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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) 2001-2003 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 <asm/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 WORD_ROUND(s) (((s)+3)&~3)
87/* Truncate to the previous multiple of 4. */
88#define WORD_TRUNC(s) ((s)&~3)
89
90/*
91 * Function declarations.
92 */
93
94/*
95 * sctp/protocol.c
96 */
97int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
98 sctp_scope_t, gfp_t gfp, int flags);
99struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
100int sctp_register_pf(struct sctp_pf *, sa_family_t);
101void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
102
103/*
104 * sctp/socket.c
105 */
106int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
107int sctp_inet_listen(struct socket *sock, int backlog);
108void sctp_write_space(struct sock *sk);
109void sctp_data_ready(struct sock *sk);
110unsigned int sctp_poll(struct file *file, struct socket *sock,
111 poll_table *wait);
112void sctp_sock_rfree(struct sk_buff *skb);
113void sctp_copy_sock(struct sock *newsk, struct sock *sk,
114 struct sctp_association *asoc);
115extern struct percpu_counter sctp_sockets_allocated;
116int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
117struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int, int *);
118
119/*
120 * sctp/primitive.c
121 */
122int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
123int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
124int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
125int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
126int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
127int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
128
129/*
130 * sctp/input.c
131 */
132int sctp_rcv(struct sk_buff *skb);
133void sctp_v4_err(struct sk_buff *skb, u32 info);
134void sctp_hash_endpoint(struct sctp_endpoint *);
135void sctp_unhash_endpoint(struct sctp_endpoint *);
136struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
137 struct sctphdr *, struct sctp_association **,
138 struct sctp_transport **);
139void sctp_err_finish(struct sock *, struct sctp_association *);
140void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
141 struct sctp_transport *t, __u32 pmtu);
142void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
143 struct sk_buff *);
144void sctp_icmp_proto_unreachable(struct sock *sk,
145 struct sctp_association *asoc,
146 struct sctp_transport *t);
147void sctp_backlog_migrate(struct sctp_association *assoc,
148 struct sock *oldsk, struct sock *newsk);
149int sctp_transport_hashtable_init(void);
150void sctp_transport_hashtable_destroy(void);
151void sctp_hash_transport(struct sctp_transport *t);
152void sctp_unhash_transport(struct sctp_transport *t);
153struct sctp_transport *sctp_addrs_lookup_transport(
154 struct net *net,
155 const union sctp_addr *laddr,
156 const union sctp_addr *paddr);
157struct sctp_transport *sctp_epaddr_lookup_transport(
158 const struct sctp_endpoint *ep,
159 const union sctp_addr *paddr);
160
161/*
162 * sctp/proc.c
163 */
164int sctp_snmp_proc_init(struct net *net);
165void sctp_snmp_proc_exit(struct net *net);
166int sctp_eps_proc_init(struct net *net);
167void sctp_eps_proc_exit(struct net *net);
168int sctp_assocs_proc_init(struct net *net);
169void sctp_assocs_proc_exit(struct net *net);
170int sctp_remaddr_proc_init(struct net *net);
171void sctp_remaddr_proc_exit(struct net *net);
172
173
174/*
175 * Module global variables
176 */
177
178 /*
179 * sctp/protocol.c
180 */
181extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
182extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
183extern long sysctl_sctp_mem[3];
184extern int sysctl_sctp_rmem[3];
185extern int sysctl_sctp_wmem[3];
186
187/*
188 * Section: Macros, externs, and inlines
189 */
190
191/* SCTP SNMP MIB stats handlers */
192#define SCTP_INC_STATS(net, field) SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
193#define SCTP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
194#define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
195#define SCTP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
196
197/* sctp mib definitions */
198enum {
199 SCTP_MIB_NUM = 0,
200 SCTP_MIB_CURRESTAB, /* CurrEstab */
201 SCTP_MIB_ACTIVEESTABS, /* ActiveEstabs */
202 SCTP_MIB_PASSIVEESTABS, /* PassiveEstabs */
203 SCTP_MIB_ABORTEDS, /* Aborteds */
204 SCTP_MIB_SHUTDOWNS, /* Shutdowns */
205 SCTP_MIB_OUTOFBLUES, /* OutOfBlues */
206 SCTP_MIB_CHECKSUMERRORS, /* ChecksumErrors */
207 SCTP_MIB_OUTCTRLCHUNKS, /* OutCtrlChunks */
208 SCTP_MIB_OUTORDERCHUNKS, /* OutOrderChunks */
209 SCTP_MIB_OUTUNORDERCHUNKS, /* OutUnorderChunks */
210 SCTP_MIB_INCTRLCHUNKS, /* InCtrlChunks */
211 SCTP_MIB_INORDERCHUNKS, /* InOrderChunks */
212 SCTP_MIB_INUNORDERCHUNKS, /* InUnorderChunks */
213 SCTP_MIB_FRAGUSRMSGS, /* FragUsrMsgs */
214 SCTP_MIB_REASMUSRMSGS, /* ReasmUsrMsgs */
215 SCTP_MIB_OUTSCTPPACKS, /* OutSCTPPacks */
216 SCTP_MIB_INSCTPPACKS, /* InSCTPPacks */
217 SCTP_MIB_T1_INIT_EXPIREDS,
218 SCTP_MIB_T1_COOKIE_EXPIREDS,
219 SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
220 SCTP_MIB_T3_RTX_EXPIREDS,
221 SCTP_MIB_T4_RTO_EXPIREDS,
222 SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
223 SCTP_MIB_DELAY_SACK_EXPIREDS,
224 SCTP_MIB_AUTOCLOSE_EXPIREDS,
225 SCTP_MIB_T1_RETRANSMITS,
226 SCTP_MIB_T3_RETRANSMITS,
227 SCTP_MIB_PMTUD_RETRANSMITS,
228 SCTP_MIB_FAST_RETRANSMITS,
229 SCTP_MIB_IN_PKT_SOFTIRQ,
230 SCTP_MIB_IN_PKT_BACKLOG,
231 SCTP_MIB_IN_PKT_DISCARDS,
232 SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
233 __SCTP_MIB_MAX
234};
235
236#define SCTP_MIB_MAX __SCTP_MIB_MAX
237struct sctp_mib {
238 unsigned long mibs[SCTP_MIB_MAX];
239};
240
241/* helper function to track stats about max rto and related transport */
242static inline void sctp_max_rto(struct sctp_association *asoc,
243 struct sctp_transport *trans)
244{
245 if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
246 asoc->stats.max_obs_rto = trans->rto;
247 memset(&asoc->stats.obs_rto_ipaddr, 0,
248 sizeof(struct sockaddr_storage));
249 memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
250 trans->af_specific->sockaddr_len);
251 }
252}
253
254/*
255 * Macros for keeping a global reference of object allocations.
256 */
257#ifdef CONFIG_SCTP_DBG_OBJCNT
258
259extern atomic_t sctp_dbg_objcnt_sock;
260extern atomic_t sctp_dbg_objcnt_ep;
261extern atomic_t sctp_dbg_objcnt_assoc;
262extern atomic_t sctp_dbg_objcnt_transport;
263extern atomic_t sctp_dbg_objcnt_chunk;
264extern atomic_t sctp_dbg_objcnt_bind_addr;
265extern atomic_t sctp_dbg_objcnt_bind_bucket;
266extern atomic_t sctp_dbg_objcnt_addr;
267extern atomic_t sctp_dbg_objcnt_ssnmap;
268extern atomic_t sctp_dbg_objcnt_datamsg;
269extern atomic_t sctp_dbg_objcnt_keys;
270
271/* Macros to atomically increment/decrement objcnt counters. */
272#define SCTP_DBG_OBJCNT_INC(name) \
273atomic_inc(&sctp_dbg_objcnt_## name)
274#define SCTP_DBG_OBJCNT_DEC(name) \
275atomic_dec(&sctp_dbg_objcnt_## name)
276#define SCTP_DBG_OBJCNT(name) \
277atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
278
279/* Macro to help create new entries in in the global array of
280 * objcnt counters.
281 */
282#define SCTP_DBG_OBJCNT_ENTRY(name) \
283{.label= #name, .counter= &sctp_dbg_objcnt_## name}
284
285void sctp_dbg_objcnt_init(struct net *);
286void sctp_dbg_objcnt_exit(struct net *);
287
288#else
289
290#define SCTP_DBG_OBJCNT_INC(name)
291#define SCTP_DBG_OBJCNT_DEC(name)
292
293static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
294static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
295
296#endif /* CONFIG_SCTP_DBG_OBJCOUNT */
297
298#if defined CONFIG_SYSCTL
299void sctp_sysctl_register(void);
300void sctp_sysctl_unregister(void);
301int sctp_sysctl_net_register(struct net *net);
302void sctp_sysctl_net_unregister(struct net *net);
303#else
304static inline void sctp_sysctl_register(void) { return; }
305static inline void sctp_sysctl_unregister(void) { return; }
306static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
307static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
308#endif
309
310/* Size of Supported Address Parameter for 'x' address types. */
311#define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
312
313#if IS_ENABLED(CONFIG_IPV6)
314
315void sctp_v6_pf_init(void);
316void sctp_v6_pf_exit(void);
317int sctp_v6_protosw_init(void);
318void sctp_v6_protosw_exit(void);
319int sctp_v6_add_protocol(void);
320void sctp_v6_del_protocol(void);
321
322#else /* #ifdef defined(CONFIG_IPV6) */
323
324static inline void sctp_v6_pf_init(void) { return; }
325static inline void sctp_v6_pf_exit(void) { return; }
326static inline int sctp_v6_protosw_init(void) { return 0; }
327static inline void sctp_v6_protosw_exit(void) { return; }
328static inline int sctp_v6_add_protocol(void) { return 0; }
329static inline void sctp_v6_del_protocol(void) { return; }
330
331#endif /* #if defined(CONFIG_IPV6) */
332
333
334/* Map an association to an assoc_id. */
335static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
336{
337 return asoc ? asoc->assoc_id : 0;
338}
339
340static inline enum sctp_sstat_state
341sctp_assoc_to_state(const struct sctp_association *asoc)
342{
343 /* SCTP's uapi always had SCTP_EMPTY(=0) as a dummy state, but we
344 * got rid of it in kernel space. Therefore SCTP_CLOSED et al
345 * start at =1 in user space, but actually as =0 in kernel space.
346 * Now that we can not break user space and SCTP_EMPTY is exposed
347 * there, we need to fix it up with an ugly offset not to break
348 * applications. :(
349 */
350 return asoc->state + 1;
351}
352
353/* Look up the association by its id. */
354struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
355
356int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
357
358/* A macro to walk a list of skbs. */
359#define sctp_skb_for_each(pos, head, tmp) \
360 skb_queue_walk_safe(head, pos, tmp)
361
362/* A helper to append an entire skb list (list) to another (head). */
363static inline void sctp_skb_list_tail(struct sk_buff_head *list,
364 struct sk_buff_head *head)
365{
366 unsigned long flags;
367
368 spin_lock_irqsave(&head->lock, flags);
369 spin_lock(&list->lock);
370
371 skb_queue_splice_tail_init(list, head);
372
373 spin_unlock(&list->lock);
374 spin_unlock_irqrestore(&head->lock, flags);
375}
376
377/**
378 * sctp_list_dequeue - remove from the head of the queue
379 * @list: list to dequeue from
380 *
381 * Remove the head of the list. The head item is
382 * returned or %NULL if the list is empty.
383 */
384
385static inline struct list_head *sctp_list_dequeue(struct list_head *list)
386{
387 struct list_head *result = NULL;
388
389 if (!list_empty(list)) {
390 result = list->next;
391 list_del_init(result);
392 }
393 return result;
394}
395
396/* SCTP version of skb_set_owner_r. We need this one because
397 * of the way we have to do receive buffer accounting on bundled
398 * chunks.
399 */
400static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
401{
402 struct sctp_ulpevent *event = sctp_skb2event(skb);
403
404 skb_orphan(skb);
405 skb->sk = sk;
406 skb->destructor = sctp_sock_rfree;
407 atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
408 /*
409 * This mimics the behavior of skb_set_owner_r
410 */
411 sk->sk_forward_alloc -= event->rmem_len;
412}
413
414/* Tests if the list has one and only one entry. */
415static inline int sctp_list_single_entry(struct list_head *head)
416{
417 return (head->next != head) && (head->next == head->prev);
418}
419
420/* Break down data chunks at this point. */
421static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
422{
423 struct sctp_sock *sp = sctp_sk(asoc->base.sk);
424 int frag = pmtu;
425
426 frag -= sp->pf->af->net_header_len;
427 frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
428
429 if (asoc->user_frag)
430 frag = min_t(int, frag, asoc->user_frag);
431
432 frag = WORD_TRUNC(min_t(int, frag, SCTP_MAX_CHUNK_LEN));
433
434 return frag;
435}
436
437static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
438{
439
440 sctp_assoc_sync_pmtu(sk, asoc);
441 asoc->pmtu_pending = 0;
442}
443
444static inline bool sctp_chunk_pending(const struct sctp_chunk *chunk)
445{
446 return !list_empty(&chunk->list);
447}
448
449/* Walk through a list of TLV parameters. Don't trust the
450 * individual parameter lengths and instead depend on
451 * the chunk length to indicate when to stop. Make sure
452 * there is room for a param header too.
453 */
454#define sctp_walk_params(pos, chunk, member)\
455_sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
456
457#define _sctp_walk_params(pos, chunk, end, member)\
458for (pos.v = chunk->member;\
459 pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
460 ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
461 pos.v += WORD_ROUND(ntohs(pos.p->length)))
462
463#define sctp_walk_errors(err, chunk_hdr)\
464_sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
465
466#define _sctp_walk_errors(err, chunk_hdr, end)\
467for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
468 sizeof(sctp_chunkhdr_t));\
469 (void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
470 ntohs(err->length) >= sizeof(sctp_errhdr_t); \
471 err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
472
473#define sctp_walk_fwdtsn(pos, chunk)\
474_sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
475
476#define _sctp_walk_fwdtsn(pos, chunk, end)\
477for (pos = chunk->subh.fwdtsn_hdr->skip;\
478 (void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
479 pos++)
480
481/* External references. */
482
483extern struct proto sctp_prot;
484extern struct proto sctpv6_prot;
485void sctp_put_port(struct sock *sk);
486
487extern struct idr sctp_assocs_id;
488extern spinlock_t sctp_assocs_id_lock;
489
490/* Static inline functions. */
491
492/* Convert from an IP version number to an Address Family symbol. */
493static inline int ipver2af(__u8 ipver)
494{
495 switch (ipver) {
496 case 4:
497 return AF_INET;
498 case 6:
499 return AF_INET6;
500 default:
501 return 0;
502 }
503}
504
505/* Convert from an address parameter type to an address family. */
506static inline int param_type2af(__be16 type)
507{
508 switch (type) {
509 case SCTP_PARAM_IPV4_ADDRESS:
510 return AF_INET;
511 case SCTP_PARAM_IPV6_ADDRESS:
512 return AF_INET6;
513 default:
514 return 0;
515 }
516}
517
518/* Warning: The following hash functions assume a power of two 'size'. */
519/* This is the hash function for the SCTP port hash table. */
520static inline int sctp_phashfn(struct net *net, __u16 lport)
521{
522 return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
523}
524
525/* This is the hash function for the endpoint hash table. */
526static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
527{
528 return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
529}
530
531#define sctp_for_each_hentry(epb, head) \
532 hlist_for_each_entry(epb, head, node)
533
534/* Is a socket of this style? */
535#define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
536static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
537{
538 return sctp_sk(sk)->type == style;
539}
540
541/* Is the association in this state? */
542#define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
543static inline int __sctp_state(const struct sctp_association *asoc,
544 sctp_state_t state)
545{
546 return asoc->state == state;
547}
548
549/* Is the socket in this state? */
550#define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
551static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
552{
553 return sk->sk_state == state;
554}
555
556/* Map v4-mapped v6 address back to v4 address */
557static inline void sctp_v6_map_v4(union sctp_addr *addr)
558{
559 addr->v4.sin_family = AF_INET;
560 addr->v4.sin_port = addr->v6.sin6_port;
561 addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
562}
563
564/* Map v4 address to v4-mapped v6 address */
565static inline void sctp_v4_map_v6(union sctp_addr *addr)
566{
567 __be16 port;
568
569 port = addr->v4.sin_port;
570 addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
571 addr->v6.sin6_port = port;
572 addr->v6.sin6_family = AF_INET6;
573 addr->v6.sin6_flowinfo = 0;
574 addr->v6.sin6_scope_id = 0;
575 addr->v6.sin6_addr.s6_addr32[0] = 0;
576 addr->v6.sin6_addr.s6_addr32[1] = 0;
577 addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
578}
579
580/* The cookie is always 0 since this is how it's used in the
581 * pmtu code.
582 */
583static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
584{
585 if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
586 dst_release(t->dst);
587 t->dst = NULL;
588 }
589
590 return t->dst;
591}
592
593#endif /* __net_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/*
71 * Function declarations.
72 */
73
74/*
75 * sctp/protocol.c
76 */
77int sctp_copy_local_addr_list(struct net *net, struct sctp_bind_addr *addr,
78 enum sctp_scope, gfp_t gfp, int flags);
79struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
80int sctp_register_pf(struct sctp_pf *, sa_family_t);
81void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
82int sctp_udp_sock_start(struct net *net);
83void sctp_udp_sock_stop(struct net *net);
84
85/*
86 * sctp/socket.c
87 */
88int sctp_inet_connect(struct socket *sock, struct sockaddr *uaddr,
89 int addr_len, int flags);
90int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
91int sctp_inet_listen(struct socket *sock, int backlog);
92void sctp_write_space(struct sock *sk);
93void sctp_data_ready(struct sock *sk);
94__poll_t sctp_poll(struct file *file, struct socket *sock,
95 poll_table *wait);
96void sctp_sock_rfree(struct sk_buff *skb);
97void sctp_copy_sock(struct sock *newsk, struct sock *sk,
98 struct sctp_association *asoc);
99extern struct percpu_counter sctp_sockets_allocated;
100int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
101struct sk_buff *sctp_skb_recv_datagram(struct sock *, int, int *);
102
103typedef int (*sctp_callback_t)(struct sctp_endpoint *, struct sctp_transport *, void *);
104void sctp_transport_walk_start(struct rhashtable_iter *iter);
105void sctp_transport_walk_stop(struct rhashtable_iter *iter);
106struct sctp_transport *sctp_transport_get_next(struct net *net,
107 struct rhashtable_iter *iter);
108struct sctp_transport *sctp_transport_get_idx(struct net *net,
109 struct rhashtable_iter *iter, int pos);
110int 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);
113int sctp_transport_traverse_process(sctp_callback_t cb, sctp_callback_t cb_done,
114 struct net *net, int *pos, void *p);
115int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *), void *p);
116int sctp_get_sctp_info(struct sock *sk, struct sctp_association *asoc,
117 struct sctp_info *info);
118
119/*
120 * sctp/primitive.c
121 */
122int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
123int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
124int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
125int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
126int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
127int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
128int sctp_primitive_RECONF(struct net *net, struct sctp_association *asoc,
129 void *arg);
130
131/*
132 * sctp/input.c
133 */
134int sctp_rcv(struct sk_buff *skb);
135int sctp_v4_err(struct sk_buff *skb, u32 info);
136int sctp_hash_endpoint(struct sctp_endpoint *ep);
137void sctp_unhash_endpoint(struct sctp_endpoint *);
138struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
139 struct sctphdr *, struct sctp_association **,
140 struct sctp_transport **);
141void sctp_err_finish(struct sock *, struct sctp_transport *);
142int sctp_udp_v4_err(struct sock *sk, struct sk_buff *skb);
143int sctp_udp_v6_err(struct sock *sk, struct sk_buff *skb);
144void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
145 struct sctp_transport *t, __u32 pmtu);
146void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
147 struct sk_buff *);
148void sctp_icmp_proto_unreachable(struct sock *sk,
149 struct sctp_association *asoc,
150 struct sctp_transport *t);
151int sctp_transport_hashtable_init(void);
152void sctp_transport_hashtable_destroy(void);
153int sctp_hash_transport(struct sctp_transport *t);
154void sctp_unhash_transport(struct sctp_transport *t);
155struct 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);
160struct sctp_transport *sctp_epaddr_lookup_transport(
161 const struct sctp_endpoint *ep,
162 const union sctp_addr *paddr);
163bool sctp_sk_bound_dev_eq(struct net *net, int bound_dev_if, int dif, int sdif);
164
165/*
166 * sctp/proc.c
167 */
168int __net_init sctp_proc_init(struct net *net);
169
170/*
171 * sctp/offload.c
172 */
173int sctp_offload_init(void);
174
175/*
176 * sctp/stream_sched.c
177 */
178void sctp_sched_ops_init(void);
179
180/*
181 * sctp/stream.c
182 */
183int sctp_send_reset_streams(struct sctp_association *asoc,
184 struct sctp_reset_streams *params);
185int sctp_send_reset_assoc(struct sctp_association *asoc);
186int 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 */
196extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
197extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
198extern long sysctl_sctp_mem[3];
199extern int sysctl_sctp_rmem[3];
200extern 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 */
212enum {
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
251struct sctp_mib {
252 unsigned long mibs[SCTP_MIB_MAX];
253};
254
255/* helper function to track stats about max rto and related transport */
256static 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
273extern atomic_t sctp_dbg_objcnt_sock;
274extern atomic_t sctp_dbg_objcnt_ep;
275extern atomic_t sctp_dbg_objcnt_assoc;
276extern atomic_t sctp_dbg_objcnt_transport;
277extern atomic_t sctp_dbg_objcnt_chunk;
278extern atomic_t sctp_dbg_objcnt_bind_addr;
279extern atomic_t sctp_dbg_objcnt_bind_bucket;
280extern atomic_t sctp_dbg_objcnt_addr;
281extern atomic_t sctp_dbg_objcnt_datamsg;
282extern atomic_t sctp_dbg_objcnt_keys;
283
284/* Macros to atomically increment/decrement objcnt counters. */
285#define SCTP_DBG_OBJCNT_INC(name) \
286atomic_inc(&sctp_dbg_objcnt_## name)
287#define SCTP_DBG_OBJCNT_DEC(name) \
288atomic_dec(&sctp_dbg_objcnt_## name)
289#define SCTP_DBG_OBJCNT(name) \
290atomic_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
298void 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
305static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
306
307#endif /* CONFIG_SCTP_DBG_OBJCOUNT */
308
309#if defined CONFIG_SYSCTL
310void sctp_sysctl_register(void);
311void sctp_sysctl_unregister(void);
312int sctp_sysctl_net_register(struct net *net);
313void sctp_sysctl_net_unregister(struct net *net);
314#else
315static inline void sctp_sysctl_register(void) { return; }
316static inline void sctp_sysctl_unregister(void) { return; }
317static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
318static 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
326void sctp_v6_pf_init(void);
327void sctp_v6_pf_exit(void);
328int sctp_v6_protosw_init(void);
329void sctp_v6_protosw_exit(void);
330int sctp_v6_add_protocol(void);
331void sctp_v6_del_protocol(void);
332
333#else /* #ifdef defined(CONFIG_IPV6) */
334
335static inline void sctp_v6_pf_init(void) { return; }
336static inline void sctp_v6_pf_exit(void) { return; }
337static inline int sctp_v6_protosw_init(void) { return 0; }
338static inline void sctp_v6_protosw_exit(void) { return; }
339static inline int sctp_v6_add_protocol(void) { return 0; }
340static 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. */
346static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
347{
348 return asoc ? asoc->assoc_id : 0;
349}
350
351static inline enum sctp_sstat_state
352sctp_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. */
365struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
366
367int 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
381static 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 */
396static 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. */
411static inline int sctp_list_single_entry(struct list_head *head)
412{
413 return list_is_singular(head);
414}
415
416static 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)\
430for (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)\
441for (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)\
453for (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
459extern struct proto sctp_prot;
460extern struct proto sctpv6_prot;
461void sctp_put_port(struct sock *sk);
462
463extern struct idr sctp_assocs_id;
464extern spinlock_t sctp_assocs_id_lock;
465
466/* Static inline functions. */
467
468/* Convert from an IP version number to an Address Family symbol. */
469static 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. */
482static 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. */
496static 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. */
502static 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))
512static 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))
520static 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))
528static 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 */
535static 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 */
543static 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 */
561static 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 */
572static 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
592static 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
598static 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
604static 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
616static 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
621static 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
627static 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
646static 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
657static inline bool sctp_transport_pl_enabled(struct sctp_transport *t)
658{
659 return t->pl.state != SCTP_PL_DISABLED;
660}
661
662static inline bool sctp_newsk_ready(const struct sock *sk)
663{
664 return sock_flag(sk, SOCK_DEAD) || sk->sk_socket;
665}
666
667static 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__ */