xref: /openbmc/linux/include/net/sctp/structs.h (revision 4ea0c32f)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * This SCTP implementation is free software;
10  * you can redistribute it and/or modify it under the terms of
11  * the GNU General Public License as published by
12  * the Free Software Foundation; either version 2, or (at your option)
13  * any later version.
14  *
15  * This SCTP implementation is distributed in the hope that it
16  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17  *		   ************************
18  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19  * See the GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with GNU CC; see the file COPYING.  If not, see
23  * <http://www.gnu.org/licenses/>.
24  *
25  * Please send any bug reports or fixes you make to the
26  * email addresses:
27  *    lksctp developers <linux-sctp@vger.kernel.org>
28  *
29  * Written or modified by:
30  *    Randall Stewart	    <randall@sctp.chicago.il.us>
31  *    Ken Morneau	    <kmorneau@cisco.com>
32  *    Qiaobing Xie	    <qxie1@email.mot.com>
33  *    La Monte H.P. Yarroll <piggy@acm.org>
34  *    Karl Knutson	    <karl@athena.chicago.il.us>
35  *    Jon Grimm		    <jgrimm@us.ibm.com>
36  *    Xingang Guo	    <xingang.guo@intel.com>
37  *    Hui Huang		    <hui.huang@nokia.com>
38  *    Sridhar Samudrala	    <sri@us.ibm.com>
39  *    Daisy Chang	    <daisyc@us.ibm.com>
40  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
41  *    Ardelle Fan	    <ardelle.fan@intel.com>
42  *    Ryan Layer	    <rmlayer@us.ibm.com>
43  *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
44  *    Kevin Gao             <kevin.gao@intel.com>
45  */
46 
47 #ifndef __sctp_structs_h__
48 #define __sctp_structs_h__
49 
50 #include <linux/ktime.h>
51 #include <linux/rhashtable.h>
52 #include <linux/socket.h>	/* linux/in.h needs this!!    */
53 #include <linux/in.h>		/* We get struct sockaddr_in. */
54 #include <linux/in6.h>		/* We get struct in6_addr     */
55 #include <linux/ipv6.h>
56 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
57 #include <linux/atomic.h>		/* This gets us atomic counters.  */
58 #include <linux/skbuff.h>	/* We need sk_buff_head. */
59 #include <linux/workqueue.h>	/* We need tq_struct.	 */
60 #include <linux/sctp.h>		/* We need sctp* header structs.  */
61 #include <net/sctp/auth.h>	/* We need auth specific structs */
62 #include <net/ip.h>		/* For inet_skb_parm */
63 
64 /* A convenience structure for handling sockaddr structures.
65  * We should wean ourselves off this.
66  */
67 union sctp_addr {
68 	struct sockaddr_in v4;
69 	struct sockaddr_in6 v6;
70 	struct sockaddr sa;
71 };
72 
73 /* Forward declarations for data structures. */
74 struct sctp_globals;
75 struct sctp_endpoint;
76 struct sctp_association;
77 struct sctp_transport;
78 struct sctp_packet;
79 struct sctp_chunk;
80 struct sctp_inq;
81 struct sctp_outq;
82 struct sctp_bind_addr;
83 struct sctp_ulpq;
84 struct sctp_ep_common;
85 struct crypto_shash;
86 
87 
88 #include <net/sctp/tsnmap.h>
89 #include <net/sctp/ulpevent.h>
90 #include <net/sctp/ulpqueue.h>
91 
92 /* Structures useful for managing bind/connect. */
93 
94 struct sctp_bind_bucket {
95 	unsigned short	port;
96 	unsigned short	fastreuse;
97 	struct hlist_node	node;
98 	struct hlist_head	owner;
99 	struct net	*net;
100 };
101 
102 struct sctp_bind_hashbucket {
103 	spinlock_t	lock;
104 	struct hlist_head	chain;
105 };
106 
107 /* Used for hashing all associations.  */
108 struct sctp_hashbucket {
109 	rwlock_t	lock;
110 	struct hlist_head	chain;
111 } __attribute__((__aligned__(8)));
112 
113 
114 /* The SCTP globals structure. */
115 extern struct sctp_globals {
116 	/* This is a list of groups of functions for each address
117 	 * family that we support.
118 	 */
119 	struct list_head address_families;
120 
121 	/* This is the hash of all endpoints. */
122 	struct sctp_hashbucket *ep_hashtable;
123 	/* This is the sctp port control hash.	*/
124 	struct sctp_bind_hashbucket *port_hashtable;
125 	/* This is the hash of all transports. */
126 	struct rhltable transport_hashtable;
127 
128 	/* Sizes of above hashtables. */
129 	int ep_hashsize;
130 	int port_hashsize;
131 
132 	/* Default initialization values to be applied to new associations. */
133 	__u16 max_instreams;
134 	__u16 max_outstreams;
135 
136 	/* Flag to indicate whether computing and verifying checksum
137 	 * is disabled. */
138         bool checksum_disable;
139 } sctp_globals;
140 
141 #define sctp_max_instreams		(sctp_globals.max_instreams)
142 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
143 #define sctp_address_families		(sctp_globals.address_families)
144 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
145 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
146 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
147 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
148 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
149 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
150 
151 /* SCTP Socket type: UDP or TCP style. */
152 typedef enum {
153 	SCTP_SOCKET_UDP = 0,
154 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
155 	SCTP_SOCKET_TCP
156 } sctp_socket_type_t;
157 
158 /* Per socket SCTP information. */
159 struct sctp_sock {
160 	/* inet_sock has to be the first member of sctp_sock */
161 	struct inet_sock inet;
162 	/* What kind of a socket is this? */
163 	sctp_socket_type_t type;
164 
165 	/* PF_ family specific functions.  */
166 	struct sctp_pf *pf;
167 
168 	/* Access to HMAC transform. */
169 	struct crypto_shash *hmac;
170 	char *sctp_hmac_alg;
171 
172 	/* What is our base endpointer? */
173 	struct sctp_endpoint *ep;
174 
175 	struct sctp_bind_bucket *bind_hash;
176 	/* Various Socket Options.  */
177 	__u16 default_stream;
178 	__u32 default_ppid;
179 	__u16 default_flags;
180 	__u32 default_context;
181 	__u32 default_timetolive;
182 	__u32 default_rcv_context;
183 	int max_burst;
184 
185 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
186 	 * the destination address every heartbeat interval. This value
187 	 * will be inherited by all new associations.
188 	 */
189 	__u32 hbinterval;
190 
191 	/* This is the max_retrans value for new associations. */
192 	__u16 pathmaxrxt;
193 
194 	/* The initial Path MTU to use for new associations. */
195 	__u32 pathmtu;
196 
197 	/* The default SACK delay timeout for new associations. */
198 	__u32 sackdelay;
199 	__u32 sackfreq;
200 
201 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
202 	__u32 param_flags;
203 
204 	struct sctp_initmsg initmsg;
205 	struct sctp_rtoinfo rtoinfo;
206 	struct sctp_paddrparams paddrparam;
207 	struct sctp_event_subscribe subscribe;
208 	struct sctp_assocparams assocparams;
209 
210 	int user_frag;
211 
212 	__u32 autoclose;
213 	__u32 adaptation_ind;
214 	__u32 pd_point;
215 	__u16	nodelay:1,
216 		disable_fragments:1,
217 		v4mapped:1,
218 		frag_interleave:1,
219 		recvrcvinfo:1,
220 		recvnxtinfo:1,
221 		data_ready_signalled:1;
222 
223 	atomic_t pd_mode;
224 	/* Receive to here while partial delivery is in effect. */
225 	struct sk_buff_head pd_lobby;
226 
227 	/* These must be the last fields, as they will skipped on copies,
228 	 * like on accept and peeloff operations
229 	 */
230 	struct list_head auto_asconf_list;
231 	int do_auto_asconf;
232 };
233 
234 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
235 {
236        return (struct sctp_sock *)sk;
237 }
238 
239 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
240 {
241        return (struct sock *)sp;
242 }
243 
244 #if IS_ENABLED(CONFIG_IPV6)
245 struct sctp6_sock {
246        struct sctp_sock  sctp;
247        struct ipv6_pinfo inet6;
248 };
249 #endif /* CONFIG_IPV6 */
250 
251 
252 /* This is our APPLICATION-SPECIFIC state cookie.
253  * THIS IS NOT DICTATED BY THE SPECIFICATION.
254  */
255 /* These are the parts of an association which we send in the cookie.
256  * Most of these are straight out of:
257  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
258  *
259  */
260 
261 struct sctp_cookie {
262 
263 	/* My	       : Tag expected in every inbound packet and sent
264 	 * Verification: in the INIT or INIT ACK chunk.
265 	 * Tag	       :
266 	 */
267 	__u32 my_vtag;
268 
269 	/* Peer's      : Tag expected in every outbound packet except
270 	 * Verification: in the INIT chunk.
271 	 * Tag	       :
272 	 */
273 	__u32 peer_vtag;
274 
275 	/* The rest of these are not from the spec, but really need to
276 	 * be in the cookie.
277 	 */
278 
279 	/* My Tie Tag  : Assist in discovering a restarting association. */
280 	__u32 my_ttag;
281 
282 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
283 	__u32 peer_ttag;
284 
285 	/* When does this cookie expire? */
286 	ktime_t expiration;
287 
288 	/* Number of inbound/outbound streams which are set
289 	 * and negotiated during the INIT process.
290 	 */
291 	__u16 sinit_num_ostreams;
292 	__u16 sinit_max_instreams;
293 
294 	/* This is the first sequence number I used.  */
295 	__u32 initial_tsn;
296 
297 	/* This holds the originating address of the INIT packet.  */
298 	union sctp_addr peer_addr;
299 
300 	/* IG Section 2.35.3
301 	 * Include the source port of the INIT-ACK
302 	 */
303 	__u16		my_port;
304 
305 	__u8 prsctp_capable;
306 
307 	/* Padding for future use */
308 	__u8 padding;
309 
310 	__u32 adaptation_ind;
311 
312 	__u8 auth_random[sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH];
313 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
314 	__u8 auth_chunks[sizeof(sctp_paramhdr_t) + SCTP_AUTH_MAX_CHUNKS];
315 
316 	/* This is a shim for my peer's INIT packet, followed by
317 	 * a copy of the raw address list of the association.
318 	 * The length of the raw address list is saved in the
319 	 * raw_addr_list_len field, which will be used at the time when
320 	 * the association TCB is re-constructed from the cookie.
321 	 */
322 	__u32 raw_addr_list_len;
323 	struct sctp_init_chunk peer_init[0];
324 };
325 
326 
327 /* The format of our cookie that we send to our peer. */
328 struct sctp_signed_cookie {
329 	__u8 signature[SCTP_SECRET_SIZE];
330 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
331 	struct sctp_cookie c;
332 } __packed;
333 
334 /* This is another convenience type to allocate memory for address
335  * params for the maximum size and pass such structures around
336  * internally.
337  */
338 union sctp_addr_param {
339 	struct sctp_paramhdr p;
340 	struct sctp_ipv4addr_param v4;
341 	struct sctp_ipv6addr_param v6;
342 };
343 
344 /* A convenience type to allow walking through the various
345  * parameters and avoid casting all over the place.
346  */
347 union sctp_params {
348 	void *v;
349 	struct sctp_paramhdr *p;
350 	struct sctp_cookie_preserve_param *life;
351 	struct sctp_hostname_param *dns;
352 	struct sctp_cookie_param *cookie;
353 	struct sctp_supported_addrs_param *sat;
354 	struct sctp_ipv4addr_param *v4;
355 	struct sctp_ipv6addr_param *v6;
356 	union sctp_addr_param *addr;
357 	struct sctp_adaptation_ind_param *aind;
358 	struct sctp_supported_ext_param *ext;
359 	struct sctp_random_param *random;
360 	struct sctp_chunks_param *chunks;
361 	struct sctp_hmac_algo_param *hmac_algo;
362 	struct sctp_addip_param *addip;
363 };
364 
365 /* RFC 2960.  Section 3.3.5 Heartbeat.
366  *    Heartbeat Information: variable length
367  *    The Sender-specific Heartbeat Info field should normally include
368  *    information about the sender's current time when this HEARTBEAT
369  *    chunk is sent and the destination transport address to which this
370  *    HEARTBEAT is sent (see Section 8.3).
371  */
372 typedef struct sctp_sender_hb_info {
373 	struct sctp_paramhdr param_hdr;
374 	union sctp_addr daddr;
375 	unsigned long sent_at;
376 	__u64 hb_nonce;
377 } sctp_sender_hb_info_t;
378 
379 struct sctp_stream *sctp_stream_new(__u16 incnt, __u16 outcnt, gfp_t gfp);
380 void sctp_stream_free(struct sctp_stream *stream);
381 void sctp_stream_clear(struct sctp_stream *stream);
382 
383 /* What is the current SSN number for this stream? */
384 #define sctp_ssn_peek(stream, type, sid) \
385 	((stream)->type[sid].ssn)
386 
387 /* Return the next SSN number for this stream.	*/
388 #define sctp_ssn_next(stream, type, sid) \
389 	((stream)->type[sid].ssn++)
390 
391 /* Skip over this ssn and all below. */
392 #define sctp_ssn_skip(stream, type, sid, ssn) \
393 	((stream)->type[sid].ssn = ssn + 1)
394 
395 /*
396  * Pointers to address related SCTP functions.
397  * (i.e. things that depend on the address family.)
398  */
399 struct sctp_af {
400 	int		(*sctp_xmit)	(struct sk_buff *skb,
401 					 struct sctp_transport *);
402 	int		(*setsockopt)	(struct sock *sk,
403 					 int level,
404 					 int optname,
405 					 char __user *optval,
406 					 unsigned int optlen);
407 	int		(*getsockopt)	(struct sock *sk,
408 					 int level,
409 					 int optname,
410 					 char __user *optval,
411 					 int __user *optlen);
412 	int		(*compat_setsockopt)	(struct sock *sk,
413 					 int level,
414 					 int optname,
415 					 char __user *optval,
416 					 unsigned int optlen);
417 	int		(*compat_getsockopt)	(struct sock *sk,
418 					 int level,
419 					 int optname,
420 					 char __user *optval,
421 					 int __user *optlen);
422 	void		(*get_dst)	(struct sctp_transport *t,
423 					 union sctp_addr *saddr,
424 					 struct flowi *fl,
425 					 struct sock *sk);
426 	void		(*get_saddr)	(struct sctp_sock *sk,
427 					 struct sctp_transport *t,
428 					 struct flowi *fl);
429 	void		(*copy_addrlist) (struct list_head *,
430 					  struct net_device *);
431 	int		(*cmp_addr)	(const union sctp_addr *addr1,
432 					 const union sctp_addr *addr2);
433 	void		(*addr_copy)	(union sctp_addr *dst,
434 					 union sctp_addr *src);
435 	void		(*from_skb)	(union sctp_addr *,
436 					 struct sk_buff *skb,
437 					 int saddr);
438 	void		(*from_sk)	(union sctp_addr *,
439 					 struct sock *sk);
440 	void		(*from_addr_param) (union sctp_addr *,
441 					    union sctp_addr_param *,
442 					    __be16 port, int iif);
443 	int		(*to_addr_param) (const union sctp_addr *,
444 					  union sctp_addr_param *);
445 	int		(*addr_valid)	(union sctp_addr *,
446 					 struct sctp_sock *,
447 					 const struct sk_buff *);
448 	sctp_scope_t	(*scope) (union sctp_addr *);
449 	void		(*inaddr_any)	(union sctp_addr *, __be16);
450 	int		(*is_any)	(const union sctp_addr *);
451 	int		(*available)	(union sctp_addr *,
452 					 struct sctp_sock *);
453 	int		(*skb_iif)	(const struct sk_buff *sk);
454 	int		(*is_ce)	(const struct sk_buff *sk);
455 	void		(*seq_dump_addr)(struct seq_file *seq,
456 					 union sctp_addr *addr);
457 	void		(*ecn_capable)(struct sock *sk);
458 	__u16		net_header_len;
459 	int		sockaddr_len;
460 	sa_family_t	sa_family;
461 	struct list_head list;
462 };
463 
464 struct sctp_af *sctp_get_af_specific(sa_family_t);
465 int sctp_register_af(struct sctp_af *);
466 
467 /* Protocol family functions. */
468 struct sctp_pf {
469 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
470 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
471 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
472 	int  (*cmp_addr) (const union sctp_addr *,
473 			  const union sctp_addr *,
474 			  struct sctp_sock *);
475 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
476 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
477 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
478 	struct sock *(*create_accept_sk) (struct sock *sk,
479 					  struct sctp_association *asoc);
480 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
481 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
482 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
483 	struct sctp_af *af;
484 };
485 
486 
487 /* Structure to track chunk fragments that have been acked, but peer
488  * fragments of the same message have not.
489  */
490 struct sctp_datamsg {
491 	/* Chunks waiting to be submitted to lower layer. */
492 	struct list_head chunks;
493 	/* Reference counting. */
494 	atomic_t refcnt;
495 	/* When is this message no longer interesting to the peer? */
496 	unsigned long expires_at;
497 	/* Did the messenge fail to send? */
498 	int send_error;
499 	u8 send_failed:1,
500 	   force_delay:1,
501 	   can_delay;	    /* should this message be Nagle delayed */
502 };
503 
504 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
505 					    struct sctp_sndrcvinfo *,
506 					    struct iov_iter *);
507 void sctp_datamsg_free(struct sctp_datamsg *);
508 void sctp_datamsg_put(struct sctp_datamsg *);
509 void sctp_chunk_fail(struct sctp_chunk *, int error);
510 int sctp_chunk_abandoned(struct sctp_chunk *);
511 
512 /* RFC2960 1.4 Key Terms
513  *
514  * o Chunk: A unit of information within an SCTP packet, consisting of
515  * a chunk header and chunk-specific content.
516  *
517  * As a matter of convenience, we remember the SCTP common header for
518  * each chunk as well as a few other header pointers...
519  */
520 struct sctp_chunk {
521 	struct list_head list;
522 
523 	atomic_t refcnt;
524 
525 	/* How many times this chunk have been sent, for prsctp RTX policy */
526 	int sent_count;
527 
528 	/* This is our link to the per-transport transmitted list.  */
529 	struct list_head transmitted_list;
530 
531 	/* This field is used by chunks that hold fragmented data.
532 	 * For the first fragment this is the list that holds the rest of
533 	 * fragments. For the remaining fragments, this is the link to the
534 	 * frag_list maintained in the first fragment.
535 	 */
536 	struct list_head frag_list;
537 
538 	/* This points to the sk_buff containing the actual data.  */
539 	struct sk_buff *skb;
540 
541 	/* In case of GSO packets, this will store the head one */
542 	struct sk_buff *head_skb;
543 
544 	/* These are the SCTP headers by reverse order in a packet.
545 	 * Note that some of these may happen more than once.  In that
546 	 * case, we point at the "current" one, whatever that means
547 	 * for that level of header.
548 	 */
549 
550 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
551 	union sctp_params param_hdr;
552 	union {
553 		__u8 *v;
554 		struct sctp_datahdr *data_hdr;
555 		struct sctp_inithdr *init_hdr;
556 		struct sctp_sackhdr *sack_hdr;
557 		struct sctp_heartbeathdr *hb_hdr;
558 		struct sctp_sender_hb_info *hbs_hdr;
559 		struct sctp_shutdownhdr *shutdown_hdr;
560 		struct sctp_signed_cookie *cookie_hdr;
561 		struct sctp_ecnehdr *ecne_hdr;
562 		struct sctp_cwrhdr *ecn_cwr_hdr;
563 		struct sctp_errhdr *err_hdr;
564 		struct sctp_addiphdr *addip_hdr;
565 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
566 		struct sctp_authhdr *auth_hdr;
567 	} subh;
568 
569 	__u8 *chunk_end;
570 
571 	struct sctp_chunkhdr *chunk_hdr;
572 	struct sctphdr *sctp_hdr;
573 
574 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
575 	struct sctp_sndrcvinfo sinfo;
576 
577 	/* Which association does this belong to?  */
578 	struct sctp_association *asoc;
579 
580 	/* What endpoint received this chunk? */
581 	struct sctp_ep_common *rcvr;
582 
583 	/* We fill this in if we are calculating RTT. */
584 	unsigned long sent_at;
585 
586 	/* What is the origin IP address for this chunk?  */
587 	union sctp_addr source;
588 	/* Destination address for this chunk. */
589 	union sctp_addr dest;
590 
591 	/* For outbound message, track all fragments for SEND_FAILED. */
592 	struct sctp_datamsg *msg;
593 
594 	/* For an inbound chunk, this tells us where it came from.
595 	 * For an outbound chunk, it tells us where we'd like it to
596 	 * go.	It is NULL if we have no preference.
597 	 */
598 	struct sctp_transport *transport;
599 
600 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
601 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
602 	 * spec violates the principle premis that all chunks are processed
603 	 * in order.
604 	 */
605 	struct sk_buff *auth_chunk;
606 
607 #define SCTP_CAN_FRTX 0x0
608 #define SCTP_NEED_FRTX 0x1
609 #define SCTP_DONT_FRTX 0x2
610 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
611 		has_tsn:1,		/* Does this chunk have a TSN yet? */
612 		has_ssn:1,		/* Does this chunk have a SSN yet? */
613 		singleton:1,		/* Only chunk in the packet? */
614 		end_of_packet:1,	/* Last chunk in the packet? */
615 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
616 		pdiscard:1,		/* Discard the whole packet now? */
617 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
618 		data_accepted:1,	/* At least 1 chunk accepted */
619 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
620 		has_asconf:1,		/* IN: have seen an asconf before */
621 		tsn_missing_report:2,	/* Data chunk missing counter. */
622 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
623 };
624 
625 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
626 void sctp_chunk_hold(struct sctp_chunk *);
627 void sctp_chunk_put(struct sctp_chunk *);
628 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
629 			  struct iov_iter *from);
630 void sctp_chunk_free(struct sctp_chunk *);
631 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
632 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
633 				 const struct sctp_association *,
634 				 struct sock *, gfp_t gfp);
635 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
636 		     union sctp_addr *);
637 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
638 
639 enum {
640 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
641 	SCTP_ADDR_SRC,		/* address can be used as source */
642 	SCTP_ADDR_DEL,		/* address about to be deleted */
643 };
644 
645 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
646 struct sctp_sockaddr_entry {
647 	struct list_head list;
648 	struct rcu_head	rcu;
649 	union sctp_addr a;
650 	__u8 state;
651 	__u8 valid;
652 };
653 
654 #define SCTP_ADDRESS_TICK_DELAY	500
655 
656 typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);
657 
658 /* This structure holds lists of chunks as we are assembling for
659  * transmission.
660  */
661 struct sctp_packet {
662 	/* These are the SCTP header values (host order) for the packet. */
663 	__u16 source_port;
664 	__u16 destination_port;
665 	__u32 vtag;
666 
667 	/* This contains the payload chunks.  */
668 	struct list_head chunk_list;
669 
670 	/* This is the overhead of the sctp and ip headers. */
671 	size_t overhead;
672 	/* This is the total size of all chunks INCLUDING padding.  */
673 	size_t size;
674 	/* This is the maximum size this packet may have */
675 	size_t max_size;
676 
677 	/* The packet is destined for this transport address.
678 	 * The function we finally use to pass down to the next lower
679 	 * layer lives in the transport structure.
680 	 */
681 	struct sctp_transport *transport;
682 
683 	/* pointer to the auth chunk for this packet */
684 	struct sctp_chunk *auth;
685 
686 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
687 	    has_sack:1,		/* This packet contains a SACK chunk. */
688 	    has_auth:1,		/* This packet contains an AUTH chunk */
689 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
690 	    ipfragok:1;		/* So let ip fragment this packet */
691 };
692 
693 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
694 		      __u16 sport, __u16 dport);
695 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
696 sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *,
697 				       struct sctp_chunk *, int, gfp_t);
698 sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *,
699                                      struct sctp_chunk *);
700 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
701 void sctp_packet_free(struct sctp_packet *);
702 
703 static inline int sctp_packet_empty(struct sctp_packet *packet)
704 {
705 	return packet->size == packet->overhead;
706 }
707 
708 /* This represents a remote transport address.
709  * For local transport addresses, we just use union sctp_addr.
710  *
711  * RFC2960 Section 1.4 Key Terms
712  *
713  *   o	Transport address:  A Transport Address is traditionally defined
714  *	by Network Layer address, Transport Layer protocol and Transport
715  *	Layer port number.  In the case of SCTP running over IP, a
716  *	transport address is defined by the combination of an IP address
717  *	and an SCTP port number (where SCTP is the Transport protocol).
718  *
719  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
720  *
721  *   o	The sender keeps a separate congestion control parameter set for
722  *	each of the destination addresses it can send to (not each
723  *	source-destination pair but for each destination).  The parameters
724  *	should decay if the address is not used for a long enough time
725  *	period.
726  *
727  */
728 struct sctp_transport {
729 	/* A list of transports. */
730 	struct list_head transports;
731 	struct rhlist_head node;
732 
733 	/* Reference counting. */
734 	atomic_t refcnt;
735 		/* RTO-Pending : A flag used to track if one of the DATA
736 		 *		chunks sent to this address is currently being
737 		 *		used to compute a RTT. If this flag is 0,
738 		 *		the next DATA chunk sent to this destination
739 		 *		should be used to compute a RTT and this flag
740 		 *		should be set. Every time the RTT
741 		 *		calculation completes (i.e. the DATA chunk
742 		 *		is SACK'd) clear this flag.
743 		 */
744 	__u32	rto_pending:1,
745 
746 		/*
747 		 * hb_sent : a flag that signals that we have a pending
748 		 * heartbeat.
749 		 */
750 		hb_sent:1,
751 
752 		/* Is the Path MTU update pending on this tranport */
753 		pmtu_pending:1,
754 
755 		/* Has this transport moved the ctsn since we last sacked */
756 		sack_generation:1;
757 	u32 dst_cookie;
758 
759 	struct flowi fl;
760 
761 	/* This is the peer's IP address and port. */
762 	union sctp_addr ipaddr;
763 
764 	/* These are the functions we call to handle LLP stuff.	 */
765 	struct sctp_af *af_specific;
766 
767 	/* Which association do we belong to?  */
768 	struct sctp_association *asoc;
769 
770 	/* RFC2960
771 	 *
772 	 * 12.3 Per Transport Address Data
773 	 *
774 	 * For each destination transport address in the peer's
775 	 * address list derived from the INIT or INIT ACK chunk, a
776 	 * number of data elements needs to be maintained including:
777 	 */
778 	/* RTO	       : The current retransmission timeout value.  */
779 	unsigned long rto;
780 
781 	__u32 rtt;		/* This is the most recent RTT.	 */
782 
783 	/* RTTVAR      : The current RTT variation.  */
784 	__u32 rttvar;
785 
786 	/* SRTT	       : The current smoothed round trip time.	*/
787 	__u32 srtt;
788 
789 	/*
790 	 * These are the congestion stats.
791 	 */
792 	/* cwnd	       : The current congestion window.	 */
793 	__u32 cwnd;		  /* This is the actual cwnd.  */
794 
795 	/* ssthresh    : The current slow start threshold value.  */
796 	__u32 ssthresh;
797 
798 	/* partial     : The tracking method for increase of cwnd when in
799 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
800 	 */
801 	__u32 partial_bytes_acked;
802 
803 	/* Data that has been sent, but not acknowledged. */
804 	__u32 flight_size;
805 
806 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
807 
808 	__u32 dst_pending_confirm;	/* need to confirm neighbour */
809 
810 	/* Destination */
811 	struct dst_entry *dst;
812 	/* Source address. */
813 	union sctp_addr saddr;
814 
815 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
816 	 * the destination address every heartbeat interval.
817 	 */
818 	unsigned long hbinterval;
819 
820 	/* SACK delay timeout */
821 	unsigned long sackdelay;
822 	__u32 sackfreq;
823 
824 	/* When was the last time that we heard from this transport? We use
825 	 * this to pick new active and retran paths.
826 	 */
827 	ktime_t last_time_heard;
828 
829 	/* When was the last time that we sent a chunk using this
830 	 * transport? We use this to check for idle transports
831 	 */
832 	unsigned long last_time_sent;
833 
834 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
835 	 * indication based on ECNE chunk.
836 	 */
837 	unsigned long last_time_ecne_reduced;
838 
839 	/* This is the max_retrans value for the transport and will
840 	 * be initialized from the assocs value.  This can be changed
841 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
842 	 */
843 	__u16 pathmaxrxt;
844 
845 	/* This is the partially failed retrans value for the transport
846 	 * and will be initialized from the assocs value.  This can be changed
847 	 * using the SCTP_PEER_ADDR_THLDS socket option
848 	 */
849 	int pf_retrans;
850 	/* PMTU	      : The current known path MTU.  */
851 	__u32 pathmtu;
852 
853 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
854 	__u32 param_flags;
855 
856 	/* The number of times INIT has been sent on this transport. */
857 	int init_sent_count;
858 
859 	/* state       : The current state of this destination,
860 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
861 	 */
862 	int state;
863 
864 	/* These are the error stats for this destination.  */
865 
866 	/* Error count : The current error count for this destination.	*/
867 	unsigned short error_count;
868 
869 	/* Per	       : A timer used by each destination.
870 	 * Destination :
871 	 * Timer       :
872 	 *
873 	 * [Everywhere else in the text this is called T3-rtx. -ed]
874 	 */
875 	struct timer_list T3_rtx_timer;
876 
877 	/* Heartbeat timer is per destination. */
878 	struct timer_list hb_timer;
879 
880 	/* Timer to handle ICMP proto unreachable envets */
881 	struct timer_list proto_unreach_timer;
882 
883 	/* Timer to handler reconf chunk rtx */
884 	struct timer_list reconf_timer;
885 
886 	/* Since we're using per-destination retransmission timers
887 	 * (see above), we're also using per-destination "transmitted"
888 	 * queues.  This probably ought to be a private struct
889 	 * accessible only within the outqueue, but it's not, yet.
890 	 */
891 	struct list_head transmitted;
892 
893 	/* We build bundle-able packets for this transport here.  */
894 	struct sctp_packet packet;
895 
896 	/* This is the list of transports that have chunks to send.  */
897 	struct list_head send_ready;
898 
899 	/* State information saved for SFR_CACC algorithm. The key
900 	 * idea in SFR_CACC is to maintain state at the sender on a
901 	 * per-destination basis when a changeover happens.
902 	 *	char changeover_active;
903 	 *	char cycling_changeover;
904 	 *	__u32 next_tsn_at_change;
905 	 *	char cacc_saw_newack;
906 	 */
907 	struct {
908 		/* An unsigned integer, which stores the next TSN to be
909 		 * used by the sender, at the moment of changeover.
910 		 */
911 		__u32 next_tsn_at_change;
912 
913 		/* A flag which indicates the occurrence of a changeover */
914 		char changeover_active;
915 
916 		/* A flag which indicates whether the change of primary is
917 		 * the first switch to this destination address during an
918 		 * active switch.
919 		 */
920 		char cycling_changeover;
921 
922 		/* A temporary flag, which is used during the processing of
923 		 * a SACK to estimate the causative TSN(s)'s group.
924 		 */
925 		char cacc_saw_newack;
926 	} cacc;
927 
928 	/* 64-bit random number sent with heartbeat. */
929 	__u64 hb_nonce;
930 
931 	struct rcu_head rcu;
932 };
933 
934 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
935 					  gfp_t);
936 void sctp_transport_set_owner(struct sctp_transport *,
937 			      struct sctp_association *);
938 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
939 			  struct sctp_sock *);
940 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
941 void sctp_transport_free(struct sctp_transport *);
942 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
943 void sctp_transport_reset_hb_timer(struct sctp_transport *);
944 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
945 int sctp_transport_hold(struct sctp_transport *);
946 void sctp_transport_put(struct sctp_transport *);
947 void sctp_transport_update_rto(struct sctp_transport *, __u32);
948 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
949 void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
950 void sctp_transport_burst_limited(struct sctp_transport *);
951 void sctp_transport_burst_reset(struct sctp_transport *);
952 unsigned long sctp_transport_timeout(struct sctp_transport *);
953 void sctp_transport_reset(struct sctp_transport *);
954 void sctp_transport_update_pmtu(struct sock *, struct sctp_transport *, u32);
955 void sctp_transport_immediate_rtx(struct sctp_transport *);
956 void sctp_transport_dst_release(struct sctp_transport *t);
957 void sctp_transport_dst_confirm(struct sctp_transport *t);
958 
959 
960 /* This is the structure we use to queue packets as they come into
961  * SCTP.  We write packets to it and read chunks from it.
962  */
963 struct sctp_inq {
964 	/* This is actually a queue of sctp_chunk each
965 	 * containing a partially decoded packet.
966 	 */
967 	struct list_head in_chunk_list;
968 	/* This is the packet which is currently off the in queue and is
969 	 * being worked on through the inbound chunk processing.
970 	 */
971 	struct sctp_chunk *in_progress;
972 
973 	/* This is the delayed task to finish delivering inbound
974 	 * messages.
975 	 */
976 	struct work_struct immediate;
977 };
978 
979 void sctp_inq_init(struct sctp_inq *);
980 void sctp_inq_free(struct sctp_inq *);
981 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
982 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
983 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
984 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
985 
986 /* This is the structure we use to hold outbound chunks.  You push
987  * chunks in and they automatically pop out the other end as bundled
988  * packets (it calls (*output_handler)()).
989  *
990  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
991  * and 8.2 of the v13 draft.
992  *
993  * It handles retransmissions.	The connection to the timeout portion
994  * of the state machine is through sctp_..._timeout() and timeout_handler.
995  *
996  * If you feed it SACKs, it will eat them.
997  *
998  * If you give it big chunks, it will fragment them.
999  *
1000  * It assigns TSN's to data chunks.  This happens at the last possible
1001  * instant before transmission.
1002  *
1003  * When free()'d, it empties itself out via output_handler().
1004  */
1005 struct sctp_outq {
1006 	struct sctp_association *asoc;
1007 
1008 	/* Data pending that has never been transmitted.  */
1009 	struct list_head out_chunk_list;
1010 
1011 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1012 
1013 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1014 	unsigned int error;
1015 
1016 	/* These are control chunks we want to send.  */
1017 	struct list_head control_chunk_list;
1018 
1019 	/* These are chunks that have been sacked but are above the
1020 	 * CTSN, or cumulative tsn ack point.
1021 	 */
1022 	struct list_head sacked;
1023 
1024 	/* Put chunks on this list to schedule them for
1025 	 * retransmission.
1026 	 */
1027 	struct list_head retransmit;
1028 
1029 	/* Put chunks on this list to save them for FWD TSN processing as
1030 	 * they were abandoned.
1031 	 */
1032 	struct list_head abandoned;
1033 
1034 	/* How many unackd bytes do we have in-flight?	*/
1035 	__u32 outstanding_bytes;
1036 
1037 	/* Are we doing fast-rtx on this queue */
1038 	char fast_rtx;
1039 
1040 	/* Corked? */
1041 	char cork;
1042 };
1043 
1044 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1045 void sctp_outq_teardown(struct sctp_outq *);
1046 void sctp_outq_free(struct sctp_outq*);
1047 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1048 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1049 int sctp_outq_is_empty(const struct sctp_outq *);
1050 void sctp_outq_restart(struct sctp_outq *);
1051 
1052 void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
1053 		     sctp_retransmit_reason_t);
1054 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1055 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1056 void sctp_prsctp_prune(struct sctp_association *asoc,
1057 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1058 /* Uncork and flush an outqueue.  */
1059 static inline void sctp_outq_cork(struct sctp_outq *q)
1060 {
1061 	q->cork = 1;
1062 }
1063 
1064 /* SCTP skb control block.
1065  * sctp_input_cb is currently used on rx and sock rx queue
1066  */
1067 struct sctp_input_cb {
1068 	union {
1069 		struct inet_skb_parm	h4;
1070 #if IS_ENABLED(CONFIG_IPV6)
1071 		struct inet6_skb_parm	h6;
1072 #endif
1073 	} header;
1074 	struct sctp_chunk *chunk;
1075 	struct sctp_af *af;
1076 };
1077 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1078 
1079 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1080 {
1081 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1082 
1083 	return chunk->head_skb ? : skb;
1084 }
1085 
1086 /* These bind address data fields common between endpoints and associations */
1087 struct sctp_bind_addr {
1088 
1089 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1090 	 *
1091 	 * SCTP Port:	The local SCTP port number the endpoint is
1092 	 *		bound to.
1093 	 */
1094 	__u16 port;
1095 
1096 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1097 	 *
1098 	 * Address List: The list of IP addresses that this instance
1099 	 *	has bound.  This information is passed to one's
1100 	 *	peer(s) in INIT and INIT ACK chunks.
1101 	 */
1102 	struct list_head address_list;
1103 };
1104 
1105 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1106 void sctp_bind_addr_free(struct sctp_bind_addr *);
1107 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1108 			const struct sctp_bind_addr *src,
1109 			sctp_scope_t scope, gfp_t gfp,
1110 			int flags);
1111 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1112 			const struct sctp_bind_addr *src,
1113 			gfp_t gfp);
1114 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1115 		       int new_size, __u8 addr_state, gfp_t gfp);
1116 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1117 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1118 			 struct sctp_sock *);
1119 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1120 			 struct sctp_sock *, struct sctp_sock *);
1121 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1122 			 const union sctp_addr *addr);
1123 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1124 					const union sctp_addr	*addrs,
1125 					int			addrcnt,
1126 					struct sctp_sock	*opt);
1127 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1128 					 int *addrs_len,
1129 					 gfp_t gfp);
1130 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1131 			   __u16 port, gfp_t gfp);
1132 
1133 sctp_scope_t sctp_scope(const union sctp_addr *);
1134 int sctp_in_scope(struct net *net, const union sctp_addr *addr, const sctp_scope_t scope);
1135 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1136 int sctp_is_ep_boundall(struct sock *sk);
1137 
1138 
1139 /* What type of endpoint?  */
1140 typedef enum {
1141 	SCTP_EP_TYPE_SOCKET,
1142 	SCTP_EP_TYPE_ASSOCIATION,
1143 } sctp_endpoint_type_t;
1144 
1145 /*
1146  * A common base class to bridge the implmentation view of a
1147  * socket (usually listening) endpoint versus an association's
1148  * local endpoint.
1149  * This common structure is useful for several purposes:
1150  *   1) Common interface for lookup routines.
1151  *	a) Subfunctions work for either endpoint or association
1152  *	b) Single interface to lookup allows hiding the lookup lock rather
1153  *	   than acquiring it externally.
1154  *   2) Common interface for the inbound chunk handling/state machine.
1155  *   3) Common object handling routines for reference counting, etc.
1156  *   4) Disentangle association lookup from endpoint lookup, where we
1157  *	do not have to find our endpoint to find our association.
1158  *
1159  */
1160 
1161 struct sctp_ep_common {
1162 	/* Fields to help us manage our entries in the hash tables. */
1163 	struct hlist_node node;
1164 	int hashent;
1165 
1166 	/* Runtime type information.  What kind of endpoint is this? */
1167 	sctp_endpoint_type_t type;
1168 
1169 	/* Some fields to help us manage this object.
1170 	 *   refcnt   - Reference count access to this object.
1171 	 *   dead     - Do not attempt to use this object.
1172 	 */
1173 	atomic_t    refcnt;
1174 	bool	    dead;
1175 
1176 	/* What socket does this endpoint belong to?  */
1177 	struct sock *sk;
1178 
1179 	/* This is where we receive inbound chunks.  */
1180 	struct sctp_inq	  inqueue;
1181 
1182 	/* This substructure includes the defining parameters of the
1183 	 * endpoint:
1184 	 * bind_addr.port is our shared port number.
1185 	 * bind_addr.address_list is our set of local IP addresses.
1186 	 */
1187 	struct sctp_bind_addr bind_addr;
1188 };
1189 
1190 
1191 /* RFC Section 1.4 Key Terms
1192  *
1193  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1194  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1195  *   combination of a set of eligible destination transport addresses to
1196  *   which SCTP packets can be sent and a set of eligible source
1197  *   transport addresses from which SCTP packets can be received.
1198  *   All transport addresses used by an SCTP endpoint must use the
1199  *   same port number, but can use multiple IP addresses. A transport
1200  *   address used by an SCTP endpoint must not be used by another
1201  *   SCTP endpoint. In other words, a transport address is unique
1202  *   to an SCTP endpoint.
1203  *
1204  * From an implementation perspective, each socket has one of these.
1205  * A TCP-style socket will have exactly one association on one of
1206  * these.  An UDP-style socket will have multiple associations hanging
1207  * off one of these.
1208  */
1209 
1210 struct sctp_endpoint {
1211 	/* Common substructure for endpoint and association. */
1212 	struct sctp_ep_common base;
1213 
1214 	/* Associations: A list of current associations and mappings
1215 	 *	      to the data consumers for each association. This
1216 	 *	      may be in the form of a hash table or other
1217 	 *	      implementation dependent structure. The data
1218 	 *	      consumers may be process identification
1219 	 *	      information such as file descriptors, named pipe
1220 	 *	      pointer, or table pointers dependent on how SCTP
1221 	 *	      is implemented.
1222 	 */
1223 	/* This is really a list of struct sctp_association entries. */
1224 	struct list_head asocs;
1225 
1226 	/* Secret Key: A secret key used by this endpoint to compute
1227 	 *	      the MAC.	This SHOULD be a cryptographic quality
1228 	 *	      random number with a sufficient length.
1229 	 *	      Discussion in [RFC1750] can be helpful in
1230 	 *	      selection of the key.
1231 	 */
1232 	__u8 secret_key[SCTP_SECRET_SIZE];
1233 
1234  	/* digest:  This is a digest of the sctp cookie.  This field is
1235  	 * 	    only used on the receive path when we try to validate
1236  	 * 	    that the cookie has not been tampered with.  We put
1237  	 * 	    this here so we pre-allocate this once and can re-use
1238  	 * 	    on every receive.
1239  	 */
1240  	__u8 *digest;
1241 
1242 	/* sendbuf acct. policy.	*/
1243 	__u32 sndbuf_policy;
1244 
1245 	/* rcvbuf acct. policy.	*/
1246 	__u32 rcvbuf_policy;
1247 
1248 	/* SCTP AUTH: array of the HMACs that will be allocated
1249 	 * we need this per association so that we don't serialize
1250 	 */
1251 	struct crypto_shash **auth_hmacs;
1252 
1253 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1254 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1255 
1256 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1257 	struct sctp_chunks_param *auth_chunk_list;
1258 
1259 	/* SCTP-AUTH: endpoint shared keys */
1260 	struct list_head endpoint_shared_keys;
1261 	__u16 active_key_id;
1262 	__u8  auth_enable:1,
1263 	      prsctp_enable:1,
1264 	      reconf_enable:1;
1265 
1266 	__u8  strreset_enable;
1267 };
1268 
1269 /* Recover the outter endpoint structure. */
1270 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1271 {
1272 	struct sctp_endpoint *ep;
1273 
1274 	ep = container_of(base, struct sctp_endpoint, base);
1275 	return ep;
1276 }
1277 
1278 /* These are function signatures for manipulating endpoints.  */
1279 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1280 void sctp_endpoint_free(struct sctp_endpoint *);
1281 void sctp_endpoint_put(struct sctp_endpoint *);
1282 void sctp_endpoint_hold(struct sctp_endpoint *);
1283 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1284 struct sctp_association *sctp_endpoint_lookup_assoc(
1285 	const struct sctp_endpoint *ep,
1286 	const union sctp_addr *paddr,
1287 	struct sctp_transport **);
1288 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1289 				const union sctp_addr *);
1290 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1291 					struct net *, const union sctp_addr *);
1292 int sctp_has_association(struct net *net, const union sctp_addr *laddr,
1293 			 const union sctp_addr *paddr);
1294 
1295 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1296 		     const struct sctp_association *asoc,
1297 		     sctp_cid_t, sctp_init_chunk_t *peer_init,
1298 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1299 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1300 		      const union sctp_addr *peer,
1301 		      sctp_init_chunk_t *init, gfp_t gfp);
1302 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1303 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1304 
1305 struct sctp_inithdr_host {
1306 	__u32 init_tag;
1307 	__u32 a_rwnd;
1308 	__u16 num_outbound_streams;
1309 	__u16 num_inbound_streams;
1310 	__u32 initial_tsn;
1311 };
1312 
1313 struct sctp_stream_out {
1314 	__u16	ssn;
1315 	__u8	state;
1316 };
1317 
1318 struct sctp_stream_in {
1319 	__u16	ssn;
1320 };
1321 
1322 struct sctp_stream {
1323 	struct sctp_stream_out *out;
1324 	struct sctp_stream_in *in;
1325 	__u16 outcnt;
1326 	__u16 incnt;
1327 };
1328 
1329 #define SCTP_STREAM_CLOSED		0x00
1330 #define SCTP_STREAM_OPEN		0x01
1331 
1332 /* SCTP_GET_ASSOC_STATS counters */
1333 struct sctp_priv_assoc_stats {
1334 	/* Maximum observed rto in the association during subsequent
1335 	 * observations. Value is set to 0 if no RTO measurement took place
1336 	 * The transport where the max_rto was observed is returned in
1337 	 * obs_rto_ipaddr
1338 	 */
1339 	struct sockaddr_storage obs_rto_ipaddr;
1340 	__u64 max_obs_rto;
1341 	/* Total In and Out SACKs received and sent */
1342 	__u64 isacks;
1343 	__u64 osacks;
1344 	/* Total In and Out packets received and sent */
1345 	__u64 opackets;
1346 	__u64 ipackets;
1347 	/* Total retransmitted chunks */
1348 	__u64 rtxchunks;
1349 	/* TSN received > next expected */
1350 	__u64 outofseqtsns;
1351 	/* Duplicate Chunks received */
1352 	__u64 idupchunks;
1353 	/* Gap Ack Blocks received */
1354 	__u64 gapcnt;
1355 	/* Unordered data chunks sent and received */
1356 	__u64 ouodchunks;
1357 	__u64 iuodchunks;
1358 	/* Ordered data chunks sent and received */
1359 	__u64 oodchunks;
1360 	__u64 iodchunks;
1361 	/* Control chunks sent and received */
1362 	__u64 octrlchunks;
1363 	__u64 ictrlchunks;
1364 };
1365 
1366 /* RFC2960
1367  *
1368  * 12. Recommended Transmission Control Block (TCB) Parameters
1369  *
1370  * This section details a recommended set of parameters that should
1371  * be contained within the TCB for an implementation. This section is
1372  * for illustrative purposes and should not be deemed as requirements
1373  * on an implementation or as an exhaustive list of all parameters
1374  * inside an SCTP TCB. Each implementation may need its own additional
1375  * parameters for optimization.
1376  */
1377 
1378 
1379 /* Here we have information about each individual association. */
1380 struct sctp_association {
1381 
1382 	/* A base structure common to endpoint and association.
1383 	 * In this context, it represents the associations's view
1384 	 * of the local endpoint of the association.
1385 	 */
1386 	struct sctp_ep_common base;
1387 
1388 	/* Associations on the same socket. */
1389 	struct list_head asocs;
1390 
1391 	/* association id. */
1392 	sctp_assoc_t assoc_id;
1393 
1394 	/* This is our parent endpoint.	 */
1395 	struct sctp_endpoint *ep;
1396 
1397 	/* These are those association elements needed in the cookie.  */
1398 	struct sctp_cookie c;
1399 
1400 	/* This is all information about our peer.  */
1401 	struct {
1402 		/* transport_addr_list
1403 		 *
1404 		 * Peer	       : A list of SCTP transport addresses that the
1405 		 * Transport   : peer is bound to. This information is derived
1406 		 * Address     : from the INIT or INIT ACK and is used to
1407 		 * List	       : associate an inbound packet with a given
1408 		 *	       : association. Normally this information is
1409 		 *	       : hashed or keyed for quick lookup and access
1410 		 *	       : of the TCB.
1411 		 *	       : The list is also initialized with the list
1412 		 *	       : of addresses passed with the sctp_connectx()
1413 		 *	       : call.
1414 		 *
1415 		 * It is a list of SCTP_transport's.
1416 		 */
1417 		struct list_head transport_addr_list;
1418 
1419 		/* rwnd
1420 		 *
1421 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1422 		 */
1423 		__u32 rwnd;
1424 
1425 		/* transport_count
1426 		 *
1427 		 * Peer        : A count of the number of peer addresses
1428 		 * Transport   : in the Peer Transport Address List.
1429 		 * Address     :
1430 		 * Count       :
1431 		 */
1432 		__u16 transport_count;
1433 
1434 		/* port
1435 		 *   The transport layer port number.
1436 		 */
1437 		__u16 port;
1438 
1439 		/* primary_path
1440 		 *
1441 		 * Primary     : This is the current primary destination
1442 		 * Path	       : transport address of the peer endpoint.  It
1443 		 *	       : may also specify a source transport address
1444 		 *	       : on this endpoint.
1445 		 *
1446 		 * All of these paths live on transport_addr_list.
1447 		 *
1448 		 * At the bakeoffs, we discovered that the intent of
1449 		 * primaryPath is that it only changes when the ULP
1450 		 * asks to have it changed.  We add the activePath to
1451 		 * designate the connection we are currently using to
1452 		 * transmit new data and most control chunks.
1453 		 */
1454 		struct sctp_transport *primary_path;
1455 
1456 		/* Cache the primary path address here, when we
1457 		 * need a an address for msg_name.
1458 		 */
1459 		union sctp_addr primary_addr;
1460 
1461 		/* active_path
1462 		 *   The path that we are currently using to
1463 		 *   transmit new data and most control chunks.
1464 		 */
1465 		struct sctp_transport *active_path;
1466 
1467 		/* retran_path
1468 		 *
1469 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1470 		 * ...
1471 		 * Furthermore, when its peer is multi-homed, an
1472 		 * endpoint SHOULD try to retransmit a chunk to an
1473 		 * active destination transport address that is
1474 		 * different from the last destination address to
1475 		 * which the DATA chunk was sent.
1476 		 */
1477 		struct sctp_transport *retran_path;
1478 
1479 		/* Pointer to last transport I have sent on.  */
1480 		struct sctp_transport *last_sent_to;
1481 
1482 		/* This is the last transport I have received DATA on.	*/
1483 		struct sctp_transport *last_data_from;
1484 
1485 		/*
1486 		 * Mapping  An array of bits or bytes indicating which out of
1487 		 * Array    order TSN's have been received (relative to the
1488 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1489 		 *	    order packets have been received, this array
1490 		 *	    will be set to all zero. This structure may be
1491 		 *	    in the form of a circular buffer or bit array.
1492 		 *
1493 		 * Last Rcvd   : This is the last TSN received in
1494 		 * TSN	       : sequence. This value is set initially by
1495 		 *	       : taking the peer's Initial TSN, received in
1496 		 *	       : the INIT or INIT ACK chunk, and subtracting
1497 		 *	       : one from it.
1498 		 *
1499 		 * Throughout most of the specification this is called the
1500 		 * "Cumulative TSN ACK Point".	In this case, we
1501 		 * ignore the advice in 12.2 in favour of the term
1502 		 * used in the bulk of the text.  This value is hidden
1503 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1504 		 */
1505 		struct sctp_tsnmap tsn_map;
1506 
1507 		/* This mask is used to disable sending the ASCONF chunk
1508 		 * with specified parameter to peer.
1509 		 */
1510 		__be16 addip_disabled_mask;
1511 
1512 		/* These are capabilities which our peer advertised.  */
1513 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1514 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1515 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1516 			hostname_address:1, /* Peer understands DNS addresses? */
1517 			asconf_capable:1,   /* Does peer support ADDIP? */
1518 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1519 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1520 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1521 
1522 		/* sack_needed : This flag indicates if the next received
1523 		 *             : packet is to be responded to with a
1524 		 *             : SACK. This is initialized to 0.  When a packet
1525 		 *             : is received sack_cnt is incremented. If this value
1526 		 *             : reaches 2 or more, a SACK is sent and the
1527 		 *             : value is reset to 0. Note: This is used only
1528 		 *             : when no DATA chunks are received out of
1529 		 *             : order.  When DATA chunks are out of order,
1530 		 *             : SACK's are not delayed (see Section 6).
1531 		 */
1532 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1533 			sack_generation:1,
1534 			zero_window_announced:1;
1535 		__u32	sack_cnt;
1536 
1537 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1538 
1539 		struct sctp_inithdr_host i;
1540 		void *cookie;
1541 		int cookie_len;
1542 
1543 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1544 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1545 		 * Initial TSN Value minus 1
1546 		 */
1547 		__u32 addip_serial;
1548 
1549 		/* SCTP-AUTH: We need to know pears random number, hmac list
1550 		 * and authenticated chunk list.  All that is part of the
1551 		 * cookie and these are just pointers to those locations
1552 		 */
1553 		sctp_random_param_t *peer_random;
1554 		sctp_chunks_param_t *peer_chunks;
1555 		sctp_hmac_algo_param_t *peer_hmacs;
1556 	} peer;
1557 
1558 	/* State       : A state variable indicating what state the
1559 	 *	       : association is in, i.e. COOKIE-WAIT,
1560 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1561 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1562 	 *
1563 	 *		Note: No "CLOSED" state is illustrated since if a
1564 	 *		association is "CLOSED" its TCB SHOULD be removed.
1565 	 *
1566 	 *		In this implementation we DO have a CLOSED
1567 	 *		state which is used during initiation and shutdown.
1568 	 *
1569 	 *		State takes values from SCTP_STATE_*.
1570 	 */
1571 	sctp_state_t state;
1572 
1573 	/* Overall     : The overall association error count.
1574 	 * Error Count : [Clear this any time I get something.]
1575 	 */
1576 	int overall_error_count;
1577 
1578 	/* The cookie life I award for any cookie.  */
1579 	ktime_t cookie_life;
1580 
1581 	/* These are the association's initial, max, and min RTO values.
1582 	 * These values will be initialized by system defaults, but can
1583 	 * be modified via the SCTP_RTOINFO socket option.
1584 	 */
1585 	unsigned long rto_initial;
1586 	unsigned long rto_max;
1587 	unsigned long rto_min;
1588 
1589 	/* Maximum number of new data packets that can be sent in a burst.  */
1590 	int max_burst;
1591 
1592 	/* This is the max_retrans value for the association.  This value will
1593 	 * be initialized initialized from system defaults, but can be
1594 	 * modified by the SCTP_ASSOCINFO socket option.
1595 	 */
1596 	int max_retrans;
1597 
1598 	/* This is the partially failed retrans value for the transport
1599 	 * and will be initialized from the assocs value.  This can be
1600 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1601 	 */
1602 	int pf_retrans;
1603 
1604 	/* Maximum number of times the endpoint will retransmit INIT  */
1605 	__u16 max_init_attempts;
1606 
1607 	/* How many times have we resent an INIT? */
1608 	__u16 init_retries;
1609 
1610 	/* The largest timeout or RTO value to use in attempting an INIT */
1611 	unsigned long max_init_timeo;
1612 
1613 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1614 	 * the destination address every heartbeat interval. This value
1615 	 * will be inherited by all new transports.
1616 	 */
1617 	unsigned long hbinterval;
1618 
1619 	/* This is the max_retrans value for new transports in the
1620 	 * association.
1621 	 */
1622 	__u16 pathmaxrxt;
1623 
1624 	/* Flag that path mtu update is pending */
1625 	__u8   pmtu_pending;
1626 
1627 	/* Association : The smallest PMTU discovered for all of the
1628 	 * PMTU	       : peer's transport addresses.
1629 	 */
1630 	__u32 pathmtu;
1631 
1632 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1633 	__u32 param_flags;
1634 
1635 	__u32 sackfreq;
1636 	/* SACK delay timeout */
1637 	unsigned long sackdelay;
1638 
1639 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1640 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1641 
1642 	/* Transport to which SHUTDOWN chunk was last sent.  */
1643 	struct sctp_transport *shutdown_last_sent_to;
1644 
1645 	/* Transport to which INIT chunk was last sent.  */
1646 	struct sctp_transport *init_last_sent_to;
1647 
1648 	/* How many times have we resent a SHUTDOWN */
1649 	int shutdown_retries;
1650 
1651 	/* Next TSN    : The next TSN number to be assigned to a new
1652 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1653 	 *	       : ACK chunk to the peer and incremented each
1654 	 *	       : time a DATA chunk is assigned a TSN
1655 	 *	       : (normally just prior to transmit or during
1656 	 *	       : fragmentation).
1657 	 */
1658 	__u32 next_tsn;
1659 
1660 	/*
1661 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1662 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1663 	 *	       : received in the INIT or INIT ACK chunk, and
1664 	 *	       : subtracting one from it.
1665 	 *
1666 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1667 	 */
1668 
1669 	__u32 ctsn_ack_point;
1670 
1671 	/* PR-SCTP Advanced.Peer.Ack.Point */
1672 	__u32 adv_peer_ack_point;
1673 
1674 	/* Highest TSN that is acknowledged by incoming SACKs. */
1675 	__u32 highest_sacked;
1676 
1677 	/* TSN marking the fast recovery exit point */
1678 	__u32 fast_recovery_exit;
1679 
1680 	/* Flag to track the current fast recovery state */
1681 	__u8 fast_recovery;
1682 
1683 	/* The number of unacknowledged data chunks.  Reported through
1684 	 * the SCTP_STATUS sockopt.
1685 	 */
1686 	__u16 unack_data;
1687 
1688 	/* The total number of data chunks that we've had to retransmit
1689 	 * as the result of a T3 timer expiration
1690 	 */
1691 	__u32 rtx_data_chunks;
1692 
1693 	/* This is the association's receive buffer space.  This value is used
1694 	 * to set a_rwnd field in an INIT or a SACK chunk.
1695 	 */
1696 	__u32 rwnd;
1697 
1698 	/* This is the last advertised value of rwnd over a SACK chunk. */
1699 	__u32 a_rwnd;
1700 
1701 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1702 	 * to slop over a maximum of the association's frag_point.
1703 	 */
1704 	__u32 rwnd_over;
1705 
1706 	/* Keeps treack of rwnd pressure.  This happens when we have
1707 	 * a window, but not recevie buffer (i.e small packets).  This one
1708 	 * is releases slowly (1 PMTU at a time ).
1709 	 */
1710 	__u32 rwnd_press;
1711 
1712 	/* This is the sndbuf size in use for the association.
1713 	 * This corresponds to the sndbuf size for the association,
1714 	 * as specified in the sk->sndbuf.
1715 	 */
1716 	int sndbuf_used;
1717 
1718 	/* This is the amount of memory that this association has allocated
1719 	 * in the receive path at any given time.
1720 	 */
1721 	atomic_t rmem_alloc;
1722 
1723 	/* This is the wait queue head for send requests waiting on
1724 	 * the association sndbuf space.
1725 	 */
1726 	wait_queue_head_t	wait;
1727 
1728 	/* The message size at which SCTP fragmentation will occur. */
1729 	__u32 frag_point;
1730 	__u32 user_frag;
1731 
1732 	/* Counter used to count INIT errors. */
1733 	int init_err_counter;
1734 
1735 	/* Count the number of INIT cycles (for doubling timeout). */
1736 	int init_cycle;
1737 
1738 	/* Default send parameters. */
1739 	__u16 default_stream;
1740 	__u16 default_flags;
1741 	__u32 default_ppid;
1742 	__u32 default_context;
1743 	__u32 default_timetolive;
1744 
1745 	/* Default receive parameters */
1746 	__u32 default_rcv_context;
1747 
1748 	/* Stream arrays */
1749 	struct sctp_stream *stream;
1750 
1751 	/* All outbound chunks go through this structure.  */
1752 	struct sctp_outq outqueue;
1753 
1754 	/* A smart pipe that will handle reordering and fragmentation,
1755 	 * as well as handle passing events up to the ULP.
1756 	 */
1757 	struct sctp_ulpq ulpq;
1758 
1759 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1760 	__u32 last_ecne_tsn;
1761 
1762 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1763 	__u32 last_cwr_tsn;
1764 
1765 	/* How many duplicated TSNs have we seen?  */
1766 	int numduptsns;
1767 
1768 	/* These are to support
1769 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1770 	 *  and Enforcement of Flow and Message Limits"
1771 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1772 	 * or "ADDIP" for short.
1773 	 */
1774 
1775 
1776 
1777 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1778 	 *
1779 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1780 	 * unacknowledged at any one time.  If a sender, after sending
1781 	 * an ASCONF chunk, decides it needs to transfer another
1782 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1783 	 * returns from the previous ASCONF Chunk before sending a
1784 	 * subsequent ASCONF. Note this restriction binds each side,
1785 	 * so at any time two ASCONF may be in-transit on any given
1786 	 * association (one sent from each endpoint).
1787 	 *
1788 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1789 	 * not have an ASCONF in flight, this is NULL.]
1790 	 */
1791 	struct sctp_chunk *addip_last_asconf;
1792 
1793 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1794 	 *
1795 	 * This is needed to implement itmes E1 - E4 of the updated
1796 	 * spec.  Here is the justification:
1797 	 *
1798 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1799 	 * we now need the ability to cache multiple ACKs.  The section
1800 	 * describes in detail how they are cached and cleaned up.
1801 	 */
1802 	struct list_head asconf_ack_list;
1803 
1804 	/* These ASCONF chunks are waiting to be sent.
1805 	 *
1806 	 * These chunaks can't be pushed to outqueue until receiving
1807 	 * ASCONF_ACK for the previous ASCONF indicated by
1808 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1809 	 * is in flight at any time.
1810 	 *
1811 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1812 	 *
1813 	 * In defining the ASCONF Chunk transfer procedures, it is
1814 	 * essential that these transfers MUST NOT cause congestion
1815 	 * within the network.	To achieve this, we place these
1816 	 * restrictions on the transfer of ASCONF Chunks:
1817 	 *
1818 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1819 	 * unacknowledged at any one time.  If a sender, after sending
1820 	 * an ASCONF chunk, decides it needs to transfer another
1821 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1822 	 * returns from the previous ASCONF Chunk before sending a
1823 	 * subsequent ASCONF. Note this restriction binds each side,
1824 	 * so at any time two ASCONF may be in-transit on any given
1825 	 * association (one sent from each endpoint).
1826 	 *
1827 	 *
1828 	 * [I really think this is EXACTLY the sort of intelligence
1829 	 *  which already resides in sctp_outq.	 Please move this
1830 	 *  queue and its supporting logic down there.	--piggy]
1831 	 */
1832 	struct list_head addip_chunk_list;
1833 
1834 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1835 	 *
1836 	 * A2) A serial number should be assigned to the Chunk. The
1837 	 * serial number SHOULD be a monotonically increasing
1838 	 * number. The serial number SHOULD be initialized at
1839 	 * the start of the association to the same value as the
1840 	 * Initial TSN and every time a new ASCONF chunk is created
1841 	 * it is incremented by one after assigning the serial number
1842 	 * to the newly created chunk.
1843 	 *
1844 	 * ADDIP
1845 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1846 	 *
1847 	 * Serial Number : 32 bits (unsigned integer)
1848 	 *
1849 	 * This value represents a Serial Number for the ASCONF
1850 	 * Chunk. The valid range of Serial Number is from 0 to
1851 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1852 	 * after reaching 4294967295.
1853 	 */
1854 	__u32 addip_serial;
1855 	int src_out_of_asoc_ok;
1856 	union sctp_addr *asconf_addr_del_pending;
1857 	struct sctp_transport *new_transport;
1858 
1859 	/* SCTP AUTH: list of the endpoint shared keys.  These
1860 	 * keys are provided out of band by the user applicaton
1861 	 * and can't change during the lifetime of the association
1862 	 */
1863 	struct list_head endpoint_shared_keys;
1864 
1865 	/* SCTP AUTH:
1866 	 * The current generated assocaition shared key (secret)
1867 	 */
1868 	struct sctp_auth_bytes *asoc_shared_key;
1869 
1870 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1871 	 * that we support.
1872 	 */
1873 	__u16 default_hmac_id;
1874 
1875 	__u16 active_key_id;
1876 
1877 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
1878 	     temp:1,		/* Is it a temporary association? */
1879 	     prsctp_enable:1,
1880 	     reconf_enable:1;
1881 
1882 	__u8 strreset_enable;
1883 	__u8 strreset_outstanding; /* request param count on the fly */
1884 
1885 	__u32 strreset_outseq; /* Update after receiving response */
1886 	__u32 strreset_inseq; /* Update after receiving request */
1887 
1888 	struct sctp_chunk *strreset_chunk; /* save request chunk */
1889 
1890 	struct sctp_priv_assoc_stats stats;
1891 
1892 	int sent_cnt_removable;
1893 
1894 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1895 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1896 };
1897 
1898 
1899 /* An eyecatcher for determining if we are really looking at an
1900  * association data structure.
1901  */
1902 enum {
1903 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1904 };
1905 
1906 /* Recover the outter association structure. */
1907 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1908 {
1909 	struct sctp_association *asoc;
1910 
1911 	asoc = container_of(base, struct sctp_association, base);
1912 	return asoc;
1913 }
1914 
1915 /* These are function signatures for manipulating associations.	 */
1916 
1917 
1918 struct sctp_association *
1919 sctp_association_new(const struct sctp_endpoint *, const struct sock *,
1920 		     sctp_scope_t scope, gfp_t gfp);
1921 void sctp_association_free(struct sctp_association *);
1922 void sctp_association_put(struct sctp_association *);
1923 void sctp_association_hold(struct sctp_association *);
1924 
1925 struct sctp_transport *sctp_assoc_choose_alter_transport(
1926 	struct sctp_association *, struct sctp_transport *);
1927 void sctp_assoc_update_retran_path(struct sctp_association *);
1928 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1929 					  const union sctp_addr *);
1930 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1931 			    const union sctp_addr *laddr);
1932 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
1933 				     const union sctp_addr *address,
1934 				     const gfp_t gfp,
1935 				     const int peer_state);
1936 void sctp_assoc_del_peer(struct sctp_association *asoc,
1937 			 const union sctp_addr *addr);
1938 void sctp_assoc_rm_peer(struct sctp_association *asoc,
1939 			 struct sctp_transport *peer);
1940 void sctp_assoc_control_transport(struct sctp_association *,
1941 				  struct sctp_transport *,
1942 				  sctp_transport_cmd_t, sctp_sn_error_t);
1943 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
1944 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
1945 					   struct net *,
1946 					   const union sctp_addr *,
1947 					   const union sctp_addr *);
1948 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
1949 void sctp_assoc_update(struct sctp_association *old,
1950 		       struct sctp_association *new);
1951 
1952 __u32 sctp_association_get_next_tsn(struct sctp_association *);
1953 
1954 void sctp_assoc_sync_pmtu(struct sock *, struct sctp_association *);
1955 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
1956 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
1957 void sctp_assoc_set_primary(struct sctp_association *,
1958 			    struct sctp_transport *);
1959 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
1960 				    struct sctp_transport *);
1961 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
1962 				     sctp_scope_t, gfp_t);
1963 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
1964 					 struct sctp_cookie*,
1965 					 gfp_t gfp);
1966 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
1967 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
1968 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
1969 					const struct sctp_association *asoc,
1970 					__be32 serial);
1971 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
1972 
1973 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
1974 			const union sctp_addr *ss2);
1975 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
1976 
1977 /* A convenience structure to parse out SCTP specific CMSGs. */
1978 typedef struct sctp_cmsgs {
1979 	struct sctp_initmsg *init;
1980 	struct sctp_sndrcvinfo *srinfo;
1981 	struct sctp_sndinfo *sinfo;
1982 } sctp_cmsgs_t;
1983 
1984 /* Structure for tracking memory objects */
1985 typedef struct {
1986 	char *label;
1987 	atomic_t *counter;
1988 } sctp_dbg_objcnt_entry_t;
1989 
1990 #endif /* __sctp_structs_h__ */
1991