1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, see 26 * <http://www.gnu.org/licenses/>. 27 * 28 * Please send any bug reports or fixes you make to the 29 * email address(es): 30 * lksctp developers <linux-sctp@vger.kernel.org> 31 * 32 * Written or modified by: 33 * La Monte H.P. Yarroll <piggy@acm.org> 34 * Karl Knutson <karl@athena.chicago.il.us> 35 * Mathew Kotowsky <kotowsky@sctp.org> 36 * Sridhar Samudrala <samudrala@us.ibm.com> 37 * Jon Grimm <jgrimm@us.ibm.com> 38 * Hui Huang <hui.huang@nokia.com> 39 * Dajiang Zhang <dajiang.zhang@nokia.com> 40 * Daisy Chang <daisyc@us.ibm.com> 41 * Ardelle Fan <ardelle.fan@intel.com> 42 * Ryan Layer <rmlayer@us.ibm.com> 43 * Kevin Gao <kevin.gao@intel.com> 44 */ 45 46 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 47 48 #include <linux/types.h> 49 #include <linux/kernel.h> 50 #include <linux/ip.h> 51 #include <linux/ipv6.h> 52 #include <linux/net.h> 53 #include <linux/inet.h> 54 #include <linux/slab.h> 55 #include <net/sock.h> 56 #include <net/inet_ecn.h> 57 #include <linux/skbuff.h> 58 #include <net/sctp/sctp.h> 59 #include <net/sctp/sm.h> 60 #include <net/sctp/structs.h> 61 62 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 63 const struct sctp_endpoint *ep, 64 const struct sctp_association *asoc, 65 struct sctp_chunk *chunk, 66 const void *payload, 67 size_t paylen); 68 static int sctp_eat_data(const struct sctp_association *asoc, 69 struct sctp_chunk *chunk, 70 sctp_cmd_seq_t *commands); 71 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 72 const struct sctp_association *asoc, 73 const struct sctp_chunk *chunk); 74 static void sctp_send_stale_cookie_err(struct net *net, 75 const struct sctp_endpoint *ep, 76 const struct sctp_association *asoc, 77 const struct sctp_chunk *chunk, 78 sctp_cmd_seq_t *commands, 79 struct sctp_chunk *err_chunk); 80 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 81 const struct sctp_endpoint *ep, 82 const struct sctp_association *asoc, 83 const sctp_subtype_t type, 84 void *arg, 85 sctp_cmd_seq_t *commands); 86 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const sctp_subtype_t type, 90 void *arg, 91 sctp_cmd_seq_t *commands); 92 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 93 const struct sctp_endpoint *ep, 94 const struct sctp_association *asoc, 95 const sctp_subtype_t type, 96 void *arg, 97 sctp_cmd_seq_t *commands); 98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 99 100 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 101 sctp_cmd_seq_t *commands, 102 __be16 error, int sk_err, 103 const struct sctp_association *asoc, 104 struct sctp_transport *transport); 105 106 static sctp_disposition_t sctp_sf_abort_violation( 107 struct net *net, 108 const struct sctp_endpoint *ep, 109 const struct sctp_association *asoc, 110 void *arg, 111 sctp_cmd_seq_t *commands, 112 const __u8 *payload, 113 const size_t paylen); 114 115 static sctp_disposition_t sctp_sf_violation_chunklen( 116 struct net *net, 117 const struct sctp_endpoint *ep, 118 const struct sctp_association *asoc, 119 const sctp_subtype_t type, 120 void *arg, 121 sctp_cmd_seq_t *commands); 122 123 static sctp_disposition_t sctp_sf_violation_paramlen( 124 struct net *net, 125 const struct sctp_endpoint *ep, 126 const struct sctp_association *asoc, 127 const sctp_subtype_t type, 128 void *arg, void *ext, 129 sctp_cmd_seq_t *commands); 130 131 static sctp_disposition_t sctp_sf_violation_ctsn( 132 struct net *net, 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const sctp_subtype_t type, 136 void *arg, 137 sctp_cmd_seq_t *commands); 138 139 static sctp_disposition_t sctp_sf_violation_chunk( 140 struct net *net, 141 const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const sctp_subtype_t type, 144 void *arg, 145 sctp_cmd_seq_t *commands); 146 147 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 148 const struct sctp_endpoint *ep, 149 const struct sctp_association *asoc, 150 const sctp_subtype_t type, 151 struct sctp_chunk *chunk); 152 153 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 154 const struct sctp_endpoint *ep, 155 const struct sctp_association *asoc, 156 const sctp_subtype_t type, 157 void *arg, 158 sctp_cmd_seq_t *commands); 159 160 /* Small helper function that checks if the chunk length 161 * is of the appropriate length. The 'required_length' argument 162 * is set to be the size of a specific chunk we are testing. 163 * Return Values: 1 = Valid length 164 * 0 = Invalid length 165 * 166 */ 167 static inline int 168 sctp_chunk_length_valid(struct sctp_chunk *chunk, 169 __u16 required_length) 170 { 171 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 172 173 if (unlikely(chunk_length < required_length)) 174 return 0; 175 176 return 1; 177 } 178 179 /********************************************************** 180 * These are the state functions for handling chunk events. 181 **********************************************************/ 182 183 /* 184 * Process the final SHUTDOWN COMPLETE. 185 * 186 * Section: 4 (C) (diagram), 9.2 187 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 188 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 189 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 190 * should stop the T2-shutdown timer and remove all knowledge of the 191 * association (and thus the association enters the CLOSED state). 192 * 193 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 194 * C) Rules for packet carrying SHUTDOWN COMPLETE: 195 * ... 196 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 197 * if the Verification Tag field of the packet matches its own tag and 198 * the T bit is not set 199 * OR 200 * it is set to its peer's tag and the T bit is set in the Chunk 201 * Flags. 202 * Otherwise, the receiver MUST silently discard the packet 203 * and take no further action. An endpoint MUST ignore the 204 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 205 * 206 * Inputs 207 * (endpoint, asoc, chunk) 208 * 209 * Outputs 210 * (asoc, reply_msg, msg_up, timers, counters) 211 * 212 * The return value is the disposition of the chunk. 213 */ 214 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 215 const struct sctp_endpoint *ep, 216 const struct sctp_association *asoc, 217 const sctp_subtype_t type, 218 void *arg, 219 sctp_cmd_seq_t *commands) 220 { 221 struct sctp_chunk *chunk = arg; 222 struct sctp_ulpevent *ev; 223 224 if (!sctp_vtag_verify_either(chunk, asoc)) 225 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 226 227 /* RFC 2960 6.10 Bundling 228 * 229 * An endpoint MUST NOT bundle INIT, INIT ACK or 230 * SHUTDOWN COMPLETE with any other chunks. 231 */ 232 if (!chunk->singleton) 233 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 234 235 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 236 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 237 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 238 commands); 239 240 /* RFC 2960 10.2 SCTP-to-ULP 241 * 242 * H) SHUTDOWN COMPLETE notification 243 * 244 * When SCTP completes the shutdown procedures (section 9.2) this 245 * notification is passed to the upper layer. 246 */ 247 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 248 0, 0, 0, NULL, GFP_ATOMIC); 249 if (ev) 250 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 251 SCTP_ULPEVENT(ev)); 252 253 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 254 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 255 * not the chunk should be discarded. If the endpoint is in 256 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 257 * T2-shutdown timer and remove all knowledge of the 258 * association (and thus the association enters the CLOSED 259 * state). 260 */ 261 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 262 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 263 264 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 265 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 266 267 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 268 SCTP_STATE(SCTP_STATE_CLOSED)); 269 270 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 271 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 272 273 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 274 275 return SCTP_DISPOSITION_DELETE_TCB; 276 } 277 278 /* 279 * Respond to a normal INIT chunk. 280 * We are the side that is being asked for an association. 281 * 282 * Section: 5.1 Normal Establishment of an Association, B 283 * B) "Z" shall respond immediately with an INIT ACK chunk. The 284 * destination IP address of the INIT ACK MUST be set to the source 285 * IP address of the INIT to which this INIT ACK is responding. In 286 * the response, besides filling in other parameters, "Z" must set the 287 * Verification Tag field to Tag_A, and also provide its own 288 * Verification Tag (Tag_Z) in the Initiate Tag field. 289 * 290 * Verification Tag: Must be 0. 291 * 292 * Inputs 293 * (endpoint, asoc, chunk) 294 * 295 * Outputs 296 * (asoc, reply_msg, msg_up, timers, counters) 297 * 298 * The return value is the disposition of the chunk. 299 */ 300 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 301 const struct sctp_endpoint *ep, 302 const struct sctp_association *asoc, 303 const sctp_subtype_t type, 304 void *arg, 305 sctp_cmd_seq_t *commands) 306 { 307 struct sctp_chunk *chunk = arg; 308 struct sctp_chunk *repl; 309 struct sctp_association *new_asoc; 310 struct sctp_chunk *err_chunk; 311 struct sctp_packet *packet; 312 sctp_unrecognized_param_t *unk_param; 313 int len; 314 315 /* 6.10 Bundling 316 * An endpoint MUST NOT bundle INIT, INIT ACK or 317 * SHUTDOWN COMPLETE with any other chunks. 318 * 319 * IG Section 2.11.2 320 * Furthermore, we require that the receiver of an INIT chunk MUST 321 * enforce these rules by silently discarding an arriving packet 322 * with an INIT chunk that is bundled with other chunks. 323 */ 324 if (!chunk->singleton) 325 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 326 327 /* If the packet is an OOTB packet which is temporarily on the 328 * control endpoint, respond with an ABORT. 329 */ 330 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 331 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 332 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 333 } 334 335 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 336 * Tag. 337 */ 338 if (chunk->sctp_hdr->vtag != 0) 339 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 340 341 /* Make sure that the INIT chunk has a valid length. 342 * Normally, this would cause an ABORT with a Protocol Violation 343 * error, but since we don't have an association, we'll 344 * just discard the packet. 345 */ 346 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 348 349 /* If the INIT is coming toward a closing socket, we'll send back 350 * and ABORT. Essentially, this catches the race of INIT being 351 * backloged to the socket at the same time as the user isses close(). 352 * Since the socket and all its associations are going away, we 353 * can treat this OOTB 354 */ 355 if (sctp_sstate(ep->base.sk, CLOSING)) 356 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 357 358 /* Verify the INIT chunk before processing it. */ 359 err_chunk = NULL; 360 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 361 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 362 &err_chunk)) { 363 /* This chunk contains fatal error. It is to be discarded. 364 * Send an ABORT, with causes if there is any. 365 */ 366 if (err_chunk) { 367 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 368 (__u8 *)(err_chunk->chunk_hdr) + 369 sizeof(sctp_chunkhdr_t), 370 ntohs(err_chunk->chunk_hdr->length) - 371 sizeof(sctp_chunkhdr_t)); 372 373 sctp_chunk_free(err_chunk); 374 375 if (packet) { 376 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 377 SCTP_PACKET(packet)); 378 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 379 return SCTP_DISPOSITION_CONSUME; 380 } else { 381 return SCTP_DISPOSITION_NOMEM; 382 } 383 } else { 384 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 385 commands); 386 } 387 } 388 389 /* Grab the INIT header. */ 390 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 391 392 /* Tag the variable length parameters. */ 393 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 394 395 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 396 if (!new_asoc) 397 goto nomem; 398 399 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 400 sctp_scope(sctp_source(chunk)), 401 GFP_ATOMIC) < 0) 402 goto nomem_init; 403 404 /* The call, sctp_process_init(), can fail on memory allocation. */ 405 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 406 (sctp_init_chunk_t *)chunk->chunk_hdr, 407 GFP_ATOMIC)) 408 goto nomem_init; 409 410 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 411 412 /* If there are errors need to be reported for unknown parameters, 413 * make sure to reserve enough room in the INIT ACK for them. 414 */ 415 len = 0; 416 if (err_chunk) 417 len = ntohs(err_chunk->chunk_hdr->length) - 418 sizeof(sctp_chunkhdr_t); 419 420 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 421 if (!repl) 422 goto nomem_init; 423 424 /* If there are errors need to be reported for unknown parameters, 425 * include them in the outgoing INIT ACK as "Unrecognized parameter" 426 * parameter. 427 */ 428 if (err_chunk) { 429 /* Get the "Unrecognized parameter" parameter(s) out of the 430 * ERROR chunk generated by sctp_verify_init(). Since the 431 * error cause code for "unknown parameter" and the 432 * "Unrecognized parameter" type is the same, we can 433 * construct the parameters in INIT ACK by copying the 434 * ERROR causes over. 435 */ 436 unk_param = (sctp_unrecognized_param_t *) 437 ((__u8 *)(err_chunk->chunk_hdr) + 438 sizeof(sctp_chunkhdr_t)); 439 /* Replace the cause code with the "Unrecognized parameter" 440 * parameter type. 441 */ 442 sctp_addto_chunk(repl, len, unk_param); 443 sctp_chunk_free(err_chunk); 444 } 445 446 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 447 448 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 449 450 /* 451 * Note: After sending out INIT ACK with the State Cookie parameter, 452 * "Z" MUST NOT allocate any resources, nor keep any states for the 453 * new association. Otherwise, "Z" will be vulnerable to resource 454 * attacks. 455 */ 456 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 457 458 return SCTP_DISPOSITION_DELETE_TCB; 459 460 nomem_init: 461 sctp_association_free(new_asoc); 462 nomem: 463 if (err_chunk) 464 sctp_chunk_free(err_chunk); 465 return SCTP_DISPOSITION_NOMEM; 466 } 467 468 /* 469 * Respond to a normal INIT ACK chunk. 470 * We are the side that is initiating the association. 471 * 472 * Section: 5.1 Normal Establishment of an Association, C 473 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 474 * timer and leave COOKIE-WAIT state. "A" shall then send the State 475 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 476 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 477 * 478 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 479 * DATA chunks, but it MUST be the first chunk in the packet and 480 * until the COOKIE ACK is returned the sender MUST NOT send any 481 * other packets to the peer. 482 * 483 * Verification Tag: 3.3.3 484 * If the value of the Initiate Tag in a received INIT ACK chunk is 485 * found to be 0, the receiver MUST treat it as an error and close the 486 * association by transmitting an ABORT. 487 * 488 * Inputs 489 * (endpoint, asoc, chunk) 490 * 491 * Outputs 492 * (asoc, reply_msg, msg_up, timers, counters) 493 * 494 * The return value is the disposition of the chunk. 495 */ 496 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 497 const struct sctp_endpoint *ep, 498 const struct sctp_association *asoc, 499 const sctp_subtype_t type, 500 void *arg, 501 sctp_cmd_seq_t *commands) 502 { 503 struct sctp_chunk *chunk = arg; 504 sctp_init_chunk_t *initchunk; 505 struct sctp_chunk *err_chunk; 506 struct sctp_packet *packet; 507 508 if (!sctp_vtag_verify(chunk, asoc)) 509 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 510 511 /* 6.10 Bundling 512 * An endpoint MUST NOT bundle INIT, INIT ACK or 513 * SHUTDOWN COMPLETE with any other chunks. 514 */ 515 if (!chunk->singleton) 516 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 517 518 /* Make sure that the INIT-ACK chunk has a valid length */ 519 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 520 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 521 commands); 522 /* Grab the INIT header. */ 523 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 524 525 /* Verify the INIT chunk before processing it. */ 526 err_chunk = NULL; 527 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 528 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 529 &err_chunk)) { 530 531 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 532 533 /* This chunk contains fatal error. It is to be discarded. 534 * Send an ABORT, with causes. If there are no causes, 535 * then there wasn't enough memory. Just terminate 536 * the association. 537 */ 538 if (err_chunk) { 539 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 540 (__u8 *)(err_chunk->chunk_hdr) + 541 sizeof(sctp_chunkhdr_t), 542 ntohs(err_chunk->chunk_hdr->length) - 543 sizeof(sctp_chunkhdr_t)); 544 545 sctp_chunk_free(err_chunk); 546 547 if (packet) { 548 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 549 SCTP_PACKET(packet)); 550 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 551 error = SCTP_ERROR_INV_PARAM; 552 } 553 } 554 555 /* SCTP-AUTH, Section 6.3: 556 * It should be noted that if the receiver wants to tear 557 * down an association in an authenticated way only, the 558 * handling of malformed packets should not result in 559 * tearing down the association. 560 * 561 * This means that if we only want to abort associations 562 * in an authenticated way (i.e AUTH+ABORT), then we 563 * can't destroy this association just because the packet 564 * was malformed. 565 */ 566 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 567 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 568 569 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 570 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 571 asoc, chunk->transport); 572 } 573 574 /* Tag the variable length parameters. Note that we never 575 * convert the parameters in an INIT chunk. 576 */ 577 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 578 579 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 580 581 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 582 SCTP_PEER_INIT(initchunk)); 583 584 /* Reset init error count upon receipt of INIT-ACK. */ 585 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 586 587 /* 5.1 C) "A" shall stop the T1-init timer and leave 588 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 589 * timer, and enter the COOKIE-ECHOED state. 590 */ 591 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 592 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 593 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 594 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 595 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 596 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 597 598 /* SCTP-AUTH: genereate the assocition shared keys so that 599 * we can potentially signe the COOKIE-ECHO. 600 */ 601 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 602 603 /* 5.1 C) "A" shall then send the State Cookie received in the 604 * INIT ACK chunk in a COOKIE ECHO chunk, ... 605 */ 606 /* If there is any errors to report, send the ERROR chunk generated 607 * for unknown parameters as well. 608 */ 609 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 610 SCTP_CHUNK(err_chunk)); 611 612 return SCTP_DISPOSITION_CONSUME; 613 } 614 615 /* 616 * Respond to a normal COOKIE ECHO chunk. 617 * We are the side that is being asked for an association. 618 * 619 * Section: 5.1 Normal Establishment of an Association, D 620 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 621 * with a COOKIE ACK chunk after building a TCB and moving to 622 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 623 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 624 * chunk MUST be the first chunk in the packet. 625 * 626 * IMPLEMENTATION NOTE: An implementation may choose to send the 627 * Communication Up notification to the SCTP user upon reception 628 * of a valid COOKIE ECHO chunk. 629 * 630 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 631 * D) Rules for packet carrying a COOKIE ECHO 632 * 633 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 634 * Initial Tag received in the INIT ACK. 635 * 636 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 637 * 638 * Inputs 639 * (endpoint, asoc, chunk) 640 * 641 * Outputs 642 * (asoc, reply_msg, msg_up, timers, counters) 643 * 644 * The return value is the disposition of the chunk. 645 */ 646 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 647 const struct sctp_endpoint *ep, 648 const struct sctp_association *asoc, 649 const sctp_subtype_t type, void *arg, 650 sctp_cmd_seq_t *commands) 651 { 652 struct sctp_chunk *chunk = arg; 653 struct sctp_association *new_asoc; 654 sctp_init_chunk_t *peer_init; 655 struct sctp_chunk *repl; 656 struct sctp_ulpevent *ev, *ai_ev = NULL; 657 int error = 0; 658 struct sctp_chunk *err_chk_p; 659 struct sock *sk; 660 661 /* If the packet is an OOTB packet which is temporarily on the 662 * control endpoint, respond with an ABORT. 663 */ 664 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 665 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 666 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 667 } 668 669 /* Make sure that the COOKIE_ECHO chunk has a valid length. 670 * In this case, we check that we have enough for at least a 671 * chunk header. More detailed verification is done 672 * in sctp_unpack_cookie(). 673 */ 674 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 675 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 676 677 /* If the endpoint is not listening or if the number of associations 678 * on the TCP-style socket exceed the max backlog, respond with an 679 * ABORT. 680 */ 681 sk = ep->base.sk; 682 if (!sctp_sstate(sk, LISTENING) || 683 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 684 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 685 686 /* "Decode" the chunk. We have no optional parameters so we 687 * are in good shape. 688 */ 689 chunk->subh.cookie_hdr = 690 (struct sctp_signed_cookie *)chunk->skb->data; 691 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 692 sizeof(sctp_chunkhdr_t))) 693 goto nomem; 694 695 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 696 * "Z" will reply with a COOKIE ACK chunk after building a TCB 697 * and moving to the ESTABLISHED state. 698 */ 699 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 700 &err_chk_p); 701 702 /* FIXME: 703 * If the re-build failed, what is the proper error path 704 * from here? 705 * 706 * [We should abort the association. --piggy] 707 */ 708 if (!new_asoc) { 709 /* FIXME: Several errors are possible. A bad cookie should 710 * be silently discarded, but think about logging it too. 711 */ 712 switch (error) { 713 case -SCTP_IERROR_NOMEM: 714 goto nomem; 715 716 case -SCTP_IERROR_STALE_COOKIE: 717 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 718 err_chk_p); 719 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 720 721 case -SCTP_IERROR_BAD_SIG: 722 default: 723 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 724 } 725 } 726 727 728 /* Delay state machine commands until later. 729 * 730 * Re-build the bind address for the association is done in 731 * the sctp_unpack_cookie() already. 732 */ 733 /* This is a brand-new association, so these are not yet side 734 * effects--it is safe to run them here. 735 */ 736 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 737 738 if (!sctp_process_init(new_asoc, chunk, 739 &chunk->subh.cookie_hdr->c.peer_addr, 740 peer_init, GFP_ATOMIC)) 741 goto nomem_init; 742 743 /* SCTP-AUTH: Now that we've populate required fields in 744 * sctp_process_init, set up the assocaition shared keys as 745 * necessary so that we can potentially authenticate the ACK 746 */ 747 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 748 if (error) 749 goto nomem_init; 750 751 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 752 * is supposed to be authenticated and we have to do delayed 753 * authentication. We've just recreated the association using 754 * the information in the cookie and now it's much easier to 755 * do the authentication. 756 */ 757 if (chunk->auth_chunk) { 758 struct sctp_chunk auth; 759 sctp_ierror_t ret; 760 761 /* set-up our fake chunk so that we can process it */ 762 auth.skb = chunk->auth_chunk; 763 auth.asoc = chunk->asoc; 764 auth.sctp_hdr = chunk->sctp_hdr; 765 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 766 sizeof(sctp_chunkhdr_t)); 767 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 768 auth.transport = chunk->transport; 769 770 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 771 772 /* We can now safely free the auth_chunk clone */ 773 kfree_skb(chunk->auth_chunk); 774 775 if (ret != SCTP_IERROR_NO_ERROR) { 776 sctp_association_free(new_asoc); 777 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 778 } 779 } 780 781 repl = sctp_make_cookie_ack(new_asoc, chunk); 782 if (!repl) 783 goto nomem_init; 784 785 /* RFC 2960 5.1 Normal Establishment of an Association 786 * 787 * D) IMPLEMENTATION NOTE: An implementation may choose to 788 * send the Communication Up notification to the SCTP user 789 * upon reception of a valid COOKIE ECHO chunk. 790 */ 791 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 792 new_asoc->c.sinit_num_ostreams, 793 new_asoc->c.sinit_max_instreams, 794 NULL, GFP_ATOMIC); 795 if (!ev) 796 goto nomem_ev; 797 798 /* Sockets API Draft Section 5.3.1.6 799 * When a peer sends a Adaptation Layer Indication parameter , SCTP 800 * delivers this notification to inform the application that of the 801 * peers requested adaptation layer. 802 */ 803 if (new_asoc->peer.adaptation_ind) { 804 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 805 GFP_ATOMIC); 806 if (!ai_ev) 807 goto nomem_aiev; 808 } 809 810 /* Add all the state machine commands now since we've created 811 * everything. This way we don't introduce memory corruptions 812 * during side-effect processing and correclty count established 813 * associations. 814 */ 815 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 816 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 817 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 818 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 819 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 820 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 821 822 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 823 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 824 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 825 826 /* This will send the COOKIE ACK */ 827 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 828 829 /* Queue the ASSOC_CHANGE event */ 830 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 831 832 /* Send up the Adaptation Layer Indication event */ 833 if (ai_ev) 834 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 835 SCTP_ULPEVENT(ai_ev)); 836 837 return SCTP_DISPOSITION_CONSUME; 838 839 nomem_aiev: 840 sctp_ulpevent_free(ev); 841 nomem_ev: 842 sctp_chunk_free(repl); 843 nomem_init: 844 sctp_association_free(new_asoc); 845 nomem: 846 return SCTP_DISPOSITION_NOMEM; 847 } 848 849 /* 850 * Respond to a normal COOKIE ACK chunk. 851 * We are the side that is being asked for an association. 852 * 853 * RFC 2960 5.1 Normal Establishment of an Association 854 * 855 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 856 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 857 * timer. It may also notify its ULP about the successful 858 * establishment of the association with a Communication Up 859 * notification (see Section 10). 860 * 861 * Verification Tag: 862 * Inputs 863 * (endpoint, asoc, chunk) 864 * 865 * Outputs 866 * (asoc, reply_msg, msg_up, timers, counters) 867 * 868 * The return value is the disposition of the chunk. 869 */ 870 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 871 const struct sctp_endpoint *ep, 872 const struct sctp_association *asoc, 873 const sctp_subtype_t type, void *arg, 874 sctp_cmd_seq_t *commands) 875 { 876 struct sctp_chunk *chunk = arg; 877 struct sctp_ulpevent *ev; 878 879 if (!sctp_vtag_verify(chunk, asoc)) 880 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 881 882 /* Verify that the chunk length for the COOKIE-ACK is OK. 883 * If we don't do this, any bundled chunks may be junked. 884 */ 885 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 886 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 887 commands); 888 889 /* Reset init error count upon receipt of COOKIE-ACK, 890 * to avoid problems with the managemement of this 891 * counter in stale cookie situations when a transition back 892 * from the COOKIE-ECHOED state to the COOKIE-WAIT 893 * state is performed. 894 */ 895 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 896 897 /* RFC 2960 5.1 Normal Establishment of an Association 898 * 899 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 900 * from the COOKIE-ECHOED state to the ESTABLISHED state, 901 * stopping the T1-cookie timer. 902 */ 903 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 904 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 905 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 906 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 907 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 908 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 909 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 910 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 911 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 912 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 913 914 /* It may also notify its ULP about the successful 915 * establishment of the association with a Communication Up 916 * notification (see Section 10). 917 */ 918 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 919 0, asoc->c.sinit_num_ostreams, 920 asoc->c.sinit_max_instreams, 921 NULL, GFP_ATOMIC); 922 923 if (!ev) 924 goto nomem; 925 926 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 927 928 /* Sockets API Draft Section 5.3.1.6 929 * When a peer sends a Adaptation Layer Indication parameter , SCTP 930 * delivers this notification to inform the application that of the 931 * peers requested adaptation layer. 932 */ 933 if (asoc->peer.adaptation_ind) { 934 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 935 if (!ev) 936 goto nomem; 937 938 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 939 SCTP_ULPEVENT(ev)); 940 } 941 942 return SCTP_DISPOSITION_CONSUME; 943 nomem: 944 return SCTP_DISPOSITION_NOMEM; 945 } 946 947 /* Generate and sendout a heartbeat packet. */ 948 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 949 const struct sctp_association *asoc, 950 const sctp_subtype_t type, 951 void *arg, 952 sctp_cmd_seq_t *commands) 953 { 954 struct sctp_transport *transport = (struct sctp_transport *) arg; 955 struct sctp_chunk *reply; 956 957 /* Send a heartbeat to our peer. */ 958 reply = sctp_make_heartbeat(asoc, transport); 959 if (!reply) 960 return SCTP_DISPOSITION_NOMEM; 961 962 /* Set rto_pending indicating that an RTT measurement 963 * is started with this heartbeat chunk. 964 */ 965 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 966 SCTP_TRANSPORT(transport)); 967 968 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 969 return SCTP_DISPOSITION_CONSUME; 970 } 971 972 /* Generate a HEARTBEAT packet on the given transport. */ 973 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 974 const struct sctp_endpoint *ep, 975 const struct sctp_association *asoc, 976 const sctp_subtype_t type, 977 void *arg, 978 sctp_cmd_seq_t *commands) 979 { 980 struct sctp_transport *transport = (struct sctp_transport *) arg; 981 982 if (asoc->overall_error_count >= asoc->max_retrans) { 983 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 984 SCTP_ERROR(ETIMEDOUT)); 985 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 986 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 987 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 988 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 989 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 990 return SCTP_DISPOSITION_DELETE_TCB; 991 } 992 993 /* Section 3.3.5. 994 * The Sender-specific Heartbeat Info field should normally include 995 * information about the sender's current time when this HEARTBEAT 996 * chunk is sent and the destination transport address to which this 997 * HEARTBEAT is sent (see Section 8.3). 998 */ 999 1000 if (transport->param_flags & SPP_HB_ENABLE) { 1001 if (SCTP_DISPOSITION_NOMEM == 1002 sctp_sf_heartbeat(ep, asoc, type, arg, 1003 commands)) 1004 return SCTP_DISPOSITION_NOMEM; 1005 1006 /* Set transport error counter and association error counter 1007 * when sending heartbeat. 1008 */ 1009 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1010 SCTP_TRANSPORT(transport)); 1011 } 1012 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1013 SCTP_TRANSPORT(transport)); 1014 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1015 SCTP_TRANSPORT(transport)); 1016 1017 return SCTP_DISPOSITION_CONSUME; 1018 } 1019 1020 /* 1021 * Process an heartbeat request. 1022 * 1023 * Section: 8.3 Path Heartbeat 1024 * The receiver of the HEARTBEAT should immediately respond with a 1025 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1026 * from the received HEARTBEAT chunk. 1027 * 1028 * Verification Tag: 8.5 Verification Tag [Normal verification] 1029 * When receiving an SCTP packet, the endpoint MUST ensure that the 1030 * value in the Verification Tag field of the received SCTP packet 1031 * matches its own Tag. If the received Verification Tag value does not 1032 * match the receiver's own tag value, the receiver shall silently 1033 * discard the packet and shall not process it any further except for 1034 * those cases listed in Section 8.5.1 below. 1035 * 1036 * Inputs 1037 * (endpoint, asoc, chunk) 1038 * 1039 * Outputs 1040 * (asoc, reply_msg, msg_up, timers, counters) 1041 * 1042 * The return value is the disposition of the chunk. 1043 */ 1044 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1045 const struct sctp_endpoint *ep, 1046 const struct sctp_association *asoc, 1047 const sctp_subtype_t type, 1048 void *arg, 1049 sctp_cmd_seq_t *commands) 1050 { 1051 sctp_paramhdr_t *param_hdr; 1052 struct sctp_chunk *chunk = arg; 1053 struct sctp_chunk *reply; 1054 size_t paylen = 0; 1055 1056 if (!sctp_vtag_verify(chunk, asoc)) 1057 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1058 1059 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1060 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1061 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1062 commands); 1063 1064 /* 8.3 The receiver of the HEARTBEAT should immediately 1065 * respond with a HEARTBEAT ACK that contains the Heartbeat 1066 * Information field copied from the received HEARTBEAT chunk. 1067 */ 1068 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1069 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr; 1070 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1071 1072 if (ntohs(param_hdr->length) > paylen) 1073 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1074 param_hdr, commands); 1075 1076 if (!pskb_pull(chunk->skb, paylen)) 1077 goto nomem; 1078 1079 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1080 if (!reply) 1081 goto nomem; 1082 1083 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1084 return SCTP_DISPOSITION_CONSUME; 1085 1086 nomem: 1087 return SCTP_DISPOSITION_NOMEM; 1088 } 1089 1090 /* 1091 * Process the returning HEARTBEAT ACK. 1092 * 1093 * Section: 8.3 Path Heartbeat 1094 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1095 * should clear the error counter of the destination transport 1096 * address to which the HEARTBEAT was sent, and mark the destination 1097 * transport address as active if it is not so marked. The endpoint may 1098 * optionally report to the upper layer when an inactive destination 1099 * address is marked as active due to the reception of the latest 1100 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1101 * clear the association overall error count as well (as defined 1102 * in section 8.1). 1103 * 1104 * The receiver of the HEARTBEAT ACK should also perform an RTT 1105 * measurement for that destination transport address using the time 1106 * value carried in the HEARTBEAT ACK chunk. 1107 * 1108 * Verification Tag: 8.5 Verification Tag [Normal verification] 1109 * 1110 * Inputs 1111 * (endpoint, asoc, chunk) 1112 * 1113 * Outputs 1114 * (asoc, reply_msg, msg_up, timers, counters) 1115 * 1116 * The return value is the disposition of the chunk. 1117 */ 1118 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1119 const struct sctp_endpoint *ep, 1120 const struct sctp_association *asoc, 1121 const sctp_subtype_t type, 1122 void *arg, 1123 sctp_cmd_seq_t *commands) 1124 { 1125 struct sctp_chunk *chunk = arg; 1126 union sctp_addr from_addr; 1127 struct sctp_transport *link; 1128 sctp_sender_hb_info_t *hbinfo; 1129 unsigned long max_interval; 1130 1131 if (!sctp_vtag_verify(chunk, asoc)) 1132 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1133 1134 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1135 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1136 sizeof(sctp_sender_hb_info_t))) 1137 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1138 commands); 1139 1140 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1141 /* Make sure that the length of the parameter is what we expect */ 1142 if (ntohs(hbinfo->param_hdr.length) != 1143 sizeof(sctp_sender_hb_info_t)) { 1144 return SCTP_DISPOSITION_DISCARD; 1145 } 1146 1147 from_addr = hbinfo->daddr; 1148 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1149 1150 /* This should never happen, but lets log it if so. */ 1151 if (unlikely(!link)) { 1152 if (from_addr.sa.sa_family == AF_INET6) { 1153 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1154 __func__, 1155 asoc, 1156 &from_addr.v6.sin6_addr); 1157 } else { 1158 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1159 __func__, 1160 asoc, 1161 &from_addr.v4.sin_addr.s_addr); 1162 } 1163 return SCTP_DISPOSITION_DISCARD; 1164 } 1165 1166 /* Validate the 64-bit random nonce. */ 1167 if (hbinfo->hb_nonce != link->hb_nonce) 1168 return SCTP_DISPOSITION_DISCARD; 1169 1170 max_interval = link->hbinterval + link->rto; 1171 1172 /* Check if the timestamp looks valid. */ 1173 if (time_after(hbinfo->sent_at, jiffies) || 1174 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1175 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1176 "for transport:%p\n", __func__, link); 1177 1178 return SCTP_DISPOSITION_DISCARD; 1179 } 1180 1181 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1182 * the HEARTBEAT should clear the error counter of the 1183 * destination transport address to which the HEARTBEAT was 1184 * sent and mark the destination transport address as active if 1185 * it is not so marked. 1186 */ 1187 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1188 1189 return SCTP_DISPOSITION_CONSUME; 1190 } 1191 1192 /* Helper function to send out an abort for the restart 1193 * condition. 1194 */ 1195 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1196 struct sctp_chunk *init, 1197 sctp_cmd_seq_t *commands) 1198 { 1199 int len; 1200 struct sctp_packet *pkt; 1201 union sctp_addr_param *addrparm; 1202 struct sctp_errhdr *errhdr; 1203 struct sctp_endpoint *ep; 1204 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1205 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1206 1207 /* Build the error on the stack. We are way to malloc crazy 1208 * throughout the code today. 1209 */ 1210 errhdr = (struct sctp_errhdr *)buffer; 1211 addrparm = (union sctp_addr_param *)errhdr->variable; 1212 1213 /* Copy into a parm format. */ 1214 len = af->to_addr_param(ssa, addrparm); 1215 len += sizeof(sctp_errhdr_t); 1216 1217 errhdr->cause = SCTP_ERROR_RESTART; 1218 errhdr->length = htons(len); 1219 1220 /* Assign to the control socket. */ 1221 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1222 1223 /* Association is NULL since this may be a restart attack and we 1224 * want to send back the attacker's vtag. 1225 */ 1226 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1227 1228 if (!pkt) 1229 goto out; 1230 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1231 1232 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1233 1234 /* Discard the rest of the inbound packet. */ 1235 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1236 1237 out: 1238 /* Even if there is no memory, treat as a failure so 1239 * the packet will get dropped. 1240 */ 1241 return 0; 1242 } 1243 1244 static bool list_has_sctp_addr(const struct list_head *list, 1245 union sctp_addr *ipaddr) 1246 { 1247 struct sctp_transport *addr; 1248 1249 list_for_each_entry(addr, list, transports) { 1250 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1251 return true; 1252 } 1253 1254 return false; 1255 } 1256 /* A restart is occurring, check to make sure no new addresses 1257 * are being added as we may be under a takeover attack. 1258 */ 1259 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1260 const struct sctp_association *asoc, 1261 struct sctp_chunk *init, 1262 sctp_cmd_seq_t *commands) 1263 { 1264 struct net *net = sock_net(new_asoc->base.sk); 1265 struct sctp_transport *new_addr; 1266 int ret = 1; 1267 1268 /* Implementor's Guide - Section 5.2.2 1269 * ... 1270 * Before responding the endpoint MUST check to see if the 1271 * unexpected INIT adds new addresses to the association. If new 1272 * addresses are added to the association, the endpoint MUST respond 1273 * with an ABORT.. 1274 */ 1275 1276 /* Search through all current addresses and make sure 1277 * we aren't adding any new ones. 1278 */ 1279 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1280 transports) { 1281 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1282 &new_addr->ipaddr)) { 1283 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1284 commands); 1285 ret = 0; 1286 break; 1287 } 1288 } 1289 1290 /* Return success if all addresses were found. */ 1291 return ret; 1292 } 1293 1294 /* Populate the verification/tie tags based on overlapping INIT 1295 * scenario. 1296 * 1297 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1298 */ 1299 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1300 const struct sctp_association *asoc) 1301 { 1302 switch (asoc->state) { 1303 1304 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1305 1306 case SCTP_STATE_COOKIE_WAIT: 1307 new_asoc->c.my_vtag = asoc->c.my_vtag; 1308 new_asoc->c.my_ttag = asoc->c.my_vtag; 1309 new_asoc->c.peer_ttag = 0; 1310 break; 1311 1312 case SCTP_STATE_COOKIE_ECHOED: 1313 new_asoc->c.my_vtag = asoc->c.my_vtag; 1314 new_asoc->c.my_ttag = asoc->c.my_vtag; 1315 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1316 break; 1317 1318 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1319 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1320 */ 1321 default: 1322 new_asoc->c.my_ttag = asoc->c.my_vtag; 1323 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1324 break; 1325 } 1326 1327 /* Other parameters for the endpoint SHOULD be copied from the 1328 * existing parameters of the association (e.g. number of 1329 * outbound streams) into the INIT ACK and cookie. 1330 */ 1331 new_asoc->rwnd = asoc->rwnd; 1332 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1333 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1334 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1335 } 1336 1337 /* 1338 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1339 * handling action. 1340 * 1341 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1342 * 1343 * Returns value representing action to be taken. These action values 1344 * correspond to Action/Description values in RFC 2960, Table 2. 1345 */ 1346 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1347 const struct sctp_association *asoc) 1348 { 1349 /* In this case, the peer may have restarted. */ 1350 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1351 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1352 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1353 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1354 return 'A'; 1355 1356 /* Collision case B. */ 1357 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1358 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1359 (0 == asoc->c.peer_vtag))) { 1360 return 'B'; 1361 } 1362 1363 /* Collision case D. */ 1364 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1365 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1366 return 'D'; 1367 1368 /* Collision case C. */ 1369 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1370 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1371 (0 == new_asoc->c.my_ttag) && 1372 (0 == new_asoc->c.peer_ttag)) 1373 return 'C'; 1374 1375 /* No match to any of the special cases; discard this packet. */ 1376 return 'E'; 1377 } 1378 1379 /* Common helper routine for both duplicate and simulataneous INIT 1380 * chunk handling. 1381 */ 1382 static sctp_disposition_t sctp_sf_do_unexpected_init( 1383 struct net *net, 1384 const struct sctp_endpoint *ep, 1385 const struct sctp_association *asoc, 1386 const sctp_subtype_t type, 1387 void *arg, sctp_cmd_seq_t *commands) 1388 { 1389 sctp_disposition_t retval; 1390 struct sctp_chunk *chunk = arg; 1391 struct sctp_chunk *repl; 1392 struct sctp_association *new_asoc; 1393 struct sctp_chunk *err_chunk; 1394 struct sctp_packet *packet; 1395 sctp_unrecognized_param_t *unk_param; 1396 int len; 1397 1398 /* 6.10 Bundling 1399 * An endpoint MUST NOT bundle INIT, INIT ACK or 1400 * SHUTDOWN COMPLETE with any other chunks. 1401 * 1402 * IG Section 2.11.2 1403 * Furthermore, we require that the receiver of an INIT chunk MUST 1404 * enforce these rules by silently discarding an arriving packet 1405 * with an INIT chunk that is bundled with other chunks. 1406 */ 1407 if (!chunk->singleton) 1408 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1409 1410 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1411 * Tag. 1412 */ 1413 if (chunk->sctp_hdr->vtag != 0) 1414 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1415 1416 /* Make sure that the INIT chunk has a valid length. 1417 * In this case, we generate a protocol violation since we have 1418 * an association established. 1419 */ 1420 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1421 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1422 commands); 1423 /* Grab the INIT header. */ 1424 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1425 1426 /* Tag the variable length parameters. */ 1427 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1428 1429 /* Verify the INIT chunk before processing it. */ 1430 err_chunk = NULL; 1431 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 1432 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1433 &err_chunk)) { 1434 /* This chunk contains fatal error. It is to be discarded. 1435 * Send an ABORT, with causes if there is any. 1436 */ 1437 if (err_chunk) { 1438 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1439 (__u8 *)(err_chunk->chunk_hdr) + 1440 sizeof(sctp_chunkhdr_t), 1441 ntohs(err_chunk->chunk_hdr->length) - 1442 sizeof(sctp_chunkhdr_t)); 1443 1444 if (packet) { 1445 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1446 SCTP_PACKET(packet)); 1447 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1448 retval = SCTP_DISPOSITION_CONSUME; 1449 } else { 1450 retval = SCTP_DISPOSITION_NOMEM; 1451 } 1452 goto cleanup; 1453 } else { 1454 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1455 commands); 1456 } 1457 } 1458 1459 /* 1460 * Other parameters for the endpoint SHOULD be copied from the 1461 * existing parameters of the association (e.g. number of 1462 * outbound streams) into the INIT ACK and cookie. 1463 * FIXME: We are copying parameters from the endpoint not the 1464 * association. 1465 */ 1466 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1467 if (!new_asoc) 1468 goto nomem; 1469 1470 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1471 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1472 goto nomem; 1473 1474 /* In the outbound INIT ACK the endpoint MUST copy its current 1475 * Verification Tag and Peers Verification tag into a reserved 1476 * place (local tie-tag and per tie-tag) within the state cookie. 1477 */ 1478 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1479 (sctp_init_chunk_t *)chunk->chunk_hdr, 1480 GFP_ATOMIC)) 1481 goto nomem; 1482 1483 /* Make sure no new addresses are being added during the 1484 * restart. Do not do this check for COOKIE-WAIT state, 1485 * since there are no peer addresses to check against. 1486 * Upon return an ABORT will have been sent if needed. 1487 */ 1488 if (!sctp_state(asoc, COOKIE_WAIT)) { 1489 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1490 commands)) { 1491 retval = SCTP_DISPOSITION_CONSUME; 1492 goto nomem_retval; 1493 } 1494 } 1495 1496 sctp_tietags_populate(new_asoc, asoc); 1497 1498 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1499 1500 /* If there are errors need to be reported for unknown parameters, 1501 * make sure to reserve enough room in the INIT ACK for them. 1502 */ 1503 len = 0; 1504 if (err_chunk) { 1505 len = ntohs(err_chunk->chunk_hdr->length) - 1506 sizeof(sctp_chunkhdr_t); 1507 } 1508 1509 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1510 if (!repl) 1511 goto nomem; 1512 1513 /* If there are errors need to be reported for unknown parameters, 1514 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1515 * parameter. 1516 */ 1517 if (err_chunk) { 1518 /* Get the "Unrecognized parameter" parameter(s) out of the 1519 * ERROR chunk generated by sctp_verify_init(). Since the 1520 * error cause code for "unknown parameter" and the 1521 * "Unrecognized parameter" type is the same, we can 1522 * construct the parameters in INIT ACK by copying the 1523 * ERROR causes over. 1524 */ 1525 unk_param = (sctp_unrecognized_param_t *) 1526 ((__u8 *)(err_chunk->chunk_hdr) + 1527 sizeof(sctp_chunkhdr_t)); 1528 /* Replace the cause code with the "Unrecognized parameter" 1529 * parameter type. 1530 */ 1531 sctp_addto_chunk(repl, len, unk_param); 1532 } 1533 1534 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1535 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1536 1537 /* 1538 * Note: After sending out INIT ACK with the State Cookie parameter, 1539 * "Z" MUST NOT allocate any resources for this new association. 1540 * Otherwise, "Z" will be vulnerable to resource attacks. 1541 */ 1542 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1543 retval = SCTP_DISPOSITION_CONSUME; 1544 1545 return retval; 1546 1547 nomem: 1548 retval = SCTP_DISPOSITION_NOMEM; 1549 nomem_retval: 1550 if (new_asoc) 1551 sctp_association_free(new_asoc); 1552 cleanup: 1553 if (err_chunk) 1554 sctp_chunk_free(err_chunk); 1555 return retval; 1556 } 1557 1558 /* 1559 * Handle simultaneous INIT. 1560 * This means we started an INIT and then we got an INIT request from 1561 * our peer. 1562 * 1563 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1564 * This usually indicates an initialization collision, i.e., each 1565 * endpoint is attempting, at about the same time, to establish an 1566 * association with the other endpoint. 1567 * 1568 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1569 * endpoint MUST respond with an INIT ACK using the same parameters it 1570 * sent in its original INIT chunk (including its Verification Tag, 1571 * unchanged). These original parameters are combined with those from the 1572 * newly received INIT chunk. The endpoint shall also generate a State 1573 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1574 * INIT to calculate the State Cookie. 1575 * 1576 * After that, the endpoint MUST NOT change its state, the T1-init 1577 * timer shall be left running and the corresponding TCB MUST NOT be 1578 * destroyed. The normal procedures for handling State Cookies when 1579 * a TCB exists will resolve the duplicate INITs to a single association. 1580 * 1581 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1582 * its Tie-Tags with the Tag information of itself and its peer (see 1583 * section 5.2.2 for a description of the Tie-Tags). 1584 * 1585 * Verification Tag: Not explicit, but an INIT can not have a valid 1586 * verification tag, so we skip the check. 1587 * 1588 * Inputs 1589 * (endpoint, asoc, chunk) 1590 * 1591 * Outputs 1592 * (asoc, reply_msg, msg_up, timers, counters) 1593 * 1594 * The return value is the disposition of the chunk. 1595 */ 1596 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1597 const struct sctp_endpoint *ep, 1598 const struct sctp_association *asoc, 1599 const sctp_subtype_t type, 1600 void *arg, 1601 sctp_cmd_seq_t *commands) 1602 { 1603 /* Call helper to do the real work for both simulataneous and 1604 * duplicate INIT chunk handling. 1605 */ 1606 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1607 } 1608 1609 /* 1610 * Handle duplicated INIT messages. These are usually delayed 1611 * restransmissions. 1612 * 1613 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1614 * COOKIE-ECHOED and COOKIE-WAIT 1615 * 1616 * Unless otherwise stated, upon reception of an unexpected INIT for 1617 * this association, the endpoint shall generate an INIT ACK with a 1618 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1619 * current Verification Tag and peer's Verification Tag into a reserved 1620 * place within the state cookie. We shall refer to these locations as 1621 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1622 * containing this INIT ACK MUST carry a Verification Tag value equal to 1623 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1624 * MUST contain a new Initiation Tag (randomly generated see Section 1625 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1626 * existing parameters of the association (e.g. number of outbound 1627 * streams) into the INIT ACK and cookie. 1628 * 1629 * After sending out the INIT ACK, the endpoint shall take no further 1630 * actions, i.e., the existing association, including its current state, 1631 * and the corresponding TCB MUST NOT be changed. 1632 * 1633 * Note: Only when a TCB exists and the association is not in a COOKIE- 1634 * WAIT state are the Tie-Tags populated. For a normal association INIT 1635 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1636 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1637 * State Cookie are populated as specified in section 5.2.1. 1638 * 1639 * Verification Tag: Not specified, but an INIT has no way of knowing 1640 * what the verification tag could be, so we ignore it. 1641 * 1642 * Inputs 1643 * (endpoint, asoc, chunk) 1644 * 1645 * Outputs 1646 * (asoc, reply_msg, msg_up, timers, counters) 1647 * 1648 * The return value is the disposition of the chunk. 1649 */ 1650 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1651 const struct sctp_endpoint *ep, 1652 const struct sctp_association *asoc, 1653 const sctp_subtype_t type, 1654 void *arg, 1655 sctp_cmd_seq_t *commands) 1656 { 1657 /* Call helper to do the real work for both simulataneous and 1658 * duplicate INIT chunk handling. 1659 */ 1660 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1661 } 1662 1663 1664 /* 1665 * Unexpected INIT-ACK handler. 1666 * 1667 * Section 5.2.3 1668 * If an INIT ACK received by an endpoint in any state other than the 1669 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1670 * An unexpected INIT ACK usually indicates the processing of an old or 1671 * duplicated INIT chunk. 1672 */ 1673 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1674 const struct sctp_endpoint *ep, 1675 const struct sctp_association *asoc, 1676 const sctp_subtype_t type, 1677 void *arg, sctp_cmd_seq_t *commands) 1678 { 1679 /* Per the above section, we'll discard the chunk if we have an 1680 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1681 */ 1682 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1683 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1684 else 1685 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1686 } 1687 1688 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1689 * 1690 * Section 5.2.4 1691 * A) In this case, the peer may have restarted. 1692 */ 1693 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1694 const struct sctp_endpoint *ep, 1695 const struct sctp_association *asoc, 1696 struct sctp_chunk *chunk, 1697 sctp_cmd_seq_t *commands, 1698 struct sctp_association *new_asoc) 1699 { 1700 sctp_init_chunk_t *peer_init; 1701 struct sctp_ulpevent *ev; 1702 struct sctp_chunk *repl; 1703 struct sctp_chunk *err; 1704 sctp_disposition_t disposition; 1705 1706 /* new_asoc is a brand-new association, so these are not yet 1707 * side effects--it is safe to run them here. 1708 */ 1709 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1710 1711 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1712 GFP_ATOMIC)) 1713 goto nomem; 1714 1715 /* Make sure no new addresses are being added during the 1716 * restart. Though this is a pretty complicated attack 1717 * since you'd have to get inside the cookie. 1718 */ 1719 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1720 return SCTP_DISPOSITION_CONSUME; 1721 } 1722 1723 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1724 * the peer has restarted (Action A), it MUST NOT setup a new 1725 * association but instead resend the SHUTDOWN ACK and send an ERROR 1726 * chunk with a "Cookie Received while Shutting Down" error cause to 1727 * its peer. 1728 */ 1729 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1730 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1731 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1732 chunk, commands); 1733 if (SCTP_DISPOSITION_NOMEM == disposition) 1734 goto nomem; 1735 1736 err = sctp_make_op_error(asoc, chunk, 1737 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1738 NULL, 0, 0); 1739 if (err) 1740 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1741 SCTP_CHUNK(err)); 1742 1743 return SCTP_DISPOSITION_CONSUME; 1744 } 1745 1746 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1747 * data. Consider the optional choice of resending of this data. 1748 */ 1749 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1750 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1751 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1752 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1753 1754 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1755 * and ASCONF-ACK cache. 1756 */ 1757 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1758 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1759 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1760 1761 repl = sctp_make_cookie_ack(new_asoc, chunk); 1762 if (!repl) 1763 goto nomem; 1764 1765 /* Report association restart to upper layer. */ 1766 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1767 new_asoc->c.sinit_num_ostreams, 1768 new_asoc->c.sinit_max_instreams, 1769 NULL, GFP_ATOMIC); 1770 if (!ev) 1771 goto nomem_ev; 1772 1773 /* Update the content of current association. */ 1774 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1775 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1776 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1777 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1778 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1779 return SCTP_DISPOSITION_CONSUME; 1780 1781 nomem_ev: 1782 sctp_chunk_free(repl); 1783 nomem: 1784 return SCTP_DISPOSITION_NOMEM; 1785 } 1786 1787 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1788 * 1789 * Section 5.2.4 1790 * B) In this case, both sides may be attempting to start an association 1791 * at about the same time but the peer endpoint started its INIT 1792 * after responding to the local endpoint's INIT 1793 */ 1794 /* This case represents an initialization collision. */ 1795 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1796 const struct sctp_endpoint *ep, 1797 const struct sctp_association *asoc, 1798 struct sctp_chunk *chunk, 1799 sctp_cmd_seq_t *commands, 1800 struct sctp_association *new_asoc) 1801 { 1802 sctp_init_chunk_t *peer_init; 1803 struct sctp_chunk *repl; 1804 1805 /* new_asoc is a brand-new association, so these are not yet 1806 * side effects--it is safe to run them here. 1807 */ 1808 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1809 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1810 GFP_ATOMIC)) 1811 goto nomem; 1812 1813 /* Update the content of current association. */ 1814 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1815 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1816 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1817 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1818 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1819 1820 repl = sctp_make_cookie_ack(new_asoc, chunk); 1821 if (!repl) 1822 goto nomem; 1823 1824 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1825 1826 /* RFC 2960 5.1 Normal Establishment of an Association 1827 * 1828 * D) IMPLEMENTATION NOTE: An implementation may choose to 1829 * send the Communication Up notification to the SCTP user 1830 * upon reception of a valid COOKIE ECHO chunk. 1831 * 1832 * Sadly, this needs to be implemented as a side-effect, because 1833 * we are not guaranteed to have set the association id of the real 1834 * association and so these notifications need to be delayed until 1835 * the association id is allocated. 1836 */ 1837 1838 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1839 1840 /* Sockets API Draft Section 5.3.1.6 1841 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1842 * delivers this notification to inform the application that of the 1843 * peers requested adaptation layer. 1844 * 1845 * This also needs to be done as a side effect for the same reason as 1846 * above. 1847 */ 1848 if (asoc->peer.adaptation_ind) 1849 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1850 1851 return SCTP_DISPOSITION_CONSUME; 1852 1853 nomem: 1854 return SCTP_DISPOSITION_NOMEM; 1855 } 1856 1857 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1858 * 1859 * Section 5.2.4 1860 * C) In this case, the local endpoint's cookie has arrived late. 1861 * Before it arrived, the local endpoint sent an INIT and received an 1862 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1863 * but a new tag of its own. 1864 */ 1865 /* This case represents an initialization collision. */ 1866 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1867 const struct sctp_endpoint *ep, 1868 const struct sctp_association *asoc, 1869 struct sctp_chunk *chunk, 1870 sctp_cmd_seq_t *commands, 1871 struct sctp_association *new_asoc) 1872 { 1873 /* The cookie should be silently discarded. 1874 * The endpoint SHOULD NOT change states and should leave 1875 * any timers running. 1876 */ 1877 return SCTP_DISPOSITION_DISCARD; 1878 } 1879 1880 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1881 * 1882 * Section 5.2.4 1883 * 1884 * D) When both local and remote tags match the endpoint should always 1885 * enter the ESTABLISHED state, if it has not already done so. 1886 */ 1887 /* This case represents an initialization collision. */ 1888 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1889 const struct sctp_endpoint *ep, 1890 const struct sctp_association *asoc, 1891 struct sctp_chunk *chunk, 1892 sctp_cmd_seq_t *commands, 1893 struct sctp_association *new_asoc) 1894 { 1895 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1896 struct sctp_chunk *repl; 1897 1898 /* Clarification from Implementor's Guide: 1899 * D) When both local and remote tags match the endpoint should 1900 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1901 * It should stop any cookie timer that may be running and send 1902 * a COOKIE ACK. 1903 */ 1904 1905 /* Don't accidentally move back into established state. */ 1906 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1907 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1908 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1909 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1910 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1911 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1912 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1913 SCTP_NULL()); 1914 1915 /* RFC 2960 5.1 Normal Establishment of an Association 1916 * 1917 * D) IMPLEMENTATION NOTE: An implementation may choose 1918 * to send the Communication Up notification to the 1919 * SCTP user upon reception of a valid COOKIE 1920 * ECHO chunk. 1921 */ 1922 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1923 SCTP_COMM_UP, 0, 1924 asoc->c.sinit_num_ostreams, 1925 asoc->c.sinit_max_instreams, 1926 NULL, GFP_ATOMIC); 1927 if (!ev) 1928 goto nomem; 1929 1930 /* Sockets API Draft Section 5.3.1.6 1931 * When a peer sends a Adaptation Layer Indication parameter, 1932 * SCTP delivers this notification to inform the application 1933 * that of the peers requested adaptation layer. 1934 */ 1935 if (asoc->peer.adaptation_ind) { 1936 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1937 GFP_ATOMIC); 1938 if (!ai_ev) 1939 goto nomem; 1940 1941 } 1942 } 1943 1944 repl = sctp_make_cookie_ack(new_asoc, chunk); 1945 if (!repl) 1946 goto nomem; 1947 1948 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1949 1950 if (ev) 1951 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1952 SCTP_ULPEVENT(ev)); 1953 if (ai_ev) 1954 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1955 SCTP_ULPEVENT(ai_ev)); 1956 1957 return SCTP_DISPOSITION_CONSUME; 1958 1959 nomem: 1960 if (ai_ev) 1961 sctp_ulpevent_free(ai_ev); 1962 if (ev) 1963 sctp_ulpevent_free(ev); 1964 return SCTP_DISPOSITION_NOMEM; 1965 } 1966 1967 /* 1968 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1969 * chunk was retransmitted and then delayed in the network. 1970 * 1971 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1972 * 1973 * Verification Tag: None. Do cookie validation. 1974 * 1975 * Inputs 1976 * (endpoint, asoc, chunk) 1977 * 1978 * Outputs 1979 * (asoc, reply_msg, msg_up, timers, counters) 1980 * 1981 * The return value is the disposition of the chunk. 1982 */ 1983 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 1984 const struct sctp_endpoint *ep, 1985 const struct sctp_association *asoc, 1986 const sctp_subtype_t type, 1987 void *arg, 1988 sctp_cmd_seq_t *commands) 1989 { 1990 sctp_disposition_t retval; 1991 struct sctp_chunk *chunk = arg; 1992 struct sctp_association *new_asoc; 1993 int error = 0; 1994 char action; 1995 struct sctp_chunk *err_chk_p; 1996 1997 /* Make sure that the chunk has a valid length from the protocol 1998 * perspective. In this case check to make sure we have at least 1999 * enough for the chunk header. Cookie length verification is 2000 * done later. 2001 */ 2002 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2003 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2004 commands); 2005 2006 /* "Decode" the chunk. We have no optional parameters so we 2007 * are in good shape. 2008 */ 2009 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2010 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2011 sizeof(sctp_chunkhdr_t))) 2012 goto nomem; 2013 2014 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2015 * of a duplicate COOKIE ECHO match the Verification Tags of the 2016 * current association, consider the State Cookie valid even if 2017 * the lifespan is exceeded. 2018 */ 2019 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2020 &err_chk_p); 2021 2022 /* FIXME: 2023 * If the re-build failed, what is the proper error path 2024 * from here? 2025 * 2026 * [We should abort the association. --piggy] 2027 */ 2028 if (!new_asoc) { 2029 /* FIXME: Several errors are possible. A bad cookie should 2030 * be silently discarded, but think about logging it too. 2031 */ 2032 switch (error) { 2033 case -SCTP_IERROR_NOMEM: 2034 goto nomem; 2035 2036 case -SCTP_IERROR_STALE_COOKIE: 2037 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2038 err_chk_p); 2039 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2040 case -SCTP_IERROR_BAD_SIG: 2041 default: 2042 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2043 } 2044 } 2045 2046 /* Compare the tie_tag in cookie with the verification tag of 2047 * current association. 2048 */ 2049 action = sctp_tietags_compare(new_asoc, asoc); 2050 2051 switch (action) { 2052 case 'A': /* Association restart. */ 2053 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2054 new_asoc); 2055 break; 2056 2057 case 'B': /* Collision case B. */ 2058 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2059 new_asoc); 2060 break; 2061 2062 case 'C': /* Collision case C. */ 2063 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2064 new_asoc); 2065 break; 2066 2067 case 'D': /* Collision case D. */ 2068 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2069 new_asoc); 2070 break; 2071 2072 default: /* Discard packet for all others. */ 2073 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2074 break; 2075 } 2076 2077 /* Delete the tempory new association. */ 2078 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2079 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2080 2081 /* Restore association pointer to provide SCTP command interpeter 2082 * with a valid context in case it needs to manipulate 2083 * the queues */ 2084 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2085 SCTP_ASOC((struct sctp_association *)asoc)); 2086 2087 return retval; 2088 2089 nomem: 2090 return SCTP_DISPOSITION_NOMEM; 2091 } 2092 2093 /* 2094 * Process an ABORT. (SHUTDOWN-PENDING state) 2095 * 2096 * See sctp_sf_do_9_1_abort(). 2097 */ 2098 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2099 struct net *net, 2100 const struct sctp_endpoint *ep, 2101 const struct sctp_association *asoc, 2102 const sctp_subtype_t type, 2103 void *arg, 2104 sctp_cmd_seq_t *commands) 2105 { 2106 struct sctp_chunk *chunk = arg; 2107 2108 if (!sctp_vtag_verify_either(chunk, asoc)) 2109 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2110 2111 /* Make sure that the ABORT chunk has a valid length. 2112 * Since this is an ABORT chunk, we have to discard it 2113 * because of the following text: 2114 * RFC 2960, Section 3.3.7 2115 * If an endpoint receives an ABORT with a format error or for an 2116 * association that doesn't exist, it MUST silently discard it. 2117 * Because the length is "invalid", we can't really discard just 2118 * as we do not know its true length. So, to be safe, discard the 2119 * packet. 2120 */ 2121 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2122 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2123 2124 /* ADD-IP: Special case for ABORT chunks 2125 * F4) One special consideration is that ABORT Chunks arriving 2126 * destined to the IP address being deleted MUST be 2127 * ignored (see Section 5.3.1 for further details). 2128 */ 2129 if (SCTP_ADDR_DEL == 2130 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2131 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2132 2133 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2134 } 2135 2136 /* 2137 * Process an ABORT. (SHUTDOWN-SENT state) 2138 * 2139 * See sctp_sf_do_9_1_abort(). 2140 */ 2141 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2142 const struct sctp_endpoint *ep, 2143 const struct sctp_association *asoc, 2144 const sctp_subtype_t type, 2145 void *arg, 2146 sctp_cmd_seq_t *commands) 2147 { 2148 struct sctp_chunk *chunk = arg; 2149 2150 if (!sctp_vtag_verify_either(chunk, asoc)) 2151 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2152 2153 /* Make sure that the ABORT chunk has a valid length. 2154 * Since this is an ABORT chunk, we have to discard it 2155 * because of the following text: 2156 * RFC 2960, Section 3.3.7 2157 * If an endpoint receives an ABORT with a format error or for an 2158 * association that doesn't exist, it MUST silently discard it. 2159 * Because the length is "invalid", we can't really discard just 2160 * as we do not know its true length. So, to be safe, discard the 2161 * packet. 2162 */ 2163 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2164 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2165 2166 /* ADD-IP: Special case for ABORT chunks 2167 * F4) One special consideration is that ABORT Chunks arriving 2168 * destined to the IP address being deleted MUST be 2169 * ignored (see Section 5.3.1 for further details). 2170 */ 2171 if (SCTP_ADDR_DEL == 2172 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2173 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2174 2175 /* Stop the T2-shutdown timer. */ 2176 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2177 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2178 2179 /* Stop the T5-shutdown guard timer. */ 2180 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2181 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2182 2183 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2184 } 2185 2186 /* 2187 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2188 * 2189 * See sctp_sf_do_9_1_abort(). 2190 */ 2191 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2192 struct net *net, 2193 const struct sctp_endpoint *ep, 2194 const struct sctp_association *asoc, 2195 const sctp_subtype_t type, 2196 void *arg, 2197 sctp_cmd_seq_t *commands) 2198 { 2199 /* The same T2 timer, so we should be able to use 2200 * common function with the SHUTDOWN-SENT state. 2201 */ 2202 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2203 } 2204 2205 /* 2206 * Handle an Error received in COOKIE_ECHOED state. 2207 * 2208 * Only handle the error type of stale COOKIE Error, the other errors will 2209 * be ignored. 2210 * 2211 * Inputs 2212 * (endpoint, asoc, chunk) 2213 * 2214 * Outputs 2215 * (asoc, reply_msg, msg_up, timers, counters) 2216 * 2217 * The return value is the disposition of the chunk. 2218 */ 2219 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2220 const struct sctp_endpoint *ep, 2221 const struct sctp_association *asoc, 2222 const sctp_subtype_t type, 2223 void *arg, 2224 sctp_cmd_seq_t *commands) 2225 { 2226 struct sctp_chunk *chunk = arg; 2227 sctp_errhdr_t *err; 2228 2229 if (!sctp_vtag_verify(chunk, asoc)) 2230 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2231 2232 /* Make sure that the ERROR chunk has a valid length. 2233 * The parameter walking depends on this as well. 2234 */ 2235 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2236 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2237 commands); 2238 2239 /* Process the error here */ 2240 /* FUTURE FIXME: When PR-SCTP related and other optional 2241 * parms are emitted, this will have to change to handle multiple 2242 * errors. 2243 */ 2244 sctp_walk_errors(err, chunk->chunk_hdr) { 2245 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2246 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2247 arg, commands); 2248 } 2249 2250 /* It is possible to have malformed error causes, and that 2251 * will cause us to end the walk early. However, since 2252 * we are discarding the packet, there should be no adverse 2253 * affects. 2254 */ 2255 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2256 } 2257 2258 /* 2259 * Handle a Stale COOKIE Error 2260 * 2261 * Section: 5.2.6 Handle Stale COOKIE Error 2262 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2263 * one of the following three alternatives. 2264 * ... 2265 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2266 * Preservative parameter requesting an extension to the lifetime of 2267 * the State Cookie. When calculating the time extension, an 2268 * implementation SHOULD use the RTT information measured based on the 2269 * previous COOKIE ECHO / ERROR exchange, and should add no more 2270 * than 1 second beyond the measured RTT, due to long State Cookie 2271 * lifetimes making the endpoint more subject to a replay attack. 2272 * 2273 * Verification Tag: Not explicit, but safe to ignore. 2274 * 2275 * Inputs 2276 * (endpoint, asoc, chunk) 2277 * 2278 * Outputs 2279 * (asoc, reply_msg, msg_up, timers, counters) 2280 * 2281 * The return value is the disposition of the chunk. 2282 */ 2283 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2284 const struct sctp_endpoint *ep, 2285 const struct sctp_association *asoc, 2286 const sctp_subtype_t type, 2287 void *arg, 2288 sctp_cmd_seq_t *commands) 2289 { 2290 struct sctp_chunk *chunk = arg; 2291 time_t stale; 2292 sctp_cookie_preserve_param_t bht; 2293 sctp_errhdr_t *err; 2294 struct sctp_chunk *reply; 2295 struct sctp_bind_addr *bp; 2296 int attempts = asoc->init_err_counter + 1; 2297 2298 if (attempts > asoc->max_init_attempts) { 2299 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2300 SCTP_ERROR(ETIMEDOUT)); 2301 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2302 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2303 return SCTP_DISPOSITION_DELETE_TCB; 2304 } 2305 2306 err = (sctp_errhdr_t *)(chunk->skb->data); 2307 2308 /* When calculating the time extension, an implementation 2309 * SHOULD use the RTT information measured based on the 2310 * previous COOKIE ECHO / ERROR exchange, and should add no 2311 * more than 1 second beyond the measured RTT, due to long 2312 * State Cookie lifetimes making the endpoint more subject to 2313 * a replay attack. 2314 * Measure of Staleness's unit is usec. (1/1000000 sec) 2315 * Suggested Cookie Life-span Increment's unit is msec. 2316 * (1/1000 sec) 2317 * In general, if you use the suggested cookie life, the value 2318 * found in the field of measure of staleness should be doubled 2319 * to give ample time to retransmit the new cookie and thus 2320 * yield a higher probability of success on the reattempt. 2321 */ 2322 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2323 stale = (stale * 2) / 1000; 2324 2325 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2326 bht.param_hdr.length = htons(sizeof(bht)); 2327 bht.lifespan_increment = htonl(stale); 2328 2329 /* Build that new INIT chunk. */ 2330 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2331 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2332 if (!reply) 2333 goto nomem; 2334 2335 sctp_addto_chunk(reply, sizeof(bht), &bht); 2336 2337 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2338 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2339 2340 /* Stop pending T3-rtx and heartbeat timers */ 2341 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2342 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2343 2344 /* Delete non-primary peer ip addresses since we are transitioning 2345 * back to the COOKIE-WAIT state 2346 */ 2347 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2348 2349 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2350 * resend 2351 */ 2352 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2353 SCTP_TRANSPORT(asoc->peer.primary_path)); 2354 2355 /* Cast away the const modifier, as we want to just 2356 * rerun it through as a sideffect. 2357 */ 2358 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2359 2360 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2361 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2362 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2363 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2364 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2365 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2366 2367 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2368 2369 return SCTP_DISPOSITION_CONSUME; 2370 2371 nomem: 2372 return SCTP_DISPOSITION_NOMEM; 2373 } 2374 2375 /* 2376 * Process an ABORT. 2377 * 2378 * Section: 9.1 2379 * After checking the Verification Tag, the receiving endpoint shall 2380 * remove the association from its record, and shall report the 2381 * termination to its upper layer. 2382 * 2383 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2384 * B) Rules for packet carrying ABORT: 2385 * 2386 * - The endpoint shall always fill in the Verification Tag field of the 2387 * outbound packet with the destination endpoint's tag value if it 2388 * is known. 2389 * 2390 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2391 * MUST follow the procedure described in Section 8.4. 2392 * 2393 * - The receiver MUST accept the packet if the Verification Tag 2394 * matches either its own tag, OR the tag of its peer. Otherwise, the 2395 * receiver MUST silently discard the packet and take no further 2396 * action. 2397 * 2398 * Inputs 2399 * (endpoint, asoc, chunk) 2400 * 2401 * Outputs 2402 * (asoc, reply_msg, msg_up, timers, counters) 2403 * 2404 * The return value is the disposition of the chunk. 2405 */ 2406 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2407 const struct sctp_endpoint *ep, 2408 const struct sctp_association *asoc, 2409 const sctp_subtype_t type, 2410 void *arg, 2411 sctp_cmd_seq_t *commands) 2412 { 2413 struct sctp_chunk *chunk = arg; 2414 2415 if (!sctp_vtag_verify_either(chunk, asoc)) 2416 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2417 2418 /* Make sure that the ABORT chunk has a valid length. 2419 * Since this is an ABORT chunk, we have to discard it 2420 * because of the following text: 2421 * RFC 2960, Section 3.3.7 2422 * If an endpoint receives an ABORT with a format error or for an 2423 * association that doesn't exist, it MUST silently discard it. 2424 * Because the length is "invalid", we can't really discard just 2425 * as we do not know its true length. So, to be safe, discard the 2426 * packet. 2427 */ 2428 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2429 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2430 2431 /* ADD-IP: Special case for ABORT chunks 2432 * F4) One special consideration is that ABORT Chunks arriving 2433 * destined to the IP address being deleted MUST be 2434 * ignored (see Section 5.3.1 for further details). 2435 */ 2436 if (SCTP_ADDR_DEL == 2437 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2438 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2439 2440 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2441 } 2442 2443 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2444 const struct sctp_endpoint *ep, 2445 const struct sctp_association *asoc, 2446 const sctp_subtype_t type, 2447 void *arg, 2448 sctp_cmd_seq_t *commands) 2449 { 2450 struct sctp_chunk *chunk = arg; 2451 unsigned int len; 2452 __be16 error = SCTP_ERROR_NO_ERROR; 2453 2454 /* See if we have an error cause code in the chunk. */ 2455 len = ntohs(chunk->chunk_hdr->length); 2456 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2457 2458 sctp_errhdr_t *err; 2459 sctp_walk_errors(err, chunk->chunk_hdr); 2460 if ((void *)err != (void *)chunk->chunk_end) 2461 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2462 2463 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2464 } 2465 2466 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2467 /* ASSOC_FAILED will DELETE_TCB. */ 2468 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2469 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2470 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2471 2472 return SCTP_DISPOSITION_ABORT; 2473 } 2474 2475 /* 2476 * Process an ABORT. (COOKIE-WAIT state) 2477 * 2478 * See sctp_sf_do_9_1_abort() above. 2479 */ 2480 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2481 const struct sctp_endpoint *ep, 2482 const struct sctp_association *asoc, 2483 const sctp_subtype_t type, 2484 void *arg, 2485 sctp_cmd_seq_t *commands) 2486 { 2487 struct sctp_chunk *chunk = arg; 2488 unsigned int len; 2489 __be16 error = SCTP_ERROR_NO_ERROR; 2490 2491 if (!sctp_vtag_verify_either(chunk, asoc)) 2492 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2493 2494 /* Make sure that the ABORT chunk has a valid length. 2495 * Since this is an ABORT chunk, we have to discard it 2496 * because of the following text: 2497 * RFC 2960, Section 3.3.7 2498 * If an endpoint receives an ABORT with a format error or for an 2499 * association that doesn't exist, it MUST silently discard it. 2500 * Because the length is "invalid", we can't really discard just 2501 * as we do not know its true length. So, to be safe, discard the 2502 * packet. 2503 */ 2504 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2505 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2506 2507 /* See if we have an error cause code in the chunk. */ 2508 len = ntohs(chunk->chunk_hdr->length); 2509 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2510 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2511 2512 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2513 chunk->transport); 2514 } 2515 2516 /* 2517 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2518 */ 2519 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2520 const struct sctp_endpoint *ep, 2521 const struct sctp_association *asoc, 2522 const sctp_subtype_t type, 2523 void *arg, 2524 sctp_cmd_seq_t *commands) 2525 { 2526 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2527 ENOPROTOOPT, asoc, 2528 (struct sctp_transport *)arg); 2529 } 2530 2531 /* 2532 * Process an ABORT. (COOKIE-ECHOED state) 2533 */ 2534 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2535 const struct sctp_endpoint *ep, 2536 const struct sctp_association *asoc, 2537 const sctp_subtype_t type, 2538 void *arg, 2539 sctp_cmd_seq_t *commands) 2540 { 2541 /* There is a single T1 timer, so we should be able to use 2542 * common function with the COOKIE-WAIT state. 2543 */ 2544 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2545 } 2546 2547 /* 2548 * Stop T1 timer and abort association with "INIT failed". 2549 * 2550 * This is common code called by several sctp_sf_*_abort() functions above. 2551 */ 2552 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2553 sctp_cmd_seq_t *commands, 2554 __be16 error, int sk_err, 2555 const struct sctp_association *asoc, 2556 struct sctp_transport *transport) 2557 { 2558 pr_debug("%s: ABORT received (INIT)\n", __func__); 2559 2560 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2561 SCTP_STATE(SCTP_STATE_CLOSED)); 2562 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2563 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2564 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2565 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2566 /* CMD_INIT_FAILED will DELETE_TCB. */ 2567 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2568 SCTP_PERR(error)); 2569 2570 return SCTP_DISPOSITION_ABORT; 2571 } 2572 2573 /* 2574 * sctp_sf_do_9_2_shut 2575 * 2576 * Section: 9.2 2577 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2578 * - enter the SHUTDOWN-RECEIVED state, 2579 * 2580 * - stop accepting new data from its SCTP user 2581 * 2582 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2583 * that all its outstanding DATA chunks have been received by the 2584 * SHUTDOWN sender. 2585 * 2586 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2587 * send a SHUTDOWN in response to a ULP request. And should discard 2588 * subsequent SHUTDOWN chunks. 2589 * 2590 * If there are still outstanding DATA chunks left, the SHUTDOWN 2591 * receiver shall continue to follow normal data transmission 2592 * procedures defined in Section 6 until all outstanding DATA chunks 2593 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2594 * new data from its SCTP user. 2595 * 2596 * Verification Tag: 8.5 Verification Tag [Normal verification] 2597 * 2598 * Inputs 2599 * (endpoint, asoc, chunk) 2600 * 2601 * Outputs 2602 * (asoc, reply_msg, msg_up, timers, counters) 2603 * 2604 * The return value is the disposition of the chunk. 2605 */ 2606 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2607 const struct sctp_endpoint *ep, 2608 const struct sctp_association *asoc, 2609 const sctp_subtype_t type, 2610 void *arg, 2611 sctp_cmd_seq_t *commands) 2612 { 2613 struct sctp_chunk *chunk = arg; 2614 sctp_shutdownhdr_t *sdh; 2615 sctp_disposition_t disposition; 2616 struct sctp_ulpevent *ev; 2617 __u32 ctsn; 2618 2619 if (!sctp_vtag_verify(chunk, asoc)) 2620 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2621 2622 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2623 if (!sctp_chunk_length_valid(chunk, 2624 sizeof(struct sctp_shutdown_chunk_t))) 2625 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2626 commands); 2627 2628 /* Convert the elaborate header. */ 2629 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2630 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2631 chunk->subh.shutdown_hdr = sdh; 2632 ctsn = ntohl(sdh->cum_tsn_ack); 2633 2634 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2635 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2636 asoc->ctsn_ack_point); 2637 2638 return SCTP_DISPOSITION_DISCARD; 2639 } 2640 2641 /* If Cumulative TSN Ack beyond the max tsn currently 2642 * send, terminating the association and respond to the 2643 * sender with an ABORT. 2644 */ 2645 if (!TSN_lt(ctsn, asoc->next_tsn)) 2646 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2647 2648 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2649 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2650 * inform the application that it should cease sending data. 2651 */ 2652 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2653 if (!ev) { 2654 disposition = SCTP_DISPOSITION_NOMEM; 2655 goto out; 2656 } 2657 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2658 2659 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2660 * - enter the SHUTDOWN-RECEIVED state, 2661 * - stop accepting new data from its SCTP user 2662 * 2663 * [This is implicit in the new state.] 2664 */ 2665 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2666 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2667 disposition = SCTP_DISPOSITION_CONSUME; 2668 2669 if (sctp_outq_is_empty(&asoc->outqueue)) { 2670 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2671 arg, commands); 2672 } 2673 2674 if (SCTP_DISPOSITION_NOMEM == disposition) 2675 goto out; 2676 2677 /* - verify, by checking the Cumulative TSN Ack field of the 2678 * chunk, that all its outstanding DATA chunks have been 2679 * received by the SHUTDOWN sender. 2680 */ 2681 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2682 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2683 2684 out: 2685 return disposition; 2686 } 2687 2688 /* 2689 * sctp_sf_do_9_2_shut_ctsn 2690 * 2691 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2692 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2693 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2694 * MUST be processed. 2695 */ 2696 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2697 const struct sctp_endpoint *ep, 2698 const struct sctp_association *asoc, 2699 const sctp_subtype_t type, 2700 void *arg, 2701 sctp_cmd_seq_t *commands) 2702 { 2703 struct sctp_chunk *chunk = arg; 2704 sctp_shutdownhdr_t *sdh; 2705 __u32 ctsn; 2706 2707 if (!sctp_vtag_verify(chunk, asoc)) 2708 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2709 2710 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2711 if (!sctp_chunk_length_valid(chunk, 2712 sizeof(struct sctp_shutdown_chunk_t))) 2713 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2714 commands); 2715 2716 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2717 ctsn = ntohl(sdh->cum_tsn_ack); 2718 2719 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2720 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2721 asoc->ctsn_ack_point); 2722 2723 return SCTP_DISPOSITION_DISCARD; 2724 } 2725 2726 /* If Cumulative TSN Ack beyond the max tsn currently 2727 * send, terminating the association and respond to the 2728 * sender with an ABORT. 2729 */ 2730 if (!TSN_lt(ctsn, asoc->next_tsn)) 2731 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2732 2733 /* verify, by checking the Cumulative TSN Ack field of the 2734 * chunk, that all its outstanding DATA chunks have been 2735 * received by the SHUTDOWN sender. 2736 */ 2737 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2738 SCTP_BE32(sdh->cum_tsn_ack)); 2739 2740 return SCTP_DISPOSITION_CONSUME; 2741 } 2742 2743 /* RFC 2960 9.2 2744 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2745 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2746 * transport addresses (either in the IP addresses or in the INIT chunk) 2747 * that belong to this association, it should discard the INIT chunk and 2748 * retransmit the SHUTDOWN ACK chunk. 2749 */ 2750 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2751 const struct sctp_endpoint *ep, 2752 const struct sctp_association *asoc, 2753 const sctp_subtype_t type, 2754 void *arg, 2755 sctp_cmd_seq_t *commands) 2756 { 2757 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2758 struct sctp_chunk *reply; 2759 2760 /* Make sure that the chunk has a valid length */ 2761 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2762 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2763 commands); 2764 2765 /* Since we are not going to really process this INIT, there 2766 * is no point in verifying chunk boundries. Just generate 2767 * the SHUTDOWN ACK. 2768 */ 2769 reply = sctp_make_shutdown_ack(asoc, chunk); 2770 if (NULL == reply) 2771 goto nomem; 2772 2773 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2774 * the T2-SHUTDOWN timer. 2775 */ 2776 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2777 2778 /* and restart the T2-shutdown timer. */ 2779 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2780 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2781 2782 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2783 2784 return SCTP_DISPOSITION_CONSUME; 2785 nomem: 2786 return SCTP_DISPOSITION_NOMEM; 2787 } 2788 2789 /* 2790 * sctp_sf_do_ecn_cwr 2791 * 2792 * Section: Appendix A: Explicit Congestion Notification 2793 * 2794 * CWR: 2795 * 2796 * RFC 2481 details a specific bit for a sender to send in the header of 2797 * its next outbound TCP segment to indicate to its peer that it has 2798 * reduced its congestion window. This is termed the CWR bit. For 2799 * SCTP the same indication is made by including the CWR chunk. 2800 * This chunk contains one data element, i.e. the TSN number that 2801 * was sent in the ECNE chunk. This element represents the lowest 2802 * TSN number in the datagram that was originally marked with the 2803 * CE bit. 2804 * 2805 * Verification Tag: 8.5 Verification Tag [Normal verification] 2806 * Inputs 2807 * (endpoint, asoc, chunk) 2808 * 2809 * Outputs 2810 * (asoc, reply_msg, msg_up, timers, counters) 2811 * 2812 * The return value is the disposition of the chunk. 2813 */ 2814 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2815 const struct sctp_endpoint *ep, 2816 const struct sctp_association *asoc, 2817 const sctp_subtype_t type, 2818 void *arg, 2819 sctp_cmd_seq_t *commands) 2820 { 2821 sctp_cwrhdr_t *cwr; 2822 struct sctp_chunk *chunk = arg; 2823 u32 lowest_tsn; 2824 2825 if (!sctp_vtag_verify(chunk, asoc)) 2826 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2827 2828 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2829 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2830 commands); 2831 2832 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2833 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2834 2835 lowest_tsn = ntohl(cwr->lowest_tsn); 2836 2837 /* Does this CWR ack the last sent congestion notification? */ 2838 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2839 /* Stop sending ECNE. */ 2840 sctp_add_cmd_sf(commands, 2841 SCTP_CMD_ECN_CWR, 2842 SCTP_U32(lowest_tsn)); 2843 } 2844 return SCTP_DISPOSITION_CONSUME; 2845 } 2846 2847 /* 2848 * sctp_sf_do_ecne 2849 * 2850 * Section: Appendix A: Explicit Congestion Notification 2851 * 2852 * ECN-Echo 2853 * 2854 * RFC 2481 details a specific bit for a receiver to send back in its 2855 * TCP acknowledgements to notify the sender of the Congestion 2856 * Experienced (CE) bit having arrived from the network. For SCTP this 2857 * same indication is made by including the ECNE chunk. This chunk 2858 * contains one data element, i.e. the lowest TSN associated with the IP 2859 * datagram marked with the CE bit..... 2860 * 2861 * Verification Tag: 8.5 Verification Tag [Normal verification] 2862 * Inputs 2863 * (endpoint, asoc, chunk) 2864 * 2865 * Outputs 2866 * (asoc, reply_msg, msg_up, timers, counters) 2867 * 2868 * The return value is the disposition of the chunk. 2869 */ 2870 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2871 const struct sctp_endpoint *ep, 2872 const struct sctp_association *asoc, 2873 const sctp_subtype_t type, 2874 void *arg, 2875 sctp_cmd_seq_t *commands) 2876 { 2877 sctp_ecnehdr_t *ecne; 2878 struct sctp_chunk *chunk = arg; 2879 2880 if (!sctp_vtag_verify(chunk, asoc)) 2881 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2882 2883 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2884 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2885 commands); 2886 2887 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2888 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2889 2890 /* If this is a newer ECNE than the last CWR packet we sent out */ 2891 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2892 SCTP_U32(ntohl(ecne->lowest_tsn))); 2893 2894 return SCTP_DISPOSITION_CONSUME; 2895 } 2896 2897 /* 2898 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2899 * 2900 * The SCTP endpoint MUST always acknowledge the reception of each valid 2901 * DATA chunk. 2902 * 2903 * The guidelines on delayed acknowledgement algorithm specified in 2904 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2905 * acknowledgement SHOULD be generated for at least every second packet 2906 * (not every second DATA chunk) received, and SHOULD be generated within 2907 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2908 * situations it may be beneficial for an SCTP transmitter to be more 2909 * conservative than the algorithms detailed in this document allow. 2910 * However, an SCTP transmitter MUST NOT be more aggressive than the 2911 * following algorithms allow. 2912 * 2913 * A SCTP receiver MUST NOT generate more than one SACK for every 2914 * incoming packet, other than to update the offered window as the 2915 * receiving application consumes new data. 2916 * 2917 * Verification Tag: 8.5 Verification Tag [Normal verification] 2918 * 2919 * Inputs 2920 * (endpoint, asoc, chunk) 2921 * 2922 * Outputs 2923 * (asoc, reply_msg, msg_up, timers, counters) 2924 * 2925 * The return value is the disposition of the chunk. 2926 */ 2927 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2928 const struct sctp_endpoint *ep, 2929 const struct sctp_association *asoc, 2930 const sctp_subtype_t type, 2931 void *arg, 2932 sctp_cmd_seq_t *commands) 2933 { 2934 struct sctp_chunk *chunk = arg; 2935 sctp_arg_t force = SCTP_NOFORCE(); 2936 int error; 2937 2938 if (!sctp_vtag_verify(chunk, asoc)) { 2939 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2940 SCTP_NULL()); 2941 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2942 } 2943 2944 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2945 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2946 commands); 2947 2948 error = sctp_eat_data(asoc, chunk, commands); 2949 switch (error) { 2950 case SCTP_IERROR_NO_ERROR: 2951 break; 2952 case SCTP_IERROR_HIGH_TSN: 2953 case SCTP_IERROR_BAD_STREAM: 2954 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2955 goto discard_noforce; 2956 case SCTP_IERROR_DUP_TSN: 2957 case SCTP_IERROR_IGNORE_TSN: 2958 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2959 goto discard_force; 2960 case SCTP_IERROR_NO_DATA: 2961 goto consume; 2962 case SCTP_IERROR_PROTO_VIOLATION: 2963 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 2964 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2965 default: 2966 BUG(); 2967 } 2968 2969 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2970 force = SCTP_FORCE(); 2971 2972 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 2973 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2974 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2975 } 2976 2977 /* If this is the last chunk in a packet, we need to count it 2978 * toward sack generation. Note that we need to SACK every 2979 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2980 * THEM. We elect to NOT generate SACK's if the chunk fails 2981 * the verification tag test. 2982 * 2983 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2984 * 2985 * The SCTP endpoint MUST always acknowledge the reception of 2986 * each valid DATA chunk. 2987 * 2988 * The guidelines on delayed acknowledgement algorithm 2989 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2990 * Specifically, an acknowledgement SHOULD be generated for at 2991 * least every second packet (not every second DATA chunk) 2992 * received, and SHOULD be generated within 200 ms of the 2993 * arrival of any unacknowledged DATA chunk. In some 2994 * situations it may be beneficial for an SCTP transmitter to 2995 * be more conservative than the algorithms detailed in this 2996 * document allow. However, an SCTP transmitter MUST NOT be 2997 * more aggressive than the following algorithms allow. 2998 */ 2999 if (chunk->end_of_packet) 3000 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3001 3002 return SCTP_DISPOSITION_CONSUME; 3003 3004 discard_force: 3005 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3006 * 3007 * When a packet arrives with duplicate DATA chunk(s) and with 3008 * no new DATA chunk(s), the endpoint MUST immediately send a 3009 * SACK with no delay. If a packet arrives with duplicate 3010 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3011 * MAY immediately send a SACK. Normally receipt of duplicate 3012 * DATA chunks will occur when the original SACK chunk was lost 3013 * and the peer's RTO has expired. The duplicate TSN number(s) 3014 * SHOULD be reported in the SACK as duplicate. 3015 */ 3016 /* In our case, we split the MAY SACK advice up whether or not 3017 * the last chunk is a duplicate.' 3018 */ 3019 if (chunk->end_of_packet) 3020 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3021 return SCTP_DISPOSITION_DISCARD; 3022 3023 discard_noforce: 3024 if (chunk->end_of_packet) 3025 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3026 3027 return SCTP_DISPOSITION_DISCARD; 3028 consume: 3029 return SCTP_DISPOSITION_CONSUME; 3030 3031 } 3032 3033 /* 3034 * sctp_sf_eat_data_fast_4_4 3035 * 3036 * Section: 4 (4) 3037 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3038 * DATA chunks without delay. 3039 * 3040 * Verification Tag: 8.5 Verification Tag [Normal verification] 3041 * Inputs 3042 * (endpoint, asoc, chunk) 3043 * 3044 * Outputs 3045 * (asoc, reply_msg, msg_up, timers, counters) 3046 * 3047 * The return value is the disposition of the chunk. 3048 */ 3049 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3050 const struct sctp_endpoint *ep, 3051 const struct sctp_association *asoc, 3052 const sctp_subtype_t type, 3053 void *arg, 3054 sctp_cmd_seq_t *commands) 3055 { 3056 struct sctp_chunk *chunk = arg; 3057 int error; 3058 3059 if (!sctp_vtag_verify(chunk, asoc)) { 3060 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3061 SCTP_NULL()); 3062 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3063 } 3064 3065 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3066 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3067 commands); 3068 3069 error = sctp_eat_data(asoc, chunk, commands); 3070 switch (error) { 3071 case SCTP_IERROR_NO_ERROR: 3072 case SCTP_IERROR_HIGH_TSN: 3073 case SCTP_IERROR_DUP_TSN: 3074 case SCTP_IERROR_IGNORE_TSN: 3075 case SCTP_IERROR_BAD_STREAM: 3076 break; 3077 case SCTP_IERROR_NO_DATA: 3078 goto consume; 3079 case SCTP_IERROR_PROTO_VIOLATION: 3080 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3081 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3082 default: 3083 BUG(); 3084 } 3085 3086 /* Go a head and force a SACK, since we are shutting down. */ 3087 3088 /* Implementor's Guide. 3089 * 3090 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3091 * respond to each received packet containing one or more DATA chunk(s) 3092 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3093 */ 3094 if (chunk->end_of_packet) { 3095 /* We must delay the chunk creation since the cumulative 3096 * TSN has not been updated yet. 3097 */ 3098 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3099 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3100 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3101 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3102 } 3103 3104 consume: 3105 return SCTP_DISPOSITION_CONSUME; 3106 } 3107 3108 /* 3109 * Section: 6.2 Processing a Received SACK 3110 * D) Any time a SACK arrives, the endpoint performs the following: 3111 * 3112 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3113 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3114 * increasing, a SACK whose Cumulative TSN Ack is less than the 3115 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3116 * 3117 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3118 * of bytes still outstanding after processing the Cumulative TSN Ack 3119 * and the Gap Ack Blocks. 3120 * 3121 * iii) If the SACK is missing a TSN that was previously 3122 * acknowledged via a Gap Ack Block (e.g., the data receiver 3123 * reneged on the data), then mark the corresponding DATA chunk 3124 * as available for retransmit: Mark it as missing for fast 3125 * retransmit as described in Section 7.2.4 and if no retransmit 3126 * timer is running for the destination address to which the DATA 3127 * chunk was originally transmitted, then T3-rtx is started for 3128 * that destination address. 3129 * 3130 * Verification Tag: 8.5 Verification Tag [Normal verification] 3131 * 3132 * Inputs 3133 * (endpoint, asoc, chunk) 3134 * 3135 * Outputs 3136 * (asoc, reply_msg, msg_up, timers, counters) 3137 * 3138 * The return value is the disposition of the chunk. 3139 */ 3140 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3141 const struct sctp_endpoint *ep, 3142 const struct sctp_association *asoc, 3143 const sctp_subtype_t type, 3144 void *arg, 3145 sctp_cmd_seq_t *commands) 3146 { 3147 struct sctp_chunk *chunk = arg; 3148 sctp_sackhdr_t *sackh; 3149 __u32 ctsn; 3150 3151 if (!sctp_vtag_verify(chunk, asoc)) 3152 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3153 3154 /* Make sure that the SACK chunk has a valid length. */ 3155 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3156 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3157 commands); 3158 3159 /* Pull the SACK chunk from the data buffer */ 3160 sackh = sctp_sm_pull_sack(chunk); 3161 /* Was this a bogus SACK? */ 3162 if (!sackh) 3163 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3164 chunk->subh.sack_hdr = sackh; 3165 ctsn = ntohl(sackh->cum_tsn_ack); 3166 3167 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3168 * Ack Point, then drop the SACK. Since Cumulative TSN 3169 * Ack is monotonically increasing, a SACK whose 3170 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3171 * Point indicates an out-of-order SACK. 3172 */ 3173 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3174 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3175 asoc->ctsn_ack_point); 3176 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, commands); 3685 ((struct sctp_association *)asoc)->new_transport = NULL; 3686 } 3687 3688 return SCTP_DISPOSITION_CONSUME; 3689 } 3690 3691 /* 3692 * ADDIP Section 4.3 General rules for address manipulation 3693 * When building TLV parameters for the ASCONF Chunk that will add or 3694 * delete IP addresses the D0 to D13 rules should be applied: 3695 */ 3696 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3697 const struct sctp_endpoint *ep, 3698 const struct sctp_association *asoc, 3699 const sctp_subtype_t type, void *arg, 3700 sctp_cmd_seq_t *commands) 3701 { 3702 struct sctp_chunk *asconf_ack = arg; 3703 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3704 struct sctp_chunk *abort; 3705 struct sctp_paramhdr *err_param = NULL; 3706 sctp_addiphdr_t *addip_hdr; 3707 __u32 sent_serial, rcvd_serial; 3708 3709 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3710 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3711 SCTP_NULL()); 3712 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3713 } 3714 3715 /* ADD-IP, Section 4.1.2: 3716 * This chunk MUST be sent in an authenticated way by using 3717 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3718 * is received unauthenticated it MUST be silently discarded as 3719 * described in [I-D.ietf-tsvwg-sctp-auth]. 3720 */ 3721 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3722 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3723 3724 /* Make sure that the ADDIP chunk has a valid length. */ 3725 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3726 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3727 commands); 3728 3729 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3730 rcvd_serial = ntohl(addip_hdr->serial); 3731 3732 /* Verify the ASCONF-ACK chunk before processing it. */ 3733 if (!sctp_verify_asconf(asoc, 3734 (sctp_paramhdr_t *)addip_hdr->params, 3735 (void *)asconf_ack->chunk_end, 3736 &err_param)) 3737 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3738 (void *)err_param, commands); 3739 3740 if (last_asconf) { 3741 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3742 sent_serial = ntohl(addip_hdr->serial); 3743 } else { 3744 sent_serial = asoc->addip_serial - 1; 3745 } 3746 3747 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3748 * equal to the next serial number to be used but no ASCONF chunk is 3749 * outstanding the endpoint MUST ABORT the association. Note that a 3750 * sequence number is greater than if it is no more than 2^^31-1 3751 * larger than the current sequence number (using serial arithmetic). 3752 */ 3753 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3754 !(asoc->addip_last_asconf)) { 3755 abort = sctp_make_abort(asoc, asconf_ack, 3756 sizeof(sctp_errhdr_t)); 3757 if (abort) { 3758 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3759 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3760 SCTP_CHUNK(abort)); 3761 } 3762 /* We are going to ABORT, so we might as well stop 3763 * processing the rest of the chunks in the packet. 3764 */ 3765 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3766 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3767 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3768 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3769 SCTP_ERROR(ECONNABORTED)); 3770 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3771 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3772 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3773 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3774 return SCTP_DISPOSITION_ABORT; 3775 } 3776 3777 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3778 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3779 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3780 3781 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3782 asconf_ack)) { 3783 /* Successfully processed ASCONF_ACK. We can 3784 * release the next asconf if we have one. 3785 */ 3786 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3787 SCTP_NULL()); 3788 return SCTP_DISPOSITION_CONSUME; 3789 } 3790 3791 abort = sctp_make_abort(asoc, asconf_ack, 3792 sizeof(sctp_errhdr_t)); 3793 if (abort) { 3794 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3795 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3796 SCTP_CHUNK(abort)); 3797 } 3798 /* We are going to ABORT, so we might as well stop 3799 * processing the rest of the chunks in the packet. 3800 */ 3801 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 3802 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3803 SCTP_ERROR(ECONNABORTED)); 3804 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3805 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3806 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3807 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3808 return SCTP_DISPOSITION_ABORT; 3809 } 3810 3811 return SCTP_DISPOSITION_DISCARD; 3812 } 3813 3814 /* 3815 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3816 * 3817 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3818 * its cumulative TSN point to the value carried in the FORWARD TSN 3819 * chunk, and then MUST further advance its cumulative TSN point locally 3820 * if possible. 3821 * After the above processing, the data receiver MUST stop reporting any 3822 * missing TSNs earlier than or equal to the new cumulative TSN point. 3823 * 3824 * Verification Tag: 8.5 Verification Tag [Normal verification] 3825 * 3826 * The return value is the disposition of the chunk. 3827 */ 3828 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3829 const struct sctp_endpoint *ep, 3830 const struct sctp_association *asoc, 3831 const sctp_subtype_t type, 3832 void *arg, 3833 sctp_cmd_seq_t *commands) 3834 { 3835 struct sctp_chunk *chunk = arg; 3836 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3837 struct sctp_fwdtsn_skip *skip; 3838 __u16 len; 3839 __u32 tsn; 3840 3841 if (!sctp_vtag_verify(chunk, asoc)) { 3842 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3843 SCTP_NULL()); 3844 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3845 } 3846 3847 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3848 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3849 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3850 commands); 3851 3852 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3853 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3854 len = ntohs(chunk->chunk_hdr->length); 3855 len -= sizeof(struct sctp_chunkhdr); 3856 skb_pull(chunk->skb, len); 3857 3858 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3859 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3860 3861 /* The TSN is too high--silently discard the chunk and count on it 3862 * getting retransmitted later. 3863 */ 3864 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3865 goto discard_noforce; 3866 3867 /* Silently discard the chunk if stream-id is not valid */ 3868 sctp_walk_fwdtsn(skip, chunk) { 3869 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3870 goto discard_noforce; 3871 } 3872 3873 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3874 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3875 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3876 SCTP_CHUNK(chunk)); 3877 3878 /* Count this as receiving DATA. */ 3879 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3880 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3881 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3882 } 3883 3884 /* FIXME: For now send a SACK, but DATA processing may 3885 * send another. 3886 */ 3887 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3888 3889 return SCTP_DISPOSITION_CONSUME; 3890 3891 discard_noforce: 3892 return SCTP_DISPOSITION_DISCARD; 3893 } 3894 3895 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3896 struct net *net, 3897 const struct sctp_endpoint *ep, 3898 const struct sctp_association *asoc, 3899 const sctp_subtype_t type, 3900 void *arg, 3901 sctp_cmd_seq_t *commands) 3902 { 3903 struct sctp_chunk *chunk = arg; 3904 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3905 struct sctp_fwdtsn_skip *skip; 3906 __u16 len; 3907 __u32 tsn; 3908 3909 if (!sctp_vtag_verify(chunk, asoc)) { 3910 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3911 SCTP_NULL()); 3912 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3913 } 3914 3915 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3916 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3917 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3918 commands); 3919 3920 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3921 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3922 len = ntohs(chunk->chunk_hdr->length); 3923 len -= sizeof(struct sctp_chunkhdr); 3924 skb_pull(chunk->skb, len); 3925 3926 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3927 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3928 3929 /* The TSN is too high--silently discard the chunk and count on it 3930 * getting retransmitted later. 3931 */ 3932 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3933 goto gen_shutdown; 3934 3935 /* Silently discard the chunk if stream-id is not valid */ 3936 sctp_walk_fwdtsn(skip, chunk) { 3937 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3938 goto gen_shutdown; 3939 } 3940 3941 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3942 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3943 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3944 SCTP_CHUNK(chunk)); 3945 3946 /* Go a head and force a SACK, since we are shutting down. */ 3947 gen_shutdown: 3948 /* Implementor's Guide. 3949 * 3950 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3951 * respond to each received packet containing one or more DATA chunk(s) 3952 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3953 */ 3954 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3955 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3956 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3957 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3958 3959 return SCTP_DISPOSITION_CONSUME; 3960 } 3961 3962 /* 3963 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3964 * 3965 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3966 * Identifier field. If this algorithm was not specified by the 3967 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3968 * during association setup, the AUTH chunk and all chunks after it MUST 3969 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3970 * defined in Section 4.1. 3971 * 3972 * If an endpoint with no shared key receives a Shared Key Identifier 3973 * other than 0, it MUST silently discard all authenticated chunks. If 3974 * the endpoint has at least one endpoint pair shared key for the peer, 3975 * it MUST use the key specified by the Shared Key Identifier if a 3976 * key has been configured for that Shared Key Identifier. If no 3977 * endpoint pair shared key has been configured for that Shared Key 3978 * Identifier, all authenticated chunks MUST be silently discarded. 3979 * 3980 * Verification Tag: 8.5 Verification Tag [Normal verification] 3981 * 3982 * The return value is the disposition of the chunk. 3983 */ 3984 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 3985 const struct sctp_endpoint *ep, 3986 const struct sctp_association *asoc, 3987 const sctp_subtype_t type, 3988 struct sctp_chunk *chunk) 3989 { 3990 struct sctp_authhdr *auth_hdr; 3991 struct sctp_hmac *hmac; 3992 unsigned int sig_len; 3993 __u16 key_id; 3994 __u8 *save_digest; 3995 __u8 *digest; 3996 3997 /* Pull in the auth header, so we can do some more verification */ 3998 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 3999 chunk->subh.auth_hdr = auth_hdr; 4000 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4001 4002 /* Make sure that we support the HMAC algorithm from the auth 4003 * chunk. 4004 */ 4005 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4006 return SCTP_IERROR_AUTH_BAD_HMAC; 4007 4008 /* Make sure that the provided shared key identifier has been 4009 * configured 4010 */ 4011 key_id = ntohs(auth_hdr->shkey_id); 4012 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4013 return SCTP_IERROR_AUTH_BAD_KEYID; 4014 4015 4016 /* Make sure that the length of the signature matches what 4017 * we expect. 4018 */ 4019 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4020 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4021 if (sig_len != hmac->hmac_len) 4022 return SCTP_IERROR_PROTO_VIOLATION; 4023 4024 /* Now that we've done validation checks, we can compute and 4025 * verify the hmac. The steps involved are: 4026 * 1. Save the digest from the chunk. 4027 * 2. Zero out the digest in the chunk. 4028 * 3. Compute the new digest 4029 * 4. Compare saved and new digests. 4030 */ 4031 digest = auth_hdr->hmac; 4032 skb_pull(chunk->skb, sig_len); 4033 4034 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4035 if (!save_digest) 4036 goto nomem; 4037 4038 memset(digest, 0, sig_len); 4039 4040 sctp_auth_calculate_hmac(asoc, chunk->skb, 4041 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4042 GFP_ATOMIC); 4043 4044 /* Discard the packet if the digests do not match */ 4045 if (memcmp(save_digest, digest, sig_len)) { 4046 kfree(save_digest); 4047 return SCTP_IERROR_BAD_SIG; 4048 } 4049 4050 kfree(save_digest); 4051 chunk->auth = 1; 4052 4053 return SCTP_IERROR_NO_ERROR; 4054 nomem: 4055 return SCTP_IERROR_NOMEM; 4056 } 4057 4058 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4059 const struct sctp_endpoint *ep, 4060 const struct sctp_association *asoc, 4061 const sctp_subtype_t type, 4062 void *arg, 4063 sctp_cmd_seq_t *commands) 4064 { 4065 struct sctp_authhdr *auth_hdr; 4066 struct sctp_chunk *chunk = arg; 4067 struct sctp_chunk *err_chunk; 4068 sctp_ierror_t error; 4069 4070 /* Make sure that the peer has AUTH capable */ 4071 if (!asoc->peer.auth_capable) 4072 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4073 4074 if (!sctp_vtag_verify(chunk, asoc)) { 4075 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4076 SCTP_NULL()); 4077 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4078 } 4079 4080 /* Make sure that the AUTH chunk has valid length. */ 4081 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4082 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4083 commands); 4084 4085 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4086 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4087 switch (error) { 4088 case SCTP_IERROR_AUTH_BAD_HMAC: 4089 /* Generate the ERROR chunk and discard the rest 4090 * of the packet 4091 */ 4092 err_chunk = sctp_make_op_error(asoc, chunk, 4093 SCTP_ERROR_UNSUP_HMAC, 4094 &auth_hdr->hmac_id, 4095 sizeof(__u16), 0); 4096 if (err_chunk) { 4097 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4098 SCTP_CHUNK(err_chunk)); 4099 } 4100 /* Fall Through */ 4101 case SCTP_IERROR_AUTH_BAD_KEYID: 4102 case SCTP_IERROR_BAD_SIG: 4103 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4104 4105 case SCTP_IERROR_PROTO_VIOLATION: 4106 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4107 commands); 4108 4109 case SCTP_IERROR_NOMEM: 4110 return SCTP_DISPOSITION_NOMEM; 4111 4112 default: /* Prevent gcc warnings */ 4113 break; 4114 } 4115 4116 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4117 struct sctp_ulpevent *ev; 4118 4119 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4120 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4121 4122 if (!ev) 4123 return -ENOMEM; 4124 4125 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4126 SCTP_ULPEVENT(ev)); 4127 } 4128 4129 return SCTP_DISPOSITION_CONSUME; 4130 } 4131 4132 /* 4133 * Process an unknown chunk. 4134 * 4135 * Section: 3.2. Also, 2.1 in the implementor's guide. 4136 * 4137 * Chunk Types are encoded such that the highest-order two bits specify 4138 * the action that must be taken if the processing endpoint does not 4139 * recognize the Chunk Type. 4140 * 4141 * 00 - Stop processing this SCTP packet and discard it, do not process 4142 * any further chunks within it. 4143 * 4144 * 01 - Stop processing this SCTP packet and discard it, do not process 4145 * any further chunks within it, and report the unrecognized 4146 * chunk in an 'Unrecognized Chunk Type'. 4147 * 4148 * 10 - Skip this chunk and continue processing. 4149 * 4150 * 11 - Skip this chunk and continue processing, but report in an ERROR 4151 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4152 * 4153 * The return value is the disposition of the chunk. 4154 */ 4155 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4156 const struct sctp_endpoint *ep, 4157 const struct sctp_association *asoc, 4158 const sctp_subtype_t type, 4159 void *arg, 4160 sctp_cmd_seq_t *commands) 4161 { 4162 struct sctp_chunk *unk_chunk = arg; 4163 struct sctp_chunk *err_chunk; 4164 sctp_chunkhdr_t *hdr; 4165 4166 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4167 4168 if (!sctp_vtag_verify(unk_chunk, asoc)) 4169 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4170 4171 /* Make sure that the chunk has a valid length. 4172 * Since we don't know the chunk type, we use a general 4173 * chunkhdr structure to make a comparison. 4174 */ 4175 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4176 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4177 commands); 4178 4179 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4180 case SCTP_CID_ACTION_DISCARD: 4181 /* Discard the packet. */ 4182 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4183 break; 4184 case SCTP_CID_ACTION_DISCARD_ERR: 4185 /* Generate an ERROR chunk as response. */ 4186 hdr = unk_chunk->chunk_hdr; 4187 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4188 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4189 WORD_ROUND(ntohs(hdr->length)), 4190 0); 4191 if (err_chunk) { 4192 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4193 SCTP_CHUNK(err_chunk)); 4194 } 4195 4196 /* Discard the packet. */ 4197 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4198 return SCTP_DISPOSITION_CONSUME; 4199 break; 4200 case SCTP_CID_ACTION_SKIP: 4201 /* Skip the chunk. */ 4202 return SCTP_DISPOSITION_DISCARD; 4203 break; 4204 case SCTP_CID_ACTION_SKIP_ERR: 4205 /* Generate an ERROR chunk as response. */ 4206 hdr = unk_chunk->chunk_hdr; 4207 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4208 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4209 WORD_ROUND(ntohs(hdr->length)), 4210 0); 4211 if (err_chunk) { 4212 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4213 SCTP_CHUNK(err_chunk)); 4214 } 4215 /* Skip the chunk. */ 4216 return SCTP_DISPOSITION_CONSUME; 4217 break; 4218 default: 4219 break; 4220 } 4221 4222 return SCTP_DISPOSITION_DISCARD; 4223 } 4224 4225 /* 4226 * Discard the chunk. 4227 * 4228 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4229 * [Too numerous to mention...] 4230 * Verification Tag: No verification needed. 4231 * Inputs 4232 * (endpoint, asoc, chunk) 4233 * 4234 * Outputs 4235 * (asoc, reply_msg, msg_up, timers, counters) 4236 * 4237 * The return value is the disposition of the chunk. 4238 */ 4239 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4240 const struct sctp_endpoint *ep, 4241 const struct sctp_association *asoc, 4242 const sctp_subtype_t type, 4243 void *arg, 4244 sctp_cmd_seq_t *commands) 4245 { 4246 struct sctp_chunk *chunk = arg; 4247 4248 /* Make sure that the chunk has a valid length. 4249 * Since we don't know the chunk type, we use a general 4250 * chunkhdr structure to make a comparison. 4251 */ 4252 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4253 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4254 commands); 4255 4256 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4257 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 /* Choose transport for INIT. */ 4634 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4635 SCTP_CHUNK(repl)); 4636 4637 /* Cast away the const modifier, as we want to just 4638 * rerun it through as a sideffect. 4639 */ 4640 my_asoc = (struct sctp_association *)asoc; 4641 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 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 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5186 type.primitive); 5187 5188 return SCTP_DISPOSITION_DISCARD; 5189 } 5190 5191 /*************************************************************************** 5192 * These are the state functions for the OTHER events. 5193 ***************************************************************************/ 5194 5195 /* 5196 * When the SCTP stack has no more user data to send or retransmit, this 5197 * notification is given to the user. Also, at the time when a user app 5198 * subscribes to this event, if there is no data to be sent or 5199 * retransmit, the stack will immediately send up this notification. 5200 */ 5201 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5202 struct net *net, 5203 const struct sctp_endpoint *ep, 5204 const struct sctp_association *asoc, 5205 const sctp_subtype_t type, 5206 void *arg, 5207 sctp_cmd_seq_t *commands) 5208 { 5209 struct sctp_ulpevent *event; 5210 5211 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5212 if (!event) 5213 return SCTP_DISPOSITION_NOMEM; 5214 5215 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5216 5217 return SCTP_DISPOSITION_CONSUME; 5218 } 5219 5220 /* 5221 * Start the shutdown negotiation. 5222 * 5223 * From Section 9.2: 5224 * Once all its outstanding data has been acknowledged, the endpoint 5225 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5226 * TSN Ack field the last sequential TSN it has received from the peer. 5227 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5228 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5229 * with the updated last sequential TSN received from its peer. 5230 * 5231 * The return value is the disposition. 5232 */ 5233 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5234 struct net *net, 5235 const struct sctp_endpoint *ep, 5236 const struct sctp_association *asoc, 5237 const sctp_subtype_t type, 5238 void *arg, 5239 sctp_cmd_seq_t *commands) 5240 { 5241 struct sctp_chunk *reply; 5242 5243 /* Once all its outstanding data has been acknowledged, the 5244 * endpoint shall send a SHUTDOWN chunk to its peer including 5245 * in the Cumulative TSN Ack field the last sequential TSN it 5246 * has received from the peer. 5247 */ 5248 reply = sctp_make_shutdown(asoc, NULL); 5249 if (!reply) 5250 goto nomem; 5251 5252 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5253 * T2-shutdown timer. 5254 */ 5255 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5256 5257 /* It shall then start the T2-shutdown timer */ 5258 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5259 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5260 5261 /* RFC 4960 Section 9.2 5262 * The sender of the SHUTDOWN MAY also start an overall guard timer 5263 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5264 */ 5265 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5266 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5267 5268 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5269 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5270 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5271 5272 /* and enter the SHUTDOWN-SENT state. */ 5273 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5274 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5275 5276 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5277 * 5278 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5279 * or SHUTDOWN-ACK. 5280 */ 5281 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5282 5283 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5284 5285 return SCTP_DISPOSITION_CONSUME; 5286 5287 nomem: 5288 return SCTP_DISPOSITION_NOMEM; 5289 } 5290 5291 /* 5292 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5293 * 5294 * From Section 9.2: 5295 * 5296 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5297 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5298 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5299 * endpoint must re-send the SHUTDOWN ACK. 5300 * 5301 * The return value is the disposition. 5302 */ 5303 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5304 struct net *net, 5305 const struct sctp_endpoint *ep, 5306 const struct sctp_association *asoc, 5307 const sctp_subtype_t type, 5308 void *arg, 5309 sctp_cmd_seq_t *commands) 5310 { 5311 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5312 struct sctp_chunk *reply; 5313 5314 /* There are 2 ways of getting here: 5315 * 1) called in response to a SHUTDOWN chunk 5316 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5317 * 5318 * For the case (2), the arg parameter is set to NULL. We need 5319 * to check that we have a chunk before accessing it's fields. 5320 */ 5321 if (chunk) { 5322 if (!sctp_vtag_verify(chunk, asoc)) 5323 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5324 5325 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5326 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5327 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5328 commands); 5329 } 5330 5331 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5332 * shall send a SHUTDOWN ACK ... 5333 */ 5334 reply = sctp_make_shutdown_ack(asoc, chunk); 5335 if (!reply) 5336 goto nomem; 5337 5338 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5339 * the T2-shutdown timer. 5340 */ 5341 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5342 5343 /* and start/restart a T2-shutdown timer of its own, */ 5344 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5345 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5346 5347 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5348 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5349 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5350 5351 /* Enter the SHUTDOWN-ACK-SENT state. */ 5352 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5353 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5354 5355 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5356 * 5357 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5358 * or SHUTDOWN-ACK. 5359 */ 5360 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5361 5362 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5363 5364 return SCTP_DISPOSITION_CONSUME; 5365 5366 nomem: 5367 return SCTP_DISPOSITION_NOMEM; 5368 } 5369 5370 /* 5371 * Ignore the event defined as other 5372 * 5373 * The return value is the disposition of the event. 5374 */ 5375 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5376 const struct sctp_endpoint *ep, 5377 const struct sctp_association *asoc, 5378 const sctp_subtype_t type, 5379 void *arg, 5380 sctp_cmd_seq_t *commands) 5381 { 5382 pr_debug("%s: the event other type:%d is ignored\n", 5383 __func__, type.other); 5384 5385 return SCTP_DISPOSITION_DISCARD; 5386 } 5387 5388 /************************************************************ 5389 * These are the state functions for handling timeout events. 5390 ************************************************************/ 5391 5392 /* 5393 * RTX Timeout 5394 * 5395 * Section: 6.3.3 Handle T3-rtx Expiration 5396 * 5397 * Whenever the retransmission timer T3-rtx expires for a destination 5398 * address, do the following: 5399 * [See below] 5400 * 5401 * The return value is the disposition of the chunk. 5402 */ 5403 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5404 const struct sctp_endpoint *ep, 5405 const struct sctp_association *asoc, 5406 const sctp_subtype_t type, 5407 void *arg, 5408 sctp_cmd_seq_t *commands) 5409 { 5410 struct sctp_transport *transport = arg; 5411 5412 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5413 5414 if (asoc->overall_error_count >= asoc->max_retrans) { 5415 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5416 /* 5417 * We are here likely because the receiver had its rwnd 5418 * closed for a while and we have not been able to 5419 * transmit the locally queued data within the maximum 5420 * retransmission attempts limit. Start the T5 5421 * shutdown guard timer to give the receiver one last 5422 * chance and some additional time to recover before 5423 * aborting. 5424 */ 5425 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5426 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5427 } else { 5428 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5429 SCTP_ERROR(ETIMEDOUT)); 5430 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5431 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5432 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5433 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5434 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5435 return SCTP_DISPOSITION_DELETE_TCB; 5436 } 5437 } 5438 5439 /* E1) For the destination address for which the timer 5440 * expires, adjust its ssthresh with rules defined in Section 5441 * 7.2.3 and set the cwnd <- MTU. 5442 */ 5443 5444 /* E2) For the destination address for which the timer 5445 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5446 * maximum value discussed in rule C7 above (RTO.max) may be 5447 * used to provide an upper bound to this doubling operation. 5448 */ 5449 5450 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5451 * outstanding DATA chunks for the address for which the 5452 * T3-rtx has expired will fit into a single packet, subject 5453 * to the MTU constraint for the path corresponding to the 5454 * destination transport address to which the retransmission 5455 * is being sent (this may be different from the address for 5456 * which the timer expires [see Section 6.4]). Call this 5457 * value K. Bundle and retransmit those K DATA chunks in a 5458 * single packet to the destination endpoint. 5459 * 5460 * Note: Any DATA chunks that were sent to the address for 5461 * which the T3-rtx timer expired but did not fit in one MTU 5462 * (rule E3 above), should be marked for retransmission and 5463 * sent as soon as cwnd allows (normally when a SACK arrives). 5464 */ 5465 5466 /* Do some failure management (Section 8.2). */ 5467 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5468 5469 /* NB: Rules E4 and F1 are implicit in R1. */ 5470 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5471 5472 return SCTP_DISPOSITION_CONSUME; 5473 } 5474 5475 /* 5476 * Generate delayed SACK on timeout 5477 * 5478 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5479 * 5480 * The guidelines on delayed acknowledgement algorithm specified in 5481 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5482 * acknowledgement SHOULD be generated for at least every second packet 5483 * (not every second DATA chunk) received, and SHOULD be generated 5484 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5485 * some situations it may be beneficial for an SCTP transmitter to be 5486 * more conservative than the algorithms detailed in this document 5487 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5488 * the following algorithms allow. 5489 */ 5490 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5491 const struct sctp_endpoint *ep, 5492 const struct sctp_association *asoc, 5493 const sctp_subtype_t type, 5494 void *arg, 5495 sctp_cmd_seq_t *commands) 5496 { 5497 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5498 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5499 return SCTP_DISPOSITION_CONSUME; 5500 } 5501 5502 /* 5503 * sctp_sf_t1_init_timer_expire 5504 * 5505 * Section: 4 Note: 2 5506 * Verification Tag: 5507 * Inputs 5508 * (endpoint, asoc) 5509 * 5510 * RFC 2960 Section 4 Notes 5511 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5512 * and re-start the T1-init timer without changing state. This MUST 5513 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5514 * endpoint MUST abort the initialization process and report the 5515 * error to SCTP user. 5516 * 5517 * Outputs 5518 * (timers, events) 5519 * 5520 */ 5521 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5522 const struct sctp_endpoint *ep, 5523 const struct sctp_association *asoc, 5524 const sctp_subtype_t type, 5525 void *arg, 5526 sctp_cmd_seq_t *commands) 5527 { 5528 struct sctp_chunk *repl = NULL; 5529 struct sctp_bind_addr *bp; 5530 int attempts = asoc->init_err_counter + 1; 5531 5532 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5533 5534 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5535 5536 if (attempts <= asoc->max_init_attempts) { 5537 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5538 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5539 if (!repl) 5540 return SCTP_DISPOSITION_NOMEM; 5541 5542 /* Choose transport for INIT. */ 5543 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5544 SCTP_CHUNK(repl)); 5545 5546 /* Issue a sideeffect to do the needed accounting. */ 5547 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5548 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5549 5550 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5551 } else { 5552 pr_debug("%s: giving up on INIT, attempts:%d " 5553 "max_init_attempts:%d\n", __func__, attempts, 5554 asoc->max_init_attempts); 5555 5556 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5557 SCTP_ERROR(ETIMEDOUT)); 5558 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5559 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5560 return SCTP_DISPOSITION_DELETE_TCB; 5561 } 5562 5563 return SCTP_DISPOSITION_CONSUME; 5564 } 5565 5566 /* 5567 * sctp_sf_t1_cookie_timer_expire 5568 * 5569 * Section: 4 Note: 2 5570 * Verification Tag: 5571 * Inputs 5572 * (endpoint, asoc) 5573 * 5574 * RFC 2960 Section 4 Notes 5575 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5576 * COOKIE ECHO and re-start the T1-cookie timer without changing 5577 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5578 * After that, the endpoint MUST abort the initialization process and 5579 * report the error to SCTP user. 5580 * 5581 * Outputs 5582 * (timers, events) 5583 * 5584 */ 5585 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5586 const struct sctp_endpoint *ep, 5587 const struct sctp_association *asoc, 5588 const sctp_subtype_t type, 5589 void *arg, 5590 sctp_cmd_seq_t *commands) 5591 { 5592 struct sctp_chunk *repl = NULL; 5593 int attempts = asoc->init_err_counter + 1; 5594 5595 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5596 5597 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5598 5599 if (attempts <= asoc->max_init_attempts) { 5600 repl = sctp_make_cookie_echo(asoc, NULL); 5601 if (!repl) 5602 return SCTP_DISPOSITION_NOMEM; 5603 5604 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5605 SCTP_CHUNK(repl)); 5606 /* Issue a sideeffect to do the needed accounting. */ 5607 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5608 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5609 5610 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5611 } else { 5612 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5613 SCTP_ERROR(ETIMEDOUT)); 5614 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5615 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5616 return SCTP_DISPOSITION_DELETE_TCB; 5617 } 5618 5619 return SCTP_DISPOSITION_CONSUME; 5620 } 5621 5622 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5623 * with the updated last sequential TSN received from its peer. 5624 * 5625 * An endpoint should limit the number of retransmissions of the 5626 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5627 * If this threshold is exceeded the endpoint should destroy the TCB and 5628 * MUST report the peer endpoint unreachable to the upper layer (and 5629 * thus the association enters the CLOSED state). The reception of any 5630 * packet from its peer (i.e. as the peer sends all of its queued DATA 5631 * chunks) should clear the endpoint's retransmission count and restart 5632 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5633 * all of its queued DATA chunks that have not yet been sent. 5634 */ 5635 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5636 const struct sctp_endpoint *ep, 5637 const struct sctp_association *asoc, 5638 const sctp_subtype_t type, 5639 void *arg, 5640 sctp_cmd_seq_t *commands) 5641 { 5642 struct sctp_chunk *reply = NULL; 5643 5644 pr_debug("%s: timer T2 expired\n", __func__); 5645 5646 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5647 5648 ((struct sctp_association *)asoc)->shutdown_retries++; 5649 5650 if (asoc->overall_error_count >= asoc->max_retrans) { 5651 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5652 SCTP_ERROR(ETIMEDOUT)); 5653 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5654 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5655 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5656 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5657 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5658 return SCTP_DISPOSITION_DELETE_TCB; 5659 } 5660 5661 switch (asoc->state) { 5662 case SCTP_STATE_SHUTDOWN_SENT: 5663 reply = sctp_make_shutdown(asoc, NULL); 5664 break; 5665 5666 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5667 reply = sctp_make_shutdown_ack(asoc, NULL); 5668 break; 5669 5670 default: 5671 BUG(); 5672 break; 5673 } 5674 5675 if (!reply) 5676 goto nomem; 5677 5678 /* Do some failure management (Section 8.2). 5679 * If we remove the transport an SHUTDOWN was last sent to, don't 5680 * do failure management. 5681 */ 5682 if (asoc->shutdown_last_sent_to) 5683 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5684 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5685 5686 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5687 * the T2-shutdown timer. 5688 */ 5689 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5690 5691 /* Restart the T2-shutdown timer. */ 5692 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5693 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5694 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5695 return SCTP_DISPOSITION_CONSUME; 5696 5697 nomem: 5698 return SCTP_DISPOSITION_NOMEM; 5699 } 5700 5701 /* 5702 * ADDIP Section 4.1 ASCONF CHunk Procedures 5703 * If the T4 RTO timer expires the endpoint should do B1 to B5 5704 */ 5705 sctp_disposition_t sctp_sf_t4_timer_expire( 5706 struct net *net, 5707 const struct sctp_endpoint *ep, 5708 const struct sctp_association *asoc, 5709 const sctp_subtype_t type, 5710 void *arg, 5711 sctp_cmd_seq_t *commands) 5712 { 5713 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5714 struct sctp_transport *transport = chunk->transport; 5715 5716 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5717 5718 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5719 * detection on the appropriate destination address as defined in 5720 * RFC2960 [5] section 8.1 and 8.2. 5721 */ 5722 if (transport) 5723 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5724 SCTP_TRANSPORT(transport)); 5725 5726 /* Reconfig T4 timer and transport. */ 5727 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5728 5729 /* ADDIP 4.1 B2) Increment the association error counters and perform 5730 * endpoint failure detection on the association as defined in 5731 * RFC2960 [5] section 8.1 and 8.2. 5732 * association error counter is incremented in SCTP_CMD_STRIKE. 5733 */ 5734 if (asoc->overall_error_count >= asoc->max_retrans) { 5735 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5736 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5737 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5738 SCTP_ERROR(ETIMEDOUT)); 5739 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5740 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5741 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5742 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5743 return SCTP_DISPOSITION_ABORT; 5744 } 5745 5746 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5747 * the ASCONF chunk was sent by doubling the RTO timer value. 5748 * This is done in SCTP_CMD_STRIKE. 5749 */ 5750 5751 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5752 * choose an alternate destination address (please refer to RFC2960 5753 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5754 * chunk, it MUST be the same (including its serial number) as the last 5755 * ASCONF sent. 5756 */ 5757 sctp_chunk_hold(asoc->addip_last_asconf); 5758 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5759 SCTP_CHUNK(asoc->addip_last_asconf)); 5760 5761 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5762 * destination is selected, then the RTO used will be that of the new 5763 * destination address. 5764 */ 5765 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5766 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5767 5768 return SCTP_DISPOSITION_CONSUME; 5769 } 5770 5771 /* sctpimpguide-05 Section 2.12.2 5772 * The sender of the SHUTDOWN MAY also start an overall guard timer 5773 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5774 * At the expiration of this timer the sender SHOULD abort the association 5775 * by sending an ABORT chunk. 5776 */ 5777 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5778 const struct sctp_endpoint *ep, 5779 const struct sctp_association *asoc, 5780 const sctp_subtype_t type, 5781 void *arg, 5782 sctp_cmd_seq_t *commands) 5783 { 5784 struct sctp_chunk *reply = NULL; 5785 5786 pr_debug("%s: timer T5 expired\n", __func__); 5787 5788 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5789 5790 reply = sctp_make_abort(asoc, NULL, 0); 5791 if (!reply) 5792 goto nomem; 5793 5794 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5795 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5796 SCTP_ERROR(ETIMEDOUT)); 5797 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5798 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5799 5800 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5801 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5802 5803 return SCTP_DISPOSITION_DELETE_TCB; 5804 nomem: 5805 return SCTP_DISPOSITION_NOMEM; 5806 } 5807 5808 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5809 * the association is automatically closed by starting the shutdown process. 5810 * The work that needs to be done is same as when SHUTDOWN is initiated by 5811 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5812 */ 5813 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5814 struct net *net, 5815 const struct sctp_endpoint *ep, 5816 const struct sctp_association *asoc, 5817 const sctp_subtype_t type, 5818 void *arg, 5819 sctp_cmd_seq_t *commands) 5820 { 5821 int disposition; 5822 5823 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5824 5825 /* From 9.2 Shutdown of an Association 5826 * Upon receipt of the SHUTDOWN primitive from its upper 5827 * layer, the endpoint enters SHUTDOWN-PENDING state and 5828 * remains there until all outstanding data has been 5829 * acknowledged by its peer. The endpoint accepts no new data 5830 * from its upper layer, but retransmits data to the far end 5831 * if necessary to fill gaps. 5832 */ 5833 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5834 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5835 5836 disposition = SCTP_DISPOSITION_CONSUME; 5837 if (sctp_outq_is_empty(&asoc->outqueue)) { 5838 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5839 arg, commands); 5840 } 5841 return disposition; 5842 } 5843 5844 /***************************************************************************** 5845 * These are sa state functions which could apply to all types of events. 5846 ****************************************************************************/ 5847 5848 /* 5849 * This table entry is not implemented. 5850 * 5851 * Inputs 5852 * (endpoint, asoc, chunk) 5853 * 5854 * The return value is the disposition of the chunk. 5855 */ 5856 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5857 const struct sctp_endpoint *ep, 5858 const struct sctp_association *asoc, 5859 const sctp_subtype_t type, 5860 void *arg, 5861 sctp_cmd_seq_t *commands) 5862 { 5863 return SCTP_DISPOSITION_NOT_IMPL; 5864 } 5865 5866 /* 5867 * This table entry represents a bug. 5868 * 5869 * Inputs 5870 * (endpoint, asoc, chunk) 5871 * 5872 * The return value is the disposition of the chunk. 5873 */ 5874 sctp_disposition_t sctp_sf_bug(struct net *net, 5875 const struct sctp_endpoint *ep, 5876 const struct sctp_association *asoc, 5877 const sctp_subtype_t type, 5878 void *arg, 5879 sctp_cmd_seq_t *commands) 5880 { 5881 return SCTP_DISPOSITION_BUG; 5882 } 5883 5884 /* 5885 * This table entry represents the firing of a timer in the wrong state. 5886 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5887 * when the association is in the wrong state. This event should 5888 * be ignored, so as to prevent any rearming of the timer. 5889 * 5890 * Inputs 5891 * (endpoint, asoc, chunk) 5892 * 5893 * The return value is the disposition of the chunk. 5894 */ 5895 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5896 const struct sctp_endpoint *ep, 5897 const struct sctp_association *asoc, 5898 const sctp_subtype_t type, 5899 void *arg, 5900 sctp_cmd_seq_t *commands) 5901 { 5902 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 5903 5904 return SCTP_DISPOSITION_CONSUME; 5905 } 5906 5907 /******************************************************************** 5908 * 2nd Level Abstractions 5909 ********************************************************************/ 5910 5911 /* Pull the SACK chunk based on the SACK header. */ 5912 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5913 { 5914 struct sctp_sackhdr *sack; 5915 unsigned int len; 5916 __u16 num_blocks; 5917 __u16 num_dup_tsns; 5918 5919 /* Protect ourselves from reading too far into 5920 * the skb from a bogus sender. 5921 */ 5922 sack = (struct sctp_sackhdr *) chunk->skb->data; 5923 5924 num_blocks = ntohs(sack->num_gap_ack_blocks); 5925 num_dup_tsns = ntohs(sack->num_dup_tsns); 5926 len = sizeof(struct sctp_sackhdr); 5927 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5928 if (len > chunk->skb->len) 5929 return NULL; 5930 5931 skb_pull(chunk->skb, len); 5932 5933 return sack; 5934 } 5935 5936 /* Create an ABORT packet to be sent as a response, with the specified 5937 * error causes. 5938 */ 5939 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 5940 const struct sctp_endpoint *ep, 5941 const struct sctp_association *asoc, 5942 struct sctp_chunk *chunk, 5943 const void *payload, 5944 size_t paylen) 5945 { 5946 struct sctp_packet *packet; 5947 struct sctp_chunk *abort; 5948 5949 packet = sctp_ootb_pkt_new(net, asoc, chunk); 5950 5951 if (packet) { 5952 /* Make an ABORT. 5953 * The T bit will be set if the asoc is NULL. 5954 */ 5955 abort = sctp_make_abort(asoc, chunk, paylen); 5956 if (!abort) { 5957 sctp_ootb_pkt_free(packet); 5958 return NULL; 5959 } 5960 5961 /* Reflect vtag if T-Bit is set */ 5962 if (sctp_test_T_bit(abort)) 5963 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5964 5965 /* Add specified error causes, i.e., payload, to the 5966 * end of the chunk. 5967 */ 5968 sctp_addto_chunk(abort, paylen, payload); 5969 5970 /* Set the skb to the belonging sock for accounting. */ 5971 abort->skb->sk = ep->base.sk; 5972 5973 sctp_packet_append_chunk(packet, abort); 5974 5975 } 5976 5977 return packet; 5978 } 5979 5980 /* Allocate a packet for responding in the OOTB conditions. */ 5981 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 5982 const struct sctp_association *asoc, 5983 const struct sctp_chunk *chunk) 5984 { 5985 struct sctp_packet *packet; 5986 struct sctp_transport *transport; 5987 __u16 sport; 5988 __u16 dport; 5989 __u32 vtag; 5990 5991 /* Get the source and destination port from the inbound packet. */ 5992 sport = ntohs(chunk->sctp_hdr->dest); 5993 dport = ntohs(chunk->sctp_hdr->source); 5994 5995 /* The V-tag is going to be the same as the inbound packet if no 5996 * association exists, otherwise, use the peer's vtag. 5997 */ 5998 if (asoc) { 5999 /* Special case the INIT-ACK as there is no peer's vtag 6000 * yet. 6001 */ 6002 switch (chunk->chunk_hdr->type) { 6003 case SCTP_CID_INIT_ACK: 6004 { 6005 sctp_initack_chunk_t *initack; 6006 6007 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6008 vtag = ntohl(initack->init_hdr.init_tag); 6009 break; 6010 } 6011 default: 6012 vtag = asoc->peer.i.init_tag; 6013 break; 6014 } 6015 } else { 6016 /* Special case the INIT and stale COOKIE_ECHO as there is no 6017 * vtag yet. 6018 */ 6019 switch (chunk->chunk_hdr->type) { 6020 case SCTP_CID_INIT: 6021 { 6022 sctp_init_chunk_t *init; 6023 6024 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6025 vtag = ntohl(init->init_hdr.init_tag); 6026 break; 6027 } 6028 default: 6029 vtag = ntohl(chunk->sctp_hdr->vtag); 6030 break; 6031 } 6032 } 6033 6034 /* Make a transport for the bucket, Eliza... */ 6035 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6036 if (!transport) 6037 goto nomem; 6038 6039 /* Cache a route for the transport with the chunk's destination as 6040 * the source address. 6041 */ 6042 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6043 sctp_sk(net->sctp.ctl_sock)); 6044 6045 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 6046 packet = sctp_packet_config(packet, vtag, 0); 6047 6048 return packet; 6049 6050 nomem: 6051 return NULL; 6052 } 6053 6054 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6055 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6056 { 6057 sctp_transport_free(packet->transport); 6058 } 6059 6060 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6061 static void sctp_send_stale_cookie_err(struct net *net, 6062 const struct sctp_endpoint *ep, 6063 const struct sctp_association *asoc, 6064 const struct sctp_chunk *chunk, 6065 sctp_cmd_seq_t *commands, 6066 struct sctp_chunk *err_chunk) 6067 { 6068 struct sctp_packet *packet; 6069 6070 if (err_chunk) { 6071 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6072 if (packet) { 6073 struct sctp_signed_cookie *cookie; 6074 6075 /* Override the OOTB vtag from the cookie. */ 6076 cookie = chunk->subh.cookie_hdr; 6077 packet->vtag = cookie->c.peer_vtag; 6078 6079 /* Set the skb to the belonging sock for accounting. */ 6080 err_chunk->skb->sk = ep->base.sk; 6081 sctp_packet_append_chunk(packet, err_chunk); 6082 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6083 SCTP_PACKET(packet)); 6084 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6085 } else 6086 sctp_chunk_free (err_chunk); 6087 } 6088 } 6089 6090 6091 /* Process a data chunk */ 6092 static int sctp_eat_data(const struct sctp_association *asoc, 6093 struct sctp_chunk *chunk, 6094 sctp_cmd_seq_t *commands) 6095 { 6096 sctp_datahdr_t *data_hdr; 6097 struct sctp_chunk *err; 6098 size_t datalen; 6099 sctp_verb_t deliver; 6100 int tmp; 6101 __u32 tsn; 6102 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6103 struct sock *sk = asoc->base.sk; 6104 struct net *net = sock_net(sk); 6105 u16 ssn; 6106 u16 sid; 6107 u8 ordered = 0; 6108 6109 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6110 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6111 6112 tsn = ntohl(data_hdr->tsn); 6113 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6114 6115 /* ASSERT: Now skb->data is really the user data. */ 6116 6117 /* Process ECN based congestion. 6118 * 6119 * Since the chunk structure is reused for all chunks within 6120 * a packet, we use ecn_ce_done to track if we've already 6121 * done CE processing for this packet. 6122 * 6123 * We need to do ECN processing even if we plan to discard the 6124 * chunk later. 6125 */ 6126 6127 if (!chunk->ecn_ce_done) { 6128 struct sctp_af *af; 6129 chunk->ecn_ce_done = 1; 6130 6131 af = sctp_get_af_specific( 6132 ipver2af(ip_hdr(chunk->skb)->version)); 6133 6134 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 6135 /* Do real work as sideffect. */ 6136 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6137 SCTP_U32(tsn)); 6138 } 6139 } 6140 6141 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6142 if (tmp < 0) { 6143 /* The TSN is too high--silently discard the chunk and 6144 * count on it getting retransmitted later. 6145 */ 6146 if (chunk->asoc) 6147 chunk->asoc->stats.outofseqtsns++; 6148 return SCTP_IERROR_HIGH_TSN; 6149 } else if (tmp > 0) { 6150 /* This is a duplicate. Record it. */ 6151 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6152 return SCTP_IERROR_DUP_TSN; 6153 } 6154 6155 /* This is a new TSN. */ 6156 6157 /* Discard if there is no room in the receive window. 6158 * Actually, allow a little bit of overflow (up to a MTU). 6159 */ 6160 datalen = ntohs(chunk->chunk_hdr->length); 6161 datalen -= sizeof(sctp_data_chunk_t); 6162 6163 deliver = SCTP_CMD_CHUNK_ULP; 6164 6165 /* Think about partial delivery. */ 6166 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6167 6168 /* Even if we don't accept this chunk there is 6169 * memory pressure. 6170 */ 6171 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6172 } 6173 6174 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6175 * seems a bit troublesome in that frag_point varies based on 6176 * PMTU. In cases, such as loopback, this might be a rather 6177 * large spill over. 6178 */ 6179 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6180 (datalen > asoc->rwnd + asoc->frag_point))) { 6181 6182 /* If this is the next TSN, consider reneging to make 6183 * room. Note: Playing nice with a confused sender. A 6184 * malicious sender can still eat up all our buffer 6185 * space and in the future we may want to detect and 6186 * do more drastic reneging. 6187 */ 6188 if (sctp_tsnmap_has_gap(map) && 6189 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6190 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6191 deliver = SCTP_CMD_RENEGE; 6192 } else { 6193 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6194 __func__, tsn, datalen, asoc->rwnd); 6195 6196 return SCTP_IERROR_IGNORE_TSN; 6197 } 6198 } 6199 6200 /* 6201 * Also try to renege to limit our memory usage in the event that 6202 * we are under memory pressure 6203 * If we can't renege, don't worry about it, the sk_rmem_schedule 6204 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6205 * memory usage too much 6206 */ 6207 if (*sk->sk_prot_creator->memory_pressure) { 6208 if (sctp_tsnmap_has_gap(map) && 6209 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6210 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6211 __func__, tsn); 6212 deliver = SCTP_CMD_RENEGE; 6213 } 6214 } 6215 6216 /* 6217 * Section 3.3.10.9 No User Data (9) 6218 * 6219 * Cause of error 6220 * --------------- 6221 * No User Data: This error cause is returned to the originator of a 6222 * DATA chunk if a received DATA chunk has no user data. 6223 */ 6224 if (unlikely(0 == datalen)) { 6225 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6226 if (err) { 6227 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6228 SCTP_CHUNK(err)); 6229 } 6230 /* We are going to ABORT, so we might as well stop 6231 * processing the rest of the chunks in the packet. 6232 */ 6233 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6234 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6235 SCTP_ERROR(ECONNABORTED)); 6236 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6237 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6238 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6239 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6240 return SCTP_IERROR_NO_DATA; 6241 } 6242 6243 chunk->data_accepted = 1; 6244 6245 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6246 * if we renege and the chunk arrives again. 6247 */ 6248 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6249 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6250 if (chunk->asoc) 6251 chunk->asoc->stats.iuodchunks++; 6252 } else { 6253 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6254 if (chunk->asoc) 6255 chunk->asoc->stats.iodchunks++; 6256 ordered = 1; 6257 } 6258 6259 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6260 * 6261 * If an endpoint receive a DATA chunk with an invalid stream 6262 * identifier, it shall acknowledge the reception of the DATA chunk 6263 * following the normal procedure, immediately send an ERROR chunk 6264 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6265 * and discard the DATA chunk. 6266 */ 6267 sid = ntohs(data_hdr->stream); 6268 if (sid >= asoc->c.sinit_max_instreams) { 6269 /* Mark tsn as received even though we drop it */ 6270 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6271 6272 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6273 &data_hdr->stream, 6274 sizeof(data_hdr->stream), 6275 sizeof(u16)); 6276 if (err) 6277 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6278 SCTP_CHUNK(err)); 6279 return SCTP_IERROR_BAD_STREAM; 6280 } 6281 6282 /* Check to see if the SSN is possible for this TSN. 6283 * The biggest gap we can record is 4K wide. Since SSNs wrap 6284 * at an unsigned short, there is no way that an SSN can 6285 * wrap and for a valid TSN. We can simply check if the current 6286 * SSN is smaller then the next expected one. If it is, it wrapped 6287 * and is invalid. 6288 */ 6289 ssn = ntohs(data_hdr->ssn); 6290 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6291 return SCTP_IERROR_PROTO_VIOLATION; 6292 } 6293 6294 /* Send the data up to the user. Note: Schedule the 6295 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6296 * chunk needs the updated rwnd. 6297 */ 6298 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6299 6300 return SCTP_IERROR_NO_ERROR; 6301 } 6302