xref: /openbmc/linux/include/net/sctp/structs.h (revision feac8c8b)
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 #include <net/sctp/stream_interleave.h>
93 
94 /* Structures useful for managing bind/connect. */
95 
96 struct sctp_bind_bucket {
97 	unsigned short	port;
98 	unsigned short	fastreuse;
99 	struct hlist_node	node;
100 	struct hlist_head	owner;
101 	struct net	*net;
102 };
103 
104 struct sctp_bind_hashbucket {
105 	spinlock_t	lock;
106 	struct hlist_head	chain;
107 };
108 
109 /* Used for hashing all associations.  */
110 struct sctp_hashbucket {
111 	rwlock_t	lock;
112 	struct hlist_head	chain;
113 } __attribute__((__aligned__(8)));
114 
115 
116 /* The SCTP globals structure. */
117 extern struct sctp_globals {
118 	/* This is a list of groups of functions for each address
119 	 * family that we support.
120 	 */
121 	struct list_head address_families;
122 
123 	/* This is the hash of all endpoints. */
124 	struct sctp_hashbucket *ep_hashtable;
125 	/* This is the sctp port control hash.	*/
126 	struct sctp_bind_hashbucket *port_hashtable;
127 	/* This is the hash of all transports. */
128 	struct rhltable transport_hashtable;
129 
130 	/* Sizes of above hashtables. */
131 	int ep_hashsize;
132 	int port_hashsize;
133 
134 	/* Default initialization values to be applied to new associations. */
135 	__u16 max_instreams;
136 	__u16 max_outstreams;
137 
138 	/* Flag to indicate whether computing and verifying checksum
139 	 * is disabled. */
140         bool checksum_disable;
141 } sctp_globals;
142 
143 #define sctp_max_instreams		(sctp_globals.max_instreams)
144 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
145 #define sctp_address_families		(sctp_globals.address_families)
146 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
147 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
148 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
149 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
150 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
151 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
152 
153 /* SCTP Socket type: UDP or TCP style. */
154 enum sctp_socket_type {
155 	SCTP_SOCKET_UDP = 0,
156 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
157 	SCTP_SOCKET_TCP
158 };
159 
160 /* Per socket SCTP information. */
161 struct sctp_sock {
162 	/* inet_sock has to be the first member of sctp_sock */
163 	struct inet_sock inet;
164 	/* What kind of a socket is this? */
165 	enum sctp_socket_type type;
166 
167 	/* PF_ family specific functions.  */
168 	struct sctp_pf *pf;
169 
170 	/* Access to HMAC transform. */
171 	struct crypto_shash *hmac;
172 	char *sctp_hmac_alg;
173 
174 	/* What is our base endpointer? */
175 	struct sctp_endpoint *ep;
176 
177 	struct sctp_bind_bucket *bind_hash;
178 	/* Various Socket Options.  */
179 	__u16 default_stream;
180 	__u32 default_ppid;
181 	__u16 default_flags;
182 	__u32 default_context;
183 	__u32 default_timetolive;
184 	__u32 default_rcv_context;
185 	int max_burst;
186 
187 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
188 	 * the destination address every heartbeat interval. This value
189 	 * will be inherited by all new associations.
190 	 */
191 	__u32 hbinterval;
192 
193 	/* This is the max_retrans value for new associations. */
194 	__u16 pathmaxrxt;
195 
196 	/* The initial Path MTU to use for new associations. */
197 	__u32 pathmtu;
198 
199 	/* The default SACK delay timeout for new associations. */
200 	__u32 sackdelay;
201 	__u32 sackfreq;
202 
203 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
204 	__u32 param_flags;
205 
206 	struct sctp_rtoinfo rtoinfo;
207 	struct sctp_paddrparams paddrparam;
208 	struct sctp_assocparams assocparams;
209 
210 	/*
211 	 * These two structures must be grouped together for the usercopy
212 	 * whitelist region.
213 	 */
214 	struct sctp_event_subscribe subscribe;
215 	struct sctp_initmsg initmsg;
216 
217 	int user_frag;
218 
219 	__u32 autoclose;
220 	__u32 adaptation_ind;
221 	__u32 pd_point;
222 	__u16	nodelay:1,
223 		disable_fragments:1,
224 		v4mapped:1,
225 		frag_interleave:1,
226 		strm_interleave:1,
227 		recvrcvinfo:1,
228 		recvnxtinfo:1,
229 		data_ready_signalled:1;
230 
231 	atomic_t pd_mode;
232 	/* Receive to here while partial delivery is in effect. */
233 	struct sk_buff_head pd_lobby;
234 
235 	/* These must be the last fields, as they will skipped on copies,
236 	 * like on accept and peeloff operations
237 	 */
238 	struct list_head auto_asconf_list;
239 	int do_auto_asconf;
240 };
241 
242 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
243 {
244        return (struct sctp_sock *)sk;
245 }
246 
247 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
248 {
249        return (struct sock *)sp;
250 }
251 
252 #if IS_ENABLED(CONFIG_IPV6)
253 struct sctp6_sock {
254        struct sctp_sock  sctp;
255        struct ipv6_pinfo inet6;
256 };
257 #endif /* CONFIG_IPV6 */
258 
259 
260 /* This is our APPLICATION-SPECIFIC state cookie.
261  * THIS IS NOT DICTATED BY THE SPECIFICATION.
262  */
263 /* These are the parts of an association which we send in the cookie.
264  * Most of these are straight out of:
265  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
266  *
267  */
268 
269 struct sctp_cookie {
270 
271 	/* My	       : Tag expected in every inbound packet and sent
272 	 * Verification: in the INIT or INIT ACK chunk.
273 	 * Tag	       :
274 	 */
275 	__u32 my_vtag;
276 
277 	/* Peer's      : Tag expected in every outbound packet except
278 	 * Verification: in the INIT chunk.
279 	 * Tag	       :
280 	 */
281 	__u32 peer_vtag;
282 
283 	/* The rest of these are not from the spec, but really need to
284 	 * be in the cookie.
285 	 */
286 
287 	/* My Tie Tag  : Assist in discovering a restarting association. */
288 	__u32 my_ttag;
289 
290 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
291 	__u32 peer_ttag;
292 
293 	/* When does this cookie expire? */
294 	ktime_t expiration;
295 
296 	/* Number of inbound/outbound streams which are set
297 	 * and negotiated during the INIT process.
298 	 */
299 	__u16 sinit_num_ostreams;
300 	__u16 sinit_max_instreams;
301 
302 	/* This is the first sequence number I used.  */
303 	__u32 initial_tsn;
304 
305 	/* This holds the originating address of the INIT packet.  */
306 	union sctp_addr peer_addr;
307 
308 	/* IG Section 2.35.3
309 	 * Include the source port of the INIT-ACK
310 	 */
311 	__u16		my_port;
312 
313 	__u8 prsctp_capable;
314 
315 	/* Padding for future use */
316 	__u8 padding;
317 
318 	__u32 adaptation_ind;
319 
320 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
321 			 SCTP_AUTH_RANDOM_LENGTH];
322 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
323 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
324 
325 	/* This is a shim for my peer's INIT packet, followed by
326 	 * a copy of the raw address list of the association.
327 	 * The length of the raw address list is saved in the
328 	 * raw_addr_list_len field, which will be used at the time when
329 	 * the association TCB is re-constructed from the cookie.
330 	 */
331 	__u32 raw_addr_list_len;
332 	struct sctp_init_chunk peer_init[0];
333 };
334 
335 
336 /* The format of our cookie that we send to our peer. */
337 struct sctp_signed_cookie {
338 	__u8 signature[SCTP_SECRET_SIZE];
339 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
340 	struct sctp_cookie c;
341 } __packed;
342 
343 /* This is another convenience type to allocate memory for address
344  * params for the maximum size and pass such structures around
345  * internally.
346  */
347 union sctp_addr_param {
348 	struct sctp_paramhdr p;
349 	struct sctp_ipv4addr_param v4;
350 	struct sctp_ipv6addr_param v6;
351 };
352 
353 /* A convenience type to allow walking through the various
354  * parameters and avoid casting all over the place.
355  */
356 union sctp_params {
357 	void *v;
358 	struct sctp_paramhdr *p;
359 	struct sctp_cookie_preserve_param *life;
360 	struct sctp_hostname_param *dns;
361 	struct sctp_cookie_param *cookie;
362 	struct sctp_supported_addrs_param *sat;
363 	struct sctp_ipv4addr_param *v4;
364 	struct sctp_ipv6addr_param *v6;
365 	union sctp_addr_param *addr;
366 	struct sctp_adaptation_ind_param *aind;
367 	struct sctp_supported_ext_param *ext;
368 	struct sctp_random_param *random;
369 	struct sctp_chunks_param *chunks;
370 	struct sctp_hmac_algo_param *hmac_algo;
371 	struct sctp_addip_param *addip;
372 };
373 
374 /* RFC 2960.  Section 3.3.5 Heartbeat.
375  *    Heartbeat Information: variable length
376  *    The Sender-specific Heartbeat Info field should normally include
377  *    information about the sender's current time when this HEARTBEAT
378  *    chunk is sent and the destination transport address to which this
379  *    HEARTBEAT is sent (see Section 8.3).
380  */
381 struct sctp_sender_hb_info {
382 	struct sctp_paramhdr param_hdr;
383 	union sctp_addr daddr;
384 	unsigned long sent_at;
385 	__u64 hb_nonce;
386 };
387 
388 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
389 		     gfp_t gfp);
390 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
391 void sctp_stream_free(struct sctp_stream *stream);
392 void sctp_stream_clear(struct sctp_stream *stream);
393 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
394 
395 /* What is the current SSN number for this stream? */
396 #define sctp_ssn_peek(stream, type, sid) \
397 	((stream)->type[sid].ssn)
398 
399 /* Return the next SSN number for this stream.	*/
400 #define sctp_ssn_next(stream, type, sid) \
401 	((stream)->type[sid].ssn++)
402 
403 /* Skip over this ssn and all below. */
404 #define sctp_ssn_skip(stream, type, sid, ssn) \
405 	((stream)->type[sid].ssn = ssn + 1)
406 
407 /* What is the current MID number for this stream? */
408 #define sctp_mid_peek(stream, type, sid) \
409 	((stream)->type[sid].mid)
410 
411 /* Return the next MID number for this stream.  */
412 #define sctp_mid_next(stream, type, sid) \
413 	((stream)->type[sid].mid++)
414 
415 /* Skip over this mid and all below. */
416 #define sctp_mid_skip(stream, type, sid, mid) \
417 	((stream)->type[sid].mid = mid + 1)
418 
419 #define sctp_stream_in(asoc, sid) (&(asoc)->stream.in[sid])
420 
421 /* What is the current MID_uo number for this stream? */
422 #define sctp_mid_uo_peek(stream, type, sid) \
423 	((stream)->type[sid].mid_uo)
424 
425 /* Return the next MID_uo number for this stream.  */
426 #define sctp_mid_uo_next(stream, type, sid) \
427 	((stream)->type[sid].mid_uo++)
428 
429 /*
430  * Pointers to address related SCTP functions.
431  * (i.e. things that depend on the address family.)
432  */
433 struct sctp_af {
434 	int		(*sctp_xmit)	(struct sk_buff *skb,
435 					 struct sctp_transport *);
436 	int		(*setsockopt)	(struct sock *sk,
437 					 int level,
438 					 int optname,
439 					 char __user *optval,
440 					 unsigned int optlen);
441 	int		(*getsockopt)	(struct sock *sk,
442 					 int level,
443 					 int optname,
444 					 char __user *optval,
445 					 int __user *optlen);
446 	int		(*compat_setsockopt)	(struct sock *sk,
447 					 int level,
448 					 int optname,
449 					 char __user *optval,
450 					 unsigned int optlen);
451 	int		(*compat_getsockopt)	(struct sock *sk,
452 					 int level,
453 					 int optname,
454 					 char __user *optval,
455 					 int __user *optlen);
456 	void		(*get_dst)	(struct sctp_transport *t,
457 					 union sctp_addr *saddr,
458 					 struct flowi *fl,
459 					 struct sock *sk);
460 	void		(*get_saddr)	(struct sctp_sock *sk,
461 					 struct sctp_transport *t,
462 					 struct flowi *fl);
463 	void		(*copy_addrlist) (struct list_head *,
464 					  struct net_device *);
465 	int		(*cmp_addr)	(const union sctp_addr *addr1,
466 					 const union sctp_addr *addr2);
467 	void		(*addr_copy)	(union sctp_addr *dst,
468 					 union sctp_addr *src);
469 	void		(*from_skb)	(union sctp_addr *,
470 					 struct sk_buff *skb,
471 					 int saddr);
472 	void		(*from_sk)	(union sctp_addr *,
473 					 struct sock *sk);
474 	void		(*from_addr_param) (union sctp_addr *,
475 					    union sctp_addr_param *,
476 					    __be16 port, int iif);
477 	int		(*to_addr_param) (const union sctp_addr *,
478 					  union sctp_addr_param *);
479 	int		(*addr_valid)	(union sctp_addr *,
480 					 struct sctp_sock *,
481 					 const struct sk_buff *);
482 	enum sctp_scope	(*scope)(union sctp_addr *);
483 	void		(*inaddr_any)	(union sctp_addr *, __be16);
484 	int		(*is_any)	(const union sctp_addr *);
485 	int		(*available)	(union sctp_addr *,
486 					 struct sctp_sock *);
487 	int		(*skb_iif)	(const struct sk_buff *sk);
488 	int		(*is_ce)	(const struct sk_buff *sk);
489 	void		(*seq_dump_addr)(struct seq_file *seq,
490 					 union sctp_addr *addr);
491 	void		(*ecn_capable)(struct sock *sk);
492 	__u16		net_header_len;
493 	int		sockaddr_len;
494 	sa_family_t	sa_family;
495 	struct list_head list;
496 };
497 
498 struct sctp_af *sctp_get_af_specific(sa_family_t);
499 int sctp_register_af(struct sctp_af *);
500 
501 /* Protocol family functions. */
502 struct sctp_pf {
503 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
504 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
505 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
506 	int  (*cmp_addr) (const union sctp_addr *,
507 			  const union sctp_addr *,
508 			  struct sctp_sock *);
509 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
510 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
511 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
512 	struct sock *(*create_accept_sk) (struct sock *sk,
513 					  struct sctp_association *asoc,
514 					  bool kern);
515 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
516 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
517 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
518 	struct sctp_af *af;
519 };
520 
521 
522 /* Structure to track chunk fragments that have been acked, but peer
523  * fragments of the same message have not.
524  */
525 struct sctp_datamsg {
526 	/* Chunks waiting to be submitted to lower layer. */
527 	struct list_head chunks;
528 	/* Reference counting. */
529 	refcount_t refcnt;
530 	/* When is this message no longer interesting to the peer? */
531 	unsigned long expires_at;
532 	/* Did the messenge fail to send? */
533 	int send_error;
534 	u8 send_failed:1,
535 	   can_delay:1,	/* should this message be Nagle delayed */
536 	   abandoned:1;	/* should this message be abandoned */
537 };
538 
539 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
540 					    struct sctp_sndrcvinfo *,
541 					    struct iov_iter *);
542 void sctp_datamsg_free(struct sctp_datamsg *);
543 void sctp_datamsg_put(struct sctp_datamsg *);
544 void sctp_chunk_fail(struct sctp_chunk *, int error);
545 int sctp_chunk_abandoned(struct sctp_chunk *);
546 
547 /* RFC2960 1.4 Key Terms
548  *
549  * o Chunk: A unit of information within an SCTP packet, consisting of
550  * a chunk header and chunk-specific content.
551  *
552  * As a matter of convenience, we remember the SCTP common header for
553  * each chunk as well as a few other header pointers...
554  */
555 struct sctp_chunk {
556 	struct list_head list;
557 
558 	refcount_t refcnt;
559 
560 	/* How many times this chunk have been sent, for prsctp RTX policy */
561 	int sent_count;
562 
563 	union {
564 		/* This is our link to the per-transport transmitted list.  */
565 		struct list_head transmitted_list;
566 		/* List in specific stream outq */
567 		struct list_head stream_list;
568 	};
569 
570 	/* This field is used by chunks that hold fragmented data.
571 	 * For the first fragment this is the list that holds the rest of
572 	 * fragments. For the remaining fragments, this is the link to the
573 	 * frag_list maintained in the first fragment.
574 	 */
575 	struct list_head frag_list;
576 
577 	/* This points to the sk_buff containing the actual data.  */
578 	struct sk_buff *skb;
579 
580 	/* In case of GSO packets, this will store the head one */
581 	struct sk_buff *head_skb;
582 
583 	/* These are the SCTP headers by reverse order in a packet.
584 	 * Note that some of these may happen more than once.  In that
585 	 * case, we point at the "current" one, whatever that means
586 	 * for that level of header.
587 	 */
588 
589 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
590 	union sctp_params param_hdr;
591 	union {
592 		__u8 *v;
593 		struct sctp_datahdr *data_hdr;
594 		struct sctp_inithdr *init_hdr;
595 		struct sctp_sackhdr *sack_hdr;
596 		struct sctp_heartbeathdr *hb_hdr;
597 		struct sctp_sender_hb_info *hbs_hdr;
598 		struct sctp_shutdownhdr *shutdown_hdr;
599 		struct sctp_signed_cookie *cookie_hdr;
600 		struct sctp_ecnehdr *ecne_hdr;
601 		struct sctp_cwrhdr *ecn_cwr_hdr;
602 		struct sctp_errhdr *err_hdr;
603 		struct sctp_addiphdr *addip_hdr;
604 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
605 		struct sctp_authhdr *auth_hdr;
606 		struct sctp_idatahdr *idata_hdr;
607 		struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
608 	} subh;
609 
610 	__u8 *chunk_end;
611 
612 	struct sctp_chunkhdr *chunk_hdr;
613 	struct sctphdr *sctp_hdr;
614 
615 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
616 	struct sctp_sndrcvinfo sinfo;
617 
618 	/* Which association does this belong to?  */
619 	struct sctp_association *asoc;
620 
621 	/* What endpoint received this chunk? */
622 	struct sctp_ep_common *rcvr;
623 
624 	/* We fill this in if we are calculating RTT. */
625 	unsigned long sent_at;
626 
627 	/* What is the origin IP address for this chunk?  */
628 	union sctp_addr source;
629 	/* Destination address for this chunk. */
630 	union sctp_addr dest;
631 
632 	/* For outbound message, track all fragments for SEND_FAILED. */
633 	struct sctp_datamsg *msg;
634 
635 	/* For an inbound chunk, this tells us where it came from.
636 	 * For an outbound chunk, it tells us where we'd like it to
637 	 * go.	It is NULL if we have no preference.
638 	 */
639 	struct sctp_transport *transport;
640 
641 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
642 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
643 	 * spec violates the principle premis that all chunks are processed
644 	 * in order.
645 	 */
646 	struct sk_buff *auth_chunk;
647 
648 #define SCTP_CAN_FRTX 0x0
649 #define SCTP_NEED_FRTX 0x1
650 #define SCTP_DONT_FRTX 0x2
651 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
652 		has_tsn:1,		/* Does this chunk have a TSN yet? */
653 		has_ssn:1,		/* Does this chunk have a SSN yet? */
654 #define has_mid has_ssn
655 		singleton:1,		/* Only chunk in the packet? */
656 		end_of_packet:1,	/* Last chunk in the packet? */
657 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
658 		pdiscard:1,		/* Discard the whole packet now? */
659 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
660 		data_accepted:1,	/* At least 1 chunk accepted */
661 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
662 		has_asconf:1,		/* IN: have seen an asconf before */
663 		tsn_missing_report:2,	/* Data chunk missing counter. */
664 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
665 };
666 
667 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
668 void sctp_chunk_hold(struct sctp_chunk *);
669 void sctp_chunk_put(struct sctp_chunk *);
670 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
671 			  struct iov_iter *from);
672 void sctp_chunk_free(struct sctp_chunk *);
673 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
674 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
675 				 const struct sctp_association *,
676 				 struct sock *, gfp_t gfp);
677 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
678 		     union sctp_addr *);
679 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
680 
681 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
682 {
683 	return ntohs(ch->subh.data_hdr->stream);
684 }
685 
686 enum {
687 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
688 	SCTP_ADDR_SRC,		/* address can be used as source */
689 	SCTP_ADDR_DEL,		/* address about to be deleted */
690 };
691 
692 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
693 struct sctp_sockaddr_entry {
694 	struct list_head list;
695 	struct rcu_head	rcu;
696 	union sctp_addr a;
697 	__u8 state;
698 	__u8 valid;
699 };
700 
701 #define SCTP_ADDRESS_TICK_DELAY	500
702 
703 /* This structure holds lists of chunks as we are assembling for
704  * transmission.
705  */
706 struct sctp_packet {
707 	/* These are the SCTP header values (host order) for the packet. */
708 	__u16 source_port;
709 	__u16 destination_port;
710 	__u32 vtag;
711 
712 	/* This contains the payload chunks.  */
713 	struct list_head chunk_list;
714 
715 	/* This is the overhead of the sctp and ip headers. */
716 	size_t overhead;
717 	/* This is the total size of all chunks INCLUDING padding.  */
718 	size_t size;
719 	/* This is the maximum size this packet may have */
720 	size_t max_size;
721 
722 	/* The packet is destined for this transport address.
723 	 * The function we finally use to pass down to the next lower
724 	 * layer lives in the transport structure.
725 	 */
726 	struct sctp_transport *transport;
727 
728 	/* pointer to the auth chunk for this packet */
729 	struct sctp_chunk *auth;
730 
731 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
732 	    has_sack:1,		/* This packet contains a SACK chunk. */
733 	    has_auth:1,		/* This packet contains an AUTH chunk */
734 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
735 	    ipfragok:1;		/* So let ip fragment this packet */
736 };
737 
738 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
739 		      __u16 sport, __u16 dport);
740 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
741 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
742 					  struct sctp_chunk *chunk,
743 					  int one_packet, gfp_t gfp);
744 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
745 					struct sctp_chunk *chunk);
746 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
747 void sctp_packet_free(struct sctp_packet *);
748 
749 static inline int sctp_packet_empty(struct sctp_packet *packet)
750 {
751 	return packet->size == packet->overhead;
752 }
753 
754 /* This represents a remote transport address.
755  * For local transport addresses, we just use union sctp_addr.
756  *
757  * RFC2960 Section 1.4 Key Terms
758  *
759  *   o	Transport address:  A Transport Address is traditionally defined
760  *	by Network Layer address, Transport Layer protocol and Transport
761  *	Layer port number.  In the case of SCTP running over IP, a
762  *	transport address is defined by the combination of an IP address
763  *	and an SCTP port number (where SCTP is the Transport protocol).
764  *
765  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
766  *
767  *   o	The sender keeps a separate congestion control parameter set for
768  *	each of the destination addresses it can send to (not each
769  *	source-destination pair but for each destination).  The parameters
770  *	should decay if the address is not used for a long enough time
771  *	period.
772  *
773  */
774 struct sctp_transport {
775 	/* A list of transports. */
776 	struct list_head transports;
777 	struct rhlist_head node;
778 
779 	/* Reference counting. */
780 	refcount_t refcnt;
781 		/* RTO-Pending : A flag used to track if one of the DATA
782 		 *		chunks sent to this address is currently being
783 		 *		used to compute a RTT. If this flag is 0,
784 		 *		the next DATA chunk sent to this destination
785 		 *		should be used to compute a RTT and this flag
786 		 *		should be set. Every time the RTT
787 		 *		calculation completes (i.e. the DATA chunk
788 		 *		is SACK'd) clear this flag.
789 		 */
790 	__u32	rto_pending:1,
791 
792 		/*
793 		 * hb_sent : a flag that signals that we have a pending
794 		 * heartbeat.
795 		 */
796 		hb_sent:1,
797 
798 		/* Is the Path MTU update pending on this tranport */
799 		pmtu_pending:1,
800 
801 		dst_pending_confirm:1,	/* need to confirm neighbour */
802 
803 		/* Has this transport moved the ctsn since we last sacked */
804 		sack_generation:1;
805 	u32 dst_cookie;
806 
807 	struct flowi fl;
808 
809 	/* This is the peer's IP address and port. */
810 	union sctp_addr ipaddr;
811 
812 	/* These are the functions we call to handle LLP stuff.	 */
813 	struct sctp_af *af_specific;
814 
815 	/* Which association do we belong to?  */
816 	struct sctp_association *asoc;
817 
818 	/* RFC2960
819 	 *
820 	 * 12.3 Per Transport Address Data
821 	 *
822 	 * For each destination transport address in the peer's
823 	 * address list derived from the INIT or INIT ACK chunk, a
824 	 * number of data elements needs to be maintained including:
825 	 */
826 	/* RTO	       : The current retransmission timeout value.  */
827 	unsigned long rto;
828 
829 	__u32 rtt;		/* This is the most recent RTT.	 */
830 
831 	/* RTTVAR      : The current RTT variation.  */
832 	__u32 rttvar;
833 
834 	/* SRTT	       : The current smoothed round trip time.	*/
835 	__u32 srtt;
836 
837 	/*
838 	 * These are the congestion stats.
839 	 */
840 	/* cwnd	       : The current congestion window.	 */
841 	__u32 cwnd;		  /* This is the actual cwnd.  */
842 
843 	/* ssthresh    : The current slow start threshold value.  */
844 	__u32 ssthresh;
845 
846 	/* partial     : The tracking method for increase of cwnd when in
847 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
848 	 */
849 	__u32 partial_bytes_acked;
850 
851 	/* Data that has been sent, but not acknowledged. */
852 	__u32 flight_size;
853 
854 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
855 
856 	/* Destination */
857 	struct dst_entry *dst;
858 	/* Source address. */
859 	union sctp_addr saddr;
860 
861 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
862 	 * the destination address every heartbeat interval.
863 	 */
864 	unsigned long hbinterval;
865 
866 	/* SACK delay timeout */
867 	unsigned long sackdelay;
868 	__u32 sackfreq;
869 
870 	/* When was the last time that we heard from this transport? We use
871 	 * this to pick new active and retran paths.
872 	 */
873 	ktime_t last_time_heard;
874 
875 	/* When was the last time that we sent a chunk using this
876 	 * transport? We use this to check for idle transports
877 	 */
878 	unsigned long last_time_sent;
879 
880 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
881 	 * indication based on ECNE chunk.
882 	 */
883 	unsigned long last_time_ecne_reduced;
884 
885 	/* This is the max_retrans value for the transport and will
886 	 * be initialized from the assocs value.  This can be changed
887 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
888 	 */
889 	__u16 pathmaxrxt;
890 
891 	/* This is the partially failed retrans value for the transport
892 	 * and will be initialized from the assocs value.  This can be changed
893 	 * using the SCTP_PEER_ADDR_THLDS socket option
894 	 */
895 	int pf_retrans;
896 	/* PMTU	      : The current known path MTU.  */
897 	__u32 pathmtu;
898 
899 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
900 	__u32 param_flags;
901 
902 	/* The number of times INIT has been sent on this transport. */
903 	int init_sent_count;
904 
905 	/* state       : The current state of this destination,
906 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
907 	 */
908 	int state;
909 
910 	/* These are the error stats for this destination.  */
911 
912 	/* Error count : The current error count for this destination.	*/
913 	unsigned short error_count;
914 
915 	/* Per	       : A timer used by each destination.
916 	 * Destination :
917 	 * Timer       :
918 	 *
919 	 * [Everywhere else in the text this is called T3-rtx. -ed]
920 	 */
921 	struct timer_list T3_rtx_timer;
922 
923 	/* Heartbeat timer is per destination. */
924 	struct timer_list hb_timer;
925 
926 	/* Timer to handle ICMP proto unreachable envets */
927 	struct timer_list proto_unreach_timer;
928 
929 	/* Timer to handler reconf chunk rtx */
930 	struct timer_list reconf_timer;
931 
932 	/* Since we're using per-destination retransmission timers
933 	 * (see above), we're also using per-destination "transmitted"
934 	 * queues.  This probably ought to be a private struct
935 	 * accessible only within the outqueue, but it's not, yet.
936 	 */
937 	struct list_head transmitted;
938 
939 	/* We build bundle-able packets for this transport here.  */
940 	struct sctp_packet packet;
941 
942 	/* This is the list of transports that have chunks to send.  */
943 	struct list_head send_ready;
944 
945 	/* State information saved for SFR_CACC algorithm. The key
946 	 * idea in SFR_CACC is to maintain state at the sender on a
947 	 * per-destination basis when a changeover happens.
948 	 *	char changeover_active;
949 	 *	char cycling_changeover;
950 	 *	__u32 next_tsn_at_change;
951 	 *	char cacc_saw_newack;
952 	 */
953 	struct {
954 		/* An unsigned integer, which stores the next TSN to be
955 		 * used by the sender, at the moment of changeover.
956 		 */
957 		__u32 next_tsn_at_change;
958 
959 		/* A flag which indicates the occurrence of a changeover */
960 		char changeover_active;
961 
962 		/* A flag which indicates whether the change of primary is
963 		 * the first switch to this destination address during an
964 		 * active switch.
965 		 */
966 		char cycling_changeover;
967 
968 		/* A temporary flag, which is used during the processing of
969 		 * a SACK to estimate the causative TSN(s)'s group.
970 		 */
971 		char cacc_saw_newack;
972 	} cacc;
973 
974 	/* 64-bit random number sent with heartbeat. */
975 	__u64 hb_nonce;
976 
977 	struct rcu_head rcu;
978 };
979 
980 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
981 					  gfp_t);
982 void sctp_transport_set_owner(struct sctp_transport *,
983 			      struct sctp_association *);
984 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
985 			  struct sctp_sock *);
986 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
987 void sctp_transport_free(struct sctp_transport *);
988 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
989 void sctp_transport_reset_hb_timer(struct sctp_transport *);
990 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
991 int sctp_transport_hold(struct sctp_transport *);
992 void sctp_transport_put(struct sctp_transport *);
993 void sctp_transport_update_rto(struct sctp_transport *, __u32);
994 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
995 void sctp_transport_lower_cwnd(struct sctp_transport *t,
996 			       enum sctp_lower_cwnd reason);
997 void sctp_transport_burst_limited(struct sctp_transport *);
998 void sctp_transport_burst_reset(struct sctp_transport *);
999 unsigned long sctp_transport_timeout(struct sctp_transport *);
1000 void sctp_transport_reset(struct sctp_transport *t);
1001 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1002 void sctp_transport_immediate_rtx(struct sctp_transport *);
1003 void sctp_transport_dst_release(struct sctp_transport *t);
1004 void sctp_transport_dst_confirm(struct sctp_transport *t);
1005 
1006 
1007 /* This is the structure we use to queue packets as they come into
1008  * SCTP.  We write packets to it and read chunks from it.
1009  */
1010 struct sctp_inq {
1011 	/* This is actually a queue of sctp_chunk each
1012 	 * containing a partially decoded packet.
1013 	 */
1014 	struct list_head in_chunk_list;
1015 	/* This is the packet which is currently off the in queue and is
1016 	 * being worked on through the inbound chunk processing.
1017 	 */
1018 	struct sctp_chunk *in_progress;
1019 
1020 	/* This is the delayed task to finish delivering inbound
1021 	 * messages.
1022 	 */
1023 	struct work_struct immediate;
1024 };
1025 
1026 void sctp_inq_init(struct sctp_inq *);
1027 void sctp_inq_free(struct sctp_inq *);
1028 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1029 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1030 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1031 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1032 
1033 /* This is the structure we use to hold outbound chunks.  You push
1034  * chunks in and they automatically pop out the other end as bundled
1035  * packets (it calls (*output_handler)()).
1036  *
1037  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1038  * and 8.2 of the v13 draft.
1039  *
1040  * It handles retransmissions.	The connection to the timeout portion
1041  * of the state machine is through sctp_..._timeout() and timeout_handler.
1042  *
1043  * If you feed it SACKs, it will eat them.
1044  *
1045  * If you give it big chunks, it will fragment them.
1046  *
1047  * It assigns TSN's to data chunks.  This happens at the last possible
1048  * instant before transmission.
1049  *
1050  * When free()'d, it empties itself out via output_handler().
1051  */
1052 struct sctp_outq {
1053 	struct sctp_association *asoc;
1054 
1055 	/* Data pending that has never been transmitted.  */
1056 	struct list_head out_chunk_list;
1057 
1058 	/* Stream scheduler being used */
1059 	struct sctp_sched_ops *sched;
1060 
1061 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1062 
1063 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1064 	unsigned int error;
1065 
1066 	/* These are control chunks we want to send.  */
1067 	struct list_head control_chunk_list;
1068 
1069 	/* These are chunks that have been sacked but are above the
1070 	 * CTSN, or cumulative tsn ack point.
1071 	 */
1072 	struct list_head sacked;
1073 
1074 	/* Put chunks on this list to schedule them for
1075 	 * retransmission.
1076 	 */
1077 	struct list_head retransmit;
1078 
1079 	/* Put chunks on this list to save them for FWD TSN processing as
1080 	 * they were abandoned.
1081 	 */
1082 	struct list_head abandoned;
1083 
1084 	/* How many unackd bytes do we have in-flight?	*/
1085 	__u32 outstanding_bytes;
1086 
1087 	/* Are we doing fast-rtx on this queue */
1088 	char fast_rtx;
1089 
1090 	/* Corked? */
1091 	char cork;
1092 };
1093 
1094 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1095 void sctp_outq_teardown(struct sctp_outq *);
1096 void sctp_outq_free(struct sctp_outq*);
1097 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1098 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1099 int sctp_outq_is_empty(const struct sctp_outq *);
1100 void sctp_outq_restart(struct sctp_outq *);
1101 
1102 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1103 		     enum sctp_retransmit_reason reason);
1104 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1105 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1106 void sctp_prsctp_prune(struct sctp_association *asoc,
1107 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1108 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1109 /* Uncork and flush an outqueue.  */
1110 static inline void sctp_outq_cork(struct sctp_outq *q)
1111 {
1112 	q->cork = 1;
1113 }
1114 
1115 /* SCTP skb control block.
1116  * sctp_input_cb is currently used on rx and sock rx queue
1117  */
1118 struct sctp_input_cb {
1119 	union {
1120 		struct inet_skb_parm	h4;
1121 #if IS_ENABLED(CONFIG_IPV6)
1122 		struct inet6_skb_parm	h6;
1123 #endif
1124 	} header;
1125 	struct sctp_chunk *chunk;
1126 	struct sctp_af *af;
1127 };
1128 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1129 
1130 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1131 {
1132 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1133 
1134 	return chunk->head_skb ? : skb;
1135 }
1136 
1137 /* These bind address data fields common between endpoints and associations */
1138 struct sctp_bind_addr {
1139 
1140 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1141 	 *
1142 	 * SCTP Port:	The local SCTP port number the endpoint is
1143 	 *		bound to.
1144 	 */
1145 	__u16 port;
1146 
1147 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1148 	 *
1149 	 * Address List: The list of IP addresses that this instance
1150 	 *	has bound.  This information is passed to one's
1151 	 *	peer(s) in INIT and INIT ACK chunks.
1152 	 */
1153 	struct list_head address_list;
1154 };
1155 
1156 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1157 void sctp_bind_addr_free(struct sctp_bind_addr *);
1158 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1159 			const struct sctp_bind_addr *src,
1160 			enum sctp_scope scope, gfp_t gfp,
1161 			int flags);
1162 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1163 			const struct sctp_bind_addr *src,
1164 			gfp_t gfp);
1165 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1166 		       int new_size, __u8 addr_state, gfp_t gfp);
1167 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1168 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1169 			 struct sctp_sock *);
1170 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1171 			 struct sctp_sock *, struct sctp_sock *);
1172 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1173 			 const union sctp_addr *addr);
1174 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1175 					const union sctp_addr	*addrs,
1176 					int			addrcnt,
1177 					struct sctp_sock	*opt);
1178 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1179 					 int *addrs_len,
1180 					 gfp_t gfp);
1181 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1182 			   __u16 port, gfp_t gfp);
1183 
1184 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1185 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1186 		  const enum sctp_scope scope);
1187 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1188 int sctp_is_ep_boundall(struct sock *sk);
1189 
1190 
1191 /* What type of endpoint?  */
1192 enum sctp_endpoint_type {
1193 	SCTP_EP_TYPE_SOCKET,
1194 	SCTP_EP_TYPE_ASSOCIATION,
1195 };
1196 
1197 /*
1198  * A common base class to bridge the implmentation view of a
1199  * socket (usually listening) endpoint versus an association's
1200  * local endpoint.
1201  * This common structure is useful for several purposes:
1202  *   1) Common interface for lookup routines.
1203  *	a) Subfunctions work for either endpoint or association
1204  *	b) Single interface to lookup allows hiding the lookup lock rather
1205  *	   than acquiring it externally.
1206  *   2) Common interface for the inbound chunk handling/state machine.
1207  *   3) Common object handling routines for reference counting, etc.
1208  *   4) Disentangle association lookup from endpoint lookup, where we
1209  *	do not have to find our endpoint to find our association.
1210  *
1211  */
1212 
1213 struct sctp_ep_common {
1214 	/* Fields to help us manage our entries in the hash tables. */
1215 	struct hlist_node node;
1216 	int hashent;
1217 
1218 	/* Runtime type information.  What kind of endpoint is this? */
1219 	enum sctp_endpoint_type type;
1220 
1221 	/* Some fields to help us manage this object.
1222 	 *   refcnt   - Reference count access to this object.
1223 	 *   dead     - Do not attempt to use this object.
1224 	 */
1225 	refcount_t    refcnt;
1226 	bool	    dead;
1227 
1228 	/* What socket does this endpoint belong to?  */
1229 	struct sock *sk;
1230 
1231 	/* This is where we receive inbound chunks.  */
1232 	struct sctp_inq	  inqueue;
1233 
1234 	/* This substructure includes the defining parameters of the
1235 	 * endpoint:
1236 	 * bind_addr.port is our shared port number.
1237 	 * bind_addr.address_list is our set of local IP addresses.
1238 	 */
1239 	struct sctp_bind_addr bind_addr;
1240 };
1241 
1242 
1243 /* RFC Section 1.4 Key Terms
1244  *
1245  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1246  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1247  *   combination of a set of eligible destination transport addresses to
1248  *   which SCTP packets can be sent and a set of eligible source
1249  *   transport addresses from which SCTP packets can be received.
1250  *   All transport addresses used by an SCTP endpoint must use the
1251  *   same port number, but can use multiple IP addresses. A transport
1252  *   address used by an SCTP endpoint must not be used by another
1253  *   SCTP endpoint. In other words, a transport address is unique
1254  *   to an SCTP endpoint.
1255  *
1256  * From an implementation perspective, each socket has one of these.
1257  * A TCP-style socket will have exactly one association on one of
1258  * these.  An UDP-style socket will have multiple associations hanging
1259  * off one of these.
1260  */
1261 
1262 struct sctp_endpoint {
1263 	/* Common substructure for endpoint and association. */
1264 	struct sctp_ep_common base;
1265 
1266 	/* Associations: A list of current associations and mappings
1267 	 *	      to the data consumers for each association. This
1268 	 *	      may be in the form of a hash table or other
1269 	 *	      implementation dependent structure. The data
1270 	 *	      consumers may be process identification
1271 	 *	      information such as file descriptors, named pipe
1272 	 *	      pointer, or table pointers dependent on how SCTP
1273 	 *	      is implemented.
1274 	 */
1275 	/* This is really a list of struct sctp_association entries. */
1276 	struct list_head asocs;
1277 
1278 	/* Secret Key: A secret key used by this endpoint to compute
1279 	 *	      the MAC.	This SHOULD be a cryptographic quality
1280 	 *	      random number with a sufficient length.
1281 	 *	      Discussion in [RFC1750] can be helpful in
1282 	 *	      selection of the key.
1283 	 */
1284 	__u8 secret_key[SCTP_SECRET_SIZE];
1285 
1286  	/* digest:  This is a digest of the sctp cookie.  This field is
1287  	 * 	    only used on the receive path when we try to validate
1288  	 * 	    that the cookie has not been tampered with.  We put
1289  	 * 	    this here so we pre-allocate this once and can re-use
1290  	 * 	    on every receive.
1291  	 */
1292  	__u8 *digest;
1293 
1294 	/* sendbuf acct. policy.	*/
1295 	__u32 sndbuf_policy;
1296 
1297 	/* rcvbuf acct. policy.	*/
1298 	__u32 rcvbuf_policy;
1299 
1300 	/* SCTP AUTH: array of the HMACs that will be allocated
1301 	 * we need this per association so that we don't serialize
1302 	 */
1303 	struct crypto_shash **auth_hmacs;
1304 
1305 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1306 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1307 
1308 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1309 	struct sctp_chunks_param *auth_chunk_list;
1310 
1311 	/* SCTP-AUTH: endpoint shared keys */
1312 	struct list_head endpoint_shared_keys;
1313 	__u16 active_key_id;
1314 	__u8  auth_enable:1,
1315 	      prsctp_enable:1,
1316 	      reconf_enable:1;
1317 
1318 	__u8  strreset_enable;
1319 };
1320 
1321 /* Recover the outter endpoint structure. */
1322 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1323 {
1324 	struct sctp_endpoint *ep;
1325 
1326 	ep = container_of(base, struct sctp_endpoint, base);
1327 	return ep;
1328 }
1329 
1330 /* These are function signatures for manipulating endpoints.  */
1331 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1332 void sctp_endpoint_free(struct sctp_endpoint *);
1333 void sctp_endpoint_put(struct sctp_endpoint *);
1334 void sctp_endpoint_hold(struct sctp_endpoint *);
1335 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1336 struct sctp_association *sctp_endpoint_lookup_assoc(
1337 	const struct sctp_endpoint *ep,
1338 	const union sctp_addr *paddr,
1339 	struct sctp_transport **);
1340 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1341 				const union sctp_addr *);
1342 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1343 					struct net *, const union sctp_addr *);
1344 int sctp_has_association(struct net *net, const union sctp_addr *laddr,
1345 			 const union sctp_addr *paddr);
1346 
1347 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1348 		     const struct sctp_association *asoc,
1349 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1350 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1351 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1352 		      const union sctp_addr *peer,
1353 		      struct sctp_init_chunk *init, gfp_t gfp);
1354 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1355 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1356 
1357 struct sctp_inithdr_host {
1358 	__u32 init_tag;
1359 	__u32 a_rwnd;
1360 	__u16 num_outbound_streams;
1361 	__u16 num_inbound_streams;
1362 	__u32 initial_tsn;
1363 };
1364 
1365 struct sctp_stream_priorities {
1366 	/* List of priorities scheduled */
1367 	struct list_head prio_sched;
1368 	/* List of streams scheduled */
1369 	struct list_head active;
1370 	/* The next stream stream in line */
1371 	struct sctp_stream_out_ext *next;
1372 	__u16 prio;
1373 };
1374 
1375 struct sctp_stream_out_ext {
1376 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1377 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1378 	struct list_head outq; /* chunks enqueued by this stream */
1379 	union {
1380 		struct {
1381 			/* Scheduled streams list */
1382 			struct list_head prio_list;
1383 			struct sctp_stream_priorities *prio_head;
1384 		};
1385 		/* Fields used by RR scheduler */
1386 		struct {
1387 			struct list_head rr_list;
1388 		};
1389 	};
1390 };
1391 
1392 struct sctp_stream_out {
1393 	union {
1394 		__u32 mid;
1395 		__u16 ssn;
1396 	};
1397 	__u32 mid_uo;
1398 	struct sctp_stream_out_ext *ext;
1399 	__u8 state;
1400 };
1401 
1402 struct sctp_stream_in {
1403 	union {
1404 		__u32 mid;
1405 		__u16 ssn;
1406 	};
1407 	__u32 mid_uo;
1408 	__u32 fsn;
1409 	__u32 fsn_uo;
1410 	char pd_mode;
1411 	char pd_mode_uo;
1412 };
1413 
1414 struct sctp_stream {
1415 	struct sctp_stream_out *out;
1416 	struct sctp_stream_in *in;
1417 	__u16 outcnt;
1418 	__u16 incnt;
1419 	/* Current stream being sent, if any */
1420 	struct sctp_stream_out *out_curr;
1421 	union {
1422 		/* Fields used by priority scheduler */
1423 		struct {
1424 			/* List of priorities scheduled */
1425 			struct list_head prio_list;
1426 		};
1427 		/* Fields used by RR scheduler */
1428 		struct {
1429 			/* List of streams scheduled */
1430 			struct list_head rr_list;
1431 			/* The next stream stream in line */
1432 			struct sctp_stream_out_ext *rr_next;
1433 		};
1434 	};
1435 	struct sctp_stream_interleave *si;
1436 };
1437 
1438 #define SCTP_STREAM_CLOSED		0x00
1439 #define SCTP_STREAM_OPEN		0x01
1440 
1441 static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1442 {
1443 	return stream->si->data_chunk_len;
1444 }
1445 
1446 static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1447 {
1448 	return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1449 }
1450 
1451 static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1452 {
1453 	return stream->si->ftsn_chunk_len;
1454 }
1455 
1456 static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1457 {
1458 	return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1459 }
1460 
1461 /* SCTP_GET_ASSOC_STATS counters */
1462 struct sctp_priv_assoc_stats {
1463 	/* Maximum observed rto in the association during subsequent
1464 	 * observations. Value is set to 0 if no RTO measurement took place
1465 	 * The transport where the max_rto was observed is returned in
1466 	 * obs_rto_ipaddr
1467 	 */
1468 	struct sockaddr_storage obs_rto_ipaddr;
1469 	__u64 max_obs_rto;
1470 	/* Total In and Out SACKs received and sent */
1471 	__u64 isacks;
1472 	__u64 osacks;
1473 	/* Total In and Out packets received and sent */
1474 	__u64 opackets;
1475 	__u64 ipackets;
1476 	/* Total retransmitted chunks */
1477 	__u64 rtxchunks;
1478 	/* TSN received > next expected */
1479 	__u64 outofseqtsns;
1480 	/* Duplicate Chunks received */
1481 	__u64 idupchunks;
1482 	/* Gap Ack Blocks received */
1483 	__u64 gapcnt;
1484 	/* Unordered data chunks sent and received */
1485 	__u64 ouodchunks;
1486 	__u64 iuodchunks;
1487 	/* Ordered data chunks sent and received */
1488 	__u64 oodchunks;
1489 	__u64 iodchunks;
1490 	/* Control chunks sent and received */
1491 	__u64 octrlchunks;
1492 	__u64 ictrlchunks;
1493 };
1494 
1495 /* RFC2960
1496  *
1497  * 12. Recommended Transmission Control Block (TCB) Parameters
1498  *
1499  * This section details a recommended set of parameters that should
1500  * be contained within the TCB for an implementation. This section is
1501  * for illustrative purposes and should not be deemed as requirements
1502  * on an implementation or as an exhaustive list of all parameters
1503  * inside an SCTP TCB. Each implementation may need its own additional
1504  * parameters for optimization.
1505  */
1506 
1507 
1508 /* Here we have information about each individual association. */
1509 struct sctp_association {
1510 
1511 	/* A base structure common to endpoint and association.
1512 	 * In this context, it represents the associations's view
1513 	 * of the local endpoint of the association.
1514 	 */
1515 	struct sctp_ep_common base;
1516 
1517 	/* Associations on the same socket. */
1518 	struct list_head asocs;
1519 
1520 	/* association id. */
1521 	sctp_assoc_t assoc_id;
1522 
1523 	/* This is our parent endpoint.	 */
1524 	struct sctp_endpoint *ep;
1525 
1526 	/* These are those association elements needed in the cookie.  */
1527 	struct sctp_cookie c;
1528 
1529 	/* This is all information about our peer.  */
1530 	struct {
1531 		/* transport_addr_list
1532 		 *
1533 		 * Peer	       : A list of SCTP transport addresses that the
1534 		 * Transport   : peer is bound to. This information is derived
1535 		 * Address     : from the INIT or INIT ACK and is used to
1536 		 * List	       : associate an inbound packet with a given
1537 		 *	       : association. Normally this information is
1538 		 *	       : hashed or keyed for quick lookup and access
1539 		 *	       : of the TCB.
1540 		 *	       : The list is also initialized with the list
1541 		 *	       : of addresses passed with the sctp_connectx()
1542 		 *	       : call.
1543 		 *
1544 		 * It is a list of SCTP_transport's.
1545 		 */
1546 		struct list_head transport_addr_list;
1547 
1548 		/* rwnd
1549 		 *
1550 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1551 		 */
1552 		__u32 rwnd;
1553 
1554 		/* transport_count
1555 		 *
1556 		 * Peer        : A count of the number of peer addresses
1557 		 * Transport   : in the Peer Transport Address List.
1558 		 * Address     :
1559 		 * Count       :
1560 		 */
1561 		__u16 transport_count;
1562 
1563 		/* port
1564 		 *   The transport layer port number.
1565 		 */
1566 		__u16 port;
1567 
1568 		/* primary_path
1569 		 *
1570 		 * Primary     : This is the current primary destination
1571 		 * Path	       : transport address of the peer endpoint.  It
1572 		 *	       : may also specify a source transport address
1573 		 *	       : on this endpoint.
1574 		 *
1575 		 * All of these paths live on transport_addr_list.
1576 		 *
1577 		 * At the bakeoffs, we discovered that the intent of
1578 		 * primaryPath is that it only changes when the ULP
1579 		 * asks to have it changed.  We add the activePath to
1580 		 * designate the connection we are currently using to
1581 		 * transmit new data and most control chunks.
1582 		 */
1583 		struct sctp_transport *primary_path;
1584 
1585 		/* Cache the primary path address here, when we
1586 		 * need a an address for msg_name.
1587 		 */
1588 		union sctp_addr primary_addr;
1589 
1590 		/* active_path
1591 		 *   The path that we are currently using to
1592 		 *   transmit new data and most control chunks.
1593 		 */
1594 		struct sctp_transport *active_path;
1595 
1596 		/* retran_path
1597 		 *
1598 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1599 		 * ...
1600 		 * Furthermore, when its peer is multi-homed, an
1601 		 * endpoint SHOULD try to retransmit a chunk to an
1602 		 * active destination transport address that is
1603 		 * different from the last destination address to
1604 		 * which the DATA chunk was sent.
1605 		 */
1606 		struct sctp_transport *retran_path;
1607 
1608 		/* Pointer to last transport I have sent on.  */
1609 		struct sctp_transport *last_sent_to;
1610 
1611 		/* This is the last transport I have received DATA on.	*/
1612 		struct sctp_transport *last_data_from;
1613 
1614 		/*
1615 		 * Mapping  An array of bits or bytes indicating which out of
1616 		 * Array    order TSN's have been received (relative to the
1617 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1618 		 *	    order packets have been received, this array
1619 		 *	    will be set to all zero. This structure may be
1620 		 *	    in the form of a circular buffer or bit array.
1621 		 *
1622 		 * Last Rcvd   : This is the last TSN received in
1623 		 * TSN	       : sequence. This value is set initially by
1624 		 *	       : taking the peer's Initial TSN, received in
1625 		 *	       : the INIT or INIT ACK chunk, and subtracting
1626 		 *	       : one from it.
1627 		 *
1628 		 * Throughout most of the specification this is called the
1629 		 * "Cumulative TSN ACK Point".	In this case, we
1630 		 * ignore the advice in 12.2 in favour of the term
1631 		 * used in the bulk of the text.  This value is hidden
1632 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1633 		 */
1634 		struct sctp_tsnmap tsn_map;
1635 
1636 		/* This mask is used to disable sending the ASCONF chunk
1637 		 * with specified parameter to peer.
1638 		 */
1639 		__be16 addip_disabled_mask;
1640 
1641 		/* These are capabilities which our peer advertised.  */
1642 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1643 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1644 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1645 			hostname_address:1, /* Peer understands DNS addresses? */
1646 			asconf_capable:1,   /* Does peer support ADDIP? */
1647 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1648 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1649 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1650 
1651 		/* sack_needed : This flag indicates if the next received
1652 		 *             : packet is to be responded to with a
1653 		 *             : SACK. This is initialized to 0.  When a packet
1654 		 *             : is received sack_cnt is incremented. If this value
1655 		 *             : reaches 2 or more, a SACK is sent and the
1656 		 *             : value is reset to 0. Note: This is used only
1657 		 *             : when no DATA chunks are received out of
1658 		 *             : order.  When DATA chunks are out of order,
1659 		 *             : SACK's are not delayed (see Section 6).
1660 		 */
1661 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1662 			sack_generation:1,
1663 			zero_window_announced:1;
1664 		__u32	sack_cnt;
1665 
1666 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1667 
1668 		struct sctp_inithdr_host i;
1669 		void *cookie;
1670 		int cookie_len;
1671 
1672 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1673 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1674 		 * Initial TSN Value minus 1
1675 		 */
1676 		__u32 addip_serial;
1677 
1678 		/* SCTP-AUTH: We need to know pears random number, hmac list
1679 		 * and authenticated chunk list.  All that is part of the
1680 		 * cookie and these are just pointers to those locations
1681 		 */
1682 		struct sctp_random_param *peer_random;
1683 		struct sctp_chunks_param *peer_chunks;
1684 		struct sctp_hmac_algo_param *peer_hmacs;
1685 	} peer;
1686 
1687 	/* State       : A state variable indicating what state the
1688 	 *	       : association is in, i.e. COOKIE-WAIT,
1689 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1690 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1691 	 *
1692 	 *		Note: No "CLOSED" state is illustrated since if a
1693 	 *		association is "CLOSED" its TCB SHOULD be removed.
1694 	 *
1695 	 *		In this implementation we DO have a CLOSED
1696 	 *		state which is used during initiation and shutdown.
1697 	 *
1698 	 *		State takes values from SCTP_STATE_*.
1699 	 */
1700 	enum sctp_state state;
1701 
1702 	/* Overall     : The overall association error count.
1703 	 * Error Count : [Clear this any time I get something.]
1704 	 */
1705 	int overall_error_count;
1706 
1707 	/* The cookie life I award for any cookie.  */
1708 	ktime_t cookie_life;
1709 
1710 	/* These are the association's initial, max, and min RTO values.
1711 	 * These values will be initialized by system defaults, but can
1712 	 * be modified via the SCTP_RTOINFO socket option.
1713 	 */
1714 	unsigned long rto_initial;
1715 	unsigned long rto_max;
1716 	unsigned long rto_min;
1717 
1718 	/* Maximum number of new data packets that can be sent in a burst.  */
1719 	int max_burst;
1720 
1721 	/* This is the max_retrans value for the association.  This value will
1722 	 * be initialized initialized from system defaults, but can be
1723 	 * modified by the SCTP_ASSOCINFO socket option.
1724 	 */
1725 	int max_retrans;
1726 
1727 	/* This is the partially failed retrans value for the transport
1728 	 * and will be initialized from the assocs value.  This can be
1729 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1730 	 */
1731 	int pf_retrans;
1732 
1733 	/* Maximum number of times the endpoint will retransmit INIT  */
1734 	__u16 max_init_attempts;
1735 
1736 	/* How many times have we resent an INIT? */
1737 	__u16 init_retries;
1738 
1739 	/* The largest timeout or RTO value to use in attempting an INIT */
1740 	unsigned long max_init_timeo;
1741 
1742 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1743 	 * the destination address every heartbeat interval. This value
1744 	 * will be inherited by all new transports.
1745 	 */
1746 	unsigned long hbinterval;
1747 
1748 	/* This is the max_retrans value for new transports in the
1749 	 * association.
1750 	 */
1751 	__u16 pathmaxrxt;
1752 
1753 	/* Flag that path mtu update is pending */
1754 	__u8   pmtu_pending;
1755 
1756 	/* Association : The smallest PMTU discovered for all of the
1757 	 * PMTU	       : peer's transport addresses.
1758 	 */
1759 	__u32 pathmtu;
1760 
1761 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1762 	__u32 param_flags;
1763 
1764 	__u32 sackfreq;
1765 	/* SACK delay timeout */
1766 	unsigned long sackdelay;
1767 
1768 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1769 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1770 
1771 	/* Transport to which SHUTDOWN chunk was last sent.  */
1772 	struct sctp_transport *shutdown_last_sent_to;
1773 
1774 	/* Transport to which INIT chunk was last sent.  */
1775 	struct sctp_transport *init_last_sent_to;
1776 
1777 	/* How many times have we resent a SHUTDOWN */
1778 	int shutdown_retries;
1779 
1780 	/* Next TSN    : The next TSN number to be assigned to a new
1781 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1782 	 *	       : ACK chunk to the peer and incremented each
1783 	 *	       : time a DATA chunk is assigned a TSN
1784 	 *	       : (normally just prior to transmit or during
1785 	 *	       : fragmentation).
1786 	 */
1787 	__u32 next_tsn;
1788 
1789 	/*
1790 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1791 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1792 	 *	       : received in the INIT or INIT ACK chunk, and
1793 	 *	       : subtracting one from it.
1794 	 *
1795 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1796 	 */
1797 
1798 	__u32 ctsn_ack_point;
1799 
1800 	/* PR-SCTP Advanced.Peer.Ack.Point */
1801 	__u32 adv_peer_ack_point;
1802 
1803 	/* Highest TSN that is acknowledged by incoming SACKs. */
1804 	__u32 highest_sacked;
1805 
1806 	/* TSN marking the fast recovery exit point */
1807 	__u32 fast_recovery_exit;
1808 
1809 	/* Flag to track the current fast recovery state */
1810 	__u8 fast_recovery;
1811 
1812 	/* The number of unacknowledged data chunks.  Reported through
1813 	 * the SCTP_STATUS sockopt.
1814 	 */
1815 	__u16 unack_data;
1816 
1817 	/* The total number of data chunks that we've had to retransmit
1818 	 * as the result of a T3 timer expiration
1819 	 */
1820 	__u32 rtx_data_chunks;
1821 
1822 	/* This is the association's receive buffer space.  This value is used
1823 	 * to set a_rwnd field in an INIT or a SACK chunk.
1824 	 */
1825 	__u32 rwnd;
1826 
1827 	/* This is the last advertised value of rwnd over a SACK chunk. */
1828 	__u32 a_rwnd;
1829 
1830 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1831 	 * to slop over a maximum of the association's frag_point.
1832 	 */
1833 	__u32 rwnd_over;
1834 
1835 	/* Keeps treack of rwnd pressure.  This happens when we have
1836 	 * a window, but not recevie buffer (i.e small packets).  This one
1837 	 * is releases slowly (1 PMTU at a time ).
1838 	 */
1839 	__u32 rwnd_press;
1840 
1841 	/* This is the sndbuf size in use for the association.
1842 	 * This corresponds to the sndbuf size for the association,
1843 	 * as specified in the sk->sndbuf.
1844 	 */
1845 	int sndbuf_used;
1846 
1847 	/* This is the amount of memory that this association has allocated
1848 	 * in the receive path at any given time.
1849 	 */
1850 	atomic_t rmem_alloc;
1851 
1852 	/* This is the wait queue head for send requests waiting on
1853 	 * the association sndbuf space.
1854 	 */
1855 	wait_queue_head_t	wait;
1856 
1857 	/* The message size at which SCTP fragmentation will occur. */
1858 	__u32 frag_point;
1859 	__u32 user_frag;
1860 
1861 	/* Counter used to count INIT errors. */
1862 	int init_err_counter;
1863 
1864 	/* Count the number of INIT cycles (for doubling timeout). */
1865 	int init_cycle;
1866 
1867 	/* Default send parameters. */
1868 	__u16 default_stream;
1869 	__u16 default_flags;
1870 	__u32 default_ppid;
1871 	__u32 default_context;
1872 	__u32 default_timetolive;
1873 
1874 	/* Default receive parameters */
1875 	__u32 default_rcv_context;
1876 
1877 	/* Stream arrays */
1878 	struct sctp_stream stream;
1879 
1880 	/* All outbound chunks go through this structure.  */
1881 	struct sctp_outq outqueue;
1882 
1883 	/* A smart pipe that will handle reordering and fragmentation,
1884 	 * as well as handle passing events up to the ULP.
1885 	 */
1886 	struct sctp_ulpq ulpq;
1887 
1888 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1889 	__u32 last_ecne_tsn;
1890 
1891 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1892 	__u32 last_cwr_tsn;
1893 
1894 	/* How many duplicated TSNs have we seen?  */
1895 	int numduptsns;
1896 
1897 	/* These are to support
1898 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1899 	 *  and Enforcement of Flow and Message Limits"
1900 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1901 	 * or "ADDIP" for short.
1902 	 */
1903 
1904 
1905 
1906 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1907 	 *
1908 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1909 	 * unacknowledged at any one time.  If a sender, after sending
1910 	 * an ASCONF chunk, decides it needs to transfer another
1911 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1912 	 * returns from the previous ASCONF Chunk before sending a
1913 	 * subsequent ASCONF. Note this restriction binds each side,
1914 	 * so at any time two ASCONF may be in-transit on any given
1915 	 * association (one sent from each endpoint).
1916 	 *
1917 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1918 	 * not have an ASCONF in flight, this is NULL.]
1919 	 */
1920 	struct sctp_chunk *addip_last_asconf;
1921 
1922 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1923 	 *
1924 	 * This is needed to implement itmes E1 - E4 of the updated
1925 	 * spec.  Here is the justification:
1926 	 *
1927 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1928 	 * we now need the ability to cache multiple ACKs.  The section
1929 	 * describes in detail how they are cached and cleaned up.
1930 	 */
1931 	struct list_head asconf_ack_list;
1932 
1933 	/* These ASCONF chunks are waiting to be sent.
1934 	 *
1935 	 * These chunaks can't be pushed to outqueue until receiving
1936 	 * ASCONF_ACK for the previous ASCONF indicated by
1937 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1938 	 * is in flight at any time.
1939 	 *
1940 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1941 	 *
1942 	 * In defining the ASCONF Chunk transfer procedures, it is
1943 	 * essential that these transfers MUST NOT cause congestion
1944 	 * within the network.	To achieve this, we place these
1945 	 * restrictions on the transfer of ASCONF Chunks:
1946 	 *
1947 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1948 	 * unacknowledged at any one time.  If a sender, after sending
1949 	 * an ASCONF chunk, decides it needs to transfer another
1950 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1951 	 * returns from the previous ASCONF Chunk before sending a
1952 	 * subsequent ASCONF. Note this restriction binds each side,
1953 	 * so at any time two ASCONF may be in-transit on any given
1954 	 * association (one sent from each endpoint).
1955 	 *
1956 	 *
1957 	 * [I really think this is EXACTLY the sort of intelligence
1958 	 *  which already resides in sctp_outq.	 Please move this
1959 	 *  queue and its supporting logic down there.	--piggy]
1960 	 */
1961 	struct list_head addip_chunk_list;
1962 
1963 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1964 	 *
1965 	 * A2) A serial number should be assigned to the Chunk. The
1966 	 * serial number SHOULD be a monotonically increasing
1967 	 * number. The serial number SHOULD be initialized at
1968 	 * the start of the association to the same value as the
1969 	 * Initial TSN and every time a new ASCONF chunk is created
1970 	 * it is incremented by one after assigning the serial number
1971 	 * to the newly created chunk.
1972 	 *
1973 	 * ADDIP
1974 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1975 	 *
1976 	 * Serial Number : 32 bits (unsigned integer)
1977 	 *
1978 	 * This value represents a Serial Number for the ASCONF
1979 	 * Chunk. The valid range of Serial Number is from 0 to
1980 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1981 	 * after reaching 4294967295.
1982 	 */
1983 	__u32 addip_serial;
1984 	int src_out_of_asoc_ok;
1985 	union sctp_addr *asconf_addr_del_pending;
1986 	struct sctp_transport *new_transport;
1987 
1988 	/* SCTP AUTH: list of the endpoint shared keys.  These
1989 	 * keys are provided out of band by the user applicaton
1990 	 * and can't change during the lifetime of the association
1991 	 */
1992 	struct list_head endpoint_shared_keys;
1993 
1994 	/* SCTP AUTH:
1995 	 * The current generated assocaition shared key (secret)
1996 	 */
1997 	struct sctp_auth_bytes *asoc_shared_key;
1998 
1999 	/* SCTP AUTH: hmac id of the first peer requested algorithm
2000 	 * that we support.
2001 	 */
2002 	__u16 default_hmac_id;
2003 
2004 	__u16 active_key_id;
2005 
2006 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
2007 	     temp:1,		/* Is it a temporary association? */
2008 	     force_delay:1,
2009 	     intl_enable:1,
2010 	     prsctp_enable:1,
2011 	     reconf_enable:1;
2012 
2013 	__u8 strreset_enable;
2014 	__u8 strreset_outstanding; /* request param count on the fly */
2015 
2016 	__u32 strreset_outseq; /* Update after receiving response */
2017 	__u32 strreset_inseq; /* Update after receiving request */
2018 	__u32 strreset_result[2]; /* save the results of last 2 responses */
2019 
2020 	struct sctp_chunk *strreset_chunk; /* save request chunk */
2021 
2022 	struct sctp_priv_assoc_stats stats;
2023 
2024 	int sent_cnt_removable;
2025 
2026 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2027 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2028 };
2029 
2030 
2031 /* An eyecatcher for determining if we are really looking at an
2032  * association data structure.
2033  */
2034 enum {
2035 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
2036 };
2037 
2038 /* Recover the outter association structure. */
2039 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2040 {
2041 	struct sctp_association *asoc;
2042 
2043 	asoc = container_of(base, struct sctp_association, base);
2044 	return asoc;
2045 }
2046 
2047 /* These are function signatures for manipulating associations.	 */
2048 
2049 
2050 struct sctp_association *
2051 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2052 		     enum sctp_scope scope, gfp_t gfp);
2053 void sctp_association_free(struct sctp_association *);
2054 void sctp_association_put(struct sctp_association *);
2055 void sctp_association_hold(struct sctp_association *);
2056 
2057 struct sctp_transport *sctp_assoc_choose_alter_transport(
2058 	struct sctp_association *, struct sctp_transport *);
2059 void sctp_assoc_update_retran_path(struct sctp_association *);
2060 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2061 					  const union sctp_addr *);
2062 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2063 			    const union sctp_addr *laddr);
2064 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2065 				     const union sctp_addr *address,
2066 				     const gfp_t gfp,
2067 				     const int peer_state);
2068 void sctp_assoc_del_peer(struct sctp_association *asoc,
2069 			 const union sctp_addr *addr);
2070 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2071 			 struct sctp_transport *peer);
2072 void sctp_assoc_control_transport(struct sctp_association *asoc,
2073 				  struct sctp_transport *transport,
2074 				  enum sctp_transport_cmd command,
2075 				  sctp_sn_error_t error);
2076 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2077 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
2078 					   struct net *,
2079 					   const union sctp_addr *,
2080 					   const union sctp_addr *);
2081 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2082 int sctp_assoc_update(struct sctp_association *old,
2083 		      struct sctp_association *new);
2084 
2085 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2086 
2087 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2088 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2089 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2090 void sctp_assoc_set_primary(struct sctp_association *,
2091 			    struct sctp_transport *);
2092 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2093 				    struct sctp_transport *);
2094 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2095 				     enum sctp_scope scope, gfp_t gfp);
2096 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2097 					 struct sctp_cookie*,
2098 					 gfp_t gfp);
2099 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2100 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2101 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2102 					const struct sctp_association *asoc,
2103 					__be32 serial);
2104 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2105 
2106 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2107 			const union sctp_addr *ss2);
2108 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2109 
2110 /* A convenience structure to parse out SCTP specific CMSGs. */
2111 struct sctp_cmsgs {
2112 	struct sctp_initmsg *init;
2113 	struct sctp_sndrcvinfo *srinfo;
2114 	struct sctp_sndinfo *sinfo;
2115 };
2116 
2117 /* Structure for tracking memory objects */
2118 struct sctp_dbg_objcnt_entry {
2119 	char *label;
2120 	atomic_t *counter;
2121 };
2122 
2123 #endif /* __sctp_structs_h__ */
2124