xref: /openbmc/linux/include/net/sctp/structs.h (revision ab9ee8e3)
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_rtoinfo rtoinfo;
206 	struct sctp_paddrparams paddrparam;
207 	struct sctp_assocparams assocparams;
208 
209 	/*
210 	 * These two structures must be grouped together for the usercopy
211 	 * whitelist region.
212 	 */
213 	struct sctp_event_subscribe subscribe;
214 	struct sctp_initmsg initmsg;
215 
216 	int user_frag;
217 
218 	__u32 autoclose;
219 	__u32 adaptation_ind;
220 	__u32 pd_point;
221 	__u16	nodelay:1,
222 		disable_fragments:1,
223 		v4mapped:1,
224 		frag_interleave:1,
225 		recvrcvinfo:1,
226 		recvnxtinfo:1,
227 		data_ready_signalled:1;
228 
229 	atomic_t pd_mode;
230 	/* Receive to here while partial delivery is in effect. */
231 	struct sk_buff_head pd_lobby;
232 
233 	/* These must be the last fields, as they will skipped on copies,
234 	 * like on accept and peeloff operations
235 	 */
236 	struct list_head auto_asconf_list;
237 	int do_auto_asconf;
238 };
239 
240 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
241 {
242        return (struct sctp_sock *)sk;
243 }
244 
245 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
246 {
247        return (struct sock *)sp;
248 }
249 
250 #if IS_ENABLED(CONFIG_IPV6)
251 struct sctp6_sock {
252        struct sctp_sock  sctp;
253        struct ipv6_pinfo inet6;
254 };
255 #endif /* CONFIG_IPV6 */
256 
257 
258 /* This is our APPLICATION-SPECIFIC state cookie.
259  * THIS IS NOT DICTATED BY THE SPECIFICATION.
260  */
261 /* These are the parts of an association which we send in the cookie.
262  * Most of these are straight out of:
263  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
264  *
265  */
266 
267 struct sctp_cookie {
268 
269 	/* My	       : Tag expected in every inbound packet and sent
270 	 * Verification: in the INIT or INIT ACK chunk.
271 	 * Tag	       :
272 	 */
273 	__u32 my_vtag;
274 
275 	/* Peer's      : Tag expected in every outbound packet except
276 	 * Verification: in the INIT chunk.
277 	 * Tag	       :
278 	 */
279 	__u32 peer_vtag;
280 
281 	/* The rest of these are not from the spec, but really need to
282 	 * be in the cookie.
283 	 */
284 
285 	/* My Tie Tag  : Assist in discovering a restarting association. */
286 	__u32 my_ttag;
287 
288 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
289 	__u32 peer_ttag;
290 
291 	/* When does this cookie expire? */
292 	ktime_t expiration;
293 
294 	/* Number of inbound/outbound streams which are set
295 	 * and negotiated during the INIT process.
296 	 */
297 	__u16 sinit_num_ostreams;
298 	__u16 sinit_max_instreams;
299 
300 	/* This is the first sequence number I used.  */
301 	__u32 initial_tsn;
302 
303 	/* This holds the originating address of the INIT packet.  */
304 	union sctp_addr peer_addr;
305 
306 	/* IG Section 2.35.3
307 	 * Include the source port of the INIT-ACK
308 	 */
309 	__u16		my_port;
310 
311 	__u8 prsctp_capable;
312 
313 	/* Padding for future use */
314 	__u8 padding;
315 
316 	__u32 adaptation_ind;
317 
318 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
319 			 SCTP_AUTH_RANDOM_LENGTH];
320 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
321 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
322 
323 	/* This is a shim for my peer's INIT packet, followed by
324 	 * a copy of the raw address list of the association.
325 	 * The length of the raw address list is saved in the
326 	 * raw_addr_list_len field, which will be used at the time when
327 	 * the association TCB is re-constructed from the cookie.
328 	 */
329 	__u32 raw_addr_list_len;
330 	struct sctp_init_chunk peer_init[0];
331 };
332 
333 
334 /* The format of our cookie that we send to our peer. */
335 struct sctp_signed_cookie {
336 	__u8 signature[SCTP_SECRET_SIZE];
337 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
338 	struct sctp_cookie c;
339 } __packed;
340 
341 /* This is another convenience type to allocate memory for address
342  * params for the maximum size and pass such structures around
343  * internally.
344  */
345 union sctp_addr_param {
346 	struct sctp_paramhdr p;
347 	struct sctp_ipv4addr_param v4;
348 	struct sctp_ipv6addr_param v6;
349 };
350 
351 /* A convenience type to allow walking through the various
352  * parameters and avoid casting all over the place.
353  */
354 union sctp_params {
355 	void *v;
356 	struct sctp_paramhdr *p;
357 	struct sctp_cookie_preserve_param *life;
358 	struct sctp_hostname_param *dns;
359 	struct sctp_cookie_param *cookie;
360 	struct sctp_supported_addrs_param *sat;
361 	struct sctp_ipv4addr_param *v4;
362 	struct sctp_ipv6addr_param *v6;
363 	union sctp_addr_param *addr;
364 	struct sctp_adaptation_ind_param *aind;
365 	struct sctp_supported_ext_param *ext;
366 	struct sctp_random_param *random;
367 	struct sctp_chunks_param *chunks;
368 	struct sctp_hmac_algo_param *hmac_algo;
369 	struct sctp_addip_param *addip;
370 };
371 
372 /* RFC 2960.  Section 3.3.5 Heartbeat.
373  *    Heartbeat Information: variable length
374  *    The Sender-specific Heartbeat Info field should normally include
375  *    information about the sender's current time when this HEARTBEAT
376  *    chunk is sent and the destination transport address to which this
377  *    HEARTBEAT is sent (see Section 8.3).
378  */
379 struct sctp_sender_hb_info {
380 	struct sctp_paramhdr param_hdr;
381 	union sctp_addr daddr;
382 	unsigned long sent_at;
383 	__u64 hb_nonce;
384 };
385 
386 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
387 		     gfp_t gfp);
388 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
389 void sctp_stream_free(struct sctp_stream *stream);
390 void sctp_stream_clear(struct sctp_stream *stream);
391 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
392 
393 /* What is the current SSN number for this stream? */
394 #define sctp_ssn_peek(stream, type, sid) \
395 	((stream)->type[sid].ssn)
396 
397 /* Return the next SSN number for this stream.	*/
398 #define sctp_ssn_next(stream, type, sid) \
399 	((stream)->type[sid].ssn++)
400 
401 /* Skip over this ssn and all below. */
402 #define sctp_ssn_skip(stream, type, sid, ssn) \
403 	((stream)->type[sid].ssn = ssn + 1)
404 
405 /*
406  * Pointers to address related SCTP functions.
407  * (i.e. things that depend on the address family.)
408  */
409 struct sctp_af {
410 	int		(*sctp_xmit)	(struct sk_buff *skb,
411 					 struct sctp_transport *);
412 	int		(*setsockopt)	(struct sock *sk,
413 					 int level,
414 					 int optname,
415 					 char __user *optval,
416 					 unsigned int optlen);
417 	int		(*getsockopt)	(struct sock *sk,
418 					 int level,
419 					 int optname,
420 					 char __user *optval,
421 					 int __user *optlen);
422 	int		(*compat_setsockopt)	(struct sock *sk,
423 					 int level,
424 					 int optname,
425 					 char __user *optval,
426 					 unsigned int optlen);
427 	int		(*compat_getsockopt)	(struct sock *sk,
428 					 int level,
429 					 int optname,
430 					 char __user *optval,
431 					 int __user *optlen);
432 	void		(*get_dst)	(struct sctp_transport *t,
433 					 union sctp_addr *saddr,
434 					 struct flowi *fl,
435 					 struct sock *sk);
436 	void		(*get_saddr)	(struct sctp_sock *sk,
437 					 struct sctp_transport *t,
438 					 struct flowi *fl);
439 	void		(*copy_addrlist) (struct list_head *,
440 					  struct net_device *);
441 	int		(*cmp_addr)	(const union sctp_addr *addr1,
442 					 const union sctp_addr *addr2);
443 	void		(*addr_copy)	(union sctp_addr *dst,
444 					 union sctp_addr *src);
445 	void		(*from_skb)	(union sctp_addr *,
446 					 struct sk_buff *skb,
447 					 int saddr);
448 	void		(*from_sk)	(union sctp_addr *,
449 					 struct sock *sk);
450 	void		(*from_addr_param) (union sctp_addr *,
451 					    union sctp_addr_param *,
452 					    __be16 port, int iif);
453 	int		(*to_addr_param) (const union sctp_addr *,
454 					  union sctp_addr_param *);
455 	int		(*addr_valid)	(union sctp_addr *,
456 					 struct sctp_sock *,
457 					 const struct sk_buff *);
458 	enum sctp_scope	(*scope)(union sctp_addr *);
459 	void		(*inaddr_any)	(union sctp_addr *, __be16);
460 	int		(*is_any)	(const union sctp_addr *);
461 	int		(*available)	(union sctp_addr *,
462 					 struct sctp_sock *);
463 	int		(*skb_iif)	(const struct sk_buff *sk);
464 	int		(*is_ce)	(const struct sk_buff *sk);
465 	void		(*seq_dump_addr)(struct seq_file *seq,
466 					 union sctp_addr *addr);
467 	void		(*ecn_capable)(struct sock *sk);
468 	__u16		net_header_len;
469 	int		sockaddr_len;
470 	sa_family_t	sa_family;
471 	struct list_head list;
472 };
473 
474 struct sctp_af *sctp_get_af_specific(sa_family_t);
475 int sctp_register_af(struct sctp_af *);
476 
477 /* Protocol family functions. */
478 struct sctp_pf {
479 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
480 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
481 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
482 	int  (*cmp_addr) (const union sctp_addr *,
483 			  const union sctp_addr *,
484 			  struct sctp_sock *);
485 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
486 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
487 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
488 	struct sock *(*create_accept_sk) (struct sock *sk,
489 					  struct sctp_association *asoc,
490 					  bool kern);
491 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
492 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
493 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
494 	struct sctp_af *af;
495 };
496 
497 
498 /* Structure to track chunk fragments that have been acked, but peer
499  * fragments of the same message have not.
500  */
501 struct sctp_datamsg {
502 	/* Chunks waiting to be submitted to lower layer. */
503 	struct list_head chunks;
504 	/* Reference counting. */
505 	refcount_t refcnt;
506 	/* When is this message no longer interesting to the peer? */
507 	unsigned long expires_at;
508 	/* Did the messenge fail to send? */
509 	int send_error;
510 	u8 send_failed:1,
511 	   can_delay;	    /* should this message be Nagle delayed */
512 };
513 
514 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
515 					    struct sctp_sndrcvinfo *,
516 					    struct iov_iter *);
517 void sctp_datamsg_free(struct sctp_datamsg *);
518 void sctp_datamsg_put(struct sctp_datamsg *);
519 void sctp_chunk_fail(struct sctp_chunk *, int error);
520 int sctp_chunk_abandoned(struct sctp_chunk *);
521 
522 /* RFC2960 1.4 Key Terms
523  *
524  * o Chunk: A unit of information within an SCTP packet, consisting of
525  * a chunk header and chunk-specific content.
526  *
527  * As a matter of convenience, we remember the SCTP common header for
528  * each chunk as well as a few other header pointers...
529  */
530 struct sctp_chunk {
531 	struct list_head list;
532 
533 	refcount_t refcnt;
534 
535 	/* How many times this chunk have been sent, for prsctp RTX policy */
536 	int sent_count;
537 
538 	union {
539 		/* This is our link to the per-transport transmitted list.  */
540 		struct list_head transmitted_list;
541 		/* List in specific stream outq */
542 		struct list_head stream_list;
543 	};
544 
545 	/* This field is used by chunks that hold fragmented data.
546 	 * For the first fragment this is the list that holds the rest of
547 	 * fragments. For the remaining fragments, this is the link to the
548 	 * frag_list maintained in the first fragment.
549 	 */
550 	struct list_head frag_list;
551 
552 	/* This points to the sk_buff containing the actual data.  */
553 	struct sk_buff *skb;
554 
555 	/* In case of GSO packets, this will store the head one */
556 	struct sk_buff *head_skb;
557 
558 	/* These are the SCTP headers by reverse order in a packet.
559 	 * Note that some of these may happen more than once.  In that
560 	 * case, we point at the "current" one, whatever that means
561 	 * for that level of header.
562 	 */
563 
564 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
565 	union sctp_params param_hdr;
566 	union {
567 		__u8 *v;
568 		struct sctp_datahdr *data_hdr;
569 		struct sctp_inithdr *init_hdr;
570 		struct sctp_sackhdr *sack_hdr;
571 		struct sctp_heartbeathdr *hb_hdr;
572 		struct sctp_sender_hb_info *hbs_hdr;
573 		struct sctp_shutdownhdr *shutdown_hdr;
574 		struct sctp_signed_cookie *cookie_hdr;
575 		struct sctp_ecnehdr *ecne_hdr;
576 		struct sctp_cwrhdr *ecn_cwr_hdr;
577 		struct sctp_errhdr *err_hdr;
578 		struct sctp_addiphdr *addip_hdr;
579 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
580 		struct sctp_authhdr *auth_hdr;
581 	} subh;
582 
583 	__u8 *chunk_end;
584 
585 	struct sctp_chunkhdr *chunk_hdr;
586 	struct sctphdr *sctp_hdr;
587 
588 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
589 	struct sctp_sndrcvinfo sinfo;
590 
591 	/* Which association does this belong to?  */
592 	struct sctp_association *asoc;
593 
594 	/* What endpoint received this chunk? */
595 	struct sctp_ep_common *rcvr;
596 
597 	/* We fill this in if we are calculating RTT. */
598 	unsigned long sent_at;
599 
600 	/* What is the origin IP address for this chunk?  */
601 	union sctp_addr source;
602 	/* Destination address for this chunk. */
603 	union sctp_addr dest;
604 
605 	/* For outbound message, track all fragments for SEND_FAILED. */
606 	struct sctp_datamsg *msg;
607 
608 	/* For an inbound chunk, this tells us where it came from.
609 	 * For an outbound chunk, it tells us where we'd like it to
610 	 * go.	It is NULL if we have no preference.
611 	 */
612 	struct sctp_transport *transport;
613 
614 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
615 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
616 	 * spec violates the principle premis that all chunks are processed
617 	 * in order.
618 	 */
619 	struct sk_buff *auth_chunk;
620 
621 #define SCTP_CAN_FRTX 0x0
622 #define SCTP_NEED_FRTX 0x1
623 #define SCTP_DONT_FRTX 0x2
624 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
625 		has_tsn:1,		/* Does this chunk have a TSN yet? */
626 		has_ssn:1,		/* Does this chunk have a SSN yet? */
627 		singleton:1,		/* Only chunk in the packet? */
628 		end_of_packet:1,	/* Last chunk in the packet? */
629 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
630 		pdiscard:1,		/* Discard the whole packet now? */
631 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
632 		data_accepted:1,	/* At least 1 chunk accepted */
633 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
634 		has_asconf:1,		/* IN: have seen an asconf before */
635 		tsn_missing_report:2,	/* Data chunk missing counter. */
636 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
637 };
638 
639 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
640 void sctp_chunk_hold(struct sctp_chunk *);
641 void sctp_chunk_put(struct sctp_chunk *);
642 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
643 			  struct iov_iter *from);
644 void sctp_chunk_free(struct sctp_chunk *);
645 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
646 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
647 				 const struct sctp_association *,
648 				 struct sock *, gfp_t gfp);
649 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
650 		     union sctp_addr *);
651 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
652 
653 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
654 {
655 	return ntohs(ch->subh.data_hdr->stream);
656 }
657 
658 enum {
659 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
660 	SCTP_ADDR_SRC,		/* address can be used as source */
661 	SCTP_ADDR_DEL,		/* address about to be deleted */
662 };
663 
664 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
665 struct sctp_sockaddr_entry {
666 	struct list_head list;
667 	struct rcu_head	rcu;
668 	union sctp_addr a;
669 	__u8 state;
670 	__u8 valid;
671 };
672 
673 #define SCTP_ADDRESS_TICK_DELAY	500
674 
675 /* This structure holds lists of chunks as we are assembling for
676  * transmission.
677  */
678 struct sctp_packet {
679 	/* These are the SCTP header values (host order) for the packet. */
680 	__u16 source_port;
681 	__u16 destination_port;
682 	__u32 vtag;
683 
684 	/* This contains the payload chunks.  */
685 	struct list_head chunk_list;
686 
687 	/* This is the overhead of the sctp and ip headers. */
688 	size_t overhead;
689 	/* This is the total size of all chunks INCLUDING padding.  */
690 	size_t size;
691 	/* This is the maximum size this packet may have */
692 	size_t max_size;
693 
694 	/* The packet is destined for this transport address.
695 	 * The function we finally use to pass down to the next lower
696 	 * layer lives in the transport structure.
697 	 */
698 	struct sctp_transport *transport;
699 
700 	/* pointer to the auth chunk for this packet */
701 	struct sctp_chunk *auth;
702 
703 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
704 	    has_sack:1,		/* This packet contains a SACK chunk. */
705 	    has_auth:1,		/* This packet contains an AUTH chunk */
706 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
707 	    ipfragok:1;		/* So let ip fragment this packet */
708 };
709 
710 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
711 		      __u16 sport, __u16 dport);
712 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
713 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
714 					  struct sctp_chunk *chunk,
715 					  int one_packet, gfp_t gfp);
716 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
717 					struct sctp_chunk *chunk);
718 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
719 void sctp_packet_free(struct sctp_packet *);
720 
721 static inline int sctp_packet_empty(struct sctp_packet *packet)
722 {
723 	return packet->size == packet->overhead;
724 }
725 
726 /* This represents a remote transport address.
727  * For local transport addresses, we just use union sctp_addr.
728  *
729  * RFC2960 Section 1.4 Key Terms
730  *
731  *   o	Transport address:  A Transport Address is traditionally defined
732  *	by Network Layer address, Transport Layer protocol and Transport
733  *	Layer port number.  In the case of SCTP running over IP, a
734  *	transport address is defined by the combination of an IP address
735  *	and an SCTP port number (where SCTP is the Transport protocol).
736  *
737  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
738  *
739  *   o	The sender keeps a separate congestion control parameter set for
740  *	each of the destination addresses it can send to (not each
741  *	source-destination pair but for each destination).  The parameters
742  *	should decay if the address is not used for a long enough time
743  *	period.
744  *
745  */
746 struct sctp_transport {
747 	/* A list of transports. */
748 	struct list_head transports;
749 	struct rhlist_head node;
750 
751 	/* Reference counting. */
752 	refcount_t refcnt;
753 		/* RTO-Pending : A flag used to track if one of the DATA
754 		 *		chunks sent to this address is currently being
755 		 *		used to compute a RTT. If this flag is 0,
756 		 *		the next DATA chunk sent to this destination
757 		 *		should be used to compute a RTT and this flag
758 		 *		should be set. Every time the RTT
759 		 *		calculation completes (i.e. the DATA chunk
760 		 *		is SACK'd) clear this flag.
761 		 */
762 	__u32	rto_pending:1,
763 
764 		/*
765 		 * hb_sent : a flag that signals that we have a pending
766 		 * heartbeat.
767 		 */
768 		hb_sent:1,
769 
770 		/* Is the Path MTU update pending on this tranport */
771 		pmtu_pending:1,
772 
773 		dst_pending_confirm:1,	/* need to confirm neighbour */
774 
775 		/* Has this transport moved the ctsn since we last sacked */
776 		sack_generation:1;
777 	u32 dst_cookie;
778 
779 	struct flowi fl;
780 
781 	/* This is the peer's IP address and port. */
782 	union sctp_addr ipaddr;
783 
784 	/* These are the functions we call to handle LLP stuff.	 */
785 	struct sctp_af *af_specific;
786 
787 	/* Which association do we belong to?  */
788 	struct sctp_association *asoc;
789 
790 	/* RFC2960
791 	 *
792 	 * 12.3 Per Transport Address Data
793 	 *
794 	 * For each destination transport address in the peer's
795 	 * address list derived from the INIT or INIT ACK chunk, a
796 	 * number of data elements needs to be maintained including:
797 	 */
798 	/* RTO	       : The current retransmission timeout value.  */
799 	unsigned long rto;
800 
801 	__u32 rtt;		/* This is the most recent RTT.	 */
802 
803 	/* RTTVAR      : The current RTT variation.  */
804 	__u32 rttvar;
805 
806 	/* SRTT	       : The current smoothed round trip time.	*/
807 	__u32 srtt;
808 
809 	/*
810 	 * These are the congestion stats.
811 	 */
812 	/* cwnd	       : The current congestion window.	 */
813 	__u32 cwnd;		  /* This is the actual cwnd.  */
814 
815 	/* ssthresh    : The current slow start threshold value.  */
816 	__u32 ssthresh;
817 
818 	/* partial     : The tracking method for increase of cwnd when in
819 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
820 	 */
821 	__u32 partial_bytes_acked;
822 
823 	/* Data that has been sent, but not acknowledged. */
824 	__u32 flight_size;
825 
826 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
827 
828 	/* Destination */
829 	struct dst_entry *dst;
830 	/* Source address. */
831 	union sctp_addr saddr;
832 
833 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
834 	 * the destination address every heartbeat interval.
835 	 */
836 	unsigned long hbinterval;
837 
838 	/* SACK delay timeout */
839 	unsigned long sackdelay;
840 	__u32 sackfreq;
841 
842 	/* When was the last time that we heard from this transport? We use
843 	 * this to pick new active and retran paths.
844 	 */
845 	ktime_t last_time_heard;
846 
847 	/* When was the last time that we sent a chunk using this
848 	 * transport? We use this to check for idle transports
849 	 */
850 	unsigned long last_time_sent;
851 
852 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
853 	 * indication based on ECNE chunk.
854 	 */
855 	unsigned long last_time_ecne_reduced;
856 
857 	/* This is the max_retrans value for the transport and will
858 	 * be initialized from the assocs value.  This can be changed
859 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
860 	 */
861 	__u16 pathmaxrxt;
862 
863 	/* This is the partially failed retrans value for the transport
864 	 * and will be initialized from the assocs value.  This can be changed
865 	 * using the SCTP_PEER_ADDR_THLDS socket option
866 	 */
867 	int pf_retrans;
868 	/* PMTU	      : The current known path MTU.  */
869 	__u32 pathmtu;
870 
871 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
872 	__u32 param_flags;
873 
874 	/* The number of times INIT has been sent on this transport. */
875 	int init_sent_count;
876 
877 	/* state       : The current state of this destination,
878 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
879 	 */
880 	int state;
881 
882 	/* These are the error stats for this destination.  */
883 
884 	/* Error count : The current error count for this destination.	*/
885 	unsigned short error_count;
886 
887 	/* Per	       : A timer used by each destination.
888 	 * Destination :
889 	 * Timer       :
890 	 *
891 	 * [Everywhere else in the text this is called T3-rtx. -ed]
892 	 */
893 	struct timer_list T3_rtx_timer;
894 
895 	/* Heartbeat timer is per destination. */
896 	struct timer_list hb_timer;
897 
898 	/* Timer to handle ICMP proto unreachable envets */
899 	struct timer_list proto_unreach_timer;
900 
901 	/* Timer to handler reconf chunk rtx */
902 	struct timer_list reconf_timer;
903 
904 	/* Since we're using per-destination retransmission timers
905 	 * (see above), we're also using per-destination "transmitted"
906 	 * queues.  This probably ought to be a private struct
907 	 * accessible only within the outqueue, but it's not, yet.
908 	 */
909 	struct list_head transmitted;
910 
911 	/* We build bundle-able packets for this transport here.  */
912 	struct sctp_packet packet;
913 
914 	/* This is the list of transports that have chunks to send.  */
915 	struct list_head send_ready;
916 
917 	/* State information saved for SFR_CACC algorithm. The key
918 	 * idea in SFR_CACC is to maintain state at the sender on a
919 	 * per-destination basis when a changeover happens.
920 	 *	char changeover_active;
921 	 *	char cycling_changeover;
922 	 *	__u32 next_tsn_at_change;
923 	 *	char cacc_saw_newack;
924 	 */
925 	struct {
926 		/* An unsigned integer, which stores the next TSN to be
927 		 * used by the sender, at the moment of changeover.
928 		 */
929 		__u32 next_tsn_at_change;
930 
931 		/* A flag which indicates the occurrence of a changeover */
932 		char changeover_active;
933 
934 		/* A flag which indicates whether the change of primary is
935 		 * the first switch to this destination address during an
936 		 * active switch.
937 		 */
938 		char cycling_changeover;
939 
940 		/* A temporary flag, which is used during the processing of
941 		 * a SACK to estimate the causative TSN(s)'s group.
942 		 */
943 		char cacc_saw_newack;
944 	} cacc;
945 
946 	/* 64-bit random number sent with heartbeat. */
947 	__u64 hb_nonce;
948 
949 	struct rcu_head rcu;
950 };
951 
952 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
953 					  gfp_t);
954 void sctp_transport_set_owner(struct sctp_transport *,
955 			      struct sctp_association *);
956 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
957 			  struct sctp_sock *);
958 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
959 void sctp_transport_free(struct sctp_transport *);
960 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
961 void sctp_transport_reset_hb_timer(struct sctp_transport *);
962 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
963 int sctp_transport_hold(struct sctp_transport *);
964 void sctp_transport_put(struct sctp_transport *);
965 void sctp_transport_update_rto(struct sctp_transport *, __u32);
966 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
967 void sctp_transport_lower_cwnd(struct sctp_transport *t,
968 			       enum sctp_lower_cwnd reason);
969 void sctp_transport_burst_limited(struct sctp_transport *);
970 void sctp_transport_burst_reset(struct sctp_transport *);
971 unsigned long sctp_transport_timeout(struct sctp_transport *);
972 void sctp_transport_reset(struct sctp_transport *t);
973 void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
974 void sctp_transport_immediate_rtx(struct sctp_transport *);
975 void sctp_transport_dst_release(struct sctp_transport *t);
976 void sctp_transport_dst_confirm(struct sctp_transport *t);
977 
978 
979 /* This is the structure we use to queue packets as they come into
980  * SCTP.  We write packets to it and read chunks from it.
981  */
982 struct sctp_inq {
983 	/* This is actually a queue of sctp_chunk each
984 	 * containing a partially decoded packet.
985 	 */
986 	struct list_head in_chunk_list;
987 	/* This is the packet which is currently off the in queue and is
988 	 * being worked on through the inbound chunk processing.
989 	 */
990 	struct sctp_chunk *in_progress;
991 
992 	/* This is the delayed task to finish delivering inbound
993 	 * messages.
994 	 */
995 	struct work_struct immediate;
996 };
997 
998 void sctp_inq_init(struct sctp_inq *);
999 void sctp_inq_free(struct sctp_inq *);
1000 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1001 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1002 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1003 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1004 
1005 /* This is the structure we use to hold outbound chunks.  You push
1006  * chunks in and they automatically pop out the other end as bundled
1007  * packets (it calls (*output_handler)()).
1008  *
1009  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1010  * and 8.2 of the v13 draft.
1011  *
1012  * It handles retransmissions.	The connection to the timeout portion
1013  * of the state machine is through sctp_..._timeout() and timeout_handler.
1014  *
1015  * If you feed it SACKs, it will eat them.
1016  *
1017  * If you give it big chunks, it will fragment them.
1018  *
1019  * It assigns TSN's to data chunks.  This happens at the last possible
1020  * instant before transmission.
1021  *
1022  * When free()'d, it empties itself out via output_handler().
1023  */
1024 struct sctp_outq {
1025 	struct sctp_association *asoc;
1026 
1027 	/* Data pending that has never been transmitted.  */
1028 	struct list_head out_chunk_list;
1029 
1030 	/* Stream scheduler being used */
1031 	struct sctp_sched_ops *sched;
1032 
1033 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1034 
1035 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1036 	unsigned int error;
1037 
1038 	/* These are control chunks we want to send.  */
1039 	struct list_head control_chunk_list;
1040 
1041 	/* These are chunks that have been sacked but are above the
1042 	 * CTSN, or cumulative tsn ack point.
1043 	 */
1044 	struct list_head sacked;
1045 
1046 	/* Put chunks on this list to schedule them for
1047 	 * retransmission.
1048 	 */
1049 	struct list_head retransmit;
1050 
1051 	/* Put chunks on this list to save them for FWD TSN processing as
1052 	 * they were abandoned.
1053 	 */
1054 	struct list_head abandoned;
1055 
1056 	/* How many unackd bytes do we have in-flight?	*/
1057 	__u32 outstanding_bytes;
1058 
1059 	/* Are we doing fast-rtx on this queue */
1060 	char fast_rtx;
1061 
1062 	/* Corked? */
1063 	char cork;
1064 };
1065 
1066 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1067 void sctp_outq_teardown(struct sctp_outq *);
1068 void sctp_outq_free(struct sctp_outq*);
1069 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1070 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1071 int sctp_outq_is_empty(const struct sctp_outq *);
1072 void sctp_outq_restart(struct sctp_outq *);
1073 
1074 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1075 		     enum sctp_retransmit_reason reason);
1076 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1077 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1078 void sctp_prsctp_prune(struct sctp_association *asoc,
1079 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1080 /* Uncork and flush an outqueue.  */
1081 static inline void sctp_outq_cork(struct sctp_outq *q)
1082 {
1083 	q->cork = 1;
1084 }
1085 
1086 /* SCTP skb control block.
1087  * sctp_input_cb is currently used on rx and sock rx queue
1088  */
1089 struct sctp_input_cb {
1090 	union {
1091 		struct inet_skb_parm	h4;
1092 #if IS_ENABLED(CONFIG_IPV6)
1093 		struct inet6_skb_parm	h6;
1094 #endif
1095 	} header;
1096 	struct sctp_chunk *chunk;
1097 	struct sctp_af *af;
1098 };
1099 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1100 
1101 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1102 {
1103 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1104 
1105 	return chunk->head_skb ? : skb;
1106 }
1107 
1108 /* These bind address data fields common between endpoints and associations */
1109 struct sctp_bind_addr {
1110 
1111 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1112 	 *
1113 	 * SCTP Port:	The local SCTP port number the endpoint is
1114 	 *		bound to.
1115 	 */
1116 	__u16 port;
1117 
1118 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1119 	 *
1120 	 * Address List: The list of IP addresses that this instance
1121 	 *	has bound.  This information is passed to one's
1122 	 *	peer(s) in INIT and INIT ACK chunks.
1123 	 */
1124 	struct list_head address_list;
1125 };
1126 
1127 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1128 void sctp_bind_addr_free(struct sctp_bind_addr *);
1129 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1130 			const struct sctp_bind_addr *src,
1131 			enum sctp_scope scope, gfp_t gfp,
1132 			int flags);
1133 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1134 			const struct sctp_bind_addr *src,
1135 			gfp_t gfp);
1136 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1137 		       int new_size, __u8 addr_state, gfp_t gfp);
1138 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1139 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1140 			 struct sctp_sock *);
1141 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1142 			 struct sctp_sock *, struct sctp_sock *);
1143 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1144 			 const union sctp_addr *addr);
1145 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1146 					const union sctp_addr	*addrs,
1147 					int			addrcnt,
1148 					struct sctp_sock	*opt);
1149 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1150 					 int *addrs_len,
1151 					 gfp_t gfp);
1152 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1153 			   __u16 port, gfp_t gfp);
1154 
1155 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1156 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1157 		  const enum sctp_scope scope);
1158 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1159 int sctp_is_ep_boundall(struct sock *sk);
1160 
1161 
1162 /* What type of endpoint?  */
1163 enum sctp_endpoint_type {
1164 	SCTP_EP_TYPE_SOCKET,
1165 	SCTP_EP_TYPE_ASSOCIATION,
1166 };
1167 
1168 /*
1169  * A common base class to bridge the implmentation view of a
1170  * socket (usually listening) endpoint versus an association's
1171  * local endpoint.
1172  * This common structure is useful for several purposes:
1173  *   1) Common interface for lookup routines.
1174  *	a) Subfunctions work for either endpoint or association
1175  *	b) Single interface to lookup allows hiding the lookup lock rather
1176  *	   than acquiring it externally.
1177  *   2) Common interface for the inbound chunk handling/state machine.
1178  *   3) Common object handling routines for reference counting, etc.
1179  *   4) Disentangle association lookup from endpoint lookup, where we
1180  *	do not have to find our endpoint to find our association.
1181  *
1182  */
1183 
1184 struct sctp_ep_common {
1185 	/* Fields to help us manage our entries in the hash tables. */
1186 	struct hlist_node node;
1187 	int hashent;
1188 
1189 	/* Runtime type information.  What kind of endpoint is this? */
1190 	enum sctp_endpoint_type type;
1191 
1192 	/* Some fields to help us manage this object.
1193 	 *   refcnt   - Reference count access to this object.
1194 	 *   dead     - Do not attempt to use this object.
1195 	 */
1196 	refcount_t    refcnt;
1197 	bool	    dead;
1198 
1199 	/* What socket does this endpoint belong to?  */
1200 	struct sock *sk;
1201 
1202 	/* This is where we receive inbound chunks.  */
1203 	struct sctp_inq	  inqueue;
1204 
1205 	/* This substructure includes the defining parameters of the
1206 	 * endpoint:
1207 	 * bind_addr.port is our shared port number.
1208 	 * bind_addr.address_list is our set of local IP addresses.
1209 	 */
1210 	struct sctp_bind_addr bind_addr;
1211 };
1212 
1213 
1214 /* RFC Section 1.4 Key Terms
1215  *
1216  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1217  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1218  *   combination of a set of eligible destination transport addresses to
1219  *   which SCTP packets can be sent and a set of eligible source
1220  *   transport addresses from which SCTP packets can be received.
1221  *   All transport addresses used by an SCTP endpoint must use the
1222  *   same port number, but can use multiple IP addresses. A transport
1223  *   address used by an SCTP endpoint must not be used by another
1224  *   SCTP endpoint. In other words, a transport address is unique
1225  *   to an SCTP endpoint.
1226  *
1227  * From an implementation perspective, each socket has one of these.
1228  * A TCP-style socket will have exactly one association on one of
1229  * these.  An UDP-style socket will have multiple associations hanging
1230  * off one of these.
1231  */
1232 
1233 struct sctp_endpoint {
1234 	/* Common substructure for endpoint and association. */
1235 	struct sctp_ep_common base;
1236 
1237 	/* Associations: A list of current associations and mappings
1238 	 *	      to the data consumers for each association. This
1239 	 *	      may be in the form of a hash table or other
1240 	 *	      implementation dependent structure. The data
1241 	 *	      consumers may be process identification
1242 	 *	      information such as file descriptors, named pipe
1243 	 *	      pointer, or table pointers dependent on how SCTP
1244 	 *	      is implemented.
1245 	 */
1246 	/* This is really a list of struct sctp_association entries. */
1247 	struct list_head asocs;
1248 
1249 	/* Secret Key: A secret key used by this endpoint to compute
1250 	 *	      the MAC.	This SHOULD be a cryptographic quality
1251 	 *	      random number with a sufficient length.
1252 	 *	      Discussion in [RFC1750] can be helpful in
1253 	 *	      selection of the key.
1254 	 */
1255 	__u8 secret_key[SCTP_SECRET_SIZE];
1256 
1257  	/* digest:  This is a digest of the sctp cookie.  This field is
1258  	 * 	    only used on the receive path when we try to validate
1259  	 * 	    that the cookie has not been tampered with.  We put
1260  	 * 	    this here so we pre-allocate this once and can re-use
1261  	 * 	    on every receive.
1262  	 */
1263  	__u8 *digest;
1264 
1265 	/* sendbuf acct. policy.	*/
1266 	__u32 sndbuf_policy;
1267 
1268 	/* rcvbuf acct. policy.	*/
1269 	__u32 rcvbuf_policy;
1270 
1271 	/* SCTP AUTH: array of the HMACs that will be allocated
1272 	 * we need this per association so that we don't serialize
1273 	 */
1274 	struct crypto_shash **auth_hmacs;
1275 
1276 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1277 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1278 
1279 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1280 	struct sctp_chunks_param *auth_chunk_list;
1281 
1282 	/* SCTP-AUTH: endpoint shared keys */
1283 	struct list_head endpoint_shared_keys;
1284 	__u16 active_key_id;
1285 	__u8  auth_enable:1,
1286 	      prsctp_enable:1,
1287 	      reconf_enable:1;
1288 
1289 	__u8  strreset_enable;
1290 };
1291 
1292 /* Recover the outter endpoint structure. */
1293 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1294 {
1295 	struct sctp_endpoint *ep;
1296 
1297 	ep = container_of(base, struct sctp_endpoint, base);
1298 	return ep;
1299 }
1300 
1301 /* These are function signatures for manipulating endpoints.  */
1302 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1303 void sctp_endpoint_free(struct sctp_endpoint *);
1304 void sctp_endpoint_put(struct sctp_endpoint *);
1305 void sctp_endpoint_hold(struct sctp_endpoint *);
1306 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1307 struct sctp_association *sctp_endpoint_lookup_assoc(
1308 	const struct sctp_endpoint *ep,
1309 	const union sctp_addr *paddr,
1310 	struct sctp_transport **);
1311 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1312 				const union sctp_addr *);
1313 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1314 					struct net *, const union sctp_addr *);
1315 int sctp_has_association(struct net *net, const union sctp_addr *laddr,
1316 			 const union sctp_addr *paddr);
1317 
1318 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1319 		     const struct sctp_association *asoc,
1320 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1321 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1322 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1323 		      const union sctp_addr *peer,
1324 		      struct sctp_init_chunk *init, gfp_t gfp);
1325 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1326 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1327 
1328 struct sctp_inithdr_host {
1329 	__u32 init_tag;
1330 	__u32 a_rwnd;
1331 	__u16 num_outbound_streams;
1332 	__u16 num_inbound_streams;
1333 	__u32 initial_tsn;
1334 };
1335 
1336 struct sctp_stream_priorities {
1337 	/* List of priorities scheduled */
1338 	struct list_head prio_sched;
1339 	/* List of streams scheduled */
1340 	struct list_head active;
1341 	/* The next stream stream in line */
1342 	struct sctp_stream_out_ext *next;
1343 	__u16 prio;
1344 };
1345 
1346 struct sctp_stream_out_ext {
1347 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1348 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1349 	struct list_head outq; /* chunks enqueued by this stream */
1350 	union {
1351 		struct {
1352 			/* Scheduled streams list */
1353 			struct list_head prio_list;
1354 			struct sctp_stream_priorities *prio_head;
1355 		};
1356 		/* Fields used by RR scheduler */
1357 		struct {
1358 			struct list_head rr_list;
1359 		};
1360 	};
1361 };
1362 
1363 struct sctp_stream_out {
1364 	__u16	ssn;
1365 	__u8	state;
1366 	struct sctp_stream_out_ext *ext;
1367 };
1368 
1369 struct sctp_stream_in {
1370 	__u16	ssn;
1371 };
1372 
1373 struct sctp_stream {
1374 	struct sctp_stream_out *out;
1375 	struct sctp_stream_in *in;
1376 	__u16 outcnt;
1377 	__u16 incnt;
1378 	/* Current stream being sent, if any */
1379 	struct sctp_stream_out *out_curr;
1380 	union {
1381 		/* Fields used by priority scheduler */
1382 		struct {
1383 			/* List of priorities scheduled */
1384 			struct list_head prio_list;
1385 		};
1386 		/* Fields used by RR scheduler */
1387 		struct {
1388 			/* List of streams scheduled */
1389 			struct list_head rr_list;
1390 			/* The next stream stream in line */
1391 			struct sctp_stream_out_ext *rr_next;
1392 		};
1393 	};
1394 };
1395 
1396 #define SCTP_STREAM_CLOSED		0x00
1397 #define SCTP_STREAM_OPEN		0x01
1398 
1399 /* SCTP_GET_ASSOC_STATS counters */
1400 struct sctp_priv_assoc_stats {
1401 	/* Maximum observed rto in the association during subsequent
1402 	 * observations. Value is set to 0 if no RTO measurement took place
1403 	 * The transport where the max_rto was observed is returned in
1404 	 * obs_rto_ipaddr
1405 	 */
1406 	struct sockaddr_storage obs_rto_ipaddr;
1407 	__u64 max_obs_rto;
1408 	/* Total In and Out SACKs received and sent */
1409 	__u64 isacks;
1410 	__u64 osacks;
1411 	/* Total In and Out packets received and sent */
1412 	__u64 opackets;
1413 	__u64 ipackets;
1414 	/* Total retransmitted chunks */
1415 	__u64 rtxchunks;
1416 	/* TSN received > next expected */
1417 	__u64 outofseqtsns;
1418 	/* Duplicate Chunks received */
1419 	__u64 idupchunks;
1420 	/* Gap Ack Blocks received */
1421 	__u64 gapcnt;
1422 	/* Unordered data chunks sent and received */
1423 	__u64 ouodchunks;
1424 	__u64 iuodchunks;
1425 	/* Ordered data chunks sent and received */
1426 	__u64 oodchunks;
1427 	__u64 iodchunks;
1428 	/* Control chunks sent and received */
1429 	__u64 octrlchunks;
1430 	__u64 ictrlchunks;
1431 };
1432 
1433 /* RFC2960
1434  *
1435  * 12. Recommended Transmission Control Block (TCB) Parameters
1436  *
1437  * This section details a recommended set of parameters that should
1438  * be contained within the TCB for an implementation. This section is
1439  * for illustrative purposes and should not be deemed as requirements
1440  * on an implementation or as an exhaustive list of all parameters
1441  * inside an SCTP TCB. Each implementation may need its own additional
1442  * parameters for optimization.
1443  */
1444 
1445 
1446 /* Here we have information about each individual association. */
1447 struct sctp_association {
1448 
1449 	/* A base structure common to endpoint and association.
1450 	 * In this context, it represents the associations's view
1451 	 * of the local endpoint of the association.
1452 	 */
1453 	struct sctp_ep_common base;
1454 
1455 	/* Associations on the same socket. */
1456 	struct list_head asocs;
1457 
1458 	/* association id. */
1459 	sctp_assoc_t assoc_id;
1460 
1461 	/* This is our parent endpoint.	 */
1462 	struct sctp_endpoint *ep;
1463 
1464 	/* These are those association elements needed in the cookie.  */
1465 	struct sctp_cookie c;
1466 
1467 	/* This is all information about our peer.  */
1468 	struct {
1469 		/* transport_addr_list
1470 		 *
1471 		 * Peer	       : A list of SCTP transport addresses that the
1472 		 * Transport   : peer is bound to. This information is derived
1473 		 * Address     : from the INIT or INIT ACK and is used to
1474 		 * List	       : associate an inbound packet with a given
1475 		 *	       : association. Normally this information is
1476 		 *	       : hashed or keyed for quick lookup and access
1477 		 *	       : of the TCB.
1478 		 *	       : The list is also initialized with the list
1479 		 *	       : of addresses passed with the sctp_connectx()
1480 		 *	       : call.
1481 		 *
1482 		 * It is a list of SCTP_transport's.
1483 		 */
1484 		struct list_head transport_addr_list;
1485 
1486 		/* rwnd
1487 		 *
1488 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1489 		 */
1490 		__u32 rwnd;
1491 
1492 		/* transport_count
1493 		 *
1494 		 * Peer        : A count of the number of peer addresses
1495 		 * Transport   : in the Peer Transport Address List.
1496 		 * Address     :
1497 		 * Count       :
1498 		 */
1499 		__u16 transport_count;
1500 
1501 		/* port
1502 		 *   The transport layer port number.
1503 		 */
1504 		__u16 port;
1505 
1506 		/* primary_path
1507 		 *
1508 		 * Primary     : This is the current primary destination
1509 		 * Path	       : transport address of the peer endpoint.  It
1510 		 *	       : may also specify a source transport address
1511 		 *	       : on this endpoint.
1512 		 *
1513 		 * All of these paths live on transport_addr_list.
1514 		 *
1515 		 * At the bakeoffs, we discovered that the intent of
1516 		 * primaryPath is that it only changes when the ULP
1517 		 * asks to have it changed.  We add the activePath to
1518 		 * designate the connection we are currently using to
1519 		 * transmit new data and most control chunks.
1520 		 */
1521 		struct sctp_transport *primary_path;
1522 
1523 		/* Cache the primary path address here, when we
1524 		 * need a an address for msg_name.
1525 		 */
1526 		union sctp_addr primary_addr;
1527 
1528 		/* active_path
1529 		 *   The path that we are currently using to
1530 		 *   transmit new data and most control chunks.
1531 		 */
1532 		struct sctp_transport *active_path;
1533 
1534 		/* retran_path
1535 		 *
1536 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1537 		 * ...
1538 		 * Furthermore, when its peer is multi-homed, an
1539 		 * endpoint SHOULD try to retransmit a chunk to an
1540 		 * active destination transport address that is
1541 		 * different from the last destination address to
1542 		 * which the DATA chunk was sent.
1543 		 */
1544 		struct sctp_transport *retran_path;
1545 
1546 		/* Pointer to last transport I have sent on.  */
1547 		struct sctp_transport *last_sent_to;
1548 
1549 		/* This is the last transport I have received DATA on.	*/
1550 		struct sctp_transport *last_data_from;
1551 
1552 		/*
1553 		 * Mapping  An array of bits or bytes indicating which out of
1554 		 * Array    order TSN's have been received (relative to the
1555 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1556 		 *	    order packets have been received, this array
1557 		 *	    will be set to all zero. This structure may be
1558 		 *	    in the form of a circular buffer or bit array.
1559 		 *
1560 		 * Last Rcvd   : This is the last TSN received in
1561 		 * TSN	       : sequence. This value is set initially by
1562 		 *	       : taking the peer's Initial TSN, received in
1563 		 *	       : the INIT or INIT ACK chunk, and subtracting
1564 		 *	       : one from it.
1565 		 *
1566 		 * Throughout most of the specification this is called the
1567 		 * "Cumulative TSN ACK Point".	In this case, we
1568 		 * ignore the advice in 12.2 in favour of the term
1569 		 * used in the bulk of the text.  This value is hidden
1570 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1571 		 */
1572 		struct sctp_tsnmap tsn_map;
1573 
1574 		/* This mask is used to disable sending the ASCONF chunk
1575 		 * with specified parameter to peer.
1576 		 */
1577 		__be16 addip_disabled_mask;
1578 
1579 		/* These are capabilities which our peer advertised.  */
1580 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1581 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1582 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1583 			hostname_address:1, /* Peer understands DNS addresses? */
1584 			asconf_capable:1,   /* Does peer support ADDIP? */
1585 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1586 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1587 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1588 
1589 		/* sack_needed : This flag indicates if the next received
1590 		 *             : packet is to be responded to with a
1591 		 *             : SACK. This is initialized to 0.  When a packet
1592 		 *             : is received sack_cnt is incremented. If this value
1593 		 *             : reaches 2 or more, a SACK is sent and the
1594 		 *             : value is reset to 0. Note: This is used only
1595 		 *             : when no DATA chunks are received out of
1596 		 *             : order.  When DATA chunks are out of order,
1597 		 *             : SACK's are not delayed (see Section 6).
1598 		 */
1599 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1600 			sack_generation:1,
1601 			zero_window_announced:1;
1602 		__u32	sack_cnt;
1603 
1604 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1605 
1606 		struct sctp_inithdr_host i;
1607 		void *cookie;
1608 		int cookie_len;
1609 
1610 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1611 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1612 		 * Initial TSN Value minus 1
1613 		 */
1614 		__u32 addip_serial;
1615 
1616 		/* SCTP-AUTH: We need to know pears random number, hmac list
1617 		 * and authenticated chunk list.  All that is part of the
1618 		 * cookie and these are just pointers to those locations
1619 		 */
1620 		struct sctp_random_param *peer_random;
1621 		struct sctp_chunks_param *peer_chunks;
1622 		struct sctp_hmac_algo_param *peer_hmacs;
1623 	} peer;
1624 
1625 	/* State       : A state variable indicating what state the
1626 	 *	       : association is in, i.e. COOKIE-WAIT,
1627 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1628 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1629 	 *
1630 	 *		Note: No "CLOSED" state is illustrated since if a
1631 	 *		association is "CLOSED" its TCB SHOULD be removed.
1632 	 *
1633 	 *		In this implementation we DO have a CLOSED
1634 	 *		state which is used during initiation and shutdown.
1635 	 *
1636 	 *		State takes values from SCTP_STATE_*.
1637 	 */
1638 	enum sctp_state state;
1639 
1640 	/* Overall     : The overall association error count.
1641 	 * Error Count : [Clear this any time I get something.]
1642 	 */
1643 	int overall_error_count;
1644 
1645 	/* The cookie life I award for any cookie.  */
1646 	ktime_t cookie_life;
1647 
1648 	/* These are the association's initial, max, and min RTO values.
1649 	 * These values will be initialized by system defaults, but can
1650 	 * be modified via the SCTP_RTOINFO socket option.
1651 	 */
1652 	unsigned long rto_initial;
1653 	unsigned long rto_max;
1654 	unsigned long rto_min;
1655 
1656 	/* Maximum number of new data packets that can be sent in a burst.  */
1657 	int max_burst;
1658 
1659 	/* This is the max_retrans value for the association.  This value will
1660 	 * be initialized initialized from system defaults, but can be
1661 	 * modified by the SCTP_ASSOCINFO socket option.
1662 	 */
1663 	int max_retrans;
1664 
1665 	/* This is the partially failed retrans value for the transport
1666 	 * and will be initialized from the assocs value.  This can be
1667 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1668 	 */
1669 	int pf_retrans;
1670 
1671 	/* Maximum number of times the endpoint will retransmit INIT  */
1672 	__u16 max_init_attempts;
1673 
1674 	/* How many times have we resent an INIT? */
1675 	__u16 init_retries;
1676 
1677 	/* The largest timeout or RTO value to use in attempting an INIT */
1678 	unsigned long max_init_timeo;
1679 
1680 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1681 	 * the destination address every heartbeat interval. This value
1682 	 * will be inherited by all new transports.
1683 	 */
1684 	unsigned long hbinterval;
1685 
1686 	/* This is the max_retrans value for new transports in the
1687 	 * association.
1688 	 */
1689 	__u16 pathmaxrxt;
1690 
1691 	/* Flag that path mtu update is pending */
1692 	__u8   pmtu_pending;
1693 
1694 	/* Association : The smallest PMTU discovered for all of the
1695 	 * PMTU	       : peer's transport addresses.
1696 	 */
1697 	__u32 pathmtu;
1698 
1699 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1700 	__u32 param_flags;
1701 
1702 	__u32 sackfreq;
1703 	/* SACK delay timeout */
1704 	unsigned long sackdelay;
1705 
1706 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1707 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1708 
1709 	/* Transport to which SHUTDOWN chunk was last sent.  */
1710 	struct sctp_transport *shutdown_last_sent_to;
1711 
1712 	/* Transport to which INIT chunk was last sent.  */
1713 	struct sctp_transport *init_last_sent_to;
1714 
1715 	/* How many times have we resent a SHUTDOWN */
1716 	int shutdown_retries;
1717 
1718 	/* Next TSN    : The next TSN number to be assigned to a new
1719 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1720 	 *	       : ACK chunk to the peer and incremented each
1721 	 *	       : time a DATA chunk is assigned a TSN
1722 	 *	       : (normally just prior to transmit or during
1723 	 *	       : fragmentation).
1724 	 */
1725 	__u32 next_tsn;
1726 
1727 	/*
1728 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1729 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1730 	 *	       : received in the INIT or INIT ACK chunk, and
1731 	 *	       : subtracting one from it.
1732 	 *
1733 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1734 	 */
1735 
1736 	__u32 ctsn_ack_point;
1737 
1738 	/* PR-SCTP Advanced.Peer.Ack.Point */
1739 	__u32 adv_peer_ack_point;
1740 
1741 	/* Highest TSN that is acknowledged by incoming SACKs. */
1742 	__u32 highest_sacked;
1743 
1744 	/* TSN marking the fast recovery exit point */
1745 	__u32 fast_recovery_exit;
1746 
1747 	/* Flag to track the current fast recovery state */
1748 	__u8 fast_recovery;
1749 
1750 	/* The number of unacknowledged data chunks.  Reported through
1751 	 * the SCTP_STATUS sockopt.
1752 	 */
1753 	__u16 unack_data;
1754 
1755 	/* The total number of data chunks that we've had to retransmit
1756 	 * as the result of a T3 timer expiration
1757 	 */
1758 	__u32 rtx_data_chunks;
1759 
1760 	/* This is the association's receive buffer space.  This value is used
1761 	 * to set a_rwnd field in an INIT or a SACK chunk.
1762 	 */
1763 	__u32 rwnd;
1764 
1765 	/* This is the last advertised value of rwnd over a SACK chunk. */
1766 	__u32 a_rwnd;
1767 
1768 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1769 	 * to slop over a maximum of the association's frag_point.
1770 	 */
1771 	__u32 rwnd_over;
1772 
1773 	/* Keeps treack of rwnd pressure.  This happens when we have
1774 	 * a window, but not recevie buffer (i.e small packets).  This one
1775 	 * is releases slowly (1 PMTU at a time ).
1776 	 */
1777 	__u32 rwnd_press;
1778 
1779 	/* This is the sndbuf size in use for the association.
1780 	 * This corresponds to the sndbuf size for the association,
1781 	 * as specified in the sk->sndbuf.
1782 	 */
1783 	int sndbuf_used;
1784 
1785 	/* This is the amount of memory that this association has allocated
1786 	 * in the receive path at any given time.
1787 	 */
1788 	atomic_t rmem_alloc;
1789 
1790 	/* This is the wait queue head for send requests waiting on
1791 	 * the association sndbuf space.
1792 	 */
1793 	wait_queue_head_t	wait;
1794 
1795 	/* The message size at which SCTP fragmentation will occur. */
1796 	__u32 frag_point;
1797 	__u32 user_frag;
1798 
1799 	/* Counter used to count INIT errors. */
1800 	int init_err_counter;
1801 
1802 	/* Count the number of INIT cycles (for doubling timeout). */
1803 	int init_cycle;
1804 
1805 	/* Default send parameters. */
1806 	__u16 default_stream;
1807 	__u16 default_flags;
1808 	__u32 default_ppid;
1809 	__u32 default_context;
1810 	__u32 default_timetolive;
1811 
1812 	/* Default receive parameters */
1813 	__u32 default_rcv_context;
1814 
1815 	/* Stream arrays */
1816 	struct sctp_stream stream;
1817 
1818 	/* All outbound chunks go through this structure.  */
1819 	struct sctp_outq outqueue;
1820 
1821 	/* A smart pipe that will handle reordering and fragmentation,
1822 	 * as well as handle passing events up to the ULP.
1823 	 */
1824 	struct sctp_ulpq ulpq;
1825 
1826 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1827 	__u32 last_ecne_tsn;
1828 
1829 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1830 	__u32 last_cwr_tsn;
1831 
1832 	/* How many duplicated TSNs have we seen?  */
1833 	int numduptsns;
1834 
1835 	/* These are to support
1836 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1837 	 *  and Enforcement of Flow and Message Limits"
1838 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1839 	 * or "ADDIP" for short.
1840 	 */
1841 
1842 
1843 
1844 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1845 	 *
1846 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1847 	 * unacknowledged at any one time.  If a sender, after sending
1848 	 * an ASCONF chunk, decides it needs to transfer another
1849 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1850 	 * returns from the previous ASCONF Chunk before sending a
1851 	 * subsequent ASCONF. Note this restriction binds each side,
1852 	 * so at any time two ASCONF may be in-transit on any given
1853 	 * association (one sent from each endpoint).
1854 	 *
1855 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1856 	 * not have an ASCONF in flight, this is NULL.]
1857 	 */
1858 	struct sctp_chunk *addip_last_asconf;
1859 
1860 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1861 	 *
1862 	 * This is needed to implement itmes E1 - E4 of the updated
1863 	 * spec.  Here is the justification:
1864 	 *
1865 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1866 	 * we now need the ability to cache multiple ACKs.  The section
1867 	 * describes in detail how they are cached and cleaned up.
1868 	 */
1869 	struct list_head asconf_ack_list;
1870 
1871 	/* These ASCONF chunks are waiting to be sent.
1872 	 *
1873 	 * These chunaks can't be pushed to outqueue until receiving
1874 	 * ASCONF_ACK for the previous ASCONF indicated by
1875 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1876 	 * is in flight at any time.
1877 	 *
1878 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1879 	 *
1880 	 * In defining the ASCONF Chunk transfer procedures, it is
1881 	 * essential that these transfers MUST NOT cause congestion
1882 	 * within the network.	To achieve this, we place these
1883 	 * restrictions on the transfer of ASCONF Chunks:
1884 	 *
1885 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1886 	 * unacknowledged at any one time.  If a sender, after sending
1887 	 * an ASCONF chunk, decides it needs to transfer another
1888 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1889 	 * returns from the previous ASCONF Chunk before sending a
1890 	 * subsequent ASCONF. Note this restriction binds each side,
1891 	 * so at any time two ASCONF may be in-transit on any given
1892 	 * association (one sent from each endpoint).
1893 	 *
1894 	 *
1895 	 * [I really think this is EXACTLY the sort of intelligence
1896 	 *  which already resides in sctp_outq.	 Please move this
1897 	 *  queue and its supporting logic down there.	--piggy]
1898 	 */
1899 	struct list_head addip_chunk_list;
1900 
1901 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1902 	 *
1903 	 * A2) A serial number should be assigned to the Chunk. The
1904 	 * serial number SHOULD be a monotonically increasing
1905 	 * number. The serial number SHOULD be initialized at
1906 	 * the start of the association to the same value as the
1907 	 * Initial TSN and every time a new ASCONF chunk is created
1908 	 * it is incremented by one after assigning the serial number
1909 	 * to the newly created chunk.
1910 	 *
1911 	 * ADDIP
1912 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1913 	 *
1914 	 * Serial Number : 32 bits (unsigned integer)
1915 	 *
1916 	 * This value represents a Serial Number for the ASCONF
1917 	 * Chunk. The valid range of Serial Number is from 0 to
1918 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1919 	 * after reaching 4294967295.
1920 	 */
1921 	__u32 addip_serial;
1922 	int src_out_of_asoc_ok;
1923 	union sctp_addr *asconf_addr_del_pending;
1924 	struct sctp_transport *new_transport;
1925 
1926 	/* SCTP AUTH: list of the endpoint shared keys.  These
1927 	 * keys are provided out of band by the user applicaton
1928 	 * and can't change during the lifetime of the association
1929 	 */
1930 	struct list_head endpoint_shared_keys;
1931 
1932 	/* SCTP AUTH:
1933 	 * The current generated assocaition shared key (secret)
1934 	 */
1935 	struct sctp_auth_bytes *asoc_shared_key;
1936 
1937 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1938 	 * that we support.
1939 	 */
1940 	__u16 default_hmac_id;
1941 
1942 	__u16 active_key_id;
1943 
1944 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
1945 	     temp:1,		/* Is it a temporary association? */
1946 	     force_delay:1,
1947 	     prsctp_enable:1,
1948 	     reconf_enable:1;
1949 
1950 	__u8 strreset_enable;
1951 	__u8 strreset_outstanding; /* request param count on the fly */
1952 
1953 	__u32 strreset_outseq; /* Update after receiving response */
1954 	__u32 strreset_inseq; /* Update after receiving request */
1955 	__u32 strreset_result[2]; /* save the results of last 2 responses */
1956 
1957 	struct sctp_chunk *strreset_chunk; /* save request chunk */
1958 
1959 	struct sctp_priv_assoc_stats stats;
1960 
1961 	int sent_cnt_removable;
1962 
1963 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1964 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1965 };
1966 
1967 
1968 /* An eyecatcher for determining if we are really looking at an
1969  * association data structure.
1970  */
1971 enum {
1972 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1973 };
1974 
1975 /* Recover the outter association structure. */
1976 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1977 {
1978 	struct sctp_association *asoc;
1979 
1980 	asoc = container_of(base, struct sctp_association, base);
1981 	return asoc;
1982 }
1983 
1984 /* These are function signatures for manipulating associations.	 */
1985 
1986 
1987 struct sctp_association *
1988 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
1989 		     enum sctp_scope scope, gfp_t gfp);
1990 void sctp_association_free(struct sctp_association *);
1991 void sctp_association_put(struct sctp_association *);
1992 void sctp_association_hold(struct sctp_association *);
1993 
1994 struct sctp_transport *sctp_assoc_choose_alter_transport(
1995 	struct sctp_association *, struct sctp_transport *);
1996 void sctp_assoc_update_retran_path(struct sctp_association *);
1997 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1998 					  const union sctp_addr *);
1999 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2000 			    const union sctp_addr *laddr);
2001 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2002 				     const union sctp_addr *address,
2003 				     const gfp_t gfp,
2004 				     const int peer_state);
2005 void sctp_assoc_del_peer(struct sctp_association *asoc,
2006 			 const union sctp_addr *addr);
2007 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2008 			 struct sctp_transport *peer);
2009 void sctp_assoc_control_transport(struct sctp_association *asoc,
2010 				  struct sctp_transport *transport,
2011 				  enum sctp_transport_cmd command,
2012 				  sctp_sn_error_t error);
2013 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2014 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
2015 					   struct net *,
2016 					   const union sctp_addr *,
2017 					   const union sctp_addr *);
2018 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2019 int sctp_assoc_update(struct sctp_association *old,
2020 		      struct sctp_association *new);
2021 
2022 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2023 
2024 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2025 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2026 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2027 void sctp_assoc_set_primary(struct sctp_association *,
2028 			    struct sctp_transport *);
2029 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2030 				    struct sctp_transport *);
2031 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2032 				     enum sctp_scope scope, gfp_t gfp);
2033 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2034 					 struct sctp_cookie*,
2035 					 gfp_t gfp);
2036 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2037 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2038 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2039 					const struct sctp_association *asoc,
2040 					__be32 serial);
2041 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2042 
2043 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2044 			const union sctp_addr *ss2);
2045 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2046 
2047 /* A convenience structure to parse out SCTP specific CMSGs. */
2048 struct sctp_cmsgs {
2049 	struct sctp_initmsg *init;
2050 	struct sctp_sndrcvinfo *srinfo;
2051 	struct sctp_sndinfo *sinfo;
2052 };
2053 
2054 /* Structure for tracking memory objects */
2055 struct sctp_dbg_objcnt_entry {
2056 	char *label;
2057 	atomic_t *counter;
2058 };
2059 
2060 #endif /* __sctp_structs_h__ */
2061