include/net/sctp/sctp.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* SCTP kernel implementation
   3  * (C) Copyright IBM Corp. 2001, 2004
   4  * Copyright (c) 1999-2000 Cisco, Inc.
   5  * Copyright (c) 1999-2001 Motorola, Inc.
   6  * Copyright (c) 2001-2003 Intel Corp.
   7  *
   8  * This file is part of the SCTP kernel implementation
   9  *
  10  * The base lksctp header.
  11  *
  12  * Please send any bug reports or fixes you make to the
  13  * email address(es):
  14  *    lksctp developers <linux-sctp@vger.kernel.org>
  15  *
  16  * Written or modified by:
  17  *    La Monte H.P. Yarroll <piggy@acm.org>
  18  *    Xingang Guo           <xingang.guo@intel.com>
  19  *    Jon Grimm             <jgrimm@us.ibm.com>
  20  *    Daisy Chang           <daisyc@us.ibm.com>
  21  *    Sridhar Samudrala     <sri@us.ibm.com>
  22  *    Ardelle Fan           <ardelle.fan@intel.com>
  23  *    Ryan Layer            <rmlayer@us.ibm.com>
  24  *    Kevin Gao             <kevin.gao@intel.com>
  25  */
  26
  27 #ifndef __net_sctp_h__
  28 #define __net_sctp_h__
  29
  30 /* Header Strategy.
  31  *    Start getting some control over the header file depencies:
  32  *       includes
  33  *       constants
  34  *       structs
  35  *       prototypes
  36  *       macros, externs, and inlines
  37  *
  38  *   Move test_frame specific items out of the kernel headers
  39  *   and into the test frame headers.   This is not perfect in any sense
  40  *   and will continue to evolve.
  41  */
  42
  43 #include <linux/types.h>
  44 #include <linux/slab.h>
  45 #include <linux/in.h>
  46 #include <linux/tty.h>
  47 #include <linux/proc_fs.h>
  48 #include <linux/spinlock.h>
  49 #include <linux/jiffies.h>
  50 #include <linux/idr.h>
  51
  52 #if IS_ENABLED(CONFIG_IPV6)
  53 #include <net/ipv6.h>
  54 #include <net/ip6_route.h>
  55 #endif
  56
  57 #include <linux/uaccess.h>
  58 #include <asm/page.h>
  59 #include <net/sock.h>
  60 #include <net/snmp.h>
  61 #include <net/sctp/structs.h>
  62 #include <net/sctp/constants.h>
  63
  64 #ifdef CONFIG_IP_SCTP_MODULE
  65 #define SCTP_PROTOSW_FLAG 0
  66 #else /* static! */
  67 #define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
  68 #endif
  69
  70 /* Round an int up to the next multiple of 4.  */
  71 #define SCTP_PAD4(s) (((s)+3)&~3)
  72 /* Truncate to the previous multiple of 4.  */
  73 #define SCTP_TRUNC4(s) ((s)&~3)
  74
  75 /*
  76  * Function declarations.
  77  */
  78
  79 /*
  80  * sctp/protocol.c
  81  */
  82 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *addr,
  83                               enum sctp_scope, gfp_t gfp, int flags);
  84 struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
  85 int sctp_register_pf(struct sctp_pf *, sa_family_t);
  86 void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
  87
  88 /*
  89  * sctp/socket.c
  90  */
  91 int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
  92                       int addr_len, int flags);
  93 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
  94 int sctp_inet_listen(struct socket *sock, int backlog);
  95 void sctp_write_space(struct sock *sk);
  96 void sctp_data_ready(struct sock *sk);
  97 __poll_t sctp_poll(struct file *file, struct socket *sock,
  98                 poll_table *wait);
  99 void sctp_sock_rfree(struct sk_buff *skb);
 100 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 101                     struct sctp_association *asoc);
 102 extern struct percpu_counter sctp_sockets_allocated;
 103 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
 104 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
 105
 106 void sctp_transport_walk_start(struct rhashtable_iter *iter);
 107 void sctp_transport_walk_stop(struct rhashtable_iter *iter);
 108 struct sctp_transport *sctp_transport_get_next(struct net *net,
 109                         struct rhashtable_iter *iter);
 110 struct sctp_transport *sctp_transport_get_idx(struct net *net,
 111                         struct rhashtable_iter *iter, int pos);
 112 int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
 113                                   struct net *net,
 114                                   const union sctp_addr *laddr,
 115                                   const union sctp_addr *paddr, void *p);
 116 int sctp_for_each_transport(int (*cb)(struct sctp_transport *, void *),
 117                             int (*cb_done)(struct sctp_transport *, void *),
 118                             struct net *net, int *pos, void *p);
 119 int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p);
 120 int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
 121                        struct sctp_info *info);
 122
 123 /*
 124  * sctp/primitive.c
 125  */
 126 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
 127 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
 128 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
 129 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
 130 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
 131 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
 132 int sctp_primitive_RECONF(struct net *net, struct sctp_association *asoc,
 133                           void *arg);
 134
 135 /*
 136  * sctp/input.c
 137  */
 138 int sctp_rcv(struct sk_buff *skb);
 139 int sctp_v4_err(struct sk_buff *skb, u32 info);
 140 int sctp_hash_endpoint(struct sctp_endpoint *ep);
 141 void sctp_unhash_endpoint(struct sctp_endpoint *);
 142 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
 143                              struct sctphdr *, struct sctp_association **,
 144                              struct sctp_transport **);
 145 void sctp_err_finish(struct sock *, struct sctp_transport *);
 146 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
 147                            struct sctp_transport *t, __u32 pmtu);
 148 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
 149                         struct sk_buff *);
 150 void sctp_icmp_proto_unreachable(struct sock *sk,
 151                                  struct sctp_association *asoc,
 152                                  struct sctp_transport *t);
 153 void sctp_backlog_migrate(struct sctp_association *assoc,
 154                           struct sock *oldsk, struct sock *newsk);
 155 int sctp_transport_hashtable_init(void);
 156 void sctp_transport_hashtable_destroy(void);
 157 int sctp_hash_transport(struct sctp_transport *t);
 158 void sctp_unhash_transport(struct sctp_transport *t);
 159 struct sctp_transport *sctp_addrs_lookup_transport(
 160                                 struct net *net,
 161                                 const union sctp_addr *laddr,
 162                                 const union sctp_addr *paddr);
 163 struct sctp_transport *sctp_epaddr_lookup_transport(
 164                                 const struct sctp_endpoint *ep,
 165                                 const union sctp_addr *paddr);
 166
 167 /*
 168  * sctp/proc.c
 169  */
 170 int __net_init sctp_proc_init(struct net *net);
 171
 172 /*
 173  * sctp/offload.c
 174  */
 175 int sctp_offload_init(void);
 176
 177 /*
 178  * sctp/stream_sched.c
 179  */
 180 void sctp_sched_ops_init(void);
 181
 182 /*
 183  * sctp/stream.c
 184  */
 185 int sctp_send_reset_streams(struct sctp_association *asoc,
 186                             struct sctp_reset_streams *params);
 187 int sctp_send_reset_assoc(struct sctp_association *asoc);
 188 int sctp_send_add_streams(struct sctp_association *asoc,
 189                           struct sctp_add_streams *params);
 190
 191 /*
 192  * Module global variables
 193  */
 194
 195  /*
 196   * sctp/protocol.c
 197   */
 198 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
 199 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
 200 extern long sysctl_sctp_mem[3];
 201 extern int sysctl_sctp_rmem[3];
 202 extern int sysctl_sctp_wmem[3];
 203
 204 /*
 205  *  Section:  Macros, externs, and inlines
 206  */
 207
 208 /* SCTP SNMP MIB stats handlers */
 209 #define SCTP_INC_STATS(net, field)      SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
 210 #define __SCTP_INC_STATS(net, field)    __SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
 211 #define SCTP_DEC_STATS(net, field)      SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
 212
 213 /* sctp mib definitions */
 214 enum {
 215         SCTP_MIB_NUM = 0,
 216         SCTP_MIB_CURRESTAB,                     /* CurrEstab */
 217         SCTP_MIB_ACTIVEESTABS,                  /* ActiveEstabs */
 218         SCTP_MIB_PASSIVEESTABS,                 /* PassiveEstabs */
 219         SCTP_MIB_ABORTEDS,                      /* Aborteds */
 220         SCTP_MIB_SHUTDOWNS,                     /* Shutdowns */
 221         SCTP_MIB_OUTOFBLUES,                    /* OutOfBlues */
 222         SCTP_MIB_CHECKSUMERRORS,                /* ChecksumErrors */
 223         SCTP_MIB_OUTCTRLCHUNKS,                 /* OutCtrlChunks */
 224         SCTP_MIB_OUTORDERCHUNKS,                /* OutOrderChunks */
 225         SCTP_MIB_OUTUNORDERCHUNKS,              /* OutUnorderChunks */
 226         SCTP_MIB_INCTRLCHUNKS,                  /* InCtrlChunks */
 227         SCTP_MIB_INORDERCHUNKS,                 /* InOrderChunks */
 228         SCTP_MIB_INUNORDERCHUNKS,               /* InUnorderChunks */
 229         SCTP_MIB_FRAGUSRMSGS,                   /* FragUsrMsgs */
 230         SCTP_MIB_REASMUSRMSGS,                  /* ReasmUsrMsgs */
 231         SCTP_MIB_OUTSCTPPACKS,                  /* OutSCTPPacks */
 232         SCTP_MIB_INSCTPPACKS,                   /* InSCTPPacks */
 233         SCTP_MIB_T1_INIT_EXPIREDS,
 234         SCTP_MIB_T1_COOKIE_EXPIREDS,
 235         SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
 236         SCTP_MIB_T3_RTX_EXPIREDS,
 237         SCTP_MIB_T4_RTO_EXPIREDS,
 238         SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
 239         SCTP_MIB_DELAY_SACK_EXPIREDS,
 240         SCTP_MIB_AUTOCLOSE_EXPIREDS,
 241         SCTP_MIB_T1_RETRANSMITS,
 242         SCTP_MIB_T3_RETRANSMITS,
 243         SCTP_MIB_PMTUD_RETRANSMITS,
 244         SCTP_MIB_FAST_RETRANSMITS,
 245         SCTP_MIB_IN_PKT_SOFTIRQ,
 246         SCTP_MIB_IN_PKT_BACKLOG,
 247         SCTP_MIB_IN_PKT_DISCARDS,
 248         SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
 249         __SCTP_MIB_MAX
 250 };
 251
 252 #define SCTP_MIB_MAX    __SCTP_MIB_MAX
 253 struct sctp_mib {
 254         unsigned long   mibs[SCTP_MIB_MAX];
 255 };
 256
 257 /* helper function to track stats about max rto and related transport */
 258 static inline void sctp_max_rto(struct sctp_association *asoc,
 259                                 struct sctp_transport *trans)
 260 {
 261         if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
 262                 asoc->stats.max_obs_rto = trans->rto;
 263                 memset(&asoc->stats.obs_rto_ipaddr, 0,
 264                         sizeof(struct sockaddr_storage));
 265                 memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
 266                         trans->af_specific->sockaddr_len);
 267         }
 268 }
 269
 270 /*
 271  * Macros for keeping a global reference of object allocations.
 272  */
 273 #ifdef CONFIG_SCTP_DBG_OBJCNT
 274
 275 extern atomic_t sctp_dbg_objcnt_sock;
 276 extern atomic_t sctp_dbg_objcnt_ep;
 277 extern atomic_t sctp_dbg_objcnt_assoc;
 278 extern atomic_t sctp_dbg_objcnt_transport;
 279 extern atomic_t sctp_dbg_objcnt_chunk;
 280 extern atomic_t sctp_dbg_objcnt_bind_addr;
 281 extern atomic_t sctp_dbg_objcnt_bind_bucket;
 282 extern atomic_t sctp_dbg_objcnt_addr;
 283 extern atomic_t sctp_dbg_objcnt_datamsg;
 284 extern atomic_t sctp_dbg_objcnt_keys;
 285
 286 /* Macros to atomically increment/decrement objcnt counters.  */
 287 #define SCTP_DBG_OBJCNT_INC(name) \
 288 atomic_inc(&sctp_dbg_objcnt_## name)
 289 #define SCTP_DBG_OBJCNT_DEC(name) \
 290 atomic_dec(&sctp_dbg_objcnt_## name)
 291 #define SCTP_DBG_OBJCNT(name) \
 292 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
 293
 294 /* Macro to help create new entries in in the global array of
 295  * objcnt counters.
 296  */
 297 #define SCTP_DBG_OBJCNT_ENTRY(name) \
 298 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
 299
 300 void sctp_dbg_objcnt_init(struct net *);
 301
 302 #else
 303
 304 #define SCTP_DBG_OBJCNT_INC(name)
 305 #define SCTP_DBG_OBJCNT_DEC(name)
 306
 307 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
 308
 309 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
 310
 311 #if defined CONFIG_SYSCTL
 312 void sctp_sysctl_register(void);
 313 void sctp_sysctl_unregister(void);
 314 int sctp_sysctl_net_register(struct net *net);
 315 void sctp_sysctl_net_unregister(struct net *net);
 316 #else
 317 static inline void sctp_sysctl_register(void) { return; }
 318 static inline void sctp_sysctl_unregister(void) { return; }
 319 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
 320 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
 321 #endif
 322
 323 /* Size of Supported Address Parameter for 'x' address types. */
 324 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
 325
 326 #if IS_ENABLED(CONFIG_IPV6)
 327
 328 void sctp_v6_pf_init(void);
 329 void sctp_v6_pf_exit(void);
 330 int sctp_v6_protosw_init(void);
 331 void sctp_v6_protosw_exit(void);
 332 int sctp_v6_add_protocol(void);
 333 void sctp_v6_del_protocol(void);
 334
 335 #else /* #ifdef defined(CONFIG_IPV6) */
 336
 337 static inline void sctp_v6_pf_init(void) { return; }
 338 static inline void sctp_v6_pf_exit(void) { return; }
 339 static inline int sctp_v6_protosw_init(void) { return 0; }
 340 static inline void sctp_v6_protosw_exit(void) { return; }
 341 static inline int sctp_v6_add_protocol(void) { return 0; }
 342 static inline void sctp_v6_del_protocol(void) { return; }
 343
 344 #endif /* #if defined(CONFIG_IPV6) */
 345
 346
 347 /* Map an association to an assoc_id. */
 348 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
 349 {
 350         return asoc ? asoc->assoc_id : 0;
 351 }
 352
 353 static inline enum sctp_sstat_state
 354 sctp_assoc_to_state(const struct sctp_association *asoc)
 355 {
 356         /* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
 357          * got rid of it in kernel space. Therefore SCTP_CLOSED et al
 358          * start at =1 in user space, but actually as =0 in kernel space.
 359          * Now that we can not break user space and SCTP_EMPTY is exposed
 360          * there, we need to fix it up with an ugly offset not to break
 361          * applications. :(
 362          */
 363         return asoc->state + 1;
 364 }
 365
 366 /* Look up the association by its id.  */
 367 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
 368
 369 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
 370
 371 /* A macro to walk a list of skbs.  */
 372 #define sctp_skb_for_each(pos, head, tmp) \
 373         skb_queue_walk_safe(head, pos, tmp)
 374
 375 /**
 376  *      sctp_list_dequeue - remove from the head of the queue
 377  *      @list: list to dequeue from
 378  *
 379  *      Remove the head of the list. The head item is
 380  *      returned or %NULL if the list is empty.
 381  */
 382
 383 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
 384 {
 385         struct list_head *result = NULL;
 386
 387         if (!list_empty(list)) {
 388                 result = list->next;
 389                 list_del_init(result);
 390         }
 391         return result;
 392 }
 393
 394 /* SCTP version of skb_set_owner_r.  We need this one because
 395  * of the way we have to do receive buffer accounting on bundled
 396  * chunks.
 397  */
 398 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
 399 {
 400         struct sctp_ulpevent *event = sctp_skb2event(skb);
 401
 402         skb_orphan(skb);
 403         skb->sk = sk;
 404         skb->destructor = sctp_sock_rfree;
 405         atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
 406         /*
 407          * This mimics the behavior of skb_set_owner_r
 408          */
 409         sk_mem_charge(sk, event->rmem_len);
 410 }
 411
 412 /* Tests if the list has one and only one entry. */
 413 static inline int sctp_list_single_entry(struct list_head *head)
 414 {
 415         return (head->next != head) && (head->next == head->prev);
 416 }
 417
 418 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
 419 {
 420         return !list_empty(&chunk->list);
 421 }
 422
 423 /* Walk through a list of TLV parameters.  Don't trust the
 424  * individual parameter lengths and instead depend on
 425  * the chunk length to indicate when to stop.  Make sure
 426  * there is room for a param header too.
 427  */
 428 #define sctp_walk_params(pos, chunk, member)\
 429 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
 430
 431 #define _sctp_walk_params(pos, chunk, end, member)\
 432 for (pos.v = chunk->member;\
 433      (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <=\
 434       (void *)chunk + end) &&\
 435      pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
 436      ntohs(pos.p->length) >= sizeof(struct sctp_paramhdr);\
 437      pos.v += SCTP_PAD4(ntohs(pos.p->length)))
 438
 439 #define sctp_walk_errors(err, chunk_hdr)\
 440 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
 441
 442 #define _sctp_walk_errors(err, chunk_hdr, end)\
 443 for (err = (struct sctp_errhdr *)((void *)chunk_hdr + \
 444             sizeof(struct sctp_chunkhdr));\
 445      ((void *)err + offsetof(struct sctp_errhdr, length) + sizeof(err->length) <=\
 446       (void *)chunk_hdr + end) &&\
 447      (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
 448      ntohs(err->length) >= sizeof(struct sctp_errhdr); \
 449      err = (struct sctp_errhdr *)((void *)err + SCTP_PAD4(ntohs(err->length))))
 450
 451 #define sctp_walk_fwdtsn(pos, chunk)\
 452 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
 453
 454 #define _sctp_walk_fwdtsn(pos, chunk, end)\
 455 for (pos = chunk->subh.fwdtsn_hdr->skip;\
 456      (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
 457      pos++)
 458
 459 /* External references. */
 460
 461 extern struct proto sctp_prot;
 462 extern struct proto sctpv6_prot;
 463 void sctp_put_port(struct sock *sk);
 464
 465 extern struct idr sctp_assocs_id;
 466 extern spinlock_t sctp_assocs_id_lock;
 467
 468 /* Static inline functions. */
 469
 470 /* Convert from an IP version number to an Address Family symbol.  */
 471 static inline int ipver2af(__u8 ipver)
 472 {
 473         switch (ipver) {
 474         case 4:
 475                 return  AF_INET;
 476         case 6:
 477                 return AF_INET6;
 478         default:
 479                 return 0;
 480         }
 481 }
 482
 483 /* Convert from an address parameter type to an address family.  */
 484 static inline int param_type2af(__be16 type)
 485 {
 486         switch (type) {
 487         case SCTP_PARAM_IPV4_ADDRESS:
 488                 return  AF_INET;
 489         case SCTP_PARAM_IPV6_ADDRESS:
 490                 return AF_INET6;
 491         default:
 492                 return 0;
 493         }
 494 }
 495
 496 /* Warning: The following hash functions assume a power of two 'size'. */
 497 /* This is the hash function for the SCTP port hash table. */
 498 static inline int sctp_phashfn(struct net *net, __u16 lport)
 499 {
 500         return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
 501 }
 502
 503 /* This is the hash function for the endpoint hash table. */
 504 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
 505 {
 506         return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
 507 }
 508
 509 #define sctp_for_each_hentry(epb, head) \
 510         hlist_for_each_entry(epb, head, node)
 511
 512 /* Is a socket of this style? */
 513 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
 514 static inline int __sctp_style(const struct sock *sk,
 515                                enum sctp_socket_type style)
 516 {
 517         return sctp_sk(sk)->type == style;
 518 }
 519
 520 /* Is the association in this state? */
 521 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
 522 static inline int __sctp_state(const struct sctp_association *asoc,
 523                                enum sctp_state state)
 524 {
 525         return asoc->state == state;
 526 }
 527
 528 /* Is the socket in this state? */
 529 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
 530 static inline int __sctp_sstate(const struct sock *sk,
 531                                 enum sctp_sock_state state)
 532 {
 533         return sk->sk_state == state;
 534 }
 535
 536 /* Map v4-mapped v6 address back to v4 address */
 537 static inline void sctp_v6_map_v4(union sctp_addr *addr)
 538 {
 539         addr->v4.sin_family = AF_INET;
 540         addr->v4.sin_port = addr->v6.sin6_port;
 541         addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
 542 }
 543
 544 /* Map v4 address to v4-mapped v6 address */
 545 static inline void sctp_v4_map_v6(union sctp_addr *addr)
 546 {
 547         __be16 port;
 548
 549         port = addr->v4.sin_port;
 550         addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
 551         addr->v6.sin6_port = port;
 552         addr->v6.sin6_family = AF_INET6;
 553         addr->v6.sin6_flowinfo = 0;
 554         addr->v6.sin6_scope_id = 0;
 555         addr->v6.sin6_addr.s6_addr32[0] = 0;
 556         addr->v6.sin6_addr.s6_addr32[1] = 0;
 557         addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
 558 }
 559
 560 /* The cookie is always 0 since this is how it's used in the
 561  * pmtu code.
 562  */
 563 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
 564 {
 565         if (t->dst && !dst_check(t->dst, t->dst_cookie))
 566                 sctp_transport_dst_release(t);
 567
 568         return t->dst;
 569 }
 570
 571 /* Calculate max payload size given a MTU, or the total overhead if
 572  * given MTU is zero
 573  */
 574 static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
 575                                      __u32 mtu, __u32 extra)
 576 {
 577         __u32 overhead = sizeof(struct sctphdr) + extra;
 578
 579         if (sp)
 580                 overhead += sp->pf->af->net_header_len;
 581         else
 582                 overhead += sizeof(struct ipv6hdr);
 583
 584         if (WARN_ON_ONCE(mtu && mtu <= overhead))
 585                 mtu = overhead;
 586
 587         return mtu ? mtu - overhead : overhead;
 588 }
 589
 590 static inline __u32 sctp_dst_mtu(const struct dst_entry *dst)
 591 {
 592         return SCTP_TRUNC4(max_t(__u32, dst_mtu(dst),
 593                                  SCTP_DEFAULT_MINSEGMENT));
 594 }
 595
 596 static inline bool sctp_transport_pmtu_check(struct sctp_transport *t)
 597 {
 598         __u32 pmtu = sctp_dst_mtu(t->dst);
 599
 600         if (t->pathmtu == pmtu)
 601                 return true;
 602
 603         t->pathmtu = pmtu;
 604
 605         return false;
 606 }
 607
 608 static inline __u32 sctp_min_frag_point(struct sctp_sock *sp, __u16 datasize)
 609 {
 610         return sctp_mtu_payload(sp, SCTP_DEFAULT_MINSEGMENT, datasize);
 611 }
 612
 613 #endif /* __net_sctp_h__ */