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);
77 /* Calculate the SCTP checksum of an SCTP packet. */
78 static inline int sctp_rcv_checksum(struct sk_buff *skb)
82 struct sk_buff *list = skb_shinfo(skb)->frag_list;
84 sh = (struct sctphdr *) skb->h.raw;
85 cmp = ntohl(sh->checksum);
87 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;
132 if (skb->pkt_type!=PACKET_HOST)
135 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
137 sh = (struct sctphdr *) skb->h.raw;
139 /* Pull up the IP and SCTP headers. */
140 __skb_pull(skb, skb->h.raw - skb->data);
141 if (skb->len < sizeof(struct sctphdr))
143 if (sctp_rcv_checksum(skb) < 0)
146 skb_pull(skb, sizeof(struct sctphdr));
148 /* Make sure we at least have chunk headers worth of data left. */
149 if (skb->len < sizeof(struct sctp_chunkhdr))
152 family = ipver2af(skb->nh.iph->version);
153 af = sctp_get_af_specific(family);
157 /* Initialize local addresses for lookups. */
158 af->from_skb(&src, skb, 1);
159 af->from_skb(&dest, skb, 0);
161 /* If the packet is to or from a non-unicast address,
162 * silently discard the packet.
164 * This is not clearly defined in the RFC except in section
165 * 8.4 - OOTB handling. However, based on the book "Stream Control
166 * Transmission Protocol" 2.1, "It is important to note that the
167 * IP address of an SCTP transport address must be a routable
168 * unicast address. In other words, IP multicast addresses and
169 * IP broadcast addresses cannot be used in an SCTP transport
172 if (!af->addr_valid(&src, NULL) || !af->addr_valid(&dest, NULL))
175 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
178 ep = __sctp_rcv_lookup_endpoint(&dest);
180 /* Retrieve the common input handling substructure. */
181 rcvr = asoc ? &asoc->base : &ep->base;
185 * If a frame arrives on an interface and the receiving socket is
186 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
188 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
192 sctp_association_put(asoc);
195 sctp_endpoint_put(ep);
198 sk = sctp_get_ctl_sock();
199 ep = sctp_sk(sk)->ep;
200 sctp_endpoint_hold(ep);
206 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
207 * An SCTP packet is called an "out of the blue" (OOTB)
208 * packet if it is correctly formed, i.e., passed the
209 * receiver's checksum check, but the receiver is not
210 * able to identify the association to which this
214 if (sctp_rcv_ootb(skb)) {
215 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
216 goto discard_release;
220 /* SCTP seems to always need a timestamp right now (FIXME) */
221 if (skb->tstamp.off_sec == 0) {
222 __net_timestamp(skb);
223 sock_enable_timestamp(sk);
226 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
227 goto discard_release;
230 ret = sk_filter(sk, skb, 1);
232 goto discard_release;
234 /* Create an SCTP packet structure. */
235 chunk = sctp_chunkify(skb, asoc, sk);
238 goto discard_release;
240 SCTP_INPUT_CB(skb)->chunk = chunk;
242 /* Remember what endpoint is to handle this packet. */
245 /* Remember the SCTP header. */
246 chunk->sctp_hdr = sh;
248 /* Set the source and destination addresses of the incoming chunk. */
249 sctp_init_addrs(chunk, &src, &dest);
251 /* Remember where we came from. */
252 chunk->transport = transport;
254 /* Acquire access to the sock lock. Note: We are safe from other
255 * bottom halves on this lock, but a user may be in the lock too,
256 * so check if it is busy.
258 sctp_bh_lock_sock(sk);
260 /* It is possible that the association could have moved to a different
261 * socket if it is peeled off. If so, update the sk.
263 if (sk != rcvr->sk) {
264 sctp_bh_lock_sock(rcvr->sk);
265 sctp_bh_unlock_sock(sk);
269 if (sock_owned_by_user(sk))
270 sk_add_backlog(sk, skb);
272 sctp_backlog_rcv(sk, skb);
274 /* Release the sock and the sock ref we took in the lookup calls.
275 * The asoc/ep ref will be released in sctp_backlog_rcv.
277 sctp_bh_unlock_sock(sk);
287 /* Release any structures we may be holding. */
290 sctp_association_put(asoc);
292 sctp_endpoint_put(ep);
297 /* Handle second half of inbound skb processing. If the sock was busy,
298 * we may have need to delay processing until later when the sock is
299 * released (on the backlog). If not busy, we call this routine
300 * directly from the bottom half.
302 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
304 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
305 struct sctp_inq *inqueue = NULL;
306 struct sctp_ep_common *rcvr = NULL;
310 BUG_TRAP(rcvr->sk == sk);
313 sctp_chunk_free(chunk);
315 inqueue = &chunk->rcvr->inqueue;
316 sctp_inq_push(inqueue, chunk);
319 /* Release the asoc/ep ref we took in the lookup calls in sctp_rcv. */
320 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
321 sctp_association_put(sctp_assoc(rcvr));
323 sctp_endpoint_put(sctp_ep(rcvr));
328 void sctp_backlog_migrate(struct sctp_association *assoc,
329 struct sock *oldsk, struct sock *newsk)
332 struct sctp_chunk *chunk;
334 skb = oldsk->sk_backlog.head;
335 oldsk->sk_backlog.head = oldsk->sk_backlog.tail = NULL;
336 while (skb != NULL) {
337 struct sk_buff *next = skb->next;
339 chunk = SCTP_INPUT_CB(skb)->chunk;
341 if (&assoc->base == chunk->rcvr)
342 sk_add_backlog(newsk, skb);
344 sk_add_backlog(oldsk, skb);
349 /* Handle icmp frag needed error. */
350 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
351 struct sctp_transport *t, __u32 pmtu)
353 if (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu))
356 if (t->param_flags & SPP_PMTUD_ENABLE) {
357 if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
358 printk(KERN_WARNING "%s: Reported pmtu %d too low, "
359 "using default minimum of %d\n",
361 SCTP_DEFAULT_MINSEGMENT);
362 /* Use default minimum segment size and disable
363 * pmtu discovery on this transport.
365 t->pathmtu = SCTP_DEFAULT_MINSEGMENT;
366 t->param_flags = (t->param_flags & ~SPP_HB) |
372 /* Update association pmtu. */
373 sctp_assoc_sync_pmtu(asoc);
376 /* Retransmit with the new pmtu setting.
377 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
378 * Needed will never be sent, but if a message was sent before
379 * PMTU discovery was disabled that was larger than the PMTU, it
380 * would not be fragmented, so it must be re-transmitted fragmented.
382 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
386 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
388 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
389 * or a "Protocol Unreachable" treat this message as an abort
390 * with the T bit set.
392 * This function sends an event to the state machine, which will abort the
396 void sctp_icmp_proto_unreachable(struct sock *sk,
397 struct sctp_association *asoc,
398 struct sctp_transport *t)
400 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__);
402 sctp_do_sm(SCTP_EVENT_T_OTHER,
403 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
404 asoc->state, asoc->ep, asoc, t,
409 /* Common lookup code for icmp/icmpv6 error handler. */
410 struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
411 struct sctphdr *sctphdr,
412 struct sctp_association **app,
413 struct sctp_transport **tpp)
415 union sctp_addr saddr;
416 union sctp_addr daddr;
418 struct sock *sk = NULL;
419 struct sctp_association *asoc = NULL;
420 struct sctp_transport *transport = NULL;
422 *app = NULL; *tpp = NULL;
424 af = sctp_get_af_specific(family);
429 /* Initialize local addresses for lookups. */
430 af->from_skb(&saddr, skb, 1);
431 af->from_skb(&daddr, skb, 0);
433 /* Look for an association that matches the incoming ICMP error
436 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
442 if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
443 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
447 sctp_bh_lock_sock(sk);
449 /* If too many ICMPs get dropped on busy
450 * servers this needs to be solved differently.
452 if (sock_owned_by_user(sk))
453 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
462 sctp_association_put(asoc);
466 /* Common cleanup code for icmp/icmpv6 error handler. */
467 void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
469 sctp_bh_unlock_sock(sk);
472 sctp_association_put(asoc);
476 * This routine is called by the ICMP module when it gets some
477 * sort of error condition. If err < 0 then the socket should
478 * be closed and the error returned to the user. If err > 0
479 * it's just the icmp type << 8 | icmp code. After adjustment
480 * header points to the first 8 bytes of the sctp header. We need
481 * to find the appropriate port.
483 * The locking strategy used here is very "optimistic". When
484 * someone else accesses the socket the ICMP is just dropped
485 * and for some paths there is no check at all.
486 * A more general error queue to queue errors for later handling
487 * is probably better.
490 void sctp_v4_err(struct sk_buff *skb, __u32 info)
492 struct iphdr *iph = (struct iphdr *)skb->data;
493 struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2));
494 int type = skb->h.icmph->type;
495 int code = skb->h.icmph->code;
497 struct sctp_association *asoc;
498 struct sctp_transport *transport;
499 struct inet_sock *inet;
500 char *saveip, *savesctp;
503 if (skb->len < ((iph->ihl << 2) + 8)) {
504 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
508 /* Fix up skb to look at the embedded net header. */
509 saveip = skb->nh.raw;
510 savesctp = skb->h.raw;
512 skb->h.raw = (char *)sh;
513 sk = sctp_err_lookup(AF_INET, skb, sh, &asoc, &transport);
514 /* Put back, the original pointers. */
515 skb->nh.raw = saveip;
516 skb->h.raw = savesctp;
518 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
521 /* Warning: The sock lock is held. Remember to call
526 case ICMP_PARAMETERPROB:
529 case ICMP_DEST_UNREACH:
530 if (code > NR_ICMP_UNREACH)
533 /* PMTU discovery (RFC1191) */
534 if (ICMP_FRAG_NEEDED == code) {
535 sctp_icmp_frag_needed(sk, asoc, transport, info);
539 if (ICMP_PROT_UNREACH == code) {
540 sctp_icmp_proto_unreachable(sk, asoc,
545 err = icmp_err_convert[code].errno;
547 case ICMP_TIME_EXCEEDED:
548 /* Ignore any time exceeded errors due to fragment reassembly
551 if (ICMP_EXC_FRAGTIME == code)
561 if (!sock_owned_by_user(sk) && inet->recverr) {
563 sk->sk_error_report(sk);
564 } else { /* Only an error on timeout */
565 sk->sk_err_soft = err;
569 sctp_err_finish(sk, asoc);
573 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
575 * This function scans all the chunks in the OOTB packet to determine if
576 * the packet should be discarded right away. If a response might be needed
577 * for this packet, or, if further processing is possible, the packet will
578 * be queued to a proper inqueue for the next phase of handling.
581 * Return 0 - If further processing is needed.
582 * Return 1 - If the packet can be discarded right away.
584 int sctp_rcv_ootb(struct sk_buff *skb)
590 ch = (sctp_chunkhdr_t *) skb->data;
591 ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length));
593 /* Scan through all the chunks in the packet. */
594 while (ch_end > (__u8 *)ch && ch_end < skb->tail) {
596 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
597 * receiver MUST silently discard the OOTB packet and take no
600 if (SCTP_CID_ABORT == ch->type)
603 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
604 * chunk, the receiver should silently discard the packet
605 * and take no further action.
607 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
610 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
611 * or a COOKIE ACK the SCTP Packet should be silently
614 if (SCTP_CID_COOKIE_ACK == ch->type)
617 if (SCTP_CID_ERROR == ch->type) {
618 sctp_walk_errors(err, ch) {
619 if (SCTP_ERROR_STALE_COOKIE == err->cause)
624 ch = (sctp_chunkhdr_t *) ch_end;
625 ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length));
634 /* Insert endpoint into the hash table. */
635 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
637 struct sctp_ep_common **epp;
638 struct sctp_ep_common *epb;
639 struct sctp_hashbucket *head;
643 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
644 head = &sctp_ep_hashtable[epb->hashent];
646 sctp_write_lock(&head->lock);
650 (*epp)->pprev = &epb->next;
653 sctp_write_unlock(&head->lock);
656 /* Add an endpoint to the hash. Local BH-safe. */
657 void sctp_hash_endpoint(struct sctp_endpoint *ep)
659 sctp_local_bh_disable();
660 __sctp_hash_endpoint(ep);
661 sctp_local_bh_enable();
664 /* Remove endpoint from the hash table. */
665 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
667 struct sctp_hashbucket *head;
668 struct sctp_ep_common *epb;
672 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
674 head = &sctp_ep_hashtable[epb->hashent];
676 sctp_write_lock(&head->lock);
680 epb->next->pprev = epb->pprev;
681 *epb->pprev = epb->next;
685 sctp_write_unlock(&head->lock);
688 /* Remove endpoint from the hash. Local BH-safe. */
689 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
691 sctp_local_bh_disable();
692 __sctp_unhash_endpoint(ep);
693 sctp_local_bh_enable();
696 /* Look up an endpoint. */
697 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
699 struct sctp_hashbucket *head;
700 struct sctp_ep_common *epb;
701 struct sctp_endpoint *ep;
704 hash = sctp_ep_hashfn(laddr->v4.sin_port);
705 head = &sctp_ep_hashtable[hash];
706 read_lock(&head->lock);
707 for (epb = head->chain; epb; epb = epb->next) {
709 if (sctp_endpoint_is_match(ep, laddr))
713 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
717 sctp_endpoint_hold(ep);
719 read_unlock(&head->lock);
723 /* Insert association into the hash table. */
724 static void __sctp_hash_established(struct sctp_association *asoc)
726 struct sctp_ep_common **epp;
727 struct sctp_ep_common *epb;
728 struct sctp_hashbucket *head;
732 /* Calculate which chain this entry will belong to. */
733 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
735 head = &sctp_assoc_hashtable[epb->hashent];
737 sctp_write_lock(&head->lock);
741 (*epp)->pprev = &epb->next;
744 sctp_write_unlock(&head->lock);
747 /* Add an association to the hash. Local BH-safe. */
748 void sctp_hash_established(struct sctp_association *asoc)
750 sctp_local_bh_disable();
751 __sctp_hash_established(asoc);
752 sctp_local_bh_enable();
755 /* Remove association from the hash table. */
756 static void __sctp_unhash_established(struct sctp_association *asoc)
758 struct sctp_hashbucket *head;
759 struct sctp_ep_common *epb;
763 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
766 head = &sctp_assoc_hashtable[epb->hashent];
768 sctp_write_lock(&head->lock);
772 epb->next->pprev = epb->pprev;
773 *epb->pprev = epb->next;
777 sctp_write_unlock(&head->lock);
780 /* Remove association from the hash table. Local BH-safe. */
781 void sctp_unhash_established(struct sctp_association *asoc)
783 sctp_local_bh_disable();
784 __sctp_unhash_established(asoc);
785 sctp_local_bh_enable();
788 /* Look up an association. */
789 static struct sctp_association *__sctp_lookup_association(
790 const union sctp_addr *local,
791 const union sctp_addr *peer,
792 struct sctp_transport **pt)
794 struct sctp_hashbucket *head;
795 struct sctp_ep_common *epb;
796 struct sctp_association *asoc;
797 struct sctp_transport *transport;
800 /* Optimize here for direct hit, only listening connections can
801 * have wildcards anyways.
803 hash = sctp_assoc_hashfn(local->v4.sin_port, peer->v4.sin_port);
804 head = &sctp_assoc_hashtable[hash];
805 read_lock(&head->lock);
806 for (epb = head->chain; epb; epb = epb->next) {
807 asoc = sctp_assoc(epb);
808 transport = sctp_assoc_is_match(asoc, local, peer);
813 read_unlock(&head->lock);
819 sctp_association_hold(asoc);
821 read_unlock(&head->lock);
825 /* Look up an association. BH-safe. */
827 struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
828 const union sctp_addr *paddr,
829 struct sctp_transport **transportp)
831 struct sctp_association *asoc;
833 sctp_local_bh_disable();
834 asoc = __sctp_lookup_association(laddr, paddr, transportp);
835 sctp_local_bh_enable();
840 /* Is there an association matching the given local and peer addresses? */
841 int sctp_has_association(const union sctp_addr *laddr,
842 const union sctp_addr *paddr)
844 struct sctp_association *asoc;
845 struct sctp_transport *transport;
847 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
848 sock_put(asoc->base.sk);
849 sctp_association_put(asoc);
857 * SCTP Implementors Guide, 2.18 Handling of address
858 * parameters within the INIT or INIT-ACK.
860 * D) When searching for a matching TCB upon reception of an INIT
861 * or INIT-ACK chunk the receiver SHOULD use not only the
862 * source address of the packet (containing the INIT or
863 * INIT-ACK) but the receiver SHOULD also use all valid
864 * address parameters contained within the chunk.
866 * 2.18.3 Solution description
868 * This new text clearly specifies to an implementor the need
869 * to look within the INIT or INIT-ACK. Any implementation that
870 * does not do this, may not be able to establish associations
871 * in certain circumstances.
874 static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
875 const union sctp_addr *laddr, struct sctp_transport **transportp)
877 struct sctp_association *asoc;
878 union sctp_addr addr;
879 union sctp_addr *paddr = &addr;
880 struct sctphdr *sh = (struct sctphdr *) skb->h.raw;
882 union sctp_params params;
883 sctp_init_chunk_t *init;
884 struct sctp_transport *transport;
887 ch = (sctp_chunkhdr_t *) skb->data;
889 /* If this is INIT/INIT-ACK look inside the chunk too. */
892 case SCTP_CID_INIT_ACK:
898 /* The code below will attempt to walk the chunk and extract
899 * parameter information. Before we do that, we need to verify
900 * that the chunk length doesn't cause overflow. Otherwise, we'll
903 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
907 * This code will NOT touch anything inside the chunk--it is
908 * strictly READ-ONLY.
910 * RFC 2960 3 SCTP packet Format
912 * Multiple chunks can be bundled into one SCTP packet up to
913 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
914 * COMPLETE chunks. These chunks MUST NOT be bundled with any
915 * other chunk in a packet. See Section 6.10 for more details
919 /* Find the start of the TLVs and the end of the chunk. This is
920 * the region we search for address parameters.
922 init = (sctp_init_chunk_t *)skb->data;
924 /* Walk the parameters looking for embedded addresses. */
925 sctp_walk_params(params, init, init_hdr.params) {
927 /* Note: Ignoring hostname addresses. */
928 af = sctp_get_af_specific(param_type2af(params.p->type));
932 af->from_addr_param(paddr, params.addr, ntohs(sh->source), 0);
934 asoc = __sctp_lookup_association(laddr, paddr, &transport);
942 /* Lookup an association for an inbound skb. */
943 static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
944 const union sctp_addr *paddr,
945 const union sctp_addr *laddr,
946 struct sctp_transport **transportp)
948 struct sctp_association *asoc;
950 asoc = __sctp_lookup_association(laddr, paddr, transportp);
952 /* Further lookup for INIT/INIT-ACK packets.
953 * SCTP Implementors Guide, 2.18 Handling of address
954 * parameters within the INIT or INIT-ACK.
957 asoc = __sctp_rcv_init_lookup(skb, laddr, transportp);