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
 245static inline struct sctp_sock *sctp_sk(const struct sock *sk)
 246{
 247       return (struct sctp_sock *)sk;
 248}
 249
 250static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
 251{
 252       return (struct sock *)sp;
 253}
 254
 255#if IS_ENABLED(CONFIG_IPV6)
 256struct 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
 272struct 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. */
 340struct 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 */
 350union 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 */
 359union 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 */
 384struct 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
 392int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
 393		     gfp_t gfp);
 394int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
 395void sctp_stream_free(struct sctp_stream *stream);
 396void sctp_stream_clear(struct sctp_stream *stream);
 397void 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 */
 435struct 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
 492struct sctp_af *sctp_get_af_specific(sa_family_t);
 493int sctp_register_af(struct sctp_af *);
 494
 495/* Protocol family functions. */
 496struct 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 */
 520struct 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
 534struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
 535					    struct sctp_sndrcvinfo *,
 536					    struct iov_iter *);
 537void sctp_datamsg_free(struct sctp_datamsg *);
 538void sctp_datamsg_put(struct sctp_datamsg *);
 539void sctp_chunk_fail(struct sctp_chunk *, int error);
 540int 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 */
 550struct 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)
 668void sctp_chunk_hold(struct sctp_chunk *);
 669void sctp_chunk_put(struct sctp_chunk *);
 670int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
 671			  struct iov_iter *from);
 672void sctp_chunk_free(struct sctp_chunk *);
 673void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
 674struct sctp_chunk *sctp_chunkify(struct sk_buff *,
 675				 const struct sctp_association *,
 676				 struct sock *, gfp_t gfp);
 677void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
 678		     union sctp_addr *);
 679const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
 680
 681static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
 682{
 683	return ntohs(ch->subh.data_hdr->stream);
 684}
 685
 686enum {
 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.  */
 693struct 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 */
 706struct 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
 738void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
 739		      __u16 sport, __u16 dport);
 740void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
 741enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
 742					  struct sctp_chunk *chunk,
 743					  int one_packet, gfp_t gfp);
 744enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
 745					struct sctp_chunk *chunk);
 746int sctp_packet_transmit(struct sctp_packet *, gfp_t);
 747void sctp_packet_free(struct sctp_packet *);
 748
 749static 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 */
 774struct 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
1001struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
1002					  gfp_t);
1003void sctp_transport_set_owner(struct sctp_transport *,
1004			      struct sctp_association *);
1005void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1006			  struct sctp_sock *);
1007void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
1008void sctp_transport_free(struct sctp_transport *);
1009void sctp_transport_reset_t3_rtx(struct sctp_transport *);
1010void sctp_transport_reset_hb_timer(struct sctp_transport *);
1011void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
1012void sctp_transport_reset_probe_timer(struct sctp_transport *transport);
1013void sctp_transport_reset_raise_timer(struct sctp_transport *transport);
1014int sctp_transport_hold(struct sctp_transport *);
1015void sctp_transport_put(struct sctp_transport *);
1016void sctp_transport_update_rto(struct sctp_transport *, __u32);
1017void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1018void sctp_transport_lower_cwnd(struct sctp_transport *t,
1019			       enum sctp_lower_cwnd reason);
1020void sctp_transport_burst_limited(struct sctp_transport *);
1021void sctp_transport_burst_reset(struct sctp_transport *);
1022unsigned long sctp_transport_timeout(struct sctp_transport *);
1023void sctp_transport_reset(struct sctp_transport *t);
1024bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1025void sctp_transport_immediate_rtx(struct sctp_transport *);
1026void sctp_transport_dst_release(struct sctp_transport *t);
1027void sctp_transport_dst_confirm(struct sctp_transport *t);
1028void sctp_transport_pl_send(struct sctp_transport *t);
1029bool 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 */
1035struct 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
1051void sctp_inq_init(struct sctp_inq *);
1052void sctp_inq_free(struct sctp_inq *);
1053void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1054struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1055struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1056void 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 */
1077struct 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
1119void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1120void sctp_outq_teardown(struct sctp_outq *);
1121void sctp_outq_free(struct sctp_outq*);
1122void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1123int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1124int sctp_outq_is_empty(const struct sctp_outq *);
1125void sctp_outq_restart(struct sctp_outq *);
1126
1127void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1128		     enum sctp_retransmit_reason reason);
1129void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1130void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1131void sctp_prsctp_prune(struct sctp_association *asoc,
1132		       struct sctp_sndrcvinfo *sinfo, int msg_len);
1133void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1134/* Uncork and flush an outqueue.  */
1135static inline void sctp_outq_cork(struct sctp_outq *q)
1136{
1137	q->cork = 1;
1138}
1139
1140/* SCTP skb control block.
1141 * sctp_input_cb is currently used on rx and sock rx queue
1142 */
1143struct sctp_input_cb {
1144	union {
1145		struct inet_skb_parm    h4;
1146#if IS_ENABLED(CONFIG_IPV6)
1147		struct inet6_skb_parm   h6;
1148#endif
1149	} header;
1150	struct sctp_chunk *chunk;
1151	struct sctp_af *af;
1152	__be16 encap_port;
1153};
1154#define SCTP_INPUT_CB(__skb)	((struct sctp_input_cb *)&((__skb)->cb[0]))
1155
1156struct sctp_output_cb {
1157	struct sk_buff *last;
1158};
1159#define SCTP_OUTPUT_CB(__skb)	((struct sctp_output_cb *)&((__skb)->cb[0]))
1160
1161static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1162{
1163	const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1164
1165	return chunk->head_skb ? : skb;
1166}
1167
1168/* These bind address data fields common between endpoints and associations */
1169struct sctp_bind_addr {
1170
1171	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1172	 *
1173	 * SCTP Port:	The local SCTP port number the endpoint is
1174	 *		bound to.
1175	 */
1176	__u16 port;
1177
1178	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1179	 *
1180	 * Address List: The list of IP addresses that this instance
1181	 *	has bound.  This information is passed to one's
1182	 *	peer(s) in INIT and INIT ACK chunks.
1183	 */
1184	struct list_head address_list;
1185};
1186
1187void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1188void sctp_bind_addr_free(struct sctp_bind_addr *);
1189int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1190			const struct sctp_bind_addr *src,
1191			enum sctp_scope scope, gfp_t gfp,
1192			int flags);
1193int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1194			const struct sctp_bind_addr *src,
1195			gfp_t gfp);
1196int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1197		       int new_size, __u8 addr_state, gfp_t gfp);
1198int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1199int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1200			 struct sctp_sock *);
1201int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1202			 struct sctp_sock *, struct sctp_sock *);
1203int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1204			 const union sctp_addr *addr);
1205int sctp_bind_addrs_check(struct sctp_sock *sp,
1206			  struct sctp_sock *sp2, int cnt2);
1207union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1208					const union sctp_addr	*addrs,
1209					int			addrcnt,
1210					struct sctp_sock	*opt);
1211union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1212					 int *addrs_len,
1213					 gfp_t gfp);
1214int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1215			   __u16 port, gfp_t gfp);
1216
1217enum sctp_scope sctp_scope(const union sctp_addr *addr);
1218int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1219		  const enum sctp_scope scope);
1220int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1221int sctp_is_ep_boundall(struct sock *sk);
1222
1223
1224/* What type of endpoint?  */
1225enum sctp_endpoint_type {
1226	SCTP_EP_TYPE_SOCKET,
1227	SCTP_EP_TYPE_ASSOCIATION,
1228};
1229
1230/*
1231 * A common base class to bridge the implmentation view of a
1232 * socket (usually listening) endpoint versus an association's
1233 * local endpoint.
1234 * This common structure is useful for several purposes:
1235 *   1) Common interface for lookup routines.
1236 *	a) Subfunctions work for either endpoint or association
1237 *	b) Single interface to lookup allows hiding the lookup lock rather
1238 *	   than acquiring it externally.
1239 *   2) Common interface for the inbound chunk handling/state machine.
1240 *   3) Common object handling routines for reference counting, etc.
1241 *   4) Disentangle association lookup from endpoint lookup, where we
1242 *	do not have to find our endpoint to find our association.
1243 *
1244 */
1245
1246struct sctp_ep_common {
 
 
 
 
1247	/* Runtime type information.  What kind of endpoint is this? */
1248	enum sctp_endpoint_type type;
1249
1250	/* Some fields to help us manage this object.
1251	 *   refcnt   - Reference count access to this object.
1252	 *   dead     - Do not attempt to use this object.
1253	 */
1254	refcount_t    refcnt;
1255	bool	    dead;
1256
1257	/* What socket does this endpoint belong to?  */
1258	struct sock *sk;
1259
1260	/* Cache netns and it won't change once set */
1261	struct net *net;
1262
1263	/* This is where we receive inbound chunks.  */
1264	struct sctp_inq	  inqueue;
1265
1266	/* This substructure includes the defining parameters of the
1267	 * endpoint:
1268	 * bind_addr.port is our shared port number.
1269	 * bind_addr.address_list is our set of local IP addresses.
1270	 */
1271	struct sctp_bind_addr bind_addr;
1272};
1273
1274
1275/* RFC Section 1.4 Key Terms
1276 *
1277 * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1278 *   multi-homed host, an SCTP endpoint is represented to its peers as a
1279 *   combination of a set of eligible destination transport addresses to
1280 *   which SCTP packets can be sent and a set of eligible source
1281 *   transport addresses from which SCTP packets can be received.
1282 *   All transport addresses used by an SCTP endpoint must use the
1283 *   same port number, but can use multiple IP addresses. A transport
1284 *   address used by an SCTP endpoint must not be used by another
1285 *   SCTP endpoint. In other words, a transport address is unique
1286 *   to an SCTP endpoint.
1287 *
1288 * From an implementation perspective, each socket has one of these.
1289 * A TCP-style socket will have exactly one association on one of
1290 * these.  An UDP-style socket will have multiple associations hanging
1291 * off one of these.
1292 */
1293
1294struct sctp_endpoint {
1295	/* Common substructure for endpoint and association. */
1296	struct sctp_ep_common base;
1297
1298	/* Fields to help us manage our entries in the hash tables. */
1299	struct hlist_node node;
1300	int hashent;
1301
1302	/* Associations: A list of current associations and mappings
1303	 *	      to the data consumers for each association. This
1304	 *	      may be in the form of a hash table or other
1305	 *	      implementation dependent structure. The data
1306	 *	      consumers may be process identification
1307	 *	      information such as file descriptors, named pipe
1308	 *	      pointer, or table pointers dependent on how SCTP
1309	 *	      is implemented.
1310	 */
1311	/* This is really a list of struct sctp_association entries. */
1312	struct list_head asocs;
1313
1314	/* Secret Key: A secret key used by this endpoint to compute
1315	 *	      the MAC.	This SHOULD be a cryptographic quality
1316	 *	      random number with a sufficient length.
1317	 *	      Discussion in [RFC1750] can be helpful in
1318	 *	      selection of the key.
1319	 */
1320	__u8 secret_key[SCTP_SECRET_SIZE];
1321
1322 	/* digest:  This is a digest of the sctp cookie.  This field is
1323 	 * 	    only used on the receive path when we try to validate
1324 	 * 	    that the cookie has not been tampered with.  We put
1325 	 * 	    this here so we pre-allocate this once and can re-use
1326 	 * 	    on every receive.
1327 	 */
1328 	__u8 *digest;
1329 
1330	/* sendbuf acct. policy.	*/
1331	__u32 sndbuf_policy;
1332
1333	/* rcvbuf acct. policy.	*/
1334	__u32 rcvbuf_policy;
1335
1336	/* SCTP AUTH: array of the HMACs that will be allocated
1337	 * we need this per association so that we don't serialize
1338	 */
1339	struct crypto_shash **auth_hmacs;
1340
1341	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1342	 struct sctp_hmac_algo_param *auth_hmacs_list;
1343
1344	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1345	struct sctp_chunks_param *auth_chunk_list;
1346
1347	/* SCTP-AUTH: endpoint shared keys */
1348	struct list_head endpoint_shared_keys;
1349	__u16 active_key_id;
1350	__u8  ecn_enable:1,
1351	      auth_enable:1,
1352	      intl_enable:1,
1353	      prsctp_enable:1,
1354	      asconf_enable:1,
1355	      reconf_enable:1;
1356
1357	__u8  strreset_enable;
1358	struct rcu_head rcu;
 
 
 
 
 
 
 
 
 
1359};
1360
1361/* Recover the outter endpoint structure. */
1362static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1363{
1364	struct sctp_endpoint *ep;
1365
1366	ep = container_of(base, struct sctp_endpoint, base);
1367	return ep;
1368}
1369
1370/* These are function signatures for manipulating endpoints.  */
1371struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1372void sctp_endpoint_free(struct sctp_endpoint *);
1373void sctp_endpoint_put(struct sctp_endpoint *);
1374int sctp_endpoint_hold(struct sctp_endpoint *ep);
1375void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1376struct sctp_association *sctp_endpoint_lookup_assoc(
1377	const struct sctp_endpoint *ep,
1378	const union sctp_addr *paddr,
1379	struct sctp_transport **);
1380bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1381				 const union sctp_addr *paddr);
1382struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
1383					     struct net *net,
1384					     const union sctp_addr *laddr,
1385					     int dif, int sdif);
1386bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1387			  const union sctp_addr *paddr, int dif, int sdif);
1388
1389int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1390		     const struct sctp_association *asoc,
1391		     enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1392		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1393int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1394		      const union sctp_addr *peer,
1395		      struct sctp_init_chunk *init, gfp_t gfp);
1396__u32 sctp_generate_tag(const struct sctp_endpoint *);
1397__u32 sctp_generate_tsn(const struct sctp_endpoint *);
1398
1399struct sctp_inithdr_host {
1400	__u32 init_tag;
1401	__u32 a_rwnd;
1402	__u16 num_outbound_streams;
1403	__u16 num_inbound_streams;
1404	__u32 initial_tsn;
1405};
1406
1407struct sctp_stream_priorities {
1408	/* List of priorities scheduled */
1409	struct list_head prio_sched;
1410	/* List of streams scheduled */
1411	struct list_head active;
1412	/* The next stream in line */
1413	struct sctp_stream_out_ext *next;
1414	__u16 prio;
1415};
1416
1417struct sctp_stream_out_ext {
1418	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1419	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1420	struct list_head outq; /* chunks enqueued by this stream */
1421	union {
1422		struct {
1423			/* Scheduled streams list */
1424			struct list_head prio_list;
1425			struct sctp_stream_priorities *prio_head;
1426		};
1427		/* Fields used by RR scheduler */
1428		struct {
1429			struct list_head rr_list;
1430		};
1431	};
1432};
1433
1434struct sctp_stream_out {
1435	union {
1436		__u32 mid;
1437		__u16 ssn;
1438	};
1439	__u32 mid_uo;
1440	struct sctp_stream_out_ext *ext;
1441	__u8 state;
1442};
1443
1444struct sctp_stream_in {
1445	union {
1446		__u32 mid;
1447		__u16 ssn;
1448	};
1449	__u32 mid_uo;
1450	__u32 fsn;
1451	__u32 fsn_uo;
1452	char pd_mode;
1453	char pd_mode_uo;
1454};
1455
1456struct sctp_stream {
1457	GENRADIX(struct sctp_stream_out) out;
1458	GENRADIX(struct sctp_stream_in)	in;
1459
1460	__u16 outcnt;
1461	__u16 incnt;
1462	/* Current stream being sent, if any */
1463	struct sctp_stream_out *out_curr;
1464	union {
1465		/* Fields used by priority scheduler */
1466		struct {
1467			/* List of priorities scheduled */
1468			struct list_head prio_list;
1469		};
1470		/* Fields used by RR scheduler */
1471		struct {
1472			/* List of streams scheduled */
1473			struct list_head rr_list;
1474			/* The next stream in line */
1475			struct sctp_stream_out_ext *rr_next;
1476		};
1477	};
1478	struct sctp_stream_interleave *si;
1479};
1480
1481static inline struct sctp_stream_out *sctp_stream_out(
1482	struct sctp_stream *stream,
1483	__u16 sid)
1484{
1485	return genradix_ptr(&stream->out, sid);
1486}
1487
1488static inline struct sctp_stream_in *sctp_stream_in(
1489	struct sctp_stream *stream,
1490	__u16 sid)
1491{
1492	return genradix_ptr(&stream->in, sid);
1493}
1494
1495#define SCTP_SO(s, i) sctp_stream_out((s), (i))
1496#define SCTP_SI(s, i) sctp_stream_in((s), (i))
1497
1498#define SCTP_STREAM_CLOSED		0x00
1499#define SCTP_STREAM_OPEN		0x01
1500
1501static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1502{
1503	return stream->si->data_chunk_len;
1504}
1505
1506static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1507{
1508	return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1509}
1510
1511static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1512{
1513	return stream->si->ftsn_chunk_len;
1514}
1515
1516static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1517{
1518	return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1519}
1520
1521/* SCTP_GET_ASSOC_STATS counters */
1522struct sctp_priv_assoc_stats {
1523	/* Maximum observed rto in the association during subsequent
1524	 * observations. Value is set to 0 if no RTO measurement took place
1525	 * The transport where the max_rto was observed is returned in
1526	 * obs_rto_ipaddr
1527	 */
1528	struct sockaddr_storage obs_rto_ipaddr;
1529	__u64 max_obs_rto;
1530	/* Total In and Out SACKs received and sent */
1531	__u64 isacks;
1532	__u64 osacks;
1533	/* Total In and Out packets received and sent */
1534	__u64 opackets;
1535	__u64 ipackets;
1536	/* Total retransmitted chunks */
1537	__u64 rtxchunks;
1538	/* TSN received > next expected */
1539	__u64 outofseqtsns;
1540	/* Duplicate Chunks received */
1541	__u64 idupchunks;
1542	/* Gap Ack Blocks received */
1543	__u64 gapcnt;
1544	/* Unordered data chunks sent and received */
1545	__u64 ouodchunks;
1546	__u64 iuodchunks;
1547	/* Ordered data chunks sent and received */
1548	__u64 oodchunks;
1549	__u64 iodchunks;
1550	/* Control chunks sent and received */
1551	__u64 octrlchunks;
1552	__u64 ictrlchunks;
1553};
1554
1555/* RFC2960
1556 *
1557 * 12. Recommended Transmission Control Block (TCB) Parameters
1558 *
1559 * This section details a recommended set of parameters that should
1560 * be contained within the TCB for an implementation. This section is
1561 * for illustrative purposes and should not be deemed as requirements
1562 * on an implementation or as an exhaustive list of all parameters
1563 * inside an SCTP TCB. Each implementation may need its own additional
1564 * parameters for optimization.
1565 */
1566
1567
1568/* Here we have information about each individual association. */
1569struct sctp_association {
1570
1571	/* A base structure common to endpoint and association.
1572	 * In this context, it represents the associations's view
1573	 * of the local endpoint of the association.
1574	 */
1575	struct sctp_ep_common base;
1576
1577	/* Associations on the same socket. */
1578	struct list_head asocs;
1579
1580	/* association id. */
1581	sctp_assoc_t assoc_id;
1582
1583	/* This is our parent endpoint.	 */
1584	struct sctp_endpoint *ep;
1585
1586	/* These are those association elements needed in the cookie.  */
1587	struct sctp_cookie c;
1588
1589	/* This is all information about our peer.  */
1590	struct {
1591		/* transport_addr_list
1592		 *
1593		 * Peer	       : A list of SCTP transport addresses that the
1594		 * Transport   : peer is bound to. This information is derived
1595		 * Address     : from the INIT or INIT ACK and is used to
1596		 * List	       : associate an inbound packet with a given
1597		 *	       : association. Normally this information is
1598		 *	       : hashed or keyed for quick lookup and access
1599		 *	       : of the TCB.
1600		 *	       : The list is also initialized with the list
1601		 *	       : of addresses passed with the sctp_connectx()
1602		 *	       : call.
1603		 *
1604		 * It is a list of SCTP_transport's.
1605		 */
1606		struct list_head transport_addr_list;
1607
1608		/* rwnd
1609		 *
1610		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1611		 */
1612		__u32 rwnd;
1613
1614		/* transport_count
1615		 *
1616		 * Peer        : A count of the number of peer addresses
1617		 * Transport   : in the Peer Transport Address List.
1618		 * Address     :
1619		 * Count       :
1620		 */
1621		__u16 transport_count;
1622
1623		/* port
1624		 *   The transport layer port number.
1625		 */
1626		__u16 port;
1627
1628		/* primary_path
1629		 *
1630		 * Primary     : This is the current primary destination
1631		 * Path	       : transport address of the peer endpoint.  It
1632		 *	       : may also specify a source transport address
1633		 *	       : on this endpoint.
1634		 *
1635		 * All of these paths live on transport_addr_list.
1636		 *
1637		 * At the bakeoffs, we discovered that the intent of
1638		 * primaryPath is that it only changes when the ULP
1639		 * asks to have it changed.  We add the activePath to
1640		 * designate the connection we are currently using to
1641		 * transmit new data and most control chunks.
1642		 */
1643		struct sctp_transport *primary_path;
1644
1645		/* Cache the primary path address here, when we
1646		 * need a an address for msg_name.
1647		 */
1648		union sctp_addr primary_addr;
1649
1650		/* active_path
1651		 *   The path that we are currently using to
1652		 *   transmit new data and most control chunks.
1653		 */
1654		struct sctp_transport *active_path;
1655
1656		/* retran_path
1657		 *
1658		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1659		 * ...
1660		 * Furthermore, when its peer is multi-homed, an
1661		 * endpoint SHOULD try to retransmit a chunk to an
1662		 * active destination transport address that is
1663		 * different from the last destination address to
1664		 * which the DATA chunk was sent.
1665		 */
1666		struct sctp_transport *retran_path;
1667
1668		/* Pointer to last transport I have sent on.  */
1669		struct sctp_transport *last_sent_to;
1670
1671		/* This is the last transport I have received DATA on.	*/
1672		struct sctp_transport *last_data_from;
1673
1674		/*
1675		 * Mapping  An array of bits or bytes indicating which out of
1676		 * Array    order TSN's have been received (relative to the
1677		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1678		 *	    order packets have been received, this array
1679		 *	    will be set to all zero. This structure may be
1680		 *	    in the form of a circular buffer or bit array.
1681		 *
1682		 * Last Rcvd   : This is the last TSN received in
1683		 * TSN	       : sequence. This value is set initially by
1684		 *	       : taking the peer's Initial TSN, received in
1685		 *	       : the INIT or INIT ACK chunk, and subtracting
1686		 *	       : one from it.
1687		 *
1688		 * Throughout most of the specification this is called the
1689		 * "Cumulative TSN ACK Point".	In this case, we
1690		 * ignore the advice in 12.2 in favour of the term
1691		 * used in the bulk of the text.  This value is hidden
1692		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1693		 */
1694		struct sctp_tsnmap tsn_map;
1695
1696		/* This mask is used to disable sending the ASCONF chunk
1697		 * with specified parameter to peer.
1698		 */
1699		__be16 addip_disabled_mask;
1700
1701		/* These are capabilities which our peer advertised.  */
1702		__u16	ecn_capable:1,      /* Can peer do ECN? */
1703			ipv4_address:1,     /* Peer understands IPv4 addresses? */
1704			ipv6_address:1,     /* Peer understands IPv6 addresses? */
1705			hostname_address:1, /* Peer understands DNS addresses? */
1706			asconf_capable:1,   /* Does peer support ADDIP? */
1707			prsctp_capable:1,   /* Can peer do PR-SCTP? */
1708			reconf_capable:1,   /* Can peer do RE-CONFIG? */
1709			intl_capable:1,     /* Can peer do INTERLEAVE */
1710			auth_capable:1,     /* Is peer doing SCTP-AUTH? */
1711			/* sack_needed:
1712			 *   This flag indicates if the next received
1713			 *   packet is to be responded to with a
1714			 *   SACK. This is initialized to 0.  When a packet
1715			 *   is received sack_cnt is incremented. If this value
1716			 *   reaches 2 or more, a SACK is sent and the
1717			 *   value is reset to 0. Note: This is used only
1718			 *   when no DATA chunks are received out of
1719			 *   order.  When DATA chunks are out of order,
1720			 *   SACK's are not delayed (see Section 6).
1721			 */
1722			sack_needed:1,     /* Do we need to sack the peer? */
1723			sack_generation:1,
1724			zero_window_announced:1;
1725
1726		__u32	sack_cnt;
1727
1728		__u32   adaptation_ind;	 /* Adaptation Code point. */
1729
1730		struct sctp_inithdr_host i;
1731		void *cookie;
1732		int cookie_len;
1733
1734		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1735		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1736		 * Initial TSN Value minus 1
1737		 */
1738		__u32 addip_serial;
1739
1740		/* SCTP-AUTH: We need to know pears random number, hmac list
1741		 * and authenticated chunk list.  All that is part of the
1742		 * cookie and these are just pointers to those locations
1743		 */
1744		struct sctp_random_param *peer_random;
1745		struct sctp_chunks_param *peer_chunks;
1746		struct sctp_hmac_algo_param *peer_hmacs;
1747	} peer;
1748
1749	/* State       : A state variable indicating what state the
1750	 *	       : association is in, i.e. COOKIE-WAIT,
1751	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1752	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1753	 *
1754	 *		Note: No "CLOSED" state is illustrated since if a
1755	 *		association is "CLOSED" its TCB SHOULD be removed.
1756	 *
1757	 *		In this implementation we DO have a CLOSED
1758	 *		state which is used during initiation and shutdown.
1759	 *
1760	 *		State takes values from SCTP_STATE_*.
1761	 */
1762	enum sctp_state state;
1763
1764	/* Overall     : The overall association error count.
1765	 * Error Count : [Clear this any time I get something.]
1766	 */
1767	int overall_error_count;
1768
1769	/* The cookie life I award for any cookie.  */
1770	ktime_t cookie_life;
1771
1772	/* These are the association's initial, max, and min RTO values.
1773	 * These values will be initialized by system defaults, but can
1774	 * be modified via the SCTP_RTOINFO socket option.
1775	 */
1776	unsigned long rto_initial;
1777	unsigned long rto_max;
1778	unsigned long rto_min;
1779
1780	/* Maximum number of new data packets that can be sent in a burst.  */
1781	int max_burst;
1782
1783	/* This is the max_retrans value for the association.  This value will
1784	 * be initialized from system defaults, but can be
1785	 * modified by the SCTP_ASSOCINFO socket option.
1786	 */
1787	int max_retrans;
1788
1789	/* This is the partially failed retrans value for the transport
1790	 * and will be initialized from the assocs value.  This can be
1791	 * changed using the SCTP_PEER_ADDR_THLDS socket option
1792	 */
1793	__u16 pf_retrans;
1794	/* Used for primary path switchover. */
1795	__u16 ps_retrans;
1796
1797	/* Maximum number of times the endpoint will retransmit INIT  */
1798	__u16 max_init_attempts;
1799
1800	/* How many times have we resent an INIT? */
1801	__u16 init_retries;
1802
1803	/* The largest timeout or RTO value to use in attempting an INIT */
1804	unsigned long max_init_timeo;
1805
1806	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1807	 * the destination address every heartbeat interval. This value
1808	 * will be inherited by all new transports.
1809	 */
1810	unsigned long hbinterval;
1811	unsigned long probe_interval;
1812
1813	__be16 encap_port;
1814
1815	/* This is the max_retrans value for new transports in the
1816	 * association.
1817	 */
1818	__u16 pathmaxrxt;
1819
1820	__u32 flowlabel;
1821	__u8  dscp;
1822
1823	/* Flag that path mtu update is pending */
1824	__u8   pmtu_pending;
1825
1826	/* Association : The smallest PMTU discovered for all of the
1827	 * PMTU	       : peer's transport addresses.
1828	 */
1829	__u32 pathmtu;
1830
1831	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1832	__u32 param_flags;
1833
1834	__u32 sackfreq;
1835	/* SACK delay timeout */
1836	unsigned long sackdelay;
1837
1838	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1839	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1840
1841	/* Transport to which SHUTDOWN chunk was last sent.  */
1842	struct sctp_transport *shutdown_last_sent_to;
1843
1844	/* Transport to which INIT chunk was last sent.  */
1845	struct sctp_transport *init_last_sent_to;
1846
1847	/* How many times have we resent a SHUTDOWN */
1848	int shutdown_retries;
1849
1850	/* Next TSN    : The next TSN number to be assigned to a new
1851	 *	       : DATA chunk.  This is sent in the INIT or INIT
1852	 *	       : ACK chunk to the peer and incremented each
1853	 *	       : time a DATA chunk is assigned a TSN
1854	 *	       : (normally just prior to transmit or during
1855	 *	       : fragmentation).
1856	 */
1857	__u32 next_tsn;
1858
1859	/*
1860	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1861	 * TSN	       : is set initially by taking the peer's Initial TSN,
1862	 *	       : received in the INIT or INIT ACK chunk, and
1863	 *	       : subtracting one from it.
1864	 *
1865	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1866	 */
1867
1868	__u32 ctsn_ack_point;
1869
1870	/* PR-SCTP Advanced.Peer.Ack.Point */
1871	__u32 adv_peer_ack_point;
1872
1873	/* Highest TSN that is acknowledged by incoming SACKs. */
1874	__u32 highest_sacked;
1875
1876	/* TSN marking the fast recovery exit point */
1877	__u32 fast_recovery_exit;
1878
1879	/* Flag to track the current fast recovery state */
1880	__u8 fast_recovery;
1881
1882	/* The number of unacknowledged data chunks.  Reported through
1883	 * the SCTP_STATUS sockopt.
1884	 */
1885	__u16 unack_data;
1886
1887	/* The total number of data chunks that we've had to retransmit
1888	 * as the result of a T3 timer expiration
1889	 */
1890	__u32 rtx_data_chunks;
1891
1892	/* This is the association's receive buffer space.  This value is used
1893	 * to set a_rwnd field in an INIT or a SACK chunk.
1894	 */
1895	__u32 rwnd;
1896
1897	/* This is the last advertised value of rwnd over a SACK chunk. */
1898	__u32 a_rwnd;
1899
1900	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1901	 * to slop over a maximum of the association's frag_point.
1902	 */
1903	__u32 rwnd_over;
1904
1905	/* Keeps treack of rwnd pressure.  This happens when we have
1906	 * a window, but not recevie buffer (i.e small packets).  This one
1907	 * is releases slowly (1 PMTU at a time ).
1908	 */
1909	__u32 rwnd_press;
1910
1911	/* This is the sndbuf size in use for the association.
1912	 * This corresponds to the sndbuf size for the association,
1913	 * as specified in the sk->sndbuf.
1914	 */
1915	int sndbuf_used;
1916
1917	/* This is the amount of memory that this association has allocated
1918	 * in the receive path at any given time.
1919	 */
1920	atomic_t rmem_alloc;
1921
1922	/* This is the wait queue head for send requests waiting on
1923	 * the association sndbuf space.
1924	 */
1925	wait_queue_head_t	wait;
1926
1927	/* The message size at which SCTP fragmentation will occur. */
1928	__u32 frag_point;
1929	__u32 user_frag;
1930
1931	/* Counter used to count INIT errors. */
1932	int init_err_counter;
1933
1934	/* Count the number of INIT cycles (for doubling timeout). */
1935	int init_cycle;
1936
1937	/* Default send parameters. */
1938	__u16 default_stream;
1939	__u16 default_flags;
1940	__u32 default_ppid;
1941	__u32 default_context;
1942	__u32 default_timetolive;
1943
1944	/* Default receive parameters */
1945	__u32 default_rcv_context;
1946
1947	/* Stream arrays */
1948	struct sctp_stream stream;
1949
1950	/* All outbound chunks go through this structure.  */
1951	struct sctp_outq outqueue;
1952
1953	/* A smart pipe that will handle reordering and fragmentation,
1954	 * as well as handle passing events up to the ULP.
1955	 */
1956	struct sctp_ulpq ulpq;
1957
1958	/* Last TSN that caused an ECNE Chunk to be sent.  */
1959	__u32 last_ecne_tsn;
1960
1961	/* Last TSN that caused a CWR Chunk to be sent.	 */
1962	__u32 last_cwr_tsn;
1963
1964	/* How many duplicated TSNs have we seen?  */
1965	int numduptsns;
1966
1967	/* These are to support
1968	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1969	 *  and Enforcement of Flow and Message Limits"
1970	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1971	 * or "ADDIP" for short.
1972	 */
1973
1974
1975
1976	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1977	 *
1978	 * R1) One and only one ASCONF Chunk MAY be in transit and
1979	 * unacknowledged at any one time.  If a sender, after sending
1980	 * an ASCONF chunk, decides it needs to transfer another
1981	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1982	 * returns from the previous ASCONF Chunk before sending a
1983	 * subsequent ASCONF. Note this restriction binds each side,
1984	 * so at any time two ASCONF may be in-transit on any given
1985	 * association (one sent from each endpoint).
1986	 *
1987	 * [This is our one-and-only-one ASCONF in flight.  If we do
1988	 * not have an ASCONF in flight, this is NULL.]
1989	 */
1990	struct sctp_chunk *addip_last_asconf;
1991
1992	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1993	 *
1994	 * This is needed to implement itmes E1 - E4 of the updated
1995	 * spec.  Here is the justification:
1996	 *
1997	 * Since the peer may bundle multiple ASCONF chunks toward us,
1998	 * we now need the ability to cache multiple ACKs.  The section
1999	 * describes in detail how they are cached and cleaned up.
2000	 */
2001	struct list_head asconf_ack_list;
2002
2003	/* These ASCONF chunks are waiting to be sent.
2004	 *
2005	 * These chunaks can't be pushed to outqueue until receiving
2006	 * ASCONF_ACK for the previous ASCONF indicated by
2007	 * addip_last_asconf, so as to guarantee that only one ASCONF
2008	 * is in flight at any time.
2009	 *
2010	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
2011	 *
2012	 * In defining the ASCONF Chunk transfer procedures, it is
2013	 * essential that these transfers MUST NOT cause congestion
2014	 * within the network.	To achieve this, we place these
2015	 * restrictions on the transfer of ASCONF Chunks:
2016	 *
2017	 * R1) One and only one ASCONF Chunk MAY be in transit and
2018	 * unacknowledged at any one time.  If a sender, after sending
2019	 * an ASCONF chunk, decides it needs to transfer another
2020	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
2021	 * returns from the previous ASCONF Chunk before sending a
2022	 * subsequent ASCONF. Note this restriction binds each side,
2023	 * so at any time two ASCONF may be in-transit on any given
2024	 * association (one sent from each endpoint).
2025	 *
2026	 *
2027	 * [I really think this is EXACTLY the sort of intelligence
2028	 *  which already resides in sctp_outq.	 Please move this
2029	 *  queue and its supporting logic down there.	--piggy]
2030	 */
2031	struct list_head addip_chunk_list;
2032
2033	/* ADDIP Section 4.1 ASCONF Chunk Procedures
2034	 *
2035	 * A2) A serial number should be assigned to the Chunk. The
2036	 * serial number SHOULD be a monotonically increasing
2037	 * number. The serial number SHOULD be initialized at
2038	 * the start of the association to the same value as the
2039	 * Initial TSN and every time a new ASCONF chunk is created
2040	 * it is incremented by one after assigning the serial number
2041	 * to the newly created chunk.
2042	 *
2043	 * ADDIP
2044	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
2045	 *
2046	 * Serial Number : 32 bits (unsigned integer)
2047	 *
2048	 * This value represents a Serial Number for the ASCONF
2049	 * Chunk. The valid range of Serial Number is from 0 to
2050	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
2051	 * after reaching 4294967295.
2052	 */
2053	__u32 addip_serial;
2054	int src_out_of_asoc_ok;
2055	union sctp_addr *asconf_addr_del_pending;
2056	struct sctp_transport *new_transport;
2057
2058	/* SCTP AUTH: list of the endpoint shared keys.  These
2059	 * keys are provided out of band by the user applicaton
2060	 * and can't change during the lifetime of the association
2061	 */
2062	struct list_head endpoint_shared_keys;
2063
2064	/* SCTP AUTH:
2065	 * The current generated assocaition shared key (secret)
2066	 */
2067	struct sctp_auth_bytes *asoc_shared_key;
2068	struct sctp_shared_key *shkey;
2069
2070	/* SCTP AUTH: hmac id of the first peer requested algorithm
2071	 * that we support.
2072	 */
2073	__u16 default_hmac_id;
2074
2075	__u16 active_key_id;
2076
2077	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
2078	     temp:1,		/* Is it a temporary association? */
2079	     pf_expose:2,       /* Expose pf state? */
2080	     force_delay:1;
2081
2082	__u8 strreset_enable;
2083	__u8 strreset_outstanding; /* request param count on the fly */
2084
2085	__u32 strreset_outseq; /* Update after receiving response */
2086	__u32 strreset_inseq; /* Update after receiving request */
2087	__u32 strreset_result[2]; /* save the results of last 2 responses */
2088
2089	struct sctp_chunk *strreset_chunk; /* save request chunk */
2090
2091	struct sctp_priv_assoc_stats stats;
2092
2093	int sent_cnt_removable;
2094
2095	__u16 subscribe;
2096
2097	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2098	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2099
2100	/* Security identifiers from incoming (INIT). These are set by
2101	 * security_sctp_assoc_request(). These will only be used by
2102	 * SCTP TCP type sockets and peeled off connections as they
2103	 * cause a new socket to be generated. security_sctp_sk_clone()
2104	 * will then plug these into the new socket.
2105	 */
2106
2107	u32 secid;
2108	u32 peer_secid;
2109
2110	struct rcu_head rcu;
2111};
2112
2113
2114/* An eyecatcher for determining if we are really looking at an
2115 * association data structure.
2116 */
2117enum {
2118	SCTP_ASSOC_EYECATCHER = 0xa550c123,
2119};
2120
2121/* Recover the outter association structure. */
2122static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2123{
2124	struct sctp_association *asoc;
2125
2126	asoc = container_of(base, struct sctp_association, base);
2127	return asoc;
2128}
2129
2130/* These are function signatures for manipulating associations.	 */
2131
2132
2133struct sctp_association *
2134sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2135		     enum sctp_scope scope, gfp_t gfp);
2136void sctp_association_free(struct sctp_association *);
2137void sctp_association_put(struct sctp_association *);
2138void sctp_association_hold(struct sctp_association *);
2139
2140struct sctp_transport *sctp_assoc_choose_alter_transport(
2141	struct sctp_association *, struct sctp_transport *);
2142void sctp_assoc_update_retran_path(struct sctp_association *);
2143struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2144					  const union sctp_addr *);
2145int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2146			    const union sctp_addr *laddr);
2147struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2148				     const union sctp_addr *address,
2149				     const gfp_t gfp,
2150				     const int peer_state);
2151void sctp_assoc_del_peer(struct sctp_association *asoc,
2152			 const union sctp_addr *addr);
2153void sctp_assoc_rm_peer(struct sctp_association *asoc,
2154			 struct sctp_transport *peer);
2155void sctp_assoc_control_transport(struct sctp_association *asoc,
2156				  struct sctp_transport *transport,
2157				  enum sctp_transport_cmd command,
2158				  sctp_sn_error_t error);
2159struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2160void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2161int sctp_assoc_update(struct sctp_association *old,
2162		      struct sctp_association *new);
2163
2164__u32 sctp_association_get_next_tsn(struct sctp_association *);
2165
2166void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2167void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2168void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2169void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2170void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2171void sctp_assoc_set_primary(struct sctp_association *,
2172			    struct sctp_transport *);
2173void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2174				    struct sctp_transport *);
2175int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2176				     enum sctp_scope scope, gfp_t gfp);
2177int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2178					 struct sctp_cookie*,
2179					 gfp_t gfp);
2180int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2181void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2182struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2183					const struct sctp_association *asoc,
2184					__be32 serial);
2185void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2186
2187int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2188			const union sctp_addr *ss2);
2189struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2190
2191/* A convenience structure to parse out SCTP specific CMSGs. */
2192struct sctp_cmsgs {
2193	struct sctp_initmsg *init;
2194	struct sctp_sndrcvinfo *srinfo;
2195	struct sctp_sndinfo *sinfo;
2196	struct sctp_prinfo *prinfo;
2197	struct sctp_authinfo *authinfo;
2198	struct msghdr *addrs_msg;
2199};
2200
2201/* Structure for tracking memory objects */
2202struct sctp_dbg_objcnt_entry {
2203	char *label;
2204	atomic_t *counter;
2205};
2206
2207#endif /* __sctp_structs_h__ */