xref: /openbmc/linux/include/net/sctp/structs.h (revision 62e59c4e)
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/generic-radix-tree.h>
52 #include <linux/rhashtable-types.h>
53 #include <linux/socket.h>	/* linux/in.h needs this!!    */
54 #include <linux/in.h>		/* We get struct sockaddr_in. */
55 #include <linux/in6.h>		/* We get struct in6_addr     */
56 #include <linux/ipv6.h>
57 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
58 #include <linux/atomic.h>		/* This gets us atomic counters.  */
59 #include <linux/skbuff.h>	/* We need sk_buff_head. */
60 #include <linux/workqueue.h>	/* We need tq_struct.	 */
61 #include <linux/sctp.h>		/* We need sctp* header structs.  */
62 #include <net/sctp/auth.h>	/* We need auth specific structs */
63 #include <net/ip.h>		/* For inet_skb_parm */
64 
65 /* A convenience structure for handling sockaddr structures.
66  * We should wean ourselves off this.
67  */
68 union sctp_addr {
69 	struct sockaddr_in v4;
70 	struct sockaddr_in6 v6;
71 	struct sockaddr sa;
72 };
73 
74 /* Forward declarations for data structures. */
75 struct sctp_globals;
76 struct sctp_endpoint;
77 struct sctp_association;
78 struct sctp_transport;
79 struct sctp_packet;
80 struct sctp_chunk;
81 struct sctp_inq;
82 struct sctp_outq;
83 struct sctp_bind_addr;
84 struct sctp_ulpq;
85 struct sctp_ep_common;
86 struct crypto_shash;
87 struct sctp_stream;
88 
89 
90 #include <net/sctp/tsnmap.h>
91 #include <net/sctp/ulpevent.h>
92 #include <net/sctp/ulpqueue.h>
93 #include <net/sctp/stream_interleave.h>
94 
95 /* Structures useful for managing bind/connect. */
96 
97 struct sctp_bind_bucket {
98 	unsigned short	port;
99 	signed char	fastreuse;
100 	signed char	fastreuseport;
101 	kuid_t		fastuid;
102 	struct hlist_node	node;
103 	struct hlist_head	owner;
104 	struct net	*net;
105 };
106 
107 struct sctp_bind_hashbucket {
108 	spinlock_t	lock;
109 	struct hlist_head	chain;
110 };
111 
112 /* Used for hashing all associations.  */
113 struct sctp_hashbucket {
114 	rwlock_t	lock;
115 	struct hlist_head	chain;
116 } __attribute__((__aligned__(8)));
117 
118 
119 /* The SCTP globals structure. */
120 extern struct sctp_globals {
121 	/* This is a list of groups of functions for each address
122 	 * family that we support.
123 	 */
124 	struct list_head address_families;
125 
126 	/* This is the hash of all endpoints. */
127 	struct sctp_hashbucket *ep_hashtable;
128 	/* This is the sctp port control hash.	*/
129 	struct sctp_bind_hashbucket *port_hashtable;
130 	/* This is the hash of all transports. */
131 	struct rhltable transport_hashtable;
132 
133 	/* Sizes of above hashtables. */
134 	int ep_hashsize;
135 	int port_hashsize;
136 
137 	/* Default initialization values to be applied to new associations. */
138 	__u16 max_instreams;
139 	__u16 max_outstreams;
140 
141 	/* Flag to indicate whether computing and verifying checksum
142 	 * is disabled. */
143         bool checksum_disable;
144 } sctp_globals;
145 
146 #define sctp_max_instreams		(sctp_globals.max_instreams)
147 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
148 #define sctp_address_families		(sctp_globals.address_families)
149 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
150 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
151 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
152 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
153 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
154 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
155 
156 /* SCTP Socket type: UDP or TCP style. */
157 enum sctp_socket_type {
158 	SCTP_SOCKET_UDP = 0,
159 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
160 	SCTP_SOCKET_TCP
161 };
162 
163 /* Per socket SCTP information. */
164 struct sctp_sock {
165 	/* inet_sock has to be the first member of sctp_sock */
166 	struct inet_sock inet;
167 	/* What kind of a socket is this? */
168 	enum sctp_socket_type type;
169 
170 	/* PF_ family specific functions.  */
171 	struct sctp_pf *pf;
172 
173 	/* Access to HMAC transform. */
174 	struct crypto_shash *hmac;
175 	char *sctp_hmac_alg;
176 
177 	/* What is our base endpointer? */
178 	struct sctp_endpoint *ep;
179 
180 	struct sctp_bind_bucket *bind_hash;
181 	/* Various Socket Options.  */
182 	__u16 default_stream;
183 	__u32 default_ppid;
184 	__u16 default_flags;
185 	__u32 default_context;
186 	__u32 default_timetolive;
187 	__u32 default_rcv_context;
188 	int max_burst;
189 
190 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
191 	 * the destination address every heartbeat interval. This value
192 	 * will be inherited by all new associations.
193 	 */
194 	__u32 hbinterval;
195 
196 	/* This is the max_retrans value for new associations. */
197 	__u16 pathmaxrxt;
198 
199 	__u32 flowlabel;
200 	__u8  dscp;
201 
202 	int pf_retrans;
203 
204 	/* The initial Path MTU to use for new associations. */
205 	__u32 pathmtu;
206 
207 	/* The default SACK delay timeout for new associations. */
208 	__u32 sackdelay;
209 	__u32 sackfreq;
210 
211 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
212 	__u32 param_flags;
213 
214 	__u32 default_ss;
215 
216 	struct sctp_rtoinfo rtoinfo;
217 	struct sctp_paddrparams paddrparam;
218 	struct sctp_assocparams assocparams;
219 
220 	/*
221 	 * These two structures must be grouped together for the usercopy
222 	 * whitelist region.
223 	 */
224 	__u16 subscribe;
225 	struct sctp_initmsg initmsg;
226 
227 	int user_frag;
228 
229 	__u32 autoclose;
230 	__u32 adaptation_ind;
231 	__u32 pd_point;
232 	__u16	nodelay:1,
233 		reuse:1,
234 		disable_fragments:1,
235 		v4mapped:1,
236 		frag_interleave:1,
237 		strm_interleave:1,
238 		recvrcvinfo:1,
239 		recvnxtinfo:1,
240 		data_ready_signalled:1;
241 
242 	atomic_t pd_mode;
243 	/* Receive to here while partial delivery is in effect. */
244 	struct sk_buff_head pd_lobby;
245 
246 	/* These must be the last fields, as they will skipped on copies,
247 	 * like on accept and peeloff operations
248 	 */
249 	struct list_head auto_asconf_list;
250 	int do_auto_asconf;
251 };
252 
253 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
254 {
255        return (struct sctp_sock *)sk;
256 }
257 
258 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
259 {
260        return (struct sock *)sp;
261 }
262 
263 #if IS_ENABLED(CONFIG_IPV6)
264 struct sctp6_sock {
265        struct sctp_sock  sctp;
266        struct ipv6_pinfo inet6;
267 };
268 #endif /* CONFIG_IPV6 */
269 
270 
271 /* This is our APPLICATION-SPECIFIC state cookie.
272  * THIS IS NOT DICTATED BY THE SPECIFICATION.
273  */
274 /* These are the parts of an association which we send in the cookie.
275  * Most of these are straight out of:
276  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
277  *
278  */
279 
280 struct sctp_cookie {
281 
282 	/* My	       : Tag expected in every inbound packet and sent
283 	 * Verification: in the INIT or INIT ACK chunk.
284 	 * Tag	       :
285 	 */
286 	__u32 my_vtag;
287 
288 	/* Peer's      : Tag expected in every outbound packet except
289 	 * Verification: in the INIT chunk.
290 	 * Tag	       :
291 	 */
292 	__u32 peer_vtag;
293 
294 	/* The rest of these are not from the spec, but really need to
295 	 * be in the cookie.
296 	 */
297 
298 	/* My Tie Tag  : Assist in discovering a restarting association. */
299 	__u32 my_ttag;
300 
301 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
302 	__u32 peer_ttag;
303 
304 	/* When does this cookie expire? */
305 	ktime_t expiration;
306 
307 	/* Number of inbound/outbound streams which are set
308 	 * and negotiated during the INIT process.
309 	 */
310 	__u16 sinit_num_ostreams;
311 	__u16 sinit_max_instreams;
312 
313 	/* This is the first sequence number I used.  */
314 	__u32 initial_tsn;
315 
316 	/* This holds the originating address of the INIT packet.  */
317 	union sctp_addr peer_addr;
318 
319 	/* IG Section 2.35.3
320 	 * Include the source port of the INIT-ACK
321 	 */
322 	__u16		my_port;
323 
324 	__u8 prsctp_capable;
325 
326 	/* Padding for future use */
327 	__u8 padding;
328 
329 	__u32 adaptation_ind;
330 
331 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
332 			 SCTP_AUTH_RANDOM_LENGTH];
333 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
334 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
335 
336 	/* This is a shim for my peer's INIT packet, followed by
337 	 * a copy of the raw address list of the association.
338 	 * The length of the raw address list is saved in the
339 	 * raw_addr_list_len field, which will be used at the time when
340 	 * the association TCB is re-constructed from the cookie.
341 	 */
342 	__u32 raw_addr_list_len;
343 	struct sctp_init_chunk peer_init[0];
344 };
345 
346 
347 /* The format of our cookie that we send to our peer. */
348 struct sctp_signed_cookie {
349 	__u8 signature[SCTP_SECRET_SIZE];
350 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
351 	struct sctp_cookie c;
352 } __packed;
353 
354 /* This is another convenience type to allocate memory for address
355  * params for the maximum size and pass such structures around
356  * internally.
357  */
358 union sctp_addr_param {
359 	struct sctp_paramhdr p;
360 	struct sctp_ipv4addr_param v4;
361 	struct sctp_ipv6addr_param v6;
362 };
363 
364 /* A convenience type to allow walking through the various
365  * parameters and avoid casting all over the place.
366  */
367 union sctp_params {
368 	void *v;
369 	struct sctp_paramhdr *p;
370 	struct sctp_cookie_preserve_param *life;
371 	struct sctp_hostname_param *dns;
372 	struct sctp_cookie_param *cookie;
373 	struct sctp_supported_addrs_param *sat;
374 	struct sctp_ipv4addr_param *v4;
375 	struct sctp_ipv6addr_param *v6;
376 	union sctp_addr_param *addr;
377 	struct sctp_adaptation_ind_param *aind;
378 	struct sctp_supported_ext_param *ext;
379 	struct sctp_random_param *random;
380 	struct sctp_chunks_param *chunks;
381 	struct sctp_hmac_algo_param *hmac_algo;
382 	struct sctp_addip_param *addip;
383 };
384 
385 /* RFC 2960.  Section 3.3.5 Heartbeat.
386  *    Heartbeat Information: variable length
387  *    The Sender-specific Heartbeat Info field should normally include
388  *    information about the sender's current time when this HEARTBEAT
389  *    chunk is sent and the destination transport address to which this
390  *    HEARTBEAT is sent (see Section 8.3).
391  */
392 struct sctp_sender_hb_info {
393 	struct sctp_paramhdr param_hdr;
394 	union sctp_addr daddr;
395 	unsigned long sent_at;
396 	__u64 hb_nonce;
397 };
398 
399 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
400 		     gfp_t gfp);
401 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
402 void sctp_stream_free(struct sctp_stream *stream);
403 void sctp_stream_clear(struct sctp_stream *stream);
404 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
405 
406 /* What is the current SSN number for this stream? */
407 #define sctp_ssn_peek(stream, type, sid) \
408 	(sctp_stream_##type((stream), (sid))->ssn)
409 
410 /* Return the next SSN number for this stream.	*/
411 #define sctp_ssn_next(stream, type, sid) \
412 	(sctp_stream_##type((stream), (sid))->ssn++)
413 
414 /* Skip over this ssn and all below. */
415 #define sctp_ssn_skip(stream, type, sid, ssn) \
416 	(sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
417 
418 /* What is the current MID number for this stream? */
419 #define sctp_mid_peek(stream, type, sid) \
420 	(sctp_stream_##type((stream), (sid))->mid)
421 
422 /* Return the next MID number for this stream.  */
423 #define sctp_mid_next(stream, type, sid) \
424 	(sctp_stream_##type((stream), (sid))->mid++)
425 
426 /* Skip over this mid and all below. */
427 #define sctp_mid_skip(stream, type, sid, mid) \
428 	(sctp_stream_##type((stream), (sid))->mid = mid + 1)
429 
430 /* What is the current MID_uo number for this stream? */
431 #define sctp_mid_uo_peek(stream, type, sid) \
432 	(sctp_stream_##type((stream), (sid))->mid_uo)
433 
434 /* Return the next MID_uo number for this stream.  */
435 #define sctp_mid_uo_next(stream, type, sid) \
436 	(sctp_stream_##type((stream), (sid))->mid_uo++)
437 
438 /*
439  * Pointers to address related SCTP functions.
440  * (i.e. things that depend on the address family.)
441  */
442 struct sctp_af {
443 	int		(*sctp_xmit)	(struct sk_buff *skb,
444 					 struct sctp_transport *);
445 	int		(*setsockopt)	(struct sock *sk,
446 					 int level,
447 					 int optname,
448 					 char __user *optval,
449 					 unsigned int optlen);
450 	int		(*getsockopt)	(struct sock *sk,
451 					 int level,
452 					 int optname,
453 					 char __user *optval,
454 					 int __user *optlen);
455 	int		(*compat_setsockopt)	(struct sock *sk,
456 					 int level,
457 					 int optname,
458 					 char __user *optval,
459 					 unsigned int optlen);
460 	int		(*compat_getsockopt)	(struct sock *sk,
461 					 int level,
462 					 int optname,
463 					 char __user *optval,
464 					 int __user *optlen);
465 	void		(*get_dst)	(struct sctp_transport *t,
466 					 union sctp_addr *saddr,
467 					 struct flowi *fl,
468 					 struct sock *sk);
469 	void		(*get_saddr)	(struct sctp_sock *sk,
470 					 struct sctp_transport *t,
471 					 struct flowi *fl);
472 	void		(*copy_addrlist) (struct list_head *,
473 					  struct net_device *);
474 	int		(*cmp_addr)	(const union sctp_addr *addr1,
475 					 const union sctp_addr *addr2);
476 	void		(*addr_copy)	(union sctp_addr *dst,
477 					 union sctp_addr *src);
478 	void		(*from_skb)	(union sctp_addr *,
479 					 struct sk_buff *skb,
480 					 int saddr);
481 	void		(*from_sk)	(union sctp_addr *,
482 					 struct sock *sk);
483 	void		(*from_addr_param) (union sctp_addr *,
484 					    union sctp_addr_param *,
485 					    __be16 port, int iif);
486 	int		(*to_addr_param) (const union sctp_addr *,
487 					  union sctp_addr_param *);
488 	int		(*addr_valid)	(union sctp_addr *,
489 					 struct sctp_sock *,
490 					 const struct sk_buff *);
491 	enum sctp_scope	(*scope)(union sctp_addr *);
492 	void		(*inaddr_any)	(union sctp_addr *, __be16);
493 	int		(*is_any)	(const union sctp_addr *);
494 	int		(*available)	(union sctp_addr *,
495 					 struct sctp_sock *);
496 	int		(*skb_iif)	(const struct sk_buff *sk);
497 	int		(*is_ce)	(const struct sk_buff *sk);
498 	void		(*seq_dump_addr)(struct seq_file *seq,
499 					 union sctp_addr *addr);
500 	void		(*ecn_capable)(struct sock *sk);
501 	__u16		net_header_len;
502 	int		sockaddr_len;
503 	int		(*ip_options_len)(struct sock *sk);
504 	sa_family_t	sa_family;
505 	struct list_head list;
506 };
507 
508 struct sctp_af *sctp_get_af_specific(sa_family_t);
509 int sctp_register_af(struct sctp_af *);
510 
511 /* Protocol family functions. */
512 struct sctp_pf {
513 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
514 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
515 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
516 	int  (*cmp_addr) (const union sctp_addr *,
517 			  const union sctp_addr *,
518 			  struct sctp_sock *);
519 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
520 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
521 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
522 	struct sock *(*create_accept_sk) (struct sock *sk,
523 					  struct sctp_association *asoc,
524 					  bool kern);
525 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
526 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
527 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
528 	void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
529 	struct sctp_af *af;
530 };
531 
532 
533 /* Structure to track chunk fragments that have been acked, but peer
534  * fragments of the same message have not.
535  */
536 struct sctp_datamsg {
537 	/* Chunks waiting to be submitted to lower layer. */
538 	struct list_head chunks;
539 	/* Reference counting. */
540 	refcount_t refcnt;
541 	/* When is this message no longer interesting to the peer? */
542 	unsigned long expires_at;
543 	/* Did the messenge fail to send? */
544 	int send_error;
545 	u8 send_failed:1,
546 	   can_delay:1,	/* should this message be Nagle delayed */
547 	   abandoned:1;	/* should this message be abandoned */
548 };
549 
550 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
551 					    struct sctp_sndrcvinfo *,
552 					    struct iov_iter *);
553 void sctp_datamsg_free(struct sctp_datamsg *);
554 void sctp_datamsg_put(struct sctp_datamsg *);
555 void sctp_chunk_fail(struct sctp_chunk *, int error);
556 int sctp_chunk_abandoned(struct sctp_chunk *);
557 
558 /* RFC2960 1.4 Key Terms
559  *
560  * o Chunk: A unit of information within an SCTP packet, consisting of
561  * a chunk header and chunk-specific content.
562  *
563  * As a matter of convenience, we remember the SCTP common header for
564  * each chunk as well as a few other header pointers...
565  */
566 struct sctp_chunk {
567 	struct list_head list;
568 
569 	refcount_t refcnt;
570 
571 	/* How many times this chunk have been sent, for prsctp RTX policy */
572 	int sent_count;
573 
574 	union {
575 		/* This is our link to the per-transport transmitted list.  */
576 		struct list_head transmitted_list;
577 		/* List in specific stream outq */
578 		struct list_head stream_list;
579 	};
580 
581 	/* This field is used by chunks that hold fragmented data.
582 	 * For the first fragment this is the list that holds the rest of
583 	 * fragments. For the remaining fragments, this is the link to the
584 	 * frag_list maintained in the first fragment.
585 	 */
586 	struct list_head frag_list;
587 
588 	/* This points to the sk_buff containing the actual data.  */
589 	struct sk_buff *skb;
590 
591 	union {
592 		/* In case of GSO packets, this will store the head one */
593 		struct sk_buff *head_skb;
594 		/* In case of auth enabled, this will point to the shkey */
595 		struct sctp_shared_key *shkey;
596 	};
597 
598 	/* These are the SCTP headers by reverse order in a packet.
599 	 * Note that some of these may happen more than once.  In that
600 	 * case, we point at the "current" one, whatever that means
601 	 * for that level of header.
602 	 */
603 
604 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
605 	union sctp_params param_hdr;
606 	union {
607 		__u8 *v;
608 		struct sctp_datahdr *data_hdr;
609 		struct sctp_inithdr *init_hdr;
610 		struct sctp_sackhdr *sack_hdr;
611 		struct sctp_heartbeathdr *hb_hdr;
612 		struct sctp_sender_hb_info *hbs_hdr;
613 		struct sctp_shutdownhdr *shutdown_hdr;
614 		struct sctp_signed_cookie *cookie_hdr;
615 		struct sctp_ecnehdr *ecne_hdr;
616 		struct sctp_cwrhdr *ecn_cwr_hdr;
617 		struct sctp_errhdr *err_hdr;
618 		struct sctp_addiphdr *addip_hdr;
619 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
620 		struct sctp_authhdr *auth_hdr;
621 		struct sctp_idatahdr *idata_hdr;
622 		struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
623 	} subh;
624 
625 	__u8 *chunk_end;
626 
627 	struct sctp_chunkhdr *chunk_hdr;
628 	struct sctphdr *sctp_hdr;
629 
630 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
631 	struct sctp_sndrcvinfo sinfo;
632 
633 	/* Which association does this belong to?  */
634 	struct sctp_association *asoc;
635 
636 	/* What endpoint received this chunk? */
637 	struct sctp_ep_common *rcvr;
638 
639 	/* We fill this in if we are calculating RTT. */
640 	unsigned long sent_at;
641 
642 	/* What is the origin IP address for this chunk?  */
643 	union sctp_addr source;
644 	/* Destination address for this chunk. */
645 	union sctp_addr dest;
646 
647 	/* For outbound message, track all fragments for SEND_FAILED. */
648 	struct sctp_datamsg *msg;
649 
650 	/* For an inbound chunk, this tells us where it came from.
651 	 * For an outbound chunk, it tells us where we'd like it to
652 	 * go.	It is NULL if we have no preference.
653 	 */
654 	struct sctp_transport *transport;
655 
656 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
657 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
658 	 * spec violates the principle premis that all chunks are processed
659 	 * in order.
660 	 */
661 	struct sk_buff *auth_chunk;
662 
663 #define SCTP_CAN_FRTX 0x0
664 #define SCTP_NEED_FRTX 0x1
665 #define SCTP_DONT_FRTX 0x2
666 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
667 		has_tsn:1,		/* Does this chunk have a TSN yet? */
668 		has_ssn:1,		/* Does this chunk have a SSN yet? */
669 #define has_mid has_ssn
670 		singleton:1,		/* Only chunk in the packet? */
671 		end_of_packet:1,	/* Last chunk in the packet? */
672 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
673 		pdiscard:1,		/* Discard the whole packet now? */
674 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
675 		data_accepted:1,	/* At least 1 chunk accepted */
676 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
677 		has_asconf:1,		/* IN: have seen an asconf before */
678 		tsn_missing_report:2,	/* Data chunk missing counter. */
679 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
680 };
681 
682 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
683 void sctp_chunk_hold(struct sctp_chunk *);
684 void sctp_chunk_put(struct sctp_chunk *);
685 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
686 			  struct iov_iter *from);
687 void sctp_chunk_free(struct sctp_chunk *);
688 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
689 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
690 				 const struct sctp_association *,
691 				 struct sock *, gfp_t gfp);
692 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
693 		     union sctp_addr *);
694 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
695 
696 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
697 {
698 	return ntohs(ch->subh.data_hdr->stream);
699 }
700 
701 enum {
702 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
703 	SCTP_ADDR_SRC,		/* address can be used as source */
704 	SCTP_ADDR_DEL,		/* address about to be deleted */
705 };
706 
707 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
708 struct sctp_sockaddr_entry {
709 	struct list_head list;
710 	struct rcu_head	rcu;
711 	union sctp_addr a;
712 	__u8 state;
713 	__u8 valid;
714 };
715 
716 #define SCTP_ADDRESS_TICK_DELAY	500
717 
718 /* This structure holds lists of chunks as we are assembling for
719  * transmission.
720  */
721 struct sctp_packet {
722 	/* These are the SCTP header values (host order) for the packet. */
723 	__u16 source_port;
724 	__u16 destination_port;
725 	__u32 vtag;
726 
727 	/* This contains the payload chunks.  */
728 	struct list_head chunk_list;
729 
730 	/* This is the overhead of the sctp and ip headers. */
731 	size_t overhead;
732 	/* This is the total size of all chunks INCLUDING padding.  */
733 	size_t size;
734 	/* This is the maximum size this packet may have */
735 	size_t max_size;
736 
737 	/* The packet is destined for this transport address.
738 	 * The function we finally use to pass down to the next lower
739 	 * layer lives in the transport structure.
740 	 */
741 	struct sctp_transport *transport;
742 
743 	/* pointer to the auth chunk for this packet */
744 	struct sctp_chunk *auth;
745 
746 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
747 	    has_sack:1,		/* This packet contains a SACK chunk. */
748 	    has_auth:1,		/* This packet contains an AUTH chunk */
749 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
750 	    ipfragok:1;		/* So let ip fragment this packet */
751 };
752 
753 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
754 		      __u16 sport, __u16 dport);
755 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
756 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
757 					  struct sctp_chunk *chunk,
758 					  int one_packet, gfp_t gfp);
759 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
760 					struct sctp_chunk *chunk);
761 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
762 void sctp_packet_free(struct sctp_packet *);
763 
764 static inline int sctp_packet_empty(struct sctp_packet *packet)
765 {
766 	return packet->size == packet->overhead;
767 }
768 
769 /* This represents a remote transport address.
770  * For local transport addresses, we just use union sctp_addr.
771  *
772  * RFC2960 Section 1.4 Key Terms
773  *
774  *   o	Transport address:  A Transport Address is traditionally defined
775  *	by Network Layer address, Transport Layer protocol and Transport
776  *	Layer port number.  In the case of SCTP running over IP, a
777  *	transport address is defined by the combination of an IP address
778  *	and an SCTP port number (where SCTP is the Transport protocol).
779  *
780  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
781  *
782  *   o	The sender keeps a separate congestion control parameter set for
783  *	each of the destination addresses it can send to (not each
784  *	source-destination pair but for each destination).  The parameters
785  *	should decay if the address is not used for a long enough time
786  *	period.
787  *
788  */
789 struct sctp_transport {
790 	/* A list of transports. */
791 	struct list_head transports;
792 	struct rhlist_head node;
793 
794 	/* Reference counting. */
795 	refcount_t refcnt;
796 		/* RTO-Pending : A flag used to track if one of the DATA
797 		 *		chunks sent to this address is currently being
798 		 *		used to compute a RTT. If this flag is 0,
799 		 *		the next DATA chunk sent to this destination
800 		 *		should be used to compute a RTT and this flag
801 		 *		should be set. Every time the RTT
802 		 *		calculation completes (i.e. the DATA chunk
803 		 *		is SACK'd) clear this flag.
804 		 */
805 	__u32	rto_pending:1,
806 
807 		/*
808 		 * hb_sent : a flag that signals that we have a pending
809 		 * heartbeat.
810 		 */
811 		hb_sent:1,
812 
813 		/* Is the Path MTU update pending on this tranport */
814 		pmtu_pending:1,
815 
816 		dst_pending_confirm:1,	/* need to confirm neighbour */
817 
818 		/* Has this transport moved the ctsn since we last sacked */
819 		sack_generation:1;
820 	u32 dst_cookie;
821 
822 	struct flowi fl;
823 
824 	/* This is the peer's IP address and port. */
825 	union sctp_addr ipaddr;
826 
827 	/* These are the functions we call to handle LLP stuff.	 */
828 	struct sctp_af *af_specific;
829 
830 	/* Which association do we belong to?  */
831 	struct sctp_association *asoc;
832 
833 	/* RFC2960
834 	 *
835 	 * 12.3 Per Transport Address Data
836 	 *
837 	 * For each destination transport address in the peer's
838 	 * address list derived from the INIT or INIT ACK chunk, a
839 	 * number of data elements needs to be maintained including:
840 	 */
841 	/* RTO	       : The current retransmission timeout value.  */
842 	unsigned long rto;
843 
844 	__u32 rtt;		/* This is the most recent RTT.	 */
845 
846 	/* RTTVAR      : The current RTT variation.  */
847 	__u32 rttvar;
848 
849 	/* SRTT	       : The current smoothed round trip time.	*/
850 	__u32 srtt;
851 
852 	/*
853 	 * These are the congestion stats.
854 	 */
855 	/* cwnd	       : The current congestion window.	 */
856 	__u32 cwnd;		  /* This is the actual cwnd.  */
857 
858 	/* ssthresh    : The current slow start threshold value.  */
859 	__u32 ssthresh;
860 
861 	/* partial     : The tracking method for increase of cwnd when in
862 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
863 	 */
864 	__u32 partial_bytes_acked;
865 
866 	/* Data that has been sent, but not acknowledged. */
867 	__u32 flight_size;
868 
869 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
870 
871 	/* Destination */
872 	struct dst_entry *dst;
873 	/* Source address. */
874 	union sctp_addr saddr;
875 
876 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
877 	 * the destination address every heartbeat interval.
878 	 */
879 	unsigned long hbinterval;
880 
881 	/* SACK delay timeout */
882 	unsigned long sackdelay;
883 	__u32 sackfreq;
884 
885 	atomic_t mtu_info;
886 
887 	/* When was the last time that we heard from this transport? We use
888 	 * this to pick new active and retran paths.
889 	 */
890 	ktime_t last_time_heard;
891 
892 	/* When was the last time that we sent a chunk using this
893 	 * transport? We use this to check for idle transports
894 	 */
895 	unsigned long last_time_sent;
896 
897 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
898 	 * indication based on ECNE chunk.
899 	 */
900 	unsigned long last_time_ecne_reduced;
901 
902 	/* This is the max_retrans value for the transport and will
903 	 * be initialized from the assocs value.  This can be changed
904 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
905 	 */
906 	__u16 pathmaxrxt;
907 
908 	__u32 flowlabel;
909 	__u8  dscp;
910 
911 	/* This is the partially failed retrans value for the transport
912 	 * and will be initialized from the assocs value.  This can be changed
913 	 * using the SCTP_PEER_ADDR_THLDS socket option
914 	 */
915 	int pf_retrans;
916 	/* PMTU	      : The current known path MTU.  */
917 	__u32 pathmtu;
918 
919 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
920 	__u32 param_flags;
921 
922 	/* The number of times INIT has been sent on this transport. */
923 	int init_sent_count;
924 
925 	/* state       : The current state of this destination,
926 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
927 	 */
928 	int state;
929 
930 	/* These are the error stats for this destination.  */
931 
932 	/* Error count : The current error count for this destination.	*/
933 	unsigned short error_count;
934 
935 	/* Per	       : A timer used by each destination.
936 	 * Destination :
937 	 * Timer       :
938 	 *
939 	 * [Everywhere else in the text this is called T3-rtx. -ed]
940 	 */
941 	struct timer_list T3_rtx_timer;
942 
943 	/* Heartbeat timer is per destination. */
944 	struct timer_list hb_timer;
945 
946 	/* Timer to handle ICMP proto unreachable envets */
947 	struct timer_list proto_unreach_timer;
948 
949 	/* Timer to handler reconf chunk rtx */
950 	struct timer_list reconf_timer;
951 
952 	/* Since we're using per-destination retransmission timers
953 	 * (see above), we're also using per-destination "transmitted"
954 	 * queues.  This probably ought to be a private struct
955 	 * accessible only within the outqueue, but it's not, yet.
956 	 */
957 	struct list_head transmitted;
958 
959 	/* We build bundle-able packets for this transport here.  */
960 	struct sctp_packet packet;
961 
962 	/* This is the list of transports that have chunks to send.  */
963 	struct list_head send_ready;
964 
965 	/* State information saved for SFR_CACC algorithm. The key
966 	 * idea in SFR_CACC is to maintain state at the sender on a
967 	 * per-destination basis when a changeover happens.
968 	 *	char changeover_active;
969 	 *	char cycling_changeover;
970 	 *	__u32 next_tsn_at_change;
971 	 *	char cacc_saw_newack;
972 	 */
973 	struct {
974 		/* An unsigned integer, which stores the next TSN to be
975 		 * used by the sender, at the moment of changeover.
976 		 */
977 		__u32 next_tsn_at_change;
978 
979 		/* A flag which indicates the occurrence of a changeover */
980 		char changeover_active;
981 
982 		/* A flag which indicates whether the change of primary is
983 		 * the first switch to this destination address during an
984 		 * active switch.
985 		 */
986 		char cycling_changeover;
987 
988 		/* A temporary flag, which is used during the processing of
989 		 * a SACK to estimate the causative TSN(s)'s group.
990 		 */
991 		char cacc_saw_newack;
992 	} cacc;
993 
994 	/* 64-bit random number sent with heartbeat. */
995 	__u64 hb_nonce;
996 
997 	struct rcu_head rcu;
998 };
999 
1000 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
1001 					  gfp_t);
1002 void sctp_transport_set_owner(struct sctp_transport *,
1003 			      struct sctp_association *);
1004 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1005 			  struct sctp_sock *);
1006 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
1007 void sctp_transport_free(struct sctp_transport *);
1008 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
1009 void sctp_transport_reset_hb_timer(struct sctp_transport *);
1010 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
1011 int sctp_transport_hold(struct sctp_transport *);
1012 void sctp_transport_put(struct sctp_transport *);
1013 void sctp_transport_update_rto(struct sctp_transport *, __u32);
1014 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1015 void sctp_transport_lower_cwnd(struct sctp_transport *t,
1016 			       enum sctp_lower_cwnd reason);
1017 void sctp_transport_burst_limited(struct sctp_transport *);
1018 void sctp_transport_burst_reset(struct sctp_transport *);
1019 unsigned long sctp_transport_timeout(struct sctp_transport *);
1020 void sctp_transport_reset(struct sctp_transport *t);
1021 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1022 void sctp_transport_immediate_rtx(struct sctp_transport *);
1023 void sctp_transport_dst_release(struct sctp_transport *t);
1024 void sctp_transport_dst_confirm(struct sctp_transport *t);
1025 
1026 
1027 /* This is the structure we use to queue packets as they come into
1028  * SCTP.  We write packets to it and read chunks from it.
1029  */
1030 struct sctp_inq {
1031 	/* This is actually a queue of sctp_chunk each
1032 	 * containing a partially decoded packet.
1033 	 */
1034 	struct list_head in_chunk_list;
1035 	/* This is the packet which is currently off the in queue and is
1036 	 * being worked on through the inbound chunk processing.
1037 	 */
1038 	struct sctp_chunk *in_progress;
1039 
1040 	/* This is the delayed task to finish delivering inbound
1041 	 * messages.
1042 	 */
1043 	struct work_struct immediate;
1044 };
1045 
1046 void sctp_inq_init(struct sctp_inq *);
1047 void sctp_inq_free(struct sctp_inq *);
1048 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1049 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1050 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1051 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1052 
1053 /* This is the structure we use to hold outbound chunks.  You push
1054  * chunks in and they automatically pop out the other end as bundled
1055  * packets (it calls (*output_handler)()).
1056  *
1057  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1058  * and 8.2 of the v13 draft.
1059  *
1060  * It handles retransmissions.	The connection to the timeout portion
1061  * of the state machine is through sctp_..._timeout() and timeout_handler.
1062  *
1063  * If you feed it SACKs, it will eat them.
1064  *
1065  * If you give it big chunks, it will fragment them.
1066  *
1067  * It assigns TSN's to data chunks.  This happens at the last possible
1068  * instant before transmission.
1069  *
1070  * When free()'d, it empties itself out via output_handler().
1071  */
1072 struct sctp_outq {
1073 	struct sctp_association *asoc;
1074 
1075 	/* Data pending that has never been transmitted.  */
1076 	struct list_head out_chunk_list;
1077 
1078 	/* Stream scheduler being used */
1079 	struct sctp_sched_ops *sched;
1080 
1081 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1082 
1083 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1084 	unsigned int error;
1085 
1086 	/* These are control chunks we want to send.  */
1087 	struct list_head control_chunk_list;
1088 
1089 	/* These are chunks that have been sacked but are above the
1090 	 * CTSN, or cumulative tsn ack point.
1091 	 */
1092 	struct list_head sacked;
1093 
1094 	/* Put chunks on this list to schedule them for
1095 	 * retransmission.
1096 	 */
1097 	struct list_head retransmit;
1098 
1099 	/* Put chunks on this list to save them for FWD TSN processing as
1100 	 * they were abandoned.
1101 	 */
1102 	struct list_head abandoned;
1103 
1104 	/* How many unackd bytes do we have in-flight?	*/
1105 	__u32 outstanding_bytes;
1106 
1107 	/* Are we doing fast-rtx on this queue */
1108 	char fast_rtx;
1109 
1110 	/* Corked? */
1111 	char cork;
1112 };
1113 
1114 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1115 void sctp_outq_teardown(struct sctp_outq *);
1116 void sctp_outq_free(struct sctp_outq*);
1117 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1118 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1119 int sctp_outq_is_empty(const struct sctp_outq *);
1120 void sctp_outq_restart(struct sctp_outq *);
1121 
1122 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1123 		     enum sctp_retransmit_reason reason);
1124 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1125 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1126 void sctp_prsctp_prune(struct sctp_association *asoc,
1127 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1128 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1129 /* Uncork and flush an outqueue.  */
1130 static inline void sctp_outq_cork(struct sctp_outq *q)
1131 {
1132 	q->cork = 1;
1133 }
1134 
1135 /* SCTP skb control block.
1136  * sctp_input_cb is currently used on rx and sock rx queue
1137  */
1138 struct sctp_input_cb {
1139 	union {
1140 		struct inet_skb_parm	h4;
1141 #if IS_ENABLED(CONFIG_IPV6)
1142 		struct inet6_skb_parm	h6;
1143 #endif
1144 	} header;
1145 	struct sctp_chunk *chunk;
1146 	struct sctp_af *af;
1147 };
1148 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1149 
1150 struct sctp_output_cb {
1151 	struct sk_buff *last;
1152 };
1153 #define SCTP_OUTPUT_CB(__skb)	((struct sctp_output_cb *)&((__skb)->cb[0]))
1154 
1155 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1156 {
1157 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1158 
1159 	return chunk->head_skb ? : skb;
1160 }
1161 
1162 /* These bind address data fields common between endpoints and associations */
1163 struct sctp_bind_addr {
1164 
1165 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1166 	 *
1167 	 * SCTP Port:	The local SCTP port number the endpoint is
1168 	 *		bound to.
1169 	 */
1170 	__u16 port;
1171 
1172 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1173 	 *
1174 	 * Address List: The list of IP addresses that this instance
1175 	 *	has bound.  This information is passed to one's
1176 	 *	peer(s) in INIT and INIT ACK chunks.
1177 	 */
1178 	struct list_head address_list;
1179 };
1180 
1181 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1182 void sctp_bind_addr_free(struct sctp_bind_addr *);
1183 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1184 			const struct sctp_bind_addr *src,
1185 			enum sctp_scope scope, gfp_t gfp,
1186 			int flags);
1187 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1188 			const struct sctp_bind_addr *src,
1189 			gfp_t gfp);
1190 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1191 		       int new_size, __u8 addr_state, gfp_t gfp);
1192 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1193 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1194 			 struct sctp_sock *);
1195 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1196 			 struct sctp_sock *, struct sctp_sock *);
1197 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1198 			 const union sctp_addr *addr);
1199 int sctp_bind_addrs_check(struct sctp_sock *sp,
1200 			  struct sctp_sock *sp2, int cnt2);
1201 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1202 					const union sctp_addr	*addrs,
1203 					int			addrcnt,
1204 					struct sctp_sock	*opt);
1205 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1206 					 int *addrs_len,
1207 					 gfp_t gfp);
1208 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1209 			   __u16 port, gfp_t gfp);
1210 
1211 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1212 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1213 		  const enum sctp_scope scope);
1214 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1215 int sctp_is_ep_boundall(struct sock *sk);
1216 
1217 
1218 /* What type of endpoint?  */
1219 enum sctp_endpoint_type {
1220 	SCTP_EP_TYPE_SOCKET,
1221 	SCTP_EP_TYPE_ASSOCIATION,
1222 };
1223 
1224 /*
1225  * A common base class to bridge the implmentation view of a
1226  * socket (usually listening) endpoint versus an association's
1227  * local endpoint.
1228  * This common structure is useful for several purposes:
1229  *   1) Common interface for lookup routines.
1230  *	a) Subfunctions work for either endpoint or association
1231  *	b) Single interface to lookup allows hiding the lookup lock rather
1232  *	   than acquiring it externally.
1233  *   2) Common interface for the inbound chunk handling/state machine.
1234  *   3) Common object handling routines for reference counting, etc.
1235  *   4) Disentangle association lookup from endpoint lookup, where we
1236  *	do not have to find our endpoint to find our association.
1237  *
1238  */
1239 
1240 struct sctp_ep_common {
1241 	/* Fields to help us manage our entries in the hash tables. */
1242 	struct hlist_node node;
1243 	int hashent;
1244 
1245 	/* Runtime type information.  What kind of endpoint is this? */
1246 	enum sctp_endpoint_type type;
1247 
1248 	/* Some fields to help us manage this object.
1249 	 *   refcnt   - Reference count access to this object.
1250 	 *   dead     - Do not attempt to use this object.
1251 	 */
1252 	refcount_t    refcnt;
1253 	bool	    dead;
1254 
1255 	/* What socket does this endpoint belong to?  */
1256 	struct sock *sk;
1257 
1258 	/* This is where we receive inbound chunks.  */
1259 	struct sctp_inq	  inqueue;
1260 
1261 	/* This substructure includes the defining parameters of the
1262 	 * endpoint:
1263 	 * bind_addr.port is our shared port number.
1264 	 * bind_addr.address_list is our set of local IP addresses.
1265 	 */
1266 	struct sctp_bind_addr bind_addr;
1267 };
1268 
1269 
1270 /* RFC Section 1.4 Key Terms
1271  *
1272  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1273  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1274  *   combination of a set of eligible destination transport addresses to
1275  *   which SCTP packets can be sent and a set of eligible source
1276  *   transport addresses from which SCTP packets can be received.
1277  *   All transport addresses used by an SCTP endpoint must use the
1278  *   same port number, but can use multiple IP addresses. A transport
1279  *   address used by an SCTP endpoint must not be used by another
1280  *   SCTP endpoint. In other words, a transport address is unique
1281  *   to an SCTP endpoint.
1282  *
1283  * From an implementation perspective, each socket has one of these.
1284  * A TCP-style socket will have exactly one association on one of
1285  * these.  An UDP-style socket will have multiple associations hanging
1286  * off one of these.
1287  */
1288 
1289 struct sctp_endpoint {
1290 	/* Common substructure for endpoint and association. */
1291 	struct sctp_ep_common base;
1292 
1293 	/* Associations: A list of current associations and mappings
1294 	 *	      to the data consumers for each association. This
1295 	 *	      may be in the form of a hash table or other
1296 	 *	      implementation dependent structure. The data
1297 	 *	      consumers may be process identification
1298 	 *	      information such as file descriptors, named pipe
1299 	 *	      pointer, or table pointers dependent on how SCTP
1300 	 *	      is implemented.
1301 	 */
1302 	/* This is really a list of struct sctp_association entries. */
1303 	struct list_head asocs;
1304 
1305 	/* Secret Key: A secret key used by this endpoint to compute
1306 	 *	      the MAC.	This SHOULD be a cryptographic quality
1307 	 *	      random number with a sufficient length.
1308 	 *	      Discussion in [RFC1750] can be helpful in
1309 	 *	      selection of the key.
1310 	 */
1311 	__u8 secret_key[SCTP_SECRET_SIZE];
1312 
1313  	/* digest:  This is a digest of the sctp cookie.  This field is
1314  	 * 	    only used on the receive path when we try to validate
1315  	 * 	    that the cookie has not been tampered with.  We put
1316  	 * 	    this here so we pre-allocate this once and can re-use
1317  	 * 	    on every receive.
1318  	 */
1319  	__u8 *digest;
1320 
1321 	/* sendbuf acct. policy.	*/
1322 	__u32 sndbuf_policy;
1323 
1324 	/* rcvbuf acct. policy.	*/
1325 	__u32 rcvbuf_policy;
1326 
1327 	/* SCTP AUTH: array of the HMACs that will be allocated
1328 	 * we need this per association so that we don't serialize
1329 	 */
1330 	struct crypto_shash **auth_hmacs;
1331 
1332 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1333 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1334 
1335 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1336 	struct sctp_chunks_param *auth_chunk_list;
1337 
1338 	/* SCTP-AUTH: endpoint shared keys */
1339 	struct list_head endpoint_shared_keys;
1340 	__u16 active_key_id;
1341 	__u8  auth_enable:1,
1342 	      prsctp_enable:1,
1343 	      reconf_enable:1;
1344 
1345 	__u8  strreset_enable;
1346 
1347 	/* Security identifiers from incoming (INIT). These are set by
1348 	 * security_sctp_assoc_request(). These will only be used by
1349 	 * SCTP TCP type sockets and peeled off connections as they
1350 	 * cause a new socket to be generated. security_sctp_sk_clone()
1351 	 * will then plug these into the new socket.
1352 	 */
1353 
1354 	u32 secid;
1355 	u32 peer_secid;
1356 };
1357 
1358 /* Recover the outter endpoint structure. */
1359 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1360 {
1361 	struct sctp_endpoint *ep;
1362 
1363 	ep = container_of(base, struct sctp_endpoint, base);
1364 	return ep;
1365 }
1366 
1367 /* These are function signatures for manipulating endpoints.  */
1368 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1369 void sctp_endpoint_free(struct sctp_endpoint *);
1370 void sctp_endpoint_put(struct sctp_endpoint *);
1371 void sctp_endpoint_hold(struct sctp_endpoint *);
1372 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1373 struct sctp_association *sctp_endpoint_lookup_assoc(
1374 	const struct sctp_endpoint *ep,
1375 	const union sctp_addr *paddr,
1376 	struct sctp_transport **);
1377 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1378 				 const union sctp_addr *paddr);
1379 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1380 					struct net *, const union sctp_addr *);
1381 bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1382 			  const union sctp_addr *paddr);
1383 
1384 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1385 		     const struct sctp_association *asoc,
1386 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1387 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1388 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1389 		      const union sctp_addr *peer,
1390 		      struct sctp_init_chunk *init, gfp_t gfp);
1391 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1392 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1393 
1394 struct sctp_inithdr_host {
1395 	__u32 init_tag;
1396 	__u32 a_rwnd;
1397 	__u16 num_outbound_streams;
1398 	__u16 num_inbound_streams;
1399 	__u32 initial_tsn;
1400 };
1401 
1402 struct sctp_stream_priorities {
1403 	/* List of priorities scheduled */
1404 	struct list_head prio_sched;
1405 	/* List of streams scheduled */
1406 	struct list_head active;
1407 	/* The next stream stream in line */
1408 	struct sctp_stream_out_ext *next;
1409 	__u16 prio;
1410 };
1411 
1412 struct sctp_stream_out_ext {
1413 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1414 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1415 	struct list_head outq; /* chunks enqueued by this stream */
1416 	union {
1417 		struct {
1418 			/* Scheduled streams list */
1419 			struct list_head prio_list;
1420 			struct sctp_stream_priorities *prio_head;
1421 		};
1422 		/* Fields used by RR scheduler */
1423 		struct {
1424 			struct list_head rr_list;
1425 		};
1426 	};
1427 };
1428 
1429 struct sctp_stream_out {
1430 	union {
1431 		__u32 mid;
1432 		__u16 ssn;
1433 	};
1434 	__u32 mid_uo;
1435 	struct sctp_stream_out_ext *ext;
1436 	__u8 state;
1437 };
1438 
1439 struct sctp_stream_in {
1440 	union {
1441 		__u32 mid;
1442 		__u16 ssn;
1443 	};
1444 	__u32 mid_uo;
1445 	__u32 fsn;
1446 	__u32 fsn_uo;
1447 	char pd_mode;
1448 	char pd_mode_uo;
1449 };
1450 
1451 struct sctp_stream {
1452 	GENRADIX(struct sctp_stream_out) out;
1453 	GENRADIX(struct sctp_stream_in)	in;
1454 
1455 	__u16 outcnt;
1456 	__u16 incnt;
1457 	/* Current stream being sent, if any */
1458 	struct sctp_stream_out *out_curr;
1459 	union {
1460 		/* Fields used by priority scheduler */
1461 		struct {
1462 			/* List of priorities scheduled */
1463 			struct list_head prio_list;
1464 		};
1465 		/* Fields used by RR scheduler */
1466 		struct {
1467 			/* List of streams scheduled */
1468 			struct list_head rr_list;
1469 			/* The next stream stream in line */
1470 			struct sctp_stream_out_ext *rr_next;
1471 		};
1472 	};
1473 	struct sctp_stream_interleave *si;
1474 };
1475 
1476 static inline struct sctp_stream_out *sctp_stream_out(
1477 	struct sctp_stream *stream,
1478 	__u16 sid)
1479 {
1480 	return genradix_ptr(&stream->out, sid);
1481 }
1482 
1483 static inline struct sctp_stream_in *sctp_stream_in(
1484 	struct sctp_stream *stream,
1485 	__u16 sid)
1486 {
1487 	return genradix_ptr(&stream->in, sid);
1488 }
1489 
1490 #define SCTP_SO(s, i) sctp_stream_out((s), (i))
1491 #define SCTP_SI(s, i) sctp_stream_in((s), (i))
1492 
1493 #define SCTP_STREAM_CLOSED		0x00
1494 #define SCTP_STREAM_OPEN		0x01
1495 
1496 static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1497 {
1498 	return stream->si->data_chunk_len;
1499 }
1500 
1501 static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1502 {
1503 	return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1504 }
1505 
1506 static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1507 {
1508 	return stream->si->ftsn_chunk_len;
1509 }
1510 
1511 static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1512 {
1513 	return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1514 }
1515 
1516 /* SCTP_GET_ASSOC_STATS counters */
1517 struct sctp_priv_assoc_stats {
1518 	/* Maximum observed rto in the association during subsequent
1519 	 * observations. Value is set to 0 if no RTO measurement took place
1520 	 * The transport where the max_rto was observed is returned in
1521 	 * obs_rto_ipaddr
1522 	 */
1523 	struct sockaddr_storage obs_rto_ipaddr;
1524 	__u64 max_obs_rto;
1525 	/* Total In and Out SACKs received and sent */
1526 	__u64 isacks;
1527 	__u64 osacks;
1528 	/* Total In and Out packets received and sent */
1529 	__u64 opackets;
1530 	__u64 ipackets;
1531 	/* Total retransmitted chunks */
1532 	__u64 rtxchunks;
1533 	/* TSN received > next expected */
1534 	__u64 outofseqtsns;
1535 	/* Duplicate Chunks received */
1536 	__u64 idupchunks;
1537 	/* Gap Ack Blocks received */
1538 	__u64 gapcnt;
1539 	/* Unordered data chunks sent and received */
1540 	__u64 ouodchunks;
1541 	__u64 iuodchunks;
1542 	/* Ordered data chunks sent and received */
1543 	__u64 oodchunks;
1544 	__u64 iodchunks;
1545 	/* Control chunks sent and received */
1546 	__u64 octrlchunks;
1547 	__u64 ictrlchunks;
1548 };
1549 
1550 /* RFC2960
1551  *
1552  * 12. Recommended Transmission Control Block (TCB) Parameters
1553  *
1554  * This section details a recommended set of parameters that should
1555  * be contained within the TCB for an implementation. This section is
1556  * for illustrative purposes and should not be deemed as requirements
1557  * on an implementation or as an exhaustive list of all parameters
1558  * inside an SCTP TCB. Each implementation may need its own additional
1559  * parameters for optimization.
1560  */
1561 
1562 
1563 /* Here we have information about each individual association. */
1564 struct sctp_association {
1565 
1566 	/* A base structure common to endpoint and association.
1567 	 * In this context, it represents the associations's view
1568 	 * of the local endpoint of the association.
1569 	 */
1570 	struct sctp_ep_common base;
1571 
1572 	/* Associations on the same socket. */
1573 	struct list_head asocs;
1574 
1575 	/* association id. */
1576 	sctp_assoc_t assoc_id;
1577 
1578 	/* This is our parent endpoint.	 */
1579 	struct sctp_endpoint *ep;
1580 
1581 	/* These are those association elements needed in the cookie.  */
1582 	struct sctp_cookie c;
1583 
1584 	/* This is all information about our peer.  */
1585 	struct {
1586 		/* transport_addr_list
1587 		 *
1588 		 * Peer	       : A list of SCTP transport addresses that the
1589 		 * Transport   : peer is bound to. This information is derived
1590 		 * Address     : from the INIT or INIT ACK and is used to
1591 		 * List	       : associate an inbound packet with a given
1592 		 *	       : association. Normally this information is
1593 		 *	       : hashed or keyed for quick lookup and access
1594 		 *	       : of the TCB.
1595 		 *	       : The list is also initialized with the list
1596 		 *	       : of addresses passed with the sctp_connectx()
1597 		 *	       : call.
1598 		 *
1599 		 * It is a list of SCTP_transport's.
1600 		 */
1601 		struct list_head transport_addr_list;
1602 
1603 		/* rwnd
1604 		 *
1605 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1606 		 */
1607 		__u32 rwnd;
1608 
1609 		/* transport_count
1610 		 *
1611 		 * Peer        : A count of the number of peer addresses
1612 		 * Transport   : in the Peer Transport Address List.
1613 		 * Address     :
1614 		 * Count       :
1615 		 */
1616 		__u16 transport_count;
1617 
1618 		/* port
1619 		 *   The transport layer port number.
1620 		 */
1621 		__u16 port;
1622 
1623 		/* primary_path
1624 		 *
1625 		 * Primary     : This is the current primary destination
1626 		 * Path	       : transport address of the peer endpoint.  It
1627 		 *	       : may also specify a source transport address
1628 		 *	       : on this endpoint.
1629 		 *
1630 		 * All of these paths live on transport_addr_list.
1631 		 *
1632 		 * At the bakeoffs, we discovered that the intent of
1633 		 * primaryPath is that it only changes when the ULP
1634 		 * asks to have it changed.  We add the activePath to
1635 		 * designate the connection we are currently using to
1636 		 * transmit new data and most control chunks.
1637 		 */
1638 		struct sctp_transport *primary_path;
1639 
1640 		/* Cache the primary path address here, when we
1641 		 * need a an address for msg_name.
1642 		 */
1643 		union sctp_addr primary_addr;
1644 
1645 		/* active_path
1646 		 *   The path that we are currently using to
1647 		 *   transmit new data and most control chunks.
1648 		 */
1649 		struct sctp_transport *active_path;
1650 
1651 		/* retran_path
1652 		 *
1653 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1654 		 * ...
1655 		 * Furthermore, when its peer is multi-homed, an
1656 		 * endpoint SHOULD try to retransmit a chunk to an
1657 		 * active destination transport address that is
1658 		 * different from the last destination address to
1659 		 * which the DATA chunk was sent.
1660 		 */
1661 		struct sctp_transport *retran_path;
1662 
1663 		/* Pointer to last transport I have sent on.  */
1664 		struct sctp_transport *last_sent_to;
1665 
1666 		/* This is the last transport I have received DATA on.	*/
1667 		struct sctp_transport *last_data_from;
1668 
1669 		/*
1670 		 * Mapping  An array of bits or bytes indicating which out of
1671 		 * Array    order TSN's have been received (relative to the
1672 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1673 		 *	    order packets have been received, this array
1674 		 *	    will be set to all zero. This structure may be
1675 		 *	    in the form of a circular buffer or bit array.
1676 		 *
1677 		 * Last Rcvd   : This is the last TSN received in
1678 		 * TSN	       : sequence. This value is set initially by
1679 		 *	       : taking the peer's Initial TSN, received in
1680 		 *	       : the INIT or INIT ACK chunk, and subtracting
1681 		 *	       : one from it.
1682 		 *
1683 		 * Throughout most of the specification this is called the
1684 		 * "Cumulative TSN ACK Point".	In this case, we
1685 		 * ignore the advice in 12.2 in favour of the term
1686 		 * used in the bulk of the text.  This value is hidden
1687 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1688 		 */
1689 		struct sctp_tsnmap tsn_map;
1690 
1691 		/* This mask is used to disable sending the ASCONF chunk
1692 		 * with specified parameter to peer.
1693 		 */
1694 		__be16 addip_disabled_mask;
1695 
1696 		/* These are capabilities which our peer advertised.  */
1697 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1698 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1699 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1700 			hostname_address:1, /* Peer understands DNS addresses? */
1701 			asconf_capable:1,   /* Does peer support ADDIP? */
1702 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1703 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1704 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1705 
1706 		/* sack_needed : This flag indicates if the next received
1707 		 *             : packet is to be responded to with a
1708 		 *             : SACK. This is initialized to 0.  When a packet
1709 		 *             : is received sack_cnt is incremented. If this value
1710 		 *             : reaches 2 or more, a SACK is sent and the
1711 		 *             : value is reset to 0. Note: This is used only
1712 		 *             : when no DATA chunks are received out of
1713 		 *             : order.  When DATA chunks are out of order,
1714 		 *             : SACK's are not delayed (see Section 6).
1715 		 */
1716 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1717 			sack_generation:1,
1718 			zero_window_announced:1;
1719 		__u32	sack_cnt;
1720 
1721 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1722 
1723 		struct sctp_inithdr_host i;
1724 		void *cookie;
1725 		int cookie_len;
1726 
1727 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1728 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1729 		 * Initial TSN Value minus 1
1730 		 */
1731 		__u32 addip_serial;
1732 
1733 		/* SCTP-AUTH: We need to know pears random number, hmac list
1734 		 * and authenticated chunk list.  All that is part of the
1735 		 * cookie and these are just pointers to those locations
1736 		 */
1737 		struct sctp_random_param *peer_random;
1738 		struct sctp_chunks_param *peer_chunks;
1739 		struct sctp_hmac_algo_param *peer_hmacs;
1740 	} peer;
1741 
1742 	/* State       : A state variable indicating what state the
1743 	 *	       : association is in, i.e. COOKIE-WAIT,
1744 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1745 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1746 	 *
1747 	 *		Note: No "CLOSED" state is illustrated since if a
1748 	 *		association is "CLOSED" its TCB SHOULD be removed.
1749 	 *
1750 	 *		In this implementation we DO have a CLOSED
1751 	 *		state which is used during initiation and shutdown.
1752 	 *
1753 	 *		State takes values from SCTP_STATE_*.
1754 	 */
1755 	enum sctp_state state;
1756 
1757 	/* Overall     : The overall association error count.
1758 	 * Error Count : [Clear this any time I get something.]
1759 	 */
1760 	int overall_error_count;
1761 
1762 	/* The cookie life I award for any cookie.  */
1763 	ktime_t cookie_life;
1764 
1765 	/* These are the association's initial, max, and min RTO values.
1766 	 * These values will be initialized by system defaults, but can
1767 	 * be modified via the SCTP_RTOINFO socket option.
1768 	 */
1769 	unsigned long rto_initial;
1770 	unsigned long rto_max;
1771 	unsigned long rto_min;
1772 
1773 	/* Maximum number of new data packets that can be sent in a burst.  */
1774 	int max_burst;
1775 
1776 	/* This is the max_retrans value for the association.  This value will
1777 	 * be initialized initialized from system defaults, but can be
1778 	 * modified by the SCTP_ASSOCINFO socket option.
1779 	 */
1780 	int max_retrans;
1781 
1782 	/* This is the partially failed retrans value for the transport
1783 	 * and will be initialized from the assocs value.  This can be
1784 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1785 	 */
1786 	int pf_retrans;
1787 
1788 	/* Maximum number of times the endpoint will retransmit INIT  */
1789 	__u16 max_init_attempts;
1790 
1791 	/* How many times have we resent an INIT? */
1792 	__u16 init_retries;
1793 
1794 	/* The largest timeout or RTO value to use in attempting an INIT */
1795 	unsigned long max_init_timeo;
1796 
1797 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1798 	 * the destination address every heartbeat interval. This value
1799 	 * will be inherited by all new transports.
1800 	 */
1801 	unsigned long hbinterval;
1802 
1803 	/* This is the max_retrans value for new transports in the
1804 	 * association.
1805 	 */
1806 	__u16 pathmaxrxt;
1807 
1808 	__u32 flowlabel;
1809 	__u8  dscp;
1810 
1811 	/* Flag that path mtu update is pending */
1812 	__u8   pmtu_pending;
1813 
1814 	/* Association : The smallest PMTU discovered for all of the
1815 	 * PMTU	       : peer's transport addresses.
1816 	 */
1817 	__u32 pathmtu;
1818 
1819 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1820 	__u32 param_flags;
1821 
1822 	__u32 sackfreq;
1823 	/* SACK delay timeout */
1824 	unsigned long sackdelay;
1825 
1826 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1827 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1828 
1829 	/* Transport to which SHUTDOWN chunk was last sent.  */
1830 	struct sctp_transport *shutdown_last_sent_to;
1831 
1832 	/* Transport to which INIT chunk was last sent.  */
1833 	struct sctp_transport *init_last_sent_to;
1834 
1835 	/* How many times have we resent a SHUTDOWN */
1836 	int shutdown_retries;
1837 
1838 	/* Next TSN    : The next TSN number to be assigned to a new
1839 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1840 	 *	       : ACK chunk to the peer and incremented each
1841 	 *	       : time a DATA chunk is assigned a TSN
1842 	 *	       : (normally just prior to transmit or during
1843 	 *	       : fragmentation).
1844 	 */
1845 	__u32 next_tsn;
1846 
1847 	/*
1848 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1849 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1850 	 *	       : received in the INIT or INIT ACK chunk, and
1851 	 *	       : subtracting one from it.
1852 	 *
1853 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1854 	 */
1855 
1856 	__u32 ctsn_ack_point;
1857 
1858 	/* PR-SCTP Advanced.Peer.Ack.Point */
1859 	__u32 adv_peer_ack_point;
1860 
1861 	/* Highest TSN that is acknowledged by incoming SACKs. */
1862 	__u32 highest_sacked;
1863 
1864 	/* TSN marking the fast recovery exit point */
1865 	__u32 fast_recovery_exit;
1866 
1867 	/* Flag to track the current fast recovery state */
1868 	__u8 fast_recovery;
1869 
1870 	/* The number of unacknowledged data chunks.  Reported through
1871 	 * the SCTP_STATUS sockopt.
1872 	 */
1873 	__u16 unack_data;
1874 
1875 	/* The total number of data chunks that we've had to retransmit
1876 	 * as the result of a T3 timer expiration
1877 	 */
1878 	__u32 rtx_data_chunks;
1879 
1880 	/* This is the association's receive buffer space.  This value is used
1881 	 * to set a_rwnd field in an INIT or a SACK chunk.
1882 	 */
1883 	__u32 rwnd;
1884 
1885 	/* This is the last advertised value of rwnd over a SACK chunk. */
1886 	__u32 a_rwnd;
1887 
1888 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1889 	 * to slop over a maximum of the association's frag_point.
1890 	 */
1891 	__u32 rwnd_over;
1892 
1893 	/* Keeps treack of rwnd pressure.  This happens when we have
1894 	 * a window, but not recevie buffer (i.e small packets).  This one
1895 	 * is releases slowly (1 PMTU at a time ).
1896 	 */
1897 	__u32 rwnd_press;
1898 
1899 	/* This is the sndbuf size in use for the association.
1900 	 * This corresponds to the sndbuf size for the association,
1901 	 * as specified in the sk->sndbuf.
1902 	 */
1903 	int sndbuf_used;
1904 
1905 	/* This is the amount of memory that this association has allocated
1906 	 * in the receive path at any given time.
1907 	 */
1908 	atomic_t rmem_alloc;
1909 
1910 	/* This is the wait queue head for send requests waiting on
1911 	 * the association sndbuf space.
1912 	 */
1913 	wait_queue_head_t	wait;
1914 
1915 	/* The message size at which SCTP fragmentation will occur. */
1916 	__u32 frag_point;
1917 	__u32 user_frag;
1918 
1919 	/* Counter used to count INIT errors. */
1920 	int init_err_counter;
1921 
1922 	/* Count the number of INIT cycles (for doubling timeout). */
1923 	int init_cycle;
1924 
1925 	/* Default send parameters. */
1926 	__u16 default_stream;
1927 	__u16 default_flags;
1928 	__u32 default_ppid;
1929 	__u32 default_context;
1930 	__u32 default_timetolive;
1931 
1932 	/* Default receive parameters */
1933 	__u32 default_rcv_context;
1934 
1935 	/* Stream arrays */
1936 	struct sctp_stream stream;
1937 
1938 	/* All outbound chunks go through this structure.  */
1939 	struct sctp_outq outqueue;
1940 
1941 	/* A smart pipe that will handle reordering and fragmentation,
1942 	 * as well as handle passing events up to the ULP.
1943 	 */
1944 	struct sctp_ulpq ulpq;
1945 
1946 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1947 	__u32 last_ecne_tsn;
1948 
1949 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1950 	__u32 last_cwr_tsn;
1951 
1952 	/* How many duplicated TSNs have we seen?  */
1953 	int numduptsns;
1954 
1955 	/* These are to support
1956 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1957 	 *  and Enforcement of Flow and Message Limits"
1958 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1959 	 * or "ADDIP" for short.
1960 	 */
1961 
1962 
1963 
1964 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1965 	 *
1966 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1967 	 * unacknowledged at any one time.  If a sender, after sending
1968 	 * an ASCONF chunk, decides it needs to transfer another
1969 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1970 	 * returns from the previous ASCONF Chunk before sending a
1971 	 * subsequent ASCONF. Note this restriction binds each side,
1972 	 * so at any time two ASCONF may be in-transit on any given
1973 	 * association (one sent from each endpoint).
1974 	 *
1975 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1976 	 * not have an ASCONF in flight, this is NULL.]
1977 	 */
1978 	struct sctp_chunk *addip_last_asconf;
1979 
1980 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1981 	 *
1982 	 * This is needed to implement itmes E1 - E4 of the updated
1983 	 * spec.  Here is the justification:
1984 	 *
1985 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1986 	 * we now need the ability to cache multiple ACKs.  The section
1987 	 * describes in detail how they are cached and cleaned up.
1988 	 */
1989 	struct list_head asconf_ack_list;
1990 
1991 	/* These ASCONF chunks are waiting to be sent.
1992 	 *
1993 	 * These chunaks can't be pushed to outqueue until receiving
1994 	 * ASCONF_ACK for the previous ASCONF indicated by
1995 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1996 	 * is in flight at any time.
1997 	 *
1998 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1999 	 *
2000 	 * In defining the ASCONF Chunk transfer procedures, it is
2001 	 * essential that these transfers MUST NOT cause congestion
2002 	 * within the network.	To achieve this, we place these
2003 	 * restrictions on the transfer of ASCONF Chunks:
2004 	 *
2005 	 * R1) One and only one ASCONF Chunk MAY be in transit and
2006 	 * unacknowledged at any one time.  If a sender, after sending
2007 	 * an ASCONF chunk, decides it needs to transfer another
2008 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
2009 	 * returns from the previous ASCONF Chunk before sending a
2010 	 * subsequent ASCONF. Note this restriction binds each side,
2011 	 * so at any time two ASCONF may be in-transit on any given
2012 	 * association (one sent from each endpoint).
2013 	 *
2014 	 *
2015 	 * [I really think this is EXACTLY the sort of intelligence
2016 	 *  which already resides in sctp_outq.	 Please move this
2017 	 *  queue and its supporting logic down there.	--piggy]
2018 	 */
2019 	struct list_head addip_chunk_list;
2020 
2021 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2022 	 *
2023 	 * A2) A serial number should be assigned to the Chunk. The
2024 	 * serial number SHOULD be a monotonically increasing
2025 	 * number. The serial number SHOULD be initialized at
2026 	 * the start of the association to the same value as the
2027 	 * Initial TSN and every time a new ASCONF chunk is created
2028 	 * it is incremented by one after assigning the serial number
2029 	 * to the newly created chunk.
2030 	 *
2031 	 * ADDIP
2032 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
2033 	 *
2034 	 * Serial Number : 32 bits (unsigned integer)
2035 	 *
2036 	 * This value represents a Serial Number for the ASCONF
2037 	 * Chunk. The valid range of Serial Number is from 0 to
2038 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
2039 	 * after reaching 4294967295.
2040 	 */
2041 	__u32 addip_serial;
2042 	int src_out_of_asoc_ok;
2043 	union sctp_addr *asconf_addr_del_pending;
2044 	struct sctp_transport *new_transport;
2045 
2046 	/* SCTP AUTH: list of the endpoint shared keys.  These
2047 	 * keys are provided out of band by the user applicaton
2048 	 * and can't change during the lifetime of the association
2049 	 */
2050 	struct list_head endpoint_shared_keys;
2051 
2052 	/* SCTP AUTH:
2053 	 * The current generated assocaition shared key (secret)
2054 	 */
2055 	struct sctp_auth_bytes *asoc_shared_key;
2056 	struct sctp_shared_key *shkey;
2057 
2058 	/* SCTP AUTH: hmac id of the first peer requested algorithm
2059 	 * that we support.
2060 	 */
2061 	__u16 default_hmac_id;
2062 
2063 	__u16 active_key_id;
2064 
2065 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
2066 	     temp:1,		/* Is it a temporary association? */
2067 	     force_delay:1,
2068 	     intl_enable:1,
2069 	     prsctp_enable:1,
2070 	     reconf_enable:1;
2071 
2072 	__u8 strreset_enable;
2073 	__u8 strreset_outstanding; /* request param count on the fly */
2074 
2075 	__u32 strreset_outseq; /* Update after receiving response */
2076 	__u32 strreset_inseq; /* Update after receiving request */
2077 	__u32 strreset_result[2]; /* save the results of last 2 responses */
2078 
2079 	struct sctp_chunk *strreset_chunk; /* save request chunk */
2080 
2081 	struct sctp_priv_assoc_stats stats;
2082 
2083 	int sent_cnt_removable;
2084 
2085 	__u16 subscribe;
2086 
2087 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2088 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2089 
2090 	struct rcu_head rcu;
2091 };
2092 
2093 
2094 /* An eyecatcher for determining if we are really looking at an
2095  * association data structure.
2096  */
2097 enum {
2098 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
2099 };
2100 
2101 /* Recover the outter association structure. */
2102 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2103 {
2104 	struct sctp_association *asoc;
2105 
2106 	asoc = container_of(base, struct sctp_association, base);
2107 	return asoc;
2108 }
2109 
2110 /* These are function signatures for manipulating associations.	 */
2111 
2112 
2113 struct sctp_association *
2114 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2115 		     enum sctp_scope scope, gfp_t gfp);
2116 void sctp_association_free(struct sctp_association *);
2117 void sctp_association_put(struct sctp_association *);
2118 void sctp_association_hold(struct sctp_association *);
2119 
2120 struct sctp_transport *sctp_assoc_choose_alter_transport(
2121 	struct sctp_association *, struct sctp_transport *);
2122 void sctp_assoc_update_retran_path(struct sctp_association *);
2123 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2124 					  const union sctp_addr *);
2125 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2126 			    const union sctp_addr *laddr);
2127 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2128 				     const union sctp_addr *address,
2129 				     const gfp_t gfp,
2130 				     const int peer_state);
2131 void sctp_assoc_del_peer(struct sctp_association *asoc,
2132 			 const union sctp_addr *addr);
2133 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2134 			 struct sctp_transport *peer);
2135 void sctp_assoc_control_transport(struct sctp_association *asoc,
2136 				  struct sctp_transport *transport,
2137 				  enum sctp_transport_cmd command,
2138 				  sctp_sn_error_t error);
2139 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2140 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2141 int sctp_assoc_update(struct sctp_association *old,
2142 		      struct sctp_association *new);
2143 
2144 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2145 
2146 void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2147 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2148 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2149 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2150 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2151 void sctp_assoc_set_primary(struct sctp_association *,
2152 			    struct sctp_transport *);
2153 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2154 				    struct sctp_transport *);
2155 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2156 				     enum sctp_scope scope, gfp_t gfp);
2157 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2158 					 struct sctp_cookie*,
2159 					 gfp_t gfp);
2160 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2161 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2162 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2163 					const struct sctp_association *asoc,
2164 					__be32 serial);
2165 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2166 
2167 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2168 			const union sctp_addr *ss2);
2169 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2170 
2171 /* A convenience structure to parse out SCTP specific CMSGs. */
2172 struct sctp_cmsgs {
2173 	struct sctp_initmsg *init;
2174 	struct sctp_sndrcvinfo *srinfo;
2175 	struct sctp_sndinfo *sinfo;
2176 	struct sctp_prinfo *prinfo;
2177 	struct sctp_authinfo *authinfo;
2178 	struct msghdr *addrs_msg;
2179 };
2180 
2181 /* Structure for tracking memory objects */
2182 struct sctp_dbg_objcnt_entry {
2183 	char *label;
2184 	atomic_t *counter;
2185 };
2186 
2187 #endif /* __sctp_structs_h__ */
2188