ARM: multi_v7_defconfig: add SDHCI for i.MX
[linux-2.6.git] / net / sctp / input.c
blob5f2068679f8339b8a85b85cf2dc7b185a663dd9c
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)
17 * any later version.
19 * This SCTP implementation is distributed in the hope that it
20 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
21 * ************************
22 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23 * See the GNU General Public License for more details.
25 * You should have received a copy of the GNU General Public License
26 * along with GNU CC; see the file COPYING. If not, write to
27 * the Free Software Foundation, 59 Temple Place - Suite 330,
28 * Boston, MA 02111-1307, USA.
30 * Please send any bug reports or fixes you make to the
31 * email address(es):
32 * lksctp developers <linux-sctp@vger.kernel.org>
34 * Written or modified by:
35 * La Monte H.P. Yarroll <piggy@acm.org>
36 * Karl Knutson <karl@athena.chicago.il.us>
37 * Xingang Guo <xingang.guo@intel.com>
38 * Jon Grimm <jgrimm@us.ibm.com>
39 * Hui Huang <hui.huang@nokia.com>
40 * Daisy Chang <daisyc@us.ibm.com>
41 * Sridhar Samudrala <sri@us.ibm.com>
42 * Ardelle Fan <ardelle.fan@intel.com>
45 #include <linux/types.h>
46 #include <linux/list.h> /* For struct list_head */
47 #include <linux/socket.h>
48 #include <linux/ip.h>
49 #include <linux/time.h> /* For struct timeval */
50 #include <linux/slab.h>
51 #include <net/ip.h>
52 #include <net/icmp.h>
53 #include <net/snmp.h>
54 #include <net/sock.h>
55 #include <net/xfrm.h>
56 #include <net/sctp/sctp.h>
57 #include <net/sctp/sm.h>
58 #include <net/sctp/checksum.h>
59 #include <net/net_namespace.h>
61 /* Forward declarations for internal helpers. */
62 static int sctp_rcv_ootb(struct sk_buff *);
63 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
64 struct sk_buff *skb,
65 const union sctp_addr *paddr,
66 const union sctp_addr *laddr,
67 struct sctp_transport **transportp);
68 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
69 const union sctp_addr *laddr);
70 static struct sctp_association *__sctp_lookup_association(
71 struct net *net,
72 const union sctp_addr *local,
73 const union sctp_addr *peer,
74 struct sctp_transport **pt);
76 static int 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 net *net, struct sk_buff *skb)
82 struct sctphdr *sh = sctp_hdr(skb);
83 __le32 cmp = sh->checksum;
84 __le32 val = sctp_compute_cksum(skb, 0);
86 if (val != cmp) {
87 /* CRC failure, dump it. */
88 SCTP_INC_STATS_BH(net, SCTP_MIB_CHECKSUMERRORS);
89 return -1;
91 return 0;
94 struct sctp_input_cb {
95 union {
96 struct inet_skb_parm h4;
97 #if IS_ENABLED(CONFIG_IPV6)
98 struct inet6_skb_parm h6;
99 #endif
100 } header;
101 struct sctp_chunk *chunk;
103 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
106 * This is the routine which IP calls when receiving an SCTP packet.
108 int sctp_rcv(struct sk_buff *skb)
110 struct sock *sk;
111 struct sctp_association *asoc;
112 struct sctp_endpoint *ep = NULL;
113 struct sctp_ep_common *rcvr;
114 struct sctp_transport *transport = NULL;
115 struct sctp_chunk *chunk;
116 struct sctphdr *sh;
117 union sctp_addr src;
118 union sctp_addr dest;
119 int family;
120 struct sctp_af *af;
121 struct net *net = dev_net(skb->dev);
123 if (skb->pkt_type!=PACKET_HOST)
124 goto discard_it;
126 SCTP_INC_STATS_BH(net, SCTP_MIB_INSCTPPACKS);
128 if (skb_linearize(skb))
129 goto discard_it;
131 sh = sctp_hdr(skb);
133 /* Pull up the IP and SCTP headers. */
134 __skb_pull(skb, skb_transport_offset(skb));
135 if (skb->len < sizeof(struct sctphdr))
136 goto discard_it;
137 if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) &&
138 sctp_rcv_checksum(net, skb) < 0)
139 goto discard_it;
141 skb_pull(skb, sizeof(struct sctphdr));
143 /* Make sure we at least have chunk headers worth of data left. */
144 if (skb->len < sizeof(struct sctp_chunkhdr))
145 goto discard_it;
147 family = ipver2af(ip_hdr(skb)->version);
148 af = sctp_get_af_specific(family);
149 if (unlikely(!af))
150 goto discard_it;
152 /* Initialize local addresses for lookups. */
153 af->from_skb(&src, skb, 1);
154 af->from_skb(&dest, skb, 0);
156 /* If the packet is to or from a non-unicast address,
157 * silently discard the packet.
159 * This is not clearly defined in the RFC except in section
160 * 8.4 - OOTB handling. However, based on the book "Stream Control
161 * Transmission Protocol" 2.1, "It is important to note that the
162 * IP address of an SCTP transport address must be a routable
163 * unicast address. In other words, IP multicast addresses and
164 * IP broadcast addresses cannot be used in an SCTP transport
165 * address."
167 if (!af->addr_valid(&src, NULL, skb) ||
168 !af->addr_valid(&dest, NULL, skb))
169 goto discard_it;
171 asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
173 if (!asoc)
174 ep = __sctp_rcv_lookup_endpoint(net, &dest);
176 /* Retrieve the common input handling substructure. */
177 rcvr = asoc ? &asoc->base : &ep->base;
178 sk = rcvr->sk;
181 * If a frame arrives on an interface and the receiving socket is
182 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
184 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
186 if (asoc) {
187 sctp_association_put(asoc);
188 asoc = NULL;
189 } else {
190 sctp_endpoint_put(ep);
191 ep = NULL;
193 sk = net->sctp.ctl_sock;
194 ep = sctp_sk(sk)->ep;
195 sctp_endpoint_hold(ep);
196 rcvr = &ep->base;
200 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
201 * An SCTP packet is called an "out of the blue" (OOTB)
202 * packet if it is correctly formed, i.e., passed the
203 * receiver's checksum check, but the receiver is not
204 * able to identify the association to which this
205 * packet belongs.
207 if (!asoc) {
208 if (sctp_rcv_ootb(skb)) {
209 SCTP_INC_STATS_BH(net, SCTP_MIB_OUTOFBLUES);
210 goto discard_release;
214 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
215 goto discard_release;
216 nf_reset(skb);
218 if (sk_filter(sk, skb))
219 goto discard_release;
221 /* Create an SCTP packet structure. */
222 chunk = sctp_chunkify(skb, asoc, sk);
223 if (!chunk)
224 goto discard_release;
225 SCTP_INPUT_CB(skb)->chunk = chunk;
227 /* Remember what endpoint is to handle this packet. */
228 chunk->rcvr = rcvr;
230 /* Remember the SCTP header. */
231 chunk->sctp_hdr = sh;
233 /* Set the source and destination addresses of the incoming chunk. */
234 sctp_init_addrs(chunk, &src, &dest);
236 /* Remember where we came from. */
237 chunk->transport = transport;
239 /* Acquire access to the sock lock. Note: We are safe from other
240 * bottom halves on this lock, but a user may be in the lock too,
241 * so check if it is busy.
243 sctp_bh_lock_sock(sk);
245 if (sk != rcvr->sk) {
246 /* Our cached sk is different from the rcvr->sk. This is
247 * because migrate()/accept() may have moved the association
248 * to a new socket and released all the sockets. So now we
249 * are holding a lock on the old socket while the user may
250 * be doing something with the new socket. Switch our veiw
251 * of the current sk.
253 sctp_bh_unlock_sock(sk);
254 sk = rcvr->sk;
255 sctp_bh_lock_sock(sk);
258 if (sock_owned_by_user(sk)) {
259 if (sctp_add_backlog(sk, skb)) {
260 sctp_bh_unlock_sock(sk);
261 sctp_chunk_free(chunk);
262 skb = NULL; /* sctp_chunk_free already freed the skb */
263 goto discard_release;
265 SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_BACKLOG);
266 } else {
267 SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ);
268 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
271 sctp_bh_unlock_sock(sk);
273 /* Release the asoc/ep ref we took in the lookup calls. */
274 if (asoc)
275 sctp_association_put(asoc);
276 else
277 sctp_endpoint_put(ep);
279 return 0;
281 discard_it:
282 SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_DISCARDS);
283 kfree_skb(skb);
284 return 0;
286 discard_release:
287 /* Release the asoc/ep ref we took in the lookup calls. */
288 if (asoc)
289 sctp_association_put(asoc);
290 else
291 sctp_endpoint_put(ep);
293 goto discard_it;
296 /* Process the backlog queue of the socket. Every skb on
297 * the backlog holds a ref on an association or endpoint.
298 * We hold this ref throughout the state machine to make
299 * sure that the structure we need is still around.
301 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
303 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
304 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
305 struct sctp_ep_common *rcvr = NULL;
306 int backloged = 0;
308 rcvr = chunk->rcvr;
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.
314 if (rcvr->dead) {
315 sctp_chunk_free(chunk);
316 goto done;
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.
331 sk = rcvr->sk;
332 sctp_bh_lock_sock(sk);
334 if (sock_owned_by_user(sk)) {
335 if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
336 sctp_chunk_free(chunk);
337 else
338 backloged = 1;
339 } else
340 sctp_inq_push(inqueue, chunk);
342 sctp_bh_unlock_sock(sk);
344 /* If the chunk was backloged again, don't drop refs */
345 if (backloged)
346 return 0;
347 } else {
348 sctp_inq_push(inqueue, chunk);
351 done:
352 /* Release the refs we took in sctp_add_backlog */
353 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
354 sctp_association_put(sctp_assoc(rcvr));
355 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
356 sctp_endpoint_put(sctp_ep(rcvr));
357 else
358 BUG();
360 return 0;
363 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
365 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
366 struct sctp_ep_common *rcvr = chunk->rcvr;
367 int ret;
369 ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
370 if (!ret) {
371 /* Hold the assoc/ep while hanging on the backlog queue.
372 * This way, we know structures we need will not disappear
373 * from us
375 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
376 sctp_association_hold(sctp_assoc(rcvr));
377 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
378 sctp_endpoint_hold(sctp_ep(rcvr));
379 else
380 BUG();
382 return ret;
386 /* Handle icmp frag needed error. */
387 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
388 struct sctp_transport *t, __u32 pmtu)
390 if (!t || (t->pathmtu <= pmtu))
391 return;
393 if (sock_owned_by_user(sk)) {
394 asoc->pmtu_pending = 1;
395 t->pmtu_pending = 1;
396 return;
399 if (t->param_flags & SPP_PMTUD_ENABLE) {
400 /* Update transports view of the MTU */
401 sctp_transport_update_pmtu(sk, t, pmtu);
403 /* Update association pmtu. */
404 sctp_assoc_sync_pmtu(sk, asoc);
407 /* Retransmit with the new pmtu setting.
408 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
409 * Needed will never be sent, but if a message was sent before
410 * PMTU discovery was disabled that was larger than the PMTU, it
411 * would not be fragmented, so it must be re-transmitted fragmented.
413 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
416 void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
417 struct sk_buff *skb)
419 struct dst_entry *dst;
421 if (!t)
422 return;
423 dst = sctp_transport_dst_check(t);
424 if (dst)
425 dst->ops->redirect(dst, sk, skb);
429 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
431 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
432 * or a "Protocol Unreachable" treat this message as an abort
433 * with the T bit set.
435 * This function sends an event to the state machine, which will abort the
436 * association.
439 void sctp_icmp_proto_unreachable(struct sock *sk,
440 struct sctp_association *asoc,
441 struct sctp_transport *t)
443 if (sock_owned_by_user(sk)) {
444 if (timer_pending(&t->proto_unreach_timer))
445 return;
446 else {
447 if (!mod_timer(&t->proto_unreach_timer,
448 jiffies + (HZ/20)))
449 sctp_association_hold(asoc);
451 } else {
452 struct net *net = sock_net(sk);
454 pr_debug("%s: unrecognized next header type "
455 "encountered!\n", __func__);
457 if (del_timer(&t->proto_unreach_timer))
458 sctp_association_put(asoc);
460 sctp_do_sm(net, SCTP_EVENT_T_OTHER,
461 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
462 asoc->state, asoc->ep, asoc, t,
463 GFP_ATOMIC);
467 /* Common lookup code for icmp/icmpv6 error handler. */
468 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
469 struct sctphdr *sctphdr,
470 struct sctp_association **app,
471 struct sctp_transport **tpp)
473 union sctp_addr saddr;
474 union sctp_addr daddr;
475 struct sctp_af *af;
476 struct sock *sk = NULL;
477 struct sctp_association *asoc;
478 struct sctp_transport *transport = NULL;
479 struct sctp_init_chunk *chunkhdr;
480 __u32 vtag = ntohl(sctphdr->vtag);
481 int len = skb->len - ((void *)sctphdr - (void *)skb->data);
483 *app = NULL; *tpp = NULL;
485 af = sctp_get_af_specific(family);
486 if (unlikely(!af)) {
487 return NULL;
490 /* Initialize local addresses for lookups. */
491 af->from_skb(&saddr, skb, 1);
492 af->from_skb(&daddr, skb, 0);
494 /* Look for an association that matches the incoming ICMP error
495 * packet.
497 asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport);
498 if (!asoc)
499 return NULL;
501 sk = asoc->base.sk;
503 /* RFC 4960, Appendix C. ICMP Handling
505 * ICMP6) An implementation MUST validate that the Verification Tag
506 * contained in the ICMP message matches the Verification Tag of
507 * the peer. If the Verification Tag is not 0 and does NOT
508 * match, discard the ICMP message. If it is 0 and the ICMP
509 * message contains enough bytes to verify that the chunk type is
510 * an INIT chunk and that the Initiate Tag matches the tag of the
511 * peer, continue with ICMP7. If the ICMP message is too short
512 * or the chunk type or the Initiate Tag does not match, silently
513 * discard the packet.
515 if (vtag == 0) {
516 chunkhdr = (void *)sctphdr + sizeof(struct sctphdr);
517 if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
518 + sizeof(__be32) ||
519 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
520 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
521 goto out;
523 } else if (vtag != asoc->c.peer_vtag) {
524 goto out;
527 sctp_bh_lock_sock(sk);
529 /* If too many ICMPs get dropped on busy
530 * servers this needs to be solved differently.
532 if (sock_owned_by_user(sk))
533 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
535 *app = asoc;
536 *tpp = transport;
537 return sk;
539 out:
540 if (asoc)
541 sctp_association_put(asoc);
542 return NULL;
545 /* Common cleanup code for icmp/icmpv6 error handler. */
546 void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
548 sctp_bh_unlock_sock(sk);
549 if (asoc)
550 sctp_association_put(asoc);
554 * This routine is called by the ICMP module when it gets some
555 * sort of error condition. If err < 0 then the socket should
556 * be closed and the error returned to the user. If err > 0
557 * it's just the icmp type << 8 | icmp code. After adjustment
558 * header points to the first 8 bytes of the sctp header. We need
559 * to find the appropriate port.
561 * The locking strategy used here is very "optimistic". When
562 * someone else accesses the socket the ICMP is just dropped
563 * and for some paths there is no check at all.
564 * A more general error queue to queue errors for later handling
565 * is probably better.
568 void sctp_v4_err(struct sk_buff *skb, __u32 info)
570 const struct iphdr *iph = (const struct iphdr *)skb->data;
571 const int ihlen = iph->ihl * 4;
572 const int type = icmp_hdr(skb)->type;
573 const int code = icmp_hdr(skb)->code;
574 struct sock *sk;
575 struct sctp_association *asoc = NULL;
576 struct sctp_transport *transport;
577 struct inet_sock *inet;
578 __u16 saveip, savesctp;
579 int err;
580 struct net *net = dev_net(skb->dev);
582 if (skb->len < ihlen + 8) {
583 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
584 return;
587 /* Fix up skb to look at the embedded net header. */
588 saveip = skb->network_header;
589 savesctp = skb->transport_header;
590 skb_reset_network_header(skb);
591 skb_set_transport_header(skb, ihlen);
592 sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
593 /* Put back, the original values. */
594 skb->network_header = saveip;
595 skb->transport_header = savesctp;
596 if (!sk) {
597 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
598 return;
600 /* Warning: The sock lock is held. Remember to call
601 * sctp_err_finish!
604 switch (type) {
605 case ICMP_PARAMETERPROB:
606 err = EPROTO;
607 break;
608 case ICMP_DEST_UNREACH:
609 if (code > NR_ICMP_UNREACH)
610 goto out_unlock;
612 /* PMTU discovery (RFC1191) */
613 if (ICMP_FRAG_NEEDED == code) {
614 sctp_icmp_frag_needed(sk, asoc, transport, info);
615 goto out_unlock;
617 else {
618 if (ICMP_PROT_UNREACH == code) {
619 sctp_icmp_proto_unreachable(sk, asoc,
620 transport);
621 goto out_unlock;
624 err = icmp_err_convert[code].errno;
625 break;
626 case ICMP_TIME_EXCEEDED:
627 /* Ignore any time exceeded errors due to fragment reassembly
628 * timeouts.
630 if (ICMP_EXC_FRAGTIME == code)
631 goto out_unlock;
633 err = EHOSTUNREACH;
634 break;
635 case ICMP_REDIRECT:
636 sctp_icmp_redirect(sk, transport, skb);
637 err = 0;
638 break;
639 default:
640 goto out_unlock;
643 inet = inet_sk(sk);
644 if (!sock_owned_by_user(sk) && inet->recverr) {
645 sk->sk_err = err;
646 sk->sk_error_report(sk);
647 } else { /* Only an error on timeout */
648 sk->sk_err_soft = err;
651 out_unlock:
652 sctp_err_finish(sk, asoc);
656 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
658 * This function scans all the chunks in the OOTB packet to determine if
659 * the packet should be discarded right away. If a response might be needed
660 * for this packet, or, if further processing is possible, the packet will
661 * be queued to a proper inqueue for the next phase of handling.
663 * Output:
664 * Return 0 - If further processing is needed.
665 * Return 1 - If the packet can be discarded right away.
667 static int sctp_rcv_ootb(struct sk_buff *skb)
669 sctp_chunkhdr_t *ch;
670 __u8 *ch_end;
672 ch = (sctp_chunkhdr_t *) skb->data;
674 /* Scan through all the chunks in the packet. */
675 do {
676 /* Break out if chunk length is less then minimal. */
677 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
678 break;
680 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
681 if (ch_end > skb_tail_pointer(skb))
682 break;
684 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
685 * receiver MUST silently discard the OOTB packet and take no
686 * further action.
688 if (SCTP_CID_ABORT == ch->type)
689 goto discard;
691 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
692 * chunk, the receiver should silently discard the packet
693 * and take no further action.
695 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
696 goto discard;
698 /* RFC 4460, 2.11.2
699 * This will discard packets with INIT chunk bundled as
700 * subsequent chunks in the packet. When INIT is first,
701 * the normal INIT processing will discard the chunk.
703 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
704 goto discard;
706 ch = (sctp_chunkhdr_t *) ch_end;
707 } while (ch_end < skb_tail_pointer(skb));
709 return 0;
711 discard:
712 return 1;
715 /* Insert endpoint into the hash table. */
716 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
718 struct net *net = sock_net(ep->base.sk);
719 struct sctp_ep_common *epb;
720 struct sctp_hashbucket *head;
722 epb = &ep->base;
724 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
725 head = &sctp_ep_hashtable[epb->hashent];
727 sctp_write_lock(&head->lock);
728 hlist_add_head(&epb->node, &head->chain);
729 sctp_write_unlock(&head->lock);
732 /* Add an endpoint to the hash. Local BH-safe. */
733 void sctp_hash_endpoint(struct sctp_endpoint *ep)
735 sctp_local_bh_disable();
736 __sctp_hash_endpoint(ep);
737 sctp_local_bh_enable();
740 /* Remove endpoint from the hash table. */
741 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
743 struct net *net = sock_net(ep->base.sk);
744 struct sctp_hashbucket *head;
745 struct sctp_ep_common *epb;
747 epb = &ep->base;
749 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
751 head = &sctp_ep_hashtable[epb->hashent];
753 sctp_write_lock(&head->lock);
754 hlist_del_init(&epb->node);
755 sctp_write_unlock(&head->lock);
758 /* Remove endpoint from the hash. Local BH-safe. */
759 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
761 sctp_local_bh_disable();
762 __sctp_unhash_endpoint(ep);
763 sctp_local_bh_enable();
766 /* Look up an endpoint. */
767 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
768 const union sctp_addr *laddr)
770 struct sctp_hashbucket *head;
771 struct sctp_ep_common *epb;
772 struct sctp_endpoint *ep;
773 int hash;
775 hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
776 head = &sctp_ep_hashtable[hash];
777 read_lock(&head->lock);
778 sctp_for_each_hentry(epb, &head->chain) {
779 ep = sctp_ep(epb);
780 if (sctp_endpoint_is_match(ep, net, laddr))
781 goto hit;
784 ep = sctp_sk(net->sctp.ctl_sock)->ep;
786 hit:
787 sctp_endpoint_hold(ep);
788 read_unlock(&head->lock);
789 return ep;
792 /* Insert association into the hash table. */
793 static void __sctp_hash_established(struct sctp_association *asoc)
795 struct net *net = sock_net(asoc->base.sk);
796 struct sctp_ep_common *epb;
797 struct sctp_hashbucket *head;
799 epb = &asoc->base;
801 /* Calculate which chain this entry will belong to. */
802 epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port,
803 asoc->peer.port);
805 head = &sctp_assoc_hashtable[epb->hashent];
807 sctp_write_lock(&head->lock);
808 hlist_add_head(&epb->node, &head->chain);
809 sctp_write_unlock(&head->lock);
812 /* Add an association to the hash. Local BH-safe. */
813 void sctp_hash_established(struct sctp_association *asoc)
815 if (asoc->temp)
816 return;
818 sctp_local_bh_disable();
819 __sctp_hash_established(asoc);
820 sctp_local_bh_enable();
823 /* Remove association from the hash table. */
824 static void __sctp_unhash_established(struct sctp_association *asoc)
826 struct net *net = sock_net(asoc->base.sk);
827 struct sctp_hashbucket *head;
828 struct sctp_ep_common *epb;
830 epb = &asoc->base;
832 epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port,
833 asoc->peer.port);
835 head = &sctp_assoc_hashtable[epb->hashent];
837 sctp_write_lock(&head->lock);
838 hlist_del_init(&epb->node);
839 sctp_write_unlock(&head->lock);
842 /* Remove association from the hash table. Local BH-safe. */
843 void sctp_unhash_established(struct sctp_association *asoc)
845 if (asoc->temp)
846 return;
848 sctp_local_bh_disable();
849 __sctp_unhash_established(asoc);
850 sctp_local_bh_enable();
853 /* Look up an association. */
854 static struct sctp_association *__sctp_lookup_association(
855 struct net *net,
856 const union sctp_addr *local,
857 const union sctp_addr *peer,
858 struct sctp_transport **pt)
860 struct sctp_hashbucket *head;
861 struct sctp_ep_common *epb;
862 struct sctp_association *asoc;
863 struct sctp_transport *transport;
864 int hash;
866 /* Optimize here for direct hit, only listening connections can
867 * have wildcards anyways.
869 hash = sctp_assoc_hashfn(net, ntohs(local->v4.sin_port),
870 ntohs(peer->v4.sin_port));
871 head = &sctp_assoc_hashtable[hash];
872 read_lock(&head->lock);
873 sctp_for_each_hentry(epb, &head->chain) {
874 asoc = sctp_assoc(epb);
875 transport = sctp_assoc_is_match(asoc, net, local, peer);
876 if (transport)
877 goto hit;
880 read_unlock(&head->lock);
882 return NULL;
884 hit:
885 *pt = transport;
886 sctp_association_hold(asoc);
887 read_unlock(&head->lock);
888 return asoc;
891 /* Look up an association. BH-safe. */
892 static
893 struct sctp_association *sctp_lookup_association(struct net *net,
894 const union sctp_addr *laddr,
895 const union sctp_addr *paddr,
896 struct sctp_transport **transportp)
898 struct sctp_association *asoc;
900 sctp_local_bh_disable();
901 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
902 sctp_local_bh_enable();
904 return asoc;
907 /* Is there an association matching the given local and peer addresses? */
908 int sctp_has_association(struct net *net,
909 const union sctp_addr *laddr,
910 const union sctp_addr *paddr)
912 struct sctp_association *asoc;
913 struct sctp_transport *transport;
915 if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) {
916 sctp_association_put(asoc);
917 return 1;
920 return 0;
924 * SCTP Implementors Guide, 2.18 Handling of address
925 * parameters within the INIT or INIT-ACK.
927 * D) When searching for a matching TCB upon reception of an INIT
928 * or INIT-ACK chunk the receiver SHOULD use not only the
929 * source address of the packet (containing the INIT or
930 * INIT-ACK) but the receiver SHOULD also use all valid
931 * address parameters contained within the chunk.
933 * 2.18.3 Solution description
935 * This new text clearly specifies to an implementor the need
936 * to look within the INIT or INIT-ACK. Any implementation that
937 * does not do this, may not be able to establish associations
938 * in certain circumstances.
941 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
942 struct sk_buff *skb,
943 const union sctp_addr *laddr, struct sctp_transport **transportp)
945 struct sctp_association *asoc;
946 union sctp_addr addr;
947 union sctp_addr *paddr = &addr;
948 struct sctphdr *sh = sctp_hdr(skb);
949 union sctp_params params;
950 sctp_init_chunk_t *init;
951 struct sctp_transport *transport;
952 struct sctp_af *af;
955 * This code will NOT touch anything inside the chunk--it is
956 * strictly READ-ONLY.
958 * RFC 2960 3 SCTP packet Format
960 * Multiple chunks can be bundled into one SCTP packet up to
961 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
962 * COMPLETE chunks. These chunks MUST NOT be bundled with any
963 * other chunk in a packet. See Section 6.10 for more details
964 * on chunk bundling.
967 /* Find the start of the TLVs and the end of the chunk. This is
968 * the region we search for address parameters.
970 init = (sctp_init_chunk_t *)skb->data;
972 /* Walk the parameters looking for embedded addresses. */
973 sctp_walk_params(params, init, init_hdr.params) {
975 /* Note: Ignoring hostname addresses. */
976 af = sctp_get_af_specific(param_type2af(params.p->type));
977 if (!af)
978 continue;
980 af->from_addr_param(paddr, params.addr, sh->source, 0);
982 asoc = __sctp_lookup_association(net, laddr, paddr, &transport);
983 if (asoc)
984 return asoc;
987 return NULL;
990 /* ADD-IP, Section 5.2
991 * When an endpoint receives an ASCONF Chunk from the remote peer
992 * special procedures may be needed to identify the association the
993 * ASCONF Chunk is associated with. To properly find the association
994 * the following procedures SHOULD be followed:
996 * D2) If the association is not found, use the address found in the
997 * Address Parameter TLV combined with the port number found in the
998 * SCTP common header. If found proceed to rule D4.
1000 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1001 * address found in the ASCONF Address Parameter TLV of each of the
1002 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1004 static struct sctp_association *__sctp_rcv_asconf_lookup(
1005 struct net *net,
1006 sctp_chunkhdr_t *ch,
1007 const union sctp_addr *laddr,
1008 __be16 peer_port,
1009 struct sctp_transport **transportp)
1011 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
1012 struct sctp_af *af;
1013 union sctp_addr_param *param;
1014 union sctp_addr paddr;
1016 /* Skip over the ADDIP header and find the Address parameter */
1017 param = (union sctp_addr_param *)(asconf + 1);
1019 af = sctp_get_af_specific(param_type2af(param->p.type));
1020 if (unlikely(!af))
1021 return NULL;
1023 af->from_addr_param(&paddr, param, peer_port, 0);
1025 return __sctp_lookup_association(net, laddr, &paddr, transportp);
1029 /* SCTP-AUTH, Section 6.3:
1030 * If the receiver does not find a STCB for a packet containing an AUTH
1031 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1032 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1033 * association.
1035 * This means that any chunks that can help us identify the association need
1036 * to be looked at to find this association.
1038 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
1039 struct sk_buff *skb,
1040 const union sctp_addr *laddr,
1041 struct sctp_transport **transportp)
1043 struct sctp_association *asoc = NULL;
1044 sctp_chunkhdr_t *ch;
1045 int have_auth = 0;
1046 unsigned int chunk_num = 1;
1047 __u8 *ch_end;
1049 /* Walk through the chunks looking for AUTH or ASCONF chunks
1050 * to help us find the association.
1052 ch = (sctp_chunkhdr_t *) skb->data;
1053 do {
1054 /* Break out if chunk length is less then minimal. */
1055 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
1056 break;
1058 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
1059 if (ch_end > skb_tail_pointer(skb))
1060 break;
1062 switch(ch->type) {
1063 case SCTP_CID_AUTH:
1064 have_auth = chunk_num;
1065 break;
1067 case SCTP_CID_COOKIE_ECHO:
1068 /* If a packet arrives containing an AUTH chunk as
1069 * a first chunk, a COOKIE-ECHO chunk as the second
1070 * chunk, and possibly more chunks after them, and
1071 * the receiver does not have an STCB for that
1072 * packet, then authentication is based on
1073 * the contents of the COOKIE- ECHO chunk.
1075 if (have_auth == 1 && chunk_num == 2)
1076 return NULL;
1077 break;
1079 case SCTP_CID_ASCONF:
1080 if (have_auth || net->sctp.addip_noauth)
1081 asoc = __sctp_rcv_asconf_lookup(
1082 net, ch, laddr,
1083 sctp_hdr(skb)->source,
1084 transportp);
1085 default:
1086 break;
1089 if (asoc)
1090 break;
1092 ch = (sctp_chunkhdr_t *) ch_end;
1093 chunk_num++;
1094 } while (ch_end < skb_tail_pointer(skb));
1096 return asoc;
1100 * There are circumstances when we need to look inside the SCTP packet
1101 * for information to help us find the association. Examples
1102 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1103 * chunks.
1105 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
1106 struct sk_buff *skb,
1107 const union sctp_addr *laddr,
1108 struct sctp_transport **transportp)
1110 sctp_chunkhdr_t *ch;
1112 ch = (sctp_chunkhdr_t *) skb->data;
1114 /* The code below will attempt to walk the chunk and extract
1115 * parameter information. Before we do that, we need to verify
1116 * that the chunk length doesn't cause overflow. Otherwise, we'll
1117 * walk off the end.
1119 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
1120 return NULL;
1122 /* If this is INIT/INIT-ACK look inside the chunk too. */
1123 switch (ch->type) {
1124 case SCTP_CID_INIT:
1125 case SCTP_CID_INIT_ACK:
1126 return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
1127 break;
1129 default:
1130 return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
1131 break;
1135 return NULL;
1138 /* Lookup an association for an inbound skb. */
1139 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1140 struct sk_buff *skb,
1141 const union sctp_addr *paddr,
1142 const union sctp_addr *laddr,
1143 struct sctp_transport **transportp)
1145 struct sctp_association *asoc;
1147 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1149 /* Further lookup for INIT/INIT-ACK packets.
1150 * SCTP Implementors Guide, 2.18 Handling of address
1151 * parameters within the INIT or INIT-ACK.
1153 if (!asoc)
1154 asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);
1156 return asoc;