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 /* We can't allow retransmitting in such case, as the
406 * retransmission would be sized just as before, and thus we
407 * would get another icmp, and retransmit again.
411 /* Update transports view of the MTU. Return if no update was needed.
412 * If an update wasn't needed/possible, it also doesn't make sense to
413 * try to retransmit now.
415 if (!sctp_transport_update_pmtu(t, pmtu))
418 /* Update association pmtu. */
419 sctp_assoc_sync_pmtu(asoc);
421 /* Retransmit with the new pmtu setting. */
422 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
425 void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
428 struct dst_entry *dst;
430 if (sock_owned_by_user(sk) || !t)
432 dst = sctp_transport_dst_check(t);
434 dst->ops->redirect(dst, sk, skb);
438 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
440 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
441 * or a "Protocol Unreachable" treat this message as an abort
442 * with the T bit set.
444 * This function sends an event to the state machine, which will abort the
448 void sctp_icmp_proto_unreachable(struct sock *sk,
449 struct sctp_association *asoc,
450 struct sctp_transport *t)
452 if (sock_owned_by_user(sk)) {
453 if (timer_pending(&t->proto_unreach_timer))
456 if (!mod_timer(&t->proto_unreach_timer,
458 sctp_transport_hold(t);
461 struct net *net = sock_net(sk);
463 pr_debug("%s: unrecognized next header type "
464 "encountered!\n", __func__);
466 if (del_timer(&t->proto_unreach_timer))
467 sctp_transport_put(t);
469 sctp_do_sm(net, SCTP_EVENT_T_OTHER,
470 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
471 asoc->state, asoc->ep, asoc, t,
476 /* Common lookup code for icmp/icmpv6 error handler. */
477 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
478 struct sctphdr *sctphdr,
479 struct sctp_association **app,
480 struct sctp_transport **tpp)
482 struct sctp_init_chunk *chunkhdr, _chunkhdr;
483 union sctp_addr saddr;
484 union sctp_addr daddr;
486 struct sock *sk = NULL;
487 struct sctp_association *asoc;
488 struct sctp_transport *transport = NULL;
489 __u32 vtag = ntohl(sctphdr->vtag);
491 *app = NULL; *tpp = NULL;
493 af = sctp_get_af_specific(family);
498 /* Initialize local addresses for lookups. */
499 af->from_skb(&saddr, skb, 1);
500 af->from_skb(&daddr, skb, 0);
502 /* Look for an association that matches the incoming ICMP error
505 asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport);
511 /* RFC 4960, Appendix C. ICMP Handling
513 * ICMP6) An implementation MUST validate that the Verification Tag
514 * contained in the ICMP message matches the Verification Tag of
515 * the peer. If the Verification Tag is not 0 and does NOT
516 * match, discard the ICMP message. If it is 0 and the ICMP
517 * message contains enough bytes to verify that the chunk type is
518 * an INIT chunk and that the Initiate Tag matches the tag of the
519 * peer, continue with ICMP7. If the ICMP message is too short
520 * or the chunk type or the Initiate Tag does not match, silently
521 * discard the packet.
524 /* chunk header + first 4 octects of init header */
525 chunkhdr = skb_header_pointer(skb, skb_transport_offset(skb) +
526 sizeof(struct sctphdr),
527 sizeof(struct sctp_chunkhdr) +
528 sizeof(__be32), &_chunkhdr);
530 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
531 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag)
534 } else if (vtag != asoc->c.peer_vtag) {
540 /* If too many ICMPs get dropped on busy
541 * servers this needs to be solved differently.
543 if (sock_owned_by_user(sk))
544 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
551 sctp_transport_put(transport);
555 /* Common cleanup code for icmp/icmpv6 error handler. */
556 void sctp_err_finish(struct sock *sk, struct sctp_transport *t)
559 sctp_transport_put(t);
563 * This routine is called by the ICMP module when it gets some
564 * sort of error condition. If err < 0 then the socket should
565 * be closed and the error returned to the user. If err > 0
566 * it's just the icmp type << 8 | icmp code. After adjustment
567 * header points to the first 8 bytes of the sctp header. We need
568 * to find the appropriate port.
570 * The locking strategy used here is very "optimistic". When
571 * someone else accesses the socket the ICMP is just dropped
572 * and for some paths there is no check at all.
573 * A more general error queue to queue errors for later handling
574 * is probably better.
577 void sctp_v4_err(struct sk_buff *skb, __u32 info)
579 const struct iphdr *iph = (const struct iphdr *)skb->data;
580 const int ihlen = iph->ihl * 4;
581 const int type = icmp_hdr(skb)->type;
582 const int code = icmp_hdr(skb)->code;
584 struct sctp_association *asoc = NULL;
585 struct sctp_transport *transport;
586 struct inet_sock *inet;
587 __u16 saveip, savesctp;
589 struct net *net = dev_net(skb->dev);
591 /* Fix up skb to look at the embedded net header. */
592 saveip = skb->network_header;
593 savesctp = skb->transport_header;
594 skb_reset_network_header(skb);
595 skb_set_transport_header(skb, ihlen);
596 sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
597 /* Put back, the original values. */
598 skb->network_header = saveip;
599 skb->transport_header = savesctp;
601 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
604 /* Warning: The sock lock is held. Remember to call
609 case ICMP_PARAMETERPROB:
612 case ICMP_DEST_UNREACH:
613 if (code > NR_ICMP_UNREACH)
616 /* PMTU discovery (RFC1191) */
617 if (ICMP_FRAG_NEEDED == code) {
618 sctp_icmp_frag_needed(sk, asoc, transport,
622 if (ICMP_PROT_UNREACH == code) {
623 sctp_icmp_proto_unreachable(sk, asoc,
628 err = icmp_err_convert[code].errno;
630 case ICMP_TIME_EXCEEDED:
631 /* Ignore any time exceeded errors due to fragment reassembly
634 if (ICMP_EXC_FRAGTIME == code)
640 sctp_icmp_redirect(sk, transport, skb);
641 /* Fall through to out_unlock. */
647 if (!sock_owned_by_user(sk) && inet->recverr) {
649 sk->sk_error_report(sk);
650 } else { /* Only an error on timeout */
651 sk->sk_err_soft = err;
655 sctp_err_finish(sk, transport);
659 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
661 * This function scans all the chunks in the OOTB packet to determine if
662 * the packet should be discarded right away. If a response might be needed
663 * for this packet, or, if further processing is possible, the packet will
664 * be queued to a proper inqueue for the next phase of handling.
667 * Return 0 - If further processing is needed.
668 * Return 1 - If the packet can be discarded right away.
670 static int sctp_rcv_ootb(struct sk_buff *skb)
672 struct sctp_chunkhdr *ch, _ch;
673 int ch_end, offset = 0;
675 /* Scan through all the chunks in the packet. */
677 /* Make sure we have at least the header there */
678 if (offset + sizeof(_ch) > skb->len)
681 ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch);
683 /* Break out if chunk length is less then minimal. */
684 if (!ch || ntohs(ch->length) < sizeof(_ch))
687 ch_end = offset + SCTP_PAD4(ntohs(ch->length));
688 if (ch_end > skb->len)
691 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
692 * receiver MUST silently discard the OOTB packet and take no
695 if (SCTP_CID_ABORT == ch->type)
698 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
699 * chunk, the receiver should silently discard the packet
700 * and take no further action.
702 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
706 * This will discard packets with INIT chunk bundled as
707 * subsequent chunks in the packet. When INIT is first,
708 * the normal INIT processing will discard the chunk.
710 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
714 } while (ch_end < skb->len);
722 /* Insert endpoint into the hash table. */
723 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
725 struct net *net = sock_net(ep->base.sk);
726 struct sctp_ep_common *epb;
727 struct sctp_hashbucket *head;
731 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
732 head = &sctp_ep_hashtable[epb->hashent];
734 write_lock(&head->lock);
735 hlist_add_head(&epb->node, &head->chain);
736 write_unlock(&head->lock);
739 /* Add an endpoint to the hash. Local BH-safe. */
740 void sctp_hash_endpoint(struct sctp_endpoint *ep)
743 __sctp_hash_endpoint(ep);
747 /* Remove endpoint from the hash table. */
748 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
750 struct net *net = sock_net(ep->base.sk);
751 struct sctp_hashbucket *head;
752 struct sctp_ep_common *epb;
756 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
758 head = &sctp_ep_hashtable[epb->hashent];
760 write_lock(&head->lock);
761 hlist_del_init(&epb->node);
762 write_unlock(&head->lock);
765 /* Remove endpoint from the hash. Local BH-safe. */
766 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
769 __sctp_unhash_endpoint(ep);
773 /* Look up an endpoint. */
774 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
775 const union sctp_addr *laddr)
777 struct sctp_hashbucket *head;
778 struct sctp_ep_common *epb;
779 struct sctp_endpoint *ep;
782 hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
783 head = &sctp_ep_hashtable[hash];
784 read_lock(&head->lock);
785 sctp_for_each_hentry(epb, &head->chain) {
787 if (sctp_endpoint_is_match(ep, net, laddr))
791 ep = sctp_sk(net->sctp.ctl_sock)->ep;
794 sctp_endpoint_hold(ep);
795 read_unlock(&head->lock);
799 /* rhashtable for transport */
800 struct sctp_hash_cmp_arg {
801 const union sctp_addr *paddr;
802 const struct net *net;
806 static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
809 struct sctp_transport *t = (struct sctp_transport *)ptr;
810 const struct sctp_hash_cmp_arg *x = arg->key;
813 if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr))
815 if (!sctp_transport_hold(t))
818 if (!net_eq(t->asoc->base.net, x->net))
820 if (x->lport != htons(t->asoc->base.bind_addr.port))
825 sctp_transport_put(t);
829 static inline __u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
831 const struct sctp_transport *t = data;
832 const union sctp_addr *paddr = &t->ipaddr;
833 const struct net *net = t->asoc->base.net;
834 __be16 lport = htons(t->asoc->base.bind_addr.port);
837 if (paddr->sa.sa_family == AF_INET6)
838 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
840 addr = (__force __u32)paddr->v4.sin_addr.s_addr;
842 return jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
843 (__force __u32)lport, net_hash_mix(net), seed);
846 static inline __u32 sctp_hash_key(const void *data, u32 len, u32 seed)
848 const struct sctp_hash_cmp_arg *x = data;
849 const union sctp_addr *paddr = x->paddr;
850 const struct net *net = x->net;
851 __be16 lport = x->lport;
854 if (paddr->sa.sa_family == AF_INET6)
855 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
857 addr = (__force __u32)paddr->v4.sin_addr.s_addr;
859 return jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
860 (__force __u32)lport, net_hash_mix(net), seed);
863 static const struct rhashtable_params sctp_hash_params = {
864 .head_offset = offsetof(struct sctp_transport, node),
865 .hashfn = sctp_hash_key,
866 .obj_hashfn = sctp_hash_obj,
867 .obj_cmpfn = sctp_hash_cmp,
868 .automatic_shrinking = true,
871 int sctp_transport_hashtable_init(void)
873 return rhltable_init(&sctp_transport_hashtable, &sctp_hash_params);
876 void sctp_transport_hashtable_destroy(void)
878 rhltable_destroy(&sctp_transport_hashtable);
881 int sctp_hash_transport(struct sctp_transport *t)
883 struct sctp_transport *transport;
884 struct rhlist_head *tmp, *list;
885 struct sctp_hash_cmp_arg arg;
891 arg.net = sock_net(t->asoc->base.sk);
892 arg.paddr = &t->ipaddr;
893 arg.lport = htons(t->asoc->base.bind_addr.port);
896 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
899 rhl_for_each_entry_rcu(transport, tmp, list, node)
900 if (transport->asoc->ep == t->asoc->ep) {
906 err = rhltable_insert_key(&sctp_transport_hashtable, &arg,
907 &t->node, sctp_hash_params);
909 pr_err_once("insert transport fail, errno %d\n", err);
914 void sctp_unhash_transport(struct sctp_transport *t)
919 rhltable_remove(&sctp_transport_hashtable, &t->node,
923 /* return a transport with holding it */
924 struct sctp_transport *sctp_addrs_lookup_transport(
926 const union sctp_addr *laddr,
927 const union sctp_addr *paddr)
929 struct rhlist_head *tmp, *list;
930 struct sctp_transport *t;
931 struct sctp_hash_cmp_arg arg = {
934 .lport = laddr->v4.sin_port,
937 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
940 rhl_for_each_entry_rcu(t, tmp, list, node) {
941 if (!sctp_transport_hold(t))
944 if (sctp_bind_addr_match(&t->asoc->base.bind_addr,
945 laddr, sctp_sk(t->asoc->base.sk)))
947 sctp_transport_put(t);
953 /* return a transport without holding it, as it's only used under sock lock */
954 struct sctp_transport *sctp_epaddr_lookup_transport(
955 const struct sctp_endpoint *ep,
956 const union sctp_addr *paddr)
958 struct net *net = sock_net(ep->base.sk);
959 struct rhlist_head *tmp, *list;
960 struct sctp_transport *t;
961 struct sctp_hash_cmp_arg arg = {
964 .lport = htons(ep->base.bind_addr.port),
967 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
970 rhl_for_each_entry_rcu(t, tmp, list, node)
971 if (ep == t->asoc->ep)
977 /* Look up an association. */
978 static struct sctp_association *__sctp_lookup_association(
980 const union sctp_addr *local,
981 const union sctp_addr *peer,
982 struct sctp_transport **pt)
984 struct sctp_transport *t;
985 struct sctp_association *asoc = NULL;
987 t = sctp_addrs_lookup_transport(net, local, peer);
998 /* Look up an association. protected by RCU read lock */
1000 struct sctp_association *sctp_lookup_association(struct net *net,
1001 const union sctp_addr *laddr,
1002 const union sctp_addr *paddr,
1003 struct sctp_transport **transportp)
1005 struct sctp_association *asoc;
1008 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1014 /* Is there an association matching the given local and peer addresses? */
1015 int sctp_has_association(struct net *net,
1016 const union sctp_addr *laddr,
1017 const union sctp_addr *paddr)
1019 struct sctp_association *asoc;
1020 struct sctp_transport *transport;
1022 if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) {
1023 sctp_transport_put(transport);
1031 * SCTP Implementors Guide, 2.18 Handling of address
1032 * parameters within the INIT or INIT-ACK.
1034 * D) When searching for a matching TCB upon reception of an INIT
1035 * or INIT-ACK chunk the receiver SHOULD use not only the
1036 * source address of the packet (containing the INIT or
1037 * INIT-ACK) but the receiver SHOULD also use all valid
1038 * address parameters contained within the chunk.
1040 * 2.18.3 Solution description
1042 * This new text clearly specifies to an implementor the need
1043 * to look within the INIT or INIT-ACK. Any implementation that
1044 * does not do this, may not be able to establish associations
1045 * in certain circumstances.
1048 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
1049 struct sk_buff *skb,
1050 const union sctp_addr *laddr, struct sctp_transport **transportp)
1052 struct sctp_association *asoc;
1053 union sctp_addr addr;
1054 union sctp_addr *paddr = &addr;
1055 struct sctphdr *sh = sctp_hdr(skb);
1056 union sctp_params params;
1057 struct sctp_init_chunk *init;
1061 * This code will NOT touch anything inside the chunk--it is
1062 * strictly READ-ONLY.
1064 * RFC 2960 3 SCTP packet Format
1066 * Multiple chunks can be bundled into one SCTP packet up to
1067 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
1068 * COMPLETE chunks. These chunks MUST NOT be bundled with any
1069 * other chunk in a packet. See Section 6.10 for more details
1070 * on chunk bundling.
1073 /* Find the start of the TLVs and the end of the chunk. This is
1074 * the region we search for address parameters.
1076 init = (struct sctp_init_chunk *)skb->data;
1078 /* Walk the parameters looking for embedded addresses. */
1079 sctp_walk_params(params, init, init_hdr.params) {
1081 /* Note: Ignoring hostname addresses. */
1082 af = sctp_get_af_specific(param_type2af(params.p->type));
1086 if (!af->from_addr_param(paddr, params.addr, sh->source, 0))
1089 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1097 /* ADD-IP, Section 5.2
1098 * When an endpoint receives an ASCONF Chunk from the remote peer
1099 * special procedures may be needed to identify the association the
1100 * ASCONF Chunk is associated with. To properly find the association
1101 * the following procedures SHOULD be followed:
1103 * D2) If the association is not found, use the address found in the
1104 * Address Parameter TLV combined with the port number found in the
1105 * SCTP common header. If found proceed to rule D4.
1107 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1108 * address found in the ASCONF Address Parameter TLV of each of the
1109 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1111 static struct sctp_association *__sctp_rcv_asconf_lookup(
1113 struct sctp_chunkhdr *ch,
1114 const union sctp_addr *laddr,
1116 struct sctp_transport **transportp)
1118 struct sctp_addip_chunk *asconf = (struct sctp_addip_chunk *)ch;
1120 union sctp_addr_param *param;
1121 union sctp_addr paddr;
1123 if (ntohs(ch->length) < sizeof(*asconf) + sizeof(struct sctp_paramhdr))
1126 /* Skip over the ADDIP header and find the Address parameter */
1127 param = (union sctp_addr_param *)(asconf + 1);
1129 af = sctp_get_af_specific(param_type2af(param->p.type));
1133 if (!af->from_addr_param(&paddr, param, peer_port, 0))
1136 return __sctp_lookup_association(net, laddr, &paddr, transportp);
1140 /* SCTP-AUTH, Section 6.3:
1141 * If the receiver does not find a STCB for a packet containing an AUTH
1142 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1143 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1146 * This means that any chunks that can help us identify the association need
1147 * to be looked at to find this association.
1149 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
1150 struct sk_buff *skb,
1151 const union sctp_addr *laddr,
1152 struct sctp_transport **transportp)
1154 struct sctp_association *asoc = NULL;
1155 struct sctp_chunkhdr *ch;
1157 unsigned int chunk_num = 1;
1160 /* Walk through the chunks looking for AUTH or ASCONF chunks
1161 * to help us find the association.
1163 ch = (struct sctp_chunkhdr *)skb->data;
1165 /* Break out if chunk length is less then minimal. */
1166 if (ntohs(ch->length) < sizeof(*ch))
1169 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
1170 if (ch_end > skb_tail_pointer(skb))
1175 have_auth = chunk_num;
1178 case SCTP_CID_COOKIE_ECHO:
1179 /* If a packet arrives containing an AUTH chunk as
1180 * a first chunk, a COOKIE-ECHO chunk as the second
1181 * chunk, and possibly more chunks after them, and
1182 * the receiver does not have an STCB for that
1183 * packet, then authentication is based on
1184 * the contents of the COOKIE- ECHO chunk.
1186 if (have_auth == 1 && chunk_num == 2)
1190 case SCTP_CID_ASCONF:
1191 if (have_auth || net->sctp.addip_noauth)
1192 asoc = __sctp_rcv_asconf_lookup(
1194 sctp_hdr(skb)->source,
1203 ch = (struct sctp_chunkhdr *)ch_end;
1205 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb));
1211 * There are circumstances when we need to look inside the SCTP packet
1212 * for information to help us find the association. Examples
1213 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1216 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
1217 struct sk_buff *skb,
1218 const union sctp_addr *laddr,
1219 struct sctp_transport **transportp)
1221 struct sctp_chunkhdr *ch;
1223 /* We do not allow GSO frames here as we need to linearize and
1224 * then cannot guarantee frame boundaries. This shouldn't be an
1225 * issue as packets hitting this are mostly INIT or INIT-ACK and
1226 * those cannot be on GSO-style anyway.
1228 if ((skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) == SKB_GSO_SCTP)
1231 ch = (struct sctp_chunkhdr *)skb->data;
1233 /* The code below will attempt to walk the chunk and extract
1234 * parameter information. Before we do that, we need to verify
1235 * that the chunk length doesn't cause overflow. Otherwise, we'll
1238 if (SCTP_PAD4(ntohs(ch->length)) > skb->len)
1241 /* If this is INIT/INIT-ACK look inside the chunk too. */
1242 if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
1243 return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
1245 return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
1248 /* Lookup an association for an inbound skb. */
1249 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1250 struct sk_buff *skb,
1251 const union sctp_addr *paddr,
1252 const union sctp_addr *laddr,
1253 struct sctp_transport **transportp)
1255 struct sctp_association *asoc;
1257 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1261 /* Further lookup for INIT/INIT-ACK packets.
1262 * SCTP Implementors Guide, 2.18 Handling of address
1263 * parameters within the INIT or INIT-ACK.
1265 asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);
1269 if (paddr->sa.sa_family == AF_INET)
1270 pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n",
1271 &laddr->v4.sin_addr, ntohs(laddr->v4.sin_port),
1272 &paddr->v4.sin_addr, ntohs(paddr->v4.sin_port));
1274 pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n",
1275 &laddr->v6.sin6_addr, ntohs(laddr->v6.sin6_port),
1276 &paddr->v6.sin6_addr, ntohs(paddr->v6.sin6_port));