1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 Intel Corp. 6 * Copyright (c) 2002 Nokia Corp. 7 * 8 * This is part of the SCTP Linux Kernel Implementation. 9 * 10 * These are the state functions for the state machine. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <linux-sctp@vger.kernel.org> 32 * 33 * Written or modified by: 34 * La Monte H.P. Yarroll <piggy@acm.org> 35 * Karl Knutson <karl@athena.chicago.il.us> 36 * Mathew Kotowsky <kotowsky@sctp.org> 37 * Sridhar Samudrala <samudrala@us.ibm.com> 38 * Jon Grimm <jgrimm@us.ibm.com> 39 * Hui Huang <hui.huang@nokia.com> 40 * Dajiang Zhang <dajiang.zhang@nokia.com> 41 * Daisy Chang <daisyc@us.ibm.com> 42 * Ardelle Fan <ardelle.fan@intel.com> 43 * Ryan Layer <rmlayer@us.ibm.com> 44 * Kevin Gao <kevin.gao@intel.com> 45 */ 46 47 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 48 49 #include <linux/types.h> 50 #include <linux/kernel.h> 51 #include <linux/ip.h> 52 #include <linux/ipv6.h> 53 #include <linux/net.h> 54 #include <linux/inet.h> 55 #include <linux/slab.h> 56 #include <net/sock.h> 57 #include <net/inet_ecn.h> 58 #include <linux/skbuff.h> 59 #include <net/sctp/sctp.h> 60 #include <net/sctp/sm.h> 61 #include <net/sctp/structs.h> 62 63 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 64 const struct sctp_endpoint *ep, 65 const struct sctp_association *asoc, 66 struct sctp_chunk *chunk, 67 const void *payload, 68 size_t paylen); 69 static int sctp_eat_data(const struct sctp_association *asoc, 70 struct sctp_chunk *chunk, 71 sctp_cmd_seq_t *commands); 72 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 73 const struct sctp_association *asoc, 74 const struct sctp_chunk *chunk); 75 static void sctp_send_stale_cookie_err(struct net *net, 76 const struct sctp_endpoint *ep, 77 const struct sctp_association *asoc, 78 const struct sctp_chunk *chunk, 79 sctp_cmd_seq_t *commands, 80 struct sctp_chunk *err_chunk); 81 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 82 const struct sctp_endpoint *ep, 83 const struct sctp_association *asoc, 84 const sctp_subtype_t type, 85 void *arg, 86 sctp_cmd_seq_t *commands); 87 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 88 const struct sctp_endpoint *ep, 89 const struct sctp_association *asoc, 90 const sctp_subtype_t type, 91 void *arg, 92 sctp_cmd_seq_t *commands); 93 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 94 const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const sctp_subtype_t type, 97 void *arg, 98 sctp_cmd_seq_t *commands); 99 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 100 101 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 102 sctp_cmd_seq_t *commands, 103 __be16 error, int sk_err, 104 const struct sctp_association *asoc, 105 struct sctp_transport *transport); 106 107 static sctp_disposition_t sctp_sf_abort_violation( 108 struct net *net, 109 const struct sctp_endpoint *ep, 110 const struct sctp_association *asoc, 111 void *arg, 112 sctp_cmd_seq_t *commands, 113 const __u8 *payload, 114 const size_t paylen); 115 116 static sctp_disposition_t sctp_sf_violation_chunklen( 117 struct net *net, 118 const struct sctp_endpoint *ep, 119 const struct sctp_association *asoc, 120 const sctp_subtype_t type, 121 void *arg, 122 sctp_cmd_seq_t *commands); 123 124 static sctp_disposition_t sctp_sf_violation_paramlen( 125 struct net *net, 126 const struct sctp_endpoint *ep, 127 const struct sctp_association *asoc, 128 const sctp_subtype_t type, 129 void *arg, void *ext, 130 sctp_cmd_seq_t *commands); 131 132 static sctp_disposition_t sctp_sf_violation_ctsn( 133 struct net *net, 134 const struct sctp_endpoint *ep, 135 const struct sctp_association *asoc, 136 const sctp_subtype_t type, 137 void *arg, 138 sctp_cmd_seq_t *commands); 139 140 static sctp_disposition_t sctp_sf_violation_chunk( 141 struct net *net, 142 const struct sctp_endpoint *ep, 143 const struct sctp_association *asoc, 144 const sctp_subtype_t type, 145 void *arg, 146 sctp_cmd_seq_t *commands); 147 148 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 149 const struct sctp_endpoint *ep, 150 const struct sctp_association *asoc, 151 const sctp_subtype_t type, 152 struct sctp_chunk *chunk); 153 154 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 155 const struct sctp_endpoint *ep, 156 const struct sctp_association *asoc, 157 const sctp_subtype_t type, 158 void *arg, 159 sctp_cmd_seq_t *commands); 160 161 /* Small helper function that checks if the chunk length 162 * is of the appropriate length. The 'required_length' argument 163 * is set to be the size of a specific chunk we are testing. 164 * Return Values: 1 = Valid length 165 * 0 = Invalid length 166 * 167 */ 168 static inline int 169 sctp_chunk_length_valid(struct sctp_chunk *chunk, 170 __u16 required_length) 171 { 172 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 173 174 if (unlikely(chunk_length < required_length)) 175 return 0; 176 177 return 1; 178 } 179 180 /********************************************************** 181 * These are the state functions for handling chunk events. 182 **********************************************************/ 183 184 /* 185 * Process the final SHUTDOWN COMPLETE. 186 * 187 * Section: 4 (C) (diagram), 9.2 188 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 189 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 190 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 191 * should stop the T2-shutdown timer and remove all knowledge of the 192 * association (and thus the association enters the CLOSED state). 193 * 194 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 195 * C) Rules for packet carrying SHUTDOWN COMPLETE: 196 * ... 197 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 198 * if the Verification Tag field of the packet matches its own tag and 199 * the T bit is not set 200 * OR 201 * it is set to its peer's tag and the T bit is set in the Chunk 202 * Flags. 203 * Otherwise, the receiver MUST silently discard the packet 204 * and take no further action. An endpoint MUST ignore the 205 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 206 * 207 * Inputs 208 * (endpoint, asoc, chunk) 209 * 210 * Outputs 211 * (asoc, reply_msg, msg_up, timers, counters) 212 * 213 * The return value is the disposition of the chunk. 214 */ 215 sctp_disposition_t sctp_sf_do_4_C(struct net *net, 216 const struct sctp_endpoint *ep, 217 const struct sctp_association *asoc, 218 const sctp_subtype_t type, 219 void *arg, 220 sctp_cmd_seq_t *commands) 221 { 222 struct sctp_chunk *chunk = arg; 223 struct sctp_ulpevent *ev; 224 225 if (!sctp_vtag_verify_either(chunk, asoc)) 226 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 227 228 /* RFC 2960 6.10 Bundling 229 * 230 * An endpoint MUST NOT bundle INIT, INIT ACK or 231 * SHUTDOWN COMPLETE with any other chunks. 232 */ 233 if (!chunk->singleton) 234 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 235 236 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 237 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 238 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 239 commands); 240 241 /* RFC 2960 10.2 SCTP-to-ULP 242 * 243 * H) SHUTDOWN COMPLETE notification 244 * 245 * When SCTP completes the shutdown procedures (section 9.2) this 246 * notification is passed to the upper layer. 247 */ 248 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 249 0, 0, 0, NULL, GFP_ATOMIC); 250 if (ev) 251 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 252 SCTP_ULPEVENT(ev)); 253 254 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 255 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 256 * not the chunk should be discarded. If the endpoint is in 257 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 258 * T2-shutdown timer and remove all knowledge of the 259 * association (and thus the association enters the CLOSED 260 * state). 261 */ 262 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 263 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 264 265 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 266 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 267 268 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 269 SCTP_STATE(SCTP_STATE_CLOSED)); 270 271 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 272 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 273 274 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 275 276 return SCTP_DISPOSITION_DELETE_TCB; 277 } 278 279 /* 280 * Respond to a normal INIT chunk. 281 * We are the side that is being asked for an association. 282 * 283 * Section: 5.1 Normal Establishment of an Association, B 284 * B) "Z" shall respond immediately with an INIT ACK chunk. The 285 * destination IP address of the INIT ACK MUST be set to the source 286 * IP address of the INIT to which this INIT ACK is responding. In 287 * the response, besides filling in other parameters, "Z" must set the 288 * Verification Tag field to Tag_A, and also provide its own 289 * Verification Tag (Tag_Z) in the Initiate Tag field. 290 * 291 * Verification Tag: Must be 0. 292 * 293 * Inputs 294 * (endpoint, asoc, chunk) 295 * 296 * Outputs 297 * (asoc, reply_msg, msg_up, timers, counters) 298 * 299 * The return value is the disposition of the chunk. 300 */ 301 sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net, 302 const struct sctp_endpoint *ep, 303 const struct sctp_association *asoc, 304 const sctp_subtype_t type, 305 void *arg, 306 sctp_cmd_seq_t *commands) 307 { 308 struct sctp_chunk *chunk = arg; 309 struct sctp_chunk *repl; 310 struct sctp_association *new_asoc; 311 struct sctp_chunk *err_chunk; 312 struct sctp_packet *packet; 313 sctp_unrecognized_param_t *unk_param; 314 int len; 315 316 /* 6.10 Bundling 317 * An endpoint MUST NOT bundle INIT, INIT ACK or 318 * SHUTDOWN COMPLETE with any other chunks. 319 * 320 * IG Section 2.11.2 321 * Furthermore, we require that the receiver of an INIT chunk MUST 322 * enforce these rules by silently discarding an arriving packet 323 * with an INIT chunk that is bundled with other chunks. 324 */ 325 if (!chunk->singleton) 326 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 327 328 /* If the packet is an OOTB packet which is temporarily on the 329 * control endpoint, respond with an ABORT. 330 */ 331 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 332 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 333 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 334 } 335 336 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 337 * Tag. 338 */ 339 if (chunk->sctp_hdr->vtag != 0) 340 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 341 342 /* Make sure that the INIT chunk has a valid length. 343 * Normally, this would cause an ABORT with a Protocol Violation 344 * error, but since we don't have an association, we'll 345 * just discard the packet. 346 */ 347 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 349 350 /* If the INIT is coming toward a closing socket, we'll send back 351 * and ABORT. Essentially, this catches the race of INIT being 352 * backloged to the socket at the same time as the user isses close(). 353 * Since the socket and all its associations are going away, we 354 * can treat this OOTB 355 */ 356 if (sctp_sstate(ep->base.sk, CLOSING)) 357 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 358 359 /* Verify the INIT chunk before processing it. */ 360 err_chunk = NULL; 361 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 362 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 363 &err_chunk)) { 364 /* This chunk contains fatal error. It is to be discarded. 365 * Send an ABORT, with causes if there is any. 366 */ 367 if (err_chunk) { 368 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 369 (__u8 *)(err_chunk->chunk_hdr) + 370 sizeof(sctp_chunkhdr_t), 371 ntohs(err_chunk->chunk_hdr->length) - 372 sizeof(sctp_chunkhdr_t)); 373 374 sctp_chunk_free(err_chunk); 375 376 if (packet) { 377 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 378 SCTP_PACKET(packet)); 379 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 380 return SCTP_DISPOSITION_CONSUME; 381 } else { 382 return SCTP_DISPOSITION_NOMEM; 383 } 384 } else { 385 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 386 commands); 387 } 388 } 389 390 /* Grab the INIT header. */ 391 chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; 392 393 /* Tag the variable length parameters. */ 394 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 395 396 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 397 if (!new_asoc) 398 goto nomem; 399 400 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 401 sctp_scope(sctp_source(chunk)), 402 GFP_ATOMIC) < 0) 403 goto nomem_init; 404 405 /* The call, sctp_process_init(), can fail on memory allocation. */ 406 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 407 (sctp_init_chunk_t *)chunk->chunk_hdr, 408 GFP_ATOMIC)) 409 goto nomem_init; 410 411 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 412 413 /* If there are errors need to be reported for unknown parameters, 414 * make sure to reserve enough room in the INIT ACK for them. 415 */ 416 len = 0; 417 if (err_chunk) 418 len = ntohs(err_chunk->chunk_hdr->length) - 419 sizeof(sctp_chunkhdr_t); 420 421 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 422 if (!repl) 423 goto nomem_init; 424 425 /* If there are errors need to be reported for unknown parameters, 426 * include them in the outgoing INIT ACK as "Unrecognized parameter" 427 * parameter. 428 */ 429 if (err_chunk) { 430 /* Get the "Unrecognized parameter" parameter(s) out of the 431 * ERROR chunk generated by sctp_verify_init(). Since the 432 * error cause code for "unknown parameter" and the 433 * "Unrecognized parameter" type is the same, we can 434 * construct the parameters in INIT ACK by copying the 435 * ERROR causes over. 436 */ 437 unk_param = (sctp_unrecognized_param_t *) 438 ((__u8 *)(err_chunk->chunk_hdr) + 439 sizeof(sctp_chunkhdr_t)); 440 /* Replace the cause code with the "Unrecognized parameter" 441 * parameter type. 442 */ 443 sctp_addto_chunk(repl, len, unk_param); 444 sctp_chunk_free(err_chunk); 445 } 446 447 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 448 449 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 450 451 /* 452 * Note: After sending out INIT ACK with the State Cookie parameter, 453 * "Z" MUST NOT allocate any resources, nor keep any states for the 454 * new association. Otherwise, "Z" will be vulnerable to resource 455 * attacks. 456 */ 457 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 458 459 return SCTP_DISPOSITION_DELETE_TCB; 460 461 nomem_init: 462 sctp_association_free(new_asoc); 463 nomem: 464 if (err_chunk) 465 sctp_chunk_free(err_chunk); 466 return SCTP_DISPOSITION_NOMEM; 467 } 468 469 /* 470 * Respond to a normal INIT ACK chunk. 471 * We are the side that is initiating the association. 472 * 473 * Section: 5.1 Normal Establishment of an Association, C 474 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 475 * timer and leave COOKIE-WAIT state. "A" shall then send the State 476 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 477 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 478 * 479 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 480 * DATA chunks, but it MUST be the first chunk in the packet and 481 * until the COOKIE ACK is returned the sender MUST NOT send any 482 * other packets to the peer. 483 * 484 * Verification Tag: 3.3.3 485 * If the value of the Initiate Tag in a received INIT ACK chunk is 486 * found to be 0, the receiver MUST treat it as an error and close the 487 * association by transmitting an ABORT. 488 * 489 * Inputs 490 * (endpoint, asoc, chunk) 491 * 492 * Outputs 493 * (asoc, reply_msg, msg_up, timers, counters) 494 * 495 * The return value is the disposition of the chunk. 496 */ 497 sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net, 498 const struct sctp_endpoint *ep, 499 const struct sctp_association *asoc, 500 const sctp_subtype_t type, 501 void *arg, 502 sctp_cmd_seq_t *commands) 503 { 504 struct sctp_chunk *chunk = arg; 505 sctp_init_chunk_t *initchunk; 506 struct sctp_chunk *err_chunk; 507 struct sctp_packet *packet; 508 509 if (!sctp_vtag_verify(chunk, asoc)) 510 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 511 512 /* 6.10 Bundling 513 * An endpoint MUST NOT bundle INIT, INIT ACK or 514 * SHUTDOWN COMPLETE with any other chunks. 515 */ 516 if (!chunk->singleton) 517 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 518 519 /* Make sure that the INIT-ACK chunk has a valid length */ 520 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t))) 521 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 522 commands); 523 /* Grab the INIT header. */ 524 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 525 526 /* Verify the INIT chunk before processing it. */ 527 err_chunk = NULL; 528 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 529 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 530 &err_chunk)) { 531 532 sctp_error_t error = SCTP_ERROR_NO_RESOURCE; 533 534 /* This chunk contains fatal error. It is to be discarded. 535 * Send an ABORT, with causes. If there are no causes, 536 * then there wasn't enough memory. Just terminate 537 * the association. 538 */ 539 if (err_chunk) { 540 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 541 (__u8 *)(err_chunk->chunk_hdr) + 542 sizeof(sctp_chunkhdr_t), 543 ntohs(err_chunk->chunk_hdr->length) - 544 sizeof(sctp_chunkhdr_t)); 545 546 sctp_chunk_free(err_chunk); 547 548 if (packet) { 549 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 550 SCTP_PACKET(packet)); 551 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 552 error = SCTP_ERROR_INV_PARAM; 553 } 554 } 555 556 /* SCTP-AUTH, Section 6.3: 557 * It should be noted that if the receiver wants to tear 558 * down an association in an authenticated way only, the 559 * handling of malformed packets should not result in 560 * tearing down the association. 561 * 562 * This means that if we only want to abort associations 563 * in an authenticated way (i.e AUTH+ABORT), then we 564 * can't destroy this association just because the packet 565 * was malformed. 566 */ 567 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 568 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 569 570 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 571 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 572 asoc, chunk->transport); 573 } 574 575 /* Tag the variable length parameters. Note that we never 576 * convert the parameters in an INIT chunk. 577 */ 578 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 579 580 initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; 581 582 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 583 SCTP_PEER_INIT(initchunk)); 584 585 /* Reset init error count upon receipt of INIT-ACK. */ 586 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 587 588 /* 5.1 C) "A" shall stop the T1-init timer and leave 589 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 590 * timer, and enter the COOKIE-ECHOED state. 591 */ 592 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 593 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 594 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 595 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 596 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 597 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 598 599 /* SCTP-AUTH: genereate the assocition shared keys so that 600 * we can potentially signe the COOKIE-ECHO. 601 */ 602 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 603 604 /* 5.1 C) "A" shall then send the State Cookie received in the 605 * INIT ACK chunk in a COOKIE ECHO chunk, ... 606 */ 607 /* If there is any errors to report, send the ERROR chunk generated 608 * for unknown parameters as well. 609 */ 610 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 611 SCTP_CHUNK(err_chunk)); 612 613 return SCTP_DISPOSITION_CONSUME; 614 } 615 616 /* 617 * Respond to a normal COOKIE ECHO chunk. 618 * We are the side that is being asked for an association. 619 * 620 * Section: 5.1 Normal Establishment of an Association, D 621 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 622 * with a COOKIE ACK chunk after building a TCB and moving to 623 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 624 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 625 * chunk MUST be the first chunk in the packet. 626 * 627 * IMPLEMENTATION NOTE: An implementation may choose to send the 628 * Communication Up notification to the SCTP user upon reception 629 * of a valid COOKIE ECHO chunk. 630 * 631 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 632 * D) Rules for packet carrying a COOKIE ECHO 633 * 634 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 635 * Initial Tag received in the INIT ACK. 636 * 637 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 638 * 639 * Inputs 640 * (endpoint, asoc, chunk) 641 * 642 * Outputs 643 * (asoc, reply_msg, msg_up, timers, counters) 644 * 645 * The return value is the disposition of the chunk. 646 */ 647 sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net, 648 const struct sctp_endpoint *ep, 649 const struct sctp_association *asoc, 650 const sctp_subtype_t type, void *arg, 651 sctp_cmd_seq_t *commands) 652 { 653 struct sctp_chunk *chunk = arg; 654 struct sctp_association *new_asoc; 655 sctp_init_chunk_t *peer_init; 656 struct sctp_chunk *repl; 657 struct sctp_ulpevent *ev, *ai_ev = NULL; 658 int error = 0; 659 struct sctp_chunk *err_chk_p; 660 struct sock *sk; 661 662 /* If the packet is an OOTB packet which is temporarily on the 663 * control endpoint, respond with an ABORT. 664 */ 665 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 666 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 667 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 668 } 669 670 /* Make sure that the COOKIE_ECHO chunk has a valid length. 671 * In this case, we check that we have enough for at least a 672 * chunk header. More detailed verification is done 673 * in sctp_unpack_cookie(). 674 */ 675 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 676 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 677 678 /* If the endpoint is not listening or if the number of associations 679 * on the TCP-style socket exceed the max backlog, respond with an 680 * ABORT. 681 */ 682 sk = ep->base.sk; 683 if (!sctp_sstate(sk, LISTENING) || 684 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 685 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 686 687 /* "Decode" the chunk. We have no optional parameters so we 688 * are in good shape. 689 */ 690 chunk->subh.cookie_hdr = 691 (struct sctp_signed_cookie *)chunk->skb->data; 692 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 693 sizeof(sctp_chunkhdr_t))) 694 goto nomem; 695 696 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 697 * "Z" will reply with a COOKIE ACK chunk after building a TCB 698 * and moving to the ESTABLISHED state. 699 */ 700 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 701 &err_chk_p); 702 703 /* FIXME: 704 * If the re-build failed, what is the proper error path 705 * from here? 706 * 707 * [We should abort the association. --piggy] 708 */ 709 if (!new_asoc) { 710 /* FIXME: Several errors are possible. A bad cookie should 711 * be silently discarded, but think about logging it too. 712 */ 713 switch (error) { 714 case -SCTP_IERROR_NOMEM: 715 goto nomem; 716 717 case -SCTP_IERROR_STALE_COOKIE: 718 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 719 err_chk_p); 720 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 721 722 case -SCTP_IERROR_BAD_SIG: 723 default: 724 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 725 } 726 } 727 728 729 /* Delay state machine commands until later. 730 * 731 * Re-build the bind address for the association is done in 732 * the sctp_unpack_cookie() already. 733 */ 734 /* This is a brand-new association, so these are not yet side 735 * effects--it is safe to run them here. 736 */ 737 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 738 739 if (!sctp_process_init(new_asoc, chunk, 740 &chunk->subh.cookie_hdr->c.peer_addr, 741 peer_init, GFP_ATOMIC)) 742 goto nomem_init; 743 744 /* SCTP-AUTH: Now that we've populate required fields in 745 * sctp_process_init, set up the assocaition shared keys as 746 * necessary so that we can potentially authenticate the ACK 747 */ 748 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 749 if (error) 750 goto nomem_init; 751 752 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 753 * is supposed to be authenticated and we have to do delayed 754 * authentication. We've just recreated the association using 755 * the information in the cookie and now it's much easier to 756 * do the authentication. 757 */ 758 if (chunk->auth_chunk) { 759 struct sctp_chunk auth; 760 sctp_ierror_t ret; 761 762 /* set-up our fake chunk so that we can process it */ 763 auth.skb = chunk->auth_chunk; 764 auth.asoc = chunk->asoc; 765 auth.sctp_hdr = chunk->sctp_hdr; 766 auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk, 767 sizeof(sctp_chunkhdr_t)); 768 skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t)); 769 auth.transport = chunk->transport; 770 771 ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth); 772 773 /* We can now safely free the auth_chunk clone */ 774 kfree_skb(chunk->auth_chunk); 775 776 if (ret != SCTP_IERROR_NO_ERROR) { 777 sctp_association_free(new_asoc); 778 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 779 } 780 } 781 782 repl = sctp_make_cookie_ack(new_asoc, chunk); 783 if (!repl) 784 goto nomem_init; 785 786 /* RFC 2960 5.1 Normal Establishment of an Association 787 * 788 * D) IMPLEMENTATION NOTE: An implementation may choose to 789 * send the Communication Up notification to the SCTP user 790 * upon reception of a valid COOKIE ECHO chunk. 791 */ 792 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 793 new_asoc->c.sinit_num_ostreams, 794 new_asoc->c.sinit_max_instreams, 795 NULL, GFP_ATOMIC); 796 if (!ev) 797 goto nomem_ev; 798 799 /* Sockets API Draft Section 5.3.1.6 800 * When a peer sends a Adaptation Layer Indication parameter , SCTP 801 * delivers this notification to inform the application that of the 802 * peers requested adaptation layer. 803 */ 804 if (new_asoc->peer.adaptation_ind) { 805 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 806 GFP_ATOMIC); 807 if (!ai_ev) 808 goto nomem_aiev; 809 } 810 811 /* Add all the state machine commands now since we've created 812 * everything. This way we don't introduce memory corruptions 813 * during side-effect processing and correclty count established 814 * associations. 815 */ 816 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 817 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 818 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 819 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 820 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 821 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 822 823 if (new_asoc->autoclose) 824 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 825 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 826 827 /* This will send the COOKIE ACK */ 828 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 829 830 /* Queue the ASSOC_CHANGE event */ 831 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 832 833 /* Send up the Adaptation Layer Indication event */ 834 if (ai_ev) 835 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 836 SCTP_ULPEVENT(ai_ev)); 837 838 return SCTP_DISPOSITION_CONSUME; 839 840 nomem_aiev: 841 sctp_ulpevent_free(ev); 842 nomem_ev: 843 sctp_chunk_free(repl); 844 nomem_init: 845 sctp_association_free(new_asoc); 846 nomem: 847 return SCTP_DISPOSITION_NOMEM; 848 } 849 850 /* 851 * Respond to a normal COOKIE ACK chunk. 852 * We are the side that is being asked for an association. 853 * 854 * RFC 2960 5.1 Normal Establishment of an Association 855 * 856 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 857 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 858 * timer. It may also notify its ULP about the successful 859 * establishment of the association with a Communication Up 860 * notification (see Section 10). 861 * 862 * Verification Tag: 863 * Inputs 864 * (endpoint, asoc, chunk) 865 * 866 * Outputs 867 * (asoc, reply_msg, msg_up, timers, counters) 868 * 869 * The return value is the disposition of the chunk. 870 */ 871 sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net, 872 const struct sctp_endpoint *ep, 873 const struct sctp_association *asoc, 874 const sctp_subtype_t type, void *arg, 875 sctp_cmd_seq_t *commands) 876 { 877 struct sctp_chunk *chunk = arg; 878 struct sctp_ulpevent *ev; 879 880 if (!sctp_vtag_verify(chunk, asoc)) 881 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 882 883 /* Verify that the chunk length for the COOKIE-ACK is OK. 884 * If we don't do this, any bundled chunks may be junked. 885 */ 886 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 887 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 888 commands); 889 890 /* Reset init error count upon receipt of COOKIE-ACK, 891 * to avoid problems with the managemement of this 892 * counter in stale cookie situations when a transition back 893 * from the COOKIE-ECHOED state to the COOKIE-WAIT 894 * state is performed. 895 */ 896 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 897 898 /* RFC 2960 5.1 Normal Establishment of an Association 899 * 900 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 901 * from the COOKIE-ECHOED state to the ESTABLISHED state, 902 * stopping the T1-cookie timer. 903 */ 904 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 905 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 906 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 907 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 908 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 909 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 910 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 911 if (asoc->autoclose) 912 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 913 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 914 915 /* It may also notify its ULP about the successful 916 * establishment of the association with a Communication Up 917 * notification (see Section 10). 918 */ 919 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 920 0, asoc->c.sinit_num_ostreams, 921 asoc->c.sinit_max_instreams, 922 NULL, GFP_ATOMIC); 923 924 if (!ev) 925 goto nomem; 926 927 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 928 929 /* Sockets API Draft Section 5.3.1.6 930 * When a peer sends a Adaptation Layer Indication parameter , SCTP 931 * delivers this notification to inform the application that of the 932 * peers requested adaptation layer. 933 */ 934 if (asoc->peer.adaptation_ind) { 935 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 936 if (!ev) 937 goto nomem; 938 939 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 940 SCTP_ULPEVENT(ev)); 941 } 942 943 return SCTP_DISPOSITION_CONSUME; 944 nomem: 945 return SCTP_DISPOSITION_NOMEM; 946 } 947 948 /* Generate and sendout a heartbeat packet. */ 949 static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, 950 const struct sctp_association *asoc, 951 const sctp_subtype_t type, 952 void *arg, 953 sctp_cmd_seq_t *commands) 954 { 955 struct sctp_transport *transport = (struct sctp_transport *) arg; 956 struct sctp_chunk *reply; 957 958 /* Send a heartbeat to our peer. */ 959 reply = sctp_make_heartbeat(asoc, transport); 960 if (!reply) 961 return SCTP_DISPOSITION_NOMEM; 962 963 /* Set rto_pending indicating that an RTT measurement 964 * is started with this heartbeat chunk. 965 */ 966 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 967 SCTP_TRANSPORT(transport)); 968 969 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 970 return SCTP_DISPOSITION_CONSUME; 971 } 972 973 /* Generate a HEARTBEAT packet on the given transport. */ 974 sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net, 975 const struct sctp_endpoint *ep, 976 const struct sctp_association *asoc, 977 const sctp_subtype_t type, 978 void *arg, 979 sctp_cmd_seq_t *commands) 980 { 981 struct sctp_transport *transport = (struct sctp_transport *) arg; 982 983 if (asoc->overall_error_count >= asoc->max_retrans) { 984 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 985 SCTP_ERROR(ETIMEDOUT)); 986 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 987 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 988 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 989 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 990 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 991 return SCTP_DISPOSITION_DELETE_TCB; 992 } 993 994 /* Section 3.3.5. 995 * The Sender-specific Heartbeat Info field should normally include 996 * information about the sender's current time when this HEARTBEAT 997 * chunk is sent and the destination transport address to which this 998 * HEARTBEAT is sent (see Section 8.3). 999 */ 1000 1001 if (transport->param_flags & SPP_HB_ENABLE) { 1002 if (SCTP_DISPOSITION_NOMEM == 1003 sctp_sf_heartbeat(ep, asoc, type, arg, 1004 commands)) 1005 return SCTP_DISPOSITION_NOMEM; 1006 1007 /* Set transport error counter and association error counter 1008 * when sending heartbeat. 1009 */ 1010 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1011 SCTP_TRANSPORT(transport)); 1012 } 1013 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1014 SCTP_TRANSPORT(transport)); 1015 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1016 SCTP_TRANSPORT(transport)); 1017 1018 return SCTP_DISPOSITION_CONSUME; 1019 } 1020 1021 /* 1022 * Process an heartbeat request. 1023 * 1024 * Section: 8.3 Path Heartbeat 1025 * The receiver of the HEARTBEAT should immediately respond with a 1026 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1027 * from the received HEARTBEAT chunk. 1028 * 1029 * Verification Tag: 8.5 Verification Tag [Normal verification] 1030 * When receiving an SCTP packet, the endpoint MUST ensure that the 1031 * value in the Verification Tag field of the received SCTP packet 1032 * matches its own Tag. If the received Verification Tag value does not 1033 * match the receiver's own tag value, the receiver shall silently 1034 * discard the packet and shall not process it any further except for 1035 * those cases listed in Section 8.5.1 below. 1036 * 1037 * Inputs 1038 * (endpoint, asoc, chunk) 1039 * 1040 * Outputs 1041 * (asoc, reply_msg, msg_up, timers, counters) 1042 * 1043 * The return value is the disposition of the chunk. 1044 */ 1045 sctp_disposition_t sctp_sf_beat_8_3(struct net *net, 1046 const struct sctp_endpoint *ep, 1047 const struct sctp_association *asoc, 1048 const sctp_subtype_t type, 1049 void *arg, 1050 sctp_cmd_seq_t *commands) 1051 { 1052 sctp_paramhdr_t *param_hdr; 1053 struct sctp_chunk *chunk = arg; 1054 struct sctp_chunk *reply; 1055 size_t paylen = 0; 1056 1057 if (!sctp_vtag_verify(chunk, asoc)) 1058 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1059 1060 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1061 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t))) 1062 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1063 commands); 1064 1065 /* 8.3 The receiver of the HEARTBEAT should immediately 1066 * respond with a HEARTBEAT ACK that contains the Heartbeat 1067 * Information field copied from the received HEARTBEAT chunk. 1068 */ 1069 chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; 1070 param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr; 1071 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); 1072 1073 if (ntohs(param_hdr->length) > paylen) 1074 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1075 param_hdr, commands); 1076 1077 if (!pskb_pull(chunk->skb, paylen)) 1078 goto nomem; 1079 1080 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1081 if (!reply) 1082 goto nomem; 1083 1084 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1085 return SCTP_DISPOSITION_CONSUME; 1086 1087 nomem: 1088 return SCTP_DISPOSITION_NOMEM; 1089 } 1090 1091 /* 1092 * Process the returning HEARTBEAT ACK. 1093 * 1094 * Section: 8.3 Path Heartbeat 1095 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1096 * should clear the error counter of the destination transport 1097 * address to which the HEARTBEAT was sent, and mark the destination 1098 * transport address as active if it is not so marked. The endpoint may 1099 * optionally report to the upper layer when an inactive destination 1100 * address is marked as active due to the reception of the latest 1101 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1102 * clear the association overall error count as well (as defined 1103 * in section 8.1). 1104 * 1105 * The receiver of the HEARTBEAT ACK should also perform an RTT 1106 * measurement for that destination transport address using the time 1107 * value carried in the HEARTBEAT ACK chunk. 1108 * 1109 * Verification Tag: 8.5 Verification Tag [Normal verification] 1110 * 1111 * Inputs 1112 * (endpoint, asoc, chunk) 1113 * 1114 * Outputs 1115 * (asoc, reply_msg, msg_up, timers, counters) 1116 * 1117 * The return value is the disposition of the chunk. 1118 */ 1119 sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net, 1120 const struct sctp_endpoint *ep, 1121 const struct sctp_association *asoc, 1122 const sctp_subtype_t type, 1123 void *arg, 1124 sctp_cmd_seq_t *commands) 1125 { 1126 struct sctp_chunk *chunk = arg; 1127 union sctp_addr from_addr; 1128 struct sctp_transport *link; 1129 sctp_sender_hb_info_t *hbinfo; 1130 unsigned long max_interval; 1131 1132 if (!sctp_vtag_verify(chunk, asoc)) 1133 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1134 1135 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1136 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) + 1137 sizeof(sctp_sender_hb_info_t))) 1138 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1139 commands); 1140 1141 hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; 1142 /* Make sure that the length of the parameter is what we expect */ 1143 if (ntohs(hbinfo->param_hdr.length) != 1144 sizeof(sctp_sender_hb_info_t)) { 1145 return SCTP_DISPOSITION_DISCARD; 1146 } 1147 1148 from_addr = hbinfo->daddr; 1149 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1150 1151 /* This should never happen, but lets log it if so. */ 1152 if (unlikely(!link)) { 1153 if (from_addr.sa.sa_family == AF_INET6) { 1154 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1155 __func__, 1156 asoc, 1157 &from_addr.v6.sin6_addr); 1158 } else { 1159 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1160 __func__, 1161 asoc, 1162 &from_addr.v4.sin_addr.s_addr); 1163 } 1164 return SCTP_DISPOSITION_DISCARD; 1165 } 1166 1167 /* Validate the 64-bit random nonce. */ 1168 if (hbinfo->hb_nonce != link->hb_nonce) 1169 return SCTP_DISPOSITION_DISCARD; 1170 1171 max_interval = link->hbinterval + link->rto; 1172 1173 /* Check if the timestamp looks valid. */ 1174 if (time_after(hbinfo->sent_at, jiffies) || 1175 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1176 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1177 "for transport:%p\n", __func__, link); 1178 1179 return SCTP_DISPOSITION_DISCARD; 1180 } 1181 1182 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1183 * the HEARTBEAT should clear the error counter of the 1184 * destination transport address to which the HEARTBEAT was 1185 * sent and mark the destination transport address as active if 1186 * it is not so marked. 1187 */ 1188 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1189 1190 return SCTP_DISPOSITION_CONSUME; 1191 } 1192 1193 /* Helper function to send out an abort for the restart 1194 * condition. 1195 */ 1196 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1197 struct sctp_chunk *init, 1198 sctp_cmd_seq_t *commands) 1199 { 1200 int len; 1201 struct sctp_packet *pkt; 1202 union sctp_addr_param *addrparm; 1203 struct sctp_errhdr *errhdr; 1204 struct sctp_endpoint *ep; 1205 char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; 1206 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1207 1208 /* Build the error on the stack. We are way to malloc crazy 1209 * throughout the code today. 1210 */ 1211 errhdr = (struct sctp_errhdr *)buffer; 1212 addrparm = (union sctp_addr_param *)errhdr->variable; 1213 1214 /* Copy into a parm format. */ 1215 len = af->to_addr_param(ssa, addrparm); 1216 len += sizeof(sctp_errhdr_t); 1217 1218 errhdr->cause = SCTP_ERROR_RESTART; 1219 errhdr->length = htons(len); 1220 1221 /* Assign to the control socket. */ 1222 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1223 1224 /* Association is NULL since this may be a restart attack and we 1225 * want to send back the attacker's vtag. 1226 */ 1227 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1228 1229 if (!pkt) 1230 goto out; 1231 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1232 1233 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1234 1235 /* Discard the rest of the inbound packet. */ 1236 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1237 1238 out: 1239 /* Even if there is no memory, treat as a failure so 1240 * the packet will get dropped. 1241 */ 1242 return 0; 1243 } 1244 1245 static bool list_has_sctp_addr(const struct list_head *list, 1246 union sctp_addr *ipaddr) 1247 { 1248 struct sctp_transport *addr; 1249 1250 list_for_each_entry(addr, list, transports) { 1251 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1252 return true; 1253 } 1254 1255 return false; 1256 } 1257 /* A restart is occurring, check to make sure no new addresses 1258 * are being added as we may be under a takeover attack. 1259 */ 1260 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1261 const struct sctp_association *asoc, 1262 struct sctp_chunk *init, 1263 sctp_cmd_seq_t *commands) 1264 { 1265 struct net *net = sock_net(new_asoc->base.sk); 1266 struct sctp_transport *new_addr; 1267 int ret = 1; 1268 1269 /* Implementor's Guide - Section 5.2.2 1270 * ... 1271 * Before responding the endpoint MUST check to see if the 1272 * unexpected INIT adds new addresses to the association. If new 1273 * addresses are added to the association, the endpoint MUST respond 1274 * with an ABORT.. 1275 */ 1276 1277 /* Search through all current addresses and make sure 1278 * we aren't adding any new ones. 1279 */ 1280 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1281 transports) { 1282 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1283 &new_addr->ipaddr)) { 1284 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1285 commands); 1286 ret = 0; 1287 break; 1288 } 1289 } 1290 1291 /* Return success if all addresses were found. */ 1292 return ret; 1293 } 1294 1295 /* Populate the verification/tie tags based on overlapping INIT 1296 * scenario. 1297 * 1298 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1299 */ 1300 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1301 const struct sctp_association *asoc) 1302 { 1303 switch (asoc->state) { 1304 1305 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1306 1307 case SCTP_STATE_COOKIE_WAIT: 1308 new_asoc->c.my_vtag = asoc->c.my_vtag; 1309 new_asoc->c.my_ttag = asoc->c.my_vtag; 1310 new_asoc->c.peer_ttag = 0; 1311 break; 1312 1313 case SCTP_STATE_COOKIE_ECHOED: 1314 new_asoc->c.my_vtag = asoc->c.my_vtag; 1315 new_asoc->c.my_ttag = asoc->c.my_vtag; 1316 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1317 break; 1318 1319 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1320 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1321 */ 1322 default: 1323 new_asoc->c.my_ttag = asoc->c.my_vtag; 1324 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1325 break; 1326 } 1327 1328 /* Other parameters for the endpoint SHOULD be copied from the 1329 * existing parameters of the association (e.g. number of 1330 * outbound streams) into the INIT ACK and cookie. 1331 */ 1332 new_asoc->rwnd = asoc->rwnd; 1333 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1334 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1335 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1336 } 1337 1338 /* 1339 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1340 * handling action. 1341 * 1342 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1343 * 1344 * Returns value representing action to be taken. These action values 1345 * correspond to Action/Description values in RFC 2960, Table 2. 1346 */ 1347 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1348 const struct sctp_association *asoc) 1349 { 1350 /* In this case, the peer may have restarted. */ 1351 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1352 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1353 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1354 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1355 return 'A'; 1356 1357 /* Collision case B. */ 1358 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1359 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1360 (0 == asoc->c.peer_vtag))) { 1361 return 'B'; 1362 } 1363 1364 /* Collision case D. */ 1365 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1366 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1367 return 'D'; 1368 1369 /* Collision case C. */ 1370 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1371 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1372 (0 == new_asoc->c.my_ttag) && 1373 (0 == new_asoc->c.peer_ttag)) 1374 return 'C'; 1375 1376 /* No match to any of the special cases; discard this packet. */ 1377 return 'E'; 1378 } 1379 1380 /* Common helper routine for both duplicate and simulataneous INIT 1381 * chunk handling. 1382 */ 1383 static sctp_disposition_t sctp_sf_do_unexpected_init( 1384 struct net *net, 1385 const struct sctp_endpoint *ep, 1386 const struct sctp_association *asoc, 1387 const sctp_subtype_t type, 1388 void *arg, sctp_cmd_seq_t *commands) 1389 { 1390 sctp_disposition_t retval; 1391 struct sctp_chunk *chunk = arg; 1392 struct sctp_chunk *repl; 1393 struct sctp_association *new_asoc; 1394 struct sctp_chunk *err_chunk; 1395 struct sctp_packet *packet; 1396 sctp_unrecognized_param_t *unk_param; 1397 int len; 1398 1399 /* 6.10 Bundling 1400 * An endpoint MUST NOT bundle INIT, INIT ACK or 1401 * SHUTDOWN COMPLETE with any other chunks. 1402 * 1403 * IG Section 2.11.2 1404 * Furthermore, we require that the receiver of an INIT chunk MUST 1405 * enforce these rules by silently discarding an arriving packet 1406 * with an INIT chunk that is bundled with other chunks. 1407 */ 1408 if (!chunk->singleton) 1409 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1410 1411 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1412 * Tag. 1413 */ 1414 if (chunk->sctp_hdr->vtag != 0) 1415 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1416 1417 /* Make sure that the INIT chunk has a valid length. 1418 * In this case, we generate a protocol violation since we have 1419 * an association established. 1420 */ 1421 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t))) 1422 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1423 commands); 1424 /* Grab the INIT header. */ 1425 chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; 1426 1427 /* Tag the variable length parameters. */ 1428 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); 1429 1430 /* Verify the INIT chunk before processing it. */ 1431 err_chunk = NULL; 1432 if (!sctp_verify_init(net, asoc, chunk->chunk_hdr->type, 1433 (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, 1434 &err_chunk)) { 1435 /* This chunk contains fatal error. It is to be discarded. 1436 * Send an ABORT, with causes if there is any. 1437 */ 1438 if (err_chunk) { 1439 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1440 (__u8 *)(err_chunk->chunk_hdr) + 1441 sizeof(sctp_chunkhdr_t), 1442 ntohs(err_chunk->chunk_hdr->length) - 1443 sizeof(sctp_chunkhdr_t)); 1444 1445 if (packet) { 1446 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1447 SCTP_PACKET(packet)); 1448 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1449 retval = SCTP_DISPOSITION_CONSUME; 1450 } else { 1451 retval = SCTP_DISPOSITION_NOMEM; 1452 } 1453 goto cleanup; 1454 } else { 1455 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1456 commands); 1457 } 1458 } 1459 1460 /* 1461 * Other parameters for the endpoint SHOULD be copied from the 1462 * existing parameters of the association (e.g. number of 1463 * outbound streams) into the INIT ACK and cookie. 1464 * FIXME: We are copying parameters from the endpoint not the 1465 * association. 1466 */ 1467 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1468 if (!new_asoc) 1469 goto nomem; 1470 1471 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1472 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1473 goto nomem; 1474 1475 /* In the outbound INIT ACK the endpoint MUST copy its current 1476 * Verification Tag and Peers Verification tag into a reserved 1477 * place (local tie-tag and per tie-tag) within the state cookie. 1478 */ 1479 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1480 (sctp_init_chunk_t *)chunk->chunk_hdr, 1481 GFP_ATOMIC)) 1482 goto nomem; 1483 1484 /* Make sure no new addresses are being added during the 1485 * restart. Do not do this check for COOKIE-WAIT state, 1486 * since there are no peer addresses to check against. 1487 * Upon return an ABORT will have been sent if needed. 1488 */ 1489 if (!sctp_state(asoc, COOKIE_WAIT)) { 1490 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1491 commands)) { 1492 retval = SCTP_DISPOSITION_CONSUME; 1493 goto nomem_retval; 1494 } 1495 } 1496 1497 sctp_tietags_populate(new_asoc, asoc); 1498 1499 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1500 1501 /* If there are errors need to be reported for unknown parameters, 1502 * make sure to reserve enough room in the INIT ACK for them. 1503 */ 1504 len = 0; 1505 if (err_chunk) { 1506 len = ntohs(err_chunk->chunk_hdr->length) - 1507 sizeof(sctp_chunkhdr_t); 1508 } 1509 1510 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1511 if (!repl) 1512 goto nomem; 1513 1514 /* If there are errors need to be reported for unknown parameters, 1515 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1516 * parameter. 1517 */ 1518 if (err_chunk) { 1519 /* Get the "Unrecognized parameter" parameter(s) out of the 1520 * ERROR chunk generated by sctp_verify_init(). Since the 1521 * error cause code for "unknown parameter" and the 1522 * "Unrecognized parameter" type is the same, we can 1523 * construct the parameters in INIT ACK by copying the 1524 * ERROR causes over. 1525 */ 1526 unk_param = (sctp_unrecognized_param_t *) 1527 ((__u8 *)(err_chunk->chunk_hdr) + 1528 sizeof(sctp_chunkhdr_t)); 1529 /* Replace the cause code with the "Unrecognized parameter" 1530 * parameter type. 1531 */ 1532 sctp_addto_chunk(repl, len, unk_param); 1533 } 1534 1535 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1536 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1537 1538 /* 1539 * Note: After sending out INIT ACK with the State Cookie parameter, 1540 * "Z" MUST NOT allocate any resources for this new association. 1541 * Otherwise, "Z" will be vulnerable to resource attacks. 1542 */ 1543 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1544 retval = SCTP_DISPOSITION_CONSUME; 1545 1546 return retval; 1547 1548 nomem: 1549 retval = SCTP_DISPOSITION_NOMEM; 1550 nomem_retval: 1551 if (new_asoc) 1552 sctp_association_free(new_asoc); 1553 cleanup: 1554 if (err_chunk) 1555 sctp_chunk_free(err_chunk); 1556 return retval; 1557 } 1558 1559 /* 1560 * Handle simultaneous INIT. 1561 * This means we started an INIT and then we got an INIT request from 1562 * our peer. 1563 * 1564 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1565 * This usually indicates an initialization collision, i.e., each 1566 * endpoint is attempting, at about the same time, to establish an 1567 * association with the other endpoint. 1568 * 1569 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1570 * endpoint MUST respond with an INIT ACK using the same parameters it 1571 * sent in its original INIT chunk (including its Verification Tag, 1572 * unchanged). These original parameters are combined with those from the 1573 * newly received INIT chunk. The endpoint shall also generate a State 1574 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1575 * INIT to calculate the State Cookie. 1576 * 1577 * After that, the endpoint MUST NOT change its state, the T1-init 1578 * timer shall be left running and the corresponding TCB MUST NOT be 1579 * destroyed. The normal procedures for handling State Cookies when 1580 * a TCB exists will resolve the duplicate INITs to a single association. 1581 * 1582 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1583 * its Tie-Tags with the Tag information of itself and its peer (see 1584 * section 5.2.2 for a description of the Tie-Tags). 1585 * 1586 * Verification Tag: Not explicit, but an INIT can not have a valid 1587 * verification tag, so we skip the check. 1588 * 1589 * Inputs 1590 * (endpoint, asoc, chunk) 1591 * 1592 * Outputs 1593 * (asoc, reply_msg, msg_up, timers, counters) 1594 * 1595 * The return value is the disposition of the chunk. 1596 */ 1597 sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net, 1598 const struct sctp_endpoint *ep, 1599 const struct sctp_association *asoc, 1600 const sctp_subtype_t type, 1601 void *arg, 1602 sctp_cmd_seq_t *commands) 1603 { 1604 /* Call helper to do the real work for both simulataneous and 1605 * duplicate INIT chunk handling. 1606 */ 1607 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1608 } 1609 1610 /* 1611 * Handle duplicated INIT messages. These are usually delayed 1612 * restransmissions. 1613 * 1614 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1615 * COOKIE-ECHOED and COOKIE-WAIT 1616 * 1617 * Unless otherwise stated, upon reception of an unexpected INIT for 1618 * this association, the endpoint shall generate an INIT ACK with a 1619 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1620 * current Verification Tag and peer's Verification Tag into a reserved 1621 * place within the state cookie. We shall refer to these locations as 1622 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1623 * containing this INIT ACK MUST carry a Verification Tag value equal to 1624 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1625 * MUST contain a new Initiation Tag (randomly generated see Section 1626 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1627 * existing parameters of the association (e.g. number of outbound 1628 * streams) into the INIT ACK and cookie. 1629 * 1630 * After sending out the INIT ACK, the endpoint shall take no further 1631 * actions, i.e., the existing association, including its current state, 1632 * and the corresponding TCB MUST NOT be changed. 1633 * 1634 * Note: Only when a TCB exists and the association is not in a COOKIE- 1635 * WAIT state are the Tie-Tags populated. For a normal association INIT 1636 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1637 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1638 * State Cookie are populated as specified in section 5.2.1. 1639 * 1640 * Verification Tag: Not specified, but an INIT has no way of knowing 1641 * what the verification tag could be, so we ignore it. 1642 * 1643 * Inputs 1644 * (endpoint, asoc, chunk) 1645 * 1646 * Outputs 1647 * (asoc, reply_msg, msg_up, timers, counters) 1648 * 1649 * The return value is the disposition of the chunk. 1650 */ 1651 sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net, 1652 const struct sctp_endpoint *ep, 1653 const struct sctp_association *asoc, 1654 const sctp_subtype_t type, 1655 void *arg, 1656 sctp_cmd_seq_t *commands) 1657 { 1658 /* Call helper to do the real work for both simulataneous and 1659 * duplicate INIT chunk handling. 1660 */ 1661 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1662 } 1663 1664 1665 /* 1666 * Unexpected INIT-ACK handler. 1667 * 1668 * Section 5.2.3 1669 * If an INIT ACK received by an endpoint in any state other than the 1670 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1671 * An unexpected INIT ACK usually indicates the processing of an old or 1672 * duplicated INIT chunk. 1673 */ 1674 sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net, 1675 const struct sctp_endpoint *ep, 1676 const struct sctp_association *asoc, 1677 const sctp_subtype_t type, 1678 void *arg, sctp_cmd_seq_t *commands) 1679 { 1680 /* Per the above section, we'll discard the chunk if we have an 1681 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1682 */ 1683 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1684 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1685 else 1686 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1687 } 1688 1689 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1690 * 1691 * Section 5.2.4 1692 * A) In this case, the peer may have restarted. 1693 */ 1694 static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net, 1695 const struct sctp_endpoint *ep, 1696 const struct sctp_association *asoc, 1697 struct sctp_chunk *chunk, 1698 sctp_cmd_seq_t *commands, 1699 struct sctp_association *new_asoc) 1700 { 1701 sctp_init_chunk_t *peer_init; 1702 struct sctp_ulpevent *ev; 1703 struct sctp_chunk *repl; 1704 struct sctp_chunk *err; 1705 sctp_disposition_t disposition; 1706 1707 /* new_asoc is a brand-new association, so these are not yet 1708 * side effects--it is safe to run them here. 1709 */ 1710 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1711 1712 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1713 GFP_ATOMIC)) 1714 goto nomem; 1715 1716 /* Make sure no new addresses are being added during the 1717 * restart. Though this is a pretty complicated attack 1718 * since you'd have to get inside the cookie. 1719 */ 1720 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { 1721 return SCTP_DISPOSITION_CONSUME; 1722 } 1723 1724 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1725 * the peer has restarted (Action A), it MUST NOT setup a new 1726 * association but instead resend the SHUTDOWN ACK and send an ERROR 1727 * chunk with a "Cookie Received while Shutting Down" error cause to 1728 * its peer. 1729 */ 1730 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1731 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1732 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1733 chunk, commands); 1734 if (SCTP_DISPOSITION_NOMEM == disposition) 1735 goto nomem; 1736 1737 err = sctp_make_op_error(asoc, chunk, 1738 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1739 NULL, 0, 0); 1740 if (err) 1741 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1742 SCTP_CHUNK(err)); 1743 1744 return SCTP_DISPOSITION_CONSUME; 1745 } 1746 1747 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1748 * data. Consider the optional choice of resending of this data. 1749 */ 1750 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1751 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1752 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1753 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1754 1755 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1756 * and ASCONF-ACK cache. 1757 */ 1758 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1759 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1760 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1761 1762 repl = sctp_make_cookie_ack(new_asoc, chunk); 1763 if (!repl) 1764 goto nomem; 1765 1766 /* Report association restart to upper layer. */ 1767 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1768 new_asoc->c.sinit_num_ostreams, 1769 new_asoc->c.sinit_max_instreams, 1770 NULL, GFP_ATOMIC); 1771 if (!ev) 1772 goto nomem_ev; 1773 1774 /* Update the content of current association. */ 1775 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1776 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1777 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1778 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1779 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1780 return SCTP_DISPOSITION_CONSUME; 1781 1782 nomem_ev: 1783 sctp_chunk_free(repl); 1784 nomem: 1785 return SCTP_DISPOSITION_NOMEM; 1786 } 1787 1788 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1789 * 1790 * Section 5.2.4 1791 * B) In this case, both sides may be attempting to start an association 1792 * at about the same time but the peer endpoint started its INIT 1793 * after responding to the local endpoint's INIT 1794 */ 1795 /* This case represents an initialization collision. */ 1796 static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, 1797 const struct sctp_endpoint *ep, 1798 const struct sctp_association *asoc, 1799 struct sctp_chunk *chunk, 1800 sctp_cmd_seq_t *commands, 1801 struct sctp_association *new_asoc) 1802 { 1803 sctp_init_chunk_t *peer_init; 1804 struct sctp_chunk *repl; 1805 1806 /* new_asoc is a brand-new association, so these are not yet 1807 * side effects--it is safe to run them here. 1808 */ 1809 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1810 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1811 GFP_ATOMIC)) 1812 goto nomem; 1813 1814 /* Update the content of current association. */ 1815 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); 1816 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1817 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1818 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1819 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1820 1821 repl = sctp_make_cookie_ack(new_asoc, chunk); 1822 if (!repl) 1823 goto nomem; 1824 1825 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1826 1827 /* RFC 2960 5.1 Normal Establishment of an Association 1828 * 1829 * D) IMPLEMENTATION NOTE: An implementation may choose to 1830 * send the Communication Up notification to the SCTP user 1831 * upon reception of a valid COOKIE ECHO chunk. 1832 * 1833 * Sadly, this needs to be implemented as a side-effect, because 1834 * we are not guaranteed to have set the association id of the real 1835 * association and so these notifications need to be delayed until 1836 * the association id is allocated. 1837 */ 1838 1839 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 1840 1841 /* Sockets API Draft Section 5.3.1.6 1842 * When a peer sends a Adaptation Layer Indication parameter , SCTP 1843 * delivers this notification to inform the application that of the 1844 * peers requested adaptation layer. 1845 * 1846 * This also needs to be done as a side effect for the same reason as 1847 * above. 1848 */ 1849 if (asoc->peer.adaptation_ind) 1850 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 1851 1852 return SCTP_DISPOSITION_CONSUME; 1853 1854 nomem: 1855 return SCTP_DISPOSITION_NOMEM; 1856 } 1857 1858 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 1859 * 1860 * Section 5.2.4 1861 * C) In this case, the local endpoint's cookie has arrived late. 1862 * Before it arrived, the local endpoint sent an INIT and received an 1863 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 1864 * but a new tag of its own. 1865 */ 1866 /* This case represents an initialization collision. */ 1867 static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net, 1868 const struct sctp_endpoint *ep, 1869 const struct sctp_association *asoc, 1870 struct sctp_chunk *chunk, 1871 sctp_cmd_seq_t *commands, 1872 struct sctp_association *new_asoc) 1873 { 1874 /* The cookie should be silently discarded. 1875 * The endpoint SHOULD NOT change states and should leave 1876 * any timers running. 1877 */ 1878 return SCTP_DISPOSITION_DISCARD; 1879 } 1880 1881 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 1882 * 1883 * Section 5.2.4 1884 * 1885 * D) When both local and remote tags match the endpoint should always 1886 * enter the ESTABLISHED state, if it has not already done so. 1887 */ 1888 /* This case represents an initialization collision. */ 1889 static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net, 1890 const struct sctp_endpoint *ep, 1891 const struct sctp_association *asoc, 1892 struct sctp_chunk *chunk, 1893 sctp_cmd_seq_t *commands, 1894 struct sctp_association *new_asoc) 1895 { 1896 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL; 1897 struct sctp_chunk *repl; 1898 1899 /* Clarification from Implementor's Guide: 1900 * D) When both local and remote tags match the endpoint should 1901 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 1902 * It should stop any cookie timer that may be running and send 1903 * a COOKIE ACK. 1904 */ 1905 1906 /* Don't accidentally move back into established state. */ 1907 if (asoc->state < SCTP_STATE_ESTABLISHED) { 1908 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1909 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1910 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1911 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1912 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1913 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 1914 SCTP_NULL()); 1915 1916 /* RFC 2960 5.1 Normal Establishment of an Association 1917 * 1918 * D) IMPLEMENTATION NOTE: An implementation may choose 1919 * to send the Communication Up notification to the 1920 * SCTP user upon reception of a valid COOKIE 1921 * ECHO chunk. 1922 */ 1923 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 1924 SCTP_COMM_UP, 0, 1925 asoc->c.sinit_num_ostreams, 1926 asoc->c.sinit_max_instreams, 1927 NULL, GFP_ATOMIC); 1928 if (!ev) 1929 goto nomem; 1930 1931 /* Sockets API Draft Section 5.3.1.6 1932 * When a peer sends a Adaptation Layer Indication parameter, 1933 * SCTP delivers this notification to inform the application 1934 * that of the peers requested adaptation layer. 1935 */ 1936 if (asoc->peer.adaptation_ind) { 1937 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 1938 GFP_ATOMIC); 1939 if (!ai_ev) 1940 goto nomem; 1941 1942 } 1943 } 1944 1945 repl = sctp_make_cookie_ack(new_asoc, chunk); 1946 if (!repl) 1947 goto nomem; 1948 1949 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1950 1951 if (ev) 1952 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1953 SCTP_ULPEVENT(ev)); 1954 if (ai_ev) 1955 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1956 SCTP_ULPEVENT(ai_ev)); 1957 1958 return SCTP_DISPOSITION_CONSUME; 1959 1960 nomem: 1961 if (ai_ev) 1962 sctp_ulpevent_free(ai_ev); 1963 if (ev) 1964 sctp_ulpevent_free(ev); 1965 return SCTP_DISPOSITION_NOMEM; 1966 } 1967 1968 /* 1969 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 1970 * chunk was retransmitted and then delayed in the network. 1971 * 1972 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 1973 * 1974 * Verification Tag: None. Do cookie validation. 1975 * 1976 * Inputs 1977 * (endpoint, asoc, chunk) 1978 * 1979 * Outputs 1980 * (asoc, reply_msg, msg_up, timers, counters) 1981 * 1982 * The return value is the disposition of the chunk. 1983 */ 1984 sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net, 1985 const struct sctp_endpoint *ep, 1986 const struct sctp_association *asoc, 1987 const sctp_subtype_t type, 1988 void *arg, 1989 sctp_cmd_seq_t *commands) 1990 { 1991 sctp_disposition_t retval; 1992 struct sctp_chunk *chunk = arg; 1993 struct sctp_association *new_asoc; 1994 int error = 0; 1995 char action; 1996 struct sctp_chunk *err_chk_p; 1997 1998 /* Make sure that the chunk has a valid length from the protocol 1999 * perspective. In this case check to make sure we have at least 2000 * enough for the chunk header. Cookie length verification is 2001 * done later. 2002 */ 2003 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2004 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2005 commands); 2006 2007 /* "Decode" the chunk. We have no optional parameters so we 2008 * are in good shape. 2009 */ 2010 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2011 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2012 sizeof(sctp_chunkhdr_t))) 2013 goto nomem; 2014 2015 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2016 * of a duplicate COOKIE ECHO match the Verification Tags of the 2017 * current association, consider the State Cookie valid even if 2018 * the lifespan is exceeded. 2019 */ 2020 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2021 &err_chk_p); 2022 2023 /* FIXME: 2024 * If the re-build failed, what is the proper error path 2025 * from here? 2026 * 2027 * [We should abort the association. --piggy] 2028 */ 2029 if (!new_asoc) { 2030 /* FIXME: Several errors are possible. A bad cookie should 2031 * be silently discarded, but think about logging it too. 2032 */ 2033 switch (error) { 2034 case -SCTP_IERROR_NOMEM: 2035 goto nomem; 2036 2037 case -SCTP_IERROR_STALE_COOKIE: 2038 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2039 err_chk_p); 2040 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2041 case -SCTP_IERROR_BAD_SIG: 2042 default: 2043 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2044 } 2045 } 2046 2047 /* Compare the tie_tag in cookie with the verification tag of 2048 * current association. 2049 */ 2050 action = sctp_tietags_compare(new_asoc, asoc); 2051 2052 switch (action) { 2053 case 'A': /* Association restart. */ 2054 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2055 new_asoc); 2056 break; 2057 2058 case 'B': /* Collision case B. */ 2059 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2060 new_asoc); 2061 break; 2062 2063 case 'C': /* Collision case C. */ 2064 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2065 new_asoc); 2066 break; 2067 2068 case 'D': /* Collision case D. */ 2069 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2070 new_asoc); 2071 break; 2072 2073 default: /* Discard packet for all others. */ 2074 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2075 break; 2076 } 2077 2078 /* Delete the tempory new association. */ 2079 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2080 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2081 2082 /* Restore association pointer to provide SCTP command interpeter 2083 * with a valid context in case it needs to manipulate 2084 * the queues */ 2085 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2086 SCTP_ASOC((struct sctp_association *)asoc)); 2087 2088 return retval; 2089 2090 nomem: 2091 return SCTP_DISPOSITION_NOMEM; 2092 } 2093 2094 /* 2095 * Process an ABORT. (SHUTDOWN-PENDING state) 2096 * 2097 * See sctp_sf_do_9_1_abort(). 2098 */ 2099 sctp_disposition_t sctp_sf_shutdown_pending_abort( 2100 struct net *net, 2101 const struct sctp_endpoint *ep, 2102 const struct sctp_association *asoc, 2103 const sctp_subtype_t type, 2104 void *arg, 2105 sctp_cmd_seq_t *commands) 2106 { 2107 struct sctp_chunk *chunk = arg; 2108 2109 if (!sctp_vtag_verify_either(chunk, asoc)) 2110 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2111 2112 /* Make sure that the ABORT chunk has a valid length. 2113 * Since this is an ABORT chunk, we have to discard it 2114 * because of the following text: 2115 * RFC 2960, Section 3.3.7 2116 * If an endpoint receives an ABORT with a format error or for an 2117 * association that doesn't exist, it MUST silently discard it. 2118 * Because the length is "invalid", we can't really discard just 2119 * as we do not know its true length. So, to be safe, discard the 2120 * packet. 2121 */ 2122 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2123 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2124 2125 /* ADD-IP: Special case for ABORT chunks 2126 * F4) One special consideration is that ABORT Chunks arriving 2127 * destined to the IP address being deleted MUST be 2128 * ignored (see Section 5.3.1 for further details). 2129 */ 2130 if (SCTP_ADDR_DEL == 2131 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2132 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2133 2134 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2135 } 2136 2137 /* 2138 * Process an ABORT. (SHUTDOWN-SENT state) 2139 * 2140 * See sctp_sf_do_9_1_abort(). 2141 */ 2142 sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net, 2143 const struct sctp_endpoint *ep, 2144 const struct sctp_association *asoc, 2145 const sctp_subtype_t type, 2146 void *arg, 2147 sctp_cmd_seq_t *commands) 2148 { 2149 struct sctp_chunk *chunk = arg; 2150 2151 if (!sctp_vtag_verify_either(chunk, asoc)) 2152 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2153 2154 /* Make sure that the ABORT chunk has a valid length. 2155 * Since this is an ABORT chunk, we have to discard it 2156 * because of the following text: 2157 * RFC 2960, Section 3.3.7 2158 * If an endpoint receives an ABORT with a format error or for an 2159 * association that doesn't exist, it MUST silently discard it. 2160 * Because the length is "invalid", we can't really discard just 2161 * as we do not know its true length. So, to be safe, discard the 2162 * packet. 2163 */ 2164 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2165 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2166 2167 /* ADD-IP: Special case for ABORT chunks 2168 * F4) One special consideration is that ABORT Chunks arriving 2169 * destined to the IP address being deleted MUST be 2170 * ignored (see Section 5.3.1 for further details). 2171 */ 2172 if (SCTP_ADDR_DEL == 2173 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2174 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2175 2176 /* Stop the T2-shutdown timer. */ 2177 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2178 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2179 2180 /* Stop the T5-shutdown guard timer. */ 2181 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2182 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2183 2184 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2185 } 2186 2187 /* 2188 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2189 * 2190 * See sctp_sf_do_9_1_abort(). 2191 */ 2192 sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( 2193 struct net *net, 2194 const struct sctp_endpoint *ep, 2195 const struct sctp_association *asoc, 2196 const sctp_subtype_t type, 2197 void *arg, 2198 sctp_cmd_seq_t *commands) 2199 { 2200 /* The same T2 timer, so we should be able to use 2201 * common function with the SHUTDOWN-SENT state. 2202 */ 2203 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2204 } 2205 2206 /* 2207 * Handle an Error received in COOKIE_ECHOED state. 2208 * 2209 * Only handle the error type of stale COOKIE Error, the other errors will 2210 * be ignored. 2211 * 2212 * Inputs 2213 * (endpoint, asoc, chunk) 2214 * 2215 * Outputs 2216 * (asoc, reply_msg, msg_up, timers, counters) 2217 * 2218 * The return value is the disposition of the chunk. 2219 */ 2220 sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net, 2221 const struct sctp_endpoint *ep, 2222 const struct sctp_association *asoc, 2223 const sctp_subtype_t type, 2224 void *arg, 2225 sctp_cmd_seq_t *commands) 2226 { 2227 struct sctp_chunk *chunk = arg; 2228 sctp_errhdr_t *err; 2229 2230 if (!sctp_vtag_verify(chunk, asoc)) 2231 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2232 2233 /* Make sure that the ERROR chunk has a valid length. 2234 * The parameter walking depends on this as well. 2235 */ 2236 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 2237 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2238 commands); 2239 2240 /* Process the error here */ 2241 /* FUTURE FIXME: When PR-SCTP related and other optional 2242 * parms are emitted, this will have to change to handle multiple 2243 * errors. 2244 */ 2245 sctp_walk_errors(err, chunk->chunk_hdr) { 2246 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2247 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2248 arg, commands); 2249 } 2250 2251 /* It is possible to have malformed error causes, and that 2252 * will cause us to end the walk early. However, since 2253 * we are discarding the packet, there should be no adverse 2254 * affects. 2255 */ 2256 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2257 } 2258 2259 /* 2260 * Handle a Stale COOKIE Error 2261 * 2262 * Section: 5.2.6 Handle Stale COOKIE Error 2263 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2264 * one of the following three alternatives. 2265 * ... 2266 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2267 * Preservative parameter requesting an extension to the lifetime of 2268 * the State Cookie. When calculating the time extension, an 2269 * implementation SHOULD use the RTT information measured based on the 2270 * previous COOKIE ECHO / ERROR exchange, and should add no more 2271 * than 1 second beyond the measured RTT, due to long State Cookie 2272 * lifetimes making the endpoint more subject to a replay attack. 2273 * 2274 * Verification Tag: Not explicit, but safe to ignore. 2275 * 2276 * Inputs 2277 * (endpoint, asoc, chunk) 2278 * 2279 * Outputs 2280 * (asoc, reply_msg, msg_up, timers, counters) 2281 * 2282 * The return value is the disposition of the chunk. 2283 */ 2284 static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net, 2285 const struct sctp_endpoint *ep, 2286 const struct sctp_association *asoc, 2287 const sctp_subtype_t type, 2288 void *arg, 2289 sctp_cmd_seq_t *commands) 2290 { 2291 struct sctp_chunk *chunk = arg; 2292 time_t stale; 2293 sctp_cookie_preserve_param_t bht; 2294 sctp_errhdr_t *err; 2295 struct sctp_chunk *reply; 2296 struct sctp_bind_addr *bp; 2297 int attempts = asoc->init_err_counter + 1; 2298 2299 if (attempts > asoc->max_init_attempts) { 2300 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2301 SCTP_ERROR(ETIMEDOUT)); 2302 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2303 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2304 return SCTP_DISPOSITION_DELETE_TCB; 2305 } 2306 2307 err = (sctp_errhdr_t *)(chunk->skb->data); 2308 2309 /* When calculating the time extension, an implementation 2310 * SHOULD use the RTT information measured based on the 2311 * previous COOKIE ECHO / ERROR exchange, and should add no 2312 * more than 1 second beyond the measured RTT, due to long 2313 * State Cookie lifetimes making the endpoint more subject to 2314 * a replay attack. 2315 * Measure of Staleness's unit is usec. (1/1000000 sec) 2316 * Suggested Cookie Life-span Increment's unit is msec. 2317 * (1/1000 sec) 2318 * In general, if you use the suggested cookie life, the value 2319 * found in the field of measure of staleness should be doubled 2320 * to give ample time to retransmit the new cookie and thus 2321 * yield a higher probability of success on the reattempt. 2322 */ 2323 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t))); 2324 stale = (stale * 2) / 1000; 2325 2326 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2327 bht.param_hdr.length = htons(sizeof(bht)); 2328 bht.lifespan_increment = htonl(stale); 2329 2330 /* Build that new INIT chunk. */ 2331 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2332 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2333 if (!reply) 2334 goto nomem; 2335 2336 sctp_addto_chunk(reply, sizeof(bht), &bht); 2337 2338 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2339 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2340 2341 /* Stop pending T3-rtx and heartbeat timers */ 2342 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2343 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2344 2345 /* Delete non-primary peer ip addresses since we are transitioning 2346 * back to the COOKIE-WAIT state 2347 */ 2348 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2349 2350 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2351 * resend 2352 */ 2353 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2354 SCTP_TRANSPORT(asoc->peer.primary_path)); 2355 2356 /* Cast away the const modifier, as we want to just 2357 * rerun it through as a sideffect. 2358 */ 2359 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2360 2361 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2362 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2363 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2364 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2365 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2366 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2367 2368 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2369 2370 return SCTP_DISPOSITION_CONSUME; 2371 2372 nomem: 2373 return SCTP_DISPOSITION_NOMEM; 2374 } 2375 2376 /* 2377 * Process an ABORT. 2378 * 2379 * Section: 9.1 2380 * After checking the Verification Tag, the receiving endpoint shall 2381 * remove the association from its record, and shall report the 2382 * termination to its upper layer. 2383 * 2384 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2385 * B) Rules for packet carrying ABORT: 2386 * 2387 * - The endpoint shall always fill in the Verification Tag field of the 2388 * outbound packet with the destination endpoint's tag value if it 2389 * is known. 2390 * 2391 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2392 * MUST follow the procedure described in Section 8.4. 2393 * 2394 * - The receiver MUST accept the packet if the Verification Tag 2395 * matches either its own tag, OR the tag of its peer. Otherwise, the 2396 * receiver MUST silently discard the packet and take no further 2397 * action. 2398 * 2399 * Inputs 2400 * (endpoint, asoc, chunk) 2401 * 2402 * Outputs 2403 * (asoc, reply_msg, msg_up, timers, counters) 2404 * 2405 * The return value is the disposition of the chunk. 2406 */ 2407 sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net, 2408 const struct sctp_endpoint *ep, 2409 const struct sctp_association *asoc, 2410 const sctp_subtype_t type, 2411 void *arg, 2412 sctp_cmd_seq_t *commands) 2413 { 2414 struct sctp_chunk *chunk = arg; 2415 2416 if (!sctp_vtag_verify_either(chunk, asoc)) 2417 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2418 2419 /* Make sure that the ABORT chunk has a valid length. 2420 * Since this is an ABORT chunk, we have to discard it 2421 * because of the following text: 2422 * RFC 2960, Section 3.3.7 2423 * If an endpoint receives an ABORT with a format error or for an 2424 * association that doesn't exist, it MUST silently discard it. 2425 * Because the length is "invalid", we can't really discard just 2426 * as we do not know its true length. So, to be safe, discard the 2427 * packet. 2428 */ 2429 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2430 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2431 2432 /* ADD-IP: Special case for ABORT chunks 2433 * F4) One special consideration is that ABORT Chunks arriving 2434 * destined to the IP address being deleted MUST be 2435 * ignored (see Section 5.3.1 for further details). 2436 */ 2437 if (SCTP_ADDR_DEL == 2438 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2439 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2440 2441 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2442 } 2443 2444 static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net, 2445 const struct sctp_endpoint *ep, 2446 const struct sctp_association *asoc, 2447 const sctp_subtype_t type, 2448 void *arg, 2449 sctp_cmd_seq_t *commands) 2450 { 2451 struct sctp_chunk *chunk = arg; 2452 unsigned int len; 2453 __be16 error = SCTP_ERROR_NO_ERROR; 2454 2455 /* See if we have an error cause code in the chunk. */ 2456 len = ntohs(chunk->chunk_hdr->length); 2457 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) { 2458 2459 sctp_errhdr_t *err; 2460 sctp_walk_errors(err, chunk->chunk_hdr); 2461 if ((void *)err != (void *)chunk->chunk_end) 2462 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2463 2464 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2465 } 2466 2467 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2468 /* ASSOC_FAILED will DELETE_TCB. */ 2469 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2470 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2471 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2472 2473 return SCTP_DISPOSITION_ABORT; 2474 } 2475 2476 /* 2477 * Process an ABORT. (COOKIE-WAIT state) 2478 * 2479 * See sctp_sf_do_9_1_abort() above. 2480 */ 2481 sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net, 2482 const struct sctp_endpoint *ep, 2483 const struct sctp_association *asoc, 2484 const sctp_subtype_t type, 2485 void *arg, 2486 sctp_cmd_seq_t *commands) 2487 { 2488 struct sctp_chunk *chunk = arg; 2489 unsigned int len; 2490 __be16 error = SCTP_ERROR_NO_ERROR; 2491 2492 if (!sctp_vtag_verify_either(chunk, asoc)) 2493 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2494 2495 /* Make sure that the ABORT chunk has a valid length. 2496 * Since this is an ABORT chunk, we have to discard it 2497 * because of the following text: 2498 * RFC 2960, Section 3.3.7 2499 * If an endpoint receives an ABORT with a format error or for an 2500 * association that doesn't exist, it MUST silently discard it. 2501 * Because the length is "invalid", we can't really discard just 2502 * as we do not know its true length. So, to be safe, discard the 2503 * packet. 2504 */ 2505 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t))) 2506 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2507 2508 /* See if we have an error cause code in the chunk. */ 2509 len = ntohs(chunk->chunk_hdr->length); 2510 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2511 error = ((sctp_errhdr_t *)chunk->skb->data)->cause; 2512 2513 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2514 chunk->transport); 2515 } 2516 2517 /* 2518 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2519 */ 2520 sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net, 2521 const struct sctp_endpoint *ep, 2522 const struct sctp_association *asoc, 2523 const sctp_subtype_t type, 2524 void *arg, 2525 sctp_cmd_seq_t *commands) 2526 { 2527 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2528 ENOPROTOOPT, asoc, 2529 (struct sctp_transport *)arg); 2530 } 2531 2532 /* 2533 * Process an ABORT. (COOKIE-ECHOED state) 2534 */ 2535 sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net, 2536 const struct sctp_endpoint *ep, 2537 const struct sctp_association *asoc, 2538 const sctp_subtype_t type, 2539 void *arg, 2540 sctp_cmd_seq_t *commands) 2541 { 2542 /* There is a single T1 timer, so we should be able to use 2543 * common function with the COOKIE-WAIT state. 2544 */ 2545 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2546 } 2547 2548 /* 2549 * Stop T1 timer and abort association with "INIT failed". 2550 * 2551 * This is common code called by several sctp_sf_*_abort() functions above. 2552 */ 2553 static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net, 2554 sctp_cmd_seq_t *commands, 2555 __be16 error, int sk_err, 2556 const struct sctp_association *asoc, 2557 struct sctp_transport *transport) 2558 { 2559 pr_debug("%s: ABORT received (INIT)\n", __func__); 2560 2561 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2562 SCTP_STATE(SCTP_STATE_CLOSED)); 2563 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2564 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2565 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2566 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2567 /* CMD_INIT_FAILED will DELETE_TCB. */ 2568 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2569 SCTP_PERR(error)); 2570 2571 return SCTP_DISPOSITION_ABORT; 2572 } 2573 2574 /* 2575 * sctp_sf_do_9_2_shut 2576 * 2577 * Section: 9.2 2578 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2579 * - enter the SHUTDOWN-RECEIVED state, 2580 * 2581 * - stop accepting new data from its SCTP user 2582 * 2583 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2584 * that all its outstanding DATA chunks have been received by the 2585 * SHUTDOWN sender. 2586 * 2587 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2588 * send a SHUTDOWN in response to a ULP request. And should discard 2589 * subsequent SHUTDOWN chunks. 2590 * 2591 * If there are still outstanding DATA chunks left, the SHUTDOWN 2592 * receiver shall continue to follow normal data transmission 2593 * procedures defined in Section 6 until all outstanding DATA chunks 2594 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2595 * new data from its SCTP user. 2596 * 2597 * Verification Tag: 8.5 Verification Tag [Normal verification] 2598 * 2599 * Inputs 2600 * (endpoint, asoc, chunk) 2601 * 2602 * Outputs 2603 * (asoc, reply_msg, msg_up, timers, counters) 2604 * 2605 * The return value is the disposition of the chunk. 2606 */ 2607 sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net, 2608 const struct sctp_endpoint *ep, 2609 const struct sctp_association *asoc, 2610 const sctp_subtype_t type, 2611 void *arg, 2612 sctp_cmd_seq_t *commands) 2613 { 2614 struct sctp_chunk *chunk = arg; 2615 sctp_shutdownhdr_t *sdh; 2616 sctp_disposition_t disposition; 2617 struct sctp_ulpevent *ev; 2618 __u32 ctsn; 2619 2620 if (!sctp_vtag_verify(chunk, asoc)) 2621 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2622 2623 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2624 if (!sctp_chunk_length_valid(chunk, 2625 sizeof(struct sctp_shutdown_chunk_t))) 2626 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2627 commands); 2628 2629 /* Convert the elaborate header. */ 2630 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2631 skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); 2632 chunk->subh.shutdown_hdr = sdh; 2633 ctsn = ntohl(sdh->cum_tsn_ack); 2634 2635 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2636 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2637 asoc->ctsn_ack_point); 2638 2639 return SCTP_DISPOSITION_DISCARD; 2640 } 2641 2642 /* If Cumulative TSN Ack beyond the max tsn currently 2643 * send, terminating the association and respond to the 2644 * sender with an ABORT. 2645 */ 2646 if (!TSN_lt(ctsn, asoc->next_tsn)) 2647 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2648 2649 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2650 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2651 * inform the application that it should cease sending data. 2652 */ 2653 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2654 if (!ev) { 2655 disposition = SCTP_DISPOSITION_NOMEM; 2656 goto out; 2657 } 2658 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2659 2660 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2661 * - enter the SHUTDOWN-RECEIVED state, 2662 * - stop accepting new data from its SCTP user 2663 * 2664 * [This is implicit in the new state.] 2665 */ 2666 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2667 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2668 disposition = SCTP_DISPOSITION_CONSUME; 2669 2670 if (sctp_outq_is_empty(&asoc->outqueue)) { 2671 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2672 arg, commands); 2673 } 2674 2675 if (SCTP_DISPOSITION_NOMEM == disposition) 2676 goto out; 2677 2678 /* - verify, by checking the Cumulative TSN Ack field of the 2679 * chunk, that all its outstanding DATA chunks have been 2680 * received by the SHUTDOWN sender. 2681 */ 2682 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2683 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2684 2685 out: 2686 return disposition; 2687 } 2688 2689 /* 2690 * sctp_sf_do_9_2_shut_ctsn 2691 * 2692 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2693 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2694 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2695 * MUST be processed. 2696 */ 2697 sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net, 2698 const struct sctp_endpoint *ep, 2699 const struct sctp_association *asoc, 2700 const sctp_subtype_t type, 2701 void *arg, 2702 sctp_cmd_seq_t *commands) 2703 { 2704 struct sctp_chunk *chunk = arg; 2705 sctp_shutdownhdr_t *sdh; 2706 __u32 ctsn; 2707 2708 if (!sctp_vtag_verify(chunk, asoc)) 2709 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2710 2711 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2712 if (!sctp_chunk_length_valid(chunk, 2713 sizeof(struct sctp_shutdown_chunk_t))) 2714 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2715 commands); 2716 2717 sdh = (sctp_shutdownhdr_t *)chunk->skb->data; 2718 ctsn = ntohl(sdh->cum_tsn_ack); 2719 2720 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2721 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2722 asoc->ctsn_ack_point); 2723 2724 return SCTP_DISPOSITION_DISCARD; 2725 } 2726 2727 /* If Cumulative TSN Ack beyond the max tsn currently 2728 * send, terminating the association and respond to the 2729 * sender with an ABORT. 2730 */ 2731 if (!TSN_lt(ctsn, asoc->next_tsn)) 2732 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2733 2734 /* verify, by checking the Cumulative TSN Ack field of the 2735 * chunk, that all its outstanding DATA chunks have been 2736 * received by the SHUTDOWN sender. 2737 */ 2738 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2739 SCTP_BE32(sdh->cum_tsn_ack)); 2740 2741 return SCTP_DISPOSITION_CONSUME; 2742 } 2743 2744 /* RFC 2960 9.2 2745 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2746 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2747 * transport addresses (either in the IP addresses or in the INIT chunk) 2748 * that belong to this association, it should discard the INIT chunk and 2749 * retransmit the SHUTDOWN ACK chunk. 2750 */ 2751 sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net, 2752 const struct sctp_endpoint *ep, 2753 const struct sctp_association *asoc, 2754 const sctp_subtype_t type, 2755 void *arg, 2756 sctp_cmd_seq_t *commands) 2757 { 2758 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 2759 struct sctp_chunk *reply; 2760 2761 /* Make sure that the chunk has a valid length */ 2762 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 2763 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2764 commands); 2765 2766 /* Since we are not going to really process this INIT, there 2767 * is no point in verifying chunk boundries. Just generate 2768 * the SHUTDOWN ACK. 2769 */ 2770 reply = sctp_make_shutdown_ack(asoc, chunk); 2771 if (NULL == reply) 2772 goto nomem; 2773 2774 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2775 * the T2-SHUTDOWN timer. 2776 */ 2777 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 2778 2779 /* and restart the T2-shutdown timer. */ 2780 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2781 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2782 2783 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2784 2785 return SCTP_DISPOSITION_CONSUME; 2786 nomem: 2787 return SCTP_DISPOSITION_NOMEM; 2788 } 2789 2790 /* 2791 * sctp_sf_do_ecn_cwr 2792 * 2793 * Section: Appendix A: Explicit Congestion Notification 2794 * 2795 * CWR: 2796 * 2797 * RFC 2481 details a specific bit for a sender to send in the header of 2798 * its next outbound TCP segment to indicate to its peer that it has 2799 * reduced its congestion window. This is termed the CWR bit. For 2800 * SCTP the same indication is made by including the CWR chunk. 2801 * This chunk contains one data element, i.e. the TSN number that 2802 * was sent in the ECNE chunk. This element represents the lowest 2803 * TSN number in the datagram that was originally marked with the 2804 * CE bit. 2805 * 2806 * Verification Tag: 8.5 Verification Tag [Normal verification] 2807 * Inputs 2808 * (endpoint, asoc, chunk) 2809 * 2810 * Outputs 2811 * (asoc, reply_msg, msg_up, timers, counters) 2812 * 2813 * The return value is the disposition of the chunk. 2814 */ 2815 sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net, 2816 const struct sctp_endpoint *ep, 2817 const struct sctp_association *asoc, 2818 const sctp_subtype_t type, 2819 void *arg, 2820 sctp_cmd_seq_t *commands) 2821 { 2822 sctp_cwrhdr_t *cwr; 2823 struct sctp_chunk *chunk = arg; 2824 u32 lowest_tsn; 2825 2826 if (!sctp_vtag_verify(chunk, asoc)) 2827 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2828 2829 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2830 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2831 commands); 2832 2833 cwr = (sctp_cwrhdr_t *) chunk->skb->data; 2834 skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); 2835 2836 lowest_tsn = ntohl(cwr->lowest_tsn); 2837 2838 /* Does this CWR ack the last sent congestion notification? */ 2839 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 2840 /* Stop sending ECNE. */ 2841 sctp_add_cmd_sf(commands, 2842 SCTP_CMD_ECN_CWR, 2843 SCTP_U32(lowest_tsn)); 2844 } 2845 return SCTP_DISPOSITION_CONSUME; 2846 } 2847 2848 /* 2849 * sctp_sf_do_ecne 2850 * 2851 * Section: Appendix A: Explicit Congestion Notification 2852 * 2853 * ECN-Echo 2854 * 2855 * RFC 2481 details a specific bit for a receiver to send back in its 2856 * TCP acknowledgements to notify the sender of the Congestion 2857 * Experienced (CE) bit having arrived from the network. For SCTP this 2858 * same indication is made by including the ECNE chunk. This chunk 2859 * contains one data element, i.e. the lowest TSN associated with the IP 2860 * datagram marked with the CE bit..... 2861 * 2862 * Verification Tag: 8.5 Verification Tag [Normal verification] 2863 * Inputs 2864 * (endpoint, asoc, chunk) 2865 * 2866 * Outputs 2867 * (asoc, reply_msg, msg_up, timers, counters) 2868 * 2869 * The return value is the disposition of the chunk. 2870 */ 2871 sctp_disposition_t sctp_sf_do_ecne(struct net *net, 2872 const struct sctp_endpoint *ep, 2873 const struct sctp_association *asoc, 2874 const sctp_subtype_t type, 2875 void *arg, 2876 sctp_cmd_seq_t *commands) 2877 { 2878 sctp_ecnehdr_t *ecne; 2879 struct sctp_chunk *chunk = arg; 2880 2881 if (!sctp_vtag_verify(chunk, asoc)) 2882 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2883 2884 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t))) 2885 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2886 commands); 2887 2888 ecne = (sctp_ecnehdr_t *) chunk->skb->data; 2889 skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); 2890 2891 /* If this is a newer ECNE than the last CWR packet we sent out */ 2892 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 2893 SCTP_U32(ntohl(ecne->lowest_tsn))); 2894 2895 return SCTP_DISPOSITION_CONSUME; 2896 } 2897 2898 /* 2899 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 2900 * 2901 * The SCTP endpoint MUST always acknowledge the reception of each valid 2902 * DATA chunk. 2903 * 2904 * The guidelines on delayed acknowledgement algorithm specified in 2905 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 2906 * acknowledgement SHOULD be generated for at least every second packet 2907 * (not every second DATA chunk) received, and SHOULD be generated within 2908 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 2909 * situations it may be beneficial for an SCTP transmitter to be more 2910 * conservative than the algorithms detailed in this document allow. 2911 * However, an SCTP transmitter MUST NOT be more aggressive than the 2912 * following algorithms allow. 2913 * 2914 * A SCTP receiver MUST NOT generate more than one SACK for every 2915 * incoming packet, other than to update the offered window as the 2916 * receiving application consumes new data. 2917 * 2918 * Verification Tag: 8.5 Verification Tag [Normal verification] 2919 * 2920 * Inputs 2921 * (endpoint, asoc, chunk) 2922 * 2923 * Outputs 2924 * (asoc, reply_msg, msg_up, timers, counters) 2925 * 2926 * The return value is the disposition of the chunk. 2927 */ 2928 sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net, 2929 const struct sctp_endpoint *ep, 2930 const struct sctp_association *asoc, 2931 const sctp_subtype_t type, 2932 void *arg, 2933 sctp_cmd_seq_t *commands) 2934 { 2935 struct sctp_chunk *chunk = arg; 2936 sctp_arg_t force = SCTP_NOFORCE(); 2937 int error; 2938 2939 if (!sctp_vtag_verify(chunk, asoc)) { 2940 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 2941 SCTP_NULL()); 2942 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2943 } 2944 2945 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 2946 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2947 commands); 2948 2949 error = sctp_eat_data(asoc, chunk, commands ); 2950 switch (error) { 2951 case SCTP_IERROR_NO_ERROR: 2952 break; 2953 case SCTP_IERROR_HIGH_TSN: 2954 case SCTP_IERROR_BAD_STREAM: 2955 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2956 goto discard_noforce; 2957 case SCTP_IERROR_DUP_TSN: 2958 case SCTP_IERROR_IGNORE_TSN: 2959 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 2960 goto discard_force; 2961 case SCTP_IERROR_NO_DATA: 2962 goto consume; 2963 case SCTP_IERROR_PROTO_VIOLATION: 2964 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 2965 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 2966 default: 2967 BUG(); 2968 } 2969 2970 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 2971 force = SCTP_FORCE(); 2972 2973 if (asoc->autoclose) { 2974 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 2975 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 2976 } 2977 2978 /* If this is the last chunk in a packet, we need to count it 2979 * toward sack generation. Note that we need to SACK every 2980 * OTHER packet containing data chunks, EVEN IF WE DISCARD 2981 * THEM. We elect to NOT generate SACK's if the chunk fails 2982 * the verification tag test. 2983 * 2984 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 2985 * 2986 * The SCTP endpoint MUST always acknowledge the reception of 2987 * each valid DATA chunk. 2988 * 2989 * The guidelines on delayed acknowledgement algorithm 2990 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 2991 * Specifically, an acknowledgement SHOULD be generated for at 2992 * least every second packet (not every second DATA chunk) 2993 * received, and SHOULD be generated within 200 ms of the 2994 * arrival of any unacknowledged DATA chunk. In some 2995 * situations it may be beneficial for an SCTP transmitter to 2996 * be more conservative than the algorithms detailed in this 2997 * document allow. However, an SCTP transmitter MUST NOT be 2998 * more aggressive than the following algorithms allow. 2999 */ 3000 if (chunk->end_of_packet) 3001 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3002 3003 return SCTP_DISPOSITION_CONSUME; 3004 3005 discard_force: 3006 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3007 * 3008 * When a packet arrives with duplicate DATA chunk(s) and with 3009 * no new DATA chunk(s), the endpoint MUST immediately send a 3010 * SACK with no delay. If a packet arrives with duplicate 3011 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3012 * MAY immediately send a SACK. Normally receipt of duplicate 3013 * DATA chunks will occur when the original SACK chunk was lost 3014 * and the peer's RTO has expired. The duplicate TSN number(s) 3015 * SHOULD be reported in the SACK as duplicate. 3016 */ 3017 /* In our case, we split the MAY SACK advice up whether or not 3018 * the last chunk is a duplicate.' 3019 */ 3020 if (chunk->end_of_packet) 3021 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3022 return SCTP_DISPOSITION_DISCARD; 3023 3024 discard_noforce: 3025 if (chunk->end_of_packet) 3026 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3027 3028 return SCTP_DISPOSITION_DISCARD; 3029 consume: 3030 return SCTP_DISPOSITION_CONSUME; 3031 3032 } 3033 3034 /* 3035 * sctp_sf_eat_data_fast_4_4 3036 * 3037 * Section: 4 (4) 3038 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3039 * DATA chunks without delay. 3040 * 3041 * Verification Tag: 8.5 Verification Tag [Normal verification] 3042 * Inputs 3043 * (endpoint, asoc, chunk) 3044 * 3045 * Outputs 3046 * (asoc, reply_msg, msg_up, timers, counters) 3047 * 3048 * The return value is the disposition of the chunk. 3049 */ 3050 sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net, 3051 const struct sctp_endpoint *ep, 3052 const struct sctp_association *asoc, 3053 const sctp_subtype_t type, 3054 void *arg, 3055 sctp_cmd_seq_t *commands) 3056 { 3057 struct sctp_chunk *chunk = arg; 3058 int error; 3059 3060 if (!sctp_vtag_verify(chunk, asoc)) { 3061 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3062 SCTP_NULL()); 3063 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3064 } 3065 3066 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t))) 3067 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3068 commands); 3069 3070 error = sctp_eat_data(asoc, chunk, commands ); 3071 switch (error) { 3072 case SCTP_IERROR_NO_ERROR: 3073 case SCTP_IERROR_HIGH_TSN: 3074 case SCTP_IERROR_DUP_TSN: 3075 case SCTP_IERROR_IGNORE_TSN: 3076 case SCTP_IERROR_BAD_STREAM: 3077 break; 3078 case SCTP_IERROR_NO_DATA: 3079 goto consume; 3080 case SCTP_IERROR_PROTO_VIOLATION: 3081 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3082 (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t)); 3083 default: 3084 BUG(); 3085 } 3086 3087 /* Go a head and force a SACK, since we are shutting down. */ 3088 3089 /* Implementor's Guide. 3090 * 3091 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3092 * respond to each received packet containing one or more DATA chunk(s) 3093 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3094 */ 3095 if (chunk->end_of_packet) { 3096 /* We must delay the chunk creation since the cumulative 3097 * TSN has not been updated yet. 3098 */ 3099 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3100 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3101 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3102 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3103 } 3104 3105 consume: 3106 return SCTP_DISPOSITION_CONSUME; 3107 } 3108 3109 /* 3110 * Section: 6.2 Processing a Received SACK 3111 * D) Any time a SACK arrives, the endpoint performs the following: 3112 * 3113 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3114 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3115 * increasing, a SACK whose Cumulative TSN Ack is less than the 3116 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3117 * 3118 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3119 * of bytes still outstanding after processing the Cumulative TSN Ack 3120 * and the Gap Ack Blocks. 3121 * 3122 * iii) If the SACK is missing a TSN that was previously 3123 * acknowledged via a Gap Ack Block (e.g., the data receiver 3124 * reneged on the data), then mark the corresponding DATA chunk 3125 * as available for retransmit: Mark it as missing for fast 3126 * retransmit as described in Section 7.2.4 and if no retransmit 3127 * timer is running for the destination address to which the DATA 3128 * chunk was originally transmitted, then T3-rtx is started for 3129 * that destination address. 3130 * 3131 * Verification Tag: 8.5 Verification Tag [Normal verification] 3132 * 3133 * Inputs 3134 * (endpoint, asoc, chunk) 3135 * 3136 * Outputs 3137 * (asoc, reply_msg, msg_up, timers, counters) 3138 * 3139 * The return value is the disposition of the chunk. 3140 */ 3141 sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net, 3142 const struct sctp_endpoint *ep, 3143 const struct sctp_association *asoc, 3144 const sctp_subtype_t type, 3145 void *arg, 3146 sctp_cmd_seq_t *commands) 3147 { 3148 struct sctp_chunk *chunk = arg; 3149 sctp_sackhdr_t *sackh; 3150 __u32 ctsn; 3151 3152 if (!sctp_vtag_verify(chunk, asoc)) 3153 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3154 3155 /* Make sure that the SACK chunk has a valid length. */ 3156 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t))) 3157 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3158 commands); 3159 3160 /* Pull the SACK chunk from the data buffer */ 3161 sackh = sctp_sm_pull_sack(chunk); 3162 /* Was this a bogus SACK? */ 3163 if (!sackh) 3164 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3165 chunk->subh.sack_hdr = sackh; 3166 ctsn = ntohl(sackh->cum_tsn_ack); 3167 3168 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3169 * Ack Point, then drop the SACK. Since Cumulative TSN 3170 * Ack is monotonically increasing, a SACK whose 3171 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3172 * Point indicates an out-of-order SACK. 3173 */ 3174 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3175 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3176 asoc->ctsn_ack_point); 3177 3178 return SCTP_DISPOSITION_DISCARD; 3179 } 3180 3181 /* If Cumulative TSN Ack beyond the max tsn currently 3182 * send, terminating the association and respond to the 3183 * sender with an ABORT. 3184 */ 3185 if (!TSN_lt(ctsn, asoc->next_tsn)) 3186 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3187 3188 /* Return this SACK for further processing. */ 3189 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3190 3191 /* Note: We do the rest of the work on the PROCESS_SACK 3192 * sideeffect. 3193 */ 3194 return SCTP_DISPOSITION_CONSUME; 3195 } 3196 3197 /* 3198 * Generate an ABORT in response to a packet. 3199 * 3200 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3201 * 3202 * 8) The receiver should respond to the sender of the OOTB packet with 3203 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3204 * MUST fill in the Verification Tag field of the outbound packet 3205 * with the value found in the Verification Tag field of the OOTB 3206 * packet and set the T-bit in the Chunk Flags to indicate that the 3207 * Verification Tag is reflected. After sending this ABORT, the 3208 * receiver of the OOTB packet shall discard the OOTB packet and take 3209 * no further action. 3210 * 3211 * Verification Tag: 3212 * 3213 * The return value is the disposition of the chunk. 3214 */ 3215 static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net, 3216 const struct sctp_endpoint *ep, 3217 const struct sctp_association *asoc, 3218 const sctp_subtype_t type, 3219 void *arg, 3220 sctp_cmd_seq_t *commands) 3221 { 3222 struct sctp_packet *packet = NULL; 3223 struct sctp_chunk *chunk = arg; 3224 struct sctp_chunk *abort; 3225 3226 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3227 3228 if (packet) { 3229 /* Make an ABORT. The T bit will be set if the asoc 3230 * is NULL. 3231 */ 3232 abort = sctp_make_abort(asoc, chunk, 0); 3233 if (!abort) { 3234 sctp_ootb_pkt_free(packet); 3235 return SCTP_DISPOSITION_NOMEM; 3236 } 3237 3238 /* Reflect vtag if T-Bit is set */ 3239 if (sctp_test_T_bit(abort)) 3240 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3241 3242 /* Set the skb to the belonging sock for accounting. */ 3243 abort->skb->sk = ep->base.sk; 3244 3245 sctp_packet_append_chunk(packet, abort); 3246 3247 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3248 SCTP_PACKET(packet)); 3249 3250 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3251 3252 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3253 return SCTP_DISPOSITION_CONSUME; 3254 } 3255 3256 return SCTP_DISPOSITION_NOMEM; 3257 } 3258 3259 /* 3260 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3261 * event as ULP notification for each cause included in the chunk. 3262 * 3263 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3264 * 3265 * The return value is the disposition of the chunk. 3266 */ 3267 sctp_disposition_t sctp_sf_operr_notify(struct net *net, 3268 const struct sctp_endpoint *ep, 3269 const struct sctp_association *asoc, 3270 const sctp_subtype_t type, 3271 void *arg, 3272 sctp_cmd_seq_t *commands) 3273 { 3274 struct sctp_chunk *chunk = arg; 3275 sctp_errhdr_t *err; 3276 3277 if (!sctp_vtag_verify(chunk, asoc)) 3278 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3279 3280 /* Make sure that the ERROR chunk has a valid length. */ 3281 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t))) 3282 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3283 commands); 3284 sctp_walk_errors(err, chunk->chunk_hdr); 3285 if ((void *)err != (void *)chunk->chunk_end) 3286 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3287 (void *)err, commands); 3288 3289 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3290 SCTP_CHUNK(chunk)); 3291 3292 return SCTP_DISPOSITION_CONSUME; 3293 } 3294 3295 /* 3296 * Process an inbound SHUTDOWN ACK. 3297 * 3298 * From Section 9.2: 3299 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3300 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3301 * peer, and remove all record of the association. 3302 * 3303 * The return value is the disposition. 3304 */ 3305 sctp_disposition_t sctp_sf_do_9_2_final(struct net *net, 3306 const struct sctp_endpoint *ep, 3307 const struct sctp_association *asoc, 3308 const sctp_subtype_t type, 3309 void *arg, 3310 sctp_cmd_seq_t *commands) 3311 { 3312 struct sctp_chunk *chunk = arg; 3313 struct sctp_chunk *reply; 3314 struct sctp_ulpevent *ev; 3315 3316 if (!sctp_vtag_verify(chunk, asoc)) 3317 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3318 3319 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3320 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3321 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3322 commands); 3323 /* 10.2 H) SHUTDOWN COMPLETE notification 3324 * 3325 * When SCTP completes the shutdown procedures (section 9.2) this 3326 * notification is passed to the upper layer. 3327 */ 3328 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3329 0, 0, 0, NULL, GFP_ATOMIC); 3330 if (!ev) 3331 goto nomem; 3332 3333 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3334 reply = sctp_make_shutdown_complete(asoc, chunk); 3335 if (!reply) 3336 goto nomem_chunk; 3337 3338 /* Do all the commands now (after allocation), so that we 3339 * have consistent state if memory allocation failes 3340 */ 3341 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3342 3343 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3344 * stop the T2-shutdown timer, 3345 */ 3346 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3347 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3348 3349 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3350 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3351 3352 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3353 SCTP_STATE(SCTP_STATE_CLOSED)); 3354 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3355 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3356 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3357 3358 /* ...and remove all record of the association. */ 3359 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3360 return SCTP_DISPOSITION_DELETE_TCB; 3361 3362 nomem_chunk: 3363 sctp_ulpevent_free(ev); 3364 nomem: 3365 return SCTP_DISPOSITION_NOMEM; 3366 } 3367 3368 /* 3369 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3370 * 3371 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3372 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3373 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3374 * packet must fill in the Verification Tag field of the outbound 3375 * packet with the Verification Tag received in the SHUTDOWN ACK and 3376 * set the T-bit in the Chunk Flags to indicate that the Verification 3377 * Tag is reflected. 3378 * 3379 * 8) The receiver should respond to the sender of the OOTB packet with 3380 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3381 * MUST fill in the Verification Tag field of the outbound packet 3382 * with the value found in the Verification Tag field of the OOTB 3383 * packet and set the T-bit in the Chunk Flags to indicate that the 3384 * Verification Tag is reflected. After sending this ABORT, the 3385 * receiver of the OOTB packet shall discard the OOTB packet and take 3386 * no further action. 3387 */ 3388 sctp_disposition_t sctp_sf_ootb(struct net *net, 3389 const struct sctp_endpoint *ep, 3390 const struct sctp_association *asoc, 3391 const sctp_subtype_t type, 3392 void *arg, 3393 sctp_cmd_seq_t *commands) 3394 { 3395 struct sctp_chunk *chunk = arg; 3396 struct sk_buff *skb = chunk->skb; 3397 sctp_chunkhdr_t *ch; 3398 sctp_errhdr_t *err; 3399 __u8 *ch_end; 3400 int ootb_shut_ack = 0; 3401 int ootb_cookie_ack = 0; 3402 3403 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3404 3405 ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; 3406 do { 3407 /* Report violation if the chunk is less then minimal */ 3408 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 3409 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3410 commands); 3411 3412 /* Now that we know we at least have a chunk header, 3413 * do things that are type appropriate. 3414 */ 3415 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3416 ootb_shut_ack = 1; 3417 3418 /* RFC 2960, Section 3.3.7 3419 * Moreover, under any circumstances, an endpoint that 3420 * receives an ABORT MUST NOT respond to that ABORT by 3421 * sending an ABORT of its own. 3422 */ 3423 if (SCTP_CID_ABORT == ch->type) 3424 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3425 3426 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3427 * or a COOKIE ACK the SCTP Packet should be silently 3428 * discarded. 3429 */ 3430 3431 if (SCTP_CID_COOKIE_ACK == ch->type) 3432 ootb_cookie_ack = 1; 3433 3434 if (SCTP_CID_ERROR == ch->type) { 3435 sctp_walk_errors(err, ch) { 3436 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3437 ootb_cookie_ack = 1; 3438 break; 3439 } 3440 } 3441 } 3442 3443 /* Report violation if chunk len overflows */ 3444 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 3445 if (ch_end > skb_tail_pointer(skb)) 3446 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3447 commands); 3448 3449 ch = (sctp_chunkhdr_t *) ch_end; 3450 } while (ch_end < skb_tail_pointer(skb)); 3451 3452 if (ootb_shut_ack) 3453 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3454 else if (ootb_cookie_ack) 3455 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3456 else 3457 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3458 } 3459 3460 /* 3461 * Handle an "Out of the blue" SHUTDOWN ACK. 3462 * 3463 * Section: 8.4 5, sctpimpguide 2.41. 3464 * 3465 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3466 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3467 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3468 * packet must fill in the Verification Tag field of the outbound 3469 * packet with the Verification Tag received in the SHUTDOWN ACK and 3470 * set the T-bit in the Chunk Flags to indicate that the Verification 3471 * Tag is reflected. 3472 * 3473 * Inputs 3474 * (endpoint, asoc, type, arg, commands) 3475 * 3476 * Outputs 3477 * (sctp_disposition_t) 3478 * 3479 * The return value is the disposition of the chunk. 3480 */ 3481 static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net, 3482 const struct sctp_endpoint *ep, 3483 const struct sctp_association *asoc, 3484 const sctp_subtype_t type, 3485 void *arg, 3486 sctp_cmd_seq_t *commands) 3487 { 3488 struct sctp_packet *packet = NULL; 3489 struct sctp_chunk *chunk = arg; 3490 struct sctp_chunk *shut; 3491 3492 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3493 3494 if (packet) { 3495 /* Make an SHUTDOWN_COMPLETE. 3496 * The T bit will be set if the asoc is NULL. 3497 */ 3498 shut = sctp_make_shutdown_complete(asoc, chunk); 3499 if (!shut) { 3500 sctp_ootb_pkt_free(packet); 3501 return SCTP_DISPOSITION_NOMEM; 3502 } 3503 3504 /* Reflect vtag if T-Bit is set */ 3505 if (sctp_test_T_bit(shut)) 3506 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3507 3508 /* Set the skb to the belonging sock for accounting. */ 3509 shut->skb->sk = ep->base.sk; 3510 3511 sctp_packet_append_chunk(packet, shut); 3512 3513 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3514 SCTP_PACKET(packet)); 3515 3516 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3517 3518 /* If the chunk length is invalid, we don't want to process 3519 * the reset of the packet. 3520 */ 3521 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3522 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3523 3524 /* We need to discard the rest of the packet to prevent 3525 * potential bomming attacks from additional bundled chunks. 3526 * This is documented in SCTP Threats ID. 3527 */ 3528 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3529 } 3530 3531 return SCTP_DISPOSITION_NOMEM; 3532 } 3533 3534 /* 3535 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3536 * 3537 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3538 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3539 * procedures in section 8.4 SHOULD be followed, in other words it 3540 * should be treated as an Out Of The Blue packet. 3541 * [This means that we do NOT check the Verification Tag on these 3542 * chunks. --piggy ] 3543 * 3544 */ 3545 sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net, 3546 const struct sctp_endpoint *ep, 3547 const struct sctp_association *asoc, 3548 const sctp_subtype_t type, 3549 void *arg, 3550 sctp_cmd_seq_t *commands) 3551 { 3552 struct sctp_chunk *chunk = arg; 3553 3554 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3555 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 3556 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3557 commands); 3558 3559 /* Although we do have an association in this case, it corresponds 3560 * to a restarted association. So the packet is treated as an OOTB 3561 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3562 * called with a NULL association. 3563 */ 3564 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3565 3566 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3567 } 3568 3569 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3570 sctp_disposition_t sctp_sf_do_asconf(struct net *net, 3571 const struct sctp_endpoint *ep, 3572 const struct sctp_association *asoc, 3573 const sctp_subtype_t type, void *arg, 3574 sctp_cmd_seq_t *commands) 3575 { 3576 struct sctp_chunk *chunk = arg; 3577 struct sctp_chunk *asconf_ack = NULL; 3578 struct sctp_paramhdr *err_param = NULL; 3579 sctp_addiphdr_t *hdr; 3580 union sctp_addr_param *addr_param; 3581 __u32 serial; 3582 int length; 3583 3584 if (!sctp_vtag_verify(chunk, asoc)) { 3585 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3586 SCTP_NULL()); 3587 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3588 } 3589 3590 /* ADD-IP: Section 4.1.1 3591 * This chunk MUST be sent in an authenticated way by using 3592 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3593 * is received unauthenticated it MUST be silently discarded as 3594 * described in [I-D.ietf-tsvwg-sctp-auth]. 3595 */ 3596 if (!net->sctp.addip_noauth && !chunk->auth) 3597 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3598 3599 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3600 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t))) 3601 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3602 commands); 3603 3604 hdr = (sctp_addiphdr_t *)chunk->skb->data; 3605 serial = ntohl(hdr->serial); 3606 3607 addr_param = (union sctp_addr_param *)hdr->params; 3608 length = ntohs(addr_param->p.length); 3609 if (length < sizeof(sctp_paramhdr_t)) 3610 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3611 (void *)addr_param, commands); 3612 3613 /* Verify the ASCONF chunk before processing it. */ 3614 if (!sctp_verify_asconf(asoc, 3615 (sctp_paramhdr_t *)((void *)addr_param + length), 3616 (void *)chunk->chunk_end, 3617 &err_param)) 3618 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3619 (void *)err_param, commands); 3620 3621 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3622 * the endpoint stored in a new association variable 3623 * 'Peer-Serial-Number'. 3624 */ 3625 if (serial == asoc->peer.addip_serial + 1) { 3626 /* If this is the first instance of ASCONF in the packet, 3627 * we can clean our old ASCONF-ACKs. 3628 */ 3629 if (!chunk->has_asconf) 3630 sctp_assoc_clean_asconf_ack_cache(asoc); 3631 3632 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3633 * expected, process the ASCONF as described below and after 3634 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3635 * the response packet and cache a copy of it (in the event it 3636 * later needs to be retransmitted). 3637 * 3638 * Essentially, do V1-V5. 3639 */ 3640 asconf_ack = sctp_process_asconf((struct sctp_association *) 3641 asoc, chunk); 3642 if (!asconf_ack) 3643 return SCTP_DISPOSITION_NOMEM; 3644 } else if (serial < asoc->peer.addip_serial + 1) { 3645 /* ADDIP 5.2 E2) 3646 * If the value found in the Sequence Number is less than the 3647 * ('Peer- Sequence-Number' + 1), simply skip to the next 3648 * ASCONF, and include in the outbound response packet 3649 * any previously cached ASCONF-ACK response that was 3650 * sent and saved that matches the Sequence Number of the 3651 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3652 * Chunk exists. This will occur when an older ASCONF 3653 * arrives out of order. In such a case, the receiver 3654 * should skip the ASCONF Chunk and not include ASCONF-ACK 3655 * Chunk for that chunk. 3656 */ 3657 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3658 if (!asconf_ack) 3659 return SCTP_DISPOSITION_DISCARD; 3660 3661 /* Reset the transport so that we select the correct one 3662 * this time around. This is to make sure that we don't 3663 * accidentally use a stale transport that's been removed. 3664 */ 3665 asconf_ack->transport = NULL; 3666 } else { 3667 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3668 * it must be either a stale packet or from an attacker. 3669 */ 3670 return SCTP_DISPOSITION_DISCARD; 3671 } 3672 3673 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3674 * containing the ASCONF-ACK Chunks MUST be the source address of 3675 * the SCTP packet that held the ASCONF Chunks. 3676 * 3677 * To do this properly, we'll set the destination address of the chunk 3678 * and at the transmit time, will try look up the transport to use. 3679 * Since ASCONFs may be bundled, the correct transport may not be 3680 * created until we process the entire packet, thus this workaround. 3681 */ 3682 asconf_ack->dest = chunk->source; 3683 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3684 if (asoc->new_transport) { 3685 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, 3686 commands); 3687 ((struct sctp_association *)asoc)->new_transport = NULL; 3688 } 3689 3690 return SCTP_DISPOSITION_CONSUME; 3691 } 3692 3693 /* 3694 * ADDIP Section 4.3 General rules for address manipulation 3695 * When building TLV parameters for the ASCONF Chunk that will add or 3696 * delete IP addresses the D0 to D13 rules should be applied: 3697 */ 3698 sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net, 3699 const struct sctp_endpoint *ep, 3700 const struct sctp_association *asoc, 3701 const sctp_subtype_t type, void *arg, 3702 sctp_cmd_seq_t *commands) 3703 { 3704 struct sctp_chunk *asconf_ack = arg; 3705 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3706 struct sctp_chunk *abort; 3707 struct sctp_paramhdr *err_param = NULL; 3708 sctp_addiphdr_t *addip_hdr; 3709 __u32 sent_serial, rcvd_serial; 3710 3711 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3712 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3713 SCTP_NULL()); 3714 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3715 } 3716 3717 /* ADD-IP, Section 4.1.2: 3718 * This chunk MUST be sent in an authenticated way by using 3719 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3720 * is received unauthenticated it MUST be silently discarded as 3721 * described in [I-D.ietf-tsvwg-sctp-auth]. 3722 */ 3723 if (!net->sctp.addip_noauth && !asconf_ack->auth) 3724 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 3725 3726 /* Make sure that the ADDIP chunk has a valid length. */ 3727 if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t))) 3728 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3729 commands); 3730 3731 addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; 3732 rcvd_serial = ntohl(addip_hdr->serial); 3733 3734 /* Verify the ASCONF-ACK chunk before processing it. */ 3735 if (!sctp_verify_asconf(asoc, 3736 (sctp_paramhdr_t *)addip_hdr->params, 3737 (void *)asconf_ack->chunk_end, 3738 &err_param)) 3739 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3740 (void *)err_param, commands); 3741 3742 if (last_asconf) { 3743 addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; 3744 sent_serial = ntohl(addip_hdr->serial); 3745 } else { 3746 sent_serial = asoc->addip_serial - 1; 3747 } 3748 3749 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 3750 * equal to the next serial number to be used but no ASCONF chunk is 3751 * outstanding the endpoint MUST ABORT the association. Note that a 3752 * sequence number is greater than if it is no more than 2^^31-1 3753 * larger than the current sequence number (using serial arithmetic). 3754 */ 3755 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 3756 !(asoc->addip_last_asconf)) { 3757 abort = sctp_make_abort(asoc, asconf_ack, 3758 sizeof(sctp_errhdr_t)); 3759 if (abort) { 3760 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 3761 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3762 SCTP_CHUNK(abort)); 3763 } 3764 /* We are going to ABORT, so we might as well stop 3765 * processing the rest of the chunks in the packet. 3766 */ 3767 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3768 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3769 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3770 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3771 SCTP_ERROR(ECONNABORTED)); 3772 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3773 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3774 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3775 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3776 return SCTP_DISPOSITION_ABORT; 3777 } 3778 3779 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 3780 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3781 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 3782 3783 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 3784 asconf_ack)) { 3785 /* Successfully processed ASCONF_ACK. We can 3786 * release the next asconf if we have one. 3787 */ 3788 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF, 3789 SCTP_NULL()); 3790 return SCTP_DISPOSITION_CONSUME; 3791 } 3792 3793 abort = sctp_make_abort(asoc, asconf_ack, 3794 sizeof(sctp_errhdr_t)); 3795 if (abort) { 3796 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 3797 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 3798 SCTP_CHUNK(abort)); 3799 } 3800 /* We are going to ABORT, so we might as well stop 3801 * processing the rest of the chunks in the packet. 3802 */ 3803 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 3804 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 3805 SCTP_ERROR(ECONNABORTED)); 3806 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 3807 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 3808 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 3809 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3810 return SCTP_DISPOSITION_ABORT; 3811 } 3812 3813 return SCTP_DISPOSITION_DISCARD; 3814 } 3815 3816 /* 3817 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 3818 * 3819 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 3820 * its cumulative TSN point to the value carried in the FORWARD TSN 3821 * chunk, and then MUST further advance its cumulative TSN point locally 3822 * if possible. 3823 * After the above processing, the data receiver MUST stop reporting any 3824 * missing TSNs earlier than or equal to the new cumulative TSN point. 3825 * 3826 * Verification Tag: 8.5 Verification Tag [Normal verification] 3827 * 3828 * The return value is the disposition of the chunk. 3829 */ 3830 sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net, 3831 const struct sctp_endpoint *ep, 3832 const struct sctp_association *asoc, 3833 const sctp_subtype_t type, 3834 void *arg, 3835 sctp_cmd_seq_t *commands) 3836 { 3837 struct sctp_chunk *chunk = arg; 3838 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3839 struct sctp_fwdtsn_skip *skip; 3840 __u16 len; 3841 __u32 tsn; 3842 3843 if (!sctp_vtag_verify(chunk, asoc)) { 3844 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3845 SCTP_NULL()); 3846 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3847 } 3848 3849 /* Make sure that the FORWARD_TSN chunk has valid length. */ 3850 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3851 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3852 commands); 3853 3854 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3855 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3856 len = ntohs(chunk->chunk_hdr->length); 3857 len -= sizeof(struct sctp_chunkhdr); 3858 skb_pull(chunk->skb, len); 3859 3860 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3861 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3862 3863 /* The TSN is too high--silently discard the chunk and count on it 3864 * getting retransmitted later. 3865 */ 3866 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3867 goto discard_noforce; 3868 3869 /* Silently discard the chunk if stream-id is not valid */ 3870 sctp_walk_fwdtsn(skip, chunk) { 3871 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3872 goto discard_noforce; 3873 } 3874 3875 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3876 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3877 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3878 SCTP_CHUNK(chunk)); 3879 3880 /* Count this as receiving DATA. */ 3881 if (asoc->autoclose) { 3882 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3883 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3884 } 3885 3886 /* FIXME: For now send a SACK, but DATA processing may 3887 * send another. 3888 */ 3889 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 3890 3891 return SCTP_DISPOSITION_CONSUME; 3892 3893 discard_noforce: 3894 return SCTP_DISPOSITION_DISCARD; 3895 } 3896 3897 sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 3898 struct net *net, 3899 const struct sctp_endpoint *ep, 3900 const struct sctp_association *asoc, 3901 const sctp_subtype_t type, 3902 void *arg, 3903 sctp_cmd_seq_t *commands) 3904 { 3905 struct sctp_chunk *chunk = arg; 3906 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 3907 struct sctp_fwdtsn_skip *skip; 3908 __u16 len; 3909 __u32 tsn; 3910 3911 if (!sctp_vtag_verify(chunk, asoc)) { 3912 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3913 SCTP_NULL()); 3914 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3915 } 3916 3917 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 3918 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk))) 3919 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3920 commands); 3921 3922 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 3923 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 3924 len = ntohs(chunk->chunk_hdr->length); 3925 len -= sizeof(struct sctp_chunkhdr); 3926 skb_pull(chunk->skb, len); 3927 3928 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 3929 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 3930 3931 /* The TSN is too high--silently discard the chunk and count on it 3932 * getting retransmitted later. 3933 */ 3934 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 3935 goto gen_shutdown; 3936 3937 /* Silently discard the chunk if stream-id is not valid */ 3938 sctp_walk_fwdtsn(skip, chunk) { 3939 if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams) 3940 goto gen_shutdown; 3941 } 3942 3943 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 3944 if (len > sizeof(struct sctp_fwdtsn_hdr)) 3945 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 3946 SCTP_CHUNK(chunk)); 3947 3948 /* Go a head and force a SACK, since we are shutting down. */ 3949 gen_shutdown: 3950 /* Implementor's Guide. 3951 * 3952 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3953 * respond to each received packet containing one or more DATA chunk(s) 3954 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3955 */ 3956 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3957 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3958 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3959 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3960 3961 return SCTP_DISPOSITION_CONSUME; 3962 } 3963 3964 /* 3965 * SCTP-AUTH Section 6.3 Receiving authenticated chukns 3966 * 3967 * The receiver MUST use the HMAC algorithm indicated in the HMAC 3968 * Identifier field. If this algorithm was not specified by the 3969 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 3970 * during association setup, the AUTH chunk and all chunks after it MUST 3971 * be discarded and an ERROR chunk SHOULD be sent with the error cause 3972 * defined in Section 4.1. 3973 * 3974 * If an endpoint with no shared key receives a Shared Key Identifier 3975 * other than 0, it MUST silently discard all authenticated chunks. If 3976 * the endpoint has at least one endpoint pair shared key for the peer, 3977 * it MUST use the key specified by the Shared Key Identifier if a 3978 * key has been configured for that Shared Key Identifier. If no 3979 * endpoint pair shared key has been configured for that Shared Key 3980 * Identifier, all authenticated chunks MUST be silently discarded. 3981 * 3982 * Verification Tag: 8.5 Verification Tag [Normal verification] 3983 * 3984 * The return value is the disposition of the chunk. 3985 */ 3986 static sctp_ierror_t sctp_sf_authenticate(struct net *net, 3987 const struct sctp_endpoint *ep, 3988 const struct sctp_association *asoc, 3989 const sctp_subtype_t type, 3990 struct sctp_chunk *chunk) 3991 { 3992 struct sctp_authhdr *auth_hdr; 3993 struct sctp_hmac *hmac; 3994 unsigned int sig_len; 3995 __u16 key_id; 3996 __u8 *save_digest; 3997 __u8 *digest; 3998 3999 /* Pull in the auth header, so we can do some more verification */ 4000 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4001 chunk->subh.auth_hdr = auth_hdr; 4002 skb_pull(chunk->skb, sizeof(struct sctp_authhdr)); 4003 4004 /* Make sure that we support the HMAC algorithm from the auth 4005 * chunk. 4006 */ 4007 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4008 return SCTP_IERROR_AUTH_BAD_HMAC; 4009 4010 /* Make sure that the provided shared key identifier has been 4011 * configured 4012 */ 4013 key_id = ntohs(auth_hdr->shkey_id); 4014 if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id)) 4015 return SCTP_IERROR_AUTH_BAD_KEYID; 4016 4017 4018 /* Make sure that the length of the signature matches what 4019 * we expect. 4020 */ 4021 sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t); 4022 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4023 if (sig_len != hmac->hmac_len) 4024 return SCTP_IERROR_PROTO_VIOLATION; 4025 4026 /* Now that we've done validation checks, we can compute and 4027 * verify the hmac. The steps involved are: 4028 * 1. Save the digest from the chunk. 4029 * 2. Zero out the digest in the chunk. 4030 * 3. Compute the new digest 4031 * 4. Compare saved and new digests. 4032 */ 4033 digest = auth_hdr->hmac; 4034 skb_pull(chunk->skb, sig_len); 4035 4036 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4037 if (!save_digest) 4038 goto nomem; 4039 4040 memset(digest, 0, sig_len); 4041 4042 sctp_auth_calculate_hmac(asoc, chunk->skb, 4043 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4044 GFP_ATOMIC); 4045 4046 /* Discard the packet if the digests do not match */ 4047 if (memcmp(save_digest, digest, sig_len)) { 4048 kfree(save_digest); 4049 return SCTP_IERROR_BAD_SIG; 4050 } 4051 4052 kfree(save_digest); 4053 chunk->auth = 1; 4054 4055 return SCTP_IERROR_NO_ERROR; 4056 nomem: 4057 return SCTP_IERROR_NOMEM; 4058 } 4059 4060 sctp_disposition_t sctp_sf_eat_auth(struct net *net, 4061 const struct sctp_endpoint *ep, 4062 const struct sctp_association *asoc, 4063 const sctp_subtype_t type, 4064 void *arg, 4065 sctp_cmd_seq_t *commands) 4066 { 4067 struct sctp_authhdr *auth_hdr; 4068 struct sctp_chunk *chunk = arg; 4069 struct sctp_chunk *err_chunk; 4070 sctp_ierror_t error; 4071 4072 /* Make sure that the peer has AUTH capable */ 4073 if (!asoc->peer.auth_capable) 4074 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4075 4076 if (!sctp_vtag_verify(chunk, asoc)) { 4077 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4078 SCTP_NULL()); 4079 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4080 } 4081 4082 /* Make sure that the AUTH chunk has valid length. */ 4083 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4084 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4085 commands); 4086 4087 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4088 error = sctp_sf_authenticate(net, ep, asoc, type, chunk); 4089 switch (error) { 4090 case SCTP_IERROR_AUTH_BAD_HMAC: 4091 /* Generate the ERROR chunk and discard the rest 4092 * of the packet 4093 */ 4094 err_chunk = sctp_make_op_error(asoc, chunk, 4095 SCTP_ERROR_UNSUP_HMAC, 4096 &auth_hdr->hmac_id, 4097 sizeof(__u16), 0); 4098 if (err_chunk) { 4099 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4100 SCTP_CHUNK(err_chunk)); 4101 } 4102 /* Fall Through */ 4103 case SCTP_IERROR_AUTH_BAD_KEYID: 4104 case SCTP_IERROR_BAD_SIG: 4105 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4106 4107 case SCTP_IERROR_PROTO_VIOLATION: 4108 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4109 commands); 4110 4111 case SCTP_IERROR_NOMEM: 4112 return SCTP_DISPOSITION_NOMEM; 4113 4114 default: /* Prevent gcc warnings */ 4115 break; 4116 } 4117 4118 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4119 struct sctp_ulpevent *ev; 4120 4121 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4122 SCTP_AUTH_NEWKEY, GFP_ATOMIC); 4123 4124 if (!ev) 4125 return -ENOMEM; 4126 4127 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4128 SCTP_ULPEVENT(ev)); 4129 } 4130 4131 return SCTP_DISPOSITION_CONSUME; 4132 } 4133 4134 /* 4135 * Process an unknown chunk. 4136 * 4137 * Section: 3.2. Also, 2.1 in the implementor's guide. 4138 * 4139 * Chunk Types are encoded such that the highest-order two bits specify 4140 * the action that must be taken if the processing endpoint does not 4141 * recognize the Chunk Type. 4142 * 4143 * 00 - Stop processing this SCTP packet and discard it, do not process 4144 * any further chunks within it. 4145 * 4146 * 01 - Stop processing this SCTP packet and discard it, do not process 4147 * any further chunks within it, and report the unrecognized 4148 * chunk in an 'Unrecognized Chunk Type'. 4149 * 4150 * 10 - Skip this chunk and continue processing. 4151 * 4152 * 11 - Skip this chunk and continue processing, but report in an ERROR 4153 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4154 * 4155 * The return value is the disposition of the chunk. 4156 */ 4157 sctp_disposition_t sctp_sf_unk_chunk(struct net *net, 4158 const struct sctp_endpoint *ep, 4159 const struct sctp_association *asoc, 4160 const sctp_subtype_t type, 4161 void *arg, 4162 sctp_cmd_seq_t *commands) 4163 { 4164 struct sctp_chunk *unk_chunk = arg; 4165 struct sctp_chunk *err_chunk; 4166 sctp_chunkhdr_t *hdr; 4167 4168 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4169 4170 if (!sctp_vtag_verify(unk_chunk, asoc)) 4171 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4172 4173 /* Make sure that the chunk has a valid length. 4174 * Since we don't know the chunk type, we use a general 4175 * chunkhdr structure to make a comparison. 4176 */ 4177 if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t))) 4178 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4179 commands); 4180 4181 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4182 case SCTP_CID_ACTION_DISCARD: 4183 /* Discard the packet. */ 4184 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4185 break; 4186 case SCTP_CID_ACTION_DISCARD_ERR: 4187 /* Generate an ERROR chunk as response. */ 4188 hdr = unk_chunk->chunk_hdr; 4189 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4190 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4191 WORD_ROUND(ntohs(hdr->length)), 4192 0); 4193 if (err_chunk) { 4194 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4195 SCTP_CHUNK(err_chunk)); 4196 } 4197 4198 /* Discard the packet. */ 4199 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4200 return SCTP_DISPOSITION_CONSUME; 4201 break; 4202 case SCTP_CID_ACTION_SKIP: 4203 /* Skip the chunk. */ 4204 return SCTP_DISPOSITION_DISCARD; 4205 break; 4206 case SCTP_CID_ACTION_SKIP_ERR: 4207 /* Generate an ERROR chunk as response. */ 4208 hdr = unk_chunk->chunk_hdr; 4209 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4210 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4211 WORD_ROUND(ntohs(hdr->length)), 4212 0); 4213 if (err_chunk) { 4214 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4215 SCTP_CHUNK(err_chunk)); 4216 } 4217 /* Skip the chunk. */ 4218 return SCTP_DISPOSITION_CONSUME; 4219 break; 4220 default: 4221 break; 4222 } 4223 4224 return SCTP_DISPOSITION_DISCARD; 4225 } 4226 4227 /* 4228 * Discard the chunk. 4229 * 4230 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4231 * [Too numerous to mention...] 4232 * Verification Tag: No verification needed. 4233 * Inputs 4234 * (endpoint, asoc, chunk) 4235 * 4236 * Outputs 4237 * (asoc, reply_msg, msg_up, timers, counters) 4238 * 4239 * The return value is the disposition of the chunk. 4240 */ 4241 sctp_disposition_t sctp_sf_discard_chunk(struct net *net, 4242 const struct sctp_endpoint *ep, 4243 const struct sctp_association *asoc, 4244 const sctp_subtype_t type, 4245 void *arg, 4246 sctp_cmd_seq_t *commands) 4247 { 4248 struct sctp_chunk *chunk = arg; 4249 4250 /* Make sure that the chunk has a valid length. 4251 * Since we don't know the chunk type, we use a general 4252 * chunkhdr structure to make a comparison. 4253 */ 4254 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4255 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4256 commands); 4257 4258 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4259 4260 return SCTP_DISPOSITION_DISCARD; 4261 } 4262 4263 /* 4264 * Discard the whole packet. 4265 * 4266 * Section: 8.4 2) 4267 * 4268 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4269 * silently discard the OOTB packet and take no further action. 4270 * 4271 * Verification Tag: No verification necessary 4272 * 4273 * Inputs 4274 * (endpoint, asoc, chunk) 4275 * 4276 * Outputs 4277 * (asoc, reply_msg, msg_up, timers, counters) 4278 * 4279 * The return value is the disposition of the chunk. 4280 */ 4281 sctp_disposition_t sctp_sf_pdiscard(struct net *net, 4282 const struct sctp_endpoint *ep, 4283 const struct sctp_association *asoc, 4284 const sctp_subtype_t type, 4285 void *arg, 4286 sctp_cmd_seq_t *commands) 4287 { 4288 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4289 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4290 4291 return SCTP_DISPOSITION_CONSUME; 4292 } 4293 4294 4295 /* 4296 * The other end is violating protocol. 4297 * 4298 * Section: Not specified 4299 * Verification Tag: Not specified 4300 * Inputs 4301 * (endpoint, asoc, chunk) 4302 * 4303 * Outputs 4304 * (asoc, reply_msg, msg_up, timers, counters) 4305 * 4306 * We simply tag the chunk as a violation. The state machine will log 4307 * the violation and continue. 4308 */ 4309 sctp_disposition_t sctp_sf_violation(struct net *net, 4310 const struct sctp_endpoint *ep, 4311 const struct sctp_association *asoc, 4312 const sctp_subtype_t type, 4313 void *arg, 4314 sctp_cmd_seq_t *commands) 4315 { 4316 struct sctp_chunk *chunk = arg; 4317 4318 /* Make sure that the chunk has a valid length. */ 4319 if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t))) 4320 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4321 commands); 4322 4323 return SCTP_DISPOSITION_VIOLATION; 4324 } 4325 4326 /* 4327 * Common function to handle a protocol violation. 4328 */ 4329 static sctp_disposition_t sctp_sf_abort_violation( 4330 struct net *net, 4331 const struct sctp_endpoint *ep, 4332 const struct sctp_association *asoc, 4333 void *arg, 4334 sctp_cmd_seq_t *commands, 4335 const __u8 *payload, 4336 const size_t paylen) 4337 { 4338 struct sctp_packet *packet = NULL; 4339 struct sctp_chunk *chunk = arg; 4340 struct sctp_chunk *abort = NULL; 4341 4342 /* SCTP-AUTH, Section 6.3: 4343 * It should be noted that if the receiver wants to tear 4344 * down an association in an authenticated way only, the 4345 * handling of malformed packets should not result in 4346 * tearing down the association. 4347 * 4348 * This means that if we only want to abort associations 4349 * in an authenticated way (i.e AUTH+ABORT), then we 4350 * can't destroy this association just because the packet 4351 * was malformed. 4352 */ 4353 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4354 goto discard; 4355 4356 /* Make the abort chunk. */ 4357 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4358 if (!abort) 4359 goto nomem; 4360 4361 if (asoc) { 4362 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4363 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4364 !asoc->peer.i.init_tag) { 4365 sctp_initack_chunk_t *initack; 4366 4367 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 4368 if (!sctp_chunk_length_valid(chunk, 4369 sizeof(sctp_initack_chunk_t))) 4370 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4371 else { 4372 unsigned int inittag; 4373 4374 inittag = ntohl(initack->init_hdr.init_tag); 4375 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4376 SCTP_U32(inittag)); 4377 } 4378 } 4379 4380 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4381 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4382 4383 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4384 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4385 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4386 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4387 SCTP_ERROR(ECONNREFUSED)); 4388 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4389 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4390 } else { 4391 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4392 SCTP_ERROR(ECONNABORTED)); 4393 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4394 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4395 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4396 } 4397 } else { 4398 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4399 4400 if (!packet) 4401 goto nomem_pkt; 4402 4403 if (sctp_test_T_bit(abort)) 4404 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4405 4406 abort->skb->sk = ep->base.sk; 4407 4408 sctp_packet_append_chunk(packet, abort); 4409 4410 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4411 SCTP_PACKET(packet)); 4412 4413 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4414 } 4415 4416 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4417 4418 discard: 4419 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4420 return SCTP_DISPOSITION_ABORT; 4421 4422 nomem_pkt: 4423 sctp_chunk_free(abort); 4424 nomem: 4425 return SCTP_DISPOSITION_NOMEM; 4426 } 4427 4428 /* 4429 * Handle a protocol violation when the chunk length is invalid. 4430 * "Invalid" length is identified as smaller than the minimal length a 4431 * given chunk can be. For example, a SACK chunk has invalid length 4432 * if its length is set to be smaller than the size of sctp_sack_chunk_t. 4433 * 4434 * We inform the other end by sending an ABORT with a Protocol Violation 4435 * error code. 4436 * 4437 * Section: Not specified 4438 * Verification Tag: Nothing to do 4439 * Inputs 4440 * (endpoint, asoc, chunk) 4441 * 4442 * Outputs 4443 * (reply_msg, msg_up, counters) 4444 * 4445 * Generate an ABORT chunk and terminate the association. 4446 */ 4447 static sctp_disposition_t sctp_sf_violation_chunklen( 4448 struct net *net, 4449 const struct sctp_endpoint *ep, 4450 const struct sctp_association *asoc, 4451 const sctp_subtype_t type, 4452 void *arg, 4453 sctp_cmd_seq_t *commands) 4454 { 4455 static const char err_str[]="The following chunk had invalid length:"; 4456 4457 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4458 sizeof(err_str)); 4459 } 4460 4461 /* 4462 * Handle a protocol violation when the parameter length is invalid. 4463 * If the length is smaller than the minimum length of a given parameter, 4464 * or accumulated length in multi parameters exceeds the end of the chunk, 4465 * the length is considered as invalid. 4466 */ 4467 static sctp_disposition_t sctp_sf_violation_paramlen( 4468 struct net *net, 4469 const struct sctp_endpoint *ep, 4470 const struct sctp_association *asoc, 4471 const sctp_subtype_t type, 4472 void *arg, void *ext, 4473 sctp_cmd_seq_t *commands) 4474 { 4475 struct sctp_chunk *chunk = arg; 4476 struct sctp_paramhdr *param = ext; 4477 struct sctp_chunk *abort = NULL; 4478 4479 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4480 goto discard; 4481 4482 /* Make the abort chunk. */ 4483 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4484 if (!abort) 4485 goto nomem; 4486 4487 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4488 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4489 4490 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4491 SCTP_ERROR(ECONNABORTED)); 4492 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4493 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4494 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4495 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4496 4497 discard: 4498 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4499 return SCTP_DISPOSITION_ABORT; 4500 nomem: 4501 return SCTP_DISPOSITION_NOMEM; 4502 } 4503 4504 /* Handle a protocol violation when the peer trying to advance the 4505 * cumulative tsn ack to a point beyond the max tsn currently sent. 4506 * 4507 * We inform the other end by sending an ABORT with a Protocol Violation 4508 * error code. 4509 */ 4510 static sctp_disposition_t sctp_sf_violation_ctsn( 4511 struct net *net, 4512 const struct sctp_endpoint *ep, 4513 const struct sctp_association *asoc, 4514 const sctp_subtype_t type, 4515 void *arg, 4516 sctp_cmd_seq_t *commands) 4517 { 4518 static const char err_str[]="The cumulative tsn ack beyond the max tsn currently sent:"; 4519 4520 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4521 sizeof(err_str)); 4522 } 4523 4524 /* Handle protocol violation of an invalid chunk bundling. For example, 4525 * when we have an association and we receive bundled INIT-ACK, or 4526 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle" 4527 * statement from the specs. Additionally, there might be an attacker 4528 * on the path and we may not want to continue this communication. 4529 */ 4530 static sctp_disposition_t sctp_sf_violation_chunk( 4531 struct net *net, 4532 const struct sctp_endpoint *ep, 4533 const struct sctp_association *asoc, 4534 const sctp_subtype_t type, 4535 void *arg, 4536 sctp_cmd_seq_t *commands) 4537 { 4538 static const char err_str[]="The following chunk violates protocol:"; 4539 4540 if (!asoc) 4541 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4542 4543 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4544 sizeof(err_str)); 4545 } 4546 /*************************************************************************** 4547 * These are the state functions for handling primitive (Section 10) events. 4548 ***************************************************************************/ 4549 /* 4550 * sctp_sf_do_prm_asoc 4551 * 4552 * Section: 10.1 ULP-to-SCTP 4553 * B) Associate 4554 * 4555 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4556 * outbound stream count) 4557 * -> association id [,destination transport addr list] [,outbound stream 4558 * count] 4559 * 4560 * This primitive allows the upper layer to initiate an association to a 4561 * specific peer endpoint. 4562 * 4563 * The peer endpoint shall be specified by one of the transport addresses 4564 * which defines the endpoint (see Section 1.4). If the local SCTP 4565 * instance has not been initialized, the ASSOCIATE is considered an 4566 * error. 4567 * [This is not relevant for the kernel implementation since we do all 4568 * initialization at boot time. It we hadn't initialized we wouldn't 4569 * get anywhere near this code.] 4570 * 4571 * An association id, which is a local handle to the SCTP association, 4572 * will be returned on successful establishment of the association. If 4573 * SCTP is not able to open an SCTP association with the peer endpoint, 4574 * an error is returned. 4575 * [In the kernel implementation, the struct sctp_association needs to 4576 * be created BEFORE causing this primitive to run.] 4577 * 4578 * Other association parameters may be returned, including the 4579 * complete destination transport addresses of the peer as well as the 4580 * outbound stream count of the local endpoint. One of the transport 4581 * address from the returned destination addresses will be selected by 4582 * the local endpoint as default primary path for sending SCTP packets 4583 * to this peer. The returned "destination transport addr list" can 4584 * be used by the ULP to change the default primary path or to force 4585 * sending a packet to a specific transport address. [All of this 4586 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4587 * function.] 4588 * 4589 * Mandatory attributes: 4590 * 4591 * o local SCTP instance name - obtained from the INITIALIZE operation. 4592 * [This is the argument asoc.] 4593 * o destination transport addr - specified as one of the transport 4594 * addresses of the peer endpoint with which the association is to be 4595 * established. 4596 * [This is asoc->peer.active_path.] 4597 * o outbound stream count - the number of outbound streams the ULP 4598 * would like to open towards this peer endpoint. 4599 * [BUG: This is not currently implemented.] 4600 * Optional attributes: 4601 * 4602 * None. 4603 * 4604 * The return value is a disposition. 4605 */ 4606 sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net, 4607 const struct sctp_endpoint *ep, 4608 const struct sctp_association *asoc, 4609 const sctp_subtype_t type, 4610 void *arg, 4611 sctp_cmd_seq_t *commands) 4612 { 4613 struct sctp_chunk *repl; 4614 struct sctp_association* my_asoc; 4615 4616 /* The comment below says that we enter COOKIE-WAIT AFTER 4617 * sending the INIT, but that doesn't actually work in our 4618 * implementation... 4619 */ 4620 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4621 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4622 4623 /* RFC 2960 5.1 Normal Establishment of an Association 4624 * 4625 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4626 * must provide its Verification Tag (Tag_A) in the Initiate 4627 * Tag field. Tag_A SHOULD be a random number in the range of 4628 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4629 */ 4630 4631 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4632 if (!repl) 4633 goto nomem; 4634 4635 /* Choose transport for INIT. */ 4636 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4637 SCTP_CHUNK(repl)); 4638 4639 /* Cast away the const modifier, as we want to just 4640 * rerun it through as a sideffect. 4641 */ 4642 my_asoc = (struct sctp_association *)asoc; 4643 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4644 4645 /* After sending the INIT, "A" starts the T1-init timer and 4646 * enters the COOKIE-WAIT state. 4647 */ 4648 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4649 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4650 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4651 return SCTP_DISPOSITION_CONSUME; 4652 4653 nomem: 4654 return SCTP_DISPOSITION_NOMEM; 4655 } 4656 4657 /* 4658 * Process the SEND primitive. 4659 * 4660 * Section: 10.1 ULP-to-SCTP 4661 * E) Send 4662 * 4663 * Format: SEND(association id, buffer address, byte count [,context] 4664 * [,stream id] [,life time] [,destination transport address] 4665 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4666 * -> result 4667 * 4668 * This is the main method to send user data via SCTP. 4669 * 4670 * Mandatory attributes: 4671 * 4672 * o association id - local handle to the SCTP association 4673 * 4674 * o buffer address - the location where the user message to be 4675 * transmitted is stored; 4676 * 4677 * o byte count - The size of the user data in number of bytes; 4678 * 4679 * Optional attributes: 4680 * 4681 * o context - an optional 32 bit integer that will be carried in the 4682 * sending failure notification to the ULP if the transportation of 4683 * this User Message fails. 4684 * 4685 * o stream id - to indicate which stream to send the data on. If not 4686 * specified, stream 0 will be used. 4687 * 4688 * o life time - specifies the life time of the user data. The user data 4689 * will not be sent by SCTP after the life time expires. This 4690 * parameter can be used to avoid efforts to transmit stale 4691 * user messages. SCTP notifies the ULP if the data cannot be 4692 * initiated to transport (i.e. sent to the destination via SCTP's 4693 * send primitive) within the life time variable. However, the 4694 * user data will be transmitted if SCTP has attempted to transmit a 4695 * chunk before the life time expired. 4696 * 4697 * o destination transport address - specified as one of the destination 4698 * transport addresses of the peer endpoint to which this packet 4699 * should be sent. Whenever possible, SCTP should use this destination 4700 * transport address for sending the packets, instead of the current 4701 * primary path. 4702 * 4703 * o unorder flag - this flag, if present, indicates that the user 4704 * would like the data delivered in an unordered fashion to the peer 4705 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 4706 * message). 4707 * 4708 * o no-bundle flag - instructs SCTP not to bundle this user data with 4709 * other outbound DATA chunks. SCTP MAY still bundle even when 4710 * this flag is present, when faced with network congestion. 4711 * 4712 * o payload protocol-id - A 32 bit unsigned integer that is to be 4713 * passed to the peer indicating the type of payload protocol data 4714 * being transmitted. This value is passed as opaque data by SCTP. 4715 * 4716 * The return value is the disposition. 4717 */ 4718 sctp_disposition_t sctp_sf_do_prm_send(struct net *net, 4719 const struct sctp_endpoint *ep, 4720 const struct sctp_association *asoc, 4721 const sctp_subtype_t type, 4722 void *arg, 4723 sctp_cmd_seq_t *commands) 4724 { 4725 struct sctp_datamsg *msg = arg; 4726 4727 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 4728 return SCTP_DISPOSITION_CONSUME; 4729 } 4730 4731 /* 4732 * Process the SHUTDOWN primitive. 4733 * 4734 * Section: 10.1: 4735 * C) Shutdown 4736 * 4737 * Format: SHUTDOWN(association id) 4738 * -> result 4739 * 4740 * Gracefully closes an association. Any locally queued user data 4741 * will be delivered to the peer. The association will be terminated only 4742 * after the peer acknowledges all the SCTP packets sent. A success code 4743 * will be returned on successful termination of the association. If 4744 * attempting to terminate the association results in a failure, an error 4745 * code shall be returned. 4746 * 4747 * Mandatory attributes: 4748 * 4749 * o association id - local handle to the SCTP association 4750 * 4751 * Optional attributes: 4752 * 4753 * None. 4754 * 4755 * The return value is the disposition. 4756 */ 4757 sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( 4758 struct net *net, 4759 const struct sctp_endpoint *ep, 4760 const struct sctp_association *asoc, 4761 const sctp_subtype_t type, 4762 void *arg, 4763 sctp_cmd_seq_t *commands) 4764 { 4765 int disposition; 4766 4767 /* From 9.2 Shutdown of an Association 4768 * Upon receipt of the SHUTDOWN primitive from its upper 4769 * layer, the endpoint enters SHUTDOWN-PENDING state and 4770 * remains there until all outstanding data has been 4771 * acknowledged by its peer. The endpoint accepts no new data 4772 * from its upper layer, but retransmits data to the far end 4773 * if necessary to fill gaps. 4774 */ 4775 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4776 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 4777 4778 disposition = SCTP_DISPOSITION_CONSUME; 4779 if (sctp_outq_is_empty(&asoc->outqueue)) { 4780 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 4781 arg, commands); 4782 } 4783 return disposition; 4784 } 4785 4786 /* 4787 * Process the ABORT primitive. 4788 * 4789 * Section: 10.1: 4790 * C) Abort 4791 * 4792 * Format: Abort(association id [, cause code]) 4793 * -> result 4794 * 4795 * Ungracefully closes an association. Any locally queued user data 4796 * will be discarded and an ABORT chunk is sent to the peer. A success code 4797 * will be returned on successful abortion of the association. If 4798 * attempting to abort the association results in a failure, an error 4799 * code shall be returned. 4800 * 4801 * Mandatory attributes: 4802 * 4803 * o association id - local handle to the SCTP association 4804 * 4805 * Optional attributes: 4806 * 4807 * o cause code - reason of the abort to be passed to the peer 4808 * 4809 * None. 4810 * 4811 * The return value is the disposition. 4812 */ 4813 sctp_disposition_t sctp_sf_do_9_1_prm_abort( 4814 struct net *net, 4815 const struct sctp_endpoint *ep, 4816 const struct sctp_association *asoc, 4817 const sctp_subtype_t type, 4818 void *arg, 4819 sctp_cmd_seq_t *commands) 4820 { 4821 /* From 9.1 Abort of an Association 4822 * Upon receipt of the ABORT primitive from its upper 4823 * layer, the endpoint enters CLOSED state and 4824 * discard all outstanding data has been 4825 * acknowledged by its peer. The endpoint accepts no new data 4826 * from its upper layer, but retransmits data to the far end 4827 * if necessary to fill gaps. 4828 */ 4829 struct sctp_chunk *abort = arg; 4830 sctp_disposition_t retval; 4831 4832 retval = SCTP_DISPOSITION_CONSUME; 4833 4834 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4835 4836 /* Even if we can't send the ABORT due to low memory delete the 4837 * TCB. This is a departure from our typical NOMEM handling. 4838 */ 4839 4840 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4841 SCTP_ERROR(ECONNABORTED)); 4842 /* Delete the established association. */ 4843 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4844 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4845 4846 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4847 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4848 4849 return retval; 4850 } 4851 4852 /* We tried an illegal operation on an association which is closed. */ 4853 sctp_disposition_t sctp_sf_error_closed(struct net *net, 4854 const struct sctp_endpoint *ep, 4855 const struct sctp_association *asoc, 4856 const sctp_subtype_t type, 4857 void *arg, 4858 sctp_cmd_seq_t *commands) 4859 { 4860 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 4861 return SCTP_DISPOSITION_CONSUME; 4862 } 4863 4864 /* We tried an illegal operation on an association which is shutting 4865 * down. 4866 */ 4867 sctp_disposition_t sctp_sf_error_shutdown(struct net *net, 4868 const struct sctp_endpoint *ep, 4869 const struct sctp_association *asoc, 4870 const sctp_subtype_t type, 4871 void *arg, 4872 sctp_cmd_seq_t *commands) 4873 { 4874 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 4875 SCTP_ERROR(-ESHUTDOWN)); 4876 return SCTP_DISPOSITION_CONSUME; 4877 } 4878 4879 /* 4880 * sctp_cookie_wait_prm_shutdown 4881 * 4882 * Section: 4 Note: 2 4883 * Verification Tag: 4884 * Inputs 4885 * (endpoint, asoc) 4886 * 4887 * The RFC does not explicitly address this issue, but is the route through the 4888 * state table when someone issues a shutdown while in COOKIE_WAIT state. 4889 * 4890 * Outputs 4891 * (timers) 4892 */ 4893 sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( 4894 struct net *net, 4895 const struct sctp_endpoint *ep, 4896 const struct sctp_association *asoc, 4897 const sctp_subtype_t type, 4898 void *arg, 4899 sctp_cmd_seq_t *commands) 4900 { 4901 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4902 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4903 4904 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4905 SCTP_STATE(SCTP_STATE_CLOSED)); 4906 4907 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 4908 4909 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 4910 4911 return SCTP_DISPOSITION_DELETE_TCB; 4912 } 4913 4914 /* 4915 * sctp_cookie_echoed_prm_shutdown 4916 * 4917 * Section: 4 Note: 2 4918 * Verification Tag: 4919 * Inputs 4920 * (endpoint, asoc) 4921 * 4922 * The RFC does not explcitly address this issue, but is the route through the 4923 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 4924 * 4925 * Outputs 4926 * (timers) 4927 */ 4928 sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( 4929 struct net *net, 4930 const struct sctp_endpoint *ep, 4931 const struct sctp_association *asoc, 4932 const sctp_subtype_t type, 4933 void *arg, sctp_cmd_seq_t *commands) 4934 { 4935 /* There is a single T1 timer, so we should be able to use 4936 * common function with the COOKIE-WAIT state. 4937 */ 4938 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 4939 } 4940 4941 /* 4942 * sctp_sf_cookie_wait_prm_abort 4943 * 4944 * Section: 4 Note: 2 4945 * Verification Tag: 4946 * Inputs 4947 * (endpoint, asoc) 4948 * 4949 * The RFC does not explicitly address this issue, but is the route through the 4950 * state table when someone issues an abort while in COOKIE_WAIT state. 4951 * 4952 * Outputs 4953 * (timers) 4954 */ 4955 sctp_disposition_t sctp_sf_cookie_wait_prm_abort( 4956 struct net *net, 4957 const struct sctp_endpoint *ep, 4958 const struct sctp_association *asoc, 4959 const sctp_subtype_t type, 4960 void *arg, 4961 sctp_cmd_seq_t *commands) 4962 { 4963 struct sctp_chunk *abort = arg; 4964 sctp_disposition_t retval; 4965 4966 /* Stop T1-init timer */ 4967 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4968 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4969 retval = SCTP_DISPOSITION_CONSUME; 4970 4971 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4972 4973 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4974 SCTP_STATE(SCTP_STATE_CLOSED)); 4975 4976 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4977 4978 /* Even if we can't send the ABORT due to low memory delete the 4979 * TCB. This is a departure from our typical NOMEM handling. 4980 */ 4981 4982 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4983 SCTP_ERROR(ECONNREFUSED)); 4984 /* Delete the established association. */ 4985 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4986 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 4987 4988 return retval; 4989 } 4990 4991 /* 4992 * sctp_sf_cookie_echoed_prm_abort 4993 * 4994 * Section: 4 Note: 3 4995 * Verification Tag: 4996 * Inputs 4997 * (endpoint, asoc) 4998 * 4999 * The RFC does not explcitly address this issue, but is the route through the 5000 * state table when someone issues an abort while in COOKIE_ECHOED state. 5001 * 5002 * Outputs 5003 * (timers) 5004 */ 5005 sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( 5006 struct net *net, 5007 const struct sctp_endpoint *ep, 5008 const struct sctp_association *asoc, 5009 const sctp_subtype_t type, 5010 void *arg, 5011 sctp_cmd_seq_t *commands) 5012 { 5013 /* There is a single T1 timer, so we should be able to use 5014 * common function with the COOKIE-WAIT state. 5015 */ 5016 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5017 } 5018 5019 /* 5020 * sctp_sf_shutdown_pending_prm_abort 5021 * 5022 * Inputs 5023 * (endpoint, asoc) 5024 * 5025 * The RFC does not explicitly address this issue, but is the route through the 5026 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5027 * 5028 * Outputs 5029 * (timers) 5030 */ 5031 sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( 5032 struct net *net, 5033 const struct sctp_endpoint *ep, 5034 const struct sctp_association *asoc, 5035 const sctp_subtype_t type, 5036 void *arg, 5037 sctp_cmd_seq_t *commands) 5038 { 5039 /* Stop the T5-shutdown guard timer. */ 5040 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5041 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5042 5043 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5044 } 5045 5046 /* 5047 * sctp_sf_shutdown_sent_prm_abort 5048 * 5049 * Inputs 5050 * (endpoint, asoc) 5051 * 5052 * The RFC does not explicitly address this issue, but is the route through the 5053 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5054 * 5055 * Outputs 5056 * (timers) 5057 */ 5058 sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( 5059 struct net *net, 5060 const struct sctp_endpoint *ep, 5061 const struct sctp_association *asoc, 5062 const sctp_subtype_t type, 5063 void *arg, 5064 sctp_cmd_seq_t *commands) 5065 { 5066 /* Stop the T2-shutdown timer. */ 5067 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5068 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5069 5070 /* Stop the T5-shutdown guard timer. */ 5071 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5072 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5073 5074 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5075 } 5076 5077 /* 5078 * sctp_sf_cookie_echoed_prm_abort 5079 * 5080 * Inputs 5081 * (endpoint, asoc) 5082 * 5083 * The RFC does not explcitly address this issue, but is the route through the 5084 * state table when someone issues an abort while in COOKIE_ECHOED state. 5085 * 5086 * Outputs 5087 * (timers) 5088 */ 5089 sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( 5090 struct net *net, 5091 const struct sctp_endpoint *ep, 5092 const struct sctp_association *asoc, 5093 const sctp_subtype_t type, 5094 void *arg, 5095 sctp_cmd_seq_t *commands) 5096 { 5097 /* The same T2 timer, so we should be able to use 5098 * common function with the SHUTDOWN-SENT state. 5099 */ 5100 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5101 } 5102 5103 /* 5104 * Process the REQUESTHEARTBEAT primitive 5105 * 5106 * 10.1 ULP-to-SCTP 5107 * J) Request Heartbeat 5108 * 5109 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5110 * 5111 * -> result 5112 * 5113 * Instructs the local endpoint to perform a HeartBeat on the specified 5114 * destination transport address of the given association. The returned 5115 * result should indicate whether the transmission of the HEARTBEAT 5116 * chunk to the destination address is successful. 5117 * 5118 * Mandatory attributes: 5119 * 5120 * o association id - local handle to the SCTP association 5121 * 5122 * o destination transport address - the transport address of the 5123 * association on which a heartbeat should be issued. 5124 */ 5125 sctp_disposition_t sctp_sf_do_prm_requestheartbeat( 5126 struct net *net, 5127 const struct sctp_endpoint *ep, 5128 const struct sctp_association *asoc, 5129 const sctp_subtype_t type, 5130 void *arg, 5131 sctp_cmd_seq_t *commands) 5132 { 5133 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5134 (struct sctp_transport *)arg, commands)) 5135 return SCTP_DISPOSITION_NOMEM; 5136 5137 /* 5138 * RFC 2960 (bis), section 8.3 5139 * 5140 * D) Request an on-demand HEARTBEAT on a specific destination 5141 * transport address of a given association. 5142 * 5143 * The endpoint should increment the respective error counter of 5144 * the destination transport address each time a HEARTBEAT is sent 5145 * to that address and not acknowledged within one RTO. 5146 * 5147 */ 5148 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5149 SCTP_TRANSPORT(arg)); 5150 return SCTP_DISPOSITION_CONSUME; 5151 } 5152 5153 /* 5154 * ADDIP Section 4.1 ASCONF Chunk Procedures 5155 * When an endpoint has an ASCONF signaled change to be sent to the 5156 * remote endpoint it should do A1 to A9 5157 */ 5158 sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net, 5159 const struct sctp_endpoint *ep, 5160 const struct sctp_association *asoc, 5161 const sctp_subtype_t type, 5162 void *arg, 5163 sctp_cmd_seq_t *commands) 5164 { 5165 struct sctp_chunk *chunk = arg; 5166 5167 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5168 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5169 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5170 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5171 return SCTP_DISPOSITION_CONSUME; 5172 } 5173 5174 /* 5175 * Ignore the primitive event 5176 * 5177 * The return value is the disposition of the primitive. 5178 */ 5179 sctp_disposition_t sctp_sf_ignore_primitive( 5180 struct net *net, 5181 const struct sctp_endpoint *ep, 5182 const struct sctp_association *asoc, 5183 const sctp_subtype_t type, 5184 void *arg, 5185 sctp_cmd_seq_t *commands) 5186 { 5187 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5188 type.primitive); 5189 5190 return SCTP_DISPOSITION_DISCARD; 5191 } 5192 5193 /*************************************************************************** 5194 * These are the state functions for the OTHER events. 5195 ***************************************************************************/ 5196 5197 /* 5198 * When the SCTP stack has no more user data to send or retransmit, this 5199 * notification is given to the user. Also, at the time when a user app 5200 * subscribes to this event, if there is no data to be sent or 5201 * retransmit, the stack will immediately send up this notification. 5202 */ 5203 sctp_disposition_t sctp_sf_do_no_pending_tsn( 5204 struct net *net, 5205 const struct sctp_endpoint *ep, 5206 const struct sctp_association *asoc, 5207 const sctp_subtype_t type, 5208 void *arg, 5209 sctp_cmd_seq_t *commands) 5210 { 5211 struct sctp_ulpevent *event; 5212 5213 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5214 if (!event) 5215 return SCTP_DISPOSITION_NOMEM; 5216 5217 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5218 5219 return SCTP_DISPOSITION_CONSUME; 5220 } 5221 5222 /* 5223 * Start the shutdown negotiation. 5224 * 5225 * From Section 9.2: 5226 * Once all its outstanding data has been acknowledged, the endpoint 5227 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5228 * TSN Ack field the last sequential TSN it has received from the peer. 5229 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5230 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5231 * with the updated last sequential TSN received from its peer. 5232 * 5233 * The return value is the disposition. 5234 */ 5235 sctp_disposition_t sctp_sf_do_9_2_start_shutdown( 5236 struct net *net, 5237 const struct sctp_endpoint *ep, 5238 const struct sctp_association *asoc, 5239 const sctp_subtype_t type, 5240 void *arg, 5241 sctp_cmd_seq_t *commands) 5242 { 5243 struct sctp_chunk *reply; 5244 5245 /* Once all its outstanding data has been acknowledged, the 5246 * endpoint shall send a SHUTDOWN chunk to its peer including 5247 * in the Cumulative TSN Ack field the last sequential TSN it 5248 * has received from the peer. 5249 */ 5250 reply = sctp_make_shutdown(asoc, NULL); 5251 if (!reply) 5252 goto nomem; 5253 5254 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5255 * T2-shutdown timer. 5256 */ 5257 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5258 5259 /* It shall then start the T2-shutdown timer */ 5260 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5261 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5262 5263 /* RFC 4960 Section 9.2 5264 * The sender of the SHUTDOWN MAY also start an overall guard timer 5265 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5266 */ 5267 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5268 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5269 5270 if (asoc->autoclose) 5271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5272 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5273 5274 /* and enter the SHUTDOWN-SENT state. */ 5275 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5276 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5277 5278 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5279 * 5280 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5281 * or SHUTDOWN-ACK. 5282 */ 5283 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5284 5285 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5286 5287 return SCTP_DISPOSITION_CONSUME; 5288 5289 nomem: 5290 return SCTP_DISPOSITION_NOMEM; 5291 } 5292 5293 /* 5294 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5295 * 5296 * From Section 9.2: 5297 * 5298 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5299 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5300 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5301 * endpoint must re-send the SHUTDOWN ACK. 5302 * 5303 * The return value is the disposition. 5304 */ 5305 sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( 5306 struct net *net, 5307 const struct sctp_endpoint *ep, 5308 const struct sctp_association *asoc, 5309 const sctp_subtype_t type, 5310 void *arg, 5311 sctp_cmd_seq_t *commands) 5312 { 5313 struct sctp_chunk *chunk = (struct sctp_chunk *) arg; 5314 struct sctp_chunk *reply; 5315 5316 /* There are 2 ways of getting here: 5317 * 1) called in response to a SHUTDOWN chunk 5318 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5319 * 5320 * For the case (2), the arg parameter is set to NULL. We need 5321 * to check that we have a chunk before accessing it's fields. 5322 */ 5323 if (chunk) { 5324 if (!sctp_vtag_verify(chunk, asoc)) 5325 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 5326 5327 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5328 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t))) 5329 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 5330 commands); 5331 } 5332 5333 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5334 * shall send a SHUTDOWN ACK ... 5335 */ 5336 reply = sctp_make_shutdown_ack(asoc, chunk); 5337 if (!reply) 5338 goto nomem; 5339 5340 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5341 * the T2-shutdown timer. 5342 */ 5343 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5344 5345 /* and start/restart a T2-shutdown timer of its own, */ 5346 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5347 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5348 5349 if (asoc->autoclose) 5350 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5351 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5352 5353 /* Enter the SHUTDOWN-ACK-SENT state. */ 5354 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5355 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5356 5357 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5358 * 5359 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5360 * or SHUTDOWN-ACK. 5361 */ 5362 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5363 5364 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5365 5366 return SCTP_DISPOSITION_CONSUME; 5367 5368 nomem: 5369 return SCTP_DISPOSITION_NOMEM; 5370 } 5371 5372 /* 5373 * Ignore the event defined as other 5374 * 5375 * The return value is the disposition of the event. 5376 */ 5377 sctp_disposition_t sctp_sf_ignore_other(struct net *net, 5378 const struct sctp_endpoint *ep, 5379 const struct sctp_association *asoc, 5380 const sctp_subtype_t type, 5381 void *arg, 5382 sctp_cmd_seq_t *commands) 5383 { 5384 pr_debug("%s: the event other type:%d is ignored\n", 5385 __func__, type.other); 5386 5387 return SCTP_DISPOSITION_DISCARD; 5388 } 5389 5390 /************************************************************ 5391 * These are the state functions for handling timeout events. 5392 ************************************************************/ 5393 5394 /* 5395 * RTX Timeout 5396 * 5397 * Section: 6.3.3 Handle T3-rtx Expiration 5398 * 5399 * Whenever the retransmission timer T3-rtx expires for a destination 5400 * address, do the following: 5401 * [See below] 5402 * 5403 * The return value is the disposition of the chunk. 5404 */ 5405 sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net, 5406 const struct sctp_endpoint *ep, 5407 const struct sctp_association *asoc, 5408 const sctp_subtype_t type, 5409 void *arg, 5410 sctp_cmd_seq_t *commands) 5411 { 5412 struct sctp_transport *transport = arg; 5413 5414 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5415 5416 if (asoc->overall_error_count >= asoc->max_retrans) { 5417 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5418 /* 5419 * We are here likely because the receiver had its rwnd 5420 * closed for a while and we have not been able to 5421 * transmit the locally queued data within the maximum 5422 * retransmission attempts limit. Start the T5 5423 * shutdown guard timer to give the receiver one last 5424 * chance and some additional time to recover before 5425 * aborting. 5426 */ 5427 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5428 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5429 } else { 5430 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5431 SCTP_ERROR(ETIMEDOUT)); 5432 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5433 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5434 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5435 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5436 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5437 return SCTP_DISPOSITION_DELETE_TCB; 5438 } 5439 } 5440 5441 /* E1) For the destination address for which the timer 5442 * expires, adjust its ssthresh with rules defined in Section 5443 * 7.2.3 and set the cwnd <- MTU. 5444 */ 5445 5446 /* E2) For the destination address for which the timer 5447 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5448 * maximum value discussed in rule C7 above (RTO.max) may be 5449 * used to provide an upper bound to this doubling operation. 5450 */ 5451 5452 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5453 * outstanding DATA chunks for the address for which the 5454 * T3-rtx has expired will fit into a single packet, subject 5455 * to the MTU constraint for the path corresponding to the 5456 * destination transport address to which the retransmission 5457 * is being sent (this may be different from the address for 5458 * which the timer expires [see Section 6.4]). Call this 5459 * value K. Bundle and retransmit those K DATA chunks in a 5460 * single packet to the destination endpoint. 5461 * 5462 * Note: Any DATA chunks that were sent to the address for 5463 * which the T3-rtx timer expired but did not fit in one MTU 5464 * (rule E3 above), should be marked for retransmission and 5465 * sent as soon as cwnd allows (normally when a SACK arrives). 5466 */ 5467 5468 /* Do some failure management (Section 8.2). */ 5469 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5470 5471 /* NB: Rules E4 and F1 are implicit in R1. */ 5472 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5473 5474 return SCTP_DISPOSITION_CONSUME; 5475 } 5476 5477 /* 5478 * Generate delayed SACK on timeout 5479 * 5480 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5481 * 5482 * The guidelines on delayed acknowledgement algorithm specified in 5483 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5484 * acknowledgement SHOULD be generated for at least every second packet 5485 * (not every second DATA chunk) received, and SHOULD be generated 5486 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5487 * some situations it may be beneficial for an SCTP transmitter to be 5488 * more conservative than the algorithms detailed in this document 5489 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5490 * the following algorithms allow. 5491 */ 5492 sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net, 5493 const struct sctp_endpoint *ep, 5494 const struct sctp_association *asoc, 5495 const sctp_subtype_t type, 5496 void *arg, 5497 sctp_cmd_seq_t *commands) 5498 { 5499 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5500 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5501 return SCTP_DISPOSITION_CONSUME; 5502 } 5503 5504 /* 5505 * sctp_sf_t1_init_timer_expire 5506 * 5507 * Section: 4 Note: 2 5508 * Verification Tag: 5509 * Inputs 5510 * (endpoint, asoc) 5511 * 5512 * RFC 2960 Section 4 Notes 5513 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5514 * and re-start the T1-init timer without changing state. This MUST 5515 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5516 * endpoint MUST abort the initialization process and report the 5517 * error to SCTP user. 5518 * 5519 * Outputs 5520 * (timers, events) 5521 * 5522 */ 5523 sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net, 5524 const struct sctp_endpoint *ep, 5525 const struct sctp_association *asoc, 5526 const sctp_subtype_t type, 5527 void *arg, 5528 sctp_cmd_seq_t *commands) 5529 { 5530 struct sctp_chunk *repl = NULL; 5531 struct sctp_bind_addr *bp; 5532 int attempts = asoc->init_err_counter + 1; 5533 5534 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5535 5536 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5537 5538 if (attempts <= asoc->max_init_attempts) { 5539 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5540 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5541 if (!repl) 5542 return SCTP_DISPOSITION_NOMEM; 5543 5544 /* Choose transport for INIT. */ 5545 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5546 SCTP_CHUNK(repl)); 5547 5548 /* Issue a sideeffect to do the needed accounting. */ 5549 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5550 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5551 5552 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5553 } else { 5554 pr_debug("%s: giving up on INIT, attempts:%d " 5555 "max_init_attempts:%d\n", __func__, attempts, 5556 asoc->max_init_attempts); 5557 5558 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5559 SCTP_ERROR(ETIMEDOUT)); 5560 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5561 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5562 return SCTP_DISPOSITION_DELETE_TCB; 5563 } 5564 5565 return SCTP_DISPOSITION_CONSUME; 5566 } 5567 5568 /* 5569 * sctp_sf_t1_cookie_timer_expire 5570 * 5571 * Section: 4 Note: 2 5572 * Verification Tag: 5573 * Inputs 5574 * (endpoint, asoc) 5575 * 5576 * RFC 2960 Section 4 Notes 5577 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5578 * COOKIE ECHO and re-start the T1-cookie timer without changing 5579 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5580 * After that, the endpoint MUST abort the initialization process and 5581 * report the error to SCTP user. 5582 * 5583 * Outputs 5584 * (timers, events) 5585 * 5586 */ 5587 sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net, 5588 const struct sctp_endpoint *ep, 5589 const struct sctp_association *asoc, 5590 const sctp_subtype_t type, 5591 void *arg, 5592 sctp_cmd_seq_t *commands) 5593 { 5594 struct sctp_chunk *repl = NULL; 5595 int attempts = asoc->init_err_counter + 1; 5596 5597 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5598 5599 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5600 5601 if (attempts <= asoc->max_init_attempts) { 5602 repl = sctp_make_cookie_echo(asoc, NULL); 5603 if (!repl) 5604 return SCTP_DISPOSITION_NOMEM; 5605 5606 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5607 SCTP_CHUNK(repl)); 5608 /* Issue a sideeffect to do the needed accounting. */ 5609 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5610 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5611 5612 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5613 } else { 5614 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5615 SCTP_ERROR(ETIMEDOUT)); 5616 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5617 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5618 return SCTP_DISPOSITION_DELETE_TCB; 5619 } 5620 5621 return SCTP_DISPOSITION_CONSUME; 5622 } 5623 5624 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5625 * with the updated last sequential TSN received from its peer. 5626 * 5627 * An endpoint should limit the number of retransmissions of the 5628 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5629 * If this threshold is exceeded the endpoint should destroy the TCB and 5630 * MUST report the peer endpoint unreachable to the upper layer (and 5631 * thus the association enters the CLOSED state). The reception of any 5632 * packet from its peer (i.e. as the peer sends all of its queued DATA 5633 * chunks) should clear the endpoint's retransmission count and restart 5634 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5635 * all of its queued DATA chunks that have not yet been sent. 5636 */ 5637 sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net, 5638 const struct sctp_endpoint *ep, 5639 const struct sctp_association *asoc, 5640 const sctp_subtype_t type, 5641 void *arg, 5642 sctp_cmd_seq_t *commands) 5643 { 5644 struct sctp_chunk *reply = NULL; 5645 5646 pr_debug("%s: timer T2 expired\n", __func__); 5647 5648 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5649 5650 ((struct sctp_association *)asoc)->shutdown_retries++; 5651 5652 if (asoc->overall_error_count >= asoc->max_retrans) { 5653 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5654 SCTP_ERROR(ETIMEDOUT)); 5655 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5656 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5657 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5658 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5659 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5660 return SCTP_DISPOSITION_DELETE_TCB; 5661 } 5662 5663 switch (asoc->state) { 5664 case SCTP_STATE_SHUTDOWN_SENT: 5665 reply = sctp_make_shutdown(asoc, NULL); 5666 break; 5667 5668 case SCTP_STATE_SHUTDOWN_ACK_SENT: 5669 reply = sctp_make_shutdown_ack(asoc, NULL); 5670 break; 5671 5672 default: 5673 BUG(); 5674 break; 5675 } 5676 5677 if (!reply) 5678 goto nomem; 5679 5680 /* Do some failure management (Section 8.2). 5681 * If we remove the transport an SHUTDOWN was last sent to, don't 5682 * do failure management. 5683 */ 5684 if (asoc->shutdown_last_sent_to) 5685 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5686 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 5687 5688 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 5689 * the T2-shutdown timer. 5690 */ 5691 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5692 5693 /* Restart the T2-shutdown timer. */ 5694 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5695 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5696 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5697 return SCTP_DISPOSITION_CONSUME; 5698 5699 nomem: 5700 return SCTP_DISPOSITION_NOMEM; 5701 } 5702 5703 /* 5704 * ADDIP Section 4.1 ASCONF CHunk Procedures 5705 * If the T4 RTO timer expires the endpoint should do B1 to B5 5706 */ 5707 sctp_disposition_t sctp_sf_t4_timer_expire( 5708 struct net *net, 5709 const struct sctp_endpoint *ep, 5710 const struct sctp_association *asoc, 5711 const sctp_subtype_t type, 5712 void *arg, 5713 sctp_cmd_seq_t *commands) 5714 { 5715 struct sctp_chunk *chunk = asoc->addip_last_asconf; 5716 struct sctp_transport *transport = chunk->transport; 5717 5718 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 5719 5720 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 5721 * detection on the appropriate destination address as defined in 5722 * RFC2960 [5] section 8.1 and 8.2. 5723 */ 5724 if (transport) 5725 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 5726 SCTP_TRANSPORT(transport)); 5727 5728 /* Reconfig T4 timer and transport. */ 5729 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5730 5731 /* ADDIP 4.1 B2) Increment the association error counters and perform 5732 * endpoint failure detection on the association as defined in 5733 * RFC2960 [5] section 8.1 and 8.2. 5734 * association error counter is incremented in SCTP_CMD_STRIKE. 5735 */ 5736 if (asoc->overall_error_count >= asoc->max_retrans) { 5737 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5738 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5739 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5740 SCTP_ERROR(ETIMEDOUT)); 5741 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5742 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5743 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5744 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5745 return SCTP_DISPOSITION_ABORT; 5746 } 5747 5748 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 5749 * the ASCONF chunk was sent by doubling the RTO timer value. 5750 * This is done in SCTP_CMD_STRIKE. 5751 */ 5752 5753 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 5754 * choose an alternate destination address (please refer to RFC2960 5755 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 5756 * chunk, it MUST be the same (including its serial number) as the last 5757 * ASCONF sent. 5758 */ 5759 sctp_chunk_hold(asoc->addip_last_asconf); 5760 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 5761 SCTP_CHUNK(asoc->addip_last_asconf)); 5762 5763 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 5764 * destination is selected, then the RTO used will be that of the new 5765 * destination address. 5766 */ 5767 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5768 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5769 5770 return SCTP_DISPOSITION_CONSUME; 5771 } 5772 5773 /* sctpimpguide-05 Section 2.12.2 5774 * The sender of the SHUTDOWN MAY also start an overall guard timer 5775 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5776 * At the expiration of this timer the sender SHOULD abort the association 5777 * by sending an ABORT chunk. 5778 */ 5779 sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net, 5780 const struct sctp_endpoint *ep, 5781 const struct sctp_association *asoc, 5782 const sctp_subtype_t type, 5783 void *arg, 5784 sctp_cmd_seq_t *commands) 5785 { 5786 struct sctp_chunk *reply = NULL; 5787 5788 pr_debug("%s: timer T5 expired\n", __func__); 5789 5790 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 5791 5792 reply = sctp_make_abort(asoc, NULL, 0); 5793 if (!reply) 5794 goto nomem; 5795 5796 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5797 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5798 SCTP_ERROR(ETIMEDOUT)); 5799 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5800 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5801 5802 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5803 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5804 5805 return SCTP_DISPOSITION_DELETE_TCB; 5806 nomem: 5807 return SCTP_DISPOSITION_NOMEM; 5808 } 5809 5810 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 5811 * the association is automatically closed by starting the shutdown process. 5812 * The work that needs to be done is same as when SHUTDOWN is initiated by 5813 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 5814 */ 5815 sctp_disposition_t sctp_sf_autoclose_timer_expire( 5816 struct net *net, 5817 const struct sctp_endpoint *ep, 5818 const struct sctp_association *asoc, 5819 const sctp_subtype_t type, 5820 void *arg, 5821 sctp_cmd_seq_t *commands) 5822 { 5823 int disposition; 5824 5825 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 5826 5827 /* From 9.2 Shutdown of an Association 5828 * Upon receipt of the SHUTDOWN primitive from its upper 5829 * layer, the endpoint enters SHUTDOWN-PENDING state and 5830 * remains there until all outstanding data has been 5831 * acknowledged by its peer. The endpoint accepts no new data 5832 * from its upper layer, but retransmits data to the far end 5833 * if necessary to fill gaps. 5834 */ 5835 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5836 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5837 5838 disposition = SCTP_DISPOSITION_CONSUME; 5839 if (sctp_outq_is_empty(&asoc->outqueue)) { 5840 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5841 arg, commands); 5842 } 5843 return disposition; 5844 } 5845 5846 /***************************************************************************** 5847 * These are sa state functions which could apply to all types of events. 5848 ****************************************************************************/ 5849 5850 /* 5851 * This table entry is not implemented. 5852 * 5853 * Inputs 5854 * (endpoint, asoc, chunk) 5855 * 5856 * The return value is the disposition of the chunk. 5857 */ 5858 sctp_disposition_t sctp_sf_not_impl(struct net *net, 5859 const struct sctp_endpoint *ep, 5860 const struct sctp_association *asoc, 5861 const sctp_subtype_t type, 5862 void *arg, 5863 sctp_cmd_seq_t *commands) 5864 { 5865 return SCTP_DISPOSITION_NOT_IMPL; 5866 } 5867 5868 /* 5869 * This table entry represents a bug. 5870 * 5871 * Inputs 5872 * (endpoint, asoc, chunk) 5873 * 5874 * The return value is the disposition of the chunk. 5875 */ 5876 sctp_disposition_t sctp_sf_bug(struct net *net, 5877 const struct sctp_endpoint *ep, 5878 const struct sctp_association *asoc, 5879 const sctp_subtype_t type, 5880 void *arg, 5881 sctp_cmd_seq_t *commands) 5882 { 5883 return SCTP_DISPOSITION_BUG; 5884 } 5885 5886 /* 5887 * This table entry represents the firing of a timer in the wrong state. 5888 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 5889 * when the association is in the wrong state. This event should 5890 * be ignored, so as to prevent any rearming of the timer. 5891 * 5892 * Inputs 5893 * (endpoint, asoc, chunk) 5894 * 5895 * The return value is the disposition of the chunk. 5896 */ 5897 sctp_disposition_t sctp_sf_timer_ignore(struct net *net, 5898 const struct sctp_endpoint *ep, 5899 const struct sctp_association *asoc, 5900 const sctp_subtype_t type, 5901 void *arg, 5902 sctp_cmd_seq_t *commands) 5903 { 5904 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 5905 5906 return SCTP_DISPOSITION_CONSUME; 5907 } 5908 5909 /******************************************************************** 5910 * 2nd Level Abstractions 5911 ********************************************************************/ 5912 5913 /* Pull the SACK chunk based on the SACK header. */ 5914 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 5915 { 5916 struct sctp_sackhdr *sack; 5917 unsigned int len; 5918 __u16 num_blocks; 5919 __u16 num_dup_tsns; 5920 5921 /* Protect ourselves from reading too far into 5922 * the skb from a bogus sender. 5923 */ 5924 sack = (struct sctp_sackhdr *) chunk->skb->data; 5925 5926 num_blocks = ntohs(sack->num_gap_ack_blocks); 5927 num_dup_tsns = ntohs(sack->num_dup_tsns); 5928 len = sizeof(struct sctp_sackhdr); 5929 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 5930 if (len > chunk->skb->len) 5931 return NULL; 5932 5933 skb_pull(chunk->skb, len); 5934 5935 return sack; 5936 } 5937 5938 /* Create an ABORT packet to be sent as a response, with the specified 5939 * error causes. 5940 */ 5941 static struct sctp_packet *sctp_abort_pkt_new(struct net *net, 5942 const struct sctp_endpoint *ep, 5943 const struct sctp_association *asoc, 5944 struct sctp_chunk *chunk, 5945 const void *payload, 5946 size_t paylen) 5947 { 5948 struct sctp_packet *packet; 5949 struct sctp_chunk *abort; 5950 5951 packet = sctp_ootb_pkt_new(net, asoc, chunk); 5952 5953 if (packet) { 5954 /* Make an ABORT. 5955 * The T bit will be set if the asoc is NULL. 5956 */ 5957 abort = sctp_make_abort(asoc, chunk, paylen); 5958 if (!abort) { 5959 sctp_ootb_pkt_free(packet); 5960 return NULL; 5961 } 5962 5963 /* Reflect vtag if T-Bit is set */ 5964 if (sctp_test_T_bit(abort)) 5965 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 5966 5967 /* Add specified error causes, i.e., payload, to the 5968 * end of the chunk. 5969 */ 5970 sctp_addto_chunk(abort, paylen, payload); 5971 5972 /* Set the skb to the belonging sock for accounting. */ 5973 abort->skb->sk = ep->base.sk; 5974 5975 sctp_packet_append_chunk(packet, abort); 5976 5977 } 5978 5979 return packet; 5980 } 5981 5982 /* Allocate a packet for responding in the OOTB conditions. */ 5983 static struct sctp_packet *sctp_ootb_pkt_new(struct net *net, 5984 const struct sctp_association *asoc, 5985 const struct sctp_chunk *chunk) 5986 { 5987 struct sctp_packet *packet; 5988 struct sctp_transport *transport; 5989 __u16 sport; 5990 __u16 dport; 5991 __u32 vtag; 5992 5993 /* Get the source and destination port from the inbound packet. */ 5994 sport = ntohs(chunk->sctp_hdr->dest); 5995 dport = ntohs(chunk->sctp_hdr->source); 5996 5997 /* The V-tag is going to be the same as the inbound packet if no 5998 * association exists, otherwise, use the peer's vtag. 5999 */ 6000 if (asoc) { 6001 /* Special case the INIT-ACK as there is no peer's vtag 6002 * yet. 6003 */ 6004 switch(chunk->chunk_hdr->type) { 6005 case SCTP_CID_INIT_ACK: 6006 { 6007 sctp_initack_chunk_t *initack; 6008 6009 initack = (sctp_initack_chunk_t *)chunk->chunk_hdr; 6010 vtag = ntohl(initack->init_hdr.init_tag); 6011 break; 6012 } 6013 default: 6014 vtag = asoc->peer.i.init_tag; 6015 break; 6016 } 6017 } else { 6018 /* Special case the INIT and stale COOKIE_ECHO as there is no 6019 * vtag yet. 6020 */ 6021 switch(chunk->chunk_hdr->type) { 6022 case SCTP_CID_INIT: 6023 { 6024 sctp_init_chunk_t *init; 6025 6026 init = (sctp_init_chunk_t *)chunk->chunk_hdr; 6027 vtag = ntohl(init->init_hdr.init_tag); 6028 break; 6029 } 6030 default: 6031 vtag = ntohl(chunk->sctp_hdr->vtag); 6032 break; 6033 } 6034 } 6035 6036 /* Make a transport for the bucket, Eliza... */ 6037 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6038 if (!transport) 6039 goto nomem; 6040 6041 /* Cache a route for the transport with the chunk's destination as 6042 * the source address. 6043 */ 6044 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6045 sctp_sk(net->sctp.ctl_sock)); 6046 6047 packet = sctp_packet_init(&transport->packet, transport, sport, dport); 6048 packet = sctp_packet_config(packet, vtag, 0); 6049 6050 return packet; 6051 6052 nomem: 6053 return NULL; 6054 } 6055 6056 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6057 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6058 { 6059 sctp_transport_free(packet->transport); 6060 } 6061 6062 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6063 static void sctp_send_stale_cookie_err(struct net *net, 6064 const struct sctp_endpoint *ep, 6065 const struct sctp_association *asoc, 6066 const struct sctp_chunk *chunk, 6067 sctp_cmd_seq_t *commands, 6068 struct sctp_chunk *err_chunk) 6069 { 6070 struct sctp_packet *packet; 6071 6072 if (err_chunk) { 6073 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6074 if (packet) { 6075 struct sctp_signed_cookie *cookie; 6076 6077 /* Override the OOTB vtag from the cookie. */ 6078 cookie = chunk->subh.cookie_hdr; 6079 packet->vtag = cookie->c.peer_vtag; 6080 6081 /* Set the skb to the belonging sock for accounting. */ 6082 err_chunk->skb->sk = ep->base.sk; 6083 sctp_packet_append_chunk(packet, err_chunk); 6084 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6085 SCTP_PACKET(packet)); 6086 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6087 } else 6088 sctp_chunk_free (err_chunk); 6089 } 6090 } 6091 6092 6093 /* Process a data chunk */ 6094 static int sctp_eat_data(const struct sctp_association *asoc, 6095 struct sctp_chunk *chunk, 6096 sctp_cmd_seq_t *commands) 6097 { 6098 sctp_datahdr_t *data_hdr; 6099 struct sctp_chunk *err; 6100 size_t datalen; 6101 sctp_verb_t deliver; 6102 int tmp; 6103 __u32 tsn; 6104 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6105 struct sock *sk = asoc->base.sk; 6106 struct net *net = sock_net(sk); 6107 u16 ssn; 6108 u16 sid; 6109 u8 ordered = 0; 6110 6111 data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; 6112 skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); 6113 6114 tsn = ntohl(data_hdr->tsn); 6115 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6116 6117 /* ASSERT: Now skb->data is really the user data. */ 6118 6119 /* Process ECN based congestion. 6120 * 6121 * Since the chunk structure is reused for all chunks within 6122 * a packet, we use ecn_ce_done to track if we've already 6123 * done CE processing for this packet. 6124 * 6125 * We need to do ECN processing even if we plan to discard the 6126 * chunk later. 6127 */ 6128 6129 if (!chunk->ecn_ce_done) { 6130 struct sctp_af *af; 6131 chunk->ecn_ce_done = 1; 6132 6133 af = sctp_get_af_specific( 6134 ipver2af(ip_hdr(chunk->skb)->version)); 6135 6136 if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { 6137 /* Do real work as sideffect. */ 6138 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6139 SCTP_U32(tsn)); 6140 } 6141 } 6142 6143 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6144 if (tmp < 0) { 6145 /* The TSN is too high--silently discard the chunk and 6146 * count on it getting retransmitted later. 6147 */ 6148 if (chunk->asoc) 6149 chunk->asoc->stats.outofseqtsns++; 6150 return SCTP_IERROR_HIGH_TSN; 6151 } else if (tmp > 0) { 6152 /* This is a duplicate. Record it. */ 6153 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6154 return SCTP_IERROR_DUP_TSN; 6155 } 6156 6157 /* This is a new TSN. */ 6158 6159 /* Discard if there is no room in the receive window. 6160 * Actually, allow a little bit of overflow (up to a MTU). 6161 */ 6162 datalen = ntohs(chunk->chunk_hdr->length); 6163 datalen -= sizeof(sctp_data_chunk_t); 6164 6165 deliver = SCTP_CMD_CHUNK_ULP; 6166 6167 /* Think about partial delivery. */ 6168 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6169 6170 /* Even if we don't accept this chunk there is 6171 * memory pressure. 6172 */ 6173 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6174 } 6175 6176 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6177 * seems a bit troublesome in that frag_point varies based on 6178 * PMTU. In cases, such as loopback, this might be a rather 6179 * large spill over. 6180 */ 6181 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6182 (datalen > asoc->rwnd + asoc->frag_point))) { 6183 6184 /* If this is the next TSN, consider reneging to make 6185 * room. Note: Playing nice with a confused sender. A 6186 * malicious sender can still eat up all our buffer 6187 * space and in the future we may want to detect and 6188 * do more drastic reneging. 6189 */ 6190 if (sctp_tsnmap_has_gap(map) && 6191 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6192 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6193 deliver = SCTP_CMD_RENEGE; 6194 } else { 6195 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6196 __func__, tsn, datalen, asoc->rwnd); 6197 6198 return SCTP_IERROR_IGNORE_TSN; 6199 } 6200 } 6201 6202 /* 6203 * Also try to renege to limit our memory usage in the event that 6204 * we are under memory pressure 6205 * If we can't renege, don't worry about it, the sk_rmem_schedule 6206 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6207 * memory usage too much 6208 */ 6209 if (*sk->sk_prot_creator->memory_pressure) { 6210 if (sctp_tsnmap_has_gap(map) && 6211 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6212 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6213 __func__, tsn); 6214 deliver = SCTP_CMD_RENEGE; 6215 } 6216 } 6217 6218 /* 6219 * Section 3.3.10.9 No User Data (9) 6220 * 6221 * Cause of error 6222 * --------------- 6223 * No User Data: This error cause is returned to the originator of a 6224 * DATA chunk if a received DATA chunk has no user data. 6225 */ 6226 if (unlikely(0 == datalen)) { 6227 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6228 if (err) { 6229 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6230 SCTP_CHUNK(err)); 6231 } 6232 /* We are going to ABORT, so we might as well stop 6233 * processing the rest of the chunks in the packet. 6234 */ 6235 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); 6236 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6237 SCTP_ERROR(ECONNABORTED)); 6238 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6239 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6240 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6241 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6242 return SCTP_IERROR_NO_DATA; 6243 } 6244 6245 chunk->data_accepted = 1; 6246 6247 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6248 * if we renege and the chunk arrives again. 6249 */ 6250 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6251 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6252 if (chunk->asoc) 6253 chunk->asoc->stats.iuodchunks++; 6254 } else { 6255 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6256 if (chunk->asoc) 6257 chunk->asoc->stats.iodchunks++; 6258 ordered = 1; 6259 } 6260 6261 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6262 * 6263 * If an endpoint receive a DATA chunk with an invalid stream 6264 * identifier, it shall acknowledge the reception of the DATA chunk 6265 * following the normal procedure, immediately send an ERROR chunk 6266 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6267 * and discard the DATA chunk. 6268 */ 6269 sid = ntohs(data_hdr->stream); 6270 if (sid >= asoc->c.sinit_max_instreams) { 6271 /* Mark tsn as received even though we drop it */ 6272 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6273 6274 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6275 &data_hdr->stream, 6276 sizeof(data_hdr->stream), 6277 sizeof(u16)); 6278 if (err) 6279 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6280 SCTP_CHUNK(err)); 6281 return SCTP_IERROR_BAD_STREAM; 6282 } 6283 6284 /* Check to see if the SSN is possible for this TSN. 6285 * The biggest gap we can record is 4K wide. Since SSNs wrap 6286 * at an unsigned short, there is no way that an SSN can 6287 * wrap and for a valid TSN. We can simply check if the current 6288 * SSN is smaller then the next expected one. If it is, it wrapped 6289 * and is invalid. 6290 */ 6291 ssn = ntohs(data_hdr->ssn); 6292 if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) { 6293 return SCTP_IERROR_PROTO_VIOLATION; 6294 } 6295 6296 /* Send the data up to the user. Note: Schedule the 6297 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6298 * chunk needs the updated rwnd. 6299 */ 6300 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6301 6302 return SCTP_IERROR_NO_ERROR; 6303 } 6304