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
)
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
));
87 for (; list
; list
= list
->next
)
88 val
= sctp_update_cksum((__u8
*)list
->data
, skb_headlen(list
),
91 val
= sctp_end_cksum(val
);
94 /* CRC failure, dump it. */
95 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS
);
101 struct sctp_input_cb
{
103 struct inet_skb_parm h4
;
104 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
105 struct inet6_skb_parm h6
;
108 struct sctp_chunk
*chunk
;
110 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
113 * This is the routine which IP calls when receiving an SCTP packet.
115 int sctp_rcv(struct sk_buff
*skb
)
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
;
125 union sctp_addr dest
;
129 if (skb
->pkt_type
!=PACKET_HOST
)
132 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS
);
134 if (skb_linearize(skb
))
139 /* Pull up the IP and SCTP headers. */
140 __skb_pull(skb
, skb_transport_offset(skb
));
141 if (skb
->len
< sizeof(struct sctphdr
))
143 if ((skb
->ip_summed
!= CHECKSUM_UNNECESSARY
) &&
144 (sctp_rcv_checksum(skb
) < 0))
147 skb_pull(skb
, sizeof(struct sctphdr
));
149 /* Make sure we at least have chunk headers worth of data left. */
150 if (skb
->len
< sizeof(struct sctp_chunkhdr
))
153 family
= ipver2af(ip_hdr(skb
)->version
);
154 af
= sctp_get_af_specific(family
);
158 /* Initialize local addresses for lookups. */
159 af
->from_skb(&src
, skb
, 1);
160 af
->from_skb(&dest
, skb
, 0);
162 /* If the packet is to or from a non-unicast address,
163 * silently discard the packet.
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
173 if (!af
->addr_valid(&src
, NULL
, skb
) ||
174 !af
->addr_valid(&dest
, NULL
, skb
))
177 asoc
= __sctp_rcv_lookup(skb
, &src
, &dest
, &transport
);
180 ep
= __sctp_rcv_lookup_endpoint(&dest
);
182 /* Retrieve the common input handling substructure. */
183 rcvr
= asoc
? &asoc
->base
: &ep
->base
;
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
190 if (sk
->sk_bound_dev_if
&& (sk
->sk_bound_dev_if
!= af
->skb_iif(skb
)))
193 sctp_association_put(asoc
);
196 sctp_endpoint_put(ep
);
199 sk
= sctp_get_ctl_sock();
200 ep
= sctp_sk(sk
)->ep
;
201 sctp_endpoint_hold(ep
);
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
214 if (sctp_rcv_ootb(skb
)) {
215 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES
);
216 goto discard_release
;
220 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
221 goto discard_release
;
224 if (sk_filter(sk
, skb
))
225 goto discard_release
;
227 /* Create an SCTP packet structure. */
228 chunk
= sctp_chunkify(skb
, asoc
, sk
);
230 goto discard_release
;
231 SCTP_INPUT_CB(skb
)->chunk
= chunk
;
233 /* Remember what endpoint is to handle this packet. */
236 /* Remember the SCTP header. */
237 chunk
->sctp_hdr
= sh
;
239 /* Set the source and destination addresses of the incoming chunk. */
240 sctp_init_addrs(chunk
, &src
, &dest
);
242 /* Remember where we came from. */
243 chunk
->transport
= transport
;
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.
249 sctp_bh_lock_sock(sk
);
251 if (sock_owned_by_user(sk
)) {
252 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG
);
253 sctp_add_backlog(sk
, skb
);
255 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ
);
256 sctp_inq_push(&chunk
->rcvr
->inqueue
, chunk
);
259 sctp_bh_unlock_sock(sk
);
261 /* Release the asoc/ep ref we took in the lookup calls. */
263 sctp_association_put(asoc
);
265 sctp_endpoint_put(ep
);
270 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS
);
275 /* Release the asoc/ep ref we took in the lookup calls. */
277 sctp_association_put(asoc
);
279 sctp_endpoint_put(ep
);
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.
289 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
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
;
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.
303 sctp_chunk_free(chunk
);
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.
320 sctp_bh_lock_sock(sk
);
322 if (sock_owned_by_user(sk
)) {
323 sk_add_backlog(sk
, skb
);
326 sctp_inq_push(inqueue
, chunk
);
328 sctp_bh_unlock_sock(sk
);
330 /* If the chunk was backloged again, don't drop refs */
334 sctp_inq_push(inqueue
, chunk
);
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
));
349 static void sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
351 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
352 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
354 /* Hold the assoc/ep while hanging on the backlog queue.
355 * This way, we know structures we need will not disappear from us
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
));
364 sk_add_backlog(sk
, skb
);
367 /* Handle icmp frag needed error. */
368 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
369 struct sctp_transport
*t
, __u32 pmtu
)
371 if (sock_owned_by_user(sk
) || !t
|| (t
->pathmtu
== pmtu
))
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",
379 SCTP_DEFAULT_MINSEGMENT
);
380 /* Use default minimum segment size and disable
381 * pmtu discovery on this transport.
383 t
->pathmtu
= SCTP_DEFAULT_MINSEGMENT
;
384 t
->param_flags
= (t
->param_flags
& ~SPP_PMTUD
) |
390 /* Update association pmtu. */
391 sctp_assoc_sync_pmtu(asoc
);
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.
400 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
404 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
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.
410 * This function sends an event to the state machine, which will abort the
414 void sctp_icmp_proto_unreachable(struct sock
*sk
,
415 struct sctp_association
*asoc
,
416 struct sctp_transport
*t
)
418 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__
);
420 sctp_do_sm(SCTP_EVENT_T_OTHER
,
421 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
422 asoc
->state
, asoc
->ep
, asoc
, t
,
427 /* Common lookup code for icmp/icmpv6 error handler. */
428 struct sock
*sctp_err_lookup(int family
, struct sk_buff
*skb
,
429 struct sctphdr
*sctphdr
,
430 struct sctp_association
**app
,
431 struct sctp_transport
**tpp
)
433 union sctp_addr saddr
;
434 union sctp_addr daddr
;
436 struct sock
*sk
= NULL
;
437 struct sctp_association
*asoc
;
438 struct sctp_transport
*transport
= NULL
;
440 *app
= NULL
; *tpp
= NULL
;
442 af
= sctp_get_af_specific(family
);
447 /* Initialize local addresses for lookups. */
448 af
->from_skb(&saddr
, skb
, 1);
449 af
->from_skb(&daddr
, skb
, 0);
451 /* Look for an association that matches the incoming ICMP error
454 asoc
= __sctp_lookup_association(&saddr
, &daddr
, &transport
);
460 if (ntohl(sctphdr
->vtag
) != asoc
->c
.peer_vtag
) {
461 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
465 sctp_bh_lock_sock(sk
);
467 /* If too many ICMPs get dropped on busy
468 * servers this needs to be solved differently.
470 if (sock_owned_by_user(sk
))
471 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS
);
479 sctp_association_put(asoc
);
483 /* Common cleanup code for icmp/icmpv6 error handler. */
484 void sctp_err_finish(struct sock
*sk
, struct sctp_association
*asoc
)
486 sctp_bh_unlock_sock(sk
);
488 sctp_association_put(asoc
);
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.
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.
506 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
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
;
513 struct sctp_association
*asoc
= NULL
;
514 struct sctp_transport
*transport
;
515 struct inet_sock
*inet
;
516 sk_buff_data_t saveip
, savesctp
;
519 if (skb
->len
< ihlen
+ 8) {
520 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
524 /* Fix up skb to look at the embedded net header. */
525 saveip
= skb
->network_header
;
526 savesctp
= skb
->transport_header
;
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 values. */
531 skb
->network_header
= saveip
;
532 skb
->transport_header
= savesctp
;
534 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
537 /* Warning: The sock lock is held. Remember to call
542 case ICMP_PARAMETERPROB
:
545 case ICMP_DEST_UNREACH
:
546 if (code
> NR_ICMP_UNREACH
)
549 /* PMTU discovery (RFC1191) */
550 if (ICMP_FRAG_NEEDED
== code
) {
551 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
555 if (ICMP_PROT_UNREACH
== code
) {
556 sctp_icmp_proto_unreachable(sk
, asoc
,
561 err
= icmp_err_convert
[code
].errno
;
563 case ICMP_TIME_EXCEEDED
:
564 /* Ignore any time exceeded errors due to fragment reassembly
567 if (ICMP_EXC_FRAGTIME
== code
)
577 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
579 sk
->sk_error_report(sk
);
580 } else { /* Only an error on timeout */
581 sk
->sk_err_soft
= err
;
585 sctp_err_finish(sk
, asoc
);
589 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
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.
597 * Return 0 - If further processing is needed.
598 * Return 1 - If the packet can be discarded right away.
600 int sctp_rcv_ootb(struct sk_buff
*skb
)
606 ch
= (sctp_chunkhdr_t
*) skb
->data
;
608 /* Scan through all the chunks in the packet. */
610 /* Break out if chunk length is less then minimal. */
611 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
614 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
615 if (ch_end
> skb_tail_pointer(skb
))
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
622 if (SCTP_CID_ABORT
== ch
->type
)
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.
629 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
632 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
633 * or a COOKIE ACK the SCTP Packet should be silently
636 if (SCTP_CID_COOKIE_ACK
== ch
->type
)
639 if (SCTP_CID_ERROR
== ch
->type
) {
640 sctp_walk_errors(err
, ch
) {
641 if (SCTP_ERROR_STALE_COOKIE
== err
->cause
)
646 ch
= (sctp_chunkhdr_t
*) ch_end
;
647 } while (ch_end
< skb_tail_pointer(skb
));
655 /* Insert endpoint into the hash table. */
656 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
658 struct sctp_ep_common
**epp
;
659 struct sctp_ep_common
*epb
;
660 struct sctp_hashbucket
*head
;
664 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
665 head
= &sctp_ep_hashtable
[epb
->hashent
];
667 sctp_write_lock(&head
->lock
);
671 (*epp
)->pprev
= &epb
->next
;
674 sctp_write_unlock(&head
->lock
);
677 /* Add an endpoint to the hash. Local BH-safe. */
678 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
680 sctp_local_bh_disable();
681 __sctp_hash_endpoint(ep
);
682 sctp_local_bh_enable();
685 /* Remove endpoint from the hash table. */
686 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
688 struct sctp_hashbucket
*head
;
689 struct sctp_ep_common
*epb
;
693 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
695 head
= &sctp_ep_hashtable
[epb
->hashent
];
697 sctp_write_lock(&head
->lock
);
701 epb
->next
->pprev
= epb
->pprev
;
702 *epb
->pprev
= epb
->next
;
706 sctp_write_unlock(&head
->lock
);
709 /* Remove endpoint from the hash. Local BH-safe. */
710 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
712 sctp_local_bh_disable();
713 __sctp_unhash_endpoint(ep
);
714 sctp_local_bh_enable();
717 /* Look up an endpoint. */
718 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(const union sctp_addr
*laddr
)
720 struct sctp_hashbucket
*head
;
721 struct sctp_ep_common
*epb
;
722 struct sctp_endpoint
*ep
;
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
) {
730 if (sctp_endpoint_is_match(ep
, laddr
))
734 ep
= sctp_sk((sctp_get_ctl_sock()))->ep
;
738 sctp_endpoint_hold(ep
);
739 read_unlock(&head
->lock
);
743 /* Insert association into the hash table. */
744 static void __sctp_hash_established(struct sctp_association
*asoc
)
746 struct sctp_ep_common
**epp
;
747 struct sctp_ep_common
*epb
;
748 struct sctp_hashbucket
*head
;
752 /* Calculate which chain this entry will belong to. */
753 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
, asoc
->peer
.port
);
755 head
= &sctp_assoc_hashtable
[epb
->hashent
];
757 sctp_write_lock(&head
->lock
);
761 (*epp
)->pprev
= &epb
->next
;
764 sctp_write_unlock(&head
->lock
);
767 /* Add an association to the hash. Local BH-safe. */
768 void sctp_hash_established(struct sctp_association
*asoc
)
773 sctp_local_bh_disable();
774 __sctp_hash_established(asoc
);
775 sctp_local_bh_enable();
778 /* Remove association from the hash table. */
779 static void __sctp_unhash_established(struct sctp_association
*asoc
)
781 struct sctp_hashbucket
*head
;
782 struct sctp_ep_common
*epb
;
786 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
,
789 head
= &sctp_assoc_hashtable
[epb
->hashent
];
791 sctp_write_lock(&head
->lock
);
795 epb
->next
->pprev
= epb
->pprev
;
796 *epb
->pprev
= epb
->next
;
800 sctp_write_unlock(&head
->lock
);
803 /* Remove association from the hash table. Local BH-safe. */
804 void sctp_unhash_established(struct sctp_association
*asoc
)
809 sctp_local_bh_disable();
810 __sctp_unhash_established(asoc
);
811 sctp_local_bh_enable();
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
)
820 struct sctp_hashbucket
*head
;
821 struct sctp_ep_common
*epb
;
822 struct sctp_association
*asoc
;
823 struct sctp_transport
*transport
;
826 /* Optimize here for direct hit, only listening connections can
827 * have wildcards anyways.
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
);
839 read_unlock(&head
->lock
);
845 sctp_association_hold(asoc
);
846 read_unlock(&head
->lock
);
850 /* Look up an association. BH-safe. */
852 struct sctp_association
*sctp_lookup_association(const union sctp_addr
*laddr
,
853 const union sctp_addr
*paddr
,
854 struct sctp_transport
**transportp
)
856 struct sctp_association
*asoc
;
858 sctp_local_bh_disable();
859 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
860 sctp_local_bh_enable();
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
)
869 struct sctp_association
*asoc
;
870 struct sctp_transport
*transport
;
872 if ((asoc
= sctp_lookup_association(laddr
, paddr
, &transport
))) {
873 sctp_association_put(asoc
);
881 * SCTP Implementors Guide, 2.18 Handling of address
882 * parameters within the INIT or INIT-ACK.
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.
890 * 2.18.3 Solution description
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.
898 static struct sctp_association
*__sctp_rcv_init_lookup(struct sk_buff
*skb
,
899 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
901 struct sctp_association
*asoc
;
902 union sctp_addr addr
;
903 union sctp_addr
*paddr
= &addr
;
904 struct sctphdr
*sh
= sctp_hdr(skb
);
906 union sctp_params params
;
907 sctp_init_chunk_t
*init
;
908 struct sctp_transport
*transport
;
911 ch
= (sctp_chunkhdr_t
*) skb
->data
;
913 /* If this is INIT/INIT-ACK look inside the chunk too. */
916 case SCTP_CID_INIT_ACK
:
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
927 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
931 * This code will NOT touch anything inside the chunk--it is
932 * strictly READ-ONLY.
934 * RFC 2960 3 SCTP packet Format
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
943 /* Find the start of the TLVs and the end of the chunk. This is
944 * the region we search for address parameters.
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
));
956 af
->from_addr_param(paddr
, params
.addr
, sh
->source
, 0);
958 asoc
= __sctp_lookup_association(laddr
, paddr
, &transport
);
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
)
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.
981 asoc
= __sctp_rcv_init_lookup(skb
, laddr
, transportp
);