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(net
, SCTP_MIB_CHECKSUMERRORS
);
94 * This is the routine which IP calls when receiving an SCTP packet.
96 int sctp_rcv(struct sk_buff
*skb
)
99 struct sctp_association
*asoc
;
100 struct sctp_endpoint
*ep
= NULL
;
101 struct sctp_ep_common
*rcvr
;
102 struct sctp_transport
*transport
= NULL
;
103 struct sctp_chunk
*chunk
;
105 union sctp_addr dest
;
108 struct net
*net
= dev_net(skb
->dev
);
110 if (skb
->pkt_type
!= PACKET_HOST
)
113 __SCTP_INC_STATS(net
, SCTP_MIB_INSCTPPACKS
);
115 /* If packet is too small to contain a single chunk, let's not
116 * waste time on it anymore.
118 if (skb
->len
< sizeof(struct sctphdr
) + sizeof(struct sctp_chunkhdr
) +
119 skb_transport_offset(skb
))
122 /* If the packet is fragmented and we need to do crc checking,
123 * it's better to just linearize it otherwise crc computing
126 if ((!(skb_shinfo(skb
)->gso_type
& SKB_GSO_SCTP
) &&
127 skb_linearize(skb
)) ||
128 !pskb_may_pull(skb
, sizeof(struct sctphdr
)))
131 /* Pull up the IP header. */
132 __skb_pull(skb
, skb_transport_offset(skb
));
134 skb
->csum_valid
= 0; /* Previous value not applicable */
135 if (skb_csum_unnecessary(skb
))
136 __skb_decr_checksum_unnecessary(skb
);
137 else if (!sctp_checksum_disable
&&
138 !(skb_shinfo(skb
)->gso_type
& SKB_GSO_SCTP
) &&
139 sctp_rcv_checksum(net
, skb
) < 0)
143 __skb_pull(skb
, sizeof(struct sctphdr
));
145 family
= ipver2af(ip_hdr(skb
)->version
);
146 af
= sctp_get_af_specific(family
);
149 SCTP_INPUT_CB(skb
)->af
= af
;
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
))) {
185 sctp_transport_put(transport
);
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(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
, GFP_ATOMIC
);
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
= sctp_hdr(skb
);
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.
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
257 if (sock_owned_by_user(sk
)) {
258 if (sctp_add_backlog(sk
, skb
)) {
260 sctp_chunk_free(chunk
);
261 skb
= NULL
; /* sctp_chunk_free already freed the skb */
262 goto discard_release
;
264 __SCTP_INC_STATS(net
, SCTP_MIB_IN_PKT_BACKLOG
);
266 __SCTP_INC_STATS(net
, SCTP_MIB_IN_PKT_SOFTIRQ
);
267 sctp_inq_push(&chunk
->rcvr
->inqueue
, chunk
);
272 /* Release the asoc/ep ref we took in the lookup calls. */
274 sctp_transport_put(transport
);
276 sctp_endpoint_put(ep
);
281 __SCTP_INC_STATS(net
, SCTP_MIB_IN_PKT_DISCARDS
);
286 /* Release the asoc/ep ref we took in the lookup calls. */
288 sctp_transport_put(transport
);
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_transport
*t
= chunk
->transport
;
305 struct sctp_ep_common
*rcvr
= NULL
;
310 /* If the rcvr is dead then the association or endpoint
311 * has been deleted and we can safely drop the chunk
312 * and refs that we are holding.
315 sctp_chunk_free(chunk
);
319 if (unlikely(rcvr
->sk
!= sk
)) {
320 /* In this case, the association moved from one socket to
321 * another. We are currently sitting on the backlog of the
322 * old socket, so we need to move.
323 * However, since we are here in the process context we
324 * need to take make sure that the user doesn't own
325 * the new socket when we process the packet.
326 * If the new socket is user-owned, queue the chunk to the
327 * backlog of the new socket without dropping any refs.
328 * Otherwise, we can safely push the chunk on the inqueue.
335 if (sock_owned_by_user(sk
)) {
336 if (sk_add_backlog(sk
, skb
, sk
->sk_rcvbuf
))
337 sctp_chunk_free(chunk
);
341 sctp_inq_push(inqueue
, chunk
);
346 /* If the chunk was backloged again, don't drop refs */
350 sctp_inq_push(inqueue
, chunk
);
354 /* Release the refs we took in sctp_add_backlog */
355 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
356 sctp_transport_put(t
);
357 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
358 sctp_endpoint_put(sctp_ep(rcvr
));
365 static int sctp_add_backlog(struct sock
*sk
, struct sk_buff
*skb
)
367 struct sctp_chunk
*chunk
= SCTP_INPUT_CB(skb
)->chunk
;
368 struct sctp_transport
*t
= chunk
->transport
;
369 struct sctp_ep_common
*rcvr
= chunk
->rcvr
;
372 ret
= sk_add_backlog(sk
, skb
, sk
->sk_rcvbuf
);
374 /* Hold the assoc/ep while hanging on the backlog queue.
375 * This way, we know structures we need will not disappear
378 if (SCTP_EP_TYPE_ASSOCIATION
== rcvr
->type
)
379 sctp_transport_hold(t
);
380 else if (SCTP_EP_TYPE_SOCKET
== rcvr
->type
)
381 sctp_endpoint_hold(sctp_ep(rcvr
));
389 /* Handle icmp frag needed error. */
390 void sctp_icmp_frag_needed(struct sock
*sk
, struct sctp_association
*asoc
,
391 struct sctp_transport
*t
, __u32 pmtu
)
393 if (!t
|| (t
->pathmtu
<= pmtu
))
396 if (sock_owned_by_user(sk
)) {
397 asoc
->pmtu_pending
= 1;
402 if (t
->param_flags
& SPP_PMTUD_ENABLE
) {
403 /* Update transports view of the MTU */
404 sctp_transport_update_pmtu(sk
, t
, pmtu
);
406 /* Update association pmtu. */
407 sctp_assoc_sync_pmtu(sk
, asoc
);
410 /* Retransmit with the new pmtu setting.
411 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
412 * Needed will never be sent, but if a message was sent before
413 * PMTU discovery was disabled that was larger than the PMTU, it
414 * would not be fragmented, so it must be re-transmitted fragmented.
416 sctp_retransmit(&asoc
->outqueue
, t
, SCTP_RTXR_PMTUD
);
419 void sctp_icmp_redirect(struct sock
*sk
, struct sctp_transport
*t
,
422 struct dst_entry
*dst
;
426 dst
= sctp_transport_dst_check(t
);
428 dst
->ops
->redirect(dst
, sk
, skb
);
432 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
434 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
435 * or a "Protocol Unreachable" treat this message as an abort
436 * with the T bit set.
438 * This function sends an event to the state machine, which will abort the
442 void sctp_icmp_proto_unreachable(struct sock
*sk
,
443 struct sctp_association
*asoc
,
444 struct sctp_transport
*t
)
446 if (sock_owned_by_user(sk
)) {
447 if (timer_pending(&t
->proto_unreach_timer
))
450 if (!mod_timer(&t
->proto_unreach_timer
,
452 sctp_association_hold(asoc
);
455 struct net
*net
= sock_net(sk
);
457 pr_debug("%s: unrecognized next header type "
458 "encountered!\n", __func__
);
460 if (del_timer(&t
->proto_unreach_timer
))
461 sctp_association_put(asoc
);
463 sctp_do_sm(net
, SCTP_EVENT_T_OTHER
,
464 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH
),
465 asoc
->state
, asoc
->ep
, asoc
, t
,
470 /* Common lookup code for icmp/icmpv6 error handler. */
471 struct sock
*sctp_err_lookup(struct net
*net
, int family
, struct sk_buff
*skb
,
472 struct sctphdr
*sctphdr
,
473 struct sctp_association
**app
,
474 struct sctp_transport
**tpp
)
476 union sctp_addr saddr
;
477 union sctp_addr daddr
;
479 struct sock
*sk
= NULL
;
480 struct sctp_association
*asoc
;
481 struct sctp_transport
*transport
= NULL
;
482 struct sctp_init_chunk
*chunkhdr
;
483 __u32 vtag
= ntohl(sctphdr
->vtag
);
484 int len
= skb
->len
- ((void *)sctphdr
- (void *)skb
->data
);
486 *app
= NULL
; *tpp
= NULL
;
488 af
= sctp_get_af_specific(family
);
493 /* Initialize local addresses for lookups. */
494 af
->from_skb(&saddr
, skb
, 1);
495 af
->from_skb(&daddr
, skb
, 0);
497 /* Look for an association that matches the incoming ICMP error
500 asoc
= __sctp_lookup_association(net
, &saddr
, &daddr
, &transport
);
506 /* RFC 4960, Appendix C. ICMP Handling
508 * ICMP6) An implementation MUST validate that the Verification Tag
509 * contained in the ICMP message matches the Verification Tag of
510 * the peer. If the Verification Tag is not 0 and does NOT
511 * match, discard the ICMP message. If it is 0 and the ICMP
512 * message contains enough bytes to verify that the chunk type is
513 * an INIT chunk and that the Initiate Tag matches the tag of the
514 * peer, continue with ICMP7. If the ICMP message is too short
515 * or the chunk type or the Initiate Tag does not match, silently
516 * discard the packet.
519 chunkhdr
= (void *)sctphdr
+ sizeof(struct sctphdr
);
520 if (len
< sizeof(struct sctphdr
) + sizeof(sctp_chunkhdr_t
)
522 chunkhdr
->chunk_hdr
.type
!= SCTP_CID_INIT
||
523 ntohl(chunkhdr
->init_hdr
.init_tag
) != asoc
->c
.my_vtag
) {
526 } else if (vtag
!= asoc
->c
.peer_vtag
) {
532 /* If too many ICMPs get dropped on busy
533 * servers this needs to be solved differently.
535 if (sock_owned_by_user(sk
))
536 __NET_INC_STATS(net
, LINUX_MIB_LOCKDROPPEDICMPS
);
543 sctp_transport_put(transport
);
547 /* Common cleanup code for icmp/icmpv6 error handler. */
548 void sctp_err_finish(struct sock
*sk
, struct sctp_transport
*t
)
551 sctp_transport_put(t
);
555 * This routine is called by the ICMP module when it gets some
556 * sort of error condition. If err < 0 then the socket should
557 * be closed and the error returned to the user. If err > 0
558 * it's just the icmp type << 8 | icmp code. After adjustment
559 * header points to the first 8 bytes of the sctp header. We need
560 * to find the appropriate port.
562 * The locking strategy used here is very "optimistic". When
563 * someone else accesses the socket the ICMP is just dropped
564 * and for some paths there is no check at all.
565 * A more general error queue to queue errors for later handling
566 * is probably better.
569 void sctp_v4_err(struct sk_buff
*skb
, __u32 info
)
571 const struct iphdr
*iph
= (const struct iphdr
*)skb
->data
;
572 const int ihlen
= iph
->ihl
* 4;
573 const int type
= icmp_hdr(skb
)->type
;
574 const int code
= icmp_hdr(skb
)->code
;
576 struct sctp_association
*asoc
= NULL
;
577 struct sctp_transport
*transport
;
578 struct inet_sock
*inet
;
579 __u16 saveip
, savesctp
;
581 struct net
*net
= dev_net(skb
->dev
);
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(net
, 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(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
,
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
)
632 sctp_icmp_redirect(sk
, transport
, skb
);
633 /* Fall through to out_unlock. */
639 if (!sock_owned_by_user(sk
) && inet
->recverr
) {
641 sk
->sk_error_report(sk
);
642 } else { /* Only an error on timeout */
643 sk
->sk_err_soft
= err
;
647 sctp_err_finish(sk
, transport
);
651 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
653 * This function scans all the chunks in the OOTB packet to determine if
654 * the packet should be discarded right away. If a response might be needed
655 * for this packet, or, if further processing is possible, the packet will
656 * be queued to a proper inqueue for the next phase of handling.
659 * Return 0 - If further processing is needed.
660 * Return 1 - If the packet can be discarded right away.
662 static int sctp_rcv_ootb(struct sk_buff
*skb
)
664 sctp_chunkhdr_t
*ch
, _ch
;
665 int ch_end
, offset
= 0;
667 /* Scan through all the chunks in the packet. */
669 /* Make sure we have at least the header there */
670 if (offset
+ sizeof(sctp_chunkhdr_t
) > skb
->len
)
673 ch
= skb_header_pointer(skb
, offset
, sizeof(*ch
), &_ch
);
675 /* Break out if chunk length is less then minimal. */
676 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
679 ch_end
= offset
+ SCTP_PAD4(ntohs(ch
->length
));
680 if (ch_end
> skb
->len
)
683 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
684 * receiver MUST silently discard the OOTB packet and take no
687 if (SCTP_CID_ABORT
== ch
->type
)
690 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
691 * chunk, the receiver should silently discard the packet
692 * and take no further action.
694 if (SCTP_CID_SHUTDOWN_COMPLETE
== ch
->type
)
698 * This will discard packets with INIT chunk bundled as
699 * subsequent chunks in the packet. When INIT is first,
700 * the normal INIT processing will discard the chunk.
702 if (SCTP_CID_INIT
== ch
->type
&& (void *)ch
!= skb
->data
)
706 } while (ch_end
< skb
->len
);
714 /* Insert endpoint into the hash table. */
715 static void __sctp_hash_endpoint(struct sctp_endpoint
*ep
)
717 struct net
*net
= sock_net(ep
->base
.sk
);
718 struct sctp_ep_common
*epb
;
719 struct sctp_hashbucket
*head
;
723 epb
->hashent
= sctp_ep_hashfn(net
, epb
->bind_addr
.port
);
724 head
= &sctp_ep_hashtable
[epb
->hashent
];
726 write_lock(&head
->lock
);
727 hlist_add_head(&epb
->node
, &head
->chain
);
728 write_unlock(&head
->lock
);
731 /* Add an endpoint to the hash. Local BH-safe. */
732 void sctp_hash_endpoint(struct sctp_endpoint
*ep
)
735 __sctp_hash_endpoint(ep
);
739 /* Remove endpoint from the hash table. */
740 static void __sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
742 struct net
*net
= sock_net(ep
->base
.sk
);
743 struct sctp_hashbucket
*head
;
744 struct sctp_ep_common
*epb
;
748 epb
->hashent
= sctp_ep_hashfn(net
, epb
->bind_addr
.port
);
750 head
= &sctp_ep_hashtable
[epb
->hashent
];
752 write_lock(&head
->lock
);
753 hlist_del_init(&epb
->node
);
754 write_unlock(&head
->lock
);
757 /* Remove endpoint from the hash. Local BH-safe. */
758 void sctp_unhash_endpoint(struct sctp_endpoint
*ep
)
761 __sctp_unhash_endpoint(ep
);
765 /* Look up an endpoint. */
766 static struct sctp_endpoint
*__sctp_rcv_lookup_endpoint(struct net
*net
,
767 const union sctp_addr
*laddr
)
769 struct sctp_hashbucket
*head
;
770 struct sctp_ep_common
*epb
;
771 struct sctp_endpoint
*ep
;
774 hash
= sctp_ep_hashfn(net
, ntohs(laddr
->v4
.sin_port
));
775 head
= &sctp_ep_hashtable
[hash
];
776 read_lock(&head
->lock
);
777 sctp_for_each_hentry(epb
, &head
->chain
) {
779 if (sctp_endpoint_is_match(ep
, net
, laddr
))
783 ep
= sctp_sk(net
->sctp
.ctl_sock
)->ep
;
786 sctp_endpoint_hold(ep
);
787 read_unlock(&head
->lock
);
791 /* rhashtable for transport */
792 struct sctp_hash_cmp_arg
{
793 const union sctp_addr
*paddr
;
794 const struct net
*net
;
798 static inline int sctp_hash_cmp(struct rhashtable_compare_arg
*arg
,
801 struct sctp_transport
*t
= (struct sctp_transport
*)ptr
;
802 const struct sctp_hash_cmp_arg
*x
= arg
->key
;
805 if (!sctp_cmp_addr_exact(&t
->ipaddr
, x
->paddr
))
807 if (!sctp_transport_hold(t
))
810 if (!net_eq(sock_net(t
->asoc
->base
.sk
), x
->net
))
812 if (x
->lport
!= htons(t
->asoc
->base
.bind_addr
.port
))
817 sctp_transport_put(t
);
821 static inline u32
sctp_hash_obj(const void *data
, u32 len
, u32 seed
)
823 const struct sctp_transport
*t
= data
;
824 const union sctp_addr
*paddr
= &t
->ipaddr
;
825 const struct net
*net
= sock_net(t
->asoc
->base
.sk
);
826 u16 lport
= htons(t
->asoc
->base
.bind_addr
.port
);
829 if (paddr
->sa
.sa_family
== AF_INET6
)
830 addr
= jhash(&paddr
->v6
.sin6_addr
, 16, seed
);
832 addr
= paddr
->v4
.sin_addr
.s_addr
;
834 return jhash_3words(addr
, ((__u32
)paddr
->v4
.sin_port
) << 16 |
835 (__force __u32
)lport
, net_hash_mix(net
), seed
);
838 static inline u32
sctp_hash_key(const void *data
, u32 len
, u32 seed
)
840 const struct sctp_hash_cmp_arg
*x
= data
;
841 const union sctp_addr
*paddr
= x
->paddr
;
842 const struct net
*net
= x
->net
;
843 u16 lport
= x
->lport
;
846 if (paddr
->sa
.sa_family
== AF_INET6
)
847 addr
= jhash(&paddr
->v6
.sin6_addr
, 16, seed
);
849 addr
= paddr
->v4
.sin_addr
.s_addr
;
851 return jhash_3words(addr
, ((__u32
)paddr
->v4
.sin_port
) << 16 |
852 (__force __u32
)lport
, net_hash_mix(net
), seed
);
855 static const struct rhashtable_params sctp_hash_params
= {
856 .head_offset
= offsetof(struct sctp_transport
, node
),
857 .hashfn
= sctp_hash_key
,
858 .obj_hashfn
= sctp_hash_obj
,
859 .obj_cmpfn
= sctp_hash_cmp
,
860 .automatic_shrinking
= true,
863 int sctp_transport_hashtable_init(void)
865 return rhltable_init(&sctp_transport_hashtable
, &sctp_hash_params
);
868 void sctp_transport_hashtable_destroy(void)
870 rhltable_destroy(&sctp_transport_hashtable
);
873 int sctp_hash_transport(struct sctp_transport
*t
)
875 struct sctp_transport
*transport
;
876 struct rhlist_head
*tmp
, *list
;
877 struct sctp_hash_cmp_arg arg
;
883 arg
.net
= sock_net(t
->asoc
->base
.sk
);
884 arg
.paddr
= &t
->ipaddr
;
885 arg
.lport
= htons(t
->asoc
->base
.bind_addr
.port
);
888 list
= rhltable_lookup(&sctp_transport_hashtable
, &arg
,
891 rhl_for_each_entry_rcu(transport
, tmp
, list
, node
)
892 if (transport
->asoc
->ep
== t
->asoc
->ep
) {
899 err
= rhltable_insert_key(&sctp_transport_hashtable
, &arg
,
900 &t
->node
, sctp_hash_params
);
904 pr_err_once("insert transport fail, errno %d\n", err
);
909 void sctp_unhash_transport(struct sctp_transport
*t
)
914 rhltable_remove(&sctp_transport_hashtable
, &t
->node
,
918 /* return a transport with holding it */
919 struct sctp_transport
*sctp_addrs_lookup_transport(
921 const union sctp_addr
*laddr
,
922 const union sctp_addr
*paddr
)
924 struct rhlist_head
*tmp
, *list
;
925 struct sctp_transport
*t
;
926 struct sctp_hash_cmp_arg arg
= {
929 .lport
= laddr
->v4
.sin_port
,
932 list
= rhltable_lookup(&sctp_transport_hashtable
, &arg
,
935 rhl_for_each_entry_rcu(t
, tmp
, list
, node
) {
936 if (!sctp_transport_hold(t
))
939 if (sctp_bind_addr_match(&t
->asoc
->base
.bind_addr
,
940 laddr
, sctp_sk(t
->asoc
->base
.sk
)))
942 sctp_transport_put(t
);
948 /* return a transport without holding it, as it's only used under sock lock */
949 struct sctp_transport
*sctp_epaddr_lookup_transport(
950 const struct sctp_endpoint
*ep
,
951 const union sctp_addr
*paddr
)
953 struct net
*net
= sock_net(ep
->base
.sk
);
954 struct rhlist_head
*tmp
, *list
;
955 struct sctp_transport
*t
;
956 struct sctp_hash_cmp_arg arg
= {
959 .lport
= htons(ep
->base
.bind_addr
.port
),
962 list
= rhltable_lookup(&sctp_transport_hashtable
, &arg
,
965 rhl_for_each_entry_rcu(t
, tmp
, list
, node
)
966 if (ep
== t
->asoc
->ep
)
972 /* Look up an association. */
973 static struct sctp_association
*__sctp_lookup_association(
975 const union sctp_addr
*local
,
976 const union sctp_addr
*peer
,
977 struct sctp_transport
**pt
)
979 struct sctp_transport
*t
;
980 struct sctp_association
*asoc
= NULL
;
982 t
= sctp_addrs_lookup_transport(net
, local
, peer
);
993 /* Look up an association. protected by RCU read lock */
995 struct sctp_association
*sctp_lookup_association(struct net
*net
,
996 const union sctp_addr
*laddr
,
997 const union sctp_addr
*paddr
,
998 struct sctp_transport
**transportp
)
1000 struct sctp_association
*asoc
;
1003 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, transportp
);
1009 /* Is there an association matching the given local and peer addresses? */
1010 int sctp_has_association(struct net
*net
,
1011 const union sctp_addr
*laddr
,
1012 const union sctp_addr
*paddr
)
1014 struct sctp_association
*asoc
;
1015 struct sctp_transport
*transport
;
1017 if ((asoc
= sctp_lookup_association(net
, laddr
, paddr
, &transport
))) {
1018 sctp_transport_put(transport
);
1026 * SCTP Implementors Guide, 2.18 Handling of address
1027 * parameters within the INIT or INIT-ACK.
1029 * D) When searching for a matching TCB upon reception of an INIT
1030 * or INIT-ACK chunk the receiver SHOULD use not only the
1031 * source address of the packet (containing the INIT or
1032 * INIT-ACK) but the receiver SHOULD also use all valid
1033 * address parameters contained within the chunk.
1035 * 2.18.3 Solution description
1037 * This new text clearly specifies to an implementor the need
1038 * to look within the INIT or INIT-ACK. Any implementation that
1039 * does not do this, may not be able to establish associations
1040 * in certain circumstances.
1043 static struct sctp_association
*__sctp_rcv_init_lookup(struct net
*net
,
1044 struct sk_buff
*skb
,
1045 const union sctp_addr
*laddr
, struct sctp_transport
**transportp
)
1047 struct sctp_association
*asoc
;
1048 union sctp_addr addr
;
1049 union sctp_addr
*paddr
= &addr
;
1050 struct sctphdr
*sh
= sctp_hdr(skb
);
1051 union sctp_params params
;
1052 sctp_init_chunk_t
*init
;
1056 * This code will NOT touch anything inside the chunk--it is
1057 * strictly READ-ONLY.
1059 * RFC 2960 3 SCTP packet Format
1061 * Multiple chunks can be bundled into one SCTP packet up to
1062 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
1063 * COMPLETE chunks. These chunks MUST NOT be bundled with any
1064 * other chunk in a packet. See Section 6.10 for more details
1065 * on chunk bundling.
1068 /* Find the start of the TLVs and the end of the chunk. This is
1069 * the region we search for address parameters.
1071 init
= (sctp_init_chunk_t
*)skb
->data
;
1073 /* Walk the parameters looking for embedded addresses. */
1074 sctp_walk_params(params
, init
, init_hdr
.params
) {
1076 /* Note: Ignoring hostname addresses. */
1077 af
= sctp_get_af_specific(param_type2af(params
.p
->type
));
1081 af
->from_addr_param(paddr
, params
.addr
, sh
->source
, 0);
1083 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, transportp
);
1091 /* ADD-IP, Section 5.2
1092 * When an endpoint receives an ASCONF Chunk from the remote peer
1093 * special procedures may be needed to identify the association the
1094 * ASCONF Chunk is associated with. To properly find the association
1095 * the following procedures SHOULD be followed:
1097 * D2) If the association is not found, use the address found in the
1098 * Address Parameter TLV combined with the port number found in the
1099 * SCTP common header. If found proceed to rule D4.
1101 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1102 * address found in the ASCONF Address Parameter TLV of each of the
1103 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1105 static struct sctp_association
*__sctp_rcv_asconf_lookup(
1107 sctp_chunkhdr_t
*ch
,
1108 const union sctp_addr
*laddr
,
1110 struct sctp_transport
**transportp
)
1112 sctp_addip_chunk_t
*asconf
= (struct sctp_addip_chunk
*)ch
;
1114 union sctp_addr_param
*param
;
1115 union sctp_addr paddr
;
1117 /* Skip over the ADDIP header and find the Address parameter */
1118 param
= (union sctp_addr_param
*)(asconf
+ 1);
1120 af
= sctp_get_af_specific(param_type2af(param
->p
.type
));
1124 af
->from_addr_param(&paddr
, param
, peer_port
, 0);
1126 return __sctp_lookup_association(net
, laddr
, &paddr
, transportp
);
1130 /* SCTP-AUTH, Section 6.3:
1131 * If the receiver does not find a STCB for a packet containing an AUTH
1132 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1133 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1136 * This means that any chunks that can help us identify the association need
1137 * to be looked at to find this association.
1139 static struct sctp_association
*__sctp_rcv_walk_lookup(struct net
*net
,
1140 struct sk_buff
*skb
,
1141 const union sctp_addr
*laddr
,
1142 struct sctp_transport
**transportp
)
1144 struct sctp_association
*asoc
= NULL
;
1145 sctp_chunkhdr_t
*ch
;
1147 unsigned int chunk_num
= 1;
1150 /* Walk through the chunks looking for AUTH or ASCONF chunks
1151 * to help us find the association.
1153 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1155 /* Break out if chunk length is less then minimal. */
1156 if (ntohs(ch
->length
) < sizeof(sctp_chunkhdr_t
))
1159 ch_end
= ((__u8
*)ch
) + SCTP_PAD4(ntohs(ch
->length
));
1160 if (ch_end
> skb_tail_pointer(skb
))
1165 have_auth
= chunk_num
;
1168 case SCTP_CID_COOKIE_ECHO
:
1169 /* If a packet arrives containing an AUTH chunk as
1170 * a first chunk, a COOKIE-ECHO chunk as the second
1171 * chunk, and possibly more chunks after them, and
1172 * the receiver does not have an STCB for that
1173 * packet, then authentication is based on
1174 * the contents of the COOKIE- ECHO chunk.
1176 if (have_auth
== 1 && chunk_num
== 2)
1180 case SCTP_CID_ASCONF
:
1181 if (have_auth
|| net
->sctp
.addip_noauth
)
1182 asoc
= __sctp_rcv_asconf_lookup(
1184 sctp_hdr(skb
)->source
,
1193 ch
= (sctp_chunkhdr_t
*) ch_end
;
1195 } while (ch_end
< skb_tail_pointer(skb
));
1201 * There are circumstances when we need to look inside the SCTP packet
1202 * for information to help us find the association. Examples
1203 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1206 static struct sctp_association
*__sctp_rcv_lookup_harder(struct net
*net
,
1207 struct sk_buff
*skb
,
1208 const union sctp_addr
*laddr
,
1209 struct sctp_transport
**transportp
)
1211 sctp_chunkhdr_t
*ch
;
1213 /* We do not allow GSO frames here as we need to linearize and
1214 * then cannot guarantee frame boundaries. This shouldn't be an
1215 * issue as packets hitting this are mostly INIT or INIT-ACK and
1216 * those cannot be on GSO-style anyway.
1218 if ((skb_shinfo(skb
)->gso_type
& SKB_GSO_SCTP
) == SKB_GSO_SCTP
)
1221 ch
= (sctp_chunkhdr_t
*) skb
->data
;
1223 /* The code below will attempt to walk the chunk and extract
1224 * parameter information. Before we do that, we need to verify
1225 * that the chunk length doesn't cause overflow. Otherwise, we'll
1228 if (SCTP_PAD4(ntohs(ch
->length
)) > skb
->len
)
1231 /* If this is INIT/INIT-ACK look inside the chunk too. */
1232 if (ch
->type
== SCTP_CID_INIT
|| ch
->type
== SCTP_CID_INIT_ACK
)
1233 return __sctp_rcv_init_lookup(net
, skb
, laddr
, transportp
);
1235 return __sctp_rcv_walk_lookup(net
, skb
, laddr
, transportp
);
1238 /* Lookup an association for an inbound skb. */
1239 static struct sctp_association
*__sctp_rcv_lookup(struct net
*net
,
1240 struct sk_buff
*skb
,
1241 const union sctp_addr
*paddr
,
1242 const union sctp_addr
*laddr
,
1243 struct sctp_transport
**transportp
)
1245 struct sctp_association
*asoc
;
1247 asoc
= __sctp_lookup_association(net
, laddr
, paddr
, transportp
);
1251 /* Further lookup for INIT/INIT-ACK packets.
1252 * SCTP Implementors Guide, 2.18 Handling of address
1253 * parameters within the INIT or INIT-ACK.
1255 asoc
= __sctp_rcv_lookup_harder(net
, skb
, laddr
, transportp
);
1259 if (paddr
->sa
.sa_family
== AF_INET
)
1260 pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n",
1261 &laddr
->v4
.sin_addr
, ntohs(laddr
->v4
.sin_port
),
1262 &paddr
->v4
.sin_addr
, ntohs(paddr
->v4
.sin_port
));
1264 pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n",
1265 &laddr
->v6
.sin6_addr
, ntohs(laddr
->v6
.sin6_port
),
1266 &paddr
->v6
.sin6_addr
, ntohs(paddr
->v6
.sin6_port
));