xref: /openbmc/linux/include/net/sctp/structs.h (revision d9e32672)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* SCTP kernel implementation
3  * (C) Copyright IBM Corp. 2001, 2004
4  * Copyright (c) 1999-2000 Cisco, Inc.
5  * Copyright (c) 1999-2001 Motorola, Inc.
6  * Copyright (c) 2001 Intel Corp.
7  *
8  * This file is part of the SCTP kernel implementation
9  *
10  * Please send any bug reports or fixes you make to the
11  * email addresses:
12  *    lksctp developers <linux-sctp@vger.kernel.org>
13  *
14  * Written or modified by:
15  *    Randall Stewart	    <randall@sctp.chicago.il.us>
16  *    Ken Morneau	    <kmorneau@cisco.com>
17  *    Qiaobing Xie	    <qxie1@email.mot.com>
18  *    La Monte H.P. Yarroll <piggy@acm.org>
19  *    Karl Knutson	    <karl@athena.chicago.il.us>
20  *    Jon Grimm		    <jgrimm@us.ibm.com>
21  *    Xingang Guo	    <xingang.guo@intel.com>
22  *    Hui Huang		    <hui.huang@nokia.com>
23  *    Sridhar Samudrala	    <sri@us.ibm.com>
24  *    Daisy Chang	    <daisyc@us.ibm.com>
25  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
26  *    Ardelle Fan	    <ardelle.fan@intel.com>
27  *    Ryan Layer	    <rmlayer@us.ibm.com>
28  *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
29  *    Kevin Gao             <kevin.gao@intel.com>
30  */
31 
32 #ifndef __sctp_structs_h__
33 #define __sctp_structs_h__
34 
35 #include <linux/ktime.h>
36 #include <linux/generic-radix-tree.h>
37 #include <linux/rhashtable-types.h>
38 #include <linux/socket.h>	/* linux/in.h needs this!!    */
39 #include <linux/in.h>		/* We get struct sockaddr_in. */
40 #include <linux/in6.h>		/* We get struct in6_addr     */
41 #include <linux/ipv6.h>
42 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
43 #include <linux/atomic.h>		/* This gets us atomic counters.  */
44 #include <linux/skbuff.h>	/* We need sk_buff_head. */
45 #include <linux/workqueue.h>	/* We need tq_struct.	 */
46 #include <linux/sctp.h>		/* We need sctp* header structs.  */
47 #include <net/sctp/auth.h>	/* We need auth specific structs */
48 #include <net/ip.h>		/* For inet_skb_parm */
49 
50 /* A convenience structure for handling sockaddr structures.
51  * We should wean ourselves off this.
52  */
53 union sctp_addr {
54 	struct sockaddr_in v4;
55 	struct sockaddr_in6 v6;
56 	struct sockaddr sa;
57 };
58 
59 /* Forward declarations for data structures. */
60 struct sctp_globals;
61 struct sctp_endpoint;
62 struct sctp_association;
63 struct sctp_transport;
64 struct sctp_packet;
65 struct sctp_chunk;
66 struct sctp_inq;
67 struct sctp_outq;
68 struct sctp_bind_addr;
69 struct sctp_ulpq;
70 struct sctp_ep_common;
71 struct crypto_shash;
72 struct sctp_stream;
73 
74 
75 #include <net/sctp/tsnmap.h>
76 #include <net/sctp/ulpevent.h>
77 #include <net/sctp/ulpqueue.h>
78 #include <net/sctp/stream_interleave.h>
79 
80 /* Structures useful for managing bind/connect. */
81 
82 struct sctp_bind_bucket {
83 	unsigned short	port;
84 	signed char	fastreuse;
85 	signed char	fastreuseport;
86 	kuid_t		fastuid;
87 	struct hlist_node	node;
88 	struct hlist_head	owner;
89 	struct net	*net;
90 };
91 
92 struct sctp_bind_hashbucket {
93 	spinlock_t	lock;
94 	struct hlist_head	chain;
95 };
96 
97 /* Used for hashing all associations.  */
98 struct sctp_hashbucket {
99 	rwlock_t	lock;
100 	struct hlist_head	chain;
101 } __attribute__((__aligned__(8)));
102 
103 
104 /* The SCTP globals structure. */
105 extern struct sctp_globals {
106 	/* This is a list of groups of functions for each address
107 	 * family that we support.
108 	 */
109 	struct list_head address_families;
110 
111 	/* This is the hash of all endpoints. */
112 	struct sctp_hashbucket *ep_hashtable;
113 	/* This is the sctp port control hash.	*/
114 	struct sctp_bind_hashbucket *port_hashtable;
115 	/* This is the hash of all transports. */
116 	struct rhltable transport_hashtable;
117 
118 	/* Sizes of above hashtables. */
119 	int ep_hashsize;
120 	int port_hashsize;
121 
122 	/* Default initialization values to be applied to new associations. */
123 	__u16 max_instreams;
124 	__u16 max_outstreams;
125 
126 	/* Flag to indicate whether computing and verifying checksum
127 	 * is disabled. */
128         bool checksum_disable;
129 } sctp_globals;
130 
131 #define sctp_max_instreams		(sctp_globals.max_instreams)
132 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
133 #define sctp_address_families		(sctp_globals.address_families)
134 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
135 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
136 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
137 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
138 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
139 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
140 
141 /* SCTP Socket type: UDP or TCP style. */
142 enum sctp_socket_type {
143 	SCTP_SOCKET_UDP = 0,
144 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
145 	SCTP_SOCKET_TCP
146 };
147 
148 /* Per socket SCTP information. */
149 struct sctp_sock {
150 	/* inet_sock has to be the first member of sctp_sock */
151 	struct inet_sock inet;
152 	/* What kind of a socket is this? */
153 	enum sctp_socket_type type;
154 
155 	/* PF_ family specific functions.  */
156 	struct sctp_pf *pf;
157 
158 	/* Access to HMAC transform. */
159 	struct crypto_shash *hmac;
160 	char *sctp_hmac_alg;
161 
162 	/* What is our base endpointer? */
163 	struct sctp_endpoint *ep;
164 
165 	struct sctp_bind_bucket *bind_hash;
166 	/* Various Socket Options.  */
167 	__u16 default_stream;
168 	__u32 default_ppid;
169 	__u16 default_flags;
170 	__u32 default_context;
171 	__u32 default_timetolive;
172 	__u32 default_rcv_context;
173 	int max_burst;
174 
175 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
176 	 * the destination address every heartbeat interval. This value
177 	 * will be inherited by all new associations.
178 	 */
179 	__u32 hbinterval;
180 
181 	/* This is the max_retrans value for new associations. */
182 	__u16 pathmaxrxt;
183 
184 	__u32 flowlabel;
185 	__u8  dscp;
186 
187 	int pf_retrans;
188 
189 	/* The initial Path MTU to use for new associations. */
190 	__u32 pathmtu;
191 
192 	/* The default SACK delay timeout for new associations. */
193 	__u32 sackdelay;
194 	__u32 sackfreq;
195 
196 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
197 	__u32 param_flags;
198 
199 	__u32 default_ss;
200 
201 	struct sctp_rtoinfo rtoinfo;
202 	struct sctp_paddrparams paddrparam;
203 	struct sctp_assocparams assocparams;
204 
205 	/*
206 	 * These two structures must be grouped together for the usercopy
207 	 * whitelist region.
208 	 */
209 	__u16 subscribe;
210 	struct sctp_initmsg initmsg;
211 
212 	int user_frag;
213 
214 	__u32 autoclose;
215 	__u32 adaptation_ind;
216 	__u32 pd_point;
217 	__u16	nodelay:1,
218 		reuse:1,
219 		disable_fragments:1,
220 		v4mapped:1,
221 		frag_interleave:1,
222 		recvrcvinfo:1,
223 		recvnxtinfo:1,
224 		data_ready_signalled:1;
225 
226 	atomic_t pd_mode;
227 	/* Receive to here while partial delivery is in effect. */
228 	struct sk_buff_head pd_lobby;
229 
230 	/* These must be the last fields, as they will skipped on copies,
231 	 * like on accept and peeloff operations
232 	 */
233 	struct list_head auto_asconf_list;
234 	int do_auto_asconf;
235 };
236 
237 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
238 {
239        return (struct sctp_sock *)sk;
240 }
241 
242 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
243 {
244        return (struct sock *)sp;
245 }
246 
247 #if IS_ENABLED(CONFIG_IPV6)
248 struct sctp6_sock {
249        struct sctp_sock  sctp;
250        struct ipv6_pinfo inet6;
251 };
252 #endif /* CONFIG_IPV6 */
253 
254 
255 /* This is our APPLICATION-SPECIFIC state cookie.
256  * THIS IS NOT DICTATED BY THE SPECIFICATION.
257  */
258 /* These are the parts of an association which we send in the cookie.
259  * Most of these are straight out of:
260  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
261  *
262  */
263 
264 struct sctp_cookie {
265 
266 	/* My	       : Tag expected in every inbound packet and sent
267 	 * Verification: in the INIT or INIT ACK chunk.
268 	 * Tag	       :
269 	 */
270 	__u32 my_vtag;
271 
272 	/* Peer's      : Tag expected in every outbound packet except
273 	 * Verification: in the INIT chunk.
274 	 * Tag	       :
275 	 */
276 	__u32 peer_vtag;
277 
278 	/* The rest of these are not from the spec, but really need to
279 	 * be in the cookie.
280 	 */
281 
282 	/* My Tie Tag  : Assist in discovering a restarting association. */
283 	__u32 my_ttag;
284 
285 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
286 	__u32 peer_ttag;
287 
288 	/* When does this cookie expire? */
289 	ktime_t expiration;
290 
291 	/* Number of inbound/outbound streams which are set
292 	 * and negotiated during the INIT process.
293 	 */
294 	__u16 sinit_num_ostreams;
295 	__u16 sinit_max_instreams;
296 
297 	/* This is the first sequence number I used.  */
298 	__u32 initial_tsn;
299 
300 	/* This holds the originating address of the INIT packet.  */
301 	union sctp_addr peer_addr;
302 
303 	/* IG Section 2.35.3
304 	 * Include the source port of the INIT-ACK
305 	 */
306 	__u16		my_port;
307 
308 	__u8 prsctp_capable;
309 
310 	/* Padding for future use */
311 	__u8 padding;
312 
313 	__u32 adaptation_ind;
314 
315 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
316 			 SCTP_AUTH_RANDOM_LENGTH];
317 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
318 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
319 
320 	/* This is a shim for my peer's INIT packet, followed by
321 	 * a copy of the raw address list of the association.
322 	 * The length of the raw address list is saved in the
323 	 * raw_addr_list_len field, which will be used at the time when
324 	 * the association TCB is re-constructed from the cookie.
325 	 */
326 	__u32 raw_addr_list_len;
327 	struct sctp_init_chunk peer_init[0];
328 };
329 
330 
331 /* The format of our cookie that we send to our peer. */
332 struct sctp_signed_cookie {
333 	__u8 signature[SCTP_SECRET_SIZE];
334 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
335 	struct sctp_cookie c;
336 } __packed;
337 
338 /* This is another convenience type to allocate memory for address
339  * params for the maximum size and pass such structures around
340  * internally.
341  */
342 union sctp_addr_param {
343 	struct sctp_paramhdr p;
344 	struct sctp_ipv4addr_param v4;
345 	struct sctp_ipv6addr_param v6;
346 };
347 
348 /* A convenience type to allow walking through the various
349  * parameters and avoid casting all over the place.
350  */
351 union sctp_params {
352 	void *v;
353 	struct sctp_paramhdr *p;
354 	struct sctp_cookie_preserve_param *life;
355 	struct sctp_hostname_param *dns;
356 	struct sctp_cookie_param *cookie;
357 	struct sctp_supported_addrs_param *sat;
358 	struct sctp_ipv4addr_param *v4;
359 	struct sctp_ipv6addr_param *v6;
360 	union sctp_addr_param *addr;
361 	struct sctp_adaptation_ind_param *aind;
362 	struct sctp_supported_ext_param *ext;
363 	struct sctp_random_param *random;
364 	struct sctp_chunks_param *chunks;
365 	struct sctp_hmac_algo_param *hmac_algo;
366 	struct sctp_addip_param *addip;
367 };
368 
369 /* RFC 2960.  Section 3.3.5 Heartbeat.
370  *    Heartbeat Information: variable length
371  *    The Sender-specific Heartbeat Info field should normally include
372  *    information about the sender's current time when this HEARTBEAT
373  *    chunk is sent and the destination transport address to which this
374  *    HEARTBEAT is sent (see Section 8.3).
375  */
376 struct sctp_sender_hb_info {
377 	struct sctp_paramhdr param_hdr;
378 	union sctp_addr daddr;
379 	unsigned long sent_at;
380 	__u64 hb_nonce;
381 };
382 
383 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
384 		     gfp_t gfp);
385 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
386 void sctp_stream_free(struct sctp_stream *stream);
387 void sctp_stream_clear(struct sctp_stream *stream);
388 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
389 
390 /* What is the current SSN number for this stream? */
391 #define sctp_ssn_peek(stream, type, sid) \
392 	(sctp_stream_##type((stream), (sid))->ssn)
393 
394 /* Return the next SSN number for this stream.	*/
395 #define sctp_ssn_next(stream, type, sid) \
396 	(sctp_stream_##type((stream), (sid))->ssn++)
397 
398 /* Skip over this ssn and all below. */
399 #define sctp_ssn_skip(stream, type, sid, ssn) \
400 	(sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
401 
402 /* What is the current MID number for this stream? */
403 #define sctp_mid_peek(stream, type, sid) \
404 	(sctp_stream_##type((stream), (sid))->mid)
405 
406 /* Return the next MID number for this stream.  */
407 #define sctp_mid_next(stream, type, sid) \
408 	(sctp_stream_##type((stream), (sid))->mid++)
409 
410 /* Skip over this mid and all below. */
411 #define sctp_mid_skip(stream, type, sid, mid) \
412 	(sctp_stream_##type((stream), (sid))->mid = mid + 1)
413 
414 /* What is the current MID_uo number for this stream? */
415 #define sctp_mid_uo_peek(stream, type, sid) \
416 	(sctp_stream_##type((stream), (sid))->mid_uo)
417 
418 /* Return the next MID_uo number for this stream.  */
419 #define sctp_mid_uo_next(stream, type, sid) \
420 	(sctp_stream_##type((stream), (sid))->mid_uo++)
421 
422 /*
423  * Pointers to address related SCTP functions.
424  * (i.e. things that depend on the address family.)
425  */
426 struct sctp_af {
427 	int		(*sctp_xmit)	(struct sk_buff *skb,
428 					 struct sctp_transport *);
429 	int		(*setsockopt)	(struct sock *sk,
430 					 int level,
431 					 int optname,
432 					 char __user *optval,
433 					 unsigned int optlen);
434 	int		(*getsockopt)	(struct sock *sk,
435 					 int level,
436 					 int optname,
437 					 char __user *optval,
438 					 int __user *optlen);
439 	int		(*compat_setsockopt)	(struct sock *sk,
440 					 int level,
441 					 int optname,
442 					 char __user *optval,
443 					 unsigned int optlen);
444 	int		(*compat_getsockopt)	(struct sock *sk,
445 					 int level,
446 					 int optname,
447 					 char __user *optval,
448 					 int __user *optlen);
449 	void		(*get_dst)	(struct sctp_transport *t,
450 					 union sctp_addr *saddr,
451 					 struct flowi *fl,
452 					 struct sock *sk);
453 	void		(*get_saddr)	(struct sctp_sock *sk,
454 					 struct sctp_transport *t,
455 					 struct flowi *fl);
456 	void		(*copy_addrlist) (struct list_head *,
457 					  struct net_device *);
458 	int		(*cmp_addr)	(const union sctp_addr *addr1,
459 					 const union sctp_addr *addr2);
460 	void		(*addr_copy)	(union sctp_addr *dst,
461 					 union sctp_addr *src);
462 	void		(*from_skb)	(union sctp_addr *,
463 					 struct sk_buff *skb,
464 					 int saddr);
465 	void		(*from_sk)	(union sctp_addr *,
466 					 struct sock *sk);
467 	void		(*from_addr_param) (union sctp_addr *,
468 					    union sctp_addr_param *,
469 					    __be16 port, int iif);
470 	int		(*to_addr_param) (const union sctp_addr *,
471 					  union sctp_addr_param *);
472 	int		(*addr_valid)	(union sctp_addr *,
473 					 struct sctp_sock *,
474 					 const struct sk_buff *);
475 	enum sctp_scope	(*scope)(union sctp_addr *);
476 	void		(*inaddr_any)	(union sctp_addr *, __be16);
477 	int		(*is_any)	(const union sctp_addr *);
478 	int		(*available)	(union sctp_addr *,
479 					 struct sctp_sock *);
480 	int		(*skb_iif)	(const struct sk_buff *sk);
481 	int		(*is_ce)	(const struct sk_buff *sk);
482 	void		(*seq_dump_addr)(struct seq_file *seq,
483 					 union sctp_addr *addr);
484 	void		(*ecn_capable)(struct sock *sk);
485 	__u16		net_header_len;
486 	int		sockaddr_len;
487 	int		(*ip_options_len)(struct sock *sk);
488 	sa_family_t	sa_family;
489 	struct list_head list;
490 };
491 
492 struct sctp_af *sctp_get_af_specific(sa_family_t);
493 int sctp_register_af(struct sctp_af *);
494 
495 /* Protocol family functions. */
496 struct sctp_pf {
497 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
498 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
499 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
500 	int  (*cmp_addr) (const union sctp_addr *,
501 			  const union sctp_addr *,
502 			  struct sctp_sock *);
503 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
504 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
505 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
506 	struct sock *(*create_accept_sk) (struct sock *sk,
507 					  struct sctp_association *asoc,
508 					  bool kern);
509 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
510 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
511 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
512 	void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
513 	struct sctp_af *af;
514 };
515 
516 
517 /* Structure to track chunk fragments that have been acked, but peer
518  * fragments of the same message have not.
519  */
520 struct sctp_datamsg {
521 	/* Chunks waiting to be submitted to lower layer. */
522 	struct list_head chunks;
523 	/* Reference counting. */
524 	refcount_t refcnt;
525 	/* When is this message no longer interesting to the peer? */
526 	unsigned long expires_at;
527 	/* Did the messenge fail to send? */
528 	int send_error;
529 	u8 send_failed:1,
530 	   can_delay:1,	/* should this message be Nagle delayed */
531 	   abandoned:1;	/* should this message be abandoned */
532 };
533 
534 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
535 					    struct sctp_sndrcvinfo *,
536 					    struct iov_iter *);
537 void sctp_datamsg_free(struct sctp_datamsg *);
538 void sctp_datamsg_put(struct sctp_datamsg *);
539 void sctp_chunk_fail(struct sctp_chunk *, int error);
540 int sctp_chunk_abandoned(struct sctp_chunk *);
541 
542 /* RFC2960 1.4 Key Terms
543  *
544  * o Chunk: A unit of information within an SCTP packet, consisting of
545  * a chunk header and chunk-specific content.
546  *
547  * As a matter of convenience, we remember the SCTP common header for
548  * each chunk as well as a few other header pointers...
549  */
550 struct sctp_chunk {
551 	struct list_head list;
552 
553 	refcount_t refcnt;
554 
555 	/* How many times this chunk have been sent, for prsctp RTX policy */
556 	int sent_count;
557 
558 	union {
559 		/* This is our link to the per-transport transmitted list.  */
560 		struct list_head transmitted_list;
561 		/* List in specific stream outq */
562 		struct list_head stream_list;
563 	};
564 
565 	/* This field is used by chunks that hold fragmented data.
566 	 * For the first fragment this is the list that holds the rest of
567 	 * fragments. For the remaining fragments, this is the link to the
568 	 * frag_list maintained in the first fragment.
569 	 */
570 	struct list_head frag_list;
571 
572 	/* This points to the sk_buff containing the actual data.  */
573 	struct sk_buff *skb;
574 
575 	union {
576 		/* In case of GSO packets, this will store the head one */
577 		struct sk_buff *head_skb;
578 		/* In case of auth enabled, this will point to the shkey */
579 		struct sctp_shared_key *shkey;
580 	};
581 
582 	/* These are the SCTP headers by reverse order in a packet.
583 	 * Note that some of these may happen more than once.  In that
584 	 * case, we point at the "current" one, whatever that means
585 	 * for that level of header.
586 	 */
587 
588 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
589 	union sctp_params param_hdr;
590 	union {
591 		__u8 *v;
592 		struct sctp_datahdr *data_hdr;
593 		struct sctp_inithdr *init_hdr;
594 		struct sctp_sackhdr *sack_hdr;
595 		struct sctp_heartbeathdr *hb_hdr;
596 		struct sctp_sender_hb_info *hbs_hdr;
597 		struct sctp_shutdownhdr *shutdown_hdr;
598 		struct sctp_signed_cookie *cookie_hdr;
599 		struct sctp_ecnehdr *ecne_hdr;
600 		struct sctp_cwrhdr *ecn_cwr_hdr;
601 		struct sctp_errhdr *err_hdr;
602 		struct sctp_addiphdr *addip_hdr;
603 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
604 		struct sctp_authhdr *auth_hdr;
605 		struct sctp_idatahdr *idata_hdr;
606 		struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
607 	} subh;
608 
609 	__u8 *chunk_end;
610 
611 	struct sctp_chunkhdr *chunk_hdr;
612 	struct sctphdr *sctp_hdr;
613 
614 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
615 	struct sctp_sndrcvinfo sinfo;
616 
617 	/* Which association does this belong to?  */
618 	struct sctp_association *asoc;
619 
620 	/* What endpoint received this chunk? */
621 	struct sctp_ep_common *rcvr;
622 
623 	/* We fill this in if we are calculating RTT. */
624 	unsigned long sent_at;
625 
626 	/* What is the origin IP address for this chunk?  */
627 	union sctp_addr source;
628 	/* Destination address for this chunk. */
629 	union sctp_addr dest;
630 
631 	/* For outbound message, track all fragments for SEND_FAILED. */
632 	struct sctp_datamsg *msg;
633 
634 	/* For an inbound chunk, this tells us where it came from.
635 	 * For an outbound chunk, it tells us where we'd like it to
636 	 * go.	It is NULL if we have no preference.
637 	 */
638 	struct sctp_transport *transport;
639 
640 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
641 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
642 	 * spec violates the principle premis that all chunks are processed
643 	 * in order.
644 	 */
645 	struct sk_buff *auth_chunk;
646 
647 #define SCTP_CAN_FRTX 0x0
648 #define SCTP_NEED_FRTX 0x1
649 #define SCTP_DONT_FRTX 0x2
650 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
651 		has_tsn:1,		/* Does this chunk have a TSN yet? */
652 		has_ssn:1,		/* Does this chunk have a SSN yet? */
653 #define has_mid has_ssn
654 		singleton:1,		/* Only chunk in the packet? */
655 		end_of_packet:1,	/* Last chunk in the packet? */
656 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
657 		pdiscard:1,		/* Discard the whole packet now? */
658 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
659 		data_accepted:1,	/* At least 1 chunk accepted */
660 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
661 		has_asconf:1,		/* IN: have seen an asconf before */
662 		tsn_missing_report:2,	/* Data chunk missing counter. */
663 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
664 };
665 
666 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
667 void sctp_chunk_hold(struct sctp_chunk *);
668 void sctp_chunk_put(struct sctp_chunk *);
669 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
670 			  struct iov_iter *from);
671 void sctp_chunk_free(struct sctp_chunk *);
672 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
673 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
674 				 const struct sctp_association *,
675 				 struct sock *, gfp_t gfp);
676 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
677 		     union sctp_addr *);
678 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
679 
680 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
681 {
682 	return ntohs(ch->subh.data_hdr->stream);
683 }
684 
685 enum {
686 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
687 	SCTP_ADDR_SRC,		/* address can be used as source */
688 	SCTP_ADDR_DEL,		/* address about to be deleted */
689 };
690 
691 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
692 struct sctp_sockaddr_entry {
693 	struct list_head list;
694 	struct rcu_head	rcu;
695 	union sctp_addr a;
696 	__u8 state;
697 	__u8 valid;
698 };
699 
700 #define SCTP_ADDRESS_TICK_DELAY	500
701 
702 /* This structure holds lists of chunks as we are assembling for
703  * transmission.
704  */
705 struct sctp_packet {
706 	/* These are the SCTP header values (host order) for the packet. */
707 	__u16 source_port;
708 	__u16 destination_port;
709 	__u32 vtag;
710 
711 	/* This contains the payload chunks.  */
712 	struct list_head chunk_list;
713 
714 	/* This is the overhead of the sctp and ip headers. */
715 	size_t overhead;
716 	/* This is the total size of all chunks INCLUDING padding.  */
717 	size_t size;
718 	/* This is the maximum size this packet may have */
719 	size_t max_size;
720 
721 	/* The packet is destined for this transport address.
722 	 * The function we finally use to pass down to the next lower
723 	 * layer lives in the transport structure.
724 	 */
725 	struct sctp_transport *transport;
726 
727 	/* pointer to the auth chunk for this packet */
728 	struct sctp_chunk *auth;
729 
730 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
731 	    has_sack:1,		/* This packet contains a SACK chunk. */
732 	    has_auth:1,		/* This packet contains an AUTH chunk */
733 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
734 	    ipfragok:1;		/* So let ip fragment this packet */
735 };
736 
737 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
738 		      __u16 sport, __u16 dport);
739 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
740 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
741 					  struct sctp_chunk *chunk,
742 					  int one_packet, gfp_t gfp);
743 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
744 					struct sctp_chunk *chunk);
745 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
746 void sctp_packet_free(struct sctp_packet *);
747 
748 static inline int sctp_packet_empty(struct sctp_packet *packet)
749 {
750 	return packet->size == packet->overhead;
751 }
752 
753 /* This represents a remote transport address.
754  * For local transport addresses, we just use union sctp_addr.
755  *
756  * RFC2960 Section 1.4 Key Terms
757  *
758  *   o	Transport address:  A Transport Address is traditionally defined
759  *	by Network Layer address, Transport Layer protocol and Transport
760  *	Layer port number.  In the case of SCTP running over IP, a
761  *	transport address is defined by the combination of an IP address
762  *	and an SCTP port number (where SCTP is the Transport protocol).
763  *
764  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
765  *
766  *   o	The sender keeps a separate congestion control parameter set for
767  *	each of the destination addresses it can send to (not each
768  *	source-destination pair but for each destination).  The parameters
769  *	should decay if the address is not used for a long enough time
770  *	period.
771  *
772  */
773 struct sctp_transport {
774 	/* A list of transports. */
775 	struct list_head transports;
776 	struct rhlist_head node;
777 
778 	/* Reference counting. */
779 	refcount_t refcnt;
780 		/* RTO-Pending : A flag used to track if one of the DATA
781 		 *		chunks sent to this address is currently being
782 		 *		used to compute a RTT. If this flag is 0,
783 		 *		the next DATA chunk sent to this destination
784 		 *		should be used to compute a RTT and this flag
785 		 *		should be set. Every time the RTT
786 		 *		calculation completes (i.e. the DATA chunk
787 		 *		is SACK'd) clear this flag.
788 		 */
789 	__u32	rto_pending:1,
790 
791 		/*
792 		 * hb_sent : a flag that signals that we have a pending
793 		 * heartbeat.
794 		 */
795 		hb_sent:1,
796 
797 		/* Is the Path MTU update pending on this tranport */
798 		pmtu_pending:1,
799 
800 		dst_pending_confirm:1,	/* need to confirm neighbour */
801 
802 		/* Has this transport moved the ctsn since we last sacked */
803 		sack_generation:1;
804 	u32 dst_cookie;
805 
806 	struct flowi fl;
807 
808 	/* This is the peer's IP address and port. */
809 	union sctp_addr ipaddr;
810 
811 	/* These are the functions we call to handle LLP stuff.	 */
812 	struct sctp_af *af_specific;
813 
814 	/* Which association do we belong to?  */
815 	struct sctp_association *asoc;
816 
817 	/* RFC2960
818 	 *
819 	 * 12.3 Per Transport Address Data
820 	 *
821 	 * For each destination transport address in the peer's
822 	 * address list derived from the INIT or INIT ACK chunk, a
823 	 * number of data elements needs to be maintained including:
824 	 */
825 	/* RTO	       : The current retransmission timeout value.  */
826 	unsigned long rto;
827 
828 	__u32 rtt;		/* This is the most recent RTT.	 */
829 
830 	/* RTTVAR      : The current RTT variation.  */
831 	__u32 rttvar;
832 
833 	/* SRTT	       : The current smoothed round trip time.	*/
834 	__u32 srtt;
835 
836 	/*
837 	 * These are the congestion stats.
838 	 */
839 	/* cwnd	       : The current congestion window.	 */
840 	__u32 cwnd;		  /* This is the actual cwnd.  */
841 
842 	/* ssthresh    : The current slow start threshold value.  */
843 	__u32 ssthresh;
844 
845 	/* partial     : The tracking method for increase of cwnd when in
846 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
847 	 */
848 	__u32 partial_bytes_acked;
849 
850 	/* Data that has been sent, but not acknowledged. */
851 	__u32 flight_size;
852 
853 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
854 
855 	/* Destination */
856 	struct dst_entry *dst;
857 	/* Source address. */
858 	union sctp_addr saddr;
859 
860 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
861 	 * the destination address every heartbeat interval.
862 	 */
863 	unsigned long hbinterval;
864 
865 	/* SACK delay timeout */
866 	unsigned long sackdelay;
867 	__u32 sackfreq;
868 
869 	atomic_t mtu_info;
870 
871 	/* When was the last time that we heard from this transport? We use
872 	 * this to pick new active and retran paths.
873 	 */
874 	ktime_t last_time_heard;
875 
876 	/* When was the last time that we sent a chunk using this
877 	 * transport? We use this to check for idle transports
878 	 */
879 	unsigned long last_time_sent;
880 
881 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
882 	 * indication based on ECNE chunk.
883 	 */
884 	unsigned long last_time_ecne_reduced;
885 
886 	/* This is the max_retrans value for the transport and will
887 	 * be initialized from the assocs value.  This can be changed
888 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
889 	 */
890 	__u16 pathmaxrxt;
891 
892 	__u32 flowlabel;
893 	__u8  dscp;
894 
895 	/* This is the partially failed retrans value for the transport
896 	 * and will be initialized from the assocs value.  This can be changed
897 	 * using the SCTP_PEER_ADDR_THLDS socket option
898 	 */
899 	int pf_retrans;
900 	/* PMTU	      : The current known path MTU.  */
901 	__u32 pathmtu;
902 
903 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
904 	__u32 param_flags;
905 
906 	/* The number of times INIT has been sent on this transport. */
907 	int init_sent_count;
908 
909 	/* state       : The current state of this destination,
910 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
911 	 */
912 	int state;
913 
914 	/* These are the error stats for this destination.  */
915 
916 	/* Error count : The current error count for this destination.	*/
917 	unsigned short error_count;
918 
919 	/* Per	       : A timer used by each destination.
920 	 * Destination :
921 	 * Timer       :
922 	 *
923 	 * [Everywhere else in the text this is called T3-rtx. -ed]
924 	 */
925 	struct timer_list T3_rtx_timer;
926 
927 	/* Heartbeat timer is per destination. */
928 	struct timer_list hb_timer;
929 
930 	/* Timer to handle ICMP proto unreachable envets */
931 	struct timer_list proto_unreach_timer;
932 
933 	/* Timer to handler reconf chunk rtx */
934 	struct timer_list reconf_timer;
935 
936 	/* Since we're using per-destination retransmission timers
937 	 * (see above), we're also using per-destination "transmitted"
938 	 * queues.  This probably ought to be a private struct
939 	 * accessible only within the outqueue, but it's not, yet.
940 	 */
941 	struct list_head transmitted;
942 
943 	/* We build bundle-able packets for this transport here.  */
944 	struct sctp_packet packet;
945 
946 	/* This is the list of transports that have chunks to send.  */
947 	struct list_head send_ready;
948 
949 	/* State information saved for SFR_CACC algorithm. The key
950 	 * idea in SFR_CACC is to maintain state at the sender on a
951 	 * per-destination basis when a changeover happens.
952 	 *	char changeover_active;
953 	 *	char cycling_changeover;
954 	 *	__u32 next_tsn_at_change;
955 	 *	char cacc_saw_newack;
956 	 */
957 	struct {
958 		/* An unsigned integer, which stores the next TSN to be
959 		 * used by the sender, at the moment of changeover.
960 		 */
961 		__u32 next_tsn_at_change;
962 
963 		/* A flag which indicates the occurrence of a changeover */
964 		char changeover_active;
965 
966 		/* A flag which indicates whether the change of primary is
967 		 * the first switch to this destination address during an
968 		 * active switch.
969 		 */
970 		char cycling_changeover;
971 
972 		/* A temporary flag, which is used during the processing of
973 		 * a SACK to estimate the causative TSN(s)'s group.
974 		 */
975 		char cacc_saw_newack;
976 	} cacc;
977 
978 	/* 64-bit random number sent with heartbeat. */
979 	__u64 hb_nonce;
980 
981 	struct rcu_head rcu;
982 };
983 
984 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
985 					  gfp_t);
986 void sctp_transport_set_owner(struct sctp_transport *,
987 			      struct sctp_association *);
988 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
989 			  struct sctp_sock *);
990 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
991 void sctp_transport_free(struct sctp_transport *);
992 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
993 void sctp_transport_reset_hb_timer(struct sctp_transport *);
994 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
995 int sctp_transport_hold(struct sctp_transport *);
996 void sctp_transport_put(struct sctp_transport *);
997 void sctp_transport_update_rto(struct sctp_transport *, __u32);
998 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
999 void sctp_transport_lower_cwnd(struct sctp_transport *t,
1000 			       enum sctp_lower_cwnd reason);
1001 void sctp_transport_burst_limited(struct sctp_transport *);
1002 void sctp_transport_burst_reset(struct sctp_transport *);
1003 unsigned long sctp_transport_timeout(struct sctp_transport *);
1004 void sctp_transport_reset(struct sctp_transport *t);
1005 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1006 void sctp_transport_immediate_rtx(struct sctp_transport *);
1007 void sctp_transport_dst_release(struct sctp_transport *t);
1008 void sctp_transport_dst_confirm(struct sctp_transport *t);
1009 
1010 
1011 /* This is the structure we use to queue packets as they come into
1012  * SCTP.  We write packets to it and read chunks from it.
1013  */
1014 struct sctp_inq {
1015 	/* This is actually a queue of sctp_chunk each
1016 	 * containing a partially decoded packet.
1017 	 */
1018 	struct list_head in_chunk_list;
1019 	/* This is the packet which is currently off the in queue and is
1020 	 * being worked on through the inbound chunk processing.
1021 	 */
1022 	struct sctp_chunk *in_progress;
1023 
1024 	/* This is the delayed task to finish delivering inbound
1025 	 * messages.
1026 	 */
1027 	struct work_struct immediate;
1028 };
1029 
1030 void sctp_inq_init(struct sctp_inq *);
1031 void sctp_inq_free(struct sctp_inq *);
1032 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1033 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1034 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1035 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1036 
1037 /* This is the structure we use to hold outbound chunks.  You push
1038  * chunks in and they automatically pop out the other end as bundled
1039  * packets (it calls (*output_handler)()).
1040  *
1041  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1042  * and 8.2 of the v13 draft.
1043  *
1044  * It handles retransmissions.	The connection to the timeout portion
1045  * of the state machine is through sctp_..._timeout() and timeout_handler.
1046  *
1047  * If you feed it SACKs, it will eat them.
1048  *
1049  * If you give it big chunks, it will fragment them.
1050  *
1051  * It assigns TSN's to data chunks.  This happens at the last possible
1052  * instant before transmission.
1053  *
1054  * When free()'d, it empties itself out via output_handler().
1055  */
1056 struct sctp_outq {
1057 	struct sctp_association *asoc;
1058 
1059 	/* Data pending that has never been transmitted.  */
1060 	struct list_head out_chunk_list;
1061 
1062 	/* Stream scheduler being used */
1063 	struct sctp_sched_ops *sched;
1064 
1065 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1066 
1067 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1068 	unsigned int error;
1069 
1070 	/* These are control chunks we want to send.  */
1071 	struct list_head control_chunk_list;
1072 
1073 	/* These are chunks that have been sacked but are above the
1074 	 * CTSN, or cumulative tsn ack point.
1075 	 */
1076 	struct list_head sacked;
1077 
1078 	/* Put chunks on this list to schedule them for
1079 	 * retransmission.
1080 	 */
1081 	struct list_head retransmit;
1082 
1083 	/* Put chunks on this list to save them for FWD TSN processing as
1084 	 * they were abandoned.
1085 	 */
1086 	struct list_head abandoned;
1087 
1088 	/* How many unackd bytes do we have in-flight?	*/
1089 	__u32 outstanding_bytes;
1090 
1091 	/* Are we doing fast-rtx on this queue */
1092 	char fast_rtx;
1093 
1094 	/* Corked? */
1095 	char cork;
1096 };
1097 
1098 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1099 void sctp_outq_teardown(struct sctp_outq *);
1100 void sctp_outq_free(struct sctp_outq*);
1101 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1102 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1103 int sctp_outq_is_empty(const struct sctp_outq *);
1104 void sctp_outq_restart(struct sctp_outq *);
1105 
1106 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1107 		     enum sctp_retransmit_reason reason);
1108 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1109 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1110 void sctp_prsctp_prune(struct sctp_association *asoc,
1111 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1112 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1113 /* Uncork and flush an outqueue.  */
1114 static inline void sctp_outq_cork(struct sctp_outq *q)
1115 {
1116 	q->cork = 1;
1117 }
1118 
1119 /* SCTP skb control block.
1120  * sctp_input_cb is currently used on rx and sock rx queue
1121  */
1122 struct sctp_input_cb {
1123 	union {
1124 		struct inet_skb_parm	h4;
1125 #if IS_ENABLED(CONFIG_IPV6)
1126 		struct inet6_skb_parm	h6;
1127 #endif
1128 	} header;
1129 	struct sctp_chunk *chunk;
1130 	struct sctp_af *af;
1131 };
1132 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1133 
1134 struct sctp_output_cb {
1135 	struct sk_buff *last;
1136 };
1137 #define SCTP_OUTPUT_CB(__skb)	((struct sctp_output_cb *)&((__skb)->cb[0]))
1138 
1139 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1140 {
1141 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1142 
1143 	return chunk->head_skb ? : skb;
1144 }
1145 
1146 /* These bind address data fields common between endpoints and associations */
1147 struct sctp_bind_addr {
1148 
1149 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1150 	 *
1151 	 * SCTP Port:	The local SCTP port number the endpoint is
1152 	 *		bound to.
1153 	 */
1154 	__u16 port;
1155 
1156 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1157 	 *
1158 	 * Address List: The list of IP addresses that this instance
1159 	 *	has bound.  This information is passed to one's
1160 	 *	peer(s) in INIT and INIT ACK chunks.
1161 	 */
1162 	struct list_head address_list;
1163 };
1164 
1165 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1166 void sctp_bind_addr_free(struct sctp_bind_addr *);
1167 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1168 			const struct sctp_bind_addr *src,
1169 			enum sctp_scope scope, gfp_t gfp,
1170 			int flags);
1171 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1172 			const struct sctp_bind_addr *src,
1173 			gfp_t gfp);
1174 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1175 		       int new_size, __u8 addr_state, gfp_t gfp);
1176 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1177 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1178 			 struct sctp_sock *);
1179 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1180 			 struct sctp_sock *, struct sctp_sock *);
1181 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1182 			 const union sctp_addr *addr);
1183 int sctp_bind_addrs_check(struct sctp_sock *sp,
1184 			  struct sctp_sock *sp2, int cnt2);
1185 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1186 					const union sctp_addr	*addrs,
1187 					int			addrcnt,
1188 					struct sctp_sock	*opt);
1189 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1190 					 int *addrs_len,
1191 					 gfp_t gfp);
1192 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1193 			   __u16 port, gfp_t gfp);
1194 
1195 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1196 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1197 		  const enum sctp_scope scope);
1198 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1199 int sctp_is_ep_boundall(struct sock *sk);
1200 
1201 
1202 /* What type of endpoint?  */
1203 enum sctp_endpoint_type {
1204 	SCTP_EP_TYPE_SOCKET,
1205 	SCTP_EP_TYPE_ASSOCIATION,
1206 };
1207 
1208 /*
1209  * A common base class to bridge the implmentation view of a
1210  * socket (usually listening) endpoint versus an association's
1211  * local endpoint.
1212  * This common structure is useful for several purposes:
1213  *   1) Common interface for lookup routines.
1214  *	a) Subfunctions work for either endpoint or association
1215  *	b) Single interface to lookup allows hiding the lookup lock rather
1216  *	   than acquiring it externally.
1217  *   2) Common interface for the inbound chunk handling/state machine.
1218  *   3) Common object handling routines for reference counting, etc.
1219  *   4) Disentangle association lookup from endpoint lookup, where we
1220  *	do not have to find our endpoint to find our association.
1221  *
1222  */
1223 
1224 struct sctp_ep_common {
1225 	/* Fields to help us manage our entries in the hash tables. */
1226 	struct hlist_node node;
1227 	int hashent;
1228 
1229 	/* Runtime type information.  What kind of endpoint is this? */
1230 	enum sctp_endpoint_type type;
1231 
1232 	/* Some fields to help us manage this object.
1233 	 *   refcnt   - Reference count access to this object.
1234 	 *   dead     - Do not attempt to use this object.
1235 	 */
1236 	refcount_t    refcnt;
1237 	bool	    dead;
1238 
1239 	/* What socket does this endpoint belong to?  */
1240 	struct sock *sk;
1241 
1242 	/* This is where we receive inbound chunks.  */
1243 	struct sctp_inq	  inqueue;
1244 
1245 	/* This substructure includes the defining parameters of the
1246 	 * endpoint:
1247 	 * bind_addr.port is our shared port number.
1248 	 * bind_addr.address_list is our set of local IP addresses.
1249 	 */
1250 	struct sctp_bind_addr bind_addr;
1251 };
1252 
1253 
1254 /* RFC Section 1.4 Key Terms
1255  *
1256  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1257  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1258  *   combination of a set of eligible destination transport addresses to
1259  *   which SCTP packets can be sent and a set of eligible source
1260  *   transport addresses from which SCTP packets can be received.
1261  *   All transport addresses used by an SCTP endpoint must use the
1262  *   same port number, but can use multiple IP addresses. A transport
1263  *   address used by an SCTP endpoint must not be used by another
1264  *   SCTP endpoint. In other words, a transport address is unique
1265  *   to an SCTP endpoint.
1266  *
1267  * From an implementation perspective, each socket has one of these.
1268  * A TCP-style socket will have exactly one association on one of
1269  * these.  An UDP-style socket will have multiple associations hanging
1270  * off one of these.
1271  */
1272 
1273 struct sctp_endpoint {
1274 	/* Common substructure for endpoint and association. */
1275 	struct sctp_ep_common base;
1276 
1277 	/* Associations: A list of current associations and mappings
1278 	 *	      to the data consumers for each association. This
1279 	 *	      may be in the form of a hash table or other
1280 	 *	      implementation dependent structure. The data
1281 	 *	      consumers may be process identification
1282 	 *	      information such as file descriptors, named pipe
1283 	 *	      pointer, or table pointers dependent on how SCTP
1284 	 *	      is implemented.
1285 	 */
1286 	/* This is really a list of struct sctp_association entries. */
1287 	struct list_head asocs;
1288 
1289 	/* Secret Key: A secret key used by this endpoint to compute
1290 	 *	      the MAC.	This SHOULD be a cryptographic quality
1291 	 *	      random number with a sufficient length.
1292 	 *	      Discussion in [RFC1750] can be helpful in
1293 	 *	      selection of the key.
1294 	 */
1295 	__u8 secret_key[SCTP_SECRET_SIZE];
1296 
1297  	/* digest:  This is a digest of the sctp cookie.  This field is
1298  	 * 	    only used on the receive path when we try to validate
1299  	 * 	    that the cookie has not been tampered with.  We put
1300  	 * 	    this here so we pre-allocate this once and can re-use
1301  	 * 	    on every receive.
1302  	 */
1303  	__u8 *digest;
1304 
1305 	/* sendbuf acct. policy.	*/
1306 	__u32 sndbuf_policy;
1307 
1308 	/* rcvbuf acct. policy.	*/
1309 	__u32 rcvbuf_policy;
1310 
1311 	/* SCTP AUTH: array of the HMACs that will be allocated
1312 	 * we need this per association so that we don't serialize
1313 	 */
1314 	struct crypto_shash **auth_hmacs;
1315 
1316 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1317 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1318 
1319 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1320 	struct sctp_chunks_param *auth_chunk_list;
1321 
1322 	/* SCTP-AUTH: endpoint shared keys */
1323 	struct list_head endpoint_shared_keys;
1324 	__u16 active_key_id;
1325 	__u8  ecn_enable:1,
1326 	      auth_enable:1,
1327 	      intl_enable:1,
1328 	      prsctp_enable:1,
1329 	      asconf_enable:1,
1330 	      reconf_enable:1;
1331 
1332 	__u8  strreset_enable;
1333 
1334 	/* Security identifiers from incoming (INIT). These are set by
1335 	 * security_sctp_assoc_request(). These will only be used by
1336 	 * SCTP TCP type sockets and peeled off connections as they
1337 	 * cause a new socket to be generated. security_sctp_sk_clone()
1338 	 * will then plug these into the new socket.
1339 	 */
1340 
1341 	u32 secid;
1342 	u32 peer_secid;
1343 };
1344 
1345 /* Recover the outter endpoint structure. */
1346 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1347 {
1348 	struct sctp_endpoint *ep;
1349 
1350 	ep = container_of(base, struct sctp_endpoint, base);
1351 	return ep;
1352 }
1353 
1354 /* These are function signatures for manipulating endpoints.  */
1355 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1356 void sctp_endpoint_free(struct sctp_endpoint *);
1357 void sctp_endpoint_put(struct sctp_endpoint *);
1358 void sctp_endpoint_hold(struct sctp_endpoint *);
1359 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1360 struct sctp_association *sctp_endpoint_lookup_assoc(
1361 	const struct sctp_endpoint *ep,
1362 	const union sctp_addr *paddr,
1363 	struct sctp_transport **);
1364 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1365 				 const union sctp_addr *paddr);
1366 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1367 					struct net *, const union sctp_addr *);
1368 bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1369 			  const union sctp_addr *paddr);
1370 
1371 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1372 		     const struct sctp_association *asoc,
1373 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1374 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1375 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1376 		      const union sctp_addr *peer,
1377 		      struct sctp_init_chunk *init, gfp_t gfp);
1378 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1379 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1380 
1381 struct sctp_inithdr_host {
1382 	__u32 init_tag;
1383 	__u32 a_rwnd;
1384 	__u16 num_outbound_streams;
1385 	__u16 num_inbound_streams;
1386 	__u32 initial_tsn;
1387 };
1388 
1389 struct sctp_stream_priorities {
1390 	/* List of priorities scheduled */
1391 	struct list_head prio_sched;
1392 	/* List of streams scheduled */
1393 	struct list_head active;
1394 	/* The next stream stream in line */
1395 	struct sctp_stream_out_ext *next;
1396 	__u16 prio;
1397 };
1398 
1399 struct sctp_stream_out_ext {
1400 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1401 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1402 	struct list_head outq; /* chunks enqueued by this stream */
1403 	union {
1404 		struct {
1405 			/* Scheduled streams list */
1406 			struct list_head prio_list;
1407 			struct sctp_stream_priorities *prio_head;
1408 		};
1409 		/* Fields used by RR scheduler */
1410 		struct {
1411 			struct list_head rr_list;
1412 		};
1413 	};
1414 };
1415 
1416 struct sctp_stream_out {
1417 	union {
1418 		__u32 mid;
1419 		__u16 ssn;
1420 	};
1421 	__u32 mid_uo;
1422 	struct sctp_stream_out_ext *ext;
1423 	__u8 state;
1424 };
1425 
1426 struct sctp_stream_in {
1427 	union {
1428 		__u32 mid;
1429 		__u16 ssn;
1430 	};
1431 	__u32 mid_uo;
1432 	__u32 fsn;
1433 	__u32 fsn_uo;
1434 	char pd_mode;
1435 	char pd_mode_uo;
1436 };
1437 
1438 struct sctp_stream {
1439 	GENRADIX(struct sctp_stream_out) out;
1440 	GENRADIX(struct sctp_stream_in)	in;
1441 
1442 	__u16 outcnt;
1443 	__u16 incnt;
1444 	/* Current stream being sent, if any */
1445 	struct sctp_stream_out *out_curr;
1446 	union {
1447 		/* Fields used by priority scheduler */
1448 		struct {
1449 			/* List of priorities scheduled */
1450 			struct list_head prio_list;
1451 		};
1452 		/* Fields used by RR scheduler */
1453 		struct {
1454 			/* List of streams scheduled */
1455 			struct list_head rr_list;
1456 			/* The next stream stream in line */
1457 			struct sctp_stream_out_ext *rr_next;
1458 		};
1459 	};
1460 	struct sctp_stream_interleave *si;
1461 };
1462 
1463 static inline struct sctp_stream_out *sctp_stream_out(
1464 	struct sctp_stream *stream,
1465 	__u16 sid)
1466 {
1467 	return genradix_ptr(&stream->out, sid);
1468 }
1469 
1470 static inline struct sctp_stream_in *sctp_stream_in(
1471 	struct sctp_stream *stream,
1472 	__u16 sid)
1473 {
1474 	return genradix_ptr(&stream->in, sid);
1475 }
1476 
1477 #define SCTP_SO(s, i) sctp_stream_out((s), (i))
1478 #define SCTP_SI(s, i) sctp_stream_in((s), (i))
1479 
1480 #define SCTP_STREAM_CLOSED		0x00
1481 #define SCTP_STREAM_OPEN		0x01
1482 
1483 static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1484 {
1485 	return stream->si->data_chunk_len;
1486 }
1487 
1488 static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1489 {
1490 	return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1491 }
1492 
1493 static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1494 {
1495 	return stream->si->ftsn_chunk_len;
1496 }
1497 
1498 static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1499 {
1500 	return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1501 }
1502 
1503 /* SCTP_GET_ASSOC_STATS counters */
1504 struct sctp_priv_assoc_stats {
1505 	/* Maximum observed rto in the association during subsequent
1506 	 * observations. Value is set to 0 if no RTO measurement took place
1507 	 * The transport where the max_rto was observed is returned in
1508 	 * obs_rto_ipaddr
1509 	 */
1510 	struct sockaddr_storage obs_rto_ipaddr;
1511 	__u64 max_obs_rto;
1512 	/* Total In and Out SACKs received and sent */
1513 	__u64 isacks;
1514 	__u64 osacks;
1515 	/* Total In and Out packets received and sent */
1516 	__u64 opackets;
1517 	__u64 ipackets;
1518 	/* Total retransmitted chunks */
1519 	__u64 rtxchunks;
1520 	/* TSN received > next expected */
1521 	__u64 outofseqtsns;
1522 	/* Duplicate Chunks received */
1523 	__u64 idupchunks;
1524 	/* Gap Ack Blocks received */
1525 	__u64 gapcnt;
1526 	/* Unordered data chunks sent and received */
1527 	__u64 ouodchunks;
1528 	__u64 iuodchunks;
1529 	/* Ordered data chunks sent and received */
1530 	__u64 oodchunks;
1531 	__u64 iodchunks;
1532 	/* Control chunks sent and received */
1533 	__u64 octrlchunks;
1534 	__u64 ictrlchunks;
1535 };
1536 
1537 /* RFC2960
1538  *
1539  * 12. Recommended Transmission Control Block (TCB) Parameters
1540  *
1541  * This section details a recommended set of parameters that should
1542  * be contained within the TCB for an implementation. This section is
1543  * for illustrative purposes and should not be deemed as requirements
1544  * on an implementation or as an exhaustive list of all parameters
1545  * inside an SCTP TCB. Each implementation may need its own additional
1546  * parameters for optimization.
1547  */
1548 
1549 
1550 /* Here we have information about each individual association. */
1551 struct sctp_association {
1552 
1553 	/* A base structure common to endpoint and association.
1554 	 * In this context, it represents the associations's view
1555 	 * of the local endpoint of the association.
1556 	 */
1557 	struct sctp_ep_common base;
1558 
1559 	/* Associations on the same socket. */
1560 	struct list_head asocs;
1561 
1562 	/* association id. */
1563 	sctp_assoc_t assoc_id;
1564 
1565 	/* This is our parent endpoint.	 */
1566 	struct sctp_endpoint *ep;
1567 
1568 	/* These are those association elements needed in the cookie.  */
1569 	struct sctp_cookie c;
1570 
1571 	/* This is all information about our peer.  */
1572 	struct {
1573 		/* transport_addr_list
1574 		 *
1575 		 * Peer	       : A list of SCTP transport addresses that the
1576 		 * Transport   : peer is bound to. This information is derived
1577 		 * Address     : from the INIT or INIT ACK and is used to
1578 		 * List	       : associate an inbound packet with a given
1579 		 *	       : association. Normally this information is
1580 		 *	       : hashed or keyed for quick lookup and access
1581 		 *	       : of the TCB.
1582 		 *	       : The list is also initialized with the list
1583 		 *	       : of addresses passed with the sctp_connectx()
1584 		 *	       : call.
1585 		 *
1586 		 * It is a list of SCTP_transport's.
1587 		 */
1588 		struct list_head transport_addr_list;
1589 
1590 		/* rwnd
1591 		 *
1592 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1593 		 */
1594 		__u32 rwnd;
1595 
1596 		/* transport_count
1597 		 *
1598 		 * Peer        : A count of the number of peer addresses
1599 		 * Transport   : in the Peer Transport Address List.
1600 		 * Address     :
1601 		 * Count       :
1602 		 */
1603 		__u16 transport_count;
1604 
1605 		/* port
1606 		 *   The transport layer port number.
1607 		 */
1608 		__u16 port;
1609 
1610 		/* primary_path
1611 		 *
1612 		 * Primary     : This is the current primary destination
1613 		 * Path	       : transport address of the peer endpoint.  It
1614 		 *	       : may also specify a source transport address
1615 		 *	       : on this endpoint.
1616 		 *
1617 		 * All of these paths live on transport_addr_list.
1618 		 *
1619 		 * At the bakeoffs, we discovered that the intent of
1620 		 * primaryPath is that it only changes when the ULP
1621 		 * asks to have it changed.  We add the activePath to
1622 		 * designate the connection we are currently using to
1623 		 * transmit new data and most control chunks.
1624 		 */
1625 		struct sctp_transport *primary_path;
1626 
1627 		/* Cache the primary path address here, when we
1628 		 * need a an address for msg_name.
1629 		 */
1630 		union sctp_addr primary_addr;
1631 
1632 		/* active_path
1633 		 *   The path that we are currently using to
1634 		 *   transmit new data and most control chunks.
1635 		 */
1636 		struct sctp_transport *active_path;
1637 
1638 		/* retran_path
1639 		 *
1640 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1641 		 * ...
1642 		 * Furthermore, when its peer is multi-homed, an
1643 		 * endpoint SHOULD try to retransmit a chunk to an
1644 		 * active destination transport address that is
1645 		 * different from the last destination address to
1646 		 * which the DATA chunk was sent.
1647 		 */
1648 		struct sctp_transport *retran_path;
1649 
1650 		/* Pointer to last transport I have sent on.  */
1651 		struct sctp_transport *last_sent_to;
1652 
1653 		/* This is the last transport I have received DATA on.	*/
1654 		struct sctp_transport *last_data_from;
1655 
1656 		/*
1657 		 * Mapping  An array of bits or bytes indicating which out of
1658 		 * Array    order TSN's have been received (relative to the
1659 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1660 		 *	    order packets have been received, this array
1661 		 *	    will be set to all zero. This structure may be
1662 		 *	    in the form of a circular buffer or bit array.
1663 		 *
1664 		 * Last Rcvd   : This is the last TSN received in
1665 		 * TSN	       : sequence. This value is set initially by
1666 		 *	       : taking the peer's Initial TSN, received in
1667 		 *	       : the INIT or INIT ACK chunk, and subtracting
1668 		 *	       : one from it.
1669 		 *
1670 		 * Throughout most of the specification this is called the
1671 		 * "Cumulative TSN ACK Point".	In this case, we
1672 		 * ignore the advice in 12.2 in favour of the term
1673 		 * used in the bulk of the text.  This value is hidden
1674 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1675 		 */
1676 		struct sctp_tsnmap tsn_map;
1677 
1678 		/* This mask is used to disable sending the ASCONF chunk
1679 		 * with specified parameter to peer.
1680 		 */
1681 		__be16 addip_disabled_mask;
1682 
1683 		/* These are capabilities which our peer advertised.  */
1684 		__u16	ecn_capable:1,      /* Can peer do ECN? */
1685 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1686 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1687 			hostname_address:1, /* Peer understands DNS addresses? */
1688 			asconf_capable:1,   /* Does peer support ADDIP? */
1689 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1690 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1691 			intl_capable:1,     /* Can peer do INTERLEAVE */
1692 			auth_capable:1,     /* Is peer doing SCTP-AUTH? */
1693 			/* sack_needed:
1694 			 *   This flag indicates if the next received
1695 			 *   packet is to be responded to with a
1696 			 *   SACK. This is initialized to 0.  When a packet
1697 			 *   is received sack_cnt is incremented. If this value
1698 			 *   reaches 2 or more, a SACK is sent and the
1699 			 *   value is reset to 0. Note: This is used only
1700 			 *   when no DATA chunks are received out of
1701 			 *   order.  When DATA chunks are out of order,
1702 			 *   SACK's are not delayed (see Section 6).
1703 			 */
1704 			sack_needed:1,     /* Do we need to sack the peer? */
1705 			sack_generation:1,
1706 			zero_window_announced:1;
1707 
1708 		__u32	sack_cnt;
1709 
1710 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1711 
1712 		struct sctp_inithdr_host i;
1713 		void *cookie;
1714 		int cookie_len;
1715 
1716 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1717 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1718 		 * Initial TSN Value minus 1
1719 		 */
1720 		__u32 addip_serial;
1721 
1722 		/* SCTP-AUTH: We need to know pears random number, hmac list
1723 		 * and authenticated chunk list.  All that is part of the
1724 		 * cookie and these are just pointers to those locations
1725 		 */
1726 		struct sctp_random_param *peer_random;
1727 		struct sctp_chunks_param *peer_chunks;
1728 		struct sctp_hmac_algo_param *peer_hmacs;
1729 	} peer;
1730 
1731 	/* State       : A state variable indicating what state the
1732 	 *	       : association is in, i.e. COOKIE-WAIT,
1733 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1734 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1735 	 *
1736 	 *		Note: No "CLOSED" state is illustrated since if a
1737 	 *		association is "CLOSED" its TCB SHOULD be removed.
1738 	 *
1739 	 *		In this implementation we DO have a CLOSED
1740 	 *		state which is used during initiation and shutdown.
1741 	 *
1742 	 *		State takes values from SCTP_STATE_*.
1743 	 */
1744 	enum sctp_state state;
1745 
1746 	/* Overall     : The overall association error count.
1747 	 * Error Count : [Clear this any time I get something.]
1748 	 */
1749 	int overall_error_count;
1750 
1751 	/* The cookie life I award for any cookie.  */
1752 	ktime_t cookie_life;
1753 
1754 	/* These are the association's initial, max, and min RTO values.
1755 	 * These values will be initialized by system defaults, but can
1756 	 * be modified via the SCTP_RTOINFO socket option.
1757 	 */
1758 	unsigned long rto_initial;
1759 	unsigned long rto_max;
1760 	unsigned long rto_min;
1761 
1762 	/* Maximum number of new data packets that can be sent in a burst.  */
1763 	int max_burst;
1764 
1765 	/* This is the max_retrans value for the association.  This value will
1766 	 * be initialized initialized from system defaults, but can be
1767 	 * modified by the SCTP_ASSOCINFO socket option.
1768 	 */
1769 	int max_retrans;
1770 
1771 	/* This is the partially failed retrans value for the transport
1772 	 * and will be initialized from the assocs value.  This can be
1773 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1774 	 */
1775 	int pf_retrans;
1776 
1777 	/* Maximum number of times the endpoint will retransmit INIT  */
1778 	__u16 max_init_attempts;
1779 
1780 	/* How many times have we resent an INIT? */
1781 	__u16 init_retries;
1782 
1783 	/* The largest timeout or RTO value to use in attempting an INIT */
1784 	unsigned long max_init_timeo;
1785 
1786 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1787 	 * the destination address every heartbeat interval. This value
1788 	 * will be inherited by all new transports.
1789 	 */
1790 	unsigned long hbinterval;
1791 
1792 	/* This is the max_retrans value for new transports in the
1793 	 * association.
1794 	 */
1795 	__u16 pathmaxrxt;
1796 
1797 	__u32 flowlabel;
1798 	__u8  dscp;
1799 
1800 	/* Flag that path mtu update is pending */
1801 	__u8   pmtu_pending;
1802 
1803 	/* Association : The smallest PMTU discovered for all of the
1804 	 * PMTU	       : peer's transport addresses.
1805 	 */
1806 	__u32 pathmtu;
1807 
1808 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1809 	__u32 param_flags;
1810 
1811 	__u32 sackfreq;
1812 	/* SACK delay timeout */
1813 	unsigned long sackdelay;
1814 
1815 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1816 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1817 
1818 	/* Transport to which SHUTDOWN chunk was last sent.  */
1819 	struct sctp_transport *shutdown_last_sent_to;
1820 
1821 	/* Transport to which INIT chunk was last sent.  */
1822 	struct sctp_transport *init_last_sent_to;
1823 
1824 	/* How many times have we resent a SHUTDOWN */
1825 	int shutdown_retries;
1826 
1827 	/* Next TSN    : The next TSN number to be assigned to a new
1828 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1829 	 *	       : ACK chunk to the peer and incremented each
1830 	 *	       : time a DATA chunk is assigned a TSN
1831 	 *	       : (normally just prior to transmit or during
1832 	 *	       : fragmentation).
1833 	 */
1834 	__u32 next_tsn;
1835 
1836 	/*
1837 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1838 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1839 	 *	       : received in the INIT or INIT ACK chunk, and
1840 	 *	       : subtracting one from it.
1841 	 *
1842 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1843 	 */
1844 
1845 	__u32 ctsn_ack_point;
1846 
1847 	/* PR-SCTP Advanced.Peer.Ack.Point */
1848 	__u32 adv_peer_ack_point;
1849 
1850 	/* Highest TSN that is acknowledged by incoming SACKs. */
1851 	__u32 highest_sacked;
1852 
1853 	/* TSN marking the fast recovery exit point */
1854 	__u32 fast_recovery_exit;
1855 
1856 	/* Flag to track the current fast recovery state */
1857 	__u8 fast_recovery;
1858 
1859 	/* The number of unacknowledged data chunks.  Reported through
1860 	 * the SCTP_STATUS sockopt.
1861 	 */
1862 	__u16 unack_data;
1863 
1864 	/* The total number of data chunks that we've had to retransmit
1865 	 * as the result of a T3 timer expiration
1866 	 */
1867 	__u32 rtx_data_chunks;
1868 
1869 	/* This is the association's receive buffer space.  This value is used
1870 	 * to set a_rwnd field in an INIT or a SACK chunk.
1871 	 */
1872 	__u32 rwnd;
1873 
1874 	/* This is the last advertised value of rwnd over a SACK chunk. */
1875 	__u32 a_rwnd;
1876 
1877 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1878 	 * to slop over a maximum of the association's frag_point.
1879 	 */
1880 	__u32 rwnd_over;
1881 
1882 	/* Keeps treack of rwnd pressure.  This happens when we have
1883 	 * a window, but not recevie buffer (i.e small packets).  This one
1884 	 * is releases slowly (1 PMTU at a time ).
1885 	 */
1886 	__u32 rwnd_press;
1887 
1888 	/* This is the sndbuf size in use for the association.
1889 	 * This corresponds to the sndbuf size for the association,
1890 	 * as specified in the sk->sndbuf.
1891 	 */
1892 	int sndbuf_used;
1893 
1894 	/* This is the amount of memory that this association has allocated
1895 	 * in the receive path at any given time.
1896 	 */
1897 	atomic_t rmem_alloc;
1898 
1899 	/* This is the wait queue head for send requests waiting on
1900 	 * the association sndbuf space.
1901 	 */
1902 	wait_queue_head_t	wait;
1903 
1904 	/* The message size at which SCTP fragmentation will occur. */
1905 	__u32 frag_point;
1906 	__u32 user_frag;
1907 
1908 	/* Counter used to count INIT errors. */
1909 	int init_err_counter;
1910 
1911 	/* Count the number of INIT cycles (for doubling timeout). */
1912 	int init_cycle;
1913 
1914 	/* Default send parameters. */
1915 	__u16 default_stream;
1916 	__u16 default_flags;
1917 	__u32 default_ppid;
1918 	__u32 default_context;
1919 	__u32 default_timetolive;
1920 
1921 	/* Default receive parameters */
1922 	__u32 default_rcv_context;
1923 
1924 	/* Stream arrays */
1925 	struct sctp_stream stream;
1926 
1927 	/* All outbound chunks go through this structure.  */
1928 	struct sctp_outq outqueue;
1929 
1930 	/* A smart pipe that will handle reordering and fragmentation,
1931 	 * as well as handle passing events up to the ULP.
1932 	 */
1933 	struct sctp_ulpq ulpq;
1934 
1935 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1936 	__u32 last_ecne_tsn;
1937 
1938 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1939 	__u32 last_cwr_tsn;
1940 
1941 	/* How many duplicated TSNs have we seen?  */
1942 	int numduptsns;
1943 
1944 	/* These are to support
1945 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1946 	 *  and Enforcement of Flow and Message Limits"
1947 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1948 	 * or "ADDIP" for short.
1949 	 */
1950 
1951 
1952 
1953 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1954 	 *
1955 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1956 	 * unacknowledged at any one time.  If a sender, after sending
1957 	 * an ASCONF chunk, decides it needs to transfer another
1958 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1959 	 * returns from the previous ASCONF Chunk before sending a
1960 	 * subsequent ASCONF. Note this restriction binds each side,
1961 	 * so at any time two ASCONF may be in-transit on any given
1962 	 * association (one sent from each endpoint).
1963 	 *
1964 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1965 	 * not have an ASCONF in flight, this is NULL.]
1966 	 */
1967 	struct sctp_chunk *addip_last_asconf;
1968 
1969 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1970 	 *
1971 	 * This is needed to implement itmes E1 - E4 of the updated
1972 	 * spec.  Here is the justification:
1973 	 *
1974 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1975 	 * we now need the ability to cache multiple ACKs.  The section
1976 	 * describes in detail how they are cached and cleaned up.
1977 	 */
1978 	struct list_head asconf_ack_list;
1979 
1980 	/* These ASCONF chunks are waiting to be sent.
1981 	 *
1982 	 * These chunaks can't be pushed to outqueue until receiving
1983 	 * ASCONF_ACK for the previous ASCONF indicated by
1984 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1985 	 * is in flight at any time.
1986 	 *
1987 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1988 	 *
1989 	 * In defining the ASCONF Chunk transfer procedures, it is
1990 	 * essential that these transfers MUST NOT cause congestion
1991 	 * within the network.	To achieve this, we place these
1992 	 * restrictions on the transfer of ASCONF Chunks:
1993 	 *
1994 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1995 	 * unacknowledged at any one time.  If a sender, after sending
1996 	 * an ASCONF chunk, decides it needs to transfer another
1997 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1998 	 * returns from the previous ASCONF Chunk before sending a
1999 	 * subsequent ASCONF. Note this restriction binds each side,
2000 	 * so at any time two ASCONF may be in-transit on any given
2001 	 * association (one sent from each endpoint).
2002 	 *
2003 	 *
2004 	 * [I really think this is EXACTLY the sort of intelligence
2005 	 *  which already resides in sctp_outq.	 Please move this
2006 	 *  queue and its supporting logic down there.	--piggy]
2007 	 */
2008 	struct list_head addip_chunk_list;
2009 
2010 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2011 	 *
2012 	 * A2) A serial number should be assigned to the Chunk. The
2013 	 * serial number SHOULD be a monotonically increasing
2014 	 * number. The serial number SHOULD be initialized at
2015 	 * the start of the association to the same value as the
2016 	 * Initial TSN and every time a new ASCONF chunk is created
2017 	 * it is incremented by one after assigning the serial number
2018 	 * to the newly created chunk.
2019 	 *
2020 	 * ADDIP
2021 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
2022 	 *
2023 	 * Serial Number : 32 bits (unsigned integer)
2024 	 *
2025 	 * This value represents a Serial Number for the ASCONF
2026 	 * Chunk. The valid range of Serial Number is from 0 to
2027 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
2028 	 * after reaching 4294967295.
2029 	 */
2030 	__u32 addip_serial;
2031 	int src_out_of_asoc_ok;
2032 	union sctp_addr *asconf_addr_del_pending;
2033 	struct sctp_transport *new_transport;
2034 
2035 	/* SCTP AUTH: list of the endpoint shared keys.  These
2036 	 * keys are provided out of band by the user applicaton
2037 	 * and can't change during the lifetime of the association
2038 	 */
2039 	struct list_head endpoint_shared_keys;
2040 
2041 	/* SCTP AUTH:
2042 	 * The current generated assocaition shared key (secret)
2043 	 */
2044 	struct sctp_auth_bytes *asoc_shared_key;
2045 	struct sctp_shared_key *shkey;
2046 
2047 	/* SCTP AUTH: hmac id of the first peer requested algorithm
2048 	 * that we support.
2049 	 */
2050 	__u16 default_hmac_id;
2051 
2052 	__u16 active_key_id;
2053 
2054 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
2055 	     temp:1,		/* Is it a temporary association? */
2056 	     force_delay:1;
2057 
2058 	__u8 strreset_enable;
2059 	__u8 strreset_outstanding; /* request param count on the fly */
2060 
2061 	__u32 strreset_outseq; /* Update after receiving response */
2062 	__u32 strreset_inseq; /* Update after receiving request */
2063 	__u32 strreset_result[2]; /* save the results of last 2 responses */
2064 
2065 	struct sctp_chunk *strreset_chunk; /* save request chunk */
2066 
2067 	struct sctp_priv_assoc_stats stats;
2068 
2069 	int sent_cnt_removable;
2070 
2071 	__u16 subscribe;
2072 
2073 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2074 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2075 
2076 	struct rcu_head rcu;
2077 };
2078 
2079 
2080 /* An eyecatcher for determining if we are really looking at an
2081  * association data structure.
2082  */
2083 enum {
2084 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
2085 };
2086 
2087 /* Recover the outter association structure. */
2088 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2089 {
2090 	struct sctp_association *asoc;
2091 
2092 	asoc = container_of(base, struct sctp_association, base);
2093 	return asoc;
2094 }
2095 
2096 /* These are function signatures for manipulating associations.	 */
2097 
2098 
2099 struct sctp_association *
2100 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2101 		     enum sctp_scope scope, gfp_t gfp);
2102 void sctp_association_free(struct sctp_association *);
2103 void sctp_association_put(struct sctp_association *);
2104 void sctp_association_hold(struct sctp_association *);
2105 
2106 struct sctp_transport *sctp_assoc_choose_alter_transport(
2107 	struct sctp_association *, struct sctp_transport *);
2108 void sctp_assoc_update_retran_path(struct sctp_association *);
2109 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2110 					  const union sctp_addr *);
2111 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2112 			    const union sctp_addr *laddr);
2113 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2114 				     const union sctp_addr *address,
2115 				     const gfp_t gfp,
2116 				     const int peer_state);
2117 void sctp_assoc_del_peer(struct sctp_association *asoc,
2118 			 const union sctp_addr *addr);
2119 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2120 			 struct sctp_transport *peer);
2121 void sctp_assoc_control_transport(struct sctp_association *asoc,
2122 				  struct sctp_transport *transport,
2123 				  enum sctp_transport_cmd command,
2124 				  sctp_sn_error_t error);
2125 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2126 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2127 int sctp_assoc_update(struct sctp_association *old,
2128 		      struct sctp_association *new);
2129 
2130 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2131 
2132 void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2133 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2134 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2135 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2136 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2137 void sctp_assoc_set_primary(struct sctp_association *,
2138 			    struct sctp_transport *);
2139 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2140 				    struct sctp_transport *);
2141 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2142 				     enum sctp_scope scope, gfp_t gfp);
2143 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2144 					 struct sctp_cookie*,
2145 					 gfp_t gfp);
2146 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2147 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2148 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2149 					const struct sctp_association *asoc,
2150 					__be32 serial);
2151 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2152 
2153 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2154 			const union sctp_addr *ss2);
2155 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2156 
2157 /* A convenience structure to parse out SCTP specific CMSGs. */
2158 struct sctp_cmsgs {
2159 	struct sctp_initmsg *init;
2160 	struct sctp_sndrcvinfo *srinfo;
2161 	struct sctp_sndinfo *sinfo;
2162 	struct sctp_prinfo *prinfo;
2163 	struct sctp_authinfo *authinfo;
2164 	struct msghdr *addrs_msg;
2165 };
2166 
2167 /* Structure for tracking memory objects */
2168 struct sctp_dbg_objcnt_entry {
2169 	char *label;
2170 	atomic_t *counter;
2171 };
2172 
2173 #endif /* __sctp_structs_h__ */
2174