xref: /openbmc/linux/include/net/sctp/structs.h (revision 4a3fad70)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * This SCTP implementation is free software;
10  * you can redistribute it and/or modify it under the terms of
11  * the GNU General Public License as published by
12  * the Free Software Foundation; either version 2, or (at your option)
13  * any later version.
14  *
15  * This SCTP implementation is distributed in the hope that it
16  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17  *		   ************************
18  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19  * See the GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with GNU CC; see the file COPYING.  If not, see
23  * <http://www.gnu.org/licenses/>.
24  *
25  * Please send any bug reports or fixes you make to the
26  * email addresses:
27  *    lksctp developers <linux-sctp@vger.kernel.org>
28  *
29  * Written or modified by:
30  *    Randall Stewart	    <randall@sctp.chicago.il.us>
31  *    Ken Morneau	    <kmorneau@cisco.com>
32  *    Qiaobing Xie	    <qxie1@email.mot.com>
33  *    La Monte H.P. Yarroll <piggy@acm.org>
34  *    Karl Knutson	    <karl@athena.chicago.il.us>
35  *    Jon Grimm		    <jgrimm@us.ibm.com>
36  *    Xingang Guo	    <xingang.guo@intel.com>
37  *    Hui Huang		    <hui.huang@nokia.com>
38  *    Sridhar Samudrala	    <sri@us.ibm.com>
39  *    Daisy Chang	    <daisyc@us.ibm.com>
40  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
41  *    Ardelle Fan	    <ardelle.fan@intel.com>
42  *    Ryan Layer	    <rmlayer@us.ibm.com>
43  *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
44  *    Kevin Gao             <kevin.gao@intel.com>
45  */
46 
47 #ifndef __sctp_structs_h__
48 #define __sctp_structs_h__
49 
50 #include <linux/ktime.h>
51 #include <linux/rhashtable.h>
52 #include <linux/socket.h>	/* linux/in.h needs this!!    */
53 #include <linux/in.h>		/* We get struct sockaddr_in. */
54 #include <linux/in6.h>		/* We get struct in6_addr     */
55 #include <linux/ipv6.h>
56 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
57 #include <linux/atomic.h>		/* This gets us atomic counters.  */
58 #include <linux/skbuff.h>	/* We need sk_buff_head. */
59 #include <linux/workqueue.h>	/* We need tq_struct.	 */
60 #include <linux/sctp.h>		/* We need sctp* header structs.  */
61 #include <net/sctp/auth.h>	/* We need auth specific structs */
62 #include <net/ip.h>		/* For inet_skb_parm */
63 
64 /* A convenience structure for handling sockaddr structures.
65  * We should wean ourselves off this.
66  */
67 union sctp_addr {
68 	struct sockaddr_in v4;
69 	struct sockaddr_in6 v6;
70 	struct sockaddr sa;
71 };
72 
73 /* Forward declarations for data structures. */
74 struct sctp_globals;
75 struct sctp_endpoint;
76 struct sctp_association;
77 struct sctp_transport;
78 struct sctp_packet;
79 struct sctp_chunk;
80 struct sctp_inq;
81 struct sctp_outq;
82 struct sctp_bind_addr;
83 struct sctp_ulpq;
84 struct sctp_ep_common;
85 struct crypto_shash;
86 struct sctp_stream;
87 
88 
89 #include <net/sctp/tsnmap.h>
90 #include <net/sctp/ulpevent.h>
91 #include <net/sctp/ulpqueue.h>
92 
93 /* Structures useful for managing bind/connect. */
94 
95 struct sctp_bind_bucket {
96 	unsigned short	port;
97 	unsigned short	fastreuse;
98 	struct hlist_node	node;
99 	struct hlist_head	owner;
100 	struct net	*net;
101 };
102 
103 struct sctp_bind_hashbucket {
104 	spinlock_t	lock;
105 	struct hlist_head	chain;
106 };
107 
108 /* Used for hashing all associations.  */
109 struct sctp_hashbucket {
110 	rwlock_t	lock;
111 	struct hlist_head	chain;
112 } __attribute__((__aligned__(8)));
113 
114 
115 /* The SCTP globals structure. */
116 extern struct sctp_globals {
117 	/* This is a list of groups of functions for each address
118 	 * family that we support.
119 	 */
120 	struct list_head address_families;
121 
122 	/* This is the hash of all endpoints. */
123 	struct sctp_hashbucket *ep_hashtable;
124 	/* This is the sctp port control hash.	*/
125 	struct sctp_bind_hashbucket *port_hashtable;
126 	/* This is the hash of all transports. */
127 	struct rhltable transport_hashtable;
128 
129 	/* Sizes of above hashtables. */
130 	int ep_hashsize;
131 	int port_hashsize;
132 
133 	/* Default initialization values to be applied to new associations. */
134 	__u16 max_instreams;
135 	__u16 max_outstreams;
136 
137 	/* Flag to indicate whether computing and verifying checksum
138 	 * is disabled. */
139         bool checksum_disable;
140 } sctp_globals;
141 
142 #define sctp_max_instreams		(sctp_globals.max_instreams)
143 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
144 #define sctp_address_families		(sctp_globals.address_families)
145 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
146 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
147 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
148 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
149 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
150 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
151 
152 /* SCTP Socket type: UDP or TCP style. */
153 enum sctp_socket_type {
154 	SCTP_SOCKET_UDP = 0,
155 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
156 	SCTP_SOCKET_TCP
157 };
158 
159 /* Per socket SCTP information. */
160 struct sctp_sock {
161 	/* inet_sock has to be the first member of sctp_sock */
162 	struct inet_sock inet;
163 	/* What kind of a socket is this? */
164 	enum sctp_socket_type type;
165 
166 	/* PF_ family specific functions.  */
167 	struct sctp_pf *pf;
168 
169 	/* Access to HMAC transform. */
170 	struct crypto_shash *hmac;
171 	char *sctp_hmac_alg;
172 
173 	/* What is our base endpointer? */
174 	struct sctp_endpoint *ep;
175 
176 	struct sctp_bind_bucket *bind_hash;
177 	/* Various Socket Options.  */
178 	__u16 default_stream;
179 	__u32 default_ppid;
180 	__u16 default_flags;
181 	__u32 default_context;
182 	__u32 default_timetolive;
183 	__u32 default_rcv_context;
184 	int max_burst;
185 
186 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
187 	 * the destination address every heartbeat interval. This value
188 	 * will be inherited by all new associations.
189 	 */
190 	__u32 hbinterval;
191 
192 	/* This is the max_retrans value for new associations. */
193 	__u16 pathmaxrxt;
194 
195 	/* The initial Path MTU to use for new associations. */
196 	__u32 pathmtu;
197 
198 	/* The default SACK delay timeout for new associations. */
199 	__u32 sackdelay;
200 	__u32 sackfreq;
201 
202 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
203 	__u32 param_flags;
204 
205 	struct sctp_initmsg initmsg;
206 	struct sctp_rtoinfo rtoinfo;
207 	struct sctp_paddrparams paddrparam;
208 	struct sctp_event_subscribe subscribe;
209 	struct sctp_assocparams assocparams;
210 
211 	int user_frag;
212 
213 	__u32 autoclose;
214 	__u32 adaptation_ind;
215 	__u32 pd_point;
216 	__u16	nodelay:1,
217 		disable_fragments:1,
218 		v4mapped:1,
219 		frag_interleave:1,
220 		recvrcvinfo:1,
221 		recvnxtinfo:1,
222 		data_ready_signalled:1;
223 
224 	atomic_t pd_mode;
225 	/* Receive to here while partial delivery is in effect. */
226 	struct sk_buff_head pd_lobby;
227 
228 	/* These must be the last fields, as they will skipped on copies,
229 	 * like on accept and peeloff operations
230 	 */
231 	struct list_head auto_asconf_list;
232 	int do_auto_asconf;
233 };
234 
235 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
236 {
237        return (struct sctp_sock *)sk;
238 }
239 
240 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
241 {
242        return (struct sock *)sp;
243 }
244 
245 #if IS_ENABLED(CONFIG_IPV6)
246 struct sctp6_sock {
247        struct sctp_sock  sctp;
248        struct ipv6_pinfo inet6;
249 };
250 #endif /* CONFIG_IPV6 */
251 
252 
253 /* This is our APPLICATION-SPECIFIC state cookie.
254  * THIS IS NOT DICTATED BY THE SPECIFICATION.
255  */
256 /* These are the parts of an association which we send in the cookie.
257  * Most of these are straight out of:
258  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
259  *
260  */
261 
262 struct sctp_cookie {
263 
264 	/* My	       : Tag expected in every inbound packet and sent
265 	 * Verification: in the INIT or INIT ACK chunk.
266 	 * Tag	       :
267 	 */
268 	__u32 my_vtag;
269 
270 	/* Peer's      : Tag expected in every outbound packet except
271 	 * Verification: in the INIT chunk.
272 	 * Tag	       :
273 	 */
274 	__u32 peer_vtag;
275 
276 	/* The rest of these are not from the spec, but really need to
277 	 * be in the cookie.
278 	 */
279 
280 	/* My Tie Tag  : Assist in discovering a restarting association. */
281 	__u32 my_ttag;
282 
283 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
284 	__u32 peer_ttag;
285 
286 	/* When does this cookie expire? */
287 	ktime_t expiration;
288 
289 	/* Number of inbound/outbound streams which are set
290 	 * and negotiated during the INIT process.
291 	 */
292 	__u16 sinit_num_ostreams;
293 	__u16 sinit_max_instreams;
294 
295 	/* This is the first sequence number I used.  */
296 	__u32 initial_tsn;
297 
298 	/* This holds the originating address of the INIT packet.  */
299 	union sctp_addr peer_addr;
300 
301 	/* IG Section 2.35.3
302 	 * Include the source port of the INIT-ACK
303 	 */
304 	__u16		my_port;
305 
306 	__u8 prsctp_capable;
307 
308 	/* Padding for future use */
309 	__u8 padding;
310 
311 	__u32 adaptation_ind;
312 
313 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
314 			 SCTP_AUTH_RANDOM_LENGTH];
315 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
316 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
317 
318 	/* This is a shim for my peer's INIT packet, followed by
319 	 * a copy of the raw address list of the association.
320 	 * The length of the raw address list is saved in the
321 	 * raw_addr_list_len field, which will be used at the time when
322 	 * the association TCB is re-constructed from the cookie.
323 	 */
324 	__u32 raw_addr_list_len;
325 	struct sctp_init_chunk peer_init[0];
326 };
327 
328 
329 /* The format of our cookie that we send to our peer. */
330 struct sctp_signed_cookie {
331 	__u8 signature[SCTP_SECRET_SIZE];
332 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
333 	struct sctp_cookie c;
334 } __packed;
335 
336 /* This is another convenience type to allocate memory for address
337  * params for the maximum size and pass such structures around
338  * internally.
339  */
340 union sctp_addr_param {
341 	struct sctp_paramhdr p;
342 	struct sctp_ipv4addr_param v4;
343 	struct sctp_ipv6addr_param v6;
344 };
345 
346 /* A convenience type to allow walking through the various
347  * parameters and avoid casting all over the place.
348  */
349 union sctp_params {
350 	void *v;
351 	struct sctp_paramhdr *p;
352 	struct sctp_cookie_preserve_param *life;
353 	struct sctp_hostname_param *dns;
354 	struct sctp_cookie_param *cookie;
355 	struct sctp_supported_addrs_param *sat;
356 	struct sctp_ipv4addr_param *v4;
357 	struct sctp_ipv6addr_param *v6;
358 	union sctp_addr_param *addr;
359 	struct sctp_adaptation_ind_param *aind;
360 	struct sctp_supported_ext_param *ext;
361 	struct sctp_random_param *random;
362 	struct sctp_chunks_param *chunks;
363 	struct sctp_hmac_algo_param *hmac_algo;
364 	struct sctp_addip_param *addip;
365 };
366 
367 /* RFC 2960.  Section 3.3.5 Heartbeat.
368  *    Heartbeat Information: variable length
369  *    The Sender-specific Heartbeat Info field should normally include
370  *    information about the sender's current time when this HEARTBEAT
371  *    chunk is sent and the destination transport address to which this
372  *    HEARTBEAT is sent (see Section 8.3).
373  */
374 struct sctp_sender_hb_info {
375 	struct sctp_paramhdr param_hdr;
376 	union sctp_addr daddr;
377 	unsigned long sent_at;
378 	__u64 hb_nonce;
379 };
380 
381 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
382 		     gfp_t gfp);
383 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
384 void sctp_stream_free(struct sctp_stream *stream);
385 void sctp_stream_clear(struct sctp_stream *stream);
386 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
387 
388 /* What is the current SSN number for this stream? */
389 #define sctp_ssn_peek(stream, type, sid) \
390 	((stream)->type[sid].ssn)
391 
392 /* Return the next SSN number for this stream.	*/
393 #define sctp_ssn_next(stream, type, sid) \
394 	((stream)->type[sid].ssn++)
395 
396 /* Skip over this ssn and all below. */
397 #define sctp_ssn_skip(stream, type, sid, ssn) \
398 	((stream)->type[sid].ssn = ssn + 1)
399 
400 /*
401  * Pointers to address related SCTP functions.
402  * (i.e. things that depend on the address family.)
403  */
404 struct sctp_af {
405 	int		(*sctp_xmit)	(struct sk_buff *skb,
406 					 struct sctp_transport *);
407 	int		(*setsockopt)	(struct sock *sk,
408 					 int level,
409 					 int optname,
410 					 char __user *optval,
411 					 unsigned int optlen);
412 	int		(*getsockopt)	(struct sock *sk,
413 					 int level,
414 					 int optname,
415 					 char __user *optval,
416 					 int __user *optlen);
417 	int		(*compat_setsockopt)	(struct sock *sk,
418 					 int level,
419 					 int optname,
420 					 char __user *optval,
421 					 unsigned int optlen);
422 	int		(*compat_getsockopt)	(struct sock *sk,
423 					 int level,
424 					 int optname,
425 					 char __user *optval,
426 					 int __user *optlen);
427 	void		(*get_dst)	(struct sctp_transport *t,
428 					 union sctp_addr *saddr,
429 					 struct flowi *fl,
430 					 struct sock *sk);
431 	void		(*get_saddr)	(struct sctp_sock *sk,
432 					 struct sctp_transport *t,
433 					 struct flowi *fl);
434 	void		(*copy_addrlist) (struct list_head *,
435 					  struct net_device *);
436 	int		(*cmp_addr)	(const union sctp_addr *addr1,
437 					 const union sctp_addr *addr2);
438 	void		(*addr_copy)	(union sctp_addr *dst,
439 					 union sctp_addr *src);
440 	void		(*from_skb)	(union sctp_addr *,
441 					 struct sk_buff *skb,
442 					 int saddr);
443 	void		(*from_sk)	(union sctp_addr *,
444 					 struct sock *sk);
445 	void		(*from_addr_param) (union sctp_addr *,
446 					    union sctp_addr_param *,
447 					    __be16 port, int iif);
448 	int		(*to_addr_param) (const union sctp_addr *,
449 					  union sctp_addr_param *);
450 	int		(*addr_valid)	(union sctp_addr *,
451 					 struct sctp_sock *,
452 					 const struct sk_buff *);
453 	enum sctp_scope	(*scope)(union sctp_addr *);
454 	void		(*inaddr_any)	(union sctp_addr *, __be16);
455 	int		(*is_any)	(const union sctp_addr *);
456 	int		(*available)	(union sctp_addr *,
457 					 struct sctp_sock *);
458 	int		(*skb_iif)	(const struct sk_buff *sk);
459 	int		(*is_ce)	(const struct sk_buff *sk);
460 	void		(*seq_dump_addr)(struct seq_file *seq,
461 					 union sctp_addr *addr);
462 	void		(*ecn_capable)(struct sock *sk);
463 	__u16		net_header_len;
464 	int		sockaddr_len;
465 	sa_family_t	sa_family;
466 	struct list_head list;
467 };
468 
469 struct sctp_af *sctp_get_af_specific(sa_family_t);
470 int sctp_register_af(struct sctp_af *);
471 
472 /* Protocol family functions. */
473 struct sctp_pf {
474 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
475 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
476 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
477 	int  (*cmp_addr) (const union sctp_addr *,
478 			  const union sctp_addr *,
479 			  struct sctp_sock *);
480 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
481 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
482 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
483 	struct sock *(*create_accept_sk) (struct sock *sk,
484 					  struct sctp_association *asoc,
485 					  bool kern);
486 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
487 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
488 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
489 	struct sctp_af *af;
490 };
491 
492 
493 /* Structure to track chunk fragments that have been acked, but peer
494  * fragments of the same message have not.
495  */
496 struct sctp_datamsg {
497 	/* Chunks waiting to be submitted to lower layer. */
498 	struct list_head chunks;
499 	/* Reference counting. */
500 	refcount_t refcnt;
501 	/* When is this message no longer interesting to the peer? */
502 	unsigned long expires_at;
503 	/* Did the messenge fail to send? */
504 	int send_error;
505 	u8 send_failed:1,
506 	   can_delay:1,	/* should this message be Nagle delayed */
507 	   abandoned:1;	/* should this message be abandoned */
508 };
509 
510 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
511 					    struct sctp_sndrcvinfo *,
512 					    struct iov_iter *);
513 void sctp_datamsg_free(struct sctp_datamsg *);
514 void sctp_datamsg_put(struct sctp_datamsg *);
515 void sctp_chunk_fail(struct sctp_chunk *, int error);
516 int sctp_chunk_abandoned(struct sctp_chunk *);
517 
518 /* RFC2960 1.4 Key Terms
519  *
520  * o Chunk: A unit of information within an SCTP packet, consisting of
521  * a chunk header and chunk-specific content.
522  *
523  * As a matter of convenience, we remember the SCTP common header for
524  * each chunk as well as a few other header pointers...
525  */
526 struct sctp_chunk {
527 	struct list_head list;
528 
529 	refcount_t refcnt;
530 
531 	/* How many times this chunk have been sent, for prsctp RTX policy */
532 	int sent_count;
533 
534 	union {
535 		/* This is our link to the per-transport transmitted list.  */
536 		struct list_head transmitted_list;
537 		/* List in specific stream outq */
538 		struct list_head stream_list;
539 	};
540 
541 	/* This field is used by chunks that hold fragmented data.
542 	 * For the first fragment this is the list that holds the rest of
543 	 * fragments. For the remaining fragments, this is the link to the
544 	 * frag_list maintained in the first fragment.
545 	 */
546 	struct list_head frag_list;
547 
548 	/* This points to the sk_buff containing the actual data.  */
549 	struct sk_buff *skb;
550 
551 	/* In case of GSO packets, this will store the head one */
552 	struct sk_buff *head_skb;
553 
554 	/* These are the SCTP headers by reverse order in a packet.
555 	 * Note that some of these may happen more than once.  In that
556 	 * case, we point at the "current" one, whatever that means
557 	 * for that level of header.
558 	 */
559 
560 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
561 	union sctp_params param_hdr;
562 	union {
563 		__u8 *v;
564 		struct sctp_datahdr *data_hdr;
565 		struct sctp_inithdr *init_hdr;
566 		struct sctp_sackhdr *sack_hdr;
567 		struct sctp_heartbeathdr *hb_hdr;
568 		struct sctp_sender_hb_info *hbs_hdr;
569 		struct sctp_shutdownhdr *shutdown_hdr;
570 		struct sctp_signed_cookie *cookie_hdr;
571 		struct sctp_ecnehdr *ecne_hdr;
572 		struct sctp_cwrhdr *ecn_cwr_hdr;
573 		struct sctp_errhdr *err_hdr;
574 		struct sctp_addiphdr *addip_hdr;
575 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
576 		struct sctp_authhdr *auth_hdr;
577 	} subh;
578 
579 	__u8 *chunk_end;
580 
581 	struct sctp_chunkhdr *chunk_hdr;
582 	struct sctphdr *sctp_hdr;
583 
584 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
585 	struct sctp_sndrcvinfo sinfo;
586 
587 	/* Which association does this belong to?  */
588 	struct sctp_association *asoc;
589 
590 	/* What endpoint received this chunk? */
591 	struct sctp_ep_common *rcvr;
592 
593 	/* We fill this in if we are calculating RTT. */
594 	unsigned long sent_at;
595 
596 	/* What is the origin IP address for this chunk?  */
597 	union sctp_addr source;
598 	/* Destination address for this chunk. */
599 	union sctp_addr dest;
600 
601 	/* For outbound message, track all fragments for SEND_FAILED. */
602 	struct sctp_datamsg *msg;
603 
604 	/* For an inbound chunk, this tells us where it came from.
605 	 * For an outbound chunk, it tells us where we'd like it to
606 	 * go.	It is NULL if we have no preference.
607 	 */
608 	struct sctp_transport *transport;
609 
610 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
611 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
612 	 * spec violates the principle premis that all chunks are processed
613 	 * in order.
614 	 */
615 	struct sk_buff *auth_chunk;
616 
617 #define SCTP_CAN_FRTX 0x0
618 #define SCTP_NEED_FRTX 0x1
619 #define SCTP_DONT_FRTX 0x2
620 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
621 		has_tsn:1,		/* Does this chunk have a TSN yet? */
622 		has_ssn:1,		/* Does this chunk have a SSN yet? */
623 		singleton:1,		/* Only chunk in the packet? */
624 		end_of_packet:1,	/* Last chunk in the packet? */
625 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
626 		pdiscard:1,		/* Discard the whole packet now? */
627 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
628 		data_accepted:1,	/* At least 1 chunk accepted */
629 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
630 		has_asconf:1,		/* IN: have seen an asconf before */
631 		tsn_missing_report:2,	/* Data chunk missing counter. */
632 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
633 };
634 
635 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
636 void sctp_chunk_hold(struct sctp_chunk *);
637 void sctp_chunk_put(struct sctp_chunk *);
638 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
639 			  struct iov_iter *from);
640 void sctp_chunk_free(struct sctp_chunk *);
641 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
642 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
643 				 const struct sctp_association *,
644 				 struct sock *, gfp_t gfp);
645 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
646 		     union sctp_addr *);
647 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
648 
649 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
650 {
651 	return ntohs(ch->subh.data_hdr->stream);
652 }
653 
654 enum {
655 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
656 	SCTP_ADDR_SRC,		/* address can be used as source */
657 	SCTP_ADDR_DEL,		/* address about to be deleted */
658 };
659 
660 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
661 struct sctp_sockaddr_entry {
662 	struct list_head list;
663 	struct rcu_head	rcu;
664 	union sctp_addr a;
665 	__u8 state;
666 	__u8 valid;
667 };
668 
669 #define SCTP_ADDRESS_TICK_DELAY	500
670 
671 /* This structure holds lists of chunks as we are assembling for
672  * transmission.
673  */
674 struct sctp_packet {
675 	/* These are the SCTP header values (host order) for the packet. */
676 	__u16 source_port;
677 	__u16 destination_port;
678 	__u32 vtag;
679 
680 	/* This contains the payload chunks.  */
681 	struct list_head chunk_list;
682 
683 	/* This is the overhead of the sctp and ip headers. */
684 	size_t overhead;
685 	/* This is the total size of all chunks INCLUDING padding.  */
686 	size_t size;
687 	/* This is the maximum size this packet may have */
688 	size_t max_size;
689 
690 	/* The packet is destined for this transport address.
691 	 * The function we finally use to pass down to the next lower
692 	 * layer lives in the transport structure.
693 	 */
694 	struct sctp_transport *transport;
695 
696 	/* pointer to the auth chunk for this packet */
697 	struct sctp_chunk *auth;
698 
699 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
700 	    has_sack:1,		/* This packet contains a SACK chunk. */
701 	    has_auth:1,		/* This packet contains an AUTH chunk */
702 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
703 	    ipfragok:1;		/* So let ip fragment this packet */
704 };
705 
706 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
707 		      __u16 sport, __u16 dport);
708 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
709 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
710 					  struct sctp_chunk *chunk,
711 					  int one_packet, gfp_t gfp);
712 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
713 					struct sctp_chunk *chunk);
714 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
715 void sctp_packet_free(struct sctp_packet *);
716 
717 static inline int sctp_packet_empty(struct sctp_packet *packet)
718 {
719 	return packet->size == packet->overhead;
720 }
721 
722 /* This represents a remote transport address.
723  * For local transport addresses, we just use union sctp_addr.
724  *
725  * RFC2960 Section 1.4 Key Terms
726  *
727  *   o	Transport address:  A Transport Address is traditionally defined
728  *	by Network Layer address, Transport Layer protocol and Transport
729  *	Layer port number.  In the case of SCTP running over IP, a
730  *	transport address is defined by the combination of an IP address
731  *	and an SCTP port number (where SCTP is the Transport protocol).
732  *
733  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
734  *
735  *   o	The sender keeps a separate congestion control parameter set for
736  *	each of the destination addresses it can send to (not each
737  *	source-destination pair but for each destination).  The parameters
738  *	should decay if the address is not used for a long enough time
739  *	period.
740  *
741  */
742 struct sctp_transport {
743 	/* A list of transports. */
744 	struct list_head transports;
745 	struct rhlist_head node;
746 
747 	/* Reference counting. */
748 	refcount_t refcnt;
749 		/* RTO-Pending : A flag used to track if one of the DATA
750 		 *		chunks sent to this address is currently being
751 		 *		used to compute a RTT. If this flag is 0,
752 		 *		the next DATA chunk sent to this destination
753 		 *		should be used to compute a RTT and this flag
754 		 *		should be set. Every time the RTT
755 		 *		calculation completes (i.e. the DATA chunk
756 		 *		is SACK'd) clear this flag.
757 		 */
758 	__u32	rto_pending:1,
759 
760 		/*
761 		 * hb_sent : a flag that signals that we have a pending
762 		 * heartbeat.
763 		 */
764 		hb_sent:1,
765 
766 		/* Is the Path MTU update pending on this tranport */
767 		pmtu_pending:1,
768 
769 		dst_pending_confirm:1,	/* need to confirm neighbour */
770 
771 		/* Has this transport moved the ctsn since we last sacked */
772 		sack_generation:1;
773 	u32 dst_cookie;
774 
775 	struct flowi fl;
776 
777 	/* This is the peer's IP address and port. */
778 	union sctp_addr ipaddr;
779 
780 	/* These are the functions we call to handle LLP stuff.	 */
781 	struct sctp_af *af_specific;
782 
783 	/* Which association do we belong to?  */
784 	struct sctp_association *asoc;
785 
786 	/* RFC2960
787 	 *
788 	 * 12.3 Per Transport Address Data
789 	 *
790 	 * For each destination transport address in the peer's
791 	 * address list derived from the INIT or INIT ACK chunk, a
792 	 * number of data elements needs to be maintained including:
793 	 */
794 	/* RTO	       : The current retransmission timeout value.  */
795 	unsigned long rto;
796 
797 	__u32 rtt;		/* This is the most recent RTT.	 */
798 
799 	/* RTTVAR      : The current RTT variation.  */
800 	__u32 rttvar;
801 
802 	/* SRTT	       : The current smoothed round trip time.	*/
803 	__u32 srtt;
804 
805 	/*
806 	 * These are the congestion stats.
807 	 */
808 	/* cwnd	       : The current congestion window.	 */
809 	__u32 cwnd;		  /* This is the actual cwnd.  */
810 
811 	/* ssthresh    : The current slow start threshold value.  */
812 	__u32 ssthresh;
813 
814 	/* partial     : The tracking method for increase of cwnd when in
815 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
816 	 */
817 	__u32 partial_bytes_acked;
818 
819 	/* Data that has been sent, but not acknowledged. */
820 	__u32 flight_size;
821 
822 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
823 
824 	/* Destination */
825 	struct dst_entry *dst;
826 	/* Source address. */
827 	union sctp_addr saddr;
828 
829 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
830 	 * the destination address every heartbeat interval.
831 	 */
832 	unsigned long hbinterval;
833 
834 	/* SACK delay timeout */
835 	unsigned long sackdelay;
836 	__u32 sackfreq;
837 
838 	/* When was the last time that we heard from this transport? We use
839 	 * this to pick new active and retran paths.
840 	 */
841 	ktime_t last_time_heard;
842 
843 	/* When was the last time that we sent a chunk using this
844 	 * transport? We use this to check for idle transports
845 	 */
846 	unsigned long last_time_sent;
847 
848 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
849 	 * indication based on ECNE chunk.
850 	 */
851 	unsigned long last_time_ecne_reduced;
852 
853 	/* This is the max_retrans value for the transport and will
854 	 * be initialized from the assocs value.  This can be changed
855 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
856 	 */
857 	__u16 pathmaxrxt;
858 
859 	/* This is the partially failed retrans value for the transport
860 	 * and will be initialized from the assocs value.  This can be changed
861 	 * using the SCTP_PEER_ADDR_THLDS socket option
862 	 */
863 	int pf_retrans;
864 	/* PMTU	      : The current known path MTU.  */
865 	__u32 pathmtu;
866 
867 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
868 	__u32 param_flags;
869 
870 	/* The number of times INIT has been sent on this transport. */
871 	int init_sent_count;
872 
873 	/* state       : The current state of this destination,
874 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
875 	 */
876 	int state;
877 
878 	/* These are the error stats for this destination.  */
879 
880 	/* Error count : The current error count for this destination.	*/
881 	unsigned short error_count;
882 
883 	/* Per	       : A timer used by each destination.
884 	 * Destination :
885 	 * Timer       :
886 	 *
887 	 * [Everywhere else in the text this is called T3-rtx. -ed]
888 	 */
889 	struct timer_list T3_rtx_timer;
890 
891 	/* Heartbeat timer is per destination. */
892 	struct timer_list hb_timer;
893 
894 	/* Timer to handle ICMP proto unreachable envets */
895 	struct timer_list proto_unreach_timer;
896 
897 	/* Timer to handler reconf chunk rtx */
898 	struct timer_list reconf_timer;
899 
900 	/* Since we're using per-destination retransmission timers
901 	 * (see above), we're also using per-destination "transmitted"
902 	 * queues.  This probably ought to be a private struct
903 	 * accessible only within the outqueue, but it's not, yet.
904 	 */
905 	struct list_head transmitted;
906 
907 	/* We build bundle-able packets for this transport here.  */
908 	struct sctp_packet packet;
909 
910 	/* This is the list of transports that have chunks to send.  */
911 	struct list_head send_ready;
912 
913 	/* State information saved for SFR_CACC algorithm. The key
914 	 * idea in SFR_CACC is to maintain state at the sender on a
915 	 * per-destination basis when a changeover happens.
916 	 *	char changeover_active;
917 	 *	char cycling_changeover;
918 	 *	__u32 next_tsn_at_change;
919 	 *	char cacc_saw_newack;
920 	 */
921 	struct {
922 		/* An unsigned integer, which stores the next TSN to be
923 		 * used by the sender, at the moment of changeover.
924 		 */
925 		__u32 next_tsn_at_change;
926 
927 		/* A flag which indicates the occurrence of a changeover */
928 		char changeover_active;
929 
930 		/* A flag which indicates whether the change of primary is
931 		 * the first switch to this destination address during an
932 		 * active switch.
933 		 */
934 		char cycling_changeover;
935 
936 		/* A temporary flag, which is used during the processing of
937 		 * a SACK to estimate the causative TSN(s)'s group.
938 		 */
939 		char cacc_saw_newack;
940 	} cacc;
941 
942 	/* 64-bit random number sent with heartbeat. */
943 	__u64 hb_nonce;
944 
945 	struct rcu_head rcu;
946 };
947 
948 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
949 					  gfp_t);
950 void sctp_transport_set_owner(struct sctp_transport *,
951 			      struct sctp_association *);
952 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
953 			  struct sctp_sock *);
954 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
955 void sctp_transport_free(struct sctp_transport *);
956 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
957 void sctp_transport_reset_hb_timer(struct sctp_transport *);
958 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
959 int sctp_transport_hold(struct sctp_transport *);
960 void sctp_transport_put(struct sctp_transport *);
961 void sctp_transport_update_rto(struct sctp_transport *, __u32);
962 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
963 void sctp_transport_lower_cwnd(struct sctp_transport *t,
964 			       enum sctp_lower_cwnd reason);
965 void sctp_transport_burst_limited(struct sctp_transport *);
966 void sctp_transport_burst_reset(struct sctp_transport *);
967 unsigned long sctp_transport_timeout(struct sctp_transport *);
968 void sctp_transport_reset(struct sctp_transport *t);
969 void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
970 void sctp_transport_immediate_rtx(struct sctp_transport *);
971 void sctp_transport_dst_release(struct sctp_transport *t);
972 void sctp_transport_dst_confirm(struct sctp_transport *t);
973 
974 
975 /* This is the structure we use to queue packets as they come into
976  * SCTP.  We write packets to it and read chunks from it.
977  */
978 struct sctp_inq {
979 	/* This is actually a queue of sctp_chunk each
980 	 * containing a partially decoded packet.
981 	 */
982 	struct list_head in_chunk_list;
983 	/* This is the packet which is currently off the in queue and is
984 	 * being worked on through the inbound chunk processing.
985 	 */
986 	struct sctp_chunk *in_progress;
987 
988 	/* This is the delayed task to finish delivering inbound
989 	 * messages.
990 	 */
991 	struct work_struct immediate;
992 };
993 
994 void sctp_inq_init(struct sctp_inq *);
995 void sctp_inq_free(struct sctp_inq *);
996 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
997 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
998 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
999 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1000 
1001 /* This is the structure we use to hold outbound chunks.  You push
1002  * chunks in and they automatically pop out the other end as bundled
1003  * packets (it calls (*output_handler)()).
1004  *
1005  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1006  * and 8.2 of the v13 draft.
1007  *
1008  * It handles retransmissions.	The connection to the timeout portion
1009  * of the state machine is through sctp_..._timeout() and timeout_handler.
1010  *
1011  * If you feed it SACKs, it will eat them.
1012  *
1013  * If you give it big chunks, it will fragment them.
1014  *
1015  * It assigns TSN's to data chunks.  This happens at the last possible
1016  * instant before transmission.
1017  *
1018  * When free()'d, it empties itself out via output_handler().
1019  */
1020 struct sctp_outq {
1021 	struct sctp_association *asoc;
1022 
1023 	/* Data pending that has never been transmitted.  */
1024 	struct list_head out_chunk_list;
1025 
1026 	/* Stream scheduler being used */
1027 	struct sctp_sched_ops *sched;
1028 
1029 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1030 
1031 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1032 	unsigned int error;
1033 
1034 	/* These are control chunks we want to send.  */
1035 	struct list_head control_chunk_list;
1036 
1037 	/* These are chunks that have been sacked but are above the
1038 	 * CTSN, or cumulative tsn ack point.
1039 	 */
1040 	struct list_head sacked;
1041 
1042 	/* Put chunks on this list to schedule them for
1043 	 * retransmission.
1044 	 */
1045 	struct list_head retransmit;
1046 
1047 	/* Put chunks on this list to save them for FWD TSN processing as
1048 	 * they were abandoned.
1049 	 */
1050 	struct list_head abandoned;
1051 
1052 	/* How many unackd bytes do we have in-flight?	*/
1053 	__u32 outstanding_bytes;
1054 
1055 	/* Are we doing fast-rtx on this queue */
1056 	char fast_rtx;
1057 
1058 	/* Corked? */
1059 	char cork;
1060 };
1061 
1062 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1063 void sctp_outq_teardown(struct sctp_outq *);
1064 void sctp_outq_free(struct sctp_outq*);
1065 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1066 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1067 int sctp_outq_is_empty(const struct sctp_outq *);
1068 void sctp_outq_restart(struct sctp_outq *);
1069 
1070 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1071 		     enum sctp_retransmit_reason reason);
1072 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1073 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1074 void sctp_prsctp_prune(struct sctp_association *asoc,
1075 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1076 /* Uncork and flush an outqueue.  */
1077 static inline void sctp_outq_cork(struct sctp_outq *q)
1078 {
1079 	q->cork = 1;
1080 }
1081 
1082 /* SCTP skb control block.
1083  * sctp_input_cb is currently used on rx and sock rx queue
1084  */
1085 struct sctp_input_cb {
1086 	union {
1087 		struct inet_skb_parm	h4;
1088 #if IS_ENABLED(CONFIG_IPV6)
1089 		struct inet6_skb_parm	h6;
1090 #endif
1091 	} header;
1092 	struct sctp_chunk *chunk;
1093 	struct sctp_af *af;
1094 };
1095 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1096 
1097 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1098 {
1099 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1100 
1101 	return chunk->head_skb ? : skb;
1102 }
1103 
1104 /* These bind address data fields common between endpoints and associations */
1105 struct sctp_bind_addr {
1106 
1107 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1108 	 *
1109 	 * SCTP Port:	The local SCTP port number the endpoint is
1110 	 *		bound to.
1111 	 */
1112 	__u16 port;
1113 
1114 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1115 	 *
1116 	 * Address List: The list of IP addresses that this instance
1117 	 *	has bound.  This information is passed to one's
1118 	 *	peer(s) in INIT and INIT ACK chunks.
1119 	 */
1120 	struct list_head address_list;
1121 };
1122 
1123 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1124 void sctp_bind_addr_free(struct sctp_bind_addr *);
1125 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1126 			const struct sctp_bind_addr *src,
1127 			enum sctp_scope scope, gfp_t gfp,
1128 			int flags);
1129 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1130 			const struct sctp_bind_addr *src,
1131 			gfp_t gfp);
1132 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1133 		       int new_size, __u8 addr_state, gfp_t gfp);
1134 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1135 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1136 			 struct sctp_sock *);
1137 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1138 			 struct sctp_sock *, struct sctp_sock *);
1139 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1140 			 const union sctp_addr *addr);
1141 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1142 					const union sctp_addr	*addrs,
1143 					int			addrcnt,
1144 					struct sctp_sock	*opt);
1145 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1146 					 int *addrs_len,
1147 					 gfp_t gfp);
1148 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1149 			   __u16 port, gfp_t gfp);
1150 
1151 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1152 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1153 		  const enum sctp_scope scope);
1154 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1155 int sctp_is_ep_boundall(struct sock *sk);
1156 
1157 
1158 /* What type of endpoint?  */
1159 enum sctp_endpoint_type {
1160 	SCTP_EP_TYPE_SOCKET,
1161 	SCTP_EP_TYPE_ASSOCIATION,
1162 };
1163 
1164 /*
1165  * A common base class to bridge the implmentation view of a
1166  * socket (usually listening) endpoint versus an association's
1167  * local endpoint.
1168  * This common structure is useful for several purposes:
1169  *   1) Common interface for lookup routines.
1170  *	a) Subfunctions work for either endpoint or association
1171  *	b) Single interface to lookup allows hiding the lookup lock rather
1172  *	   than acquiring it externally.
1173  *   2) Common interface for the inbound chunk handling/state machine.
1174  *   3) Common object handling routines for reference counting, etc.
1175  *   4) Disentangle association lookup from endpoint lookup, where we
1176  *	do not have to find our endpoint to find our association.
1177  *
1178  */
1179 
1180 struct sctp_ep_common {
1181 	/* Fields to help us manage our entries in the hash tables. */
1182 	struct hlist_node node;
1183 	int hashent;
1184 
1185 	/* Runtime type information.  What kind of endpoint is this? */
1186 	enum sctp_endpoint_type type;
1187 
1188 	/* Some fields to help us manage this object.
1189 	 *   refcnt   - Reference count access to this object.
1190 	 *   dead     - Do not attempt to use this object.
1191 	 */
1192 	refcount_t    refcnt;
1193 	bool	    dead;
1194 
1195 	/* What socket does this endpoint belong to?  */
1196 	struct sock *sk;
1197 
1198 	/* This is where we receive inbound chunks.  */
1199 	struct sctp_inq	  inqueue;
1200 
1201 	/* This substructure includes the defining parameters of the
1202 	 * endpoint:
1203 	 * bind_addr.port is our shared port number.
1204 	 * bind_addr.address_list is our set of local IP addresses.
1205 	 */
1206 	struct sctp_bind_addr bind_addr;
1207 };
1208 
1209 
1210 /* RFC Section 1.4 Key Terms
1211  *
1212  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1213  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1214  *   combination of a set of eligible destination transport addresses to
1215  *   which SCTP packets can be sent and a set of eligible source
1216  *   transport addresses from which SCTP packets can be received.
1217  *   All transport addresses used by an SCTP endpoint must use the
1218  *   same port number, but can use multiple IP addresses. A transport
1219  *   address used by an SCTP endpoint must not be used by another
1220  *   SCTP endpoint. In other words, a transport address is unique
1221  *   to an SCTP endpoint.
1222  *
1223  * From an implementation perspective, each socket has one of these.
1224  * A TCP-style socket will have exactly one association on one of
1225  * these.  An UDP-style socket will have multiple associations hanging
1226  * off one of these.
1227  */
1228 
1229 struct sctp_endpoint {
1230 	/* Common substructure for endpoint and association. */
1231 	struct sctp_ep_common base;
1232 
1233 	/* Associations: A list of current associations and mappings
1234 	 *	      to the data consumers for each association. This
1235 	 *	      may be in the form of a hash table or other
1236 	 *	      implementation dependent structure. The data
1237 	 *	      consumers may be process identification
1238 	 *	      information such as file descriptors, named pipe
1239 	 *	      pointer, or table pointers dependent on how SCTP
1240 	 *	      is implemented.
1241 	 */
1242 	/* This is really a list of struct sctp_association entries. */
1243 	struct list_head asocs;
1244 
1245 	/* Secret Key: A secret key used by this endpoint to compute
1246 	 *	      the MAC.	This SHOULD be a cryptographic quality
1247 	 *	      random number with a sufficient length.
1248 	 *	      Discussion in [RFC1750] can be helpful in
1249 	 *	      selection of the key.
1250 	 */
1251 	__u8 secret_key[SCTP_SECRET_SIZE];
1252 
1253  	/* digest:  This is a digest of the sctp cookie.  This field is
1254  	 * 	    only used on the receive path when we try to validate
1255  	 * 	    that the cookie has not been tampered with.  We put
1256  	 * 	    this here so we pre-allocate this once and can re-use
1257  	 * 	    on every receive.
1258  	 */
1259  	__u8 *digest;
1260 
1261 	/* sendbuf acct. policy.	*/
1262 	__u32 sndbuf_policy;
1263 
1264 	/* rcvbuf acct. policy.	*/
1265 	__u32 rcvbuf_policy;
1266 
1267 	/* SCTP AUTH: array of the HMACs that will be allocated
1268 	 * we need this per association so that we don't serialize
1269 	 */
1270 	struct crypto_shash **auth_hmacs;
1271 
1272 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1273 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1274 
1275 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1276 	struct sctp_chunks_param *auth_chunk_list;
1277 
1278 	/* SCTP-AUTH: endpoint shared keys */
1279 	struct list_head endpoint_shared_keys;
1280 	__u16 active_key_id;
1281 	__u8  auth_enable:1,
1282 	      prsctp_enable:1,
1283 	      reconf_enable:1;
1284 
1285 	__u8  strreset_enable;
1286 };
1287 
1288 /* Recover the outter endpoint structure. */
1289 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1290 {
1291 	struct sctp_endpoint *ep;
1292 
1293 	ep = container_of(base, struct sctp_endpoint, base);
1294 	return ep;
1295 }
1296 
1297 /* These are function signatures for manipulating endpoints.  */
1298 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1299 void sctp_endpoint_free(struct sctp_endpoint *);
1300 void sctp_endpoint_put(struct sctp_endpoint *);
1301 void sctp_endpoint_hold(struct sctp_endpoint *);
1302 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1303 struct sctp_association *sctp_endpoint_lookup_assoc(
1304 	const struct sctp_endpoint *ep,
1305 	const union sctp_addr *paddr,
1306 	struct sctp_transport **);
1307 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1308 				const union sctp_addr *);
1309 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1310 					struct net *, const union sctp_addr *);
1311 int sctp_has_association(struct net *net, const union sctp_addr *laddr,
1312 			 const union sctp_addr *paddr);
1313 
1314 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1315 		     const struct sctp_association *asoc,
1316 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1317 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1318 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1319 		      const union sctp_addr *peer,
1320 		      struct sctp_init_chunk *init, gfp_t gfp);
1321 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1322 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1323 
1324 struct sctp_inithdr_host {
1325 	__u32 init_tag;
1326 	__u32 a_rwnd;
1327 	__u16 num_outbound_streams;
1328 	__u16 num_inbound_streams;
1329 	__u32 initial_tsn;
1330 };
1331 
1332 struct sctp_stream_priorities {
1333 	/* List of priorities scheduled */
1334 	struct list_head prio_sched;
1335 	/* List of streams scheduled */
1336 	struct list_head active;
1337 	/* The next stream stream in line */
1338 	struct sctp_stream_out_ext *next;
1339 	__u16 prio;
1340 };
1341 
1342 struct sctp_stream_out_ext {
1343 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1344 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1345 	struct list_head outq; /* chunks enqueued by this stream */
1346 	union {
1347 		struct {
1348 			/* Scheduled streams list */
1349 			struct list_head prio_list;
1350 			struct sctp_stream_priorities *prio_head;
1351 		};
1352 		/* Fields used by RR scheduler */
1353 		struct {
1354 			struct list_head rr_list;
1355 		};
1356 	};
1357 };
1358 
1359 struct sctp_stream_out {
1360 	__u16	ssn;
1361 	__u8	state;
1362 	struct sctp_stream_out_ext *ext;
1363 };
1364 
1365 struct sctp_stream_in {
1366 	__u16	ssn;
1367 };
1368 
1369 struct sctp_stream {
1370 	struct sctp_stream_out *out;
1371 	struct sctp_stream_in *in;
1372 	__u16 outcnt;
1373 	__u16 incnt;
1374 	/* Current stream being sent, if any */
1375 	struct sctp_stream_out *out_curr;
1376 	union {
1377 		/* Fields used by priority scheduler */
1378 		struct {
1379 			/* List of priorities scheduled */
1380 			struct list_head prio_list;
1381 		};
1382 		/* Fields used by RR scheduler */
1383 		struct {
1384 			/* List of streams scheduled */
1385 			struct list_head rr_list;
1386 			/* The next stream stream in line */
1387 			struct sctp_stream_out_ext *rr_next;
1388 		};
1389 	};
1390 };
1391 
1392 #define SCTP_STREAM_CLOSED		0x00
1393 #define SCTP_STREAM_OPEN		0x01
1394 
1395 /* SCTP_GET_ASSOC_STATS counters */
1396 struct sctp_priv_assoc_stats {
1397 	/* Maximum observed rto in the association during subsequent
1398 	 * observations. Value is set to 0 if no RTO measurement took place
1399 	 * The transport where the max_rto was observed is returned in
1400 	 * obs_rto_ipaddr
1401 	 */
1402 	struct sockaddr_storage obs_rto_ipaddr;
1403 	__u64 max_obs_rto;
1404 	/* Total In and Out SACKs received and sent */
1405 	__u64 isacks;
1406 	__u64 osacks;
1407 	/* Total In and Out packets received and sent */
1408 	__u64 opackets;
1409 	__u64 ipackets;
1410 	/* Total retransmitted chunks */
1411 	__u64 rtxchunks;
1412 	/* TSN received > next expected */
1413 	__u64 outofseqtsns;
1414 	/* Duplicate Chunks received */
1415 	__u64 idupchunks;
1416 	/* Gap Ack Blocks received */
1417 	__u64 gapcnt;
1418 	/* Unordered data chunks sent and received */
1419 	__u64 ouodchunks;
1420 	__u64 iuodchunks;
1421 	/* Ordered data chunks sent and received */
1422 	__u64 oodchunks;
1423 	__u64 iodchunks;
1424 	/* Control chunks sent and received */
1425 	__u64 octrlchunks;
1426 	__u64 ictrlchunks;
1427 };
1428 
1429 /* RFC2960
1430  *
1431  * 12. Recommended Transmission Control Block (TCB) Parameters
1432  *
1433  * This section details a recommended set of parameters that should
1434  * be contained within the TCB for an implementation. This section is
1435  * for illustrative purposes and should not be deemed as requirements
1436  * on an implementation or as an exhaustive list of all parameters
1437  * inside an SCTP TCB. Each implementation may need its own additional
1438  * parameters for optimization.
1439  */
1440 
1441 
1442 /* Here we have information about each individual association. */
1443 struct sctp_association {
1444 
1445 	/* A base structure common to endpoint and association.
1446 	 * In this context, it represents the associations's view
1447 	 * of the local endpoint of the association.
1448 	 */
1449 	struct sctp_ep_common base;
1450 
1451 	/* Associations on the same socket. */
1452 	struct list_head asocs;
1453 
1454 	/* association id. */
1455 	sctp_assoc_t assoc_id;
1456 
1457 	/* This is our parent endpoint.	 */
1458 	struct sctp_endpoint *ep;
1459 
1460 	/* These are those association elements needed in the cookie.  */
1461 	struct sctp_cookie c;
1462 
1463 	/* This is all information about our peer.  */
1464 	struct {
1465 		/* transport_addr_list
1466 		 *
1467 		 * Peer	       : A list of SCTP transport addresses that the
1468 		 * Transport   : peer is bound to. This information is derived
1469 		 * Address     : from the INIT or INIT ACK and is used to
1470 		 * List	       : associate an inbound packet with a given
1471 		 *	       : association. Normally this information is
1472 		 *	       : hashed or keyed for quick lookup and access
1473 		 *	       : of the TCB.
1474 		 *	       : The list is also initialized with the list
1475 		 *	       : of addresses passed with the sctp_connectx()
1476 		 *	       : call.
1477 		 *
1478 		 * It is a list of SCTP_transport's.
1479 		 */
1480 		struct list_head transport_addr_list;
1481 
1482 		/* rwnd
1483 		 *
1484 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1485 		 */
1486 		__u32 rwnd;
1487 
1488 		/* transport_count
1489 		 *
1490 		 * Peer        : A count of the number of peer addresses
1491 		 * Transport   : in the Peer Transport Address List.
1492 		 * Address     :
1493 		 * Count       :
1494 		 */
1495 		__u16 transport_count;
1496 
1497 		/* port
1498 		 *   The transport layer port number.
1499 		 */
1500 		__u16 port;
1501 
1502 		/* primary_path
1503 		 *
1504 		 * Primary     : This is the current primary destination
1505 		 * Path	       : transport address of the peer endpoint.  It
1506 		 *	       : may also specify a source transport address
1507 		 *	       : on this endpoint.
1508 		 *
1509 		 * All of these paths live on transport_addr_list.
1510 		 *
1511 		 * At the bakeoffs, we discovered that the intent of
1512 		 * primaryPath is that it only changes when the ULP
1513 		 * asks to have it changed.  We add the activePath to
1514 		 * designate the connection we are currently using to
1515 		 * transmit new data and most control chunks.
1516 		 */
1517 		struct sctp_transport *primary_path;
1518 
1519 		/* Cache the primary path address here, when we
1520 		 * need a an address for msg_name.
1521 		 */
1522 		union sctp_addr primary_addr;
1523 
1524 		/* active_path
1525 		 *   The path that we are currently using to
1526 		 *   transmit new data and most control chunks.
1527 		 */
1528 		struct sctp_transport *active_path;
1529 
1530 		/* retran_path
1531 		 *
1532 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1533 		 * ...
1534 		 * Furthermore, when its peer is multi-homed, an
1535 		 * endpoint SHOULD try to retransmit a chunk to an
1536 		 * active destination transport address that is
1537 		 * different from the last destination address to
1538 		 * which the DATA chunk was sent.
1539 		 */
1540 		struct sctp_transport *retran_path;
1541 
1542 		/* Pointer to last transport I have sent on.  */
1543 		struct sctp_transport *last_sent_to;
1544 
1545 		/* This is the last transport I have received DATA on.	*/
1546 		struct sctp_transport *last_data_from;
1547 
1548 		/*
1549 		 * Mapping  An array of bits or bytes indicating which out of
1550 		 * Array    order TSN's have been received (relative to the
1551 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1552 		 *	    order packets have been received, this array
1553 		 *	    will be set to all zero. This structure may be
1554 		 *	    in the form of a circular buffer or bit array.
1555 		 *
1556 		 * Last Rcvd   : This is the last TSN received in
1557 		 * TSN	       : sequence. This value is set initially by
1558 		 *	       : taking the peer's Initial TSN, received in
1559 		 *	       : the INIT or INIT ACK chunk, and subtracting
1560 		 *	       : one from it.
1561 		 *
1562 		 * Throughout most of the specification this is called the
1563 		 * "Cumulative TSN ACK Point".	In this case, we
1564 		 * ignore the advice in 12.2 in favour of the term
1565 		 * used in the bulk of the text.  This value is hidden
1566 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1567 		 */
1568 		struct sctp_tsnmap tsn_map;
1569 
1570 		/* This mask is used to disable sending the ASCONF chunk
1571 		 * with specified parameter to peer.
1572 		 */
1573 		__be16 addip_disabled_mask;
1574 
1575 		/* These are capabilities which our peer advertised.  */
1576 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1577 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1578 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1579 			hostname_address:1, /* Peer understands DNS addresses? */
1580 			asconf_capable:1,   /* Does peer support ADDIP? */
1581 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1582 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1583 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1584 
1585 		/* sack_needed : This flag indicates if the next received
1586 		 *             : packet is to be responded to with a
1587 		 *             : SACK. This is initialized to 0.  When a packet
1588 		 *             : is received sack_cnt is incremented. If this value
1589 		 *             : reaches 2 or more, a SACK is sent and the
1590 		 *             : value is reset to 0. Note: This is used only
1591 		 *             : when no DATA chunks are received out of
1592 		 *             : order.  When DATA chunks are out of order,
1593 		 *             : SACK's are not delayed (see Section 6).
1594 		 */
1595 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1596 			sack_generation:1,
1597 			zero_window_announced:1;
1598 		__u32	sack_cnt;
1599 
1600 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1601 
1602 		struct sctp_inithdr_host i;
1603 		void *cookie;
1604 		int cookie_len;
1605 
1606 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1607 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1608 		 * Initial TSN Value minus 1
1609 		 */
1610 		__u32 addip_serial;
1611 
1612 		/* SCTP-AUTH: We need to know pears random number, hmac list
1613 		 * and authenticated chunk list.  All that is part of the
1614 		 * cookie and these are just pointers to those locations
1615 		 */
1616 		struct sctp_random_param *peer_random;
1617 		struct sctp_chunks_param *peer_chunks;
1618 		struct sctp_hmac_algo_param *peer_hmacs;
1619 	} peer;
1620 
1621 	/* State       : A state variable indicating what state the
1622 	 *	       : association is in, i.e. COOKIE-WAIT,
1623 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1624 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1625 	 *
1626 	 *		Note: No "CLOSED" state is illustrated since if a
1627 	 *		association is "CLOSED" its TCB SHOULD be removed.
1628 	 *
1629 	 *		In this implementation we DO have a CLOSED
1630 	 *		state which is used during initiation and shutdown.
1631 	 *
1632 	 *		State takes values from SCTP_STATE_*.
1633 	 */
1634 	enum sctp_state state;
1635 
1636 	/* Overall     : The overall association error count.
1637 	 * Error Count : [Clear this any time I get something.]
1638 	 */
1639 	int overall_error_count;
1640 
1641 	/* The cookie life I award for any cookie.  */
1642 	ktime_t cookie_life;
1643 
1644 	/* These are the association's initial, max, and min RTO values.
1645 	 * These values will be initialized by system defaults, but can
1646 	 * be modified via the SCTP_RTOINFO socket option.
1647 	 */
1648 	unsigned long rto_initial;
1649 	unsigned long rto_max;
1650 	unsigned long rto_min;
1651 
1652 	/* Maximum number of new data packets that can be sent in a burst.  */
1653 	int max_burst;
1654 
1655 	/* This is the max_retrans value for the association.  This value will
1656 	 * be initialized initialized from system defaults, but can be
1657 	 * modified by the SCTP_ASSOCINFO socket option.
1658 	 */
1659 	int max_retrans;
1660 
1661 	/* This is the partially failed retrans value for the transport
1662 	 * and will be initialized from the assocs value.  This can be
1663 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1664 	 */
1665 	int pf_retrans;
1666 
1667 	/* Maximum number of times the endpoint will retransmit INIT  */
1668 	__u16 max_init_attempts;
1669 
1670 	/* How many times have we resent an INIT? */
1671 	__u16 init_retries;
1672 
1673 	/* The largest timeout or RTO value to use in attempting an INIT */
1674 	unsigned long max_init_timeo;
1675 
1676 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1677 	 * the destination address every heartbeat interval. This value
1678 	 * will be inherited by all new transports.
1679 	 */
1680 	unsigned long hbinterval;
1681 
1682 	/* This is the max_retrans value for new transports in the
1683 	 * association.
1684 	 */
1685 	__u16 pathmaxrxt;
1686 
1687 	/* Flag that path mtu update is pending */
1688 	__u8   pmtu_pending;
1689 
1690 	/* Association : The smallest PMTU discovered for all of the
1691 	 * PMTU	       : peer's transport addresses.
1692 	 */
1693 	__u32 pathmtu;
1694 
1695 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1696 	__u32 param_flags;
1697 
1698 	__u32 sackfreq;
1699 	/* SACK delay timeout */
1700 	unsigned long sackdelay;
1701 
1702 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1703 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1704 
1705 	/* Transport to which SHUTDOWN chunk was last sent.  */
1706 	struct sctp_transport *shutdown_last_sent_to;
1707 
1708 	/* Transport to which INIT chunk was last sent.  */
1709 	struct sctp_transport *init_last_sent_to;
1710 
1711 	/* How many times have we resent a SHUTDOWN */
1712 	int shutdown_retries;
1713 
1714 	/* Next TSN    : The next TSN number to be assigned to a new
1715 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1716 	 *	       : ACK chunk to the peer and incremented each
1717 	 *	       : time a DATA chunk is assigned a TSN
1718 	 *	       : (normally just prior to transmit or during
1719 	 *	       : fragmentation).
1720 	 */
1721 	__u32 next_tsn;
1722 
1723 	/*
1724 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1725 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1726 	 *	       : received in the INIT or INIT ACK chunk, and
1727 	 *	       : subtracting one from it.
1728 	 *
1729 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1730 	 */
1731 
1732 	__u32 ctsn_ack_point;
1733 
1734 	/* PR-SCTP Advanced.Peer.Ack.Point */
1735 	__u32 adv_peer_ack_point;
1736 
1737 	/* Highest TSN that is acknowledged by incoming SACKs. */
1738 	__u32 highest_sacked;
1739 
1740 	/* TSN marking the fast recovery exit point */
1741 	__u32 fast_recovery_exit;
1742 
1743 	/* Flag to track the current fast recovery state */
1744 	__u8 fast_recovery;
1745 
1746 	/* The number of unacknowledged data chunks.  Reported through
1747 	 * the SCTP_STATUS sockopt.
1748 	 */
1749 	__u16 unack_data;
1750 
1751 	/* The total number of data chunks that we've had to retransmit
1752 	 * as the result of a T3 timer expiration
1753 	 */
1754 	__u32 rtx_data_chunks;
1755 
1756 	/* This is the association's receive buffer space.  This value is used
1757 	 * to set a_rwnd field in an INIT or a SACK chunk.
1758 	 */
1759 	__u32 rwnd;
1760 
1761 	/* This is the last advertised value of rwnd over a SACK chunk. */
1762 	__u32 a_rwnd;
1763 
1764 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1765 	 * to slop over a maximum of the association's frag_point.
1766 	 */
1767 	__u32 rwnd_over;
1768 
1769 	/* Keeps treack of rwnd pressure.  This happens when we have
1770 	 * a window, but not recevie buffer (i.e small packets).  This one
1771 	 * is releases slowly (1 PMTU at a time ).
1772 	 */
1773 	__u32 rwnd_press;
1774 
1775 	/* This is the sndbuf size in use for the association.
1776 	 * This corresponds to the sndbuf size for the association,
1777 	 * as specified in the sk->sndbuf.
1778 	 */
1779 	int sndbuf_used;
1780 
1781 	/* This is the amount of memory that this association has allocated
1782 	 * in the receive path at any given time.
1783 	 */
1784 	atomic_t rmem_alloc;
1785 
1786 	/* This is the wait queue head for send requests waiting on
1787 	 * the association sndbuf space.
1788 	 */
1789 	wait_queue_head_t	wait;
1790 
1791 	/* The message size at which SCTP fragmentation will occur. */
1792 	__u32 frag_point;
1793 	__u32 user_frag;
1794 
1795 	/* Counter used to count INIT errors. */
1796 	int init_err_counter;
1797 
1798 	/* Count the number of INIT cycles (for doubling timeout). */
1799 	int init_cycle;
1800 
1801 	/* Default send parameters. */
1802 	__u16 default_stream;
1803 	__u16 default_flags;
1804 	__u32 default_ppid;
1805 	__u32 default_context;
1806 	__u32 default_timetolive;
1807 
1808 	/* Default receive parameters */
1809 	__u32 default_rcv_context;
1810 
1811 	/* Stream arrays */
1812 	struct sctp_stream stream;
1813 
1814 	/* All outbound chunks go through this structure.  */
1815 	struct sctp_outq outqueue;
1816 
1817 	/* A smart pipe that will handle reordering and fragmentation,
1818 	 * as well as handle passing events up to the ULP.
1819 	 */
1820 	struct sctp_ulpq ulpq;
1821 
1822 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1823 	__u32 last_ecne_tsn;
1824 
1825 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1826 	__u32 last_cwr_tsn;
1827 
1828 	/* How many duplicated TSNs have we seen?  */
1829 	int numduptsns;
1830 
1831 	/* These are to support
1832 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1833 	 *  and Enforcement of Flow and Message Limits"
1834 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1835 	 * or "ADDIP" for short.
1836 	 */
1837 
1838 
1839 
1840 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1841 	 *
1842 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1843 	 * unacknowledged at any one time.  If a sender, after sending
1844 	 * an ASCONF chunk, decides it needs to transfer another
1845 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1846 	 * returns from the previous ASCONF Chunk before sending a
1847 	 * subsequent ASCONF. Note this restriction binds each side,
1848 	 * so at any time two ASCONF may be in-transit on any given
1849 	 * association (one sent from each endpoint).
1850 	 *
1851 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1852 	 * not have an ASCONF in flight, this is NULL.]
1853 	 */
1854 	struct sctp_chunk *addip_last_asconf;
1855 
1856 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1857 	 *
1858 	 * This is needed to implement itmes E1 - E4 of the updated
1859 	 * spec.  Here is the justification:
1860 	 *
1861 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1862 	 * we now need the ability to cache multiple ACKs.  The section
1863 	 * describes in detail how they are cached and cleaned up.
1864 	 */
1865 	struct list_head asconf_ack_list;
1866 
1867 	/* These ASCONF chunks are waiting to be sent.
1868 	 *
1869 	 * These chunaks can't be pushed to outqueue until receiving
1870 	 * ASCONF_ACK for the previous ASCONF indicated by
1871 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1872 	 * is in flight at any time.
1873 	 *
1874 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1875 	 *
1876 	 * In defining the ASCONF Chunk transfer procedures, it is
1877 	 * essential that these transfers MUST NOT cause congestion
1878 	 * within the network.	To achieve this, we place these
1879 	 * restrictions on the transfer of ASCONF Chunks:
1880 	 *
1881 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1882 	 * unacknowledged at any one time.  If a sender, after sending
1883 	 * an ASCONF chunk, decides it needs to transfer another
1884 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1885 	 * returns from the previous ASCONF Chunk before sending a
1886 	 * subsequent ASCONF. Note this restriction binds each side,
1887 	 * so at any time two ASCONF may be in-transit on any given
1888 	 * association (one sent from each endpoint).
1889 	 *
1890 	 *
1891 	 * [I really think this is EXACTLY the sort of intelligence
1892 	 *  which already resides in sctp_outq.	 Please move this
1893 	 *  queue and its supporting logic down there.	--piggy]
1894 	 */
1895 	struct list_head addip_chunk_list;
1896 
1897 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1898 	 *
1899 	 * A2) A serial number should be assigned to the Chunk. The
1900 	 * serial number SHOULD be a monotonically increasing
1901 	 * number. The serial number SHOULD be initialized at
1902 	 * the start of the association to the same value as the
1903 	 * Initial TSN and every time a new ASCONF chunk is created
1904 	 * it is incremented by one after assigning the serial number
1905 	 * to the newly created chunk.
1906 	 *
1907 	 * ADDIP
1908 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1909 	 *
1910 	 * Serial Number : 32 bits (unsigned integer)
1911 	 *
1912 	 * This value represents a Serial Number for the ASCONF
1913 	 * Chunk. The valid range of Serial Number is from 0 to
1914 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1915 	 * after reaching 4294967295.
1916 	 */
1917 	__u32 addip_serial;
1918 	int src_out_of_asoc_ok;
1919 	union sctp_addr *asconf_addr_del_pending;
1920 	struct sctp_transport *new_transport;
1921 
1922 	/* SCTP AUTH: list of the endpoint shared keys.  These
1923 	 * keys are provided out of band by the user applicaton
1924 	 * and can't change during the lifetime of the association
1925 	 */
1926 	struct list_head endpoint_shared_keys;
1927 
1928 	/* SCTP AUTH:
1929 	 * The current generated assocaition shared key (secret)
1930 	 */
1931 	struct sctp_auth_bytes *asoc_shared_key;
1932 
1933 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1934 	 * that we support.
1935 	 */
1936 	__u16 default_hmac_id;
1937 
1938 	__u16 active_key_id;
1939 
1940 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
1941 	     temp:1,		/* Is it a temporary association? */
1942 	     force_delay:1,
1943 	     prsctp_enable:1,
1944 	     reconf_enable:1;
1945 
1946 	__u8 strreset_enable;
1947 	__u8 strreset_outstanding; /* request param count on the fly */
1948 
1949 	__u32 strreset_outseq; /* Update after receiving response */
1950 	__u32 strreset_inseq; /* Update after receiving request */
1951 	__u32 strreset_result[2]; /* save the results of last 2 responses */
1952 
1953 	struct sctp_chunk *strreset_chunk; /* save request chunk */
1954 
1955 	struct sctp_priv_assoc_stats stats;
1956 
1957 	int sent_cnt_removable;
1958 
1959 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1960 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1961 };
1962 
1963 
1964 /* An eyecatcher for determining if we are really looking at an
1965  * association data structure.
1966  */
1967 enum {
1968 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1969 };
1970 
1971 /* Recover the outter association structure. */
1972 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1973 {
1974 	struct sctp_association *asoc;
1975 
1976 	asoc = container_of(base, struct sctp_association, base);
1977 	return asoc;
1978 }
1979 
1980 /* These are function signatures for manipulating associations.	 */
1981 
1982 
1983 struct sctp_association *
1984 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
1985 		     enum sctp_scope scope, gfp_t gfp);
1986 void sctp_association_free(struct sctp_association *);
1987 void sctp_association_put(struct sctp_association *);
1988 void sctp_association_hold(struct sctp_association *);
1989 
1990 struct sctp_transport *sctp_assoc_choose_alter_transport(
1991 	struct sctp_association *, struct sctp_transport *);
1992 void sctp_assoc_update_retran_path(struct sctp_association *);
1993 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1994 					  const union sctp_addr *);
1995 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1996 			    const union sctp_addr *laddr);
1997 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
1998 				     const union sctp_addr *address,
1999 				     const gfp_t gfp,
2000 				     const int peer_state);
2001 void sctp_assoc_del_peer(struct sctp_association *asoc,
2002 			 const union sctp_addr *addr);
2003 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2004 			 struct sctp_transport *peer);
2005 void sctp_assoc_control_transport(struct sctp_association *asoc,
2006 				  struct sctp_transport *transport,
2007 				  enum sctp_transport_cmd command,
2008 				  sctp_sn_error_t error);
2009 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2010 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
2011 					   struct net *,
2012 					   const union sctp_addr *,
2013 					   const union sctp_addr *);
2014 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2015 int sctp_assoc_update(struct sctp_association *old,
2016 		      struct sctp_association *new);
2017 
2018 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2019 
2020 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2021 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2022 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2023 void sctp_assoc_set_primary(struct sctp_association *,
2024 			    struct sctp_transport *);
2025 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2026 				    struct sctp_transport *);
2027 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2028 				     enum sctp_scope scope, gfp_t gfp);
2029 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2030 					 struct sctp_cookie*,
2031 					 gfp_t gfp);
2032 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2033 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2034 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2035 					const struct sctp_association *asoc,
2036 					__be32 serial);
2037 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2038 
2039 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2040 			const union sctp_addr *ss2);
2041 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2042 
2043 /* A convenience structure to parse out SCTP specific CMSGs. */
2044 struct sctp_cmsgs {
2045 	struct sctp_initmsg *init;
2046 	struct sctp_sndrcvinfo *srinfo;
2047 	struct sctp_sndinfo *sinfo;
2048 };
2049 
2050 /* Structure for tracking memory objects */
2051 struct sctp_dbg_objcnt_entry {
2052 	char *label;
2053 	atomic_t *counter;
2054 };
2055 
2056 #endif /* __sctp_structs_h__ */
2057