xref: /openbmc/linux/include/net/sctp/sctp.h (revision 1c2dd16a)
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 int sctp_primitive_RECONF(struct net *net, struct sctp_association *asoc,
145 			  void *arg);
146 
147 /*
148  * sctp/input.c
149  */
150 int sctp_rcv(struct sk_buff *skb);
151 void sctp_v4_err(struct sk_buff *skb, u32 info);
152 void sctp_hash_endpoint(struct sctp_endpoint *);
153 void sctp_unhash_endpoint(struct sctp_endpoint *);
154 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
155 			     struct sctphdr *, struct sctp_association **,
156 			     struct sctp_transport **);
157 void sctp_err_finish(struct sock *, struct sctp_transport *);
158 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
159 			   struct sctp_transport *t, __u32 pmtu);
160 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
161 			struct sk_buff *);
162 void sctp_icmp_proto_unreachable(struct sock *sk,
163 				 struct sctp_association *asoc,
164 				 struct sctp_transport *t);
165 void sctp_backlog_migrate(struct sctp_association *assoc,
166 			  struct sock *oldsk, struct sock *newsk);
167 int sctp_transport_hashtable_init(void);
168 void sctp_transport_hashtable_destroy(void);
169 int sctp_hash_transport(struct sctp_transport *t);
170 void sctp_unhash_transport(struct sctp_transport *t);
171 struct sctp_transport *sctp_addrs_lookup_transport(
172 				struct net *net,
173 				const union sctp_addr *laddr,
174 				const union sctp_addr *paddr);
175 struct sctp_transport *sctp_epaddr_lookup_transport(
176 				const struct sctp_endpoint *ep,
177 				const union sctp_addr *paddr);
178 
179 /*
180  * sctp/proc.c
181  */
182 int sctp_snmp_proc_init(struct net *net);
183 void sctp_snmp_proc_exit(struct net *net);
184 int sctp_eps_proc_init(struct net *net);
185 void sctp_eps_proc_exit(struct net *net);
186 int sctp_assocs_proc_init(struct net *net);
187 void sctp_assocs_proc_exit(struct net *net);
188 int sctp_remaddr_proc_init(struct net *net);
189 void sctp_remaddr_proc_exit(struct net *net);
190 
191 /*
192  * sctp/offload.c
193  */
194 int sctp_offload_init(void);
195 
196 /*
197  * sctp/stream.c
198  */
199 int sctp_send_reset_streams(struct sctp_association *asoc,
200 			    struct sctp_reset_streams *params);
201 int sctp_send_reset_assoc(struct sctp_association *asoc);
202 int sctp_send_add_streams(struct sctp_association *asoc,
203 			  struct sctp_add_streams *params);
204 
205 /*
206  * Module global variables
207  */
208 
209  /*
210   * sctp/protocol.c
211   */
212 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
213 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
214 extern long sysctl_sctp_mem[3];
215 extern int sysctl_sctp_rmem[3];
216 extern int sysctl_sctp_wmem[3];
217 
218 /*
219  *  Section:  Macros, externs, and inlines
220  */
221 
222 /* SCTP SNMP MIB stats handlers */
223 #define SCTP_INC_STATS(net, field)	SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
224 #define __SCTP_INC_STATS(net, field)	__SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
225 #define SCTP_DEC_STATS(net, field)	SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
226 
227 /* sctp mib definitions */
228 enum {
229 	SCTP_MIB_NUM = 0,
230 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
231 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
232 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
233 	SCTP_MIB_ABORTEDS,			/* Aborteds */
234 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
235 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
236 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
237 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
238 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
239 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
240 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
241 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
242 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
243 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
244 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
245 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
246 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
247 	SCTP_MIB_T1_INIT_EXPIREDS,
248 	SCTP_MIB_T1_COOKIE_EXPIREDS,
249 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
250 	SCTP_MIB_T3_RTX_EXPIREDS,
251 	SCTP_MIB_T4_RTO_EXPIREDS,
252 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
253 	SCTP_MIB_DELAY_SACK_EXPIREDS,
254 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
255 	SCTP_MIB_T1_RETRANSMITS,
256 	SCTP_MIB_T3_RETRANSMITS,
257 	SCTP_MIB_PMTUD_RETRANSMITS,
258 	SCTP_MIB_FAST_RETRANSMITS,
259 	SCTP_MIB_IN_PKT_SOFTIRQ,
260 	SCTP_MIB_IN_PKT_BACKLOG,
261 	SCTP_MIB_IN_PKT_DISCARDS,
262 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
263 	__SCTP_MIB_MAX
264 };
265 
266 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
267 struct sctp_mib {
268         unsigned long   mibs[SCTP_MIB_MAX];
269 };
270 
271 /* helper function to track stats about max rto and related transport */
272 static inline void sctp_max_rto(struct sctp_association *asoc,
273 				struct sctp_transport *trans)
274 {
275 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
276 		asoc->stats.max_obs_rto = trans->rto;
277 		memset(&asoc->stats.obs_rto_ipaddr, 0,
278 			sizeof(struct sockaddr_storage));
279 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
280 			trans->af_specific->sockaddr_len);
281 	}
282 }
283 
284 /*
285  * Macros for keeping a global reference of object allocations.
286  */
287 #ifdef CONFIG_SCTP_DBG_OBJCNT
288 
289 extern atomic_t sctp_dbg_objcnt_sock;
290 extern atomic_t sctp_dbg_objcnt_ep;
291 extern atomic_t sctp_dbg_objcnt_assoc;
292 extern atomic_t sctp_dbg_objcnt_transport;
293 extern atomic_t sctp_dbg_objcnt_chunk;
294 extern atomic_t sctp_dbg_objcnt_bind_addr;
295 extern atomic_t sctp_dbg_objcnt_bind_bucket;
296 extern atomic_t sctp_dbg_objcnt_addr;
297 extern atomic_t sctp_dbg_objcnt_datamsg;
298 extern atomic_t sctp_dbg_objcnt_keys;
299 
300 /* Macros to atomically increment/decrement objcnt counters.  */
301 #define SCTP_DBG_OBJCNT_INC(name) \
302 atomic_inc(&sctp_dbg_objcnt_## name)
303 #define SCTP_DBG_OBJCNT_DEC(name) \
304 atomic_dec(&sctp_dbg_objcnt_## name)
305 #define SCTP_DBG_OBJCNT(name) \
306 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
307 
308 /* Macro to help create new entries in in the global array of
309  * objcnt counters.
310  */
311 #define SCTP_DBG_OBJCNT_ENTRY(name) \
312 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
313 
314 void sctp_dbg_objcnt_init(struct net *);
315 void sctp_dbg_objcnt_exit(struct net *);
316 
317 #else
318 
319 #define SCTP_DBG_OBJCNT_INC(name)
320 #define SCTP_DBG_OBJCNT_DEC(name)
321 
322 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
323 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
324 
325 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
326 
327 #if defined CONFIG_SYSCTL
328 void sctp_sysctl_register(void);
329 void sctp_sysctl_unregister(void);
330 int sctp_sysctl_net_register(struct net *net);
331 void sctp_sysctl_net_unregister(struct net *net);
332 #else
333 static inline void sctp_sysctl_register(void) { return; }
334 static inline void sctp_sysctl_unregister(void) { return; }
335 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
336 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
337 #endif
338 
339 /* Size of Supported Address Parameter for 'x' address types. */
340 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
341 
342 #if IS_ENABLED(CONFIG_IPV6)
343 
344 void sctp_v6_pf_init(void);
345 void sctp_v6_pf_exit(void);
346 int sctp_v6_protosw_init(void);
347 void sctp_v6_protosw_exit(void);
348 int sctp_v6_add_protocol(void);
349 void sctp_v6_del_protocol(void);
350 
351 #else /* #ifdef defined(CONFIG_IPV6) */
352 
353 static inline void sctp_v6_pf_init(void) { return; }
354 static inline void sctp_v6_pf_exit(void) { return; }
355 static inline int sctp_v6_protosw_init(void) { return 0; }
356 static inline void sctp_v6_protosw_exit(void) { return; }
357 static inline int sctp_v6_add_protocol(void) { return 0; }
358 static inline void sctp_v6_del_protocol(void) { return; }
359 
360 #endif /* #if defined(CONFIG_IPV6) */
361 
362 
363 /* Map an association to an assoc_id. */
364 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
365 {
366 	return asoc ? asoc->assoc_id : 0;
367 }
368 
369 static inline enum sctp_sstat_state
370 sctp_assoc_to_state(const struct sctp_association *asoc)
371 {
372 	/* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
373 	 * got rid of it in kernel space. Therefore SCTP_CLOSED et al
374 	 * start at =1 in user space, but actually as =0 in kernel space.
375 	 * Now that we can not break user space and SCTP_EMPTY is exposed
376 	 * there, we need to fix it up with an ugly offset not to break
377 	 * applications. :(
378 	 */
379 	return asoc->state + 1;
380 }
381 
382 /* Look up the association by its id.  */
383 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
384 
385 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
386 
387 /* A macro to walk a list of skbs.  */
388 #define sctp_skb_for_each(pos, head, tmp) \
389 	skb_queue_walk_safe(head, pos, tmp)
390 
391 /**
392  *	sctp_list_dequeue - remove from the head of the queue
393  *	@list: list to dequeue from
394  *
395  *	Remove the head of the list. The head item is
396  *	returned or %NULL if the list is empty.
397  */
398 
399 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
400 {
401 	struct list_head *result = NULL;
402 
403 	if (!list_empty(list)) {
404 		result = list->next;
405 		list_del_init(result);
406 	}
407 	return result;
408 }
409 
410 /* SCTP version of skb_set_owner_r.  We need this one because
411  * of the way we have to do receive buffer accounting on bundled
412  * chunks.
413  */
414 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
415 {
416 	struct sctp_ulpevent *event = sctp_skb2event(skb);
417 
418 	skb_orphan(skb);
419 	skb->sk = sk;
420 	skb->destructor = sctp_sock_rfree;
421 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
422 	/*
423 	 * This mimics the behavior of skb_set_owner_r
424 	 */
425 	sk->sk_forward_alloc -= event->rmem_len;
426 }
427 
428 /* Tests if the list has one and only one entry. */
429 static inline int sctp_list_single_entry(struct list_head *head)
430 {
431 	return (head->next != head) && (head->next == head->prev);
432 }
433 
434 /* Break down data chunks at this point.  */
435 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
436 {
437 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
438 	int frag = pmtu;
439 
440 	frag -= sp->pf->af->net_header_len;
441 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
442 
443 	if (asoc->user_frag)
444 		frag = min_t(int, frag, asoc->user_frag);
445 
446 	frag = SCTP_TRUNC4(min_t(int, frag, SCTP_MAX_CHUNK_LEN));
447 
448 	return frag;
449 }
450 
451 static inline void sctp_assoc_pending_pmtu(struct sctp_association *asoc)
452 {
453 	sctp_assoc_sync_pmtu(asoc);
454 	asoc->pmtu_pending = 0;
455 }
456 
457 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
458 {
459 	return !list_empty(&chunk->list);
460 }
461 
462 /* Walk through a list of TLV parameters.  Don't trust the
463  * individual parameter lengths and instead depend on
464  * the chunk length to indicate when to stop.  Make sure
465  * there is room for a param header too.
466  */
467 #define sctp_walk_params(pos, chunk, member)\
468 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
469 
470 #define _sctp_walk_params(pos, chunk, end, member)\
471 for (pos.v = chunk->member;\
472      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
473      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
474      pos.v += SCTP_PAD4(ntohs(pos.p->length)))
475 
476 #define sctp_walk_errors(err, chunk_hdr)\
477 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
478 
479 #define _sctp_walk_errors(err, chunk_hdr, end)\
480 for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
481 	    sizeof(sctp_chunkhdr_t));\
482      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
483      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
484      err = (sctp_errhdr_t *)((void *)err + SCTP_PAD4(ntohs(err->length))))
485 
486 #define sctp_walk_fwdtsn(pos, chunk)\
487 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
488 
489 #define _sctp_walk_fwdtsn(pos, chunk, end)\
490 for (pos = chunk->subh.fwdtsn_hdr->skip;\
491      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
492      pos++)
493 
494 /* External references. */
495 
496 extern struct proto sctp_prot;
497 extern struct proto sctpv6_prot;
498 void sctp_put_port(struct sock *sk);
499 
500 extern struct idr sctp_assocs_id;
501 extern spinlock_t sctp_assocs_id_lock;
502 
503 /* Static inline functions. */
504 
505 /* Convert from an IP version number to an Address Family symbol.  */
506 static inline int ipver2af(__u8 ipver)
507 {
508 	switch (ipver) {
509 	case 4:
510 	        return  AF_INET;
511 	case 6:
512 		return AF_INET6;
513 	default:
514 		return 0;
515 	}
516 }
517 
518 /* Convert from an address parameter type to an address family.  */
519 static inline int param_type2af(__be16 type)
520 {
521 	switch (type) {
522 	case SCTP_PARAM_IPV4_ADDRESS:
523 	        return  AF_INET;
524 	case SCTP_PARAM_IPV6_ADDRESS:
525 		return AF_INET6;
526 	default:
527 		return 0;
528 	}
529 }
530 
531 /* Warning: The following hash functions assume a power of two 'size'. */
532 /* This is the hash function for the SCTP port hash table. */
533 static inline int sctp_phashfn(struct net *net, __u16 lport)
534 {
535 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
536 }
537 
538 /* This is the hash function for the endpoint hash table. */
539 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
540 {
541 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
542 }
543 
544 #define sctp_for_each_hentry(epb, head) \
545 	hlist_for_each_entry(epb, head, node)
546 
547 /* Is a socket of this style? */
548 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
549 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
550 {
551 	return sctp_sk(sk)->type == style;
552 }
553 
554 /* Is the association in this state? */
555 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
556 static inline int __sctp_state(const struct sctp_association *asoc,
557 			       sctp_state_t state)
558 {
559 	return asoc->state == state;
560 }
561 
562 /* Is the socket in this state? */
563 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
564 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
565 {
566 	return sk->sk_state == state;
567 }
568 
569 /* Map v4-mapped v6 address back to v4 address */
570 static inline void sctp_v6_map_v4(union sctp_addr *addr)
571 {
572 	addr->v4.sin_family = AF_INET;
573 	addr->v4.sin_port = addr->v6.sin6_port;
574 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
575 }
576 
577 /* Map v4 address to v4-mapped v6 address */
578 static inline void sctp_v4_map_v6(union sctp_addr *addr)
579 {
580 	__be16 port;
581 
582 	port = addr->v4.sin_port;
583 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
584 	addr->v6.sin6_port = port;
585 	addr->v6.sin6_family = AF_INET6;
586 	addr->v6.sin6_flowinfo = 0;
587 	addr->v6.sin6_scope_id = 0;
588 	addr->v6.sin6_addr.s6_addr32[0] = 0;
589 	addr->v6.sin6_addr.s6_addr32[1] = 0;
590 	addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
591 }
592 
593 /* The cookie is always 0 since this is how it's used in the
594  * pmtu code.
595  */
596 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
597 {
598 	if (t->dst && !dst_check(t->dst, t->dst_cookie))
599 		sctp_transport_dst_release(t);
600 
601 	return t->dst;
602 }
603 
604 static inline bool sctp_transport_pmtu_check(struct sctp_transport *t)
605 {
606 	__u32 pmtu = max_t(size_t, SCTP_TRUNC4(dst_mtu(t->dst)),
607 			   SCTP_DEFAULT_MINSEGMENT);
608 
609 	if (t->pathmtu == pmtu)
610 		return true;
611 
612 	t->pathmtu = pmtu;
613 
614 	return false;
615 }
616 
617 #endif /* __net_sctp_h__ */
618