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>
59 #include <linux/rhashtable.h>
61 /* Forward declarations for internal helpers. */
62 static int sctp_rcv_ootb(struct sk_buff *);
63 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
65 const union sctp_addr *paddr,
66 const union sctp_addr *laddr,
67 struct sctp_transport **transportp);
68 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
69 const union sctp_addr *laddr);
70 static struct sctp_association *__sctp_lookup_association(
72 const union sctp_addr *local,
73 const union sctp_addr *peer,
74 struct sctp_transport **pt);
76 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
79 /* Calculate the SCTP checksum of an SCTP packet. */
80 static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb)
82 struct sctphdr *sh = sctp_hdr(skb);
83 __le32 cmp = sh->checksum;
84 __le32 val = sctp_compute_cksum(skb, 0);
87 /* CRC failure, dump it. */
88 __SCTP_INC_STATS(net, SCTP_MIB_CHECKSUMERRORS);
95 * This is the routine which IP calls when receiving an SCTP packet.
97 int sctp_rcv(struct sk_buff *skb)
100 struct sctp_association *asoc;
101 struct sctp_endpoint *ep = NULL;
102 struct sctp_ep_common *rcvr;
103 struct sctp_transport *transport = NULL;
104 struct sctp_chunk *chunk;
106 union sctp_addr dest;
110 struct net *net = dev_net(skb->dev);
111 bool is_gso = skb_is_gso(skb) && skb_is_gso_sctp(skb);
113 if (skb->pkt_type != PACKET_HOST)
116 __SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS);
118 /* If packet is too small to contain a single chunk, let's not
119 * waste time on it anymore.
121 if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) +
122 skb_transport_offset(skb))
125 /* If the packet is fragmented and we need to do crc checking,
126 * it's better to just linearize it otherwise crc computing
129 if ((!is_gso && skb_linearize(skb)) ||
130 !pskb_may_pull(skb, sizeof(struct sctphdr)))
133 /* Pull up the IP header. */
134 __skb_pull(skb, skb_transport_offset(skb));
136 skb->csum_valid = 0; /* Previous value not applicable */
137 if (skb_csum_unnecessary(skb))
138 __skb_decr_checksum_unnecessary(skb);
139 else if (!sctp_checksum_disable &&
141 sctp_rcv_checksum(net, skb) < 0)
145 __skb_pull(skb, sizeof(struct sctphdr));
147 family = ipver2af(ip_hdr(skb)->version);
148 af = sctp_get_af_specific(family);
151 SCTP_INPUT_CB(skb)->af = af;
153 /* Initialize local addresses for lookups. */
154 af->from_skb(&src, skb, 1);
155 af->from_skb(&dest, skb, 0);
157 /* If the packet is to or from a non-unicast address,
158 * silently discard the packet.
160 * This is not clearly defined in the RFC except in section
161 * 8.4 - OOTB handling. However, based on the book "Stream Control
162 * Transmission Protocol" 2.1, "It is important to note that the
163 * IP address of an SCTP transport address must be a routable
164 * unicast address. In other words, IP multicast addresses and
165 * IP broadcast addresses cannot be used in an SCTP transport
168 if (!af->addr_valid(&src, NULL, skb) ||
169 !af->addr_valid(&dest, NULL, skb))
172 asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
175 ep = __sctp_rcv_lookup_endpoint(net, &dest);
177 /* Retrieve the common input handling substructure. */
178 rcvr = asoc ? &asoc->base : &ep->base;
182 * If a frame arrives on an interface and the receiving socket is
183 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
185 bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
186 if (bound_dev_if && (bound_dev_if != af->skb_iif(skb))) {
188 sctp_transport_put(transport);
192 sctp_endpoint_put(ep);
195 sk = net->sctp.ctl_sock;
196 ep = sctp_sk(sk)->ep;
197 sctp_endpoint_hold(ep);
202 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
203 * An SCTP packet is called an "out of the blue" (OOTB)
204 * packet if it is correctly formed, i.e., passed the
205 * receiver's checksum check, but the receiver is not
206 * able to identify the association to which this
210 if (sctp_rcv_ootb(skb)) {
211 __SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
212 goto discard_release;
216 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
217 goto discard_release;
220 if (sk_filter(sk, skb))
221 goto discard_release;
223 /* Create an SCTP packet structure. */
224 chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC);
226 goto discard_release;
227 SCTP_INPUT_CB(skb)->chunk = chunk;
229 /* Remember what endpoint is to handle this packet. */
232 /* Remember the SCTP header. */
233 chunk->sctp_hdr = sctp_hdr(skb);
235 /* Set the source and destination addresses of the incoming chunk. */
236 sctp_init_addrs(chunk, &src, &dest);
238 /* Remember where we came from. */
239 chunk->transport = transport;
241 /* Acquire access to the sock lock. Note: We are safe from other
242 * bottom halves on this lock, but a user may be in the lock too,
243 * so check if it is busy.
247 if (sk != rcvr->sk) {
248 /* Our cached sk is different from the rcvr->sk. This is
249 * because migrate()/accept() may have moved the association
250 * to a new socket and released all the sockets. So now we
251 * are holding a lock on the old socket while the user may
252 * be doing something with the new socket. Switch our veiw
260 if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
261 if (sctp_add_backlog(sk, skb)) {
263 sctp_chunk_free(chunk);
264 skb = NULL; /* sctp_chunk_free already freed the skb */
265 goto discard_release;
267 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG);
269 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ);
270 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
275 /* Release the asoc/ep ref we took in the lookup calls. */
277 sctp_transport_put(transport);
279 sctp_endpoint_put(ep);
284 __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
289 /* Release the asoc/ep ref we took in the lookup calls. */
291 sctp_transport_put(transport);
293 sctp_endpoint_put(ep);
298 /* Process the backlog queue of the socket. Every skb on
299 * the backlog holds a ref on an association or endpoint.
300 * We hold this ref throughout the state machine to make
301 * sure that the structure we need is still around.
303 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
305 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
306 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
307 struct sctp_transport *t = chunk->transport;
308 struct sctp_ep_common *rcvr = NULL;
313 /* If the rcvr is dead then the association or endpoint
314 * has been deleted and we can safely drop the chunk
315 * and refs that we are holding.
318 sctp_chunk_free(chunk);
322 if (unlikely(rcvr->sk != sk)) {
323 /* In this case, the association moved from one socket to
324 * another. We are currently sitting on the backlog of the
325 * old socket, so we need to move.
326 * However, since we are here in the process context we
327 * need to take make sure that the user doesn't own
328 * the new socket when we process the packet.
329 * If the new socket is user-owned, queue the chunk to the
330 * backlog of the new socket without dropping any refs.
331 * Otherwise, we can safely push the chunk on the inqueue.
338 if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
339 if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
340 sctp_chunk_free(chunk);
344 sctp_inq_push(inqueue, chunk);
349 /* If the chunk was backloged again, don't drop refs */
353 if (!sctp_newsk_ready(sk)) {
354 if (!sk_add_backlog(sk, skb, sk->sk_rcvbuf))
356 sctp_chunk_free(chunk);
358 sctp_inq_push(inqueue, chunk);
363 /* Release the refs we took in sctp_add_backlog */
364 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
365 sctp_transport_put(t);
366 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
367 sctp_endpoint_put(sctp_ep(rcvr));
374 static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
376 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
377 struct sctp_transport *t = chunk->transport;
378 struct sctp_ep_common *rcvr = chunk->rcvr;
381 ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
383 /* Hold the assoc/ep while hanging on the backlog queue.
384 * This way, we know structures we need will not disappear
387 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
388 sctp_transport_hold(t);
389 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
390 sctp_endpoint_hold(sctp_ep(rcvr));
398 /* Handle icmp frag needed error. */
399 void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
400 struct sctp_transport *t, __u32 pmtu)
402 if (!t || (t->pathmtu <= pmtu))
405 if (sock_owned_by_user(sk)) {
406 atomic_set(&t->mtu_info, pmtu);
407 asoc->pmtu_pending = 1;
412 if (!(t->param_flags & SPP_PMTUD_ENABLE))
413 /* We can't allow retransmitting in such case, as the
414 * retransmission would be sized just as before, and thus we
415 * would get another icmp, and retransmit again.
419 /* Update transports view of the MTU. Return if no update was needed.
420 * If an update wasn't needed/possible, it also doesn't make sense to
421 * try to retransmit now.
423 if (!sctp_transport_update_pmtu(t, pmtu))
426 /* Update association pmtu. */
427 sctp_assoc_sync_pmtu(asoc);
429 /* Retransmit with the new pmtu setting. */
430 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
433 void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
436 struct dst_entry *dst;
438 if (sock_owned_by_user(sk) || !t)
440 dst = sctp_transport_dst_check(t);
442 dst->ops->redirect(dst, sk, skb);
446 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
448 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
449 * or a "Protocol Unreachable" treat this message as an abort
450 * with the T bit set.
452 * This function sends an event to the state machine, which will abort the
456 void sctp_icmp_proto_unreachable(struct sock *sk,
457 struct sctp_association *asoc,
458 struct sctp_transport *t)
460 if (sock_owned_by_user(sk)) {
461 if (timer_pending(&t->proto_unreach_timer))
464 if (!mod_timer(&t->proto_unreach_timer,
466 sctp_transport_hold(t);
469 struct net *net = sock_net(sk);
471 pr_debug("%s: unrecognized next header type "
472 "encountered!\n", __func__);
474 if (del_timer(&t->proto_unreach_timer))
475 sctp_transport_put(t);
477 sctp_do_sm(net, SCTP_EVENT_T_OTHER,
478 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
479 asoc->state, asoc->ep, asoc, t,
484 /* Common lookup code for icmp/icmpv6 error handler. */
485 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
486 struct sctphdr *sctphdr,
487 struct sctp_association **app,
488 struct sctp_transport **tpp)
490 struct sctp_init_chunk *chunkhdr, _chunkhdr;
491 union sctp_addr saddr;
492 union sctp_addr daddr;
494 struct sock *sk = NULL;
495 struct sctp_association *asoc;
496 struct sctp_transport *transport = NULL;
497 __u32 vtag = ntohl(sctphdr->vtag);
499 *app = NULL; *tpp = NULL;
501 af = sctp_get_af_specific(family);
506 /* Initialize local addresses for lookups. */
507 af->from_skb(&saddr, skb, 1);
508 af->from_skb(&daddr, skb, 0);
510 /* Look for an association that matches the incoming ICMP error
513 asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport);
519 /* RFC 4960, Appendix C. ICMP Handling
521 * ICMP6) An implementation MUST validate that the Verification Tag
522 * contained in the ICMP message matches the Verification Tag of
523 * the peer. If the Verification Tag is not 0 and does NOT
524 * match, discard the ICMP message. If it is 0 and the ICMP
525 * message contains enough bytes to verify that the chunk type is
526 * an INIT chunk and that the Initiate Tag matches the tag of the
527 * peer, continue with ICMP7. If the ICMP message is too short
528 * or the chunk type or the Initiate Tag does not match, silently
529 * discard the packet.
532 /* chunk header + first 4 octects of init header */
533 chunkhdr = skb_header_pointer(skb, skb_transport_offset(skb) +
534 sizeof(struct sctphdr),
535 sizeof(struct sctp_chunkhdr) +
536 sizeof(__be32), &_chunkhdr);
538 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
539 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag)
542 } else if (vtag != asoc->c.peer_vtag) {
548 /* If too many ICMPs get dropped on busy
549 * servers this needs to be solved differently.
551 if (sock_owned_by_user(sk))
552 __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS);
559 sctp_transport_put(transport);
563 /* Common cleanup code for icmp/icmpv6 error handler. */
564 void sctp_err_finish(struct sock *sk, struct sctp_transport *t)
567 sctp_transport_put(t);
571 * This routine is called by the ICMP module when it gets some
572 * sort of error condition. If err < 0 then the socket should
573 * be closed and the error returned to the user. If err > 0
574 * it's just the icmp type << 8 | icmp code. After adjustment
575 * header points to the first 8 bytes of the sctp header. We need
576 * to find the appropriate port.
578 * The locking strategy used here is very "optimistic". When
579 * someone else accesses the socket the ICMP is just dropped
580 * and for some paths there is no check at all.
581 * A more general error queue to queue errors for later handling
582 * is probably better.
585 void sctp_v4_err(struct sk_buff *skb, __u32 info)
587 const struct iphdr *iph = (const struct iphdr *)skb->data;
588 const int ihlen = iph->ihl * 4;
589 const int type = icmp_hdr(skb)->type;
590 const int code = icmp_hdr(skb)->code;
592 struct sctp_association *asoc = NULL;
593 struct sctp_transport *transport;
594 struct inet_sock *inet;
595 __u16 saveip, savesctp;
597 struct net *net = dev_net(skb->dev);
599 /* Fix up skb to look at the embedded net header. */
600 saveip = skb->network_header;
601 savesctp = skb->transport_header;
602 skb_reset_network_header(skb);
603 skb_set_transport_header(skb, ihlen);
604 sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
605 /* Put back, the original values. */
606 skb->network_header = saveip;
607 skb->transport_header = savesctp;
609 __ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
612 /* Warning: The sock lock is held. Remember to call
617 case ICMP_PARAMETERPROB:
620 case ICMP_DEST_UNREACH:
621 if (code > NR_ICMP_UNREACH)
624 /* PMTU discovery (RFC1191) */
625 if (ICMP_FRAG_NEEDED == code) {
626 sctp_icmp_frag_needed(sk, asoc, transport,
630 if (ICMP_PROT_UNREACH == code) {
631 sctp_icmp_proto_unreachable(sk, asoc,
636 err = icmp_err_convert[code].errno;
638 case ICMP_TIME_EXCEEDED:
639 /* Ignore any time exceeded errors due to fragment reassembly
642 if (ICMP_EXC_FRAGTIME == code)
648 sctp_icmp_redirect(sk, transport, skb);
649 /* Fall through to out_unlock. */
655 if (!sock_owned_by_user(sk) && inet->recverr) {
657 sk->sk_error_report(sk);
658 } else { /* Only an error on timeout */
659 sk->sk_err_soft = err;
663 sctp_err_finish(sk, transport);
667 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
669 * This function scans all the chunks in the OOTB packet to determine if
670 * the packet should be discarded right away. If a response might be needed
671 * for this packet, or, if further processing is possible, the packet will
672 * be queued to a proper inqueue for the next phase of handling.
675 * Return 0 - If further processing is needed.
676 * Return 1 - If the packet can be discarded right away.
678 static int sctp_rcv_ootb(struct sk_buff *skb)
680 struct sctp_chunkhdr *ch, _ch;
681 int ch_end, offset = 0;
683 /* Scan through all the chunks in the packet. */
685 /* Make sure we have at least the header there */
686 if (offset + sizeof(_ch) > skb->len)
689 ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch);
691 /* Break out if chunk length is less then minimal. */
692 if (!ch || ntohs(ch->length) < sizeof(_ch))
695 ch_end = offset + SCTP_PAD4(ntohs(ch->length));
696 if (ch_end > skb->len)
699 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
700 * receiver MUST silently discard the OOTB packet and take no
703 if (SCTP_CID_ABORT == ch->type)
706 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
707 * chunk, the receiver should silently discard the packet
708 * and take no further action.
710 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
714 * This will discard packets with INIT chunk bundled as
715 * subsequent chunks in the packet. When INIT is first,
716 * the normal INIT processing will discard the chunk.
718 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
722 } while (ch_end < skb->len);
730 /* Insert endpoint into the hash table. */
731 static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
733 struct net *net = sock_net(ep->base.sk);
734 struct sctp_ep_common *epb;
735 struct sctp_hashbucket *head;
739 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
740 head = &sctp_ep_hashtable[epb->hashent];
742 write_lock(&head->lock);
743 hlist_add_head(&epb->node, &head->chain);
744 write_unlock(&head->lock);
747 /* Add an endpoint to the hash. Local BH-safe. */
748 void sctp_hash_endpoint(struct sctp_endpoint *ep)
751 __sctp_hash_endpoint(ep);
755 /* Remove endpoint from the hash table. */
756 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
758 struct net *net = sock_net(ep->base.sk);
759 struct sctp_hashbucket *head;
760 struct sctp_ep_common *epb;
764 epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
766 head = &sctp_ep_hashtable[epb->hashent];
768 write_lock(&head->lock);
769 hlist_del_init(&epb->node);
770 write_unlock(&head->lock);
773 /* Remove endpoint from the hash. Local BH-safe. */
774 void sctp_unhash_endpoint(struct sctp_endpoint *ep)
777 __sctp_unhash_endpoint(ep);
781 /* Look up an endpoint. */
782 static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
783 const union sctp_addr *laddr)
785 struct sctp_hashbucket *head;
786 struct sctp_ep_common *epb;
787 struct sctp_endpoint *ep;
790 hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
791 head = &sctp_ep_hashtable[hash];
792 read_lock(&head->lock);
793 sctp_for_each_hentry(epb, &head->chain) {
795 if (sctp_endpoint_is_match(ep, net, laddr))
799 ep = sctp_sk(net->sctp.ctl_sock)->ep;
802 sctp_endpoint_hold(ep);
803 read_unlock(&head->lock);
807 /* rhashtable for transport */
808 struct sctp_hash_cmp_arg {
809 const union sctp_addr *paddr;
810 const struct net *net;
814 static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
817 struct sctp_transport *t = (struct sctp_transport *)ptr;
818 const struct sctp_hash_cmp_arg *x = arg->key;
821 if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr))
823 if (!sctp_transport_hold(t))
826 if (!net_eq(t->asoc->base.net, x->net))
828 if (x->lport != htons(t->asoc->base.bind_addr.port))
833 sctp_transport_put(t);
837 static inline __u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
839 const struct sctp_transport *t = data;
840 const union sctp_addr *paddr = &t->ipaddr;
841 const struct net *net = t->asoc->base.net;
842 __be16 lport = htons(t->asoc->base.bind_addr.port);
845 if (paddr->sa.sa_family == AF_INET6)
846 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
848 addr = (__force __u32)paddr->v4.sin_addr.s_addr;
850 return jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
851 (__force __u32)lport, net_hash_mix(net), seed);
854 static inline __u32 sctp_hash_key(const void *data, u32 len, u32 seed)
856 const struct sctp_hash_cmp_arg *x = data;
857 const union sctp_addr *paddr = x->paddr;
858 const struct net *net = x->net;
859 __be16 lport = x->lport;
862 if (paddr->sa.sa_family == AF_INET6)
863 addr = jhash(&paddr->v6.sin6_addr, 16, seed);
865 addr = (__force __u32)paddr->v4.sin_addr.s_addr;
867 return jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
868 (__force __u32)lport, net_hash_mix(net), seed);
871 static const struct rhashtable_params sctp_hash_params = {
872 .head_offset = offsetof(struct sctp_transport, node),
873 .hashfn = sctp_hash_key,
874 .obj_hashfn = sctp_hash_obj,
875 .obj_cmpfn = sctp_hash_cmp,
876 .automatic_shrinking = true,
879 int sctp_transport_hashtable_init(void)
881 return rhltable_init(&sctp_transport_hashtable, &sctp_hash_params);
884 void sctp_transport_hashtable_destroy(void)
886 rhltable_destroy(&sctp_transport_hashtable);
889 int sctp_hash_transport(struct sctp_transport *t)
891 struct sctp_transport *transport;
892 struct rhlist_head *tmp, *list;
893 struct sctp_hash_cmp_arg arg;
899 arg.net = sock_net(t->asoc->base.sk);
900 arg.paddr = &t->ipaddr;
901 arg.lport = htons(t->asoc->base.bind_addr.port);
904 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
907 rhl_for_each_entry_rcu(transport, tmp, list, node)
908 if (transport->asoc->ep == t->asoc->ep) {
914 err = rhltable_insert_key(&sctp_transport_hashtable, &arg,
915 &t->node, sctp_hash_params);
917 pr_err_once("insert transport fail, errno %d\n", err);
922 void sctp_unhash_transport(struct sctp_transport *t)
927 rhltable_remove(&sctp_transport_hashtable, &t->node,
931 /* return a transport with holding it */
932 struct sctp_transport *sctp_addrs_lookup_transport(
934 const union sctp_addr *laddr,
935 const union sctp_addr *paddr)
937 struct rhlist_head *tmp, *list;
938 struct sctp_transport *t;
939 struct sctp_hash_cmp_arg arg = {
942 .lport = laddr->v4.sin_port,
945 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
948 rhl_for_each_entry_rcu(t, tmp, list, node) {
949 if (!sctp_transport_hold(t))
952 if (sctp_bind_addr_match(&t->asoc->base.bind_addr,
953 laddr, sctp_sk(t->asoc->base.sk)))
955 sctp_transport_put(t);
961 /* return a transport without holding it, as it's only used under sock lock */
962 struct sctp_transport *sctp_epaddr_lookup_transport(
963 const struct sctp_endpoint *ep,
964 const union sctp_addr *paddr)
966 struct net *net = sock_net(ep->base.sk);
967 struct rhlist_head *tmp, *list;
968 struct sctp_transport *t;
969 struct sctp_hash_cmp_arg arg = {
972 .lport = htons(ep->base.bind_addr.port),
975 list = rhltable_lookup(&sctp_transport_hashtable, &arg,
978 rhl_for_each_entry_rcu(t, tmp, list, node)
979 if (ep == t->asoc->ep)
985 /* Look up an association. */
986 static struct sctp_association *__sctp_lookup_association(
988 const union sctp_addr *local,
989 const union sctp_addr *peer,
990 struct sctp_transport **pt)
992 struct sctp_transport *t;
993 struct sctp_association *asoc = NULL;
995 t = sctp_addrs_lookup_transport(net, local, peer);
1006 /* Look up an association. protected by RCU read lock */
1008 struct sctp_association *sctp_lookup_association(struct net *net,
1009 const union sctp_addr *laddr,
1010 const union sctp_addr *paddr,
1011 struct sctp_transport **transportp)
1013 struct sctp_association *asoc;
1016 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1022 /* Is there an association matching the given local and peer addresses? */
1023 bool sctp_has_association(struct net *net,
1024 const union sctp_addr *laddr,
1025 const union sctp_addr *paddr)
1027 struct sctp_transport *transport;
1029 if (sctp_lookup_association(net, laddr, paddr, &transport)) {
1030 sctp_transport_put(transport);
1038 * SCTP Implementors Guide, 2.18 Handling of address
1039 * parameters within the INIT or INIT-ACK.
1041 * D) When searching for a matching TCB upon reception of an INIT
1042 * or INIT-ACK chunk the receiver SHOULD use not only the
1043 * source address of the packet (containing the INIT or
1044 * INIT-ACK) but the receiver SHOULD also use all valid
1045 * address parameters contained within the chunk.
1047 * 2.18.3 Solution description
1049 * This new text clearly specifies to an implementor the need
1050 * to look within the INIT or INIT-ACK. Any implementation that
1051 * does not do this, may not be able to establish associations
1052 * in certain circumstances.
1055 static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
1056 struct sk_buff *skb,
1057 const union sctp_addr *laddr, struct sctp_transport **transportp)
1059 struct sctp_association *asoc;
1060 union sctp_addr addr;
1061 union sctp_addr *paddr = &addr;
1062 struct sctphdr *sh = sctp_hdr(skb);
1063 union sctp_params params;
1064 struct sctp_init_chunk *init;
1068 * This code will NOT touch anything inside the chunk--it is
1069 * strictly READ-ONLY.
1071 * RFC 2960 3 SCTP packet Format
1073 * Multiple chunks can be bundled into one SCTP packet up to
1074 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
1075 * COMPLETE chunks. These chunks MUST NOT be bundled with any
1076 * other chunk in a packet. See Section 6.10 for more details
1077 * on chunk bundling.
1080 /* Find the start of the TLVs and the end of the chunk. This is
1081 * the region we search for address parameters.
1083 init = (struct sctp_init_chunk *)skb->data;
1085 /* Walk the parameters looking for embedded addresses. */
1086 sctp_walk_params(params, init, init_hdr.params) {
1088 /* Note: Ignoring hostname addresses. */
1089 af = sctp_get_af_specific(param_type2af(params.p->type));
1093 if (!af->from_addr_param(paddr, params.addr, sh->source, 0))
1096 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1104 /* ADD-IP, Section 5.2
1105 * When an endpoint receives an ASCONF Chunk from the remote peer
1106 * special procedures may be needed to identify the association the
1107 * ASCONF Chunk is associated with. To properly find the association
1108 * the following procedures SHOULD be followed:
1110 * D2) If the association is not found, use the address found in the
1111 * Address Parameter TLV combined with the port number found in the
1112 * SCTP common header. If found proceed to rule D4.
1114 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1115 * address found in the ASCONF Address Parameter TLV of each of the
1116 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1118 static struct sctp_association *__sctp_rcv_asconf_lookup(
1120 struct sctp_chunkhdr *ch,
1121 const union sctp_addr *laddr,
1123 struct sctp_transport **transportp)
1125 struct sctp_addip_chunk *asconf = (struct sctp_addip_chunk *)ch;
1127 union sctp_addr_param *param;
1128 union sctp_addr paddr;
1130 if (ntohs(ch->length) < sizeof(*asconf) + sizeof(struct sctp_paramhdr))
1133 /* Skip over the ADDIP header and find the Address parameter */
1134 param = (union sctp_addr_param *)(asconf + 1);
1136 af = sctp_get_af_specific(param_type2af(param->p.type));
1140 if (!af->from_addr_param(&paddr, param, peer_port, 0))
1143 return __sctp_lookup_association(net, laddr, &paddr, transportp);
1147 /* SCTP-AUTH, Section 6.3:
1148 * If the receiver does not find a STCB for a packet containing an AUTH
1149 * chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1150 * chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1153 * This means that any chunks that can help us identify the association need
1154 * to be looked at to find this association.
1156 static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
1157 struct sk_buff *skb,
1158 const union sctp_addr *laddr,
1159 struct sctp_transport **transportp)
1161 struct sctp_association *asoc = NULL;
1162 struct sctp_chunkhdr *ch;
1164 unsigned int chunk_num = 1;
1167 /* Walk through the chunks looking for AUTH or ASCONF chunks
1168 * to help us find the association.
1170 ch = (struct sctp_chunkhdr *)skb->data;
1172 /* Break out if chunk length is less then minimal. */
1173 if (ntohs(ch->length) < sizeof(*ch))
1176 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
1177 if (ch_end > skb_tail_pointer(skb))
1182 have_auth = chunk_num;
1185 case SCTP_CID_COOKIE_ECHO:
1186 /* If a packet arrives containing an AUTH chunk as
1187 * a first chunk, a COOKIE-ECHO chunk as the second
1188 * chunk, and possibly more chunks after them, and
1189 * the receiver does not have an STCB for that
1190 * packet, then authentication is based on
1191 * the contents of the COOKIE- ECHO chunk.
1193 if (have_auth == 1 && chunk_num == 2)
1197 case SCTP_CID_ASCONF:
1198 if (have_auth || net->sctp.addip_noauth)
1199 asoc = __sctp_rcv_asconf_lookup(
1201 sctp_hdr(skb)->source,
1210 ch = (struct sctp_chunkhdr *)ch_end;
1212 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb));
1218 * There are circumstances when we need to look inside the SCTP packet
1219 * for information to help us find the association. Examples
1220 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1223 static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
1224 struct sk_buff *skb,
1225 const union sctp_addr *laddr,
1226 struct sctp_transport **transportp)
1228 struct sctp_chunkhdr *ch;
1230 /* We do not allow GSO frames here as we need to linearize and
1231 * then cannot guarantee frame boundaries. This shouldn't be an
1232 * issue as packets hitting this are mostly INIT or INIT-ACK and
1233 * those cannot be on GSO-style anyway.
1235 if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
1238 ch = (struct sctp_chunkhdr *)skb->data;
1240 /* The code below will attempt to walk the chunk and extract
1241 * parameter information. Before we do that, we need to verify
1242 * that the chunk length doesn't cause overflow. Otherwise, we'll
1245 if (SCTP_PAD4(ntohs(ch->length)) > skb->len)
1248 /* If this is INIT/INIT-ACK look inside the chunk too. */
1249 if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
1250 return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
1252 return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
1255 /* Lookup an association for an inbound skb. */
1256 static struct sctp_association *__sctp_rcv_lookup(struct net *net,
1257 struct sk_buff *skb,
1258 const union sctp_addr *paddr,
1259 const union sctp_addr *laddr,
1260 struct sctp_transport **transportp)
1262 struct sctp_association *asoc;
1264 asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
1268 /* Further lookup for INIT/INIT-ACK packets.
1269 * SCTP Implementors Guide, 2.18 Handling of address
1270 * parameters within the INIT or INIT-ACK.
1272 asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);
1276 if (paddr->sa.sa_family == AF_INET)
1277 pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n",
1278 &laddr->v4.sin_addr, ntohs(laddr->v4.sin_port),
1279 &paddr->v4.sin_addr, ntohs(paddr->v4.sin_port));
1281 pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n",
1282 &laddr->v6.sin6_addr, ntohs(laddr->v6.sin6_port),
1283 &paddr->v6.sin6_addr, ntohs(paddr->v6.sin6_port));