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
9 * This file is part of the SCTP kernel reference Implementation
11 * These functions handle all input from the IP layer into SCTP.
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)
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.
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.
30 * Please send any bug reports or fixes you make to the
32 * lksctp developers <lksctp-developers@lists.sourceforge.net>
34 * Or submit a bug report through the following website:
35 * http://www.sf.net/projects/lksctp
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>
47 * Any bugs reported given to us we will try to fix... any fixes shared will
48 * be incorporated into the next SCTP release.
51 #include <linux/types.h>
52 #include <linux/list.h> /* For struct list_head */
53 #include <linux/socket.h>
55 #include <linux/time.h> /* For struct timeval */
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
)
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
),
95 val
= sctp_end_cksum(val
);
98 /* CRC failure, dump it. */
99 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS
);
105 struct sctp_input_cb
{
107 struct inet_skb_parm h4
;
108 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
109 struct inet6_skb_parm h6
;
112 struct sctp_chunk
*chunk
;
114 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
117 * This is the routine which IP calls when receiving an SCTP packet.
119 int sctp_rcv(struct sk_buff
*skb
)
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
;
129 union sctp_addr dest
;
130 union sctp_addr tmp
, tmp2
;
134 if (skb
->pkt_type
!=PACKET_HOST
)
137 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS
);
139 if (skb_linearize(skb
))
142 sh
= (struct sctphdr
*) skb
->h
.raw
;
144 /* Pull up the IP and SCTP headers. */
145 __skb_pull(skb
, skb
->h
.raw
- skb
->data
);
146 if (skb
->len
< sizeof(struct sctphdr
))
148 if ((skb
->ip_summed
!= CHECKSUM_UNNECESSARY
) &&
149 (sctp_rcv_checksum(skb
) < 0))
152 skb_pull(skb
, sizeof(struct sctphdr
));
154 /* Make sure we at least have chunk headers worth of data left. */
155 if (skb
->len
< sizeof(struct sctp_chunkhdr
))
158 family
= ipver2af(skb
->nh
.iph
->version
);
159 af
= sctp_get_af_specific(family
);
163 /* Initialize local addresses for lookups. */
164 af
->from_skb(&src
, skb
, 1);
165 af
->from_skb(&dest
, skb
, 0);
167 /* If the packet is to or from a non-unicast address,
168 * silently discard the packet.
170 * This is not clearly defined in the RFC except in section
171 * 8.4 - OOTB handling. However, based on the book "Stream Control
172 * Transmission Protocol" 2.1, "It is important to note that the
173 * IP address of an SCTP transport address must be a routable
174 * unicast address. In other words, IP multicast addresses and
175 * IP broadcast addresses cannot be used in an SCTP transport
178 if (!af
->addr_valid(&src
, NULL
, skb
) ||
179 !af
->addr_valid(&dest
, NULL
, skb
))
182 flip_to_n(&tmp
, &dest
);
183 flip_to_n(&tmp2
, &src
);
185 asoc
= __sctp_rcv_lookup(skb
, &tmp2
, &tmp
, &transport
);
188 ep
= __sctp_rcv_lookup_endpoint(&tmp
);
190 /* Retrieve the common input handling substructure. */
191 rcvr
= asoc
? &asoc
->base
: &ep
->base
;
195 * If a frame arrives on an interface and the receiving socket is
196 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
198 if (sk
->sk_bound_dev_if
&& (sk
->sk_bound_dev_if
!= af
->skb_iif(skb
)))
201 sctp_association_put(asoc
);
204 sctp_endpoint_put(ep
);
207 sk
= sctp_get_ctl_sock();
208 ep
= sctp_sk(sk
)->ep
;
209 sctp_endpoint_hold(ep
);
214 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
215 * An SCTP packet is called an "out of the blue" (OOTB)
216 * packet if it is correctly formed, i.e., passed the
217 * receiver's checksum check, but the receiver is not
218 * able to identify the association to which this
222 if (sctp_rcv_ootb(skb
)) {
223 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES
);
224 goto discard_release
;
228 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
229 goto discard_release
;
232 if (sk_filter(sk
, skb
))
233 goto discard_release
;
235 /* Create an SCTP packet structure. */
236 chunk
= sctp_chunkify(skb
, asoc
, sk
);
238 goto discard_release
;
239 SCTP_INPUT_CB(skb
)->chunk
= chunk
;
241 /* Remember what endpoint is to handle this packet. */
244 /* Remember the SCTP header. */
245 chunk
->sctp_hdr
= sh
;
247 /* Set the source and destination addresses of the incoming chunk. */
248 sctp_init_addrs(chunk
, &src
, &dest
);
250 /* Remember where we came from. */
251 chunk
->transport
= transport
;
253 /* Acquire access to the sock lock. Note: We are safe from other
254 * bottom halves on this lock, but a user may be in the lock too,
255 * so check if it is busy.
257 sctp_bh_lock_sock(sk
);
259 if (sock_owned_by_user(sk
)) {
260 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG
);
261 sctp_add_backlog(sk
, skb
);
263 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ
);
264 sctp_inq_push(&chunk
->rcvr
->inqueue
, chunk
);
267 sctp_bh_unlock_sock(sk
);
269 /* Release the asoc/ep ref we took in the lookup calls. */
271 sctp_association_put(asoc
);
273 sctp_endpoint_put(ep
);
278 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS
);
283 /* Release the asoc/ep ref we took in the lookup calls. */
285 sctp_association_put(asoc
);
287 sctp_endpoint_put(ep
);
292 /* Process the backlog queue of the socket. Every skb on
293 * the backlog holds a ref on an association or endpoint.
294 * We hold this ref throughout the state machine to make
295 * sure that the structure we need is still around.
297 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
299 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
300 struct sctp_inq
*inqueue
= &chunk
->rcvr
->inqueue
;
301 struct sctp_ep_common
*rcvr
= NULL
;
306 /* If the rcvr is dead then the association or endpoint
307 * has been deleted and we can safely drop the chunk
308 * and refs that we are holding.
311 sctp_chunk_free(chunk
);
315 if (unlikely(rcvr
->sk
!= sk
)) {
316 /* In this case, the association moved from one socket to
317 * another. We are currently sitting on the backlog of the
318 * old socket, so we need to move.
319 * However, since we are here in the process context we
320 * need to take make sure that the user doesn't own
321 * the new socket when we process the packet.
322 * If the new socket is user-owned, queue the chunk to the
323 * backlog of the new socket without dropping any refs.
324 * Otherwise, we can safely push the chunk on the inqueue.
328 sctp_bh_lock_sock(sk
);
330 if (sock_owned_by_user(sk
)) {
331 sk_add_backlog(sk
, skb
);
334 sctp_inq_push(inqueue
, chunk
);
336 sctp_bh_unlock_sock(sk
);
338 /* If the chunk was backloged again, don't drop refs */
342 sctp_inq_push(inqueue
, chunk
);
346 /* Release the refs we took in sctp_add_backlog */
347 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
348 sctp_association_put(sctp_assoc(rcvr
));
349 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
350 sctp_endpoint_put(sctp_ep(rcvr
));
357 static void sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
359 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
360 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
362 /* Hold the assoc/ep while hanging on the backlog queue.
363 * This way, we know structures we need will not disappear from us
365 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
366 sctp_association_hold(sctp_assoc(rcvr
));
367 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
368 sctp_endpoint_hold(sctp_ep(rcvr
));
372 sk_add_backlog(sk
, skb
);
375 /* Handle icmp frag needed error. */
376 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
377 struct sctp_transport
*t
, __u32 pmtu
)
379 if (sock_owned_by_user(sk
) || !t
|| (t
->pathmtu
== pmtu
))
382 if (t
->param_flags
& SPP_PMTUD_ENABLE
) {
383 if (unlikely(pmtu
< SCTP_DEFAULT_MINSEGMENT
)) {
384 printk(KERN_WARNING
"%s: Reported pmtu %d too low, "
385 "using default minimum of %d\n",
387 SCTP_DEFAULT_MINSEGMENT
);
388 /* Use default minimum segment size and disable
389 * pmtu discovery on this transport.
391 t
->pathmtu
= SCTP_DEFAULT_MINSEGMENT
;
392 t
->param_flags
= (t
->param_flags
& ~SPP_PMTUD
) |
398 /* Update association pmtu. */
399 sctp_assoc_sync_pmtu(asoc
);
402 /* Retransmit with the new pmtu setting.
403 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
404 * Needed will never be sent, but if a message was sent before
405 * PMTU discovery was disabled that was larger than the PMTU, it
406 * would not be fragmented, so it must be re-transmitted fragmented.
408 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
412 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
414 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
415 * or a "Protocol Unreachable" treat this message as an abort
416 * with the T bit set.
418 * This function sends an event to the state machine, which will abort the
422 void sctp_icmp_proto_unreachable(struct sock
*sk
,
423 struct sctp_association
*asoc
,
424 struct sctp_transport
*t
)
426 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__
);
428 sctp_do_sm(SCTP_EVENT_T_OTHER
,
429 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
430 asoc
->state
, asoc
->ep
, asoc
, t
,
435 /* Common lookup code for icmp/icmpv6 error handler. */
436 struct sock
*sctp_err_lookup(int family
, struct sk_buff
*skb
,
437 struct sctphdr
*sctphdr
,
438 struct sctp_association
**app
,
439 struct sctp_transport
**tpp
)
441 union sctp_addr saddr
;
442 union sctp_addr daddr
;
444 struct sock
*sk
= NULL
;
445 struct sctp_association
*asoc
;
446 struct sctp_transport
*transport
= NULL
;
447 union sctp_addr tmp
, tmp2
;
449 *app
= NULL
; *tpp
= NULL
;
451 af
= sctp_get_af_specific(family
);
456 /* Initialize local addresses for lookups. */
457 af
->from_skb(&saddr
, skb
, 1);
458 af
->from_skb(&daddr
, skb
, 0);
459 flip_to_n(&tmp
, &saddr
);
460 flip_to_n(&tmp2
, &daddr
);
462 /* Look for an association that matches the incoming ICMP error
465 asoc
= __sctp_lookup_association(&tmp
, &tmp2
, &transport
);
471 if (ntohl(sctphdr
->vtag
) != asoc
->c
.peer_vtag
) {
472 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
476 sctp_bh_lock_sock(sk
);
478 /* If too many ICMPs get dropped on busy
479 * servers this needs to be solved differently.
481 if (sock_owned_by_user(sk
))
482 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS
);
490 sctp_association_put(asoc
);
494 /* Common cleanup code for icmp/icmpv6 error handler. */
495 void sctp_err_finish(struct sock
*sk
, struct sctp_association
*asoc
)
497 sctp_bh_unlock_sock(sk
);
499 sctp_association_put(asoc
);
503 * This routine is called by the ICMP module when it gets some
504 * sort of error condition. If err < 0 then the socket should
505 * be closed and the error returned to the user. If err > 0
506 * it's just the icmp type << 8 | icmp code. After adjustment
507 * header points to the first 8 bytes of the sctp header. We need
508 * to find the appropriate port.
510 * The locking strategy used here is very "optimistic". When
511 * someone else accesses the socket the ICMP is just dropped
512 * and for some paths there is no check at all.
513 * A more general error queue to queue errors for later handling
514 * is probably better.
517 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
519 struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
520 struct sctphdr
*sh
= (struct sctphdr
*)(skb
->data
+ (iph
->ihl
<<2));
521 int type
= skb
->h
.icmph
->type
;
522 int code
= skb
->h
.icmph
->code
;
524 struct sctp_association
*asoc
= NULL
;
525 struct sctp_transport
*transport
;
526 struct inet_sock
*inet
;
527 char *saveip
, *savesctp
;
530 if (skb
->len
< ((iph
->ihl
<< 2) + 8)) {
531 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
535 /* Fix up skb to look at the embedded net header. */
536 saveip
= skb
->nh
.raw
;
537 savesctp
= skb
->h
.raw
;
539 skb
->h
.raw
= (char *)sh
;
540 sk
= sctp_err_lookup(AF_INET
, skb
, sh
, &asoc
, &transport
);
541 /* Put back, the original pointers. */
542 skb
->nh
.raw
= saveip
;
543 skb
->h
.raw
= savesctp
;
545 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
548 /* Warning: The sock lock is held. Remember to call
553 case ICMP_PARAMETERPROB
:
556 case ICMP_DEST_UNREACH
:
557 if (code
> NR_ICMP_UNREACH
)
560 /* PMTU discovery (RFC1191) */
561 if (ICMP_FRAG_NEEDED
== code
) {
562 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
566 if (ICMP_PROT_UNREACH
== code
) {
567 sctp_icmp_proto_unreachable(sk
, asoc
,
572 err
= icmp_err_convert
[code
].errno
;
574 case ICMP_TIME_EXCEEDED
:
575 /* Ignore any time exceeded errors due to fragment reassembly
578 if (ICMP_EXC_FRAGTIME
== code
)
588 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
590 sk
->sk_error_report(sk
);
591 } else { /* Only an error on timeout */
592 sk
->sk_err_soft
= err
;
596 sctp_err_finish(sk
, asoc
);
600 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
602 * This function scans all the chunks in the OOTB packet to determine if
603 * the packet should be discarded right away. If a response might be needed
604 * for this packet, or, if further processing is possible, the packet will
605 * be queued to a proper inqueue for the next phase of handling.
608 * Return 0 - If further processing is needed.
609 * Return 1 - If the packet can be discarded right away.
611 int sctp_rcv_ootb(struct sk_buff
*skb
)
617 ch
= (sctp_chunkhdr_t
*) skb
->data
;
619 /* Scan through all the chunks in the packet. */
621 /* Break out if chunk length is less then minimal. */
622 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
625 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
626 if (ch_end
> skb
->tail
)
629 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
630 * receiver MUST silently discard the OOTB packet and take no
633 if (SCTP_CID_ABORT
== ch
->type
)
636 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
637 * chunk, the receiver should silently discard the packet
638 * and take no further action.
640 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
643 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
644 * or a COOKIE ACK the SCTP Packet should be silently
647 if (SCTP_CID_COOKIE_ACK
== ch
->type
)
650 if (SCTP_CID_ERROR
== ch
->type
) {
651 sctp_walk_errors(err
, ch
) {
652 if (SCTP_ERROR_STALE_COOKIE
== err
->cause
)
657 ch
= (sctp_chunkhdr_t
*) ch_end
;
658 } while (ch_end
< skb
->tail
);
666 /* Insert endpoint into the hash table. */
667 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
669 struct sctp_ep_common
**epp
;
670 struct sctp_ep_common
*epb
;
671 struct sctp_hashbucket
*head
;
675 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
676 head
= &sctp_ep_hashtable
[epb
->hashent
];
678 sctp_write_lock(&head
->lock
);
682 (*epp
)->pprev
= &epb
->next
;
685 sctp_write_unlock(&head
->lock
);
688 /* Add an endpoint to the hash. Local BH-safe. */
689 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
691 sctp_local_bh_disable();
692 __sctp_hash_endpoint(ep
);
693 sctp_local_bh_enable();
696 /* Remove endpoint from the hash table. */
697 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
699 struct sctp_hashbucket
*head
;
700 struct sctp_ep_common
*epb
;
704 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
706 head
= &sctp_ep_hashtable
[epb
->hashent
];
708 sctp_write_lock(&head
->lock
);
712 epb
->next
->pprev
= epb
->pprev
;
713 *epb
->pprev
= epb
->next
;
717 sctp_write_unlock(&head
->lock
);
720 /* Remove endpoint from the hash. Local BH-safe. */
721 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
723 sctp_local_bh_disable();
724 __sctp_unhash_endpoint(ep
);
725 sctp_local_bh_enable();
728 /* Look up an endpoint. */
729 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(const union sctp_addr
*laddr
)
731 struct sctp_hashbucket
*head
;
732 struct sctp_ep_common
*epb
;
733 struct sctp_endpoint
*ep
;
736 hash
= sctp_ep_hashfn(ntohs(laddr
->v4
.sin_port
));
737 head
= &sctp_ep_hashtable
[hash
];
738 read_lock(&head
->lock
);
739 for (epb
= head
->chain
; epb
; epb
= epb
->next
) {
741 if (sctp_endpoint_is_match(ep
, laddr
))
745 ep
= sctp_sk((sctp_get_ctl_sock()))->ep
;
749 sctp_endpoint_hold(ep
);
750 read_unlock(&head
->lock
);
754 /* Insert association into the hash table. */
755 static void __sctp_hash_established(struct sctp_association
*asoc
)
757 struct sctp_ep_common
**epp
;
758 struct sctp_ep_common
*epb
;
759 struct sctp_hashbucket
*head
;
763 /* Calculate which chain this entry will belong to. */
764 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
, asoc
->peer
.port
);
766 head
= &sctp_assoc_hashtable
[epb
->hashent
];
768 sctp_write_lock(&head
->lock
);
772 (*epp
)->pprev
= &epb
->next
;
775 sctp_write_unlock(&head
->lock
);
778 /* Add an association to the hash. Local BH-safe. */
779 void sctp_hash_established(struct sctp_association
*asoc
)
784 sctp_local_bh_disable();
785 __sctp_hash_established(asoc
);
786 sctp_local_bh_enable();
789 /* Remove association from the hash table. */
790 static void __sctp_unhash_established(struct sctp_association
*asoc
)
792 struct sctp_hashbucket
*head
;
793 struct sctp_ep_common
*epb
;
797 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
,
800 head
= &sctp_assoc_hashtable
[epb
->hashent
];
802 sctp_write_lock(&head
->lock
);
806 epb
->next
->pprev
= epb
->pprev
;
807 *epb
->pprev
= epb
->next
;
811 sctp_write_unlock(&head
->lock
);
814 /* Remove association from the hash table. Local BH-safe. */
815 void sctp_unhash_established(struct sctp_association
*asoc
)
820 sctp_local_bh_disable();
821 __sctp_unhash_established(asoc
);
822 sctp_local_bh_enable();
825 /* Look up an association. */
826 static struct sctp_association
*__sctp_lookup_association(
827 const union sctp_addr
*local
,
828 const union sctp_addr
*peer
,
829 struct sctp_transport
**pt
)
831 struct sctp_hashbucket
*head
;
832 struct sctp_ep_common
*epb
;
833 struct sctp_association
*asoc
;
834 struct sctp_transport
*transport
;
837 /* Optimize here for direct hit, only listening connections can
838 * have wildcards anyways.
840 hash
= sctp_assoc_hashfn(ntohs(local
->v4
.sin_port
), ntohs(peer
->v4
.sin_port
));
841 head
= &sctp_assoc_hashtable
[hash
];
842 read_lock(&head
->lock
);
843 for (epb
= head
->chain
; epb
; epb
= epb
->next
) {
844 asoc
= sctp_assoc(epb
);
845 transport
= sctp_assoc_is_match(asoc
, local
, peer
);
850 read_unlock(&head
->lock
);
856 sctp_association_hold(asoc
);
857 read_unlock(&head
->lock
);
861 /* Look up an association. BH-safe. */
863 struct sctp_association
*sctp_lookup_association(const union sctp_addr
*laddr
,
864 const union sctp_addr
*paddr
,
865 struct sctp_transport
**transportp
)
867 struct sctp_association
*asoc
;
869 sctp_local_bh_disable();
870 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
871 sctp_local_bh_enable();
876 /* Is there an association matching the given local and peer addresses? */
877 int sctp_has_association(const union sctp_addr
*laddr
,
878 const union sctp_addr
*paddr
)
880 struct sctp_association
*asoc
;
881 struct sctp_transport
*transport
;
882 union sctp_addr tmp
, tmp2
;
883 flip_to_n(&tmp
, laddr
);
884 flip_to_n(&tmp2
, paddr
);
886 if ((asoc
= sctp_lookup_association(&tmp
, &tmp2
, &transport
))) {
887 sctp_association_put(asoc
);
895 * SCTP Implementors Guide, 2.18 Handling of address
896 * parameters within the INIT or INIT-ACK.
898 * D) When searching for a matching TCB upon reception of an INIT
899 * or INIT-ACK chunk the receiver SHOULD use not only the
900 * source address of the packet (containing the INIT or
901 * INIT-ACK) but the receiver SHOULD also use all valid
902 * address parameters contained within the chunk.
904 * 2.18.3 Solution description
906 * This new text clearly specifies to an implementor the need
907 * to look within the INIT or INIT-ACK. Any implementation that
908 * does not do this, may not be able to establish associations
909 * in certain circumstances.
912 static struct sctp_association
*__sctp_rcv_init_lookup(struct sk_buff
*skb
,
913 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
915 struct sctp_association
*asoc
;
916 union sctp_addr addr
;
917 union sctp_addr
*paddr
= &addr
;
918 struct sctphdr
*sh
= (struct sctphdr
*) skb
->h
.raw
;
920 union sctp_params params
;
921 sctp_init_chunk_t
*init
;
922 struct sctp_transport
*transport
;
924 union sctp_addr tmp2
;
926 ch
= (sctp_chunkhdr_t
*) skb
->data
;
928 /* If this is INIT/INIT-ACK look inside the chunk too. */
931 case SCTP_CID_INIT_ACK
:
937 /* The code below will attempt to walk the chunk and extract
938 * parameter information. Before we do that, we need to verify
939 * that the chunk length doesn't cause overflow. Otherwise, we'll
942 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
946 * This code will NOT touch anything inside the chunk--it is
947 * strictly READ-ONLY.
949 * RFC 2960 3 SCTP packet Format
951 * Multiple chunks can be bundled into one SCTP packet up to
952 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
953 * COMPLETE chunks. These chunks MUST NOT be bundled with any
954 * other chunk in a packet. See Section 6.10 for more details
958 /* Find the start of the TLVs and the end of the chunk. This is
959 * the region we search for address parameters.
961 init
= (sctp_init_chunk_t
*)skb
->data
;
963 /* Walk the parameters looking for embedded addresses. */
964 sctp_walk_params(params
, init
, init_hdr
.params
) {
966 /* Note: Ignoring hostname addresses. */
967 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
971 af
->from_addr_param(paddr
, params
.addr
, ntohs(sh
->source
), 0);
972 flip_to_n(&tmp2
, paddr
);
974 asoc
= __sctp_lookup_association(laddr
, &tmp2
, &transport
);
982 /* Lookup an association for an inbound skb. */
983 static struct sctp_association
*__sctp_rcv_lookup(struct sk_buff
*skb
,
984 const union sctp_addr
*paddr
,
985 const union sctp_addr
*laddr
,
986 struct sctp_transport
**transportp
)
988 struct sctp_association
*asoc
;
990 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
992 /* Further lookup for INIT/INIT-ACK packets.
993 * SCTP Implementors Guide, 2.18 Handling of address
994 * parameters within the INIT or INIT-ACK.
997 asoc
= __sctp_rcv_init_lookup(skb
, laddr
, transportp
);