xref: /openbmc/linux/include/net/sctp/sctp.h (revision ee8a99bd)
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 <lksctp-developers@lists.sourceforge.net>
31  *
32  * Or submit a bug report through the following website:
33  *    http://www.sf.net/projects/lksctp
34  *
35  * Written or modified by:
36  *    La Monte H.P. Yarroll <piggy@acm.org>
37  *    Xingang Guo           <xingang.guo@intel.com>
38  *    Jon Grimm             <jgrimm@us.ibm.com>
39  *    Daisy Chang           <daisyc@us.ibm.com>
40  *    Sridhar Samudrala     <sri@us.ibm.com>
41  *    Ardelle Fan           <ardelle.fan@intel.com>
42  *    Ryan Layer            <rmlayer@us.ibm.com>
43  *    Kevin Gao             <kevin.gao@intel.com>
44  *
45  * Any bugs reported given to us we will try to fix... any fixes shared will
46  * be incorporated into the next SCTP release.
47  */
48 
49 #ifndef __net_sctp_h__
50 #define __net_sctp_h__
51 
52 /* Header Strategy.
53  *    Start getting some control over the header file depencies:
54  *       includes
55  *       constants
56  *       structs
57  *       prototypes
58  *       macros, externs, and inlines
59  *
60  *   Move test_frame specific items out of the kernel headers
61  *   and into the test frame headers.   This is not perfect in any sense
62  *   and will continue to evolve.
63  */
64 
65 #include <linux/types.h>
66 #include <linux/slab.h>
67 #include <linux/in.h>
68 #include <linux/tty.h>
69 #include <linux/proc_fs.h>
70 #include <linux/spinlock.h>
71 #include <linux/jiffies.h>
72 #include <linux/idr.h>
73 
74 #if IS_ENABLED(CONFIG_IPV6)
75 #include <net/ipv6.h>
76 #include <net/ip6_route.h>
77 #endif
78 
79 #include <asm/uaccess.h>
80 #include <asm/page.h>
81 #include <net/sock.h>
82 #include <net/snmp.h>
83 #include <net/sctp/structs.h>
84 #include <net/sctp/constants.h>
85 
86 #ifdef CONFIG_IP_SCTP_MODULE
87 #define SCTP_PROTOSW_FLAG 0
88 #else /* static! */
89 #define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
90 #endif
91 
92 /*
93  * Function declarations.
94  */
95 
96 /*
97  * sctp/protocol.c
98  */
99 extern int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
100 				     sctp_scope_t, gfp_t gfp,
101 				     int flags);
102 extern struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
103 extern int sctp_register_pf(struct sctp_pf *, sa_family_t);
104 extern void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
105 
106 /*
107  * sctp/socket.c
108  */
109 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
110 int sctp_inet_listen(struct socket *sock, int backlog);
111 void sctp_write_space(struct sock *sk);
112 void sctp_data_ready(struct sock *sk, int len);
113 unsigned int sctp_poll(struct file *file, struct socket *sock,
114 		poll_table *wait);
115 void sctp_sock_rfree(struct sk_buff *skb);
116 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
117 		    struct sctp_association *asoc);
118 extern struct percpu_counter sctp_sockets_allocated;
119 extern int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
120 
121 /*
122  * sctp/primitive.c
123  */
124 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
125 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
126 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
127 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
128 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
129 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
130 
131 /*
132  * sctp/input.c
133  */
134 int sctp_rcv(struct sk_buff *skb);
135 void sctp_v4_err(struct sk_buff *skb, u32 info);
136 void sctp_hash_established(struct sctp_association *);
137 void sctp_unhash_established(struct sctp_association *);
138 void sctp_hash_endpoint(struct sctp_endpoint *);
139 void sctp_unhash_endpoint(struct sctp_endpoint *);
140 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
141 			     struct sctphdr *, struct sctp_association **,
142 			     struct sctp_transport **);
143 void sctp_err_finish(struct sock *, struct sctp_association *);
144 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
145 			   struct sctp_transport *t, __u32 pmtu);
146 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
147 			struct sk_buff *);
148 void sctp_icmp_proto_unreachable(struct sock *sk,
149 				 struct sctp_association *asoc,
150 				 struct sctp_transport *t);
151 void sctp_backlog_migrate(struct sctp_association *assoc,
152 			  struct sock *oldsk, struct sock *newsk);
153 
154 /*
155  * sctp/proc.c
156  */
157 int sctp_snmp_proc_init(struct net *net);
158 void sctp_snmp_proc_exit(struct net *net);
159 int sctp_eps_proc_init(struct net *net);
160 void sctp_eps_proc_exit(struct net *net);
161 int sctp_assocs_proc_init(struct net *net);
162 void sctp_assocs_proc_exit(struct net *net);
163 int sctp_remaddr_proc_init(struct net *net);
164 void sctp_remaddr_proc_exit(struct net *net);
165 
166 
167 /*
168  * Module global variables
169  */
170 
171  /*
172   * sctp/protocol.c
173   */
174 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
175 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
176 
177 /*
178  *  Section:  Macros, externs, and inlines
179  */
180 
181 /* spin lock wrappers. */
182 #define sctp_spin_lock_irqsave(lock, flags) spin_lock_irqsave(lock, flags)
183 #define sctp_spin_unlock_irqrestore(lock, flags)  \
184        spin_unlock_irqrestore(lock, flags)
185 #define sctp_local_bh_disable() local_bh_disable()
186 #define sctp_local_bh_enable()  local_bh_enable()
187 #define sctp_spin_lock(lock)    spin_lock(lock)
188 #define sctp_spin_unlock(lock)  spin_unlock(lock)
189 #define sctp_write_lock(lock)   write_lock(lock)
190 #define sctp_write_unlock(lock) write_unlock(lock)
191 #define sctp_read_lock(lock)    read_lock(lock)
192 #define sctp_read_unlock(lock)  read_unlock(lock)
193 
194 /* sock lock wrappers. */
195 #define sctp_lock_sock(sk)       lock_sock(sk)
196 #define sctp_release_sock(sk)    release_sock(sk)
197 #define sctp_bh_lock_sock(sk)    bh_lock_sock(sk)
198 #define sctp_bh_unlock_sock(sk)  bh_unlock_sock(sk)
199 
200 /* SCTP SNMP MIB stats handlers */
201 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
202 #define SCTP_INC_STATS_BH(net, field)   SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
203 #define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
204 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
205 
206 /* sctp mib definitions */
207 enum {
208 	SCTP_MIB_NUM = 0,
209 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
210 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
211 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
212 	SCTP_MIB_ABORTEDS,			/* Aborteds */
213 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
214 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
215 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
216 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
217 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
218 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
219 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
220 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
221 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
222 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
223 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
224 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
225 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
226 	SCTP_MIB_T1_INIT_EXPIREDS,
227 	SCTP_MIB_T1_COOKIE_EXPIREDS,
228 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
229 	SCTP_MIB_T3_RTX_EXPIREDS,
230 	SCTP_MIB_T4_RTO_EXPIREDS,
231 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
232 	SCTP_MIB_DELAY_SACK_EXPIREDS,
233 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
234 	SCTP_MIB_T1_RETRANSMITS,
235 	SCTP_MIB_T3_RETRANSMITS,
236 	SCTP_MIB_PMTUD_RETRANSMITS,
237 	SCTP_MIB_FAST_RETRANSMITS,
238 	SCTP_MIB_IN_PKT_SOFTIRQ,
239 	SCTP_MIB_IN_PKT_BACKLOG,
240 	SCTP_MIB_IN_PKT_DISCARDS,
241 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
242 	__SCTP_MIB_MAX
243 };
244 
245 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
246 struct sctp_mib {
247         unsigned long   mibs[SCTP_MIB_MAX];
248 };
249 
250 /* helper function to track stats about max rto and related transport */
251 static inline void sctp_max_rto(struct sctp_association *asoc,
252 				struct sctp_transport *trans)
253 {
254 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
255 		asoc->stats.max_obs_rto = trans->rto;
256 		memset(&asoc->stats.obs_rto_ipaddr, 0,
257 			sizeof(struct sockaddr_storage));
258 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
259 			trans->af_specific->sockaddr_len);
260 	}
261 }
262 
263 /*
264  * Macros for keeping a global reference of object allocations.
265  */
266 #ifdef CONFIG_SCTP_DBG_OBJCNT
267 
268 extern atomic_t sctp_dbg_objcnt_sock;
269 extern atomic_t sctp_dbg_objcnt_ep;
270 extern atomic_t sctp_dbg_objcnt_assoc;
271 extern atomic_t sctp_dbg_objcnt_transport;
272 extern atomic_t sctp_dbg_objcnt_chunk;
273 extern atomic_t sctp_dbg_objcnt_bind_addr;
274 extern atomic_t sctp_dbg_objcnt_bind_bucket;
275 extern atomic_t sctp_dbg_objcnt_addr;
276 extern atomic_t sctp_dbg_objcnt_ssnmap;
277 extern atomic_t sctp_dbg_objcnt_datamsg;
278 extern atomic_t sctp_dbg_objcnt_keys;
279 
280 /* Macros to atomically increment/decrement objcnt counters.  */
281 #define SCTP_DBG_OBJCNT_INC(name) \
282 atomic_inc(&sctp_dbg_objcnt_## name)
283 #define SCTP_DBG_OBJCNT_DEC(name) \
284 atomic_dec(&sctp_dbg_objcnt_## name)
285 #define SCTP_DBG_OBJCNT(name) \
286 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
287 
288 /* Macro to help create new entries in in the global array of
289  * objcnt counters.
290  */
291 #define SCTP_DBG_OBJCNT_ENTRY(name) \
292 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
293 
294 void sctp_dbg_objcnt_init(struct net *);
295 void sctp_dbg_objcnt_exit(struct net *);
296 
297 #else
298 
299 #define SCTP_DBG_OBJCNT_INC(name)
300 #define SCTP_DBG_OBJCNT_DEC(name)
301 
302 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
303 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
304 
305 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
306 
307 #if defined CONFIG_SYSCTL
308 void sctp_sysctl_register(void);
309 void sctp_sysctl_unregister(void);
310 int sctp_sysctl_net_register(struct net *net);
311 void sctp_sysctl_net_unregister(struct net *net);
312 #else
313 static inline void sctp_sysctl_register(void) { return; }
314 static inline void sctp_sysctl_unregister(void) { return; }
315 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
316 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
317 #endif
318 
319 /* Size of Supported Address Parameter for 'x' address types. */
320 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
321 
322 #if IS_ENABLED(CONFIG_IPV6)
323 
324 void sctp_v6_pf_init(void);
325 void sctp_v6_pf_exit(void);
326 int sctp_v6_protosw_init(void);
327 void sctp_v6_protosw_exit(void);
328 int sctp_v6_add_protocol(void);
329 void sctp_v6_del_protocol(void);
330 
331 #else /* #ifdef defined(CONFIG_IPV6) */
332 
333 static inline void sctp_v6_pf_init(void) { return; }
334 static inline void sctp_v6_pf_exit(void) { return; }
335 static inline int sctp_v6_protosw_init(void) { return 0; }
336 static inline void sctp_v6_protosw_exit(void) { return; }
337 static inline int sctp_v6_add_protocol(void) { return 0; }
338 static inline void sctp_v6_del_protocol(void) { return; }
339 
340 #endif /* #if defined(CONFIG_IPV6) */
341 
342 
343 /* Map an association to an assoc_id. */
344 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
345 {
346 	return asoc ? asoc->assoc_id : 0;
347 }
348 
349 /* Look up the association by its id.  */
350 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
351 
352 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
353 
354 /* A macro to walk a list of skbs.  */
355 #define sctp_skb_for_each(pos, head, tmp) \
356 	skb_queue_walk_safe(head, pos, tmp)
357 
358 /* A helper to append an entire skb list (list) to another (head). */
359 static inline void sctp_skb_list_tail(struct sk_buff_head *list,
360 				      struct sk_buff_head *head)
361 {
362 	unsigned long flags;
363 
364 	sctp_spin_lock_irqsave(&head->lock, flags);
365 	sctp_spin_lock(&list->lock);
366 
367 	skb_queue_splice_tail_init(list, head);
368 
369 	sctp_spin_unlock(&list->lock);
370 	sctp_spin_unlock_irqrestore(&head->lock, flags);
371 }
372 
373 /**
374  *	sctp_list_dequeue - remove from the head of the queue
375  *	@list: list to dequeue from
376  *
377  *	Remove the head of the list. The head item is
378  *	returned or %NULL if the list is empty.
379  */
380 
381 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
382 {
383 	struct list_head *result = NULL;
384 
385 	if (list->next != list) {
386 		result = list->next;
387 		list->next = result->next;
388 		list->next->prev = list;
389 		INIT_LIST_HEAD(result);
390 	}
391 	return result;
392 }
393 
394 /* SCTP version of skb_set_owner_r.  We need this one because
395  * of the way we have to do receive buffer accounting on bundled
396  * chunks.
397  */
398 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
399 {
400 	struct sctp_ulpevent *event = sctp_skb2event(skb);
401 
402 	skb_orphan(skb);
403 	skb->sk = sk;
404 	skb->destructor = sctp_sock_rfree;
405 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
406 	/*
407 	 * This mimics the behavior of skb_set_owner_r
408 	 */
409 	sk->sk_forward_alloc -= event->rmem_len;
410 }
411 
412 /* Tests if the list has one and only one entry. */
413 static inline int sctp_list_single_entry(struct list_head *head)
414 {
415 	return (head->next != head) && (head->next == head->prev);
416 }
417 
418 /* Generate a random jitter in the range of -50% ~ +50% of input RTO. */
419 static inline __s32 sctp_jitter(__u32 rto)
420 {
421 	static __u32 sctp_rand;
422 	__s32 ret;
423 
424 	/* Avoid divide by zero. */
425 	if (!rto)
426 		rto = 1;
427 
428 	sctp_rand += jiffies;
429 	sctp_rand ^= (sctp_rand << 12);
430 	sctp_rand ^= (sctp_rand >> 20);
431 
432 	/* Choose random number from 0 to rto, then move to -50% ~ +50%
433 	 * of rto.
434 	 */
435 	ret = sctp_rand % rto - (rto >> 1);
436 	return ret;
437 }
438 
439 /* Break down data chunks at this point.  */
440 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
441 {
442 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
443 	int frag = pmtu;
444 
445 	frag -= sp->pf->af->net_header_len;
446 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
447 
448 	if (asoc->user_frag)
449 		frag = min_t(int, frag, asoc->user_frag);
450 
451 	frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);
452 
453 	return frag;
454 }
455 
456 static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
457 {
458 
459 	sctp_assoc_sync_pmtu(sk, asoc);
460 	asoc->pmtu_pending = 0;
461 }
462 
463 /* Walk through a list of TLV parameters.  Don't trust the
464  * individual parameter lengths and instead depend on
465  * the chunk length to indicate when to stop.  Make sure
466  * there is room for a param header too.
467  */
468 #define sctp_walk_params(pos, chunk, member)\
469 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
470 
471 #define _sctp_walk_params(pos, chunk, end, member)\
472 for (pos.v = chunk->member;\
473      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
474      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
475      pos.v += WORD_ROUND(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 = (sctp_errhdr_t *)((void *)chunk_hdr + \
482 	    sizeof(sctp_chunkhdr_t));\
483      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
484      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
485      err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
486 
487 #define sctp_walk_fwdtsn(pos, chunk)\
488 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
489 
490 #define _sctp_walk_fwdtsn(pos, chunk, end)\
491 for (pos = chunk->subh.fwdtsn_hdr->skip;\
492      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
493      pos++)
494 
495 /* Round an int up to the next multiple of 4.  */
496 #define WORD_ROUND(s) (((s)+3)&~3)
497 
498 /* External references. */
499 
500 extern struct proto sctp_prot;
501 extern struct proto sctpv6_prot;
502 void sctp_put_port(struct sock *sk);
503 
504 extern struct idr sctp_assocs_id;
505 extern spinlock_t sctp_assocs_id_lock;
506 
507 /* Static inline functions. */
508 
509 /* Convert from an IP version number to an Address Family symbol.  */
510 static inline int ipver2af(__u8 ipver)
511 {
512 	switch (ipver) {
513 	case 4:
514 	        return  AF_INET;
515 	case 6:
516 		return AF_INET6;
517 	default:
518 		return 0;
519 	}
520 }
521 
522 /* Convert from an address parameter type to an address family.  */
523 static inline int param_type2af(__be16 type)
524 {
525 	switch (type) {
526 	case SCTP_PARAM_IPV4_ADDRESS:
527 	        return  AF_INET;
528 	case SCTP_PARAM_IPV6_ADDRESS:
529 		return AF_INET6;
530 	default:
531 		return 0;
532 	}
533 }
534 
535 /* Warning: The following hash functions assume a power of two 'size'. */
536 /* This is the hash function for the SCTP port hash table. */
537 static inline int sctp_phashfn(struct net *net, __u16 lport)
538 {
539 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
540 }
541 
542 /* This is the hash function for the endpoint hash table. */
543 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
544 {
545 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
546 }
547 
548 /* This is the hash function for the association hash table. */
549 static inline int sctp_assoc_hashfn(struct net *net, __u16 lport, __u16 rport)
550 {
551 	int h = (lport << 16) + rport + net_hash_mix(net);
552 	h ^= h>>8;
553 	return h & (sctp_assoc_hashsize - 1);
554 }
555 
556 /* This is the hash function for the association hash table.  This is
557  * not used yet, but could be used as a better hash function when
558  * we have a vtag.
559  */
560 static inline int sctp_vtag_hashfn(__u16 lport, __u16 rport, __u32 vtag)
561 {
562 	int h = (lport << 16) + rport;
563 	h ^= vtag;
564 	return h & (sctp_assoc_hashsize - 1);
565 }
566 
567 #define sctp_for_each_hentry(epb, head) \
568 	hlist_for_each_entry(epb, head, node)
569 
570 /* Is a socket of this style? */
571 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
572 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
573 {
574 	return sctp_sk(sk)->type == style;
575 }
576 
577 /* Is the association in this state? */
578 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
579 static inline int __sctp_state(const struct sctp_association *asoc,
580 			       sctp_state_t state)
581 {
582 	return asoc->state == state;
583 }
584 
585 /* Is the socket in this state? */
586 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
587 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
588 {
589 	return sk->sk_state == state;
590 }
591 
592 /* Map v4-mapped v6 address back to v4 address */
593 static inline void sctp_v6_map_v4(union sctp_addr *addr)
594 {
595 	addr->v4.sin_family = AF_INET;
596 	addr->v4.sin_port = addr->v6.sin6_port;
597 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
598 }
599 
600 /* Map v4 address to v4-mapped v6 address */
601 static inline void sctp_v4_map_v6(union sctp_addr *addr)
602 {
603 	addr->v6.sin6_family = AF_INET6;
604 	addr->v6.sin6_port = addr->v4.sin_port;
605 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
606 	addr->v6.sin6_addr.s6_addr32[0] = 0;
607 	addr->v6.sin6_addr.s6_addr32[1] = 0;
608 	addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
609 }
610 
611 /* The cookie is always 0 since this is how it's used in the
612  * pmtu code.
613  */
614 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
615 {
616 	if (t->dst && !dst_check(t->dst, 0)) {
617 		dst_release(t->dst);
618 		t->dst = NULL;
619 	}
620 
621 	return t->dst;
622 }
623 
624 #endif /* __net_sctp_h__ */
625