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__ */ 614