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 */
  53union sctp_addr {
  54	struct sockaddr_in v4;
  55	struct sockaddr_in6 v6;
  56	struct sockaddr sa;
  57};
  58
  59/* Forward declarations for data structures. */
  60struct sctp_globals;
  61struct sctp_endpoint;
  62struct sctp_association;
  63struct sctp_transport;
  64struct sctp_packet;
  65struct sctp_chunk;
  66struct sctp_inq;
  67struct sctp_outq;
  68struct sctp_bind_addr;
  69struct sctp_ulpq;
  70struct sctp_ep_common;
  71struct crypto_shash;
  72struct 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
  82struct 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
  92struct sctp_bind_hashbucket {
  93	spinlock_t	lock;
  94	struct hlist_head	chain;
  95};
  96
  97/* Used for hashing all associations.  */
  98struct sctp_hashbucket {
  99	rwlock_t	lock;
 100	struct hlist_head	chain;
 101} __attribute__((__aligned__(8)));
 102
 103
 104/* The SCTP globals structure. */
 105extern 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. */
 142enum 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. */
 149struct 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#define sctp_sk(ptr) container_of_const(ptr, struct sctp_sock, inet.sk)
 
 
 
 246
 247static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
 248{
 249       return (struct sock *)sp;
 250}
 251
 252#if IS_ENABLED(CONFIG_IPV6)
 253struct sctp6_sock {
 254       struct sctp_sock  sctp;
 255       struct ipv6_pinfo inet6;
 256};
 257#endif /* CONFIG_IPV6 */
 258
 259
 260/* This is our APPLICATION-SPECIFIC state cookie.
 261 * THIS IS NOT DICTATED BY THE SPECIFICATION.
 262 */
 263/* These are the parts of an association which we send in the cookie.
 264 * Most of these are straight out of:
 265 * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
 266 *
 267 */
 268
 269struct sctp_cookie {
 270
 271	/* My	       : Tag expected in every inbound packet and sent
 272	 * Verification: in the INIT or INIT ACK chunk.
 273	 * Tag	       :
 274	 */
 275	__u32 my_vtag;
 276
 277	/* Peer's      : Tag expected in every outbound packet except
 278	 * Verification: in the INIT chunk.
 279	 * Tag	       :
 280	 */
 281	__u32 peer_vtag;
 282
 283	/* The rest of these are not from the spec, but really need to
 284	 * be in the cookie.
 285	 */
 286
 287	/* My Tie Tag  : Assist in discovering a restarting association. */
 288	__u32 my_ttag;
 289
 290	/* Peer's Tie Tag: Assist in discovering a restarting association. */
 291	__u32 peer_ttag;
 292
 293	/* When does this cookie expire? */
 294	ktime_t expiration;
 295
 296	/* Number of inbound/outbound streams which are set
 297	 * and negotiated during the INIT process.
 298	 */
 299	__u16 sinit_num_ostreams;
 300	__u16 sinit_max_instreams;
 301
 302	/* This is the first sequence number I used.  */
 303	__u32 initial_tsn;
 304
 305	/* This holds the originating address of the INIT packet.  */
 306	union sctp_addr peer_addr;
 307
 308	/* IG Section 2.35.3 
 309	 * Include the source port of the INIT-ACK
 310	 */
 311	__u16		my_port;
 312
 313	__u8 prsctp_capable;
 314
 315	/* Padding for future use */
 316	__u8 padding;  		
 317
 318	__u32 adaptation_ind;
 319
 320	__u8 auth_random[sizeof(struct sctp_paramhdr) +
 321			 SCTP_AUTH_RANDOM_LENGTH];
 322	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
 323	__u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
 324
 325	/* This is a shim for my peer's INIT packet, followed by
 326	 * a copy of the raw address list of the association.
 327	 * The length of the raw address list is saved in the
 328	 * raw_addr_list_len field, which will be used at the time when
 329	 * the association TCB is re-constructed from the cookie.
 330	 */
 331	__u32 raw_addr_list_len;
 332	/* struct sctp_init_chunk peer_init[]; */
 333};
 334
 335
 336/* The format of our cookie that we send to our peer. */
 337struct sctp_signed_cookie {
 338	__u8 signature[SCTP_SECRET_SIZE];
 339	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
 340	struct sctp_cookie c;
 341} __packed;
 342
 343/* This is another convenience type to allocate memory for address
 344 * params for the maximum size and pass such structures around
 345 * internally.
 346 */
 347union sctp_addr_param {
 348	struct sctp_paramhdr p;
 349	struct sctp_ipv4addr_param v4;
 350	struct sctp_ipv6addr_param v6;
 351};
 352
 353/* A convenience type to allow walking through the various
 354 * parameters and avoid casting all over the place.
 355 */
 356union sctp_params {
 357	void *v;
 358	struct sctp_paramhdr *p;
 359	struct sctp_cookie_preserve_param *life;
 360	struct sctp_hostname_param *dns;
 361	struct sctp_cookie_param *cookie;
 362	struct sctp_supported_addrs_param *sat;
 363	struct sctp_ipv4addr_param *v4;
 364	struct sctp_ipv6addr_param *v6;
 365	union sctp_addr_param *addr;
 366	struct sctp_adaptation_ind_param *aind;
 367	struct sctp_supported_ext_param *ext;
 368	struct sctp_random_param *random;
 369	struct sctp_chunks_param *chunks;
 370	struct sctp_hmac_algo_param *hmac_algo;
 371	struct sctp_addip_param *addip;
 372};
 373
 374/* RFC 2960.  Section 3.3.5 Heartbeat.
 375 *    Heartbeat Information: variable length
 376 *    The Sender-specific Heartbeat Info field should normally include
 377 *    information about the sender's current time when this HEARTBEAT
 378 *    chunk is sent and the destination transport address to which this
 379 *    HEARTBEAT is sent (see Section 8.3).
 380 */
 381struct sctp_sender_hb_info {
 382	struct sctp_paramhdr param_hdr;
 383	union sctp_addr daddr;
 384	unsigned long sent_at;
 385	__u64 hb_nonce;
 386	__u32 probe_size;
 387};
 388
 389int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
 390		     gfp_t gfp);
 391int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
 392void sctp_stream_free(struct sctp_stream *stream);
 393void sctp_stream_clear(struct sctp_stream *stream);
 394void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
 395
 396/* What is the current SSN number for this stream? */
 397#define sctp_ssn_peek(stream, type, sid) \
 398	(sctp_stream_##type((stream), (sid))->ssn)
 399
 400/* Return the next SSN number for this stream.	*/
 401#define sctp_ssn_next(stream, type, sid) \
 402	(sctp_stream_##type((stream), (sid))->ssn++)
 403
 404/* Skip over this ssn and all below. */
 405#define sctp_ssn_skip(stream, type, sid, ssn) \
 406	(sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
 407
 408/* What is the current MID number for this stream? */
 409#define sctp_mid_peek(stream, type, sid) \
 410	(sctp_stream_##type((stream), (sid))->mid)
 411
 412/* Return the next MID number for this stream.  */
 413#define sctp_mid_next(stream, type, sid) \
 414	(sctp_stream_##type((stream), (sid))->mid++)
 415
 416/* Skip over this mid and all below. */
 417#define sctp_mid_skip(stream, type, sid, mid) \
 418	(sctp_stream_##type((stream), (sid))->mid = mid + 1)
 419
 420/* What is the current MID_uo number for this stream? */
 421#define sctp_mid_uo_peek(stream, type, sid) \
 422	(sctp_stream_##type((stream), (sid))->mid_uo)
 423
 424/* Return the next MID_uo number for this stream.  */
 425#define sctp_mid_uo_next(stream, type, sid) \
 426	(sctp_stream_##type((stream), (sid))->mid_uo++)
 427
 428/*
 429 * Pointers to address related SCTP functions.
 430 * (i.e. things that depend on the address family.)
 431 */
 432struct sctp_af {
 433	int		(*sctp_xmit)	(struct sk_buff *skb,
 434					 struct sctp_transport *);
 435	int		(*setsockopt)	(struct sock *sk,
 436					 int level,
 437					 int optname,
 438					 sockptr_t optval,
 439					 unsigned int optlen);
 440	int		(*getsockopt)	(struct sock *sk,
 441					 int level,
 442					 int optname,
 443					 char __user *optval,
 444					 int __user *optlen);
 445	void		(*get_dst)	(struct sctp_transport *t,
 446					 union sctp_addr *saddr,
 447					 struct flowi *fl,
 448					 struct sock *sk);
 449	void		(*get_saddr)	(struct sctp_sock *sk,
 450					 struct sctp_transport *t,
 451					 struct flowi *fl);
 452	void		(*copy_addrlist) (struct list_head *,
 453					  struct net_device *);
 454	int		(*cmp_addr)	(const union sctp_addr *addr1,
 455					 const union sctp_addr *addr2);
 456	void		(*addr_copy)	(union sctp_addr *dst,
 457					 union sctp_addr *src);
 458	void		(*from_skb)	(union sctp_addr *,
 459					 struct sk_buff *skb,
 460					 int saddr);
 461	void		(*from_sk)	(union sctp_addr *,
 462					 struct sock *sk);
 463	bool		(*from_addr_param) (union sctp_addr *,
 464					    union sctp_addr_param *,
 465					    __be16 port, int iif);
 466	int		(*to_addr_param) (const union sctp_addr *,
 467					  union sctp_addr_param *); 
 468	int		(*addr_valid)	(union sctp_addr *,
 469					 struct sctp_sock *,
 470					 const struct sk_buff *);
 471	enum sctp_scope	(*scope)(union sctp_addr *);
 472	void		(*inaddr_any)	(union sctp_addr *, __be16);
 473	int		(*is_any)	(const union sctp_addr *);
 474	int		(*available)	(union sctp_addr *,
 475					 struct sctp_sock *);
 476	int		(*skb_iif)	(const struct sk_buff *sk);
 477	int		(*skb_sdif)(const struct sk_buff *sk);
 478	int		(*is_ce)	(const struct sk_buff *sk);
 479	void		(*seq_dump_addr)(struct seq_file *seq,
 480					 union sctp_addr *addr);
 481	void		(*ecn_capable)(struct sock *sk);
 482	__u16		net_header_len;
 483	int		sockaddr_len;
 484	int		(*ip_options_len)(struct sock *sk);
 485	sa_family_t	sa_family;
 486	struct list_head list;
 487};
 488
 489struct sctp_af *sctp_get_af_specific(sa_family_t);
 490int sctp_register_af(struct sctp_af *);
 491
 492/* Protocol family functions. */
 493struct sctp_pf {
 494	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
 495	void (*skb_msgname)  (struct sk_buff *, char *, int *);
 496	int  (*af_supported) (sa_family_t, struct sctp_sock *);
 497	int  (*cmp_addr) (const union sctp_addr *,
 498			  const union sctp_addr *,
 499			  struct sctp_sock *);
 500	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
 501	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
 502	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
 503	struct sock *(*create_accept_sk) (struct sock *sk,
 504					  struct sctp_association *asoc,
 505					  bool kern);
 506	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
 507	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
 508	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
 509	void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
 510	struct sctp_af *af;
 511};
 512
 513
 514/* Structure to track chunk fragments that have been acked, but peer
 515 * fragments of the same message have not.
 516 */
 517struct sctp_datamsg {
 518	/* Chunks waiting to be submitted to lower layer. */
 519	struct list_head chunks;
 520	/* Reference counting. */
 521	refcount_t refcnt;
 522	/* When is this message no longer interesting to the peer? */
 523	unsigned long expires_at;
 524	/* Did the message fail to send? */
 525	int send_error;
 526	u8 send_failed:1,
 527	   can_delay:1,	/* should this message be Nagle delayed */
 528	   abandoned:1;	/* should this message be abandoned */
 529};
 530
 531struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
 532					    struct sctp_sndrcvinfo *,
 533					    struct iov_iter *);
 534void sctp_datamsg_free(struct sctp_datamsg *);
 535void sctp_datamsg_put(struct sctp_datamsg *);
 536void sctp_chunk_fail(struct sctp_chunk *, int error);
 537int sctp_chunk_abandoned(struct sctp_chunk *);
 538
 539/* RFC2960 1.4 Key Terms
 540 *
 541 * o Chunk: A unit of information within an SCTP packet, consisting of
 542 * a chunk header and chunk-specific content.
 543 *
 544 * As a matter of convenience, we remember the SCTP common header for
 545 * each chunk as well as a few other header pointers...
 546 */
 547struct sctp_chunk {
 548	struct list_head list;
 549
 550	refcount_t refcnt;
 551
 552	/* How many times this chunk have been sent, for prsctp RTX policy */
 553	int sent_count;
 554
 555	union {
 556		/* This is our link to the per-transport transmitted list.  */
 557		struct list_head transmitted_list;
 558		/* List in specific stream outq */
 559		struct list_head stream_list;
 560	};
 561
 562	/* This field is used by chunks that hold fragmented data.
 563	 * For the first fragment this is the list that holds the rest of
 564	 * fragments. For the remaining fragments, this is the link to the
 565	 * frag_list maintained in the first fragment.
 566	 */
 567	struct list_head frag_list;
 568
 569	/* This points to the sk_buff containing the actual data.  */
 570	struct sk_buff *skb;
 571
 572	union {
 573		/* In case of GSO packets, this will store the head one */
 574		struct sk_buff *head_skb;
 575		/* In case of auth enabled, this will point to the shkey */
 576		struct sctp_shared_key *shkey;
 577	};
 578
 579	/* These are the SCTP headers by reverse order in a packet.
 580	 * Note that some of these may happen more than once.  In that
 581	 * case, we point at the "current" one, whatever that means
 582	 * for that level of header.
 583	 */
 584
 585	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
 586	union sctp_params param_hdr;
 587	union {
 588		__u8 *v;
 589		struct sctp_datahdr *data_hdr;
 590		struct sctp_inithdr *init_hdr;
 591		struct sctp_sackhdr *sack_hdr;
 592		struct sctp_heartbeathdr *hb_hdr;
 593		struct sctp_sender_hb_info *hbs_hdr;
 594		struct sctp_shutdownhdr *shutdown_hdr;
 595		struct sctp_signed_cookie *cookie_hdr;
 596		struct sctp_ecnehdr *ecne_hdr;
 597		struct sctp_cwrhdr *ecn_cwr_hdr;
 598		struct sctp_errhdr *err_hdr;
 599		struct sctp_addiphdr *addip_hdr;
 600		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
 601		struct sctp_authhdr *auth_hdr;
 602		struct sctp_idatahdr *idata_hdr;
 603		struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
 604	} subh;
 605
 606	__u8 *chunk_end;
 607
 608	struct sctp_chunkhdr *chunk_hdr;
 609	struct sctphdr *sctp_hdr;
 610
 611	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
 612	struct sctp_sndrcvinfo sinfo;
 613
 614	/* Which association does this belong to?  */
 615	struct sctp_association *asoc;
 616
 617	/* What endpoint received this chunk? */
 618	struct sctp_ep_common *rcvr;
 619
 620	/* We fill this in if we are calculating RTT. */
 621	unsigned long sent_at;
 622
 623	/* What is the origin IP address for this chunk?  */
 624	union sctp_addr source;
 625	/* Destination address for this chunk. */
 626	union sctp_addr dest;
 627
 628	/* For outbound message, track all fragments for SEND_FAILED. */
 629	struct sctp_datamsg *msg;
 630
 631	/* For an inbound chunk, this tells us where it came from.
 632	 * For an outbound chunk, it tells us where we'd like it to
 633	 * go.	It is NULL if we have no preference.
 634	 */
 635	struct sctp_transport *transport;
 636
 637	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
 638	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
 639	 * spec violates the principle premis that all chunks are processed
 640	 * in order.
 641	 */
 642	struct sk_buff *auth_chunk;
 643
 644#define SCTP_CAN_FRTX 0x0
 645#define SCTP_NEED_FRTX 0x1
 646#define SCTP_DONT_FRTX 0x2
 647	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
 648		has_tsn:1,		/* Does this chunk have a TSN yet? */
 649		has_ssn:1,		/* Does this chunk have a SSN yet? */
 650#define has_mid has_ssn
 651		singleton:1,		/* Only chunk in the packet? */
 652		end_of_packet:1,	/* Last chunk in the packet? */
 653		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
 654		pdiscard:1,		/* Discard the whole packet now? */
 655		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
 656		data_accepted:1,	/* At least 1 chunk accepted */
 657		auth:1,			/* IN: was auth'ed | OUT: needs auth */
 658		has_asconf:1,		/* IN: have seen an asconf before */
 659		pmtu_probe:1,		/* Used by PLPMTUD, can be set in s HB chunk */
 660		tsn_missing_report:2,	/* Data chunk missing counter. */
 661		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
 662};
 663
 664#define sctp_chunk_retransmitted(chunk)	(chunk->sent_count > 1)
 665void sctp_chunk_hold(struct sctp_chunk *);
 666void sctp_chunk_put(struct sctp_chunk *);
 667int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
 668			  struct iov_iter *from);
 669void sctp_chunk_free(struct sctp_chunk *);
 670void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
 671struct sctp_chunk *sctp_chunkify(struct sk_buff *,
 672				 const struct sctp_association *,
 673				 struct sock *, gfp_t gfp);
 674void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
 675		     union sctp_addr *);
 676const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
 677
 678static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
 679{
 680	return ntohs(ch->subh.data_hdr->stream);
 681}
 682
 683enum {
 684	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
 685	SCTP_ADDR_SRC,		/* address can be used as source */
 686	SCTP_ADDR_DEL,		/* address about to be deleted */
 687};
 688
 689/* This is a structure for holding either an IPv6 or an IPv4 address.  */
 690struct sctp_sockaddr_entry {
 691	struct list_head list;
 692	struct rcu_head	rcu;
 693	union sctp_addr a;
 694	__u8 state;
 695	__u8 valid;
 696};
 697
 698#define SCTP_ADDRESS_TICK_DELAY	500
 699
 700/* This structure holds lists of chunks as we are assembling for
 701 * transmission.
 702 */
 703struct sctp_packet {
 704	/* These are the SCTP header values (host order) for the packet. */
 705	__u16 source_port;
 706	__u16 destination_port;
 707	__u32 vtag;
 708
 709	/* This contains the payload chunks.  */
 710	struct list_head chunk_list;
 711
 712	/* This is the overhead of the sctp and ip headers. */
 713	size_t overhead;
 714	/* This is the total size of all chunks INCLUDING padding.  */
 715	size_t size;
 716	/* This is the maximum size this packet may have */
 717	size_t max_size;
 718
 719	/* The packet is destined for this transport address.
 720	 * The function we finally use to pass down to the next lower
 721	 * layer lives in the transport structure.
 722	 */
 723	struct sctp_transport *transport;
 724
 725	/* pointer to the auth chunk for this packet */
 726	struct sctp_chunk *auth;
 727
 728	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
 729	    has_sack:1,		/* This packet contains a SACK chunk. */
 730	    has_auth:1,		/* This packet contains an AUTH chunk */
 731	    has_data:1,		/* This packet contains at least 1 DATA chunk */
 732	    ipfragok:1;		/* So let ip fragment this packet */
 733};
 734
 735void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
 736		      __u16 sport, __u16 dport);
 737void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
 738enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
 739					  struct sctp_chunk *chunk,
 740					  int one_packet, gfp_t gfp);
 741enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
 742					struct sctp_chunk *chunk);
 743int sctp_packet_transmit(struct sctp_packet *, gfp_t);
 744void sctp_packet_free(struct sctp_packet *);
 745
 746static inline int sctp_packet_empty(struct sctp_packet *packet)
 747{
 748	return packet->size == packet->overhead;
 749}
 750
 751/* This represents a remote transport address.
 752 * For local transport addresses, we just use union sctp_addr.
 753 *
 754 * RFC2960 Section 1.4 Key Terms
 755 *
 756 *   o	Transport address:  A Transport Address is traditionally defined
 757 *	by Network Layer address, Transport Layer protocol and Transport
 758 *	Layer port number.  In the case of SCTP running over IP, a
 759 *	transport address is defined by the combination of an IP address
 760 *	and an SCTP port number (where SCTP is the Transport protocol).
 761 *
 762 * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
 763 *
 764 *   o	The sender keeps a separate congestion control parameter set for
 765 *	each of the destination addresses it can send to (not each
 766 *	source-destination pair but for each destination).  The parameters
 767 *	should decay if the address is not used for a long enough time
 768 *	period.
 769 *
 770 */
 771struct sctp_transport {
 772	/* A list of transports. */
 773	struct list_head transports;
 774	struct rhlist_head node;
 775
 776	/* Reference counting. */
 777	refcount_t refcnt;
 778		/* RTO-Pending : A flag used to track if one of the DATA
 779		 *		chunks sent to this address is currently being
 780		 *		used to compute a RTT. If this flag is 0,
 781		 *		the next DATA chunk sent to this destination
 782		 *		should be used to compute a RTT and this flag
 783		 *		should be set. Every time the RTT
 784		 *		calculation completes (i.e. the DATA chunk
 785		 *		is SACK'd) clear this flag.
 786		 */
 787	__u32	rto_pending:1,
 788
 789		/*
 790		 * hb_sent : a flag that signals that we have a pending
 791		 * heartbeat.
 792		 */
 793		hb_sent:1,
 794
 795		/* Is the Path MTU update pending on this transport */
 796		pmtu_pending:1,
 797
 798		dst_pending_confirm:1,	/* need to confirm neighbour */
 799
 800		/* Has this transport moved the ctsn since we last sacked */
 801		sack_generation:1;
 802	u32 dst_cookie;
 803
 804	struct flowi fl;
 805
 806	/* This is the peer's IP address and port. */
 807	union sctp_addr ipaddr;
 808
 809	/* These are the functions we call to handle LLP stuff.	 */
 810	struct sctp_af *af_specific;
 811
 812	/* Which association do we belong to?  */
 813	struct sctp_association *asoc;
 814
 815	/* RFC2960
 816	 *
 817	 * 12.3 Per Transport Address Data
 818	 *
 819	 * For each destination transport address in the peer's
 820	 * address list derived from the INIT or INIT ACK chunk, a
 821	 * number of data elements needs to be maintained including:
 822	 */
 823	/* RTO	       : The current retransmission timeout value.  */
 824	unsigned long rto;
 825
 826	__u32 rtt;		/* This is the most recent RTT.	 */
 827
 828	/* RTTVAR      : The current RTT variation.  */
 829	__u32 rttvar;
 830
 831	/* SRTT	       : The current smoothed round trip time.	*/
 832	__u32 srtt;
 833
 834	/*
 835	 * These are the congestion stats.
 836	 */
 837	/* cwnd	       : The current congestion window.	 */
 838	__u32 cwnd;		  /* This is the actual cwnd.  */
 839
 840	/* ssthresh    : The current slow start threshold value.  */
 841	__u32 ssthresh;
 842
 843	/* partial     : The tracking method for increase of cwnd when in
 844	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
 845	 */
 846	__u32 partial_bytes_acked;
 847
 848	/* Data that has been sent, but not acknowledged. */
 849	__u32 flight_size;
 850
 851	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
 852
 853	/* Destination */
 854	struct dst_entry *dst;
 855	/* Source address. */
 856	union sctp_addr saddr;
 857
 858	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
 859	 * the destination address every heartbeat interval.
 860	 */
 861	unsigned long hbinterval;
 862	unsigned long probe_interval;
 863
 864	/* SACK delay timeout */
 865	unsigned long sackdelay;
 866	__u32 sackfreq;
 867
 868	atomic_t mtu_info;
 869
 870	/* When was the last time that we heard from this transport? We use
 871	 * this to pick new active and retran paths.
 872	 */
 873	ktime_t last_time_heard;
 874
 875	/* When was the last time that we sent a chunk using this
 876	 * transport? We use this to check for idle transports
 877	 */
 878	unsigned long last_time_sent;
 879
 880	/* Last time(in jiffies) when cwnd is reduced due to the congestion
 881	 * indication based on ECNE chunk.
 882	 */
 883	unsigned long last_time_ecne_reduced;
 884
 885	__be16 encap_port;
 886
 887	/* This is the max_retrans value for the transport and will
 888	 * be initialized from the assocs value.  This can be changed
 889	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
 890	 */
 891	__u16 pathmaxrxt;
 892
 893	__u32 flowlabel;
 894	__u8  dscp;
 895
 896	/* This is the partially failed retrans value for the transport
 897	 * and will be initialized from the assocs value.  This can be changed
 898	 * using the SCTP_PEER_ADDR_THLDS socket option
 899	 */
 900	__u16 pf_retrans;
 901	/* Used for primary path switchover. */
 902	__u16 ps_retrans;
 903	/* PMTU	      : The current known path MTU.  */
 904	__u32 pathmtu;
 905
 906	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
 907	__u32 param_flags;
 908
 909	/* The number of times INIT has been sent on this transport. */
 910	int init_sent_count;
 911
 912	/* state       : The current state of this destination,
 913	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
 914	 */
 915	int state;
 916
 917	/* These are the error stats for this destination.  */
 918
 919	/* Error count : The current error count for this destination.	*/
 920	unsigned short error_count;
 921
 922	/* Per	       : A timer used by each destination.
 923	 * Destination :
 924	 * Timer       :
 925	 *
 926	 * [Everywhere else in the text this is called T3-rtx. -ed]
 927	 */
 928	struct timer_list T3_rtx_timer;
 929
 930	/* Heartbeat timer is per destination. */
 931	struct timer_list hb_timer;
 932
 933	/* Timer to handle ICMP proto unreachable envets */
 934	struct timer_list proto_unreach_timer;
 935
 936	/* Timer to handler reconf chunk rtx */
 937	struct timer_list reconf_timer;
 938
 939	/* Timer to send a probe HB packet for PLPMTUD */
 940	struct timer_list probe_timer;
 941
 942	/* Since we're using per-destination retransmission timers
 943	 * (see above), we're also using per-destination "transmitted"
 944	 * queues.  This probably ought to be a private struct
 945	 * accessible only within the outqueue, but it's not, yet.
 946	 */
 947	struct list_head transmitted;
 948
 949	/* We build bundle-able packets for this transport here.  */
 950	struct sctp_packet packet;
 951
 952	/* This is the list of transports that have chunks to send.  */
 953	struct list_head send_ready;
 954
 955	/* State information saved for SFR_CACC algorithm. The key
 956	 * idea in SFR_CACC is to maintain state at the sender on a
 957	 * per-destination basis when a changeover happens.
 958	 *	char changeover_active;
 959	 *	char cycling_changeover;
 960	 *	__u32 next_tsn_at_change;
 961	 *	char cacc_saw_newack;
 962	 */
 963	struct {
 964		/* An unsigned integer, which stores the next TSN to be
 965		 * used by the sender, at the moment of changeover.
 966		 */
 967		__u32 next_tsn_at_change;
 968
 969		/* A flag which indicates the occurrence of a changeover */
 970		char changeover_active;
 971
 972		/* A flag which indicates whether the change of primary is
 973		 * the first switch to this destination address during an
 974		 * active switch.
 975		 */
 976		char cycling_changeover;
 977
 978		/* A temporary flag, which is used during the processing of
 979		 * a SACK to estimate the causative TSN(s)'s group.
 980		 */
 981		char cacc_saw_newack;
 982	} cacc;
 983
 984	struct {
 985		__u16 pmtu;
 986		__u16 probe_size;
 987		__u16 probe_high;
 988		__u8 probe_count;
 989		__u8 state;
 990	} pl; /* plpmtud related */
 991
 992	/* 64-bit random number sent with heartbeat. */
 993	__u64 hb_nonce;
 994
 995	struct rcu_head rcu;
 996};
 997
 998struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
 999					  gfp_t);
1000void sctp_transport_set_owner(struct sctp_transport *,
1001			      struct sctp_association *);
1002void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1003			  struct sctp_sock *);
1004void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
1005void sctp_transport_free(struct sctp_transport *);
1006void sctp_transport_reset_t3_rtx(struct sctp_transport *);
1007void sctp_transport_reset_hb_timer(struct sctp_transport *);
1008void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
1009void sctp_transport_reset_probe_timer(struct sctp_transport *transport);
1010void sctp_transport_reset_raise_timer(struct sctp_transport *transport);
1011int sctp_transport_hold(struct sctp_transport *);
1012void sctp_transport_put(struct sctp_transport *);
1013void sctp_transport_update_rto(struct sctp_transport *, __u32);
1014void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1015void sctp_transport_lower_cwnd(struct sctp_transport *t,
1016			       enum sctp_lower_cwnd reason);
1017void sctp_transport_burst_limited(struct sctp_transport *);
1018void sctp_transport_burst_reset(struct sctp_transport *);
1019unsigned long sctp_transport_timeout(struct sctp_transport *);
1020void sctp_transport_reset(struct sctp_transport *t);
1021bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1022void sctp_transport_immediate_rtx(struct sctp_transport *);
1023void sctp_transport_dst_release(struct sctp_transport *t);
1024void sctp_transport_dst_confirm(struct sctp_transport *t);
1025void sctp_transport_pl_send(struct sctp_transport *t);
1026bool sctp_transport_pl_recv(struct sctp_transport *t);
1027
1028
1029/* This is the structure we use to queue packets as they come into
1030 * SCTP.  We write packets to it and read chunks from it.
1031 */
1032struct sctp_inq {
1033	/* This is actually a queue of sctp_chunk each
1034	 * containing a partially decoded packet.
1035	 */
1036	struct list_head in_chunk_list;
1037	/* This is the packet which is currently off the in queue and is
1038	 * being worked on through the inbound chunk processing.
1039	 */
1040	struct sctp_chunk *in_progress;
1041
1042	/* This is the delayed task to finish delivering inbound
1043	 * messages.
1044	 */
1045	struct work_struct immediate;
1046};
1047
1048void sctp_inq_init(struct sctp_inq *);
1049void sctp_inq_free(struct sctp_inq *);
1050void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1051struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1052struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1053void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1054
1055/* This is the structure we use to hold outbound chunks.  You push
1056 * chunks in and they automatically pop out the other end as bundled
1057 * packets (it calls (*output_handler)()).
1058 *
1059 * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1060 * and 8.2 of the v13 draft.
1061 *
1062 * It handles retransmissions.	The connection to the timeout portion
1063 * of the state machine is through sctp_..._timeout() and timeout_handler.
1064 *
1065 * If you feed it SACKs, it will eat them.
1066 *
1067 * If you give it big chunks, it will fragment them.
1068 *
1069 * It assigns TSN's to data chunks.  This happens at the last possible
1070 * instant before transmission.
1071 *
1072 * When free()'d, it empties itself out via output_handler().
1073 */
1074struct sctp_outq {
1075	struct sctp_association *asoc;
1076
1077	/* Data pending that has never been transmitted.  */
1078	struct list_head out_chunk_list;
1079
1080	/* Stream scheduler being used */
1081	struct sctp_sched_ops *sched;
1082
1083	unsigned int out_qlen;	/* Total length of queued data chunks. */
1084
1085	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1086	unsigned int error;
1087
1088	/* These are control chunks we want to send.  */
1089	struct list_head control_chunk_list;
1090
1091	/* These are chunks that have been sacked but are above the
1092	 * CTSN, or cumulative tsn ack point.
1093	 */
1094	struct list_head sacked;
1095
1096	/* Put chunks on this list to schedule them for
1097	 * retransmission.
1098	 */
1099	struct list_head retransmit;
1100
1101	/* Put chunks on this list to save them for FWD TSN processing as
1102	 * they were abandoned.
1103	 */
1104	struct list_head abandoned;
1105
1106	/* How many unackd bytes do we have in-flight?	*/
1107	__u32 outstanding_bytes;
1108
1109	/* Are we doing fast-rtx on this queue */
1110	char fast_rtx;
1111
1112	/* Corked? */
1113	char cork;
1114};
1115
1116void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1117void sctp_outq_teardown(struct sctp_outq *);
1118void sctp_outq_free(struct sctp_outq*);
1119void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1120int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1121int sctp_outq_is_empty(const struct sctp_outq *);
1122void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1123		     enum sctp_retransmit_reason reason);
1124void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1125void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1126void sctp_prsctp_prune(struct sctp_association *asoc,
1127		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1128void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1129/* Uncork and flush an outqueue.  */
1130static inline void sctp_outq_cork(struct sctp_outq *q)
1131{
1132	q->cork = 1;
1133}
1134
1135/* SCTP skb control block.
1136 * sctp_input_cb is currently used on rx and sock rx queue
1137 */
1138struct sctp_input_cb {
1139	union {
1140		struct inet_skb_parm    h4;
1141#if IS_ENABLED(CONFIG_IPV6)
1142		struct inet6_skb_parm   h6;
1143#endif
1144	} header;
1145	struct sctp_chunk *chunk;
1146	struct sctp_af *af;
1147	__be16 encap_port;
1148};
1149#define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1150
1151struct sctp_output_cb {
1152	struct sk_buff *last;
1153};
1154#define SCTP_OUTPUT_CB(__skb)	((struct sctp_output_cb *)&((__skb)->cb[0]))
1155
1156static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1157{
1158	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1159
1160	return chunk->head_skb ? : skb;
1161}
1162
1163/* These bind address data fields common between endpoints and associations */
1164struct sctp_bind_addr {
1165
1166	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1167	 *
1168	 * SCTP Port:	The local SCTP port number the endpoint is
1169	 *		bound to.
1170	 */
1171	__u16 port;
1172
1173	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1174	 *
1175	 * Address List: The list of IP addresses that this instance
1176	 *	has bound.  This information is passed to one's
1177	 *	peer(s) in INIT and INIT ACK chunks.
1178	 */
1179	struct list_head address_list;
1180};
1181
1182void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1183void sctp_bind_addr_free(struct sctp_bind_addr *);
1184int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1185			const struct sctp_bind_addr *src,
1186			enum sctp_scope scope, gfp_t gfp,
1187			int flags);
1188int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1189			const struct sctp_bind_addr *src,
1190			gfp_t gfp);
1191int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1192		       int new_size, __u8 addr_state, gfp_t gfp);
1193int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1194int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1195			 struct sctp_sock *);
1196int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1197			 struct sctp_sock *, struct sctp_sock *);
1198int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1199			 const union sctp_addr *addr);
1200int sctp_bind_addrs_check(struct sctp_sock *sp,
1201			  struct sctp_sock *sp2, int cnt2);
1202union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1203					const union sctp_addr	*addrs,
1204					int			addrcnt,
1205					struct sctp_sock	*opt);
1206union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1207					 int *addrs_len,
1208					 gfp_t gfp);
1209int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1210			   __u16 port, gfp_t gfp);
1211
1212enum sctp_scope sctp_scope(const union sctp_addr *addr);
1213int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1214		  const enum sctp_scope scope);
1215int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1216int sctp_is_ep_boundall(struct sock *sk);
1217
1218
1219/* What type of endpoint?  */
1220enum sctp_endpoint_type {
1221	SCTP_EP_TYPE_SOCKET,
1222	SCTP_EP_TYPE_ASSOCIATION,
1223};
1224
1225/*
1226 * A common base class to bridge the implementation view of a
1227 * socket (usually listening) endpoint versus an association's
1228 * local endpoint.
1229 * This common structure is useful for several purposes:
1230 *   1) Common interface for lookup routines.
1231 *	a) Subfunctions work for either endpoint or association
1232 *	b) Single interface to lookup allows hiding the lookup lock rather
1233 *	   than acquiring it externally.
1234 *   2) Common interface for the inbound chunk handling/state machine.
1235 *   3) Common object handling routines for reference counting, etc.
1236 *   4) Disentangle association lookup from endpoint lookup, where we
1237 *	do not have to find our endpoint to find our association.
1238 *
1239 */
1240
1241struct sctp_ep_common {
1242	/* Runtime type information.  What kind of endpoint is this? */
1243	enum sctp_endpoint_type type;
1244
1245	/* Some fields to help us manage this object.
1246	 *   refcnt   - Reference count access to this object.
1247	 *   dead     - Do not attempt to use this object.
1248	 */
1249	refcount_t    refcnt;
1250	bool	    dead;
1251
1252	/* What socket does this endpoint belong to?  */
1253	struct sock *sk;
1254
1255	/* Cache netns and it won't change once set */
1256	struct net *net;
1257
1258	/* This is where we receive inbound chunks.  */
1259	struct sctp_inq	  inqueue;
1260
1261	/* This substructure includes the defining parameters of the
1262	 * endpoint:
1263	 * bind_addr.port is our shared port number.
1264	 * bind_addr.address_list is our set of local IP addresses.
1265	 */
1266	struct sctp_bind_addr bind_addr;
1267};
1268
1269
1270/* RFC Section 1.4 Key Terms
1271 *
1272 * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1273 *   multi-homed host, an SCTP endpoint is represented to its peers as a
1274 *   combination of a set of eligible destination transport addresses to
1275 *   which SCTP packets can be sent and a set of eligible source
1276 *   transport addresses from which SCTP packets can be received.
1277 *   All transport addresses used by an SCTP endpoint must use the
1278 *   same port number, but can use multiple IP addresses. A transport
1279 *   address used by an SCTP endpoint must not be used by another
1280 *   SCTP endpoint. In other words, a transport address is unique
1281 *   to an SCTP endpoint.
1282 *
1283 * From an implementation perspective, each socket has one of these.
1284 * A TCP-style socket will have exactly one association on one of
1285 * these.  An UDP-style socket will have multiple associations hanging
1286 * off one of these.
1287 */
1288
1289struct sctp_endpoint {
1290	/* Common substructure for endpoint and association. */
1291	struct sctp_ep_common base;
1292
1293	/* Fields to help us manage our entries in the hash tables. */
1294	struct hlist_node node;
1295	int hashent;
1296
1297	/* Associations: A list of current associations and mappings
1298	 *	      to the data consumers for each association. This
1299	 *	      may be in the form of a hash table or other
1300	 *	      implementation dependent structure. The data
1301	 *	      consumers may be process identification
1302	 *	      information such as file descriptors, named pipe
1303	 *	      pointer, or table pointers dependent on how SCTP
1304	 *	      is implemented.
1305	 */
1306	/* This is really a list of struct sctp_association entries. */
1307	struct list_head asocs;
1308
1309	/* Secret Key: A secret key used by this endpoint to compute
1310	 *	      the MAC.	This SHOULD be a cryptographic quality
1311	 *	      random number with a sufficient length.
1312	 *	      Discussion in [RFC1750] can be helpful in
1313	 *	      selection of the key.
1314	 */
1315	__u8 secret_key[SCTP_SECRET_SIZE];
1316
1317 	/* digest:  This is a digest of the sctp cookie.  This field is
1318 	 * 	    only used on the receive path when we try to validate
1319 	 * 	    that the cookie has not been tampered with.  We put
1320 	 * 	    this here so we pre-allocate this once and can re-use
1321 	 * 	    on every receive.
1322 	 */
1323 	__u8 *digest;
1324 
1325	/* sendbuf acct. policy.	*/
1326	__u32 sndbuf_policy;
1327
1328	/* rcvbuf acct. policy.	*/
1329	__u32 rcvbuf_policy;
1330
1331	/* SCTP AUTH: array of the HMACs that will be allocated
1332	 * we need this per association so that we don't serialize
1333	 */
1334	struct crypto_shash **auth_hmacs;
1335
1336	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1337	 struct sctp_hmac_algo_param *auth_hmacs_list;
1338
1339	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1340	struct sctp_chunks_param *auth_chunk_list;
1341
1342	/* SCTP-AUTH: endpoint shared keys */
1343	struct list_head endpoint_shared_keys;
1344	__u16 active_key_id;
1345	__u8  ecn_enable:1,
1346	      auth_enable:1,
1347	      intl_enable:1,
1348	      prsctp_enable:1,
1349	      asconf_enable:1,
1350	      reconf_enable:1;
1351
1352	__u8  strreset_enable;
1353	struct rcu_head rcu;
1354};
1355
1356/* Recover the outer endpoint structure. */
1357static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1358{
1359	struct sctp_endpoint *ep;
1360
1361	ep = container_of(base, struct sctp_endpoint, base);
1362	return ep;
1363}
1364
1365/* These are function signatures for manipulating endpoints.  */
1366struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1367void sctp_endpoint_free(struct sctp_endpoint *);
1368void sctp_endpoint_put(struct sctp_endpoint *);
1369int sctp_endpoint_hold(struct sctp_endpoint *ep);
1370void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1371struct sctp_association *sctp_endpoint_lookup_assoc(
1372	const struct sctp_endpoint *ep,
1373	const union sctp_addr *paddr,
1374	struct sctp_transport **);
1375bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1376				 const union sctp_addr *paddr);
1377struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
1378					     struct net *net,
1379					     const union sctp_addr *laddr,
1380					     int dif, int sdif);
1381bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1382			  const union sctp_addr *paddr, int dif, int sdif);
1383
1384int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1385		     const struct sctp_association *asoc,
1386		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1387		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1388int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1389		      const union sctp_addr *peer,
1390		      struct sctp_init_chunk *init, gfp_t gfp);
1391__u32 sctp_generate_tag(const struct sctp_endpoint *);
1392__u32 sctp_generate_tsn(const struct sctp_endpoint *);
1393
1394struct sctp_inithdr_host {
1395	__u32 init_tag;
1396	__u32 a_rwnd;
1397	__u16 num_outbound_streams;
1398	__u16 num_inbound_streams;
1399	__u32 initial_tsn;
1400};
1401
1402struct sctp_stream_priorities {
1403	/* List of priorities scheduled */
1404	struct list_head prio_sched;
1405	/* List of streams scheduled */
1406	struct list_head active;
1407	/* The next stream in line */
1408	struct sctp_stream_out_ext *next;
1409	__u16 prio;
1410	__u16 users;
1411};
1412
1413struct sctp_stream_out_ext {
1414	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1415	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1416	struct list_head outq; /* chunks enqueued by this stream */
1417	union {
1418		struct {
1419			/* Scheduled streams list */
1420			struct list_head prio_list;
1421			struct sctp_stream_priorities *prio_head;
1422		};
1423		/* Fields used by RR scheduler */
1424		struct {
1425			struct list_head rr_list;
1426		};
1427		struct {
1428			struct list_head fc_list;
1429			__u32 fc_length;
1430			__u16 fc_weight;
1431		};
1432	};
1433};
1434
1435struct sctp_stream_out {
1436	union {
1437		__u32 mid;
1438		__u16 ssn;
1439	};
1440	__u32 mid_uo;
1441	struct sctp_stream_out_ext *ext;
1442	__u8 state;
1443};
1444
1445struct sctp_stream_in {
1446	union {
1447		__u32 mid;
1448		__u16 ssn;
1449	};
1450	__u32 mid_uo;
1451	__u32 fsn;
1452	__u32 fsn_uo;
1453	char pd_mode;
1454	char pd_mode_uo;
1455};
1456
1457struct sctp_stream {
1458	GENRADIX(struct sctp_stream_out) out;
1459	GENRADIX(struct sctp_stream_in)	in;
1460
1461	__u16 outcnt;
1462	__u16 incnt;
1463	/* Current stream being sent, if any */
1464	struct sctp_stream_out *out_curr;
1465	union {
1466		/* Fields used by priority scheduler */
1467		struct {
1468			/* List of priorities scheduled */
1469			struct list_head prio_list;
1470		};
1471		/* Fields used by RR scheduler */
1472		struct {
1473			/* List of streams scheduled */
1474			struct list_head rr_list;
1475			/* The next stream in line */
1476			struct sctp_stream_out_ext *rr_next;
1477		};
1478		struct {
1479			struct list_head fc_list;
1480		};
1481	};
1482	struct sctp_stream_interleave *si;
1483};
1484
1485static inline struct sctp_stream_out *sctp_stream_out(
1486	struct sctp_stream *stream,
1487	__u16 sid)
1488{
1489	return genradix_ptr(&stream->out, sid);
1490}
1491
1492static inline struct sctp_stream_in *sctp_stream_in(
1493	struct sctp_stream *stream,
1494	__u16 sid)
1495{
1496	return genradix_ptr(&stream->in, sid);
1497}
1498
1499#define SCTP_SO(s, i) sctp_stream_out((s), (i))
1500#define SCTP_SI(s, i) sctp_stream_in((s), (i))
1501
1502#define SCTP_STREAM_CLOSED		0x00
1503#define SCTP_STREAM_OPEN		0x01
1504
1505static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1506{
1507	return stream->si->data_chunk_len;
1508}
1509
1510static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1511{
1512	return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1513}
1514
1515static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1516{
1517	return stream->si->ftsn_chunk_len;
1518}
1519
1520static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1521{
1522	return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1523}
1524
1525/* SCTP_GET_ASSOC_STATS counters */
1526struct sctp_priv_assoc_stats {
1527	/* Maximum observed rto in the association during subsequent
1528	 * observations. Value is set to 0 if no RTO measurement took place
1529	 * The transport where the max_rto was observed is returned in
1530	 * obs_rto_ipaddr
1531	 */
1532	struct sockaddr_storage obs_rto_ipaddr;
1533	__u64 max_obs_rto;
1534	/* Total In and Out SACKs received and sent */
1535	__u64 isacks;
1536	__u64 osacks;
1537	/* Total In and Out packets received and sent */
1538	__u64 opackets;
1539	__u64 ipackets;
1540	/* Total retransmitted chunks */
1541	__u64 rtxchunks;
1542	/* TSN received > next expected */
1543	__u64 outofseqtsns;
1544	/* Duplicate Chunks received */
1545	__u64 idupchunks;
1546	/* Gap Ack Blocks received */
1547	__u64 gapcnt;
1548	/* Unordered data chunks sent and received */
1549	__u64 ouodchunks;
1550	__u64 iuodchunks;
1551	/* Ordered data chunks sent and received */
1552	__u64 oodchunks;
1553	__u64 iodchunks;
1554	/* Control chunks sent and received */
1555	__u64 octrlchunks;
1556	__u64 ictrlchunks;
1557};
1558
1559/* RFC2960
1560 *
1561 * 12. Recommended Transmission Control Block (TCB) Parameters
1562 *
1563 * This section details a recommended set of parameters that should
1564 * be contained within the TCB for an implementation. This section is
1565 * for illustrative purposes and should not be deemed as requirements
1566 * on an implementation or as an exhaustive list of all parameters
1567 * inside an SCTP TCB. Each implementation may need its own additional
1568 * parameters for optimization.
1569 */
1570
1571
1572/* Here we have information about each individual association. */
1573struct sctp_association {
1574
1575	/* A base structure common to endpoint and association.
1576	 * In this context, it represents the associations's view
1577	 * of the local endpoint of the association.
1578	 */
1579	struct sctp_ep_common base;
1580
1581	/* Associations on the same socket. */
1582	struct list_head asocs;
1583
1584	/* association id. */
1585	sctp_assoc_t assoc_id;
1586
1587	/* This is our parent endpoint.	 */
1588	struct sctp_endpoint *ep;
1589
1590	/* These are those association elements needed in the cookie.  */
1591	struct sctp_cookie c;
1592
1593	/* This is all information about our peer.  */
1594	struct {
1595		/* transport_addr_list
1596		 *
1597		 * Peer	       : A list of SCTP transport addresses that the
1598		 * Transport   : peer is bound to. This information is derived
1599		 * Address     : from the INIT or INIT ACK and is used to
1600		 * List	       : associate an inbound packet with a given
1601		 *	       : association. Normally this information is
1602		 *	       : hashed or keyed for quick lookup and access
1603		 *	       : of the TCB.
1604		 *	       : The list is also initialized with the list
1605		 *	       : of addresses passed with the sctp_connectx()
1606		 *	       : call.
1607		 *
1608		 * It is a list of SCTP_transport's.
1609		 */
1610		struct list_head transport_addr_list;
1611
1612		/* rwnd
1613		 *
1614		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1615		 */
1616		__u32 rwnd;
1617
1618		/* transport_count
1619		 *
1620		 * Peer        : A count of the number of peer addresses
1621		 * Transport   : in the Peer Transport Address List.
1622		 * Address     :
1623		 * Count       :
1624		 */
1625		__u16 transport_count;
1626
1627		/* port
1628		 *   The transport layer port number.
1629		 */
1630		__u16 port;
1631
1632		/* primary_path
1633		 *
1634		 * Primary     : This is the current primary destination
1635		 * Path	       : transport address of the peer endpoint.  It
1636		 *	       : may also specify a source transport address
1637		 *	       : on this endpoint.
1638		 *
1639		 * All of these paths live on transport_addr_list.
1640		 *
1641		 * At the bakeoffs, we discovered that the intent of
1642		 * primaryPath is that it only changes when the ULP
1643		 * asks to have it changed.  We add the activePath to
1644		 * designate the connection we are currently using to
1645		 * transmit new data and most control chunks.
1646		 */
1647		struct sctp_transport *primary_path;
1648
1649		/* Cache the primary path address here, when we
1650		 * need a an address for msg_name.
1651		 */
1652		union sctp_addr primary_addr;
1653
1654		/* active_path
1655		 *   The path that we are currently using to
1656		 *   transmit new data and most control chunks.
1657		 */
1658		struct sctp_transport *active_path;
1659
1660		/* retran_path
1661		 *
1662		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1663		 * ...
1664		 * Furthermore, when its peer is multi-homed, an
1665		 * endpoint SHOULD try to retransmit a chunk to an
1666		 * active destination transport address that is
1667		 * different from the last destination address to
1668		 * which the DATA chunk was sent.
1669		 */
1670		struct sctp_transport *retran_path;
1671
1672		/* Pointer to last transport I have sent on.  */
1673		struct sctp_transport *last_sent_to;
1674
1675		/* This is the last transport I have received DATA on.	*/
1676		struct sctp_transport *last_data_from;
1677
1678		/*
1679		 * Mapping  An array of bits or bytes indicating which out of
1680		 * Array    order TSN's have been received (relative to the
1681		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1682		 *	    order packets have been received, this array
1683		 *	    will be set to all zero. This structure may be
1684		 *	    in the form of a circular buffer or bit array.
1685		 *
1686		 * Last Rcvd   : This is the last TSN received in
1687		 * TSN	       : sequence. This value is set initially by
1688		 *	       : taking the peer's Initial TSN, received in
1689		 *	       : the INIT or INIT ACK chunk, and subtracting
1690		 *	       : one from it.
1691		 *
1692		 * Throughout most of the specification this is called the
1693		 * "Cumulative TSN ACK Point".	In this case, we
1694		 * ignore the advice in 12.2 in favour of the term
1695		 * used in the bulk of the text.  This value is hidden
1696		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1697		 */
1698		struct sctp_tsnmap tsn_map;
1699
1700		/* This mask is used to disable sending the ASCONF chunk
1701		 * with specified parameter to peer.
1702		 */
1703		__be16 addip_disabled_mask;
1704
1705		/* These are capabilities which our peer advertised.  */
1706		__u16	ecn_capable:1,      /* Can peer do ECN? */
1707			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1708			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1709			asconf_capable:1,   /* Does peer support ADDIP? */
1710			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1711			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1712			intl_capable:1,     /* Can peer do INTERLEAVE */
1713			auth_capable:1,     /* Is peer doing SCTP-AUTH? */
1714			/* sack_needed:
1715			 *   This flag indicates if the next received
1716			 *   packet is to be responded to with a
1717			 *   SACK. This is initialized to 0.  When a packet
1718			 *   is received sack_cnt is incremented. If this value
1719			 *   reaches 2 or more, a SACK is sent and the
1720			 *   value is reset to 0. Note: This is used only
1721			 *   when no DATA chunks are received out of
1722			 *   order.  When DATA chunks are out of order,
1723			 *   SACK's are not delayed (see Section 6).
1724			 */
1725			sack_needed:1,     /* Do we need to sack the peer? */
1726			sack_generation:1,
1727			zero_window_announced:1;
1728
1729		__u32	sack_cnt;
1730
1731		__u32   adaptation_ind;	 /* Adaptation Code point. */
1732
1733		struct sctp_inithdr_host i;
1734		void *cookie;
1735		int cookie_len;
1736
1737		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1738		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1739		 * Initial TSN Value minus 1
1740		 */
1741		__u32 addip_serial;
1742
1743		/* SCTP-AUTH: We need to know pears random number, hmac list
1744		 * and authenticated chunk list.  All that is part of the
1745		 * cookie and these are just pointers to those locations
1746		 */
1747		struct sctp_random_param *peer_random;
1748		struct sctp_chunks_param *peer_chunks;
1749		struct sctp_hmac_algo_param *peer_hmacs;
1750	} peer;
1751
1752	/* State       : A state variable indicating what state the
1753	 *	       : association is in, i.e. COOKIE-WAIT,
1754	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1755	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1756	 *
1757	 *		Note: No "CLOSED" state is illustrated since if a
1758	 *		association is "CLOSED" its TCB SHOULD be removed.
1759	 *
1760	 *		In this implementation we DO have a CLOSED
1761	 *		state which is used during initiation and shutdown.
1762	 *
1763	 *		State takes values from SCTP_STATE_*.
1764	 */
1765	enum sctp_state state;
1766
1767	/* Overall     : The overall association error count.
1768	 * Error Count : [Clear this any time I get something.]
1769	 */
1770	int overall_error_count;
1771
1772	/* The cookie life I award for any cookie.  */
1773	ktime_t cookie_life;
1774
1775	/* These are the association's initial, max, and min RTO values.
1776	 * These values will be initialized by system defaults, but can
1777	 * be modified via the SCTP_RTOINFO socket option.
1778	 */
1779	unsigned long rto_initial;
1780	unsigned long rto_max;
1781	unsigned long rto_min;
1782
1783	/* Maximum number of new data packets that can be sent in a burst.  */
1784	int max_burst;
1785
1786	/* This is the max_retrans value for the association.  This value will
1787	 * be initialized from system defaults, but can be
1788	 * modified by the SCTP_ASSOCINFO socket option.
1789	 */
1790	int max_retrans;
1791
1792	/* This is the partially failed retrans value for the transport
1793	 * and will be initialized from the assocs value.  This can be
1794	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1795	 */
1796	__u16 pf_retrans;
1797	/* Used for primary path switchover. */
1798	__u16 ps_retrans;
1799
1800	/* Maximum number of times the endpoint will retransmit INIT  */
1801	__u16 max_init_attempts;
1802
1803	/* How many times have we resent an INIT? */
1804	__u16 init_retries;
1805
1806	/* The largest timeout or RTO value to use in attempting an INIT */
1807	unsigned long max_init_timeo;
1808
1809	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1810	 * the destination address every heartbeat interval. This value
1811	 * will be inherited by all new transports.
1812	 */
1813	unsigned long hbinterval;
1814	unsigned long probe_interval;
1815
1816	__be16 encap_port;
1817
1818	/* This is the max_retrans value for new transports in the
1819	 * association.
1820	 */
1821	__u16 pathmaxrxt;
1822
1823	__u32 flowlabel;
1824	__u8  dscp;
1825
1826	/* Flag that path mtu update is pending */
1827	__u8   pmtu_pending;
1828
1829	/* Association : The smallest PMTU discovered for all of the
1830	 * PMTU	       : peer's transport addresses.
1831	 */
1832	__u32 pathmtu;
1833
1834	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1835	__u32 param_flags;
1836
1837	__u32 sackfreq;
1838	/* SACK delay timeout */
1839	unsigned long sackdelay;
1840
1841	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1842	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1843
1844	/* Transport to which SHUTDOWN chunk was last sent.  */
1845	struct sctp_transport *shutdown_last_sent_to;
1846
1847	/* Transport to which INIT chunk was last sent.  */
1848	struct sctp_transport *init_last_sent_to;
1849
1850	/* How many times have we resent a SHUTDOWN */
1851	int shutdown_retries;
1852
1853	/* Next TSN    : The next TSN number to be assigned to a new
1854	 *	       : DATA chunk.  This is sent in the INIT or INIT
1855	 *	       : ACK chunk to the peer and incremented each
1856	 *	       : time a DATA chunk is assigned a TSN
1857	 *	       : (normally just prior to transmit or during
1858	 *	       : fragmentation).
1859	 */
1860	__u32 next_tsn;
1861
1862	/*
1863	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1864	 * TSN	       : is set initially by taking the peer's Initial TSN,
1865	 *	       : received in the INIT or INIT ACK chunk, and
1866	 *	       : subtracting one from it.
1867	 *
1868	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1869	 */
1870
1871	__u32 ctsn_ack_point;
1872
1873	/* PR-SCTP Advanced.Peer.Ack.Point */
1874	__u32 adv_peer_ack_point;
1875
1876	/* Highest TSN that is acknowledged by incoming SACKs. */
1877	__u32 highest_sacked;
1878
1879	/* TSN marking the fast recovery exit point */
1880	__u32 fast_recovery_exit;
1881
1882	/* Flag to track the current fast recovery state */
1883	__u8 fast_recovery;
1884
1885	/* The number of unacknowledged data chunks.  Reported through
1886	 * the SCTP_STATUS sockopt.
1887	 */
1888	__u16 unack_data;
1889
1890	/* The total number of data chunks that we've had to retransmit
1891	 * as the result of a T3 timer expiration
1892	 */
1893	__u32 rtx_data_chunks;
1894
1895	/* This is the association's receive buffer space.  This value is used
1896	 * to set a_rwnd field in an INIT or a SACK chunk.
1897	 */
1898	__u32 rwnd;
1899
1900	/* This is the last advertised value of rwnd over a SACK chunk. */
1901	__u32 a_rwnd;
1902
1903	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1904	 * to slop over a maximum of the association's frag_point.
1905	 */
1906	__u32 rwnd_over;
1907
1908	/* Keeps treack of rwnd pressure.  This happens when we have
1909	 * a window, but not receive buffer (i.e small packets).  This one
1910	 * is releases slowly (1 PMTU at a time ).
1911	 */
1912	__u32 rwnd_press;
1913
1914	/* This is the sndbuf size in use for the association.
1915	 * This corresponds to the sndbuf size for the association,
1916	 * as specified in the sk->sndbuf.
1917	 */
1918	int sndbuf_used;
1919
1920	/* This is the amount of memory that this association has allocated
1921	 * in the receive path at any given time.
1922	 */
1923	atomic_t rmem_alloc;
1924
1925	/* This is the wait queue head for send requests waiting on
1926	 * the association sndbuf space.
1927	 */
1928	wait_queue_head_t	wait;
1929
1930	/* The message size at which SCTP fragmentation will occur. */
1931	__u32 frag_point;
1932	__u32 user_frag;
1933
1934	/* Counter used to count INIT errors. */
1935	int init_err_counter;
1936
1937	/* Count the number of INIT cycles (for doubling timeout). */
1938	int init_cycle;
1939
1940	/* Default send parameters. */
1941	__u16 default_stream;
1942	__u16 default_flags;
1943	__u32 default_ppid;
1944	__u32 default_context;
1945	__u32 default_timetolive;
1946
1947	/* Default receive parameters */
1948	__u32 default_rcv_context;
1949
1950	/* Stream arrays */
1951	struct sctp_stream stream;
1952
1953	/* All outbound chunks go through this structure.  */
1954	struct sctp_outq outqueue;
1955
1956	/* A smart pipe that will handle reordering and fragmentation,
1957	 * as well as handle passing events up to the ULP.
1958	 */
1959	struct sctp_ulpq ulpq;
1960
1961	/* Last TSN that caused an ECNE Chunk to be sent.  */
1962	__u32 last_ecne_tsn;
1963
1964	/* Last TSN that caused a CWR Chunk to be sent.	 */
1965	__u32 last_cwr_tsn;
1966
1967	/* How many duplicated TSNs have we seen?  */
1968	int numduptsns;
1969
1970	/* These are to support
1971	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1972	 *  and Enforcement of Flow and Message Limits"
1973	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1974	 * or "ADDIP" for short.
1975	 */
1976
1977
1978
1979	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1980	 *
1981	 * R1) One and only one ASCONF Chunk MAY be in transit and
1982	 * unacknowledged at any one time.  If a sender, after sending
1983	 * an ASCONF chunk, decides it needs to transfer another
1984	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1985	 * returns from the previous ASCONF Chunk before sending a
1986	 * subsequent ASCONF. Note this restriction binds each side,
1987	 * so at any time two ASCONF may be in-transit on any given
1988	 * association (one sent from each endpoint).
1989	 *
1990	 * [This is our one-and-only-one ASCONF in flight.  If we do
1991	 * not have an ASCONF in flight, this is NULL.]
1992	 */
1993	struct sctp_chunk *addip_last_asconf;
1994
1995	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1996	 *
1997	 * This is needed to implement items E1 - E4 of the updated
1998	 * spec.  Here is the justification:
1999	 *
2000	 * Since the peer may bundle multiple ASCONF chunks toward us,
2001	 * we now need the ability to cache multiple ACKs.  The section
2002	 * describes in detail how they are cached and cleaned up.
2003	 */
2004	struct list_head asconf_ack_list;
2005
2006	/* These ASCONF chunks are waiting to be sent.
2007	 *
2008	 * These chunks can't be pushed to outqueue until receiving
2009	 * ASCONF_ACK for the previous ASCONF indicated by
2010	 * addip_last_asconf, so as to guarantee that only one ASCONF
2011	 * is in flight at any time.
2012	 *
2013	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
2014	 *
2015	 * In defining the ASCONF Chunk transfer procedures, it is
2016	 * essential that these transfers MUST NOT cause congestion
2017	 * within the network.	To achieve this, we place these
2018	 * restrictions on the transfer of ASCONF Chunks:
2019	 *
2020	 * R1) One and only one ASCONF Chunk MAY be in transit and
2021	 * unacknowledged at any one time.  If a sender, after sending
2022	 * an ASCONF chunk, decides it needs to transfer another
2023	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
2024	 * returns from the previous ASCONF Chunk before sending a
2025	 * subsequent ASCONF. Note this restriction binds each side,
2026	 * so at any time two ASCONF may be in-transit on any given
2027	 * association (one sent from each endpoint).
2028	 *
2029	 *
2030	 * [I really think this is EXACTLY the sort of intelligence
2031	 *  which already resides in sctp_outq.	 Please move this
2032	 *  queue and its supporting logic down there.	--piggy]
2033	 */
2034	struct list_head addip_chunk_list;
2035
2036	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2037	 *
2038	 * A2) A serial number should be assigned to the Chunk. The
2039	 * serial number SHOULD be a monotonically increasing
2040	 * number. The serial number SHOULD be initialized at
2041	 * the start of the association to the same value as the
2042	 * Initial TSN and every time a new ASCONF chunk is created
2043	 * it is incremented by one after assigning the serial number
2044	 * to the newly created chunk.
2045	 *
2046	 * ADDIP
2047	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
2048	 *
2049	 * Serial Number : 32 bits (unsigned integer)
2050	 *
2051	 * This value represents a Serial Number for the ASCONF
2052	 * Chunk. The valid range of Serial Number is from 0 to
2053	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
2054	 * after reaching 4294967295.
2055	 */
2056	__u32 addip_serial;
2057	int src_out_of_asoc_ok;
2058	union sctp_addr *asconf_addr_del_pending;
2059	struct sctp_transport *new_transport;
2060
2061	/* SCTP AUTH: list of the endpoint shared keys.  These
2062	 * keys are provided out of band by the user application
2063	 * and can't change during the lifetime of the association
2064	 */
2065	struct list_head endpoint_shared_keys;
2066
2067	/* SCTP AUTH:
2068	 * The current generated association shared key (secret)
2069	 */
2070	struct sctp_auth_bytes *asoc_shared_key;
2071	struct sctp_shared_key *shkey;
2072
2073	/* SCTP AUTH: hmac id of the first peer requested algorithm
2074	 * that we support.
2075	 */
2076	__u16 default_hmac_id;
2077
2078	__u16 active_key_id;
2079
2080	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
2081	     temp:1,		/* Is it a temporary association? */
2082	     pf_expose:2,       /* Expose pf state? */
2083	     force_delay:1;
2084
2085	__u8 strreset_enable;
2086	__u8 strreset_outstanding; /* request param count on the fly */
2087
2088	__u32 strreset_outseq; /* Update after receiving response */
2089	__u32 strreset_inseq; /* Update after receiving request */
2090	__u32 strreset_result[2]; /* save the results of last 2 responses */
2091
2092	struct sctp_chunk *strreset_chunk; /* save request chunk */
2093
2094	struct sctp_priv_assoc_stats stats;
2095
2096	int sent_cnt_removable;
2097
2098	__u16 subscribe;
2099
2100	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2101	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2102
2103	/* Security identifiers from incoming (INIT). These are set by
2104	 * security_sctp_assoc_request(). These will only be used by
2105	 * SCTP TCP type sockets and peeled off connections as they
2106	 * cause a new socket to be generated. security_sctp_sk_clone()
2107	 * will then plug these into the new socket.
2108	 */
2109
2110	u32 secid;
2111	u32 peer_secid;
2112
2113	struct rcu_head rcu;
2114};
2115
2116
2117/* An eyecatcher for determining if we are really looking at an
2118 * association data structure.
2119 */
2120enum {
2121	SCTP_ASSOC_EYECATCHER = 0xa550c123,
2122};
2123
2124/* Recover the outer association structure. */
2125static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2126{
2127	struct sctp_association *asoc;
2128
2129	asoc = container_of(base, struct sctp_association, base);
2130	return asoc;
2131}
2132
2133/* These are function signatures for manipulating associations.	 */
2134
2135
2136struct sctp_association *
2137sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2138		     enum sctp_scope scope, gfp_t gfp);
2139void sctp_association_free(struct sctp_association *);
2140void sctp_association_put(struct sctp_association *);
2141void sctp_association_hold(struct sctp_association *);
2142
2143struct sctp_transport *sctp_assoc_choose_alter_transport(
2144	struct sctp_association *, struct sctp_transport *);
2145void sctp_assoc_update_retran_path(struct sctp_association *);
2146struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2147					  const union sctp_addr *);
2148int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2149			    const union sctp_addr *laddr);
2150struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2151				     const union sctp_addr *address,
2152				     const gfp_t gfp,
2153				     const int peer_state);
2154void sctp_assoc_del_peer(struct sctp_association *asoc,
2155			 const union sctp_addr *addr);
2156void sctp_assoc_rm_peer(struct sctp_association *asoc,
2157			 struct sctp_transport *peer);
2158void sctp_assoc_control_transport(struct sctp_association *asoc,
2159				  struct sctp_transport *transport,
2160				  enum sctp_transport_cmd command,
2161				  sctp_sn_error_t error);
2162struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2163void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2164int sctp_assoc_update(struct sctp_association *old,
2165		      struct sctp_association *new);
2166
2167__u32 sctp_association_get_next_tsn(struct sctp_association *);
2168
2169void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2170void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2171void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2172void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2173void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2174void sctp_assoc_set_primary(struct sctp_association *,
2175			    struct sctp_transport *);
2176void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2177				    struct sctp_transport *);
2178int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2179				     enum sctp_scope scope, gfp_t gfp);
2180int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2181					 struct sctp_cookie*,
2182					 gfp_t gfp);
2183int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2184void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2185struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2186					const struct sctp_association *asoc,
2187					__be32 serial);
2188void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2189
2190int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2191			const union sctp_addr *ss2);
2192struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2193
2194/* A convenience structure to parse out SCTP specific CMSGs. */
2195struct sctp_cmsgs {
2196	struct sctp_initmsg *init;
2197	struct sctp_sndrcvinfo *srinfo;
2198	struct sctp_sndinfo *sinfo;
2199	struct sctp_prinfo *prinfo;
2200	struct sctp_authinfo *authinfo;
2201	struct msghdr *addrs_msg;
2202};
2203
2204/* Structure for tracking memory objects */
2205struct sctp_dbg_objcnt_entry {
2206	char *label;
2207	atomic_t *counter;
2208};
2209
2210#endif /* __sctp_structs_h__ */