xref: /openbmc/linux/include/net/sctp/structs.h (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
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 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * This SCTP implementation is free software;
10  * you can redistribute it and/or modify it under the terms of
11  * the GNU General Public License as published by
12  * the Free Software Foundation; either version 2, or (at your option)
13  * any later version.
14  *
15  * This SCTP implementation is distributed in the hope that it
16  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17  *		   ************************
18  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19  * See the GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with GNU CC; see the file COPYING.  If not, write to
23  * the Free Software Foundation, 59 Temple Place - Suite 330,
24  * Boston, MA 02111-1307, USA.
25  *
26  * Please send any bug reports or fixes you make to the
27  * email addresses:
28  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
29  *
30  * Or submit a bug report through the following website:
31  *    http://www.sf.net/projects/lksctp
32  *
33  * Written or modified by:
34  *    Randall Stewart	    <randall@sctp.chicago.il.us>
35  *    Ken Morneau	    <kmorneau@cisco.com>
36  *    Qiaobing Xie	    <qxie1@email.mot.com>
37  *    La Monte H.P. Yarroll <piggy@acm.org>
38  *    Karl Knutson	    <karl@athena.chicago.il.us>
39  *    Jon Grimm		    <jgrimm@us.ibm.com>
40  *    Xingang Guo	    <xingang.guo@intel.com>
41  *    Hui Huang		    <hui.huang@nokia.com>
42  *    Sridhar Samudrala	    <sri@us.ibm.com>
43  *    Daisy Chang	    <daisyc@us.ibm.com>
44  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
45  *    Ardelle Fan	    <ardelle.fan@intel.com>
46  *    Ryan Layer	    <rmlayer@us.ibm.com>
47  *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
48  *    Kevin Gao             <kevin.gao@intel.com>
49  *
50  * Any bugs reported given to us we will try to fix... any fixes shared will
51  * be incorporated into the next SCTP release.
52  */
53 
54 #ifndef __sctp_structs_h__
55 #define __sctp_structs_h__
56 
57 #include <linux/time.h>		/* We get struct timespec.    */
58 #include <linux/socket.h>	/* linux/in.h needs this!!    */
59 #include <linux/in.h>		/* We get struct sockaddr_in. */
60 #include <linux/in6.h>		/* We get struct in6_addr     */
61 #include <linux/ipv6.h>
62 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
63 #include <asm/atomic.h>		/* This gets us atomic counters.  */
64 #include <linux/skbuff.h>	/* We need sk_buff_head. */
65 #include <linux/workqueue.h>	/* We need tq_struct.	 */
66 #include <linux/sctp.h>		/* We need sctp* header structs.  */
67 #include <net/sctp/auth.h>	/* We need auth specific structs */
68 
69 /* A convenience structure for handling sockaddr structures.
70  * We should wean ourselves off this.
71  */
72 union sctp_addr {
73 	struct sockaddr_in v4;
74 	struct sockaddr_in6 v6;
75 	struct sockaddr sa;
76 };
77 
78 /* Forward declarations for data structures. */
79 struct sctp_globals;
80 struct sctp_endpoint;
81 struct sctp_association;
82 struct sctp_transport;
83 struct sctp_packet;
84 struct sctp_chunk;
85 struct sctp_inq;
86 struct sctp_outq;
87 struct sctp_bind_addr;
88 struct sctp_ulpq;
89 struct sctp_ep_common;
90 struct sctp_ssnmap;
91 struct crypto_hash;
92 
93 
94 #include <net/sctp/tsnmap.h>
95 #include <net/sctp/ulpevent.h>
96 #include <net/sctp/ulpqueue.h>
97 
98 /* Structures useful for managing bind/connect. */
99 
100 struct sctp_bind_bucket {
101 	unsigned short	port;
102 	unsigned short	fastreuse;
103 	struct hlist_node	node;
104 	struct hlist_head	owner;
105 };
106 
107 struct sctp_bind_hashbucket {
108 	spinlock_t	lock;
109 	struct hlist_head	chain;
110 };
111 
112 /* Used for hashing all associations.  */
113 struct sctp_hashbucket {
114 	rwlock_t	lock;
115 	struct hlist_head	chain;
116 } __attribute__((__aligned__(8)));
117 
118 
119 /* The SCTP globals structure. */
120 extern struct sctp_globals {
121 	/* RFC2960 Section 14. Suggested SCTP Protocol Parameter Values
122 	 *
123 	 * The following protocol parameters are RECOMMENDED:
124 	 *
125 	 * RTO.Initial		    - 3	 seconds
126 	 * RTO.Min		    - 1	 second
127 	 * RTO.Max		   -  60 seconds
128 	 * RTO.Alpha		    - 1/8  (3 when converted to right shifts.)
129 	 * RTO.Beta		    - 1/4  (2 when converted to right shifts.)
130 	 */
131 	unsigned int rto_initial;
132 	unsigned int rto_min;
133 	unsigned int rto_max;
134 
135 	/* Note: rto_alpha and rto_beta are really defined as inverse
136 	 * powers of two to facilitate integer operations.
137 	 */
138 	int rto_alpha;
139 	int rto_beta;
140 
141 	/* Max.Burst		    - 4 */
142 	int max_burst;
143 
144 	/* Whether Cookie Preservative is enabled(1) or not(0) */
145 	int cookie_preserve_enable;
146 
147 	/* Valid.Cookie.Life	    - 60  seconds  */
148 	unsigned int valid_cookie_life;
149 
150 	/* Delayed SACK timeout  200ms default*/
151 	unsigned int sack_timeout;
152 
153 	/* HB.interval		    - 30 seconds  */
154 	unsigned int hb_interval;
155 
156 	/* Association.Max.Retrans  - 10 attempts
157 	 * Path.Max.Retrans	    - 5	 attempts (per destination address)
158 	 * Max.Init.Retransmits	    - 8	 attempts
159 	 */
160 	int max_retrans_association;
161 	int max_retrans_path;
162 	int max_retrans_init;
163 
164 	/*
165 	 * Policy for preforming sctp/socket accounting
166 	 * 0   - do socket level accounting, all assocs share sk_sndbuf
167 	 * 1   - do sctp accounting, each asoc may use sk_sndbuf bytes
168 	 */
169 	int sndbuf_policy;
170 
171 	/*
172 	 * Policy for preforming sctp/socket accounting
173 	 * 0   - do socket level accounting, all assocs share sk_rcvbuf
174 	 * 1   - do sctp accounting, each asoc may use sk_rcvbuf bytes
175 	 */
176 	int rcvbuf_policy;
177 
178 	/* The following variables are implementation specific.	 */
179 
180 	/* Default initialization values to be applied to new associations. */
181 	__u16 max_instreams;
182 	__u16 max_outstreams;
183 
184 	/* This is a list of groups of functions for each address
185 	 * family that we support.
186 	 */
187 	struct list_head address_families;
188 
189 	/* This is the hash of all endpoints. */
190 	int ep_hashsize;
191 	struct sctp_hashbucket *ep_hashtable;
192 
193 	/* This is the hash of all associations. */
194 	int assoc_hashsize;
195 	struct sctp_hashbucket *assoc_hashtable;
196 
197 	/* This is the sctp port control hash.	*/
198 	int port_hashsize;
199 	struct sctp_bind_hashbucket *port_hashtable;
200 
201 	/* This is the global local address list.
202 	 * We actively maintain this complete list of addresses on
203 	 * the system by catching address add/delete events.
204 	 *
205 	 * It is a list of sctp_sockaddr_entry.
206 	 */
207 	struct list_head local_addr_list;
208 
209 	/* Lock that protects the local_addr_list writers */
210 	spinlock_t addr_list_lock;
211 
212 	/* Flag to indicate if addip is enabled. */
213 	int addip_enable;
214 	int addip_noauth_enable;
215 
216 	/* Flag to indicate if PR-SCTP is enabled. */
217 	int prsctp_enable;
218 
219 	/* Flag to idicate if SCTP-AUTH is enabled */
220 	int auth_enable;
221 
222 	/* Flag to indicate whether computing and verifying checksum
223 	 * is disabled. */
224         int checksum_disable;
225 } sctp_globals;
226 
227 #define sctp_rto_initial		(sctp_globals.rto_initial)
228 #define sctp_rto_min			(sctp_globals.rto_min)
229 #define sctp_rto_max			(sctp_globals.rto_max)
230 #define sctp_rto_alpha			(sctp_globals.rto_alpha)
231 #define sctp_rto_beta			(sctp_globals.rto_beta)
232 #define sctp_max_burst			(sctp_globals.max_burst)
233 #define sctp_valid_cookie_life		(sctp_globals.valid_cookie_life)
234 #define sctp_cookie_preserve_enable	(sctp_globals.cookie_preserve_enable)
235 #define sctp_max_retrans_association	(sctp_globals.max_retrans_association)
236 #define sctp_sndbuf_policy	 	(sctp_globals.sndbuf_policy)
237 #define sctp_rcvbuf_policy	 	(sctp_globals.rcvbuf_policy)
238 #define sctp_max_retrans_path		(sctp_globals.max_retrans_path)
239 #define sctp_max_retrans_init		(sctp_globals.max_retrans_init)
240 #define sctp_sack_timeout		(sctp_globals.sack_timeout)
241 #define sctp_hb_interval		(sctp_globals.hb_interval)
242 #define sctp_max_instreams		(sctp_globals.max_instreams)
243 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
244 #define sctp_address_families		(sctp_globals.address_families)
245 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
246 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
247 #define sctp_assoc_hashsize		(sctp_globals.assoc_hashsize)
248 #define sctp_assoc_hashtable		(sctp_globals.assoc_hashtable)
249 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
250 #define sctp_port_rover			(sctp_globals.port_rover)
251 #define sctp_port_alloc_lock		(sctp_globals.port_alloc_lock)
252 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
253 #define sctp_local_addr_list		(sctp_globals.local_addr_list)
254 #define sctp_local_addr_lock		(sctp_globals.addr_list_lock)
255 #define sctp_addip_enable		(sctp_globals.addip_enable)
256 #define sctp_addip_noauth		(sctp_globals.addip_noauth_enable)
257 #define sctp_prsctp_enable		(sctp_globals.prsctp_enable)
258 #define sctp_auth_enable		(sctp_globals.auth_enable)
259 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
260 
261 /* SCTP Socket type: UDP or TCP style. */
262 typedef enum {
263 	SCTP_SOCKET_UDP = 0,
264 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
265 	SCTP_SOCKET_TCP
266 } sctp_socket_type_t;
267 
268 /* Per socket SCTP information. */
269 struct sctp_sock {
270 	/* inet_sock has to be the first member of sctp_sock */
271 	struct inet_sock inet;
272 	/* What kind of a socket is this? */
273 	sctp_socket_type_t type;
274 
275 	/* PF_ family specific functions.  */
276 	struct sctp_pf *pf;
277 
278 	/* Access to HMAC transform. */
279 	struct crypto_hash *hmac;
280 
281 	/* What is our base endpointer? */
282 	struct sctp_endpoint *ep;
283 
284 	struct sctp_bind_bucket *bind_hash;
285 	/* Various Socket Options.  */
286 	__u16 default_stream;
287 	__u32 default_ppid;
288 	__u16 default_flags;
289 	__u32 default_context;
290 	__u32 default_timetolive;
291 	__u32 default_rcv_context;
292 	int max_burst;
293 
294 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
295 	 * the destination address every heartbeat interval. This value
296 	 * will be inherited by all new associations.
297 	 */
298 	__u32 hbinterval;
299 
300 	/* This is the max_retrans value for new associations. */
301 	__u16 pathmaxrxt;
302 
303 	/* The initial Path MTU to use for new associations. */
304 	__u32 pathmtu;
305 
306 	/* The default SACK delay timeout for new associations. */
307 	__u32 sackdelay;
308 	__u32 sackfreq;
309 
310 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
311 	__u32 param_flags;
312 
313 	struct sctp_initmsg initmsg;
314 	struct sctp_rtoinfo rtoinfo;
315 	struct sctp_paddrparams paddrparam;
316 	struct sctp_event_subscribe subscribe;
317 	struct sctp_assocparams assocparams;
318 	int user_frag;
319 	__u32 autoclose;
320 	__u8 nodelay;
321 	__u8 disable_fragments;
322 	__u8 v4mapped;
323 	__u8 frag_interleave;
324 	__u32 adaptation_ind;
325 	__u32 pd_point;
326 
327 	atomic_t pd_mode;
328 	/* Receive to here while partial delivery is in effect. */
329 	struct sk_buff_head pd_lobby;
330 };
331 
332 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
333 {
334        return (struct sctp_sock *)sk;
335 }
336 
337 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
338 {
339        return (struct sock *)sp;
340 }
341 
342 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
343 struct sctp6_sock {
344        struct sctp_sock  sctp;
345        struct ipv6_pinfo inet6;
346 };
347 #endif /* CONFIG_IPV6 */
348 
349 
350 /* This is our APPLICATION-SPECIFIC state cookie.
351  * THIS IS NOT DICTATED BY THE SPECIFICATION.
352  */
353 /* These are the parts of an association which we send in the cookie.
354  * Most of these are straight out of:
355  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
356  *
357  */
358 
359 struct sctp_cookie {
360 
361 	/* My	       : Tag expected in every inbound packet and sent
362 	 * Verification: in the INIT or INIT ACK chunk.
363 	 * Tag	       :
364 	 */
365 	__u32 my_vtag;
366 
367 	/* Peer's      : Tag expected in every outbound packet except
368 	 * Verification: in the INIT chunk.
369 	 * Tag	       :
370 	 */
371 	__u32 peer_vtag;
372 
373 	/* The rest of these are not from the spec, but really need to
374 	 * be in the cookie.
375 	 */
376 
377 	/* My Tie Tag  : Assist in discovering a restarting association. */
378 	__u32 my_ttag;
379 
380 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
381 	__u32 peer_ttag;
382 
383 	/* When does this cookie expire? */
384 	struct timeval expiration;
385 
386 	/* Number of inbound/outbound streams which are set
387 	 * and negotiated during the INIT process.
388 	 */
389 	__u16 sinit_num_ostreams;
390 	__u16 sinit_max_instreams;
391 
392 	/* This is the first sequence number I used.  */
393 	__u32 initial_tsn;
394 
395 	/* This holds the originating address of the INIT packet.  */
396 	union sctp_addr peer_addr;
397 
398 	/* IG Section 2.35.3
399 	 * Include the source port of the INIT-ACK
400 	 */
401 	__u16		my_port;
402 
403 	__u8 prsctp_capable;
404 
405 	/* Padding for future use */
406 	__u8 padding;
407 
408 	__u32 adaptation_ind;
409 
410 	__u8 auth_random[sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH];
411 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS + 2];
412 	__u8 auth_chunks[sizeof(sctp_paramhdr_t) + SCTP_AUTH_MAX_CHUNKS];
413 
414 	/* This is a shim for my peer's INIT packet, followed by
415 	 * a copy of the raw address list of the association.
416 	 * The length of the raw address list is saved in the
417 	 * raw_addr_list_len field, which will be used at the time when
418 	 * the association TCB is re-constructed from the cookie.
419 	 */
420 	__u32 raw_addr_list_len;
421 	struct sctp_init_chunk peer_init[0];
422 };
423 
424 
425 /* The format of our cookie that we send to our peer. */
426 struct sctp_signed_cookie {
427 	__u8 signature[SCTP_SECRET_SIZE];
428 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
429 	struct sctp_cookie c;
430 } __attribute__((packed));
431 
432 /* This is another convenience type to allocate memory for address
433  * params for the maximum size and pass such structures around
434  * internally.
435  */
436 union sctp_addr_param {
437 	struct sctp_paramhdr p;
438 	struct sctp_ipv4addr_param v4;
439 	struct sctp_ipv6addr_param v6;
440 };
441 
442 /* A convenience type to allow walking through the various
443  * parameters and avoid casting all over the place.
444  */
445 union sctp_params {
446 	void *v;
447 	struct sctp_paramhdr *p;
448 	struct sctp_cookie_preserve_param *life;
449 	struct sctp_hostname_param *dns;
450 	struct sctp_cookie_param *cookie;
451 	struct sctp_supported_addrs_param *sat;
452 	struct sctp_ipv4addr_param *v4;
453 	struct sctp_ipv6addr_param *v6;
454 	union sctp_addr_param *addr;
455 	struct sctp_adaptation_ind_param *aind;
456 	struct sctp_supported_ext_param *ext;
457 	struct sctp_random_param *random;
458 	struct sctp_chunks_param *chunks;
459 	struct sctp_hmac_algo_param *hmac_algo;
460 	struct sctp_addip_param *addip;
461 };
462 
463 /* RFC 2960.  Section 3.3.5 Heartbeat.
464  *    Heartbeat Information: variable length
465  *    The Sender-specific Heartbeat Info field should normally include
466  *    information about the sender's current time when this HEARTBEAT
467  *    chunk is sent and the destination transport address to which this
468  *    HEARTBEAT is sent (see Section 8.3).
469  */
470 typedef struct sctp_sender_hb_info {
471 	struct sctp_paramhdr param_hdr;
472 	union sctp_addr daddr;
473 	unsigned long sent_at;
474 	__u64 hb_nonce;
475 } __attribute__((packed)) sctp_sender_hb_info_t;
476 
477 /*
478  *  RFC 2960 1.3.2 Sequenced Delivery within Streams
479  *
480  *  The term "stream" is used in SCTP to refer to a sequence of user
481  *  messages that are to be delivered to the upper-layer protocol in
482  *  order with respect to other messages within the same stream.  This is
483  *  in contrast to its usage in TCP, where it refers to a sequence of
484  *  bytes (in this document a byte is assumed to be eight bits).
485  *  ...
486  *
487  *  This is the structure we use to track both our outbound and inbound
488  *  SSN, or Stream Sequence Numbers.
489  */
490 
491 struct sctp_stream {
492 	__u16 *ssn;
493 	unsigned int len;
494 };
495 
496 struct sctp_ssnmap {
497 	struct sctp_stream in;
498 	struct sctp_stream out;
499 	int malloced;
500 };
501 
502 struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
503 				    gfp_t gfp);
504 void sctp_ssnmap_free(struct sctp_ssnmap *map);
505 void sctp_ssnmap_clear(struct sctp_ssnmap *map);
506 
507 /* What is the current SSN number for this stream? */
508 static inline __u16 sctp_ssn_peek(struct sctp_stream *stream, __u16 id)
509 {
510 	return stream->ssn[id];
511 }
512 
513 /* Return the next SSN number for this stream.	*/
514 static inline __u16 sctp_ssn_next(struct sctp_stream *stream, __u16 id)
515 {
516 	return stream->ssn[id]++;
517 }
518 
519 /* Skip over this ssn and all below. */
520 static inline void sctp_ssn_skip(struct sctp_stream *stream, __u16 id,
521 				 __u16 ssn)
522 {
523 	stream->ssn[id] = ssn+1;
524 }
525 
526 /*
527  * Pointers to address related SCTP functions.
528  * (i.e. things that depend on the address family.)
529  */
530 struct sctp_af {
531 	int		(*sctp_xmit)	(struct sk_buff *skb,
532 					 struct sctp_transport *);
533 	int		(*setsockopt)	(struct sock *sk,
534 					 int level,
535 					 int optname,
536 					 char __user *optval,
537 					 int optlen);
538 	int		(*getsockopt)	(struct sock *sk,
539 					 int level,
540 					 int optname,
541 					 char __user *optval,
542 					 int __user *optlen);
543 	int		(*compat_setsockopt)	(struct sock *sk,
544 					 int level,
545 					 int optname,
546 					 char __user *optval,
547 					 int optlen);
548 	int		(*compat_getsockopt)	(struct sock *sk,
549 					 int level,
550 					 int optname,
551 					 char __user *optval,
552 					 int __user *optlen);
553 	struct dst_entry *(*get_dst)	(struct sctp_association *asoc,
554 					 union sctp_addr *daddr,
555 					 union sctp_addr *saddr);
556 	void		(*get_saddr)	(struct sctp_sock *sk,
557 					 struct sctp_association *asoc,
558 					 struct dst_entry *dst,
559 					 union sctp_addr *daddr,
560 					 union sctp_addr *saddr);
561 	void		(*copy_addrlist) (struct list_head *,
562 					  struct net_device *);
563 	void		(*dst_saddr)	(union sctp_addr *saddr,
564 					 struct dst_entry *dst,
565 					 __be16 port);
566 	int		(*cmp_addr)	(const union sctp_addr *addr1,
567 					 const union sctp_addr *addr2);
568 	void		(*addr_copy)	(union sctp_addr *dst,
569 					 union sctp_addr *src);
570 	void		(*from_skb)	(union sctp_addr *,
571 					 struct sk_buff *skb,
572 					 int saddr);
573 	void		(*from_sk)	(union sctp_addr *,
574 					 struct sock *sk);
575 	void		(*to_sk_saddr)	(union sctp_addr *,
576 					 struct sock *sk);
577 	void		(*to_sk_daddr)	(union sctp_addr *,
578 					 struct sock *sk);
579 	void		(*from_addr_param) (union sctp_addr *,
580 					    union sctp_addr_param *,
581 					    __be16 port, int iif);
582 	int		(*to_addr_param) (const union sctp_addr *,
583 					  union sctp_addr_param *);
584 	int		(*addr_valid)	(union sctp_addr *,
585 					 struct sctp_sock *,
586 					 const struct sk_buff *);
587 	sctp_scope_t	(*scope) (union sctp_addr *);
588 	void		(*inaddr_any)	(union sctp_addr *, __be16);
589 	int		(*is_any)	(const union sctp_addr *);
590 	int		(*available)	(union sctp_addr *,
591 					 struct sctp_sock *);
592 	int		(*skb_iif)	(const struct sk_buff *sk);
593 	int		(*is_ce)	(const struct sk_buff *sk);
594 	void		(*seq_dump_addr)(struct seq_file *seq,
595 					 union sctp_addr *addr);
596 	void		(*ecn_capable)(struct sock *sk);
597 	__u16		net_header_len;
598 	int		sockaddr_len;
599 	sa_family_t	sa_family;
600 	struct list_head list;
601 };
602 
603 struct sctp_af *sctp_get_af_specific(sa_family_t);
604 int sctp_register_af(struct sctp_af *);
605 
606 /* Protocol family functions. */
607 struct sctp_pf {
608 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
609 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
610 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
611 	int  (*cmp_addr) (const union sctp_addr *,
612 			  const union sctp_addr *,
613 			  struct sctp_sock *);
614 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
615 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
616 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
617 	struct sock *(*create_accept_sk) (struct sock *sk,
618 					  struct sctp_association *asoc);
619 	void (*addr_v4map) (struct sctp_sock *, union sctp_addr *);
620 	struct sctp_af *af;
621 };
622 
623 
624 /* Structure to track chunk fragments that have been acked, but peer
625  * fragments of the same message have not.
626  */
627 struct sctp_datamsg {
628 	/* Chunks waiting to be submitted to lower layer. */
629 	struct list_head chunks;
630 	/* Chunks that have been transmitted. */
631 	struct list_head track;
632 	/* Reference counting. */
633 	atomic_t refcnt;
634 	/* When is this message no longer interesting to the peer? */
635 	unsigned long expires_at;
636 	/* Did the messenge fail to send? */
637 	int send_error;
638 	char send_failed;
639 	/* Control whether chunks from this message can be abandoned. */
640 	char can_abandon;
641 };
642 
643 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
644 					    struct sctp_sndrcvinfo *,
645 					    struct msghdr *, int len);
646 void sctp_datamsg_put(struct sctp_datamsg *);
647 void sctp_chunk_fail(struct sctp_chunk *, int error);
648 int sctp_chunk_abandoned(struct sctp_chunk *);
649 
650 /* RFC2960 1.4 Key Terms
651  *
652  * o Chunk: A unit of information within an SCTP packet, consisting of
653  * a chunk header and chunk-specific content.
654  *
655  * As a matter of convenience, we remember the SCTP common header for
656  * each chunk as well as a few other header pointers...
657  */
658 struct sctp_chunk {
659 	struct list_head list;
660 
661 	atomic_t refcnt;
662 
663 	/* This is our link to the per-transport transmitted list.  */
664 	struct list_head transmitted_list;
665 
666 	/* This field is used by chunks that hold fragmented data.
667 	 * For the first fragment this is the list that holds the rest of
668 	 * fragments. For the remaining fragments, this is the link to the
669 	 * frag_list maintained in the first fragment.
670 	 */
671 	struct list_head frag_list;
672 
673 	/* This points to the sk_buff containing the actual data.  */
674 	struct sk_buff *skb;
675 
676 	/* These are the SCTP headers by reverse order in a packet.
677 	 * Note that some of these may happen more than once.  In that
678 	 * case, we point at the "current" one, whatever that means
679 	 * for that level of header.
680 	 */
681 
682 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
683 	union sctp_params param_hdr;
684 	union {
685 		__u8 *v;
686 		struct sctp_datahdr *data_hdr;
687 		struct sctp_inithdr *init_hdr;
688 		struct sctp_sackhdr *sack_hdr;
689 		struct sctp_heartbeathdr *hb_hdr;
690 		struct sctp_sender_hb_info *hbs_hdr;
691 		struct sctp_shutdownhdr *shutdown_hdr;
692 		struct sctp_signed_cookie *cookie_hdr;
693 		struct sctp_ecnehdr *ecne_hdr;
694 		struct sctp_cwrhdr *ecn_cwr_hdr;
695 		struct sctp_errhdr *err_hdr;
696 		struct sctp_addiphdr *addip_hdr;
697 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
698 		struct sctp_authhdr *auth_hdr;
699 	} subh;
700 
701 	__u8 *chunk_end;
702 
703 	struct sctp_chunkhdr *chunk_hdr;
704 	struct sctphdr *sctp_hdr;
705 
706 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
707 	struct sctp_sndrcvinfo sinfo;
708 
709 	/* Which association does this belong to?  */
710 	struct sctp_association *asoc;
711 
712 	/* What endpoint received this chunk? */
713 	struct sctp_ep_common *rcvr;
714 
715 	/* We fill this in if we are calculating RTT. */
716 	unsigned long sent_at;
717 
718 	/* What is the origin IP address for this chunk?  */
719 	union sctp_addr source;
720 	/* Destination address for this chunk. */
721 	union sctp_addr dest;
722 
723 	/* For outbound message, track all fragments for SEND_FAILED. */
724 	struct sctp_datamsg *msg;
725 
726 	/* For an inbound chunk, this tells us where it came from.
727 	 * For an outbound chunk, it tells us where we'd like it to
728 	 * go.	It is NULL if we have no preference.
729 	 */
730 	struct sctp_transport *transport;
731 
732 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
733 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
734 	 * spec violates the principle premis that all chunks are processed
735 	 * in order.
736 	 */
737 	struct sk_buff *auth_chunk;
738 
739 #define SCTP_CAN_FRTX 0x0
740 #define SCTP_NEED_FRTX 0x1
741 #define SCTP_DONT_FRTX 0x2
742 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
743 		resent:1,		/* Has this chunk ever been resent. */
744 		has_tsn:1,		/* Does this chunk have a TSN yet? */
745 		has_ssn:1,		/* Does this chunk have a SSN yet? */
746 		singleton:1,		/* Only chunk in the packet? */
747 		end_of_packet:1,	/* Last chunk in the packet? */
748 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
749 		pdiscard:1,		/* Discard the whole packet now? */
750 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
751 		data_accepted:1,	/* At least 1 chunk accepted */
752 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
753 		has_asconf:1,		/* IN: have seen an asconf before */
754 		tsn_missing_report:2,	/* Data chunk missing counter. */
755 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
756 };
757 
758 void sctp_chunk_hold(struct sctp_chunk *);
759 void sctp_chunk_put(struct sctp_chunk *);
760 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
761 			  struct iovec *data);
762 void sctp_chunk_free(struct sctp_chunk *);
763 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
764 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
765 				 const struct sctp_association *,
766 				 struct sock *);
767 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
768 		     union sctp_addr *);
769 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
770 
771 enum {
772 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
773 	SCTP_ADDR_SRC,		/* address can be used as source */
774 	SCTP_ADDR_DEL,		/* address about to be deleted */
775 };
776 
777 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
778 struct sctp_sockaddr_entry {
779 	struct list_head list;
780 	struct rcu_head	rcu;
781 	union sctp_addr a;
782 	__u8 state;
783 	__u8 valid;
784 };
785 
786 typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);
787 
788 /* This structure holds lists of chunks as we are assembling for
789  * transmission.
790  */
791 struct sctp_packet {
792 	/* These are the SCTP header values (host order) for the packet. */
793 	__u16 source_port;
794 	__u16 destination_port;
795 	__u32 vtag;
796 
797 	/* This contains the payload chunks.  */
798 	struct list_head chunk_list;
799 
800 	/* This is the overhead of the sctp and ip headers. */
801 	size_t overhead;
802 	/* This is the total size of all chunks INCLUDING padding.  */
803 	size_t size;
804 
805 	/* The packet is destined for this transport address.
806 	 * The function we finally use to pass down to the next lower
807 	 * layer lives in the transport structure.
808 	 */
809 	struct sctp_transport *transport;
810 
811 	/* pointer to the auth chunk for this packet */
812 	struct sctp_chunk *auth;
813 
814 	/* This packet contains a COOKIE-ECHO chunk. */
815 	__u8 has_cookie_echo;
816 
817 	/* This packet contains a SACK chunk. */
818 	__u8 has_sack;
819 
820 	/* This packet contains an AUTH chunk */
821 	__u8 has_auth;
822 
823 	/* This packet contains at least 1 DATA chunk */
824 	__u8 has_data;
825 
826 	/* SCTP cannot fragment this packet. So let ip fragment it. */
827 	__u8 ipfragok;
828 
829 	__u8 malloced;
830 };
831 
832 struct sctp_packet *sctp_packet_init(struct sctp_packet *,
833 				     struct sctp_transport *,
834 				     __u16 sport, __u16 dport);
835 struct sctp_packet *sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
836 sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *,
837                                        struct sctp_chunk *, int);
838 sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *,
839                                      struct sctp_chunk *);
840 int sctp_packet_transmit(struct sctp_packet *);
841 void sctp_packet_free(struct sctp_packet *);
842 
843 static inline int sctp_packet_empty(struct sctp_packet *packet)
844 {
845 	return (packet->size == packet->overhead);
846 }
847 
848 /* This represents a remote transport address.
849  * For local transport addresses, we just use union sctp_addr.
850  *
851  * RFC2960 Section 1.4 Key Terms
852  *
853  *   o	Transport address:  A Transport Address is traditionally defined
854  *	by Network Layer address, Transport Layer protocol and Transport
855  *	Layer port number.  In the case of SCTP running over IP, a
856  *	transport address is defined by the combination of an IP address
857  *	and an SCTP port number (where SCTP is the Transport protocol).
858  *
859  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
860  *
861  *   o	The sender keeps a separate congestion control parameter set for
862  *	each of the destination addresses it can send to (not each
863  *	source-destination pair but for each destination).  The parameters
864  *	should decay if the address is not used for a long enough time
865  *	period.
866  *
867  */
868 struct sctp_transport {
869 	/* A list of transports. */
870 	struct list_head transports;
871 
872 	/* Reference counting. */
873 	atomic_t refcnt;
874 	int	 dead;
875 
876 	/* This is the peer's IP address and port. */
877 	union sctp_addr ipaddr;
878 
879 	/* These are the functions we call to handle LLP stuff.	 */
880 	struct sctp_af *af_specific;
881 
882 	/* Which association do we belong to?  */
883 	struct sctp_association *asoc;
884 
885 	/* RFC2960
886 	 *
887 	 * 12.3 Per Transport Address Data
888 	 *
889 	 * For each destination transport address in the peer's
890 	 * address list derived from the INIT or INIT ACK chunk, a
891 	 * number of data elements needs to be maintained including:
892 	 */
893 	/* RTO	       : The current retransmission timeout value.  */
894 	unsigned long rto;
895 	unsigned long last_rto;
896 
897 	__u32 rtt;		/* This is the most recent RTT.	 */
898 
899 	/* RTTVAR      : The current RTT variation.  */
900 	__u32 rttvar;
901 
902 	/* SRTT	       : The current smoothed round trip time.	*/
903 	__u32 srtt;
904 
905 	/* RTO-Pending : A flag used to track if one of the DATA
906 	 *		chunks sent to this address is currently being
907 	 *		used to compute a RTT. If this flag is 0,
908 	 *		the next DATA chunk sent to this destination
909 	 *		should be used to compute a RTT and this flag
910 	 *		should be set. Every time the RTT
911 	 *		calculation completes (i.e. the DATA chunk
912 	 *		is SACK'd) clear this flag.
913 	 * hb_sent : a flag that signals that we have a pending heartbeat.
914 	 */
915 	__u8 rto_pending;
916 	__u8 hb_sent;
917 
918 	/* Flag to track the current fast recovery state */
919 	__u8 fast_recovery;
920 
921 	/*
922 	 * These are the congestion stats.
923 	 */
924 	/* cwnd	       : The current congestion window.	 */
925 	__u32 cwnd;		  /* This is the actual cwnd.  */
926 
927 	/* ssthresh    : The current slow start threshold value.  */
928 	__u32 ssthresh;
929 
930 	/* partial     : The tracking method for increase of cwnd when in
931 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
932 	 */
933 	__u32 partial_bytes_acked;
934 
935 	/* Data that has been sent, but not acknowledged. */
936 	__u32 flight_size;
937 
938 	/* TSN marking the fast recovery exit point */
939 	__u32 fast_recovery_exit;
940 
941 	/* Destination */
942 	struct dst_entry *dst;
943 	/* Source address. */
944 	union sctp_addr saddr;
945 
946 	/* When was the last time(in jiffies) that a data packet was sent on
947 	 * this transport?  This is used to adjust the cwnd when the transport
948 	 * becomes inactive.
949 	 */
950 	unsigned long last_time_used;
951 
952 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
953 	 * the destination address every heartbeat interval.
954 	 */
955 	unsigned long hbinterval;
956 
957 	/* SACK delay timeout */
958 	unsigned long sackdelay;
959 	__u32 sackfreq;
960 
961 	/* When was the last time (in jiffies) that we heard from this
962 	 * transport?  We use this to pick new active and retran paths.
963 	 */
964 	unsigned long last_time_heard;
965 
966 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
967 	 * indication based on ECNE chunk.
968 	 */
969 	unsigned long last_time_ecne_reduced;
970 
971 	/* This is the max_retrans value for the transport and will
972 	 * be initialized from the assocs value.  This can be changed
973 	 * using SCTP_SET_PEER_ADDR_PARAMS socket option.
974 	 */
975 	__u16 pathmaxrxt;
976 
977 	/* is the Path MTU update pending on this tranport */
978 	__u8 pmtu_pending;
979 
980 	/* PMTU	      : The current known path MTU.  */
981 	__u32 pathmtu;
982 
983 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
984 	__u32 param_flags;
985 
986 	/* The number of times INIT has been sent on this transport. */
987 	int init_sent_count;
988 
989 	/* state       : The current state of this destination,
990 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKOWN.
991 	 */
992 	int state;
993 
994 	/* These are the error stats for this destination.  */
995 
996 	/* Error count : The current error count for this destination.	*/
997 	unsigned short error_count;
998 
999 	/* Per	       : A timer used by each destination.
1000 	 * Destination :
1001 	 * Timer       :
1002 	 *
1003 	 * [Everywhere else in the text this is called T3-rtx. -ed]
1004 	 */
1005 	struct timer_list T3_rtx_timer;
1006 
1007 	/* Heartbeat timer is per destination. */
1008 	struct timer_list hb_timer;
1009 
1010 	/* Since we're using per-destination retransmission timers
1011 	 * (see above), we're also using per-destination "transmitted"
1012 	 * queues.  This probably ought to be a private struct
1013 	 * accessible only within the outqueue, but it's not, yet.
1014 	 */
1015 	struct list_head transmitted;
1016 
1017 	/* We build bundle-able packets for this transport here.  */
1018 	struct sctp_packet packet;
1019 
1020 	/* This is the list of transports that have chunks to send.  */
1021 	struct list_head send_ready;
1022 
1023 	int malloced; /* Is this structure kfree()able? */
1024 
1025 	/* State information saved for SFR_CACC algorithm. The key
1026 	 * idea in SFR_CACC is to maintain state at the sender on a
1027 	 * per-destination basis when a changeover happens.
1028 	 *	char changeover_active;
1029 	 *	char cycling_changeover;
1030 	 *	__u32 next_tsn_at_change;
1031 	 *	char cacc_saw_newack;
1032 	 */
1033 	struct {
1034 		/* An unsigned integer, which stores the next TSN to be
1035 		 * used by the sender, at the moment of changeover.
1036 		 */
1037 		__u32 next_tsn_at_change;
1038 
1039 		/* A flag which indicates the occurrence of a changeover */
1040 		char changeover_active;
1041 
1042 		/* A flag which indicates whether the change of primary is
1043 		 * the first switch to this destination address during an
1044 		 * active switch.
1045 		 */
1046 		char cycling_changeover;
1047 
1048 		/* A temporary flag, which is used during the processing of
1049 		 * a SACK to estimate the causative TSN(s)'s group.
1050 		 */
1051 		char cacc_saw_newack;
1052 	} cacc;
1053 
1054 	/* 64-bit random number sent with heartbeat. */
1055 	__u64 hb_nonce;
1056 };
1057 
1058 struct sctp_transport *sctp_transport_new(const union sctp_addr *,
1059 					  gfp_t);
1060 void sctp_transport_set_owner(struct sctp_transport *,
1061 			      struct sctp_association *);
1062 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1063 			  struct sctp_sock *);
1064 void sctp_transport_pmtu(struct sctp_transport *);
1065 void sctp_transport_free(struct sctp_transport *);
1066 void sctp_transport_reset_timers(struct sctp_transport *, int);
1067 void sctp_transport_hold(struct sctp_transport *);
1068 void sctp_transport_put(struct sctp_transport *);
1069 void sctp_transport_update_rto(struct sctp_transport *, __u32);
1070 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1071 void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
1072 unsigned long sctp_transport_timeout(struct sctp_transport *);
1073 void sctp_transport_reset(struct sctp_transport *);
1074 void sctp_transport_update_pmtu(struct sctp_transport *, u32);
1075 
1076 
1077 /* This is the structure we use to queue packets as they come into
1078  * SCTP.  We write packets to it and read chunks from it.
1079  */
1080 struct sctp_inq {
1081 	/* This is actually a queue of sctp_chunk each
1082 	 * containing a partially decoded packet.
1083 	 */
1084 	struct list_head in_chunk_list;
1085 	/* This is the packet which is currently off the in queue and is
1086 	 * being worked on through the inbound chunk processing.
1087 	 */
1088 	struct sctp_chunk *in_progress;
1089 
1090 	/* This is the delayed task to finish delivering inbound
1091 	 * messages.
1092 	 */
1093 	struct work_struct immediate;
1094 
1095 	int malloced;	     /* Is this structure kfree()able?	*/
1096 };
1097 
1098 void sctp_inq_init(struct sctp_inq *);
1099 void sctp_inq_free(struct sctp_inq *);
1100 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1101 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1102 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1103 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1104 
1105 /* This is the structure we use to hold outbound chunks.  You push
1106  * chunks in and they automatically pop out the other end as bundled
1107  * packets (it calls (*output_handler)()).
1108  *
1109  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1110  * and 8.2 of the v13 draft.
1111  *
1112  * It handles retransmissions.	The connection to the timeout portion
1113  * of the state machine is through sctp_..._timeout() and timeout_handler.
1114  *
1115  * If you feed it SACKs, it will eat them.
1116  *
1117  * If you give it big chunks, it will fragment them.
1118  *
1119  * It assigns TSN's to data chunks.  This happens at the last possible
1120  * instant before transmission.
1121  *
1122  * When free()'d, it empties itself out via output_handler().
1123  */
1124 struct sctp_outq {
1125 	struct sctp_association *asoc;
1126 
1127 	/* Data pending that has never been transmitted.  */
1128 	struct list_head out_chunk_list;
1129 
1130 	unsigned out_qlen;	/* Total length of queued data chunks. */
1131 
1132 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1133 	unsigned error;
1134 
1135 	/* These are control chunks we want to send.  */
1136 	struct list_head control_chunk_list;
1137 
1138 	/* These are chunks that have been sacked but are above the
1139 	 * CTSN, or cumulative tsn ack point.
1140 	 */
1141 	struct list_head sacked;
1142 
1143 	/* Put chunks on this list to schedule them for
1144 	 * retransmission.
1145 	 */
1146 	struct list_head retransmit;
1147 
1148 	/* Put chunks on this list to save them for FWD TSN processing as
1149 	 * they were abandoned.
1150 	 */
1151 	struct list_head abandoned;
1152 
1153 	/* How many unackd bytes do we have in-flight?	*/
1154 	__u32 outstanding_bytes;
1155 
1156 	/* Are we doing fast-rtx on this queue */
1157 	char fast_rtx;
1158 
1159 	/* Corked? */
1160 	char cork;
1161 
1162 	/* Is this structure empty?  */
1163 	char empty;
1164 
1165 	/* Are we kfree()able? */
1166 	char malloced;
1167 };
1168 
1169 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1170 void sctp_outq_teardown(struct sctp_outq *);
1171 void sctp_outq_free(struct sctp_outq*);
1172 int sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk);
1173 int sctp_outq_sack(struct sctp_outq *, struct sctp_sackhdr *);
1174 int sctp_outq_is_empty(const struct sctp_outq *);
1175 void sctp_outq_restart(struct sctp_outq *);
1176 
1177 void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
1178 		     sctp_retransmit_reason_t);
1179 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1180 int sctp_outq_uncork(struct sctp_outq *);
1181 /* Uncork and flush an outqueue.  */
1182 static inline void sctp_outq_cork(struct sctp_outq *q)
1183 {
1184 	q->cork = 1;
1185 }
1186 
1187 /* These bind address data fields common between endpoints and associations */
1188 struct sctp_bind_addr {
1189 
1190 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1191 	 *
1192 	 * SCTP Port:	The local SCTP port number the endpoint is
1193 	 *		bound to.
1194 	 */
1195 	__u16 port;
1196 
1197 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1198 	 *
1199 	 * Address List: The list of IP addresses that this instance
1200 	 *	has bound.  This information is passed to one's
1201 	 *	peer(s) in INIT and INIT ACK chunks.
1202 	 */
1203 	struct list_head address_list;
1204 
1205 	int malloced;	     /* Are we kfree()able?  */
1206 };
1207 
1208 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1209 void sctp_bind_addr_free(struct sctp_bind_addr *);
1210 int sctp_bind_addr_copy(struct sctp_bind_addr *dest,
1211 			const struct sctp_bind_addr *src,
1212 			sctp_scope_t scope, gfp_t gfp,
1213 			int flags);
1214 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1215 			const struct sctp_bind_addr *src,
1216 			gfp_t gfp);
1217 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1218 		       __u8 addr_state, gfp_t gfp);
1219 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1220 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1221 			 struct sctp_sock *);
1222 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1223 			 struct sctp_sock *, struct sctp_sock *);
1224 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1225 			 const union sctp_addr *addr);
1226 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1227 					const union sctp_addr	*addrs,
1228 					int			addrcnt,
1229 					struct sctp_sock	*opt);
1230 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1231 					 int *addrs_len,
1232 					 gfp_t gfp);
1233 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1234 			   __u16 port, gfp_t gfp);
1235 
1236 sctp_scope_t sctp_scope(const union sctp_addr *);
1237 int sctp_in_scope(const union sctp_addr *addr, const sctp_scope_t scope);
1238 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1239 int sctp_addr_is_valid(const union sctp_addr *addr);
1240 
1241 
1242 /* What type of endpoint?  */
1243 typedef enum {
1244 	SCTP_EP_TYPE_SOCKET,
1245 	SCTP_EP_TYPE_ASSOCIATION,
1246 } sctp_endpoint_type_t;
1247 
1248 /*
1249  * A common base class to bridge the implmentation view of a
1250  * socket (usually listening) endpoint versus an association's
1251  * local endpoint.
1252  * This common structure is useful for several purposes:
1253  *   1) Common interface for lookup routines.
1254  *	a) Subfunctions work for either endpoint or association
1255  *	b) Single interface to lookup allows hiding the lookup lock rather
1256  *	   than acquiring it externally.
1257  *   2) Common interface for the inbound chunk handling/state machine.
1258  *   3) Common object handling routines for reference counting, etc.
1259  *   4) Disentangle association lookup from endpoint lookup, where we
1260  *	do not have to find our endpoint to find our association.
1261  *
1262  */
1263 
1264 struct sctp_ep_common {
1265 	/* Fields to help us manage our entries in the hash tables. */
1266 	struct hlist_node node;
1267 	int hashent;
1268 
1269 	/* Runtime type information.  What kind of endpoint is this? */
1270 	sctp_endpoint_type_t type;
1271 
1272 	/* Some fields to help us manage this object.
1273 	 *   refcnt   - Reference count access to this object.
1274 	 *   dead     - Do not attempt to use this object.
1275 	 *   malloced - Do we need to kfree this object?
1276 	 */
1277 	atomic_t    refcnt;
1278 	char	    dead;
1279 	char	    malloced;
1280 
1281 	/* What socket does this endpoint belong to?  */
1282 	struct sock *sk;
1283 
1284 	/* This is where we receive inbound chunks.  */
1285 	struct sctp_inq	  inqueue;
1286 
1287 	/* This substructure includes the defining parameters of the
1288 	 * endpoint:
1289 	 * bind_addr.port is our shared port number.
1290 	 * bind_addr.address_list is our set of local IP addresses.
1291 	 */
1292 	struct sctp_bind_addr bind_addr;
1293 };
1294 
1295 
1296 /* RFC Section 1.4 Key Terms
1297  *
1298  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1299  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1300  *   combination of a set of eligible destination transport addresses to
1301  *   which SCTP packets can be sent and a set of eligible source
1302  *   transport addresses from which SCTP packets can be received.
1303  *   All transport addresses used by an SCTP endpoint must use the
1304  *   same port number, but can use multiple IP addresses. A transport
1305  *   address used by an SCTP endpoint must not be used by another
1306  *   SCTP endpoint. In other words, a transport address is unique
1307  *   to an SCTP endpoint.
1308  *
1309  * From an implementation perspective, each socket has one of these.
1310  * A TCP-style socket will have exactly one association on one of
1311  * these.  An UDP-style socket will have multiple associations hanging
1312  * off one of these.
1313  */
1314 
1315 struct sctp_endpoint {
1316 	/* Common substructure for endpoint and association. */
1317 	struct sctp_ep_common base;
1318 
1319 	/* Associations: A list of current associations and mappings
1320 	 *	      to the data consumers for each association. This
1321 	 *	      may be in the form of a hash table or other
1322 	 *	      implementation dependent structure. The data
1323 	 *	      consumers may be process identification
1324 	 *	      information such as file descriptors, named pipe
1325 	 *	      pointer, or table pointers dependent on how SCTP
1326 	 *	      is implemented.
1327 	 */
1328 	/* This is really a list of struct sctp_association entries. */
1329 	struct list_head asocs;
1330 
1331 	/* Secret Key: A secret key used by this endpoint to compute
1332 	 *	      the MAC.	This SHOULD be a cryptographic quality
1333 	 *	      random number with a sufficient length.
1334 	 *	      Discussion in [RFC1750] can be helpful in
1335 	 *	      selection of the key.
1336 	 */
1337 	__u8 secret_key[SCTP_HOW_MANY_SECRETS][SCTP_SECRET_SIZE];
1338 	int current_key;
1339 	int last_key;
1340 	int key_changed_at;
1341 
1342  	/* digest:  This is a digest of the sctp cookie.  This field is
1343  	 * 	    only used on the receive path when we try to validate
1344  	 * 	    that the cookie has not been tampered with.  We put
1345  	 * 	    this here so we pre-allocate this once and can re-use
1346  	 * 	    on every receive.
1347  	 */
1348  	__u8 *digest;
1349 
1350 	/* sendbuf acct. policy.	*/
1351 	__u32 sndbuf_policy;
1352 
1353 	/* rcvbuf acct. policy.	*/
1354 	__u32 rcvbuf_policy;
1355 
1356 	/* SCTP AUTH: array of the HMACs that will be allocated
1357 	 * we need this per association so that we don't serialize
1358 	 */
1359 	struct crypto_hash **auth_hmacs;
1360 
1361 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1362 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1363 
1364 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1365 	struct sctp_chunks_param *auth_chunk_list;
1366 
1367 	/* SCTP-AUTH: endpoint shared keys */
1368 	struct list_head endpoint_shared_keys;
1369 	__u16 active_key_id;
1370 };
1371 
1372 /* Recover the outter endpoint structure. */
1373 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1374 {
1375 	struct sctp_endpoint *ep;
1376 
1377 	ep = container_of(base, struct sctp_endpoint, base);
1378 	return ep;
1379 }
1380 
1381 /* These are function signatures for manipulating endpoints.  */
1382 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1383 void sctp_endpoint_free(struct sctp_endpoint *);
1384 void sctp_endpoint_put(struct sctp_endpoint *);
1385 void sctp_endpoint_hold(struct sctp_endpoint *);
1386 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1387 struct sctp_association *sctp_endpoint_lookup_assoc(
1388 	const struct sctp_endpoint *ep,
1389 	const union sctp_addr *paddr,
1390 	struct sctp_transport **);
1391 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1392 				const union sctp_addr *);
1393 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1394 					const union sctp_addr *);
1395 int sctp_has_association(const union sctp_addr *laddr,
1396 			 const union sctp_addr *paddr);
1397 
1398 int sctp_verify_init(const struct sctp_association *asoc, sctp_cid_t,
1399 		     sctp_init_chunk_t *peer_init, struct sctp_chunk *chunk,
1400 		     struct sctp_chunk **err_chunk);
1401 int sctp_process_init(struct sctp_association *, sctp_cid_t cid,
1402 		      const union sctp_addr *peer,
1403 		      sctp_init_chunk_t *init, gfp_t gfp);
1404 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1405 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1406 
1407 struct sctp_inithdr_host {
1408 	__u32 init_tag;
1409 	__u32 a_rwnd;
1410 	__u16 num_outbound_streams;
1411 	__u16 num_inbound_streams;
1412 	__u32 initial_tsn;
1413 };
1414 
1415 /* RFC2960
1416  *
1417  * 12. Recommended Transmission Control Block (TCB) Parameters
1418  *
1419  * This section details a recommended set of parameters that should
1420  * be contained within the TCB for an implementation. This section is
1421  * for illustrative purposes and should not be deemed as requirements
1422  * on an implementation or as an exhaustive list of all parameters
1423  * inside an SCTP TCB. Each implementation may need its own additional
1424  * parameters for optimization.
1425  */
1426 
1427 
1428 /* Here we have information about each individual association. */
1429 struct sctp_association {
1430 
1431 	/* A base structure common to endpoint and association.
1432 	 * In this context, it represents the associations's view
1433 	 * of the local endpoint of the association.
1434 	 */
1435 	struct sctp_ep_common base;
1436 
1437 	/* Associations on the same socket. */
1438 	struct list_head asocs;
1439 
1440 	/* association id. */
1441 	sctp_assoc_t assoc_id;
1442 
1443 	/* This is our parent endpoint.	 */
1444 	struct sctp_endpoint *ep;
1445 
1446 	/* These are those association elements needed in the cookie.  */
1447 	struct sctp_cookie c;
1448 
1449 	/* This is all information about our peer.  */
1450 	struct {
1451 		/* rwnd
1452 		 *
1453 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1454 		 */
1455 		__u32 rwnd;
1456 
1457 		/* transport_addr_list
1458 		 *
1459 		 * Peer	       : A list of SCTP transport addresses that the
1460 		 * Transport   : peer is bound to. This information is derived
1461 		 * Address     : from the INIT or INIT ACK and is used to
1462 		 * List	       : associate an inbound packet with a given
1463 		 *	       : association. Normally this information is
1464 		 *	       : hashed or keyed for quick lookup and access
1465 		 *	       : of the TCB.
1466 		 *	       : The list is also initialized with the list
1467 		 *	       : of addresses passed with the sctp_connectx()
1468 		 *	       : call.
1469 		 *
1470 		 * It is a list of SCTP_transport's.
1471 		 */
1472 		struct list_head transport_addr_list;
1473 
1474 		/* transport_count
1475 		 *
1476 		 * Peer        : A count of the number of peer addresses
1477 		 * Transport   : in the Peer Transport Address List.
1478 		 * Address     :
1479 		 * Count       :
1480 		 */
1481 		__u16 transport_count;
1482 
1483 		/* port
1484 		 *   The transport layer port number.
1485 		 */
1486 		__u16 port;
1487 
1488 		/* primary_path
1489 		 *
1490 		 * Primary     : This is the current primary destination
1491 		 * Path	       : transport address of the peer endpoint.  It
1492 		 *	       : may also specify a source transport address
1493 		 *	       : on this endpoint.
1494 		 *
1495 		 * All of these paths live on transport_addr_list.
1496 		 *
1497 		 * At the bakeoffs, we discovered that the intent of
1498 		 * primaryPath is that it only changes when the ULP
1499 		 * asks to have it changed.  We add the activePath to
1500 		 * designate the connection we are currently using to
1501 		 * transmit new data and most control chunks.
1502 		 */
1503 		struct sctp_transport *primary_path;
1504 
1505 		/* Cache the primary path address here, when we
1506 		 * need a an address for msg_name.
1507 		 */
1508 		union sctp_addr primary_addr;
1509 
1510 		/* active_path
1511 		 *   The path that we are currently using to
1512 		 *   transmit new data and most control chunks.
1513 		 */
1514 		struct sctp_transport *active_path;
1515 
1516 		/* retran_path
1517 		 *
1518 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1519 		 * ...
1520 		 * Furthermore, when its peer is multi-homed, an
1521 		 * endpoint SHOULD try to retransmit a chunk to an
1522 		 * active destination transport address that is
1523 		 * different from the last destination address to
1524 		 * which the DATA chunk was sent.
1525 		 */
1526 		struct sctp_transport *retran_path;
1527 
1528 		/* Pointer to last transport I have sent on.  */
1529 		struct sctp_transport *last_sent_to;
1530 
1531 		/* This is the last transport I have received DATA on.	*/
1532 		struct sctp_transport *last_data_from;
1533 
1534 		/*
1535 		 * Mapping  An array of bits or bytes indicating which out of
1536 		 * Array    order TSN's have been received (relative to the
1537 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1538 		 *	    order packets have been received, this array
1539 		 *	    will be set to all zero. This structure may be
1540 		 *	    in the form of a circular buffer or bit array.
1541 		 *
1542 		 * Last Rcvd   : This is the last TSN received in
1543 		 * TSN	       : sequence. This value is set initially by
1544 		 *	       : taking the peer's Initial TSN, received in
1545 		 *	       : the INIT or INIT ACK chunk, and subtracting
1546 		 *	       : one from it.
1547 		 *
1548 		 * Throughout most of the specification this is called the
1549 		 * "Cumulative TSN ACK Point".	In this case, we
1550 		 * ignore the advice in 12.2 in favour of the term
1551 		 * used in the bulk of the text.  This value is hidden
1552 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1553 		 */
1554 		struct sctp_tsnmap tsn_map;
1555 
1556 		/* Ack State   : This flag indicates if the next received
1557 		 *             : packet is to be responded to with a
1558 		 *             : SACK. This is initializedto 0.  When a packet
1559 		 *             : is received it is incremented. If this value
1560 		 *             : reaches 2 or more, a SACK is sent and the
1561 		 *             : value is reset to 0. Note: This is used only
1562 		 *             : when no DATA chunks are received out of
1563 		 *             : order.  When DATA chunks are out of order,
1564 		 *             : SACK's are not delayed (see Section 6).
1565 		 */
1566 		__u8    sack_needed;     /* Do we need to sack the peer? */
1567 		__u32	sack_cnt;
1568 
1569 		/* These are capabilities which our peer advertised.  */
1570 		__u8	ecn_capable;	 /* Can peer do ECN? */
1571 		__u8	ipv4_address;	 /* Peer understands IPv4 addresses? */
1572 		__u8	ipv6_address;	 /* Peer understands IPv6 addresses? */
1573 		__u8	hostname_address;/* Peer understands DNS addresses? */
1574 		__u8    asconf_capable;  /* Does peer support ADDIP? */
1575 		__u8    prsctp_capable;  /* Can peer do PR-SCTP? */
1576 		__u8	auth_capable;	 /* Is peer doing SCTP-AUTH? */
1577 
1578 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1579 
1580 		/* This mask is used to disable sending the ASCONF chunk
1581 		 * with specified parameter to peer.
1582 		 */
1583 		__be16 addip_disabled_mask;
1584 
1585 		struct sctp_inithdr_host i;
1586 		int cookie_len;
1587 		void *cookie;
1588 
1589 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1590 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1591 		 * Initial TSN Value minus 1
1592 		 */
1593 		__u32 addip_serial;
1594 
1595 		/* SCTP-AUTH: We need to know pears random number, hmac list
1596 		 * and authenticated chunk list.  All that is part of the
1597 		 * cookie and these are just pointers to those locations
1598 		 */
1599 		sctp_random_param_t *peer_random;
1600 		sctp_chunks_param_t *peer_chunks;
1601 		sctp_hmac_algo_param_t *peer_hmacs;
1602 	} peer;
1603 
1604 	/* State       : A state variable indicating what state the
1605 	 *	       : association is in, i.e. COOKIE-WAIT,
1606 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1607 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1608 	 *
1609 	 *		Note: No "CLOSED" state is illustrated since if a
1610 	 *		association is "CLOSED" its TCB SHOULD be removed.
1611 	 *
1612 	 *		In this implementation we DO have a CLOSED
1613 	 *		state which is used during initiation and shutdown.
1614 	 *
1615 	 *		State takes values from SCTP_STATE_*.
1616 	 */
1617 	sctp_state_t state;
1618 
1619 	/* The cookie life I award for any cookie.  */
1620 	struct timeval cookie_life;
1621 
1622 	/* Overall     : The overall association error count.
1623 	 * Error Count : [Clear this any time I get something.]
1624 	 */
1625 	int overall_error_count;
1626 
1627 	/* These are the association's initial, max, and min RTO values.
1628 	 * These values will be initialized by system defaults, but can
1629 	 * be modified via the SCTP_RTOINFO socket option.
1630 	 */
1631 	unsigned long rto_initial;
1632 	unsigned long rto_max;
1633 	unsigned long rto_min;
1634 
1635 	/* Maximum number of new data packets that can be sent in a burst.  */
1636 	int max_burst;
1637 
1638 	/* This is the max_retrans value for the association.  This value will
1639 	 * be initialized initialized from system defaults, but can be
1640 	 * modified by the SCTP_ASSOCINFO socket option.
1641 	 */
1642 	int max_retrans;
1643 
1644 	/* Maximum number of times the endpoint will retransmit INIT  */
1645 	__u16 max_init_attempts;
1646 
1647 	/* How many times have we resent an INIT? */
1648 	__u16 init_retries;
1649 
1650 	/* The largest timeout or RTO value to use in attempting an INIT */
1651 	unsigned long max_init_timeo;
1652 
1653 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1654 	 * the destination address every heartbeat interval. This value
1655 	 * will be inherited by all new transports.
1656 	 */
1657 	unsigned long hbinterval;
1658 
1659 	/* This is the max_retrans value for new transports in the
1660 	 * association.
1661 	 */
1662 	__u16 pathmaxrxt;
1663 
1664 	/* Flag that path mtu update is pending */
1665 	__u8   pmtu_pending;
1666 
1667 	/* Association : The smallest PMTU discovered for all of the
1668 	 * PMTU	       : peer's transport addresses.
1669 	 */
1670 	__u32 pathmtu;
1671 
1672 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1673 	__u32 param_flags;
1674 
1675 	/* SACK delay timeout */
1676 	unsigned long sackdelay;
1677 	__u32 sackfreq;
1678 
1679 
1680 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1681 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1682 
1683 	/* Transport to which SHUTDOWN chunk was last sent.  */
1684 	struct sctp_transport *shutdown_last_sent_to;
1685 
1686 	/* How many times have we resent a SHUTDOWN */
1687 	int shutdown_retries;
1688 
1689 	/* Transport to which INIT chunk was last sent.  */
1690 	struct sctp_transport *init_last_sent_to;
1691 
1692 	/* Next TSN    : The next TSN number to be assigned to a new
1693 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1694 	 *	       : ACK chunk to the peer and incremented each
1695 	 *	       : time a DATA chunk is assigned a TSN
1696 	 *	       : (normally just prior to transmit or during
1697 	 *	       : fragmentation).
1698 	 */
1699 	__u32 next_tsn;
1700 
1701 	/*
1702 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1703 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1704 	 *	       : received in the INIT or INIT ACK chunk, and
1705 	 *	       : subtracting one from it.
1706 	 *
1707 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1708 	 */
1709 
1710 	__u32 ctsn_ack_point;
1711 
1712 	/* PR-SCTP Advanced.Peer.Ack.Point */
1713 	__u32 adv_peer_ack_point;
1714 
1715 	/* Highest TSN that is acknowledged by incoming SACKs. */
1716 	__u32 highest_sacked;
1717 
1718 	/* The number of unacknowledged data chunks.  Reported through
1719 	 * the SCTP_STATUS sockopt.
1720 	 */
1721 	__u16 unack_data;
1722 
1723 	/* The total number of data chunks that we've had to retransmit
1724 	 * as the result of a T3 timer expiration
1725 	 */
1726 	__u32 rtx_data_chunks;
1727 
1728 	/* This is the association's receive buffer space.  This value is used
1729 	 * to set a_rwnd field in an INIT or a SACK chunk.
1730 	 */
1731 	__u32 rwnd;
1732 
1733 	/* This is the last advertised value of rwnd over a SACK chunk. */
1734 	__u32 a_rwnd;
1735 
1736 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1737 	 * to slop over a maximum of the association's frag_point.
1738 	 */
1739 	__u32 rwnd_over;
1740 
1741 	/* This is the sndbuf size in use for the association.
1742 	 * This corresponds to the sndbuf size for the association,
1743 	 * as specified in the sk->sndbuf.
1744 	 */
1745 	int sndbuf_used;
1746 
1747 	/* This is the amount of memory that this association has allocated
1748 	 * in the receive path at any given time.
1749 	 */
1750 	atomic_t rmem_alloc;
1751 
1752 	/* This is the wait queue head for send requests waiting on
1753 	 * the association sndbuf space.
1754 	 */
1755 	wait_queue_head_t	wait;
1756 
1757 	/* The message size at which SCTP fragmentation will occur. */
1758 	__u32 frag_point;
1759 
1760 	/* Counter used to count INIT errors. */
1761 	int init_err_counter;
1762 
1763 	/* Count the number of INIT cycles (for doubling timeout). */
1764 	int init_cycle;
1765 
1766 	/* Default send parameters. */
1767 	__u16 default_stream;
1768 	__u16 default_flags;
1769 	__u32 default_ppid;
1770 	__u32 default_context;
1771 	__u32 default_timetolive;
1772 
1773 	/* Default receive parameters */
1774 	__u32 default_rcv_context;
1775 
1776 	/* This tracks outbound ssn for a given stream.	 */
1777 	struct sctp_ssnmap *ssnmap;
1778 
1779 	/* All outbound chunks go through this structure.  */
1780 	struct sctp_outq outqueue;
1781 
1782 	/* A smart pipe that will handle reordering and fragmentation,
1783 	 * as well as handle passing events up to the ULP.
1784 	 */
1785 	struct sctp_ulpq ulpq;
1786 
1787 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1788 	__u32 last_ecne_tsn;
1789 
1790 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1791 	__u32 last_cwr_tsn;
1792 
1793 	/* How many duplicated TSNs have we seen?  */
1794 	int numduptsns;
1795 
1796 	/* Number of seconds of idle time before an association is closed.
1797 	 * In the association context, this is really used as a boolean
1798 	 * since the real timeout is stored in the timeouts array
1799 	 */
1800 	__u32 autoclose;
1801 
1802 	/* These are to support
1803 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1804 	 *  and Enforcement of Flow and Message Limits"
1805 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1806 	 * or "ADDIP" for short.
1807 	 */
1808 
1809 
1810 
1811 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1812 	 *
1813 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1814 	 * unacknowledged at any one time.  If a sender, after sending
1815 	 * an ASCONF chunk, decides it needs to transfer another
1816 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1817 	 * returns from the previous ASCONF Chunk before sending a
1818 	 * subsequent ASCONF. Note this restriction binds each side,
1819 	 * so at any time two ASCONF may be in-transit on any given
1820 	 * association (one sent from each endpoint).
1821 	 *
1822 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1823 	 * not have an ASCONF in flight, this is NULL.]
1824 	 */
1825 	struct sctp_chunk *addip_last_asconf;
1826 
1827 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1828 	 *
1829 	 * This is needed to implement itmes E1 - E4 of the updated
1830 	 * spec.  Here is the justification:
1831 	 *
1832 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1833 	 * we now need the ability to cache multiple ACKs.  The section
1834 	 * describes in detail how they are cached and cleaned up.
1835 	 */
1836 	struct list_head asconf_ack_list;
1837 
1838 	/* These ASCONF chunks are waiting to be sent.
1839 	 *
1840 	 * These chunaks can't be pushed to outqueue until receiving
1841 	 * ASCONF_ACK for the previous ASCONF indicated by
1842 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1843 	 * is in flight at any time.
1844 	 *
1845 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1846 	 *
1847 	 * In defining the ASCONF Chunk transfer procedures, it is
1848 	 * essential that these transfers MUST NOT cause congestion
1849 	 * within the network.	To achieve this, we place these
1850 	 * restrictions on the transfer of ASCONF Chunks:
1851 	 *
1852 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1853 	 * unacknowledged at any one time.  If a sender, after sending
1854 	 * an ASCONF chunk, decides it needs to transfer another
1855 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1856 	 * returns from the previous ASCONF Chunk before sending a
1857 	 * subsequent ASCONF. Note this restriction binds each side,
1858 	 * so at any time two ASCONF may be in-transit on any given
1859 	 * association (one sent from each endpoint).
1860 	 *
1861 	 *
1862 	 * [I really think this is EXACTLY the sort of intelligence
1863 	 *  which already resides in sctp_outq.	 Please move this
1864 	 *  queue and its supporting logic down there.	--piggy]
1865 	 */
1866 	struct list_head addip_chunk_list;
1867 
1868 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1869 	 *
1870 	 * A2) A serial number should be assigned to the Chunk. The
1871 	 * serial number SHOULD be a monotonically increasing
1872 	 * number. The serial number SHOULD be initialized at
1873 	 * the start of the association to the same value as the
1874 	 * Initial TSN and every time a new ASCONF chunk is created
1875 	 * it is incremented by one after assigning the serial number
1876 	 * to the newly created chunk.
1877 	 *
1878 	 * ADDIP
1879 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1880 	 *
1881 	 * Serial Number : 32 bits (unsigned integer)
1882 	 *
1883 	 * This value represents a Serial Number for the ASCONF
1884 	 * Chunk. The valid range of Serial Number is from 0 to
1885 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1886 	 * after reaching 4294967295.
1887 	 */
1888 	__u32 addip_serial;
1889 
1890 	/* SCTP AUTH: list of the endpoint shared keys.  These
1891 	 * keys are provided out of band by the user applicaton
1892 	 * and can't change during the lifetime of the association
1893 	 */
1894 	struct list_head endpoint_shared_keys;
1895 
1896 	/* SCTP AUTH:
1897 	 * The current generated assocaition shared key (secret)
1898 	 */
1899 	struct sctp_auth_bytes *asoc_shared_key;
1900 
1901 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1902 	 * that we support.
1903 	 */
1904 	__u16 default_hmac_id;
1905 
1906 	__u16 active_key_id;
1907 
1908 	/* Need to send an ECNE Chunk? */
1909 	char need_ecne;
1910 
1911 	/* Is it a temporary association? */
1912 	char temp;
1913 };
1914 
1915 
1916 /* An eyecatcher for determining if we are really looking at an
1917  * association data structure.
1918  */
1919 enum {
1920 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1921 };
1922 
1923 /* Recover the outter association structure. */
1924 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1925 {
1926 	struct sctp_association *asoc;
1927 
1928 	asoc = container_of(base, struct sctp_association, base);
1929 	return asoc;
1930 }
1931 
1932 /* These are function signatures for manipulating associations.	 */
1933 
1934 
1935 struct sctp_association *
1936 sctp_association_new(const struct sctp_endpoint *, const struct sock *,
1937 		     sctp_scope_t scope, gfp_t gfp);
1938 void sctp_association_free(struct sctp_association *);
1939 void sctp_association_put(struct sctp_association *);
1940 void sctp_association_hold(struct sctp_association *);
1941 
1942 struct sctp_transport *sctp_assoc_choose_init_transport(
1943 	struct sctp_association *);
1944 struct sctp_transport *sctp_assoc_choose_shutdown_transport(
1945 	struct sctp_association *);
1946 void sctp_assoc_update_retran_path(struct sctp_association *);
1947 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1948 					  const union sctp_addr *);
1949 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1950 			    const union sctp_addr *laddr);
1951 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
1952 				     const union sctp_addr *address,
1953 				     const gfp_t gfp,
1954 				     const int peer_state);
1955 void sctp_assoc_del_peer(struct sctp_association *asoc,
1956 			 const union sctp_addr *addr);
1957 void sctp_assoc_rm_peer(struct sctp_association *asoc,
1958 			 struct sctp_transport *peer);
1959 void sctp_assoc_control_transport(struct sctp_association *,
1960 				  struct sctp_transport *,
1961 				  sctp_transport_cmd_t, sctp_sn_error_t);
1962 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
1963 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
1964 					   const union sctp_addr *,
1965 					   const union sctp_addr *);
1966 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
1967 void sctp_assoc_update(struct sctp_association *old,
1968 		       struct sctp_association *new);
1969 
1970 __u32 sctp_association_get_next_tsn(struct sctp_association *);
1971 
1972 void sctp_assoc_sync_pmtu(struct sctp_association *);
1973 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned);
1974 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned);
1975 void sctp_assoc_set_primary(struct sctp_association *,
1976 			    struct sctp_transport *);
1977 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
1978 				    struct sctp_transport *);
1979 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
1980 				     gfp_t);
1981 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
1982 					 struct sctp_cookie*,
1983 					 gfp_t gfp);
1984 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
1985 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
1986 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1987 					const struct sctp_association *asoc,
1988 					__be32 serial);
1989 
1990 
1991 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
1992 			const union sctp_addr *ss2);
1993 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
1994 
1995 /* A convenience structure to parse out SCTP specific CMSGs. */
1996 typedef struct sctp_cmsgs {
1997 	struct sctp_initmsg *init;
1998 	struct sctp_sndrcvinfo *info;
1999 } sctp_cmsgs_t;
2000 
2001 /* Structure for tracking memory objects */
2002 typedef struct {
2003 	char *label;
2004 	atomic_t *counter;
2005 } sctp_dbg_objcnt_entry_t;
2006 
2007 #endif /* __sctp_structs_h__ */
2008