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
);
77 /* Calculate the SCTP checksum of an SCTP packet. */
78 static inline int sctp_rcv_checksum(struct sk_buff
*skb
)
82 struct sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
84 sh
= (struct sctphdr
*) skb
->h
.raw
;
85 cmp
= ntohl(sh
->checksum
);
87 val
= sctp_start_cksum((__u8
*)sh
, skb_headlen(skb
));
89 for (; list
; list
= list
->next
)
90 val
= sctp_update_cksum((__u8
*)list
->data
, skb_headlen(list
),
93 val
= sctp_end_cksum(val
);
96 /* CRC failure, dump it. */
97 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS
);
103 /* The free routine for skbuffs that sctp receives */
104 static void sctp_rfree(struct sk_buff
*skb
)
106 atomic_sub(sizeof(struct sctp_chunk
),&skb
->sk
->sk_rmem_alloc
);
110 /* The ownership wrapper routine to do receive buffer accounting */
111 static void sctp_rcv_set_owner_r(struct sk_buff
*skb
, struct sock
*sk
)
113 skb_set_owner_r(skb
,sk
);
114 skb
->destructor
= sctp_rfree
;
115 atomic_add(sizeof(struct sctp_chunk
),&sk
->sk_rmem_alloc
);
119 * This is the routine which IP calls when receiving an SCTP packet.
121 int sctp_rcv(struct sk_buff
*skb
)
124 struct sctp_association
*asoc
;
125 struct sctp_endpoint
*ep
= NULL
;
126 struct sctp_ep_common
*rcvr
;
127 struct sctp_transport
*transport
= NULL
;
128 struct sctp_chunk
*chunk
;
131 union sctp_addr dest
;
136 if (skb
->pkt_type
!=PACKET_HOST
)
139 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS
);
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
))
147 if (sctp_rcv_checksum(skb
) < 0)
150 skb_pull(skb
, sizeof(struct sctphdr
));
152 /* Make sure we at least have chunk headers worth of data left. */
153 if (skb
->len
< sizeof(struct sctp_chunkhdr
))
156 family
= ipver2af(skb
->nh
.iph
->version
);
157 af
= sctp_get_af_specific(family
);
161 /* Initialize local addresses for lookups. */
162 af
->from_skb(&src
, skb
, 1);
163 af
->from_skb(&dest
, skb
, 0);
165 /* If the packet is to or from a non-unicast address,
166 * silently discard the packet.
168 * This is not clearly defined in the RFC except in section
169 * 8.4 - OOTB handling. However, based on the book "Stream Control
170 * Transmission Protocol" 2.1, "It is important to note that the
171 * IP address of an SCTP transport address must be a routable
172 * unicast address. In other words, IP multicast addresses and
173 * IP broadcast addresses cannot be used in an SCTP transport
176 if (!af
->addr_valid(&src
, NULL
) || !af
->addr_valid(&dest
, NULL
))
179 asoc
= __sctp_rcv_lookup(skb
, &src
, &dest
, &transport
);
182 ep
= __sctp_rcv_lookup_endpoint(&dest
);
184 /* Retrieve the common input handling substructure. */
185 rcvr
= asoc
? &asoc
->base
: &ep
->base
;
189 * If a frame arrives on an interface and the receiving socket is
190 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
192 if (sk
->sk_bound_dev_if
&& (sk
->sk_bound_dev_if
!= af
->skb_iif(skb
)))
196 sctp_association_put(asoc
);
199 sctp_endpoint_put(ep
);
202 sk
= sctp_get_ctl_sock();
203 ep
= sctp_sk(sk
)->ep
;
204 sctp_endpoint_hold(ep
);
209 if (atomic_read(&sk
->sk_rmem_alloc
) >= sk
->sk_rcvbuf
)
210 goto discard_release
;
213 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
214 * An SCTP packet is called an "out of the blue" (OOTB)
215 * packet if it is correctly formed, i.e., passed the
216 * receiver's checksum check, but the receiver is not
217 * able to identify the association to which this
221 if (sctp_rcv_ootb(skb
)) {
222 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES
);
223 goto discard_release
;
227 /* SCTP seems to always need a timestamp right now (FIXME) */
228 if (skb
->stamp
.tv_sec
== 0) {
229 do_gettimeofday(&skb
->stamp
);
230 sock_enable_timestamp(sk
);
233 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
234 goto discard_release
;
236 ret
= sk_filter(sk
, skb
, 1);
238 goto discard_release
;
240 /* Create an SCTP packet structure. */
241 chunk
= sctp_chunkify(skb
, asoc
, sk
);
244 goto discard_release
;
247 sctp_rcv_set_owner_r(skb
,sk
);
249 /* Remember what endpoint is to handle this packet. */
252 /* Remember the SCTP header. */
253 chunk
->sctp_hdr
= sh
;
255 /* Set the source and destination addresses of the incoming chunk. */
256 sctp_init_addrs(chunk
, &src
, &dest
);
258 /* Remember where we came from. */
259 chunk
->transport
= transport
;
261 /* Acquire access to the sock lock. Note: We are safe from other
262 * bottom halves on this lock, but a user may be in the lock too,
263 * so check if it is busy.
265 sctp_bh_lock_sock(sk
);
267 if (sock_owned_by_user(sk
))
268 sk_add_backlog(sk
, (struct sk_buff
*) chunk
);
270 sctp_backlog_rcv(sk
, (struct sk_buff
*) chunk
);
272 /* Release the sock and any reference counts we took in the
275 sctp_bh_unlock_sock(sk
);
277 sctp_association_put(asoc
);
279 sctp_endpoint_put(ep
);
288 /* Release any structures we may be holding. */
291 sctp_association_put(asoc
);
293 sctp_endpoint_put(ep
);
298 /* Handle second half of inbound skb processing. If the sock was busy,
299 * we may have need to delay processing until later when the sock is
300 * released (on the backlog). If not busy, we call this routine
301 * directly from the bottom half.
303 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
305 struct sctp_chunk
*chunk
;
306 struct sctp_inq
*inqueue
;
308 /* One day chunk will live inside the skb, but for
311 chunk
= (struct sctp_chunk
*) skb
;
312 inqueue
= &chunk
->rcvr
->inqueue
;
314 sctp_inq_push(inqueue
, chunk
);
318 /* Handle icmp frag needed error. */
319 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
320 struct sctp_transport
*t
, __u32 pmtu
)
322 if (unlikely(pmtu
< SCTP_DEFAULT_MINSEGMENT
)) {
323 printk(KERN_WARNING
"%s: Reported pmtu %d too low, "
324 "using default minimum of %d\n", __FUNCTION__
, pmtu
,
325 SCTP_DEFAULT_MINSEGMENT
);
326 pmtu
= SCTP_DEFAULT_MINSEGMENT
;
329 if (!sock_owned_by_user(sk
) && t
&& (t
->pmtu
!= pmtu
)) {
331 sctp_assoc_sync_pmtu(asoc
);
332 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
337 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
339 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
340 * or a "Protocol Unreachable" treat this message as an abort
341 * with the T bit set.
343 * This function sends an event to the state machine, which will abort the
347 void sctp_icmp_proto_unreachable(struct sock
*sk
,
348 struct sctp_endpoint
*ep
,
349 struct sctp_association
*asoc
,
350 struct sctp_transport
*t
)
352 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__
);
354 sctp_do_sm(SCTP_EVENT_T_OTHER
,
355 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
356 asoc
->state
, asoc
->ep
, asoc
, t
,
361 /* Common lookup code for icmp/icmpv6 error handler. */
362 struct sock
*sctp_err_lookup(int family
, struct sk_buff
*skb
,
363 struct sctphdr
*sctphdr
,
364 struct sctp_endpoint
**epp
,
365 struct sctp_association
**app
,
366 struct sctp_transport
**tpp
)
368 union sctp_addr saddr
;
369 union sctp_addr daddr
;
371 struct sock
*sk
= NULL
;
372 struct sctp_endpoint
*ep
= NULL
;
373 struct sctp_association
*asoc
= NULL
;
374 struct sctp_transport
*transport
= NULL
;
376 *app
= NULL
; *epp
= NULL
; *tpp
= NULL
;
378 af
= sctp_get_af_specific(family
);
383 /* Initialize local addresses for lookups. */
384 af
->from_skb(&saddr
, skb
, 1);
385 af
->from_skb(&daddr
, skb
, 0);
387 /* Look for an association that matches the incoming ICMP error
390 asoc
= __sctp_lookup_association(&saddr
, &daddr
, &transport
);
392 /* If there is no matching association, see if it matches any
393 * endpoint. This may happen for an ICMP error generated in
394 * response to an INIT_ACK.
396 ep
= __sctp_rcv_lookup_endpoint(&daddr
);
405 if (ntohl(sctphdr
->vtag
) != asoc
->c
.peer_vtag
) {
406 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
412 sctp_bh_lock_sock(sk
);
414 /* If too many ICMPs get dropped on busy
415 * servers this needs to be solved differently.
417 if (sock_owned_by_user(sk
))
418 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS
);
428 sctp_association_put(asoc
);
430 sctp_endpoint_put(ep
);
434 /* Common cleanup code for icmp/icmpv6 error handler. */
435 void sctp_err_finish(struct sock
*sk
, struct sctp_endpoint
*ep
,
436 struct sctp_association
*asoc
)
438 sctp_bh_unlock_sock(sk
);
441 sctp_association_put(asoc
);
443 sctp_endpoint_put(ep
);
447 * This routine is called by the ICMP module when it gets some
448 * sort of error condition. If err < 0 then the socket should
449 * be closed and the error returned to the user. If err > 0
450 * it's just the icmp type << 8 | icmp code. After adjustment
451 * header points to the first 8 bytes of the sctp header. We need
452 * to find the appropriate port.
454 * The locking strategy used here is very "optimistic". When
455 * someone else accesses the socket the ICMP is just dropped
456 * and for some paths there is no check at all.
457 * A more general error queue to queue errors for later handling
458 * is probably better.
461 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
463 struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
464 struct sctphdr
*sh
= (struct sctphdr
*)(skb
->data
+ (iph
->ihl
<<2));
465 int type
= skb
->h
.icmph
->type
;
466 int code
= skb
->h
.icmph
->code
;
468 struct sctp_endpoint
*ep
;
469 struct sctp_association
*asoc
;
470 struct sctp_transport
*transport
;
471 struct inet_sock
*inet
;
472 char *saveip
, *savesctp
;
475 if (skb
->len
< ((iph
->ihl
<< 2) + 8)) {
476 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
480 /* Fix up skb to look at the embedded net header. */
481 saveip
= skb
->nh
.raw
;
482 savesctp
= skb
->h
.raw
;
484 skb
->h
.raw
= (char *)sh
;
485 sk
= sctp_err_lookup(AF_INET
, skb
, sh
, &ep
, &asoc
, &transport
);
486 /* Put back, the original pointers. */
487 skb
->nh
.raw
= saveip
;
488 skb
->h
.raw
= savesctp
;
490 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS
);
493 /* Warning: The sock lock is held. Remember to call
498 case ICMP_PARAMETERPROB
:
501 case ICMP_DEST_UNREACH
:
502 if (code
> NR_ICMP_UNREACH
)
505 /* PMTU discovery (RFC1191) */
506 if (ICMP_FRAG_NEEDED
== code
) {
507 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
511 if (ICMP_PROT_UNREACH
== code
) {
512 sctp_icmp_proto_unreachable(sk
, ep
, asoc
,
517 err
= icmp_err_convert
[code
].errno
;
519 case ICMP_TIME_EXCEEDED
:
520 /* Ignore any time exceeded errors due to fragment reassembly
523 if (ICMP_EXC_FRAGTIME
== code
)
533 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
535 sk
->sk_error_report(sk
);
536 } else { /* Only an error on timeout */
537 sk
->sk_err_soft
= err
;
541 sctp_err_finish(sk
, ep
, asoc
);
545 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
547 * This function scans all the chunks in the OOTB packet to determine if
548 * the packet should be discarded right away. If a response might be needed
549 * for this packet, or, if further processing is possible, the packet will
550 * be queued to a proper inqueue for the next phase of handling.
553 * Return 0 - If further processing is needed.
554 * Return 1 - If the packet can be discarded right away.
556 int sctp_rcv_ootb(struct sk_buff
*skb
)
562 ch
= (sctp_chunkhdr_t
*) skb
->data
;
563 ch_end
= ((__u8
*) ch
) + WORD_ROUND(ntohs(ch
->length
));
565 /* Scan through all the chunks in the packet. */
566 while (ch_end
> (__u8
*)ch
&& ch_end
< skb
->tail
) {
568 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
569 * receiver MUST silently discard the OOTB packet and take no
572 if (SCTP_CID_ABORT
== ch
->type
)
575 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
576 * chunk, the receiver should silently discard the packet
577 * and take no further action.
579 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
582 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
583 * or a COOKIE ACK the SCTP Packet should be silently
586 if (SCTP_CID_COOKIE_ACK
== ch
->type
)
589 if (SCTP_CID_ERROR
== ch
->type
) {
590 sctp_walk_errors(err
, ch
) {
591 if (SCTP_ERROR_STALE_COOKIE
== err
->cause
)
596 ch
= (sctp_chunkhdr_t
*) ch_end
;
597 ch_end
= ((__u8
*) ch
) + WORD_ROUND(ntohs(ch
->length
));
606 /* Insert endpoint into the hash table. */
607 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
609 struct sctp_ep_common
**epp
;
610 struct sctp_ep_common
*epb
;
611 struct sctp_hashbucket
*head
;
615 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
616 head
= &sctp_ep_hashtable
[epb
->hashent
];
618 sctp_write_lock(&head
->lock
);
622 (*epp
)->pprev
= &epb
->next
;
625 sctp_write_unlock(&head
->lock
);
628 /* Add an endpoint to the hash. Local BH-safe. */
629 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
631 sctp_local_bh_disable();
632 __sctp_hash_endpoint(ep
);
633 sctp_local_bh_enable();
636 /* Remove endpoint from the hash table. */
637 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
639 struct sctp_hashbucket
*head
;
640 struct sctp_ep_common
*epb
;
644 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
646 head
= &sctp_ep_hashtable
[epb
->hashent
];
648 sctp_write_lock(&head
->lock
);
652 epb
->next
->pprev
= epb
->pprev
;
653 *epb
->pprev
= epb
->next
;
657 sctp_write_unlock(&head
->lock
);
660 /* Remove endpoint from the hash. Local BH-safe. */
661 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
663 sctp_local_bh_disable();
664 __sctp_unhash_endpoint(ep
);
665 sctp_local_bh_enable();
668 /* Look up an endpoint. */
669 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(const union sctp_addr
*laddr
)
671 struct sctp_hashbucket
*head
;
672 struct sctp_ep_common
*epb
;
673 struct sctp_endpoint
*ep
;
676 hash
= sctp_ep_hashfn(laddr
->v4
.sin_port
);
677 head
= &sctp_ep_hashtable
[hash
];
678 read_lock(&head
->lock
);
679 for (epb
= head
->chain
; epb
; epb
= epb
->next
) {
681 if (sctp_endpoint_is_match(ep
, laddr
))
685 ep
= sctp_sk((sctp_get_ctl_sock()))->ep
;
689 sctp_endpoint_hold(ep
);
691 read_unlock(&head
->lock
);
695 /* Insert association into the hash table. */
696 static void __sctp_hash_established(struct sctp_association
*asoc
)
698 struct sctp_ep_common
**epp
;
699 struct sctp_ep_common
*epb
;
700 struct sctp_hashbucket
*head
;
704 /* Calculate which chain this entry will belong to. */
705 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
, asoc
->peer
.port
);
707 head
= &sctp_assoc_hashtable
[epb
->hashent
];
709 sctp_write_lock(&head
->lock
);
713 (*epp
)->pprev
= &epb
->next
;
716 sctp_write_unlock(&head
->lock
);
719 /* Add an association to the hash. Local BH-safe. */
720 void sctp_hash_established(struct sctp_association
*asoc
)
722 sctp_local_bh_disable();
723 __sctp_hash_established(asoc
);
724 sctp_local_bh_enable();
727 /* Remove association from the hash table. */
728 static void __sctp_unhash_established(struct sctp_association
*asoc
)
730 struct sctp_hashbucket
*head
;
731 struct sctp_ep_common
*epb
;
735 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
,
738 head
= &sctp_assoc_hashtable
[epb
->hashent
];
740 sctp_write_lock(&head
->lock
);
744 epb
->next
->pprev
= epb
->pprev
;
745 *epb
->pprev
= epb
->next
;
749 sctp_write_unlock(&head
->lock
);
752 /* Remove association from the hash table. Local BH-safe. */
753 void sctp_unhash_established(struct sctp_association
*asoc
)
755 sctp_local_bh_disable();
756 __sctp_unhash_established(asoc
);
757 sctp_local_bh_enable();
760 /* Look up an association. */
761 static struct sctp_association
*__sctp_lookup_association(
762 const union sctp_addr
*local
,
763 const union sctp_addr
*peer
,
764 struct sctp_transport
**pt
)
766 struct sctp_hashbucket
*head
;
767 struct sctp_ep_common
*epb
;
768 struct sctp_association
*asoc
;
769 struct sctp_transport
*transport
;
772 /* Optimize here for direct hit, only listening connections can
773 * have wildcards anyways.
775 hash
= sctp_assoc_hashfn(local
->v4
.sin_port
, peer
->v4
.sin_port
);
776 head
= &sctp_assoc_hashtable
[hash
];
777 read_lock(&head
->lock
);
778 for (epb
= head
->chain
; epb
; epb
= epb
->next
) {
779 asoc
= sctp_assoc(epb
);
780 transport
= sctp_assoc_is_match(asoc
, local
, peer
);
785 read_unlock(&head
->lock
);
791 sctp_association_hold(asoc
);
793 read_unlock(&head
->lock
);
797 /* Look up an association. BH-safe. */
799 struct sctp_association
*sctp_lookup_association(const union sctp_addr
*laddr
,
800 const union sctp_addr
*paddr
,
801 struct sctp_transport
**transportp
)
803 struct sctp_association
*asoc
;
805 sctp_local_bh_disable();
806 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
807 sctp_local_bh_enable();
812 /* Is there an association matching the given local and peer addresses? */
813 int sctp_has_association(const union sctp_addr
*laddr
,
814 const union sctp_addr
*paddr
)
816 struct sctp_association
*asoc
;
817 struct sctp_transport
*transport
;
819 if ((asoc
= sctp_lookup_association(laddr
, paddr
, &transport
))) {
820 sock_put(asoc
->base
.sk
);
821 sctp_association_put(asoc
);
829 * SCTP Implementors Guide, 2.18 Handling of address
830 * parameters within the INIT or INIT-ACK.
832 * D) When searching for a matching TCB upon reception of an INIT
833 * or INIT-ACK chunk the receiver SHOULD use not only the
834 * source address of the packet (containing the INIT or
835 * INIT-ACK) but the receiver SHOULD also use all valid
836 * address parameters contained within the chunk.
838 * 2.18.3 Solution description
840 * This new text clearly specifies to an implementor the need
841 * to look within the INIT or INIT-ACK. Any implementation that
842 * does not do this, may not be able to establish associations
843 * in certain circumstances.
846 static struct sctp_association
*__sctp_rcv_init_lookup(struct sk_buff
*skb
,
847 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
849 struct sctp_association
*asoc
;
850 union sctp_addr addr
;
851 union sctp_addr
*paddr
= &addr
;
852 struct sctphdr
*sh
= (struct sctphdr
*) skb
->h
.raw
;
854 union sctp_params params
;
855 sctp_init_chunk_t
*init
;
856 struct sctp_transport
*transport
;
859 ch
= (sctp_chunkhdr_t
*) skb
->data
;
861 /* If this is INIT/INIT-ACK look inside the chunk too. */
864 case SCTP_CID_INIT_ACK
:
870 /* The code below will attempt to walk the chunk and extract
871 * parameter information. Before we do that, we need to verify
872 * that the chunk length doesn't cause overflow. Otherwise, we'll
875 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
879 * This code will NOT touch anything inside the chunk--it is
880 * strictly READ-ONLY.
882 * RFC 2960 3 SCTP packet Format
884 * Multiple chunks can be bundled into one SCTP packet up to
885 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
886 * COMPLETE chunks. These chunks MUST NOT be bundled with any
887 * other chunk in a packet. See Section 6.10 for more details
891 /* Find the start of the TLVs and the end of the chunk. This is
892 * the region we search for address parameters.
894 init
= (sctp_init_chunk_t
*)skb
->data
;
896 /* Walk the parameters looking for embedded addresses. */
897 sctp_walk_params(params
, init
, init_hdr
.params
) {
899 /* Note: Ignoring hostname addresses. */
900 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
904 af
->from_addr_param(paddr
, params
.addr
, ntohs(sh
->source
), 0);
906 asoc
= __sctp_lookup_association(laddr
, paddr
, &transport
);
914 /* Lookup an association for an inbound skb. */
915 static struct sctp_association
*__sctp_rcv_lookup(struct sk_buff
*skb
,
916 const union sctp_addr
*paddr
,
917 const union sctp_addr
*laddr
,
918 struct sctp_transport
**transportp
)
920 struct sctp_association
*asoc
;
922 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
924 /* Further lookup for INIT/INIT-ACK packets.
925 * SCTP Implementors Guide, 2.18 Handling of address
926 * parameters within the INIT or INIT-ACK.
929 asoc
= __sctp_rcv_init_lookup(skb
, laddr
, transportp
);