xref: /openbmc/linux/include/net/sctp/structs.h (revision ad05a7a05ede28ba6dd935d9e932264a22518b1f)
1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * This SCTP implementation is free software;
10  * you can redistribute it and/or modify it under the terms of
11  * the GNU General Public License as published by
12  * the Free Software Foundation; either version 2, or (at your option)
13  * any later version.
14  *
15  * This SCTP implementation is distributed in the hope that it
16  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17  *		   ************************
18  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19  * See the GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with GNU CC; see the file COPYING.  If not, see
23  * <http://www.gnu.org/licenses/>.
24  *
25  * Please send any bug reports or fixes you make to the
26  * email addresses:
27  *    lksctp developers <linux-sctp@vger.kernel.org>
28  *
29  * Written or modified by:
30  *    Randall Stewart	    <randall@sctp.chicago.il.us>
31  *    Ken Morneau	    <kmorneau@cisco.com>
32  *    Qiaobing Xie	    <qxie1@email.mot.com>
33  *    La Monte H.P. Yarroll <piggy@acm.org>
34  *    Karl Knutson	    <karl@athena.chicago.il.us>
35  *    Jon Grimm		    <jgrimm@us.ibm.com>
36  *    Xingang Guo	    <xingang.guo@intel.com>
37  *    Hui Huang		    <hui.huang@nokia.com>
38  *    Sridhar Samudrala	    <sri@us.ibm.com>
39  *    Daisy Chang	    <daisyc@us.ibm.com>
40  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
41  *    Ardelle Fan	    <ardelle.fan@intel.com>
42  *    Ryan Layer	    <rmlayer@us.ibm.com>
43  *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
44  *    Kevin Gao             <kevin.gao@intel.com>
45  */
46 
47 #ifndef __sctp_structs_h__
48 #define __sctp_structs_h__
49 
50 #include <linux/ktime.h>
51 #include <linux/rhashtable.h>
52 #include <linux/socket.h>	/* linux/in.h needs this!!    */
53 #include <linux/in.h>		/* We get struct sockaddr_in. */
54 #include <linux/in6.h>		/* We get struct in6_addr     */
55 #include <linux/ipv6.h>
56 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
57 #include <linux/atomic.h>		/* This gets us atomic counters.  */
58 #include <linux/skbuff.h>	/* We need sk_buff_head. */
59 #include <linux/workqueue.h>	/* We need tq_struct.	 */
60 #include <linux/sctp.h>		/* We need sctp* header structs.  */
61 #include <net/sctp/auth.h>	/* We need auth specific structs */
62 #include <net/ip.h>		/* For inet_skb_parm */
63 
64 /* A convenience structure for handling sockaddr structures.
65  * We should wean ourselves off this.
66  */
67 union sctp_addr {
68 	struct sockaddr_in v4;
69 	struct sockaddr_in6 v6;
70 	struct sockaddr sa;
71 };
72 
73 /* Forward declarations for data structures. */
74 struct sctp_globals;
75 struct sctp_endpoint;
76 struct sctp_association;
77 struct sctp_transport;
78 struct sctp_packet;
79 struct sctp_chunk;
80 struct sctp_inq;
81 struct sctp_outq;
82 struct sctp_bind_addr;
83 struct sctp_ulpq;
84 struct sctp_ep_common;
85 struct crypto_shash;
86 struct sctp_stream;
87 
88 
89 #include <net/sctp/tsnmap.h>
90 #include <net/sctp/ulpevent.h>
91 #include <net/sctp/ulpqueue.h>
92 
93 /* Structures useful for managing bind/connect. */
94 
95 struct sctp_bind_bucket {
96 	unsigned short	port;
97 	unsigned short	fastreuse;
98 	struct hlist_node	node;
99 	struct hlist_head	owner;
100 	struct net	*net;
101 };
102 
103 struct sctp_bind_hashbucket {
104 	spinlock_t	lock;
105 	struct hlist_head	chain;
106 };
107 
108 /* Used for hashing all associations.  */
109 struct sctp_hashbucket {
110 	rwlock_t	lock;
111 	struct hlist_head	chain;
112 } __attribute__((__aligned__(8)));
113 
114 
115 /* The SCTP globals structure. */
116 extern struct sctp_globals {
117 	/* This is a list of groups of functions for each address
118 	 * family that we support.
119 	 */
120 	struct list_head address_families;
121 
122 	/* This is the hash of all endpoints. */
123 	struct sctp_hashbucket *ep_hashtable;
124 	/* This is the sctp port control hash.	*/
125 	struct sctp_bind_hashbucket *port_hashtable;
126 	/* This is the hash of all transports. */
127 	struct rhltable transport_hashtable;
128 
129 	/* Sizes of above hashtables. */
130 	int ep_hashsize;
131 	int port_hashsize;
132 
133 	/* Default initialization values to be applied to new associations. */
134 	__u16 max_instreams;
135 	__u16 max_outstreams;
136 
137 	/* Flag to indicate whether computing and verifying checksum
138 	 * is disabled. */
139         bool checksum_disable;
140 } sctp_globals;
141 
142 #define sctp_max_instreams		(sctp_globals.max_instreams)
143 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
144 #define sctp_address_families		(sctp_globals.address_families)
145 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
146 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
147 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
148 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
149 #define sctp_transport_hashtable	(sctp_globals.transport_hashtable)
150 #define sctp_checksum_disable		(sctp_globals.checksum_disable)
151 
152 /* SCTP Socket type: UDP or TCP style. */
153 enum sctp_socket_type {
154 	SCTP_SOCKET_UDP = 0,
155 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
156 	SCTP_SOCKET_TCP
157 };
158 
159 /* Per socket SCTP information. */
160 struct sctp_sock {
161 	/* inet_sock has to be the first member of sctp_sock */
162 	struct inet_sock inet;
163 	/* What kind of a socket is this? */
164 	enum sctp_socket_type type;
165 
166 	/* PF_ family specific functions.  */
167 	struct sctp_pf *pf;
168 
169 	/* Access to HMAC transform. */
170 	struct crypto_shash *hmac;
171 	char *sctp_hmac_alg;
172 
173 	/* What is our base endpointer? */
174 	struct sctp_endpoint *ep;
175 
176 	struct sctp_bind_bucket *bind_hash;
177 	/* Various Socket Options.  */
178 	__u16 default_stream;
179 	__u32 default_ppid;
180 	__u16 default_flags;
181 	__u32 default_context;
182 	__u32 default_timetolive;
183 	__u32 default_rcv_context;
184 	int max_burst;
185 
186 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
187 	 * the destination address every heartbeat interval. This value
188 	 * will be inherited by all new associations.
189 	 */
190 	__u32 hbinterval;
191 
192 	/* This is the max_retrans value for new associations. */
193 	__u16 pathmaxrxt;
194 
195 	/* The initial Path MTU to use for new associations. */
196 	__u32 pathmtu;
197 
198 	/* The default SACK delay timeout for new associations. */
199 	__u32 sackdelay;
200 	__u32 sackfreq;
201 
202 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
203 	__u32 param_flags;
204 
205 	struct sctp_initmsg initmsg;
206 	struct sctp_rtoinfo rtoinfo;
207 	struct sctp_paddrparams paddrparam;
208 	struct sctp_event_subscribe subscribe;
209 	struct sctp_assocparams assocparams;
210 
211 	int user_frag;
212 
213 	__u32 autoclose;
214 	__u32 adaptation_ind;
215 	__u32 pd_point;
216 	__u16	nodelay:1,
217 		disable_fragments:1,
218 		v4mapped:1,
219 		frag_interleave:1,
220 		strm_interleave:1,
221 		recvrcvinfo:1,
222 		recvnxtinfo:1,
223 		data_ready_signalled:1;
224 
225 	atomic_t pd_mode;
226 	/* Receive to here while partial delivery is in effect. */
227 	struct sk_buff_head pd_lobby;
228 
229 	/* These must be the last fields, as they will skipped on copies,
230 	 * like on accept and peeloff operations
231 	 */
232 	struct list_head auto_asconf_list;
233 	int do_auto_asconf;
234 };
235 
236 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
237 {
238        return (struct sctp_sock *)sk;
239 }
240 
241 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
242 {
243        return (struct sock *)sp;
244 }
245 
246 #if IS_ENABLED(CONFIG_IPV6)
247 struct sctp6_sock {
248        struct sctp_sock  sctp;
249        struct ipv6_pinfo inet6;
250 };
251 #endif /* CONFIG_IPV6 */
252 
253 
254 /* This is our APPLICATION-SPECIFIC state cookie.
255  * THIS IS NOT DICTATED BY THE SPECIFICATION.
256  */
257 /* These are the parts of an association which we send in the cookie.
258  * Most of these are straight out of:
259  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
260  *
261  */
262 
263 struct sctp_cookie {
264 
265 	/* My	       : Tag expected in every inbound packet and sent
266 	 * Verification: in the INIT or INIT ACK chunk.
267 	 * Tag	       :
268 	 */
269 	__u32 my_vtag;
270 
271 	/* Peer's      : Tag expected in every outbound packet except
272 	 * Verification: in the INIT chunk.
273 	 * Tag	       :
274 	 */
275 	__u32 peer_vtag;
276 
277 	/* The rest of these are not from the spec, but really need to
278 	 * be in the cookie.
279 	 */
280 
281 	/* My Tie Tag  : Assist in discovering a restarting association. */
282 	__u32 my_ttag;
283 
284 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
285 	__u32 peer_ttag;
286 
287 	/* When does this cookie expire? */
288 	ktime_t expiration;
289 
290 	/* Number of inbound/outbound streams which are set
291 	 * and negotiated during the INIT process.
292 	 */
293 	__u16 sinit_num_ostreams;
294 	__u16 sinit_max_instreams;
295 
296 	/* This is the first sequence number I used.  */
297 	__u32 initial_tsn;
298 
299 	/* This holds the originating address of the INIT packet.  */
300 	union sctp_addr peer_addr;
301 
302 	/* IG Section 2.35.3
303 	 * Include the source port of the INIT-ACK
304 	 */
305 	__u16		my_port;
306 
307 	__u8 prsctp_capable;
308 
309 	/* Padding for future use */
310 	__u8 padding;
311 
312 	__u32 adaptation_ind;
313 
314 	__u8 auth_random[sizeof(struct sctp_paramhdr) +
315 			 SCTP_AUTH_RANDOM_LENGTH];
316 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
317 	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
318 
319 	/* This is a shim for my peer's INIT packet, followed by
320 	 * a copy of the raw address list of the association.
321 	 * The length of the raw address list is saved in the
322 	 * raw_addr_list_len field, which will be used at the time when
323 	 * the association TCB is re-constructed from the cookie.
324 	 */
325 	__u32 raw_addr_list_len;
326 	struct sctp_init_chunk peer_init[0];
327 };
328 
329 
330 /* The format of our cookie that we send to our peer. */
331 struct sctp_signed_cookie {
332 	__u8 signature[SCTP_SECRET_SIZE];
333 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
334 	struct sctp_cookie c;
335 } __packed;
336 
337 /* This is another convenience type to allocate memory for address
338  * params for the maximum size and pass such structures around
339  * internally.
340  */
341 union sctp_addr_param {
342 	struct sctp_paramhdr p;
343 	struct sctp_ipv4addr_param v4;
344 	struct sctp_ipv6addr_param v6;
345 };
346 
347 /* A convenience type to allow walking through the various
348  * parameters and avoid casting all over the place.
349  */
350 union sctp_params {
351 	void *v;
352 	struct sctp_paramhdr *p;
353 	struct sctp_cookie_preserve_param *life;
354 	struct sctp_hostname_param *dns;
355 	struct sctp_cookie_param *cookie;
356 	struct sctp_supported_addrs_param *sat;
357 	struct sctp_ipv4addr_param *v4;
358 	struct sctp_ipv6addr_param *v6;
359 	union sctp_addr_param *addr;
360 	struct sctp_adaptation_ind_param *aind;
361 	struct sctp_supported_ext_param *ext;
362 	struct sctp_random_param *random;
363 	struct sctp_chunks_param *chunks;
364 	struct sctp_hmac_algo_param *hmac_algo;
365 	struct sctp_addip_param *addip;
366 };
367 
368 /* RFC 2960.  Section 3.3.5 Heartbeat.
369  *    Heartbeat Information: variable length
370  *    The Sender-specific Heartbeat Info field should normally include
371  *    information about the sender's current time when this HEARTBEAT
372  *    chunk is sent and the destination transport address to which this
373  *    HEARTBEAT is sent (see Section 8.3).
374  */
375 struct sctp_sender_hb_info {
376 	struct sctp_paramhdr param_hdr;
377 	union sctp_addr daddr;
378 	unsigned long sent_at;
379 	__u64 hb_nonce;
380 };
381 
382 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
383 		     gfp_t gfp);
384 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
385 void sctp_stream_free(struct sctp_stream *stream);
386 void sctp_stream_clear(struct sctp_stream *stream);
387 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
388 
389 /* What is the current SSN number for this stream? */
390 #define sctp_ssn_peek(stream, type, sid) \
391 	((stream)->type[sid].ssn)
392 
393 /* Return the next SSN number for this stream.	*/
394 #define sctp_ssn_next(stream, type, sid) \
395 	((stream)->type[sid].ssn++)
396 
397 /* Skip over this ssn and all below. */
398 #define sctp_ssn_skip(stream, type, sid, ssn) \
399 	((stream)->type[sid].ssn = ssn + 1)
400 
401 /*
402  * Pointers to address related SCTP functions.
403  * (i.e. things that depend on the address family.)
404  */
405 struct sctp_af {
406 	int		(*sctp_xmit)	(struct sk_buff *skb,
407 					 struct sctp_transport *);
408 	int		(*setsockopt)	(struct sock *sk,
409 					 int level,
410 					 int optname,
411 					 char __user *optval,
412 					 unsigned int optlen);
413 	int		(*getsockopt)	(struct sock *sk,
414 					 int level,
415 					 int optname,
416 					 char __user *optval,
417 					 int __user *optlen);
418 	int		(*compat_setsockopt)	(struct sock *sk,
419 					 int level,
420 					 int optname,
421 					 char __user *optval,
422 					 unsigned int optlen);
423 	int		(*compat_getsockopt)	(struct sock *sk,
424 					 int level,
425 					 int optname,
426 					 char __user *optval,
427 					 int __user *optlen);
428 	void		(*get_dst)	(struct sctp_transport *t,
429 					 union sctp_addr *saddr,
430 					 struct flowi *fl,
431 					 struct sock *sk);
432 	void		(*get_saddr)	(struct sctp_sock *sk,
433 					 struct sctp_transport *t,
434 					 struct flowi *fl);
435 	void		(*copy_addrlist) (struct list_head *,
436 					  struct net_device *);
437 	int		(*cmp_addr)	(const union sctp_addr *addr1,
438 					 const union sctp_addr *addr2);
439 	void		(*addr_copy)	(union sctp_addr *dst,
440 					 union sctp_addr *src);
441 	void		(*from_skb)	(union sctp_addr *,
442 					 struct sk_buff *skb,
443 					 int saddr);
444 	void		(*from_sk)	(union sctp_addr *,
445 					 struct sock *sk);
446 	void		(*from_addr_param) (union sctp_addr *,
447 					    union sctp_addr_param *,
448 					    __be16 port, int iif);
449 	int		(*to_addr_param) (const union sctp_addr *,
450 					  union sctp_addr_param *);
451 	int		(*addr_valid)	(union sctp_addr *,
452 					 struct sctp_sock *,
453 					 const struct sk_buff *);
454 	enum sctp_scope	(*scope)(union sctp_addr *);
455 	void		(*inaddr_any)	(union sctp_addr *, __be16);
456 	int		(*is_any)	(const union sctp_addr *);
457 	int		(*available)	(union sctp_addr *,
458 					 struct sctp_sock *);
459 	int		(*skb_iif)	(const struct sk_buff *sk);
460 	int		(*is_ce)	(const struct sk_buff *sk);
461 	void		(*seq_dump_addr)(struct seq_file *seq,
462 					 union sctp_addr *addr);
463 	void		(*ecn_capable)(struct sock *sk);
464 	__u16		net_header_len;
465 	int		sockaddr_len;
466 	sa_family_t	sa_family;
467 	struct list_head list;
468 };
469 
470 struct sctp_af *sctp_get_af_specific(sa_family_t);
471 int sctp_register_af(struct sctp_af *);
472 
473 /* Protocol family functions. */
474 struct sctp_pf {
475 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
476 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
477 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
478 	int  (*cmp_addr) (const union sctp_addr *,
479 			  const union sctp_addr *,
480 			  struct sctp_sock *);
481 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
482 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
483 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
484 	struct sock *(*create_accept_sk) (struct sock *sk,
485 					  struct sctp_association *asoc,
486 					  bool kern);
487 	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
488 	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
489 	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
490 	struct sctp_af *af;
491 };
492 
493 
494 /* Structure to track chunk fragments that have been acked, but peer
495  * fragments of the same message have not.
496  */
497 struct sctp_datamsg {
498 	/* Chunks waiting to be submitted to lower layer. */
499 	struct list_head chunks;
500 	/* Reference counting. */
501 	refcount_t refcnt;
502 	/* When is this message no longer interesting to the peer? */
503 	unsigned long expires_at;
504 	/* Did the messenge fail to send? */
505 	int send_error;
506 	u8 send_failed:1,
507 	   can_delay:1,	/* should this message be Nagle delayed */
508 	   abandoned:1;	/* should this message be abandoned */
509 };
510 
511 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
512 					    struct sctp_sndrcvinfo *,
513 					    struct iov_iter *);
514 void sctp_datamsg_free(struct sctp_datamsg *);
515 void sctp_datamsg_put(struct sctp_datamsg *);
516 void sctp_chunk_fail(struct sctp_chunk *, int error);
517 int sctp_chunk_abandoned(struct sctp_chunk *);
518 
519 /* RFC2960 1.4 Key Terms
520  *
521  * o Chunk: A unit of information within an SCTP packet, consisting of
522  * a chunk header and chunk-specific content.
523  *
524  * As a matter of convenience, we remember the SCTP common header for
525  * each chunk as well as a few other header pointers...
526  */
527 struct sctp_chunk {
528 	struct list_head list;
529 
530 	refcount_t refcnt;
531 
532 	/* How many times this chunk have been sent, for prsctp RTX policy */
533 	int sent_count;
534 
535 	union {
536 		/* This is our link to the per-transport transmitted list.  */
537 		struct list_head transmitted_list;
538 		/* List in specific stream outq */
539 		struct list_head stream_list;
540 	};
541 
542 	/* This field is used by chunks that hold fragmented data.
543 	 * For the first fragment this is the list that holds the rest of
544 	 * fragments. For the remaining fragments, this is the link to the
545 	 * frag_list maintained in the first fragment.
546 	 */
547 	struct list_head frag_list;
548 
549 	/* This points to the sk_buff containing the actual data.  */
550 	struct sk_buff *skb;
551 
552 	/* In case of GSO packets, this will store the head one */
553 	struct sk_buff *head_skb;
554 
555 	/* These are the SCTP headers by reverse order in a packet.
556 	 * Note that some of these may happen more than once.  In that
557 	 * case, we point at the "current" one, whatever that means
558 	 * for that level of header.
559 	 */
560 
561 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
562 	union sctp_params param_hdr;
563 	union {
564 		__u8 *v;
565 		struct sctp_datahdr *data_hdr;
566 		struct sctp_inithdr *init_hdr;
567 		struct sctp_sackhdr *sack_hdr;
568 		struct sctp_heartbeathdr *hb_hdr;
569 		struct sctp_sender_hb_info *hbs_hdr;
570 		struct sctp_shutdownhdr *shutdown_hdr;
571 		struct sctp_signed_cookie *cookie_hdr;
572 		struct sctp_ecnehdr *ecne_hdr;
573 		struct sctp_cwrhdr *ecn_cwr_hdr;
574 		struct sctp_errhdr *err_hdr;
575 		struct sctp_addiphdr *addip_hdr;
576 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
577 		struct sctp_authhdr *auth_hdr;
578 		struct sctp_idatahdr *idata_hdr;
579 	} subh;
580 
581 	__u8 *chunk_end;
582 
583 	struct sctp_chunkhdr *chunk_hdr;
584 	struct sctphdr *sctp_hdr;
585 
586 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
587 	struct sctp_sndrcvinfo sinfo;
588 
589 	/* Which association does this belong to?  */
590 	struct sctp_association *asoc;
591 
592 	/* What endpoint received this chunk? */
593 	struct sctp_ep_common *rcvr;
594 
595 	/* We fill this in if we are calculating RTT. */
596 	unsigned long sent_at;
597 
598 	/* What is the origin IP address for this chunk?  */
599 	union sctp_addr source;
600 	/* Destination address for this chunk. */
601 	union sctp_addr dest;
602 
603 	/* For outbound message, track all fragments for SEND_FAILED. */
604 	struct sctp_datamsg *msg;
605 
606 	/* For an inbound chunk, this tells us where it came from.
607 	 * For an outbound chunk, it tells us where we'd like it to
608 	 * go.	It is NULL if we have no preference.
609 	 */
610 	struct sctp_transport *transport;
611 
612 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
613 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
614 	 * spec violates the principle premis that all chunks are processed
615 	 * in order.
616 	 */
617 	struct sk_buff *auth_chunk;
618 
619 #define SCTP_CAN_FRTX 0x0
620 #define SCTP_NEED_FRTX 0x1
621 #define SCTP_DONT_FRTX 0x2
622 	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
623 		has_tsn:1,		/* Does this chunk have a TSN yet? */
624 		has_ssn:1,		/* Does this chunk have a SSN yet? */
625 		singleton:1,		/* Only chunk in the packet? */
626 		end_of_packet:1,	/* Last chunk in the packet? */
627 		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
628 		pdiscard:1,		/* Discard the whole packet now? */
629 		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
630 		data_accepted:1,	/* At least 1 chunk accepted */
631 		auth:1,			/* IN: was auth'ed | OUT: needs auth */
632 		has_asconf:1,		/* IN: have seen an asconf before */
633 		tsn_missing_report:2,	/* Data chunk missing counter. */
634 		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
635 };
636 
637 #define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
638 void sctp_chunk_hold(struct sctp_chunk *);
639 void sctp_chunk_put(struct sctp_chunk *);
640 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
641 			  struct iov_iter *from);
642 void sctp_chunk_free(struct sctp_chunk *);
643 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
644 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
645 				 const struct sctp_association *,
646 				 struct sock *, gfp_t gfp);
647 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
648 		     union sctp_addr *);
649 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
650 
651 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
652 {
653 	return ntohs(ch->subh.data_hdr->stream);
654 }
655 
656 enum {
657 	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
658 	SCTP_ADDR_SRC,		/* address can be used as source */
659 	SCTP_ADDR_DEL,		/* address about to be deleted */
660 };
661 
662 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
663 struct sctp_sockaddr_entry {
664 	struct list_head list;
665 	struct rcu_head	rcu;
666 	union sctp_addr a;
667 	__u8 state;
668 	__u8 valid;
669 };
670 
671 #define SCTP_ADDRESS_TICK_DELAY	500
672 
673 /* This structure holds lists of chunks as we are assembling for
674  * transmission.
675  */
676 struct sctp_packet {
677 	/* These are the SCTP header values (host order) for the packet. */
678 	__u16 source_port;
679 	__u16 destination_port;
680 	__u32 vtag;
681 
682 	/* This contains the payload chunks.  */
683 	struct list_head chunk_list;
684 
685 	/* This is the overhead of the sctp and ip headers. */
686 	size_t overhead;
687 	/* This is the total size of all chunks INCLUDING padding.  */
688 	size_t size;
689 	/* This is the maximum size this packet may have */
690 	size_t max_size;
691 
692 	/* The packet is destined for this transport address.
693 	 * The function we finally use to pass down to the next lower
694 	 * layer lives in the transport structure.
695 	 */
696 	struct sctp_transport *transport;
697 
698 	/* pointer to the auth chunk for this packet */
699 	struct sctp_chunk *auth;
700 
701 	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
702 	    has_sack:1,		/* This packet contains a SACK chunk. */
703 	    has_auth:1,		/* This packet contains an AUTH chunk */
704 	    has_data:1,		/* This packet contains at least 1 DATA chunk */
705 	    ipfragok:1;		/* So let ip fragment this packet */
706 };
707 
708 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
709 		      __u16 sport, __u16 dport);
710 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
711 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
712 					  struct sctp_chunk *chunk,
713 					  int one_packet, gfp_t gfp);
714 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
715 					struct sctp_chunk *chunk);
716 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
717 void sctp_packet_free(struct sctp_packet *);
718 
719 static inline int sctp_packet_empty(struct sctp_packet *packet)
720 {
721 	return packet->size == packet->overhead;
722 }
723 
724 /* This represents a remote transport address.
725  * For local transport addresses, we just use union sctp_addr.
726  *
727  * RFC2960 Section 1.4 Key Terms
728  *
729  *   o	Transport address:  A Transport Address is traditionally defined
730  *	by Network Layer address, Transport Layer protocol and Transport
731  *	Layer port number.  In the case of SCTP running over IP, a
732  *	transport address is defined by the combination of an IP address
733  *	and an SCTP port number (where SCTP is the Transport protocol).
734  *
735  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
736  *
737  *   o	The sender keeps a separate congestion control parameter set for
738  *	each of the destination addresses it can send to (not each
739  *	source-destination pair but for each destination).  The parameters
740  *	should decay if the address is not used for a long enough time
741  *	period.
742  *
743  */
744 struct sctp_transport {
745 	/* A list of transports. */
746 	struct list_head transports;
747 	struct rhlist_head node;
748 
749 	/* Reference counting. */
750 	refcount_t refcnt;
751 		/* RTO-Pending : A flag used to track if one of the DATA
752 		 *		chunks sent to this address is currently being
753 		 *		used to compute a RTT. If this flag is 0,
754 		 *		the next DATA chunk sent to this destination
755 		 *		should be used to compute a RTT and this flag
756 		 *		should be set. Every time the RTT
757 		 *		calculation completes (i.e. the DATA chunk
758 		 *		is SACK'd) clear this flag.
759 		 */
760 	__u32	rto_pending:1,
761 
762 		/*
763 		 * hb_sent : a flag that signals that we have a pending
764 		 * heartbeat.
765 		 */
766 		hb_sent:1,
767 
768 		/* Is the Path MTU update pending on this tranport */
769 		pmtu_pending:1,
770 
771 		dst_pending_confirm:1,	/* need to confirm neighbour */
772 
773 		/* Has this transport moved the ctsn since we last sacked */
774 		sack_generation:1;
775 	u32 dst_cookie;
776 
777 	struct flowi fl;
778 
779 	/* This is the peer's IP address and port. */
780 	union sctp_addr ipaddr;
781 
782 	/* These are the functions we call to handle LLP stuff.	 */
783 	struct sctp_af *af_specific;
784 
785 	/* Which association do we belong to?  */
786 	struct sctp_association *asoc;
787 
788 	/* RFC2960
789 	 *
790 	 * 12.3 Per Transport Address Data
791 	 *
792 	 * For each destination transport address in the peer's
793 	 * address list derived from the INIT or INIT ACK chunk, a
794 	 * number of data elements needs to be maintained including:
795 	 */
796 	/* RTO	       : The current retransmission timeout value.  */
797 	unsigned long rto;
798 
799 	__u32 rtt;		/* This is the most recent RTT.	 */
800 
801 	/* RTTVAR      : The current RTT variation.  */
802 	__u32 rttvar;
803 
804 	/* SRTT	       : The current smoothed round trip time.	*/
805 	__u32 srtt;
806 
807 	/*
808 	 * These are the congestion stats.
809 	 */
810 	/* cwnd	       : The current congestion window.	 */
811 	__u32 cwnd;		  /* This is the actual cwnd.  */
812 
813 	/* ssthresh    : The current slow start threshold value.  */
814 	__u32 ssthresh;
815 
816 	/* partial     : The tracking method for increase of cwnd when in
817 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
818 	 */
819 	__u32 partial_bytes_acked;
820 
821 	/* Data that has been sent, but not acknowledged. */
822 	__u32 flight_size;
823 
824 	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
825 
826 	/* Destination */
827 	struct dst_entry *dst;
828 	/* Source address. */
829 	union sctp_addr saddr;
830 
831 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
832 	 * the destination address every heartbeat interval.
833 	 */
834 	unsigned long hbinterval;
835 
836 	/* SACK delay timeout */
837 	unsigned long sackdelay;
838 	__u32 sackfreq;
839 
840 	/* When was the last time that we heard from this transport? We use
841 	 * this to pick new active and retran paths.
842 	 */
843 	ktime_t last_time_heard;
844 
845 	/* When was the last time that we sent a chunk using this
846 	 * transport? We use this to check for idle transports
847 	 */
848 	unsigned long last_time_sent;
849 
850 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
851 	 * indication based on ECNE chunk.
852 	 */
853 	unsigned long last_time_ecne_reduced;
854 
855 	/* This is the max_retrans value for the transport and will
856 	 * be initialized from the assocs value.  This can be changed
857 	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
858 	 */
859 	__u16 pathmaxrxt;
860 
861 	/* This is the partially failed retrans value for the transport
862 	 * and will be initialized from the assocs value.  This can be changed
863 	 * using the SCTP_PEER_ADDR_THLDS socket option
864 	 */
865 	int pf_retrans;
866 	/* PMTU	      : The current known path MTU.  */
867 	__u32 pathmtu;
868 
869 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
870 	__u32 param_flags;
871 
872 	/* The number of times INIT has been sent on this transport. */
873 	int init_sent_count;
874 
875 	/* state       : The current state of this destination,
876 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
877 	 */
878 	int state;
879 
880 	/* These are the error stats for this destination.  */
881 
882 	/* Error count : The current error count for this destination.	*/
883 	unsigned short error_count;
884 
885 	/* Per	       : A timer used by each destination.
886 	 * Destination :
887 	 * Timer       :
888 	 *
889 	 * [Everywhere else in the text this is called T3-rtx. -ed]
890 	 */
891 	struct timer_list T3_rtx_timer;
892 
893 	/* Heartbeat timer is per destination. */
894 	struct timer_list hb_timer;
895 
896 	/* Timer to handle ICMP proto unreachable envets */
897 	struct timer_list proto_unreach_timer;
898 
899 	/* Timer to handler reconf chunk rtx */
900 	struct timer_list reconf_timer;
901 
902 	/* Since we're using per-destination retransmission timers
903 	 * (see above), we're also using per-destination "transmitted"
904 	 * queues.  This probably ought to be a private struct
905 	 * accessible only within the outqueue, but it's not, yet.
906 	 */
907 	struct list_head transmitted;
908 
909 	/* We build bundle-able packets for this transport here.  */
910 	struct sctp_packet packet;
911 
912 	/* This is the list of transports that have chunks to send.  */
913 	struct list_head send_ready;
914 
915 	/* State information saved for SFR_CACC algorithm. The key
916 	 * idea in SFR_CACC is to maintain state at the sender on a
917 	 * per-destination basis when a changeover happens.
918 	 *	char changeover_active;
919 	 *	char cycling_changeover;
920 	 *	__u32 next_tsn_at_change;
921 	 *	char cacc_saw_newack;
922 	 */
923 	struct {
924 		/* An unsigned integer, which stores the next TSN to be
925 		 * used by the sender, at the moment of changeover.
926 		 */
927 		__u32 next_tsn_at_change;
928 
929 		/* A flag which indicates the occurrence of a changeover */
930 		char changeover_active;
931 
932 		/* A flag which indicates whether the change of primary is
933 		 * the first switch to this destination address during an
934 		 * active switch.
935 		 */
936 		char cycling_changeover;
937 
938 		/* A temporary flag, which is used during the processing of
939 		 * a SACK to estimate the causative TSN(s)'s group.
940 		 */
941 		char cacc_saw_newack;
942 	} cacc;
943 
944 	/* 64-bit random number sent with heartbeat. */
945 	__u64 hb_nonce;
946 
947 	struct rcu_head rcu;
948 };
949 
950 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
951 					  gfp_t);
952 void sctp_transport_set_owner(struct sctp_transport *,
953 			      struct sctp_association *);
954 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
955 			  struct sctp_sock *);
956 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
957 void sctp_transport_free(struct sctp_transport *);
958 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
959 void sctp_transport_reset_hb_timer(struct sctp_transport *);
960 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
961 int sctp_transport_hold(struct sctp_transport *);
962 void sctp_transport_put(struct sctp_transport *);
963 void sctp_transport_update_rto(struct sctp_transport *, __u32);
964 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
965 void sctp_transport_lower_cwnd(struct sctp_transport *t,
966 			       enum sctp_lower_cwnd reason);
967 void sctp_transport_burst_limited(struct sctp_transport *);
968 void sctp_transport_burst_reset(struct sctp_transport *);
969 unsigned long sctp_transport_timeout(struct sctp_transport *);
970 void sctp_transport_reset(struct sctp_transport *t);
971 void sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
972 void sctp_transport_immediate_rtx(struct sctp_transport *);
973 void sctp_transport_dst_release(struct sctp_transport *t);
974 void sctp_transport_dst_confirm(struct sctp_transport *t);
975 
976 
977 /* This is the structure we use to queue packets as they come into
978  * SCTP.  We write packets to it and read chunks from it.
979  */
980 struct sctp_inq {
981 	/* This is actually a queue of sctp_chunk each
982 	 * containing a partially decoded packet.
983 	 */
984 	struct list_head in_chunk_list;
985 	/* This is the packet which is currently off the in queue and is
986 	 * being worked on through the inbound chunk processing.
987 	 */
988 	struct sctp_chunk *in_progress;
989 
990 	/* This is the delayed task to finish delivering inbound
991 	 * messages.
992 	 */
993 	struct work_struct immediate;
994 };
995 
996 void sctp_inq_init(struct sctp_inq *);
997 void sctp_inq_free(struct sctp_inq *);
998 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
999 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1000 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1001 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1002 
1003 /* This is the structure we use to hold outbound chunks.  You push
1004  * chunks in and they automatically pop out the other end as bundled
1005  * packets (it calls (*output_handler)()).
1006  *
1007  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1008  * and 8.2 of the v13 draft.
1009  *
1010  * It handles retransmissions.	The connection to the timeout portion
1011  * of the state machine is through sctp_..._timeout() and timeout_handler.
1012  *
1013  * If you feed it SACKs, it will eat them.
1014  *
1015  * If you give it big chunks, it will fragment them.
1016  *
1017  * It assigns TSN's to data chunks.  This happens at the last possible
1018  * instant before transmission.
1019  *
1020  * When free()'d, it empties itself out via output_handler().
1021  */
1022 struct sctp_outq {
1023 	struct sctp_association *asoc;
1024 
1025 	/* Data pending that has never been transmitted.  */
1026 	struct list_head out_chunk_list;
1027 
1028 	/* Stream scheduler being used */
1029 	struct sctp_sched_ops *sched;
1030 
1031 	unsigned int out_qlen;	/* Total length of queued data chunks. */
1032 
1033 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1034 	unsigned int error;
1035 
1036 	/* These are control chunks we want to send.  */
1037 	struct list_head control_chunk_list;
1038 
1039 	/* These are chunks that have been sacked but are above the
1040 	 * CTSN, or cumulative tsn ack point.
1041 	 */
1042 	struct list_head sacked;
1043 
1044 	/* Put chunks on this list to schedule them for
1045 	 * retransmission.
1046 	 */
1047 	struct list_head retransmit;
1048 
1049 	/* Put chunks on this list to save them for FWD TSN processing as
1050 	 * they were abandoned.
1051 	 */
1052 	struct list_head abandoned;
1053 
1054 	/* How many unackd bytes do we have in-flight?	*/
1055 	__u32 outstanding_bytes;
1056 
1057 	/* Are we doing fast-rtx on this queue */
1058 	char fast_rtx;
1059 
1060 	/* Corked? */
1061 	char cork;
1062 };
1063 
1064 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1065 void sctp_outq_teardown(struct sctp_outq *);
1066 void sctp_outq_free(struct sctp_outq*);
1067 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1068 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1069 int sctp_outq_is_empty(const struct sctp_outq *);
1070 void sctp_outq_restart(struct sctp_outq *);
1071 
1072 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1073 		     enum sctp_retransmit_reason reason);
1074 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1075 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1076 void sctp_prsctp_prune(struct sctp_association *asoc,
1077 		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1078 /* Uncork and flush an outqueue.  */
1079 static inline void sctp_outq_cork(struct sctp_outq *q)
1080 {
1081 	q->cork = 1;
1082 }
1083 
1084 /* SCTP skb control block.
1085  * sctp_input_cb is currently used on rx and sock rx queue
1086  */
1087 struct sctp_input_cb {
1088 	union {
1089 		struct inet_skb_parm	h4;
1090 #if IS_ENABLED(CONFIG_IPV6)
1091 		struct inet6_skb_parm	h6;
1092 #endif
1093 	} header;
1094 	struct sctp_chunk *chunk;
1095 	struct sctp_af *af;
1096 };
1097 #define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1098 
1099 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1100 {
1101 	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1102 
1103 	return chunk->head_skb ? : skb;
1104 }
1105 
1106 /* These bind address data fields common between endpoints and associations */
1107 struct sctp_bind_addr {
1108 
1109 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1110 	 *
1111 	 * SCTP Port:	The local SCTP port number the endpoint is
1112 	 *		bound to.
1113 	 */
1114 	__u16 port;
1115 
1116 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1117 	 *
1118 	 * Address List: The list of IP addresses that this instance
1119 	 *	has bound.  This information is passed to one's
1120 	 *	peer(s) in INIT and INIT ACK chunks.
1121 	 */
1122 	struct list_head address_list;
1123 };
1124 
1125 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1126 void sctp_bind_addr_free(struct sctp_bind_addr *);
1127 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1128 			const struct sctp_bind_addr *src,
1129 			enum sctp_scope scope, gfp_t gfp,
1130 			int flags);
1131 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1132 			const struct sctp_bind_addr *src,
1133 			gfp_t gfp);
1134 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1135 		       int new_size, __u8 addr_state, gfp_t gfp);
1136 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1137 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1138 			 struct sctp_sock *);
1139 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1140 			 struct sctp_sock *, struct sctp_sock *);
1141 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1142 			 const union sctp_addr *addr);
1143 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1144 					const union sctp_addr	*addrs,
1145 					int			addrcnt,
1146 					struct sctp_sock	*opt);
1147 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1148 					 int *addrs_len,
1149 					 gfp_t gfp);
1150 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1151 			   __u16 port, gfp_t gfp);
1152 
1153 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1154 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1155 		  const enum sctp_scope scope);
1156 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1157 int sctp_is_ep_boundall(struct sock *sk);
1158 
1159 
1160 /* What type of endpoint?  */
1161 enum sctp_endpoint_type {
1162 	SCTP_EP_TYPE_SOCKET,
1163 	SCTP_EP_TYPE_ASSOCIATION,
1164 };
1165 
1166 /*
1167  * A common base class to bridge the implmentation view of a
1168  * socket (usually listening) endpoint versus an association's
1169  * local endpoint.
1170  * This common structure is useful for several purposes:
1171  *   1) Common interface for lookup routines.
1172  *	a) Subfunctions work for either endpoint or association
1173  *	b) Single interface to lookup allows hiding the lookup lock rather
1174  *	   than acquiring it externally.
1175  *   2) Common interface for the inbound chunk handling/state machine.
1176  *   3) Common object handling routines for reference counting, etc.
1177  *   4) Disentangle association lookup from endpoint lookup, where we
1178  *	do not have to find our endpoint to find our association.
1179  *
1180  */
1181 
1182 struct sctp_ep_common {
1183 	/* Fields to help us manage our entries in the hash tables. */
1184 	struct hlist_node node;
1185 	int hashent;
1186 
1187 	/* Runtime type information.  What kind of endpoint is this? */
1188 	enum sctp_endpoint_type type;
1189 
1190 	/* Some fields to help us manage this object.
1191 	 *   refcnt   - Reference count access to this object.
1192 	 *   dead     - Do not attempt to use this object.
1193 	 */
1194 	refcount_t    refcnt;
1195 	bool	    dead;
1196 
1197 	/* What socket does this endpoint belong to?  */
1198 	struct sock *sk;
1199 
1200 	/* This is where we receive inbound chunks.  */
1201 	struct sctp_inq	  inqueue;
1202 
1203 	/* This substructure includes the defining parameters of the
1204 	 * endpoint:
1205 	 * bind_addr.port is our shared port number.
1206 	 * bind_addr.address_list is our set of local IP addresses.
1207 	 */
1208 	struct sctp_bind_addr bind_addr;
1209 };
1210 
1211 
1212 /* RFC Section 1.4 Key Terms
1213  *
1214  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1215  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1216  *   combination of a set of eligible destination transport addresses to
1217  *   which SCTP packets can be sent and a set of eligible source
1218  *   transport addresses from which SCTP packets can be received.
1219  *   All transport addresses used by an SCTP endpoint must use the
1220  *   same port number, but can use multiple IP addresses. A transport
1221  *   address used by an SCTP endpoint must not be used by another
1222  *   SCTP endpoint. In other words, a transport address is unique
1223  *   to an SCTP endpoint.
1224  *
1225  * From an implementation perspective, each socket has one of these.
1226  * A TCP-style socket will have exactly one association on one of
1227  * these.  An UDP-style socket will have multiple associations hanging
1228  * off one of these.
1229  */
1230 
1231 struct sctp_endpoint {
1232 	/* Common substructure for endpoint and association. */
1233 	struct sctp_ep_common base;
1234 
1235 	/* Associations: A list of current associations and mappings
1236 	 *	      to the data consumers for each association. This
1237 	 *	      may be in the form of a hash table or other
1238 	 *	      implementation dependent structure. The data
1239 	 *	      consumers may be process identification
1240 	 *	      information such as file descriptors, named pipe
1241 	 *	      pointer, or table pointers dependent on how SCTP
1242 	 *	      is implemented.
1243 	 */
1244 	/* This is really a list of struct sctp_association entries. */
1245 	struct list_head asocs;
1246 
1247 	/* Secret Key: A secret key used by this endpoint to compute
1248 	 *	      the MAC.	This SHOULD be a cryptographic quality
1249 	 *	      random number with a sufficient length.
1250 	 *	      Discussion in [RFC1750] can be helpful in
1251 	 *	      selection of the key.
1252 	 */
1253 	__u8 secret_key[SCTP_SECRET_SIZE];
1254 
1255  	/* digest:  This is a digest of the sctp cookie.  This field is
1256  	 * 	    only used on the receive path when we try to validate
1257  	 * 	    that the cookie has not been tampered with.  We put
1258  	 * 	    this here so we pre-allocate this once and can re-use
1259  	 * 	    on every receive.
1260  	 */
1261  	__u8 *digest;
1262 
1263 	/* sendbuf acct. policy.	*/
1264 	__u32 sndbuf_policy;
1265 
1266 	/* rcvbuf acct. policy.	*/
1267 	__u32 rcvbuf_policy;
1268 
1269 	/* SCTP AUTH: array of the HMACs that will be allocated
1270 	 * we need this per association so that we don't serialize
1271 	 */
1272 	struct crypto_shash **auth_hmacs;
1273 
1274 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1275 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1276 
1277 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1278 	struct sctp_chunks_param *auth_chunk_list;
1279 
1280 	/* SCTP-AUTH: endpoint shared keys */
1281 	struct list_head endpoint_shared_keys;
1282 	__u16 active_key_id;
1283 	__u8  auth_enable:1,
1284 	      prsctp_enable:1,
1285 	      reconf_enable:1;
1286 
1287 	__u8  strreset_enable;
1288 };
1289 
1290 /* Recover the outter endpoint structure. */
1291 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1292 {
1293 	struct sctp_endpoint *ep;
1294 
1295 	ep = container_of(base, struct sctp_endpoint, base);
1296 	return ep;
1297 }
1298 
1299 /* These are function signatures for manipulating endpoints.  */
1300 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1301 void sctp_endpoint_free(struct sctp_endpoint *);
1302 void sctp_endpoint_put(struct sctp_endpoint *);
1303 void sctp_endpoint_hold(struct sctp_endpoint *);
1304 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1305 struct sctp_association *sctp_endpoint_lookup_assoc(
1306 	const struct sctp_endpoint *ep,
1307 	const union sctp_addr *paddr,
1308 	struct sctp_transport **);
1309 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1310 				const union sctp_addr *);
1311 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1312 					struct net *, const union sctp_addr *);
1313 int sctp_has_association(struct net *net, const union sctp_addr *laddr,
1314 			 const union sctp_addr *paddr);
1315 
1316 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1317 		     const struct sctp_association *asoc,
1318 		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1319 		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1320 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1321 		      const union sctp_addr *peer,
1322 		      struct sctp_init_chunk *init, gfp_t gfp);
1323 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1324 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1325 
1326 struct sctp_inithdr_host {
1327 	__u32 init_tag;
1328 	__u32 a_rwnd;
1329 	__u16 num_outbound_streams;
1330 	__u16 num_inbound_streams;
1331 	__u32 initial_tsn;
1332 };
1333 
1334 struct sctp_stream_priorities {
1335 	/* List of priorities scheduled */
1336 	struct list_head prio_sched;
1337 	/* List of streams scheduled */
1338 	struct list_head active;
1339 	/* The next stream stream in line */
1340 	struct sctp_stream_out_ext *next;
1341 	__u16 prio;
1342 };
1343 
1344 struct sctp_stream_out_ext {
1345 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1346 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1347 	struct list_head outq; /* chunks enqueued by this stream */
1348 	union {
1349 		struct {
1350 			/* Scheduled streams list */
1351 			struct list_head prio_list;
1352 			struct sctp_stream_priorities *prio_head;
1353 		};
1354 		/* Fields used by RR scheduler */
1355 		struct {
1356 			struct list_head rr_list;
1357 		};
1358 	};
1359 };
1360 
1361 struct sctp_stream_out {
1362 	__u16	ssn;
1363 	__u8	state;
1364 	struct sctp_stream_out_ext *ext;
1365 };
1366 
1367 struct sctp_stream_in {
1368 	__u16	ssn;
1369 };
1370 
1371 struct sctp_stream {
1372 	struct sctp_stream_out *out;
1373 	struct sctp_stream_in *in;
1374 	__u16 outcnt;
1375 	__u16 incnt;
1376 	/* Current stream being sent, if any */
1377 	struct sctp_stream_out *out_curr;
1378 	union {
1379 		/* Fields used by priority scheduler */
1380 		struct {
1381 			/* List of priorities scheduled */
1382 			struct list_head prio_list;
1383 		};
1384 		/* Fields used by RR scheduler */
1385 		struct {
1386 			/* List of streams scheduled */
1387 			struct list_head rr_list;
1388 			/* The next stream stream in line */
1389 			struct sctp_stream_out_ext *rr_next;
1390 		};
1391 	};
1392 };
1393 
1394 #define SCTP_STREAM_CLOSED		0x00
1395 #define SCTP_STREAM_OPEN		0x01
1396 
1397 /* SCTP_GET_ASSOC_STATS counters */
1398 struct sctp_priv_assoc_stats {
1399 	/* Maximum observed rto in the association during subsequent
1400 	 * observations. Value is set to 0 if no RTO measurement took place
1401 	 * The transport where the max_rto was observed is returned in
1402 	 * obs_rto_ipaddr
1403 	 */
1404 	struct sockaddr_storage obs_rto_ipaddr;
1405 	__u64 max_obs_rto;
1406 	/* Total In and Out SACKs received and sent */
1407 	__u64 isacks;
1408 	__u64 osacks;
1409 	/* Total In and Out packets received and sent */
1410 	__u64 opackets;
1411 	__u64 ipackets;
1412 	/* Total retransmitted chunks */
1413 	__u64 rtxchunks;
1414 	/* TSN received > next expected */
1415 	__u64 outofseqtsns;
1416 	/* Duplicate Chunks received */
1417 	__u64 idupchunks;
1418 	/* Gap Ack Blocks received */
1419 	__u64 gapcnt;
1420 	/* Unordered data chunks sent and received */
1421 	__u64 ouodchunks;
1422 	__u64 iuodchunks;
1423 	/* Ordered data chunks sent and received */
1424 	__u64 oodchunks;
1425 	__u64 iodchunks;
1426 	/* Control chunks sent and received */
1427 	__u64 octrlchunks;
1428 	__u64 ictrlchunks;
1429 };
1430 
1431 /* RFC2960
1432  *
1433  * 12. Recommended Transmission Control Block (TCB) Parameters
1434  *
1435  * This section details a recommended set of parameters that should
1436  * be contained within the TCB for an implementation. This section is
1437  * for illustrative purposes and should not be deemed as requirements
1438  * on an implementation or as an exhaustive list of all parameters
1439  * inside an SCTP TCB. Each implementation may need its own additional
1440  * parameters for optimization.
1441  */
1442 
1443 
1444 /* Here we have information about each individual association. */
1445 struct sctp_association {
1446 
1447 	/* A base structure common to endpoint and association.
1448 	 * In this context, it represents the associations's view
1449 	 * of the local endpoint of the association.
1450 	 */
1451 	struct sctp_ep_common base;
1452 
1453 	/* Associations on the same socket. */
1454 	struct list_head asocs;
1455 
1456 	/* association id. */
1457 	sctp_assoc_t assoc_id;
1458 
1459 	/* This is our parent endpoint.	 */
1460 	struct sctp_endpoint *ep;
1461 
1462 	/* These are those association elements needed in the cookie.  */
1463 	struct sctp_cookie c;
1464 
1465 	/* This is all information about our peer.  */
1466 	struct {
1467 		/* transport_addr_list
1468 		 *
1469 		 * Peer	       : A list of SCTP transport addresses that the
1470 		 * Transport   : peer is bound to. This information is derived
1471 		 * Address     : from the INIT or INIT ACK and is used to
1472 		 * List	       : associate an inbound packet with a given
1473 		 *	       : association. Normally this information is
1474 		 *	       : hashed or keyed for quick lookup and access
1475 		 *	       : of the TCB.
1476 		 *	       : The list is also initialized with the list
1477 		 *	       : of addresses passed with the sctp_connectx()
1478 		 *	       : call.
1479 		 *
1480 		 * It is a list of SCTP_transport's.
1481 		 */
1482 		struct list_head transport_addr_list;
1483 
1484 		/* rwnd
1485 		 *
1486 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1487 		 */
1488 		__u32 rwnd;
1489 
1490 		/* transport_count
1491 		 *
1492 		 * Peer        : A count of the number of peer addresses
1493 		 * Transport   : in the Peer Transport Address List.
1494 		 * Address     :
1495 		 * Count       :
1496 		 */
1497 		__u16 transport_count;
1498 
1499 		/* port
1500 		 *   The transport layer port number.
1501 		 */
1502 		__u16 port;
1503 
1504 		/* primary_path
1505 		 *
1506 		 * Primary     : This is the current primary destination
1507 		 * Path	       : transport address of the peer endpoint.  It
1508 		 *	       : may also specify a source transport address
1509 		 *	       : on this endpoint.
1510 		 *
1511 		 * All of these paths live on transport_addr_list.
1512 		 *
1513 		 * At the bakeoffs, we discovered that the intent of
1514 		 * primaryPath is that it only changes when the ULP
1515 		 * asks to have it changed.  We add the activePath to
1516 		 * designate the connection we are currently using to
1517 		 * transmit new data and most control chunks.
1518 		 */
1519 		struct sctp_transport *primary_path;
1520 
1521 		/* Cache the primary path address here, when we
1522 		 * need a an address for msg_name.
1523 		 */
1524 		union sctp_addr primary_addr;
1525 
1526 		/* active_path
1527 		 *   The path that we are currently using to
1528 		 *   transmit new data and most control chunks.
1529 		 */
1530 		struct sctp_transport *active_path;
1531 
1532 		/* retran_path
1533 		 *
1534 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1535 		 * ...
1536 		 * Furthermore, when its peer is multi-homed, an
1537 		 * endpoint SHOULD try to retransmit a chunk to an
1538 		 * active destination transport address that is
1539 		 * different from the last destination address to
1540 		 * which the DATA chunk was sent.
1541 		 */
1542 		struct sctp_transport *retran_path;
1543 
1544 		/* Pointer to last transport I have sent on.  */
1545 		struct sctp_transport *last_sent_to;
1546 
1547 		/* This is the last transport I have received DATA on.	*/
1548 		struct sctp_transport *last_data_from;
1549 
1550 		/*
1551 		 * Mapping  An array of bits or bytes indicating which out of
1552 		 * Array    order TSN's have been received (relative to the
1553 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1554 		 *	    order packets have been received, this array
1555 		 *	    will be set to all zero. This structure may be
1556 		 *	    in the form of a circular buffer or bit array.
1557 		 *
1558 		 * Last Rcvd   : This is the last TSN received in
1559 		 * TSN	       : sequence. This value is set initially by
1560 		 *	       : taking the peer's Initial TSN, received in
1561 		 *	       : the INIT or INIT ACK chunk, and subtracting
1562 		 *	       : one from it.
1563 		 *
1564 		 * Throughout most of the specification this is called the
1565 		 * "Cumulative TSN ACK Point".	In this case, we
1566 		 * ignore the advice in 12.2 in favour of the term
1567 		 * used in the bulk of the text.  This value is hidden
1568 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1569 		 */
1570 		struct sctp_tsnmap tsn_map;
1571 
1572 		/* This mask is used to disable sending the ASCONF chunk
1573 		 * with specified parameter to peer.
1574 		 */
1575 		__be16 addip_disabled_mask;
1576 
1577 		/* These are capabilities which our peer advertised.  */
1578 		__u8	ecn_capable:1,      /* Can peer do ECN? */
1579 			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1580 			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1581 			hostname_address:1, /* Peer understands DNS addresses? */
1582 			asconf_capable:1,   /* Does peer support ADDIP? */
1583 			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1584 			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1585 			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1586 
1587 		/* sack_needed : This flag indicates if the next received
1588 		 *             : packet is to be responded to with a
1589 		 *             : SACK. This is initialized to 0.  When a packet
1590 		 *             : is received sack_cnt is incremented. If this value
1591 		 *             : reaches 2 or more, a SACK is sent and the
1592 		 *             : value is reset to 0. Note: This is used only
1593 		 *             : when no DATA chunks are received out of
1594 		 *             : order.  When DATA chunks are out of order,
1595 		 *             : SACK's are not delayed (see Section 6).
1596 		 */
1597 		__u8    sack_needed:1,     /* Do we need to sack the peer? */
1598 			sack_generation:1,
1599 			zero_window_announced:1;
1600 		__u32	sack_cnt;
1601 
1602 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1603 
1604 		struct sctp_inithdr_host i;
1605 		void *cookie;
1606 		int cookie_len;
1607 
1608 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1609 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1610 		 * Initial TSN Value minus 1
1611 		 */
1612 		__u32 addip_serial;
1613 
1614 		/* SCTP-AUTH: We need to know pears random number, hmac list
1615 		 * and authenticated chunk list.  All that is part of the
1616 		 * cookie and these are just pointers to those locations
1617 		 */
1618 		struct sctp_random_param *peer_random;
1619 		struct sctp_chunks_param *peer_chunks;
1620 		struct sctp_hmac_algo_param *peer_hmacs;
1621 	} peer;
1622 
1623 	/* State       : A state variable indicating what state the
1624 	 *	       : association is in, i.e. COOKIE-WAIT,
1625 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1626 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1627 	 *
1628 	 *		Note: No "CLOSED" state is illustrated since if a
1629 	 *		association is "CLOSED" its TCB SHOULD be removed.
1630 	 *
1631 	 *		In this implementation we DO have a CLOSED
1632 	 *		state which is used during initiation and shutdown.
1633 	 *
1634 	 *		State takes values from SCTP_STATE_*.
1635 	 */
1636 	enum sctp_state state;
1637 
1638 	/* Overall     : The overall association error count.
1639 	 * Error Count : [Clear this any time I get something.]
1640 	 */
1641 	int overall_error_count;
1642 
1643 	/* The cookie life I award for any cookie.  */
1644 	ktime_t cookie_life;
1645 
1646 	/* These are the association's initial, max, and min RTO values.
1647 	 * These values will be initialized by system defaults, but can
1648 	 * be modified via the SCTP_RTOINFO socket option.
1649 	 */
1650 	unsigned long rto_initial;
1651 	unsigned long rto_max;
1652 	unsigned long rto_min;
1653 
1654 	/* Maximum number of new data packets that can be sent in a burst.  */
1655 	int max_burst;
1656 
1657 	/* This is the max_retrans value for the association.  This value will
1658 	 * be initialized initialized from system defaults, but can be
1659 	 * modified by the SCTP_ASSOCINFO socket option.
1660 	 */
1661 	int max_retrans;
1662 
1663 	/* This is the partially failed retrans value for the transport
1664 	 * and will be initialized from the assocs value.  This can be
1665 	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1666 	 */
1667 	int pf_retrans;
1668 
1669 	/* Maximum number of times the endpoint will retransmit INIT  */
1670 	__u16 max_init_attempts;
1671 
1672 	/* How many times have we resent an INIT? */
1673 	__u16 init_retries;
1674 
1675 	/* The largest timeout or RTO value to use in attempting an INIT */
1676 	unsigned long max_init_timeo;
1677 
1678 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1679 	 * the destination address every heartbeat interval. This value
1680 	 * will be inherited by all new transports.
1681 	 */
1682 	unsigned long hbinterval;
1683 
1684 	/* This is the max_retrans value for new transports in the
1685 	 * association.
1686 	 */
1687 	__u16 pathmaxrxt;
1688 
1689 	/* Flag that path mtu update is pending */
1690 	__u8   pmtu_pending;
1691 
1692 	/* Association : The smallest PMTU discovered for all of the
1693 	 * PMTU	       : peer's transport addresses.
1694 	 */
1695 	__u32 pathmtu;
1696 
1697 	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1698 	__u32 param_flags;
1699 
1700 	__u32 sackfreq;
1701 	/* SACK delay timeout */
1702 	unsigned long sackdelay;
1703 
1704 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1705 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1706 
1707 	/* Transport to which SHUTDOWN chunk was last sent.  */
1708 	struct sctp_transport *shutdown_last_sent_to;
1709 
1710 	/* Transport to which INIT chunk was last sent.  */
1711 	struct sctp_transport *init_last_sent_to;
1712 
1713 	/* How many times have we resent a SHUTDOWN */
1714 	int shutdown_retries;
1715 
1716 	/* Next TSN    : The next TSN number to be assigned to a new
1717 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1718 	 *	       : ACK chunk to the peer and incremented each
1719 	 *	       : time a DATA chunk is assigned a TSN
1720 	 *	       : (normally just prior to transmit or during
1721 	 *	       : fragmentation).
1722 	 */
1723 	__u32 next_tsn;
1724 
1725 	/*
1726 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1727 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1728 	 *	       : received in the INIT or INIT ACK chunk, and
1729 	 *	       : subtracting one from it.
1730 	 *
1731 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1732 	 */
1733 
1734 	__u32 ctsn_ack_point;
1735 
1736 	/* PR-SCTP Advanced.Peer.Ack.Point */
1737 	__u32 adv_peer_ack_point;
1738 
1739 	/* Highest TSN that is acknowledged by incoming SACKs. */
1740 	__u32 highest_sacked;
1741 
1742 	/* TSN marking the fast recovery exit point */
1743 	__u32 fast_recovery_exit;
1744 
1745 	/* Flag to track the current fast recovery state */
1746 	__u8 fast_recovery;
1747 
1748 	/* The number of unacknowledged data chunks.  Reported through
1749 	 * the SCTP_STATUS sockopt.
1750 	 */
1751 	__u16 unack_data;
1752 
1753 	/* The total number of data chunks that we've had to retransmit
1754 	 * as the result of a T3 timer expiration
1755 	 */
1756 	__u32 rtx_data_chunks;
1757 
1758 	/* This is the association's receive buffer space.  This value is used
1759 	 * to set a_rwnd field in an INIT or a SACK chunk.
1760 	 */
1761 	__u32 rwnd;
1762 
1763 	/* This is the last advertised value of rwnd over a SACK chunk. */
1764 	__u32 a_rwnd;
1765 
1766 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1767 	 * to slop over a maximum of the association's frag_point.
1768 	 */
1769 	__u32 rwnd_over;
1770 
1771 	/* Keeps treack of rwnd pressure.  This happens when we have
1772 	 * a window, but not recevie buffer (i.e small packets).  This one
1773 	 * is releases slowly (1 PMTU at a time ).
1774 	 */
1775 	__u32 rwnd_press;
1776 
1777 	/* This is the sndbuf size in use for the association.
1778 	 * This corresponds to the sndbuf size for the association,
1779 	 * as specified in the sk->sndbuf.
1780 	 */
1781 	int sndbuf_used;
1782 
1783 	/* This is the amount of memory that this association has allocated
1784 	 * in the receive path at any given time.
1785 	 */
1786 	atomic_t rmem_alloc;
1787 
1788 	/* This is the wait queue head for send requests waiting on
1789 	 * the association sndbuf space.
1790 	 */
1791 	wait_queue_head_t	wait;
1792 
1793 	/* The message size at which SCTP fragmentation will occur. */
1794 	__u32 frag_point;
1795 	__u32 user_frag;
1796 
1797 	/* Counter used to count INIT errors. */
1798 	int init_err_counter;
1799 
1800 	/* Count the number of INIT cycles (for doubling timeout). */
1801 	int init_cycle;
1802 
1803 	/* Default send parameters. */
1804 	__u16 default_stream;
1805 	__u16 default_flags;
1806 	__u32 default_ppid;
1807 	__u32 default_context;
1808 	__u32 default_timetolive;
1809 
1810 	/* Default receive parameters */
1811 	__u32 default_rcv_context;
1812 
1813 	/* Stream arrays */
1814 	struct sctp_stream stream;
1815 
1816 	/* All outbound chunks go through this structure.  */
1817 	struct sctp_outq outqueue;
1818 
1819 	/* A smart pipe that will handle reordering and fragmentation,
1820 	 * as well as handle passing events up to the ULP.
1821 	 */
1822 	struct sctp_ulpq ulpq;
1823 
1824 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1825 	__u32 last_ecne_tsn;
1826 
1827 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1828 	__u32 last_cwr_tsn;
1829 
1830 	/* How many duplicated TSNs have we seen?  */
1831 	int numduptsns;
1832 
1833 	/* These are to support
1834 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1835 	 *  and Enforcement of Flow and Message Limits"
1836 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1837 	 * or "ADDIP" for short.
1838 	 */
1839 
1840 
1841 
1842 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1843 	 *
1844 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1845 	 * unacknowledged at any one time.  If a sender, after sending
1846 	 * an ASCONF chunk, decides it needs to transfer another
1847 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1848 	 * returns from the previous ASCONF Chunk before sending a
1849 	 * subsequent ASCONF. Note this restriction binds each side,
1850 	 * so at any time two ASCONF may be in-transit on any given
1851 	 * association (one sent from each endpoint).
1852 	 *
1853 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1854 	 * not have an ASCONF in flight, this is NULL.]
1855 	 */
1856 	struct sctp_chunk *addip_last_asconf;
1857 
1858 	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1859 	 *
1860 	 * This is needed to implement itmes E1 - E4 of the updated
1861 	 * spec.  Here is the justification:
1862 	 *
1863 	 * Since the peer may bundle multiple ASCONF chunks toward us,
1864 	 * we now need the ability to cache multiple ACKs.  The section
1865 	 * describes in detail how they are cached and cleaned up.
1866 	 */
1867 	struct list_head asconf_ack_list;
1868 
1869 	/* These ASCONF chunks are waiting to be sent.
1870 	 *
1871 	 * These chunaks can't be pushed to outqueue until receiving
1872 	 * ASCONF_ACK for the previous ASCONF indicated by
1873 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1874 	 * is in flight at any time.
1875 	 *
1876 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1877 	 *
1878 	 * In defining the ASCONF Chunk transfer procedures, it is
1879 	 * essential that these transfers MUST NOT cause congestion
1880 	 * within the network.	To achieve this, we place these
1881 	 * restrictions on the transfer of ASCONF Chunks:
1882 	 *
1883 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1884 	 * unacknowledged at any one time.  If a sender, after sending
1885 	 * an ASCONF chunk, decides it needs to transfer another
1886 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1887 	 * returns from the previous ASCONF Chunk before sending a
1888 	 * subsequent ASCONF. Note this restriction binds each side,
1889 	 * so at any time two ASCONF may be in-transit on any given
1890 	 * association (one sent from each endpoint).
1891 	 *
1892 	 *
1893 	 * [I really think this is EXACTLY the sort of intelligence
1894 	 *  which already resides in sctp_outq.	 Please move this
1895 	 *  queue and its supporting logic down there.	--piggy]
1896 	 */
1897 	struct list_head addip_chunk_list;
1898 
1899 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1900 	 *
1901 	 * A2) A serial number should be assigned to the Chunk. The
1902 	 * serial number SHOULD be a monotonically increasing
1903 	 * number. The serial number SHOULD be initialized at
1904 	 * the start of the association to the same value as the
1905 	 * Initial TSN and every time a new ASCONF chunk is created
1906 	 * it is incremented by one after assigning the serial number
1907 	 * to the newly created chunk.
1908 	 *
1909 	 * ADDIP
1910 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1911 	 *
1912 	 * Serial Number : 32 bits (unsigned integer)
1913 	 *
1914 	 * This value represents a Serial Number for the ASCONF
1915 	 * Chunk. The valid range of Serial Number is from 0 to
1916 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1917 	 * after reaching 4294967295.
1918 	 */
1919 	__u32 addip_serial;
1920 	int src_out_of_asoc_ok;
1921 	union sctp_addr *asconf_addr_del_pending;
1922 	struct sctp_transport *new_transport;
1923 
1924 	/* SCTP AUTH: list of the endpoint shared keys.  These
1925 	 * keys are provided out of band by the user applicaton
1926 	 * and can't change during the lifetime of the association
1927 	 */
1928 	struct list_head endpoint_shared_keys;
1929 
1930 	/* SCTP AUTH:
1931 	 * The current generated assocaition shared key (secret)
1932 	 */
1933 	struct sctp_auth_bytes *asoc_shared_key;
1934 
1935 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1936 	 * that we support.
1937 	 */
1938 	__u16 default_hmac_id;
1939 
1940 	__u16 active_key_id;
1941 
1942 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
1943 	     temp:1,		/* Is it a temporary association? */
1944 	     force_delay:1,
1945 	     intl_enable:1,
1946 	     prsctp_enable:1,
1947 	     reconf_enable:1;
1948 
1949 	__u8 strreset_enable;
1950 	__u8 strreset_outstanding; /* request param count on the fly */
1951 
1952 	__u32 strreset_outseq; /* Update after receiving response */
1953 	__u32 strreset_inseq; /* Update after receiving request */
1954 	__u32 strreset_result[2]; /* save the results of last 2 responses */
1955 
1956 	struct sctp_chunk *strreset_chunk; /* save request chunk */
1957 
1958 	struct sctp_priv_assoc_stats stats;
1959 
1960 	int sent_cnt_removable;
1961 
1962 	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1963 	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1964 };
1965 
1966 
1967 /* An eyecatcher for determining if we are really looking at an
1968  * association data structure.
1969  */
1970 enum {
1971 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1972 };
1973 
1974 /* Recover the outter association structure. */
1975 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1976 {
1977 	struct sctp_association *asoc;
1978 
1979 	asoc = container_of(base, struct sctp_association, base);
1980 	return asoc;
1981 }
1982 
1983 /* These are function signatures for manipulating associations.	 */
1984 
1985 
1986 struct sctp_association *
1987 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
1988 		     enum sctp_scope scope, gfp_t gfp);
1989 void sctp_association_free(struct sctp_association *);
1990 void sctp_association_put(struct sctp_association *);
1991 void sctp_association_hold(struct sctp_association *);
1992 
1993 struct sctp_transport *sctp_assoc_choose_alter_transport(
1994 	struct sctp_association *, struct sctp_transport *);
1995 void sctp_assoc_update_retran_path(struct sctp_association *);
1996 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1997 					  const union sctp_addr *);
1998 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1999 			    const union sctp_addr *laddr);
2000 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2001 				     const union sctp_addr *address,
2002 				     const gfp_t gfp,
2003 				     const int peer_state);
2004 void sctp_assoc_del_peer(struct sctp_association *asoc,
2005 			 const union sctp_addr *addr);
2006 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2007 			 struct sctp_transport *peer);
2008 void sctp_assoc_control_transport(struct sctp_association *asoc,
2009 				  struct sctp_transport *transport,
2010 				  enum sctp_transport_cmd command,
2011 				  sctp_sn_error_t error);
2012 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2013 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
2014 					   struct net *,
2015 					   const union sctp_addr *,
2016 					   const union sctp_addr *);
2017 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2018 int sctp_assoc_update(struct sctp_association *old,
2019 		      struct sctp_association *new);
2020 
2021 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2022 
2023 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2024 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2025 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2026 void sctp_assoc_set_primary(struct sctp_association *,
2027 			    struct sctp_transport *);
2028 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2029 				    struct sctp_transport *);
2030 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2031 				     enum sctp_scope scope, gfp_t gfp);
2032 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2033 					 struct sctp_cookie*,
2034 					 gfp_t gfp);
2035 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2036 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2037 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2038 					const struct sctp_association *asoc,
2039 					__be32 serial);
2040 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2041 
2042 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2043 			const union sctp_addr *ss2);
2044 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2045 
2046 /* A convenience structure to parse out SCTP specific CMSGs. */
2047 struct sctp_cmsgs {
2048 	struct sctp_initmsg *init;
2049 	struct sctp_sndrcvinfo *srinfo;
2050 	struct sctp_sndinfo *sinfo;
2051 };
2052 
2053 /* Structure for tracking memory objects */
2054 struct sctp_dbg_objcnt_entry {
2055 	char *label;
2056 	atomic_t *counter;
2057 };
2058 
2059 #endif /* __sctp_structs_h__ */
2060