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, see
27 * <http://www.gnu.org/licenses/>.
29 * Please send any bug reports or fixes you make to the
31 * lksctp developers <linux-sctp@vger.kernel.org>
33 * Written or modified by:
34 * La Monte H.P. Yarroll <piggy@acm.org>
35 * Karl Knutson <karl@athena.chicago.il.us>
36 * Xingang Guo <xingang.guo@intel.com>
37 * Jon Grimm <jgrimm@us.ibm.com>
38 * Hui Huang <hui.huang@nokia.com>
39 * Daisy Chang <daisyc@us.ibm.com>
40 * Sridhar Samudrala <sri@us.ibm.com>
41 * Ardelle Fan <ardelle.fan@intel.com>
44 #include <linux/types.h>
45 #include <linux/list.h> /* For struct list_head */
46 #include <linux/socket.h>
48 #include <linux/time.h> /* For struct timeval */
49 #include <linux/slab.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
57 #include <net/sctp/checksum.h>
58 #include <net/net_namespace.h>
60 /* Forward declarations for internal helpers. */
61 static int sctp_rcv_ootb(struct sk_buff
*);
62 static struct sctp_association
*__sctp_rcv_lookup(struct net
*net
,
64 const union sctp_addr
*paddr
,
65 const union sctp_addr
*laddr
,
66 struct sctp_transport
**transportp
);
67 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(struct net
*net
,
68 const union sctp_addr
*laddr
);
69 static struct sctp_association
*__sctp_lookup_association(
71 const union sctp_addr
*local
,
72 const union sctp_addr
*peer
,
73 struct sctp_transport
**pt
);
75 static int sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
);
78 /* Calculate the SCTP checksum of an SCTP packet. */
79 static inline int sctp_rcv_checksum(struct net
*net
, struct sk_buff
*skb
)
81 struct sctphdr
*sh
= sctp_hdr(skb
);
82 __le32 cmp
= sh
->checksum
;
83 __le32 val
= sctp_compute_cksum(skb
, 0);
86 /* CRC failure, dump it. */
87 SCTP_INC_STATS_BH(net
, SCTP_MIB_CHECKSUMERRORS
);
93 struct sctp_input_cb
{
95 struct inet_skb_parm h4
;
96 #if IS_ENABLED(CONFIG_IPV6)
97 struct inet6_skb_parm h6
;
100 struct sctp_chunk
*chunk
;
102 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
105 * This is the routine which IP calls when receiving an SCTP packet.
107 int sctp_rcv(struct sk_buff
*skb
)
110 struct sctp_association
*asoc
;
111 struct sctp_endpoint
*ep
= NULL
;
112 struct sctp_ep_common
*rcvr
;
113 struct sctp_transport
*transport
= NULL
;
114 struct sctp_chunk
*chunk
;
117 union sctp_addr dest
;
120 struct net
*net
= dev_net(skb
->dev
);
122 if (skb
->pkt_type
!= PACKET_HOST
)
125 SCTP_INC_STATS_BH(net
, SCTP_MIB_INSCTPPACKS
);
127 if (skb_linearize(skb
))
132 /* Pull up the IP and SCTP headers. */
133 __skb_pull(skb
, skb_transport_offset(skb
));
134 if (skb
->len
< sizeof(struct sctphdr
))
136 if (!sctp_checksum_disable
&& !skb_csum_unnecessary(skb
) &&
137 sctp_rcv_checksum(net
, skb
) < 0)
140 skb_pull(skb
, sizeof(struct sctphdr
));
142 /* Make sure we at least have chunk headers worth of data left. */
143 if (skb
->len
< sizeof(struct sctp_chunkhdr
))
146 family
= ipver2af(ip_hdr(skb
)->version
);
147 af
= sctp_get_af_specific(family
);
151 /* Initialize local addresses for lookups. */
152 af
->from_skb(&src
, skb
, 1);
153 af
->from_skb(&dest
, skb
, 0);
155 /* If the packet is to or from a non-unicast address,
156 * silently discard the packet.
158 * This is not clearly defined in the RFC except in section
159 * 8.4 - OOTB handling. However, based on the book "Stream Control
160 * Transmission Protocol" 2.1, "It is important to note that the
161 * IP address of an SCTP transport address must be a routable
162 * unicast address. In other words, IP multicast addresses and
163 * IP broadcast addresses cannot be used in an SCTP transport
166 if (!af
->addr_valid(&src
, NULL
, skb
) ||
167 !af
->addr_valid(&dest
, NULL
, skb
))
170 asoc
= __sctp_rcv_lookup(net
, skb
, &src
, &dest
, &transport
);
173 ep
= __sctp_rcv_lookup_endpoint(net
, &dest
);
175 /* Retrieve the common input handling substructure. */
176 rcvr
= asoc
? &asoc
->base
: &ep
->base
;
180 * If a frame arrives on an interface and the receiving socket is
181 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
183 if (sk
->sk_bound_dev_if
&& (sk
->sk_bound_dev_if
!= af
->skb_iif(skb
)))
186 sctp_association_put(asoc
);
189 sctp_endpoint_put(ep
);
192 sk
= net
->sctp
.ctl_sock
;
193 ep
= sctp_sk(sk
)->ep
;
194 sctp_endpoint_hold(ep
);
199 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
200 * An SCTP packet is called an "out of the blue" (OOTB)
201 * packet if it is correctly formed, i.e., passed the
202 * receiver's checksum check, but the receiver is not
203 * able to identify the association to which this
207 if (sctp_rcv_ootb(skb
)) {
208 SCTP_INC_STATS_BH(net
, SCTP_MIB_OUTOFBLUES
);
209 goto discard_release
;
213 if (!xfrm_policy_check(sk
, XFRM_POLICY_IN
, skb
, family
))
214 goto discard_release
;
217 if (sk_filter(sk
, skb
))
218 goto discard_release
;
220 /* Create an SCTP packet structure. */
221 chunk
= sctp_chunkify(skb
, asoc
, sk
);
223 goto discard_release
;
224 SCTP_INPUT_CB(skb
)->chunk
= chunk
;
226 /* Remember what endpoint is to handle this packet. */
229 /* Remember the SCTP header. */
230 chunk
->sctp_hdr
= sh
;
232 /* Set the source and destination addresses of the incoming chunk. */
233 sctp_init_addrs(chunk
, &src
, &dest
);
235 /* Remember where we came from. */
236 chunk
->transport
= transport
;
238 /* Acquire access to the sock lock. Note: We are safe from other
239 * bottom halves on this lock, but a user may be in the lock too,
240 * so check if it is busy.
242 sctp_bh_lock_sock(sk
);
244 if (sk
!= rcvr
->sk
) {
245 /* Our cached sk is different from the rcvr->sk. This is
246 * because migrate()/accept() may have moved the association
247 * to a new socket and released all the sockets. So now we
248 * are holding a lock on the old socket while the user may
249 * be doing something with the new socket. Switch our veiw
252 sctp_bh_unlock_sock(sk
);
254 sctp_bh_lock_sock(sk
);
257 if (sock_owned_by_user(sk
)) {
258 if (sctp_add_backlog(sk
, skb
)) {
259 sctp_bh_unlock_sock(sk
);
260 sctp_chunk_free(chunk
);
261 skb
= NULL
; /* sctp_chunk_free already freed the skb */
262 goto discard_release
;
264 SCTP_INC_STATS_BH(net
, SCTP_MIB_IN_PKT_BACKLOG
);
266 SCTP_INC_STATS_BH(net
, SCTP_MIB_IN_PKT_SOFTIRQ
);
267 sctp_inq_push(&chunk
->rcvr
->inqueue
, chunk
);
270 sctp_bh_unlock_sock(sk
);
272 /* Release the asoc/ep ref we took in the lookup calls. */
274 sctp_association_put(asoc
);
276 sctp_endpoint_put(ep
);
281 SCTP_INC_STATS_BH(net
, SCTP_MIB_IN_PKT_DISCARDS
);
286 /* Release the asoc/ep ref we took in the lookup calls. */
288 sctp_association_put(asoc
);
290 sctp_endpoint_put(ep
);
295 /* Process the backlog queue of the socket. Every skb on
296 * the backlog holds a ref on an association or endpoint.
297 * We hold this ref throughout the state machine to make
298 * sure that the structure we need is still around.
300 int sctp_backlog_rcv(struct sock
*sk
, struct sk_buff
*skb
)
302 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
303 struct sctp_inq
*inqueue
= &chunk
->rcvr
->inqueue
;
304 struct sctp_ep_common
*rcvr
= NULL
;
309 /* If the rcvr is dead then the association or endpoint
310 * has been deleted and we can safely drop the chunk
311 * and refs that we are holding.
314 sctp_chunk_free(chunk
);
318 if (unlikely(rcvr
->sk
!= sk
)) {
319 /* In this case, the association moved from one socket to
320 * another. We are currently sitting on the backlog of the
321 * old socket, so we need to move.
322 * However, since we are here in the process context we
323 * need to take make sure that the user doesn't own
324 * the new socket when we process the packet.
325 * If the new socket is user-owned, queue the chunk to the
326 * backlog of the new socket without dropping any refs.
327 * Otherwise, we can safely push the chunk on the inqueue.
331 sctp_bh_lock_sock(sk
);
333 if (sock_owned_by_user(sk
)) {
334 if (sk_add_backlog(sk
, skb
, sk
->sk_rcvbuf
))
335 sctp_chunk_free(chunk
);
339 sctp_inq_push(inqueue
, chunk
);
341 sctp_bh_unlock_sock(sk
);
343 /* If the chunk was backloged again, don't drop refs */
347 sctp_inq_push(inqueue
, chunk
);
351 /* Release the refs we took in sctp_add_backlog */
352 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
353 sctp_association_put(sctp_assoc(rcvr
));
354 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
355 sctp_endpoint_put(sctp_ep(rcvr
));
362 static int sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
364 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
365 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
368 ret
= sk_add_backlog(sk
, skb
, sk
->sk_rcvbuf
);
370 /* Hold the assoc/ep while hanging on the backlog queue.
371 * This way, we know structures we need will not disappear
374 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
375 sctp_association_hold(sctp_assoc(rcvr
));
376 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
377 sctp_endpoint_hold(sctp_ep(rcvr
));
385 /* Handle icmp frag needed error. */
386 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
387 struct sctp_transport
*t
, __u32 pmtu
)
389 if (!t
|| (t
->pathmtu
<= pmtu
))
392 if (sock_owned_by_user(sk
)) {
393 asoc
->pmtu_pending
= 1;
398 if (t
->param_flags
& SPP_PMTUD_ENABLE
) {
399 /* Update transports view of the MTU */
400 sctp_transport_update_pmtu(sk
, t
, pmtu
);
402 /* Update association pmtu. */
403 sctp_assoc_sync_pmtu(sk
, asoc
);
406 /* Retransmit with the new pmtu setting.
407 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
408 * Needed will never be sent, but if a message was sent before
409 * PMTU discovery was disabled that was larger than the PMTU, it
410 * would not be fragmented, so it must be re-transmitted fragmented.
412 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
415 void sctp_icmp_redirect(struct sock
*sk
, struct sctp_transport
*t
,
418 struct dst_entry
*dst
;
422 dst
= sctp_transport_dst_check(t
);
424 dst
->ops
->redirect(dst
, sk
, skb
);
428 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
430 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
431 * or a "Protocol Unreachable" treat this message as an abort
432 * with the T bit set.
434 * This function sends an event to the state machine, which will abort the
438 void sctp_icmp_proto_unreachable(struct sock
*sk
,
439 struct sctp_association
*asoc
,
440 struct sctp_transport
*t
)
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
);
451 struct net
*net
= sock_net(sk
);
453 pr_debug("%s: unrecognized next header type "
454 "encountered!\n", __func__
);
456 if (del_timer(&t
->proto_unreach_timer
))
457 sctp_association_put(asoc
);
459 sctp_do_sm(net
, SCTP_EVENT_T_OTHER
,
460 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
461 asoc
->state
, asoc
->ep
, asoc
, t
,
466 /* Common lookup code for icmp/icmpv6 error handler. */
467 struct sock
*sctp_err_lookup(struct net
*net
, int family
, struct sk_buff
*skb
,
468 struct sctphdr
*sctphdr
,
469 struct sctp_association
**app
,
470 struct sctp_transport
**tpp
)
472 union sctp_addr saddr
;
473 union sctp_addr daddr
;
475 struct sock
*sk
= NULL
;
476 struct sctp_association
*asoc
;
477 struct sctp_transport
*transport
= NULL
;
478 struct sctp_init_chunk
*chunkhdr
;
479 __u32 vtag
= ntohl(sctphdr
->vtag
);
480 int len
= skb
->len
- ((void *)sctphdr
- (void *)skb
->data
);
482 *app
= NULL
; *tpp
= NULL
;
484 af
= sctp_get_af_specific(family
);
489 /* Initialize local addresses for lookups. */
490 af
->from_skb(&saddr
, skb
, 1);
491 af
->from_skb(&daddr
, skb
, 0);
493 /* Look for an association that matches the incoming ICMP error
496 asoc
= __sctp_lookup_association(net
, &saddr
, &daddr
, &transport
);
502 /* RFC 4960, Appendix C. ICMP Handling
504 * ICMP6) An implementation MUST validate that the Verification Tag
505 * contained in the ICMP message matches the Verification Tag of
506 * the peer. If the Verification Tag is not 0 and does NOT
507 * match, discard the ICMP message. If it is 0 and the ICMP
508 * message contains enough bytes to verify that the chunk type is
509 * an INIT chunk and that the Initiate Tag matches the tag of the
510 * peer, continue with ICMP7. If the ICMP message is too short
511 * or the chunk type or the Initiate Tag does not match, silently
512 * discard the packet.
515 chunkhdr
= (void *)sctphdr
+ sizeof(struct sctphdr
);
516 if (len
< sizeof(struct sctphdr
) + sizeof(sctp_chunkhdr_t
)
518 chunkhdr
->chunk_hdr
.type
!= SCTP_CID_INIT
||
519 ntohl(chunkhdr
->init_hdr
.init_tag
) != asoc
->c
.my_vtag
) {
522 } else if (vtag
!= asoc
->c
.peer_vtag
) {
526 sctp_bh_lock_sock(sk
);
528 /* If too many ICMPs get dropped on busy
529 * servers this needs to be solved differently.
531 if (sock_owned_by_user(sk
))
532 NET_INC_STATS_BH(net
, LINUX_MIB_LOCKDROPPEDICMPS
);
539 sctp_association_put(asoc
);
543 /* Common cleanup code for icmp/icmpv6 error handler. */
544 void sctp_err_finish(struct sock
*sk
, struct sctp_association
*asoc
)
546 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 const struct iphdr
*iph
= (const 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 __u16 saveip
, savesctp
;
577 struct net
*net
= dev_net(skb
->dev
);
579 if (skb
->len
< ihlen
+ 8) {
580 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
584 /* Fix up skb to look at the embedded net header. */
585 saveip
= skb
->network_header
;
586 savesctp
= skb
->transport_header
;
587 skb_reset_network_header(skb
);
588 skb_set_transport_header(skb
, ihlen
);
589 sk
= sctp_err_lookup(net
, AF_INET
, skb
, sctp_hdr(skb
), &asoc
, &transport
);
590 /* Put back, the original values. */
591 skb
->network_header
= saveip
;
592 skb
->transport_header
= savesctp
;
594 ICMP_INC_STATS_BH(net
, ICMP_MIB_INERRORS
);
597 /* Warning: The sock lock is held. Remember to call
602 case ICMP_PARAMETERPROB
:
605 case ICMP_DEST_UNREACH
:
606 if (code
> NR_ICMP_UNREACH
)
609 /* PMTU discovery (RFC1191) */
610 if (ICMP_FRAG_NEEDED
== code
) {
611 sctp_icmp_frag_needed(sk
, asoc
, transport
, info
);
615 if (ICMP_PROT_UNREACH
== code
) {
616 sctp_icmp_proto_unreachable(sk
, asoc
,
621 err
= icmp_err_convert
[code
].errno
;
623 case ICMP_TIME_EXCEEDED
:
624 /* Ignore any time exceeded errors due to fragment reassembly
627 if (ICMP_EXC_FRAGTIME
== code
)
633 sctp_icmp_redirect(sk
, transport
, skb
);
634 /* Fall through to out_unlock. */
640 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
642 sk
->sk_error_report(sk
);
643 } else { /* Only an error on timeout */
644 sk
->sk_err_soft
= err
;
648 sctp_err_finish(sk
, asoc
);
652 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
654 * This function scans all the chunks in the OOTB packet to determine if
655 * the packet should be discarded right away. If a response might be needed
656 * for this packet, or, if further processing is possible, the packet will
657 * be queued to a proper inqueue for the next phase of handling.
660 * Return 0 - If further processing is needed.
661 * Return 1 - If the packet can be discarded right away.
663 static int sctp_rcv_ootb(struct sk_buff
*skb
)
668 ch
= (sctp_chunkhdr_t
*) skb
->data
;
670 /* Scan through all the chunks in the packet. */
672 /* Break out if chunk length is less then minimal. */
673 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
676 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
677 if (ch_end
> skb_tail_pointer(skb
))
680 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
681 * receiver MUST silently discard the OOTB packet and take no
684 if (SCTP_CID_ABORT
== ch
->type
)
687 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
688 * chunk, the receiver should silently discard the packet
689 * and take no further action.
691 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
695 * This will discard packets with INIT chunk bundled as
696 * subsequent chunks in the packet. When INIT is first,
697 * the normal INIT processing will discard the chunk.
699 if (SCTP_CID_INIT
== ch
->type
&& (void *)ch
!= skb
->data
)
702 ch
= (sctp_chunkhdr_t
*) ch_end
;
703 } while (ch_end
< skb_tail_pointer(skb
));
711 /* Insert endpoint into the hash table. */
712 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
714 struct net
*net
= sock_net(ep
->base
.sk
);
715 struct sctp_ep_common
*epb
;
716 struct sctp_hashbucket
*head
;
720 epb
->hashent
= sctp_ep_hashfn(net
, epb
->bind_addr
.port
);
721 head
= &sctp_ep_hashtable
[epb
->hashent
];
723 sctp_write_lock(&head
->lock
);
724 hlist_add_head(&epb
->node
, &head
->chain
);
725 sctp_write_unlock(&head
->lock
);
728 /* Add an endpoint to the hash. Local BH-safe. */
729 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
731 sctp_local_bh_disable();
732 __sctp_hash_endpoint(ep
);
733 sctp_local_bh_enable();
736 /* Remove endpoint from the hash table. */
737 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
739 struct net
*net
= sock_net(ep
->base
.sk
);
740 struct sctp_hashbucket
*head
;
741 struct sctp_ep_common
*epb
;
745 epb
->hashent
= sctp_ep_hashfn(net
, epb
->bind_addr
.port
);
747 head
= &sctp_ep_hashtable
[epb
->hashent
];
749 sctp_write_lock(&head
->lock
);
750 hlist_del_init(&epb
->node
);
751 sctp_write_unlock(&head
->lock
);
754 /* Remove endpoint from the hash. Local BH-safe. */
755 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
757 sctp_local_bh_disable();
758 __sctp_unhash_endpoint(ep
);
759 sctp_local_bh_enable();
762 /* Look up an endpoint. */
763 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(struct net
*net
,
764 const union sctp_addr
*laddr
)
766 struct sctp_hashbucket
*head
;
767 struct sctp_ep_common
*epb
;
768 struct sctp_endpoint
*ep
;
771 hash
= sctp_ep_hashfn(net
, ntohs(laddr
->v4
.sin_port
));
772 head
= &sctp_ep_hashtable
[hash
];
773 read_lock(&head
->lock
);
774 sctp_for_each_hentry(epb
, &head
->chain
) {
776 if (sctp_endpoint_is_match(ep
, net
, laddr
))
780 ep
= sctp_sk(net
->sctp
.ctl_sock
)->ep
;
783 sctp_endpoint_hold(ep
);
784 read_unlock(&head
->lock
);
788 /* Insert association into the hash table. */
789 static void __sctp_hash_established(struct sctp_association
*asoc
)
791 struct net
*net
= sock_net(asoc
->base
.sk
);
792 struct sctp_ep_common
*epb
;
793 struct sctp_hashbucket
*head
;
797 /* Calculate which chain this entry will belong to. */
798 epb
->hashent
= sctp_assoc_hashfn(net
, epb
->bind_addr
.port
,
801 head
= &sctp_assoc_hashtable
[epb
->hashent
];
803 sctp_write_lock(&head
->lock
);
804 hlist_add_head(&epb
->node
, &head
->chain
);
805 sctp_write_unlock(&head
->lock
);
808 /* Add an association to the hash. Local BH-safe. */
809 void sctp_hash_established(struct sctp_association
*asoc
)
814 sctp_local_bh_disable();
815 __sctp_hash_established(asoc
);
816 sctp_local_bh_enable();
819 /* Remove association from the hash table. */
820 static void __sctp_unhash_established(struct sctp_association
*asoc
)
822 struct net
*net
= sock_net(asoc
->base
.sk
);
823 struct sctp_hashbucket
*head
;
824 struct sctp_ep_common
*epb
;
828 epb
->hashent
= sctp_assoc_hashfn(net
, epb
->bind_addr
.port
,
831 head
= &sctp_assoc_hashtable
[epb
->hashent
];
833 sctp_write_lock(&head
->lock
);
834 hlist_del_init(&epb
->node
);
835 sctp_write_unlock(&head
->lock
);
838 /* Remove association from the hash table. Local BH-safe. */
839 void sctp_unhash_established(struct sctp_association
*asoc
)
844 sctp_local_bh_disable();
845 __sctp_unhash_established(asoc
);
846 sctp_local_bh_enable();
849 /* Look up an association. */
850 static struct sctp_association
*__sctp_lookup_association(
852 const union sctp_addr
*local
,
853 const union sctp_addr
*peer
,
854 struct sctp_transport
**pt
)
856 struct sctp_hashbucket
*head
;
857 struct sctp_ep_common
*epb
;
858 struct sctp_association
*asoc
;
859 struct sctp_transport
*transport
;
862 /* Optimize here for direct hit, only listening connections can
863 * have wildcards anyways.
865 hash
= sctp_assoc_hashfn(net
, ntohs(local
->v4
.sin_port
),
866 ntohs(peer
->v4
.sin_port
));
867 head
= &sctp_assoc_hashtable
[hash
];
868 read_lock(&head
->lock
);
869 sctp_for_each_hentry(epb
, &head
->chain
) {
870 asoc
= sctp_assoc(epb
);
871 transport
= sctp_assoc_is_match(asoc
, net
, local
, peer
);
876 read_unlock(&head
->lock
);
882 sctp_association_hold(asoc
);
883 read_unlock(&head
->lock
);
887 /* Look up an association. BH-safe. */
889 struct sctp_association
*sctp_lookup_association(struct net
*net
,
890 const union sctp_addr
*laddr
,
891 const union sctp_addr
*paddr
,
892 struct sctp_transport
**transportp
)
894 struct sctp_association
*asoc
;
896 sctp_local_bh_disable();
897 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, transportp
);
898 sctp_local_bh_enable();
903 /* Is there an association matching the given local and peer addresses? */
904 int sctp_has_association(struct net
*net
,
905 const union sctp_addr
*laddr
,
906 const union sctp_addr
*paddr
)
908 struct sctp_association
*asoc
;
909 struct sctp_transport
*transport
;
911 if ((asoc
= sctp_lookup_association(net
, laddr
, paddr
, &transport
))) {
912 sctp_association_put(asoc
);
920 * SCTP Implementors Guide, 2.18 Handling of address
921 * parameters within the INIT or INIT-ACK.
923 * D) When searching for a matching TCB upon reception of an INIT
924 * or INIT-ACK chunk the receiver SHOULD use not only the
925 * source address of the packet (containing the INIT or
926 * INIT-ACK) but the receiver SHOULD also use all valid
927 * address parameters contained within the chunk.
929 * 2.18.3 Solution description
931 * This new text clearly specifies to an implementor the need
932 * to look within the INIT or INIT-ACK. Any implementation that
933 * does not do this, may not be able to establish associations
934 * in certain circumstances.
937 static struct sctp_association
*__sctp_rcv_init_lookup(struct net
*net
,
939 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
941 struct sctp_association
*asoc
;
942 union sctp_addr addr
;
943 union sctp_addr
*paddr
= &addr
;
944 struct sctphdr
*sh
= sctp_hdr(skb
);
945 union sctp_params params
;
946 sctp_init_chunk_t
*init
;
947 struct sctp_transport
*transport
;
951 * This code will NOT touch anything inside the chunk--it is
952 * strictly READ-ONLY.
954 * RFC 2960 3 SCTP packet Format
956 * Multiple chunks can be bundled into one SCTP packet up to
957 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
958 * COMPLETE chunks. These chunks MUST NOT be bundled with any
959 * other chunk in a packet. See Section 6.10 for more details
963 /* Find the start of the TLVs and the end of the chunk. This is
964 * the region we search for address parameters.
966 init
= (sctp_init_chunk_t
*)skb
->data
;
968 /* Walk the parameters looking for embedded addresses. */
969 sctp_walk_params(params
, init
, init_hdr
.params
) {
971 /* Note: Ignoring hostname addresses. */
972 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
976 af
->from_addr_param(paddr
, params
.addr
, sh
->source
, 0);
978 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, &transport
);
986 /* ADD-IP, Section 5.2
987 * When an endpoint receives an ASCONF Chunk from the remote peer
988 * special procedures may be needed to identify the association the
989 * ASCONF Chunk is associated with. To properly find the association
990 * the following procedures SHOULD be followed:
992 * D2) If the association is not found, use the address found in the
993 * Address Parameter TLV combined with the port number found in the
994 * SCTP common header. If found proceed to rule D4.
996 * D2-ext) If more than one ASCONF Chunks are packed together, use the
997 * address found in the ASCONF Address Parameter TLV of each of the
998 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1000 static struct sctp_association
*__sctp_rcv_asconf_lookup(
1002 sctp_chunkhdr_t
*ch
,
1003 const union sctp_addr
*laddr
,
1005 struct sctp_transport
**transportp
)
1007 sctp_addip_chunk_t
*asconf
= (struct sctp_addip_chunk
*)ch
;
1009 union sctp_addr_param
*param
;
1010 union sctp_addr paddr
;
1012 /* Skip over the ADDIP header and find the Address parameter */
1013 param
= (union sctp_addr_param
*)(asconf
+ 1);
1015 af
= sctp_get_af_specific(param_type2af(param
->p
.type
));
1019 af
->from_addr_param(&paddr
, param
, peer_port
, 0);
1021 return __sctp_lookup_association(net
, laddr
, &paddr
, transportp
);
1025 /* SCTP-AUTH, Section 6.3:
1026 * If the receiver does not find a STCB for a packet containing an AUTH
1027 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1028 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1031 * This means that any chunks that can help us identify the association need
1032 * to be looked at to find this association.
1034 static struct sctp_association
*__sctp_rcv_walk_lookup(struct net
*net
,
1035 struct sk_buff
*skb
,
1036 const union sctp_addr
*laddr
,
1037 struct sctp_transport
**transportp
)
1039 struct sctp_association
*asoc
= NULL
;
1040 sctp_chunkhdr_t
*ch
;
1042 unsigned int chunk_num
= 1;
1045 /* Walk through the chunks looking for AUTH or ASCONF chunks
1046 * to help us find the association.
1048 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1050 /* Break out if chunk length is less then minimal. */
1051 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
1054 ch_end
= ((__u8
*)ch
) + WORD_ROUND(ntohs(ch
->length
));
1055 if (ch_end
> skb_tail_pointer(skb
))
1060 have_auth
= chunk_num
;
1063 case SCTP_CID_COOKIE_ECHO
:
1064 /* If a packet arrives containing an AUTH chunk as
1065 * a first chunk, a COOKIE-ECHO chunk as the second
1066 * chunk, and possibly more chunks after them, and
1067 * the receiver does not have an STCB for that
1068 * packet, then authentication is based on
1069 * the contents of the COOKIE- ECHO chunk.
1071 if (have_auth
== 1 && chunk_num
== 2)
1075 case SCTP_CID_ASCONF
:
1076 if (have_auth
|| net
->sctp
.addip_noauth
)
1077 asoc
= __sctp_rcv_asconf_lookup(
1079 sctp_hdr(skb
)->source
,
1088 ch
= (sctp_chunkhdr_t
*) ch_end
;
1090 } while (ch_end
< skb_tail_pointer(skb
));
1096 * There are circumstances when we need to look inside the SCTP packet
1097 * for information to help us find the association. Examples
1098 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1101 static struct sctp_association
*__sctp_rcv_lookup_harder(struct net
*net
,
1102 struct sk_buff
*skb
,
1103 const union sctp_addr
*laddr
,
1104 struct sctp_transport
**transportp
)
1106 sctp_chunkhdr_t
*ch
;
1108 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1110 /* The code below will attempt to walk the chunk and extract
1111 * parameter information. Before we do that, we need to verify
1112 * that the chunk length doesn't cause overflow. Otherwise, we'll
1115 if (WORD_ROUND(ntohs(ch
->length
)) > skb
->len
)
1118 /* If this is INIT/INIT-ACK look inside the chunk too. */
1119 if (ch
->type
== SCTP_CID_INIT
|| ch
->type
== SCTP_CID_INIT_ACK
)
1120 return __sctp_rcv_init_lookup(net
, skb
, laddr
, transportp
);
1122 return __sctp_rcv_walk_lookup(net
, skb
, laddr
, transportp
);
1125 /* Lookup an association for an inbound skb. */
1126 static struct sctp_association
*__sctp_rcv_lookup(struct net
*net
,
1127 struct sk_buff
*skb
,
1128 const union sctp_addr
*paddr
,
1129 const union sctp_addr
*laddr
,
1130 struct sctp_transport
**transportp
)
1132 struct sctp_association
*asoc
;
1134 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, transportp
);
1136 /* Further lookup for INIT/INIT-ACK packets.
1137 * SCTP Implementors Guide, 2.18 Handling of address
1138 * parameters within the INIT or INIT-ACK.
1141 asoc
= __sctp_rcv_lookup_harder(net
, skb
, laddr
, transportp
);