1 /* SCTP kernel 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 implementation
11 * These functions handle all input from the IP layer into SCTP.
13 * This SCTP 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 * This SCTP 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>
63 #include <net/sctp/checksum.h>
64 #include <net/net_namespace.h>
66 /* Forward declarations for internal helpers. */
67 static int sctp_rcv_ootb(struct sk_buff
*);
68 static struct sctp_association
*__sctp_rcv_lookup(struct sk_buff
*skb
,
69 const union sctp_addr
*laddr
,
70 const union sctp_addr
*paddr
,
71 struct sctp_transport
**transportp
);
72 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(const union sctp_addr
*laddr
);
73 static struct sctp_association
*__sctp_lookup_association(
74 const union sctp_addr
*local
,
75 const union sctp_addr
*peer
,
76 struct sctp_transport
**pt
);
78 static int sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
);
81 /* Calculate the SCTP checksum of an SCTP packet. */
82 static inline int sctp_rcv_checksum(struct sk_buff
*skb
)
84 struct sctphdr
*sh
= sctp_hdr(skb
);
85 __le32 cmp
= sh
->checksum
;
88 __u32 tmp
= sctp_start_cksum((__u8
*)sh
, skb_headlen(skb
));
90 skb_walk_frags(skb
, list
)
91 tmp
= sctp_update_cksum((__u8
*)list
->data
, skb_headlen(list
),
94 val
= sctp_end_cksum(tmp
);
97 /* CRC failure, dump it. */
98 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS
);
104 struct sctp_input_cb
{
106 struct inet_skb_parm h4
;
107 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
108 struct inet6_skb_parm h6
;
111 struct sctp_chunk
*chunk
;
113 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
116 * This is the routine which IP calls when receiving an SCTP packet.
118 int sctp_rcv(struct sk_buff
*skb
)
121 struct sctp_association
*asoc
;
122 struct sctp_endpoint
*ep
= NULL
;
123 struct sctp_ep_common
*rcvr
;
124 struct sctp_transport
*transport
= NULL
;
125 struct sctp_chunk
*chunk
;
128 union sctp_addr dest
;
132 if (skb
->pkt_type
!=PACKET_HOST
)
135 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS
);
137 if (skb_linearize(skb
))
142 /* Pull up the IP and SCTP headers. */
143 __skb_pull(skb
, skb_transport_offset(skb
));
144 if (skb
->len
< sizeof(struct sctphdr
))
146 if (!sctp_checksum_disable
&& !skb_csum_unnecessary(skb
) &&
147 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(ip_hdr(skb
)->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
, skb
) ||
177 !af
->addr_valid(&dest
, NULL
, skb
))
180 asoc
= __sctp_rcv_lookup(skb
, &src
, &dest
, &transport
);
183 ep
= __sctp_rcv_lookup_endpoint(&dest
);
185 /* Retrieve the common input handling substructure. */
186 rcvr
= asoc
? &asoc
->base
: &ep
->base
;
190 * If a frame arrives on an interface and the receiving socket is
191 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
193 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 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
210 * An SCTP packet is called an "out of the blue" (OOTB)
211 * packet if it is correctly formed, i.e., passed the
212 * receiver's checksum check, but the receiver is not
213 * able to identify the association to which this
217 if (sctp_rcv_ootb(skb
)) {
218 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES
);
219 goto discard_release
;
223 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
224 goto discard_release
;
227 if (sk_filter(sk
, skb
))
228 goto discard_release
;
230 /* Create an SCTP packet structure. */
231 chunk
= sctp_chunkify(skb
, asoc
, sk
);
233 goto discard_release
;
234 SCTP_INPUT_CB(skb
)->chunk
= chunk
;
236 /* Remember what endpoint is to handle this packet. */
239 /* Remember the SCTP header. */
240 chunk
->sctp_hdr
= sh
;
242 /* Set the source and destination addresses of the incoming chunk. */
243 sctp_init_addrs(chunk
, &src
, &dest
);
245 /* Remember where we came from. */
246 chunk
->transport
= transport
;
248 /* Acquire access to the sock lock. Note: We are safe from other
249 * bottom halves on this lock, but a user may be in the lock too,
250 * so check if it is busy.
252 sctp_bh_lock_sock(sk
);
254 if (sk
!= rcvr
->sk
) {
255 /* Our cached sk is different from the rcvr->sk. This is
256 * because migrate()/accept() may have moved the association
257 * to a new socket and released all the sockets. So now we
258 * are holding a lock on the old socket while the user may
259 * be doing something with the new socket. Switch our veiw
262 sctp_bh_unlock_sock(sk
);
264 sctp_bh_lock_sock(sk
);
267 if (sock_owned_by_user(sk
)) {
268 if (sctp_add_backlog(sk
, skb
)) {
269 sctp_bh_unlock_sock(sk
);
270 sctp_chunk_free(chunk
);
271 skb
= NULL
; /* sctp_chunk_free already freed the skb */
272 goto discard_release
;
274 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG
);
276 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ
);
277 sctp_inq_push(&chunk
->rcvr
->inqueue
, chunk
);
280 sctp_bh_unlock_sock(sk
);
282 /* Release the asoc/ep ref we took in the lookup calls. */
284 sctp_association_put(asoc
);
286 sctp_endpoint_put(ep
);
291 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS
);
296 /* Release the asoc/ep ref we took in the lookup calls. */
298 sctp_association_put(asoc
);
300 sctp_endpoint_put(ep
);
305 /* Process the backlog queue of the socket. Every skb on
306 * the backlog holds a ref on an association or endpoint.
307 * We hold this ref throughout the state machine to make
308 * sure that the structure we need is still around.
310 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
312 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
313 struct sctp_inq
*inqueue
= &chunk
->rcvr
->inqueue
;
314 struct sctp_ep_common
*rcvr
= NULL
;
319 /* If the rcvr is dead then the association or endpoint
320 * has been deleted and we can safely drop the chunk
321 * and refs that we are holding.
324 sctp_chunk_free(chunk
);
328 if (unlikely(rcvr
->sk
!= sk
)) {
329 /* In this case, the association moved from one socket to
330 * another. We are currently sitting on the backlog of the
331 * old socket, so we need to move.
332 * However, since we are here in the process context we
333 * need to take make sure that the user doesn't own
334 * the new socket when we process the packet.
335 * If the new socket is user-owned, queue the chunk to the
336 * backlog of the new socket without dropping any refs.
337 * Otherwise, we can safely push the chunk on the inqueue.
341 sctp_bh_lock_sock(sk
);
343 if (sock_owned_by_user(sk
)) {
344 if (sk_add_backlog(sk
, skb
))
345 sctp_chunk_free(chunk
);
349 sctp_inq_push(inqueue
, chunk
);
351 sctp_bh_unlock_sock(sk
);
353 /* If the chunk was backloged again, don't drop refs */
357 sctp_inq_push(inqueue
, chunk
);
361 /* Release the refs we took in sctp_add_backlog */
362 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
363 sctp_association_put(sctp_assoc(rcvr
));
364 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
365 sctp_endpoint_put(sctp_ep(rcvr
));
372 static int sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
374 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
375 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
378 ret
= sk_add_backlog(sk
, skb
);
380 /* Hold the assoc/ep while hanging on the backlog queue.
381 * This way, we know structures we need will not disappear
384 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
385 sctp_association_hold(sctp_assoc(rcvr
));
386 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
387 sctp_endpoint_hold(sctp_ep(rcvr
));
395 /* Handle icmp frag needed error. */
396 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
397 struct sctp_transport
*t
, __u32 pmtu
)
399 if (!t
|| (t
->pathmtu
<= pmtu
))
402 if (sock_owned_by_user(sk
)) {
403 asoc
->pmtu_pending
= 1;
408 if (t
->param_flags
& SPP_PMTUD_ENABLE
) {
409 /* Update transports view of the MTU */
410 sctp_transport_update_pmtu(t
, pmtu
);
412 /* Update association pmtu. */
413 sctp_assoc_sync_pmtu(asoc
);
416 /* Retransmit with the new pmtu setting.
417 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
418 * Needed will never be sent, but if a message was sent before
419 * PMTU discovery was disabled that was larger than the PMTU, it
420 * would not be fragmented, so it must be re-transmitted fragmented.
422 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
426 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
428 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
429 * or a "Protocol Unreachable" treat this message as an abort
430 * with the T bit set.
432 * This function sends an event to the state machine, which will abort the
436 void sctp_icmp_proto_unreachable(struct sock
*sk
,
437 struct sctp_association
*asoc
,
438 struct sctp_transport
*t
)
440 SCTP_DEBUG_PRINTK("%s\n", __func__
);
442 if (sock_owned_by_user(sk
)) {
443 if (timer_pending(&t
->proto_unreach_timer
))
446 if (!mod_timer(&t
->proto_unreach_timer
,
448 sctp_association_hold(asoc
);
452 if (timer_pending(&t
->proto_unreach_timer
) &&
453 del_timer(&t
->proto_unreach_timer
))
454 sctp_association_put(asoc
);
456 sctp_do_sm(SCTP_EVENT_T_OTHER
,
457 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
458 asoc
->state
, asoc
->ep
, asoc
, t
,
463 /* Common lookup code for icmp/icmpv6 error handler. */
464 struct sock
*sctp_err_lookup(int family
, struct sk_buff
*skb
,
465 struct sctphdr
*sctphdr
,
466 struct sctp_association
**app
,
467 struct sctp_transport
**tpp
)
469 union sctp_addr saddr
;
470 union sctp_addr daddr
;
472 struct sock
*sk
= NULL
;
473 struct sctp_association
*asoc
;
474 struct sctp_transport
*transport
= NULL
;
475 struct sctp_init_chunk
*chunkhdr
;
476 __u32 vtag
= ntohl(sctphdr
->vtag
);
477 int len
= skb
->len
- ((void *)sctphdr
- (void *)skb
->data
);
479 *app
= NULL
; *tpp
= NULL
;
481 af
= sctp_get_af_specific(family
);
486 /* Initialize local addresses for lookups. */
487 af
->from_skb(&saddr
, skb
, 1);
488 af
->from_skb(&daddr
, skb
, 0);
490 /* Look for an association that matches the incoming ICMP error
493 asoc
= __sctp_lookup_association(&saddr
, &daddr
, &transport
);
499 /* RFC 4960, Appendix C. ICMP Handling
501 * ICMP6) An implementation MUST validate that the Verification Tag
502 * contained in the ICMP message matches the Verification Tag of
503 * the peer. If the Verification Tag is not 0 and does NOT
504 * match, discard the ICMP message. If it is 0 and the ICMP
505 * message contains enough bytes to verify that the chunk type is
506 * an INIT chunk and that the Initiate Tag matches the tag of the
507 * peer, continue with ICMP7. If the ICMP message is too short
508 * or the chunk type or the Initiate Tag does not match, silently
509 * discard the packet.
512 chunkhdr
= (struct sctp_init_chunk
*)((void *)sctphdr
513 + sizeof(struct sctphdr
));
514 if (len
< sizeof(struct sctphdr
) + sizeof(sctp_chunkhdr_t
)
516 chunkhdr
->chunk_hdr
.type
!= SCTP_CID_INIT
||
517 ntohl(chunkhdr
->init_hdr
.init_tag
) != asoc
->c
.my_vtag
) {
520 } else if (vtag
!= asoc
->c
.peer_vtag
) {
524 sctp_bh_lock_sock(sk
);
526 /* If too many ICMPs get dropped on busy
527 * servers this needs to be solved differently.
529 if (sock_owned_by_user(sk
))
530 NET_INC_STATS_BH(&init_net
, LINUX_MIB_LOCKDROPPEDICMPS
);
538 sctp_association_put(asoc
);
542 /* Common cleanup code for icmp/icmpv6 error handler. */
543 void sctp_err_finish(struct sock
*sk
, struct sctp_association
*asoc
)
545 sctp_bh_unlock_sock(sk
);
547 sctp_association_put(asoc
);
551 * This routine is called by the ICMP module when it gets some
552 * sort of error condition. If err < 0 then the socket should
553 * be closed and the error returned to the user. If err > 0
554 * it's just the icmp type << 8 | icmp code. After adjustment
555 * header points to the first 8 bytes of the sctp header. We need
556 * to find the appropriate port.
558 * The locking strategy used here is very "optimistic". When
559 * someone else accesses the socket the ICMP is just dropped
560 * and for some paths there is no check at all.
561 * A more general error queue to queue errors for later handling
562 * is probably better.
565 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
567 struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
568 const int ihlen
= iph
->ihl
* 4;
569 const int type
= icmp_hdr(skb
)->type
;
570 const int code
= icmp_hdr(skb
)->code
;
572 struct sctp_association
*asoc
= NULL
;
573 struct sctp_transport
*transport
;
574 struct inet_sock
*inet
;
575 sk_buff_data_t saveip
, savesctp
;
578 if (skb
->len
< ihlen
+ 8) {
579 ICMP_INC_STATS_BH(&init_net
, ICMP_MIB_INERRORS
);
583 /* Fix up skb to look at the embedded net header. */
584 saveip
= skb
->network_header
;
585 savesctp
= skb
->transport_header
;
586 skb_reset_network_header(skb
);
587 skb_set_transport_header(skb
, ihlen
);
588 sk
= sctp_err_lookup(AF_INET
, skb
, sctp_hdr(skb
), &asoc
, &transport
);
589 /* Put back, the original values. */
590 skb
->network_header
= saveip
;
591 skb
->transport_header
= savesctp
;
593 ICMP_INC_STATS_BH(&init_net
, ICMP_MIB_INERRORS
);
596 /* Warning: The sock lock is held. Remember to call
601 case ICMP_PARAMETERPROB
:
604 case ICMP_DEST_UNREACH
:
605 if (code
> NR_ICMP_UNREACH
)
608 /* PMTU discovery (RFC1191) */
609 if (ICMP_FRAG_NEEDED
== code
) {
610 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
614 if (ICMP_PROT_UNREACH
== code
) {
615 sctp_icmp_proto_unreachable(sk
, asoc
,
620 err
= icmp_err_convert
[code
].errno
;
622 case ICMP_TIME_EXCEEDED
:
623 /* Ignore any time exceeded errors due to fragment reassembly
626 if (ICMP_EXC_FRAGTIME
== code
)
636 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
638 sk
->sk_error_report(sk
);
639 } else { /* Only an error on timeout */
640 sk
->sk_err_soft
= err
;
644 sctp_err_finish(sk
, asoc
);
648 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
650 * This function scans all the chunks in the OOTB packet to determine if
651 * the packet should be discarded right away. If a response might be needed
652 * for this packet, or, if further processing is possible, the packet will
653 * be queued to a proper inqueue for the next phase of handling.
656 * Return 0 - If further processing is needed.
657 * Return 1 - If the packet can be discarded right away.
659 static int sctp_rcv_ootb(struct sk_buff
*skb
)
665 ch
= (sctp_chunkhdr_t
*) skb
->data
;
667 /* Scan through all the chunks in the packet. */
669 /* Break out if chunk length is less then minimal. */
670 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
673 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
674 if (ch_end
> skb_tail_pointer(skb
))
677 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
678 * receiver MUST silently discard the OOTB packet and take no
681 if (SCTP_CID_ABORT
== ch
->type
)
684 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
685 * chunk, the receiver should silently discard the packet
686 * and take no further action.
688 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
692 * This will discard packets with INIT chunk bundled as
693 * subsequent chunks in the packet. When INIT is first,
694 * the normal INIT processing will discard the chunk.
696 if (SCTP_CID_INIT
== ch
->type
&& (void *)ch
!= skb
->data
)
699 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
700 * or a COOKIE ACK the SCTP Packet should be silently
703 if (SCTP_CID_COOKIE_ACK
== ch
->type
)
706 if (SCTP_CID_ERROR
== ch
->type
) {
707 sctp_walk_errors(err
, ch
) {
708 if (SCTP_ERROR_STALE_COOKIE
== err
->cause
)
713 ch
= (sctp_chunkhdr_t
*) ch_end
;
714 } while (ch_end
< skb_tail_pointer(skb
));
722 /* Insert endpoint into the hash table. */
723 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
725 struct sctp_ep_common
*epb
;
726 struct sctp_hashbucket
*head
;
730 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
731 head
= &sctp_ep_hashtable
[epb
->hashent
];
733 sctp_write_lock(&head
->lock
);
734 hlist_add_head(&epb
->node
, &head
->chain
);
735 sctp_write_unlock(&head
->lock
);
738 /* Add an endpoint to the hash. Local BH-safe. */
739 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
741 sctp_local_bh_disable();
742 __sctp_hash_endpoint(ep
);
743 sctp_local_bh_enable();
746 /* Remove endpoint from the hash table. */
747 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
749 struct sctp_hashbucket
*head
;
750 struct sctp_ep_common
*epb
;
754 if (hlist_unhashed(&epb
->node
))
757 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
759 head
= &sctp_ep_hashtable
[epb
->hashent
];
761 sctp_write_lock(&head
->lock
);
762 __hlist_del(&epb
->node
);
763 sctp_write_unlock(&head
->lock
);
766 /* Remove endpoint from the hash. Local BH-safe. */
767 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
769 sctp_local_bh_disable();
770 __sctp_unhash_endpoint(ep
);
771 sctp_local_bh_enable();
774 /* Look up an endpoint. */
775 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(const union sctp_addr
*laddr
)
777 struct sctp_hashbucket
*head
;
778 struct sctp_ep_common
*epb
;
779 struct sctp_endpoint
*ep
;
780 struct hlist_node
*node
;
783 hash
= sctp_ep_hashfn(ntohs(laddr
->v4
.sin_port
));
784 head
= &sctp_ep_hashtable
[hash
];
785 read_lock(&head
->lock
);
786 sctp_for_each_hentry(epb
, node
, &head
->chain
) {
788 if (sctp_endpoint_is_match(ep
, laddr
))
792 ep
= sctp_sk((sctp_get_ctl_sock()))->ep
;
795 sctp_endpoint_hold(ep
);
796 read_unlock(&head
->lock
);
800 /* Insert association into the hash table. */
801 static void __sctp_hash_established(struct sctp_association
*asoc
)
803 struct sctp_ep_common
*epb
;
804 struct sctp_hashbucket
*head
;
808 /* Calculate which chain this entry will belong to. */
809 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
, asoc
->peer
.port
);
811 head
= &sctp_assoc_hashtable
[epb
->hashent
];
813 sctp_write_lock(&head
->lock
);
814 hlist_add_head(&epb
->node
, &head
->chain
);
815 sctp_write_unlock(&head
->lock
);
818 /* Add an association to the hash. Local BH-safe. */
819 void sctp_hash_established(struct sctp_association
*asoc
)
824 sctp_local_bh_disable();
825 __sctp_hash_established(asoc
);
826 sctp_local_bh_enable();
829 /* Remove association from the hash table. */
830 static void __sctp_unhash_established(struct sctp_association
*asoc
)
832 struct sctp_hashbucket
*head
;
833 struct sctp_ep_common
*epb
;
837 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
,
840 head
= &sctp_assoc_hashtable
[epb
->hashent
];
842 sctp_write_lock(&head
->lock
);
843 __hlist_del(&epb
->node
);
844 sctp_write_unlock(&head
->lock
);
847 /* Remove association from the hash table. Local BH-safe. */
848 void sctp_unhash_established(struct sctp_association
*asoc
)
853 sctp_local_bh_disable();
854 __sctp_unhash_established(asoc
);
855 sctp_local_bh_enable();
858 /* Look up an association. */
859 static struct sctp_association
*__sctp_lookup_association(
860 const union sctp_addr
*local
,
861 const union sctp_addr
*peer
,
862 struct sctp_transport
**pt
)
864 struct sctp_hashbucket
*head
;
865 struct sctp_ep_common
*epb
;
866 struct sctp_association
*asoc
;
867 struct sctp_transport
*transport
;
868 struct hlist_node
*node
;
871 /* Optimize here for direct hit, only listening connections can
872 * have wildcards anyways.
874 hash
= sctp_assoc_hashfn(ntohs(local
->v4
.sin_port
), ntohs(peer
->v4
.sin_port
));
875 head
= &sctp_assoc_hashtable
[hash
];
876 read_lock(&head
->lock
);
877 sctp_for_each_hentry(epb
, node
, &head
->chain
) {
878 asoc
= sctp_assoc(epb
);
879 transport
= sctp_assoc_is_match(asoc
, local
, peer
);
884 read_unlock(&head
->lock
);
890 sctp_association_hold(asoc
);
891 read_unlock(&head
->lock
);
895 /* Look up an association. BH-safe. */
897 struct sctp_association
*sctp_lookup_association(const union sctp_addr
*laddr
,
898 const union sctp_addr
*paddr
,
899 struct sctp_transport
**transportp
)
901 struct sctp_association
*asoc
;
903 sctp_local_bh_disable();
904 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
905 sctp_local_bh_enable();
910 /* Is there an association matching the given local and peer addresses? */
911 int sctp_has_association(const union sctp_addr
*laddr
,
912 const union sctp_addr
*paddr
)
914 struct sctp_association
*asoc
;
915 struct sctp_transport
*transport
;
917 if ((asoc
= sctp_lookup_association(laddr
, paddr
, &transport
))) {
918 sctp_association_put(asoc
);
926 * SCTP Implementors Guide, 2.18 Handling of address
927 * parameters within the INIT or INIT-ACK.
929 * D) When searching for a matching TCB upon reception of an INIT
930 * or INIT-ACK chunk the receiver SHOULD use not only the
931 * source address of the packet (containing the INIT or
932 * INIT-ACK) but the receiver SHOULD also use all valid
933 * address parameters contained within the chunk.
935 * 2.18.3 Solution description
937 * This new text clearly specifies to an implementor the need
938 * to look within the INIT or INIT-ACK. Any implementation that
939 * does not do this, may not be able to establish associations
940 * in certain circumstances.
943 static struct sctp_association
*__sctp_rcv_init_lookup(struct sk_buff
*skb
,
944 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
946 struct sctp_association
*asoc
;
947 union sctp_addr addr
;
948 union sctp_addr
*paddr
= &addr
;
949 struct sctphdr
*sh
= sctp_hdr(skb
);
951 union sctp_params params
;
952 sctp_init_chunk_t
*init
;
953 struct sctp_transport
*transport
;
956 ch
= (sctp_chunkhdr_t
*) skb
->data
;
959 * This code will NOT touch anything inside the chunk--it is
960 * strictly READ-ONLY.
962 * RFC 2960 3 SCTP packet Format
964 * Multiple chunks can be bundled into one SCTP packet up to
965 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
966 * COMPLETE chunks. These chunks MUST NOT be bundled with any
967 * other chunk in a packet. See Section 6.10 for more details
971 /* Find the start of the TLVs and the end of the chunk. This is
972 * the region we search for address parameters.
974 init
= (sctp_init_chunk_t
*)skb
->data
;
976 /* Walk the parameters looking for embedded addresses. */
977 sctp_walk_params(params
, init
, init_hdr
.params
) {
979 /* Note: Ignoring hostname addresses. */
980 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
984 af
->from_addr_param(paddr
, params
.addr
, sh
->source
, 0);
986 asoc
= __sctp_lookup_association(laddr
, paddr
, &transport
);
994 /* ADD-IP, Section 5.2
995 * When an endpoint receives an ASCONF Chunk from the remote peer
996 * special procedures may be needed to identify the association the
997 * ASCONF Chunk is associated with. To properly find the association
998 * the following procedures SHOULD be followed:
1000 * D2) If the association is not found, use the address found in the
1001 * Address Parameter TLV combined with the port number found in the
1002 * SCTP common header. If found proceed to rule D4.
1004 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1005 * address found in the ASCONF Address Parameter TLV of each of the
1006 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1008 static struct sctp_association
*__sctp_rcv_asconf_lookup(
1009 sctp_chunkhdr_t
*ch
,
1010 const union sctp_addr
*laddr
,
1012 struct sctp_transport
**transportp
)
1014 sctp_addip_chunk_t
*asconf
= (struct sctp_addip_chunk
*)ch
;
1016 union sctp_addr_param
*param
;
1017 union sctp_addr paddr
;
1019 /* Skip over the ADDIP header and find the Address parameter */
1020 param
= (union sctp_addr_param
*)(asconf
+ 1);
1022 af
= sctp_get_af_specific(param_type2af(param
->v4
.param_hdr
.type
));
1026 af
->from_addr_param(&paddr
, param
, peer_port
, 0);
1028 return __sctp_lookup_association(laddr
, &paddr
, transportp
);
1032 /* SCTP-AUTH, Section 6.3:
1033 * If the receiver does not find a STCB for a packet containing an AUTH
1034 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1035 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1038 * This means that any chunks that can help us identify the association need
1039 * to be looked at to find this assocation.
1041 static struct sctp_association
*__sctp_rcv_walk_lookup(struct sk_buff
*skb
,
1042 const union sctp_addr
*laddr
,
1043 struct sctp_transport
**transportp
)
1045 struct sctp_association
*asoc
= NULL
;
1046 sctp_chunkhdr_t
*ch
;
1048 unsigned int chunk_num
= 1;
1051 /* Walk through the chunks looking for AUTH or ASCONF chunks
1052 * to help us find the association.
1054 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1056 /* Break out if chunk length is less then minimal. */
1057 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
1060 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
1061 if (ch_end
> skb_tail_pointer(skb
))
1066 have_auth
= chunk_num
;
1069 case SCTP_CID_COOKIE_ECHO
:
1070 /* If a packet arrives containing an AUTH chunk as
1071 * a first chunk, a COOKIE-ECHO chunk as the second
1072 * chunk, and possibly more chunks after them, and
1073 * the receiver does not have an STCB for that
1074 * packet, then authentication is based on
1075 * the contents of the COOKIE- ECHO chunk.
1077 if (have_auth
== 1 && chunk_num
== 2)
1081 case SCTP_CID_ASCONF
:
1082 if (have_auth
|| sctp_addip_noauth
)
1083 asoc
= __sctp_rcv_asconf_lookup(ch
, laddr
,
1084 sctp_hdr(skb
)->source
,
1093 ch
= (sctp_chunkhdr_t
*) ch_end
;
1095 } while (ch_end
< skb_tail_pointer(skb
));
1101 * There are circumstances when we need to look inside the SCTP packet
1102 * for information to help us find the association. Examples
1103 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1106 static struct sctp_association
*__sctp_rcv_lookup_harder(struct sk_buff
*skb
,
1107 const union sctp_addr
*laddr
,
1108 struct sctp_transport
**transportp
)
1110 sctp_chunkhdr_t
*ch
;
1112 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1114 /* The code below will attempt to walk the chunk and extract
1115 * parameter information. Before we do that, we need to verify
1116 * that the chunk length doesn't cause overflow. Otherwise, we'll
1119 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
1122 /* If this is INIT/INIT-ACK look inside the chunk too. */
1125 case SCTP_CID_INIT_ACK
:
1126 return __sctp_rcv_init_lookup(skb
, laddr
, transportp
);
1130 return __sctp_rcv_walk_lookup(skb
, laddr
, transportp
);
1138 /* Lookup an association for an inbound skb. */
1139 static struct sctp_association
*__sctp_rcv_lookup(struct sk_buff
*skb
,
1140 const union sctp_addr
*paddr
,
1141 const union sctp_addr
*laddr
,
1142 struct sctp_transport
**transportp
)
1144 struct sctp_association
*asoc
;
1146 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
1148 /* Further lookup for INIT/INIT-ACK packets.
1149 * SCTP Implementors Guide, 2.18 Handling of address
1150 * parameters within the INIT or INIT-ACK.
1153 asoc
= __sctp_rcv_lookup_harder(skb
, laddr
, transportp
);