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TOMOYO Linux Cross Reference
Linux/include/net/sctp/structs.h

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  1 /* SCTP kernel implementation
  2  * (C) Copyright IBM Corp. 2001, 2004
  3  * Copyright (c) 1999-2000 Cisco, Inc.
  4  * Copyright (c) 1999-2001 Motorola, Inc.
  5  * Copyright (c) 2001 Intel Corp.
  6  *
  7  * This file is part of the SCTP kernel implementation
  8  *
  9  * This SCTP implementation is free software;
 10  * you can redistribute it and/or modify it under the terms of
 11  * the GNU General Public License as published by
 12  * the Free Software Foundation; either version 2, or (at your option)
 13  * any later version.
 14  *
 15  * This SCTP implementation is distributed in the hope that it
 16  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 17  *                 ************************
 18  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 19  * See the GNU General Public License for more details.
 20  *
 21  * You should have received a copy of the GNU General Public License
 22  * along with GNU CC; see the file COPYING.  If not, write to
 23  * the Free Software Foundation, 59 Temple Place - Suite 330,
 24  * Boston, MA 02111-1307, USA.
 25  *
 26  * Please send any bug reports or fixes you make to the
 27  * email addresses:
 28  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
 29  *
 30  * Or submit a bug report through the following website:
 31  *    http://www.sf.net/projects/lksctp
 32  *
 33  * Written or modified by:
 34  *    Randall Stewart       <randall@sctp.chicago.il.us>
 35  *    Ken Morneau           <kmorneau@cisco.com>
 36  *    Qiaobing Xie          <qxie1@email.mot.com>
 37  *    La Monte H.P. Yarroll <piggy@acm.org>
 38  *    Karl Knutson          <karl@athena.chicago.il.us>
 39  *    Jon Grimm             <jgrimm@us.ibm.com>
 40  *    Xingang Guo           <xingang.guo@intel.com>
 41  *    Hui Huang             <hui.huang@nokia.com>
 42  *    Sridhar Samudrala     <sri@us.ibm.com>
 43  *    Daisy Chang           <daisyc@us.ibm.com>
 44  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
 45  *    Ardelle Fan           <ardelle.fan@intel.com>
 46  *    Ryan Layer            <rmlayer@us.ibm.com>
 47  *    Anup Pemmaiah         <pemmaiah@cc.usu.edu>
 48  *    Kevin Gao             <kevin.gao@intel.com>
 49  *
 50  * Any bugs reported given to us we will try to fix... any fixes shared will
 51  * be incorporated into the next SCTP release.
 52  */
 53 
 54 #ifndef __sctp_structs_h__
 55 #define __sctp_structs_h__
 56 
 57 #include <linux/time.h>         /* We get struct timespec.    */
 58 #include <linux/socket.h>       /* linux/in.h needs this!!    */
 59 #include <linux/in.h>           /* We get struct sockaddr_in. */
 60 #include <linux/in6.h>          /* We get struct in6_addr     */
 61 #include <linux/ipv6.h>
 62 #include <asm/param.h>          /* We get MAXHOSTNAMELEN.     */
 63 #include <linux/atomic.h>               /* This gets us atomic counters.  */
 64 #include <linux/skbuff.h>       /* We need sk_buff_head. */
 65 #include <linux/workqueue.h>    /* We need tq_struct.    */
 66 #include <linux/sctp.h>         /* We need sctp* header structs.  */
 67 #include <net/sctp/auth.h>      /* We need auth specific structs */
 68 
 69 /* A convenience structure for handling sockaddr structures.
 70  * We should wean ourselves off this.
 71  */
 72 union sctp_addr {
 73         struct sockaddr_in v4;
 74         struct sockaddr_in6 v6;
 75         struct sockaddr sa;
 76 };
 77 
 78 /* Forward declarations for data structures. */
 79 struct sctp_globals;
 80 struct sctp_endpoint;
 81 struct sctp_association;
 82 struct sctp_transport;
 83 struct sctp_packet;
 84 struct sctp_chunk;
 85 struct sctp_inq;
 86 struct sctp_outq;
 87 struct sctp_bind_addr;
 88 struct sctp_ulpq;
 89 struct sctp_ep_common;
 90 struct sctp_ssnmap;
 91 struct crypto_hash;
 92 
 93 
 94 #include <net/sctp/tsnmap.h>
 95 #include <net/sctp/ulpevent.h>
 96 #include <net/sctp/ulpqueue.h>
 97 
 98 /* Structures useful for managing bind/connect. */
 99 
100 struct sctp_bind_bucket {
101         unsigned short  port;
102         unsigned short  fastreuse;
103         struct hlist_node       node;
104         struct hlist_head       owner;
105 };
106 
107 struct sctp_bind_hashbucket {
108         spinlock_t      lock;
109         struct hlist_head       chain;
110 };
111 
112 /* Used for hashing all associations.  */
113 struct sctp_hashbucket {
114         rwlock_t        lock;
115         struct hlist_head       chain;
116 } __attribute__((__aligned__(8)));
117 
118 
119 /* The SCTP globals structure. */
120 extern struct sctp_globals {
121         /* RFC2960 Section 14. Suggested SCTP Protocol Parameter Values
122          *
123          * The following protocol parameters are RECOMMENDED:
124          *
125          * RTO.Initial              - 3  seconds
126          * RTO.Min                  - 1  second
127          * RTO.Max                 -  60 seconds
128          * RTO.Alpha                - 1/8  (3 when converted to right shifts.)
129          * RTO.Beta                 - 1/4  (2 when converted to right shifts.)
130          */
131         unsigned int rto_initial;
132         unsigned int rto_min;
133         unsigned int rto_max;
134 
135         /* Note: rto_alpha and rto_beta are really defined as inverse
136          * powers of two to facilitate integer operations.
137          */
138         int rto_alpha;
139         int rto_beta;
140 
141         /* Max.Burst                - 4 */
142         int max_burst;
143 
144         /* Whether Cookie Preservative is enabled(1) or not(0) */
145         int cookie_preserve_enable;
146 
147         /* Valid.Cookie.Life        - 60  seconds  */
148         unsigned int valid_cookie_life;
149 
150         /* Delayed SACK timeout  200ms default*/
151         unsigned int sack_timeout;
152 
153         /* HB.interval              - 30 seconds  */
154         unsigned int hb_interval;
155 
156         /* Association.Max.Retrans  - 10 attempts
157          * Path.Max.Retrans         - 5  attempts (per destination address)
158          * Max.Init.Retransmits     - 8  attempts
159          */
160         int max_retrans_association;
161         int max_retrans_path;
162         int max_retrans_init;
163 
164         /*
165          * Policy for preforming sctp/socket accounting
166          * 0   - do socket level accounting, all assocs share sk_sndbuf
167          * 1   - do sctp accounting, each asoc may use sk_sndbuf bytes
168          */
169         int sndbuf_policy;
170 
171         /*
172          * Policy for preforming sctp/socket accounting
173          * 0   - do socket level accounting, all assocs share sk_rcvbuf
174          * 1   - do sctp accounting, each asoc may use sk_rcvbuf bytes
175          */
176         int rcvbuf_policy;
177 
178         /* The following variables are implementation specific.  */
179 
180         /* Default initialization values to be applied to new associations. */
181         __u16 max_instreams;
182         __u16 max_outstreams;
183 
184         /* This is a list of groups of functions for each address
185          * family that we support.
186          */
187         struct list_head address_families;
188 
189         /* This is the hash of all endpoints. */
190         int ep_hashsize;
191         struct sctp_hashbucket *ep_hashtable;
192 
193         /* This is the hash of all associations. */
194         int assoc_hashsize;
195         struct sctp_hashbucket *assoc_hashtable;
196 
197         /* This is the sctp port control hash.  */
198         int port_hashsize;
199         struct sctp_bind_hashbucket *port_hashtable;
200 
201         /* This is the global local address list.
202          * We actively maintain this complete list of addresses on
203          * the system by catching address add/delete events.
204          *
205          * It is a list of sctp_sockaddr_entry.
206          */
207         struct list_head local_addr_list;
208         int default_auto_asconf;
209         struct list_head addr_waitq;
210         struct timer_list addr_wq_timer;
211         struct list_head auto_asconf_splist;
212         /* Lock that protects both addr_waitq and auto_asconf_splist */
213         spinlock_t addr_wq_lock;
214 
215         /* Lock that protects the local_addr_list writers */
216         spinlock_t addr_list_lock;
217         
218         /* Flag to indicate if addip is enabled. */
219         int addip_enable;
220         int addip_noauth_enable;
221 
222         /* Flag to indicate if PR-SCTP is enabled. */
223         int prsctp_enable;
224 
225         /* Flag to idicate if SCTP-AUTH is enabled */
226         int auth_enable;
227 
228         /*
229          * Policy to control SCTP IPv4 address scoping
230          * 0   - Disable IPv4 address scoping
231          * 1   - Enable IPv4 address scoping
232          * 2   - Selectively allow only IPv4 private addresses
233          * 3   - Selectively allow only IPv4 link local address
234          */
235         int ipv4_scope_policy;
236 
237         /* Flag to indicate whether computing and verifying checksum
238          * is disabled. */
239         bool checksum_disable;
240 
241         /* Threshold for rwnd update SACKS.  Receive buffer shifted this many
242          * bits is an indicator of when to send and window update SACK.
243          */
244         int rwnd_update_shift;
245 
246         /* Threshold for autoclose timeout, in seconds. */
247         unsigned long max_autoclose;
248 } sctp_globals;
249 
250 #define sctp_rto_initial                (sctp_globals.rto_initial)
251 #define sctp_rto_min                    (sctp_globals.rto_min)
252 #define sctp_rto_max                    (sctp_globals.rto_max)
253 #define sctp_rto_alpha                  (sctp_globals.rto_alpha)
254 #define sctp_rto_beta                   (sctp_globals.rto_beta)
255 #define sctp_max_burst                  (sctp_globals.max_burst)
256 #define sctp_valid_cookie_life          (sctp_globals.valid_cookie_life)
257 #define sctp_cookie_preserve_enable     (sctp_globals.cookie_preserve_enable)
258 #define sctp_max_retrans_association    (sctp_globals.max_retrans_association)
259 #define sctp_sndbuf_policy              (sctp_globals.sndbuf_policy)
260 #define sctp_rcvbuf_policy              (sctp_globals.rcvbuf_policy)
261 #define sctp_max_retrans_path           (sctp_globals.max_retrans_path)
262 #define sctp_max_retrans_init           (sctp_globals.max_retrans_init)
263 #define sctp_sack_timeout               (sctp_globals.sack_timeout)
264 #define sctp_hb_interval                (sctp_globals.hb_interval)
265 #define sctp_max_instreams              (sctp_globals.max_instreams)
266 #define sctp_max_outstreams             (sctp_globals.max_outstreams)
267 #define sctp_address_families           (sctp_globals.address_families)
268 #define sctp_ep_hashsize                (sctp_globals.ep_hashsize)
269 #define sctp_ep_hashtable               (sctp_globals.ep_hashtable)
270 #define sctp_assoc_hashsize             (sctp_globals.assoc_hashsize)
271 #define sctp_assoc_hashtable            (sctp_globals.assoc_hashtable)
272 #define sctp_port_hashsize              (sctp_globals.port_hashsize)
273 #define sctp_port_hashtable             (sctp_globals.port_hashtable)
274 #define sctp_local_addr_list            (sctp_globals.local_addr_list)
275 #define sctp_local_addr_lock            (sctp_globals.addr_list_lock)
276 #define sctp_auto_asconf_splist         (sctp_globals.auto_asconf_splist)
277 #define sctp_addr_waitq                 (sctp_globals.addr_waitq)
278 #define sctp_addr_wq_timer              (sctp_globals.addr_wq_timer)
279 #define sctp_addr_wq_lock               (sctp_globals.addr_wq_lock)
280 #define sctp_default_auto_asconf        (sctp_globals.default_auto_asconf)
281 #define sctp_scope_policy               (sctp_globals.ipv4_scope_policy)
282 #define sctp_addip_enable               (sctp_globals.addip_enable)
283 #define sctp_addip_noauth               (sctp_globals.addip_noauth_enable)
284 #define sctp_prsctp_enable              (sctp_globals.prsctp_enable)
285 #define sctp_auth_enable                (sctp_globals.auth_enable)
286 #define sctp_checksum_disable           (sctp_globals.checksum_disable)
287 #define sctp_rwnd_upd_shift             (sctp_globals.rwnd_update_shift)
288 #define sctp_max_autoclose              (sctp_globals.max_autoclose)
289 
290 /* SCTP Socket type: UDP or TCP style. */
291 typedef enum {
292         SCTP_SOCKET_UDP = 0,
293         SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
294         SCTP_SOCKET_TCP
295 } sctp_socket_type_t;
296 
297 /* Per socket SCTP information. */
298 struct sctp_sock {
299         /* inet_sock has to be the first member of sctp_sock */
300         struct inet_sock inet;
301         /* What kind of a socket is this? */
302         sctp_socket_type_t type;
303 
304         /* PF_ family specific functions.  */
305         struct sctp_pf *pf;
306 
307         /* Access to HMAC transform. */
308         struct crypto_hash *hmac;
309 
310         /* What is our base endpointer? */
311         struct sctp_endpoint *ep;
312 
313         struct sctp_bind_bucket *bind_hash;
314         /* Various Socket Options.  */
315         __u16 default_stream;
316         __u32 default_ppid;
317         __u16 default_flags;
318         __u32 default_context;
319         __u32 default_timetolive;
320         __u32 default_rcv_context;
321         int max_burst;
322 
323         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
324          * the destination address every heartbeat interval. This value
325          * will be inherited by all new associations.
326          */
327         __u32 hbinterval;
328 
329         /* This is the max_retrans value for new associations. */
330         __u16 pathmaxrxt;
331 
332         /* The initial Path MTU to use for new associations. */
333         __u32 pathmtu;
334 
335         /* The default SACK delay timeout for new associations. */
336         __u32 sackdelay;
337         __u32 sackfreq;
338 
339         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
340         __u32 param_flags;
341 
342         struct sctp_initmsg initmsg;
343         struct sctp_rtoinfo rtoinfo;
344         struct sctp_paddrparams paddrparam;
345         struct sctp_event_subscribe subscribe;
346         struct sctp_assocparams assocparams;
347         int user_frag;
348         __u32 autoclose;
349         __u8 nodelay;
350         __u8 disable_fragments;
351         __u8 v4mapped;
352         __u8 frag_interleave;
353         __u32 adaptation_ind;
354         __u32 pd_point;
355 
356         atomic_t pd_mode;
357         /* Receive to here while partial delivery is in effect. */
358         struct sk_buff_head pd_lobby;
359 
360         /* These must be the last fields, as they will skipped on copies,
361          * like on accept and peeloff operations
362          */
363         struct list_head auto_asconf_list;
364         int do_auto_asconf;
365 };
366 
367 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
368 {
369        return (struct sctp_sock *)sk;
370 }
371 
372 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
373 {
374        return (struct sock *)sp;
375 }
376 
377 #if IS_ENABLED(CONFIG_IPV6)
378 struct sctp6_sock {
379        struct sctp_sock  sctp;
380        struct ipv6_pinfo inet6;
381 };
382 #endif /* CONFIG_IPV6 */
383 
384 
385 /* This is our APPLICATION-SPECIFIC state cookie.
386  * THIS IS NOT DICTATED BY THE SPECIFICATION.
387  */
388 /* These are the parts of an association which we send in the cookie.
389  * Most of these are straight out of:
390  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
391  *
392  */
393 
394 struct sctp_cookie {
395 
396         /* My          : Tag expected in every inbound packet and sent
397          * Verification: in the INIT or INIT ACK chunk.
398          * Tag         :
399          */
400         __u32 my_vtag;
401 
402         /* Peer's      : Tag expected in every outbound packet except
403          * Verification: in the INIT chunk.
404          * Tag         :
405          */
406         __u32 peer_vtag;
407 
408         /* The rest of these are not from the spec, but really need to
409          * be in the cookie.
410          */
411 
412         /* My Tie Tag  : Assist in discovering a restarting association. */
413         __u32 my_ttag;
414 
415         /* Peer's Tie Tag: Assist in discovering a restarting association. */
416         __u32 peer_ttag;
417 
418         /* When does this cookie expire? */
419         struct timeval expiration;
420 
421         /* Number of inbound/outbound streams which are set
422          * and negotiated during the INIT process.
423          */
424         __u16 sinit_num_ostreams;
425         __u16 sinit_max_instreams;
426 
427         /* This is the first sequence number I used.  */
428         __u32 initial_tsn;
429 
430         /* This holds the originating address of the INIT packet.  */
431         union sctp_addr peer_addr;
432 
433         /* IG Section 2.35.3 
434          * Include the source port of the INIT-ACK
435          */
436         __u16           my_port;
437 
438         __u8 prsctp_capable;
439 
440         /* Padding for future use */
441         __u8 padding;           
442 
443         __u32 adaptation_ind;
444 
445         __u8 auth_random[sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH];
446         __u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
447         __u8 auth_chunks[sizeof(sctp_paramhdr_t) + SCTP_AUTH_MAX_CHUNKS];
448 
449         /* This is a shim for my peer's INIT packet, followed by
450          * a copy of the raw address list of the association.
451          * The length of the raw address list is saved in the
452          * raw_addr_list_len field, which will be used at the time when
453          * the association TCB is re-constructed from the cookie.
454          */
455         __u32 raw_addr_list_len;
456         struct sctp_init_chunk peer_init[0];
457 };
458 
459 
460 /* The format of our cookie that we send to our peer. */
461 struct sctp_signed_cookie {
462         __u8 signature[SCTP_SECRET_SIZE];
463         __u32 __pad;            /* force sctp_cookie alignment to 64 bits */
464         struct sctp_cookie c;
465 } __packed;
466 
467 /* This is another convenience type to allocate memory for address
468  * params for the maximum size and pass such structures around
469  * internally.
470  */
471 union sctp_addr_param {
472         struct sctp_paramhdr p;
473         struct sctp_ipv4addr_param v4;
474         struct sctp_ipv6addr_param v6;
475 };
476 
477 /* A convenience type to allow walking through the various
478  * parameters and avoid casting all over the place.
479  */
480 union sctp_params {
481         void *v;
482         struct sctp_paramhdr *p;
483         struct sctp_cookie_preserve_param *life;
484         struct sctp_hostname_param *dns;
485         struct sctp_cookie_param *cookie;
486         struct sctp_supported_addrs_param *sat;
487         struct sctp_ipv4addr_param *v4;
488         struct sctp_ipv6addr_param *v6;
489         union sctp_addr_param *addr;
490         struct sctp_adaptation_ind_param *aind;
491         struct sctp_supported_ext_param *ext;
492         struct sctp_random_param *random;
493         struct sctp_chunks_param *chunks;
494         struct sctp_hmac_algo_param *hmac_algo;
495         struct sctp_addip_param *addip;
496 };
497 
498 /* RFC 2960.  Section 3.3.5 Heartbeat.
499  *    Heartbeat Information: variable length
500  *    The Sender-specific Heartbeat Info field should normally include
501  *    information about the sender's current time when this HEARTBEAT
502  *    chunk is sent and the destination transport address to which this
503  *    HEARTBEAT is sent (see Section 8.3).
504  */
505 typedef struct sctp_sender_hb_info {
506         struct sctp_paramhdr param_hdr;
507         union sctp_addr daddr;
508         unsigned long sent_at;
509         __u64 hb_nonce;
510 } __packed sctp_sender_hb_info_t;
511 
512 /*
513  *  RFC 2960 1.3.2 Sequenced Delivery within Streams
514  *
515  *  The term "stream" is used in SCTP to refer to a sequence of user
516  *  messages that are to be delivered to the upper-layer protocol in
517  *  order with respect to other messages within the same stream.  This is
518  *  in contrast to its usage in TCP, where it refers to a sequence of
519  *  bytes (in this document a byte is assumed to be eight bits).
520  *  ...
521  *
522  *  This is the structure we use to track both our outbound and inbound
523  *  SSN, or Stream Sequence Numbers.
524  */
525 
526 struct sctp_stream {
527         __u16 *ssn;
528         unsigned int len;
529 };
530 
531 struct sctp_ssnmap {
532         struct sctp_stream in;
533         struct sctp_stream out;
534         int malloced;
535 };
536 
537 struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
538                                     gfp_t gfp);
539 void sctp_ssnmap_free(struct sctp_ssnmap *map);
540 void sctp_ssnmap_clear(struct sctp_ssnmap *map);
541 
542 /* What is the current SSN number for this stream? */
543 static inline __u16 sctp_ssn_peek(struct sctp_stream *stream, __u16 id)
544 {
545         return stream->ssn[id];
546 }
547 
548 /* Return the next SSN number for this stream.  */
549 static inline __u16 sctp_ssn_next(struct sctp_stream *stream, __u16 id)
550 {
551         return stream->ssn[id]++;
552 }
553 
554 /* Skip over this ssn and all below. */
555 static inline void sctp_ssn_skip(struct sctp_stream *stream, __u16 id, 
556                                  __u16 ssn)
557 {
558         stream->ssn[id] = ssn+1;
559 }
560               
561 /*
562  * Pointers to address related SCTP functions.
563  * (i.e. things that depend on the address family.)
564  */
565 struct sctp_af {
566         int             (*sctp_xmit)    (struct sk_buff *skb,
567                                          struct sctp_transport *);
568         int             (*setsockopt)   (struct sock *sk,
569                                          int level,
570                                          int optname,
571                                          char __user *optval,
572                                          unsigned int optlen);
573         int             (*getsockopt)   (struct sock *sk,
574                                          int level,
575                                          int optname,
576                                          char __user *optval,
577                                          int __user *optlen);
578         int             (*compat_setsockopt)    (struct sock *sk,
579                                          int level,
580                                          int optname,
581                                          char __user *optval,
582                                          unsigned int optlen);
583         int             (*compat_getsockopt)    (struct sock *sk,
584                                          int level,
585                                          int optname,
586                                          char __user *optval,
587                                          int __user *optlen);
588         void            (*get_dst)      (struct sctp_transport *t,
589                                          union sctp_addr *saddr,
590                                          struct flowi *fl,
591                                          struct sock *sk);
592         void            (*get_saddr)    (struct sctp_sock *sk,
593                                          struct sctp_transport *t,
594                                          struct flowi *fl);
595         void            (*copy_addrlist) (struct list_head *,
596                                           struct net_device *);
597         int             (*cmp_addr)     (const union sctp_addr *addr1,
598                                          const union sctp_addr *addr2);
599         void            (*addr_copy)    (union sctp_addr *dst,
600                                          union sctp_addr *src);
601         void            (*from_skb)     (union sctp_addr *,
602                                          struct sk_buff *skb,
603                                          int saddr);
604         void            (*from_sk)      (union sctp_addr *,
605                                          struct sock *sk);
606         void            (*to_sk_saddr)  (union sctp_addr *,
607                                          struct sock *sk);
608         void            (*to_sk_daddr)  (union sctp_addr *,
609                                          struct sock *sk);
610         void            (*from_addr_param) (union sctp_addr *,
611                                             union sctp_addr_param *,
612                                             __be16 port, int iif);
613         int             (*to_addr_param) (const union sctp_addr *,
614                                           union sctp_addr_param *); 
615         int             (*addr_valid)   (union sctp_addr *,
616                                          struct sctp_sock *,
617                                          const struct sk_buff *);
618         sctp_scope_t    (*scope) (union sctp_addr *);
619         void            (*inaddr_any)   (union sctp_addr *, __be16);
620         int             (*is_any)       (const union sctp_addr *);
621         int             (*available)    (union sctp_addr *,
622                                          struct sctp_sock *);
623         int             (*skb_iif)      (const struct sk_buff *sk);
624         int             (*is_ce)        (const struct sk_buff *sk);
625         void            (*seq_dump_addr)(struct seq_file *seq,
626                                          union sctp_addr *addr);
627         void            (*ecn_capable)(struct sock *sk);
628         __u16           net_header_len;
629         int             sockaddr_len;
630         sa_family_t     sa_family;
631         struct list_head list;
632 };
633 
634 struct sctp_af *sctp_get_af_specific(sa_family_t);
635 int sctp_register_af(struct sctp_af *);
636 
637 /* Protocol family functions. */
638 struct sctp_pf {
639         void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
640         void (*skb_msgname)  (struct sk_buff *, char *, int *);
641         int  (*af_supported) (sa_family_t, struct sctp_sock *);
642         int  (*cmp_addr) (const union sctp_addr *,
643                           const union sctp_addr *,
644                           struct sctp_sock *);
645         int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
646         int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
647         int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
648         struct sock *(*create_accept_sk) (struct sock *sk,
649                                           struct sctp_association *asoc);
650         void (*addr_v4map) (struct sctp_sock *, union sctp_addr *);
651         struct sctp_af *af;
652 };
653 
654 
655 /* Structure to track chunk fragments that have been acked, but peer
656  * fragments of the same message have not.
657  */
658 struct sctp_datamsg {
659         /* Chunks waiting to be submitted to lower layer. */
660         struct list_head chunks;
661         /* Reference counting. */
662         atomic_t refcnt;
663         /* When is this message no longer interesting to the peer? */
664         unsigned long expires_at;
665         /* Did the messenge fail to send? */
666         int send_error;
667         u8 send_failed:1,
668            can_abandon:1,   /* can chunks from this message can be abandoned. */
669            can_delay;       /* should this message be Nagle delayed */
670 };
671 
672 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
673                                             struct sctp_sndrcvinfo *,
674                                             struct msghdr *, int len);
675 void sctp_datamsg_free(struct sctp_datamsg *);
676 void sctp_datamsg_put(struct sctp_datamsg *);
677 void sctp_chunk_fail(struct sctp_chunk *, int error);
678 int sctp_chunk_abandoned(struct sctp_chunk *);
679 
680 /* RFC2960 1.4 Key Terms
681  *
682  * o Chunk: A unit of information within an SCTP packet, consisting of
683  * a chunk header and chunk-specific content.
684  *
685  * As a matter of convenience, we remember the SCTP common header for
686  * each chunk as well as a few other header pointers...
687  */
688 struct sctp_chunk {
689         struct list_head list;
690 
691         atomic_t refcnt;
692 
693         /* This is our link to the per-transport transmitted list.  */
694         struct list_head transmitted_list;
695 
696         /* This field is used by chunks that hold fragmented data.
697          * For the first fragment this is the list that holds the rest of
698          * fragments. For the remaining fragments, this is the link to the
699          * frag_list maintained in the first fragment.
700          */
701         struct list_head frag_list;
702 
703         /* This points to the sk_buff containing the actual data.  */
704         struct sk_buff *skb;
705 
706         /* These are the SCTP headers by reverse order in a packet.
707          * Note that some of these may happen more than once.  In that
708          * case, we point at the "current" one, whatever that means
709          * for that level of header.
710          */
711 
712         /* We point this at the FIRST TLV parameter to chunk_hdr.  */
713         union sctp_params param_hdr;
714         union {
715                 __u8 *v;
716                 struct sctp_datahdr *data_hdr;
717                 struct sctp_inithdr *init_hdr;
718                 struct sctp_sackhdr *sack_hdr;
719                 struct sctp_heartbeathdr *hb_hdr;
720                 struct sctp_sender_hb_info *hbs_hdr;
721                 struct sctp_shutdownhdr *shutdown_hdr;
722                 struct sctp_signed_cookie *cookie_hdr;
723                 struct sctp_ecnehdr *ecne_hdr;
724                 struct sctp_cwrhdr *ecn_cwr_hdr;
725                 struct sctp_errhdr *err_hdr;
726                 struct sctp_addiphdr *addip_hdr;
727                 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
728                 struct sctp_authhdr *auth_hdr;
729         } subh;
730 
731         __u8 *chunk_end;
732 
733         struct sctp_chunkhdr *chunk_hdr;
734         struct sctphdr *sctp_hdr;
735 
736         /* This needs to be recoverable for SCTP_SEND_FAILED events. */
737         struct sctp_sndrcvinfo sinfo;
738 
739         /* Which association does this belong to?  */
740         struct sctp_association *asoc;
741 
742         /* What endpoint received this chunk? */
743         struct sctp_ep_common *rcvr;
744 
745         /* We fill this in if we are calculating RTT. */
746         unsigned long sent_at;
747 
748         /* What is the origin IP address for this chunk?  */
749         union sctp_addr source;
750         /* Destination address for this chunk. */
751         union sctp_addr dest;
752 
753         /* For outbound message, track all fragments for SEND_FAILED. */
754         struct sctp_datamsg *msg;
755 
756         /* For an inbound chunk, this tells us where it came from.
757          * For an outbound chunk, it tells us where we'd like it to
758          * go.  It is NULL if we have no preference.
759          */
760         struct sctp_transport *transport;
761 
762         /* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
763          * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
764          * spec violates the principle premis that all chunks are processed
765          * in order.
766          */
767         struct sk_buff *auth_chunk;
768 
769 #define SCTP_CAN_FRTX 0x0
770 #define SCTP_NEED_FRTX 0x1
771 #define SCTP_DONT_FRTX 0x2
772         __u16   rtt_in_progress:1,      /* This chunk used for RTT calc? */
773                 has_tsn:1,              /* Does this chunk have a TSN yet? */
774                 has_ssn:1,              /* Does this chunk have a SSN yet? */
775                 singleton:1,            /* Only chunk in the packet? */
776                 end_of_packet:1,        /* Last chunk in the packet? */
777                 ecn_ce_done:1,          /* Have we processed the ECN CE bit? */
778                 pdiscard:1,             /* Discard the whole packet now? */
779                 tsn_gap_acked:1,        /* Is this chunk acked by a GAP ACK? */
780                 data_accepted:1,        /* At least 1 chunk accepted */
781                 auth:1,                 /* IN: was auth'ed | OUT: needs auth */
782                 has_asconf:1,           /* IN: have seen an asconf before */
783                 tsn_missing_report:2,   /* Data chunk missing counter. */
784                 fast_retransmit:2;      /* Is this chunk fast retransmitted? */
785 };
786 
787 void sctp_chunk_hold(struct sctp_chunk *);
788 void sctp_chunk_put(struct sctp_chunk *);
789 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
790                           struct iovec *data);
791 void sctp_chunk_free(struct sctp_chunk *);
792 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
793 void  *sctp_addto_chunk_fixed(struct sctp_chunk *, int len, const void *data);
794 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
795                                  const struct sctp_association *,
796                                  struct sock *);
797 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
798                      union sctp_addr *);
799 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
800 
801 enum {
802         SCTP_ADDR_NEW,          /* new address added to assoc/ep */
803         SCTP_ADDR_SRC,          /* address can be used as source */
804         SCTP_ADDR_DEL,          /* address about to be deleted */
805 };
806 
807 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
808 struct sctp_sockaddr_entry {
809         struct list_head list;
810         struct rcu_head rcu;
811         union sctp_addr a;
812         __u8 state;
813         __u8 valid;
814 };
815 
816 #define SCTP_ADDRESS_TICK_DELAY 500
817 
818 typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);
819 
820 /* This structure holds lists of chunks as we are assembling for
821  * transmission.
822  */
823 struct sctp_packet {
824         /* These are the SCTP header values (host order) for the packet. */
825         __u16 source_port;
826         __u16 destination_port;
827         __u32 vtag;
828 
829         /* This contains the payload chunks.  */
830         struct list_head chunk_list;
831 
832         /* This is the overhead of the sctp and ip headers. */
833         size_t overhead;
834         /* This is the total size of all chunks INCLUDING padding.  */
835         size_t size;
836 
837         /* The packet is destined for this transport address.
838          * The function we finally use to pass down to the next lower
839          * layer lives in the transport structure.
840          */
841         struct sctp_transport *transport;
842 
843         /* pointer to the auth chunk for this packet */
844         struct sctp_chunk *auth;
845 
846         u8  has_cookie_echo:1,  /* This packet contains a COOKIE-ECHO chunk. */
847             has_sack:1,         /* This packet contains a SACK chunk. */
848             has_auth:1,         /* This packet contains an AUTH chunk */
849             has_data:1,         /* This packet contains at least 1 DATA chunk */
850             ipfragok:1,         /* So let ip fragment this packet */
851             malloced:1;         /* Is it malloced? */
852 };
853 
854 struct sctp_packet *sctp_packet_init(struct sctp_packet *,
855                                      struct sctp_transport *,
856                                      __u16 sport, __u16 dport);
857 struct sctp_packet *sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
858 sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *,
859                                        struct sctp_chunk *, int);
860 sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *,
861                                      struct sctp_chunk *);
862 int sctp_packet_transmit(struct sctp_packet *);
863 void sctp_packet_free(struct sctp_packet *);
864 
865 static inline int sctp_packet_empty(struct sctp_packet *packet)
866 {
867         return packet->size == packet->overhead;
868 }
869 
870 /* This represents a remote transport address.
871  * For local transport addresses, we just use union sctp_addr.
872  *
873  * RFC2960 Section 1.4 Key Terms
874  *
875  *   o  Transport address:  A Transport Address is traditionally defined
876  *      by Network Layer address, Transport Layer protocol and Transport
877  *      Layer port number.  In the case of SCTP running over IP, a
878  *      transport address is defined by the combination of an IP address
879  *      and an SCTP port number (where SCTP is the Transport protocol).
880  *
881  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
882  *
883  *   o  The sender keeps a separate congestion control parameter set for
884  *      each of the destination addresses it can send to (not each
885  *      source-destination pair but for each destination).  The parameters
886  *      should decay if the address is not used for a long enough time
887  *      period.
888  *
889  */
890 struct sctp_transport {
891         /* A list of transports. */
892         struct list_head transports;
893 
894         /* Reference counting. */
895         atomic_t refcnt;
896         __u32    dead:1,
897                 /* RTO-Pending : A flag used to track if one of the DATA
898                  *              chunks sent to this address is currently being
899                  *              used to compute a RTT. If this flag is 0,
900                  *              the next DATA chunk sent to this destination
901                  *              should be used to compute a RTT and this flag
902                  *              should be set. Every time the RTT
903                  *              calculation completes (i.e. the DATA chunk
904                  *              is SACK'd) clear this flag.
905                  */
906                  rto_pending:1,
907 
908                 /*
909                  * hb_sent : a flag that signals that we have a pending
910                  * heartbeat.
911                  */
912                 hb_sent:1,
913 
914                 /* Is the Path MTU update pending on this tranport */
915                 pmtu_pending:1,
916 
917                 /* Is this structure kfree()able? */
918                 malloced:1;
919 
920         struct flowi fl;
921 
922         /* This is the peer's IP address and port. */
923         union sctp_addr ipaddr;
924 
925         /* These are the functions we call to handle LLP stuff.  */
926         struct sctp_af *af_specific;
927 
928         /* Which association do we belong to?  */
929         struct sctp_association *asoc;
930 
931         /* RFC2960
932          *
933          * 12.3 Per Transport Address Data
934          *
935          * For each destination transport address in the peer's
936          * address list derived from the INIT or INIT ACK chunk, a
937          * number of data elements needs to be maintained including:
938          */
939         /* RTO         : The current retransmission timeout value.  */
940         unsigned long rto;
941 
942         __u32 rtt;              /* This is the most recent RTT.  */
943 
944         /* RTTVAR      : The current RTT variation.  */
945         __u32 rttvar;
946 
947         /* SRTT        : The current smoothed round trip time.  */
948         __u32 srtt;
949 
950         /*
951          * These are the congestion stats.
952          */
953         /* cwnd        : The current congestion window.  */
954         __u32 cwnd;               /* This is the actual cwnd.  */
955 
956         /* ssthresh    : The current slow start threshold value.  */
957         __u32 ssthresh;
958 
959         /* partial     : The tracking method for increase of cwnd when in
960          * bytes acked : congestion avoidance mode (see Section 6.2.2)
961          */
962         __u32 partial_bytes_acked;
963 
964         /* Data that has been sent, but not acknowledged. */
965         __u32 flight_size;
966 
967         __u32 burst_limited;    /* Holds old cwnd when max.burst is applied */
968 
969         /* Destination */
970         struct dst_entry *dst;
971         /* Source address. */
972         union sctp_addr saddr;
973 
974         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
975          * the destination address every heartbeat interval.
976          */
977         unsigned long hbinterval;
978 
979         /* SACK delay timeout */
980         unsigned long sackdelay;
981         __u32 sackfreq;
982 
983         /* When was the last time (in jiffies) that we heard from this
984          * transport?  We use this to pick new active and retran paths.
985          */
986         unsigned long last_time_heard;
987 
988         /* Last time(in jiffies) when cwnd is reduced due to the congestion
989          * indication based on ECNE chunk.
990          */
991         unsigned long last_time_ecne_reduced;
992 
993         /* This is the max_retrans value for the transport and will
994          * be initialized from the assocs value.  This can be changed
995          * using SCTP_SET_PEER_ADDR_PARAMS socket option.
996          */
997         __u16 pathmaxrxt;
998 
999         /* PMTU       : The current known path MTU.  */
1000         __u32 pathmtu;
1001 
1002         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1003         __u32 param_flags;
1004 
1005         /* The number of times INIT has been sent on this transport. */
1006         int init_sent_count;
1007 
1008         /* state       : The current state of this destination,
1009          *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
1010          */
1011         int state;
1012 
1013         /* These are the error stats for this destination.  */
1014 
1015         /* Error count : The current error count for this destination.  */
1016         unsigned short error_count;
1017 
1018         /* Per         : A timer used by each destination.
1019          * Destination :
1020          * Timer       :
1021          *
1022          * [Everywhere else in the text this is called T3-rtx. -ed]
1023          */
1024         struct timer_list T3_rtx_timer;
1025 
1026         /* Heartbeat timer is per destination. */
1027         struct timer_list hb_timer;
1028 
1029         /* Timer to handle ICMP proto unreachable envets */
1030         struct timer_list proto_unreach_timer;
1031 
1032         /* Since we're using per-destination retransmission timers
1033          * (see above), we're also using per-destination "transmitted"
1034          * queues.  This probably ought to be a private struct
1035          * accessible only within the outqueue, but it's not, yet.
1036          */
1037         struct list_head transmitted;
1038 
1039         /* We build bundle-able packets for this transport here.  */
1040         struct sctp_packet packet;
1041 
1042         /* This is the list of transports that have chunks to send.  */
1043         struct list_head send_ready;
1044 
1045         /* State information saved for SFR_CACC algorithm. The key
1046          * idea in SFR_CACC is to maintain state at the sender on a
1047          * per-destination basis when a changeover happens.
1048          *      char changeover_active;
1049          *      char cycling_changeover;
1050          *      __u32 next_tsn_at_change;
1051          *      char cacc_saw_newack;
1052          */
1053         struct {
1054                 /* An unsigned integer, which stores the next TSN to be
1055                  * used by the sender, at the moment of changeover.
1056                  */
1057                 __u32 next_tsn_at_change;
1058 
1059                 /* A flag which indicates the occurrence of a changeover */
1060                 char changeover_active;
1061 
1062                 /* A flag which indicates whether the change of primary is
1063                  * the first switch to this destination address during an
1064                  * active switch.
1065                  */
1066                 char cycling_changeover;
1067 
1068                 /* A temporary flag, which is used during the processing of
1069                  * a SACK to estimate the causative TSN(s)'s group.
1070                  */
1071                 char cacc_saw_newack;
1072         } cacc;
1073 
1074         /* 64-bit random number sent with heartbeat. */
1075         __u64 hb_nonce;
1076 };
1077 
1078 struct sctp_transport *sctp_transport_new(const union sctp_addr *,
1079                                           gfp_t);
1080 void sctp_transport_set_owner(struct sctp_transport *,
1081                               struct sctp_association *);
1082 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1083                           struct sctp_sock *);
1084 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
1085 void sctp_transport_free(struct sctp_transport *);
1086 void sctp_transport_reset_timers(struct sctp_transport *);
1087 void sctp_transport_hold(struct sctp_transport *);
1088 void sctp_transport_put(struct sctp_transport *);
1089 void sctp_transport_update_rto(struct sctp_transport *, __u32);
1090 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1091 void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
1092 void sctp_transport_burst_limited(struct sctp_transport *);
1093 void sctp_transport_burst_reset(struct sctp_transport *);
1094 unsigned long sctp_transport_timeout(struct sctp_transport *);
1095 void sctp_transport_reset(struct sctp_transport *);
1096 void sctp_transport_update_pmtu(struct sctp_transport *, u32);
1097 void sctp_transport_immediate_rtx(struct sctp_transport *);
1098 
1099 
1100 /* This is the structure we use to queue packets as they come into
1101  * SCTP.  We write packets to it and read chunks from it.
1102  */
1103 struct sctp_inq {
1104         /* This is actually a queue of sctp_chunk each
1105          * containing a partially decoded packet.
1106          */
1107         struct list_head in_chunk_list;
1108         /* This is the packet which is currently off the in queue and is
1109          * being worked on through the inbound chunk processing.
1110          */
1111         struct sctp_chunk *in_progress;
1112 
1113         /* This is the delayed task to finish delivering inbound
1114          * messages.
1115          */
1116         struct work_struct immediate;
1117 
1118         int malloced;        /* Is this structure kfree()able?  */
1119 };
1120 
1121 void sctp_inq_init(struct sctp_inq *);
1122 void sctp_inq_free(struct sctp_inq *);
1123 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1124 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1125 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1126 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1127 
1128 /* This is the structure we use to hold outbound chunks.  You push
1129  * chunks in and they automatically pop out the other end as bundled
1130  * packets (it calls (*output_handler)()).
1131  *
1132  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1133  * and 8.2 of the v13 draft.
1134  *
1135  * It handles retransmissions.  The connection to the timeout portion
1136  * of the state machine is through sctp_..._timeout() and timeout_handler.
1137  *
1138  * If you feed it SACKs, it will eat them.
1139  *
1140  * If you give it big chunks, it will fragment them.
1141  *
1142  * It assigns TSN's to data chunks.  This happens at the last possible
1143  * instant before transmission.
1144  *
1145  * When free()'d, it empties itself out via output_handler().
1146  */
1147 struct sctp_outq {
1148         struct sctp_association *asoc;
1149 
1150         /* Data pending that has never been transmitted.  */
1151         struct list_head out_chunk_list;
1152 
1153         unsigned out_qlen;      /* Total length of queued data chunks. */
1154 
1155         /* Error of send failed, may used in SCTP_SEND_FAILED event. */
1156         unsigned error;
1157 
1158         /* These are control chunks we want to send.  */
1159         struct list_head control_chunk_list;
1160 
1161         /* These are chunks that have been sacked but are above the
1162          * CTSN, or cumulative tsn ack point.
1163          */
1164         struct list_head sacked;
1165 
1166         /* Put chunks on this list to schedule them for
1167          * retransmission.
1168          */
1169         struct list_head retransmit;
1170 
1171         /* Put chunks on this list to save them for FWD TSN processing as
1172          * they were abandoned.
1173          */
1174         struct list_head abandoned;
1175 
1176         /* How many unackd bytes do we have in-flight?  */
1177         __u32 outstanding_bytes;
1178 
1179         /* Are we doing fast-rtx on this queue */
1180         char fast_rtx;
1181 
1182         /* Corked? */
1183         char cork;
1184 
1185         /* Is this structure empty?  */
1186         char empty;
1187 
1188         /* Are we kfree()able? */
1189         char malloced;
1190 };
1191 
1192 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1193 void sctp_outq_teardown(struct sctp_outq *);
1194 void sctp_outq_free(struct sctp_outq*);
1195 int sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk);
1196 int sctp_outq_sack(struct sctp_outq *, struct sctp_sackhdr *);
1197 int sctp_outq_is_empty(const struct sctp_outq *);
1198 void sctp_outq_restart(struct sctp_outq *);
1199 
1200 void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
1201                      sctp_retransmit_reason_t);
1202 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1203 int sctp_outq_uncork(struct sctp_outq *);
1204 /* Uncork and flush an outqueue.  */
1205 static inline void sctp_outq_cork(struct sctp_outq *q)
1206 {
1207         q->cork = 1;
1208 }
1209 
1210 /* These bind address data fields common between endpoints and associations */
1211 struct sctp_bind_addr {
1212 
1213         /* RFC 2960 12.1 Parameters necessary for the SCTP instance
1214          *
1215          * SCTP Port:   The local SCTP port number the endpoint is
1216          *              bound to.
1217          */
1218         __u16 port;
1219 
1220         /* RFC 2960 12.1 Parameters necessary for the SCTP instance
1221          *
1222          * Address List: The list of IP addresses that this instance
1223          *      has bound.  This information is passed to one's
1224          *      peer(s) in INIT and INIT ACK chunks.
1225          */
1226         struct list_head address_list;
1227 
1228         int malloced;        /* Are we kfree()able?  */
1229 };
1230 
1231 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1232 void sctp_bind_addr_free(struct sctp_bind_addr *);
1233 int sctp_bind_addr_copy(struct sctp_bind_addr *dest,
1234                         const struct sctp_bind_addr *src,
1235                         sctp_scope_t scope, gfp_t gfp,
1236                         int flags);
1237 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1238                         const struct sctp_bind_addr *src,
1239                         gfp_t gfp);
1240 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1241                        __u8 addr_state, gfp_t gfp);
1242 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1243 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1244                          struct sctp_sock *);
1245 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1246                          struct sctp_sock *, struct sctp_sock *);
1247 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1248                          const union sctp_addr *addr);
1249 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr   *bp,
1250                                         const union sctp_addr   *addrs,
1251                                         int                     addrcnt,
1252                                         struct sctp_sock        *opt);
1253 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1254                                          int *addrs_len,
1255                                          gfp_t gfp);
1256 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1257                            __u16 port, gfp_t gfp);
1258 
1259 sctp_scope_t sctp_scope(const union sctp_addr *);
1260 int sctp_in_scope(const union sctp_addr *addr, const sctp_scope_t scope);
1261 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1262 int sctp_addr_is_valid(const union sctp_addr *addr);
1263 int sctp_is_ep_boundall(struct sock *sk);
1264 
1265 
1266 /* What type of endpoint?  */
1267 typedef enum {
1268         SCTP_EP_TYPE_SOCKET,
1269         SCTP_EP_TYPE_ASSOCIATION,
1270 } sctp_endpoint_type_t;
1271 
1272 /*
1273  * A common base class to bridge the implmentation view of a
1274  * socket (usually listening) endpoint versus an association's
1275  * local endpoint.
1276  * This common structure is useful for several purposes:
1277  *   1) Common interface for lookup routines.
1278  *      a) Subfunctions work for either endpoint or association
1279  *      b) Single interface to lookup allows hiding the lookup lock rather
1280  *         than acquiring it externally.
1281  *   2) Common interface for the inbound chunk handling/state machine.
1282  *   3) Common object handling routines for reference counting, etc.
1283  *   4) Disentangle association lookup from endpoint lookup, where we
1284  *      do not have to find our endpoint to find our association.
1285  *
1286  */
1287 
1288 struct sctp_ep_common {
1289         /* Fields to help us manage our entries in the hash tables. */
1290         struct hlist_node node;
1291         int hashent;
1292 
1293         /* Runtime type information.  What kind of endpoint is this? */
1294         sctp_endpoint_type_t type;
1295 
1296         /* Some fields to help us manage this object.
1297          *   refcnt   - Reference count access to this object.
1298          *   dead     - Do not attempt to use this object.
1299          *   malloced - Do we need to kfree this object?
1300          */
1301         atomic_t    refcnt;
1302         char        dead;
1303         char        malloced;
1304 
1305         /* What socket does this endpoint belong to?  */
1306         struct sock *sk;
1307 
1308         /* This is where we receive inbound chunks.  */
1309         struct sctp_inq   inqueue;
1310 
1311         /* This substructure includes the defining parameters of the
1312          * endpoint:
1313          * bind_addr.port is our shared port number.
1314          * bind_addr.address_list is our set of local IP addresses.
1315          */
1316         struct sctp_bind_addr bind_addr;
1317 };
1318 
1319 
1320 /* RFC Section 1.4 Key Terms
1321  *
1322  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1323  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1324  *   combination of a set of eligible destination transport addresses to
1325  *   which SCTP packets can be sent and a set of eligible source
1326  *   transport addresses from which SCTP packets can be received.
1327  *   All transport addresses used by an SCTP endpoint must use the
1328  *   same port number, but can use multiple IP addresses. A transport
1329  *   address used by an SCTP endpoint must not be used by another
1330  *   SCTP endpoint. In other words, a transport address is unique
1331  *   to an SCTP endpoint.
1332  *
1333  * From an implementation perspective, each socket has one of these.
1334  * A TCP-style socket will have exactly one association on one of
1335  * these.  An UDP-style socket will have multiple associations hanging
1336  * off one of these.
1337  */
1338 
1339 struct sctp_endpoint {
1340         /* Common substructure for endpoint and association. */
1341         struct sctp_ep_common base;
1342 
1343         /* Associations: A list of current associations and mappings
1344          *            to the data consumers for each association. This
1345          *            may be in the form of a hash table or other
1346          *            implementation dependent structure. The data
1347          *            consumers may be process identification
1348          *            information such as file descriptors, named pipe
1349          *            pointer, or table pointers dependent on how SCTP
1350          *            is implemented.
1351          */
1352         /* This is really a list of struct sctp_association entries. */
1353         struct list_head asocs;
1354 
1355         /* Secret Key: A secret key used by this endpoint to compute
1356          *            the MAC.  This SHOULD be a cryptographic quality
1357          *            random number with a sufficient length.
1358          *            Discussion in [RFC1750] can be helpful in
1359          *            selection of the key.
1360          */
1361         __u8 secret_key[SCTP_HOW_MANY_SECRETS][SCTP_SECRET_SIZE];
1362         int current_key;
1363         int last_key;
1364         int key_changed_at;
1365 
1366         /* digest:  This is a digest of the sctp cookie.  This field is
1367          *          only used on the receive path when we try to validate
1368          *          that the cookie has not been tampered with.  We put
1369          *          this here so we pre-allocate this once and can re-use
1370          *          on every receive.
1371          */
1372         __u8 *digest;
1373  
1374         /* sendbuf acct. policy.        */
1375         __u32 sndbuf_policy;
1376 
1377         /* rcvbuf acct. policy. */
1378         __u32 rcvbuf_policy;
1379 
1380         /* SCTP AUTH: array of the HMACs that will be allocated
1381          * we need this per association so that we don't serialize
1382          */
1383         struct crypto_hash **auth_hmacs;
1384 
1385         /* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1386          struct sctp_hmac_algo_param *auth_hmacs_list;
1387 
1388         /* SCTP-AUTH: chunks to authenticate encoded into parameter */
1389         struct sctp_chunks_param *auth_chunk_list;
1390 
1391         /* SCTP-AUTH: endpoint shared keys */
1392         struct list_head endpoint_shared_keys;
1393         __u16 active_key_id;
1394 };
1395 
1396 /* Recover the outter endpoint structure. */
1397 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1398 {
1399         struct sctp_endpoint *ep;
1400 
1401         ep = container_of(base, struct sctp_endpoint, base);
1402         return ep;
1403 }
1404 
1405 /* These are function signatures for manipulating endpoints.  */
1406 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1407 void sctp_endpoint_free(struct sctp_endpoint *);
1408 void sctp_endpoint_put(struct sctp_endpoint *);
1409 void sctp_endpoint_hold(struct sctp_endpoint *);
1410 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1411 struct sctp_association *sctp_endpoint_lookup_assoc(
1412         const struct sctp_endpoint *ep,
1413         const union sctp_addr *paddr,
1414         struct sctp_transport **);
1415 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1416                                 const union sctp_addr *);
1417 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1418                                         const union sctp_addr *);
1419 int sctp_has_association(const union sctp_addr *laddr,
1420                          const union sctp_addr *paddr);
1421 
1422 int sctp_verify_init(const struct sctp_association *asoc, sctp_cid_t,
1423                      sctp_init_chunk_t *peer_init, struct sctp_chunk *chunk,
1424                      struct sctp_chunk **err_chunk);
1425 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1426                       const union sctp_addr *peer,
1427                       sctp_init_chunk_t *init, gfp_t gfp);
1428 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1429 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1430 
1431 struct sctp_inithdr_host {
1432         __u32 init_tag;
1433         __u32 a_rwnd;
1434         __u16 num_outbound_streams;
1435         __u16 num_inbound_streams;
1436         __u32 initial_tsn;
1437 };
1438 
1439 /* RFC2960
1440  *
1441  * 12. Recommended Transmission Control Block (TCB) Parameters
1442  *
1443  * This section details a recommended set of parameters that should
1444  * be contained within the TCB for an implementation. This section is
1445  * for illustrative purposes and should not be deemed as requirements
1446  * on an implementation or as an exhaustive list of all parameters
1447  * inside an SCTP TCB. Each implementation may need its own additional
1448  * parameters for optimization.
1449  */
1450 
1451 
1452 /* Here we have information about each individual association. */
1453 struct sctp_association {
1454 
1455         /* A base structure common to endpoint and association.
1456          * In this context, it represents the associations's view
1457          * of the local endpoint of the association.
1458          */
1459         struct sctp_ep_common base;
1460 
1461         /* Associations on the same socket. */
1462         struct list_head asocs;
1463 
1464         /* association id. */
1465         sctp_assoc_t assoc_id;
1466 
1467         /* This is our parent endpoint.  */
1468         struct sctp_endpoint *ep;
1469 
1470         /* These are those association elements needed in the cookie.  */
1471         struct sctp_cookie c;
1472 
1473         /* This is all information about our peer.  */
1474         struct {
1475                 /* rwnd
1476                  *
1477                  * Peer Rwnd   : Current calculated value of the peer's rwnd.
1478                  */
1479                 __u32 rwnd;
1480 
1481                 /* transport_addr_list
1482                  *
1483                  * Peer        : A list of SCTP transport addresses that the
1484                  * Transport   : peer is bound to. This information is derived
1485                  * Address     : from the INIT or INIT ACK and is used to
1486                  * List        : associate an inbound packet with a given
1487                  *             : association. Normally this information is
1488                  *             : hashed or keyed for quick lookup and access
1489                  *             : of the TCB.
1490                  *             : The list is also initialized with the list
1491                  *             : of addresses passed with the sctp_connectx()
1492                  *             : call.
1493                  *
1494                  * It is a list of SCTP_transport's.
1495                  */
1496                 struct list_head transport_addr_list;
1497 
1498                 /* transport_count
1499                  *
1500                  * Peer        : A count of the number of peer addresses
1501                  * Transport   : in the Peer Transport Address List.
1502                  * Address     :
1503                  * Count       :
1504                  */
1505                 __u16 transport_count;
1506 
1507                 /* port
1508                  *   The transport layer port number.
1509                  */
1510                 __u16 port;
1511 
1512                 /* primary_path
1513                  *
1514                  * Primary     : This is the current primary destination
1515                  * Path        : transport address of the peer endpoint.  It
1516                  *             : may also specify a source transport address
1517                  *             : on this endpoint.
1518                  *
1519                  * All of these paths live on transport_addr_list.
1520                  *
1521                  * At the bakeoffs, we discovered that the intent of
1522                  * primaryPath is that it only changes when the ULP
1523                  * asks to have it changed.  We add the activePath to
1524                  * designate the connection we are currently using to
1525                  * transmit new data and most control chunks.
1526                  */
1527                 struct sctp_transport *primary_path;
1528 
1529                 /* Cache the primary path address here, when we
1530                  * need a an address for msg_name.
1531                  */
1532                 union sctp_addr primary_addr;
1533 
1534                 /* active_path
1535                  *   The path that we are currently using to
1536                  *   transmit new data and most control chunks.
1537                  */
1538                 struct sctp_transport *active_path;
1539 
1540                 /* retran_path
1541                  *
1542                  * RFC2960 6.4 Multi-homed SCTP Endpoints
1543                  * ...
1544                  * Furthermore, when its peer is multi-homed, an
1545                  * endpoint SHOULD try to retransmit a chunk to an
1546                  * active destination transport address that is
1547                  * different from the last destination address to
1548                  * which the DATA chunk was sent.
1549                  */
1550                 struct sctp_transport *retran_path;
1551 
1552                 /* Pointer to last transport I have sent on.  */
1553                 struct sctp_transport *last_sent_to;
1554 
1555                 /* This is the last transport I have received DATA on.  */
1556                 struct sctp_transport *last_data_from;
1557 
1558                 /*
1559                  * Mapping  An array of bits or bytes indicating which out of
1560                  * Array    order TSN's have been received (relative to the
1561                  *          Last Rcvd TSN). If no gaps exist, i.e. no out of
1562                  *          order packets have been received, this array
1563                  *          will be set to all zero. This structure may be
1564                  *          in the form of a circular buffer or bit array.
1565                  *
1566                  * Last Rcvd   : This is the last TSN received in
1567                  * TSN         : sequence. This value is set initially by
1568                  *             : taking the peer's Initial TSN, received in
1569                  *             : the INIT or INIT ACK chunk, and subtracting
1570                  *             : one from it.
1571                  *
1572                  * Throughout most of the specification this is called the
1573                  * "Cumulative TSN ACK Point".  In this case, we
1574                  * ignore the advice in 12.2 in favour of the term
1575                  * used in the bulk of the text.  This value is hidden
1576                  * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1577                  */
1578                 struct sctp_tsnmap tsn_map;
1579 
1580                 /* Ack State   : This flag indicates if the next received
1581                  *             : packet is to be responded to with a
1582                  *             : SACK. This is initializedto 0.  When a packet
1583                  *             : is received it is incremented. If this value
1584                  *             : reaches 2 or more, a SACK is sent and the
1585                  *             : value is reset to 0. Note: This is used only
1586                  *             : when no DATA chunks are received out of
1587                  *             : order.  When DATA chunks are out of order,
1588                  *             : SACK's are not delayed (see Section 6).
1589                  */
1590                 __u8    sack_needed:1,     /* Do we need to sack the peer? */
1591                         zero_window_announced:1;
1592                 __u32   sack_cnt;
1593 
1594                 /* These are capabilities which our peer advertised.  */
1595                 __u8    ecn_capable:1,      /* Can peer do ECN? */
1596                         ipv4_address:1,     /* Peer understands IPv4 addresses? */
1597                         ipv6_address:1,     /* Peer understands IPv6 addresses? */
1598                         hostname_address:1, /* Peer understands DNS addresses? */
1599                         asconf_capable:1,   /* Does peer support ADDIP? */
1600                         prsctp_capable:1,   /* Can peer do PR-SCTP? */
1601                         auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1602 
1603                 __u32   adaptation_ind;  /* Adaptation Code point. */
1604 
1605                 /* This mask is used to disable sending the ASCONF chunk
1606                  * with specified parameter to peer.
1607                  */
1608                 __be16 addip_disabled_mask;
1609 
1610                 struct sctp_inithdr_host i;
1611                 int cookie_len;
1612                 void *cookie;
1613 
1614                 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1615                  * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1616                  * Initial TSN Value minus 1
1617                  */
1618                 __u32 addip_serial;
1619 
1620                 /* SCTP-AUTH: We need to know pears random number, hmac list
1621                  * and authenticated chunk list.  All that is part of the
1622                  * cookie and these are just pointers to those locations
1623                  */
1624                 sctp_random_param_t *peer_random;
1625                 sctp_chunks_param_t *peer_chunks;
1626                 sctp_hmac_algo_param_t *peer_hmacs;
1627         } peer;
1628 
1629         /* State       : A state variable indicating what state the
1630          *             : association is in, i.e. COOKIE-WAIT,
1631          *             : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1632          *             : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1633          *
1634          *              Note: No "CLOSED" state is illustrated since if a
1635          *              association is "CLOSED" its TCB SHOULD be removed.
1636          *
1637          *              In this implementation we DO have a CLOSED
1638          *              state which is used during initiation and shutdown.
1639          *
1640          *              State takes values from SCTP_STATE_*.
1641          */
1642         sctp_state_t state;
1643 
1644         /* The cookie life I award for any cookie.  */
1645         struct timeval cookie_life;
1646 
1647         /* Overall     : The overall association error count.
1648          * Error Count : [Clear this any time I get something.]
1649          */
1650         int overall_error_count;
1651 
1652         /* These are the association's initial, max, and min RTO values.
1653          * These values will be initialized by system defaults, but can
1654          * be modified via the SCTP_RTOINFO socket option.
1655          */
1656         unsigned long rto_initial;
1657         unsigned long rto_max;
1658         unsigned long rto_min;
1659 
1660         /* Maximum number of new data packets that can be sent in a burst.  */
1661         int max_burst;
1662 
1663         /* This is the max_retrans value for the association.  This value will
1664          * be initialized initialized from system defaults, but can be
1665          * modified by the SCTP_ASSOCINFO socket option.
1666          */
1667         int max_retrans;
1668 
1669         /* Maximum number of times the endpoint will retransmit INIT  */
1670         __u16 max_init_attempts;
1671 
1672         /* How many times have we resent an INIT? */
1673         __u16 init_retries;
1674 
1675         /* The largest timeout or RTO value to use in attempting an INIT */
1676         unsigned long max_init_timeo;
1677 
1678         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1679          * the destination address every heartbeat interval. This value
1680          * will be inherited by all new transports.
1681          */
1682         unsigned long hbinterval;
1683 
1684         /* This is the max_retrans value for new transports in the
1685          * association.
1686          */
1687         __u16 pathmaxrxt;
1688 
1689         /* Flag that path mtu update is pending */
1690         __u8   pmtu_pending;
1691 
1692         /* Association : The smallest PMTU discovered for all of the
1693          * PMTU        : peer's transport addresses.
1694          */
1695         __u32 pathmtu;
1696 
1697         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1698         __u32 param_flags;
1699 
1700         /* SACK delay timeout */
1701         unsigned long sackdelay;
1702         __u32 sackfreq;
1703 
1704 
1705         unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1706         struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1707 
1708         /* Transport to which SHUTDOWN chunk was last sent.  */
1709         struct sctp_transport *shutdown_last_sent_to;
1710 
1711         /* How many times have we resent a SHUTDOWN */
1712         int shutdown_retries;
1713 
1714         /* Transport to which INIT chunk was last sent.  */
1715         struct sctp_transport *init_last_sent_to;
1716 
1717         /* Next TSN    : The next TSN number to be assigned to a new
1718          *             : DATA chunk.  This is sent in the INIT or INIT
1719          *             : ACK chunk to the peer and incremented each
1720          *             : time a DATA chunk is assigned a TSN
1721          *             : (normally just prior to transmit or during
1722          *             : fragmentation).
1723          */
1724         __u32 next_tsn;
1725 
1726         /*
1727          * Last Rcvd   : This is the last TSN received in sequence.  This value
1728          * TSN         : is set initially by taking the peer's Initial TSN,
1729          *             : received in the INIT or INIT ACK chunk, and
1730          *             : subtracting one from it.
1731          *
1732          * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1733          */
1734 
1735         __u32 ctsn_ack_point;
1736 
1737         /* PR-SCTP Advanced.Peer.Ack.Point */
1738         __u32 adv_peer_ack_point;
1739 
1740         /* Highest TSN that is acknowledged by incoming SACKs. */
1741         __u32 highest_sacked;
1742 
1743         /* TSN marking the fast recovery exit point */
1744         __u32 fast_recovery_exit;
1745 
1746         /* Flag to track the current fast recovery state */
1747         __u8 fast_recovery;
1748 
1749         /* The number of unacknowledged data chunks.  Reported through
1750          * the SCTP_STATUS sockopt.
1751          */
1752         __u16 unack_data;
1753 
1754         /* The total number of data chunks that we've had to retransmit
1755          * as the result of a T3 timer expiration
1756          */
1757         __u32 rtx_data_chunks;
1758 
1759         /* This is the association's receive buffer space.  This value is used
1760          * to set a_rwnd field in an INIT or a SACK chunk.
1761          */
1762         __u32 rwnd;
1763 
1764         /* This is the last advertised value of rwnd over a SACK chunk. */
1765         __u32 a_rwnd;
1766 
1767         /* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1768          * to slop over a maximum of the association's frag_point.
1769          */
1770         __u32 rwnd_over;
1771 
1772         /* Keeps treack of rwnd pressure.  This happens when we have
1773          * a window, but not recevie buffer (i.e small packets).  This one
1774          * is releases slowly (1 PMTU at a time ).
1775          */
1776         __u32 rwnd_press;
1777 
1778         /* This is the sndbuf size in use for the association.
1779          * This corresponds to the sndbuf size for the association,
1780          * as specified in the sk->sndbuf.
1781          */
1782         int sndbuf_used;
1783 
1784         /* This is the amount of memory that this association has allocated
1785          * in the receive path at any given time.
1786          */
1787         atomic_t rmem_alloc;
1788 
1789         /* This is the wait queue head for send requests waiting on
1790          * the association sndbuf space.
1791          */
1792         wait_queue_head_t       wait;
1793 
1794         /* The message size at which SCTP fragmentation will occur. */
1795         __u32 frag_point;
1796         __u32 user_frag;
1797 
1798         /* Counter used to count INIT errors. */
1799         int init_err_counter;
1800 
1801         /* Count the number of INIT cycles (for doubling timeout). */
1802         int init_cycle;
1803 
1804         /* Default send parameters. */
1805         __u16 default_stream;
1806         __u16 default_flags;
1807         __u32 default_ppid;
1808         __u32 default_context;
1809         __u32 default_timetolive;
1810 
1811         /* Default receive parameters */
1812         __u32 default_rcv_context;
1813 
1814         /* This tracks outbound ssn for a given stream.  */
1815         struct sctp_ssnmap *ssnmap;
1816 
1817         /* All outbound chunks go through this structure.  */
1818         struct sctp_outq outqueue;
1819 
1820         /* A smart pipe that will handle reordering and fragmentation,
1821          * as well as handle passing events up to the ULP.
1822          */
1823         struct sctp_ulpq ulpq;
1824 
1825         /* Last TSN that caused an ECNE Chunk to be sent.  */
1826         __u32 last_ecne_tsn;
1827 
1828         /* Last TSN that caused a CWR Chunk to be sent.  */
1829         __u32 last_cwr_tsn;
1830 
1831         /* How many duplicated TSNs have we seen?  */
1832         int numduptsns;
1833 
1834         /* Number of seconds of idle time before an association is closed.
1835          * In the association context, this is really used as a boolean
1836          * since the real timeout is stored in the timeouts array
1837          */
1838         __u32 autoclose;
1839 
1840         /* These are to support
1841          * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1842          *  and Enforcement of Flow and Message Limits"
1843          * <draft-ietf-tsvwg-addip-sctp-02.txt>
1844          * or "ADDIP" for short.
1845          */
1846 
1847 
1848 
1849         /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1850          *
1851          * R1) One and only one ASCONF Chunk MAY be in transit and
1852          * unacknowledged at any one time.  If a sender, after sending
1853          * an ASCONF chunk, decides it needs to transfer another
1854          * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1855          * returns from the previous ASCONF Chunk before sending a
1856          * subsequent ASCONF. Note this restriction binds each side,
1857          * so at any time two ASCONF may be in-transit on any given
1858          * association (one sent from each endpoint).
1859          *
1860          * [This is our one-and-only-one ASCONF in flight.  If we do
1861          * not have an ASCONF in flight, this is NULL.]
1862          */
1863         struct sctp_chunk *addip_last_asconf;
1864 
1865         /* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1866          *
1867          * This is needed to implement itmes E1 - E4 of the updated
1868          * spec.  Here is the justification:
1869          *
1870          * Since the peer may bundle multiple ASCONF chunks toward us,
1871          * we now need the ability to cache multiple ACKs.  The section
1872          * describes in detail how they are cached and cleaned up.
1873          */
1874         struct list_head asconf_ack_list;
1875 
1876         /* These ASCONF chunks are waiting to be sent.
1877          *
1878          * These chunaks can't be pushed to outqueue until receiving
1879          * ASCONF_ACK for the previous ASCONF indicated by
1880          * addip_last_asconf, so as to guarantee that only one ASCONF
1881          * is in flight at any time.
1882          *
1883          * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1884          *
1885          * In defining the ASCONF Chunk transfer procedures, it is
1886          * essential that these transfers MUST NOT cause congestion
1887          * within the network.  To achieve this, we place these
1888          * restrictions on the transfer of ASCONF Chunks:
1889          *
1890          * R1) One and only one ASCONF Chunk MAY be in transit and
1891          * unacknowledged at any one time.  If a sender, after sending
1892          * an ASCONF chunk, decides it needs to transfer another
1893          * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1894          * returns from the previous ASCONF Chunk before sending a
1895          * subsequent ASCONF. Note this restriction binds each side,
1896          * so at any time two ASCONF may be in-transit on any given
1897          * association (one sent from each endpoint).
1898          *
1899          *
1900          * [I really think this is EXACTLY the sort of intelligence
1901          *  which already resides in sctp_outq.  Please move this
1902          *  queue and its supporting logic down there.  --piggy]
1903          */
1904         struct list_head addip_chunk_list;
1905 
1906         /* ADDIP Section 4.1 ASCONF Chunk Procedures
1907          *
1908          * A2) A serial number should be assigned to the Chunk. The
1909          * serial number SHOULD be a monotonically increasing
1910          * number. The serial number SHOULD be initialized at
1911          * the start of the association to the same value as the
1912          * Initial TSN and every time a new ASCONF chunk is created
1913          * it is incremented by one after assigning the serial number
1914          * to the newly created chunk.
1915          *
1916          * ADDIP
1917          * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1918          *
1919          * Serial Number : 32 bits (unsigned integer)
1920          *
1921          * This value represents a Serial Number for the ASCONF
1922          * Chunk. The valid range of Serial Number is from 0 to
1923          * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1924          * after reaching 4294967295.
1925          */
1926         __u32 addip_serial;
1927         union sctp_addr *asconf_addr_del_pending;
1928         int src_out_of_asoc_ok;
1929         struct sctp_transport *new_transport;
1930 
1931         /* SCTP AUTH: list of the endpoint shared keys.  These
1932          * keys are provided out of band by the user applicaton
1933          * and can't change during the lifetime of the association
1934          */
1935         struct list_head endpoint_shared_keys;
1936 
1937         /* SCTP AUTH:
1938          * The current generated assocaition shared key (secret)
1939          */
1940         struct sctp_auth_bytes *asoc_shared_key;
1941 
1942         /* SCTP AUTH: hmac id of the first peer requested algorithm
1943          * that we support.
1944          */
1945         __u16 default_hmac_id;
1946 
1947         __u16 active_key_id;
1948 
1949         __u8 need_ecne:1,       /* Need to send an ECNE Chunk? */
1950              temp:1;            /* Is it a temporary association? */
1951 };
1952 
1953 
1954 /* An eyecatcher for determining if we are really looking at an
1955  * association data structure.
1956  */
1957 enum {
1958         SCTP_ASSOC_EYECATCHER = 0xa550c123,
1959 };
1960 
1961 /* Recover the outter association structure. */
1962 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1963 {
1964         struct sctp_association *asoc;
1965 
1966         asoc = container_of(base, struct sctp_association, base);
1967         return asoc;
1968 }
1969 
1970 /* These are function signatures for manipulating associations.  */
1971 
1972 
1973 struct sctp_association *
1974 sctp_association_new(const struct sctp_endpoint *, const struct sock *,
1975                      sctp_scope_t scope, gfp_t gfp);
1976 void sctp_association_free(struct sctp_association *);
1977 void sctp_association_put(struct sctp_association *);
1978 void sctp_association_hold(struct sctp_association *);
1979 
1980 struct sctp_transport *sctp_assoc_choose_alter_transport(
1981         struct sctp_association *, struct sctp_transport *);
1982 void sctp_assoc_update_retran_path(struct sctp_association *);
1983 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1984                                           const union sctp_addr *);
1985 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1986                             const union sctp_addr *laddr);
1987 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
1988                                      const union sctp_addr *address,
1989                                      const gfp_t gfp,
1990                                      const int peer_state);
1991 void sctp_assoc_del_peer(struct sctp_association *asoc,
1992                          const union sctp_addr *addr);
1993 void sctp_assoc_rm_peer(struct sctp_association *asoc,
1994                          struct sctp_transport *peer);
1995 void sctp_assoc_control_transport(struct sctp_association *,
1996                                   struct sctp_transport *,
1997                                   sctp_transport_cmd_t, sctp_sn_error_t);
1998 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
1999 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
2000                                            const union sctp_addr *,
2001                                            const union sctp_addr *);
2002 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2003 void sctp_assoc_update(struct sctp_association *old,
2004                        struct sctp_association *new);
2005 
2006 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2007 
2008 void sctp_assoc_sync_pmtu(struct sctp_association *);
2009 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned);
2010 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned);
2011 void sctp_assoc_set_primary(struct sctp_association *,
2012                             struct sctp_transport *);
2013 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2014                                     struct sctp_transport *);
2015 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
2016                                      sctp_scope_t, gfp_t);
2017 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2018                                          struct sctp_cookie*,
2019                                          gfp_t gfp);
2020 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2021 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2022 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2023                                         const struct sctp_association *asoc,
2024                                         __be32 serial);
2025 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2026 
2027 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2028                         const union sctp_addr *ss2);
2029 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2030 
2031 /* A convenience structure to parse out SCTP specific CMSGs. */
2032 typedef struct sctp_cmsgs {
2033         struct sctp_initmsg *init;
2034         struct sctp_sndrcvinfo *info;
2035 } sctp_cmsgs_t;
2036 
2037 /* Structure for tracking memory objects */
2038 typedef struct {
2039         char *label;
2040         atomic_t *counter;
2041 } sctp_dbg_objcnt_entry_t;
2042 
2043 #endif /* __sctp_structs_h__ */
2044 

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