xref: /openbmc/linux/include/net/sctp/structs.h (revision a0ae2562c6c4b2721d9fddba63b7286c13517d9f)
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-types.h>
52 #include <linux/socket.h>	/* linux/in.h needs this!!    */
53 #include <linux/in.h>		/* We get struct sockaddr_in. */
54 #include <linux/in6.h>		/* We get struct in6_addr     */
55 #include <linux/ipv6.h>
56 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
57 #include <linux/atomic.h>		/* This gets us atomic counters.  */
58 #include <linux/skbuff.h>	/* We need sk_buff_head. */
59 #include <linux/workqueue.h>	/* We need tq_struct.	 */
60 #include <linux/sctp.h>		/* We need sctp* header structs.  */
61 #include <net/sctp/auth.h>	/* We need auth specific structs */
62 #include <net/ip.h>		/* For inet_skb_parm */
63 
64 /* A convenience structure for handling sockaddr structures.
65  * We should wean ourselves off this.
66  */
67 union sctp_addr {
68 	struct sockaddr_in v4;
69 	struct sockaddr_in6 v6;
70 	struct sockaddr sa;
71 };
72 
73 /* Forward declarations for data structures. */
74 struct sctp_globals;
75 struct sctp_endpoint;
76 struct sctp_association;
77 struct sctp_transport;
78 struct sctp_packet;
79 struct sctp_chunk;
80 struct sctp_inq;
81 struct sctp_outq;
82 struct sctp_bind_addr;
83 struct sctp_ulpq;
84 struct sctp_ep_common;
85 struct crypto_shash;
86 struct sctp_stream;
87 
88 
89 #include <net/sctp/tsnmap.h>
90 #include <net/sctp/ulpevent.h>
91 #include <net/sctp/ulpqueue.h>
92 #include <net/sctp/stream_interleave.h>
93 
94 /* Structures useful for managing bind/connect. */
95 
96 struct sctp_bind_bucket {
97 	unsigned short	port;
98 	unsigned short	fastreuse;
99 	struct hlist_node	node;
100 	struct hlist_head	owner;
101 	struct net	*net;
102 };
103 
104 struct sctp_bind_hashbucket {
105 	spinlock_t	lock;
106 	struct hlist_head	chain;
107 };
108 
109 /* Used for hashing all associations.  */
110 struct sctp_hashbucket {
111 	rwlock_t	lock;
112 	struct hlist_head	chain;
113 } __attribute__((__aligned__(8)));
114 
115 
116 /* The SCTP globals structure. */
117 extern struct sctp_globals {
118 	/* This is a list of groups of functions for each address
119 	 * family that we support.
120 	 */
121 	struct list_head address_families;
122 
123 	/* This is the hash of all endpoints. */
124 	struct sctp_hashbucket *ep_hashtable;
125 	/* This is the sctp port control hash.	*/
126 	struct sctp_bind_hashbucket *port_hashtable;
127 	/* This is the hash of all transports. */
128 	struct rhltable transport_hashtable;
129 
130 	/* Sizes of above hashtables. */
131 	int ep_hashsize;
132 	int port_hashsize;
133 
134 	/* Default initialization values to be applied to new associations. */
135 	__u16 max_instreams;
136 	__u16 max_outstreams;
137 
138 	/* Flag to indicate whether computing and verifying checksum
139 	 * is disabled. */
140         bool checksum_disable;
141 } sctp_globals;
142 
143 #define sctp_max_instreams		(sctp_globals.max_instreams)
144 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
145 #define sctp_address_families		(sctp_globals.address_families)
146 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
147 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
148 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
149 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
150 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
151 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
152 
153 /* SCTP Socket type: UDP or TCP style. */
154 enum sctp_socket_type {
155 	SCTP_SOCKET_UDP = 0,
156 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
157 	SCTP_SOCKET_TCP
158 };
159 
160 /* Per socket SCTP information. */
161 struct sctp_sock {
162 	/* inet_sock has to be the first member of sctp_sock */
163 	struct inet_sock inet;
164 	/* What kind of a socket is this? */
165 	enum sctp_socket_type type;
166 
167 	/* PF_ family specific functions.  */
168 	struct sctp_pf *pf;
169 
170 	/* Access to HMAC transform. */
171 	struct crypto_shash *hmac;
172 	char *sctp_hmac_alg;
173 
174 	/* What is our base endpointer? */
175 	struct sctp_endpoint *ep;
176 
177 	struct sctp_bind_bucket *bind_hash;
178 	/* Various Socket Options.  */
179 	__u16 default_stream;
180 	__u32 default_ppid;
181 	__u16 default_flags;
182 	__u32 default_context;
183 	__u32 default_timetolive;
184 	__u32 default_rcv_context;
185 	int max_burst;
186 
187 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
188 	 * the destination address every heartbeat interval. This value
189 	 * will be inherited by all new associations.
190 	 */
191 	__u32 hbinterval;
192 
193 	/* This is the max_retrans value for new associations. */
194 	__u16 pathmaxrxt;
195 
196 	__u32 flowlabel;
197 	__u8  dscp;
198 
199 	/* The initial Path MTU to use for new associations. */
200 	__u32 pathmtu;
201 
202 	/* The default SACK delay timeout for new associations. */
203 	__u32 sackdelay;
204 	__u32 sackfreq;
205 
206 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
207 	__u32 param_flags;
208 
209 	struct sctp_rtoinfo rtoinfo;
210 	struct sctp_paddrparams paddrparam;
211 	struct sctp_assocparams assocparams;
212 
213 	/*
214 	 * These two structures must be grouped together for the usercopy
215 	 * whitelist region.
216 	 */
217 	struct sctp_event_subscribe subscribe;
218 	struct sctp_initmsg initmsg;
219 
220 	int user_frag;
221 
222 	__u32 autoclose;
223 	__u32 adaptation_ind;
224 	__u32 pd_point;
225 	__u16	nodelay:1,
226 		reuse:1,
227 		disable_fragments:1,
228 		v4mapped:1,
229 		frag_interleave:1,
230 		strm_interleave:1,
231 		recvrcvinfo:1,
232 		recvnxtinfo:1,
233 		data_ready_signalled:1;
234 
235 	atomic_t pd_mode;
236 	/* Receive to here while partial delivery is in effect. */
237 	struct sk_buff_head pd_lobby;
238 
239 	/* These must be the last fields, as they will skipped on copies,
240 	 * like on accept and peeloff operations
241 	 */
242 	struct list_head auto_asconf_list;
243 	int do_auto_asconf;
244 };
245 
246 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
247 {
248        return (struct sctp_sock *)sk;
249 }
250 
251 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
252 {
253        return (struct sock *)sp;
254 }
255 
256 #if IS_ENABLED(CONFIG_IPV6)
257 struct sctp6_sock {
258        struct sctp_sock  sctp;
259        struct ipv6_pinfo inet6;
260 };
261 #endif /* CONFIG_IPV6 */
262 
263 
264 /* This is our APPLICATION-SPECIFIC state cookie.
265  * THIS IS NOT DICTATED BY THE SPECIFICATION.
266  */
267 /* These are the parts of an association which we send in the cookie.
268  * Most of these are straight out of:
269  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
270  *
271  */
272 
273 struct sctp_cookie {
274 
275 	/* My	       : Tag expected in every inbound packet and sent
276 	 * Verification: in the INIT or INIT ACK chunk.
277 	 * Tag	       :
278 	 */
279 	__u32 my_vtag;
280 
281 	/* Peer's      : Tag expected in every outbound packet except
282 	 * Verification: in the INIT chunk.
283 	 * Tag	       :
284 	 */
285 	__u32 peer_vtag;
286 
287 	/* The rest of these are not from the spec, but really need to
288 	 * be in the cookie.
289 	 */
290 
291 	/* My Tie Tag  : Assist in discovering a restarting association. */
292 	__u32 my_ttag;
293 
294 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
295 	__u32 peer_ttag;
296 
297 	/* When does this cookie expire? */
298 	ktime_t expiration;
299 
300 	/* Number of inbound/outbound streams which are set
301 	 * and negotiated during the INIT process.
302 	 */
303 	__u16 sinit_num_ostreams;
304 	__u16 sinit_max_instreams;
305 
306 	/* This is the first sequence number I used.  */
307 	__u32 initial_tsn;
308 
309 	/* This holds the originating address of the INIT packet.  */
310 	union sctp_addr peer_addr;
311 
312 	/* IG Section 2.35.3
313 	 * Include the source port of the INIT-ACK
314 	 */
315 	__u16		my_port;
316 
317 	__u8 prsctp_capable;
318 
319 	/* Padding for future use */
320 	__u8 padding;
321 
322 	__u32 adaptation_ind;
323 
324 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
325 			 SCTP_AUTH_RANDOM_LENGTH];
326 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
327 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
328 
329 	/* This is a shim for my peer's INIT packet, followed by
330 	 * a copy of the raw address list of the association.
331 	 * The length of the raw address list is saved in the
332 	 * raw_addr_list_len field, which will be used at the time when
333 	 * the association TCB is re-constructed from the cookie.
334 	 */
335 	__u32 raw_addr_list_len;
336 	struct sctp_init_chunk peer_init[0];
337 };
338 
339 
340 /* The format of our cookie that we send to our peer. */
341 struct sctp_signed_cookie {
342 	__u8 signature[SCTP_SECRET_SIZE];
343 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
344 	struct sctp_cookie c;
345 } __packed;
346 
347 /* This is another convenience type to allocate memory for address
348  * params for the maximum size and pass such structures around
349  * internally.
350  */
351 union sctp_addr_param {
352 	struct sctp_paramhdr p;
353 	struct sctp_ipv4addr_param v4;
354 	struct sctp_ipv6addr_param v6;
355 };
356 
357 /* A convenience type to allow walking through the various
358  * parameters and avoid casting all over the place.
359  */
360 union sctp_params {
361 	void *v;
362 	struct sctp_paramhdr *p;
363 	struct sctp_cookie_preserve_param *life;
364 	struct sctp_hostname_param *dns;
365 	struct sctp_cookie_param *cookie;
366 	struct sctp_supported_addrs_param *sat;
367 	struct sctp_ipv4addr_param *v4;
368 	struct sctp_ipv6addr_param *v6;
369 	union sctp_addr_param *addr;
370 	struct sctp_adaptation_ind_param *aind;
371 	struct sctp_supported_ext_param *ext;
372 	struct sctp_random_param *random;
373 	struct sctp_chunks_param *chunks;
374 	struct sctp_hmac_algo_param *hmac_algo;
375 	struct sctp_addip_param *addip;
376 };
377 
378 /* RFC 2960.  Section 3.3.5 Heartbeat.
379  *    Heartbeat Information: variable length
380  *    The Sender-specific Heartbeat Info field should normally include
381  *    information about the sender's current time when this HEARTBEAT
382  *    chunk is sent and the destination transport address to which this
383  *    HEARTBEAT is sent (see Section 8.3).
384  */
385 struct sctp_sender_hb_info {
386 	struct sctp_paramhdr param_hdr;
387 	union sctp_addr daddr;
388 	unsigned long sent_at;
389 	__u64 hb_nonce;
390 };
391 
392 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
393 		     gfp_t gfp);
394 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
395 void sctp_stream_free(struct sctp_stream *stream);
396 void sctp_stream_clear(struct sctp_stream *stream);
397 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
398 
399 /* What is the current SSN number for this stream? */
400 #define sctp_ssn_peek(stream, type, sid) \
401 	((stream)->type[sid].ssn)
402 
403 /* Return the next SSN number for this stream.	*/
404 #define sctp_ssn_next(stream, type, sid) \
405 	((stream)->type[sid].ssn++)
406 
407 /* Skip over this ssn and all below. */
408 #define sctp_ssn_skip(stream, type, sid, ssn) \
409 	((stream)->type[sid].ssn = ssn + 1)
410 
411 /* What is the current MID number for this stream? */
412 #define sctp_mid_peek(stream, type, sid) \
413 	((stream)->type[sid].mid)
414 
415 /* Return the next MID number for this stream.  */
416 #define sctp_mid_next(stream, type, sid) \
417 	((stream)->type[sid].mid++)
418 
419 /* Skip over this mid and all below. */
420 #define sctp_mid_skip(stream, type, sid, mid) \
421 	((stream)->type[sid].mid = mid + 1)
422 
423 #define sctp_stream_in(asoc, sid) (&(asoc)->stream.in[sid])
424 
425 /* What is the current MID_uo number for this stream? */
426 #define sctp_mid_uo_peek(stream, type, sid) \
427 	((stream)->type[sid].mid_uo)
428 
429 /* Return the next MID_uo number for this stream.  */
430 #define sctp_mid_uo_next(stream, type, sid) \
431 	((stream)->type[sid].mid_uo++)
432 
433 /*
434  * Pointers to address related SCTP functions.
435  * (i.e. things that depend on the address family.)
436  */
437 struct sctp_af {
438 	int		(*sctp_xmit)	(struct sk_buff *skb,
439 					 struct sctp_transport *);
440 	int		(*setsockopt)	(struct sock *sk,
441 					 int level,
442 					 int optname,
443 					 char __user *optval,
444 					 unsigned int optlen);
445 	int		(*getsockopt)	(struct sock *sk,
446 					 int level,
447 					 int optname,
448 					 char __user *optval,
449 					 int __user *optlen);
450 	int		(*compat_setsockopt)	(struct sock *sk,
451 					 int level,
452 					 int optname,
453 					 char __user *optval,
454 					 unsigned int optlen);
455 	int		(*compat_getsockopt)	(struct sock *sk,
456 					 int level,
457 					 int optname,
458 					 char __user *optval,
459 					 int __user *optlen);
460 	void		(*get_dst)	(struct sctp_transport *t,
461 					 union sctp_addr *saddr,
462 					 struct flowi *fl,
463 					 struct sock *sk);
464 	void		(*get_saddr)	(struct sctp_sock *sk,
465 					 struct sctp_transport *t,
466 					 struct flowi *fl);
467 	void		(*copy_addrlist) (struct list_head *,
468 					  struct net_device *);
469 	int		(*cmp_addr)	(const union sctp_addr *addr1,
470 					 const union sctp_addr *addr2);
471 	void		(*addr_copy)	(union sctp_addr *dst,
472 					 union sctp_addr *src);
473 	void		(*from_skb)	(union sctp_addr *,
474 					 struct sk_buff *skb,
475 					 int saddr);
476 	void		(*from_sk)	(union sctp_addr *,
477 					 struct sock *sk);
478 	void		(*from_addr_param) (union sctp_addr *,
479 					    union sctp_addr_param *,
480 					    __be16 port, int iif);
481 	int		(*to_addr_param) (const union sctp_addr *,
482 					  union sctp_addr_param *);
483 	int		(*addr_valid)	(union sctp_addr *,
484 					 struct sctp_sock *,
485 					 const struct sk_buff *);
486 	enum sctp_scope	(*scope)(union sctp_addr *);
487 	void		(*inaddr_any)	(union sctp_addr *, __be16);
488 	int		(*is_any)	(const union sctp_addr *);
489 	int		(*available)	(union sctp_addr *,
490 					 struct sctp_sock *);
491 	int		(*skb_iif)	(const struct sk_buff *sk);
492 	int		(*is_ce)	(const struct sk_buff *sk);
493 	void		(*seq_dump_addr)(struct seq_file *seq,
494 					 union sctp_addr *addr);
495 	void		(*ecn_capable)(struct sock *sk);
496 	__u16		net_header_len;
497 	int		sockaddr_len;
498 	int		(*ip_options_len)(struct sock *sk);
499 	sa_family_t	sa_family;
500 	struct list_head list;
501 };
502 
503 struct sctp_af *sctp_get_af_specific(sa_family_t);
504 int sctp_register_af(struct sctp_af *);
505 
506 /* Protocol family functions. */
507 struct sctp_pf {
508 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
509 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
510 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
511 	int  (*cmp_addr) (const union sctp_addr *,
512 			  const union sctp_addr *,
513 			  struct sctp_sock *);
514 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
515 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
516 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
517 	struct sock *(*create_accept_sk) (struct sock *sk,
518 					  struct sctp_association *asoc,
519 					  bool kern);
520 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
521 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
522 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
523 	void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
524 	struct sctp_af *af;
525 };
526 
527 
528 /* Structure to track chunk fragments that have been acked, but peer
529  * fragments of the same message have not.
530  */
531 struct sctp_datamsg {
532 	/* Chunks waiting to be submitted to lower layer. */
533 	struct list_head chunks;
534 	/* Reference counting. */
535 	refcount_t refcnt;
536 	/* When is this message no longer interesting to the peer? */
537 	unsigned long expires_at;
538 	/* Did the messenge fail to send? */
539 	int send_error;
540 	u8 send_failed:1,
541 	   can_delay:1,	/* should this message be Nagle delayed */
542 	   abandoned:1;	/* should this message be abandoned */
543 };
544 
545 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
546 					    struct sctp_sndrcvinfo *,
547 					    struct iov_iter *);
548 void sctp_datamsg_free(struct sctp_datamsg *);
549 void sctp_datamsg_put(struct sctp_datamsg *);
550 void sctp_chunk_fail(struct sctp_chunk *, int error);
551 int sctp_chunk_abandoned(struct sctp_chunk *);
552 
553 /* RFC2960 1.4 Key Terms
554  *
555  * o Chunk: A unit of information within an SCTP packet, consisting of
556  * a chunk header and chunk-specific content.
557  *
558  * As a matter of convenience, we remember the SCTP common header for
559  * each chunk as well as a few other header pointers...
560  */
561 struct sctp_chunk {
562 	struct list_head list;
563 
564 	refcount_t refcnt;
565 
566 	/* How many times this chunk have been sent, for prsctp RTX policy */
567 	int sent_count;
568 
569 	union {
570 		/* This is our link to the per-transport transmitted list.  */
571 		struct list_head transmitted_list;
572 		/* List in specific stream outq */
573 		struct list_head stream_list;
574 	};
575 
576 	/* This field is used by chunks that hold fragmented data.
577 	 * For the first fragment this is the list that holds the rest of
578 	 * fragments. For the remaining fragments, this is the link to the
579 	 * frag_list maintained in the first fragment.
580 	 */
581 	struct list_head frag_list;
582 
583 	/* This points to the sk_buff containing the actual data.  */
584 	struct sk_buff *skb;
585 
586 	union {
587 		/* In case of GSO packets, this will store the head one */
588 		struct sk_buff *head_skb;
589 		/* In case of auth enabled, this will point to the shkey */
590 		struct sctp_shared_key *shkey;
591 	};
592 
593 	/* These are the SCTP headers by reverse order in a packet.
594 	 * Note that some of these may happen more than once.  In that
595 	 * case, we point at the "current" one, whatever that means
596 	 * for that level of header.
597 	 */
598 
599 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
600 	union sctp_params param_hdr;
601 	union {
602 		__u8 *v;
603 		struct sctp_datahdr *data_hdr;
604 		struct sctp_inithdr *init_hdr;
605 		struct sctp_sackhdr *sack_hdr;
606 		struct sctp_heartbeathdr *hb_hdr;
607 		struct sctp_sender_hb_info *hbs_hdr;
608 		struct sctp_shutdownhdr *shutdown_hdr;
609 		struct sctp_signed_cookie *cookie_hdr;
610 		struct sctp_ecnehdr *ecne_hdr;
611 		struct sctp_cwrhdr *ecn_cwr_hdr;
612 		struct sctp_errhdr *err_hdr;
613 		struct sctp_addiphdr *addip_hdr;
614 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
615 		struct sctp_authhdr *auth_hdr;
616 		struct sctp_idatahdr *idata_hdr;
617 		struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
618 	} subh;
619 
620 	__u8 *chunk_end;
621 
622 	struct sctp_chunkhdr *chunk_hdr;
623 	struct sctphdr *sctp_hdr;
624 
625 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
626 	struct sctp_sndrcvinfo sinfo;
627 
628 	/* Which association does this belong to?  */
629 	struct sctp_association *asoc;
630 
631 	/* What endpoint received this chunk? */
632 	struct sctp_ep_common *rcvr;
633 
634 	/* We fill this in if we are calculating RTT. */
635 	unsigned long sent_at;
636 
637 	/* What is the origin IP address for this chunk?  */
638 	union sctp_addr source;
639 	/* Destination address for this chunk. */
640 	union sctp_addr dest;
641 
642 	/* For outbound message, track all fragments for SEND_FAILED. */
643 	struct sctp_datamsg *msg;
644 
645 	/* For an inbound chunk, this tells us where it came from.
646 	 * For an outbound chunk, it tells us where we'd like it to
647 	 * go.	It is NULL if we have no preference.
648 	 */
649 	struct sctp_transport *transport;
650 
651 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
652 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
653 	 * spec violates the principle premis that all chunks are processed
654 	 * in order.
655 	 */
656 	struct sk_buff *auth_chunk;
657 
658 #define SCTP_CAN_FRTX 0x0
659 #define SCTP_NEED_FRTX 0x1
660 #define SCTP_DONT_FRTX 0x2
661 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
662 		has_tsn:1,		/* Does this chunk have a TSN yet? */
663 		has_ssn:1,		/* Does this chunk have a SSN yet? */
664 #define has_mid has_ssn
665 		singleton:1,		/* Only chunk in the packet? */
666 		end_of_packet:1,	/* Last chunk in the packet? */
667 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
668 		pdiscard:1,		/* Discard the whole packet now? */
669 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
670 		data_accepted:1,	/* At least 1 chunk accepted */
671 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
672 		has_asconf:1,		/* IN: have seen an asconf before */
673 		tsn_missing_report:2,	/* Data chunk missing counter. */
674 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
675 };
676 
677 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
678 void sctp_chunk_hold(struct sctp_chunk *);
679 void sctp_chunk_put(struct sctp_chunk *);
680 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
681 			  struct iov_iter *from);
682 void sctp_chunk_free(struct sctp_chunk *);
683 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
684 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
685 				 const struct sctp_association *,
686 				 struct sock *, gfp_t gfp);
687 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
688 		     union sctp_addr *);
689 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
690 
691 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
692 {
693 	return ntohs(ch->subh.data_hdr->stream);
694 }
695 
696 enum {
697 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
698 	SCTP_ADDR_SRC,		/* address can be used as source */
699 	SCTP_ADDR_DEL,		/* address about to be deleted */
700 };
701 
702 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
703 struct sctp_sockaddr_entry {
704 	struct list_head list;
705 	struct rcu_head	rcu;
706 	union sctp_addr a;
707 	__u8 state;
708 	__u8 valid;
709 };
710 
711 #define SCTP_ADDRESS_TICK_DELAY	500
712 
713 /* This structure holds lists of chunks as we are assembling for
714  * transmission.
715  */
716 struct sctp_packet {
717 	/* These are the SCTP header values (host order) for the packet. */
718 	__u16 source_port;
719 	__u16 destination_port;
720 	__u32 vtag;
721 
722 	/* This contains the payload chunks.  */
723 	struct list_head chunk_list;
724 
725 	/* This is the overhead of the sctp and ip headers. */
726 	size_t overhead;
727 	/* This is the total size of all chunks INCLUDING padding.  */
728 	size_t size;
729 	/* This is the maximum size this packet may have */
730 	size_t max_size;
731 
732 	/* The packet is destined for this transport address.
733 	 * The function we finally use to pass down to the next lower
734 	 * layer lives in the transport structure.
735 	 */
736 	struct sctp_transport *transport;
737 
738 	/* pointer to the auth chunk for this packet */
739 	struct sctp_chunk *auth;
740 
741 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
742 	    has_sack:1,		/* This packet contains a SACK chunk. */
743 	    has_auth:1,		/* This packet contains an AUTH chunk */
744 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
745 	    ipfragok:1;		/* So let ip fragment this packet */
746 };
747 
748 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
749 		      __u16 sport, __u16 dport);
750 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
751 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
752 					  struct sctp_chunk *chunk,
753 					  int one_packet, gfp_t gfp);
754 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
755 					struct sctp_chunk *chunk);
756 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
757 void sctp_packet_free(struct sctp_packet *);
758 
759 static inline int sctp_packet_empty(struct sctp_packet *packet)
760 {
761 	return packet->size == packet->overhead;
762 }
763 
764 /* This represents a remote transport address.
765  * For local transport addresses, we just use union sctp_addr.
766  *
767  * RFC2960 Section 1.4 Key Terms
768  *
769  *   o	Transport address:  A Transport Address is traditionally defined
770  *	by Network Layer address, Transport Layer protocol and Transport
771  *	Layer port number.  In the case of SCTP running over IP, a
772  *	transport address is defined by the combination of an IP address
773  *	and an SCTP port number (where SCTP is the Transport protocol).
774  *
775  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
776  *
777  *   o	The sender keeps a separate congestion control parameter set for
778  *	each of the destination addresses it can send to (not each
779  *	source-destination pair but for each destination).  The parameters
780  *	should decay if the address is not used for a long enough time
781  *	period.
782  *
783  */
784 struct sctp_transport {
785 	/* A list of transports. */
786 	struct list_head transports;
787 	struct rhlist_head node;
788 
789 	/* Reference counting. */
790 	refcount_t refcnt;
791 		/* RTO-Pending : A flag used to track if one of the DATA
792 		 *		chunks sent to this address is currently being
793 		 *		used to compute a RTT. If this flag is 0,
794 		 *		the next DATA chunk sent to this destination
795 		 *		should be used to compute a RTT and this flag
796 		 *		should be set. Every time the RTT
797 		 *		calculation completes (i.e. the DATA chunk
798 		 *		is SACK'd) clear this flag.
799 		 */
800 	__u32	rto_pending:1,
801 
802 		/*
803 		 * hb_sent : a flag that signals that we have a pending
804 		 * heartbeat.
805 		 */
806 		hb_sent:1,
807 
808 		/* Is the Path MTU update pending on this tranport */
809 		pmtu_pending:1,
810 
811 		dst_pending_confirm:1,	/* need to confirm neighbour */
812 
813 		/* Has this transport moved the ctsn since we last sacked */
814 		sack_generation:1;
815 	u32 dst_cookie;
816 
817 	struct flowi fl;
818 
819 	/* This is the peer's IP address and port. */
820 	union sctp_addr ipaddr;
821 
822 	/* These are the functions we call to handle LLP stuff.	 */
823 	struct sctp_af *af_specific;
824 
825 	/* Which association do we belong to?  */
826 	struct sctp_association *asoc;
827 
828 	/* RFC2960
829 	 *
830 	 * 12.3 Per Transport Address Data
831 	 *
832 	 * For each destination transport address in the peer's
833 	 * address list derived from the INIT or INIT ACK chunk, a
834 	 * number of data elements needs to be maintained including:
835 	 */
836 	/* RTO	       : The current retransmission timeout value.  */
837 	unsigned long rto;
838 
839 	__u32 rtt;		/* This is the most recent RTT.	 */
840 
841 	/* RTTVAR      : The current RTT variation.  */
842 	__u32 rttvar;
843 
844 	/* SRTT	       : The current smoothed round trip time.	*/
845 	__u32 srtt;
846 
847 	/*
848 	 * These are the congestion stats.
849 	 */
850 	/* cwnd	       : The current congestion window.	 */
851 	__u32 cwnd;		  /* This is the actual cwnd.  */
852 
853 	/* ssthresh    : The current slow start threshold value.  */
854 	__u32 ssthresh;
855 
856 	/* partial     : The tracking method for increase of cwnd when in
857 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
858 	 */
859 	__u32 partial_bytes_acked;
860 
861 	/* Data that has been sent, but not acknowledged. */
862 	__u32 flight_size;
863 
864 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
865 
866 	/* Destination */
867 	struct dst_entry *dst;
868 	/* Source address. */
869 	union sctp_addr saddr;
870 
871 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
872 	 * the destination address every heartbeat interval.
873 	 */
874 	unsigned long hbinterval;
875 
876 	/* SACK delay timeout */
877 	unsigned long sackdelay;
878 	__u32 sackfreq;
879 
880 	/* When was the last time that we heard from this transport? We use
881 	 * this to pick new active and retran paths.
882 	 */
883 	ktime_t last_time_heard;
884 
885 	/* When was the last time that we sent a chunk using this
886 	 * transport? We use this to check for idle transports
887 	 */
888 	unsigned long last_time_sent;
889 
890 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
891 	 * indication based on ECNE chunk.
892 	 */
893 	unsigned long last_time_ecne_reduced;
894 
895 	/* This is the max_retrans value for the transport and will
896 	 * be initialized from the assocs value.  This can be changed
897 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
898 	 */
899 	__u16 pathmaxrxt;
900 
901 	__u32 flowlabel;
902 	__u8  dscp;
903 
904 	/* This is the partially failed retrans value for the transport
905 	 * and will be initialized from the assocs value.  This can be changed
906 	 * using the SCTP_PEER_ADDR_THLDS socket option
907 	 */
908 	int pf_retrans;
909 	/* PMTU	      : The current known path MTU.  */
910 	__u32 pathmtu;
911 
912 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
913 	__u32 param_flags;
914 
915 	/* The number of times INIT has been sent on this transport. */
916 	int init_sent_count;
917 
918 	/* state       : The current state of this destination,
919 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
920 	 */
921 	int state;
922 
923 	/* These are the error stats for this destination.  */
924 
925 	/* Error count : The current error count for this destination.	*/
926 	unsigned short error_count;
927 
928 	/* Per	       : A timer used by each destination.
929 	 * Destination :
930 	 * Timer       :
931 	 *
932 	 * [Everywhere else in the text this is called T3-rtx. -ed]
933 	 */
934 	struct timer_list T3_rtx_timer;
935 
936 	/* Heartbeat timer is per destination. */
937 	struct timer_list hb_timer;
938 
939 	/* Timer to handle ICMP proto unreachable envets */
940 	struct timer_list proto_unreach_timer;
941 
942 	/* Timer to handler reconf chunk rtx */
943 	struct timer_list reconf_timer;
944 
945 	/* Since we're using per-destination retransmission timers
946 	 * (see above), we're also using per-destination "transmitted"
947 	 * queues.  This probably ought to be a private struct
948 	 * accessible only within the outqueue, but it's not, yet.
949 	 */
950 	struct list_head transmitted;
951 
952 	/* We build bundle-able packets for this transport here.  */
953 	struct sctp_packet packet;
954 
955 	/* This is the list of transports that have chunks to send.  */
956 	struct list_head send_ready;
957 
958 	/* State information saved for SFR_CACC algorithm. The key
959 	 * idea in SFR_CACC is to maintain state at the sender on a
960 	 * per-destination basis when a changeover happens.
961 	 *	char changeover_active;
962 	 *	char cycling_changeover;
963 	 *	__u32 next_tsn_at_change;
964 	 *	char cacc_saw_newack;
965 	 */
966 	struct {
967 		/* An unsigned integer, which stores the next TSN to be
968 		 * used by the sender, at the moment of changeover.
969 		 */
970 		__u32 next_tsn_at_change;
971 
972 		/* A flag which indicates the occurrence of a changeover */
973 		char changeover_active;
974 
975 		/* A flag which indicates whether the change of primary is
976 		 * the first switch to this destination address during an
977 		 * active switch.
978 		 */
979 		char cycling_changeover;
980 
981 		/* A temporary flag, which is used during the processing of
982 		 * a SACK to estimate the causative TSN(s)'s group.
983 		 */
984 		char cacc_saw_newack;
985 	} cacc;
986 
987 	/* 64-bit random number sent with heartbeat. */
988 	__u64 hb_nonce;
989 
990 	struct rcu_head rcu;
991 };
992 
993 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
994 					  gfp_t);
995 void sctp_transport_set_owner(struct sctp_transport *,
996 			      struct sctp_association *);
997 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
998 			  struct sctp_sock *);
999 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
1000 void sctp_transport_free(struct sctp_transport *);
1001 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
1002 void sctp_transport_reset_hb_timer(struct sctp_transport *);
1003 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
1004 int sctp_transport_hold(struct sctp_transport *);
1005 void sctp_transport_put(struct sctp_transport *);
1006 void sctp_transport_update_rto(struct sctp_transport *, __u32);
1007 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1008 void sctp_transport_lower_cwnd(struct sctp_transport *t,
1009 			       enum sctp_lower_cwnd reason);
1010 void sctp_transport_burst_limited(struct sctp_transport *);
1011 void sctp_transport_burst_reset(struct sctp_transport *);
1012 unsigned long sctp_transport_timeout(struct sctp_transport *);
1013 void sctp_transport_reset(struct sctp_transport *t);
1014 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1015 void sctp_transport_immediate_rtx(struct sctp_transport *);
1016 void sctp_transport_dst_release(struct sctp_transport *t);
1017 void sctp_transport_dst_confirm(struct sctp_transport *t);
1018 
1019 
1020 /* This is the structure we use to queue packets as they come into
1021  * SCTP.  We write packets to it and read chunks from it.
1022  */
1023 struct sctp_inq {
1024 	/* This is actually a queue of sctp_chunk each
1025 	 * containing a partially decoded packet.
1026 	 */
1027 	struct list_head in_chunk_list;
1028 	/* This is the packet which is currently off the in queue and is
1029 	 * being worked on through the inbound chunk processing.
1030 	 */
1031 	struct sctp_chunk *in_progress;
1032 
1033 	/* This is the delayed task to finish delivering inbound
1034 	 * messages.
1035 	 */
1036 	struct work_struct immediate;
1037 };
1038 
1039 void sctp_inq_init(struct sctp_inq *);
1040 void sctp_inq_free(struct sctp_inq *);
1041 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1042 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1043 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1044 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1045 
1046 /* This is the structure we use to hold outbound chunks.  You push
1047  * chunks in and they automatically pop out the other end as bundled
1048  * packets (it calls (*output_handler)()).
1049  *
1050  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1051  * and 8.2 of the v13 draft.
1052  *
1053  * It handles retransmissions.	The connection to the timeout portion
1054  * of the state machine is through sctp_..._timeout() and timeout_handler.
1055  *
1056  * If you feed it SACKs, it will eat them.
1057  *
1058  * If you give it big chunks, it will fragment them.
1059  *
1060  * It assigns TSN's to data chunks.  This happens at the last possible
1061  * instant before transmission.
1062  *
1063  * When free()'d, it empties itself out via output_handler().
1064  */
1065 struct sctp_outq {
1066 	struct sctp_association *asoc;
1067 
1068 	/* Data pending that has never been transmitted.  */
1069 	struct list_head out_chunk_list;
1070 
1071 	/* Stream scheduler being used */
1072 	struct sctp_sched_ops *sched;
1073 
1074 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1075 
1076 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1077 	unsigned int error;
1078 
1079 	/* These are control chunks we want to send.  */
1080 	struct list_head control_chunk_list;
1081 
1082 	/* These are chunks that have been sacked but are above the
1083 	 * CTSN, or cumulative tsn ack point.
1084 	 */
1085 	struct list_head sacked;
1086 
1087 	/* Put chunks on this list to schedule them for
1088 	 * retransmission.
1089 	 */
1090 	struct list_head retransmit;
1091 
1092 	/* Put chunks on this list to save them for FWD TSN processing as
1093 	 * they were abandoned.
1094 	 */
1095 	struct list_head abandoned;
1096 
1097 	/* How many unackd bytes do we have in-flight?	*/
1098 	__u32 outstanding_bytes;
1099 
1100 	/* Are we doing fast-rtx on this queue */
1101 	char fast_rtx;
1102 
1103 	/* Corked? */
1104 	char cork;
1105 };
1106 
1107 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1108 void sctp_outq_teardown(struct sctp_outq *);
1109 void sctp_outq_free(struct sctp_outq*);
1110 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1111 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1112 int sctp_outq_is_empty(const struct sctp_outq *);
1113 void sctp_outq_restart(struct sctp_outq *);
1114 
1115 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1116 		     enum sctp_retransmit_reason reason);
1117 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1118 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1119 void sctp_prsctp_prune(struct sctp_association *asoc,
1120 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1121 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1122 /* Uncork and flush an outqueue.  */
1123 static inline void sctp_outq_cork(struct sctp_outq *q)
1124 {
1125 	q->cork = 1;
1126 }
1127 
1128 /* SCTP skb control block.
1129  * sctp_input_cb is currently used on rx and sock rx queue
1130  */
1131 struct sctp_input_cb {
1132 	union {
1133 		struct inet_skb_parm	h4;
1134 #if IS_ENABLED(CONFIG_IPV6)
1135 		struct inet6_skb_parm	h6;
1136 #endif
1137 	} header;
1138 	struct sctp_chunk *chunk;
1139 	struct sctp_af *af;
1140 };
1141 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1142 
1143 struct sctp_output_cb {
1144 	struct sk_buff *last;
1145 };
1146 #define SCTP_OUTPUT_CB(__skb)	((struct sctp_output_cb *)&((__skb)->cb[0]))
1147 
1148 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1149 {
1150 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1151 
1152 	return chunk->head_skb ? : skb;
1153 }
1154 
1155 /* These bind address data fields common between endpoints and associations */
1156 struct sctp_bind_addr {
1157 
1158 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1159 	 *
1160 	 * SCTP Port:	The local SCTP port number the endpoint is
1161 	 *		bound to.
1162 	 */
1163 	__u16 port;
1164 
1165 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1166 	 *
1167 	 * Address List: The list of IP addresses that this instance
1168 	 *	has bound.  This information is passed to one's
1169 	 *	peer(s) in INIT and INIT ACK chunks.
1170 	 */
1171 	struct list_head address_list;
1172 };
1173 
1174 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1175 void sctp_bind_addr_free(struct sctp_bind_addr *);
1176 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1177 			const struct sctp_bind_addr *src,
1178 			enum sctp_scope scope, gfp_t gfp,
1179 			int flags);
1180 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1181 			const struct sctp_bind_addr *src,
1182 			gfp_t gfp);
1183 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1184 		       int new_size, __u8 addr_state, gfp_t gfp);
1185 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1186 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1187 			 struct sctp_sock *);
1188 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1189 			 struct sctp_sock *, struct sctp_sock *);
1190 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1191 			 const union sctp_addr *addr);
1192 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1193 					const union sctp_addr	*addrs,
1194 					int			addrcnt,
1195 					struct sctp_sock	*opt);
1196 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1197 					 int *addrs_len,
1198 					 gfp_t gfp);
1199 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1200 			   __u16 port, gfp_t gfp);
1201 
1202 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1203 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1204 		  const enum sctp_scope scope);
1205 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1206 int sctp_is_ep_boundall(struct sock *sk);
1207 
1208 
1209 /* What type of endpoint?  */
1210 enum sctp_endpoint_type {
1211 	SCTP_EP_TYPE_SOCKET,
1212 	SCTP_EP_TYPE_ASSOCIATION,
1213 };
1214 
1215 /*
1216  * A common base class to bridge the implmentation view of a
1217  * socket (usually listening) endpoint versus an association's
1218  * local endpoint.
1219  * This common structure is useful for several purposes:
1220  *   1) Common interface for lookup routines.
1221  *	a) Subfunctions work for either endpoint or association
1222  *	b) Single interface to lookup allows hiding the lookup lock rather
1223  *	   than acquiring it externally.
1224  *   2) Common interface for the inbound chunk handling/state machine.
1225  *   3) Common object handling routines for reference counting, etc.
1226  *   4) Disentangle association lookup from endpoint lookup, where we
1227  *	do not have to find our endpoint to find our association.
1228  *
1229  */
1230 
1231 struct sctp_ep_common {
1232 	/* Fields to help us manage our entries in the hash tables. */
1233 	struct hlist_node node;
1234 	int hashent;
1235 
1236 	/* Runtime type information.  What kind of endpoint is this? */
1237 	enum sctp_endpoint_type type;
1238 
1239 	/* Some fields to help us manage this object.
1240 	 *   refcnt   - Reference count access to this object.
1241 	 *   dead     - Do not attempt to use this object.
1242 	 */
1243 	refcount_t    refcnt;
1244 	bool	    dead;
1245 
1246 	/* What socket does this endpoint belong to?  */
1247 	struct sock *sk;
1248 
1249 	/* This is where we receive inbound chunks.  */
1250 	struct sctp_inq	  inqueue;
1251 
1252 	/* This substructure includes the defining parameters of the
1253 	 * endpoint:
1254 	 * bind_addr.port is our shared port number.
1255 	 * bind_addr.address_list is our set of local IP addresses.
1256 	 */
1257 	struct sctp_bind_addr bind_addr;
1258 };
1259 
1260 
1261 /* RFC Section 1.4 Key Terms
1262  *
1263  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1264  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1265  *   combination of a set of eligible destination transport addresses to
1266  *   which SCTP packets can be sent and a set of eligible source
1267  *   transport addresses from which SCTP packets can be received.
1268  *   All transport addresses used by an SCTP endpoint must use the
1269  *   same port number, but can use multiple IP addresses. A transport
1270  *   address used by an SCTP endpoint must not be used by another
1271  *   SCTP endpoint. In other words, a transport address is unique
1272  *   to an SCTP endpoint.
1273  *
1274  * From an implementation perspective, each socket has one of these.
1275  * A TCP-style socket will have exactly one association on one of
1276  * these.  An UDP-style socket will have multiple associations hanging
1277  * off one of these.
1278  */
1279 
1280 struct sctp_endpoint {
1281 	/* Common substructure for endpoint and association. */
1282 	struct sctp_ep_common base;
1283 
1284 	/* Associations: A list of current associations and mappings
1285 	 *	      to the data consumers for each association. This
1286 	 *	      may be in the form of a hash table or other
1287 	 *	      implementation dependent structure. The data
1288 	 *	      consumers may be process identification
1289 	 *	      information such as file descriptors, named pipe
1290 	 *	      pointer, or table pointers dependent on how SCTP
1291 	 *	      is implemented.
1292 	 */
1293 	/* This is really a list of struct sctp_association entries. */
1294 	struct list_head asocs;
1295 
1296 	/* Secret Key: A secret key used by this endpoint to compute
1297 	 *	      the MAC.	This SHOULD be a cryptographic quality
1298 	 *	      random number with a sufficient length.
1299 	 *	      Discussion in [RFC1750] can be helpful in
1300 	 *	      selection of the key.
1301 	 */
1302 	__u8 secret_key[SCTP_SECRET_SIZE];
1303 
1304  	/* digest:  This is a digest of the sctp cookie.  This field is
1305  	 * 	    only used on the receive path when we try to validate
1306  	 * 	    that the cookie has not been tampered with.  We put
1307  	 * 	    this here so we pre-allocate this once and can re-use
1308  	 * 	    on every receive.
1309  	 */
1310  	__u8 *digest;
1311 
1312 	/* sendbuf acct. policy.	*/
1313 	__u32 sndbuf_policy;
1314 
1315 	/* rcvbuf acct. policy.	*/
1316 	__u32 rcvbuf_policy;
1317 
1318 	/* SCTP AUTH: array of the HMACs that will be allocated
1319 	 * we need this per association so that we don't serialize
1320 	 */
1321 	struct crypto_shash **auth_hmacs;
1322 
1323 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1324 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1325 
1326 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1327 	struct sctp_chunks_param *auth_chunk_list;
1328 
1329 	/* SCTP-AUTH: endpoint shared keys */
1330 	struct list_head endpoint_shared_keys;
1331 	__u16 active_key_id;
1332 	__u8  auth_enable:1,
1333 	      prsctp_enable:1,
1334 	      reconf_enable:1;
1335 
1336 	__u8  strreset_enable;
1337 
1338 	/* Security identifiers from incoming (INIT). These are set by
1339 	 * security_sctp_assoc_request(). These will only be used by
1340 	 * SCTP TCP type sockets and peeled off connections as they
1341 	 * cause a new socket to be generated. security_sctp_sk_clone()
1342 	 * will then plug these into the new socket.
1343 	 */
1344 
1345 	u32 secid;
1346 	u32 peer_secid;
1347 };
1348 
1349 /* Recover the outter endpoint structure. */
1350 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1351 {
1352 	struct sctp_endpoint *ep;
1353 
1354 	ep = container_of(base, struct sctp_endpoint, base);
1355 	return ep;
1356 }
1357 
1358 /* These are function signatures for manipulating endpoints.  */
1359 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1360 void sctp_endpoint_free(struct sctp_endpoint *);
1361 void sctp_endpoint_put(struct sctp_endpoint *);
1362 void sctp_endpoint_hold(struct sctp_endpoint *);
1363 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1364 struct sctp_association *sctp_endpoint_lookup_assoc(
1365 	const struct sctp_endpoint *ep,
1366 	const union sctp_addr *paddr,
1367 	struct sctp_transport **);
1368 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1369 				 const union sctp_addr *paddr);
1370 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1371 					struct net *, const union sctp_addr *);
1372 bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1373 			  const union sctp_addr *paddr);
1374 
1375 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1376 		     const struct sctp_association *asoc,
1377 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1378 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1379 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1380 		      const union sctp_addr *peer,
1381 		      struct sctp_init_chunk *init, gfp_t gfp);
1382 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1383 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1384 
1385 struct sctp_inithdr_host {
1386 	__u32 init_tag;
1387 	__u32 a_rwnd;
1388 	__u16 num_outbound_streams;
1389 	__u16 num_inbound_streams;
1390 	__u32 initial_tsn;
1391 };
1392 
1393 struct sctp_stream_priorities {
1394 	/* List of priorities scheduled */
1395 	struct list_head prio_sched;
1396 	/* List of streams scheduled */
1397 	struct list_head active;
1398 	/* The next stream stream in line */
1399 	struct sctp_stream_out_ext *next;
1400 	__u16 prio;
1401 };
1402 
1403 struct sctp_stream_out_ext {
1404 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1405 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1406 	struct list_head outq; /* chunks enqueued by this stream */
1407 	union {
1408 		struct {
1409 			/* Scheduled streams list */
1410 			struct list_head prio_list;
1411 			struct sctp_stream_priorities *prio_head;
1412 		};
1413 		/* Fields used by RR scheduler */
1414 		struct {
1415 			struct list_head rr_list;
1416 		};
1417 	};
1418 };
1419 
1420 struct sctp_stream_out {
1421 	union {
1422 		__u32 mid;
1423 		__u16 ssn;
1424 	};
1425 	__u32 mid_uo;
1426 	struct sctp_stream_out_ext *ext;
1427 	__u8 state;
1428 };
1429 
1430 struct sctp_stream_in {
1431 	union {
1432 		__u32 mid;
1433 		__u16 ssn;
1434 	};
1435 	__u32 mid_uo;
1436 	__u32 fsn;
1437 	__u32 fsn_uo;
1438 	char pd_mode;
1439 	char pd_mode_uo;
1440 };
1441 
1442 struct sctp_stream {
1443 	struct sctp_stream_out *out;
1444 	struct sctp_stream_in *in;
1445 	__u16 outcnt;
1446 	__u16 incnt;
1447 	/* Current stream being sent, if any */
1448 	struct sctp_stream_out *out_curr;
1449 	union {
1450 		/* Fields used by priority scheduler */
1451 		struct {
1452 			/* List of priorities scheduled */
1453 			struct list_head prio_list;
1454 		};
1455 		/* Fields used by RR scheduler */
1456 		struct {
1457 			/* List of streams scheduled */
1458 			struct list_head rr_list;
1459 			/* The next stream stream in line */
1460 			struct sctp_stream_out_ext *rr_next;
1461 		};
1462 	};
1463 	struct sctp_stream_interleave *si;
1464 };
1465 
1466 #define SCTP_STREAM_CLOSED		0x00
1467 #define SCTP_STREAM_OPEN		0x01
1468 
1469 static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1470 {
1471 	return stream->si->data_chunk_len;
1472 }
1473 
1474 static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1475 {
1476 	return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1477 }
1478 
1479 static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1480 {
1481 	return stream->si->ftsn_chunk_len;
1482 }
1483 
1484 static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1485 {
1486 	return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1487 }
1488 
1489 /* SCTP_GET_ASSOC_STATS counters */
1490 struct sctp_priv_assoc_stats {
1491 	/* Maximum observed rto in the association during subsequent
1492 	 * observations. Value is set to 0 if no RTO measurement took place
1493 	 * The transport where the max_rto was observed is returned in
1494 	 * obs_rto_ipaddr
1495 	 */
1496 	struct sockaddr_storage obs_rto_ipaddr;
1497 	__u64 max_obs_rto;
1498 	/* Total In and Out SACKs received and sent */
1499 	__u64 isacks;
1500 	__u64 osacks;
1501 	/* Total In and Out packets received and sent */
1502 	__u64 opackets;
1503 	__u64 ipackets;
1504 	/* Total retransmitted chunks */
1505 	__u64 rtxchunks;
1506 	/* TSN received > next expected */
1507 	__u64 outofseqtsns;
1508 	/* Duplicate Chunks received */
1509 	__u64 idupchunks;
1510 	/* Gap Ack Blocks received */
1511 	__u64 gapcnt;
1512 	/* Unordered data chunks sent and received */
1513 	__u64 ouodchunks;
1514 	__u64 iuodchunks;
1515 	/* Ordered data chunks sent and received */
1516 	__u64 oodchunks;
1517 	__u64 iodchunks;
1518 	/* Control chunks sent and received */
1519 	__u64 octrlchunks;
1520 	__u64 ictrlchunks;
1521 };
1522 
1523 /* RFC2960
1524  *
1525  * 12. Recommended Transmission Control Block (TCB) Parameters
1526  *
1527  * This section details a recommended set of parameters that should
1528  * be contained within the TCB for an implementation. This section is
1529  * for illustrative purposes and should not be deemed as requirements
1530  * on an implementation or as an exhaustive list of all parameters
1531  * inside an SCTP TCB. Each implementation may need its own additional
1532  * parameters for optimization.
1533  */
1534 
1535 
1536 /* Here we have information about each individual association. */
1537 struct sctp_association {
1538 
1539 	/* A base structure common to endpoint and association.
1540 	 * In this context, it represents the associations's view
1541 	 * of the local endpoint of the association.
1542 	 */
1543 	struct sctp_ep_common base;
1544 
1545 	/* Associations on the same socket. */
1546 	struct list_head asocs;
1547 
1548 	/* association id. */
1549 	sctp_assoc_t assoc_id;
1550 
1551 	/* This is our parent endpoint.	 */
1552 	struct sctp_endpoint *ep;
1553 
1554 	/* These are those association elements needed in the cookie.  */
1555 	struct sctp_cookie c;
1556 
1557 	/* This is all information about our peer.  */
1558 	struct {
1559 		/* transport_addr_list
1560 		 *
1561 		 * Peer	       : A list of SCTP transport addresses that the
1562 		 * Transport   : peer is bound to. This information is derived
1563 		 * Address     : from the INIT or INIT ACK and is used to
1564 		 * List	       : associate an inbound packet with a given
1565 		 *	       : association. Normally this information is
1566 		 *	       : hashed or keyed for quick lookup and access
1567 		 *	       : of the TCB.
1568 		 *	       : The list is also initialized with the list
1569 		 *	       : of addresses passed with the sctp_connectx()
1570 		 *	       : call.
1571 		 *
1572 		 * It is a list of SCTP_transport's.
1573 		 */
1574 		struct list_head transport_addr_list;
1575 
1576 		/* rwnd
1577 		 *
1578 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1579 		 */
1580 		__u32 rwnd;
1581 
1582 		/* transport_count
1583 		 *
1584 		 * Peer        : A count of the number of peer addresses
1585 		 * Transport   : in the Peer Transport Address List.
1586 		 * Address     :
1587 		 * Count       :
1588 		 */
1589 		__u16 transport_count;
1590 
1591 		/* port
1592 		 *   The transport layer port number.
1593 		 */
1594 		__u16 port;
1595 
1596 		/* primary_path
1597 		 *
1598 		 * Primary     : This is the current primary destination
1599 		 * Path	       : transport address of the peer endpoint.  It
1600 		 *	       : may also specify a source transport address
1601 		 *	       : on this endpoint.
1602 		 *
1603 		 * All of these paths live on transport_addr_list.
1604 		 *
1605 		 * At the bakeoffs, we discovered that the intent of
1606 		 * primaryPath is that it only changes when the ULP
1607 		 * asks to have it changed.  We add the activePath to
1608 		 * designate the connection we are currently using to
1609 		 * transmit new data and most control chunks.
1610 		 */
1611 		struct sctp_transport *primary_path;
1612 
1613 		/* Cache the primary path address here, when we
1614 		 * need a an address for msg_name.
1615 		 */
1616 		union sctp_addr primary_addr;
1617 
1618 		/* active_path
1619 		 *   The path that we are currently using to
1620 		 *   transmit new data and most control chunks.
1621 		 */
1622 		struct sctp_transport *active_path;
1623 
1624 		/* retran_path
1625 		 *
1626 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1627 		 * ...
1628 		 * Furthermore, when its peer is multi-homed, an
1629 		 * endpoint SHOULD try to retransmit a chunk to an
1630 		 * active destination transport address that is
1631 		 * different from the last destination address to
1632 		 * which the DATA chunk was sent.
1633 		 */
1634 		struct sctp_transport *retran_path;
1635 
1636 		/* Pointer to last transport I have sent on.  */
1637 		struct sctp_transport *last_sent_to;
1638 
1639 		/* This is the last transport I have received DATA on.	*/
1640 		struct sctp_transport *last_data_from;
1641 
1642 		/*
1643 		 * Mapping  An array of bits or bytes indicating which out of
1644 		 * Array    order TSN's have been received (relative to the
1645 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1646 		 *	    order packets have been received, this array
1647 		 *	    will be set to all zero. This structure may be
1648 		 *	    in the form of a circular buffer or bit array.
1649 		 *
1650 		 * Last Rcvd   : This is the last TSN received in
1651 		 * TSN	       : sequence. This value is set initially by
1652 		 *	       : taking the peer's Initial TSN, received in
1653 		 *	       : the INIT or INIT ACK chunk, and subtracting
1654 		 *	       : one from it.
1655 		 *
1656 		 * Throughout most of the specification this is called the
1657 		 * "Cumulative TSN ACK Point".	In this case, we
1658 		 * ignore the advice in 12.2 in favour of the term
1659 		 * used in the bulk of the text.  This value is hidden
1660 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1661 		 */
1662 		struct sctp_tsnmap tsn_map;
1663 
1664 		/* This mask is used to disable sending the ASCONF chunk
1665 		 * with specified parameter to peer.
1666 		 */
1667 		__be16 addip_disabled_mask;
1668 
1669 		/* These are capabilities which our peer advertised.  */
1670 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1671 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1672 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1673 			hostname_address:1, /* Peer understands DNS addresses? */
1674 			asconf_capable:1,   /* Does peer support ADDIP? */
1675 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1676 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1677 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1678 
1679 		/* sack_needed : This flag indicates if the next received
1680 		 *             : packet is to be responded to with a
1681 		 *             : SACK. This is initialized to 0.  When a packet
1682 		 *             : is received sack_cnt is incremented. If this value
1683 		 *             : reaches 2 or more, a SACK is sent and the
1684 		 *             : value is reset to 0. Note: This is used only
1685 		 *             : when no DATA chunks are received out of
1686 		 *             : order.  When DATA chunks are out of order,
1687 		 *             : SACK's are not delayed (see Section 6).
1688 		 */
1689 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1690 			sack_generation:1,
1691 			zero_window_announced:1;
1692 		__u32	sack_cnt;
1693 
1694 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1695 
1696 		struct sctp_inithdr_host i;
1697 		void *cookie;
1698 		int cookie_len;
1699 
1700 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1701 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1702 		 * Initial TSN Value minus 1
1703 		 */
1704 		__u32 addip_serial;
1705 
1706 		/* SCTP-AUTH: We need to know pears random number, hmac list
1707 		 * and authenticated chunk list.  All that is part of the
1708 		 * cookie and these are just pointers to those locations
1709 		 */
1710 		struct sctp_random_param *peer_random;
1711 		struct sctp_chunks_param *peer_chunks;
1712 		struct sctp_hmac_algo_param *peer_hmacs;
1713 	} peer;
1714 
1715 	/* State       : A state variable indicating what state the
1716 	 *	       : association is in, i.e. COOKIE-WAIT,
1717 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1718 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1719 	 *
1720 	 *		Note: No "CLOSED" state is illustrated since if a
1721 	 *		association is "CLOSED" its TCB SHOULD be removed.
1722 	 *
1723 	 *		In this implementation we DO have a CLOSED
1724 	 *		state which is used during initiation and shutdown.
1725 	 *
1726 	 *		State takes values from SCTP_STATE_*.
1727 	 */
1728 	enum sctp_state state;
1729 
1730 	/* Overall     : The overall association error count.
1731 	 * Error Count : [Clear this any time I get something.]
1732 	 */
1733 	int overall_error_count;
1734 
1735 	/* The cookie life I award for any cookie.  */
1736 	ktime_t cookie_life;
1737 
1738 	/* These are the association's initial, max, and min RTO values.
1739 	 * These values will be initialized by system defaults, but can
1740 	 * be modified via the SCTP_RTOINFO socket option.
1741 	 */
1742 	unsigned long rto_initial;
1743 	unsigned long rto_max;
1744 	unsigned long rto_min;
1745 
1746 	/* Maximum number of new data packets that can be sent in a burst.  */
1747 	int max_burst;
1748 
1749 	/* This is the max_retrans value for the association.  This value will
1750 	 * be initialized initialized from system defaults, but can be
1751 	 * modified by the SCTP_ASSOCINFO socket option.
1752 	 */
1753 	int max_retrans;
1754 
1755 	/* This is the partially failed retrans value for the transport
1756 	 * and will be initialized from the assocs value.  This can be
1757 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1758 	 */
1759 	int pf_retrans;
1760 
1761 	/* Maximum number of times the endpoint will retransmit INIT  */
1762 	__u16 max_init_attempts;
1763 
1764 	/* How many times have we resent an INIT? */
1765 	__u16 init_retries;
1766 
1767 	/* The largest timeout or RTO value to use in attempting an INIT */
1768 	unsigned long max_init_timeo;
1769 
1770 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1771 	 * the destination address every heartbeat interval. This value
1772 	 * will be inherited by all new transports.
1773 	 */
1774 	unsigned long hbinterval;
1775 
1776 	/* This is the max_retrans value for new transports in the
1777 	 * association.
1778 	 */
1779 	__u16 pathmaxrxt;
1780 
1781 	__u32 flowlabel;
1782 	__u8  dscp;
1783 
1784 	/* Flag that path mtu update is pending */
1785 	__u8   pmtu_pending;
1786 
1787 	/* Association : The smallest PMTU discovered for all of the
1788 	 * PMTU	       : peer's transport addresses.
1789 	 */
1790 	__u32 pathmtu;
1791 
1792 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1793 	__u32 param_flags;
1794 
1795 	__u32 sackfreq;
1796 	/* SACK delay timeout */
1797 	unsigned long sackdelay;
1798 
1799 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1800 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1801 
1802 	/* Transport to which SHUTDOWN chunk was last sent.  */
1803 	struct sctp_transport *shutdown_last_sent_to;
1804 
1805 	/* Transport to which INIT chunk was last sent.  */
1806 	struct sctp_transport *init_last_sent_to;
1807 
1808 	/* How many times have we resent a SHUTDOWN */
1809 	int shutdown_retries;
1810 
1811 	/* Next TSN    : The next TSN number to be assigned to a new
1812 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1813 	 *	       : ACK chunk to the peer and incremented each
1814 	 *	       : time a DATA chunk is assigned a TSN
1815 	 *	       : (normally just prior to transmit or during
1816 	 *	       : fragmentation).
1817 	 */
1818 	__u32 next_tsn;
1819 
1820 	/*
1821 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1822 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1823 	 *	       : received in the INIT or INIT ACK chunk, and
1824 	 *	       : subtracting one from it.
1825 	 *
1826 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1827 	 */
1828 
1829 	__u32 ctsn_ack_point;
1830 
1831 	/* PR-SCTP Advanced.Peer.Ack.Point */
1832 	__u32 adv_peer_ack_point;
1833 
1834 	/* Highest TSN that is acknowledged by incoming SACKs. */
1835 	__u32 highest_sacked;
1836 
1837 	/* TSN marking the fast recovery exit point */
1838 	__u32 fast_recovery_exit;
1839 
1840 	/* Flag to track the current fast recovery state */
1841 	__u8 fast_recovery;
1842 
1843 	/* The number of unacknowledged data chunks.  Reported through
1844 	 * the SCTP_STATUS sockopt.
1845 	 */
1846 	__u16 unack_data;
1847 
1848 	/* The total number of data chunks that we've had to retransmit
1849 	 * as the result of a T3 timer expiration
1850 	 */
1851 	__u32 rtx_data_chunks;
1852 
1853 	/* This is the association's receive buffer space.  This value is used
1854 	 * to set a_rwnd field in an INIT or a SACK chunk.
1855 	 */
1856 	__u32 rwnd;
1857 
1858 	/* This is the last advertised value of rwnd over a SACK chunk. */
1859 	__u32 a_rwnd;
1860 
1861 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1862 	 * to slop over a maximum of the association's frag_point.
1863 	 */
1864 	__u32 rwnd_over;
1865 
1866 	/* Keeps treack of rwnd pressure.  This happens when we have
1867 	 * a window, but not recevie buffer (i.e small packets).  This one
1868 	 * is releases slowly (1 PMTU at a time ).
1869 	 */
1870 	__u32 rwnd_press;
1871 
1872 	/* This is the sndbuf size in use for the association.
1873 	 * This corresponds to the sndbuf size for the association,
1874 	 * as specified in the sk->sndbuf.
1875 	 */
1876 	int sndbuf_used;
1877 
1878 	/* This is the amount of memory that this association has allocated
1879 	 * in the receive path at any given time.
1880 	 */
1881 	atomic_t rmem_alloc;
1882 
1883 	/* This is the wait queue head for send requests waiting on
1884 	 * the association sndbuf space.
1885 	 */
1886 	wait_queue_head_t	wait;
1887 
1888 	/* The message size at which SCTP fragmentation will occur. */
1889 	__u32 frag_point;
1890 	__u32 user_frag;
1891 
1892 	/* Counter used to count INIT errors. */
1893 	int init_err_counter;
1894 
1895 	/* Count the number of INIT cycles (for doubling timeout). */
1896 	int init_cycle;
1897 
1898 	/* Default send parameters. */
1899 	__u16 default_stream;
1900 	__u16 default_flags;
1901 	__u32 default_ppid;
1902 	__u32 default_context;
1903 	__u32 default_timetolive;
1904 
1905 	/* Default receive parameters */
1906 	__u32 default_rcv_context;
1907 
1908 	/* Stream arrays */
1909 	struct sctp_stream stream;
1910 
1911 	/* All outbound chunks go through this structure.  */
1912 	struct sctp_outq outqueue;
1913 
1914 	/* A smart pipe that will handle reordering and fragmentation,
1915 	 * as well as handle passing events up to the ULP.
1916 	 */
1917 	struct sctp_ulpq ulpq;
1918 
1919 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1920 	__u32 last_ecne_tsn;
1921 
1922 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1923 	__u32 last_cwr_tsn;
1924 
1925 	/* How many duplicated TSNs have we seen?  */
1926 	int numduptsns;
1927 
1928 	/* These are to support
1929 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1930 	 *  and Enforcement of Flow and Message Limits"
1931 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1932 	 * or "ADDIP" for short.
1933 	 */
1934 
1935 
1936 
1937 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1938 	 *
1939 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1940 	 * unacknowledged at any one time.  If a sender, after sending
1941 	 * an ASCONF chunk, decides it needs to transfer another
1942 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1943 	 * returns from the previous ASCONF Chunk before sending a
1944 	 * subsequent ASCONF. Note this restriction binds each side,
1945 	 * so at any time two ASCONF may be in-transit on any given
1946 	 * association (one sent from each endpoint).
1947 	 *
1948 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1949 	 * not have an ASCONF in flight, this is NULL.]
1950 	 */
1951 	struct sctp_chunk *addip_last_asconf;
1952 
1953 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1954 	 *
1955 	 * This is needed to implement itmes E1 - E4 of the updated
1956 	 * spec.  Here is the justification:
1957 	 *
1958 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1959 	 * we now need the ability to cache multiple ACKs.  The section
1960 	 * describes in detail how they are cached and cleaned up.
1961 	 */
1962 	struct list_head asconf_ack_list;
1963 
1964 	/* These ASCONF chunks are waiting to be sent.
1965 	 *
1966 	 * These chunaks can't be pushed to outqueue until receiving
1967 	 * ASCONF_ACK for the previous ASCONF indicated by
1968 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1969 	 * is in flight at any time.
1970 	 *
1971 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1972 	 *
1973 	 * In defining the ASCONF Chunk transfer procedures, it is
1974 	 * essential that these transfers MUST NOT cause congestion
1975 	 * within the network.	To achieve this, we place these
1976 	 * restrictions on the transfer of ASCONF Chunks:
1977 	 *
1978 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1979 	 * unacknowledged at any one time.  If a sender, after sending
1980 	 * an ASCONF chunk, decides it needs to transfer another
1981 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1982 	 * returns from the previous ASCONF Chunk before sending a
1983 	 * subsequent ASCONF. Note this restriction binds each side,
1984 	 * so at any time two ASCONF may be in-transit on any given
1985 	 * association (one sent from each endpoint).
1986 	 *
1987 	 *
1988 	 * [I really think this is EXACTLY the sort of intelligence
1989 	 *  which already resides in sctp_outq.	 Please move this
1990 	 *  queue and its supporting logic down there.	--piggy]
1991 	 */
1992 	struct list_head addip_chunk_list;
1993 
1994 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1995 	 *
1996 	 * A2) A serial number should be assigned to the Chunk. The
1997 	 * serial number SHOULD be a monotonically increasing
1998 	 * number. The serial number SHOULD be initialized at
1999 	 * the start of the association to the same value as the
2000 	 * Initial TSN and every time a new ASCONF chunk is created
2001 	 * it is incremented by one after assigning the serial number
2002 	 * to the newly created chunk.
2003 	 *
2004 	 * ADDIP
2005 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
2006 	 *
2007 	 * Serial Number : 32 bits (unsigned integer)
2008 	 *
2009 	 * This value represents a Serial Number for the ASCONF
2010 	 * Chunk. The valid range of Serial Number is from 0 to
2011 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
2012 	 * after reaching 4294967295.
2013 	 */
2014 	__u32 addip_serial;
2015 	int src_out_of_asoc_ok;
2016 	union sctp_addr *asconf_addr_del_pending;
2017 	struct sctp_transport *new_transport;
2018 
2019 	/* SCTP AUTH: list of the endpoint shared keys.  These
2020 	 * keys are provided out of band by the user applicaton
2021 	 * and can't change during the lifetime of the association
2022 	 */
2023 	struct list_head endpoint_shared_keys;
2024 
2025 	/* SCTP AUTH:
2026 	 * The current generated assocaition shared key (secret)
2027 	 */
2028 	struct sctp_auth_bytes *asoc_shared_key;
2029 	struct sctp_shared_key *shkey;
2030 
2031 	/* SCTP AUTH: hmac id of the first peer requested algorithm
2032 	 * that we support.
2033 	 */
2034 	__u16 default_hmac_id;
2035 
2036 	__u16 active_key_id;
2037 
2038 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
2039 	     temp:1,		/* Is it a temporary association? */
2040 	     force_delay:1,
2041 	     intl_enable:1,
2042 	     prsctp_enable:1,
2043 	     reconf_enable:1;
2044 
2045 	__u8 strreset_enable;
2046 	__u8 strreset_outstanding; /* request param count on the fly */
2047 
2048 	__u32 strreset_outseq; /* Update after receiving response */
2049 	__u32 strreset_inseq; /* Update after receiving request */
2050 	__u32 strreset_result[2]; /* save the results of last 2 responses */
2051 
2052 	struct sctp_chunk *strreset_chunk; /* save request chunk */
2053 
2054 	struct sctp_priv_assoc_stats stats;
2055 
2056 	int sent_cnt_removable;
2057 
2058 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2059 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2060 };
2061 
2062 
2063 /* An eyecatcher for determining if we are really looking at an
2064  * association data structure.
2065  */
2066 enum {
2067 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
2068 };
2069 
2070 /* Recover the outter association structure. */
2071 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2072 {
2073 	struct sctp_association *asoc;
2074 
2075 	asoc = container_of(base, struct sctp_association, base);
2076 	return asoc;
2077 }
2078 
2079 /* These are function signatures for manipulating associations.	 */
2080 
2081 
2082 struct sctp_association *
2083 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2084 		     enum sctp_scope scope, gfp_t gfp);
2085 void sctp_association_free(struct sctp_association *);
2086 void sctp_association_put(struct sctp_association *);
2087 void sctp_association_hold(struct sctp_association *);
2088 
2089 struct sctp_transport *sctp_assoc_choose_alter_transport(
2090 	struct sctp_association *, struct sctp_transport *);
2091 void sctp_assoc_update_retran_path(struct sctp_association *);
2092 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2093 					  const union sctp_addr *);
2094 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2095 			    const union sctp_addr *laddr);
2096 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2097 				     const union sctp_addr *address,
2098 				     const gfp_t gfp,
2099 				     const int peer_state);
2100 void sctp_assoc_del_peer(struct sctp_association *asoc,
2101 			 const union sctp_addr *addr);
2102 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2103 			 struct sctp_transport *peer);
2104 void sctp_assoc_control_transport(struct sctp_association *asoc,
2105 				  struct sctp_transport *transport,
2106 				  enum sctp_transport_cmd command,
2107 				  sctp_sn_error_t error);
2108 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2109 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2110 int sctp_assoc_update(struct sctp_association *old,
2111 		      struct sctp_association *new);
2112 
2113 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2114 
2115 void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2116 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2117 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2118 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2119 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2120 void sctp_assoc_set_primary(struct sctp_association *,
2121 			    struct sctp_transport *);
2122 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2123 				    struct sctp_transport *);
2124 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2125 				     enum sctp_scope scope, gfp_t gfp);
2126 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2127 					 struct sctp_cookie*,
2128 					 gfp_t gfp);
2129 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2130 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2131 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2132 					const struct sctp_association *asoc,
2133 					__be32 serial);
2134 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2135 
2136 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2137 			const union sctp_addr *ss2);
2138 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2139 
2140 /* A convenience structure to parse out SCTP specific CMSGs. */
2141 struct sctp_cmsgs {
2142 	struct sctp_initmsg *init;
2143 	struct sctp_sndrcvinfo *srinfo;
2144 	struct sctp_sndinfo *sinfo;
2145 	struct sctp_prinfo *prinfo;
2146 	struct sctp_authinfo *authinfo;
2147 	struct msghdr *addrs_msg;
2148 };
2149 
2150 /* Structure for tracking memory objects */
2151 struct sctp_dbg_objcnt_entry {
2152 	char *label;
2153 	atomic_t *counter;
2154 };
2155 
2156 #endif /* __sctp_structs_h__ */
2157