xref: /openbmc/linux/include/net/sctp/sctp.h (revision 5bd8e16d)
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 extern int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
94 				     sctp_scope_t, gfp_t gfp,
95 				     int flags);
96 extern struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
97 extern int sctp_register_pf(struct sctp_pf *, sa_family_t);
98 extern void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
99 
100 /*
101  * sctp/socket.c
102  */
103 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
104 int sctp_inet_listen(struct socket *sock, int backlog);
105 void sctp_write_space(struct sock *sk);
106 void sctp_data_ready(struct sock *sk, int len);
107 unsigned int sctp_poll(struct file *file, struct socket *sock,
108 		poll_table *wait);
109 void sctp_sock_rfree(struct sk_buff *skb);
110 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
111 		    struct sctp_association *asoc);
112 extern struct percpu_counter sctp_sockets_allocated;
113 extern int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
114 
115 /*
116  * sctp/primitive.c
117  */
118 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
119 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
120 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
121 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
122 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
123 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
124 
125 /*
126  * sctp/input.c
127  */
128 int sctp_rcv(struct sk_buff *skb);
129 void sctp_v4_err(struct sk_buff *skb, u32 info);
130 void sctp_hash_established(struct sctp_association *);
131 void sctp_unhash_established(struct sctp_association *);
132 void sctp_hash_endpoint(struct sctp_endpoint *);
133 void sctp_unhash_endpoint(struct sctp_endpoint *);
134 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
135 			     struct sctphdr *, struct sctp_association **,
136 			     struct sctp_transport **);
137 void sctp_err_finish(struct sock *, struct sctp_association *);
138 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
139 			   struct sctp_transport *t, __u32 pmtu);
140 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
141 			struct sk_buff *);
142 void sctp_icmp_proto_unreachable(struct sock *sk,
143 				 struct sctp_association *asoc,
144 				 struct sctp_transport *t);
145 void sctp_backlog_migrate(struct sctp_association *assoc,
146 			  struct sock *oldsk, struct sock *newsk);
147 
148 /*
149  * sctp/proc.c
150  */
151 int sctp_snmp_proc_init(struct net *net);
152 void sctp_snmp_proc_exit(struct net *net);
153 int sctp_eps_proc_init(struct net *net);
154 void sctp_eps_proc_exit(struct net *net);
155 int sctp_assocs_proc_init(struct net *net);
156 void sctp_assocs_proc_exit(struct net *net);
157 int sctp_remaddr_proc_init(struct net *net);
158 void sctp_remaddr_proc_exit(struct net *net);
159 
160 
161 /*
162  * Module global variables
163  */
164 
165  /*
166   * sctp/protocol.c
167   */
168 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
169 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
170 
171 /*
172  *  Section:  Macros, externs, and inlines
173  */
174 
175 /* spin lock wrappers. */
176 #define sctp_spin_lock_irqsave(lock, flags) spin_lock_irqsave(lock, flags)
177 #define sctp_spin_unlock_irqrestore(lock, flags)  \
178        spin_unlock_irqrestore(lock, flags)
179 #define sctp_local_bh_disable() local_bh_disable()
180 #define sctp_local_bh_enable()  local_bh_enable()
181 #define sctp_spin_lock(lock)    spin_lock(lock)
182 #define sctp_spin_unlock(lock)  spin_unlock(lock)
183 #define sctp_write_lock(lock)   write_lock(lock)
184 #define sctp_write_unlock(lock) write_unlock(lock)
185 #define sctp_read_lock(lock)    read_lock(lock)
186 #define sctp_read_unlock(lock)  read_unlock(lock)
187 
188 /* sock lock wrappers. */
189 #define sctp_lock_sock(sk)       lock_sock(sk)
190 #define sctp_release_sock(sk)    release_sock(sk)
191 #define sctp_bh_lock_sock(sk)    bh_lock_sock(sk)
192 #define sctp_bh_unlock_sock(sk)  bh_unlock_sock(sk)
193 
194 /* SCTP SNMP MIB stats handlers */
195 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
196 #define SCTP_INC_STATS_BH(net, field)   SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
197 #define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
198 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
199 
200 /* sctp mib definitions */
201 enum {
202 	SCTP_MIB_NUM = 0,
203 	SCTP_MIB_CURRESTAB,			/* CurrEstab */
204 	SCTP_MIB_ACTIVEESTABS,			/* ActiveEstabs */
205 	SCTP_MIB_PASSIVEESTABS,			/* PassiveEstabs */
206 	SCTP_MIB_ABORTEDS,			/* Aborteds */
207 	SCTP_MIB_SHUTDOWNS,			/* Shutdowns */
208 	SCTP_MIB_OUTOFBLUES,			/* OutOfBlues */
209 	SCTP_MIB_CHECKSUMERRORS,		/* ChecksumErrors */
210 	SCTP_MIB_OUTCTRLCHUNKS,			/* OutCtrlChunks */
211 	SCTP_MIB_OUTORDERCHUNKS,		/* OutOrderChunks */
212 	SCTP_MIB_OUTUNORDERCHUNKS,		/* OutUnorderChunks */
213 	SCTP_MIB_INCTRLCHUNKS,			/* InCtrlChunks */
214 	SCTP_MIB_INORDERCHUNKS,			/* InOrderChunks */
215 	SCTP_MIB_INUNORDERCHUNKS,		/* InUnorderChunks */
216 	SCTP_MIB_FRAGUSRMSGS,			/* FragUsrMsgs */
217 	SCTP_MIB_REASMUSRMSGS,			/* ReasmUsrMsgs */
218 	SCTP_MIB_OUTSCTPPACKS,			/* OutSCTPPacks */
219 	SCTP_MIB_INSCTPPACKS,			/* InSCTPPacks */
220 	SCTP_MIB_T1_INIT_EXPIREDS,
221 	SCTP_MIB_T1_COOKIE_EXPIREDS,
222 	SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
223 	SCTP_MIB_T3_RTX_EXPIREDS,
224 	SCTP_MIB_T4_RTO_EXPIREDS,
225 	SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
226 	SCTP_MIB_DELAY_SACK_EXPIREDS,
227 	SCTP_MIB_AUTOCLOSE_EXPIREDS,
228 	SCTP_MIB_T1_RETRANSMITS,
229 	SCTP_MIB_T3_RETRANSMITS,
230 	SCTP_MIB_PMTUD_RETRANSMITS,
231 	SCTP_MIB_FAST_RETRANSMITS,
232 	SCTP_MIB_IN_PKT_SOFTIRQ,
233 	SCTP_MIB_IN_PKT_BACKLOG,
234 	SCTP_MIB_IN_PKT_DISCARDS,
235 	SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
236 	__SCTP_MIB_MAX
237 };
238 
239 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
240 struct sctp_mib {
241         unsigned long   mibs[SCTP_MIB_MAX];
242 };
243 
244 /* helper function to track stats about max rto and related transport */
245 static inline void sctp_max_rto(struct sctp_association *asoc,
246 				struct sctp_transport *trans)
247 {
248 	if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
249 		asoc->stats.max_obs_rto = trans->rto;
250 		memset(&asoc->stats.obs_rto_ipaddr, 0,
251 			sizeof(struct sockaddr_storage));
252 		memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
253 			trans->af_specific->sockaddr_len);
254 	}
255 }
256 
257 /*
258  * Macros for keeping a global reference of object allocations.
259  */
260 #ifdef CONFIG_SCTP_DBG_OBJCNT
261 
262 extern atomic_t sctp_dbg_objcnt_sock;
263 extern atomic_t sctp_dbg_objcnt_ep;
264 extern atomic_t sctp_dbg_objcnt_assoc;
265 extern atomic_t sctp_dbg_objcnt_transport;
266 extern atomic_t sctp_dbg_objcnt_chunk;
267 extern atomic_t sctp_dbg_objcnt_bind_addr;
268 extern atomic_t sctp_dbg_objcnt_bind_bucket;
269 extern atomic_t sctp_dbg_objcnt_addr;
270 extern atomic_t sctp_dbg_objcnt_ssnmap;
271 extern atomic_t sctp_dbg_objcnt_datamsg;
272 extern atomic_t sctp_dbg_objcnt_keys;
273 
274 /* Macros to atomically increment/decrement objcnt counters.  */
275 #define SCTP_DBG_OBJCNT_INC(name) \
276 atomic_inc(&sctp_dbg_objcnt_## name)
277 #define SCTP_DBG_OBJCNT_DEC(name) \
278 atomic_dec(&sctp_dbg_objcnt_## name)
279 #define SCTP_DBG_OBJCNT(name) \
280 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
281 
282 /* Macro to help create new entries in in the global array of
283  * objcnt counters.
284  */
285 #define SCTP_DBG_OBJCNT_ENTRY(name) \
286 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
287 
288 void sctp_dbg_objcnt_init(struct net *);
289 void sctp_dbg_objcnt_exit(struct net *);
290 
291 #else
292 
293 #define SCTP_DBG_OBJCNT_INC(name)
294 #define SCTP_DBG_OBJCNT_DEC(name)
295 
296 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
297 static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
298 
299 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
300 
301 #if defined CONFIG_SYSCTL
302 void sctp_sysctl_register(void);
303 void sctp_sysctl_unregister(void);
304 int sctp_sysctl_net_register(struct net *net);
305 void sctp_sysctl_net_unregister(struct net *net);
306 #else
307 static inline void sctp_sysctl_register(void) { return; }
308 static inline void sctp_sysctl_unregister(void) { return; }
309 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
310 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
311 #endif
312 
313 /* Size of Supported Address Parameter for 'x' address types. */
314 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
315 
316 #if IS_ENABLED(CONFIG_IPV6)
317 
318 void sctp_v6_pf_init(void);
319 void sctp_v6_pf_exit(void);
320 int sctp_v6_protosw_init(void);
321 void sctp_v6_protosw_exit(void);
322 int sctp_v6_add_protocol(void);
323 void sctp_v6_del_protocol(void);
324 
325 #else /* #ifdef defined(CONFIG_IPV6) */
326 
327 static inline void sctp_v6_pf_init(void) { return; }
328 static inline void sctp_v6_pf_exit(void) { return; }
329 static inline int sctp_v6_protosw_init(void) { return 0; }
330 static inline void sctp_v6_protosw_exit(void) { return; }
331 static inline int sctp_v6_add_protocol(void) { return 0; }
332 static inline void sctp_v6_del_protocol(void) { return; }
333 
334 #endif /* #if defined(CONFIG_IPV6) */
335 
336 
337 /* Map an association to an assoc_id. */
338 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
339 {
340 	return asoc ? asoc->assoc_id : 0;
341 }
342 
343 /* Look up the association by its id.  */
344 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
345 
346 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
347 
348 /* A macro to walk a list of skbs.  */
349 #define sctp_skb_for_each(pos, head, tmp) \
350 	skb_queue_walk_safe(head, pos, tmp)
351 
352 /* A helper to append an entire skb list (list) to another (head). */
353 static inline void sctp_skb_list_tail(struct sk_buff_head *list,
354 				      struct sk_buff_head *head)
355 {
356 	unsigned long flags;
357 
358 	sctp_spin_lock_irqsave(&head->lock, flags);
359 	sctp_spin_lock(&list->lock);
360 
361 	skb_queue_splice_tail_init(list, head);
362 
363 	sctp_spin_unlock(&list->lock);
364 	sctp_spin_unlock_irqrestore(&head->lock, flags);
365 }
366 
367 /**
368  *	sctp_list_dequeue - remove from the head of the queue
369  *	@list: list to dequeue from
370  *
371  *	Remove the head of the list. The head item is
372  *	returned or %NULL if the list is empty.
373  */
374 
375 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
376 {
377 	struct list_head *result = NULL;
378 
379 	if (list->next != list) {
380 		result = list->next;
381 		list->next = result->next;
382 		list->next->prev = list;
383 		INIT_LIST_HEAD(result);
384 	}
385 	return result;
386 }
387 
388 /* SCTP version of skb_set_owner_r.  We need this one because
389  * of the way we have to do receive buffer accounting on bundled
390  * chunks.
391  */
392 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
393 {
394 	struct sctp_ulpevent *event = sctp_skb2event(skb);
395 
396 	skb_orphan(skb);
397 	skb->sk = sk;
398 	skb->destructor = sctp_sock_rfree;
399 	atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
400 	/*
401 	 * This mimics the behavior of skb_set_owner_r
402 	 */
403 	sk->sk_forward_alloc -= event->rmem_len;
404 }
405 
406 /* Tests if the list has one and only one entry. */
407 static inline int sctp_list_single_entry(struct list_head *head)
408 {
409 	return (head->next != head) && (head->next == head->prev);
410 }
411 
412 /* Generate a random jitter in the range of -50% ~ +50% of input RTO. */
413 static inline __s32 sctp_jitter(__u32 rto)
414 {
415 	static __u32 sctp_rand;
416 	__s32 ret;
417 
418 	/* Avoid divide by zero. */
419 	if (!rto)
420 		rto = 1;
421 
422 	sctp_rand += jiffies;
423 	sctp_rand ^= (sctp_rand << 12);
424 	sctp_rand ^= (sctp_rand >> 20);
425 
426 	/* Choose random number from 0 to rto, then move to -50% ~ +50%
427 	 * of rto.
428 	 */
429 	ret = sctp_rand % rto - (rto >> 1);
430 	return ret;
431 }
432 
433 /* Break down data chunks at this point.  */
434 static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
435 {
436 	struct sctp_sock *sp = sctp_sk(asoc->base.sk);
437 	int frag = pmtu;
438 
439 	frag -= sp->pf->af->net_header_len;
440 	frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
441 
442 	if (asoc->user_frag)
443 		frag = min_t(int, frag, asoc->user_frag);
444 
445 	frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);
446 
447 	return frag;
448 }
449 
450 static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
451 {
452 
453 	sctp_assoc_sync_pmtu(sk, asoc);
454 	asoc->pmtu_pending = 0;
455 }
456 
457 /* Walk through a list of TLV parameters.  Don't trust the
458  * individual parameter lengths and instead depend on
459  * the chunk length to indicate when to stop.  Make sure
460  * there is room for a param header too.
461  */
462 #define sctp_walk_params(pos, chunk, member)\
463 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
464 
465 #define _sctp_walk_params(pos, chunk, end, member)\
466 for (pos.v = chunk->member;\
467      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
468      ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
469      pos.v += WORD_ROUND(ntohs(pos.p->length)))
470 
471 #define sctp_walk_errors(err, chunk_hdr)\
472 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
473 
474 #define _sctp_walk_errors(err, chunk_hdr, end)\
475 for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
476 	    sizeof(sctp_chunkhdr_t));\
477      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
478      ntohs(err->length) >= sizeof(sctp_errhdr_t); \
479      err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
480 
481 #define sctp_walk_fwdtsn(pos, chunk)\
482 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
483 
484 #define _sctp_walk_fwdtsn(pos, chunk, end)\
485 for (pos = chunk->subh.fwdtsn_hdr->skip;\
486      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
487      pos++)
488 
489 /* Round an int up to the next multiple of 4.  */
490 #define WORD_ROUND(s) (((s)+3)&~3)
491 
492 /* External references. */
493 
494 extern struct proto sctp_prot;
495 extern struct proto sctpv6_prot;
496 void sctp_put_port(struct sock *sk);
497 
498 extern struct idr sctp_assocs_id;
499 extern spinlock_t sctp_assocs_id_lock;
500 
501 /* Static inline functions. */
502 
503 /* Convert from an IP version number to an Address Family symbol.  */
504 static inline int ipver2af(__u8 ipver)
505 {
506 	switch (ipver) {
507 	case 4:
508 	        return  AF_INET;
509 	case 6:
510 		return AF_INET6;
511 	default:
512 		return 0;
513 	}
514 }
515 
516 /* Convert from an address parameter type to an address family.  */
517 static inline int param_type2af(__be16 type)
518 {
519 	switch (type) {
520 	case SCTP_PARAM_IPV4_ADDRESS:
521 	        return  AF_INET;
522 	case SCTP_PARAM_IPV6_ADDRESS:
523 		return AF_INET6;
524 	default:
525 		return 0;
526 	}
527 }
528 
529 /* Warning: The following hash functions assume a power of two 'size'. */
530 /* This is the hash function for the SCTP port hash table. */
531 static inline int sctp_phashfn(struct net *net, __u16 lport)
532 {
533 	return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
534 }
535 
536 /* This is the hash function for the endpoint hash table. */
537 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
538 {
539 	return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
540 }
541 
542 /* This is the hash function for the association hash table. */
543 static inline int sctp_assoc_hashfn(struct net *net, __u16 lport, __u16 rport)
544 {
545 	int h = (lport << 16) + rport + net_hash_mix(net);
546 	h ^= h>>8;
547 	return h & (sctp_assoc_hashsize - 1);
548 }
549 
550 /* This is the hash function for the association hash table.  This is
551  * not used yet, but could be used as a better hash function when
552  * we have a vtag.
553  */
554 static inline int sctp_vtag_hashfn(__u16 lport, __u16 rport, __u32 vtag)
555 {
556 	int h = (lport << 16) + rport;
557 	h ^= vtag;
558 	return h & (sctp_assoc_hashsize - 1);
559 }
560 
561 #define sctp_for_each_hentry(epb, head) \
562 	hlist_for_each_entry(epb, head, node)
563 
564 /* Is a socket of this style? */
565 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
566 static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
567 {
568 	return sctp_sk(sk)->type == style;
569 }
570 
571 /* Is the association in this state? */
572 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
573 static inline int __sctp_state(const struct sctp_association *asoc,
574 			       sctp_state_t state)
575 {
576 	return asoc->state == state;
577 }
578 
579 /* Is the socket in this state? */
580 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
581 static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
582 {
583 	return sk->sk_state == state;
584 }
585 
586 /* Map v4-mapped v6 address back to v4 address */
587 static inline void sctp_v6_map_v4(union sctp_addr *addr)
588 {
589 	addr->v4.sin_family = AF_INET;
590 	addr->v4.sin_port = addr->v6.sin6_port;
591 	addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
592 }
593 
594 /* Map v4 address to v4-mapped v6 address */
595 static inline void sctp_v4_map_v6(union sctp_addr *addr)
596 {
597 	addr->v6.sin6_family = AF_INET6;
598 	addr->v6.sin6_port = addr->v4.sin_port;
599 	addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
600 	addr->v6.sin6_addr.s6_addr32[0] = 0;
601 	addr->v6.sin6_addr.s6_addr32[1] = 0;
602 	addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
603 }
604 
605 /* The cookie is always 0 since this is how it's used in the
606  * pmtu code.
607  */
608 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
609 {
610 	if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
611 		dst_release(t->dst);
612 		t->dst = NULL;
613 	}
614 
615 	return t->dst;
616 }
617 
618 #endif /* __net_sctp_h__ */
619