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, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <lksctp-developers@lists.sourceforge.net> 32 * 33 * Or submit a bug report through the following website: 34 * http://www.sf.net/projects/lksctp 35 * 36 * Written or modified by: 37 * La Monte H.P. Yarroll <piggy@acm.org> 38 * Karl Knutson <karl@athena.chicago.il.us> 39 * Mathew Kotowsky <kotowsky@sctp.org> 40 * Sridhar Samudrala <samudrala@us.ibm.com> 41 * Jon Grimm <jgrimm@us.ibm.com> 42 * Hui Huang <hui.huang@nokia.com> 43 * Dajiang Zhang <dajiang.zhang@nokia.com> 44 * Daisy Chang <daisyc@us.ibm.com> 45 * Ardelle Fan <ardelle.fan@intel.com> 46 * Ryan Layer <rmlayer@us.ibm.com> 47 * Kevin Gao <kevin.gao@intel.com> 48 * 49 * Any bugs reported given to us we will try to fix... any fixes shared will 50 * be incorporated into the next SCTP release. 51 */ 52 53 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 54 55 #include <linux/types.h> 56 #include <linux/kernel.h> 57 #include <linux/ip.h> 58 #include <linux/ipv6.h> 59 #include <linux/net.h> 60 #include <linux/inet.h> 61 #include <linux/slab.h> 62 #include <net/sock.h> 63 #include <net/inet_ecn.h> 64 #include <linux/skbuff.h> 65 #include <net/sctp/sctp.h> 66 #include <net/sctp/sm.h> 67 #include <net/sctp/structs.h> 68 69 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 70 const struct sctp_endpoint *ep, 71 const struct sctp_association *asoc, 72 struct sctp_chunk *chunk, 73 const void *payload, 74 size_t paylen); 75 static int sctp_eat_data(const struct sctp_association *asoc, 76 struct sctp_chunk *chunk, 77 sctp_cmd_seq_t *commands); 78 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 79 const struct sctp_association *asoc, 80 const struct sctp_chunk *chunk); 81 static void sctp_send_stale_cookie_err(struct net *net, 82 const struct sctp_endpoint *ep, 83 const struct sctp_association *asoc, 84 const struct sctp_chunk *chunk, 85 sctp_cmd_seq_t *commands, 86 struct sctp_chunk *err_chunk); 87 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 88 const struct sctp_endpoint *ep, 89 const struct sctp_association *asoc, 90 const sctp_subtype_t type, 91 void *arg, 92 sctp_cmd_seq_t *commands); 93 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 94 const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const sctp_subtype_t type, 97 void *arg, 98 sctp_cmd_seq_t *commands); 99 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 100 const struct sctp_endpoint *ep, 101 const struct sctp_association *asoc, 102 const sctp_subtype_t type, 103 void *arg, 104 sctp_cmd_seq_t *commands); 105 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 106 107 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 108 sctp_cmd_seq_t *commands, 109 __be16 error, int sk_err, 110 const struct sctp_association *asoc, 111 struct sctp_transport *transport); 112 113 static sctp_disposition_t sctp_sf_abort_violation( 114 struct net *net, 115 const struct sctp_endpoint *ep, 116 const struct sctp_association *asoc, 117 void *arg, 118 sctp_cmd_seq_t *commands, 119 const __u8 *payload, 120 const size_t paylen); 121 122 static sctp_disposition_t sctp_sf_violation_chunklen( 123 struct net *net, 124 const struct sctp_endpoint *ep, 125 const struct sctp_association *asoc, 126 const sctp_subtype_t type, 127 void *arg, 128 sctp_cmd_seq_t *commands); 129 130 static sctp_disposition_t sctp_sf_violation_paramlen( 131 struct net *net, 132 const struct sctp_endpoint *ep, 133 const struct sctp_association *asoc, 134 const sctp_subtype_t type, 135 void *arg, void *ext, 136 sctp_cmd_seq_t *commands); 137 138 static sctp_disposition_t sctp_sf_violation_ctsn( 139 struct net *net, 140 const struct sctp_endpoint *ep, 141 const struct sctp_association *asoc, 142 const sctp_subtype_t type, 143 void *arg, 144 sctp_cmd_seq_t *commands); 145 146 static sctp_disposition_t sctp_sf_violation_chunk( 147 struct net *net, 148 const struct sctp_endpoint *ep, 149 const struct sctp_association *asoc, 150 const sctp_subtype_t type, 151 void *arg, 152 sctp_cmd_seq_t *commands); 153 154 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 155 const struct sctp_endpoint *ep, 156 const struct sctp_association *asoc, 157 const sctp_subtype_t type, 158 struct sctp_chunk *chunk); 159 160 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 161 const struct sctp_endpoint *ep, 162 const struct sctp_association *asoc, 163 const sctp_subtype_t type, 164 void *arg, 165 sctp_cmd_seq_t *commands); 166 167 /* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: 1 = Valid length 171 * 0 = Invalid length 172 * 173 */ 174 static inline int 175 sctp_chunk_length_valid(struct sctp_chunk *chunk, 176 __u16 required_length) 177 { 178 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 179 180 if (unlikely(chunk_length < required_length)) 181 return 0; 182 183 return 1; 184 } 185 186 /********************************************************** 187 * These are the state functions for handling chunk events. 188 **********************************************************/ 189 190 /* 191 * Process the final SHUTDOWN COMPLETE. 192 * 193 * Section: 4 (C) (diagram), 9.2 194 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 195 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 196 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 197 * should stop the T2-shutdown timer and remove all knowledge of the 198 * association (and thus the association enters the CLOSED state). 199 * 200 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 201 * C) Rules for packet carrying SHUTDOWN COMPLETE: 202 * ... 203 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 204 * if the Verification Tag field of the packet matches its own tag and 205 * the T bit is not set 206 * OR 207 * it is set to its peer's tag and the T bit is set in the Chunk 208 * Flags. 209 * Otherwise, the receiver MUST silently discard the packet 210 * and take no further action. An endpoint MUST ignore the 211 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 212 * 213 * Inputs 214 * (endpoint, asoc, chunk) 215 * 216 * Outputs 217 * (asoc, reply_msg, msg_up, timers, counters) 218 * 219 * The return value is the disposition of the chunk. 220 */ 221 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 222 const struct sctp_endpoint *ep, 223 const struct sctp_association *asoc, 224 const sctp_subtype_t type, 225 void *arg, 226 sctp_cmd_seq_t *commands) 227 { 228 struct sctp_chunk *chunk = arg; 229 struct sctp_ulpevent *ev; 230 231 if (!sctp_vtag_verify_either(chunk, asoc)) 232 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 233 234 /* RFC 2960 6.10 Bundling 235 * 236 * An endpoint MUST NOT bundle INIT, INIT ACK or 237 * SHUTDOWN COMPLETE with any other chunks. 238 */ 239 if (!chunk->singleton) 240 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 241 242 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 243 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 244 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 245 commands); 246 247 /* RFC 2960 10.2 SCTP-to-ULP 248 * 249 * H) SHUTDOWN COMPLETE notification 250 * 251 * When SCTP completes the shutdown procedures (section 9.2) this 252 * notification is passed to the upper layer. 253 */ 254 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 255 0, 0, 0, NULL, GFP_ATOMIC); 256 if (ev) 257 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 258 SCTP_ULPEVENT(ev)); 259 260 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 261 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 262 * not the chunk should be discarded. If the endpoint is in 263 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 264 * T2-shutdown timer and remove all knowledge of the 265 * association (and thus the association enters the CLOSED 266 * state). 267 */ 268 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 269 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 270 271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 272 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 273 274 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 275 SCTP_STATE(SCTP_STATE_CLOSED)); 276 277 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 278 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 279 280 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 281 282 return SCTP_DISPOSITION_DELETE_TCB; 283 } 284 285 /* 286 * Respond to a normal INIT chunk. 287 * We are the side that is being asked for an association. 288 * 289 * Section: 5.1 Normal Establishment of an Association, B 290 * B) "Z" shall respond immediately with an INIT ACK chunk. The 291 * destination IP address of the INIT ACK MUST be set to the source 292 * IP address of the INIT to which this INIT ACK is responding. In 293 * the response, besides filling in other parameters, "Z" must set the 294 * Verification Tag field to Tag_A, and also provide its own 295 * Verification Tag (Tag_Z) in the Initiate Tag field. 296 * 297 * Verification Tag: Must be 0. 298 * 299 * Inputs 300 * (endpoint, asoc, chunk) 301 * 302 * Outputs 303 * (asoc, reply_msg, msg_up, timers, counters) 304 * 305 * The return value is the disposition of the chunk. 306 */ 307 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 308 const struct sctp_endpoint *ep, 309 const struct sctp_association *asoc, 310 const sctp_subtype_t type, 311 void *arg, 312 sctp_cmd_seq_t *commands) 313 { 314 struct sctp_chunk *chunk = arg; 315 struct sctp_chunk *repl; 316 struct sctp_association *new_asoc; 317 struct sctp_chunk *err_chunk; 318 struct sctp_packet *packet; 319 sctp_unrecognized_param_t *unk_param; 320 int len; 321 322 /* 6.10 Bundling 323 * An endpoint MUST NOT bundle INIT, INIT ACK or 324 * SHUTDOWN COMPLETE with any other chunks. 325 * 326 * IG Section 2.11.2 327 * Furthermore, we require that the receiver of an INIT chunk MUST 328 * enforce these rules by silently discarding an arriving packet 329 * with an INIT chunk that is bundled with other chunks. 330 */ 331 if (!chunk->singleton) 332 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 333 334 /* If the packet is an OOTB packet which is temporarily on the 335 * control endpoint, respond with an ABORT. 336 */ 337 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 338 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 339 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 340 } 341 342 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 343 * Tag. 344 */ 345 if (chunk->sctp_hdr->vtag != 0) 346 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 347 348 /* Make sure that the INIT chunk has a valid length. 349 * Normally, this would cause an ABORT with a Protocol Violation 350 * error, but since we don't have an association, we'll 351 * just discard the packet. 352 */ 353 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 354 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 355 356 /* If the INIT is coming toward a closing socket, we'll send back 357 * and ABORT. Essentially, this catches the race of INIT being 358 * backloged to the socket at the same time as the user isses close(). 359 * Since the socket and all its associations are going away, we 360 * can treat this OOTB 361 */ 362 if (sctp_sstate(ep->base.sk, CLOSING)) 363 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 364 365 /* Verify the INIT chunk before processing it. */ 366 err_chunk = NULL; 367 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 368 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 369 &err_chunk)) { 370 /* This chunk contains fatal error. It is to be discarded. 371 * Send an ABORT, with causes if there is any. 372 */ 373 if (err_chunk) { 374 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 375 (__u8 *)(err_chunk->chunk_hdr) + 376 sizeof(sctp_chunkhdr_t), 377 ntohs(err_chunk->chunk_hdr->length) - 378 sizeof(sctp_chunkhdr_t)); 379 380 sctp_chunk_free(err_chunk); 381 382 if (packet) { 383 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 384 SCTP_PACKET(packet)); 385 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 386 return SCTP_DISPOSITION_CONSUME; 387 } else { 388 return SCTP_DISPOSITION_NOMEM; 389 } 390 } else { 391 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 392 commands); 393 } 394 } 395 396 /* Grab the INIT header. */ 397 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 398 399 /* Tag the variable length parameters. */ 400 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 401 402 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 403 if (!new_asoc) 404 goto nomem; 405 406 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 407 sctp_scope(sctp_source(chunk)), 408 GFP_ATOMIC) < 0) 409 goto nomem_init; 410 411 /* The call, sctp_process_init(), can fail on memory allocation. */ 412 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 413 (sctp_init_chunk_t *)chunk->chunk_hdr, 414 GFP_ATOMIC)) 415 goto nomem_init; 416 417 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 418 419 /* If there are errors need to be reported for unknown parameters, 420 * make sure to reserve enough room in the INIT ACK for them. 421 */ 422 len = 0; 423 if (err_chunk) 424 len = ntohs(err_chunk->chunk_hdr->length) - 425 sizeof(sctp_chunkhdr_t); 426 427 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 428 if (!repl) 429 goto nomem_init; 430 431 /* If there are errors need to be reported for unknown parameters, 432 * include them in the outgoing INIT ACK as "Unrecognized parameter" 433 * parameter. 434 */ 435 if (err_chunk) { 436 /* Get the "Unrecognized parameter" parameter(s) out of the 437 * ERROR chunk generated by sctp_verify_init(). Since the 438 * error cause code for "unknown parameter" and the 439 * "Unrecognized parameter" type is the same, we can 440 * construct the parameters in INIT ACK by copying the 441 * ERROR causes over. 442 */ 443 unk_param = (sctp_unrecognized_param_t *) 444 ((__u8 *)(err_chunk->chunk_hdr) + 445 sizeof(sctp_chunkhdr_t)); 446 /* Replace the cause code with the "Unrecognized parameter" 447 * parameter type. 448 */ 449 sctp_addto_chunk(repl, len, unk_param); 450 sctp_chunk_free(err_chunk); 451 } 452 453 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 454 455 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 456 457 /* 458 * Note: After sending out INIT ACK with the State Cookie parameter, 459 * "Z" MUST NOT allocate any resources, nor keep any states for the 460 * new association. Otherwise, "Z" will be vulnerable to resource 461 * attacks. 462 */ 463 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 464 465 return SCTP_DISPOSITION_DELETE_TCB; 466 467 nomem_init: 468 sctp_association_free(new_asoc); 469 nomem: 470 if (err_chunk) 471 sctp_chunk_free(err_chunk); 472 return SCTP_DISPOSITION_NOMEM; 473 } 474 475 /* 476 * Respond to a normal INIT ACK chunk. 477 * We are the side that is initiating the association. 478 * 479 * Section: 5.1 Normal Establishment of an Association, C 480 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 481 * timer and leave COOKIE-WAIT state. "A" shall then send the State 482 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 483 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 484 * 485 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 486 * DATA chunks, but it MUST be the first chunk in the packet and 487 * until the COOKIE ACK is returned the sender MUST NOT send any 488 * other packets to the peer. 489 * 490 * Verification Tag: 3.3.3 491 * If the value of the Initiate Tag in a received INIT ACK chunk is 492 * found to be 0, the receiver MUST treat it as an error and close the 493 * association by transmitting an ABORT. 494 * 495 * Inputs 496 * (endpoint, asoc, chunk) 497 * 498 * Outputs 499 * (asoc, reply_msg, msg_up, timers, counters) 500 * 501 * The return value is the disposition of the chunk. 502 */ 503 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 504 const struct sctp_endpoint *ep, 505 const struct sctp_association *asoc, 506 const sctp_subtype_t type, 507 void *arg, 508 sctp_cmd_seq_t *commands) 509 { 510 struct sctp_chunk *chunk = arg; 511 sctp_init_chunk_t *initchunk; 512 struct sctp_chunk *err_chunk; 513 struct sctp_packet *packet; 514 515 if (!sctp_vtag_verify(chunk, asoc)) 516 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 517 518 /* 6.10 Bundling 519 * An endpoint MUST NOT bundle INIT, INIT ACK or 520 * SHUTDOWN COMPLETE with any other chunks. 521 */ 522 if (!chunk->singleton) 523 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 524 525 /* Make sure that the INIT-ACK chunk has a valid length */ 526 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 527 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 528 commands); 529 /* Grab the INIT header. */ 530 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 531 532 /* Verify the INIT chunk before processing it. */ 533 err_chunk = NULL; 534 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 535 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 536 &err_chunk)) { 537 538 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 539 540 /* This chunk contains fatal error. It is to be discarded. 541 * Send an ABORT, with causes. If there are no causes, 542 * then there wasn't enough memory. Just terminate 543 * the association. 544 */ 545 if (err_chunk) { 546 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 547 (__u8 *)(err_chunk->chunk_hdr) + 548 sizeof(sctp_chunkhdr_t), 549 ntohs(err_chunk->chunk_hdr->length) - 550 sizeof(sctp_chunkhdr_t)); 551 552 sctp_chunk_free(err_chunk); 553 554 if (packet) { 555 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 556 SCTP_PACKET(packet)); 557 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 558 error = SCTP_ERROR_INV_PARAM; 559 } 560 } 561 562 /* SCTP-AUTH, Section 6.3: 563 * It should be noted that if the receiver wants to tear 564 * down an association in an authenticated way only, the 565 * handling of malformed packets should not result in 566 * tearing down the association. 567 * 568 * This means that if we only want to abort associations 569 * in an authenticated way (i.e AUTH+ABORT), then we 570 * can't destroy this association just because the packet 571 * was malformed. 572 */ 573 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 574 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 575 576 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 577 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 578 asoc, chunk->transport); 579 } 580 581 /* Tag the variable length parameters. Note that we never 582 * convert the parameters in an INIT chunk. 583 */ 584 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 585 586 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 587 588 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 589 SCTP_PEER_INIT(initchunk)); 590 591 /* Reset init error count upon receipt of INIT-ACK. */ 592 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 593 594 /* 5.1 C) "A" shall stop the T1-init timer and leave 595 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 596 * timer, and enter the COOKIE-ECHOED state. 597 */ 598 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 599 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 600 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 601 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 602 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 603 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 604 605 /* SCTP-AUTH: genereate the assocition shared keys so that 606 * we can potentially signe the COOKIE-ECHO. 607 */ 608 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 609 610 /* 5.1 C) "A" shall then send the State Cookie received in the 611 * INIT ACK chunk in a COOKIE ECHO chunk, ... 612 */ 613 /* If there is any errors to report, send the ERROR chunk generated 614 * for unknown parameters as well. 615 */ 616 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 617 SCTP_CHUNK(err_chunk)); 618 619 return SCTP_DISPOSITION_CONSUME; 620 } 621 622 /* 623 * Respond to a normal COOKIE ECHO chunk. 624 * We are the side that is being asked for an association. 625 * 626 * Section: 5.1 Normal Establishment of an Association, D 627 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 628 * with a COOKIE ACK chunk after building a TCB and moving to 629 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 630 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 631 * chunk MUST be the first chunk in the packet. 632 * 633 * IMPLEMENTATION NOTE: An implementation may choose to send the 634 * Communication Up notification to the SCTP user upon reception 635 * of a valid COOKIE ECHO chunk. 636 * 637 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 638 * D) Rules for packet carrying a COOKIE ECHO 639 * 640 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 641 * Initial Tag received in the INIT ACK. 642 * 643 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 644 * 645 * Inputs 646 * (endpoint, asoc, chunk) 647 * 648 * Outputs 649 * (asoc, reply_msg, msg_up, timers, counters) 650 * 651 * The return value is the disposition of the chunk. 652 */ 653 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 654 const struct sctp_endpoint *ep, 655 const struct sctp_association *asoc, 656 const sctp_subtype_t type, void *arg, 657 sctp_cmd_seq_t *commands) 658 { 659 struct sctp_chunk *chunk = arg; 660 struct sctp_association *new_asoc; 661 sctp_init_chunk_t *peer_init; 662 struct sctp_chunk *repl; 663 struct sctp_ulpevent *ev, *ai_ev = NULL; 664 int error = 0; 665 struct sctp_chunk *err_chk_p; 666 struct sock *sk; 667 668 /* If the packet is an OOTB packet which is temporarily on the 669 * control endpoint, respond with an ABORT. 670 */ 671 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 672 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 673 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 674 } 675 676 /* Make sure that the COOKIE_ECHO chunk has a valid length. 677 * In this case, we check that we have enough for at least a 678 * chunk header. More detailed verification is done 679 * in sctp_unpack_cookie(). 680 */ 681 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 682 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 683 684 /* If the endpoint is not listening or if the number of associations 685 * on the TCP-style socket exceed the max backlog, respond with an 686 * ABORT. 687 */ 688 sk = ep->base.sk; 689 if (!sctp_sstate(sk, LISTENING) || 690 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 691 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 692 693 /* "Decode" the chunk. We have no optional parameters so we 694 * are in good shape. 695 */ 696 chunk->subh.cookie_hdr = 697 (struct sctp_signed_cookie *)chunk->skb->data; 698 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 699 sizeof(sctp_chunkhdr_t))) 700 goto nomem; 701 702 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 703 * "Z" will reply with a COOKIE ACK chunk after building a TCB 704 * and moving to the ESTABLISHED state. 705 */ 706 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 707 &err_chk_p); 708 709 /* FIXME: 710 * If the re-build failed, what is the proper error path 711 * from here? 712 * 713 * [We should abort the association. --piggy] 714 */ 715 if (!new_asoc) { 716 /* FIXME: Several errors are possible. A bad cookie should 717 * be silently discarded, but think about logging it too. 718 */ 719 switch (error) { 720 case -SCTP_IERROR_NOMEM: 721 goto nomem; 722 723 case -SCTP_IERROR_STALE_COOKIE: 724 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 725 err_chk_p); 726 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 727 728 case -SCTP_IERROR_BAD_SIG: 729 default: 730 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 731 } 732 } 733 734 735 /* Delay state machine commands until later. 736 * 737 * Re-build the bind address for the association is done in 738 * the sctp_unpack_cookie() already. 739 */ 740 /* This is a brand-new association, so these are not yet side 741 * effects--it is safe to run them here. 742 */ 743 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 744 745 if (!sctp_process_init(new_asoc, chunk, 746 &chunk->subh.cookie_hdr->c.peer_addr, 747 peer_init, GFP_ATOMIC)) 748 goto nomem_init; 749 750 /* SCTP-AUTH: Now that we've populate required fields in 751 * sctp_process_init, set up the assocaition shared keys as 752 * necessary so that we can potentially authenticate the ACK 753 */ 754 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 755 if (error) 756 goto nomem_init; 757 758 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 759 * is supposed to be authenticated and we have to do delayed 760 * authentication. We've just recreated the association using 761 * the information in the cookie and now it's much easier to 762 * do the authentication. 763 */ 764 if (chunk->auth_chunk) { 765 struct sctp_chunk auth; 766 sctp_ierror_t ret; 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->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->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 struct sctp_chunk *chunk = arg; 1059 struct sctp_chunk *reply; 1060 size_t paylen = 0; 1061 1062 if (!sctp_vtag_verify(chunk, asoc)) 1063 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1064 1065 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1066 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1067 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1068 commands); 1069 1070 /* 8.3 The receiver of the HEARTBEAT should immediately 1071 * respond with a HEARTBEAT ACK that contains the Heartbeat 1072 * Information field copied from the received HEARTBEAT chunk. 1073 */ 1074 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1075 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1076 if (!pskb_pull(chunk->skb, paylen)) 1077 goto nomem; 1078 1079 reply = sctp_make_heartbeat_ack(asoc, chunk, 1080 chunk->subh.hb_hdr, paylen); 1081 if (!reply) 1082 goto nomem; 1083 1084 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1085 return SCTP_DISPOSITION_CONSUME; 1086 1087 nomem: 1088 return SCTP_DISPOSITION_NOMEM; 1089 } 1090 1091 /* 1092 * Process the returning HEARTBEAT ACK. 1093 * 1094 * Section: 8.3 Path Heartbeat 1095 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1096 * should clear the error counter of the destination transport 1097 * address to which the HEARTBEAT was sent, and mark the destination 1098 * transport address as active if it is not so marked. The endpoint may 1099 * optionally report to the upper layer when an inactive destination 1100 * address is marked as active due to the reception of the latest 1101 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1102 * clear the association overall error count as well (as defined 1103 * in section 8.1). 1104 * 1105 * The receiver of the HEARTBEAT ACK should also perform an RTT 1106 * measurement for that destination transport address using the time 1107 * value carried in the HEARTBEAT ACK chunk. 1108 * 1109 * Verification Tag: 8.5 Verification Tag [Normal verification] 1110 * 1111 * Inputs 1112 * (endpoint, asoc, chunk) 1113 * 1114 * Outputs 1115 * (asoc, reply_msg, msg_up, timers, counters) 1116 * 1117 * The return value is the disposition of the chunk. 1118 */ 1119 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1120 const struct sctp_endpoint *ep, 1121 const struct sctp_association *asoc, 1122 const sctp_subtype_t type, 1123 void *arg, 1124 sctp_cmd_seq_t *commands) 1125 { 1126 struct sctp_chunk *chunk = arg; 1127 union sctp_addr from_addr; 1128 struct sctp_transport *link; 1129 sctp_sender_hb_info_t *hbinfo; 1130 unsigned long max_interval; 1131 1132 if (!sctp_vtag_verify(chunk, asoc)) 1133 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1134 1135 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1136 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1137 sizeof(sctp_sender_hb_info_t))) 1138 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1139 commands); 1140 1141 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1142 /* Make sure that the length of the parameter is what we expect */ 1143 if (ntohs(hbinfo->param_hdr.length) != 1144 sizeof(sctp_sender_hb_info_t)) { 1145 return SCTP_DISPOSITION_DISCARD; 1146 } 1147 1148 from_addr = hbinfo->daddr; 1149 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1150 1151 /* This should never happen, but lets log it if so. */ 1152 if (unlikely(!link)) { 1153 if (from_addr.sa.sa_family == AF_INET6) { 1154 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1155 __func__, 1156 asoc, 1157 &from_addr.v6.sin6_addr); 1158 } else { 1159 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1160 __func__, 1161 asoc, 1162 &from_addr.v4.sin_addr.s_addr); 1163 } 1164 return SCTP_DISPOSITION_DISCARD; 1165 } 1166 1167 /* Validate the 64-bit random nonce. */ 1168 if (hbinfo->hb_nonce != link->hb_nonce) 1169 return SCTP_DISPOSITION_DISCARD; 1170 1171 max_interval = link->hbinterval + link->rto; 1172 1173 /* Check if the timestamp looks valid. */ 1174 if (time_after(hbinfo->sent_at, jiffies) || 1175 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1176 SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp " 1177 "received for transport: %p\n", 1178 __func__, link); 1179 return SCTP_DISPOSITION_DISCARD; 1180 } 1181 1182 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1183 * the HEARTBEAT should clear the error counter of the 1184 * destination transport address to which the HEARTBEAT was 1185 * sent and mark the destination transport address as active if 1186 * it is not so marked. 1187 */ 1188 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1189 1190 return SCTP_DISPOSITION_CONSUME; 1191 } 1192 1193 /* Helper function to send out an abort for the restart 1194 * condition. 1195 */ 1196 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1197 struct sctp_chunk *init, 1198 sctp_cmd_seq_t *commands) 1199 { 1200 int len; 1201 struct sctp_packet *pkt; 1202 union sctp_addr_param *addrparm; 1203 struct sctp_errhdr *errhdr; 1204 struct sctp_endpoint *ep; 1205 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1206 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1207 1208 /* Build the error on the stack. We are way to malloc crazy 1209 * throughout the code today. 1210 */ 1211 errhdr = (struct sctp_errhdr *)buffer; 1212 addrparm = (union sctp_addr_param *)errhdr->variable; 1213 1214 /* Copy into a parm format. */ 1215 len = af->to_addr_param(ssa, addrparm); 1216 len += sizeof(sctp_errhdr_t); 1217 1218 errhdr->cause = SCTP_ERROR_RESTART; 1219 errhdr->length = htons(len); 1220 1221 /* Assign to the control socket. */ 1222 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1223 1224 /* Association is NULL since this may be a restart attack and we 1225 * want to send back the attacker's vtag. 1226 */ 1227 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1228 1229 if (!pkt) 1230 goto out; 1231 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1232 1233 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1234 1235 /* Discard the rest of the inbound packet. */ 1236 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1237 1238 out: 1239 /* Even if there is no memory, treat as a failure so 1240 * the packet will get dropped. 1241 */ 1242 return 0; 1243 } 1244 1245 static bool list_has_sctp_addr(const struct list_head *list, 1246 union sctp_addr *ipaddr) 1247 { 1248 struct sctp_transport *addr; 1249 1250 list_for_each_entry(addr, list, transports) { 1251 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1252 return true; 1253 } 1254 1255 return false; 1256 } 1257 /* A restart is occurring, check to make sure no new addresses 1258 * are being added as we may be under a takeover attack. 1259 */ 1260 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1261 const struct sctp_association *asoc, 1262 struct sctp_chunk *init, 1263 sctp_cmd_seq_t *commands) 1264 { 1265 struct net *net = sock_net(new_asoc->base.sk); 1266 struct sctp_transport *new_addr; 1267 int ret = 1; 1268 1269 /* Implementor's Guide - Section 5.2.2 1270 * ... 1271 * Before responding the endpoint MUST check to see if the 1272 * unexpected INIT adds new addresses to the association. If new 1273 * addresses are added to the association, the endpoint MUST respond 1274 * with an ABORT.. 1275 */ 1276 1277 /* Search through all current addresses and make sure 1278 * we aren't adding any new ones. 1279 */ 1280 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1281 transports) { 1282 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1283 &new_addr->ipaddr)) { 1284 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1285 commands); 1286 ret = 0; 1287 break; 1288 } 1289 } 1290 1291 /* Return success if all addresses were found. */ 1292 return ret; 1293 } 1294 1295 /* Populate the verification/tie tags based on overlapping INIT 1296 * scenario. 1297 * 1298 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1299 */ 1300 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1301 const struct sctp_association *asoc) 1302 { 1303 switch (asoc->state) { 1304 1305 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1306 1307 case SCTP_STATE_COOKIE_WAIT: 1308 new_asoc->c.my_vtag = asoc->c.my_vtag; 1309 new_asoc->c.my_ttag = asoc->c.my_vtag; 1310 new_asoc->c.peer_ttag = 0; 1311 break; 1312 1313 case SCTP_STATE_COOKIE_ECHOED: 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 = asoc->c.peer_vtag; 1317 break; 1318 1319 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1320 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1321 */ 1322 default: 1323 new_asoc->c.my_ttag = asoc->c.my_vtag; 1324 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1325 break; 1326 } 1327 1328 /* Other parameters for the endpoint SHOULD be copied from the 1329 * existing parameters of the association (e.g. number of 1330 * outbound streams) into the INIT ACK and cookie. 1331 */ 1332 new_asoc->rwnd = asoc->rwnd; 1333 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1334 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1335 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1336 } 1337 1338 /* 1339 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1340 * handling action. 1341 * 1342 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1343 * 1344 * Returns value representing action to be taken. These action values 1345 * correspond to Action/Description values in RFC 2960, Table 2. 1346 */ 1347 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1348 const struct sctp_association *asoc) 1349 { 1350 /* In this case, the peer may have restarted. */ 1351 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1352 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1353 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1354 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1355 return 'A'; 1356 1357 /* Collision case B. */ 1358 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1359 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1360 (0 == asoc->c.peer_vtag))) { 1361 return 'B'; 1362 } 1363 1364 /* Collision case D. */ 1365 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1366 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1367 return 'D'; 1368 1369 /* Collision case C. */ 1370 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1371 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1372 (0 == new_asoc->c.my_ttag) && 1373 (0 == new_asoc->c.peer_ttag)) 1374 return 'C'; 1375 1376 /* No match to any of the special cases; discard this packet. */ 1377 return 'E'; 1378 } 1379 1380 /* Common helper routine for both duplicate and simulataneous INIT 1381 * chunk handling. 1382 */ 1383 static sctp_disposition_t sctp_sf_do_unexpected_init( 1384 struct net *net, 1385 const struct sctp_endpoint *ep, 1386 const struct sctp_association *asoc, 1387 const sctp_subtype_t type, 1388 void *arg, sctp_cmd_seq_t *commands) 1389 { 1390 sctp_disposition_t retval; 1391 struct sctp_chunk *chunk = arg; 1392 struct sctp_chunk *repl; 1393 struct sctp_association *new_asoc; 1394 struct sctp_chunk *err_chunk; 1395 struct sctp_packet *packet; 1396 sctp_unrecognized_param_t *unk_param; 1397 int len; 1398 1399 /* 6.10 Bundling 1400 * An endpoint MUST NOT bundle INIT, INIT ACK or 1401 * SHUTDOWN COMPLETE with any other chunks. 1402 * 1403 * IG Section 2.11.2 1404 * Furthermore, we require that the receiver of an INIT chunk MUST 1405 * enforce these rules by silently discarding an arriving packet 1406 * with an INIT chunk that is bundled with other chunks. 1407 */ 1408 if (!chunk->singleton) 1409 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1410 1411 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1412 * Tag. 1413 */ 1414 if (chunk->sctp_hdr->vtag != 0) 1415 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1416 1417 /* Make sure that the INIT chunk has a valid length. 1418 * In this case, we generate a protocol violation since we have 1419 * an association established. 1420 */ 1421 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1422 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1423 commands); 1424 /* Grab the INIT header. */ 1425 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1426 1427 /* Tag the variable length parameters. */ 1428 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1429 1430 /* Verify the INIT chunk before processing it. */ 1431 err_chunk = NULL; 1432 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 1433 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1434 &err_chunk)) { 1435 /* This chunk contains fatal error. It is to be discarded. 1436 * Send an ABORT, with causes if there is any. 1437 */ 1438 if (err_chunk) { 1439 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1440 (__u8 *)(err_chunk->chunk_hdr) + 1441 sizeof(sctp_chunkhdr_t), 1442 ntohs(err_chunk->chunk_hdr->length) - 1443 sizeof(sctp_chunkhdr_t)); 1444 1445 if (packet) { 1446 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1447 SCTP_PACKET(packet)); 1448 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1449 retval = SCTP_DISPOSITION_CONSUME; 1450 } else { 1451 retval = SCTP_DISPOSITION_NOMEM; 1452 } 1453 goto cleanup; 1454 } else { 1455 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1456 commands); 1457 } 1458 } 1459 1460 /* 1461 * Other parameters for the endpoint SHOULD be copied from the 1462 * existing parameters of the association (e.g. number of 1463 * outbound streams) into the INIT ACK and cookie. 1464 * FIXME: We are copying parameters from the endpoint not the 1465 * association. 1466 */ 1467 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1468 if (!new_asoc) 1469 goto nomem; 1470 1471 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1472 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1473 goto nomem; 1474 1475 /* In the outbound INIT ACK the endpoint MUST copy its current 1476 * Verification Tag and Peers Verification tag into a reserved 1477 * place (local tie-tag and per tie-tag) within the state cookie. 1478 */ 1479 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1480 (sctp_init_chunk_t *)chunk->chunk_hdr, 1481 GFP_ATOMIC)) 1482 goto nomem; 1483 1484 /* Make sure no new addresses are being added during the 1485 * restart. Do not do this check for COOKIE-WAIT state, 1486 * since there are no peer addresses to check against. 1487 * Upon return an ABORT will have been sent if needed. 1488 */ 1489 if (!sctp_state(asoc, COOKIE_WAIT)) { 1490 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1491 commands)) { 1492 retval = SCTP_DISPOSITION_CONSUME; 1493 goto nomem_retval; 1494 } 1495 } 1496 1497 sctp_tietags_populate(new_asoc, asoc); 1498 1499 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1500 1501 /* If there are errors need to be reported for unknown parameters, 1502 * make sure to reserve enough room in the INIT ACK for them. 1503 */ 1504 len = 0; 1505 if (err_chunk) { 1506 len = ntohs(err_chunk->chunk_hdr->length) - 1507 sizeof(sctp_chunkhdr_t); 1508 } 1509 1510 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1511 if (!repl) 1512 goto nomem; 1513 1514 /* If there are errors need to be reported for unknown parameters, 1515 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1516 * parameter. 1517 */ 1518 if (err_chunk) { 1519 /* Get the "Unrecognized parameter" parameter(s) out of the 1520 * ERROR chunk generated by sctp_verify_init(). Since the 1521 * error cause code for "unknown parameter" and the 1522 * "Unrecognized parameter" type is the same, we can 1523 * construct the parameters in INIT ACK by copying the 1524 * ERROR causes over. 1525 */ 1526 unk_param = (sctp_unrecognized_param_t *) 1527 ((__u8 *)(err_chunk->chunk_hdr) + 1528 sizeof(sctp_chunkhdr_t)); 1529 /* Replace the cause code with the "Unrecognized parameter" 1530 * parameter type. 1531 */ 1532 sctp_addto_chunk(repl, len, unk_param); 1533 } 1534 1535 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1536 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1537 1538 /* 1539 * Note: After sending out INIT ACK with the State Cookie parameter, 1540 * "Z" MUST NOT allocate any resources for this new association. 1541 * Otherwise, "Z" will be vulnerable to resource attacks. 1542 */ 1543 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1544 retval = SCTP_DISPOSITION_CONSUME; 1545 1546 return retval; 1547 1548 nomem: 1549 retval = SCTP_DISPOSITION_NOMEM; 1550 nomem_retval: 1551 if (new_asoc) 1552 sctp_association_free(new_asoc); 1553 cleanup: 1554 if (err_chunk) 1555 sctp_chunk_free(err_chunk); 1556 return retval; 1557 } 1558 1559 /* 1560 * Handle simultaneous INIT. 1561 * This means we started an INIT and then we got an INIT request from 1562 * our peer. 1563 * 1564 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1565 * This usually indicates an initialization collision, i.e., each 1566 * endpoint is attempting, at about the same time, to establish an 1567 * association with the other endpoint. 1568 * 1569 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1570 * endpoint MUST respond with an INIT ACK using the same parameters it 1571 * sent in its original INIT chunk (including its Verification Tag, 1572 * unchanged). These original parameters are combined with those from the 1573 * newly received INIT chunk. The endpoint shall also generate a State 1574 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1575 * INIT to calculate the State Cookie. 1576 * 1577 * After that, the endpoint MUST NOT change its state, the T1-init 1578 * timer shall be left running and the corresponding TCB MUST NOT be 1579 * destroyed. The normal procedures for handling State Cookies when 1580 * a TCB exists will resolve the duplicate INITs to a single association. 1581 * 1582 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1583 * its Tie-Tags with the Tag information of itself and its peer (see 1584 * section 5.2.2 for a description of the Tie-Tags). 1585 * 1586 * Verification Tag: Not explicit, but an INIT can not have a valid 1587 * verification tag, so we skip the check. 1588 * 1589 * Inputs 1590 * (endpoint, asoc, chunk) 1591 * 1592 * Outputs 1593 * (asoc, reply_msg, msg_up, timers, counters) 1594 * 1595 * The return value is the disposition of the chunk. 1596 */ 1597 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1598 const struct sctp_endpoint *ep, 1599 const struct sctp_association *asoc, 1600 const sctp_subtype_t type, 1601 void *arg, 1602 sctp_cmd_seq_t *commands) 1603 { 1604 /* Call helper to do the real work for both simulataneous and 1605 * duplicate INIT chunk handling. 1606 */ 1607 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1608 } 1609 1610 /* 1611 * Handle duplicated INIT messages. These are usually delayed 1612 * restransmissions. 1613 * 1614 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1615 * COOKIE-ECHOED and COOKIE-WAIT 1616 * 1617 * Unless otherwise stated, upon reception of an unexpected INIT for 1618 * this association, the endpoint shall generate an INIT ACK with a 1619 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1620 * current Verification Tag and peer's Verification Tag into a reserved 1621 * place within the state cookie. We shall refer to these locations as 1622 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1623 * containing this INIT ACK MUST carry a Verification Tag value equal to 1624 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1625 * MUST contain a new Initiation Tag (randomly generated see Section 1626 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1627 * existing parameters of the association (e.g. number of outbound 1628 * streams) into the INIT ACK and cookie. 1629 * 1630 * After sending out the INIT ACK, the endpoint shall take no further 1631 * actions, i.e., the existing association, including its current state, 1632 * and the corresponding TCB MUST NOT be changed. 1633 * 1634 * Note: Only when a TCB exists and the association is not in a COOKIE- 1635 * WAIT state are the Tie-Tags populated. For a normal association INIT 1636 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1637 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1638 * State Cookie are populated as specified in section 5.2.1. 1639 * 1640 * Verification Tag: Not specified, but an INIT has no way of knowing 1641 * what the verification tag could be, so we ignore it. 1642 * 1643 * Inputs 1644 * (endpoint, asoc, chunk) 1645 * 1646 * Outputs 1647 * (asoc, reply_msg, msg_up, timers, counters) 1648 * 1649 * The return value is the disposition of the chunk. 1650 */ 1651 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1652 const struct sctp_endpoint *ep, 1653 const struct sctp_association *asoc, 1654 const sctp_subtype_t type, 1655 void *arg, 1656 sctp_cmd_seq_t *commands) 1657 { 1658 /* Call helper to do the real work for both simulataneous and 1659 * duplicate INIT chunk handling. 1660 */ 1661 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1662 } 1663 1664 1665 /* 1666 * Unexpected INIT-ACK handler. 1667 * 1668 * Section 5.2.3 1669 * If an INIT ACK received by an endpoint in any state other than the 1670 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1671 * An unexpected INIT ACK usually indicates the processing of an old or 1672 * duplicated INIT chunk. 1673 */ 1674 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1675 const struct sctp_endpoint *ep, 1676 const struct sctp_association *asoc, 1677 const sctp_subtype_t type, 1678 void *arg, sctp_cmd_seq_t *commands) 1679 { 1680 /* Per the above section, we'll discard the chunk if we have an 1681 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1682 */ 1683 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1684 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1685 else 1686 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1687 } 1688 1689 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1690 * 1691 * Section 5.2.4 1692 * A) In this case, the peer may have restarted. 1693 */ 1694 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1695 const struct sctp_endpoint *ep, 1696 const struct sctp_association *asoc, 1697 struct sctp_chunk *chunk, 1698 sctp_cmd_seq_t *commands, 1699 struct sctp_association *new_asoc) 1700 { 1701 sctp_init_chunk_t *peer_init; 1702 struct sctp_ulpevent *ev; 1703 struct sctp_chunk *repl; 1704 struct sctp_chunk *err; 1705 sctp_disposition_t disposition; 1706 1707 /* new_asoc is a brand-new association, so these are not yet 1708 * side effects--it is safe to run them here. 1709 */ 1710 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1711 1712 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1713 GFP_ATOMIC)) 1714 goto nomem; 1715 1716 /* Make sure no new addresses are being added during the 1717 * restart. Though this is a pretty complicated attack 1718 * since you'd have to get inside the cookie. 1719 */ 1720 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1721 return SCTP_DISPOSITION_CONSUME; 1722 } 1723 1724 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1725 * the peer has restarted (Action A), it MUST NOT setup a new 1726 * association but instead resend the SHUTDOWN ACK and send an ERROR 1727 * chunk with a "Cookie Received while Shutting Down" error cause to 1728 * its peer. 1729 */ 1730 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1731 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1732 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1733 chunk, commands); 1734 if (SCTP_DISPOSITION_NOMEM == disposition) 1735 goto nomem; 1736 1737 err = sctp_make_op_error(asoc, chunk, 1738 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1739 NULL, 0, 0); 1740 if (err) 1741 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1742 SCTP_CHUNK(err)); 1743 1744 return SCTP_DISPOSITION_CONSUME; 1745 } 1746 1747 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1748 * data. Consider the optional choice of resending of this data. 1749 */ 1750 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1751 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1752 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1753 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1754 1755 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1756 * and ASCONF-ACK cache. 1757 */ 1758 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1759 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1760 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1761 1762 repl = sctp_make_cookie_ack(new_asoc, chunk); 1763 if (!repl) 1764 goto nomem; 1765 1766 /* Report association restart to upper layer. */ 1767 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1768 new_asoc->c.sinit_num_ostreams, 1769 new_asoc->c.sinit_max_instreams, 1770 NULL, GFP_ATOMIC); 1771 if (!ev) 1772 goto nomem_ev; 1773 1774 /* Update the content of current association. */ 1775 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1776 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1777 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1778 return SCTP_DISPOSITION_CONSUME; 1779 1780 nomem_ev: 1781 sctp_chunk_free(repl); 1782 nomem: 1783 return SCTP_DISPOSITION_NOMEM; 1784 } 1785 1786 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1787 * 1788 * Section 5.2.4 1789 * B) In this case, both sides may be attempting to start an association 1790 * at about the same time but the peer endpoint started its INIT 1791 * after responding to the local endpoint's INIT 1792 */ 1793 /* This case represents an initialization collision. */ 1794 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1795 const struct sctp_endpoint *ep, 1796 const struct sctp_association *asoc, 1797 struct sctp_chunk *chunk, 1798 sctp_cmd_seq_t *commands, 1799 struct sctp_association *new_asoc) 1800 { 1801 sctp_init_chunk_t *peer_init; 1802 struct sctp_chunk *repl; 1803 1804 /* new_asoc is a brand-new association, so these are not yet 1805 * side effects--it is safe to run them here. 1806 */ 1807 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1808 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1809 GFP_ATOMIC)) 1810 goto nomem; 1811 1812 /* Update the content of current association. */ 1813 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1814 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1815 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1816 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1817 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1818 1819 repl = sctp_make_cookie_ack(new_asoc, chunk); 1820 if (!repl) 1821 goto nomem; 1822 1823 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1824 1825 /* RFC 2960 5.1 Normal Establishment of an Association 1826 * 1827 * D) IMPLEMENTATION NOTE: An implementation may choose to 1828 * send the Communication Up notification to the SCTP user 1829 * upon reception of a valid COOKIE ECHO chunk. 1830 * 1831 * Sadly, this needs to be implemented as a side-effect, because 1832 * we are not guaranteed to have set the association id of the real 1833 * association and so these notifications need to be delayed until 1834 * the association id is allocated. 1835 */ 1836 1837 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1838 1839 /* Sockets API Draft Section 5.3.1.6 1840 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1841 * delivers this notification to inform the application that of the 1842 * peers requested adaptation layer. 1843 * 1844 * This also needs to be done as a side effect for the same reason as 1845 * above. 1846 */ 1847 if (asoc->peer.adaptation_ind) 1848 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1849 1850 return SCTP_DISPOSITION_CONSUME; 1851 1852 nomem: 1853 return SCTP_DISPOSITION_NOMEM; 1854 } 1855 1856 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1857 * 1858 * Section 5.2.4 1859 * C) In this case, the local endpoint's cookie has arrived late. 1860 * Before it arrived, the local endpoint sent an INIT and received an 1861 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1862 * but a new tag of its own. 1863 */ 1864 /* This case represents an initialization collision. */ 1865 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1866 const struct sctp_endpoint *ep, 1867 const struct sctp_association *asoc, 1868 struct sctp_chunk *chunk, 1869 sctp_cmd_seq_t *commands, 1870 struct sctp_association *new_asoc) 1871 { 1872 /* The cookie should be silently discarded. 1873 * The endpoint SHOULD NOT change states and should leave 1874 * any timers running. 1875 */ 1876 return SCTP_DISPOSITION_DISCARD; 1877 } 1878 1879 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1880 * 1881 * Section 5.2.4 1882 * 1883 * D) When both local and remote tags match the endpoint should always 1884 * enter the ESTABLISHED state, if it has not already done so. 1885 */ 1886 /* This case represents an initialization collision. */ 1887 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1888 const struct sctp_endpoint *ep, 1889 const struct sctp_association *asoc, 1890 struct sctp_chunk *chunk, 1891 sctp_cmd_seq_t *commands, 1892 struct sctp_association *new_asoc) 1893 { 1894 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1895 struct sctp_chunk *repl; 1896 1897 /* Clarification from Implementor's Guide: 1898 * D) When both local and remote tags match the endpoint should 1899 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1900 * It should stop any cookie timer that may be running and send 1901 * a COOKIE ACK. 1902 */ 1903 1904 /* Don't accidentally move back into established state. */ 1905 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1906 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1907 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1908 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1909 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1910 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1911 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1912 SCTP_NULL()); 1913 1914 /* RFC 2960 5.1 Normal Establishment of an Association 1915 * 1916 * D) IMPLEMENTATION NOTE: An implementation may choose 1917 * to send the Communication Up notification to the 1918 * SCTP user upon reception of a valid COOKIE 1919 * ECHO chunk. 1920 */ 1921 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1922 SCTP_COMM_UP, 0, 1923 asoc->c.sinit_num_ostreams, 1924 asoc->c.sinit_max_instreams, 1925 NULL, GFP_ATOMIC); 1926 if (!ev) 1927 goto nomem; 1928 1929 /* Sockets API Draft Section 5.3.1.6 1930 * When a peer sends a Adaptation Layer Indication parameter, 1931 * SCTP delivers this notification to inform the application 1932 * that of the peers requested adaptation layer. 1933 */ 1934 if (asoc->peer.adaptation_ind) { 1935 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1936 GFP_ATOMIC); 1937 if (!ai_ev) 1938 goto nomem; 1939 1940 } 1941 } 1942 1943 repl = sctp_make_cookie_ack(new_asoc, chunk); 1944 if (!repl) 1945 goto nomem; 1946 1947 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1948 1949 if (ev) 1950 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1951 SCTP_ULPEVENT(ev)); 1952 if (ai_ev) 1953 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1954 SCTP_ULPEVENT(ai_ev)); 1955 1956 return SCTP_DISPOSITION_CONSUME; 1957 1958 nomem: 1959 if (ai_ev) 1960 sctp_ulpevent_free(ai_ev); 1961 if (ev) 1962 sctp_ulpevent_free(ev); 1963 return SCTP_DISPOSITION_NOMEM; 1964 } 1965 1966 /* 1967 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1968 * chunk was retransmitted and then delayed in the network. 1969 * 1970 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1971 * 1972 * Verification Tag: None. Do cookie validation. 1973 * 1974 * Inputs 1975 * (endpoint, asoc, chunk) 1976 * 1977 * Outputs 1978 * (asoc, reply_msg, msg_up, timers, counters) 1979 * 1980 * The return value is the disposition of the chunk. 1981 */ 1982 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 1983 const struct sctp_endpoint *ep, 1984 const struct sctp_association *asoc, 1985 const sctp_subtype_t type, 1986 void *arg, 1987 sctp_cmd_seq_t *commands) 1988 { 1989 sctp_disposition_t retval; 1990 struct sctp_chunk *chunk = arg; 1991 struct sctp_association *new_asoc; 1992 int error = 0; 1993 char action; 1994 struct sctp_chunk *err_chk_p; 1995 1996 /* Make sure that the chunk has a valid length from the protocol 1997 * perspective. In this case check to make sure we have at least 1998 * enough for the chunk header. Cookie length verification is 1999 * done later. 2000 */ 2001 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2002 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2003 commands); 2004 2005 /* "Decode" the chunk. We have no optional parameters so we 2006 * are in good shape. 2007 */ 2008 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2009 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2010 sizeof(sctp_chunkhdr_t))) 2011 goto nomem; 2012 2013 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2014 * of a duplicate COOKIE ECHO match the Verification Tags of the 2015 * current association, consider the State Cookie valid even if 2016 * the lifespan is exceeded. 2017 */ 2018 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2019 &err_chk_p); 2020 2021 /* FIXME: 2022 * If the re-build failed, what is the proper error path 2023 * from here? 2024 * 2025 * [We should abort the association. --piggy] 2026 */ 2027 if (!new_asoc) { 2028 /* FIXME: Several errors are possible. A bad cookie should 2029 * be silently discarded, but think about logging it too. 2030 */ 2031 switch (error) { 2032 case -SCTP_IERROR_NOMEM: 2033 goto nomem; 2034 2035 case -SCTP_IERROR_STALE_COOKIE: 2036 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2037 err_chk_p); 2038 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2039 case -SCTP_IERROR_BAD_SIG: 2040 default: 2041 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2042 } 2043 } 2044 2045 /* Compare the tie_tag in cookie with the verification tag of 2046 * current association. 2047 */ 2048 action = sctp_tietags_compare(new_asoc, asoc); 2049 2050 switch (action) { 2051 case 'A': /* Association restart. */ 2052 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2053 new_asoc); 2054 break; 2055 2056 case 'B': /* Collision case B. */ 2057 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2058 new_asoc); 2059 break; 2060 2061 case 'C': /* Collision case C. */ 2062 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2063 new_asoc); 2064 break; 2065 2066 case 'D': /* Collision case D. */ 2067 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2068 new_asoc); 2069 break; 2070 2071 default: /* Discard packet for all others. */ 2072 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2073 break; 2074 } 2075 2076 /* Delete the tempory new association. */ 2077 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 2078 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2079 2080 /* Restore association pointer to provide SCTP command interpeter 2081 * with a valid context in case it needs to manipulate 2082 * the queues */ 2083 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2084 SCTP_ASOC((struct sctp_association *)asoc)); 2085 2086 return retval; 2087 2088 nomem: 2089 return SCTP_DISPOSITION_NOMEM; 2090 } 2091 2092 /* 2093 * Process an ABORT. (SHUTDOWN-PENDING state) 2094 * 2095 * See sctp_sf_do_9_1_abort(). 2096 */ 2097 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2098 struct net *net, 2099 const struct sctp_endpoint *ep, 2100 const struct sctp_association *asoc, 2101 const sctp_subtype_t type, 2102 void *arg, 2103 sctp_cmd_seq_t *commands) 2104 { 2105 struct sctp_chunk *chunk = arg; 2106 2107 if (!sctp_vtag_verify_either(chunk, asoc)) 2108 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2109 2110 /* Make sure that the ABORT chunk has a valid length. 2111 * Since this is an ABORT chunk, we have to discard it 2112 * because of the following text: 2113 * RFC 2960, Section 3.3.7 2114 * If an endpoint receives an ABORT with a format error or for an 2115 * association that doesn't exist, it MUST silently discard it. 2116 * Because the length is "invalid", we can't really discard just 2117 * as we do not know its true length. So, to be safe, discard the 2118 * packet. 2119 */ 2120 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2121 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2122 2123 /* ADD-IP: Special case for ABORT chunks 2124 * F4) One special consideration is that ABORT Chunks arriving 2125 * destined to the IP address being deleted MUST be 2126 * ignored (see Section 5.3.1 for further details). 2127 */ 2128 if (SCTP_ADDR_DEL == 2129 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2130 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2131 2132 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2133 } 2134 2135 /* 2136 * Process an ABORT. (SHUTDOWN-SENT state) 2137 * 2138 * See sctp_sf_do_9_1_abort(). 2139 */ 2140 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2141 const struct sctp_endpoint *ep, 2142 const struct sctp_association *asoc, 2143 const sctp_subtype_t type, 2144 void *arg, 2145 sctp_cmd_seq_t *commands) 2146 { 2147 struct sctp_chunk *chunk = arg; 2148 2149 if (!sctp_vtag_verify_either(chunk, asoc)) 2150 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2151 2152 /* Make sure that the ABORT chunk has a valid length. 2153 * Since this is an ABORT chunk, we have to discard it 2154 * because of the following text: 2155 * RFC 2960, Section 3.3.7 2156 * If an endpoint receives an ABORT with a format error or for an 2157 * association that doesn't exist, it MUST silently discard it. 2158 * Because the length is "invalid", we can't really discard just 2159 * as we do not know its true length. So, to be safe, discard the 2160 * packet. 2161 */ 2162 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2163 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2164 2165 /* ADD-IP: Special case for ABORT chunks 2166 * F4) One special consideration is that ABORT Chunks arriving 2167 * destined to the IP address being deleted MUST be 2168 * ignored (see Section 5.3.1 for further details). 2169 */ 2170 if (SCTP_ADDR_DEL == 2171 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2172 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2173 2174 /* Stop the T2-shutdown timer. */ 2175 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2176 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2177 2178 /* Stop the T5-shutdown guard timer. */ 2179 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2180 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2181 2182 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2183 } 2184 2185 /* 2186 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2187 * 2188 * See sctp_sf_do_9_1_abort(). 2189 */ 2190 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2191 struct net *net, 2192 const struct sctp_endpoint *ep, 2193 const struct sctp_association *asoc, 2194 const sctp_subtype_t type, 2195 void *arg, 2196 sctp_cmd_seq_t *commands) 2197 { 2198 /* The same T2 timer, so we should be able to use 2199 * common function with the SHUTDOWN-SENT state. 2200 */ 2201 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2202 } 2203 2204 /* 2205 * Handle an Error received in COOKIE_ECHOED state. 2206 * 2207 * Only handle the error type of stale COOKIE Error, the other errors will 2208 * be ignored. 2209 * 2210 * Inputs 2211 * (endpoint, asoc, chunk) 2212 * 2213 * Outputs 2214 * (asoc, reply_msg, msg_up, timers, counters) 2215 * 2216 * The return value is the disposition of the chunk. 2217 */ 2218 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2219 const struct sctp_endpoint *ep, 2220 const struct sctp_association *asoc, 2221 const sctp_subtype_t type, 2222 void *arg, 2223 sctp_cmd_seq_t *commands) 2224 { 2225 struct sctp_chunk *chunk = arg; 2226 sctp_errhdr_t *err; 2227 2228 if (!sctp_vtag_verify(chunk, asoc)) 2229 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2230 2231 /* Make sure that the ERROR chunk has a valid length. 2232 * The parameter walking depends on this as well. 2233 */ 2234 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2235 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2236 commands); 2237 2238 /* Process the error here */ 2239 /* FUTURE FIXME: When PR-SCTP related and other optional 2240 * parms are emitted, this will have to change to handle multiple 2241 * errors. 2242 */ 2243 sctp_walk_errors(err, chunk->chunk_hdr) { 2244 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2245 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2246 arg, commands); 2247 } 2248 2249 /* It is possible to have malformed error causes, and that 2250 * will cause us to end the walk early. However, since 2251 * we are discarding the packet, there should be no adverse 2252 * affects. 2253 */ 2254 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2255 } 2256 2257 /* 2258 * Handle a Stale COOKIE Error 2259 * 2260 * Section: 5.2.6 Handle Stale COOKIE Error 2261 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2262 * one of the following three alternatives. 2263 * ... 2264 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2265 * Preservative parameter requesting an extension to the lifetime of 2266 * the State Cookie. When calculating the time extension, an 2267 * implementation SHOULD use the RTT information measured based on the 2268 * previous COOKIE ECHO / ERROR exchange, and should add no more 2269 * than 1 second beyond the measured RTT, due to long State Cookie 2270 * lifetimes making the endpoint more subject to a replay attack. 2271 * 2272 * Verification Tag: Not explicit, but safe to ignore. 2273 * 2274 * Inputs 2275 * (endpoint, asoc, chunk) 2276 * 2277 * Outputs 2278 * (asoc, reply_msg, msg_up, timers, counters) 2279 * 2280 * The return value is the disposition of the chunk. 2281 */ 2282 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2283 const struct sctp_endpoint *ep, 2284 const struct sctp_association *asoc, 2285 const sctp_subtype_t type, 2286 void *arg, 2287 sctp_cmd_seq_t *commands) 2288 { 2289 struct sctp_chunk *chunk = arg; 2290 time_t stale; 2291 sctp_cookie_preserve_param_t bht; 2292 sctp_errhdr_t *err; 2293 struct sctp_chunk *reply; 2294 struct sctp_bind_addr *bp; 2295 int attempts = asoc->init_err_counter + 1; 2296 2297 if (attempts > asoc->max_init_attempts) { 2298 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2299 SCTP_ERROR(ETIMEDOUT)); 2300 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2301 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2302 return SCTP_DISPOSITION_DELETE_TCB; 2303 } 2304 2305 err = (sctp_errhdr_t *)(chunk->skb->data); 2306 2307 /* When calculating the time extension, an implementation 2308 * SHOULD use the RTT information measured based on the 2309 * previous COOKIE ECHO / ERROR exchange, and should add no 2310 * more than 1 second beyond the measured RTT, due to long 2311 * State Cookie lifetimes making the endpoint more subject to 2312 * a replay attack. 2313 * Measure of Staleness's unit is usec. (1/1000000 sec) 2314 * Suggested Cookie Life-span Increment's unit is msec. 2315 * (1/1000 sec) 2316 * In general, if you use the suggested cookie life, the value 2317 * found in the field of measure of staleness should be doubled 2318 * to give ample time to retransmit the new cookie and thus 2319 * yield a higher probability of success on the reattempt. 2320 */ 2321 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2322 stale = (stale * 2) / 1000; 2323 2324 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2325 bht.param_hdr.length = htons(sizeof(bht)); 2326 bht.lifespan_increment = htonl(stale); 2327 2328 /* Build that new INIT chunk. */ 2329 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2330 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2331 if (!reply) 2332 goto nomem; 2333 2334 sctp_addto_chunk(reply, sizeof(bht), &bht); 2335 2336 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2337 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2338 2339 /* Stop pending T3-rtx and heartbeat timers */ 2340 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2341 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2342 2343 /* Delete non-primary peer ip addresses since we are transitioning 2344 * back to the COOKIE-WAIT state 2345 */ 2346 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2347 2348 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2349 * resend 2350 */ 2351 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2352 SCTP_TRANSPORT(asoc->peer.primary_path)); 2353 2354 /* Cast away the const modifier, as we want to just 2355 * rerun it through as a sideffect. 2356 */ 2357 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2358 2359 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2360 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2361 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2362 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2363 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2364 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2365 2366 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2367 2368 return SCTP_DISPOSITION_CONSUME; 2369 2370 nomem: 2371 return SCTP_DISPOSITION_NOMEM; 2372 } 2373 2374 /* 2375 * Process an ABORT. 2376 * 2377 * Section: 9.1 2378 * After checking the Verification Tag, the receiving endpoint shall 2379 * remove the association from its record, and shall report the 2380 * termination to its upper layer. 2381 * 2382 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2383 * B) Rules for packet carrying ABORT: 2384 * 2385 * - The endpoint shall always fill in the Verification Tag field of the 2386 * outbound packet with the destination endpoint's tag value if it 2387 * is known. 2388 * 2389 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2390 * MUST follow the procedure described in Section 8.4. 2391 * 2392 * - The receiver MUST accept the packet if the Verification Tag 2393 * matches either its own tag, OR the tag of its peer. Otherwise, the 2394 * receiver MUST silently discard the packet and take no further 2395 * action. 2396 * 2397 * Inputs 2398 * (endpoint, asoc, chunk) 2399 * 2400 * Outputs 2401 * (asoc, reply_msg, msg_up, timers, counters) 2402 * 2403 * The return value is the disposition of the chunk. 2404 */ 2405 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2406 const struct sctp_endpoint *ep, 2407 const struct sctp_association *asoc, 2408 const sctp_subtype_t type, 2409 void *arg, 2410 sctp_cmd_seq_t *commands) 2411 { 2412 struct sctp_chunk *chunk = arg; 2413 2414 if (!sctp_vtag_verify_either(chunk, asoc)) 2415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2416 2417 /* Make sure that the ABORT chunk has a valid length. 2418 * Since this is an ABORT chunk, we have to discard it 2419 * because of the following text: 2420 * RFC 2960, Section 3.3.7 2421 * If an endpoint receives an ABORT with a format error or for an 2422 * association that doesn't exist, it MUST silently discard it. 2423 * Because the length is "invalid", we can't really discard just 2424 * as we do not know its true length. So, to be safe, discard the 2425 * packet. 2426 */ 2427 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2428 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2429 2430 /* ADD-IP: Special case for ABORT chunks 2431 * F4) One special consideration is that ABORT Chunks arriving 2432 * destined to the IP address being deleted MUST be 2433 * ignored (see Section 5.3.1 for further details). 2434 */ 2435 if (SCTP_ADDR_DEL == 2436 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2437 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2438 2439 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2440 } 2441 2442 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2443 const struct sctp_endpoint *ep, 2444 const struct sctp_association *asoc, 2445 const sctp_subtype_t type, 2446 void *arg, 2447 sctp_cmd_seq_t *commands) 2448 { 2449 struct sctp_chunk *chunk = arg; 2450 unsigned int len; 2451 __be16 error = SCTP_ERROR_NO_ERROR; 2452 2453 /* See if we have an error cause code in the chunk. */ 2454 len = ntohs(chunk->chunk_hdr->length); 2455 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2456 2457 sctp_errhdr_t *err; 2458 sctp_walk_errors(err, chunk->chunk_hdr); 2459 if ((void *)err != (void *)chunk->chunk_end) 2460 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2461 2462 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2463 } 2464 2465 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2466 /* ASSOC_FAILED will DELETE_TCB. */ 2467 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2468 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2469 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2470 2471 return SCTP_DISPOSITION_ABORT; 2472 } 2473 2474 /* 2475 * Process an ABORT. (COOKIE-WAIT state) 2476 * 2477 * See sctp_sf_do_9_1_abort() above. 2478 */ 2479 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2480 const struct sctp_endpoint *ep, 2481 const struct sctp_association *asoc, 2482 const sctp_subtype_t type, 2483 void *arg, 2484 sctp_cmd_seq_t *commands) 2485 { 2486 struct sctp_chunk *chunk = arg; 2487 unsigned int len; 2488 __be16 error = SCTP_ERROR_NO_ERROR; 2489 2490 if (!sctp_vtag_verify_either(chunk, asoc)) 2491 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2492 2493 /* Make sure that the ABORT chunk has a valid length. 2494 * Since this is an ABORT chunk, we have to discard it 2495 * because of the following text: 2496 * RFC 2960, Section 3.3.7 2497 * If an endpoint receives an ABORT with a format error or for an 2498 * association that doesn't exist, it MUST silently discard it. 2499 * Because the length is "invalid", we can't really discard just 2500 * as we do not know its true length. So, to be safe, discard the 2501 * packet. 2502 */ 2503 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2504 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2505 2506 /* See if we have an error cause code in the chunk. */ 2507 len = ntohs(chunk->chunk_hdr->length); 2508 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2509 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2510 2511 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2512 chunk->transport); 2513 } 2514 2515 /* 2516 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2517 */ 2518 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2519 const struct sctp_endpoint *ep, 2520 const struct sctp_association *asoc, 2521 const sctp_subtype_t type, 2522 void *arg, 2523 sctp_cmd_seq_t *commands) 2524 { 2525 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2526 ENOPROTOOPT, asoc, 2527 (struct sctp_transport *)arg); 2528 } 2529 2530 /* 2531 * Process an ABORT. (COOKIE-ECHOED state) 2532 */ 2533 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2534 const struct sctp_endpoint *ep, 2535 const struct sctp_association *asoc, 2536 const sctp_subtype_t type, 2537 void *arg, 2538 sctp_cmd_seq_t *commands) 2539 { 2540 /* There is a single T1 timer, so we should be able to use 2541 * common function with the COOKIE-WAIT state. 2542 */ 2543 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2544 } 2545 2546 /* 2547 * Stop T1 timer and abort association with "INIT failed". 2548 * 2549 * This is common code called by several sctp_sf_*_abort() functions above. 2550 */ 2551 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2552 sctp_cmd_seq_t *commands, 2553 __be16 error, int sk_err, 2554 const struct sctp_association *asoc, 2555 struct sctp_transport *transport) 2556 { 2557 SCTP_DEBUG_PRINTK("ABORT received (INIT).\n"); 2558 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2559 SCTP_STATE(SCTP_STATE_CLOSED)); 2560 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2561 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2562 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2563 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2564 /* CMD_INIT_FAILED will DELETE_TCB. */ 2565 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2566 SCTP_PERR(error)); 2567 return SCTP_DISPOSITION_ABORT; 2568 } 2569 2570 /* 2571 * sctp_sf_do_9_2_shut 2572 * 2573 * Section: 9.2 2574 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2575 * - enter the SHUTDOWN-RECEIVED state, 2576 * 2577 * - stop accepting new data from its SCTP user 2578 * 2579 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2580 * that all its outstanding DATA chunks have been received by the 2581 * SHUTDOWN sender. 2582 * 2583 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2584 * send a SHUTDOWN in response to a ULP request. And should discard 2585 * subsequent SHUTDOWN chunks. 2586 * 2587 * If there are still outstanding DATA chunks left, the SHUTDOWN 2588 * receiver shall continue to follow normal data transmission 2589 * procedures defined in Section 6 until all outstanding DATA chunks 2590 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2591 * new data from its SCTP user. 2592 * 2593 * Verification Tag: 8.5 Verification Tag [Normal verification] 2594 * 2595 * Inputs 2596 * (endpoint, asoc, chunk) 2597 * 2598 * Outputs 2599 * (asoc, reply_msg, msg_up, timers, counters) 2600 * 2601 * The return value is the disposition of the chunk. 2602 */ 2603 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2604 const struct sctp_endpoint *ep, 2605 const struct sctp_association *asoc, 2606 const sctp_subtype_t type, 2607 void *arg, 2608 sctp_cmd_seq_t *commands) 2609 { 2610 struct sctp_chunk *chunk = arg; 2611 sctp_shutdownhdr_t *sdh; 2612 sctp_disposition_t disposition; 2613 struct sctp_ulpevent *ev; 2614 __u32 ctsn; 2615 2616 if (!sctp_vtag_verify(chunk, asoc)) 2617 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2618 2619 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2620 if (!sctp_chunk_length_valid(chunk, 2621 sizeof(struct sctp_shutdown_chunk_t))) 2622 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2623 commands); 2624 2625 /* Convert the elaborate header. */ 2626 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2627 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2628 chunk->subh.shutdown_hdr = sdh; 2629 ctsn = ntohl(sdh->cum_tsn_ack); 2630 2631 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2632 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2633 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2634 return SCTP_DISPOSITION_DISCARD; 2635 } 2636 2637 /* If Cumulative TSN Ack beyond the max tsn currently 2638 * send, terminating the association and respond to the 2639 * sender with an ABORT. 2640 */ 2641 if (!TSN_lt(ctsn, asoc->next_tsn)) 2642 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2643 2644 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2645 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2646 * inform the application that it should cease sending data. 2647 */ 2648 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2649 if (!ev) { 2650 disposition = SCTP_DISPOSITION_NOMEM; 2651 goto out; 2652 } 2653 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2654 2655 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2656 * - enter the SHUTDOWN-RECEIVED state, 2657 * - stop accepting new data from its SCTP user 2658 * 2659 * [This is implicit in the new state.] 2660 */ 2661 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2662 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2663 disposition = SCTP_DISPOSITION_CONSUME; 2664 2665 if (sctp_outq_is_empty(&asoc->outqueue)) { 2666 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2667 arg, commands); 2668 } 2669 2670 if (SCTP_DISPOSITION_NOMEM == disposition) 2671 goto out; 2672 2673 /* - verify, by checking the Cumulative TSN Ack field of the 2674 * chunk, that all its outstanding DATA chunks have been 2675 * received by the SHUTDOWN sender. 2676 */ 2677 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2678 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2679 2680 out: 2681 return disposition; 2682 } 2683 2684 /* 2685 * sctp_sf_do_9_2_shut_ctsn 2686 * 2687 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2688 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2689 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2690 * MUST be processed. 2691 */ 2692 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2693 const struct sctp_endpoint *ep, 2694 const struct sctp_association *asoc, 2695 const sctp_subtype_t type, 2696 void *arg, 2697 sctp_cmd_seq_t *commands) 2698 { 2699 struct sctp_chunk *chunk = arg; 2700 sctp_shutdownhdr_t *sdh; 2701 __u32 ctsn; 2702 2703 if (!sctp_vtag_verify(chunk, asoc)) 2704 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2705 2706 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2707 if (!sctp_chunk_length_valid(chunk, 2708 sizeof(struct sctp_shutdown_chunk_t))) 2709 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2710 commands); 2711 2712 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2713 ctsn = ntohl(sdh->cum_tsn_ack); 2714 2715 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2716 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 2717 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 2718 return SCTP_DISPOSITION_DISCARD; 2719 } 2720 2721 /* If Cumulative TSN Ack beyond the max tsn currently 2722 * send, terminating the association and respond to the 2723 * sender with an ABORT. 2724 */ 2725 if (!TSN_lt(ctsn, asoc->next_tsn)) 2726 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2727 2728 /* verify, by checking the Cumulative TSN Ack field of the 2729 * chunk, that all its outstanding DATA chunks have been 2730 * received by the SHUTDOWN sender. 2731 */ 2732 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2733 SCTP_BE32(sdh->cum_tsn_ack)); 2734 2735 return SCTP_DISPOSITION_CONSUME; 2736 } 2737 2738 /* RFC 2960 9.2 2739 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2740 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2741 * transport addresses (either in the IP addresses or in the INIT chunk) 2742 * that belong to this association, it should discard the INIT chunk and 2743 * retransmit the SHUTDOWN ACK chunk. 2744 */ 2745 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2746 const struct sctp_endpoint *ep, 2747 const struct sctp_association *asoc, 2748 const sctp_subtype_t type, 2749 void *arg, 2750 sctp_cmd_seq_t *commands) 2751 { 2752 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2753 struct sctp_chunk *reply; 2754 2755 /* Make sure that the chunk has a valid length */ 2756 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2757 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2758 commands); 2759 2760 /* Since we are not going to really process this INIT, there 2761 * is no point in verifying chunk boundries. Just generate 2762 * the SHUTDOWN ACK. 2763 */ 2764 reply = sctp_make_shutdown_ack(asoc, chunk); 2765 if (NULL == reply) 2766 goto nomem; 2767 2768 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2769 * the T2-SHUTDOWN timer. 2770 */ 2771 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2772 2773 /* and restart the T2-shutdown timer. */ 2774 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2775 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2776 2777 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2778 2779 return SCTP_DISPOSITION_CONSUME; 2780 nomem: 2781 return SCTP_DISPOSITION_NOMEM; 2782 } 2783 2784 /* 2785 * sctp_sf_do_ecn_cwr 2786 * 2787 * Section: Appendix A: Explicit Congestion Notification 2788 * 2789 * CWR: 2790 * 2791 * RFC 2481 details a specific bit for a sender to send in the header of 2792 * its next outbound TCP segment to indicate to its peer that it has 2793 * reduced its congestion window. This is termed the CWR bit. For 2794 * SCTP the same indication is made by including the CWR chunk. 2795 * This chunk contains one data element, i.e. the TSN number that 2796 * was sent in the ECNE chunk. This element represents the lowest 2797 * TSN number in the datagram that was originally marked with the 2798 * CE bit. 2799 * 2800 * Verification Tag: 8.5 Verification Tag [Normal verification] 2801 * Inputs 2802 * (endpoint, asoc, chunk) 2803 * 2804 * Outputs 2805 * (asoc, reply_msg, msg_up, timers, counters) 2806 * 2807 * The return value is the disposition of the chunk. 2808 */ 2809 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2810 const struct sctp_endpoint *ep, 2811 const struct sctp_association *asoc, 2812 const sctp_subtype_t type, 2813 void *arg, 2814 sctp_cmd_seq_t *commands) 2815 { 2816 sctp_cwrhdr_t *cwr; 2817 struct sctp_chunk *chunk = arg; 2818 u32 lowest_tsn; 2819 2820 if (!sctp_vtag_verify(chunk, asoc)) 2821 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2822 2823 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2824 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2825 commands); 2826 2827 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2828 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2829 2830 lowest_tsn = ntohl(cwr->lowest_tsn); 2831 2832 /* Does this CWR ack the last sent congestion notification? */ 2833 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2834 /* Stop sending ECNE. */ 2835 sctp_add_cmd_sf(commands, 2836 SCTP_CMD_ECN_CWR, 2837 SCTP_U32(lowest_tsn)); 2838 } 2839 return SCTP_DISPOSITION_CONSUME; 2840 } 2841 2842 /* 2843 * sctp_sf_do_ecne 2844 * 2845 * Section: Appendix A: Explicit Congestion Notification 2846 * 2847 * ECN-Echo 2848 * 2849 * RFC 2481 details a specific bit for a receiver to send back in its 2850 * TCP acknowledgements to notify the sender of the Congestion 2851 * Experienced (CE) bit having arrived from the network. For SCTP this 2852 * same indication is made by including the ECNE chunk. This chunk 2853 * contains one data element, i.e. the lowest TSN associated with the IP 2854 * datagram marked with the CE bit..... 2855 * 2856 * Verification Tag: 8.5 Verification Tag [Normal verification] 2857 * Inputs 2858 * (endpoint, asoc, chunk) 2859 * 2860 * Outputs 2861 * (asoc, reply_msg, msg_up, timers, counters) 2862 * 2863 * The return value is the disposition of the chunk. 2864 */ 2865 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2866 const struct sctp_endpoint *ep, 2867 const struct sctp_association *asoc, 2868 const sctp_subtype_t type, 2869 void *arg, 2870 sctp_cmd_seq_t *commands) 2871 { 2872 sctp_ecnehdr_t *ecne; 2873 struct sctp_chunk *chunk = arg; 2874 2875 if (!sctp_vtag_verify(chunk, asoc)) 2876 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2877 2878 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2879 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2880 commands); 2881 2882 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2883 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2884 2885 /* If this is a newer ECNE than the last CWR packet we sent out */ 2886 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2887 SCTP_U32(ntohl(ecne->lowest_tsn))); 2888 2889 return SCTP_DISPOSITION_CONSUME; 2890 } 2891 2892 /* 2893 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2894 * 2895 * The SCTP endpoint MUST always acknowledge the reception of each valid 2896 * DATA chunk. 2897 * 2898 * The guidelines on delayed acknowledgement algorithm specified in 2899 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2900 * acknowledgement SHOULD be generated for at least every second packet 2901 * (not every second DATA chunk) received, and SHOULD be generated within 2902 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2903 * situations it may be beneficial for an SCTP transmitter to be more 2904 * conservative than the algorithms detailed in this document allow. 2905 * However, an SCTP transmitter MUST NOT be more aggressive than the 2906 * following algorithms allow. 2907 * 2908 * A SCTP receiver MUST NOT generate more than one SACK for every 2909 * incoming packet, other than to update the offered window as the 2910 * receiving application consumes new data. 2911 * 2912 * Verification Tag: 8.5 Verification Tag [Normal verification] 2913 * 2914 * Inputs 2915 * (endpoint, asoc, chunk) 2916 * 2917 * Outputs 2918 * (asoc, reply_msg, msg_up, timers, counters) 2919 * 2920 * The return value is the disposition of the chunk. 2921 */ 2922 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2923 const struct sctp_endpoint *ep, 2924 const struct sctp_association *asoc, 2925 const sctp_subtype_t type, 2926 void *arg, 2927 sctp_cmd_seq_t *commands) 2928 { 2929 struct sctp_chunk *chunk = arg; 2930 sctp_arg_t force = SCTP_NOFORCE(); 2931 int error; 2932 2933 if (!sctp_vtag_verify(chunk, asoc)) { 2934 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2935 SCTP_NULL()); 2936 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2937 } 2938 2939 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2940 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2941 commands); 2942 2943 error = sctp_eat_data(asoc, chunk, commands ); 2944 switch (error) { 2945 case SCTP_IERROR_NO_ERROR: 2946 break; 2947 case SCTP_IERROR_HIGH_TSN: 2948 case SCTP_IERROR_BAD_STREAM: 2949 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2950 goto discard_noforce; 2951 case SCTP_IERROR_DUP_TSN: 2952 case SCTP_IERROR_IGNORE_TSN: 2953 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2954 goto discard_force; 2955 case SCTP_IERROR_NO_DATA: 2956 goto consume; 2957 case SCTP_IERROR_PROTO_VIOLATION: 2958 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 2959 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2960 default: 2961 BUG(); 2962 } 2963 2964 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2965 force = SCTP_FORCE(); 2966 2967 if (asoc->autoclose) { 2968 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2969 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2970 } 2971 2972 /* If this is the last chunk in a packet, we need to count it 2973 * toward sack generation. Note that we need to SACK every 2974 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2975 * THEM. We elect to NOT generate SACK's if the chunk fails 2976 * the verification tag test. 2977 * 2978 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2979 * 2980 * The SCTP endpoint MUST always acknowledge the reception of 2981 * each valid DATA chunk. 2982 * 2983 * The guidelines on delayed acknowledgement algorithm 2984 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2985 * Specifically, an acknowledgement SHOULD be generated for at 2986 * least every second packet (not every second DATA chunk) 2987 * received, and SHOULD be generated within 200 ms of the 2988 * arrival of any unacknowledged DATA chunk. In some 2989 * situations it may be beneficial for an SCTP transmitter to 2990 * be more conservative than the algorithms detailed in this 2991 * document allow. However, an SCTP transmitter MUST NOT be 2992 * more aggressive than the following algorithms allow. 2993 */ 2994 if (chunk->end_of_packet) 2995 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 2996 2997 return SCTP_DISPOSITION_CONSUME; 2998 2999 discard_force: 3000 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3001 * 3002 * When a packet arrives with duplicate DATA chunk(s) and with 3003 * no new DATA chunk(s), the endpoint MUST immediately send a 3004 * SACK with no delay. If a packet arrives with duplicate 3005 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3006 * MAY immediately send a SACK. Normally receipt of duplicate 3007 * DATA chunks will occur when the original SACK chunk was lost 3008 * and the peer's RTO has expired. The duplicate TSN number(s) 3009 * SHOULD be reported in the SACK as duplicate. 3010 */ 3011 /* In our case, we split the MAY SACK advice up whether or not 3012 * the last chunk is a duplicate.' 3013 */ 3014 if (chunk->end_of_packet) 3015 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3016 return SCTP_DISPOSITION_DISCARD; 3017 3018 discard_noforce: 3019 if (chunk->end_of_packet) 3020 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3021 3022 return SCTP_DISPOSITION_DISCARD; 3023 consume: 3024 return SCTP_DISPOSITION_CONSUME; 3025 3026 } 3027 3028 /* 3029 * sctp_sf_eat_data_fast_4_4 3030 * 3031 * Section: 4 (4) 3032 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3033 * DATA chunks without delay. 3034 * 3035 * Verification Tag: 8.5 Verification Tag [Normal verification] 3036 * Inputs 3037 * (endpoint, asoc, chunk) 3038 * 3039 * Outputs 3040 * (asoc, reply_msg, msg_up, timers, counters) 3041 * 3042 * The return value is the disposition of the chunk. 3043 */ 3044 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3045 const struct sctp_endpoint *ep, 3046 const struct sctp_association *asoc, 3047 const sctp_subtype_t type, 3048 void *arg, 3049 sctp_cmd_seq_t *commands) 3050 { 3051 struct sctp_chunk *chunk = arg; 3052 int error; 3053 3054 if (!sctp_vtag_verify(chunk, asoc)) { 3055 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3056 SCTP_NULL()); 3057 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3058 } 3059 3060 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3061 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3062 commands); 3063 3064 error = sctp_eat_data(asoc, chunk, commands ); 3065 switch (error) { 3066 case SCTP_IERROR_NO_ERROR: 3067 case SCTP_IERROR_HIGH_TSN: 3068 case SCTP_IERROR_DUP_TSN: 3069 case SCTP_IERROR_IGNORE_TSN: 3070 case SCTP_IERROR_BAD_STREAM: 3071 break; 3072 case SCTP_IERROR_NO_DATA: 3073 goto consume; 3074 case SCTP_IERROR_PROTO_VIOLATION: 3075 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3076 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3077 default: 3078 BUG(); 3079 } 3080 3081 /* Go a head and force a SACK, since we are shutting down. */ 3082 3083 /* Implementor's Guide. 3084 * 3085 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3086 * respond to each received packet containing one or more DATA chunk(s) 3087 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3088 */ 3089 if (chunk->end_of_packet) { 3090 /* We must delay the chunk creation since the cumulative 3091 * TSN has not been updated yet. 3092 */ 3093 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3094 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3095 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3096 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3097 } 3098 3099 consume: 3100 return SCTP_DISPOSITION_CONSUME; 3101 } 3102 3103 /* 3104 * Section: 6.2 Processing a Received SACK 3105 * D) Any time a SACK arrives, the endpoint performs the following: 3106 * 3107 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3108 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3109 * increasing, a SACK whose Cumulative TSN Ack is less than the 3110 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3111 * 3112 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3113 * of bytes still outstanding after processing the Cumulative TSN Ack 3114 * and the Gap Ack Blocks. 3115 * 3116 * iii) If the SACK is missing a TSN that was previously 3117 * acknowledged via a Gap Ack Block (e.g., the data receiver 3118 * reneged on the data), then mark the corresponding DATA chunk 3119 * as available for retransmit: Mark it as missing for fast 3120 * retransmit as described in Section 7.2.4 and if no retransmit 3121 * timer is running for the destination address to which the DATA 3122 * chunk was originally transmitted, then T3-rtx is started for 3123 * that destination address. 3124 * 3125 * Verification Tag: 8.5 Verification Tag [Normal verification] 3126 * 3127 * Inputs 3128 * (endpoint, asoc, chunk) 3129 * 3130 * Outputs 3131 * (asoc, reply_msg, msg_up, timers, counters) 3132 * 3133 * The return value is the disposition of the chunk. 3134 */ 3135 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3136 const struct sctp_endpoint *ep, 3137 const struct sctp_association *asoc, 3138 const sctp_subtype_t type, 3139 void *arg, 3140 sctp_cmd_seq_t *commands) 3141 { 3142 struct sctp_chunk *chunk = arg; 3143 sctp_sackhdr_t *sackh; 3144 __u32 ctsn; 3145 3146 if (!sctp_vtag_verify(chunk, asoc)) 3147 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3148 3149 /* Make sure that the SACK chunk has a valid length. */ 3150 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3151 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3152 commands); 3153 3154 /* Pull the SACK chunk from the data buffer */ 3155 sackh = sctp_sm_pull_sack(chunk); 3156 /* Was this a bogus SACK? */ 3157 if (!sackh) 3158 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3159 chunk->subh.sack_hdr = sackh; 3160 ctsn = ntohl(sackh->cum_tsn_ack); 3161 3162 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3163 * Ack Point, then drop the SACK. Since Cumulative TSN 3164 * Ack is monotonically increasing, a SACK whose 3165 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3166 * Point indicates an out-of-order SACK. 3167 */ 3168 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3169 SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); 3170 SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); 3171 return SCTP_DISPOSITION_DISCARD; 3172 } 3173 3174 /* If Cumulative TSN Ack beyond the max tsn currently 3175 * send, terminating the association and respond to the 3176 * sender with an ABORT. 3177 */ 3178 if (!TSN_lt(ctsn, asoc->next_tsn)) 3179 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3180 3181 /* Return this SACK for further processing. */ 3182 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); 3183 3184 /* Note: We do the rest of the work on the PROCESS_SACK 3185 * sideeffect. 3186 */ 3187 return SCTP_DISPOSITION_CONSUME; 3188 } 3189 3190 /* 3191 * Generate an ABORT in response to a packet. 3192 * 3193 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3194 * 3195 * 8) The receiver should respond to the sender of the OOTB packet with 3196 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3197 * MUST fill in the Verification Tag field of the outbound packet 3198 * with the value found in the Verification Tag field of the OOTB 3199 * packet and set the T-bit in the Chunk Flags to indicate that the 3200 * Verification Tag is reflected. After sending this ABORT, the 3201 * receiver of the OOTB packet shall discard the OOTB packet and take 3202 * no further action. 3203 * 3204 * Verification Tag: 3205 * 3206 * The return value is the disposition of the chunk. 3207 */ 3208 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3209 const struct sctp_endpoint *ep, 3210 const struct sctp_association *asoc, 3211 const sctp_subtype_t type, 3212 void *arg, 3213 sctp_cmd_seq_t *commands) 3214 { 3215 struct sctp_packet *packet = NULL; 3216 struct sctp_chunk *chunk = arg; 3217 struct sctp_chunk *abort; 3218 3219 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3220 3221 if (packet) { 3222 /* Make an ABORT. The T bit will be set if the asoc 3223 * is NULL. 3224 */ 3225 abort = sctp_make_abort(asoc, chunk, 0); 3226 if (!abort) { 3227 sctp_ootb_pkt_free(packet); 3228 return SCTP_DISPOSITION_NOMEM; 3229 } 3230 3231 /* Reflect vtag if T-Bit is set */ 3232 if (sctp_test_T_bit(abort)) 3233 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3234 3235 /* Set the skb to the belonging sock for accounting. */ 3236 abort->skb->sk = ep->base.sk; 3237 3238 sctp_packet_append_chunk(packet, abort); 3239 3240 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3241 SCTP_PACKET(packet)); 3242 3243 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3244 3245 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3246 return SCTP_DISPOSITION_CONSUME; 3247 } 3248 3249 return SCTP_DISPOSITION_NOMEM; 3250 } 3251 3252 /* 3253 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3254 * event as ULP notification for each cause included in the chunk. 3255 * 3256 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3257 * 3258 * The return value is the disposition of the chunk. 3259 */ 3260 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3261 const struct sctp_endpoint *ep, 3262 const struct sctp_association *asoc, 3263 const sctp_subtype_t type, 3264 void *arg, 3265 sctp_cmd_seq_t *commands) 3266 { 3267 struct sctp_chunk *chunk = arg; 3268 sctp_errhdr_t *err; 3269 3270 if (!sctp_vtag_verify(chunk, asoc)) 3271 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3272 3273 /* Make sure that the ERROR chunk has a valid length. */ 3274 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3275 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3276 commands); 3277 sctp_walk_errors(err, chunk->chunk_hdr); 3278 if ((void *)err != (void *)chunk->chunk_end) 3279 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3280 (void *)err, commands); 3281 3282 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3283 SCTP_CHUNK(chunk)); 3284 3285 return SCTP_DISPOSITION_CONSUME; 3286 } 3287 3288 /* 3289 * Process an inbound SHUTDOWN ACK. 3290 * 3291 * From Section 9.2: 3292 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3293 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3294 * peer, and remove all record of the association. 3295 * 3296 * The return value is the disposition. 3297 */ 3298 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3299 const struct sctp_endpoint *ep, 3300 const struct sctp_association *asoc, 3301 const sctp_subtype_t type, 3302 void *arg, 3303 sctp_cmd_seq_t *commands) 3304 { 3305 struct sctp_chunk *chunk = arg; 3306 struct sctp_chunk *reply; 3307 struct sctp_ulpevent *ev; 3308 3309 if (!sctp_vtag_verify(chunk, asoc)) 3310 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3311 3312 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3313 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3314 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3315 commands); 3316 /* 10.2 H) SHUTDOWN COMPLETE notification 3317 * 3318 * When SCTP completes the shutdown procedures (section 9.2) this 3319 * notification is passed to the upper layer. 3320 */ 3321 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3322 0, 0, 0, NULL, GFP_ATOMIC); 3323 if (!ev) 3324 goto nomem; 3325 3326 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3327 reply = sctp_make_shutdown_complete(asoc, chunk); 3328 if (!reply) 3329 goto nomem_chunk; 3330 3331 /* Do all the commands now (after allocation), so that we 3332 * have consistent state if memory allocation failes 3333 */ 3334 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3335 3336 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3337 * stop the T2-shutdown timer, 3338 */ 3339 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3340 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3341 3342 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3343 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3344 3345 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3346 SCTP_STATE(SCTP_STATE_CLOSED)); 3347 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3348 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3349 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3350 3351 /* ...and remove all record of the association. */ 3352 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3353 return SCTP_DISPOSITION_DELETE_TCB; 3354 3355 nomem_chunk: 3356 sctp_ulpevent_free(ev); 3357 nomem: 3358 return SCTP_DISPOSITION_NOMEM; 3359 } 3360 3361 /* 3362 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3363 * 3364 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3365 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3366 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3367 * packet must fill in the Verification Tag field of the outbound 3368 * packet with the Verification Tag received in the SHUTDOWN ACK and 3369 * set the T-bit in the Chunk Flags to indicate that the Verification 3370 * Tag is reflected. 3371 * 3372 * 8) The receiver should respond to the sender of the OOTB packet with 3373 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3374 * MUST fill in the Verification Tag field of the outbound packet 3375 * with the value found in the Verification Tag field of the OOTB 3376 * packet and set the T-bit in the Chunk Flags to indicate that the 3377 * Verification Tag is reflected. After sending this ABORT, the 3378 * receiver of the OOTB packet shall discard the OOTB packet and take 3379 * no further action. 3380 */ 3381 sctp_disposition_t sctp_sf_ootb(struct net *net, 3382 const struct sctp_endpoint *ep, 3383 const struct sctp_association *asoc, 3384 const sctp_subtype_t type, 3385 void *arg, 3386 sctp_cmd_seq_t *commands) 3387 { 3388 struct sctp_chunk *chunk = arg; 3389 struct sk_buff *skb = chunk->skb; 3390 sctp_chunkhdr_t *ch; 3391 sctp_errhdr_t *err; 3392 __u8 *ch_end; 3393 int ootb_shut_ack = 0; 3394 int ootb_cookie_ack = 0; 3395 3396 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3397 3398 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3399 do { 3400 /* Report violation if the chunk is less then minimal */ 3401 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3402 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3403 commands); 3404 3405 /* Now that we know we at least have a chunk header, 3406 * do things that are type appropriate. 3407 */ 3408 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3409 ootb_shut_ack = 1; 3410 3411 /* RFC 2960, Section 3.3.7 3412 * Moreover, under any circumstances, an endpoint that 3413 * receives an ABORT MUST NOT respond to that ABORT by 3414 * sending an ABORT of its own. 3415 */ 3416 if (SCTP_CID_ABORT == ch->type) 3417 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3418 3419 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3420 * or a COOKIE ACK the SCTP Packet should be silently 3421 * discarded. 3422 */ 3423 3424 if (SCTP_CID_COOKIE_ACK == ch->type) 3425 ootb_cookie_ack = 1; 3426 3427 if (SCTP_CID_ERROR == ch->type) { 3428 sctp_walk_errors(err, ch) { 3429 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3430 ootb_cookie_ack = 1; 3431 break; 3432 } 3433 } 3434 } 3435 3436 /* Report violation if chunk len overflows */ 3437 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3438 if (ch_end > skb_tail_pointer(skb)) 3439 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3440 commands); 3441 3442 ch = (sctp_chunkhdr_t *) ch_end; 3443 } while (ch_end < skb_tail_pointer(skb)); 3444 3445 if (ootb_shut_ack) 3446 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3447 else if (ootb_cookie_ack) 3448 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3449 else 3450 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3451 } 3452 3453 /* 3454 * Handle an "Out of the blue" SHUTDOWN ACK. 3455 * 3456 * Section: 8.4 5, sctpimpguide 2.41. 3457 * 3458 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3459 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3460 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3461 * packet must fill in the Verification Tag field of the outbound 3462 * packet with the Verification Tag received in the SHUTDOWN ACK and 3463 * set the T-bit in the Chunk Flags to indicate that the Verification 3464 * Tag is reflected. 3465 * 3466 * Inputs 3467 * (endpoint, asoc, type, arg, commands) 3468 * 3469 * Outputs 3470 * (sctp_disposition_t) 3471 * 3472 * The return value is the disposition of the chunk. 3473 */ 3474 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3475 const struct sctp_endpoint *ep, 3476 const struct sctp_association *asoc, 3477 const sctp_subtype_t type, 3478 void *arg, 3479 sctp_cmd_seq_t *commands) 3480 { 3481 struct sctp_packet *packet = NULL; 3482 struct sctp_chunk *chunk = arg; 3483 struct sctp_chunk *shut; 3484 3485 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3486 3487 if (packet) { 3488 /* Make an SHUTDOWN_COMPLETE. 3489 * The T bit will be set if the asoc is NULL. 3490 */ 3491 shut = sctp_make_shutdown_complete(asoc, chunk); 3492 if (!shut) { 3493 sctp_ootb_pkt_free(packet); 3494 return SCTP_DISPOSITION_NOMEM; 3495 } 3496 3497 /* Reflect vtag if T-Bit is set */ 3498 if (sctp_test_T_bit(shut)) 3499 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3500 3501 /* Set the skb to the belonging sock for accounting. */ 3502 shut->skb->sk = ep->base.sk; 3503 3504 sctp_packet_append_chunk(packet, shut); 3505 3506 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3507 SCTP_PACKET(packet)); 3508 3509 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3510 3511 /* If the chunk length is invalid, we don't want to process 3512 * the reset of the packet. 3513 */ 3514 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3515 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3516 3517 /* We need to discard the rest of the packet to prevent 3518 * potential bomming attacks from additional bundled chunks. 3519 * This is documented in SCTP Threats ID. 3520 */ 3521 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3522 } 3523 3524 return SCTP_DISPOSITION_NOMEM; 3525 } 3526 3527 /* 3528 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3529 * 3530 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3531 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3532 * procedures in section 8.4 SHOULD be followed, in other words it 3533 * should be treated as an Out Of The Blue packet. 3534 * [This means that we do NOT check the Verification Tag on these 3535 * chunks. --piggy ] 3536 * 3537 */ 3538 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3539 const struct sctp_endpoint *ep, 3540 const struct sctp_association *asoc, 3541 const sctp_subtype_t type, 3542 void *arg, 3543 sctp_cmd_seq_t *commands) 3544 { 3545 struct sctp_chunk *chunk = arg; 3546 3547 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3548 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3549 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3550 commands); 3551 3552 /* Although we do have an association in this case, it corresponds 3553 * to a restarted association. So the packet is treated as an OOTB 3554 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3555 * called with a NULL association. 3556 */ 3557 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3558 3559 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3560 } 3561 3562 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3563 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3564 const struct sctp_endpoint *ep, 3565 const struct sctp_association *asoc, 3566 const sctp_subtype_t type, void *arg, 3567 sctp_cmd_seq_t *commands) 3568 { 3569 struct sctp_chunk *chunk = arg; 3570 struct sctp_chunk *asconf_ack = NULL; 3571 struct sctp_paramhdr *err_param = NULL; 3572 sctp_addiphdr_t *hdr; 3573 union sctp_addr_param *addr_param; 3574 __u32 serial; 3575 int length; 3576 3577 if (!sctp_vtag_verify(chunk, asoc)) { 3578 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3579 SCTP_NULL()); 3580 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3581 } 3582 3583 /* ADD-IP: Section 4.1.1 3584 * This chunk MUST be sent in an authenticated way by using 3585 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3586 * is received unauthenticated it MUST be silently discarded as 3587 * described in [I-D.ietf-tsvwg-sctp-auth]. 3588 */ 3589 if (!net->sctp.addip_noauth && !chunk->auth) 3590 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3591 3592 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3593 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3594 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3595 commands); 3596 3597 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3598 serial = ntohl(hdr->serial); 3599 3600 addr_param = (union sctp_addr_param *)hdr->params; 3601 length = ntohs(addr_param->p.length); 3602 if (length < sizeof(sctp_paramhdr_t)) 3603 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3604 (void *)addr_param, commands); 3605 3606 /* Verify the ASCONF chunk before processing it. */ 3607 if (!sctp_verify_asconf(asoc, 3608 (sctp_paramhdr_t *)((void *)addr_param + length), 3609 (void *)chunk->chunk_end, 3610 &err_param)) 3611 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3612 (void *)err_param, commands); 3613 3614 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3615 * the endpoint stored in a new association variable 3616 * 'Peer-Serial-Number'. 3617 */ 3618 if (serial == asoc->peer.addip_serial + 1) { 3619 /* If this is the first instance of ASCONF in the packet, 3620 * we can clean our old ASCONF-ACKs. 3621 */ 3622 if (!chunk->has_asconf) 3623 sctp_assoc_clean_asconf_ack_cache(asoc); 3624 3625 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3626 * expected, process the ASCONF as described below and after 3627 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3628 * the response packet and cache a copy of it (in the event it 3629 * later needs to be retransmitted). 3630 * 3631 * Essentially, do V1-V5. 3632 */ 3633 asconf_ack = sctp_process_asconf((struct sctp_association *) 3634 asoc, chunk); 3635 if (!asconf_ack) 3636 return SCTP_DISPOSITION_NOMEM; 3637 } else if (serial < asoc->peer.addip_serial + 1) { 3638 /* ADDIP 5.2 E2) 3639 * If the value found in the Sequence Number is less than the 3640 * ('Peer- Sequence-Number' + 1), simply skip to the next 3641 * ASCONF, and include in the outbound response packet 3642 * any previously cached ASCONF-ACK response that was 3643 * sent and saved that matches the Sequence Number of the 3644 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3645 * Chunk exists. This will occur when an older ASCONF 3646 * arrives out of order. In such a case, the receiver 3647 * should skip the ASCONF Chunk and not include ASCONF-ACK 3648 * Chunk for that chunk. 3649 */ 3650 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3651 if (!asconf_ack) 3652 return SCTP_DISPOSITION_DISCARD; 3653 3654 /* Reset the transport so that we select the correct one 3655 * this time around. This is to make sure that we don't 3656 * accidentally use a stale transport that's been removed. 3657 */ 3658 asconf_ack->transport = NULL; 3659 } else { 3660 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3661 * it must be either a stale packet or from an attacker. 3662 */ 3663 return SCTP_DISPOSITION_DISCARD; 3664 } 3665 3666 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3667 * containing the ASCONF-ACK Chunks MUST be the source address of 3668 * the SCTP packet that held the ASCONF Chunks. 3669 * 3670 * To do this properly, we'll set the destination address of the chunk 3671 * and at the transmit time, will try look up the transport to use. 3672 * Since ASCONFs may be bundled, the correct transport may not be 3673 * created until we process the entire packet, thus this workaround. 3674 */ 3675 asconf_ack->dest = chunk->source; 3676 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3677 if (asoc->new_transport) { 3678 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, 3679 commands); 3680 ((struct sctp_association *)asoc)->new_transport = NULL; 3681 } 3682 3683 return SCTP_DISPOSITION_CONSUME; 3684 } 3685 3686 /* 3687 * ADDIP Section 4.3 General rules for address manipulation 3688 * When building TLV parameters for the ASCONF Chunk that will add or 3689 * delete IP addresses the D0 to D13 rules should be applied: 3690 */ 3691 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3692 const struct sctp_endpoint *ep, 3693 const struct sctp_association *asoc, 3694 const sctp_subtype_t type, void *arg, 3695 sctp_cmd_seq_t *commands) 3696 { 3697 struct sctp_chunk *asconf_ack = arg; 3698 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3699 struct sctp_chunk *abort; 3700 struct sctp_paramhdr *err_param = NULL; 3701 sctp_addiphdr_t *addip_hdr; 3702 __u32 sent_serial, rcvd_serial; 3703 3704 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3705 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3706 SCTP_NULL()); 3707 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3708 } 3709 3710 /* ADD-IP, Section 4.1.2: 3711 * This chunk MUST be sent in an authenticated way by using 3712 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3713 * is received unauthenticated it MUST be silently discarded as 3714 * described in [I-D.ietf-tsvwg-sctp-auth]. 3715 */ 3716 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3717 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3718 3719 /* Make sure that the ADDIP chunk has a valid length. */ 3720 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3721 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3722 commands); 3723 3724 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3725 rcvd_serial = ntohl(addip_hdr->serial); 3726 3727 /* Verify the ASCONF-ACK chunk before processing it. */ 3728 if (!sctp_verify_asconf(asoc, 3729 (sctp_paramhdr_t *)addip_hdr->params, 3730 (void *)asconf_ack->chunk_end, 3731 &err_param)) 3732 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3733 (void *)err_param, commands); 3734 3735 if (last_asconf) { 3736 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3737 sent_serial = ntohl(addip_hdr->serial); 3738 } else { 3739 sent_serial = asoc->addip_serial - 1; 3740 } 3741 3742 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3743 * equal to the next serial number to be used but no ASCONF chunk is 3744 * outstanding the endpoint MUST ABORT the association. Note that a 3745 * sequence number is greater than if it is no more than 2^^31-1 3746 * larger than the current sequence number (using serial arithmetic). 3747 */ 3748 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3749 !(asoc->addip_last_asconf)) { 3750 abort = sctp_make_abort(asoc, asconf_ack, 3751 sizeof(sctp_errhdr_t)); 3752 if (abort) { 3753 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3754 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3755 SCTP_CHUNK(abort)); 3756 } 3757 /* We are going to ABORT, so we might as well stop 3758 * processing the rest of the chunks in the packet. 3759 */ 3760 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3761 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3762 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3763 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3764 SCTP_ERROR(ECONNABORTED)); 3765 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3766 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3767 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3768 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3769 return SCTP_DISPOSITION_ABORT; 3770 } 3771 3772 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3773 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3774 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3775 3776 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3777 asconf_ack)) { 3778 /* Successfully processed ASCONF_ACK. We can 3779 * release the next asconf if we have one. 3780 */ 3781 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3782 SCTP_NULL()); 3783 return SCTP_DISPOSITION_CONSUME; 3784 } 3785 3786 abort = sctp_make_abort(asoc, asconf_ack, 3787 sizeof(sctp_errhdr_t)); 3788 if (abort) { 3789 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3790 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3791 SCTP_CHUNK(abort)); 3792 } 3793 /* We are going to ABORT, so we might as well stop 3794 * processing the rest of the chunks in the packet. 3795 */ 3796 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3797 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3798 SCTP_ERROR(ECONNABORTED)); 3799 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3800 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3801 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3802 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3803 return SCTP_DISPOSITION_ABORT; 3804 } 3805 3806 return SCTP_DISPOSITION_DISCARD; 3807 } 3808 3809 /* 3810 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3811 * 3812 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3813 * its cumulative TSN point to the value carried in the FORWARD TSN 3814 * chunk, and then MUST further advance its cumulative TSN point locally 3815 * if possible. 3816 * After the above processing, the data receiver MUST stop reporting any 3817 * missing TSNs earlier than or equal to the new cumulative TSN point. 3818 * 3819 * Verification Tag: 8.5 Verification Tag [Normal verification] 3820 * 3821 * The return value is the disposition of the chunk. 3822 */ 3823 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3824 const struct sctp_endpoint *ep, 3825 const struct sctp_association *asoc, 3826 const sctp_subtype_t type, 3827 void *arg, 3828 sctp_cmd_seq_t *commands) 3829 { 3830 struct sctp_chunk *chunk = arg; 3831 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3832 struct sctp_fwdtsn_skip *skip; 3833 __u16 len; 3834 __u32 tsn; 3835 3836 if (!sctp_vtag_verify(chunk, asoc)) { 3837 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3838 SCTP_NULL()); 3839 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3840 } 3841 3842 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3843 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3844 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3845 commands); 3846 3847 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3848 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3849 len = ntohs(chunk->chunk_hdr->length); 3850 len -= sizeof(struct sctp_chunkhdr); 3851 skb_pull(chunk->skb, len); 3852 3853 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3854 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3855 3856 /* The TSN is too high--silently discard the chunk and count on it 3857 * getting retransmitted later. 3858 */ 3859 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3860 goto discard_noforce; 3861 3862 /* Silently discard the chunk if stream-id is not valid */ 3863 sctp_walk_fwdtsn(skip, chunk) { 3864 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3865 goto discard_noforce; 3866 } 3867 3868 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3869 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3870 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3871 SCTP_CHUNK(chunk)); 3872 3873 /* Count this as receiving DATA. */ 3874 if (asoc->autoclose) { 3875 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3876 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3877 } 3878 3879 /* FIXME: For now send a SACK, but DATA processing may 3880 * send another. 3881 */ 3882 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3883 3884 return SCTP_DISPOSITION_CONSUME; 3885 3886 discard_noforce: 3887 return SCTP_DISPOSITION_DISCARD; 3888 } 3889 3890 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3891 struct net *net, 3892 const struct sctp_endpoint *ep, 3893 const struct sctp_association *asoc, 3894 const sctp_subtype_t type, 3895 void *arg, 3896 sctp_cmd_seq_t *commands) 3897 { 3898 struct sctp_chunk *chunk = arg; 3899 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3900 struct sctp_fwdtsn_skip *skip; 3901 __u16 len; 3902 __u32 tsn; 3903 3904 if (!sctp_vtag_verify(chunk, asoc)) { 3905 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3906 SCTP_NULL()); 3907 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3908 } 3909 3910 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3911 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3912 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3913 commands); 3914 3915 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3916 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3917 len = ntohs(chunk->chunk_hdr->length); 3918 len -= sizeof(struct sctp_chunkhdr); 3919 skb_pull(chunk->skb, len); 3920 3921 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3922 SCTP_DEBUG_PRINTK("%s: TSN 0x%x.\n", __func__, tsn); 3923 3924 /* The TSN is too high--silently discard the chunk and count on it 3925 * getting retransmitted later. 3926 */ 3927 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3928 goto gen_shutdown; 3929 3930 /* Silently discard the chunk if stream-id is not valid */ 3931 sctp_walk_fwdtsn(skip, chunk) { 3932 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3933 goto gen_shutdown; 3934 } 3935 3936 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3937 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3938 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3939 SCTP_CHUNK(chunk)); 3940 3941 /* Go a head and force a SACK, since we are shutting down. */ 3942 gen_shutdown: 3943 /* Implementor's Guide. 3944 * 3945 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3946 * respond to each received packet containing one or more DATA chunk(s) 3947 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3948 */ 3949 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3950 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3951 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3952 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3953 3954 return SCTP_DISPOSITION_CONSUME; 3955 } 3956 3957 /* 3958 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3959 * 3960 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3961 * Identifier field. If this algorithm was not specified by the 3962 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3963 * during association setup, the AUTH chunk and all chunks after it MUST 3964 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3965 * defined in Section 4.1. 3966 * 3967 * If an endpoint with no shared key receives a Shared Key Identifier 3968 * other than 0, it MUST silently discard all authenticated chunks. If 3969 * the endpoint has at least one endpoint pair shared key for the peer, 3970 * it MUST use the key specified by the Shared Key Identifier if a 3971 * key has been configured for that Shared Key Identifier. If no 3972 * endpoint pair shared key has been configured for that Shared Key 3973 * Identifier, all authenticated chunks MUST be silently discarded. 3974 * 3975 * Verification Tag: 8.5 Verification Tag [Normal verification] 3976 * 3977 * The return value is the disposition of the chunk. 3978 */ 3979 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 3980 const struct sctp_endpoint *ep, 3981 const struct sctp_association *asoc, 3982 const sctp_subtype_t type, 3983 struct sctp_chunk *chunk) 3984 { 3985 struct sctp_authhdr *auth_hdr; 3986 struct sctp_hmac *hmac; 3987 unsigned int sig_len; 3988 __u16 key_id; 3989 __u8 *save_digest; 3990 __u8 *digest; 3991 3992 /* Pull in the auth header, so we can do some more verification */ 3993 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3994 chunk->subh.auth_hdr = auth_hdr; 3995 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 3996 3997 /* Make sure that we suport the HMAC algorithm from the auth 3998 * chunk. 3999 */ 4000 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4001 return SCTP_IERROR_AUTH_BAD_HMAC; 4002 4003 /* Make sure that the provided shared key identifier has been 4004 * configured 4005 */ 4006 key_id = ntohs(auth_hdr->shkey_id); 4007 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4008 return SCTP_IERROR_AUTH_BAD_KEYID; 4009 4010 4011 /* Make sure that the length of the signature matches what 4012 * we expect. 4013 */ 4014 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4015 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4016 if (sig_len != hmac->hmac_len) 4017 return SCTP_IERROR_PROTO_VIOLATION; 4018 4019 /* Now that we've done validation checks, we can compute and 4020 * verify the hmac. The steps involved are: 4021 * 1. Save the digest from the chunk. 4022 * 2. Zero out the digest in the chunk. 4023 * 3. Compute the new digest 4024 * 4. Compare saved and new digests. 4025 */ 4026 digest = auth_hdr->hmac; 4027 skb_pull(chunk->skb, sig_len); 4028 4029 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4030 if (!save_digest) 4031 goto nomem; 4032 4033 memset(digest, 0, sig_len); 4034 4035 sctp_auth_calculate_hmac(asoc, chunk->skb, 4036 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4037 GFP_ATOMIC); 4038 4039 /* Discard the packet if the digests do not match */ 4040 if (memcmp(save_digest, digest, sig_len)) { 4041 kfree(save_digest); 4042 return SCTP_IERROR_BAD_SIG; 4043 } 4044 4045 kfree(save_digest); 4046 chunk->auth = 1; 4047 4048 return SCTP_IERROR_NO_ERROR; 4049 nomem: 4050 return SCTP_IERROR_NOMEM; 4051 } 4052 4053 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4054 const struct sctp_endpoint *ep, 4055 const struct sctp_association *asoc, 4056 const sctp_subtype_t type, 4057 void *arg, 4058 sctp_cmd_seq_t *commands) 4059 { 4060 struct sctp_authhdr *auth_hdr; 4061 struct sctp_chunk *chunk = arg; 4062 struct sctp_chunk *err_chunk; 4063 sctp_ierror_t error; 4064 4065 /* Make sure that the peer has AUTH capable */ 4066 if (!asoc->peer.auth_capable) 4067 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4068 4069 if (!sctp_vtag_verify(chunk, asoc)) { 4070 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4071 SCTP_NULL()); 4072 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4073 } 4074 4075 /* Make sure that the AUTH chunk has valid length. */ 4076 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4077 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4078 commands); 4079 4080 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4081 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4082 switch (error) { 4083 case SCTP_IERROR_AUTH_BAD_HMAC: 4084 /* Generate the ERROR chunk and discard the rest 4085 * of the packet 4086 */ 4087 err_chunk = sctp_make_op_error(asoc, chunk, 4088 SCTP_ERROR_UNSUP_HMAC, 4089 &auth_hdr->hmac_id, 4090 sizeof(__u16), 0); 4091 if (err_chunk) { 4092 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4093 SCTP_CHUNK(err_chunk)); 4094 } 4095 /* Fall Through */ 4096 case SCTP_IERROR_AUTH_BAD_KEYID: 4097 case SCTP_IERROR_BAD_SIG: 4098 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4099 4100 case SCTP_IERROR_PROTO_VIOLATION: 4101 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4102 commands); 4103 4104 case SCTP_IERROR_NOMEM: 4105 return SCTP_DISPOSITION_NOMEM; 4106 4107 default: /* Prevent gcc warnings */ 4108 break; 4109 } 4110 4111 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4112 struct sctp_ulpevent *ev; 4113 4114 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4115 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4116 4117 if (!ev) 4118 return -ENOMEM; 4119 4120 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4121 SCTP_ULPEVENT(ev)); 4122 } 4123 4124 return SCTP_DISPOSITION_CONSUME; 4125 } 4126 4127 /* 4128 * Process an unknown chunk. 4129 * 4130 * Section: 3.2. Also, 2.1 in the implementor's guide. 4131 * 4132 * Chunk Types are encoded such that the highest-order two bits specify 4133 * the action that must be taken if the processing endpoint does not 4134 * recognize the Chunk Type. 4135 * 4136 * 00 - Stop processing this SCTP packet and discard it, do not process 4137 * any further chunks within it. 4138 * 4139 * 01 - Stop processing this SCTP packet and discard it, do not process 4140 * any further chunks within it, and report the unrecognized 4141 * chunk in an 'Unrecognized Chunk Type'. 4142 * 4143 * 10 - Skip this chunk and continue processing. 4144 * 4145 * 11 - Skip this chunk and continue processing, but report in an ERROR 4146 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4147 * 4148 * The return value is the disposition of the chunk. 4149 */ 4150 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4151 const struct sctp_endpoint *ep, 4152 const struct sctp_association *asoc, 4153 const sctp_subtype_t type, 4154 void *arg, 4155 sctp_cmd_seq_t *commands) 4156 { 4157 struct sctp_chunk *unk_chunk = arg; 4158 struct sctp_chunk *err_chunk; 4159 sctp_chunkhdr_t *hdr; 4160 4161 SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); 4162 4163 if (!sctp_vtag_verify(unk_chunk, asoc)) 4164 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4165 4166 /* Make sure that the chunk has a valid length. 4167 * Since we don't know the chunk type, we use a general 4168 * chunkhdr structure to make a comparison. 4169 */ 4170 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4171 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4172 commands); 4173 4174 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4175 case SCTP_CID_ACTION_DISCARD: 4176 /* Discard the packet. */ 4177 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4178 break; 4179 case SCTP_CID_ACTION_DISCARD_ERR: 4180 /* Generate an ERROR chunk as response. */ 4181 hdr = unk_chunk->chunk_hdr; 4182 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4183 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4184 WORD_ROUND(ntohs(hdr->length)), 4185 0); 4186 if (err_chunk) { 4187 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4188 SCTP_CHUNK(err_chunk)); 4189 } 4190 4191 /* Discard the packet. */ 4192 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4193 return SCTP_DISPOSITION_CONSUME; 4194 break; 4195 case SCTP_CID_ACTION_SKIP: 4196 /* Skip the chunk. */ 4197 return SCTP_DISPOSITION_DISCARD; 4198 break; 4199 case SCTP_CID_ACTION_SKIP_ERR: 4200 /* Generate an ERROR chunk as response. */ 4201 hdr = unk_chunk->chunk_hdr; 4202 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4203 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4204 WORD_ROUND(ntohs(hdr->length)), 4205 0); 4206 if (err_chunk) { 4207 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4208 SCTP_CHUNK(err_chunk)); 4209 } 4210 /* Skip the chunk. */ 4211 return SCTP_DISPOSITION_CONSUME; 4212 break; 4213 default: 4214 break; 4215 } 4216 4217 return SCTP_DISPOSITION_DISCARD; 4218 } 4219 4220 /* 4221 * Discard the chunk. 4222 * 4223 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4224 * [Too numerous to mention...] 4225 * Verification Tag: No verification needed. 4226 * Inputs 4227 * (endpoint, asoc, chunk) 4228 * 4229 * Outputs 4230 * (asoc, reply_msg, msg_up, timers, counters) 4231 * 4232 * The return value is the disposition of the chunk. 4233 */ 4234 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4235 const struct sctp_endpoint *ep, 4236 const struct sctp_association *asoc, 4237 const sctp_subtype_t type, 4238 void *arg, 4239 sctp_cmd_seq_t *commands) 4240 { 4241 struct sctp_chunk *chunk = arg; 4242 4243 /* Make sure that the chunk has a valid length. 4244 * Since we don't know the chunk type, we use a general 4245 * chunkhdr structure to make a comparison. 4246 */ 4247 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4248 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4249 commands); 4250 4251 SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); 4252 return SCTP_DISPOSITION_DISCARD; 4253 } 4254 4255 /* 4256 * Discard the whole packet. 4257 * 4258 * Section: 8.4 2) 4259 * 4260 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4261 * silently discard the OOTB packet and take no further action. 4262 * 4263 * Verification Tag: No verification necessary 4264 * 4265 * Inputs 4266 * (endpoint, asoc, chunk) 4267 * 4268 * Outputs 4269 * (asoc, reply_msg, msg_up, timers, counters) 4270 * 4271 * The return value is the disposition of the chunk. 4272 */ 4273 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4274 const struct sctp_endpoint *ep, 4275 const struct sctp_association *asoc, 4276 const sctp_subtype_t type, 4277 void *arg, 4278 sctp_cmd_seq_t *commands) 4279 { 4280 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4281 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4282 4283 return SCTP_DISPOSITION_CONSUME; 4284 } 4285 4286 4287 /* 4288 * The other end is violating protocol. 4289 * 4290 * Section: Not specified 4291 * Verification Tag: Not specified 4292 * Inputs 4293 * (endpoint, asoc, chunk) 4294 * 4295 * Outputs 4296 * (asoc, reply_msg, msg_up, timers, counters) 4297 * 4298 * We simply tag the chunk as a violation. The state machine will log 4299 * the violation and continue. 4300 */ 4301 sctp_disposition_t sctp_sf_violation(struct net *net, 4302 const struct sctp_endpoint *ep, 4303 const struct sctp_association *asoc, 4304 const sctp_subtype_t type, 4305 void *arg, 4306 sctp_cmd_seq_t *commands) 4307 { 4308 struct sctp_chunk *chunk = arg; 4309 4310 /* Make sure that the chunk has a valid length. */ 4311 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4312 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4313 commands); 4314 4315 return SCTP_DISPOSITION_VIOLATION; 4316 } 4317 4318 /* 4319 * Common function to handle a protocol violation. 4320 */ 4321 static sctp_disposition_t sctp_sf_abort_violation( 4322 struct net *net, 4323 const struct sctp_endpoint *ep, 4324 const struct sctp_association *asoc, 4325 void *arg, 4326 sctp_cmd_seq_t *commands, 4327 const __u8 *payload, 4328 const size_t paylen) 4329 { 4330 struct sctp_packet *packet = NULL; 4331 struct sctp_chunk *chunk = arg; 4332 struct sctp_chunk *abort = NULL; 4333 4334 /* SCTP-AUTH, Section 6.3: 4335 * It should be noted that if the receiver wants to tear 4336 * down an association in an authenticated way only, the 4337 * handling of malformed packets should not result in 4338 * tearing down the association. 4339 * 4340 * This means that if we only want to abort associations 4341 * in an authenticated way (i.e AUTH+ABORT), then we 4342 * can't destroy this association just because the packet 4343 * was malformed. 4344 */ 4345 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4346 goto discard; 4347 4348 /* Make the abort chunk. */ 4349 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4350 if (!abort) 4351 goto nomem; 4352 4353 if (asoc) { 4354 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4355 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4356 !asoc->peer.i.init_tag) { 4357 sctp_initack_chunk_t *initack; 4358 4359 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4360 if (!sctp_chunk_length_valid(chunk, 4361 sizeof(sctp_initack_chunk_t))) 4362 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4363 else { 4364 unsigned int inittag; 4365 4366 inittag = ntohl(initack->init_hdr.init_tag); 4367 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4368 SCTP_U32(inittag)); 4369 } 4370 } 4371 4372 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4373 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4374 4375 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4376 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4377 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4378 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4379 SCTP_ERROR(ECONNREFUSED)); 4380 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4381 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4382 } else { 4383 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4384 SCTP_ERROR(ECONNABORTED)); 4385 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4386 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4387 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4388 } 4389 } else { 4390 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4391 4392 if (!packet) 4393 goto nomem_pkt; 4394 4395 if (sctp_test_T_bit(abort)) 4396 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4397 4398 abort->skb->sk = ep->base.sk; 4399 4400 sctp_packet_append_chunk(packet, abort); 4401 4402 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4403 SCTP_PACKET(packet)); 4404 4405 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4406 } 4407 4408 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4409 4410 discard: 4411 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4412 return SCTP_DISPOSITION_ABORT; 4413 4414 nomem_pkt: 4415 sctp_chunk_free(abort); 4416 nomem: 4417 return SCTP_DISPOSITION_NOMEM; 4418 } 4419 4420 /* 4421 * Handle a protocol violation when the chunk length is invalid. 4422 * "Invalid" length is identified as smaller than the minimal length a 4423 * given chunk can be. For example, a SACK chunk has invalid length 4424 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4425 * 4426 * We inform the other end by sending an ABORT with a Protocol Violation 4427 * error code. 4428 * 4429 * Section: Not specified 4430 * Verification Tag: Nothing to do 4431 * Inputs 4432 * (endpoint, asoc, chunk) 4433 * 4434 * Outputs 4435 * (reply_msg, msg_up, counters) 4436 * 4437 * Generate an ABORT chunk and terminate the association. 4438 */ 4439 static sctp_disposition_t sctp_sf_violation_chunklen( 4440 struct net *net, 4441 const struct sctp_endpoint *ep, 4442 const struct sctp_association *asoc, 4443 const sctp_subtype_t type, 4444 void *arg, 4445 sctp_cmd_seq_t *commands) 4446 { 4447 static const char err_str[]="The following chunk had invalid length:"; 4448 4449 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4450 sizeof(err_str)); 4451 } 4452 4453 /* 4454 * Handle a protocol violation when the parameter length is invalid. 4455 * If the length is smaller than the minimum length of a given parameter, 4456 * or accumulated length in multi parameters exceeds the end of the chunk, 4457 * the length is considered as invalid. 4458 */ 4459 static sctp_disposition_t sctp_sf_violation_paramlen( 4460 struct net *net, 4461 const struct sctp_endpoint *ep, 4462 const struct sctp_association *asoc, 4463 const sctp_subtype_t type, 4464 void *arg, void *ext, 4465 sctp_cmd_seq_t *commands) 4466 { 4467 struct sctp_chunk *chunk = arg; 4468 struct sctp_paramhdr *param = ext; 4469 struct sctp_chunk *abort = NULL; 4470 4471 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4472 goto discard; 4473 4474 /* Make the abort chunk. */ 4475 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4476 if (!abort) 4477 goto nomem; 4478 4479 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4480 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4481 4482 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4483 SCTP_ERROR(ECONNABORTED)); 4484 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4485 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4486 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4487 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4488 4489 discard: 4490 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4491 return SCTP_DISPOSITION_ABORT; 4492 nomem: 4493 return SCTP_DISPOSITION_NOMEM; 4494 } 4495 4496 /* Handle a protocol violation when the peer trying to advance the 4497 * cumulative tsn ack to a point beyond the max tsn currently sent. 4498 * 4499 * We inform the other end by sending an ABORT with a Protocol Violation 4500 * error code. 4501 */ 4502 static sctp_disposition_t sctp_sf_violation_ctsn( 4503 struct net *net, 4504 const struct sctp_endpoint *ep, 4505 const struct sctp_association *asoc, 4506 const sctp_subtype_t type, 4507 void *arg, 4508 sctp_cmd_seq_t *commands) 4509 { 4510 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4511 4512 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4513 sizeof(err_str)); 4514 } 4515 4516 /* Handle protocol violation of an invalid chunk bundling. For example, 4517 * when we have an association and we receive bundled INIT-ACK, or 4518 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4519 * statement from the specs. Additionally, there might be an attacker 4520 * on the path and we may not want to continue this communication. 4521 */ 4522 static sctp_disposition_t sctp_sf_violation_chunk( 4523 struct net *net, 4524 const struct sctp_endpoint *ep, 4525 const struct sctp_association *asoc, 4526 const sctp_subtype_t type, 4527 void *arg, 4528 sctp_cmd_seq_t *commands) 4529 { 4530 static const char err_str[]="The following chunk violates protocol:"; 4531 4532 if (!asoc) 4533 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4534 4535 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4536 sizeof(err_str)); 4537 } 4538 /*************************************************************************** 4539 * These are the state functions for handling primitive (Section 10) events. 4540 ***************************************************************************/ 4541 /* 4542 * sctp_sf_do_prm_asoc 4543 * 4544 * Section: 10.1 ULP-to-SCTP 4545 * B) Associate 4546 * 4547 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4548 * outbound stream count) 4549 * -> association id [,destination transport addr list] [,outbound stream 4550 * count] 4551 * 4552 * This primitive allows the upper layer to initiate an association to a 4553 * specific peer endpoint. 4554 * 4555 * The peer endpoint shall be specified by one of the transport addresses 4556 * which defines the endpoint (see Section 1.4). If the local SCTP 4557 * instance has not been initialized, the ASSOCIATE is considered an 4558 * error. 4559 * [This is not relevant for the kernel implementation since we do all 4560 * initialization at boot time. It we hadn't initialized we wouldn't 4561 * get anywhere near this code.] 4562 * 4563 * An association id, which is a local handle to the SCTP association, 4564 * will be returned on successful establishment of the association. If 4565 * SCTP is not able to open an SCTP association with the peer endpoint, 4566 * an error is returned. 4567 * [In the kernel implementation, the struct sctp_association needs to 4568 * be created BEFORE causing this primitive to run.] 4569 * 4570 * Other association parameters may be returned, including the 4571 * complete destination transport addresses of the peer as well as the 4572 * outbound stream count of the local endpoint. One of the transport 4573 * address from the returned destination addresses will be selected by 4574 * the local endpoint as default primary path for sending SCTP packets 4575 * to this peer. The returned "destination transport addr list" can 4576 * be used by the ULP to change the default primary path or to force 4577 * sending a packet to a specific transport address. [All of this 4578 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4579 * function.] 4580 * 4581 * Mandatory attributes: 4582 * 4583 * o local SCTP instance name - obtained from the INITIALIZE operation. 4584 * [This is the argument asoc.] 4585 * o destination transport addr - specified as one of the transport 4586 * addresses of the peer endpoint with which the association is to be 4587 * established. 4588 * [This is asoc->peer.active_path.] 4589 * o outbound stream count - the number of outbound streams the ULP 4590 * would like to open towards this peer endpoint. 4591 * [BUG: This is not currently implemented.] 4592 * Optional attributes: 4593 * 4594 * None. 4595 * 4596 * The return value is a disposition. 4597 */ 4598 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4599 const struct sctp_endpoint *ep, 4600 const struct sctp_association *asoc, 4601 const sctp_subtype_t type, 4602 void *arg, 4603 sctp_cmd_seq_t *commands) 4604 { 4605 struct sctp_chunk *repl; 4606 struct sctp_association* my_asoc; 4607 4608 /* The comment below says that we enter COOKIE-WAIT AFTER 4609 * sending the INIT, but that doesn't actually work in our 4610 * implementation... 4611 */ 4612 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4613 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4614 4615 /* RFC 2960 5.1 Normal Establishment of an Association 4616 * 4617 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4618 * must provide its Verification Tag (Tag_A) in the Initiate 4619 * Tag field. Tag_A SHOULD be a random number in the range of 4620 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4621 */ 4622 4623 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4624 if (!repl) 4625 goto nomem; 4626 4627 /* Cast away the const modifier, as we want to just 4628 * rerun it through as a sideffect. 4629 */ 4630 my_asoc = (struct sctp_association *)asoc; 4631 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4632 4633 /* Choose transport for INIT. */ 4634 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4635 SCTP_CHUNK(repl)); 4636 4637 /* After sending the INIT, "A" starts the T1-init timer and 4638 * enters the COOKIE-WAIT state. 4639 */ 4640 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4641 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4642 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4643 return SCTP_DISPOSITION_CONSUME; 4644 4645 nomem: 4646 return SCTP_DISPOSITION_NOMEM; 4647 } 4648 4649 /* 4650 * Process the SEND primitive. 4651 * 4652 * Section: 10.1 ULP-to-SCTP 4653 * E) Send 4654 * 4655 * Format: SEND(association id, buffer address, byte count [,context] 4656 * [,stream id] [,life time] [,destination transport address] 4657 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4658 * -> result 4659 * 4660 * This is the main method to send user data via SCTP. 4661 * 4662 * Mandatory attributes: 4663 * 4664 * o association id - local handle to the SCTP association 4665 * 4666 * o buffer address - the location where the user message to be 4667 * transmitted is stored; 4668 * 4669 * o byte count - The size of the user data in number of bytes; 4670 * 4671 * Optional attributes: 4672 * 4673 * o context - an optional 32 bit integer that will be carried in the 4674 * sending failure notification to the ULP if the transportation of 4675 * this User Message fails. 4676 * 4677 * o stream id - to indicate which stream to send the data on. If not 4678 * specified, stream 0 will be used. 4679 * 4680 * o life time - specifies the life time of the user data. The user data 4681 * will not be sent by SCTP after the life time expires. This 4682 * parameter can be used to avoid efforts to transmit stale 4683 * user messages. SCTP notifies the ULP if the data cannot be 4684 * initiated to transport (i.e. sent to the destination via SCTP's 4685 * send primitive) within the life time variable. However, the 4686 * user data will be transmitted if SCTP has attempted to transmit a 4687 * chunk before the life time expired. 4688 * 4689 * o destination transport address - specified as one of the destination 4690 * transport addresses of the peer endpoint to which this packet 4691 * should be sent. Whenever possible, SCTP should use this destination 4692 * transport address for sending the packets, instead of the current 4693 * primary path. 4694 * 4695 * o unorder flag - this flag, if present, indicates that the user 4696 * would like the data delivered in an unordered fashion to the peer 4697 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4698 * message). 4699 * 4700 * o no-bundle flag - instructs SCTP not to bundle this user data with 4701 * other outbound DATA chunks. SCTP MAY still bundle even when 4702 * this flag is present, when faced with network congestion. 4703 * 4704 * o payload protocol-id - A 32 bit unsigned integer that is to be 4705 * passed to the peer indicating the type of payload protocol data 4706 * being transmitted. This value is passed as opaque data by SCTP. 4707 * 4708 * The return value is the disposition. 4709 */ 4710 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4711 const struct sctp_endpoint *ep, 4712 const struct sctp_association *asoc, 4713 const sctp_subtype_t type, 4714 void *arg, 4715 sctp_cmd_seq_t *commands) 4716 { 4717 struct sctp_datamsg *msg = arg; 4718 4719 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4720 return SCTP_DISPOSITION_CONSUME; 4721 } 4722 4723 /* 4724 * Process the SHUTDOWN primitive. 4725 * 4726 * Section: 10.1: 4727 * C) Shutdown 4728 * 4729 * Format: SHUTDOWN(association id) 4730 * -> result 4731 * 4732 * Gracefully closes an association. Any locally queued user data 4733 * will be delivered to the peer. The association will be terminated only 4734 * after the peer acknowledges all the SCTP packets sent. A success code 4735 * will be returned on successful termination of the association. If 4736 * attempting to terminate the association results in a failure, an error 4737 * code shall be returned. 4738 * 4739 * Mandatory attributes: 4740 * 4741 * o association id - local handle to the SCTP association 4742 * 4743 * Optional attributes: 4744 * 4745 * None. 4746 * 4747 * The return value is the disposition. 4748 */ 4749 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4750 struct net *net, 4751 const struct sctp_endpoint *ep, 4752 const struct sctp_association *asoc, 4753 const sctp_subtype_t type, 4754 void *arg, 4755 sctp_cmd_seq_t *commands) 4756 { 4757 int disposition; 4758 4759 /* From 9.2 Shutdown of an Association 4760 * Upon receipt of the SHUTDOWN primitive from its upper 4761 * layer, the endpoint enters SHUTDOWN-PENDING state and 4762 * remains there until all outstanding data has been 4763 * acknowledged by its peer. The endpoint accepts no new data 4764 * from its upper layer, but retransmits data to the far end 4765 * if necessary to fill gaps. 4766 */ 4767 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4768 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4769 4770 disposition = SCTP_DISPOSITION_CONSUME; 4771 if (sctp_outq_is_empty(&asoc->outqueue)) { 4772 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4773 arg, commands); 4774 } 4775 return disposition; 4776 } 4777 4778 /* 4779 * Process the ABORT primitive. 4780 * 4781 * Section: 10.1: 4782 * C) Abort 4783 * 4784 * Format: Abort(association id [, cause code]) 4785 * -> result 4786 * 4787 * Ungracefully closes an association. Any locally queued user data 4788 * will be discarded and an ABORT chunk is sent to the peer. A success code 4789 * will be returned on successful abortion of the association. If 4790 * attempting to abort the association results in a failure, an error 4791 * code shall be returned. 4792 * 4793 * Mandatory attributes: 4794 * 4795 * o association id - local handle to the SCTP association 4796 * 4797 * Optional attributes: 4798 * 4799 * o cause code - reason of the abort to be passed to the peer 4800 * 4801 * None. 4802 * 4803 * The return value is the disposition. 4804 */ 4805 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4806 struct net *net, 4807 const struct sctp_endpoint *ep, 4808 const struct sctp_association *asoc, 4809 const sctp_subtype_t type, 4810 void *arg, 4811 sctp_cmd_seq_t *commands) 4812 { 4813 /* From 9.1 Abort of an Association 4814 * Upon receipt of the ABORT primitive from its upper 4815 * layer, the endpoint enters CLOSED state and 4816 * discard all outstanding data has been 4817 * acknowledged by its peer. The endpoint accepts no new data 4818 * from its upper layer, but retransmits data to the far end 4819 * if necessary to fill gaps. 4820 */ 4821 struct sctp_chunk *abort = arg; 4822 sctp_disposition_t retval; 4823 4824 retval = SCTP_DISPOSITION_CONSUME; 4825 4826 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4827 4828 /* Even if we can't send the ABORT due to low memory delete the 4829 * TCB. This is a departure from our typical NOMEM handling. 4830 */ 4831 4832 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4833 SCTP_ERROR(ECONNABORTED)); 4834 /* Delete the established association. */ 4835 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4836 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4837 4838 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4839 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4840 4841 return retval; 4842 } 4843 4844 /* We tried an illegal operation on an association which is closed. */ 4845 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4846 const struct sctp_endpoint *ep, 4847 const struct sctp_association *asoc, 4848 const sctp_subtype_t type, 4849 void *arg, 4850 sctp_cmd_seq_t *commands) 4851 { 4852 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4853 return SCTP_DISPOSITION_CONSUME; 4854 } 4855 4856 /* We tried an illegal operation on an association which is shutting 4857 * down. 4858 */ 4859 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4860 const struct sctp_endpoint *ep, 4861 const struct sctp_association *asoc, 4862 const sctp_subtype_t type, 4863 void *arg, 4864 sctp_cmd_seq_t *commands) 4865 { 4866 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4867 SCTP_ERROR(-ESHUTDOWN)); 4868 return SCTP_DISPOSITION_CONSUME; 4869 } 4870 4871 /* 4872 * sctp_cookie_wait_prm_shutdown 4873 * 4874 * Section: 4 Note: 2 4875 * Verification Tag: 4876 * Inputs 4877 * (endpoint, asoc) 4878 * 4879 * The RFC does not explicitly address this issue, but is the route through the 4880 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4881 * 4882 * Outputs 4883 * (timers) 4884 */ 4885 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4886 struct net *net, 4887 const struct sctp_endpoint *ep, 4888 const struct sctp_association *asoc, 4889 const sctp_subtype_t type, 4890 void *arg, 4891 sctp_cmd_seq_t *commands) 4892 { 4893 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4894 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4895 4896 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4897 SCTP_STATE(SCTP_STATE_CLOSED)); 4898 4899 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4900 4901 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4902 4903 return SCTP_DISPOSITION_DELETE_TCB; 4904 } 4905 4906 /* 4907 * sctp_cookie_echoed_prm_shutdown 4908 * 4909 * Section: 4 Note: 2 4910 * Verification Tag: 4911 * Inputs 4912 * (endpoint, asoc) 4913 * 4914 * The RFC does not explcitly address this issue, but is the route through the 4915 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4916 * 4917 * Outputs 4918 * (timers) 4919 */ 4920 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4921 struct net *net, 4922 const struct sctp_endpoint *ep, 4923 const struct sctp_association *asoc, 4924 const sctp_subtype_t type, 4925 void *arg, sctp_cmd_seq_t *commands) 4926 { 4927 /* There is a single T1 timer, so we should be able to use 4928 * common function with the COOKIE-WAIT state. 4929 */ 4930 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 4931 } 4932 4933 /* 4934 * sctp_sf_cookie_wait_prm_abort 4935 * 4936 * Section: 4 Note: 2 4937 * Verification Tag: 4938 * Inputs 4939 * (endpoint, asoc) 4940 * 4941 * The RFC does not explicitly address this issue, but is the route through the 4942 * state table when someone issues an abort while in COOKIE_WAIT state. 4943 * 4944 * Outputs 4945 * (timers) 4946 */ 4947 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4948 struct net *net, 4949 const struct sctp_endpoint *ep, 4950 const struct sctp_association *asoc, 4951 const sctp_subtype_t type, 4952 void *arg, 4953 sctp_cmd_seq_t *commands) 4954 { 4955 struct sctp_chunk *abort = arg; 4956 sctp_disposition_t retval; 4957 4958 /* Stop T1-init timer */ 4959 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4960 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4961 retval = SCTP_DISPOSITION_CONSUME; 4962 4963 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4964 4965 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4966 SCTP_STATE(SCTP_STATE_CLOSED)); 4967 4968 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4969 4970 /* Even if we can't send the ABORT due to low memory delete the 4971 * TCB. This is a departure from our typical NOMEM handling. 4972 */ 4973 4974 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4975 SCTP_ERROR(ECONNREFUSED)); 4976 /* Delete the established association. */ 4977 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4978 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4979 4980 return retval; 4981 } 4982 4983 /* 4984 * sctp_sf_cookie_echoed_prm_abort 4985 * 4986 * Section: 4 Note: 3 4987 * Verification Tag: 4988 * Inputs 4989 * (endpoint, asoc) 4990 * 4991 * The RFC does not explcitly address this issue, but is the route through the 4992 * state table when someone issues an abort while in COOKIE_ECHOED state. 4993 * 4994 * Outputs 4995 * (timers) 4996 */ 4997 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 4998 struct net *net, 4999 const struct sctp_endpoint *ep, 5000 const struct sctp_association *asoc, 5001 const sctp_subtype_t type, 5002 void *arg, 5003 sctp_cmd_seq_t *commands) 5004 { 5005 /* There is a single T1 timer, so we should be able to use 5006 * common function with the COOKIE-WAIT state. 5007 */ 5008 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5009 } 5010 5011 /* 5012 * sctp_sf_shutdown_pending_prm_abort 5013 * 5014 * Inputs 5015 * (endpoint, asoc) 5016 * 5017 * The RFC does not explicitly address this issue, but is the route through the 5018 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5019 * 5020 * Outputs 5021 * (timers) 5022 */ 5023 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5024 struct net *net, 5025 const struct sctp_endpoint *ep, 5026 const struct sctp_association *asoc, 5027 const sctp_subtype_t type, 5028 void *arg, 5029 sctp_cmd_seq_t *commands) 5030 { 5031 /* Stop the T5-shutdown guard timer. */ 5032 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5033 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5034 5035 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5036 } 5037 5038 /* 5039 * sctp_sf_shutdown_sent_prm_abort 5040 * 5041 * Inputs 5042 * (endpoint, asoc) 5043 * 5044 * The RFC does not explicitly address this issue, but is the route through the 5045 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5046 * 5047 * Outputs 5048 * (timers) 5049 */ 5050 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5051 struct net *net, 5052 const struct sctp_endpoint *ep, 5053 const struct sctp_association *asoc, 5054 const sctp_subtype_t type, 5055 void *arg, 5056 sctp_cmd_seq_t *commands) 5057 { 5058 /* Stop the T2-shutdown timer. */ 5059 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5060 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5061 5062 /* Stop the T5-shutdown guard timer. */ 5063 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5064 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5065 5066 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5067 } 5068 5069 /* 5070 * sctp_sf_cookie_echoed_prm_abort 5071 * 5072 * Inputs 5073 * (endpoint, asoc) 5074 * 5075 * The RFC does not explcitly address this issue, but is the route through the 5076 * state table when someone issues an abort while in COOKIE_ECHOED state. 5077 * 5078 * Outputs 5079 * (timers) 5080 */ 5081 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5082 struct net *net, 5083 const struct sctp_endpoint *ep, 5084 const struct sctp_association *asoc, 5085 const sctp_subtype_t type, 5086 void *arg, 5087 sctp_cmd_seq_t *commands) 5088 { 5089 /* The same T2 timer, so we should be able to use 5090 * common function with the SHUTDOWN-SENT state. 5091 */ 5092 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5093 } 5094 5095 /* 5096 * Process the REQUESTHEARTBEAT primitive 5097 * 5098 * 10.1 ULP-to-SCTP 5099 * J) Request Heartbeat 5100 * 5101 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5102 * 5103 * -> result 5104 * 5105 * Instructs the local endpoint to perform a HeartBeat on the specified 5106 * destination transport address of the given association. The returned 5107 * result should indicate whether the transmission of the HEARTBEAT 5108 * chunk to the destination address is successful. 5109 * 5110 * Mandatory attributes: 5111 * 5112 * o association id - local handle to the SCTP association 5113 * 5114 * o destination transport address - the transport address of the 5115 * association on which a heartbeat should be issued. 5116 */ 5117 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5118 struct net *net, 5119 const struct sctp_endpoint *ep, 5120 const struct sctp_association *asoc, 5121 const sctp_subtype_t type, 5122 void *arg, 5123 sctp_cmd_seq_t *commands) 5124 { 5125 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5126 (struct sctp_transport *)arg, commands)) 5127 return SCTP_DISPOSITION_NOMEM; 5128 5129 /* 5130 * RFC 2960 (bis), section 8.3 5131 * 5132 * D) Request an on-demand HEARTBEAT on a specific destination 5133 * transport address of a given association. 5134 * 5135 * The endpoint should increment the respective error counter of 5136 * the destination transport address each time a HEARTBEAT is sent 5137 * to that address and not acknowledged within one RTO. 5138 * 5139 */ 5140 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5141 SCTP_TRANSPORT(arg)); 5142 return SCTP_DISPOSITION_CONSUME; 5143 } 5144 5145 /* 5146 * ADDIP Section 4.1 ASCONF Chunk Procedures 5147 * When an endpoint has an ASCONF signaled change to be sent to the 5148 * remote endpoint it should do A1 to A9 5149 */ 5150 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5151 const struct sctp_endpoint *ep, 5152 const struct sctp_association *asoc, 5153 const sctp_subtype_t type, 5154 void *arg, 5155 sctp_cmd_seq_t *commands) 5156 { 5157 struct sctp_chunk *chunk = arg; 5158 5159 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5160 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5161 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5162 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5163 return SCTP_DISPOSITION_CONSUME; 5164 } 5165 5166 /* 5167 * Ignore the primitive event 5168 * 5169 * The return value is the disposition of the primitive. 5170 */ 5171 sctp_disposition_t sctp_sf_ignore_primitive( 5172 struct net *net, 5173 const struct sctp_endpoint *ep, 5174 const struct sctp_association *asoc, 5175 const sctp_subtype_t type, 5176 void *arg, 5177 sctp_cmd_seq_t *commands) 5178 { 5179 SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); 5180 return SCTP_DISPOSITION_DISCARD; 5181 } 5182 5183 /*************************************************************************** 5184 * These are the state functions for the OTHER events. 5185 ***************************************************************************/ 5186 5187 /* 5188 * When the SCTP stack has no more user data to send or retransmit, this 5189 * notification is given to the user. Also, at the time when a user app 5190 * subscribes to this event, if there is no data to be sent or 5191 * retransmit, the stack will immediately send up this notification. 5192 */ 5193 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5194 struct net *net, 5195 const struct sctp_endpoint *ep, 5196 const struct sctp_association *asoc, 5197 const sctp_subtype_t type, 5198 void *arg, 5199 sctp_cmd_seq_t *commands) 5200 { 5201 struct sctp_ulpevent *event; 5202 5203 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5204 if (!event) 5205 return SCTP_DISPOSITION_NOMEM; 5206 5207 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5208 5209 return SCTP_DISPOSITION_CONSUME; 5210 } 5211 5212 /* 5213 * Start the shutdown negotiation. 5214 * 5215 * From Section 9.2: 5216 * Once all its outstanding data has been acknowledged, the endpoint 5217 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5218 * TSN Ack field the last sequential TSN it has received from the peer. 5219 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5220 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5221 * with the updated last sequential TSN received from its peer. 5222 * 5223 * The return value is the disposition. 5224 */ 5225 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5226 struct net *net, 5227 const struct sctp_endpoint *ep, 5228 const struct sctp_association *asoc, 5229 const sctp_subtype_t type, 5230 void *arg, 5231 sctp_cmd_seq_t *commands) 5232 { 5233 struct sctp_chunk *reply; 5234 5235 /* Once all its outstanding data has been acknowledged, the 5236 * endpoint shall send a SHUTDOWN chunk to its peer including 5237 * in the Cumulative TSN Ack field the last sequential TSN it 5238 * has received from the peer. 5239 */ 5240 reply = sctp_make_shutdown(asoc, NULL); 5241 if (!reply) 5242 goto nomem; 5243 5244 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5245 * T2-shutdown timer. 5246 */ 5247 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5248 5249 /* It shall then start the T2-shutdown timer */ 5250 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5251 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5252 5253 /* RFC 4960 Section 9.2 5254 * The sender of the SHUTDOWN MAY also start an overall guard timer 5255 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5256 */ 5257 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5258 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5259 5260 if (asoc->autoclose) 5261 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5262 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5263 5264 /* and enter the SHUTDOWN-SENT state. */ 5265 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5266 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5267 5268 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5269 * 5270 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5271 * or SHUTDOWN-ACK. 5272 */ 5273 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5274 5275 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5276 5277 return SCTP_DISPOSITION_CONSUME; 5278 5279 nomem: 5280 return SCTP_DISPOSITION_NOMEM; 5281 } 5282 5283 /* 5284 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5285 * 5286 * From Section 9.2: 5287 * 5288 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5289 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5290 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5291 * endpoint must re-send the SHUTDOWN ACK. 5292 * 5293 * The return value is the disposition. 5294 */ 5295 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5296 struct net *net, 5297 const struct sctp_endpoint *ep, 5298 const struct sctp_association *asoc, 5299 const sctp_subtype_t type, 5300 void *arg, 5301 sctp_cmd_seq_t *commands) 5302 { 5303 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5304 struct sctp_chunk *reply; 5305 5306 /* There are 2 ways of getting here: 5307 * 1) called in response to a SHUTDOWN chunk 5308 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5309 * 5310 * For the case (2), the arg parameter is set to NULL. We need 5311 * to check that we have a chunk before accessing it's fields. 5312 */ 5313 if (chunk) { 5314 if (!sctp_vtag_verify(chunk, asoc)) 5315 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5316 5317 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5318 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5319 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5320 commands); 5321 } 5322 5323 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5324 * shall send a SHUTDOWN ACK ... 5325 */ 5326 reply = sctp_make_shutdown_ack(asoc, chunk); 5327 if (!reply) 5328 goto nomem; 5329 5330 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5331 * the T2-shutdown timer. 5332 */ 5333 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5334 5335 /* and start/restart a T2-shutdown timer of its own, */ 5336 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5337 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5338 5339 if (asoc->autoclose) 5340 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5341 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5342 5343 /* Enter the SHUTDOWN-ACK-SENT state. */ 5344 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5345 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5346 5347 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5348 * 5349 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5350 * or SHUTDOWN-ACK. 5351 */ 5352 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5353 5354 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5355 5356 return SCTP_DISPOSITION_CONSUME; 5357 5358 nomem: 5359 return SCTP_DISPOSITION_NOMEM; 5360 } 5361 5362 /* 5363 * Ignore the event defined as other 5364 * 5365 * The return value is the disposition of the event. 5366 */ 5367 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5368 const struct sctp_endpoint *ep, 5369 const struct sctp_association *asoc, 5370 const sctp_subtype_t type, 5371 void *arg, 5372 sctp_cmd_seq_t *commands) 5373 { 5374 SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); 5375 return SCTP_DISPOSITION_DISCARD; 5376 } 5377 5378 /************************************************************ 5379 * These are the state functions for handling timeout events. 5380 ************************************************************/ 5381 5382 /* 5383 * RTX Timeout 5384 * 5385 * Section: 6.3.3 Handle T3-rtx Expiration 5386 * 5387 * Whenever the retransmission timer T3-rtx expires for a destination 5388 * address, do the following: 5389 * [See below] 5390 * 5391 * The return value is the disposition of the chunk. 5392 */ 5393 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5394 const struct sctp_endpoint *ep, 5395 const struct sctp_association *asoc, 5396 const sctp_subtype_t type, 5397 void *arg, 5398 sctp_cmd_seq_t *commands) 5399 { 5400 struct sctp_transport *transport = arg; 5401 5402 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5403 5404 if (asoc->overall_error_count >= asoc->max_retrans) { 5405 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5406 /* 5407 * We are here likely because the receiver had its rwnd 5408 * closed for a while and we have not been able to 5409 * transmit the locally queued data within the maximum 5410 * retransmission attempts limit. Start the T5 5411 * shutdown guard timer to give the receiver one last 5412 * chance and some additional time to recover before 5413 * aborting. 5414 */ 5415 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5416 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5417 } else { 5418 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5419 SCTP_ERROR(ETIMEDOUT)); 5420 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5421 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5422 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5423 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5424 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5425 return SCTP_DISPOSITION_DELETE_TCB; 5426 } 5427 } 5428 5429 /* E1) For the destination address for which the timer 5430 * expires, adjust its ssthresh with rules defined in Section 5431 * 7.2.3 and set the cwnd <- MTU. 5432 */ 5433 5434 /* E2) For the destination address for which the timer 5435 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5436 * maximum value discussed in rule C7 above (RTO.max) may be 5437 * used to provide an upper bound to this doubling operation. 5438 */ 5439 5440 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5441 * outstanding DATA chunks for the address for which the 5442 * T3-rtx has expired will fit into a single packet, subject 5443 * to the MTU constraint for the path corresponding to the 5444 * destination transport address to which the retransmission 5445 * is being sent (this may be different from the address for 5446 * which the timer expires [see Section 6.4]). Call this 5447 * value K. Bundle and retransmit those K DATA chunks in a 5448 * single packet to the destination endpoint. 5449 * 5450 * Note: Any DATA chunks that were sent to the address for 5451 * which the T3-rtx timer expired but did not fit in one MTU 5452 * (rule E3 above), should be marked for retransmission and 5453 * sent as soon as cwnd allows (normally when a SACK arrives). 5454 */ 5455 5456 /* Do some failure management (Section 8.2). */ 5457 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5458 5459 /* NB: Rules E4 and F1 are implicit in R1. */ 5460 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5461 5462 return SCTP_DISPOSITION_CONSUME; 5463 } 5464 5465 /* 5466 * Generate delayed SACK on timeout 5467 * 5468 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5469 * 5470 * The guidelines on delayed acknowledgement algorithm specified in 5471 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5472 * acknowledgement SHOULD be generated for at least every second packet 5473 * (not every second DATA chunk) received, and SHOULD be generated 5474 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5475 * some situations it may be beneficial for an SCTP transmitter to be 5476 * more conservative than the algorithms detailed in this document 5477 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5478 * the following algorithms allow. 5479 */ 5480 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5481 const struct sctp_endpoint *ep, 5482 const struct sctp_association *asoc, 5483 const sctp_subtype_t type, 5484 void *arg, 5485 sctp_cmd_seq_t *commands) 5486 { 5487 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5488 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5489 return SCTP_DISPOSITION_CONSUME; 5490 } 5491 5492 /* 5493 * sctp_sf_t1_init_timer_expire 5494 * 5495 * Section: 4 Note: 2 5496 * Verification Tag: 5497 * Inputs 5498 * (endpoint, asoc) 5499 * 5500 * RFC 2960 Section 4 Notes 5501 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5502 * and re-start the T1-init timer without changing state. This MUST 5503 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5504 * endpoint MUST abort the initialization process and report the 5505 * error to SCTP user. 5506 * 5507 * Outputs 5508 * (timers, events) 5509 * 5510 */ 5511 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5512 const struct sctp_endpoint *ep, 5513 const struct sctp_association *asoc, 5514 const sctp_subtype_t type, 5515 void *arg, 5516 sctp_cmd_seq_t *commands) 5517 { 5518 struct sctp_chunk *repl = NULL; 5519 struct sctp_bind_addr *bp; 5520 int attempts = asoc->init_err_counter + 1; 5521 5522 SCTP_DEBUG_PRINTK("Timer T1 expired (INIT).\n"); 5523 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5524 5525 if (attempts <= asoc->max_init_attempts) { 5526 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5527 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5528 if (!repl) 5529 return SCTP_DISPOSITION_NOMEM; 5530 5531 /* Choose transport for INIT. */ 5532 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5533 SCTP_CHUNK(repl)); 5534 5535 /* Issue a sideeffect to do the needed accounting. */ 5536 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5537 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5538 5539 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5540 } else { 5541 SCTP_DEBUG_PRINTK("Giving up on INIT, attempts: %d" 5542 " max_init_attempts: %d\n", 5543 attempts, asoc->max_init_attempts); 5544 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5545 SCTP_ERROR(ETIMEDOUT)); 5546 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5547 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5548 return SCTP_DISPOSITION_DELETE_TCB; 5549 } 5550 5551 return SCTP_DISPOSITION_CONSUME; 5552 } 5553 5554 /* 5555 * sctp_sf_t1_cookie_timer_expire 5556 * 5557 * Section: 4 Note: 2 5558 * Verification Tag: 5559 * Inputs 5560 * (endpoint, asoc) 5561 * 5562 * RFC 2960 Section 4 Notes 5563 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5564 * COOKIE ECHO and re-start the T1-cookie timer without changing 5565 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5566 * After that, the endpoint MUST abort the initialization process and 5567 * report the error to SCTP user. 5568 * 5569 * Outputs 5570 * (timers, events) 5571 * 5572 */ 5573 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5574 const struct sctp_endpoint *ep, 5575 const struct sctp_association *asoc, 5576 const sctp_subtype_t type, 5577 void *arg, 5578 sctp_cmd_seq_t *commands) 5579 { 5580 struct sctp_chunk *repl = NULL; 5581 int attempts = asoc->init_err_counter + 1; 5582 5583 SCTP_DEBUG_PRINTK("Timer T1 expired (COOKIE-ECHO).\n"); 5584 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5585 5586 if (attempts <= asoc->max_init_attempts) { 5587 repl = sctp_make_cookie_echo(asoc, NULL); 5588 if (!repl) 5589 return SCTP_DISPOSITION_NOMEM; 5590 5591 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5592 SCTP_CHUNK(repl)); 5593 /* Issue a sideeffect to do the needed accounting. */ 5594 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5595 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5596 5597 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5598 } else { 5599 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5600 SCTP_ERROR(ETIMEDOUT)); 5601 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5602 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5603 return SCTP_DISPOSITION_DELETE_TCB; 5604 } 5605 5606 return SCTP_DISPOSITION_CONSUME; 5607 } 5608 5609 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5610 * with the updated last sequential TSN received from its peer. 5611 * 5612 * An endpoint should limit the number of retransmissions of the 5613 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5614 * If this threshold is exceeded the endpoint should destroy the TCB and 5615 * MUST report the peer endpoint unreachable to the upper layer (and 5616 * thus the association enters the CLOSED state). The reception of any 5617 * packet from its peer (i.e. as the peer sends all of its queued DATA 5618 * chunks) should clear the endpoint's retransmission count and restart 5619 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5620 * all of its queued DATA chunks that have not yet been sent. 5621 */ 5622 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5623 const struct sctp_endpoint *ep, 5624 const struct sctp_association *asoc, 5625 const sctp_subtype_t type, 5626 void *arg, 5627 sctp_cmd_seq_t *commands) 5628 { 5629 struct sctp_chunk *reply = NULL; 5630 5631 SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); 5632 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5633 5634 ((struct sctp_association *)asoc)->shutdown_retries++; 5635 5636 if (asoc->overall_error_count >= asoc->max_retrans) { 5637 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5638 SCTP_ERROR(ETIMEDOUT)); 5639 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5640 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5641 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5642 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5643 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5644 return SCTP_DISPOSITION_DELETE_TCB; 5645 } 5646 5647 switch (asoc->state) { 5648 case SCTP_STATE_SHUTDOWN_SENT: 5649 reply = sctp_make_shutdown(asoc, NULL); 5650 break; 5651 5652 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5653 reply = sctp_make_shutdown_ack(asoc, NULL); 5654 break; 5655 5656 default: 5657 BUG(); 5658 break; 5659 } 5660 5661 if (!reply) 5662 goto nomem; 5663 5664 /* Do some failure management (Section 8.2). 5665 * If we remove the transport an SHUTDOWN was last sent to, don't 5666 * do failure management. 5667 */ 5668 if (asoc->shutdown_last_sent_to) 5669 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5670 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5671 5672 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5673 * the T2-shutdown timer. 5674 */ 5675 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5676 5677 /* Restart the T2-shutdown timer. */ 5678 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5679 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5680 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5681 return SCTP_DISPOSITION_CONSUME; 5682 5683 nomem: 5684 return SCTP_DISPOSITION_NOMEM; 5685 } 5686 5687 /* 5688 * ADDIP Section 4.1 ASCONF CHunk Procedures 5689 * If the T4 RTO timer expires the endpoint should do B1 to B5 5690 */ 5691 sctp_disposition_t sctp_sf_t4_timer_expire( 5692 struct net *net, 5693 const struct sctp_endpoint *ep, 5694 const struct sctp_association *asoc, 5695 const sctp_subtype_t type, 5696 void *arg, 5697 sctp_cmd_seq_t *commands) 5698 { 5699 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5700 struct sctp_transport *transport = chunk->transport; 5701 5702 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5703 5704 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5705 * detection on the appropriate destination address as defined in 5706 * RFC2960 [5] section 8.1 and 8.2. 5707 */ 5708 if (transport) 5709 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5710 SCTP_TRANSPORT(transport)); 5711 5712 /* Reconfig T4 timer and transport. */ 5713 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5714 5715 /* ADDIP 4.1 B2) Increment the association error counters and perform 5716 * endpoint failure detection on the association as defined in 5717 * RFC2960 [5] section 8.1 and 8.2. 5718 * association error counter is incremented in SCTP_CMD_STRIKE. 5719 */ 5720 if (asoc->overall_error_count >= asoc->max_retrans) { 5721 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5722 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5723 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5724 SCTP_ERROR(ETIMEDOUT)); 5725 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5726 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5727 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5728 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5729 return SCTP_DISPOSITION_ABORT; 5730 } 5731 5732 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5733 * the ASCONF chunk was sent by doubling the RTO timer value. 5734 * This is done in SCTP_CMD_STRIKE. 5735 */ 5736 5737 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5738 * choose an alternate destination address (please refer to RFC2960 5739 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5740 * chunk, it MUST be the same (including its serial number) as the last 5741 * ASCONF sent. 5742 */ 5743 sctp_chunk_hold(asoc->addip_last_asconf); 5744 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5745 SCTP_CHUNK(asoc->addip_last_asconf)); 5746 5747 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5748 * destination is selected, then the RTO used will be that of the new 5749 * destination address. 5750 */ 5751 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5752 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5753 5754 return SCTP_DISPOSITION_CONSUME; 5755 } 5756 5757 /* sctpimpguide-05 Section 2.12.2 5758 * The sender of the SHUTDOWN MAY also start an overall guard timer 5759 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5760 * At the expiration of this timer the sender SHOULD abort the association 5761 * by sending an ABORT chunk. 5762 */ 5763 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5764 const struct sctp_endpoint *ep, 5765 const struct sctp_association *asoc, 5766 const sctp_subtype_t type, 5767 void *arg, 5768 sctp_cmd_seq_t *commands) 5769 { 5770 struct sctp_chunk *reply = NULL; 5771 5772 SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); 5773 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5774 5775 reply = sctp_make_abort(asoc, NULL, 0); 5776 if (!reply) 5777 goto nomem; 5778 5779 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5780 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5781 SCTP_ERROR(ETIMEDOUT)); 5782 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5783 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5784 5785 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5786 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5787 5788 return SCTP_DISPOSITION_DELETE_TCB; 5789 nomem: 5790 return SCTP_DISPOSITION_NOMEM; 5791 } 5792 5793 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5794 * the association is automatically closed by starting the shutdown process. 5795 * The work that needs to be done is same as when SHUTDOWN is initiated by 5796 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5797 */ 5798 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5799 struct net *net, 5800 const struct sctp_endpoint *ep, 5801 const struct sctp_association *asoc, 5802 const sctp_subtype_t type, 5803 void *arg, 5804 sctp_cmd_seq_t *commands) 5805 { 5806 int disposition; 5807 5808 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5809 5810 /* From 9.2 Shutdown of an Association 5811 * Upon receipt of the SHUTDOWN primitive from its upper 5812 * layer, the endpoint enters SHUTDOWN-PENDING state and 5813 * remains there until all outstanding data has been 5814 * acknowledged by its peer. The endpoint accepts no new data 5815 * from its upper layer, but retransmits data to the far end 5816 * if necessary to fill gaps. 5817 */ 5818 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5819 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5820 5821 disposition = SCTP_DISPOSITION_CONSUME; 5822 if (sctp_outq_is_empty(&asoc->outqueue)) { 5823 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5824 arg, commands); 5825 } 5826 return disposition; 5827 } 5828 5829 /***************************************************************************** 5830 * These are sa state functions which could apply to all types of events. 5831 ****************************************************************************/ 5832 5833 /* 5834 * This table entry is not implemented. 5835 * 5836 * Inputs 5837 * (endpoint, asoc, chunk) 5838 * 5839 * The return value is the disposition of the chunk. 5840 */ 5841 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5842 const struct sctp_endpoint *ep, 5843 const struct sctp_association *asoc, 5844 const sctp_subtype_t type, 5845 void *arg, 5846 sctp_cmd_seq_t *commands) 5847 { 5848 return SCTP_DISPOSITION_NOT_IMPL; 5849 } 5850 5851 /* 5852 * This table entry represents a bug. 5853 * 5854 * Inputs 5855 * (endpoint, asoc, chunk) 5856 * 5857 * The return value is the disposition of the chunk. 5858 */ 5859 sctp_disposition_t sctp_sf_bug(struct net *net, 5860 const struct sctp_endpoint *ep, 5861 const struct sctp_association *asoc, 5862 const sctp_subtype_t type, 5863 void *arg, 5864 sctp_cmd_seq_t *commands) 5865 { 5866 return SCTP_DISPOSITION_BUG; 5867 } 5868 5869 /* 5870 * This table entry represents the firing of a timer in the wrong state. 5871 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5872 * when the association is in the wrong state. This event should 5873 * be ignored, so as to prevent any rearming of the timer. 5874 * 5875 * Inputs 5876 * (endpoint, asoc, chunk) 5877 * 5878 * The return value is the disposition of the chunk. 5879 */ 5880 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5881 const struct sctp_endpoint *ep, 5882 const struct sctp_association *asoc, 5883 const sctp_subtype_t type, 5884 void *arg, 5885 sctp_cmd_seq_t *commands) 5886 { 5887 SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); 5888 return SCTP_DISPOSITION_CONSUME; 5889 } 5890 5891 /******************************************************************** 5892 * 2nd Level Abstractions 5893 ********************************************************************/ 5894 5895 /* Pull the SACK chunk based on the SACK header. */ 5896 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5897 { 5898 struct sctp_sackhdr *sack; 5899 unsigned int len; 5900 __u16 num_blocks; 5901 __u16 num_dup_tsns; 5902 5903 /* Protect ourselves from reading too far into 5904 * the skb from a bogus sender. 5905 */ 5906 sack = (struct sctp_sackhdr *) chunk->skb->data; 5907 5908 num_blocks = ntohs(sack->num_gap_ack_blocks); 5909 num_dup_tsns = ntohs(sack->num_dup_tsns); 5910 len = sizeof(struct sctp_sackhdr); 5911 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5912 if (len > chunk->skb->len) 5913 return NULL; 5914 5915 skb_pull(chunk->skb, len); 5916 5917 return sack; 5918 } 5919 5920 /* Create an ABORT packet to be sent as a response, with the specified 5921 * error causes. 5922 */ 5923 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 5924 const struct sctp_endpoint *ep, 5925 const struct sctp_association *asoc, 5926 struct sctp_chunk *chunk, 5927 const void *payload, 5928 size_t paylen) 5929 { 5930 struct sctp_packet *packet; 5931 struct sctp_chunk *abort; 5932 5933 packet = sctp_ootb_pkt_new(net, asoc, chunk); 5934 5935 if (packet) { 5936 /* Make an ABORT. 5937 * The T bit will be set if the asoc is NULL. 5938 */ 5939 abort = sctp_make_abort(asoc, chunk, paylen); 5940 if (!abort) { 5941 sctp_ootb_pkt_free(packet); 5942 return NULL; 5943 } 5944 5945 /* Reflect vtag if T-Bit is set */ 5946 if (sctp_test_T_bit(abort)) 5947 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5948 5949 /* Add specified error causes, i.e., payload, to the 5950 * end of the chunk. 5951 */ 5952 sctp_addto_chunk(abort, paylen, payload); 5953 5954 /* Set the skb to the belonging sock for accounting. */ 5955 abort->skb->sk = ep->base.sk; 5956 5957 sctp_packet_append_chunk(packet, abort); 5958 5959 } 5960 5961 return packet; 5962 } 5963 5964 /* Allocate a packet for responding in the OOTB conditions. */ 5965 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 5966 const struct sctp_association *asoc, 5967 const struct sctp_chunk *chunk) 5968 { 5969 struct sctp_packet *packet; 5970 struct sctp_transport *transport; 5971 __u16 sport; 5972 __u16 dport; 5973 __u32 vtag; 5974 5975 /* Get the source and destination port from the inbound packet. */ 5976 sport = ntohs(chunk->sctp_hdr->dest); 5977 dport = ntohs(chunk->sctp_hdr->source); 5978 5979 /* The V-tag is going to be the same as the inbound packet if no 5980 * association exists, otherwise, use the peer's vtag. 5981 */ 5982 if (asoc) { 5983 /* Special case the INIT-ACK as there is no peer's vtag 5984 * yet. 5985 */ 5986 switch(chunk->chunk_hdr->type) { 5987 case SCTP_CID_INIT_ACK: 5988 { 5989 sctp_initack_chunk_t *initack; 5990 5991 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 5992 vtag = ntohl(initack->init_hdr.init_tag); 5993 break; 5994 } 5995 default: 5996 vtag = asoc->peer.i.init_tag; 5997 break; 5998 } 5999 } else { 6000 /* Special case the INIT and stale COOKIE_ECHO as there is no 6001 * vtag yet. 6002 */ 6003 switch(chunk->chunk_hdr->type) { 6004 case SCTP_CID_INIT: 6005 { 6006 sctp_init_chunk_t *init; 6007 6008 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6009 vtag = ntohl(init->init_hdr.init_tag); 6010 break; 6011 } 6012 default: 6013 vtag = ntohl(chunk->sctp_hdr->vtag); 6014 break; 6015 } 6016 } 6017 6018 /* Make a transport for the bucket, Eliza... */ 6019 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6020 if (!transport) 6021 goto nomem; 6022 6023 /* Cache a route for the transport with the chunk's destination as 6024 * the source address. 6025 */ 6026 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6027 sctp_sk(net->sctp.ctl_sock)); 6028 6029 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 6030 packet = sctp_packet_config(packet, vtag, 0); 6031 6032 return packet; 6033 6034 nomem: 6035 return NULL; 6036 } 6037 6038 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6039 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6040 { 6041 sctp_transport_free(packet->transport); 6042 } 6043 6044 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6045 static void sctp_send_stale_cookie_err(struct net *net, 6046 const struct sctp_endpoint *ep, 6047 const struct sctp_association *asoc, 6048 const struct sctp_chunk *chunk, 6049 sctp_cmd_seq_t *commands, 6050 struct sctp_chunk *err_chunk) 6051 { 6052 struct sctp_packet *packet; 6053 6054 if (err_chunk) { 6055 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6056 if (packet) { 6057 struct sctp_signed_cookie *cookie; 6058 6059 /* Override the OOTB vtag from the cookie. */ 6060 cookie = chunk->subh.cookie_hdr; 6061 packet->vtag = cookie->c.peer_vtag; 6062 6063 /* Set the skb to the belonging sock for accounting. */ 6064 err_chunk->skb->sk = ep->base.sk; 6065 sctp_packet_append_chunk(packet, err_chunk); 6066 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6067 SCTP_PACKET(packet)); 6068 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6069 } else 6070 sctp_chunk_free (err_chunk); 6071 } 6072 } 6073 6074 6075 /* Process a data chunk */ 6076 static int sctp_eat_data(const struct sctp_association *asoc, 6077 struct sctp_chunk *chunk, 6078 sctp_cmd_seq_t *commands) 6079 { 6080 sctp_datahdr_t *data_hdr; 6081 struct sctp_chunk *err; 6082 size_t datalen; 6083 sctp_verb_t deliver; 6084 int tmp; 6085 __u32 tsn; 6086 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6087 struct sock *sk = asoc->base.sk; 6088 struct net *net = sock_net(sk); 6089 u16 ssn; 6090 u16 sid; 6091 u8 ordered = 0; 6092 6093 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6094 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6095 6096 tsn = ntohl(data_hdr->tsn); 6097 SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); 6098 6099 /* ASSERT: Now skb->data is really the user data. */ 6100 6101 /* Process ECN based congestion. 6102 * 6103 * Since the chunk structure is reused for all chunks within 6104 * a packet, we use ecn_ce_done to track if we've already 6105 * done CE processing for this packet. 6106 * 6107 * We need to do ECN processing even if we plan to discard the 6108 * chunk later. 6109 */ 6110 6111 if (!chunk->ecn_ce_done) { 6112 struct sctp_af *af; 6113 chunk->ecn_ce_done = 1; 6114 6115 af = sctp_get_af_specific( 6116 ipver2af(ip_hdr(chunk->skb)->version)); 6117 6118 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 6119 /* Do real work as sideffect. */ 6120 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6121 SCTP_U32(tsn)); 6122 } 6123 } 6124 6125 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6126 if (tmp < 0) { 6127 /* The TSN is too high--silently discard the chunk and 6128 * count on it getting retransmitted later. 6129 */ 6130 return SCTP_IERROR_HIGH_TSN; 6131 } else if (tmp > 0) { 6132 /* This is a duplicate. Record it. */ 6133 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6134 return SCTP_IERROR_DUP_TSN; 6135 } 6136 6137 /* This is a new TSN. */ 6138 6139 /* Discard if there is no room in the receive window. 6140 * Actually, allow a little bit of overflow (up to a MTU). 6141 */ 6142 datalen = ntohs(chunk->chunk_hdr->length); 6143 datalen -= sizeof(sctp_data_chunk_t); 6144 6145 deliver = SCTP_CMD_CHUNK_ULP; 6146 6147 /* Think about partial delivery. */ 6148 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6149 6150 /* Even if we don't accept this chunk there is 6151 * memory pressure. 6152 */ 6153 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6154 } 6155 6156 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6157 * seems a bit troublesome in that frag_point varies based on 6158 * PMTU. In cases, such as loopback, this might be a rather 6159 * large spill over. 6160 */ 6161 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6162 (datalen > asoc->rwnd + asoc->frag_point))) { 6163 6164 /* If this is the next TSN, consider reneging to make 6165 * room. Note: Playing nice with a confused sender. A 6166 * malicious sender can still eat up all our buffer 6167 * space and in the future we may want to detect and 6168 * do more drastic reneging. 6169 */ 6170 if (sctp_tsnmap_has_gap(map) && 6171 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6172 SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); 6173 deliver = SCTP_CMD_RENEGE; 6174 } else { 6175 SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " 6176 "rwnd: %d\n", tsn, datalen, 6177 asoc->rwnd); 6178 return SCTP_IERROR_IGNORE_TSN; 6179 } 6180 } 6181 6182 /* 6183 * Also try to renege to limit our memory usage in the event that 6184 * we are under memory pressure 6185 * If we can't renege, don't worry about it, the sk_rmem_schedule 6186 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6187 * memory usage too much 6188 */ 6189 if (*sk->sk_prot_creator->memory_pressure) { 6190 if (sctp_tsnmap_has_gap(map) && 6191 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6192 SCTP_DEBUG_PRINTK("Under Pressure! Reneging for tsn:%u\n", tsn); 6193 deliver = SCTP_CMD_RENEGE; 6194 } 6195 } 6196 6197 /* 6198 * Section 3.3.10.9 No User Data (9) 6199 * 6200 * Cause of error 6201 * --------------- 6202 * No User Data: This error cause is returned to the originator of a 6203 * DATA chunk if a received DATA chunk has no user data. 6204 */ 6205 if (unlikely(0 == datalen)) { 6206 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6207 if (err) { 6208 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6209 SCTP_CHUNK(err)); 6210 } 6211 /* We are going to ABORT, so we might as well stop 6212 * processing the rest of the chunks in the packet. 6213 */ 6214 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 6215 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6216 SCTP_ERROR(ECONNABORTED)); 6217 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6218 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6219 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6220 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6221 return SCTP_IERROR_NO_DATA; 6222 } 6223 6224 chunk->data_accepted = 1; 6225 6226 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6227 * if we renege and the chunk arrives again. 6228 */ 6229 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 6230 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6231 else { 6232 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6233 ordered = 1; 6234 } 6235 6236 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6237 * 6238 * If an endpoint receive a DATA chunk with an invalid stream 6239 * identifier, it shall acknowledge the reception of the DATA chunk 6240 * following the normal procedure, immediately send an ERROR chunk 6241 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6242 * and discard the DATA chunk. 6243 */ 6244 sid = ntohs(data_hdr->stream); 6245 if (sid >= asoc->c.sinit_max_instreams) { 6246 /* Mark tsn as received even though we drop it */ 6247 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6248 6249 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6250 &data_hdr->stream, 6251 sizeof(data_hdr->stream), 6252 sizeof(u16)); 6253 if (err) 6254 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6255 SCTP_CHUNK(err)); 6256 return SCTP_IERROR_BAD_STREAM; 6257 } 6258 6259 /* Check to see if the SSN is possible for this TSN. 6260 * The biggest gap we can record is 4K wide. Since SSNs wrap 6261 * at an unsigned short, there is no way that an SSN can 6262 * wrap and for a valid TSN. We can simply check if the current 6263 * SSN is smaller then the next expected one. If it is, it wrapped 6264 * and is invalid. 6265 */ 6266 ssn = ntohs(data_hdr->ssn); 6267 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6268 return SCTP_IERROR_PROTO_VIOLATION; 6269 } 6270 6271 /* Send the data up to the user. Note: Schedule the 6272 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6273 * chunk needs the updated rwnd. 6274 */ 6275 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6276 6277 return SCTP_IERROR_NO_ERROR; 6278 } 6279