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, 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, 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 kfree_skb(chunk->auth_chunk); 764 sctp_association_free(new_asoc); 765 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 766 } 767 768 /* set-up our fake chunk so that we can process it */ 769 auth.skb = chunk->auth_chunk; 770 auth.asoc = chunk->asoc; 771 auth.sctp_hdr = chunk->sctp_hdr; 772 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 773 sizeof(sctp_chunkhdr_t)); 774 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 775 auth.transport = chunk->transport; 776 777 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 778 779 /* We can now safely free the auth_chunk clone */ 780 kfree_skb(chunk->auth_chunk); 781 782 if (ret != SCTP_IERROR_NO_ERROR) { 783 sctp_association_free(new_asoc); 784 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 785 } 786 } 787 788 repl = sctp_make_cookie_ack(new_asoc, chunk); 789 if (!repl) 790 goto nomem_init; 791 792 /* RFC 2960 5.1 Normal Establishment of an Association 793 * 794 * D) IMPLEMENTATION NOTE: An implementation may choose to 795 * send the Communication Up notification to the SCTP user 796 * upon reception of a valid COOKIE ECHO chunk. 797 */ 798 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 799 new_asoc->c.sinit_num_ostreams, 800 new_asoc->c.sinit_max_instreams, 801 NULL, GFP_ATOMIC); 802 if (!ev) 803 goto nomem_ev; 804 805 /* Sockets API Draft Section 5.3.1.6 806 * When a peer sends a Adaptation Layer Indication parameter , SCTP 807 * delivers this notification to inform the application that of the 808 * peers requested adaptation layer. 809 */ 810 if (new_asoc->peer.adaptation_ind) { 811 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 812 GFP_ATOMIC); 813 if (!ai_ev) 814 goto nomem_aiev; 815 } 816 817 /* Add all the state machine commands now since we've created 818 * everything. This way we don't introduce memory corruptions 819 * during side-effect processing and correclty count established 820 * associations. 821 */ 822 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 823 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 824 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 825 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 826 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 827 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 828 829 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 830 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 831 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 832 833 /* This will send the COOKIE ACK */ 834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 835 836 /* Queue the ASSOC_CHANGE event */ 837 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 838 839 /* Send up the Adaptation Layer Indication event */ 840 if (ai_ev) 841 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 842 SCTP_ULPEVENT(ai_ev)); 843 844 return SCTP_DISPOSITION_CONSUME; 845 846 nomem_aiev: 847 sctp_ulpevent_free(ev); 848 nomem_ev: 849 sctp_chunk_free(repl); 850 nomem_init: 851 sctp_association_free(new_asoc); 852 nomem: 853 return SCTP_DISPOSITION_NOMEM; 854 } 855 856 /* 857 * Respond to a normal COOKIE ACK chunk. 858 * We are the side that is being asked for an association. 859 * 860 * RFC 2960 5.1 Normal Establishment of an Association 861 * 862 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 863 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 864 * timer. It may also notify its ULP about the successful 865 * establishment of the association with a Communication Up 866 * notification (see Section 10). 867 * 868 * Verification Tag: 869 * Inputs 870 * (endpoint, asoc, chunk) 871 * 872 * Outputs 873 * (asoc, reply_msg, msg_up, timers, counters) 874 * 875 * The return value is the disposition of the chunk. 876 */ 877 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 878 const struct sctp_endpoint *ep, 879 const struct sctp_association *asoc, 880 const sctp_subtype_t type, void *arg, 881 sctp_cmd_seq_t *commands) 882 { 883 struct sctp_chunk *chunk = arg; 884 struct sctp_ulpevent *ev; 885 886 if (!sctp_vtag_verify(chunk, asoc)) 887 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 888 889 /* Verify that the chunk length for the COOKIE-ACK is OK. 890 * If we don't do this, any bundled chunks may be junked. 891 */ 892 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 893 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 894 commands); 895 896 /* Reset init error count upon receipt of COOKIE-ACK, 897 * to avoid problems with the managemement of this 898 * counter in stale cookie situations when a transition back 899 * from the COOKIE-ECHOED state to the COOKIE-WAIT 900 * state is performed. 901 */ 902 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 903 904 /* RFC 2960 5.1 Normal Establishment of an Association 905 * 906 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 907 * from the COOKIE-ECHOED state to the ESTABLISHED state, 908 * stopping the T1-cookie timer. 909 */ 910 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 911 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 912 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 913 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 914 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 915 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 916 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 917 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 918 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 919 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 920 921 /* It may also notify its ULP about the successful 922 * establishment of the association with a Communication Up 923 * notification (see Section 10). 924 */ 925 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 926 0, asoc->c.sinit_num_ostreams, 927 asoc->c.sinit_max_instreams, 928 NULL, GFP_ATOMIC); 929 930 if (!ev) 931 goto nomem; 932 933 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 934 935 /* Sockets API Draft Section 5.3.1.6 936 * When a peer sends a Adaptation Layer Indication parameter , SCTP 937 * delivers this notification to inform the application that of the 938 * peers requested adaptation layer. 939 */ 940 if (asoc->peer.adaptation_ind) { 941 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 942 if (!ev) 943 goto nomem; 944 945 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 946 SCTP_ULPEVENT(ev)); 947 } 948 949 return SCTP_DISPOSITION_CONSUME; 950 nomem: 951 return SCTP_DISPOSITION_NOMEM; 952 } 953 954 /* Generate and sendout a heartbeat packet. */ 955 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 956 const struct sctp_association *asoc, 957 const sctp_subtype_t type, 958 void *arg, 959 sctp_cmd_seq_t *commands) 960 { 961 struct sctp_transport *transport = (struct sctp_transport *) arg; 962 struct sctp_chunk *reply; 963 964 /* Send a heartbeat to our peer. */ 965 reply = sctp_make_heartbeat(asoc, transport); 966 if (!reply) 967 return SCTP_DISPOSITION_NOMEM; 968 969 /* Set rto_pending indicating that an RTT measurement 970 * is started with this heartbeat chunk. 971 */ 972 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 973 SCTP_TRANSPORT(transport)); 974 975 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 976 return SCTP_DISPOSITION_CONSUME; 977 } 978 979 /* Generate a HEARTBEAT packet on the given transport. */ 980 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 981 const struct sctp_endpoint *ep, 982 const struct sctp_association *asoc, 983 const sctp_subtype_t type, 984 void *arg, 985 sctp_cmd_seq_t *commands) 986 { 987 struct sctp_transport *transport = (struct sctp_transport *) arg; 988 989 if (asoc->overall_error_count >= asoc->max_retrans) { 990 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 991 SCTP_ERROR(ETIMEDOUT)); 992 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 993 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 994 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 995 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 996 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 997 return SCTP_DISPOSITION_DELETE_TCB; 998 } 999 1000 /* Section 3.3.5. 1001 * The Sender-specific Heartbeat Info field should normally include 1002 * information about the sender's current time when this HEARTBEAT 1003 * chunk is sent and the destination transport address to which this 1004 * HEARTBEAT is sent (see Section 8.3). 1005 */ 1006 1007 if (transport->param_flags & SPP_HB_ENABLE) { 1008 if (SCTP_DISPOSITION_NOMEM == 1009 sctp_sf_heartbeat(ep, asoc, type, arg, 1010 commands)) 1011 return SCTP_DISPOSITION_NOMEM; 1012 1013 /* Set transport error counter and association error counter 1014 * when sending heartbeat. 1015 */ 1016 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1017 SCTP_TRANSPORT(transport)); 1018 } 1019 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1020 SCTP_TRANSPORT(transport)); 1021 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1022 SCTP_TRANSPORT(transport)); 1023 1024 return SCTP_DISPOSITION_CONSUME; 1025 } 1026 1027 /* 1028 * Process an heartbeat request. 1029 * 1030 * Section: 8.3 Path Heartbeat 1031 * The receiver of the HEARTBEAT should immediately respond with a 1032 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1033 * from the received HEARTBEAT chunk. 1034 * 1035 * Verification Tag: 8.5 Verification Tag [Normal verification] 1036 * When receiving an SCTP packet, the endpoint MUST ensure that the 1037 * value in the Verification Tag field of the received SCTP packet 1038 * matches its own Tag. If the received Verification Tag value does not 1039 * match the receiver's own tag value, the receiver shall silently 1040 * discard the packet and shall not process it any further except for 1041 * those cases listed in Section 8.5.1 below. 1042 * 1043 * Inputs 1044 * (endpoint, asoc, chunk) 1045 * 1046 * Outputs 1047 * (asoc, reply_msg, msg_up, timers, counters) 1048 * 1049 * The return value is the disposition of the chunk. 1050 */ 1051 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1052 const struct sctp_endpoint *ep, 1053 const struct sctp_association *asoc, 1054 const sctp_subtype_t type, 1055 void *arg, 1056 sctp_cmd_seq_t *commands) 1057 { 1058 sctp_paramhdr_t *param_hdr; 1059 struct sctp_chunk *chunk = arg; 1060 struct sctp_chunk *reply; 1061 size_t paylen = 0; 1062 1063 if (!sctp_vtag_verify(chunk, asoc)) 1064 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1065 1066 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1067 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1068 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1069 commands); 1070 1071 /* 8.3 The receiver of the HEARTBEAT should immediately 1072 * respond with a HEARTBEAT ACK that contains the Heartbeat 1073 * Information field copied from the received HEARTBEAT chunk. 1074 */ 1075 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1076 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr; 1077 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1078 1079 if (ntohs(param_hdr->length) > paylen) 1080 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1081 param_hdr, commands); 1082 1083 if (!pskb_pull(chunk->skb, paylen)) 1084 goto nomem; 1085 1086 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1087 if (!reply) 1088 goto nomem; 1089 1090 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1091 return SCTP_DISPOSITION_CONSUME; 1092 1093 nomem: 1094 return SCTP_DISPOSITION_NOMEM; 1095 } 1096 1097 /* 1098 * Process the returning HEARTBEAT ACK. 1099 * 1100 * Section: 8.3 Path Heartbeat 1101 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1102 * should clear the error counter of the destination transport 1103 * address to which the HEARTBEAT was sent, and mark the destination 1104 * transport address as active if it is not so marked. The endpoint may 1105 * optionally report to the upper layer when an inactive destination 1106 * address is marked as active due to the reception of the latest 1107 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1108 * clear the association overall error count as well (as defined 1109 * in section 8.1). 1110 * 1111 * The receiver of the HEARTBEAT ACK should also perform an RTT 1112 * measurement for that destination transport address using the time 1113 * value carried in the HEARTBEAT ACK chunk. 1114 * 1115 * Verification Tag: 8.5 Verification Tag [Normal verification] 1116 * 1117 * Inputs 1118 * (endpoint, asoc, chunk) 1119 * 1120 * Outputs 1121 * (asoc, reply_msg, msg_up, timers, counters) 1122 * 1123 * The return value is the disposition of the chunk. 1124 */ 1125 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1126 const struct sctp_endpoint *ep, 1127 const struct sctp_association *asoc, 1128 const sctp_subtype_t type, 1129 void *arg, 1130 sctp_cmd_seq_t *commands) 1131 { 1132 struct sctp_chunk *chunk = arg; 1133 union sctp_addr from_addr; 1134 struct sctp_transport *link; 1135 sctp_sender_hb_info_t *hbinfo; 1136 unsigned long max_interval; 1137 1138 if (!sctp_vtag_verify(chunk, asoc)) 1139 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1140 1141 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1142 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1143 sizeof(sctp_sender_hb_info_t))) 1144 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1145 commands); 1146 1147 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1148 /* Make sure that the length of the parameter is what we expect */ 1149 if (ntohs(hbinfo->param_hdr.length) != 1150 sizeof(sctp_sender_hb_info_t)) { 1151 return SCTP_DISPOSITION_DISCARD; 1152 } 1153 1154 from_addr = hbinfo->daddr; 1155 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1156 1157 /* This should never happen, but lets log it if so. */ 1158 if (unlikely(!link)) { 1159 if (from_addr.sa.sa_family == AF_INET6) { 1160 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1161 __func__, 1162 asoc, 1163 &from_addr.v6.sin6_addr); 1164 } else { 1165 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1166 __func__, 1167 asoc, 1168 &from_addr.v4.sin_addr.s_addr); 1169 } 1170 return SCTP_DISPOSITION_DISCARD; 1171 } 1172 1173 /* Validate the 64-bit random nonce. */ 1174 if (hbinfo->hb_nonce != link->hb_nonce) 1175 return SCTP_DISPOSITION_DISCARD; 1176 1177 max_interval = link->hbinterval + link->rto; 1178 1179 /* Check if the timestamp looks valid. */ 1180 if (time_after(hbinfo->sent_at, jiffies) || 1181 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1182 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1183 "for transport:%p\n", __func__, link); 1184 1185 return SCTP_DISPOSITION_DISCARD; 1186 } 1187 1188 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1189 * the HEARTBEAT should clear the error counter of the 1190 * destination transport address to which the HEARTBEAT was 1191 * sent and mark the destination transport address as active if 1192 * it is not so marked. 1193 */ 1194 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1195 1196 return SCTP_DISPOSITION_CONSUME; 1197 } 1198 1199 /* Helper function to send out an abort for the restart 1200 * condition. 1201 */ 1202 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1203 struct sctp_chunk *init, 1204 sctp_cmd_seq_t *commands) 1205 { 1206 int len; 1207 struct sctp_packet *pkt; 1208 union sctp_addr_param *addrparm; 1209 struct sctp_errhdr *errhdr; 1210 struct sctp_endpoint *ep; 1211 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1212 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1213 1214 /* Build the error on the stack. We are way to malloc crazy 1215 * throughout the code today. 1216 */ 1217 errhdr = (struct sctp_errhdr *)buffer; 1218 addrparm = (union sctp_addr_param *)errhdr->variable; 1219 1220 /* Copy into a parm format. */ 1221 len = af->to_addr_param(ssa, addrparm); 1222 len += sizeof(sctp_errhdr_t); 1223 1224 errhdr->cause = SCTP_ERROR_RESTART; 1225 errhdr->length = htons(len); 1226 1227 /* Assign to the control socket. */ 1228 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1229 1230 /* Association is NULL since this may be a restart attack and we 1231 * want to send back the attacker's vtag. 1232 */ 1233 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1234 1235 if (!pkt) 1236 goto out; 1237 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1238 1239 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1240 1241 /* Discard the rest of the inbound packet. */ 1242 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1243 1244 out: 1245 /* Even if there is no memory, treat as a failure so 1246 * the packet will get dropped. 1247 */ 1248 return 0; 1249 } 1250 1251 static bool list_has_sctp_addr(const struct list_head *list, 1252 union sctp_addr *ipaddr) 1253 { 1254 struct sctp_transport *addr; 1255 1256 list_for_each_entry(addr, list, transports) { 1257 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1258 return true; 1259 } 1260 1261 return false; 1262 } 1263 /* A restart is occurring, check to make sure no new addresses 1264 * are being added as we may be under a takeover attack. 1265 */ 1266 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1267 const struct sctp_association *asoc, 1268 struct sctp_chunk *init, 1269 sctp_cmd_seq_t *commands) 1270 { 1271 struct net *net = sock_net(new_asoc->base.sk); 1272 struct sctp_transport *new_addr; 1273 int ret = 1; 1274 1275 /* Implementor's Guide - Section 5.2.2 1276 * ... 1277 * Before responding the endpoint MUST check to see if the 1278 * unexpected INIT adds new addresses to the association. If new 1279 * addresses are added to the association, the endpoint MUST respond 1280 * with an ABORT.. 1281 */ 1282 1283 /* Search through all current addresses and make sure 1284 * we aren't adding any new ones. 1285 */ 1286 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1287 transports) { 1288 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1289 &new_addr->ipaddr)) { 1290 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1291 commands); 1292 ret = 0; 1293 break; 1294 } 1295 } 1296 1297 /* Return success if all addresses were found. */ 1298 return ret; 1299 } 1300 1301 /* Populate the verification/tie tags based on overlapping INIT 1302 * scenario. 1303 * 1304 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1305 */ 1306 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1307 const struct sctp_association *asoc) 1308 { 1309 switch (asoc->state) { 1310 1311 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1312 1313 case SCTP_STATE_COOKIE_WAIT: 1314 new_asoc->c.my_vtag = asoc->c.my_vtag; 1315 new_asoc->c.my_ttag = asoc->c.my_vtag; 1316 new_asoc->c.peer_ttag = 0; 1317 break; 1318 1319 case SCTP_STATE_COOKIE_ECHOED: 1320 new_asoc->c.my_vtag = asoc->c.my_vtag; 1321 new_asoc->c.my_ttag = asoc->c.my_vtag; 1322 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1323 break; 1324 1325 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1326 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1327 */ 1328 default: 1329 new_asoc->c.my_ttag = asoc->c.my_vtag; 1330 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1331 break; 1332 } 1333 1334 /* Other parameters for the endpoint SHOULD be copied from the 1335 * existing parameters of the association (e.g. number of 1336 * outbound streams) into the INIT ACK and cookie. 1337 */ 1338 new_asoc->rwnd = asoc->rwnd; 1339 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1340 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1341 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1342 } 1343 1344 /* 1345 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1346 * handling action. 1347 * 1348 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1349 * 1350 * Returns value representing action to be taken. These action values 1351 * correspond to Action/Description values in RFC 2960, Table 2. 1352 */ 1353 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1354 const struct sctp_association *asoc) 1355 { 1356 /* In this case, the peer may have restarted. */ 1357 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1358 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1359 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1360 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1361 return 'A'; 1362 1363 /* Collision case B. */ 1364 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1365 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1366 (0 == asoc->c.peer_vtag))) { 1367 return 'B'; 1368 } 1369 1370 /* Collision case D. */ 1371 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1372 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1373 return 'D'; 1374 1375 /* Collision case C. */ 1376 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1377 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1378 (0 == new_asoc->c.my_ttag) && 1379 (0 == new_asoc->c.peer_ttag)) 1380 return 'C'; 1381 1382 /* No match to any of the special cases; discard this packet. */ 1383 return 'E'; 1384 } 1385 1386 /* Common helper routine for both duplicate and simulataneous INIT 1387 * chunk handling. 1388 */ 1389 static sctp_disposition_t sctp_sf_do_unexpected_init( 1390 struct net *net, 1391 const struct sctp_endpoint *ep, 1392 const struct sctp_association *asoc, 1393 const sctp_subtype_t type, 1394 void *arg, sctp_cmd_seq_t *commands) 1395 { 1396 sctp_disposition_t retval; 1397 struct sctp_chunk *chunk = arg; 1398 struct sctp_chunk *repl; 1399 struct sctp_association *new_asoc; 1400 struct sctp_chunk *err_chunk; 1401 struct sctp_packet *packet; 1402 sctp_unrecognized_param_t *unk_param; 1403 int len; 1404 1405 /* 6.10 Bundling 1406 * An endpoint MUST NOT bundle INIT, INIT ACK or 1407 * SHUTDOWN COMPLETE with any other chunks. 1408 * 1409 * IG Section 2.11.2 1410 * Furthermore, we require that the receiver of an INIT chunk MUST 1411 * enforce these rules by silently discarding an arriving packet 1412 * with an INIT chunk that is bundled with other chunks. 1413 */ 1414 if (!chunk->singleton) 1415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1416 1417 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1418 * Tag. 1419 */ 1420 if (chunk->sctp_hdr->vtag != 0) 1421 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1422 1423 /* Make sure that the INIT chunk has a valid length. 1424 * In this case, we generate a protocol violation since we have 1425 * an association established. 1426 */ 1427 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1428 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1429 commands); 1430 /* Grab the INIT header. */ 1431 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1432 1433 /* Tag the variable length parameters. */ 1434 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1435 1436 /* Verify the INIT chunk before processing it. */ 1437 err_chunk = NULL; 1438 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 1439 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1440 &err_chunk)) { 1441 /* This chunk contains fatal error. It is to be discarded. 1442 * Send an ABORT, with causes if there is any. 1443 */ 1444 if (err_chunk) { 1445 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1446 (__u8 *)(err_chunk->chunk_hdr) + 1447 sizeof(sctp_chunkhdr_t), 1448 ntohs(err_chunk->chunk_hdr->length) - 1449 sizeof(sctp_chunkhdr_t)); 1450 1451 if (packet) { 1452 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1453 SCTP_PACKET(packet)); 1454 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1455 retval = SCTP_DISPOSITION_CONSUME; 1456 } else { 1457 retval = SCTP_DISPOSITION_NOMEM; 1458 } 1459 goto cleanup; 1460 } else { 1461 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1462 commands); 1463 } 1464 } 1465 1466 /* 1467 * Other parameters for the endpoint SHOULD be copied from the 1468 * existing parameters of the association (e.g. number of 1469 * outbound streams) into the INIT ACK and cookie. 1470 * FIXME: We are copying parameters from the endpoint not the 1471 * association. 1472 */ 1473 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1474 if (!new_asoc) 1475 goto nomem; 1476 1477 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1478 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1479 goto nomem; 1480 1481 /* In the outbound INIT ACK the endpoint MUST copy its current 1482 * Verification Tag and Peers Verification tag into a reserved 1483 * place (local tie-tag and per tie-tag) within the state cookie. 1484 */ 1485 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1486 (sctp_init_chunk_t *)chunk->chunk_hdr, 1487 GFP_ATOMIC)) 1488 goto nomem; 1489 1490 /* Make sure no new addresses are being added during the 1491 * restart. Do not do this check for COOKIE-WAIT state, 1492 * since there are no peer addresses to check against. 1493 * Upon return an ABORT will have been sent if needed. 1494 */ 1495 if (!sctp_state(asoc, COOKIE_WAIT)) { 1496 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1497 commands)) { 1498 retval = SCTP_DISPOSITION_CONSUME; 1499 goto nomem_retval; 1500 } 1501 } 1502 1503 sctp_tietags_populate(new_asoc, asoc); 1504 1505 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1506 1507 /* If there are errors need to be reported for unknown parameters, 1508 * make sure to reserve enough room in the INIT ACK for them. 1509 */ 1510 len = 0; 1511 if (err_chunk) { 1512 len = ntohs(err_chunk->chunk_hdr->length) - 1513 sizeof(sctp_chunkhdr_t); 1514 } 1515 1516 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1517 if (!repl) 1518 goto nomem; 1519 1520 /* If there are errors need to be reported for unknown parameters, 1521 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1522 * parameter. 1523 */ 1524 if (err_chunk) { 1525 /* Get the "Unrecognized parameter" parameter(s) out of the 1526 * ERROR chunk generated by sctp_verify_init(). Since the 1527 * error cause code for "unknown parameter" and the 1528 * "Unrecognized parameter" type is the same, we can 1529 * construct the parameters in INIT ACK by copying the 1530 * ERROR causes over. 1531 */ 1532 unk_param = (sctp_unrecognized_param_t *) 1533 ((__u8 *)(err_chunk->chunk_hdr) + 1534 sizeof(sctp_chunkhdr_t)); 1535 /* Replace the cause code with the "Unrecognized parameter" 1536 * parameter type. 1537 */ 1538 sctp_addto_chunk(repl, len, unk_param); 1539 } 1540 1541 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1542 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1543 1544 /* 1545 * Note: After sending out INIT ACK with the State Cookie parameter, 1546 * "Z" MUST NOT allocate any resources for this new association. 1547 * Otherwise, "Z" will be vulnerable to resource attacks. 1548 */ 1549 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1550 retval = SCTP_DISPOSITION_CONSUME; 1551 1552 return retval; 1553 1554 nomem: 1555 retval = SCTP_DISPOSITION_NOMEM; 1556 nomem_retval: 1557 if (new_asoc) 1558 sctp_association_free(new_asoc); 1559 cleanup: 1560 if (err_chunk) 1561 sctp_chunk_free(err_chunk); 1562 return retval; 1563 } 1564 1565 /* 1566 * Handle simultaneous INIT. 1567 * This means we started an INIT and then we got an INIT request from 1568 * our peer. 1569 * 1570 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1571 * This usually indicates an initialization collision, i.e., each 1572 * endpoint is attempting, at about the same time, to establish an 1573 * association with the other endpoint. 1574 * 1575 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1576 * endpoint MUST respond with an INIT ACK using the same parameters it 1577 * sent in its original INIT chunk (including its Verification Tag, 1578 * unchanged). These original parameters are combined with those from the 1579 * newly received INIT chunk. The endpoint shall also generate a State 1580 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1581 * INIT to calculate the State Cookie. 1582 * 1583 * After that, the endpoint MUST NOT change its state, the T1-init 1584 * timer shall be left running and the corresponding TCB MUST NOT be 1585 * destroyed. The normal procedures for handling State Cookies when 1586 * a TCB exists will resolve the duplicate INITs to a single association. 1587 * 1588 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1589 * its Tie-Tags with the Tag information of itself and its peer (see 1590 * section 5.2.2 for a description of the Tie-Tags). 1591 * 1592 * Verification Tag: Not explicit, but an INIT can not have a valid 1593 * verification tag, so we skip the check. 1594 * 1595 * Inputs 1596 * (endpoint, asoc, chunk) 1597 * 1598 * Outputs 1599 * (asoc, reply_msg, msg_up, timers, counters) 1600 * 1601 * The return value is the disposition of the chunk. 1602 */ 1603 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1604 const struct sctp_endpoint *ep, 1605 const struct sctp_association *asoc, 1606 const sctp_subtype_t type, 1607 void *arg, 1608 sctp_cmd_seq_t *commands) 1609 { 1610 /* Call helper to do the real work for both simulataneous and 1611 * duplicate INIT chunk handling. 1612 */ 1613 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1614 } 1615 1616 /* 1617 * Handle duplicated INIT messages. These are usually delayed 1618 * restransmissions. 1619 * 1620 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1621 * COOKIE-ECHOED and COOKIE-WAIT 1622 * 1623 * Unless otherwise stated, upon reception of an unexpected INIT for 1624 * this association, the endpoint shall generate an INIT ACK with a 1625 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1626 * current Verification Tag and peer's Verification Tag into a reserved 1627 * place within the state cookie. We shall refer to these locations as 1628 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1629 * containing this INIT ACK MUST carry a Verification Tag value equal to 1630 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1631 * MUST contain a new Initiation Tag (randomly generated see Section 1632 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1633 * existing parameters of the association (e.g. number of outbound 1634 * streams) into the INIT ACK and cookie. 1635 * 1636 * After sending out the INIT ACK, the endpoint shall take no further 1637 * actions, i.e., the existing association, including its current state, 1638 * and the corresponding TCB MUST NOT be changed. 1639 * 1640 * Note: Only when a TCB exists and the association is not in a COOKIE- 1641 * WAIT state are the Tie-Tags populated. For a normal association INIT 1642 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1643 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1644 * State Cookie are populated as specified in section 5.2.1. 1645 * 1646 * Verification Tag: Not specified, but an INIT has no way of knowing 1647 * what the verification tag could be, so we ignore it. 1648 * 1649 * Inputs 1650 * (endpoint, asoc, chunk) 1651 * 1652 * Outputs 1653 * (asoc, reply_msg, msg_up, timers, counters) 1654 * 1655 * The return value is the disposition of the chunk. 1656 */ 1657 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1658 const struct sctp_endpoint *ep, 1659 const struct sctp_association *asoc, 1660 const sctp_subtype_t type, 1661 void *arg, 1662 sctp_cmd_seq_t *commands) 1663 { 1664 /* Call helper to do the real work for both simulataneous and 1665 * duplicate INIT chunk handling. 1666 */ 1667 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1668 } 1669 1670 1671 /* 1672 * Unexpected INIT-ACK handler. 1673 * 1674 * Section 5.2.3 1675 * If an INIT ACK received by an endpoint in any state other than the 1676 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1677 * An unexpected INIT ACK usually indicates the processing of an old or 1678 * duplicated INIT chunk. 1679 */ 1680 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1681 const struct sctp_endpoint *ep, 1682 const struct sctp_association *asoc, 1683 const sctp_subtype_t type, 1684 void *arg, sctp_cmd_seq_t *commands) 1685 { 1686 /* Per the above section, we'll discard the chunk if we have an 1687 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1688 */ 1689 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1690 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1691 else 1692 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1693 } 1694 1695 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1696 * 1697 * Section 5.2.4 1698 * A) In this case, the peer may have restarted. 1699 */ 1700 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1701 const struct sctp_endpoint *ep, 1702 const struct sctp_association *asoc, 1703 struct sctp_chunk *chunk, 1704 sctp_cmd_seq_t *commands, 1705 struct sctp_association *new_asoc) 1706 { 1707 sctp_init_chunk_t *peer_init; 1708 struct sctp_ulpevent *ev; 1709 struct sctp_chunk *repl; 1710 struct sctp_chunk *err; 1711 sctp_disposition_t disposition; 1712 1713 /* new_asoc is a brand-new association, so these are not yet 1714 * side effects--it is safe to run them here. 1715 */ 1716 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1717 1718 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1719 GFP_ATOMIC)) 1720 goto nomem; 1721 1722 /* Make sure no new addresses are being added during the 1723 * restart. Though this is a pretty complicated attack 1724 * since you'd have to get inside the cookie. 1725 */ 1726 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1727 return SCTP_DISPOSITION_CONSUME; 1728 } 1729 1730 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1731 * the peer has restarted (Action A), it MUST NOT setup a new 1732 * association but instead resend the SHUTDOWN ACK and send an ERROR 1733 * chunk with a "Cookie Received while Shutting Down" error cause to 1734 * its peer. 1735 */ 1736 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1737 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1738 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1739 chunk, commands); 1740 if (SCTP_DISPOSITION_NOMEM == disposition) 1741 goto nomem; 1742 1743 err = sctp_make_op_error(asoc, chunk, 1744 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1745 NULL, 0, 0); 1746 if (err) 1747 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1748 SCTP_CHUNK(err)); 1749 1750 return SCTP_DISPOSITION_CONSUME; 1751 } 1752 1753 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1754 * data. Consider the optional choice of resending of this data. 1755 */ 1756 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1757 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1758 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1759 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1760 1761 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1762 * and ASCONF-ACK cache. 1763 */ 1764 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1765 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1766 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1767 1768 repl = sctp_make_cookie_ack(new_asoc, chunk); 1769 if (!repl) 1770 goto nomem; 1771 1772 /* Report association restart to upper layer. */ 1773 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1774 new_asoc->c.sinit_num_ostreams, 1775 new_asoc->c.sinit_max_instreams, 1776 NULL, GFP_ATOMIC); 1777 if (!ev) 1778 goto nomem_ev; 1779 1780 /* Update the content of current association. */ 1781 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1782 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1783 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1784 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1785 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1786 return SCTP_DISPOSITION_CONSUME; 1787 1788 nomem_ev: 1789 sctp_chunk_free(repl); 1790 nomem: 1791 return SCTP_DISPOSITION_NOMEM; 1792 } 1793 1794 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1795 * 1796 * Section 5.2.4 1797 * B) In this case, both sides may be attempting to start an association 1798 * at about the same time but the peer endpoint started its INIT 1799 * after responding to the local endpoint's INIT 1800 */ 1801 /* This case represents an initialization collision. */ 1802 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1803 const struct sctp_endpoint *ep, 1804 const struct sctp_association *asoc, 1805 struct sctp_chunk *chunk, 1806 sctp_cmd_seq_t *commands, 1807 struct sctp_association *new_asoc) 1808 { 1809 sctp_init_chunk_t *peer_init; 1810 struct sctp_chunk *repl; 1811 1812 /* new_asoc is a brand-new association, so these are not yet 1813 * side effects--it is safe to run them here. 1814 */ 1815 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1816 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1817 GFP_ATOMIC)) 1818 goto nomem; 1819 1820 /* Update the content of current association. */ 1821 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1822 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1823 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1824 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1825 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1826 1827 repl = sctp_make_cookie_ack(new_asoc, chunk); 1828 if (!repl) 1829 goto nomem; 1830 1831 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1832 1833 /* RFC 2960 5.1 Normal Establishment of an Association 1834 * 1835 * D) IMPLEMENTATION NOTE: An implementation may choose to 1836 * send the Communication Up notification to the SCTP user 1837 * upon reception of a valid COOKIE ECHO chunk. 1838 * 1839 * Sadly, this needs to be implemented as a side-effect, because 1840 * we are not guaranteed to have set the association id of the real 1841 * association and so these notifications need to be delayed until 1842 * the association id is allocated. 1843 */ 1844 1845 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1846 1847 /* Sockets API Draft Section 5.3.1.6 1848 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1849 * delivers this notification to inform the application that of the 1850 * peers requested adaptation layer. 1851 * 1852 * This also needs to be done as a side effect for the same reason as 1853 * above. 1854 */ 1855 if (asoc->peer.adaptation_ind) 1856 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1857 1858 return SCTP_DISPOSITION_CONSUME; 1859 1860 nomem: 1861 return SCTP_DISPOSITION_NOMEM; 1862 } 1863 1864 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1865 * 1866 * Section 5.2.4 1867 * C) In this case, the local endpoint's cookie has arrived late. 1868 * Before it arrived, the local endpoint sent an INIT and received an 1869 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1870 * but a new tag of its own. 1871 */ 1872 /* This case represents an initialization collision. */ 1873 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1874 const struct sctp_endpoint *ep, 1875 const struct sctp_association *asoc, 1876 struct sctp_chunk *chunk, 1877 sctp_cmd_seq_t *commands, 1878 struct sctp_association *new_asoc) 1879 { 1880 /* The cookie should be silently discarded. 1881 * The endpoint SHOULD NOT change states and should leave 1882 * any timers running. 1883 */ 1884 return SCTP_DISPOSITION_DISCARD; 1885 } 1886 1887 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1888 * 1889 * Section 5.2.4 1890 * 1891 * D) When both local and remote tags match the endpoint should always 1892 * enter the ESTABLISHED state, if it has not already done so. 1893 */ 1894 /* This case represents an initialization collision. */ 1895 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1896 const struct sctp_endpoint *ep, 1897 const struct sctp_association *asoc, 1898 struct sctp_chunk *chunk, 1899 sctp_cmd_seq_t *commands, 1900 struct sctp_association *new_asoc) 1901 { 1902 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1903 struct sctp_chunk *repl; 1904 1905 /* Clarification from Implementor's Guide: 1906 * D) When both local and remote tags match the endpoint should 1907 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1908 * It should stop any cookie timer that may be running and send 1909 * a COOKIE ACK. 1910 */ 1911 1912 /* Don't accidentally move back into established state. */ 1913 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1914 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1915 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1916 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1917 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1918 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1919 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1920 SCTP_NULL()); 1921 1922 /* RFC 2960 5.1 Normal Establishment of an Association 1923 * 1924 * D) IMPLEMENTATION NOTE: An implementation may choose 1925 * to send the Communication Up notification to the 1926 * SCTP user upon reception of a valid COOKIE 1927 * ECHO chunk. 1928 */ 1929 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1930 SCTP_COMM_UP, 0, 1931 asoc->c.sinit_num_ostreams, 1932 asoc->c.sinit_max_instreams, 1933 NULL, GFP_ATOMIC); 1934 if (!ev) 1935 goto nomem; 1936 1937 /* Sockets API Draft Section 5.3.1.6 1938 * When a peer sends a Adaptation Layer Indication parameter, 1939 * SCTP delivers this notification to inform the application 1940 * that of the peers requested adaptation layer. 1941 */ 1942 if (asoc->peer.adaptation_ind) { 1943 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1944 GFP_ATOMIC); 1945 if (!ai_ev) 1946 goto nomem; 1947 1948 } 1949 } 1950 1951 repl = sctp_make_cookie_ack(new_asoc, chunk); 1952 if (!repl) 1953 goto nomem; 1954 1955 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1956 1957 if (ev) 1958 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1959 SCTP_ULPEVENT(ev)); 1960 if (ai_ev) 1961 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1962 SCTP_ULPEVENT(ai_ev)); 1963 1964 return SCTP_DISPOSITION_CONSUME; 1965 1966 nomem: 1967 if (ai_ev) 1968 sctp_ulpevent_free(ai_ev); 1969 if (ev) 1970 sctp_ulpevent_free(ev); 1971 return SCTP_DISPOSITION_NOMEM; 1972 } 1973 1974 /* 1975 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1976 * chunk was retransmitted and then delayed in the network. 1977 * 1978 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1979 * 1980 * Verification Tag: None. Do cookie validation. 1981 * 1982 * Inputs 1983 * (endpoint, asoc, chunk) 1984 * 1985 * Outputs 1986 * (asoc, reply_msg, msg_up, timers, counters) 1987 * 1988 * The return value is the disposition of the chunk. 1989 */ 1990 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 1991 const struct sctp_endpoint *ep, 1992 const struct sctp_association *asoc, 1993 const sctp_subtype_t type, 1994 void *arg, 1995 sctp_cmd_seq_t *commands) 1996 { 1997 sctp_disposition_t retval; 1998 struct sctp_chunk *chunk = arg; 1999 struct sctp_association *new_asoc; 2000 int error = 0; 2001 char action; 2002 struct sctp_chunk *err_chk_p; 2003 2004 /* Make sure that the chunk has a valid length from the protocol 2005 * perspective. In this case check to make sure we have at least 2006 * enough for the chunk header. Cookie length verification is 2007 * done later. 2008 */ 2009 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2010 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2011 commands); 2012 2013 /* "Decode" the chunk. We have no optional parameters so we 2014 * are in good shape. 2015 */ 2016 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2017 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2018 sizeof(sctp_chunkhdr_t))) 2019 goto nomem; 2020 2021 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2022 * of a duplicate COOKIE ECHO match the Verification Tags of the 2023 * current association, consider the State Cookie valid even if 2024 * the lifespan is exceeded. 2025 */ 2026 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2027 &err_chk_p); 2028 2029 /* FIXME: 2030 * If the re-build failed, what is the proper error path 2031 * from here? 2032 * 2033 * [We should abort the association. --piggy] 2034 */ 2035 if (!new_asoc) { 2036 /* FIXME: Several errors are possible. A bad cookie should 2037 * be silently discarded, but think about logging it too. 2038 */ 2039 switch (error) { 2040 case -SCTP_IERROR_NOMEM: 2041 goto nomem; 2042 2043 case -SCTP_IERROR_STALE_COOKIE: 2044 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2045 err_chk_p); 2046 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2047 case -SCTP_IERROR_BAD_SIG: 2048 default: 2049 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2050 } 2051 } 2052 2053 /* Compare the tie_tag in cookie with the verification tag of 2054 * current association. 2055 */ 2056 action = sctp_tietags_compare(new_asoc, asoc); 2057 2058 switch (action) { 2059 case 'A': /* Association restart. */ 2060 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2061 new_asoc); 2062 break; 2063 2064 case 'B': /* Collision case B. */ 2065 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2066 new_asoc); 2067 break; 2068 2069 case 'C': /* Collision case C. */ 2070 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2071 new_asoc); 2072 break; 2073 2074 case 'D': /* Collision case D. */ 2075 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2076 new_asoc); 2077 break; 2078 2079 default: /* Discard packet for all others. */ 2080 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2081 break; 2082 } 2083 2084 /* Delete the tempory new association. */ 2085 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2086 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2087 2088 /* Restore association pointer to provide SCTP command interpeter 2089 * with a valid context in case it needs to manipulate 2090 * the queues */ 2091 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2092 SCTP_ASOC((struct sctp_association *)asoc)); 2093 2094 return retval; 2095 2096 nomem: 2097 return SCTP_DISPOSITION_NOMEM; 2098 } 2099 2100 /* 2101 * Process an ABORT. (SHUTDOWN-PENDING state) 2102 * 2103 * See sctp_sf_do_9_1_abort(). 2104 */ 2105 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2106 struct net *net, 2107 const struct sctp_endpoint *ep, 2108 const struct sctp_association *asoc, 2109 const sctp_subtype_t type, 2110 void *arg, 2111 sctp_cmd_seq_t *commands) 2112 { 2113 struct sctp_chunk *chunk = arg; 2114 2115 if (!sctp_vtag_verify_either(chunk, asoc)) 2116 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2117 2118 /* Make sure that the ABORT chunk has a valid length. 2119 * Since this is an ABORT chunk, we have to discard it 2120 * because of the following text: 2121 * RFC 2960, Section 3.3.7 2122 * If an endpoint receives an ABORT with a format error or for an 2123 * association that doesn't exist, it MUST silently discard it. 2124 * Because the length is "invalid", we can't really discard just 2125 * as we do not know its true length. So, to be safe, discard the 2126 * packet. 2127 */ 2128 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2129 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2130 2131 /* ADD-IP: Special case for ABORT chunks 2132 * F4) One special consideration is that ABORT Chunks arriving 2133 * destined to the IP address being deleted MUST be 2134 * ignored (see Section 5.3.1 for further details). 2135 */ 2136 if (SCTP_ADDR_DEL == 2137 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2138 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2139 2140 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2141 } 2142 2143 /* 2144 * Process an ABORT. (SHUTDOWN-SENT state) 2145 * 2146 * See sctp_sf_do_9_1_abort(). 2147 */ 2148 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2149 const struct sctp_endpoint *ep, 2150 const struct sctp_association *asoc, 2151 const sctp_subtype_t type, 2152 void *arg, 2153 sctp_cmd_seq_t *commands) 2154 { 2155 struct sctp_chunk *chunk = arg; 2156 2157 if (!sctp_vtag_verify_either(chunk, asoc)) 2158 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2159 2160 /* Make sure that the ABORT chunk has a valid length. 2161 * Since this is an ABORT chunk, we have to discard it 2162 * because of the following text: 2163 * RFC 2960, Section 3.3.7 2164 * If an endpoint receives an ABORT with a format error or for an 2165 * association that doesn't exist, it MUST silently discard it. 2166 * Because the length is "invalid", we can't really discard just 2167 * as we do not know its true length. So, to be safe, discard the 2168 * packet. 2169 */ 2170 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2171 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2172 2173 /* ADD-IP: Special case for ABORT chunks 2174 * F4) One special consideration is that ABORT Chunks arriving 2175 * destined to the IP address being deleted MUST be 2176 * ignored (see Section 5.3.1 for further details). 2177 */ 2178 if (SCTP_ADDR_DEL == 2179 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2180 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2181 2182 /* Stop the T2-shutdown timer. */ 2183 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2184 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2185 2186 /* Stop the T5-shutdown guard timer. */ 2187 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2188 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2189 2190 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2191 } 2192 2193 /* 2194 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2195 * 2196 * See sctp_sf_do_9_1_abort(). 2197 */ 2198 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2199 struct net *net, 2200 const struct sctp_endpoint *ep, 2201 const struct sctp_association *asoc, 2202 const sctp_subtype_t type, 2203 void *arg, 2204 sctp_cmd_seq_t *commands) 2205 { 2206 /* The same T2 timer, so we should be able to use 2207 * common function with the SHUTDOWN-SENT state. 2208 */ 2209 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2210 } 2211 2212 /* 2213 * Handle an Error received in COOKIE_ECHOED state. 2214 * 2215 * Only handle the error type of stale COOKIE Error, the other errors will 2216 * be ignored. 2217 * 2218 * Inputs 2219 * (endpoint, asoc, chunk) 2220 * 2221 * Outputs 2222 * (asoc, reply_msg, msg_up, timers, counters) 2223 * 2224 * The return value is the disposition of the chunk. 2225 */ 2226 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2227 const struct sctp_endpoint *ep, 2228 const struct sctp_association *asoc, 2229 const sctp_subtype_t type, 2230 void *arg, 2231 sctp_cmd_seq_t *commands) 2232 { 2233 struct sctp_chunk *chunk = arg; 2234 sctp_errhdr_t *err; 2235 2236 if (!sctp_vtag_verify(chunk, asoc)) 2237 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2238 2239 /* Make sure that the ERROR chunk has a valid length. 2240 * The parameter walking depends on this as well. 2241 */ 2242 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2243 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2244 commands); 2245 2246 /* Process the error here */ 2247 /* FUTURE FIXME: When PR-SCTP related and other optional 2248 * parms are emitted, this will have to change to handle multiple 2249 * errors. 2250 */ 2251 sctp_walk_errors(err, chunk->chunk_hdr) { 2252 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2253 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2254 arg, commands); 2255 } 2256 2257 /* It is possible to have malformed error causes, and that 2258 * will cause us to end the walk early. However, since 2259 * we are discarding the packet, there should be no adverse 2260 * affects. 2261 */ 2262 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2263 } 2264 2265 /* 2266 * Handle a Stale COOKIE Error 2267 * 2268 * Section: 5.2.6 Handle Stale COOKIE Error 2269 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2270 * one of the following three alternatives. 2271 * ... 2272 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2273 * Preservative parameter requesting an extension to the lifetime of 2274 * the State Cookie. When calculating the time extension, an 2275 * implementation SHOULD use the RTT information measured based on the 2276 * previous COOKIE ECHO / ERROR exchange, and should add no more 2277 * than 1 second beyond the measured RTT, due to long State Cookie 2278 * lifetimes making the endpoint more subject to a replay attack. 2279 * 2280 * Verification Tag: Not explicit, but safe to ignore. 2281 * 2282 * Inputs 2283 * (endpoint, asoc, chunk) 2284 * 2285 * Outputs 2286 * (asoc, reply_msg, msg_up, timers, counters) 2287 * 2288 * The return value is the disposition of the chunk. 2289 */ 2290 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2291 const struct sctp_endpoint *ep, 2292 const struct sctp_association *asoc, 2293 const sctp_subtype_t type, 2294 void *arg, 2295 sctp_cmd_seq_t *commands) 2296 { 2297 struct sctp_chunk *chunk = arg; 2298 time_t stale; 2299 sctp_cookie_preserve_param_t bht; 2300 sctp_errhdr_t *err; 2301 struct sctp_chunk *reply; 2302 struct sctp_bind_addr *bp; 2303 int attempts = asoc->init_err_counter + 1; 2304 2305 if (attempts > asoc->max_init_attempts) { 2306 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2307 SCTP_ERROR(ETIMEDOUT)); 2308 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2309 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2310 return SCTP_DISPOSITION_DELETE_TCB; 2311 } 2312 2313 err = (sctp_errhdr_t *)(chunk->skb->data); 2314 2315 /* When calculating the time extension, an implementation 2316 * SHOULD use the RTT information measured based on the 2317 * previous COOKIE ECHO / ERROR exchange, and should add no 2318 * more than 1 second beyond the measured RTT, due to long 2319 * State Cookie lifetimes making the endpoint more subject to 2320 * a replay attack. 2321 * Measure of Staleness's unit is usec. (1/1000000 sec) 2322 * Suggested Cookie Life-span Increment's unit is msec. 2323 * (1/1000 sec) 2324 * In general, if you use the suggested cookie life, the value 2325 * found in the field of measure of staleness should be doubled 2326 * to give ample time to retransmit the new cookie and thus 2327 * yield a higher probability of success on the reattempt. 2328 */ 2329 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2330 stale = (stale * 2) / 1000; 2331 2332 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2333 bht.param_hdr.length = htons(sizeof(bht)); 2334 bht.lifespan_increment = htonl(stale); 2335 2336 /* Build that new INIT chunk. */ 2337 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2338 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2339 if (!reply) 2340 goto nomem; 2341 2342 sctp_addto_chunk(reply, sizeof(bht), &bht); 2343 2344 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2345 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2346 2347 /* Stop pending T3-rtx and heartbeat timers */ 2348 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2349 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2350 2351 /* Delete non-primary peer ip addresses since we are transitioning 2352 * back to the COOKIE-WAIT state 2353 */ 2354 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2355 2356 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2357 * resend 2358 */ 2359 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2360 SCTP_TRANSPORT(asoc->peer.primary_path)); 2361 2362 /* Cast away the const modifier, as we want to just 2363 * rerun it through as a sideffect. 2364 */ 2365 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2366 2367 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2368 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2369 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2370 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2371 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2372 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2373 2374 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2375 2376 return SCTP_DISPOSITION_CONSUME; 2377 2378 nomem: 2379 return SCTP_DISPOSITION_NOMEM; 2380 } 2381 2382 /* 2383 * Process an ABORT. 2384 * 2385 * Section: 9.1 2386 * After checking the Verification Tag, the receiving endpoint shall 2387 * remove the association from its record, and shall report the 2388 * termination to its upper layer. 2389 * 2390 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2391 * B) Rules for packet carrying ABORT: 2392 * 2393 * - The endpoint shall always fill in the Verification Tag field of the 2394 * outbound packet with the destination endpoint's tag value if it 2395 * is known. 2396 * 2397 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2398 * MUST follow the procedure described in Section 8.4. 2399 * 2400 * - The receiver MUST accept the packet if the Verification Tag 2401 * matches either its own tag, OR the tag of its peer. Otherwise, the 2402 * receiver MUST silently discard the packet and take no further 2403 * action. 2404 * 2405 * Inputs 2406 * (endpoint, asoc, chunk) 2407 * 2408 * Outputs 2409 * (asoc, reply_msg, msg_up, timers, counters) 2410 * 2411 * The return value is the disposition of the chunk. 2412 */ 2413 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2414 const struct sctp_endpoint *ep, 2415 const struct sctp_association *asoc, 2416 const sctp_subtype_t type, 2417 void *arg, 2418 sctp_cmd_seq_t *commands) 2419 { 2420 struct sctp_chunk *chunk = arg; 2421 2422 if (!sctp_vtag_verify_either(chunk, asoc)) 2423 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2424 2425 /* Make sure that the ABORT chunk has a valid length. 2426 * Since this is an ABORT chunk, we have to discard it 2427 * because of the following text: 2428 * RFC 2960, Section 3.3.7 2429 * If an endpoint receives an ABORT with a format error or for an 2430 * association that doesn't exist, it MUST silently discard it. 2431 * Because the length is "invalid", we can't really discard just 2432 * as we do not know its true length. So, to be safe, discard the 2433 * packet. 2434 */ 2435 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2436 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2437 2438 /* ADD-IP: Special case for ABORT chunks 2439 * F4) One special consideration is that ABORT Chunks arriving 2440 * destined to the IP address being deleted MUST be 2441 * ignored (see Section 5.3.1 for further details). 2442 */ 2443 if (SCTP_ADDR_DEL == 2444 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2445 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2446 2447 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2448 } 2449 2450 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2451 const struct sctp_endpoint *ep, 2452 const struct sctp_association *asoc, 2453 const sctp_subtype_t type, 2454 void *arg, 2455 sctp_cmd_seq_t *commands) 2456 { 2457 struct sctp_chunk *chunk = arg; 2458 unsigned int len; 2459 __be16 error = SCTP_ERROR_NO_ERROR; 2460 2461 /* See if we have an error cause code in the chunk. */ 2462 len = ntohs(chunk->chunk_hdr->length); 2463 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2464 2465 sctp_errhdr_t *err; 2466 sctp_walk_errors(err, chunk->chunk_hdr); 2467 if ((void *)err != (void *)chunk->chunk_end) 2468 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2469 2470 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2471 } 2472 2473 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2474 /* ASSOC_FAILED will DELETE_TCB. */ 2475 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2476 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2477 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2478 2479 return SCTP_DISPOSITION_ABORT; 2480 } 2481 2482 /* 2483 * Process an ABORT. (COOKIE-WAIT state) 2484 * 2485 * See sctp_sf_do_9_1_abort() above. 2486 */ 2487 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2488 const struct sctp_endpoint *ep, 2489 const struct sctp_association *asoc, 2490 const sctp_subtype_t type, 2491 void *arg, 2492 sctp_cmd_seq_t *commands) 2493 { 2494 struct sctp_chunk *chunk = arg; 2495 unsigned int len; 2496 __be16 error = SCTP_ERROR_NO_ERROR; 2497 2498 if (!sctp_vtag_verify_either(chunk, asoc)) 2499 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2500 2501 /* Make sure that the ABORT chunk has a valid length. 2502 * Since this is an ABORT chunk, we have to discard it 2503 * because of the following text: 2504 * RFC 2960, Section 3.3.7 2505 * If an endpoint receives an ABORT with a format error or for an 2506 * association that doesn't exist, it MUST silently discard it. 2507 * Because the length is "invalid", we can't really discard just 2508 * as we do not know its true length. So, to be safe, discard the 2509 * packet. 2510 */ 2511 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2512 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2513 2514 /* See if we have an error cause code in the chunk. */ 2515 len = ntohs(chunk->chunk_hdr->length); 2516 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2517 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2518 2519 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2520 chunk->transport); 2521 } 2522 2523 /* 2524 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2525 */ 2526 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2527 const struct sctp_endpoint *ep, 2528 const struct sctp_association *asoc, 2529 const sctp_subtype_t type, 2530 void *arg, 2531 sctp_cmd_seq_t *commands) 2532 { 2533 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2534 ENOPROTOOPT, asoc, 2535 (struct sctp_transport *)arg); 2536 } 2537 2538 /* 2539 * Process an ABORT. (COOKIE-ECHOED state) 2540 */ 2541 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2542 const struct sctp_endpoint *ep, 2543 const struct sctp_association *asoc, 2544 const sctp_subtype_t type, 2545 void *arg, 2546 sctp_cmd_seq_t *commands) 2547 { 2548 /* There is a single T1 timer, so we should be able to use 2549 * common function with the COOKIE-WAIT state. 2550 */ 2551 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2552 } 2553 2554 /* 2555 * Stop T1 timer and abort association with "INIT failed". 2556 * 2557 * This is common code called by several sctp_sf_*_abort() functions above. 2558 */ 2559 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2560 sctp_cmd_seq_t *commands, 2561 __be16 error, int sk_err, 2562 const struct sctp_association *asoc, 2563 struct sctp_transport *transport) 2564 { 2565 pr_debug("%s: ABORT received (INIT)\n", __func__); 2566 2567 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2568 SCTP_STATE(SCTP_STATE_CLOSED)); 2569 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2570 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2571 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2572 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2573 /* CMD_INIT_FAILED will DELETE_TCB. */ 2574 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2575 SCTP_PERR(error)); 2576 2577 return SCTP_DISPOSITION_ABORT; 2578 } 2579 2580 /* 2581 * sctp_sf_do_9_2_shut 2582 * 2583 * Section: 9.2 2584 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2585 * - enter the SHUTDOWN-RECEIVED state, 2586 * 2587 * - stop accepting new data from its SCTP user 2588 * 2589 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2590 * that all its outstanding DATA chunks have been received by the 2591 * SHUTDOWN sender. 2592 * 2593 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2594 * send a SHUTDOWN in response to a ULP request. And should discard 2595 * subsequent SHUTDOWN chunks. 2596 * 2597 * If there are still outstanding DATA chunks left, the SHUTDOWN 2598 * receiver shall continue to follow normal data transmission 2599 * procedures defined in Section 6 until all outstanding DATA chunks 2600 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2601 * new data from its SCTP user. 2602 * 2603 * Verification Tag: 8.5 Verification Tag [Normal verification] 2604 * 2605 * Inputs 2606 * (endpoint, asoc, chunk) 2607 * 2608 * Outputs 2609 * (asoc, reply_msg, msg_up, timers, counters) 2610 * 2611 * The return value is the disposition of the chunk. 2612 */ 2613 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2614 const struct sctp_endpoint *ep, 2615 const struct sctp_association *asoc, 2616 const sctp_subtype_t type, 2617 void *arg, 2618 sctp_cmd_seq_t *commands) 2619 { 2620 struct sctp_chunk *chunk = arg; 2621 sctp_shutdownhdr_t *sdh; 2622 sctp_disposition_t disposition; 2623 struct sctp_ulpevent *ev; 2624 __u32 ctsn; 2625 2626 if (!sctp_vtag_verify(chunk, asoc)) 2627 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2628 2629 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2630 if (!sctp_chunk_length_valid(chunk, 2631 sizeof(struct sctp_shutdown_chunk_t))) 2632 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2633 commands); 2634 2635 /* Convert the elaborate header. */ 2636 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2637 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2638 chunk->subh.shutdown_hdr = sdh; 2639 ctsn = ntohl(sdh->cum_tsn_ack); 2640 2641 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2642 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2643 asoc->ctsn_ack_point); 2644 2645 return SCTP_DISPOSITION_DISCARD; 2646 } 2647 2648 /* If Cumulative TSN Ack beyond the max tsn currently 2649 * send, terminating the association and respond to the 2650 * sender with an ABORT. 2651 */ 2652 if (!TSN_lt(ctsn, asoc->next_tsn)) 2653 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2654 2655 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2656 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2657 * inform the application that it should cease sending data. 2658 */ 2659 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2660 if (!ev) { 2661 disposition = SCTP_DISPOSITION_NOMEM; 2662 goto out; 2663 } 2664 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2665 2666 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2667 * - enter the SHUTDOWN-RECEIVED state, 2668 * - stop accepting new data from its SCTP user 2669 * 2670 * [This is implicit in the new state.] 2671 */ 2672 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2673 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2674 disposition = SCTP_DISPOSITION_CONSUME; 2675 2676 if (sctp_outq_is_empty(&asoc->outqueue)) { 2677 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2678 arg, commands); 2679 } 2680 2681 if (SCTP_DISPOSITION_NOMEM == disposition) 2682 goto out; 2683 2684 /* - verify, by checking the Cumulative TSN Ack field of the 2685 * chunk, that all its outstanding DATA chunks have been 2686 * received by the SHUTDOWN sender. 2687 */ 2688 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2689 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2690 2691 out: 2692 return disposition; 2693 } 2694 2695 /* 2696 * sctp_sf_do_9_2_shut_ctsn 2697 * 2698 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2699 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2700 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2701 * MUST be processed. 2702 */ 2703 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2704 const struct sctp_endpoint *ep, 2705 const struct sctp_association *asoc, 2706 const sctp_subtype_t type, 2707 void *arg, 2708 sctp_cmd_seq_t *commands) 2709 { 2710 struct sctp_chunk *chunk = arg; 2711 sctp_shutdownhdr_t *sdh; 2712 __u32 ctsn; 2713 2714 if (!sctp_vtag_verify(chunk, asoc)) 2715 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2716 2717 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2718 if (!sctp_chunk_length_valid(chunk, 2719 sizeof(struct sctp_shutdown_chunk_t))) 2720 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2721 commands); 2722 2723 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2724 ctsn = ntohl(sdh->cum_tsn_ack); 2725 2726 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2727 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2728 asoc->ctsn_ack_point); 2729 2730 return SCTP_DISPOSITION_DISCARD; 2731 } 2732 2733 /* If Cumulative TSN Ack beyond the max tsn currently 2734 * send, terminating the association and respond to the 2735 * sender with an ABORT. 2736 */ 2737 if (!TSN_lt(ctsn, asoc->next_tsn)) 2738 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2739 2740 /* verify, by checking the Cumulative TSN Ack field of the 2741 * chunk, that all its outstanding DATA chunks have been 2742 * received by the SHUTDOWN sender. 2743 */ 2744 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2745 SCTP_BE32(sdh->cum_tsn_ack)); 2746 2747 return SCTP_DISPOSITION_CONSUME; 2748 } 2749 2750 /* RFC 2960 9.2 2751 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2752 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2753 * transport addresses (either in the IP addresses or in the INIT chunk) 2754 * that belong to this association, it should discard the INIT chunk and 2755 * retransmit the SHUTDOWN ACK chunk. 2756 */ 2757 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2758 const struct sctp_endpoint *ep, 2759 const struct sctp_association *asoc, 2760 const sctp_subtype_t type, 2761 void *arg, 2762 sctp_cmd_seq_t *commands) 2763 { 2764 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2765 struct sctp_chunk *reply; 2766 2767 /* Make sure that the chunk has a valid length */ 2768 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2769 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2770 commands); 2771 2772 /* Since we are not going to really process this INIT, there 2773 * is no point in verifying chunk boundries. Just generate 2774 * the SHUTDOWN ACK. 2775 */ 2776 reply = sctp_make_shutdown_ack(asoc, chunk); 2777 if (NULL == reply) 2778 goto nomem; 2779 2780 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2781 * the T2-SHUTDOWN timer. 2782 */ 2783 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2784 2785 /* and restart the T2-shutdown timer. */ 2786 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2787 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2788 2789 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2790 2791 return SCTP_DISPOSITION_CONSUME; 2792 nomem: 2793 return SCTP_DISPOSITION_NOMEM; 2794 } 2795 2796 /* 2797 * sctp_sf_do_ecn_cwr 2798 * 2799 * Section: Appendix A: Explicit Congestion Notification 2800 * 2801 * CWR: 2802 * 2803 * RFC 2481 details a specific bit for a sender to send in the header of 2804 * its next outbound TCP segment to indicate to its peer that it has 2805 * reduced its congestion window. This is termed the CWR bit. For 2806 * SCTP the same indication is made by including the CWR chunk. 2807 * This chunk contains one data element, i.e. the TSN number that 2808 * was sent in the ECNE chunk. This element represents the lowest 2809 * TSN number in the datagram that was originally marked with the 2810 * CE bit. 2811 * 2812 * Verification Tag: 8.5 Verification Tag [Normal verification] 2813 * Inputs 2814 * (endpoint, asoc, chunk) 2815 * 2816 * Outputs 2817 * (asoc, reply_msg, msg_up, timers, counters) 2818 * 2819 * The return value is the disposition of the chunk. 2820 */ 2821 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2822 const struct sctp_endpoint *ep, 2823 const struct sctp_association *asoc, 2824 const sctp_subtype_t type, 2825 void *arg, 2826 sctp_cmd_seq_t *commands) 2827 { 2828 sctp_cwrhdr_t *cwr; 2829 struct sctp_chunk *chunk = arg; 2830 u32 lowest_tsn; 2831 2832 if (!sctp_vtag_verify(chunk, asoc)) 2833 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2834 2835 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2836 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2837 commands); 2838 2839 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2840 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2841 2842 lowest_tsn = ntohl(cwr->lowest_tsn); 2843 2844 /* Does this CWR ack the last sent congestion notification? */ 2845 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2846 /* Stop sending ECNE. */ 2847 sctp_add_cmd_sf(commands, 2848 SCTP_CMD_ECN_CWR, 2849 SCTP_U32(lowest_tsn)); 2850 } 2851 return SCTP_DISPOSITION_CONSUME; 2852 } 2853 2854 /* 2855 * sctp_sf_do_ecne 2856 * 2857 * Section: Appendix A: Explicit Congestion Notification 2858 * 2859 * ECN-Echo 2860 * 2861 * RFC 2481 details a specific bit for a receiver to send back in its 2862 * TCP acknowledgements to notify the sender of the Congestion 2863 * Experienced (CE) bit having arrived from the network. For SCTP this 2864 * same indication is made by including the ECNE chunk. This chunk 2865 * contains one data element, i.e. the lowest TSN associated with the IP 2866 * datagram marked with the CE bit..... 2867 * 2868 * Verification Tag: 8.5 Verification Tag [Normal verification] 2869 * Inputs 2870 * (endpoint, asoc, chunk) 2871 * 2872 * Outputs 2873 * (asoc, reply_msg, msg_up, timers, counters) 2874 * 2875 * The return value is the disposition of the chunk. 2876 */ 2877 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2878 const struct sctp_endpoint *ep, 2879 const struct sctp_association *asoc, 2880 const sctp_subtype_t type, 2881 void *arg, 2882 sctp_cmd_seq_t *commands) 2883 { 2884 sctp_ecnehdr_t *ecne; 2885 struct sctp_chunk *chunk = arg; 2886 2887 if (!sctp_vtag_verify(chunk, asoc)) 2888 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2889 2890 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2891 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2892 commands); 2893 2894 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2895 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2896 2897 /* If this is a newer ECNE than the last CWR packet we sent out */ 2898 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2899 SCTP_U32(ntohl(ecne->lowest_tsn))); 2900 2901 return SCTP_DISPOSITION_CONSUME; 2902 } 2903 2904 /* 2905 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2906 * 2907 * The SCTP endpoint MUST always acknowledge the reception of each valid 2908 * DATA chunk. 2909 * 2910 * The guidelines on delayed acknowledgement algorithm specified in 2911 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2912 * acknowledgement SHOULD be generated for at least every second packet 2913 * (not every second DATA chunk) received, and SHOULD be generated within 2914 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2915 * situations it may be beneficial for an SCTP transmitter to be more 2916 * conservative than the algorithms detailed in this document allow. 2917 * However, an SCTP transmitter MUST NOT be more aggressive than the 2918 * following algorithms allow. 2919 * 2920 * A SCTP receiver MUST NOT generate more than one SACK for every 2921 * incoming packet, other than to update the offered window as the 2922 * receiving application consumes new data. 2923 * 2924 * Verification Tag: 8.5 Verification Tag [Normal verification] 2925 * 2926 * Inputs 2927 * (endpoint, asoc, chunk) 2928 * 2929 * Outputs 2930 * (asoc, reply_msg, msg_up, timers, counters) 2931 * 2932 * The return value is the disposition of the chunk. 2933 */ 2934 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2935 const struct sctp_endpoint *ep, 2936 const struct sctp_association *asoc, 2937 const sctp_subtype_t type, 2938 void *arg, 2939 sctp_cmd_seq_t *commands) 2940 { 2941 struct sctp_chunk *chunk = arg; 2942 sctp_arg_t force = SCTP_NOFORCE(); 2943 int error; 2944 2945 if (!sctp_vtag_verify(chunk, asoc)) { 2946 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2947 SCTP_NULL()); 2948 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2949 } 2950 2951 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2952 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2953 commands); 2954 2955 error = sctp_eat_data(asoc, chunk, commands); 2956 switch (error) { 2957 case SCTP_IERROR_NO_ERROR: 2958 break; 2959 case SCTP_IERROR_HIGH_TSN: 2960 case SCTP_IERROR_BAD_STREAM: 2961 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2962 goto discard_noforce; 2963 case SCTP_IERROR_DUP_TSN: 2964 case SCTP_IERROR_IGNORE_TSN: 2965 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2966 goto discard_force; 2967 case SCTP_IERROR_NO_DATA: 2968 goto consume; 2969 case SCTP_IERROR_PROTO_VIOLATION: 2970 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 2971 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2972 default: 2973 BUG(); 2974 } 2975 2976 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2977 force = SCTP_FORCE(); 2978 2979 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 2980 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2981 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2982 } 2983 2984 /* If this is the last chunk in a packet, we need to count it 2985 * toward sack generation. Note that we need to SACK every 2986 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2987 * THEM. We elect to NOT generate SACK's if the chunk fails 2988 * the verification tag test. 2989 * 2990 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2991 * 2992 * The SCTP endpoint MUST always acknowledge the reception of 2993 * each valid DATA chunk. 2994 * 2995 * The guidelines on delayed acknowledgement algorithm 2996 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2997 * Specifically, an acknowledgement SHOULD be generated for at 2998 * least every second packet (not every second DATA chunk) 2999 * received, and SHOULD be generated within 200 ms of the 3000 * arrival of any unacknowledged DATA chunk. In some 3001 * situations it may be beneficial for an SCTP transmitter to 3002 * be more conservative than the algorithms detailed in this 3003 * document allow. However, an SCTP transmitter MUST NOT be 3004 * more aggressive than the following algorithms allow. 3005 */ 3006 if (chunk->end_of_packet) 3007 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3008 3009 return SCTP_DISPOSITION_CONSUME; 3010 3011 discard_force: 3012 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3013 * 3014 * When a packet arrives with duplicate DATA chunk(s) and with 3015 * no new DATA chunk(s), the endpoint MUST immediately send a 3016 * SACK with no delay. If a packet arrives with duplicate 3017 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3018 * MAY immediately send a SACK. Normally receipt of duplicate 3019 * DATA chunks will occur when the original SACK chunk was lost 3020 * and the peer's RTO has expired. The duplicate TSN number(s) 3021 * SHOULD be reported in the SACK as duplicate. 3022 */ 3023 /* In our case, we split the MAY SACK advice up whether or not 3024 * the last chunk is a duplicate.' 3025 */ 3026 if (chunk->end_of_packet) 3027 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3028 return SCTP_DISPOSITION_DISCARD; 3029 3030 discard_noforce: 3031 if (chunk->end_of_packet) 3032 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3033 3034 return SCTP_DISPOSITION_DISCARD; 3035 consume: 3036 return SCTP_DISPOSITION_CONSUME; 3037 3038 } 3039 3040 /* 3041 * sctp_sf_eat_data_fast_4_4 3042 * 3043 * Section: 4 (4) 3044 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3045 * DATA chunks without delay. 3046 * 3047 * Verification Tag: 8.5 Verification Tag [Normal verification] 3048 * Inputs 3049 * (endpoint, asoc, chunk) 3050 * 3051 * Outputs 3052 * (asoc, reply_msg, msg_up, timers, counters) 3053 * 3054 * The return value is the disposition of the chunk. 3055 */ 3056 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3057 const struct sctp_endpoint *ep, 3058 const struct sctp_association *asoc, 3059 const sctp_subtype_t type, 3060 void *arg, 3061 sctp_cmd_seq_t *commands) 3062 { 3063 struct sctp_chunk *chunk = arg; 3064 int error; 3065 3066 if (!sctp_vtag_verify(chunk, asoc)) { 3067 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3068 SCTP_NULL()); 3069 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3070 } 3071 3072 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3073 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3074 commands); 3075 3076 error = sctp_eat_data(asoc, chunk, commands); 3077 switch (error) { 3078 case SCTP_IERROR_NO_ERROR: 3079 case SCTP_IERROR_HIGH_TSN: 3080 case SCTP_IERROR_DUP_TSN: 3081 case SCTP_IERROR_IGNORE_TSN: 3082 case SCTP_IERROR_BAD_STREAM: 3083 break; 3084 case SCTP_IERROR_NO_DATA: 3085 goto consume; 3086 case SCTP_IERROR_PROTO_VIOLATION: 3087 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3088 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3089 default: 3090 BUG(); 3091 } 3092 3093 /* Go a head and force a SACK, since we are shutting down. */ 3094 3095 /* Implementor's Guide. 3096 * 3097 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3098 * respond to each received packet containing one or more DATA chunk(s) 3099 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3100 */ 3101 if (chunk->end_of_packet) { 3102 /* We must delay the chunk creation since the cumulative 3103 * TSN has not been updated yet. 3104 */ 3105 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3106 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3107 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3108 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3109 } 3110 3111 consume: 3112 return SCTP_DISPOSITION_CONSUME; 3113 } 3114 3115 /* 3116 * Section: 6.2 Processing a Received SACK 3117 * D) Any time a SACK arrives, the endpoint performs the following: 3118 * 3119 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3120 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3121 * increasing, a SACK whose Cumulative TSN Ack is less than the 3122 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3123 * 3124 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3125 * of bytes still outstanding after processing the Cumulative TSN Ack 3126 * and the Gap Ack Blocks. 3127 * 3128 * iii) If the SACK is missing a TSN that was previously 3129 * acknowledged via a Gap Ack Block (e.g., the data receiver 3130 * reneged on the data), then mark the corresponding DATA chunk 3131 * as available for retransmit: Mark it as missing for fast 3132 * retransmit as described in Section 7.2.4 and if no retransmit 3133 * timer is running for the destination address to which the DATA 3134 * chunk was originally transmitted, then T3-rtx is started for 3135 * that destination address. 3136 * 3137 * Verification Tag: 8.5 Verification Tag [Normal verification] 3138 * 3139 * Inputs 3140 * (endpoint, asoc, chunk) 3141 * 3142 * Outputs 3143 * (asoc, reply_msg, msg_up, timers, counters) 3144 * 3145 * The return value is the disposition of the chunk. 3146 */ 3147 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3148 const struct sctp_endpoint *ep, 3149 const struct sctp_association *asoc, 3150 const sctp_subtype_t type, 3151 void *arg, 3152 sctp_cmd_seq_t *commands) 3153 { 3154 struct sctp_chunk *chunk = arg; 3155 sctp_sackhdr_t *sackh; 3156 __u32 ctsn; 3157 3158 if (!sctp_vtag_verify(chunk, asoc)) 3159 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3160 3161 /* Make sure that the SACK chunk has a valid length. */ 3162 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3163 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3164 commands); 3165 3166 /* Pull the SACK chunk from the data buffer */ 3167 sackh = sctp_sm_pull_sack(chunk); 3168 /* Was this a bogus SACK? */ 3169 if (!sackh) 3170 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3171 chunk->subh.sack_hdr = sackh; 3172 ctsn = ntohl(sackh->cum_tsn_ack); 3173 3174 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3175 * Ack Point, then drop the SACK. Since Cumulative TSN 3176 * Ack is monotonically increasing, a SACK whose 3177 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3178 * Point indicates an out-of-order SACK. 3179 */ 3180 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3181 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3182 asoc->ctsn_ack_point); 3183 3184 return SCTP_DISPOSITION_DISCARD; 3185 } 3186 3187 /* If Cumulative TSN Ack beyond the max tsn currently 3188 * send, terminating the association and respond to the 3189 * sender with an ABORT. 3190 */ 3191 if (!TSN_lt(ctsn, asoc->next_tsn)) 3192 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3193 3194 /* Return this SACK for further processing. */ 3195 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3196 3197 /* Note: We do the rest of the work on the PROCESS_SACK 3198 * sideeffect. 3199 */ 3200 return SCTP_DISPOSITION_CONSUME; 3201 } 3202 3203 /* 3204 * Generate an ABORT in response to a packet. 3205 * 3206 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3207 * 3208 * 8) The receiver should respond to the sender of the OOTB packet with 3209 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3210 * MUST fill in the Verification Tag field of the outbound packet 3211 * with the value found in the Verification Tag field of the OOTB 3212 * packet and set the T-bit in the Chunk Flags to indicate that the 3213 * Verification Tag is reflected. After sending this ABORT, the 3214 * receiver of the OOTB packet shall discard the OOTB packet and take 3215 * no further action. 3216 * 3217 * Verification Tag: 3218 * 3219 * The return value is the disposition of the chunk. 3220 */ 3221 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3222 const struct sctp_endpoint *ep, 3223 const struct sctp_association *asoc, 3224 const sctp_subtype_t type, 3225 void *arg, 3226 sctp_cmd_seq_t *commands) 3227 { 3228 struct sctp_packet *packet = NULL; 3229 struct sctp_chunk *chunk = arg; 3230 struct sctp_chunk *abort; 3231 3232 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3233 3234 if (packet) { 3235 /* Make an ABORT. The T bit will be set if the asoc 3236 * is NULL. 3237 */ 3238 abort = sctp_make_abort(asoc, chunk, 0); 3239 if (!abort) { 3240 sctp_ootb_pkt_free(packet); 3241 return SCTP_DISPOSITION_NOMEM; 3242 } 3243 3244 /* Reflect vtag if T-Bit is set */ 3245 if (sctp_test_T_bit(abort)) 3246 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3247 3248 /* Set the skb to the belonging sock for accounting. */ 3249 abort->skb->sk = ep->base.sk; 3250 3251 sctp_packet_append_chunk(packet, abort); 3252 3253 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3254 SCTP_PACKET(packet)); 3255 3256 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3257 3258 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3259 return SCTP_DISPOSITION_CONSUME; 3260 } 3261 3262 return SCTP_DISPOSITION_NOMEM; 3263 } 3264 3265 /* 3266 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3267 * event as ULP notification for each cause included in the chunk. 3268 * 3269 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3270 * 3271 * The return value is the disposition of the chunk. 3272 */ 3273 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3274 const struct sctp_endpoint *ep, 3275 const struct sctp_association *asoc, 3276 const sctp_subtype_t type, 3277 void *arg, 3278 sctp_cmd_seq_t *commands) 3279 { 3280 struct sctp_chunk *chunk = arg; 3281 sctp_errhdr_t *err; 3282 3283 if (!sctp_vtag_verify(chunk, asoc)) 3284 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3285 3286 /* Make sure that the ERROR chunk has a valid length. */ 3287 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3288 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3289 commands); 3290 sctp_walk_errors(err, chunk->chunk_hdr); 3291 if ((void *)err != (void *)chunk->chunk_end) 3292 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3293 (void *)err, commands); 3294 3295 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3296 SCTP_CHUNK(chunk)); 3297 3298 return SCTP_DISPOSITION_CONSUME; 3299 } 3300 3301 /* 3302 * Process an inbound SHUTDOWN ACK. 3303 * 3304 * From Section 9.2: 3305 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3306 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3307 * peer, and remove all record of the association. 3308 * 3309 * The return value is the disposition. 3310 */ 3311 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3312 const struct sctp_endpoint *ep, 3313 const struct sctp_association *asoc, 3314 const sctp_subtype_t type, 3315 void *arg, 3316 sctp_cmd_seq_t *commands) 3317 { 3318 struct sctp_chunk *chunk = arg; 3319 struct sctp_chunk *reply; 3320 struct sctp_ulpevent *ev; 3321 3322 if (!sctp_vtag_verify(chunk, asoc)) 3323 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3324 3325 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3326 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3327 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3328 commands); 3329 /* 10.2 H) SHUTDOWN COMPLETE notification 3330 * 3331 * When SCTP completes the shutdown procedures (section 9.2) this 3332 * notification is passed to the upper layer. 3333 */ 3334 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3335 0, 0, 0, NULL, GFP_ATOMIC); 3336 if (!ev) 3337 goto nomem; 3338 3339 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3340 reply = sctp_make_shutdown_complete(asoc, chunk); 3341 if (!reply) 3342 goto nomem_chunk; 3343 3344 /* Do all the commands now (after allocation), so that we 3345 * have consistent state if memory allocation failes 3346 */ 3347 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3348 3349 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3350 * stop the T2-shutdown timer, 3351 */ 3352 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3353 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3354 3355 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3356 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3357 3358 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3359 SCTP_STATE(SCTP_STATE_CLOSED)); 3360 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3361 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3362 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3363 3364 /* ...and remove all record of the association. */ 3365 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3366 return SCTP_DISPOSITION_DELETE_TCB; 3367 3368 nomem_chunk: 3369 sctp_ulpevent_free(ev); 3370 nomem: 3371 return SCTP_DISPOSITION_NOMEM; 3372 } 3373 3374 /* 3375 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3376 * 3377 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3378 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3379 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3380 * packet must fill in the Verification Tag field of the outbound 3381 * packet with the Verification Tag received in the SHUTDOWN ACK and 3382 * set the T-bit in the Chunk Flags to indicate that the Verification 3383 * Tag is reflected. 3384 * 3385 * 8) The receiver should respond to the sender of the OOTB packet with 3386 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3387 * MUST fill in the Verification Tag field of the outbound packet 3388 * with the value found in the Verification Tag field of the OOTB 3389 * packet and set the T-bit in the Chunk Flags to indicate that the 3390 * Verification Tag is reflected. After sending this ABORT, the 3391 * receiver of the OOTB packet shall discard the OOTB packet and take 3392 * no further action. 3393 */ 3394 sctp_disposition_t sctp_sf_ootb(struct net *net, 3395 const struct sctp_endpoint *ep, 3396 const struct sctp_association *asoc, 3397 const sctp_subtype_t type, 3398 void *arg, 3399 sctp_cmd_seq_t *commands) 3400 { 3401 struct sctp_chunk *chunk = arg; 3402 struct sk_buff *skb = chunk->skb; 3403 sctp_chunkhdr_t *ch; 3404 sctp_errhdr_t *err; 3405 __u8 *ch_end; 3406 int ootb_shut_ack = 0; 3407 int ootb_cookie_ack = 0; 3408 3409 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3410 3411 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3412 do { 3413 /* Report violation if the chunk is less then minimal */ 3414 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3415 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3416 commands); 3417 3418 /* Now that we know we at least have a chunk header, 3419 * do things that are type appropriate. 3420 */ 3421 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3422 ootb_shut_ack = 1; 3423 3424 /* RFC 2960, Section 3.3.7 3425 * Moreover, under any circumstances, an endpoint that 3426 * receives an ABORT MUST NOT respond to that ABORT by 3427 * sending an ABORT of its own. 3428 */ 3429 if (SCTP_CID_ABORT == ch->type) 3430 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3431 3432 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3433 * or a COOKIE ACK the SCTP Packet should be silently 3434 * discarded. 3435 */ 3436 3437 if (SCTP_CID_COOKIE_ACK == ch->type) 3438 ootb_cookie_ack = 1; 3439 3440 if (SCTP_CID_ERROR == ch->type) { 3441 sctp_walk_errors(err, ch) { 3442 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3443 ootb_cookie_ack = 1; 3444 break; 3445 } 3446 } 3447 } 3448 3449 /* Report violation if chunk len overflows */ 3450 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3451 if (ch_end > skb_tail_pointer(skb)) 3452 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3453 commands); 3454 3455 ch = (sctp_chunkhdr_t *) ch_end; 3456 } while (ch_end < skb_tail_pointer(skb)); 3457 3458 if (ootb_shut_ack) 3459 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3460 else if (ootb_cookie_ack) 3461 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3462 else 3463 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3464 } 3465 3466 /* 3467 * Handle an "Out of the blue" SHUTDOWN ACK. 3468 * 3469 * Section: 8.4 5, sctpimpguide 2.41. 3470 * 3471 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3472 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3473 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3474 * packet must fill in the Verification Tag field of the outbound 3475 * packet with the Verification Tag received in the SHUTDOWN ACK and 3476 * set the T-bit in the Chunk Flags to indicate that the Verification 3477 * Tag is reflected. 3478 * 3479 * Inputs 3480 * (endpoint, asoc, type, arg, commands) 3481 * 3482 * Outputs 3483 * (sctp_disposition_t) 3484 * 3485 * The return value is the disposition of the chunk. 3486 */ 3487 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3488 const struct sctp_endpoint *ep, 3489 const struct sctp_association *asoc, 3490 const sctp_subtype_t type, 3491 void *arg, 3492 sctp_cmd_seq_t *commands) 3493 { 3494 struct sctp_packet *packet = NULL; 3495 struct sctp_chunk *chunk = arg; 3496 struct sctp_chunk *shut; 3497 3498 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3499 3500 if (packet) { 3501 /* Make an SHUTDOWN_COMPLETE. 3502 * The T bit will be set if the asoc is NULL. 3503 */ 3504 shut = sctp_make_shutdown_complete(asoc, chunk); 3505 if (!shut) { 3506 sctp_ootb_pkt_free(packet); 3507 return SCTP_DISPOSITION_NOMEM; 3508 } 3509 3510 /* Reflect vtag if T-Bit is set */ 3511 if (sctp_test_T_bit(shut)) 3512 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3513 3514 /* Set the skb to the belonging sock for accounting. */ 3515 shut->skb->sk = ep->base.sk; 3516 3517 sctp_packet_append_chunk(packet, shut); 3518 3519 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3520 SCTP_PACKET(packet)); 3521 3522 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3523 3524 /* If the chunk length is invalid, we don't want to process 3525 * the reset of the packet. 3526 */ 3527 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3528 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3529 3530 /* We need to discard the rest of the packet to prevent 3531 * potential bomming attacks from additional bundled chunks. 3532 * This is documented in SCTP Threats ID. 3533 */ 3534 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3535 } 3536 3537 return SCTP_DISPOSITION_NOMEM; 3538 } 3539 3540 /* 3541 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3542 * 3543 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3544 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3545 * procedures in section 8.4 SHOULD be followed, in other words it 3546 * should be treated as an Out Of The Blue packet. 3547 * [This means that we do NOT check the Verification Tag on these 3548 * chunks. --piggy ] 3549 * 3550 */ 3551 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3552 const struct sctp_endpoint *ep, 3553 const struct sctp_association *asoc, 3554 const sctp_subtype_t type, 3555 void *arg, 3556 sctp_cmd_seq_t *commands) 3557 { 3558 struct sctp_chunk *chunk = arg; 3559 3560 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3561 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3562 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3563 commands); 3564 3565 /* Although we do have an association in this case, it corresponds 3566 * to a restarted association. So the packet is treated as an OOTB 3567 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3568 * called with a NULL association. 3569 */ 3570 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3571 3572 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3573 } 3574 3575 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3576 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3577 const struct sctp_endpoint *ep, 3578 const struct sctp_association *asoc, 3579 const sctp_subtype_t type, void *arg, 3580 sctp_cmd_seq_t *commands) 3581 { 3582 struct sctp_chunk *chunk = arg; 3583 struct sctp_chunk *asconf_ack = NULL; 3584 struct sctp_paramhdr *err_param = NULL; 3585 sctp_addiphdr_t *hdr; 3586 union sctp_addr_param *addr_param; 3587 __u32 serial; 3588 int length; 3589 3590 if (!sctp_vtag_verify(chunk, asoc)) { 3591 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3592 SCTP_NULL()); 3593 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3594 } 3595 3596 /* ADD-IP: Section 4.1.1 3597 * This chunk MUST be sent in an authenticated way by using 3598 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3599 * is received unauthenticated it MUST be silently discarded as 3600 * described in [I-D.ietf-tsvwg-sctp-auth]. 3601 */ 3602 if (!net->sctp.addip_noauth && !chunk->auth) 3603 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3604 3605 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3606 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3607 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3608 commands); 3609 3610 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3611 serial = ntohl(hdr->serial); 3612 3613 addr_param = (union sctp_addr_param *)hdr->params; 3614 length = ntohs(addr_param->p.length); 3615 if (length < sizeof(sctp_paramhdr_t)) 3616 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3617 (void *)addr_param, commands); 3618 3619 /* Verify the ASCONF chunk before processing it. */ 3620 if (!sctp_verify_asconf(asoc, 3621 (sctp_paramhdr_t *)((void *)addr_param + length), 3622 (void *)chunk->chunk_end, 3623 &err_param)) 3624 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3625 (void *)err_param, commands); 3626 3627 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3628 * the endpoint stored in a new association variable 3629 * 'Peer-Serial-Number'. 3630 */ 3631 if (serial == asoc->peer.addip_serial + 1) { 3632 /* If this is the first instance of ASCONF in the packet, 3633 * we can clean our old ASCONF-ACKs. 3634 */ 3635 if (!chunk->has_asconf) 3636 sctp_assoc_clean_asconf_ack_cache(asoc); 3637 3638 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3639 * expected, process the ASCONF as described below and after 3640 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3641 * the response packet and cache a copy of it (in the event it 3642 * later needs to be retransmitted). 3643 * 3644 * Essentially, do V1-V5. 3645 */ 3646 asconf_ack = sctp_process_asconf((struct sctp_association *) 3647 asoc, chunk); 3648 if (!asconf_ack) 3649 return SCTP_DISPOSITION_NOMEM; 3650 } else if (serial < asoc->peer.addip_serial + 1) { 3651 /* ADDIP 5.2 E2) 3652 * If the value found in the Sequence Number is less than the 3653 * ('Peer- Sequence-Number' + 1), simply skip to the next 3654 * ASCONF, and include in the outbound response packet 3655 * any previously cached ASCONF-ACK response that was 3656 * sent and saved that matches the Sequence Number of the 3657 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3658 * Chunk exists. This will occur when an older ASCONF 3659 * arrives out of order. In such a case, the receiver 3660 * should skip the ASCONF Chunk and not include ASCONF-ACK 3661 * Chunk for that chunk. 3662 */ 3663 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3664 if (!asconf_ack) 3665 return SCTP_DISPOSITION_DISCARD; 3666 3667 /* Reset the transport so that we select the correct one 3668 * this time around. This is to make sure that we don't 3669 * accidentally use a stale transport that's been removed. 3670 */ 3671 asconf_ack->transport = NULL; 3672 } else { 3673 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3674 * it must be either a stale packet or from an attacker. 3675 */ 3676 return SCTP_DISPOSITION_DISCARD; 3677 } 3678 3679 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3680 * containing the ASCONF-ACK Chunks MUST be the source address of 3681 * the SCTP packet that held the ASCONF Chunks. 3682 * 3683 * To do this properly, we'll set the destination address of the chunk 3684 * and at the transmit time, will try look up the transport to use. 3685 * Since ASCONFs may be bundled, the correct transport may not be 3686 * created until we process the entire packet, thus this workaround. 3687 */ 3688 asconf_ack->dest = chunk->source; 3689 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3690 if (asoc->new_transport) { 3691 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3692 ((struct sctp_association *)asoc)->new_transport = NULL; 3693 } 3694 3695 return SCTP_DISPOSITION_CONSUME; 3696 } 3697 3698 /* 3699 * ADDIP Section 4.3 General rules for address manipulation 3700 * When building TLV parameters for the ASCONF Chunk that will add or 3701 * delete IP addresses the D0 to D13 rules should be applied: 3702 */ 3703 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3704 const struct sctp_endpoint *ep, 3705 const struct sctp_association *asoc, 3706 const sctp_subtype_t type, void *arg, 3707 sctp_cmd_seq_t *commands) 3708 { 3709 struct sctp_chunk *asconf_ack = arg; 3710 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3711 struct sctp_chunk *abort; 3712 struct sctp_paramhdr *err_param = NULL; 3713 sctp_addiphdr_t *addip_hdr; 3714 __u32 sent_serial, rcvd_serial; 3715 3716 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3717 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3718 SCTP_NULL()); 3719 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3720 } 3721 3722 /* ADD-IP, Section 4.1.2: 3723 * This chunk MUST be sent in an authenticated way by using 3724 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3725 * is received unauthenticated it MUST be silently discarded as 3726 * described in [I-D.ietf-tsvwg-sctp-auth]. 3727 */ 3728 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3729 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3730 3731 /* Make sure that the ADDIP chunk has a valid length. */ 3732 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3733 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3734 commands); 3735 3736 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3737 rcvd_serial = ntohl(addip_hdr->serial); 3738 3739 /* Verify the ASCONF-ACK chunk before processing it. */ 3740 if (!sctp_verify_asconf(asoc, 3741 (sctp_paramhdr_t *)addip_hdr->params, 3742 (void *)asconf_ack->chunk_end, 3743 &err_param)) 3744 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3745 (void *)err_param, commands); 3746 3747 if (last_asconf) { 3748 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3749 sent_serial = ntohl(addip_hdr->serial); 3750 } else { 3751 sent_serial = asoc->addip_serial - 1; 3752 } 3753 3754 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3755 * equal to the next serial number to be used but no ASCONF chunk is 3756 * outstanding the endpoint MUST ABORT the association. Note that a 3757 * sequence number is greater than if it is no more than 2^^31-1 3758 * larger than the current sequence number (using serial arithmetic). 3759 */ 3760 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3761 !(asoc->addip_last_asconf)) { 3762 abort = sctp_make_abort(asoc, asconf_ack, 3763 sizeof(sctp_errhdr_t)); 3764 if (abort) { 3765 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3766 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3767 SCTP_CHUNK(abort)); 3768 } 3769 /* We are going to ABORT, so we might as well stop 3770 * processing the rest of the chunks in the packet. 3771 */ 3772 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3773 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3774 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3775 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3776 SCTP_ERROR(ECONNABORTED)); 3777 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3778 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3779 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3780 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3781 return SCTP_DISPOSITION_ABORT; 3782 } 3783 3784 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3785 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3786 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3787 3788 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3789 asconf_ack)) { 3790 /* Successfully processed ASCONF_ACK. We can 3791 * release the next asconf if we have one. 3792 */ 3793 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3794 SCTP_NULL()); 3795 return SCTP_DISPOSITION_CONSUME; 3796 } 3797 3798 abort = sctp_make_abort(asoc, asconf_ack, 3799 sizeof(sctp_errhdr_t)); 3800 if (abort) { 3801 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3802 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3803 SCTP_CHUNK(abort)); 3804 } 3805 /* We are going to ABORT, so we might as well stop 3806 * processing the rest of the chunks in the packet. 3807 */ 3808 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3809 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3810 SCTP_ERROR(ECONNABORTED)); 3811 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3812 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3813 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3814 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3815 return SCTP_DISPOSITION_ABORT; 3816 } 3817 3818 return SCTP_DISPOSITION_DISCARD; 3819 } 3820 3821 /* 3822 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3823 * 3824 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3825 * its cumulative TSN point to the value carried in the FORWARD TSN 3826 * chunk, and then MUST further advance its cumulative TSN point locally 3827 * if possible. 3828 * After the above processing, the data receiver MUST stop reporting any 3829 * missing TSNs earlier than or equal to the new cumulative TSN point. 3830 * 3831 * Verification Tag: 8.5 Verification Tag [Normal verification] 3832 * 3833 * The return value is the disposition of the chunk. 3834 */ 3835 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3836 const struct sctp_endpoint *ep, 3837 const struct sctp_association *asoc, 3838 const sctp_subtype_t type, 3839 void *arg, 3840 sctp_cmd_seq_t *commands) 3841 { 3842 struct sctp_chunk *chunk = arg; 3843 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3844 struct sctp_fwdtsn_skip *skip; 3845 __u16 len; 3846 __u32 tsn; 3847 3848 if (!sctp_vtag_verify(chunk, asoc)) { 3849 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3850 SCTP_NULL()); 3851 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3852 } 3853 3854 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3855 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3856 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3857 commands); 3858 3859 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3860 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3861 len = ntohs(chunk->chunk_hdr->length); 3862 len -= sizeof(struct sctp_chunkhdr); 3863 skb_pull(chunk->skb, len); 3864 3865 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3866 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3867 3868 /* The TSN is too high--silently discard the chunk and count on it 3869 * getting retransmitted later. 3870 */ 3871 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3872 goto discard_noforce; 3873 3874 /* Silently discard the chunk if stream-id is not valid */ 3875 sctp_walk_fwdtsn(skip, chunk) { 3876 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3877 goto discard_noforce; 3878 } 3879 3880 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3881 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3882 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3883 SCTP_CHUNK(chunk)); 3884 3885 /* Count this as receiving DATA. */ 3886 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3887 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3888 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3889 } 3890 3891 /* FIXME: For now send a SACK, but DATA processing may 3892 * send another. 3893 */ 3894 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3895 3896 return SCTP_DISPOSITION_CONSUME; 3897 3898 discard_noforce: 3899 return SCTP_DISPOSITION_DISCARD; 3900 } 3901 3902 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3903 struct net *net, 3904 const struct sctp_endpoint *ep, 3905 const struct sctp_association *asoc, 3906 const sctp_subtype_t type, 3907 void *arg, 3908 sctp_cmd_seq_t *commands) 3909 { 3910 struct sctp_chunk *chunk = arg; 3911 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3912 struct sctp_fwdtsn_skip *skip; 3913 __u16 len; 3914 __u32 tsn; 3915 3916 if (!sctp_vtag_verify(chunk, asoc)) { 3917 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3918 SCTP_NULL()); 3919 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3920 } 3921 3922 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3923 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3924 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3925 commands); 3926 3927 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3928 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3929 len = ntohs(chunk->chunk_hdr->length); 3930 len -= sizeof(struct sctp_chunkhdr); 3931 skb_pull(chunk->skb, len); 3932 3933 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3934 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3935 3936 /* The TSN is too high--silently discard the chunk and count on it 3937 * getting retransmitted later. 3938 */ 3939 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3940 goto gen_shutdown; 3941 3942 /* Silently discard the chunk if stream-id is not valid */ 3943 sctp_walk_fwdtsn(skip, chunk) { 3944 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3945 goto gen_shutdown; 3946 } 3947 3948 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3949 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3950 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3951 SCTP_CHUNK(chunk)); 3952 3953 /* Go a head and force a SACK, since we are shutting down. */ 3954 gen_shutdown: 3955 /* Implementor's Guide. 3956 * 3957 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3958 * respond to each received packet containing one or more DATA chunk(s) 3959 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3960 */ 3961 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3962 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3963 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3964 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3965 3966 return SCTP_DISPOSITION_CONSUME; 3967 } 3968 3969 /* 3970 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3971 * 3972 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3973 * Identifier field. If this algorithm was not specified by the 3974 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3975 * during association setup, the AUTH chunk and all chunks after it MUST 3976 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3977 * defined in Section 4.1. 3978 * 3979 * If an endpoint with no shared key receives a Shared Key Identifier 3980 * other than 0, it MUST silently discard all authenticated chunks. If 3981 * the endpoint has at least one endpoint pair shared key for the peer, 3982 * it MUST use the key specified by the Shared Key Identifier if a 3983 * key has been configured for that Shared Key Identifier. If no 3984 * endpoint pair shared key has been configured for that Shared Key 3985 * Identifier, all authenticated chunks MUST be silently discarded. 3986 * 3987 * Verification Tag: 8.5 Verification Tag [Normal verification] 3988 * 3989 * The return value is the disposition of the chunk. 3990 */ 3991 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 3992 const struct sctp_endpoint *ep, 3993 const struct sctp_association *asoc, 3994 const sctp_subtype_t type, 3995 struct sctp_chunk *chunk) 3996 { 3997 struct sctp_authhdr *auth_hdr; 3998 struct sctp_hmac *hmac; 3999 unsigned int sig_len; 4000 __u16 key_id; 4001 __u8 *save_digest; 4002 __u8 *digest; 4003 4004 /* Pull in the auth header, so we can do some more verification */ 4005 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4006 chunk->subh.auth_hdr = auth_hdr; 4007 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4008 4009 /* Make sure that we support the HMAC algorithm from the auth 4010 * chunk. 4011 */ 4012 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4013 return SCTP_IERROR_AUTH_BAD_HMAC; 4014 4015 /* Make sure that the provided shared key identifier has been 4016 * configured 4017 */ 4018 key_id = ntohs(auth_hdr->shkey_id); 4019 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4020 return SCTP_IERROR_AUTH_BAD_KEYID; 4021 4022 4023 /* Make sure that the length of the signature matches what 4024 * we expect. 4025 */ 4026 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4027 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4028 if (sig_len != hmac->hmac_len) 4029 return SCTP_IERROR_PROTO_VIOLATION; 4030 4031 /* Now that we've done validation checks, we can compute and 4032 * verify the hmac. The steps involved are: 4033 * 1. Save the digest from the chunk. 4034 * 2. Zero out the digest in the chunk. 4035 * 3. Compute the new digest 4036 * 4. Compare saved and new digests. 4037 */ 4038 digest = auth_hdr->hmac; 4039 skb_pull(chunk->skb, sig_len); 4040 4041 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4042 if (!save_digest) 4043 goto nomem; 4044 4045 memset(digest, 0, sig_len); 4046 4047 sctp_auth_calculate_hmac(asoc, chunk->skb, 4048 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4049 GFP_ATOMIC); 4050 4051 /* Discard the packet if the digests do not match */ 4052 if (memcmp(save_digest, digest, sig_len)) { 4053 kfree(save_digest); 4054 return SCTP_IERROR_BAD_SIG; 4055 } 4056 4057 kfree(save_digest); 4058 chunk->auth = 1; 4059 4060 return SCTP_IERROR_NO_ERROR; 4061 nomem: 4062 return SCTP_IERROR_NOMEM; 4063 } 4064 4065 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4066 const struct sctp_endpoint *ep, 4067 const struct sctp_association *asoc, 4068 const sctp_subtype_t type, 4069 void *arg, 4070 sctp_cmd_seq_t *commands) 4071 { 4072 struct sctp_authhdr *auth_hdr; 4073 struct sctp_chunk *chunk = arg; 4074 struct sctp_chunk *err_chunk; 4075 sctp_ierror_t error; 4076 4077 /* Make sure that the peer has AUTH capable */ 4078 if (!asoc->peer.auth_capable) 4079 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4080 4081 if (!sctp_vtag_verify(chunk, asoc)) { 4082 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4083 SCTP_NULL()); 4084 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4085 } 4086 4087 /* Make sure that the AUTH chunk has valid length. */ 4088 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4089 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4090 commands); 4091 4092 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4093 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4094 switch (error) { 4095 case SCTP_IERROR_AUTH_BAD_HMAC: 4096 /* Generate the ERROR chunk and discard the rest 4097 * of the packet 4098 */ 4099 err_chunk = sctp_make_op_error(asoc, chunk, 4100 SCTP_ERROR_UNSUP_HMAC, 4101 &auth_hdr->hmac_id, 4102 sizeof(__u16), 0); 4103 if (err_chunk) { 4104 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4105 SCTP_CHUNK(err_chunk)); 4106 } 4107 /* Fall Through */ 4108 case SCTP_IERROR_AUTH_BAD_KEYID: 4109 case SCTP_IERROR_BAD_SIG: 4110 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4111 4112 case SCTP_IERROR_PROTO_VIOLATION: 4113 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4114 commands); 4115 4116 case SCTP_IERROR_NOMEM: 4117 return SCTP_DISPOSITION_NOMEM; 4118 4119 default: /* Prevent gcc warnings */ 4120 break; 4121 } 4122 4123 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4124 struct sctp_ulpevent *ev; 4125 4126 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4127 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4128 4129 if (!ev) 4130 return -ENOMEM; 4131 4132 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4133 SCTP_ULPEVENT(ev)); 4134 } 4135 4136 return SCTP_DISPOSITION_CONSUME; 4137 } 4138 4139 /* 4140 * Process an unknown chunk. 4141 * 4142 * Section: 3.2. Also, 2.1 in the implementor's guide. 4143 * 4144 * Chunk Types are encoded such that the highest-order two bits specify 4145 * the action that must be taken if the processing endpoint does not 4146 * recognize the Chunk Type. 4147 * 4148 * 00 - Stop processing this SCTP packet and discard it, do not process 4149 * any further chunks within it. 4150 * 4151 * 01 - Stop processing this SCTP packet and discard it, do not process 4152 * any further chunks within it, and report the unrecognized 4153 * chunk in an 'Unrecognized Chunk Type'. 4154 * 4155 * 10 - Skip this chunk and continue processing. 4156 * 4157 * 11 - Skip this chunk and continue processing, but report in an ERROR 4158 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4159 * 4160 * The return value is the disposition of the chunk. 4161 */ 4162 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4163 const struct sctp_endpoint *ep, 4164 const struct sctp_association *asoc, 4165 const sctp_subtype_t type, 4166 void *arg, 4167 sctp_cmd_seq_t *commands) 4168 { 4169 struct sctp_chunk *unk_chunk = arg; 4170 struct sctp_chunk *err_chunk; 4171 sctp_chunkhdr_t *hdr; 4172 4173 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4174 4175 if (!sctp_vtag_verify(unk_chunk, asoc)) 4176 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4177 4178 /* Make sure that the chunk has a valid length. 4179 * Since we don't know the chunk type, we use a general 4180 * chunkhdr structure to make a comparison. 4181 */ 4182 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4183 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4184 commands); 4185 4186 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4187 case SCTP_CID_ACTION_DISCARD: 4188 /* Discard the packet. */ 4189 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4190 break; 4191 case SCTP_CID_ACTION_DISCARD_ERR: 4192 /* Generate an ERROR chunk as response. */ 4193 hdr = unk_chunk->chunk_hdr; 4194 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4195 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4196 WORD_ROUND(ntohs(hdr->length)), 4197 0); 4198 if (err_chunk) { 4199 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4200 SCTP_CHUNK(err_chunk)); 4201 } 4202 4203 /* Discard the packet. */ 4204 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4205 return SCTP_DISPOSITION_CONSUME; 4206 break; 4207 case SCTP_CID_ACTION_SKIP: 4208 /* Skip the chunk. */ 4209 return SCTP_DISPOSITION_DISCARD; 4210 break; 4211 case SCTP_CID_ACTION_SKIP_ERR: 4212 /* Generate an ERROR chunk as response. */ 4213 hdr = unk_chunk->chunk_hdr; 4214 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4215 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4216 WORD_ROUND(ntohs(hdr->length)), 4217 0); 4218 if (err_chunk) { 4219 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4220 SCTP_CHUNK(err_chunk)); 4221 } 4222 /* Skip the chunk. */ 4223 return SCTP_DISPOSITION_CONSUME; 4224 break; 4225 default: 4226 break; 4227 } 4228 4229 return SCTP_DISPOSITION_DISCARD; 4230 } 4231 4232 /* 4233 * Discard the chunk. 4234 * 4235 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4236 * [Too numerous to mention...] 4237 * Verification Tag: No verification needed. 4238 * Inputs 4239 * (endpoint, asoc, chunk) 4240 * 4241 * Outputs 4242 * (asoc, reply_msg, msg_up, timers, counters) 4243 * 4244 * The return value is the disposition of the chunk. 4245 */ 4246 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4247 const struct sctp_endpoint *ep, 4248 const struct sctp_association *asoc, 4249 const sctp_subtype_t type, 4250 void *arg, 4251 sctp_cmd_seq_t *commands) 4252 { 4253 struct sctp_chunk *chunk = arg; 4254 4255 /* Make sure that the chunk has a valid length. 4256 * Since we don't know the chunk type, we use a general 4257 * chunkhdr structure to make a comparison. 4258 */ 4259 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4260 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4261 commands); 4262 4263 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4264 4265 return SCTP_DISPOSITION_DISCARD; 4266 } 4267 4268 /* 4269 * Discard the whole packet. 4270 * 4271 * Section: 8.4 2) 4272 * 4273 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4274 * silently discard the OOTB packet and take no further action. 4275 * 4276 * Verification Tag: No verification necessary 4277 * 4278 * Inputs 4279 * (endpoint, asoc, chunk) 4280 * 4281 * Outputs 4282 * (asoc, reply_msg, msg_up, timers, counters) 4283 * 4284 * The return value is the disposition of the chunk. 4285 */ 4286 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4287 const struct sctp_endpoint *ep, 4288 const struct sctp_association *asoc, 4289 const sctp_subtype_t type, 4290 void *arg, 4291 sctp_cmd_seq_t *commands) 4292 { 4293 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4294 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4295 4296 return SCTP_DISPOSITION_CONSUME; 4297 } 4298 4299 4300 /* 4301 * The other end is violating protocol. 4302 * 4303 * Section: Not specified 4304 * Verification Tag: Not specified 4305 * Inputs 4306 * (endpoint, asoc, chunk) 4307 * 4308 * Outputs 4309 * (asoc, reply_msg, msg_up, timers, counters) 4310 * 4311 * We simply tag the chunk as a violation. The state machine will log 4312 * the violation and continue. 4313 */ 4314 sctp_disposition_t sctp_sf_violation(struct net *net, 4315 const struct sctp_endpoint *ep, 4316 const struct sctp_association *asoc, 4317 const sctp_subtype_t type, 4318 void *arg, 4319 sctp_cmd_seq_t *commands) 4320 { 4321 struct sctp_chunk *chunk = arg; 4322 4323 /* Make sure that the chunk has a valid length. */ 4324 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4325 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4326 commands); 4327 4328 return SCTP_DISPOSITION_VIOLATION; 4329 } 4330 4331 /* 4332 * Common function to handle a protocol violation. 4333 */ 4334 static sctp_disposition_t sctp_sf_abort_violation( 4335 struct net *net, 4336 const struct sctp_endpoint *ep, 4337 const struct sctp_association *asoc, 4338 void *arg, 4339 sctp_cmd_seq_t *commands, 4340 const __u8 *payload, 4341 const size_t paylen) 4342 { 4343 struct sctp_packet *packet = NULL; 4344 struct sctp_chunk *chunk = arg; 4345 struct sctp_chunk *abort = NULL; 4346 4347 /* SCTP-AUTH, Section 6.3: 4348 * It should be noted that if the receiver wants to tear 4349 * down an association in an authenticated way only, the 4350 * handling of malformed packets should not result in 4351 * tearing down the association. 4352 * 4353 * This means that if we only want to abort associations 4354 * in an authenticated way (i.e AUTH+ABORT), then we 4355 * can't destroy this association just because the packet 4356 * was malformed. 4357 */ 4358 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4359 goto discard; 4360 4361 /* Make the abort chunk. */ 4362 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4363 if (!abort) 4364 goto nomem; 4365 4366 if (asoc) { 4367 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4368 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4369 !asoc->peer.i.init_tag) { 4370 sctp_initack_chunk_t *initack; 4371 4372 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4373 if (!sctp_chunk_length_valid(chunk, 4374 sizeof(sctp_initack_chunk_t))) 4375 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4376 else { 4377 unsigned int inittag; 4378 4379 inittag = ntohl(initack->init_hdr.init_tag); 4380 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4381 SCTP_U32(inittag)); 4382 } 4383 } 4384 4385 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4386 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4387 4388 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4389 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4390 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4391 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4392 SCTP_ERROR(ECONNREFUSED)); 4393 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4394 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4395 } else { 4396 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4397 SCTP_ERROR(ECONNABORTED)); 4398 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4399 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4400 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4401 } 4402 } else { 4403 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4404 4405 if (!packet) 4406 goto nomem_pkt; 4407 4408 if (sctp_test_T_bit(abort)) 4409 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4410 4411 abort->skb->sk = ep->base.sk; 4412 4413 sctp_packet_append_chunk(packet, abort); 4414 4415 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4416 SCTP_PACKET(packet)); 4417 4418 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4419 } 4420 4421 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4422 4423 discard: 4424 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4425 return SCTP_DISPOSITION_ABORT; 4426 4427 nomem_pkt: 4428 sctp_chunk_free(abort); 4429 nomem: 4430 return SCTP_DISPOSITION_NOMEM; 4431 } 4432 4433 /* 4434 * Handle a protocol violation when the chunk length is invalid. 4435 * "Invalid" length is identified as smaller than the minimal length a 4436 * given chunk can be. For example, a SACK chunk has invalid length 4437 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4438 * 4439 * We inform the other end by sending an ABORT with a Protocol Violation 4440 * error code. 4441 * 4442 * Section: Not specified 4443 * Verification Tag: Nothing to do 4444 * Inputs 4445 * (endpoint, asoc, chunk) 4446 * 4447 * Outputs 4448 * (reply_msg, msg_up, counters) 4449 * 4450 * Generate an ABORT chunk and terminate the association. 4451 */ 4452 static sctp_disposition_t sctp_sf_violation_chunklen( 4453 struct net *net, 4454 const struct sctp_endpoint *ep, 4455 const struct sctp_association *asoc, 4456 const sctp_subtype_t type, 4457 void *arg, 4458 sctp_cmd_seq_t *commands) 4459 { 4460 static const char err_str[] = "The following chunk had invalid length:"; 4461 4462 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4463 sizeof(err_str)); 4464 } 4465 4466 /* 4467 * Handle a protocol violation when the parameter length is invalid. 4468 * If the length is smaller than the minimum length of a given parameter, 4469 * or accumulated length in multi parameters exceeds the end of the chunk, 4470 * the length is considered as invalid. 4471 */ 4472 static sctp_disposition_t sctp_sf_violation_paramlen( 4473 struct net *net, 4474 const struct sctp_endpoint *ep, 4475 const struct sctp_association *asoc, 4476 const sctp_subtype_t type, 4477 void *arg, void *ext, 4478 sctp_cmd_seq_t *commands) 4479 { 4480 struct sctp_chunk *chunk = arg; 4481 struct sctp_paramhdr *param = ext; 4482 struct sctp_chunk *abort = NULL; 4483 4484 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4485 goto discard; 4486 4487 /* Make the abort chunk. */ 4488 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4489 if (!abort) 4490 goto nomem; 4491 4492 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4493 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4494 4495 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4496 SCTP_ERROR(ECONNABORTED)); 4497 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4498 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4499 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4500 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4501 4502 discard: 4503 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4504 return SCTP_DISPOSITION_ABORT; 4505 nomem: 4506 return SCTP_DISPOSITION_NOMEM; 4507 } 4508 4509 /* Handle a protocol violation when the peer trying to advance the 4510 * cumulative tsn ack to a point beyond the max tsn currently sent. 4511 * 4512 * We inform the other end by sending an ABORT with a Protocol Violation 4513 * error code. 4514 */ 4515 static sctp_disposition_t sctp_sf_violation_ctsn( 4516 struct net *net, 4517 const struct sctp_endpoint *ep, 4518 const struct sctp_association *asoc, 4519 const sctp_subtype_t type, 4520 void *arg, 4521 sctp_cmd_seq_t *commands) 4522 { 4523 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4524 4525 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4526 sizeof(err_str)); 4527 } 4528 4529 /* Handle protocol violation of an invalid chunk bundling. For example, 4530 * when we have an association and we receive bundled INIT-ACK, or 4531 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4532 * statement from the specs. Additionally, there might be an attacker 4533 * on the path and we may not want to continue this communication. 4534 */ 4535 static sctp_disposition_t sctp_sf_violation_chunk( 4536 struct net *net, 4537 const struct sctp_endpoint *ep, 4538 const struct sctp_association *asoc, 4539 const sctp_subtype_t type, 4540 void *arg, 4541 sctp_cmd_seq_t *commands) 4542 { 4543 static const char err_str[] = "The following chunk violates protocol:"; 4544 4545 if (!asoc) 4546 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4547 4548 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4549 sizeof(err_str)); 4550 } 4551 /*************************************************************************** 4552 * These are the state functions for handling primitive (Section 10) events. 4553 ***************************************************************************/ 4554 /* 4555 * sctp_sf_do_prm_asoc 4556 * 4557 * Section: 10.1 ULP-to-SCTP 4558 * B) Associate 4559 * 4560 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4561 * outbound stream count) 4562 * -> association id [,destination transport addr list] [,outbound stream 4563 * count] 4564 * 4565 * This primitive allows the upper layer to initiate an association to a 4566 * specific peer endpoint. 4567 * 4568 * The peer endpoint shall be specified by one of the transport addresses 4569 * which defines the endpoint (see Section 1.4). If the local SCTP 4570 * instance has not been initialized, the ASSOCIATE is considered an 4571 * error. 4572 * [This is not relevant for the kernel implementation since we do all 4573 * initialization at boot time. It we hadn't initialized we wouldn't 4574 * get anywhere near this code.] 4575 * 4576 * An association id, which is a local handle to the SCTP association, 4577 * will be returned on successful establishment of the association. If 4578 * SCTP is not able to open an SCTP association with the peer endpoint, 4579 * an error is returned. 4580 * [In the kernel implementation, the struct sctp_association needs to 4581 * be created BEFORE causing this primitive to run.] 4582 * 4583 * Other association parameters may be returned, including the 4584 * complete destination transport addresses of the peer as well as the 4585 * outbound stream count of the local endpoint. One of the transport 4586 * address from the returned destination addresses will be selected by 4587 * the local endpoint as default primary path for sending SCTP packets 4588 * to this peer. The returned "destination transport addr list" can 4589 * be used by the ULP to change the default primary path or to force 4590 * sending a packet to a specific transport address. [All of this 4591 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4592 * function.] 4593 * 4594 * Mandatory attributes: 4595 * 4596 * o local SCTP instance name - obtained from the INITIALIZE operation. 4597 * [This is the argument asoc.] 4598 * o destination transport addr - specified as one of the transport 4599 * addresses of the peer endpoint with which the association is to be 4600 * established. 4601 * [This is asoc->peer.active_path.] 4602 * o outbound stream count - the number of outbound streams the ULP 4603 * would like to open towards this peer endpoint. 4604 * [BUG: This is not currently implemented.] 4605 * Optional attributes: 4606 * 4607 * None. 4608 * 4609 * The return value is a disposition. 4610 */ 4611 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4612 const struct sctp_endpoint *ep, 4613 const struct sctp_association *asoc, 4614 const sctp_subtype_t type, 4615 void *arg, 4616 sctp_cmd_seq_t *commands) 4617 { 4618 struct sctp_chunk *repl; 4619 struct sctp_association *my_asoc; 4620 4621 /* The comment below says that we enter COOKIE-WAIT AFTER 4622 * sending the INIT, but that doesn't actually work in our 4623 * implementation... 4624 */ 4625 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4626 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4627 4628 /* RFC 2960 5.1 Normal Establishment of an Association 4629 * 4630 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4631 * must provide its Verification Tag (Tag_A) in the Initiate 4632 * Tag field. Tag_A SHOULD be a random number in the range of 4633 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4634 */ 4635 4636 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4637 if (!repl) 4638 goto nomem; 4639 4640 /* Choose transport for INIT. */ 4641 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4642 SCTP_CHUNK(repl)); 4643 4644 /* Cast away the const modifier, as we want to just 4645 * rerun it through as a sideffect. 4646 */ 4647 my_asoc = (struct sctp_association *)asoc; 4648 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4649 4650 /* After sending the INIT, "A" starts the T1-init timer and 4651 * enters the COOKIE-WAIT state. 4652 */ 4653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4654 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4655 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4656 return SCTP_DISPOSITION_CONSUME; 4657 4658 nomem: 4659 return SCTP_DISPOSITION_NOMEM; 4660 } 4661 4662 /* 4663 * Process the SEND primitive. 4664 * 4665 * Section: 10.1 ULP-to-SCTP 4666 * E) Send 4667 * 4668 * Format: SEND(association id, buffer address, byte count [,context] 4669 * [,stream id] [,life time] [,destination transport address] 4670 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4671 * -> result 4672 * 4673 * This is the main method to send user data via SCTP. 4674 * 4675 * Mandatory attributes: 4676 * 4677 * o association id - local handle to the SCTP association 4678 * 4679 * o buffer address - the location where the user message to be 4680 * transmitted is stored; 4681 * 4682 * o byte count - The size of the user data in number of bytes; 4683 * 4684 * Optional attributes: 4685 * 4686 * o context - an optional 32 bit integer that will be carried in the 4687 * sending failure notification to the ULP if the transportation of 4688 * this User Message fails. 4689 * 4690 * o stream id - to indicate which stream to send the data on. If not 4691 * specified, stream 0 will be used. 4692 * 4693 * o life time - specifies the life time of the user data. The user data 4694 * will not be sent by SCTP after the life time expires. This 4695 * parameter can be used to avoid efforts to transmit stale 4696 * user messages. SCTP notifies the ULP if the data cannot be 4697 * initiated to transport (i.e. sent to the destination via SCTP's 4698 * send primitive) within the life time variable. However, the 4699 * user data will be transmitted if SCTP has attempted to transmit a 4700 * chunk before the life time expired. 4701 * 4702 * o destination transport address - specified as one of the destination 4703 * transport addresses of the peer endpoint to which this packet 4704 * should be sent. Whenever possible, SCTP should use this destination 4705 * transport address for sending the packets, instead of the current 4706 * primary path. 4707 * 4708 * o unorder flag - this flag, if present, indicates that the user 4709 * would like the data delivered in an unordered fashion to the peer 4710 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4711 * message). 4712 * 4713 * o no-bundle flag - instructs SCTP not to bundle this user data with 4714 * other outbound DATA chunks. SCTP MAY still bundle even when 4715 * this flag is present, when faced with network congestion. 4716 * 4717 * o payload protocol-id - A 32 bit unsigned integer that is to be 4718 * passed to the peer indicating the type of payload protocol data 4719 * being transmitted. This value is passed as opaque data by SCTP. 4720 * 4721 * The return value is the disposition. 4722 */ 4723 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4724 const struct sctp_endpoint *ep, 4725 const struct sctp_association *asoc, 4726 const sctp_subtype_t type, 4727 void *arg, 4728 sctp_cmd_seq_t *commands) 4729 { 4730 struct sctp_datamsg *msg = arg; 4731 4732 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4733 return SCTP_DISPOSITION_CONSUME; 4734 } 4735 4736 /* 4737 * Process the SHUTDOWN primitive. 4738 * 4739 * Section: 10.1: 4740 * C) Shutdown 4741 * 4742 * Format: SHUTDOWN(association id) 4743 * -> result 4744 * 4745 * Gracefully closes an association. Any locally queued user data 4746 * will be delivered to the peer. The association will be terminated only 4747 * after the peer acknowledges all the SCTP packets sent. A success code 4748 * will be returned on successful termination of the association. If 4749 * attempting to terminate the association results in a failure, an error 4750 * code shall be returned. 4751 * 4752 * Mandatory attributes: 4753 * 4754 * o association id - local handle to the SCTP association 4755 * 4756 * Optional attributes: 4757 * 4758 * None. 4759 * 4760 * The return value is the disposition. 4761 */ 4762 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4763 struct net *net, 4764 const struct sctp_endpoint *ep, 4765 const struct sctp_association *asoc, 4766 const sctp_subtype_t type, 4767 void *arg, 4768 sctp_cmd_seq_t *commands) 4769 { 4770 int disposition; 4771 4772 /* From 9.2 Shutdown of an Association 4773 * Upon receipt of the SHUTDOWN primitive from its upper 4774 * layer, the endpoint enters SHUTDOWN-PENDING state and 4775 * remains there until all outstanding data has been 4776 * acknowledged by its peer. The endpoint accepts no new data 4777 * from its upper layer, but retransmits data to the far end 4778 * if necessary to fill gaps. 4779 */ 4780 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4781 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4782 4783 disposition = SCTP_DISPOSITION_CONSUME; 4784 if (sctp_outq_is_empty(&asoc->outqueue)) { 4785 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4786 arg, commands); 4787 } 4788 return disposition; 4789 } 4790 4791 /* 4792 * Process the ABORT primitive. 4793 * 4794 * Section: 10.1: 4795 * C) Abort 4796 * 4797 * Format: Abort(association id [, cause code]) 4798 * -> result 4799 * 4800 * Ungracefully closes an association. Any locally queued user data 4801 * will be discarded and an ABORT chunk is sent to the peer. A success code 4802 * will be returned on successful abortion of the association. If 4803 * attempting to abort the association results in a failure, an error 4804 * code shall be returned. 4805 * 4806 * Mandatory attributes: 4807 * 4808 * o association id - local handle to the SCTP association 4809 * 4810 * Optional attributes: 4811 * 4812 * o cause code - reason of the abort to be passed to the peer 4813 * 4814 * None. 4815 * 4816 * The return value is the disposition. 4817 */ 4818 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4819 struct net *net, 4820 const struct sctp_endpoint *ep, 4821 const struct sctp_association *asoc, 4822 const sctp_subtype_t type, 4823 void *arg, 4824 sctp_cmd_seq_t *commands) 4825 { 4826 /* From 9.1 Abort of an Association 4827 * Upon receipt of the ABORT primitive from its upper 4828 * layer, the endpoint enters CLOSED state and 4829 * discard all outstanding data has been 4830 * acknowledged by its peer. The endpoint accepts no new data 4831 * from its upper layer, but retransmits data to the far end 4832 * if necessary to fill gaps. 4833 */ 4834 struct sctp_chunk *abort = arg; 4835 sctp_disposition_t retval; 4836 4837 retval = SCTP_DISPOSITION_CONSUME; 4838 4839 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4840 4841 /* Even if we can't send the ABORT due to low memory delete the 4842 * TCB. This is a departure from our typical NOMEM handling. 4843 */ 4844 4845 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4846 SCTP_ERROR(ECONNABORTED)); 4847 /* Delete the established association. */ 4848 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4849 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4850 4851 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4852 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4853 4854 return retval; 4855 } 4856 4857 /* We tried an illegal operation on an association which is closed. */ 4858 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4859 const struct sctp_endpoint *ep, 4860 const struct sctp_association *asoc, 4861 const sctp_subtype_t type, 4862 void *arg, 4863 sctp_cmd_seq_t *commands) 4864 { 4865 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4866 return SCTP_DISPOSITION_CONSUME; 4867 } 4868 4869 /* We tried an illegal operation on an association which is shutting 4870 * down. 4871 */ 4872 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4873 const struct sctp_endpoint *ep, 4874 const struct sctp_association *asoc, 4875 const sctp_subtype_t type, 4876 void *arg, 4877 sctp_cmd_seq_t *commands) 4878 { 4879 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4880 SCTP_ERROR(-ESHUTDOWN)); 4881 return SCTP_DISPOSITION_CONSUME; 4882 } 4883 4884 /* 4885 * sctp_cookie_wait_prm_shutdown 4886 * 4887 * Section: 4 Note: 2 4888 * Verification Tag: 4889 * Inputs 4890 * (endpoint, asoc) 4891 * 4892 * The RFC does not explicitly address this issue, but is the route through the 4893 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4894 * 4895 * Outputs 4896 * (timers) 4897 */ 4898 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4899 struct net *net, 4900 const struct sctp_endpoint *ep, 4901 const struct sctp_association *asoc, 4902 const sctp_subtype_t type, 4903 void *arg, 4904 sctp_cmd_seq_t *commands) 4905 { 4906 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4907 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4908 4909 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4910 SCTP_STATE(SCTP_STATE_CLOSED)); 4911 4912 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4913 4914 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4915 4916 return SCTP_DISPOSITION_DELETE_TCB; 4917 } 4918 4919 /* 4920 * sctp_cookie_echoed_prm_shutdown 4921 * 4922 * Section: 4 Note: 2 4923 * Verification Tag: 4924 * Inputs 4925 * (endpoint, asoc) 4926 * 4927 * The RFC does not explcitly address this issue, but is the route through the 4928 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4929 * 4930 * Outputs 4931 * (timers) 4932 */ 4933 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4934 struct net *net, 4935 const struct sctp_endpoint *ep, 4936 const struct sctp_association *asoc, 4937 const sctp_subtype_t type, 4938 void *arg, sctp_cmd_seq_t *commands) 4939 { 4940 /* There is a single T1 timer, so we should be able to use 4941 * common function with the COOKIE-WAIT state. 4942 */ 4943 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 4944 } 4945 4946 /* 4947 * sctp_sf_cookie_wait_prm_abort 4948 * 4949 * Section: 4 Note: 2 4950 * Verification Tag: 4951 * Inputs 4952 * (endpoint, asoc) 4953 * 4954 * The RFC does not explicitly address this issue, but is the route through the 4955 * state table when someone issues an abort while in COOKIE_WAIT state. 4956 * 4957 * Outputs 4958 * (timers) 4959 */ 4960 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4961 struct net *net, 4962 const struct sctp_endpoint *ep, 4963 const struct sctp_association *asoc, 4964 const sctp_subtype_t type, 4965 void *arg, 4966 sctp_cmd_seq_t *commands) 4967 { 4968 struct sctp_chunk *abort = arg; 4969 sctp_disposition_t retval; 4970 4971 /* Stop T1-init timer */ 4972 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4973 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4974 retval = SCTP_DISPOSITION_CONSUME; 4975 4976 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4977 4978 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4979 SCTP_STATE(SCTP_STATE_CLOSED)); 4980 4981 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4982 4983 /* Even if we can't send the ABORT due to low memory delete the 4984 * TCB. This is a departure from our typical NOMEM handling. 4985 */ 4986 4987 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4988 SCTP_ERROR(ECONNREFUSED)); 4989 /* Delete the established association. */ 4990 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4991 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4992 4993 return retval; 4994 } 4995 4996 /* 4997 * sctp_sf_cookie_echoed_prm_abort 4998 * 4999 * Section: 4 Note: 3 5000 * Verification Tag: 5001 * Inputs 5002 * (endpoint, asoc) 5003 * 5004 * The RFC does not explcitly address this issue, but is the route through the 5005 * state table when someone issues an abort while in COOKIE_ECHOED state. 5006 * 5007 * Outputs 5008 * (timers) 5009 */ 5010 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 5011 struct net *net, 5012 const struct sctp_endpoint *ep, 5013 const struct sctp_association *asoc, 5014 const sctp_subtype_t type, 5015 void *arg, 5016 sctp_cmd_seq_t *commands) 5017 { 5018 /* There is a single T1 timer, so we should be able to use 5019 * common function with the COOKIE-WAIT state. 5020 */ 5021 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5022 } 5023 5024 /* 5025 * sctp_sf_shutdown_pending_prm_abort 5026 * 5027 * Inputs 5028 * (endpoint, asoc) 5029 * 5030 * The RFC does not explicitly address this issue, but is the route through the 5031 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5032 * 5033 * Outputs 5034 * (timers) 5035 */ 5036 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5037 struct net *net, 5038 const struct sctp_endpoint *ep, 5039 const struct sctp_association *asoc, 5040 const sctp_subtype_t type, 5041 void *arg, 5042 sctp_cmd_seq_t *commands) 5043 { 5044 /* Stop the T5-shutdown guard timer. */ 5045 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5046 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5047 5048 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5049 } 5050 5051 /* 5052 * sctp_sf_shutdown_sent_prm_abort 5053 * 5054 * Inputs 5055 * (endpoint, asoc) 5056 * 5057 * The RFC does not explicitly address this issue, but is the route through the 5058 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5059 * 5060 * Outputs 5061 * (timers) 5062 */ 5063 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5064 struct net *net, 5065 const struct sctp_endpoint *ep, 5066 const struct sctp_association *asoc, 5067 const sctp_subtype_t type, 5068 void *arg, 5069 sctp_cmd_seq_t *commands) 5070 { 5071 /* Stop the T2-shutdown timer. */ 5072 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5073 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5074 5075 /* Stop the T5-shutdown guard timer. */ 5076 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5077 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5078 5079 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5080 } 5081 5082 /* 5083 * sctp_sf_cookie_echoed_prm_abort 5084 * 5085 * Inputs 5086 * (endpoint, asoc) 5087 * 5088 * The RFC does not explcitly address this issue, but is the route through the 5089 * state table when someone issues an abort while in COOKIE_ECHOED state. 5090 * 5091 * Outputs 5092 * (timers) 5093 */ 5094 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5095 struct net *net, 5096 const struct sctp_endpoint *ep, 5097 const struct sctp_association *asoc, 5098 const sctp_subtype_t type, 5099 void *arg, 5100 sctp_cmd_seq_t *commands) 5101 { 5102 /* The same T2 timer, so we should be able to use 5103 * common function with the SHUTDOWN-SENT state. 5104 */ 5105 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5106 } 5107 5108 /* 5109 * Process the REQUESTHEARTBEAT primitive 5110 * 5111 * 10.1 ULP-to-SCTP 5112 * J) Request Heartbeat 5113 * 5114 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5115 * 5116 * -> result 5117 * 5118 * Instructs the local endpoint to perform a HeartBeat on the specified 5119 * destination transport address of the given association. The returned 5120 * result should indicate whether the transmission of the HEARTBEAT 5121 * chunk to the destination address is successful. 5122 * 5123 * Mandatory attributes: 5124 * 5125 * o association id - local handle to the SCTP association 5126 * 5127 * o destination transport address - the transport address of the 5128 * association on which a heartbeat should be issued. 5129 */ 5130 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5131 struct net *net, 5132 const struct sctp_endpoint *ep, 5133 const struct sctp_association *asoc, 5134 const sctp_subtype_t type, 5135 void *arg, 5136 sctp_cmd_seq_t *commands) 5137 { 5138 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5139 (struct sctp_transport *)arg, commands)) 5140 return SCTP_DISPOSITION_NOMEM; 5141 5142 /* 5143 * RFC 2960 (bis), section 8.3 5144 * 5145 * D) Request an on-demand HEARTBEAT on a specific destination 5146 * transport address of a given association. 5147 * 5148 * The endpoint should increment the respective error counter of 5149 * the destination transport address each time a HEARTBEAT is sent 5150 * to that address and not acknowledged within one RTO. 5151 * 5152 */ 5153 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5154 SCTP_TRANSPORT(arg)); 5155 return SCTP_DISPOSITION_CONSUME; 5156 } 5157 5158 /* 5159 * ADDIP Section 4.1 ASCONF Chunk Procedures 5160 * When an endpoint has an ASCONF signaled change to be sent to the 5161 * remote endpoint it should do A1 to A9 5162 */ 5163 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5164 const struct sctp_endpoint *ep, 5165 const struct sctp_association *asoc, 5166 const sctp_subtype_t type, 5167 void *arg, 5168 sctp_cmd_seq_t *commands) 5169 { 5170 struct sctp_chunk *chunk = arg; 5171 5172 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5173 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5174 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5175 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5176 return SCTP_DISPOSITION_CONSUME; 5177 } 5178 5179 /* 5180 * Ignore the primitive event 5181 * 5182 * The return value is the disposition of the primitive. 5183 */ 5184 sctp_disposition_t sctp_sf_ignore_primitive( 5185 struct net *net, 5186 const struct sctp_endpoint *ep, 5187 const struct sctp_association *asoc, 5188 const sctp_subtype_t type, 5189 void *arg, 5190 sctp_cmd_seq_t *commands) 5191 { 5192 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5193 type.primitive); 5194 5195 return SCTP_DISPOSITION_DISCARD; 5196 } 5197 5198 /*************************************************************************** 5199 * These are the state functions for the OTHER events. 5200 ***************************************************************************/ 5201 5202 /* 5203 * When the SCTP stack has no more user data to send or retransmit, this 5204 * notification is given to the user. Also, at the time when a user app 5205 * subscribes to this event, if there is no data to be sent or 5206 * retransmit, the stack will immediately send up this notification. 5207 */ 5208 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5209 struct net *net, 5210 const struct sctp_endpoint *ep, 5211 const struct sctp_association *asoc, 5212 const sctp_subtype_t type, 5213 void *arg, 5214 sctp_cmd_seq_t *commands) 5215 { 5216 struct sctp_ulpevent *event; 5217 5218 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5219 if (!event) 5220 return SCTP_DISPOSITION_NOMEM; 5221 5222 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5223 5224 return SCTP_DISPOSITION_CONSUME; 5225 } 5226 5227 /* 5228 * Start the shutdown negotiation. 5229 * 5230 * From Section 9.2: 5231 * Once all its outstanding data has been acknowledged, the endpoint 5232 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5233 * TSN Ack field the last sequential TSN it has received from the peer. 5234 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5235 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5236 * with the updated last sequential TSN received from its peer. 5237 * 5238 * The return value is the disposition. 5239 */ 5240 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5241 struct net *net, 5242 const struct sctp_endpoint *ep, 5243 const struct sctp_association *asoc, 5244 const sctp_subtype_t type, 5245 void *arg, 5246 sctp_cmd_seq_t *commands) 5247 { 5248 struct sctp_chunk *reply; 5249 5250 /* Once all its outstanding data has been acknowledged, the 5251 * endpoint shall send a SHUTDOWN chunk to its peer including 5252 * in the Cumulative TSN Ack field the last sequential TSN it 5253 * has received from the peer. 5254 */ 5255 reply = sctp_make_shutdown(asoc, NULL); 5256 if (!reply) 5257 goto nomem; 5258 5259 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5260 * T2-shutdown timer. 5261 */ 5262 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5263 5264 /* It shall then start the T2-shutdown timer */ 5265 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5266 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5267 5268 /* RFC 4960 Section 9.2 5269 * The sender of the SHUTDOWN MAY also start an overall guard timer 5270 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5271 */ 5272 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5273 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5274 5275 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5276 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5277 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5278 5279 /* and enter the SHUTDOWN-SENT state. */ 5280 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5281 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5282 5283 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5284 * 5285 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5286 * or SHUTDOWN-ACK. 5287 */ 5288 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5289 5290 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5291 5292 return SCTP_DISPOSITION_CONSUME; 5293 5294 nomem: 5295 return SCTP_DISPOSITION_NOMEM; 5296 } 5297 5298 /* 5299 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5300 * 5301 * From Section 9.2: 5302 * 5303 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5304 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5305 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5306 * endpoint must re-send the SHUTDOWN ACK. 5307 * 5308 * The return value is the disposition. 5309 */ 5310 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5311 struct net *net, 5312 const struct sctp_endpoint *ep, 5313 const struct sctp_association *asoc, 5314 const sctp_subtype_t type, 5315 void *arg, 5316 sctp_cmd_seq_t *commands) 5317 { 5318 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5319 struct sctp_chunk *reply; 5320 5321 /* There are 2 ways of getting here: 5322 * 1) called in response to a SHUTDOWN chunk 5323 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5324 * 5325 * For the case (2), the arg parameter is set to NULL. We need 5326 * to check that we have a chunk before accessing it's fields. 5327 */ 5328 if (chunk) { 5329 if (!sctp_vtag_verify(chunk, asoc)) 5330 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5331 5332 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5333 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5334 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5335 commands); 5336 } 5337 5338 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5339 * shall send a SHUTDOWN ACK ... 5340 */ 5341 reply = sctp_make_shutdown_ack(asoc, chunk); 5342 if (!reply) 5343 goto nomem; 5344 5345 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5346 * the T2-shutdown timer. 5347 */ 5348 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5349 5350 /* and start/restart a T2-shutdown timer of its own, */ 5351 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5352 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5353 5354 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5355 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5356 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5357 5358 /* Enter the SHUTDOWN-ACK-SENT state. */ 5359 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5360 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5361 5362 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5363 * 5364 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5365 * or SHUTDOWN-ACK. 5366 */ 5367 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5368 5369 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5370 5371 return SCTP_DISPOSITION_CONSUME; 5372 5373 nomem: 5374 return SCTP_DISPOSITION_NOMEM; 5375 } 5376 5377 /* 5378 * Ignore the event defined as other 5379 * 5380 * The return value is the disposition of the event. 5381 */ 5382 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5383 const struct sctp_endpoint *ep, 5384 const struct sctp_association *asoc, 5385 const sctp_subtype_t type, 5386 void *arg, 5387 sctp_cmd_seq_t *commands) 5388 { 5389 pr_debug("%s: the event other type:%d is ignored\n", 5390 __func__, type.other); 5391 5392 return SCTP_DISPOSITION_DISCARD; 5393 } 5394 5395 /************************************************************ 5396 * These are the state functions for handling timeout events. 5397 ************************************************************/ 5398 5399 /* 5400 * RTX Timeout 5401 * 5402 * Section: 6.3.3 Handle T3-rtx Expiration 5403 * 5404 * Whenever the retransmission timer T3-rtx expires for a destination 5405 * address, do the following: 5406 * [See below] 5407 * 5408 * The return value is the disposition of the chunk. 5409 */ 5410 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5411 const struct sctp_endpoint *ep, 5412 const struct sctp_association *asoc, 5413 const sctp_subtype_t type, 5414 void *arg, 5415 sctp_cmd_seq_t *commands) 5416 { 5417 struct sctp_transport *transport = arg; 5418 5419 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5420 5421 if (asoc->overall_error_count >= asoc->max_retrans) { 5422 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5423 /* 5424 * We are here likely because the receiver had its rwnd 5425 * closed for a while and we have not been able to 5426 * transmit the locally queued data within the maximum 5427 * retransmission attempts limit. Start the T5 5428 * shutdown guard timer to give the receiver one last 5429 * chance and some additional time to recover before 5430 * aborting. 5431 */ 5432 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5433 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5434 } else { 5435 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5436 SCTP_ERROR(ETIMEDOUT)); 5437 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5438 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5439 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5440 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5441 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5442 return SCTP_DISPOSITION_DELETE_TCB; 5443 } 5444 } 5445 5446 /* E1) For the destination address for which the timer 5447 * expires, adjust its ssthresh with rules defined in Section 5448 * 7.2.3 and set the cwnd <- MTU. 5449 */ 5450 5451 /* E2) For the destination address for which the timer 5452 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5453 * maximum value discussed in rule C7 above (RTO.max) may be 5454 * used to provide an upper bound to this doubling operation. 5455 */ 5456 5457 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5458 * outstanding DATA chunks for the address for which the 5459 * T3-rtx has expired will fit into a single packet, subject 5460 * to the MTU constraint for the path corresponding to the 5461 * destination transport address to which the retransmission 5462 * is being sent (this may be different from the address for 5463 * which the timer expires [see Section 6.4]). Call this 5464 * value K. Bundle and retransmit those K DATA chunks in a 5465 * single packet to the destination endpoint. 5466 * 5467 * Note: Any DATA chunks that were sent to the address for 5468 * which the T3-rtx timer expired but did not fit in one MTU 5469 * (rule E3 above), should be marked for retransmission and 5470 * sent as soon as cwnd allows (normally when a SACK arrives). 5471 */ 5472 5473 /* Do some failure management (Section 8.2). */ 5474 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5475 5476 /* NB: Rules E4 and F1 are implicit in R1. */ 5477 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5478 5479 return SCTP_DISPOSITION_CONSUME; 5480 } 5481 5482 /* 5483 * Generate delayed SACK on timeout 5484 * 5485 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5486 * 5487 * The guidelines on delayed acknowledgement algorithm specified in 5488 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5489 * acknowledgement SHOULD be generated for at least every second packet 5490 * (not every second DATA chunk) received, and SHOULD be generated 5491 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5492 * some situations it may be beneficial for an SCTP transmitter to be 5493 * more conservative than the algorithms detailed in this document 5494 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5495 * the following algorithms allow. 5496 */ 5497 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5498 const struct sctp_endpoint *ep, 5499 const struct sctp_association *asoc, 5500 const sctp_subtype_t type, 5501 void *arg, 5502 sctp_cmd_seq_t *commands) 5503 { 5504 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5505 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5506 return SCTP_DISPOSITION_CONSUME; 5507 } 5508 5509 /* 5510 * sctp_sf_t1_init_timer_expire 5511 * 5512 * Section: 4 Note: 2 5513 * Verification Tag: 5514 * Inputs 5515 * (endpoint, asoc) 5516 * 5517 * RFC 2960 Section 4 Notes 5518 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5519 * and re-start the T1-init timer without changing state. This MUST 5520 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5521 * endpoint MUST abort the initialization process and report the 5522 * error to SCTP user. 5523 * 5524 * Outputs 5525 * (timers, events) 5526 * 5527 */ 5528 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5529 const struct sctp_endpoint *ep, 5530 const struct sctp_association *asoc, 5531 const sctp_subtype_t type, 5532 void *arg, 5533 sctp_cmd_seq_t *commands) 5534 { 5535 struct sctp_chunk *repl = NULL; 5536 struct sctp_bind_addr *bp; 5537 int attempts = asoc->init_err_counter + 1; 5538 5539 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5540 5541 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5542 5543 if (attempts <= asoc->max_init_attempts) { 5544 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5545 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5546 if (!repl) 5547 return SCTP_DISPOSITION_NOMEM; 5548 5549 /* Choose transport for INIT. */ 5550 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5551 SCTP_CHUNK(repl)); 5552 5553 /* Issue a sideeffect to do the needed accounting. */ 5554 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5555 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5556 5557 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5558 } else { 5559 pr_debug("%s: giving up on INIT, attempts:%d " 5560 "max_init_attempts:%d\n", __func__, attempts, 5561 asoc->max_init_attempts); 5562 5563 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5564 SCTP_ERROR(ETIMEDOUT)); 5565 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5566 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5567 return SCTP_DISPOSITION_DELETE_TCB; 5568 } 5569 5570 return SCTP_DISPOSITION_CONSUME; 5571 } 5572 5573 /* 5574 * sctp_sf_t1_cookie_timer_expire 5575 * 5576 * Section: 4 Note: 2 5577 * Verification Tag: 5578 * Inputs 5579 * (endpoint, asoc) 5580 * 5581 * RFC 2960 Section 4 Notes 5582 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5583 * COOKIE ECHO and re-start the T1-cookie timer without changing 5584 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5585 * After that, the endpoint MUST abort the initialization process and 5586 * report the error to SCTP user. 5587 * 5588 * Outputs 5589 * (timers, events) 5590 * 5591 */ 5592 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5593 const struct sctp_endpoint *ep, 5594 const struct sctp_association *asoc, 5595 const sctp_subtype_t type, 5596 void *arg, 5597 sctp_cmd_seq_t *commands) 5598 { 5599 struct sctp_chunk *repl = NULL; 5600 int attempts = asoc->init_err_counter + 1; 5601 5602 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5603 5604 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5605 5606 if (attempts <= asoc->max_init_attempts) { 5607 repl = sctp_make_cookie_echo(asoc, NULL); 5608 if (!repl) 5609 return SCTP_DISPOSITION_NOMEM; 5610 5611 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5612 SCTP_CHUNK(repl)); 5613 /* Issue a sideeffect to do the needed accounting. */ 5614 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5615 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5616 5617 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5618 } else { 5619 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5620 SCTP_ERROR(ETIMEDOUT)); 5621 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5622 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5623 return SCTP_DISPOSITION_DELETE_TCB; 5624 } 5625 5626 return SCTP_DISPOSITION_CONSUME; 5627 } 5628 5629 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5630 * with the updated last sequential TSN received from its peer. 5631 * 5632 * An endpoint should limit the number of retransmissions of the 5633 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5634 * If this threshold is exceeded the endpoint should destroy the TCB and 5635 * MUST report the peer endpoint unreachable to the upper layer (and 5636 * thus the association enters the CLOSED state). The reception of any 5637 * packet from its peer (i.e. as the peer sends all of its queued DATA 5638 * chunks) should clear the endpoint's retransmission count and restart 5639 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5640 * all of its queued DATA chunks that have not yet been sent. 5641 */ 5642 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5643 const struct sctp_endpoint *ep, 5644 const struct sctp_association *asoc, 5645 const sctp_subtype_t type, 5646 void *arg, 5647 sctp_cmd_seq_t *commands) 5648 { 5649 struct sctp_chunk *reply = NULL; 5650 5651 pr_debug("%s: timer T2 expired\n", __func__); 5652 5653 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5654 5655 ((struct sctp_association *)asoc)->shutdown_retries++; 5656 5657 if (asoc->overall_error_count >= asoc->max_retrans) { 5658 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5659 SCTP_ERROR(ETIMEDOUT)); 5660 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5661 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5662 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5663 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5664 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5665 return SCTP_DISPOSITION_DELETE_TCB; 5666 } 5667 5668 switch (asoc->state) { 5669 case SCTP_STATE_SHUTDOWN_SENT: 5670 reply = sctp_make_shutdown(asoc, NULL); 5671 break; 5672 5673 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5674 reply = sctp_make_shutdown_ack(asoc, NULL); 5675 break; 5676 5677 default: 5678 BUG(); 5679 break; 5680 } 5681 5682 if (!reply) 5683 goto nomem; 5684 5685 /* Do some failure management (Section 8.2). 5686 * If we remove the transport an SHUTDOWN was last sent to, don't 5687 * do failure management. 5688 */ 5689 if (asoc->shutdown_last_sent_to) 5690 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5691 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5692 5693 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5694 * the T2-shutdown timer. 5695 */ 5696 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5697 5698 /* Restart the T2-shutdown timer. */ 5699 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5700 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5701 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5702 return SCTP_DISPOSITION_CONSUME; 5703 5704 nomem: 5705 return SCTP_DISPOSITION_NOMEM; 5706 } 5707 5708 /* 5709 * ADDIP Section 4.1 ASCONF CHunk Procedures 5710 * If the T4 RTO timer expires the endpoint should do B1 to B5 5711 */ 5712 sctp_disposition_t sctp_sf_t4_timer_expire( 5713 struct net *net, 5714 const struct sctp_endpoint *ep, 5715 const struct sctp_association *asoc, 5716 const sctp_subtype_t type, 5717 void *arg, 5718 sctp_cmd_seq_t *commands) 5719 { 5720 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5721 struct sctp_transport *transport = chunk->transport; 5722 5723 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5724 5725 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5726 * detection on the appropriate destination address as defined in 5727 * RFC2960 [5] section 8.1 and 8.2. 5728 */ 5729 if (transport) 5730 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5731 SCTP_TRANSPORT(transport)); 5732 5733 /* Reconfig T4 timer and transport. */ 5734 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5735 5736 /* ADDIP 4.1 B2) Increment the association error counters and perform 5737 * endpoint failure detection on the association as defined in 5738 * RFC2960 [5] section 8.1 and 8.2. 5739 * association error counter is incremented in SCTP_CMD_STRIKE. 5740 */ 5741 if (asoc->overall_error_count >= asoc->max_retrans) { 5742 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5743 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5744 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5745 SCTP_ERROR(ETIMEDOUT)); 5746 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5747 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5748 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5749 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5750 return SCTP_DISPOSITION_ABORT; 5751 } 5752 5753 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5754 * the ASCONF chunk was sent by doubling the RTO timer value. 5755 * This is done in SCTP_CMD_STRIKE. 5756 */ 5757 5758 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5759 * choose an alternate destination address (please refer to RFC2960 5760 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5761 * chunk, it MUST be the same (including its serial number) as the last 5762 * ASCONF sent. 5763 */ 5764 sctp_chunk_hold(asoc->addip_last_asconf); 5765 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5766 SCTP_CHUNK(asoc->addip_last_asconf)); 5767 5768 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5769 * destination is selected, then the RTO used will be that of the new 5770 * destination address. 5771 */ 5772 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5773 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5774 5775 return SCTP_DISPOSITION_CONSUME; 5776 } 5777 5778 /* sctpimpguide-05 Section 2.12.2 5779 * The sender of the SHUTDOWN MAY also start an overall guard timer 5780 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5781 * At the expiration of this timer the sender SHOULD abort the association 5782 * by sending an ABORT chunk. 5783 */ 5784 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5785 const struct sctp_endpoint *ep, 5786 const struct sctp_association *asoc, 5787 const sctp_subtype_t type, 5788 void *arg, 5789 sctp_cmd_seq_t *commands) 5790 { 5791 struct sctp_chunk *reply = NULL; 5792 5793 pr_debug("%s: timer T5 expired\n", __func__); 5794 5795 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5796 5797 reply = sctp_make_abort(asoc, NULL, 0); 5798 if (!reply) 5799 goto nomem; 5800 5801 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5802 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5803 SCTP_ERROR(ETIMEDOUT)); 5804 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5805 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5806 5807 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5808 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5809 5810 return SCTP_DISPOSITION_DELETE_TCB; 5811 nomem: 5812 return SCTP_DISPOSITION_NOMEM; 5813 } 5814 5815 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5816 * the association is automatically closed by starting the shutdown process. 5817 * The work that needs to be done is same as when SHUTDOWN is initiated by 5818 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5819 */ 5820 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5821 struct net *net, 5822 const struct sctp_endpoint *ep, 5823 const struct sctp_association *asoc, 5824 const sctp_subtype_t type, 5825 void *arg, 5826 sctp_cmd_seq_t *commands) 5827 { 5828 int disposition; 5829 5830 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5831 5832 /* From 9.2 Shutdown of an Association 5833 * Upon receipt of the SHUTDOWN primitive from its upper 5834 * layer, the endpoint enters SHUTDOWN-PENDING state and 5835 * remains there until all outstanding data has been 5836 * acknowledged by its peer. The endpoint accepts no new data 5837 * from its upper layer, but retransmits data to the far end 5838 * if necessary to fill gaps. 5839 */ 5840 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5841 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5842 5843 disposition = SCTP_DISPOSITION_CONSUME; 5844 if (sctp_outq_is_empty(&asoc->outqueue)) { 5845 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5846 arg, commands); 5847 } 5848 return disposition; 5849 } 5850 5851 /***************************************************************************** 5852 * These are sa state functions which could apply to all types of events. 5853 ****************************************************************************/ 5854 5855 /* 5856 * This table entry is not implemented. 5857 * 5858 * Inputs 5859 * (endpoint, asoc, chunk) 5860 * 5861 * The return value is the disposition of the chunk. 5862 */ 5863 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5864 const struct sctp_endpoint *ep, 5865 const struct sctp_association *asoc, 5866 const sctp_subtype_t type, 5867 void *arg, 5868 sctp_cmd_seq_t *commands) 5869 { 5870 return SCTP_DISPOSITION_NOT_IMPL; 5871 } 5872 5873 /* 5874 * This table entry represents a bug. 5875 * 5876 * Inputs 5877 * (endpoint, asoc, chunk) 5878 * 5879 * The return value is the disposition of the chunk. 5880 */ 5881 sctp_disposition_t sctp_sf_bug(struct net *net, 5882 const struct sctp_endpoint *ep, 5883 const struct sctp_association *asoc, 5884 const sctp_subtype_t type, 5885 void *arg, 5886 sctp_cmd_seq_t *commands) 5887 { 5888 return SCTP_DISPOSITION_BUG; 5889 } 5890 5891 /* 5892 * This table entry represents the firing of a timer in the wrong state. 5893 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5894 * when the association is in the wrong state. This event should 5895 * be ignored, so as to prevent any rearming of the timer. 5896 * 5897 * Inputs 5898 * (endpoint, asoc, chunk) 5899 * 5900 * The return value is the disposition of the chunk. 5901 */ 5902 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5903 const struct sctp_endpoint *ep, 5904 const struct sctp_association *asoc, 5905 const sctp_subtype_t type, 5906 void *arg, 5907 sctp_cmd_seq_t *commands) 5908 { 5909 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 5910 5911 return SCTP_DISPOSITION_CONSUME; 5912 } 5913 5914 /******************************************************************** 5915 * 2nd Level Abstractions 5916 ********************************************************************/ 5917 5918 /* Pull the SACK chunk based on the SACK header. */ 5919 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5920 { 5921 struct sctp_sackhdr *sack; 5922 unsigned int len; 5923 __u16 num_blocks; 5924 __u16 num_dup_tsns; 5925 5926 /* Protect ourselves from reading too far into 5927 * the skb from a bogus sender. 5928 */ 5929 sack = (struct sctp_sackhdr *) chunk->skb->data; 5930 5931 num_blocks = ntohs(sack->num_gap_ack_blocks); 5932 num_dup_tsns = ntohs(sack->num_dup_tsns); 5933 len = sizeof(struct sctp_sackhdr); 5934 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5935 if (len > chunk->skb->len) 5936 return NULL; 5937 5938 skb_pull(chunk->skb, len); 5939 5940 return sack; 5941 } 5942 5943 /* Create an ABORT packet to be sent as a response, with the specified 5944 * error causes. 5945 */ 5946 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 5947 const struct sctp_endpoint *ep, 5948 const struct sctp_association *asoc, 5949 struct sctp_chunk *chunk, 5950 const void *payload, 5951 size_t paylen) 5952 { 5953 struct sctp_packet *packet; 5954 struct sctp_chunk *abort; 5955 5956 packet = sctp_ootb_pkt_new(net, asoc, chunk); 5957 5958 if (packet) { 5959 /* Make an ABORT. 5960 * The T bit will be set if the asoc is NULL. 5961 */ 5962 abort = sctp_make_abort(asoc, chunk, paylen); 5963 if (!abort) { 5964 sctp_ootb_pkt_free(packet); 5965 return NULL; 5966 } 5967 5968 /* Reflect vtag if T-Bit is set */ 5969 if (sctp_test_T_bit(abort)) 5970 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5971 5972 /* Add specified error causes, i.e., payload, to the 5973 * end of the chunk. 5974 */ 5975 sctp_addto_chunk(abort, paylen, payload); 5976 5977 /* Set the skb to the belonging sock for accounting. */ 5978 abort->skb->sk = ep->base.sk; 5979 5980 sctp_packet_append_chunk(packet, abort); 5981 5982 } 5983 5984 return packet; 5985 } 5986 5987 /* Allocate a packet for responding in the OOTB conditions. */ 5988 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 5989 const struct sctp_association *asoc, 5990 const struct sctp_chunk *chunk) 5991 { 5992 struct sctp_packet *packet; 5993 struct sctp_transport *transport; 5994 __u16 sport; 5995 __u16 dport; 5996 __u32 vtag; 5997 5998 /* Get the source and destination port from the inbound packet. */ 5999 sport = ntohs(chunk->sctp_hdr->dest); 6000 dport = ntohs(chunk->sctp_hdr->source); 6001 6002 /* The V-tag is going to be the same as the inbound packet if no 6003 * association exists, otherwise, use the peer's vtag. 6004 */ 6005 if (asoc) { 6006 /* Special case the INIT-ACK as there is no peer's vtag 6007 * yet. 6008 */ 6009 switch (chunk->chunk_hdr->type) { 6010 case SCTP_CID_INIT_ACK: 6011 { 6012 sctp_initack_chunk_t *initack; 6013 6014 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6015 vtag = ntohl(initack->init_hdr.init_tag); 6016 break; 6017 } 6018 default: 6019 vtag = asoc->peer.i.init_tag; 6020 break; 6021 } 6022 } else { 6023 /* Special case the INIT and stale COOKIE_ECHO as there is no 6024 * vtag yet. 6025 */ 6026 switch (chunk->chunk_hdr->type) { 6027 case SCTP_CID_INIT: 6028 { 6029 sctp_init_chunk_t *init; 6030 6031 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6032 vtag = ntohl(init->init_hdr.init_tag); 6033 break; 6034 } 6035 default: 6036 vtag = ntohl(chunk->sctp_hdr->vtag); 6037 break; 6038 } 6039 } 6040 6041 /* Make a transport for the bucket, Eliza... */ 6042 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6043 if (!transport) 6044 goto nomem; 6045 6046 /* Cache a route for the transport with the chunk's destination as 6047 * the source address. 6048 */ 6049 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6050 sctp_sk(net->sctp.ctl_sock)); 6051 6052 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 6053 packet = sctp_packet_config(packet, vtag, 0); 6054 6055 return packet; 6056 6057 nomem: 6058 return NULL; 6059 } 6060 6061 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6062 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6063 { 6064 sctp_transport_free(packet->transport); 6065 } 6066 6067 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6068 static void sctp_send_stale_cookie_err(struct net *net, 6069 const struct sctp_endpoint *ep, 6070 const struct sctp_association *asoc, 6071 const struct sctp_chunk *chunk, 6072 sctp_cmd_seq_t *commands, 6073 struct sctp_chunk *err_chunk) 6074 { 6075 struct sctp_packet *packet; 6076 6077 if (err_chunk) { 6078 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6079 if (packet) { 6080 struct sctp_signed_cookie *cookie; 6081 6082 /* Override the OOTB vtag from the cookie. */ 6083 cookie = chunk->subh.cookie_hdr; 6084 packet->vtag = cookie->c.peer_vtag; 6085 6086 /* Set the skb to the belonging sock for accounting. */ 6087 err_chunk->skb->sk = ep->base.sk; 6088 sctp_packet_append_chunk(packet, err_chunk); 6089 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6090 SCTP_PACKET(packet)); 6091 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6092 } else 6093 sctp_chunk_free (err_chunk); 6094 } 6095 } 6096 6097 6098 /* Process a data chunk */ 6099 static int sctp_eat_data(const struct sctp_association *asoc, 6100 struct sctp_chunk *chunk, 6101 sctp_cmd_seq_t *commands) 6102 { 6103 sctp_datahdr_t *data_hdr; 6104 struct sctp_chunk *err; 6105 size_t datalen; 6106 sctp_verb_t deliver; 6107 int tmp; 6108 __u32 tsn; 6109 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6110 struct sock *sk = asoc->base.sk; 6111 struct net *net = sock_net(sk); 6112 u16 ssn; 6113 u16 sid; 6114 u8 ordered = 0; 6115 6116 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6117 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6118 6119 tsn = ntohl(data_hdr->tsn); 6120 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6121 6122 /* ASSERT: Now skb->data is really the user data. */ 6123 6124 /* Process ECN based congestion. 6125 * 6126 * Since the chunk structure is reused for all chunks within 6127 * a packet, we use ecn_ce_done to track if we've already 6128 * done CE processing for this packet. 6129 * 6130 * We need to do ECN processing even if we plan to discard the 6131 * chunk later. 6132 */ 6133 6134 if (!chunk->ecn_ce_done) { 6135 struct sctp_af *af; 6136 chunk->ecn_ce_done = 1; 6137 6138 af = sctp_get_af_specific( 6139 ipver2af(ip_hdr(chunk->skb)->version)); 6140 6141 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 6142 /* Do real work as sideffect. */ 6143 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6144 SCTP_U32(tsn)); 6145 } 6146 } 6147 6148 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6149 if (tmp < 0) { 6150 /* The TSN is too high--silently discard the chunk and 6151 * count on it getting retransmitted later. 6152 */ 6153 if (chunk->asoc) 6154 chunk->asoc->stats.outofseqtsns++; 6155 return SCTP_IERROR_HIGH_TSN; 6156 } else if (tmp > 0) { 6157 /* This is a duplicate. Record it. */ 6158 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6159 return SCTP_IERROR_DUP_TSN; 6160 } 6161 6162 /* This is a new TSN. */ 6163 6164 /* Discard if there is no room in the receive window. 6165 * Actually, allow a little bit of overflow (up to a MTU). 6166 */ 6167 datalen = ntohs(chunk->chunk_hdr->length); 6168 datalen -= sizeof(sctp_data_chunk_t); 6169 6170 deliver = SCTP_CMD_CHUNK_ULP; 6171 6172 /* Think about partial delivery. */ 6173 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6174 6175 /* Even if we don't accept this chunk there is 6176 * memory pressure. 6177 */ 6178 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6179 } 6180 6181 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6182 * seems a bit troublesome in that frag_point varies based on 6183 * PMTU. In cases, such as loopback, this might be a rather 6184 * large spill over. 6185 */ 6186 if ((!chunk->data_accepted) && (!asoc->rwnd || 6187 (datalen > asoc->rwnd + asoc->frag_point))) { 6188 6189 /* If this is the next TSN, consider reneging to make 6190 * room. Note: Playing nice with a confused sender. A 6191 * malicious sender can still eat up all our buffer 6192 * space and in the future we may want to detect and 6193 * do more drastic reneging. 6194 */ 6195 if (sctp_tsnmap_has_gap(map) && 6196 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6197 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6198 deliver = SCTP_CMD_RENEGE; 6199 } else { 6200 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6201 __func__, tsn, datalen, asoc->rwnd); 6202 6203 return SCTP_IERROR_IGNORE_TSN; 6204 } 6205 } 6206 6207 /* 6208 * Also try to renege to limit our memory usage in the event that 6209 * we are under memory pressure 6210 * If we can't renege, don't worry about it, the sk_rmem_schedule 6211 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6212 * memory usage too much 6213 */ 6214 if (*sk->sk_prot_creator->memory_pressure) { 6215 if (sctp_tsnmap_has_gap(map) && 6216 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6217 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6218 __func__, tsn); 6219 deliver = SCTP_CMD_RENEGE; 6220 } 6221 } 6222 6223 /* 6224 * Section 3.3.10.9 No User Data (9) 6225 * 6226 * Cause of error 6227 * --------------- 6228 * No User Data: This error cause is returned to the originator of a 6229 * DATA chunk if a received DATA chunk has no user data. 6230 */ 6231 if (unlikely(0 == datalen)) { 6232 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6233 if (err) { 6234 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6235 SCTP_CHUNK(err)); 6236 } 6237 /* We are going to ABORT, so we might as well stop 6238 * processing the rest of the chunks in the packet. 6239 */ 6240 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6241 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6242 SCTP_ERROR(ECONNABORTED)); 6243 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6244 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6245 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6246 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6247 return SCTP_IERROR_NO_DATA; 6248 } 6249 6250 chunk->data_accepted = 1; 6251 6252 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6253 * if we renege and the chunk arrives again. 6254 */ 6255 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6256 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6257 if (chunk->asoc) 6258 chunk->asoc->stats.iuodchunks++; 6259 } else { 6260 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6261 if (chunk->asoc) 6262 chunk->asoc->stats.iodchunks++; 6263 ordered = 1; 6264 } 6265 6266 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6267 * 6268 * If an endpoint receive a DATA chunk with an invalid stream 6269 * identifier, it shall acknowledge the reception of the DATA chunk 6270 * following the normal procedure, immediately send an ERROR chunk 6271 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6272 * and discard the DATA chunk. 6273 */ 6274 sid = ntohs(data_hdr->stream); 6275 if (sid >= asoc->c.sinit_max_instreams) { 6276 /* Mark tsn as received even though we drop it */ 6277 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6278 6279 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6280 &data_hdr->stream, 6281 sizeof(data_hdr->stream), 6282 sizeof(u16)); 6283 if (err) 6284 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6285 SCTP_CHUNK(err)); 6286 return SCTP_IERROR_BAD_STREAM; 6287 } 6288 6289 /* Check to see if the SSN is possible for this TSN. 6290 * The biggest gap we can record is 4K wide. Since SSNs wrap 6291 * at an unsigned short, there is no way that an SSN can 6292 * wrap and for a valid TSN. We can simply check if the current 6293 * SSN is smaller then the next expected one. If it is, it wrapped 6294 * and is invalid. 6295 */ 6296 ssn = ntohs(data_hdr->ssn); 6297 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6298 return SCTP_IERROR_PROTO_VIOLATION; 6299 } 6300 6301 /* Send the data up to the user. Note: Schedule the 6302 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6303 * chunk needs the updated rwnd. 6304 */ 6305 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6306 6307 return SCTP_IERROR_NO_ERROR; 6308 } 6309