input.c revision 7115e632f90952454ab6426e0d2151327162a30f
1/* SCTP kernel implementation 2 * Copyright (c) 1999-2000 Cisco, Inc. 3 * Copyright (c) 1999-2001 Motorola, Inc. 4 * Copyright (c) 2001-2003 International Business Machines, Corp. 5 * Copyright (c) 2001 Intel Corp. 6 * Copyright (c) 2001 Nokia, Inc. 7 * Copyright (c) 2001 La Monte H.P. Yarroll 8 * 9 * This file is part of the SCTP kernel implementation 10 * 11 * These functions handle all input from the IP layer into SCTP. 12 * 13 * This SCTP implementation is free software; 14 * you can redistribute it and/or modify it under the terms of 15 * the GNU General Public License as published by 16 * the Free Software Foundation; either version 2, or (at your option) 17 * any later version. 18 * 19 * This SCTP implementation is distributed in the hope that it 20 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 21 * ************************ 22 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 23 * See the GNU General Public License for more details. 24 * 25 * You should have received a copy of the GNU General Public License 26 * along with GNU CC; see the file COPYING. If not, write to 27 * the Free Software Foundation, 59 Temple Place - Suite 330, 28 * Boston, MA 02111-1307, USA. 29 * 30 * Please send any bug reports or fixes you make to the 31 * email address(es): 32 * lksctp developers <lksctp-developers@lists.sourceforge.net> 33 * 34 * Or submit a bug report through the following website: 35 * http://www.sf.net/projects/lksctp 36 * 37 * Written or modified by: 38 * La Monte H.P. Yarroll <piggy@acm.org> 39 * Karl Knutson <karl@athena.chicago.il.us> 40 * Xingang Guo <xingang.guo@intel.com> 41 * Jon Grimm <jgrimm@us.ibm.com> 42 * Hui Huang <hui.huang@nokia.com> 43 * Daisy Chang <daisyc@us.ibm.com> 44 * Sridhar Samudrala <sri@us.ibm.com> 45 * Ardelle Fan <ardelle.fan@intel.com> 46 * 47 * Any bugs reported given to us we will try to fix... any fixes shared will 48 * be incorporated into the next SCTP release. 49 */ 50 51#include <linux/types.h> 52#include <linux/list.h> /* For struct list_head */ 53#include <linux/socket.h> 54#include <linux/ip.h> 55#include <linux/time.h> /* For struct timeval */ 56#include <net/ip.h> 57#include <net/icmp.h> 58#include <net/snmp.h> 59#include <net/sock.h> 60#include <net/xfrm.h> 61#include <net/sctp/sctp.h> 62#include <net/sctp/sm.h> 63#include <net/sctp/checksum.h> 64 65/* Forward declarations for internal helpers. */ 66static int sctp_rcv_ootb(struct sk_buff *); 67static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, 68 const union sctp_addr *laddr, 69 const union sctp_addr *paddr, 70 struct sctp_transport **transportp); 71static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr); 72static struct sctp_association *__sctp_lookup_association( 73 const union sctp_addr *local, 74 const union sctp_addr *peer, 75 struct sctp_transport **pt); 76 77static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb); 78 79 80/* Calculate the SCTP checksum of an SCTP packet. */ 81static inline int sctp_rcv_checksum(struct sk_buff *skb) 82{ 83 struct sk_buff *list = skb_shinfo(skb)->frag_list; 84 struct sctphdr *sh = sctp_hdr(skb); 85 __u32 cmp = ntohl(sh->checksum); 86 __u32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); 87 88 for (; list; list = list->next) 89 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), 90 val); 91 92 val = sctp_end_cksum(val); 93 94 if (val != cmp) { 95 /* CRC failure, dump it. */ 96 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS); 97 return -1; 98 } 99 return 0; 100} 101 102struct sctp_input_cb { 103 union { 104 struct inet_skb_parm h4; 105#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 106 struct inet6_skb_parm h6; 107#endif 108 } header; 109 struct sctp_chunk *chunk; 110}; 111#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) 112 113/* 114 * This is the routine which IP calls when receiving an SCTP packet. 115 */ 116int sctp_rcv(struct sk_buff *skb) 117{ 118 struct sock *sk; 119 struct sctp_association *asoc; 120 struct sctp_endpoint *ep = NULL; 121 struct sctp_ep_common *rcvr; 122 struct sctp_transport *transport = NULL; 123 struct sctp_chunk *chunk; 124 struct sctphdr *sh; 125 union sctp_addr src; 126 union sctp_addr dest; 127 int family; 128 struct sctp_af *af; 129 130 if (skb->pkt_type!=PACKET_HOST) 131 goto discard_it; 132 133 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); 134 135 if (skb_linearize(skb)) 136 goto discard_it; 137 138 sh = sctp_hdr(skb); 139 140 /* Pull up the IP and SCTP headers. */ 141 __skb_pull(skb, skb_transport_offset(skb)); 142 if (skb->len < sizeof(struct sctphdr)) 143 goto discard_it; 144 if (!skb_csum_unnecessary(skb) && sctp_rcv_checksum(skb) < 0) 145 goto discard_it; 146 147 skb_pull(skb, sizeof(struct sctphdr)); 148 149 /* Make sure we at least have chunk headers worth of data left. */ 150 if (skb->len < sizeof(struct sctp_chunkhdr)) 151 goto discard_it; 152 153 family = ipver2af(ip_hdr(skb)->version); 154 af = sctp_get_af_specific(family); 155 if (unlikely(!af)) 156 goto discard_it; 157 158 /* Initialize local addresses for lookups. */ 159 af->from_skb(&src, skb, 1); 160 af->from_skb(&dest, skb, 0); 161 162 /* If the packet is to or from a non-unicast address, 163 * silently discard the packet. 164 * 165 * This is not clearly defined in the RFC except in section 166 * 8.4 - OOTB handling. However, based on the book "Stream Control 167 * Transmission Protocol" 2.1, "It is important to note that the 168 * IP address of an SCTP transport address must be a routable 169 * unicast address. In other words, IP multicast addresses and 170 * IP broadcast addresses cannot be used in an SCTP transport 171 * address." 172 */ 173 if (!af->addr_valid(&src, NULL, skb) || 174 !af->addr_valid(&dest, NULL, skb)) 175 goto discard_it; 176 177 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); 178 179 if (!asoc) 180 ep = __sctp_rcv_lookup_endpoint(&dest); 181 182 /* Retrieve the common input handling substructure. */ 183 rcvr = asoc ? &asoc->base : &ep->base; 184 sk = rcvr->sk; 185 186 /* 187 * If a frame arrives on an interface and the receiving socket is 188 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB 189 */ 190 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) 191 { 192 if (asoc) { 193 sctp_association_put(asoc); 194 asoc = NULL; 195 } else { 196 sctp_endpoint_put(ep); 197 ep = NULL; 198 } 199 sk = sctp_get_ctl_sock(); 200 ep = sctp_sk(sk)->ep; 201 sctp_endpoint_hold(ep); 202 rcvr = &ep->base; 203 } 204 205 /* 206 * RFC 2960, 8.4 - Handle "Out of the blue" Packets. 207 * An SCTP packet is called an "out of the blue" (OOTB) 208 * packet if it is correctly formed, i.e., passed the 209 * receiver's checksum check, but the receiver is not 210 * able to identify the association to which this 211 * packet belongs. 212 */ 213 if (!asoc) { 214 if (sctp_rcv_ootb(skb)) { 215 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES); 216 goto discard_release; 217 } 218 } 219 220 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) 221 goto discard_release; 222 nf_reset(skb); 223 224 if (sk_filter(sk, skb)) 225 goto discard_release; 226 227 /* Create an SCTP packet structure. */ 228 chunk = sctp_chunkify(skb, asoc, sk); 229 if (!chunk) 230 goto discard_release; 231 SCTP_INPUT_CB(skb)->chunk = chunk; 232 233 /* Remember what endpoint is to handle this packet. */ 234 chunk->rcvr = rcvr; 235 236 /* Remember the SCTP header. */ 237 chunk->sctp_hdr = sh; 238 239 /* Set the source and destination addresses of the incoming chunk. */ 240 sctp_init_addrs(chunk, &src, &dest); 241 242 /* Remember where we came from. */ 243 chunk->transport = transport; 244 245 /* Acquire access to the sock lock. Note: We are safe from other 246 * bottom halves on this lock, but a user may be in the lock too, 247 * so check if it is busy. 248 */ 249 sctp_bh_lock_sock(sk); 250 251 if (sock_owned_by_user(sk)) { 252 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG); 253 sctp_add_backlog(sk, skb); 254 } else { 255 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ); 256 sctp_inq_push(&chunk->rcvr->inqueue, chunk); 257 } 258 259 sctp_bh_unlock_sock(sk); 260 261 /* Release the asoc/ep ref we took in the lookup calls. */ 262 if (asoc) 263 sctp_association_put(asoc); 264 else 265 sctp_endpoint_put(ep); 266 267 return 0; 268 269discard_it: 270 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS); 271 kfree_skb(skb); 272 return 0; 273 274discard_release: 275 /* Release the asoc/ep ref we took in the lookup calls. */ 276 if (asoc) 277 sctp_association_put(asoc); 278 else 279 sctp_endpoint_put(ep); 280 281 goto discard_it; 282} 283 284/* Process the backlog queue of the socket. Every skb on 285 * the backlog holds a ref on an association or endpoint. 286 * We hold this ref throughout the state machine to make 287 * sure that the structure we need is still around. 288 */ 289int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) 290{ 291 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; 292 struct sctp_inq *inqueue = &chunk->rcvr->inqueue; 293 struct sctp_ep_common *rcvr = NULL; 294 int backloged = 0; 295 296 rcvr = chunk->rcvr; 297 298 /* If the rcvr is dead then the association or endpoint 299 * has been deleted and we can safely drop the chunk 300 * and refs that we are holding. 301 */ 302 if (rcvr->dead) { 303 sctp_chunk_free(chunk); 304 goto done; 305 } 306 307 if (unlikely(rcvr->sk != sk)) { 308 /* In this case, the association moved from one socket to 309 * another. We are currently sitting on the backlog of the 310 * old socket, so we need to move. 311 * However, since we are here in the process context we 312 * need to take make sure that the user doesn't own 313 * the new socket when we process the packet. 314 * If the new socket is user-owned, queue the chunk to the 315 * backlog of the new socket without dropping any refs. 316 * Otherwise, we can safely push the chunk on the inqueue. 317 */ 318 319 sk = rcvr->sk; 320 sctp_bh_lock_sock(sk); 321 322 if (sock_owned_by_user(sk)) { 323 sk_add_backlog(sk, skb); 324 backloged = 1; 325 } else 326 sctp_inq_push(inqueue, chunk); 327 328 sctp_bh_unlock_sock(sk); 329 330 /* If the chunk was backloged again, don't drop refs */ 331 if (backloged) 332 return 0; 333 } else { 334 sctp_inq_push(inqueue, chunk); 335 } 336 337done: 338 /* Release the refs we took in sctp_add_backlog */ 339 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) 340 sctp_association_put(sctp_assoc(rcvr)); 341 else if (SCTP_EP_TYPE_SOCKET == rcvr->type) 342 sctp_endpoint_put(sctp_ep(rcvr)); 343 else 344 BUG(); 345 346 return 0; 347} 348 349static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb) 350{ 351 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; 352 struct sctp_ep_common *rcvr = chunk->rcvr; 353 354 /* Hold the assoc/ep while hanging on the backlog queue. 355 * This way, we know structures we need will not disappear from us 356 */ 357 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) 358 sctp_association_hold(sctp_assoc(rcvr)); 359 else if (SCTP_EP_TYPE_SOCKET == rcvr->type) 360 sctp_endpoint_hold(sctp_ep(rcvr)); 361 else 362 BUG(); 363 364 sk_add_backlog(sk, skb); 365} 366 367/* Handle icmp frag needed error. */ 368void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, 369 struct sctp_transport *t, __u32 pmtu) 370{ 371 if (!t || (t->pathmtu == pmtu)) 372 return; 373 374 if (sock_owned_by_user(sk)) { 375 asoc->pmtu_pending = 1; 376 t->pmtu_pending = 1; 377 return; 378 } 379 380 if (t->param_flags & SPP_PMTUD_ENABLE) { 381 /* Update transports view of the MTU */ 382 sctp_transport_update_pmtu(t, pmtu); 383 384 /* Update association pmtu. */ 385 sctp_assoc_sync_pmtu(asoc); 386 } 387 388 /* Retransmit with the new pmtu setting. 389 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation 390 * Needed will never be sent, but if a message was sent before 391 * PMTU discovery was disabled that was larger than the PMTU, it 392 * would not be fragmented, so it must be re-transmitted fragmented. 393 */ 394 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); 395} 396 397/* 398 * SCTP Implementer's Guide, 2.37 ICMP handling procedures 399 * 400 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" 401 * or a "Protocol Unreachable" treat this message as an abort 402 * with the T bit set. 403 * 404 * This function sends an event to the state machine, which will abort the 405 * association. 406 * 407 */ 408void sctp_icmp_proto_unreachable(struct sock *sk, 409 struct sctp_association *asoc, 410 struct sctp_transport *t) 411{ 412 SCTP_DEBUG_PRINTK("%s\n", __func__); 413 414 sctp_do_sm(SCTP_EVENT_T_OTHER, 415 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), 416 asoc->state, asoc->ep, asoc, t, 417 GFP_ATOMIC); 418 419} 420 421/* Common lookup code for icmp/icmpv6 error handler. */ 422struct sock *sctp_err_lookup(int family, struct sk_buff *skb, 423 struct sctphdr *sctphdr, 424 struct sctp_association **app, 425 struct sctp_transport **tpp) 426{ 427 union sctp_addr saddr; 428 union sctp_addr daddr; 429 struct sctp_af *af; 430 struct sock *sk = NULL; 431 struct sctp_association *asoc; 432 struct sctp_transport *transport = NULL; 433 struct sctp_init_chunk *chunkhdr; 434 __u32 vtag = ntohl(sctphdr->vtag); 435 int len = skb->len - ((void *)sctphdr - (void *)skb->data); 436 437 *app = NULL; *tpp = NULL; 438 439 af = sctp_get_af_specific(family); 440 if (unlikely(!af)) { 441 return NULL; 442 } 443 444 /* Initialize local addresses for lookups. */ 445 af->from_skb(&saddr, skb, 1); 446 af->from_skb(&daddr, skb, 0); 447 448 /* Look for an association that matches the incoming ICMP error 449 * packet. 450 */ 451 asoc = __sctp_lookup_association(&saddr, &daddr, &transport); 452 if (!asoc) 453 return NULL; 454 455 sk = asoc->base.sk; 456 457 /* RFC 4960, Appendix C. ICMP Handling 458 * 459 * ICMP6) An implementation MUST validate that the Verification Tag 460 * contained in the ICMP message matches the Verification Tag of 461 * the peer. If the Verification Tag is not 0 and does NOT 462 * match, discard the ICMP message. If it is 0 and the ICMP 463 * message contains enough bytes to verify that the chunk type is 464 * an INIT chunk and that the Initiate Tag matches the tag of the 465 * peer, continue with ICMP7. If the ICMP message is too short 466 * or the chunk type or the Initiate Tag does not match, silently 467 * discard the packet. 468 */ 469 if (vtag == 0) { 470 chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr 471 + sizeof(struct sctphdr)); 472 if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t) 473 + sizeof(__be32) || 474 chunkhdr->chunk_hdr.type != SCTP_CID_INIT || 475 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) { 476 goto out; 477 } 478 } else if (vtag != asoc->c.peer_vtag) { 479 goto out; 480 } 481 482 sctp_bh_lock_sock(sk); 483 484 /* If too many ICMPs get dropped on busy 485 * servers this needs to be solved differently. 486 */ 487 if (sock_owned_by_user(sk)) 488 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); 489 490 *app = asoc; 491 *tpp = transport; 492 return sk; 493 494out: 495 if (asoc) 496 sctp_association_put(asoc); 497 return NULL; 498} 499 500/* Common cleanup code for icmp/icmpv6 error handler. */ 501void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) 502{ 503 sctp_bh_unlock_sock(sk); 504 if (asoc) 505 sctp_association_put(asoc); 506} 507 508/* 509 * This routine is called by the ICMP module when it gets some 510 * sort of error condition. If err < 0 then the socket should 511 * be closed and the error returned to the user. If err > 0 512 * it's just the icmp type << 8 | icmp code. After adjustment 513 * header points to the first 8 bytes of the sctp header. We need 514 * to find the appropriate port. 515 * 516 * The locking strategy used here is very "optimistic". When 517 * someone else accesses the socket the ICMP is just dropped 518 * and for some paths there is no check at all. 519 * A more general error queue to queue errors for later handling 520 * is probably better. 521 * 522 */ 523void sctp_v4_err(struct sk_buff *skb, __u32 info) 524{ 525 struct iphdr *iph = (struct iphdr *)skb->data; 526 const int ihlen = iph->ihl * 4; 527 const int type = icmp_hdr(skb)->type; 528 const int code = icmp_hdr(skb)->code; 529 struct sock *sk; 530 struct sctp_association *asoc = NULL; 531 struct sctp_transport *transport; 532 struct inet_sock *inet; 533 sk_buff_data_t saveip, savesctp; 534 int err; 535 536 if (skb->len < ihlen + 8) { 537 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 538 return; 539 } 540 541 /* Fix up skb to look at the embedded net header. */ 542 saveip = skb->network_header; 543 savesctp = skb->transport_header; 544 skb_reset_network_header(skb); 545 skb_set_transport_header(skb, ihlen); 546 sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport); 547 /* Put back, the original values. */ 548 skb->network_header = saveip; 549 skb->transport_header = savesctp; 550 if (!sk) { 551 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 552 return; 553 } 554 /* Warning: The sock lock is held. Remember to call 555 * sctp_err_finish! 556 */ 557 558 switch (type) { 559 case ICMP_PARAMETERPROB: 560 err = EPROTO; 561 break; 562 case ICMP_DEST_UNREACH: 563 if (code > NR_ICMP_UNREACH) 564 goto out_unlock; 565 566 /* PMTU discovery (RFC1191) */ 567 if (ICMP_FRAG_NEEDED == code) { 568 sctp_icmp_frag_needed(sk, asoc, transport, info); 569 goto out_unlock; 570 } 571 else { 572 if (ICMP_PROT_UNREACH == code) { 573 sctp_icmp_proto_unreachable(sk, asoc, 574 transport); 575 goto out_unlock; 576 } 577 } 578 err = icmp_err_convert[code].errno; 579 break; 580 case ICMP_TIME_EXCEEDED: 581 /* Ignore any time exceeded errors due to fragment reassembly 582 * timeouts. 583 */ 584 if (ICMP_EXC_FRAGTIME == code) 585 goto out_unlock; 586 587 err = EHOSTUNREACH; 588 break; 589 default: 590 goto out_unlock; 591 } 592 593 inet = inet_sk(sk); 594 if (!sock_owned_by_user(sk) && inet->recverr) { 595 sk->sk_err = err; 596 sk->sk_error_report(sk); 597 } else { /* Only an error on timeout */ 598 sk->sk_err_soft = err; 599 } 600 601out_unlock: 602 sctp_err_finish(sk, asoc); 603} 604 605/* 606 * RFC 2960, 8.4 - Handle "Out of the blue" Packets. 607 * 608 * This function scans all the chunks in the OOTB packet to determine if 609 * the packet should be discarded right away. If a response might be needed 610 * for this packet, or, if further processing is possible, the packet will 611 * be queued to a proper inqueue for the next phase of handling. 612 * 613 * Output: 614 * Return 0 - If further processing is needed. 615 * Return 1 - If the packet can be discarded right away. 616 */ 617static int sctp_rcv_ootb(struct sk_buff *skb) 618{ 619 sctp_chunkhdr_t *ch; 620 __u8 *ch_end; 621 sctp_errhdr_t *err; 622 623 ch = (sctp_chunkhdr_t *) skb->data; 624 625 /* Scan through all the chunks in the packet. */ 626 do { 627 /* Break out if chunk length is less then minimal. */ 628 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 629 break; 630 631 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 632 if (ch_end > skb_tail_pointer(skb)) 633 break; 634 635 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the 636 * receiver MUST silently discard the OOTB packet and take no 637 * further action. 638 */ 639 if (SCTP_CID_ABORT == ch->type) 640 goto discard; 641 642 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE 643 * chunk, the receiver should silently discard the packet 644 * and take no further action. 645 */ 646 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) 647 goto discard; 648 649 /* RFC 4460, 2.11.2 650 * This will discard packets with INIT chunk bundled as 651 * subsequent chunks in the packet. When INIT is first, 652 * the normal INIT processing will discard the chunk. 653 */ 654 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) 655 goto discard; 656 657 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 658 * or a COOKIE ACK the SCTP Packet should be silently 659 * discarded. 660 */ 661 if (SCTP_CID_COOKIE_ACK == ch->type) 662 goto discard; 663 664 if (SCTP_CID_ERROR == ch->type) { 665 sctp_walk_errors(err, ch) { 666 if (SCTP_ERROR_STALE_COOKIE == err->cause) 667 goto discard; 668 } 669 } 670 671 ch = (sctp_chunkhdr_t *) ch_end; 672 } while (ch_end < skb_tail_pointer(skb)); 673 674 return 0; 675 676discard: 677 return 1; 678} 679 680/* Insert endpoint into the hash table. */ 681static void __sctp_hash_endpoint(struct sctp_endpoint *ep) 682{ 683 struct sctp_ep_common *epb; 684 struct sctp_hashbucket *head; 685 686 epb = &ep->base; 687 688 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); 689 head = &sctp_ep_hashtable[epb->hashent]; 690 691 sctp_write_lock(&head->lock); 692 hlist_add_head(&epb->node, &head->chain); 693 sctp_write_unlock(&head->lock); 694} 695 696/* Add an endpoint to the hash. Local BH-safe. */ 697void sctp_hash_endpoint(struct sctp_endpoint *ep) 698{ 699 sctp_local_bh_disable(); 700 __sctp_hash_endpoint(ep); 701 sctp_local_bh_enable(); 702} 703 704/* Remove endpoint from the hash table. */ 705static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) 706{ 707 struct sctp_hashbucket *head; 708 struct sctp_ep_common *epb; 709 710 epb = &ep->base; 711 712 if (hlist_unhashed(&epb->node)) 713 return; 714 715 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); 716 717 head = &sctp_ep_hashtable[epb->hashent]; 718 719 sctp_write_lock(&head->lock); 720 __hlist_del(&epb->node); 721 sctp_write_unlock(&head->lock); 722} 723 724/* Remove endpoint from the hash. Local BH-safe. */ 725void sctp_unhash_endpoint(struct sctp_endpoint *ep) 726{ 727 sctp_local_bh_disable(); 728 __sctp_unhash_endpoint(ep); 729 sctp_local_bh_enable(); 730} 731 732/* Look up an endpoint. */ 733static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) 734{ 735 struct sctp_hashbucket *head; 736 struct sctp_ep_common *epb; 737 struct sctp_endpoint *ep; 738 struct hlist_node *node; 739 int hash; 740 741 hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port)); 742 head = &sctp_ep_hashtable[hash]; 743 read_lock(&head->lock); 744 sctp_for_each_hentry(epb, node, &head->chain) { 745 ep = sctp_ep(epb); 746 if (sctp_endpoint_is_match(ep, laddr)) 747 goto hit; 748 } 749 750 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 751 752hit: 753 sctp_endpoint_hold(ep); 754 read_unlock(&head->lock); 755 return ep; 756} 757 758/* Insert association into the hash table. */ 759static void __sctp_hash_established(struct sctp_association *asoc) 760{ 761 struct sctp_ep_common *epb; 762 struct sctp_hashbucket *head; 763 764 epb = &asoc->base; 765 766 /* Calculate which chain this entry will belong to. */ 767 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); 768 769 head = &sctp_assoc_hashtable[epb->hashent]; 770 771 sctp_write_lock(&head->lock); 772 hlist_add_head(&epb->node, &head->chain); 773 sctp_write_unlock(&head->lock); 774} 775 776/* Add an association to the hash. Local BH-safe. */ 777void sctp_hash_established(struct sctp_association *asoc) 778{ 779 if (asoc->temp) 780 return; 781 782 sctp_local_bh_disable(); 783 __sctp_hash_established(asoc); 784 sctp_local_bh_enable(); 785} 786 787/* Remove association from the hash table. */ 788static void __sctp_unhash_established(struct sctp_association *asoc) 789{ 790 struct sctp_hashbucket *head; 791 struct sctp_ep_common *epb; 792 793 epb = &asoc->base; 794 795 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, 796 asoc->peer.port); 797 798 head = &sctp_assoc_hashtable[epb->hashent]; 799 800 sctp_write_lock(&head->lock); 801 __hlist_del(&epb->node); 802 sctp_write_unlock(&head->lock); 803} 804 805/* Remove association from the hash table. Local BH-safe. */ 806void sctp_unhash_established(struct sctp_association *asoc) 807{ 808 if (asoc->temp) 809 return; 810 811 sctp_local_bh_disable(); 812 __sctp_unhash_established(asoc); 813 sctp_local_bh_enable(); 814} 815 816/* Look up an association. */ 817static struct sctp_association *__sctp_lookup_association( 818 const union sctp_addr *local, 819 const union sctp_addr *peer, 820 struct sctp_transport **pt) 821{ 822 struct sctp_hashbucket *head; 823 struct sctp_ep_common *epb; 824 struct sctp_association *asoc; 825 struct sctp_transport *transport; 826 struct hlist_node *node; 827 int hash; 828 829 /* Optimize here for direct hit, only listening connections can 830 * have wildcards anyways. 831 */ 832 hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port)); 833 head = &sctp_assoc_hashtable[hash]; 834 read_lock(&head->lock); 835 sctp_for_each_hentry(epb, node, &head->chain) { 836 asoc = sctp_assoc(epb); 837 transport = sctp_assoc_is_match(asoc, local, peer); 838 if (transport) 839 goto hit; 840 } 841 842 read_unlock(&head->lock); 843 844 return NULL; 845 846hit: 847 *pt = transport; 848 sctp_association_hold(asoc); 849 read_unlock(&head->lock); 850 return asoc; 851} 852 853/* Look up an association. BH-safe. */ 854SCTP_STATIC 855struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, 856 const union sctp_addr *paddr, 857 struct sctp_transport **transportp) 858{ 859 struct sctp_association *asoc; 860 861 sctp_local_bh_disable(); 862 asoc = __sctp_lookup_association(laddr, paddr, transportp); 863 sctp_local_bh_enable(); 864 865 return asoc; 866} 867 868/* Is there an association matching the given local and peer addresses? */ 869int sctp_has_association(const union sctp_addr *laddr, 870 const union sctp_addr *paddr) 871{ 872 struct sctp_association *asoc; 873 struct sctp_transport *transport; 874 875 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { 876 sctp_association_put(asoc); 877 return 1; 878 } 879 880 return 0; 881} 882 883/* 884 * SCTP Implementors Guide, 2.18 Handling of address 885 * parameters within the INIT or INIT-ACK. 886 * 887 * D) When searching for a matching TCB upon reception of an INIT 888 * or INIT-ACK chunk the receiver SHOULD use not only the 889 * source address of the packet (containing the INIT or 890 * INIT-ACK) but the receiver SHOULD also use all valid 891 * address parameters contained within the chunk. 892 * 893 * 2.18.3 Solution description 894 * 895 * This new text clearly specifies to an implementor the need 896 * to look within the INIT or INIT-ACK. Any implementation that 897 * does not do this, may not be able to establish associations 898 * in certain circumstances. 899 * 900 */ 901static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, 902 const union sctp_addr *laddr, struct sctp_transport **transportp) 903{ 904 struct sctp_association *asoc; 905 union sctp_addr addr; 906 union sctp_addr *paddr = &addr; 907 struct sctphdr *sh = sctp_hdr(skb); 908 sctp_chunkhdr_t *ch; 909 union sctp_params params; 910 sctp_init_chunk_t *init; 911 struct sctp_transport *transport; 912 struct sctp_af *af; 913 914 ch = (sctp_chunkhdr_t *) skb->data; 915 916 /* 917 * This code will NOT touch anything inside the chunk--it is 918 * strictly READ-ONLY. 919 * 920 * RFC 2960 3 SCTP packet Format 921 * 922 * Multiple chunks can be bundled into one SCTP packet up to 923 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN 924 * COMPLETE chunks. These chunks MUST NOT be bundled with any 925 * other chunk in a packet. See Section 6.10 for more details 926 * on chunk bundling. 927 */ 928 929 /* Find the start of the TLVs and the end of the chunk. This is 930 * the region we search for address parameters. 931 */ 932 init = (sctp_init_chunk_t *)skb->data; 933 934 /* Walk the parameters looking for embedded addresses. */ 935 sctp_walk_params(params, init, init_hdr.params) { 936 937 /* Note: Ignoring hostname addresses. */ 938 af = sctp_get_af_specific(param_type2af(params.p->type)); 939 if (!af) 940 continue; 941 942 af->from_addr_param(paddr, params.addr, sh->source, 0); 943 944 asoc = __sctp_lookup_association(laddr, paddr, &transport); 945 if (asoc) 946 return asoc; 947 } 948 949 return NULL; 950} 951 952/* ADD-IP, Section 5.2 953 * When an endpoint receives an ASCONF Chunk from the remote peer 954 * special procedures may be needed to identify the association the 955 * ASCONF Chunk is associated with. To properly find the association 956 * the following procedures SHOULD be followed: 957 * 958 * D2) If the association is not found, use the address found in the 959 * Address Parameter TLV combined with the port number found in the 960 * SCTP common header. If found proceed to rule D4. 961 * 962 * D2-ext) If more than one ASCONF Chunks are packed together, use the 963 * address found in the ASCONF Address Parameter TLV of each of the 964 * subsequent ASCONF Chunks. If found, proceed to rule D4. 965 */ 966static struct sctp_association *__sctp_rcv_asconf_lookup( 967 sctp_chunkhdr_t *ch, 968 const union sctp_addr *laddr, 969 __be16 peer_port, 970 struct sctp_transport **transportp) 971{ 972 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; 973 struct sctp_af *af; 974 union sctp_addr_param *param; 975 union sctp_addr paddr; 976 977 /* Skip over the ADDIP header and find the Address parameter */ 978 param = (union sctp_addr_param *)(asconf + 1); 979 980 af = sctp_get_af_specific(param_type2af(param->v4.param_hdr.type)); 981 if (unlikely(!af)) 982 return NULL; 983 984 af->from_addr_param(&paddr, param, peer_port, 0); 985 986 return __sctp_lookup_association(laddr, &paddr, transportp); 987} 988 989 990/* SCTP-AUTH, Section 6.3: 991* If the receiver does not find a STCB for a packet containing an AUTH 992* chunk as the first chunk and not a COOKIE-ECHO chunk as the second 993* chunk, it MUST use the chunks after the AUTH chunk to look up an existing 994* association. 995* 996* This means that any chunks that can help us identify the association need 997* to be looked at to find this assocation. 998*/ 999static struct sctp_association *__sctp_rcv_walk_lookup(struct sk_buff *skb, 1000 const union sctp_addr *laddr, 1001 struct sctp_transport **transportp) 1002{ 1003 struct sctp_association *asoc = NULL; 1004 sctp_chunkhdr_t *ch; 1005 int have_auth = 0; 1006 unsigned int chunk_num = 1; 1007 __u8 *ch_end; 1008 1009 /* Walk through the chunks looking for AUTH or ASCONF chunks 1010 * to help us find the association. 1011 */ 1012 ch = (sctp_chunkhdr_t *) skb->data; 1013 do { 1014 /* Break out if chunk length is less then minimal. */ 1015 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 1016 break; 1017 1018 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 1019 if (ch_end > skb_tail_pointer(skb)) 1020 break; 1021 1022 switch(ch->type) { 1023 case SCTP_CID_AUTH: 1024 have_auth = chunk_num; 1025 break; 1026 1027 case SCTP_CID_COOKIE_ECHO: 1028 /* If a packet arrives containing an AUTH chunk as 1029 * a first chunk, a COOKIE-ECHO chunk as the second 1030 * chunk, and possibly more chunks after them, and 1031 * the receiver does not have an STCB for that 1032 * packet, then authentication is based on 1033 * the contents of the COOKIE- ECHO chunk. 1034 */ 1035 if (have_auth == 1 && chunk_num == 2) 1036 return NULL; 1037 break; 1038 1039 case SCTP_CID_ASCONF: 1040 if (have_auth || sctp_addip_noauth) 1041 asoc = __sctp_rcv_asconf_lookup(ch, laddr, 1042 sctp_hdr(skb)->source, 1043 transportp); 1044 default: 1045 break; 1046 } 1047 1048 if (asoc) 1049 break; 1050 1051 ch = (sctp_chunkhdr_t *) ch_end; 1052 chunk_num++; 1053 } while (ch_end < skb_tail_pointer(skb)); 1054 1055 return asoc; 1056} 1057 1058/* 1059 * There are circumstances when we need to look inside the SCTP packet 1060 * for information to help us find the association. Examples 1061 * include looking inside of INIT/INIT-ACK chunks or after the AUTH 1062 * chunks. 1063 */ 1064static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb, 1065 const union sctp_addr *laddr, 1066 struct sctp_transport **transportp) 1067{ 1068 sctp_chunkhdr_t *ch; 1069 1070 ch = (sctp_chunkhdr_t *) skb->data; 1071 1072 /* The code below will attempt to walk the chunk and extract 1073 * parameter information. Before we do that, we need to verify 1074 * that the chunk length doesn't cause overflow. Otherwise, we'll 1075 * walk off the end. 1076 */ 1077 if (WORD_ROUND(ntohs(ch->length)) > skb->len) 1078 return NULL; 1079 1080 /* If this is INIT/INIT-ACK look inside the chunk too. */ 1081 switch (ch->type) { 1082 case SCTP_CID_INIT: 1083 case SCTP_CID_INIT_ACK: 1084 return __sctp_rcv_init_lookup(skb, laddr, transportp); 1085 break; 1086 1087 default: 1088 return __sctp_rcv_walk_lookup(skb, laddr, transportp); 1089 break; 1090 } 1091 1092 1093 return NULL; 1094} 1095 1096/* Lookup an association for an inbound skb. */ 1097static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, 1098 const union sctp_addr *paddr, 1099 const union sctp_addr *laddr, 1100 struct sctp_transport **transportp) 1101{ 1102 struct sctp_association *asoc; 1103 1104 asoc = __sctp_lookup_association(laddr, paddr, transportp); 1105 1106 /* Further lookup for INIT/INIT-ACK packets. 1107 * SCTP Implementors Guide, 2.18 Handling of address 1108 * parameters within the INIT or INIT-ACK. 1109 */ 1110 if (!asoc) 1111 asoc = __sctp_rcv_lookup_harder(skb, laddr, transportp); 1112 1113 return asoc; 1114} 1115