xref: /openbmc/linux/include/net/sctp/sctp.h (revision 77d84ff8)
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, write to
25  * the Free Software Foundation, 59 Temple Place - Suite 330,
26  * Boston, MA 02111-1307, USA.
27  *
28  * Please send any bug reports or fixes you make to the
29  * email address(es):
30  *    lksctp developers <linux-sctp@vger.kernel.org>
31  *
32  * Written or modified by:
33  *    La Monte H.P. Yarroll <piggy@acm.org>
34  *    Xingang Guo           <xingang.guo@intel.com>
35  *    Jon Grimm             <jgrimm@us.ibm.com>
36  *    Daisy Chang           <daisyc@us.ibm.com>
37  *    Sridhar Samudrala     <sri@us.ibm.com>
38  *    Ardelle Fan           <ardelle.fan@intel.com>
39  *    Ryan Layer            <rmlayer@us.ibm.com>
40  *    Kevin Gao             <kevin.gao@intel.com>
41  */
42 
43 #ifndef __net_sctp_h__
44 #define __net_sctp_h__
45 
46 /* Header Strategy.
47  *    Start getting some control over the header file depencies:
48  *       includes
49  *       constants
50  *       structs
51  *       prototypes
52  *       macros, externs, and inlines
53  *
54  *   Move test_frame specific items out of the kernel headers
55  *   and into the test frame headers.   This is not perfect in any sense
56  *   and will continue to evolve.
57  */
58 
59 #include <linux/types.h>
60 #include <linux/slab.h>
61 #include <linux/in.h>
62 #include <linux/tty.h>
63 #include <linux/proc_fs.h>
64 #include <linux/spinlock.h>
65 #include <linux/jiffies.h>
66 #include <linux/idr.h>
67 
68 #if IS_ENABLED(CONFIG_IPV6)
69 #include <net/ipv6.h>
70 #include <net/ip6_route.h>
71 #endif
72 
73 #include <asm/uaccess.h>
74 #include <asm/page.h>
75 #include <net/sock.h>
76 #include <net/snmp.h>
77 #include <net/sctp/structs.h>
78 #include <net/sctp/constants.h>
79 
80 #ifdef CONFIG_IP_SCTP_MODULE
81 #define SCTP_PROTOSW_FLAG 0
82 #else /* static! */
83 #define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
84 #endif
85 
86 /*
87  * Function declarations.
88  */
89 
90 /*
91  * sctp/protocol.c
92  */
93 int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
94 			      sctp_scope_t, gfp_t gfp, int flags);
95 struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
96 int sctp_register_pf(struct sctp_pf *, sa_family_t);
97 void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
98 
99 /*
100  * sctp/socket.c
101  */
102 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
103 int sctp_inet_listen(struct socket *sock, int backlog);
104 void sctp_write_space(struct sock *sk);
105 void sctp_data_ready(struct sock *sk, int len);
106 unsigned int sctp_poll(struct file *file, struct socket *sock,
107 		poll_table *wait);
108 void sctp_sock_rfree(struct sk_buff *skb);
109 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
110 		    struct sctp_association *asoc);
111 extern struct percpu_counter sctp_sockets_allocated;
112 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
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 /* spin lock wrappers. */
175 #define sctp_spin_lock_irqsave(lock, flags) spin_lock_irqsave(lock, flags)
176 #define sctp_spin_unlock_irqrestore(lock, flags)  \
177        spin_unlock_irqrestore(lock, flags)
178 #define sctp_local_bh_disable() local_bh_disable()
179 #define sctp_local_bh_enable()  local_bh_enable()
180 #define sctp_spin_lock(lock)    spin_lock(lock)
181 #define sctp_spin_unlock(lock)  spin_unlock(lock)
182 #define sctp_write_lock(lock)   write_lock(lock)
183 #define sctp_write_unlock(lock) write_unlock(lock)
184 #define sctp_read_lock(lock)    read_lock(lock)
185 #define sctp_read_unlock(lock)  read_unlock(lock)
186 
187 /* sock lock wrappers. */
188 #define sctp_lock_sock(sk)       lock_sock(sk)
189 #define sctp_release_sock(sk)    release_sock(sk)
190 #define sctp_bh_lock_sock(sk)    bh_lock_sock(sk)
191 #define sctp_bh_unlock_sock(sk)  bh_unlock_sock(sk)
192 
193 /* SCTP SNMP MIB stats handlers */
194 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
195 #define SCTP_INC_STATS_BH(net, field)   SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
196 #define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
197 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
198 
199 /* sctp mib definitions */
200 enum {
201 	SCTP_MIB_NUM = 0,
202 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
203 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
204 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
205 	SCTP_MIB_ABORTEDS,			/* Aborteds */
206 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
207 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
208 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
209 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
210 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
211 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
212 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
213 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
214 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
215 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
216 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
217 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
218 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
219 	SCTP_MIB_T1_INIT_EXPIREDS,
220 	SCTP_MIB_T1_COOKIE_EXPIREDS,
221 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
222 	SCTP_MIB_T3_RTX_EXPIREDS,
223 	SCTP_MIB_T4_RTO_EXPIREDS,
224 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
225 	SCTP_MIB_DELAY_SACK_EXPIREDS,
226 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
227 	SCTP_MIB_T1_RETRANSMITS,
228 	SCTP_MIB_T3_RETRANSMITS,
229 	SCTP_MIB_PMTUD_RETRANSMITS,
230 	SCTP_MIB_FAST_RETRANSMITS,
231 	SCTP_MIB_IN_PKT_SOFTIRQ,
232 	SCTP_MIB_IN_PKT_BACKLOG,
233 	SCTP_MIB_IN_PKT_DISCARDS,
234 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
235 	__SCTP_MIB_MAX
236 };
237 
238 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
239 struct sctp_mib {
240         unsigned long   mibs[SCTP_MIB_MAX];
241 };
242 
243 /* helper function to track stats about max rto and related transport */
244 static inline void sctp_max_rto(struct sctp_association *asoc,
245 				struct sctp_transport *trans)
246 {
247 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
248 		asoc->stats.max_obs_rto = trans->rto;
249 		memset(&asoc->stats.obs_rto_ipaddr, 0,
250 			sizeof(struct sockaddr_storage));
251 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
252 			trans->af_specific->sockaddr_len);
253 	}
254 }
255 
256 /*
257  * Macros for keeping a global reference of object allocations.
258  */
259 #ifdef CONFIG_SCTP_DBG_OBJCNT
260 
261 extern atomic_t sctp_dbg_objcnt_sock;
262 extern atomic_t sctp_dbg_objcnt_ep;
263 extern atomic_t sctp_dbg_objcnt_assoc;
264 extern atomic_t sctp_dbg_objcnt_transport;
265 extern atomic_t sctp_dbg_objcnt_chunk;
266 extern atomic_t sctp_dbg_objcnt_bind_addr;
267 extern atomic_t sctp_dbg_objcnt_bind_bucket;
268 extern atomic_t sctp_dbg_objcnt_addr;
269 extern atomic_t sctp_dbg_objcnt_ssnmap;
270 extern atomic_t sctp_dbg_objcnt_datamsg;
271 extern atomic_t sctp_dbg_objcnt_keys;
272 
273 /* Macros to atomically increment/decrement objcnt counters.  */
274 #define SCTP_DBG_OBJCNT_INC(name) \
275 atomic_inc(&sctp_dbg_objcnt_## name)
276 #define SCTP_DBG_OBJCNT_DEC(name) \
277 atomic_dec(&sctp_dbg_objcnt_## name)
278 #define SCTP_DBG_OBJCNT(name) \
279 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
280 
281 /* Macro to help create new entries in in the global array of
282  * objcnt counters.
283  */
284 #define SCTP_DBG_OBJCNT_ENTRY(name) \
285 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
286 
287 void sctp_dbg_objcnt_init(struct net *);
288 void sctp_dbg_objcnt_exit(struct net *);
289 
290 #else
291 
292 #define SCTP_DBG_OBJCNT_INC(name)
293 #define SCTP_DBG_OBJCNT_DEC(name)
294 
295 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
296 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
297 
298 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
299 
300 #if defined CONFIG_SYSCTL
301 void sctp_sysctl_register(void);
302 void sctp_sysctl_unregister(void);
303 int sctp_sysctl_net_register(struct net *net);
304 void sctp_sysctl_net_unregister(struct net *net);
305 #else
306 static inline void sctp_sysctl_register(void) { return; }
307 static inline void sctp_sysctl_unregister(void) { return; }
308 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
309 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
310 #endif
311 
312 /* Size of Supported Address Parameter for 'x' address types. */
313 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
314 
315 #if IS_ENABLED(CONFIG_IPV6)
316 
317 void sctp_v6_pf_init(void);
318 void sctp_v6_pf_exit(void);
319 int sctp_v6_protosw_init(void);
320 void sctp_v6_protosw_exit(void);
321 int sctp_v6_add_protocol(void);
322 void sctp_v6_del_protocol(void);
323 
324 #else /* #ifdef defined(CONFIG_IPV6) */
325 
326 static inline void sctp_v6_pf_init(void) { return; }
327 static inline void sctp_v6_pf_exit(void) { return; }
328 static inline int sctp_v6_protosw_init(void) { return 0; }
329 static inline void sctp_v6_protosw_exit(void) { return; }
330 static inline int sctp_v6_add_protocol(void) { return 0; }
331 static inline void sctp_v6_del_protocol(void) { return; }
332 
333 #endif /* #if defined(CONFIG_IPV6) */
334 
335 
336 /* Map an association to an assoc_id. */
337 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
338 {
339 	return asoc ? asoc->assoc_id : 0;
340 }
341 
342 /* Look up the association by its id.  */
343 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
344 
345 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
346 
347 /* A macro to walk a list of skbs.  */
348 #define sctp_skb_for_each(pos, head, tmp) \
349 	skb_queue_walk_safe(head, pos, tmp)
350 
351 /* A helper to append an entire skb list (list) to another (head). */
352 static inline void sctp_skb_list_tail(struct sk_buff_head *list,
353 				      struct sk_buff_head *head)
354 {
355 	unsigned long flags;
356 
357 	sctp_spin_lock_irqsave(&head->lock, flags);
358 	sctp_spin_lock(&list->lock);
359 
360 	skb_queue_splice_tail_init(list, head);
361 
362 	sctp_spin_unlock(&list->lock);
363 	sctp_spin_unlock_irqrestore(&head->lock, flags);
364 }
365 
366 /**
367  *	sctp_list_dequeue - remove from the head of the queue
368  *	@list: list to dequeue from
369  *
370  *	Remove the head of the list. The head item is
371  *	returned or %NULL if the list is empty.
372  */
373 
374 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
375 {
376 	struct list_head *result = NULL;
377 
378 	if (list->next != list) {
379 		result = list->next;
380 		list->next = result->next;
381 		list->next->prev = list;
382 		INIT_LIST_HEAD(result);
383 	}
384 	return result;
385 }
386 
387 /* SCTP version of skb_set_owner_r.  We need this one because
388  * of the way we have to do receive buffer accounting on bundled
389  * chunks.
390  */
391 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
392 {
393 	struct sctp_ulpevent *event = sctp_skb2event(skb);
394 
395 	skb_orphan(skb);
396 	skb->sk = sk;
397 	skb->destructor = sctp_sock_rfree;
398 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
399 	/*
400 	 * This mimics the behavior of skb_set_owner_r
401 	 */
402 	sk->sk_forward_alloc -= event->rmem_len;
403 }
404 
405 /* Tests if the list has one and only one entry. */
406 static inline int sctp_list_single_entry(struct list_head *head)
407 {
408 	return (head->next != head) && (head->next == head->prev);
409 }
410 
411 /* Generate a random jitter in the range of -50% ~ +50% of input RTO. */
412 static inline __s32 sctp_jitter(__u32 rto)
413 {
414 	static __u32 sctp_rand;
415 	__s32 ret;
416 
417 	/* Avoid divide by zero. */
418 	if (!rto)
419 		rto = 1;
420 
421 	sctp_rand += jiffies;
422 	sctp_rand ^= (sctp_rand << 12);
423 	sctp_rand ^= (sctp_rand >> 20);
424 
425 	/* Choose random number from 0 to rto, then move to -50% ~ +50%
426 	 * of rto.
427 	 */
428 	ret = sctp_rand % rto - (rto >> 1);
429 	return ret;
430 }
431 
432 /* Break down data chunks at this point.  */
433 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
434 {
435 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
436 	int frag = pmtu;
437 
438 	frag -= sp->pf->af->net_header_len;
439 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
440 
441 	if (asoc->user_frag)
442 		frag = min_t(int, frag, asoc->user_frag);
443 
444 	frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);
445 
446 	return frag;
447 }
448 
449 static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
450 {
451 
452 	sctp_assoc_sync_pmtu(sk, asoc);
453 	asoc->pmtu_pending = 0;
454 }
455 
456 /* Walk through a list of TLV parameters.  Don't trust the
457  * individual parameter lengths and instead depend on
458  * the chunk length to indicate when to stop.  Make sure
459  * there is room for a param header too.
460  */
461 #define sctp_walk_params(pos, chunk, member)\
462 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
463 
464 #define _sctp_walk_params(pos, chunk, end, member)\
465 for (pos.v = chunk->member;\
466      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
467      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
468      pos.v += WORD_ROUND(ntohs(pos.p->length)))
469 
470 #define sctp_walk_errors(err, chunk_hdr)\
471 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
472 
473 #define _sctp_walk_errors(err, chunk_hdr, end)\
474 for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
475 	    sizeof(sctp_chunkhdr_t));\
476      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
477      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
478      err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
479 
480 #define sctp_walk_fwdtsn(pos, chunk)\
481 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
482 
483 #define _sctp_walk_fwdtsn(pos, chunk, end)\
484 for (pos = chunk->subh.fwdtsn_hdr->skip;\
485      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
486      pos++)
487 
488 /* Round an int up to the next multiple of 4.  */
489 #define WORD_ROUND(s) (((s)+3)&~3)
490 
491 /* External references. */
492 
493 extern struct proto sctp_prot;
494 extern struct proto sctpv6_prot;
495 void sctp_put_port(struct sock *sk);
496 
497 extern struct idr sctp_assocs_id;
498 extern spinlock_t sctp_assocs_id_lock;
499 
500 /* Static inline functions. */
501 
502 /* Convert from an IP version number to an Address Family symbol.  */
503 static inline int ipver2af(__u8 ipver)
504 {
505 	switch (ipver) {
506 	case 4:
507 	        return  AF_INET;
508 	case 6:
509 		return AF_INET6;
510 	default:
511 		return 0;
512 	}
513 }
514 
515 /* Convert from an address parameter type to an address family.  */
516 static inline int param_type2af(__be16 type)
517 {
518 	switch (type) {
519 	case SCTP_PARAM_IPV4_ADDRESS:
520 	        return  AF_INET;
521 	case SCTP_PARAM_IPV6_ADDRESS:
522 		return AF_INET6;
523 	default:
524 		return 0;
525 	}
526 }
527 
528 /* Warning: The following hash functions assume a power of two 'size'. */
529 /* This is the hash function for the SCTP port hash table. */
530 static inline int sctp_phashfn(struct net *net, __u16 lport)
531 {
532 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
533 }
534 
535 /* This is the hash function for the endpoint hash table. */
536 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
537 {
538 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
539 }
540 
541 /* This is the hash function for the association hash table. */
542 static inline int sctp_assoc_hashfn(struct net *net, __u16 lport, __u16 rport)
543 {
544 	int h = (lport << 16) + rport + net_hash_mix(net);
545 	h ^= h>>8;
546 	return h & (sctp_assoc_hashsize - 1);
547 }
548 
549 /* This is the hash function for the association hash table.  This is
550  * not used yet, but could be used as a better hash function when
551  * we have a vtag.
552  */
553 static inline int sctp_vtag_hashfn(__u16 lport, __u16 rport, __u32 vtag)
554 {
555 	int h = (lport << 16) + rport;
556 	h ^= vtag;
557 	return h & (sctp_assoc_hashsize - 1);
558 }
559 
560 #define sctp_for_each_hentry(epb, head) \
561 	hlist_for_each_entry(epb, head, node)
562 
563 /* Is a socket of this style? */
564 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
565 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
566 {
567 	return sctp_sk(sk)->type == style;
568 }
569 
570 /* Is the association in this state? */
571 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
572 static inline int __sctp_state(const struct sctp_association *asoc,
573 			       sctp_state_t state)
574 {
575 	return asoc->state == state;
576 }
577 
578 /* Is the socket in this state? */
579 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
580 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
581 {
582 	return sk->sk_state == state;
583 }
584 
585 /* Map v4-mapped v6 address back to v4 address */
586 static inline void sctp_v6_map_v4(union sctp_addr *addr)
587 {
588 	addr->v4.sin_family = AF_INET;
589 	addr->v4.sin_port = addr->v6.sin6_port;
590 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
591 }
592 
593 /* Map v4 address to v4-mapped v6 address */
594 static inline void sctp_v4_map_v6(union sctp_addr *addr)
595 {
596 	addr->v6.sin6_family = AF_INET6;
597 	addr->v6.sin6_port = addr->v4.sin_port;
598 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
599 	addr->v6.sin6_addr.s6_addr32[0] = 0;
600 	addr->v6.sin6_addr.s6_addr32[1] = 0;
601 	addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
602 }
603 
604 /* The cookie is always 0 since this is how it's used in the
605  * pmtu code.
606  */
607 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
608 {
609 	if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
610 		dst_release(t->dst);
611 		t->dst = NULL;
612 	}
613 
614 	return t->dst;
615 }
616 
617 #endif /* __net_sctp_h__ */
618