xref: /linux/include/net/sctp/sctp.h (revision f87be8948185a4f1085aea38bccd0d2ce07f711c)
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 *net, struct sctp_bind_addr *addr,
98 			      enum sctp_scope, 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 __poll_t sctp_poll_mask(struct socket *sock, __poll_t events);
111 void sctp_sock_rfree(struct sk_buff *skb);
112 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
113 		    struct sctp_association *asoc);
114 extern struct percpu_counter sctp_sockets_allocated;
115 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
116 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
117 
118 void sctp_transport_walk_start(struct rhashtable_iter *iter);
119 void sctp_transport_walk_stop(struct rhashtable_iter *iter);
120 struct sctp_transport *sctp_transport_get_next(struct net *net,
121 			struct rhashtable_iter *iter);
122 struct sctp_transport *sctp_transport_get_idx(struct net *net,
123 			struct rhashtable_iter *iter, int pos);
124 int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
125 				  struct net *net,
126 				  const union sctp_addr *laddr,
127 				  const union sctp_addr *paddr, void *p);
128 int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
129 			    int (*cb_done)(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 __net_init sctp_proc_init(struct net *net);
183 
184 /*
185  * sctp/offload.c
186  */
187 int sctp_offload_init(void);
188 
189 /*
190  * sctp/stream_sched.c
191  */
192 void sctp_sched_ops_init(void);
193 
194 /*
195  * sctp/stream.c
196  */
197 int sctp_send_reset_streams(struct sctp_association *asoc,
198 			    struct sctp_reset_streams *params);
199 int sctp_send_reset_assoc(struct sctp_association *asoc);
200 int sctp_send_add_streams(struct sctp_association *asoc,
201 			  struct sctp_add_streams *params);
202 
203 /*
204  * Module global variables
205  */
206 
207  /*
208   * sctp/protocol.c
209   */
210 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
211 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
212 extern long sysctl_sctp_mem[3];
213 extern int sysctl_sctp_rmem[3];
214 extern int sysctl_sctp_wmem[3];
215 
216 /*
217  *  Section:  Macros, externs, and inlines
218  */
219 
220 /* SCTP SNMP MIB stats handlers */
221 #define SCTP_INC_STATS(net, field)	SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
222 #define __SCTP_INC_STATS(net, field)	__SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
223 #define SCTP_DEC_STATS(net, field)	SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
224 
225 /* sctp mib definitions */
226 enum {
227 	SCTP_MIB_NUM = 0,
228 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
229 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
230 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
231 	SCTP_MIB_ABORTEDS,			/* Aborteds */
232 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
233 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
234 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
235 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
236 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
237 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
238 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
239 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
240 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
241 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
242 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
243 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
244 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
245 	SCTP_MIB_T1_INIT_EXPIREDS,
246 	SCTP_MIB_T1_COOKIE_EXPIREDS,
247 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
248 	SCTP_MIB_T3_RTX_EXPIREDS,
249 	SCTP_MIB_T4_RTO_EXPIREDS,
250 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
251 	SCTP_MIB_DELAY_SACK_EXPIREDS,
252 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
253 	SCTP_MIB_T1_RETRANSMITS,
254 	SCTP_MIB_T3_RETRANSMITS,
255 	SCTP_MIB_PMTUD_RETRANSMITS,
256 	SCTP_MIB_FAST_RETRANSMITS,
257 	SCTP_MIB_IN_PKT_SOFTIRQ,
258 	SCTP_MIB_IN_PKT_BACKLOG,
259 	SCTP_MIB_IN_PKT_DISCARDS,
260 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
261 	__SCTP_MIB_MAX
262 };
263 
264 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
265 struct sctp_mib {
266         unsigned long   mibs[SCTP_MIB_MAX];
267 };
268 
269 /* helper function to track stats about max rto and related transport */
270 static inline void sctp_max_rto(struct sctp_association *asoc,
271 				struct sctp_transport *trans)
272 {
273 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
274 		asoc->stats.max_obs_rto = trans->rto;
275 		memset(&asoc->stats.obs_rto_ipaddr, 0,
276 			sizeof(struct sockaddr_storage));
277 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
278 			trans->af_specific->sockaddr_len);
279 	}
280 }
281 
282 /*
283  * Macros for keeping a global reference of object allocations.
284  */
285 #ifdef CONFIG_SCTP_DBG_OBJCNT
286 
287 extern atomic_t sctp_dbg_objcnt_sock;
288 extern atomic_t sctp_dbg_objcnt_ep;
289 extern atomic_t sctp_dbg_objcnt_assoc;
290 extern atomic_t sctp_dbg_objcnt_transport;
291 extern atomic_t sctp_dbg_objcnt_chunk;
292 extern atomic_t sctp_dbg_objcnt_bind_addr;
293 extern atomic_t sctp_dbg_objcnt_bind_bucket;
294 extern atomic_t sctp_dbg_objcnt_addr;
295 extern atomic_t sctp_dbg_objcnt_datamsg;
296 extern atomic_t sctp_dbg_objcnt_keys;
297 
298 /* Macros to atomically increment/decrement objcnt counters.  */
299 #define SCTP_DBG_OBJCNT_INC(name) \
300 atomic_inc(&sctp_dbg_objcnt_## name)
301 #define SCTP_DBG_OBJCNT_DEC(name) \
302 atomic_dec(&sctp_dbg_objcnt_## name)
303 #define SCTP_DBG_OBJCNT(name) \
304 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
305 
306 /* Macro to help create new entries in in the global array of
307  * objcnt counters.
308  */
309 #define SCTP_DBG_OBJCNT_ENTRY(name) \
310 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
311 
312 void sctp_dbg_objcnt_init(struct net *);
313 
314 #else
315 
316 #define SCTP_DBG_OBJCNT_INC(name)
317 #define SCTP_DBG_OBJCNT_DEC(name)
318 
319 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
320 
321 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
322 
323 #if defined CONFIG_SYSCTL
324 void sctp_sysctl_register(void);
325 void sctp_sysctl_unregister(void);
326 int sctp_sysctl_net_register(struct net *net);
327 void sctp_sysctl_net_unregister(struct net *net);
328 #else
329 static inline void sctp_sysctl_register(void) { return; }
330 static inline void sctp_sysctl_unregister(void) { return; }
331 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
332 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
333 #endif
334 
335 /* Size of Supported Address Parameter for 'x' address types. */
336 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
337 
338 #if IS_ENABLED(CONFIG_IPV6)
339 
340 void sctp_v6_pf_init(void);
341 void sctp_v6_pf_exit(void);
342 int sctp_v6_protosw_init(void);
343 void sctp_v6_protosw_exit(void);
344 int sctp_v6_add_protocol(void);
345 void sctp_v6_del_protocol(void);
346 
347 #else /* #ifdef defined(CONFIG_IPV6) */
348 
349 static inline void sctp_v6_pf_init(void) { return; }
350 static inline void sctp_v6_pf_exit(void) { return; }
351 static inline int sctp_v6_protosw_init(void) { return 0; }
352 static inline void sctp_v6_protosw_exit(void) { return; }
353 static inline int sctp_v6_add_protocol(void) { return 0; }
354 static inline void sctp_v6_del_protocol(void) { return; }
355 
356 #endif /* #if defined(CONFIG_IPV6) */
357 
358 
359 /* Map an association to an assoc_id. */
360 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
361 {
362 	return asoc ? asoc->assoc_id : 0;
363 }
364 
365 static inline enum sctp_sstat_state
366 sctp_assoc_to_state(const struct sctp_association *asoc)
367 {
368 	/* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
369 	 * got rid of it in kernel space. Therefore SCTP_CLOSED et al
370 	 * start at =1 in user space, but actually as =0 in kernel space.
371 	 * Now that we can not break user space and SCTP_EMPTY is exposed
372 	 * there, we need to fix it up with an ugly offset not to break
373 	 * applications. :(
374 	 */
375 	return asoc->state + 1;
376 }
377 
378 /* Look up the association by its id.  */
379 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
380 
381 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
382 
383 /* A macro to walk a list of skbs.  */
384 #define sctp_skb_for_each(pos, head, tmp) \
385 	skb_queue_walk_safe(head, pos, tmp)
386 
387 /**
388  *	sctp_list_dequeue - remove from the head of the queue
389  *	@list: list to dequeue from
390  *
391  *	Remove the head of the list. The head item is
392  *	returned or %NULL if the list is empty.
393  */
394 
395 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
396 {
397 	struct list_head *result = NULL;
398 
399 	if (!list_empty(list)) {
400 		result = list->next;
401 		list_del_init(result);
402 	}
403 	return result;
404 }
405 
406 /* SCTP version of skb_set_owner_r.  We need this one because
407  * of the way we have to do receive buffer accounting on bundled
408  * chunks.
409  */
410 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
411 {
412 	struct sctp_ulpevent *event = sctp_skb2event(skb);
413 
414 	skb_orphan(skb);
415 	skb->sk = sk;
416 	skb->destructor = sctp_sock_rfree;
417 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
418 	/*
419 	 * This mimics the behavior of skb_set_owner_r
420 	 */
421 	sk->sk_forward_alloc -= event->rmem_len;
422 }
423 
424 /* Tests if the list has one and only one entry. */
425 static inline int sctp_list_single_entry(struct list_head *head)
426 {
427 	return (head->next != head) && (head->next == head->prev);
428 }
429 
430 /* Break down data chunks at this point.  */
431 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
432 {
433 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
434 	struct sctp_af *af = sp->pf->af;
435 	int frag = pmtu;
436 
437 	frag -= af->ip_options_len(asoc->base.sk);
438 	frag -= af->net_header_len;
439 	frag -= sizeof(struct sctphdr) + sctp_datachk_len(&asoc->stream);
440 
441 	if (asoc->user_frag)
442 		frag = min_t(int, frag, asoc->user_frag);
443 
444 	frag = SCTP_TRUNC4(min_t(int, frag, SCTP_MAX_CHUNK_LEN -
445 					    sctp_datachk_len(&asoc->stream)));
446 
447 	return frag;
448 }
449 
450 static inline void sctp_assoc_pending_pmtu(struct sctp_association *asoc)
451 {
452 	sctp_assoc_sync_pmtu(asoc);
453 	asoc->pmtu_pending = 0;
454 }
455 
456 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
457 {
458 	return !list_empty(&chunk->list);
459 }
460 
461 /* Walk through a list of TLV parameters.  Don't trust the
462  * individual parameter lengths and instead depend on
463  * the chunk length to indicate when to stop.  Make sure
464  * there is room for a param header too.
465  */
466 #define sctp_walk_params(pos, chunk, member)\
467 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
468 
469 #define _sctp_walk_params(pos, chunk, end, member)\
470 for (pos.v = chunk->member;\
471      (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <=\
472       (void *)chunk + end) &&\
473      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
474      ntohs(pos.p->length) >= sizeof(struct sctp_paramhdr);\
475      pos.v += SCTP_PAD4(ntohs(pos.p->length)))
476 
477 #define sctp_walk_errors(err, chunk_hdr)\
478 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
479 
480 #define _sctp_walk_errors(err, chunk_hdr, end)\
481 for (err = (struct sctp_errhdr *)((void *)chunk_hdr + \
482 	    sizeof(struct sctp_chunkhdr));\
483      ((void *)err + offsetof(struct sctp_errhdr, length) + sizeof(err->length) <=\
484       (void *)chunk_hdr + end) &&\
485      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
486      ntohs(err->length) >= sizeof(struct sctp_errhdr); \
487      err = (struct sctp_errhdr *)((void *)err + SCTP_PAD4(ntohs(err->length))))
488 
489 #define sctp_walk_fwdtsn(pos, chunk)\
490 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
491 
492 #define _sctp_walk_fwdtsn(pos, chunk, end)\
493 for (pos = chunk->subh.fwdtsn_hdr->skip;\
494      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
495      pos++)
496 
497 /* External references. */
498 
499 extern struct proto sctp_prot;
500 extern struct proto sctpv6_prot;
501 void sctp_put_port(struct sock *sk);
502 
503 extern struct idr sctp_assocs_id;
504 extern spinlock_t sctp_assocs_id_lock;
505 
506 /* Static inline functions. */
507 
508 /* Convert from an IP version number to an Address Family symbol.  */
509 static inline int ipver2af(__u8 ipver)
510 {
511 	switch (ipver) {
512 	case 4:
513 	        return  AF_INET;
514 	case 6:
515 		return AF_INET6;
516 	default:
517 		return 0;
518 	}
519 }
520 
521 /* Convert from an address parameter type to an address family.  */
522 static inline int param_type2af(__be16 type)
523 {
524 	switch (type) {
525 	case SCTP_PARAM_IPV4_ADDRESS:
526 	        return  AF_INET;
527 	case SCTP_PARAM_IPV6_ADDRESS:
528 		return AF_INET6;
529 	default:
530 		return 0;
531 	}
532 }
533 
534 /* Warning: The following hash functions assume a power of two 'size'. */
535 /* This is the hash function for the SCTP port hash table. */
536 static inline int sctp_phashfn(struct net *net, __u16 lport)
537 {
538 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
539 }
540 
541 /* This is the hash function for the endpoint hash table. */
542 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
543 {
544 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
545 }
546 
547 #define sctp_for_each_hentry(epb, head) \
548 	hlist_for_each_entry(epb, head, node)
549 
550 /* Is a socket of this style? */
551 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
552 static inline int __sctp_style(const struct sock *sk,
553 			       enum sctp_socket_type style)
554 {
555 	return sctp_sk(sk)->type == style;
556 }
557 
558 /* Is the association in this state? */
559 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
560 static inline int __sctp_state(const struct sctp_association *asoc,
561 			       enum sctp_state state)
562 {
563 	return asoc->state == state;
564 }
565 
566 /* Is the socket in this state? */
567 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
568 static inline int __sctp_sstate(const struct sock *sk,
569 				enum sctp_sock_state state)
570 {
571 	return sk->sk_state == state;
572 }
573 
574 /* Map v4-mapped v6 address back to v4 address */
575 static inline void sctp_v6_map_v4(union sctp_addr *addr)
576 {
577 	addr->v4.sin_family = AF_INET;
578 	addr->v4.sin_port = addr->v6.sin6_port;
579 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
580 }
581 
582 /* Map v4 address to v4-mapped v6 address */
583 static inline void sctp_v4_map_v6(union sctp_addr *addr)
584 {
585 	__be16 port;
586 
587 	port = addr->v4.sin_port;
588 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
589 	addr->v6.sin6_port = port;
590 	addr->v6.sin6_family = AF_INET6;
591 	addr->v6.sin6_flowinfo = 0;
592 	addr->v6.sin6_scope_id = 0;
593 	addr->v6.sin6_addr.s6_addr32[0] = 0;
594 	addr->v6.sin6_addr.s6_addr32[1] = 0;
595 	addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
596 }
597 
598 /* The cookie is always 0 since this is how it's used in the
599  * pmtu code.
600  */
601 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
602 {
603 	if (t->dst && !dst_check(t->dst, t->dst_cookie))
604 		sctp_transport_dst_release(t);
605 
606 	return t->dst;
607 }
608 
609 static inline bool sctp_transport_pmtu_check(struct sctp_transport *t)
610 {
611 	__u32 pmtu = max_t(size_t, SCTP_TRUNC4(dst_mtu(t->dst)),
612 			   SCTP_DEFAULT_MINSEGMENT);
613 
614 	if (t->pathmtu == pmtu)
615 		return true;
616 
617 	t->pathmtu = pmtu;
618 
619 	return false;
620 }
621 
622 #endif /* __net_sctp_h__ */
623