input.c revision a27ef749e7be3b06fb58df53d94eb97a21f18707
1/* SCTP kernel reference 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 reference Implementation 10 * 11 * These functions handle all input from the IP layer into SCTP. 12 * 13 * The SCTP reference 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 * The SCTP reference 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 64/* Forward declarations for internal helpers. */ 65static int sctp_rcv_ootb(struct sk_buff *); 66static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, 67 const union sctp_addr *laddr, 68 const union sctp_addr *paddr, 69 struct sctp_transport **transportp); 70static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr); 71static struct sctp_association *__sctp_lookup_association( 72 const union sctp_addr *local, 73 const union sctp_addr *peer, 74 struct sctp_transport **pt); 75 76static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb); 77 78 79/* Calculate the SCTP checksum of an SCTP packet. */ 80static inline int sctp_rcv_checksum(struct sk_buff *skb) 81{ 82 struct sk_buff *list = skb_shinfo(skb)->frag_list; 83 struct sctphdr *sh = sctp_hdr(skb); 84 __u32 cmp = ntohl(sh->checksum); 85 __u32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); 86 87 for (; list; list = list->next) 88 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), 89 val); 90 91 val = sctp_end_cksum(val); 92 93 if (val != cmp) { 94 /* CRC failure, dump it. */ 95 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS); 96 return -1; 97 } 98 return 0; 99} 100 101struct sctp_input_cb { 102 union { 103 struct inet_skb_parm h4; 104#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 105 struct inet6_skb_parm h6; 106#endif 107 } header; 108 struct sctp_chunk *chunk; 109}; 110#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) 111 112/* 113 * This is the routine which IP calls when receiving an SCTP packet. 114 */ 115int sctp_rcv(struct sk_buff *skb) 116{ 117 struct sock *sk; 118 struct sctp_association *asoc; 119 struct sctp_endpoint *ep = NULL; 120 struct sctp_ep_common *rcvr; 121 struct sctp_transport *transport = NULL; 122 struct sctp_chunk *chunk; 123 struct sctphdr *sh; 124 union sctp_addr src; 125 union sctp_addr dest; 126 int family; 127 struct sctp_af *af; 128 129 if (skb->pkt_type!=PACKET_HOST) 130 goto discard_it; 131 132 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); 133 134 if (skb_linearize(skb)) 135 goto discard_it; 136 137 sh = sctp_hdr(skb); 138 139 /* Pull up the IP and SCTP headers. */ 140 __skb_pull(skb, skb_transport_offset(skb)); 141 if (skb->len < sizeof(struct sctphdr)) 142 goto discard_it; 143 if ((skb->ip_summed != CHECKSUM_UNNECESSARY) && 144 (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 (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu)) 372 return; 373 374 if (t->param_flags & SPP_PMTUD_ENABLE) { 375 if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { 376 printk(KERN_WARNING "%s: Reported pmtu %d too low, " 377 "using default minimum of %d\n", 378 __FUNCTION__, pmtu, 379 SCTP_DEFAULT_MINSEGMENT); 380 /* Use default minimum segment size and disable 381 * pmtu discovery on this transport. 382 */ 383 t->pathmtu = SCTP_DEFAULT_MINSEGMENT; 384 t->param_flags = (t->param_flags & ~SPP_PMTUD) | 385 SPP_PMTUD_DISABLE; 386 } else { 387 t->pathmtu = pmtu; 388 } 389 390 /* Update association pmtu. */ 391 sctp_assoc_sync_pmtu(asoc); 392 } 393 394 /* Retransmit with the new pmtu setting. 395 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation 396 * Needed will never be sent, but if a message was sent before 397 * PMTU discovery was disabled that was larger than the PMTU, it 398 * would not be fragmented, so it must be re-transmitted fragmented. 399 */ 400 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); 401} 402 403/* 404 * SCTP Implementer's Guide, 2.37 ICMP handling procedures 405 * 406 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" 407 * or a "Protocol Unreachable" treat this message as an abort 408 * with the T bit set. 409 * 410 * This function sends an event to the state machine, which will abort the 411 * association. 412 * 413 */ 414void sctp_icmp_proto_unreachable(struct sock *sk, 415 struct sctp_association *asoc, 416 struct sctp_transport *t) 417{ 418 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__); 419 420 sctp_do_sm(SCTP_EVENT_T_OTHER, 421 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), 422 asoc->state, asoc->ep, asoc, t, 423 GFP_ATOMIC); 424 425} 426 427/* Common lookup code for icmp/icmpv6 error handler. */ 428struct sock *sctp_err_lookup(int family, struct sk_buff *skb, 429 struct sctphdr *sctphdr, 430 struct sctp_association **app, 431 struct sctp_transport **tpp) 432{ 433 union sctp_addr saddr; 434 union sctp_addr daddr; 435 struct sctp_af *af; 436 struct sock *sk = NULL; 437 struct sctp_association *asoc; 438 struct sctp_transport *transport = NULL; 439 440 *app = NULL; *tpp = NULL; 441 442 af = sctp_get_af_specific(family); 443 if (unlikely(!af)) { 444 return NULL; 445 } 446 447 /* Initialize local addresses for lookups. */ 448 af->from_skb(&saddr, skb, 1); 449 af->from_skb(&daddr, skb, 0); 450 451 /* Look for an association that matches the incoming ICMP error 452 * packet. 453 */ 454 asoc = __sctp_lookup_association(&saddr, &daddr, &transport); 455 if (!asoc) 456 return NULL; 457 458 sk = asoc->base.sk; 459 460 if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) { 461 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 462 goto out; 463 } 464 465 sctp_bh_lock_sock(sk); 466 467 /* If too many ICMPs get dropped on busy 468 * servers this needs to be solved differently. 469 */ 470 if (sock_owned_by_user(sk)) 471 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); 472 473 *app = asoc; 474 *tpp = transport; 475 return sk; 476 477out: 478 if (asoc) 479 sctp_association_put(asoc); 480 return NULL; 481} 482 483/* Common cleanup code for icmp/icmpv6 error handler. */ 484void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) 485{ 486 sctp_bh_unlock_sock(sk); 487 if (asoc) 488 sctp_association_put(asoc); 489} 490 491/* 492 * This routine is called by the ICMP module when it gets some 493 * sort of error condition. If err < 0 then the socket should 494 * be closed and the error returned to the user. If err > 0 495 * it's just the icmp type << 8 | icmp code. After adjustment 496 * header points to the first 8 bytes of the sctp header. We need 497 * to find the appropriate port. 498 * 499 * The locking strategy used here is very "optimistic". When 500 * someone else accesses the socket the ICMP is just dropped 501 * and for some paths there is no check at all. 502 * A more general error queue to queue errors for later handling 503 * is probably better. 504 * 505 */ 506void sctp_v4_err(struct sk_buff *skb, __u32 info) 507{ 508 struct iphdr *iph = (struct iphdr *)skb->data; 509 const int ihlen = iph->ihl * 4; 510 const int type = icmp_hdr(skb)->type; 511 const int code = icmp_hdr(skb)->code; 512 struct sock *sk; 513 struct sctp_association *asoc = NULL; 514 struct sctp_transport *transport; 515 struct inet_sock *inet; 516 char *saveip, *savesctp; 517 int err; 518 519 if (skb->len < ihlen + 8) { 520 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 521 return; 522 } 523 524 /* Fix up skb to look at the embedded net header. */ 525 saveip = skb->nh.raw; 526 savesctp = skb->h.raw; 527 skb_reset_network_header(skb); 528 skb_set_transport_header(skb, ihlen); 529 sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport); 530 /* Put back, the original pointers. */ 531 skb->nh.raw = saveip; 532 skb->h.raw = savesctp; 533 if (!sk) { 534 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); 535 return; 536 } 537 /* Warning: The sock lock is held. Remember to call 538 * sctp_err_finish! 539 */ 540 541 switch (type) { 542 case ICMP_PARAMETERPROB: 543 err = EPROTO; 544 break; 545 case ICMP_DEST_UNREACH: 546 if (code > NR_ICMP_UNREACH) 547 goto out_unlock; 548 549 /* PMTU discovery (RFC1191) */ 550 if (ICMP_FRAG_NEEDED == code) { 551 sctp_icmp_frag_needed(sk, asoc, transport, info); 552 goto out_unlock; 553 } 554 else { 555 if (ICMP_PROT_UNREACH == code) { 556 sctp_icmp_proto_unreachable(sk, asoc, 557 transport); 558 goto out_unlock; 559 } 560 } 561 err = icmp_err_convert[code].errno; 562 break; 563 case ICMP_TIME_EXCEEDED: 564 /* Ignore any time exceeded errors due to fragment reassembly 565 * timeouts. 566 */ 567 if (ICMP_EXC_FRAGTIME == code) 568 goto out_unlock; 569 570 err = EHOSTUNREACH; 571 break; 572 default: 573 goto out_unlock; 574 } 575 576 inet = inet_sk(sk); 577 if (!sock_owned_by_user(sk) && inet->recverr) { 578 sk->sk_err = err; 579 sk->sk_error_report(sk); 580 } else { /* Only an error on timeout */ 581 sk->sk_err_soft = err; 582 } 583 584out_unlock: 585 sctp_err_finish(sk, asoc); 586} 587 588/* 589 * RFC 2960, 8.4 - Handle "Out of the blue" Packets. 590 * 591 * This function scans all the chunks in the OOTB packet to determine if 592 * the packet should be discarded right away. If a response might be needed 593 * for this packet, or, if further processing is possible, the packet will 594 * be queued to a proper inqueue for the next phase of handling. 595 * 596 * Output: 597 * Return 0 - If further processing is needed. 598 * Return 1 - If the packet can be discarded right away. 599 */ 600int sctp_rcv_ootb(struct sk_buff *skb) 601{ 602 sctp_chunkhdr_t *ch; 603 __u8 *ch_end; 604 sctp_errhdr_t *err; 605 606 ch = (sctp_chunkhdr_t *) skb->data; 607 608 /* Scan through all the chunks in the packet. */ 609 do { 610 /* Break out if chunk length is less then minimal. */ 611 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) 612 break; 613 614 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 615 if (ch_end > skb->tail) 616 break; 617 618 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the 619 * receiver MUST silently discard the OOTB packet and take no 620 * further action. 621 */ 622 if (SCTP_CID_ABORT == ch->type) 623 goto discard; 624 625 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE 626 * chunk, the receiver should silently discard the packet 627 * and take no further action. 628 */ 629 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) 630 goto discard; 631 632 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 633 * or a COOKIE ACK the SCTP Packet should be silently 634 * discarded. 635 */ 636 if (SCTP_CID_COOKIE_ACK == ch->type) 637 goto discard; 638 639 if (SCTP_CID_ERROR == ch->type) { 640 sctp_walk_errors(err, ch) { 641 if (SCTP_ERROR_STALE_COOKIE == err->cause) 642 goto discard; 643 } 644 } 645 646 ch = (sctp_chunkhdr_t *) ch_end; 647 } while (ch_end < skb->tail); 648 649 return 0; 650 651discard: 652 return 1; 653} 654 655/* Insert endpoint into the hash table. */ 656static void __sctp_hash_endpoint(struct sctp_endpoint *ep) 657{ 658 struct sctp_ep_common **epp; 659 struct sctp_ep_common *epb; 660 struct sctp_hashbucket *head; 661 662 epb = &ep->base; 663 664 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); 665 head = &sctp_ep_hashtable[epb->hashent]; 666 667 sctp_write_lock(&head->lock); 668 epp = &head->chain; 669 epb->next = *epp; 670 if (epb->next) 671 (*epp)->pprev = &epb->next; 672 *epp = epb; 673 epb->pprev = epp; 674 sctp_write_unlock(&head->lock); 675} 676 677/* Add an endpoint to the hash. Local BH-safe. */ 678void sctp_hash_endpoint(struct sctp_endpoint *ep) 679{ 680 sctp_local_bh_disable(); 681 __sctp_hash_endpoint(ep); 682 sctp_local_bh_enable(); 683} 684 685/* Remove endpoint from the hash table. */ 686static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) 687{ 688 struct sctp_hashbucket *head; 689 struct sctp_ep_common *epb; 690 691 epb = &ep->base; 692 693 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); 694 695 head = &sctp_ep_hashtable[epb->hashent]; 696 697 sctp_write_lock(&head->lock); 698 699 if (epb->pprev) { 700 if (epb->next) 701 epb->next->pprev = epb->pprev; 702 *epb->pprev = epb->next; 703 epb->pprev = NULL; 704 } 705 706 sctp_write_unlock(&head->lock); 707} 708 709/* Remove endpoint from the hash. Local BH-safe. */ 710void sctp_unhash_endpoint(struct sctp_endpoint *ep) 711{ 712 sctp_local_bh_disable(); 713 __sctp_unhash_endpoint(ep); 714 sctp_local_bh_enable(); 715} 716 717/* Look up an endpoint. */ 718static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) 719{ 720 struct sctp_hashbucket *head; 721 struct sctp_ep_common *epb; 722 struct sctp_endpoint *ep; 723 int hash; 724 725 hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port)); 726 head = &sctp_ep_hashtable[hash]; 727 read_lock(&head->lock); 728 for (epb = head->chain; epb; epb = epb->next) { 729 ep = sctp_ep(epb); 730 if (sctp_endpoint_is_match(ep, laddr)) 731 goto hit; 732 } 733 734 ep = sctp_sk((sctp_get_ctl_sock()))->ep; 735 epb = &ep->base; 736 737hit: 738 sctp_endpoint_hold(ep); 739 read_unlock(&head->lock); 740 return ep; 741} 742 743/* Insert association into the hash table. */ 744static void __sctp_hash_established(struct sctp_association *asoc) 745{ 746 struct sctp_ep_common **epp; 747 struct sctp_ep_common *epb; 748 struct sctp_hashbucket *head; 749 750 epb = &asoc->base; 751 752 /* Calculate which chain this entry will belong to. */ 753 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); 754 755 head = &sctp_assoc_hashtable[epb->hashent]; 756 757 sctp_write_lock(&head->lock); 758 epp = &head->chain; 759 epb->next = *epp; 760 if (epb->next) 761 (*epp)->pprev = &epb->next; 762 *epp = epb; 763 epb->pprev = epp; 764 sctp_write_unlock(&head->lock); 765} 766 767/* Add an association to the hash. Local BH-safe. */ 768void sctp_hash_established(struct sctp_association *asoc) 769{ 770 if (asoc->temp) 771 return; 772 773 sctp_local_bh_disable(); 774 __sctp_hash_established(asoc); 775 sctp_local_bh_enable(); 776} 777 778/* Remove association from the hash table. */ 779static void __sctp_unhash_established(struct sctp_association *asoc) 780{ 781 struct sctp_hashbucket *head; 782 struct sctp_ep_common *epb; 783 784 epb = &asoc->base; 785 786 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, 787 asoc->peer.port); 788 789 head = &sctp_assoc_hashtable[epb->hashent]; 790 791 sctp_write_lock(&head->lock); 792 793 if (epb->pprev) { 794 if (epb->next) 795 epb->next->pprev = epb->pprev; 796 *epb->pprev = epb->next; 797 epb->pprev = NULL; 798 } 799 800 sctp_write_unlock(&head->lock); 801} 802 803/* Remove association from the hash table. Local BH-safe. */ 804void sctp_unhash_established(struct sctp_association *asoc) 805{ 806 if (asoc->temp) 807 return; 808 809 sctp_local_bh_disable(); 810 __sctp_unhash_established(asoc); 811 sctp_local_bh_enable(); 812} 813 814/* Look up an association. */ 815static struct sctp_association *__sctp_lookup_association( 816 const union sctp_addr *local, 817 const union sctp_addr *peer, 818 struct sctp_transport **pt) 819{ 820 struct sctp_hashbucket *head; 821 struct sctp_ep_common *epb; 822 struct sctp_association *asoc; 823 struct sctp_transport *transport; 824 int hash; 825 826 /* Optimize here for direct hit, only listening connections can 827 * have wildcards anyways. 828 */ 829 hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port)); 830 head = &sctp_assoc_hashtable[hash]; 831 read_lock(&head->lock); 832 for (epb = head->chain; epb; epb = epb->next) { 833 asoc = sctp_assoc(epb); 834 transport = sctp_assoc_is_match(asoc, local, peer); 835 if (transport) 836 goto hit; 837 } 838 839 read_unlock(&head->lock); 840 841 return NULL; 842 843hit: 844 *pt = transport; 845 sctp_association_hold(asoc); 846 read_unlock(&head->lock); 847 return asoc; 848} 849 850/* Look up an association. BH-safe. */ 851SCTP_STATIC 852struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, 853 const union sctp_addr *paddr, 854 struct sctp_transport **transportp) 855{ 856 struct sctp_association *asoc; 857 858 sctp_local_bh_disable(); 859 asoc = __sctp_lookup_association(laddr, paddr, transportp); 860 sctp_local_bh_enable(); 861 862 return asoc; 863} 864 865/* Is there an association matching the given local and peer addresses? */ 866int sctp_has_association(const union sctp_addr *laddr, 867 const union sctp_addr *paddr) 868{ 869 struct sctp_association *asoc; 870 struct sctp_transport *transport; 871 872 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { 873 sctp_association_put(asoc); 874 return 1; 875 } 876 877 return 0; 878} 879 880/* 881 * SCTP Implementors Guide, 2.18 Handling of address 882 * parameters within the INIT or INIT-ACK. 883 * 884 * D) When searching for a matching TCB upon reception of an INIT 885 * or INIT-ACK chunk the receiver SHOULD use not only the 886 * source address of the packet (containing the INIT or 887 * INIT-ACK) but the receiver SHOULD also use all valid 888 * address parameters contained within the chunk. 889 * 890 * 2.18.3 Solution description 891 * 892 * This new text clearly specifies to an implementor the need 893 * to look within the INIT or INIT-ACK. Any implementation that 894 * does not do this, may not be able to establish associations 895 * in certain circumstances. 896 * 897 */ 898static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, 899 const union sctp_addr *laddr, struct sctp_transport **transportp) 900{ 901 struct sctp_association *asoc; 902 union sctp_addr addr; 903 union sctp_addr *paddr = &addr; 904 struct sctphdr *sh = sctp_hdr(skb); 905 sctp_chunkhdr_t *ch; 906 union sctp_params params; 907 sctp_init_chunk_t *init; 908 struct sctp_transport *transport; 909 struct sctp_af *af; 910 911 ch = (sctp_chunkhdr_t *) skb->data; 912 913 /* If this is INIT/INIT-ACK look inside the chunk too. */ 914 switch (ch->type) { 915 case SCTP_CID_INIT: 916 case SCTP_CID_INIT_ACK: 917 break; 918 default: 919 return NULL; 920 } 921 922 /* The code below will attempt to walk the chunk and extract 923 * parameter information. Before we do that, we need to verify 924 * that the chunk length doesn't cause overflow. Otherwise, we'll 925 * walk off the end. 926 */ 927 if (WORD_ROUND(ntohs(ch->length)) > skb->len) 928 return NULL; 929 930 /* 931 * This code will NOT touch anything inside the chunk--it is 932 * strictly READ-ONLY. 933 * 934 * RFC 2960 3 SCTP packet Format 935 * 936 * Multiple chunks can be bundled into one SCTP packet up to 937 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN 938 * COMPLETE chunks. These chunks MUST NOT be bundled with any 939 * other chunk in a packet. See Section 6.10 for more details 940 * on chunk bundling. 941 */ 942 943 /* Find the start of the TLVs and the end of the chunk. This is 944 * the region we search for address parameters. 945 */ 946 init = (sctp_init_chunk_t *)skb->data; 947 948 /* Walk the parameters looking for embedded addresses. */ 949 sctp_walk_params(params, init, init_hdr.params) { 950 951 /* Note: Ignoring hostname addresses. */ 952 af = sctp_get_af_specific(param_type2af(params.p->type)); 953 if (!af) 954 continue; 955 956 af->from_addr_param(paddr, params.addr, sh->source, 0); 957 958 asoc = __sctp_lookup_association(laddr, paddr, &transport); 959 if (asoc) 960 return asoc; 961 } 962 963 return NULL; 964} 965 966/* Lookup an association for an inbound skb. */ 967static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, 968 const union sctp_addr *paddr, 969 const union sctp_addr *laddr, 970 struct sctp_transport **transportp) 971{ 972 struct sctp_association *asoc; 973 974 asoc = __sctp_lookup_association(laddr, paddr, transportp); 975 976 /* Further lookup for INIT/INIT-ACK packets. 977 * SCTP Implementors Guide, 2.18 Handling of address 978 * parameters within the INIT or INIT-ACK. 979 */ 980 if (!asoc) 981 asoc = __sctp_rcv_init_lookup(skb, laddr, transportp); 982 983 return asoc; 984} 985