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
;
133 if (skb
->pkt_type
!=PACKET_HOST
)
136 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS
);
138 sh
= (struct sctphdr
*) skb
->h
.raw
;
140 /* Pull up the IP and SCTP headers. */
141 __skb_pull(skb
, skb
->h
.raw
- skb
->data
);
142 if (skb
->len
< sizeof(struct sctphdr
))
144 if ((skb
->ip_summed
!= CHECKSUM_UNNECESSARY
) &&
145 (sctp_rcv_checksum(skb
) < 0))
148 skb_pull(skb
, sizeof(struct sctphdr
));
150 /* Make sure we at least have chunk headers worth of data left. */
151 if (skb
->len
< sizeof(struct sctp_chunkhdr
))
154 family
= ipver2af(skb
->nh
.iph
->version
);
155 af
= sctp_get_af_specific(family
);
159 /* Initialize local addresses for lookups. */
160 af
->from_skb(&src
, skb
, 1);
161 af
->from_skb(&dest
, skb
, 0);
163 /* If the packet is to or from a non-unicast address,
164 * silently discard the packet.
166 * This is not clearly defined in the RFC except in section
167 * 8.4 - OOTB handling. However, based on the book "Stream Control
168 * Transmission Protocol" 2.1, "It is important to note that the
169 * IP address of an SCTP transport address must be a routable
170 * unicast address. In other words, IP multicast addresses and
171 * IP broadcast addresses cannot be used in an SCTP transport
174 if (!af
->addr_valid(&src
, NULL
, skb
) ||
175 !af
->addr_valid(&dest
, NULL
, skb
))
178 asoc
= __sctp_rcv_lookup(skb
, &src
, &dest
, &transport
);
181 ep
= __sctp_rcv_lookup_endpoint(&dest
);
183 /* Retrieve the common input handling substructure. */
184 rcvr
= asoc
? &asoc
->base
: &ep
->base
;
188 * If a frame arrives on an interface and the receiving socket is
189 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
191 if (sk
->sk_bound_dev_if
&& (sk
->sk_bound_dev_if
!= af
->skb_iif(skb
)))
194 sctp_association_put(asoc
);
197 sctp_endpoint_put(ep
);
200 sk
= sctp_get_ctl_sock();
201 ep
= sctp_sk(sk
)->ep
;
202 sctp_endpoint_hold(ep
);
207 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
208 * An SCTP packet is called an "out of the blue" (OOTB)
209 * packet if it is correctly formed, i.e., passed the
210 * receiver's checksum check, but the receiver is not
211 * able to identify the association to which this
215 if (sctp_rcv_ootb(skb
)) {
216 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES
);
217 goto discard_release
;
221 /* SCTP seems to always need a timestamp right now (FIXME) */
222 if (skb
->tstamp
.off_sec
== 0) {
223 __net_timestamp(skb
);
224 sock_enable_timestamp(sk
);
227 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
228 goto discard_release
;
231 if (sk_filter(sk
, skb
))
232 goto discard_release
;
234 /* Create an SCTP packet structure. */
235 chunk
= sctp_chunkify(skb
, asoc
, sk
);
237 goto discard_release
;
238 SCTP_INPUT_CB(skb
)->chunk
= chunk
;
240 /* Remember what endpoint is to handle this packet. */
243 /* Remember the SCTP header. */
244 chunk
->sctp_hdr
= sh
;
246 /* Set the source and destination addresses of the incoming chunk. */
247 sctp_init_addrs(chunk
, &src
, &dest
);
249 /* Remember where we came from. */
250 chunk
->transport
= transport
;
252 /* Acquire access to the sock lock. Note: We are safe from other
253 * bottom halves on this lock, but a user may be in the lock too,
254 * so check if it is busy.
256 sctp_bh_lock_sock(sk
);
258 if (sock_owned_by_user(sk
)) {
259 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG
);
260 sctp_add_backlog(sk
, skb
);
262 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ
);
263 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. */
270 sctp_association_put(asoc
);
272 sctp_endpoint_put(ep
);
277 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS
);
282 /* Release the asoc/ep ref we took in the lookup calls. */
284 sctp_association_put(asoc
);
286 sctp_endpoint_put(ep
);
291 /* Process the backlog queue of the socket. Every skb on
292 * the backlog holds a ref on an association or endpoint.
293 * We hold this ref throughout the state machine to make
294 * sure that the structure we need is still around.
296 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
298 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
299 struct sctp_inq
*inqueue
= &chunk
->rcvr
->inqueue
;
300 struct sctp_ep_common
*rcvr
= NULL
;
305 /* If the rcvr is dead then the association or endpoint
306 * has been deleted and we can safely drop the chunk
307 * and refs that we are holding.
310 sctp_chunk_free(chunk
);
314 if (unlikely(rcvr
->sk
!= sk
)) {
315 /* In this case, the association moved from one socket to
316 * another. We are currently sitting on the backlog of the
317 * old socket, so we need to move.
318 * However, since we are here in the process context we
319 * need to take make sure that the user doesn't own
320 * the new socket when we process the packet.
321 * If the new socket is user-owned, queue the chunk to the
322 * backlog of the new socket without dropping any refs.
323 * Otherwise, we can safely push the chunk on the inqueue.
327 sctp_bh_lock_sock(sk
);
329 if (sock_owned_by_user(sk
)) {
330 sk_add_backlog(sk
, skb
);
333 sctp_inq_push(inqueue
, chunk
);
335 sctp_bh_unlock_sock(sk
);
337 /* If the chunk was backloged again, don't drop refs */
341 sctp_inq_push(inqueue
, chunk
);
345 /* Release the refs we took in sctp_add_backlog */
346 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
347 sctp_association_put(sctp_assoc(rcvr
));
348 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
349 sctp_endpoint_put(sctp_ep(rcvr
));
356 static void sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
358 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
359 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
361 /* Hold the assoc/ep while hanging on the backlog queue.
362 * This way, we know structures we need will not disappear from us
364 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
365 sctp_association_hold(sctp_assoc(rcvr
));
366 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
367 sctp_endpoint_hold(sctp_ep(rcvr
));
371 sk_add_backlog(sk
, skb
);
374 /* Handle icmp frag needed error. */
375 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
376 struct sctp_transport
*t
, __u32 pmtu
)
378 if (sock_owned_by_user(sk
) || !t
|| (t
->pathmtu
== pmtu
))
381 if (t
->param_flags
& SPP_PMTUD_ENABLE
) {
382 if (unlikely(pmtu
< SCTP_DEFAULT_MINSEGMENT
)) {
383 printk(KERN_WARNING
"%s: Reported pmtu %d too low, "
384 "using default minimum of %d\n",
386 SCTP_DEFAULT_MINSEGMENT
);
387 /* Use default minimum segment size and disable
388 * pmtu discovery on this transport.
390 t
->pathmtu
= SCTP_DEFAULT_MINSEGMENT
;
391 t
->param_flags
= (t
->param_flags
& ~SPP_HB
) |
397 /* Update association pmtu. */
398 sctp_assoc_sync_pmtu(asoc
);
401 /* Retransmit with the new pmtu setting.
402 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
403 * Needed will never be sent, but if a message was sent before
404 * PMTU discovery was disabled that was larger than the PMTU, it
405 * would not be fragmented, so it must be re-transmitted fragmented.
407 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
411 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
413 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
414 * or a "Protocol Unreachable" treat this message as an abort
415 * with the T bit set.
417 * This function sends an event to the state machine, which will abort the
421 void sctp_icmp_proto_unreachable(struct sock
*sk
,
422 struct sctp_association
*asoc
,
423 struct sctp_transport
*t
)
425 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__
);
427 sctp_do_sm(SCTP_EVENT_T_OTHER
,
428 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
429 asoc
->state
, asoc
->ep
, asoc
, t
,
434 /* Common lookup code for icmp/icmpv6 error handler. */
435 struct sock
*sctp_err_lookup(int family
, struct sk_buff
*skb
,
436 struct sctphdr
*sctphdr
,
437 struct sctp_association
**app
,
438 struct sctp_transport
**tpp
)
440 union sctp_addr saddr
;
441 union sctp_addr daddr
;
443 struct sock
*sk
= NULL
;
444 struct sctp_association
*asoc
;
445 struct sctp_transport
*transport
= NULL
;
447 *app
= NULL
; *tpp
= NULL
;
449 af
= sctp_get_af_specific(family
);
454 /* Initialize local addresses for lookups. */
455 af
->from_skb(&saddr
, skb
, 1);
456 af
->from_skb(&daddr
, skb
, 0);
458 /* Look for an association that matches the incoming ICMP error
461 asoc
= __sctp_lookup_association(&saddr
, &daddr
, &transport
);
467 if (ntohl(sctphdr
->vtag
) != asoc
->c
.peer_vtag
) {
468 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
472 sctp_bh_lock_sock(sk
);
474 /* If too many ICMPs get dropped on busy
475 * servers this needs to be solved differently.
477 if (sock_owned_by_user(sk
))
478 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS
);
486 sctp_association_put(asoc
);
490 /* Common cleanup code for icmp/icmpv6 error handler. */
491 void sctp_err_finish(struct sock
*sk
, struct sctp_association
*asoc
)
493 sctp_bh_unlock_sock(sk
);
495 sctp_association_put(asoc
);
499 * This routine is called by the ICMP module when it gets some
500 * sort of error condition. If err < 0 then the socket should
501 * be closed and the error returned to the user. If err > 0
502 * it's just the icmp type << 8 | icmp code. After adjustment
503 * header points to the first 8 bytes of the sctp header. We need
504 * to find the appropriate port.
506 * The locking strategy used here is very "optimistic". When
507 * someone else accesses the socket the ICMP is just dropped
508 * and for some paths there is no check at all.
509 * A more general error queue to queue errors for later handling
510 * is probably better.
513 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
515 struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
516 struct sctphdr
*sh
= (struct sctphdr
*)(skb
->data
+ (iph
->ihl
<<2));
517 int type
= skb
->h
.icmph
->type
;
518 int code
= skb
->h
.icmph
->code
;
520 struct sctp_association
*asoc
= NULL
;
521 struct sctp_transport
*transport
;
522 struct inet_sock
*inet
;
523 char *saveip
, *savesctp
;
526 if (skb
->len
< ((iph
->ihl
<< 2) + 8)) {
527 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
531 /* Fix up skb to look at the embedded net header. */
532 saveip
= skb
->nh
.raw
;
533 savesctp
= skb
->h
.raw
;
535 skb
->h
.raw
= (char *)sh
;
536 sk
= sctp_err_lookup(AF_INET
, skb
, sh
, &asoc
, &transport
);
537 /* Put back, the original pointers. */
538 skb
->nh
.raw
= saveip
;
539 skb
->h
.raw
= savesctp
;
541 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
544 /* Warning: The sock lock is held. Remember to call
549 case ICMP_PARAMETERPROB
:
552 case ICMP_DEST_UNREACH
:
553 if (code
> NR_ICMP_UNREACH
)
556 /* PMTU discovery (RFC1191) */
557 if (ICMP_FRAG_NEEDED
== code
) {
558 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
562 if (ICMP_PROT_UNREACH
== code
) {
563 sctp_icmp_proto_unreachable(sk
, asoc
,
568 err
= icmp_err_convert
[code
].errno
;
570 case ICMP_TIME_EXCEEDED
:
571 /* Ignore any time exceeded errors due to fragment reassembly
574 if (ICMP_EXC_FRAGTIME
== code
)
584 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
586 sk
->sk_error_report(sk
);
587 } else { /* Only an error on timeout */
588 sk
->sk_err_soft
= err
;
592 sctp_err_finish(sk
, asoc
);
596 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
598 * This function scans all the chunks in the OOTB packet to determine if
599 * the packet should be discarded right away. If a response might be needed
600 * for this packet, or, if further processing is possible, the packet will
601 * be queued to a proper inqueue for the next phase of handling.
604 * Return 0 - If further processing is needed.
605 * Return 1 - If the packet can be discarded right away.
607 int sctp_rcv_ootb(struct sk_buff
*skb
)
613 ch
= (sctp_chunkhdr_t
*) skb
->data
;
615 /* Scan through all the chunks in the packet. */
617 /* Break out if chunk length is less then minimal. */
618 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
621 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
622 if (ch_end
> skb
->tail
)
625 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
626 * receiver MUST silently discard the OOTB packet and take no
629 if (SCTP_CID_ABORT
== ch
->type
)
632 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
633 * chunk, the receiver should silently discard the packet
634 * and take no further action.
636 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
639 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
640 * or a COOKIE ACK the SCTP Packet should be silently
643 if (SCTP_CID_COOKIE_ACK
== ch
->type
)
646 if (SCTP_CID_ERROR
== ch
->type
) {
647 sctp_walk_errors(err
, ch
) {
648 if (SCTP_ERROR_STALE_COOKIE
== err
->cause
)
653 ch
= (sctp_chunkhdr_t
*) ch_end
;
654 } while (ch_end
< skb
->tail
);
662 /* Insert endpoint into the hash table. */
663 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
665 struct sctp_ep_common
**epp
;
666 struct sctp_ep_common
*epb
;
667 struct sctp_hashbucket
*head
;
671 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
672 head
= &sctp_ep_hashtable
[epb
->hashent
];
674 sctp_write_lock(&head
->lock
);
678 (*epp
)->pprev
= &epb
->next
;
681 sctp_write_unlock(&head
->lock
);
684 /* Add an endpoint to the hash. Local BH-safe. */
685 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
687 sctp_local_bh_disable();
688 __sctp_hash_endpoint(ep
);
689 sctp_local_bh_enable();
692 /* Remove endpoint from the hash table. */
693 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
695 struct sctp_hashbucket
*head
;
696 struct sctp_ep_common
*epb
;
700 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
702 head
= &sctp_ep_hashtable
[epb
->hashent
];
704 sctp_write_lock(&head
->lock
);
708 epb
->next
->pprev
= epb
->pprev
;
709 *epb
->pprev
= epb
->next
;
713 sctp_write_unlock(&head
->lock
);
716 /* Remove endpoint from the hash. Local BH-safe. */
717 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
719 sctp_local_bh_disable();
720 __sctp_unhash_endpoint(ep
);
721 sctp_local_bh_enable();
724 /* Look up an endpoint. */
725 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(const union sctp_addr
*laddr
)
727 struct sctp_hashbucket
*head
;
728 struct sctp_ep_common
*epb
;
729 struct sctp_endpoint
*ep
;
732 hash
= sctp_ep_hashfn(laddr
->v4
.sin_port
);
733 head
= &sctp_ep_hashtable
[hash
];
734 read_lock(&head
->lock
);
735 for (epb
= head
->chain
; epb
; epb
= epb
->next
) {
737 if (sctp_endpoint_is_match(ep
, laddr
))
741 ep
= sctp_sk((sctp_get_ctl_sock()))->ep
;
745 sctp_endpoint_hold(ep
);
746 read_unlock(&head
->lock
);
750 /* Insert association into the hash table. */
751 static void __sctp_hash_established(struct sctp_association
*asoc
)
753 struct sctp_ep_common
**epp
;
754 struct sctp_ep_common
*epb
;
755 struct sctp_hashbucket
*head
;
759 /* Calculate which chain this entry will belong to. */
760 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
, asoc
->peer
.port
);
762 head
= &sctp_assoc_hashtable
[epb
->hashent
];
764 sctp_write_lock(&head
->lock
);
768 (*epp
)->pprev
= &epb
->next
;
771 sctp_write_unlock(&head
->lock
);
774 /* Add an association to the hash. Local BH-safe. */
775 void sctp_hash_established(struct sctp_association
*asoc
)
777 sctp_local_bh_disable();
778 __sctp_hash_established(asoc
);
779 sctp_local_bh_enable();
782 /* Remove association from the hash table. */
783 static void __sctp_unhash_established(struct sctp_association
*asoc
)
785 struct sctp_hashbucket
*head
;
786 struct sctp_ep_common
*epb
;
790 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
,
793 head
= &sctp_assoc_hashtable
[epb
->hashent
];
795 sctp_write_lock(&head
->lock
);
799 epb
->next
->pprev
= epb
->pprev
;
800 *epb
->pprev
= epb
->next
;
804 sctp_write_unlock(&head
->lock
);
807 /* Remove association from the hash table. Local BH-safe. */
808 void sctp_unhash_established(struct sctp_association
*asoc
)
810 sctp_local_bh_disable();
811 __sctp_unhash_established(asoc
);
812 sctp_local_bh_enable();
815 /* Look up an association. */
816 static struct sctp_association
*__sctp_lookup_association(
817 const union sctp_addr
*local
,
818 const union sctp_addr
*peer
,
819 struct sctp_transport
**pt
)
821 struct sctp_hashbucket
*head
;
822 struct sctp_ep_common
*epb
;
823 struct sctp_association
*asoc
;
824 struct sctp_transport
*transport
;
827 /* Optimize here for direct hit, only listening connections can
828 * have wildcards anyways.
830 hash
= sctp_assoc_hashfn(local
->v4
.sin_port
, peer
->v4
.sin_port
);
831 head
= &sctp_assoc_hashtable
[hash
];
832 read_lock(&head
->lock
);
833 for (epb
= head
->chain
; epb
; epb
= epb
->next
) {
834 asoc
= sctp_assoc(epb
);
835 transport
= sctp_assoc_is_match(asoc
, local
, peer
);
840 read_unlock(&head
->lock
);
846 sctp_association_hold(asoc
);
847 read_unlock(&head
->lock
);
851 /* Look up an association. BH-safe. */
853 struct sctp_association
*sctp_lookup_association(const union sctp_addr
*laddr
,
854 const union sctp_addr
*paddr
,
855 struct sctp_transport
**transportp
)
857 struct sctp_association
*asoc
;
859 sctp_local_bh_disable();
860 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
861 sctp_local_bh_enable();
866 /* Is there an association matching the given local and peer addresses? */
867 int sctp_has_association(const union sctp_addr
*laddr
,
868 const union sctp_addr
*paddr
)
870 struct sctp_association
*asoc
;
871 struct sctp_transport
*transport
;
873 if ((asoc
= sctp_lookup_association(laddr
, paddr
, &transport
))) {
874 sctp_association_put(asoc
);
882 * SCTP Implementors Guide, 2.18 Handling of address
883 * parameters within the INIT or INIT-ACK.
885 * D) When searching for a matching TCB upon reception of an INIT
886 * or INIT-ACK chunk the receiver SHOULD use not only the
887 * source address of the packet (containing the INIT or
888 * INIT-ACK) but the receiver SHOULD also use all valid
889 * address parameters contained within the chunk.
891 * 2.18.3 Solution description
893 * This new text clearly specifies to an implementor the need
894 * to look within the INIT or INIT-ACK. Any implementation that
895 * does not do this, may not be able to establish associations
896 * in certain circumstances.
899 static struct sctp_association
*__sctp_rcv_init_lookup(struct sk_buff
*skb
,
900 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
902 struct sctp_association
*asoc
;
903 union sctp_addr addr
;
904 union sctp_addr
*paddr
= &addr
;
905 struct sctphdr
*sh
= (struct sctphdr
*) skb
->h
.raw
;
907 union sctp_params params
;
908 sctp_init_chunk_t
*init
;
909 struct sctp_transport
*transport
;
912 ch
= (sctp_chunkhdr_t
*) skb
->data
;
914 /* If this is INIT/INIT-ACK look inside the chunk too. */
917 case SCTP_CID_INIT_ACK
:
923 /* The code below will attempt to walk the chunk and extract
924 * parameter information. Before we do that, we need to verify
925 * that the chunk length doesn't cause overflow. Otherwise, we'll
928 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
932 * This code will NOT touch anything inside the chunk--it is
933 * strictly READ-ONLY.
935 * RFC 2960 3 SCTP packet Format
937 * Multiple chunks can be bundled into one SCTP packet up to
938 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
939 * COMPLETE chunks. These chunks MUST NOT be bundled with any
940 * other chunk in a packet. See Section 6.10 for more details
944 /* Find the start of the TLVs and the end of the chunk. This is
945 * the region we search for address parameters.
947 init
= (sctp_init_chunk_t
*)skb
->data
;
949 /* Walk the parameters looking for embedded addresses. */
950 sctp_walk_params(params
, init
, init_hdr
.params
) {
952 /* Note: Ignoring hostname addresses. */
953 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
957 af
->from_addr_param(paddr
, params
.addr
, ntohs(sh
->source
), 0);
959 asoc
= __sctp_lookup_association(laddr
, paddr
, &transport
);
967 /* Lookup an association for an inbound skb. */
968 static struct sctp_association
*__sctp_rcv_lookup(struct sk_buff
*skb
,
969 const union sctp_addr
*paddr
,
970 const union sctp_addr
*laddr
,
971 struct sctp_transport
**transportp
)
973 struct sctp_association
*asoc
;
975 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
977 /* Further lookup for INIT/INIT-ACK packets.
978 * SCTP Implementors Guide, 2.18 Handling of address
979 * parameters within the INIT or INIT-ACK.
982 asoc
= __sctp_rcv_init_lookup(skb
, laddr
, transportp
);