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 void 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 sk_buff
*list
= skb_shinfo(skb
)->frag_list
;
85 struct sctphdr
*sh
= sctp_hdr(skb
);
86 __be32 cmp
= sh
->checksum
;
87 __be32 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 struct sctp_input_cb
{
105 struct inet_skb_parm h4
;
106 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
107 struct inet6_skb_parm h6
;
110 struct sctp_chunk
*chunk
;
112 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
115 * This is the routine which IP calls when receiving an SCTP packet.
117 int sctp_rcv(struct sk_buff
*skb
)
120 struct sctp_association
*asoc
;
121 struct sctp_endpoint
*ep
= NULL
;
122 struct sctp_ep_common
*rcvr
;
123 struct sctp_transport
*transport
= NULL
;
124 struct sctp_chunk
*chunk
;
127 union sctp_addr dest
;
131 if (skb
->pkt_type
!=PACKET_HOST
)
134 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS
);
136 if (skb_linearize(skb
))
141 /* Pull up the IP and SCTP headers. */
142 __skb_pull(skb
, skb_transport_offset(skb
));
143 if (skb
->len
< sizeof(struct sctphdr
))
145 if (!sctp_checksum_disable
&& !skb_csum_unnecessary(skb
) &&
146 sctp_rcv_checksum(skb
) < 0)
149 skb_pull(skb
, sizeof(struct sctphdr
));
151 /* Make sure we at least have chunk headers worth of data left. */
152 if (skb
->len
< sizeof(struct sctp_chunkhdr
))
155 family
= ipver2af(ip_hdr(skb
)->version
);
156 af
= sctp_get_af_specific(family
);
160 /* Initialize local addresses for lookups. */
161 af
->from_skb(&src
, skb
, 1);
162 af
->from_skb(&dest
, skb
, 0);
164 /* If the packet is to or from a non-unicast address,
165 * silently discard the packet.
167 * This is not clearly defined in the RFC except in section
168 * 8.4 - OOTB handling. However, based on the book "Stream Control
169 * Transmission Protocol" 2.1, "It is important to note that the
170 * IP address of an SCTP transport address must be a routable
171 * unicast address. In other words, IP multicast addresses and
172 * IP broadcast addresses cannot be used in an SCTP transport
175 if (!af
->addr_valid(&src
, NULL
, skb
) ||
176 !af
->addr_valid(&dest
, NULL
, skb
))
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
)))
195 sctp_association_put(asoc
);
198 sctp_endpoint_put(ep
);
201 sk
= sctp_get_ctl_sock();
202 ep
= sctp_sk(sk
)->ep
;
203 sctp_endpoint_hold(ep
);
208 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
209 * An SCTP packet is called an "out of the blue" (OOTB)
210 * packet if it is correctly formed, i.e., passed the
211 * receiver's checksum check, but the receiver is not
212 * able to identify the association to which this
216 if (sctp_rcv_ootb(skb
)) {
217 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES
);
218 goto discard_release
;
222 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
223 goto discard_release
;
226 if (sk_filter(sk
, skb
))
227 goto discard_release
;
229 /* Create an SCTP packet structure. */
230 chunk
= sctp_chunkify(skb
, asoc
, sk
);
232 goto discard_release
;
233 SCTP_INPUT_CB(skb
)->chunk
= chunk
;
235 /* Remember what endpoint is to handle this packet. */
238 /* Remember the SCTP header. */
239 chunk
->sctp_hdr
= sh
;
241 /* Set the source and destination addresses of the incoming chunk. */
242 sctp_init_addrs(chunk
, &src
, &dest
);
244 /* Remember where we came from. */
245 chunk
->transport
= transport
;
247 /* Acquire access to the sock lock. Note: We are safe from other
248 * bottom halves on this lock, but a user may be in the lock too,
249 * so check if it is busy.
251 sctp_bh_lock_sock(sk
);
253 if (sk
!= rcvr
->sk
) {
254 /* Our cached sk is different from the rcvr->sk. This is
255 * because migrate()/accept() may have moved the association
256 * to a new socket and released all the sockets. So now we
257 * are holding a lock on the old socket while the user may
258 * be doing something with the new socket. Switch our veiw
261 sctp_bh_unlock_sock(sk
);
263 sctp_bh_lock_sock(sk
);
266 if (sock_owned_by_user(sk
)) {
267 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG
);
268 sctp_add_backlog(sk
, skb
);
270 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ
);
271 sctp_inq_push(&chunk
->rcvr
->inqueue
, chunk
);
274 sctp_bh_unlock_sock(sk
);
276 /* Release the asoc/ep ref we took in the lookup calls. */
278 sctp_association_put(asoc
);
280 sctp_endpoint_put(ep
);
285 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS
);
290 /* Release the asoc/ep ref we took in the lookup calls. */
292 sctp_association_put(asoc
);
294 sctp_endpoint_put(ep
);
299 /* Process the backlog queue of the socket. Every skb on
300 * the backlog holds a ref on an association or endpoint.
301 * We hold this ref throughout the state machine to make
302 * sure that the structure we need is still around.
304 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
306 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
307 struct sctp_inq
*inqueue
= &chunk
->rcvr
->inqueue
;
308 struct sctp_ep_common
*rcvr
= NULL
;
313 /* If the rcvr is dead then the association or endpoint
314 * has been deleted and we can safely drop the chunk
315 * and refs that we are holding.
318 sctp_chunk_free(chunk
);
322 if (unlikely(rcvr
->sk
!= sk
)) {
323 /* In this case, the association moved from one socket to
324 * another. We are currently sitting on the backlog of the
325 * old socket, so we need to move.
326 * However, since we are here in the process context we
327 * need to take make sure that the user doesn't own
328 * the new socket when we process the packet.
329 * If the new socket is user-owned, queue the chunk to the
330 * backlog of the new socket without dropping any refs.
331 * Otherwise, we can safely push the chunk on the inqueue.
335 sctp_bh_lock_sock(sk
);
337 if (sock_owned_by_user(sk
)) {
338 sk_add_backlog(sk
, skb
);
341 sctp_inq_push(inqueue
, chunk
);
343 sctp_bh_unlock_sock(sk
);
345 /* If the chunk was backloged again, don't drop refs */
349 sctp_inq_push(inqueue
, chunk
);
353 /* Release the refs we took in sctp_add_backlog */
354 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
355 sctp_association_put(sctp_assoc(rcvr
));
356 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
357 sctp_endpoint_put(sctp_ep(rcvr
));
364 static void sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
366 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
367 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
369 /* Hold the assoc/ep while hanging on the backlog queue.
370 * This way, we know structures we need will not disappear from us
372 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
373 sctp_association_hold(sctp_assoc(rcvr
));
374 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
375 sctp_endpoint_hold(sctp_ep(rcvr
));
379 sk_add_backlog(sk
, skb
);
382 /* Handle icmp frag needed error. */
383 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
384 struct sctp_transport
*t
, __u32 pmtu
)
386 if (!t
|| (t
->pathmtu
<= pmtu
))
389 if (sock_owned_by_user(sk
)) {
390 asoc
->pmtu_pending
= 1;
395 if (t
->param_flags
& SPP_PMTUD_ENABLE
) {
396 /* Update transports view of the MTU */
397 sctp_transport_update_pmtu(t
, pmtu
);
399 /* Update association pmtu. */
400 sctp_assoc_sync_pmtu(asoc
);
403 /* Retransmit with the new pmtu setting.
404 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
405 * Needed will never be sent, but if a message was sent before
406 * PMTU discovery was disabled that was larger than the PMTU, it
407 * would not be fragmented, so it must be re-transmitted fragmented.
409 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
413 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
415 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
416 * or a "Protocol Unreachable" treat this message as an abort
417 * with the T bit set.
419 * This function sends an event to the state machine, which will abort the
423 void sctp_icmp_proto_unreachable(struct sock
*sk
,
424 struct sctp_association
*asoc
,
425 struct sctp_transport
*t
)
427 SCTP_DEBUG_PRINTK("%s\n", __func__
);
429 sctp_do_sm(SCTP_EVENT_T_OTHER
,
430 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
431 asoc
->state
, asoc
->ep
, asoc
, t
,
436 /* Common lookup code for icmp/icmpv6 error handler. */
437 struct sock
*sctp_err_lookup(int family
, struct sk_buff
*skb
,
438 struct sctphdr
*sctphdr
,
439 struct sctp_association
**app
,
440 struct sctp_transport
**tpp
)
442 union sctp_addr saddr
;
443 union sctp_addr daddr
;
445 struct sock
*sk
= NULL
;
446 struct sctp_association
*asoc
;
447 struct sctp_transport
*transport
= NULL
;
448 struct sctp_init_chunk
*chunkhdr
;
449 __u32 vtag
= ntohl(sctphdr
->vtag
);
450 int len
= skb
->len
- ((void *)sctphdr
- (void *)skb
->data
);
452 *app
= NULL
; *tpp
= NULL
;
454 af
= sctp_get_af_specific(family
);
459 /* Initialize local addresses for lookups. */
460 af
->from_skb(&saddr
, skb
, 1);
461 af
->from_skb(&daddr
, skb
, 0);
463 /* Look for an association that matches the incoming ICMP error
466 asoc
= __sctp_lookup_association(&saddr
, &daddr
, &transport
);
472 /* RFC 4960, Appendix C. ICMP Handling
474 * ICMP6) An implementation MUST validate that the Verification Tag
475 * contained in the ICMP message matches the Verification Tag of
476 * the peer. If the Verification Tag is not 0 and does NOT
477 * match, discard the ICMP message. If it is 0 and the ICMP
478 * message contains enough bytes to verify that the chunk type is
479 * an INIT chunk and that the Initiate Tag matches the tag of the
480 * peer, continue with ICMP7. If the ICMP message is too short
481 * or the chunk type or the Initiate Tag does not match, silently
482 * discard the packet.
485 chunkhdr
= (struct sctp_init_chunk
*)((void *)sctphdr
486 + sizeof(struct sctphdr
));
487 if (len
< sizeof(struct sctphdr
) + sizeof(sctp_chunkhdr_t
)
489 chunkhdr
->chunk_hdr
.type
!= SCTP_CID_INIT
||
490 ntohl(chunkhdr
->init_hdr
.init_tag
) != asoc
->c
.my_vtag
) {
493 } else if (vtag
!= asoc
->c
.peer_vtag
) {
497 sctp_bh_lock_sock(sk
);
499 /* If too many ICMPs get dropped on busy
500 * servers this needs to be solved differently.
502 if (sock_owned_by_user(sk
))
503 NET_INC_STATS_BH(&init_net
, LINUX_MIB_LOCKDROPPEDICMPS
);
511 sctp_association_put(asoc
);
515 /* Common cleanup code for icmp/icmpv6 error handler. */
516 void sctp_err_finish(struct sock
*sk
, struct sctp_association
*asoc
)
518 sctp_bh_unlock_sock(sk
);
520 sctp_association_put(asoc
);
524 * This routine is called by the ICMP module when it gets some
525 * sort of error condition. If err < 0 then the socket should
526 * be closed and the error returned to the user. If err > 0
527 * it's just the icmp type << 8 | icmp code. After adjustment
528 * header points to the first 8 bytes of the sctp header. We need
529 * to find the appropriate port.
531 * The locking strategy used here is very "optimistic". When
532 * someone else accesses the socket the ICMP is just dropped
533 * and for some paths there is no check at all.
534 * A more general error queue to queue errors for later handling
535 * is probably better.
538 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
540 struct iphdr
*iph
= (struct iphdr
*)skb
->data
;
541 const int ihlen
= iph
->ihl
* 4;
542 const int type
= icmp_hdr(skb
)->type
;
543 const int code
= icmp_hdr(skb
)->code
;
545 struct sctp_association
*asoc
= NULL
;
546 struct sctp_transport
*transport
;
547 struct inet_sock
*inet
;
548 sk_buff_data_t saveip
, savesctp
;
551 if (skb
->len
< ihlen
+ 8) {
552 ICMP_INC_STATS_BH(&init_net
, ICMP_MIB_INERRORS
);
556 /* Fix up skb to look at the embedded net header. */
557 saveip
= skb
->network_header
;
558 savesctp
= skb
->transport_header
;
559 skb_reset_network_header(skb
);
560 skb_set_transport_header(skb
, ihlen
);
561 sk
= sctp_err_lookup(AF_INET
, skb
, sctp_hdr(skb
), &asoc
, &transport
);
562 /* Put back, the original values. */
563 skb
->network_header
= saveip
;
564 skb
->transport_header
= savesctp
;
566 ICMP_INC_STATS_BH(&init_net
, ICMP_MIB_INERRORS
);
569 /* Warning: The sock lock is held. Remember to call
574 case ICMP_PARAMETERPROB
:
577 case ICMP_DEST_UNREACH
:
578 if (code
> NR_ICMP_UNREACH
)
581 /* PMTU discovery (RFC1191) */
582 if (ICMP_FRAG_NEEDED
== code
) {
583 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
587 if (ICMP_PROT_UNREACH
== code
) {
588 sctp_icmp_proto_unreachable(sk
, asoc
,
593 err
= icmp_err_convert
[code
].errno
;
595 case ICMP_TIME_EXCEEDED
:
596 /* Ignore any time exceeded errors due to fragment reassembly
599 if (ICMP_EXC_FRAGTIME
== code
)
609 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
611 sk
->sk_error_report(sk
);
612 } else { /* Only an error on timeout */
613 sk
->sk_err_soft
= err
;
617 sctp_err_finish(sk
, asoc
);
621 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
623 * This function scans all the chunks in the OOTB packet to determine if
624 * the packet should be discarded right away. If a response might be needed
625 * for this packet, or, if further processing is possible, the packet will
626 * be queued to a proper inqueue for the next phase of handling.
629 * Return 0 - If further processing is needed.
630 * Return 1 - If the packet can be discarded right away.
632 static int sctp_rcv_ootb(struct sk_buff
*skb
)
638 ch
= (sctp_chunkhdr_t
*) skb
->data
;
640 /* Scan through all the chunks in the packet. */
642 /* Break out if chunk length is less then minimal. */
643 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
646 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
647 if (ch_end
> skb_tail_pointer(skb
))
650 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
651 * receiver MUST silently discard the OOTB packet and take no
654 if (SCTP_CID_ABORT
== ch
->type
)
657 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
658 * chunk, the receiver should silently discard the packet
659 * and take no further action.
661 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
665 * This will discard packets with INIT chunk bundled as
666 * subsequent chunks in the packet. When INIT is first,
667 * the normal INIT processing will discard the chunk.
669 if (SCTP_CID_INIT
== ch
->type
&& (void *)ch
!= skb
->data
)
672 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
673 * or a COOKIE ACK the SCTP Packet should be silently
676 if (SCTP_CID_COOKIE_ACK
== ch
->type
)
679 if (SCTP_CID_ERROR
== ch
->type
) {
680 sctp_walk_errors(err
, ch
) {
681 if (SCTP_ERROR_STALE_COOKIE
== err
->cause
)
686 ch
= (sctp_chunkhdr_t
*) ch_end
;
687 } while (ch_end
< skb_tail_pointer(skb
));
695 /* Insert endpoint into the hash table. */
696 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
698 struct sctp_ep_common
*epb
;
699 struct sctp_hashbucket
*head
;
703 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
704 head
= &sctp_ep_hashtable
[epb
->hashent
];
706 sctp_write_lock(&head
->lock
);
707 hlist_add_head(&epb
->node
, &head
->chain
);
708 sctp_write_unlock(&head
->lock
);
711 /* Add an endpoint to the hash. Local BH-safe. */
712 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
714 sctp_local_bh_disable();
715 __sctp_hash_endpoint(ep
);
716 sctp_local_bh_enable();
719 /* Remove endpoint from the hash table. */
720 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
722 struct sctp_hashbucket
*head
;
723 struct sctp_ep_common
*epb
;
727 if (hlist_unhashed(&epb
->node
))
730 epb
->hashent
= sctp_ep_hashfn(epb
->bind_addr
.port
);
732 head
= &sctp_ep_hashtable
[epb
->hashent
];
734 sctp_write_lock(&head
->lock
);
735 __hlist_del(&epb
->node
);
736 sctp_write_unlock(&head
->lock
);
739 /* Remove endpoint from the hash. Local BH-safe. */
740 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
742 sctp_local_bh_disable();
743 __sctp_unhash_endpoint(ep
);
744 sctp_local_bh_enable();
747 /* Look up an endpoint. */
748 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(const union sctp_addr
*laddr
)
750 struct sctp_hashbucket
*head
;
751 struct sctp_ep_common
*epb
;
752 struct sctp_endpoint
*ep
;
753 struct hlist_node
*node
;
756 hash
= sctp_ep_hashfn(ntohs(laddr
->v4
.sin_port
));
757 head
= &sctp_ep_hashtable
[hash
];
758 read_lock(&head
->lock
);
759 sctp_for_each_hentry(epb
, node
, &head
->chain
) {
761 if (sctp_endpoint_is_match(ep
, laddr
))
765 ep
= sctp_sk((sctp_get_ctl_sock()))->ep
;
768 sctp_endpoint_hold(ep
);
769 read_unlock(&head
->lock
);
773 /* Insert association into the hash table. */
774 static void __sctp_hash_established(struct sctp_association
*asoc
)
776 struct sctp_ep_common
*epb
;
777 struct sctp_hashbucket
*head
;
781 /* Calculate which chain this entry will belong to. */
782 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
, asoc
->peer
.port
);
784 head
= &sctp_assoc_hashtable
[epb
->hashent
];
786 sctp_write_lock(&head
->lock
);
787 hlist_add_head(&epb
->node
, &head
->chain
);
788 sctp_write_unlock(&head
->lock
);
791 /* Add an association to the hash. Local BH-safe. */
792 void sctp_hash_established(struct sctp_association
*asoc
)
797 sctp_local_bh_disable();
798 __sctp_hash_established(asoc
);
799 sctp_local_bh_enable();
802 /* Remove association from the hash table. */
803 static void __sctp_unhash_established(struct sctp_association
*asoc
)
805 struct sctp_hashbucket
*head
;
806 struct sctp_ep_common
*epb
;
810 epb
->hashent
= sctp_assoc_hashfn(epb
->bind_addr
.port
,
813 head
= &sctp_assoc_hashtable
[epb
->hashent
];
815 sctp_write_lock(&head
->lock
);
816 __hlist_del(&epb
->node
);
817 sctp_write_unlock(&head
->lock
);
820 /* Remove association from the hash table. Local BH-safe. */
821 void sctp_unhash_established(struct sctp_association
*asoc
)
826 sctp_local_bh_disable();
827 __sctp_unhash_established(asoc
);
828 sctp_local_bh_enable();
831 /* Look up an association. */
832 static struct sctp_association
*__sctp_lookup_association(
833 const union sctp_addr
*local
,
834 const union sctp_addr
*peer
,
835 struct sctp_transport
**pt
)
837 struct sctp_hashbucket
*head
;
838 struct sctp_ep_common
*epb
;
839 struct sctp_association
*asoc
;
840 struct sctp_transport
*transport
;
841 struct hlist_node
*node
;
844 /* Optimize here for direct hit, only listening connections can
845 * have wildcards anyways.
847 hash
= sctp_assoc_hashfn(ntohs(local
->v4
.sin_port
), ntohs(peer
->v4
.sin_port
));
848 head
= &sctp_assoc_hashtable
[hash
];
849 read_lock(&head
->lock
);
850 sctp_for_each_hentry(epb
, node
, &head
->chain
) {
851 asoc
= sctp_assoc(epb
);
852 transport
= sctp_assoc_is_match(asoc
, local
, peer
);
857 read_unlock(&head
->lock
);
863 sctp_association_hold(asoc
);
864 read_unlock(&head
->lock
);
868 /* Look up an association. BH-safe. */
870 struct sctp_association
*sctp_lookup_association(const union sctp_addr
*laddr
,
871 const union sctp_addr
*paddr
,
872 struct sctp_transport
**transportp
)
874 struct sctp_association
*asoc
;
876 sctp_local_bh_disable();
877 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
878 sctp_local_bh_enable();
883 /* Is there an association matching the given local and peer addresses? */
884 int sctp_has_association(const union sctp_addr
*laddr
,
885 const union sctp_addr
*paddr
)
887 struct sctp_association
*asoc
;
888 struct sctp_transport
*transport
;
890 if ((asoc
= sctp_lookup_association(laddr
, paddr
, &transport
))) {
891 sctp_association_put(asoc
);
899 * SCTP Implementors Guide, 2.18 Handling of address
900 * parameters within the INIT or INIT-ACK.
902 * D) When searching for a matching TCB upon reception of an INIT
903 * or INIT-ACK chunk the receiver SHOULD use not only the
904 * source address of the packet (containing the INIT or
905 * INIT-ACK) but the receiver SHOULD also use all valid
906 * address parameters contained within the chunk.
908 * 2.18.3 Solution description
910 * This new text clearly specifies to an implementor the need
911 * to look within the INIT or INIT-ACK. Any implementation that
912 * does not do this, may not be able to establish associations
913 * in certain circumstances.
916 static struct sctp_association
*__sctp_rcv_init_lookup(struct sk_buff
*skb
,
917 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
919 struct sctp_association
*asoc
;
920 union sctp_addr addr
;
921 union sctp_addr
*paddr
= &addr
;
922 struct sctphdr
*sh
= sctp_hdr(skb
);
924 union sctp_params params
;
925 sctp_init_chunk_t
*init
;
926 struct sctp_transport
*transport
;
929 ch
= (sctp_chunkhdr_t
*) skb
->data
;
932 * This code will NOT touch anything inside the chunk--it is
933 * strictly READ-ONLY.
935 * RFC 2960 3 SCTP packet Format
937 * Multiple chunks can be bundled into one SCTP packet up to
938 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
939 * COMPLETE chunks. These chunks MUST NOT be bundled with any
940 * other chunk in a packet. See Section 6.10 for more details
944 /* Find the start of the TLVs and the end of the chunk. This is
945 * the region we search for address parameters.
947 init
= (sctp_init_chunk_t
*)skb
->data
;
949 /* Walk the parameters looking for embedded addresses. */
950 sctp_walk_params(params
, init
, init_hdr
.params
) {
952 /* Note: Ignoring hostname addresses. */
953 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
957 af
->from_addr_param(paddr
, params
.addr
, sh
->source
, 0);
959 asoc
= __sctp_lookup_association(laddr
, paddr
, &transport
);
967 /* ADD-IP, Section 5.2
968 * When an endpoint receives an ASCONF Chunk from the remote peer
969 * special procedures may be needed to identify the association the
970 * ASCONF Chunk is associated with. To properly find the association
971 * the following procedures SHOULD be followed:
973 * D2) If the association is not found, use the address found in the
974 * Address Parameter TLV combined with the port number found in the
975 * SCTP common header. If found proceed to rule D4.
977 * D2-ext) If more than one ASCONF Chunks are packed together, use the
978 * address found in the ASCONF Address Parameter TLV of each of the
979 * subsequent ASCONF Chunks. If found, proceed to rule D4.
981 static struct sctp_association
*__sctp_rcv_asconf_lookup(
983 const union sctp_addr
*laddr
,
985 struct sctp_transport
**transportp
)
987 sctp_addip_chunk_t
*asconf
= (struct sctp_addip_chunk
*)ch
;
989 union sctp_addr_param
*param
;
990 union sctp_addr paddr
;
992 /* Skip over the ADDIP header and find the Address parameter */
993 param
= (union sctp_addr_param
*)(asconf
+ 1);
995 af
= sctp_get_af_specific(param_type2af(param
->v4
.param_hdr
.type
));
999 af
->from_addr_param(&paddr
, param
, peer_port
, 0);
1001 return __sctp_lookup_association(laddr
, &paddr
, transportp
);
1005 /* SCTP-AUTH, Section 6.3:
1006 * If the receiver does not find a STCB for a packet containing an AUTH
1007 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1008 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1011 * This means that any chunks that can help us identify the association need
1012 * to be looked at to find this assocation.
1014 static struct sctp_association
*__sctp_rcv_walk_lookup(struct sk_buff
*skb
,
1015 const union sctp_addr
*laddr
,
1016 struct sctp_transport
**transportp
)
1018 struct sctp_association
*asoc
= NULL
;
1019 sctp_chunkhdr_t
*ch
;
1021 unsigned int chunk_num
= 1;
1024 /* Walk through the chunks looking for AUTH or ASCONF chunks
1025 * to help us find the association.
1027 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1029 /* Break out if chunk length is less then minimal. */
1030 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
1033 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
1034 if (ch_end
> skb_tail_pointer(skb
))
1039 have_auth
= chunk_num
;
1042 case SCTP_CID_COOKIE_ECHO
:
1043 /* If a packet arrives containing an AUTH chunk as
1044 * a first chunk, a COOKIE-ECHO chunk as the second
1045 * chunk, and possibly more chunks after them, and
1046 * the receiver does not have an STCB for that
1047 * packet, then authentication is based on
1048 * the contents of the COOKIE- ECHO chunk.
1050 if (have_auth
== 1 && chunk_num
== 2)
1054 case SCTP_CID_ASCONF
:
1055 if (have_auth
|| sctp_addip_noauth
)
1056 asoc
= __sctp_rcv_asconf_lookup(ch
, laddr
,
1057 sctp_hdr(skb
)->source
,
1066 ch
= (sctp_chunkhdr_t
*) ch_end
;
1068 } while (ch_end
< skb_tail_pointer(skb
));
1074 * There are circumstances when we need to look inside the SCTP packet
1075 * for information to help us find the association. Examples
1076 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1079 static struct sctp_association
*__sctp_rcv_lookup_harder(struct sk_buff
*skb
,
1080 const union sctp_addr
*laddr
,
1081 struct sctp_transport
**transportp
)
1083 sctp_chunkhdr_t
*ch
;
1085 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1087 /* The code below will attempt to walk the chunk and extract
1088 * parameter information. Before we do that, we need to verify
1089 * that the chunk length doesn't cause overflow. Otherwise, we'll
1092 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
1095 /* If this is INIT/INIT-ACK look inside the chunk too. */
1098 case SCTP_CID_INIT_ACK
:
1099 return __sctp_rcv_init_lookup(skb
, laddr
, transportp
);
1103 return __sctp_rcv_walk_lookup(skb
, laddr
, transportp
);
1111 /* Lookup an association for an inbound skb. */
1112 static struct sctp_association
*__sctp_rcv_lookup(struct sk_buff
*skb
,
1113 const union sctp_addr
*paddr
,
1114 const union sctp_addr
*laddr
,
1115 struct sctp_transport
**transportp
)
1117 struct sctp_association
*asoc
;
1119 asoc
= __sctp_lookup_association(laddr
, paddr
, transportp
);
1121 /* Further lookup for INIT/INIT-ACK packets.
1122 * SCTP Implementors Guide, 2.18 Handling of address
1123 * parameters within the INIT or INIT-ACK.
1126 asoc
= __sctp_rcv_lookup_harder(skb
, laddr
, transportp
);