xref: /linux/include/net/sctp/structs.h (revision eedb3c44313ae0785e1dc62c6910557953887388)
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, see
23  * <http://www.gnu.org/licenses/>.
24  *
25  * Please send any bug reports or fixes you make to the
26  * email addresses:
27  *    lksctp developers <linux-sctp@vger.kernel.org>
28  *
29  * Written or modified by:
30  *    Randall Stewart	    <randall@sctp.chicago.il.us>
31  *    Ken Morneau	    <kmorneau@cisco.com>
32  *    Qiaobing Xie	    <qxie1@email.mot.com>
33  *    La Monte H.P. Yarroll <piggy@acm.org>
34  *    Karl Knutson	    <karl@athena.chicago.il.us>
35  *    Jon Grimm		    <jgrimm@us.ibm.com>
36  *    Xingang Guo	    <xingang.guo@intel.com>
37  *    Hui Huang		    <hui.huang@nokia.com>
38  *    Sridhar Samudrala	    <sri@us.ibm.com>
39  *    Daisy Chang	    <daisyc@us.ibm.com>
40  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
41  *    Ardelle Fan	    <ardelle.fan@intel.com>
42  *    Ryan Layer	    <rmlayer@us.ibm.com>
43  *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
44  *    Kevin Gao             <kevin.gao@intel.com>
45  */
46 
47 #ifndef __sctp_structs_h__
48 #define __sctp_structs_h__
49 
50 #include <linux/ktime.h>
51 #include <linux/rhashtable.h>
52 #include <linux/socket.h>	/* linux/in.h needs this!!    */
53 #include <linux/in.h>		/* We get struct sockaddr_in. */
54 #include <linux/in6.h>		/* We get struct in6_addr     */
55 #include <linux/ipv6.h>
56 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
57 #include <linux/atomic.h>		/* This gets us atomic counters.  */
58 #include <linux/skbuff.h>	/* We need sk_buff_head. */
59 #include <linux/workqueue.h>	/* We need tq_struct.	 */
60 #include <linux/sctp.h>		/* We need sctp* header structs.  */
61 #include <net/sctp/auth.h>	/* We need auth specific structs */
62 #include <net/ip.h>		/* For inet_skb_parm */
63 
64 /* A convenience structure for handling sockaddr structures.
65  * We should wean ourselves off this.
66  */
67 union sctp_addr {
68 	struct sockaddr_in v4;
69 	struct sockaddr_in6 v6;
70 	struct sockaddr sa;
71 };
72 
73 /* Forward declarations for data structures. */
74 struct sctp_globals;
75 struct sctp_endpoint;
76 struct sctp_association;
77 struct sctp_transport;
78 struct sctp_packet;
79 struct sctp_chunk;
80 struct sctp_inq;
81 struct sctp_outq;
82 struct sctp_bind_addr;
83 struct sctp_ulpq;
84 struct sctp_ep_common;
85 struct crypto_shash;
86 
87 
88 #include <net/sctp/tsnmap.h>
89 #include <net/sctp/ulpevent.h>
90 #include <net/sctp/ulpqueue.h>
91 
92 /* Structures useful for managing bind/connect. */
93 
94 struct sctp_bind_bucket {
95 	unsigned short	port;
96 	unsigned short	fastreuse;
97 	struct hlist_node	node;
98 	struct hlist_head	owner;
99 	struct net	*net;
100 };
101 
102 struct sctp_bind_hashbucket {
103 	spinlock_t	lock;
104 	struct hlist_head	chain;
105 };
106 
107 /* Used for hashing all associations.  */
108 struct sctp_hashbucket {
109 	rwlock_t	lock;
110 	struct hlist_head	chain;
111 } __attribute__((__aligned__(8)));
112 
113 
114 /* The SCTP globals structure. */
115 extern struct sctp_globals {
116 	/* This is a list of groups of functions for each address
117 	 * family that we support.
118 	 */
119 	struct list_head address_families;
120 
121 	/* This is the hash of all endpoints. */
122 	struct sctp_hashbucket *ep_hashtable;
123 	/* This is the sctp port control hash.	*/
124 	struct sctp_bind_hashbucket *port_hashtable;
125 	/* This is the hash of all transports. */
126 	struct rhltable transport_hashtable;
127 
128 	/* Sizes of above hashtables. */
129 	int ep_hashsize;
130 	int port_hashsize;
131 
132 	/* Default initialization values to be applied to new associations. */
133 	__u16 max_instreams;
134 	__u16 max_outstreams;
135 
136 	/* Flag to indicate whether computing and verifying checksum
137 	 * is disabled. */
138         bool checksum_disable;
139 } sctp_globals;
140 
141 #define sctp_max_instreams		(sctp_globals.max_instreams)
142 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
143 #define sctp_address_families		(sctp_globals.address_families)
144 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
145 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
146 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
147 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
148 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
149 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
150 
151 /* SCTP Socket type: UDP or TCP style. */
152 typedef enum {
153 	SCTP_SOCKET_UDP = 0,
154 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
155 	SCTP_SOCKET_TCP
156 } sctp_socket_type_t;
157 
158 /* Per socket SCTP information. */
159 struct sctp_sock {
160 	/* inet_sock has to be the first member of sctp_sock */
161 	struct inet_sock inet;
162 	/* What kind of a socket is this? */
163 	sctp_socket_type_t type;
164 
165 	/* PF_ family specific functions.  */
166 	struct sctp_pf *pf;
167 
168 	/* Access to HMAC transform. */
169 	struct crypto_shash *hmac;
170 	char *sctp_hmac_alg;
171 
172 	/* What is our base endpointer? */
173 	struct sctp_endpoint *ep;
174 
175 	struct sctp_bind_bucket *bind_hash;
176 	/* Various Socket Options.  */
177 	__u16 default_stream;
178 	__u32 default_ppid;
179 	__u16 default_flags;
180 	__u32 default_context;
181 	__u32 default_timetolive;
182 	__u32 default_rcv_context;
183 	int max_burst;
184 
185 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
186 	 * the destination address every heartbeat interval. This value
187 	 * will be inherited by all new associations.
188 	 */
189 	__u32 hbinterval;
190 
191 	/* This is the max_retrans value for new associations. */
192 	__u16 pathmaxrxt;
193 
194 	/* The initial Path MTU to use for new associations. */
195 	__u32 pathmtu;
196 
197 	/* The default SACK delay timeout for new associations. */
198 	__u32 sackdelay;
199 	__u32 sackfreq;
200 
201 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
202 	__u32 param_flags;
203 
204 	struct sctp_initmsg initmsg;
205 	struct sctp_rtoinfo rtoinfo;
206 	struct sctp_paddrparams paddrparam;
207 	struct sctp_event_subscribe subscribe;
208 	struct sctp_assocparams assocparams;
209 
210 	int user_frag;
211 
212 	__u32 autoclose;
213 	__u32 adaptation_ind;
214 	__u32 pd_point;
215 	__u16	nodelay:1,
216 		disable_fragments:1,
217 		v4mapped:1,
218 		frag_interleave:1,
219 		recvrcvinfo:1,
220 		recvnxtinfo:1,
221 		data_ready_signalled:1;
222 
223 	atomic_t pd_mode;
224 	/* Receive to here while partial delivery is in effect. */
225 	struct sk_buff_head pd_lobby;
226 
227 	/* These must be the last fields, as they will skipped on copies,
228 	 * like on accept and peeloff operations
229 	 */
230 	struct list_head auto_asconf_list;
231 	int do_auto_asconf;
232 };
233 
234 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
235 {
236        return (struct sctp_sock *)sk;
237 }
238 
239 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
240 {
241        return (struct sock *)sp;
242 }
243 
244 #if IS_ENABLED(CONFIG_IPV6)
245 struct sctp6_sock {
246        struct sctp_sock  sctp;
247        struct ipv6_pinfo inet6;
248 };
249 #endif /* CONFIG_IPV6 */
250 
251 
252 /* This is our APPLICATION-SPECIFIC state cookie.
253  * THIS IS NOT DICTATED BY THE SPECIFICATION.
254  */
255 /* These are the parts of an association which we send in the cookie.
256  * Most of these are straight out of:
257  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
258  *
259  */
260 
261 struct sctp_cookie {
262 
263 	/* My	       : Tag expected in every inbound packet and sent
264 	 * Verification: in the INIT or INIT ACK chunk.
265 	 * Tag	       :
266 	 */
267 	__u32 my_vtag;
268 
269 	/* Peer's      : Tag expected in every outbound packet except
270 	 * Verification: in the INIT chunk.
271 	 * Tag	       :
272 	 */
273 	__u32 peer_vtag;
274 
275 	/* The rest of these are not from the spec, but really need to
276 	 * be in the cookie.
277 	 */
278 
279 	/* My Tie Tag  : Assist in discovering a restarting association. */
280 	__u32 my_ttag;
281 
282 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
283 	__u32 peer_ttag;
284 
285 	/* When does this cookie expire? */
286 	ktime_t expiration;
287 
288 	/* Number of inbound/outbound streams which are set
289 	 * and negotiated during the INIT process.
290 	 */
291 	__u16 sinit_num_ostreams;
292 	__u16 sinit_max_instreams;
293 
294 	/* This is the first sequence number I used.  */
295 	__u32 initial_tsn;
296 
297 	/* This holds the originating address of the INIT packet.  */
298 	union sctp_addr peer_addr;
299 
300 	/* IG Section 2.35.3
301 	 * Include the source port of the INIT-ACK
302 	 */
303 	__u16		my_port;
304 
305 	__u8 prsctp_capable;
306 
307 	/* Padding for future use */
308 	__u8 padding;
309 
310 	__u32 adaptation_ind;
311 
312 	__u8 auth_random[sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH];
313 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
314 	__u8 auth_chunks[sizeof(sctp_paramhdr_t) + SCTP_AUTH_MAX_CHUNKS];
315 
316 	/* This is a shim for my peer's INIT packet, followed by
317 	 * a copy of the raw address list of the association.
318 	 * The length of the raw address list is saved in the
319 	 * raw_addr_list_len field, which will be used at the time when
320 	 * the association TCB is re-constructed from the cookie.
321 	 */
322 	__u32 raw_addr_list_len;
323 	struct sctp_init_chunk peer_init[0];
324 };
325 
326 
327 /* The format of our cookie that we send to our peer. */
328 struct sctp_signed_cookie {
329 	__u8 signature[SCTP_SECRET_SIZE];
330 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
331 	struct sctp_cookie c;
332 } __packed;
333 
334 /* This is another convenience type to allocate memory for address
335  * params for the maximum size and pass such structures around
336  * internally.
337  */
338 union sctp_addr_param {
339 	struct sctp_paramhdr p;
340 	struct sctp_ipv4addr_param v4;
341 	struct sctp_ipv6addr_param v6;
342 };
343 
344 /* A convenience type to allow walking through the various
345  * parameters and avoid casting all over the place.
346  */
347 union sctp_params {
348 	void *v;
349 	struct sctp_paramhdr *p;
350 	struct sctp_cookie_preserve_param *life;
351 	struct sctp_hostname_param *dns;
352 	struct sctp_cookie_param *cookie;
353 	struct sctp_supported_addrs_param *sat;
354 	struct sctp_ipv4addr_param *v4;
355 	struct sctp_ipv6addr_param *v6;
356 	union sctp_addr_param *addr;
357 	struct sctp_adaptation_ind_param *aind;
358 	struct sctp_supported_ext_param *ext;
359 	struct sctp_random_param *random;
360 	struct sctp_chunks_param *chunks;
361 	struct sctp_hmac_algo_param *hmac_algo;
362 	struct sctp_addip_param *addip;
363 };
364 
365 /* RFC 2960.  Section 3.3.5 Heartbeat.
366  *    Heartbeat Information: variable length
367  *    The Sender-specific Heartbeat Info field should normally include
368  *    information about the sender's current time when this HEARTBEAT
369  *    chunk is sent and the destination transport address to which this
370  *    HEARTBEAT is sent (see Section 8.3).
371  */
372 typedef struct sctp_sender_hb_info {
373 	struct sctp_paramhdr param_hdr;
374 	union sctp_addr daddr;
375 	unsigned long sent_at;
376 	__u64 hb_nonce;
377 } sctp_sender_hb_info_t;
378 
379 struct sctp_stream *sctp_stream_new(__u16 incnt, __u16 outcnt, gfp_t gfp);
380 void sctp_stream_free(struct sctp_stream *stream);
381 void sctp_stream_clear(struct sctp_stream *stream);
382 
383 /* What is the current SSN number for this stream? */
384 #define sctp_ssn_peek(stream, type, sid) \
385 	((stream)->type[sid].ssn)
386 
387 /* Return the next SSN number for this stream.	*/
388 #define sctp_ssn_next(stream, type, sid) \
389 	((stream)->type[sid].ssn++)
390 
391 /* Skip over this ssn and all below. */
392 #define sctp_ssn_skip(stream, type, sid, ssn) \
393 	((stream)->type[sid].ssn = ssn + 1)
394 
395 /*
396  * Pointers to address related SCTP functions.
397  * (i.e. things that depend on the address family.)
398  */
399 struct sctp_af {
400 	int		(*sctp_xmit)	(struct sk_buff *skb,
401 					 struct sctp_transport *);
402 	int		(*setsockopt)	(struct sock *sk,
403 					 int level,
404 					 int optname,
405 					 char __user *optval,
406 					 unsigned int optlen);
407 	int		(*getsockopt)	(struct sock *sk,
408 					 int level,
409 					 int optname,
410 					 char __user *optval,
411 					 int __user *optlen);
412 	int		(*compat_setsockopt)	(struct sock *sk,
413 					 int level,
414 					 int optname,
415 					 char __user *optval,
416 					 unsigned int optlen);
417 	int		(*compat_getsockopt)	(struct sock *sk,
418 					 int level,
419 					 int optname,
420 					 char __user *optval,
421 					 int __user *optlen);
422 	void		(*get_dst)	(struct sctp_transport *t,
423 					 union sctp_addr *saddr,
424 					 struct flowi *fl,
425 					 struct sock *sk);
426 	void		(*get_saddr)	(struct sctp_sock *sk,
427 					 struct sctp_transport *t,
428 					 struct flowi *fl);
429 	void		(*copy_addrlist) (struct list_head *,
430 					  struct net_device *);
431 	int		(*cmp_addr)	(const union sctp_addr *addr1,
432 					 const union sctp_addr *addr2);
433 	void		(*addr_copy)	(union sctp_addr *dst,
434 					 union sctp_addr *src);
435 	void		(*from_skb)	(union sctp_addr *,
436 					 struct sk_buff *skb,
437 					 int saddr);
438 	void		(*from_sk)	(union sctp_addr *,
439 					 struct sock *sk);
440 	void		(*from_addr_param) (union sctp_addr *,
441 					    union sctp_addr_param *,
442 					    __be16 port, int iif);
443 	int		(*to_addr_param) (const union sctp_addr *,
444 					  union sctp_addr_param *);
445 	int		(*addr_valid)	(union sctp_addr *,
446 					 struct sctp_sock *,
447 					 const struct sk_buff *);
448 	sctp_scope_t	(*scope) (union sctp_addr *);
449 	void		(*inaddr_any)	(union sctp_addr *, __be16);
450 	int		(*is_any)	(const union sctp_addr *);
451 	int		(*available)	(union sctp_addr *,
452 					 struct sctp_sock *);
453 	int		(*skb_iif)	(const struct sk_buff *sk);
454 	int		(*is_ce)	(const struct sk_buff *sk);
455 	void		(*seq_dump_addr)(struct seq_file *seq,
456 					 union sctp_addr *addr);
457 	void		(*ecn_capable)(struct sock *sk);
458 	__u16		net_header_len;
459 	int		sockaddr_len;
460 	sa_family_t	sa_family;
461 	struct list_head list;
462 };
463 
464 struct sctp_af *sctp_get_af_specific(sa_family_t);
465 int sctp_register_af(struct sctp_af *);
466 
467 /* Protocol family functions. */
468 struct sctp_pf {
469 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
470 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
471 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
472 	int  (*cmp_addr) (const union sctp_addr *,
473 			  const union sctp_addr *,
474 			  struct sctp_sock *);
475 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
476 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
477 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
478 	struct sock *(*create_accept_sk) (struct sock *sk,
479 					  struct sctp_association *asoc,
480 					  bool kern);
481 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
482 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
483 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
484 	struct sctp_af *af;
485 };
486 
487 
488 /* Structure to track chunk fragments that have been acked, but peer
489  * fragments of the same message have not.
490  */
491 struct sctp_datamsg {
492 	/* Chunks waiting to be submitted to lower layer. */
493 	struct list_head chunks;
494 	/* Reference counting. */
495 	atomic_t refcnt;
496 	/* When is this message no longer interesting to the peer? */
497 	unsigned long expires_at;
498 	/* Did the messenge fail to send? */
499 	int send_error;
500 	u8 send_failed:1,
501 	   force_delay:1,
502 	   can_delay;	    /* should this message be Nagle delayed */
503 };
504 
505 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
506 					    struct sctp_sndrcvinfo *,
507 					    struct iov_iter *);
508 void sctp_datamsg_free(struct sctp_datamsg *);
509 void sctp_datamsg_put(struct sctp_datamsg *);
510 void sctp_chunk_fail(struct sctp_chunk *, int error);
511 int sctp_chunk_abandoned(struct sctp_chunk *);
512 
513 /* RFC2960 1.4 Key Terms
514  *
515  * o Chunk: A unit of information within an SCTP packet, consisting of
516  * a chunk header and chunk-specific content.
517  *
518  * As a matter of convenience, we remember the SCTP common header for
519  * each chunk as well as a few other header pointers...
520  */
521 struct sctp_chunk {
522 	struct list_head list;
523 
524 	atomic_t refcnt;
525 
526 	/* How many times this chunk have been sent, for prsctp RTX policy */
527 	int sent_count;
528 
529 	/* This is our link to the per-transport transmitted list.  */
530 	struct list_head transmitted_list;
531 
532 	/* This field is used by chunks that hold fragmented data.
533 	 * For the first fragment this is the list that holds the rest of
534 	 * fragments. For the remaining fragments, this is the link to the
535 	 * frag_list maintained in the first fragment.
536 	 */
537 	struct list_head frag_list;
538 
539 	/* This points to the sk_buff containing the actual data.  */
540 	struct sk_buff *skb;
541 
542 	/* In case of GSO packets, this will store the head one */
543 	struct sk_buff *head_skb;
544 
545 	/* These are the SCTP headers by reverse order in a packet.
546 	 * Note that some of these may happen more than once.  In that
547 	 * case, we point at the "current" one, whatever that means
548 	 * for that level of header.
549 	 */
550 
551 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
552 	union sctp_params param_hdr;
553 	union {
554 		__u8 *v;
555 		struct sctp_datahdr *data_hdr;
556 		struct sctp_inithdr *init_hdr;
557 		struct sctp_sackhdr *sack_hdr;
558 		struct sctp_heartbeathdr *hb_hdr;
559 		struct sctp_sender_hb_info *hbs_hdr;
560 		struct sctp_shutdownhdr *shutdown_hdr;
561 		struct sctp_signed_cookie *cookie_hdr;
562 		struct sctp_ecnehdr *ecne_hdr;
563 		struct sctp_cwrhdr *ecn_cwr_hdr;
564 		struct sctp_errhdr *err_hdr;
565 		struct sctp_addiphdr *addip_hdr;
566 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
567 		struct sctp_authhdr *auth_hdr;
568 	} subh;
569 
570 	__u8 *chunk_end;
571 
572 	struct sctp_chunkhdr *chunk_hdr;
573 	struct sctphdr *sctp_hdr;
574 
575 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
576 	struct sctp_sndrcvinfo sinfo;
577 
578 	/* Which association does this belong to?  */
579 	struct sctp_association *asoc;
580 
581 	/* What endpoint received this chunk? */
582 	struct sctp_ep_common *rcvr;
583 
584 	/* We fill this in if we are calculating RTT. */
585 	unsigned long sent_at;
586 
587 	/* What is the origin IP address for this chunk?  */
588 	union sctp_addr source;
589 	/* Destination address for this chunk. */
590 	union sctp_addr dest;
591 
592 	/* For outbound message, track all fragments for SEND_FAILED. */
593 	struct sctp_datamsg *msg;
594 
595 	/* For an inbound chunk, this tells us where it came from.
596 	 * For an outbound chunk, it tells us where we'd like it to
597 	 * go.	It is NULL if we have no preference.
598 	 */
599 	struct sctp_transport *transport;
600 
601 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
602 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
603 	 * spec violates the principle premis that all chunks are processed
604 	 * in order.
605 	 */
606 	struct sk_buff *auth_chunk;
607 
608 #define SCTP_CAN_FRTX 0x0
609 #define SCTP_NEED_FRTX 0x1
610 #define SCTP_DONT_FRTX 0x2
611 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
612 		has_tsn:1,		/* Does this chunk have a TSN yet? */
613 		has_ssn:1,		/* Does this chunk have a SSN yet? */
614 		singleton:1,		/* Only chunk in the packet? */
615 		end_of_packet:1,	/* Last chunk in the packet? */
616 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
617 		pdiscard:1,		/* Discard the whole packet now? */
618 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
619 		data_accepted:1,	/* At least 1 chunk accepted */
620 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
621 		has_asconf:1,		/* IN: have seen an asconf before */
622 		tsn_missing_report:2,	/* Data chunk missing counter. */
623 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
624 };
625 
626 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
627 void sctp_chunk_hold(struct sctp_chunk *);
628 void sctp_chunk_put(struct sctp_chunk *);
629 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
630 			  struct iov_iter *from);
631 void sctp_chunk_free(struct sctp_chunk *);
632 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
633 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
634 				 const struct sctp_association *,
635 				 struct sock *, gfp_t gfp);
636 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
637 		     union sctp_addr *);
638 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
639 
640 enum {
641 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
642 	SCTP_ADDR_SRC,		/* address can be used as source */
643 	SCTP_ADDR_DEL,		/* address about to be deleted */
644 };
645 
646 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
647 struct sctp_sockaddr_entry {
648 	struct list_head list;
649 	struct rcu_head	rcu;
650 	union sctp_addr a;
651 	__u8 state;
652 	__u8 valid;
653 };
654 
655 #define SCTP_ADDRESS_TICK_DELAY	500
656 
657 typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);
658 
659 /* This structure holds lists of chunks as we are assembling for
660  * transmission.
661  */
662 struct sctp_packet {
663 	/* These are the SCTP header values (host order) for the packet. */
664 	__u16 source_port;
665 	__u16 destination_port;
666 	__u32 vtag;
667 
668 	/* This contains the payload chunks.  */
669 	struct list_head chunk_list;
670 
671 	/* This is the overhead of the sctp and ip headers. */
672 	size_t overhead;
673 	/* This is the total size of all chunks INCLUDING padding.  */
674 	size_t size;
675 	/* This is the maximum size this packet may have */
676 	size_t max_size;
677 
678 	/* The packet is destined for this transport address.
679 	 * The function we finally use to pass down to the next lower
680 	 * layer lives in the transport structure.
681 	 */
682 	struct sctp_transport *transport;
683 
684 	/* pointer to the auth chunk for this packet */
685 	struct sctp_chunk *auth;
686 
687 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
688 	    has_sack:1,		/* This packet contains a SACK chunk. */
689 	    has_auth:1,		/* This packet contains an AUTH chunk */
690 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
691 	    ipfragok:1;		/* So let ip fragment this packet */
692 };
693 
694 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
695 		      __u16 sport, __u16 dport);
696 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
697 sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *,
698 				       struct sctp_chunk *, int, gfp_t);
699 sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *,
700                                      struct sctp_chunk *);
701 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
702 void sctp_packet_free(struct sctp_packet *);
703 
704 static inline int sctp_packet_empty(struct sctp_packet *packet)
705 {
706 	return packet->size == packet->overhead;
707 }
708 
709 /* This represents a remote transport address.
710  * For local transport addresses, we just use union sctp_addr.
711  *
712  * RFC2960 Section 1.4 Key Terms
713  *
714  *   o	Transport address:  A Transport Address is traditionally defined
715  *	by Network Layer address, Transport Layer protocol and Transport
716  *	Layer port number.  In the case of SCTP running over IP, a
717  *	transport address is defined by the combination of an IP address
718  *	and an SCTP port number (where SCTP is the Transport protocol).
719  *
720  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
721  *
722  *   o	The sender keeps a separate congestion control parameter set for
723  *	each of the destination addresses it can send to (not each
724  *	source-destination pair but for each destination).  The parameters
725  *	should decay if the address is not used for a long enough time
726  *	period.
727  *
728  */
729 struct sctp_transport {
730 	/* A list of transports. */
731 	struct list_head transports;
732 	struct rhlist_head node;
733 
734 	/* Reference counting. */
735 	atomic_t refcnt;
736 		/* RTO-Pending : A flag used to track if one of the DATA
737 		 *		chunks sent to this address is currently being
738 		 *		used to compute a RTT. If this flag is 0,
739 		 *		the next DATA chunk sent to this destination
740 		 *		should be used to compute a RTT and this flag
741 		 *		should be set. Every time the RTT
742 		 *		calculation completes (i.e. the DATA chunk
743 		 *		is SACK'd) clear this flag.
744 		 */
745 	__u32	rto_pending:1,
746 
747 		/*
748 		 * hb_sent : a flag that signals that we have a pending
749 		 * heartbeat.
750 		 */
751 		hb_sent:1,
752 
753 		/* Is the Path MTU update pending on this tranport */
754 		pmtu_pending:1,
755 
756 		/* Has this transport moved the ctsn since we last sacked */
757 		sack_generation:1;
758 	u32 dst_cookie;
759 
760 	struct flowi fl;
761 
762 	/* This is the peer's IP address and port. */
763 	union sctp_addr ipaddr;
764 
765 	/* These are the functions we call to handle LLP stuff.	 */
766 	struct sctp_af *af_specific;
767 
768 	/* Which association do we belong to?  */
769 	struct sctp_association *asoc;
770 
771 	/* RFC2960
772 	 *
773 	 * 12.3 Per Transport Address Data
774 	 *
775 	 * For each destination transport address in the peer's
776 	 * address list derived from the INIT or INIT ACK chunk, a
777 	 * number of data elements needs to be maintained including:
778 	 */
779 	/* RTO	       : The current retransmission timeout value.  */
780 	unsigned long rto;
781 
782 	__u32 rtt;		/* This is the most recent RTT.	 */
783 
784 	/* RTTVAR      : The current RTT variation.  */
785 	__u32 rttvar;
786 
787 	/* SRTT	       : The current smoothed round trip time.	*/
788 	__u32 srtt;
789 
790 	/*
791 	 * These are the congestion stats.
792 	 */
793 	/* cwnd	       : The current congestion window.	 */
794 	__u32 cwnd;		  /* This is the actual cwnd.  */
795 
796 	/* ssthresh    : The current slow start threshold value.  */
797 	__u32 ssthresh;
798 
799 	/* partial     : The tracking method for increase of cwnd when in
800 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
801 	 */
802 	__u32 partial_bytes_acked;
803 
804 	/* Data that has been sent, but not acknowledged. */
805 	__u32 flight_size;
806 
807 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
808 
809 	__u32 dst_pending_confirm;	/* need to confirm neighbour */
810 
811 	/* Destination */
812 	struct dst_entry *dst;
813 	/* Source address. */
814 	union sctp_addr saddr;
815 
816 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
817 	 * the destination address every heartbeat interval.
818 	 */
819 	unsigned long hbinterval;
820 
821 	/* SACK delay timeout */
822 	unsigned long sackdelay;
823 	__u32 sackfreq;
824 
825 	/* When was the last time that we heard from this transport? We use
826 	 * this to pick new active and retran paths.
827 	 */
828 	ktime_t last_time_heard;
829 
830 	/* When was the last time that we sent a chunk using this
831 	 * transport? We use this to check for idle transports
832 	 */
833 	unsigned long last_time_sent;
834 
835 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
836 	 * indication based on ECNE chunk.
837 	 */
838 	unsigned long last_time_ecne_reduced;
839 
840 	/* This is the max_retrans value for the transport and will
841 	 * be initialized from the assocs value.  This can be changed
842 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
843 	 */
844 	__u16 pathmaxrxt;
845 
846 	/* This is the partially failed retrans value for the transport
847 	 * and will be initialized from the assocs value.  This can be changed
848 	 * using the SCTP_PEER_ADDR_THLDS socket option
849 	 */
850 	int pf_retrans;
851 	/* PMTU	      : The current known path MTU.  */
852 	__u32 pathmtu;
853 
854 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
855 	__u32 param_flags;
856 
857 	/* The number of times INIT has been sent on this transport. */
858 	int init_sent_count;
859 
860 	/* state       : The current state of this destination,
861 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
862 	 */
863 	int state;
864 
865 	/* These are the error stats for this destination.  */
866 
867 	/* Error count : The current error count for this destination.	*/
868 	unsigned short error_count;
869 
870 	/* Per	       : A timer used by each destination.
871 	 * Destination :
872 	 * Timer       :
873 	 *
874 	 * [Everywhere else in the text this is called T3-rtx. -ed]
875 	 */
876 	struct timer_list T3_rtx_timer;
877 
878 	/* Heartbeat timer is per destination. */
879 	struct timer_list hb_timer;
880 
881 	/* Timer to handle ICMP proto unreachable envets */
882 	struct timer_list proto_unreach_timer;
883 
884 	/* Timer to handler reconf chunk rtx */
885 	struct timer_list reconf_timer;
886 
887 	/* Since we're using per-destination retransmission timers
888 	 * (see above), we're also using per-destination "transmitted"
889 	 * queues.  This probably ought to be a private struct
890 	 * accessible only within the outqueue, but it's not, yet.
891 	 */
892 	struct list_head transmitted;
893 
894 	/* We build bundle-able packets for this transport here.  */
895 	struct sctp_packet packet;
896 
897 	/* This is the list of transports that have chunks to send.  */
898 	struct list_head send_ready;
899 
900 	/* State information saved for SFR_CACC algorithm. The key
901 	 * idea in SFR_CACC is to maintain state at the sender on a
902 	 * per-destination basis when a changeover happens.
903 	 *	char changeover_active;
904 	 *	char cycling_changeover;
905 	 *	__u32 next_tsn_at_change;
906 	 *	char cacc_saw_newack;
907 	 */
908 	struct {
909 		/* An unsigned integer, which stores the next TSN to be
910 		 * used by the sender, at the moment of changeover.
911 		 */
912 		__u32 next_tsn_at_change;
913 
914 		/* A flag which indicates the occurrence of a changeover */
915 		char changeover_active;
916 
917 		/* A flag which indicates whether the change of primary is
918 		 * the first switch to this destination address during an
919 		 * active switch.
920 		 */
921 		char cycling_changeover;
922 
923 		/* A temporary flag, which is used during the processing of
924 		 * a SACK to estimate the causative TSN(s)'s group.
925 		 */
926 		char cacc_saw_newack;
927 	} cacc;
928 
929 	/* 64-bit random number sent with heartbeat. */
930 	__u64 hb_nonce;
931 
932 	struct rcu_head rcu;
933 };
934 
935 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
936 					  gfp_t);
937 void sctp_transport_set_owner(struct sctp_transport *,
938 			      struct sctp_association *);
939 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
940 			  struct sctp_sock *);
941 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
942 void sctp_transport_free(struct sctp_transport *);
943 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
944 void sctp_transport_reset_hb_timer(struct sctp_transport *);
945 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
946 int sctp_transport_hold(struct sctp_transport *);
947 void sctp_transport_put(struct sctp_transport *);
948 void sctp_transport_update_rto(struct sctp_transport *, __u32);
949 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
950 void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
951 void sctp_transport_burst_limited(struct sctp_transport *);
952 void sctp_transport_burst_reset(struct sctp_transport *);
953 unsigned long sctp_transport_timeout(struct sctp_transport *);
954 void sctp_transport_reset(struct sctp_transport *);
955 void sctp_transport_update_pmtu(struct sock *, struct sctp_transport *, u32);
956 void sctp_transport_immediate_rtx(struct sctp_transport *);
957 void sctp_transport_dst_release(struct sctp_transport *t);
958 void sctp_transport_dst_confirm(struct sctp_transport *t);
959 
960 
961 /* This is the structure we use to queue packets as they come into
962  * SCTP.  We write packets to it and read chunks from it.
963  */
964 struct sctp_inq {
965 	/* This is actually a queue of sctp_chunk each
966 	 * containing a partially decoded packet.
967 	 */
968 	struct list_head in_chunk_list;
969 	/* This is the packet which is currently off the in queue and is
970 	 * being worked on through the inbound chunk processing.
971 	 */
972 	struct sctp_chunk *in_progress;
973 
974 	/* This is the delayed task to finish delivering inbound
975 	 * messages.
976 	 */
977 	struct work_struct immediate;
978 };
979 
980 void sctp_inq_init(struct sctp_inq *);
981 void sctp_inq_free(struct sctp_inq *);
982 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
983 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
984 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
985 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
986 
987 /* This is the structure we use to hold outbound chunks.  You push
988  * chunks in and they automatically pop out the other end as bundled
989  * packets (it calls (*output_handler)()).
990  *
991  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
992  * and 8.2 of the v13 draft.
993  *
994  * It handles retransmissions.	The connection to the timeout portion
995  * of the state machine is through sctp_..._timeout() and timeout_handler.
996  *
997  * If you feed it SACKs, it will eat them.
998  *
999  * If you give it big chunks, it will fragment them.
1000  *
1001  * It assigns TSN's to data chunks.  This happens at the last possible
1002  * instant before transmission.
1003  *
1004  * When free()'d, it empties itself out via output_handler().
1005  */
1006 struct sctp_outq {
1007 	struct sctp_association *asoc;
1008 
1009 	/* Data pending that has never been transmitted.  */
1010 	struct list_head out_chunk_list;
1011 
1012 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1013 
1014 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1015 	unsigned int error;
1016 
1017 	/* These are control chunks we want to send.  */
1018 	struct list_head control_chunk_list;
1019 
1020 	/* These are chunks that have been sacked but are above the
1021 	 * CTSN, or cumulative tsn ack point.
1022 	 */
1023 	struct list_head sacked;
1024 
1025 	/* Put chunks on this list to schedule them for
1026 	 * retransmission.
1027 	 */
1028 	struct list_head retransmit;
1029 
1030 	/* Put chunks on this list to save them for FWD TSN processing as
1031 	 * they were abandoned.
1032 	 */
1033 	struct list_head abandoned;
1034 
1035 	/* How many unackd bytes do we have in-flight?	*/
1036 	__u32 outstanding_bytes;
1037 
1038 	/* Are we doing fast-rtx on this queue */
1039 	char fast_rtx;
1040 
1041 	/* Corked? */
1042 	char cork;
1043 };
1044 
1045 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1046 void sctp_outq_teardown(struct sctp_outq *);
1047 void sctp_outq_free(struct sctp_outq*);
1048 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1049 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1050 int sctp_outq_is_empty(const struct sctp_outq *);
1051 void sctp_outq_restart(struct sctp_outq *);
1052 
1053 void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
1054 		     sctp_retransmit_reason_t);
1055 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1056 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1057 void sctp_prsctp_prune(struct sctp_association *asoc,
1058 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1059 /* Uncork and flush an outqueue.  */
1060 static inline void sctp_outq_cork(struct sctp_outq *q)
1061 {
1062 	q->cork = 1;
1063 }
1064 
1065 /* SCTP skb control block.
1066  * sctp_input_cb is currently used on rx and sock rx queue
1067  */
1068 struct sctp_input_cb {
1069 	union {
1070 		struct inet_skb_parm	h4;
1071 #if IS_ENABLED(CONFIG_IPV6)
1072 		struct inet6_skb_parm	h6;
1073 #endif
1074 	} header;
1075 	struct sctp_chunk *chunk;
1076 	struct sctp_af *af;
1077 };
1078 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1079 
1080 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1081 {
1082 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1083 
1084 	return chunk->head_skb ? : skb;
1085 }
1086 
1087 /* These bind address data fields common between endpoints and associations */
1088 struct sctp_bind_addr {
1089 
1090 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1091 	 *
1092 	 * SCTP Port:	The local SCTP port number the endpoint is
1093 	 *		bound to.
1094 	 */
1095 	__u16 port;
1096 
1097 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1098 	 *
1099 	 * Address List: The list of IP addresses that this instance
1100 	 *	has bound.  This information is passed to one's
1101 	 *	peer(s) in INIT and INIT ACK chunks.
1102 	 */
1103 	struct list_head address_list;
1104 };
1105 
1106 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1107 void sctp_bind_addr_free(struct sctp_bind_addr *);
1108 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1109 			const struct sctp_bind_addr *src,
1110 			sctp_scope_t scope, gfp_t gfp,
1111 			int flags);
1112 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1113 			const struct sctp_bind_addr *src,
1114 			gfp_t gfp);
1115 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1116 		       int new_size, __u8 addr_state, gfp_t gfp);
1117 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1118 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1119 			 struct sctp_sock *);
1120 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1121 			 struct sctp_sock *, struct sctp_sock *);
1122 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1123 			 const union sctp_addr *addr);
1124 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1125 					const union sctp_addr	*addrs,
1126 					int			addrcnt,
1127 					struct sctp_sock	*opt);
1128 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1129 					 int *addrs_len,
1130 					 gfp_t gfp);
1131 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1132 			   __u16 port, gfp_t gfp);
1133 
1134 sctp_scope_t sctp_scope(const union sctp_addr *);
1135 int sctp_in_scope(struct net *net, const union sctp_addr *addr, const sctp_scope_t scope);
1136 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1137 int sctp_is_ep_boundall(struct sock *sk);
1138 
1139 
1140 /* What type of endpoint?  */
1141 typedef enum {
1142 	SCTP_EP_TYPE_SOCKET,
1143 	SCTP_EP_TYPE_ASSOCIATION,
1144 } sctp_endpoint_type_t;
1145 
1146 /*
1147  * A common base class to bridge the implmentation view of a
1148  * socket (usually listening) endpoint versus an association's
1149  * local endpoint.
1150  * This common structure is useful for several purposes:
1151  *   1) Common interface for lookup routines.
1152  *	a) Subfunctions work for either endpoint or association
1153  *	b) Single interface to lookup allows hiding the lookup lock rather
1154  *	   than acquiring it externally.
1155  *   2) Common interface for the inbound chunk handling/state machine.
1156  *   3) Common object handling routines for reference counting, etc.
1157  *   4) Disentangle association lookup from endpoint lookup, where we
1158  *	do not have to find our endpoint to find our association.
1159  *
1160  */
1161 
1162 struct sctp_ep_common {
1163 	/* Fields to help us manage our entries in the hash tables. */
1164 	struct hlist_node node;
1165 	int hashent;
1166 
1167 	/* Runtime type information.  What kind of endpoint is this? */
1168 	sctp_endpoint_type_t type;
1169 
1170 	/* Some fields to help us manage this object.
1171 	 *   refcnt   - Reference count access to this object.
1172 	 *   dead     - Do not attempt to use this object.
1173 	 */
1174 	atomic_t    refcnt;
1175 	bool	    dead;
1176 
1177 	/* What socket does this endpoint belong to?  */
1178 	struct sock *sk;
1179 
1180 	/* This is where we receive inbound chunks.  */
1181 	struct sctp_inq	  inqueue;
1182 
1183 	/* This substructure includes the defining parameters of the
1184 	 * endpoint:
1185 	 * bind_addr.port is our shared port number.
1186 	 * bind_addr.address_list is our set of local IP addresses.
1187 	 */
1188 	struct sctp_bind_addr bind_addr;
1189 };
1190 
1191 
1192 /* RFC Section 1.4 Key Terms
1193  *
1194  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1195  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1196  *   combination of a set of eligible destination transport addresses to
1197  *   which SCTP packets can be sent and a set of eligible source
1198  *   transport addresses from which SCTP packets can be received.
1199  *   All transport addresses used by an SCTP endpoint must use the
1200  *   same port number, but can use multiple IP addresses. A transport
1201  *   address used by an SCTP endpoint must not be used by another
1202  *   SCTP endpoint. In other words, a transport address is unique
1203  *   to an SCTP endpoint.
1204  *
1205  * From an implementation perspective, each socket has one of these.
1206  * A TCP-style socket will have exactly one association on one of
1207  * these.  An UDP-style socket will have multiple associations hanging
1208  * off one of these.
1209  */
1210 
1211 struct sctp_endpoint {
1212 	/* Common substructure for endpoint and association. */
1213 	struct sctp_ep_common base;
1214 
1215 	/* Associations: A list of current associations and mappings
1216 	 *	      to the data consumers for each association. This
1217 	 *	      may be in the form of a hash table or other
1218 	 *	      implementation dependent structure. The data
1219 	 *	      consumers may be process identification
1220 	 *	      information such as file descriptors, named pipe
1221 	 *	      pointer, or table pointers dependent on how SCTP
1222 	 *	      is implemented.
1223 	 */
1224 	/* This is really a list of struct sctp_association entries. */
1225 	struct list_head asocs;
1226 
1227 	/* Secret Key: A secret key used by this endpoint to compute
1228 	 *	      the MAC.	This SHOULD be a cryptographic quality
1229 	 *	      random number with a sufficient length.
1230 	 *	      Discussion in [RFC1750] can be helpful in
1231 	 *	      selection of the key.
1232 	 */
1233 	__u8 secret_key[SCTP_SECRET_SIZE];
1234 
1235  	/* digest:  This is a digest of the sctp cookie.  This field is
1236  	 * 	    only used on the receive path when we try to validate
1237  	 * 	    that the cookie has not been tampered with.  We put
1238  	 * 	    this here so we pre-allocate this once and can re-use
1239  	 * 	    on every receive.
1240  	 */
1241  	__u8 *digest;
1242 
1243 	/* sendbuf acct. policy.	*/
1244 	__u32 sndbuf_policy;
1245 
1246 	/* rcvbuf acct. policy.	*/
1247 	__u32 rcvbuf_policy;
1248 
1249 	/* SCTP AUTH: array of the HMACs that will be allocated
1250 	 * we need this per association so that we don't serialize
1251 	 */
1252 	struct crypto_shash **auth_hmacs;
1253 
1254 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1255 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1256 
1257 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1258 	struct sctp_chunks_param *auth_chunk_list;
1259 
1260 	/* SCTP-AUTH: endpoint shared keys */
1261 	struct list_head endpoint_shared_keys;
1262 	__u16 active_key_id;
1263 	__u8  auth_enable:1,
1264 	      prsctp_enable:1,
1265 	      reconf_enable:1;
1266 
1267 	__u8  strreset_enable;
1268 };
1269 
1270 /* Recover the outter endpoint structure. */
1271 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1272 {
1273 	struct sctp_endpoint *ep;
1274 
1275 	ep = container_of(base, struct sctp_endpoint, base);
1276 	return ep;
1277 }
1278 
1279 /* These are function signatures for manipulating endpoints.  */
1280 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1281 void sctp_endpoint_free(struct sctp_endpoint *);
1282 void sctp_endpoint_put(struct sctp_endpoint *);
1283 void sctp_endpoint_hold(struct sctp_endpoint *);
1284 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1285 struct sctp_association *sctp_endpoint_lookup_assoc(
1286 	const struct sctp_endpoint *ep,
1287 	const union sctp_addr *paddr,
1288 	struct sctp_transport **);
1289 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1290 				const union sctp_addr *);
1291 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1292 					struct net *, const union sctp_addr *);
1293 int sctp_has_association(struct net *net, const union sctp_addr *laddr,
1294 			 const union sctp_addr *paddr);
1295 
1296 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1297 		     const struct sctp_association *asoc,
1298 		     sctp_cid_t, sctp_init_chunk_t *peer_init,
1299 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1300 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1301 		      const union sctp_addr *peer,
1302 		      sctp_init_chunk_t *init, gfp_t gfp);
1303 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1304 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1305 
1306 struct sctp_inithdr_host {
1307 	__u32 init_tag;
1308 	__u32 a_rwnd;
1309 	__u16 num_outbound_streams;
1310 	__u16 num_inbound_streams;
1311 	__u32 initial_tsn;
1312 };
1313 
1314 struct sctp_stream_out {
1315 	__u16	ssn;
1316 	__u8	state;
1317 };
1318 
1319 struct sctp_stream_in {
1320 	__u16	ssn;
1321 };
1322 
1323 struct sctp_stream {
1324 	struct sctp_stream_out *out;
1325 	struct sctp_stream_in *in;
1326 	__u16 outcnt;
1327 	__u16 incnt;
1328 };
1329 
1330 #define SCTP_STREAM_CLOSED		0x00
1331 #define SCTP_STREAM_OPEN		0x01
1332 
1333 /* SCTP_GET_ASSOC_STATS counters */
1334 struct sctp_priv_assoc_stats {
1335 	/* Maximum observed rto in the association during subsequent
1336 	 * observations. Value is set to 0 if no RTO measurement took place
1337 	 * The transport where the max_rto was observed is returned in
1338 	 * obs_rto_ipaddr
1339 	 */
1340 	struct sockaddr_storage obs_rto_ipaddr;
1341 	__u64 max_obs_rto;
1342 	/* Total In and Out SACKs received and sent */
1343 	__u64 isacks;
1344 	__u64 osacks;
1345 	/* Total In and Out packets received and sent */
1346 	__u64 opackets;
1347 	__u64 ipackets;
1348 	/* Total retransmitted chunks */
1349 	__u64 rtxchunks;
1350 	/* TSN received > next expected */
1351 	__u64 outofseqtsns;
1352 	/* Duplicate Chunks received */
1353 	__u64 idupchunks;
1354 	/* Gap Ack Blocks received */
1355 	__u64 gapcnt;
1356 	/* Unordered data chunks sent and received */
1357 	__u64 ouodchunks;
1358 	__u64 iuodchunks;
1359 	/* Ordered data chunks sent and received */
1360 	__u64 oodchunks;
1361 	__u64 iodchunks;
1362 	/* Control chunks sent and received */
1363 	__u64 octrlchunks;
1364 	__u64 ictrlchunks;
1365 };
1366 
1367 /* RFC2960
1368  *
1369  * 12. Recommended Transmission Control Block (TCB) Parameters
1370  *
1371  * This section details a recommended set of parameters that should
1372  * be contained within the TCB for an implementation. This section is
1373  * for illustrative purposes and should not be deemed as requirements
1374  * on an implementation or as an exhaustive list of all parameters
1375  * inside an SCTP TCB. Each implementation may need its own additional
1376  * parameters for optimization.
1377  */
1378 
1379 
1380 /* Here we have information about each individual association. */
1381 struct sctp_association {
1382 
1383 	/* A base structure common to endpoint and association.
1384 	 * In this context, it represents the associations's view
1385 	 * of the local endpoint of the association.
1386 	 */
1387 	struct sctp_ep_common base;
1388 
1389 	/* Associations on the same socket. */
1390 	struct list_head asocs;
1391 
1392 	/* association id. */
1393 	sctp_assoc_t assoc_id;
1394 
1395 	/* This is our parent endpoint.	 */
1396 	struct sctp_endpoint *ep;
1397 
1398 	/* These are those association elements needed in the cookie.  */
1399 	struct sctp_cookie c;
1400 
1401 	/* This is all information about our peer.  */
1402 	struct {
1403 		/* transport_addr_list
1404 		 *
1405 		 * Peer	       : A list of SCTP transport addresses that the
1406 		 * Transport   : peer is bound to. This information is derived
1407 		 * Address     : from the INIT or INIT ACK and is used to
1408 		 * List	       : associate an inbound packet with a given
1409 		 *	       : association. Normally this information is
1410 		 *	       : hashed or keyed for quick lookup and access
1411 		 *	       : of the TCB.
1412 		 *	       : The list is also initialized with the list
1413 		 *	       : of addresses passed with the sctp_connectx()
1414 		 *	       : call.
1415 		 *
1416 		 * It is a list of SCTP_transport's.
1417 		 */
1418 		struct list_head transport_addr_list;
1419 
1420 		/* rwnd
1421 		 *
1422 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1423 		 */
1424 		__u32 rwnd;
1425 
1426 		/* transport_count
1427 		 *
1428 		 * Peer        : A count of the number of peer addresses
1429 		 * Transport   : in the Peer Transport Address List.
1430 		 * Address     :
1431 		 * Count       :
1432 		 */
1433 		__u16 transport_count;
1434 
1435 		/* port
1436 		 *   The transport layer port number.
1437 		 */
1438 		__u16 port;
1439 
1440 		/* primary_path
1441 		 *
1442 		 * Primary     : This is the current primary destination
1443 		 * Path	       : transport address of the peer endpoint.  It
1444 		 *	       : may also specify a source transport address
1445 		 *	       : on this endpoint.
1446 		 *
1447 		 * All of these paths live on transport_addr_list.
1448 		 *
1449 		 * At the bakeoffs, we discovered that the intent of
1450 		 * primaryPath is that it only changes when the ULP
1451 		 * asks to have it changed.  We add the activePath to
1452 		 * designate the connection we are currently using to
1453 		 * transmit new data and most control chunks.
1454 		 */
1455 		struct sctp_transport *primary_path;
1456 
1457 		/* Cache the primary path address here, when we
1458 		 * need a an address for msg_name.
1459 		 */
1460 		union sctp_addr primary_addr;
1461 
1462 		/* active_path
1463 		 *   The path that we are currently using to
1464 		 *   transmit new data and most control chunks.
1465 		 */
1466 		struct sctp_transport *active_path;
1467 
1468 		/* retran_path
1469 		 *
1470 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1471 		 * ...
1472 		 * Furthermore, when its peer is multi-homed, an
1473 		 * endpoint SHOULD try to retransmit a chunk to an
1474 		 * active destination transport address that is
1475 		 * different from the last destination address to
1476 		 * which the DATA chunk was sent.
1477 		 */
1478 		struct sctp_transport *retran_path;
1479 
1480 		/* Pointer to last transport I have sent on.  */
1481 		struct sctp_transport *last_sent_to;
1482 
1483 		/* This is the last transport I have received DATA on.	*/
1484 		struct sctp_transport *last_data_from;
1485 
1486 		/*
1487 		 * Mapping  An array of bits or bytes indicating which out of
1488 		 * Array    order TSN's have been received (relative to the
1489 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1490 		 *	    order packets have been received, this array
1491 		 *	    will be set to all zero. This structure may be
1492 		 *	    in the form of a circular buffer or bit array.
1493 		 *
1494 		 * Last Rcvd   : This is the last TSN received in
1495 		 * TSN	       : sequence. This value is set initially by
1496 		 *	       : taking the peer's Initial TSN, received in
1497 		 *	       : the INIT or INIT ACK chunk, and subtracting
1498 		 *	       : one from it.
1499 		 *
1500 		 * Throughout most of the specification this is called the
1501 		 * "Cumulative TSN ACK Point".	In this case, we
1502 		 * ignore the advice in 12.2 in favour of the term
1503 		 * used in the bulk of the text.  This value is hidden
1504 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1505 		 */
1506 		struct sctp_tsnmap tsn_map;
1507 
1508 		/* This mask is used to disable sending the ASCONF chunk
1509 		 * with specified parameter to peer.
1510 		 */
1511 		__be16 addip_disabled_mask;
1512 
1513 		/* These are capabilities which our peer advertised.  */
1514 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1515 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1516 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1517 			hostname_address:1, /* Peer understands DNS addresses? */
1518 			asconf_capable:1,   /* Does peer support ADDIP? */
1519 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1520 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1521 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1522 
1523 		/* sack_needed : This flag indicates if the next received
1524 		 *             : packet is to be responded to with a
1525 		 *             : SACK. This is initialized to 0.  When a packet
1526 		 *             : is received sack_cnt is incremented. If this value
1527 		 *             : reaches 2 or more, a SACK is sent and the
1528 		 *             : value is reset to 0. Note: This is used only
1529 		 *             : when no DATA chunks are received out of
1530 		 *             : order.  When DATA chunks are out of order,
1531 		 *             : SACK's are not delayed (see Section 6).
1532 		 */
1533 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1534 			sack_generation:1,
1535 			zero_window_announced:1;
1536 		__u32	sack_cnt;
1537 
1538 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1539 
1540 		struct sctp_inithdr_host i;
1541 		void *cookie;
1542 		int cookie_len;
1543 
1544 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1545 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1546 		 * Initial TSN Value minus 1
1547 		 */
1548 		__u32 addip_serial;
1549 
1550 		/* SCTP-AUTH: We need to know pears random number, hmac list
1551 		 * and authenticated chunk list.  All that is part of the
1552 		 * cookie and these are just pointers to those locations
1553 		 */
1554 		sctp_random_param_t *peer_random;
1555 		sctp_chunks_param_t *peer_chunks;
1556 		sctp_hmac_algo_param_t *peer_hmacs;
1557 	} peer;
1558 
1559 	/* State       : A state variable indicating what state the
1560 	 *	       : association is in, i.e. COOKIE-WAIT,
1561 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1562 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1563 	 *
1564 	 *		Note: No "CLOSED" state is illustrated since if a
1565 	 *		association is "CLOSED" its TCB SHOULD be removed.
1566 	 *
1567 	 *		In this implementation we DO have a CLOSED
1568 	 *		state which is used during initiation and shutdown.
1569 	 *
1570 	 *		State takes values from SCTP_STATE_*.
1571 	 */
1572 	sctp_state_t state;
1573 
1574 	/* Overall     : The overall association error count.
1575 	 * Error Count : [Clear this any time I get something.]
1576 	 */
1577 	int overall_error_count;
1578 
1579 	/* The cookie life I award for any cookie.  */
1580 	ktime_t cookie_life;
1581 
1582 	/* These are the association's initial, max, and min RTO values.
1583 	 * These values will be initialized by system defaults, but can
1584 	 * be modified via the SCTP_RTOINFO socket option.
1585 	 */
1586 	unsigned long rto_initial;
1587 	unsigned long rto_max;
1588 	unsigned long rto_min;
1589 
1590 	/* Maximum number of new data packets that can be sent in a burst.  */
1591 	int max_burst;
1592 
1593 	/* This is the max_retrans value for the association.  This value will
1594 	 * be initialized initialized from system defaults, but can be
1595 	 * modified by the SCTP_ASSOCINFO socket option.
1596 	 */
1597 	int max_retrans;
1598 
1599 	/* This is the partially failed retrans value for the transport
1600 	 * and will be initialized from the assocs value.  This can be
1601 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1602 	 */
1603 	int pf_retrans;
1604 
1605 	/* Maximum number of times the endpoint will retransmit INIT  */
1606 	__u16 max_init_attempts;
1607 
1608 	/* How many times have we resent an INIT? */
1609 	__u16 init_retries;
1610 
1611 	/* The largest timeout or RTO value to use in attempting an INIT */
1612 	unsigned long max_init_timeo;
1613 
1614 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1615 	 * the destination address every heartbeat interval. This value
1616 	 * will be inherited by all new transports.
1617 	 */
1618 	unsigned long hbinterval;
1619 
1620 	/* This is the max_retrans value for new transports in the
1621 	 * association.
1622 	 */
1623 	__u16 pathmaxrxt;
1624 
1625 	/* Flag that path mtu update is pending */
1626 	__u8   pmtu_pending;
1627 
1628 	/* Association : The smallest PMTU discovered for all of the
1629 	 * PMTU	       : peer's transport addresses.
1630 	 */
1631 	__u32 pathmtu;
1632 
1633 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1634 	__u32 param_flags;
1635 
1636 	__u32 sackfreq;
1637 	/* SACK delay timeout */
1638 	unsigned long sackdelay;
1639 
1640 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1641 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1642 
1643 	/* Transport to which SHUTDOWN chunk was last sent.  */
1644 	struct sctp_transport *shutdown_last_sent_to;
1645 
1646 	/* Transport to which INIT chunk was last sent.  */
1647 	struct sctp_transport *init_last_sent_to;
1648 
1649 	/* How many times have we resent a SHUTDOWN */
1650 	int shutdown_retries;
1651 
1652 	/* Next TSN    : The next TSN number to be assigned to a new
1653 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1654 	 *	       : ACK chunk to the peer and incremented each
1655 	 *	       : time a DATA chunk is assigned a TSN
1656 	 *	       : (normally just prior to transmit or during
1657 	 *	       : fragmentation).
1658 	 */
1659 	__u32 next_tsn;
1660 
1661 	/*
1662 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1663 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1664 	 *	       : received in the INIT or INIT ACK chunk, and
1665 	 *	       : subtracting one from it.
1666 	 *
1667 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1668 	 */
1669 
1670 	__u32 ctsn_ack_point;
1671 
1672 	/* PR-SCTP Advanced.Peer.Ack.Point */
1673 	__u32 adv_peer_ack_point;
1674 
1675 	/* Highest TSN that is acknowledged by incoming SACKs. */
1676 	__u32 highest_sacked;
1677 
1678 	/* TSN marking the fast recovery exit point */
1679 	__u32 fast_recovery_exit;
1680 
1681 	/* Flag to track the current fast recovery state */
1682 	__u8 fast_recovery;
1683 
1684 	/* The number of unacknowledged data chunks.  Reported through
1685 	 * the SCTP_STATUS sockopt.
1686 	 */
1687 	__u16 unack_data;
1688 
1689 	/* The total number of data chunks that we've had to retransmit
1690 	 * as the result of a T3 timer expiration
1691 	 */
1692 	__u32 rtx_data_chunks;
1693 
1694 	/* This is the association's receive buffer space.  This value is used
1695 	 * to set a_rwnd field in an INIT or a SACK chunk.
1696 	 */
1697 	__u32 rwnd;
1698 
1699 	/* This is the last advertised value of rwnd over a SACK chunk. */
1700 	__u32 a_rwnd;
1701 
1702 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1703 	 * to slop over a maximum of the association's frag_point.
1704 	 */
1705 	__u32 rwnd_over;
1706 
1707 	/* Keeps treack of rwnd pressure.  This happens when we have
1708 	 * a window, but not recevie buffer (i.e small packets).  This one
1709 	 * is releases slowly (1 PMTU at a time ).
1710 	 */
1711 	__u32 rwnd_press;
1712 
1713 	/* This is the sndbuf size in use for the association.
1714 	 * This corresponds to the sndbuf size for the association,
1715 	 * as specified in the sk->sndbuf.
1716 	 */
1717 	int sndbuf_used;
1718 
1719 	/* This is the amount of memory that this association has allocated
1720 	 * in the receive path at any given time.
1721 	 */
1722 	atomic_t rmem_alloc;
1723 
1724 	/* This is the wait queue head for send requests waiting on
1725 	 * the association sndbuf space.
1726 	 */
1727 	wait_queue_head_t	wait;
1728 
1729 	/* The message size at which SCTP fragmentation will occur. */
1730 	__u32 frag_point;
1731 	__u32 user_frag;
1732 
1733 	/* Counter used to count INIT errors. */
1734 	int init_err_counter;
1735 
1736 	/* Count the number of INIT cycles (for doubling timeout). */
1737 	int init_cycle;
1738 
1739 	/* Default send parameters. */
1740 	__u16 default_stream;
1741 	__u16 default_flags;
1742 	__u32 default_ppid;
1743 	__u32 default_context;
1744 	__u32 default_timetolive;
1745 
1746 	/* Default receive parameters */
1747 	__u32 default_rcv_context;
1748 
1749 	/* Stream arrays */
1750 	struct sctp_stream *stream;
1751 
1752 	/* All outbound chunks go through this structure.  */
1753 	struct sctp_outq outqueue;
1754 
1755 	/* A smart pipe that will handle reordering and fragmentation,
1756 	 * as well as handle passing events up to the ULP.
1757 	 */
1758 	struct sctp_ulpq ulpq;
1759 
1760 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1761 	__u32 last_ecne_tsn;
1762 
1763 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1764 	__u32 last_cwr_tsn;
1765 
1766 	/* How many duplicated TSNs have we seen?  */
1767 	int numduptsns;
1768 
1769 	/* These are to support
1770 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1771 	 *  and Enforcement of Flow and Message Limits"
1772 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1773 	 * or "ADDIP" for short.
1774 	 */
1775 
1776 
1777 
1778 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1779 	 *
1780 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1781 	 * unacknowledged at any one time.  If a sender, after sending
1782 	 * an ASCONF chunk, decides it needs to transfer another
1783 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1784 	 * returns from the previous ASCONF Chunk before sending a
1785 	 * subsequent ASCONF. Note this restriction binds each side,
1786 	 * so at any time two ASCONF may be in-transit on any given
1787 	 * association (one sent from each endpoint).
1788 	 *
1789 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1790 	 * not have an ASCONF in flight, this is NULL.]
1791 	 */
1792 	struct sctp_chunk *addip_last_asconf;
1793 
1794 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1795 	 *
1796 	 * This is needed to implement itmes E1 - E4 of the updated
1797 	 * spec.  Here is the justification:
1798 	 *
1799 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1800 	 * we now need the ability to cache multiple ACKs.  The section
1801 	 * describes in detail how they are cached and cleaned up.
1802 	 */
1803 	struct list_head asconf_ack_list;
1804 
1805 	/* These ASCONF chunks are waiting to be sent.
1806 	 *
1807 	 * These chunaks can't be pushed to outqueue until receiving
1808 	 * ASCONF_ACK for the previous ASCONF indicated by
1809 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1810 	 * is in flight at any time.
1811 	 *
1812 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1813 	 *
1814 	 * In defining the ASCONF Chunk transfer procedures, it is
1815 	 * essential that these transfers MUST NOT cause congestion
1816 	 * within the network.	To achieve this, we place these
1817 	 * restrictions on the transfer of ASCONF Chunks:
1818 	 *
1819 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1820 	 * unacknowledged at any one time.  If a sender, after sending
1821 	 * an ASCONF chunk, decides it needs to transfer another
1822 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1823 	 * returns from the previous ASCONF Chunk before sending a
1824 	 * subsequent ASCONF. Note this restriction binds each side,
1825 	 * so at any time two ASCONF may be in-transit on any given
1826 	 * association (one sent from each endpoint).
1827 	 *
1828 	 *
1829 	 * [I really think this is EXACTLY the sort of intelligence
1830 	 *  which already resides in sctp_outq.	 Please move this
1831 	 *  queue and its supporting logic down there.	--piggy]
1832 	 */
1833 	struct list_head addip_chunk_list;
1834 
1835 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1836 	 *
1837 	 * A2) A serial number should be assigned to the Chunk. The
1838 	 * serial number SHOULD be a monotonically increasing
1839 	 * number. The serial number SHOULD be initialized at
1840 	 * the start of the association to the same value as the
1841 	 * Initial TSN and every time a new ASCONF chunk is created
1842 	 * it is incremented by one after assigning the serial number
1843 	 * to the newly created chunk.
1844 	 *
1845 	 * ADDIP
1846 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1847 	 *
1848 	 * Serial Number : 32 bits (unsigned integer)
1849 	 *
1850 	 * This value represents a Serial Number for the ASCONF
1851 	 * Chunk. The valid range of Serial Number is from 0 to
1852 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1853 	 * after reaching 4294967295.
1854 	 */
1855 	__u32 addip_serial;
1856 	int src_out_of_asoc_ok;
1857 	union sctp_addr *asconf_addr_del_pending;
1858 	struct sctp_transport *new_transport;
1859 
1860 	/* SCTP AUTH: list of the endpoint shared keys.  These
1861 	 * keys are provided out of band by the user applicaton
1862 	 * and can't change during the lifetime of the association
1863 	 */
1864 	struct list_head endpoint_shared_keys;
1865 
1866 	/* SCTP AUTH:
1867 	 * The current generated assocaition shared key (secret)
1868 	 */
1869 	struct sctp_auth_bytes *asoc_shared_key;
1870 
1871 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1872 	 * that we support.
1873 	 */
1874 	__u16 default_hmac_id;
1875 
1876 	__u16 active_key_id;
1877 
1878 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
1879 	     temp:1,		/* Is it a temporary association? */
1880 	     prsctp_enable:1,
1881 	     reconf_enable:1;
1882 
1883 	__u8 strreset_enable;
1884 	__u8 strreset_outstanding; /* request param count on the fly */
1885 
1886 	__u32 strreset_outseq; /* Update after receiving response */
1887 	__u32 strreset_inseq; /* Update after receiving request */
1888 
1889 	struct sctp_chunk *strreset_chunk; /* save request chunk */
1890 
1891 	struct sctp_priv_assoc_stats stats;
1892 
1893 	int sent_cnt_removable;
1894 
1895 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1896 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1897 };
1898 
1899 
1900 /* An eyecatcher for determining if we are really looking at an
1901  * association data structure.
1902  */
1903 enum {
1904 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1905 };
1906 
1907 /* Recover the outter association structure. */
1908 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1909 {
1910 	struct sctp_association *asoc;
1911 
1912 	asoc = container_of(base, struct sctp_association, base);
1913 	return asoc;
1914 }
1915 
1916 /* These are function signatures for manipulating associations.	 */
1917 
1918 
1919 struct sctp_association *
1920 sctp_association_new(const struct sctp_endpoint *, const struct sock *,
1921 		     sctp_scope_t scope, gfp_t gfp);
1922 void sctp_association_free(struct sctp_association *);
1923 void sctp_association_put(struct sctp_association *);
1924 void sctp_association_hold(struct sctp_association *);
1925 
1926 struct sctp_transport *sctp_assoc_choose_alter_transport(
1927 	struct sctp_association *, struct sctp_transport *);
1928 void sctp_assoc_update_retran_path(struct sctp_association *);
1929 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1930 					  const union sctp_addr *);
1931 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1932 			    const union sctp_addr *laddr);
1933 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
1934 				     const union sctp_addr *address,
1935 				     const gfp_t gfp,
1936 				     const int peer_state);
1937 void sctp_assoc_del_peer(struct sctp_association *asoc,
1938 			 const union sctp_addr *addr);
1939 void sctp_assoc_rm_peer(struct sctp_association *asoc,
1940 			 struct sctp_transport *peer);
1941 void sctp_assoc_control_transport(struct sctp_association *,
1942 				  struct sctp_transport *,
1943 				  sctp_transport_cmd_t, sctp_sn_error_t);
1944 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
1945 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
1946 					   struct net *,
1947 					   const union sctp_addr *,
1948 					   const union sctp_addr *);
1949 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
1950 void sctp_assoc_update(struct sctp_association *old,
1951 		       struct sctp_association *new);
1952 
1953 __u32 sctp_association_get_next_tsn(struct sctp_association *);
1954 
1955 void sctp_assoc_sync_pmtu(struct sock *, struct sctp_association *);
1956 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
1957 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
1958 void sctp_assoc_set_primary(struct sctp_association *,
1959 			    struct sctp_transport *);
1960 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
1961 				    struct sctp_transport *);
1962 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
1963 				     sctp_scope_t, gfp_t);
1964 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
1965 					 struct sctp_cookie*,
1966 					 gfp_t gfp);
1967 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
1968 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
1969 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1970 					const struct sctp_association *asoc,
1971 					__be32 serial);
1972 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
1973 
1974 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
1975 			const union sctp_addr *ss2);
1976 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
1977 
1978 /* A convenience structure to parse out SCTP specific CMSGs. */
1979 typedef struct sctp_cmsgs {
1980 	struct sctp_initmsg *init;
1981 	struct sctp_sndrcvinfo *srinfo;
1982 	struct sctp_sndinfo *sinfo;
1983 } sctp_cmsgs_t;
1984 
1985 /* Structure for tracking memory objects */
1986 typedef struct {
1987 	char *label;
1988 	atomic_t *counter;
1989 } sctp_dbg_objcnt_entry_t;
1990 
1991 #endif /* __sctp_structs_h__ */
1992