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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, see
 23  * <http://www.gnu.org/licenses/>.
 24  *
 25  * Please send any bug reports or fixes you make to the
 26  * email addresses:
 27  *    lksctp developers <linux-sctp@vger.kernel.org>
 28  *
 29  * Written or modified by:
 30  *    Randall Stewart       <randall@sctp.chicago.il.us>
 31  *    Ken Morneau           <kmorneau@cisco.com>
 32  *    Qiaobing Xie          <qxie1@email.mot.com>
 33  *    La Monte H.P. Yarroll <piggy@acm.org>
 34  *    Karl Knutson          <karl@athena.chicago.il.us>
 35  *    Jon Grimm             <jgrimm@us.ibm.com>
 36  *    Xingang Guo           <xingang.guo@intel.com>
 37  *    Hui Huang             <hui.huang@nokia.com>
 38  *    Sridhar Samudrala     <sri@us.ibm.com>
 39  *    Daisy Chang           <daisyc@us.ibm.com>
 40  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
 41  *    Ardelle Fan           <ardelle.fan@intel.com>
 42  *    Ryan Layer            <rmlayer@us.ibm.com>
 43  *    Anup Pemmaiah         <pemmaiah@cc.usu.edu>
 44  *    Kevin Gao             <kevin.gao@intel.com>
 45  */
 46 
 47 #ifndef __sctp_structs_h__
 48 #define __sctp_structs_h__
 49 
 50 #include <linux/ktime.h>
 51 #include <linux/generic-radix-tree.h>
 52 #include <linux/rhashtable-types.h>
 53 #include <linux/socket.h>       /* linux/in.h needs this!!    */
 54 #include <linux/in.h>           /* We get struct sockaddr_in. */
 55 #include <linux/in6.h>          /* We get struct in6_addr     */
 56 #include <linux/ipv6.h>
 57 #include <asm/param.h>          /* We get MAXHOSTNAMELEN.     */
 58 #include <linux/atomic.h>               /* This gets us atomic counters.  */
 59 #include <linux/skbuff.h>       /* We need sk_buff_head. */
 60 #include <linux/workqueue.h>    /* We need tq_struct.    */
 61 #include <linux/sctp.h>         /* We need sctp* header structs.  */
 62 #include <net/sctp/auth.h>      /* We need auth specific structs */
 63 #include <net/ip.h>             /* For inet_skb_parm */
 64 
 65 /* A convenience structure for handling sockaddr structures.
 66  * We should wean ourselves off this.
 67  */
 68 union sctp_addr {
 69         struct sockaddr_in v4;
 70         struct sockaddr_in6 v6;
 71         struct sockaddr sa;
 72 };
 73 
 74 /* Forward declarations for data structures. */
 75 struct sctp_globals;
 76 struct sctp_endpoint;
 77 struct sctp_association;
 78 struct sctp_transport;
 79 struct sctp_packet;
 80 struct sctp_chunk;
 81 struct sctp_inq;
 82 struct sctp_outq;
 83 struct sctp_bind_addr;
 84 struct sctp_ulpq;
 85 struct sctp_ep_common;
 86 struct crypto_shash;
 87 struct sctp_stream;
 88 
 89 
 90 #include <net/sctp/tsnmap.h>
 91 #include <net/sctp/ulpevent.h>
 92 #include <net/sctp/ulpqueue.h>
 93 #include <net/sctp/stream_interleave.h>
 94 
 95 /* Structures useful for managing bind/connect. */
 96 
 97 struct sctp_bind_bucket {
 98         unsigned short  port;
 99         signed char     fastreuse;
100         signed char     fastreuseport;
101         kuid_t          fastuid;
102         struct hlist_node       node;
103         struct hlist_head       owner;
104         struct net      *net;
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         /* This is a list of groups of functions for each address
122          * family that we support.
123          */
124         struct list_head address_families;
125 
126         /* This is the hash of all endpoints. */
127         struct sctp_hashbucket *ep_hashtable;
128         /* This is the sctp port control hash.  */
129         struct sctp_bind_hashbucket *port_hashtable;
130         /* This is the hash of all transports. */
131         struct rhltable transport_hashtable;
132 
133         /* Sizes of above hashtables. */
134         int ep_hashsize;
135         int port_hashsize;
136 
137         /* Default initialization values to be applied to new associations. */
138         __u16 max_instreams;
139         __u16 max_outstreams;
140 
141         /* Flag to indicate whether computing and verifying checksum
142          * is disabled. */
143         bool checksum_disable;
144 } sctp_globals;
145 
146 #define sctp_max_instreams              (sctp_globals.max_instreams)
147 #define sctp_max_outstreams             (sctp_globals.max_outstreams)
148 #define sctp_address_families           (sctp_globals.address_families)
149 #define sctp_ep_hashsize                (sctp_globals.ep_hashsize)
150 #define sctp_ep_hashtable               (sctp_globals.ep_hashtable)
151 #define sctp_port_hashsize              (sctp_globals.port_hashsize)
152 #define sctp_port_hashtable             (sctp_globals.port_hashtable)
153 #define sctp_transport_hashtable        (sctp_globals.transport_hashtable)
154 #define sctp_checksum_disable           (sctp_globals.checksum_disable)
155 
156 /* SCTP Socket type: UDP or TCP style. */
157 enum sctp_socket_type {
158         SCTP_SOCKET_UDP = 0,
159         SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
160         SCTP_SOCKET_TCP
161 };
162 
163 /* Per socket SCTP information. */
164 struct sctp_sock {
165         /* inet_sock has to be the first member of sctp_sock */
166         struct inet_sock inet;
167         /* What kind of a socket is this? */
168         enum sctp_socket_type type;
169 
170         /* PF_ family specific functions.  */
171         struct sctp_pf *pf;
172 
173         /* Access to HMAC transform. */
174         struct crypto_shash *hmac;
175         char *sctp_hmac_alg;
176 
177         /* What is our base endpointer? */
178         struct sctp_endpoint *ep;
179 
180         struct sctp_bind_bucket *bind_hash;
181         /* Various Socket Options.  */
182         __u16 default_stream;
183         __u32 default_ppid;
184         __u16 default_flags;
185         __u32 default_context;
186         __u32 default_timetolive;
187         __u32 default_rcv_context;
188         int max_burst;
189 
190         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
191          * the destination address every heartbeat interval. This value
192          * will be inherited by all new associations.
193          */
194         __u32 hbinterval;
195 
196         /* This is the max_retrans value for new associations. */
197         __u16 pathmaxrxt;
198 
199         __u32 flowlabel;
200         __u8  dscp;
201 
202         int pf_retrans;
203 
204         /* The initial Path MTU to use for new associations. */
205         __u32 pathmtu;
206 
207         /* The default SACK delay timeout for new associations. */
208         __u32 sackdelay;
209         __u32 sackfreq;
210 
211         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
212         __u32 param_flags;
213 
214         __u32 default_ss;
215 
216         struct sctp_rtoinfo rtoinfo;
217         struct sctp_paddrparams paddrparam;
218         struct sctp_assocparams assocparams;
219 
220         /*
221          * These two structures must be grouped together for the usercopy
222          * whitelist region.
223          */
224         __u16 subscribe;
225         struct sctp_initmsg initmsg;
226 
227         int user_frag;
228 
229         __u32 autoclose;
230         __u32 adaptation_ind;
231         __u32 pd_point;
232         __u16   nodelay:1,
233                 reuse:1,
234                 disable_fragments:1,
235                 v4mapped:1,
236                 frag_interleave:1,
237                 strm_interleave:1,
238                 recvrcvinfo:1,
239                 recvnxtinfo:1,
240                 data_ready_signalled:1;
241 
242         atomic_t pd_mode;
243         /* Receive to here while partial delivery is in effect. */
244         struct sk_buff_head pd_lobby;
245 
246         /* These must be the last fields, as they will skipped on copies,
247          * like on accept and peeloff operations
248          */
249         struct list_head auto_asconf_list;
250         int do_auto_asconf;
251 };
252 
253 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
254 {
255        return (struct sctp_sock *)sk;
256 }
257 
258 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
259 {
260        return (struct sock *)sp;
261 }
262 
263 #if IS_ENABLED(CONFIG_IPV6)
264 struct sctp6_sock {
265        struct sctp_sock  sctp;
266        struct ipv6_pinfo inet6;
267 };
268 #endif /* CONFIG_IPV6 */
269 
270 
271 /* This is our APPLICATION-SPECIFIC state cookie.
272  * THIS IS NOT DICTATED BY THE SPECIFICATION.
273  */
274 /* These are the parts of an association which we send in the cookie.
275  * Most of these are straight out of:
276  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
277  *
278  */
279 
280 struct sctp_cookie {
281 
282         /* My          : Tag expected in every inbound packet and sent
283          * Verification: in the INIT or INIT ACK chunk.
284          * Tag         :
285          */
286         __u32 my_vtag;
287 
288         /* Peer's      : Tag expected in every outbound packet except
289          * Verification: in the INIT chunk.
290          * Tag         :
291          */
292         __u32 peer_vtag;
293 
294         /* The rest of these are not from the spec, but really need to
295          * be in the cookie.
296          */
297 
298         /* My Tie Tag  : Assist in discovering a restarting association. */
299         __u32 my_ttag;
300 
301         /* Peer's Tie Tag: Assist in discovering a restarting association. */
302         __u32 peer_ttag;
303 
304         /* When does this cookie expire? */
305         ktime_t expiration;
306 
307         /* Number of inbound/outbound streams which are set
308          * and negotiated during the INIT process.
309          */
310         __u16 sinit_num_ostreams;
311         __u16 sinit_max_instreams;
312 
313         /* This is the first sequence number I used.  */
314         __u32 initial_tsn;
315 
316         /* This holds the originating address of the INIT packet.  */
317         union sctp_addr peer_addr;
318 
319         /* IG Section 2.35.3 
320          * Include the source port of the INIT-ACK
321          */
322         __u16           my_port;
323 
324         __u8 prsctp_capable;
325 
326         /* Padding for future use */
327         __u8 padding;           
328 
329         __u32 adaptation_ind;
330 
331         __u8 auth_random[sizeof(struct sctp_paramhdr) +
332                          SCTP_AUTH_RANDOM_LENGTH];
333         __u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
334         __u8 auth_chunks[sizeof(struct sctp_paramhdr) + SCTP_AUTH_MAX_CHUNKS];
335 
336         /* This is a shim for my peer's INIT packet, followed by
337          * a copy of the raw address list of the association.
338          * The length of the raw address list is saved in the
339          * raw_addr_list_len field, which will be used at the time when
340          * the association TCB is re-constructed from the cookie.
341          */
342         __u32 raw_addr_list_len;
343         struct sctp_init_chunk peer_init[0];
344 };
345 
346 
347 /* The format of our cookie that we send to our peer. */
348 struct sctp_signed_cookie {
349         __u8 signature[SCTP_SECRET_SIZE];
350         __u32 __pad;            /* force sctp_cookie alignment to 64 bits */
351         struct sctp_cookie c;
352 } __packed;
353 
354 /* This is another convenience type to allocate memory for address
355  * params for the maximum size and pass such structures around
356  * internally.
357  */
358 union sctp_addr_param {
359         struct sctp_paramhdr p;
360         struct sctp_ipv4addr_param v4;
361         struct sctp_ipv6addr_param v6;
362 };
363 
364 /* A convenience type to allow walking through the various
365  * parameters and avoid casting all over the place.
366  */
367 union sctp_params {
368         void *v;
369         struct sctp_paramhdr *p;
370         struct sctp_cookie_preserve_param *life;
371         struct sctp_hostname_param *dns;
372         struct sctp_cookie_param *cookie;
373         struct sctp_supported_addrs_param *sat;
374         struct sctp_ipv4addr_param *v4;
375         struct sctp_ipv6addr_param *v6;
376         union sctp_addr_param *addr;
377         struct sctp_adaptation_ind_param *aind;
378         struct sctp_supported_ext_param *ext;
379         struct sctp_random_param *random;
380         struct sctp_chunks_param *chunks;
381         struct sctp_hmac_algo_param *hmac_algo;
382         struct sctp_addip_param *addip;
383 };
384 
385 /* RFC 2960.  Section 3.3.5 Heartbeat.
386  *    Heartbeat Information: variable length
387  *    The Sender-specific Heartbeat Info field should normally include
388  *    information about the sender's current time when this HEARTBEAT
389  *    chunk is sent and the destination transport address to which this
390  *    HEARTBEAT is sent (see Section 8.3).
391  */
392 struct sctp_sender_hb_info {
393         struct sctp_paramhdr param_hdr;
394         union sctp_addr daddr;
395         unsigned long sent_at;
396         __u64 hb_nonce;
397 };
398 
399 int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
400                      gfp_t gfp);
401 int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid);
402 void sctp_stream_free(struct sctp_stream *stream);
403 void sctp_stream_clear(struct sctp_stream *stream);
404 void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new);
405 
406 /* What is the current SSN number for this stream? */
407 #define sctp_ssn_peek(stream, type, sid) \
408         (sctp_stream_##type((stream), (sid))->ssn)
409 
410 /* Return the next SSN number for this stream.  */
411 #define sctp_ssn_next(stream, type, sid) \
412         (sctp_stream_##type((stream), (sid))->ssn++)
413 
414 /* Skip over this ssn and all below. */
415 #define sctp_ssn_skip(stream, type, sid, ssn) \
416         (sctp_stream_##type((stream), (sid))->ssn = ssn + 1)
417 
418 /* What is the current MID number for this stream? */
419 #define sctp_mid_peek(stream, type, sid) \
420         (sctp_stream_##type((stream), (sid))->mid)
421 
422 /* Return the next MID number for this stream.  */
423 #define sctp_mid_next(stream, type, sid) \
424         (sctp_stream_##type((stream), (sid))->mid++)
425 
426 /* Skip over this mid and all below. */
427 #define sctp_mid_skip(stream, type, sid, mid) \
428         (sctp_stream_##type((stream), (sid))->mid = mid + 1)
429 
430 /* What is the current MID_uo number for this stream? */
431 #define sctp_mid_uo_peek(stream, type, sid) \
432         (sctp_stream_##type((stream), (sid))->mid_uo)
433 
434 /* Return the next MID_uo number for this stream.  */
435 #define sctp_mid_uo_next(stream, type, sid) \
436         (sctp_stream_##type((stream), (sid))->mid_uo++)
437 
438 /*
439  * Pointers to address related SCTP functions.
440  * (i.e. things that depend on the address family.)
441  */
442 struct sctp_af {
443         int             (*sctp_xmit)    (struct sk_buff *skb,
444                                          struct sctp_transport *);
445         int             (*setsockopt)   (struct sock *sk,
446                                          int level,
447                                          int optname,
448                                          char __user *optval,
449                                          unsigned int optlen);
450         int             (*getsockopt)   (struct sock *sk,
451                                          int level,
452                                          int optname,
453                                          char __user *optval,
454                                          int __user *optlen);
455         int             (*compat_setsockopt)    (struct sock *sk,
456                                          int level,
457                                          int optname,
458                                          char __user *optval,
459                                          unsigned int optlen);
460         int             (*compat_getsockopt)    (struct sock *sk,
461                                          int level,
462                                          int optname,
463                                          char __user *optval,
464                                          int __user *optlen);
465         void            (*get_dst)      (struct sctp_transport *t,
466                                          union sctp_addr *saddr,
467                                          struct flowi *fl,
468                                          struct sock *sk);
469         void            (*get_saddr)    (struct sctp_sock *sk,
470                                          struct sctp_transport *t,
471                                          struct flowi *fl);
472         void            (*copy_addrlist) (struct list_head *,
473                                           struct net_device *);
474         int             (*cmp_addr)     (const union sctp_addr *addr1,
475                                          const union sctp_addr *addr2);
476         void            (*addr_copy)    (union sctp_addr *dst,
477                                          union sctp_addr *src);
478         void            (*from_skb)     (union sctp_addr *,
479                                          struct sk_buff *skb,
480                                          int saddr);
481         void            (*from_sk)      (union sctp_addr *,
482                                          struct sock *sk);
483         void            (*from_addr_param) (union sctp_addr *,
484                                             union sctp_addr_param *,
485                                             __be16 port, int iif);
486         int             (*to_addr_param) (const union sctp_addr *,
487                                           union sctp_addr_param *); 
488         int             (*addr_valid)   (union sctp_addr *,
489                                          struct sctp_sock *,
490                                          const struct sk_buff *);
491         enum sctp_scope (*scope)(union sctp_addr *);
492         void            (*inaddr_any)   (union sctp_addr *, __be16);
493         int             (*is_any)       (const union sctp_addr *);
494         int             (*available)    (union sctp_addr *,
495                                          struct sctp_sock *);
496         int             (*skb_iif)      (const struct sk_buff *sk);
497         int             (*is_ce)        (const struct sk_buff *sk);
498         void            (*seq_dump_addr)(struct seq_file *seq,
499                                          union sctp_addr *addr);
500         void            (*ecn_capable)(struct sock *sk);
501         __u16           net_header_len;
502         int             sockaddr_len;
503         int             (*ip_options_len)(struct sock *sk);
504         sa_family_t     sa_family;
505         struct list_head list;
506 };
507 
508 struct sctp_af *sctp_get_af_specific(sa_family_t);
509 int sctp_register_af(struct sctp_af *);
510 
511 /* Protocol family functions. */
512 struct sctp_pf {
513         void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
514         void (*skb_msgname)  (struct sk_buff *, char *, int *);
515         int  (*af_supported) (sa_family_t, struct sctp_sock *);
516         int  (*cmp_addr) (const union sctp_addr *,
517                           const union sctp_addr *,
518                           struct sctp_sock *);
519         int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
520         int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
521         int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
522         struct sock *(*create_accept_sk) (struct sock *sk,
523                                           struct sctp_association *asoc,
524                                           bool kern);
525         int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
526         void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
527         void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
528         void (*copy_ip_options)(struct sock *sk, struct sock *newsk);
529         struct sctp_af *af;
530 };
531 
532 
533 /* Structure to track chunk fragments that have been acked, but peer
534  * fragments of the same message have not.
535  */
536 struct sctp_datamsg {
537         /* Chunks waiting to be submitted to lower layer. */
538         struct list_head chunks;
539         /* Reference counting. */
540         refcount_t refcnt;
541         /* When is this message no longer interesting to the peer? */
542         unsigned long expires_at;
543         /* Did the messenge fail to send? */
544         int send_error;
545         u8 send_failed:1,
546            can_delay:1, /* should this message be Nagle delayed */
547            abandoned:1; /* should this message be abandoned */
548 };
549 
550 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
551                                             struct sctp_sndrcvinfo *,
552                                             struct iov_iter *);
553 void sctp_datamsg_free(struct sctp_datamsg *);
554 void sctp_datamsg_put(struct sctp_datamsg *);
555 void sctp_chunk_fail(struct sctp_chunk *, int error);
556 int sctp_chunk_abandoned(struct sctp_chunk *);
557 
558 /* RFC2960 1.4 Key Terms
559  *
560  * o Chunk: A unit of information within an SCTP packet, consisting of
561  * a chunk header and chunk-specific content.
562  *
563  * As a matter of convenience, we remember the SCTP common header for
564  * each chunk as well as a few other header pointers...
565  */
566 struct sctp_chunk {
567         struct list_head list;
568 
569         refcount_t refcnt;
570 
571         /* How many times this chunk have been sent, for prsctp RTX policy */
572         int sent_count;
573 
574         union {
575                 /* This is our link to the per-transport transmitted list.  */
576                 struct list_head transmitted_list;
577                 /* List in specific stream outq */
578                 struct list_head stream_list;
579         };
580 
581         /* This field is used by chunks that hold fragmented data.
582          * For the first fragment this is the list that holds the rest of
583          * fragments. For the remaining fragments, this is the link to the
584          * frag_list maintained in the first fragment.
585          */
586         struct list_head frag_list;
587 
588         /* This points to the sk_buff containing the actual data.  */
589         struct sk_buff *skb;
590 
591         union {
592                 /* In case of GSO packets, this will store the head one */
593                 struct sk_buff *head_skb;
594                 /* In case of auth enabled, this will point to the shkey */
595                 struct sctp_shared_key *shkey;
596         };
597 
598         /* These are the SCTP headers by reverse order in a packet.
599          * Note that some of these may happen more than once.  In that
600          * case, we point at the "current" one, whatever that means
601          * for that level of header.
602          */
603 
604         /* We point this at the FIRST TLV parameter to chunk_hdr.  */
605         union sctp_params param_hdr;
606         union {
607                 __u8 *v;
608                 struct sctp_datahdr *data_hdr;
609                 struct sctp_inithdr *init_hdr;
610                 struct sctp_sackhdr *sack_hdr;
611                 struct sctp_heartbeathdr *hb_hdr;
612                 struct sctp_sender_hb_info *hbs_hdr;
613                 struct sctp_shutdownhdr *shutdown_hdr;
614                 struct sctp_signed_cookie *cookie_hdr;
615                 struct sctp_ecnehdr *ecne_hdr;
616                 struct sctp_cwrhdr *ecn_cwr_hdr;
617                 struct sctp_errhdr *err_hdr;
618                 struct sctp_addiphdr *addip_hdr;
619                 struct sctp_fwdtsn_hdr *fwdtsn_hdr;
620                 struct sctp_authhdr *auth_hdr;
621                 struct sctp_idatahdr *idata_hdr;
622                 struct sctp_ifwdtsn_hdr *ifwdtsn_hdr;
623         } subh;
624 
625         __u8 *chunk_end;
626 
627         struct sctp_chunkhdr *chunk_hdr;
628         struct sctphdr *sctp_hdr;
629 
630         /* This needs to be recoverable for SCTP_SEND_FAILED events. */
631         struct sctp_sndrcvinfo sinfo;
632 
633         /* Which association does this belong to?  */
634         struct sctp_association *asoc;
635 
636         /* What endpoint received this chunk? */
637         struct sctp_ep_common *rcvr;
638 
639         /* We fill this in if we are calculating RTT. */
640         unsigned long sent_at;
641 
642         /* What is the origin IP address for this chunk?  */
643         union sctp_addr source;
644         /* Destination address for this chunk. */
645         union sctp_addr dest;
646 
647         /* For outbound message, track all fragments for SEND_FAILED. */
648         struct sctp_datamsg *msg;
649 
650         /* For an inbound chunk, this tells us where it came from.
651          * For an outbound chunk, it tells us where we'd like it to
652          * go.  It is NULL if we have no preference.
653          */
654         struct sctp_transport *transport;
655 
656         /* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
657          * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
658          * spec violates the principle premis that all chunks are processed
659          * in order.
660          */
661         struct sk_buff *auth_chunk;
662 
663 #define SCTP_CAN_FRTX 0x0
664 #define SCTP_NEED_FRTX 0x1
665 #define SCTP_DONT_FRTX 0x2
666         __u16   rtt_in_progress:1,      /* This chunk used for RTT calc? */
667                 has_tsn:1,              /* Does this chunk have a TSN yet? */
668                 has_ssn:1,              /* Does this chunk have a SSN yet? */
669 #define has_mid has_ssn
670                 singleton:1,            /* Only chunk in the packet? */
671                 end_of_packet:1,        /* Last chunk in the packet? */
672                 ecn_ce_done:1,          /* Have we processed the ECN CE bit? */
673                 pdiscard:1,             /* Discard the whole packet now? */
674                 tsn_gap_acked:1,        /* Is this chunk acked by a GAP ACK? */
675                 data_accepted:1,        /* At least 1 chunk accepted */
676                 auth:1,                 /* IN: was auth'ed | OUT: needs auth */
677                 has_asconf:1,           /* IN: have seen an asconf before */
678                 tsn_missing_report:2,   /* Data chunk missing counter. */
679                 fast_retransmit:2;      /* Is this chunk fast retransmitted? */
680 };
681 
682 #define sctp_chunk_retransmitted(chunk) (chunk->sent_count > 1)
683 void sctp_chunk_hold(struct sctp_chunk *);
684 void sctp_chunk_put(struct sctp_chunk *);
685 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
686                           struct iov_iter *from);
687 void sctp_chunk_free(struct sctp_chunk *);
688 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
689 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
690                                  const struct sctp_association *,
691                                  struct sock *, gfp_t gfp);
692 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
693                      union sctp_addr *);
694 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
695 
696 static inline __u16 sctp_chunk_stream_no(struct sctp_chunk *ch)
697 {
698         return ntohs(ch->subh.data_hdr->stream);
699 }
700 
701 enum {
702         SCTP_ADDR_NEW,          /* new address added to assoc/ep */
703         SCTP_ADDR_SRC,          /* address can be used as source */
704         SCTP_ADDR_DEL,          /* address about to be deleted */
705 };
706 
707 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
708 struct sctp_sockaddr_entry {
709         struct list_head list;
710         struct rcu_head rcu;
711         union sctp_addr a;
712         __u8 state;
713         __u8 valid;
714 };
715 
716 #define SCTP_ADDRESS_TICK_DELAY 500
717 
718 /* This structure holds lists of chunks as we are assembling for
719  * transmission.
720  */
721 struct sctp_packet {
722         /* These are the SCTP header values (host order) for the packet. */
723         __u16 source_port;
724         __u16 destination_port;
725         __u32 vtag;
726 
727         /* This contains the payload chunks.  */
728         struct list_head chunk_list;
729 
730         /* This is the overhead of the sctp and ip headers. */
731         size_t overhead;
732         /* This is the total size of all chunks INCLUDING padding.  */
733         size_t size;
734         /* This is the maximum size this packet may have */
735         size_t max_size;
736 
737         /* The packet is destined for this transport address.
738          * The function we finally use to pass down to the next lower
739          * layer lives in the transport structure.
740          */
741         struct sctp_transport *transport;
742 
743         /* pointer to the auth chunk for this packet */
744         struct sctp_chunk *auth;
745 
746         u8  has_cookie_echo:1,  /* This packet contains a COOKIE-ECHO chunk. */
747             has_sack:1,         /* This packet contains a SACK chunk. */
748             has_auth:1,         /* This packet contains an AUTH chunk */
749             has_data:1,         /* This packet contains at least 1 DATA chunk */
750             ipfragok:1;         /* So let ip fragment this packet */
751 };
752 
753 void sctp_packet_init(struct sctp_packet *, struct sctp_transport *,
754                       __u16 sport, __u16 dport);
755 void sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
756 enum sctp_xmit sctp_packet_transmit_chunk(struct sctp_packet *packet,
757                                           struct sctp_chunk *chunk,
758                                           int one_packet, gfp_t gfp);
759 enum sctp_xmit sctp_packet_append_chunk(struct sctp_packet *packet,
760                                         struct sctp_chunk *chunk);
761 int sctp_packet_transmit(struct sctp_packet *, gfp_t);
762 void sctp_packet_free(struct sctp_packet *);
763 
764 static inline int sctp_packet_empty(struct sctp_packet *packet)
765 {
766         return packet->size == packet->overhead;
767 }
768 
769 /* This represents a remote transport address.
770  * For local transport addresses, we just use union sctp_addr.
771  *
772  * RFC2960 Section 1.4 Key Terms
773  *
774  *   o  Transport address:  A Transport Address is traditionally defined
775  *      by Network Layer address, Transport Layer protocol and Transport
776  *      Layer port number.  In the case of SCTP running over IP, a
777  *      transport address is defined by the combination of an IP address
778  *      and an SCTP port number (where SCTP is the Transport protocol).
779  *
780  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
781  *
782  *   o  The sender keeps a separate congestion control parameter set for
783  *      each of the destination addresses it can send to (not each
784  *      source-destination pair but for each destination).  The parameters
785  *      should decay if the address is not used for a long enough time
786  *      period.
787  *
788  */
789 struct sctp_transport {
790         /* A list of transports. */
791         struct list_head transports;
792         struct rhlist_head node;
793 
794         /* Reference counting. */
795         refcount_t refcnt;
796                 /* RTO-Pending : A flag used to track if one of the DATA
797                  *              chunks sent to this address is currently being
798                  *              used to compute a RTT. If this flag is 0,
799                  *              the next DATA chunk sent to this destination
800                  *              should be used to compute a RTT and this flag
801                  *              should be set. Every time the RTT
802                  *              calculation completes (i.e. the DATA chunk
803                  *              is SACK'd) clear this flag.
804                  */
805         __u32   rto_pending:1,
806 
807                 /*
808                  * hb_sent : a flag that signals that we have a pending
809                  * heartbeat.
810                  */
811                 hb_sent:1,
812 
813                 /* Is the Path MTU update pending on this tranport */
814                 pmtu_pending:1,
815 
816                 dst_pending_confirm:1,  /* need to confirm neighbour */
817 
818                 /* Has this transport moved the ctsn since we last sacked */
819                 sack_generation:1;
820         u32 dst_cookie;
821 
822         struct flowi fl;
823 
824         /* This is the peer's IP address and port. */
825         union sctp_addr ipaddr;
826 
827         /* These are the functions we call to handle LLP stuff.  */
828         struct sctp_af *af_specific;
829 
830         /* Which association do we belong to?  */
831         struct sctp_association *asoc;
832 
833         /* RFC2960
834          *
835          * 12.3 Per Transport Address Data
836          *
837          * For each destination transport address in the peer's
838          * address list derived from the INIT or INIT ACK chunk, a
839          * number of data elements needs to be maintained including:
840          */
841         /* RTO         : The current retransmission timeout value.  */
842         unsigned long rto;
843 
844         __u32 rtt;              /* This is the most recent RTT.  */
845 
846         /* RTTVAR      : The current RTT variation.  */
847         __u32 rttvar;
848 
849         /* SRTT        : The current smoothed round trip time.  */
850         __u32 srtt;
851 
852         /*
853          * These are the congestion stats.
854          */
855         /* cwnd        : The current congestion window.  */
856         __u32 cwnd;               /* This is the actual cwnd.  */
857 
858         /* ssthresh    : The current slow start threshold value.  */
859         __u32 ssthresh;
860 
861         /* partial     : The tracking method for increase of cwnd when in
862          * bytes acked : congestion avoidance mode (see Section 6.2.2)
863          */
864         __u32 partial_bytes_acked;
865 
866         /* Data that has been sent, but not acknowledged. */
867         __u32 flight_size;
868 
869         __u32 burst_limited;    /* Holds old cwnd when max.burst is applied */
870 
871         /* Destination */
872         struct dst_entry *dst;
873         /* Source address. */
874         union sctp_addr saddr;
875 
876         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
877          * the destination address every heartbeat interval.
878          */
879         unsigned long hbinterval;
880 
881         /* SACK delay timeout */
882         unsigned long sackdelay;
883         __u32 sackfreq;
884 
885         atomic_t mtu_info;
886 
887         /* When was the last time that we heard from this transport? We use
888          * this to pick new active and retran paths.
889          */
890         ktime_t last_time_heard;
891 
892         /* When was the last time that we sent a chunk using this
893          * transport? We use this to check for idle transports
894          */
895         unsigned long last_time_sent;
896 
897         /* Last time(in jiffies) when cwnd is reduced due to the congestion
898          * indication based on ECNE chunk.
899          */
900         unsigned long last_time_ecne_reduced;
901 
902         /* This is the max_retrans value for the transport and will
903          * be initialized from the assocs value.  This can be changed
904          * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
905          */
906         __u16 pathmaxrxt;
907 
908         __u32 flowlabel;
909         __u8  dscp;
910 
911         /* This is the partially failed retrans value for the transport
912          * and will be initialized from the assocs value.  This can be changed
913          * using the SCTP_PEER_ADDR_THLDS socket option
914          */
915         int pf_retrans;
916         /* PMTU       : The current known path MTU.  */
917         __u32 pathmtu;
918 
919         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
920         __u32 param_flags;
921 
922         /* The number of times INIT has been sent on this transport. */
923         int init_sent_count;
924 
925         /* state       : The current state of this destination,
926          *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
927          */
928         int state;
929 
930         /* These are the error stats for this destination.  */
931 
932         /* Error count : The current error count for this destination.  */
933         unsigned short error_count;
934 
935         /* Per         : A timer used by each destination.
936          * Destination :
937          * Timer       :
938          *
939          * [Everywhere else in the text this is called T3-rtx. -ed]
940          */
941         struct timer_list T3_rtx_timer;
942 
943         /* Heartbeat timer is per destination. */
944         struct timer_list hb_timer;
945 
946         /* Timer to handle ICMP proto unreachable envets */
947         struct timer_list proto_unreach_timer;
948 
949         /* Timer to handler reconf chunk rtx */
950         struct timer_list reconf_timer;
951 
952         /* Since we're using per-destination retransmission timers
953          * (see above), we're also using per-destination "transmitted"
954          * queues.  This probably ought to be a private struct
955          * accessible only within the outqueue, but it's not, yet.
956          */
957         struct list_head transmitted;
958 
959         /* We build bundle-able packets for this transport here.  */
960         struct sctp_packet packet;
961 
962         /* This is the list of transports that have chunks to send.  */
963         struct list_head send_ready;
964 
965         /* State information saved for SFR_CACC algorithm. The key
966          * idea in SFR_CACC is to maintain state at the sender on a
967          * per-destination basis when a changeover happens.
968          *      char changeover_active;
969          *      char cycling_changeover;
970          *      __u32 next_tsn_at_change;
971          *      char cacc_saw_newack;
972          */
973         struct {
974                 /* An unsigned integer, which stores the next TSN to be
975                  * used by the sender, at the moment of changeover.
976                  */
977                 __u32 next_tsn_at_change;
978 
979                 /* A flag which indicates the occurrence of a changeover */
980                 char changeover_active;
981 
982                 /* A flag which indicates whether the change of primary is
983                  * the first switch to this destination address during an
984                  * active switch.
985                  */
986                 char cycling_changeover;
987 
988                 /* A temporary flag, which is used during the processing of
989                  * a SACK to estimate the causative TSN(s)'s group.
990                  */
991                 char cacc_saw_newack;
992         } cacc;
993 
994         /* 64-bit random number sent with heartbeat. */
995         __u64 hb_nonce;
996 
997         struct rcu_head rcu;
998 };
999 
1000 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
1001                                           gfp_t);
1002 void sctp_transport_set_owner(struct sctp_transport *,
1003                               struct sctp_association *);
1004 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1005                           struct sctp_sock *);
1006 void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
1007 void sctp_transport_free(struct sctp_transport *);
1008 void sctp_transport_reset_t3_rtx(struct sctp_transport *);
1009 void sctp_transport_reset_hb_timer(struct sctp_transport *);
1010 void sctp_transport_reset_reconf_timer(struct sctp_transport *transport);
1011 int sctp_transport_hold(struct sctp_transport *);
1012 void sctp_transport_put(struct sctp_transport *);
1013 void sctp_transport_update_rto(struct sctp_transport *, __u32);
1014 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1015 void sctp_transport_lower_cwnd(struct sctp_transport *t,
1016                                enum sctp_lower_cwnd reason);
1017 void sctp_transport_burst_limited(struct sctp_transport *);
1018 void sctp_transport_burst_reset(struct sctp_transport *);
1019 unsigned long sctp_transport_timeout(struct sctp_transport *);
1020 void sctp_transport_reset(struct sctp_transport *t);
1021 bool sctp_transport_update_pmtu(struct sctp_transport *t, u32 pmtu);
1022 void sctp_transport_immediate_rtx(struct sctp_transport *);
1023 void sctp_transport_dst_release(struct sctp_transport *t);
1024 void sctp_transport_dst_confirm(struct sctp_transport *t);
1025 
1026 
1027 /* This is the structure we use to queue packets as they come into
1028  * SCTP.  We write packets to it and read chunks from it.
1029  */
1030 struct sctp_inq {
1031         /* This is actually a queue of sctp_chunk each
1032          * containing a partially decoded packet.
1033          */
1034         struct list_head in_chunk_list;
1035         /* This is the packet which is currently off the in queue and is
1036          * being worked on through the inbound chunk processing.
1037          */
1038         struct sctp_chunk *in_progress;
1039 
1040         /* This is the delayed task to finish delivering inbound
1041          * messages.
1042          */
1043         struct work_struct immediate;
1044 };
1045 
1046 void sctp_inq_init(struct sctp_inq *);
1047 void sctp_inq_free(struct sctp_inq *);
1048 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1049 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1050 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1051 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1052 
1053 /* This is the structure we use to hold outbound chunks.  You push
1054  * chunks in and they automatically pop out the other end as bundled
1055  * packets (it calls (*output_handler)()).
1056  *
1057  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1058  * and 8.2 of the v13 draft.
1059  *
1060  * It handles retransmissions.  The connection to the timeout portion
1061  * of the state machine is through sctp_..._timeout() and timeout_handler.
1062  *
1063  * If you feed it SACKs, it will eat them.
1064  *
1065  * If you give it big chunks, it will fragment them.
1066  *
1067  * It assigns TSN's to data chunks.  This happens at the last possible
1068  * instant before transmission.
1069  *
1070  * When free()'d, it empties itself out via output_handler().
1071  */
1072 struct sctp_outq {
1073         struct sctp_association *asoc;
1074 
1075         /* Data pending that has never been transmitted.  */
1076         struct list_head out_chunk_list;
1077 
1078         /* Stream scheduler being used */
1079         struct sctp_sched_ops *sched;
1080 
1081         unsigned int out_qlen;  /* Total length of queued data chunks. */
1082 
1083         /* Error of send failed, may used in SCTP_SEND_FAILED event. */
1084         unsigned int error;
1085 
1086         /* These are control chunks we want to send.  */
1087         struct list_head control_chunk_list;
1088 
1089         /* These are chunks that have been sacked but are above the
1090          * CTSN, or cumulative tsn ack point.
1091          */
1092         struct list_head sacked;
1093 
1094         /* Put chunks on this list to schedule them for
1095          * retransmission.
1096          */
1097         struct list_head retransmit;
1098 
1099         /* Put chunks on this list to save them for FWD TSN processing as
1100          * they were abandoned.
1101          */
1102         struct list_head abandoned;
1103 
1104         /* How many unackd bytes do we have in-flight?  */
1105         __u32 outstanding_bytes;
1106 
1107         /* Are we doing fast-rtx on this queue */
1108         char fast_rtx;
1109 
1110         /* Corked? */
1111         char cork;
1112 };
1113 
1114 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1115 void sctp_outq_teardown(struct sctp_outq *);
1116 void sctp_outq_free(struct sctp_outq*);
1117 void sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk, gfp_t);
1118 int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
1119 int sctp_outq_is_empty(const struct sctp_outq *);
1120 void sctp_outq_restart(struct sctp_outq *);
1121 
1122 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
1123                      enum sctp_retransmit_reason reason);
1124 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1125 void sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
1126 void sctp_prsctp_prune(struct sctp_association *asoc,
1127                        struct sctp_sndrcvinfo *sinfo, int msg_len);
1128 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
1129 /* Uncork and flush an outqueue.  */
1130 static inline void sctp_outq_cork(struct sctp_outq *q)
1131 {
1132         q->cork = 1;
1133 }
1134 
1135 /* SCTP skb control block.
1136  * sctp_input_cb is currently used on rx and sock rx queue
1137  */
1138 struct sctp_input_cb {
1139         union {
1140                 struct inet_skb_parm    h4;
1141 #if IS_ENABLED(CONFIG_IPV6)
1142                 struct inet6_skb_parm   h6;
1143 #endif
1144         } header;
1145         struct sctp_chunk *chunk;
1146         struct sctp_af *af;
1147 };
1148 #define SCTP_INPUT_CB(__skb)    ((struct sctp_input_cb *)&((__skb)->cb[0]))
1149 
1150 struct sctp_output_cb {
1151         struct sk_buff *last;
1152 };
1153 #define SCTP_OUTPUT_CB(__skb)   ((struct sctp_output_cb *)&((__skb)->cb[0]))
1154 
1155 static inline const struct sk_buff *sctp_gso_headskb(const struct sk_buff *skb)
1156 {
1157         const struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
1158 
1159         return chunk->head_skb ? : skb;
1160 }
1161 
1162 /* These bind address data fields common between endpoints and associations */
1163 struct sctp_bind_addr {
1164 
1165         /* RFC 2960 12.1 Parameters necessary for the SCTP instance
1166          *
1167          * SCTP Port:   The local SCTP port number the endpoint is
1168          *              bound to.
1169          */
1170         __u16 port;
1171 
1172         /* RFC 2960 12.1 Parameters necessary for the SCTP instance
1173          *
1174          * Address List: The list of IP addresses that this instance
1175          *      has bound.  This information is passed to one's
1176          *      peer(s) in INIT and INIT ACK chunks.
1177          */
1178         struct list_head address_list;
1179 };
1180 
1181 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1182 void sctp_bind_addr_free(struct sctp_bind_addr *);
1183 int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
1184                         const struct sctp_bind_addr *src,
1185                         enum sctp_scope scope, gfp_t gfp,
1186                         int flags);
1187 int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
1188                         const struct sctp_bind_addr *src,
1189                         gfp_t gfp);
1190 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1191                        int new_size, __u8 addr_state, gfp_t gfp);
1192 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
1193 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1194                          struct sctp_sock *);
1195 int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
1196                          struct sctp_sock *, struct sctp_sock *);
1197 int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
1198                          const union sctp_addr *addr);
1199 int sctp_bind_addrs_check(struct sctp_sock *sp,
1200                           struct sctp_sock *sp2, int cnt2);
1201 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr   *bp,
1202                                         const union sctp_addr   *addrs,
1203                                         int                     addrcnt,
1204                                         struct sctp_sock        *opt);
1205 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1206                                          int *addrs_len,
1207                                          gfp_t gfp);
1208 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1209                            __u16 port, gfp_t gfp);
1210 
1211 enum sctp_scope sctp_scope(const union sctp_addr *addr);
1212 int sctp_in_scope(struct net *net, const union sctp_addr *addr,
1213                   const enum sctp_scope scope);
1214 int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
1215 int sctp_is_ep_boundall(struct sock *sk);
1216 
1217 
1218 /* What type of endpoint?  */
1219 enum sctp_endpoint_type {
1220         SCTP_EP_TYPE_SOCKET,
1221         SCTP_EP_TYPE_ASSOCIATION,
1222 };
1223 
1224 /*
1225  * A common base class to bridge the implmentation view of a
1226  * socket (usually listening) endpoint versus an association's
1227  * local endpoint.
1228  * This common structure is useful for several purposes:
1229  *   1) Common interface for lookup routines.
1230  *      a) Subfunctions work for either endpoint or association
1231  *      b) Single interface to lookup allows hiding the lookup lock rather
1232  *         than acquiring it externally.
1233  *   2) Common interface for the inbound chunk handling/state machine.
1234  *   3) Common object handling routines for reference counting, etc.
1235  *   4) Disentangle association lookup from endpoint lookup, where we
1236  *      do not have to find our endpoint to find our association.
1237  *
1238  */
1239 
1240 struct sctp_ep_common {
1241         /* Fields to help us manage our entries in the hash tables. */
1242         struct hlist_node node;
1243         int hashent;
1244 
1245         /* Runtime type information.  What kind of endpoint is this? */
1246         enum sctp_endpoint_type type;
1247 
1248         /* Some fields to help us manage this object.
1249          *   refcnt   - Reference count access to this object.
1250          *   dead     - Do not attempt to use this object.
1251          */
1252         refcount_t    refcnt;
1253         bool        dead;
1254 
1255         /* What socket does this endpoint belong to?  */
1256         struct sock *sk;
1257 
1258         /* This is where we receive inbound chunks.  */
1259         struct sctp_inq   inqueue;
1260 
1261         /* This substructure includes the defining parameters of the
1262          * endpoint:
1263          * bind_addr.port is our shared port number.
1264          * bind_addr.address_list is our set of local IP addresses.
1265          */
1266         struct sctp_bind_addr bind_addr;
1267 };
1268 
1269 
1270 /* RFC Section 1.4 Key Terms
1271  *
1272  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1273  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1274  *   combination of a set of eligible destination transport addresses to
1275  *   which SCTP packets can be sent and a set of eligible source
1276  *   transport addresses from which SCTP packets can be received.
1277  *   All transport addresses used by an SCTP endpoint must use the
1278  *   same port number, but can use multiple IP addresses. A transport
1279  *   address used by an SCTP endpoint must not be used by another
1280  *   SCTP endpoint. In other words, a transport address is unique
1281  *   to an SCTP endpoint.
1282  *
1283  * From an implementation perspective, each socket has one of these.
1284  * A TCP-style socket will have exactly one association on one of
1285  * these.  An UDP-style socket will have multiple associations hanging
1286  * off one of these.
1287  */
1288 
1289 struct sctp_endpoint {
1290         /* Common substructure for endpoint and association. */
1291         struct sctp_ep_common base;
1292 
1293         /* Associations: A list of current associations and mappings
1294          *            to the data consumers for each association. This
1295          *            may be in the form of a hash table or other
1296          *            implementation dependent structure. The data
1297          *            consumers may be process identification
1298          *            information such as file descriptors, named pipe
1299          *            pointer, or table pointers dependent on how SCTP
1300          *            is implemented.
1301          */
1302         /* This is really a list of struct sctp_association entries. */
1303         struct list_head asocs;
1304 
1305         /* Secret Key: A secret key used by this endpoint to compute
1306          *            the MAC.  This SHOULD be a cryptographic quality
1307          *            random number with a sufficient length.
1308          *            Discussion in [RFC1750] can be helpful in
1309          *            selection of the key.
1310          */
1311         __u8 secret_key[SCTP_SECRET_SIZE];
1312 
1313         /* digest:  This is a digest of the sctp cookie.  This field is
1314          *          only used on the receive path when we try to validate
1315          *          that the cookie has not been tampered with.  We put
1316          *          this here so we pre-allocate this once and can re-use
1317          *          on every receive.
1318          */
1319         __u8 *digest;
1320  
1321         /* sendbuf acct. policy.        */
1322         __u32 sndbuf_policy;
1323 
1324         /* rcvbuf acct. policy. */
1325         __u32 rcvbuf_policy;
1326 
1327         /* SCTP AUTH: array of the HMACs that will be allocated
1328          * we need this per association so that we don't serialize
1329          */
1330         struct crypto_shash **auth_hmacs;
1331 
1332         /* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1333          struct sctp_hmac_algo_param *auth_hmacs_list;
1334 
1335         /* SCTP-AUTH: chunks to authenticate encoded into parameter */
1336         struct sctp_chunks_param *auth_chunk_list;
1337 
1338         /* SCTP-AUTH: endpoint shared keys */
1339         struct list_head endpoint_shared_keys;
1340         __u16 active_key_id;
1341         __u8  auth_enable:1,
1342               prsctp_enable:1,
1343               reconf_enable:1;
1344 
1345         __u8  strreset_enable;
1346 
1347         /* Security identifiers from incoming (INIT). These are set by
1348          * security_sctp_assoc_request(). These will only be used by
1349          * SCTP TCP type sockets and peeled off connections as they
1350          * cause a new socket to be generated. security_sctp_sk_clone()
1351          * will then plug these into the new socket.
1352          */
1353 
1354         u32 secid;
1355         u32 peer_secid;
1356 };
1357 
1358 /* Recover the outter endpoint structure. */
1359 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1360 {
1361         struct sctp_endpoint *ep;
1362 
1363         ep = container_of(base, struct sctp_endpoint, base);
1364         return ep;
1365 }
1366 
1367 /* These are function signatures for manipulating endpoints.  */
1368 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1369 void sctp_endpoint_free(struct sctp_endpoint *);
1370 void sctp_endpoint_put(struct sctp_endpoint *);
1371 void sctp_endpoint_hold(struct sctp_endpoint *);
1372 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1373 struct sctp_association *sctp_endpoint_lookup_assoc(
1374         const struct sctp_endpoint *ep,
1375         const union sctp_addr *paddr,
1376         struct sctp_transport **);
1377 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
1378                                  const union sctp_addr *paddr);
1379 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1380                                         struct net *, const union sctp_addr *);
1381 bool sctp_has_association(struct net *net, const union sctp_addr *laddr,
1382                           const union sctp_addr *paddr);
1383 
1384 int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
1385                      const struct sctp_association *asoc,
1386                      enum sctp_cid cid, struct sctp_init_chunk *peer_init,
1387                      struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
1388 int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
1389                       const union sctp_addr *peer,
1390                       struct sctp_init_chunk *init, gfp_t gfp);
1391 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1392 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1393 
1394 struct sctp_inithdr_host {
1395         __u32 init_tag;
1396         __u32 a_rwnd;
1397         __u16 num_outbound_streams;
1398         __u16 num_inbound_streams;
1399         __u32 initial_tsn;
1400 };
1401 
1402 struct sctp_stream_priorities {
1403         /* List of priorities scheduled */
1404         struct list_head prio_sched;
1405         /* List of streams scheduled */
1406         struct list_head active;
1407         /* The next stream stream in line */
1408         struct sctp_stream_out_ext *next;
1409         __u16 prio;
1410 };
1411 
1412 struct sctp_stream_out_ext {
1413         __u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
1414         __u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
1415         struct list_head outq; /* chunks enqueued by this stream */
1416         union {
1417                 struct {
1418                         /* Scheduled streams list */
1419                         struct list_head prio_list;
1420                         struct sctp_stream_priorities *prio_head;
1421                 };
1422                 /* Fields used by RR scheduler */
1423                 struct {
1424                         struct list_head rr_list;
1425                 };
1426         };
1427 };
1428 
1429 struct sctp_stream_out {
1430         union {
1431                 __u32 mid;
1432                 __u16 ssn;
1433         };
1434         __u32 mid_uo;
1435         struct sctp_stream_out_ext *ext;
1436         __u8 state;
1437 };
1438 
1439 struct sctp_stream_in {
1440         union {
1441                 __u32 mid;
1442                 __u16 ssn;
1443         };
1444         __u32 mid_uo;
1445         __u32 fsn;
1446         __u32 fsn_uo;
1447         char pd_mode;
1448         char pd_mode_uo;
1449 };
1450 
1451 struct sctp_stream {
1452         GENRADIX(struct sctp_stream_out) out;
1453         GENRADIX(struct sctp_stream_in) in;
1454 
1455         __u16 outcnt;
1456         __u16 incnt;
1457         /* Current stream being sent, if any */
1458         struct sctp_stream_out *out_curr;
1459         union {
1460                 /* Fields used by priority scheduler */
1461                 struct {
1462                         /* List of priorities scheduled */
1463                         struct list_head prio_list;
1464                 };
1465                 /* Fields used by RR scheduler */
1466                 struct {
1467                         /* List of streams scheduled */
1468                         struct list_head rr_list;
1469                         /* The next stream stream in line */
1470                         struct sctp_stream_out_ext *rr_next;
1471                 };
1472         };
1473         struct sctp_stream_interleave *si;
1474 };
1475 
1476 static inline struct sctp_stream_out *sctp_stream_out(
1477         struct sctp_stream *stream,
1478         __u16 sid)
1479 {
1480         return genradix_ptr(&stream->out, sid);
1481 }
1482 
1483 static inline struct sctp_stream_in *sctp_stream_in(
1484         struct sctp_stream *stream,
1485         __u16 sid)
1486 {
1487         return genradix_ptr(&stream->in, sid);
1488 }
1489 
1490 #define SCTP_SO(s, i) sctp_stream_out((s), (i))
1491 #define SCTP_SI(s, i) sctp_stream_in((s), (i))
1492 
1493 #define SCTP_STREAM_CLOSED              0x00
1494 #define SCTP_STREAM_OPEN                0x01
1495 
1496 static inline __u16 sctp_datachk_len(const struct sctp_stream *stream)
1497 {
1498         return stream->si->data_chunk_len;
1499 }
1500 
1501 static inline __u16 sctp_datahdr_len(const struct sctp_stream *stream)
1502 {
1503         return stream->si->data_chunk_len - sizeof(struct sctp_chunkhdr);
1504 }
1505 
1506 static inline __u16 sctp_ftsnchk_len(const struct sctp_stream *stream)
1507 {
1508         return stream->si->ftsn_chunk_len;
1509 }
1510 
1511 static inline __u16 sctp_ftsnhdr_len(const struct sctp_stream *stream)
1512 {
1513         return stream->si->ftsn_chunk_len - sizeof(struct sctp_chunkhdr);
1514 }
1515 
1516 /* SCTP_GET_ASSOC_STATS counters */
1517 struct sctp_priv_assoc_stats {
1518         /* Maximum observed rto in the association during subsequent
1519          * observations. Value is set to 0 if no RTO measurement took place
1520          * The transport where the max_rto was observed is returned in
1521          * obs_rto_ipaddr
1522          */
1523         struct sockaddr_storage obs_rto_ipaddr;
1524         __u64 max_obs_rto;
1525         /* Total In and Out SACKs received and sent */
1526         __u64 isacks;
1527         __u64 osacks;
1528         /* Total In and Out packets received and sent */
1529         __u64 opackets;
1530         __u64 ipackets;
1531         /* Total retransmitted chunks */
1532         __u64 rtxchunks;
1533         /* TSN received > next expected */
1534         __u64 outofseqtsns;
1535         /* Duplicate Chunks received */
1536         __u64 idupchunks;
1537         /* Gap Ack Blocks received */
1538         __u64 gapcnt;
1539         /* Unordered data chunks sent and received */
1540         __u64 ouodchunks;
1541         __u64 iuodchunks;
1542         /* Ordered data chunks sent and received */
1543         __u64 oodchunks;
1544         __u64 iodchunks;
1545         /* Control chunks sent and received */
1546         __u64 octrlchunks;
1547         __u64 ictrlchunks;
1548 };
1549 
1550 /* RFC2960
1551  *
1552  * 12. Recommended Transmission Control Block (TCB) Parameters
1553  *
1554  * This section details a recommended set of parameters that should
1555  * be contained within the TCB for an implementation. This section is
1556  * for illustrative purposes and should not be deemed as requirements
1557  * on an implementation or as an exhaustive list of all parameters
1558  * inside an SCTP TCB. Each implementation may need its own additional
1559  * parameters for optimization.
1560  */
1561 
1562 
1563 /* Here we have information about each individual association. */
1564 struct sctp_association {
1565 
1566         /* A base structure common to endpoint and association.
1567          * In this context, it represents the associations's view
1568          * of the local endpoint of the association.
1569          */
1570         struct sctp_ep_common base;
1571 
1572         /* Associations on the same socket. */
1573         struct list_head asocs;
1574 
1575         /* association id. */
1576         sctp_assoc_t assoc_id;
1577 
1578         /* This is our parent endpoint.  */
1579         struct sctp_endpoint *ep;
1580 
1581         /* These are those association elements needed in the cookie.  */
1582         struct sctp_cookie c;
1583 
1584         /* This is all information about our peer.  */
1585         struct {
1586                 /* transport_addr_list
1587                  *
1588                  * Peer        : A list of SCTP transport addresses that the
1589                  * Transport   : peer is bound to. This information is derived
1590                  * Address     : from the INIT or INIT ACK and is used to
1591                  * List        : associate an inbound packet with a given
1592                  *             : association. Normally this information is
1593                  *             : hashed or keyed for quick lookup and access
1594                  *             : of the TCB.
1595                  *             : The list is also initialized with the list
1596                  *             : of addresses passed with the sctp_connectx()
1597                  *             : call.
1598                  *
1599                  * It is a list of SCTP_transport's.
1600                  */
1601                 struct list_head transport_addr_list;
1602 
1603                 /* rwnd
1604                  *
1605                  * Peer Rwnd   : Current calculated value of the peer's rwnd.
1606                  */
1607                 __u32 rwnd;
1608 
1609                 /* transport_count
1610                  *
1611                  * Peer        : A count of the number of peer addresses
1612                  * Transport   : in the Peer Transport Address List.
1613                  * Address     :
1614                  * Count       :
1615                  */
1616                 __u16 transport_count;
1617 
1618                 /* port
1619                  *   The transport layer port number.
1620                  */
1621                 __u16 port;
1622 
1623                 /* primary_path
1624                  *
1625                  * Primary     : This is the current primary destination
1626                  * Path        : transport address of the peer endpoint.  It
1627                  *             : may also specify a source transport address
1628                  *             : on this endpoint.
1629                  *
1630                  * All of these paths live on transport_addr_list.
1631                  *
1632                  * At the bakeoffs, we discovered that the intent of
1633                  * primaryPath is that it only changes when the ULP
1634                  * asks to have it changed.  We add the activePath to
1635                  * designate the connection we are currently using to
1636                  * transmit new data and most control chunks.
1637                  */
1638                 struct sctp_transport *primary_path;
1639 
1640                 /* Cache the primary path address here, when we
1641                  * need a an address for msg_name.
1642                  */
1643                 union sctp_addr primary_addr;
1644 
1645                 /* active_path
1646                  *   The path that we are currently using to
1647                  *   transmit new data and most control chunks.
1648                  */
1649                 struct sctp_transport *active_path;
1650 
1651                 /* retran_path
1652                  *
1653                  * RFC2960 6.4 Multi-homed SCTP Endpoints
1654                  * ...
1655                  * Furthermore, when its peer is multi-homed, an
1656                  * endpoint SHOULD try to retransmit a chunk to an
1657                  * active destination transport address that is
1658                  * different from the last destination address to
1659                  * which the DATA chunk was sent.
1660                  */
1661                 struct sctp_transport *retran_path;
1662 
1663                 /* Pointer to last transport I have sent on.  */
1664                 struct sctp_transport *last_sent_to;
1665 
1666                 /* This is the last transport I have received DATA on.  */
1667                 struct sctp_transport *last_data_from;
1668 
1669                 /*
1670                  * Mapping  An array of bits or bytes indicating which out of
1671                  * Array    order TSN's have been received (relative to the
1672                  *          Last Rcvd TSN). If no gaps exist, i.e. no out of
1673                  *          order packets have been received, this array
1674                  *          will be set to all zero. This structure may be
1675                  *          in the form of a circular buffer or bit array.
1676                  *
1677                  * Last Rcvd   : This is the last TSN received in
1678                  * TSN         : sequence. This value is set initially by
1679                  *             : taking the peer's Initial TSN, received in
1680                  *             : the INIT or INIT ACK chunk, and subtracting
1681                  *             : one from it.
1682                  *
1683                  * Throughout most of the specification this is called the
1684                  * "Cumulative TSN ACK Point".  In this case, we
1685                  * ignore the advice in 12.2 in favour of the term
1686                  * used in the bulk of the text.  This value is hidden
1687                  * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1688                  */
1689                 struct sctp_tsnmap tsn_map;
1690 
1691                 /* This mask is used to disable sending the ASCONF chunk
1692                  * with specified parameter to peer.
1693                  */
1694                 __be16 addip_disabled_mask;
1695 
1696                 /* These are capabilities which our peer advertised.  */
1697                 __u8    ecn_capable:1,      /* Can peer do ECN? */
1698                         ipv4_address:1,     /* Peer understands IPv4 addresses? */
1699                         ipv6_address:1,     /* Peer understands IPv6 addresses? */
1700                         hostname_address:1, /* Peer understands DNS addresses? */
1701                         asconf_capable:1,   /* Does peer support ADDIP? */
1702                         prsctp_capable:1,   /* Can peer do PR-SCTP? */
1703                         reconf_capable:1,   /* Can peer do RE-CONFIG? */
1704                         auth_capable:1;     /* Is peer doing SCTP-AUTH? */
1705 
1706                 /* sack_needed : This flag indicates if the next received
1707                  *             : packet is to be responded to with a
1708                  *             : SACK. This is initialized to 0.  When a packet
1709                  *             : is received sack_cnt is incremented. If this value
1710                  *             : reaches 2 or more, a SACK is sent and the
1711                  *             : value is reset to 0. Note: This is used only
1712                  *             : when no DATA chunks are received out of
1713                  *             : order.  When DATA chunks are out of order,
1714                  *             : SACK's are not delayed (see Section 6).
1715                  */
1716                 __u8    sack_needed:1,     /* Do we need to sack the peer? */
1717                         sack_generation:1,
1718                         zero_window_announced:1;
1719                 __u32   sack_cnt;
1720 
1721                 __u32   adaptation_ind;  /* Adaptation Code point. */
1722 
1723                 struct sctp_inithdr_host i;
1724                 void *cookie;
1725                 int cookie_len;
1726 
1727                 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1728                  * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1729                  * Initial TSN Value minus 1
1730                  */
1731                 __u32 addip_serial;
1732 
1733                 /* SCTP-AUTH: We need to know pears random number, hmac list
1734                  * and authenticated chunk list.  All that is part of the
1735                  * cookie and these are just pointers to those locations
1736                  */
1737                 struct sctp_random_param *peer_random;
1738                 struct sctp_chunks_param *peer_chunks;
1739                 struct sctp_hmac_algo_param *peer_hmacs;
1740         } peer;
1741 
1742         /* State       : A state variable indicating what state the
1743          *             : association is in, i.e. COOKIE-WAIT,
1744          *             : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1745          *             : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1746          *
1747          *              Note: No "CLOSED" state is illustrated since if a
1748          *              association is "CLOSED" its TCB SHOULD be removed.
1749          *
1750          *              In this implementation we DO have a CLOSED
1751          *              state which is used during initiation and shutdown.
1752          *
1753          *              State takes values from SCTP_STATE_*.
1754          */
1755         enum sctp_state state;
1756 
1757         /* Overall     : The overall association error count.
1758          * Error Count : [Clear this any time I get something.]
1759          */
1760         int overall_error_count;
1761 
1762         /* The cookie life I award for any cookie.  */
1763         ktime_t cookie_life;
1764 
1765         /* These are the association's initial, max, and min RTO values.
1766          * These values will be initialized by system defaults, but can
1767          * be modified via the SCTP_RTOINFO socket option.
1768          */
1769         unsigned long rto_initial;
1770         unsigned long rto_max;
1771         unsigned long rto_min;
1772 
1773         /* Maximum number of new data packets that can be sent in a burst.  */
1774         int max_burst;
1775 
1776         /* This is the max_retrans value for the association.  This value will
1777          * be initialized initialized from system defaults, but can be
1778          * modified by the SCTP_ASSOCINFO socket option.
1779          */
1780         int max_retrans;
1781 
1782         /* This is the partially failed retrans value for the transport
1783          * and will be initialized from the assocs value.  This can be
1784          * changed using the SCTP_PEER_ADDR_THLDS socket option
1785          */
1786         int pf_retrans;
1787 
1788         /* Maximum number of times the endpoint will retransmit INIT  */
1789         __u16 max_init_attempts;
1790 
1791         /* How many times have we resent an INIT? */
1792         __u16 init_retries;
1793 
1794         /* The largest timeout or RTO value to use in attempting an INIT */
1795         unsigned long max_init_timeo;
1796 
1797         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1798          * the destination address every heartbeat interval. This value
1799          * will be inherited by all new transports.
1800          */
1801         unsigned long hbinterval;
1802 
1803         /* This is the max_retrans value for new transports in the
1804          * association.
1805          */
1806         __u16 pathmaxrxt;
1807 
1808         __u32 flowlabel;
1809         __u8  dscp;
1810 
1811         /* Flag that path mtu update is pending */
1812         __u8   pmtu_pending;
1813 
1814         /* Association : The smallest PMTU discovered for all of the
1815          * PMTU        : peer's transport addresses.
1816          */
1817         __u32 pathmtu;
1818 
1819         /* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
1820         __u32 param_flags;
1821 
1822         __u32 sackfreq;
1823         /* SACK delay timeout */
1824         unsigned long sackdelay;
1825 
1826         unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1827         struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1828 
1829         /* Transport to which SHUTDOWN chunk was last sent.  */
1830         struct sctp_transport *shutdown_last_sent_to;
1831 
1832         /* Transport to which INIT chunk was last sent.  */
1833         struct sctp_transport *init_last_sent_to;
1834 
1835         /* How many times have we resent a SHUTDOWN */
1836         int shutdown_retries;
1837 
1838         /* Next TSN    : The next TSN number to be assigned to a new
1839          *             : DATA chunk.  This is sent in the INIT or INIT
1840          *             : ACK chunk to the peer and incremented each
1841          *             : time a DATA chunk is assigned a TSN
1842          *             : (normally just prior to transmit or during
1843          *             : fragmentation).
1844          */
1845         __u32 next_tsn;
1846 
1847         /*
1848          * Last Rcvd   : This is the last TSN received in sequence.  This value
1849          * TSN         : is set initially by taking the peer's Initial TSN,
1850          *             : received in the INIT or INIT ACK chunk, and
1851          *             : subtracting one from it.
1852          *
1853          * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1854          */
1855 
1856         __u32 ctsn_ack_point;
1857 
1858         /* PR-SCTP Advanced.Peer.Ack.Point */
1859         __u32 adv_peer_ack_point;
1860 
1861         /* Highest TSN that is acknowledged by incoming SACKs. */
1862         __u32 highest_sacked;
1863 
1864         /* TSN marking the fast recovery exit point */
1865         __u32 fast_recovery_exit;
1866 
1867         /* Flag to track the current fast recovery state */
1868         __u8 fast_recovery;
1869 
1870         /* The number of unacknowledged data chunks.  Reported through
1871          * the SCTP_STATUS sockopt.
1872          */
1873         __u16 unack_data;
1874 
1875         /* The total number of data chunks that we've had to retransmit
1876          * as the result of a T3 timer expiration
1877          */
1878         __u32 rtx_data_chunks;
1879 
1880         /* This is the association's receive buffer space.  This value is used
1881          * to set a_rwnd field in an INIT or a SACK chunk.
1882          */
1883         __u32 rwnd;
1884 
1885         /* This is the last advertised value of rwnd over a SACK chunk. */
1886         __u32 a_rwnd;
1887 
1888         /* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1889          * to slop over a maximum of the association's frag_point.
1890          */
1891         __u32 rwnd_over;
1892 
1893         /* Keeps treack of rwnd pressure.  This happens when we have
1894          * a window, but not recevie buffer (i.e small packets).  This one
1895          * is releases slowly (1 PMTU at a time ).
1896          */
1897         __u32 rwnd_press;
1898 
1899         /* This is the sndbuf size in use for the association.
1900          * This corresponds to the sndbuf size for the association,
1901          * as specified in the sk->sndbuf.
1902          */
1903         int sndbuf_used;
1904 
1905         /* This is the amount of memory that this association has allocated
1906          * in the receive path at any given time.
1907          */
1908         atomic_t rmem_alloc;
1909 
1910         /* This is the wait queue head for send requests waiting on
1911          * the association sndbuf space.
1912          */
1913         wait_queue_head_t       wait;
1914 
1915         /* The message size at which SCTP fragmentation will occur. */
1916         __u32 frag_point;
1917         __u32 user_frag;
1918 
1919         /* Counter used to count INIT errors. */
1920         int init_err_counter;
1921 
1922         /* Count the number of INIT cycles (for doubling timeout). */
1923         int init_cycle;
1924 
1925         /* Default send parameters. */
1926         __u16 default_stream;
1927         __u16 default_flags;
1928         __u32 default_ppid;
1929         __u32 default_context;
1930         __u32 default_timetolive;
1931 
1932         /* Default receive parameters */
1933         __u32 default_rcv_context;
1934 
1935         /* Stream arrays */
1936         struct sctp_stream stream;
1937 
1938         /* All outbound chunks go through this structure.  */
1939         struct sctp_outq outqueue;
1940 
1941         /* A smart pipe that will handle reordering and fragmentation,
1942          * as well as handle passing events up to the ULP.
1943          */
1944         struct sctp_ulpq ulpq;
1945 
1946         /* Last TSN that caused an ECNE Chunk to be sent.  */
1947         __u32 last_ecne_tsn;
1948 
1949         /* Last TSN that caused a CWR Chunk to be sent.  */
1950         __u32 last_cwr_tsn;
1951 
1952         /* How many duplicated TSNs have we seen?  */
1953         int numduptsns;
1954 
1955         /* These are to support
1956          * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1957          *  and Enforcement of Flow and Message Limits"
1958          * <draft-ietf-tsvwg-addip-sctp-02.txt>
1959          * or "ADDIP" for short.
1960          */
1961 
1962 
1963 
1964         /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1965          *
1966          * R1) One and only one ASCONF Chunk MAY be in transit and
1967          * unacknowledged at any one time.  If a sender, after sending
1968          * an ASCONF chunk, decides it needs to transfer another
1969          * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1970          * returns from the previous ASCONF Chunk before sending a
1971          * subsequent ASCONF. Note this restriction binds each side,
1972          * so at any time two ASCONF may be in-transit on any given
1973          * association (one sent from each endpoint).
1974          *
1975          * [This is our one-and-only-one ASCONF in flight.  If we do
1976          * not have an ASCONF in flight, this is NULL.]
1977          */
1978         struct sctp_chunk *addip_last_asconf;
1979 
1980         /* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
1981          *
1982          * This is needed to implement itmes E1 - E4 of the updated
1983          * spec.  Here is the justification:
1984          *
1985          * Since the peer may bundle multiple ASCONF chunks toward us,
1986          * we now need the ability to cache multiple ACKs.  The section
1987          * describes in detail how they are cached and cleaned up.
1988          */
1989         struct list_head asconf_ack_list;
1990 
1991         /* These ASCONF chunks are waiting to be sent.
1992          *
1993          * These chunaks can't be pushed to outqueue until receiving
1994          * ASCONF_ACK for the previous ASCONF indicated by
1995          * addip_last_asconf, so as to guarantee that only one ASCONF
1996          * is in flight at any time.
1997          *
1998          * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1999          *
2000          * In defining the ASCONF Chunk transfer procedures, it is
2001          * essential that these transfers MUST NOT cause congestion
2002          * within the network.  To achieve this, we place these
2003          * restrictions on the transfer of ASCONF Chunks:
2004          *
2005          * R1) One and only one ASCONF Chunk MAY be in transit and
2006          * unacknowledged at any one time.  If a sender, after sending
2007          * an ASCONF chunk, decides it needs to transfer another
2008          * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
2009          * returns from the previous ASCONF Chunk before sending a
2010          * subsequent ASCONF. Note this restriction binds each side,
2011          * so at any time two ASCONF may be in-transit on any given
2012          * association (one sent from each endpoint).
2013          *
2014          *
2015          * [I really think this is EXACTLY the sort of intelligence
2016          *  which already resides in sctp_outq.  Please move this
2017          *  queue and its supporting logic down there.  --piggy]
2018          */
2019         struct list_head addip_chunk_list;
2020 
2021         /* ADDIP Section 4.1 ASCONF Chunk Procedures
2022          *
2023          * A2) A serial number should be assigned to the Chunk. The
2024          * serial number SHOULD be a monotonically increasing
2025          * number. The serial number SHOULD be initialized at
2026          * the start of the association to the same value as the
2027          * Initial TSN and every time a new ASCONF chunk is created
2028          * it is incremented by one after assigning the serial number
2029          * to the newly created chunk.
2030          *
2031          * ADDIP
2032          * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
2033          *
2034          * Serial Number : 32 bits (unsigned integer)
2035          *
2036          * This value represents a Serial Number for the ASCONF
2037          * Chunk. The valid range of Serial Number is from 0 to
2038          * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
2039          * after reaching 4294967295.
2040          */
2041         __u32 addip_serial;
2042         int src_out_of_asoc_ok;
2043         union sctp_addr *asconf_addr_del_pending;
2044         struct sctp_transport *new_transport;
2045 
2046         /* SCTP AUTH: list of the endpoint shared keys.  These
2047          * keys are provided out of band by the user applicaton
2048          * and can't change during the lifetime of the association
2049          */
2050         struct list_head endpoint_shared_keys;
2051 
2052         /* SCTP AUTH:
2053          * The current generated assocaition shared key (secret)
2054          */
2055         struct sctp_auth_bytes *asoc_shared_key;
2056         struct sctp_shared_key *shkey;
2057 
2058         /* SCTP AUTH: hmac id of the first peer requested algorithm
2059          * that we support.
2060          */
2061         __u16 default_hmac_id;
2062 
2063         __u16 active_key_id;
2064 
2065         __u8 need_ecne:1,       /* Need to send an ECNE Chunk? */
2066              temp:1,            /* Is it a temporary association? */
2067              force_delay:1,
2068              intl_enable:1,
2069              prsctp_enable:1,
2070              reconf_enable:1;
2071 
2072         __u8 strreset_enable;
2073         __u8 strreset_outstanding; /* request param count on the fly */
2074 
2075         __u32 strreset_outseq; /* Update after receiving response */
2076         __u32 strreset_inseq; /* Update after receiving request */
2077         __u32 strreset_result[2]; /* save the results of last 2 responses */
2078 
2079         struct sctp_chunk *strreset_chunk; /* save request chunk */
2080 
2081         struct sctp_priv_assoc_stats stats;
2082 
2083         int sent_cnt_removable;
2084 
2085         __u16 subscribe;
2086 
2087         __u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
2088         __u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
2089 
2090         struct rcu_head rcu;
2091 };
2092 
2093 
2094 /* An eyecatcher for determining if we are really looking at an
2095  * association data structure.
2096  */
2097 enum {
2098         SCTP_ASSOC_EYECATCHER = 0xa550c123,
2099 };
2100 
2101 /* Recover the outter association structure. */
2102 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
2103 {
2104         struct sctp_association *asoc;
2105 
2106         asoc = container_of(base, struct sctp_association, base);
2107         return asoc;
2108 }
2109 
2110 /* These are function signatures for manipulating associations.  */
2111 
2112 
2113 struct sctp_association *
2114 sctp_association_new(const struct sctp_endpoint *ep, const struct sock *sk,
2115                      enum sctp_scope scope, gfp_t gfp);
2116 void sctp_association_free(struct sctp_association *);
2117 void sctp_association_put(struct sctp_association *);
2118 void sctp_association_hold(struct sctp_association *);
2119 
2120 struct sctp_transport *sctp_assoc_choose_alter_transport(
2121         struct sctp_association *, struct sctp_transport *);
2122 void sctp_assoc_update_retran_path(struct sctp_association *);
2123 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
2124                                           const union sctp_addr *);
2125 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
2126                             const union sctp_addr *laddr);
2127 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
2128                                      const union sctp_addr *address,
2129                                      const gfp_t gfp,
2130                                      const int peer_state);
2131 void sctp_assoc_del_peer(struct sctp_association *asoc,
2132                          const union sctp_addr *addr);
2133 void sctp_assoc_rm_peer(struct sctp_association *asoc,
2134                          struct sctp_transport *peer);
2135 void sctp_assoc_control_transport(struct sctp_association *asoc,
2136                                   struct sctp_transport *transport,
2137                                   enum sctp_transport_cmd command,
2138                                   sctp_sn_error_t error);
2139 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
2140 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
2141 int sctp_assoc_update(struct sctp_association *old,
2142                       struct sctp_association *new);
2143 
2144 __u32 sctp_association_get_next_tsn(struct sctp_association *);
2145 
2146 void sctp_assoc_update_frag_point(struct sctp_association *asoc);
2147 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu);
2148 void sctp_assoc_sync_pmtu(struct sctp_association *asoc);
2149 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
2150 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
2151 void sctp_assoc_set_primary(struct sctp_association *,
2152                             struct sctp_transport *);
2153 void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
2154                                     struct sctp_transport *);
2155 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc,
2156                                      enum sctp_scope scope, gfp_t gfp);
2157 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
2158                                          struct sctp_cookie*,
2159                                          gfp_t gfp);
2160 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
2161 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
2162 struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
2163                                         const struct sctp_association *asoc,
2164                                         __be32 serial);
2165 void sctp_asconf_queue_teardown(struct sctp_association *asoc);
2166 
2167 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
2168                         const union sctp_addr *ss2);
2169 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
2170 
2171 /* A convenience structure to parse out SCTP specific CMSGs. */
2172 struct sctp_cmsgs {
2173         struct sctp_initmsg *init;
2174         struct sctp_sndrcvinfo *srinfo;
2175         struct sctp_sndinfo *sinfo;
2176         struct sctp_prinfo *prinfo;
2177         struct sctp_authinfo *authinfo;
2178         struct msghdr *addrs_msg;
2179 };
2180 
2181 /* Structure for tracking memory objects */
2182 struct sctp_dbg_objcnt_entry {
2183         char *label;
2184         atomic_t *counter;
2185 };
2186 
2187 #endif /* __sctp_structs_h__ */
2188 

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