1 /* SCTP kernel reference 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 reference Implementation
11 * These functions handle all input from the IP layer into SCTP.
13 * The SCTP reference 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 * The SCTP reference 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>
64 /* Forward declarations for internal helpers. */
65 static int sctp_rcv_ootb(struct sk_buff *);
66 static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
67 const union sctp_addr *laddr,
68 const union sctp_addr *paddr,
69 struct sctp_transport **transportp);
70 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr);
71 static struct sctp_association *__sctp_lookup_association(
72 const union sctp_addr *local,
73 const union sctp_addr *peer,
74 struct sctp_transport **pt);
76 static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
79 /* Calculate the SCTP checksum of an SCTP packet. */
80 static inline int sctp_rcv_checksum(struct sk_buff *skb)
84 struct sk_buff *list = skb_shinfo(skb)->frag_list;
86 sh = (struct sctphdr *) skb->h.raw;
87 cmp = ntohl(sh->checksum);
89 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
91 for (; list; list = list->next)
92 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
95 val = sctp_end_cksum(val);
98 /* CRC failure, dump it. */
99 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS);
105 struct sctp_input_cb {
107 struct inet_skb_parm h4;
108 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
109 struct inet6_skb_parm h6;
112 struct sctp_chunk *chunk;
114 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
117 * This is the routine which IP calls when receiving an SCTP packet.
119 int sctp_rcv(struct sk_buff *skb)
122 struct sctp_association *asoc;
123 struct sctp_endpoint *ep = NULL;
124 struct sctp_ep_common *rcvr;
125 struct sctp_transport *transport = NULL;
126 struct sctp_chunk *chunk;
129 union sctp_addr dest;
133 if (skb->pkt_type!=PACKET_HOST)
136 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
138 sh = (struct sctphdr *) skb->h.raw;
140 /* Pull up the IP and SCTP headers. */
141 __skb_pull(skb, skb->h.raw - skb->data);
142 if (skb->len < sizeof(struct sctphdr))
144 if ((skb->ip_summed != CHECKSUM_UNNECESSARY) &&
145 (sctp_rcv_checksum(skb) < 0))
148 skb_pull(skb, sizeof(struct sctphdr));
150 /* Make sure we at least have chunk headers worth of data left. */
151 if (skb->len < sizeof(struct sctp_chunkhdr))
154 family = ipver2af(skb->nh.iph->version);
155 af = sctp_get_af_specific(family);
159 /* Initialize local addresses for lookups. */
160 af->from_skb(&src, skb, 1);
161 af->from_skb(&dest, skb, 0);
163 /* If the packet is to or from a non-unicast address,
164 * silently discard the packet.
166 * This is not clearly defined in the RFC except in section
167 * 8.4 - OOTB handling. However, based on the book "Stream Control
168 * Transmission Protocol" 2.1, "It is important to note that the
169 * IP address of an SCTP transport address must be a routable
170 * unicast address. In other words, IP multicast addresses and
171 * IP broadcast addresses cannot be used in an SCTP transport
174 if (!af->addr_valid(&src, NULL, skb) ||
175 !af->addr_valid(&dest, NULL, skb))
178 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
181 ep = __sctp_rcv_lookup_endpoint(&dest);
183 /* Retrieve the common input handling substructure. */
184 rcvr = asoc ? &asoc->base : &ep->base;
188 * If a frame arrives on an interface and the receiving socket is
189 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
191 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
194 sctp_association_put(asoc);
197 sctp_endpoint_put(ep);
200 sk = sctp_get_ctl_sock();
201 ep = sctp_sk(sk)->ep;
202 sctp_endpoint_hold(ep);
207 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
208 * An SCTP packet is called an "out of the blue" (OOTB)
209 * packet if it is correctly formed, i.e., passed the
210 * receiver's checksum check, but the receiver is not
211 * able to identify the association to which this
215 if (sctp_rcv_ootb(skb)) {
216 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
217 goto discard_release;
221 /* SCTP seems to always need a timestamp right now (FIXME) */
222 if (skb->tstamp.off_sec == 0) {
223 __net_timestamp(skb);
224 sock_enable_timestamp(sk);
227 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
228 goto discard_release;
231 if (sk_filter(sk, skb))
232 goto discard_release;
234 /* Create an SCTP packet structure. */
235 chunk = sctp_chunkify(skb, asoc, sk);
237 goto discard_release;
238 SCTP_INPUT_CB(skb)->chunk = chunk;
240 /* Remember what endpoint is to handle this packet. */
243 /* Remember the SCTP header. */
244 chunk->sctp_hdr = sh;
246 /* Set the source and destination addresses of the incoming chunk. */
247 sctp_init_addrs(chunk, &src, &dest);
249 /* Remember where we came from. */
250 chunk->transport = transport;
252 /* Acquire access to the sock lock. Note: We are safe from other
253 * bottom halves on this lock, but a user may be in the lock too,
254 * so check if it is busy.
256 sctp_bh_lock_sock(sk);
258 if (sock_owned_by_user(sk)) {
259 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG);
260 sctp_add_backlog(sk, skb);
262 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ);
263 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
266 sctp_bh_unlock_sock(sk);
268 /* Release the asoc/ep ref we took in the lookup calls. */
270 sctp_association_put(asoc);
272 sctp_endpoint_put(ep);
277 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS);
282 /* Release the asoc/ep ref we took in the lookup calls. */
284 sctp_association_put(asoc);
286 sctp_endpoint_put(ep);
291 /* Process the backlog queue of the socket. Every skb on
292 * the backlog holds a ref on an association or endpoint.
293 * We hold this ref throughout the state machine to make
294 * sure that the structure we need is still around.
296 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
298 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
299 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
300 struct sctp_ep_common *rcvr = NULL;
305 /* If the rcvr is dead then the association or endpoint
306 * has been deleted and we can safely drop the chunk
307 * and refs that we are holding.
310 sctp_chunk_free(chunk);
314 if (unlikely(rcvr->sk != sk)) {
315 /* In this case, the association moved from one socket to
316 * another. We are currently sitting on the backlog of the
317 * old socket, so we need to move.
318 * However, since we are here in the process context we
319 * need to take make sure that the user doesn't own
320 * the new socket when we process the packet.
321 * If the new socket is user-owned, queue the chunk to the
322 * backlog of the new socket without dropping any refs.
323 * Otherwise, we can safely push the chunk on the inqueue.
327 sctp_bh_lock_sock(sk);
329 if (sock_owned_by_user(sk)) {
330 sk_add_backlog(sk, skb);
333 sctp_inq_push(inqueue, chunk);
335 sctp_bh_unlock_sock(sk);
337 /* If the chunk was backloged again, don't drop refs */
341 sctp_inq_push(inqueue, chunk);
345 /* Release the refs we took in sctp_add_backlog */
346 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
347 sctp_association_put(sctp_assoc(rcvr));
348 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
349 sctp_endpoint_put(sctp_ep(rcvr));
356 static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
358 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
359 struct sctp_ep_common *rcvr = chunk->rcvr;
361 /* Hold the assoc/ep while hanging on the backlog queue.
362 * This way, we know structures we need will not disappear from us
364 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
365 sctp_association_hold(sctp_assoc(rcvr));
366 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
367 sctp_endpoint_hold(sctp_ep(rcvr));
371 sk_add_backlog(sk, skb);
374 /* Handle icmp frag needed error. */
375 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
376 struct sctp_transport *t, __u32 pmtu)
378 if (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu))
381 if (t->param_flags & SPP_PMTUD_ENABLE) {
382 if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
383 printk(KERN_WARNING "%s: Reported pmtu %d too low, "
384 "using default minimum of %d\n",
386 SCTP_DEFAULT_MINSEGMENT);
387 /* Use default minimum segment size and disable
388 * pmtu discovery on this transport.
390 t->pathmtu = SCTP_DEFAULT_MINSEGMENT;
391 t->param_flags = (t->param_flags & ~SPP_HB) |
397 /* Update association pmtu. */
398 sctp_assoc_sync_pmtu(asoc);
401 /* Retransmit with the new pmtu setting.
402 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
403 * Needed will never be sent, but if a message was sent before
404 * PMTU discovery was disabled that was larger than the PMTU, it
405 * would not be fragmented, so it must be re-transmitted fragmented.
407 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
411 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
413 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
414 * or a "Protocol Unreachable" treat this message as an abort
415 * with the T bit set.
417 * This function sends an event to the state machine, which will abort the
421 void sctp_icmp_proto_unreachable(struct sock *sk,
422 struct sctp_association *asoc,
423 struct sctp_transport *t)
425 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__);
427 sctp_do_sm(SCTP_EVENT_T_OTHER,
428 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
429 asoc->state, asoc->ep, asoc, t,
434 /* Common lookup code for icmp/icmpv6 error handler. */
435 struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
436 struct sctphdr *sctphdr,
437 struct sctp_association **app,
438 struct sctp_transport **tpp)
440 union sctp_addr saddr;
441 union sctp_addr daddr;
443 struct sock *sk = NULL;
444 struct sctp_association *asoc;
445 struct sctp_transport *transport = NULL;
447 *app = NULL; *tpp = NULL;
449 af = sctp_get_af_specific(family);
454 /* Initialize local addresses for lookups. */
455 af->from_skb(&saddr, skb, 1);
456 af->from_skb(&daddr, skb, 0);
458 /* Look for an association that matches the incoming ICMP error
461 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
467 if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
468 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
472 sctp_bh_lock_sock(sk);
474 /* If too many ICMPs get dropped on busy
475 * servers this needs to be solved differently.
477 if (sock_owned_by_user(sk))
478 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
486 sctp_association_put(asoc);
490 /* Common cleanup code for icmp/icmpv6 error handler. */
491 void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
493 sctp_bh_unlock_sock(sk);
495 sctp_association_put(asoc);
499 * This routine is called by the ICMP module when it gets some
500 * sort of error condition. If err < 0 then the socket should
501 * be closed and the error returned to the user. If err > 0
502 * it's just the icmp type << 8 | icmp code. After adjustment
503 * header points to the first 8 bytes of the sctp header. We need
504 * to find the appropriate port.
506 * The locking strategy used here is very "optimistic". When
507 * someone else accesses the socket the ICMP is just dropped
508 * and for some paths there is no check at all.
509 * A more general error queue to queue errors for later handling
510 * is probably better.
513 void sctp_v4_err(struct sk_buff *skb, __u32 info)
515 struct iphdr *iph = (struct iphdr *)skb->data;
516 struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2));
517 int type = skb->h.icmph->type;
518 int code = skb->h.icmph->code;
520 struct sctp_association *asoc = NULL;
521 struct sctp_transport *transport;
522 struct inet_sock *inet;
523 char *saveip, *savesctp;
526 if (skb->len < ((iph->ihl << 2) + 8)) {
527 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
531 /* Fix up skb to look at the embedded net header. */
532 saveip = skb->nh.raw;
533 savesctp = skb->h.raw;
535 skb->h.raw = (char *)sh;
536 sk = sctp_err_lookup(AF_INET, skb, sh, &asoc, &transport);
537 /* Put back, the original pointers. */
538 skb->nh.raw = saveip;
539 skb->h.raw = savesctp;
541 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
544 /* Warning: The sock lock is held. Remember to call
549 case ICMP_PARAMETERPROB:
552 case ICMP_DEST_UNREACH:
553 if (code > NR_ICMP_UNREACH)
556 /* PMTU discovery (RFC1191) */
557 if (ICMP_FRAG_NEEDED == code) {
558 sctp_icmp_frag_needed(sk, asoc, transport, info);
562 if (ICMP_PROT_UNREACH == code) {
563 sctp_icmp_proto_unreachable(sk, asoc,
568 err = icmp_err_convert[code].errno;
570 case ICMP_TIME_EXCEEDED:
571 /* Ignore any time exceeded errors due to fragment reassembly
574 if (ICMP_EXC_FRAGTIME == code)
584 if (!sock_owned_by_user(sk) && inet->recverr) {
586 sk->sk_error_report(sk);
587 } else { /* Only an error on timeout */
588 sk->sk_err_soft = err;
592 sctp_err_finish(sk, asoc);
596 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
598 * This function scans all the chunks in the OOTB packet to determine if
599 * the packet should be discarded right away. If a response might be needed
600 * for this packet, or, if further processing is possible, the packet will
601 * be queued to a proper inqueue for the next phase of handling.
604 * Return 0 - If further processing is needed.
605 * Return 1 - If the packet can be discarded right away.
607 int sctp_rcv_ootb(struct sk_buff *skb)
613 ch = (sctp_chunkhdr_t *) skb->data;
615 /* Scan through all the chunks in the packet. */
617 /* Break out if chunk length is less then minimal. */
618 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
621 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
622 if (ch_end > skb->tail)
625 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
626 * receiver MUST silently discard the OOTB packet and take no
629 if (SCTP_CID_ABORT == ch->type)
632 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
633 * chunk, the receiver should silently discard the packet
634 * and take no further action.
636 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
639 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
640 * or a COOKIE ACK the SCTP Packet should be silently
643 if (SCTP_CID_COOKIE_ACK == ch->type)
646 if (SCTP_CID_ERROR == ch->type) {
647 sctp_walk_errors(err, ch) {
648 if (SCTP_ERROR_STALE_COOKIE == err->cause)
653 ch = (sctp_chunkhdr_t *) ch_end;
654 } while (ch_end < skb->tail);
662 /* Insert endpoint into the hash table. */
663 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
665 struct sctp_ep_common **epp;
666 struct sctp_ep_common *epb;
667 struct sctp_hashbucket *head;
671 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
672 head = &sctp_ep_hashtable[epb->hashent];
674 sctp_write_lock(&head->lock);
678 (*epp)->pprev = &epb->next;
681 sctp_write_unlock(&head->lock);
684 /* Add an endpoint to the hash. Local BH-safe. */
685 void sctp_hash_endpoint(struct sctp_endpoint *ep)
687 sctp_local_bh_disable();
688 __sctp_hash_endpoint(ep);
689 sctp_local_bh_enable();
692 /* Remove endpoint from the hash table. */
693 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
695 struct sctp_hashbucket *head;
696 struct sctp_ep_common *epb;
700 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
702 head = &sctp_ep_hashtable[epb->hashent];
704 sctp_write_lock(&head->lock);
708 epb->next->pprev = epb->pprev;
709 *epb->pprev = epb->next;
713 sctp_write_unlock(&head->lock);
716 /* Remove endpoint from the hash. Local BH-safe. */
717 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
719 sctp_local_bh_disable();
720 __sctp_unhash_endpoint(ep);
721 sctp_local_bh_enable();
724 /* Look up an endpoint. */
725 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
727 struct sctp_hashbucket *head;
728 struct sctp_ep_common *epb;
729 struct sctp_endpoint *ep;
732 hash = sctp_ep_hashfn(laddr->v4.sin_port);
733 head = &sctp_ep_hashtable[hash];
734 read_lock(&head->lock);
735 for (epb = head->chain; epb; epb = epb->next) {
737 if (sctp_endpoint_is_match(ep, laddr))
741 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
745 sctp_endpoint_hold(ep);
746 read_unlock(&head->lock);
750 /* Insert association into the hash table. */
751 static void __sctp_hash_established(struct sctp_association *asoc)
753 struct sctp_ep_common **epp;
754 struct sctp_ep_common *epb;
755 struct sctp_hashbucket *head;
759 /* Calculate which chain this entry will belong to. */
760 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
762 head = &sctp_assoc_hashtable[epb->hashent];
764 sctp_write_lock(&head->lock);
768 (*epp)->pprev = &epb->next;
771 sctp_write_unlock(&head->lock);
774 /* Add an association to the hash. Local BH-safe. */
775 void sctp_hash_established(struct sctp_association *asoc)
777 sctp_local_bh_disable();
778 __sctp_hash_established(asoc);
779 sctp_local_bh_enable();
782 /* Remove association from the hash table. */
783 static void __sctp_unhash_established(struct sctp_association *asoc)
785 struct sctp_hashbucket *head;
786 struct sctp_ep_common *epb;
790 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
793 head = &sctp_assoc_hashtable[epb->hashent];
795 sctp_write_lock(&head->lock);
799 epb->next->pprev = epb->pprev;
800 *epb->pprev = epb->next;
804 sctp_write_unlock(&head->lock);
807 /* Remove association from the hash table. Local BH-safe. */
808 void sctp_unhash_established(struct sctp_association *asoc)
810 sctp_local_bh_disable();
811 __sctp_unhash_established(asoc);
812 sctp_local_bh_enable();
815 /* Look up an association. */
816 static struct sctp_association *__sctp_lookup_association(
817 const union sctp_addr *local,
818 const union sctp_addr *peer,
819 struct sctp_transport **pt)
821 struct sctp_hashbucket *head;
822 struct sctp_ep_common *epb;
823 struct sctp_association *asoc;
824 struct sctp_transport *transport;
827 /* Optimize here for direct hit, only listening connections can
828 * have wildcards anyways.
830 hash = sctp_assoc_hashfn(local->v4.sin_port, peer->v4.sin_port);
831 head = &sctp_assoc_hashtable[hash];
832 read_lock(&head->lock);
833 for (epb = head->chain; epb; epb = epb->next) {
834 asoc = sctp_assoc(epb);
835 transport = sctp_assoc_is_match(asoc, local, peer);
840 read_unlock(&head->lock);
846 sctp_association_hold(asoc);
847 read_unlock(&head->lock);
851 /* Look up an association. BH-safe. */
853 struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
854 const union sctp_addr *paddr,
855 struct sctp_transport **transportp)
857 struct sctp_association *asoc;
859 sctp_local_bh_disable();
860 asoc = __sctp_lookup_association(laddr, paddr, transportp);
861 sctp_local_bh_enable();
866 /* Is there an association matching the given local and peer addresses? */
867 int sctp_has_association(const union sctp_addr *laddr,
868 const union sctp_addr *paddr)
870 struct sctp_association *asoc;
871 struct sctp_transport *transport;
873 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
874 sctp_association_put(asoc);
882 * SCTP Implementors Guide, 2.18 Handling of address
883 * parameters within the INIT or INIT-ACK.
885 * D) When searching for a matching TCB upon reception of an INIT
886 * or INIT-ACK chunk the receiver SHOULD use not only the
887 * source address of the packet (containing the INIT or
888 * INIT-ACK) but the receiver SHOULD also use all valid
889 * address parameters contained within the chunk.
891 * 2.18.3 Solution description
893 * This new text clearly specifies to an implementor the need
894 * to look within the INIT or INIT-ACK. Any implementation that
895 * does not do this, may not be able to establish associations
896 * in certain circumstances.
899 static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
900 const union sctp_addr *laddr, struct sctp_transport **transportp)
902 struct sctp_association *asoc;
903 union sctp_addr addr;
904 union sctp_addr *paddr = &addr;
905 struct sctphdr *sh = (struct sctphdr *) skb->h.raw;
907 union sctp_params params;
908 sctp_init_chunk_t *init;
909 struct sctp_transport *transport;
912 ch = (sctp_chunkhdr_t *) skb->data;
914 /* If this is INIT/INIT-ACK look inside the chunk too. */
917 case SCTP_CID_INIT_ACK:
923 /* The code below will attempt to walk the chunk and extract
924 * parameter information. Before we do that, we need to verify
925 * that the chunk length doesn't cause overflow. Otherwise, we'll
928 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
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, ntohs(sh->source), 0);
959 asoc = __sctp_lookup_association(laddr, paddr, &transport);
967 /* Lookup an association for an inbound skb. */
968 static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
969 const union sctp_addr *paddr,
970 const union sctp_addr *laddr,
971 struct sctp_transport **transportp)
973 struct sctp_association *asoc;
975 asoc = __sctp_lookup_association(laddr, paddr, transportp);
977 /* Further lookup for INIT/INIT-ACK packets.
978 * SCTP Implementors Guide, 2.18 Handling of address
979 * parameters within the INIT or INIT-ACK.
982 asoc = __sctp_rcv_init_lookup(skb, laddr, transportp);