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 const struct sctp_association *asoc, 157 struct sctp_chunk *chunk); 158 159 static enum sctp_disposition __sctp_sf_do_9_1_abort( 160 struct net *net, 161 const struct sctp_endpoint *ep, 162 const struct sctp_association *asoc, 163 const union sctp_subtype type, 164 void *arg, 165 struct sctp_cmd_seq *commands); 166 167 /* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: true = Valid length 171 * false = Invalid length 172 * 173 */ 174 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 175 __u16 required_length) 176 { 177 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 178 179 /* Previously already marked? */ 180 if (unlikely(chunk->pdiscard)) 181 return false; 182 if (unlikely(chunk_length < required_length)) 183 return false; 184 185 return true; 186 } 187 188 /********************************************************** 189 * These are the state functions for handling chunk events. 190 **********************************************************/ 191 192 /* 193 * Process the final SHUTDOWN COMPLETE. 194 * 195 * Section: 4 (C) (diagram), 9.2 196 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 197 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 198 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 199 * should stop the T2-shutdown timer and remove all knowledge of the 200 * association (and thus the association enters the CLOSED state). 201 * 202 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 203 * C) Rules for packet carrying SHUTDOWN COMPLETE: 204 * ... 205 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 206 * if the Verification Tag field of the packet matches its own tag and 207 * the T bit is not set 208 * OR 209 * it is set to its peer's tag and the T bit is set in the Chunk 210 * Flags. 211 * Otherwise, the receiver MUST silently discard the packet 212 * and take no further action. An endpoint MUST ignore the 213 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 214 * 215 * Inputs 216 * (endpoint, asoc, chunk) 217 * 218 * Outputs 219 * (asoc, reply_msg, msg_up, timers, counters) 220 * 221 * The return value is the disposition of the chunk. 222 */ 223 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 224 const struct sctp_endpoint *ep, 225 const struct sctp_association *asoc, 226 const union sctp_subtype type, 227 void *arg, struct sctp_cmd_seq *commands) 228 { 229 struct sctp_chunk *chunk = arg; 230 struct sctp_ulpevent *ev; 231 232 if (!sctp_vtag_verify_either(chunk, asoc)) 233 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 234 235 /* RFC 2960 6.10 Bundling 236 * 237 * An endpoint MUST NOT bundle INIT, INIT ACK or 238 * SHUTDOWN COMPLETE with any other chunks. 239 */ 240 if (!chunk->singleton) 241 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 242 243 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 244 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 245 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 246 commands); 247 248 /* RFC 2960 10.2 SCTP-to-ULP 249 * 250 * H) SHUTDOWN COMPLETE notification 251 * 252 * When SCTP completes the shutdown procedures (section 9.2) this 253 * notification is passed to the upper layer. 254 */ 255 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 256 0, 0, 0, NULL, GFP_ATOMIC); 257 if (ev) 258 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 259 SCTP_ULPEVENT(ev)); 260 261 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 262 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 263 * not the chunk should be discarded. If the endpoint is in 264 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 265 * T2-shutdown timer and remove all knowledge of the 266 * association (and thus the association enters the CLOSED 267 * state). 268 */ 269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 270 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 271 272 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 273 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 274 275 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 276 SCTP_STATE(SCTP_STATE_CLOSED)); 277 278 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 279 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 280 281 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 282 283 return SCTP_DISPOSITION_DELETE_TCB; 284 } 285 286 /* 287 * Respond to a normal INIT chunk. 288 * We are the side that is being asked for an association. 289 * 290 * Section: 5.1 Normal Establishment of an Association, B 291 * B) "Z" shall respond immediately with an INIT ACK chunk. The 292 * destination IP address of the INIT ACK MUST be set to the source 293 * IP address of the INIT to which this INIT ACK is responding. In 294 * the response, besides filling in other parameters, "Z" must set the 295 * Verification Tag field to Tag_A, and also provide its own 296 * Verification Tag (Tag_Z) in the Initiate Tag field. 297 * 298 * Verification Tag: Must be 0. 299 * 300 * Inputs 301 * (endpoint, asoc, chunk) 302 * 303 * Outputs 304 * (asoc, reply_msg, msg_up, timers, counters) 305 * 306 * The return value is the disposition of the chunk. 307 */ 308 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 309 const struct sctp_endpoint *ep, 310 const struct sctp_association *asoc, 311 const union sctp_subtype type, 312 void *arg, 313 struct sctp_cmd_seq *commands) 314 { 315 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 316 struct sctp_unrecognized_param *unk_param; 317 struct sctp_association *new_asoc; 318 struct sctp_packet *packet; 319 int len; 320 321 /* Update socket peer label if first association. */ 322 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 323 chunk->skb)) 324 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 325 326 /* 6.10 Bundling 327 * An endpoint MUST NOT bundle INIT, INIT ACK or 328 * SHUTDOWN COMPLETE with any other chunks. 329 * 330 * IG Section 2.11.2 331 * Furthermore, we require that the receiver of an INIT chunk MUST 332 * enforce these rules by silently discarding an arriving packet 333 * with an INIT chunk that is bundled with other chunks. 334 */ 335 if (!chunk->singleton) 336 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 337 338 /* If the packet is an OOTB packet which is temporarily on the 339 * control endpoint, respond with an ABORT. 340 */ 341 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 342 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 343 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 344 } 345 346 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 347 * Tag. 348 */ 349 if (chunk->sctp_hdr->vtag != 0) 350 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 351 352 /* Make sure that the INIT chunk has a valid length. 353 * Normally, this would cause an ABORT with a Protocol Violation 354 * error, but since we don't have an association, we'll 355 * just discard the packet. 356 */ 357 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 358 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 359 360 /* If the INIT is coming toward a closing socket, we'll send back 361 * and ABORT. Essentially, this catches the race of INIT being 362 * backloged to the socket at the same time as the user isses close(). 363 * Since the socket and all its associations are going away, we 364 * can treat this OOTB 365 */ 366 if (sctp_sstate(ep->base.sk, CLOSING)) 367 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 368 369 /* Verify the INIT chunk before processing it. */ 370 err_chunk = NULL; 371 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 372 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 373 &err_chunk)) { 374 /* This chunk contains fatal error. It is to be discarded. 375 * Send an ABORT, with causes if there is any. 376 */ 377 if (err_chunk) { 378 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 379 (__u8 *)(err_chunk->chunk_hdr) + 380 sizeof(struct sctp_chunkhdr), 381 ntohs(err_chunk->chunk_hdr->length) - 382 sizeof(struct sctp_chunkhdr)); 383 384 sctp_chunk_free(err_chunk); 385 386 if (packet) { 387 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 388 SCTP_PACKET(packet)); 389 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 390 return SCTP_DISPOSITION_CONSUME; 391 } else { 392 return SCTP_DISPOSITION_NOMEM; 393 } 394 } else { 395 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 396 commands); 397 } 398 } 399 400 /* Grab the INIT header. */ 401 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 402 403 /* Tag the variable length parameters. */ 404 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 405 406 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 407 if (!new_asoc) 408 goto nomem; 409 410 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 411 sctp_scope(sctp_source(chunk)), 412 GFP_ATOMIC) < 0) 413 goto nomem_init; 414 415 /* The call, sctp_process_init(), can fail on memory allocation. */ 416 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 417 (struct sctp_init_chunk *)chunk->chunk_hdr, 418 GFP_ATOMIC)) 419 goto nomem_init; 420 421 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 422 423 /* If there are errors need to be reported for unknown parameters, 424 * make sure to reserve enough room in the INIT ACK for them. 425 */ 426 len = 0; 427 if (err_chunk) 428 len = ntohs(err_chunk->chunk_hdr->length) - 429 sizeof(struct sctp_chunkhdr); 430 431 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 432 if (!repl) 433 goto nomem_init; 434 435 /* If there are errors need to be reported for unknown parameters, 436 * include them in the outgoing INIT ACK as "Unrecognized parameter" 437 * parameter. 438 */ 439 if (err_chunk) { 440 /* Get the "Unrecognized parameter" parameter(s) out of the 441 * ERROR chunk generated by sctp_verify_init(). Since the 442 * error cause code for "unknown parameter" and the 443 * "Unrecognized parameter" type is the same, we can 444 * construct the parameters in INIT ACK by copying the 445 * ERROR causes over. 446 */ 447 unk_param = (struct sctp_unrecognized_param *) 448 ((__u8 *)(err_chunk->chunk_hdr) + 449 sizeof(struct sctp_chunkhdr)); 450 /* Replace the cause code with the "Unrecognized parameter" 451 * parameter type. 452 */ 453 sctp_addto_chunk(repl, len, unk_param); 454 sctp_chunk_free(err_chunk); 455 } 456 457 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 458 459 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 460 461 /* 462 * Note: After sending out INIT ACK with the State Cookie parameter, 463 * "Z" MUST NOT allocate any resources, nor keep any states for the 464 * new association. Otherwise, "Z" will be vulnerable to resource 465 * attacks. 466 */ 467 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 468 469 return SCTP_DISPOSITION_DELETE_TCB; 470 471 nomem_init: 472 sctp_association_free(new_asoc); 473 nomem: 474 if (err_chunk) 475 sctp_chunk_free(err_chunk); 476 return SCTP_DISPOSITION_NOMEM; 477 } 478 479 /* 480 * Respond to a normal INIT ACK chunk. 481 * We are the side that is initiating the association. 482 * 483 * Section: 5.1 Normal Establishment of an Association, C 484 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 485 * timer and leave COOKIE-WAIT state. "A" shall then send the State 486 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 487 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 488 * 489 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 490 * DATA chunks, but it MUST be the first chunk in the packet and 491 * until the COOKIE ACK is returned the sender MUST NOT send any 492 * other packets to the peer. 493 * 494 * Verification Tag: 3.3.3 495 * If the value of the Initiate Tag in a received INIT ACK chunk is 496 * found to be 0, the receiver MUST treat it as an error and close the 497 * association by transmitting an ABORT. 498 * 499 * Inputs 500 * (endpoint, asoc, chunk) 501 * 502 * Outputs 503 * (asoc, reply_msg, msg_up, timers, counters) 504 * 505 * The return value is the disposition of the chunk. 506 */ 507 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 508 const struct sctp_endpoint *ep, 509 const struct sctp_association *asoc, 510 const union sctp_subtype type, 511 void *arg, 512 struct sctp_cmd_seq *commands) 513 { 514 struct sctp_init_chunk *initchunk; 515 struct sctp_chunk *chunk = arg; 516 struct sctp_chunk *err_chunk; 517 struct sctp_packet *packet; 518 519 if (!sctp_vtag_verify(chunk, asoc)) 520 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 521 522 /* 6.10 Bundling 523 * An endpoint MUST NOT bundle INIT, INIT ACK or 524 * SHUTDOWN COMPLETE with any other chunks. 525 */ 526 if (!chunk->singleton) 527 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 528 529 /* Make sure that the INIT-ACK chunk has a valid length */ 530 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 531 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 532 commands); 533 /* Grab the INIT header. */ 534 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 535 536 /* Verify the INIT chunk before processing it. */ 537 err_chunk = NULL; 538 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 539 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 540 &err_chunk)) { 541 542 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 543 544 /* This chunk contains fatal error. It is to be discarded. 545 * Send an ABORT, with causes. If there are no causes, 546 * then there wasn't enough memory. Just terminate 547 * the association. 548 */ 549 if (err_chunk) { 550 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 551 (__u8 *)(err_chunk->chunk_hdr) + 552 sizeof(struct sctp_chunkhdr), 553 ntohs(err_chunk->chunk_hdr->length) - 554 sizeof(struct sctp_chunkhdr)); 555 556 sctp_chunk_free(err_chunk); 557 558 if (packet) { 559 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 560 SCTP_PACKET(packet)); 561 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 562 error = SCTP_ERROR_INV_PARAM; 563 } 564 } 565 566 /* SCTP-AUTH, Section 6.3: 567 * It should be noted that if the receiver wants to tear 568 * down an association in an authenticated way only, the 569 * handling of malformed packets should not result in 570 * tearing down the association. 571 * 572 * This means that if we only want to abort associations 573 * in an authenticated way (i.e AUTH+ABORT), then we 574 * can't destroy this association just because the packet 575 * was malformed. 576 */ 577 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 578 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 579 580 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 581 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 582 asoc, chunk->transport); 583 } 584 585 /* Tag the variable length parameters. Note that we never 586 * convert the parameters in an INIT chunk. 587 */ 588 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 589 590 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 591 592 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 593 SCTP_PEER_INIT(initchunk)); 594 595 /* Reset init error count upon receipt of INIT-ACK. */ 596 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 597 598 /* 5.1 C) "A" shall stop the T1-init timer and leave 599 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 600 * timer, and enter the COOKIE-ECHOED state. 601 */ 602 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 603 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 604 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 605 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 606 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 607 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 608 609 /* SCTP-AUTH: genereate the assocition shared keys so that 610 * we can potentially signe the COOKIE-ECHO. 611 */ 612 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 613 614 /* 5.1 C) "A" shall then send the State Cookie received in the 615 * INIT ACK chunk in a COOKIE ECHO chunk, ... 616 */ 617 /* If there is any errors to report, send the ERROR chunk generated 618 * for unknown parameters as well. 619 */ 620 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 621 SCTP_CHUNK(err_chunk)); 622 623 return SCTP_DISPOSITION_CONSUME; 624 } 625 626 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, 627 const struct sctp_association *asoc) 628 { 629 struct sctp_chunk auth; 630 631 if (!chunk->auth_chunk) 632 return true; 633 634 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 635 * is supposed to be authenticated and we have to do delayed 636 * authentication. We've just recreated the association using 637 * the information in the cookie and now it's much easier to 638 * do the authentication. 639 */ 640 641 /* Make sure that we and the peer are AUTH capable */ 642 if (!net->sctp.auth_enable || !asoc->peer.auth_capable) 643 return false; 644 645 /* set-up our fake chunk so that we can process it */ 646 auth.skb = chunk->auth_chunk; 647 auth.asoc = chunk->asoc; 648 auth.sctp_hdr = chunk->sctp_hdr; 649 auth.chunk_hdr = (struct sctp_chunkhdr *) 650 skb_push(chunk->auth_chunk, 651 sizeof(struct sctp_chunkhdr)); 652 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 653 auth.transport = chunk->transport; 654 655 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR; 656 } 657 658 /* 659 * Respond to a normal COOKIE ECHO chunk. 660 * We are the side that is being asked for an association. 661 * 662 * Section: 5.1 Normal Establishment of an Association, D 663 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 664 * with a COOKIE ACK chunk after building a TCB and moving to 665 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 666 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 667 * chunk MUST be the first chunk in the packet. 668 * 669 * IMPLEMENTATION NOTE: An implementation may choose to send the 670 * Communication Up notification to the SCTP user upon reception 671 * of a valid COOKIE ECHO chunk. 672 * 673 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 674 * D) Rules for packet carrying a COOKIE ECHO 675 * 676 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 677 * Initial Tag received in the INIT ACK. 678 * 679 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 680 * 681 * Inputs 682 * (endpoint, asoc, chunk) 683 * 684 * Outputs 685 * (asoc, reply_msg, msg_up, timers, counters) 686 * 687 * The return value is the disposition of the chunk. 688 */ 689 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 690 const struct sctp_endpoint *ep, 691 const struct sctp_association *asoc, 692 const union sctp_subtype type, 693 void *arg, 694 struct sctp_cmd_seq *commands) 695 { 696 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 697 struct sctp_association *new_asoc; 698 struct sctp_init_chunk *peer_init; 699 struct sctp_chunk *chunk = arg; 700 struct sctp_chunk *err_chk_p; 701 struct sctp_chunk *repl; 702 struct sock *sk; 703 int error = 0; 704 705 /* If the packet is an OOTB packet which is temporarily on the 706 * control endpoint, respond with an ABORT. 707 */ 708 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 709 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 710 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 711 } 712 713 /* Make sure that the COOKIE_ECHO chunk has a valid length. 714 * In this case, we check that we have enough for at least a 715 * chunk header. More detailed verification is done 716 * in sctp_unpack_cookie(). 717 */ 718 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 719 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 720 721 /* If the endpoint is not listening or if the number of associations 722 * on the TCP-style socket exceed the max backlog, respond with an 723 * ABORT. 724 */ 725 sk = ep->base.sk; 726 if (!sctp_sstate(sk, LISTENING) || 727 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 728 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 729 730 /* "Decode" the chunk. We have no optional parameters so we 731 * are in good shape. 732 */ 733 chunk->subh.cookie_hdr = 734 (struct sctp_signed_cookie *)chunk->skb->data; 735 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 736 sizeof(struct sctp_chunkhdr))) 737 goto nomem; 738 739 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 740 * "Z" will reply with a COOKIE ACK chunk after building a TCB 741 * and moving to the ESTABLISHED state. 742 */ 743 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 744 &err_chk_p); 745 746 /* FIXME: 747 * If the re-build failed, what is the proper error path 748 * from here? 749 * 750 * [We should abort the association. --piggy] 751 */ 752 if (!new_asoc) { 753 /* FIXME: Several errors are possible. A bad cookie should 754 * be silently discarded, but think about logging it too. 755 */ 756 switch (error) { 757 case -SCTP_IERROR_NOMEM: 758 goto nomem; 759 760 case -SCTP_IERROR_STALE_COOKIE: 761 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 762 err_chk_p); 763 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 764 765 case -SCTP_IERROR_BAD_SIG: 766 default: 767 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 768 } 769 } 770 771 772 /* Delay state machine commands until later. 773 * 774 * Re-build the bind address for the association is done in 775 * the sctp_unpack_cookie() already. 776 */ 777 /* This is a brand-new association, so these are not yet side 778 * effects--it is safe to run them here. 779 */ 780 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 781 782 if (!sctp_process_init(new_asoc, chunk, 783 &chunk->subh.cookie_hdr->c.peer_addr, 784 peer_init, GFP_ATOMIC)) 785 goto nomem_init; 786 787 /* SCTP-AUTH: Now that we've populate required fields in 788 * sctp_process_init, set up the assocaition shared keys as 789 * necessary so that we can potentially authenticate the ACK 790 */ 791 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 792 if (error) 793 goto nomem_init; 794 795 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) { 796 sctp_association_free(new_asoc); 797 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 798 } 799 800 repl = sctp_make_cookie_ack(new_asoc, chunk); 801 if (!repl) 802 goto nomem_init; 803 804 /* RFC 2960 5.1 Normal Establishment of an Association 805 * 806 * D) IMPLEMENTATION NOTE: An implementation may choose to 807 * send the Communication Up notification to the SCTP user 808 * upon reception of a valid COOKIE ECHO chunk. 809 */ 810 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 811 new_asoc->c.sinit_num_ostreams, 812 new_asoc->c.sinit_max_instreams, 813 NULL, GFP_ATOMIC); 814 if (!ev) 815 goto nomem_ev; 816 817 /* Sockets API Draft Section 5.3.1.6 818 * When a peer sends a Adaptation Layer Indication parameter , SCTP 819 * delivers this notification to inform the application that of the 820 * peers requested adaptation layer. 821 */ 822 if (new_asoc->peer.adaptation_ind) { 823 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 824 GFP_ATOMIC); 825 if (!ai_ev) 826 goto nomem_aiev; 827 } 828 829 if (!new_asoc->peer.auth_capable) { 830 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 831 SCTP_AUTH_NO_AUTH, 832 GFP_ATOMIC); 833 if (!auth_ev) 834 goto nomem_authev; 835 } 836 837 /* Add all the state machine commands now since we've created 838 * everything. This way we don't introduce memory corruptions 839 * during side-effect processing and correclty count established 840 * associations. 841 */ 842 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 843 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 844 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 845 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 846 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 847 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 848 849 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 850 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 851 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 852 853 /* This will send the COOKIE ACK */ 854 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 855 856 /* Queue the ASSOC_CHANGE event */ 857 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 858 859 /* Send up the Adaptation Layer Indication event */ 860 if (ai_ev) 861 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 862 SCTP_ULPEVENT(ai_ev)); 863 864 if (auth_ev) 865 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 866 SCTP_ULPEVENT(auth_ev)); 867 868 return SCTP_DISPOSITION_CONSUME; 869 870 nomem_authev: 871 sctp_ulpevent_free(ai_ev); 872 nomem_aiev: 873 sctp_ulpevent_free(ev); 874 nomem_ev: 875 sctp_chunk_free(repl); 876 nomem_init: 877 sctp_association_free(new_asoc); 878 nomem: 879 return SCTP_DISPOSITION_NOMEM; 880 } 881 882 /* 883 * Respond to a normal COOKIE ACK chunk. 884 * We are the side that is asking for an association. 885 * 886 * RFC 2960 5.1 Normal Establishment of an Association 887 * 888 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 889 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 890 * timer. It may also notify its ULP about the successful 891 * establishment of the association with a Communication Up 892 * notification (see Section 10). 893 * 894 * Verification Tag: 895 * Inputs 896 * (endpoint, asoc, chunk) 897 * 898 * Outputs 899 * (asoc, reply_msg, msg_up, timers, counters) 900 * 901 * The return value is the disposition of the chunk. 902 */ 903 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 904 const struct sctp_endpoint *ep, 905 const struct sctp_association *asoc, 906 const union sctp_subtype type, 907 void *arg, 908 struct sctp_cmd_seq *commands) 909 { 910 struct sctp_chunk *chunk = arg; 911 struct sctp_ulpevent *ev; 912 913 if (!sctp_vtag_verify(chunk, asoc)) 914 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 915 916 /* Verify that the chunk length for the COOKIE-ACK is OK. 917 * If we don't do this, any bundled chunks may be junked. 918 */ 919 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 920 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 921 commands); 922 923 /* Reset init error count upon receipt of COOKIE-ACK, 924 * to avoid problems with the managemement of this 925 * counter in stale cookie situations when a transition back 926 * from the COOKIE-ECHOED state to the COOKIE-WAIT 927 * state is performed. 928 */ 929 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 930 931 /* Set peer label for connection. */ 932 security_inet_conn_established(ep->base.sk, chunk->skb); 933 934 /* RFC 2960 5.1 Normal Establishment of an Association 935 * 936 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 937 * from the COOKIE-ECHOED state to the ESTABLISHED state, 938 * stopping the T1-cookie timer. 939 */ 940 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 941 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 942 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 943 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 944 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 945 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 946 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 947 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 948 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 949 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 950 951 /* It may also notify its ULP about the successful 952 * establishment of the association with a Communication Up 953 * notification (see Section 10). 954 */ 955 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 956 0, asoc->c.sinit_num_ostreams, 957 asoc->c.sinit_max_instreams, 958 NULL, GFP_ATOMIC); 959 960 if (!ev) 961 goto nomem; 962 963 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 964 965 /* Sockets API Draft Section 5.3.1.6 966 * When a peer sends a Adaptation Layer Indication parameter , SCTP 967 * delivers this notification to inform the application that of the 968 * peers requested adaptation layer. 969 */ 970 if (asoc->peer.adaptation_ind) { 971 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 972 if (!ev) 973 goto nomem; 974 975 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 976 SCTP_ULPEVENT(ev)); 977 } 978 979 if (!asoc->peer.auth_capable) { 980 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 981 GFP_ATOMIC); 982 if (!ev) 983 goto nomem; 984 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 985 SCTP_ULPEVENT(ev)); 986 } 987 988 return SCTP_DISPOSITION_CONSUME; 989 nomem: 990 return SCTP_DISPOSITION_NOMEM; 991 } 992 993 /* Generate and sendout a heartbeat packet. */ 994 static enum sctp_disposition sctp_sf_heartbeat( 995 const struct sctp_endpoint *ep, 996 const struct sctp_association *asoc, 997 const union sctp_subtype type, 998 void *arg, 999 struct sctp_cmd_seq *commands) 1000 { 1001 struct sctp_transport *transport = (struct sctp_transport *) arg; 1002 struct sctp_chunk *reply; 1003 1004 /* Send a heartbeat to our peer. */ 1005 reply = sctp_make_heartbeat(asoc, transport); 1006 if (!reply) 1007 return SCTP_DISPOSITION_NOMEM; 1008 1009 /* Set rto_pending indicating that an RTT measurement 1010 * is started with this heartbeat chunk. 1011 */ 1012 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1013 SCTP_TRANSPORT(transport)); 1014 1015 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1016 return SCTP_DISPOSITION_CONSUME; 1017 } 1018 1019 /* Generate a HEARTBEAT packet on the given transport. */ 1020 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1021 const struct sctp_endpoint *ep, 1022 const struct sctp_association *asoc, 1023 const union sctp_subtype type, 1024 void *arg, 1025 struct sctp_cmd_seq *commands) 1026 { 1027 struct sctp_transport *transport = (struct sctp_transport *) arg; 1028 1029 if (asoc->overall_error_count >= asoc->max_retrans) { 1030 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1031 SCTP_ERROR(ETIMEDOUT)); 1032 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1033 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1034 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1035 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1036 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1037 return SCTP_DISPOSITION_DELETE_TCB; 1038 } 1039 1040 /* Section 3.3.5. 1041 * The Sender-specific Heartbeat Info field should normally include 1042 * information about the sender's current time when this HEARTBEAT 1043 * chunk is sent and the destination transport address to which this 1044 * HEARTBEAT is sent (see Section 8.3). 1045 */ 1046 1047 if (transport->param_flags & SPP_HB_ENABLE) { 1048 if (SCTP_DISPOSITION_NOMEM == 1049 sctp_sf_heartbeat(ep, asoc, type, arg, 1050 commands)) 1051 return SCTP_DISPOSITION_NOMEM; 1052 1053 /* Set transport error counter and association error counter 1054 * when sending heartbeat. 1055 */ 1056 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1057 SCTP_TRANSPORT(transport)); 1058 } 1059 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1060 SCTP_TRANSPORT(transport)); 1061 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1062 SCTP_TRANSPORT(transport)); 1063 1064 return SCTP_DISPOSITION_CONSUME; 1065 } 1066 1067 /* resend asoc strreset_chunk. */ 1068 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1069 const struct sctp_endpoint *ep, 1070 const struct sctp_association *asoc, 1071 const union sctp_subtype type, 1072 void *arg, 1073 struct sctp_cmd_seq *commands) 1074 { 1075 struct sctp_transport *transport = arg; 1076 1077 if (asoc->overall_error_count >= asoc->max_retrans) { 1078 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1079 SCTP_ERROR(ETIMEDOUT)); 1080 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1081 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1082 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1083 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1084 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1085 return SCTP_DISPOSITION_DELETE_TCB; 1086 } 1087 1088 sctp_chunk_hold(asoc->strreset_chunk); 1089 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1090 SCTP_CHUNK(asoc->strreset_chunk)); 1091 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1092 1093 return SCTP_DISPOSITION_CONSUME; 1094 } 1095 1096 /* 1097 * Process an heartbeat request. 1098 * 1099 * Section: 8.3 Path Heartbeat 1100 * The receiver of the HEARTBEAT should immediately respond with a 1101 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1102 * from the received HEARTBEAT chunk. 1103 * 1104 * Verification Tag: 8.5 Verification Tag [Normal verification] 1105 * When receiving an SCTP packet, the endpoint MUST ensure that the 1106 * value in the Verification Tag field of the received SCTP packet 1107 * matches its own Tag. If the received Verification Tag value does not 1108 * match the receiver's own tag value, the receiver shall silently 1109 * discard the packet and shall not process it any further except for 1110 * those cases listed in Section 8.5.1 below. 1111 * 1112 * Inputs 1113 * (endpoint, asoc, chunk) 1114 * 1115 * Outputs 1116 * (asoc, reply_msg, msg_up, timers, counters) 1117 * 1118 * The return value is the disposition of the chunk. 1119 */ 1120 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1121 const struct sctp_endpoint *ep, 1122 const struct sctp_association *asoc, 1123 const union sctp_subtype type, 1124 void *arg, struct sctp_cmd_seq *commands) 1125 { 1126 struct sctp_paramhdr *param_hdr; 1127 struct sctp_chunk *chunk = arg; 1128 struct sctp_chunk *reply; 1129 size_t paylen = 0; 1130 1131 if (!sctp_vtag_verify(chunk, asoc)) 1132 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1133 1134 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1135 if (!sctp_chunk_length_valid(chunk, 1136 sizeof(struct sctp_heartbeat_chunk))) 1137 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1138 commands); 1139 1140 /* 8.3 The receiver of the HEARTBEAT should immediately 1141 * respond with a HEARTBEAT ACK that contains the Heartbeat 1142 * Information field copied from the received HEARTBEAT chunk. 1143 */ 1144 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1145 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1146 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1147 1148 if (ntohs(param_hdr->length) > paylen) 1149 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1150 param_hdr, commands); 1151 1152 if (!pskb_pull(chunk->skb, paylen)) 1153 goto nomem; 1154 1155 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1156 if (!reply) 1157 goto nomem; 1158 1159 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1160 return SCTP_DISPOSITION_CONSUME; 1161 1162 nomem: 1163 return SCTP_DISPOSITION_NOMEM; 1164 } 1165 1166 /* 1167 * Process the returning HEARTBEAT ACK. 1168 * 1169 * Section: 8.3 Path Heartbeat 1170 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1171 * should clear the error counter of the destination transport 1172 * address to which the HEARTBEAT was sent, and mark the destination 1173 * transport address as active if it is not so marked. The endpoint may 1174 * optionally report to the upper layer when an inactive destination 1175 * address is marked as active due to the reception of the latest 1176 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1177 * clear the association overall error count as well (as defined 1178 * in section 8.1). 1179 * 1180 * The receiver of the HEARTBEAT ACK should also perform an RTT 1181 * measurement for that destination transport address using the time 1182 * value carried in the HEARTBEAT ACK chunk. 1183 * 1184 * Verification Tag: 8.5 Verification Tag [Normal verification] 1185 * 1186 * Inputs 1187 * (endpoint, asoc, chunk) 1188 * 1189 * Outputs 1190 * (asoc, reply_msg, msg_up, timers, counters) 1191 * 1192 * The return value is the disposition of the chunk. 1193 */ 1194 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1195 const struct sctp_endpoint *ep, 1196 const struct sctp_association *asoc, 1197 const union sctp_subtype type, 1198 void *arg, 1199 struct sctp_cmd_seq *commands) 1200 { 1201 struct sctp_sender_hb_info *hbinfo; 1202 struct sctp_chunk *chunk = arg; 1203 struct sctp_transport *link; 1204 unsigned long max_interval; 1205 union sctp_addr from_addr; 1206 1207 if (!sctp_vtag_verify(chunk, asoc)) 1208 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1209 1210 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1211 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1212 sizeof(*hbinfo))) 1213 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1214 commands); 1215 1216 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1217 /* Make sure that the length of the parameter is what we expect */ 1218 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1219 return SCTP_DISPOSITION_DISCARD; 1220 1221 from_addr = hbinfo->daddr; 1222 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1223 1224 /* This should never happen, but lets log it if so. */ 1225 if (unlikely(!link)) { 1226 if (from_addr.sa.sa_family == AF_INET6) { 1227 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1228 __func__, 1229 asoc, 1230 &from_addr.v6.sin6_addr); 1231 } else { 1232 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1233 __func__, 1234 asoc, 1235 &from_addr.v4.sin_addr.s_addr); 1236 } 1237 return SCTP_DISPOSITION_DISCARD; 1238 } 1239 1240 /* Validate the 64-bit random nonce. */ 1241 if (hbinfo->hb_nonce != link->hb_nonce) 1242 return SCTP_DISPOSITION_DISCARD; 1243 1244 max_interval = link->hbinterval + link->rto; 1245 1246 /* Check if the timestamp looks valid. */ 1247 if (time_after(hbinfo->sent_at, jiffies) || 1248 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1249 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1250 "for transport:%p\n", __func__, link); 1251 1252 return SCTP_DISPOSITION_DISCARD; 1253 } 1254 1255 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1256 * the HEARTBEAT should clear the error counter of the 1257 * destination transport address to which the HEARTBEAT was 1258 * sent and mark the destination transport address as active if 1259 * it is not so marked. 1260 */ 1261 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1262 1263 return SCTP_DISPOSITION_CONSUME; 1264 } 1265 1266 /* Helper function to send out an abort for the restart 1267 * condition. 1268 */ 1269 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1270 struct sctp_chunk *init, 1271 struct sctp_cmd_seq *commands) 1272 { 1273 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1274 union sctp_addr_param *addrparm; 1275 struct sctp_errhdr *errhdr; 1276 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1277 struct sctp_endpoint *ep; 1278 struct sctp_packet *pkt; 1279 int len; 1280 1281 /* Build the error on the stack. We are way to malloc crazy 1282 * throughout the code today. 1283 */ 1284 errhdr = (struct sctp_errhdr *)buffer; 1285 addrparm = (union sctp_addr_param *)errhdr->variable; 1286 1287 /* Copy into a parm format. */ 1288 len = af->to_addr_param(ssa, addrparm); 1289 len += sizeof(*errhdr); 1290 1291 errhdr->cause = SCTP_ERROR_RESTART; 1292 errhdr->length = htons(len); 1293 1294 /* Assign to the control socket. */ 1295 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1296 1297 /* Association is NULL since this may be a restart attack and we 1298 * want to send back the attacker's vtag. 1299 */ 1300 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1301 1302 if (!pkt) 1303 goto out; 1304 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1305 1306 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1307 1308 /* Discard the rest of the inbound packet. */ 1309 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1310 1311 out: 1312 /* Even if there is no memory, treat as a failure so 1313 * the packet will get dropped. 1314 */ 1315 return 0; 1316 } 1317 1318 static bool list_has_sctp_addr(const struct list_head *list, 1319 union sctp_addr *ipaddr) 1320 { 1321 struct sctp_transport *addr; 1322 1323 list_for_each_entry(addr, list, transports) { 1324 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1325 return true; 1326 } 1327 1328 return false; 1329 } 1330 /* A restart is occurring, check to make sure no new addresses 1331 * are being added as we may be under a takeover attack. 1332 */ 1333 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1334 const struct sctp_association *asoc, 1335 struct sctp_chunk *init, 1336 struct sctp_cmd_seq *commands) 1337 { 1338 struct net *net = sock_net(new_asoc->base.sk); 1339 struct sctp_transport *new_addr; 1340 int ret = 1; 1341 1342 /* Implementor's Guide - Section 5.2.2 1343 * ... 1344 * Before responding the endpoint MUST check to see if the 1345 * unexpected INIT adds new addresses to the association. If new 1346 * addresses are added to the association, the endpoint MUST respond 1347 * with an ABORT.. 1348 */ 1349 1350 /* Search through all current addresses and make sure 1351 * we aren't adding any new ones. 1352 */ 1353 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1354 transports) { 1355 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1356 &new_addr->ipaddr)) { 1357 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1358 commands); 1359 ret = 0; 1360 break; 1361 } 1362 } 1363 1364 /* Return success if all addresses were found. */ 1365 return ret; 1366 } 1367 1368 /* Populate the verification/tie tags based on overlapping INIT 1369 * scenario. 1370 * 1371 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1372 */ 1373 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1374 const struct sctp_association *asoc) 1375 { 1376 switch (asoc->state) { 1377 1378 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1379 1380 case SCTP_STATE_COOKIE_WAIT: 1381 new_asoc->c.my_vtag = asoc->c.my_vtag; 1382 new_asoc->c.my_ttag = asoc->c.my_vtag; 1383 new_asoc->c.peer_ttag = 0; 1384 break; 1385 1386 case SCTP_STATE_COOKIE_ECHOED: 1387 new_asoc->c.my_vtag = asoc->c.my_vtag; 1388 new_asoc->c.my_ttag = asoc->c.my_vtag; 1389 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1390 break; 1391 1392 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1393 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1394 */ 1395 default: 1396 new_asoc->c.my_ttag = asoc->c.my_vtag; 1397 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1398 break; 1399 } 1400 1401 /* Other parameters for the endpoint SHOULD be copied from the 1402 * existing parameters of the association (e.g. number of 1403 * outbound streams) into the INIT ACK and cookie. 1404 */ 1405 new_asoc->rwnd = asoc->rwnd; 1406 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1407 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1408 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1409 } 1410 1411 /* 1412 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1413 * handling action. 1414 * 1415 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1416 * 1417 * Returns value representing action to be taken. These action values 1418 * correspond to Action/Description values in RFC 2960, Table 2. 1419 */ 1420 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1421 const struct sctp_association *asoc) 1422 { 1423 /* In this case, the peer may have restarted. */ 1424 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1425 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1426 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1427 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1428 return 'A'; 1429 1430 /* Collision case B. */ 1431 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1432 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1433 (0 == asoc->c.peer_vtag))) { 1434 return 'B'; 1435 } 1436 1437 /* Collision case D. */ 1438 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1439 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1440 return 'D'; 1441 1442 /* Collision case C. */ 1443 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1444 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1445 (0 == new_asoc->c.my_ttag) && 1446 (0 == new_asoc->c.peer_ttag)) 1447 return 'C'; 1448 1449 /* No match to any of the special cases; discard this packet. */ 1450 return 'E'; 1451 } 1452 1453 /* Common helper routine for both duplicate and simulataneous INIT 1454 * chunk handling. 1455 */ 1456 static enum sctp_disposition sctp_sf_do_unexpected_init( 1457 struct net *net, 1458 const struct sctp_endpoint *ep, 1459 const struct sctp_association *asoc, 1460 const union sctp_subtype type, 1461 void *arg, 1462 struct sctp_cmd_seq *commands) 1463 { 1464 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1465 struct sctp_unrecognized_param *unk_param; 1466 struct sctp_association *new_asoc; 1467 enum sctp_disposition retval; 1468 struct sctp_packet *packet; 1469 int len; 1470 1471 /* Update socket peer label if first association. */ 1472 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 1473 chunk->skb)) 1474 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1475 1476 /* 6.10 Bundling 1477 * An endpoint MUST NOT bundle INIT, INIT ACK or 1478 * SHUTDOWN COMPLETE with any other chunks. 1479 * 1480 * IG Section 2.11.2 1481 * Furthermore, we require that the receiver of an INIT chunk MUST 1482 * enforce these rules by silently discarding an arriving packet 1483 * with an INIT chunk that is bundled with other chunks. 1484 */ 1485 if (!chunk->singleton) 1486 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1487 1488 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1489 * Tag. 1490 */ 1491 if (chunk->sctp_hdr->vtag != 0) 1492 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1493 1494 /* Make sure that the INIT chunk has a valid length. 1495 * In this case, we generate a protocol violation since we have 1496 * an association established. 1497 */ 1498 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1499 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1500 commands); 1501 /* Grab the INIT header. */ 1502 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1503 1504 /* Tag the variable length parameters. */ 1505 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1506 1507 /* Verify the INIT chunk before processing it. */ 1508 err_chunk = NULL; 1509 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1510 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1511 &err_chunk)) { 1512 /* This chunk contains fatal error. It is to be discarded. 1513 * Send an ABORT, with causes if there is any. 1514 */ 1515 if (err_chunk) { 1516 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1517 (__u8 *)(err_chunk->chunk_hdr) + 1518 sizeof(struct sctp_chunkhdr), 1519 ntohs(err_chunk->chunk_hdr->length) - 1520 sizeof(struct sctp_chunkhdr)); 1521 1522 if (packet) { 1523 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1524 SCTP_PACKET(packet)); 1525 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1526 retval = SCTP_DISPOSITION_CONSUME; 1527 } else { 1528 retval = SCTP_DISPOSITION_NOMEM; 1529 } 1530 goto cleanup; 1531 } else { 1532 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1533 commands); 1534 } 1535 } 1536 1537 /* 1538 * Other parameters for the endpoint SHOULD be copied from the 1539 * existing parameters of the association (e.g. number of 1540 * outbound streams) into the INIT ACK and cookie. 1541 * FIXME: We are copying parameters from the endpoint not the 1542 * association. 1543 */ 1544 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1545 if (!new_asoc) 1546 goto nomem; 1547 1548 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1549 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1550 goto nomem; 1551 1552 /* In the outbound INIT ACK the endpoint MUST copy its current 1553 * Verification Tag and Peers Verification tag into a reserved 1554 * place (local tie-tag and per tie-tag) within the state cookie. 1555 */ 1556 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1557 (struct sctp_init_chunk *)chunk->chunk_hdr, 1558 GFP_ATOMIC)) 1559 goto nomem; 1560 1561 /* Make sure no new addresses are being added during the 1562 * restart. Do not do this check for COOKIE-WAIT state, 1563 * since there are no peer addresses to check against. 1564 * Upon return an ABORT will have been sent if needed. 1565 */ 1566 if (!sctp_state(asoc, COOKIE_WAIT)) { 1567 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1568 commands)) { 1569 retval = SCTP_DISPOSITION_CONSUME; 1570 goto nomem_retval; 1571 } 1572 } 1573 1574 sctp_tietags_populate(new_asoc, asoc); 1575 1576 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1577 1578 /* If there are errors need to be reported for unknown parameters, 1579 * make sure to reserve enough room in the INIT ACK for them. 1580 */ 1581 len = 0; 1582 if (err_chunk) { 1583 len = ntohs(err_chunk->chunk_hdr->length) - 1584 sizeof(struct sctp_chunkhdr); 1585 } 1586 1587 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1588 if (!repl) 1589 goto nomem; 1590 1591 /* If there are errors need to be reported for unknown parameters, 1592 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1593 * parameter. 1594 */ 1595 if (err_chunk) { 1596 /* Get the "Unrecognized parameter" parameter(s) out of the 1597 * ERROR chunk generated by sctp_verify_init(). Since the 1598 * error cause code for "unknown parameter" and the 1599 * "Unrecognized parameter" type is the same, we can 1600 * construct the parameters in INIT ACK by copying the 1601 * ERROR causes over. 1602 */ 1603 unk_param = (struct sctp_unrecognized_param *) 1604 ((__u8 *)(err_chunk->chunk_hdr) + 1605 sizeof(struct sctp_chunkhdr)); 1606 /* Replace the cause code with the "Unrecognized parameter" 1607 * parameter type. 1608 */ 1609 sctp_addto_chunk(repl, len, unk_param); 1610 } 1611 1612 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1613 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1614 1615 /* 1616 * Note: After sending out INIT ACK with the State Cookie parameter, 1617 * "Z" MUST NOT allocate any resources for this new association. 1618 * Otherwise, "Z" will be vulnerable to resource attacks. 1619 */ 1620 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1621 retval = SCTP_DISPOSITION_CONSUME; 1622 1623 return retval; 1624 1625 nomem: 1626 retval = SCTP_DISPOSITION_NOMEM; 1627 nomem_retval: 1628 if (new_asoc) 1629 sctp_association_free(new_asoc); 1630 cleanup: 1631 if (err_chunk) 1632 sctp_chunk_free(err_chunk); 1633 return retval; 1634 } 1635 1636 /* 1637 * Handle simultaneous INIT. 1638 * This means we started an INIT and then we got an INIT request from 1639 * our peer. 1640 * 1641 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1642 * This usually indicates an initialization collision, i.e., each 1643 * endpoint is attempting, at about the same time, to establish an 1644 * association with the other endpoint. 1645 * 1646 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1647 * endpoint MUST respond with an INIT ACK using the same parameters it 1648 * sent in its original INIT chunk (including its Verification Tag, 1649 * unchanged). These original parameters are combined with those from the 1650 * newly received INIT chunk. The endpoint shall also generate a State 1651 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1652 * INIT to calculate the State Cookie. 1653 * 1654 * After that, the endpoint MUST NOT change its state, the T1-init 1655 * timer shall be left running and the corresponding TCB MUST NOT be 1656 * destroyed. The normal procedures for handling State Cookies when 1657 * a TCB exists will resolve the duplicate INITs to a single association. 1658 * 1659 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1660 * its Tie-Tags with the Tag information of itself and its peer (see 1661 * section 5.2.2 for a description of the Tie-Tags). 1662 * 1663 * Verification Tag: Not explicit, but an INIT can not have a valid 1664 * verification tag, so we skip the check. 1665 * 1666 * Inputs 1667 * (endpoint, asoc, chunk) 1668 * 1669 * Outputs 1670 * (asoc, reply_msg, msg_up, timers, counters) 1671 * 1672 * The return value is the disposition of the chunk. 1673 */ 1674 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1675 struct net *net, 1676 const struct sctp_endpoint *ep, 1677 const struct sctp_association *asoc, 1678 const union sctp_subtype type, 1679 void *arg, 1680 struct sctp_cmd_seq *commands) 1681 { 1682 /* Call helper to do the real work for both simulataneous and 1683 * duplicate INIT chunk handling. 1684 */ 1685 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1686 } 1687 1688 /* 1689 * Handle duplicated INIT messages. These are usually delayed 1690 * restransmissions. 1691 * 1692 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1693 * COOKIE-ECHOED and COOKIE-WAIT 1694 * 1695 * Unless otherwise stated, upon reception of an unexpected INIT for 1696 * this association, the endpoint shall generate an INIT ACK with a 1697 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1698 * current Verification Tag and peer's Verification Tag into a reserved 1699 * place within the state cookie. We shall refer to these locations as 1700 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1701 * containing this INIT ACK MUST carry a Verification Tag value equal to 1702 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1703 * MUST contain a new Initiation Tag (randomly generated see Section 1704 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1705 * existing parameters of the association (e.g. number of outbound 1706 * streams) into the INIT ACK and cookie. 1707 * 1708 * After sending out the INIT ACK, the endpoint shall take no further 1709 * actions, i.e., the existing association, including its current state, 1710 * and the corresponding TCB MUST NOT be changed. 1711 * 1712 * Note: Only when a TCB exists and the association is not in a COOKIE- 1713 * WAIT state are the Tie-Tags populated. For a normal association INIT 1714 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1715 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1716 * State Cookie are populated as specified in section 5.2.1. 1717 * 1718 * Verification Tag: Not specified, but an INIT has no way of knowing 1719 * what the verification tag could be, so we ignore it. 1720 * 1721 * Inputs 1722 * (endpoint, asoc, chunk) 1723 * 1724 * Outputs 1725 * (asoc, reply_msg, msg_up, timers, counters) 1726 * 1727 * The return value is the disposition of the chunk. 1728 */ 1729 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1730 struct net *net, 1731 const struct sctp_endpoint *ep, 1732 const struct sctp_association *asoc, 1733 const union sctp_subtype type, 1734 void *arg, 1735 struct sctp_cmd_seq *commands) 1736 { 1737 /* Call helper to do the real work for both simulataneous and 1738 * duplicate INIT chunk handling. 1739 */ 1740 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1741 } 1742 1743 1744 /* 1745 * Unexpected INIT-ACK handler. 1746 * 1747 * Section 5.2.3 1748 * If an INIT ACK received by an endpoint in any state other than the 1749 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1750 * An unexpected INIT ACK usually indicates the processing of an old or 1751 * duplicated INIT chunk. 1752 */ 1753 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1754 struct net *net, 1755 const struct sctp_endpoint *ep, 1756 const struct sctp_association *asoc, 1757 const union sctp_subtype type, 1758 void *arg, 1759 struct sctp_cmd_seq *commands) 1760 { 1761 /* Per the above section, we'll discard the chunk if we have an 1762 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1763 */ 1764 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1765 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1766 else 1767 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1768 } 1769 1770 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1771 * 1772 * Section 5.2.4 1773 * A) In this case, the peer may have restarted. 1774 */ 1775 static enum sctp_disposition sctp_sf_do_dupcook_a( 1776 struct net *net, 1777 const struct sctp_endpoint *ep, 1778 const struct sctp_association *asoc, 1779 struct sctp_chunk *chunk, 1780 struct sctp_cmd_seq *commands, 1781 struct sctp_association *new_asoc) 1782 { 1783 struct sctp_init_chunk *peer_init; 1784 enum sctp_disposition disposition; 1785 struct sctp_ulpevent *ev; 1786 struct sctp_chunk *repl; 1787 struct sctp_chunk *err; 1788 1789 /* new_asoc is a brand-new association, so these are not yet 1790 * side effects--it is safe to run them here. 1791 */ 1792 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1793 1794 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1795 GFP_ATOMIC)) 1796 goto nomem; 1797 1798 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1799 goto nomem; 1800 1801 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1802 return SCTP_DISPOSITION_DISCARD; 1803 1804 /* Make sure no new addresses are being added during the 1805 * restart. Though this is a pretty complicated attack 1806 * since you'd have to get inside the cookie. 1807 */ 1808 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1809 return SCTP_DISPOSITION_CONSUME; 1810 1811 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1812 * the peer has restarted (Action A), it MUST NOT setup a new 1813 * association but instead resend the SHUTDOWN ACK and send an ERROR 1814 * chunk with a "Cookie Received while Shutting Down" error cause to 1815 * its peer. 1816 */ 1817 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1818 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1819 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1820 chunk, commands); 1821 if (SCTP_DISPOSITION_NOMEM == disposition) 1822 goto nomem; 1823 1824 err = sctp_make_op_error(asoc, chunk, 1825 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1826 NULL, 0, 0); 1827 if (err) 1828 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1829 SCTP_CHUNK(err)); 1830 1831 return SCTP_DISPOSITION_CONSUME; 1832 } 1833 1834 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1835 * data. Consider the optional choice of resending of this data. 1836 */ 1837 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1838 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1839 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1840 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1841 1842 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1843 * and ASCONF-ACK cache. 1844 */ 1845 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1846 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1847 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1848 1849 repl = sctp_make_cookie_ack(new_asoc, chunk); 1850 if (!repl) 1851 goto nomem; 1852 1853 /* Report association restart to upper layer. */ 1854 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1855 new_asoc->c.sinit_num_ostreams, 1856 new_asoc->c.sinit_max_instreams, 1857 NULL, GFP_ATOMIC); 1858 if (!ev) 1859 goto nomem_ev; 1860 1861 /* Update the content of current association. */ 1862 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1863 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1864 if (sctp_state(asoc, SHUTDOWN_PENDING) && 1865 (sctp_sstate(asoc->base.sk, CLOSING) || 1866 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1867 /* if were currently in SHUTDOWN_PENDING, but the socket 1868 * has been closed by user, don't transition to ESTABLISHED. 1869 * Instead trigger SHUTDOWN bundled with COOKIE_ACK. 1870 */ 1871 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1872 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1873 SCTP_ST_CHUNK(0), NULL, 1874 commands); 1875 } else { 1876 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1877 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1878 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1879 } 1880 return SCTP_DISPOSITION_CONSUME; 1881 1882 nomem_ev: 1883 sctp_chunk_free(repl); 1884 nomem: 1885 return SCTP_DISPOSITION_NOMEM; 1886 } 1887 1888 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1889 * 1890 * Section 5.2.4 1891 * B) In this case, both sides may be attempting to start an association 1892 * at about the same time but the peer endpoint started its INIT 1893 * after responding to the local endpoint's INIT 1894 */ 1895 /* This case represents an initialization collision. */ 1896 static enum sctp_disposition sctp_sf_do_dupcook_b( 1897 struct net *net, 1898 const struct sctp_endpoint *ep, 1899 const struct sctp_association *asoc, 1900 struct sctp_chunk *chunk, 1901 struct sctp_cmd_seq *commands, 1902 struct sctp_association *new_asoc) 1903 { 1904 struct sctp_init_chunk *peer_init; 1905 struct sctp_chunk *repl; 1906 1907 /* new_asoc is a brand-new association, so these are not yet 1908 * side effects--it is safe to run them here. 1909 */ 1910 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1911 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1912 GFP_ATOMIC)) 1913 goto nomem; 1914 1915 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1916 goto nomem; 1917 1918 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1919 return SCTP_DISPOSITION_DISCARD; 1920 1921 /* Update the content of current association. */ 1922 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1923 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1924 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1925 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1926 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1927 1928 repl = sctp_make_cookie_ack(new_asoc, chunk); 1929 if (!repl) 1930 goto nomem; 1931 1932 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1933 1934 /* RFC 2960 5.1 Normal Establishment of an Association 1935 * 1936 * D) IMPLEMENTATION NOTE: An implementation may choose to 1937 * send the Communication Up notification to the SCTP user 1938 * upon reception of a valid COOKIE ECHO chunk. 1939 * 1940 * Sadly, this needs to be implemented as a side-effect, because 1941 * we are not guaranteed to have set the association id of the real 1942 * association and so these notifications need to be delayed until 1943 * the association id is allocated. 1944 */ 1945 1946 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1947 1948 /* Sockets API Draft Section 5.3.1.6 1949 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1950 * delivers this notification to inform the application that of the 1951 * peers requested adaptation layer. 1952 * 1953 * This also needs to be done as a side effect for the same reason as 1954 * above. 1955 */ 1956 if (asoc->peer.adaptation_ind) 1957 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1958 1959 if (!asoc->peer.auth_capable) 1960 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 1961 1962 return SCTP_DISPOSITION_CONSUME; 1963 1964 nomem: 1965 return SCTP_DISPOSITION_NOMEM; 1966 } 1967 1968 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1969 * 1970 * Section 5.2.4 1971 * C) In this case, the local endpoint's cookie has arrived late. 1972 * Before it arrived, the local endpoint sent an INIT and received an 1973 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1974 * but a new tag of its own. 1975 */ 1976 /* This case represents an initialization collision. */ 1977 static enum sctp_disposition sctp_sf_do_dupcook_c( 1978 struct net *net, 1979 const struct sctp_endpoint *ep, 1980 const struct sctp_association *asoc, 1981 struct sctp_chunk *chunk, 1982 struct sctp_cmd_seq *commands, 1983 struct sctp_association *new_asoc) 1984 { 1985 /* The cookie should be silently discarded. 1986 * The endpoint SHOULD NOT change states and should leave 1987 * any timers running. 1988 */ 1989 return SCTP_DISPOSITION_DISCARD; 1990 } 1991 1992 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1993 * 1994 * Section 5.2.4 1995 * 1996 * D) When both local and remote tags match the endpoint should always 1997 * enter the ESTABLISHED state, if it has not already done so. 1998 */ 1999 /* This case represents an initialization collision. */ 2000 static enum sctp_disposition sctp_sf_do_dupcook_d( 2001 struct net *net, 2002 const struct sctp_endpoint *ep, 2003 const struct sctp_association *asoc, 2004 struct sctp_chunk *chunk, 2005 struct sctp_cmd_seq *commands, 2006 struct sctp_association *new_asoc) 2007 { 2008 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2009 struct sctp_chunk *repl; 2010 2011 /* Clarification from Implementor's Guide: 2012 * D) When both local and remote tags match the endpoint should 2013 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2014 * It should stop any cookie timer that may be running and send 2015 * a COOKIE ACK. 2016 */ 2017 2018 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2019 return SCTP_DISPOSITION_DISCARD; 2020 2021 /* Don't accidentally move back into established state. */ 2022 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2023 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2024 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2025 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2026 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2027 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2028 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2029 SCTP_NULL()); 2030 2031 /* RFC 2960 5.1 Normal Establishment of an Association 2032 * 2033 * D) IMPLEMENTATION NOTE: An implementation may choose 2034 * to send the Communication Up notification to the 2035 * SCTP user upon reception of a valid COOKIE 2036 * ECHO chunk. 2037 */ 2038 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2039 SCTP_COMM_UP, 0, 2040 asoc->c.sinit_num_ostreams, 2041 asoc->c.sinit_max_instreams, 2042 NULL, GFP_ATOMIC); 2043 if (!ev) 2044 goto nomem; 2045 2046 /* Sockets API Draft Section 5.3.1.6 2047 * When a peer sends a Adaptation Layer Indication parameter, 2048 * SCTP delivers this notification to inform the application 2049 * that of the peers requested adaptation layer. 2050 */ 2051 if (asoc->peer.adaptation_ind) { 2052 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2053 GFP_ATOMIC); 2054 if (!ai_ev) 2055 goto nomem; 2056 2057 } 2058 2059 if (!asoc->peer.auth_capable) { 2060 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2061 SCTP_AUTH_NO_AUTH, 2062 GFP_ATOMIC); 2063 if (!auth_ev) 2064 goto nomem; 2065 } 2066 } 2067 2068 repl = sctp_make_cookie_ack(asoc, chunk); 2069 if (!repl) 2070 goto nomem; 2071 2072 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2073 2074 if (ev) 2075 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2076 SCTP_ULPEVENT(ev)); 2077 if (ai_ev) 2078 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2079 SCTP_ULPEVENT(ai_ev)); 2080 if (auth_ev) 2081 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2082 SCTP_ULPEVENT(auth_ev)); 2083 2084 return SCTP_DISPOSITION_CONSUME; 2085 2086 nomem: 2087 if (auth_ev) 2088 sctp_ulpevent_free(auth_ev); 2089 if (ai_ev) 2090 sctp_ulpevent_free(ai_ev); 2091 if (ev) 2092 sctp_ulpevent_free(ev); 2093 return SCTP_DISPOSITION_NOMEM; 2094 } 2095 2096 /* 2097 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2098 * chunk was retransmitted and then delayed in the network. 2099 * 2100 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2101 * 2102 * Verification Tag: None. Do cookie validation. 2103 * 2104 * Inputs 2105 * (endpoint, asoc, chunk) 2106 * 2107 * Outputs 2108 * (asoc, reply_msg, msg_up, timers, counters) 2109 * 2110 * The return value is the disposition of the chunk. 2111 */ 2112 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2113 struct net *net, 2114 const struct sctp_endpoint *ep, 2115 const struct sctp_association *asoc, 2116 const union sctp_subtype type, 2117 void *arg, 2118 struct sctp_cmd_seq *commands) 2119 { 2120 struct sctp_association *new_asoc; 2121 struct sctp_chunk *chunk = arg; 2122 enum sctp_disposition retval; 2123 struct sctp_chunk *err_chk_p; 2124 int error = 0; 2125 char action; 2126 2127 /* Make sure that the chunk has a valid length from the protocol 2128 * perspective. In this case check to make sure we have at least 2129 * enough for the chunk header. Cookie length verification is 2130 * done later. 2131 */ 2132 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2133 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2134 commands); 2135 2136 /* "Decode" the chunk. We have no optional parameters so we 2137 * are in good shape. 2138 */ 2139 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2140 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2141 sizeof(struct sctp_chunkhdr))) 2142 goto nomem; 2143 2144 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2145 * of a duplicate COOKIE ECHO match the Verification Tags of the 2146 * current association, consider the State Cookie valid even if 2147 * the lifespan is exceeded. 2148 */ 2149 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2150 &err_chk_p); 2151 2152 /* FIXME: 2153 * If the re-build failed, what is the proper error path 2154 * from here? 2155 * 2156 * [We should abort the association. --piggy] 2157 */ 2158 if (!new_asoc) { 2159 /* FIXME: Several errors are possible. A bad cookie should 2160 * be silently discarded, but think about logging it too. 2161 */ 2162 switch (error) { 2163 case -SCTP_IERROR_NOMEM: 2164 goto nomem; 2165 2166 case -SCTP_IERROR_STALE_COOKIE: 2167 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2168 err_chk_p); 2169 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2170 case -SCTP_IERROR_BAD_SIG: 2171 default: 2172 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2173 } 2174 } 2175 2176 /* Update socket peer label if first association. */ 2177 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 2178 chunk->skb)) 2179 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2180 2181 /* Set temp so that it won't be added into hashtable */ 2182 new_asoc->temp = 1; 2183 2184 /* Compare the tie_tag in cookie with the verification tag of 2185 * current association. 2186 */ 2187 action = sctp_tietags_compare(new_asoc, asoc); 2188 2189 switch (action) { 2190 case 'A': /* Association restart. */ 2191 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2192 new_asoc); 2193 break; 2194 2195 case 'B': /* Collision case B. */ 2196 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2197 new_asoc); 2198 break; 2199 2200 case 'C': /* Collision case C. */ 2201 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2202 new_asoc); 2203 break; 2204 2205 case 'D': /* Collision case D. */ 2206 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2207 new_asoc); 2208 break; 2209 2210 default: /* Discard packet for all others. */ 2211 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2212 break; 2213 } 2214 2215 /* Delete the tempory new association. */ 2216 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2217 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2218 2219 /* Restore association pointer to provide SCTP command interpeter 2220 * with a valid context in case it needs to manipulate 2221 * the queues */ 2222 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2223 SCTP_ASOC((struct sctp_association *)asoc)); 2224 2225 return retval; 2226 2227 nomem: 2228 return SCTP_DISPOSITION_NOMEM; 2229 } 2230 2231 /* 2232 * Process an ABORT. (SHUTDOWN-PENDING state) 2233 * 2234 * See sctp_sf_do_9_1_abort(). 2235 */ 2236 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2237 struct net *net, 2238 const struct sctp_endpoint *ep, 2239 const struct sctp_association *asoc, 2240 const union sctp_subtype type, 2241 void *arg, 2242 struct sctp_cmd_seq *commands) 2243 { 2244 struct sctp_chunk *chunk = arg; 2245 2246 if (!sctp_vtag_verify_either(chunk, asoc)) 2247 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2248 2249 /* Make sure that the ABORT chunk has a valid length. 2250 * Since this is an ABORT chunk, we have to discard it 2251 * because of the following text: 2252 * RFC 2960, Section 3.3.7 2253 * If an endpoint receives an ABORT with a format error or for an 2254 * association that doesn't exist, it MUST silently discard it. 2255 * Because the length is "invalid", we can't really discard just 2256 * as we do not know its true length. So, to be safe, discard the 2257 * packet. 2258 */ 2259 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2260 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2261 2262 /* ADD-IP: Special case for ABORT chunks 2263 * F4) One special consideration is that ABORT Chunks arriving 2264 * destined to the IP address being deleted MUST be 2265 * ignored (see Section 5.3.1 for further details). 2266 */ 2267 if (SCTP_ADDR_DEL == 2268 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2269 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2270 2271 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2272 } 2273 2274 /* 2275 * Process an ABORT. (SHUTDOWN-SENT state) 2276 * 2277 * See sctp_sf_do_9_1_abort(). 2278 */ 2279 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2280 struct net *net, 2281 const struct sctp_endpoint *ep, 2282 const struct sctp_association *asoc, 2283 const union sctp_subtype type, 2284 void *arg, 2285 struct sctp_cmd_seq *commands) 2286 { 2287 struct sctp_chunk *chunk = arg; 2288 2289 if (!sctp_vtag_verify_either(chunk, asoc)) 2290 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2291 2292 /* Make sure that the ABORT chunk has a valid length. 2293 * Since this is an ABORT chunk, we have to discard it 2294 * because of the following text: 2295 * RFC 2960, Section 3.3.7 2296 * If an endpoint receives an ABORT with a format error or for an 2297 * association that doesn't exist, it MUST silently discard it. 2298 * Because the length is "invalid", we can't really discard just 2299 * as we do not know its true length. So, to be safe, discard the 2300 * packet. 2301 */ 2302 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2303 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2304 2305 /* ADD-IP: Special case for ABORT chunks 2306 * F4) One special consideration is that ABORT Chunks arriving 2307 * destined to the IP address being deleted MUST be 2308 * ignored (see Section 5.3.1 for further details). 2309 */ 2310 if (SCTP_ADDR_DEL == 2311 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2312 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2313 2314 /* Stop the T2-shutdown timer. */ 2315 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2316 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2317 2318 /* Stop the T5-shutdown guard timer. */ 2319 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2320 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2321 2322 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2323 } 2324 2325 /* 2326 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2327 * 2328 * See sctp_sf_do_9_1_abort(). 2329 */ 2330 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2331 struct net *net, 2332 const struct sctp_endpoint *ep, 2333 const struct sctp_association *asoc, 2334 const union sctp_subtype type, 2335 void *arg, 2336 struct sctp_cmd_seq *commands) 2337 { 2338 /* The same T2 timer, so we should be able to use 2339 * common function with the SHUTDOWN-SENT state. 2340 */ 2341 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2342 } 2343 2344 /* 2345 * Handle an Error received in COOKIE_ECHOED state. 2346 * 2347 * Only handle the error type of stale COOKIE Error, the other errors will 2348 * be ignored. 2349 * 2350 * Inputs 2351 * (endpoint, asoc, chunk) 2352 * 2353 * Outputs 2354 * (asoc, reply_msg, msg_up, timers, counters) 2355 * 2356 * The return value is the disposition of the chunk. 2357 */ 2358 enum sctp_disposition sctp_sf_cookie_echoed_err( 2359 struct net *net, 2360 const struct sctp_endpoint *ep, 2361 const struct sctp_association *asoc, 2362 const union sctp_subtype type, 2363 void *arg, 2364 struct sctp_cmd_seq *commands) 2365 { 2366 struct sctp_chunk *chunk = arg; 2367 struct sctp_errhdr *err; 2368 2369 if (!sctp_vtag_verify(chunk, asoc)) 2370 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2371 2372 /* Make sure that the ERROR chunk has a valid length. 2373 * The parameter walking depends on this as well. 2374 */ 2375 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2376 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2377 commands); 2378 2379 /* Process the error here */ 2380 /* FUTURE FIXME: When PR-SCTP related and other optional 2381 * parms are emitted, this will have to change to handle multiple 2382 * errors. 2383 */ 2384 sctp_walk_errors(err, chunk->chunk_hdr) { 2385 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2386 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2387 arg, commands); 2388 } 2389 2390 /* It is possible to have malformed error causes, and that 2391 * will cause us to end the walk early. However, since 2392 * we are discarding the packet, there should be no adverse 2393 * affects. 2394 */ 2395 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2396 } 2397 2398 /* 2399 * Handle a Stale COOKIE Error 2400 * 2401 * Section: 5.2.6 Handle Stale COOKIE Error 2402 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2403 * one of the following three alternatives. 2404 * ... 2405 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2406 * Preservative parameter requesting an extension to the lifetime of 2407 * the State Cookie. When calculating the time extension, an 2408 * implementation SHOULD use the RTT information measured based on the 2409 * previous COOKIE ECHO / ERROR exchange, and should add no more 2410 * than 1 second beyond the measured RTT, due to long State Cookie 2411 * lifetimes making the endpoint more subject to a replay attack. 2412 * 2413 * Verification Tag: Not explicit, but safe to ignore. 2414 * 2415 * Inputs 2416 * (endpoint, asoc, chunk) 2417 * 2418 * Outputs 2419 * (asoc, reply_msg, msg_up, timers, counters) 2420 * 2421 * The return value is the disposition of the chunk. 2422 */ 2423 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2424 struct net *net, 2425 const struct sctp_endpoint *ep, 2426 const struct sctp_association *asoc, 2427 const union sctp_subtype type, 2428 void *arg, 2429 struct sctp_cmd_seq *commands) 2430 { 2431 int attempts = asoc->init_err_counter + 1; 2432 struct sctp_chunk *chunk = arg, *reply; 2433 struct sctp_cookie_preserve_param bht; 2434 struct sctp_bind_addr *bp; 2435 struct sctp_errhdr *err; 2436 u32 stale; 2437 2438 if (attempts > asoc->max_init_attempts) { 2439 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2440 SCTP_ERROR(ETIMEDOUT)); 2441 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2442 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2443 return SCTP_DISPOSITION_DELETE_TCB; 2444 } 2445 2446 err = (struct sctp_errhdr *)(chunk->skb->data); 2447 2448 /* When calculating the time extension, an implementation 2449 * SHOULD use the RTT information measured based on the 2450 * previous COOKIE ECHO / ERROR exchange, and should add no 2451 * more than 1 second beyond the measured RTT, due to long 2452 * State Cookie lifetimes making the endpoint more subject to 2453 * a replay attack. 2454 * Measure of Staleness's unit is usec. (1/1000000 sec) 2455 * Suggested Cookie Life-span Increment's unit is msec. 2456 * (1/1000 sec) 2457 * In general, if you use the suggested cookie life, the value 2458 * found in the field of measure of staleness should be doubled 2459 * to give ample time to retransmit the new cookie and thus 2460 * yield a higher probability of success on the reattempt. 2461 */ 2462 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2463 stale = (stale * 2) / 1000; 2464 2465 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2466 bht.param_hdr.length = htons(sizeof(bht)); 2467 bht.lifespan_increment = htonl(stale); 2468 2469 /* Build that new INIT chunk. */ 2470 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2471 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2472 if (!reply) 2473 goto nomem; 2474 2475 sctp_addto_chunk(reply, sizeof(bht), &bht); 2476 2477 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2478 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2479 2480 /* Stop pending T3-rtx and heartbeat timers */ 2481 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2482 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2483 2484 /* Delete non-primary peer ip addresses since we are transitioning 2485 * back to the COOKIE-WAIT state 2486 */ 2487 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2488 2489 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2490 * resend 2491 */ 2492 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2493 SCTP_TRANSPORT(asoc->peer.primary_path)); 2494 2495 /* Cast away the const modifier, as we want to just 2496 * rerun it through as a sideffect. 2497 */ 2498 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2499 2500 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2501 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2502 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2503 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2504 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2505 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2506 2507 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2508 2509 return SCTP_DISPOSITION_CONSUME; 2510 2511 nomem: 2512 return SCTP_DISPOSITION_NOMEM; 2513 } 2514 2515 /* 2516 * Process an ABORT. 2517 * 2518 * Section: 9.1 2519 * After checking the Verification Tag, the receiving endpoint shall 2520 * remove the association from its record, and shall report the 2521 * termination to its upper layer. 2522 * 2523 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2524 * B) Rules for packet carrying ABORT: 2525 * 2526 * - The endpoint shall always fill in the Verification Tag field of the 2527 * outbound packet with the destination endpoint's tag value if it 2528 * is known. 2529 * 2530 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2531 * MUST follow the procedure described in Section 8.4. 2532 * 2533 * - The receiver MUST accept the packet if the Verification Tag 2534 * matches either its own tag, OR the tag of its peer. Otherwise, the 2535 * receiver MUST silently discard the packet and take no further 2536 * action. 2537 * 2538 * Inputs 2539 * (endpoint, asoc, chunk) 2540 * 2541 * Outputs 2542 * (asoc, reply_msg, msg_up, timers, counters) 2543 * 2544 * The return value is the disposition of the chunk. 2545 */ 2546 enum sctp_disposition sctp_sf_do_9_1_abort( 2547 struct net *net, 2548 const struct sctp_endpoint *ep, 2549 const struct sctp_association *asoc, 2550 const union sctp_subtype type, 2551 void *arg, 2552 struct sctp_cmd_seq *commands) 2553 { 2554 struct sctp_chunk *chunk = arg; 2555 2556 if (!sctp_vtag_verify_either(chunk, asoc)) 2557 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2558 2559 /* Make sure that the ABORT chunk has a valid length. 2560 * Since this is an ABORT chunk, we have to discard it 2561 * because of the following text: 2562 * RFC 2960, Section 3.3.7 2563 * If an endpoint receives an ABORT with a format error or for an 2564 * association that doesn't exist, it MUST silently discard it. 2565 * Because the length is "invalid", we can't really discard just 2566 * as we do not know its true length. So, to be safe, discard the 2567 * packet. 2568 */ 2569 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2570 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2571 2572 /* ADD-IP: Special case for ABORT chunks 2573 * F4) One special consideration is that ABORT Chunks arriving 2574 * destined to the IP address being deleted MUST be 2575 * ignored (see Section 5.3.1 for further details). 2576 */ 2577 if (SCTP_ADDR_DEL == 2578 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2579 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2580 2581 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2582 } 2583 2584 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2585 struct net *net, 2586 const struct sctp_endpoint *ep, 2587 const struct sctp_association *asoc, 2588 const union sctp_subtype type, 2589 void *arg, 2590 struct sctp_cmd_seq *commands) 2591 { 2592 __be16 error = SCTP_ERROR_NO_ERROR; 2593 struct sctp_chunk *chunk = arg; 2594 unsigned int len; 2595 2596 /* See if we have an error cause code in the chunk. */ 2597 len = ntohs(chunk->chunk_hdr->length); 2598 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2599 struct sctp_errhdr *err; 2600 2601 sctp_walk_errors(err, chunk->chunk_hdr); 2602 if ((void *)err != (void *)chunk->chunk_end) 2603 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 2604 commands); 2605 2606 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2607 } 2608 2609 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2610 /* ASSOC_FAILED will DELETE_TCB. */ 2611 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2612 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2613 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2614 2615 return SCTP_DISPOSITION_ABORT; 2616 } 2617 2618 /* 2619 * Process an ABORT. (COOKIE-WAIT state) 2620 * 2621 * See sctp_sf_do_9_1_abort() above. 2622 */ 2623 enum sctp_disposition sctp_sf_cookie_wait_abort( 2624 struct net *net, 2625 const struct sctp_endpoint *ep, 2626 const struct sctp_association *asoc, 2627 const union sctp_subtype type, 2628 void *arg, 2629 struct sctp_cmd_seq *commands) 2630 { 2631 __be16 error = SCTP_ERROR_NO_ERROR; 2632 struct sctp_chunk *chunk = arg; 2633 unsigned int len; 2634 2635 if (!sctp_vtag_verify_either(chunk, asoc)) 2636 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2637 2638 /* Make sure that the ABORT chunk has a valid length. 2639 * Since this is an ABORT chunk, we have to discard it 2640 * because of the following text: 2641 * RFC 2960, Section 3.3.7 2642 * If an endpoint receives an ABORT with a format error or for an 2643 * association that doesn't exist, it MUST silently discard it. 2644 * Because the length is "invalid", we can't really discard just 2645 * as we do not know its true length. So, to be safe, discard the 2646 * packet. 2647 */ 2648 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2649 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2650 2651 /* See if we have an error cause code in the chunk. */ 2652 len = ntohs(chunk->chunk_hdr->length); 2653 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2654 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2655 2656 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2657 chunk->transport); 2658 } 2659 2660 /* 2661 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2662 */ 2663 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2664 struct net *net, 2665 const struct sctp_endpoint *ep, 2666 const struct sctp_association *asoc, 2667 const union sctp_subtype type, 2668 void *arg, 2669 struct sctp_cmd_seq *commands) 2670 { 2671 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2672 ENOPROTOOPT, asoc, 2673 (struct sctp_transport *)arg); 2674 } 2675 2676 /* 2677 * Process an ABORT. (COOKIE-ECHOED state) 2678 */ 2679 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2680 struct net *net, 2681 const struct sctp_endpoint *ep, 2682 const struct sctp_association *asoc, 2683 const union sctp_subtype type, 2684 void *arg, 2685 struct sctp_cmd_seq *commands) 2686 { 2687 /* There is a single T1 timer, so we should be able to use 2688 * common function with the COOKIE-WAIT state. 2689 */ 2690 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2691 } 2692 2693 /* 2694 * Stop T1 timer and abort association with "INIT failed". 2695 * 2696 * This is common code called by several sctp_sf_*_abort() functions above. 2697 */ 2698 static enum sctp_disposition sctp_stop_t1_and_abort( 2699 struct net *net, 2700 struct sctp_cmd_seq *commands, 2701 __be16 error, int sk_err, 2702 const struct sctp_association *asoc, 2703 struct sctp_transport *transport) 2704 { 2705 pr_debug("%s: ABORT received (INIT)\n", __func__); 2706 2707 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2708 SCTP_STATE(SCTP_STATE_CLOSED)); 2709 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2710 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2711 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2712 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2713 /* CMD_INIT_FAILED will DELETE_TCB. */ 2714 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2715 SCTP_PERR(error)); 2716 2717 return SCTP_DISPOSITION_ABORT; 2718 } 2719 2720 /* 2721 * sctp_sf_do_9_2_shut 2722 * 2723 * Section: 9.2 2724 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2725 * - enter the SHUTDOWN-RECEIVED state, 2726 * 2727 * - stop accepting new data from its SCTP user 2728 * 2729 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2730 * that all its outstanding DATA chunks have been received by the 2731 * SHUTDOWN sender. 2732 * 2733 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2734 * send a SHUTDOWN in response to a ULP request. And should discard 2735 * subsequent SHUTDOWN chunks. 2736 * 2737 * If there are still outstanding DATA chunks left, the SHUTDOWN 2738 * receiver shall continue to follow normal data transmission 2739 * procedures defined in Section 6 until all outstanding DATA chunks 2740 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2741 * new data from its SCTP user. 2742 * 2743 * Verification Tag: 8.5 Verification Tag [Normal verification] 2744 * 2745 * Inputs 2746 * (endpoint, asoc, chunk) 2747 * 2748 * Outputs 2749 * (asoc, reply_msg, msg_up, timers, counters) 2750 * 2751 * The return value is the disposition of the chunk. 2752 */ 2753 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2754 struct net *net, 2755 const struct sctp_endpoint *ep, 2756 const struct sctp_association *asoc, 2757 const union sctp_subtype type, 2758 void *arg, 2759 struct sctp_cmd_seq *commands) 2760 { 2761 enum sctp_disposition disposition; 2762 struct sctp_chunk *chunk = arg; 2763 struct sctp_shutdownhdr *sdh; 2764 struct sctp_ulpevent *ev; 2765 __u32 ctsn; 2766 2767 if (!sctp_vtag_verify(chunk, asoc)) 2768 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2769 2770 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2771 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2772 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2773 commands); 2774 2775 /* Convert the elaborate header. */ 2776 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2777 skb_pull(chunk->skb, sizeof(*sdh)); 2778 chunk->subh.shutdown_hdr = sdh; 2779 ctsn = ntohl(sdh->cum_tsn_ack); 2780 2781 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2782 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2783 asoc->ctsn_ack_point); 2784 2785 return SCTP_DISPOSITION_DISCARD; 2786 } 2787 2788 /* If Cumulative TSN Ack beyond the max tsn currently 2789 * send, terminating the association and respond to the 2790 * sender with an ABORT. 2791 */ 2792 if (!TSN_lt(ctsn, asoc->next_tsn)) 2793 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2794 2795 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2796 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2797 * inform the application that it should cease sending data. 2798 */ 2799 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2800 if (!ev) { 2801 disposition = SCTP_DISPOSITION_NOMEM; 2802 goto out; 2803 } 2804 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2805 2806 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2807 * - enter the SHUTDOWN-RECEIVED state, 2808 * - stop accepting new data from its SCTP user 2809 * 2810 * [This is implicit in the new state.] 2811 */ 2812 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2813 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2814 disposition = SCTP_DISPOSITION_CONSUME; 2815 2816 if (sctp_outq_is_empty(&asoc->outqueue)) { 2817 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2818 arg, commands); 2819 } 2820 2821 if (SCTP_DISPOSITION_NOMEM == disposition) 2822 goto out; 2823 2824 /* - verify, by checking the Cumulative TSN Ack field of the 2825 * chunk, that all its outstanding DATA chunks have been 2826 * received by the SHUTDOWN sender. 2827 */ 2828 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2829 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2830 2831 out: 2832 return disposition; 2833 } 2834 2835 /* 2836 * sctp_sf_do_9_2_shut_ctsn 2837 * 2838 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2839 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2840 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2841 * MUST be processed. 2842 */ 2843 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2844 struct net *net, 2845 const struct sctp_endpoint *ep, 2846 const struct sctp_association *asoc, 2847 const union sctp_subtype type, 2848 void *arg, 2849 struct sctp_cmd_seq *commands) 2850 { 2851 struct sctp_chunk *chunk = arg; 2852 struct sctp_shutdownhdr *sdh; 2853 __u32 ctsn; 2854 2855 if (!sctp_vtag_verify(chunk, asoc)) 2856 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2857 2858 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2859 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2860 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2861 commands); 2862 2863 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2864 ctsn = ntohl(sdh->cum_tsn_ack); 2865 2866 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2867 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2868 asoc->ctsn_ack_point); 2869 2870 return SCTP_DISPOSITION_DISCARD; 2871 } 2872 2873 /* If Cumulative TSN Ack beyond the max tsn currently 2874 * send, terminating the association and respond to the 2875 * sender with an ABORT. 2876 */ 2877 if (!TSN_lt(ctsn, asoc->next_tsn)) 2878 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2879 2880 /* verify, by checking the Cumulative TSN Ack field of the 2881 * chunk, that all its outstanding DATA chunks have been 2882 * received by the SHUTDOWN sender. 2883 */ 2884 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2885 SCTP_BE32(sdh->cum_tsn_ack)); 2886 2887 return SCTP_DISPOSITION_CONSUME; 2888 } 2889 2890 /* RFC 2960 9.2 2891 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2892 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2893 * transport addresses (either in the IP addresses or in the INIT chunk) 2894 * that belong to this association, it should discard the INIT chunk and 2895 * retransmit the SHUTDOWN ACK chunk. 2896 */ 2897 enum sctp_disposition sctp_sf_do_9_2_reshutack( 2898 struct net *net, 2899 const struct sctp_endpoint *ep, 2900 const struct sctp_association *asoc, 2901 const union sctp_subtype type, 2902 void *arg, 2903 struct sctp_cmd_seq *commands) 2904 { 2905 struct sctp_chunk *chunk = arg; 2906 struct sctp_chunk *reply; 2907 2908 /* Make sure that the chunk has a valid length */ 2909 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2910 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2911 commands); 2912 2913 /* Since we are not going to really process this INIT, there 2914 * is no point in verifying chunk boundries. Just generate 2915 * the SHUTDOWN ACK. 2916 */ 2917 reply = sctp_make_shutdown_ack(asoc, chunk); 2918 if (NULL == reply) 2919 goto nomem; 2920 2921 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2922 * the T2-SHUTDOWN timer. 2923 */ 2924 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2925 2926 /* and restart the T2-shutdown timer. */ 2927 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2928 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2929 2930 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2931 2932 return SCTP_DISPOSITION_CONSUME; 2933 nomem: 2934 return SCTP_DISPOSITION_NOMEM; 2935 } 2936 2937 /* 2938 * sctp_sf_do_ecn_cwr 2939 * 2940 * Section: Appendix A: Explicit Congestion Notification 2941 * 2942 * CWR: 2943 * 2944 * RFC 2481 details a specific bit for a sender to send in the header of 2945 * its next outbound TCP segment to indicate to its peer that it has 2946 * reduced its congestion window. This is termed the CWR bit. For 2947 * SCTP the same indication is made by including the CWR chunk. 2948 * This chunk contains one data element, i.e. the TSN number that 2949 * was sent in the ECNE chunk. This element represents the lowest 2950 * TSN number in the datagram that was originally marked with the 2951 * CE bit. 2952 * 2953 * Verification Tag: 8.5 Verification Tag [Normal verification] 2954 * Inputs 2955 * (endpoint, asoc, chunk) 2956 * 2957 * Outputs 2958 * (asoc, reply_msg, msg_up, timers, counters) 2959 * 2960 * The return value is the disposition of the chunk. 2961 */ 2962 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 2963 const struct sctp_endpoint *ep, 2964 const struct sctp_association *asoc, 2965 const union sctp_subtype type, 2966 void *arg, 2967 struct sctp_cmd_seq *commands) 2968 { 2969 struct sctp_chunk *chunk = arg; 2970 struct sctp_cwrhdr *cwr; 2971 u32 lowest_tsn; 2972 2973 if (!sctp_vtag_verify(chunk, asoc)) 2974 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2975 2976 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 2977 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2978 commands); 2979 2980 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 2981 skb_pull(chunk->skb, sizeof(*cwr)); 2982 2983 lowest_tsn = ntohl(cwr->lowest_tsn); 2984 2985 /* Does this CWR ack the last sent congestion notification? */ 2986 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2987 /* Stop sending ECNE. */ 2988 sctp_add_cmd_sf(commands, 2989 SCTP_CMD_ECN_CWR, 2990 SCTP_U32(lowest_tsn)); 2991 } 2992 return SCTP_DISPOSITION_CONSUME; 2993 } 2994 2995 /* 2996 * sctp_sf_do_ecne 2997 * 2998 * Section: Appendix A: Explicit Congestion Notification 2999 * 3000 * ECN-Echo 3001 * 3002 * RFC 2481 details a specific bit for a receiver to send back in its 3003 * TCP acknowledgements to notify the sender of the Congestion 3004 * Experienced (CE) bit having arrived from the network. For SCTP this 3005 * same indication is made by including the ECNE chunk. This chunk 3006 * contains one data element, i.e. the lowest TSN associated with the IP 3007 * datagram marked with the CE bit..... 3008 * 3009 * Verification Tag: 8.5 Verification Tag [Normal verification] 3010 * Inputs 3011 * (endpoint, asoc, chunk) 3012 * 3013 * Outputs 3014 * (asoc, reply_msg, msg_up, timers, counters) 3015 * 3016 * The return value is the disposition of the chunk. 3017 */ 3018 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3019 const struct sctp_endpoint *ep, 3020 const struct sctp_association *asoc, 3021 const union sctp_subtype type, 3022 void *arg, struct sctp_cmd_seq *commands) 3023 { 3024 struct sctp_chunk *chunk = arg; 3025 struct sctp_ecnehdr *ecne; 3026 3027 if (!sctp_vtag_verify(chunk, asoc)) 3028 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3029 3030 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3031 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3032 commands); 3033 3034 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3035 skb_pull(chunk->skb, sizeof(*ecne)); 3036 3037 /* If this is a newer ECNE than the last CWR packet we sent out */ 3038 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3039 SCTP_U32(ntohl(ecne->lowest_tsn))); 3040 3041 return SCTP_DISPOSITION_CONSUME; 3042 } 3043 3044 /* 3045 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3046 * 3047 * The SCTP endpoint MUST always acknowledge the reception of each valid 3048 * DATA chunk. 3049 * 3050 * The guidelines on delayed acknowledgement algorithm specified in 3051 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3052 * acknowledgement SHOULD be generated for at least every second packet 3053 * (not every second DATA chunk) received, and SHOULD be generated within 3054 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3055 * situations it may be beneficial for an SCTP transmitter to be more 3056 * conservative than the algorithms detailed in this document allow. 3057 * However, an SCTP transmitter MUST NOT be more aggressive than the 3058 * following algorithms allow. 3059 * 3060 * A SCTP receiver MUST NOT generate more than one SACK for every 3061 * incoming packet, other than to update the offered window as the 3062 * receiving application consumes new data. 3063 * 3064 * Verification Tag: 8.5 Verification Tag [Normal verification] 3065 * 3066 * Inputs 3067 * (endpoint, asoc, chunk) 3068 * 3069 * Outputs 3070 * (asoc, reply_msg, msg_up, timers, counters) 3071 * 3072 * The return value is the disposition of the chunk. 3073 */ 3074 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3075 const struct sctp_endpoint *ep, 3076 const struct sctp_association *asoc, 3077 const union sctp_subtype type, 3078 void *arg, 3079 struct sctp_cmd_seq *commands) 3080 { 3081 union sctp_arg force = SCTP_NOFORCE(); 3082 struct sctp_chunk *chunk = arg; 3083 int error; 3084 3085 if (!sctp_vtag_verify(chunk, asoc)) { 3086 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3087 SCTP_NULL()); 3088 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3089 } 3090 3091 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3092 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3093 commands); 3094 3095 error = sctp_eat_data(asoc, chunk, commands); 3096 switch (error) { 3097 case SCTP_IERROR_NO_ERROR: 3098 break; 3099 case SCTP_IERROR_HIGH_TSN: 3100 case SCTP_IERROR_BAD_STREAM: 3101 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3102 goto discard_noforce; 3103 case SCTP_IERROR_DUP_TSN: 3104 case SCTP_IERROR_IGNORE_TSN: 3105 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3106 goto discard_force; 3107 case SCTP_IERROR_NO_DATA: 3108 return SCTP_DISPOSITION_ABORT; 3109 case SCTP_IERROR_PROTO_VIOLATION: 3110 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3111 (u8 *)chunk->subh.data_hdr, 3112 sctp_datahdr_len(&asoc->stream)); 3113 default: 3114 BUG(); 3115 } 3116 3117 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3118 force = SCTP_FORCE(); 3119 3120 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3121 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3122 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3123 } 3124 3125 /* If this is the last chunk in a packet, we need to count it 3126 * toward sack generation. Note that we need to SACK every 3127 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3128 * THEM. We elect to NOT generate SACK's if the chunk fails 3129 * the verification tag test. 3130 * 3131 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3132 * 3133 * The SCTP endpoint MUST always acknowledge the reception of 3134 * each valid DATA chunk. 3135 * 3136 * The guidelines on delayed acknowledgement algorithm 3137 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3138 * Specifically, an acknowledgement SHOULD be generated for at 3139 * least every second packet (not every second DATA chunk) 3140 * received, and SHOULD be generated within 200 ms of the 3141 * arrival of any unacknowledged DATA chunk. In some 3142 * situations it may be beneficial for an SCTP transmitter to 3143 * be more conservative than the algorithms detailed in this 3144 * document allow. However, an SCTP transmitter MUST NOT be 3145 * more aggressive than the following algorithms allow. 3146 */ 3147 if (chunk->end_of_packet) 3148 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3149 3150 return SCTP_DISPOSITION_CONSUME; 3151 3152 discard_force: 3153 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3154 * 3155 * When a packet arrives with duplicate DATA chunk(s) and with 3156 * no new DATA chunk(s), the endpoint MUST immediately send a 3157 * SACK with no delay. If a packet arrives with duplicate 3158 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3159 * MAY immediately send a SACK. Normally receipt of duplicate 3160 * DATA chunks will occur when the original SACK chunk was lost 3161 * and the peer's RTO has expired. The duplicate TSN number(s) 3162 * SHOULD be reported in the SACK as duplicate. 3163 */ 3164 /* In our case, we split the MAY SACK advice up whether or not 3165 * the last chunk is a duplicate.' 3166 */ 3167 if (chunk->end_of_packet) 3168 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3169 return SCTP_DISPOSITION_DISCARD; 3170 3171 discard_noforce: 3172 if (chunk->end_of_packet) 3173 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3174 3175 return SCTP_DISPOSITION_DISCARD; 3176 } 3177 3178 /* 3179 * sctp_sf_eat_data_fast_4_4 3180 * 3181 * Section: 4 (4) 3182 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3183 * DATA chunks without delay. 3184 * 3185 * Verification Tag: 8.5 Verification Tag [Normal verification] 3186 * Inputs 3187 * (endpoint, asoc, chunk) 3188 * 3189 * Outputs 3190 * (asoc, reply_msg, msg_up, timers, counters) 3191 * 3192 * The return value is the disposition of the chunk. 3193 */ 3194 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3195 struct net *net, 3196 const struct sctp_endpoint *ep, 3197 const struct sctp_association *asoc, 3198 const union sctp_subtype type, 3199 void *arg, 3200 struct sctp_cmd_seq *commands) 3201 { 3202 struct sctp_chunk *chunk = arg; 3203 int error; 3204 3205 if (!sctp_vtag_verify(chunk, asoc)) { 3206 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3207 SCTP_NULL()); 3208 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3209 } 3210 3211 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3212 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3213 commands); 3214 3215 error = sctp_eat_data(asoc, chunk, commands); 3216 switch (error) { 3217 case SCTP_IERROR_NO_ERROR: 3218 case SCTP_IERROR_HIGH_TSN: 3219 case SCTP_IERROR_DUP_TSN: 3220 case SCTP_IERROR_IGNORE_TSN: 3221 case SCTP_IERROR_BAD_STREAM: 3222 break; 3223 case SCTP_IERROR_NO_DATA: 3224 return SCTP_DISPOSITION_ABORT; 3225 case SCTP_IERROR_PROTO_VIOLATION: 3226 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3227 (u8 *)chunk->subh.data_hdr, 3228 sctp_datahdr_len(&asoc->stream)); 3229 default: 3230 BUG(); 3231 } 3232 3233 /* Go a head and force a SACK, since we are shutting down. */ 3234 3235 /* Implementor's Guide. 3236 * 3237 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3238 * respond to each received packet containing one or more DATA chunk(s) 3239 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3240 */ 3241 if (chunk->end_of_packet) { 3242 /* We must delay the chunk creation since the cumulative 3243 * TSN has not been updated yet. 3244 */ 3245 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3246 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3247 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3248 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3249 } 3250 3251 return SCTP_DISPOSITION_CONSUME; 3252 } 3253 3254 /* 3255 * Section: 6.2 Processing a Received SACK 3256 * D) Any time a SACK arrives, the endpoint performs the following: 3257 * 3258 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3259 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3260 * increasing, a SACK whose Cumulative TSN Ack is less than the 3261 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3262 * 3263 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3264 * of bytes still outstanding after processing the Cumulative TSN Ack 3265 * and the Gap Ack Blocks. 3266 * 3267 * iii) If the SACK is missing a TSN that was previously 3268 * acknowledged via a Gap Ack Block (e.g., the data receiver 3269 * reneged on the data), then mark the corresponding DATA chunk 3270 * as available for retransmit: Mark it as missing for fast 3271 * retransmit as described in Section 7.2.4 and if no retransmit 3272 * timer is running for the destination address to which the DATA 3273 * chunk was originally transmitted, then T3-rtx is started for 3274 * that destination address. 3275 * 3276 * Verification Tag: 8.5 Verification Tag [Normal verification] 3277 * 3278 * Inputs 3279 * (endpoint, asoc, chunk) 3280 * 3281 * Outputs 3282 * (asoc, reply_msg, msg_up, timers, counters) 3283 * 3284 * The return value is the disposition of the chunk. 3285 */ 3286 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3287 const struct sctp_endpoint *ep, 3288 const struct sctp_association *asoc, 3289 const union sctp_subtype type, 3290 void *arg, 3291 struct sctp_cmd_seq *commands) 3292 { 3293 struct sctp_chunk *chunk = arg; 3294 struct sctp_sackhdr *sackh; 3295 __u32 ctsn; 3296 3297 trace_sctp_probe(ep, asoc, chunk); 3298 3299 if (!sctp_vtag_verify(chunk, asoc)) 3300 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3301 3302 /* Make sure that the SACK chunk has a valid length. */ 3303 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3304 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3305 commands); 3306 3307 /* Pull the SACK chunk from the data buffer */ 3308 sackh = sctp_sm_pull_sack(chunk); 3309 /* Was this a bogus SACK? */ 3310 if (!sackh) 3311 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3312 chunk->subh.sack_hdr = sackh; 3313 ctsn = ntohl(sackh->cum_tsn_ack); 3314 3315 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3316 * Ack Point, then drop the SACK. Since Cumulative TSN 3317 * Ack is monotonically increasing, a SACK whose 3318 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3319 * Point indicates an out-of-order SACK. 3320 */ 3321 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3322 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3323 asoc->ctsn_ack_point); 3324 3325 return SCTP_DISPOSITION_DISCARD; 3326 } 3327 3328 /* If Cumulative TSN Ack beyond the max tsn currently 3329 * send, terminating the association and respond to the 3330 * sender with an ABORT. 3331 */ 3332 if (!TSN_lt(ctsn, asoc->next_tsn)) 3333 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3334 3335 /* Return this SACK for further processing. */ 3336 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3337 3338 /* Note: We do the rest of the work on the PROCESS_SACK 3339 * sideeffect. 3340 */ 3341 return SCTP_DISPOSITION_CONSUME; 3342 } 3343 3344 /* 3345 * Generate an ABORT in response to a packet. 3346 * 3347 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3348 * 3349 * 8) The receiver should respond to the sender of the OOTB packet with 3350 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3351 * MUST fill in the Verification Tag field of the outbound packet 3352 * with the value found in the Verification Tag field of the OOTB 3353 * packet and set the T-bit in the Chunk Flags to indicate that the 3354 * Verification Tag is reflected. After sending this ABORT, the 3355 * receiver of the OOTB packet shall discard the OOTB packet and take 3356 * no further action. 3357 * 3358 * Verification Tag: 3359 * 3360 * The return value is the disposition of the chunk. 3361 */ 3362 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3363 struct net *net, 3364 const struct sctp_endpoint *ep, 3365 const struct sctp_association *asoc, 3366 const union sctp_subtype type, 3367 void *arg, 3368 struct sctp_cmd_seq *commands) 3369 { 3370 struct sctp_packet *packet = NULL; 3371 struct sctp_chunk *chunk = arg; 3372 struct sctp_chunk *abort; 3373 3374 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3375 if (!packet) 3376 return SCTP_DISPOSITION_NOMEM; 3377 3378 /* Make an ABORT. The T bit will be set if the asoc 3379 * is NULL. 3380 */ 3381 abort = sctp_make_abort(asoc, chunk, 0); 3382 if (!abort) { 3383 sctp_ootb_pkt_free(packet); 3384 return SCTP_DISPOSITION_NOMEM; 3385 } 3386 3387 /* Reflect vtag if T-Bit is set */ 3388 if (sctp_test_T_bit(abort)) 3389 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3390 3391 /* Set the skb to the belonging sock for accounting. */ 3392 abort->skb->sk = ep->base.sk; 3393 3394 sctp_packet_append_chunk(packet, abort); 3395 3396 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3397 SCTP_PACKET(packet)); 3398 3399 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3400 3401 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3402 return SCTP_DISPOSITION_CONSUME; 3403 } 3404 3405 /* 3406 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3407 * event as ULP notification for each cause included in the chunk. 3408 * 3409 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3410 * 3411 * The return value is the disposition of the chunk. 3412 */ 3413 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3414 const struct sctp_endpoint *ep, 3415 const struct sctp_association *asoc, 3416 const union sctp_subtype type, 3417 void *arg, 3418 struct sctp_cmd_seq *commands) 3419 { 3420 struct sctp_chunk *chunk = arg; 3421 struct sctp_errhdr *err; 3422 3423 if (!sctp_vtag_verify(chunk, asoc)) 3424 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3425 3426 /* Make sure that the ERROR chunk has a valid length. */ 3427 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3428 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3429 commands); 3430 sctp_walk_errors(err, chunk->chunk_hdr); 3431 if ((void *)err != (void *)chunk->chunk_end) 3432 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3433 (void *)err, commands); 3434 3435 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3436 SCTP_CHUNK(chunk)); 3437 3438 return SCTP_DISPOSITION_CONSUME; 3439 } 3440 3441 /* 3442 * Process an inbound SHUTDOWN ACK. 3443 * 3444 * From Section 9.2: 3445 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3446 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3447 * peer, and remove all record of the association. 3448 * 3449 * The return value is the disposition. 3450 */ 3451 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3452 const struct sctp_endpoint *ep, 3453 const struct sctp_association *asoc, 3454 const union sctp_subtype type, 3455 void *arg, 3456 struct sctp_cmd_seq *commands) 3457 { 3458 struct sctp_chunk *chunk = arg; 3459 struct sctp_chunk *reply; 3460 struct sctp_ulpevent *ev; 3461 3462 if (!sctp_vtag_verify(chunk, asoc)) 3463 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3464 3465 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3466 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3467 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3468 commands); 3469 /* 10.2 H) SHUTDOWN COMPLETE notification 3470 * 3471 * When SCTP completes the shutdown procedures (section 9.2) this 3472 * notification is passed to the upper layer. 3473 */ 3474 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3475 0, 0, 0, NULL, GFP_ATOMIC); 3476 if (!ev) 3477 goto nomem; 3478 3479 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3480 reply = sctp_make_shutdown_complete(asoc, chunk); 3481 if (!reply) 3482 goto nomem_chunk; 3483 3484 /* Do all the commands now (after allocation), so that we 3485 * have consistent state if memory allocation failes 3486 */ 3487 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3488 3489 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3490 * stop the T2-shutdown timer, 3491 */ 3492 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3493 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3494 3495 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3496 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3497 3498 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3499 SCTP_STATE(SCTP_STATE_CLOSED)); 3500 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3501 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3502 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3503 3504 /* ...and remove all record of the association. */ 3505 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3506 return SCTP_DISPOSITION_DELETE_TCB; 3507 3508 nomem_chunk: 3509 sctp_ulpevent_free(ev); 3510 nomem: 3511 return SCTP_DISPOSITION_NOMEM; 3512 } 3513 3514 /* 3515 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3516 * 3517 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3518 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3519 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3520 * packet must fill in the Verification Tag field of the outbound 3521 * packet with the Verification Tag received in the SHUTDOWN ACK and 3522 * set the T-bit in the Chunk Flags to indicate that the Verification 3523 * Tag is reflected. 3524 * 3525 * 8) The receiver should respond to the sender of the OOTB packet with 3526 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3527 * MUST fill in the Verification Tag field of the outbound packet 3528 * with the value found in the Verification Tag field of the OOTB 3529 * packet and set the T-bit in the Chunk Flags to indicate that the 3530 * Verification Tag is reflected. After sending this ABORT, the 3531 * receiver of the OOTB packet shall discard the OOTB packet and take 3532 * no further action. 3533 */ 3534 enum sctp_disposition sctp_sf_ootb(struct net *net, 3535 const struct sctp_endpoint *ep, 3536 const struct sctp_association *asoc, 3537 const union sctp_subtype type, 3538 void *arg, struct sctp_cmd_seq *commands) 3539 { 3540 struct sctp_chunk *chunk = arg; 3541 struct sk_buff *skb = chunk->skb; 3542 struct sctp_chunkhdr *ch; 3543 struct sctp_errhdr *err; 3544 int ootb_cookie_ack = 0; 3545 int ootb_shut_ack = 0; 3546 __u8 *ch_end; 3547 3548 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3549 3550 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3551 do { 3552 /* Report violation if the chunk is less then minimal */ 3553 if (ntohs(ch->length) < sizeof(*ch)) 3554 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3555 commands); 3556 3557 /* Report violation if chunk len overflows */ 3558 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3559 if (ch_end > skb_tail_pointer(skb)) 3560 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3561 commands); 3562 3563 /* Now that we know we at least have a chunk header, 3564 * do things that are type appropriate. 3565 */ 3566 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3567 ootb_shut_ack = 1; 3568 3569 /* RFC 2960, Section 3.3.7 3570 * Moreover, under any circumstances, an endpoint that 3571 * receives an ABORT MUST NOT respond to that ABORT by 3572 * sending an ABORT of its own. 3573 */ 3574 if (SCTP_CID_ABORT == ch->type) 3575 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3576 3577 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3578 * or a COOKIE ACK the SCTP Packet should be silently 3579 * discarded. 3580 */ 3581 3582 if (SCTP_CID_COOKIE_ACK == ch->type) 3583 ootb_cookie_ack = 1; 3584 3585 if (SCTP_CID_ERROR == ch->type) { 3586 sctp_walk_errors(err, ch) { 3587 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3588 ootb_cookie_ack = 1; 3589 break; 3590 } 3591 } 3592 } 3593 3594 ch = (struct sctp_chunkhdr *)ch_end; 3595 } while (ch_end < skb_tail_pointer(skb)); 3596 3597 if (ootb_shut_ack) 3598 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3599 else if (ootb_cookie_ack) 3600 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3601 else 3602 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3603 } 3604 3605 /* 3606 * Handle an "Out of the blue" SHUTDOWN ACK. 3607 * 3608 * Section: 8.4 5, sctpimpguide 2.41. 3609 * 3610 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3611 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3612 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3613 * packet must fill in the Verification Tag field of the outbound 3614 * packet with the Verification Tag received in the SHUTDOWN ACK and 3615 * set the T-bit in the Chunk Flags to indicate that the Verification 3616 * Tag is reflected. 3617 * 3618 * Inputs 3619 * (endpoint, asoc, type, arg, commands) 3620 * 3621 * Outputs 3622 * (enum sctp_disposition) 3623 * 3624 * The return value is the disposition of the chunk. 3625 */ 3626 static enum sctp_disposition sctp_sf_shut_8_4_5( 3627 struct net *net, 3628 const struct sctp_endpoint *ep, 3629 const struct sctp_association *asoc, 3630 const union sctp_subtype type, 3631 void *arg, 3632 struct sctp_cmd_seq *commands) 3633 { 3634 struct sctp_packet *packet = NULL; 3635 struct sctp_chunk *chunk = arg; 3636 struct sctp_chunk *shut; 3637 3638 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3639 if (!packet) 3640 return SCTP_DISPOSITION_NOMEM; 3641 3642 /* Make an SHUTDOWN_COMPLETE. 3643 * The T bit will be set if the asoc is NULL. 3644 */ 3645 shut = sctp_make_shutdown_complete(asoc, chunk); 3646 if (!shut) { 3647 sctp_ootb_pkt_free(packet); 3648 return SCTP_DISPOSITION_NOMEM; 3649 } 3650 3651 /* Reflect vtag if T-Bit is set */ 3652 if (sctp_test_T_bit(shut)) 3653 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3654 3655 /* Set the skb to the belonging sock for accounting. */ 3656 shut->skb->sk = ep->base.sk; 3657 3658 sctp_packet_append_chunk(packet, shut); 3659 3660 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3661 SCTP_PACKET(packet)); 3662 3663 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3664 3665 /* If the chunk length is invalid, we don't want to process 3666 * the reset of the packet. 3667 */ 3668 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3669 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3670 3671 /* We need to discard the rest of the packet to prevent 3672 * potential bomming attacks from additional bundled chunks. 3673 * This is documented in SCTP Threats ID. 3674 */ 3675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3676 } 3677 3678 /* 3679 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3680 * 3681 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3682 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3683 * procedures in section 8.4 SHOULD be followed, in other words it 3684 * should be treated as an Out Of The Blue packet. 3685 * [This means that we do NOT check the Verification Tag on these 3686 * chunks. --piggy ] 3687 * 3688 */ 3689 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3690 const struct sctp_endpoint *ep, 3691 const struct sctp_association *asoc, 3692 const union sctp_subtype type, 3693 void *arg, 3694 struct sctp_cmd_seq *commands) 3695 { 3696 struct sctp_chunk *chunk = arg; 3697 3698 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3699 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3700 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3701 commands); 3702 3703 /* Although we do have an association in this case, it corresponds 3704 * to a restarted association. So the packet is treated as an OOTB 3705 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3706 * called with a NULL association. 3707 */ 3708 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3709 3710 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3711 } 3712 3713 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3714 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3715 const struct sctp_endpoint *ep, 3716 const struct sctp_association *asoc, 3717 const union sctp_subtype type, 3718 void *arg, 3719 struct sctp_cmd_seq *commands) 3720 { 3721 struct sctp_paramhdr *err_param = NULL; 3722 struct sctp_chunk *asconf_ack = NULL; 3723 struct sctp_chunk *chunk = arg; 3724 struct sctp_addiphdr *hdr; 3725 __u32 serial; 3726 3727 if (!sctp_vtag_verify(chunk, asoc)) { 3728 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3729 SCTP_NULL()); 3730 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3731 } 3732 3733 /* ADD-IP: Section 4.1.1 3734 * This chunk MUST be sent in an authenticated way by using 3735 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3736 * is received unauthenticated it MUST be silently discarded as 3737 * described in [I-D.ietf-tsvwg-sctp-auth]. 3738 */ 3739 if (!net->sctp.addip_noauth && !chunk->auth) 3740 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3741 commands); 3742 3743 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3744 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3745 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3746 commands); 3747 3748 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3749 serial = ntohl(hdr->serial); 3750 3751 /* Verify the ASCONF chunk before processing it. */ 3752 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3753 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3754 (void *)err_param, commands); 3755 3756 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3757 * the endpoint stored in a new association variable 3758 * 'Peer-Serial-Number'. 3759 */ 3760 if (serial == asoc->peer.addip_serial + 1) { 3761 /* If this is the first instance of ASCONF in the packet, 3762 * we can clean our old ASCONF-ACKs. 3763 */ 3764 if (!chunk->has_asconf) 3765 sctp_assoc_clean_asconf_ack_cache(asoc); 3766 3767 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3768 * expected, process the ASCONF as described below and after 3769 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3770 * the response packet and cache a copy of it (in the event it 3771 * later needs to be retransmitted). 3772 * 3773 * Essentially, do V1-V5. 3774 */ 3775 asconf_ack = sctp_process_asconf((struct sctp_association *) 3776 asoc, chunk); 3777 if (!asconf_ack) 3778 return SCTP_DISPOSITION_NOMEM; 3779 } else if (serial < asoc->peer.addip_serial + 1) { 3780 /* ADDIP 5.2 E2) 3781 * If the value found in the Sequence Number is less than the 3782 * ('Peer- Sequence-Number' + 1), simply skip to the next 3783 * ASCONF, and include in the outbound response packet 3784 * any previously cached ASCONF-ACK response that was 3785 * sent and saved that matches the Sequence Number of the 3786 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3787 * Chunk exists. This will occur when an older ASCONF 3788 * arrives out of order. In such a case, the receiver 3789 * should skip the ASCONF Chunk and not include ASCONF-ACK 3790 * Chunk for that chunk. 3791 */ 3792 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3793 if (!asconf_ack) 3794 return SCTP_DISPOSITION_DISCARD; 3795 3796 /* Reset the transport so that we select the correct one 3797 * this time around. This is to make sure that we don't 3798 * accidentally use a stale transport that's been removed. 3799 */ 3800 asconf_ack->transport = NULL; 3801 } else { 3802 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3803 * it must be either a stale packet or from an attacker. 3804 */ 3805 return SCTP_DISPOSITION_DISCARD; 3806 } 3807 3808 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3809 * containing the ASCONF-ACK Chunks MUST be the source address of 3810 * the SCTP packet that held the ASCONF Chunks. 3811 * 3812 * To do this properly, we'll set the destination address of the chunk 3813 * and at the transmit time, will try look up the transport to use. 3814 * Since ASCONFs may be bundled, the correct transport may not be 3815 * created until we process the entire packet, thus this workaround. 3816 */ 3817 asconf_ack->dest = chunk->source; 3818 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3819 if (asoc->new_transport) { 3820 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3821 ((struct sctp_association *)asoc)->new_transport = NULL; 3822 } 3823 3824 return SCTP_DISPOSITION_CONSUME; 3825 } 3826 3827 static enum sctp_disposition sctp_send_next_asconf( 3828 struct net *net, 3829 const struct sctp_endpoint *ep, 3830 struct sctp_association *asoc, 3831 const union sctp_subtype type, 3832 struct sctp_cmd_seq *commands) 3833 { 3834 struct sctp_chunk *asconf; 3835 struct list_head *entry; 3836 3837 if (list_empty(&asoc->addip_chunk_list)) 3838 return SCTP_DISPOSITION_CONSUME; 3839 3840 entry = asoc->addip_chunk_list.next; 3841 asconf = list_entry(entry, struct sctp_chunk, list); 3842 3843 list_del_init(entry); 3844 sctp_chunk_hold(asconf); 3845 asoc->addip_last_asconf = asconf; 3846 3847 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 3848 } 3849 3850 /* 3851 * ADDIP Section 4.3 General rules for address manipulation 3852 * When building TLV parameters for the ASCONF Chunk that will add or 3853 * delete IP addresses the D0 to D13 rules should be applied: 3854 */ 3855 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 3856 const struct sctp_endpoint *ep, 3857 const struct sctp_association *asoc, 3858 const union sctp_subtype type, 3859 void *arg, 3860 struct sctp_cmd_seq *commands) 3861 { 3862 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3863 struct sctp_paramhdr *err_param = NULL; 3864 struct sctp_chunk *asconf_ack = arg; 3865 struct sctp_addiphdr *addip_hdr; 3866 __u32 sent_serial, rcvd_serial; 3867 struct sctp_chunk *abort; 3868 3869 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3870 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3871 SCTP_NULL()); 3872 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3873 } 3874 3875 /* ADD-IP, Section 4.1.2: 3876 * This chunk MUST be sent in an authenticated way by using 3877 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3878 * is received unauthenticated it MUST be silently discarded as 3879 * described in [I-D.ietf-tsvwg-sctp-auth]. 3880 */ 3881 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3882 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3883 commands); 3884 3885 /* Make sure that the ADDIP chunk has a valid length. */ 3886 if (!sctp_chunk_length_valid(asconf_ack, 3887 sizeof(struct sctp_addip_chunk))) 3888 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3889 commands); 3890 3891 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 3892 rcvd_serial = ntohl(addip_hdr->serial); 3893 3894 /* Verify the ASCONF-ACK chunk before processing it. */ 3895 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3896 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3897 (void *)err_param, commands); 3898 3899 if (last_asconf) { 3900 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr; 3901 sent_serial = ntohl(addip_hdr->serial); 3902 } else { 3903 sent_serial = asoc->addip_serial - 1; 3904 } 3905 3906 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3907 * equal to the next serial number to be used but no ASCONF chunk is 3908 * outstanding the endpoint MUST ABORT the association. Note that a 3909 * sequence number is greater than if it is no more than 2^^31-1 3910 * larger than the current sequence number (using serial arithmetic). 3911 */ 3912 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3913 !(asoc->addip_last_asconf)) { 3914 abort = sctp_make_abort(asoc, asconf_ack, 3915 sizeof(struct sctp_errhdr)); 3916 if (abort) { 3917 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3918 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3919 SCTP_CHUNK(abort)); 3920 } 3921 /* We are going to ABORT, so we might as well stop 3922 * processing the rest of the chunks in the packet. 3923 */ 3924 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3925 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3926 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3927 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3928 SCTP_ERROR(ECONNABORTED)); 3929 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3930 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3931 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3932 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3933 return SCTP_DISPOSITION_ABORT; 3934 } 3935 3936 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3937 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3938 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3939 3940 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3941 asconf_ack)) 3942 return sctp_send_next_asconf(net, ep, 3943 (struct sctp_association *)asoc, 3944 type, commands); 3945 3946 abort = sctp_make_abort(asoc, asconf_ack, 3947 sizeof(struct sctp_errhdr)); 3948 if (abort) { 3949 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3950 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3951 SCTP_CHUNK(abort)); 3952 } 3953 /* We are going to ABORT, so we might as well stop 3954 * processing the rest of the chunks in the packet. 3955 */ 3956 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3957 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3958 SCTP_ERROR(ECONNABORTED)); 3959 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3960 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3961 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3962 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3963 return SCTP_DISPOSITION_ABORT; 3964 } 3965 3966 return SCTP_DISPOSITION_DISCARD; 3967 } 3968 3969 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 3970 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 3971 const struct sctp_endpoint *ep, 3972 const struct sctp_association *asoc, 3973 const union sctp_subtype type, 3974 void *arg, 3975 struct sctp_cmd_seq *commands) 3976 { 3977 struct sctp_paramhdr *err_param = NULL; 3978 struct sctp_chunk *chunk = arg; 3979 struct sctp_reconf_chunk *hdr; 3980 union sctp_params param; 3981 3982 if (!sctp_vtag_verify(chunk, asoc)) { 3983 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3984 SCTP_NULL()); 3985 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3986 } 3987 3988 /* Make sure that the RECONF chunk has a valid length. */ 3989 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 3990 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3991 commands); 3992 3993 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 3994 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3995 (void *)err_param, commands); 3996 3997 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 3998 sctp_walk_params(param, hdr, params) { 3999 struct sctp_chunk *reply = NULL; 4000 struct sctp_ulpevent *ev = NULL; 4001 4002 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4003 reply = sctp_process_strreset_outreq( 4004 (struct sctp_association *)asoc, param, &ev); 4005 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4006 reply = sctp_process_strreset_inreq( 4007 (struct sctp_association *)asoc, param, &ev); 4008 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4009 reply = sctp_process_strreset_tsnreq( 4010 (struct sctp_association *)asoc, param, &ev); 4011 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4012 reply = sctp_process_strreset_addstrm_out( 4013 (struct sctp_association *)asoc, param, &ev); 4014 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4015 reply = sctp_process_strreset_addstrm_in( 4016 (struct sctp_association *)asoc, param, &ev); 4017 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4018 reply = sctp_process_strreset_resp( 4019 (struct sctp_association *)asoc, param, &ev); 4020 4021 if (ev) 4022 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4023 SCTP_ULPEVENT(ev)); 4024 4025 if (reply) 4026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4027 SCTP_CHUNK(reply)); 4028 } 4029 4030 return SCTP_DISPOSITION_CONSUME; 4031 } 4032 4033 /* 4034 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4035 * 4036 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4037 * its cumulative TSN point to the value carried in the FORWARD TSN 4038 * chunk, and then MUST further advance its cumulative TSN point locally 4039 * if possible. 4040 * After the above processing, the data receiver MUST stop reporting any 4041 * missing TSNs earlier than or equal to the new cumulative TSN point. 4042 * 4043 * Verification Tag: 8.5 Verification Tag [Normal verification] 4044 * 4045 * The return value is the disposition of the chunk. 4046 */ 4047 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4048 const struct sctp_endpoint *ep, 4049 const struct sctp_association *asoc, 4050 const union sctp_subtype type, 4051 void *arg, 4052 struct sctp_cmd_seq *commands) 4053 { 4054 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4055 struct sctp_chunk *chunk = arg; 4056 __u16 len; 4057 __u32 tsn; 4058 4059 if (!sctp_vtag_verify(chunk, asoc)) { 4060 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4061 SCTP_NULL()); 4062 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4063 } 4064 4065 if (!asoc->peer.prsctp_capable) 4066 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4067 4068 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4069 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4070 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4071 commands); 4072 4073 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4074 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4075 len = ntohs(chunk->chunk_hdr->length); 4076 len -= sizeof(struct sctp_chunkhdr); 4077 skb_pull(chunk->skb, len); 4078 4079 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4080 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4081 4082 /* The TSN is too high--silently discard the chunk and count on it 4083 * getting retransmitted later. 4084 */ 4085 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4086 goto discard_noforce; 4087 4088 if (!asoc->stream.si->validate_ftsn(chunk)) 4089 goto discard_noforce; 4090 4091 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4092 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4093 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4094 SCTP_CHUNK(chunk)); 4095 4096 /* Count this as receiving DATA. */ 4097 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4098 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4099 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4100 } 4101 4102 /* FIXME: For now send a SACK, but DATA processing may 4103 * send another. 4104 */ 4105 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4106 4107 return SCTP_DISPOSITION_CONSUME; 4108 4109 discard_noforce: 4110 return SCTP_DISPOSITION_DISCARD; 4111 } 4112 4113 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4114 struct net *net, 4115 const struct sctp_endpoint *ep, 4116 const struct sctp_association *asoc, 4117 const union sctp_subtype type, 4118 void *arg, 4119 struct sctp_cmd_seq *commands) 4120 { 4121 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4122 struct sctp_chunk *chunk = arg; 4123 __u16 len; 4124 __u32 tsn; 4125 4126 if (!sctp_vtag_verify(chunk, asoc)) { 4127 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4128 SCTP_NULL()); 4129 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4130 } 4131 4132 if (!asoc->peer.prsctp_capable) 4133 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4134 4135 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4136 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4137 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4138 commands); 4139 4140 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4141 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4142 len = ntohs(chunk->chunk_hdr->length); 4143 len -= sizeof(struct sctp_chunkhdr); 4144 skb_pull(chunk->skb, len); 4145 4146 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4147 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4148 4149 /* The TSN is too high--silently discard the chunk and count on it 4150 * getting retransmitted later. 4151 */ 4152 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4153 goto gen_shutdown; 4154 4155 if (!asoc->stream.si->validate_ftsn(chunk)) 4156 goto gen_shutdown; 4157 4158 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4159 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4160 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4161 SCTP_CHUNK(chunk)); 4162 4163 /* Go a head and force a SACK, since we are shutting down. */ 4164 gen_shutdown: 4165 /* Implementor's Guide. 4166 * 4167 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4168 * respond to each received packet containing one or more DATA chunk(s) 4169 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4170 */ 4171 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4172 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4173 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4174 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4175 4176 return SCTP_DISPOSITION_CONSUME; 4177 } 4178 4179 /* 4180 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 4181 * 4182 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4183 * Identifier field. If this algorithm was not specified by the 4184 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4185 * during association setup, the AUTH chunk and all chunks after it MUST 4186 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4187 * defined in Section 4.1. 4188 * 4189 * If an endpoint with no shared key receives a Shared Key Identifier 4190 * other than 0, it MUST silently discard all authenticated chunks. If 4191 * the endpoint has at least one endpoint pair shared key for the peer, 4192 * it MUST use the key specified by the Shared Key Identifier if a 4193 * key has been configured for that Shared Key Identifier. If no 4194 * endpoint pair shared key has been configured for that Shared Key 4195 * Identifier, all authenticated chunks MUST be silently discarded. 4196 * 4197 * Verification Tag: 8.5 Verification Tag [Normal verification] 4198 * 4199 * The return value is the disposition of the chunk. 4200 */ 4201 static enum sctp_ierror sctp_sf_authenticate( 4202 const struct sctp_association *asoc, 4203 struct sctp_chunk *chunk) 4204 { 4205 struct sctp_shared_key *sh_key = NULL; 4206 struct sctp_authhdr *auth_hdr; 4207 __u8 *save_digest, *digest; 4208 struct sctp_hmac *hmac; 4209 unsigned int sig_len; 4210 __u16 key_id; 4211 4212 /* Pull in the auth header, so we can do some more verification */ 4213 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4214 chunk->subh.auth_hdr = auth_hdr; 4215 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4216 4217 /* Make sure that we support the HMAC algorithm from the auth 4218 * chunk. 4219 */ 4220 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4221 return SCTP_IERROR_AUTH_BAD_HMAC; 4222 4223 /* Make sure that the provided shared key identifier has been 4224 * configured 4225 */ 4226 key_id = ntohs(auth_hdr->shkey_id); 4227 if (key_id != asoc->active_key_id) { 4228 sh_key = sctp_auth_get_shkey(asoc, key_id); 4229 if (!sh_key) 4230 return SCTP_IERROR_AUTH_BAD_KEYID; 4231 } 4232 4233 /* Make sure that the length of the signature matches what 4234 * we expect. 4235 */ 4236 sig_len = ntohs(chunk->chunk_hdr->length) - 4237 sizeof(struct sctp_auth_chunk); 4238 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4239 if (sig_len != hmac->hmac_len) 4240 return SCTP_IERROR_PROTO_VIOLATION; 4241 4242 /* Now that we've done validation checks, we can compute and 4243 * verify the hmac. The steps involved are: 4244 * 1. Save the digest from the chunk. 4245 * 2. Zero out the digest in the chunk. 4246 * 3. Compute the new digest 4247 * 4. Compare saved and new digests. 4248 */ 4249 digest = auth_hdr->hmac; 4250 skb_pull(chunk->skb, sig_len); 4251 4252 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4253 if (!save_digest) 4254 goto nomem; 4255 4256 memset(digest, 0, sig_len); 4257 4258 sctp_auth_calculate_hmac(asoc, chunk->skb, 4259 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4260 sh_key, GFP_ATOMIC); 4261 4262 /* Discard the packet if the digests do not match */ 4263 if (memcmp(save_digest, digest, sig_len)) { 4264 kfree(save_digest); 4265 return SCTP_IERROR_BAD_SIG; 4266 } 4267 4268 kfree(save_digest); 4269 chunk->auth = 1; 4270 4271 return SCTP_IERROR_NO_ERROR; 4272 nomem: 4273 return SCTP_IERROR_NOMEM; 4274 } 4275 4276 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4277 const struct sctp_endpoint *ep, 4278 const struct sctp_association *asoc, 4279 const union sctp_subtype type, 4280 void *arg, struct sctp_cmd_seq *commands) 4281 { 4282 struct sctp_chunk *chunk = arg; 4283 struct sctp_authhdr *auth_hdr; 4284 struct sctp_chunk *err_chunk; 4285 enum sctp_ierror error; 4286 4287 /* Make sure that the peer has AUTH capable */ 4288 if (!asoc->peer.auth_capable) 4289 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4290 4291 if (!sctp_vtag_verify(chunk, asoc)) { 4292 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4293 SCTP_NULL()); 4294 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4295 } 4296 4297 /* Make sure that the AUTH chunk has valid length. */ 4298 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4299 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4300 commands); 4301 4302 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4303 error = sctp_sf_authenticate(asoc, chunk); 4304 switch (error) { 4305 case SCTP_IERROR_AUTH_BAD_HMAC: 4306 /* Generate the ERROR chunk and discard the rest 4307 * of the packet 4308 */ 4309 err_chunk = sctp_make_op_error(asoc, chunk, 4310 SCTP_ERROR_UNSUP_HMAC, 4311 &auth_hdr->hmac_id, 4312 sizeof(__u16), 0); 4313 if (err_chunk) { 4314 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4315 SCTP_CHUNK(err_chunk)); 4316 } 4317 /* Fall Through */ 4318 case SCTP_IERROR_AUTH_BAD_KEYID: 4319 case SCTP_IERROR_BAD_SIG: 4320 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4321 4322 case SCTP_IERROR_PROTO_VIOLATION: 4323 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4324 commands); 4325 4326 case SCTP_IERROR_NOMEM: 4327 return SCTP_DISPOSITION_NOMEM; 4328 4329 default: /* Prevent gcc warnings */ 4330 break; 4331 } 4332 4333 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4334 struct sctp_ulpevent *ev; 4335 4336 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4337 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4338 4339 if (!ev) 4340 return -ENOMEM; 4341 4342 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4343 SCTP_ULPEVENT(ev)); 4344 } 4345 4346 return SCTP_DISPOSITION_CONSUME; 4347 } 4348 4349 /* 4350 * Process an unknown chunk. 4351 * 4352 * Section: 3.2. Also, 2.1 in the implementor's guide. 4353 * 4354 * Chunk Types are encoded such that the highest-order two bits specify 4355 * the action that must be taken if the processing endpoint does not 4356 * recognize the Chunk Type. 4357 * 4358 * 00 - Stop processing this SCTP packet and discard it, do not process 4359 * any further chunks within it. 4360 * 4361 * 01 - Stop processing this SCTP packet and discard it, do not process 4362 * any further chunks within it, and report the unrecognized 4363 * chunk in an 'Unrecognized Chunk Type'. 4364 * 4365 * 10 - Skip this chunk and continue processing. 4366 * 4367 * 11 - Skip this chunk and continue processing, but report in an ERROR 4368 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4369 * 4370 * The return value is the disposition of the chunk. 4371 */ 4372 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4373 const struct sctp_endpoint *ep, 4374 const struct sctp_association *asoc, 4375 const union sctp_subtype type, 4376 void *arg, 4377 struct sctp_cmd_seq *commands) 4378 { 4379 struct sctp_chunk *unk_chunk = arg; 4380 struct sctp_chunk *err_chunk; 4381 struct sctp_chunkhdr *hdr; 4382 4383 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4384 4385 if (!sctp_vtag_verify(unk_chunk, asoc)) 4386 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4387 4388 /* Make sure that the chunk has a valid length. 4389 * Since we don't know the chunk type, we use a general 4390 * chunkhdr structure to make a comparison. 4391 */ 4392 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4393 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4394 commands); 4395 4396 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4397 case SCTP_CID_ACTION_DISCARD: 4398 /* Discard the packet. */ 4399 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4400 case SCTP_CID_ACTION_DISCARD_ERR: 4401 /* Generate an ERROR chunk as response. */ 4402 hdr = unk_chunk->chunk_hdr; 4403 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4404 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4405 SCTP_PAD4(ntohs(hdr->length)), 4406 0); 4407 if (err_chunk) { 4408 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4409 SCTP_CHUNK(err_chunk)); 4410 } 4411 4412 /* Discard the packet. */ 4413 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4414 return SCTP_DISPOSITION_CONSUME; 4415 case SCTP_CID_ACTION_SKIP: 4416 /* Skip the chunk. */ 4417 return SCTP_DISPOSITION_DISCARD; 4418 case SCTP_CID_ACTION_SKIP_ERR: 4419 /* Generate an ERROR chunk as response. */ 4420 hdr = unk_chunk->chunk_hdr; 4421 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4422 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4423 SCTP_PAD4(ntohs(hdr->length)), 4424 0); 4425 if (err_chunk) { 4426 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4427 SCTP_CHUNK(err_chunk)); 4428 } 4429 /* Skip the chunk. */ 4430 return SCTP_DISPOSITION_CONSUME; 4431 default: 4432 break; 4433 } 4434 4435 return SCTP_DISPOSITION_DISCARD; 4436 } 4437 4438 /* 4439 * Discard the chunk. 4440 * 4441 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4442 * [Too numerous to mention...] 4443 * Verification Tag: No verification needed. 4444 * Inputs 4445 * (endpoint, asoc, chunk) 4446 * 4447 * Outputs 4448 * (asoc, reply_msg, msg_up, timers, counters) 4449 * 4450 * The return value is the disposition of the chunk. 4451 */ 4452 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4453 const struct sctp_endpoint *ep, 4454 const struct sctp_association *asoc, 4455 const union sctp_subtype type, 4456 void *arg, 4457 struct sctp_cmd_seq *commands) 4458 { 4459 struct sctp_chunk *chunk = arg; 4460 4461 /* Make sure that the chunk has a valid length. 4462 * Since we don't know the chunk type, we use a general 4463 * chunkhdr structure to make a comparison. 4464 */ 4465 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4466 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4467 commands); 4468 4469 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4470 4471 return SCTP_DISPOSITION_DISCARD; 4472 } 4473 4474 /* 4475 * Discard the whole packet. 4476 * 4477 * Section: 8.4 2) 4478 * 4479 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4480 * silently discard the OOTB packet and take no further action. 4481 * 4482 * Verification Tag: No verification necessary 4483 * 4484 * Inputs 4485 * (endpoint, asoc, chunk) 4486 * 4487 * Outputs 4488 * (asoc, reply_msg, msg_up, timers, counters) 4489 * 4490 * The return value is the disposition of the chunk. 4491 */ 4492 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4493 const struct sctp_endpoint *ep, 4494 const struct sctp_association *asoc, 4495 const union sctp_subtype type, 4496 void *arg, struct sctp_cmd_seq *commands) 4497 { 4498 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4499 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4500 4501 return SCTP_DISPOSITION_CONSUME; 4502 } 4503 4504 4505 /* 4506 * The other end is violating protocol. 4507 * 4508 * Section: Not specified 4509 * Verification Tag: Not specified 4510 * Inputs 4511 * (endpoint, asoc, chunk) 4512 * 4513 * Outputs 4514 * (asoc, reply_msg, msg_up, timers, counters) 4515 * 4516 * We simply tag the chunk as a violation. The state machine will log 4517 * the violation and continue. 4518 */ 4519 enum sctp_disposition sctp_sf_violation(struct net *net, 4520 const struct sctp_endpoint *ep, 4521 const struct sctp_association *asoc, 4522 const union sctp_subtype type, 4523 void *arg, 4524 struct sctp_cmd_seq *commands) 4525 { 4526 struct sctp_chunk *chunk = arg; 4527 4528 /* Make sure that the chunk has a valid length. */ 4529 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4530 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4531 commands); 4532 4533 return SCTP_DISPOSITION_VIOLATION; 4534 } 4535 4536 /* 4537 * Common function to handle a protocol violation. 4538 */ 4539 static enum sctp_disposition sctp_sf_abort_violation( 4540 struct net *net, 4541 const struct sctp_endpoint *ep, 4542 const struct sctp_association *asoc, 4543 void *arg, 4544 struct sctp_cmd_seq *commands, 4545 const __u8 *payload, 4546 const size_t paylen) 4547 { 4548 struct sctp_packet *packet = NULL; 4549 struct sctp_chunk *chunk = arg; 4550 struct sctp_chunk *abort = NULL; 4551 4552 /* SCTP-AUTH, Section 6.3: 4553 * It should be noted that if the receiver wants to tear 4554 * down an association in an authenticated way only, the 4555 * handling of malformed packets should not result in 4556 * tearing down the association. 4557 * 4558 * This means that if we only want to abort associations 4559 * in an authenticated way (i.e AUTH+ABORT), then we 4560 * can't destroy this association just because the packet 4561 * was malformed. 4562 */ 4563 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4564 goto discard; 4565 4566 /* Make the abort chunk. */ 4567 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4568 if (!abort) 4569 goto nomem; 4570 4571 if (asoc) { 4572 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4573 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4574 !asoc->peer.i.init_tag) { 4575 struct sctp_initack_chunk *initack; 4576 4577 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4578 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4579 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4580 else { 4581 unsigned int inittag; 4582 4583 inittag = ntohl(initack->init_hdr.init_tag); 4584 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4585 SCTP_U32(inittag)); 4586 } 4587 } 4588 4589 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4590 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4591 4592 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4595 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4596 SCTP_ERROR(ECONNREFUSED)); 4597 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4598 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4599 } else { 4600 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4601 SCTP_ERROR(ECONNABORTED)); 4602 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4603 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4604 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4605 } 4606 } else { 4607 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4608 4609 if (!packet) 4610 goto nomem_pkt; 4611 4612 if (sctp_test_T_bit(abort)) 4613 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4614 4615 abort->skb->sk = ep->base.sk; 4616 4617 sctp_packet_append_chunk(packet, abort); 4618 4619 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4620 SCTP_PACKET(packet)); 4621 4622 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4623 } 4624 4625 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4626 4627 discard: 4628 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4629 return SCTP_DISPOSITION_ABORT; 4630 4631 nomem_pkt: 4632 sctp_chunk_free(abort); 4633 nomem: 4634 return SCTP_DISPOSITION_NOMEM; 4635 } 4636 4637 /* 4638 * Handle a protocol violation when the chunk length is invalid. 4639 * "Invalid" length is identified as smaller than the minimal length a 4640 * given chunk can be. For example, a SACK chunk has invalid length 4641 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4642 * 4643 * We inform the other end by sending an ABORT with a Protocol Violation 4644 * error code. 4645 * 4646 * Section: Not specified 4647 * Verification Tag: Nothing to do 4648 * Inputs 4649 * (endpoint, asoc, chunk) 4650 * 4651 * Outputs 4652 * (reply_msg, msg_up, counters) 4653 * 4654 * Generate an ABORT chunk and terminate the association. 4655 */ 4656 static enum sctp_disposition sctp_sf_violation_chunklen( 4657 struct net *net, 4658 const struct sctp_endpoint *ep, 4659 const struct sctp_association *asoc, 4660 const union sctp_subtype type, 4661 void *arg, 4662 struct sctp_cmd_seq *commands) 4663 { 4664 static const char err_str[] = "The following chunk had invalid length:"; 4665 4666 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4667 sizeof(err_str)); 4668 } 4669 4670 /* 4671 * Handle a protocol violation when the parameter length is invalid. 4672 * If the length is smaller than the minimum length of a given parameter, 4673 * or accumulated length in multi parameters exceeds the end of the chunk, 4674 * the length is considered as invalid. 4675 */ 4676 static enum sctp_disposition sctp_sf_violation_paramlen( 4677 struct net *net, 4678 const struct sctp_endpoint *ep, 4679 const struct sctp_association *asoc, 4680 const union sctp_subtype type, 4681 void *arg, void *ext, 4682 struct sctp_cmd_seq *commands) 4683 { 4684 struct sctp_paramhdr *param = ext; 4685 struct sctp_chunk *abort = NULL; 4686 struct sctp_chunk *chunk = arg; 4687 4688 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4689 goto discard; 4690 4691 /* Make the abort chunk. */ 4692 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4693 if (!abort) 4694 goto nomem; 4695 4696 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4697 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4698 4699 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4700 SCTP_ERROR(ECONNABORTED)); 4701 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4702 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4703 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4704 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4705 4706 discard: 4707 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4708 return SCTP_DISPOSITION_ABORT; 4709 nomem: 4710 return SCTP_DISPOSITION_NOMEM; 4711 } 4712 4713 /* Handle a protocol violation when the peer trying to advance the 4714 * cumulative tsn ack to a point beyond the max tsn currently sent. 4715 * 4716 * We inform the other end by sending an ABORT with a Protocol Violation 4717 * error code. 4718 */ 4719 static enum sctp_disposition sctp_sf_violation_ctsn( 4720 struct net *net, 4721 const struct sctp_endpoint *ep, 4722 const struct sctp_association *asoc, 4723 const union sctp_subtype type, 4724 void *arg, 4725 struct sctp_cmd_seq *commands) 4726 { 4727 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4728 4729 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4730 sizeof(err_str)); 4731 } 4732 4733 /* Handle protocol violation of an invalid chunk bundling. For example, 4734 * when we have an association and we receive bundled INIT-ACK, or 4735 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4736 * statement from the specs. Additionally, there might be an attacker 4737 * on the path and we may not want to continue this communication. 4738 */ 4739 static enum sctp_disposition sctp_sf_violation_chunk( 4740 struct net *net, 4741 const struct sctp_endpoint *ep, 4742 const struct sctp_association *asoc, 4743 const union sctp_subtype type, 4744 void *arg, 4745 struct sctp_cmd_seq *commands) 4746 { 4747 static const char err_str[] = "The following chunk violates protocol:"; 4748 4749 if (!asoc) 4750 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4751 4752 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4753 sizeof(err_str)); 4754 } 4755 /*************************************************************************** 4756 * These are the state functions for handling primitive (Section 10) events. 4757 ***************************************************************************/ 4758 /* 4759 * sctp_sf_do_prm_asoc 4760 * 4761 * Section: 10.1 ULP-to-SCTP 4762 * B) Associate 4763 * 4764 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4765 * outbound stream count) 4766 * -> association id [,destination transport addr list] [,outbound stream 4767 * count] 4768 * 4769 * This primitive allows the upper layer to initiate an association to a 4770 * specific peer endpoint. 4771 * 4772 * The peer endpoint shall be specified by one of the transport addresses 4773 * which defines the endpoint (see Section 1.4). If the local SCTP 4774 * instance has not been initialized, the ASSOCIATE is considered an 4775 * error. 4776 * [This is not relevant for the kernel implementation since we do all 4777 * initialization at boot time. It we hadn't initialized we wouldn't 4778 * get anywhere near this code.] 4779 * 4780 * An association id, which is a local handle to the SCTP association, 4781 * will be returned on successful establishment of the association. If 4782 * SCTP is not able to open an SCTP association with the peer endpoint, 4783 * an error is returned. 4784 * [In the kernel implementation, the struct sctp_association needs to 4785 * be created BEFORE causing this primitive to run.] 4786 * 4787 * Other association parameters may be returned, including the 4788 * complete destination transport addresses of the peer as well as the 4789 * outbound stream count of the local endpoint. One of the transport 4790 * address from the returned destination addresses will be selected by 4791 * the local endpoint as default primary path for sending SCTP packets 4792 * to this peer. The returned "destination transport addr list" can 4793 * be used by the ULP to change the default primary path or to force 4794 * sending a packet to a specific transport address. [All of this 4795 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4796 * function.] 4797 * 4798 * Mandatory attributes: 4799 * 4800 * o local SCTP instance name - obtained from the INITIALIZE operation. 4801 * [This is the argument asoc.] 4802 * o destination transport addr - specified as one of the transport 4803 * addresses of the peer endpoint with which the association is to be 4804 * established. 4805 * [This is asoc->peer.active_path.] 4806 * o outbound stream count - the number of outbound streams the ULP 4807 * would like to open towards this peer endpoint. 4808 * [BUG: This is not currently implemented.] 4809 * Optional attributes: 4810 * 4811 * None. 4812 * 4813 * The return value is a disposition. 4814 */ 4815 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4816 const struct sctp_endpoint *ep, 4817 const struct sctp_association *asoc, 4818 const union sctp_subtype type, 4819 void *arg, 4820 struct sctp_cmd_seq *commands) 4821 { 4822 struct sctp_association *my_asoc; 4823 struct sctp_chunk *repl; 4824 4825 /* The comment below says that we enter COOKIE-WAIT AFTER 4826 * sending the INIT, but that doesn't actually work in our 4827 * implementation... 4828 */ 4829 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4830 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4831 4832 /* RFC 2960 5.1 Normal Establishment of an Association 4833 * 4834 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4835 * must provide its Verification Tag (Tag_A) in the Initiate 4836 * Tag field. Tag_A SHOULD be a random number in the range of 4837 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4838 */ 4839 4840 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4841 if (!repl) 4842 goto nomem; 4843 4844 /* Choose transport for INIT. */ 4845 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4846 SCTP_CHUNK(repl)); 4847 4848 /* Cast away the const modifier, as we want to just 4849 * rerun it through as a sideffect. 4850 */ 4851 my_asoc = (struct sctp_association *)asoc; 4852 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4853 4854 /* After sending the INIT, "A" starts the T1-init timer and 4855 * enters the COOKIE-WAIT state. 4856 */ 4857 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4858 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4859 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4860 return SCTP_DISPOSITION_CONSUME; 4861 4862 nomem: 4863 return SCTP_DISPOSITION_NOMEM; 4864 } 4865 4866 /* 4867 * Process the SEND primitive. 4868 * 4869 * Section: 10.1 ULP-to-SCTP 4870 * E) Send 4871 * 4872 * Format: SEND(association id, buffer address, byte count [,context] 4873 * [,stream id] [,life time] [,destination transport address] 4874 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4875 * -> result 4876 * 4877 * This is the main method to send user data via SCTP. 4878 * 4879 * Mandatory attributes: 4880 * 4881 * o association id - local handle to the SCTP association 4882 * 4883 * o buffer address - the location where the user message to be 4884 * transmitted is stored; 4885 * 4886 * o byte count - The size of the user data in number of bytes; 4887 * 4888 * Optional attributes: 4889 * 4890 * o context - an optional 32 bit integer that will be carried in the 4891 * sending failure notification to the ULP if the transportation of 4892 * this User Message fails. 4893 * 4894 * o stream id - to indicate which stream to send the data on. If not 4895 * specified, stream 0 will be used. 4896 * 4897 * o life time - specifies the life time of the user data. The user data 4898 * will not be sent by SCTP after the life time expires. This 4899 * parameter can be used to avoid efforts to transmit stale 4900 * user messages. SCTP notifies the ULP if the data cannot be 4901 * initiated to transport (i.e. sent to the destination via SCTP's 4902 * send primitive) within the life time variable. However, the 4903 * user data will be transmitted if SCTP has attempted to transmit a 4904 * chunk before the life time expired. 4905 * 4906 * o destination transport address - specified as one of the destination 4907 * transport addresses of the peer endpoint to which this packet 4908 * should be sent. Whenever possible, SCTP should use this destination 4909 * transport address for sending the packets, instead of the current 4910 * primary path. 4911 * 4912 * o unorder flag - this flag, if present, indicates that the user 4913 * would like the data delivered in an unordered fashion to the peer 4914 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4915 * message). 4916 * 4917 * o no-bundle flag - instructs SCTP not to bundle this user data with 4918 * other outbound DATA chunks. SCTP MAY still bundle even when 4919 * this flag is present, when faced with network congestion. 4920 * 4921 * o payload protocol-id - A 32 bit unsigned integer that is to be 4922 * passed to the peer indicating the type of payload protocol data 4923 * being transmitted. This value is passed as opaque data by SCTP. 4924 * 4925 * The return value is the disposition. 4926 */ 4927 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 4928 const struct sctp_endpoint *ep, 4929 const struct sctp_association *asoc, 4930 const union sctp_subtype type, 4931 void *arg, 4932 struct sctp_cmd_seq *commands) 4933 { 4934 struct sctp_datamsg *msg = arg; 4935 4936 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4937 return SCTP_DISPOSITION_CONSUME; 4938 } 4939 4940 /* 4941 * Process the SHUTDOWN primitive. 4942 * 4943 * Section: 10.1: 4944 * C) Shutdown 4945 * 4946 * Format: SHUTDOWN(association id) 4947 * -> result 4948 * 4949 * Gracefully closes an association. Any locally queued user data 4950 * will be delivered to the peer. The association will be terminated only 4951 * after the peer acknowledges all the SCTP packets sent. A success code 4952 * will be returned on successful termination of the association. If 4953 * attempting to terminate the association results in a failure, an error 4954 * code shall be returned. 4955 * 4956 * Mandatory attributes: 4957 * 4958 * o association id - local handle to the SCTP association 4959 * 4960 * Optional attributes: 4961 * 4962 * None. 4963 * 4964 * The return value is the disposition. 4965 */ 4966 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 4967 struct net *net, 4968 const struct sctp_endpoint *ep, 4969 const struct sctp_association *asoc, 4970 const union sctp_subtype type, 4971 void *arg, 4972 struct sctp_cmd_seq *commands) 4973 { 4974 enum sctp_disposition disposition; 4975 4976 /* From 9.2 Shutdown of an Association 4977 * Upon receipt of the SHUTDOWN primitive from its upper 4978 * layer, the endpoint enters SHUTDOWN-PENDING state and 4979 * remains there until all outstanding data has been 4980 * acknowledged by its peer. The endpoint accepts no new data 4981 * from its upper layer, but retransmits data to the far end 4982 * if necessary to fill gaps. 4983 */ 4984 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4985 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4986 4987 disposition = SCTP_DISPOSITION_CONSUME; 4988 if (sctp_outq_is_empty(&asoc->outqueue)) { 4989 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4990 arg, commands); 4991 } 4992 4993 return disposition; 4994 } 4995 4996 /* 4997 * Process the ABORT primitive. 4998 * 4999 * Section: 10.1: 5000 * C) Abort 5001 * 5002 * Format: Abort(association id [, cause code]) 5003 * -> result 5004 * 5005 * Ungracefully closes an association. Any locally queued user data 5006 * will be discarded and an ABORT chunk is sent to the peer. A success code 5007 * will be returned on successful abortion of the association. If 5008 * attempting to abort the association results in a failure, an error 5009 * code shall be returned. 5010 * 5011 * Mandatory attributes: 5012 * 5013 * o association id - local handle to the SCTP association 5014 * 5015 * Optional attributes: 5016 * 5017 * o cause code - reason of the abort to be passed to the peer 5018 * 5019 * None. 5020 * 5021 * The return value is the disposition. 5022 */ 5023 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5024 struct net *net, 5025 const struct sctp_endpoint *ep, 5026 const struct sctp_association *asoc, 5027 const union sctp_subtype type, 5028 void *arg, 5029 struct sctp_cmd_seq *commands) 5030 { 5031 /* From 9.1 Abort of an Association 5032 * Upon receipt of the ABORT primitive from its upper 5033 * layer, the endpoint enters CLOSED state and 5034 * discard all outstanding data has been 5035 * acknowledged by its peer. The endpoint accepts no new data 5036 * from its upper layer, but retransmits data to the far end 5037 * if necessary to fill gaps. 5038 */ 5039 struct sctp_chunk *abort = arg; 5040 5041 if (abort) 5042 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5043 5044 /* Even if we can't send the ABORT due to low memory delete the 5045 * TCB. This is a departure from our typical NOMEM handling. 5046 */ 5047 5048 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5049 SCTP_ERROR(ECONNABORTED)); 5050 /* Delete the established association. */ 5051 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5052 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5053 5054 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5055 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5056 5057 return SCTP_DISPOSITION_ABORT; 5058 } 5059 5060 /* We tried an illegal operation on an association which is closed. */ 5061 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5062 const struct sctp_endpoint *ep, 5063 const struct sctp_association *asoc, 5064 const union sctp_subtype type, 5065 void *arg, 5066 struct sctp_cmd_seq *commands) 5067 { 5068 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5069 return SCTP_DISPOSITION_CONSUME; 5070 } 5071 5072 /* We tried an illegal operation on an association which is shutting 5073 * down. 5074 */ 5075 enum sctp_disposition sctp_sf_error_shutdown( 5076 struct net *net, 5077 const struct sctp_endpoint *ep, 5078 const struct sctp_association *asoc, 5079 const union sctp_subtype type, 5080 void *arg, 5081 struct sctp_cmd_seq *commands) 5082 { 5083 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5084 SCTP_ERROR(-ESHUTDOWN)); 5085 return SCTP_DISPOSITION_CONSUME; 5086 } 5087 5088 /* 5089 * sctp_cookie_wait_prm_shutdown 5090 * 5091 * Section: 4 Note: 2 5092 * Verification Tag: 5093 * Inputs 5094 * (endpoint, asoc) 5095 * 5096 * The RFC does not explicitly address this issue, but is the route through the 5097 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5098 * 5099 * Outputs 5100 * (timers) 5101 */ 5102 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5103 struct net *net, 5104 const struct sctp_endpoint *ep, 5105 const struct sctp_association *asoc, 5106 const union sctp_subtype type, 5107 void *arg, 5108 struct sctp_cmd_seq *commands) 5109 { 5110 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5111 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5112 5113 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5114 SCTP_STATE(SCTP_STATE_CLOSED)); 5115 5116 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5117 5118 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5119 5120 return SCTP_DISPOSITION_DELETE_TCB; 5121 } 5122 5123 /* 5124 * sctp_cookie_echoed_prm_shutdown 5125 * 5126 * Section: 4 Note: 2 5127 * Verification Tag: 5128 * Inputs 5129 * (endpoint, asoc) 5130 * 5131 * The RFC does not explcitly address this issue, but is the route through the 5132 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5133 * 5134 * Outputs 5135 * (timers) 5136 */ 5137 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5138 struct net *net, 5139 const struct sctp_endpoint *ep, 5140 const struct sctp_association *asoc, 5141 const union sctp_subtype type, 5142 void *arg, 5143 struct sctp_cmd_seq *commands) 5144 { 5145 /* There is a single T1 timer, so we should be able to use 5146 * common function with the COOKIE-WAIT state. 5147 */ 5148 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5149 } 5150 5151 /* 5152 * sctp_sf_cookie_wait_prm_abort 5153 * 5154 * Section: 4 Note: 2 5155 * Verification Tag: 5156 * Inputs 5157 * (endpoint, asoc) 5158 * 5159 * The RFC does not explicitly address this issue, but is the route through the 5160 * state table when someone issues an abort while in COOKIE_WAIT state. 5161 * 5162 * Outputs 5163 * (timers) 5164 */ 5165 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5166 struct net *net, 5167 const struct sctp_endpoint *ep, 5168 const struct sctp_association *asoc, 5169 const union sctp_subtype type, 5170 void *arg, 5171 struct sctp_cmd_seq *commands) 5172 { 5173 struct sctp_chunk *abort = arg; 5174 5175 /* Stop T1-init timer */ 5176 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5177 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5178 5179 if (abort) 5180 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5181 5182 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5183 SCTP_STATE(SCTP_STATE_CLOSED)); 5184 5185 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5186 5187 /* Even if we can't send the ABORT due to low memory delete the 5188 * TCB. This is a departure from our typical NOMEM handling. 5189 */ 5190 5191 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5192 SCTP_ERROR(ECONNREFUSED)); 5193 /* Delete the established association. */ 5194 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5195 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5196 5197 return SCTP_DISPOSITION_ABORT; 5198 } 5199 5200 /* 5201 * sctp_sf_cookie_echoed_prm_abort 5202 * 5203 * Section: 4 Note: 3 5204 * Verification Tag: 5205 * Inputs 5206 * (endpoint, asoc) 5207 * 5208 * The RFC does not explcitly address this issue, but is the route through the 5209 * state table when someone issues an abort while in COOKIE_ECHOED state. 5210 * 5211 * Outputs 5212 * (timers) 5213 */ 5214 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5215 struct net *net, 5216 const struct sctp_endpoint *ep, 5217 const struct sctp_association *asoc, 5218 const union sctp_subtype type, 5219 void *arg, 5220 struct sctp_cmd_seq *commands) 5221 { 5222 /* There is a single T1 timer, so we should be able to use 5223 * common function with the COOKIE-WAIT state. 5224 */ 5225 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5226 } 5227 5228 /* 5229 * sctp_sf_shutdown_pending_prm_abort 5230 * 5231 * Inputs 5232 * (endpoint, asoc) 5233 * 5234 * The RFC does not explicitly address this issue, but is the route through the 5235 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5236 * 5237 * Outputs 5238 * (timers) 5239 */ 5240 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5241 struct net *net, 5242 const struct sctp_endpoint *ep, 5243 const struct sctp_association *asoc, 5244 const union sctp_subtype type, 5245 void *arg, 5246 struct sctp_cmd_seq *commands) 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_shutdown_sent_prm_abort 5257 * 5258 * Inputs 5259 * (endpoint, asoc) 5260 * 5261 * The RFC does not explicitly address this issue, but is the route through the 5262 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5263 * 5264 * Outputs 5265 * (timers) 5266 */ 5267 enum sctp_disposition sctp_sf_shutdown_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 /* Stop the T2-shutdown timer. */ 5276 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5277 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5278 5279 /* Stop the T5-shutdown guard timer. */ 5280 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5281 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5282 5283 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5284 } 5285 5286 /* 5287 * sctp_sf_cookie_echoed_prm_abort 5288 * 5289 * Inputs 5290 * (endpoint, asoc) 5291 * 5292 * The RFC does not explcitly address this issue, but is the route through the 5293 * state table when someone issues an abort while in COOKIE_ECHOED state. 5294 * 5295 * Outputs 5296 * (timers) 5297 */ 5298 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5299 struct net *net, 5300 const struct sctp_endpoint *ep, 5301 const struct sctp_association *asoc, 5302 const union sctp_subtype type, 5303 void *arg, 5304 struct sctp_cmd_seq *commands) 5305 { 5306 /* The same T2 timer, so we should be able to use 5307 * common function with the SHUTDOWN-SENT state. 5308 */ 5309 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5310 } 5311 5312 /* 5313 * Process the REQUESTHEARTBEAT primitive 5314 * 5315 * 10.1 ULP-to-SCTP 5316 * J) Request Heartbeat 5317 * 5318 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5319 * 5320 * -> result 5321 * 5322 * Instructs the local endpoint to perform a HeartBeat on the specified 5323 * destination transport address of the given association. The returned 5324 * result should indicate whether the transmission of the HEARTBEAT 5325 * chunk to the destination address is successful. 5326 * 5327 * Mandatory attributes: 5328 * 5329 * o association id - local handle to the SCTP association 5330 * 5331 * o destination transport address - the transport address of the 5332 * association on which a heartbeat should be issued. 5333 */ 5334 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5335 struct net *net, 5336 const struct sctp_endpoint *ep, 5337 const struct sctp_association *asoc, 5338 const union sctp_subtype type, 5339 void *arg, 5340 struct sctp_cmd_seq *commands) 5341 { 5342 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5343 (struct sctp_transport *)arg, commands)) 5344 return SCTP_DISPOSITION_NOMEM; 5345 5346 /* 5347 * RFC 2960 (bis), section 8.3 5348 * 5349 * D) Request an on-demand HEARTBEAT on a specific destination 5350 * transport address of a given association. 5351 * 5352 * The endpoint should increment the respective error counter of 5353 * the destination transport address each time a HEARTBEAT is sent 5354 * to that address and not acknowledged within one RTO. 5355 * 5356 */ 5357 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5358 SCTP_TRANSPORT(arg)); 5359 return SCTP_DISPOSITION_CONSUME; 5360 } 5361 5362 /* 5363 * ADDIP Section 4.1 ASCONF Chunk Procedures 5364 * When an endpoint has an ASCONF signaled change to be sent to the 5365 * remote endpoint it should do A1 to A9 5366 */ 5367 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5368 const struct sctp_endpoint *ep, 5369 const struct sctp_association *asoc, 5370 const union sctp_subtype type, 5371 void *arg, 5372 struct sctp_cmd_seq *commands) 5373 { 5374 struct sctp_chunk *chunk = arg; 5375 5376 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5377 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5378 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5379 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5380 return SCTP_DISPOSITION_CONSUME; 5381 } 5382 5383 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5384 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5385 const struct sctp_endpoint *ep, 5386 const struct sctp_association *asoc, 5387 const union sctp_subtype type, 5388 void *arg, 5389 struct sctp_cmd_seq *commands) 5390 { 5391 struct sctp_chunk *chunk = arg; 5392 5393 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5394 return SCTP_DISPOSITION_CONSUME; 5395 } 5396 5397 /* 5398 * Ignore the primitive event 5399 * 5400 * The return value is the disposition of the primitive. 5401 */ 5402 enum sctp_disposition sctp_sf_ignore_primitive( 5403 struct net *net, 5404 const struct sctp_endpoint *ep, 5405 const struct sctp_association *asoc, 5406 const union sctp_subtype type, 5407 void *arg, 5408 struct sctp_cmd_seq *commands) 5409 { 5410 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5411 type.primitive); 5412 5413 return SCTP_DISPOSITION_DISCARD; 5414 } 5415 5416 /*************************************************************************** 5417 * These are the state functions for the OTHER events. 5418 ***************************************************************************/ 5419 5420 /* 5421 * When the SCTP stack has no more user data to send or retransmit, this 5422 * notification is given to the user. Also, at the time when a user app 5423 * subscribes to this event, if there is no data to be sent or 5424 * retransmit, the stack will immediately send up this notification. 5425 */ 5426 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5427 struct net *net, 5428 const struct sctp_endpoint *ep, 5429 const struct sctp_association *asoc, 5430 const union sctp_subtype type, 5431 void *arg, 5432 struct sctp_cmd_seq *commands) 5433 { 5434 struct sctp_ulpevent *event; 5435 5436 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5437 if (!event) 5438 return SCTP_DISPOSITION_NOMEM; 5439 5440 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5441 5442 return SCTP_DISPOSITION_CONSUME; 5443 } 5444 5445 /* 5446 * Start the shutdown negotiation. 5447 * 5448 * From Section 9.2: 5449 * Once all its outstanding data has been acknowledged, the endpoint 5450 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5451 * TSN Ack field the last sequential TSN it has received from the peer. 5452 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5453 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5454 * with the updated last sequential TSN received from its peer. 5455 * 5456 * The return value is the disposition. 5457 */ 5458 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5459 struct net *net, 5460 const struct sctp_endpoint *ep, 5461 const struct sctp_association *asoc, 5462 const union sctp_subtype type, 5463 void *arg, 5464 struct sctp_cmd_seq *commands) 5465 { 5466 struct sctp_chunk *reply; 5467 5468 /* Once all its outstanding data has been acknowledged, the 5469 * endpoint shall send a SHUTDOWN chunk to its peer including 5470 * in the Cumulative TSN Ack field the last sequential TSN it 5471 * has received from the peer. 5472 */ 5473 reply = sctp_make_shutdown(asoc, NULL); 5474 if (!reply) 5475 goto nomem; 5476 5477 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5478 * T2-shutdown timer. 5479 */ 5480 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5481 5482 /* It shall then start the T2-shutdown timer */ 5483 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5484 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5485 5486 /* RFC 4960 Section 9.2 5487 * The sender of the SHUTDOWN MAY also start an overall guard timer 5488 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5489 */ 5490 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5491 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5492 5493 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5494 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5495 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5496 5497 /* and enter the SHUTDOWN-SENT state. */ 5498 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5499 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5500 5501 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5502 * 5503 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5504 * or SHUTDOWN-ACK. 5505 */ 5506 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5507 5508 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5509 5510 return SCTP_DISPOSITION_CONSUME; 5511 5512 nomem: 5513 return SCTP_DISPOSITION_NOMEM; 5514 } 5515 5516 /* 5517 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5518 * 5519 * From Section 9.2: 5520 * 5521 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5522 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5523 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5524 * endpoint must re-send the SHUTDOWN ACK. 5525 * 5526 * The return value is the disposition. 5527 */ 5528 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5529 struct net *net, 5530 const struct sctp_endpoint *ep, 5531 const struct sctp_association *asoc, 5532 const union sctp_subtype type, 5533 void *arg, 5534 struct sctp_cmd_seq *commands) 5535 { 5536 struct sctp_chunk *chunk = arg; 5537 struct sctp_chunk *reply; 5538 5539 /* There are 2 ways of getting here: 5540 * 1) called in response to a SHUTDOWN chunk 5541 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5542 * 5543 * For the case (2), the arg parameter is set to NULL. We need 5544 * to check that we have a chunk before accessing it's fields. 5545 */ 5546 if (chunk) { 5547 if (!sctp_vtag_verify(chunk, asoc)) 5548 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5549 commands); 5550 5551 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5552 if (!sctp_chunk_length_valid( 5553 chunk, sizeof(struct sctp_shutdown_chunk))) 5554 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5555 arg, commands); 5556 } 5557 5558 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5559 * shall send a SHUTDOWN ACK ... 5560 */ 5561 reply = sctp_make_shutdown_ack(asoc, chunk); 5562 if (!reply) 5563 goto nomem; 5564 5565 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5566 * the T2-shutdown timer. 5567 */ 5568 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5569 5570 /* and start/restart a T2-shutdown timer of its own, */ 5571 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5572 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5573 5574 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5575 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5576 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5577 5578 /* Enter the SHUTDOWN-ACK-SENT state. */ 5579 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5580 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5581 5582 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5583 * 5584 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5585 * or SHUTDOWN-ACK. 5586 */ 5587 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5588 5589 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5590 5591 return SCTP_DISPOSITION_CONSUME; 5592 5593 nomem: 5594 return SCTP_DISPOSITION_NOMEM; 5595 } 5596 5597 /* 5598 * Ignore the event defined as other 5599 * 5600 * The return value is the disposition of the event. 5601 */ 5602 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5603 const struct sctp_endpoint *ep, 5604 const struct sctp_association *asoc, 5605 const union sctp_subtype type, 5606 void *arg, 5607 struct sctp_cmd_seq *commands) 5608 { 5609 pr_debug("%s: the event other type:%d is ignored\n", 5610 __func__, type.other); 5611 5612 return SCTP_DISPOSITION_DISCARD; 5613 } 5614 5615 /************************************************************ 5616 * These are the state functions for handling timeout events. 5617 ************************************************************/ 5618 5619 /* 5620 * RTX Timeout 5621 * 5622 * Section: 6.3.3 Handle T3-rtx Expiration 5623 * 5624 * Whenever the retransmission timer T3-rtx expires for a destination 5625 * address, do the following: 5626 * [See below] 5627 * 5628 * The return value is the disposition of the chunk. 5629 */ 5630 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5631 const struct sctp_endpoint *ep, 5632 const struct sctp_association *asoc, 5633 const union sctp_subtype type, 5634 void *arg, 5635 struct sctp_cmd_seq *commands) 5636 { 5637 struct sctp_transport *transport = arg; 5638 5639 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5640 5641 if (asoc->overall_error_count >= asoc->max_retrans) { 5642 if (asoc->peer.zero_window_announced && 5643 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5644 /* 5645 * We are here likely because the receiver had its rwnd 5646 * closed for a while and we have not been able to 5647 * transmit the locally queued data within the maximum 5648 * retransmission attempts limit. Start the T5 5649 * shutdown guard timer to give the receiver one last 5650 * chance and some additional time to recover before 5651 * aborting. 5652 */ 5653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5654 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5655 } else { 5656 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5657 SCTP_ERROR(ETIMEDOUT)); 5658 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5659 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5660 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5661 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5662 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5663 return SCTP_DISPOSITION_DELETE_TCB; 5664 } 5665 } 5666 5667 /* E1) For the destination address for which the timer 5668 * expires, adjust its ssthresh with rules defined in Section 5669 * 7.2.3 and set the cwnd <- MTU. 5670 */ 5671 5672 /* E2) For the destination address for which the timer 5673 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5674 * maximum value discussed in rule C7 above (RTO.max) may be 5675 * used to provide an upper bound to this doubling operation. 5676 */ 5677 5678 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5679 * outstanding DATA chunks for the address for which the 5680 * T3-rtx has expired will fit into a single packet, subject 5681 * to the MTU constraint for the path corresponding to the 5682 * destination transport address to which the retransmission 5683 * is being sent (this may be different from the address for 5684 * which the timer expires [see Section 6.4]). Call this 5685 * value K. Bundle and retransmit those K DATA chunks in a 5686 * single packet to the destination endpoint. 5687 * 5688 * Note: Any DATA chunks that were sent to the address for 5689 * which the T3-rtx timer expired but did not fit in one MTU 5690 * (rule E3 above), should be marked for retransmission and 5691 * sent as soon as cwnd allows (normally when a SACK arrives). 5692 */ 5693 5694 /* Do some failure management (Section 8.2). */ 5695 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5696 5697 /* NB: Rules E4 and F1 are implicit in R1. */ 5698 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5699 5700 return SCTP_DISPOSITION_CONSUME; 5701 } 5702 5703 /* 5704 * Generate delayed SACK on timeout 5705 * 5706 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5707 * 5708 * The guidelines on delayed acknowledgement algorithm specified in 5709 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5710 * acknowledgement SHOULD be generated for at least every second packet 5711 * (not every second DATA chunk) received, and SHOULD be generated 5712 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5713 * some situations it may be beneficial for an SCTP transmitter to be 5714 * more conservative than the algorithms detailed in this document 5715 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5716 * the following algorithms allow. 5717 */ 5718 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5719 const struct sctp_endpoint *ep, 5720 const struct sctp_association *asoc, 5721 const union sctp_subtype type, 5722 void *arg, 5723 struct sctp_cmd_seq *commands) 5724 { 5725 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5726 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5727 return SCTP_DISPOSITION_CONSUME; 5728 } 5729 5730 /* 5731 * sctp_sf_t1_init_timer_expire 5732 * 5733 * Section: 4 Note: 2 5734 * Verification Tag: 5735 * Inputs 5736 * (endpoint, asoc) 5737 * 5738 * RFC 2960 Section 4 Notes 5739 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5740 * and re-start the T1-init timer without changing state. This MUST 5741 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5742 * endpoint MUST abort the initialization process and report the 5743 * error to SCTP user. 5744 * 5745 * Outputs 5746 * (timers, events) 5747 * 5748 */ 5749 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5750 struct net *net, 5751 const struct sctp_endpoint *ep, 5752 const struct sctp_association *asoc, 5753 const union sctp_subtype type, 5754 void *arg, 5755 struct sctp_cmd_seq *commands) 5756 { 5757 int attempts = asoc->init_err_counter + 1; 5758 struct sctp_chunk *repl = NULL; 5759 struct sctp_bind_addr *bp; 5760 5761 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5762 5763 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5764 5765 if (attempts <= asoc->max_init_attempts) { 5766 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5767 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5768 if (!repl) 5769 return SCTP_DISPOSITION_NOMEM; 5770 5771 /* Choose transport for INIT. */ 5772 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5773 SCTP_CHUNK(repl)); 5774 5775 /* Issue a sideeffect to do the needed accounting. */ 5776 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5777 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5778 5779 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5780 } else { 5781 pr_debug("%s: giving up on INIT, attempts:%d " 5782 "max_init_attempts:%d\n", __func__, attempts, 5783 asoc->max_init_attempts); 5784 5785 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5786 SCTP_ERROR(ETIMEDOUT)); 5787 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5788 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5789 return SCTP_DISPOSITION_DELETE_TCB; 5790 } 5791 5792 return SCTP_DISPOSITION_CONSUME; 5793 } 5794 5795 /* 5796 * sctp_sf_t1_cookie_timer_expire 5797 * 5798 * Section: 4 Note: 2 5799 * Verification Tag: 5800 * Inputs 5801 * (endpoint, asoc) 5802 * 5803 * RFC 2960 Section 4 Notes 5804 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5805 * COOKIE ECHO and re-start the T1-cookie timer without changing 5806 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5807 * After that, the endpoint MUST abort the initialization process and 5808 * report the error to SCTP user. 5809 * 5810 * Outputs 5811 * (timers, events) 5812 * 5813 */ 5814 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5815 struct net *net, 5816 const struct sctp_endpoint *ep, 5817 const struct sctp_association *asoc, 5818 const union sctp_subtype type, 5819 void *arg, 5820 struct sctp_cmd_seq *commands) 5821 { 5822 int attempts = asoc->init_err_counter + 1; 5823 struct sctp_chunk *repl = NULL; 5824 5825 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5826 5827 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5828 5829 if (attempts <= asoc->max_init_attempts) { 5830 repl = sctp_make_cookie_echo(asoc, NULL); 5831 if (!repl) 5832 return SCTP_DISPOSITION_NOMEM; 5833 5834 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5835 SCTP_CHUNK(repl)); 5836 /* Issue a sideeffect to do the needed accounting. */ 5837 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5838 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5839 5840 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5841 } else { 5842 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5843 SCTP_ERROR(ETIMEDOUT)); 5844 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5845 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5846 return SCTP_DISPOSITION_DELETE_TCB; 5847 } 5848 5849 return SCTP_DISPOSITION_CONSUME; 5850 } 5851 5852 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5853 * with the updated last sequential TSN received from its peer. 5854 * 5855 * An endpoint should limit the number of retransmissions of the 5856 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5857 * If this threshold is exceeded the endpoint should destroy the TCB and 5858 * MUST report the peer endpoint unreachable to the upper layer (and 5859 * thus the association enters the CLOSED state). The reception of any 5860 * packet from its peer (i.e. as the peer sends all of its queued DATA 5861 * chunks) should clear the endpoint's retransmission count and restart 5862 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5863 * all of its queued DATA chunks that have not yet been sent. 5864 */ 5865 enum sctp_disposition sctp_sf_t2_timer_expire( 5866 struct net *net, 5867 const struct sctp_endpoint *ep, 5868 const struct sctp_association *asoc, 5869 const union sctp_subtype type, 5870 void *arg, 5871 struct sctp_cmd_seq *commands) 5872 { 5873 struct sctp_chunk *reply = NULL; 5874 5875 pr_debug("%s: timer T2 expired\n", __func__); 5876 5877 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5878 5879 ((struct sctp_association *)asoc)->shutdown_retries++; 5880 5881 if (asoc->overall_error_count >= asoc->max_retrans) { 5882 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5883 SCTP_ERROR(ETIMEDOUT)); 5884 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5885 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5886 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5887 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5888 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5889 return SCTP_DISPOSITION_DELETE_TCB; 5890 } 5891 5892 switch (asoc->state) { 5893 case SCTP_STATE_SHUTDOWN_SENT: 5894 reply = sctp_make_shutdown(asoc, NULL); 5895 break; 5896 5897 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5898 reply = sctp_make_shutdown_ack(asoc, NULL); 5899 break; 5900 5901 default: 5902 BUG(); 5903 break; 5904 } 5905 5906 if (!reply) 5907 goto nomem; 5908 5909 /* Do some failure management (Section 8.2). 5910 * If we remove the transport an SHUTDOWN was last sent to, don't 5911 * do failure management. 5912 */ 5913 if (asoc->shutdown_last_sent_to) 5914 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5915 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5916 5917 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5918 * the T2-shutdown timer. 5919 */ 5920 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5921 5922 /* Restart the T2-shutdown timer. */ 5923 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5924 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5925 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5926 return SCTP_DISPOSITION_CONSUME; 5927 5928 nomem: 5929 return SCTP_DISPOSITION_NOMEM; 5930 } 5931 5932 /* 5933 * ADDIP Section 4.1 ASCONF CHunk Procedures 5934 * If the T4 RTO timer expires the endpoint should do B1 to B5 5935 */ 5936 enum sctp_disposition sctp_sf_t4_timer_expire( 5937 struct net *net, 5938 const struct sctp_endpoint *ep, 5939 const struct sctp_association *asoc, 5940 const union sctp_subtype type, 5941 void *arg, 5942 struct sctp_cmd_seq *commands) 5943 { 5944 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5945 struct sctp_transport *transport = chunk->transport; 5946 5947 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5948 5949 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5950 * detection on the appropriate destination address as defined in 5951 * RFC2960 [5] section 8.1 and 8.2. 5952 */ 5953 if (transport) 5954 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5955 SCTP_TRANSPORT(transport)); 5956 5957 /* Reconfig T4 timer and transport. */ 5958 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5959 5960 /* ADDIP 4.1 B2) Increment the association error counters and perform 5961 * endpoint failure detection on the association as defined in 5962 * RFC2960 [5] section 8.1 and 8.2. 5963 * association error counter is incremented in SCTP_CMD_STRIKE. 5964 */ 5965 if (asoc->overall_error_count >= asoc->max_retrans) { 5966 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5967 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5968 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5969 SCTP_ERROR(ETIMEDOUT)); 5970 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5971 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5972 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5973 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5974 return SCTP_DISPOSITION_ABORT; 5975 } 5976 5977 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5978 * the ASCONF chunk was sent by doubling the RTO timer value. 5979 * This is done in SCTP_CMD_STRIKE. 5980 */ 5981 5982 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5983 * choose an alternate destination address (please refer to RFC2960 5984 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5985 * chunk, it MUST be the same (including its serial number) as the last 5986 * ASCONF sent. 5987 */ 5988 sctp_chunk_hold(asoc->addip_last_asconf); 5989 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5990 SCTP_CHUNK(asoc->addip_last_asconf)); 5991 5992 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5993 * destination is selected, then the RTO used will be that of the new 5994 * destination address. 5995 */ 5996 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5997 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5998 5999 return SCTP_DISPOSITION_CONSUME; 6000 } 6001 6002 /* sctpimpguide-05 Section 2.12.2 6003 * The sender of the SHUTDOWN MAY also start an overall guard timer 6004 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6005 * At the expiration of this timer the sender SHOULD abort the association 6006 * by sending an ABORT chunk. 6007 */ 6008 enum sctp_disposition sctp_sf_t5_timer_expire( 6009 struct net *net, 6010 const struct sctp_endpoint *ep, 6011 const struct sctp_association *asoc, 6012 const union sctp_subtype type, 6013 void *arg, 6014 struct sctp_cmd_seq *commands) 6015 { 6016 struct sctp_chunk *reply = NULL; 6017 6018 pr_debug("%s: timer T5 expired\n", __func__); 6019 6020 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6021 6022 reply = sctp_make_abort(asoc, NULL, 0); 6023 if (!reply) 6024 goto nomem; 6025 6026 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6027 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6028 SCTP_ERROR(ETIMEDOUT)); 6029 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6030 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6031 6032 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6033 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6034 6035 return SCTP_DISPOSITION_DELETE_TCB; 6036 nomem: 6037 return SCTP_DISPOSITION_NOMEM; 6038 } 6039 6040 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6041 * the association is automatically closed by starting the shutdown process. 6042 * The work that needs to be done is same as when SHUTDOWN is initiated by 6043 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6044 */ 6045 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6046 struct net *net, 6047 const struct sctp_endpoint *ep, 6048 const struct sctp_association *asoc, 6049 const union sctp_subtype type, 6050 void *arg, 6051 struct sctp_cmd_seq *commands) 6052 { 6053 enum sctp_disposition disposition; 6054 6055 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6056 6057 /* From 9.2 Shutdown of an Association 6058 * Upon receipt of the SHUTDOWN primitive from its upper 6059 * layer, the endpoint enters SHUTDOWN-PENDING state and 6060 * remains there until all outstanding data has been 6061 * acknowledged by its peer. The endpoint accepts no new data 6062 * from its upper layer, but retransmits data to the far end 6063 * if necessary to fill gaps. 6064 */ 6065 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6066 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6067 6068 disposition = SCTP_DISPOSITION_CONSUME; 6069 if (sctp_outq_is_empty(&asoc->outqueue)) { 6070 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6071 arg, commands); 6072 } 6073 6074 return disposition; 6075 } 6076 6077 /***************************************************************************** 6078 * These are sa state functions which could apply to all types of events. 6079 ****************************************************************************/ 6080 6081 /* 6082 * This table entry is not implemented. 6083 * 6084 * Inputs 6085 * (endpoint, asoc, chunk) 6086 * 6087 * The return value is the disposition of the chunk. 6088 */ 6089 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6090 const struct sctp_endpoint *ep, 6091 const struct sctp_association *asoc, 6092 const union sctp_subtype type, 6093 void *arg, struct sctp_cmd_seq *commands) 6094 { 6095 return SCTP_DISPOSITION_NOT_IMPL; 6096 } 6097 6098 /* 6099 * This table entry represents a bug. 6100 * 6101 * Inputs 6102 * (endpoint, asoc, chunk) 6103 * 6104 * The return value is the disposition of the chunk. 6105 */ 6106 enum sctp_disposition sctp_sf_bug(struct net *net, 6107 const struct sctp_endpoint *ep, 6108 const struct sctp_association *asoc, 6109 const union sctp_subtype type, 6110 void *arg, struct sctp_cmd_seq *commands) 6111 { 6112 return SCTP_DISPOSITION_BUG; 6113 } 6114 6115 /* 6116 * This table entry represents the firing of a timer in the wrong state. 6117 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6118 * when the association is in the wrong state. This event should 6119 * be ignored, so as to prevent any rearming of the timer. 6120 * 6121 * Inputs 6122 * (endpoint, asoc, chunk) 6123 * 6124 * The return value is the disposition of the chunk. 6125 */ 6126 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6127 const struct sctp_endpoint *ep, 6128 const struct sctp_association *asoc, 6129 const union sctp_subtype type, 6130 void *arg, 6131 struct sctp_cmd_seq *commands) 6132 { 6133 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6134 6135 return SCTP_DISPOSITION_CONSUME; 6136 } 6137 6138 /******************************************************************** 6139 * 2nd Level Abstractions 6140 ********************************************************************/ 6141 6142 /* Pull the SACK chunk based on the SACK header. */ 6143 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6144 { 6145 struct sctp_sackhdr *sack; 6146 __u16 num_dup_tsns; 6147 unsigned int len; 6148 __u16 num_blocks; 6149 6150 /* Protect ourselves from reading too far into 6151 * the skb from a bogus sender. 6152 */ 6153 sack = (struct sctp_sackhdr *) chunk->skb->data; 6154 6155 num_blocks = ntohs(sack->num_gap_ack_blocks); 6156 num_dup_tsns = ntohs(sack->num_dup_tsns); 6157 len = sizeof(struct sctp_sackhdr); 6158 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6159 if (len > chunk->skb->len) 6160 return NULL; 6161 6162 skb_pull(chunk->skb, len); 6163 6164 return sack; 6165 } 6166 6167 /* Create an ABORT packet to be sent as a response, with the specified 6168 * error causes. 6169 */ 6170 static struct sctp_packet *sctp_abort_pkt_new( 6171 struct net *net, 6172 const struct sctp_endpoint *ep, 6173 const struct sctp_association *asoc, 6174 struct sctp_chunk *chunk, 6175 const void *payload, size_t paylen) 6176 { 6177 struct sctp_packet *packet; 6178 struct sctp_chunk *abort; 6179 6180 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6181 6182 if (packet) { 6183 /* Make an ABORT. 6184 * The T bit will be set if the asoc is NULL. 6185 */ 6186 abort = sctp_make_abort(asoc, chunk, paylen); 6187 if (!abort) { 6188 sctp_ootb_pkt_free(packet); 6189 return NULL; 6190 } 6191 6192 /* Reflect vtag if T-Bit is set */ 6193 if (sctp_test_T_bit(abort)) 6194 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6195 6196 /* Add specified error causes, i.e., payload, to the 6197 * end of the chunk. 6198 */ 6199 sctp_addto_chunk(abort, paylen, payload); 6200 6201 /* Set the skb to the belonging sock for accounting. */ 6202 abort->skb->sk = ep->base.sk; 6203 6204 sctp_packet_append_chunk(packet, abort); 6205 6206 } 6207 6208 return packet; 6209 } 6210 6211 /* Allocate a packet for responding in the OOTB conditions. */ 6212 static struct sctp_packet *sctp_ootb_pkt_new( 6213 struct net *net, 6214 const struct sctp_association *asoc, 6215 const struct sctp_chunk *chunk) 6216 { 6217 struct sctp_transport *transport; 6218 struct sctp_packet *packet; 6219 __u16 sport, dport; 6220 __u32 vtag; 6221 6222 /* Get the source and destination port from the inbound packet. */ 6223 sport = ntohs(chunk->sctp_hdr->dest); 6224 dport = ntohs(chunk->sctp_hdr->source); 6225 6226 /* The V-tag is going to be the same as the inbound packet if no 6227 * association exists, otherwise, use the peer's vtag. 6228 */ 6229 if (asoc) { 6230 /* Special case the INIT-ACK as there is no peer's vtag 6231 * yet. 6232 */ 6233 switch (chunk->chunk_hdr->type) { 6234 case SCTP_CID_INIT_ACK: 6235 { 6236 struct sctp_initack_chunk *initack; 6237 6238 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6239 vtag = ntohl(initack->init_hdr.init_tag); 6240 break; 6241 } 6242 default: 6243 vtag = asoc->peer.i.init_tag; 6244 break; 6245 } 6246 } else { 6247 /* Special case the INIT and stale COOKIE_ECHO as there is no 6248 * vtag yet. 6249 */ 6250 switch (chunk->chunk_hdr->type) { 6251 case SCTP_CID_INIT: 6252 { 6253 struct sctp_init_chunk *init; 6254 6255 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6256 vtag = ntohl(init->init_hdr.init_tag); 6257 break; 6258 } 6259 default: 6260 vtag = ntohl(chunk->sctp_hdr->vtag); 6261 break; 6262 } 6263 } 6264 6265 /* Make a transport for the bucket, Eliza... */ 6266 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6267 if (!transport) 6268 goto nomem; 6269 6270 /* Cache a route for the transport with the chunk's destination as 6271 * the source address. 6272 */ 6273 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6274 sctp_sk(net->sctp.ctl_sock)); 6275 6276 packet = &transport->packet; 6277 sctp_packet_init(packet, transport, sport, dport); 6278 sctp_packet_config(packet, vtag, 0); 6279 6280 return packet; 6281 6282 nomem: 6283 return NULL; 6284 } 6285 6286 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6287 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6288 { 6289 sctp_transport_free(packet->transport); 6290 } 6291 6292 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6293 static void sctp_send_stale_cookie_err(struct net *net, 6294 const struct sctp_endpoint *ep, 6295 const struct sctp_association *asoc, 6296 const struct sctp_chunk *chunk, 6297 struct sctp_cmd_seq *commands, 6298 struct sctp_chunk *err_chunk) 6299 { 6300 struct sctp_packet *packet; 6301 6302 if (err_chunk) { 6303 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6304 if (packet) { 6305 struct sctp_signed_cookie *cookie; 6306 6307 /* Override the OOTB vtag from the cookie. */ 6308 cookie = chunk->subh.cookie_hdr; 6309 packet->vtag = cookie->c.peer_vtag; 6310 6311 /* Set the skb to the belonging sock for accounting. */ 6312 err_chunk->skb->sk = ep->base.sk; 6313 sctp_packet_append_chunk(packet, err_chunk); 6314 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6315 SCTP_PACKET(packet)); 6316 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6317 } else 6318 sctp_chunk_free (err_chunk); 6319 } 6320 } 6321 6322 6323 /* Process a data chunk */ 6324 static int sctp_eat_data(const struct sctp_association *asoc, 6325 struct sctp_chunk *chunk, 6326 struct sctp_cmd_seq *commands) 6327 { 6328 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6329 struct sock *sk = asoc->base.sk; 6330 struct net *net = sock_net(sk); 6331 struct sctp_datahdr *data_hdr; 6332 struct sctp_chunk *err; 6333 enum sctp_verb deliver; 6334 size_t datalen; 6335 __u32 tsn; 6336 int tmp; 6337 6338 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6339 chunk->subh.data_hdr = data_hdr; 6340 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6341 6342 tsn = ntohl(data_hdr->tsn); 6343 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6344 6345 /* ASSERT: Now skb->data is really the user data. */ 6346 6347 /* Process ECN based congestion. 6348 * 6349 * Since the chunk structure is reused for all chunks within 6350 * a packet, we use ecn_ce_done to track if we've already 6351 * done CE processing for this packet. 6352 * 6353 * We need to do ECN processing even if we plan to discard the 6354 * chunk later. 6355 */ 6356 6357 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6358 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6359 chunk->ecn_ce_done = 1; 6360 6361 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6362 /* Do real work as sideffect. */ 6363 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6364 SCTP_U32(tsn)); 6365 } 6366 } 6367 6368 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6369 if (tmp < 0) { 6370 /* The TSN is too high--silently discard the chunk and 6371 * count on it getting retransmitted later. 6372 */ 6373 if (chunk->asoc) 6374 chunk->asoc->stats.outofseqtsns++; 6375 return SCTP_IERROR_HIGH_TSN; 6376 } else if (tmp > 0) { 6377 /* This is a duplicate. Record it. */ 6378 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6379 return SCTP_IERROR_DUP_TSN; 6380 } 6381 6382 /* This is a new TSN. */ 6383 6384 /* Discard if there is no room in the receive window. 6385 * Actually, allow a little bit of overflow (up to a MTU). 6386 */ 6387 datalen = ntohs(chunk->chunk_hdr->length); 6388 datalen -= sctp_datachk_len(&asoc->stream); 6389 6390 deliver = SCTP_CMD_CHUNK_ULP; 6391 6392 /* Think about partial delivery. */ 6393 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6394 6395 /* Even if we don't accept this chunk there is 6396 * memory pressure. 6397 */ 6398 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6399 } 6400 6401 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6402 * seems a bit troublesome in that frag_point varies based on 6403 * PMTU. In cases, such as loopback, this might be a rather 6404 * large spill over. 6405 */ 6406 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6407 (datalen > asoc->rwnd + asoc->frag_point))) { 6408 6409 /* If this is the next TSN, consider reneging to make 6410 * room. Note: Playing nice with a confused sender. A 6411 * malicious sender can still eat up all our buffer 6412 * space and in the future we may want to detect and 6413 * do more drastic reneging. 6414 */ 6415 if (sctp_tsnmap_has_gap(map) && 6416 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6417 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6418 deliver = SCTP_CMD_RENEGE; 6419 } else { 6420 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6421 __func__, tsn, datalen, asoc->rwnd); 6422 6423 return SCTP_IERROR_IGNORE_TSN; 6424 } 6425 } 6426 6427 /* 6428 * Also try to renege to limit our memory usage in the event that 6429 * we are under memory pressure 6430 * If we can't renege, don't worry about it, the sk_rmem_schedule 6431 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6432 * memory usage too much 6433 */ 6434 if (sk_under_memory_pressure(sk)) { 6435 if (sctp_tsnmap_has_gap(map) && 6436 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6437 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6438 __func__, tsn); 6439 deliver = SCTP_CMD_RENEGE; 6440 } else { 6441 sk_mem_reclaim(sk); 6442 } 6443 } 6444 6445 /* 6446 * Section 3.3.10.9 No User Data (9) 6447 * 6448 * Cause of error 6449 * --------------- 6450 * No User Data: This error cause is returned to the originator of a 6451 * DATA chunk if a received DATA chunk has no user data. 6452 */ 6453 if (unlikely(0 == datalen)) { 6454 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6455 if (err) { 6456 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6457 SCTP_CHUNK(err)); 6458 } 6459 /* We are going to ABORT, so we might as well stop 6460 * processing the rest of the chunks in the packet. 6461 */ 6462 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6463 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6464 SCTP_ERROR(ECONNABORTED)); 6465 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6466 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6467 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6468 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6469 return SCTP_IERROR_NO_DATA; 6470 } 6471 6472 chunk->data_accepted = 1; 6473 6474 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6475 * if we renege and the chunk arrives again. 6476 */ 6477 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6478 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6479 if (chunk->asoc) 6480 chunk->asoc->stats.iuodchunks++; 6481 } else { 6482 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6483 if (chunk->asoc) 6484 chunk->asoc->stats.iodchunks++; 6485 } 6486 6487 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6488 * 6489 * If an endpoint receive a DATA chunk with an invalid stream 6490 * identifier, it shall acknowledge the reception of the DATA chunk 6491 * following the normal procedure, immediately send an ERROR chunk 6492 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6493 * and discard the DATA chunk. 6494 */ 6495 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6496 /* Mark tsn as received even though we drop it */ 6497 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6498 6499 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6500 &data_hdr->stream, 6501 sizeof(data_hdr->stream), 6502 sizeof(u16)); 6503 if (err) 6504 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6505 SCTP_CHUNK(err)); 6506 return SCTP_IERROR_BAD_STREAM; 6507 } 6508 6509 /* Check to see if the SSN is possible for this TSN. 6510 * The biggest gap we can record is 4K wide. Since SSNs wrap 6511 * at an unsigned short, there is no way that an SSN can 6512 * wrap and for a valid TSN. We can simply check if the current 6513 * SSN is smaller then the next expected one. If it is, it wrapped 6514 * and is invalid. 6515 */ 6516 if (!asoc->stream.si->validate_data(chunk)) 6517 return SCTP_IERROR_PROTO_VIOLATION; 6518 6519 /* Send the data up to the user. Note: Schedule the 6520 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6521 * chunk needs the updated rwnd. 6522 */ 6523 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6524 6525 return SCTP_IERROR_NO_ERROR; 6526 } 6527