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: 1 = Valid length 164 * 0 = Invalid length 165 * 166 */ 167 static inline int 168 sctp_chunk_length_valid(struct sctp_chunk *chunk, 169 __u16 required_length) 170 { 171 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 172 173 if (unlikely(chunk_length < required_length)) 174 return 0; 175 176 return 1; 177 } 178 179 /********************************************************** 180 * These are the state functions for handling chunk events. 181 **********************************************************/ 182 183 /* 184 * Process the final SHUTDOWN COMPLETE. 185 * 186 * Section: 4 (C) (diagram), 9.2 187 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 188 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 189 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 190 * should stop the T2-shutdown timer and remove all knowledge of the 191 * association (and thus the association enters the CLOSED state). 192 * 193 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 194 * C) Rules for packet carrying SHUTDOWN COMPLETE: 195 * ... 196 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 197 * if the Verification Tag field of the packet matches its own tag and 198 * the T bit is not set 199 * OR 200 * it is set to its peer's tag and the T bit is set in the Chunk 201 * Flags. 202 * Otherwise, the receiver MUST silently discard the packet 203 * and take no further action. An endpoint MUST ignore the 204 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 205 * 206 * Inputs 207 * (endpoint, asoc, chunk) 208 * 209 * Outputs 210 * (asoc, reply_msg, msg_up, timers, counters) 211 * 212 * The return value is the disposition of the chunk. 213 */ 214 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 215 const struct sctp_endpoint *ep, 216 const struct sctp_association *asoc, 217 const sctp_subtype_t type, 218 void *arg, 219 sctp_cmd_seq_t *commands) 220 { 221 struct sctp_chunk *chunk = arg; 222 struct sctp_ulpevent *ev; 223 224 if (!sctp_vtag_verify_either(chunk, asoc)) 225 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 226 227 /* RFC 2960 6.10 Bundling 228 * 229 * An endpoint MUST NOT bundle INIT, INIT ACK or 230 * SHUTDOWN COMPLETE with any other chunks. 231 */ 232 if (!chunk->singleton) 233 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 234 235 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 236 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 237 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 238 commands); 239 240 /* RFC 2960 10.2 SCTP-to-ULP 241 * 242 * H) SHUTDOWN COMPLETE notification 243 * 244 * When SCTP completes the shutdown procedures (section 9.2) this 245 * notification is passed to the upper layer. 246 */ 247 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 248 0, 0, 0, NULL, GFP_ATOMIC); 249 if (ev) 250 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 251 SCTP_ULPEVENT(ev)); 252 253 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 254 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 255 * not the chunk should be discarded. If the endpoint is in 256 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 257 * T2-shutdown timer and remove all knowledge of the 258 * association (and thus the association enters the CLOSED 259 * state). 260 */ 261 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 262 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 263 264 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 265 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 266 267 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 268 SCTP_STATE(SCTP_STATE_CLOSED)); 269 270 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 271 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 272 273 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 274 275 return SCTP_DISPOSITION_DELETE_TCB; 276 } 277 278 /* 279 * Respond to a normal INIT chunk. 280 * We are the side that is being asked for an association. 281 * 282 * Section: 5.1 Normal Establishment of an Association, B 283 * B) "Z" shall respond immediately with an INIT ACK chunk. The 284 * destination IP address of the INIT ACK MUST be set to the source 285 * IP address of the INIT to which this INIT ACK is responding. In 286 * the response, besides filling in other parameters, "Z" must set the 287 * Verification Tag field to Tag_A, and also provide its own 288 * Verification Tag (Tag_Z) in the Initiate Tag field. 289 * 290 * Verification Tag: Must be 0. 291 * 292 * Inputs 293 * (endpoint, asoc, chunk) 294 * 295 * Outputs 296 * (asoc, reply_msg, msg_up, timers, counters) 297 * 298 * The return value is the disposition of the chunk. 299 */ 300 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 301 const struct sctp_endpoint *ep, 302 const struct sctp_association *asoc, 303 const sctp_subtype_t type, 304 void *arg, 305 sctp_cmd_seq_t *commands) 306 { 307 struct sctp_chunk *chunk = arg; 308 struct sctp_chunk *repl; 309 struct sctp_association *new_asoc; 310 struct sctp_chunk *err_chunk; 311 struct sctp_packet *packet; 312 sctp_unrecognized_param_t *unk_param; 313 int len; 314 315 /* 6.10 Bundling 316 * An endpoint MUST NOT bundle INIT, INIT ACK or 317 * SHUTDOWN COMPLETE with any other chunks. 318 * 319 * IG Section 2.11.2 320 * Furthermore, we require that the receiver of an INIT chunk MUST 321 * enforce these rules by silently discarding an arriving packet 322 * with an INIT chunk that is bundled with other chunks. 323 */ 324 if (!chunk->singleton) 325 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 326 327 /* If the packet is an OOTB packet which is temporarily on the 328 * control endpoint, respond with an ABORT. 329 */ 330 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 331 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 332 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 333 } 334 335 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 336 * Tag. 337 */ 338 if (chunk->sctp_hdr->vtag != 0) 339 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 340 341 /* Make sure that the INIT chunk has a valid length. 342 * Normally, this would cause an ABORT with a Protocol Violation 343 * error, but since we don't have an association, we'll 344 * just discard the packet. 345 */ 346 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 348 349 /* If the INIT is coming toward a closing socket, we'll send back 350 * and ABORT. Essentially, this catches the race of INIT being 351 * backloged to the socket at the same time as the user isses close(). 352 * Since the socket and all its associations are going away, we 353 * can treat this OOTB 354 */ 355 if (sctp_sstate(ep->base.sk, CLOSING)) 356 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 357 358 /* Verify the INIT chunk before processing it. */ 359 err_chunk = NULL; 360 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 361 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 362 &err_chunk)) { 363 /* This chunk contains fatal error. It is to be discarded. 364 * Send an ABORT, with causes if there is any. 365 */ 366 if (err_chunk) { 367 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 368 (__u8 *)(err_chunk->chunk_hdr) + 369 sizeof(sctp_chunkhdr_t), 370 ntohs(err_chunk->chunk_hdr->length) - 371 sizeof(sctp_chunkhdr_t)); 372 373 sctp_chunk_free(err_chunk); 374 375 if (packet) { 376 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 377 SCTP_PACKET(packet)); 378 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 379 return SCTP_DISPOSITION_CONSUME; 380 } else { 381 return SCTP_DISPOSITION_NOMEM; 382 } 383 } else { 384 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 385 commands); 386 } 387 } 388 389 /* Grab the INIT header. */ 390 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 391 392 /* Tag the variable length parameters. */ 393 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 394 395 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 396 if (!new_asoc) 397 goto nomem; 398 399 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 400 sctp_scope(sctp_source(chunk)), 401 GFP_ATOMIC) < 0) 402 goto nomem_init; 403 404 /* The call, sctp_process_init(), can fail on memory allocation. */ 405 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 406 (sctp_init_chunk_t *)chunk->chunk_hdr, 407 GFP_ATOMIC)) 408 goto nomem_init; 409 410 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 411 412 /* If there are errors need to be reported for unknown parameters, 413 * make sure to reserve enough room in the INIT ACK for them. 414 */ 415 len = 0; 416 if (err_chunk) 417 len = ntohs(err_chunk->chunk_hdr->length) - 418 sizeof(sctp_chunkhdr_t); 419 420 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 421 if (!repl) 422 goto nomem_init; 423 424 /* If there are errors need to be reported for unknown parameters, 425 * include them in the outgoing INIT ACK as "Unrecognized parameter" 426 * parameter. 427 */ 428 if (err_chunk) { 429 /* Get the "Unrecognized parameter" parameter(s) out of the 430 * ERROR chunk generated by sctp_verify_init(). Since the 431 * error cause code for "unknown parameter" and the 432 * "Unrecognized parameter" type is the same, we can 433 * construct the parameters in INIT ACK by copying the 434 * ERROR causes over. 435 */ 436 unk_param = (sctp_unrecognized_param_t *) 437 ((__u8 *)(err_chunk->chunk_hdr) + 438 sizeof(sctp_chunkhdr_t)); 439 /* Replace the cause code with the "Unrecognized parameter" 440 * parameter type. 441 */ 442 sctp_addto_chunk(repl, len, unk_param); 443 sctp_chunk_free(err_chunk); 444 } 445 446 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 447 448 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 449 450 /* 451 * Note: After sending out INIT ACK with the State Cookie parameter, 452 * "Z" MUST NOT allocate any resources, nor keep any states for the 453 * new association. Otherwise, "Z" will be vulnerable to resource 454 * attacks. 455 */ 456 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 457 458 return SCTP_DISPOSITION_DELETE_TCB; 459 460 nomem_init: 461 sctp_association_free(new_asoc); 462 nomem: 463 if (err_chunk) 464 sctp_chunk_free(err_chunk); 465 return SCTP_DISPOSITION_NOMEM; 466 } 467 468 /* 469 * Respond to a normal INIT ACK chunk. 470 * We are the side that is initiating the association. 471 * 472 * Section: 5.1 Normal Establishment of an Association, C 473 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 474 * timer and leave COOKIE-WAIT state. "A" shall then send the State 475 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 476 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 477 * 478 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 479 * DATA chunks, but it MUST be the first chunk in the packet and 480 * until the COOKIE ACK is returned the sender MUST NOT send any 481 * other packets to the peer. 482 * 483 * Verification Tag: 3.3.3 484 * If the value of the Initiate Tag in a received INIT ACK chunk is 485 * found to be 0, the receiver MUST treat it as an error and close the 486 * association by transmitting an ABORT. 487 * 488 * Inputs 489 * (endpoint, asoc, chunk) 490 * 491 * Outputs 492 * (asoc, reply_msg, msg_up, timers, counters) 493 * 494 * The return value is the disposition of the chunk. 495 */ 496 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 497 const struct sctp_endpoint *ep, 498 const struct sctp_association *asoc, 499 const sctp_subtype_t type, 500 void *arg, 501 sctp_cmd_seq_t *commands) 502 { 503 struct sctp_chunk *chunk = arg; 504 sctp_init_chunk_t *initchunk; 505 struct sctp_chunk *err_chunk; 506 struct sctp_packet *packet; 507 508 if (!sctp_vtag_verify(chunk, asoc)) 509 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 510 511 /* 6.10 Bundling 512 * An endpoint MUST NOT bundle INIT, INIT ACK or 513 * SHUTDOWN COMPLETE with any other chunks. 514 */ 515 if (!chunk->singleton) 516 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 517 518 /* Make sure that the INIT-ACK chunk has a valid length */ 519 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 520 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 521 commands); 522 /* Grab the INIT header. */ 523 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 524 525 /* Verify the INIT chunk before processing it. */ 526 err_chunk = NULL; 527 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 528 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 529 &err_chunk)) { 530 531 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 532 533 /* This chunk contains fatal error. It is to be discarded. 534 * Send an ABORT, with causes. If there are no causes, 535 * then there wasn't enough memory. Just terminate 536 * the association. 537 */ 538 if (err_chunk) { 539 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 540 (__u8 *)(err_chunk->chunk_hdr) + 541 sizeof(sctp_chunkhdr_t), 542 ntohs(err_chunk->chunk_hdr->length) - 543 sizeof(sctp_chunkhdr_t)); 544 545 sctp_chunk_free(err_chunk); 546 547 if (packet) { 548 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 549 SCTP_PACKET(packet)); 550 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 551 error = SCTP_ERROR_INV_PARAM; 552 } 553 } 554 555 /* SCTP-AUTH, Section 6.3: 556 * It should be noted that if the receiver wants to tear 557 * down an association in an authenticated way only, the 558 * handling of malformed packets should not result in 559 * tearing down the association. 560 * 561 * This means that if we only want to abort associations 562 * in an authenticated way (i.e AUTH+ABORT), then we 563 * can't destroy this association just because the packet 564 * was malformed. 565 */ 566 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 567 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 568 569 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 570 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 571 asoc, chunk->transport); 572 } 573 574 /* Tag the variable length parameters. Note that we never 575 * convert the parameters in an INIT chunk. 576 */ 577 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 578 579 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 580 581 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 582 SCTP_PEER_INIT(initchunk)); 583 584 /* Reset init error count upon receipt of INIT-ACK. */ 585 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 586 587 /* 5.1 C) "A" shall stop the T1-init timer and leave 588 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 589 * timer, and enter the COOKIE-ECHOED state. 590 */ 591 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 592 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 595 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 596 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 597 598 /* SCTP-AUTH: genereate the assocition shared keys so that 599 * we can potentially signe the COOKIE-ECHO. 600 */ 601 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 602 603 /* 5.1 C) "A" shall then send the State Cookie received in the 604 * INIT ACK chunk in a COOKIE ECHO chunk, ... 605 */ 606 /* If there is any errors to report, send the ERROR chunk generated 607 * for unknown parameters as well. 608 */ 609 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 610 SCTP_CHUNK(err_chunk)); 611 612 return SCTP_DISPOSITION_CONSUME; 613 } 614 615 /* 616 * Respond to a normal COOKIE ECHO chunk. 617 * We are the side that is being asked for an association. 618 * 619 * Section: 5.1 Normal Establishment of an Association, D 620 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 621 * with a COOKIE ACK chunk after building a TCB and moving to 622 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 623 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 624 * chunk MUST be the first chunk in the packet. 625 * 626 * IMPLEMENTATION NOTE: An implementation may choose to send the 627 * Communication Up notification to the SCTP user upon reception 628 * of a valid COOKIE ECHO chunk. 629 * 630 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 631 * D) Rules for packet carrying a COOKIE ECHO 632 * 633 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 634 * Initial Tag received in the INIT ACK. 635 * 636 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 637 * 638 * Inputs 639 * (endpoint, asoc, chunk) 640 * 641 * Outputs 642 * (asoc, reply_msg, msg_up, timers, counters) 643 * 644 * The return value is the disposition of the chunk. 645 */ 646 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 647 const struct sctp_endpoint *ep, 648 const struct sctp_association *asoc, 649 const sctp_subtype_t type, void *arg, 650 sctp_cmd_seq_t *commands) 651 { 652 struct sctp_chunk *chunk = arg; 653 struct sctp_association *new_asoc; 654 sctp_init_chunk_t *peer_init; 655 struct sctp_chunk *repl; 656 struct sctp_ulpevent *ev, *ai_ev = NULL; 657 int error = 0; 658 struct sctp_chunk *err_chk_p; 659 struct sock *sk; 660 661 /* If the packet is an OOTB packet which is temporarily on the 662 * control endpoint, respond with an ABORT. 663 */ 664 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 665 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 666 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 667 } 668 669 /* Make sure that the COOKIE_ECHO chunk has a valid length. 670 * In this case, we check that we have enough for at least a 671 * chunk header. More detailed verification is done 672 * in sctp_unpack_cookie(). 673 */ 674 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 676 677 /* If the endpoint is not listening or if the number of associations 678 * on the TCP-style socket exceed the max backlog, respond with an 679 * ABORT. 680 */ 681 sk = ep->base.sk; 682 if (!sctp_sstate(sk, LISTENING) || 683 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 684 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 685 686 /* "Decode" the chunk. We have no optional parameters so we 687 * are in good shape. 688 */ 689 chunk->subh.cookie_hdr = 690 (struct sctp_signed_cookie *)chunk->skb->data; 691 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 692 sizeof(sctp_chunkhdr_t))) 693 goto nomem; 694 695 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 696 * "Z" will reply with a COOKIE ACK chunk after building a TCB 697 * and moving to the ESTABLISHED state. 698 */ 699 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 700 &err_chk_p); 701 702 /* FIXME: 703 * If the re-build failed, what is the proper error path 704 * from here? 705 * 706 * [We should abort the association. --piggy] 707 */ 708 if (!new_asoc) { 709 /* FIXME: Several errors are possible. A bad cookie should 710 * be silently discarded, but think about logging it too. 711 */ 712 switch (error) { 713 case -SCTP_IERROR_NOMEM: 714 goto nomem; 715 716 case -SCTP_IERROR_STALE_COOKIE: 717 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 718 err_chk_p); 719 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 720 721 case -SCTP_IERROR_BAD_SIG: 722 default: 723 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 724 } 725 } 726 727 728 /* Delay state machine commands until later. 729 * 730 * Re-build the bind address for the association is done in 731 * the sctp_unpack_cookie() already. 732 */ 733 /* This is a brand-new association, so these are not yet side 734 * effects--it is safe to run them here. 735 */ 736 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 737 738 if (!sctp_process_init(new_asoc, chunk, 739 &chunk->subh.cookie_hdr->c.peer_addr, 740 peer_init, GFP_ATOMIC)) 741 goto nomem_init; 742 743 /* SCTP-AUTH: Now that we've populate required fields in 744 * sctp_process_init, set up the assocaition shared keys as 745 * necessary so that we can potentially authenticate the ACK 746 */ 747 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 748 if (error) 749 goto nomem_init; 750 751 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 752 * is supposed to be authenticated and we have to do delayed 753 * authentication. We've just recreated the association using 754 * the information in the cookie and now it's much easier to 755 * do the authentication. 756 */ 757 if (chunk->auth_chunk) { 758 struct sctp_chunk auth; 759 sctp_ierror_t ret; 760 761 /* Make sure that we and the peer are AUTH capable */ 762 if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) { 763 sctp_association_free(new_asoc); 764 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 765 } 766 767 /* set-up our fake chunk so that we can process it */ 768 auth.skb = chunk->auth_chunk; 769 auth.asoc = chunk->asoc; 770 auth.sctp_hdr = chunk->sctp_hdr; 771 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 772 sizeof(sctp_chunkhdr_t)); 773 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 774 auth.transport = chunk->transport; 775 776 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 777 if (ret != SCTP_IERROR_NO_ERROR) { 778 sctp_association_free(new_asoc); 779 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 780 } 781 } 782 783 repl = sctp_make_cookie_ack(new_asoc, chunk); 784 if (!repl) 785 goto nomem_init; 786 787 /* RFC 2960 5.1 Normal Establishment of an Association 788 * 789 * D) IMPLEMENTATION NOTE: An implementation may choose to 790 * send the Communication Up notification to the SCTP user 791 * upon reception of a valid COOKIE ECHO chunk. 792 */ 793 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 794 new_asoc->c.sinit_num_ostreams, 795 new_asoc->c.sinit_max_instreams, 796 NULL, GFP_ATOMIC); 797 if (!ev) 798 goto nomem_ev; 799 800 /* Sockets API Draft Section 5.3.1.6 801 * When a peer sends a Adaptation Layer Indication parameter , SCTP 802 * delivers this notification to inform the application that of the 803 * peers requested adaptation layer. 804 */ 805 if (new_asoc->peer.adaptation_ind) { 806 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 807 GFP_ATOMIC); 808 if (!ai_ev) 809 goto nomem_aiev; 810 } 811 812 /* Add all the state machine commands now since we've created 813 * everything. This way we don't introduce memory corruptions 814 * during side-effect processing and correclty count established 815 * associations. 816 */ 817 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 818 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 819 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 820 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 821 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 822 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 823 824 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 825 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 826 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 827 828 /* This will send the COOKIE ACK */ 829 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 830 831 /* Queue the ASSOC_CHANGE event */ 832 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 833 834 /* Send up the Adaptation Layer Indication event */ 835 if (ai_ev) 836 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 837 SCTP_ULPEVENT(ai_ev)); 838 839 return SCTP_DISPOSITION_CONSUME; 840 841 nomem_aiev: 842 sctp_ulpevent_free(ev); 843 nomem_ev: 844 sctp_chunk_free(repl); 845 nomem_init: 846 sctp_association_free(new_asoc); 847 nomem: 848 return SCTP_DISPOSITION_NOMEM; 849 } 850 851 /* 852 * Respond to a normal COOKIE ACK chunk. 853 * We are the side that is being asked for an association. 854 * 855 * RFC 2960 5.1 Normal Establishment of an Association 856 * 857 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 858 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 859 * timer. It may also notify its ULP about the successful 860 * establishment of the association with a Communication Up 861 * notification (see Section 10). 862 * 863 * Verification Tag: 864 * Inputs 865 * (endpoint, asoc, chunk) 866 * 867 * Outputs 868 * (asoc, reply_msg, msg_up, timers, counters) 869 * 870 * The return value is the disposition of the chunk. 871 */ 872 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 873 const struct sctp_endpoint *ep, 874 const struct sctp_association *asoc, 875 const sctp_subtype_t type, void *arg, 876 sctp_cmd_seq_t *commands) 877 { 878 struct sctp_chunk *chunk = arg; 879 struct sctp_ulpevent *ev; 880 881 if (!sctp_vtag_verify(chunk, asoc)) 882 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 883 884 /* Verify that the chunk length for the COOKIE-ACK is OK. 885 * If we don't do this, any bundled chunks may be junked. 886 */ 887 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 888 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 889 commands); 890 891 /* Reset init error count upon receipt of COOKIE-ACK, 892 * to avoid problems with the managemement of this 893 * counter in stale cookie situations when a transition back 894 * from the COOKIE-ECHOED state to the COOKIE-WAIT 895 * state is performed. 896 */ 897 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 898 899 /* RFC 2960 5.1 Normal Establishment of an Association 900 * 901 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 902 * from the COOKIE-ECHOED state to the ESTABLISHED state, 903 * stopping the T1-cookie timer. 904 */ 905 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 906 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 907 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 908 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 909 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 910 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 911 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 912 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 913 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 914 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 915 916 /* It may also notify its ULP about the successful 917 * establishment of the association with a Communication Up 918 * notification (see Section 10). 919 */ 920 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 921 0, asoc->c.sinit_num_ostreams, 922 asoc->c.sinit_max_instreams, 923 NULL, GFP_ATOMIC); 924 925 if (!ev) 926 goto nomem; 927 928 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 929 930 /* Sockets API Draft Section 5.3.1.6 931 * When a peer sends a Adaptation Layer Indication parameter , SCTP 932 * delivers this notification to inform the application that of the 933 * peers requested adaptation layer. 934 */ 935 if (asoc->peer.adaptation_ind) { 936 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 937 if (!ev) 938 goto nomem; 939 940 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 941 SCTP_ULPEVENT(ev)); 942 } 943 944 return SCTP_DISPOSITION_CONSUME; 945 nomem: 946 return SCTP_DISPOSITION_NOMEM; 947 } 948 949 /* Generate and sendout a heartbeat packet. */ 950 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 951 const struct sctp_association *asoc, 952 const sctp_subtype_t type, 953 void *arg, 954 sctp_cmd_seq_t *commands) 955 { 956 struct sctp_transport *transport = (struct sctp_transport *) arg; 957 struct sctp_chunk *reply; 958 959 /* Send a heartbeat to our peer. */ 960 reply = sctp_make_heartbeat(asoc, transport); 961 if (!reply) 962 return SCTP_DISPOSITION_NOMEM; 963 964 /* Set rto_pending indicating that an RTT measurement 965 * is started with this heartbeat chunk. 966 */ 967 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 968 SCTP_TRANSPORT(transport)); 969 970 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 971 return SCTP_DISPOSITION_CONSUME; 972 } 973 974 /* Generate a HEARTBEAT packet on the given transport. */ 975 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 976 const struct sctp_endpoint *ep, 977 const struct sctp_association *asoc, 978 const sctp_subtype_t type, 979 void *arg, 980 sctp_cmd_seq_t *commands) 981 { 982 struct sctp_transport *transport = (struct sctp_transport *) arg; 983 984 if (asoc->overall_error_count >= asoc->max_retrans) { 985 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 986 SCTP_ERROR(ETIMEDOUT)); 987 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 988 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 989 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 990 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 991 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 992 return SCTP_DISPOSITION_DELETE_TCB; 993 } 994 995 /* Section 3.3.5. 996 * The Sender-specific Heartbeat Info field should normally include 997 * information about the sender's current time when this HEARTBEAT 998 * chunk is sent and the destination transport address to which this 999 * HEARTBEAT is sent (see Section 8.3). 1000 */ 1001 1002 if (transport->param_flags & SPP_HB_ENABLE) { 1003 if (SCTP_DISPOSITION_NOMEM == 1004 sctp_sf_heartbeat(ep, asoc, type, arg, 1005 commands)) 1006 return SCTP_DISPOSITION_NOMEM; 1007 1008 /* Set transport error counter and association error counter 1009 * when sending heartbeat. 1010 */ 1011 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1012 SCTP_TRANSPORT(transport)); 1013 } 1014 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1015 SCTP_TRANSPORT(transport)); 1016 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1017 SCTP_TRANSPORT(transport)); 1018 1019 return SCTP_DISPOSITION_CONSUME; 1020 } 1021 1022 /* 1023 * Process an heartbeat request. 1024 * 1025 * Section: 8.3 Path Heartbeat 1026 * The receiver of the HEARTBEAT should immediately respond with a 1027 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1028 * from the received HEARTBEAT chunk. 1029 * 1030 * Verification Tag: 8.5 Verification Tag [Normal verification] 1031 * When receiving an SCTP packet, the endpoint MUST ensure that the 1032 * value in the Verification Tag field of the received SCTP packet 1033 * matches its own Tag. If the received Verification Tag value does not 1034 * match the receiver's own tag value, the receiver shall silently 1035 * discard the packet and shall not process it any further except for 1036 * those cases listed in Section 8.5.1 below. 1037 * 1038 * Inputs 1039 * (endpoint, asoc, chunk) 1040 * 1041 * Outputs 1042 * (asoc, reply_msg, msg_up, timers, counters) 1043 * 1044 * The return value is the disposition of the chunk. 1045 */ 1046 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1047 const struct sctp_endpoint *ep, 1048 const struct sctp_association *asoc, 1049 const sctp_subtype_t type, 1050 void *arg, 1051 sctp_cmd_seq_t *commands) 1052 { 1053 sctp_paramhdr_t *param_hdr; 1054 struct sctp_chunk *chunk = arg; 1055 struct sctp_chunk *reply; 1056 size_t paylen = 0; 1057 1058 if (!sctp_vtag_verify(chunk, asoc)) 1059 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1060 1061 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1062 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1063 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1064 commands); 1065 1066 /* 8.3 The receiver of the HEARTBEAT should immediately 1067 * respond with a HEARTBEAT ACK that contains the Heartbeat 1068 * Information field copied from the received HEARTBEAT chunk. 1069 */ 1070 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1071 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr; 1072 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1073 1074 if (ntohs(param_hdr->length) > paylen) 1075 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1076 param_hdr, commands); 1077 1078 if (!pskb_pull(chunk->skb, paylen)) 1079 goto nomem; 1080 1081 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1082 if (!reply) 1083 goto nomem; 1084 1085 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1086 return SCTP_DISPOSITION_CONSUME; 1087 1088 nomem: 1089 return SCTP_DISPOSITION_NOMEM; 1090 } 1091 1092 /* 1093 * Process the returning HEARTBEAT ACK. 1094 * 1095 * Section: 8.3 Path Heartbeat 1096 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1097 * should clear the error counter of the destination transport 1098 * address to which the HEARTBEAT was sent, and mark the destination 1099 * transport address as active if it is not so marked. The endpoint may 1100 * optionally report to the upper layer when an inactive destination 1101 * address is marked as active due to the reception of the latest 1102 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1103 * clear the association overall error count as well (as defined 1104 * in section 8.1). 1105 * 1106 * The receiver of the HEARTBEAT ACK should also perform an RTT 1107 * measurement for that destination transport address using the time 1108 * value carried in the HEARTBEAT ACK chunk. 1109 * 1110 * Verification Tag: 8.5 Verification Tag [Normal verification] 1111 * 1112 * Inputs 1113 * (endpoint, asoc, chunk) 1114 * 1115 * Outputs 1116 * (asoc, reply_msg, msg_up, timers, counters) 1117 * 1118 * The return value is the disposition of the chunk. 1119 */ 1120 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1121 const struct sctp_endpoint *ep, 1122 const struct sctp_association *asoc, 1123 const sctp_subtype_t type, 1124 void *arg, 1125 sctp_cmd_seq_t *commands) 1126 { 1127 struct sctp_chunk *chunk = arg; 1128 union sctp_addr from_addr; 1129 struct sctp_transport *link; 1130 sctp_sender_hb_info_t *hbinfo; 1131 unsigned long max_interval; 1132 1133 if (!sctp_vtag_verify(chunk, asoc)) 1134 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1135 1136 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1137 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1138 sizeof(sctp_sender_hb_info_t))) 1139 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1140 commands); 1141 1142 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1143 /* Make sure that the length of the parameter is what we expect */ 1144 if (ntohs(hbinfo->param_hdr.length) != 1145 sizeof(sctp_sender_hb_info_t)) { 1146 return SCTP_DISPOSITION_DISCARD; 1147 } 1148 1149 from_addr = hbinfo->daddr; 1150 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1151 1152 /* This should never happen, but lets log it if so. */ 1153 if (unlikely(!link)) { 1154 if (from_addr.sa.sa_family == AF_INET6) { 1155 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1156 __func__, 1157 asoc, 1158 &from_addr.v6.sin6_addr); 1159 } else { 1160 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1161 __func__, 1162 asoc, 1163 &from_addr.v4.sin_addr.s_addr); 1164 } 1165 return SCTP_DISPOSITION_DISCARD; 1166 } 1167 1168 /* Validate the 64-bit random nonce. */ 1169 if (hbinfo->hb_nonce != link->hb_nonce) 1170 return SCTP_DISPOSITION_DISCARD; 1171 1172 max_interval = link->hbinterval + link->rto; 1173 1174 /* Check if the timestamp looks valid. */ 1175 if (time_after(hbinfo->sent_at, jiffies) || 1176 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1177 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1178 "for transport:%p\n", __func__, link); 1179 1180 return SCTP_DISPOSITION_DISCARD; 1181 } 1182 1183 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1184 * the HEARTBEAT should clear the error counter of the 1185 * destination transport address to which the HEARTBEAT was 1186 * sent and mark the destination transport address as active if 1187 * it is not so marked. 1188 */ 1189 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1190 1191 return SCTP_DISPOSITION_CONSUME; 1192 } 1193 1194 /* Helper function to send out an abort for the restart 1195 * condition. 1196 */ 1197 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1198 struct sctp_chunk *init, 1199 sctp_cmd_seq_t *commands) 1200 { 1201 int len; 1202 struct sctp_packet *pkt; 1203 union sctp_addr_param *addrparm; 1204 struct sctp_errhdr *errhdr; 1205 struct sctp_endpoint *ep; 1206 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1207 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1208 1209 /* Build the error on the stack. We are way to malloc crazy 1210 * throughout the code today. 1211 */ 1212 errhdr = (struct sctp_errhdr *)buffer; 1213 addrparm = (union sctp_addr_param *)errhdr->variable; 1214 1215 /* Copy into a parm format. */ 1216 len = af->to_addr_param(ssa, addrparm); 1217 len += sizeof(sctp_errhdr_t); 1218 1219 errhdr->cause = SCTP_ERROR_RESTART; 1220 errhdr->length = htons(len); 1221 1222 /* Assign to the control socket. */ 1223 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1224 1225 /* Association is NULL since this may be a restart attack and we 1226 * want to send back the attacker's vtag. 1227 */ 1228 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1229 1230 if (!pkt) 1231 goto out; 1232 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1233 1234 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1235 1236 /* Discard the rest of the inbound packet. */ 1237 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1238 1239 out: 1240 /* Even if there is no memory, treat as a failure so 1241 * the packet will get dropped. 1242 */ 1243 return 0; 1244 } 1245 1246 static bool list_has_sctp_addr(const struct list_head *list, 1247 union sctp_addr *ipaddr) 1248 { 1249 struct sctp_transport *addr; 1250 1251 list_for_each_entry(addr, list, transports) { 1252 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1253 return true; 1254 } 1255 1256 return false; 1257 } 1258 /* A restart is occurring, check to make sure no new addresses 1259 * are being added as we may be under a takeover attack. 1260 */ 1261 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1262 const struct sctp_association *asoc, 1263 struct sctp_chunk *init, 1264 sctp_cmd_seq_t *commands) 1265 { 1266 struct net *net = sock_net(new_asoc->base.sk); 1267 struct sctp_transport *new_addr; 1268 int ret = 1; 1269 1270 /* Implementor's Guide - Section 5.2.2 1271 * ... 1272 * Before responding the endpoint MUST check to see if the 1273 * unexpected INIT adds new addresses to the association. If new 1274 * addresses are added to the association, the endpoint MUST respond 1275 * with an ABORT.. 1276 */ 1277 1278 /* Search through all current addresses and make sure 1279 * we aren't adding any new ones. 1280 */ 1281 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1282 transports) { 1283 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1284 &new_addr->ipaddr)) { 1285 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1286 commands); 1287 ret = 0; 1288 break; 1289 } 1290 } 1291 1292 /* Return success if all addresses were found. */ 1293 return ret; 1294 } 1295 1296 /* Populate the verification/tie tags based on overlapping INIT 1297 * scenario. 1298 * 1299 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1300 */ 1301 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1302 const struct sctp_association *asoc) 1303 { 1304 switch (asoc->state) { 1305 1306 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1307 1308 case SCTP_STATE_COOKIE_WAIT: 1309 new_asoc->c.my_vtag = asoc->c.my_vtag; 1310 new_asoc->c.my_ttag = asoc->c.my_vtag; 1311 new_asoc->c.peer_ttag = 0; 1312 break; 1313 1314 case SCTP_STATE_COOKIE_ECHOED: 1315 new_asoc->c.my_vtag = asoc->c.my_vtag; 1316 new_asoc->c.my_ttag = asoc->c.my_vtag; 1317 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1318 break; 1319 1320 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1321 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1322 */ 1323 default: 1324 new_asoc->c.my_ttag = asoc->c.my_vtag; 1325 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1326 break; 1327 } 1328 1329 /* Other parameters for the endpoint SHOULD be copied from the 1330 * existing parameters of the association (e.g. number of 1331 * outbound streams) into the INIT ACK and cookie. 1332 */ 1333 new_asoc->rwnd = asoc->rwnd; 1334 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1335 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1336 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1337 } 1338 1339 /* 1340 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1341 * handling action. 1342 * 1343 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1344 * 1345 * Returns value representing action to be taken. These action values 1346 * correspond to Action/Description values in RFC 2960, Table 2. 1347 */ 1348 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1349 const struct sctp_association *asoc) 1350 { 1351 /* In this case, the peer may have restarted. */ 1352 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1353 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1354 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1355 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1356 return 'A'; 1357 1358 /* Collision case B. */ 1359 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1360 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1361 (0 == asoc->c.peer_vtag))) { 1362 return 'B'; 1363 } 1364 1365 /* Collision case D. */ 1366 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1367 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1368 return 'D'; 1369 1370 /* Collision case C. */ 1371 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1372 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1373 (0 == new_asoc->c.my_ttag) && 1374 (0 == new_asoc->c.peer_ttag)) 1375 return 'C'; 1376 1377 /* No match to any of the special cases; discard this packet. */ 1378 return 'E'; 1379 } 1380 1381 /* Common helper routine for both duplicate and simulataneous INIT 1382 * chunk handling. 1383 */ 1384 static sctp_disposition_t sctp_sf_do_unexpected_init( 1385 struct net *net, 1386 const struct sctp_endpoint *ep, 1387 const struct sctp_association *asoc, 1388 const sctp_subtype_t type, 1389 void *arg, sctp_cmd_seq_t *commands) 1390 { 1391 sctp_disposition_t retval; 1392 struct sctp_chunk *chunk = arg; 1393 struct sctp_chunk *repl; 1394 struct sctp_association *new_asoc; 1395 struct sctp_chunk *err_chunk; 1396 struct sctp_packet *packet; 1397 sctp_unrecognized_param_t *unk_param; 1398 int len; 1399 1400 /* 6.10 Bundling 1401 * An endpoint MUST NOT bundle INIT, INIT ACK or 1402 * SHUTDOWN COMPLETE with any other chunks. 1403 * 1404 * IG Section 2.11.2 1405 * Furthermore, we require that the receiver of an INIT chunk MUST 1406 * enforce these rules by silently discarding an arriving packet 1407 * with an INIT chunk that is bundled with other chunks. 1408 */ 1409 if (!chunk->singleton) 1410 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1411 1412 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1413 * Tag. 1414 */ 1415 if (chunk->sctp_hdr->vtag != 0) 1416 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1417 1418 /* Make sure that the INIT chunk has a valid length. 1419 * In this case, we generate a protocol violation since we have 1420 * an association established. 1421 */ 1422 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1423 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1424 commands); 1425 /* Grab the INIT header. */ 1426 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1427 1428 /* Tag the variable length parameters. */ 1429 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1430 1431 /* Verify the INIT chunk before processing it. */ 1432 err_chunk = NULL; 1433 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1434 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1435 &err_chunk)) { 1436 /* This chunk contains fatal error. It is to be discarded. 1437 * Send an ABORT, with causes if there is any. 1438 */ 1439 if (err_chunk) { 1440 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1441 (__u8 *)(err_chunk->chunk_hdr) + 1442 sizeof(sctp_chunkhdr_t), 1443 ntohs(err_chunk->chunk_hdr->length) - 1444 sizeof(sctp_chunkhdr_t)); 1445 1446 if (packet) { 1447 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1448 SCTP_PACKET(packet)); 1449 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1450 retval = SCTP_DISPOSITION_CONSUME; 1451 } else { 1452 retval = SCTP_DISPOSITION_NOMEM; 1453 } 1454 goto cleanup; 1455 } else { 1456 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1457 commands); 1458 } 1459 } 1460 1461 /* 1462 * Other parameters for the endpoint SHOULD be copied from the 1463 * existing parameters of the association (e.g. number of 1464 * outbound streams) into the INIT ACK and cookie. 1465 * FIXME: We are copying parameters from the endpoint not the 1466 * association. 1467 */ 1468 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1469 if (!new_asoc) 1470 goto nomem; 1471 1472 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1473 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1474 goto nomem; 1475 1476 /* In the outbound INIT ACK the endpoint MUST copy its current 1477 * Verification Tag and Peers Verification tag into a reserved 1478 * place (local tie-tag and per tie-tag) within the state cookie. 1479 */ 1480 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1481 (sctp_init_chunk_t *)chunk->chunk_hdr, 1482 GFP_ATOMIC)) 1483 goto nomem; 1484 1485 /* Make sure no new addresses are being added during the 1486 * restart. Do not do this check for COOKIE-WAIT state, 1487 * since there are no peer addresses to check against. 1488 * Upon return an ABORT will have been sent if needed. 1489 */ 1490 if (!sctp_state(asoc, COOKIE_WAIT)) { 1491 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1492 commands)) { 1493 retval = SCTP_DISPOSITION_CONSUME; 1494 goto nomem_retval; 1495 } 1496 } 1497 1498 sctp_tietags_populate(new_asoc, asoc); 1499 1500 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1501 1502 /* If there are errors need to be reported for unknown parameters, 1503 * make sure to reserve enough room in the INIT ACK for them. 1504 */ 1505 len = 0; 1506 if (err_chunk) { 1507 len = ntohs(err_chunk->chunk_hdr->length) - 1508 sizeof(sctp_chunkhdr_t); 1509 } 1510 1511 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1512 if (!repl) 1513 goto nomem; 1514 1515 /* If there are errors need to be reported for unknown parameters, 1516 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1517 * parameter. 1518 */ 1519 if (err_chunk) { 1520 /* Get the "Unrecognized parameter" parameter(s) out of the 1521 * ERROR chunk generated by sctp_verify_init(). Since the 1522 * error cause code for "unknown parameter" and the 1523 * "Unrecognized parameter" type is the same, we can 1524 * construct the parameters in INIT ACK by copying the 1525 * ERROR causes over. 1526 */ 1527 unk_param = (sctp_unrecognized_param_t *) 1528 ((__u8 *)(err_chunk->chunk_hdr) + 1529 sizeof(sctp_chunkhdr_t)); 1530 /* Replace the cause code with the "Unrecognized parameter" 1531 * parameter type. 1532 */ 1533 sctp_addto_chunk(repl, len, unk_param); 1534 } 1535 1536 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1537 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1538 1539 /* 1540 * Note: After sending out INIT ACK with the State Cookie parameter, 1541 * "Z" MUST NOT allocate any resources for this new association. 1542 * Otherwise, "Z" will be vulnerable to resource attacks. 1543 */ 1544 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1545 retval = SCTP_DISPOSITION_CONSUME; 1546 1547 return retval; 1548 1549 nomem: 1550 retval = SCTP_DISPOSITION_NOMEM; 1551 nomem_retval: 1552 if (new_asoc) 1553 sctp_association_free(new_asoc); 1554 cleanup: 1555 if (err_chunk) 1556 sctp_chunk_free(err_chunk); 1557 return retval; 1558 } 1559 1560 /* 1561 * Handle simultaneous INIT. 1562 * This means we started an INIT and then we got an INIT request from 1563 * our peer. 1564 * 1565 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1566 * This usually indicates an initialization collision, i.e., each 1567 * endpoint is attempting, at about the same time, to establish an 1568 * association with the other endpoint. 1569 * 1570 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1571 * endpoint MUST respond with an INIT ACK using the same parameters it 1572 * sent in its original INIT chunk (including its Verification Tag, 1573 * unchanged). These original parameters are combined with those from the 1574 * newly received INIT chunk. The endpoint shall also generate a State 1575 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1576 * INIT to calculate the State Cookie. 1577 * 1578 * After that, the endpoint MUST NOT change its state, the T1-init 1579 * timer shall be left running and the corresponding TCB MUST NOT be 1580 * destroyed. The normal procedures for handling State Cookies when 1581 * a TCB exists will resolve the duplicate INITs to a single association. 1582 * 1583 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1584 * its Tie-Tags with the Tag information of itself and its peer (see 1585 * section 5.2.2 for a description of the Tie-Tags). 1586 * 1587 * Verification Tag: Not explicit, but an INIT can not have a valid 1588 * verification tag, so we skip the check. 1589 * 1590 * Inputs 1591 * (endpoint, asoc, chunk) 1592 * 1593 * Outputs 1594 * (asoc, reply_msg, msg_up, timers, counters) 1595 * 1596 * The return value is the disposition of the chunk. 1597 */ 1598 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1599 const struct sctp_endpoint *ep, 1600 const struct sctp_association *asoc, 1601 const sctp_subtype_t type, 1602 void *arg, 1603 sctp_cmd_seq_t *commands) 1604 { 1605 /* Call helper to do the real work for both simulataneous and 1606 * duplicate INIT chunk handling. 1607 */ 1608 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1609 } 1610 1611 /* 1612 * Handle duplicated INIT messages. These are usually delayed 1613 * restransmissions. 1614 * 1615 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1616 * COOKIE-ECHOED and COOKIE-WAIT 1617 * 1618 * Unless otherwise stated, upon reception of an unexpected INIT for 1619 * this association, the endpoint shall generate an INIT ACK with a 1620 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1621 * current Verification Tag and peer's Verification Tag into a reserved 1622 * place within the state cookie. We shall refer to these locations as 1623 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1624 * containing this INIT ACK MUST carry a Verification Tag value equal to 1625 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1626 * MUST contain a new Initiation Tag (randomly generated see Section 1627 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1628 * existing parameters of the association (e.g. number of outbound 1629 * streams) into the INIT ACK and cookie. 1630 * 1631 * After sending out the INIT ACK, the endpoint shall take no further 1632 * actions, i.e., the existing association, including its current state, 1633 * and the corresponding TCB MUST NOT be changed. 1634 * 1635 * Note: Only when a TCB exists and the association is not in a COOKIE- 1636 * WAIT state are the Tie-Tags populated. For a normal association INIT 1637 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1638 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1639 * State Cookie are populated as specified in section 5.2.1. 1640 * 1641 * Verification Tag: Not specified, but an INIT has no way of knowing 1642 * what the verification tag could be, so we ignore it. 1643 * 1644 * Inputs 1645 * (endpoint, asoc, chunk) 1646 * 1647 * Outputs 1648 * (asoc, reply_msg, msg_up, timers, counters) 1649 * 1650 * The return value is the disposition of the chunk. 1651 */ 1652 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1653 const struct sctp_endpoint *ep, 1654 const struct sctp_association *asoc, 1655 const sctp_subtype_t type, 1656 void *arg, 1657 sctp_cmd_seq_t *commands) 1658 { 1659 /* Call helper to do the real work for both simulataneous and 1660 * duplicate INIT chunk handling. 1661 */ 1662 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1663 } 1664 1665 1666 /* 1667 * Unexpected INIT-ACK handler. 1668 * 1669 * Section 5.2.3 1670 * If an INIT ACK received by an endpoint in any state other than the 1671 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1672 * An unexpected INIT ACK usually indicates the processing of an old or 1673 * duplicated INIT chunk. 1674 */ 1675 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1676 const struct sctp_endpoint *ep, 1677 const struct sctp_association *asoc, 1678 const sctp_subtype_t type, 1679 void *arg, sctp_cmd_seq_t *commands) 1680 { 1681 /* Per the above section, we'll discard the chunk if we have an 1682 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1683 */ 1684 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1685 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1686 else 1687 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1688 } 1689 1690 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1691 * 1692 * Section 5.2.4 1693 * A) In this case, the peer may have restarted. 1694 */ 1695 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1696 const struct sctp_endpoint *ep, 1697 const struct sctp_association *asoc, 1698 struct sctp_chunk *chunk, 1699 sctp_cmd_seq_t *commands, 1700 struct sctp_association *new_asoc) 1701 { 1702 sctp_init_chunk_t *peer_init; 1703 struct sctp_ulpevent *ev; 1704 struct sctp_chunk *repl; 1705 struct sctp_chunk *err; 1706 sctp_disposition_t disposition; 1707 1708 /* new_asoc is a brand-new association, so these are not yet 1709 * side effects--it is safe to run them here. 1710 */ 1711 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1712 1713 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1714 GFP_ATOMIC)) 1715 goto nomem; 1716 1717 /* Make sure no new addresses are being added during the 1718 * restart. Though this is a pretty complicated attack 1719 * since you'd have to get inside the cookie. 1720 */ 1721 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1722 return SCTP_DISPOSITION_CONSUME; 1723 } 1724 1725 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1726 * the peer has restarted (Action A), it MUST NOT setup a new 1727 * association but instead resend the SHUTDOWN ACK and send an ERROR 1728 * chunk with a "Cookie Received while Shutting Down" error cause to 1729 * its peer. 1730 */ 1731 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1732 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1733 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1734 chunk, commands); 1735 if (SCTP_DISPOSITION_NOMEM == disposition) 1736 goto nomem; 1737 1738 err = sctp_make_op_error(asoc, chunk, 1739 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1740 NULL, 0, 0); 1741 if (err) 1742 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1743 SCTP_CHUNK(err)); 1744 1745 return SCTP_DISPOSITION_CONSUME; 1746 } 1747 1748 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1749 * data. Consider the optional choice of resending of this data. 1750 */ 1751 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1752 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1753 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1754 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1755 1756 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1757 * and ASCONF-ACK cache. 1758 */ 1759 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1760 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1761 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1762 1763 repl = sctp_make_cookie_ack(new_asoc, chunk); 1764 if (!repl) 1765 goto nomem; 1766 1767 /* Report association restart to upper layer. */ 1768 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1769 new_asoc->c.sinit_num_ostreams, 1770 new_asoc->c.sinit_max_instreams, 1771 NULL, GFP_ATOMIC); 1772 if (!ev) 1773 goto nomem_ev; 1774 1775 /* Update the content of current association. */ 1776 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1777 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1778 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1779 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1780 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1781 return SCTP_DISPOSITION_CONSUME; 1782 1783 nomem_ev: 1784 sctp_chunk_free(repl); 1785 nomem: 1786 return SCTP_DISPOSITION_NOMEM; 1787 } 1788 1789 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1790 * 1791 * Section 5.2.4 1792 * B) In this case, both sides may be attempting to start an association 1793 * at about the same time but the peer endpoint started its INIT 1794 * after responding to the local endpoint's INIT 1795 */ 1796 /* This case represents an initialization collision. */ 1797 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1798 const struct sctp_endpoint *ep, 1799 const struct sctp_association *asoc, 1800 struct sctp_chunk *chunk, 1801 sctp_cmd_seq_t *commands, 1802 struct sctp_association *new_asoc) 1803 { 1804 sctp_init_chunk_t *peer_init; 1805 struct sctp_chunk *repl; 1806 1807 /* new_asoc is a brand-new association, so these are not yet 1808 * side effects--it is safe to run them here. 1809 */ 1810 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1811 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1812 GFP_ATOMIC)) 1813 goto nomem; 1814 1815 /* Update the content of current association. */ 1816 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1817 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1818 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1819 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1820 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1821 1822 repl = sctp_make_cookie_ack(new_asoc, chunk); 1823 if (!repl) 1824 goto nomem; 1825 1826 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1827 1828 /* RFC 2960 5.1 Normal Establishment of an Association 1829 * 1830 * D) IMPLEMENTATION NOTE: An implementation may choose to 1831 * send the Communication Up notification to the SCTP user 1832 * upon reception of a valid COOKIE ECHO chunk. 1833 * 1834 * Sadly, this needs to be implemented as a side-effect, because 1835 * we are not guaranteed to have set the association id of the real 1836 * association and so these notifications need to be delayed until 1837 * the association id is allocated. 1838 */ 1839 1840 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1841 1842 /* Sockets API Draft Section 5.3.1.6 1843 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1844 * delivers this notification to inform the application that of the 1845 * peers requested adaptation layer. 1846 * 1847 * This also needs to be done as a side effect for the same reason as 1848 * above. 1849 */ 1850 if (asoc->peer.adaptation_ind) 1851 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1852 1853 return SCTP_DISPOSITION_CONSUME; 1854 1855 nomem: 1856 return SCTP_DISPOSITION_NOMEM; 1857 } 1858 1859 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1860 * 1861 * Section 5.2.4 1862 * C) In this case, the local endpoint's cookie has arrived late. 1863 * Before it arrived, the local endpoint sent an INIT and received an 1864 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1865 * but a new tag of its own. 1866 */ 1867 /* This case represents an initialization collision. */ 1868 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1869 const struct sctp_endpoint *ep, 1870 const struct sctp_association *asoc, 1871 struct sctp_chunk *chunk, 1872 sctp_cmd_seq_t *commands, 1873 struct sctp_association *new_asoc) 1874 { 1875 /* The cookie should be silently discarded. 1876 * The endpoint SHOULD NOT change states and should leave 1877 * any timers running. 1878 */ 1879 return SCTP_DISPOSITION_DISCARD; 1880 } 1881 1882 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1883 * 1884 * Section 5.2.4 1885 * 1886 * D) When both local and remote tags match the endpoint should always 1887 * enter the ESTABLISHED state, if it has not already done so. 1888 */ 1889 /* This case represents an initialization collision. */ 1890 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1891 const struct sctp_endpoint *ep, 1892 const struct sctp_association *asoc, 1893 struct sctp_chunk *chunk, 1894 sctp_cmd_seq_t *commands, 1895 struct sctp_association *new_asoc) 1896 { 1897 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1898 struct sctp_chunk *repl; 1899 1900 /* Clarification from Implementor's Guide: 1901 * D) When both local and remote tags match the endpoint should 1902 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1903 * It should stop any cookie timer that may be running and send 1904 * a COOKIE ACK. 1905 */ 1906 1907 /* Don't accidentally move back into established state. */ 1908 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1909 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1910 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1911 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1912 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1913 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1914 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1915 SCTP_NULL()); 1916 1917 /* RFC 2960 5.1 Normal Establishment of an Association 1918 * 1919 * D) IMPLEMENTATION NOTE: An implementation may choose 1920 * to send the Communication Up notification to the 1921 * SCTP user upon reception of a valid COOKIE 1922 * ECHO chunk. 1923 */ 1924 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1925 SCTP_COMM_UP, 0, 1926 asoc->c.sinit_num_ostreams, 1927 asoc->c.sinit_max_instreams, 1928 NULL, GFP_ATOMIC); 1929 if (!ev) 1930 goto nomem; 1931 1932 /* Sockets API Draft Section 5.3.1.6 1933 * When a peer sends a Adaptation Layer Indication parameter, 1934 * SCTP delivers this notification to inform the application 1935 * that of the peers requested adaptation layer. 1936 */ 1937 if (asoc->peer.adaptation_ind) { 1938 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1939 GFP_ATOMIC); 1940 if (!ai_ev) 1941 goto nomem; 1942 1943 } 1944 } 1945 1946 repl = sctp_make_cookie_ack(new_asoc, chunk); 1947 if (!repl) 1948 goto nomem; 1949 1950 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1951 1952 if (ev) 1953 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1954 SCTP_ULPEVENT(ev)); 1955 if (ai_ev) 1956 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1957 SCTP_ULPEVENT(ai_ev)); 1958 1959 return SCTP_DISPOSITION_CONSUME; 1960 1961 nomem: 1962 if (ai_ev) 1963 sctp_ulpevent_free(ai_ev); 1964 if (ev) 1965 sctp_ulpevent_free(ev); 1966 return SCTP_DISPOSITION_NOMEM; 1967 } 1968 1969 /* 1970 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1971 * chunk was retransmitted and then delayed in the network. 1972 * 1973 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1974 * 1975 * Verification Tag: None. Do cookie validation. 1976 * 1977 * Inputs 1978 * (endpoint, asoc, chunk) 1979 * 1980 * Outputs 1981 * (asoc, reply_msg, msg_up, timers, counters) 1982 * 1983 * The return value is the disposition of the chunk. 1984 */ 1985 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 1986 const struct sctp_endpoint *ep, 1987 const struct sctp_association *asoc, 1988 const sctp_subtype_t type, 1989 void *arg, 1990 sctp_cmd_seq_t *commands) 1991 { 1992 sctp_disposition_t retval; 1993 struct sctp_chunk *chunk = arg; 1994 struct sctp_association *new_asoc; 1995 int error = 0; 1996 char action; 1997 struct sctp_chunk *err_chk_p; 1998 1999 /* Make sure that the chunk has a valid length from the protocol 2000 * perspective. In this case check to make sure we have at least 2001 * enough for the chunk header. Cookie length verification is 2002 * done later. 2003 */ 2004 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2005 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2006 commands); 2007 2008 /* "Decode" the chunk. We have no optional parameters so we 2009 * are in good shape. 2010 */ 2011 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2012 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2013 sizeof(sctp_chunkhdr_t))) 2014 goto nomem; 2015 2016 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2017 * of a duplicate COOKIE ECHO match the Verification Tags of the 2018 * current association, consider the State Cookie valid even if 2019 * the lifespan is exceeded. 2020 */ 2021 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2022 &err_chk_p); 2023 2024 /* FIXME: 2025 * If the re-build failed, what is the proper error path 2026 * from here? 2027 * 2028 * [We should abort the association. --piggy] 2029 */ 2030 if (!new_asoc) { 2031 /* FIXME: Several errors are possible. A bad cookie should 2032 * be silently discarded, but think about logging it too. 2033 */ 2034 switch (error) { 2035 case -SCTP_IERROR_NOMEM: 2036 goto nomem; 2037 2038 case -SCTP_IERROR_STALE_COOKIE: 2039 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2040 err_chk_p); 2041 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2042 case -SCTP_IERROR_BAD_SIG: 2043 default: 2044 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2045 } 2046 } 2047 2048 /* Compare the tie_tag in cookie with the verification tag of 2049 * current association. 2050 */ 2051 action = sctp_tietags_compare(new_asoc, asoc); 2052 2053 switch (action) { 2054 case 'A': /* Association restart. */ 2055 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2056 new_asoc); 2057 break; 2058 2059 case 'B': /* Collision case B. */ 2060 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2061 new_asoc); 2062 break; 2063 2064 case 'C': /* Collision case C. */ 2065 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2066 new_asoc); 2067 break; 2068 2069 case 'D': /* Collision case D. */ 2070 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2071 new_asoc); 2072 break; 2073 2074 default: /* Discard packet for all others. */ 2075 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2076 break; 2077 } 2078 2079 /* Delete the tempory new association. */ 2080 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2081 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2082 2083 /* Restore association pointer to provide SCTP command interpeter 2084 * with a valid context in case it needs to manipulate 2085 * the queues */ 2086 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2087 SCTP_ASOC((struct sctp_association *)asoc)); 2088 2089 return retval; 2090 2091 nomem: 2092 return SCTP_DISPOSITION_NOMEM; 2093 } 2094 2095 /* 2096 * Process an ABORT. (SHUTDOWN-PENDING state) 2097 * 2098 * See sctp_sf_do_9_1_abort(). 2099 */ 2100 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2101 struct net *net, 2102 const struct sctp_endpoint *ep, 2103 const struct sctp_association *asoc, 2104 const sctp_subtype_t type, 2105 void *arg, 2106 sctp_cmd_seq_t *commands) 2107 { 2108 struct sctp_chunk *chunk = arg; 2109 2110 if (!sctp_vtag_verify_either(chunk, asoc)) 2111 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2112 2113 /* Make sure that the ABORT chunk has a valid length. 2114 * Since this is an ABORT chunk, we have to discard it 2115 * because of the following text: 2116 * RFC 2960, Section 3.3.7 2117 * If an endpoint receives an ABORT with a format error or for an 2118 * association that doesn't exist, it MUST silently discard it. 2119 * Because the length is "invalid", we can't really discard just 2120 * as we do not know its true length. So, to be safe, discard the 2121 * packet. 2122 */ 2123 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2124 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2125 2126 /* ADD-IP: Special case for ABORT chunks 2127 * F4) One special consideration is that ABORT Chunks arriving 2128 * destined to the IP address being deleted MUST be 2129 * ignored (see Section 5.3.1 for further details). 2130 */ 2131 if (SCTP_ADDR_DEL == 2132 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2133 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2134 2135 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2136 } 2137 2138 /* 2139 * Process an ABORT. (SHUTDOWN-SENT state) 2140 * 2141 * See sctp_sf_do_9_1_abort(). 2142 */ 2143 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2144 const struct sctp_endpoint *ep, 2145 const struct sctp_association *asoc, 2146 const sctp_subtype_t type, 2147 void *arg, 2148 sctp_cmd_seq_t *commands) 2149 { 2150 struct sctp_chunk *chunk = arg; 2151 2152 if (!sctp_vtag_verify_either(chunk, asoc)) 2153 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2154 2155 /* Make sure that the ABORT chunk has a valid length. 2156 * Since this is an ABORT chunk, we have to discard it 2157 * because of the following text: 2158 * RFC 2960, Section 3.3.7 2159 * If an endpoint receives an ABORT with a format error or for an 2160 * association that doesn't exist, it MUST silently discard it. 2161 * Because the length is "invalid", we can't really discard just 2162 * as we do not know its true length. So, to be safe, discard the 2163 * packet. 2164 */ 2165 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2166 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2167 2168 /* ADD-IP: Special case for ABORT chunks 2169 * F4) One special consideration is that ABORT Chunks arriving 2170 * destined to the IP address being deleted MUST be 2171 * ignored (see Section 5.3.1 for further details). 2172 */ 2173 if (SCTP_ADDR_DEL == 2174 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2175 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2176 2177 /* Stop the T2-shutdown timer. */ 2178 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2179 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2180 2181 /* Stop the T5-shutdown guard timer. */ 2182 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2183 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2184 2185 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2186 } 2187 2188 /* 2189 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2190 * 2191 * See sctp_sf_do_9_1_abort(). 2192 */ 2193 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2194 struct net *net, 2195 const struct sctp_endpoint *ep, 2196 const struct sctp_association *asoc, 2197 const sctp_subtype_t type, 2198 void *arg, 2199 sctp_cmd_seq_t *commands) 2200 { 2201 /* The same T2 timer, so we should be able to use 2202 * common function with the SHUTDOWN-SENT state. 2203 */ 2204 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2205 } 2206 2207 /* 2208 * Handle an Error received in COOKIE_ECHOED state. 2209 * 2210 * Only handle the error type of stale COOKIE Error, the other errors will 2211 * be ignored. 2212 * 2213 * Inputs 2214 * (endpoint, asoc, chunk) 2215 * 2216 * Outputs 2217 * (asoc, reply_msg, msg_up, timers, counters) 2218 * 2219 * The return value is the disposition of the chunk. 2220 */ 2221 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2222 const struct sctp_endpoint *ep, 2223 const struct sctp_association *asoc, 2224 const sctp_subtype_t type, 2225 void *arg, 2226 sctp_cmd_seq_t *commands) 2227 { 2228 struct sctp_chunk *chunk = arg; 2229 sctp_errhdr_t *err; 2230 2231 if (!sctp_vtag_verify(chunk, asoc)) 2232 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2233 2234 /* Make sure that the ERROR chunk has a valid length. 2235 * The parameter walking depends on this as well. 2236 */ 2237 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2238 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2239 commands); 2240 2241 /* Process the error here */ 2242 /* FUTURE FIXME: When PR-SCTP related and other optional 2243 * parms are emitted, this will have to change to handle multiple 2244 * errors. 2245 */ 2246 sctp_walk_errors(err, chunk->chunk_hdr) { 2247 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2248 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2249 arg, commands); 2250 } 2251 2252 /* It is possible to have malformed error causes, and that 2253 * will cause us to end the walk early. However, since 2254 * we are discarding the packet, there should be no adverse 2255 * affects. 2256 */ 2257 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2258 } 2259 2260 /* 2261 * Handle a Stale COOKIE Error 2262 * 2263 * Section: 5.2.6 Handle Stale COOKIE Error 2264 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2265 * one of the following three alternatives. 2266 * ... 2267 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2268 * Preservative parameter requesting an extension to the lifetime of 2269 * the State Cookie. When calculating the time extension, an 2270 * implementation SHOULD use the RTT information measured based on the 2271 * previous COOKIE ECHO / ERROR exchange, and should add no more 2272 * than 1 second beyond the measured RTT, due to long State Cookie 2273 * lifetimes making the endpoint more subject to a replay attack. 2274 * 2275 * Verification Tag: Not explicit, but safe to ignore. 2276 * 2277 * Inputs 2278 * (endpoint, asoc, chunk) 2279 * 2280 * Outputs 2281 * (asoc, reply_msg, msg_up, timers, counters) 2282 * 2283 * The return value is the disposition of the chunk. 2284 */ 2285 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2286 const struct sctp_endpoint *ep, 2287 const struct sctp_association *asoc, 2288 const sctp_subtype_t type, 2289 void *arg, 2290 sctp_cmd_seq_t *commands) 2291 { 2292 struct sctp_chunk *chunk = arg; 2293 time_t stale; 2294 sctp_cookie_preserve_param_t bht; 2295 sctp_errhdr_t *err; 2296 struct sctp_chunk *reply; 2297 struct sctp_bind_addr *bp; 2298 int attempts = asoc->init_err_counter + 1; 2299 2300 if (attempts > asoc->max_init_attempts) { 2301 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2302 SCTP_ERROR(ETIMEDOUT)); 2303 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2304 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2305 return SCTP_DISPOSITION_DELETE_TCB; 2306 } 2307 2308 err = (sctp_errhdr_t *)(chunk->skb->data); 2309 2310 /* When calculating the time extension, an implementation 2311 * SHOULD use the RTT information measured based on the 2312 * previous COOKIE ECHO / ERROR exchange, and should add no 2313 * more than 1 second beyond the measured RTT, due to long 2314 * State Cookie lifetimes making the endpoint more subject to 2315 * a replay attack. 2316 * Measure of Staleness's unit is usec. (1/1000000 sec) 2317 * Suggested Cookie Life-span Increment's unit is msec. 2318 * (1/1000 sec) 2319 * In general, if you use the suggested cookie life, the value 2320 * found in the field of measure of staleness should be doubled 2321 * to give ample time to retransmit the new cookie and thus 2322 * yield a higher probability of success on the reattempt. 2323 */ 2324 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2325 stale = (stale * 2) / 1000; 2326 2327 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2328 bht.param_hdr.length = htons(sizeof(bht)); 2329 bht.lifespan_increment = htonl(stale); 2330 2331 /* Build that new INIT chunk. */ 2332 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2333 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2334 if (!reply) 2335 goto nomem; 2336 2337 sctp_addto_chunk(reply, sizeof(bht), &bht); 2338 2339 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2340 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2341 2342 /* Stop pending T3-rtx and heartbeat timers */ 2343 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2344 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2345 2346 /* Delete non-primary peer ip addresses since we are transitioning 2347 * back to the COOKIE-WAIT state 2348 */ 2349 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2350 2351 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2352 * resend 2353 */ 2354 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2355 SCTP_TRANSPORT(asoc->peer.primary_path)); 2356 2357 /* Cast away the const modifier, as we want to just 2358 * rerun it through as a sideffect. 2359 */ 2360 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2361 2362 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2363 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2364 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2365 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2366 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2367 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2368 2369 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2370 2371 return SCTP_DISPOSITION_CONSUME; 2372 2373 nomem: 2374 return SCTP_DISPOSITION_NOMEM; 2375 } 2376 2377 /* 2378 * Process an ABORT. 2379 * 2380 * Section: 9.1 2381 * After checking the Verification Tag, the receiving endpoint shall 2382 * remove the association from its record, and shall report the 2383 * termination to its upper layer. 2384 * 2385 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2386 * B) Rules for packet carrying ABORT: 2387 * 2388 * - The endpoint shall always fill in the Verification Tag field of the 2389 * outbound packet with the destination endpoint's tag value if it 2390 * is known. 2391 * 2392 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2393 * MUST follow the procedure described in Section 8.4. 2394 * 2395 * - The receiver MUST accept the packet if the Verification Tag 2396 * matches either its own tag, OR the tag of its peer. Otherwise, the 2397 * receiver MUST silently discard the packet and take no further 2398 * action. 2399 * 2400 * Inputs 2401 * (endpoint, asoc, chunk) 2402 * 2403 * Outputs 2404 * (asoc, reply_msg, msg_up, timers, counters) 2405 * 2406 * The return value is the disposition of the chunk. 2407 */ 2408 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2409 const struct sctp_endpoint *ep, 2410 const struct sctp_association *asoc, 2411 const sctp_subtype_t type, 2412 void *arg, 2413 sctp_cmd_seq_t *commands) 2414 { 2415 struct sctp_chunk *chunk = arg; 2416 2417 if (!sctp_vtag_verify_either(chunk, asoc)) 2418 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2419 2420 /* Make sure that the ABORT chunk has a valid length. 2421 * Since this is an ABORT chunk, we have to discard it 2422 * because of the following text: 2423 * RFC 2960, Section 3.3.7 2424 * If an endpoint receives an ABORT with a format error or for an 2425 * association that doesn't exist, it MUST silently discard it. 2426 * Because the length is "invalid", we can't really discard just 2427 * as we do not know its true length. So, to be safe, discard the 2428 * packet. 2429 */ 2430 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2431 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2432 2433 /* ADD-IP: Special case for ABORT chunks 2434 * F4) One special consideration is that ABORT Chunks arriving 2435 * destined to the IP address being deleted MUST be 2436 * ignored (see Section 5.3.1 for further details). 2437 */ 2438 if (SCTP_ADDR_DEL == 2439 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2440 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2441 2442 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2443 } 2444 2445 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2446 const struct sctp_endpoint *ep, 2447 const struct sctp_association *asoc, 2448 const sctp_subtype_t type, 2449 void *arg, 2450 sctp_cmd_seq_t *commands) 2451 { 2452 struct sctp_chunk *chunk = arg; 2453 unsigned int len; 2454 __be16 error = SCTP_ERROR_NO_ERROR; 2455 2456 /* See if we have an error cause code in the chunk. */ 2457 len = ntohs(chunk->chunk_hdr->length); 2458 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2459 2460 sctp_errhdr_t *err; 2461 sctp_walk_errors(err, chunk->chunk_hdr); 2462 if ((void *)err != (void *)chunk->chunk_end) 2463 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2464 2465 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2466 } 2467 2468 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2469 /* ASSOC_FAILED will DELETE_TCB. */ 2470 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2471 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2472 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2473 2474 return SCTP_DISPOSITION_ABORT; 2475 } 2476 2477 /* 2478 * Process an ABORT. (COOKIE-WAIT state) 2479 * 2480 * See sctp_sf_do_9_1_abort() above. 2481 */ 2482 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2483 const struct sctp_endpoint *ep, 2484 const struct sctp_association *asoc, 2485 const sctp_subtype_t type, 2486 void *arg, 2487 sctp_cmd_seq_t *commands) 2488 { 2489 struct sctp_chunk *chunk = arg; 2490 unsigned int len; 2491 __be16 error = SCTP_ERROR_NO_ERROR; 2492 2493 if (!sctp_vtag_verify_either(chunk, asoc)) 2494 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2495 2496 /* Make sure that the ABORT chunk has a valid length. 2497 * Since this is an ABORT chunk, we have to discard it 2498 * because of the following text: 2499 * RFC 2960, Section 3.3.7 2500 * If an endpoint receives an ABORT with a format error or for an 2501 * association that doesn't exist, it MUST silently discard it. 2502 * Because the length is "invalid", we can't really discard just 2503 * as we do not know its true length. So, to be safe, discard the 2504 * packet. 2505 */ 2506 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2507 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2508 2509 /* See if we have an error cause code in the chunk. */ 2510 len = ntohs(chunk->chunk_hdr->length); 2511 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2512 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2513 2514 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2515 chunk->transport); 2516 } 2517 2518 /* 2519 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2520 */ 2521 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2522 const struct sctp_endpoint *ep, 2523 const struct sctp_association *asoc, 2524 const sctp_subtype_t type, 2525 void *arg, 2526 sctp_cmd_seq_t *commands) 2527 { 2528 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2529 ENOPROTOOPT, asoc, 2530 (struct sctp_transport *)arg); 2531 } 2532 2533 /* 2534 * Process an ABORT. (COOKIE-ECHOED state) 2535 */ 2536 sctp_disposition_t sctp_sf_cookie_echoed_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 /* There is a single T1 timer, so we should be able to use 2544 * common function with the COOKIE-WAIT state. 2545 */ 2546 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2547 } 2548 2549 /* 2550 * Stop T1 timer and abort association with "INIT failed". 2551 * 2552 * This is common code called by several sctp_sf_*_abort() functions above. 2553 */ 2554 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2555 sctp_cmd_seq_t *commands, 2556 __be16 error, int sk_err, 2557 const struct sctp_association *asoc, 2558 struct sctp_transport *transport) 2559 { 2560 pr_debug("%s: ABORT received (INIT)\n", __func__); 2561 2562 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2563 SCTP_STATE(SCTP_STATE_CLOSED)); 2564 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2565 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2566 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2567 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2568 /* CMD_INIT_FAILED will DELETE_TCB. */ 2569 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2570 SCTP_PERR(error)); 2571 2572 return SCTP_DISPOSITION_ABORT; 2573 } 2574 2575 /* 2576 * sctp_sf_do_9_2_shut 2577 * 2578 * Section: 9.2 2579 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2580 * - enter the SHUTDOWN-RECEIVED state, 2581 * 2582 * - stop accepting new data from its SCTP user 2583 * 2584 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2585 * that all its outstanding DATA chunks have been received by the 2586 * SHUTDOWN sender. 2587 * 2588 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2589 * send a SHUTDOWN in response to a ULP request. And should discard 2590 * subsequent SHUTDOWN chunks. 2591 * 2592 * If there are still outstanding DATA chunks left, the SHUTDOWN 2593 * receiver shall continue to follow normal data transmission 2594 * procedures defined in Section 6 until all outstanding DATA chunks 2595 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2596 * new data from its SCTP user. 2597 * 2598 * Verification Tag: 8.5 Verification Tag [Normal verification] 2599 * 2600 * Inputs 2601 * (endpoint, asoc, chunk) 2602 * 2603 * Outputs 2604 * (asoc, reply_msg, msg_up, timers, counters) 2605 * 2606 * The return value is the disposition of the chunk. 2607 */ 2608 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2609 const struct sctp_endpoint *ep, 2610 const struct sctp_association *asoc, 2611 const sctp_subtype_t type, 2612 void *arg, 2613 sctp_cmd_seq_t *commands) 2614 { 2615 struct sctp_chunk *chunk = arg; 2616 sctp_shutdownhdr_t *sdh; 2617 sctp_disposition_t disposition; 2618 struct sctp_ulpevent *ev; 2619 __u32 ctsn; 2620 2621 if (!sctp_vtag_verify(chunk, asoc)) 2622 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2623 2624 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2625 if (!sctp_chunk_length_valid(chunk, 2626 sizeof(struct sctp_shutdown_chunk_t))) 2627 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2628 commands); 2629 2630 /* Convert the elaborate header. */ 2631 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2632 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2633 chunk->subh.shutdown_hdr = sdh; 2634 ctsn = ntohl(sdh->cum_tsn_ack); 2635 2636 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2637 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2638 asoc->ctsn_ack_point); 2639 2640 return SCTP_DISPOSITION_DISCARD; 2641 } 2642 2643 /* If Cumulative TSN Ack beyond the max tsn currently 2644 * send, terminating the association and respond to the 2645 * sender with an ABORT. 2646 */ 2647 if (!TSN_lt(ctsn, asoc->next_tsn)) 2648 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2649 2650 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2651 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2652 * inform the application that it should cease sending data. 2653 */ 2654 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2655 if (!ev) { 2656 disposition = SCTP_DISPOSITION_NOMEM; 2657 goto out; 2658 } 2659 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2660 2661 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2662 * - enter the SHUTDOWN-RECEIVED state, 2663 * - stop accepting new data from its SCTP user 2664 * 2665 * [This is implicit in the new state.] 2666 */ 2667 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2668 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2669 disposition = SCTP_DISPOSITION_CONSUME; 2670 2671 if (sctp_outq_is_empty(&asoc->outqueue)) { 2672 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2673 arg, commands); 2674 } 2675 2676 if (SCTP_DISPOSITION_NOMEM == disposition) 2677 goto out; 2678 2679 /* - verify, by checking the Cumulative TSN Ack field of the 2680 * chunk, that all its outstanding DATA chunks have been 2681 * received by the SHUTDOWN sender. 2682 */ 2683 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2684 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2685 2686 out: 2687 return disposition; 2688 } 2689 2690 /* 2691 * sctp_sf_do_9_2_shut_ctsn 2692 * 2693 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2694 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2695 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2696 * MUST be processed. 2697 */ 2698 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2699 const struct sctp_endpoint *ep, 2700 const struct sctp_association *asoc, 2701 const sctp_subtype_t type, 2702 void *arg, 2703 sctp_cmd_seq_t *commands) 2704 { 2705 struct sctp_chunk *chunk = arg; 2706 sctp_shutdownhdr_t *sdh; 2707 __u32 ctsn; 2708 2709 if (!sctp_vtag_verify(chunk, asoc)) 2710 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2711 2712 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2713 if (!sctp_chunk_length_valid(chunk, 2714 sizeof(struct sctp_shutdown_chunk_t))) 2715 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2716 commands); 2717 2718 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2719 ctsn = ntohl(sdh->cum_tsn_ack); 2720 2721 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2722 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2723 asoc->ctsn_ack_point); 2724 2725 return SCTP_DISPOSITION_DISCARD; 2726 } 2727 2728 /* If Cumulative TSN Ack beyond the max tsn currently 2729 * send, terminating the association and respond to the 2730 * sender with an ABORT. 2731 */ 2732 if (!TSN_lt(ctsn, asoc->next_tsn)) 2733 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2734 2735 /* verify, by checking the Cumulative TSN Ack field of the 2736 * chunk, that all its outstanding DATA chunks have been 2737 * received by the SHUTDOWN sender. 2738 */ 2739 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2740 SCTP_BE32(sdh->cum_tsn_ack)); 2741 2742 return SCTP_DISPOSITION_CONSUME; 2743 } 2744 2745 /* RFC 2960 9.2 2746 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2747 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2748 * transport addresses (either in the IP addresses or in the INIT chunk) 2749 * that belong to this association, it should discard the INIT chunk and 2750 * retransmit the SHUTDOWN ACK chunk. 2751 */ 2752 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2753 const struct sctp_endpoint *ep, 2754 const struct sctp_association *asoc, 2755 const sctp_subtype_t type, 2756 void *arg, 2757 sctp_cmd_seq_t *commands) 2758 { 2759 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2760 struct sctp_chunk *reply; 2761 2762 /* Make sure that the chunk has a valid length */ 2763 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2764 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2765 commands); 2766 2767 /* Since we are not going to really process this INIT, there 2768 * is no point in verifying chunk boundries. Just generate 2769 * the SHUTDOWN ACK. 2770 */ 2771 reply = sctp_make_shutdown_ack(asoc, chunk); 2772 if (NULL == reply) 2773 goto nomem; 2774 2775 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2776 * the T2-SHUTDOWN timer. 2777 */ 2778 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2779 2780 /* and restart the T2-shutdown timer. */ 2781 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2782 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2783 2784 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2785 2786 return SCTP_DISPOSITION_CONSUME; 2787 nomem: 2788 return SCTP_DISPOSITION_NOMEM; 2789 } 2790 2791 /* 2792 * sctp_sf_do_ecn_cwr 2793 * 2794 * Section: Appendix A: Explicit Congestion Notification 2795 * 2796 * CWR: 2797 * 2798 * RFC 2481 details a specific bit for a sender to send in the header of 2799 * its next outbound TCP segment to indicate to its peer that it has 2800 * reduced its congestion window. This is termed the CWR bit. For 2801 * SCTP the same indication is made by including the CWR chunk. 2802 * This chunk contains one data element, i.e. the TSN number that 2803 * was sent in the ECNE chunk. This element represents the lowest 2804 * TSN number in the datagram that was originally marked with the 2805 * CE bit. 2806 * 2807 * Verification Tag: 8.5 Verification Tag [Normal verification] 2808 * Inputs 2809 * (endpoint, asoc, chunk) 2810 * 2811 * Outputs 2812 * (asoc, reply_msg, msg_up, timers, counters) 2813 * 2814 * The return value is the disposition of the chunk. 2815 */ 2816 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2817 const struct sctp_endpoint *ep, 2818 const struct sctp_association *asoc, 2819 const sctp_subtype_t type, 2820 void *arg, 2821 sctp_cmd_seq_t *commands) 2822 { 2823 sctp_cwrhdr_t *cwr; 2824 struct sctp_chunk *chunk = arg; 2825 u32 lowest_tsn; 2826 2827 if (!sctp_vtag_verify(chunk, asoc)) 2828 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2829 2830 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2831 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2832 commands); 2833 2834 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2835 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2836 2837 lowest_tsn = ntohl(cwr->lowest_tsn); 2838 2839 /* Does this CWR ack the last sent congestion notification? */ 2840 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2841 /* Stop sending ECNE. */ 2842 sctp_add_cmd_sf(commands, 2843 SCTP_CMD_ECN_CWR, 2844 SCTP_U32(lowest_tsn)); 2845 } 2846 return SCTP_DISPOSITION_CONSUME; 2847 } 2848 2849 /* 2850 * sctp_sf_do_ecne 2851 * 2852 * Section: Appendix A: Explicit Congestion Notification 2853 * 2854 * ECN-Echo 2855 * 2856 * RFC 2481 details a specific bit for a receiver to send back in its 2857 * TCP acknowledgements to notify the sender of the Congestion 2858 * Experienced (CE) bit having arrived from the network. For SCTP this 2859 * same indication is made by including the ECNE chunk. This chunk 2860 * contains one data element, i.e. the lowest TSN associated with the IP 2861 * datagram marked with the CE bit..... 2862 * 2863 * Verification Tag: 8.5 Verification Tag [Normal verification] 2864 * Inputs 2865 * (endpoint, asoc, chunk) 2866 * 2867 * Outputs 2868 * (asoc, reply_msg, msg_up, timers, counters) 2869 * 2870 * The return value is the disposition of the chunk. 2871 */ 2872 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2873 const struct sctp_endpoint *ep, 2874 const struct sctp_association *asoc, 2875 const sctp_subtype_t type, 2876 void *arg, 2877 sctp_cmd_seq_t *commands) 2878 { 2879 sctp_ecnehdr_t *ecne; 2880 struct sctp_chunk *chunk = arg; 2881 2882 if (!sctp_vtag_verify(chunk, asoc)) 2883 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2884 2885 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2886 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2887 commands); 2888 2889 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2890 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2891 2892 /* If this is a newer ECNE than the last CWR packet we sent out */ 2893 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2894 SCTP_U32(ntohl(ecne->lowest_tsn))); 2895 2896 return SCTP_DISPOSITION_CONSUME; 2897 } 2898 2899 /* 2900 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2901 * 2902 * The SCTP endpoint MUST always acknowledge the reception of each valid 2903 * DATA chunk. 2904 * 2905 * The guidelines on delayed acknowledgement algorithm specified in 2906 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2907 * acknowledgement SHOULD be generated for at least every second packet 2908 * (not every second DATA chunk) received, and SHOULD be generated within 2909 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2910 * situations it may be beneficial for an SCTP transmitter to be more 2911 * conservative than the algorithms detailed in this document allow. 2912 * However, an SCTP transmitter MUST NOT be more aggressive than the 2913 * following algorithms allow. 2914 * 2915 * A SCTP receiver MUST NOT generate more than one SACK for every 2916 * incoming packet, other than to update the offered window as the 2917 * receiving application consumes new data. 2918 * 2919 * Verification Tag: 8.5 Verification Tag [Normal verification] 2920 * 2921 * Inputs 2922 * (endpoint, asoc, chunk) 2923 * 2924 * Outputs 2925 * (asoc, reply_msg, msg_up, timers, counters) 2926 * 2927 * The return value is the disposition of the chunk. 2928 */ 2929 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2930 const struct sctp_endpoint *ep, 2931 const struct sctp_association *asoc, 2932 const sctp_subtype_t type, 2933 void *arg, 2934 sctp_cmd_seq_t *commands) 2935 { 2936 struct sctp_chunk *chunk = arg; 2937 sctp_arg_t force = SCTP_NOFORCE(); 2938 int error; 2939 2940 if (!sctp_vtag_verify(chunk, asoc)) { 2941 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2942 SCTP_NULL()); 2943 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2944 } 2945 2946 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2947 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2948 commands); 2949 2950 error = sctp_eat_data(asoc, chunk, commands); 2951 switch (error) { 2952 case SCTP_IERROR_NO_ERROR: 2953 break; 2954 case SCTP_IERROR_HIGH_TSN: 2955 case SCTP_IERROR_BAD_STREAM: 2956 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2957 goto discard_noforce; 2958 case SCTP_IERROR_DUP_TSN: 2959 case SCTP_IERROR_IGNORE_TSN: 2960 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2961 goto discard_force; 2962 case SCTP_IERROR_NO_DATA: 2963 goto consume; 2964 case SCTP_IERROR_PROTO_VIOLATION: 2965 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 2966 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2967 default: 2968 BUG(); 2969 } 2970 2971 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2972 force = SCTP_FORCE(); 2973 2974 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 2975 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2976 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2977 } 2978 2979 /* If this is the last chunk in a packet, we need to count it 2980 * toward sack generation. Note that we need to SACK every 2981 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2982 * THEM. We elect to NOT generate SACK's if the chunk fails 2983 * the verification tag test. 2984 * 2985 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2986 * 2987 * The SCTP endpoint MUST always acknowledge the reception of 2988 * each valid DATA chunk. 2989 * 2990 * The guidelines on delayed acknowledgement algorithm 2991 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2992 * Specifically, an acknowledgement SHOULD be generated for at 2993 * least every second packet (not every second DATA chunk) 2994 * received, and SHOULD be generated within 200 ms of the 2995 * arrival of any unacknowledged DATA chunk. In some 2996 * situations it may be beneficial for an SCTP transmitter to 2997 * be more conservative than the algorithms detailed in this 2998 * document allow. However, an SCTP transmitter MUST NOT be 2999 * more aggressive than the following algorithms allow. 3000 */ 3001 if (chunk->end_of_packet) 3002 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3003 3004 return SCTP_DISPOSITION_CONSUME; 3005 3006 discard_force: 3007 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3008 * 3009 * When a packet arrives with duplicate DATA chunk(s) and with 3010 * no new DATA chunk(s), the endpoint MUST immediately send a 3011 * SACK with no delay. If a packet arrives with duplicate 3012 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3013 * MAY immediately send a SACK. Normally receipt of duplicate 3014 * DATA chunks will occur when the original SACK chunk was lost 3015 * and the peer's RTO has expired. The duplicate TSN number(s) 3016 * SHOULD be reported in the SACK as duplicate. 3017 */ 3018 /* In our case, we split the MAY SACK advice up whether or not 3019 * the last chunk is a duplicate.' 3020 */ 3021 if (chunk->end_of_packet) 3022 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3023 return SCTP_DISPOSITION_DISCARD; 3024 3025 discard_noforce: 3026 if (chunk->end_of_packet) 3027 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3028 3029 return SCTP_DISPOSITION_DISCARD; 3030 consume: 3031 return SCTP_DISPOSITION_CONSUME; 3032 3033 } 3034 3035 /* 3036 * sctp_sf_eat_data_fast_4_4 3037 * 3038 * Section: 4 (4) 3039 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3040 * DATA chunks without delay. 3041 * 3042 * Verification Tag: 8.5 Verification Tag [Normal verification] 3043 * Inputs 3044 * (endpoint, asoc, chunk) 3045 * 3046 * Outputs 3047 * (asoc, reply_msg, msg_up, timers, counters) 3048 * 3049 * The return value is the disposition of the chunk. 3050 */ 3051 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3052 const struct sctp_endpoint *ep, 3053 const struct sctp_association *asoc, 3054 const sctp_subtype_t type, 3055 void *arg, 3056 sctp_cmd_seq_t *commands) 3057 { 3058 struct sctp_chunk *chunk = arg; 3059 int error; 3060 3061 if (!sctp_vtag_verify(chunk, asoc)) { 3062 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3063 SCTP_NULL()); 3064 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3065 } 3066 3067 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3068 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3069 commands); 3070 3071 error = sctp_eat_data(asoc, chunk, commands); 3072 switch (error) { 3073 case SCTP_IERROR_NO_ERROR: 3074 case SCTP_IERROR_HIGH_TSN: 3075 case SCTP_IERROR_DUP_TSN: 3076 case SCTP_IERROR_IGNORE_TSN: 3077 case SCTP_IERROR_BAD_STREAM: 3078 break; 3079 case SCTP_IERROR_NO_DATA: 3080 goto consume; 3081 case SCTP_IERROR_PROTO_VIOLATION: 3082 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3083 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3084 default: 3085 BUG(); 3086 } 3087 3088 /* Go a head and force a SACK, since we are shutting down. */ 3089 3090 /* Implementor's Guide. 3091 * 3092 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3093 * respond to each received packet containing one or more DATA chunk(s) 3094 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3095 */ 3096 if (chunk->end_of_packet) { 3097 /* We must delay the chunk creation since the cumulative 3098 * TSN has not been updated yet. 3099 */ 3100 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3101 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3102 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3103 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3104 } 3105 3106 consume: 3107 return SCTP_DISPOSITION_CONSUME; 3108 } 3109 3110 /* 3111 * Section: 6.2 Processing a Received SACK 3112 * D) Any time a SACK arrives, the endpoint performs the following: 3113 * 3114 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3115 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3116 * increasing, a SACK whose Cumulative TSN Ack is less than the 3117 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3118 * 3119 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3120 * of bytes still outstanding after processing the Cumulative TSN Ack 3121 * and the Gap Ack Blocks. 3122 * 3123 * iii) If the SACK is missing a TSN that was previously 3124 * acknowledged via a Gap Ack Block (e.g., the data receiver 3125 * reneged on the data), then mark the corresponding DATA chunk 3126 * as available for retransmit: Mark it as missing for fast 3127 * retransmit as described in Section 7.2.4 and if no retransmit 3128 * timer is running for the destination address to which the DATA 3129 * chunk was originally transmitted, then T3-rtx is started for 3130 * that destination address. 3131 * 3132 * Verification Tag: 8.5 Verification Tag [Normal verification] 3133 * 3134 * Inputs 3135 * (endpoint, asoc, chunk) 3136 * 3137 * Outputs 3138 * (asoc, reply_msg, msg_up, timers, counters) 3139 * 3140 * The return value is the disposition of the chunk. 3141 */ 3142 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3143 const struct sctp_endpoint *ep, 3144 const struct sctp_association *asoc, 3145 const sctp_subtype_t type, 3146 void *arg, 3147 sctp_cmd_seq_t *commands) 3148 { 3149 struct sctp_chunk *chunk = arg; 3150 sctp_sackhdr_t *sackh; 3151 __u32 ctsn; 3152 3153 if (!sctp_vtag_verify(chunk, asoc)) 3154 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3155 3156 /* Make sure that the SACK chunk has a valid length. */ 3157 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3158 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3159 commands); 3160 3161 /* Pull the SACK chunk from the data buffer */ 3162 sackh = sctp_sm_pull_sack(chunk); 3163 /* Was this a bogus SACK? */ 3164 if (!sackh) 3165 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3166 chunk->subh.sack_hdr = sackh; 3167 ctsn = ntohl(sackh->cum_tsn_ack); 3168 3169 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3170 * Ack Point, then drop the SACK. Since Cumulative TSN 3171 * Ack is monotonically increasing, a SACK whose 3172 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3173 * Point indicates an out-of-order SACK. 3174 */ 3175 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3176 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3177 asoc->ctsn_ack_point); 3178 3179 return SCTP_DISPOSITION_DISCARD; 3180 } 3181 3182 /* If Cumulative TSN Ack beyond the max tsn currently 3183 * send, terminating the association and respond to the 3184 * sender with an ABORT. 3185 */ 3186 if (!TSN_lt(ctsn, asoc->next_tsn)) 3187 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3188 3189 /* Return this SACK for further processing. */ 3190 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3191 3192 /* Note: We do the rest of the work on the PROCESS_SACK 3193 * sideeffect. 3194 */ 3195 return SCTP_DISPOSITION_CONSUME; 3196 } 3197 3198 /* 3199 * Generate an ABORT in response to a packet. 3200 * 3201 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3202 * 3203 * 8) The receiver should respond to the sender of the OOTB packet with 3204 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3205 * MUST fill in the Verification Tag field of the outbound packet 3206 * with the value found in the Verification Tag field of the OOTB 3207 * packet and set the T-bit in the Chunk Flags to indicate that the 3208 * Verification Tag is reflected. After sending this ABORT, the 3209 * receiver of the OOTB packet shall discard the OOTB packet and take 3210 * no further action. 3211 * 3212 * Verification Tag: 3213 * 3214 * The return value is the disposition of the chunk. 3215 */ 3216 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3217 const struct sctp_endpoint *ep, 3218 const struct sctp_association *asoc, 3219 const sctp_subtype_t type, 3220 void *arg, 3221 sctp_cmd_seq_t *commands) 3222 { 3223 struct sctp_packet *packet = NULL; 3224 struct sctp_chunk *chunk = arg; 3225 struct sctp_chunk *abort; 3226 3227 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3228 3229 if (packet) { 3230 /* Make an ABORT. The T bit will be set if the asoc 3231 * is NULL. 3232 */ 3233 abort = sctp_make_abort(asoc, chunk, 0); 3234 if (!abort) { 3235 sctp_ootb_pkt_free(packet); 3236 return SCTP_DISPOSITION_NOMEM; 3237 } 3238 3239 /* Reflect vtag if T-Bit is set */ 3240 if (sctp_test_T_bit(abort)) 3241 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3242 3243 /* Set the skb to the belonging sock for accounting. */ 3244 abort->skb->sk = ep->base.sk; 3245 3246 sctp_packet_append_chunk(packet, abort); 3247 3248 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3249 SCTP_PACKET(packet)); 3250 3251 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3252 3253 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3254 return SCTP_DISPOSITION_CONSUME; 3255 } 3256 3257 return SCTP_DISPOSITION_NOMEM; 3258 } 3259 3260 /* 3261 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3262 * event as ULP notification for each cause included in the chunk. 3263 * 3264 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3265 * 3266 * The return value is the disposition of the chunk. 3267 */ 3268 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3269 const struct sctp_endpoint *ep, 3270 const struct sctp_association *asoc, 3271 const sctp_subtype_t type, 3272 void *arg, 3273 sctp_cmd_seq_t *commands) 3274 { 3275 struct sctp_chunk *chunk = arg; 3276 sctp_errhdr_t *err; 3277 3278 if (!sctp_vtag_verify(chunk, asoc)) 3279 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3280 3281 /* Make sure that the ERROR chunk has a valid length. */ 3282 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3283 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3284 commands); 3285 sctp_walk_errors(err, chunk->chunk_hdr); 3286 if ((void *)err != (void *)chunk->chunk_end) 3287 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3288 (void *)err, commands); 3289 3290 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3291 SCTP_CHUNK(chunk)); 3292 3293 return SCTP_DISPOSITION_CONSUME; 3294 } 3295 3296 /* 3297 * Process an inbound SHUTDOWN ACK. 3298 * 3299 * From Section 9.2: 3300 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3301 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3302 * peer, and remove all record of the association. 3303 * 3304 * The return value is the disposition. 3305 */ 3306 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3307 const struct sctp_endpoint *ep, 3308 const struct sctp_association *asoc, 3309 const sctp_subtype_t type, 3310 void *arg, 3311 sctp_cmd_seq_t *commands) 3312 { 3313 struct sctp_chunk *chunk = arg; 3314 struct sctp_chunk *reply; 3315 struct sctp_ulpevent *ev; 3316 3317 if (!sctp_vtag_verify(chunk, asoc)) 3318 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3319 3320 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3321 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3322 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3323 commands); 3324 /* 10.2 H) SHUTDOWN COMPLETE notification 3325 * 3326 * When SCTP completes the shutdown procedures (section 9.2) this 3327 * notification is passed to the upper layer. 3328 */ 3329 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3330 0, 0, 0, NULL, GFP_ATOMIC); 3331 if (!ev) 3332 goto nomem; 3333 3334 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3335 reply = sctp_make_shutdown_complete(asoc, chunk); 3336 if (!reply) 3337 goto nomem_chunk; 3338 3339 /* Do all the commands now (after allocation), so that we 3340 * have consistent state if memory allocation failes 3341 */ 3342 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3343 3344 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3345 * stop the T2-shutdown timer, 3346 */ 3347 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3348 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3349 3350 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3351 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3352 3353 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3354 SCTP_STATE(SCTP_STATE_CLOSED)); 3355 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3356 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3357 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3358 3359 /* ...and remove all record of the association. */ 3360 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3361 return SCTP_DISPOSITION_DELETE_TCB; 3362 3363 nomem_chunk: 3364 sctp_ulpevent_free(ev); 3365 nomem: 3366 return SCTP_DISPOSITION_NOMEM; 3367 } 3368 3369 /* 3370 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3371 * 3372 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3373 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3374 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3375 * packet must fill in the Verification Tag field of the outbound 3376 * packet with the Verification Tag received in the SHUTDOWN ACK and 3377 * set the T-bit in the Chunk Flags to indicate that the Verification 3378 * Tag is reflected. 3379 * 3380 * 8) The receiver should respond to the sender of the OOTB packet with 3381 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3382 * MUST fill in the Verification Tag field of the outbound packet 3383 * with the value found in the Verification Tag field of the OOTB 3384 * packet and set the T-bit in the Chunk Flags to indicate that the 3385 * Verification Tag is reflected. After sending this ABORT, the 3386 * receiver of the OOTB packet shall discard the OOTB packet and take 3387 * no further action. 3388 */ 3389 sctp_disposition_t sctp_sf_ootb(struct net *net, 3390 const struct sctp_endpoint *ep, 3391 const struct sctp_association *asoc, 3392 const sctp_subtype_t type, 3393 void *arg, 3394 sctp_cmd_seq_t *commands) 3395 { 3396 struct sctp_chunk *chunk = arg; 3397 struct sk_buff *skb = chunk->skb; 3398 sctp_chunkhdr_t *ch; 3399 sctp_errhdr_t *err; 3400 __u8 *ch_end; 3401 int ootb_shut_ack = 0; 3402 int ootb_cookie_ack = 0; 3403 3404 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3405 3406 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3407 do { 3408 /* Report violation if the chunk is less then minimal */ 3409 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3410 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3411 commands); 3412 3413 /* Now that we know we at least have a chunk header, 3414 * do things that are type appropriate. 3415 */ 3416 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3417 ootb_shut_ack = 1; 3418 3419 /* RFC 2960, Section 3.3.7 3420 * Moreover, under any circumstances, an endpoint that 3421 * receives an ABORT MUST NOT respond to that ABORT by 3422 * sending an ABORT of its own. 3423 */ 3424 if (SCTP_CID_ABORT == ch->type) 3425 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3426 3427 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3428 * or a COOKIE ACK the SCTP Packet should be silently 3429 * discarded. 3430 */ 3431 3432 if (SCTP_CID_COOKIE_ACK == ch->type) 3433 ootb_cookie_ack = 1; 3434 3435 if (SCTP_CID_ERROR == ch->type) { 3436 sctp_walk_errors(err, ch) { 3437 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3438 ootb_cookie_ack = 1; 3439 break; 3440 } 3441 } 3442 } 3443 3444 /* Report violation if chunk len overflows */ 3445 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3446 if (ch_end > skb_tail_pointer(skb)) 3447 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3448 commands); 3449 3450 ch = (sctp_chunkhdr_t *) ch_end; 3451 } while (ch_end < skb_tail_pointer(skb)); 3452 3453 if (ootb_shut_ack) 3454 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3455 else if (ootb_cookie_ack) 3456 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3457 else 3458 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3459 } 3460 3461 /* 3462 * Handle an "Out of the blue" SHUTDOWN ACK. 3463 * 3464 * Section: 8.4 5, sctpimpguide 2.41. 3465 * 3466 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3467 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3468 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3469 * packet must fill in the Verification Tag field of the outbound 3470 * packet with the Verification Tag received in the SHUTDOWN ACK and 3471 * set the T-bit in the Chunk Flags to indicate that the Verification 3472 * Tag is reflected. 3473 * 3474 * Inputs 3475 * (endpoint, asoc, type, arg, commands) 3476 * 3477 * Outputs 3478 * (sctp_disposition_t) 3479 * 3480 * The return value is the disposition of the chunk. 3481 */ 3482 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3483 const struct sctp_endpoint *ep, 3484 const struct sctp_association *asoc, 3485 const sctp_subtype_t type, 3486 void *arg, 3487 sctp_cmd_seq_t *commands) 3488 { 3489 struct sctp_packet *packet = NULL; 3490 struct sctp_chunk *chunk = arg; 3491 struct sctp_chunk *shut; 3492 3493 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3494 3495 if (packet) { 3496 /* Make an SHUTDOWN_COMPLETE. 3497 * The T bit will be set if the asoc is NULL. 3498 */ 3499 shut = sctp_make_shutdown_complete(asoc, chunk); 3500 if (!shut) { 3501 sctp_ootb_pkt_free(packet); 3502 return SCTP_DISPOSITION_NOMEM; 3503 } 3504 3505 /* Reflect vtag if T-Bit is set */ 3506 if (sctp_test_T_bit(shut)) 3507 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3508 3509 /* Set the skb to the belonging sock for accounting. */ 3510 shut->skb->sk = ep->base.sk; 3511 3512 sctp_packet_append_chunk(packet, shut); 3513 3514 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3515 SCTP_PACKET(packet)); 3516 3517 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3518 3519 /* If the chunk length is invalid, we don't want to process 3520 * the reset of the packet. 3521 */ 3522 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3523 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3524 3525 /* We need to discard the rest of the packet to prevent 3526 * potential bomming attacks from additional bundled chunks. 3527 * This is documented in SCTP Threats ID. 3528 */ 3529 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3530 } 3531 3532 return SCTP_DISPOSITION_NOMEM; 3533 } 3534 3535 /* 3536 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3537 * 3538 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3539 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3540 * procedures in section 8.4 SHOULD be followed, in other words it 3541 * should be treated as an Out Of The Blue packet. 3542 * [This means that we do NOT check the Verification Tag on these 3543 * chunks. --piggy ] 3544 * 3545 */ 3546 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3547 const struct sctp_endpoint *ep, 3548 const struct sctp_association *asoc, 3549 const sctp_subtype_t type, 3550 void *arg, 3551 sctp_cmd_seq_t *commands) 3552 { 3553 struct sctp_chunk *chunk = arg; 3554 3555 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3556 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3557 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3558 commands); 3559 3560 /* Although we do have an association in this case, it corresponds 3561 * to a restarted association. So the packet is treated as an OOTB 3562 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3563 * called with a NULL association. 3564 */ 3565 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3566 3567 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3568 } 3569 3570 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3571 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3572 const struct sctp_endpoint *ep, 3573 const struct sctp_association *asoc, 3574 const sctp_subtype_t type, void *arg, 3575 sctp_cmd_seq_t *commands) 3576 { 3577 struct sctp_chunk *chunk = arg; 3578 struct sctp_chunk *asconf_ack = NULL; 3579 struct sctp_paramhdr *err_param = NULL; 3580 sctp_addiphdr_t *hdr; 3581 union sctp_addr_param *addr_param; 3582 __u32 serial; 3583 int length; 3584 3585 if (!sctp_vtag_verify(chunk, asoc)) { 3586 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3587 SCTP_NULL()); 3588 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3589 } 3590 3591 /* ADD-IP: Section 4.1.1 3592 * This chunk MUST be sent in an authenticated way by using 3593 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3594 * is received unauthenticated it MUST be silently discarded as 3595 * described in [I-D.ietf-tsvwg-sctp-auth]. 3596 */ 3597 if (!net->sctp.addip_noauth && !chunk->auth) 3598 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3599 3600 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3601 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3602 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3603 commands); 3604 3605 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3606 serial = ntohl(hdr->serial); 3607 3608 addr_param = (union sctp_addr_param *)hdr->params; 3609 length = ntohs(addr_param->p.length); 3610 if (length < sizeof(sctp_paramhdr_t)) 3611 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3612 (void *)addr_param, commands); 3613 3614 /* Verify the ASCONF chunk before processing it. */ 3615 if (!sctp_verify_asconf(asoc, 3616 (sctp_paramhdr_t *)((void *)addr_param + length), 3617 (void *)chunk->chunk_end, 3618 &err_param)) 3619 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3620 (void *)err_param, commands); 3621 3622 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3623 * the endpoint stored in a new association variable 3624 * 'Peer-Serial-Number'. 3625 */ 3626 if (serial == asoc->peer.addip_serial + 1) { 3627 /* If this is the first instance of ASCONF in the packet, 3628 * we can clean our old ASCONF-ACKs. 3629 */ 3630 if (!chunk->has_asconf) 3631 sctp_assoc_clean_asconf_ack_cache(asoc); 3632 3633 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3634 * expected, process the ASCONF as described below and after 3635 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3636 * the response packet and cache a copy of it (in the event it 3637 * later needs to be retransmitted). 3638 * 3639 * Essentially, do V1-V5. 3640 */ 3641 asconf_ack = sctp_process_asconf((struct sctp_association *) 3642 asoc, chunk); 3643 if (!asconf_ack) 3644 return SCTP_DISPOSITION_NOMEM; 3645 } else if (serial < asoc->peer.addip_serial + 1) { 3646 /* ADDIP 5.2 E2) 3647 * If the value found in the Sequence Number is less than the 3648 * ('Peer- Sequence-Number' + 1), simply skip to the next 3649 * ASCONF, and include in the outbound response packet 3650 * any previously cached ASCONF-ACK response that was 3651 * sent and saved that matches the Sequence Number of the 3652 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3653 * Chunk exists. This will occur when an older ASCONF 3654 * arrives out of order. In such a case, the receiver 3655 * should skip the ASCONF Chunk and not include ASCONF-ACK 3656 * Chunk for that chunk. 3657 */ 3658 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3659 if (!asconf_ack) 3660 return SCTP_DISPOSITION_DISCARD; 3661 3662 /* Reset the transport so that we select the correct one 3663 * this time around. This is to make sure that we don't 3664 * accidentally use a stale transport that's been removed. 3665 */ 3666 asconf_ack->transport = NULL; 3667 } else { 3668 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3669 * it must be either a stale packet or from an attacker. 3670 */ 3671 return SCTP_DISPOSITION_DISCARD; 3672 } 3673 3674 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3675 * containing the ASCONF-ACK Chunks MUST be the source address of 3676 * the SCTP packet that held the ASCONF Chunks. 3677 * 3678 * To do this properly, we'll set the destination address of the chunk 3679 * and at the transmit time, will try look up the transport to use. 3680 * Since ASCONFs may be bundled, the correct transport may not be 3681 * created until we process the entire packet, thus this workaround. 3682 */ 3683 asconf_ack->dest = chunk->source; 3684 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3685 if (asoc->new_transport) { 3686 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3687 ((struct sctp_association *)asoc)->new_transport = NULL; 3688 } 3689 3690 return SCTP_DISPOSITION_CONSUME; 3691 } 3692 3693 /* 3694 * ADDIP Section 4.3 General rules for address manipulation 3695 * When building TLV parameters for the ASCONF Chunk that will add or 3696 * delete IP addresses the D0 to D13 rules should be applied: 3697 */ 3698 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3699 const struct sctp_endpoint *ep, 3700 const struct sctp_association *asoc, 3701 const sctp_subtype_t type, void *arg, 3702 sctp_cmd_seq_t *commands) 3703 { 3704 struct sctp_chunk *asconf_ack = arg; 3705 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3706 struct sctp_chunk *abort; 3707 struct sctp_paramhdr *err_param = NULL; 3708 sctp_addiphdr_t *addip_hdr; 3709 __u32 sent_serial, rcvd_serial; 3710 3711 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3712 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3713 SCTP_NULL()); 3714 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3715 } 3716 3717 /* ADD-IP, Section 4.1.2: 3718 * This chunk MUST be sent in an authenticated way by using 3719 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3720 * is received unauthenticated it MUST be silently discarded as 3721 * described in [I-D.ietf-tsvwg-sctp-auth]. 3722 */ 3723 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3724 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3725 3726 /* Make sure that the ADDIP chunk has a valid length. */ 3727 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3728 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3729 commands); 3730 3731 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3732 rcvd_serial = ntohl(addip_hdr->serial); 3733 3734 /* Verify the ASCONF-ACK chunk before processing it. */ 3735 if (!sctp_verify_asconf(asoc, 3736 (sctp_paramhdr_t *)addip_hdr->params, 3737 (void *)asconf_ack->chunk_end, 3738 &err_param)) 3739 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3740 (void *)err_param, commands); 3741 3742 if (last_asconf) { 3743 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3744 sent_serial = ntohl(addip_hdr->serial); 3745 } else { 3746 sent_serial = asoc->addip_serial - 1; 3747 } 3748 3749 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3750 * equal to the next serial number to be used but no ASCONF chunk is 3751 * outstanding the endpoint MUST ABORT the association. Note that a 3752 * sequence number is greater than if it is no more than 2^^31-1 3753 * larger than the current sequence number (using serial arithmetic). 3754 */ 3755 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3756 !(asoc->addip_last_asconf)) { 3757 abort = sctp_make_abort(asoc, asconf_ack, 3758 sizeof(sctp_errhdr_t)); 3759 if (abort) { 3760 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3761 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3762 SCTP_CHUNK(abort)); 3763 } 3764 /* We are going to ABORT, so we might as well stop 3765 * processing the rest of the chunks in the packet. 3766 */ 3767 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3768 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3769 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3770 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3771 SCTP_ERROR(ECONNABORTED)); 3772 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3773 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3774 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3775 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3776 return SCTP_DISPOSITION_ABORT; 3777 } 3778 3779 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3780 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3781 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3782 3783 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3784 asconf_ack)) { 3785 /* Successfully processed ASCONF_ACK. We can 3786 * release the next asconf if we have one. 3787 */ 3788 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3789 SCTP_NULL()); 3790 return SCTP_DISPOSITION_CONSUME; 3791 } 3792 3793 abort = sctp_make_abort(asoc, asconf_ack, 3794 sizeof(sctp_errhdr_t)); 3795 if (abort) { 3796 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3797 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3798 SCTP_CHUNK(abort)); 3799 } 3800 /* We are going to ABORT, so we might as well stop 3801 * processing the rest of the chunks in the packet. 3802 */ 3803 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3804 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3805 SCTP_ERROR(ECONNABORTED)); 3806 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3807 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3808 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3809 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3810 return SCTP_DISPOSITION_ABORT; 3811 } 3812 3813 return SCTP_DISPOSITION_DISCARD; 3814 } 3815 3816 /* 3817 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3818 * 3819 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3820 * its cumulative TSN point to the value carried in the FORWARD TSN 3821 * chunk, and then MUST further advance its cumulative TSN point locally 3822 * if possible. 3823 * After the above processing, the data receiver MUST stop reporting any 3824 * missing TSNs earlier than or equal to the new cumulative TSN point. 3825 * 3826 * Verification Tag: 8.5 Verification Tag [Normal verification] 3827 * 3828 * The return value is the disposition of the chunk. 3829 */ 3830 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3831 const struct sctp_endpoint *ep, 3832 const struct sctp_association *asoc, 3833 const sctp_subtype_t type, 3834 void *arg, 3835 sctp_cmd_seq_t *commands) 3836 { 3837 struct sctp_chunk *chunk = arg; 3838 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3839 struct sctp_fwdtsn_skip *skip; 3840 __u16 len; 3841 __u32 tsn; 3842 3843 if (!sctp_vtag_verify(chunk, asoc)) { 3844 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3845 SCTP_NULL()); 3846 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3847 } 3848 3849 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3850 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3851 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3852 commands); 3853 3854 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3855 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3856 len = ntohs(chunk->chunk_hdr->length); 3857 len -= sizeof(struct sctp_chunkhdr); 3858 skb_pull(chunk->skb, len); 3859 3860 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3861 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3862 3863 /* The TSN is too high--silently discard the chunk and count on it 3864 * getting retransmitted later. 3865 */ 3866 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3867 goto discard_noforce; 3868 3869 /* Silently discard the chunk if stream-id is not valid */ 3870 sctp_walk_fwdtsn(skip, chunk) { 3871 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3872 goto discard_noforce; 3873 } 3874 3875 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3876 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3877 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3878 SCTP_CHUNK(chunk)); 3879 3880 /* Count this as receiving DATA. */ 3881 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3882 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3883 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3884 } 3885 3886 /* FIXME: For now send a SACK, but DATA processing may 3887 * send another. 3888 */ 3889 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3890 3891 return SCTP_DISPOSITION_CONSUME; 3892 3893 discard_noforce: 3894 return SCTP_DISPOSITION_DISCARD; 3895 } 3896 3897 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3898 struct net *net, 3899 const struct sctp_endpoint *ep, 3900 const struct sctp_association *asoc, 3901 const sctp_subtype_t type, 3902 void *arg, 3903 sctp_cmd_seq_t *commands) 3904 { 3905 struct sctp_chunk *chunk = arg; 3906 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3907 struct sctp_fwdtsn_skip *skip; 3908 __u16 len; 3909 __u32 tsn; 3910 3911 if (!sctp_vtag_verify(chunk, asoc)) { 3912 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3913 SCTP_NULL()); 3914 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3915 } 3916 3917 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3918 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3919 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3920 commands); 3921 3922 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3923 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3924 len = ntohs(chunk->chunk_hdr->length); 3925 len -= sizeof(struct sctp_chunkhdr); 3926 skb_pull(chunk->skb, len); 3927 3928 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3929 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3930 3931 /* The TSN is too high--silently discard the chunk and count on it 3932 * getting retransmitted later. 3933 */ 3934 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3935 goto gen_shutdown; 3936 3937 /* Silently discard the chunk if stream-id is not valid */ 3938 sctp_walk_fwdtsn(skip, chunk) { 3939 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3940 goto gen_shutdown; 3941 } 3942 3943 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3944 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3945 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3946 SCTP_CHUNK(chunk)); 3947 3948 /* Go a head and force a SACK, since we are shutting down. */ 3949 gen_shutdown: 3950 /* Implementor's Guide. 3951 * 3952 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3953 * respond to each received packet containing one or more DATA chunk(s) 3954 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3955 */ 3956 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3957 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3958 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3959 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3960 3961 return SCTP_DISPOSITION_CONSUME; 3962 } 3963 3964 /* 3965 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3966 * 3967 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3968 * Identifier field. If this algorithm was not specified by the 3969 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3970 * during association setup, the AUTH chunk and all chunks after it MUST 3971 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3972 * defined in Section 4.1. 3973 * 3974 * If an endpoint with no shared key receives a Shared Key Identifier 3975 * other than 0, it MUST silently discard all authenticated chunks. If 3976 * the endpoint has at least one endpoint pair shared key for the peer, 3977 * it MUST use the key specified by the Shared Key Identifier if a 3978 * key has been configured for that Shared Key Identifier. If no 3979 * endpoint pair shared key has been configured for that Shared Key 3980 * Identifier, all authenticated chunks MUST be silently discarded. 3981 * 3982 * Verification Tag: 8.5 Verification Tag [Normal verification] 3983 * 3984 * The return value is the disposition of the chunk. 3985 */ 3986 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 3987 const struct sctp_endpoint *ep, 3988 const struct sctp_association *asoc, 3989 const sctp_subtype_t type, 3990 struct sctp_chunk *chunk) 3991 { 3992 struct sctp_authhdr *auth_hdr; 3993 struct sctp_hmac *hmac; 3994 unsigned int sig_len; 3995 __u16 key_id; 3996 __u8 *save_digest; 3997 __u8 *digest; 3998 3999 /* Pull in the auth header, so we can do some more verification */ 4000 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4001 chunk->subh.auth_hdr = auth_hdr; 4002 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4003 4004 /* Make sure that we support the HMAC algorithm from the auth 4005 * chunk. 4006 */ 4007 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4008 return SCTP_IERROR_AUTH_BAD_HMAC; 4009 4010 /* Make sure that the provided shared key identifier has been 4011 * configured 4012 */ 4013 key_id = ntohs(auth_hdr->shkey_id); 4014 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4015 return SCTP_IERROR_AUTH_BAD_KEYID; 4016 4017 4018 /* Make sure that the length of the signature matches what 4019 * we expect. 4020 */ 4021 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4022 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4023 if (sig_len != hmac->hmac_len) 4024 return SCTP_IERROR_PROTO_VIOLATION; 4025 4026 /* Now that we've done validation checks, we can compute and 4027 * verify the hmac. The steps involved are: 4028 * 1. Save the digest from the chunk. 4029 * 2. Zero out the digest in the chunk. 4030 * 3. Compute the new digest 4031 * 4. Compare saved and new digests. 4032 */ 4033 digest = auth_hdr->hmac; 4034 skb_pull(chunk->skb, sig_len); 4035 4036 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4037 if (!save_digest) 4038 goto nomem; 4039 4040 memset(digest, 0, sig_len); 4041 4042 sctp_auth_calculate_hmac(asoc, chunk->skb, 4043 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4044 GFP_ATOMIC); 4045 4046 /* Discard the packet if the digests do not match */ 4047 if (memcmp(save_digest, digest, sig_len)) { 4048 kfree(save_digest); 4049 return SCTP_IERROR_BAD_SIG; 4050 } 4051 4052 kfree(save_digest); 4053 chunk->auth = 1; 4054 4055 return SCTP_IERROR_NO_ERROR; 4056 nomem: 4057 return SCTP_IERROR_NOMEM; 4058 } 4059 4060 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4061 const struct sctp_endpoint *ep, 4062 const struct sctp_association *asoc, 4063 const sctp_subtype_t type, 4064 void *arg, 4065 sctp_cmd_seq_t *commands) 4066 { 4067 struct sctp_authhdr *auth_hdr; 4068 struct sctp_chunk *chunk = arg; 4069 struct sctp_chunk *err_chunk; 4070 sctp_ierror_t error; 4071 4072 /* Make sure that the peer has AUTH capable */ 4073 if (!asoc->peer.auth_capable) 4074 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4075 4076 if (!sctp_vtag_verify(chunk, asoc)) { 4077 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4078 SCTP_NULL()); 4079 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4080 } 4081 4082 /* Make sure that the AUTH chunk has valid length. */ 4083 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4084 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4085 commands); 4086 4087 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4088 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4089 switch (error) { 4090 case SCTP_IERROR_AUTH_BAD_HMAC: 4091 /* Generate the ERROR chunk and discard the rest 4092 * of the packet 4093 */ 4094 err_chunk = sctp_make_op_error(asoc, chunk, 4095 SCTP_ERROR_UNSUP_HMAC, 4096 &auth_hdr->hmac_id, 4097 sizeof(__u16), 0); 4098 if (err_chunk) { 4099 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4100 SCTP_CHUNK(err_chunk)); 4101 } 4102 /* Fall Through */ 4103 case SCTP_IERROR_AUTH_BAD_KEYID: 4104 case SCTP_IERROR_BAD_SIG: 4105 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4106 4107 case SCTP_IERROR_PROTO_VIOLATION: 4108 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4109 commands); 4110 4111 case SCTP_IERROR_NOMEM: 4112 return SCTP_DISPOSITION_NOMEM; 4113 4114 default: /* Prevent gcc warnings */ 4115 break; 4116 } 4117 4118 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4119 struct sctp_ulpevent *ev; 4120 4121 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4122 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4123 4124 if (!ev) 4125 return -ENOMEM; 4126 4127 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4128 SCTP_ULPEVENT(ev)); 4129 } 4130 4131 return SCTP_DISPOSITION_CONSUME; 4132 } 4133 4134 /* 4135 * Process an unknown chunk. 4136 * 4137 * Section: 3.2. Also, 2.1 in the implementor's guide. 4138 * 4139 * Chunk Types are encoded such that the highest-order two bits specify 4140 * the action that must be taken if the processing endpoint does not 4141 * recognize the Chunk Type. 4142 * 4143 * 00 - Stop processing this SCTP packet and discard it, do not process 4144 * any further chunks within it. 4145 * 4146 * 01 - Stop processing this SCTP packet and discard it, do not process 4147 * any further chunks within it, and report the unrecognized 4148 * chunk in an 'Unrecognized Chunk Type'. 4149 * 4150 * 10 - Skip this chunk and continue processing. 4151 * 4152 * 11 - Skip this chunk and continue processing, but report in an ERROR 4153 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4154 * 4155 * The return value is the disposition of the chunk. 4156 */ 4157 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4158 const struct sctp_endpoint *ep, 4159 const struct sctp_association *asoc, 4160 const sctp_subtype_t type, 4161 void *arg, 4162 sctp_cmd_seq_t *commands) 4163 { 4164 struct sctp_chunk *unk_chunk = arg; 4165 struct sctp_chunk *err_chunk; 4166 sctp_chunkhdr_t *hdr; 4167 4168 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4169 4170 if (!sctp_vtag_verify(unk_chunk, asoc)) 4171 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4172 4173 /* Make sure that the chunk has a valid length. 4174 * Since we don't know the chunk type, we use a general 4175 * chunkhdr structure to make a comparison. 4176 */ 4177 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4178 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4179 commands); 4180 4181 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4182 case SCTP_CID_ACTION_DISCARD: 4183 /* Discard the packet. */ 4184 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4185 case SCTP_CID_ACTION_DISCARD_ERR: 4186 /* Generate an ERROR chunk as response. */ 4187 hdr = unk_chunk->chunk_hdr; 4188 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4189 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4190 WORD_ROUND(ntohs(hdr->length)), 4191 0); 4192 if (err_chunk) { 4193 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4194 SCTP_CHUNK(err_chunk)); 4195 } 4196 4197 /* Discard the packet. */ 4198 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4199 return SCTP_DISPOSITION_CONSUME; 4200 case SCTP_CID_ACTION_SKIP: 4201 /* Skip the chunk. */ 4202 return SCTP_DISPOSITION_DISCARD; 4203 case SCTP_CID_ACTION_SKIP_ERR: 4204 /* Generate an ERROR chunk as response. */ 4205 hdr = unk_chunk->chunk_hdr; 4206 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4207 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4208 WORD_ROUND(ntohs(hdr->length)), 4209 0); 4210 if (err_chunk) { 4211 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4212 SCTP_CHUNK(err_chunk)); 4213 } 4214 /* Skip the chunk. */ 4215 return SCTP_DISPOSITION_CONSUME; 4216 default: 4217 break; 4218 } 4219 4220 return SCTP_DISPOSITION_DISCARD; 4221 } 4222 4223 /* 4224 * Discard the chunk. 4225 * 4226 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4227 * [Too numerous to mention...] 4228 * Verification Tag: No verification needed. 4229 * Inputs 4230 * (endpoint, asoc, chunk) 4231 * 4232 * Outputs 4233 * (asoc, reply_msg, msg_up, timers, counters) 4234 * 4235 * The return value is the disposition of the chunk. 4236 */ 4237 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4238 const struct sctp_endpoint *ep, 4239 const struct sctp_association *asoc, 4240 const sctp_subtype_t type, 4241 void *arg, 4242 sctp_cmd_seq_t *commands) 4243 { 4244 struct sctp_chunk *chunk = arg; 4245 4246 /* Make sure that the chunk has a valid length. 4247 * Since we don't know the chunk type, we use a general 4248 * chunkhdr structure to make a comparison. 4249 */ 4250 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4251 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4252 commands); 4253 4254 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4255 4256 return SCTP_DISPOSITION_DISCARD; 4257 } 4258 4259 /* 4260 * Discard the whole packet. 4261 * 4262 * Section: 8.4 2) 4263 * 4264 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4265 * silently discard the OOTB packet and take no further action. 4266 * 4267 * Verification Tag: No verification necessary 4268 * 4269 * Inputs 4270 * (endpoint, asoc, chunk) 4271 * 4272 * Outputs 4273 * (asoc, reply_msg, msg_up, timers, counters) 4274 * 4275 * The return value is the disposition of the chunk. 4276 */ 4277 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4278 const struct sctp_endpoint *ep, 4279 const struct sctp_association *asoc, 4280 const sctp_subtype_t type, 4281 void *arg, 4282 sctp_cmd_seq_t *commands) 4283 { 4284 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4285 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4286 4287 return SCTP_DISPOSITION_CONSUME; 4288 } 4289 4290 4291 /* 4292 * The other end is violating protocol. 4293 * 4294 * Section: Not specified 4295 * Verification Tag: Not specified 4296 * Inputs 4297 * (endpoint, asoc, chunk) 4298 * 4299 * Outputs 4300 * (asoc, reply_msg, msg_up, timers, counters) 4301 * 4302 * We simply tag the chunk as a violation. The state machine will log 4303 * the violation and continue. 4304 */ 4305 sctp_disposition_t sctp_sf_violation(struct net *net, 4306 const struct sctp_endpoint *ep, 4307 const struct sctp_association *asoc, 4308 const sctp_subtype_t type, 4309 void *arg, 4310 sctp_cmd_seq_t *commands) 4311 { 4312 struct sctp_chunk *chunk = arg; 4313 4314 /* Make sure that the chunk has a valid length. */ 4315 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4316 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4317 commands); 4318 4319 return SCTP_DISPOSITION_VIOLATION; 4320 } 4321 4322 /* 4323 * Common function to handle a protocol violation. 4324 */ 4325 static sctp_disposition_t sctp_sf_abort_violation( 4326 struct net *net, 4327 const struct sctp_endpoint *ep, 4328 const struct sctp_association *asoc, 4329 void *arg, 4330 sctp_cmd_seq_t *commands, 4331 const __u8 *payload, 4332 const size_t paylen) 4333 { 4334 struct sctp_packet *packet = NULL; 4335 struct sctp_chunk *chunk = arg; 4336 struct sctp_chunk *abort = NULL; 4337 4338 /* SCTP-AUTH, Section 6.3: 4339 * It should be noted that if the receiver wants to tear 4340 * down an association in an authenticated way only, the 4341 * handling of malformed packets should not result in 4342 * tearing down the association. 4343 * 4344 * This means that if we only want to abort associations 4345 * in an authenticated way (i.e AUTH+ABORT), then we 4346 * can't destroy this association just because the packet 4347 * was malformed. 4348 */ 4349 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4350 goto discard; 4351 4352 /* Make the abort chunk. */ 4353 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4354 if (!abort) 4355 goto nomem; 4356 4357 if (asoc) { 4358 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4359 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4360 !asoc->peer.i.init_tag) { 4361 sctp_initack_chunk_t *initack; 4362 4363 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4364 if (!sctp_chunk_length_valid(chunk, 4365 sizeof(sctp_initack_chunk_t))) 4366 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4367 else { 4368 unsigned int inittag; 4369 4370 inittag = ntohl(initack->init_hdr.init_tag); 4371 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4372 SCTP_U32(inittag)); 4373 } 4374 } 4375 4376 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4377 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4378 4379 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4380 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4381 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4382 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4383 SCTP_ERROR(ECONNREFUSED)); 4384 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4385 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4386 } else { 4387 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4388 SCTP_ERROR(ECONNABORTED)); 4389 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4390 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4391 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4392 } 4393 } else { 4394 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4395 4396 if (!packet) 4397 goto nomem_pkt; 4398 4399 if (sctp_test_T_bit(abort)) 4400 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4401 4402 abort->skb->sk = ep->base.sk; 4403 4404 sctp_packet_append_chunk(packet, abort); 4405 4406 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4407 SCTP_PACKET(packet)); 4408 4409 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4410 } 4411 4412 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4413 4414 discard: 4415 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4416 return SCTP_DISPOSITION_ABORT; 4417 4418 nomem_pkt: 4419 sctp_chunk_free(abort); 4420 nomem: 4421 return SCTP_DISPOSITION_NOMEM; 4422 } 4423 4424 /* 4425 * Handle a protocol violation when the chunk length is invalid. 4426 * "Invalid" length is identified as smaller than the minimal length a 4427 * given chunk can be. For example, a SACK chunk has invalid length 4428 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4429 * 4430 * We inform the other end by sending an ABORT with a Protocol Violation 4431 * error code. 4432 * 4433 * Section: Not specified 4434 * Verification Tag: Nothing to do 4435 * Inputs 4436 * (endpoint, asoc, chunk) 4437 * 4438 * Outputs 4439 * (reply_msg, msg_up, counters) 4440 * 4441 * Generate an ABORT chunk and terminate the association. 4442 */ 4443 static sctp_disposition_t sctp_sf_violation_chunklen( 4444 struct net *net, 4445 const struct sctp_endpoint *ep, 4446 const struct sctp_association *asoc, 4447 const sctp_subtype_t type, 4448 void *arg, 4449 sctp_cmd_seq_t *commands) 4450 { 4451 static const char err_str[] = "The following chunk had invalid length:"; 4452 4453 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4454 sizeof(err_str)); 4455 } 4456 4457 /* 4458 * Handle a protocol violation when the parameter length is invalid. 4459 * If the length is smaller than the minimum length of a given parameter, 4460 * or accumulated length in multi parameters exceeds the end of the chunk, 4461 * the length is considered as invalid. 4462 */ 4463 static sctp_disposition_t sctp_sf_violation_paramlen( 4464 struct net *net, 4465 const struct sctp_endpoint *ep, 4466 const struct sctp_association *asoc, 4467 const sctp_subtype_t type, 4468 void *arg, void *ext, 4469 sctp_cmd_seq_t *commands) 4470 { 4471 struct sctp_chunk *chunk = arg; 4472 struct sctp_paramhdr *param = ext; 4473 struct sctp_chunk *abort = NULL; 4474 4475 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4476 goto discard; 4477 4478 /* Make the abort chunk. */ 4479 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4480 if (!abort) 4481 goto nomem; 4482 4483 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4484 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4485 4486 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4487 SCTP_ERROR(ECONNABORTED)); 4488 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4489 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4490 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4491 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4492 4493 discard: 4494 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4495 return SCTP_DISPOSITION_ABORT; 4496 nomem: 4497 return SCTP_DISPOSITION_NOMEM; 4498 } 4499 4500 /* Handle a protocol violation when the peer trying to advance the 4501 * cumulative tsn ack to a point beyond the max tsn currently sent. 4502 * 4503 * We inform the other end by sending an ABORT with a Protocol Violation 4504 * error code. 4505 */ 4506 static sctp_disposition_t sctp_sf_violation_ctsn( 4507 struct net *net, 4508 const struct sctp_endpoint *ep, 4509 const struct sctp_association *asoc, 4510 const sctp_subtype_t type, 4511 void *arg, 4512 sctp_cmd_seq_t *commands) 4513 { 4514 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4515 4516 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4517 sizeof(err_str)); 4518 } 4519 4520 /* Handle protocol violation of an invalid chunk bundling. For example, 4521 * when we have an association and we receive bundled INIT-ACK, or 4522 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4523 * statement from the specs. Additionally, there might be an attacker 4524 * on the path and we may not want to continue this communication. 4525 */ 4526 static sctp_disposition_t sctp_sf_violation_chunk( 4527 struct net *net, 4528 const struct sctp_endpoint *ep, 4529 const struct sctp_association *asoc, 4530 const sctp_subtype_t type, 4531 void *arg, 4532 sctp_cmd_seq_t *commands) 4533 { 4534 static const char err_str[] = "The following chunk violates protocol:"; 4535 4536 if (!asoc) 4537 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4538 4539 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4540 sizeof(err_str)); 4541 } 4542 /*************************************************************************** 4543 * These are the state functions for handling primitive (Section 10) events. 4544 ***************************************************************************/ 4545 /* 4546 * sctp_sf_do_prm_asoc 4547 * 4548 * Section: 10.1 ULP-to-SCTP 4549 * B) Associate 4550 * 4551 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4552 * outbound stream count) 4553 * -> association id [,destination transport addr list] [,outbound stream 4554 * count] 4555 * 4556 * This primitive allows the upper layer to initiate an association to a 4557 * specific peer endpoint. 4558 * 4559 * The peer endpoint shall be specified by one of the transport addresses 4560 * which defines the endpoint (see Section 1.4). If the local SCTP 4561 * instance has not been initialized, the ASSOCIATE is considered an 4562 * error. 4563 * [This is not relevant for the kernel implementation since we do all 4564 * initialization at boot time. It we hadn't initialized we wouldn't 4565 * get anywhere near this code.] 4566 * 4567 * An association id, which is a local handle to the SCTP association, 4568 * will be returned on successful establishment of the association. If 4569 * SCTP is not able to open an SCTP association with the peer endpoint, 4570 * an error is returned. 4571 * [In the kernel implementation, the struct sctp_association needs to 4572 * be created BEFORE causing this primitive to run.] 4573 * 4574 * Other association parameters may be returned, including the 4575 * complete destination transport addresses of the peer as well as the 4576 * outbound stream count of the local endpoint. One of the transport 4577 * address from the returned destination addresses will be selected by 4578 * the local endpoint as default primary path for sending SCTP packets 4579 * to this peer. The returned "destination transport addr list" can 4580 * be used by the ULP to change the default primary path or to force 4581 * sending a packet to a specific transport address. [All of this 4582 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4583 * function.] 4584 * 4585 * Mandatory attributes: 4586 * 4587 * o local SCTP instance name - obtained from the INITIALIZE operation. 4588 * [This is the argument asoc.] 4589 * o destination transport addr - specified as one of the transport 4590 * addresses of the peer endpoint with which the association is to be 4591 * established. 4592 * [This is asoc->peer.active_path.] 4593 * o outbound stream count - the number of outbound streams the ULP 4594 * would like to open towards this peer endpoint. 4595 * [BUG: This is not currently implemented.] 4596 * Optional attributes: 4597 * 4598 * None. 4599 * 4600 * The return value is a disposition. 4601 */ 4602 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4603 const struct sctp_endpoint *ep, 4604 const struct sctp_association *asoc, 4605 const sctp_subtype_t type, 4606 void *arg, 4607 sctp_cmd_seq_t *commands) 4608 { 4609 struct sctp_chunk *repl; 4610 struct sctp_association *my_asoc; 4611 4612 /* The comment below says that we enter COOKIE-WAIT AFTER 4613 * sending the INIT, but that doesn't actually work in our 4614 * implementation... 4615 */ 4616 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4617 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4618 4619 /* RFC 2960 5.1 Normal Establishment of an Association 4620 * 4621 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4622 * must provide its Verification Tag (Tag_A) in the Initiate 4623 * Tag field. Tag_A SHOULD be a random number in the range of 4624 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4625 */ 4626 4627 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4628 if (!repl) 4629 goto nomem; 4630 4631 /* Choose transport for INIT. */ 4632 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4633 SCTP_CHUNK(repl)); 4634 4635 /* Cast away the const modifier, as we want to just 4636 * rerun it through as a sideffect. 4637 */ 4638 my_asoc = (struct sctp_association *)asoc; 4639 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4640 4641 /* After sending the INIT, "A" starts the T1-init timer and 4642 * enters the COOKIE-WAIT state. 4643 */ 4644 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4645 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4646 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4647 return SCTP_DISPOSITION_CONSUME; 4648 4649 nomem: 4650 return SCTP_DISPOSITION_NOMEM; 4651 } 4652 4653 /* 4654 * Process the SEND primitive. 4655 * 4656 * Section: 10.1 ULP-to-SCTP 4657 * E) Send 4658 * 4659 * Format: SEND(association id, buffer address, byte count [,context] 4660 * [,stream id] [,life time] [,destination transport address] 4661 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4662 * -> result 4663 * 4664 * This is the main method to send user data via SCTP. 4665 * 4666 * Mandatory attributes: 4667 * 4668 * o association id - local handle to the SCTP association 4669 * 4670 * o buffer address - the location where the user message to be 4671 * transmitted is stored; 4672 * 4673 * o byte count - The size of the user data in number of bytes; 4674 * 4675 * Optional attributes: 4676 * 4677 * o context - an optional 32 bit integer that will be carried in the 4678 * sending failure notification to the ULP if the transportation of 4679 * this User Message fails. 4680 * 4681 * o stream id - to indicate which stream to send the data on. If not 4682 * specified, stream 0 will be used. 4683 * 4684 * o life time - specifies the life time of the user data. The user data 4685 * will not be sent by SCTP after the life time expires. This 4686 * parameter can be used to avoid efforts to transmit stale 4687 * user messages. SCTP notifies the ULP if the data cannot be 4688 * initiated to transport (i.e. sent to the destination via SCTP's 4689 * send primitive) within the life time variable. However, the 4690 * user data will be transmitted if SCTP has attempted to transmit a 4691 * chunk before the life time expired. 4692 * 4693 * o destination transport address - specified as one of the destination 4694 * transport addresses of the peer endpoint to which this packet 4695 * should be sent. Whenever possible, SCTP should use this destination 4696 * transport address for sending the packets, instead of the current 4697 * primary path. 4698 * 4699 * o unorder flag - this flag, if present, indicates that the user 4700 * would like the data delivered in an unordered fashion to the peer 4701 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4702 * message). 4703 * 4704 * o no-bundle flag - instructs SCTP not to bundle this user data with 4705 * other outbound DATA chunks. SCTP MAY still bundle even when 4706 * this flag is present, when faced with network congestion. 4707 * 4708 * o payload protocol-id - A 32 bit unsigned integer that is to be 4709 * passed to the peer indicating the type of payload protocol data 4710 * being transmitted. This value is passed as opaque data by SCTP. 4711 * 4712 * The return value is the disposition. 4713 */ 4714 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4715 const struct sctp_endpoint *ep, 4716 const struct sctp_association *asoc, 4717 const sctp_subtype_t type, 4718 void *arg, 4719 sctp_cmd_seq_t *commands) 4720 { 4721 struct sctp_datamsg *msg = arg; 4722 4723 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4724 return SCTP_DISPOSITION_CONSUME; 4725 } 4726 4727 /* 4728 * Process the SHUTDOWN primitive. 4729 * 4730 * Section: 10.1: 4731 * C) Shutdown 4732 * 4733 * Format: SHUTDOWN(association id) 4734 * -> result 4735 * 4736 * Gracefully closes an association. Any locally queued user data 4737 * will be delivered to the peer. The association will be terminated only 4738 * after the peer acknowledges all the SCTP packets sent. A success code 4739 * will be returned on successful termination of the association. If 4740 * attempting to terminate the association results in a failure, an error 4741 * code shall be returned. 4742 * 4743 * Mandatory attributes: 4744 * 4745 * o association id - local handle to the SCTP association 4746 * 4747 * Optional attributes: 4748 * 4749 * None. 4750 * 4751 * The return value is the disposition. 4752 */ 4753 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4754 struct net *net, 4755 const struct sctp_endpoint *ep, 4756 const struct sctp_association *asoc, 4757 const sctp_subtype_t type, 4758 void *arg, 4759 sctp_cmd_seq_t *commands) 4760 { 4761 int disposition; 4762 4763 /* From 9.2 Shutdown of an Association 4764 * Upon receipt of the SHUTDOWN primitive from its upper 4765 * layer, the endpoint enters SHUTDOWN-PENDING state and 4766 * remains there until all outstanding data has been 4767 * acknowledged by its peer. The endpoint accepts no new data 4768 * from its upper layer, but retransmits data to the far end 4769 * if necessary to fill gaps. 4770 */ 4771 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4772 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4773 4774 disposition = SCTP_DISPOSITION_CONSUME; 4775 if (sctp_outq_is_empty(&asoc->outqueue)) { 4776 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4777 arg, commands); 4778 } 4779 return disposition; 4780 } 4781 4782 /* 4783 * Process the ABORT primitive. 4784 * 4785 * Section: 10.1: 4786 * C) Abort 4787 * 4788 * Format: Abort(association id [, cause code]) 4789 * -> result 4790 * 4791 * Ungracefully closes an association. Any locally queued user data 4792 * will be discarded and an ABORT chunk is sent to the peer. A success code 4793 * will be returned on successful abortion of the association. If 4794 * attempting to abort the association results in a failure, an error 4795 * code shall be returned. 4796 * 4797 * Mandatory attributes: 4798 * 4799 * o association id - local handle to the SCTP association 4800 * 4801 * Optional attributes: 4802 * 4803 * o cause code - reason of the abort to be passed to the peer 4804 * 4805 * None. 4806 * 4807 * The return value is the disposition. 4808 */ 4809 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4810 struct net *net, 4811 const struct sctp_endpoint *ep, 4812 const struct sctp_association *asoc, 4813 const sctp_subtype_t type, 4814 void *arg, 4815 sctp_cmd_seq_t *commands) 4816 { 4817 /* From 9.1 Abort of an Association 4818 * Upon receipt of the ABORT primitive from its upper 4819 * layer, the endpoint enters CLOSED state and 4820 * discard all outstanding data has been 4821 * acknowledged by its peer. The endpoint accepts no new data 4822 * from its upper layer, but retransmits data to the far end 4823 * if necessary to fill gaps. 4824 */ 4825 struct sctp_chunk *abort = arg; 4826 sctp_disposition_t retval; 4827 4828 retval = SCTP_DISPOSITION_CONSUME; 4829 4830 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4831 4832 /* Even if we can't send the ABORT due to low memory delete the 4833 * TCB. This is a departure from our typical NOMEM handling. 4834 */ 4835 4836 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4837 SCTP_ERROR(ECONNABORTED)); 4838 /* Delete the established association. */ 4839 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4840 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4841 4842 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4843 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4844 4845 return retval; 4846 } 4847 4848 /* We tried an illegal operation on an association which is closed. */ 4849 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4850 const struct sctp_endpoint *ep, 4851 const struct sctp_association *asoc, 4852 const sctp_subtype_t type, 4853 void *arg, 4854 sctp_cmd_seq_t *commands) 4855 { 4856 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4857 return SCTP_DISPOSITION_CONSUME; 4858 } 4859 4860 /* We tried an illegal operation on an association which is shutting 4861 * down. 4862 */ 4863 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4864 const struct sctp_endpoint *ep, 4865 const struct sctp_association *asoc, 4866 const sctp_subtype_t type, 4867 void *arg, 4868 sctp_cmd_seq_t *commands) 4869 { 4870 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4871 SCTP_ERROR(-ESHUTDOWN)); 4872 return SCTP_DISPOSITION_CONSUME; 4873 } 4874 4875 /* 4876 * sctp_cookie_wait_prm_shutdown 4877 * 4878 * Section: 4 Note: 2 4879 * Verification Tag: 4880 * Inputs 4881 * (endpoint, asoc) 4882 * 4883 * The RFC does not explicitly address this issue, but is the route through the 4884 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4885 * 4886 * Outputs 4887 * (timers) 4888 */ 4889 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4890 struct net *net, 4891 const struct sctp_endpoint *ep, 4892 const struct sctp_association *asoc, 4893 const sctp_subtype_t type, 4894 void *arg, 4895 sctp_cmd_seq_t *commands) 4896 { 4897 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4898 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4899 4900 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4901 SCTP_STATE(SCTP_STATE_CLOSED)); 4902 4903 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4904 4905 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4906 4907 return SCTP_DISPOSITION_DELETE_TCB; 4908 } 4909 4910 /* 4911 * sctp_cookie_echoed_prm_shutdown 4912 * 4913 * Section: 4 Note: 2 4914 * Verification Tag: 4915 * Inputs 4916 * (endpoint, asoc) 4917 * 4918 * The RFC does not explcitly address this issue, but is the route through the 4919 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4920 * 4921 * Outputs 4922 * (timers) 4923 */ 4924 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4925 struct net *net, 4926 const struct sctp_endpoint *ep, 4927 const struct sctp_association *asoc, 4928 const sctp_subtype_t type, 4929 void *arg, sctp_cmd_seq_t *commands) 4930 { 4931 /* There is a single T1 timer, so we should be able to use 4932 * common function with the COOKIE-WAIT state. 4933 */ 4934 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 4935 } 4936 4937 /* 4938 * sctp_sf_cookie_wait_prm_abort 4939 * 4940 * Section: 4 Note: 2 4941 * Verification Tag: 4942 * Inputs 4943 * (endpoint, asoc) 4944 * 4945 * The RFC does not explicitly address this issue, but is the route through the 4946 * state table when someone issues an abort while in COOKIE_WAIT state. 4947 * 4948 * Outputs 4949 * (timers) 4950 */ 4951 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4952 struct net *net, 4953 const struct sctp_endpoint *ep, 4954 const struct sctp_association *asoc, 4955 const sctp_subtype_t type, 4956 void *arg, 4957 sctp_cmd_seq_t *commands) 4958 { 4959 struct sctp_chunk *abort = arg; 4960 sctp_disposition_t retval; 4961 4962 /* Stop T1-init timer */ 4963 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4964 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4965 retval = SCTP_DISPOSITION_CONSUME; 4966 4967 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4968 4969 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4970 SCTP_STATE(SCTP_STATE_CLOSED)); 4971 4972 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4973 4974 /* Even if we can't send the ABORT due to low memory delete the 4975 * TCB. This is a departure from our typical NOMEM handling. 4976 */ 4977 4978 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4979 SCTP_ERROR(ECONNREFUSED)); 4980 /* Delete the established association. */ 4981 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4982 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4983 4984 return retval; 4985 } 4986 4987 /* 4988 * sctp_sf_cookie_echoed_prm_abort 4989 * 4990 * Section: 4 Note: 3 4991 * Verification Tag: 4992 * Inputs 4993 * (endpoint, asoc) 4994 * 4995 * The RFC does not explcitly address this issue, but is the route through the 4996 * state table when someone issues an abort while in COOKIE_ECHOED state. 4997 * 4998 * Outputs 4999 * (timers) 5000 */ 5001 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 5002 struct net *net, 5003 const struct sctp_endpoint *ep, 5004 const struct sctp_association *asoc, 5005 const sctp_subtype_t type, 5006 void *arg, 5007 sctp_cmd_seq_t *commands) 5008 { 5009 /* There is a single T1 timer, so we should be able to use 5010 * common function with the COOKIE-WAIT state. 5011 */ 5012 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5013 } 5014 5015 /* 5016 * sctp_sf_shutdown_pending_prm_abort 5017 * 5018 * Inputs 5019 * (endpoint, asoc) 5020 * 5021 * The RFC does not explicitly address this issue, but is the route through the 5022 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5023 * 5024 * Outputs 5025 * (timers) 5026 */ 5027 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5028 struct net *net, 5029 const struct sctp_endpoint *ep, 5030 const struct sctp_association *asoc, 5031 const sctp_subtype_t type, 5032 void *arg, 5033 sctp_cmd_seq_t *commands) 5034 { 5035 /* Stop the T5-shutdown guard timer. */ 5036 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5037 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5038 5039 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5040 } 5041 5042 /* 5043 * sctp_sf_shutdown_sent_prm_abort 5044 * 5045 * Inputs 5046 * (endpoint, asoc) 5047 * 5048 * The RFC does not explicitly address this issue, but is the route through the 5049 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5050 * 5051 * Outputs 5052 * (timers) 5053 */ 5054 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5055 struct net *net, 5056 const struct sctp_endpoint *ep, 5057 const struct sctp_association *asoc, 5058 const sctp_subtype_t type, 5059 void *arg, 5060 sctp_cmd_seq_t *commands) 5061 { 5062 /* Stop the T2-shutdown timer. */ 5063 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5064 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5065 5066 /* Stop the T5-shutdown guard timer. */ 5067 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5068 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5069 5070 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5071 } 5072 5073 /* 5074 * sctp_sf_cookie_echoed_prm_abort 5075 * 5076 * Inputs 5077 * (endpoint, asoc) 5078 * 5079 * The RFC does not explcitly address this issue, but is the route through the 5080 * state table when someone issues an abort while in COOKIE_ECHOED state. 5081 * 5082 * Outputs 5083 * (timers) 5084 */ 5085 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5086 struct net *net, 5087 const struct sctp_endpoint *ep, 5088 const struct sctp_association *asoc, 5089 const sctp_subtype_t type, 5090 void *arg, 5091 sctp_cmd_seq_t *commands) 5092 { 5093 /* The same T2 timer, so we should be able to use 5094 * common function with the SHUTDOWN-SENT state. 5095 */ 5096 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5097 } 5098 5099 /* 5100 * Process the REQUESTHEARTBEAT primitive 5101 * 5102 * 10.1 ULP-to-SCTP 5103 * J) Request Heartbeat 5104 * 5105 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5106 * 5107 * -> result 5108 * 5109 * Instructs the local endpoint to perform a HeartBeat on the specified 5110 * destination transport address of the given association. The returned 5111 * result should indicate whether the transmission of the HEARTBEAT 5112 * chunk to the destination address is successful. 5113 * 5114 * Mandatory attributes: 5115 * 5116 * o association id - local handle to the SCTP association 5117 * 5118 * o destination transport address - the transport address of the 5119 * association on which a heartbeat should be issued. 5120 */ 5121 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5122 struct net *net, 5123 const struct sctp_endpoint *ep, 5124 const struct sctp_association *asoc, 5125 const sctp_subtype_t type, 5126 void *arg, 5127 sctp_cmd_seq_t *commands) 5128 { 5129 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5130 (struct sctp_transport *)arg, commands)) 5131 return SCTP_DISPOSITION_NOMEM; 5132 5133 /* 5134 * RFC 2960 (bis), section 8.3 5135 * 5136 * D) Request an on-demand HEARTBEAT on a specific destination 5137 * transport address of a given association. 5138 * 5139 * The endpoint should increment the respective error counter of 5140 * the destination transport address each time a HEARTBEAT is sent 5141 * to that address and not acknowledged within one RTO. 5142 * 5143 */ 5144 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5145 SCTP_TRANSPORT(arg)); 5146 return SCTP_DISPOSITION_CONSUME; 5147 } 5148 5149 /* 5150 * ADDIP Section 4.1 ASCONF Chunk Procedures 5151 * When an endpoint has an ASCONF signaled change to be sent to the 5152 * remote endpoint it should do A1 to A9 5153 */ 5154 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5155 const struct sctp_endpoint *ep, 5156 const struct sctp_association *asoc, 5157 const sctp_subtype_t type, 5158 void *arg, 5159 sctp_cmd_seq_t *commands) 5160 { 5161 struct sctp_chunk *chunk = arg; 5162 5163 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5164 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5165 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5166 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5167 return SCTP_DISPOSITION_CONSUME; 5168 } 5169 5170 /* 5171 * Ignore the primitive event 5172 * 5173 * The return value is the disposition of the primitive. 5174 */ 5175 sctp_disposition_t sctp_sf_ignore_primitive( 5176 struct net *net, 5177 const struct sctp_endpoint *ep, 5178 const struct sctp_association *asoc, 5179 const sctp_subtype_t type, 5180 void *arg, 5181 sctp_cmd_seq_t *commands) 5182 { 5183 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5184 type.primitive); 5185 5186 return SCTP_DISPOSITION_DISCARD; 5187 } 5188 5189 /*************************************************************************** 5190 * These are the state functions for the OTHER events. 5191 ***************************************************************************/ 5192 5193 /* 5194 * When the SCTP stack has no more user data to send or retransmit, this 5195 * notification is given to the user. Also, at the time when a user app 5196 * subscribes to this event, if there is no data to be sent or 5197 * retransmit, the stack will immediately send up this notification. 5198 */ 5199 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5200 struct net *net, 5201 const struct sctp_endpoint *ep, 5202 const struct sctp_association *asoc, 5203 const sctp_subtype_t type, 5204 void *arg, 5205 sctp_cmd_seq_t *commands) 5206 { 5207 struct sctp_ulpevent *event; 5208 5209 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5210 if (!event) 5211 return SCTP_DISPOSITION_NOMEM; 5212 5213 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5214 5215 return SCTP_DISPOSITION_CONSUME; 5216 } 5217 5218 /* 5219 * Start the shutdown negotiation. 5220 * 5221 * From Section 9.2: 5222 * Once all its outstanding data has been acknowledged, the endpoint 5223 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5224 * TSN Ack field the last sequential TSN it has received from the peer. 5225 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5226 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5227 * with the updated last sequential TSN received from its peer. 5228 * 5229 * The return value is the disposition. 5230 */ 5231 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5232 struct net *net, 5233 const struct sctp_endpoint *ep, 5234 const struct sctp_association *asoc, 5235 const sctp_subtype_t type, 5236 void *arg, 5237 sctp_cmd_seq_t *commands) 5238 { 5239 struct sctp_chunk *reply; 5240 5241 /* Once all its outstanding data has been acknowledged, the 5242 * endpoint shall send a SHUTDOWN chunk to its peer including 5243 * in the Cumulative TSN Ack field the last sequential TSN it 5244 * has received from the peer. 5245 */ 5246 reply = sctp_make_shutdown(asoc, NULL); 5247 if (!reply) 5248 goto nomem; 5249 5250 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5251 * T2-shutdown timer. 5252 */ 5253 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5254 5255 /* It shall then start the T2-shutdown timer */ 5256 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5257 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5258 5259 /* RFC 4960 Section 9.2 5260 * The sender of the SHUTDOWN MAY also start an overall guard timer 5261 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5262 */ 5263 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5264 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5265 5266 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5267 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5268 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5269 5270 /* and enter the SHUTDOWN-SENT state. */ 5271 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5272 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5273 5274 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5275 * 5276 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5277 * or SHUTDOWN-ACK. 5278 */ 5279 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5280 5281 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5282 5283 return SCTP_DISPOSITION_CONSUME; 5284 5285 nomem: 5286 return SCTP_DISPOSITION_NOMEM; 5287 } 5288 5289 /* 5290 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5291 * 5292 * From Section 9.2: 5293 * 5294 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5295 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5296 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5297 * endpoint must re-send the SHUTDOWN ACK. 5298 * 5299 * The return value is the disposition. 5300 */ 5301 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5302 struct net *net, 5303 const struct sctp_endpoint *ep, 5304 const struct sctp_association *asoc, 5305 const sctp_subtype_t type, 5306 void *arg, 5307 sctp_cmd_seq_t *commands) 5308 { 5309 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5310 struct sctp_chunk *reply; 5311 5312 /* There are 2 ways of getting here: 5313 * 1) called in response to a SHUTDOWN chunk 5314 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5315 * 5316 * For the case (2), the arg parameter is set to NULL. We need 5317 * to check that we have a chunk before accessing it's fields. 5318 */ 5319 if (chunk) { 5320 if (!sctp_vtag_verify(chunk, asoc)) 5321 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5322 5323 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5324 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5325 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5326 commands); 5327 } 5328 5329 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5330 * shall send a SHUTDOWN ACK ... 5331 */ 5332 reply = sctp_make_shutdown_ack(asoc, chunk); 5333 if (!reply) 5334 goto nomem; 5335 5336 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5337 * the T2-shutdown timer. 5338 */ 5339 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5340 5341 /* and start/restart a T2-shutdown timer of its own, */ 5342 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5343 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5344 5345 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5346 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5347 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5348 5349 /* Enter the SHUTDOWN-ACK-SENT state. */ 5350 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5351 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5352 5353 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5354 * 5355 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5356 * or SHUTDOWN-ACK. 5357 */ 5358 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5359 5360 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5361 5362 return SCTP_DISPOSITION_CONSUME; 5363 5364 nomem: 5365 return SCTP_DISPOSITION_NOMEM; 5366 } 5367 5368 /* 5369 * Ignore the event defined as other 5370 * 5371 * The return value is the disposition of the event. 5372 */ 5373 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5374 const struct sctp_endpoint *ep, 5375 const struct sctp_association *asoc, 5376 const sctp_subtype_t type, 5377 void *arg, 5378 sctp_cmd_seq_t *commands) 5379 { 5380 pr_debug("%s: the event other type:%d is ignored\n", 5381 __func__, type.other); 5382 5383 return SCTP_DISPOSITION_DISCARD; 5384 } 5385 5386 /************************************************************ 5387 * These are the state functions for handling timeout events. 5388 ************************************************************/ 5389 5390 /* 5391 * RTX Timeout 5392 * 5393 * Section: 6.3.3 Handle T3-rtx Expiration 5394 * 5395 * Whenever the retransmission timer T3-rtx expires for a destination 5396 * address, do the following: 5397 * [See below] 5398 * 5399 * The return value is the disposition of the chunk. 5400 */ 5401 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5402 const struct sctp_endpoint *ep, 5403 const struct sctp_association *asoc, 5404 const sctp_subtype_t type, 5405 void *arg, 5406 sctp_cmd_seq_t *commands) 5407 { 5408 struct sctp_transport *transport = arg; 5409 5410 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5411 5412 if (asoc->overall_error_count >= asoc->max_retrans) { 5413 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5414 /* 5415 * We are here likely because the receiver had its rwnd 5416 * closed for a while and we have not been able to 5417 * transmit the locally queued data within the maximum 5418 * retransmission attempts limit. Start the T5 5419 * shutdown guard timer to give the receiver one last 5420 * chance and some additional time to recover before 5421 * aborting. 5422 */ 5423 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5424 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5425 } else { 5426 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5427 SCTP_ERROR(ETIMEDOUT)); 5428 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5429 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5430 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5431 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5432 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5433 return SCTP_DISPOSITION_DELETE_TCB; 5434 } 5435 } 5436 5437 /* E1) For the destination address for which the timer 5438 * expires, adjust its ssthresh with rules defined in Section 5439 * 7.2.3 and set the cwnd <- MTU. 5440 */ 5441 5442 /* E2) For the destination address for which the timer 5443 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5444 * maximum value discussed in rule C7 above (RTO.max) may be 5445 * used to provide an upper bound to this doubling operation. 5446 */ 5447 5448 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5449 * outstanding DATA chunks for the address for which the 5450 * T3-rtx has expired will fit into a single packet, subject 5451 * to the MTU constraint for the path corresponding to the 5452 * destination transport address to which the retransmission 5453 * is being sent (this may be different from the address for 5454 * which the timer expires [see Section 6.4]). Call this 5455 * value K. Bundle and retransmit those K DATA chunks in a 5456 * single packet to the destination endpoint. 5457 * 5458 * Note: Any DATA chunks that were sent to the address for 5459 * which the T3-rtx timer expired but did not fit in one MTU 5460 * (rule E3 above), should be marked for retransmission and 5461 * sent as soon as cwnd allows (normally when a SACK arrives). 5462 */ 5463 5464 /* Do some failure management (Section 8.2). */ 5465 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5466 5467 /* NB: Rules E4 and F1 are implicit in R1. */ 5468 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5469 5470 return SCTP_DISPOSITION_CONSUME; 5471 } 5472 5473 /* 5474 * Generate delayed SACK on timeout 5475 * 5476 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5477 * 5478 * The guidelines on delayed acknowledgement algorithm specified in 5479 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5480 * acknowledgement SHOULD be generated for at least every second packet 5481 * (not every second DATA chunk) received, and SHOULD be generated 5482 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5483 * some situations it may be beneficial for an SCTP transmitter to be 5484 * more conservative than the algorithms detailed in this document 5485 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5486 * the following algorithms allow. 5487 */ 5488 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5489 const struct sctp_endpoint *ep, 5490 const struct sctp_association *asoc, 5491 const sctp_subtype_t type, 5492 void *arg, 5493 sctp_cmd_seq_t *commands) 5494 { 5495 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5496 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5497 return SCTP_DISPOSITION_CONSUME; 5498 } 5499 5500 /* 5501 * sctp_sf_t1_init_timer_expire 5502 * 5503 * Section: 4 Note: 2 5504 * Verification Tag: 5505 * Inputs 5506 * (endpoint, asoc) 5507 * 5508 * RFC 2960 Section 4 Notes 5509 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5510 * and re-start the T1-init timer without changing state. This MUST 5511 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5512 * endpoint MUST abort the initialization process and report the 5513 * error to SCTP user. 5514 * 5515 * Outputs 5516 * (timers, events) 5517 * 5518 */ 5519 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5520 const struct sctp_endpoint *ep, 5521 const struct sctp_association *asoc, 5522 const sctp_subtype_t type, 5523 void *arg, 5524 sctp_cmd_seq_t *commands) 5525 { 5526 struct sctp_chunk *repl = NULL; 5527 struct sctp_bind_addr *bp; 5528 int attempts = asoc->init_err_counter + 1; 5529 5530 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5531 5532 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5533 5534 if (attempts <= asoc->max_init_attempts) { 5535 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5536 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5537 if (!repl) 5538 return SCTP_DISPOSITION_NOMEM; 5539 5540 /* Choose transport for INIT. */ 5541 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5542 SCTP_CHUNK(repl)); 5543 5544 /* Issue a sideeffect to do the needed accounting. */ 5545 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5546 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5547 5548 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5549 } else { 5550 pr_debug("%s: giving up on INIT, attempts:%d " 5551 "max_init_attempts:%d\n", __func__, attempts, 5552 asoc->max_init_attempts); 5553 5554 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5555 SCTP_ERROR(ETIMEDOUT)); 5556 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5557 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5558 return SCTP_DISPOSITION_DELETE_TCB; 5559 } 5560 5561 return SCTP_DISPOSITION_CONSUME; 5562 } 5563 5564 /* 5565 * sctp_sf_t1_cookie_timer_expire 5566 * 5567 * Section: 4 Note: 2 5568 * Verification Tag: 5569 * Inputs 5570 * (endpoint, asoc) 5571 * 5572 * RFC 2960 Section 4 Notes 5573 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5574 * COOKIE ECHO and re-start the T1-cookie timer without changing 5575 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5576 * After that, the endpoint MUST abort the initialization process and 5577 * report the error to SCTP user. 5578 * 5579 * Outputs 5580 * (timers, events) 5581 * 5582 */ 5583 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5584 const struct sctp_endpoint *ep, 5585 const struct sctp_association *asoc, 5586 const sctp_subtype_t type, 5587 void *arg, 5588 sctp_cmd_seq_t *commands) 5589 { 5590 struct sctp_chunk *repl = NULL; 5591 int attempts = asoc->init_err_counter + 1; 5592 5593 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5594 5595 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5596 5597 if (attempts <= asoc->max_init_attempts) { 5598 repl = sctp_make_cookie_echo(asoc, NULL); 5599 if (!repl) 5600 return SCTP_DISPOSITION_NOMEM; 5601 5602 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5603 SCTP_CHUNK(repl)); 5604 /* Issue a sideeffect to do the needed accounting. */ 5605 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5606 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5607 5608 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5609 } else { 5610 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5611 SCTP_ERROR(ETIMEDOUT)); 5612 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5613 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5614 return SCTP_DISPOSITION_DELETE_TCB; 5615 } 5616 5617 return SCTP_DISPOSITION_CONSUME; 5618 } 5619 5620 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5621 * with the updated last sequential TSN received from its peer. 5622 * 5623 * An endpoint should limit the number of retransmissions of the 5624 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5625 * If this threshold is exceeded the endpoint should destroy the TCB and 5626 * MUST report the peer endpoint unreachable to the upper layer (and 5627 * thus the association enters the CLOSED state). The reception of any 5628 * packet from its peer (i.e. as the peer sends all of its queued DATA 5629 * chunks) should clear the endpoint's retransmission count and restart 5630 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5631 * all of its queued DATA chunks that have not yet been sent. 5632 */ 5633 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5634 const struct sctp_endpoint *ep, 5635 const struct sctp_association *asoc, 5636 const sctp_subtype_t type, 5637 void *arg, 5638 sctp_cmd_seq_t *commands) 5639 { 5640 struct sctp_chunk *reply = NULL; 5641 5642 pr_debug("%s: timer T2 expired\n", __func__); 5643 5644 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5645 5646 ((struct sctp_association *)asoc)->shutdown_retries++; 5647 5648 if (asoc->overall_error_count >= asoc->max_retrans) { 5649 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5650 SCTP_ERROR(ETIMEDOUT)); 5651 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5652 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5653 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5654 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5655 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5656 return SCTP_DISPOSITION_DELETE_TCB; 5657 } 5658 5659 switch (asoc->state) { 5660 case SCTP_STATE_SHUTDOWN_SENT: 5661 reply = sctp_make_shutdown(asoc, NULL); 5662 break; 5663 5664 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5665 reply = sctp_make_shutdown_ack(asoc, NULL); 5666 break; 5667 5668 default: 5669 BUG(); 5670 break; 5671 } 5672 5673 if (!reply) 5674 goto nomem; 5675 5676 /* Do some failure management (Section 8.2). 5677 * If we remove the transport an SHUTDOWN was last sent to, don't 5678 * do failure management. 5679 */ 5680 if (asoc->shutdown_last_sent_to) 5681 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5682 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5683 5684 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5685 * the T2-shutdown timer. 5686 */ 5687 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5688 5689 /* Restart the T2-shutdown timer. */ 5690 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5691 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5692 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5693 return SCTP_DISPOSITION_CONSUME; 5694 5695 nomem: 5696 return SCTP_DISPOSITION_NOMEM; 5697 } 5698 5699 /* 5700 * ADDIP Section 4.1 ASCONF CHunk Procedures 5701 * If the T4 RTO timer expires the endpoint should do B1 to B5 5702 */ 5703 sctp_disposition_t sctp_sf_t4_timer_expire( 5704 struct net *net, 5705 const struct sctp_endpoint *ep, 5706 const struct sctp_association *asoc, 5707 const sctp_subtype_t type, 5708 void *arg, 5709 sctp_cmd_seq_t *commands) 5710 { 5711 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5712 struct sctp_transport *transport = chunk->transport; 5713 5714 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5715 5716 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5717 * detection on the appropriate destination address as defined in 5718 * RFC2960 [5] section 8.1 and 8.2. 5719 */ 5720 if (transport) 5721 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5722 SCTP_TRANSPORT(transport)); 5723 5724 /* Reconfig T4 timer and transport. */ 5725 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5726 5727 /* ADDIP 4.1 B2) Increment the association error counters and perform 5728 * endpoint failure detection on the association as defined in 5729 * RFC2960 [5] section 8.1 and 8.2. 5730 * association error counter is incremented in SCTP_CMD_STRIKE. 5731 */ 5732 if (asoc->overall_error_count >= asoc->max_retrans) { 5733 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5734 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5735 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5736 SCTP_ERROR(ETIMEDOUT)); 5737 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5738 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5739 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5740 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5741 return SCTP_DISPOSITION_ABORT; 5742 } 5743 5744 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5745 * the ASCONF chunk was sent by doubling the RTO timer value. 5746 * This is done in SCTP_CMD_STRIKE. 5747 */ 5748 5749 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5750 * choose an alternate destination address (please refer to RFC2960 5751 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5752 * chunk, it MUST be the same (including its serial number) as the last 5753 * ASCONF sent. 5754 */ 5755 sctp_chunk_hold(asoc->addip_last_asconf); 5756 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5757 SCTP_CHUNK(asoc->addip_last_asconf)); 5758 5759 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5760 * destination is selected, then the RTO used will be that of the new 5761 * destination address. 5762 */ 5763 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5764 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5765 5766 return SCTP_DISPOSITION_CONSUME; 5767 } 5768 5769 /* sctpimpguide-05 Section 2.12.2 5770 * The sender of the SHUTDOWN MAY also start an overall guard timer 5771 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5772 * At the expiration of this timer the sender SHOULD abort the association 5773 * by sending an ABORT chunk. 5774 */ 5775 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5776 const struct sctp_endpoint *ep, 5777 const struct sctp_association *asoc, 5778 const sctp_subtype_t type, 5779 void *arg, 5780 sctp_cmd_seq_t *commands) 5781 { 5782 struct sctp_chunk *reply = NULL; 5783 5784 pr_debug("%s: timer T5 expired\n", __func__); 5785 5786 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5787 5788 reply = sctp_make_abort(asoc, NULL, 0); 5789 if (!reply) 5790 goto nomem; 5791 5792 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5793 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5794 SCTP_ERROR(ETIMEDOUT)); 5795 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5796 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5797 5798 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5799 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5800 5801 return SCTP_DISPOSITION_DELETE_TCB; 5802 nomem: 5803 return SCTP_DISPOSITION_NOMEM; 5804 } 5805 5806 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5807 * the association is automatically closed by starting the shutdown process. 5808 * The work that needs to be done is same as when SHUTDOWN is initiated by 5809 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5810 */ 5811 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5812 struct net *net, 5813 const struct sctp_endpoint *ep, 5814 const struct sctp_association *asoc, 5815 const sctp_subtype_t type, 5816 void *arg, 5817 sctp_cmd_seq_t *commands) 5818 { 5819 int disposition; 5820 5821 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5822 5823 /* From 9.2 Shutdown of an Association 5824 * Upon receipt of the SHUTDOWN primitive from its upper 5825 * layer, the endpoint enters SHUTDOWN-PENDING state and 5826 * remains there until all outstanding data has been 5827 * acknowledged by its peer. The endpoint accepts no new data 5828 * from its upper layer, but retransmits data to the far end 5829 * if necessary to fill gaps. 5830 */ 5831 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5832 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5833 5834 disposition = SCTP_DISPOSITION_CONSUME; 5835 if (sctp_outq_is_empty(&asoc->outqueue)) { 5836 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5837 arg, commands); 5838 } 5839 return disposition; 5840 } 5841 5842 /***************************************************************************** 5843 * These are sa state functions which could apply to all types of events. 5844 ****************************************************************************/ 5845 5846 /* 5847 * This table entry is not implemented. 5848 * 5849 * Inputs 5850 * (endpoint, asoc, chunk) 5851 * 5852 * The return value is the disposition of the chunk. 5853 */ 5854 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5855 const struct sctp_endpoint *ep, 5856 const struct sctp_association *asoc, 5857 const sctp_subtype_t type, 5858 void *arg, 5859 sctp_cmd_seq_t *commands) 5860 { 5861 return SCTP_DISPOSITION_NOT_IMPL; 5862 } 5863 5864 /* 5865 * This table entry represents a bug. 5866 * 5867 * Inputs 5868 * (endpoint, asoc, chunk) 5869 * 5870 * The return value is the disposition of the chunk. 5871 */ 5872 sctp_disposition_t sctp_sf_bug(struct net *net, 5873 const struct sctp_endpoint *ep, 5874 const struct sctp_association *asoc, 5875 const sctp_subtype_t type, 5876 void *arg, 5877 sctp_cmd_seq_t *commands) 5878 { 5879 return SCTP_DISPOSITION_BUG; 5880 } 5881 5882 /* 5883 * This table entry represents the firing of a timer in the wrong state. 5884 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5885 * when the association is in the wrong state. This event should 5886 * be ignored, so as to prevent any rearming of the timer. 5887 * 5888 * Inputs 5889 * (endpoint, asoc, chunk) 5890 * 5891 * The return value is the disposition of the chunk. 5892 */ 5893 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5894 const struct sctp_endpoint *ep, 5895 const struct sctp_association *asoc, 5896 const sctp_subtype_t type, 5897 void *arg, 5898 sctp_cmd_seq_t *commands) 5899 { 5900 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 5901 5902 return SCTP_DISPOSITION_CONSUME; 5903 } 5904 5905 /******************************************************************** 5906 * 2nd Level Abstractions 5907 ********************************************************************/ 5908 5909 /* Pull the SACK chunk based on the SACK header. */ 5910 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5911 { 5912 struct sctp_sackhdr *sack; 5913 unsigned int len; 5914 __u16 num_blocks; 5915 __u16 num_dup_tsns; 5916 5917 /* Protect ourselves from reading too far into 5918 * the skb from a bogus sender. 5919 */ 5920 sack = (struct sctp_sackhdr *) chunk->skb->data; 5921 5922 num_blocks = ntohs(sack->num_gap_ack_blocks); 5923 num_dup_tsns = ntohs(sack->num_dup_tsns); 5924 len = sizeof(struct sctp_sackhdr); 5925 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5926 if (len > chunk->skb->len) 5927 return NULL; 5928 5929 skb_pull(chunk->skb, len); 5930 5931 return sack; 5932 } 5933 5934 /* Create an ABORT packet to be sent as a response, with the specified 5935 * error causes. 5936 */ 5937 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 5938 const struct sctp_endpoint *ep, 5939 const struct sctp_association *asoc, 5940 struct sctp_chunk *chunk, 5941 const void *payload, 5942 size_t paylen) 5943 { 5944 struct sctp_packet *packet; 5945 struct sctp_chunk *abort; 5946 5947 packet = sctp_ootb_pkt_new(net, asoc, chunk); 5948 5949 if (packet) { 5950 /* Make an ABORT. 5951 * The T bit will be set if the asoc is NULL. 5952 */ 5953 abort = sctp_make_abort(asoc, chunk, paylen); 5954 if (!abort) { 5955 sctp_ootb_pkt_free(packet); 5956 return NULL; 5957 } 5958 5959 /* Reflect vtag if T-Bit is set */ 5960 if (sctp_test_T_bit(abort)) 5961 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5962 5963 /* Add specified error causes, i.e., payload, to the 5964 * end of the chunk. 5965 */ 5966 sctp_addto_chunk(abort, paylen, payload); 5967 5968 /* Set the skb to the belonging sock for accounting. */ 5969 abort->skb->sk = ep->base.sk; 5970 5971 sctp_packet_append_chunk(packet, abort); 5972 5973 } 5974 5975 return packet; 5976 } 5977 5978 /* Allocate a packet for responding in the OOTB conditions. */ 5979 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 5980 const struct sctp_association *asoc, 5981 const struct sctp_chunk *chunk) 5982 { 5983 struct sctp_packet *packet; 5984 struct sctp_transport *transport; 5985 __u16 sport; 5986 __u16 dport; 5987 __u32 vtag; 5988 5989 /* Get the source and destination port from the inbound packet. */ 5990 sport = ntohs(chunk->sctp_hdr->dest); 5991 dport = ntohs(chunk->sctp_hdr->source); 5992 5993 /* The V-tag is going to be the same as the inbound packet if no 5994 * association exists, otherwise, use the peer's vtag. 5995 */ 5996 if (asoc) { 5997 /* Special case the INIT-ACK as there is no peer's vtag 5998 * yet. 5999 */ 6000 switch (chunk->chunk_hdr->type) { 6001 case SCTP_CID_INIT_ACK: 6002 { 6003 sctp_initack_chunk_t *initack; 6004 6005 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6006 vtag = ntohl(initack->init_hdr.init_tag); 6007 break; 6008 } 6009 default: 6010 vtag = asoc->peer.i.init_tag; 6011 break; 6012 } 6013 } else { 6014 /* Special case the INIT and stale COOKIE_ECHO as there is no 6015 * vtag yet. 6016 */ 6017 switch (chunk->chunk_hdr->type) { 6018 case SCTP_CID_INIT: 6019 { 6020 sctp_init_chunk_t *init; 6021 6022 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6023 vtag = ntohl(init->init_hdr.init_tag); 6024 break; 6025 } 6026 default: 6027 vtag = ntohl(chunk->sctp_hdr->vtag); 6028 break; 6029 } 6030 } 6031 6032 /* Make a transport for the bucket, Eliza... */ 6033 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6034 if (!transport) 6035 goto nomem; 6036 6037 /* Cache a route for the transport with the chunk's destination as 6038 * the source address. 6039 */ 6040 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6041 sctp_sk(net->sctp.ctl_sock)); 6042 6043 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 6044 packet = sctp_packet_config(packet, vtag, 0); 6045 6046 return packet; 6047 6048 nomem: 6049 return NULL; 6050 } 6051 6052 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6053 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6054 { 6055 sctp_transport_free(packet->transport); 6056 } 6057 6058 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6059 static void sctp_send_stale_cookie_err(struct net *net, 6060 const struct sctp_endpoint *ep, 6061 const struct sctp_association *asoc, 6062 const struct sctp_chunk *chunk, 6063 sctp_cmd_seq_t *commands, 6064 struct sctp_chunk *err_chunk) 6065 { 6066 struct sctp_packet *packet; 6067 6068 if (err_chunk) { 6069 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6070 if (packet) { 6071 struct sctp_signed_cookie *cookie; 6072 6073 /* Override the OOTB vtag from the cookie. */ 6074 cookie = chunk->subh.cookie_hdr; 6075 packet->vtag = cookie->c.peer_vtag; 6076 6077 /* Set the skb to the belonging sock for accounting. */ 6078 err_chunk->skb->sk = ep->base.sk; 6079 sctp_packet_append_chunk(packet, err_chunk); 6080 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6081 SCTP_PACKET(packet)); 6082 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6083 } else 6084 sctp_chunk_free (err_chunk); 6085 } 6086 } 6087 6088 6089 /* Process a data chunk */ 6090 static int sctp_eat_data(const struct sctp_association *asoc, 6091 struct sctp_chunk *chunk, 6092 sctp_cmd_seq_t *commands) 6093 { 6094 sctp_datahdr_t *data_hdr; 6095 struct sctp_chunk *err; 6096 size_t datalen; 6097 sctp_verb_t deliver; 6098 int tmp; 6099 __u32 tsn; 6100 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6101 struct sock *sk = asoc->base.sk; 6102 struct net *net = sock_net(sk); 6103 u16 ssn; 6104 u16 sid; 6105 u8 ordered = 0; 6106 6107 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6108 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6109 6110 tsn = ntohl(data_hdr->tsn); 6111 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6112 6113 /* ASSERT: Now skb->data is really the user data. */ 6114 6115 /* Process ECN based congestion. 6116 * 6117 * Since the chunk structure is reused for all chunks within 6118 * a packet, we use ecn_ce_done to track if we've already 6119 * done CE processing for this packet. 6120 * 6121 * We need to do ECN processing even if we plan to discard the 6122 * chunk later. 6123 */ 6124 6125 if (!chunk->ecn_ce_done) { 6126 struct sctp_af *af; 6127 chunk->ecn_ce_done = 1; 6128 6129 af = sctp_get_af_specific( 6130 ipver2af(ip_hdr(chunk->skb)->version)); 6131 6132 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 6133 /* Do real work as sideffect. */ 6134 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6135 SCTP_U32(tsn)); 6136 } 6137 } 6138 6139 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6140 if (tmp < 0) { 6141 /* The TSN is too high--silently discard the chunk and 6142 * count on it getting retransmitted later. 6143 */ 6144 if (chunk->asoc) 6145 chunk->asoc->stats.outofseqtsns++; 6146 return SCTP_IERROR_HIGH_TSN; 6147 } else if (tmp > 0) { 6148 /* This is a duplicate. Record it. */ 6149 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6150 return SCTP_IERROR_DUP_TSN; 6151 } 6152 6153 /* This is a new TSN. */ 6154 6155 /* Discard if there is no room in the receive window. 6156 * Actually, allow a little bit of overflow (up to a MTU). 6157 */ 6158 datalen = ntohs(chunk->chunk_hdr->length); 6159 datalen -= sizeof(sctp_data_chunk_t); 6160 6161 deliver = SCTP_CMD_CHUNK_ULP; 6162 6163 /* Think about partial delivery. */ 6164 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6165 6166 /* Even if we don't accept this chunk there is 6167 * memory pressure. 6168 */ 6169 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6170 } 6171 6172 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6173 * seems a bit troublesome in that frag_point varies based on 6174 * PMTU. In cases, such as loopback, this might be a rather 6175 * large spill over. 6176 */ 6177 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6178 (datalen > asoc->rwnd + asoc->frag_point))) { 6179 6180 /* If this is the next TSN, consider reneging to make 6181 * room. Note: Playing nice with a confused sender. A 6182 * malicious sender can still eat up all our buffer 6183 * space and in the future we may want to detect and 6184 * do more drastic reneging. 6185 */ 6186 if (sctp_tsnmap_has_gap(map) && 6187 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6188 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6189 deliver = SCTP_CMD_RENEGE; 6190 } else { 6191 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6192 __func__, tsn, datalen, asoc->rwnd); 6193 6194 return SCTP_IERROR_IGNORE_TSN; 6195 } 6196 } 6197 6198 /* 6199 * Also try to renege to limit our memory usage in the event that 6200 * we are under memory pressure 6201 * If we can't renege, don't worry about it, the sk_rmem_schedule 6202 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6203 * memory usage too much 6204 */ 6205 if (*sk->sk_prot_creator->memory_pressure) { 6206 if (sctp_tsnmap_has_gap(map) && 6207 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6208 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6209 __func__, tsn); 6210 deliver = SCTP_CMD_RENEGE; 6211 } 6212 } 6213 6214 /* 6215 * Section 3.3.10.9 No User Data (9) 6216 * 6217 * Cause of error 6218 * --------------- 6219 * No User Data: This error cause is returned to the originator of a 6220 * DATA chunk if a received DATA chunk has no user data. 6221 */ 6222 if (unlikely(0 == datalen)) { 6223 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6224 if (err) { 6225 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6226 SCTP_CHUNK(err)); 6227 } 6228 /* We are going to ABORT, so we might as well stop 6229 * processing the rest of the chunks in the packet. 6230 */ 6231 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6232 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6233 SCTP_ERROR(ECONNABORTED)); 6234 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6235 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6236 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6237 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6238 return SCTP_IERROR_NO_DATA; 6239 } 6240 6241 chunk->data_accepted = 1; 6242 6243 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6244 * if we renege and the chunk arrives again. 6245 */ 6246 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6247 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6248 if (chunk->asoc) 6249 chunk->asoc->stats.iuodchunks++; 6250 } else { 6251 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6252 if (chunk->asoc) 6253 chunk->asoc->stats.iodchunks++; 6254 ordered = 1; 6255 } 6256 6257 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6258 * 6259 * If an endpoint receive a DATA chunk with an invalid stream 6260 * identifier, it shall acknowledge the reception of the DATA chunk 6261 * following the normal procedure, immediately send an ERROR chunk 6262 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6263 * and discard the DATA chunk. 6264 */ 6265 sid = ntohs(data_hdr->stream); 6266 if (sid >= asoc->c.sinit_max_instreams) { 6267 /* Mark tsn as received even though we drop it */ 6268 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6269 6270 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6271 &data_hdr->stream, 6272 sizeof(data_hdr->stream), 6273 sizeof(u16)); 6274 if (err) 6275 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6276 SCTP_CHUNK(err)); 6277 return SCTP_IERROR_BAD_STREAM; 6278 } 6279 6280 /* Check to see if the SSN is possible for this TSN. 6281 * The biggest gap we can record is 4K wide. Since SSNs wrap 6282 * at an unsigned short, there is no way that an SSN can 6283 * wrap and for a valid TSN. We can simply check if the current 6284 * SSN is smaller then the next expected one. If it is, it wrapped 6285 * and is invalid. 6286 */ 6287 ssn = ntohs(data_hdr->ssn); 6288 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6289 return SCTP_IERROR_PROTO_VIOLATION; 6290 } 6291 6292 /* Send the data up to the user. Note: Schedule the 6293 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6294 * chunk needs the updated rwnd. 6295 */ 6296 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6297 6298 return SCTP_IERROR_NO_ERROR; 6299 } 6300