xref: /openbmc/linux/include/net/sock.h (revision a1e58bbd)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Definitions for the AF_INET socket handler.
7  *
8  * Version:	@(#)sock.h	1.0.4	05/13/93
9  *
10  * Authors:	Ross Biro
11  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  *		Corey Minyard <wf-rch!minyard@relay.EU.net>
13  *		Florian La Roche <flla@stud.uni-sb.de>
14  *
15  * Fixes:
16  *		Alan Cox	:	Volatiles in skbuff pointers. See
17  *					skbuff comments. May be overdone,
18  *					better to prove they can be removed
19  *					than the reverse.
20  *		Alan Cox	:	Added a zapped field for tcp to note
21  *					a socket is reset and must stay shut up
22  *		Alan Cox	:	New fields for options
23  *	Pauline Middelink	:	identd support
24  *		Alan Cox	:	Eliminate low level recv/recvfrom
25  *		David S. Miller	:	New socket lookup architecture.
26  *              Steve Whitehouse:       Default routines for sock_ops
27  *              Arnaldo C. Melo :	removed net_pinfo, tp_pinfo and made
28  *              			protinfo be just a void pointer, as the
29  *              			protocol specific parts were moved to
30  *              			respective headers and ipv4/v6, etc now
31  *              			use private slabcaches for its socks
32  *              Pedro Hortas	:	New flags field for socket options
33  *
34  *
35  *		This program is free software; you can redistribute it and/or
36  *		modify it under the terms of the GNU General Public License
37  *		as published by the Free Software Foundation; either version
38  *		2 of the License, or (at your option) any later version.
39  */
40 #ifndef _SOCK_H
41 #define _SOCK_H
42 
43 #include <linux/kernel.h>
44 #include <linux/list.h>
45 #include <linux/timer.h>
46 #include <linux/cache.h>
47 #include <linux/module.h>
48 #include <linux/lockdep.h>
49 #include <linux/netdevice.h>
50 #include <linux/pcounter.h>
51 #include <linux/skbuff.h>	/* struct sk_buff */
52 #include <linux/mm.h>
53 #include <linux/security.h>
54 
55 #include <linux/filter.h>
56 
57 #include <asm/atomic.h>
58 #include <net/dst.h>
59 #include <net/checksum.h>
60 
61 /*
62  * This structure really needs to be cleaned up.
63  * Most of it is for TCP, and not used by any of
64  * the other protocols.
65  */
66 
67 /* Define this to get the SOCK_DBG debugging facility. */
68 #define SOCK_DEBUGGING
69 #ifdef SOCK_DEBUGGING
70 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
71 					printk(KERN_DEBUG msg); } while (0)
72 #else
73 #define SOCK_DEBUG(sk, msg...) do { } while (0)
74 #endif
75 
76 /* This is the per-socket lock.  The spinlock provides a synchronization
77  * between user contexts and software interrupt processing, whereas the
78  * mini-semaphore synchronizes multiple users amongst themselves.
79  */
80 typedef struct {
81 	spinlock_t		slock;
82 	int			owned;
83 	wait_queue_head_t	wq;
84 	/*
85 	 * We express the mutex-alike socket_lock semantics
86 	 * to the lock validator by explicitly managing
87 	 * the slock as a lock variant (in addition to
88 	 * the slock itself):
89 	 */
90 #ifdef CONFIG_DEBUG_LOCK_ALLOC
91 	struct lockdep_map dep_map;
92 #endif
93 } socket_lock_t;
94 
95 struct sock;
96 struct proto;
97 struct net;
98 
99 /**
100  *	struct sock_common - minimal network layer representation of sockets
101  *	@skc_family: network address family
102  *	@skc_state: Connection state
103  *	@skc_reuse: %SO_REUSEADDR setting
104  *	@skc_bound_dev_if: bound device index if != 0
105  *	@skc_node: main hash linkage for various protocol lookup tables
106  *	@skc_bind_node: bind hash linkage for various protocol lookup tables
107  *	@skc_refcnt: reference count
108  *	@skc_hash: hash value used with various protocol lookup tables
109  *	@skc_prot: protocol handlers inside a network family
110  *	@skc_net: reference to the network namespace of this socket
111  *
112  *	This is the minimal network layer representation of sockets, the header
113  *	for struct sock and struct inet_timewait_sock.
114  */
115 struct sock_common {
116 	unsigned short		skc_family;
117 	volatile unsigned char	skc_state;
118 	unsigned char		skc_reuse;
119 	int			skc_bound_dev_if;
120 	struct hlist_node	skc_node;
121 	struct hlist_node	skc_bind_node;
122 	atomic_t		skc_refcnt;
123 	unsigned int		skc_hash;
124 	struct proto		*skc_prot;
125 	struct net	 	*skc_net;
126 };
127 
128 /**
129   *	struct sock - network layer representation of sockets
130   *	@__sk_common: shared layout with inet_timewait_sock
131   *	@sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
132   *	@sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
133   *	@sk_lock:	synchronizer
134   *	@sk_rcvbuf: size of receive buffer in bytes
135   *	@sk_sleep: sock wait queue
136   *	@sk_dst_cache: destination cache
137   *	@sk_dst_lock: destination cache lock
138   *	@sk_policy: flow policy
139   *	@sk_rmem_alloc: receive queue bytes committed
140   *	@sk_receive_queue: incoming packets
141   *	@sk_wmem_alloc: transmit queue bytes committed
142   *	@sk_write_queue: Packet sending queue
143   *	@sk_async_wait_queue: DMA copied packets
144   *	@sk_omem_alloc: "o" is "option" or "other"
145   *	@sk_wmem_queued: persistent queue size
146   *	@sk_forward_alloc: space allocated forward
147   *	@sk_allocation: allocation mode
148   *	@sk_sndbuf: size of send buffer in bytes
149   *	@sk_flags: %SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
150   *		   %SO_OOBINLINE settings
151   *	@sk_no_check: %SO_NO_CHECK setting, wether or not checkup packets
152   *	@sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
153   *	@sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
154   *	@sk_lingertime: %SO_LINGER l_linger setting
155   *	@sk_backlog: always used with the per-socket spinlock held
156   *	@sk_callback_lock: used with the callbacks in the end of this struct
157   *	@sk_error_queue: rarely used
158   *	@sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
159   *			  IPV6_ADDRFORM for instance)
160   *	@sk_err: last error
161   *	@sk_err_soft: errors that don't cause failure but are the cause of a
162   *		      persistent failure not just 'timed out'
163   *	@sk_drops: raw drops counter
164   *	@sk_ack_backlog: current listen backlog
165   *	@sk_max_ack_backlog: listen backlog set in listen()
166   *	@sk_priority: %SO_PRIORITY setting
167   *	@sk_type: socket type (%SOCK_STREAM, etc)
168   *	@sk_protocol: which protocol this socket belongs in this network family
169   *	@sk_peercred: %SO_PEERCRED setting
170   *	@sk_rcvlowat: %SO_RCVLOWAT setting
171   *	@sk_rcvtimeo: %SO_RCVTIMEO setting
172   *	@sk_sndtimeo: %SO_SNDTIMEO setting
173   *	@sk_filter: socket filtering instructions
174   *	@sk_protinfo: private area, net family specific, when not using slab
175   *	@sk_timer: sock cleanup timer
176   *	@sk_stamp: time stamp of last packet received
177   *	@sk_socket: Identd and reporting IO signals
178   *	@sk_user_data: RPC layer private data
179   *	@sk_sndmsg_page: cached page for sendmsg
180   *	@sk_sndmsg_off: cached offset for sendmsg
181   *	@sk_send_head: front of stuff to transmit
182   *	@sk_security: used by security modules
183   *	@sk_mark: generic packet mark
184   *	@sk_write_pending: a write to stream socket waits to start
185   *	@sk_state_change: callback to indicate change in the state of the sock
186   *	@sk_data_ready: callback to indicate there is data to be processed
187   *	@sk_write_space: callback to indicate there is bf sending space available
188   *	@sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
189   *	@sk_backlog_rcv: callback to process the backlog
190   *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
191  */
192 struct sock {
193 	/*
194 	 * Now struct inet_timewait_sock also uses sock_common, so please just
195 	 * don't add nothing before this first member (__sk_common) --acme
196 	 */
197 	struct sock_common	__sk_common;
198 #define sk_family		__sk_common.skc_family
199 #define sk_state		__sk_common.skc_state
200 #define sk_reuse		__sk_common.skc_reuse
201 #define sk_bound_dev_if		__sk_common.skc_bound_dev_if
202 #define sk_node			__sk_common.skc_node
203 #define sk_bind_node		__sk_common.skc_bind_node
204 #define sk_refcnt		__sk_common.skc_refcnt
205 #define sk_hash			__sk_common.skc_hash
206 #define sk_prot			__sk_common.skc_prot
207 #define sk_net			__sk_common.skc_net
208 	unsigned char		sk_shutdown : 2,
209 				sk_no_check : 2,
210 				sk_userlocks : 4;
211 	unsigned char		sk_protocol;
212 	unsigned short		sk_type;
213 	int			sk_rcvbuf;
214 	socket_lock_t		sk_lock;
215 	/*
216 	 * The backlog queue is special, it is always used with
217 	 * the per-socket spinlock held and requires low latency
218 	 * access. Therefore we special case it's implementation.
219 	 */
220 	struct {
221 		struct sk_buff *head;
222 		struct sk_buff *tail;
223 	} sk_backlog;
224 	wait_queue_head_t	*sk_sleep;
225 	struct dst_entry	*sk_dst_cache;
226 	struct xfrm_policy	*sk_policy[2];
227 	rwlock_t		sk_dst_lock;
228 	atomic_t		sk_rmem_alloc;
229 	atomic_t		sk_wmem_alloc;
230 	atomic_t		sk_omem_alloc;
231 	int			sk_sndbuf;
232 	struct sk_buff_head	sk_receive_queue;
233 	struct sk_buff_head	sk_write_queue;
234 	struct sk_buff_head	sk_async_wait_queue;
235 	int			sk_wmem_queued;
236 	int			sk_forward_alloc;
237 	gfp_t			sk_allocation;
238 	int			sk_route_caps;
239 	int			sk_gso_type;
240 	int			sk_rcvlowat;
241 	unsigned long 		sk_flags;
242 	unsigned long	        sk_lingertime;
243 	struct sk_buff_head	sk_error_queue;
244 	struct proto		*sk_prot_creator;
245 	rwlock_t		sk_callback_lock;
246 	int			sk_err,
247 				sk_err_soft;
248 	atomic_t		sk_drops;
249 	unsigned short		sk_ack_backlog;
250 	unsigned short		sk_max_ack_backlog;
251 	__u32			sk_priority;
252 	struct ucred		sk_peercred;
253 	long			sk_rcvtimeo;
254 	long			sk_sndtimeo;
255 	struct sk_filter      	*sk_filter;
256 	void			*sk_protinfo;
257 	struct timer_list	sk_timer;
258 	ktime_t			sk_stamp;
259 	struct socket		*sk_socket;
260 	void			*sk_user_data;
261 	struct page		*sk_sndmsg_page;
262 	struct sk_buff		*sk_send_head;
263 	__u32			sk_sndmsg_off;
264 	int			sk_write_pending;
265 	void			*sk_security;
266 	__u32			sk_mark;
267 	/* XXX 4 bytes hole on 64 bit */
268 	void			(*sk_state_change)(struct sock *sk);
269 	void			(*sk_data_ready)(struct sock *sk, int bytes);
270 	void			(*sk_write_space)(struct sock *sk);
271 	void			(*sk_error_report)(struct sock *sk);
272   	int			(*sk_backlog_rcv)(struct sock *sk,
273 						  struct sk_buff *skb);
274 	void                    (*sk_destruct)(struct sock *sk);
275 };
276 
277 /*
278  * Hashed lists helper routines
279  */
280 static inline struct sock *__sk_head(const struct hlist_head *head)
281 {
282 	return hlist_entry(head->first, struct sock, sk_node);
283 }
284 
285 static inline struct sock *sk_head(const struct hlist_head *head)
286 {
287 	return hlist_empty(head) ? NULL : __sk_head(head);
288 }
289 
290 static inline struct sock *sk_next(const struct sock *sk)
291 {
292 	return sk->sk_node.next ?
293 		hlist_entry(sk->sk_node.next, struct sock, sk_node) : NULL;
294 }
295 
296 static inline int sk_unhashed(const struct sock *sk)
297 {
298 	return hlist_unhashed(&sk->sk_node);
299 }
300 
301 static inline int sk_hashed(const struct sock *sk)
302 {
303 	return !sk_unhashed(sk);
304 }
305 
306 static __inline__ void sk_node_init(struct hlist_node *node)
307 {
308 	node->pprev = NULL;
309 }
310 
311 static __inline__ void __sk_del_node(struct sock *sk)
312 {
313 	__hlist_del(&sk->sk_node);
314 }
315 
316 static __inline__ int __sk_del_node_init(struct sock *sk)
317 {
318 	if (sk_hashed(sk)) {
319 		__sk_del_node(sk);
320 		sk_node_init(&sk->sk_node);
321 		return 1;
322 	}
323 	return 0;
324 }
325 
326 /* Grab socket reference count. This operation is valid only
327    when sk is ALREADY grabbed f.e. it is found in hash table
328    or a list and the lookup is made under lock preventing hash table
329    modifications.
330  */
331 
332 static inline void sock_hold(struct sock *sk)
333 {
334 	atomic_inc(&sk->sk_refcnt);
335 }
336 
337 /* Ungrab socket in the context, which assumes that socket refcnt
338    cannot hit zero, f.e. it is true in context of any socketcall.
339  */
340 static inline void __sock_put(struct sock *sk)
341 {
342 	atomic_dec(&sk->sk_refcnt);
343 }
344 
345 static __inline__ int sk_del_node_init(struct sock *sk)
346 {
347 	int rc = __sk_del_node_init(sk);
348 
349 	if (rc) {
350 		/* paranoid for a while -acme */
351 		WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
352 		__sock_put(sk);
353 	}
354 	return rc;
355 }
356 
357 static __inline__ void __sk_add_node(struct sock *sk, struct hlist_head *list)
358 {
359 	hlist_add_head(&sk->sk_node, list);
360 }
361 
362 static __inline__ void sk_add_node(struct sock *sk, struct hlist_head *list)
363 {
364 	sock_hold(sk);
365 	__sk_add_node(sk, list);
366 }
367 
368 static __inline__ void __sk_del_bind_node(struct sock *sk)
369 {
370 	__hlist_del(&sk->sk_bind_node);
371 }
372 
373 static __inline__ void sk_add_bind_node(struct sock *sk,
374 					struct hlist_head *list)
375 {
376 	hlist_add_head(&sk->sk_bind_node, list);
377 }
378 
379 #define sk_for_each(__sk, node, list) \
380 	hlist_for_each_entry(__sk, node, list, sk_node)
381 #define sk_for_each_from(__sk, node) \
382 	if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
383 		hlist_for_each_entry_from(__sk, node, sk_node)
384 #define sk_for_each_continue(__sk, node) \
385 	if (__sk && ({ node = &(__sk)->sk_node; 1; })) \
386 		hlist_for_each_entry_continue(__sk, node, sk_node)
387 #define sk_for_each_safe(__sk, node, tmp, list) \
388 	hlist_for_each_entry_safe(__sk, node, tmp, list, sk_node)
389 #define sk_for_each_bound(__sk, node, list) \
390 	hlist_for_each_entry(__sk, node, list, sk_bind_node)
391 
392 /* Sock flags */
393 enum sock_flags {
394 	SOCK_DEAD,
395 	SOCK_DONE,
396 	SOCK_URGINLINE,
397 	SOCK_KEEPOPEN,
398 	SOCK_LINGER,
399 	SOCK_DESTROY,
400 	SOCK_BROADCAST,
401 	SOCK_TIMESTAMP,
402 	SOCK_ZAPPED,
403 	SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
404 	SOCK_DBG, /* %SO_DEBUG setting */
405 	SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
406 	SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
407 	SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
408 	SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
409 };
410 
411 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
412 {
413 	nsk->sk_flags = osk->sk_flags;
414 }
415 
416 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
417 {
418 	__set_bit(flag, &sk->sk_flags);
419 }
420 
421 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
422 {
423 	__clear_bit(flag, &sk->sk_flags);
424 }
425 
426 static inline int sock_flag(struct sock *sk, enum sock_flags flag)
427 {
428 	return test_bit(flag, &sk->sk_flags);
429 }
430 
431 static inline void sk_acceptq_removed(struct sock *sk)
432 {
433 	sk->sk_ack_backlog--;
434 }
435 
436 static inline void sk_acceptq_added(struct sock *sk)
437 {
438 	sk->sk_ack_backlog++;
439 }
440 
441 static inline int sk_acceptq_is_full(struct sock *sk)
442 {
443 	return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
444 }
445 
446 /*
447  * Compute minimal free write space needed to queue new packets.
448  */
449 static inline int sk_stream_min_wspace(struct sock *sk)
450 {
451 	return sk->sk_wmem_queued >> 1;
452 }
453 
454 static inline int sk_stream_wspace(struct sock *sk)
455 {
456 	return sk->sk_sndbuf - sk->sk_wmem_queued;
457 }
458 
459 extern void sk_stream_write_space(struct sock *sk);
460 
461 static inline int sk_stream_memory_free(struct sock *sk)
462 {
463 	return sk->sk_wmem_queued < sk->sk_sndbuf;
464 }
465 
466 /* The per-socket spinlock must be held here. */
467 static inline void sk_add_backlog(struct sock *sk, struct sk_buff *skb)
468 {
469 	if (!sk->sk_backlog.tail) {
470 		sk->sk_backlog.head = sk->sk_backlog.tail = skb;
471 	} else {
472 		sk->sk_backlog.tail->next = skb;
473 		sk->sk_backlog.tail = skb;
474 	}
475 	skb->next = NULL;
476 }
477 
478 #define sk_wait_event(__sk, __timeo, __condition)			\
479 	({	int __rc;						\
480 		release_sock(__sk);					\
481 		__rc = __condition;					\
482 		if (!__rc) {						\
483 			*(__timeo) = schedule_timeout(*(__timeo));	\
484 		}							\
485 		lock_sock(__sk);					\
486 		__rc = __condition;					\
487 		__rc;							\
488 	})
489 
490 extern int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
491 extern int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
492 extern void sk_stream_wait_close(struct sock *sk, long timeo_p);
493 extern int sk_stream_error(struct sock *sk, int flags, int err);
494 extern void sk_stream_kill_queues(struct sock *sk);
495 
496 extern int sk_wait_data(struct sock *sk, long *timeo);
497 
498 struct request_sock_ops;
499 struct timewait_sock_ops;
500 struct inet_hashinfo;
501 
502 /* Networking protocol blocks we attach to sockets.
503  * socket layer -> transport layer interface
504  * transport -> network interface is defined by struct inet_proto
505  */
506 struct proto {
507 	void			(*close)(struct sock *sk,
508 					long timeout);
509 	int			(*connect)(struct sock *sk,
510 				        struct sockaddr *uaddr,
511 					int addr_len);
512 	int			(*disconnect)(struct sock *sk, int flags);
513 
514 	struct sock *		(*accept) (struct sock *sk, int flags, int *err);
515 
516 	int			(*ioctl)(struct sock *sk, int cmd,
517 					 unsigned long arg);
518 	int			(*init)(struct sock *sk);
519 	int			(*destroy)(struct sock *sk);
520 	void			(*shutdown)(struct sock *sk, int how);
521 	int			(*setsockopt)(struct sock *sk, int level,
522 					int optname, char __user *optval,
523 					int optlen);
524 	int			(*getsockopt)(struct sock *sk, int level,
525 					int optname, char __user *optval,
526 					int __user *option);
527 	int			(*compat_setsockopt)(struct sock *sk,
528 					int level,
529 					int optname, char __user *optval,
530 					int optlen);
531 	int			(*compat_getsockopt)(struct sock *sk,
532 					int level,
533 					int optname, char __user *optval,
534 					int __user *option);
535 	int			(*sendmsg)(struct kiocb *iocb, struct sock *sk,
536 					   struct msghdr *msg, size_t len);
537 	int			(*recvmsg)(struct kiocb *iocb, struct sock *sk,
538 					   struct msghdr *msg,
539 					size_t len, int noblock, int flags,
540 					int *addr_len);
541 	int			(*sendpage)(struct sock *sk, struct page *page,
542 					int offset, size_t size, int flags);
543 	int			(*bind)(struct sock *sk,
544 					struct sockaddr *uaddr, int addr_len);
545 
546 	int			(*backlog_rcv) (struct sock *sk,
547 						struct sk_buff *skb);
548 
549 	/* Keeping track of sk's, looking them up, and port selection methods. */
550 	void			(*hash)(struct sock *sk);
551 	void			(*unhash)(struct sock *sk);
552 	int			(*get_port)(struct sock *sk, unsigned short snum);
553 
554 	/* Keeping track of sockets in use */
555 #ifdef CONFIG_PROC_FS
556 	struct pcounter		inuse;
557 #endif
558 
559 	/* Memory pressure */
560 	void			(*enter_memory_pressure)(void);
561 	atomic_t		*memory_allocated;	/* Current allocated memory. */
562 	atomic_t		*sockets_allocated;	/* Current number of sockets. */
563 	/*
564 	 * Pressure flag: try to collapse.
565 	 * Technical note: it is used by multiple contexts non atomically.
566 	 * All the __sk_mem_schedule() is of this nature: accounting
567 	 * is strict, actions are advisory and have some latency.
568 	 */
569 	int			*memory_pressure;
570 	int			*sysctl_mem;
571 	int			*sysctl_wmem;
572 	int			*sysctl_rmem;
573 	int			max_header;
574 
575 	struct kmem_cache		*slab;
576 	unsigned int		obj_size;
577 
578 	atomic_t		*orphan_count;
579 
580 	struct request_sock_ops	*rsk_prot;
581 	struct timewait_sock_ops *twsk_prot;
582 
583 	struct inet_hashinfo	*hashinfo;
584 
585 	struct module		*owner;
586 
587 	char			name[32];
588 
589 	struct list_head	node;
590 #ifdef SOCK_REFCNT_DEBUG
591 	atomic_t		socks;
592 #endif
593 };
594 
595 extern int proto_register(struct proto *prot, int alloc_slab);
596 extern void proto_unregister(struct proto *prot);
597 
598 #ifdef SOCK_REFCNT_DEBUG
599 static inline void sk_refcnt_debug_inc(struct sock *sk)
600 {
601 	atomic_inc(&sk->sk_prot->socks);
602 }
603 
604 static inline void sk_refcnt_debug_dec(struct sock *sk)
605 {
606 	atomic_dec(&sk->sk_prot->socks);
607 	printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
608 	       sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
609 }
610 
611 static inline void sk_refcnt_debug_release(const struct sock *sk)
612 {
613 	if (atomic_read(&sk->sk_refcnt) != 1)
614 		printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
615 		       sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
616 }
617 #else /* SOCK_REFCNT_DEBUG */
618 #define sk_refcnt_debug_inc(sk) do { } while (0)
619 #define sk_refcnt_debug_dec(sk) do { } while (0)
620 #define sk_refcnt_debug_release(sk) do { } while (0)
621 #endif /* SOCK_REFCNT_DEBUG */
622 
623 
624 #ifdef CONFIG_PROC_FS
625 # define DEFINE_PROTO_INUSE(NAME) DEFINE_PCOUNTER(NAME)
626 # define REF_PROTO_INUSE(NAME) PCOUNTER_MEMBER_INITIALIZER(NAME, .inuse)
627 /* Called with local bh disabled */
628 static inline void sock_prot_inuse_add(struct proto *prot, int inc)
629 {
630 	pcounter_add(&prot->inuse, inc);
631 }
632 static inline int sock_prot_inuse_init(struct proto *proto)
633 {
634 	return pcounter_alloc(&proto->inuse);
635 }
636 static inline int sock_prot_inuse_get(struct proto *proto)
637 {
638 	return pcounter_getval(&proto->inuse);
639 }
640 static inline void sock_prot_inuse_free(struct proto *proto)
641 {
642 	pcounter_free(&proto->inuse);
643 }
644 #else
645 # define DEFINE_PROTO_INUSE(NAME)
646 # define REF_PROTO_INUSE(NAME)
647 static void inline sock_prot_inuse_add(struct proto *prot, int inc)
648 {
649 }
650 static int inline sock_prot_inuse_init(struct proto *proto)
651 {
652 	return 0;
653 }
654 static void inline sock_prot_inuse_free(struct proto *proto)
655 {
656 }
657 #endif
658 
659 
660 /* With per-bucket locks this operation is not-atomic, so that
661  * this version is not worse.
662  */
663 static inline void __sk_prot_rehash(struct sock *sk)
664 {
665 	sk->sk_prot->unhash(sk);
666 	sk->sk_prot->hash(sk);
667 }
668 
669 /* About 10 seconds */
670 #define SOCK_DESTROY_TIME (10*HZ)
671 
672 /* Sockets 0-1023 can't be bound to unless you are superuser */
673 #define PROT_SOCK	1024
674 
675 #define SHUTDOWN_MASK	3
676 #define RCV_SHUTDOWN	1
677 #define SEND_SHUTDOWN	2
678 
679 #define SOCK_SNDBUF_LOCK	1
680 #define SOCK_RCVBUF_LOCK	2
681 #define SOCK_BINDADDR_LOCK	4
682 #define SOCK_BINDPORT_LOCK	8
683 
684 /* sock_iocb: used to kick off async processing of socket ios */
685 struct sock_iocb {
686 	struct list_head	list;
687 
688 	int			flags;
689 	int			size;
690 	struct socket		*sock;
691 	struct sock		*sk;
692 	struct scm_cookie	*scm;
693 	struct msghdr		*msg, async_msg;
694 	struct kiocb		*kiocb;
695 };
696 
697 static inline struct sock_iocb *kiocb_to_siocb(struct kiocb *iocb)
698 {
699 	return (struct sock_iocb *)iocb->private;
700 }
701 
702 static inline struct kiocb *siocb_to_kiocb(struct sock_iocb *si)
703 {
704 	return si->kiocb;
705 }
706 
707 struct socket_alloc {
708 	struct socket socket;
709 	struct inode vfs_inode;
710 };
711 
712 static inline struct socket *SOCKET_I(struct inode *inode)
713 {
714 	return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
715 }
716 
717 static inline struct inode *SOCK_INODE(struct socket *socket)
718 {
719 	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
720 }
721 
722 /*
723  * Functions for memory accounting
724  */
725 extern int __sk_mem_schedule(struct sock *sk, int size, int kind);
726 extern void __sk_mem_reclaim(struct sock *sk);
727 
728 #define SK_MEM_QUANTUM ((int)PAGE_SIZE)
729 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
730 #define SK_MEM_SEND	0
731 #define SK_MEM_RECV	1
732 
733 static inline int sk_mem_pages(int amt)
734 {
735 	return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
736 }
737 
738 static inline int sk_has_account(struct sock *sk)
739 {
740 	/* return true if protocol supports memory accounting */
741 	return !!sk->sk_prot->memory_allocated;
742 }
743 
744 static inline int sk_wmem_schedule(struct sock *sk, int size)
745 {
746 	if (!sk_has_account(sk))
747 		return 1;
748 	return size <= sk->sk_forward_alloc ||
749 		__sk_mem_schedule(sk, size, SK_MEM_SEND);
750 }
751 
752 static inline int sk_rmem_schedule(struct sock *sk, int size)
753 {
754 	if (!sk_has_account(sk))
755 		return 1;
756 	return size <= sk->sk_forward_alloc ||
757 		__sk_mem_schedule(sk, size, SK_MEM_RECV);
758 }
759 
760 static inline void sk_mem_reclaim(struct sock *sk)
761 {
762 	if (!sk_has_account(sk))
763 		return;
764 	if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
765 		__sk_mem_reclaim(sk);
766 }
767 
768 static inline void sk_mem_reclaim_partial(struct sock *sk)
769 {
770 	if (!sk_has_account(sk))
771 		return;
772 	if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
773 		__sk_mem_reclaim(sk);
774 }
775 
776 static inline void sk_mem_charge(struct sock *sk, int size)
777 {
778 	if (!sk_has_account(sk))
779 		return;
780 	sk->sk_forward_alloc -= size;
781 }
782 
783 static inline void sk_mem_uncharge(struct sock *sk, int size)
784 {
785 	if (!sk_has_account(sk))
786 		return;
787 	sk->sk_forward_alloc += size;
788 }
789 
790 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
791 {
792 	skb_truesize_check(skb);
793 	sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
794 	sk->sk_wmem_queued -= skb->truesize;
795 	sk_mem_uncharge(sk, skb->truesize);
796 	__kfree_skb(skb);
797 }
798 
799 /* Used by processes to "lock" a socket state, so that
800  * interrupts and bottom half handlers won't change it
801  * from under us. It essentially blocks any incoming
802  * packets, so that we won't get any new data or any
803  * packets that change the state of the socket.
804  *
805  * While locked, BH processing will add new packets to
806  * the backlog queue.  This queue is processed by the
807  * owner of the socket lock right before it is released.
808  *
809  * Since ~2.3.5 it is also exclusive sleep lock serializing
810  * accesses from user process context.
811  */
812 #define sock_owned_by_user(sk)	((sk)->sk_lock.owned)
813 
814 /*
815  * Macro so as to not evaluate some arguments when
816  * lockdep is not enabled.
817  *
818  * Mark both the sk_lock and the sk_lock.slock as a
819  * per-address-family lock class.
820  */
821 #define sock_lock_init_class_and_name(sk, sname, skey, name, key) 	\
822 do {									\
823 	sk->sk_lock.owned = 0;					\
824 	init_waitqueue_head(&sk->sk_lock.wq);				\
825 	spin_lock_init(&(sk)->sk_lock.slock);				\
826 	debug_check_no_locks_freed((void *)&(sk)->sk_lock,		\
827 			sizeof((sk)->sk_lock));				\
828 	lockdep_set_class_and_name(&(sk)->sk_lock.slock,		\
829 		       	(skey), (sname));				\
830 	lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);	\
831 } while (0)
832 
833 extern void lock_sock_nested(struct sock *sk, int subclass);
834 
835 static inline void lock_sock(struct sock *sk)
836 {
837 	lock_sock_nested(sk, 0);
838 }
839 
840 extern void release_sock(struct sock *sk);
841 
842 /* BH context may only use the following locking interface. */
843 #define bh_lock_sock(__sk)	spin_lock(&((__sk)->sk_lock.slock))
844 #define bh_lock_sock_nested(__sk) \
845 				spin_lock_nested(&((__sk)->sk_lock.slock), \
846 				SINGLE_DEPTH_NESTING)
847 #define bh_unlock_sock(__sk)	spin_unlock(&((__sk)->sk_lock.slock))
848 
849 extern struct sock		*sk_alloc(struct net *net, int family,
850 					  gfp_t priority,
851 					  struct proto *prot);
852 extern void			sk_free(struct sock *sk);
853 extern struct sock		*sk_clone(const struct sock *sk,
854 					  const gfp_t priority);
855 
856 extern struct sk_buff		*sock_wmalloc(struct sock *sk,
857 					      unsigned long size, int force,
858 					      gfp_t priority);
859 extern struct sk_buff		*sock_rmalloc(struct sock *sk,
860 					      unsigned long size, int force,
861 					      gfp_t priority);
862 extern void			sock_wfree(struct sk_buff *skb);
863 extern void			sock_rfree(struct sk_buff *skb);
864 
865 extern int			sock_setsockopt(struct socket *sock, int level,
866 						int op, char __user *optval,
867 						int optlen);
868 
869 extern int			sock_getsockopt(struct socket *sock, int level,
870 						int op, char __user *optval,
871 						int __user *optlen);
872 extern struct sk_buff 		*sock_alloc_send_skb(struct sock *sk,
873 						     unsigned long size,
874 						     int noblock,
875 						     int *errcode);
876 extern void *sock_kmalloc(struct sock *sk, int size,
877 			  gfp_t priority);
878 extern void sock_kfree_s(struct sock *sk, void *mem, int size);
879 extern void sk_send_sigurg(struct sock *sk);
880 
881 /*
882  * Functions to fill in entries in struct proto_ops when a protocol
883  * does not implement a particular function.
884  */
885 extern int                      sock_no_bind(struct socket *,
886 					     struct sockaddr *, int);
887 extern int                      sock_no_connect(struct socket *,
888 						struct sockaddr *, int, int);
889 extern int                      sock_no_socketpair(struct socket *,
890 						   struct socket *);
891 extern int                      sock_no_accept(struct socket *,
892 					       struct socket *, int);
893 extern int                      sock_no_getname(struct socket *,
894 						struct sockaddr *, int *, int);
895 extern unsigned int             sock_no_poll(struct file *, struct socket *,
896 					     struct poll_table_struct *);
897 extern int                      sock_no_ioctl(struct socket *, unsigned int,
898 					      unsigned long);
899 extern int			sock_no_listen(struct socket *, int);
900 extern int                      sock_no_shutdown(struct socket *, int);
901 extern int			sock_no_getsockopt(struct socket *, int , int,
902 						   char __user *, int __user *);
903 extern int			sock_no_setsockopt(struct socket *, int, int,
904 						   char __user *, int);
905 extern int                      sock_no_sendmsg(struct kiocb *, struct socket *,
906 						struct msghdr *, size_t);
907 extern int                      sock_no_recvmsg(struct kiocb *, struct socket *,
908 						struct msghdr *, size_t, int);
909 extern int			sock_no_mmap(struct file *file,
910 					     struct socket *sock,
911 					     struct vm_area_struct *vma);
912 extern ssize_t			sock_no_sendpage(struct socket *sock,
913 						struct page *page,
914 						int offset, size_t size,
915 						int flags);
916 
917 /*
918  * Functions to fill in entries in struct proto_ops when a protocol
919  * uses the inet style.
920  */
921 extern int sock_common_getsockopt(struct socket *sock, int level, int optname,
922 				  char __user *optval, int __user *optlen);
923 extern int sock_common_recvmsg(struct kiocb *iocb, struct socket *sock,
924 			       struct msghdr *msg, size_t size, int flags);
925 extern int sock_common_setsockopt(struct socket *sock, int level, int optname,
926 				  char __user *optval, int optlen);
927 extern int compat_sock_common_getsockopt(struct socket *sock, int level,
928 		int optname, char __user *optval, int __user *optlen);
929 extern int compat_sock_common_setsockopt(struct socket *sock, int level,
930 		int optname, char __user *optval, int optlen);
931 
932 extern void sk_common_release(struct sock *sk);
933 
934 /*
935  *	Default socket callbacks and setup code
936  */
937 
938 /* Initialise core socket variables */
939 extern void sock_init_data(struct socket *sock, struct sock *sk);
940 
941 /**
942  *	sk_filter - run a packet through a socket filter
943  *	@sk: sock associated with &sk_buff
944  *	@skb: buffer to filter
945  *	@needlock: set to 1 if the sock is not locked by caller.
946  *
947  * Run the filter code and then cut skb->data to correct size returned by
948  * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller
949  * than pkt_len we keep whole skb->data. This is the socket level
950  * wrapper to sk_run_filter. It returns 0 if the packet should
951  * be accepted or -EPERM if the packet should be tossed.
952  *
953  */
954 
955 static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
956 {
957 	int err;
958 	struct sk_filter *filter;
959 
960 	err = security_sock_rcv_skb(sk, skb);
961 	if (err)
962 		return err;
963 
964 	rcu_read_lock_bh();
965 	filter = rcu_dereference(sk->sk_filter);
966 	if (filter) {
967 		unsigned int pkt_len = sk_run_filter(skb, filter->insns,
968 				filter->len);
969 		err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
970 	}
971  	rcu_read_unlock_bh();
972 
973 	return err;
974 }
975 
976 /**
977  *	sk_filter_release: Release a socket filter
978  *	@sk: socket
979  *	@fp: filter to remove
980  *
981  *	Remove a filter from a socket and release its resources.
982  */
983 
984 static inline void sk_filter_release(struct sk_filter *fp)
985 {
986 	if (atomic_dec_and_test(&fp->refcnt))
987 		kfree(fp);
988 }
989 
990 static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)
991 {
992 	unsigned int size = sk_filter_len(fp);
993 
994 	atomic_sub(size, &sk->sk_omem_alloc);
995 	sk_filter_release(fp);
996 }
997 
998 static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
999 {
1000 	atomic_inc(&fp->refcnt);
1001 	atomic_add(sk_filter_len(fp), &sk->sk_omem_alloc);
1002 }
1003 
1004 /*
1005  * Socket reference counting postulates.
1006  *
1007  * * Each user of socket SHOULD hold a reference count.
1008  * * Each access point to socket (an hash table bucket, reference from a list,
1009  *   running timer, skb in flight MUST hold a reference count.
1010  * * When reference count hits 0, it means it will never increase back.
1011  * * When reference count hits 0, it means that no references from
1012  *   outside exist to this socket and current process on current CPU
1013  *   is last user and may/should destroy this socket.
1014  * * sk_free is called from any context: process, BH, IRQ. When
1015  *   it is called, socket has no references from outside -> sk_free
1016  *   may release descendant resources allocated by the socket, but
1017  *   to the time when it is called, socket is NOT referenced by any
1018  *   hash tables, lists etc.
1019  * * Packets, delivered from outside (from network or from another process)
1020  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1021  *   when they sit in queue. Otherwise, packets will leak to hole, when
1022  *   socket is looked up by one cpu and unhasing is made by another CPU.
1023  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1024  *   (leak to backlog). Packet socket does all the processing inside
1025  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1026  *   use separate SMP lock, so that they are prone too.
1027  */
1028 
1029 /* Ungrab socket and destroy it, if it was the last reference. */
1030 static inline void sock_put(struct sock *sk)
1031 {
1032 	if (atomic_dec_and_test(&sk->sk_refcnt))
1033 		sk_free(sk);
1034 }
1035 
1036 extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1037 			  const int nested);
1038 
1039 /* Detach socket from process context.
1040  * Announce socket dead, detach it from wait queue and inode.
1041  * Note that parent inode held reference count on this struct sock,
1042  * we do not release it in this function, because protocol
1043  * probably wants some additional cleanups or even continuing
1044  * to work with this socket (TCP).
1045  */
1046 static inline void sock_orphan(struct sock *sk)
1047 {
1048 	write_lock_bh(&sk->sk_callback_lock);
1049 	sock_set_flag(sk, SOCK_DEAD);
1050 	sk->sk_socket = NULL;
1051 	sk->sk_sleep  = NULL;
1052 	write_unlock_bh(&sk->sk_callback_lock);
1053 }
1054 
1055 static inline void sock_graft(struct sock *sk, struct socket *parent)
1056 {
1057 	write_lock_bh(&sk->sk_callback_lock);
1058 	sk->sk_sleep = &parent->wait;
1059 	parent->sk = sk;
1060 	sk->sk_socket = parent;
1061 	security_sock_graft(sk, parent);
1062 	write_unlock_bh(&sk->sk_callback_lock);
1063 }
1064 
1065 extern int sock_i_uid(struct sock *sk);
1066 extern unsigned long sock_i_ino(struct sock *sk);
1067 
1068 static inline struct dst_entry *
1069 __sk_dst_get(struct sock *sk)
1070 {
1071 	return sk->sk_dst_cache;
1072 }
1073 
1074 static inline struct dst_entry *
1075 sk_dst_get(struct sock *sk)
1076 {
1077 	struct dst_entry *dst;
1078 
1079 	read_lock(&sk->sk_dst_lock);
1080 	dst = sk->sk_dst_cache;
1081 	if (dst)
1082 		dst_hold(dst);
1083 	read_unlock(&sk->sk_dst_lock);
1084 	return dst;
1085 }
1086 
1087 static inline void
1088 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1089 {
1090 	struct dst_entry *old_dst;
1091 
1092 	old_dst = sk->sk_dst_cache;
1093 	sk->sk_dst_cache = dst;
1094 	dst_release(old_dst);
1095 }
1096 
1097 static inline void
1098 sk_dst_set(struct sock *sk, struct dst_entry *dst)
1099 {
1100 	write_lock(&sk->sk_dst_lock);
1101 	__sk_dst_set(sk, dst);
1102 	write_unlock(&sk->sk_dst_lock);
1103 }
1104 
1105 static inline void
1106 __sk_dst_reset(struct sock *sk)
1107 {
1108 	struct dst_entry *old_dst;
1109 
1110 	old_dst = sk->sk_dst_cache;
1111 	sk->sk_dst_cache = NULL;
1112 	dst_release(old_dst);
1113 }
1114 
1115 static inline void
1116 sk_dst_reset(struct sock *sk)
1117 {
1118 	write_lock(&sk->sk_dst_lock);
1119 	__sk_dst_reset(sk);
1120 	write_unlock(&sk->sk_dst_lock);
1121 }
1122 
1123 extern struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1124 
1125 extern struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1126 
1127 static inline int sk_can_gso(const struct sock *sk)
1128 {
1129 	return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
1130 }
1131 
1132 extern void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
1133 
1134 static inline int skb_copy_to_page(struct sock *sk, char __user *from,
1135 				   struct sk_buff *skb, struct page *page,
1136 				   int off, int copy)
1137 {
1138 	if (skb->ip_summed == CHECKSUM_NONE) {
1139 		int err = 0;
1140 		__wsum csum = csum_and_copy_from_user(from,
1141 						     page_address(page) + off,
1142 							    copy, 0, &err);
1143 		if (err)
1144 			return err;
1145 		skb->csum = csum_block_add(skb->csum, csum, skb->len);
1146 	} else if (copy_from_user(page_address(page) + off, from, copy))
1147 		return -EFAULT;
1148 
1149 	skb->len	     += copy;
1150 	skb->data_len	     += copy;
1151 	skb->truesize	     += copy;
1152 	sk->sk_wmem_queued   += copy;
1153 	sk_mem_charge(sk, copy);
1154 	return 0;
1155 }
1156 
1157 /*
1158  * 	Queue a received datagram if it will fit. Stream and sequenced
1159  *	protocols can't normally use this as they need to fit buffers in
1160  *	and play with them.
1161  *
1162  * 	Inlined as it's very short and called for pretty much every
1163  *	packet ever received.
1164  */
1165 
1166 static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1167 {
1168 	sock_hold(sk);
1169 	skb->sk = sk;
1170 	skb->destructor = sock_wfree;
1171 	atomic_add(skb->truesize, &sk->sk_wmem_alloc);
1172 }
1173 
1174 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
1175 {
1176 	skb->sk = sk;
1177 	skb->destructor = sock_rfree;
1178 	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
1179 	sk_mem_charge(sk, skb->truesize);
1180 }
1181 
1182 extern void sk_reset_timer(struct sock *sk, struct timer_list* timer,
1183 			   unsigned long expires);
1184 
1185 extern void sk_stop_timer(struct sock *sk, struct timer_list* timer);
1186 
1187 extern int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
1188 
1189 static inline int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
1190 {
1191 	/* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
1192 	   number of warnings when compiling with -W --ANK
1193 	 */
1194 	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
1195 	    (unsigned)sk->sk_rcvbuf)
1196 		return -ENOMEM;
1197 	skb_set_owner_r(skb, sk);
1198 	skb_queue_tail(&sk->sk_error_queue, skb);
1199 	if (!sock_flag(sk, SOCK_DEAD))
1200 		sk->sk_data_ready(sk, skb->len);
1201 	return 0;
1202 }
1203 
1204 /*
1205  *	Recover an error report and clear atomically
1206  */
1207 
1208 static inline int sock_error(struct sock *sk)
1209 {
1210 	int err;
1211 	if (likely(!sk->sk_err))
1212 		return 0;
1213 	err = xchg(&sk->sk_err, 0);
1214 	return -err;
1215 }
1216 
1217 static inline unsigned long sock_wspace(struct sock *sk)
1218 {
1219 	int amt = 0;
1220 
1221 	if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
1222 		amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
1223 		if (amt < 0)
1224 			amt = 0;
1225 	}
1226 	return amt;
1227 }
1228 
1229 static inline void sk_wake_async(struct sock *sk, int how, int band)
1230 {
1231 	if (sk->sk_socket && sk->sk_socket->fasync_list)
1232 		sock_wake_async(sk->sk_socket, how, band);
1233 }
1234 
1235 #define SOCK_MIN_SNDBUF 2048
1236 #define SOCK_MIN_RCVBUF 256
1237 
1238 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
1239 {
1240 	if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
1241 		sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
1242 		sk->sk_sndbuf = max(sk->sk_sndbuf, SOCK_MIN_SNDBUF);
1243 	}
1244 }
1245 
1246 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp);
1247 
1248 static inline struct page *sk_stream_alloc_page(struct sock *sk)
1249 {
1250 	struct page *page = NULL;
1251 
1252 	page = alloc_pages(sk->sk_allocation, 0);
1253 	if (!page) {
1254 		sk->sk_prot->enter_memory_pressure();
1255 		sk_stream_moderate_sndbuf(sk);
1256 	}
1257 	return page;
1258 }
1259 
1260 /*
1261  *	Default write policy as shown to user space via poll/select/SIGIO
1262  */
1263 static inline int sock_writeable(const struct sock *sk)
1264 {
1265 	return atomic_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
1266 }
1267 
1268 static inline gfp_t gfp_any(void)
1269 {
1270 	return in_atomic() ? GFP_ATOMIC : GFP_KERNEL;
1271 }
1272 
1273 static inline long sock_rcvtimeo(const struct sock *sk, int noblock)
1274 {
1275 	return noblock ? 0 : sk->sk_rcvtimeo;
1276 }
1277 
1278 static inline long sock_sndtimeo(const struct sock *sk, int noblock)
1279 {
1280 	return noblock ? 0 : sk->sk_sndtimeo;
1281 }
1282 
1283 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
1284 {
1285 	return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
1286 }
1287 
1288 /* Alas, with timeout socket operations are not restartable.
1289  * Compare this to poll().
1290  */
1291 static inline int sock_intr_errno(long timeo)
1292 {
1293 	return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
1294 }
1295 
1296 extern void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
1297 	struct sk_buff *skb);
1298 
1299 static __inline__ void
1300 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
1301 {
1302 	ktime_t kt = skb->tstamp;
1303 
1304 	if (sock_flag(sk, SOCK_RCVTSTAMP))
1305 		__sock_recv_timestamp(msg, sk, skb);
1306 	else
1307 		sk->sk_stamp = kt;
1308 }
1309 
1310 /**
1311  * sk_eat_skb - Release a skb if it is no longer needed
1312  * @sk: socket to eat this skb from
1313  * @skb: socket buffer to eat
1314  * @copied_early: flag indicating whether DMA operations copied this data early
1315  *
1316  * This routine must be called with interrupts disabled or with the socket
1317  * locked so that the sk_buff queue operation is ok.
1318 */
1319 #ifdef CONFIG_NET_DMA
1320 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_early)
1321 {
1322 	__skb_unlink(skb, &sk->sk_receive_queue);
1323 	if (!copied_early)
1324 		__kfree_skb(skb);
1325 	else
1326 		__skb_queue_tail(&sk->sk_async_wait_queue, skb);
1327 }
1328 #else
1329 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb, int copied_early)
1330 {
1331 	__skb_unlink(skb, &sk->sk_receive_queue);
1332 	__kfree_skb(skb);
1333 }
1334 #endif
1335 
1336 extern void sock_enable_timestamp(struct sock *sk);
1337 extern int sock_get_timestamp(struct sock *, struct timeval __user *);
1338 extern int sock_get_timestampns(struct sock *, struct timespec __user *);
1339 
1340 /*
1341  *	Enable debug/info messages
1342  */
1343 extern int net_msg_warn;
1344 #define NETDEBUG(fmt, args...) \
1345 	do { if (net_msg_warn) printk(fmt,##args); } while (0)
1346 
1347 #define LIMIT_NETDEBUG(fmt, args...) \
1348 	do { if (net_msg_warn && net_ratelimit()) printk(fmt,##args); } while(0)
1349 
1350 /*
1351  * Macros for sleeping on a socket. Use them like this:
1352  *
1353  * SOCK_SLEEP_PRE(sk)
1354  * if (condition)
1355  * 	schedule();
1356  * SOCK_SLEEP_POST(sk)
1357  *
1358  * N.B. These are now obsolete and were, afaik, only ever used in DECnet
1359  * and when the last use of them in DECnet has gone, I'm intending to
1360  * remove them.
1361  */
1362 
1363 #define SOCK_SLEEP_PRE(sk) 	{ struct task_struct *tsk = current; \
1364 				DECLARE_WAITQUEUE(wait, tsk); \
1365 				tsk->state = TASK_INTERRUPTIBLE; \
1366 				add_wait_queue((sk)->sk_sleep, &wait); \
1367 				release_sock(sk);
1368 
1369 #define SOCK_SLEEP_POST(sk)	tsk->state = TASK_RUNNING; \
1370 				remove_wait_queue((sk)->sk_sleep, &wait); \
1371 				lock_sock(sk); \
1372 				}
1373 
1374 extern __u32 sysctl_wmem_max;
1375 extern __u32 sysctl_rmem_max;
1376 
1377 extern void sk_init(void);
1378 
1379 extern int sysctl_optmem_max;
1380 
1381 extern __u32 sysctl_wmem_default;
1382 extern __u32 sysctl_rmem_default;
1383 
1384 #endif	/* _SOCK_H */
1385