1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2003 International Business Machines, Corp.
6 * Copyright (c) 2001 Intel Corp.
7 * Copyright (c) 2001 Nokia, Inc.
8 * Copyright (c) 2001 La Monte H.P. Yarroll
10 * This file is part of the SCTP kernel implementation
12 * These functions handle all input from the IP layer into SCTP.
14 * Please send any bug reports or fixes you make to the
16 * lksctp developers <linux-sctp@vger.kernel.org>
18 * Written or modified by:
19 * La Monte H.P. Yarroll <piggy@acm.org>
20 * Karl Knutson <karl@athena.chicago.il.us>
21 * Xingang Guo <xingang.guo@intel.com>
22 * Jon Grimm <jgrimm@us.ibm.com>
23 * Hui Huang <hui.huang@nokia.com>
24 * Daisy Chang <daisyc@us.ibm.com>
25 * Sridhar Samudrala <sri@us.ibm.com>
26 * Ardelle Fan <ardelle.fan@intel.com>
29 #include <linux/types.h>
30 #include <linux/list.h> /* For struct list_head */
31 #include <linux/socket.h>
33 #include <linux/time.h> /* For struct timeval */
34 #include <linux/slab.h>
40 #include <net/sctp/sctp.h>
41 #include <net/sctp/sm.h>
42 #include <net/sctp/checksum.h>
43 #include <net/net_namespace.h>
44 #include <linux/rhashtable.h>
45 #include <net/sock_reuseport.h>
47 /* Forward declarations for internal helpers. */
48 static int sctp_rcv_ootb(struct sk_buff *);
49 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
51 const union sctp_addr *paddr,
52 const union sctp_addr *laddr,
53 struct sctp_transport **transportp);
54 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
55 struct net *net, struct sk_buff *skb,
56 const union sctp_addr *laddr,
57 const union sctp_addr *daddr);
58 static struct sctp_association *__sctp_lookup_association(
60 const union sctp_addr *local,
61 const union sctp_addr *peer,
62 struct sctp_transport **pt);
64 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
67 /* Calculate the SCTP checksum of an SCTP packet. */
68 static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb)
70 struct sctphdr *sh = sctp_hdr(skb);
71 __le32 cmp = sh->checksum;
72 __le32 val = sctp_compute_cksum(skb, 0);
75 /* CRC failure, dump it. */
76 __SCTP_INC_STATS(net, SCTP_MIB_CHECKSUMERRORS);
83 * This is the routine which IP calls when receiving an SCTP packet.
85 int sctp_rcv(struct sk_buff *skb)
88 struct sctp_association *asoc;
89 struct sctp_endpoint *ep = NULL;
90 struct sctp_ep_common *rcvr;
91 struct sctp_transport *transport = NULL;
92 struct sctp_chunk *chunk;
97 struct net *net = dev_net(skb->dev);
98 bool is_gso = skb_is_gso(skb) && skb_is_gso_sctp(skb);
100 if (skb->pkt_type != PACKET_HOST)
103 __SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS);
105 /* If packet is too small to contain a single chunk, let's not
106 * waste time on it anymore.
108 if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) +
109 skb_transport_offset(skb))
112 /* If the packet is fragmented and we need to do crc checking,
113 * it's better to just linearize it otherwise crc computing
116 if ((!is_gso && skb_linearize(skb)) ||
117 !pskb_may_pull(skb, sizeof(struct sctphdr)))
120 /* Pull up the IP header. */
121 __skb_pull(skb, skb_transport_offset(skb));
123 skb->csum_valid = 0; /* Previous value not applicable */
124 if (skb_csum_unnecessary(skb))
125 __skb_decr_checksum_unnecessary(skb);
126 else if (!sctp_checksum_disable &&
128 sctp_rcv_checksum(net, skb) < 0)
132 __skb_pull(skb, sizeof(struct sctphdr));
134 family = ipver2af(ip_hdr(skb)->version);
135 af = sctp_get_af_specific(family);
138 SCTP_INPUT_CB(skb)->af = af;
140 /* Initialize local addresses for lookups. */
141 af->from_skb(&src, skb, 1);
142 af->from_skb(&dest, skb, 0);
144 /* If the packet is to or from a non-unicast address,
145 * silently discard the packet.
147 * This is not clearly defined in the RFC except in section
148 * 8.4 - OOTB handling. However, based on the book "Stream Control
149 * Transmission Protocol" 2.1, "It is important to note that the
150 * IP address of an SCTP transport address must be a routable
151 * unicast address. In other words, IP multicast addresses and
152 * IP broadcast addresses cannot be used in an SCTP transport
155 if (!af->addr_valid(&src, NULL, skb) ||
156 !af->addr_valid(&dest, NULL, skb))
159 asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
162 ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src);
164 /* Retrieve the common input handling substructure. */
165 rcvr = asoc ? &asoc->base : &ep->base;
169 * If a frame arrives on an interface and the receiving socket is
170 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
172 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) {
174 sctp_transport_put(transport);
178 sctp_endpoint_put(ep);
181 sk = net->sctp.ctl_sock;
182 ep = sctp_sk(sk)->ep;
183 sctp_endpoint_hold(ep);
188 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
189 * An SCTP packet is called an "out of the blue" (OOTB)
190 * packet if it is correctly formed, i.e., passed the
191 * receiver's checksum check, but the receiver is not
192 * able to identify the association to which this
196 if (sctp_rcv_ootb(skb)) {
197 __SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
198 goto discard_release;
202 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
203 goto discard_release;
206 if (sk_filter(sk, skb))
207 goto discard_release;
209 /* Create an SCTP packet structure. */
210 chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC);
212 goto discard_release;
213 SCTP_INPUT_CB(skb)->chunk = chunk;
215 /* Remember what endpoint is to handle this packet. */
218 /* Remember the SCTP header. */
219 chunk->sctp_hdr = sctp_hdr(skb);
221 /* Set the source and destination addresses of the incoming chunk. */
222 sctp_init_addrs(chunk, &src, &dest);
224 /* Remember where we came from. */
225 chunk->transport = transport;
227 /* Acquire access to the sock lock. Note: We are safe from other
228 * bottom halves on this lock, but a user may be in the lock too,
229 * so check if it is busy.
233 if (sk != rcvr->sk) {
234 /* Our cached sk is different from the rcvr->sk. This is
235 * because migrate()/accept() may have moved the association
236 * to a new socket and released all the sockets. So now we
237 * are holding a lock on the old socket while the user may
238 * be doing something with the new socket. Switch our veiw
246 if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
247 if (sctp_add_backlog(sk, skb)) {
249 sctp_chunk_free(chunk);
250 skb = NULL; /* sctp_chunk_free already freed the skb */
251 goto discard_release;
253 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG);
255 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ);
256 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
261 /* Release the asoc/ep ref we took in the lookup calls. */
263 sctp_transport_put(transport);
265 sctp_endpoint_put(ep);
270 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
275 /* Release the asoc/ep ref we took in the lookup calls. */
277 sctp_transport_put(transport);
279 sctp_endpoint_put(ep);
284 /* Process the backlog queue of the socket. Every skb on
285 * the backlog holds a ref on an association or endpoint.
286 * We hold this ref throughout the state machine to make
287 * sure that the structure we need is still around.
289 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
291 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
292 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
293 struct sctp_transport *t = chunk->transport;
294 struct sctp_ep_common *rcvr = NULL;
299 /* If the rcvr is dead then the association or endpoint
300 * has been deleted and we can safely drop the chunk
301 * and refs that we are holding.
304 sctp_chunk_free(chunk);
308 if (unlikely(rcvr->sk != sk)) {
309 /* In this case, the association moved from one socket to
310 * another. We are currently sitting on the backlog of the
311 * old socket, so we need to move.
312 * However, since we are here in the process context we
313 * need to take make sure that the user doesn't own
314 * the new socket when we process the packet.
315 * If the new socket is user-owned, queue the chunk to the
316 * backlog of the new socket without dropping any refs.
317 * Otherwise, we can safely push the chunk on the inqueue.
324 if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
325 if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
326 sctp_chunk_free(chunk);
330 sctp_inq_push(inqueue, chunk);
335 /* If the chunk was backloged again, don't drop refs */
339 if (!sctp_newsk_ready(sk)) {
340 if (!sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
342 sctp_chunk_free(chunk);
344 sctp_inq_push(inqueue, chunk);
349 /* Release the refs we took in sctp_add_backlog */
350 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
351 sctp_transport_put(t);
352 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
353 sctp_endpoint_put(sctp_ep(rcvr));
360 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
362 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
363 struct sctp_transport *t = chunk->transport;
364 struct sctp_ep_common *rcvr = chunk->rcvr;
367 ret = sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf));
369 /* Hold the assoc/ep while hanging on the backlog queue.
370 * This way, we know structures we need will not disappear
373 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
374 sctp_transport_hold(t);
375 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
376 sctp_endpoint_hold(sctp_ep(rcvr));
384 /* Handle icmp frag needed error. */
385 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
386 struct sctp_transport *t, __u32 pmtu)
389 (t->pathmtu <= pmtu &&
390 t->pl.probe_size + sctp_transport_pl_hlen(t) <= pmtu))
393 if (sock_owned_by_user(sk)) {
394 atomic_set(&t->mtu_info, pmtu);
395 asoc->pmtu_pending = 1;
400 if (!(t->param_flags & SPP_PMTUD_ENABLE))
401 /* We can't allow retransmitting in such case, as the
402 * retransmission would be sized just as before, and thus we
403 * would get another icmp, and retransmit again.
407 /* Update transports view of the MTU. Return if no update was needed.
408 * If an update wasn't needed/possible, it also doesn't make sense to
409 * try to retransmit now.
411 if (!sctp_transport_update_pmtu(t, pmtu))
414 /* Update association pmtu. */
415 sctp_assoc_sync_pmtu(asoc);
417 /* Retransmit with the new pmtu setting. */
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)
553 __releases(&((__sk)->sk_lock.slock))
556 sctp_transport_put(t);
559 static void sctp_v4_err_handle(struct sctp_transport *t, struct sk_buff *skb,
560 __u8 type, __u8 code, __u32 info)
562 struct sctp_association *asoc = t->asoc;
563 struct sock *sk = asoc->base.sk;
567 case ICMP_PARAMETERPROB:
570 case ICMP_DEST_UNREACH:
571 if (code > NR_ICMP_UNREACH)
573 if (code == ICMP_FRAG_NEEDED) {
574 sctp_icmp_frag_needed(sk, asoc, t, SCTP_TRUNC4(info));
577 if (code == ICMP_PROT_UNREACH) {
578 sctp_icmp_proto_unreachable(sk, asoc, t);
581 err = icmp_err_convert[code].errno;
583 case ICMP_TIME_EXCEEDED:
584 if (code == ICMP_EXC_FRAGTIME)
590 sctp_icmp_redirect(sk, t, skb);
594 if (!sock_owned_by_user(sk) && inet_sk(sk)->recverr) {
596 sk->sk_error_report(sk);
597 } else { /* Only an error on timeout */
598 sk->sk_err_soft = err;
603 * This routine is called by the ICMP module when it gets some
604 * sort of error condition. If err < 0 then the socket should
605 * be closed and the error returned to the user. If err > 0
606 * it's just the icmp type << 8 | icmp code. After adjustment
607 * header points to the first 8 bytes of the sctp header. We need
608 * to find the appropriate port.
610 * The locking strategy used here is very "optimistic". When
611 * someone else accesses the socket the ICMP is just dropped
612 * and for some paths there is no check at all.
613 * A more general error queue to queue errors for later handling
614 * is probably better.
617 int sctp_v4_err(struct sk_buff *skb, __u32 info)
619 const struct iphdr *iph = (const struct iphdr *)skb->data;
620 const int type = icmp_hdr(skb)->type;
621 const int code = icmp_hdr(skb)->code;
622 struct net *net = dev_net(skb->dev);
623 struct sctp_transport *transport;
624 struct sctp_association *asoc;
625 __u16 saveip, savesctp;
628 /* Fix up skb to look at the embedded net header. */
629 saveip = skb->network_header;
630 savesctp = skb->transport_header;
631 skb_reset_network_header(skb);
632 skb_set_transport_header(skb, iph->ihl * 4);
633 sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
634 /* Put back, the original values. */
635 skb->network_header = saveip;
636 skb->transport_header = savesctp;
638 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
642 sctp_v4_err_handle(transport, skb, type, code, info);
643 sctp_err_finish(sk, transport);
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)
662 struct sctp_chunkhdr *ch, _ch;
663 int ch_end, offset = 0;
665 /* Scan through all the chunks in the packet. */
667 /* Make sure we have at least the header there */
668 if (offset + sizeof(_ch) > skb->len)
671 ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch);
673 /* Break out if chunk length is less then minimal. */
674 if (ntohs(ch->length) < sizeof(_ch))
677 ch_end = offset + SCTP_PAD4(ntohs(ch->length));
678 if (ch_end > skb->len)
681 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
682 * receiver MUST silently discard the OOTB packet and take no
685 if (SCTP_CID_ABORT == ch->type)
688 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
689 * chunk, the receiver should silently discard the packet
690 * and take no further action.
692 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
696 * This will discard packets with INIT chunk bundled as
697 * subsequent chunks in the packet. When INIT is first,
698 * the normal INIT processing will discard the chunk.
700 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
704 } while (ch_end < skb->len);
712 /* Insert endpoint into the hash table. */
713 static int __sctp_hash_endpoint(struct sctp_endpoint *ep)
715 struct sock *sk = ep->base.sk;
716 struct net *net = sock_net(sk);
717 struct sctp_hashbucket *head;
718 struct sctp_ep_common *epb;
721 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
722 head = &sctp_ep_hashtable[epb->hashent];
724 if (sk->sk_reuseport) {
725 bool any = sctp_is_ep_boundall(sk);
726 struct sctp_ep_common *epb2;
727 struct list_head *list;
728 int cnt = 0, err = 1;
730 list_for_each(list, &ep->base.bind_addr.address_list)
733 sctp_for_each_hentry(epb2, &head->chain) {
734 struct sock *sk2 = epb2->sk;
736 if (!net_eq(sock_net(sk2), net) || sk2 == sk ||
737 !uid_eq(sock_i_uid(sk2), sock_i_uid(sk)) ||
741 err = sctp_bind_addrs_check(sctp_sk(sk2),
744 err = reuseport_add_sock(sk, sk2, any);
748 } else if (err < 0) {
754 err = reuseport_alloc(sk, any);
760 write_lock(&head->lock);
761 hlist_add_head(&epb->node, &head->chain);
762 write_unlock(&head->lock);
766 /* Add an endpoint to the hash. Local BH-safe. */
767 int sctp_hash_endpoint(struct sctp_endpoint *ep)
772 err = __sctp_hash_endpoint(ep);
778 /* Remove endpoint from the hash table. */
779 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
781 struct sock *sk = ep->base.sk;
782 struct sctp_hashbucket *head;
783 struct sctp_ep_common *epb;
787 epb->hashent = sctp_ep_hashfn(sock_net(sk), epb->bind_addr.port);
789 head = &sctp_ep_hashtable[epb->hashent];
791 if (rcu_access_pointer(sk->sk_reuseport_cb))
792 reuseport_detach_sock(sk);
794 write_lock(&head->lock);
795 hlist_del_init(&epb->node);
796 write_unlock(&head->lock);
799 /* Remove endpoint from the hash. Local BH-safe. */
800 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
803 __sctp_unhash_endpoint(ep);
807 static inline __u32 sctp_hashfn(const struct net *net, __be16 lport,
808 const union sctp_addr *paddr, __u32 seed)
812 if (paddr->sa.sa_family == AF_INET6)
813 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
815 addr = (__force __u32)paddr->v4.sin_addr.s_addr;
817 return jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
818 (__force __u32)lport, net_hash_mix(net), seed);
821 /* Look up an endpoint. */
822 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
823 struct net *net, struct sk_buff *skb,
824 const union sctp_addr *laddr,
825 const union sctp_addr *paddr)
827 struct sctp_hashbucket *head;
828 struct sctp_ep_common *epb;
829 struct sctp_endpoint *ep;
834 lport = laddr->v4.sin_port;
835 hash = sctp_ep_hashfn(net, ntohs(lport));
836 head = &sctp_ep_hashtable[hash];
837 read_lock(&head->lock);
838 sctp_for_each_hentry(epb, &head->chain) {
840 if (sctp_endpoint_is_match(ep, net, laddr))
844 ep = sctp_sk(net->sctp.ctl_sock)->ep;
848 if (sk->sk_reuseport) {
849 __u32 phash = sctp_hashfn(net, lport, paddr, 0);
851 sk = reuseport_select_sock(sk, phash, skb,
852 sizeof(struct sctphdr));
854 ep = sctp_sk(sk)->ep;
856 sctp_endpoint_hold(ep);
857 read_unlock(&head->lock);
861 /* rhashtable for transport */
862 struct sctp_hash_cmp_arg {
863 const union sctp_addr *paddr;
864 const struct net *net;
868 static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
871 struct sctp_transport *t = (struct sctp_transport *)ptr;
872 const struct sctp_hash_cmp_arg *x = arg->key;
875 if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr))
877 if (!sctp_transport_hold(t))
880 if (!net_eq(t->asoc->base.net, x->net))
882 if (x->lport != htons(t->asoc->base.bind_addr.port))
887 sctp_transport_put(t);
891 static inline __u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
893 const struct sctp_transport *t = data;
895 return sctp_hashfn(t->asoc->base.net,
896 htons(t->asoc->base.bind_addr.port),
900 static inline __u32 sctp_hash_key(const void *data, u32 len, u32 seed)
902 const struct sctp_hash_cmp_arg *x = data;
904 return sctp_hashfn(x->net, x->lport, x->paddr, seed);
907 static const struct rhashtable_params sctp_hash_params = {
908 .head_offset = offsetof(struct sctp_transport, node),
909 .hashfn = sctp_hash_key,
910 .obj_hashfn = sctp_hash_obj,
911 .obj_cmpfn = sctp_hash_cmp,
912 .automatic_shrinking = true,
915 int sctp_transport_hashtable_init(void)
917 return rhltable_init(&sctp_transport_hashtable, &sctp_hash_params);
920 void sctp_transport_hashtable_destroy(void)
922 rhltable_destroy(&sctp_transport_hashtable);
925 int sctp_hash_transport(struct sctp_transport *t)
927 struct sctp_transport *transport;
928 struct rhlist_head *tmp, *list;
929 struct sctp_hash_cmp_arg arg;
935 arg.net = t->asoc->base.net;
936 arg.paddr = &t->ipaddr;
937 arg.lport = htons(t->asoc->base.bind_addr.port);
940 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
943 rhl_for_each_entry_rcu(transport, tmp, list, node)
944 if (transport->asoc->ep == t->asoc->ep) {
950 err = rhltable_insert_key(&sctp_transport_hashtable, &arg,
951 &t->node, sctp_hash_params);
953 pr_err_once("insert transport fail, errno %d\n", err);
958 void sctp_unhash_transport(struct sctp_transport *t)
963 rhltable_remove(&sctp_transport_hashtable, &t->node,
967 /* return a transport with holding it */
968 struct sctp_transport *sctp_addrs_lookup_transport(
970 const union sctp_addr *laddr,
971 const union sctp_addr *paddr)
973 struct rhlist_head *tmp, *list;
974 struct sctp_transport *t;
975 struct sctp_hash_cmp_arg arg = {
978 .lport = laddr->v4.sin_port,
981 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
984 rhl_for_each_entry_rcu(t, tmp, list, node) {
985 if (!sctp_transport_hold(t))
988 if (sctp_bind_addr_match(&t->asoc->base.bind_addr,
989 laddr, sctp_sk(t->asoc->base.sk)))
991 sctp_transport_put(t);
997 /* return a transport without holding it, as it's only used under sock lock */
998 struct sctp_transport *sctp_epaddr_lookup_transport(
999 const struct sctp_endpoint *ep,
1000 const union sctp_addr *paddr)
1002 struct rhlist_head *tmp, *list;
1003 struct sctp_transport *t;
1004 struct sctp_hash_cmp_arg arg = {
1006 .net = ep->base.net,
1007 .lport = htons(ep->base.bind_addr.port),
1010 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
1013 rhl_for_each_entry_rcu(t, tmp, list, node)
1014 if (ep == t->asoc->ep)
1020 /* Look up an association. */
1021 static struct sctp_association *__sctp_lookup_association(
1023 const union sctp_addr *local,
1024 const union sctp_addr *peer,
1025 struct sctp_transport **pt)
1027 struct sctp_transport *t;
1028 struct sctp_association *asoc = NULL;
1030 t = sctp_addrs_lookup_transport(net, local, peer);
1041 /* Look up an association. protected by RCU read lock */
1043 struct sctp_association *sctp_lookup_association(struct net *net,
1044 const union sctp_addr *laddr,
1045 const union sctp_addr *paddr,
1046 struct sctp_transport **transportp)
1048 struct sctp_association *asoc;
1051 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1057 /* Is there an association matching the given local and peer addresses? */
1058 bool sctp_has_association(struct net *net,
1059 const union sctp_addr *laddr,
1060 const union sctp_addr *paddr)
1062 struct sctp_transport *transport;
1064 if (sctp_lookup_association(net, laddr, paddr, &transport)) {
1065 sctp_transport_put(transport);
1073 * SCTP Implementors Guide, 2.18 Handling of address
1074 * parameters within the INIT or INIT-ACK.
1076 * D) When searching for a matching TCB upon reception of an INIT
1077 * or INIT-ACK chunk the receiver SHOULD use not only the
1078 * source address of the packet (containing the INIT or
1079 * INIT-ACK) but the receiver SHOULD also use all valid
1080 * address parameters contained within the chunk.
1082 * 2.18.3 Solution description
1084 * This new text clearly specifies to an implementor the need
1085 * to look within the INIT or INIT-ACK. Any implementation that
1086 * does not do this, may not be able to establish associations
1087 * in certain circumstances.
1090 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
1091 struct sk_buff *skb,
1092 const union sctp_addr *laddr, struct sctp_transport **transportp)
1094 struct sctp_association *asoc;
1095 union sctp_addr addr;
1096 union sctp_addr *paddr = &addr;
1097 struct sctphdr *sh = sctp_hdr(skb);
1098 union sctp_params params;
1099 struct sctp_init_chunk *init;
1103 * This code will NOT touch anything inside the chunk--it is
1104 * strictly READ-ONLY.
1106 * RFC 2960 3 SCTP packet Format
1108 * Multiple chunks can be bundled into one SCTP packet up to
1109 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
1110 * COMPLETE chunks. These chunks MUST NOT be bundled with any
1111 * other chunk in a packet. See Section 6.10 for more details
1112 * on chunk bundling.
1115 /* Find the start of the TLVs and the end of the chunk. This is
1116 * the region we search for address parameters.
1118 init = (struct sctp_init_chunk *)skb->data;
1120 /* Walk the parameters looking for embedded addresses. */
1121 sctp_walk_params(params, init, init_hdr.params) {
1123 /* Note: Ignoring hostname addresses. */
1124 af = sctp_get_af_specific(param_type2af(params.p->type));
1128 af->from_addr_param(paddr, params.addr, sh->source, 0);
1130 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1138 /* ADD-IP, Section 5.2
1139 * When an endpoint receives an ASCONF Chunk from the remote peer
1140 * special procedures may be needed to identify the association the
1141 * ASCONF Chunk is associated with. To properly find the association
1142 * the following procedures SHOULD be followed:
1144 * D2) If the association is not found, use the address found in the
1145 * Address Parameter TLV combined with the port number found in the
1146 * SCTP common header. If found proceed to rule D4.
1148 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1149 * address found in the ASCONF Address Parameter TLV of each of the
1150 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1152 static struct sctp_association *__sctp_rcv_asconf_lookup(
1154 struct sctp_chunkhdr *ch,
1155 const union sctp_addr *laddr,
1157 struct sctp_transport **transportp)
1159 struct sctp_addip_chunk *asconf = (struct sctp_addip_chunk *)ch;
1161 union sctp_addr_param *param;
1162 union sctp_addr paddr;
1164 /* Skip over the ADDIP header and find the Address parameter */
1165 param = (union sctp_addr_param *)(asconf + 1);
1167 af = sctp_get_af_specific(param_type2af(param->p.type));
1171 af->from_addr_param(&paddr, param, peer_port, 0);
1173 return __sctp_lookup_association(net, laddr, &paddr, transportp);
1177 /* SCTP-AUTH, Section 6.3:
1178 * If the receiver does not find a STCB for a packet containing an AUTH
1179 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1180 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1183 * This means that any chunks that can help us identify the association need
1184 * to be looked at to find this association.
1186 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
1187 struct sk_buff *skb,
1188 const union sctp_addr *laddr,
1189 struct sctp_transport **transportp)
1191 struct sctp_association *asoc = NULL;
1192 struct sctp_chunkhdr *ch;
1194 unsigned int chunk_num = 1;
1197 /* Walk through the chunks looking for AUTH or ASCONF chunks
1198 * to help us find the association.
1200 ch = (struct sctp_chunkhdr *)skb->data;
1202 /* Break out if chunk length is less then minimal. */
1203 if (ntohs(ch->length) < sizeof(*ch))
1206 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
1207 if (ch_end > skb_tail_pointer(skb))
1212 have_auth = chunk_num;
1215 case SCTP_CID_COOKIE_ECHO:
1216 /* If a packet arrives containing an AUTH chunk as
1217 * a first chunk, a COOKIE-ECHO chunk as the second
1218 * chunk, and possibly more chunks after them, and
1219 * the receiver does not have an STCB for that
1220 * packet, then authentication is based on
1221 * the contents of the COOKIE- ECHO chunk.
1223 if (have_auth == 1 && chunk_num == 2)
1227 case SCTP_CID_ASCONF:
1228 if (have_auth || net->sctp.addip_noauth)
1229 asoc = __sctp_rcv_asconf_lookup(
1231 sctp_hdr(skb)->source,
1240 ch = (struct sctp_chunkhdr *)ch_end;
1242 } while (ch_end < skb_tail_pointer(skb));
1248 * There are circumstances when we need to look inside the SCTP packet
1249 * for information to help us find the association. Examples
1250 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1253 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
1254 struct sk_buff *skb,
1255 const union sctp_addr *laddr,
1256 struct sctp_transport **transportp)
1258 struct sctp_chunkhdr *ch;
1260 /* We do not allow GSO frames here as we need to linearize and
1261 * then cannot guarantee frame boundaries. This shouldn't be an
1262 * issue as packets hitting this are mostly INIT or INIT-ACK and
1263 * those cannot be on GSO-style anyway.
1265 if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
1268 ch = (struct sctp_chunkhdr *)skb->data;
1270 /* The code below will attempt to walk the chunk and extract
1271 * parameter information. Before we do that, we need to verify
1272 * that the chunk length doesn't cause overflow. Otherwise, we'll
1275 if (SCTP_PAD4(ntohs(ch->length)) > skb->len)
1278 /* If this is INIT/INIT-ACK look inside the chunk too. */
1279 if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
1280 return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
1282 return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
1285 /* Lookup an association for an inbound skb. */
1286 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1287 struct sk_buff *skb,
1288 const union sctp_addr *paddr,
1289 const union sctp_addr *laddr,
1290 struct sctp_transport **transportp)
1292 struct sctp_association *asoc;
1294 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1298 /* Further lookup for INIT/INIT-ACK packets.
1299 * SCTP Implementors Guide, 2.18 Handling of address
1300 * parameters within the INIT or INIT-ACK.
1302 asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);
1306 if (paddr->sa.sa_family == AF_INET)
1307 pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n",
1308 &laddr->v4.sin_addr, ntohs(laddr->v4.sin_port),
1309 &paddr->v4.sin_addr, ntohs(paddr->v4.sin_port));
1311 pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n",
1312 &laddr->v6.sin6_addr, ntohs(laddr->v6.sin6_port),
1313 &paddr->v6.sin6_addr, ntohs(paddr->v6.sin6_port));