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 /*
71 * Function declarations.
72 */
73
74 /*
75 * sctp/protocol.c
76 */
77 int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *addr,
78 enum sctp_scope, gfp_t gfp, int flags);
79 struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
80 int sctp_register_pf(struct sctp_pf *, sa_family_t);
81 void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
82 int sctp_udp_sock_start(struct net *net);
83 void sctp_udp_sock_stop(struct net *net);
84
85 /*
86 * sctp/socket.c
87 */
88 int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
89 int addr_len, int flags);
90 int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
91 int sctp_inet_listen(struct socket *sock, int backlog);
92 void sctp_write_space(struct sock *sk);
93 void sctp_data_ready(struct sock *sk);
94 __poll_t sctp_poll(struct file *file, struct socket *sock,
95 poll_table *wait);
96 void sctp_sock_rfree(struct sk_buff *skb);
97 void sctp_copy_sock(struct sock *newsk, struct sock *sk,
98 struct sctp_association *asoc);
99 extern struct percpu_counter sctp_sockets_allocated;
100 int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
101 struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int *);
102
103 typedef int (*sctp_callback_t)(struct sctp_endpoint *, struct sctp_transport *, void *);
104 void sctp_transport_walk_start(struct rhashtable_iter *iter);
105 void sctp_transport_walk_stop(struct rhashtable_iter *iter);
106 struct sctp_transport *sctp_transport_get_next(struct net *net,
107 struct rhashtable_iter *iter);
108 struct sctp_transport *sctp_transport_get_idx(struct net *net,
109 struct rhashtable_iter *iter, int pos);
110 int sctp_transport_lookup_process(sctp_callback_t cb, struct net *net,
111 const union sctp_addr *laddr,
112 const union sctp_addr *paddr, void *p, int dif);
113 int sctp_transport_traverse_process(sctp_callback_t cb, sctp_callback_t cb_done,
114 struct net *net, int *pos, void *p);
115 int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p);
116 int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
117 struct sctp_info *info);
118
119 /*
120 * sctp/primitive.c
121 */
122 int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
123 int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
124 int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
125 int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
126 int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
127 int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
128 int sctp_primitive_RECONF(struct net *net, struct sctp_association *asoc,
129 void *arg);
130
131 /*
132 * sctp/input.c
133 */
134 int sctp_rcv(struct sk_buff *skb);
135 int sctp_v4_err(struct sk_buff *skb, u32 info);
136 int sctp_hash_endpoint(struct sctp_endpoint *ep);
137 void sctp_unhash_endpoint(struct sctp_endpoint *);
138 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
139 struct sctphdr *, struct sctp_association **,
140 struct sctp_transport **);
141 void sctp_err_finish(struct sock *, struct sctp_transport *);
142 int sctp_udp_v4_err(struct sock *sk, struct sk_buff *skb);
143 int sctp_udp_v6_err(struct sock *sk, struct sk_buff *skb);
144 void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
145 struct sctp_transport *t, __u32 pmtu);
146 void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
147 struct sk_buff *);
148 void sctp_icmp_proto_unreachable(struct sock *sk,
149 struct sctp_association *asoc,
150 struct sctp_transport *t);
151 int sctp_transport_hashtable_init(void);
152 void sctp_transport_hashtable_destroy(void);
153 int sctp_hash_transport(struct sctp_transport *t);
154 void sctp_unhash_transport(struct sctp_transport *t);
155 struct sctp_transport *sctp_addrs_lookup_transport(
156 struct net *net,
157 const union sctp_addr *laddr,
158 const union sctp_addr *paddr,
159 int dif, int sdif);
160 struct sctp_transport *sctp_epaddr_lookup_transport(
161 const struct sctp_endpoint *ep,
162 const union sctp_addr *paddr);
163 bool sctp_sk_bound_dev_eq(struct net *net, int bound_dev_if, int dif, int sdif);
164
165 /*
166 * sctp/proc.c
167 */
168 int __net_init sctp_proc_init(struct net *net);
169
170 /*
171 * sctp/offload.c
172 */
173 int sctp_offload_init(void);
174
175 /*
176 * sctp/stream_sched.c
177 */
178 void sctp_sched_ops_init(void);
179
180 /*
181 * sctp/stream.c
182 */
183 int sctp_send_reset_streams(struct sctp_association *asoc,
184 struct sctp_reset_streams *params);
185 int sctp_send_reset_assoc(struct sctp_association *asoc);
186 int sctp_send_add_streams(struct sctp_association *asoc,
187 struct sctp_add_streams *params);
188
189 /*
190 * Module global variables
191 */
192
193 /*
194 * sctp/protocol.c
195 */
196 extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
197 extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
198 extern long sysctl_sctp_mem[3];
199 extern int sysctl_sctp_rmem[3];
200 extern int sysctl_sctp_wmem[3];
201
202 /*
203 * Section: Macros, externs, and inlines
204 */
205
206 /* SCTP SNMP MIB stats handlers */
207 #define SCTP_INC_STATS(net, field) SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
208 #define __SCTP_INC_STATS(net, field) __SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
209 #define SCTP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
210
211 /* sctp mib definitions */
212 enum {
213 SCTP_MIB_NUM = 0,
214 SCTP_MIB_CURRESTAB, /* CurrEstab */
215 SCTP_MIB_ACTIVEESTABS, /* ActiveEstabs */
216 SCTP_MIB_PASSIVEESTABS, /* PassiveEstabs */
217 SCTP_MIB_ABORTEDS, /* Aborteds */
218 SCTP_MIB_SHUTDOWNS, /* Shutdowns */
219 SCTP_MIB_OUTOFBLUES, /* OutOfBlues */
220 SCTP_MIB_CHECKSUMERRORS, /* ChecksumErrors */
221 SCTP_MIB_OUTCTRLCHUNKS, /* OutCtrlChunks */
222 SCTP_MIB_OUTORDERCHUNKS, /* OutOrderChunks */
223 SCTP_MIB_OUTUNORDERCHUNKS, /* OutUnorderChunks */
224 SCTP_MIB_INCTRLCHUNKS, /* InCtrlChunks */
225 SCTP_MIB_INORDERCHUNKS, /* InOrderChunks */
226 SCTP_MIB_INUNORDERCHUNKS, /* InUnorderChunks */
227 SCTP_MIB_FRAGUSRMSGS, /* FragUsrMsgs */
228 SCTP_MIB_REASMUSRMSGS, /* ReasmUsrMsgs */
229 SCTP_MIB_OUTSCTPPACKS, /* OutSCTPPacks */
230 SCTP_MIB_INSCTPPACKS, /* InSCTPPacks */
231 SCTP_MIB_T1_INIT_EXPIREDS,
232 SCTP_MIB_T1_COOKIE_EXPIREDS,
233 SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
234 SCTP_MIB_T3_RTX_EXPIREDS,
235 SCTP_MIB_T4_RTO_EXPIREDS,
236 SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
237 SCTP_MIB_DELAY_SACK_EXPIREDS,
238 SCTP_MIB_AUTOCLOSE_EXPIREDS,
239 SCTP_MIB_T1_RETRANSMITS,
240 SCTP_MIB_T3_RETRANSMITS,
241 SCTP_MIB_PMTUD_RETRANSMITS,
242 SCTP_MIB_FAST_RETRANSMITS,
243 SCTP_MIB_IN_PKT_SOFTIRQ,
244 SCTP_MIB_IN_PKT_BACKLOG,
245 SCTP_MIB_IN_PKT_DISCARDS,
246 SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
247 __SCTP_MIB_MAX
248 };
249
250 #define SCTP_MIB_MAX __SCTP_MIB_MAX
251 struct sctp_mib {
252 unsigned long mibs[SCTP_MIB_MAX];
253 };
254
255 /* helper function to track stats about max rto and related transport */
256 static inline void sctp_max_rto(struct sctp_association *asoc,
257 struct sctp_transport *trans)
258 {
259 if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
260 asoc->stats.max_obs_rto = trans->rto;
261 memset(&asoc->stats.obs_rto_ipaddr, 0,
262 sizeof(struct sockaddr_storage));
263 memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
264 trans->af_specific->sockaddr_len);
265 }
266 }
267
268 /*
269 * Macros for keeping a global reference of object allocations.
270 */
271 #ifdef CONFIG_SCTP_DBG_OBJCNT
272
273 extern atomic_t sctp_dbg_objcnt_sock;
274 extern atomic_t sctp_dbg_objcnt_ep;
275 extern atomic_t sctp_dbg_objcnt_assoc;
276 extern atomic_t sctp_dbg_objcnt_transport;
277 extern atomic_t sctp_dbg_objcnt_chunk;
278 extern atomic_t sctp_dbg_objcnt_bind_addr;
279 extern atomic_t sctp_dbg_objcnt_bind_bucket;
280 extern atomic_t sctp_dbg_objcnt_addr;
281 extern atomic_t sctp_dbg_objcnt_datamsg;
282 extern atomic_t sctp_dbg_objcnt_keys;
283
284 /* Macros to atomically increment/decrement objcnt counters. */
285 #define SCTP_DBG_OBJCNT_INC(name) \
286 atomic_inc(&sctp_dbg_objcnt_## name)
287 #define SCTP_DBG_OBJCNT_DEC(name) \
288 atomic_dec(&sctp_dbg_objcnt_## name)
289 #define SCTP_DBG_OBJCNT(name) \
290 atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
291
292 /* Macro to help create new entries in the global array of
293 * objcnt counters.
294 */
295 #define SCTP_DBG_OBJCNT_ENTRY(name) \
296 {.label= #name, .counter= &sctp_dbg_objcnt_## name}
297
298 void sctp_dbg_objcnt_init(struct net *);
299
300 #else
301
302 #define SCTP_DBG_OBJCNT_INC(name)
303 #define SCTP_DBG_OBJCNT_DEC(name)
304
305 static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
306
307 #endif /* CONFIG_SCTP_DBG_OBJCOUNT */
308
309 #if defined CONFIG_SYSCTL
310 void sctp_sysctl_register(void);
311 void sctp_sysctl_unregister(void);
312 int sctp_sysctl_net_register(struct net *net);
313 void sctp_sysctl_net_unregister(struct net *net);
314 #else
315 static inline void sctp_sysctl_register(void) { return; }
316 static inline void sctp_sysctl_unregister(void) { return; }
317 static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
318 static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
319 #endif
320
321 /* Size of Supported Address Parameter for 'x' address types. */
322 #define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
323
324 #if IS_ENABLED(CONFIG_IPV6)
325
326 void sctp_v6_pf_init(void);
327 void sctp_v6_pf_exit(void);
328 int sctp_v6_protosw_init(void);
329 void sctp_v6_protosw_exit(void);
330 int sctp_v6_add_protocol(void);
331 void sctp_v6_del_protocol(void);
332
333 #else /* #ifdef defined(CONFIG_IPV6) */
334
335 static inline void sctp_v6_pf_init(void) { return; }
336 static inline void sctp_v6_pf_exit(void) { return; }
337 static inline int sctp_v6_protosw_init(void) { return 0; }
338 static inline void sctp_v6_protosw_exit(void) { return; }
339 static inline int sctp_v6_add_protocol(void) { return 0; }
340 static inline void sctp_v6_del_protocol(void) { return; }
341
342 #endif /* #if defined(CONFIG_IPV6) */
343
344
345 /* Map an association to an assoc_id. */
346 static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
347 {
348 return asoc ? asoc->assoc_id : 0;
349 }
350
351 static inline enum sctp_sstat_state
352 sctp_assoc_to_state(const struct sctp_association *asoc)
353 {
354 /* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
355 * got rid of it in kernel space. Therefore SCTP_CLOSED et al
356 * start at =1 in user space, but actually as =0 in kernel space.
357 * Now that we can not break user space and SCTP_EMPTY is exposed
358 * there, we need to fix it up with an ugly offset not to break
359 * applications. :(
360 */
361 return asoc->state + 1;
362 }
363
364 /* Look up the association by its id. */
365 struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
366
367 int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
368
369 /* A macro to walk a list of skbs. */
370 #define sctp_skb_for_each(pos, head, tmp) \
371 skb_queue_walk_safe(head, pos, tmp)
372
373 /**
374 * sctp_list_dequeue - remove from the head of the queue
375 * @list: list to dequeue from
376 *
377 * Remove the head of the list. The head item is
378 * returned or %NULL if the list is empty.
379 */
380
381 static inline struct list_head *sctp_list_dequeue(struct list_head *list)
382 {
383 struct list_head *result = NULL;
384
385 if (!list_empty(list)) {
386 result = list->next;
387 list_del_init(result);
388 }
389 return result;
390 }
391
392 /* SCTP version of skb_set_owner_r. We need this one because
393 * of the way we have to do receive buffer accounting on bundled
394 * chunks.
395 */
396 static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
397 {
398 struct sctp_ulpevent *event = sctp_skb2event(skb);
399
400 skb_orphan(skb);
401 skb->sk = sk;
402 skb->destructor = sctp_sock_rfree;
403 atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
404 /*
405 * This mimics the behavior of skb_set_owner_r
406 */
407 sk_mem_charge(sk, event->rmem_len);
408 }
409
410 /* Tests if the list has one and only one entry. */
411 static inline int sctp_list_single_entry(struct list_head *head)
412 {
413 return list_is_singular(head);
414 }
415
416 static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
417 {
418 return !list_empty(&chunk->list);
419 }
420
421 /* Walk through a list of TLV parameters. Don't trust the
422 * individual parameter lengths and instead depend on
423 * the chunk length to indicate when to stop. Make sure
424 * there is room for a param header too.
425 */
426 #define sctp_walk_params(pos, chunk)\
427 _sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length))
428
429 #define _sctp_walk_params(pos, chunk, end)\
430 for (pos.v = (u8 *)(chunk + 1);\
431 (pos.v + offsetof(struct sctp_paramhdr, length) + sizeof(pos.p->length) <=\
432 (void *)chunk + end) &&\
433 pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
434 ntohs(pos.p->length) >= sizeof(struct sctp_paramhdr);\
435 pos.v += SCTP_PAD4(ntohs(pos.p->length)))
436
437 #define sctp_walk_errors(err, chunk_hdr)\
438 _sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
439
440 #define _sctp_walk_errors(err, chunk_hdr, end)\
441 for (err = (struct sctp_errhdr *)((void *)chunk_hdr + \
442 sizeof(struct sctp_chunkhdr));\
443 ((void *)err + offsetof(struct sctp_errhdr, length) + sizeof(err->length) <=\
444 (void *)chunk_hdr + end) &&\
445 (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
446 ntohs(err->length) >= sizeof(struct sctp_errhdr); \
447 err = (struct sctp_errhdr *)((void *)err + SCTP_PAD4(ntohs(err->length))))
448
449 #define sctp_walk_fwdtsn(pos, chunk)\
450 _sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
451
452 #define _sctp_walk_fwdtsn(pos, chunk, end)\
453 for (pos = (void *)(chunk->subh.fwdtsn_hdr + 1);\
454 (void *)pos <= (void *)(chunk->subh.fwdtsn_hdr + 1) + end - sizeof(struct sctp_fwdtsn_skip);\
455 pos++)
456
457 /* External references. */
458
459 extern struct proto sctp_prot;
460 extern struct proto sctpv6_prot;
461 void sctp_put_port(struct sock *sk);
462
463 extern struct idr sctp_assocs_id;
464 extern spinlock_t sctp_assocs_id_lock;
465
466 /* Static inline functions. */
467
468 /* Convert from an IP version number to an Address Family symbol. */
469 static inline int ipver2af(__u8 ipver)
470 {
471 switch (ipver) {
472 case 4:
473 return AF_INET;
474 case 6:
475 return AF_INET6;
476 default:
477 return 0;
478 }
479 }
480
481 /* Convert from an address parameter type to an address family. */
482 static inline int param_type2af(__be16 type)
483 {
484 switch (type) {
485 case SCTP_PARAM_IPV4_ADDRESS:
486 return AF_INET;
487 case SCTP_PARAM_IPV6_ADDRESS:
488 return AF_INET6;
489 default:
490 return 0;
491 }
492 }
493
494 /* Warning: The following hash functions assume a power of two 'size'. */
495 /* This is the hash function for the SCTP port hash table. */
496 static inline int sctp_phashfn(struct net *net, __u16 lport)
497 {
498 return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
499 }
500
501 /* This is the hash function for the endpoint hash table. */
502 static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
503 {
504 return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
505 }
506
507 #define sctp_for_each_hentry(ep, head) \
508 hlist_for_each_entry(ep, head, node)
509
510 /* Is a socket of this style? */
511 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
512 static inline int __sctp_style(const struct sock *sk,
513 enum sctp_socket_type style)
514 {
515 return sctp_sk(sk)->type == style;
516 }
517
518 /* Is the association in this state? */
519 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
520 static inline int __sctp_state(const struct sctp_association *asoc,
521 enum sctp_state state)
522 {
523 return asoc->state == state;
524 }
525
526 /* Is the socket in this state? */
527 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
528 static inline int __sctp_sstate(const struct sock *sk,
529 enum sctp_sock_state state)
530 {
531 return sk->sk_state == state;
532 }
533
534 /* Map v4-mapped v6 address back to v4 address */
535 static inline void sctp_v6_map_v4(union sctp_addr *addr)
536 {
537 addr->v4.sin_family = AF_INET;
538 addr->v4.sin_port = addr->v6.sin6_port;
539 addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
540 }
541
542 /* Map v4 address to v4-mapped v6 address */
543 static inline void sctp_v4_map_v6(union sctp_addr *addr)
544 {
545 __be16 port;
546
547 port = addr->v4.sin_port;
548 addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
549 addr->v6.sin6_port = port;
550 addr->v6.sin6_family = AF_INET6;
551 addr->v6.sin6_flowinfo = 0;
552 addr->v6.sin6_scope_id = 0;
553 addr->v6.sin6_addr.s6_addr32[0] = 0;
554 addr->v6.sin6_addr.s6_addr32[1] = 0;
555 addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
556 }
557
558 /* The cookie is always 0 since this is how it's used in the
559 * pmtu code.
560 */
561 static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
562 {
563 if (t->dst && !dst_check(t->dst, t->dst_cookie))
564 sctp_transport_dst_release(t);
565
566 return t->dst;
567 }
568
569 /* Calculate max payload size given a MTU, or the total overhead if
570 * given MTU is zero
571 */
572 static inline __u32 __sctp_mtu_payload(const struct sctp_sock *sp,
573 const struct sctp_transport *t,
574 __u32 mtu, __u32 extra)
575 {
576 __u32 overhead = sizeof(struct sctphdr) + extra;
577
578 if (sp) {
579 overhead += sp->pf->af->net_header_len;
580 if (sp->udp_port && (!t || t->encap_port))
581 overhead += sizeof(struct udphdr);
582 } else {
583 overhead += sizeof(struct ipv6hdr);
584 }
585
586 if (WARN_ON_ONCE(mtu && mtu <= overhead))
587 mtu = overhead;
588
589 return mtu ? mtu - overhead : overhead;
590 }
591
592 static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
593 __u32 mtu, __u32 extra)
594 {
595 return __sctp_mtu_payload(sp, NULL, mtu, extra);
596 }
597
598 static inline __u32 sctp_dst_mtu(const struct dst_entry *dst)
599 {
600 return SCTP_TRUNC4(max_t(__u32, dst_mtu(dst),
601 SCTP_DEFAULT_MINSEGMENT));
602 }
603
604 static inline bool sctp_transport_pmtu_check(struct sctp_transport *t)
605 {
606 __u32 pmtu = sctp_dst_mtu(t->dst);
607
608 if (t->pathmtu == pmtu)
609 return true;
610
611 t->pathmtu = pmtu;
612
613 return false;
614 }
615
616 static inline __u32 sctp_min_frag_point(struct sctp_sock *sp, __u16 datasize)
617 {
618 return sctp_mtu_payload(sp, SCTP_DEFAULT_MINSEGMENT, datasize);
619 }
620
621 static inline int sctp_transport_pl_hlen(struct sctp_transport *t)
622 {
623 return __sctp_mtu_payload(sctp_sk(t->asoc->base.sk), t, 0, 0) -
624 sizeof(struct sctphdr);
625 }
626
627 static inline void sctp_transport_pl_reset(struct sctp_transport *t)
628 {
629 if (t->probe_interval && (t->param_flags & SPP_PMTUD_ENABLE) &&
630 (t->state == SCTP_ACTIVE || t->state == SCTP_UNKNOWN)) {
631 if (t->pl.state == SCTP_PL_DISABLED) {
632 t->pl.state = SCTP_PL_BASE;
633 t->pl.pmtu = SCTP_BASE_PLPMTU;
634 t->pl.probe_size = SCTP_BASE_PLPMTU;
635 sctp_transport_reset_probe_timer(t);
636 }
637 } else {
638 if (t->pl.state != SCTP_PL_DISABLED) {
639 if (del_timer(&t->probe_timer))
640 sctp_transport_put(t);
641 t->pl.state = SCTP_PL_DISABLED;
642 }
643 }
644 }
645
646 static inline void sctp_transport_pl_update(struct sctp_transport *t)
647 {
648 if (t->pl.state == SCTP_PL_DISABLED)
649 return;
650
651 t->pl.state = SCTP_PL_BASE;
652 t->pl.pmtu = SCTP_BASE_PLPMTU;
653 t->pl.probe_size = SCTP_BASE_PLPMTU;
654 sctp_transport_reset_probe_timer(t);
655 }
656
657 static inline bool sctp_transport_pl_enabled(struct sctp_transport *t)
658 {
659 return t->pl.state != SCTP_PL_DISABLED;
660 }
661
662 static inline bool sctp_newsk_ready(const struct sock *sk)
663 {
664 return sock_flag(sk, SOCK_DEAD) || sk->sk_socket;
665 }
666
667 static inline void sctp_sock_set_nodelay(struct sock *sk)
668 {
669 lock_sock(sk);
670 sctp_sk(sk)->nodelay = true;
671 release_sock(sk);
672 }
673
674 #endif /* __net_sctp_h__ */
675
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