include/net/sctp/sctp.h

   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) 2001-2003 Intel Corp.
   6  *
   7  * This file is part of the SCTP kernel implementation
   8  *
   9  * The base lksctp header.
  10  *
  11  * This SCTP implementation is free software;
  12  * you can redistribute it and/or modify it under the terms of
  13  * the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2, or (at your option)
  15  * any later version.
  16  *
  17  * This SCTP implementation is distributed in the hope that it
  18  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  19  *                 ************************
  20  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  21  * See the GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with GNU CC; see the file COPYING.  If not, see
  25  * <http://www.gnu.org/licenses/>.
  26  *
  27  * Please send any bug reports or fixes you make to the
  28  * email address(es):
  29  *    lksctp developers <linux-sctp@vger.kernel.org>
  30  *
  31  * Written or modified by:
  32  *    La Monte H.P. Yarroll <piggy@acm.org>
  33  *    Xingang Guo           <xingang.guo@intel.com>
  34  *    Jon Grimm             <jgrimm@us.ibm.com>
  35  *    Daisy Chang           <daisyc@us.ibm.com>
  36  *    Sridhar Samudrala     <sri@us.ibm.com>
  37  *    Ardelle Fan           <ardelle.fan@intel.com>
  38  *    Ryan Layer            <rmlayer@us.ibm.com>
  39  *    Kevin Gao             <kevin.gao@intel.com>
  40  */
  41
  42 #ifndef __net_sctp_h__
  43 #define __net_sctp_h__
  44
  45 /* Header Strategy.
  46  *    Start getting some control over the header file depencies:
  47  *       includes
  48  *       constants
  49  *       structs
  50  *       prototypes
  51  *       macros, externs, and inlines
  52  *
  53  *   Move test_frame specific items out of the kernel headers
  54  *   and into the test frame headers.   This is not perfect in any sense
  55  *   and will continue to evolve.
  56  */
  57
  58 #include <linux/types.h>
  59 #include <linux/slab.h>
  60 #include <linux/in.h>
  61 #include <linux/tty.h>
  62 #include <linux/proc_fs.h>
  63 #include <linux/spinlock.h>
  64 #include <linux/jiffies.h>
  65 #include <linux/idr.h>
  66
  67 #if IS_ENABLED(CONFIG_IPV6)
  68 #include <net/ipv6.h>
  69 #include <net/ip6_route.h>
  70 #endif
  71
  72 #include <linux/uaccess.h>
  73 #include <asm/page.h>
  74 #include <net/sock.h>
  75 #include <net/snmp.h>
  76 #include <net/sctp/structs.h>
  77 #include <net/sctp/constants.h>
  78
  79 #ifdef CONFIG_IP_SCTP_MODULE
  80 #define SCTP_PROTOSW_FLAG 0
  81 #else /* static! */
  82 #define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
  83 #endif
  84
  85 /* Round an int up to the next multiple of 4.  */
  86 #define SCTP_PAD4(s) (((s)+3)&~3)
  87 /* Truncate to the previous multiple of 4.  */
  88 #define SCTP_TRUNC4(s) ((s)&~3)
  89
  90 /*
  91  * Function declarations.
  92  */
  93
  94 /*
  95  * sctp/protocol.c
  96  */
  97 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *addr,
  98                               enum sctp_scope, gfp_t gfp, int flags);
  99 struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
 100 int sctp_register_pf(struct sctp_pf *, sa_family_t);
 101 void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
 102
 103 /*
 104  * sctp/socket.c
 105  */
 106 int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
 107                       int addr_len, int flags);
 108 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
 109 int sctp_inet_listen(struct socket *sock, int backlog);
 110 void sctp_write_space(struct sock *sk);
 111 void sctp_data_ready(struct sock *sk);
 112 __poll_t sctp_poll(struct file *file, struct socket *sock,
 113                 poll_table *wait);
 114 void sctp_sock_rfree(struct sk_buff *skb);
 115 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 116                     struct sctp_association *asoc);
 117 extern struct percpu_counter sctp_sockets_allocated;
 118 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
 119 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
 120
 121 void sctp_transport_walk_start(struct rhashtable_iter *iter);
 122 void sctp_transport_walk_stop(struct rhashtable_iter *iter);
 123 struct sctp_transport *sctp_transport_get_next(struct net *net,
 124                         struct rhashtable_iter *iter);
 125 struct sctp_transport *sctp_transport_get_idx(struct net *net,
 126                         struct rhashtable_iter *iter, int pos);
 127 int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
 128                                   struct net *net,
 129                                   const union sctp_addr *laddr,
 130                                   const union sctp_addr *paddr, void *p);
 131 int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
 132                             int (*cb_done)(struct sctp_transport *, void *),
 133                             struct net *net, int *pos, void *p);
 134 int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p);
 135 int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
 136                        struct sctp_info *info);
 137
 138 /*
 139  * sctp/primitive.c
 140  */
 141 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
 142 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
 143 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
 144 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
 145 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
 146 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
 147 int sctp_primitive_RECONF(struct net *net, struct sctp_association *asoc,
 148                           void *arg);
 149
 150 /*
 151  * sctp/input.c
 152  */
 153 int sctp_rcv(struct sk_buff *skb);
 154 int sctp_v4_err(struct sk_buff *skb, u32 info);
 155 int sctp_hash_endpoint(struct sctp_endpoint *ep);
 156 void sctp_unhash_endpoint(struct sctp_endpoint *);
 157 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
 158                              struct sctphdr *, struct sctp_association **,
 159                              struct sctp_transport **);
 160 void sctp_err_finish(struct sock *, struct sctp_transport *);
 161 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
 162                            struct sctp_transport *t, __u32 pmtu);
 163 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
 164                         struct sk_buff *);
 165 void sctp_icmp_proto_unreachable(struct sock *sk,
 166                                  struct sctp_association *asoc,
 167                                  struct sctp_transport *t);
 168 void sctp_backlog_migrate(struct sctp_association *assoc,
 169                           struct sock *oldsk, struct sock *newsk);
 170 int sctp_transport_hashtable_init(void);
 171 void sctp_transport_hashtable_destroy(void);
 172 int sctp_hash_transport(struct sctp_transport *t);
 173 void sctp_unhash_transport(struct sctp_transport *t);
 174 struct sctp_transport *sctp_addrs_lookup_transport(
 175                                 struct net *net,
 176                                 const union sctp_addr *laddr,
 177                                 const union sctp_addr *paddr);
 178 struct sctp_transport *sctp_epaddr_lookup_transport(
 179                                 const struct sctp_endpoint *ep,
 180                                 const union sctp_addr *paddr);
 181
 182 /*
 183  * sctp/proc.c
 184  */
 185 int __net_init sctp_proc_init(struct net *net);
 186
 187 /*
 188  * sctp/offload.c
 189  */
 190 int sctp_offload_init(void);
 191
 192 /*
 193  * sctp/stream_sched.c
 194  */
 195 void sctp_sched_ops_init(void);
 196
 197 /*
 198  * sctp/stream.c
 199  */
 200 int sctp_send_reset_streams(struct sctp_association *asoc,
 201                             struct sctp_reset_streams *params);
 202 int sctp_send_reset_assoc(struct sctp_association *asoc);
 203 int sctp_send_add_streams(struct sctp_association *asoc,
 204                           struct sctp_add_streams *params);
 205
 206 /*
 207  * Module global variables
 208  */
 209
 210  /*
 211   * sctp/protocol.c
 212   */
 213 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
 214 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
 215 extern long sysctl_sctp_mem[3];
 216 extern int sysctl_sctp_rmem[3];
 217 extern int sysctl_sctp_wmem[3];
 218
 219 /*
 220  *  Section:  Macros, externs, and inlines
 221  */
 222
 223 /* SCTP SNMP MIB stats handlers */
 224 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
 225 #define __SCTP_INC_STATS(net, field)    __SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
 226 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
 227
 228 /* sctp mib definitions */
 229 enum {
 230         SCTP_MIB_NUM = 0,
 231         SCTP_MIB_CURRESTAB,                     /* CurrEstab */
 232         SCTP_MIB_ACTIVEESTABS,                  /* ActiveEstabs */
 233         SCTP_MIB_PASSIVEESTABS,                 /* PassiveEstabs */
 234         SCTP_MIB_ABORTEDS,                      /* Aborteds */
 235         SCTP_MIB_SHUTDOWNS,                     /* Shutdowns */
 236         SCTP_MIB_OUTOFBLUES,                    /* OutOfBlues */
 237         SCTP_MIB_CHECKSUMERRORS,                /* ChecksumErrors */
 238         SCTP_MIB_OUTCTRLCHUNKS,                 /* OutCtrlChunks */
 239         SCTP_MIB_OUTORDERCHUNKS,                /* OutOrderChunks */
 240         SCTP_MIB_OUTUNORDERCHUNKS,              /* OutUnorderChunks */
 241         SCTP_MIB_INCTRLCHUNKS,                  /* InCtrlChunks */
 242         SCTP_MIB_INORDERCHUNKS,                 /* InOrderChunks */
 243         SCTP_MIB_INUNORDERCHUNKS,               /* InUnorderChunks */
 244         SCTP_MIB_FRAGUSRMSGS,                   /* FragUsrMsgs */
 245         SCTP_MIB_REASMUSRMSGS,                  /* ReasmUsrMsgs */
 246         SCTP_MIB_OUTSCTPPACKS,                  /* OutSCTPPacks */
 247         SCTP_MIB_INSCTPPACKS,                   /* InSCTPPacks */
 248         SCTP_MIB_T1_INIT_EXPIREDS,
 249         SCTP_MIB_T1_COOKIE_EXPIREDS,
 250         SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
 251         SCTP_MIB_T3_RTX_EXPIREDS,
 252         SCTP_MIB_T4_RTO_EXPIREDS,
 253         SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
 254         SCTP_MIB_DELAY_SACK_EXPIREDS,
 255         SCTP_MIB_AUTOCLOSE_EXPIREDS,
 256         SCTP_MIB_T1_RETRANSMITS,
 257         SCTP_MIB_T3_RETRANSMITS,
 258         SCTP_MIB_PMTUD_RETRANSMITS,
 259         SCTP_MIB_FAST_RETRANSMITS,
 260         SCTP_MIB_IN_PKT_SOFTIRQ,
 261         SCTP_MIB_IN_PKT_BACKLOG,
 262         SCTP_MIB_IN_PKT_DISCARDS,
 263         SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
 264         __SCTP_MIB_MAX
 265 };
 266
 267 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
 268 struct sctp_mib {
 269         unsigned long   mibs[SCTP_MIB_MAX];
 270 };
 271
 272 /* helper function to track stats about max rto and related transport */
 273 static inline void sctp_max_rto(struct sctp_association *asoc,
 274                                 struct sctp_transport *trans)
 275 {
 276         if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
 277                 asoc->stats.max_obs_rto = trans->rto;
 278                 memset(&asoc->stats.obs_rto_ipaddr, 0,
 279                         sizeof(struct sockaddr_storage));
 280                 memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
 281                         trans->af_specific->sockaddr_len);
 282         }
 283 }
 284
 285 /*
 286  * Macros for keeping a global reference of object allocations.
 287  */
 288 #ifdef CONFIG_SCTP_DBG_OBJCNT
 289
 290 extern atomic_t sctp_dbg_objcnt_sock;
 291 extern atomic_t sctp_dbg_objcnt_ep;
 292 extern atomic_t sctp_dbg_objcnt_assoc;
 293 extern atomic_t sctp_dbg_objcnt_transport;
 294 extern atomic_t sctp_dbg_objcnt_chunk;
 295 extern atomic_t sctp_dbg_objcnt_bind_addr;
 296 extern atomic_t sctp_dbg_objcnt_bind_bucket;
 297 extern atomic_t sctp_dbg_objcnt_addr;
 298 extern atomic_t sctp_dbg_objcnt_datamsg;
 299 extern atomic_t sctp_dbg_objcnt_keys;
 300
 301 /* Macros to atomically increment/decrement objcnt counters.  */
 302 #define SCTP_DBG_OBJCNT_INC(name) \
 303 atomic_inc(&sctp_dbg_objcnt_## name)
 304 #define SCTP_DBG_OBJCNT_DEC(name) \
 305 atomic_dec(&sctp_dbg_objcnt_## name)
 306 #define SCTP_DBG_OBJCNT(name) \
 307 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
 308
 309 /* Macro to help create new entries in in the global array of
 310  * objcnt counters.
 311  */
 312 #define SCTP_DBG_OBJCNT_ENTRY(name) \
 313 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
 314
 315 void sctp_dbg_objcnt_init(struct net *);
 316
 317 #else
 318
 319 #define SCTP_DBG_OBJCNT_INC(name)
 320 #define SCTP_DBG_OBJCNT_DEC(name)
 321
 322 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
 323
 324 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
 325
 326 #if defined CONFIG_SYSCTL
 327 void sctp_sysctl_register(void);
 328 void sctp_sysctl_unregister(void);
 329 int sctp_sysctl_net_register(struct net *net);
 330 void sctp_sysctl_net_unregister(struct net *net);
 331 #else
 332 static inline void sctp_sysctl_register(void) { return; }
 333 static inline void sctp_sysctl_unregister(void) { return; }
 334 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
 335 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
 336 #endif
 337
 338 /* Size of Supported Address Parameter for 'x' address types. */
 339 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
 340
 341 #if IS_ENABLED(CONFIG_IPV6)
 342
 343 void sctp_v6_pf_init(void);
 344 void sctp_v6_pf_exit(void);
 345 int sctp_v6_protosw_init(void);
 346 void sctp_v6_protosw_exit(void);
 347 int sctp_v6_add_protocol(void);
 348 void sctp_v6_del_protocol(void);
 349
 350 #else /* #ifdef defined(CONFIG_IPV6) */
 351
 352 static inline void sctp_v6_pf_init(void) { return; }
 353 static inline void sctp_v6_pf_exit(void) { return; }
 354 static inline int sctp_v6_protosw_init(void) { return 0; }
 355 static inline void sctp_v6_protosw_exit(void) { return; }
 356 static inline int sctp_v6_add_protocol(void) { return 0; }
 357 static inline void sctp_v6_del_protocol(void) { return; }
 358
 359 #endif /* #if defined(CONFIG_IPV6) */
 360
 361
 362 /* Map an association to an assoc_id. */
 363 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
 364 {
 365         return asoc ? asoc->assoc_id : 0;
 366 }
 367
 368 static inline enum sctp_sstat_state
 369 sctp_assoc_to_state(const struct sctp_association *asoc)
 370 {
 371         /* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
 372          * got rid of it in kernel space. Therefore SCTP_CLOSED et al
 373          * start at =1 in user space, but actually as =0 in kernel space.
 374          * Now that we can not break user space and SCTP_EMPTY is exposed
 375          * there, we need to fix it up with an ugly offset not to break
 376          * applications. :(
 377          */
 378         return asoc->state + 1;
 379 }
 380
 381 /* Look up the association by its id.  */
 382 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
 383
 384 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
 385
 386 /* A macro to walk a list of skbs.  */
 387 #define sctp_skb_for_each(pos, head, tmp) \
 388         skb_queue_walk_safe(head, pos, tmp)
 389
 390 /**
 391  *      sctp_list_dequeue - remove from the head of the queue
 392  *      @list: list to dequeue from
 393  *
 394  *      Remove the head of the list. The head item is
 395  *      returned or %NULL if the list is empty.
 396  */
 397
 398 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
 399 {
 400         struct list_head *result = NULL;
 401
 402         if (!list_empty(list)) {
 403                 result = list->next;
 404                 list_del_init(result);
 405         }
 406         return result;
 407 }
 408
 409 /* SCTP version of skb_set_owner_r.  We need this one because
 410  * of the way we have to do receive buffer accounting on bundled
 411  * chunks.
 412  */
 413 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
 414 {
 415         struct sctp_ulpevent *event = sctp_skb2event(skb);
 416
 417         skb_orphan(skb);
 418         skb->sk = sk;
 419         skb->destructor = sctp_sock_rfree;
 420         atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
 421         /*
 422          * This mimics the behavior of skb_set_owner_r
 423          */
 424         sk->sk_forward_alloc -= event->rmem_len;
 425 }
 426
 427 /* Tests if the list has one and only one entry. */
 428 static inline int sctp_list_single_entry(struct list_head *head)
 429 {
 430         return (head->next != head) && (head->next == head->prev);
 431 }
 432
 433 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
 434 {
 435         return !list_empty(&chunk->list);
 436 }
 437
 438 /* Walk through a list of TLV parameters.  Don't trust the
 439  * individual parameter lengths and instead depend on
 440  * the chunk length to indicate when to stop.  Make sure
 441  * there is room for a param header too.
 442  */
 443 #define sctp_walk_params(pos, chunk, member)\
 444 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
 445
 446 #define _sctp_walk_params(pos, chunk, end, member)\
 447 for (pos.v = chunk->member;\
 448      (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <=\
 449       (void *)chunk + end) &&\
 450      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
 451      ntohs(pos.p->length) >= sizeof(struct sctp_paramhdr);\
 452      pos.v += SCTP_PAD4(ntohs(pos.p->length)))
 453
 454 #define sctp_walk_errors(err, chunk_hdr)\
 455 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
 456
 457 #define _sctp_walk_errors(err, chunk_hdr, end)\
 458 for (err = (struct sctp_errhdr *)((void *)chunk_hdr + \
 459             sizeof(struct sctp_chunkhdr));\
 460      ((void *)err + offsetof(struct sctp_errhdr, length) + sizeof(err->length) <=\
 461       (void *)chunk_hdr + end) &&\
 462      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
 463      ntohs(err->length) >= sizeof(struct sctp_errhdr); \
 464      err = (struct sctp_errhdr *)((void *)err + SCTP_PAD4(ntohs(err->length))))
 465
 466 #define sctp_walk_fwdtsn(pos, chunk)\
 467 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
 468
 469 #define _sctp_walk_fwdtsn(pos, chunk, end)\
 470 for (pos = chunk->subh.fwdtsn_hdr->skip;\
 471      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
 472      pos++)
 473
 474 /* External references. */
 475
 476 extern struct proto sctp_prot;
 477 extern struct proto sctpv6_prot;
 478 void sctp_put_port(struct sock *sk);
 479
 480 extern struct idr sctp_assocs_id;
 481 extern spinlock_t sctp_assocs_id_lock;
 482
 483 /* Static inline functions. */
 484
 485 /* Convert from an IP version number to an Address Family symbol.  */
 486 static inline int ipver2af(__u8 ipver)
 487 {
 488         switch (ipver) {
 489         case 4:
 490                 return  AF_INET;
 491         case 6:
 492                 return AF_INET6;
 493         default:
 494                 return 0;
 495         }
 496 }
 497
 498 /* Convert from an address parameter type to an address family.  */
 499 static inline int param_type2af(__be16 type)
 500 {
 501         switch (type) {
 502         case SCTP_PARAM_IPV4_ADDRESS:
 503                 return  AF_INET;
 504         case SCTP_PARAM_IPV6_ADDRESS:
 505                 return AF_INET6;
 506         default:
 507                 return 0;
 508         }
 509 }
 510
 511 /* Warning: The following hash functions assume a power of two 'size'. */
 512 /* This is the hash function for the SCTP port hash table. */
 513 static inline int sctp_phashfn(struct net *net, __u16 lport)
 514 {
 515         return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
 516 }
 517
 518 /* This is the hash function for the endpoint hash table. */
 519 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
 520 {
 521         return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
 522 }
 523
 524 #define sctp_for_each_hentry(epb, head) \
 525         hlist_for_each_entry(epb, head, node)
 526
 527 /* Is a socket of this style? */
 528 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
 529 static inline int __sctp_style(const struct sock *sk,
 530                                enum sctp_socket_type style)
 531 {
 532         return sctp_sk(sk)->type == style;
 533 }
 534
 535 /* Is the association in this state? */
 536 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
 537 static inline int __sctp_state(const struct sctp_association *asoc,
 538                                enum sctp_state state)
 539 {
 540         return asoc->state == state;
 541 }
 542
 543 /* Is the socket in this state? */
 544 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
 545 static inline int __sctp_sstate(const struct sock *sk,
 546                                 enum sctp_sock_state state)
 547 {
 548         return sk->sk_state == state;
 549 }
 550
 551 /* Map v4-mapped v6 address back to v4 address */
 552 static inline void sctp_v6_map_v4(union sctp_addr *addr)
 553 {
 554         addr->v4.sin_family = AF_INET;
 555         addr->v4.sin_port = addr->v6.sin6_port;
 556         addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
 557 }
 558
 559 /* Map v4 address to v4-mapped v6 address */
 560 static inline void sctp_v4_map_v6(union sctp_addr *addr)
 561 {
 562         __be16 port;
 563
 564         port = addr->v4.sin_port;
 565         addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
 566         addr->v6.sin6_port = port;
 567         addr->v6.sin6_family = AF_INET6;
 568         addr->v6.sin6_flowinfo = 0;
 569         addr->v6.sin6_scope_id = 0;
 570         addr->v6.sin6_addr.s6_addr32[0] = 0;
 571         addr->v6.sin6_addr.s6_addr32[1] = 0;
 572         addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
 573 }
 574
 575 /* The cookie is always 0 since this is how it's used in the
 576  * pmtu code.
 577  */
 578 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
 579 {
 580         if (t->dst && !dst_check(t->dst, t->dst_cookie))
 581                 sctp_transport_dst_release(t);
 582
 583         return t->dst;
 584 }
 585
 586 /* Calculate max payload size given a MTU, or the total overhead if
 587  * given MTU is zero
 588  */
 589 static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
 590                                      __u32 mtu, __u32 extra)
 591 {
 592         __u32 overhead = sizeof(struct sctphdr) + extra;
 593
 594         if (sp)
 595                 overhead += sp->pf->af->net_header_len;
 596         else
 597                 overhead += sizeof(struct ipv6hdr);
 598
 599         if (WARN_ON_ONCE(mtu && mtu <= overhead))
 600                 mtu = overhead;
 601
 602         return mtu ? mtu - overhead : overhead;
 603 }
 604
 605 static inline __u32 sctp_dst_mtu(const struct dst_entry *dst)
 606 {
 607         return SCTP_TRUNC4(max_t(__u32, dst_mtu(dst),
 608                                  SCTP_DEFAULT_MINSEGMENT));
 609 }
 610
 611 static inline bool sctp_transport_pmtu_check(struct sctp_transport *t)
 612 {
 613         __u32 pmtu = sctp_dst_mtu(t->dst);
 614
 615         if (t->pathmtu == pmtu)
 616                 return true;
 617
 618         t->pathmtu = pmtu;
 619
 620         return false;
 621 }
 622
 623 static inline __u32 sctp_min_frag_point(struct sctp_sock *sp, __u16 datasize)
 624 {
 625         return sctp_mtu_payload(sp, SCTP_DEFAULT_MINSEGMENT, datasize);
 626 }
 627
 628 #endif /* __net_sctp_h__ */