ia64/linux-2.6.18-xen.hg

view net/sctp/input.c @ 871:9cbcc9008446

xen/x86: don't initialize cpu_data[]'s apicid field on generic code

Afaict, this is not only redundant with the intialization done in
drivers/xen/core/smpboot.c, but actually results - at least for
secondary CPUs - in the Xen-specific value written to be later
overwritten with whatever the generic code determines (with no
guarantee that the two values are identical).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu May 14 10:09:15 2009 +0100 (2009-05-14)
parents 3e8752eb6d9c
children
line source
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 */
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>
64 /* Forward declarations for internal helpers. */
65 static int sctp_rcv_ootb(struct sk_buff *);
66 static 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);
70 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr);
71 static struct sctp_association *__sctp_lookup_association(
72 const union sctp_addr *local,
73 const union sctp_addr *peer,
74 struct sctp_transport **pt);
76 static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
79 /* Calculate the SCTP checksum of an SCTP packet. */
80 static inline int sctp_rcv_checksum(struct sk_buff *skb)
81 {
82 struct sctphdr *sh;
83 __u32 cmp, val;
84 struct sk_buff *list = skb_shinfo(skb)->frag_list;
86 sh = (struct sctphdr *) skb->h.raw;
87 cmp = ntohl(sh->checksum);
89 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
91 for (; list; list = list->next)
92 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
93 val);
95 val = sctp_end_cksum(val);
97 if (val != cmp) {
98 /* CRC failure, dump it. */
99 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS);
100 return -1;
101 }
102 return 0;
103 }
105 struct sctp_input_cb {
106 union {
107 struct inet_skb_parm h4;
108 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
109 struct inet6_skb_parm h6;
110 #endif
111 } header;
112 struct sctp_chunk *chunk;
113 };
114 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
116 /*
117 * This is the routine which IP calls when receiving an SCTP packet.
118 */
119 int sctp_rcv(struct sk_buff *skb)
120 {
121 struct sock *sk;
122 struct sctp_association *asoc;
123 struct sctp_endpoint *ep = NULL;
124 struct sctp_ep_common *rcvr;
125 struct sctp_transport *transport = NULL;
126 struct sctp_chunk *chunk;
127 struct sctphdr *sh;
128 union sctp_addr src;
129 union sctp_addr dest;
130 int family;
131 struct sctp_af *af;
133 if (skb->pkt_type!=PACKET_HOST)
134 goto discard_it;
136 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
138 if (skb_linearize(skb))
139 goto discard_it;
141 sh = (struct sctphdr *) skb->h.raw;
143 /* Pull up the IP and SCTP headers. */
144 __skb_pull(skb, skb->h.raw - skb->data);
145 if (skb->len < sizeof(struct sctphdr))
146 goto discard_it;
147 if ((skb->ip_summed != CHECKSUM_UNNECESSARY) &&
148 (sctp_rcv_checksum(skb) < 0))
149 goto discard_it;
151 skb_pull(skb, sizeof(struct sctphdr));
153 /* Make sure we at least have chunk headers worth of data left. */
154 if (skb->len < sizeof(struct sctp_chunkhdr))
155 goto discard_it;
157 family = ipver2af(skb->nh.iph->version);
158 af = sctp_get_af_specific(family);
159 if (unlikely(!af))
160 goto discard_it;
162 /* Initialize local addresses for lookups. */
163 af->from_skb(&src, skb, 1);
164 af->from_skb(&dest, skb, 0);
166 /* If the packet is to or from a non-unicast address,
167 * silently discard the packet.
168 *
169 * This is not clearly defined in the RFC except in section
170 * 8.4 - OOTB handling. However, based on the book "Stream Control
171 * Transmission Protocol" 2.1, "It is important to note that the
172 * IP address of an SCTP transport address must be a routable
173 * unicast address. In other words, IP multicast addresses and
174 * IP broadcast addresses cannot be used in an SCTP transport
175 * address."
176 */
177 if (!af->addr_valid(&src, NULL, skb) ||
178 !af->addr_valid(&dest, NULL, skb))
179 goto discard_it;
181 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
183 if (!asoc)
184 ep = __sctp_rcv_lookup_endpoint(&dest);
186 /* Retrieve the common input handling substructure. */
187 rcvr = asoc ? &asoc->base : &ep->base;
188 sk = rcvr->sk;
190 /*
191 * If a frame arrives on an interface and the receiving socket is
192 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
193 */
194 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
195 {
196 if (asoc) {
197 sctp_association_put(asoc);
198 asoc = NULL;
199 } else {
200 sctp_endpoint_put(ep);
201 ep = NULL;
202 }
203 sk = sctp_get_ctl_sock();
204 ep = sctp_sk(sk)->ep;
205 sctp_endpoint_hold(ep);
206 rcvr = &ep->base;
207 }
209 /*
210 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
211 * An SCTP packet is called an "out of the blue" (OOTB)
212 * packet if it is correctly formed, i.e., passed the
213 * receiver's checksum check, but the receiver is not
214 * able to identify the association to which this
215 * packet belongs.
216 */
217 if (!asoc) {
218 if (sctp_rcv_ootb(skb)) {
219 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
220 goto discard_release;
221 }
222 }
224 /* SCTP seems to always need a timestamp right now (FIXME) */
225 if (skb->tstamp.off_sec == 0) {
226 __net_timestamp(skb);
227 sock_enable_timestamp(sk);
228 }
230 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
231 goto discard_release;
232 nf_reset(skb);
234 if (sk_filter(sk, skb, 1))
235 goto discard_release;
237 /* Create an SCTP packet structure. */
238 chunk = sctp_chunkify(skb, asoc, sk);
239 if (!chunk)
240 goto discard_release;
241 SCTP_INPUT_CB(skb)->chunk = chunk;
243 /* Remember what endpoint is to handle this packet. */
244 chunk->rcvr = rcvr;
246 /* Remember the SCTP header. */
247 chunk->sctp_hdr = sh;
249 /* Set the source and destination addresses of the incoming chunk. */
250 sctp_init_addrs(chunk, &src, &dest);
252 /* Remember where we came from. */
253 chunk->transport = transport;
255 /* Acquire access to the sock lock. Note: We are safe from other
256 * bottom halves on this lock, but a user may be in the lock too,
257 * so check if it is busy.
258 */
259 sctp_bh_lock_sock(sk);
261 if (sock_owned_by_user(sk))
262 sctp_add_backlog(sk, skb);
263 else
264 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
266 sctp_bh_unlock_sock(sk);
268 /* Release the asoc/ep ref we took in the lookup calls. */
269 if (asoc)
270 sctp_association_put(asoc);
271 else
272 sctp_endpoint_put(ep);
274 return 0;
276 discard_it:
277 kfree_skb(skb);
278 return 0;
280 discard_release:
281 /* Release the asoc/ep ref we took in the lookup calls. */
282 if (asoc)
283 sctp_association_put(asoc);
284 else
285 sctp_endpoint_put(ep);
287 goto discard_it;
288 }
290 /* Process the backlog queue of the socket. Every skb on
291 * the backlog holds a ref on an association or endpoint.
292 * We hold this ref throughout the state machine to make
293 * sure that the structure we need is still around.
294 */
295 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
296 {
297 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
298 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
299 struct sctp_ep_common *rcvr = NULL;
300 int backloged = 0;
302 rcvr = chunk->rcvr;
304 /* If the rcvr is dead then the association or endpoint
305 * has been deleted and we can safely drop the chunk
306 * and refs that we are holding.
307 */
308 if (rcvr->dead) {
309 sctp_chunk_free(chunk);
310 goto done;
311 }
313 if (unlikely(rcvr->sk != sk)) {
314 /* In this case, the association moved from one socket to
315 * another. We are currently sitting on the backlog of the
316 * old socket, so we need to move.
317 * However, since we are here in the process context we
318 * need to take make sure that the user doesn't own
319 * the new socket when we process the packet.
320 * If the new socket is user-owned, queue the chunk to the
321 * backlog of the new socket without dropping any refs.
322 * Otherwise, we can safely push the chunk on the inqueue.
323 */
325 sk = rcvr->sk;
326 sctp_bh_lock_sock(sk);
328 if (sock_owned_by_user(sk)) {
329 sk_add_backlog(sk, skb);
330 backloged = 1;
331 } else
332 sctp_inq_push(inqueue, chunk);
334 sctp_bh_unlock_sock(sk);
336 /* If the chunk was backloged again, don't drop refs */
337 if (backloged)
338 return 0;
339 } else {
340 sctp_inq_push(inqueue, chunk);
341 }
343 done:
344 /* Release the refs we took in sctp_add_backlog */
345 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
346 sctp_association_put(sctp_assoc(rcvr));
347 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
348 sctp_endpoint_put(sctp_ep(rcvr));
349 else
350 BUG();
352 return 0;
353 }
355 static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
356 {
357 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
358 struct sctp_ep_common *rcvr = chunk->rcvr;
360 /* Hold the assoc/ep while hanging on the backlog queue.
361 * This way, we know structures we need will not disappear from us
362 */
363 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
364 sctp_association_hold(sctp_assoc(rcvr));
365 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
366 sctp_endpoint_hold(sctp_ep(rcvr));
367 else
368 BUG();
370 sk_add_backlog(sk, skb);
371 }
373 /* Handle icmp frag needed error. */
374 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
375 struct sctp_transport *t, __u32 pmtu)
376 {
377 if (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu))
378 return;
380 if (t->param_flags & SPP_PMTUD_ENABLE) {
381 if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
382 printk(KERN_WARNING "%s: Reported pmtu %d too low, "
383 "using default minimum of %d\n",
384 __FUNCTION__, pmtu,
385 SCTP_DEFAULT_MINSEGMENT);
386 /* Use default minimum segment size and disable
387 * pmtu discovery on this transport.
388 */
389 t->pathmtu = SCTP_DEFAULT_MINSEGMENT;
390 t->param_flags = (t->param_flags & ~SPP_HB) |
391 SPP_PMTUD_DISABLE;
392 } else {
393 t->pathmtu = pmtu;
394 }
396 /* Update association pmtu. */
397 sctp_assoc_sync_pmtu(asoc);
398 }
400 /* Retransmit with the new pmtu setting.
401 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
402 * Needed will never be sent, but if a message was sent before
403 * PMTU discovery was disabled that was larger than the PMTU, it
404 * would not be fragmented, so it must be re-transmitted fragmented.
405 */
406 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
407 }
409 /*
410 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
411 *
412 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
413 * or a "Protocol Unreachable" treat this message as an abort
414 * with the T bit set.
415 *
416 * This function sends an event to the state machine, which will abort the
417 * association.
418 *
419 */
420 void sctp_icmp_proto_unreachable(struct sock *sk,
421 struct sctp_association *asoc,
422 struct sctp_transport *t)
423 {
424 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__);
426 sctp_do_sm(SCTP_EVENT_T_OTHER,
427 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
428 asoc->state, asoc->ep, asoc, t,
429 GFP_ATOMIC);
431 }
433 /* Common lookup code for icmp/icmpv6 error handler. */
434 struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
435 struct sctphdr *sctphdr,
436 struct sctp_association **app,
437 struct sctp_transport **tpp)
438 {
439 union sctp_addr saddr;
440 union sctp_addr daddr;
441 struct sctp_af *af;
442 struct sock *sk = NULL;
443 struct sctp_association *asoc;
444 struct sctp_transport *transport = NULL;
446 *app = NULL; *tpp = NULL;
448 af = sctp_get_af_specific(family);
449 if (unlikely(!af)) {
450 return NULL;
451 }
453 /* Initialize local addresses for lookups. */
454 af->from_skb(&saddr, skb, 1);
455 af->from_skb(&daddr, skb, 0);
457 /* Look for an association that matches the incoming ICMP error
458 * packet.
459 */
460 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
461 if (!asoc)
462 return NULL;
464 sk = asoc->base.sk;
466 if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
467 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
468 goto out;
469 }
471 sctp_bh_lock_sock(sk);
473 /* If too many ICMPs get dropped on busy
474 * servers this needs to be solved differently.
475 */
476 if (sock_owned_by_user(sk))
477 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
479 *app = asoc;
480 *tpp = transport;
481 return sk;
483 out:
484 if (asoc)
485 sctp_association_put(asoc);
486 return NULL;
487 }
489 /* Common cleanup code for icmp/icmpv6 error handler. */
490 void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
491 {
492 sctp_bh_unlock_sock(sk);
493 if (asoc)
494 sctp_association_put(asoc);
495 }
497 /*
498 * This routine is called by the ICMP module when it gets some
499 * sort of error condition. If err < 0 then the socket should
500 * be closed and the error returned to the user. If err > 0
501 * it's just the icmp type << 8 | icmp code. After adjustment
502 * header points to the first 8 bytes of the sctp header. We need
503 * to find the appropriate port.
504 *
505 * The locking strategy used here is very "optimistic". When
506 * someone else accesses the socket the ICMP is just dropped
507 * and for some paths there is no check at all.
508 * A more general error queue to queue errors for later handling
509 * is probably better.
510 *
511 */
512 void sctp_v4_err(struct sk_buff *skb, __u32 info)
513 {
514 struct iphdr *iph = (struct iphdr *)skb->data;
515 struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2));
516 int type = skb->h.icmph->type;
517 int code = skb->h.icmph->code;
518 struct sock *sk;
519 struct sctp_association *asoc = NULL;
520 struct sctp_transport *transport;
521 struct inet_sock *inet;
522 char *saveip, *savesctp;
523 int err;
525 if (skb->len < ((iph->ihl << 2) + 8)) {
526 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
527 return;
528 }
530 /* Fix up skb to look at the embedded net header. */
531 saveip = skb->nh.raw;
532 savesctp = skb->h.raw;
533 skb->nh.iph = iph;
534 skb->h.raw = (char *)sh;
535 sk = sctp_err_lookup(AF_INET, skb, sh, &asoc, &transport);
536 /* Put back, the original pointers. */
537 skb->nh.raw = saveip;
538 skb->h.raw = savesctp;
539 if (!sk) {
540 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
541 return;
542 }
543 /* Warning: The sock lock is held. Remember to call
544 * sctp_err_finish!
545 */
547 switch (type) {
548 case ICMP_PARAMETERPROB:
549 err = EPROTO;
550 break;
551 case ICMP_DEST_UNREACH:
552 if (code > NR_ICMP_UNREACH)
553 goto out_unlock;
555 /* PMTU discovery (RFC1191) */
556 if (ICMP_FRAG_NEEDED == code) {
557 sctp_icmp_frag_needed(sk, asoc, transport, info);
558 goto out_unlock;
559 }
560 else {
561 if (ICMP_PROT_UNREACH == code) {
562 sctp_icmp_proto_unreachable(sk, asoc,
563 transport);
564 goto out_unlock;
565 }
566 }
567 err = icmp_err_convert[code].errno;
568 break;
569 case ICMP_TIME_EXCEEDED:
570 /* Ignore any time exceeded errors due to fragment reassembly
571 * timeouts.
572 */
573 if (ICMP_EXC_FRAGTIME == code)
574 goto out_unlock;
576 err = EHOSTUNREACH;
577 break;
578 default:
579 goto out_unlock;
580 }
582 inet = inet_sk(sk);
583 if (!sock_owned_by_user(sk) && inet->recverr) {
584 sk->sk_err = err;
585 sk->sk_error_report(sk);
586 } else { /* Only an error on timeout */
587 sk->sk_err_soft = err;
588 }
590 out_unlock:
591 sctp_err_finish(sk, asoc);
592 }
594 /*
595 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
596 *
597 * This function scans all the chunks in the OOTB packet to determine if
598 * the packet should be discarded right away. If a response might be needed
599 * for this packet, or, if further processing is possible, the packet will
600 * be queued to a proper inqueue for the next phase of handling.
601 *
602 * Output:
603 * Return 0 - If further processing is needed.
604 * Return 1 - If the packet can be discarded right away.
605 */
606 int sctp_rcv_ootb(struct sk_buff *skb)
607 {
608 sctp_chunkhdr_t *ch;
609 __u8 *ch_end;
610 sctp_errhdr_t *err;
612 ch = (sctp_chunkhdr_t *) skb->data;
614 /* Scan through all the chunks in the packet. */
615 do {
616 /* Break out if chunk length is less then minimal. */
617 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
618 break;
620 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
621 if (ch_end > skb->tail)
622 break;
624 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
625 * receiver MUST silently discard the OOTB packet and take no
626 * further action.
627 */
628 if (SCTP_CID_ABORT == ch->type)
629 goto discard;
631 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
632 * chunk, the receiver should silently discard the packet
633 * and take no further action.
634 */
635 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
636 goto discard;
638 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
639 * or a COOKIE ACK the SCTP Packet should be silently
640 * discarded.
641 */
642 if (SCTP_CID_COOKIE_ACK == ch->type)
643 goto discard;
645 if (SCTP_CID_ERROR == ch->type) {
646 sctp_walk_errors(err, ch) {
647 if (SCTP_ERROR_STALE_COOKIE == err->cause)
648 goto discard;
649 }
650 }
652 ch = (sctp_chunkhdr_t *) ch_end;
653 } while (ch_end < skb->tail);
655 return 0;
657 discard:
658 return 1;
659 }
661 /* Insert endpoint into the hash table. */
662 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
663 {
664 struct sctp_ep_common **epp;
665 struct sctp_ep_common *epb;
666 struct sctp_hashbucket *head;
668 epb = &ep->base;
670 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
671 head = &sctp_ep_hashtable[epb->hashent];
673 sctp_write_lock(&head->lock);
674 epp = &head->chain;
675 epb->next = *epp;
676 if (epb->next)
677 (*epp)->pprev = &epb->next;
678 *epp = epb;
679 epb->pprev = epp;
680 sctp_write_unlock(&head->lock);
681 }
683 /* Add an endpoint to the hash. Local BH-safe. */
684 void sctp_hash_endpoint(struct sctp_endpoint *ep)
685 {
686 sctp_local_bh_disable();
687 __sctp_hash_endpoint(ep);
688 sctp_local_bh_enable();
689 }
691 /* Remove endpoint from the hash table. */
692 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
693 {
694 struct sctp_hashbucket *head;
695 struct sctp_ep_common *epb;
697 epb = &ep->base;
699 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
701 head = &sctp_ep_hashtable[epb->hashent];
703 sctp_write_lock(&head->lock);
705 if (epb->pprev) {
706 if (epb->next)
707 epb->next->pprev = epb->pprev;
708 *epb->pprev = epb->next;
709 epb->pprev = NULL;
710 }
712 sctp_write_unlock(&head->lock);
713 }
715 /* Remove endpoint from the hash. Local BH-safe. */
716 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
717 {
718 sctp_local_bh_disable();
719 __sctp_unhash_endpoint(ep);
720 sctp_local_bh_enable();
721 }
723 /* Look up an endpoint. */
724 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
725 {
726 struct sctp_hashbucket *head;
727 struct sctp_ep_common *epb;
728 struct sctp_endpoint *ep;
729 int hash;
731 hash = sctp_ep_hashfn(laddr->v4.sin_port);
732 head = &sctp_ep_hashtable[hash];
733 read_lock(&head->lock);
734 for (epb = head->chain; epb; epb = epb->next) {
735 ep = sctp_ep(epb);
736 if (sctp_endpoint_is_match(ep, laddr))
737 goto hit;
738 }
740 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
741 epb = &ep->base;
743 hit:
744 sctp_endpoint_hold(ep);
745 read_unlock(&head->lock);
746 return ep;
747 }
749 /* Insert association into the hash table. */
750 static void __sctp_hash_established(struct sctp_association *asoc)
751 {
752 struct sctp_ep_common **epp;
753 struct sctp_ep_common *epb;
754 struct sctp_hashbucket *head;
756 epb = &asoc->base;
758 /* Calculate which chain this entry will belong to. */
759 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
761 head = &sctp_assoc_hashtable[epb->hashent];
763 sctp_write_lock(&head->lock);
764 epp = &head->chain;
765 epb->next = *epp;
766 if (epb->next)
767 (*epp)->pprev = &epb->next;
768 *epp = epb;
769 epb->pprev = epp;
770 sctp_write_unlock(&head->lock);
771 }
773 /* Add an association to the hash. Local BH-safe. */
774 void sctp_hash_established(struct sctp_association *asoc)
775 {
776 sctp_local_bh_disable();
777 __sctp_hash_established(asoc);
778 sctp_local_bh_enable();
779 }
781 /* Remove association from the hash table. */
782 static void __sctp_unhash_established(struct sctp_association *asoc)
783 {
784 struct sctp_hashbucket *head;
785 struct sctp_ep_common *epb;
787 epb = &asoc->base;
789 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
790 asoc->peer.port);
792 head = &sctp_assoc_hashtable[epb->hashent];
794 sctp_write_lock(&head->lock);
796 if (epb->pprev) {
797 if (epb->next)
798 epb->next->pprev = epb->pprev;
799 *epb->pprev = epb->next;
800 epb->pprev = NULL;
801 }
803 sctp_write_unlock(&head->lock);
804 }
806 /* Remove association from the hash table. Local BH-safe. */
807 void sctp_unhash_established(struct sctp_association *asoc)
808 {
809 sctp_local_bh_disable();
810 __sctp_unhash_established(asoc);
811 sctp_local_bh_enable();
812 }
814 /* Look up an association. */
815 static 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;
826 /* Optimize here for direct hit, only listening connections can
827 * have wildcards anyways.
828 */
829 hash = sctp_assoc_hashfn(local->v4.sin_port, 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 }
839 read_unlock(&head->lock);
841 return NULL;
843 hit:
844 *pt = transport;
845 sctp_association_hold(asoc);
846 read_unlock(&head->lock);
847 return asoc;
848 }
850 /* Look up an association. BH-safe. */
851 SCTP_STATIC
852 struct 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;
858 sctp_local_bh_disable();
859 asoc = __sctp_lookup_association(laddr, paddr, transportp);
860 sctp_local_bh_enable();
862 return asoc;
863 }
865 /* Is there an association matching the given local and peer addresses? */
866 int 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;
872 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
873 sctp_association_put(asoc);
874 return 1;
875 }
877 return 0;
878 }
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 */
898 static 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 = (struct sctphdr *) skb->h.raw;
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;
911 ch = (sctp_chunkhdr_t *) skb->data;
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 }
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;
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 */
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;
948 /* Walk the parameters looking for embedded addresses. */
949 sctp_walk_params(params, init, init_hdr.params) {
951 /* Note: Ignoring hostname addresses. */
952 af = sctp_get_af_specific(param_type2af(params.p->type));
953 if (!af)
954 continue;
956 af->from_addr_param(paddr, params.addr, ntohs(sh->source), 0);
958 asoc = __sctp_lookup_association(laddr, paddr, &transport);
959 if (asoc)
960 return asoc;
961 }
963 return NULL;
964 }
966 /* Lookup an association for an inbound skb. */
967 static 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;
974 asoc = __sctp_lookup_association(laddr, paddr, transportp);
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);
983 return asoc;
984 }