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 */
56 #include <linux/slab.h>
62 #include <net/sctp/sctp.h>
63 #include <net/sctp/sm.h>
64 #include <net/sctp/checksum.h>
65 #include <net/net_namespace.h>
67 /* Forward declarations for internal helpers. */
68 static int sctp_rcv_ootb(struct sk_buff
*);
69 static struct sctp_association
*__sctp_rcv_lookup(struct net
*net
,
71 const union sctp_addr
*laddr
,
72 const union sctp_addr
*paddr
,
73 struct sctp_transport
**transportp
);
74 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(struct net
*net
,
75 const union sctp_addr
*laddr
);
76 static struct sctp_association
*__sctp_lookup_association(
78 const union sctp_addr
*local
,
79 const union sctp_addr
*peer
,
80 struct sctp_transport
**pt
);
82 static int sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
);
85 /* Calculate the SCTP checksum of an SCTP packet. */
86 static inline int sctp_rcv_checksum(struct net
*net
, struct sk_buff
*skb
)
88 struct sctphdr
*sh
= sctp_hdr(skb
);
89 __le32 cmp
= sh
->checksum
;
92 __u32 tmp
= sctp_start_cksum((__u8
*)sh
, skb_headlen(skb
));
94 skb_walk_frags(skb
, list
)
95 tmp
= sctp_update_cksum((__u8
*)list
->data
, skb_headlen(list
),
98 val
= sctp_end_cksum(tmp
);
101 /* CRC failure, dump it. */
102 SCTP_INC_STATS_BH(net
, SCTP_MIB_CHECKSUMERRORS
);
108 struct sctp_input_cb
{
110 struct inet_skb_parm h4
;
111 #if IS_ENABLED(CONFIG_IPV6)
112 struct inet6_skb_parm h6
;
115 struct sctp_chunk
*chunk
;
117 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
120 * This is the routine which IP calls when receiving an SCTP packet.
122 int sctp_rcv(struct sk_buff
*skb
)
125 struct sctp_association
*asoc
;
126 struct sctp_endpoint
*ep
= NULL
;
127 struct sctp_ep_common
*rcvr
;
128 struct sctp_transport
*transport
= NULL
;
129 struct sctp_chunk
*chunk
;
132 union sctp_addr dest
;
135 struct net
*net
= dev_net(skb
->dev
);
137 if (skb
->pkt_type
!=PACKET_HOST
)
140 SCTP_INC_STATS_BH(net
, SCTP_MIB_INSCTPPACKS
);
142 if (skb_linearize(skb
))
147 /* Pull up the IP and SCTP headers. */
148 __skb_pull(skb
, skb_transport_offset(skb
));
149 if (skb
->len
< sizeof(struct sctphdr
))
151 if (!sctp_checksum_disable
&& !skb_csum_unnecessary(skb
) &&
152 sctp_rcv_checksum(net
, skb
) < 0)
155 skb_pull(skb
, sizeof(struct sctphdr
));
157 /* Make sure we at least have chunk headers worth of data left. */
158 if (skb
->len
< sizeof(struct sctp_chunkhdr
))
161 family
= ipver2af(ip_hdr(skb
)->version
);
162 af
= sctp_get_af_specific(family
);
166 /* Initialize local addresses for lookups. */
167 af
->from_skb(&src
, skb
, 1);
168 af
->from_skb(&dest
, skb
, 0);
170 /* If the packet is to or from a non-unicast address,
171 * silently discard the packet.
173 * This is not clearly defined in the RFC except in section
174 * 8.4 - OOTB handling. However, based on the book "Stream Control
175 * Transmission Protocol" 2.1, "It is important to note that the
176 * IP address of an SCTP transport address must be a routable
177 * unicast address. In other words, IP multicast addresses and
178 * IP broadcast addresses cannot be used in an SCTP transport
181 if (!af
->addr_valid(&src
, NULL
, skb
) ||
182 !af
->addr_valid(&dest
, NULL
, skb
))
185 asoc
= __sctp_rcv_lookup(net
, skb
, &src
, &dest
, &transport
);
188 ep
= __sctp_rcv_lookup_endpoint(net
, &dest
);
190 /* Retrieve the common input handling substructure. */
191 rcvr
= asoc
? &asoc
->base
: &ep
->base
;
195 * If a frame arrives on an interface and the receiving socket is
196 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
198 if (sk
->sk_bound_dev_if
&& (sk
->sk_bound_dev_if
!= af
->skb_iif(skb
)))
201 sctp_association_put(asoc
);
204 sctp_endpoint_put(ep
);
207 sk
= net
->sctp
.ctl_sock
;
208 ep
= sctp_sk(sk
)->ep
;
209 sctp_endpoint_hold(ep
);
214 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
215 * An SCTP packet is called an "out of the blue" (OOTB)
216 * packet if it is correctly formed, i.e., passed the
217 * receiver's checksum check, but the receiver is not
218 * able to identify the association to which this
222 if (sctp_rcv_ootb(skb
)) {
223 SCTP_INC_STATS_BH(net
, SCTP_MIB_OUTOFBLUES
);
224 goto discard_release
;
228 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
229 goto discard_release
;
232 if (sk_filter(sk
, skb
))
233 goto discard_release
;
235 /* Create an SCTP packet structure. */
236 chunk
= sctp_chunkify(skb
, asoc
, sk
);
238 goto discard_release
;
239 SCTP_INPUT_CB(skb
)->chunk
= chunk
;
241 /* Remember what endpoint is to handle this packet. */
244 /* Remember the SCTP header. */
245 chunk
->sctp_hdr
= sh
;
247 /* Set the source and destination addresses of the incoming chunk. */
248 sctp_init_addrs(chunk
, &src
, &dest
);
250 /* Remember where we came from. */
251 chunk
->transport
= transport
;
253 /* Acquire access to the sock lock. Note: We are safe from other
254 * bottom halves on this lock, but a user may be in the lock too,
255 * so check if it is busy.
257 sctp_bh_lock_sock(sk
);
259 if (sk
!= rcvr
->sk
) {
260 /* Our cached sk is different from the rcvr->sk. This is
261 * because migrate()/accept() may have moved the association
262 * to a new socket and released all the sockets. So now we
263 * are holding a lock on the old socket while the user may
264 * be doing something with the new socket. Switch our veiw
267 sctp_bh_unlock_sock(sk
);
269 sctp_bh_lock_sock(sk
);
272 if (sock_owned_by_user(sk
)) {
273 if (sctp_add_backlog(sk
, skb
)) {
274 sctp_bh_unlock_sock(sk
);
275 sctp_chunk_free(chunk
);
276 skb
= NULL
; /* sctp_chunk_free already freed the skb */
277 goto discard_release
;
279 SCTP_INC_STATS_BH(net
, SCTP_MIB_IN_PKT_BACKLOG
);
281 SCTP_INC_STATS_BH(net
, SCTP_MIB_IN_PKT_SOFTIRQ
);
282 sctp_inq_push(&chunk
->rcvr
->inqueue
, chunk
);
285 sctp_bh_unlock_sock(sk
);
287 /* Release the asoc/ep ref we took in the lookup calls. */
289 sctp_association_put(asoc
);
291 sctp_endpoint_put(ep
);
296 SCTP_INC_STATS_BH(net
, SCTP_MIB_IN_PKT_DISCARDS
);
301 /* Release the asoc/ep ref we took in the lookup calls. */
303 sctp_association_put(asoc
);
305 sctp_endpoint_put(ep
);
310 /* Process the backlog queue of the socket. Every skb on
311 * the backlog holds a ref on an association or endpoint.
312 * We hold this ref throughout the state machine to make
313 * sure that the structure we need is still around.
315 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
317 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
318 struct sctp_inq
*inqueue
= &chunk
->rcvr
->inqueue
;
319 struct sctp_ep_common
*rcvr
= NULL
;
324 /* If the rcvr is dead then the association or endpoint
325 * has been deleted and we can safely drop the chunk
326 * and refs that we are holding.
329 sctp_chunk_free(chunk
);
333 if (unlikely(rcvr
->sk
!= sk
)) {
334 /* In this case, the association moved from one socket to
335 * another. We are currently sitting on the backlog of the
336 * old socket, so we need to move.
337 * However, since we are here in the process context we
338 * need to take make sure that the user doesn't own
339 * the new socket when we process the packet.
340 * If the new socket is user-owned, queue the chunk to the
341 * backlog of the new socket without dropping any refs.
342 * Otherwise, we can safely push the chunk on the inqueue.
346 sctp_bh_lock_sock(sk
);
348 if (sock_owned_by_user(sk
)) {
349 if (sk_add_backlog(sk
, skb
, sk
->sk_rcvbuf
))
350 sctp_chunk_free(chunk
);
354 sctp_inq_push(inqueue
, chunk
);
356 sctp_bh_unlock_sock(sk
);
358 /* If the chunk was backloged again, don't drop refs */
362 sctp_inq_push(inqueue
, chunk
);
366 /* Release the refs we took in sctp_add_backlog */
367 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
368 sctp_association_put(sctp_assoc(rcvr
));
369 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
370 sctp_endpoint_put(sctp_ep(rcvr
));
377 static int sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
379 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
380 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
383 ret
= sk_add_backlog(sk
, skb
, sk
->sk_rcvbuf
);
385 /* Hold the assoc/ep while hanging on the backlog queue.
386 * This way, we know structures we need will not disappear
389 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
390 sctp_association_hold(sctp_assoc(rcvr
));
391 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
392 sctp_endpoint_hold(sctp_ep(rcvr
));
400 /* Handle icmp frag needed error. */
401 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
402 struct sctp_transport
*t
, __u32 pmtu
)
404 if (!t
|| (t
->pathmtu
<= pmtu
))
407 if (sock_owned_by_user(sk
)) {
408 asoc
->pmtu_pending
= 1;
413 if (t
->param_flags
& SPP_PMTUD_ENABLE
) {
414 /* Update transports view of the MTU */
415 sctp_transport_update_pmtu(sk
, t
, pmtu
);
417 /* Update association pmtu. */
418 sctp_assoc_sync_pmtu(sk
, asoc
);
421 /* Retransmit with the new pmtu setting.
422 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
423 * Needed will never be sent, but if a message was sent before
424 * PMTU discovery was disabled that was larger than the PMTU, it
425 * would not be fragmented, so it must be re-transmitted fragmented.
427 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
430 void sctp_icmp_redirect(struct sock
*sk
, struct sctp_transport
*t
,
433 struct dst_entry
*dst
;
437 dst
= sctp_transport_dst_check(t
);
439 dst
->ops
->redirect(dst
, sk
, skb
);
443 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
445 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
446 * or a "Protocol Unreachable" treat this message as an abort
447 * with the T bit set.
449 * This function sends an event to the state machine, which will abort the
453 void sctp_icmp_proto_unreachable(struct sock
*sk
,
454 struct sctp_association
*asoc
,
455 struct sctp_transport
*t
)
457 SCTP_DEBUG_PRINTK("%s\n", __func__
);
459 if (sock_owned_by_user(sk
)) {
460 if (timer_pending(&t
->proto_unreach_timer
))
463 if (!mod_timer(&t
->proto_unreach_timer
,
465 sctp_association_hold(asoc
);
469 if (timer_pending(&t
->proto_unreach_timer
) &&
470 del_timer(&t
->proto_unreach_timer
))
471 sctp_association_put(asoc
);
473 sctp_do_sm(SCTP_EVENT_T_OTHER
,
474 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
475 asoc
->state
, asoc
->ep
, asoc
, t
,
480 /* Common lookup code for icmp/icmpv6 error handler. */
481 struct sock
*sctp_err_lookup(struct net
*net
, int family
, struct sk_buff
*skb
,
482 struct sctphdr
*sctphdr
,
483 struct sctp_association
**app
,
484 struct sctp_transport
**tpp
)
486 union sctp_addr saddr
;
487 union sctp_addr daddr
;
489 struct sock
*sk
= NULL
;
490 struct sctp_association
*asoc
;
491 struct sctp_transport
*transport
= NULL
;
492 struct sctp_init_chunk
*chunkhdr
;
493 __u32 vtag
= ntohl(sctphdr
->vtag
);
494 int len
= skb
->len
- ((void *)sctphdr
- (void *)skb
->data
);
496 *app
= NULL
; *tpp
= NULL
;
498 af
= sctp_get_af_specific(family
);
503 /* Initialize local addresses for lookups. */
504 af
->from_skb(&saddr
, skb
, 1);
505 af
->from_skb(&daddr
, skb
, 0);
507 /* Look for an association that matches the incoming ICMP error
510 asoc
= __sctp_lookup_association(net
, &saddr
, &daddr
, &transport
);
516 /* RFC 4960, Appendix C. ICMP Handling
518 * ICMP6) An implementation MUST validate that the Verification Tag
519 * contained in the ICMP message matches the Verification Tag of
520 * the peer. If the Verification Tag is not 0 and does NOT
521 * match, discard the ICMP message. If it is 0 and the ICMP
522 * message contains enough bytes to verify that the chunk type is
523 * an INIT chunk and that the Initiate Tag matches the tag of the
524 * peer, continue with ICMP7. If the ICMP message is too short
525 * or the chunk type or the Initiate Tag does not match, silently
526 * discard the packet.
529 chunkhdr
= (void *)sctphdr
+ sizeof(struct sctphdr
);
530 if (len
< sizeof(struct sctphdr
) + sizeof(sctp_chunkhdr_t
)
532 chunkhdr
->chunk_hdr
.type
!= SCTP_CID_INIT
||
533 ntohl(chunkhdr
->init_hdr
.init_tag
) != asoc
->c
.my_vtag
) {
536 } else if (vtag
!= asoc
->c
.peer_vtag
) {
540 sctp_bh_lock_sock(sk
);
542 /* If too many ICMPs get dropped on busy
543 * servers this needs to be solved differently.
545 if (sock_owned_by_user(sk
))
546 NET_INC_STATS_BH(net
, LINUX_MIB_LOCKDROPPEDICMPS
);
554 sctp_association_put(asoc
);
558 /* Common cleanup code for icmp/icmpv6 error handler. */
559 void sctp_err_finish(struct sock
*sk
, struct sctp_association
*asoc
)
561 sctp_bh_unlock_sock(sk
);
563 sctp_association_put(asoc
);
567 * This routine is called by the ICMP module when it gets some
568 * sort of error condition. If err < 0 then the socket should
569 * be closed and the error returned to the user. If err > 0
570 * it's just the icmp type << 8 | icmp code. After adjustment
571 * header points to the first 8 bytes of the sctp header. We need
572 * to find the appropriate port.
574 * The locking strategy used here is very "optimistic". When
575 * someone else accesses the socket the ICMP is just dropped
576 * and for some paths there is no check at all.
577 * A more general error queue to queue errors for later handling
578 * is probably better.
581 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
583 const struct iphdr
*iph
= (const struct iphdr
*)skb
->data
;
584 const int ihlen
= iph
->ihl
* 4;
585 const int type
= icmp_hdr(skb
)->type
;
586 const int code
= icmp_hdr(skb
)->code
;
588 struct sctp_association
*asoc
= NULL
;
589 struct sctp_transport
*transport
;
590 struct inet_sock
*inet
;
591 sk_buff_data_t saveip
, savesctp
;
593 struct net
*net
= dev_net(skb
->dev
);
595 if (skb
->len
< ihlen
+ 8) {
596 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
600 /* Fix up skb to look at the embedded net header. */
601 saveip
= skb
->network_header
;
602 savesctp
= skb
->transport_header
;
603 skb_reset_network_header(skb
);
604 skb_set_transport_header(skb
, ihlen
);
605 sk
= sctp_err_lookup(net
, AF_INET
, skb
, sctp_hdr(skb
), &asoc
, &transport
);
606 /* Put back, the original values. */
607 skb
->network_header
= saveip
;
608 skb
->transport_header
= savesctp
;
610 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
613 /* Warning: The sock lock is held. Remember to call
618 case ICMP_PARAMETERPROB
:
621 case ICMP_DEST_UNREACH
:
622 if (code
> NR_ICMP_UNREACH
)
625 /* PMTU discovery (RFC1191) */
626 if (ICMP_FRAG_NEEDED
== code
) {
627 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
631 if (ICMP_PROT_UNREACH
== code
) {
632 sctp_icmp_proto_unreachable(sk
, asoc
,
637 err
= icmp_err_convert
[code
].errno
;
639 case ICMP_TIME_EXCEEDED
:
640 /* Ignore any time exceeded errors due to fragment reassembly
643 if (ICMP_EXC_FRAGTIME
== code
)
649 sctp_icmp_redirect(sk
, transport
, skb
);
657 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
659 sk
->sk_error_report(sk
);
660 } else { /* Only an error on timeout */
661 sk
->sk_err_soft
= err
;
665 sctp_err_finish(sk
, asoc
);
669 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
671 * This function scans all the chunks in the OOTB packet to determine if
672 * the packet should be discarded right away. If a response might be needed
673 * for this packet, or, if further processing is possible, the packet will
674 * be queued to a proper inqueue for the next phase of handling.
677 * Return 0 - If further processing is needed.
678 * Return 1 - If the packet can be discarded right away.
680 static int sctp_rcv_ootb(struct sk_buff
*skb
)
685 ch
= (sctp_chunkhdr_t
*) skb
->data
;
687 /* Scan through all the chunks in the packet. */
689 /* Break out if chunk length is less then minimal. */
690 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
693 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
694 if (ch_end
> skb_tail_pointer(skb
))
697 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
698 * receiver MUST silently discard the OOTB packet and take no
701 if (SCTP_CID_ABORT
== ch
->type
)
704 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
705 * chunk, the receiver should silently discard the packet
706 * and take no further action.
708 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
712 * This will discard packets with INIT chunk bundled as
713 * subsequent chunks in the packet. When INIT is first,
714 * the normal INIT processing will discard the chunk.
716 if (SCTP_CID_INIT
== ch
->type
&& (void *)ch
!= skb
->data
)
719 ch
= (sctp_chunkhdr_t
*) ch_end
;
720 } while (ch_end
< skb_tail_pointer(skb
));
728 /* Insert endpoint into the hash table. */
729 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
731 struct net
*net
= sock_net(ep
->base
.sk
);
732 struct sctp_ep_common
*epb
;
733 struct sctp_hashbucket
*head
;
737 epb
->hashent
= sctp_ep_hashfn(net
, epb
->bind_addr
.port
);
738 head
= &sctp_ep_hashtable
[epb
->hashent
];
740 sctp_write_lock(&head
->lock
);
741 hlist_add_head(&epb
->node
, &head
->chain
);
742 sctp_write_unlock(&head
->lock
);
745 /* Add an endpoint to the hash. Local BH-safe. */
746 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
748 sctp_local_bh_disable();
749 __sctp_hash_endpoint(ep
);
750 sctp_local_bh_enable();
753 /* Remove endpoint from the hash table. */
754 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
756 struct net
*net
= sock_net(ep
->base
.sk
);
757 struct sctp_hashbucket
*head
;
758 struct sctp_ep_common
*epb
;
762 epb
->hashent
= sctp_ep_hashfn(net
, epb
->bind_addr
.port
);
764 head
= &sctp_ep_hashtable
[epb
->hashent
];
766 sctp_write_lock(&head
->lock
);
767 hlist_del_init(&epb
->node
);
768 sctp_write_unlock(&head
->lock
);
771 /* Remove endpoint from the hash. Local BH-safe. */
772 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
774 sctp_local_bh_disable();
775 __sctp_unhash_endpoint(ep
);
776 sctp_local_bh_enable();
779 /* Look up an endpoint. */
780 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(struct net
*net
,
781 const union sctp_addr
*laddr
)
783 struct sctp_hashbucket
*head
;
784 struct sctp_ep_common
*epb
;
785 struct sctp_endpoint
*ep
;
786 struct hlist_node
*node
;
789 hash
= sctp_ep_hashfn(net
, ntohs(laddr
->v4
.sin_port
));
790 head
= &sctp_ep_hashtable
[hash
];
791 read_lock(&head
->lock
);
792 sctp_for_each_hentry(epb
, node
, &head
->chain
) {
794 if (sctp_endpoint_is_match(ep
, net
, laddr
))
798 ep
= sctp_sk(net
->sctp
.ctl_sock
)->ep
;
801 sctp_endpoint_hold(ep
);
802 read_unlock(&head
->lock
);
806 /* Insert association into the hash table. */
807 static void __sctp_hash_established(struct sctp_association
*asoc
)
809 struct net
*net
= sock_net(asoc
->base
.sk
);
810 struct sctp_ep_common
*epb
;
811 struct sctp_hashbucket
*head
;
815 /* Calculate which chain this entry will belong to. */
816 epb
->hashent
= sctp_assoc_hashfn(net
, epb
->bind_addr
.port
,
819 head
= &sctp_assoc_hashtable
[epb
->hashent
];
821 sctp_write_lock(&head
->lock
);
822 hlist_add_head(&epb
->node
, &head
->chain
);
823 sctp_write_unlock(&head
->lock
);
826 /* Add an association to the hash. Local BH-safe. */
827 void sctp_hash_established(struct sctp_association
*asoc
)
832 sctp_local_bh_disable();
833 __sctp_hash_established(asoc
);
834 sctp_local_bh_enable();
837 /* Remove association from the hash table. */
838 static void __sctp_unhash_established(struct sctp_association
*asoc
)
840 struct net
*net
= sock_net(asoc
->base
.sk
);
841 struct sctp_hashbucket
*head
;
842 struct sctp_ep_common
*epb
;
846 epb
->hashent
= sctp_assoc_hashfn(net
, epb
->bind_addr
.port
,
849 head
= &sctp_assoc_hashtable
[epb
->hashent
];
851 sctp_write_lock(&head
->lock
);
852 hlist_del_init(&epb
->node
);
853 sctp_write_unlock(&head
->lock
);
856 /* Remove association from the hash table. Local BH-safe. */
857 void sctp_unhash_established(struct sctp_association
*asoc
)
862 sctp_local_bh_disable();
863 __sctp_unhash_established(asoc
);
864 sctp_local_bh_enable();
867 /* Look up an association. */
868 static struct sctp_association
*__sctp_lookup_association(
870 const union sctp_addr
*local
,
871 const union sctp_addr
*peer
,
872 struct sctp_transport
**pt
)
874 struct sctp_hashbucket
*head
;
875 struct sctp_ep_common
*epb
;
876 struct sctp_association
*asoc
;
877 struct sctp_transport
*transport
;
878 struct hlist_node
*node
;
881 /* Optimize here for direct hit, only listening connections can
882 * have wildcards anyways.
884 hash
= sctp_assoc_hashfn(net
, ntohs(local
->v4
.sin_port
),
885 ntohs(peer
->v4
.sin_port
));
886 head
= &sctp_assoc_hashtable
[hash
];
887 read_lock(&head
->lock
);
888 sctp_for_each_hentry(epb
, node
, &head
->chain
) {
889 asoc
= sctp_assoc(epb
);
890 transport
= sctp_assoc_is_match(asoc
, net
, local
, peer
);
895 read_unlock(&head
->lock
);
901 sctp_association_hold(asoc
);
902 read_unlock(&head
->lock
);
906 /* Look up an association. BH-safe. */
908 struct sctp_association
*sctp_lookup_association(struct net
*net
,
909 const union sctp_addr
*laddr
,
910 const union sctp_addr
*paddr
,
911 struct sctp_transport
**transportp
)
913 struct sctp_association
*asoc
;
915 sctp_local_bh_disable();
916 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, transportp
);
917 sctp_local_bh_enable();
922 /* Is there an association matching the given local and peer addresses? */
923 int sctp_has_association(struct net
*net
,
924 const union sctp_addr
*laddr
,
925 const union sctp_addr
*paddr
)
927 struct sctp_association
*asoc
;
928 struct sctp_transport
*transport
;
930 if ((asoc
= sctp_lookup_association(net
, laddr
, paddr
, &transport
))) {
931 sctp_association_put(asoc
);
939 * SCTP Implementors Guide, 2.18 Handling of address
940 * parameters within the INIT or INIT-ACK.
942 * D) When searching for a matching TCB upon reception of an INIT
943 * or INIT-ACK chunk the receiver SHOULD use not only the
944 * source address of the packet (containing the INIT or
945 * INIT-ACK) but the receiver SHOULD also use all valid
946 * address parameters contained within the chunk.
948 * 2.18.3 Solution description
950 * This new text clearly specifies to an implementor the need
951 * to look within the INIT or INIT-ACK. Any implementation that
952 * does not do this, may not be able to establish associations
953 * in certain circumstances.
956 static struct sctp_association
*__sctp_rcv_init_lookup(struct net
*net
,
958 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
960 struct sctp_association
*asoc
;
961 union sctp_addr addr
;
962 union sctp_addr
*paddr
= &addr
;
963 struct sctphdr
*sh
= sctp_hdr(skb
);
964 union sctp_params params
;
965 sctp_init_chunk_t
*init
;
966 struct sctp_transport
*transport
;
970 * This code will NOT touch anything inside the chunk--it is
971 * strictly READ-ONLY.
973 * RFC 2960 3 SCTP packet Format
975 * Multiple chunks can be bundled into one SCTP packet up to
976 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
977 * COMPLETE chunks. These chunks MUST NOT be bundled with any
978 * other chunk in a packet. See Section 6.10 for more details
982 /* Find the start of the TLVs and the end of the chunk. This is
983 * the region we search for address parameters.
985 init
= (sctp_init_chunk_t
*)skb
->data
;
987 /* Walk the parameters looking for embedded addresses. */
988 sctp_walk_params(params
, init
, init_hdr
.params
) {
990 /* Note: Ignoring hostname addresses. */
991 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
995 af
->from_addr_param(paddr
, params
.addr
, sh
->source
, 0);
997 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, &transport
);
1005 /* ADD-IP, Section 5.2
1006 * When an endpoint receives an ASCONF Chunk from the remote peer
1007 * special procedures may be needed to identify the association the
1008 * ASCONF Chunk is associated with. To properly find the association
1009 * the following procedures SHOULD be followed:
1011 * D2) If the association is not found, use the address found in the
1012 * Address Parameter TLV combined with the port number found in the
1013 * SCTP common header. If found proceed to rule D4.
1015 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1016 * address found in the ASCONF Address Parameter TLV of each of the
1017 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1019 static struct sctp_association
*__sctp_rcv_asconf_lookup(
1021 sctp_chunkhdr_t
*ch
,
1022 const union sctp_addr
*laddr
,
1024 struct sctp_transport
**transportp
)
1026 sctp_addip_chunk_t
*asconf
= (struct sctp_addip_chunk
*)ch
;
1028 union sctp_addr_param
*param
;
1029 union sctp_addr paddr
;
1031 /* Skip over the ADDIP header and find the Address parameter */
1032 param
= (union sctp_addr_param
*)(asconf
+ 1);
1034 af
= sctp_get_af_specific(param_type2af(param
->p
.type
));
1038 af
->from_addr_param(&paddr
, param
, peer_port
, 0);
1040 return __sctp_lookup_association(net
, laddr
, &paddr
, transportp
);
1044 /* SCTP-AUTH, Section 6.3:
1045 * If the receiver does not find a STCB for a packet containing an AUTH
1046 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1047 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1050 * This means that any chunks that can help us identify the association need
1051 * to be looked at to find this association.
1053 static struct sctp_association
*__sctp_rcv_walk_lookup(struct net
*net
,
1054 struct sk_buff
*skb
,
1055 const union sctp_addr
*laddr
,
1056 struct sctp_transport
**transportp
)
1058 struct sctp_association
*asoc
= NULL
;
1059 sctp_chunkhdr_t
*ch
;
1061 unsigned int chunk_num
= 1;
1064 /* Walk through the chunks looking for AUTH or ASCONF chunks
1065 * to help us find the association.
1067 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1069 /* Break out if chunk length is less then minimal. */
1070 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
1073 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
1074 if (ch_end
> skb_tail_pointer(skb
))
1079 have_auth
= chunk_num
;
1082 case SCTP_CID_COOKIE_ECHO
:
1083 /* If a packet arrives containing an AUTH chunk as
1084 * a first chunk, a COOKIE-ECHO chunk as the second
1085 * chunk, and possibly more chunks after them, and
1086 * the receiver does not have an STCB for that
1087 * packet, then authentication is based on
1088 * the contents of the COOKIE- ECHO chunk.
1090 if (have_auth
== 1 && chunk_num
== 2)
1094 case SCTP_CID_ASCONF
:
1095 if (have_auth
|| sctp_addip_noauth
)
1096 asoc
= __sctp_rcv_asconf_lookup(
1098 sctp_hdr(skb
)->source
,
1107 ch
= (sctp_chunkhdr_t
*) ch_end
;
1109 } while (ch_end
< skb_tail_pointer(skb
));
1115 * There are circumstances when we need to look inside the SCTP packet
1116 * for information to help us find the association. Examples
1117 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1120 static struct sctp_association
*__sctp_rcv_lookup_harder(struct net
*net
,
1121 struct sk_buff
*skb
,
1122 const union sctp_addr
*laddr
,
1123 struct sctp_transport
**transportp
)
1125 sctp_chunkhdr_t
*ch
;
1127 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1129 /* The code below will attempt to walk the chunk and extract
1130 * parameter information. Before we do that, we need to verify
1131 * that the chunk length doesn't cause overflow. Otherwise, we'll
1134 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
1137 /* If this is INIT/INIT-ACK look inside the chunk too. */
1140 case SCTP_CID_INIT_ACK
:
1141 return __sctp_rcv_init_lookup(net
, skb
, laddr
, transportp
);
1145 return __sctp_rcv_walk_lookup(net
, skb
, laddr
, transportp
);
1153 /* Lookup an association for an inbound skb. */
1154 static struct sctp_association
*__sctp_rcv_lookup(struct net
*net
,
1155 struct sk_buff
*skb
,
1156 const union sctp_addr
*paddr
,
1157 const union sctp_addr
*laddr
,
1158 struct sctp_transport
**transportp
)
1160 struct sctp_association
*asoc
;
1162 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, transportp
);
1164 /* Further lookup for INIT/INIT-ACK packets.
1165 * SCTP Implementors Guide, 2.18 Handling of address
1166 * parameters within the INIT or INIT-ACK.
1169 asoc
= __sctp_rcv_lookup_harder(net
, skb
, laddr
, transportp
);