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6208 vtag = ntohl(initack->init_hdr.init_tag); 6209 break; 6210 } 6211 default: 6212 vtag = asoc->peer.i.init_tag; 6213 break; 6214 } 6215 } else { 6216 /* Special case the INIT and stale COOKIE_ECHO as there is no 6217 * vtag yet. 6218 */ 6219 switch (chunk->chunk_hdr->type) { 6220 case SCTP_CID_INIT: 6221 { 6222 struct sctp_init_chunk *init; 6223 6224 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6225 vtag = ntohl(init->init_hdr.init_tag); 6226 break; 6227 } 6228 default: 6229 vtag = ntohl(chunk->sctp_hdr->vtag); 6230 break; 6231 } 6232 } 6233 6234 /* Make a transport for the bucket, Eliza... */ 6235 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6236 if (!transport) 6237 goto nomem; 6238 6239 /* Cache a route for the transport with the chunk's destination as 6240 * the source address. 6241 */ 6242 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6243 sctp_sk(net->sctp.ctl_sock)); 6244 6245 packet = &transport->packet; 6246 sctp_packet_init(packet, transport, sport, dport); 6247 sctp_packet_config(packet, vtag, 0); 6248 6249 return packet; 6250 6251 nomem: 6252 return NULL; 6253 } 6254 6255 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6256 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6257 { 6258 sctp_transport_free(packet->transport); 6259 } 6260 6261 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6262 static void sctp_send_stale_cookie_err(struct net *net, 6263 const struct sctp_endpoint *ep, 6264 const struct sctp_association *asoc, 6265 const struct sctp_chunk *chunk, 6266 struct sctp_cmd_seq *commands, 6267 struct sctp_chunk *err_chunk) 6268 { 6269 struct sctp_packet *packet; 6270 6271 if (err_chunk) { 6272 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6273 if (packet) { 6274 struct sctp_signed_cookie *cookie; 6275 6276 /* Override the OOTB vtag from the cookie. */ 6277 cookie = chunk->subh.cookie_hdr; 6278 packet->vtag = cookie->c.peer_vtag; 6279 6280 /* Set the skb to the belonging sock for accounting. */ 6281 err_chunk->skb->sk = ep->base.sk; 6282 sctp_packet_append_chunk(packet, err_chunk); 6283 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6284 SCTP_PACKET(packet)); 6285 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6286 } else 6287 sctp_chunk_free (err_chunk); 6288 } 6289 } 6290 6291 6292 /* Process a data chunk */ 6293 static int sctp_eat_data(const struct sctp_association *asoc, 6294 struct sctp_chunk *chunk, 6295 struct sctp_cmd_seq *commands) 6296 { 6297 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6298 struct sock *sk = asoc->base.sk; 6299 struct net *net = sock_net(sk); 6300 struct sctp_datahdr *data_hdr; 6301 struct sctp_chunk *err; 6302 enum sctp_verb deliver; 6303 size_t datalen; 6304 __u32 tsn; 6305 int tmp; 6306 6307 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6308 chunk->subh.data_hdr = data_hdr; 6309 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6310 6311 tsn = ntohl(data_hdr->tsn); 6312 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6313 6314 /* ASSERT: Now skb->data is really the user data. */ 6315 6316 /* Process ECN based congestion. 6317 * 6318 * Since the chunk structure is reused for all chunks within 6319 * a packet, we use ecn_ce_done to track if we've already 6320 * done CE processing for this packet. 6321 * 6322 * We need to do ECN processing even if we plan to discard the 6323 * chunk later. 6324 */ 6325 6326 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6327 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6328 chunk->ecn_ce_done = 1; 6329 6330 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6331 /* Do real work as sideffect. */ 6332 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6333 SCTP_U32(tsn)); 6334 } 6335 } 6336 6337 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6338 if (tmp < 0) { 6339 /* The TSN is too high--silently discard the chunk and 6340 * count on it getting retransmitted later. 6341 */ 6342 if (chunk->asoc) 6343 chunk->asoc->stats.outofseqtsns++; 6344 return SCTP_IERROR_HIGH_TSN; 6345 } else if (tmp > 0) { 6346 /* This is a duplicate. Record it. */ 6347 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6348 return SCTP_IERROR_DUP_TSN; 6349 } 6350 6351 /* This is a new TSN. */ 6352 6353 /* Discard if there is no room in the receive window. 6354 * Actually, allow a little bit of overflow (up to a MTU). 6355 */ 6356 datalen = ntohs(chunk->chunk_hdr->length); 6357 datalen -= sctp_datachk_len(&asoc->stream); 6358 6359 deliver = SCTP_CMD_CHUNK_ULP; 6360 6361 /* Think about partial delivery. */ 6362 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6363 6364 /* Even if we don't accept this chunk there is 6365 * memory pressure. 6366 */ 6367 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6368 } 6369 6370 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6371 * seems a bit troublesome in that frag_point varies based on 6372 * PMTU. In cases, such as loopback, this might be a rather 6373 * large spill over. 6374 */ 6375 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6376 (datalen > asoc->rwnd + asoc->frag_point))) { 6377 6378 /* If this is the next TSN, consider reneging to make 6379 * room. Note: Playing nice with a confused sender. A 6380 * malicious sender can still eat up all our buffer 6381 * space and in the future we may want to detect and 6382 * do more drastic reneging. 6383 */ 6384 if (sctp_tsnmap_has_gap(map) && 6385 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6386 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6387 deliver = SCTP_CMD_RENEGE; 6388 } else { 6389 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6390 __func__, tsn, datalen, asoc->rwnd); 6391 6392 return SCTP_IERROR_IGNORE_TSN; 6393 } 6394 } 6395 6396 /* 6397 * Also try to renege to limit our memory usage in the event that 6398 * we are under memory pressure 6399 * If we can't renege, don't worry about it, the sk_rmem_schedule 6400 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6401 * memory usage too much 6402 */ 6403 if (*sk->sk_prot_creator->memory_pressure) { 6404 if (sctp_tsnmap_has_gap(map) && 6405 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6406 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6407 __func__, tsn); 6408 deliver = SCTP_CMD_RENEGE; 6409 } 6410 } 6411 6412 /* 6413 * Section 3.3.10.9 No User Data (9) 6414 * 6415 * Cause of error 6416 * --------------- 6417 * No User Data: This error cause is returned to the originator of a 6418 * DATA chunk if a received DATA chunk has no user data. 6419 */ 6420 if (unlikely(0 == datalen)) { 6421 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6422 if (err) { 6423 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6424 SCTP_CHUNK(err)); 6425 } 6426 /* We are going to ABORT, so we might as well stop 6427 * processing the rest of the chunks in the packet. 6428 */ 6429 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6430 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6431 SCTP_ERROR(ECONNABORTED)); 6432 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6433 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6434 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6435 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6436 return SCTP_IERROR_NO_DATA; 6437 } 6438 6439 chunk->data_accepted = 1; 6440 6441 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6442 * if we renege and the chunk arrives again. 6443 */ 6444 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6445 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6446 if (chunk->asoc) 6447 chunk->asoc->stats.iuodchunks++; 6448 } else { 6449 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6450 if (chunk->asoc) 6451 chunk->asoc->stats.iodchunks++; 6452 } 6453 6454 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6455 * 6456 * If an endpoint receive a DATA chunk with an invalid stream 6457 * identifier, it shall acknowledge the reception of the DATA chunk 6458 * following the normal procedure, immediately send an ERROR chunk 6459 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6460 * and discard the DATA chunk. 6461 */ 6462 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6463 /* Mark tsn as received even though we drop it */ 6464 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6465 6466 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6467 &data_hdr->stream, 6468 sizeof(data_hdr->stream), 6469 sizeof(u16)); 6470 if (err) 6471 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6472 SCTP_CHUNK(err)); 6473 return SCTP_IERROR_BAD_STREAM; 6474 } 6475 6476 /* Check to see if the SSN is possible for this TSN. 6477 * The biggest gap we can record is 4K wide. Since SSNs wrap 6478 * at an unsigned short, there is no way that an SSN can 6479 * wrap and for a valid TSN. We can simply check if the current 6480 * SSN is smaller then the next expected one. If it is, it wrapped 6481 * and is invalid. 6482 */ 6483 if (!asoc->stream.si->validate_data(chunk)) 6484 return SCTP_IERROR_PROTO_VIOLATION; 6485 6486 /* Send the data up to the user. Note: Schedule the 6487 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6488 * chunk needs the updated rwnd. 6489 */ 6490 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6491 6492 return SCTP_IERROR_NO_ERROR; 6493 } 6494