1 /* SCTP kernel implementation
2 * Copyright (c) 1999-2000 Cisco, Inc.
3 * Copyright (c) 1999-2001 Motorola, Inc.
4 * Copyright (c) 2001-2003 International Business Machines, Corp.
5 * Copyright (c) 2001 Intel Corp.
6 * Copyright (c) 2001 Nokia, Inc.
7 * Copyright (c) 2001 La Monte H.P. Yarroll
9 * This file is part of the SCTP kernel implementation
11 * These functions handle all input from the IP layer into SCTP.
13 * This SCTP implementation is free software;
14 * you can redistribute it and/or modify it under the terms of
15 * the GNU General Public License as published by
16 * the Free Software Foundation; either version 2, or (at your option)
19 * This SCTP implementation is distributed in the hope that it
20 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
21 * ************************
22 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23 * See the GNU General Public License for more details.
25 * You should have received a copy of the GNU General Public License
26 * along with GNU CC; see the file COPYING. If not, see
27 * <http://www.gnu.org/licenses/>.
29 * Please send any bug reports or fixes you make to the
31 * lksctp developers <linux-sctp@vger.kernel.org>
33 * Written or modified by:
34 * La Monte H.P. Yarroll <piggy@acm.org>
35 * Karl Knutson <karl@athena.chicago.il.us>
36 * Xingang Guo <xingang.guo@intel.com>
37 * Jon Grimm <jgrimm@us.ibm.com>
38 * Hui Huang <hui.huang@nokia.com>
39 * Daisy Chang <daisyc@us.ibm.com>
40 * Sridhar Samudrala <sri@us.ibm.com>
41 * Ardelle Fan <ardelle.fan@intel.com>
44 #include <linux/types.h>
45 #include <linux/list.h> /* For struct list_head */
46 #include <linux/socket.h>
48 #include <linux/time.h> /* For struct timeval */
49 #include <linux/slab.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
57 #include <net/sctp/checksum.h>
58 #include <net/net_namespace.h>
60 /* Forward declarations for internal helpers. */
61 static int sctp_rcv_ootb(struct sk_buff *);
62 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
64 const union sctp_addr *paddr,
65 const union sctp_addr *laddr,
66 struct sctp_transport **transportp);
67 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
68 const union sctp_addr *laddr);
69 static struct sctp_association *__sctp_lookup_association(
71 const union sctp_addr *local,
72 const union sctp_addr *peer,
73 struct sctp_transport **pt);
75 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
78 /* Calculate the SCTP checksum of an SCTP packet. */
79 static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb)
81 struct sctphdr *sh = sctp_hdr(skb);
82 __le32 cmp = sh->checksum;
83 __le32 val = sctp_compute_cksum(skb, 0);
86 /* CRC failure, dump it. */
87 __SCTP_INC_STATS(net, SCTP_MIB_CHECKSUMERRORS);
94 * This is the routine which IP calls when receiving an SCTP packet.
96 int sctp_rcv(struct sk_buff *skb)
99 struct sctp_association *asoc;
100 struct sctp_endpoint *ep = NULL;
101 struct sctp_ep_common *rcvr;
102 struct sctp_transport *transport = NULL;
103 struct sctp_chunk *chunk;
105 union sctp_addr dest;
109 struct net *net = dev_net(skb->dev);
111 if (skb->pkt_type != PACKET_HOST)
114 __SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS);
116 /* If packet is too small to contain a single chunk, let's not
117 * waste time on it anymore.
119 if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) +
120 skb_transport_offset(skb))
123 /* If the packet is fragmented and we need to do crc checking,
124 * it's better to just linearize it otherwise crc computing
127 if ((!(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) &&
128 skb_linearize(skb)) ||
129 !pskb_may_pull(skb, sizeof(struct sctphdr)))
132 /* Pull up the IP header. */
133 __skb_pull(skb, skb_transport_offset(skb));
135 skb->csum_valid = 0; /* Previous value not applicable */
136 if (skb_csum_unnecessary(skb))
137 __skb_decr_checksum_unnecessary(skb);
138 else if (!sctp_checksum_disable &&
139 !(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) &&
140 sctp_rcv_checksum(net, skb) < 0)
144 __skb_pull(skb, sizeof(struct sctphdr));
146 family = ipver2af(ip_hdr(skb)->version);
147 af = sctp_get_af_specific(family);
150 SCTP_INPUT_CB(skb)->af = af;
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
167 if (!af->addr_valid(&src, NULL, skb) ||
168 !af->addr_valid(&dest, NULL, skb))
171 asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
174 ep = __sctp_rcv_lookup_endpoint(net, &dest);
176 /* Retrieve the common input handling substructure. */
177 rcvr = asoc ? &asoc->base : &ep->base;
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 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
185 if (bound_dev_if && (bound_dev_if != af->skb_iif(skb))) {
187 sctp_transport_put(transport);
191 sctp_endpoint_put(ep);
194 sk = net->sctp.ctl_sock;
195 ep = sctp_sk(sk)->ep;
196 sctp_endpoint_hold(ep);
201 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
202 * An SCTP packet is called an "out of the blue" (OOTB)
203 * packet if it is correctly formed, i.e., passed the
204 * receiver's checksum check, but the receiver is not
205 * able to identify the association to which this
209 if (sctp_rcv_ootb(skb)) {
210 __SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
211 goto discard_release;
215 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
216 goto discard_release;
219 if (sk_filter(sk, skb))
220 goto discard_release;
222 /* Create an SCTP packet structure. */
223 chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC);
225 goto discard_release;
226 SCTP_INPUT_CB(skb)->chunk = chunk;
228 /* Remember what endpoint is to handle this packet. */
231 /* Remember the SCTP header. */
232 chunk->sctp_hdr = sctp_hdr(skb);
234 /* Set the source and destination addresses of the incoming chunk. */
235 sctp_init_addrs(chunk, &src, &dest);
237 /* Remember where we came from. */
238 chunk->transport = transport;
240 /* Acquire access to the sock lock. Note: We are safe from other
241 * bottom halves on this lock, but a user may be in the lock too,
242 * so check if it is busy.
246 if (sk != rcvr->sk) {
247 /* Our cached sk is different from the rcvr->sk. This is
248 * because migrate()/accept() may have moved the association
249 * to a new socket and released all the sockets. So now we
250 * are holding a lock on the old socket while the user may
251 * be doing something with the new socket. Switch our veiw
259 if (sock_owned_by_user(sk)) {
260 if (sctp_add_backlog(sk, skb)) {
262 sctp_chunk_free(chunk);
263 skb = NULL; /* sctp_chunk_free already freed the skb */
264 goto discard_release;
266 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG);
268 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ);
269 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
274 /* Release the asoc/ep ref we took in the lookup calls. */
276 sctp_transport_put(transport);
278 sctp_endpoint_put(ep);
283 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
288 /* Release the asoc/ep ref we took in the lookup calls. */
290 sctp_transport_put(transport);
292 sctp_endpoint_put(ep);
297 /* Process the backlog queue of the socket. Every skb on
298 * the backlog holds a ref on an association or endpoint.
299 * We hold this ref throughout the state machine to make
300 * sure that the structure we need is still around.
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 = &chunk->rcvr->inqueue;
306 struct sctp_transport *t = chunk->transport;
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.
337 if (sock_owned_by_user(sk)) {
338 if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
339 sctp_chunk_free(chunk);
343 sctp_inq_push(inqueue, chunk);
348 /* If the chunk was backloged again, don't drop refs */
352 sctp_inq_push(inqueue, chunk);
356 /* Release the refs we took in sctp_add_backlog */
357 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
358 sctp_transport_put(t);
359 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
360 sctp_endpoint_put(sctp_ep(rcvr));
367 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
369 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
370 struct sctp_transport *t = chunk->transport;
371 struct sctp_ep_common *rcvr = chunk->rcvr;
374 ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
376 /* Hold the assoc/ep while hanging on the backlog queue.
377 * This way, we know structures we need will not disappear
380 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
381 sctp_transport_hold(t);
382 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
383 sctp_endpoint_hold(sctp_ep(rcvr));
391 /* Handle icmp frag needed error. */
392 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
393 struct sctp_transport *t, __u32 pmtu)
395 if (!t || (t->pathmtu <= pmtu))
398 if (sock_owned_by_user(sk)) {
399 asoc->pmtu_pending = 1;
404 if (t->param_flags & SPP_PMTUD_ENABLE) {
405 /* Update transports view of the MTU */
406 sctp_transport_update_pmtu(sk, t, pmtu);
408 /* Update association pmtu. */
409 sctp_assoc_sync_pmtu(sk, asoc);
412 /* Retransmit with the new pmtu setting.
413 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
414 * Needed will never be sent, but if a message was sent before
415 * PMTU discovery was disabled that was larger than the PMTU, it
416 * would not be fragmented, so it must be re-transmitted fragmented.
418 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
421 void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
424 struct dst_entry *dst;
426 if (sock_owned_by_user(sk) || !t)
428 dst = sctp_transport_dst_check(t);
430 dst->ops->redirect(dst, sk, skb);
434 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
436 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
437 * or a "Protocol Unreachable" treat this message as an abort
438 * with the T bit set.
440 * This function sends an event to the state machine, which will abort the
444 void sctp_icmp_proto_unreachable(struct sock *sk,
445 struct sctp_association *asoc,
446 struct sctp_transport *t)
448 if (sock_owned_by_user(sk)) {
449 if (timer_pending(&t->proto_unreach_timer))
452 if (!mod_timer(&t->proto_unreach_timer,
454 sctp_transport_hold(t);
457 struct net *net = sock_net(sk);
459 pr_debug("%s: unrecognized next header type "
460 "encountered!\n", __func__);
462 if (del_timer(&t->proto_unreach_timer))
463 sctp_transport_put(t);
465 sctp_do_sm(net, SCTP_EVENT_T_OTHER,
466 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
467 asoc->state, asoc->ep, asoc, t,
472 /* Common lookup code for icmp/icmpv6 error handler. */
473 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
474 struct sctphdr *sctphdr,
475 struct sctp_association **app,
476 struct sctp_transport **tpp)
478 struct sctp_init_chunk *chunkhdr, _chunkhdr;
479 union sctp_addr saddr;
480 union sctp_addr daddr;
482 struct sock *sk = NULL;
483 struct sctp_association *asoc;
484 struct sctp_transport *transport = NULL;
485 __u32 vtag = ntohl(sctphdr->vtag);
487 *app = NULL; *tpp = NULL;
489 af = sctp_get_af_specific(family);
494 /* Initialize local addresses for lookups. */
495 af->from_skb(&saddr, skb, 1);
496 af->from_skb(&daddr, skb, 0);
498 /* Look for an association that matches the incoming ICMP error
501 asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport);
507 /* RFC 4960, Appendix C. ICMP Handling
509 * ICMP6) An implementation MUST validate that the Verification Tag
510 * contained in the ICMP message matches the Verification Tag of
511 * the peer. If the Verification Tag is not 0 and does NOT
512 * match, discard the ICMP message. If it is 0 and the ICMP
513 * message contains enough bytes to verify that the chunk type is
514 * an INIT chunk and that the Initiate Tag matches the tag of the
515 * peer, continue with ICMP7. If the ICMP message is too short
516 * or the chunk type or the Initiate Tag does not match, silently
517 * discard the packet.
520 /* chunk header + first 4 octects of init header */
521 chunkhdr = skb_header_pointer(skb, skb_transport_offset(skb) +
522 sizeof(struct sctphdr),
523 sizeof(struct sctp_chunkhdr) +
524 sizeof(__be32), &_chunkhdr);
526 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
527 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag)
530 } else if (vtag != asoc->c.peer_vtag) {
536 /* If too many ICMPs get dropped on busy
537 * servers this needs to be solved differently.
539 if (sock_owned_by_user(sk))
540 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
547 sctp_transport_put(transport);
551 /* Common cleanup code for icmp/icmpv6 error handler. */
552 void sctp_err_finish(struct sock *sk, struct sctp_transport *t)
555 sctp_transport_put(t);
559 * This routine is called by the ICMP module when it gets some
560 * sort of error condition. If err < 0 then the socket should
561 * be closed and the error returned to the user. If err > 0
562 * it's just the icmp type << 8 | icmp code. After adjustment
563 * header points to the first 8 bytes of the sctp header. We need
564 * to find the appropriate port.
566 * The locking strategy used here is very "optimistic". When
567 * someone else accesses the socket the ICMP is just dropped
568 * and for some paths there is no check at all.
569 * A more general error queue to queue errors for later handling
570 * is probably better.
573 void sctp_v4_err(struct sk_buff *skb, __u32 info)
575 const struct iphdr *iph = (const struct iphdr *)skb->data;
576 const int ihlen = iph->ihl * 4;
577 const int type = icmp_hdr(skb)->type;
578 const int code = icmp_hdr(skb)->code;
580 struct sctp_association *asoc = NULL;
581 struct sctp_transport *transport;
582 struct inet_sock *inet;
583 __u16 saveip, savesctp;
585 struct net *net = dev_net(skb->dev);
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;
597 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
600 /* Warning: The sock lock is held. Remember to call
605 case ICMP_PARAMETERPROB:
608 case ICMP_DEST_UNREACH:
609 if (code > NR_ICMP_UNREACH)
612 /* PMTU discovery (RFC1191) */
613 if (ICMP_FRAG_NEEDED == code) {
614 sctp_icmp_frag_needed(sk, asoc, transport,
618 if (ICMP_PROT_UNREACH == code) {
619 sctp_icmp_proto_unreachable(sk, asoc,
624 err = icmp_err_convert[code].errno;
626 case ICMP_TIME_EXCEEDED:
627 /* Ignore any time exceeded errors due to fragment reassembly
630 if (ICMP_EXC_FRAGTIME == code)
636 sctp_icmp_redirect(sk, transport, skb);
637 /* Fall through to out_unlock. */
643 if (!sock_owned_by_user(sk) && inet->recverr) {
645 sk->sk_error_report(sk);
646 } else { /* Only an error on timeout */
647 sk->sk_err_soft = err;
651 sctp_err_finish(sk, transport);
655 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
657 * This function scans all the chunks in the OOTB packet to determine if
658 * the packet should be discarded right away. If a response might be needed
659 * for this packet, or, if further processing is possible, the packet will
660 * be queued to a proper inqueue for the next phase of handling.
663 * Return 0 - If further processing is needed.
664 * Return 1 - If the packet can be discarded right away.
666 static int sctp_rcv_ootb(struct sk_buff *skb)
668 sctp_chunkhdr_t *ch, _ch;
669 int ch_end, offset = 0;
671 /* Scan through all the chunks in the packet. */
673 /* Make sure we have at least the header there */
674 if (offset + sizeof(sctp_chunkhdr_t) > skb->len)
677 ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch);
679 /* Break out if chunk length is less then minimal. */
680 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
683 ch_end = offset + SCTP_PAD4(ntohs(ch->length));
684 if (ch_end > skb->len)
687 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
688 * receiver MUST silently discard the OOTB packet and take no
691 if (SCTP_CID_ABORT == ch->type)
694 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
695 * chunk, the receiver should silently discard the packet
696 * and take no further action.
698 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
702 * This will discard packets with INIT chunk bundled as
703 * subsequent chunks in the packet. When INIT is first,
704 * the normal INIT processing will discard the chunk.
706 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
710 } while (ch_end < skb->len);
718 /* Insert endpoint into the hash table. */
719 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
721 struct net *net = sock_net(ep->base.sk);
722 struct sctp_ep_common *epb;
723 struct sctp_hashbucket *head;
727 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
728 head = &sctp_ep_hashtable[epb->hashent];
730 write_lock(&head->lock);
731 hlist_add_head(&epb->node, &head->chain);
732 write_unlock(&head->lock);
735 /* Add an endpoint to the hash. Local BH-safe. */
736 void sctp_hash_endpoint(struct sctp_endpoint *ep)
739 __sctp_hash_endpoint(ep);
743 /* Remove endpoint from the hash table. */
744 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
746 struct net *net = sock_net(ep->base.sk);
747 struct sctp_hashbucket *head;
748 struct sctp_ep_common *epb;
752 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
754 head = &sctp_ep_hashtable[epb->hashent];
756 write_lock(&head->lock);
757 hlist_del_init(&epb->node);
758 write_unlock(&head->lock);
761 /* Remove endpoint from the hash. Local BH-safe. */
762 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
765 __sctp_unhash_endpoint(ep);
769 /* Look up an endpoint. */
770 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
771 const union sctp_addr *laddr)
773 struct sctp_hashbucket *head;
774 struct sctp_ep_common *epb;
775 struct sctp_endpoint *ep;
778 hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
779 head = &sctp_ep_hashtable[hash];
780 read_lock(&head->lock);
781 sctp_for_each_hentry(epb, &head->chain) {
783 if (sctp_endpoint_is_match(ep, net, laddr))
787 ep = sctp_sk(net->sctp.ctl_sock)->ep;
790 sctp_endpoint_hold(ep);
791 read_unlock(&head->lock);
795 /* rhashtable for transport */
796 struct sctp_hash_cmp_arg {
797 const struct sctp_endpoint *ep;
798 const union sctp_addr *laddr;
799 const union sctp_addr *paddr;
800 const struct net *net;
803 static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
806 struct sctp_transport *t = (struct sctp_transport *)ptr;
807 const struct sctp_hash_cmp_arg *x = arg->key;
808 struct sctp_association *asoc;
811 if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr))
813 if (!sctp_transport_hold(t))
817 if (!net_eq(asoc->base.net, x->net))
820 if (x->ep != asoc->ep)
823 if (x->laddr->v4.sin_port != htons(asoc->base.bind_addr.port))
825 if (!sctp_bind_addr_match(&asoc->base.bind_addr,
826 x->laddr, sctp_sk(asoc->base.sk)))
832 sctp_transport_put(t);
836 static inline u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
838 const struct sctp_transport *t = data;
839 const union sctp_addr *paddr = &t->ipaddr;
840 const struct net *net = t->asoc->base.net;
841 u16 lport = htons(t->asoc->base.bind_addr.port);
844 if (paddr->sa.sa_family == AF_INET6)
845 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
847 addr = paddr->v4.sin_addr.s_addr;
849 return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 |
850 (__force __u32)lport, net_hash_mix(net), seed);
853 static inline u32 sctp_hash_key(const void *data, u32 len, u32 seed)
855 const struct sctp_hash_cmp_arg *x = data;
856 const union sctp_addr *paddr = x->paddr;
857 const struct net *net = x->net;
861 lport = x->ep ? htons(x->ep->base.bind_addr.port) :
862 x->laddr->v4.sin_port;
863 if (paddr->sa.sa_family == AF_INET6)
864 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
866 addr = paddr->v4.sin_addr.s_addr;
868 return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 |
869 (__force __u32)lport, net_hash_mix(net), seed);
872 static const struct rhashtable_params sctp_hash_params = {
873 .head_offset = offsetof(struct sctp_transport, node),
874 .hashfn = sctp_hash_key,
875 .obj_hashfn = sctp_hash_obj,
876 .obj_cmpfn = sctp_hash_cmp,
877 .automatic_shrinking = true,
880 int sctp_transport_hashtable_init(void)
882 return rhashtable_init(&sctp_transport_hashtable, &sctp_hash_params);
885 void sctp_transport_hashtable_destroy(void)
887 rhashtable_destroy(&sctp_transport_hashtable);
890 void sctp_hash_transport(struct sctp_transport *t)
892 struct sctp_hash_cmp_arg arg;
897 arg.ep = t->asoc->ep;
898 arg.paddr = &t->ipaddr;
899 arg.net = sock_net(t->asoc->base.sk);
902 if (rhashtable_lookup_insert_key(&sctp_transport_hashtable, &arg,
903 &t->node, sctp_hash_params) == -EBUSY)
907 void sctp_unhash_transport(struct sctp_transport *t)
912 rhashtable_remove_fast(&sctp_transport_hashtable, &t->node,
916 struct sctp_transport *sctp_addrs_lookup_transport(
918 const union sctp_addr *laddr,
919 const union sctp_addr *paddr)
921 struct sctp_hash_cmp_arg arg = {
928 return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
932 struct sctp_transport *sctp_epaddr_lookup_transport(
933 const struct sctp_endpoint *ep,
934 const union sctp_addr *paddr)
936 struct net *net = sock_net(ep->base.sk);
937 struct sctp_hash_cmp_arg arg = {
943 return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
947 /* Look up an association. */
948 static struct sctp_association *__sctp_lookup_association(
950 const union sctp_addr *local,
951 const union sctp_addr *peer,
952 struct sctp_transport **pt)
954 struct sctp_transport *t;
955 struct sctp_association *asoc = NULL;
957 t = sctp_addrs_lookup_transport(net, local, peer);
958 if (!t || !sctp_transport_hold(t))
968 /* Look up an association. protected by RCU read lock */
970 struct sctp_association *sctp_lookup_association(struct net *net,
971 const union sctp_addr *laddr,
972 const union sctp_addr *paddr,
973 struct sctp_transport **transportp)
975 struct sctp_association *asoc;
978 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
984 /* Is there an association matching the given local and peer addresses? */
985 int sctp_has_association(struct net *net,
986 const union sctp_addr *laddr,
987 const union sctp_addr *paddr)
989 struct sctp_association *asoc;
990 struct sctp_transport *transport;
992 if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) {
993 sctp_transport_put(transport);
1001 * SCTP Implementors Guide, 2.18 Handling of address
1002 * parameters within the INIT or INIT-ACK.
1004 * D) When searching for a matching TCB upon reception of an INIT
1005 * or INIT-ACK chunk the receiver SHOULD use not only the
1006 * source address of the packet (containing the INIT or
1007 * INIT-ACK) but the receiver SHOULD also use all valid
1008 * address parameters contained within the chunk.
1010 * 2.18.3 Solution description
1012 * This new text clearly specifies to an implementor the need
1013 * to look within the INIT or INIT-ACK. Any implementation that
1014 * does not do this, may not be able to establish associations
1015 * in certain circumstances.
1018 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
1019 struct sk_buff *skb,
1020 const union sctp_addr *laddr, struct sctp_transport **transportp)
1022 struct sctp_association *asoc;
1023 union sctp_addr addr;
1024 union sctp_addr *paddr = &addr;
1025 struct sctphdr *sh = sctp_hdr(skb);
1026 union sctp_params params;
1027 sctp_init_chunk_t *init;
1031 * This code will NOT touch anything inside the chunk--it is
1032 * strictly READ-ONLY.
1034 * RFC 2960 3 SCTP packet Format
1036 * Multiple chunks can be bundled into one SCTP packet up to
1037 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
1038 * COMPLETE chunks. These chunks MUST NOT be bundled with any
1039 * other chunk in a packet. See Section 6.10 for more details
1040 * on chunk bundling.
1043 /* Find the start of the TLVs and the end of the chunk. This is
1044 * the region we search for address parameters.
1046 init = (sctp_init_chunk_t *)skb->data;
1048 /* Walk the parameters looking for embedded addresses. */
1049 sctp_walk_params(params, init, init_hdr.params) {
1051 /* Note: Ignoring hostname addresses. */
1052 af = sctp_get_af_specific(param_type2af(params.p->type));
1056 if (!af->from_addr_param(paddr, params.addr, sh->source, 0))
1059 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1067 /* ADD-IP, Section 5.2
1068 * When an endpoint receives an ASCONF Chunk from the remote peer
1069 * special procedures may be needed to identify the association the
1070 * ASCONF Chunk is associated with. To properly find the association
1071 * the following procedures SHOULD be followed:
1073 * D2) If the association is not found, use the address found in the
1074 * Address Parameter TLV combined with the port number found in the
1075 * SCTP common header. If found proceed to rule D4.
1077 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1078 * address found in the ASCONF Address Parameter TLV of each of the
1079 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1081 static struct sctp_association *__sctp_rcv_asconf_lookup(
1083 sctp_chunkhdr_t *ch,
1084 const union sctp_addr *laddr,
1086 struct sctp_transport **transportp)
1088 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
1090 union sctp_addr_param *param;
1091 union sctp_addr paddr;
1093 if (ntohs(ch->length) < sizeof(*asconf) + sizeof(struct sctp_paramhdr))
1096 /* Skip over the ADDIP header and find the Address parameter */
1097 param = (union sctp_addr_param *)(asconf + 1);
1099 af = sctp_get_af_specific(param_type2af(param->p.type));
1103 if (af->from_addr_param(&paddr, param, peer_port, 0))
1106 return __sctp_lookup_association(net, laddr, &paddr, transportp);
1110 /* SCTP-AUTH, Section 6.3:
1111 * If the receiver does not find a STCB for a packet containing an AUTH
1112 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1113 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1116 * This means that any chunks that can help us identify the association need
1117 * to be looked at to find this association.
1119 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
1120 struct sk_buff *skb,
1121 const union sctp_addr *laddr,
1122 struct sctp_transport **transportp)
1124 struct sctp_association *asoc = NULL;
1125 sctp_chunkhdr_t *ch;
1127 unsigned int chunk_num = 1;
1130 /* Walk through the chunks looking for AUTH or ASCONF chunks
1131 * to help us find the association.
1133 ch = (sctp_chunkhdr_t *) skb->data;
1135 /* Break out if chunk length is less then minimal. */
1136 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
1139 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
1140 if (ch_end > skb_tail_pointer(skb))
1145 have_auth = chunk_num;
1148 case SCTP_CID_COOKIE_ECHO:
1149 /* If a packet arrives containing an AUTH chunk as
1150 * a first chunk, a COOKIE-ECHO chunk as the second
1151 * chunk, and possibly more chunks after them, and
1152 * the receiver does not have an STCB for that
1153 * packet, then authentication is based on
1154 * the contents of the COOKIE- ECHO chunk.
1156 if (have_auth == 1 && chunk_num == 2)
1160 case SCTP_CID_ASCONF:
1161 if (have_auth || net->sctp.addip_noauth)
1162 asoc = __sctp_rcv_asconf_lookup(
1164 sctp_hdr(skb)->source,
1173 ch = (sctp_chunkhdr_t *) ch_end;
1175 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb));
1181 * There are circumstances when we need to look inside the SCTP packet
1182 * for information to help us find the association. Examples
1183 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1186 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
1187 struct sk_buff *skb,
1188 const union sctp_addr *laddr,
1189 struct sctp_transport **transportp)
1191 sctp_chunkhdr_t *ch;
1193 /* We do not allow GSO frames here as we need to linearize and
1194 * then cannot guarantee frame boundaries. This shouldn't be an
1195 * issue as packets hitting this are mostly INIT or INIT-ACK and
1196 * those cannot be on GSO-style anyway.
1198 if ((skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) == SKB_GSO_SCTP)
1201 ch = (sctp_chunkhdr_t *) skb->data;
1203 /* The code below will attempt to walk the chunk and extract
1204 * parameter information. Before we do that, we need to verify
1205 * that the chunk length doesn't cause overflow. Otherwise, we'll
1208 if (SCTP_PAD4(ntohs(ch->length)) > skb->len)
1211 /* If this is INIT/INIT-ACK look inside the chunk too. */
1212 if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
1213 return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
1215 return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
1218 /* Lookup an association for an inbound skb. */
1219 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1220 struct sk_buff *skb,
1221 const union sctp_addr *paddr,
1222 const union sctp_addr *laddr,
1223 struct sctp_transport **transportp)
1225 struct sctp_association *asoc;
1227 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1229 /* Further lookup for INIT/INIT-ACK packets.
1230 * SCTP Implementors Guide, 2.18 Handling of address
1231 * parameters within the INIT or INIT-ACK.
1234 asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);