xref: /openbmc/linux/include/net/sctp/sctp.h (revision 93d90ad7)
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 /*
86  * Function declarations.
87  */
88 
89 /*
90  * sctp/protocol.c
91  */
92 int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
93 			      sctp_scope_t, gfp_t gfp, int flags);
94 struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
95 int sctp_register_pf(struct sctp_pf *, sa_family_t);
96 void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
97 
98 /*
99  * sctp/socket.c
100  */
101 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
102 int sctp_inet_listen(struct socket *sock, int backlog);
103 void sctp_write_space(struct sock *sk);
104 void sctp_data_ready(struct sock *sk);
105 unsigned int sctp_poll(struct file *file, struct socket *sock,
106 		poll_table *wait);
107 void sctp_sock_rfree(struct sk_buff *skb);
108 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
109 		    struct sctp_association *asoc);
110 extern struct percpu_counter sctp_sockets_allocated;
111 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
112 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
113 
114 /*
115  * sctp/primitive.c
116  */
117 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
118 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
119 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
120 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
121 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
122 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
123 
124 /*
125  * sctp/input.c
126  */
127 int sctp_rcv(struct sk_buff *skb);
128 void sctp_v4_err(struct sk_buff *skb, u32 info);
129 void sctp_hash_established(struct sctp_association *);
130 void sctp_unhash_established(struct sctp_association *);
131 void sctp_hash_endpoint(struct sctp_endpoint *);
132 void sctp_unhash_endpoint(struct sctp_endpoint *);
133 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
134 			     struct sctphdr *, struct sctp_association **,
135 			     struct sctp_transport **);
136 void sctp_err_finish(struct sock *, struct sctp_association *);
137 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
138 			   struct sctp_transport *t, __u32 pmtu);
139 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
140 			struct sk_buff *);
141 void sctp_icmp_proto_unreachable(struct sock *sk,
142 				 struct sctp_association *asoc,
143 				 struct sctp_transport *t);
144 void sctp_backlog_migrate(struct sctp_association *assoc,
145 			  struct sock *oldsk, struct sock *newsk);
146 
147 /*
148  * sctp/proc.c
149  */
150 int sctp_snmp_proc_init(struct net *net);
151 void sctp_snmp_proc_exit(struct net *net);
152 int sctp_eps_proc_init(struct net *net);
153 void sctp_eps_proc_exit(struct net *net);
154 int sctp_assocs_proc_init(struct net *net);
155 void sctp_assocs_proc_exit(struct net *net);
156 int sctp_remaddr_proc_init(struct net *net);
157 void sctp_remaddr_proc_exit(struct net *net);
158 
159 
160 /*
161  * Module global variables
162  */
163 
164  /*
165   * sctp/protocol.c
166   */
167 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
168 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
169 
170 /*
171  *  Section:  Macros, externs, and inlines
172  */
173 
174 /* SCTP SNMP MIB stats handlers */
175 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
176 #define SCTP_INC_STATS_BH(net, field)   SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
177 #define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
178 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
179 
180 /* sctp mib definitions */
181 enum {
182 	SCTP_MIB_NUM = 0,
183 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
184 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
185 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
186 	SCTP_MIB_ABORTEDS,			/* Aborteds */
187 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
188 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
189 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
190 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
191 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
192 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
193 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
194 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
195 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
196 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
197 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
198 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
199 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
200 	SCTP_MIB_T1_INIT_EXPIREDS,
201 	SCTP_MIB_T1_COOKIE_EXPIREDS,
202 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
203 	SCTP_MIB_T3_RTX_EXPIREDS,
204 	SCTP_MIB_T4_RTO_EXPIREDS,
205 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
206 	SCTP_MIB_DELAY_SACK_EXPIREDS,
207 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
208 	SCTP_MIB_T1_RETRANSMITS,
209 	SCTP_MIB_T3_RETRANSMITS,
210 	SCTP_MIB_PMTUD_RETRANSMITS,
211 	SCTP_MIB_FAST_RETRANSMITS,
212 	SCTP_MIB_IN_PKT_SOFTIRQ,
213 	SCTP_MIB_IN_PKT_BACKLOG,
214 	SCTP_MIB_IN_PKT_DISCARDS,
215 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
216 	__SCTP_MIB_MAX
217 };
218 
219 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
220 struct sctp_mib {
221         unsigned long   mibs[SCTP_MIB_MAX];
222 };
223 
224 /* helper function to track stats about max rto and related transport */
225 static inline void sctp_max_rto(struct sctp_association *asoc,
226 				struct sctp_transport *trans)
227 {
228 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
229 		asoc->stats.max_obs_rto = trans->rto;
230 		memset(&asoc->stats.obs_rto_ipaddr, 0,
231 			sizeof(struct sockaddr_storage));
232 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
233 			trans->af_specific->sockaddr_len);
234 	}
235 }
236 
237 /*
238  * Macros for keeping a global reference of object allocations.
239  */
240 #ifdef CONFIG_SCTP_DBG_OBJCNT
241 
242 extern atomic_t sctp_dbg_objcnt_sock;
243 extern atomic_t sctp_dbg_objcnt_ep;
244 extern atomic_t sctp_dbg_objcnt_assoc;
245 extern atomic_t sctp_dbg_objcnt_transport;
246 extern atomic_t sctp_dbg_objcnt_chunk;
247 extern atomic_t sctp_dbg_objcnt_bind_addr;
248 extern atomic_t sctp_dbg_objcnt_bind_bucket;
249 extern atomic_t sctp_dbg_objcnt_addr;
250 extern atomic_t sctp_dbg_objcnt_ssnmap;
251 extern atomic_t sctp_dbg_objcnt_datamsg;
252 extern atomic_t sctp_dbg_objcnt_keys;
253 
254 /* Macros to atomically increment/decrement objcnt counters.  */
255 #define SCTP_DBG_OBJCNT_INC(name) \
256 atomic_inc(&sctp_dbg_objcnt_## name)
257 #define SCTP_DBG_OBJCNT_DEC(name) \
258 atomic_dec(&sctp_dbg_objcnt_## name)
259 #define SCTP_DBG_OBJCNT(name) \
260 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
261 
262 /* Macro to help create new entries in in the global array of
263  * objcnt counters.
264  */
265 #define SCTP_DBG_OBJCNT_ENTRY(name) \
266 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
267 
268 void sctp_dbg_objcnt_init(struct net *);
269 void sctp_dbg_objcnt_exit(struct net *);
270 
271 #else
272 
273 #define SCTP_DBG_OBJCNT_INC(name)
274 #define SCTP_DBG_OBJCNT_DEC(name)
275 
276 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
277 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
278 
279 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
280 
281 #if defined CONFIG_SYSCTL
282 void sctp_sysctl_register(void);
283 void sctp_sysctl_unregister(void);
284 int sctp_sysctl_net_register(struct net *net);
285 void sctp_sysctl_net_unregister(struct net *net);
286 #else
287 static inline void sctp_sysctl_register(void) { return; }
288 static inline void sctp_sysctl_unregister(void) { return; }
289 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
290 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
291 #endif
292 
293 /* Size of Supported Address Parameter for 'x' address types. */
294 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
295 
296 #if IS_ENABLED(CONFIG_IPV6)
297 
298 void sctp_v6_pf_init(void);
299 void sctp_v6_pf_exit(void);
300 int sctp_v6_protosw_init(void);
301 void sctp_v6_protosw_exit(void);
302 int sctp_v6_add_protocol(void);
303 void sctp_v6_del_protocol(void);
304 
305 #else /* #ifdef defined(CONFIG_IPV6) */
306 
307 static inline void sctp_v6_pf_init(void) { return; }
308 static inline void sctp_v6_pf_exit(void) { return; }
309 static inline int sctp_v6_protosw_init(void) { return 0; }
310 static inline void sctp_v6_protosw_exit(void) { return; }
311 static inline int sctp_v6_add_protocol(void) { return 0; }
312 static inline void sctp_v6_del_protocol(void) { return; }
313 
314 #endif /* #if defined(CONFIG_IPV6) */
315 
316 
317 /* Map an association to an assoc_id. */
318 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
319 {
320 	return asoc ? asoc->assoc_id : 0;
321 }
322 
323 static inline enum sctp_sstat_state
324 sctp_assoc_to_state(const struct sctp_association *asoc)
325 {
326 	/* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
327 	 * got rid of it in kernel space. Therefore SCTP_CLOSED et al
328 	 * start at =1 in user space, but actually as =0 in kernel space.
329 	 * Now that we can not break user space and SCTP_EMPTY is exposed
330 	 * there, we need to fix it up with an ugly offset not to break
331 	 * applications. :(
332 	 */
333 	return asoc->state + 1;
334 }
335 
336 /* Look up the association by its id.  */
337 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
338 
339 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
340 
341 /* A macro to walk a list of skbs.  */
342 #define sctp_skb_for_each(pos, head, tmp) \
343 	skb_queue_walk_safe(head, pos, tmp)
344 
345 /* A helper to append an entire skb list (list) to another (head). */
346 static inline void sctp_skb_list_tail(struct sk_buff_head *list,
347 				      struct sk_buff_head *head)
348 {
349 	unsigned long flags;
350 
351 	spin_lock_irqsave(&head->lock, flags);
352 	spin_lock(&list->lock);
353 
354 	skb_queue_splice_tail_init(list, head);
355 
356 	spin_unlock(&list->lock);
357 	spin_unlock_irqrestore(&head->lock, flags);
358 }
359 
360 /**
361  *	sctp_list_dequeue - remove from the head of the queue
362  *	@list: list to dequeue from
363  *
364  *	Remove the head of the list. The head item is
365  *	returned or %NULL if the list is empty.
366  */
367 
368 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
369 {
370 	struct list_head *result = NULL;
371 
372 	if (list->next != list) {
373 		result = list->next;
374 		list->next = result->next;
375 		list->next->prev = list;
376 		INIT_LIST_HEAD(result);
377 	}
378 	return result;
379 }
380 
381 /* SCTP version of skb_set_owner_r.  We need this one because
382  * of the way we have to do receive buffer accounting on bundled
383  * chunks.
384  */
385 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
386 {
387 	struct sctp_ulpevent *event = sctp_skb2event(skb);
388 
389 	skb_orphan(skb);
390 	skb->sk = sk;
391 	skb->destructor = sctp_sock_rfree;
392 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
393 	/*
394 	 * This mimics the behavior of skb_set_owner_r
395 	 */
396 	sk->sk_forward_alloc -= event->rmem_len;
397 }
398 
399 /* Tests if the list has one and only one entry. */
400 static inline int sctp_list_single_entry(struct list_head *head)
401 {
402 	return (head->next != head) && (head->next == head->prev);
403 }
404 
405 /* Break down data chunks at this point.  */
406 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
407 {
408 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
409 	int frag = pmtu;
410 
411 	frag -= sp->pf->af->net_header_len;
412 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
413 
414 	if (asoc->user_frag)
415 		frag = min_t(int, frag, asoc->user_frag);
416 
417 	frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);
418 
419 	return frag;
420 }
421 
422 static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
423 {
424 
425 	sctp_assoc_sync_pmtu(sk, asoc);
426 	asoc->pmtu_pending = 0;
427 }
428 
429 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
430 {
431 	return !list_empty(&chunk->list);
432 }
433 
434 /* Walk through a list of TLV parameters.  Don't trust the
435  * individual parameter lengths and instead depend on
436  * the chunk length to indicate when to stop.  Make sure
437  * there is room for a param header too.
438  */
439 #define sctp_walk_params(pos, chunk, member)\
440 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
441 
442 #define _sctp_walk_params(pos, chunk, end, member)\
443 for (pos.v = chunk->member;\
444      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
445      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
446      pos.v += WORD_ROUND(ntohs(pos.p->length)))
447 
448 #define sctp_walk_errors(err, chunk_hdr)\
449 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
450 
451 #define _sctp_walk_errors(err, chunk_hdr, end)\
452 for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
453 	    sizeof(sctp_chunkhdr_t));\
454      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
455      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
456      err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
457 
458 #define sctp_walk_fwdtsn(pos, chunk)\
459 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
460 
461 #define _sctp_walk_fwdtsn(pos, chunk, end)\
462 for (pos = chunk->subh.fwdtsn_hdr->skip;\
463      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
464      pos++)
465 
466 /* Round an int up to the next multiple of 4.  */
467 #define WORD_ROUND(s) (((s)+3)&~3)
468 
469 /* External references. */
470 
471 extern struct proto sctp_prot;
472 extern struct proto sctpv6_prot;
473 void sctp_put_port(struct sock *sk);
474 
475 extern struct idr sctp_assocs_id;
476 extern spinlock_t sctp_assocs_id_lock;
477 
478 /* Static inline functions. */
479 
480 /* Convert from an IP version number to an Address Family symbol.  */
481 static inline int ipver2af(__u8 ipver)
482 {
483 	switch (ipver) {
484 	case 4:
485 	        return  AF_INET;
486 	case 6:
487 		return AF_INET6;
488 	default:
489 		return 0;
490 	}
491 }
492 
493 /* Convert from an address parameter type to an address family.  */
494 static inline int param_type2af(__be16 type)
495 {
496 	switch (type) {
497 	case SCTP_PARAM_IPV4_ADDRESS:
498 	        return  AF_INET;
499 	case SCTP_PARAM_IPV6_ADDRESS:
500 		return AF_INET6;
501 	default:
502 		return 0;
503 	}
504 }
505 
506 /* Warning: The following hash functions assume a power of two 'size'. */
507 /* This is the hash function for the SCTP port hash table. */
508 static inline int sctp_phashfn(struct net *net, __u16 lport)
509 {
510 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
511 }
512 
513 /* This is the hash function for the endpoint hash table. */
514 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
515 {
516 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
517 }
518 
519 /* This is the hash function for the association hash table. */
520 static inline int sctp_assoc_hashfn(struct net *net, __u16 lport, __u16 rport)
521 {
522 	int h = (lport << 16) + rport + net_hash_mix(net);
523 	h ^= h>>8;
524 	return h & (sctp_assoc_hashsize - 1);
525 }
526 
527 /* This is the hash function for the association hash table.  This is
528  * not used yet, but could be used as a better hash function when
529  * we have a vtag.
530  */
531 static inline int sctp_vtag_hashfn(__u16 lport, __u16 rport, __u32 vtag)
532 {
533 	int h = (lport << 16) + rport;
534 	h ^= vtag;
535 	return h & (sctp_assoc_hashsize - 1);
536 }
537 
538 #define sctp_for_each_hentry(epb, head) \
539 	hlist_for_each_entry(epb, head, node)
540 
541 /* Is a socket of this style? */
542 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
543 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
544 {
545 	return sctp_sk(sk)->type == style;
546 }
547 
548 /* Is the association in this state? */
549 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
550 static inline int __sctp_state(const struct sctp_association *asoc,
551 			       sctp_state_t state)
552 {
553 	return asoc->state == state;
554 }
555 
556 /* Is the socket in this state? */
557 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
558 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
559 {
560 	return sk->sk_state == state;
561 }
562 
563 /* Map v4-mapped v6 address back to v4 address */
564 static inline void sctp_v6_map_v4(union sctp_addr *addr)
565 {
566 	addr->v4.sin_family = AF_INET;
567 	addr->v4.sin_port = addr->v6.sin6_port;
568 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
569 }
570 
571 /* Map v4 address to v4-mapped v6 address */
572 static inline void sctp_v4_map_v6(union sctp_addr *addr)
573 {
574 	addr->v6.sin6_family = AF_INET6;
575 	addr->v6.sin6_flowinfo = 0;
576 	addr->v6.sin6_scope_id = 0;
577 	addr->v6.sin6_port = addr->v4.sin_port;
578 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
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