1	/* SPDX-License-Identifier: GPL-2.0-or-later */
2	/* SCTP kernel implementation
3	* (C) Copyright IBM Corp. 2001, 2004
4	* Copyright (c) 1999-2000 Cisco, Inc.
5	* Copyright (c) 1999-2001 Motorola, Inc.
6	* Copyright (c) 2001 Intel Corp.
7	*
8	* This file is part of the SCTP kernel implementation
9	*
10	* Please send any bug reports or fixes you make to the
11	* email addresses:
12	* lksctp developers <linux-sctp@vger.kernel.org>
13	*
14	* Written or modified by:
15	* Randall Stewart <randall@sctp.chicago.il.us>
16	* Ken Morneau <kmorneau@cisco.com>
17	* Qiaobing Xie <qxie1@email.mot.com>
18	* La Monte H.P. Yarroll <piggy@acm.org>
19	* Karl Knutson <karl@athena.chicago.il.us>
20	* Jon Grimm <jgrimm@us.ibm.com>
21	* Xingang Guo <xingang.guo@intel.com>
22	* Hui Huang <hui.huang@nokia.com>
23	* Sridhar Samudrala <sri@us.ibm.com>
24	* Daisy Chang <daisyc@us.ibm.com>
25	* Dajiang Zhang <dajiang.zhang@nokia.com>
26	* Ardelle Fan <ardelle.fan@intel.com>
27	* Ryan Layer <rmlayer@us.ibm.com>
28	* Anup Pemmaiah <pemmaiah@cc.usu.edu>
29	* Kevin Gao <kevin.gao@intel.com>
30	*/
31
32	#ifndef __sctp_structs_h__
33	#define __sctp_structs_h__
34
35	#include <linux/ktime.h>
36	#include <linux/generic-radix-tree.h>
37	#include <linux/rhashtable-types.h>
38	#include <linux/socket.h> /* linux/in.h needs this!! */
39	#include <linux/in.h> /* We get struct sockaddr_in. */
40	#include <linux/in6.h> /* We get struct in6_addr */
41	#include <linux/ipv6.h>
42	#include <asm/param.h> /* We get MAXHOSTNAMELEN. */
43	#include <linux/atomic.h> /* This gets us atomic counters. */
44	#include <linux/skbuff.h> /* We need sk_buff_head. */
45	#include <linux/workqueue.h> /* We need tq_struct. */
46	#include <linux/sctp.h> /* We need sctp* header structs. */
47	#include <net/sctp/auth.h> /* We need auth specific structs */
48	#include <net/ip.h> /* For inet_skb_parm */
49
50	/* A convenience structure for handling sockaddr structures.
51	* We should wean ourselves off this.
52	*/
53	union sctp_addr {
54	struct sockaddr_in v4;
55	struct sockaddr_in6 v6;
56	struct sockaddr sa;
57	};
58
59	/* Forward declarations for data structures. */
60	struct sctp_globals;
61	struct sctp_endpoint;
62	struct sctp_association;
63	struct sctp_transport;
64	struct sctp_packet;
65	struct sctp_chunk;
66	struct sctp_inq;
67	struct sctp_outq;
68	struct sctp_bind_addr;
69	struct sctp_ulpq;
70	struct sctp_ep_common;
71	struct crypto_shash;
72	struct sctp_stream;
73
74
75	#include <net/sctp/tsnmap.h>
76	#include <net/sctp/ulpevent.h>
77	#include <net/sctp/ulpqueue.h>
78	#include <net/sctp/stream_interleave.h>
79
80	/* Structures useful for managing bind/connect. */
81
82	struct sctp_bind_bucket {
83	unsigned short port;
84	signed char fastreuse;
85	signed char fastreuseport;
86	kuid_t fastuid;
87	struct hlist_node node;
88	struct hlist_head owner;
89	struct net *net;
90	};
91
92	struct sctp_bind_hashbucket {
93	spinlock_t lock;
94	struct hlist_head chain;
95	};
96
97	/* Used for hashing all associations. */
98	struct sctp_hashbucket {
99	rwlock_t lock;
100	struct hlist_head chain;
101	} __attribute__((__aligned__(8)));
102
103
104	/* The SCTP globals structure. */
105	extern struct sctp_globals {
106	/* This is a list of groups of functions for each address
107	* family that we support.
108	*/
109	struct list_head address_families;
110
111	/* This is the hash of all endpoints. */
112	struct sctp_hashbucket *ep_hashtable;
113	/* This is the sctp port control hash. */
114	struct sctp_bind_hashbucket *port_hashtable;
115	/* This is the hash of all transports. */
116	struct rhltable transport_hashtable;
117
118	/* Sizes of above hashtables. */
119	int ep_hashsize;
120	int port_hashsize;
121
122	/* Default initialization values to be applied to new associations. */
123	__u16 max_instreams;
124	__u16 max_outstreams;
125
126	/* Flag to indicate whether computing and verifying checksum
127	* is disabled. */
128	bool checksum_disable;
129	} sctp_globals;
130
131	#define sctp_max_instreams (sctp_globals.max_instreams)
132	#define sctp_max_outstreams (sctp_globals.max_outstreams)
133	#define sctp_address_families (sctp_globals.address_families)
134	#define sctp_ep_hashsize (sctp_globals.ep_hashsize)
135	#define sctp_ep_hashtable (sctp_globals.ep_hashtable)
136	#define sctp_port_hashsize (sctp_globals.port_hashsize)
137	#define sctp_port_hashtable (sctp_globals.port_hashtable)
138	#define sctp_transport_hashtable (sctp_globals.transport_hashtable)
139	#define sctp_checksum_disable (sctp_globals.checksum_disable)
140
141	/* SCTP Socket type: UDP or TCP style. */
142	enum sctp_socket_type {
143	SCTP_SOCKET_UDP = 0,
144	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
145	SCTP_SOCKET_TCP
146	};
147
148	/* Per socket SCTP information. */
149	struct sctp_sock {
150	/* inet_sock has to be the first member of sctp_sock */
151	struct inet_sock inet;
152	/* What kind of a socket is this? */
153	enum sctp_socket_type type;
154
155	/* PF_ family specific functions. */
156	struct sctp_pf *pf;
157
158	/* Access to HMAC transform. */
159	struct crypto_shash *hmac;
160	char *sctp_hmac_alg;
161
162	/* What is our base endpointer? */
163	struct sctp_endpoint *ep;
164
165	struct sctp_bind_bucket *bind_hash;
166	/* Various Socket Options. */
167	__u16 default_stream;
168	__u32 default_ppid;
169	__u16 default_flags;
170	__u32 default_context;
171	__u32 default_timetolive;
172	__u32 default_rcv_context;
173	int max_burst;
174
175	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
176	* the destination address every heartbeat interval. This value
177	* will be inherited by all new associations.
178	*/
179	__u32 hbinterval;
180	__u32 probe_interval;
181
182	__be16 udp_port;
183	__be16 encap_port;
184
185	/* This is the max_retrans value for new associations. */
186	__u16 pathmaxrxt;
187
188	__u32 flowlabel;
189	__u8 dscp;
190
191	__u16 pf_retrans;
192	__u16 ps_retrans;
193
194	/* The initial Path MTU to use for new associations. */
195	__u32 pathmtu;
196
197	/* The default SACK delay timeout for new associations. */
198	__u32 sackdelay;
199	__u32 sackfreq;
200
201	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
202	__u32 param_flags;
203
204	__u32 default_ss;
205
206	struct sctp_rtoinfo rtoinfo;
207	struct sctp_paddrparams paddrparam;
208	struct sctp_assocparams assocparams;
209
210	/*
211	* These two structures must be grouped together for the usercopy
212	* whitelist region.
213	*/
214	__u16 subscribe;
215	struct sctp_initmsg initmsg;
216
217	int user_frag;
218
219	__u32 autoclose;
220	__u32 adaptation_ind;
221	__u32 pd_point;
222	__u16 nodelay:1,
223	pf_expose:2,
224	reuse:1,
225	disable_fragments:1,
226	v4mapped:1,
227	frag_interleave:1,
228	recvrcvinfo:1,
229	recvnxtinfo:1,
230	data_ready_signalled:1;
231
232	atomic_t pd_mode;
233
234	/* Fields after this point will be skipped on copies, like on accept
235	* and peeloff operations
236	*/
237
238	/* Receive to here while partial delivery is in effect. */
239	struct sk_buff_head pd_lobby;
240
241	struct list_head auto_asconf_list;
242	int do_auto_asconf;
243	};
244
245	static inline struct sctp_sock *sctp_sk(const struct sock *sk)
246	{
247	return (struct sctp_sock *)sk;
248	}
249
250	static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
251	{
252	return (struct sock *)sp;
253	}
254
255	#if IS_ENABLED(CONFIG_IPV6)
256	struct sctp6_sock {
257	struct sctp_sock sctp;
258	struct ipv6_pinfo inet6;
259	};
260	#endif /* CONFIG_IPV6 */
261
262
263	/* This is our APPLICATION-SPECIFIC state cookie.
264	* THIS IS NOT DICTATED BY THE SPECIFICATION.
265	*/
266	/* These are the parts of an association which we send in the cookie.
267	* Most of these are straight out of:
268	* RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
269	*
270	*/
271
272	struct sctp_cookie {
273
274	/* My : Tag expected in every inbound packet and sent
275	* Verification: in the INIT or INIT ACK chunk.
276	* Tag :
277	*/
278	__u32 my_vtag;
279
280	/* Peer's : Tag expected in every outbound packet except
281	* Verification: in the INIT chunk.
282	* Tag :
283	*/
284	__u32 peer_vtag;
285
286	/* The rest of these are not from the spec, but really need to
287	* be in the cookie.
288	*/
289
290	/* My Tie Tag : Assist in discovering a restarting association. */
291	__u32 my_ttag;
292
293	/* Peer's Tie Tag: Assist in discovering a restarting association. */
294	__u32 peer_ttag;
295
296	/* When does this cookie expire? */
297	ktime_t expiration;
298
299	/* Number of inbound/outbound streams which are set
300	* and negotiated during the INIT process.
301	*/
302	__u16 sinit_num_ostreams;
303	__u16 sinit_max_instreams;
304
305	/* This is the first sequence number I used. */
306	__u32 initial_tsn;
307
308	/* This holds the originating address of the INIT packet. */
309	union sctp_addr peer_addr;
310
311	/* IG Section 2.35.3
312	* Include the source port of the INIT-ACK
313	*/
314	__u16 my_port;
315
316	__u8 prsctp_capable;
317
318	/* Padding for future use */
319	__u8 padding;
320
321	__u32 adaptation_ind;
322
323	__u8 auth_random[sizeof(struct sctp_paramhdr) +
324	SCTP_AUTH_RANDOM_LENGTH];
325	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
326	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
327
328	/* This is a shim for my peer's INIT packet, followed by
329	* a copy of the raw address list of the association.
330	* The length of the raw address list is saved in the
331	* raw_addr_list_len field, which will be used at the time when
332	* the association TCB is re-constructed from the cookie.
333	*/
334	__u32 raw_addr_list_len;
335	/* struct sctp_init_chunk peer_init[]; */
336	};
337
338
339	/* The format of our cookie that we send to our peer. */
340	struct sctp_signed_cookie {
341	__u8 signature[SCTP_SECRET_SIZE];
342	__u32 __pad; /* force sctp_cookie alignment to 64 bits */
343	struct sctp_cookie c;
344	} __packed;
345
346	/* This is another convenience type to allocate memory for address
347	* params for the maximum size and pass such structures around
348	* internally.
349	*/
350	union sctp_addr_param {
351	struct sctp_paramhdr p;
352	struct sctp_ipv4addr_param v4;
353	struct sctp_ipv6addr_param v6;
354	};
355
356	/* A convenience type to allow walking through the various
357	* parameters and avoid casting all over the place.
358	*/
359	union sctp_params {
360	void *v;
361	struct sctp_paramhdr *p;
362	struct sctp_cookie_preserve_param *life;
363	struct sctp_hostname_param *dns;
364	struct sctp_cookie_param *cookie;
365	struct sctp_supported_addrs_param *sat;
366	struct sctp_ipv4addr_param *v4;
367	struct sctp_ipv6addr_param *v6;
368	union sctp_addr_param *addr;
369	struct sctp_adaptation_ind_param *aind;
370	struct sctp_supported_ext_param *ext;
371	struct sctp_random_param *random;
372	struct sctp_chunks_param *chunks;
373	struct sctp_hmac_algo_param *hmac_algo;
374	struct sctp_addip_param *addip;
375	};
376
377	/* RFC 2960. Section 3.3.5 Heartbeat.
378	* Heartbeat Information: variable length
379	* The Sender-specific Heartbeat Info field should normally include
380	* information about the sender's current time when this HEARTBEAT
381	* chunk is sent and the destination transport address to which this
382	* HEARTBEAT is sent (see Section 8.3).
383	*/
384	struct sctp_sender_hb_info {
385	struct sctp_paramhdr param_hdr;
386	union sctp_addr daddr;
387	unsigned long sent_at;
388	__u64 hb_nonce;
389	__u32 probe_size;
390	};
391
392	int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
393	gfp_t gfp);
394	int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
395	void sctp_stream_free(struct sctp_stream *stream);
396	void sctp_stream_clear(struct sctp_stream *stream);
397	void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
398
399	/* What is the current SSN number for this stream? */
400	#define sctp_ssn_peek(stream, type, sid) \
401	(sctp_stream_##type((stream), (sid))->ssn)
402
403	/* Return the next SSN number for this stream. */
404	#define sctp_ssn_next(stream, type, sid) \
405	(sctp_stream_##type((stream), (sid))->ssn++)
406
407	/* Skip over this ssn and all below. */
408	#define sctp_ssn_skip(stream, type, sid, ssn) \
409	(sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
410
411	/* What is the current MID number for this stream? */
412	#define sctp_mid_peek(stream, type, sid) \
413	(sctp_stream_##type((stream), (sid))->mid)
414
415	/* Return the next MID number for this stream. */
416	#define sctp_mid_next(stream, type, sid) \
417	(sctp_stream_##type((stream), (sid))->mid++)
418
419	/* Skip over this mid and all below. */
420	#define sctp_mid_skip(stream, type, sid, mid) \
421	(sctp_stream_##type((stream), (sid))->mid = mid + 1)
422
423	/* What is the current MID_uo number for this stream? */
424	#define sctp_mid_uo_peek(stream, type, sid) \
425	(sctp_stream_##type((stream), (sid))->mid_uo)
426
427	/* Return the next MID_uo number for this stream. */
428	#define sctp_mid_uo_next(stream, type, sid) \
429	(sctp_stream_##type((stream), (sid))->mid_uo++)
430
431	/*
432	* Pointers to address related SCTP functions.
433	* (i.e. things that depend on the address family.)
434	*/
435	struct sctp_af {
436	int (*sctp_xmit) (struct sk_buff *skb,
437	struct sctp_transport *);
438	int (*setsockopt) (struct sock *sk,
439	int level,
440	int optname,
441	sockptr_t optval,
442	unsigned int optlen);
443	int (*getsockopt) (struct sock *sk,
444	int level,
445	int optname,
446	char __user *optval,
447	int __user *optlen);
448	void (*get_dst) (struct sctp_transport *t,
449	union sctp_addr *saddr,
450	struct flowi *fl,
451	struct sock *sk);
452	void (*get_saddr) (struct sctp_sock *sk,
453	struct sctp_transport *t,
454	struct flowi *fl);
455	void (*copy_addrlist) (struct list_head *,
456	struct net_device *);
457	int (*cmp_addr) (const union sctp_addr *addr1,
458	const union sctp_addr *addr2);
459	void (*addr_copy) (union sctp_addr *dst,
460	union sctp_addr *src);
461	void (*from_skb) (union sctp_addr *,
462	struct sk_buff *skb,
463	int saddr);
464	void (*from_sk) (union sctp_addr *,
465	struct sock *sk);
466	bool (*from_addr_param) (union sctp_addr *,
467	union sctp_addr_param *,
468	__be16 port, int iif);
469	int (*to_addr_param) (const union sctp_addr *,
470	union sctp_addr_param *);
471	int (*addr_valid) (union sctp_addr *,
472	struct sctp_sock *,
473	const struct sk_buff *);
474	enum sctp_scope (*scope)(union sctp_addr *);
475	void (*inaddr_any) (union sctp_addr *, __be16);
476	int (*is_any) (const union sctp_addr *);
477	int (*available) (union sctp_addr *,
478	struct sctp_sock *);
479	int (*skb_iif) (const struct sk_buff *sk);
480	int (*skb_sdif)(const struct sk_buff *sk);
481	int (*is_ce) (const struct sk_buff *sk);
482	void (*seq_dump_addr)(struct seq_file *seq,
483	union sctp_addr *addr);
484	void (*ecn_capable)(struct sock *sk);
485	__u16 net_header_len;
486	int sockaddr_len;
487	int (*ip_options_len)(struct sock *sk);
488	sa_family_t sa_family;
489	struct list_head list;
490	};
491
492	struct sctp_af *sctp_get_af_specific(sa_family_t);
493	int sctp_register_af(struct sctp_af *);
494
495	/* Protocol family functions. */
496	struct sctp_pf {
497	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
498	void (*skb_msgname) (struct sk_buff *, char *, int *);
499	int (*af_supported) (sa_family_t, struct sctp_sock *);
500	int (*cmp_addr) (const union sctp_addr *,
501	const union sctp_addr *,
502	struct sctp_sock *);
503	int (*bind_verify) (struct sctp_sock *, union sctp_addr *);
504	int (*send_verify) (struct sctp_sock *, union sctp_addr *);
505	int (*supported_addrs)(const struct sctp_sock *, __be16 *);
506	struct sock *(*create_accept_sk) (struct sock *sk,
507	struct sctp_association *asoc,
508	bool kern);
509	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
510	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
511	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
512	void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
513	struct sctp_af *af;
514	};
515
516
517	/* Structure to track chunk fragments that have been acked, but peer
518	* fragments of the same message have not.
519	*/
520	struct sctp_datamsg {
521	/* Chunks waiting to be submitted to lower layer. */
522	struct list_head chunks;
523	/* Reference counting. */
524	refcount_t refcnt;
525	/* When is this message no longer interesting to the peer? */
526	unsigned long expires_at;
527	/* Did the messenge fail to send? */
528	int send_error;
529	u8 send_failed:1,
530	can_delay:1, /* should this message be Nagle delayed */
531	abandoned:1; /* should this message be abandoned */
532	};
533
534	struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
535	struct sctp_sndrcvinfo *,
536	struct iov_iter *);
537	void sctp_datamsg_free(struct sctp_datamsg *);
538	void sctp_datamsg_put(struct sctp_datamsg *);
539	void sctp_chunk_fail(struct sctp_chunk *, int error);
540	int sctp_chunk_abandoned(struct sctp_chunk *);
541
542	/* RFC2960 1.4 Key Terms
543	*
544	* o Chunk: A unit of information within an SCTP packet, consisting of
545	* a chunk header and chunk-specific content.
546	*
547	* As a matter of convenience, we remember the SCTP common header for
548	* each chunk as well as a few other header pointers...
549	*/
550	struct sctp_chunk {
551	struct list_head list;
552
553	refcount_t refcnt;
554
555	/* How many times this chunk have been sent, for prsctp RTX policy */
556	int sent_count;
557
558	union {
559	/* This is our link to the per-transport transmitted list. */
560	struct list_head transmitted_list;
561	/* List in specific stream outq */
562	struct list_head stream_list;
563	};
564
565	/* This field is used by chunks that hold fragmented data.
566	* For the first fragment this is the list that holds the rest of
567	* fragments. For the remaining fragments, this is the link to the
568	* frag_list maintained in the first fragment.
569	*/
570	struct list_head frag_list;
571
572	/* This points to the sk_buff containing the actual data. */
573	struct sk_buff *skb;
574
575	union {
576	/* In case of GSO packets, this will store the head one */
577	struct sk_buff *head_skb;
578	/* In case of auth enabled, this will point to the shkey */
579	struct sctp_shared_key *shkey;
580	};
581
582	/* These are the SCTP headers by reverse order in a packet.
583	* Note that some of these may happen more than once. In that
584	* case, we point at the "current" one, whatever that means
585	* for that level of header.
586	*/
587
588	/* We point this at the FIRST TLV parameter to chunk_hdr. */
589	union sctp_params param_hdr;
590	union {
591	__u8 *v;
592	struct sctp_datahdr *data_hdr;
593	struct sctp_inithdr *init_hdr;
594	struct sctp_sackhdr *sack_hdr;
595	struct sctp_heartbeathdr *hb_hdr;
596	struct sctp_sender_hb_info *hbs_hdr;
597	struct sctp_shutdownhdr *shutdown_hdr;
598	struct sctp_signed_cookie *cookie_hdr;
599	struct sctp_ecnehdr *ecne_hdr;
600	struct sctp_cwrhdr *ecn_cwr_hdr;
601	struct sctp_errhdr *err_hdr;
602	struct sctp_addiphdr *addip_hdr;
603	struct sctp_fwdtsn_hdr *fwdtsn_hdr;
604	struct sctp_authhdr *auth_hdr;
605	struct sctp_idatahdr *idata_hdr;
606	struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
607	} subh;
608
609	__u8 *chunk_end;
610
611	struct sctp_chunkhdr *chunk_hdr;
612	struct sctphdr *sctp_hdr;
613
614	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
615	struct sctp_sndrcvinfo sinfo;
616
617	/* Which association does this belong to? */
618	struct sctp_association *asoc;
619
620	/* What endpoint received this chunk? */
621	struct sctp_ep_common *rcvr;
622
623	/* We fill this in if we are calculating RTT. */
624	unsigned long sent_at;
625
626	/* What is the origin IP address for this chunk? */
627	union sctp_addr source;
628	/* Destination address for this chunk. */
629	union sctp_addr dest;
630
631	/* For outbound message, track all fragments for SEND_FAILED. */
632	struct sctp_datamsg *msg;
633
634	/* For an inbound chunk, this tells us where it came from.
635	* For an outbound chunk, it tells us where we'd like it to
636	* go. It is NULL if we have no preference.
637	*/
638	struct sctp_transport *transport;
639
640	/* SCTP-AUTH: For the special case inbound processing of COOKIE-ECHO
641	* we need save a pointer to the AUTH chunk, since the SCTP-AUTH
642	* spec violates the principle premis that all chunks are processed
643	* in order.
644	*/
645	struct sk_buff *auth_chunk;
646
647	#define SCTP_CAN_FRTX 0x0
648	#define SCTP_NEED_FRTX 0x1
649	#define SCTP_DONT_FRTX 0x2
650	__u16 rtt_in_progress:1, /* This chunk used for RTT calc? */
651	has_tsn:1, /* Does this chunk have a TSN yet? */
652	has_ssn:1, /* Does this chunk have a SSN yet? */
653	#define has_mid has_ssn
654	singleton:1, /* Only chunk in the packet? */
655	end_of_packet:1, /* Last chunk in the packet? */
656	ecn_ce_done:1, /* Have we processed the ECN CE bit? */
657	pdiscard:1, /* Discard the whole packet now? */
658	tsn_gap_acked:1, /* Is this chunk acked by a GAP ACK? */
659	data_accepted:1, /* At least 1 chunk accepted */
660	auth:1, /* IN: was auth'ed | OUT: needs auth */
661	has_asconf:1, /* IN: have seen an asconf before */
662	pmtu_probe:1, /* Used by PLPMTUD, can be set in s HB chunk */
663	tsn_missing_report:2, /* Data chunk missing counter. */
664	fast_retransmit:2; /* Is this chunk fast retransmitted? */
665	};
666
667	#define sctp_chunk_retransmitted(chunk) (chunk->sent_count > 1)
668	void sctp_chunk_hold(struct sctp_chunk *);
669	void sctp_chunk_put(struct sctp_chunk *);
670	int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
671	struct iov_iter *from);
672	void sctp_chunk_free(struct sctp_chunk *);
673	void *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
674	struct sctp_chunk *sctp_chunkify(struct sk_buff *,
675	const struct sctp_association *,
676	struct sock *, gfp_t gfp);
677	void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
678	union sctp_addr *);
679	const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
680
681	static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
682	{
683	return ntohs(ch->subh.data_hdr->stream);
684	}
685
686	enum {
687	SCTP_ADDR_NEW, /* new address added to assoc/ep */
688	SCTP_ADDR_SRC, /* address can be used as source */
689	SCTP_ADDR_DEL, /* address about to be deleted */
690	};
691
692	/* This is a structure for holding either an IPv6 or an IPv4 address. */
693	struct sctp_sockaddr_entry {
694	struct list_head list;
695	struct rcu_head rcu;
696	union sctp_addr a;
697	__u8 state;
698	__u8 valid;
699	};
700
701	#define SCTP_ADDRESS_TICK_DELAY 500
702
703	/* This structure holds lists of chunks as we are assembling for
704	* transmission.
705	*/
706	struct sctp_packet {
707	/* These are the SCTP header values (host order) for the packet. */
708	__u16 source_port;
709	__u16 destination_port;
710	__u32 vtag;
711
712	/* This contains the payload chunks. */
713	struct list_head chunk_list;
714
715	/* This is the overhead of the sctp and ip headers. */
716	size_t overhead;
717	/* This is the total size of all chunks INCLUDING padding. */
718	size_t size;
719	/* This is the maximum size this packet may have */
720	size_t max_size;
721
722	/* The packet is destined for this transport address.
723	* The function we finally use to pass down to the next lower
724	* layer lives in the transport structure.
725	*/
726	struct sctp_transport *transport;
727
728	/* pointer to the auth chunk for this packet */
729	struct sctp_chunk *auth;
730
731	u8 has_cookie_echo:1, /* This packet contains a COOKIE-ECHO chunk. */
732	has_sack:1, /* This packet contains a SACK chunk. */
733	has_auth:1, /* This packet contains an AUTH chunk */
734	has_data:1, /* This packet contains at least 1 DATA chunk */
735	ipfragok:1; /* So let ip fragment this packet */
736	};
737
738	void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
739	__u16 sport, __u16 dport);
740	void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
741	enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
742	struct sctp_chunk *chunk,
743	int one_packet, gfp_t gfp);
744	enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
745	struct sctp_chunk *chunk);
746	int sctp_packet_transmit(struct sctp_packet *, gfp_t);
747	void sctp_packet_free(struct sctp_packet *);
748
749	static inline int sctp_packet_empty(struct sctp_packet *packet)
750	{
751	return packet->size == packet->overhead;
752	}
753
754	/* This represents a remote transport address.
755	* For local transport addresses, we just use union sctp_addr.
756	*
757	* RFC2960 Section 1.4 Key Terms
758	*
759	* o Transport address: A Transport Address is traditionally defined
760	* by Network Layer address, Transport Layer protocol and Transport
761	* Layer port number. In the case of SCTP running over IP, a
762	* transport address is defined by the combination of an IP address
763	* and an SCTP port number (where SCTP is the Transport protocol).
764	*
765	* RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
766	*
767	* o The sender keeps a separate congestion control parameter set for
768	* each of the destination addresses it can send to (not each
769	* source-destination pair but for each destination). The parameters
770	* should decay if the address is not used for a long enough time
771	* period.
772	*
773	*/
774	struct sctp_transport {
775	/* A list of transports. */
776	struct list_head transports;
777	struct rhlist_head node;
778
779	/* Reference counting. */
780	refcount_t refcnt;
781	/* RTO-Pending : A flag used to track if one of the DATA
782	* chunks sent to this address is currently being
783	* used to compute a RTT. If this flag is 0,
784	* the next DATA chunk sent to this destination
785	* should be used to compute a RTT and this flag
786	* should be set. Every time the RTT
787	* calculation completes (i.e. the DATA chunk
788	* is SACK'd) clear this flag.
789	*/
790	__u32 rto_pending:1,
791
792	/*
793	* hb_sent : a flag that signals that we have a pending
794	* heartbeat.
795	*/
796	hb_sent:1,
797
798	/* Is the Path MTU update pending on this tranport */
799	pmtu_pending:1,
800
801	dst_pending_confirm:1, /* need to confirm neighbour */
802
803	/* Has this transport moved the ctsn since we last sacked */
804	sack_generation:1;
805	u32 dst_cookie;
806
807	struct flowi fl;
808
809	/* This is the peer's IP address and port. */
810	union sctp_addr ipaddr;
811
812	/* These are the functions we call to handle LLP stuff. */
813	struct sctp_af *af_specific;
814
815	/* Which association do we belong to? */
816	struct sctp_association *asoc;
817
818	/* RFC2960
819	*
820	* 12.3 Per Transport Address Data
821	*
822	* For each destination transport address in the peer's
823	* address list derived from the INIT or INIT ACK chunk, a
824	* number of data elements needs to be maintained including:
825	*/
826	/* RTO : The current retransmission timeout value. */
827	unsigned long rto;
828
829	__u32 rtt; /* This is the most recent RTT. */
830
831	/* RTTVAR : The current RTT variation. */
832	__u32 rttvar;
833
834	/* SRTT : The current smoothed round trip time. */
835	__u32 srtt;
836
837	/*
838	* These are the congestion stats.
839	*/
840	/* cwnd : The current congestion window. */
841	__u32 cwnd; /* This is the actual cwnd. */
842
843	/* ssthresh : The current slow start threshold value. */
844	__u32 ssthresh;
845
846	/* partial : The tracking method for increase of cwnd when in
847	* bytes acked : congestion avoidance mode (see Section 6.2.2)
848	*/
849	__u32 partial_bytes_acked;
850
851	/* Data that has been sent, but not acknowledged. */
852	__u32 flight_size;
853
854	__u32 burst_limited; /* Holds old cwnd when max.burst is applied */
855
856	/* Destination */
857	struct dst_entry *dst;
858	/* Source address. */
859	union sctp_addr saddr;
860
861	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
862	* the destination address every heartbeat interval.
863	*/
864	unsigned long hbinterval;
865	unsigned long probe_interval;
866
867	/* SACK delay timeout */
868	unsigned long sackdelay;
869	__u32 sackfreq;
870
871	atomic_t mtu_info;
872
873	/* When was the last time that we heard from this transport? We use
874	* this to pick new active and retran paths.
875	*/
876	ktime_t last_time_heard;
877
878	/* When was the last time that we sent a chunk using this
879	* transport? We use this to check for idle transports
880	*/
881	unsigned long last_time_sent;
882
883	/* Last time(in jiffies) when cwnd is reduced due to the congestion
884	* indication based on ECNE chunk.
885	*/
886	unsigned long last_time_ecne_reduced;
887
888	__be16 encap_port;
889
890	/* This is the max_retrans value for the transport and will
891	* be initialized from the assocs value. This can be changed
892	* using the SCTP_SET_PEER_ADDR_PARAMS socket option.
893	*/
894	__u16 pathmaxrxt;
895
896	__u32 flowlabel;
897	__u8 dscp;
898
899	/* This is the partially failed retrans value for the transport
900	* and will be initialized from the assocs value. This can be changed
901	* using the SCTP_PEER_ADDR_THLDS socket option
902	*/
903	__u16 pf_retrans;
904	/* Used for primary path switchover. */
905	__u16 ps_retrans;
906	/* PMTU : The current known path MTU. */
907	__u32 pathmtu;
908
909	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
910	__u32 param_flags;
911
912	/* The number of times INIT has been sent on this transport. */
913	int init_sent_count;
914
915	/* state : The current state of this destination,
916	* : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
917	*/
918	int state;
919
920	/* These are the error stats for this destination. */
921
922	/* Error count : The current error count for this destination. */
923	unsigned short error_count;
924
925	/* Per : A timer used by each destination.
926	* Destination :
927	* Timer :
928	*
929	* [Everywhere else in the text this is called T3-rtx. -ed]
930	*/
931	struct timer_list T3_rtx_timer;
932
933	/* Heartbeat timer is per destination. */
934	struct timer_list hb_timer;
935
936	/* Timer to handle ICMP proto unreachable envets */
937	struct timer_list proto_unreach_timer;
938
939	/* Timer to handler reconf chunk rtx */
940	struct timer_list reconf_timer;
941
942	/* Timer to send a probe HB packet for PLPMTUD */
943	struct timer_list probe_timer;
944
945	/* Since we're using per-destination retransmission timers
946	* (see above), we're also using per-destination "transmitted"
947	* queues. This probably ought to be a private struct
948	* accessible only within the outqueue, but it's not, yet.
949	*/
950	struct list_head transmitted;
951
952	/* We build bundle-able packets for this transport here. */
953	struct sctp_packet packet;
954
955	/* This is the list of transports that have chunks to send. */
956	struct list_head send_ready;
957
958	/* State information saved for SFR_CACC algorithm. The key
959	* idea in SFR_CACC is to maintain state at the sender on a
960	* per-destination basis when a changeover happens.
961	* char changeover_active;
962	* char cycling_changeover;
963	* __u32 next_tsn_at_change;
964	* char cacc_saw_newack;
965	*/
966	struct {
967	/* An unsigned integer, which stores the next TSN to be
968	* used by the sender, at the moment of changeover.
969	*/
970	__u32 next_tsn_at_change;
971
972	/* A flag which indicates the occurrence of a changeover */
973	char changeover_active;
974
975	/* A flag which indicates whether the change of primary is
976	* the first switch to this destination address during an
977	* active switch.
978	*/
979	char cycling_changeover;
980
981	/* A temporary flag, which is used during the processing of
982	* a SACK to estimate the causative TSN(s)'s group.
983	*/
984	char cacc_saw_newack;
985	} cacc;
986
987	struct {
988	__u16 pmtu;
989	__u16 probe_size;
990	__u16 probe_high;
991	__u8 probe_count;
992	__u8 state;
993	} pl; /* plpmtud related */
994
995	/* 64-bit random number sent with heartbeat. */
996	__u64 hb_nonce;
997
998	struct rcu_head rcu;
999	};
1000
1001	struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
1002	gfp_t);
1003	void sctp_transport_set_owner(struct sctp_transport *,
1004	struct sctp_association *);
1005	void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1006	struct sctp_sock *);
1007	void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
1008	void sctp_transport_free(struct sctp_transport *);
1009	void sctp_transport_reset_t3_rtx(struct sctp_transport *);
1010	void sctp_transport_reset_hb_timer(struct sctp_transport *);
1011	void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
1012	void sctp_transport_reset_probe_timer(struct sctp_transport *transport);
1013	void sctp_transport_reset_raise_timer(struct sctp_transport *transport);
1014	int sctp_transport_hold(struct sctp_transport *);
1015	void sctp_transport_put(struct sctp_transport *);
1016	void sctp_transport_update_rto(struct sctp_transport *, __u32);
1017	void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1018	void sctp_transport_lower_cwnd(struct sctp_transport *t,
1019	enum sctp_lower_cwnd reason);
1020	void sctp_transport_burst_limited(struct sctp_transport *);
1021	void sctp_transport_burst_reset(struct sctp_transport *);
1022	unsigned long sctp_transport_timeout(struct sctp_transport *);
1023	void sctp_transport_reset(struct sctp_transport *t);
1024	bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1025	void sctp_transport_immediate_rtx(struct sctp_transport *);
1026	void sctp_transport_dst_release(struct sctp_transport *t);
1027	void sctp_transport_dst_confirm(struct sctp_transport *t);
1028	void sctp_transport_pl_send(struct sctp_transport *t);
1029	bool sctp_transport_pl_recv(struct sctp_transport *t);
1030
1031
1032	/* This is the structure we use to queue packets as they come into
1033	* SCTP. We write packets to it and read chunks from it.
1034	*/
1035	struct sctp_inq {
1036	/* This is actually a queue of sctp_chunk each
1037	* containing a partially decoded packet.
1038	*/
1039	struct list_head in_chunk_list;
1040	/* This is the packet which is currently off the in queue and is
1041	* being worked on through the inbound chunk processing.
1042	*/
1043	struct sctp_chunk *in_progress;
1044
1045	/* This is the delayed task to finish delivering inbound
1046	* messages.
1047	*/
1048	struct work_struct immediate;
1049	};
1050
1051	void sctp_inq_init(struct sctp_inq *);
1052	void sctp_inq_free(struct sctp_inq *);
1053	void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1054	struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1055	struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1056	void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1057
1058	/* This is the structure we use to hold outbound chunks. You push
1059	* chunks in and they automatically pop out the other end as bundled
1060	* packets (it calls (*output_handler)()).
1061	*
1062	* This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1063	* and 8.2 of the v13 draft.
1064	*
1065	* It handles retransmissions. The connection to the timeout portion
1066	* of the state machine is through sctp_..._timeout() and timeout_handler.
1067	*
1068	* If you feed it SACKs, it will eat them.
1069	*
1070	* If you give it big chunks, it will fragment them.
1071	*
1072	* It assigns TSN's to data chunks. This happens at the last possible
1073	* instant before transmission.
1074	*
1075	* When free()'d, it empties itself out via output_handler().
1076	*/
1077	struct sctp_outq {
1078	struct sctp_association *asoc;
1079
1080	/* Data pending that has never been transmitted. */
1081	struct list_head out_chunk_list;
1082
1083	/* Stream scheduler being used */
1084	struct sctp_sched_ops *sched;
1085
1086	unsigned int out_qlen; /* Total length of queued data chunks. */
1087
1088	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1089	unsigned int error;
1090
1091	/* These are control chunks we want to send. */
1092	struct list_head control_chunk_list;
1093
1094	/* These are chunks that have been sacked but are above the
1095	* CTSN, or cumulative tsn ack point.
1096	*/
1097	struct list_head sacked;
1098
1099	/* Put chunks on this list to schedule them for
1100	* retransmission.
1101	*/
1102	struct list_head retransmit;
1103
1104	/* Put chunks on this list to save them for FWD TSN processing as
1105	* they were abandoned.
1106	*/
1107	struct list_head abandoned;
1108
1109	/* How many unackd bytes do we have in-flight? */
1110	__u32 outstanding_bytes;
1111
1112	/* Are we doing fast-rtx on this queue */
1113	char fast_rtx;
1114
1115	/* Corked? */
1116	char cork;
1117	};
1118
1119	void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1120	void sctp_outq_teardown(struct sctp_outq *);
1121	void sctp_outq_free(struct sctp_outq*);
1122	void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1123	int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1124	int sctp_outq_is_empty(const struct sctp_outq *);
1125	void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1126	enum sctp_retransmit_reason reason);
1127	void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1128	void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1129	void sctp_prsctp_prune(struct sctp_association *asoc,
1130	struct sctp_sndrcvinfo *sinfo, int msg_len);
1131	void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1132	/* Uncork and flush an outqueue. */
1133	static inline void sctp_outq_cork(struct sctp_outq *q)
1134	{
1135	q->cork = 1;
1136	}
1137
1138	/* SCTP skb control block.
1139	* sctp_input_cb is currently used on rx and sock rx queue
1140	*/
1141	struct sctp_input_cb {
1142	union {
1143	struct inet_skb_parm h4;
1144	#if IS_ENABLED(CONFIG_IPV6)
1145	struct inet6_skb_parm h6;
1146	#endif
1147	} header;
1148	struct sctp_chunk *chunk;
1149	struct sctp_af *af;
1150	__be16 encap_port;
1151	};
1152	#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
1153
1154	struct sctp_output_cb {
1155	struct sk_buff *last;
1156	};
1157	#define SCTP_OUTPUT_CB(__skb) ((struct sctp_output_cb *)&((__skb)->cb[0]))
1158
1159	static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1160	{
1161	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1162
1163	return chunk->head_skb ? : skb;
1164	}
1165
1166	/* These bind address data fields common between endpoints and associations */
1167	struct sctp_bind_addr {
1168
1169	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1170	*
1171	* SCTP Port: The local SCTP port number the endpoint is
1172	* bound to.
1173	*/
1174	__u16 port;
1175
1176	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1177	*
1178	* Address List: The list of IP addresses that this instance
1179	* has bound. This information is passed to one's
1180	* peer(s) in INIT and INIT ACK chunks.
1181	*/
1182	struct list_head address_list;
1183	};
1184
1185	void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1186	void sctp_bind_addr_free(struct sctp_bind_addr *);
1187	int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1188	const struct sctp_bind_addr *src,
1189	enum sctp_scope scope, gfp_t gfp,
1190	int flags);
1191	int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1192	const struct sctp_bind_addr *src,
1193	gfp_t gfp);
1194	int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1195	int new_size, __u8 addr_state, gfp_t gfp);
1196	int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1197	int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1198	struct sctp_sock *);
1199	int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1200	struct sctp_sock *, struct sctp_sock *);
1201	int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1202	const union sctp_addr *addr);
1203	int sctp_bind_addrs_check(struct sctp_sock *sp,
1204	struct sctp_sock *sp2, int cnt2);
1205	union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr *bp,
1206	const union sctp_addr *addrs,
1207	int addrcnt,
1208	struct sctp_sock *opt);
1209	union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1210	int *addrs_len,
1211	gfp_t gfp);
1212	int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1213	__u16 port, gfp_t gfp);
1214
1215	enum sctp_scope sctp_scope(const union sctp_addr *addr);
1216	int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1217	const enum sctp_scope scope);
1218	int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1219	int sctp_is_ep_boundall(struct sock *sk);
1220
1221
1222	/* What type of endpoint? */
1223	enum sctp_endpoint_type {
1224	SCTP_EP_TYPE_SOCKET,
1225	SCTP_EP_TYPE_ASSOCIATION,
1226	};
1227
1228	/*
1229	* A common base class to bridge the implmentation view of a
1230	* socket (usually listening) endpoint versus an association's
1231	* local endpoint.
1232	* This common structure is useful for several purposes:
1233	* 1) Common interface for lookup routines.
1234	* a) Subfunctions work for either endpoint or association
1235	* b) Single interface to lookup allows hiding the lookup lock rather
1236	* than acquiring it externally.
1237	* 2) Common interface for the inbound chunk handling/state machine.
1238	* 3) Common object handling routines for reference counting, etc.
1239	* 4) Disentangle association lookup from endpoint lookup, where we
1240	* do not have to find our endpoint to find our association.
1241	*
1242	*/
1243
1244	struct sctp_ep_common {
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	/* Cache netns and it won't change once set */
1259	struct net *net;
1260
1261	/* This is where we receive inbound chunks. */
1262	struct sctp_inq inqueue;
1263
1264	/* This substructure includes the defining parameters of the
1265	* endpoint:
1266	* bind_addr.port is our shared port number.
1267	* bind_addr.address_list is our set of local IP addresses.
1268	*/
1269	struct sctp_bind_addr bind_addr;
1270	};
1271
1272
1273	/* RFC Section 1.4 Key Terms
1274	*
1275	* o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1276	* multi-homed host, an SCTP endpoint is represented to its peers as a
1277	* combination of a set of eligible destination transport addresses to
1278	* which SCTP packets can be sent and a set of eligible source
1279	* transport addresses from which SCTP packets can be received.
1280	* All transport addresses used by an SCTP endpoint must use the
1281	* same port number, but can use multiple IP addresses. A transport
1282	* address used by an SCTP endpoint must not be used by another
1283	* SCTP endpoint. In other words, a transport address is unique
1284	* to an SCTP endpoint.
1285	*
1286	* From an implementation perspective, each socket has one of these.
1287	* A TCP-style socket will have exactly one association on one of
1288	* these. An UDP-style socket will have multiple associations hanging
1289	* off one of these.
1290	*/
1291
1292	struct sctp_endpoint {
1293	/* Common substructure for endpoint and association. */
1294	struct sctp_ep_common base;
1295
1296	/* Fields to help us manage our entries in the hash tables. */
1297	struct hlist_node node;
1298	int hashent;
1299
1300	/* Associations: A list of current associations and mappings
1301	* to the data consumers for each association. This
1302	* may be in the form of a hash table or other
1303	* implementation dependent structure. The data
1304	* consumers may be process identification
1305	* information such as file descriptors, named pipe
1306	* pointer, or table pointers dependent on how SCTP
1307	* is implemented.
1308	*/
1309	/* This is really a list of struct sctp_association entries. */
1310	struct list_head asocs;
1311
1312	/* Secret Key: A secret key used by this endpoint to compute
1313	* the MAC. This SHOULD be a cryptographic quality
1314	* random number with a sufficient length.
1315	* Discussion in [RFC1750] can be helpful in
1316	* selection of the key.
1317	*/
1318	__u8 secret_key[SCTP_SECRET_SIZE];
1319
1320	/* digest: This is a digest of the sctp cookie. This field is
1321	* only used on the receive path when we try to validate
1322	* that the cookie has not been tampered with. We put
1323	* this here so we pre-allocate this once and can re-use
1324	* on every receive.
1325	*/
1326	__u8 *digest;
1327
1328	/* sendbuf acct. policy. */
1329	__u32 sndbuf_policy;
1330
1331	/* rcvbuf acct. policy. */
1332	__u32 rcvbuf_policy;
1333
1334	/* SCTP AUTH: array of the HMACs that will be allocated
1335	* we need this per association so that we don't serialize
1336	*/
1337	struct crypto_shash **auth_hmacs;
1338
1339	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1340	struct sctp_hmac_algo_param *auth_hmacs_list;
1341
1342	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1343	struct sctp_chunks_param *auth_chunk_list;
1344
1345	/* SCTP-AUTH: endpoint shared keys */
1346	struct list_head endpoint_shared_keys;
1347	__u16 active_key_id;
1348	__u8 ecn_enable:1,
1349	auth_enable:1,
1350	intl_enable:1,
1351	prsctp_enable:1,
1352	asconf_enable:1,
1353	reconf_enable:1;
1354
1355	__u8 strreset_enable;
1356	struct rcu_head rcu;
1357	};
1358
1359	/* Recover the outter endpoint structure. */
1360	static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1361	{
1362	struct sctp_endpoint *ep;
1363
1364	ep = container_of(base, struct sctp_endpoint, base);
1365	return ep;
1366	}
1367
1368	/* These are function signatures for manipulating endpoints. */
1369	struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1370	void sctp_endpoint_free(struct sctp_endpoint *);
1371	void sctp_endpoint_put(struct sctp_endpoint *);
1372	int sctp_endpoint_hold(struct sctp_endpoint *ep);
1373	void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1374	struct sctp_association *sctp_endpoint_lookup_assoc(
1375	const struct sctp_endpoint *ep,
1376	const union sctp_addr *paddr,
1377	struct sctp_transport **);
1378	bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1379	const union sctp_addr *paddr);
1380	struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
1381	struct net *net,
1382	const union sctp_addr *laddr,
1383	int dif, int sdif);
1384	bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1385	const union sctp_addr *paddr, int dif, int sdif);
1386
1387	int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1388	const struct sctp_association *asoc,
1389	enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1390	struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1391	int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1392	const union sctp_addr *peer,
1393	struct sctp_init_chunk *init, gfp_t gfp);
1394	__u32 sctp_generate_tag(const struct sctp_endpoint *);
1395	__u32 sctp_generate_tsn(const struct sctp_endpoint *);
1396
1397	struct sctp_inithdr_host {
1398	__u32 init_tag;
1399	__u32 a_rwnd;
1400	__u16 num_outbound_streams;
1401	__u16 num_inbound_streams;
1402	__u32 initial_tsn;
1403	};
1404
1405	struct sctp_stream_priorities {
1406	/* List of priorities scheduled */
1407	struct list_head prio_sched;
1408	/* List of streams scheduled */
1409	struct list_head active;
1410	/* The next stream in line */
1411	struct sctp_stream_out_ext *next;
1412	__u16 prio;
1413	__u16 users;
1414	};
1415
1416	struct sctp_stream_out_ext {
1417	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1418	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1419	struct list_head outq; /* chunks enqueued by this stream */
1420	union {
1421	struct {
1422	/* Scheduled streams list */
1423	struct list_head prio_list;
1424	struct sctp_stream_priorities *prio_head;
1425	};
1426	/* Fields used by RR scheduler */
1427	struct {
1428	struct list_head rr_list;
1429	};
1430	struct {
1431	struct list_head fc_list;
1432	__u32 fc_length;
1433	__u16 fc_weight;
1434	};
1435	};
1436	};
1437
1438	struct sctp_stream_out {
1439	union {
1440	__u32 mid;
1441	__u16 ssn;
1442	};
1443	__u32 mid_uo;
1444	struct sctp_stream_out_ext *ext;
1445	__u8 state;
1446	};
1447
1448	struct sctp_stream_in {
1449	union {
1450	__u32 mid;
1451	__u16 ssn;
1452	};
1453	__u32 mid_uo;
1454	__u32 fsn;
1455	__u32 fsn_uo;
1456	char pd_mode;
1457	char pd_mode_uo;
1458	};
1459
1460	struct sctp_stream {
1461	GENRADIX(struct sctp_stream_out) out;
1462	GENRADIX(struct sctp_stream_in) in;
1463
1464	__u16 outcnt;
1465	__u16 incnt;
1466	/* Current stream being sent, if any */
1467	struct sctp_stream_out *out_curr;
1468	union {
1469	/* Fields used by priority scheduler */
1470	struct {
1471	/* List of priorities scheduled */
1472	struct list_head prio_list;
1473	};
1474	/* Fields used by RR scheduler */
1475	struct {
1476	/* List of streams scheduled */
1477	struct list_head rr_list;
1478	/* The next stream in line */
1479	struct sctp_stream_out_ext *rr_next;
1480	};
1481	struct {
1482	struct list_head fc_list;
1483	};
1484	};
1485	struct sctp_stream_interleave *si;
1486	};
1487
1488	static inline struct sctp_stream_out *sctp_stream_out(
1489	struct sctp_stream *stream,
1490	__u16 sid)
1491	{
1492	return genradix_ptr(&stream->out, sid);
1493	}
1494
1495	static inline struct sctp_stream_in *sctp_stream_in(
1496	struct sctp_stream *stream,
1497	__u16 sid)
1498	{
1499	return genradix_ptr(&stream->in, sid);
1500	}
1501
1502	#define SCTP_SO(s, i) sctp_stream_out((s), (i))
1503	#define SCTP_SI(s, i) sctp_stream_in((s), (i))
1504
1505	#define SCTP_STREAM_CLOSED 0x00
1506	#define SCTP_STREAM_OPEN 0x01
1507
1508	static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1509	{
1510	return stream->si->data_chunk_len;
1511	}
1512
1513	static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1514	{
1515	return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1516	}
1517
1518	static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1519	{
1520	return stream->si->ftsn_chunk_len;
1521	}
1522
1523	static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1524	{
1525	return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1526	}
1527
1528	/* SCTP_GET_ASSOC_STATS counters */
1529	struct sctp_priv_assoc_stats {
1530	/* Maximum observed rto in the association during subsequent
1531	* observations. Value is set to 0 if no RTO measurement took place
1532	* The transport where the max_rto was observed is returned in
1533	* obs_rto_ipaddr
1534	*/
1535	struct sockaddr_storage obs_rto_ipaddr;
1536	__u64 max_obs_rto;
1537	/* Total In and Out SACKs received and sent */
1538	__u64 isacks;
1539	__u64 osacks;
1540	/* Total In and Out packets received and sent */
1541	__u64 opackets;
1542	__u64 ipackets;
1543	/* Total retransmitted chunks */
1544	__u64 rtxchunks;
1545	/* TSN received > next expected */
1546	__u64 outofseqtsns;
1547	/* Duplicate Chunks received */
1548	__u64 idupchunks;
1549	/* Gap Ack Blocks received */
1550	__u64 gapcnt;
1551	/* Unordered data chunks sent and received */
1552	__u64 ouodchunks;
1553	__u64 iuodchunks;
1554	/* Ordered data chunks sent and received */
1555	__u64 oodchunks;
1556	__u64 iodchunks;
1557	/* Control chunks sent and received */
1558	__u64 octrlchunks;
1559	__u64 ictrlchunks;
1560	};
1561
1562	/* RFC2960
1563	*
1564	* 12. Recommended Transmission Control Block (TCB) Parameters
1565	*
1566	* This section details a recommended set of parameters that should
1567	* be contained within the TCB for an implementation. This section is
1568	* for illustrative purposes and should not be deemed as requirements
1569	* on an implementation or as an exhaustive list of all parameters
1570	* inside an SCTP TCB. Each implementation may need its own additional
1571	* parameters for optimization.
1572	*/
1573
1574
1575	/* Here we have information about each individual association. */
1576	struct sctp_association {
1577
1578	/* A base structure common to endpoint and association.
1579	* In this context, it represents the associations's view
1580	* of the local endpoint of the association.
1581	*/
1582	struct sctp_ep_common base;
1583
1584	/* Associations on the same socket. */
1585	struct list_head asocs;
1586
1587	/* association id. */
1588	sctp_assoc_t assoc_id;
1589
1590	/* This is our parent endpoint. */
1591	struct sctp_endpoint *ep;
1592
1593	/* These are those association elements needed in the cookie. */
1594	struct sctp_cookie c;
1595
1596	/* This is all information about our peer. */
1597	struct {
1598	/* transport_addr_list
1599	*
1600	* Peer : A list of SCTP transport addresses that the
1601	* Transport : peer is bound to. This information is derived
1602	* Address : from the INIT or INIT ACK and is used to
1603	* List : associate an inbound packet with a given
1604	* : association. Normally this information is
1605	* : hashed or keyed for quick lookup and access
1606	* : of the TCB.
1607	* : The list is also initialized with the list
1608	* : of addresses passed with the sctp_connectx()
1609	* : call.
1610	*
1611	* It is a list of SCTP_transport's.
1612	*/
1613	struct list_head transport_addr_list;
1614
1615	/* rwnd
1616	*
1617	* Peer Rwnd : Current calculated value of the peer's rwnd.
1618	*/
1619	__u32 rwnd;
1620
1621	/* transport_count
1622	*
1623	* Peer : A count of the number of peer addresses
1624	* Transport : in the Peer Transport Address List.
1625	* Address :
1626	* Count :
1627	*/
1628	__u16 transport_count;
1629
1630	/* port
1631	* The transport layer port number.
1632	*/
1633	__u16 port;
1634
1635	/* primary_path
1636	*
1637	* Primary : This is the current primary destination
1638	* Path : transport address of the peer endpoint. It
1639	* : may also specify a source transport address
1640	* : on this endpoint.
1641	*
1642	* All of these paths live on transport_addr_list.
1643	*
1644	* At the bakeoffs, we discovered that the intent of
1645	* primaryPath is that it only changes when the ULP
1646	* asks to have it changed. We add the activePath to
1647	* designate the connection we are currently using to
1648	* transmit new data and most control chunks.
1649	*/
1650	struct sctp_transport *primary_path;
1651
1652	/* Cache the primary path address here, when we
1653	* need a an address for msg_name.
1654	*/
1655	union sctp_addr primary_addr;
1656
1657	/* active_path
1658	* The path that we are currently using to
1659	* transmit new data and most control chunks.
1660	*/
1661	struct sctp_transport *active_path;
1662
1663	/* retran_path
1664	*
1665	* RFC2960 6.4 Multi-homed SCTP Endpoints
1666	* ...
1667	* Furthermore, when its peer is multi-homed, an
1668	* endpoint SHOULD try to retransmit a chunk to an
1669	* active destination transport address that is
1670	* different from the last destination address to
1671	* which the DATA chunk was sent.
1672	*/
1673	struct sctp_transport *retran_path;
1674
1675	/* Pointer to last transport I have sent on. */
1676	struct sctp_transport *last_sent_to;
1677
1678	/* This is the last transport I have received DATA on. */
1679	struct sctp_transport *last_data_from;
1680
1681	/*
1682	* Mapping An array of bits or bytes indicating which out of
1683	* Array order TSN's have been received (relative to the
1684	* Last Rcvd TSN). If no gaps exist, i.e. no out of
1685	* order packets have been received, this array
1686	* will be set to all zero. This structure may be
1687	* in the form of a circular buffer or bit array.
1688	*
1689	* Last Rcvd : This is the last TSN received in
1690	* TSN : sequence. This value is set initially by
1691	* : taking the peer's Initial TSN, received in
1692	* : the INIT or INIT ACK chunk, and subtracting
1693	* : one from it.
1694	*
1695	* Throughout most of the specification this is called the
1696	* "Cumulative TSN ACK Point". In this case, we
1697	* ignore the advice in 12.2 in favour of the term
1698	* used in the bulk of the text. This value is hidden
1699	* in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1700	*/
1701	struct sctp_tsnmap tsn_map;
1702
1703	/* This mask is used to disable sending the ASCONF chunk
1704	* with specified parameter to peer.
1705	*/
1706	__be16 addip_disabled_mask;
1707
1708	/* These are capabilities which our peer advertised. */
1709	__u16 ecn_capable:1, /* Can peer do ECN? */
1710	ipv4_address:1, /* Peer understands IPv4 addresses? */
1711	ipv6_address:1, /* Peer understands IPv6 addresses? */
1712	asconf_capable:1, /* Does peer support ADDIP? */
1713	prsctp_capable:1, /* Can peer do PR-SCTP? */
1714	reconf_capable:1, /* Can peer do RE-CONFIG? */
1715	intl_capable:1, /* Can peer do INTERLEAVE */
1716	auth_capable:1, /* Is peer doing SCTP-AUTH? */
1717	/* sack_needed:
1718	* This flag indicates if the next received
1719	* packet is to be responded to with a
1720	* SACK. This is initialized to 0. When a packet
1721	* is received sack_cnt is incremented. If this value
1722	* reaches 2 or more, a SACK is sent and the
1723	* value is reset to 0. Note: This is used only
1724	* when no DATA chunks are received out of
1725	* order. When DATA chunks are out of order,
1726	* SACK's are not delayed (see Section 6).
1727	*/
1728	sack_needed:1, /* Do we need to sack the peer? */
1729	sack_generation:1,
1730	zero_window_announced:1;
1731
1732	__u32 sack_cnt;
1733
1734	__u32 adaptation_ind; /* Adaptation Code point. */
1735
1736	struct sctp_inithdr_host i;
1737	void *cookie;
1738	int cookie_len;
1739
1740	/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1741	* C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1742	* Initial TSN Value minus 1
1743	*/
1744	__u32 addip_serial;
1745
1746	/* SCTP-AUTH: We need to know pears random number, hmac list
1747	* and authenticated chunk list. All that is part of the
1748	* cookie and these are just pointers to those locations
1749	*/
1750	struct sctp_random_param *peer_random;
1751	struct sctp_chunks_param *peer_chunks;
1752	struct sctp_hmac_algo_param *peer_hmacs;
1753	} peer;
1754
1755	/* State : A state variable indicating what state the
1756	* : association is in, i.e. COOKIE-WAIT,
1757	* : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1758	* : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1759	*
1760	* Note: No "CLOSED" state is illustrated since if a
1761	* association is "CLOSED" its TCB SHOULD be removed.
1762	*
1763	* In this implementation we DO have a CLOSED
1764	* state which is used during initiation and shutdown.
1765	*
1766	* State takes values from SCTP_STATE_*.
1767	*/
1768	enum sctp_state state;
1769
1770	/* Overall : The overall association error count.
1771	* Error Count : [Clear this any time I get something.]
1772	*/
1773	int overall_error_count;
1774
1775	/* The cookie life I award for any cookie. */
1776	ktime_t cookie_life;
1777
1778	/* These are the association's initial, max, and min RTO values.
1779	* These values will be initialized by system defaults, but can
1780	* be modified via the SCTP_RTOINFO socket option.
1781	*/
1782	unsigned long rto_initial;
1783	unsigned long rto_max;
1784	unsigned long rto_min;
1785
1786	/* Maximum number of new data packets that can be sent in a burst. */
1787	int max_burst;
1788
1789	/* This is the max_retrans value for the association. This value will
1790	* be initialized from system defaults, but can be
1791	* modified by the SCTP_ASSOCINFO socket option.
1792	*/
1793	int max_retrans;
1794
1795	/* This is the partially failed retrans value for the transport
1796	* and will be initialized from the assocs value. This can be
1797	* changed using the SCTP_PEER_ADDR_THLDS socket option
1798	*/
1799	__u16 pf_retrans;
1800	/* Used for primary path switchover. */
1801	__u16 ps_retrans;
1802
1803	/* Maximum number of times the endpoint will retransmit INIT */
1804	__u16 max_init_attempts;
1805
1806	/* How many times have we resent an INIT? */
1807	__u16 init_retries;
1808
1809	/* The largest timeout or RTO value to use in attempting an INIT */
1810	unsigned long max_init_timeo;
1811
1812	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1813	* the destination address every heartbeat interval. This value
1814	* will be inherited by all new transports.
1815	*/
1816	unsigned long hbinterval;
1817	unsigned long probe_interval;
1818
1819	__be16 encap_port;
1820
1821	/* This is the max_retrans value for new transports in the
1822	* association.
1823	*/
1824	__u16 pathmaxrxt;
1825
1826	__u32 flowlabel;
1827	__u8 dscp;
1828
1829	/* Flag that path mtu update is pending */
1830	__u8 pmtu_pending;
1831
1832	/* Association : The smallest PMTU discovered for all of the
1833	* PMTU : peer's transport addresses.
1834	*/
1835	__u32 pathmtu;
1836
1837	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1838	__u32 param_flags;
1839
1840	__u32 sackfreq;
1841	/* SACK delay timeout */
1842	unsigned long sackdelay;
1843
1844	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1845	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1846
1847	/* Transport to which SHUTDOWN chunk was last sent. */
1848	struct sctp_transport *shutdown_last_sent_to;
1849
1850	/* Transport to which INIT chunk was last sent. */
1851	struct sctp_transport *init_last_sent_to;
1852
1853	/* How many times have we resent a SHUTDOWN */
1854	int shutdown_retries;
1855
1856	/* Next TSN : The next TSN number to be assigned to a new
1857	* : DATA chunk. This is sent in the INIT or INIT
1858	* : ACK chunk to the peer and incremented each
1859	* : time a DATA chunk is assigned a TSN
1860	* : (normally just prior to transmit or during
1861	* : fragmentation).
1862	*/
1863	__u32 next_tsn;
1864
1865	/*
1866	* Last Rcvd : This is the last TSN received in sequence. This value
1867	* TSN : is set initially by taking the peer's Initial TSN,
1868	* : received in the INIT or INIT ACK chunk, and
1869	* : subtracting one from it.
1870	*
1871	* Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1872	*/
1873
1874	__u32 ctsn_ack_point;
1875
1876	/* PR-SCTP Advanced.Peer.Ack.Point */
1877	__u32 adv_peer_ack_point;
1878
1879	/* Highest TSN that is acknowledged by incoming SACKs. */
1880	__u32 highest_sacked;
1881
1882	/* TSN marking the fast recovery exit point */
1883	__u32 fast_recovery_exit;
1884
1885	/* Flag to track the current fast recovery state */
1886	__u8 fast_recovery;
1887
1888	/* The number of unacknowledged data chunks. Reported through
1889	* the SCTP_STATUS sockopt.
1890	*/
1891	__u16 unack_data;
1892
1893	/* The total number of data chunks that we've had to retransmit
1894	* as the result of a T3 timer expiration
1895	*/
1896	__u32 rtx_data_chunks;
1897
1898	/* This is the association's receive buffer space. This value is used
1899	* to set a_rwnd field in an INIT or a SACK chunk.
1900	*/
1901	__u32 rwnd;
1902
1903	/* This is the last advertised value of rwnd over a SACK chunk. */
1904	__u32 a_rwnd;
1905
1906	/* Number of bytes by which the rwnd has slopped. The rwnd is allowed
1907	* to slop over a maximum of the association's frag_point.
1908	*/
1909	__u32 rwnd_over;
1910
1911	/* Keeps treack of rwnd pressure. This happens when we have
1912	* a window, but not recevie buffer (i.e small packets). This one
1913	* is releases slowly (1 PMTU at a time ).
1914	*/
1915	__u32 rwnd_press;
1916
1917	/* This is the sndbuf size in use for the association.
1918	* This corresponds to the sndbuf size for the association,
1919	* as specified in the sk->sndbuf.
1920	*/
1921	int sndbuf_used;
1922
1923	/* This is the amount of memory that this association has allocated
1924	* in the receive path at any given time.
1925	*/
1926	atomic_t rmem_alloc;
1927
1928	/* This is the wait queue head for send requests waiting on
1929	* the association sndbuf space.
1930	*/
1931	wait_queue_head_t wait;
1932
1933	/* The message size at which SCTP fragmentation will occur. */
1934	__u32 frag_point;
1935	__u32 user_frag;
1936
1937	/* Counter used to count INIT errors. */
1938	int init_err_counter;
1939
1940	/* Count the number of INIT cycles (for doubling timeout). */
1941	int init_cycle;
1942
1943	/* Default send parameters. */
1944	__u16 default_stream;
1945	__u16 default_flags;
1946	__u32 default_ppid;
1947	__u32 default_context;
1948	__u32 default_timetolive;
1949
1950	/* Default receive parameters */
1951	__u32 default_rcv_context;
1952
1953	/* Stream arrays */
1954	struct sctp_stream stream;
1955
1956	/* All outbound chunks go through this structure. */
1957	struct sctp_outq outqueue;
1958
1959	/* A smart pipe that will handle reordering and fragmentation,
1960	* as well as handle passing events up to the ULP.
1961	*/
1962	struct sctp_ulpq ulpq;
1963
1964	/* Last TSN that caused an ECNE Chunk to be sent. */
1965	__u32 last_ecne_tsn;
1966
1967	/* Last TSN that caused a CWR Chunk to be sent. */
1968	__u32 last_cwr_tsn;
1969
1970	/* How many duplicated TSNs have we seen? */
1971	int numduptsns;
1972
1973	/* These are to support
1974	* "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1975	* and Enforcement of Flow and Message Limits"
1976	* <draft-ietf-tsvwg-addip-sctp-02.txt>
1977	* or "ADDIP" for short.
1978	*/
1979
1980
1981
1982	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1983	*
1984	* R1) One and only one ASCONF Chunk MAY be in transit and
1985	* unacknowledged at any one time. If a sender, after sending
1986	* an ASCONF chunk, decides it needs to transfer another
1987	* ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1988	* returns from the previous ASCONF Chunk before sending a
1989	* subsequent ASCONF. Note this restriction binds each side,
1990	* so at any time two ASCONF may be in-transit on any given
1991	* association (one sent from each endpoint).
1992	*
1993	* [This is our one-and-only-one ASCONF in flight. If we do
1994	* not have an ASCONF in flight, this is NULL.]
1995	*/
1996	struct sctp_chunk *addip_last_asconf;
1997
1998	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1999	*
2000	* This is needed to implement itmes E1 - E4 of the updated
2001	* spec. Here is the justification:
2002	*
2003	* Since the peer may bundle multiple ASCONF chunks toward us,
2004	* we now need the ability to cache multiple ACKs. The section
2005	* describes in detail how they are cached and cleaned up.
2006	*/
2007	struct list_head asconf_ack_list;
2008
2009	/* These ASCONF chunks are waiting to be sent.
2010	*
2011	* These chunaks can't be pushed to outqueue until receiving
2012	* ASCONF_ACK for the previous ASCONF indicated by
2013	* addip_last_asconf, so as to guarantee that only one ASCONF
2014	* is in flight at any time.
2015	*
2016	* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
2017	*
2018	* In defining the ASCONF Chunk transfer procedures, it is
2019	* essential that these transfers MUST NOT cause congestion
2020	* within the network. To achieve this, we place these
2021	* restrictions on the transfer of ASCONF Chunks:
2022	*
2023	* R1) One and only one ASCONF Chunk MAY be in transit and
2024	* unacknowledged at any one time. If a sender, after sending
2025	* an ASCONF chunk, decides it needs to transfer another
2026	* ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
2027	* returns from the previous ASCONF Chunk before sending a
2028	* subsequent ASCONF. Note this restriction binds each side,
2029	* so at any time two ASCONF may be in-transit on any given
2030	* association (one sent from each endpoint).
2031	*
2032	*
2033	* [I really think this is EXACTLY the sort of intelligence
2034	* which already resides in sctp_outq. Please move this
2035	* queue and its supporting logic down there. --piggy]
2036	*/
2037	struct list_head addip_chunk_list;
2038
2039	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2040	*
2041	* A2) A serial number should be assigned to the Chunk. The
2042	* serial number SHOULD be a monotonically increasing
2043	* number. The serial number SHOULD be initialized at
2044	* the start of the association to the same value as the
2045	* Initial TSN and every time a new ASCONF chunk is created
2046	* it is incremented by one after assigning the serial number
2047	* to the newly created chunk.
2048	*
2049	* ADDIP
2050	* 3.1.1 Address/Stream Configuration Change Chunk (ASCONF)
2051	*
2052	* Serial Number : 32 bits (unsigned integer)
2053	*
2054	* This value represents a Serial Number for the ASCONF
2055	* Chunk. The valid range of Serial Number is from 0 to
2056	* 4294967295 (2^32 - 1). Serial Numbers wrap back to 0
2057	* after reaching 4294967295.
2058	*/
2059	__u32 addip_serial;
2060	int src_out_of_asoc_ok;
2061	union sctp_addr *asconf_addr_del_pending;
2062	struct sctp_transport *new_transport;
2063
2064	/* SCTP AUTH: list of the endpoint shared keys. These
2065	* keys are provided out of band by the user applicaton
2066	* and can't change during the lifetime of the association
2067	*/
2068	struct list_head endpoint_shared_keys;
2069
2070	/* SCTP AUTH:
2071	* The current generated assocaition shared key (secret)
2072	*/
2073	struct sctp_auth_bytes *asoc_shared_key;
2074	struct sctp_shared_key *shkey;
2075
2076	/* SCTP AUTH: hmac id of the first peer requested algorithm
2077	* that we support.
2078	*/
2079	__u16 default_hmac_id;
2080
2081	__u16 active_key_id;
2082
2083	__u8 need_ecne:1, /* Need to send an ECNE Chunk? */
2084	temp:1, /* Is it a temporary association? */
2085	pf_expose:2, /* Expose pf state? */
2086	force_delay:1;
2087
2088	__u8 strreset_enable;
2089	__u8 strreset_outstanding; /* request param count on the fly */
2090
2091	__u32 strreset_outseq; /* Update after receiving response */
2092	__u32 strreset_inseq; /* Update after receiving request */
2093	__u32 strreset_result[2]; /* save the results of last 2 responses */
2094
2095	struct sctp_chunk *strreset_chunk; /* save request chunk */
2096
2097	struct sctp_priv_assoc_stats stats;
2098
2099	int sent_cnt_removable;
2100
2101	__u16 subscribe;
2102
2103	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2104	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2105
2106	/* Security identifiers from incoming (INIT). These are set by
2107	* security_sctp_assoc_request(). These will only be used by
2108	* SCTP TCP type sockets and peeled off connections as they
2109	* cause a new socket to be generated. security_sctp_sk_clone()
2110	* will then plug these into the new socket.
2111	*/
2112
2113	u32 secid;
2114	u32 peer_secid;
2115
2116	struct rcu_head rcu;
2117	};
2118
2119
2120	/* An eyecatcher for determining if we are really looking at an
2121	* association data structure.
2122	*/
2123	enum {
2124	SCTP_ASSOC_EYECATCHER = 0xa550c123,
2125	};
2126
2127	/* Recover the outter association structure. */
2128	static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2129	{
2130	struct sctp_association *asoc;
2131
2132	asoc = container_of(base, struct sctp_association, base);
2133	return asoc;
2134	}
2135
2136	/* These are function signatures for manipulating associations. */
2137
2138
2139	struct sctp_association *
2140	sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2141	enum sctp_scope scope, gfp_t gfp);
2142	void sctp_association_free(struct sctp_association *);
2143	void sctp_association_put(struct sctp_association *);
2144	void sctp_association_hold(struct sctp_association *);
2145
2146	struct sctp_transport *sctp_assoc_choose_alter_transport(
2147	struct sctp_association *, struct sctp_transport *);
2148	void sctp_assoc_update_retran_path(struct sctp_association *);
2149	struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2150	const union sctp_addr *);
2151	int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2152	const union sctp_addr *laddr);
2153	struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2154	const union sctp_addr *address,
2155	const gfp_t gfp,
2156	const int peer_state);
2157	void sctp_assoc_del_peer(struct sctp_association *asoc,
2158	const union sctp_addr *addr);
2159	void sctp_assoc_rm_peer(struct sctp_association *asoc,
2160	struct sctp_transport *peer);
2161	void sctp_assoc_control_transport(struct sctp_association *asoc,
2162	struct sctp_transport *transport,
2163	enum sctp_transport_cmd command,
2164	sctp_sn_error_t error);
2165	struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2166	void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2167	int sctp_assoc_update(struct sctp_association *old,
2168	struct sctp_association *new);
2169
2170	__u32 sctp_association_get_next_tsn(struct sctp_association *);
2171
2172	void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2173	void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2174	void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2175	void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2176	void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2177	void sctp_assoc_set_primary(struct sctp_association *,
2178	struct sctp_transport *);
2179	void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2180	struct sctp_transport *);
2181	int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2182	enum sctp_scope scope, gfp_t gfp);
2183	int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2184	struct sctp_cookie*,
2185	gfp_t gfp);
2186	int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2187	void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2188	struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2189	const struct sctp_association *asoc,
2190	__be32 serial);
2191	void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2192
2193	int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2194	const union sctp_addr *ss2);
2195	struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2196
2197	/* A convenience structure to parse out SCTP specific CMSGs. */
2198	struct sctp_cmsgs {
2199	struct sctp_initmsg *init;
2200	struct sctp_sndrcvinfo *srinfo;
2201	struct sctp_sndinfo *sinfo;
2202	struct sctp_prinfo *prinfo;
2203	struct sctp_authinfo *authinfo;
2204	struct msghdr *addrs_msg;
2205	};
2206
2207	/* Structure for tracking memory objects */
2208	struct sctp_dbg_objcnt_entry {
2209	char *label;
2210	atomic_t *counter;
2211	};
2212
2213	#endif /* __sctp_structs_h__ */
2214