xref: /openbmc/linux/include/net/sctp/sctp.h (revision 8730046c)
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 <linux/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 SCTP_PAD4(s) (((s)+3)&~3)
87 /* Truncate to the previous multiple of 4.  */
88 #define SCTP_TRUNC4(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 int sctp_transport_walk_start(struct rhashtable_iter *iter);
120 void sctp_transport_walk_stop(struct rhashtable_iter *iter);
121 struct sctp_transport *sctp_transport_get_next(struct net *net,
122 			struct rhashtable_iter *iter);
123 struct sctp_transport *sctp_transport_get_idx(struct net *net,
124 			struct rhashtable_iter *iter, int pos);
125 int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
126 				  struct net *net,
127 				  const union sctp_addr *laddr,
128 				  const union sctp_addr *paddr, void *p);
129 int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
130 			    struct net *net, int pos, void *p);
131 int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p);
132 int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
133 		       struct sctp_info *info);
134 
135 /*
136  * sctp/primitive.c
137  */
138 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
139 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
140 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
141 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
142 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
143 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
144 
145 /*
146  * sctp/input.c
147  */
148 int sctp_rcv(struct sk_buff *skb);
149 void sctp_v4_err(struct sk_buff *skb, u32 info);
150 void sctp_hash_endpoint(struct sctp_endpoint *);
151 void sctp_unhash_endpoint(struct sctp_endpoint *);
152 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
153 			     struct sctphdr *, struct sctp_association **,
154 			     struct sctp_transport **);
155 void sctp_err_finish(struct sock *, struct sctp_transport *);
156 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
157 			   struct sctp_transport *t, __u32 pmtu);
158 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
159 			struct sk_buff *);
160 void sctp_icmp_proto_unreachable(struct sock *sk,
161 				 struct sctp_association *asoc,
162 				 struct sctp_transport *t);
163 void sctp_backlog_migrate(struct sctp_association *assoc,
164 			  struct sock *oldsk, struct sock *newsk);
165 int sctp_transport_hashtable_init(void);
166 void sctp_transport_hashtable_destroy(void);
167 int sctp_hash_transport(struct sctp_transport *t);
168 void sctp_unhash_transport(struct sctp_transport *t);
169 struct sctp_transport *sctp_addrs_lookup_transport(
170 				struct net *net,
171 				const union sctp_addr *laddr,
172 				const union sctp_addr *paddr);
173 struct sctp_transport *sctp_epaddr_lookup_transport(
174 				const struct sctp_endpoint *ep,
175 				const union sctp_addr *paddr);
176 
177 /*
178  * sctp/proc.c
179  */
180 int sctp_snmp_proc_init(struct net *net);
181 void sctp_snmp_proc_exit(struct net *net);
182 int sctp_eps_proc_init(struct net *net);
183 void sctp_eps_proc_exit(struct net *net);
184 int sctp_assocs_proc_init(struct net *net);
185 void sctp_assocs_proc_exit(struct net *net);
186 int sctp_remaddr_proc_init(struct net *net);
187 void sctp_remaddr_proc_exit(struct net *net);
188 
189 /*
190  * sctp/offload.c
191  */
192 int sctp_offload_init(void);
193 
194 /*
195  * Module global variables
196  */
197 
198  /*
199   * sctp/protocol.c
200   */
201 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
202 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
203 extern long sysctl_sctp_mem[3];
204 extern int sysctl_sctp_rmem[3];
205 extern int sysctl_sctp_wmem[3];
206 
207 /*
208  *  Section:  Macros, externs, and inlines
209  */
210 
211 /* SCTP SNMP MIB stats handlers */
212 #define SCTP_INC_STATS(net, field)	SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
213 #define __SCTP_INC_STATS(net, field)	__SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
214 #define SCTP_DEC_STATS(net, field)	SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
215 
216 /* sctp mib definitions */
217 enum {
218 	SCTP_MIB_NUM = 0,
219 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
220 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
221 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
222 	SCTP_MIB_ABORTEDS,			/* Aborteds */
223 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
224 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
225 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
226 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
227 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
228 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
229 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
230 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
231 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
232 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
233 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
234 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
235 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
236 	SCTP_MIB_T1_INIT_EXPIREDS,
237 	SCTP_MIB_T1_COOKIE_EXPIREDS,
238 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
239 	SCTP_MIB_T3_RTX_EXPIREDS,
240 	SCTP_MIB_T4_RTO_EXPIREDS,
241 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
242 	SCTP_MIB_DELAY_SACK_EXPIREDS,
243 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
244 	SCTP_MIB_T1_RETRANSMITS,
245 	SCTP_MIB_T3_RETRANSMITS,
246 	SCTP_MIB_PMTUD_RETRANSMITS,
247 	SCTP_MIB_FAST_RETRANSMITS,
248 	SCTP_MIB_IN_PKT_SOFTIRQ,
249 	SCTP_MIB_IN_PKT_BACKLOG,
250 	SCTP_MIB_IN_PKT_DISCARDS,
251 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
252 	__SCTP_MIB_MAX
253 };
254 
255 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
256 struct sctp_mib {
257         unsigned long   mibs[SCTP_MIB_MAX];
258 };
259 
260 /* helper function to track stats about max rto and related transport */
261 static inline void sctp_max_rto(struct sctp_association *asoc,
262 				struct sctp_transport *trans)
263 {
264 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
265 		asoc->stats.max_obs_rto = trans->rto;
266 		memset(&asoc->stats.obs_rto_ipaddr, 0,
267 			sizeof(struct sockaddr_storage));
268 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
269 			trans->af_specific->sockaddr_len);
270 	}
271 }
272 
273 /*
274  * Macros for keeping a global reference of object allocations.
275  */
276 #ifdef CONFIG_SCTP_DBG_OBJCNT
277 
278 extern atomic_t sctp_dbg_objcnt_sock;
279 extern atomic_t sctp_dbg_objcnt_ep;
280 extern atomic_t sctp_dbg_objcnt_assoc;
281 extern atomic_t sctp_dbg_objcnt_transport;
282 extern atomic_t sctp_dbg_objcnt_chunk;
283 extern atomic_t sctp_dbg_objcnt_bind_addr;
284 extern atomic_t sctp_dbg_objcnt_bind_bucket;
285 extern atomic_t sctp_dbg_objcnt_addr;
286 extern atomic_t sctp_dbg_objcnt_ssnmap;
287 extern atomic_t sctp_dbg_objcnt_datamsg;
288 extern atomic_t sctp_dbg_objcnt_keys;
289 
290 /* Macros to atomically increment/decrement objcnt counters.  */
291 #define SCTP_DBG_OBJCNT_INC(name) \
292 atomic_inc(&sctp_dbg_objcnt_## name)
293 #define SCTP_DBG_OBJCNT_DEC(name) \
294 atomic_dec(&sctp_dbg_objcnt_## name)
295 #define SCTP_DBG_OBJCNT(name) \
296 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
297 
298 /* Macro to help create new entries in in the global array of
299  * objcnt counters.
300  */
301 #define SCTP_DBG_OBJCNT_ENTRY(name) \
302 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
303 
304 void sctp_dbg_objcnt_init(struct net *);
305 void sctp_dbg_objcnt_exit(struct net *);
306 
307 #else
308 
309 #define SCTP_DBG_OBJCNT_INC(name)
310 #define SCTP_DBG_OBJCNT_DEC(name)
311 
312 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
313 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
314 
315 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
316 
317 #if defined CONFIG_SYSCTL
318 void sctp_sysctl_register(void);
319 void sctp_sysctl_unregister(void);
320 int sctp_sysctl_net_register(struct net *net);
321 void sctp_sysctl_net_unregister(struct net *net);
322 #else
323 static inline void sctp_sysctl_register(void) { return; }
324 static inline void sctp_sysctl_unregister(void) { return; }
325 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
326 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
327 #endif
328 
329 /* Size of Supported Address Parameter for 'x' address types. */
330 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
331 
332 #if IS_ENABLED(CONFIG_IPV6)
333 
334 void sctp_v6_pf_init(void);
335 void sctp_v6_pf_exit(void);
336 int sctp_v6_protosw_init(void);
337 void sctp_v6_protosw_exit(void);
338 int sctp_v6_add_protocol(void);
339 void sctp_v6_del_protocol(void);
340 
341 #else /* #ifdef defined(CONFIG_IPV6) */
342 
343 static inline void sctp_v6_pf_init(void) { return; }
344 static inline void sctp_v6_pf_exit(void) { return; }
345 static inline int sctp_v6_protosw_init(void) { return 0; }
346 static inline void sctp_v6_protosw_exit(void) { return; }
347 static inline int sctp_v6_add_protocol(void) { return 0; }
348 static inline void sctp_v6_del_protocol(void) { return; }
349 
350 #endif /* #if defined(CONFIG_IPV6) */
351 
352 
353 /* Map an association to an assoc_id. */
354 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
355 {
356 	return asoc ? asoc->assoc_id : 0;
357 }
358 
359 static inline enum sctp_sstat_state
360 sctp_assoc_to_state(const struct sctp_association *asoc)
361 {
362 	/* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
363 	 * got rid of it in kernel space. Therefore SCTP_CLOSED et al
364 	 * start at =1 in user space, but actually as =0 in kernel space.
365 	 * Now that we can not break user space and SCTP_EMPTY is exposed
366 	 * there, we need to fix it up with an ugly offset not to break
367 	 * applications. :(
368 	 */
369 	return asoc->state + 1;
370 }
371 
372 /* Look up the association by its id.  */
373 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
374 
375 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
376 
377 /* A macro to walk a list of skbs.  */
378 #define sctp_skb_for_each(pos, head, tmp) \
379 	skb_queue_walk_safe(head, pos, tmp)
380 
381 /**
382  *	sctp_list_dequeue - remove from the head of the queue
383  *	@list: list to dequeue from
384  *
385  *	Remove the head of the list. The head item is
386  *	returned or %NULL if the list is empty.
387  */
388 
389 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
390 {
391 	struct list_head *result = NULL;
392 
393 	if (!list_empty(list)) {
394 		result = list->next;
395 		list_del_init(result);
396 	}
397 	return result;
398 }
399 
400 /* SCTP version of skb_set_owner_r.  We need this one because
401  * of the way we have to do receive buffer accounting on bundled
402  * chunks.
403  */
404 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
405 {
406 	struct sctp_ulpevent *event = sctp_skb2event(skb);
407 
408 	skb_orphan(skb);
409 	skb->sk = sk;
410 	skb->destructor = sctp_sock_rfree;
411 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
412 	/*
413 	 * This mimics the behavior of skb_set_owner_r
414 	 */
415 	sk->sk_forward_alloc -= event->rmem_len;
416 }
417 
418 /* Tests if the list has one and only one entry. */
419 static inline int sctp_list_single_entry(struct list_head *head)
420 {
421 	return (head->next != head) && (head->next == head->prev);
422 }
423 
424 /* Break down data chunks at this point.  */
425 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
426 {
427 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
428 	int frag = pmtu;
429 
430 	frag -= sp->pf->af->net_header_len;
431 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
432 
433 	if (asoc->user_frag)
434 		frag = min_t(int, frag, asoc->user_frag);
435 
436 	frag = SCTP_TRUNC4(min_t(int, frag, SCTP_MAX_CHUNK_LEN));
437 
438 	return frag;
439 }
440 
441 static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
442 {
443 
444 	sctp_assoc_sync_pmtu(sk, asoc);
445 	asoc->pmtu_pending = 0;
446 }
447 
448 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
449 {
450 	return !list_empty(&chunk->list);
451 }
452 
453 /* Walk through a list of TLV parameters.  Don't trust the
454  * individual parameter lengths and instead depend on
455  * the chunk length to indicate when to stop.  Make sure
456  * there is room for a param header too.
457  */
458 #define sctp_walk_params(pos, chunk, member)\
459 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
460 
461 #define _sctp_walk_params(pos, chunk, end, member)\
462 for (pos.v = chunk->member;\
463      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
464      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
465      pos.v += SCTP_PAD4(ntohs(pos.p->length)))
466 
467 #define sctp_walk_errors(err, chunk_hdr)\
468 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
469 
470 #define _sctp_walk_errors(err, chunk_hdr, end)\
471 for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
472 	    sizeof(sctp_chunkhdr_t));\
473      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
474      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
475      err = (sctp_errhdr_t *)((void *)err + SCTP_PAD4(ntohs(err->length))))
476 
477 #define sctp_walk_fwdtsn(pos, chunk)\
478 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
479 
480 #define _sctp_walk_fwdtsn(pos, chunk, end)\
481 for (pos = chunk->subh.fwdtsn_hdr->skip;\
482      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
483      pos++)
484 
485 /* External references. */
486 
487 extern struct proto sctp_prot;
488 extern struct proto sctpv6_prot;
489 void sctp_put_port(struct sock *sk);
490 
491 extern struct idr sctp_assocs_id;
492 extern spinlock_t sctp_assocs_id_lock;
493 
494 /* Static inline functions. */
495 
496 /* Convert from an IP version number to an Address Family symbol.  */
497 static inline int ipver2af(__u8 ipver)
498 {
499 	switch (ipver) {
500 	case 4:
501 	        return  AF_INET;
502 	case 6:
503 		return AF_INET6;
504 	default:
505 		return 0;
506 	}
507 }
508 
509 /* Convert from an address parameter type to an address family.  */
510 static inline int param_type2af(__be16 type)
511 {
512 	switch (type) {
513 	case SCTP_PARAM_IPV4_ADDRESS:
514 	        return  AF_INET;
515 	case SCTP_PARAM_IPV6_ADDRESS:
516 		return AF_INET6;
517 	default:
518 		return 0;
519 	}
520 }
521 
522 /* Warning: The following hash functions assume a power of two 'size'. */
523 /* This is the hash function for the SCTP port hash table. */
524 static inline int sctp_phashfn(struct net *net, __u16 lport)
525 {
526 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
527 }
528 
529 /* This is the hash function for the endpoint hash table. */
530 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
531 {
532 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
533 }
534 
535 #define sctp_for_each_hentry(epb, head) \
536 	hlist_for_each_entry(epb, head, node)
537 
538 /* Is a socket of this style? */
539 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
540 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
541 {
542 	return sctp_sk(sk)->type == style;
543 }
544 
545 /* Is the association in this state? */
546 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
547 static inline int __sctp_state(const struct sctp_association *asoc,
548 			       sctp_state_t state)
549 {
550 	return asoc->state == state;
551 }
552 
553 /* Is the socket in this state? */
554 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
555 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
556 {
557 	return sk->sk_state == state;
558 }
559 
560 /* Map v4-mapped v6 address back to v4 address */
561 static inline void sctp_v6_map_v4(union sctp_addr *addr)
562 {
563 	addr->v4.sin_family = AF_INET;
564 	addr->v4.sin_port = addr->v6.sin6_port;
565 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
566 }
567 
568 /* Map v4 address to v4-mapped v6 address */
569 static inline void sctp_v4_map_v6(union sctp_addr *addr)
570 {
571 	__be16 port;
572 
573 	port = addr->v4.sin_port;
574 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
575 	addr->v6.sin6_port = port;
576 	addr->v6.sin6_family = AF_INET6;
577 	addr->v6.sin6_flowinfo = 0;
578 	addr->v6.sin6_scope_id = 0;
579 	addr->v6.sin6_addr.s6_addr32[0] = 0;
580 	addr->v6.sin6_addr.s6_addr32[1] = 0;
581 	addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
582 }
583 
584 /* The cookie is always 0 since this is how it's used in the
585  * pmtu code.
586  */
587 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
588 {
589 	if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
590 		dst_release(t->dst);
591 		t->dst = NULL;
592 	}
593 
594 	return t->dst;
595 }
596 
597 #endif /* __net_sctp_h__ */
598