1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, see 26 * <http://www.gnu.org/licenses/>. 27 * 28 * Please send any bug reports or fixes you make to the 29 * email address(es): 30 * lksctp developers <linux-sctp@vger.kernel.org> 31 * 32 * Written or modified by: 33 * La Monte H.P. Yarroll <piggy@acm.org> 34 * Karl Knutson <karl@athena.chicago.il.us> 35 * Mathew Kotowsky <kotowsky@sctp.org> 36 * Sridhar Samudrala <samudrala@us.ibm.com> 37 * Jon Grimm <jgrimm@us.ibm.com> 38 * Hui Huang <hui.huang@nokia.com> 39 * Dajiang Zhang <dajiang.zhang@nokia.com> 40 * Daisy Chang <daisyc@us.ibm.com> 41 * Ardelle Fan <ardelle.fan@intel.com> 42 * Ryan Layer <rmlayer@us.ibm.com> 43 * Kevin Gao <kevin.gao@intel.com> 44 */ 45 46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 47 48 #include <linux/types.h> 49 #include <linux/kernel.h> 50 #include <linux/ip.h> 51 #include <linux/ipv6.h> 52 #include <linux/net.h> 53 #include <linux/inet.h> 54 #include <linux/slab.h> 55 #include <net/sock.h> 56 #include <net/inet_ecn.h> 57 #include <linux/skbuff.h> 58 #include <net/sctp/sctp.h> 59 #include <net/sctp/sm.h> 60 #include <net/sctp/structs.h> 61 62 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 63 const struct sctp_endpoint *ep, 64 const struct sctp_association *asoc, 65 struct sctp_chunk *chunk, 66 const void *payload, 67 size_t paylen); 68 static int sctp_eat_data(const struct sctp_association *asoc, 69 struct sctp_chunk *chunk, 70 sctp_cmd_seq_t *commands); 71 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 72 const struct sctp_association *asoc, 73 const struct sctp_chunk *chunk); 74 static void sctp_send_stale_cookie_err(struct net *net, 75 const struct sctp_endpoint *ep, 76 const struct sctp_association *asoc, 77 const struct sctp_chunk *chunk, 78 sctp_cmd_seq_t *commands, 79 struct sctp_chunk *err_chunk); 80 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 81 const struct sctp_endpoint *ep, 82 const struct sctp_association *asoc, 83 const sctp_subtype_t type, 84 void *arg, 85 sctp_cmd_seq_t *commands); 86 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const sctp_subtype_t type, 90 void *arg, 91 sctp_cmd_seq_t *commands); 92 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 93 const struct sctp_endpoint *ep, 94 const struct sctp_association *asoc, 95 const sctp_subtype_t type, 96 void *arg, 97 sctp_cmd_seq_t *commands); 98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 99 100 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 101 sctp_cmd_seq_t *commands, 102 __be16 error, int sk_err, 103 const struct sctp_association *asoc, 104 struct sctp_transport *transport); 105 106 static sctp_disposition_t sctp_sf_abort_violation( 107 struct net *net, 108 const struct sctp_endpoint *ep, 109 const struct sctp_association *asoc, 110 void *arg, 111 sctp_cmd_seq_t *commands, 112 const __u8 *payload, 113 const size_t paylen); 114 115 static sctp_disposition_t sctp_sf_violation_chunklen( 116 struct net *net, 117 const struct sctp_endpoint *ep, 118 const struct sctp_association *asoc, 119 const sctp_subtype_t type, 120 void *arg, 121 sctp_cmd_seq_t *commands); 122 123 static sctp_disposition_t sctp_sf_violation_paramlen( 124 struct net *net, 125 const struct sctp_endpoint *ep, 126 const struct sctp_association *asoc, 127 const sctp_subtype_t type, 128 void *arg, void *ext, 129 sctp_cmd_seq_t *commands); 130 131 static sctp_disposition_t sctp_sf_violation_ctsn( 132 struct net *net, 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const sctp_subtype_t type, 136 void *arg, 137 sctp_cmd_seq_t *commands); 138 139 static sctp_disposition_t sctp_sf_violation_chunk( 140 struct net *net, 141 const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const sctp_subtype_t type, 144 void *arg, 145 sctp_cmd_seq_t *commands); 146 147 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 148 const struct sctp_endpoint *ep, 149 const struct sctp_association *asoc, 150 const sctp_subtype_t type, 151 struct sctp_chunk *chunk); 152 153 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 154 const struct sctp_endpoint *ep, 155 const struct sctp_association *asoc, 156 const sctp_subtype_t type, 157 void *arg, 158 sctp_cmd_seq_t *commands); 159 160 /* Small helper function that checks if the chunk length 161 * is of the appropriate length. The 'required_length' argument 162 * is set to be the size of a specific chunk we are testing. 163 * Return Values: true = Valid length 164 * false = Invalid length 165 * 166 */ 167 static inline bool 168 sctp_chunk_length_valid(struct sctp_chunk *chunk, __u16 required_length) 169 { 170 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 171 172 /* Previously already marked? */ 173 if (unlikely(chunk->pdiscard)) 174 return false; 175 if (unlikely(chunk_length < required_length)) 176 return false; 177 178 return true; 179 } 180 181 /********************************************************** 182 * These are the state functions for handling chunk events. 183 **********************************************************/ 184 185 /* 186 * Process the final SHUTDOWN COMPLETE. 187 * 188 * Section: 4 (C) (diagram), 9.2 189 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 190 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 191 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 192 * should stop the T2-shutdown timer and remove all knowledge of the 193 * association (and thus the association enters the CLOSED state). 194 * 195 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 196 * C) Rules for packet carrying SHUTDOWN COMPLETE: 197 * ... 198 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 199 * if the Verification Tag field of the packet matches its own tag and 200 * the T bit is not set 201 * OR 202 * it is set to its peer's tag and the T bit is set in the Chunk 203 * Flags. 204 * Otherwise, the receiver MUST silently discard the packet 205 * and take no further action. An endpoint MUST ignore the 206 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 207 * 208 * Inputs 209 * (endpoint, asoc, chunk) 210 * 211 * Outputs 212 * (asoc, reply_msg, msg_up, timers, counters) 213 * 214 * The return value is the disposition of the chunk. 215 */ 216 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 217 const struct sctp_endpoint *ep, 218 const struct sctp_association *asoc, 219 const sctp_subtype_t type, 220 void *arg, 221 sctp_cmd_seq_t *commands) 222 { 223 struct sctp_chunk *chunk = arg; 224 struct sctp_ulpevent *ev; 225 226 if (!sctp_vtag_verify_either(chunk, asoc)) 227 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 228 229 /* RFC 2960 6.10 Bundling 230 * 231 * An endpoint MUST NOT bundle INIT, INIT ACK or 232 * SHUTDOWN COMPLETE with any other chunks. 233 */ 234 if (!chunk->singleton) 235 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 236 237 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 238 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 239 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 240 commands); 241 242 /* RFC 2960 10.2 SCTP-to-ULP 243 * 244 * H) SHUTDOWN COMPLETE notification 245 * 246 * When SCTP completes the shutdown procedures (section 9.2) this 247 * notification is passed to the upper layer. 248 */ 249 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 250 0, 0, 0, NULL, GFP_ATOMIC); 251 if (ev) 252 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 253 SCTP_ULPEVENT(ev)); 254 255 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 256 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 257 * not the chunk should be discarded. If the endpoint is in 258 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 259 * T2-shutdown timer and remove all knowledge of the 260 * association (and thus the association enters the CLOSED 261 * state). 262 */ 263 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 264 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 265 266 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 267 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 268 269 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 270 SCTP_STATE(SCTP_STATE_CLOSED)); 271 272 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 273 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 274 275 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 276 277 return SCTP_DISPOSITION_DELETE_TCB; 278 } 279 280 /* 281 * Respond to a normal INIT chunk. 282 * We are the side that is being asked for an association. 283 * 284 * Section: 5.1 Normal Establishment of an Association, B 285 * B) "Z" shall respond immediately with an INIT ACK chunk. The 286 * destination IP address of the INIT ACK MUST be set to the source 287 * IP address of the INIT to which this INIT ACK is responding. In 288 * the response, besides filling in other parameters, "Z" must set the 289 * Verification Tag field to Tag_A, and also provide its own 290 * Verification Tag (Tag_Z) in the Initiate Tag field. 291 * 292 * Verification Tag: Must be 0. 293 * 294 * Inputs 295 * (endpoint, asoc, chunk) 296 * 297 * Outputs 298 * (asoc, reply_msg, msg_up, timers, counters) 299 * 300 * The return value is the disposition of the chunk. 301 */ 302 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 303 const struct sctp_endpoint *ep, 304 const struct sctp_association *asoc, 305 const sctp_subtype_t type, 306 void *arg, 307 sctp_cmd_seq_t *commands) 308 { 309 struct sctp_chunk *chunk = arg; 310 struct sctp_chunk *repl; 311 struct sctp_association *new_asoc; 312 struct sctp_chunk *err_chunk; 313 struct sctp_packet *packet; 314 sctp_unrecognized_param_t *unk_param; 315 int len; 316 317 /* 6.10 Bundling 318 * An endpoint MUST NOT bundle INIT, INIT ACK or 319 * SHUTDOWN COMPLETE with any other chunks. 320 * 321 * IG Section 2.11.2 322 * Furthermore, we require that the receiver of an INIT chunk MUST 323 * enforce these rules by silently discarding an arriving packet 324 * with an INIT chunk that is bundled with other chunks. 325 */ 326 if (!chunk->singleton) 327 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 328 329 /* If the packet is an OOTB packet which is temporarily on the 330 * control endpoint, respond with an ABORT. 331 */ 332 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 333 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 334 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 335 } 336 337 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 338 * Tag. 339 */ 340 if (chunk->sctp_hdr->vtag != 0) 341 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 342 343 /* Make sure that the INIT chunk has a valid length. 344 * Normally, this would cause an ABORT with a Protocol Violation 345 * error, but since we don't have an association, we'll 346 * just discard the packet. 347 */ 348 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 349 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 350 351 /* If the INIT is coming toward a closing socket, we'll send back 352 * and ABORT. Essentially, this catches the race of INIT being 353 * backloged to the socket at the same time as the user isses close(). 354 * Since the socket and all its associations are going away, we 355 * can treat this OOTB 356 */ 357 if (sctp_sstate(ep->base.sk, CLOSING)) 358 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 359 360 /* Verify the INIT chunk before processing it. */ 361 err_chunk = NULL; 362 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 363 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 364 &err_chunk)) { 365 /* This chunk contains fatal error. It is to be discarded. 366 * Send an ABORT, with causes if there is any. 367 */ 368 if (err_chunk) { 369 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 370 (__u8 *)(err_chunk->chunk_hdr) + 371 sizeof(sctp_chunkhdr_t), 372 ntohs(err_chunk->chunk_hdr->length) - 373 sizeof(sctp_chunkhdr_t)); 374 375 sctp_chunk_free(err_chunk); 376 377 if (packet) { 378 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 379 SCTP_PACKET(packet)); 380 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 381 return SCTP_DISPOSITION_CONSUME; 382 } else { 383 return SCTP_DISPOSITION_NOMEM; 384 } 385 } else { 386 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 387 commands); 388 } 389 } 390 391 /* Grab the INIT header. */ 392 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 393 394 /* Tag the variable length parameters. */ 395 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 396 397 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 398 if (!new_asoc) 399 goto nomem; 400 401 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 402 sctp_scope(sctp_source(chunk)), 403 GFP_ATOMIC) < 0) 404 goto nomem_init; 405 406 /* The call, sctp_process_init(), can fail on memory allocation. */ 407 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 408 (sctp_init_chunk_t *)chunk->chunk_hdr, 409 GFP_ATOMIC)) 410 goto nomem_init; 411 412 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 413 414 /* If there are errors need to be reported for unknown parameters, 415 * make sure to reserve enough room in the INIT ACK for them. 416 */ 417 len = 0; 418 if (err_chunk) 419 len = ntohs(err_chunk->chunk_hdr->length) - 420 sizeof(sctp_chunkhdr_t); 421 422 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 423 if (!repl) 424 goto nomem_init; 425 426 /* If there are errors need to be reported for unknown parameters, 427 * include them in the outgoing INIT ACK as "Unrecognized parameter" 428 * parameter. 429 */ 430 if (err_chunk) { 431 /* Get the "Unrecognized parameter" parameter(s) out of the 432 * ERROR chunk generated by sctp_verify_init(). Since the 433 * error cause code for "unknown parameter" and the 434 * "Unrecognized parameter" type is the same, we can 435 * construct the parameters in INIT ACK by copying the 436 * ERROR causes over. 437 */ 438 unk_param = (sctp_unrecognized_param_t *) 439 ((__u8 *)(err_chunk->chunk_hdr) + 440 sizeof(sctp_chunkhdr_t)); 441 /* Replace the cause code with the "Unrecognized parameter" 442 * parameter type. 443 */ 444 sctp_addto_chunk(repl, len, unk_param); 445 sctp_chunk_free(err_chunk); 446 } 447 448 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 449 450 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 451 452 /* 453 * Note: After sending out INIT ACK with the State Cookie parameter, 454 * "Z" MUST NOT allocate any resources, nor keep any states for the 455 * new association. Otherwise, "Z" will be vulnerable to resource 456 * attacks. 457 */ 458 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 459 460 return SCTP_DISPOSITION_DELETE_TCB; 461 462 nomem_init: 463 sctp_association_free(new_asoc); 464 nomem: 465 if (err_chunk) 466 sctp_chunk_free(err_chunk); 467 return SCTP_DISPOSITION_NOMEM; 468 } 469 470 /* 471 * Respond to a normal INIT ACK chunk. 472 * We are the side that is initiating the association. 473 * 474 * Section: 5.1 Normal Establishment of an Association, C 475 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 476 * timer and leave COOKIE-WAIT state. "A" shall then send the State 477 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 478 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 479 * 480 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 481 * DATA chunks, but it MUST be the first chunk in the packet and 482 * until the COOKIE ACK is returned the sender MUST NOT send any 483 * other packets to the peer. 484 * 485 * Verification Tag: 3.3.3 486 * If the value of the Initiate Tag in a received INIT ACK chunk is 487 * found to be 0, the receiver MUST treat it as an error and close the 488 * association by transmitting an ABORT. 489 * 490 * Inputs 491 * (endpoint, asoc, chunk) 492 * 493 * Outputs 494 * (asoc, reply_msg, msg_up, timers, counters) 495 * 496 * The return value is the disposition of the chunk. 497 */ 498 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 499 const struct sctp_endpoint *ep, 500 const struct sctp_association *asoc, 501 const sctp_subtype_t type, 502 void *arg, 503 sctp_cmd_seq_t *commands) 504 { 505 struct sctp_chunk *chunk = arg; 506 sctp_init_chunk_t *initchunk; 507 struct sctp_chunk *err_chunk; 508 struct sctp_packet *packet; 509 510 if (!sctp_vtag_verify(chunk, asoc)) 511 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 512 513 /* 6.10 Bundling 514 * An endpoint MUST NOT bundle INIT, INIT ACK or 515 * SHUTDOWN COMPLETE with any other chunks. 516 */ 517 if (!chunk->singleton) 518 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 519 520 /* Make sure that the INIT-ACK chunk has a valid length */ 521 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 522 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 523 commands); 524 /* Grab the INIT header. */ 525 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 526 527 /* Verify the INIT chunk before processing it. */ 528 err_chunk = NULL; 529 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 530 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 531 &err_chunk)) { 532 533 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 534 535 /* This chunk contains fatal error. It is to be discarded. 536 * Send an ABORT, with causes. If there are no causes, 537 * then there wasn't enough memory. Just terminate 538 * the association. 539 */ 540 if (err_chunk) { 541 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 542 (__u8 *)(err_chunk->chunk_hdr) + 543 sizeof(sctp_chunkhdr_t), 544 ntohs(err_chunk->chunk_hdr->length) - 545 sizeof(sctp_chunkhdr_t)); 546 547 sctp_chunk_free(err_chunk); 548 549 if (packet) { 550 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 551 SCTP_PACKET(packet)); 552 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 553 error = SCTP_ERROR_INV_PARAM; 554 } 555 } 556 557 /* SCTP-AUTH, Section 6.3: 558 * It should be noted that if the receiver wants to tear 559 * down an association in an authenticated way only, the 560 * handling of malformed packets should not result in 561 * tearing down the association. 562 * 563 * This means that if we only want to abort associations 564 * in an authenticated way (i.e AUTH+ABORT), then we 565 * can't destroy this association just because the packet 566 * was malformed. 567 */ 568 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 569 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 570 571 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 572 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 573 asoc, chunk->transport); 574 } 575 576 /* Tag the variable length parameters. Note that we never 577 * convert the parameters in an INIT chunk. 578 */ 579 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 580 581 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 582 583 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 584 SCTP_PEER_INIT(initchunk)); 585 586 /* Reset init error count upon receipt of INIT-ACK. */ 587 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 588 589 /* 5.1 C) "A" shall stop the T1-init timer and leave 590 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 591 * timer, and enter the COOKIE-ECHOED state. 592 */ 593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 595 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 596 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 597 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 598 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 599 600 /* SCTP-AUTH: genereate the assocition shared keys so that 601 * we can potentially signe the COOKIE-ECHO. 602 */ 603 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 604 605 /* 5.1 C) "A" shall then send the State Cookie received in the 606 * INIT ACK chunk in a COOKIE ECHO chunk, ... 607 */ 608 /* If there is any errors to report, send the ERROR chunk generated 609 * for unknown parameters as well. 610 */ 611 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 612 SCTP_CHUNK(err_chunk)); 613 614 return SCTP_DISPOSITION_CONSUME; 615 } 616 617 /* 618 * Respond to a normal COOKIE ECHO chunk. 619 * We are the side that is being asked for an association. 620 * 621 * Section: 5.1 Normal Establishment of an Association, D 622 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 623 * with a COOKIE ACK chunk after building a TCB and moving to 624 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 625 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 626 * chunk MUST be the first chunk in the packet. 627 * 628 * IMPLEMENTATION NOTE: An implementation may choose to send the 629 * Communication Up notification to the SCTP user upon reception 630 * of a valid COOKIE ECHO chunk. 631 * 632 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 633 * D) Rules for packet carrying a COOKIE ECHO 634 * 635 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 636 * Initial Tag received in the INIT ACK. 637 * 638 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 639 * 640 * Inputs 641 * (endpoint, asoc, chunk) 642 * 643 * Outputs 644 * (asoc, reply_msg, msg_up, timers, counters) 645 * 646 * The return value is the disposition of the chunk. 647 */ 648 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 649 const struct sctp_endpoint *ep, 650 const struct sctp_association *asoc, 651 const sctp_subtype_t type, void *arg, 652 sctp_cmd_seq_t *commands) 653 { 654 struct sctp_chunk *chunk = arg; 655 struct sctp_association *new_asoc; 656 sctp_init_chunk_t *peer_init; 657 struct sctp_chunk *repl; 658 struct sctp_ulpevent *ev, *ai_ev = NULL; 659 int error = 0; 660 struct sctp_chunk *err_chk_p; 661 struct sock *sk; 662 663 /* If the packet is an OOTB packet which is temporarily on the 664 * control endpoint, respond with an ABORT. 665 */ 666 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 667 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 668 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 669 } 670 671 /* Make sure that the COOKIE_ECHO chunk has a valid length. 672 * In this case, we check that we have enough for at least a 673 * chunk header. More detailed verification is done 674 * in sctp_unpack_cookie(). 675 */ 676 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 677 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 678 679 /* If the endpoint is not listening or if the number of associations 680 * on the TCP-style socket exceed the max backlog, respond with an 681 * ABORT. 682 */ 683 sk = ep->base.sk; 684 if (!sctp_sstate(sk, LISTENING) || 685 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 686 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 687 688 /* "Decode" the chunk. We have no optional parameters so we 689 * are in good shape. 690 */ 691 chunk->subh.cookie_hdr = 692 (struct sctp_signed_cookie *)chunk->skb->data; 693 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 694 sizeof(sctp_chunkhdr_t))) 695 goto nomem; 696 697 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 698 * "Z" will reply with a COOKIE ACK chunk after building a TCB 699 * and moving to the ESTABLISHED state. 700 */ 701 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 702 &err_chk_p); 703 704 /* FIXME: 705 * If the re-build failed, what is the proper error path 706 * from here? 707 * 708 * [We should abort the association. --piggy] 709 */ 710 if (!new_asoc) { 711 /* FIXME: Several errors are possible. A bad cookie should 712 * be silently discarded, but think about logging it too. 713 */ 714 switch (error) { 715 case -SCTP_IERROR_NOMEM: 716 goto nomem; 717 718 case -SCTP_IERROR_STALE_COOKIE: 719 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 720 err_chk_p); 721 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 722 723 case -SCTP_IERROR_BAD_SIG: 724 default: 725 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 726 } 727 } 728 729 730 /* Delay state machine commands until later. 731 * 732 * Re-build the bind address for the association is done in 733 * the sctp_unpack_cookie() already. 734 */ 735 /* This is a brand-new association, so these are not yet side 736 * effects--it is safe to run them here. 737 */ 738 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 739 740 if (!sctp_process_init(new_asoc, chunk, 741 &chunk->subh.cookie_hdr->c.peer_addr, 742 peer_init, GFP_ATOMIC)) 743 goto nomem_init; 744 745 /* SCTP-AUTH: Now that we've populate required fields in 746 * sctp_process_init, set up the assocaition shared keys as 747 * necessary so that we can potentially authenticate the ACK 748 */ 749 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 750 if (error) 751 goto nomem_init; 752 753 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 754 * is supposed to be authenticated and we have to do delayed 755 * authentication. We've just recreated the association using 756 * the information in the cookie and now it's much easier to 757 * do the authentication. 758 */ 759 if (chunk->auth_chunk) { 760 struct sctp_chunk auth; 761 sctp_ierror_t ret; 762 763 /* Make sure that we and the peer are AUTH capable */ 764 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) { 765 sctp_association_free(new_asoc); 766 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 767 } 768 769 /* set-up our fake chunk so that we can process it */ 770 auth.skb = chunk->auth_chunk; 771 auth.asoc = chunk->asoc; 772 auth.sctp_hdr = chunk->sctp_hdr; 773 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 774 sizeof(sctp_chunkhdr_t)); 775 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 776 auth.transport = chunk->transport; 777 778 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 779 if (ret != SCTP_IERROR_NO_ERROR) { 780 sctp_association_free(new_asoc); 781 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 782 } 783 } 784 785 repl = sctp_make_cookie_ack(new_asoc, chunk); 786 if (!repl) 787 goto nomem_init; 788 789 /* RFC 2960 5.1 Normal Establishment of an Association 790 * 791 * D) IMPLEMENTATION NOTE: An implementation may choose to 792 * send the Communication Up notification to the SCTP user 793 * upon reception of a valid COOKIE ECHO chunk. 794 */ 795 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 796 new_asoc->c.sinit_num_ostreams, 797 new_asoc->c.sinit_max_instreams, 798 NULL, GFP_ATOMIC); 799 if (!ev) 800 goto nomem_ev; 801 802 /* Sockets API Draft Section 5.3.1.6 803 * When a peer sends a Adaptation Layer Indication parameter , SCTP 804 * delivers this notification to inform the application that of the 805 * peers requested adaptation layer. 806 */ 807 if (new_asoc->peer.adaptation_ind) { 808 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 809 GFP_ATOMIC); 810 if (!ai_ev) 811 goto nomem_aiev; 812 } 813 814 /* Add all the state machine commands now since we've created 815 * everything. This way we don't introduce memory corruptions 816 * during side-effect processing and correclty count established 817 * associations. 818 */ 819 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 820 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 821 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 822 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 823 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 824 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 825 826 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 827 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 828 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 829 830 /* This will send the COOKIE ACK */ 831 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 832 833 /* Queue the ASSOC_CHANGE event */ 834 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 835 836 /* Send up the Adaptation Layer Indication event */ 837 if (ai_ev) 838 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 839 SCTP_ULPEVENT(ai_ev)); 840 841 return SCTP_DISPOSITION_CONSUME; 842 843 nomem_aiev: 844 sctp_ulpevent_free(ev); 845 nomem_ev: 846 sctp_chunk_free(repl); 847 nomem_init: 848 sctp_association_free(new_asoc); 849 nomem: 850 return SCTP_DISPOSITION_NOMEM; 851 } 852 853 /* 854 * Respond to a normal COOKIE ACK chunk. 855 * We are the side that is asking for an association. 856 * 857 * RFC 2960 5.1 Normal Establishment of an Association 858 * 859 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 860 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 861 * timer. It may also notify its ULP about the successful 862 * establishment of the association with a Communication Up 863 * notification (see Section 10). 864 * 865 * Verification Tag: 866 * Inputs 867 * (endpoint, asoc, chunk) 868 * 869 * Outputs 870 * (asoc, reply_msg, msg_up, timers, counters) 871 * 872 * The return value is the disposition of the chunk. 873 */ 874 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 875 const struct sctp_endpoint *ep, 876 const struct sctp_association *asoc, 877 const sctp_subtype_t type, void *arg, 878 sctp_cmd_seq_t *commands) 879 { 880 struct sctp_chunk *chunk = arg; 881 struct sctp_ulpevent *ev; 882 883 if (!sctp_vtag_verify(chunk, asoc)) 884 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 885 886 /* Verify that the chunk length for the COOKIE-ACK is OK. 887 * If we don't do this, any bundled chunks may be junked. 888 */ 889 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 890 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 891 commands); 892 893 /* Reset init error count upon receipt of COOKIE-ACK, 894 * to avoid problems with the managemement of this 895 * counter in stale cookie situations when a transition back 896 * from the COOKIE-ECHOED state to the COOKIE-WAIT 897 * state is performed. 898 */ 899 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 900 901 /* RFC 2960 5.1 Normal Establishment of an Association 902 * 903 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 904 * from the COOKIE-ECHOED state to the ESTABLISHED state, 905 * stopping the T1-cookie timer. 906 */ 907 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 908 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 909 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 910 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 911 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 912 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 913 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 914 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 915 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 916 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 917 918 /* It may also notify its ULP about the successful 919 * establishment of the association with a Communication Up 920 * notification (see Section 10). 921 */ 922 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 923 0, asoc->c.sinit_num_ostreams, 924 asoc->c.sinit_max_instreams, 925 NULL, GFP_ATOMIC); 926 927 if (!ev) 928 goto nomem; 929 930 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 931 932 /* Sockets API Draft Section 5.3.1.6 933 * When a peer sends a Adaptation Layer Indication parameter , SCTP 934 * delivers this notification to inform the application that of the 935 * peers requested adaptation layer. 936 */ 937 if (asoc->peer.adaptation_ind) { 938 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 939 if (!ev) 940 goto nomem; 941 942 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 943 SCTP_ULPEVENT(ev)); 944 } 945 946 return SCTP_DISPOSITION_CONSUME; 947 nomem: 948 return SCTP_DISPOSITION_NOMEM; 949 } 950 951 /* Generate and sendout a heartbeat packet. */ 952 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 953 const struct sctp_association *asoc, 954 const sctp_subtype_t type, 955 void *arg, 956 sctp_cmd_seq_t *commands) 957 { 958 struct sctp_transport *transport = (struct sctp_transport *) arg; 959 struct sctp_chunk *reply; 960 961 /* Send a heartbeat to our peer. */ 962 reply = sctp_make_heartbeat(asoc, transport); 963 if (!reply) 964 return SCTP_DISPOSITION_NOMEM; 965 966 /* Set rto_pending indicating that an RTT measurement 967 * is started with this heartbeat chunk. 968 */ 969 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 970 SCTP_TRANSPORT(transport)); 971 972 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 973 return SCTP_DISPOSITION_CONSUME; 974 } 975 976 /* Generate a HEARTBEAT packet on the given transport. */ 977 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 978 const struct sctp_endpoint *ep, 979 const struct sctp_association *asoc, 980 const sctp_subtype_t type, 981 void *arg, 982 sctp_cmd_seq_t *commands) 983 { 984 struct sctp_transport *transport = (struct sctp_transport *) arg; 985 986 if (asoc->overall_error_count >= asoc->max_retrans) { 987 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 988 SCTP_ERROR(ETIMEDOUT)); 989 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 990 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 991 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 992 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 993 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 994 return SCTP_DISPOSITION_DELETE_TCB; 995 } 996 997 /* Section 3.3.5. 998 * The Sender-specific Heartbeat Info field should normally include 999 * information about the sender's current time when this HEARTBEAT 1000 * chunk is sent and the destination transport address to which this 1001 * HEARTBEAT is sent (see Section 8.3). 1002 */ 1003 1004 if (transport->param_flags & SPP_HB_ENABLE) { 1005 if (SCTP_DISPOSITION_NOMEM == 1006 sctp_sf_heartbeat(ep, asoc, type, arg, 1007 commands)) 1008 return SCTP_DISPOSITION_NOMEM; 1009 1010 /* Set transport error counter and association error counter 1011 * when sending heartbeat. 1012 */ 1013 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1014 SCTP_TRANSPORT(transport)); 1015 } 1016 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1017 SCTP_TRANSPORT(transport)); 1018 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1019 SCTP_TRANSPORT(transport)); 1020 1021 return SCTP_DISPOSITION_CONSUME; 1022 } 1023 1024 /* 1025 * Process an heartbeat request. 1026 * 1027 * Section: 8.3 Path Heartbeat 1028 * The receiver of the HEARTBEAT should immediately respond with a 1029 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1030 * from the received HEARTBEAT chunk. 1031 * 1032 * Verification Tag: 8.5 Verification Tag [Normal verification] 1033 * When receiving an SCTP packet, the endpoint MUST ensure that the 1034 * value in the Verification Tag field of the received SCTP packet 1035 * matches its own Tag. If the received Verification Tag value does not 1036 * match the receiver's own tag value, the receiver shall silently 1037 * discard the packet and shall not process it any further except for 1038 * those cases listed in Section 8.5.1 below. 1039 * 1040 * Inputs 1041 * (endpoint, asoc, chunk) 1042 * 1043 * Outputs 1044 * (asoc, reply_msg, msg_up, timers, counters) 1045 * 1046 * The return value is the disposition of the chunk. 1047 */ 1048 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1049 const struct sctp_endpoint *ep, 1050 const struct sctp_association *asoc, 1051 const sctp_subtype_t type, 1052 void *arg, 1053 sctp_cmd_seq_t *commands) 1054 { 1055 sctp_paramhdr_t *param_hdr; 1056 struct sctp_chunk *chunk = arg; 1057 struct sctp_chunk *reply; 1058 size_t paylen = 0; 1059 1060 if (!sctp_vtag_verify(chunk, asoc)) 1061 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1062 1063 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1064 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1065 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1066 commands); 1067 1068 /* 8.3 The receiver of the HEARTBEAT should immediately 1069 * respond with a HEARTBEAT ACK that contains the Heartbeat 1070 * Information field copied from the received HEARTBEAT chunk. 1071 */ 1072 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1073 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr; 1074 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1075 1076 if (ntohs(param_hdr->length) > paylen) 1077 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1078 param_hdr, commands); 1079 1080 if (!pskb_pull(chunk->skb, paylen)) 1081 goto nomem; 1082 1083 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1084 if (!reply) 1085 goto nomem; 1086 1087 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1088 return SCTP_DISPOSITION_CONSUME; 1089 1090 nomem: 1091 return SCTP_DISPOSITION_NOMEM; 1092 } 1093 1094 /* 1095 * Process the returning HEARTBEAT ACK. 1096 * 1097 * Section: 8.3 Path Heartbeat 1098 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1099 * should clear the error counter of the destination transport 1100 * address to which the HEARTBEAT was sent, and mark the destination 1101 * transport address as active if it is not so marked. The endpoint may 1102 * optionally report to the upper layer when an inactive destination 1103 * address is marked as active due to the reception of the latest 1104 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1105 * clear the association overall error count as well (as defined 1106 * in section 8.1). 1107 * 1108 * The receiver of the HEARTBEAT ACK should also perform an RTT 1109 * measurement for that destination transport address using the time 1110 * value carried in the HEARTBEAT ACK chunk. 1111 * 1112 * Verification Tag: 8.5 Verification Tag [Normal verification] 1113 * 1114 * Inputs 1115 * (endpoint, asoc, chunk) 1116 * 1117 * Outputs 1118 * (asoc, reply_msg, msg_up, timers, counters) 1119 * 1120 * The return value is the disposition of the chunk. 1121 */ 1122 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1123 const struct sctp_endpoint *ep, 1124 const struct sctp_association *asoc, 1125 const sctp_subtype_t type, 1126 void *arg, 1127 sctp_cmd_seq_t *commands) 1128 { 1129 struct sctp_chunk *chunk = arg; 1130 union sctp_addr from_addr; 1131 struct sctp_transport *link; 1132 sctp_sender_hb_info_t *hbinfo; 1133 unsigned long max_interval; 1134 1135 if (!sctp_vtag_verify(chunk, asoc)) 1136 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1137 1138 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1139 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1140 sizeof(sctp_sender_hb_info_t))) 1141 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1142 commands); 1143 1144 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1145 /* Make sure that the length of the parameter is what we expect */ 1146 if (ntohs(hbinfo->param_hdr.length) != 1147 sizeof(sctp_sender_hb_info_t)) { 1148 return SCTP_DISPOSITION_DISCARD; 1149 } 1150 1151 from_addr = hbinfo->daddr; 1152 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1153 1154 /* This should never happen, but lets log it if so. */ 1155 if (unlikely(!link)) { 1156 if (from_addr.sa.sa_family == AF_INET6) { 1157 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1158 __func__, 1159 asoc, 1160 &from_addr.v6.sin6_addr); 1161 } else { 1162 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1163 __func__, 1164 asoc, 1165 &from_addr.v4.sin_addr.s_addr); 1166 } 1167 return SCTP_DISPOSITION_DISCARD; 1168 } 1169 1170 /* Validate the 64-bit random nonce. */ 1171 if (hbinfo->hb_nonce != link->hb_nonce) 1172 return SCTP_DISPOSITION_DISCARD; 1173 1174 max_interval = link->hbinterval + link->rto; 1175 1176 /* Check if the timestamp looks valid. */ 1177 if (time_after(hbinfo->sent_at, jiffies) || 1178 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1179 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1180 "for transport:%p\n", __func__, link); 1181 1182 return SCTP_DISPOSITION_DISCARD; 1183 } 1184 1185 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1186 * the HEARTBEAT should clear the error counter of the 1187 * destination transport address to which the HEARTBEAT was 1188 * sent and mark the destination transport address as active if 1189 * it is not so marked. 1190 */ 1191 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1192 1193 return SCTP_DISPOSITION_CONSUME; 1194 } 1195 1196 /* Helper function to send out an abort for the restart 1197 * condition. 1198 */ 1199 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1200 struct sctp_chunk *init, 1201 sctp_cmd_seq_t *commands) 1202 { 1203 int len; 1204 struct sctp_packet *pkt; 1205 union sctp_addr_param *addrparm; 1206 struct sctp_errhdr *errhdr; 1207 struct sctp_endpoint *ep; 1208 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1209 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1210 1211 /* Build the error on the stack. We are way to malloc crazy 1212 * throughout the code today. 1213 */ 1214 errhdr = (struct sctp_errhdr *)buffer; 1215 addrparm = (union sctp_addr_param *)errhdr->variable; 1216 1217 /* Copy into a parm format. */ 1218 len = af->to_addr_param(ssa, addrparm); 1219 len += sizeof(sctp_errhdr_t); 1220 1221 errhdr->cause = SCTP_ERROR_RESTART; 1222 errhdr->length = htons(len); 1223 1224 /* Assign to the control socket. */ 1225 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1226 1227 /* Association is NULL since this may be a restart attack and we 1228 * want to send back the attacker's vtag. 1229 */ 1230 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1231 1232 if (!pkt) 1233 goto out; 1234 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1235 1236 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1237 1238 /* Discard the rest of the inbound packet. */ 1239 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1240 1241 out: 1242 /* Even if there is no memory, treat as a failure so 1243 * the packet will get dropped. 1244 */ 1245 return 0; 1246 } 1247 1248 static bool list_has_sctp_addr(const struct list_head *list, 1249 union sctp_addr *ipaddr) 1250 { 1251 struct sctp_transport *addr; 1252 1253 list_for_each_entry(addr, list, transports) { 1254 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1255 return true; 1256 } 1257 1258 return false; 1259 } 1260 /* A restart is occurring, check to make sure no new addresses 1261 * are being added as we may be under a takeover attack. 1262 */ 1263 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1264 const struct sctp_association *asoc, 1265 struct sctp_chunk *init, 1266 sctp_cmd_seq_t *commands) 1267 { 1268 struct net *net = sock_net(new_asoc->base.sk); 1269 struct sctp_transport *new_addr; 1270 int ret = 1; 1271 1272 /* Implementor's Guide - Section 5.2.2 1273 * ... 1274 * Before responding the endpoint MUST check to see if the 1275 * unexpected INIT adds new addresses to the association. If new 1276 * addresses are added to the association, the endpoint MUST respond 1277 * with an ABORT.. 1278 */ 1279 1280 /* Search through all current addresses and make sure 1281 * we aren't adding any new ones. 1282 */ 1283 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1284 transports) { 1285 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1286 &new_addr->ipaddr)) { 1287 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1288 commands); 1289 ret = 0; 1290 break; 1291 } 1292 } 1293 1294 /* Return success if all addresses were found. */ 1295 return ret; 1296 } 1297 1298 /* Populate the verification/tie tags based on overlapping INIT 1299 * scenario. 1300 * 1301 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1302 */ 1303 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1304 const struct sctp_association *asoc) 1305 { 1306 switch (asoc->state) { 1307 1308 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1309 1310 case SCTP_STATE_COOKIE_WAIT: 1311 new_asoc->c.my_vtag = asoc->c.my_vtag; 1312 new_asoc->c.my_ttag = asoc->c.my_vtag; 1313 new_asoc->c.peer_ttag = 0; 1314 break; 1315 1316 case SCTP_STATE_COOKIE_ECHOED: 1317 new_asoc->c.my_vtag = asoc->c.my_vtag; 1318 new_asoc->c.my_ttag = asoc->c.my_vtag; 1319 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1320 break; 1321 1322 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1323 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1324 */ 1325 default: 1326 new_asoc->c.my_ttag = asoc->c.my_vtag; 1327 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1328 break; 1329 } 1330 1331 /* Other parameters for the endpoint SHOULD be copied from the 1332 * existing parameters of the association (e.g. number of 1333 * outbound streams) into the INIT ACK and cookie. 1334 */ 1335 new_asoc->rwnd = asoc->rwnd; 1336 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1337 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1338 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1339 } 1340 1341 /* 1342 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1343 * handling action. 1344 * 1345 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1346 * 1347 * Returns value representing action to be taken. These action values 1348 * correspond to Action/Description values in RFC 2960, Table 2. 1349 */ 1350 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1351 const struct sctp_association *asoc) 1352 { 1353 /* In this case, the peer may have restarted. */ 1354 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1355 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1356 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1357 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1358 return 'A'; 1359 1360 /* Collision case B. */ 1361 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1362 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1363 (0 == asoc->c.peer_vtag))) { 1364 return 'B'; 1365 } 1366 1367 /* Collision case D. */ 1368 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1369 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1370 return 'D'; 1371 1372 /* Collision case C. */ 1373 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1374 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1375 (0 == new_asoc->c.my_ttag) && 1376 (0 == new_asoc->c.peer_ttag)) 1377 return 'C'; 1378 1379 /* No match to any of the special cases; discard this packet. */ 1380 return 'E'; 1381 } 1382 1383 /* Common helper routine for both duplicate and simulataneous INIT 1384 * chunk handling. 1385 */ 1386 static sctp_disposition_t sctp_sf_do_unexpected_init( 1387 struct net *net, 1388 const struct sctp_endpoint *ep, 1389 const struct sctp_association *asoc, 1390 const sctp_subtype_t type, 1391 void *arg, sctp_cmd_seq_t *commands) 1392 { 1393 sctp_disposition_t retval; 1394 struct sctp_chunk *chunk = arg; 1395 struct sctp_chunk *repl; 1396 struct sctp_association *new_asoc; 1397 struct sctp_chunk *err_chunk; 1398 struct sctp_packet *packet; 1399 sctp_unrecognized_param_t *unk_param; 1400 int len; 1401 1402 /* 6.10 Bundling 1403 * An endpoint MUST NOT bundle INIT, INIT ACK or 1404 * SHUTDOWN COMPLETE with any other chunks. 1405 * 1406 * IG Section 2.11.2 1407 * Furthermore, we require that the receiver of an INIT chunk MUST 1408 * enforce these rules by silently discarding an arriving packet 1409 * with an INIT chunk that is bundled with other chunks. 1410 */ 1411 if (!chunk->singleton) 1412 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1413 1414 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1415 * Tag. 1416 */ 1417 if (chunk->sctp_hdr->vtag != 0) 1418 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1419 1420 /* Make sure that the INIT chunk has a valid length. 1421 * In this case, we generate a protocol violation since we have 1422 * an association established. 1423 */ 1424 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1425 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1426 commands); 1427 /* Grab the INIT header. */ 1428 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1429 1430 /* Tag the variable length parameters. */ 1431 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1432 1433 /* Verify the INIT chunk before processing it. */ 1434 err_chunk = NULL; 1435 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1436 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1437 &err_chunk)) { 1438 /* This chunk contains fatal error. It is to be discarded. 1439 * Send an ABORT, with causes if there is any. 1440 */ 1441 if (err_chunk) { 1442 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1443 (__u8 *)(err_chunk->chunk_hdr) + 1444 sizeof(sctp_chunkhdr_t), 1445 ntohs(err_chunk->chunk_hdr->length) - 1446 sizeof(sctp_chunkhdr_t)); 1447 1448 if (packet) { 1449 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1450 SCTP_PACKET(packet)); 1451 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1452 retval = SCTP_DISPOSITION_CONSUME; 1453 } else { 1454 retval = SCTP_DISPOSITION_NOMEM; 1455 } 1456 goto cleanup; 1457 } else { 1458 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1459 commands); 1460 } 1461 } 1462 1463 /* 1464 * Other parameters for the endpoint SHOULD be copied from the 1465 * existing parameters of the association (e.g. number of 1466 * outbound streams) into the INIT ACK and cookie. 1467 * FIXME: We are copying parameters from the endpoint not the 1468 * association. 1469 */ 1470 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1471 if (!new_asoc) 1472 goto nomem; 1473 1474 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1475 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1476 goto nomem; 1477 1478 /* In the outbound INIT ACK the endpoint MUST copy its current 1479 * Verification Tag and Peers Verification tag into a reserved 1480 * place (local tie-tag and per tie-tag) within the state cookie. 1481 */ 1482 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1483 (sctp_init_chunk_t *)chunk->chunk_hdr, 1484 GFP_ATOMIC)) 1485 goto nomem; 1486 1487 /* Make sure no new addresses are being added during the 1488 * restart. Do not do this check for COOKIE-WAIT state, 1489 * since there are no peer addresses to check against. 1490 * Upon return an ABORT will have been sent if needed. 1491 */ 1492 if (!sctp_state(asoc, COOKIE_WAIT)) { 1493 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1494 commands)) { 1495 retval = SCTP_DISPOSITION_CONSUME; 1496 goto nomem_retval; 1497 } 1498 } 1499 1500 sctp_tietags_populate(new_asoc, asoc); 1501 1502 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1503 1504 /* If there are errors need to be reported for unknown parameters, 1505 * make sure to reserve enough room in the INIT ACK for them. 1506 */ 1507 len = 0; 1508 if (err_chunk) { 1509 len = ntohs(err_chunk->chunk_hdr->length) - 1510 sizeof(sctp_chunkhdr_t); 1511 } 1512 1513 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1514 if (!repl) 1515 goto nomem; 1516 1517 /* If there are errors need to be reported for unknown parameters, 1518 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1519 * parameter. 1520 */ 1521 if (err_chunk) { 1522 /* Get the "Unrecognized parameter" parameter(s) out of the 1523 * ERROR chunk generated by sctp_verify_init(). Since the 1524 * error cause code for "unknown parameter" and the 1525 * "Unrecognized parameter" type is the same, we can 1526 * construct the parameters in INIT ACK by copying the 1527 * ERROR causes over. 1528 */ 1529 unk_param = (sctp_unrecognized_param_t *) 1530 ((__u8 *)(err_chunk->chunk_hdr) + 1531 sizeof(sctp_chunkhdr_t)); 1532 /* Replace the cause code with the "Unrecognized parameter" 1533 * parameter type. 1534 */ 1535 sctp_addto_chunk(repl, len, unk_param); 1536 } 1537 1538 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1539 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1540 1541 /* 1542 * Note: After sending out INIT ACK with the State Cookie parameter, 1543 * "Z" MUST NOT allocate any resources for this new association. 1544 * Otherwise, "Z" will be vulnerable to resource attacks. 1545 */ 1546 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1547 retval = SCTP_DISPOSITION_CONSUME; 1548 1549 return retval; 1550 1551 nomem: 1552 retval = SCTP_DISPOSITION_NOMEM; 1553 nomem_retval: 1554 if (new_asoc) 1555 sctp_association_free(new_asoc); 1556 cleanup: 1557 if (err_chunk) 1558 sctp_chunk_free(err_chunk); 1559 return retval; 1560 } 1561 1562 /* 1563 * Handle simultaneous INIT. 1564 * This means we started an INIT and then we got an INIT request from 1565 * our peer. 1566 * 1567 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1568 * This usually indicates an initialization collision, i.e., each 1569 * endpoint is attempting, at about the same time, to establish an 1570 * association with the other endpoint. 1571 * 1572 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1573 * endpoint MUST respond with an INIT ACK using the same parameters it 1574 * sent in its original INIT chunk (including its Verification Tag, 1575 * unchanged). These original parameters are combined with those from the 1576 * newly received INIT chunk. The endpoint shall also generate a State 1577 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1578 * INIT to calculate the State Cookie. 1579 * 1580 * After that, the endpoint MUST NOT change its state, the T1-init 1581 * timer shall be left running and the corresponding TCB MUST NOT be 1582 * destroyed. The normal procedures for handling State Cookies when 1583 * a TCB exists will resolve the duplicate INITs to a single association. 1584 * 1585 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1586 * its Tie-Tags with the Tag information of itself and its peer (see 1587 * section 5.2.2 for a description of the Tie-Tags). 1588 * 1589 * Verification Tag: Not explicit, but an INIT can not have a valid 1590 * verification tag, so we skip the check. 1591 * 1592 * Inputs 1593 * (endpoint, asoc, chunk) 1594 * 1595 * Outputs 1596 * (asoc, reply_msg, msg_up, timers, counters) 1597 * 1598 * The return value is the disposition of the chunk. 1599 */ 1600 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1601 const struct sctp_endpoint *ep, 1602 const struct sctp_association *asoc, 1603 const sctp_subtype_t type, 1604 void *arg, 1605 sctp_cmd_seq_t *commands) 1606 { 1607 /* Call helper to do the real work for both simulataneous and 1608 * duplicate INIT chunk handling. 1609 */ 1610 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1611 } 1612 1613 /* 1614 * Handle duplicated INIT messages. These are usually delayed 1615 * restransmissions. 1616 * 1617 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1618 * COOKIE-ECHOED and COOKIE-WAIT 1619 * 1620 * Unless otherwise stated, upon reception of an unexpected INIT for 1621 * this association, the endpoint shall generate an INIT ACK with a 1622 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1623 * current Verification Tag and peer's Verification Tag into a reserved 1624 * place within the state cookie. We shall refer to these locations as 1625 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1626 * containing this INIT ACK MUST carry a Verification Tag value equal to 1627 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1628 * MUST contain a new Initiation Tag (randomly generated see Section 1629 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1630 * existing parameters of the association (e.g. number of outbound 1631 * streams) into the INIT ACK and cookie. 1632 * 1633 * After sending out the INIT ACK, the endpoint shall take no further 1634 * actions, i.e., the existing association, including its current state, 1635 * and the corresponding TCB MUST NOT be changed. 1636 * 1637 * Note: Only when a TCB exists and the association is not in a COOKIE- 1638 * WAIT state are the Tie-Tags populated. For a normal association INIT 1639 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1640 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1641 * State Cookie are populated as specified in section 5.2.1. 1642 * 1643 * Verification Tag: Not specified, but an INIT has no way of knowing 1644 * what the verification tag could be, so we ignore it. 1645 * 1646 * Inputs 1647 * (endpoint, asoc, chunk) 1648 * 1649 * Outputs 1650 * (asoc, reply_msg, msg_up, timers, counters) 1651 * 1652 * The return value is the disposition of the chunk. 1653 */ 1654 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1655 const struct sctp_endpoint *ep, 1656 const struct sctp_association *asoc, 1657 const sctp_subtype_t type, 1658 void *arg, 1659 sctp_cmd_seq_t *commands) 1660 { 1661 /* Call helper to do the real work for both simulataneous and 1662 * duplicate INIT chunk handling. 1663 */ 1664 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1665 } 1666 1667 1668 /* 1669 * Unexpected INIT-ACK handler. 1670 * 1671 * Section 5.2.3 1672 * If an INIT ACK received by an endpoint in any state other than the 1673 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1674 * An unexpected INIT ACK usually indicates the processing of an old or 1675 * duplicated INIT chunk. 1676 */ 1677 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1678 const struct sctp_endpoint *ep, 1679 const struct sctp_association *asoc, 1680 const sctp_subtype_t type, 1681 void *arg, sctp_cmd_seq_t *commands) 1682 { 1683 /* Per the above section, we'll discard the chunk if we have an 1684 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1685 */ 1686 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1687 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1688 else 1689 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1690 } 1691 1692 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1693 * 1694 * Section 5.2.4 1695 * A) In this case, the peer may have restarted. 1696 */ 1697 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1698 const struct sctp_endpoint *ep, 1699 const struct sctp_association *asoc, 1700 struct sctp_chunk *chunk, 1701 sctp_cmd_seq_t *commands, 1702 struct sctp_association *new_asoc) 1703 { 1704 sctp_init_chunk_t *peer_init; 1705 struct sctp_ulpevent *ev; 1706 struct sctp_chunk *repl; 1707 struct sctp_chunk *err; 1708 sctp_disposition_t disposition; 1709 1710 /* new_asoc is a brand-new association, so these are not yet 1711 * side effects--it is safe to run them here. 1712 */ 1713 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1714 1715 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1716 GFP_ATOMIC)) 1717 goto nomem; 1718 1719 /* Make sure no new addresses are being added during the 1720 * restart. Though this is a pretty complicated attack 1721 * since you'd have to get inside the cookie. 1722 */ 1723 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1724 return SCTP_DISPOSITION_CONSUME; 1725 } 1726 1727 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1728 * the peer has restarted (Action A), it MUST NOT setup a new 1729 * association but instead resend the SHUTDOWN ACK and send an ERROR 1730 * chunk with a "Cookie Received while Shutting Down" error cause to 1731 * its peer. 1732 */ 1733 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1734 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1735 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1736 chunk, commands); 1737 if (SCTP_DISPOSITION_NOMEM == disposition) 1738 goto nomem; 1739 1740 err = sctp_make_op_error(asoc, chunk, 1741 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1742 NULL, 0, 0); 1743 if (err) 1744 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1745 SCTP_CHUNK(err)); 1746 1747 return SCTP_DISPOSITION_CONSUME; 1748 } 1749 1750 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1751 * data. Consider the optional choice of resending of this data. 1752 */ 1753 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1754 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1755 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1756 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1757 1758 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1759 * and ASCONF-ACK cache. 1760 */ 1761 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1762 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1763 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1764 1765 repl = sctp_make_cookie_ack(new_asoc, chunk); 1766 if (!repl) 1767 goto nomem; 1768 1769 /* Report association restart to upper layer. */ 1770 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1771 new_asoc->c.sinit_num_ostreams, 1772 new_asoc->c.sinit_max_instreams, 1773 NULL, GFP_ATOMIC); 1774 if (!ev) 1775 goto nomem_ev; 1776 1777 /* Update the content of current association. */ 1778 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1779 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1780 if (sctp_state(asoc, SHUTDOWN_PENDING) && 1781 (sctp_sstate(asoc->base.sk, CLOSING) || 1782 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1783 /* if were currently in SHUTDOWN_PENDING, but the socket 1784 * has been closed by user, don't transition to ESTABLISHED. 1785 * Instead trigger SHUTDOWN bundled with COOKIE_ACK. 1786 */ 1787 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1788 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1789 SCTP_ST_CHUNK(0), NULL, 1790 commands); 1791 } else { 1792 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1793 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1794 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1795 } 1796 return SCTP_DISPOSITION_CONSUME; 1797 1798 nomem_ev: 1799 sctp_chunk_free(repl); 1800 nomem: 1801 return SCTP_DISPOSITION_NOMEM; 1802 } 1803 1804 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1805 * 1806 * Section 5.2.4 1807 * B) In this case, both sides may be attempting to start an association 1808 * at about the same time but the peer endpoint started its INIT 1809 * after responding to the local endpoint's INIT 1810 */ 1811 /* This case represents an initialization collision. */ 1812 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1813 const struct sctp_endpoint *ep, 1814 const struct sctp_association *asoc, 1815 struct sctp_chunk *chunk, 1816 sctp_cmd_seq_t *commands, 1817 struct sctp_association *new_asoc) 1818 { 1819 sctp_init_chunk_t *peer_init; 1820 struct sctp_chunk *repl; 1821 1822 /* new_asoc is a brand-new association, so these are not yet 1823 * side effects--it is safe to run them here. 1824 */ 1825 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1826 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1827 GFP_ATOMIC)) 1828 goto nomem; 1829 1830 /* Update the content of current association. */ 1831 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1832 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1833 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1834 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1835 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1836 1837 repl = sctp_make_cookie_ack(new_asoc, chunk); 1838 if (!repl) 1839 goto nomem; 1840 1841 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1842 1843 /* RFC 2960 5.1 Normal Establishment of an Association 1844 * 1845 * D) IMPLEMENTATION NOTE: An implementation may choose to 1846 * send the Communication Up notification to the SCTP user 1847 * upon reception of a valid COOKIE ECHO chunk. 1848 * 1849 * Sadly, this needs to be implemented as a side-effect, because 1850 * we are not guaranteed to have set the association id of the real 1851 * association and so these notifications need to be delayed until 1852 * the association id is allocated. 1853 */ 1854 1855 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1856 1857 /* Sockets API Draft Section 5.3.1.6 1858 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1859 * delivers this notification to inform the application that of the 1860 * peers requested adaptation layer. 1861 * 1862 * This also needs to be done as a side effect for the same reason as 1863 * above. 1864 */ 1865 if (asoc->peer.adaptation_ind) 1866 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1867 1868 return SCTP_DISPOSITION_CONSUME; 1869 1870 nomem: 1871 return SCTP_DISPOSITION_NOMEM; 1872 } 1873 1874 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1875 * 1876 * Section 5.2.4 1877 * C) In this case, the local endpoint's cookie has arrived late. 1878 * Before it arrived, the local endpoint sent an INIT and received an 1879 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1880 * but a new tag of its own. 1881 */ 1882 /* This case represents an initialization collision. */ 1883 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1884 const struct sctp_endpoint *ep, 1885 const struct sctp_association *asoc, 1886 struct sctp_chunk *chunk, 1887 sctp_cmd_seq_t *commands, 1888 struct sctp_association *new_asoc) 1889 { 1890 /* The cookie should be silently discarded. 1891 * The endpoint SHOULD NOT change states and should leave 1892 * any timers running. 1893 */ 1894 return SCTP_DISPOSITION_DISCARD; 1895 } 1896 1897 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1898 * 1899 * Section 5.2.4 1900 * 1901 * D) When both local and remote tags match the endpoint should always 1902 * enter the ESTABLISHED state, if it has not already done so. 1903 */ 1904 /* This case represents an initialization collision. */ 1905 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1906 const struct sctp_endpoint *ep, 1907 const struct sctp_association *asoc, 1908 struct sctp_chunk *chunk, 1909 sctp_cmd_seq_t *commands, 1910 struct sctp_association *new_asoc) 1911 { 1912 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1913 struct sctp_chunk *repl; 1914 1915 /* Clarification from Implementor's Guide: 1916 * D) When both local and remote tags match the endpoint should 1917 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1918 * It should stop any cookie timer that may be running and send 1919 * a COOKIE ACK. 1920 */ 1921 1922 /* Don't accidentally move back into established state. */ 1923 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1924 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1925 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1926 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1927 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1928 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1929 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1930 SCTP_NULL()); 1931 1932 /* RFC 2960 5.1 Normal Establishment of an Association 1933 * 1934 * D) IMPLEMENTATION NOTE: An implementation may choose 1935 * to send the Communication Up notification to the 1936 * SCTP user upon reception of a valid COOKIE 1937 * ECHO chunk. 1938 */ 1939 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1940 SCTP_COMM_UP, 0, 1941 asoc->c.sinit_num_ostreams, 1942 asoc->c.sinit_max_instreams, 1943 NULL, GFP_ATOMIC); 1944 if (!ev) 1945 goto nomem; 1946 1947 /* Sockets API Draft Section 5.3.1.6 1948 * When a peer sends a Adaptation Layer Indication parameter, 1949 * SCTP delivers this notification to inform the application 1950 * that of the peers requested adaptation layer. 1951 */ 1952 if (asoc->peer.adaptation_ind) { 1953 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1954 GFP_ATOMIC); 1955 if (!ai_ev) 1956 goto nomem; 1957 1958 } 1959 } 1960 1961 repl = sctp_make_cookie_ack(new_asoc, chunk); 1962 if (!repl) 1963 goto nomem; 1964 1965 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1966 1967 if (ev) 1968 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1969 SCTP_ULPEVENT(ev)); 1970 if (ai_ev) 1971 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1972 SCTP_ULPEVENT(ai_ev)); 1973 1974 return SCTP_DISPOSITION_CONSUME; 1975 1976 nomem: 1977 if (ai_ev) 1978 sctp_ulpevent_free(ai_ev); 1979 if (ev) 1980 sctp_ulpevent_free(ev); 1981 return SCTP_DISPOSITION_NOMEM; 1982 } 1983 1984 /* 1985 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1986 * chunk was retransmitted and then delayed in the network. 1987 * 1988 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1989 * 1990 * Verification Tag: None. Do cookie validation. 1991 * 1992 * Inputs 1993 * (endpoint, asoc, chunk) 1994 * 1995 * Outputs 1996 * (asoc, reply_msg, msg_up, timers, counters) 1997 * 1998 * The return value is the disposition of the chunk. 1999 */ 2000 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 2001 const struct sctp_endpoint *ep, 2002 const struct sctp_association *asoc, 2003 const sctp_subtype_t type, 2004 void *arg, 2005 sctp_cmd_seq_t *commands) 2006 { 2007 sctp_disposition_t retval; 2008 struct sctp_chunk *chunk = arg; 2009 struct sctp_association *new_asoc; 2010 int error = 0; 2011 char action; 2012 struct sctp_chunk *err_chk_p; 2013 2014 /* Make sure that the chunk has a valid length from the protocol 2015 * perspective. In this case check to make sure we have at least 2016 * enough for the chunk header. Cookie length verification is 2017 * done later. 2018 */ 2019 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2020 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2021 commands); 2022 2023 /* "Decode" the chunk. We have no optional parameters so we 2024 * are in good shape. 2025 */ 2026 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2027 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2028 sizeof(sctp_chunkhdr_t))) 2029 goto nomem; 2030 2031 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2032 * of a duplicate COOKIE ECHO match the Verification Tags of the 2033 * current association, consider the State Cookie valid even if 2034 * the lifespan is exceeded. 2035 */ 2036 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2037 &err_chk_p); 2038 2039 /* FIXME: 2040 * If the re-build failed, what is the proper error path 2041 * from here? 2042 * 2043 * [We should abort the association. --piggy] 2044 */ 2045 if (!new_asoc) { 2046 /* FIXME: Several errors are possible. A bad cookie should 2047 * be silently discarded, but think about logging it too. 2048 */ 2049 switch (error) { 2050 case -SCTP_IERROR_NOMEM: 2051 goto nomem; 2052 2053 case -SCTP_IERROR_STALE_COOKIE: 2054 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2055 err_chk_p); 2056 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2057 case -SCTP_IERROR_BAD_SIG: 2058 default: 2059 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2060 } 2061 } 2062 2063 /* Compare the tie_tag in cookie with the verification tag of 2064 * current association. 2065 */ 2066 action = sctp_tietags_compare(new_asoc, asoc); 2067 2068 switch (action) { 2069 case 'A': /* Association restart. */ 2070 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2071 new_asoc); 2072 break; 2073 2074 case 'B': /* Collision case B. */ 2075 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2076 new_asoc); 2077 break; 2078 2079 case 'C': /* Collision case C. */ 2080 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2081 new_asoc); 2082 break; 2083 2084 case 'D': /* Collision case D. */ 2085 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2086 new_asoc); 2087 break; 2088 2089 default: /* Discard packet for all others. */ 2090 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2091 break; 2092 } 2093 2094 /* Delete the tempory new association. */ 2095 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2096 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2097 2098 /* Restore association pointer to provide SCTP command interpeter 2099 * with a valid context in case it needs to manipulate 2100 * the queues */ 2101 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2102 SCTP_ASOC((struct sctp_association *)asoc)); 2103 2104 return retval; 2105 2106 nomem: 2107 return SCTP_DISPOSITION_NOMEM; 2108 } 2109 2110 /* 2111 * Process an ABORT. (SHUTDOWN-PENDING state) 2112 * 2113 * See sctp_sf_do_9_1_abort(). 2114 */ 2115 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2116 struct net *net, 2117 const struct sctp_endpoint *ep, 2118 const struct sctp_association *asoc, 2119 const sctp_subtype_t type, 2120 void *arg, 2121 sctp_cmd_seq_t *commands) 2122 { 2123 struct sctp_chunk *chunk = arg; 2124 2125 if (!sctp_vtag_verify_either(chunk, asoc)) 2126 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2127 2128 /* Make sure that the ABORT chunk has a valid length. 2129 * Since this is an ABORT chunk, we have to discard it 2130 * because of the following text: 2131 * RFC 2960, Section 3.3.7 2132 * If an endpoint receives an ABORT with a format error or for an 2133 * association that doesn't exist, it MUST silently discard it. 2134 * Because the length is "invalid", we can't really discard just 2135 * as we do not know its true length. So, to be safe, discard the 2136 * packet. 2137 */ 2138 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2139 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2140 2141 /* ADD-IP: Special case for ABORT chunks 2142 * F4) One special consideration is that ABORT Chunks arriving 2143 * destined to the IP address being deleted MUST be 2144 * ignored (see Section 5.3.1 for further details). 2145 */ 2146 if (SCTP_ADDR_DEL == 2147 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2148 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2149 2150 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2151 } 2152 2153 /* 2154 * Process an ABORT. (SHUTDOWN-SENT state) 2155 * 2156 * See sctp_sf_do_9_1_abort(). 2157 */ 2158 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2159 const struct sctp_endpoint *ep, 2160 const struct sctp_association *asoc, 2161 const sctp_subtype_t type, 2162 void *arg, 2163 sctp_cmd_seq_t *commands) 2164 { 2165 struct sctp_chunk *chunk = arg; 2166 2167 if (!sctp_vtag_verify_either(chunk, asoc)) 2168 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2169 2170 /* Make sure that the ABORT chunk has a valid length. 2171 * Since this is an ABORT chunk, we have to discard it 2172 * because of the following text: 2173 * RFC 2960, Section 3.3.7 2174 * If an endpoint receives an ABORT with a format error or for an 2175 * association that doesn't exist, it MUST silently discard it. 2176 * Because the length is "invalid", we can't really discard just 2177 * as we do not know its true length. So, to be safe, discard the 2178 * packet. 2179 */ 2180 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2181 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2182 2183 /* ADD-IP: Special case for ABORT chunks 2184 * F4) One special consideration is that ABORT Chunks arriving 2185 * destined to the IP address being deleted MUST be 2186 * ignored (see Section 5.3.1 for further details). 2187 */ 2188 if (SCTP_ADDR_DEL == 2189 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2190 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2191 2192 /* Stop the T2-shutdown timer. */ 2193 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2194 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2195 2196 /* Stop the T5-shutdown guard timer. */ 2197 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2198 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2199 2200 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2201 } 2202 2203 /* 2204 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2205 * 2206 * See sctp_sf_do_9_1_abort(). 2207 */ 2208 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2209 struct net *net, 2210 const struct sctp_endpoint *ep, 2211 const struct sctp_association *asoc, 2212 const sctp_subtype_t type, 2213 void *arg, 2214 sctp_cmd_seq_t *commands) 2215 { 2216 /* The same T2 timer, so we should be able to use 2217 * common function with the SHUTDOWN-SENT state. 2218 */ 2219 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2220 } 2221 2222 /* 2223 * Handle an Error received in COOKIE_ECHOED state. 2224 * 2225 * Only handle the error type of stale COOKIE Error, the other errors will 2226 * be ignored. 2227 * 2228 * Inputs 2229 * (endpoint, asoc, chunk) 2230 * 2231 * Outputs 2232 * (asoc, reply_msg, msg_up, timers, counters) 2233 * 2234 * The return value is the disposition of the chunk. 2235 */ 2236 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2237 const struct sctp_endpoint *ep, 2238 const struct sctp_association *asoc, 2239 const sctp_subtype_t type, 2240 void *arg, 2241 sctp_cmd_seq_t *commands) 2242 { 2243 struct sctp_chunk *chunk = arg; 2244 sctp_errhdr_t *err; 2245 2246 if (!sctp_vtag_verify(chunk, asoc)) 2247 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2248 2249 /* Make sure that the ERROR chunk has a valid length. 2250 * The parameter walking depends on this as well. 2251 */ 2252 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2253 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2254 commands); 2255 2256 /* Process the error here */ 2257 /* FUTURE FIXME: When PR-SCTP related and other optional 2258 * parms are emitted, this will have to change to handle multiple 2259 * errors. 2260 */ 2261 sctp_walk_errors(err, chunk->chunk_hdr) { 2262 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2263 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2264 arg, commands); 2265 } 2266 2267 /* It is possible to have malformed error causes, and that 2268 * will cause us to end the walk early. However, since 2269 * we are discarding the packet, there should be no adverse 2270 * affects. 2271 */ 2272 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2273 } 2274 2275 /* 2276 * Handle a Stale COOKIE Error 2277 * 2278 * Section: 5.2.6 Handle Stale COOKIE Error 2279 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2280 * one of the following three alternatives. 2281 * ... 2282 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2283 * Preservative parameter requesting an extension to the lifetime of 2284 * the State Cookie. When calculating the time extension, an 2285 * implementation SHOULD use the RTT information measured based on the 2286 * previous COOKIE ECHO / ERROR exchange, and should add no more 2287 * than 1 second beyond the measured RTT, due to long State Cookie 2288 * lifetimes making the endpoint more subject to a replay attack. 2289 * 2290 * Verification Tag: Not explicit, but safe to ignore. 2291 * 2292 * Inputs 2293 * (endpoint, asoc, chunk) 2294 * 2295 * Outputs 2296 * (asoc, reply_msg, msg_up, timers, counters) 2297 * 2298 * The return value is the disposition of the chunk. 2299 */ 2300 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2301 const struct sctp_endpoint *ep, 2302 const struct sctp_association *asoc, 2303 const sctp_subtype_t type, 2304 void *arg, 2305 sctp_cmd_seq_t *commands) 2306 { 2307 struct sctp_chunk *chunk = arg; 2308 u32 stale; 2309 sctp_cookie_preserve_param_t bht; 2310 sctp_errhdr_t *err; 2311 struct sctp_chunk *reply; 2312 struct sctp_bind_addr *bp; 2313 int attempts = asoc->init_err_counter + 1; 2314 2315 if (attempts > asoc->max_init_attempts) { 2316 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2317 SCTP_ERROR(ETIMEDOUT)); 2318 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2319 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2320 return SCTP_DISPOSITION_DELETE_TCB; 2321 } 2322 2323 err = (sctp_errhdr_t *)(chunk->skb->data); 2324 2325 /* When calculating the time extension, an implementation 2326 * SHOULD use the RTT information measured based on the 2327 * previous COOKIE ECHO / ERROR exchange, and should add no 2328 * more than 1 second beyond the measured RTT, due to long 2329 * State Cookie lifetimes making the endpoint more subject to 2330 * a replay attack. 2331 * Measure of Staleness's unit is usec. (1/1000000 sec) 2332 * Suggested Cookie Life-span Increment's unit is msec. 2333 * (1/1000 sec) 2334 * In general, if you use the suggested cookie life, the value 2335 * found in the field of measure of staleness should be doubled 2336 * to give ample time to retransmit the new cookie and thus 2337 * yield a higher probability of success on the reattempt. 2338 */ 2339 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2340 stale = (stale * 2) / 1000; 2341 2342 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2343 bht.param_hdr.length = htons(sizeof(bht)); 2344 bht.lifespan_increment = htonl(stale); 2345 2346 /* Build that new INIT chunk. */ 2347 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2348 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2349 if (!reply) 2350 goto nomem; 2351 2352 sctp_addto_chunk(reply, sizeof(bht), &bht); 2353 2354 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2355 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2356 2357 /* Stop pending T3-rtx and heartbeat timers */ 2358 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2359 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2360 2361 /* Delete non-primary peer ip addresses since we are transitioning 2362 * back to the COOKIE-WAIT state 2363 */ 2364 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2365 2366 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2367 * resend 2368 */ 2369 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2370 SCTP_TRANSPORT(asoc->peer.primary_path)); 2371 2372 /* Cast away the const modifier, as we want to just 2373 * rerun it through as a sideffect. 2374 */ 2375 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2376 2377 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2378 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2379 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2380 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2381 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2382 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2383 2384 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2385 2386 return SCTP_DISPOSITION_CONSUME; 2387 2388 nomem: 2389 return SCTP_DISPOSITION_NOMEM; 2390 } 2391 2392 /* 2393 * Process an ABORT. 2394 * 2395 * Section: 9.1 2396 * After checking the Verification Tag, the receiving endpoint shall 2397 * remove the association from its record, and shall report the 2398 * termination to its upper layer. 2399 * 2400 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2401 * B) Rules for packet carrying ABORT: 2402 * 2403 * - The endpoint shall always fill in the Verification Tag field of the 2404 * outbound packet with the destination endpoint's tag value if it 2405 * is known. 2406 * 2407 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2408 * MUST follow the procedure described in Section 8.4. 2409 * 2410 * - The receiver MUST accept the packet if the Verification Tag 2411 * matches either its own tag, OR the tag of its peer. Otherwise, the 2412 * receiver MUST silently discard the packet and take no further 2413 * action. 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 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2424 const struct sctp_endpoint *ep, 2425 const struct sctp_association *asoc, 2426 const sctp_subtype_t type, 2427 void *arg, 2428 sctp_cmd_seq_t *commands) 2429 { 2430 struct sctp_chunk *chunk = arg; 2431 2432 if (!sctp_vtag_verify_either(chunk, asoc)) 2433 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2434 2435 /* Make sure that the ABORT chunk has a valid length. 2436 * Since this is an ABORT chunk, we have to discard it 2437 * because of the following text: 2438 * RFC 2960, Section 3.3.7 2439 * If an endpoint receives an ABORT with a format error or for an 2440 * association that doesn't exist, it MUST silently discard it. 2441 * Because the length is "invalid", we can't really discard just 2442 * as we do not know its true length. So, to be safe, discard the 2443 * packet. 2444 */ 2445 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2446 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2447 2448 /* ADD-IP: Special case for ABORT chunks 2449 * F4) One special consideration is that ABORT Chunks arriving 2450 * destined to the IP address being deleted MUST be 2451 * ignored (see Section 5.3.1 for further details). 2452 */ 2453 if (SCTP_ADDR_DEL == 2454 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2455 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2456 2457 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2458 } 2459 2460 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2461 const struct sctp_endpoint *ep, 2462 const struct sctp_association *asoc, 2463 const sctp_subtype_t type, 2464 void *arg, 2465 sctp_cmd_seq_t *commands) 2466 { 2467 struct sctp_chunk *chunk = arg; 2468 unsigned int len; 2469 __be16 error = SCTP_ERROR_NO_ERROR; 2470 2471 /* See if we have an error cause code in the chunk. */ 2472 len = ntohs(chunk->chunk_hdr->length); 2473 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2474 2475 sctp_errhdr_t *err; 2476 sctp_walk_errors(err, chunk->chunk_hdr); 2477 if ((void *)err != (void *)chunk->chunk_end) 2478 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2479 2480 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2481 } 2482 2483 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2484 /* ASSOC_FAILED will DELETE_TCB. */ 2485 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2486 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2487 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2488 2489 return SCTP_DISPOSITION_ABORT; 2490 } 2491 2492 /* 2493 * Process an ABORT. (COOKIE-WAIT state) 2494 * 2495 * See sctp_sf_do_9_1_abort() above. 2496 */ 2497 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2498 const struct sctp_endpoint *ep, 2499 const struct sctp_association *asoc, 2500 const sctp_subtype_t type, 2501 void *arg, 2502 sctp_cmd_seq_t *commands) 2503 { 2504 struct sctp_chunk *chunk = arg; 2505 unsigned int len; 2506 __be16 error = SCTP_ERROR_NO_ERROR; 2507 2508 if (!sctp_vtag_verify_either(chunk, asoc)) 2509 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2510 2511 /* Make sure that the ABORT chunk has a valid length. 2512 * Since this is an ABORT chunk, we have to discard it 2513 * because of the following text: 2514 * RFC 2960, Section 3.3.7 2515 * If an endpoint receives an ABORT with a format error or for an 2516 * association that doesn't exist, it MUST silently discard it. 2517 * Because the length is "invalid", we can't really discard just 2518 * as we do not know its true length. So, to be safe, discard the 2519 * packet. 2520 */ 2521 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2522 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2523 2524 /* See if we have an error cause code in the chunk. */ 2525 len = ntohs(chunk->chunk_hdr->length); 2526 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2527 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2528 2529 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2530 chunk->transport); 2531 } 2532 2533 /* 2534 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2535 */ 2536 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2537 const struct sctp_endpoint *ep, 2538 const struct sctp_association *asoc, 2539 const sctp_subtype_t type, 2540 void *arg, 2541 sctp_cmd_seq_t *commands) 2542 { 2543 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2544 ENOPROTOOPT, asoc, 2545 (struct sctp_transport *)arg); 2546 } 2547 2548 /* 2549 * Process an ABORT. (COOKIE-ECHOED state) 2550 */ 2551 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2552 const struct sctp_endpoint *ep, 2553 const struct sctp_association *asoc, 2554 const sctp_subtype_t type, 2555 void *arg, 2556 sctp_cmd_seq_t *commands) 2557 { 2558 /* There is a single T1 timer, so we should be able to use 2559 * common function with the COOKIE-WAIT state. 2560 */ 2561 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2562 } 2563 2564 /* 2565 * Stop T1 timer and abort association with "INIT failed". 2566 * 2567 * This is common code called by several sctp_sf_*_abort() functions above. 2568 */ 2569 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2570 sctp_cmd_seq_t *commands, 2571 __be16 error, int sk_err, 2572 const struct sctp_association *asoc, 2573 struct sctp_transport *transport) 2574 { 2575 pr_debug("%s: ABORT received (INIT)\n", __func__); 2576 2577 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2578 SCTP_STATE(SCTP_STATE_CLOSED)); 2579 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2580 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2581 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2582 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2583 /* CMD_INIT_FAILED will DELETE_TCB. */ 2584 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2585 SCTP_PERR(error)); 2586 2587 return SCTP_DISPOSITION_ABORT; 2588 } 2589 2590 /* 2591 * sctp_sf_do_9_2_shut 2592 * 2593 * Section: 9.2 2594 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2595 * - enter the SHUTDOWN-RECEIVED state, 2596 * 2597 * - stop accepting new data from its SCTP user 2598 * 2599 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2600 * that all its outstanding DATA chunks have been received by the 2601 * SHUTDOWN sender. 2602 * 2603 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2604 * send a SHUTDOWN in response to a ULP request. And should discard 2605 * subsequent SHUTDOWN chunks. 2606 * 2607 * If there are still outstanding DATA chunks left, the SHUTDOWN 2608 * receiver shall continue to follow normal data transmission 2609 * procedures defined in Section 6 until all outstanding DATA chunks 2610 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2611 * new data from its SCTP user. 2612 * 2613 * Verification Tag: 8.5 Verification Tag [Normal verification] 2614 * 2615 * Inputs 2616 * (endpoint, asoc, chunk) 2617 * 2618 * Outputs 2619 * (asoc, reply_msg, msg_up, timers, counters) 2620 * 2621 * The return value is the disposition of the chunk. 2622 */ 2623 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2624 const struct sctp_endpoint *ep, 2625 const struct sctp_association *asoc, 2626 const sctp_subtype_t type, 2627 void *arg, 2628 sctp_cmd_seq_t *commands) 2629 { 2630 struct sctp_chunk *chunk = arg; 2631 sctp_shutdownhdr_t *sdh; 2632 sctp_disposition_t disposition; 2633 struct sctp_ulpevent *ev; 2634 __u32 ctsn; 2635 2636 if (!sctp_vtag_verify(chunk, asoc)) 2637 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2638 2639 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2640 if (!sctp_chunk_length_valid(chunk, 2641 sizeof(struct sctp_shutdown_chunk_t))) 2642 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2643 commands); 2644 2645 /* Convert the elaborate header. */ 2646 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2647 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2648 chunk->subh.shutdown_hdr = sdh; 2649 ctsn = ntohl(sdh->cum_tsn_ack); 2650 2651 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2652 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2653 asoc->ctsn_ack_point); 2654 2655 return SCTP_DISPOSITION_DISCARD; 2656 } 2657 2658 /* If Cumulative TSN Ack beyond the max tsn currently 2659 * send, terminating the association and respond to the 2660 * sender with an ABORT. 2661 */ 2662 if (!TSN_lt(ctsn, asoc->next_tsn)) 2663 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2664 2665 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2666 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2667 * inform the application that it should cease sending data. 2668 */ 2669 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2670 if (!ev) { 2671 disposition = SCTP_DISPOSITION_NOMEM; 2672 goto out; 2673 } 2674 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2675 2676 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2677 * - enter the SHUTDOWN-RECEIVED state, 2678 * - stop accepting new data from its SCTP user 2679 * 2680 * [This is implicit in the new state.] 2681 */ 2682 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2683 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2684 disposition = SCTP_DISPOSITION_CONSUME; 2685 2686 if (sctp_outq_is_empty(&asoc->outqueue)) { 2687 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2688 arg, commands); 2689 } 2690 2691 if (SCTP_DISPOSITION_NOMEM == disposition) 2692 goto out; 2693 2694 /* - verify, by checking the Cumulative TSN Ack field of the 2695 * chunk, that all its outstanding DATA chunks have been 2696 * received by the SHUTDOWN sender. 2697 */ 2698 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2699 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2700 2701 out: 2702 return disposition; 2703 } 2704 2705 /* 2706 * sctp_sf_do_9_2_shut_ctsn 2707 * 2708 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2709 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2710 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2711 * MUST be processed. 2712 */ 2713 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2714 const struct sctp_endpoint *ep, 2715 const struct sctp_association *asoc, 2716 const sctp_subtype_t type, 2717 void *arg, 2718 sctp_cmd_seq_t *commands) 2719 { 2720 struct sctp_chunk *chunk = arg; 2721 sctp_shutdownhdr_t *sdh; 2722 __u32 ctsn; 2723 2724 if (!sctp_vtag_verify(chunk, asoc)) 2725 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2726 2727 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2728 if (!sctp_chunk_length_valid(chunk, 2729 sizeof(struct sctp_shutdown_chunk_t))) 2730 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2731 commands); 2732 2733 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2734 ctsn = ntohl(sdh->cum_tsn_ack); 2735 2736 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2737 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2738 asoc->ctsn_ack_point); 2739 2740 return SCTP_DISPOSITION_DISCARD; 2741 } 2742 2743 /* If Cumulative TSN Ack beyond the max tsn currently 2744 * send, terminating the association and respond to the 2745 * sender with an ABORT. 2746 */ 2747 if (!TSN_lt(ctsn, asoc->next_tsn)) 2748 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2749 2750 /* verify, by checking the Cumulative TSN Ack field of the 2751 * chunk, that all its outstanding DATA chunks have been 2752 * received by the SHUTDOWN sender. 2753 */ 2754 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2755 SCTP_BE32(sdh->cum_tsn_ack)); 2756 2757 return SCTP_DISPOSITION_CONSUME; 2758 } 2759 2760 /* RFC 2960 9.2 2761 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2762 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2763 * transport addresses (either in the IP addresses or in the INIT chunk) 2764 * that belong to this association, it should discard the INIT chunk and 2765 * retransmit the SHUTDOWN ACK chunk. 2766 */ 2767 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2768 const struct sctp_endpoint *ep, 2769 const struct sctp_association *asoc, 2770 const sctp_subtype_t type, 2771 void *arg, 2772 sctp_cmd_seq_t *commands) 2773 { 2774 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2775 struct sctp_chunk *reply; 2776 2777 /* Make sure that the chunk has a valid length */ 2778 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2779 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2780 commands); 2781 2782 /* Since we are not going to really process this INIT, there 2783 * is no point in verifying chunk boundries. Just generate 2784 * the SHUTDOWN ACK. 2785 */ 2786 reply = sctp_make_shutdown_ack(asoc, chunk); 2787 if (NULL == reply) 2788 goto nomem; 2789 2790 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2791 * the T2-SHUTDOWN timer. 2792 */ 2793 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2794 2795 /* and restart the T2-shutdown timer. */ 2796 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2797 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2798 2799 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2800 2801 return SCTP_DISPOSITION_CONSUME; 2802 nomem: 2803 return SCTP_DISPOSITION_NOMEM; 2804 } 2805 2806 /* 2807 * sctp_sf_do_ecn_cwr 2808 * 2809 * Section: Appendix A: Explicit Congestion Notification 2810 * 2811 * CWR: 2812 * 2813 * RFC 2481 details a specific bit for a sender to send in the header of 2814 * its next outbound TCP segment to indicate to its peer that it has 2815 * reduced its congestion window. This is termed the CWR bit. For 2816 * SCTP the same indication is made by including the CWR chunk. 2817 * This chunk contains one data element, i.e. the TSN number that 2818 * was sent in the ECNE chunk. This element represents the lowest 2819 * TSN number in the datagram that was originally marked with the 2820 * CE bit. 2821 * 2822 * Verification Tag: 8.5 Verification Tag [Normal verification] 2823 * Inputs 2824 * (endpoint, asoc, chunk) 2825 * 2826 * Outputs 2827 * (asoc, reply_msg, msg_up, timers, counters) 2828 * 2829 * The return value is the disposition of the chunk. 2830 */ 2831 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2832 const struct sctp_endpoint *ep, 2833 const struct sctp_association *asoc, 2834 const sctp_subtype_t type, 2835 void *arg, 2836 sctp_cmd_seq_t *commands) 2837 { 2838 sctp_cwrhdr_t *cwr; 2839 struct sctp_chunk *chunk = arg; 2840 u32 lowest_tsn; 2841 2842 if (!sctp_vtag_verify(chunk, asoc)) 2843 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2844 2845 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2846 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2847 commands); 2848 2849 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2850 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2851 2852 lowest_tsn = ntohl(cwr->lowest_tsn); 2853 2854 /* Does this CWR ack the last sent congestion notification? */ 2855 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2856 /* Stop sending ECNE. */ 2857 sctp_add_cmd_sf(commands, 2858 SCTP_CMD_ECN_CWR, 2859 SCTP_U32(lowest_tsn)); 2860 } 2861 return SCTP_DISPOSITION_CONSUME; 2862 } 2863 2864 /* 2865 * sctp_sf_do_ecne 2866 * 2867 * Section: Appendix A: Explicit Congestion Notification 2868 * 2869 * ECN-Echo 2870 * 2871 * RFC 2481 details a specific bit for a receiver to send back in its 2872 * TCP acknowledgements to notify the sender of the Congestion 2873 * Experienced (CE) bit having arrived from the network. For SCTP this 2874 * same indication is made by including the ECNE chunk. This chunk 2875 * contains one data element, i.e. the lowest TSN associated with the IP 2876 * datagram marked with the CE bit..... 2877 * 2878 * Verification Tag: 8.5 Verification Tag [Normal verification] 2879 * Inputs 2880 * (endpoint, asoc, chunk) 2881 * 2882 * Outputs 2883 * (asoc, reply_msg, msg_up, timers, counters) 2884 * 2885 * The return value is the disposition of the chunk. 2886 */ 2887 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2888 const struct sctp_endpoint *ep, 2889 const struct sctp_association *asoc, 2890 const sctp_subtype_t type, 2891 void *arg, 2892 sctp_cmd_seq_t *commands) 2893 { 2894 sctp_ecnehdr_t *ecne; 2895 struct sctp_chunk *chunk = arg; 2896 2897 if (!sctp_vtag_verify(chunk, asoc)) 2898 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2899 2900 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2901 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2902 commands); 2903 2904 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2905 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2906 2907 /* If this is a newer ECNE than the last CWR packet we sent out */ 2908 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2909 SCTP_U32(ntohl(ecne->lowest_tsn))); 2910 2911 return SCTP_DISPOSITION_CONSUME; 2912 } 2913 2914 /* 2915 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2916 * 2917 * The SCTP endpoint MUST always acknowledge the reception of each valid 2918 * DATA chunk. 2919 * 2920 * The guidelines on delayed acknowledgement algorithm specified in 2921 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2922 * acknowledgement SHOULD be generated for at least every second packet 2923 * (not every second DATA chunk) received, and SHOULD be generated within 2924 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2925 * situations it may be beneficial for an SCTP transmitter to be more 2926 * conservative than the algorithms detailed in this document allow. 2927 * However, an SCTP transmitter MUST NOT be more aggressive than the 2928 * following algorithms allow. 2929 * 2930 * A SCTP receiver MUST NOT generate more than one SACK for every 2931 * incoming packet, other than to update the offered window as the 2932 * receiving application consumes new data. 2933 * 2934 * Verification Tag: 8.5 Verification Tag [Normal verification] 2935 * 2936 * Inputs 2937 * (endpoint, asoc, chunk) 2938 * 2939 * Outputs 2940 * (asoc, reply_msg, msg_up, timers, counters) 2941 * 2942 * The return value is the disposition of the chunk. 2943 */ 2944 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2945 const struct sctp_endpoint *ep, 2946 const struct sctp_association *asoc, 2947 const sctp_subtype_t type, 2948 void *arg, 2949 sctp_cmd_seq_t *commands) 2950 { 2951 struct sctp_chunk *chunk = arg; 2952 sctp_arg_t force = SCTP_NOFORCE(); 2953 int error; 2954 2955 if (!sctp_vtag_verify(chunk, asoc)) { 2956 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2957 SCTP_NULL()); 2958 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2959 } 2960 2961 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2962 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2963 commands); 2964 2965 error = sctp_eat_data(asoc, chunk, commands); 2966 switch (error) { 2967 case SCTP_IERROR_NO_ERROR: 2968 break; 2969 case SCTP_IERROR_HIGH_TSN: 2970 case SCTP_IERROR_BAD_STREAM: 2971 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2972 goto discard_noforce; 2973 case SCTP_IERROR_DUP_TSN: 2974 case SCTP_IERROR_IGNORE_TSN: 2975 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2976 goto discard_force; 2977 case SCTP_IERROR_NO_DATA: 2978 return SCTP_DISPOSITION_ABORT; 2979 case SCTP_IERROR_PROTO_VIOLATION: 2980 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 2981 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2982 default: 2983 BUG(); 2984 } 2985 2986 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2987 force = SCTP_FORCE(); 2988 2989 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 2990 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2991 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2992 } 2993 2994 /* If this is the last chunk in a packet, we need to count it 2995 * toward sack generation. Note that we need to SACK every 2996 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2997 * THEM. We elect to NOT generate SACK's if the chunk fails 2998 * the verification tag test. 2999 * 3000 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3001 * 3002 * The SCTP endpoint MUST always acknowledge the reception of 3003 * each valid DATA chunk. 3004 * 3005 * The guidelines on delayed acknowledgement algorithm 3006 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3007 * Specifically, an acknowledgement SHOULD be generated for at 3008 * least every second packet (not every second DATA chunk) 3009 * received, and SHOULD be generated within 200 ms of the 3010 * arrival of any unacknowledged DATA chunk. In some 3011 * situations it may be beneficial for an SCTP transmitter to 3012 * be more conservative than the algorithms detailed in this 3013 * document allow. However, an SCTP transmitter MUST NOT be 3014 * more aggressive than the following algorithms allow. 3015 */ 3016 if (chunk->end_of_packet) 3017 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3018 3019 return SCTP_DISPOSITION_CONSUME; 3020 3021 discard_force: 3022 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3023 * 3024 * When a packet arrives with duplicate DATA chunk(s) and with 3025 * no new DATA chunk(s), the endpoint MUST immediately send a 3026 * SACK with no delay. If a packet arrives with duplicate 3027 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3028 * MAY immediately send a SACK. Normally receipt of duplicate 3029 * DATA chunks will occur when the original SACK chunk was lost 3030 * and the peer's RTO has expired. The duplicate TSN number(s) 3031 * SHOULD be reported in the SACK as duplicate. 3032 */ 3033 /* In our case, we split the MAY SACK advice up whether or not 3034 * the last chunk is a duplicate.' 3035 */ 3036 if (chunk->end_of_packet) 3037 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3038 return SCTP_DISPOSITION_DISCARD; 3039 3040 discard_noforce: 3041 if (chunk->end_of_packet) 3042 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3043 3044 return SCTP_DISPOSITION_DISCARD; 3045 } 3046 3047 /* 3048 * sctp_sf_eat_data_fast_4_4 3049 * 3050 * Section: 4 (4) 3051 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3052 * DATA chunks without delay. 3053 * 3054 * Verification Tag: 8.5 Verification Tag [Normal verification] 3055 * Inputs 3056 * (endpoint, asoc, chunk) 3057 * 3058 * Outputs 3059 * (asoc, reply_msg, msg_up, timers, counters) 3060 * 3061 * The return value is the disposition of the chunk. 3062 */ 3063 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3064 const struct sctp_endpoint *ep, 3065 const struct sctp_association *asoc, 3066 const sctp_subtype_t type, 3067 void *arg, 3068 sctp_cmd_seq_t *commands) 3069 { 3070 struct sctp_chunk *chunk = arg; 3071 int error; 3072 3073 if (!sctp_vtag_verify(chunk, asoc)) { 3074 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3075 SCTP_NULL()); 3076 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3077 } 3078 3079 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3080 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3081 commands); 3082 3083 error = sctp_eat_data(asoc, chunk, commands); 3084 switch (error) { 3085 case SCTP_IERROR_NO_ERROR: 3086 case SCTP_IERROR_HIGH_TSN: 3087 case SCTP_IERROR_DUP_TSN: 3088 case SCTP_IERROR_IGNORE_TSN: 3089 case SCTP_IERROR_BAD_STREAM: 3090 break; 3091 case SCTP_IERROR_NO_DATA: 3092 return SCTP_DISPOSITION_ABORT; 3093 case SCTP_IERROR_PROTO_VIOLATION: 3094 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3095 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3096 default: 3097 BUG(); 3098 } 3099 3100 /* Go a head and force a SACK, since we are shutting down. */ 3101 3102 /* Implementor's Guide. 3103 * 3104 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3105 * respond to each received packet containing one or more DATA chunk(s) 3106 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3107 */ 3108 if (chunk->end_of_packet) { 3109 /* We must delay the chunk creation since the cumulative 3110 * TSN has not been updated yet. 3111 */ 3112 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3113 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3114 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3115 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3116 } 3117 3118 return SCTP_DISPOSITION_CONSUME; 3119 } 3120 3121 /* 3122 * Section: 6.2 Processing a Received SACK 3123 * D) Any time a SACK arrives, the endpoint performs the following: 3124 * 3125 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3126 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3127 * increasing, a SACK whose Cumulative TSN Ack is less than the 3128 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3129 * 3130 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3131 * of bytes still outstanding after processing the Cumulative TSN Ack 3132 * and the Gap Ack Blocks. 3133 * 3134 * iii) If the SACK is missing a TSN that was previously 3135 * acknowledged via a Gap Ack Block (e.g., the data receiver 3136 * reneged on the data), then mark the corresponding DATA chunk 3137 * as available for retransmit: Mark it as missing for fast 3138 * retransmit as described in Section 7.2.4 and if no retransmit 3139 * timer is running for the destination address to which the DATA 3140 * chunk was originally transmitted, then T3-rtx is started for 3141 * that destination address. 3142 * 3143 * Verification Tag: 8.5 Verification Tag [Normal verification] 3144 * 3145 * Inputs 3146 * (endpoint, asoc, chunk) 3147 * 3148 * Outputs 3149 * (asoc, reply_msg, msg_up, timers, counters) 3150 * 3151 * The return value is the disposition of the chunk. 3152 */ 3153 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3154 const struct sctp_endpoint *ep, 3155 const struct sctp_association *asoc, 3156 const sctp_subtype_t type, 3157 void *arg, 3158 sctp_cmd_seq_t *commands) 3159 { 3160 struct sctp_chunk *chunk = arg; 3161 sctp_sackhdr_t *sackh; 3162 __u32 ctsn; 3163 3164 if (!sctp_vtag_verify(chunk, asoc)) 3165 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3166 3167 /* Make sure that the SACK chunk has a valid length. */ 3168 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3169 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3170 commands); 3171 3172 /* Pull the SACK chunk from the data buffer */ 3173 sackh = sctp_sm_pull_sack(chunk); 3174 /* Was this a bogus SACK? */ 3175 if (!sackh) 3176 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3177 chunk->subh.sack_hdr = sackh; 3178 ctsn = ntohl(sackh->cum_tsn_ack); 3179 3180 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3181 * Ack Point, then drop the SACK. Since Cumulative TSN 3182 * Ack is monotonically increasing, a SACK whose 3183 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3184 * Point indicates an out-of-order SACK. 3185 */ 3186 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3187 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3188 asoc->ctsn_ack_point); 3189 3190 return SCTP_DISPOSITION_DISCARD; 3191 } 3192 3193 /* If Cumulative TSN Ack beyond the max tsn currently 3194 * send, terminating the association and respond to the 3195 * sender with an ABORT. 3196 */ 3197 if (!TSN_lt(ctsn, asoc->next_tsn)) 3198 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3199 3200 /* Return this SACK for further processing. */ 3201 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3202 3203 /* Note: We do the rest of the work on the PROCESS_SACK 3204 * sideeffect. 3205 */ 3206 return SCTP_DISPOSITION_CONSUME; 3207 } 3208 3209 /* 3210 * Generate an ABORT in response to a packet. 3211 * 3212 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3213 * 3214 * 8) The receiver should respond to the sender of the OOTB packet with 3215 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3216 * MUST fill in the Verification Tag field of the outbound packet 3217 * with the value found in the Verification Tag field of the OOTB 3218 * packet and set the T-bit in the Chunk Flags to indicate that the 3219 * Verification Tag is reflected. After sending this ABORT, the 3220 * receiver of the OOTB packet shall discard the OOTB packet and take 3221 * no further action. 3222 * 3223 * Verification Tag: 3224 * 3225 * The return value is the disposition of the chunk. 3226 */ 3227 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3228 const struct sctp_endpoint *ep, 3229 const struct sctp_association *asoc, 3230 const sctp_subtype_t type, 3231 void *arg, 3232 sctp_cmd_seq_t *commands) 3233 { 3234 struct sctp_packet *packet = NULL; 3235 struct sctp_chunk *chunk = arg; 3236 struct sctp_chunk *abort; 3237 3238 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3239 if (!packet) 3240 return SCTP_DISPOSITION_NOMEM; 3241 3242 /* Make an ABORT. The T bit will be set if the asoc 3243 * is NULL. 3244 */ 3245 abort = sctp_make_abort(asoc, chunk, 0); 3246 if (!abort) { 3247 sctp_ootb_pkt_free(packet); 3248 return SCTP_DISPOSITION_NOMEM; 3249 } 3250 3251 /* Reflect vtag if T-Bit is set */ 3252 if (sctp_test_T_bit(abort)) 3253 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3254 3255 /* Set the skb to the belonging sock for accounting. */ 3256 abort->skb->sk = ep->base.sk; 3257 3258 sctp_packet_append_chunk(packet, abort); 3259 3260 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3261 SCTP_PACKET(packet)); 3262 3263 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3264 3265 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3266 return SCTP_DISPOSITION_CONSUME; 3267 } 3268 3269 /* 3270 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3271 * event as ULP notification for each cause included in the chunk. 3272 * 3273 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3274 * 3275 * The return value is the disposition of the chunk. 3276 */ 3277 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3278 const struct sctp_endpoint *ep, 3279 const struct sctp_association *asoc, 3280 const sctp_subtype_t type, 3281 void *arg, 3282 sctp_cmd_seq_t *commands) 3283 { 3284 struct sctp_chunk *chunk = arg; 3285 sctp_errhdr_t *err; 3286 3287 if (!sctp_vtag_verify(chunk, asoc)) 3288 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3289 3290 /* Make sure that the ERROR chunk has a valid length. */ 3291 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3292 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3293 commands); 3294 sctp_walk_errors(err, chunk->chunk_hdr); 3295 if ((void *)err != (void *)chunk->chunk_end) 3296 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3297 (void *)err, commands); 3298 3299 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3300 SCTP_CHUNK(chunk)); 3301 3302 return SCTP_DISPOSITION_CONSUME; 3303 } 3304 3305 /* 3306 * Process an inbound SHUTDOWN ACK. 3307 * 3308 * From Section 9.2: 3309 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3310 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3311 * peer, and remove all record of the association. 3312 * 3313 * The return value is the disposition. 3314 */ 3315 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3316 const struct sctp_endpoint *ep, 3317 const struct sctp_association *asoc, 3318 const sctp_subtype_t type, 3319 void *arg, 3320 sctp_cmd_seq_t *commands) 3321 { 3322 struct sctp_chunk *chunk = arg; 3323 struct sctp_chunk *reply; 3324 struct sctp_ulpevent *ev; 3325 3326 if (!sctp_vtag_verify(chunk, asoc)) 3327 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3328 3329 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3330 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3331 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3332 commands); 3333 /* 10.2 H) SHUTDOWN COMPLETE notification 3334 * 3335 * When SCTP completes the shutdown procedures (section 9.2) this 3336 * notification is passed to the upper layer. 3337 */ 3338 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3339 0, 0, 0, NULL, GFP_ATOMIC); 3340 if (!ev) 3341 goto nomem; 3342 3343 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3344 reply = sctp_make_shutdown_complete(asoc, chunk); 3345 if (!reply) 3346 goto nomem_chunk; 3347 3348 /* Do all the commands now (after allocation), so that we 3349 * have consistent state if memory allocation failes 3350 */ 3351 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3352 3353 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3354 * stop the T2-shutdown timer, 3355 */ 3356 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3357 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3358 3359 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3360 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3361 3362 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3363 SCTP_STATE(SCTP_STATE_CLOSED)); 3364 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3365 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3366 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3367 3368 /* ...and remove all record of the association. */ 3369 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3370 return SCTP_DISPOSITION_DELETE_TCB; 3371 3372 nomem_chunk: 3373 sctp_ulpevent_free(ev); 3374 nomem: 3375 return SCTP_DISPOSITION_NOMEM; 3376 } 3377 3378 /* 3379 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3380 * 3381 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3382 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3383 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3384 * packet must fill in the Verification Tag field of the outbound 3385 * packet with the Verification Tag received in the SHUTDOWN ACK and 3386 * set the T-bit in the Chunk Flags to indicate that the Verification 3387 * Tag is reflected. 3388 * 3389 * 8) The receiver should respond to the sender of the OOTB packet with 3390 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3391 * MUST fill in the Verification Tag field of the outbound packet 3392 * with the value found in the Verification Tag field of the OOTB 3393 * packet and set the T-bit in the Chunk Flags to indicate that the 3394 * Verification Tag is reflected. After sending this ABORT, the 3395 * receiver of the OOTB packet shall discard the OOTB packet and take 3396 * no further action. 3397 */ 3398 sctp_disposition_t sctp_sf_ootb(struct net *net, 3399 const struct sctp_endpoint *ep, 3400 const struct sctp_association *asoc, 3401 const sctp_subtype_t type, 3402 void *arg, 3403 sctp_cmd_seq_t *commands) 3404 { 3405 struct sctp_chunk *chunk = arg; 3406 struct sk_buff *skb = chunk->skb; 3407 sctp_chunkhdr_t *ch; 3408 sctp_errhdr_t *err; 3409 __u8 *ch_end; 3410 int ootb_shut_ack = 0; 3411 int ootb_cookie_ack = 0; 3412 3413 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3414 3415 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3416 do { 3417 /* Report violation if the chunk is less then minimal */ 3418 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3419 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3420 commands); 3421 3422 /* Report violation if chunk len overflows */ 3423 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3424 if (ch_end > skb_tail_pointer(skb)) 3425 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3426 commands); 3427 3428 /* Now that we know we at least have a chunk header, 3429 * do things that are type appropriate. 3430 */ 3431 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3432 ootb_shut_ack = 1; 3433 3434 /* RFC 2960, Section 3.3.7 3435 * Moreover, under any circumstances, an endpoint that 3436 * receives an ABORT MUST NOT respond to that ABORT by 3437 * sending an ABORT of its own. 3438 */ 3439 if (SCTP_CID_ABORT == ch->type) 3440 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3441 3442 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3443 * or a COOKIE ACK the SCTP Packet should be silently 3444 * discarded. 3445 */ 3446 3447 if (SCTP_CID_COOKIE_ACK == ch->type) 3448 ootb_cookie_ack = 1; 3449 3450 if (SCTP_CID_ERROR == ch->type) { 3451 sctp_walk_errors(err, ch) { 3452 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3453 ootb_cookie_ack = 1; 3454 break; 3455 } 3456 } 3457 } 3458 3459 ch = (sctp_chunkhdr_t *) ch_end; 3460 } while (ch_end < skb_tail_pointer(skb)); 3461 3462 if (ootb_shut_ack) 3463 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3464 else if (ootb_cookie_ack) 3465 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3466 else 3467 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3468 } 3469 3470 /* 3471 * Handle an "Out of the blue" SHUTDOWN ACK. 3472 * 3473 * Section: 8.4 5, sctpimpguide 2.41. 3474 * 3475 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3476 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3477 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3478 * packet must fill in the Verification Tag field of the outbound 3479 * packet with the Verification Tag received in the SHUTDOWN ACK and 3480 * set the T-bit in the Chunk Flags to indicate that the Verification 3481 * Tag is reflected. 3482 * 3483 * Inputs 3484 * (endpoint, asoc, type, arg, commands) 3485 * 3486 * Outputs 3487 * (sctp_disposition_t) 3488 * 3489 * The return value is the disposition of the chunk. 3490 */ 3491 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3492 const struct sctp_endpoint *ep, 3493 const struct sctp_association *asoc, 3494 const sctp_subtype_t type, 3495 void *arg, 3496 sctp_cmd_seq_t *commands) 3497 { 3498 struct sctp_packet *packet = NULL; 3499 struct sctp_chunk *chunk = arg; 3500 struct sctp_chunk *shut; 3501 3502 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3503 if (!packet) 3504 return SCTP_DISPOSITION_NOMEM; 3505 3506 /* Make an SHUTDOWN_COMPLETE. 3507 * The T bit will be set if the asoc is NULL. 3508 */ 3509 shut = sctp_make_shutdown_complete(asoc, chunk); 3510 if (!shut) { 3511 sctp_ootb_pkt_free(packet); 3512 return SCTP_DISPOSITION_NOMEM; 3513 } 3514 3515 /* Reflect vtag if T-Bit is set */ 3516 if (sctp_test_T_bit(shut)) 3517 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3518 3519 /* Set the skb to the belonging sock for accounting. */ 3520 shut->skb->sk = ep->base.sk; 3521 3522 sctp_packet_append_chunk(packet, shut); 3523 3524 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3525 SCTP_PACKET(packet)); 3526 3527 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3528 3529 /* If the chunk length is invalid, we don't want to process 3530 * the reset of the packet. 3531 */ 3532 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3533 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3534 3535 /* We need to discard the rest of the packet to prevent 3536 * potential bomming attacks from additional bundled chunks. 3537 * This is documented in SCTP Threats ID. 3538 */ 3539 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3540 } 3541 3542 /* 3543 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3544 * 3545 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3546 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3547 * procedures in section 8.4 SHOULD be followed, in other words it 3548 * should be treated as an Out Of The Blue packet. 3549 * [This means that we do NOT check the Verification Tag on these 3550 * chunks. --piggy ] 3551 * 3552 */ 3553 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3554 const struct sctp_endpoint *ep, 3555 const struct sctp_association *asoc, 3556 const sctp_subtype_t type, 3557 void *arg, 3558 sctp_cmd_seq_t *commands) 3559 { 3560 struct sctp_chunk *chunk = arg; 3561 3562 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3563 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3564 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3565 commands); 3566 3567 /* Although we do have an association in this case, it corresponds 3568 * to a restarted association. So the packet is treated as an OOTB 3569 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3570 * called with a NULL association. 3571 */ 3572 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3573 3574 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3575 } 3576 3577 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3578 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3579 const struct sctp_endpoint *ep, 3580 const struct sctp_association *asoc, 3581 const sctp_subtype_t type, void *arg, 3582 sctp_cmd_seq_t *commands) 3583 { 3584 struct sctp_chunk *chunk = arg; 3585 struct sctp_chunk *asconf_ack = NULL; 3586 struct sctp_paramhdr *err_param = NULL; 3587 sctp_addiphdr_t *hdr; 3588 __u32 serial; 3589 3590 if (!sctp_vtag_verify(chunk, asoc)) { 3591 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3592 SCTP_NULL()); 3593 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3594 } 3595 3596 /* ADD-IP: Section 4.1.1 3597 * This chunk MUST be sent in an authenticated way by using 3598 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3599 * is received unauthenticated it MUST be silently discarded as 3600 * described in [I-D.ietf-tsvwg-sctp-auth]. 3601 */ 3602 if (!net->sctp.addip_noauth && !chunk->auth) 3603 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3604 3605 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3606 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3607 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3608 commands); 3609 3610 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3611 serial = ntohl(hdr->serial); 3612 3613 /* Verify the ASCONF chunk before processing it. */ 3614 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3615 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3616 (void *)err_param, commands); 3617 3618 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3619 * the endpoint stored in a new association variable 3620 * 'Peer-Serial-Number'. 3621 */ 3622 if (serial == asoc->peer.addip_serial + 1) { 3623 /* If this is the first instance of ASCONF in the packet, 3624 * we can clean our old ASCONF-ACKs. 3625 */ 3626 if (!chunk->has_asconf) 3627 sctp_assoc_clean_asconf_ack_cache(asoc); 3628 3629 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3630 * expected, process the ASCONF as described below and after 3631 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3632 * the response packet and cache a copy of it (in the event it 3633 * later needs to be retransmitted). 3634 * 3635 * Essentially, do V1-V5. 3636 */ 3637 asconf_ack = sctp_process_asconf((struct sctp_association *) 3638 asoc, chunk); 3639 if (!asconf_ack) 3640 return SCTP_DISPOSITION_NOMEM; 3641 } else if (serial < asoc->peer.addip_serial + 1) { 3642 /* ADDIP 5.2 E2) 3643 * If the value found in the Sequence Number is less than the 3644 * ('Peer- Sequence-Number' + 1), simply skip to the next 3645 * ASCONF, and include in the outbound response packet 3646 * any previously cached ASCONF-ACK response that was 3647 * sent and saved that matches the Sequence Number of the 3648 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3649 * Chunk exists. This will occur when an older ASCONF 3650 * arrives out of order. In such a case, the receiver 3651 * should skip the ASCONF Chunk and not include ASCONF-ACK 3652 * Chunk for that chunk. 3653 */ 3654 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3655 if (!asconf_ack) 3656 return SCTP_DISPOSITION_DISCARD; 3657 3658 /* Reset the transport so that we select the correct one 3659 * this time around. This is to make sure that we don't 3660 * accidentally use a stale transport that's been removed. 3661 */ 3662 asconf_ack->transport = NULL; 3663 } else { 3664 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3665 * it must be either a stale packet or from an attacker. 3666 */ 3667 return SCTP_DISPOSITION_DISCARD; 3668 } 3669 3670 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3671 * containing the ASCONF-ACK Chunks MUST be the source address of 3672 * the SCTP packet that held the ASCONF Chunks. 3673 * 3674 * To do this properly, we'll set the destination address of the chunk 3675 * and at the transmit time, will try look up the transport to use. 3676 * Since ASCONFs may be bundled, the correct transport may not be 3677 * created until we process the entire packet, thus this workaround. 3678 */ 3679 asconf_ack->dest = chunk->source; 3680 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3681 if (asoc->new_transport) { 3682 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3683 ((struct sctp_association *)asoc)->new_transport = NULL; 3684 } 3685 3686 return SCTP_DISPOSITION_CONSUME; 3687 } 3688 3689 /* 3690 * ADDIP Section 4.3 General rules for address manipulation 3691 * When building TLV parameters for the ASCONF Chunk that will add or 3692 * delete IP addresses the D0 to D13 rules should be applied: 3693 */ 3694 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3695 const struct sctp_endpoint *ep, 3696 const struct sctp_association *asoc, 3697 const sctp_subtype_t type, void *arg, 3698 sctp_cmd_seq_t *commands) 3699 { 3700 struct sctp_chunk *asconf_ack = arg; 3701 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3702 struct sctp_chunk *abort; 3703 struct sctp_paramhdr *err_param = NULL; 3704 sctp_addiphdr_t *addip_hdr; 3705 __u32 sent_serial, rcvd_serial; 3706 3707 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3708 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3709 SCTP_NULL()); 3710 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3711 } 3712 3713 /* ADD-IP, Section 4.1.2: 3714 * This chunk MUST be sent in an authenticated way by using 3715 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3716 * is received unauthenticated it MUST be silently discarded as 3717 * described in [I-D.ietf-tsvwg-sctp-auth]. 3718 */ 3719 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3720 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3721 3722 /* Make sure that the ADDIP chunk has a valid length. */ 3723 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3724 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3725 commands); 3726 3727 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3728 rcvd_serial = ntohl(addip_hdr->serial); 3729 3730 /* Verify the ASCONF-ACK chunk before processing it. */ 3731 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 3732 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3733 (void *)err_param, commands); 3734 3735 if (last_asconf) { 3736 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3737 sent_serial = ntohl(addip_hdr->serial); 3738 } else { 3739 sent_serial = asoc->addip_serial - 1; 3740 } 3741 3742 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3743 * equal to the next serial number to be used but no ASCONF chunk is 3744 * outstanding the endpoint MUST ABORT the association. Note that a 3745 * sequence number is greater than if it is no more than 2^^31-1 3746 * larger than the current sequence number (using serial arithmetic). 3747 */ 3748 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3749 !(asoc->addip_last_asconf)) { 3750 abort = sctp_make_abort(asoc, asconf_ack, 3751 sizeof(sctp_errhdr_t)); 3752 if (abort) { 3753 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3754 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3755 SCTP_CHUNK(abort)); 3756 } 3757 /* We are going to ABORT, so we might as well stop 3758 * processing the rest of the chunks in the packet. 3759 */ 3760 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3761 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3762 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3763 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3764 SCTP_ERROR(ECONNABORTED)); 3765 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3766 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3767 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3768 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3769 return SCTP_DISPOSITION_ABORT; 3770 } 3771 3772 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3773 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3774 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3775 3776 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3777 asconf_ack)) { 3778 /* Successfully processed ASCONF_ACK. We can 3779 * release the next asconf if we have one. 3780 */ 3781 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3782 SCTP_NULL()); 3783 return SCTP_DISPOSITION_CONSUME; 3784 } 3785 3786 abort = sctp_make_abort(asoc, asconf_ack, 3787 sizeof(sctp_errhdr_t)); 3788 if (abort) { 3789 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3790 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3791 SCTP_CHUNK(abort)); 3792 } 3793 /* We are going to ABORT, so we might as well stop 3794 * processing the rest of the chunks in the packet. 3795 */ 3796 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3797 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3798 SCTP_ERROR(ECONNABORTED)); 3799 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3800 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3801 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3802 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3803 return SCTP_DISPOSITION_ABORT; 3804 } 3805 3806 return SCTP_DISPOSITION_DISCARD; 3807 } 3808 3809 /* 3810 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3811 * 3812 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3813 * its cumulative TSN point to the value carried in the FORWARD TSN 3814 * chunk, and then MUST further advance its cumulative TSN point locally 3815 * if possible. 3816 * After the above processing, the data receiver MUST stop reporting any 3817 * missing TSNs earlier than or equal to the new cumulative TSN point. 3818 * 3819 * Verification Tag: 8.5 Verification Tag [Normal verification] 3820 * 3821 * The return value is the disposition of the chunk. 3822 */ 3823 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3824 const struct sctp_endpoint *ep, 3825 const struct sctp_association *asoc, 3826 const sctp_subtype_t type, 3827 void *arg, 3828 sctp_cmd_seq_t *commands) 3829 { 3830 struct sctp_chunk *chunk = arg; 3831 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3832 struct sctp_fwdtsn_skip *skip; 3833 __u16 len; 3834 __u32 tsn; 3835 3836 if (!sctp_vtag_verify(chunk, asoc)) { 3837 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3838 SCTP_NULL()); 3839 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3840 } 3841 3842 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3843 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3844 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3845 commands); 3846 3847 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3848 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3849 len = ntohs(chunk->chunk_hdr->length); 3850 len -= sizeof(struct sctp_chunkhdr); 3851 skb_pull(chunk->skb, len); 3852 3853 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3854 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3855 3856 /* The TSN is too high--silently discard the chunk and count on it 3857 * getting retransmitted later. 3858 */ 3859 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3860 goto discard_noforce; 3861 3862 /* Silently discard the chunk if stream-id is not valid */ 3863 sctp_walk_fwdtsn(skip, chunk) { 3864 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3865 goto discard_noforce; 3866 } 3867 3868 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3869 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3870 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3871 SCTP_CHUNK(chunk)); 3872 3873 /* Count this as receiving DATA. */ 3874 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3875 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3876 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3877 } 3878 3879 /* FIXME: For now send a SACK, but DATA processing may 3880 * send another. 3881 */ 3882 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3883 3884 return SCTP_DISPOSITION_CONSUME; 3885 3886 discard_noforce: 3887 return SCTP_DISPOSITION_DISCARD; 3888 } 3889 3890 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3891 struct net *net, 3892 const struct sctp_endpoint *ep, 3893 const struct sctp_association *asoc, 3894 const sctp_subtype_t type, 3895 void *arg, 3896 sctp_cmd_seq_t *commands) 3897 { 3898 struct sctp_chunk *chunk = arg; 3899 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3900 struct sctp_fwdtsn_skip *skip; 3901 __u16 len; 3902 __u32 tsn; 3903 3904 if (!sctp_vtag_verify(chunk, asoc)) { 3905 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3906 SCTP_NULL()); 3907 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3908 } 3909 3910 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3911 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3912 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3913 commands); 3914 3915 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3916 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3917 len = ntohs(chunk->chunk_hdr->length); 3918 len -= sizeof(struct sctp_chunkhdr); 3919 skb_pull(chunk->skb, len); 3920 3921 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3922 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3923 3924 /* The TSN is too high--silently discard the chunk and count on it 3925 * getting retransmitted later. 3926 */ 3927 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3928 goto gen_shutdown; 3929 3930 /* Silently discard the chunk if stream-id is not valid */ 3931 sctp_walk_fwdtsn(skip, chunk) { 3932 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3933 goto gen_shutdown; 3934 } 3935 3936 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3937 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3938 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3939 SCTP_CHUNK(chunk)); 3940 3941 /* Go a head and force a SACK, since we are shutting down. */ 3942 gen_shutdown: 3943 /* Implementor's Guide. 3944 * 3945 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3946 * respond to each received packet containing one or more DATA chunk(s) 3947 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3948 */ 3949 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3950 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3951 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3952 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3953 3954 return SCTP_DISPOSITION_CONSUME; 3955 } 3956 3957 /* 3958 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3959 * 3960 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3961 * Identifier field. If this algorithm was not specified by the 3962 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3963 * during association setup, the AUTH chunk and all chunks after it MUST 3964 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3965 * defined in Section 4.1. 3966 * 3967 * If an endpoint with no shared key receives a Shared Key Identifier 3968 * other than 0, it MUST silently discard all authenticated chunks. If 3969 * the endpoint has at least one endpoint pair shared key for the peer, 3970 * it MUST use the key specified by the Shared Key Identifier if a 3971 * key has been configured for that Shared Key Identifier. If no 3972 * endpoint pair shared key has been configured for that Shared Key 3973 * Identifier, all authenticated chunks MUST be silently discarded. 3974 * 3975 * Verification Tag: 8.5 Verification Tag [Normal verification] 3976 * 3977 * The return value is the disposition of the chunk. 3978 */ 3979 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 3980 const struct sctp_endpoint *ep, 3981 const struct sctp_association *asoc, 3982 const sctp_subtype_t type, 3983 struct sctp_chunk *chunk) 3984 { 3985 struct sctp_authhdr *auth_hdr; 3986 struct sctp_hmac *hmac; 3987 unsigned int sig_len; 3988 __u16 key_id; 3989 __u8 *save_digest; 3990 __u8 *digest; 3991 3992 /* Pull in the auth header, so we can do some more verification */ 3993 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3994 chunk->subh.auth_hdr = auth_hdr; 3995 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3996 3997 /* Make sure that we support the HMAC algorithm from the auth 3998 * chunk. 3999 */ 4000 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4001 return SCTP_IERROR_AUTH_BAD_HMAC; 4002 4003 /* Make sure that the provided shared key identifier has been 4004 * configured 4005 */ 4006 key_id = ntohs(auth_hdr->shkey_id); 4007 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4008 return SCTP_IERROR_AUTH_BAD_KEYID; 4009 4010 4011 /* Make sure that the length of the signature matches what 4012 * we expect. 4013 */ 4014 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4015 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4016 if (sig_len != hmac->hmac_len) 4017 return SCTP_IERROR_PROTO_VIOLATION; 4018 4019 /* Now that we've done validation checks, we can compute and 4020 * verify the hmac. The steps involved are: 4021 * 1. Save the digest from the chunk. 4022 * 2. Zero out the digest in the chunk. 4023 * 3. Compute the new digest 4024 * 4. Compare saved and new digests. 4025 */ 4026 digest = auth_hdr->hmac; 4027 skb_pull(chunk->skb, sig_len); 4028 4029 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4030 if (!save_digest) 4031 goto nomem; 4032 4033 memset(digest, 0, sig_len); 4034 4035 sctp_auth_calculate_hmac(asoc, chunk->skb, 4036 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4037 GFP_ATOMIC); 4038 4039 /* Discard the packet if the digests do not match */ 4040 if (memcmp(save_digest, digest, sig_len)) { 4041 kfree(save_digest); 4042 return SCTP_IERROR_BAD_SIG; 4043 } 4044 4045 kfree(save_digest); 4046 chunk->auth = 1; 4047 4048 return SCTP_IERROR_NO_ERROR; 4049 nomem: 4050 return SCTP_IERROR_NOMEM; 4051 } 4052 4053 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4054 const struct sctp_endpoint *ep, 4055 const struct sctp_association *asoc, 4056 const sctp_subtype_t type, 4057 void *arg, 4058 sctp_cmd_seq_t *commands) 4059 { 4060 struct sctp_authhdr *auth_hdr; 4061 struct sctp_chunk *chunk = arg; 4062 struct sctp_chunk *err_chunk; 4063 sctp_ierror_t error; 4064 4065 /* Make sure that the peer has AUTH capable */ 4066 if (!asoc->peer.auth_capable) 4067 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4068 4069 if (!sctp_vtag_verify(chunk, asoc)) { 4070 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4071 SCTP_NULL()); 4072 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4073 } 4074 4075 /* Make sure that the AUTH chunk has valid length. */ 4076 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4077 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4078 commands); 4079 4080 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4081 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4082 switch (error) { 4083 case SCTP_IERROR_AUTH_BAD_HMAC: 4084 /* Generate the ERROR chunk and discard the rest 4085 * of the packet 4086 */ 4087 err_chunk = sctp_make_op_error(asoc, chunk, 4088 SCTP_ERROR_UNSUP_HMAC, 4089 &auth_hdr->hmac_id, 4090 sizeof(__u16), 0); 4091 if (err_chunk) { 4092 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4093 SCTP_CHUNK(err_chunk)); 4094 } 4095 /* Fall Through */ 4096 case SCTP_IERROR_AUTH_BAD_KEYID: 4097 case SCTP_IERROR_BAD_SIG: 4098 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4099 4100 case SCTP_IERROR_PROTO_VIOLATION: 4101 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4102 commands); 4103 4104 case SCTP_IERROR_NOMEM: 4105 return SCTP_DISPOSITION_NOMEM; 4106 4107 default: /* Prevent gcc warnings */ 4108 break; 4109 } 4110 4111 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4112 struct sctp_ulpevent *ev; 4113 4114 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4115 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4116 4117 if (!ev) 4118 return -ENOMEM; 4119 4120 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4121 SCTP_ULPEVENT(ev)); 4122 } 4123 4124 return SCTP_DISPOSITION_CONSUME; 4125 } 4126 4127 /* 4128 * Process an unknown chunk. 4129 * 4130 * Section: 3.2. Also, 2.1 in the implementor's guide. 4131 * 4132 * Chunk Types are encoded such that the highest-order two bits specify 4133 * the action that must be taken if the processing endpoint does not 4134 * recognize the Chunk Type. 4135 * 4136 * 00 - Stop processing this SCTP packet and discard it, do not process 4137 * any further chunks within it. 4138 * 4139 * 01 - Stop processing this SCTP packet and discard it, do not process 4140 * any further chunks within it, and report the unrecognized 4141 * chunk in an 'Unrecognized Chunk Type'. 4142 * 4143 * 10 - Skip this chunk and continue processing. 4144 * 4145 * 11 - Skip this chunk and continue processing, but report in an ERROR 4146 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4147 * 4148 * The return value is the disposition of the chunk. 4149 */ 4150 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4151 const struct sctp_endpoint *ep, 4152 const struct sctp_association *asoc, 4153 const sctp_subtype_t type, 4154 void *arg, 4155 sctp_cmd_seq_t *commands) 4156 { 4157 struct sctp_chunk *unk_chunk = arg; 4158 struct sctp_chunk *err_chunk; 4159 sctp_chunkhdr_t *hdr; 4160 4161 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4162 4163 if (!sctp_vtag_verify(unk_chunk, asoc)) 4164 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4165 4166 /* Make sure that the chunk has a valid length. 4167 * Since we don't know the chunk type, we use a general 4168 * chunkhdr structure to make a comparison. 4169 */ 4170 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4171 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4172 commands); 4173 4174 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4175 case SCTP_CID_ACTION_DISCARD: 4176 /* Discard the packet. */ 4177 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4178 case SCTP_CID_ACTION_DISCARD_ERR: 4179 /* Generate an ERROR chunk as response. */ 4180 hdr = unk_chunk->chunk_hdr; 4181 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4182 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4183 SCTP_PAD4(ntohs(hdr->length)), 4184 0); 4185 if (err_chunk) { 4186 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4187 SCTP_CHUNK(err_chunk)); 4188 } 4189 4190 /* Discard the packet. */ 4191 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4192 return SCTP_DISPOSITION_CONSUME; 4193 case SCTP_CID_ACTION_SKIP: 4194 /* Skip the chunk. */ 4195 return SCTP_DISPOSITION_DISCARD; 4196 case SCTP_CID_ACTION_SKIP_ERR: 4197 /* Generate an ERROR chunk as response. */ 4198 hdr = unk_chunk->chunk_hdr; 4199 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4200 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4201 SCTP_PAD4(ntohs(hdr->length)), 4202 0); 4203 if (err_chunk) { 4204 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4205 SCTP_CHUNK(err_chunk)); 4206 } 4207 /* Skip the chunk. */ 4208 return SCTP_DISPOSITION_CONSUME; 4209 default: 4210 break; 4211 } 4212 4213 return SCTP_DISPOSITION_DISCARD; 4214 } 4215 4216 /* 4217 * Discard the chunk. 4218 * 4219 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4220 * [Too numerous to mention...] 4221 * Verification Tag: No verification needed. 4222 * Inputs 4223 * (endpoint, asoc, chunk) 4224 * 4225 * Outputs 4226 * (asoc, reply_msg, msg_up, timers, counters) 4227 * 4228 * The return value is the disposition of the chunk. 4229 */ 4230 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4231 const struct sctp_endpoint *ep, 4232 const struct sctp_association *asoc, 4233 const sctp_subtype_t type, 4234 void *arg, 4235 sctp_cmd_seq_t *commands) 4236 { 4237 struct sctp_chunk *chunk = arg; 4238 4239 /* Make sure that the chunk has a valid length. 4240 * Since we don't know the chunk type, we use a general 4241 * chunkhdr structure to make a comparison. 4242 */ 4243 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4244 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4245 commands); 4246 4247 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4248 4249 return SCTP_DISPOSITION_DISCARD; 4250 } 4251 4252 /* 4253 * Discard the whole packet. 4254 * 4255 * Section: 8.4 2) 4256 * 4257 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4258 * silently discard the OOTB packet and take no further action. 4259 * 4260 * Verification Tag: No verification necessary 4261 * 4262 * Inputs 4263 * (endpoint, asoc, chunk) 4264 * 4265 * Outputs 4266 * (asoc, reply_msg, msg_up, timers, counters) 4267 * 4268 * The return value is the disposition of the chunk. 4269 */ 4270 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4271 const struct sctp_endpoint *ep, 4272 const struct sctp_association *asoc, 4273 const sctp_subtype_t type, 4274 void *arg, 4275 sctp_cmd_seq_t *commands) 4276 { 4277 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4278 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4279 4280 return SCTP_DISPOSITION_CONSUME; 4281 } 4282 4283 4284 /* 4285 * The other end is violating protocol. 4286 * 4287 * Section: Not specified 4288 * Verification Tag: Not specified 4289 * Inputs 4290 * (endpoint, asoc, chunk) 4291 * 4292 * Outputs 4293 * (asoc, reply_msg, msg_up, timers, counters) 4294 * 4295 * We simply tag the chunk as a violation. The state machine will log 4296 * the violation and continue. 4297 */ 4298 sctp_disposition_t sctp_sf_violation(struct net *net, 4299 const struct sctp_endpoint *ep, 4300 const struct sctp_association *asoc, 4301 const sctp_subtype_t type, 4302 void *arg, 4303 sctp_cmd_seq_t *commands) 4304 { 4305 struct sctp_chunk *chunk = arg; 4306 4307 /* Make sure that the chunk has a valid length. */ 4308 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4309 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4310 commands); 4311 4312 return SCTP_DISPOSITION_VIOLATION; 4313 } 4314 4315 /* 4316 * Common function to handle a protocol violation. 4317 */ 4318 static sctp_disposition_t sctp_sf_abort_violation( 4319 struct net *net, 4320 const struct sctp_endpoint *ep, 4321 const struct sctp_association *asoc, 4322 void *arg, 4323 sctp_cmd_seq_t *commands, 4324 const __u8 *payload, 4325 const size_t paylen) 4326 { 4327 struct sctp_packet *packet = NULL; 4328 struct sctp_chunk *chunk = arg; 4329 struct sctp_chunk *abort = NULL; 4330 4331 /* SCTP-AUTH, Section 6.3: 4332 * It should be noted that if the receiver wants to tear 4333 * down an association in an authenticated way only, the 4334 * handling of malformed packets should not result in 4335 * tearing down the association. 4336 * 4337 * This means that if we only want to abort associations 4338 * in an authenticated way (i.e AUTH+ABORT), then we 4339 * can't destroy this association just because the packet 4340 * was malformed. 4341 */ 4342 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4343 goto discard; 4344 4345 /* Make the abort chunk. */ 4346 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4347 if (!abort) 4348 goto nomem; 4349 4350 if (asoc) { 4351 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4352 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4353 !asoc->peer.i.init_tag) { 4354 sctp_initack_chunk_t *initack; 4355 4356 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4357 if (!sctp_chunk_length_valid(chunk, 4358 sizeof(sctp_initack_chunk_t))) 4359 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4360 else { 4361 unsigned int inittag; 4362 4363 inittag = ntohl(initack->init_hdr.init_tag); 4364 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4365 SCTP_U32(inittag)); 4366 } 4367 } 4368 4369 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4370 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4371 4372 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4373 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4374 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4375 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4376 SCTP_ERROR(ECONNREFUSED)); 4377 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4378 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4379 } else { 4380 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4381 SCTP_ERROR(ECONNABORTED)); 4382 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4383 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4384 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4385 } 4386 } else { 4387 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4388 4389 if (!packet) 4390 goto nomem_pkt; 4391 4392 if (sctp_test_T_bit(abort)) 4393 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4394 4395 abort->skb->sk = ep->base.sk; 4396 4397 sctp_packet_append_chunk(packet, abort); 4398 4399 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4400 SCTP_PACKET(packet)); 4401 4402 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4403 } 4404 4405 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4406 4407 discard: 4408 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4409 return SCTP_DISPOSITION_ABORT; 4410 4411 nomem_pkt: 4412 sctp_chunk_free(abort); 4413 nomem: 4414 return SCTP_DISPOSITION_NOMEM; 4415 } 4416 4417 /* 4418 * Handle a protocol violation when the chunk length is invalid. 4419 * "Invalid" length is identified as smaller than the minimal length a 4420 * given chunk can be. For example, a SACK chunk has invalid length 4421 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4422 * 4423 * We inform the other end by sending an ABORT with a Protocol Violation 4424 * error code. 4425 * 4426 * Section: Not specified 4427 * Verification Tag: Nothing to do 4428 * Inputs 4429 * (endpoint, asoc, chunk) 4430 * 4431 * Outputs 4432 * (reply_msg, msg_up, counters) 4433 * 4434 * Generate an ABORT chunk and terminate the association. 4435 */ 4436 static sctp_disposition_t sctp_sf_violation_chunklen( 4437 struct net *net, 4438 const struct sctp_endpoint *ep, 4439 const struct sctp_association *asoc, 4440 const sctp_subtype_t type, 4441 void *arg, 4442 sctp_cmd_seq_t *commands) 4443 { 4444 static const char err_str[] = "The following chunk had invalid length:"; 4445 4446 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4447 sizeof(err_str)); 4448 } 4449 4450 /* 4451 * Handle a protocol violation when the parameter length is invalid. 4452 * If the length is smaller than the minimum length of a given parameter, 4453 * or accumulated length in multi parameters exceeds the end of the chunk, 4454 * the length is considered as invalid. 4455 */ 4456 static sctp_disposition_t sctp_sf_violation_paramlen( 4457 struct net *net, 4458 const struct sctp_endpoint *ep, 4459 const struct sctp_association *asoc, 4460 const sctp_subtype_t type, 4461 void *arg, void *ext, 4462 sctp_cmd_seq_t *commands) 4463 { 4464 struct sctp_chunk *chunk = arg; 4465 struct sctp_paramhdr *param = ext; 4466 struct sctp_chunk *abort = NULL; 4467 4468 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4469 goto discard; 4470 4471 /* Make the abort chunk. */ 4472 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4473 if (!abort) 4474 goto nomem; 4475 4476 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4477 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4478 4479 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4480 SCTP_ERROR(ECONNABORTED)); 4481 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4482 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4483 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4484 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4485 4486 discard: 4487 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4488 return SCTP_DISPOSITION_ABORT; 4489 nomem: 4490 return SCTP_DISPOSITION_NOMEM; 4491 } 4492 4493 /* Handle a protocol violation when the peer trying to advance the 4494 * cumulative tsn ack to a point beyond the max tsn currently sent. 4495 * 4496 * We inform the other end by sending an ABORT with a Protocol Violation 4497 * error code. 4498 */ 4499 static sctp_disposition_t sctp_sf_violation_ctsn( 4500 struct net *net, 4501 const struct sctp_endpoint *ep, 4502 const struct sctp_association *asoc, 4503 const sctp_subtype_t type, 4504 void *arg, 4505 sctp_cmd_seq_t *commands) 4506 { 4507 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4508 4509 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4510 sizeof(err_str)); 4511 } 4512 4513 /* Handle protocol violation of an invalid chunk bundling. For example, 4514 * when we have an association and we receive bundled INIT-ACK, or 4515 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4516 * statement from the specs. Additionally, there might be an attacker 4517 * on the path and we may not want to continue this communication. 4518 */ 4519 static sctp_disposition_t sctp_sf_violation_chunk( 4520 struct net *net, 4521 const struct sctp_endpoint *ep, 4522 const struct sctp_association *asoc, 4523 const sctp_subtype_t type, 4524 void *arg, 4525 sctp_cmd_seq_t *commands) 4526 { 4527 static const char err_str[] = "The following chunk violates protocol:"; 4528 4529 if (!asoc) 4530 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4531 4532 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4533 sizeof(err_str)); 4534 } 4535 /*************************************************************************** 4536 * These are the state functions for handling primitive (Section 10) events. 4537 ***************************************************************************/ 4538 /* 4539 * sctp_sf_do_prm_asoc 4540 * 4541 * Section: 10.1 ULP-to-SCTP 4542 * B) Associate 4543 * 4544 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4545 * outbound stream count) 4546 * -> association id [,destination transport addr list] [,outbound stream 4547 * count] 4548 * 4549 * This primitive allows the upper layer to initiate an association to a 4550 * specific peer endpoint. 4551 * 4552 * The peer endpoint shall be specified by one of the transport addresses 4553 * which defines the endpoint (see Section 1.4). If the local SCTP 4554 * instance has not been initialized, the ASSOCIATE is considered an 4555 * error. 4556 * [This is not relevant for the kernel implementation since we do all 4557 * initialization at boot time. It we hadn't initialized we wouldn't 4558 * get anywhere near this code.] 4559 * 4560 * An association id, which is a local handle to the SCTP association, 4561 * will be returned on successful establishment of the association. If 4562 * SCTP is not able to open an SCTP association with the peer endpoint, 4563 * an error is returned. 4564 * [In the kernel implementation, the struct sctp_association needs to 4565 * be created BEFORE causing this primitive to run.] 4566 * 4567 * Other association parameters may be returned, including the 4568 * complete destination transport addresses of the peer as well as the 4569 * outbound stream count of the local endpoint. One of the transport 4570 * address from the returned destination addresses will be selected by 4571 * the local endpoint as default primary path for sending SCTP packets 4572 * to this peer. The returned "destination transport addr list" can 4573 * be used by the ULP to change the default primary path or to force 4574 * sending a packet to a specific transport address. [All of this 4575 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4576 * function.] 4577 * 4578 * Mandatory attributes: 4579 * 4580 * o local SCTP instance name - obtained from the INITIALIZE operation. 4581 * [This is the argument asoc.] 4582 * o destination transport addr - specified as one of the transport 4583 * addresses of the peer endpoint with which the association is to be 4584 * established. 4585 * [This is asoc->peer.active_path.] 4586 * o outbound stream count - the number of outbound streams the ULP 4587 * would like to open towards this peer endpoint. 4588 * [BUG: This is not currently implemented.] 4589 * Optional attributes: 4590 * 4591 * None. 4592 * 4593 * The return value is a disposition. 4594 */ 4595 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4596 const struct sctp_endpoint *ep, 4597 const struct sctp_association *asoc, 4598 const sctp_subtype_t type, 4599 void *arg, 4600 sctp_cmd_seq_t *commands) 4601 { 4602 struct sctp_chunk *repl; 4603 struct sctp_association *my_asoc; 4604 4605 /* The comment below says that we enter COOKIE-WAIT AFTER 4606 * sending the INIT, but that doesn't actually work in our 4607 * implementation... 4608 */ 4609 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4610 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4611 4612 /* RFC 2960 5.1 Normal Establishment of an Association 4613 * 4614 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4615 * must provide its Verification Tag (Tag_A) in the Initiate 4616 * Tag field. Tag_A SHOULD be a random number in the range of 4617 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4618 */ 4619 4620 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4621 if (!repl) 4622 goto nomem; 4623 4624 /* Choose transport for INIT. */ 4625 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4626 SCTP_CHUNK(repl)); 4627 4628 /* Cast away the const modifier, as we want to just 4629 * rerun it through as a sideffect. 4630 */ 4631 my_asoc = (struct sctp_association *)asoc; 4632 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4633 4634 /* After sending the INIT, "A" starts the T1-init timer and 4635 * enters the COOKIE-WAIT state. 4636 */ 4637 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4638 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4639 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4640 return SCTP_DISPOSITION_CONSUME; 4641 4642 nomem: 4643 return SCTP_DISPOSITION_NOMEM; 4644 } 4645 4646 /* 4647 * Process the SEND primitive. 4648 * 4649 * Section: 10.1 ULP-to-SCTP 4650 * E) Send 4651 * 4652 * Format: SEND(association id, buffer address, byte count [,context] 4653 * [,stream id] [,life time] [,destination transport address] 4654 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4655 * -> result 4656 * 4657 * This is the main method to send user data via SCTP. 4658 * 4659 * Mandatory attributes: 4660 * 4661 * o association id - local handle to the SCTP association 4662 * 4663 * o buffer address - the location where the user message to be 4664 * transmitted is stored; 4665 * 4666 * o byte count - The size of the user data in number of bytes; 4667 * 4668 * Optional attributes: 4669 * 4670 * o context - an optional 32 bit integer that will be carried in the 4671 * sending failure notification to the ULP if the transportation of 4672 * this User Message fails. 4673 * 4674 * o stream id - to indicate which stream to send the data on. If not 4675 * specified, stream 0 will be used. 4676 * 4677 * o life time - specifies the life time of the user data. The user data 4678 * will not be sent by SCTP after the life time expires. This 4679 * parameter can be used to avoid efforts to transmit stale 4680 * user messages. SCTP notifies the ULP if the data cannot be 4681 * initiated to transport (i.e. sent to the destination via SCTP's 4682 * send primitive) within the life time variable. However, the 4683 * user data will be transmitted if SCTP has attempted to transmit a 4684 * chunk before the life time expired. 4685 * 4686 * o destination transport address - specified as one of the destination 4687 * transport addresses of the peer endpoint to which this packet 4688 * should be sent. Whenever possible, SCTP should use this destination 4689 * transport address for sending the packets, instead of the current 4690 * primary path. 4691 * 4692 * o unorder flag - this flag, if present, indicates that the user 4693 * would like the data delivered in an unordered fashion to the peer 4694 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4695 * message). 4696 * 4697 * o no-bundle flag - instructs SCTP not to bundle this user data with 4698 * other outbound DATA chunks. SCTP MAY still bundle even when 4699 * this flag is present, when faced with network congestion. 4700 * 4701 * o payload protocol-id - A 32 bit unsigned integer that is to be 4702 * passed to the peer indicating the type of payload protocol data 4703 * being transmitted. This value is passed as opaque data by SCTP. 4704 * 4705 * The return value is the disposition. 4706 */ 4707 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4708 const struct sctp_endpoint *ep, 4709 const struct sctp_association *asoc, 4710 const sctp_subtype_t type, 4711 void *arg, 4712 sctp_cmd_seq_t *commands) 4713 { 4714 struct sctp_datamsg *msg = arg; 4715 4716 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4717 return SCTP_DISPOSITION_CONSUME; 4718 } 4719 4720 /* 4721 * Process the SHUTDOWN primitive. 4722 * 4723 * Section: 10.1: 4724 * C) Shutdown 4725 * 4726 * Format: SHUTDOWN(association id) 4727 * -> result 4728 * 4729 * Gracefully closes an association. Any locally queued user data 4730 * will be delivered to the peer. The association will be terminated only 4731 * after the peer acknowledges all the SCTP packets sent. A success code 4732 * will be returned on successful termination of the association. If 4733 * attempting to terminate the association results in a failure, an error 4734 * code shall be returned. 4735 * 4736 * Mandatory attributes: 4737 * 4738 * o association id - local handle to the SCTP association 4739 * 4740 * Optional attributes: 4741 * 4742 * None. 4743 * 4744 * The return value is the disposition. 4745 */ 4746 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4747 struct net *net, 4748 const struct sctp_endpoint *ep, 4749 const struct sctp_association *asoc, 4750 const sctp_subtype_t type, 4751 void *arg, 4752 sctp_cmd_seq_t *commands) 4753 { 4754 int disposition; 4755 4756 /* From 9.2 Shutdown of an Association 4757 * Upon receipt of the SHUTDOWN primitive from its upper 4758 * layer, the endpoint enters SHUTDOWN-PENDING state and 4759 * remains there until all outstanding data has been 4760 * acknowledged by its peer. The endpoint accepts no new data 4761 * from its upper layer, but retransmits data to the far end 4762 * if necessary to fill gaps. 4763 */ 4764 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4765 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4766 4767 disposition = SCTP_DISPOSITION_CONSUME; 4768 if (sctp_outq_is_empty(&asoc->outqueue)) { 4769 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4770 arg, commands); 4771 } 4772 return disposition; 4773 } 4774 4775 /* 4776 * Process the ABORT primitive. 4777 * 4778 * Section: 10.1: 4779 * C) Abort 4780 * 4781 * Format: Abort(association id [, cause code]) 4782 * -> result 4783 * 4784 * Ungracefully closes an association. Any locally queued user data 4785 * will be discarded and an ABORT chunk is sent to the peer. A success code 4786 * will be returned on successful abortion of the association. If 4787 * attempting to abort the association results in a failure, an error 4788 * code shall be returned. 4789 * 4790 * Mandatory attributes: 4791 * 4792 * o association id - local handle to the SCTP association 4793 * 4794 * Optional attributes: 4795 * 4796 * o cause code - reason of the abort to be passed to the peer 4797 * 4798 * None. 4799 * 4800 * The return value is the disposition. 4801 */ 4802 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4803 struct net *net, 4804 const struct sctp_endpoint *ep, 4805 const struct sctp_association *asoc, 4806 const sctp_subtype_t type, 4807 void *arg, 4808 sctp_cmd_seq_t *commands) 4809 { 4810 /* From 9.1 Abort of an Association 4811 * Upon receipt of the ABORT primitive from its upper 4812 * layer, the endpoint enters CLOSED state and 4813 * discard all outstanding data has been 4814 * acknowledged by its peer. The endpoint accepts no new data 4815 * from its upper layer, but retransmits data to the far end 4816 * if necessary to fill gaps. 4817 */ 4818 struct sctp_chunk *abort = arg; 4819 4820 if (abort) 4821 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4822 4823 /* Even if we can't send the ABORT due to low memory delete the 4824 * TCB. This is a departure from our typical NOMEM handling. 4825 */ 4826 4827 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4828 SCTP_ERROR(ECONNABORTED)); 4829 /* Delete the established association. */ 4830 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4831 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4832 4833 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4834 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4835 4836 return SCTP_DISPOSITION_ABORT; 4837 } 4838 4839 /* We tried an illegal operation on an association which is closed. */ 4840 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4841 const struct sctp_endpoint *ep, 4842 const struct sctp_association *asoc, 4843 const sctp_subtype_t type, 4844 void *arg, 4845 sctp_cmd_seq_t *commands) 4846 { 4847 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4848 return SCTP_DISPOSITION_CONSUME; 4849 } 4850 4851 /* We tried an illegal operation on an association which is shutting 4852 * down. 4853 */ 4854 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4855 const struct sctp_endpoint *ep, 4856 const struct sctp_association *asoc, 4857 const sctp_subtype_t type, 4858 void *arg, 4859 sctp_cmd_seq_t *commands) 4860 { 4861 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4862 SCTP_ERROR(-ESHUTDOWN)); 4863 return SCTP_DISPOSITION_CONSUME; 4864 } 4865 4866 /* 4867 * sctp_cookie_wait_prm_shutdown 4868 * 4869 * Section: 4 Note: 2 4870 * Verification Tag: 4871 * Inputs 4872 * (endpoint, asoc) 4873 * 4874 * The RFC does not explicitly address this issue, but is the route through the 4875 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4876 * 4877 * Outputs 4878 * (timers) 4879 */ 4880 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4881 struct net *net, 4882 const struct sctp_endpoint *ep, 4883 const struct sctp_association *asoc, 4884 const sctp_subtype_t type, 4885 void *arg, 4886 sctp_cmd_seq_t *commands) 4887 { 4888 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4889 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4890 4891 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4892 SCTP_STATE(SCTP_STATE_CLOSED)); 4893 4894 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4895 4896 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4897 4898 return SCTP_DISPOSITION_DELETE_TCB; 4899 } 4900 4901 /* 4902 * sctp_cookie_echoed_prm_shutdown 4903 * 4904 * Section: 4 Note: 2 4905 * Verification Tag: 4906 * Inputs 4907 * (endpoint, asoc) 4908 * 4909 * The RFC does not explcitly address this issue, but is the route through the 4910 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4911 * 4912 * Outputs 4913 * (timers) 4914 */ 4915 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4916 struct net *net, 4917 const struct sctp_endpoint *ep, 4918 const struct sctp_association *asoc, 4919 const sctp_subtype_t type, 4920 void *arg, sctp_cmd_seq_t *commands) 4921 { 4922 /* There is a single T1 timer, so we should be able to use 4923 * common function with the COOKIE-WAIT state. 4924 */ 4925 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 4926 } 4927 4928 /* 4929 * sctp_sf_cookie_wait_prm_abort 4930 * 4931 * Section: 4 Note: 2 4932 * Verification Tag: 4933 * Inputs 4934 * (endpoint, asoc) 4935 * 4936 * The RFC does not explicitly address this issue, but is the route through the 4937 * state table when someone issues an abort while in COOKIE_WAIT state. 4938 * 4939 * Outputs 4940 * (timers) 4941 */ 4942 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4943 struct net *net, 4944 const struct sctp_endpoint *ep, 4945 const struct sctp_association *asoc, 4946 const sctp_subtype_t type, 4947 void *arg, 4948 sctp_cmd_seq_t *commands) 4949 { 4950 struct sctp_chunk *abort = arg; 4951 4952 /* Stop T1-init timer */ 4953 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4954 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4955 4956 if (abort) 4957 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4958 4959 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4960 SCTP_STATE(SCTP_STATE_CLOSED)); 4961 4962 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4963 4964 /* Even if we can't send the ABORT due to low memory delete the 4965 * TCB. This is a departure from our typical NOMEM handling. 4966 */ 4967 4968 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4969 SCTP_ERROR(ECONNREFUSED)); 4970 /* Delete the established association. */ 4971 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4972 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4973 4974 return SCTP_DISPOSITION_ABORT; 4975 } 4976 4977 /* 4978 * sctp_sf_cookie_echoed_prm_abort 4979 * 4980 * Section: 4 Note: 3 4981 * Verification Tag: 4982 * Inputs 4983 * (endpoint, asoc) 4984 * 4985 * The RFC does not explcitly address this issue, but is the route through the 4986 * state table when someone issues an abort while in COOKIE_ECHOED state. 4987 * 4988 * Outputs 4989 * (timers) 4990 */ 4991 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4992 struct net *net, 4993 const struct sctp_endpoint *ep, 4994 const struct sctp_association *asoc, 4995 const sctp_subtype_t type, 4996 void *arg, 4997 sctp_cmd_seq_t *commands) 4998 { 4999 /* There is a single T1 timer, so we should be able to use 5000 * common function with the COOKIE-WAIT state. 5001 */ 5002 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5003 } 5004 5005 /* 5006 * sctp_sf_shutdown_pending_prm_abort 5007 * 5008 * Inputs 5009 * (endpoint, asoc) 5010 * 5011 * The RFC does not explicitly address this issue, but is the route through the 5012 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5013 * 5014 * Outputs 5015 * (timers) 5016 */ 5017 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5018 struct net *net, 5019 const struct sctp_endpoint *ep, 5020 const struct sctp_association *asoc, 5021 const sctp_subtype_t type, 5022 void *arg, 5023 sctp_cmd_seq_t *commands) 5024 { 5025 /* Stop the T5-shutdown guard timer. */ 5026 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5027 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5028 5029 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5030 } 5031 5032 /* 5033 * sctp_sf_shutdown_sent_prm_abort 5034 * 5035 * Inputs 5036 * (endpoint, asoc) 5037 * 5038 * The RFC does not explicitly address this issue, but is the route through the 5039 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5040 * 5041 * Outputs 5042 * (timers) 5043 */ 5044 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5045 struct net *net, 5046 const struct sctp_endpoint *ep, 5047 const struct sctp_association *asoc, 5048 const sctp_subtype_t type, 5049 void *arg, 5050 sctp_cmd_seq_t *commands) 5051 { 5052 /* Stop the T2-shutdown timer. */ 5053 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5054 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5055 5056 /* Stop the T5-shutdown guard timer. */ 5057 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5058 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5059 5060 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5061 } 5062 5063 /* 5064 * sctp_sf_cookie_echoed_prm_abort 5065 * 5066 * Inputs 5067 * (endpoint, asoc) 5068 * 5069 * The RFC does not explcitly address this issue, but is the route through the 5070 * state table when someone issues an abort while in COOKIE_ECHOED state. 5071 * 5072 * Outputs 5073 * (timers) 5074 */ 5075 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5076 struct net *net, 5077 const struct sctp_endpoint *ep, 5078 const struct sctp_association *asoc, 5079 const sctp_subtype_t type, 5080 void *arg, 5081 sctp_cmd_seq_t *commands) 5082 { 5083 /* The same T2 timer, so we should be able to use 5084 * common function with the SHUTDOWN-SENT state. 5085 */ 5086 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5087 } 5088 5089 /* 5090 * Process the REQUESTHEARTBEAT primitive 5091 * 5092 * 10.1 ULP-to-SCTP 5093 * J) Request Heartbeat 5094 * 5095 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5096 * 5097 * -> result 5098 * 5099 * Instructs the local endpoint to perform a HeartBeat on the specified 5100 * destination transport address of the given association. The returned 5101 * result should indicate whether the transmission of the HEARTBEAT 5102 * chunk to the destination address is successful. 5103 * 5104 * Mandatory attributes: 5105 * 5106 * o association id - local handle to the SCTP association 5107 * 5108 * o destination transport address - the transport address of the 5109 * association on which a heartbeat should be issued. 5110 */ 5111 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5112 struct net *net, 5113 const struct sctp_endpoint *ep, 5114 const struct sctp_association *asoc, 5115 const sctp_subtype_t type, 5116 void *arg, 5117 sctp_cmd_seq_t *commands) 5118 { 5119 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5120 (struct sctp_transport *)arg, commands)) 5121 return SCTP_DISPOSITION_NOMEM; 5122 5123 /* 5124 * RFC 2960 (bis), section 8.3 5125 * 5126 * D) Request an on-demand HEARTBEAT on a specific destination 5127 * transport address of a given association. 5128 * 5129 * The endpoint should increment the respective error counter of 5130 * the destination transport address each time a HEARTBEAT is sent 5131 * to that address and not acknowledged within one RTO. 5132 * 5133 */ 5134 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5135 SCTP_TRANSPORT(arg)); 5136 return SCTP_DISPOSITION_CONSUME; 5137 } 5138 5139 /* 5140 * ADDIP Section 4.1 ASCONF Chunk Procedures 5141 * When an endpoint has an ASCONF signaled change to be sent to the 5142 * remote endpoint it should do A1 to A9 5143 */ 5144 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5145 const struct sctp_endpoint *ep, 5146 const struct sctp_association *asoc, 5147 const sctp_subtype_t type, 5148 void *arg, 5149 sctp_cmd_seq_t *commands) 5150 { 5151 struct sctp_chunk *chunk = arg; 5152 5153 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5154 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5155 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5156 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5157 return SCTP_DISPOSITION_CONSUME; 5158 } 5159 5160 /* 5161 * Ignore the primitive event 5162 * 5163 * The return value is the disposition of the primitive. 5164 */ 5165 sctp_disposition_t sctp_sf_ignore_primitive( 5166 struct net *net, 5167 const struct sctp_endpoint *ep, 5168 const struct sctp_association *asoc, 5169 const sctp_subtype_t type, 5170 void *arg, 5171 sctp_cmd_seq_t *commands) 5172 { 5173 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5174 type.primitive); 5175 5176 return SCTP_DISPOSITION_DISCARD; 5177 } 5178 5179 /*************************************************************************** 5180 * These are the state functions for the OTHER events. 5181 ***************************************************************************/ 5182 5183 /* 5184 * When the SCTP stack has no more user data to send or retransmit, this 5185 * notification is given to the user. Also, at the time when a user app 5186 * subscribes to this event, if there is no data to be sent or 5187 * retransmit, the stack will immediately send up this notification. 5188 */ 5189 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5190 struct net *net, 5191 const struct sctp_endpoint *ep, 5192 const struct sctp_association *asoc, 5193 const sctp_subtype_t type, 5194 void *arg, 5195 sctp_cmd_seq_t *commands) 5196 { 5197 struct sctp_ulpevent *event; 5198 5199 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5200 if (!event) 5201 return SCTP_DISPOSITION_NOMEM; 5202 5203 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5204 5205 return SCTP_DISPOSITION_CONSUME; 5206 } 5207 5208 /* 5209 * Start the shutdown negotiation. 5210 * 5211 * From Section 9.2: 5212 * Once all its outstanding data has been acknowledged, the endpoint 5213 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5214 * TSN Ack field the last sequential TSN it has received from the peer. 5215 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5216 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5217 * with the updated last sequential TSN received from its peer. 5218 * 5219 * The return value is the disposition. 5220 */ 5221 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5222 struct net *net, 5223 const struct sctp_endpoint *ep, 5224 const struct sctp_association *asoc, 5225 const sctp_subtype_t type, 5226 void *arg, 5227 sctp_cmd_seq_t *commands) 5228 { 5229 struct sctp_chunk *reply; 5230 5231 /* Once all its outstanding data has been acknowledged, the 5232 * endpoint shall send a SHUTDOWN chunk to its peer including 5233 * in the Cumulative TSN Ack field the last sequential TSN it 5234 * has received from the peer. 5235 */ 5236 reply = sctp_make_shutdown(asoc, NULL); 5237 if (!reply) 5238 goto nomem; 5239 5240 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5241 * T2-shutdown timer. 5242 */ 5243 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5244 5245 /* It shall then start the T2-shutdown timer */ 5246 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5247 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5248 5249 /* RFC 4960 Section 9.2 5250 * The sender of the SHUTDOWN MAY also start an overall guard timer 5251 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5252 */ 5253 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5254 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5255 5256 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5257 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5258 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5259 5260 /* and enter the SHUTDOWN-SENT state. */ 5261 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5262 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5263 5264 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5265 * 5266 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5267 * or SHUTDOWN-ACK. 5268 */ 5269 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5270 5271 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5272 5273 return SCTP_DISPOSITION_CONSUME; 5274 5275 nomem: 5276 return SCTP_DISPOSITION_NOMEM; 5277 } 5278 5279 /* 5280 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5281 * 5282 * From Section 9.2: 5283 * 5284 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5285 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5286 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5287 * endpoint must re-send the SHUTDOWN ACK. 5288 * 5289 * The return value is the disposition. 5290 */ 5291 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5292 struct net *net, 5293 const struct sctp_endpoint *ep, 5294 const struct sctp_association *asoc, 5295 const sctp_subtype_t type, 5296 void *arg, 5297 sctp_cmd_seq_t *commands) 5298 { 5299 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5300 struct sctp_chunk *reply; 5301 5302 /* There are 2 ways of getting here: 5303 * 1) called in response to a SHUTDOWN chunk 5304 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5305 * 5306 * For the case (2), the arg parameter is set to NULL. We need 5307 * to check that we have a chunk before accessing it's fields. 5308 */ 5309 if (chunk) { 5310 if (!sctp_vtag_verify(chunk, asoc)) 5311 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5312 5313 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5314 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5315 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5316 commands); 5317 } 5318 5319 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5320 * shall send a SHUTDOWN ACK ... 5321 */ 5322 reply = sctp_make_shutdown_ack(asoc, chunk); 5323 if (!reply) 5324 goto nomem; 5325 5326 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5327 * the T2-shutdown timer. 5328 */ 5329 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5330 5331 /* and start/restart a T2-shutdown timer of its own, */ 5332 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5333 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5334 5335 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5336 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5337 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5338 5339 /* Enter the SHUTDOWN-ACK-SENT state. */ 5340 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5341 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5342 5343 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5344 * 5345 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5346 * or SHUTDOWN-ACK. 5347 */ 5348 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5349 5350 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5351 5352 return SCTP_DISPOSITION_CONSUME; 5353 5354 nomem: 5355 return SCTP_DISPOSITION_NOMEM; 5356 } 5357 5358 /* 5359 * Ignore the event defined as other 5360 * 5361 * The return value is the disposition of the event. 5362 */ 5363 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5364 const struct sctp_endpoint *ep, 5365 const struct sctp_association *asoc, 5366 const sctp_subtype_t type, 5367 void *arg, 5368 sctp_cmd_seq_t *commands) 5369 { 5370 pr_debug("%s: the event other type:%d is ignored\n", 5371 __func__, type.other); 5372 5373 return SCTP_DISPOSITION_DISCARD; 5374 } 5375 5376 /************************************************************ 5377 * These are the state functions for handling timeout events. 5378 ************************************************************/ 5379 5380 /* 5381 * RTX Timeout 5382 * 5383 * Section: 6.3.3 Handle T3-rtx Expiration 5384 * 5385 * Whenever the retransmission timer T3-rtx expires for a destination 5386 * address, do the following: 5387 * [See below] 5388 * 5389 * The return value is the disposition of the chunk. 5390 */ 5391 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5392 const struct sctp_endpoint *ep, 5393 const struct sctp_association *asoc, 5394 const sctp_subtype_t type, 5395 void *arg, 5396 sctp_cmd_seq_t *commands) 5397 { 5398 struct sctp_transport *transport = arg; 5399 5400 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5401 5402 if (asoc->overall_error_count >= asoc->max_retrans) { 5403 if (asoc->peer.zero_window_announced && 5404 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5405 /* 5406 * We are here likely because the receiver had its rwnd 5407 * closed for a while and we have not been able to 5408 * transmit the locally queued data within the maximum 5409 * retransmission attempts limit. Start the T5 5410 * shutdown guard timer to give the receiver one last 5411 * chance and some additional time to recover before 5412 * aborting. 5413 */ 5414 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5415 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5416 } else { 5417 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5418 SCTP_ERROR(ETIMEDOUT)); 5419 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5420 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5421 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5422 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5423 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5424 return SCTP_DISPOSITION_DELETE_TCB; 5425 } 5426 } 5427 5428 /* E1) For the destination address for which the timer 5429 * expires, adjust its ssthresh with rules defined in Section 5430 * 7.2.3 and set the cwnd <- MTU. 5431 */ 5432 5433 /* E2) For the destination address for which the timer 5434 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5435 * maximum value discussed in rule C7 above (RTO.max) may be 5436 * used to provide an upper bound to this doubling operation. 5437 */ 5438 5439 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5440 * outstanding DATA chunks for the address for which the 5441 * T3-rtx has expired will fit into a single packet, subject 5442 * to the MTU constraint for the path corresponding to the 5443 * destination transport address to which the retransmission 5444 * is being sent (this may be different from the address for 5445 * which the timer expires [see Section 6.4]). Call this 5446 * value K. Bundle and retransmit those K DATA chunks in a 5447 * single packet to the destination endpoint. 5448 * 5449 * Note: Any DATA chunks that were sent to the address for 5450 * which the T3-rtx timer expired but did not fit in one MTU 5451 * (rule E3 above), should be marked for retransmission and 5452 * sent as soon as cwnd allows (normally when a SACK arrives). 5453 */ 5454 5455 /* Do some failure management (Section 8.2). */ 5456 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5457 5458 /* NB: Rules E4 and F1 are implicit in R1. */ 5459 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5460 5461 return SCTP_DISPOSITION_CONSUME; 5462 } 5463 5464 /* 5465 * Generate delayed SACK on timeout 5466 * 5467 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5468 * 5469 * The guidelines on delayed acknowledgement algorithm specified in 5470 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5471 * acknowledgement SHOULD be generated for at least every second packet 5472 * (not every second DATA chunk) received, and SHOULD be generated 5473 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5474 * some situations it may be beneficial for an SCTP transmitter to be 5475 * more conservative than the algorithms detailed in this document 5476 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5477 * the following algorithms allow. 5478 */ 5479 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5480 const struct sctp_endpoint *ep, 5481 const struct sctp_association *asoc, 5482 const sctp_subtype_t type, 5483 void *arg, 5484 sctp_cmd_seq_t *commands) 5485 { 5486 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5487 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5488 return SCTP_DISPOSITION_CONSUME; 5489 } 5490 5491 /* 5492 * sctp_sf_t1_init_timer_expire 5493 * 5494 * Section: 4 Note: 2 5495 * Verification Tag: 5496 * Inputs 5497 * (endpoint, asoc) 5498 * 5499 * RFC 2960 Section 4 Notes 5500 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5501 * and re-start the T1-init timer without changing state. This MUST 5502 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5503 * endpoint MUST abort the initialization process and report the 5504 * error to SCTP user. 5505 * 5506 * Outputs 5507 * (timers, events) 5508 * 5509 */ 5510 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5511 const struct sctp_endpoint *ep, 5512 const struct sctp_association *asoc, 5513 const sctp_subtype_t type, 5514 void *arg, 5515 sctp_cmd_seq_t *commands) 5516 { 5517 struct sctp_chunk *repl = NULL; 5518 struct sctp_bind_addr *bp; 5519 int attempts = asoc->init_err_counter + 1; 5520 5521 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5522 5523 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5524 5525 if (attempts <= asoc->max_init_attempts) { 5526 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5527 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5528 if (!repl) 5529 return SCTP_DISPOSITION_NOMEM; 5530 5531 /* Choose transport for INIT. */ 5532 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5533 SCTP_CHUNK(repl)); 5534 5535 /* Issue a sideeffect to do the needed accounting. */ 5536 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5537 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5538 5539 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5540 } else { 5541 pr_debug("%s: giving up on INIT, attempts:%d " 5542 "max_init_attempts:%d\n", __func__, attempts, 5543 asoc->max_init_attempts); 5544 5545 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5546 SCTP_ERROR(ETIMEDOUT)); 5547 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5548 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5549 return SCTP_DISPOSITION_DELETE_TCB; 5550 } 5551 5552 return SCTP_DISPOSITION_CONSUME; 5553 } 5554 5555 /* 5556 * sctp_sf_t1_cookie_timer_expire 5557 * 5558 * Section: 4 Note: 2 5559 * Verification Tag: 5560 * Inputs 5561 * (endpoint, asoc) 5562 * 5563 * RFC 2960 Section 4 Notes 5564 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5565 * COOKIE ECHO and re-start the T1-cookie timer without changing 5566 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5567 * After that, the endpoint MUST abort the initialization process and 5568 * report the error to SCTP user. 5569 * 5570 * Outputs 5571 * (timers, events) 5572 * 5573 */ 5574 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5575 const struct sctp_endpoint *ep, 5576 const struct sctp_association *asoc, 5577 const sctp_subtype_t type, 5578 void *arg, 5579 sctp_cmd_seq_t *commands) 5580 { 5581 struct sctp_chunk *repl = NULL; 5582 int attempts = asoc->init_err_counter + 1; 5583 5584 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5585 5586 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5587 5588 if (attempts <= asoc->max_init_attempts) { 5589 repl = sctp_make_cookie_echo(asoc, NULL); 5590 if (!repl) 5591 return SCTP_DISPOSITION_NOMEM; 5592 5593 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5594 SCTP_CHUNK(repl)); 5595 /* Issue a sideeffect to do the needed accounting. */ 5596 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5597 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5598 5599 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5600 } else { 5601 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5602 SCTP_ERROR(ETIMEDOUT)); 5603 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5604 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5605 return SCTP_DISPOSITION_DELETE_TCB; 5606 } 5607 5608 return SCTP_DISPOSITION_CONSUME; 5609 } 5610 5611 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5612 * with the updated last sequential TSN received from its peer. 5613 * 5614 * An endpoint should limit the number of retransmissions of the 5615 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5616 * If this threshold is exceeded the endpoint should destroy the TCB and 5617 * MUST report the peer endpoint unreachable to the upper layer (and 5618 * thus the association enters the CLOSED state). The reception of any 5619 * packet from its peer (i.e. as the peer sends all of its queued DATA 5620 * chunks) should clear the endpoint's retransmission count and restart 5621 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5622 * all of its queued DATA chunks that have not yet been sent. 5623 */ 5624 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5625 const struct sctp_endpoint *ep, 5626 const struct sctp_association *asoc, 5627 const sctp_subtype_t type, 5628 void *arg, 5629 sctp_cmd_seq_t *commands) 5630 { 5631 struct sctp_chunk *reply = NULL; 5632 5633 pr_debug("%s: timer T2 expired\n", __func__); 5634 5635 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5636 5637 ((struct sctp_association *)asoc)->shutdown_retries++; 5638 5639 if (asoc->overall_error_count >= asoc->max_retrans) { 5640 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5641 SCTP_ERROR(ETIMEDOUT)); 5642 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5643 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5644 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5645 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5646 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5647 return SCTP_DISPOSITION_DELETE_TCB; 5648 } 5649 5650 switch (asoc->state) { 5651 case SCTP_STATE_SHUTDOWN_SENT: 5652 reply = sctp_make_shutdown(asoc, NULL); 5653 break; 5654 5655 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5656 reply = sctp_make_shutdown_ack(asoc, NULL); 5657 break; 5658 5659 default: 5660 BUG(); 5661 break; 5662 } 5663 5664 if (!reply) 5665 goto nomem; 5666 5667 /* Do some failure management (Section 8.2). 5668 * If we remove the transport an SHUTDOWN was last sent to, don't 5669 * do failure management. 5670 */ 5671 if (asoc->shutdown_last_sent_to) 5672 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5673 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5674 5675 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5676 * the T2-shutdown timer. 5677 */ 5678 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5679 5680 /* Restart the T2-shutdown timer. */ 5681 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5682 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5683 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5684 return SCTP_DISPOSITION_CONSUME; 5685 5686 nomem: 5687 return SCTP_DISPOSITION_NOMEM; 5688 } 5689 5690 /* 5691 * ADDIP Section 4.1 ASCONF CHunk Procedures 5692 * If the T4 RTO timer expires the endpoint should do B1 to B5 5693 */ 5694 sctp_disposition_t sctp_sf_t4_timer_expire( 5695 struct net *net, 5696 const struct sctp_endpoint *ep, 5697 const struct sctp_association *asoc, 5698 const sctp_subtype_t type, 5699 void *arg, 5700 sctp_cmd_seq_t *commands) 5701 { 5702 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5703 struct sctp_transport *transport = chunk->transport; 5704 5705 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5706 5707 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5708 * detection on the appropriate destination address as defined in 5709 * RFC2960 [5] section 8.1 and 8.2. 5710 */ 5711 if (transport) 5712 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5713 SCTP_TRANSPORT(transport)); 5714 5715 /* Reconfig T4 timer and transport. */ 5716 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5717 5718 /* ADDIP 4.1 B2) Increment the association error counters and perform 5719 * endpoint failure detection on the association as defined in 5720 * RFC2960 [5] section 8.1 and 8.2. 5721 * association error counter is incremented in SCTP_CMD_STRIKE. 5722 */ 5723 if (asoc->overall_error_count >= asoc->max_retrans) { 5724 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5725 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5726 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5727 SCTP_ERROR(ETIMEDOUT)); 5728 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5729 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5730 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5731 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5732 return SCTP_DISPOSITION_ABORT; 5733 } 5734 5735 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5736 * the ASCONF chunk was sent by doubling the RTO timer value. 5737 * This is done in SCTP_CMD_STRIKE. 5738 */ 5739 5740 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5741 * choose an alternate destination address (please refer to RFC2960 5742 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5743 * chunk, it MUST be the same (including its serial number) as the last 5744 * ASCONF sent. 5745 */ 5746 sctp_chunk_hold(asoc->addip_last_asconf); 5747 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5748 SCTP_CHUNK(asoc->addip_last_asconf)); 5749 5750 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5751 * destination is selected, then the RTO used will be that of the new 5752 * destination address. 5753 */ 5754 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5755 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5756 5757 return SCTP_DISPOSITION_CONSUME; 5758 } 5759 5760 /* sctpimpguide-05 Section 2.12.2 5761 * The sender of the SHUTDOWN MAY also start an overall guard timer 5762 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5763 * At the expiration of this timer the sender SHOULD abort the association 5764 * by sending an ABORT chunk. 5765 */ 5766 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5767 const struct sctp_endpoint *ep, 5768 const struct sctp_association *asoc, 5769 const sctp_subtype_t type, 5770 void *arg, 5771 sctp_cmd_seq_t *commands) 5772 { 5773 struct sctp_chunk *reply = NULL; 5774 5775 pr_debug("%s: timer T5 expired\n", __func__); 5776 5777 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5778 5779 reply = sctp_make_abort(asoc, NULL, 0); 5780 if (!reply) 5781 goto nomem; 5782 5783 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5784 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5785 SCTP_ERROR(ETIMEDOUT)); 5786 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5787 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5788 5789 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5790 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5791 5792 return SCTP_DISPOSITION_DELETE_TCB; 5793 nomem: 5794 return SCTP_DISPOSITION_NOMEM; 5795 } 5796 5797 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5798 * the association is automatically closed by starting the shutdown process. 5799 * The work that needs to be done is same as when SHUTDOWN is initiated by 5800 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5801 */ 5802 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5803 struct net *net, 5804 const struct sctp_endpoint *ep, 5805 const struct sctp_association *asoc, 5806 const sctp_subtype_t type, 5807 void *arg, 5808 sctp_cmd_seq_t *commands) 5809 { 5810 int disposition; 5811 5812 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5813 5814 /* From 9.2 Shutdown of an Association 5815 * Upon receipt of the SHUTDOWN primitive from its upper 5816 * layer, the endpoint enters SHUTDOWN-PENDING state and 5817 * remains there until all outstanding data has been 5818 * acknowledged by its peer. The endpoint accepts no new data 5819 * from its upper layer, but retransmits data to the far end 5820 * if necessary to fill gaps. 5821 */ 5822 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5823 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5824 5825 disposition = SCTP_DISPOSITION_CONSUME; 5826 if (sctp_outq_is_empty(&asoc->outqueue)) { 5827 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5828 arg, commands); 5829 } 5830 return disposition; 5831 } 5832 5833 /***************************************************************************** 5834 * These are sa state functions which could apply to all types of events. 5835 ****************************************************************************/ 5836 5837 /* 5838 * This table entry is not implemented. 5839 * 5840 * Inputs 5841 * (endpoint, asoc, chunk) 5842 * 5843 * The return value is the disposition of the chunk. 5844 */ 5845 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5846 const struct sctp_endpoint *ep, 5847 const struct sctp_association *asoc, 5848 const sctp_subtype_t type, 5849 void *arg, 5850 sctp_cmd_seq_t *commands) 5851 { 5852 return SCTP_DISPOSITION_NOT_IMPL; 5853 } 5854 5855 /* 5856 * This table entry represents a bug. 5857 * 5858 * Inputs 5859 * (endpoint, asoc, chunk) 5860 * 5861 * The return value is the disposition of the chunk. 5862 */ 5863 sctp_disposition_t sctp_sf_bug(struct net *net, 5864 const struct sctp_endpoint *ep, 5865 const struct sctp_association *asoc, 5866 const sctp_subtype_t type, 5867 void *arg, 5868 sctp_cmd_seq_t *commands) 5869 { 5870 return SCTP_DISPOSITION_BUG; 5871 } 5872 5873 /* 5874 * This table entry represents the firing of a timer in the wrong state. 5875 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5876 * when the association is in the wrong state. This event should 5877 * be ignored, so as to prevent any rearming of the timer. 5878 * 5879 * Inputs 5880 * (endpoint, asoc, chunk) 5881 * 5882 * The return value is the disposition of the chunk. 5883 */ 5884 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5885 const struct sctp_endpoint *ep, 5886 const struct sctp_association *asoc, 5887 const sctp_subtype_t type, 5888 void *arg, 5889 sctp_cmd_seq_t *commands) 5890 { 5891 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 5892 5893 return SCTP_DISPOSITION_CONSUME; 5894 } 5895 5896 /******************************************************************** 5897 * 2nd Level Abstractions 5898 ********************************************************************/ 5899 5900 /* Pull the SACK chunk based on the SACK header. */ 5901 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5902 { 5903 struct sctp_sackhdr *sack; 5904 unsigned int len; 5905 __u16 num_blocks; 5906 __u16 num_dup_tsns; 5907 5908 /* Protect ourselves from reading too far into 5909 * the skb from a bogus sender. 5910 */ 5911 sack = (struct sctp_sackhdr *) chunk->skb->data; 5912 5913 num_blocks = ntohs(sack->num_gap_ack_blocks); 5914 num_dup_tsns = ntohs(sack->num_dup_tsns); 5915 len = sizeof(struct sctp_sackhdr); 5916 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5917 if (len > chunk->skb->len) 5918 return NULL; 5919 5920 skb_pull(chunk->skb, len); 5921 5922 return sack; 5923 } 5924 5925 /* Create an ABORT packet to be sent as a response, with the specified 5926 * error causes. 5927 */ 5928 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 5929 const struct sctp_endpoint *ep, 5930 const struct sctp_association *asoc, 5931 struct sctp_chunk *chunk, 5932 const void *payload, 5933 size_t paylen) 5934 { 5935 struct sctp_packet *packet; 5936 struct sctp_chunk *abort; 5937 5938 packet = sctp_ootb_pkt_new(net, asoc, chunk); 5939 5940 if (packet) { 5941 /* Make an ABORT. 5942 * The T bit will be set if the asoc is NULL. 5943 */ 5944 abort = sctp_make_abort(asoc, chunk, paylen); 5945 if (!abort) { 5946 sctp_ootb_pkt_free(packet); 5947 return NULL; 5948 } 5949 5950 /* Reflect vtag if T-Bit is set */ 5951 if (sctp_test_T_bit(abort)) 5952 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5953 5954 /* Add specified error causes, i.e., payload, to the 5955 * end of the chunk. 5956 */ 5957 sctp_addto_chunk(abort, paylen, payload); 5958 5959 /* Set the skb to the belonging sock for accounting. */ 5960 abort->skb->sk = ep->base.sk; 5961 5962 sctp_packet_append_chunk(packet, abort); 5963 5964 } 5965 5966 return packet; 5967 } 5968 5969 /* Allocate a packet for responding in the OOTB conditions. */ 5970 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 5971 const struct sctp_association *asoc, 5972 const struct sctp_chunk *chunk) 5973 { 5974 struct sctp_packet *packet; 5975 struct sctp_transport *transport; 5976 __u16 sport; 5977 __u16 dport; 5978 __u32 vtag; 5979 5980 /* Get the source and destination port from the inbound packet. */ 5981 sport = ntohs(chunk->sctp_hdr->dest); 5982 dport = ntohs(chunk->sctp_hdr->source); 5983 5984 /* The V-tag is going to be the same as the inbound packet if no 5985 * association exists, otherwise, use the peer's vtag. 5986 */ 5987 if (asoc) { 5988 /* Special case the INIT-ACK as there is no peer's vtag 5989 * yet. 5990 */ 5991 switch (chunk->chunk_hdr->type) { 5992 case SCTP_CID_INIT_ACK: 5993 { 5994 sctp_initack_chunk_t *initack; 5995 5996 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5997 vtag = ntohl(initack->init_hdr.init_tag); 5998 break; 5999 } 6000 default: 6001 vtag = asoc->peer.i.init_tag; 6002 break; 6003 } 6004 } else { 6005 /* Special case the INIT and stale COOKIE_ECHO as there is no 6006 * vtag yet. 6007 */ 6008 switch (chunk->chunk_hdr->type) { 6009 case SCTP_CID_INIT: 6010 { 6011 sctp_init_chunk_t *init; 6012 6013 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6014 vtag = ntohl(init->init_hdr.init_tag); 6015 break; 6016 } 6017 default: 6018 vtag = ntohl(chunk->sctp_hdr->vtag); 6019 break; 6020 } 6021 } 6022 6023 /* Make a transport for the bucket, Eliza... */ 6024 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6025 if (!transport) 6026 goto nomem; 6027 6028 /* Cache a route for the transport with the chunk's destination as 6029 * the source address. 6030 */ 6031 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6032 sctp_sk(net->sctp.ctl_sock)); 6033 6034 packet = &transport->packet; 6035 sctp_packet_init(packet, transport, sport, dport); 6036 sctp_packet_config(packet, vtag, 0); 6037 6038 return packet; 6039 6040 nomem: 6041 return NULL; 6042 } 6043 6044 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6045 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6046 { 6047 sctp_transport_free(packet->transport); 6048 } 6049 6050 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6051 static void sctp_send_stale_cookie_err(struct net *net, 6052 const struct sctp_endpoint *ep, 6053 const struct sctp_association *asoc, 6054 const struct sctp_chunk *chunk, 6055 sctp_cmd_seq_t *commands, 6056 struct sctp_chunk *err_chunk) 6057 { 6058 struct sctp_packet *packet; 6059 6060 if (err_chunk) { 6061 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6062 if (packet) { 6063 struct sctp_signed_cookie *cookie; 6064 6065 /* Override the OOTB vtag from the cookie. */ 6066 cookie = chunk->subh.cookie_hdr; 6067 packet->vtag = cookie->c.peer_vtag; 6068 6069 /* Set the skb to the belonging sock for accounting. */ 6070 err_chunk->skb->sk = ep->base.sk; 6071 sctp_packet_append_chunk(packet, err_chunk); 6072 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6073 SCTP_PACKET(packet)); 6074 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6075 } else 6076 sctp_chunk_free (err_chunk); 6077 } 6078 } 6079 6080 6081 /* Process a data chunk */ 6082 static int sctp_eat_data(const struct sctp_association *asoc, 6083 struct sctp_chunk *chunk, 6084 sctp_cmd_seq_t *commands) 6085 { 6086 sctp_datahdr_t *data_hdr; 6087 struct sctp_chunk *err; 6088 size_t datalen; 6089 sctp_verb_t deliver; 6090 int tmp; 6091 __u32 tsn; 6092 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6093 struct sock *sk = asoc->base.sk; 6094 struct net *net = sock_net(sk); 6095 u16 ssn; 6096 u16 sid; 6097 u8 ordered = 0; 6098 6099 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6100 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6101 6102 tsn = ntohl(data_hdr->tsn); 6103 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6104 6105 /* ASSERT: Now skb->data is really the user data. */ 6106 6107 /* Process ECN based congestion. 6108 * 6109 * Since the chunk structure is reused for all chunks within 6110 * a packet, we use ecn_ce_done to track if we've already 6111 * done CE processing for this packet. 6112 * 6113 * We need to do ECN processing even if we plan to discard the 6114 * chunk later. 6115 */ 6116 6117 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6118 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6119 chunk->ecn_ce_done = 1; 6120 6121 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6122 /* Do real work as sideffect. */ 6123 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6124 SCTP_U32(tsn)); 6125 } 6126 } 6127 6128 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6129 if (tmp < 0) { 6130 /* The TSN is too high--silently discard the chunk and 6131 * count on it getting retransmitted later. 6132 */ 6133 if (chunk->asoc) 6134 chunk->asoc->stats.outofseqtsns++; 6135 return SCTP_IERROR_HIGH_TSN; 6136 } else if (tmp > 0) { 6137 /* This is a duplicate. Record it. */ 6138 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6139 return SCTP_IERROR_DUP_TSN; 6140 } 6141 6142 /* This is a new TSN. */ 6143 6144 /* Discard if there is no room in the receive window. 6145 * Actually, allow a little bit of overflow (up to a MTU). 6146 */ 6147 datalen = ntohs(chunk->chunk_hdr->length); 6148 datalen -= sizeof(sctp_data_chunk_t); 6149 6150 deliver = SCTP_CMD_CHUNK_ULP; 6151 6152 /* Think about partial delivery. */ 6153 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6154 6155 /* Even if we don't accept this chunk there is 6156 * memory pressure. 6157 */ 6158 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6159 } 6160 6161 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6162 * seems a bit troublesome in that frag_point varies based on 6163 * PMTU. In cases, such as loopback, this might be a rather 6164 * large spill over. 6165 */ 6166 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6167 (datalen > asoc->rwnd + asoc->frag_point))) { 6168 6169 /* If this is the next TSN, consider reneging to make 6170 * room. Note: Playing nice with a confused sender. A 6171 * malicious sender can still eat up all our buffer 6172 * space and in the future we may want to detect and 6173 * do more drastic reneging. 6174 */ 6175 if (sctp_tsnmap_has_gap(map) && 6176 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6177 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6178 deliver = SCTP_CMD_RENEGE; 6179 } else { 6180 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6181 __func__, tsn, datalen, asoc->rwnd); 6182 6183 return SCTP_IERROR_IGNORE_TSN; 6184 } 6185 } 6186 6187 /* 6188 * Also try to renege to limit our memory usage in the event that 6189 * we are under memory pressure 6190 * If we can't renege, don't worry about it, the sk_rmem_schedule 6191 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6192 * memory usage too much 6193 */ 6194 if (*sk->sk_prot_creator->memory_pressure) { 6195 if (sctp_tsnmap_has_gap(map) && 6196 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6197 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6198 __func__, tsn); 6199 deliver = SCTP_CMD_RENEGE; 6200 } 6201 } 6202 6203 /* 6204 * Section 3.3.10.9 No User Data (9) 6205 * 6206 * Cause of error 6207 * --------------- 6208 * No User Data: This error cause is returned to the originator of a 6209 * DATA chunk if a received DATA chunk has no user data. 6210 */ 6211 if (unlikely(0 == datalen)) { 6212 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6213 if (err) { 6214 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6215 SCTP_CHUNK(err)); 6216 } 6217 /* We are going to ABORT, so we might as well stop 6218 * processing the rest of the chunks in the packet. 6219 */ 6220 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6221 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6222 SCTP_ERROR(ECONNABORTED)); 6223 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6224 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6225 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6226 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6227 return SCTP_IERROR_NO_DATA; 6228 } 6229 6230 chunk->data_accepted = 1; 6231 6232 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6233 * if we renege and the chunk arrives again. 6234 */ 6235 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6236 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6237 if (chunk->asoc) 6238 chunk->asoc->stats.iuodchunks++; 6239 } else { 6240 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6241 if (chunk->asoc) 6242 chunk->asoc->stats.iodchunks++; 6243 ordered = 1; 6244 } 6245 6246 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6247 * 6248 * If an endpoint receive a DATA chunk with an invalid stream 6249 * identifier, it shall acknowledge the reception of the DATA chunk 6250 * following the normal procedure, immediately send an ERROR chunk 6251 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6252 * and discard the DATA chunk. 6253 */ 6254 sid = ntohs(data_hdr->stream); 6255 if (sid >= asoc->c.sinit_max_instreams) { 6256 /* Mark tsn as received even though we drop it */ 6257 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6258 6259 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6260 &data_hdr->stream, 6261 sizeof(data_hdr->stream), 6262 sizeof(u16)); 6263 if (err) 6264 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6265 SCTP_CHUNK(err)); 6266 return SCTP_IERROR_BAD_STREAM; 6267 } 6268 6269 /* Check to see if the SSN is possible for this TSN. 6270 * The biggest gap we can record is 4K wide. Since SSNs wrap 6271 * at an unsigned short, there is no way that an SSN can 6272 * wrap and for a valid TSN. We can simply check if the current 6273 * SSN is smaller then the next expected one. If it is, it wrapped 6274 * and is invalid. 6275 */ 6276 ssn = ntohs(data_hdr->ssn); 6277 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6278 return SCTP_IERROR_PROTO_VIOLATION; 6279 } 6280 6281 /* Send the data up to the user. Note: Schedule the 6282 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6283 * chunk needs the updated rwnd. 6284 */ 6285 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6286 6287 return SCTP_IERROR_NO_ERROR; 6288 } 6289