xref: /linux/include/net/sctp/sctp.h (revision d91517839e5d95adc0cf4b28caa7af62a71de526)
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, int len);
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 
113 /*
114  * sctp/primitive.c
115  */
116 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
117 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
118 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
119 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
120 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
121 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
122 
123 /*
124  * sctp/input.c
125  */
126 int sctp_rcv(struct sk_buff *skb);
127 void sctp_v4_err(struct sk_buff *skb, u32 info);
128 void sctp_hash_established(struct sctp_association *);
129 void sctp_unhash_established(struct sctp_association *);
130 void sctp_hash_endpoint(struct sctp_endpoint *);
131 void sctp_unhash_endpoint(struct sctp_endpoint *);
132 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
133 			     struct sctphdr *, struct sctp_association **,
134 			     struct sctp_transport **);
135 void sctp_err_finish(struct sock *, struct sctp_association *);
136 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
137 			   struct sctp_transport *t, __u32 pmtu);
138 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
139 			struct sk_buff *);
140 void sctp_icmp_proto_unreachable(struct sock *sk,
141 				 struct sctp_association *asoc,
142 				 struct sctp_transport *t);
143 void sctp_backlog_migrate(struct sctp_association *assoc,
144 			  struct sock *oldsk, struct sock *newsk);
145 
146 /*
147  * sctp/proc.c
148  */
149 int sctp_snmp_proc_init(struct net *net);
150 void sctp_snmp_proc_exit(struct net *net);
151 int sctp_eps_proc_init(struct net *net);
152 void sctp_eps_proc_exit(struct net *net);
153 int sctp_assocs_proc_init(struct net *net);
154 void sctp_assocs_proc_exit(struct net *net);
155 int sctp_remaddr_proc_init(struct net *net);
156 void sctp_remaddr_proc_exit(struct net *net);
157 
158 
159 /*
160  * Module global variables
161  */
162 
163  /*
164   * sctp/protocol.c
165   */
166 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
167 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
168 
169 /*
170  *  Section:  Macros, externs, and inlines
171  */
172 
173 /* SCTP SNMP MIB stats handlers */
174 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
175 #define SCTP_INC_STATS_BH(net, field)   SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
176 #define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
177 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
178 
179 /* sctp mib definitions */
180 enum {
181 	SCTP_MIB_NUM = 0,
182 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
183 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
184 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
185 	SCTP_MIB_ABORTEDS,			/* Aborteds */
186 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
187 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
188 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
189 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
190 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
191 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
192 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
193 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
194 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
195 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
196 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
197 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
198 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
199 	SCTP_MIB_T1_INIT_EXPIREDS,
200 	SCTP_MIB_T1_COOKIE_EXPIREDS,
201 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
202 	SCTP_MIB_T3_RTX_EXPIREDS,
203 	SCTP_MIB_T4_RTO_EXPIREDS,
204 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
205 	SCTP_MIB_DELAY_SACK_EXPIREDS,
206 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
207 	SCTP_MIB_T1_RETRANSMITS,
208 	SCTP_MIB_T3_RETRANSMITS,
209 	SCTP_MIB_PMTUD_RETRANSMITS,
210 	SCTP_MIB_FAST_RETRANSMITS,
211 	SCTP_MIB_IN_PKT_SOFTIRQ,
212 	SCTP_MIB_IN_PKT_BACKLOG,
213 	SCTP_MIB_IN_PKT_DISCARDS,
214 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
215 	__SCTP_MIB_MAX
216 };
217 
218 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
219 struct sctp_mib {
220         unsigned long   mibs[SCTP_MIB_MAX];
221 };
222 
223 /* helper function to track stats about max rto and related transport */
224 static inline void sctp_max_rto(struct sctp_association *asoc,
225 				struct sctp_transport *trans)
226 {
227 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
228 		asoc->stats.max_obs_rto = trans->rto;
229 		memset(&asoc->stats.obs_rto_ipaddr, 0,
230 			sizeof(struct sockaddr_storage));
231 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
232 			trans->af_specific->sockaddr_len);
233 	}
234 }
235 
236 /*
237  * Macros for keeping a global reference of object allocations.
238  */
239 #ifdef CONFIG_SCTP_DBG_OBJCNT
240 
241 extern atomic_t sctp_dbg_objcnt_sock;
242 extern atomic_t sctp_dbg_objcnt_ep;
243 extern atomic_t sctp_dbg_objcnt_assoc;
244 extern atomic_t sctp_dbg_objcnt_transport;
245 extern atomic_t sctp_dbg_objcnt_chunk;
246 extern atomic_t sctp_dbg_objcnt_bind_addr;
247 extern atomic_t sctp_dbg_objcnt_bind_bucket;
248 extern atomic_t sctp_dbg_objcnt_addr;
249 extern atomic_t sctp_dbg_objcnt_ssnmap;
250 extern atomic_t sctp_dbg_objcnt_datamsg;
251 extern atomic_t sctp_dbg_objcnt_keys;
252 
253 /* Macros to atomically increment/decrement objcnt counters.  */
254 #define SCTP_DBG_OBJCNT_INC(name) \
255 atomic_inc(&sctp_dbg_objcnt_## name)
256 #define SCTP_DBG_OBJCNT_DEC(name) \
257 atomic_dec(&sctp_dbg_objcnt_## name)
258 #define SCTP_DBG_OBJCNT(name) \
259 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
260 
261 /* Macro to help create new entries in in the global array of
262  * objcnt counters.
263  */
264 #define SCTP_DBG_OBJCNT_ENTRY(name) \
265 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
266 
267 void sctp_dbg_objcnt_init(struct net *);
268 void sctp_dbg_objcnt_exit(struct net *);
269 
270 #else
271 
272 #define SCTP_DBG_OBJCNT_INC(name)
273 #define SCTP_DBG_OBJCNT_DEC(name)
274 
275 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
276 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
277 
278 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
279 
280 #if defined CONFIG_SYSCTL
281 void sctp_sysctl_register(void);
282 void sctp_sysctl_unregister(void);
283 int sctp_sysctl_net_register(struct net *net);
284 void sctp_sysctl_net_unregister(struct net *net);
285 #else
286 static inline void sctp_sysctl_register(void) { return; }
287 static inline void sctp_sysctl_unregister(void) { return; }
288 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
289 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
290 #endif
291 
292 /* Size of Supported Address Parameter for 'x' address types. */
293 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
294 
295 #if IS_ENABLED(CONFIG_IPV6)
296 
297 void sctp_v6_pf_init(void);
298 void sctp_v6_pf_exit(void);
299 int sctp_v6_protosw_init(void);
300 void sctp_v6_protosw_exit(void);
301 int sctp_v6_add_protocol(void);
302 void sctp_v6_del_protocol(void);
303 
304 #else /* #ifdef defined(CONFIG_IPV6) */
305 
306 static inline void sctp_v6_pf_init(void) { return; }
307 static inline void sctp_v6_pf_exit(void) { return; }
308 static inline int sctp_v6_protosw_init(void) { return 0; }
309 static inline void sctp_v6_protosw_exit(void) { return; }
310 static inline int sctp_v6_add_protocol(void) { return 0; }
311 static inline void sctp_v6_del_protocol(void) { return; }
312 
313 #endif /* #if defined(CONFIG_IPV6) */
314 
315 
316 /* Map an association to an assoc_id. */
317 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
318 {
319 	return asoc ? asoc->assoc_id : 0;
320 }
321 
322 /* Look up the association by its id.  */
323 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
324 
325 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
326 
327 /* A macro to walk a list of skbs.  */
328 #define sctp_skb_for_each(pos, head, tmp) \
329 	skb_queue_walk_safe(head, pos, tmp)
330 
331 /* A helper to append an entire skb list (list) to another (head). */
332 static inline void sctp_skb_list_tail(struct sk_buff_head *list,
333 				      struct sk_buff_head *head)
334 {
335 	unsigned long flags;
336 
337 	spin_lock_irqsave(&head->lock, flags);
338 	spin_lock(&list->lock);
339 
340 	skb_queue_splice_tail_init(list, head);
341 
342 	spin_unlock(&list->lock);
343 	spin_unlock_irqrestore(&head->lock, flags);
344 }
345 
346 /**
347  *	sctp_list_dequeue - remove from the head of the queue
348  *	@list: list to dequeue from
349  *
350  *	Remove the head of the list. The head item is
351  *	returned or %NULL if the list is empty.
352  */
353 
354 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
355 {
356 	struct list_head *result = NULL;
357 
358 	if (list->next != list) {
359 		result = list->next;
360 		list->next = result->next;
361 		list->next->prev = list;
362 		INIT_LIST_HEAD(result);
363 	}
364 	return result;
365 }
366 
367 /* SCTP version of skb_set_owner_r.  We need this one because
368  * of the way we have to do receive buffer accounting on bundled
369  * chunks.
370  */
371 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
372 {
373 	struct sctp_ulpevent *event = sctp_skb2event(skb);
374 
375 	skb_orphan(skb);
376 	skb->sk = sk;
377 	skb->destructor = sctp_sock_rfree;
378 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
379 	/*
380 	 * This mimics the behavior of skb_set_owner_r
381 	 */
382 	sk->sk_forward_alloc -= event->rmem_len;
383 }
384 
385 /* Tests if the list has one and only one entry. */
386 static inline int sctp_list_single_entry(struct list_head *head)
387 {
388 	return (head->next != head) && (head->next == head->prev);
389 }
390 
391 /* Generate a random jitter in the range of -50% ~ +50% of input RTO. */
392 static inline __s32 sctp_jitter(__u32 rto)
393 {
394 	static __u32 sctp_rand;
395 	__s32 ret;
396 
397 	/* Avoid divide by zero. */
398 	if (!rto)
399 		rto = 1;
400 
401 	sctp_rand += jiffies;
402 	sctp_rand ^= (sctp_rand << 12);
403 	sctp_rand ^= (sctp_rand >> 20);
404 
405 	/* Choose random number from 0 to rto, then move to -50% ~ +50%
406 	 * of rto.
407 	 */
408 	ret = sctp_rand % rto - (rto >> 1);
409 	return ret;
410 }
411 
412 /* Break down data chunks at this point.  */
413 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
414 {
415 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
416 	int frag = pmtu;
417 
418 	frag -= sp->pf->af->net_header_len;
419 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
420 
421 	if (asoc->user_frag)
422 		frag = min_t(int, frag, asoc->user_frag);
423 
424 	frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);
425 
426 	return frag;
427 }
428 
429 static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
430 {
431 
432 	sctp_assoc_sync_pmtu(sk, asoc);
433 	asoc->pmtu_pending = 0;
434 }
435 
436 /* Walk through a list of TLV parameters.  Don't trust the
437  * individual parameter lengths and instead depend on
438  * the chunk length to indicate when to stop.  Make sure
439  * there is room for a param header too.
440  */
441 #define sctp_walk_params(pos, chunk, member)\
442 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
443 
444 #define _sctp_walk_params(pos, chunk, end, member)\
445 for (pos.v = chunk->member;\
446      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
447      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
448      pos.v += WORD_ROUND(ntohs(pos.p->length)))
449 
450 #define sctp_walk_errors(err, chunk_hdr)\
451 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
452 
453 #define _sctp_walk_errors(err, chunk_hdr, end)\
454 for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
455 	    sizeof(sctp_chunkhdr_t));\
456      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
457      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
458      err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
459 
460 #define sctp_walk_fwdtsn(pos, chunk)\
461 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
462 
463 #define _sctp_walk_fwdtsn(pos, chunk, end)\
464 for (pos = chunk->subh.fwdtsn_hdr->skip;\
465      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
466      pos++)
467 
468 /* Round an int up to the next multiple of 4.  */
469 #define WORD_ROUND(s) (((s)+3)&~3)
470 
471 /* External references. */
472 
473 extern struct proto sctp_prot;
474 extern struct proto sctpv6_prot;
475 void sctp_put_port(struct sock *sk);
476 
477 extern struct idr sctp_assocs_id;
478 extern spinlock_t sctp_assocs_id_lock;
479 
480 /* Static inline functions. */
481 
482 /* Convert from an IP version number to an Address Family symbol.  */
483 static inline int ipver2af(__u8 ipver)
484 {
485 	switch (ipver) {
486 	case 4:
487 	        return  AF_INET;
488 	case 6:
489 		return AF_INET6;
490 	default:
491 		return 0;
492 	}
493 }
494 
495 /* Convert from an address parameter type to an address family.  */
496 static inline int param_type2af(__be16 type)
497 {
498 	switch (type) {
499 	case SCTP_PARAM_IPV4_ADDRESS:
500 	        return  AF_INET;
501 	case SCTP_PARAM_IPV6_ADDRESS:
502 		return AF_INET6;
503 	default:
504 		return 0;
505 	}
506 }
507 
508 /* Warning: The following hash functions assume a power of two 'size'. */
509 /* This is the hash function for the SCTP port hash table. */
510 static inline int sctp_phashfn(struct net *net, __u16 lport)
511 {
512 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
513 }
514 
515 /* This is the hash function for the endpoint hash table. */
516 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
517 {
518 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
519 }
520 
521 /* This is the hash function for the association hash table. */
522 static inline int sctp_assoc_hashfn(struct net *net, __u16 lport, __u16 rport)
523 {
524 	int h = (lport << 16) + rport + net_hash_mix(net);
525 	h ^= h>>8;
526 	return h & (sctp_assoc_hashsize - 1);
527 }
528 
529 /* This is the hash function for the association hash table.  This is
530  * not used yet, but could be used as a better hash function when
531  * we have a vtag.
532  */
533 static inline int sctp_vtag_hashfn(__u16 lport, __u16 rport, __u32 vtag)
534 {
535 	int h = (lport << 16) + rport;
536 	h ^= vtag;
537 	return h & (sctp_assoc_hashsize - 1);
538 }
539 
540 #define sctp_for_each_hentry(epb, head) \
541 	hlist_for_each_entry(epb, head, node)
542 
543 /* Is a socket of this style? */
544 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
545 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
546 {
547 	return sctp_sk(sk)->type == style;
548 }
549 
550 /* Is the association in this state? */
551 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
552 static inline int __sctp_state(const struct sctp_association *asoc,
553 			       sctp_state_t state)
554 {
555 	return asoc->state == state;
556 }
557 
558 /* Is the socket in this state? */
559 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
560 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
561 {
562 	return sk->sk_state == state;
563 }
564 
565 /* Map v4-mapped v6 address back to v4 address */
566 static inline void sctp_v6_map_v4(union sctp_addr *addr)
567 {
568 	addr->v4.sin_family = AF_INET;
569 	addr->v4.sin_port = addr->v6.sin6_port;
570 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
571 }
572 
573 /* Map v4 address to v4-mapped v6 address */
574 static inline void sctp_v4_map_v6(union sctp_addr *addr)
575 {
576 	addr->v6.sin6_family = AF_INET6;
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