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