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);
93 struct sctp_input_cb {
95 struct inet_skb_parm h4;
96 #if IS_ENABLED(CONFIG_IPV6)
97 struct inet6_skb_parm h6;
100 struct sctp_chunk *chunk;
102 #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
105 * This is the routine which IP calls when receiving an SCTP packet.
107 int sctp_rcv(struct sk_buff *skb)
110 struct sctp_association *asoc;
111 struct sctp_endpoint *ep = NULL;
112 struct sctp_ep_common *rcvr;
113 struct sctp_transport *transport = NULL;
114 struct sctp_chunk *chunk;
116 union sctp_addr dest;
119 struct net *net = dev_net(skb->dev);
121 if (skb->pkt_type != PACKET_HOST)
124 __SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS);
126 if (skb_linearize(skb))
129 /* Pull up the IP and SCTP headers. */
130 __skb_pull(skb, skb_transport_offset(skb));
131 if (skb->len < sizeof(struct sctphdr))
134 skb->csum_valid = 0; /* Previous value not applicable */
135 if (skb_csum_unnecessary(skb))
136 __skb_decr_checksum_unnecessary(skb);
137 else if (!sctp_checksum_disable && sctp_rcv_checksum(net, skb) < 0)
141 skb_pull(skb, sizeof(struct sctphdr));
143 /* Make sure we at least have chunk headers worth of data left. */
144 if (skb->len < sizeof(struct sctp_chunkhdr))
147 family = ipver2af(ip_hdr(skb)->version);
148 af = sctp_get_af_specific(family);
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 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) {
186 sctp_association_put(asoc);
189 sctp_endpoint_put(ep);
192 sk = net->sctp.ctl_sock;
193 ep = sctp_sk(sk)->ep;
194 sctp_endpoint_hold(ep);
199 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
200 * An SCTP packet is called an "out of the blue" (OOTB)
201 * packet if it is correctly formed, i.e., passed the
202 * receiver's checksum check, but the receiver is not
203 * able to identify the association to which this
207 if (sctp_rcv_ootb(skb)) {
208 __SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
209 goto discard_release;
213 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
214 goto discard_release;
217 if (sk_filter(sk, skb))
218 goto discard_release;
220 /* Create an SCTP packet structure. */
221 chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC);
223 goto discard_release;
224 SCTP_INPUT_CB(skb)->chunk = chunk;
226 /* Remember what endpoint is to handle this packet. */
229 /* Remember the SCTP header. */
230 chunk->sctp_hdr = sctp_hdr(skb);
232 /* Set the source and destination addresses of the incoming chunk. */
233 sctp_init_addrs(chunk, &src, &dest);
235 /* Remember where we came from. */
236 chunk->transport = transport;
238 /* Acquire access to the sock lock. Note: We are safe from other
239 * bottom halves on this lock, but a user may be in the lock too,
240 * so check if it is busy.
244 if (sk != rcvr->sk) {
245 /* Our cached sk is different from the rcvr->sk. This is
246 * because migrate()/accept() may have moved the association
247 * to a new socket and released all the sockets. So now we
248 * are holding a lock on the old socket while the user may
249 * be doing something with the new socket. Switch our veiw
257 if (sock_owned_by_user(sk)) {
258 if (sctp_add_backlog(sk, skb)) {
260 sctp_chunk_free(chunk);
261 skb = NULL; /* sctp_chunk_free already freed the skb */
262 goto discard_release;
264 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG);
266 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ);
267 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
272 /* Release the asoc/ep ref we took in the lookup calls. */
274 sctp_association_put(asoc);
276 sctp_endpoint_put(ep);
281 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
286 /* Release the asoc/ep ref we took in the lookup calls. */
288 sctp_association_put(asoc);
290 sctp_endpoint_put(ep);
295 /* Process the backlog queue of the socket. Every skb on
296 * the backlog holds a ref on an association or endpoint.
297 * We hold this ref throughout the state machine to make
298 * sure that the structure we need is still around.
300 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
302 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
303 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
304 struct sctp_ep_common *rcvr = NULL;
309 /* If the rcvr is dead then the association or endpoint
310 * has been deleted and we can safely drop the chunk
311 * and refs that we are holding.
314 sctp_chunk_free(chunk);
318 if (unlikely(rcvr->sk != sk)) {
319 /* In this case, the association moved from one socket to
320 * another. We are currently sitting on the backlog of the
321 * old socket, so we need to move.
322 * However, since we are here in the process context we
323 * need to take make sure that the user doesn't own
324 * the new socket when we process the packet.
325 * If the new socket is user-owned, queue the chunk to the
326 * backlog of the new socket without dropping any refs.
327 * Otherwise, we can safely push the chunk on the inqueue.
333 if (sock_owned_by_user(sk)) {
334 if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
335 sctp_chunk_free(chunk);
339 sctp_inq_push(inqueue, chunk);
343 /* If the chunk was backloged again, don't drop refs */
347 sctp_inq_push(inqueue, chunk);
351 /* Release the refs we took in sctp_add_backlog */
352 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
353 sctp_association_put(sctp_assoc(rcvr));
354 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
355 sctp_endpoint_put(sctp_ep(rcvr));
362 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
364 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
365 struct sctp_ep_common *rcvr = chunk->rcvr;
368 ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
370 /* Hold the assoc/ep while hanging on the backlog queue.
371 * This way, we know structures we need will not disappear
374 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
375 sctp_association_hold(sctp_assoc(rcvr));
376 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
377 sctp_endpoint_hold(sctp_ep(rcvr));
385 /* Handle icmp frag needed error. */
386 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
387 struct sctp_transport *t, __u32 pmtu)
389 if (!t || (t->pathmtu <= pmtu))
392 if (sock_owned_by_user(sk)) {
393 asoc->pmtu_pending = 1;
398 if (t->param_flags & SPP_PMTUD_ENABLE) {
399 /* Update transports view of the MTU */
400 sctp_transport_update_pmtu(sk, t, pmtu);
402 /* Update association pmtu. */
403 sctp_assoc_sync_pmtu(sk, asoc);
406 /* Retransmit with the new pmtu setting.
407 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
408 * Needed will never be sent, but if a message was sent before
409 * PMTU discovery was disabled that was larger than the PMTU, it
410 * would not be fragmented, so it must be re-transmitted fragmented.
412 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
415 void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
418 struct dst_entry *dst;
422 dst = sctp_transport_dst_check(t);
424 dst->ops->redirect(dst, sk, skb);
428 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
430 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
431 * or a "Protocol Unreachable" treat this message as an abort
432 * with the T bit set.
434 * This function sends an event to the state machine, which will abort the
438 void sctp_icmp_proto_unreachable(struct sock *sk,
439 struct sctp_association *asoc,
440 struct sctp_transport *t)
442 if (sock_owned_by_user(sk)) {
443 if (timer_pending(&t->proto_unreach_timer))
446 if (!mod_timer(&t->proto_unreach_timer,
448 sctp_association_hold(asoc);
451 struct net *net = sock_net(sk);
453 pr_debug("%s: unrecognized next header type "
454 "encountered!\n", __func__);
456 if (del_timer(&t->proto_unreach_timer))
457 sctp_association_put(asoc);
459 sctp_do_sm(net, SCTP_EVENT_T_OTHER,
460 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
461 asoc->state, asoc->ep, asoc, t,
466 /* Common lookup code for icmp/icmpv6 error handler. */
467 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
468 struct sctphdr *sctphdr,
469 struct sctp_association **app,
470 struct sctp_transport **tpp)
472 union sctp_addr saddr;
473 union sctp_addr daddr;
475 struct sock *sk = NULL;
476 struct sctp_association *asoc;
477 struct sctp_transport *transport = NULL;
478 struct sctp_init_chunk *chunkhdr;
479 __u32 vtag = ntohl(sctphdr->vtag);
480 int len = skb->len - ((void *)sctphdr - (void *)skb->data);
482 *app = NULL; *tpp = NULL;
484 af = sctp_get_af_specific(family);
489 /* Initialize local addresses for lookups. */
490 af->from_skb(&saddr, skb, 1);
491 af->from_skb(&daddr, skb, 0);
493 /* Look for an association that matches the incoming ICMP error
496 asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport);
502 /* RFC 4960, Appendix C. ICMP Handling
504 * ICMP6) An implementation MUST validate that the Verification Tag
505 * contained in the ICMP message matches the Verification Tag of
506 * the peer. If the Verification Tag is not 0 and does NOT
507 * match, discard the ICMP message. If it is 0 and the ICMP
508 * message contains enough bytes to verify that the chunk type is
509 * an INIT chunk and that the Initiate Tag matches the tag of the
510 * peer, continue with ICMP7. If the ICMP message is too short
511 * or the chunk type or the Initiate Tag does not match, silently
512 * discard the packet.
515 chunkhdr = (void *)sctphdr + sizeof(struct sctphdr);
516 if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
518 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
519 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
522 } else if (vtag != asoc->c.peer_vtag) {
528 /* If too many ICMPs get dropped on busy
529 * servers this needs to be solved differently.
531 if (sock_owned_by_user(sk))
532 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
539 sctp_association_put(asoc);
543 /* Common cleanup code for icmp/icmpv6 error handler. */
544 void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
547 sctp_association_put(asoc);
551 * This routine is called by the ICMP module when it gets some
552 * sort of error condition. If err < 0 then the socket should
553 * be closed and the error returned to the user. If err > 0
554 * it's just the icmp type << 8 | icmp code. After adjustment
555 * header points to the first 8 bytes of the sctp header. We need
556 * to find the appropriate port.
558 * The locking strategy used here is very "optimistic". When
559 * someone else accesses the socket the ICMP is just dropped
560 * and for some paths there is no check at all.
561 * A more general error queue to queue errors for later handling
562 * is probably better.
565 void sctp_v4_err(struct sk_buff *skb, __u32 info)
567 const struct iphdr *iph = (const struct iphdr *)skb->data;
568 const int ihlen = iph->ihl * 4;
569 const int type = icmp_hdr(skb)->type;
570 const int code = icmp_hdr(skb)->code;
572 struct sctp_association *asoc = NULL;
573 struct sctp_transport *transport;
574 struct inet_sock *inet;
575 __u16 saveip, savesctp;
577 struct net *net = dev_net(skb->dev);
579 /* Fix up skb to look at the embedded net header. */
580 saveip = skb->network_header;
581 savesctp = skb->transport_header;
582 skb_reset_network_header(skb);
583 skb_set_transport_header(skb, ihlen);
584 sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
585 /* Put back, the original values. */
586 skb->network_header = saveip;
587 skb->transport_header = savesctp;
589 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
592 /* Warning: The sock lock is held. Remember to call
597 case ICMP_PARAMETERPROB:
600 case ICMP_DEST_UNREACH:
601 if (code > NR_ICMP_UNREACH)
604 /* PMTU discovery (RFC1191) */
605 if (ICMP_FRAG_NEEDED == code) {
606 sctp_icmp_frag_needed(sk, asoc, transport,
610 if (ICMP_PROT_UNREACH == code) {
611 sctp_icmp_proto_unreachable(sk, asoc,
616 err = icmp_err_convert[code].errno;
618 case ICMP_TIME_EXCEEDED:
619 /* Ignore any time exceeded errors due to fragment reassembly
622 if (ICMP_EXC_FRAGTIME == code)
628 sctp_icmp_redirect(sk, transport, skb);
629 /* Fall through to out_unlock. */
635 if (!sock_owned_by_user(sk) && inet->recverr) {
637 sk->sk_error_report(sk);
638 } else { /* Only an error on timeout */
639 sk->sk_err_soft = err;
643 sctp_err_finish(sk, asoc);
647 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
649 * This function scans all the chunks in the OOTB packet to determine if
650 * the packet should be discarded right away. If a response might be needed
651 * for this packet, or, if further processing is possible, the packet will
652 * be queued to a proper inqueue for the next phase of handling.
655 * Return 0 - If further processing is needed.
656 * Return 1 - If the packet can be discarded right away.
658 static int sctp_rcv_ootb(struct sk_buff *skb)
663 ch = (sctp_chunkhdr_t *) skb->data;
665 /* Scan through all the chunks in the packet. */
667 /* Break out if chunk length is less then minimal. */
668 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
671 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
672 if (ch_end > skb_tail_pointer(skb))
675 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
676 * receiver MUST silently discard the OOTB packet and take no
679 if (SCTP_CID_ABORT == ch->type)
682 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
683 * chunk, the receiver should silently discard the packet
684 * and take no further action.
686 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
690 * This will discard packets with INIT chunk bundled as
691 * subsequent chunks in the packet. When INIT is first,
692 * the normal INIT processing will discard the chunk.
694 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
697 ch = (sctp_chunkhdr_t *) ch_end;
698 } while (ch_end < skb_tail_pointer(skb));
706 /* Insert endpoint into the hash table. */
707 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
709 struct net *net = sock_net(ep->base.sk);
710 struct sctp_ep_common *epb;
711 struct sctp_hashbucket *head;
715 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
716 head = &sctp_ep_hashtable[epb->hashent];
718 write_lock(&head->lock);
719 hlist_add_head(&epb->node, &head->chain);
720 write_unlock(&head->lock);
723 /* Add an endpoint to the hash. Local BH-safe. */
724 void sctp_hash_endpoint(struct sctp_endpoint *ep)
727 __sctp_hash_endpoint(ep);
731 /* Remove endpoint from the hash table. */
732 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
734 struct net *net = sock_net(ep->base.sk);
735 struct sctp_hashbucket *head;
736 struct sctp_ep_common *epb;
740 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
742 head = &sctp_ep_hashtable[epb->hashent];
744 write_lock(&head->lock);
745 hlist_del_init(&epb->node);
746 write_unlock(&head->lock);
749 /* Remove endpoint from the hash. Local BH-safe. */
750 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
753 __sctp_unhash_endpoint(ep);
757 /* Look up an endpoint. */
758 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
759 const union sctp_addr *laddr)
761 struct sctp_hashbucket *head;
762 struct sctp_ep_common *epb;
763 struct sctp_endpoint *ep;
766 hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
767 head = &sctp_ep_hashtable[hash];
768 read_lock(&head->lock);
769 sctp_for_each_hentry(epb, &head->chain) {
771 if (sctp_endpoint_is_match(ep, net, laddr))
775 ep = sctp_sk(net->sctp.ctl_sock)->ep;
778 sctp_endpoint_hold(ep);
779 read_unlock(&head->lock);
783 /* rhashtable for transport */
784 struct sctp_hash_cmp_arg {
785 const struct sctp_endpoint *ep;
786 const union sctp_addr *laddr;
787 const union sctp_addr *paddr;
788 const struct net *net;
791 static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
794 const struct sctp_hash_cmp_arg *x = arg->key;
795 const struct sctp_transport *t = ptr;
796 struct sctp_association *asoc = t->asoc;
797 const struct net *net = x->net;
799 if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr))
801 if (!net_eq(sock_net(asoc->base.sk), net))
804 if (x->ep != asoc->ep)
807 if (x->laddr->v4.sin_port != htons(asoc->base.bind_addr.port))
809 if (!sctp_bind_addr_match(&asoc->base.bind_addr,
810 x->laddr, sctp_sk(asoc->base.sk)))
817 static inline u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
819 const struct sctp_transport *t = data;
820 const union sctp_addr *paddr = &t->ipaddr;
821 const struct net *net = sock_net(t->asoc->base.sk);
822 u16 lport = htons(t->asoc->base.bind_addr.port);
825 if (paddr->sa.sa_family == AF_INET6)
826 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
828 addr = paddr->v4.sin_addr.s_addr;
830 return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 |
831 (__force __u32)lport, net_hash_mix(net), seed);
834 static inline u32 sctp_hash_key(const void *data, u32 len, u32 seed)
836 const struct sctp_hash_cmp_arg *x = data;
837 const union sctp_addr *paddr = x->paddr;
838 const struct net *net = x->net;
842 lport = x->ep ? htons(x->ep->base.bind_addr.port) :
843 x->laddr->v4.sin_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 const struct rhashtable_params sctp_hash_params = {
854 .head_offset = offsetof(struct sctp_transport, node),
855 .hashfn = sctp_hash_key,
856 .obj_hashfn = sctp_hash_obj,
857 .obj_cmpfn = sctp_hash_cmp,
858 .automatic_shrinking = true,
861 int sctp_transport_hashtable_init(void)
863 return rhashtable_init(&sctp_transport_hashtable, &sctp_hash_params);
866 void sctp_transport_hashtable_destroy(void)
868 rhashtable_destroy(&sctp_transport_hashtable);
871 void sctp_hash_transport(struct sctp_transport *t)
873 struct sctp_hash_cmp_arg arg;
878 arg.ep = t->asoc->ep;
879 arg.paddr = &t->ipaddr;
880 arg.net = sock_net(t->asoc->base.sk);
883 if (rhashtable_lookup_insert_key(&sctp_transport_hashtable, &arg,
884 &t->node, sctp_hash_params) == -EBUSY)
888 void sctp_unhash_transport(struct sctp_transport *t)
893 rhashtable_remove_fast(&sctp_transport_hashtable, &t->node,
897 struct sctp_transport *sctp_addrs_lookup_transport(
899 const union sctp_addr *laddr,
900 const union sctp_addr *paddr)
902 struct sctp_hash_cmp_arg arg = {
909 return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
913 struct sctp_transport *sctp_epaddr_lookup_transport(
914 const struct sctp_endpoint *ep,
915 const union sctp_addr *paddr)
917 struct net *net = sock_net(ep->base.sk);
918 struct sctp_hash_cmp_arg arg = {
924 return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
928 /* Look up an association. */
929 static struct sctp_association *__sctp_lookup_association(
931 const union sctp_addr *local,
932 const union sctp_addr *peer,
933 struct sctp_transport **pt)
935 struct sctp_transport *t;
936 struct sctp_association *asoc = NULL;
938 t = sctp_addrs_lookup_transport(net, local, peer);
939 if (!t || !sctp_transport_hold(t))
943 sctp_association_hold(asoc);
946 sctp_transport_put(t);
952 /* Look up an association. protected by RCU read lock */
954 struct sctp_association *sctp_lookup_association(struct net *net,
955 const union sctp_addr *laddr,
956 const union sctp_addr *paddr,
957 struct sctp_transport **transportp)
959 struct sctp_association *asoc;
962 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
968 /* Is there an association matching the given local and peer addresses? */
969 int sctp_has_association(struct net *net,
970 const union sctp_addr *laddr,
971 const union sctp_addr *paddr)
973 struct sctp_association *asoc;
974 struct sctp_transport *transport;
976 if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) {
977 sctp_association_put(asoc);
985 * SCTP Implementors Guide, 2.18 Handling of address
986 * parameters within the INIT or INIT-ACK.
988 * D) When searching for a matching TCB upon reception of an INIT
989 * or INIT-ACK chunk the receiver SHOULD use not only the
990 * source address of the packet (containing the INIT or
991 * INIT-ACK) but the receiver SHOULD also use all valid
992 * address parameters contained within the chunk.
994 * 2.18.3 Solution description
996 * This new text clearly specifies to an implementor the need
997 * to look within the INIT or INIT-ACK. Any implementation that
998 * does not do this, may not be able to establish associations
999 * in certain circumstances.
1002 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
1003 struct sk_buff *skb,
1004 const union sctp_addr *laddr, struct sctp_transport **transportp)
1006 struct sctp_association *asoc;
1007 union sctp_addr addr;
1008 union sctp_addr *paddr = &addr;
1009 struct sctphdr *sh = sctp_hdr(skb);
1010 union sctp_params params;
1011 sctp_init_chunk_t *init;
1012 struct sctp_transport *transport;
1016 * This code will NOT touch anything inside the chunk--it is
1017 * strictly READ-ONLY.
1019 * RFC 2960 3 SCTP packet Format
1021 * Multiple chunks can be bundled into one SCTP packet up to
1022 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
1023 * COMPLETE chunks. These chunks MUST NOT be bundled with any
1024 * other chunk in a packet. See Section 6.10 for more details
1025 * on chunk bundling.
1028 /* Find the start of the TLVs and the end of the chunk. This is
1029 * the region we search for address parameters.
1031 init = (sctp_init_chunk_t *)skb->data;
1033 /* Walk the parameters looking for embedded addresses. */
1034 sctp_walk_params(params, init, init_hdr.params) {
1036 /* Note: Ignoring hostname addresses. */
1037 af = sctp_get_af_specific(param_type2af(params.p->type));
1041 af->from_addr_param(paddr, params.addr, sh->source, 0);
1043 asoc = __sctp_lookup_association(net, laddr, paddr, &transport);
1051 /* ADD-IP, Section 5.2
1052 * When an endpoint receives an ASCONF Chunk from the remote peer
1053 * special procedures may be needed to identify the association the
1054 * ASCONF Chunk is associated with. To properly find the association
1055 * the following procedures SHOULD be followed:
1057 * D2) If the association is not found, use the address found in the
1058 * Address Parameter TLV combined with the port number found in the
1059 * SCTP common header. If found proceed to rule D4.
1061 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1062 * address found in the ASCONF Address Parameter TLV of each of the
1063 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1065 static struct sctp_association *__sctp_rcv_asconf_lookup(
1067 sctp_chunkhdr_t *ch,
1068 const union sctp_addr *laddr,
1070 struct sctp_transport **transportp)
1072 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
1074 union sctp_addr_param *param;
1075 union sctp_addr paddr;
1077 /* Skip over the ADDIP header and find the Address parameter */
1078 param = (union sctp_addr_param *)(asconf + 1);
1080 af = sctp_get_af_specific(param_type2af(param->p.type));
1084 af->from_addr_param(&paddr, param, peer_port, 0);
1086 return __sctp_lookup_association(net, laddr, &paddr, transportp);
1090 /* SCTP-AUTH, Section 6.3:
1091 * If the receiver does not find a STCB for a packet containing an AUTH
1092 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1093 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1096 * This means that any chunks that can help us identify the association need
1097 * to be looked at to find this association.
1099 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
1100 struct sk_buff *skb,
1101 const union sctp_addr *laddr,
1102 struct sctp_transport **transportp)
1104 struct sctp_association *asoc = NULL;
1105 sctp_chunkhdr_t *ch;
1107 unsigned int chunk_num = 1;
1110 /* Walk through the chunks looking for AUTH or ASCONF chunks
1111 * to help us find the association.
1113 ch = (sctp_chunkhdr_t *) skb->data;
1115 /* Break out if chunk length is less then minimal. */
1116 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
1119 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
1120 if (ch_end > skb_tail_pointer(skb))
1125 have_auth = chunk_num;
1128 case SCTP_CID_COOKIE_ECHO:
1129 /* If a packet arrives containing an AUTH chunk as
1130 * a first chunk, a COOKIE-ECHO chunk as the second
1131 * chunk, and possibly more chunks after them, and
1132 * the receiver does not have an STCB for that
1133 * packet, then authentication is based on
1134 * the contents of the COOKIE- ECHO chunk.
1136 if (have_auth == 1 && chunk_num == 2)
1140 case SCTP_CID_ASCONF:
1141 if (have_auth || net->sctp.addip_noauth)
1142 asoc = __sctp_rcv_asconf_lookup(
1144 sctp_hdr(skb)->source,
1153 ch = (sctp_chunkhdr_t *) ch_end;
1155 } while (ch_end < skb_tail_pointer(skb));
1161 * There are circumstances when we need to look inside the SCTP packet
1162 * for information to help us find the association. Examples
1163 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1166 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
1167 struct sk_buff *skb,
1168 const union sctp_addr *laddr,
1169 struct sctp_transport **transportp)
1171 sctp_chunkhdr_t *ch;
1173 ch = (sctp_chunkhdr_t *) skb->data;
1175 /* The code below will attempt to walk the chunk and extract
1176 * parameter information. Before we do that, we need to verify
1177 * that the chunk length doesn't cause overflow. Otherwise, we'll
1180 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
1183 /* If this is INIT/INIT-ACK look inside the chunk too. */
1184 if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
1185 return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
1187 return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
1190 /* Lookup an association for an inbound skb. */
1191 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1192 struct sk_buff *skb,
1193 const union sctp_addr *paddr,
1194 const union sctp_addr *laddr,
1195 struct sctp_transport **transportp)
1197 struct sctp_association *asoc;
1199 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1201 /* Further lookup for INIT/INIT-ACK packets.
1202 * SCTP Implementors Guide, 2.18 Handling of address
1203 * parameters within the INIT or INIT-ACK.
1206 asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);