1 /* SCTP kernel implementation
2 * Copyright (c) 1999-2000 Cisco, Inc.
3 * Copyright (c) 1999-2001 Motorola, Inc.
4 * Copyright (c) 2001-2003 International Business Machines, Corp.
5 * Copyright (c) 2001 Intel Corp.
6 * Copyright (c) 2001 Nokia, Inc.
7 * Copyright (c) 2001 La Monte H.P. Yarroll
9 * This file is part of the SCTP kernel implementation
11 * These functions handle all input from the IP layer into SCTP.
13 * This SCTP implementation is free software;
14 * you can redistribute it and/or modify it under the terms of
15 * the GNU General Public License as published by
16 * the Free Software Foundation; either version 2, or (at your option)
19 * This SCTP implementation is distributed in the hope that it
20 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
21 * ************************
22 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23 * See the GNU General Public License for more details.
25 * You should have received a copy of the GNU General Public License
26 * along with GNU CC; see the file COPYING. If not, see
27 * <http://www.gnu.org/licenses/>.
29 * Please send any bug reports or fixes you make to the
31 * lksctp developers <linux-sctp@vger.kernel.org>
33 * Written or modified by:
34 * La Monte H.P. Yarroll <piggy@acm.org>
35 * Karl Knutson <karl@athena.chicago.il.us>
36 * Xingang Guo <xingang.guo@intel.com>
37 * Jon Grimm <jgrimm@us.ibm.com>
38 * Hui Huang <hui.huang@nokia.com>
39 * Daisy Chang <daisyc@us.ibm.com>
40 * Sridhar Samudrala <sri@us.ibm.com>
41 * Ardelle Fan <ardelle.fan@intel.com>
44 #include <linux/types.h>
45 #include <linux/list.h> /* For struct list_head */
46 #include <linux/socket.h>
48 #include <linux/time.h> /* For struct timeval */
49 #include <linux/slab.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
57 #include <net/sctp/checksum.h>
58 #include <net/net_namespace.h>
60 /* Forward declarations for internal helpers. */
61 static int sctp_rcv_ootb(struct sk_buff *);
62 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
64 const union sctp_addr *paddr,
65 const union sctp_addr *laddr,
66 struct sctp_transport **transportp);
67 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
68 const union sctp_addr *laddr);
69 static struct sctp_association *__sctp_lookup_association(
71 const union sctp_addr *local,
72 const union sctp_addr *peer,
73 struct sctp_transport **pt);
75 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
78 /* Calculate the SCTP checksum of an SCTP packet. */
79 static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb)
81 struct sctphdr *sh = sctp_hdr(skb);
82 __le32 cmp = sh->checksum;
83 __le32 val = sctp_compute_cksum(skb, 0);
86 /* CRC failure, dump it. */
87 SCTP_INC_STATS_BH(net, SCTP_MIB_CHECKSUMERRORS);
93 struct sctp_input_cb {
95 struct inet_skb_parm h4;
96 #if IS_ENABLED(CONFIG_IPV6)
97 struct inet6_skb_parm h6;
100 struct sctp_chunk *chunk;
102 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
105 * This is the routine which IP calls when receiving an SCTP packet.
107 int sctp_rcv(struct sk_buff *skb)
110 struct sctp_association *asoc;
111 struct sctp_endpoint *ep = NULL;
112 struct sctp_ep_common *rcvr;
113 struct sctp_transport *transport = NULL;
114 struct sctp_chunk *chunk;
117 union sctp_addr dest;
120 struct net *net = dev_net(skb->dev);
122 if (skb->pkt_type != PACKET_HOST)
125 SCTP_INC_STATS_BH(net, SCTP_MIB_INSCTPPACKS);
127 if (skb_linearize(skb))
132 /* Pull up the IP and SCTP headers. */
133 __skb_pull(skb, skb_transport_offset(skb));
134 if (skb->len < sizeof(struct sctphdr))
137 skb->csum_valid = 0; /* Previous value not applicable */
138 if (skb_csum_unnecessary(skb))
139 __skb_decr_checksum_unnecessary(skb);
140 else if (!sctp_checksum_disable && sctp_rcv_checksum(net, skb) < 0)
144 skb_pull(skb, sizeof(struct sctphdr));
146 /* Make sure we at least have chunk headers worth of data left. */
147 if (skb->len < sizeof(struct sctp_chunkhdr))
150 family = ipver2af(ip_hdr(skb)->version);
151 af = sctp_get_af_specific(family);
155 /* Initialize local addresses for lookups. */
156 af->from_skb(&src, skb, 1);
157 af->from_skb(&dest, skb, 0);
159 /* If the packet is to or from a non-unicast address,
160 * silently discard the packet.
162 * This is not clearly defined in the RFC except in section
163 * 8.4 - OOTB handling. However, based on the book "Stream Control
164 * Transmission Protocol" 2.1, "It is important to note that the
165 * IP address of an SCTP transport address must be a routable
166 * unicast address. In other words, IP multicast addresses and
167 * IP broadcast addresses cannot be used in an SCTP transport
170 if (!af->addr_valid(&src, NULL, skb) ||
171 !af->addr_valid(&dest, NULL, skb))
174 asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
177 ep = __sctp_rcv_lookup_endpoint(net, &dest);
179 /* Retrieve the common input handling substructure. */
180 rcvr = asoc ? &asoc->base : &ep->base;
184 * If a frame arrives on an interface and the receiving socket is
185 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
187 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) {
189 sctp_association_put(asoc);
192 sctp_endpoint_put(ep);
195 sk = net->sctp.ctl_sock;
196 ep = sctp_sk(sk)->ep;
197 sctp_endpoint_hold(ep);
202 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
203 * An SCTP packet is called an "out of the blue" (OOTB)
204 * packet if it is correctly formed, i.e., passed the
205 * receiver's checksum check, but the receiver is not
206 * able to identify the association to which this
210 if (sctp_rcv_ootb(skb)) {
211 SCTP_INC_STATS_BH(net, SCTP_MIB_OUTOFBLUES);
212 goto discard_release;
216 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
217 goto discard_release;
220 if (sk_filter(sk, skb))
221 goto discard_release;
223 /* Create an SCTP packet structure. */
224 chunk = sctp_chunkify(skb, asoc, sk);
226 goto discard_release;
227 SCTP_INPUT_CB(skb)->chunk = chunk;
229 /* Remember what endpoint is to handle this packet. */
232 /* Remember the SCTP header. */
233 chunk->sctp_hdr = sh;
235 /* Set the source and destination addresses of the incoming chunk. */
236 sctp_init_addrs(chunk, &src, &dest);
238 /* Remember where we came from. */
239 chunk->transport = transport;
241 /* Acquire access to the sock lock. Note: We are safe from other
242 * bottom halves on this lock, but a user may be in the lock too,
243 * so check if it is busy.
247 if (sk != rcvr->sk) {
248 /* Our cached sk is different from the rcvr->sk. This is
249 * because migrate()/accept() may have moved the association
250 * to a new socket and released all the sockets. So now we
251 * are holding a lock on the old socket while the user may
252 * be doing something with the new socket. Switch our veiw
260 if (sock_owned_by_user(sk)) {
261 if (sctp_add_backlog(sk, skb)) {
263 sctp_chunk_free(chunk);
264 skb = NULL; /* sctp_chunk_free already freed the skb */
265 goto discard_release;
267 SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_BACKLOG);
269 SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ);
270 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
275 /* Release the asoc/ep ref we took in the lookup calls. */
277 sctp_association_put(asoc);
279 sctp_endpoint_put(ep);
284 SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_DISCARDS);
289 /* Release the asoc/ep ref we took in the lookup calls. */
291 sctp_association_put(asoc);
293 sctp_endpoint_put(ep);
298 /* Process the backlog queue of the socket. Every skb on
299 * the backlog holds a ref on an association or endpoint.
300 * We hold this ref throughout the state machine to make
301 * sure that the structure we need is still around.
303 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
305 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
306 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
307 struct sctp_ep_common *rcvr = NULL;
312 /* If the rcvr is dead then the association or endpoint
313 * has been deleted and we can safely drop the chunk
314 * and refs that we are holding.
317 sctp_chunk_free(chunk);
321 if (unlikely(rcvr->sk != sk)) {
322 /* In this case, the association moved from one socket to
323 * another. We are currently sitting on the backlog of the
324 * old socket, so we need to move.
325 * However, since we are here in the process context we
326 * need to take make sure that the user doesn't own
327 * the new socket when we process the packet.
328 * If the new socket is user-owned, queue the chunk to the
329 * backlog of the new socket without dropping any refs.
330 * Otherwise, we can safely push the chunk on the inqueue.
336 if (sock_owned_by_user(sk)) {
337 if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
338 sctp_chunk_free(chunk);
342 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_association_put(sctp_assoc(rcvr));
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_ep_common *rcvr = chunk->rcvr;
371 ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
373 /* Hold the assoc/ep while hanging on the backlog queue.
374 * This way, we know structures we need will not disappear
377 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
378 sctp_association_hold(sctp_assoc(rcvr));
379 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
380 sctp_endpoint_hold(sctp_ep(rcvr));
388 /* Handle icmp frag needed error. */
389 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
390 struct sctp_transport *t, __u32 pmtu)
392 if (!t || (t->pathmtu <= pmtu))
395 if (sock_owned_by_user(sk)) {
396 asoc->pmtu_pending = 1;
401 if (t->param_flags & SPP_PMTUD_ENABLE) {
402 /* Update transports view of the MTU */
403 sctp_transport_update_pmtu(sk, t, pmtu);
405 /* Update association pmtu. */
406 sctp_assoc_sync_pmtu(sk, asoc);
409 /* Retransmit with the new pmtu setting.
410 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
411 * Needed will never be sent, but if a message was sent before
412 * PMTU discovery was disabled that was larger than the PMTU, it
413 * would not be fragmented, so it must be re-transmitted fragmented.
415 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
418 void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
421 struct dst_entry *dst;
425 dst = sctp_transport_dst_check(t);
427 dst->ops->redirect(dst, sk, skb);
431 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
433 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
434 * or a "Protocol Unreachable" treat this message as an abort
435 * with the T bit set.
437 * This function sends an event to the state machine, which will abort the
441 void sctp_icmp_proto_unreachable(struct sock *sk,
442 struct sctp_association *asoc,
443 struct sctp_transport *t)
445 if (sock_owned_by_user(sk)) {
446 if (timer_pending(&t->proto_unreach_timer))
449 if (!mod_timer(&t->proto_unreach_timer,
451 sctp_association_hold(asoc);
454 struct net *net = sock_net(sk);
456 pr_debug("%s: unrecognized next header type "
457 "encountered!\n", __func__);
459 if (del_timer(&t->proto_unreach_timer))
460 sctp_association_put(asoc);
462 sctp_do_sm(net, SCTP_EVENT_T_OTHER,
463 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
464 asoc->state, asoc->ep, asoc, t,
469 /* Common lookup code for icmp/icmpv6 error handler. */
470 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
471 struct sctphdr *sctphdr,
472 struct sctp_association **app,
473 struct sctp_transport **tpp)
475 union sctp_addr saddr;
476 union sctp_addr daddr;
478 struct sock *sk = NULL;
479 struct sctp_association *asoc;
480 struct sctp_transport *transport = NULL;
481 struct sctp_init_chunk *chunkhdr;
482 __u32 vtag = ntohl(sctphdr->vtag);
483 int len = skb->len - ((void *)sctphdr - (void *)skb->data);
485 *app = NULL; *tpp = NULL;
487 af = sctp_get_af_specific(family);
492 /* Initialize local addresses for lookups. */
493 af->from_skb(&saddr, skb, 1);
494 af->from_skb(&daddr, skb, 0);
496 /* Look for an association that matches the incoming ICMP error
499 asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport);
505 /* RFC 4960, Appendix C. ICMP Handling
507 * ICMP6) An implementation MUST validate that the Verification Tag
508 * contained in the ICMP message matches the Verification Tag of
509 * the peer. If the Verification Tag is not 0 and does NOT
510 * match, discard the ICMP message. If it is 0 and the ICMP
511 * message contains enough bytes to verify that the chunk type is
512 * an INIT chunk and that the Initiate Tag matches the tag of the
513 * peer, continue with ICMP7. If the ICMP message is too short
514 * or the chunk type or the Initiate Tag does not match, silently
515 * discard the packet.
518 chunkhdr = (void *)sctphdr + sizeof(struct sctphdr);
519 if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
521 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
522 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
525 } else if (vtag != asoc->c.peer_vtag) {
531 /* If too many ICMPs get dropped on busy
532 * servers this needs to be solved differently.
534 if (sock_owned_by_user(sk))
535 NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
542 sctp_association_put(asoc);
546 /* Common cleanup code for icmp/icmpv6 error handler. */
547 void sctp_err_finish(struct sock *sk, struct sctp_association *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;
575 struct sctp_association *asoc = NULL;
576 struct sctp_transport *transport;
577 struct inet_sock *inet;
578 __u16 saveip, savesctp;
580 struct net *net = dev_net(skb->dev);
582 /* Fix up skb to look at the embedded net header. */
583 saveip = skb->network_header;
584 savesctp = skb->transport_header;
585 skb_reset_network_header(skb);
586 skb_set_transport_header(skb, ihlen);
587 sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
588 /* Put back, the original values. */
589 skb->network_header = saveip;
590 skb->transport_header = savesctp;
592 ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
595 /* Warning: The sock lock is held. Remember to call
600 case ICMP_PARAMETERPROB:
603 case ICMP_DEST_UNREACH:
604 if (code > NR_ICMP_UNREACH)
607 /* PMTU discovery (RFC1191) */
608 if (ICMP_FRAG_NEEDED == code) {
609 sctp_icmp_frag_needed(sk, asoc, transport, info);
612 if (ICMP_PROT_UNREACH == code) {
613 sctp_icmp_proto_unreachable(sk, asoc,
618 err = icmp_err_convert[code].errno;
620 case ICMP_TIME_EXCEEDED:
621 /* Ignore any time exceeded errors due to fragment reassembly
624 if (ICMP_EXC_FRAGTIME == code)
630 sctp_icmp_redirect(sk, transport, skb);
631 /* Fall through to out_unlock. */
637 if (!sock_owned_by_user(sk) && inet->recverr) {
639 sk->sk_error_report(sk);
640 } else { /* Only an error on timeout */
641 sk->sk_err_soft = err;
645 sctp_err_finish(sk, asoc);
649 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
651 * This function scans all the chunks in the OOTB packet to determine if
652 * the packet should be discarded right away. If a response might be needed
653 * for this packet, or, if further processing is possible, the packet will
654 * be queued to a proper inqueue for the next phase of handling.
657 * Return 0 - If further processing is needed.
658 * Return 1 - If the packet can be discarded right away.
660 static int sctp_rcv_ootb(struct sk_buff *skb)
665 ch = (sctp_chunkhdr_t *) skb->data;
667 /* Scan through all the chunks in the packet. */
669 /* Break out if chunk length is less then minimal. */
670 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
673 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
674 if (ch_end > skb_tail_pointer(skb))
677 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
678 * receiver MUST silently discard the OOTB packet and take no
681 if (SCTP_CID_ABORT == ch->type)
684 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
685 * chunk, the receiver should silently discard the packet
686 * and take no further action.
688 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
692 * This will discard packets with INIT chunk bundled as
693 * subsequent chunks in the packet. When INIT is first,
694 * the normal INIT processing will discard the chunk.
696 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
699 ch = (sctp_chunkhdr_t *) ch_end;
700 } while (ch_end < skb_tail_pointer(skb));
708 /* Insert endpoint into the hash table. */
709 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
711 struct net *net = sock_net(ep->base.sk);
712 struct sctp_ep_common *epb;
713 struct sctp_hashbucket *head;
717 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
718 head = &sctp_ep_hashtable[epb->hashent];
720 write_lock(&head->lock);
721 hlist_add_head(&epb->node, &head->chain);
722 write_unlock(&head->lock);
725 /* Add an endpoint to the hash. Local BH-safe. */
726 void sctp_hash_endpoint(struct sctp_endpoint *ep)
729 __sctp_hash_endpoint(ep);
733 /* Remove endpoint from the hash table. */
734 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
736 struct net *net = sock_net(ep->base.sk);
737 struct sctp_hashbucket *head;
738 struct sctp_ep_common *epb;
742 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
744 head = &sctp_ep_hashtable[epb->hashent];
746 write_lock(&head->lock);
747 hlist_del_init(&epb->node);
748 write_unlock(&head->lock);
751 /* Remove endpoint from the hash. Local BH-safe. */
752 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
755 __sctp_unhash_endpoint(ep);
759 /* Look up an endpoint. */
760 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
761 const union sctp_addr *laddr)
763 struct sctp_hashbucket *head;
764 struct sctp_ep_common *epb;
765 struct sctp_endpoint *ep;
768 hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
769 head = &sctp_ep_hashtable[hash];
770 read_lock(&head->lock);
771 sctp_for_each_hentry(epb, &head->chain) {
773 if (sctp_endpoint_is_match(ep, net, laddr))
777 ep = sctp_sk(net->sctp.ctl_sock)->ep;
780 sctp_endpoint_hold(ep);
781 read_unlock(&head->lock);
785 /* rhashtable for transport */
786 struct sctp_hash_cmp_arg {
787 const struct sctp_endpoint *ep;
788 const union sctp_addr *laddr;
789 const union sctp_addr *paddr;
790 const struct net *net;
793 static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
796 const struct sctp_hash_cmp_arg *x = arg->key;
797 const struct sctp_transport *t = ptr;
798 struct sctp_association *asoc = t->asoc;
799 const struct net *net = x->net;
801 if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr))
803 if (!net_eq(sock_net(asoc->base.sk), net))
806 if (x->ep != asoc->ep)
809 if (x->laddr->v4.sin_port != htons(asoc->base.bind_addr.port))
811 if (!sctp_bind_addr_match(&asoc->base.bind_addr,
812 x->laddr, sctp_sk(asoc->base.sk)))
819 static inline u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
821 const struct sctp_transport *t = data;
822 const union sctp_addr *paddr = &t->ipaddr;
823 const struct net *net = sock_net(t->asoc->base.sk);
824 u16 lport = htons(t->asoc->base.bind_addr.port);
827 if (paddr->sa.sa_family == AF_INET6)
828 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
830 addr = paddr->v4.sin_addr.s_addr;
832 return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 |
833 (__force __u32)lport, net_hash_mix(net), seed);
836 static inline u32 sctp_hash_key(const void *data, u32 len, u32 seed)
838 const struct sctp_hash_cmp_arg *x = data;
839 const union sctp_addr *paddr = x->paddr;
840 const struct net *net = x->net;
844 lport = x->ep ? htons(x->ep->base.bind_addr.port) :
845 x->laddr->v4.sin_port;
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 rhashtable_init(&sctp_transport_hashtable, &sctp_hash_params);
868 void sctp_transport_hashtable_destroy(void)
870 rhashtable_destroy(&sctp_transport_hashtable);
873 void sctp_hash_transport(struct sctp_transport *t)
875 struct sctp_hash_cmp_arg arg;
880 arg.ep = t->asoc->ep;
881 arg.paddr = &t->ipaddr;
882 arg.net = sock_net(t->asoc->base.sk);
885 if (rhashtable_lookup_insert_key(&sctp_transport_hashtable, &arg,
886 &t->node, sctp_hash_params) == -EBUSY)
890 void sctp_unhash_transport(struct sctp_transport *t)
895 rhashtable_remove_fast(&sctp_transport_hashtable, &t->node,
899 struct sctp_transport *sctp_addrs_lookup_transport(
901 const union sctp_addr *laddr,
902 const union sctp_addr *paddr)
904 struct sctp_hash_cmp_arg arg = {
911 return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
915 struct sctp_transport *sctp_epaddr_lookup_transport(
916 const struct sctp_endpoint *ep,
917 const union sctp_addr *paddr)
919 struct net *net = sock_net(ep->base.sk);
920 struct sctp_hash_cmp_arg arg = {
926 return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
930 /* Look up an association. */
931 static struct sctp_association *__sctp_lookup_association(
933 const union sctp_addr *local,
934 const union sctp_addr *peer,
935 struct sctp_transport **pt)
937 struct sctp_transport *t;
939 t = sctp_addrs_lookup_transport(net, local, peer);
943 sctp_association_hold(t->asoc);
949 /* Look up an association. protected by RCU read lock */
951 struct sctp_association *sctp_lookup_association(struct net *net,
952 const union sctp_addr *laddr,
953 const union sctp_addr *paddr,
954 struct sctp_transport **transportp)
956 struct sctp_association *asoc;
959 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
965 /* Is there an association matching the given local and peer addresses? */
966 int sctp_has_association(struct net *net,
967 const union sctp_addr *laddr,
968 const union sctp_addr *paddr)
970 struct sctp_association *asoc;
971 struct sctp_transport *transport;
973 if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) {
974 sctp_association_put(asoc);
982 * SCTP Implementors Guide, 2.18 Handling of address
983 * parameters within the INIT or INIT-ACK.
985 * D) When searching for a matching TCB upon reception of an INIT
986 * or INIT-ACK chunk the receiver SHOULD use not only the
987 * source address of the packet (containing the INIT or
988 * INIT-ACK) but the receiver SHOULD also use all valid
989 * address parameters contained within the chunk.
991 * 2.18.3 Solution description
993 * This new text clearly specifies to an implementor the need
994 * to look within the INIT or INIT-ACK. Any implementation that
995 * does not do this, may not be able to establish associations
996 * in certain circumstances.
999 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
1000 struct sk_buff *skb,
1001 const union sctp_addr *laddr, struct sctp_transport **transportp)
1003 struct sctp_association *asoc;
1004 union sctp_addr addr;
1005 union sctp_addr *paddr = &addr;
1006 struct sctphdr *sh = sctp_hdr(skb);
1007 union sctp_params params;
1008 sctp_init_chunk_t *init;
1009 struct sctp_transport *transport;
1013 * This code will NOT touch anything inside the chunk--it is
1014 * strictly READ-ONLY.
1016 * RFC 2960 3 SCTP packet Format
1018 * Multiple chunks can be bundled into one SCTP packet up to
1019 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
1020 * COMPLETE chunks. These chunks MUST NOT be bundled with any
1021 * other chunk in a packet. See Section 6.10 for more details
1022 * on chunk bundling.
1025 /* Find the start of the TLVs and the end of the chunk. This is
1026 * the region we search for address parameters.
1028 init = (sctp_init_chunk_t *)skb->data;
1030 /* Walk the parameters looking for embedded addresses. */
1031 sctp_walk_params(params, init, init_hdr.params) {
1033 /* Note: Ignoring hostname addresses. */
1034 af = sctp_get_af_specific(param_type2af(params.p->type));
1038 af->from_addr_param(paddr, params.addr, sh->source, 0);
1040 asoc = __sctp_lookup_association(net, laddr, paddr, &transport);
1048 /* ADD-IP, Section 5.2
1049 * When an endpoint receives an ASCONF Chunk from the remote peer
1050 * special procedures may be needed to identify the association the
1051 * ASCONF Chunk is associated with. To properly find the association
1052 * the following procedures SHOULD be followed:
1054 * D2) If the association is not found, use the address found in the
1055 * Address Parameter TLV combined with the port number found in the
1056 * SCTP common header. If found proceed to rule D4.
1058 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1059 * address found in the ASCONF Address Parameter TLV of each of the
1060 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1062 static struct sctp_association *__sctp_rcv_asconf_lookup(
1064 sctp_chunkhdr_t *ch,
1065 const union sctp_addr *laddr,
1067 struct sctp_transport **transportp)
1069 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
1071 union sctp_addr_param *param;
1072 union sctp_addr paddr;
1074 /* Skip over the ADDIP header and find the Address parameter */
1075 param = (union sctp_addr_param *)(asconf + 1);
1077 af = sctp_get_af_specific(param_type2af(param->p.type));
1081 af->from_addr_param(&paddr, param, peer_port, 0);
1083 return __sctp_lookup_association(net, laddr, &paddr, transportp);
1087 /* SCTP-AUTH, Section 6.3:
1088 * If the receiver does not find a STCB for a packet containing an AUTH
1089 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1090 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1093 * This means that any chunks that can help us identify the association need
1094 * to be looked at to find this association.
1096 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
1097 struct sk_buff *skb,
1098 const union sctp_addr *laddr,
1099 struct sctp_transport **transportp)
1101 struct sctp_association *asoc = NULL;
1102 sctp_chunkhdr_t *ch;
1104 unsigned int chunk_num = 1;
1107 /* Walk through the chunks looking for AUTH or ASCONF chunks
1108 * to help us find the association.
1110 ch = (sctp_chunkhdr_t *) skb->data;
1112 /* Break out if chunk length is less then minimal. */
1113 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
1116 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
1117 if (ch_end > skb_tail_pointer(skb))
1122 have_auth = chunk_num;
1125 case SCTP_CID_COOKIE_ECHO:
1126 /* If a packet arrives containing an AUTH chunk as
1127 * a first chunk, a COOKIE-ECHO chunk as the second
1128 * chunk, and possibly more chunks after them, and
1129 * the receiver does not have an STCB for that
1130 * packet, then authentication is based on
1131 * the contents of the COOKIE- ECHO chunk.
1133 if (have_auth == 1 && chunk_num == 2)
1137 case SCTP_CID_ASCONF:
1138 if (have_auth || net->sctp.addip_noauth)
1139 asoc = __sctp_rcv_asconf_lookup(
1141 sctp_hdr(skb)->source,
1150 ch = (sctp_chunkhdr_t *) ch_end;
1152 } while (ch_end < skb_tail_pointer(skb));
1158 * There are circumstances when we need to look inside the SCTP packet
1159 * for information to help us find the association. Examples
1160 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1163 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
1164 struct sk_buff *skb,
1165 const union sctp_addr *laddr,
1166 struct sctp_transport **transportp)
1168 sctp_chunkhdr_t *ch;
1170 ch = (sctp_chunkhdr_t *) skb->data;
1172 /* The code below will attempt to walk the chunk and extract
1173 * parameter information. Before we do that, we need to verify
1174 * that the chunk length doesn't cause overflow. Otherwise, we'll
1177 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
1180 /* If this is INIT/INIT-ACK look inside the chunk too. */
1181 if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
1182 return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
1184 return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
1187 /* Lookup an association for an inbound skb. */
1188 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1189 struct sk_buff *skb,
1190 const union sctp_addr *paddr,
1191 const union sctp_addr *laddr,
1192 struct sctp_transport **transportp)
1194 struct sctp_association *asoc;
1196 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1198 /* Further lookup for INIT/INIT-ACK packets.
1199 * SCTP Implementors Guide, 2.18 Handling of address
1200 * parameters within the INIT or INIT-ACK.
1203 asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);