root/include/net/sctp/structs.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. sctp_sk
  2. sctp_opt2sk
  3. sctp_chunk_stream_no
  4. sctp_packet_empty
  5. sctp_outq_cork
  6. sctp_gso_headskb
  7. sctp_ep
  8. sctp_datachk_len
  9. sctp_datahdr_len
  10. sctp_ftsnchk_len
  11. sctp_ftsnhdr_len

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* SCTP kernel implementation
   3  * (C) Copyright IBM Corp. 2001, 2004
   4  * Copyright (c) 1999-2000 Cisco, Inc.
   5  * Copyright (c) 1999-2001 Motorola, Inc.
   6  * Copyright (c) 2001 Intel Corp.
   7  *
   8  * This file is part of the SCTP kernel implementation
   9  *
  10  * Please send any bug reports or fixes you make to the
  11  * email addresses:
  12  *    lksctp developers <linux-sctp@vger.kernel.org>
  13  *
  14  * Written or modified by:
  15  *    Randall Stewart       <randall@sctp.chicago.il.us>
  16  *    Ken Morneau           <kmorneau@cisco.com>
  17  *    Qiaobing Xie          <qxie1@email.mot.com>
  18  *    La Monte H.P. Yarroll <piggy@acm.org>
  19  *    Karl Knutson          <karl@athena.chicago.il.us>
  20  *    Jon Grimm             <jgrimm@us.ibm.com>
  21  *    Xingang Guo           <xingang.guo@intel.com>
  22  *    Hui Huang             <hui.huang@nokia.com>
  23  *    Sridhar Samudrala     <sri@us.ibm.com>
  24  *    Daisy Chang           <daisyc@us.ibm.com>
  25  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
  26  *    Ardelle Fan           <ardelle.fan@intel.com>
  27  *    Ryan Layer            <rmlayer@us.ibm.com>
  28  *    Anup Pemmaiah         <pemmaiah@cc.usu.edu>
  29  *    Kevin Gao             <kevin.gao@intel.com>
  30  */
  31 
  32 #ifndef __sctp_structs_h__
  33 #define __sctp_structs_h__
  34 
  35 #include <linux/ktime.h>
  36 #include <linux/generic-radix-tree.h>
  37 #include <linux/rhashtable-types.h>
  38 #include <linux/socket.h>       /* linux/in.h needs this!!    */
  39 #include <linux/in.h>           /* We get struct sockaddr_in. */
  40 #include <linux/in6.h>          /* We get struct in6_addr     */
  41 #include <linux/ipv6.h>
  42 #include <asm/param.h>          /* We get MAXHOSTNAMELEN.     */
  43 #include <linux/atomic.h>               /* This gets us atomic counters.  */
  44 #include <linux/skbuff.h>       /* We need sk_buff_head. */
  45 #include <linux/workqueue.h>    /* We need tq_struct.    */
  46 #include <linux/sctp.h>         /* We need sctp* header structs.  */
  47 #include <net/sctp/auth.h>      /* We need auth specific structs */
  48 #include <net/ip.h>             /* For inet_skb_parm */
  49 
  50 /* A convenience structure for handling sockaddr structures.
  51  * We should wean ourselves off this.
  52  */
  53 union sctp_addr {
  54         struct sockaddr_in v4;
  55         struct sockaddr_in6 v6;
  56         struct sockaddr sa;
  57 };
  58 
  59 /* Forward declarations for data structures. */
  60 struct sctp_globals;
  61 struct sctp_endpoint;
  62 struct sctp_association;
  63 struct sctp_transport;
  64 struct sctp_packet;
  65 struct sctp_chunk;
  66 struct sctp_inq;
  67 struct sctp_outq;
  68 struct sctp_bind_addr;
  69 struct sctp_ulpq;
  70 struct sctp_ep_common;
  71 struct crypto_shash;
  72 struct sctp_stream;
  73 
  74 
  75 #include <net/sctp/tsnmap.h>
  76 #include <net/sctp/ulpevent.h>
  77 #include <net/sctp/ulpqueue.h>
  78 #include <net/sctp/stream_interleave.h>
  79 
  80 /* Structures useful for managing bind/connect. */
  81 
  82 struct sctp_bind_bucket {
  83         unsigned short  port;
  84         signed char     fastreuse;
  85         signed char     fastreuseport;
  86         kuid_t          fastuid;
  87         struct hlist_node       node;
  88         struct hlist_head       owner;
  89         struct net      *net;
  90 };
  91 
  92 struct sctp_bind_hashbucket {
  93         spinlock_t      lock;
  94         struct hlist_head       chain;
  95 };
  96 
  97 /* Used for hashing all associations.  */
  98 struct sctp_hashbucket {
  99         rwlock_t        lock;
 100         struct hlist_head       chain;
 101 } __attribute__((__aligned__(8)));
 102 
 103 
 104 /* The SCTP globals structure. */
 105 extern struct sctp_globals {
 106         /* This is a list of groups of functions for each address
 107          * family that we support.
 108          */
 109         struct list_head address_families;
 110 
 111         /* This is the hash of all endpoints. */
 112         struct sctp_hashbucket *ep_hashtable;
 113         /* This is the sctp port control hash.  */
 114         struct sctp_bind_hashbucket *port_hashtable;
 115         /* This is the hash of all transports. */
 116         struct rhltable transport_hashtable;
 117 
 118         /* Sizes of above hashtables. */
 119         int ep_hashsize;
 120         int port_hashsize;
 121 
 122         /* Default initialization values to be applied to new associations. */
 123         __u16 max_instreams;
 124         __u16 max_outstreams;
 125 
 126         /* Flag to indicate whether computing and verifying checksum
 127          * is disabled. */
 128         bool checksum_disable;
 129 } sctp_globals;
 130 
 131 #define sctp_max_instreams              (sctp_globals.max_instreams)
 132 #define sctp_max_outstreams             (sctp_globals.max_outstreams)
 133 #define sctp_address_families           (sctp_globals.address_families)
 134 #define sctp_ep_hashsize                (sctp_globals.ep_hashsize)
 135 #define sctp_ep_hashtable               (sctp_globals.ep_hashtable)
 136 #define sctp_port_hashsize              (sctp_globals.port_hashsize)
 137 #define sctp_port_hashtable             (sctp_globals.port_hashtable)
 138 #define sctp_transport_hashtable        (sctp_globals.transport_hashtable)
 139 #define sctp_checksum_disable           (sctp_globals.checksum_disable)
 140 
 141 /* SCTP Socket type: UDP or TCP style. */
 142 enum sctp_socket_type {
 143         SCTP_SOCKET_UDP = 0,
 144         SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
 145         SCTP_SOCKET_TCP
 146 };
 147 
 148 /* Per socket SCTP information. */
 149 struct sctp_sock {
 150         /* inet_sock has to be the first member of sctp_sock */
 151         struct inet_sock inet;
 152         /* What kind of a socket is this? */
 153         enum sctp_socket_type type;
 154 
 155         /* PF_ family specific functions.  */
 156         struct sctp_pf *pf;
 157 
 158         /* Access to HMAC transform. */
 159         struct crypto_shash *hmac;
 160         char *sctp_hmac_alg;
 161 
 162         /* What is our base endpointer? */
 163         struct sctp_endpoint *ep;
 164 
 165         struct sctp_bind_bucket *bind_hash;
 166         /* Various Socket Options.  */
 167         __u16 default_stream;
 168         __u32 default_ppid;
 169         __u16 default_flags;
 170         __u32 default_context;
 171         __u32 default_timetolive;
 172         __u32 default_rcv_context;
 173         int max_burst;
 174 
 175         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
 176          * the destination address every heartbeat interval. This value
 177          * will be inherited by all new associations.
 178          */
 179         __u32 hbinterval;
 180 
 181         /* This is the max_retrans value for new associations. */
 182         __u16 pathmaxrxt;
 183 
 184         __u32 flowlabel;
 185         __u8  dscp;
 186 
 187         int pf_retrans;
 188 
 189         /* The initial Path MTU to use for new associations. */
 190         __u32 pathmtu;
 191 
 192         /* The default SACK delay timeout for new associations. */
 193         __u32 sackdelay;
 194         __u32 sackfreq;
 195 
 196         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
 197         __u32 param_flags;
 198 
 199         __u32 default_ss;
 200 
 201         struct sctp_rtoinfo rtoinfo;
 202         struct sctp_paddrparams paddrparam;
 203         struct sctp_assocparams assocparams;
 204 
 205         /*
 206          * These two structures must be grouped together for the usercopy
 207          * whitelist region.
 208          */
 209         __u16 subscribe;
 210         struct sctp_initmsg initmsg;
 211 
 212         int user_frag;
 213 
 214         __u32 autoclose;
 215         __u32 adaptation_ind;
 216         __u32 pd_point;
 217         __u16   nodelay:1,
 218                 reuse:1,
 219                 disable_fragments:1,
 220                 v4mapped:1,
 221                 frag_interleave:1,
 222                 recvrcvinfo:1,
 223                 recvnxtinfo:1,
 224                 data_ready_signalled:1;
 225 
 226         atomic_t pd_mode;
 227         /* Receive to here while partial delivery is in effect. */
 228         struct sk_buff_head pd_lobby;
 229 
 230         /* These must be the last fields, as they will skipped on copies,
 231          * like on accept and peeloff operations
 232          */
 233         struct list_head auto_asconf_list;
 234         int do_auto_asconf;
 235 };
 236 
 237 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
 238 {
 239        return (struct sctp_sock *)sk;
 240 }
 241 
 242 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
 243 {
 244        return (struct sock *)sp;
 245 }
 246 
 247 #if IS_ENABLED(CONFIG_IPV6)
 248 struct sctp6_sock {
 249        struct sctp_sock  sctp;
 250        struct ipv6_pinfo inet6;
 251 };
 252 #endif /* CONFIG_IPV6 */
 253 
 254 
 255 /* This is our APPLICATION-SPECIFIC state cookie.
 256  * THIS IS NOT DICTATED BY THE SPECIFICATION.
 257  */
 258 /* These are the parts of an association which we send in the cookie.
 259  * Most of these are straight out of:
 260  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
 261  *
 262  */
 263 
 264 struct sctp_cookie {
 265 
 266         /* My          : Tag expected in every inbound packet and sent
 267          * Verification: in the INIT or INIT ACK chunk.
 268          * Tag         :
 269          */
 270         __u32 my_vtag;
 271 
 272         /* Peer's      : Tag expected in every outbound packet except
 273          * Verification: in the INIT chunk.
 274          * Tag         :
 275          */
 276         __u32 peer_vtag;
 277 
 278         /* The rest of these are not from the spec, but really need to
 279          * be in the cookie.
 280          */
 281 
 282         /* My Tie Tag  : Assist in discovering a restarting association. */
 283         __u32 my_ttag;
 284 
 285         /* Peer's Tie Tag: Assist in discovering a restarting association. */
 286         __u32 peer_ttag;
 287 
 288         /* When does this cookie expire? */
 289         ktime_t expiration;
 290 
 291         /* Number of inbound/outbound streams which are set
 292          * and negotiated during the INIT process.
 293          */
 294         __u16 sinit_num_ostreams;
 295         __u16 sinit_max_instreams;
 296 
 297         /* This is the first sequence number I used.  */
 298         __u32 initial_tsn;
 299 
 300         /* This holds the originating address of the INIT packet.  */
 301         union sctp_addr peer_addr;
 302 
 303         /* IG Section 2.35.3 
 304          * Include the source port of the INIT-ACK
 305          */
 306         __u16           my_port;
 307 
 308         __u8 prsctp_capable;
 309 
 310         /* Padding for future use */
 311         __u8 padding;           
 312 
 313         __u32 adaptation_ind;
 314 
 315         __u8 auth_random[sizeof(struct sctp_paramhdr) +
 316                          SCTP_AUTH_RANDOM_LENGTH];
 317         __u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
 318         __u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
 319 
 320         /* This is a shim for my peer's INIT packet, followed by
 321          * a copy of the raw address list of the association.
 322          * The length of the raw address list is saved in the
 323          * raw_addr_list_len field, which will be used at the time when
 324          * the association TCB is re-constructed from the cookie.
 325          */
 326         __u32 raw_addr_list_len;
 327         struct sctp_init_chunk peer_init[0];
 328 };
 329 
 330 
 331 /* The format of our cookie that we send to our peer. */
 332 struct sctp_signed_cookie {
 333         __u8 signature[SCTP_SECRET_SIZE];
 334         __u32 __pad;            /* force sctp_cookie alignment to 64 bits */
 335         struct sctp_cookie c;
 336 } __packed;
 337 
 338 /* This is another convenience type to allocate memory for address
 339  * params for the maximum size and pass such structures around
 340  * internally.
 341  */
 342 union sctp_addr_param {
 343         struct sctp_paramhdr p;
 344         struct sctp_ipv4addr_param v4;
 345         struct sctp_ipv6addr_param v6;
 346 };
 347 
 348 /* A convenience type to allow walking through the various
 349  * parameters and avoid casting all over the place.
 350  */
 351 union sctp_params {
 352         void *v;
 353         struct sctp_paramhdr *p;
 354         struct sctp_cookie_preserve_param *life;
 355         struct sctp_hostname_param *dns;
 356         struct sctp_cookie_param *cookie;
 357         struct sctp_supported_addrs_param *sat;
 358         struct sctp_ipv4addr_param *v4;
 359         struct sctp_ipv6addr_param *v6;
 360         union sctp_addr_param *addr;
 361         struct sctp_adaptation_ind_param *aind;
 362         struct sctp_supported_ext_param *ext;
 363         struct sctp_random_param *random;
 364         struct sctp_chunks_param *chunks;
 365         struct sctp_hmac_algo_param *hmac_algo;
 366         struct sctp_addip_param *addip;
 367 };
 368 
 369 /* RFC 2960.  Section 3.3.5 Heartbeat.
 370  *    Heartbeat Information: variable length
 371  *    The Sender-specific Heartbeat Info field should normally include
 372  *    information about the sender's current time when this HEARTBEAT
 373  *    chunk is sent and the destination transport address to which this
 374  *    HEARTBEAT is sent (see Section 8.3).
 375  */
 376 struct sctp_sender_hb_info {
 377         struct sctp_paramhdr param_hdr;
 378         union sctp_addr daddr;
 379         unsigned long sent_at;
 380         __u64 hb_nonce;
 381 };
 382 
 383 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
 384                      gfp_t gfp);
 385 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
 386 void sctp_stream_free(struct sctp_stream *stream);
 387 void sctp_stream_clear(struct sctp_stream *stream);
 388 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
 389 
 390 /* What is the current SSN number for this stream? */
 391 #define sctp_ssn_peek(stream, type, sid) \
 392         (sctp_stream_##type((stream), (sid))->ssn)
 393 
 394 /* Return the next SSN number for this stream.  */
 395 #define sctp_ssn_next(stream, type, sid) \
 396         (sctp_stream_##type((stream), (sid))->ssn++)
 397 
 398 /* Skip over this ssn and all below. */
 399 #define sctp_ssn_skip(stream, type, sid, ssn) \
 400         (sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
 401 
 402 /* What is the current MID number for this stream? */
 403 #define sctp_mid_peek(stream, type, sid) \
 404         (sctp_stream_##type((stream), (sid))->mid)
 405 
 406 /* Return the next MID number for this stream.  */
 407 #define sctp_mid_next(stream, type, sid) \
 408         (sctp_stream_##type((stream), (sid))->mid++)
 409 
 410 /* Skip over this mid and all below. */
 411 #define sctp_mid_skip(stream, type, sid, mid) \
 412         (sctp_stream_##type((stream), (sid))->mid = mid + 1)
 413 
 414 /* What is the current MID_uo number for this stream? */
 415 #define sctp_mid_uo_peek(stream, type, sid) \
 416         (sctp_stream_##type((stream), (sid))->mid_uo)
 417 
 418 /* Return the next MID_uo number for this stream.  */
 419 #define sctp_mid_uo_next(stream, type, sid) \
 420         (sctp_stream_##type((stream), (sid))->mid_uo++)
 421 
 422 /*
 423  * Pointers to address related SCTP functions.
 424  * (i.e. things that depend on the address family.)
 425  */
 426 struct sctp_af {
 427         int             (*sctp_xmit)    (struct sk_buff *skb,
 428                                          struct sctp_transport *);
 429         int             (*setsockopt)   (struct sock *sk,
 430                                          int level,
 431                                          int optname,
 432                                          char __user *optval,
 433                                          unsigned int optlen);
 434         int             (*getsockopt)   (struct sock *sk,
 435                                          int level,
 436                                          int optname,
 437                                          char __user *optval,
 438                                          int __user *optlen);
 439         int             (*compat_setsockopt)    (struct sock *sk,
 440                                          int level,
 441                                          int optname,
 442                                          char __user *optval,
 443                                          unsigned int optlen);
 444         int             (*compat_getsockopt)    (struct sock *sk,
 445                                          int level,
 446                                          int optname,
 447                                          char __user *optval,
 448                                          int __user *optlen);
 449         void            (*get_dst)      (struct sctp_transport *t,
 450                                          union sctp_addr *saddr,
 451                                          struct flowi *fl,
 452                                          struct sock *sk);
 453         void            (*get_saddr)    (struct sctp_sock *sk,
 454                                          struct sctp_transport *t,
 455                                          struct flowi *fl);
 456         void            (*copy_addrlist) (struct list_head *,
 457                                           struct net_device *);
 458         int             (*cmp_addr)     (const union sctp_addr *addr1,
 459                                          const union sctp_addr *addr2);
 460         void            (*addr_copy)    (union sctp_addr *dst,
 461                                          union sctp_addr *src);
 462         void            (*from_skb)     (union sctp_addr *,
 463                                          struct sk_buff *skb,
 464                                          int saddr);
 465         void            (*from_sk)      (union sctp_addr *,
 466                                          struct sock *sk);
 467         void            (*from_addr_param) (union sctp_addr *,
 468                                             union sctp_addr_param *,
 469                                             __be16 port, int iif);
 470         int             (*to_addr_param) (const union sctp_addr *,
 471                                           union sctp_addr_param *); 
 472         int             (*addr_valid)   (union sctp_addr *,
 473                                          struct sctp_sock *,
 474                                          const struct sk_buff *);
 475         enum sctp_scope (*scope)(union sctp_addr *);
 476         void            (*inaddr_any)   (union sctp_addr *, __be16);
 477         int             (*is_any)       (const union sctp_addr *);
 478         int             (*available)    (union sctp_addr *,
 479                                          struct sctp_sock *);
 480         int             (*skb_iif)      (const struct sk_buff *sk);
 481         int             (*is_ce)        (const struct sk_buff *sk);
 482         void            (*seq_dump_addr)(struct seq_file *seq,
 483                                          union sctp_addr *addr);
 484         void            (*ecn_capable)(struct sock *sk);
 485         __u16           net_header_len;
 486         int             sockaddr_len;
 487         int             (*ip_options_len)(struct sock *sk);
 488         sa_family_t     sa_family;
 489         struct list_head list;
 490 };
 491 
 492 struct sctp_af *sctp_get_af_specific(sa_family_t);
 493 int sctp_register_af(struct sctp_af *);
 494 
 495 /* Protocol family functions. */
 496 struct sctp_pf {
 497         void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
 498         void (*skb_msgname)  (struct sk_buff *, char *, int *);
 499         int  (*af_supported) (sa_family_t, struct sctp_sock *);
 500         int  (*cmp_addr) (const union sctp_addr *,
 501                           const union sctp_addr *,
 502                           struct sctp_sock *);
 503         int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
 504         int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
 505         int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
 506         struct sock *(*create_accept_sk) (struct sock *sk,
 507                                           struct sctp_association *asoc,
 508                                           bool kern);
 509         int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
 510         void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
 511         void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
 512         void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
 513         struct sctp_af *af;
 514 };
 515 
 516 
 517 /* Structure to track chunk fragments that have been acked, but peer
 518  * fragments of the same message have not.
 519  */
 520 struct sctp_datamsg {
 521         /* Chunks waiting to be submitted to lower layer. */
 522         struct list_head chunks;
 523         /* Reference counting. */
 524         refcount_t refcnt;
 525         /* When is this message no longer interesting to the peer? */
 526         unsigned long expires_at;
 527         /* Did the messenge fail to send? */
 528         int send_error;
 529         u8 send_failed:1,
 530            can_delay:1, /* should this message be Nagle delayed */
 531            abandoned:1; /* should this message be abandoned */
 532 };
 533 
 534 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
 535                                             struct sctp_sndrcvinfo *,
 536                                             struct iov_iter *);
 537 void sctp_datamsg_free(struct sctp_datamsg *);
 538 void sctp_datamsg_put(struct sctp_datamsg *);
 539 void sctp_chunk_fail(struct sctp_chunk *, int error);
 540 int sctp_chunk_abandoned(struct sctp_chunk *);
 541 
 542 /* RFC2960 1.4 Key Terms
 543  *
 544  * o Chunk: A unit of information within an SCTP packet, consisting of
 545  * a chunk header and chunk-specific content.
 546  *
 547  * As a matter of convenience, we remember the SCTP common header for
 548  * each chunk as well as a few other header pointers...
 549  */
 550 struct sctp_chunk {
 551         struct list_head list;
 552 
 553         refcount_t refcnt;
 554 
 555         /* How many times this chunk have been sent, for prsctp RTX policy */
 556         int sent_count;
 557 
 558         union {
 559                 /* This is our link to the per-transport transmitted list.  */
 560                 struct list_head transmitted_list;
 561                 /* List in specific stream outq */
 562                 struct list_head stream_list;
 563         };
 564 
 565         /* This field is used by chunks that hold fragmented data.
 566          * For the first fragment this is the list that holds the rest of
 567          * fragments. For the remaining fragments, this is the link to the
 568          * frag_list maintained in the first fragment.
 569          */
 570         struct list_head frag_list;
 571 
 572         /* This points to the sk_buff containing the actual data.  */
 573         struct sk_buff *skb;
 574 
 575         union {
 576                 /* In case of GSO packets, this will store the head one */
 577                 struct sk_buff *head_skb;
 578                 /* In case of auth enabled, this will point to the shkey */
 579                 struct sctp_shared_key *shkey;
 580         };
 581 
 582         /* These are the SCTP headers by reverse order in a packet.
 583          * Note that some of these may happen more than once.  In that
 584          * case, we point at the "current" one, whatever that means
 585          * for that level of header.
 586          */
 587 
 588         /* We point this at the FIRST TLV parameter to chunk_hdr.  */
 589         union sctp_params param_hdr;
 590         union {
 591                 __u8 *v;
 592                 struct sctp_datahdr *data_hdr;
 593                 struct sctp_inithdr *init_hdr;
 594                 struct sctp_sackhdr *sack_hdr;
 595                 struct sctp_heartbeathdr *hb_hdr;
 596                 struct sctp_sender_hb_info *hbs_hdr;
 597                 struct sctp_shutdownhdr *shutdown_hdr;
 598                 struct sctp_signed_cookie *cookie_hdr;
 599                 struct sctp_ecnehdr *ecne_hdr;
 600                 struct sctp_cwrhdr *ecn_cwr_hdr;
 601                 struct sctp_errhdr *err_hdr;
 602                 struct sctp_addiphdr *addip_hdr;
 603                 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
 604                 struct sctp_authhdr *auth_hdr;
 605                 struct sctp_idatahdr *idata_hdr;
 606                 struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
 607         } subh;
 608 
 609         __u8 *chunk_end;
 610 
 611         struct sctp_chunkhdr *chunk_hdr;
 612         struct sctphdr *sctp_hdr;
 613 
 614         /* This needs to be recoverable for SCTP_SEND_FAILED events. */
 615         struct sctp_sndrcvinfo sinfo;
 616 
 617         /* Which association does this belong to?  */
 618         struct sctp_association *asoc;
 619 
 620         /* What endpoint received this chunk? */
 621         struct sctp_ep_common *rcvr;
 622 
 623         /* We fill this in if we are calculating RTT. */
 624         unsigned long sent_at;
 625 
 626         /* What is the origin IP address for this chunk?  */
 627         union sctp_addr source;
 628         /* Destination address for this chunk. */
 629         union sctp_addr dest;
 630 
 631         /* For outbound message, track all fragments for SEND_FAILED. */
 632         struct sctp_datamsg *msg;
 633 
 634         /* For an inbound chunk, this tells us where it came from.
 635          * For an outbound chunk, it tells us where we'd like it to
 636          * go.  It is NULL if we have no preference.
 637          */
 638         struct sctp_transport *transport;
 639 
 640         /* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
 641          * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
 642          * spec violates the principle premis that all chunks are processed
 643          * in order.
 644          */
 645         struct sk_buff *auth_chunk;
 646 
 647 #define SCTP_CAN_FRTX 0x0
 648 #define SCTP_NEED_FRTX 0x1
 649 #define SCTP_DONT_FRTX 0x2
 650         __u16   rtt_in_progress:1,      /* This chunk used for RTT calc? */
 651                 has_tsn:1,              /* Does this chunk have a TSN yet? */
 652                 has_ssn:1,              /* Does this chunk have a SSN yet? */
 653 #define has_mid has_ssn
 654                 singleton:1,            /* Only chunk in the packet? */
 655                 end_of_packet:1,        /* Last chunk in the packet? */
 656                 ecn_ce_done:1,          /* Have we processed the ECN CE bit? */
 657                 pdiscard:1,             /* Discard the whole packet now? */
 658                 tsn_gap_acked:1,        /* Is this chunk acked by a GAP ACK? */
 659                 data_accepted:1,        /* At least 1 chunk accepted */
 660                 auth:1,                 /* IN: was auth'ed | OUT: needs auth */
 661                 has_asconf:1,           /* IN: have seen an asconf before */
 662                 tsn_missing_report:2,   /* Data chunk missing counter. */
 663                 fast_retransmit:2;      /* Is this chunk fast retransmitted? */
 664 };
 665 
 666 #define sctp_chunk_retransmitted(chunk) (chunk->sent_count > 1)
 667 void sctp_chunk_hold(struct sctp_chunk *);
 668 void sctp_chunk_put(struct sctp_chunk *);
 669 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
 670                           struct iov_iter *from);
 671 void sctp_chunk_free(struct sctp_chunk *);
 672 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
 673 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
 674                                  const struct sctp_association *,
 675                                  struct sock *, gfp_t gfp);
 676 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
 677                      union sctp_addr *);
 678 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
 679 
 680 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
 681 {
 682         return ntohs(ch->subh.data_hdr->stream);
 683 }
 684 
 685 enum {
 686         SCTP_ADDR_NEW,          /* new address added to assoc/ep */
 687         SCTP_ADDR_SRC,          /* address can be used as source */
 688         SCTP_ADDR_DEL,          /* address about to be deleted */
 689 };
 690 
 691 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
 692 struct sctp_sockaddr_entry {
 693         struct list_head list;
 694         struct rcu_head rcu;
 695         union sctp_addr a;
 696         __u8 state;
 697         __u8 valid;
 698 };
 699 
 700 #define SCTP_ADDRESS_TICK_DELAY 500
 701 
 702 /* This structure holds lists of chunks as we are assembling for
 703  * transmission.
 704  */
 705 struct sctp_packet {
 706         /* These are the SCTP header values (host order) for the packet. */
 707         __u16 source_port;
 708         __u16 destination_port;
 709         __u32 vtag;
 710 
 711         /* This contains the payload chunks.  */
 712         struct list_head chunk_list;
 713 
 714         /* This is the overhead of the sctp and ip headers. */
 715         size_t overhead;
 716         /* This is the total size of all chunks INCLUDING padding.  */
 717         size_t size;
 718         /* This is the maximum size this packet may have */
 719         size_t max_size;
 720 
 721         /* The packet is destined for this transport address.
 722          * The function we finally use to pass down to the next lower
 723          * layer lives in the transport structure.
 724          */
 725         struct sctp_transport *transport;
 726 
 727         /* pointer to the auth chunk for this packet */
 728         struct sctp_chunk *auth;
 729 
 730         u8  has_cookie_echo:1,  /* This packet contains a COOKIE-ECHO chunk. */
 731             has_sack:1,         /* This packet contains a SACK chunk. */
 732             has_auth:1,         /* This packet contains an AUTH chunk */
 733             has_data:1,         /* This packet contains at least 1 DATA chunk */
 734             ipfragok:1;         /* So let ip fragment this packet */
 735 };
 736 
 737 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
 738                       __u16 sport, __u16 dport);
 739 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
 740 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
 741                                           struct sctp_chunk *chunk,
 742                                           int one_packet, gfp_t gfp);
 743 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
 744                                         struct sctp_chunk *chunk);
 745 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
 746 void sctp_packet_free(struct sctp_packet *);
 747 
 748 static inline int sctp_packet_empty(struct sctp_packet *packet)
 749 {
 750         return packet->size == packet->overhead;
 751 }
 752 
 753 /* This represents a remote transport address.
 754  * For local transport addresses, we just use union sctp_addr.
 755  *
 756  * RFC2960 Section 1.4 Key Terms
 757  *
 758  *   o  Transport address:  A Transport Address is traditionally defined
 759  *      by Network Layer address, Transport Layer protocol and Transport
 760  *      Layer port number.  In the case of SCTP running over IP, a
 761  *      transport address is defined by the combination of an IP address
 762  *      and an SCTP port number (where SCTP is the Transport protocol).
 763  *
 764  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
 765  *
 766  *   o  The sender keeps a separate congestion control parameter set for
 767  *      each of the destination addresses it can send to (not each
 768  *      source-destination pair but for each destination).  The parameters
 769  *      should decay if the address is not used for a long enough time
 770  *      period.
 771  *
 772  */
 773 struct sctp_transport {
 774         /* A list of transports. */
 775         struct list_head transports;
 776         struct rhlist_head node;
 777 
 778         /* Reference counting. */
 779         refcount_t refcnt;
 780                 /* RTO-Pending : A flag used to track if one of the DATA
 781                  *              chunks sent to this address is currently being
 782                  *              used to compute a RTT. If this flag is 0,
 783                  *              the next DATA chunk sent to this destination
 784                  *              should be used to compute a RTT and this flag
 785                  *              should be set. Every time the RTT
 786                  *              calculation completes (i.e. the DATA chunk
 787                  *              is SACK'd) clear this flag.
 788                  */
 789         __u32   rto_pending:1,
 790 
 791                 /*
 792                  * hb_sent : a flag that signals that we have a pending
 793                  * heartbeat.
 794                  */
 795                 hb_sent:1,
 796 
 797                 /* Is the Path MTU update pending on this tranport */
 798                 pmtu_pending:1,
 799 
 800                 dst_pending_confirm:1,  /* need to confirm neighbour */
 801 
 802                 /* Has this transport moved the ctsn since we last sacked */
 803                 sack_generation:1;
 804         u32 dst_cookie;
 805 
 806         struct flowi fl;
 807 
 808         /* This is the peer's IP address and port. */
 809         union sctp_addr ipaddr;
 810 
 811         /* These are the functions we call to handle LLP stuff.  */
 812         struct sctp_af *af_specific;
 813 
 814         /* Which association do we belong to?  */
 815         struct sctp_association *asoc;
 816 
 817         /* RFC2960
 818          *
 819          * 12.3 Per Transport Address Data
 820          *
 821          * For each destination transport address in the peer's
 822          * address list derived from the INIT or INIT ACK chunk, a
 823          * number of data elements needs to be maintained including:
 824          */
 825         /* RTO         : The current retransmission timeout value.  */
 826         unsigned long rto;
 827 
 828         __u32 rtt;              /* This is the most recent RTT.  */
 829 
 830         /* RTTVAR      : The current RTT variation.  */
 831         __u32 rttvar;
 832 
 833         /* SRTT        : The current smoothed round trip time.  */
 834         __u32 srtt;
 835 
 836         /*
 837          * These are the congestion stats.
 838          */
 839         /* cwnd        : The current congestion window.  */
 840         __u32 cwnd;               /* This is the actual cwnd.  */
 841 
 842         /* ssthresh    : The current slow start threshold value.  */
 843         __u32 ssthresh;
 844 
 845         /* partial     : The tracking method for increase of cwnd when in
 846          * bytes acked : congestion avoidance mode (see Section 6.2.2)
 847          */
 848         __u32 partial_bytes_acked;
 849 
 850         /* Data that has been sent, but not acknowledged. */
 851         __u32 flight_size;
 852 
 853         __u32 burst_limited;    /* Holds old cwnd when max.burst is applied */
 854 
 855         /* Destination */
 856         struct dst_entry *dst;
 857         /* Source address. */
 858         union sctp_addr saddr;
 859 
 860         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
 861          * the destination address every heartbeat interval.
 862          */
 863         unsigned long hbinterval;
 864 
 865         /* SACK delay timeout */
 866         unsigned long sackdelay;
 867         __u32 sackfreq;
 868 
 869         atomic_t mtu_info;
 870 
 871         /* When was the last time that we heard from this transport? We use
 872          * this to pick new active and retran paths.
 873          */
 874         ktime_t last_time_heard;
 875 
 876         /* When was the last time that we sent a chunk using this
 877          * transport? We use this to check for idle transports
 878          */
 879         unsigned long last_time_sent;
 880 
 881         /* Last time(in jiffies) when cwnd is reduced due to the congestion
 882          * indication based on ECNE chunk.
 883          */
 884         unsigned long last_time_ecne_reduced;
 885 
 886         /* This is the max_retrans value for the transport and will
 887          * be initialized from the assocs value.  This can be changed
 888          * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
 889          */
 890         __u16 pathmaxrxt;
 891 
 892         __u32 flowlabel;
 893         __u8  dscp;
 894 
 895         /* This is the partially failed retrans value for the transport
 896          * and will be initialized from the assocs value.  This can be changed
 897          * using the SCTP_PEER_ADDR_THLDS socket option
 898          */
 899         int pf_retrans;
 900         /* PMTU       : The current known path MTU.  */
 901         __u32 pathmtu;
 902 
 903         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
 904         __u32 param_flags;
 905 
 906         /* The number of times INIT has been sent on this transport. */
 907         int init_sent_count;
 908 
 909         /* state       : The current state of this destination,
 910          *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
 911          */
 912         int state;
 913 
 914         /* These are the error stats for this destination.  */
 915 
 916         /* Error count : The current error count for this destination.  */
 917         unsigned short error_count;
 918 
 919         /* Per         : A timer used by each destination.
 920          * Destination :
 921          * Timer       :
 922          *
 923          * [Everywhere else in the text this is called T3-rtx. -ed]
 924          */
 925         struct timer_list T3_rtx_timer;
 926 
 927         /* Heartbeat timer is per destination. */
 928         struct timer_list hb_timer;
 929 
 930         /* Timer to handle ICMP proto unreachable envets */
 931         struct timer_list proto_unreach_timer;
 932 
 933         /* Timer to handler reconf chunk rtx */
 934         struct timer_list reconf_timer;
 935 
 936         /* Since we're using per-destination retransmission timers
 937          * (see above), we're also using per-destination "transmitted"
 938          * queues.  This probably ought to be a private struct
 939          * accessible only within the outqueue, but it's not, yet.
 940          */
 941         struct list_head transmitted;
 942 
 943         /* We build bundle-able packets for this transport here.  */
 944         struct sctp_packet packet;
 945 
 946         /* This is the list of transports that have chunks to send.  */
 947         struct list_head send_ready;
 948 
 949         /* State information saved for SFR_CACC algorithm. The key
 950          * idea in SFR_CACC is to maintain state at the sender on a
 951          * per-destination basis when a changeover happens.
 952          *      char changeover_active;
 953          *      char cycling_changeover;
 954          *      __u32 next_tsn_at_change;
 955          *      char cacc_saw_newack;
 956          */
 957         struct {
 958                 /* An unsigned integer, which stores the next TSN to be
 959                  * used by the sender, at the moment of changeover.
 960                  */
 961                 __u32 next_tsn_at_change;
 962 
 963                 /* A flag which indicates the occurrence of a changeover */
 964                 char changeover_active;
 965 
 966                 /* A flag which indicates whether the change of primary is
 967                  * the first switch to this destination address during an
 968                  * active switch.
 969                  */
 970                 char cycling_changeover;
 971 
 972                 /* A temporary flag, which is used during the processing of
 973                  * a SACK to estimate the causative TSN(s)'s group.
 974                  */
 975                 char cacc_saw_newack;
 976         } cacc;
 977 
 978         /* 64-bit random number sent with heartbeat. */
 979         __u64 hb_nonce;
 980 
 981         struct rcu_head rcu;
 982 };
 983 
 984 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
 985                                           gfp_t);
 986 void sctp_transport_set_owner(struct sctp_transport *,
 987                               struct sctp_association *);
 988 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
 989                           struct sctp_sock *);
 990 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
 991 void sctp_transport_free(struct sctp_transport *);
 992 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
 993 void sctp_transport_reset_hb_timer(struct sctp_transport *);
 994 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
 995 int sctp_transport_hold(struct sctp_transport *);
 996 void sctp_transport_put(struct sctp_transport *);
 997 void sctp_transport_update_rto(struct sctp_transport *, __u32);
 998 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
 999 void sctp_transport_lower_cwnd(struct sctp_transport *t,
1000                                enum sctp_lower_cwnd reason);
1001 void sctp_transport_burst_limited(struct sctp_transport *);
1002 void sctp_transport_burst_reset(struct sctp_transport *);
1003 unsigned long sctp_transport_timeout(struct sctp_transport *);
1004 void sctp_transport_reset(struct sctp_transport *t);
1005 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1006 void sctp_transport_immediate_rtx(struct sctp_transport *);
1007 void sctp_transport_dst_release(struct sctp_transport *t);
1008 void sctp_transport_dst_confirm(struct sctp_transport *t);
1009 
1010 
1011 /* This is the structure we use to queue packets as they come into
1012  * SCTP.  We write packets to it and read chunks from it.
1013  */
1014 struct sctp_inq {
1015         /* This is actually a queue of sctp_chunk each
1016          * containing a partially decoded packet.
1017          */
1018         struct list_head in_chunk_list;
1019         /* This is the packet which is currently off the in queue and is
1020          * being worked on through the inbound chunk processing.
1021          */
1022         struct sctp_chunk *in_progress;
1023 
1024         /* This is the delayed task to finish delivering inbound
1025          * messages.
1026          */
1027         struct work_struct immediate;
1028 };
1029 
1030 void sctp_inq_init(struct sctp_inq *);
1031 void sctp_inq_free(struct sctp_inq *);
1032 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1033 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1034 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1035 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1036 
1037 /* This is the structure we use to hold outbound chunks.  You push
1038  * chunks in and they automatically pop out the other end as bundled
1039  * packets (it calls (*output_handler)()).
1040  *
1041  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1042  * and 8.2 of the v13 draft.
1043  *
1044  * It handles retransmissions.  The connection to the timeout portion
1045  * of the state machine is through sctp_..._timeout() and timeout_handler.
1046  *
1047  * If you feed it SACKs, it will eat them.
1048  *
1049  * If you give it big chunks, it will fragment them.
1050  *
1051  * It assigns TSN's to data chunks.  This happens at the last possible
1052  * instant before transmission.
1053  *
1054  * When free()'d, it empties itself out via output_handler().
1055  */
1056 struct sctp_outq {
1057         struct sctp_association *asoc;
1058 
1059         /* Data pending that has never been transmitted.  */
1060         struct list_head out_chunk_list;
1061 
1062         /* Stream scheduler being used */
1063         struct sctp_sched_ops *sched;
1064 
1065         unsigned int out_qlen;  /* Total length of queued data chunks. */
1066 
1067         /* Error of send failed, may used in SCTP_SEND_FAILED event. */
1068         unsigned int error;
1069 
1070         /* These are control chunks we want to send.  */
1071         struct list_head control_chunk_list;
1072 
1073         /* These are chunks that have been sacked but are above the
1074          * CTSN, or cumulative tsn ack point.
1075          */
1076         struct list_head sacked;
1077 
1078         /* Put chunks on this list to schedule them for
1079          * retransmission.
1080          */
1081         struct list_head retransmit;
1082 
1083         /* Put chunks on this list to save them for FWD TSN processing as
1084          * they were abandoned.
1085          */
1086         struct list_head abandoned;
1087 
1088         /* How many unackd bytes do we have in-flight?  */
1089         __u32 outstanding_bytes;
1090 
1091         /* Are we doing fast-rtx on this queue */
1092         char fast_rtx;
1093 
1094         /* Corked? */
1095         char cork;
1096 };
1097 
1098 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1099 void sctp_outq_teardown(struct sctp_outq *);
1100 void sctp_outq_free(struct sctp_outq*);
1101 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1102 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1103 int sctp_outq_is_empty(const struct sctp_outq *);
1104 void sctp_outq_restart(struct sctp_outq *);
1105 
1106 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1107                      enum sctp_retransmit_reason reason);
1108 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1109 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1110 void sctp_prsctp_prune(struct sctp_association *asoc,
1111                        struct sctp_sndrcvinfo *sinfo, int msg_len);
1112 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1113 /* Uncork and flush an outqueue.  */
1114 static inline void sctp_outq_cork(struct sctp_outq *q)
1115 {
1116         q->cork = 1;
1117 }
1118 
1119 /* SCTP skb control block.
1120  * sctp_input_cb is currently used on rx and sock rx queue
1121  */
1122 struct sctp_input_cb {
1123         union {
1124                 struct inet_skb_parm    h4;
1125 #if IS_ENABLED(CONFIG_IPV6)
1126                 struct inet6_skb_parm   h6;
1127 #endif
1128         } header;
1129         struct sctp_chunk *chunk;
1130         struct sctp_af *af;
1131 };
1132 #define SCTP_INPUT_CB(__skb)    ((struct sctp_input_cb *)&((__skb)->cb[0]))
1133 
1134 struct sctp_output_cb {
1135         struct sk_buff *last;
1136 };
1137 #define SCTP_OUTPUT_CB(__skb)   ((struct sctp_output_cb *)&((__skb)->cb[0]))
1138 
1139 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1140 {
1141         const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1142 
1143         return chunk->head_skb ? : skb;
1144 }
1145 
1146 /* These bind address data fields common between endpoints and associations */
1147 struct sctp_bind_addr {
1148 
1149         /* RFC 2960 12.1 Parameters necessary for the SCTP instance
1150          *
1151          * SCTP Port:   The local SCTP port number the endpoint is
1152          *              bound to.
1153          */
1154         __u16 port;
1155 
1156         /* RFC 2960 12.1 Parameters necessary for the SCTP instance
1157          *
1158          * Address List: The list of IP addresses that this instance
1159          *      has bound.  This information is passed to one's
1160          *      peer(s) in INIT and INIT ACK chunks.
1161          */
1162         struct list_head address_list;
1163 };
1164 
1165 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1166 void sctp_bind_addr_free(struct sctp_bind_addr *);
1167 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1168                         const struct sctp_bind_addr *src,
1169                         enum sctp_scope scope, gfp_t gfp,
1170                         int flags);
1171 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1172                         const struct sctp_bind_addr *src,
1173                         gfp_t gfp);
1174 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1175                        int new_size, __u8 addr_state, gfp_t gfp);
1176 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1177 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1178                          struct sctp_sock *);
1179 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1180                          struct sctp_sock *, struct sctp_sock *);
1181 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1182                          const union sctp_addr *addr);
1183 int sctp_bind_addrs_check(struct sctp_sock *sp,
1184                           struct sctp_sock *sp2, int cnt2);
1185 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr   *bp,
1186                                         const union sctp_addr   *addrs,
1187                                         int                     addrcnt,
1188                                         struct sctp_sock        *opt);
1189 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1190                                          int *addrs_len,
1191                                          gfp_t gfp);
1192 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1193                            __u16 port, gfp_t gfp);
1194 
1195 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1196 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1197                   const enum sctp_scope scope);
1198 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1199 int sctp_is_ep_boundall(struct sock *sk);
1200 
1201 
1202 /* What type of endpoint?  */
1203 enum sctp_endpoint_type {
1204         SCTP_EP_TYPE_SOCKET,
1205         SCTP_EP_TYPE_ASSOCIATION,
1206 };
1207 
1208 /*
1209  * A common base class to bridge the implmentation view of a
1210  * socket (usually listening) endpoint versus an association's
1211  * local endpoint.
1212  * This common structure is useful for several purposes:
1213  *   1) Common interface for lookup routines.
1214  *      a) Subfunctions work for either endpoint or association
1215  *      b) Single interface to lookup allows hiding the lookup lock rather
1216  *         than acquiring it externally.
1217  *   2) Common interface for the inbound chunk handling/state machine.
1218  *   3) Common object handling routines for reference counting, etc.
1219  *   4) Disentangle association lookup from endpoint lookup, where we
1220  *      do not have to find our endpoint to find our association.
1221  *
1222  */
1223 
1224 struct sctp_ep_common {
1225         /* Fields to help us manage our entries in the hash tables. */
1226         struct hlist_node node;
1227         int hashent;
1228 
1229         /* Runtime type information.  What kind of endpoint is this? */
1230         enum sctp_endpoint_type type;
1231 
1232         /* Some fields to help us manage this object.
1233          *   refcnt   - Reference count access to this object.
1234          *   dead     - Do not attempt to use this object.
1235          */
1236         refcount_t    refcnt;
1237         bool        dead;
1238 
1239         /* What socket does this endpoint belong to?  */
1240         struct sock *sk;
1241 
1242         /* Cache netns and it won't change once set */
1243         struct net *net;
1244 
1245         /* This is where we receive inbound chunks.  */
1246         struct sctp_inq   inqueue;
1247 
1248         /* This substructure includes the defining parameters of the
1249          * endpoint:
1250          * bind_addr.port is our shared port number.
1251          * bind_addr.address_list is our set of local IP addresses.
1252          */
1253         struct sctp_bind_addr bind_addr;
1254 };
1255 
1256 
1257 /* RFC Section 1.4 Key Terms
1258  *
1259  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1260  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1261  *   combination of a set of eligible destination transport addresses to
1262  *   which SCTP packets can be sent and a set of eligible source
1263  *   transport addresses from which SCTP packets can be received.
1264  *   All transport addresses used by an SCTP endpoint must use the
1265  *   same port number, but can use multiple IP addresses. A transport
1266  *   address used by an SCTP endpoint must not be used by another
1267  *   SCTP endpoint. In other words, a transport address is unique
1268  *   to an SCTP endpoint.
1269  *
1270  * From an implementation perspective, each socket has one of these.
1271  * A TCP-style socket will have exactly one association on one of
1272  * these.  An UDP-style socket will have multiple associations hanging
1273  * off one of these.
1274  */
1275 
1276 struct sctp_endpoint {
1277         /* Common substructure for endpoint and association. */
1278         struct sctp_ep_common base;
1279 
1280         /* Associations: A list of current associations and mappings
1281          *            to the data consumers for each association. This
1282          *            may be in the form of a hash table or other
1283          *            implementation dependent structure. The data
1284          *            consumers may be process identification
1285          *            information such as file descriptors, named pipe
1286          *            pointer, or table pointers dependent on how SCTP
1287          *            is implemented.
1288          */
1289         /* This is really a list of struct sctp_association entries. */
1290         struct list_head asocs;
1291 
1292         /* Secret Key: A secret key used by this endpoint to compute
1293          *            the MAC.  This SHOULD be a cryptographic quality
1294          *            random number with a sufficient length.
1295          *            Discussion in [RFC1750] can be helpful in
1296          *            selection of the key.
1297          */
1298         __u8 secret_key[SCTP_SECRET_SIZE];
1299 
1300         /* digest:  This is a digest of the sctp cookie.  This field is
1301          *          only used on the receive path when we try to validate
1302          *          that the cookie has not been tampered with.  We put
1303          *          this here so we pre-allocate this once and can re-use
1304          *          on every receive.
1305          */
1306         __u8 *digest;
1307  
1308         /* sendbuf acct. policy.        */
1309         __u32 sndbuf_policy;
1310 
1311         /* rcvbuf acct. policy. */
1312         __u32 rcvbuf_policy;
1313 
1314         /* SCTP AUTH: array of the HMACs that will be allocated
1315          * we need this per association so that we don't serialize
1316          */
1317         struct crypto_shash **auth_hmacs;
1318 
1319         /* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1320          struct sctp_hmac_algo_param *auth_hmacs_list;
1321 
1322         /* SCTP-AUTH: chunks to authenticate encoded into parameter */
1323         struct sctp_chunks_param *auth_chunk_list;
1324 
1325         /* SCTP-AUTH: endpoint shared keys */
1326         struct list_head endpoint_shared_keys;
1327         __u16 active_key_id;
1328         __u8  ecn_enable:1,
1329               auth_enable:1,
1330               intl_enable:1,
1331               prsctp_enable:1,
1332               asconf_enable:1,
1333               reconf_enable:1;
1334 
1335         __u8  strreset_enable;
1336 
1337         /* Security identifiers from incoming (INIT). These are set by
1338          * security_sctp_assoc_request(). These will only be used by
1339          * SCTP TCP type sockets and peeled off connections as they
1340          * cause a new socket to be generated. security_sctp_sk_clone()
1341          * will then plug these into the new socket.
1342          */
1343 
1344         u32 secid;
1345         u32 peer_secid;
1346 };
1347 
1348 /* Recover the outter endpoint structure. */
1349 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1350 {
1351         struct sctp_endpoint *ep;
1352 
1353         ep = container_of(base, struct sctp_endpoint, base);
1354         return ep;
1355 }
1356 
1357 /* These are function signatures for manipulating endpoints.  */
1358 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1359 void sctp_endpoint_free(struct sctp_endpoint *);
1360 void sctp_endpoint_put(struct sctp_endpoint *);
1361 void sctp_endpoint_hold(struct sctp_endpoint *);
1362 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1363 struct sctp_association *sctp_endpoint_lookup_assoc(
1364         const struct sctp_endpoint *ep,
1365         const union sctp_addr *paddr,
1366         struct sctp_transport **);
1367 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1368                                  const union sctp_addr *paddr);
1369 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1370                                         struct net *, const union sctp_addr *);
1371 bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1372                           const union sctp_addr *paddr);
1373 
1374 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1375                      const struct sctp_association *asoc,
1376                      enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1377                      struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1378 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1379                       const union sctp_addr *peer,
1380                       struct sctp_init_chunk *init, gfp_t gfp);
1381 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1382 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1383 
1384 struct sctp_inithdr_host {
1385         __u32 init_tag;
1386         __u32 a_rwnd;
1387         __u16 num_outbound_streams;
1388         __u16 num_inbound_streams;
1389         __u32 initial_tsn;
1390 };
1391 
1392 struct sctp_stream_priorities {
1393         /* List of priorities scheduled */
1394         struct list_head prio_sched;
1395         /* List of streams scheduled */
1396         struct list_head active;
1397         /* The next stream stream in line */
1398         struct sctp_stream_out_ext *next;
1399         __u16 prio;
1400 };
1401 
1402 struct sctp_stream_out_ext {
1403         __u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1404         __u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1405         struct list_head outq; /* chunks enqueued by this stream */
1406         union {
1407                 struct {
1408                         /* Scheduled streams list */
1409                         struct list_head prio_list;
1410                         struct sctp_stream_priorities *prio_head;
1411                 };
1412                 /* Fields used by RR scheduler */
1413                 struct {
1414                         struct list_head rr_list;
1415                 };
1416         };
1417 };
1418 
1419 struct sctp_stream_out {
1420         union {
1421                 __u32 mid;
1422                 __u16 ssn;
1423         };
1424         __u32 mid_uo;
1425         struct sctp_stream_out_ext *ext;
1426         __u8 state;
1427 };
1428 
1429 struct sctp_stream_in {
1430         union {
1431                 __u32 mid;
1432                 __u16 ssn;
1433         };
1434         __u32 mid_uo;
1435         __u32 fsn;
1436         __u32 fsn_uo;
1437         char pd_mode;
1438         char pd_mode_uo;
1439 };
1440 
1441 struct sctp_stream {
1442         GENRADIX(struct sctp_stream_out) out;
1443         GENRADIX(struct sctp_stream_in) in;
1444 
1445         __u16 outcnt;
1446         __u16 incnt;
1447         /* Current stream being sent, if any */
1448         struct sctp_stream_out *out_curr;
1449         union {
1450                 /* Fields used by priority scheduler */
1451                 struct {
1452                         /* List of priorities scheduled */
1453                         struct list_head prio_list;
1454                 };
1455                 /* Fields used by RR scheduler */
1456                 struct {
1457                         /* List of streams scheduled */
1458                         struct list_head rr_list;
1459                         /* The next stream stream in line */
1460                         struct sctp_stream_out_ext *rr_next;
1461                 };
1462         };
1463         struct sctp_stream_interleave *si;
1464 };
1465 
1466 static inline struct sctp_stream_out *sctp_stream_out(
1467         struct sctp_stream *stream,
1468         __u16 sid)
1469 {
1470         return genradix_ptr(&stream->out, sid);
1471 }
1472 
1473 static inline struct sctp_stream_in *sctp_stream_in(
1474         struct sctp_stream *stream,
1475         __u16 sid)
1476 {
1477         return genradix_ptr(&stream->in, sid);
1478 }
1479 
1480 #define SCTP_SO(s, i) sctp_stream_out((s), (i))
1481 #define SCTP_SI(s, i) sctp_stream_in((s), (i))
1482 
1483 #define SCTP_STREAM_CLOSED              0x00
1484 #define SCTP_STREAM_OPEN                0x01
1485 
1486 static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1487 {
1488         return stream->si->data_chunk_len;
1489 }
1490 
1491 static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1492 {
1493         return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1494 }
1495 
1496 static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1497 {
1498         return stream->si->ftsn_chunk_len;
1499 }
1500 
1501 static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1502 {
1503         return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1504 }
1505 
1506 /* SCTP_GET_ASSOC_STATS counters */
1507 struct sctp_priv_assoc_stats {
1508         /* Maximum observed rto in the association during subsequent
1509          * observations. Value is set to 0 if no RTO measurement took place
1510          * The transport where the max_rto was observed is returned in
1511          * obs_rto_ipaddr
1512          */
1513         struct sockaddr_storage obs_rto_ipaddr;
1514         __u64 max_obs_rto;
1515         /* Total In and Out SACKs received and sent */
1516         __u64 isacks;
1517         __u64 osacks;
1518         /* Total In and Out packets received and sent */
1519         __u64 opackets;
1520         __u64 ipackets;
1521         /* Total retransmitted chunks */
1522         __u64 rtxchunks;
1523         /* TSN received > next expected */
1524         __u64 outofseqtsns;
1525         /* Duplicate Chunks received */
1526         __u64 idupchunks;
1527         /* Gap Ack Blocks received */
1528         __u64 gapcnt;
1529         /* Unordered data chunks sent and received */
1530         __u64 ouodchunks;
1531         __u64 iuodchunks;
1532         /* Ordered data chunks sent and received */
1533         __u64 oodchunks;
1534         __u64 iodchunks;
1535         /* Control chunks sent and received */
1536         __u64 octrlchunks;
1537         __u64 ictrlchunks;
1538 };
1539 
1540 /* RFC2960
1541  *
1542  * 12. Recommended Transmission Control Block (TCB) Parameters
1543  *
1544  * This section details a recommended set of parameters that should
1545  * be contained within the TCB for an implementation. This section is
1546  * for illustrative purposes and should not be deemed as requirements
1547  * on an implementation or as an exhaustive list of all parameters
1548  * inside an SCTP TCB. Each implementation may need its own additional
1549  * parameters for optimization.
1550  */
1551 
1552 
1553 /* Here we have information about each individual association. */
1554 struct sctp_association {
1555 
1556         /* A base structure common to endpoint and association.
1557          * In this context, it represents the associations's view
1558          * of the local endpoint of the association.
1559          */
1560         struct sctp_ep_common base;
1561 
1562         /* Associations on the same socket. */
1563         struct list_head asocs;
1564 
1565         /* association id. */
1566         sctp_assoc_t assoc_id;
1567 
1568         /* This is our parent endpoint.  */
1569         struct sctp_endpoint *ep;
1570 
1571         /* These are those association elements needed in the cookie.  */
1572         struct sctp_cookie c;
1573 
1574         /* This is all information about our peer.  */
1575         struct {
1576                 /* transport_addr_list
1577                  *
1578                  * Peer        : A list of SCTP transport addresses that the
1579                  * Transport   : peer is bound to. This information is derived
1580                  * Address     : from the INIT or INIT ACK and is used to
1581                  * List        : associate an inbound packet with a given
1582                  *             : association. Normally this information is
1583                  *             : hashed or keyed for quick lookup and access
1584                  *             : of the TCB.
1585                  *             : The list is also initialized with the list
1586                  *             : of addresses passed with the sctp_connectx()
1587                  *             : call.
1588                  *
1589                  * It is a list of SCTP_transport's.
1590                  */
1591                 struct list_head transport_addr_list;
1592 
1593                 /* rwnd
1594                  *
1595                  * Peer Rwnd   : Current calculated value of the peer's rwnd.
1596                  */
1597                 __u32 rwnd;
1598 
1599                 /* transport_count
1600                  *
1601                  * Peer        : A count of the number of peer addresses
1602                  * Transport   : in the Peer Transport Address List.
1603                  * Address     :
1604                  * Count       :
1605                  */
1606                 __u16 transport_count;
1607 
1608                 /* port
1609                  *   The transport layer port number.
1610                  */
1611                 __u16 port;
1612 
1613                 /* primary_path
1614                  *
1615                  * Primary     : This is the current primary destination
1616                  * Path        : transport address of the peer endpoint.  It
1617                  *             : may also specify a source transport address
1618                  *             : on this endpoint.
1619                  *
1620                  * All of these paths live on transport_addr_list.
1621                  *
1622                  * At the bakeoffs, we discovered that the intent of
1623                  * primaryPath is that it only changes when the ULP
1624                  * asks to have it changed.  We add the activePath to
1625                  * designate the connection we are currently using to
1626                  * transmit new data and most control chunks.
1627                  */
1628                 struct sctp_transport *primary_path;
1629 
1630                 /* Cache the primary path address here, when we
1631                  * need a an address for msg_name.
1632                  */
1633                 union sctp_addr primary_addr;
1634 
1635                 /* active_path
1636                  *   The path that we are currently using to
1637                  *   transmit new data and most control chunks.
1638                  */
1639                 struct sctp_transport *active_path;
1640 
1641                 /* retran_path
1642                  *
1643                  * RFC2960 6.4 Multi-homed SCTP Endpoints
1644                  * ...
1645                  * Furthermore, when its peer is multi-homed, an
1646                  * endpoint SHOULD try to retransmit a chunk to an
1647                  * active destination transport address that is
1648                  * different from the last destination address to
1649                  * which the DATA chunk was sent.
1650                  */
1651                 struct sctp_transport *retran_path;
1652 
1653                 /* Pointer to last transport I have sent on.  */
1654                 struct sctp_transport *last_sent_to;
1655 
1656                 /* This is the last transport I have received DATA on.  */
1657                 struct sctp_transport *last_data_from;
1658 
1659                 /*
1660                  * Mapping  An array of bits or bytes indicating which out of
1661                  * Array    order TSN's have been received (relative to the
1662                  *          Last Rcvd TSN). If no gaps exist, i.e. no out of
1663                  *          order packets have been received, this array
1664                  *          will be set to all zero. This structure may be
1665                  *          in the form of a circular buffer or bit array.
1666                  *
1667                  * Last Rcvd   : This is the last TSN received in
1668                  * TSN         : sequence. This value is set initially by
1669                  *             : taking the peer's Initial TSN, received in
1670                  *             : the INIT or INIT ACK chunk, and subtracting
1671                  *             : one from it.
1672                  *
1673                  * Throughout most of the specification this is called the
1674                  * "Cumulative TSN ACK Point".  In this case, we
1675                  * ignore the advice in 12.2 in favour of the term
1676                  * used in the bulk of the text.  This value is hidden
1677                  * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1678                  */
1679                 struct sctp_tsnmap tsn_map;
1680 
1681                 /* This mask is used to disable sending the ASCONF chunk
1682                  * with specified parameter to peer.
1683                  */
1684                 __be16 addip_disabled_mask;
1685 
1686                 /* These are capabilities which our peer advertised.  */
1687                 __u16   ecn_capable:1,      /* Can peer do ECN? */
1688                         ipv4_address:1,     /* Peer understands IPv4 addresses? */
1689                         ipv6_address:1,     /* Peer understands IPv6 addresses? */
1690                         hostname_address:1, /* Peer understands DNS addresses? */
1691                         asconf_capable:1,   /* Does peer support ADDIP? */
1692                         prsctp_capable:1,   /* Can peer do PR-SCTP? */
1693                         reconf_capable:1,   /* Can peer do RE-CONFIG? */
1694                         intl_capable:1,     /* Can peer do INTERLEAVE */
1695                         auth_capable:1,     /* Is peer doing SCTP-AUTH? */
1696                         /* sack_needed:
1697                          *   This flag indicates if the next received
1698                          *   packet is to be responded to with a
1699                          *   SACK. This is initialized to 0.  When a packet
1700                          *   is received sack_cnt is incremented. If this value
1701                          *   reaches 2 or more, a SACK is sent and the
1702                          *   value is reset to 0. Note: This is used only
1703                          *   when no DATA chunks are received out of
1704                          *   order.  When DATA chunks are out of order,
1705                          *   SACK's are not delayed (see Section 6).
1706                          */
1707                         sack_needed:1,     /* Do we need to sack the peer? */
1708                         sack_generation:1,
1709                         zero_window_announced:1;
1710 
1711                 __u32   sack_cnt;
1712 
1713                 __u32   adaptation_ind;  /* Adaptation Code point. */
1714 
1715                 struct sctp_inithdr_host i;
1716                 void *cookie;
1717                 int cookie_len;
1718 
1719                 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1720                  * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1721                  * Initial TSN Value minus 1
1722                  */
1723                 __u32 addip_serial;
1724 
1725                 /* SCTP-AUTH: We need to know pears random number, hmac list
1726                  * and authenticated chunk list.  All that is part of the
1727                  * cookie and these are just pointers to those locations
1728                  */
1729                 struct sctp_random_param *peer_random;
1730                 struct sctp_chunks_param *peer_chunks;
1731                 struct sctp_hmac_algo_param *peer_hmacs;
1732         } peer;
1733 
1734         /* State       : A state variable indicating what state the
1735          *             : association is in, i.e. COOKIE-WAIT,
1736          *             : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1737          *             : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1738          *
1739          *              Note: No "CLOSED" state is illustrated since if a
1740          *              association is "CLOSED" its TCB SHOULD be removed.
1741          *
1742          *              In this implementation we DO have a CLOSED
1743          *              state which is used during initiation and shutdown.
1744          *
1745          *              State takes values from SCTP_STATE_*.
1746          */
1747         enum sctp_state state;
1748 
1749         /* Overall     : The overall association error count.
1750          * Error Count : [Clear this any time I get something.]
1751          */
1752         int overall_error_count;
1753 
1754         /* The cookie life I award for any cookie.  */
1755         ktime_t cookie_life;
1756 
1757         /* These are the association's initial, max, and min RTO values.
1758          * These values will be initialized by system defaults, but can
1759          * be modified via the SCTP_RTOINFO socket option.
1760          */
1761         unsigned long rto_initial;
1762         unsigned long rto_max;
1763         unsigned long rto_min;
1764 
1765         /* Maximum number of new data packets that can be sent in a burst.  */
1766         int max_burst;
1767 
1768         /* This is the max_retrans value for the association.  This value will
1769          * be initialized initialized from system defaults, but can be
1770          * modified by the SCTP_ASSOCINFO socket option.
1771          */
1772         int max_retrans;
1773 
1774         /* This is the partially failed retrans value for the transport
1775          * and will be initialized from the assocs value.  This can be
1776          * changed using the SCTP_PEER_ADDR_THLDS socket option
1777          */
1778         int pf_retrans;
1779 
1780         /* Maximum number of times the endpoint will retransmit INIT  */
1781         __u16 max_init_attempts;
1782 
1783         /* How many times have we resent an INIT? */
1784         __u16 init_retries;
1785 
1786         /* The largest timeout or RTO value to use in attempting an INIT */
1787         unsigned long max_init_timeo;
1788 
1789         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1790          * the destination address every heartbeat interval. This value
1791          * will be inherited by all new transports.
1792          */
1793         unsigned long hbinterval;
1794 
1795         /* This is the max_retrans value for new transports in the
1796          * association.
1797          */
1798         __u16 pathmaxrxt;
1799 
1800         __u32 flowlabel;
1801         __u8  dscp;
1802 
1803         /* Flag that path mtu update is pending */
1804         __u8   pmtu_pending;
1805 
1806         /* Association : The smallest PMTU discovered for all of the
1807          * PMTU        : peer's transport addresses.
1808          */
1809         __u32 pathmtu;
1810 
1811         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1812         __u32 param_flags;
1813 
1814         __u32 sackfreq;
1815         /* SACK delay timeout */
1816         unsigned long sackdelay;
1817 
1818         unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1819         struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1820 
1821         /* Transport to which SHUTDOWN chunk was last sent.  */
1822         struct sctp_transport *shutdown_last_sent_to;
1823 
1824         /* Transport to which INIT chunk was last sent.  */
1825         struct sctp_transport *init_last_sent_to;
1826 
1827         /* How many times have we resent a SHUTDOWN */
1828         int shutdown_retries;
1829 
1830         /* Next TSN    : The next TSN number to be assigned to a new
1831          *             : DATA chunk.  This is sent in the INIT or INIT
1832          *             : ACK chunk to the peer and incremented each
1833          *             : time a DATA chunk is assigned a TSN
1834          *             : (normally just prior to transmit or during
1835          *             : fragmentation).
1836          */
1837         __u32 next_tsn;
1838 
1839         /*
1840          * Last Rcvd   : This is the last TSN received in sequence.  This value
1841          * TSN         : is set initially by taking the peer's Initial TSN,
1842          *             : received in the INIT or INIT ACK chunk, and
1843          *             : subtracting one from it.
1844          *
1845          * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1846          */
1847 
1848         __u32 ctsn_ack_point;
1849 
1850         /* PR-SCTP Advanced.Peer.Ack.Point */
1851         __u32 adv_peer_ack_point;
1852 
1853         /* Highest TSN that is acknowledged by incoming SACKs. */
1854         __u32 highest_sacked;
1855 
1856         /* TSN marking the fast recovery exit point */
1857         __u32 fast_recovery_exit;
1858 
1859         /* Flag to track the current fast recovery state */
1860         __u8 fast_recovery;
1861 
1862         /* The number of unacknowledged data chunks.  Reported through
1863          * the SCTP_STATUS sockopt.
1864          */
1865         __u16 unack_data;
1866 
1867         /* The total number of data chunks that we've had to retransmit
1868          * as the result of a T3 timer expiration
1869          */
1870         __u32 rtx_data_chunks;
1871 
1872         /* This is the association's receive buffer space.  This value is used
1873          * to set a_rwnd field in an INIT or a SACK chunk.
1874          */
1875         __u32 rwnd;
1876 
1877         /* This is the last advertised value of rwnd over a SACK chunk. */
1878         __u32 a_rwnd;
1879 
1880         /* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1881          * to slop over a maximum of the association's frag_point.
1882          */
1883         __u32 rwnd_over;
1884 
1885         /* Keeps treack of rwnd pressure.  This happens when we have
1886          * a window, but not recevie buffer (i.e small packets).  This one
1887          * is releases slowly (1 PMTU at a time ).
1888          */
1889         __u32 rwnd_press;
1890 
1891         /* This is the sndbuf size in use for the association.
1892          * This corresponds to the sndbuf size for the association,
1893          * as specified in the sk->sndbuf.
1894          */
1895         int sndbuf_used;
1896 
1897         /* This is the amount of memory that this association has allocated
1898          * in the receive path at any given time.
1899          */
1900         atomic_t rmem_alloc;
1901 
1902         /* This is the wait queue head for send requests waiting on
1903          * the association sndbuf space.
1904          */
1905         wait_queue_head_t       wait;
1906 
1907         /* The message size at which SCTP fragmentation will occur. */
1908         __u32 frag_point;
1909         __u32 user_frag;
1910 
1911         /* Counter used to count INIT errors. */
1912         int init_err_counter;
1913 
1914         /* Count the number of INIT cycles (for doubling timeout). */
1915         int init_cycle;
1916 
1917         /* Default send parameters. */
1918         __u16 default_stream;
1919         __u16 default_flags;
1920         __u32 default_ppid;
1921         __u32 default_context;
1922         __u32 default_timetolive;
1923 
1924         /* Default receive parameters */
1925         __u32 default_rcv_context;
1926 
1927         /* Stream arrays */
1928         struct sctp_stream stream;
1929 
1930         /* All outbound chunks go through this structure.  */
1931         struct sctp_outq outqueue;
1932 
1933         /* A smart pipe that will handle reordering and fragmentation,
1934          * as well as handle passing events up to the ULP.
1935          */
1936         struct sctp_ulpq ulpq;
1937 
1938         /* Last TSN that caused an ECNE Chunk to be sent.  */
1939         __u32 last_ecne_tsn;
1940 
1941         /* Last TSN that caused a CWR Chunk to be sent.  */
1942         __u32 last_cwr_tsn;
1943 
1944         /* How many duplicated TSNs have we seen?  */
1945         int numduptsns;
1946 
1947         /* These are to support
1948          * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1949          *  and Enforcement of Flow and Message Limits"
1950          * <draft-ietf-tsvwg-addip-sctp-02.txt>
1951          * or "ADDIP" for short.
1952          */
1953 
1954 
1955 
1956         /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1957          *
1958          * R1) One and only one ASCONF Chunk MAY be in transit and
1959          * unacknowledged at any one time.  If a sender, after sending
1960          * an ASCONF chunk, decides it needs to transfer another
1961          * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1962          * returns from the previous ASCONF Chunk before sending a
1963          * subsequent ASCONF. Note this restriction binds each side,
1964          * so at any time two ASCONF may be in-transit on any given
1965          * association (one sent from each endpoint).
1966          *
1967          * [This is our one-and-only-one ASCONF in flight.  If we do
1968          * not have an ASCONF in flight, this is NULL.]
1969          */
1970         struct sctp_chunk *addip_last_asconf;
1971 
1972         /* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1973          *
1974          * This is needed to implement itmes E1 - E4 of the updated
1975          * spec.  Here is the justification:
1976          *
1977          * Since the peer may bundle multiple ASCONF chunks toward us,
1978          * we now need the ability to cache multiple ACKs.  The section
1979          * describes in detail how they are cached and cleaned up.
1980          */
1981         struct list_head asconf_ack_list;
1982 
1983         /* These ASCONF chunks are waiting to be sent.
1984          *
1985          * These chunaks can't be pushed to outqueue until receiving
1986          * ASCONF_ACK for the previous ASCONF indicated by
1987          * addip_last_asconf, so as to guarantee that only one ASCONF
1988          * is in flight at any time.
1989          *
1990          * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1991          *
1992          * In defining the ASCONF Chunk transfer procedures, it is
1993          * essential that these transfers MUST NOT cause congestion
1994          * within the network.  To achieve this, we place these
1995          * restrictions on the transfer of ASCONF Chunks:
1996          *
1997          * R1) One and only one ASCONF Chunk MAY be in transit and
1998          * unacknowledged at any one time.  If a sender, after sending
1999          * an ASCONF chunk, decides it needs to transfer another
2000          * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
2001          * returns from the previous ASCONF Chunk before sending a
2002          * subsequent ASCONF. Note this restriction binds each side,
2003          * so at any time two ASCONF may be in-transit on any given
2004          * association (one sent from each endpoint).
2005          *
2006          *
2007          * [I really think this is EXACTLY the sort of intelligence
2008          *  which already resides in sctp_outq.  Please move this
2009          *  queue and its supporting logic down there.  --piggy]
2010          */
2011         struct list_head addip_chunk_list;
2012 
2013         /* ADDIP Section 4.1 ASCONF Chunk Procedures
2014          *
2015          * A2) A serial number should be assigned to the Chunk. The
2016          * serial number SHOULD be a monotonically increasing
2017          * number. The serial number SHOULD be initialized at
2018          * the start of the association to the same value as the
2019          * Initial TSN and every time a new ASCONF chunk is created
2020          * it is incremented by one after assigning the serial number
2021          * to the newly created chunk.
2022          *
2023          * ADDIP
2024          * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
2025          *
2026          * Serial Number : 32 bits (unsigned integer)
2027          *
2028          * This value represents a Serial Number for the ASCONF
2029          * Chunk. The valid range of Serial Number is from 0 to
2030          * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
2031          * after reaching 4294967295.
2032          */
2033         __u32 addip_serial;
2034         int src_out_of_asoc_ok;
2035         union sctp_addr *asconf_addr_del_pending;
2036         struct sctp_transport *new_transport;
2037 
2038         /* SCTP AUTH: list of the endpoint shared keys.  These
2039          * keys are provided out of band by the user applicaton
2040          * and can't change during the lifetime of the association
2041          */
2042         struct list_head endpoint_shared_keys;
2043 
2044         /* SCTP AUTH:
2045          * The current generated assocaition shared key (secret)
2046          */
2047         struct sctp_auth_bytes *asoc_shared_key;
2048         struct sctp_shared_key *shkey;
2049 
2050         /* SCTP AUTH: hmac id of the first peer requested algorithm
2051          * that we support.
2052          */
2053         __u16 default_hmac_id;
2054 
2055         __u16 active_key_id;
2056 
2057         __u8 need_ecne:1,       /* Need to send an ECNE Chunk? */
2058              temp:1,            /* Is it a temporary association? */
2059              force_delay:1;
2060 
2061         __u8 strreset_enable;
2062         __u8 strreset_outstanding; /* request param count on the fly */
2063 
2064         __u32 strreset_outseq; /* Update after receiving response */
2065         __u32 strreset_inseq; /* Update after receiving request */
2066         __u32 strreset_result[2]; /* save the results of last 2 responses */
2067 
2068         struct sctp_chunk *strreset_chunk; /* save request chunk */
2069 
2070         struct sctp_priv_assoc_stats stats;
2071 
2072         int sent_cnt_removable;
2073 
2074         __u16 subscribe;
2075 
2076         __u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2077         __u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2078 
2079         struct rcu_head rcu;
2080 };
2081 
2082 
2083 /* An eyecatcher for determining if we are really looking at an
2084  * association data structure.
2085  */
2086 enum {
2087         SCTP_ASSOC_EYECATCHER = 0xa550c123,
2088 };
2089 
2090 /* Recover the outter association structure. */
2091 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2092 {
2093         struct sctp_association *asoc;
2094 
2095         asoc = container_of(base, struct sctp_association, base);
2096         return asoc;
2097 }
2098 
2099 /* These are function signatures for manipulating associations.  */
2100 
2101 
2102 struct sctp_association *
2103 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2104                      enum sctp_scope scope, gfp_t gfp);
2105 void sctp_association_free(struct sctp_association *);
2106 void sctp_association_put(struct sctp_association *);
2107 void sctp_association_hold(struct sctp_association *);
2108 
2109 struct sctp_transport *sctp_assoc_choose_alter_transport(
2110         struct sctp_association *, struct sctp_transport *);
2111 void sctp_assoc_update_retran_path(struct sctp_association *);
2112 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2113                                           const union sctp_addr *);
2114 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2115                             const union sctp_addr *laddr);
2116 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2117                                      const union sctp_addr *address,
2118                                      const gfp_t gfp,
2119                                      const int peer_state);
2120 void sctp_assoc_del_peer(struct sctp_association *asoc,
2121                          const union sctp_addr *addr);
2122 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2123                          struct sctp_transport *peer);
2124 void sctp_assoc_control_transport(struct sctp_association *asoc,
2125                                   struct sctp_transport *transport,
2126                                   enum sctp_transport_cmd command,
2127                                   sctp_sn_error_t error);
2128 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2129 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2130 int sctp_assoc_update(struct sctp_association *old,
2131                       struct sctp_association *new);
2132 
2133 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2134 
2135 void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2136 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2137 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2138 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2139 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2140 void sctp_assoc_set_primary(struct sctp_association *,
2141                             struct sctp_transport *);
2142 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2143                                     struct sctp_transport *);
2144 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2145                                      enum sctp_scope scope, gfp_t gfp);
2146 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2147                                          struct sctp_cookie*,
2148                                          gfp_t gfp);
2149 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2150 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2151 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2152                                         const struct sctp_association *asoc,
2153                                         __be32 serial);
2154 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2155 
2156 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2157                         const union sctp_addr *ss2);
2158 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2159 
2160 /* A convenience structure to parse out SCTP specific CMSGs. */
2161 struct sctp_cmsgs {
2162         struct sctp_initmsg *init;
2163         struct sctp_sndrcvinfo *srinfo;
2164         struct sctp_sndinfo *sinfo;
2165         struct sctp_prinfo *prinfo;
2166         struct sctp_authinfo *authinfo;
2167         struct msghdr *addrs_msg;
2168 };
2169 
2170 /* Structure for tracking memory objects */
2171 struct sctp_dbg_objcnt_entry {
2172         char *label;
2173         atomic_t *counter;
2174 };
2175 
2176 #endif /* __sctp_structs_h__ */

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