xref: /openbmc/linux/include/net/sctp/sctp.h (revision 3e26a691)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001-2003 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * The base lksctp header.
10  *
11  * This SCTP implementation is free software;
12  * you can redistribute it and/or modify it under the terms of
13  * the GNU General Public License as published by
14  * the Free Software Foundation; either version 2, or (at your option)
15  * any later version.
16  *
17  * This SCTP implementation is distributed in the hope that it
18  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
19  *                 ************************
20  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
21  * See the GNU General Public License for more details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with GNU CC; see the file COPYING.  If not, see
25  * <http://www.gnu.org/licenses/>.
26  *
27  * Please send any bug reports or fixes you make to the
28  * email address(es):
29  *    lksctp developers <linux-sctp@vger.kernel.org>
30  *
31  * Written or modified by:
32  *    La Monte H.P. Yarroll <piggy@acm.org>
33  *    Xingang Guo           <xingang.guo@intel.com>
34  *    Jon Grimm             <jgrimm@us.ibm.com>
35  *    Daisy Chang           <daisyc@us.ibm.com>
36  *    Sridhar Samudrala     <sri@us.ibm.com>
37  *    Ardelle Fan           <ardelle.fan@intel.com>
38  *    Ryan Layer            <rmlayer@us.ibm.com>
39  *    Kevin Gao             <kevin.gao@intel.com>
40  */
41 
42 #ifndef __net_sctp_h__
43 #define __net_sctp_h__
44 
45 /* Header Strategy.
46  *    Start getting some control over the header file depencies:
47  *       includes
48  *       constants
49  *       structs
50  *       prototypes
51  *       macros, externs, and inlines
52  *
53  *   Move test_frame specific items out of the kernel headers
54  *   and into the test frame headers.   This is not perfect in any sense
55  *   and will continue to evolve.
56  */
57 
58 #include <linux/types.h>
59 #include <linux/slab.h>
60 #include <linux/in.h>
61 #include <linux/tty.h>
62 #include <linux/proc_fs.h>
63 #include <linux/spinlock.h>
64 #include <linux/jiffies.h>
65 #include <linux/idr.h>
66 
67 #if IS_ENABLED(CONFIG_IPV6)
68 #include <net/ipv6.h>
69 #include <net/ip6_route.h>
70 #endif
71 
72 #include <asm/uaccess.h>
73 #include <asm/page.h>
74 #include <net/sock.h>
75 #include <net/snmp.h>
76 #include <net/sctp/structs.h>
77 #include <net/sctp/constants.h>
78 
79 #ifdef CONFIG_IP_SCTP_MODULE
80 #define SCTP_PROTOSW_FLAG 0
81 #else /* static! */
82 #define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
83 #endif
84 
85 /* Round an int up to the next multiple of 4.  */
86 #define WORD_ROUND(s) (((s)+3)&~3)
87 /* Truncate to the previous multiple of 4.  */
88 #define WORD_TRUNC(s) ((s)&~3)
89 
90 /*
91  * Function declarations.
92  */
93 
94 /*
95  * sctp/protocol.c
96  */
97 int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
98 			      sctp_scope_t, gfp_t gfp, int flags);
99 struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
100 int sctp_register_pf(struct sctp_pf *, sa_family_t);
101 void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
102 
103 /*
104  * sctp/socket.c
105  */
106 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
107 int sctp_inet_listen(struct socket *sock, int backlog);
108 void sctp_write_space(struct sock *sk);
109 void sctp_data_ready(struct sock *sk);
110 unsigned int sctp_poll(struct file *file, struct socket *sock,
111 		poll_table *wait);
112 void sctp_sock_rfree(struct sk_buff *skb);
113 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
114 		    struct sctp_association *asoc);
115 extern struct percpu_counter sctp_sockets_allocated;
116 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
117 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
118 
119 /*
120  * sctp/primitive.c
121  */
122 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
123 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
124 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
125 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
126 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
127 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
128 
129 /*
130  * sctp/input.c
131  */
132 int sctp_rcv(struct sk_buff *skb);
133 void sctp_v4_err(struct sk_buff *skb, u32 info);
134 void sctp_hash_endpoint(struct sctp_endpoint *);
135 void sctp_unhash_endpoint(struct sctp_endpoint *);
136 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
137 			     struct sctphdr *, struct sctp_association **,
138 			     struct sctp_transport **);
139 void sctp_err_finish(struct sock *, struct sctp_association *);
140 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
141 			   struct sctp_transport *t, __u32 pmtu);
142 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
143 			struct sk_buff *);
144 void sctp_icmp_proto_unreachable(struct sock *sk,
145 				 struct sctp_association *asoc,
146 				 struct sctp_transport *t);
147 void sctp_backlog_migrate(struct sctp_association *assoc,
148 			  struct sock *oldsk, struct sock *newsk);
149 int sctp_transport_hashtable_init(void);
150 void sctp_transport_hashtable_destroy(void);
151 void sctp_hash_transport(struct sctp_transport *t);
152 void sctp_unhash_transport(struct sctp_transport *t);
153 struct sctp_transport *sctp_addrs_lookup_transport(
154 				struct net *net,
155 				const union sctp_addr *laddr,
156 				const union sctp_addr *paddr);
157 struct sctp_transport *sctp_epaddr_lookup_transport(
158 				const struct sctp_endpoint *ep,
159 				const union sctp_addr *paddr);
160 
161 /*
162  * sctp/proc.c
163  */
164 int sctp_snmp_proc_init(struct net *net);
165 void sctp_snmp_proc_exit(struct net *net);
166 int sctp_eps_proc_init(struct net *net);
167 void sctp_eps_proc_exit(struct net *net);
168 int sctp_assocs_proc_init(struct net *net);
169 void sctp_assocs_proc_exit(struct net *net);
170 int sctp_remaddr_proc_init(struct net *net);
171 void sctp_remaddr_proc_exit(struct net *net);
172 
173 
174 /*
175  * Module global variables
176  */
177 
178  /*
179   * sctp/protocol.c
180   */
181 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
182 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
183 extern long sysctl_sctp_mem[3];
184 extern int sysctl_sctp_rmem[3];
185 extern int sysctl_sctp_wmem[3];
186 
187 /*
188  *  Section:  Macros, externs, and inlines
189  */
190 
191 /* SCTP SNMP MIB stats handlers */
192 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
193 #define SCTP_INC_STATS_BH(net, field)   SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
194 #define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
195 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
196 
197 /* sctp mib definitions */
198 enum {
199 	SCTP_MIB_NUM = 0,
200 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
201 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
202 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
203 	SCTP_MIB_ABORTEDS,			/* Aborteds */
204 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
205 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
206 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
207 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
208 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
209 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
210 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
211 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
212 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
213 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
214 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
215 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
216 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
217 	SCTP_MIB_T1_INIT_EXPIREDS,
218 	SCTP_MIB_T1_COOKIE_EXPIREDS,
219 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
220 	SCTP_MIB_T3_RTX_EXPIREDS,
221 	SCTP_MIB_T4_RTO_EXPIREDS,
222 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
223 	SCTP_MIB_DELAY_SACK_EXPIREDS,
224 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
225 	SCTP_MIB_T1_RETRANSMITS,
226 	SCTP_MIB_T3_RETRANSMITS,
227 	SCTP_MIB_PMTUD_RETRANSMITS,
228 	SCTP_MIB_FAST_RETRANSMITS,
229 	SCTP_MIB_IN_PKT_SOFTIRQ,
230 	SCTP_MIB_IN_PKT_BACKLOG,
231 	SCTP_MIB_IN_PKT_DISCARDS,
232 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
233 	__SCTP_MIB_MAX
234 };
235 
236 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
237 struct sctp_mib {
238         unsigned long   mibs[SCTP_MIB_MAX];
239 };
240 
241 /* helper function to track stats about max rto and related transport */
242 static inline void sctp_max_rto(struct sctp_association *asoc,
243 				struct sctp_transport *trans)
244 {
245 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
246 		asoc->stats.max_obs_rto = trans->rto;
247 		memset(&asoc->stats.obs_rto_ipaddr, 0,
248 			sizeof(struct sockaddr_storage));
249 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
250 			trans->af_specific->sockaddr_len);
251 	}
252 }
253 
254 /*
255  * Macros for keeping a global reference of object allocations.
256  */
257 #ifdef CONFIG_SCTP_DBG_OBJCNT
258 
259 extern atomic_t sctp_dbg_objcnt_sock;
260 extern atomic_t sctp_dbg_objcnt_ep;
261 extern atomic_t sctp_dbg_objcnt_assoc;
262 extern atomic_t sctp_dbg_objcnt_transport;
263 extern atomic_t sctp_dbg_objcnt_chunk;
264 extern atomic_t sctp_dbg_objcnt_bind_addr;
265 extern atomic_t sctp_dbg_objcnt_bind_bucket;
266 extern atomic_t sctp_dbg_objcnt_addr;
267 extern atomic_t sctp_dbg_objcnt_ssnmap;
268 extern atomic_t sctp_dbg_objcnt_datamsg;
269 extern atomic_t sctp_dbg_objcnt_keys;
270 
271 /* Macros to atomically increment/decrement objcnt counters.  */
272 #define SCTP_DBG_OBJCNT_INC(name) \
273 atomic_inc(&sctp_dbg_objcnt_## name)
274 #define SCTP_DBG_OBJCNT_DEC(name) \
275 atomic_dec(&sctp_dbg_objcnt_## name)
276 #define SCTP_DBG_OBJCNT(name) \
277 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
278 
279 /* Macro to help create new entries in in the global array of
280  * objcnt counters.
281  */
282 #define SCTP_DBG_OBJCNT_ENTRY(name) \
283 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
284 
285 void sctp_dbg_objcnt_init(struct net *);
286 void sctp_dbg_objcnt_exit(struct net *);
287 
288 #else
289 
290 #define SCTP_DBG_OBJCNT_INC(name)
291 #define SCTP_DBG_OBJCNT_DEC(name)
292 
293 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
294 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
295 
296 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
297 
298 #if defined CONFIG_SYSCTL
299 void sctp_sysctl_register(void);
300 void sctp_sysctl_unregister(void);
301 int sctp_sysctl_net_register(struct net *net);
302 void sctp_sysctl_net_unregister(struct net *net);
303 #else
304 static inline void sctp_sysctl_register(void) { return; }
305 static inline void sctp_sysctl_unregister(void) { return; }
306 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
307 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
308 #endif
309 
310 /* Size of Supported Address Parameter for 'x' address types. */
311 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
312 
313 #if IS_ENABLED(CONFIG_IPV6)
314 
315 void sctp_v6_pf_init(void);
316 void sctp_v6_pf_exit(void);
317 int sctp_v6_protosw_init(void);
318 void sctp_v6_protosw_exit(void);
319 int sctp_v6_add_protocol(void);
320 void sctp_v6_del_protocol(void);
321 
322 #else /* #ifdef defined(CONFIG_IPV6) */
323 
324 static inline void sctp_v6_pf_init(void) { return; }
325 static inline void sctp_v6_pf_exit(void) { return; }
326 static inline int sctp_v6_protosw_init(void) { return 0; }
327 static inline void sctp_v6_protosw_exit(void) { return; }
328 static inline int sctp_v6_add_protocol(void) { return 0; }
329 static inline void sctp_v6_del_protocol(void) { return; }
330 
331 #endif /* #if defined(CONFIG_IPV6) */
332 
333 
334 /* Map an association to an assoc_id. */
335 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
336 {
337 	return asoc ? asoc->assoc_id : 0;
338 }
339 
340 static inline enum sctp_sstat_state
341 sctp_assoc_to_state(const struct sctp_association *asoc)
342 {
343 	/* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
344 	 * got rid of it in kernel space. Therefore SCTP_CLOSED et al
345 	 * start at =1 in user space, but actually as =0 in kernel space.
346 	 * Now that we can not break user space and SCTP_EMPTY is exposed
347 	 * there, we need to fix it up with an ugly offset not to break
348 	 * applications. :(
349 	 */
350 	return asoc->state + 1;
351 }
352 
353 /* Look up the association by its id.  */
354 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
355 
356 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
357 
358 /* A macro to walk a list of skbs.  */
359 #define sctp_skb_for_each(pos, head, tmp) \
360 	skb_queue_walk_safe(head, pos, tmp)
361 
362 /* A helper to append an entire skb list (list) to another (head). */
363 static inline void sctp_skb_list_tail(struct sk_buff_head *list,
364 				      struct sk_buff_head *head)
365 {
366 	unsigned long flags;
367 
368 	spin_lock_irqsave(&head->lock, flags);
369 	spin_lock(&list->lock);
370 
371 	skb_queue_splice_tail_init(list, head);
372 
373 	spin_unlock(&list->lock);
374 	spin_unlock_irqrestore(&head->lock, flags);
375 }
376 
377 /**
378  *	sctp_list_dequeue - remove from the head of the queue
379  *	@list: list to dequeue from
380  *
381  *	Remove the head of the list. The head item is
382  *	returned or %NULL if the list is empty.
383  */
384 
385 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
386 {
387 	struct list_head *result = NULL;
388 
389 	if (list->next != list) {
390 		result = list->next;
391 		list->next = result->next;
392 		list->next->prev = list;
393 		INIT_LIST_HEAD(result);
394 	}
395 	return result;
396 }
397 
398 /* SCTP version of skb_set_owner_r.  We need this one because
399  * of the way we have to do receive buffer accounting on bundled
400  * chunks.
401  */
402 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
403 {
404 	struct sctp_ulpevent *event = sctp_skb2event(skb);
405 
406 	skb_orphan(skb);
407 	skb->sk = sk;
408 	skb->destructor = sctp_sock_rfree;
409 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
410 	/*
411 	 * This mimics the behavior of skb_set_owner_r
412 	 */
413 	sk->sk_forward_alloc -= event->rmem_len;
414 }
415 
416 /* Tests if the list has one and only one entry. */
417 static inline int sctp_list_single_entry(struct list_head *head)
418 {
419 	return (head->next != head) && (head->next == head->prev);
420 }
421 
422 /* Break down data chunks at this point.  */
423 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
424 {
425 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
426 	int frag = pmtu;
427 
428 	frag -= sp->pf->af->net_header_len;
429 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
430 
431 	if (asoc->user_frag)
432 		frag = min_t(int, frag, asoc->user_frag);
433 
434 	frag = WORD_TRUNC(min_t(int, frag, SCTP_MAX_CHUNK_LEN));
435 
436 	return frag;
437 }
438 
439 static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
440 {
441 
442 	sctp_assoc_sync_pmtu(sk, asoc);
443 	asoc->pmtu_pending = 0;
444 }
445 
446 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
447 {
448 	return !list_empty(&chunk->list);
449 }
450 
451 /* Walk through a list of TLV parameters.  Don't trust the
452  * individual parameter lengths and instead depend on
453  * the chunk length to indicate when to stop.  Make sure
454  * there is room for a param header too.
455  */
456 #define sctp_walk_params(pos, chunk, member)\
457 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
458 
459 #define _sctp_walk_params(pos, chunk, end, member)\
460 for (pos.v = chunk->member;\
461      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
462      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
463      pos.v += WORD_ROUND(ntohs(pos.p->length)))
464 
465 #define sctp_walk_errors(err, chunk_hdr)\
466 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
467 
468 #define _sctp_walk_errors(err, chunk_hdr, end)\
469 for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
470 	    sizeof(sctp_chunkhdr_t));\
471      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
472      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
473      err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
474 
475 #define sctp_walk_fwdtsn(pos, chunk)\
476 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
477 
478 #define _sctp_walk_fwdtsn(pos, chunk, end)\
479 for (pos = chunk->subh.fwdtsn_hdr->skip;\
480      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
481      pos++)
482 
483 /* External references. */
484 
485 extern struct proto sctp_prot;
486 extern struct proto sctpv6_prot;
487 void sctp_put_port(struct sock *sk);
488 
489 extern struct idr sctp_assocs_id;
490 extern spinlock_t sctp_assocs_id_lock;
491 
492 /* Static inline functions. */
493 
494 /* Convert from an IP version number to an Address Family symbol.  */
495 static inline int ipver2af(__u8 ipver)
496 {
497 	switch (ipver) {
498 	case 4:
499 	        return  AF_INET;
500 	case 6:
501 		return AF_INET6;
502 	default:
503 		return 0;
504 	}
505 }
506 
507 /* Convert from an address parameter type to an address family.  */
508 static inline int param_type2af(__be16 type)
509 {
510 	switch (type) {
511 	case SCTP_PARAM_IPV4_ADDRESS:
512 	        return  AF_INET;
513 	case SCTP_PARAM_IPV6_ADDRESS:
514 		return AF_INET6;
515 	default:
516 		return 0;
517 	}
518 }
519 
520 /* Warning: The following hash functions assume a power of two 'size'. */
521 /* This is the hash function for the SCTP port hash table. */
522 static inline int sctp_phashfn(struct net *net, __u16 lport)
523 {
524 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
525 }
526 
527 /* This is the hash function for the endpoint hash table. */
528 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
529 {
530 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
531 }
532 
533 #define sctp_for_each_hentry(epb, head) \
534 	hlist_for_each_entry(epb, head, node)
535 
536 /* Is a socket of this style? */
537 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
538 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
539 {
540 	return sctp_sk(sk)->type == style;
541 }
542 
543 /* Is the association in this state? */
544 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
545 static inline int __sctp_state(const struct sctp_association *asoc,
546 			       sctp_state_t state)
547 {
548 	return asoc->state == state;
549 }
550 
551 /* Is the socket in this state? */
552 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
553 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
554 {
555 	return sk->sk_state == state;
556 }
557 
558 /* Map v4-mapped v6 address back to v4 address */
559 static inline void sctp_v6_map_v4(union sctp_addr *addr)
560 {
561 	addr->v4.sin_family = AF_INET;
562 	addr->v4.sin_port = addr->v6.sin6_port;
563 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
564 }
565 
566 /* Map v4 address to v4-mapped v6 address */
567 static inline void sctp_v4_map_v6(union sctp_addr *addr)
568 {
569 	__be16 port;
570 
571 	port = addr->v4.sin_port;
572 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
573 	addr->v6.sin6_port = port;
574 	addr->v6.sin6_family = AF_INET6;
575 	addr->v6.sin6_flowinfo = 0;
576 	addr->v6.sin6_scope_id = 0;
577 	addr->v6.sin6_addr.s6_addr32[0] = 0;
578 	addr->v6.sin6_addr.s6_addr32[1] = 0;
579 	addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
580 }
581 
582 /* The cookie is always 0 since this is how it's used in the
583  * pmtu code.
584  */
585 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
586 {
587 	if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
588 		dst_release(t->dst);
589 		t->dst = NULL;
590 	}
591 
592 	return t->dst;
593 }
594 
595 #endif /* __net_sctp_h__ */
596