xref: /linux/include/net/sctp/structs.h (revision 4246b92cf9fb32da8d8b060c92d8302797c6fbea)
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 struct sctp_stream;
87 
88 
89 #include <net/sctp/tsnmap.h>
90 #include <net/sctp/ulpevent.h>
91 #include <net/sctp/ulpqueue.h>
92 
93 /* Structures useful for managing bind/connect. */
94 
95 struct sctp_bind_bucket {
96 	unsigned short	port;
97 	unsigned short	fastreuse;
98 	struct hlist_node	node;
99 	struct hlist_head	owner;
100 	struct net	*net;
101 };
102 
103 struct sctp_bind_hashbucket {
104 	spinlock_t	lock;
105 	struct hlist_head	chain;
106 };
107 
108 /* Used for hashing all associations.  */
109 struct sctp_hashbucket {
110 	rwlock_t	lock;
111 	struct hlist_head	chain;
112 } __attribute__((__aligned__(8)));
113 
114 
115 /* The SCTP globals structure. */
116 extern struct sctp_globals {
117 	/* This is a list of groups of functions for each address
118 	 * family that we support.
119 	 */
120 	struct list_head address_families;
121 
122 	/* This is the hash of all endpoints. */
123 	struct sctp_hashbucket *ep_hashtable;
124 	/* This is the sctp port control hash.	*/
125 	struct sctp_bind_hashbucket *port_hashtable;
126 	/* This is the hash of all transports. */
127 	struct rhltable transport_hashtable;
128 
129 	/* Sizes of above hashtables. */
130 	int ep_hashsize;
131 	int port_hashsize;
132 
133 	/* Default initialization values to be applied to new associations. */
134 	__u16 max_instreams;
135 	__u16 max_outstreams;
136 
137 	/* Flag to indicate whether computing and verifying checksum
138 	 * is disabled. */
139         bool checksum_disable;
140 } sctp_globals;
141 
142 #define sctp_max_instreams		(sctp_globals.max_instreams)
143 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
144 #define sctp_address_families		(sctp_globals.address_families)
145 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
146 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
147 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
148 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
149 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
150 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
151 
152 /* SCTP Socket type: UDP or TCP style. */
153 enum sctp_socket_type {
154 	SCTP_SOCKET_UDP = 0,
155 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
156 	SCTP_SOCKET_TCP
157 };
158 
159 /* Per socket SCTP information. */
160 struct sctp_sock {
161 	/* inet_sock has to be the first member of sctp_sock */
162 	struct inet_sock inet;
163 	/* What kind of a socket is this? */
164 	enum sctp_socket_type type;
165 
166 	/* PF_ family specific functions.  */
167 	struct sctp_pf *pf;
168 
169 	/* Access to HMAC transform. */
170 	struct crypto_shash *hmac;
171 	char *sctp_hmac_alg;
172 
173 	/* What is our base endpointer? */
174 	struct sctp_endpoint *ep;
175 
176 	struct sctp_bind_bucket *bind_hash;
177 	/* Various Socket Options.  */
178 	__u16 default_stream;
179 	__u32 default_ppid;
180 	__u16 default_flags;
181 	__u32 default_context;
182 	__u32 default_timetolive;
183 	__u32 default_rcv_context;
184 	int max_burst;
185 
186 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
187 	 * the destination address every heartbeat interval. This value
188 	 * will be inherited by all new associations.
189 	 */
190 	__u32 hbinterval;
191 
192 	/* This is the max_retrans value for new associations. */
193 	__u16 pathmaxrxt;
194 
195 	/* The initial Path MTU to use for new associations. */
196 	__u32 pathmtu;
197 
198 	/* The default SACK delay timeout for new associations. */
199 	__u32 sackdelay;
200 	__u32 sackfreq;
201 
202 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
203 	__u32 param_flags;
204 
205 	struct sctp_initmsg initmsg;
206 	struct sctp_rtoinfo rtoinfo;
207 	struct sctp_paddrparams paddrparam;
208 	struct sctp_event_subscribe subscribe;
209 	struct sctp_assocparams assocparams;
210 
211 	int user_frag;
212 
213 	__u32 autoclose;
214 	__u32 adaptation_ind;
215 	__u32 pd_point;
216 	__u16	nodelay:1,
217 		disable_fragments:1,
218 		v4mapped:1,
219 		frag_interleave:1,
220 		recvrcvinfo:1,
221 		recvnxtinfo:1,
222 		data_ready_signalled:1;
223 
224 	atomic_t pd_mode;
225 	/* Receive to here while partial delivery is in effect. */
226 	struct sk_buff_head pd_lobby;
227 
228 	/* These must be the last fields, as they will skipped on copies,
229 	 * like on accept and peeloff operations
230 	 */
231 	struct list_head auto_asconf_list;
232 	int do_auto_asconf;
233 };
234 
235 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
236 {
237        return (struct sctp_sock *)sk;
238 }
239 
240 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
241 {
242        return (struct sock *)sp;
243 }
244 
245 #if IS_ENABLED(CONFIG_IPV6)
246 struct sctp6_sock {
247        struct sctp_sock  sctp;
248        struct ipv6_pinfo inet6;
249 };
250 #endif /* CONFIG_IPV6 */
251 
252 
253 /* This is our APPLICATION-SPECIFIC state cookie.
254  * THIS IS NOT DICTATED BY THE SPECIFICATION.
255  */
256 /* These are the parts of an association which we send in the cookie.
257  * Most of these are straight out of:
258  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
259  *
260  */
261 
262 struct sctp_cookie {
263 
264 	/* My	       : Tag expected in every inbound packet and sent
265 	 * Verification: in the INIT or INIT ACK chunk.
266 	 * Tag	       :
267 	 */
268 	__u32 my_vtag;
269 
270 	/* Peer's      : Tag expected in every outbound packet except
271 	 * Verification: in the INIT chunk.
272 	 * Tag	       :
273 	 */
274 	__u32 peer_vtag;
275 
276 	/* The rest of these are not from the spec, but really need to
277 	 * be in the cookie.
278 	 */
279 
280 	/* My Tie Tag  : Assist in discovering a restarting association. */
281 	__u32 my_ttag;
282 
283 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
284 	__u32 peer_ttag;
285 
286 	/* When does this cookie expire? */
287 	ktime_t expiration;
288 
289 	/* Number of inbound/outbound streams which are set
290 	 * and negotiated during the INIT process.
291 	 */
292 	__u16 sinit_num_ostreams;
293 	__u16 sinit_max_instreams;
294 
295 	/* This is the first sequence number I used.  */
296 	__u32 initial_tsn;
297 
298 	/* This holds the originating address of the INIT packet.  */
299 	union sctp_addr peer_addr;
300 
301 	/* IG Section 2.35.3
302 	 * Include the source port of the INIT-ACK
303 	 */
304 	__u16		my_port;
305 
306 	__u8 prsctp_capable;
307 
308 	/* Padding for future use */
309 	__u8 padding;
310 
311 	__u32 adaptation_ind;
312 
313 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
314 			 SCTP_AUTH_RANDOM_LENGTH];
315 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
316 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
317 
318 	/* This is a shim for my peer's INIT packet, followed by
319 	 * a copy of the raw address list of the association.
320 	 * The length of the raw address list is saved in the
321 	 * raw_addr_list_len field, which will be used at the time when
322 	 * the association TCB is re-constructed from the cookie.
323 	 */
324 	__u32 raw_addr_list_len;
325 	struct sctp_init_chunk peer_init[0];
326 };
327 
328 
329 /* The format of our cookie that we send to our peer. */
330 struct sctp_signed_cookie {
331 	__u8 signature[SCTP_SECRET_SIZE];
332 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
333 	struct sctp_cookie c;
334 } __packed;
335 
336 /* This is another convenience type to allocate memory for address
337  * params for the maximum size and pass such structures around
338  * internally.
339  */
340 union sctp_addr_param {
341 	struct sctp_paramhdr p;
342 	struct sctp_ipv4addr_param v4;
343 	struct sctp_ipv6addr_param v6;
344 };
345 
346 /* A convenience type to allow walking through the various
347  * parameters and avoid casting all over the place.
348  */
349 union sctp_params {
350 	void *v;
351 	struct sctp_paramhdr *p;
352 	struct sctp_cookie_preserve_param *life;
353 	struct sctp_hostname_param *dns;
354 	struct sctp_cookie_param *cookie;
355 	struct sctp_supported_addrs_param *sat;
356 	struct sctp_ipv4addr_param *v4;
357 	struct sctp_ipv6addr_param *v6;
358 	union sctp_addr_param *addr;
359 	struct sctp_adaptation_ind_param *aind;
360 	struct sctp_supported_ext_param *ext;
361 	struct sctp_random_param *random;
362 	struct sctp_chunks_param *chunks;
363 	struct sctp_hmac_algo_param *hmac_algo;
364 	struct sctp_addip_param *addip;
365 };
366 
367 /* RFC 2960.  Section 3.3.5 Heartbeat.
368  *    Heartbeat Information: variable length
369  *    The Sender-specific Heartbeat Info field should normally include
370  *    information about the sender's current time when this HEARTBEAT
371  *    chunk is sent and the destination transport address to which this
372  *    HEARTBEAT is sent (see Section 8.3).
373  */
374 struct sctp_sender_hb_info {
375 	struct sctp_paramhdr param_hdr;
376 	union sctp_addr daddr;
377 	unsigned long sent_at;
378 	__u64 hb_nonce;
379 };
380 
381 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
382 		     gfp_t gfp);
383 void sctp_stream_free(struct sctp_stream *stream);
384 void sctp_stream_clear(struct sctp_stream *stream);
385 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
386 
387 /* What is the current SSN number for this stream? */
388 #define sctp_ssn_peek(stream, type, sid) \
389 	((stream)->type[sid].ssn)
390 
391 /* Return the next SSN number for this stream.	*/
392 #define sctp_ssn_next(stream, type, sid) \
393 	((stream)->type[sid].ssn++)
394 
395 /* Skip over this ssn and all below. */
396 #define sctp_ssn_skip(stream, type, sid, ssn) \
397 	((stream)->type[sid].ssn = ssn + 1)
398 
399 /*
400  * Pointers to address related SCTP functions.
401  * (i.e. things that depend on the address family.)
402  */
403 struct sctp_af {
404 	int		(*sctp_xmit)	(struct sk_buff *skb,
405 					 struct sctp_transport *);
406 	int		(*setsockopt)	(struct sock *sk,
407 					 int level,
408 					 int optname,
409 					 char __user *optval,
410 					 unsigned int optlen);
411 	int		(*getsockopt)	(struct sock *sk,
412 					 int level,
413 					 int optname,
414 					 char __user *optval,
415 					 int __user *optlen);
416 	int		(*compat_setsockopt)	(struct sock *sk,
417 					 int level,
418 					 int optname,
419 					 char __user *optval,
420 					 unsigned int optlen);
421 	int		(*compat_getsockopt)	(struct sock *sk,
422 					 int level,
423 					 int optname,
424 					 char __user *optval,
425 					 int __user *optlen);
426 	void		(*get_dst)	(struct sctp_transport *t,
427 					 union sctp_addr *saddr,
428 					 struct flowi *fl,
429 					 struct sock *sk);
430 	void		(*get_saddr)	(struct sctp_sock *sk,
431 					 struct sctp_transport *t,
432 					 struct flowi *fl);
433 	void		(*copy_addrlist) (struct list_head *,
434 					  struct net_device *);
435 	int		(*cmp_addr)	(const union sctp_addr *addr1,
436 					 const union sctp_addr *addr2);
437 	void		(*addr_copy)	(union sctp_addr *dst,
438 					 union sctp_addr *src);
439 	void		(*from_skb)	(union sctp_addr *,
440 					 struct sk_buff *skb,
441 					 int saddr);
442 	void		(*from_sk)	(union sctp_addr *,
443 					 struct sock *sk);
444 	void		(*from_addr_param) (union sctp_addr *,
445 					    union sctp_addr_param *,
446 					    __be16 port, int iif);
447 	int		(*to_addr_param) (const union sctp_addr *,
448 					  union sctp_addr_param *);
449 	int		(*addr_valid)	(union sctp_addr *,
450 					 struct sctp_sock *,
451 					 const struct sk_buff *);
452 	enum sctp_scope	(*scope)(union sctp_addr *);
453 	void		(*inaddr_any)	(union sctp_addr *, __be16);
454 	int		(*is_any)	(const union sctp_addr *);
455 	int		(*available)	(union sctp_addr *,
456 					 struct sctp_sock *);
457 	int		(*skb_iif)	(const struct sk_buff *sk);
458 	int		(*is_ce)	(const struct sk_buff *sk);
459 	void		(*seq_dump_addr)(struct seq_file *seq,
460 					 union sctp_addr *addr);
461 	void		(*ecn_capable)(struct sock *sk);
462 	__u16		net_header_len;
463 	int		sockaddr_len;
464 	sa_family_t	sa_family;
465 	struct list_head list;
466 };
467 
468 struct sctp_af *sctp_get_af_specific(sa_family_t);
469 int sctp_register_af(struct sctp_af *);
470 
471 /* Protocol family functions. */
472 struct sctp_pf {
473 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
474 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
475 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
476 	int  (*cmp_addr) (const union sctp_addr *,
477 			  const union sctp_addr *,
478 			  struct sctp_sock *);
479 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
480 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
481 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
482 	struct sock *(*create_accept_sk) (struct sock *sk,
483 					  struct sctp_association *asoc,
484 					  bool kern);
485 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
486 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
487 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
488 	struct sctp_af *af;
489 };
490 
491 
492 /* Structure to track chunk fragments that have been acked, but peer
493  * fragments of the same message have not.
494  */
495 struct sctp_datamsg {
496 	/* Chunks waiting to be submitted to lower layer. */
497 	struct list_head chunks;
498 	/* Reference counting. */
499 	refcount_t refcnt;
500 	/* When is this message no longer interesting to the peer? */
501 	unsigned long expires_at;
502 	/* Did the messenge fail to send? */
503 	int send_error;
504 	u8 send_failed:1,
505 	   can_delay;	    /* should this message be Nagle delayed */
506 };
507 
508 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
509 					    struct sctp_sndrcvinfo *,
510 					    struct iov_iter *);
511 void sctp_datamsg_free(struct sctp_datamsg *);
512 void sctp_datamsg_put(struct sctp_datamsg *);
513 void sctp_chunk_fail(struct sctp_chunk *, int error);
514 int sctp_chunk_abandoned(struct sctp_chunk *);
515 
516 /* RFC2960 1.4 Key Terms
517  *
518  * o Chunk: A unit of information within an SCTP packet, consisting of
519  * a chunk header and chunk-specific content.
520  *
521  * As a matter of convenience, we remember the SCTP common header for
522  * each chunk as well as a few other header pointers...
523  */
524 struct sctp_chunk {
525 	struct list_head list;
526 
527 	refcount_t refcnt;
528 
529 	/* How many times this chunk have been sent, for prsctp RTX policy */
530 	int sent_count;
531 
532 	/* This is our link to the per-transport transmitted list.  */
533 	struct list_head transmitted_list;
534 
535 	/* This field is used by chunks that hold fragmented data.
536 	 * For the first fragment this is the list that holds the rest of
537 	 * fragments. For the remaining fragments, this is the link to the
538 	 * frag_list maintained in the first fragment.
539 	 */
540 	struct list_head frag_list;
541 
542 	/* This points to the sk_buff containing the actual data.  */
543 	struct sk_buff *skb;
544 
545 	/* In case of GSO packets, this will store the head one */
546 	struct sk_buff *head_skb;
547 
548 	/* These are the SCTP headers by reverse order in a packet.
549 	 * Note that some of these may happen more than once.  In that
550 	 * case, we point at the "current" one, whatever that means
551 	 * for that level of header.
552 	 */
553 
554 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
555 	union sctp_params param_hdr;
556 	union {
557 		__u8 *v;
558 		struct sctp_datahdr *data_hdr;
559 		struct sctp_inithdr *init_hdr;
560 		struct sctp_sackhdr *sack_hdr;
561 		struct sctp_heartbeathdr *hb_hdr;
562 		struct sctp_sender_hb_info *hbs_hdr;
563 		struct sctp_shutdownhdr *shutdown_hdr;
564 		struct sctp_signed_cookie *cookie_hdr;
565 		struct sctp_ecnehdr *ecne_hdr;
566 		struct sctp_cwrhdr *ecn_cwr_hdr;
567 		struct sctp_errhdr *err_hdr;
568 		struct sctp_addiphdr *addip_hdr;
569 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
570 		struct sctp_authhdr *auth_hdr;
571 	} subh;
572 
573 	__u8 *chunk_end;
574 
575 	struct sctp_chunkhdr *chunk_hdr;
576 	struct sctphdr *sctp_hdr;
577 
578 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
579 	struct sctp_sndrcvinfo sinfo;
580 
581 	/* Which association does this belong to?  */
582 	struct sctp_association *asoc;
583 
584 	/* What endpoint received this chunk? */
585 	struct sctp_ep_common *rcvr;
586 
587 	/* We fill this in if we are calculating RTT. */
588 	unsigned long sent_at;
589 
590 	/* What is the origin IP address for this chunk?  */
591 	union sctp_addr source;
592 	/* Destination address for this chunk. */
593 	union sctp_addr dest;
594 
595 	/* For outbound message, track all fragments for SEND_FAILED. */
596 	struct sctp_datamsg *msg;
597 
598 	/* For an inbound chunk, this tells us where it came from.
599 	 * For an outbound chunk, it tells us where we'd like it to
600 	 * go.	It is NULL if we have no preference.
601 	 */
602 	struct sctp_transport *transport;
603 
604 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
605 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
606 	 * spec violates the principle premis that all chunks are processed
607 	 * in order.
608 	 */
609 	struct sk_buff *auth_chunk;
610 
611 #define SCTP_CAN_FRTX 0x0
612 #define SCTP_NEED_FRTX 0x1
613 #define SCTP_DONT_FRTX 0x2
614 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
615 		has_tsn:1,		/* Does this chunk have a TSN yet? */
616 		has_ssn:1,		/* Does this chunk have a SSN yet? */
617 		singleton:1,		/* Only chunk in the packet? */
618 		end_of_packet:1,	/* Last chunk in the packet? */
619 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
620 		pdiscard:1,		/* Discard the whole packet now? */
621 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
622 		data_accepted:1,	/* At least 1 chunk accepted */
623 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
624 		has_asconf:1,		/* IN: have seen an asconf before */
625 		tsn_missing_report:2,	/* Data chunk missing counter. */
626 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
627 };
628 
629 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
630 void sctp_chunk_hold(struct sctp_chunk *);
631 void sctp_chunk_put(struct sctp_chunk *);
632 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
633 			  struct iov_iter *from);
634 void sctp_chunk_free(struct sctp_chunk *);
635 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
636 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
637 				 const struct sctp_association *,
638 				 struct sock *, gfp_t gfp);
639 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
640 		     union sctp_addr *);
641 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
642 
643 enum {
644 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
645 	SCTP_ADDR_SRC,		/* address can be used as source */
646 	SCTP_ADDR_DEL,		/* address about to be deleted */
647 };
648 
649 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
650 struct sctp_sockaddr_entry {
651 	struct list_head list;
652 	struct rcu_head	rcu;
653 	union sctp_addr a;
654 	__u8 state;
655 	__u8 valid;
656 };
657 
658 #define SCTP_ADDRESS_TICK_DELAY	500
659 
660 /* This structure holds lists of chunks as we are assembling for
661  * transmission.
662  */
663 struct sctp_packet {
664 	/* These are the SCTP header values (host order) for the packet. */
665 	__u16 source_port;
666 	__u16 destination_port;
667 	__u32 vtag;
668 
669 	/* This contains the payload chunks.  */
670 	struct list_head chunk_list;
671 
672 	/* This is the overhead of the sctp and ip headers. */
673 	size_t overhead;
674 	/* This is the total size of all chunks INCLUDING padding.  */
675 	size_t size;
676 	/* This is the maximum size this packet may have */
677 	size_t max_size;
678 
679 	/* The packet is destined for this transport address.
680 	 * The function we finally use to pass down to the next lower
681 	 * layer lives in the transport structure.
682 	 */
683 	struct sctp_transport *transport;
684 
685 	/* pointer to the auth chunk for this packet */
686 	struct sctp_chunk *auth;
687 
688 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
689 	    has_sack:1,		/* This packet contains a SACK chunk. */
690 	    has_auth:1,		/* This packet contains an AUTH chunk */
691 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
692 	    ipfragok:1;		/* So let ip fragment this packet */
693 };
694 
695 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
696 		      __u16 sport, __u16 dport);
697 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
698 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
699 					  struct sctp_chunk *chunk,
700 					  int one_packet, gfp_t gfp);
701 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
702 					struct sctp_chunk *chunk);
703 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
704 void sctp_packet_free(struct sctp_packet *);
705 
706 static inline int sctp_packet_empty(struct sctp_packet *packet)
707 {
708 	return packet->size == packet->overhead;
709 }
710 
711 /* This represents a remote transport address.
712  * For local transport addresses, we just use union sctp_addr.
713  *
714  * RFC2960 Section 1.4 Key Terms
715  *
716  *   o	Transport address:  A Transport Address is traditionally defined
717  *	by Network Layer address, Transport Layer protocol and Transport
718  *	Layer port number.  In the case of SCTP running over IP, a
719  *	transport address is defined by the combination of an IP address
720  *	and an SCTP port number (where SCTP is the Transport protocol).
721  *
722  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
723  *
724  *   o	The sender keeps a separate congestion control parameter set for
725  *	each of the destination addresses it can send to (not each
726  *	source-destination pair but for each destination).  The parameters
727  *	should decay if the address is not used for a long enough time
728  *	period.
729  *
730  */
731 struct sctp_transport {
732 	/* A list of transports. */
733 	struct list_head transports;
734 	struct rhlist_head node;
735 
736 	/* Reference counting. */
737 	refcount_t refcnt;
738 		/* RTO-Pending : A flag used to track if one of the DATA
739 		 *		chunks sent to this address is currently being
740 		 *		used to compute a RTT. If this flag is 0,
741 		 *		the next DATA chunk sent to this destination
742 		 *		should be used to compute a RTT and this flag
743 		 *		should be set. Every time the RTT
744 		 *		calculation completes (i.e. the DATA chunk
745 		 *		is SACK'd) clear this flag.
746 		 */
747 	__u32	rto_pending:1,
748 
749 		/*
750 		 * hb_sent : a flag that signals that we have a pending
751 		 * heartbeat.
752 		 */
753 		hb_sent:1,
754 
755 		/* Is the Path MTU update pending on this tranport */
756 		pmtu_pending:1,
757 
758 		dst_pending_confirm:1,	/* need to confirm neighbour */
759 
760 		/* Has this transport moved the ctsn since we last sacked */
761 		sack_generation:1;
762 	u32 dst_cookie;
763 
764 	struct flowi fl;
765 
766 	/* This is the peer's IP address and port. */
767 	union sctp_addr ipaddr;
768 
769 	/* These are the functions we call to handle LLP stuff.	 */
770 	struct sctp_af *af_specific;
771 
772 	/* Which association do we belong to?  */
773 	struct sctp_association *asoc;
774 
775 	/* RFC2960
776 	 *
777 	 * 12.3 Per Transport Address Data
778 	 *
779 	 * For each destination transport address in the peer's
780 	 * address list derived from the INIT or INIT ACK chunk, a
781 	 * number of data elements needs to be maintained including:
782 	 */
783 	/* RTO	       : The current retransmission timeout value.  */
784 	unsigned long rto;
785 
786 	__u32 rtt;		/* This is the most recent RTT.	 */
787 
788 	/* RTTVAR      : The current RTT variation.  */
789 	__u32 rttvar;
790 
791 	/* SRTT	       : The current smoothed round trip time.	*/
792 	__u32 srtt;
793 
794 	/*
795 	 * These are the congestion stats.
796 	 */
797 	/* cwnd	       : The current congestion window.	 */
798 	__u32 cwnd;		  /* This is the actual cwnd.  */
799 
800 	/* ssthresh    : The current slow start threshold value.  */
801 	__u32 ssthresh;
802 
803 	/* partial     : The tracking method for increase of cwnd when in
804 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
805 	 */
806 	__u32 partial_bytes_acked;
807 
808 	/* Data that has been sent, but not acknowledged. */
809 	__u32 flight_size;
810 
811 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
812 
813 	/* Destination */
814 	struct dst_entry *dst;
815 	/* Source address. */
816 	union sctp_addr saddr;
817 
818 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
819 	 * the destination address every heartbeat interval.
820 	 */
821 	unsigned long hbinterval;
822 
823 	/* SACK delay timeout */
824 	unsigned long sackdelay;
825 	__u32 sackfreq;
826 
827 	/* When was the last time that we heard from this transport? We use
828 	 * this to pick new active and retran paths.
829 	 */
830 	ktime_t last_time_heard;
831 
832 	/* When was the last time that we sent a chunk using this
833 	 * transport? We use this to check for idle transports
834 	 */
835 	unsigned long last_time_sent;
836 
837 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
838 	 * indication based on ECNE chunk.
839 	 */
840 	unsigned long last_time_ecne_reduced;
841 
842 	/* This is the max_retrans value for the transport and will
843 	 * be initialized from the assocs value.  This can be changed
844 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
845 	 */
846 	__u16 pathmaxrxt;
847 
848 	/* This is the partially failed retrans value for the transport
849 	 * and will be initialized from the assocs value.  This can be changed
850 	 * using the SCTP_PEER_ADDR_THLDS socket option
851 	 */
852 	int pf_retrans;
853 	/* PMTU	      : The current known path MTU.  */
854 	__u32 pathmtu;
855 
856 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
857 	__u32 param_flags;
858 
859 	/* The number of times INIT has been sent on this transport. */
860 	int init_sent_count;
861 
862 	/* state       : The current state of this destination,
863 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
864 	 */
865 	int state;
866 
867 	/* These are the error stats for this destination.  */
868 
869 	/* Error count : The current error count for this destination.	*/
870 	unsigned short error_count;
871 
872 	/* Per	       : A timer used by each destination.
873 	 * Destination :
874 	 * Timer       :
875 	 *
876 	 * [Everywhere else in the text this is called T3-rtx. -ed]
877 	 */
878 	struct timer_list T3_rtx_timer;
879 
880 	/* Heartbeat timer is per destination. */
881 	struct timer_list hb_timer;
882 
883 	/* Timer to handle ICMP proto unreachable envets */
884 	struct timer_list proto_unreach_timer;
885 
886 	/* Timer to handler reconf chunk rtx */
887 	struct timer_list reconf_timer;
888 
889 	/* Since we're using per-destination retransmission timers
890 	 * (see above), we're also using per-destination "transmitted"
891 	 * queues.  This probably ought to be a private struct
892 	 * accessible only within the outqueue, but it's not, yet.
893 	 */
894 	struct list_head transmitted;
895 
896 	/* We build bundle-able packets for this transport here.  */
897 	struct sctp_packet packet;
898 
899 	/* This is the list of transports that have chunks to send.  */
900 	struct list_head send_ready;
901 
902 	/* State information saved for SFR_CACC algorithm. The key
903 	 * idea in SFR_CACC is to maintain state at the sender on a
904 	 * per-destination basis when a changeover happens.
905 	 *	char changeover_active;
906 	 *	char cycling_changeover;
907 	 *	__u32 next_tsn_at_change;
908 	 *	char cacc_saw_newack;
909 	 */
910 	struct {
911 		/* An unsigned integer, which stores the next TSN to be
912 		 * used by the sender, at the moment of changeover.
913 		 */
914 		__u32 next_tsn_at_change;
915 
916 		/* A flag which indicates the occurrence of a changeover */
917 		char changeover_active;
918 
919 		/* A flag which indicates whether the change of primary is
920 		 * the first switch to this destination address during an
921 		 * active switch.
922 		 */
923 		char cycling_changeover;
924 
925 		/* A temporary flag, which is used during the processing of
926 		 * a SACK to estimate the causative TSN(s)'s group.
927 		 */
928 		char cacc_saw_newack;
929 	} cacc;
930 
931 	/* 64-bit random number sent with heartbeat. */
932 	__u64 hb_nonce;
933 
934 	struct rcu_head rcu;
935 };
936 
937 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
938 					  gfp_t);
939 void sctp_transport_set_owner(struct sctp_transport *,
940 			      struct sctp_association *);
941 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
942 			  struct sctp_sock *);
943 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
944 void sctp_transport_free(struct sctp_transport *);
945 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
946 void sctp_transport_reset_hb_timer(struct sctp_transport *);
947 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
948 int sctp_transport_hold(struct sctp_transport *);
949 void sctp_transport_put(struct sctp_transport *);
950 void sctp_transport_update_rto(struct sctp_transport *, __u32);
951 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
952 void sctp_transport_lower_cwnd(struct sctp_transport *t,
953 			       enum sctp_lower_cwnd reason);
954 void sctp_transport_burst_limited(struct sctp_transport *);
955 void sctp_transport_burst_reset(struct sctp_transport *);
956 unsigned long sctp_transport_timeout(struct sctp_transport *);
957 void sctp_transport_reset(struct sctp_transport *t);
958 void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
959 void sctp_transport_immediate_rtx(struct sctp_transport *);
960 void sctp_transport_dst_release(struct sctp_transport *t);
961 void sctp_transport_dst_confirm(struct sctp_transport *t);
962 
963 
964 /* This is the structure we use to queue packets as they come into
965  * SCTP.  We write packets to it and read chunks from it.
966  */
967 struct sctp_inq {
968 	/* This is actually a queue of sctp_chunk each
969 	 * containing a partially decoded packet.
970 	 */
971 	struct list_head in_chunk_list;
972 	/* This is the packet which is currently off the in queue and is
973 	 * being worked on through the inbound chunk processing.
974 	 */
975 	struct sctp_chunk *in_progress;
976 
977 	/* This is the delayed task to finish delivering inbound
978 	 * messages.
979 	 */
980 	struct work_struct immediate;
981 };
982 
983 void sctp_inq_init(struct sctp_inq *);
984 void sctp_inq_free(struct sctp_inq *);
985 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
986 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
987 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
988 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
989 
990 /* This is the structure we use to hold outbound chunks.  You push
991  * chunks in and they automatically pop out the other end as bundled
992  * packets (it calls (*output_handler)()).
993  *
994  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
995  * and 8.2 of the v13 draft.
996  *
997  * It handles retransmissions.	The connection to the timeout portion
998  * of the state machine is through sctp_..._timeout() and timeout_handler.
999  *
1000  * If you feed it SACKs, it will eat them.
1001  *
1002  * If you give it big chunks, it will fragment them.
1003  *
1004  * It assigns TSN's to data chunks.  This happens at the last possible
1005  * instant before transmission.
1006  *
1007  * When free()'d, it empties itself out via output_handler().
1008  */
1009 struct sctp_outq {
1010 	struct sctp_association *asoc;
1011 
1012 	/* Data pending that has never been transmitted.  */
1013 	struct list_head out_chunk_list;
1014 
1015 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1016 
1017 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1018 	unsigned int error;
1019 
1020 	/* These are control chunks we want to send.  */
1021 	struct list_head control_chunk_list;
1022 
1023 	/* These are chunks that have been sacked but are above the
1024 	 * CTSN, or cumulative tsn ack point.
1025 	 */
1026 	struct list_head sacked;
1027 
1028 	/* Put chunks on this list to schedule them for
1029 	 * retransmission.
1030 	 */
1031 	struct list_head retransmit;
1032 
1033 	/* Put chunks on this list to save them for FWD TSN processing as
1034 	 * they were abandoned.
1035 	 */
1036 	struct list_head abandoned;
1037 
1038 	/* How many unackd bytes do we have in-flight?	*/
1039 	__u32 outstanding_bytes;
1040 
1041 	/* Are we doing fast-rtx on this queue */
1042 	char fast_rtx;
1043 
1044 	/* Corked? */
1045 	char cork;
1046 };
1047 
1048 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1049 void sctp_outq_teardown(struct sctp_outq *);
1050 void sctp_outq_free(struct sctp_outq*);
1051 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1052 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1053 int sctp_outq_is_empty(const struct sctp_outq *);
1054 void sctp_outq_restart(struct sctp_outq *);
1055 
1056 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1057 		     enum sctp_retransmit_reason reason);
1058 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1059 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1060 void sctp_prsctp_prune(struct sctp_association *asoc,
1061 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1062 /* Uncork and flush an outqueue.  */
1063 static inline void sctp_outq_cork(struct sctp_outq *q)
1064 {
1065 	q->cork = 1;
1066 }
1067 
1068 /* SCTP skb control block.
1069  * sctp_input_cb is currently used on rx and sock rx queue
1070  */
1071 struct sctp_input_cb {
1072 	union {
1073 		struct inet_skb_parm	h4;
1074 #if IS_ENABLED(CONFIG_IPV6)
1075 		struct inet6_skb_parm	h6;
1076 #endif
1077 	} header;
1078 	struct sctp_chunk *chunk;
1079 	struct sctp_af *af;
1080 };
1081 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1082 
1083 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1084 {
1085 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1086 
1087 	return chunk->head_skb ? : skb;
1088 }
1089 
1090 /* These bind address data fields common between endpoints and associations */
1091 struct sctp_bind_addr {
1092 
1093 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1094 	 *
1095 	 * SCTP Port:	The local SCTP port number the endpoint is
1096 	 *		bound to.
1097 	 */
1098 	__u16 port;
1099 
1100 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1101 	 *
1102 	 * Address List: The list of IP addresses that this instance
1103 	 *	has bound.  This information is passed to one's
1104 	 *	peer(s) in INIT and INIT ACK chunks.
1105 	 */
1106 	struct list_head address_list;
1107 };
1108 
1109 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1110 void sctp_bind_addr_free(struct sctp_bind_addr *);
1111 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1112 			const struct sctp_bind_addr *src,
1113 			enum sctp_scope scope, gfp_t gfp,
1114 			int flags);
1115 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1116 			const struct sctp_bind_addr *src,
1117 			gfp_t gfp);
1118 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1119 		       int new_size, __u8 addr_state, gfp_t gfp);
1120 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1121 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1122 			 struct sctp_sock *);
1123 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1124 			 struct sctp_sock *, struct sctp_sock *);
1125 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1126 			 const union sctp_addr *addr);
1127 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1128 					const union sctp_addr	*addrs,
1129 					int			addrcnt,
1130 					struct sctp_sock	*opt);
1131 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1132 					 int *addrs_len,
1133 					 gfp_t gfp);
1134 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1135 			   __u16 port, gfp_t gfp);
1136 
1137 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1138 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1139 		  const enum sctp_scope scope);
1140 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1141 int sctp_is_ep_boundall(struct sock *sk);
1142 
1143 
1144 /* What type of endpoint?  */
1145 enum sctp_endpoint_type {
1146 	SCTP_EP_TYPE_SOCKET,
1147 	SCTP_EP_TYPE_ASSOCIATION,
1148 };
1149 
1150 /*
1151  * A common base class to bridge the implmentation view of a
1152  * socket (usually listening) endpoint versus an association's
1153  * local endpoint.
1154  * This common structure is useful for several purposes:
1155  *   1) Common interface for lookup routines.
1156  *	a) Subfunctions work for either endpoint or association
1157  *	b) Single interface to lookup allows hiding the lookup lock rather
1158  *	   than acquiring it externally.
1159  *   2) Common interface for the inbound chunk handling/state machine.
1160  *   3) Common object handling routines for reference counting, etc.
1161  *   4) Disentangle association lookup from endpoint lookup, where we
1162  *	do not have to find our endpoint to find our association.
1163  *
1164  */
1165 
1166 struct sctp_ep_common {
1167 	/* Fields to help us manage our entries in the hash tables. */
1168 	struct hlist_node node;
1169 	int hashent;
1170 
1171 	/* Runtime type information.  What kind of endpoint is this? */
1172 	enum sctp_endpoint_type type;
1173 
1174 	/* Some fields to help us manage this object.
1175 	 *   refcnt   - Reference count access to this object.
1176 	 *   dead     - Do not attempt to use this object.
1177 	 */
1178 	refcount_t    refcnt;
1179 	bool	    dead;
1180 
1181 	/* What socket does this endpoint belong to?  */
1182 	struct sock *sk;
1183 
1184 	/* This is where we receive inbound chunks.  */
1185 	struct sctp_inq	  inqueue;
1186 
1187 	/* This substructure includes the defining parameters of the
1188 	 * endpoint:
1189 	 * bind_addr.port is our shared port number.
1190 	 * bind_addr.address_list is our set of local IP addresses.
1191 	 */
1192 	struct sctp_bind_addr bind_addr;
1193 };
1194 
1195 
1196 /* RFC Section 1.4 Key Terms
1197  *
1198  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1199  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1200  *   combination of a set of eligible destination transport addresses to
1201  *   which SCTP packets can be sent and a set of eligible source
1202  *   transport addresses from which SCTP packets can be received.
1203  *   All transport addresses used by an SCTP endpoint must use the
1204  *   same port number, but can use multiple IP addresses. A transport
1205  *   address used by an SCTP endpoint must not be used by another
1206  *   SCTP endpoint. In other words, a transport address is unique
1207  *   to an SCTP endpoint.
1208  *
1209  * From an implementation perspective, each socket has one of these.
1210  * A TCP-style socket will have exactly one association on one of
1211  * these.  An UDP-style socket will have multiple associations hanging
1212  * off one of these.
1213  */
1214 
1215 struct sctp_endpoint {
1216 	/* Common substructure for endpoint and association. */
1217 	struct sctp_ep_common base;
1218 
1219 	/* Associations: A list of current associations and mappings
1220 	 *	      to the data consumers for each association. This
1221 	 *	      may be in the form of a hash table or other
1222 	 *	      implementation dependent structure. The data
1223 	 *	      consumers may be process identification
1224 	 *	      information such as file descriptors, named pipe
1225 	 *	      pointer, or table pointers dependent on how SCTP
1226 	 *	      is implemented.
1227 	 */
1228 	/* This is really a list of struct sctp_association entries. */
1229 	struct list_head asocs;
1230 
1231 	/* Secret Key: A secret key used by this endpoint to compute
1232 	 *	      the MAC.	This SHOULD be a cryptographic quality
1233 	 *	      random number with a sufficient length.
1234 	 *	      Discussion in [RFC1750] can be helpful in
1235 	 *	      selection of the key.
1236 	 */
1237 	__u8 secret_key[SCTP_SECRET_SIZE];
1238 
1239  	/* digest:  This is a digest of the sctp cookie.  This field is
1240  	 * 	    only used on the receive path when we try to validate
1241  	 * 	    that the cookie has not been tampered with.  We put
1242  	 * 	    this here so we pre-allocate this once and can re-use
1243  	 * 	    on every receive.
1244  	 */
1245  	__u8 *digest;
1246 
1247 	/* sendbuf acct. policy.	*/
1248 	__u32 sndbuf_policy;
1249 
1250 	/* rcvbuf acct. policy.	*/
1251 	__u32 rcvbuf_policy;
1252 
1253 	/* SCTP AUTH: array of the HMACs that will be allocated
1254 	 * we need this per association so that we don't serialize
1255 	 */
1256 	struct crypto_shash **auth_hmacs;
1257 
1258 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1259 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1260 
1261 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1262 	struct sctp_chunks_param *auth_chunk_list;
1263 
1264 	/* SCTP-AUTH: endpoint shared keys */
1265 	struct list_head endpoint_shared_keys;
1266 	__u16 active_key_id;
1267 	__u8  auth_enable:1,
1268 	      prsctp_enable:1,
1269 	      reconf_enable:1;
1270 
1271 	__u8  strreset_enable;
1272 };
1273 
1274 /* Recover the outter endpoint structure. */
1275 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1276 {
1277 	struct sctp_endpoint *ep;
1278 
1279 	ep = container_of(base, struct sctp_endpoint, base);
1280 	return ep;
1281 }
1282 
1283 /* These are function signatures for manipulating endpoints.  */
1284 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1285 void sctp_endpoint_free(struct sctp_endpoint *);
1286 void sctp_endpoint_put(struct sctp_endpoint *);
1287 void sctp_endpoint_hold(struct sctp_endpoint *);
1288 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1289 struct sctp_association *sctp_endpoint_lookup_assoc(
1290 	const struct sctp_endpoint *ep,
1291 	const union sctp_addr *paddr,
1292 	struct sctp_transport **);
1293 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1294 				const union sctp_addr *);
1295 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1296 					struct net *, const union sctp_addr *);
1297 int sctp_has_association(struct net *net, const union sctp_addr *laddr,
1298 			 const union sctp_addr *paddr);
1299 
1300 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1301 		     const struct sctp_association *asoc,
1302 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1303 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1304 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1305 		      const union sctp_addr *peer,
1306 		      struct sctp_init_chunk *init, gfp_t gfp);
1307 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1308 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1309 
1310 struct sctp_inithdr_host {
1311 	__u32 init_tag;
1312 	__u32 a_rwnd;
1313 	__u16 num_outbound_streams;
1314 	__u16 num_inbound_streams;
1315 	__u32 initial_tsn;
1316 };
1317 
1318 struct sctp_stream_out {
1319 	__u16	ssn;
1320 	__u8	state;
1321 	__u64	abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1322 	__u64	abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1323 };
1324 
1325 struct sctp_stream_in {
1326 	__u16	ssn;
1327 };
1328 
1329 struct sctp_stream {
1330 	struct sctp_stream_out *out;
1331 	struct sctp_stream_in *in;
1332 	__u16 outcnt;
1333 	__u16 incnt;
1334 };
1335 
1336 #define SCTP_STREAM_CLOSED		0x00
1337 #define SCTP_STREAM_OPEN		0x01
1338 
1339 /* SCTP_GET_ASSOC_STATS counters */
1340 struct sctp_priv_assoc_stats {
1341 	/* Maximum observed rto in the association during subsequent
1342 	 * observations. Value is set to 0 if no RTO measurement took place
1343 	 * The transport where the max_rto was observed is returned in
1344 	 * obs_rto_ipaddr
1345 	 */
1346 	struct sockaddr_storage obs_rto_ipaddr;
1347 	__u64 max_obs_rto;
1348 	/* Total In and Out SACKs received and sent */
1349 	__u64 isacks;
1350 	__u64 osacks;
1351 	/* Total In and Out packets received and sent */
1352 	__u64 opackets;
1353 	__u64 ipackets;
1354 	/* Total retransmitted chunks */
1355 	__u64 rtxchunks;
1356 	/* TSN received > next expected */
1357 	__u64 outofseqtsns;
1358 	/* Duplicate Chunks received */
1359 	__u64 idupchunks;
1360 	/* Gap Ack Blocks received */
1361 	__u64 gapcnt;
1362 	/* Unordered data chunks sent and received */
1363 	__u64 ouodchunks;
1364 	__u64 iuodchunks;
1365 	/* Ordered data chunks sent and received */
1366 	__u64 oodchunks;
1367 	__u64 iodchunks;
1368 	/* Control chunks sent and received */
1369 	__u64 octrlchunks;
1370 	__u64 ictrlchunks;
1371 };
1372 
1373 /* RFC2960
1374  *
1375  * 12. Recommended Transmission Control Block (TCB) Parameters
1376  *
1377  * This section details a recommended set of parameters that should
1378  * be contained within the TCB for an implementation. This section is
1379  * for illustrative purposes and should not be deemed as requirements
1380  * on an implementation or as an exhaustive list of all parameters
1381  * inside an SCTP TCB. Each implementation may need its own additional
1382  * parameters for optimization.
1383  */
1384 
1385 
1386 /* Here we have information about each individual association. */
1387 struct sctp_association {
1388 
1389 	/* A base structure common to endpoint and association.
1390 	 * In this context, it represents the associations's view
1391 	 * of the local endpoint of the association.
1392 	 */
1393 	struct sctp_ep_common base;
1394 
1395 	/* Associations on the same socket. */
1396 	struct list_head asocs;
1397 
1398 	/* association id. */
1399 	sctp_assoc_t assoc_id;
1400 
1401 	/* This is our parent endpoint.	 */
1402 	struct sctp_endpoint *ep;
1403 
1404 	/* These are those association elements needed in the cookie.  */
1405 	struct sctp_cookie c;
1406 
1407 	/* This is all information about our peer.  */
1408 	struct {
1409 		/* transport_addr_list
1410 		 *
1411 		 * Peer	       : A list of SCTP transport addresses that the
1412 		 * Transport   : peer is bound to. This information is derived
1413 		 * Address     : from the INIT or INIT ACK and is used to
1414 		 * List	       : associate an inbound packet with a given
1415 		 *	       : association. Normally this information is
1416 		 *	       : hashed or keyed for quick lookup and access
1417 		 *	       : of the TCB.
1418 		 *	       : The list is also initialized with the list
1419 		 *	       : of addresses passed with the sctp_connectx()
1420 		 *	       : call.
1421 		 *
1422 		 * It is a list of SCTP_transport's.
1423 		 */
1424 		struct list_head transport_addr_list;
1425 
1426 		/* rwnd
1427 		 *
1428 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1429 		 */
1430 		__u32 rwnd;
1431 
1432 		/* transport_count
1433 		 *
1434 		 * Peer        : A count of the number of peer addresses
1435 		 * Transport   : in the Peer Transport Address List.
1436 		 * Address     :
1437 		 * Count       :
1438 		 */
1439 		__u16 transport_count;
1440 
1441 		/* port
1442 		 *   The transport layer port number.
1443 		 */
1444 		__u16 port;
1445 
1446 		/* primary_path
1447 		 *
1448 		 * Primary     : This is the current primary destination
1449 		 * Path	       : transport address of the peer endpoint.  It
1450 		 *	       : may also specify a source transport address
1451 		 *	       : on this endpoint.
1452 		 *
1453 		 * All of these paths live on transport_addr_list.
1454 		 *
1455 		 * At the bakeoffs, we discovered that the intent of
1456 		 * primaryPath is that it only changes when the ULP
1457 		 * asks to have it changed.  We add the activePath to
1458 		 * designate the connection we are currently using to
1459 		 * transmit new data and most control chunks.
1460 		 */
1461 		struct sctp_transport *primary_path;
1462 
1463 		/* Cache the primary path address here, when we
1464 		 * need a an address for msg_name.
1465 		 */
1466 		union sctp_addr primary_addr;
1467 
1468 		/* active_path
1469 		 *   The path that we are currently using to
1470 		 *   transmit new data and most control chunks.
1471 		 */
1472 		struct sctp_transport *active_path;
1473 
1474 		/* retran_path
1475 		 *
1476 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1477 		 * ...
1478 		 * Furthermore, when its peer is multi-homed, an
1479 		 * endpoint SHOULD try to retransmit a chunk to an
1480 		 * active destination transport address that is
1481 		 * different from the last destination address to
1482 		 * which the DATA chunk was sent.
1483 		 */
1484 		struct sctp_transport *retran_path;
1485 
1486 		/* Pointer to last transport I have sent on.  */
1487 		struct sctp_transport *last_sent_to;
1488 
1489 		/* This is the last transport I have received DATA on.	*/
1490 		struct sctp_transport *last_data_from;
1491 
1492 		/*
1493 		 * Mapping  An array of bits or bytes indicating which out of
1494 		 * Array    order TSN's have been received (relative to the
1495 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1496 		 *	    order packets have been received, this array
1497 		 *	    will be set to all zero. This structure may be
1498 		 *	    in the form of a circular buffer or bit array.
1499 		 *
1500 		 * Last Rcvd   : This is the last TSN received in
1501 		 * TSN	       : sequence. This value is set initially by
1502 		 *	       : taking the peer's Initial TSN, received in
1503 		 *	       : the INIT or INIT ACK chunk, and subtracting
1504 		 *	       : one from it.
1505 		 *
1506 		 * Throughout most of the specification this is called the
1507 		 * "Cumulative TSN ACK Point".	In this case, we
1508 		 * ignore the advice in 12.2 in favour of the term
1509 		 * used in the bulk of the text.  This value is hidden
1510 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1511 		 */
1512 		struct sctp_tsnmap tsn_map;
1513 
1514 		/* This mask is used to disable sending the ASCONF chunk
1515 		 * with specified parameter to peer.
1516 		 */
1517 		__be16 addip_disabled_mask;
1518 
1519 		/* These are capabilities which our peer advertised.  */
1520 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1521 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1522 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1523 			hostname_address:1, /* Peer understands DNS addresses? */
1524 			asconf_capable:1,   /* Does peer support ADDIP? */
1525 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1526 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1527 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1528 
1529 		/* sack_needed : This flag indicates if the next received
1530 		 *             : packet is to be responded to with a
1531 		 *             : SACK. This is initialized to 0.  When a packet
1532 		 *             : is received sack_cnt is incremented. If this value
1533 		 *             : reaches 2 or more, a SACK is sent and the
1534 		 *             : value is reset to 0. Note: This is used only
1535 		 *             : when no DATA chunks are received out of
1536 		 *             : order.  When DATA chunks are out of order,
1537 		 *             : SACK's are not delayed (see Section 6).
1538 		 */
1539 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1540 			sack_generation:1,
1541 			zero_window_announced:1;
1542 		__u32	sack_cnt;
1543 
1544 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1545 
1546 		struct sctp_inithdr_host i;
1547 		void *cookie;
1548 		int cookie_len;
1549 
1550 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1551 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1552 		 * Initial TSN Value minus 1
1553 		 */
1554 		__u32 addip_serial;
1555 
1556 		/* SCTP-AUTH: We need to know pears random number, hmac list
1557 		 * and authenticated chunk list.  All that is part of the
1558 		 * cookie and these are just pointers to those locations
1559 		 */
1560 		struct sctp_random_param *peer_random;
1561 		struct sctp_chunks_param *peer_chunks;
1562 		struct sctp_hmac_algo_param *peer_hmacs;
1563 	} peer;
1564 
1565 	/* State       : A state variable indicating what state the
1566 	 *	       : association is in, i.e. COOKIE-WAIT,
1567 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1568 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1569 	 *
1570 	 *		Note: No "CLOSED" state is illustrated since if a
1571 	 *		association is "CLOSED" its TCB SHOULD be removed.
1572 	 *
1573 	 *		In this implementation we DO have a CLOSED
1574 	 *		state which is used during initiation and shutdown.
1575 	 *
1576 	 *		State takes values from SCTP_STATE_*.
1577 	 */
1578 	enum sctp_state state;
1579 
1580 	/* Overall     : The overall association error count.
1581 	 * Error Count : [Clear this any time I get something.]
1582 	 */
1583 	int overall_error_count;
1584 
1585 	/* The cookie life I award for any cookie.  */
1586 	ktime_t cookie_life;
1587 
1588 	/* These are the association's initial, max, and min RTO values.
1589 	 * These values will be initialized by system defaults, but can
1590 	 * be modified via the SCTP_RTOINFO socket option.
1591 	 */
1592 	unsigned long rto_initial;
1593 	unsigned long rto_max;
1594 	unsigned long rto_min;
1595 
1596 	/* Maximum number of new data packets that can be sent in a burst.  */
1597 	int max_burst;
1598 
1599 	/* This is the max_retrans value for the association.  This value will
1600 	 * be initialized initialized from system defaults, but can be
1601 	 * modified by the SCTP_ASSOCINFO socket option.
1602 	 */
1603 	int max_retrans;
1604 
1605 	/* This is the partially failed retrans value for the transport
1606 	 * and will be initialized from the assocs value.  This can be
1607 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1608 	 */
1609 	int pf_retrans;
1610 
1611 	/* Maximum number of times the endpoint will retransmit INIT  */
1612 	__u16 max_init_attempts;
1613 
1614 	/* How many times have we resent an INIT? */
1615 	__u16 init_retries;
1616 
1617 	/* The largest timeout or RTO value to use in attempting an INIT */
1618 	unsigned long max_init_timeo;
1619 
1620 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1621 	 * the destination address every heartbeat interval. This value
1622 	 * will be inherited by all new transports.
1623 	 */
1624 	unsigned long hbinterval;
1625 
1626 	/* This is the max_retrans value for new transports in the
1627 	 * association.
1628 	 */
1629 	__u16 pathmaxrxt;
1630 
1631 	/* Flag that path mtu update is pending */
1632 	__u8   pmtu_pending;
1633 
1634 	/* Association : The smallest PMTU discovered for all of the
1635 	 * PMTU	       : peer's transport addresses.
1636 	 */
1637 	__u32 pathmtu;
1638 
1639 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1640 	__u32 param_flags;
1641 
1642 	__u32 sackfreq;
1643 	/* SACK delay timeout */
1644 	unsigned long sackdelay;
1645 
1646 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1647 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1648 
1649 	/* Transport to which SHUTDOWN chunk was last sent.  */
1650 	struct sctp_transport *shutdown_last_sent_to;
1651 
1652 	/* Transport to which INIT chunk was last sent.  */
1653 	struct sctp_transport *init_last_sent_to;
1654 
1655 	/* How many times have we resent a SHUTDOWN */
1656 	int shutdown_retries;
1657 
1658 	/* Next TSN    : The next TSN number to be assigned to a new
1659 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1660 	 *	       : ACK chunk to the peer and incremented each
1661 	 *	       : time a DATA chunk is assigned a TSN
1662 	 *	       : (normally just prior to transmit or during
1663 	 *	       : fragmentation).
1664 	 */
1665 	__u32 next_tsn;
1666 
1667 	/*
1668 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1669 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1670 	 *	       : received in the INIT or INIT ACK chunk, and
1671 	 *	       : subtracting one from it.
1672 	 *
1673 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1674 	 */
1675 
1676 	__u32 ctsn_ack_point;
1677 
1678 	/* PR-SCTP Advanced.Peer.Ack.Point */
1679 	__u32 adv_peer_ack_point;
1680 
1681 	/* Highest TSN that is acknowledged by incoming SACKs. */
1682 	__u32 highest_sacked;
1683 
1684 	/* TSN marking the fast recovery exit point */
1685 	__u32 fast_recovery_exit;
1686 
1687 	/* Flag to track the current fast recovery state */
1688 	__u8 fast_recovery;
1689 
1690 	/* The number of unacknowledged data chunks.  Reported through
1691 	 * the SCTP_STATUS sockopt.
1692 	 */
1693 	__u16 unack_data;
1694 
1695 	/* The total number of data chunks that we've had to retransmit
1696 	 * as the result of a T3 timer expiration
1697 	 */
1698 	__u32 rtx_data_chunks;
1699 
1700 	/* This is the association's receive buffer space.  This value is used
1701 	 * to set a_rwnd field in an INIT or a SACK chunk.
1702 	 */
1703 	__u32 rwnd;
1704 
1705 	/* This is the last advertised value of rwnd over a SACK chunk. */
1706 	__u32 a_rwnd;
1707 
1708 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1709 	 * to slop over a maximum of the association's frag_point.
1710 	 */
1711 	__u32 rwnd_over;
1712 
1713 	/* Keeps treack of rwnd pressure.  This happens when we have
1714 	 * a window, but not recevie buffer (i.e small packets).  This one
1715 	 * is releases slowly (1 PMTU at a time ).
1716 	 */
1717 	__u32 rwnd_press;
1718 
1719 	/* This is the sndbuf size in use for the association.
1720 	 * This corresponds to the sndbuf size for the association,
1721 	 * as specified in the sk->sndbuf.
1722 	 */
1723 	int sndbuf_used;
1724 
1725 	/* This is the amount of memory that this association has allocated
1726 	 * in the receive path at any given time.
1727 	 */
1728 	atomic_t rmem_alloc;
1729 
1730 	/* This is the wait queue head for send requests waiting on
1731 	 * the association sndbuf space.
1732 	 */
1733 	wait_queue_head_t	wait;
1734 
1735 	/* The message size at which SCTP fragmentation will occur. */
1736 	__u32 frag_point;
1737 	__u32 user_frag;
1738 
1739 	/* Counter used to count INIT errors. */
1740 	int init_err_counter;
1741 
1742 	/* Count the number of INIT cycles (for doubling timeout). */
1743 	int init_cycle;
1744 
1745 	/* Default send parameters. */
1746 	__u16 default_stream;
1747 	__u16 default_flags;
1748 	__u32 default_ppid;
1749 	__u32 default_context;
1750 	__u32 default_timetolive;
1751 
1752 	/* Default receive parameters */
1753 	__u32 default_rcv_context;
1754 
1755 	/* Stream arrays */
1756 	struct sctp_stream stream;
1757 
1758 	/* All outbound chunks go through this structure.  */
1759 	struct sctp_outq outqueue;
1760 
1761 	/* A smart pipe that will handle reordering and fragmentation,
1762 	 * as well as handle passing events up to the ULP.
1763 	 */
1764 	struct sctp_ulpq ulpq;
1765 
1766 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1767 	__u32 last_ecne_tsn;
1768 
1769 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1770 	__u32 last_cwr_tsn;
1771 
1772 	/* How many duplicated TSNs have we seen?  */
1773 	int numduptsns;
1774 
1775 	/* These are to support
1776 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1777 	 *  and Enforcement of Flow and Message Limits"
1778 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1779 	 * or "ADDIP" for short.
1780 	 */
1781 
1782 
1783 
1784 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1785 	 *
1786 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1787 	 * unacknowledged at any one time.  If a sender, after sending
1788 	 * an ASCONF chunk, decides it needs to transfer another
1789 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1790 	 * returns from the previous ASCONF Chunk before sending a
1791 	 * subsequent ASCONF. Note this restriction binds each side,
1792 	 * so at any time two ASCONF may be in-transit on any given
1793 	 * association (one sent from each endpoint).
1794 	 *
1795 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1796 	 * not have an ASCONF in flight, this is NULL.]
1797 	 */
1798 	struct sctp_chunk *addip_last_asconf;
1799 
1800 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1801 	 *
1802 	 * This is needed to implement itmes E1 - E4 of the updated
1803 	 * spec.  Here is the justification:
1804 	 *
1805 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1806 	 * we now need the ability to cache multiple ACKs.  The section
1807 	 * describes in detail how they are cached and cleaned up.
1808 	 */
1809 	struct list_head asconf_ack_list;
1810 
1811 	/* These ASCONF chunks are waiting to be sent.
1812 	 *
1813 	 * These chunaks can't be pushed to outqueue until receiving
1814 	 * ASCONF_ACK for the previous ASCONF indicated by
1815 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1816 	 * is in flight at any time.
1817 	 *
1818 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1819 	 *
1820 	 * In defining the ASCONF Chunk transfer procedures, it is
1821 	 * essential that these transfers MUST NOT cause congestion
1822 	 * within the network.	To achieve this, we place these
1823 	 * restrictions on the transfer of ASCONF Chunks:
1824 	 *
1825 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1826 	 * unacknowledged at any one time.  If a sender, after sending
1827 	 * an ASCONF chunk, decides it needs to transfer another
1828 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1829 	 * returns from the previous ASCONF Chunk before sending a
1830 	 * subsequent ASCONF. Note this restriction binds each side,
1831 	 * so at any time two ASCONF may be in-transit on any given
1832 	 * association (one sent from each endpoint).
1833 	 *
1834 	 *
1835 	 * [I really think this is EXACTLY the sort of intelligence
1836 	 *  which already resides in sctp_outq.	 Please move this
1837 	 *  queue and its supporting logic down there.	--piggy]
1838 	 */
1839 	struct list_head addip_chunk_list;
1840 
1841 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1842 	 *
1843 	 * A2) A serial number should be assigned to the Chunk. The
1844 	 * serial number SHOULD be a monotonically increasing
1845 	 * number. The serial number SHOULD be initialized at
1846 	 * the start of the association to the same value as the
1847 	 * Initial TSN and every time a new ASCONF chunk is created
1848 	 * it is incremented by one after assigning the serial number
1849 	 * to the newly created chunk.
1850 	 *
1851 	 * ADDIP
1852 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1853 	 *
1854 	 * Serial Number : 32 bits (unsigned integer)
1855 	 *
1856 	 * This value represents a Serial Number for the ASCONF
1857 	 * Chunk. The valid range of Serial Number is from 0 to
1858 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1859 	 * after reaching 4294967295.
1860 	 */
1861 	__u32 addip_serial;
1862 	int src_out_of_asoc_ok;
1863 	union sctp_addr *asconf_addr_del_pending;
1864 	struct sctp_transport *new_transport;
1865 
1866 	/* SCTP AUTH: list of the endpoint shared keys.  These
1867 	 * keys are provided out of band by the user applicaton
1868 	 * and can't change during the lifetime of the association
1869 	 */
1870 	struct list_head endpoint_shared_keys;
1871 
1872 	/* SCTP AUTH:
1873 	 * The current generated assocaition shared key (secret)
1874 	 */
1875 	struct sctp_auth_bytes *asoc_shared_key;
1876 
1877 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1878 	 * that we support.
1879 	 */
1880 	__u16 default_hmac_id;
1881 
1882 	__u16 active_key_id;
1883 
1884 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
1885 	     temp:1,		/* Is it a temporary association? */
1886 	     force_delay:1,
1887 	     prsctp_enable:1,
1888 	     reconf_enable:1;
1889 
1890 	__u8 strreset_enable;
1891 	__u8 strreset_outstanding; /* request param count on the fly */
1892 
1893 	__u32 strreset_outseq; /* Update after receiving response */
1894 	__u32 strreset_inseq; /* Update after receiving request */
1895 	__u32 strreset_result[2]; /* save the results of last 2 responses */
1896 
1897 	struct sctp_chunk *strreset_chunk; /* save request chunk */
1898 
1899 	struct sctp_priv_assoc_stats stats;
1900 
1901 	int sent_cnt_removable;
1902 
1903 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1904 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1905 };
1906 
1907 
1908 /* An eyecatcher for determining if we are really looking at an
1909  * association data structure.
1910  */
1911 enum {
1912 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1913 };
1914 
1915 /* Recover the outter association structure. */
1916 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1917 {
1918 	struct sctp_association *asoc;
1919 
1920 	asoc = container_of(base, struct sctp_association, base);
1921 	return asoc;
1922 }
1923 
1924 /* These are function signatures for manipulating associations.	 */
1925 
1926 
1927 struct sctp_association *
1928 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
1929 		     enum sctp_scope scope, gfp_t gfp);
1930 void sctp_association_free(struct sctp_association *);
1931 void sctp_association_put(struct sctp_association *);
1932 void sctp_association_hold(struct sctp_association *);
1933 
1934 struct sctp_transport *sctp_assoc_choose_alter_transport(
1935 	struct sctp_association *, struct sctp_transport *);
1936 void sctp_assoc_update_retran_path(struct sctp_association *);
1937 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1938 					  const union sctp_addr *);
1939 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1940 			    const union sctp_addr *laddr);
1941 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
1942 				     const union sctp_addr *address,
1943 				     const gfp_t gfp,
1944 				     const int peer_state);
1945 void sctp_assoc_del_peer(struct sctp_association *asoc,
1946 			 const union sctp_addr *addr);
1947 void sctp_assoc_rm_peer(struct sctp_association *asoc,
1948 			 struct sctp_transport *peer);
1949 void sctp_assoc_control_transport(struct sctp_association *asoc,
1950 				  struct sctp_transport *transport,
1951 				  enum sctp_transport_cmd command,
1952 				  sctp_sn_error_t error);
1953 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
1954 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
1955 					   struct net *,
1956 					   const union sctp_addr *,
1957 					   const union sctp_addr *);
1958 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
1959 int sctp_assoc_update(struct sctp_association *old,
1960 		      struct sctp_association *new);
1961 
1962 __u32 sctp_association_get_next_tsn(struct sctp_association *);
1963 
1964 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
1965 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
1966 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
1967 void sctp_assoc_set_primary(struct sctp_association *,
1968 			    struct sctp_transport *);
1969 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
1970 				    struct sctp_transport *);
1971 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
1972 				     enum sctp_scope scope, gfp_t gfp);
1973 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
1974 					 struct sctp_cookie*,
1975 					 gfp_t gfp);
1976 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
1977 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
1978 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1979 					const struct sctp_association *asoc,
1980 					__be32 serial);
1981 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
1982 
1983 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
1984 			const union sctp_addr *ss2);
1985 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
1986 
1987 /* A convenience structure to parse out SCTP specific CMSGs. */
1988 struct sctp_cmsgs {
1989 	struct sctp_initmsg *init;
1990 	struct sctp_sndrcvinfo *srinfo;
1991 	struct sctp_sndinfo *sinfo;
1992 };
1993 
1994 /* Structure for tracking memory objects */
1995 struct sctp_dbg_objcnt_entry {
1996 	char *label;
1997 	atomic_t *counter;
1998 };
1999 
2000 #endif /* __sctp_structs_h__ */
2001