xref: /openbmc/linux/include/net/sock.h (revision 99fee508)
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/hardirq.h>
44 #include <linux/kernel.h>
45 #include <linux/list.h>
46 #include <linux/list_nulls.h>
47 #include <linux/timer.h>
48 #include <linux/cache.h>
49 #include <linux/bitops.h>
50 #include <linux/lockdep.h>
51 #include <linux/netdevice.h>
52 #include <linux/skbuff.h>	/* struct sk_buff */
53 #include <linux/mm.h>
54 #include <linux/security.h>
55 #include <linux/slab.h>
56 #include <linux/uaccess.h>
57 #include <linux/page_counter.h>
58 #include <linux/memcontrol.h>
59 #include <linux/static_key.h>
60 #include <linux/sched.h>
61 #include <linux/wait.h>
62 #include <linux/cgroup-defs.h>
63 
64 #include <linux/filter.h>
65 #include <linux/rculist_nulls.h>
66 #include <linux/poll.h>
67 
68 #include <linux/atomic.h>
69 #include <linux/refcount.h>
70 #include <net/dst.h>
71 #include <net/checksum.h>
72 #include <net/tcp_states.h>
73 #include <linux/net_tstamp.h>
74 #include <net/smc.h>
75 
76 /*
77  * This structure really needs to be cleaned up.
78  * Most of it is for TCP, and not used by any of
79  * the other protocols.
80  */
81 
82 /* Define this to get the SOCK_DBG debugging facility. */
83 #define SOCK_DEBUGGING
84 #ifdef SOCK_DEBUGGING
85 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
86 					printk(KERN_DEBUG msg); } while (0)
87 #else
88 /* Validate arguments and do nothing */
89 static inline __printf(2, 3)
90 void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
91 {
92 }
93 #endif
94 
95 /* This is the per-socket lock.  The spinlock provides a synchronization
96  * between user contexts and software interrupt processing, whereas the
97  * mini-semaphore synchronizes multiple users amongst themselves.
98  */
99 typedef struct {
100 	spinlock_t		slock;
101 	int			owned;
102 	wait_queue_head_t	wq;
103 	/*
104 	 * We express the mutex-alike socket_lock semantics
105 	 * to the lock validator by explicitly managing
106 	 * the slock as a lock variant (in addition to
107 	 * the slock itself):
108 	 */
109 #ifdef CONFIG_DEBUG_LOCK_ALLOC
110 	struct lockdep_map dep_map;
111 #endif
112 } socket_lock_t;
113 
114 struct sock;
115 struct proto;
116 struct net;
117 
118 typedef __u32 __bitwise __portpair;
119 typedef __u64 __bitwise __addrpair;
120 
121 /**
122  *	struct sock_common - minimal network layer representation of sockets
123  *	@skc_daddr: Foreign IPv4 addr
124  *	@skc_rcv_saddr: Bound local IPv4 addr
125  *	@skc_hash: hash value used with various protocol lookup tables
126  *	@skc_u16hashes: two u16 hash values used by UDP lookup tables
127  *	@skc_dport: placeholder for inet_dport/tw_dport
128  *	@skc_num: placeholder for inet_num/tw_num
129  *	@skc_family: network address family
130  *	@skc_state: Connection state
131  *	@skc_reuse: %SO_REUSEADDR setting
132  *	@skc_reuseport: %SO_REUSEPORT setting
133  *	@skc_bound_dev_if: bound device index if != 0
134  *	@skc_bind_node: bind hash linkage for various protocol lookup tables
135  *	@skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
136  *	@skc_prot: protocol handlers inside a network family
137  *	@skc_net: reference to the network namespace of this socket
138  *	@skc_node: main hash linkage for various protocol lookup tables
139  *	@skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
140  *	@skc_tx_queue_mapping: tx queue number for this connection
141  *	@skc_flags: place holder for sk_flags
142  *		%SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
143  *		%SO_OOBINLINE settings, %SO_TIMESTAMPING settings
144  *	@skc_incoming_cpu: record/match cpu processing incoming packets
145  *	@skc_refcnt: reference count
146  *
147  *	This is the minimal network layer representation of sockets, the header
148  *	for struct sock and struct inet_timewait_sock.
149  */
150 struct sock_common {
151 	/* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned
152 	 * address on 64bit arches : cf INET_MATCH()
153 	 */
154 	union {
155 		__addrpair	skc_addrpair;
156 		struct {
157 			__be32	skc_daddr;
158 			__be32	skc_rcv_saddr;
159 		};
160 	};
161 	union  {
162 		unsigned int	skc_hash;
163 		__u16		skc_u16hashes[2];
164 	};
165 	/* skc_dport && skc_num must be grouped as well */
166 	union {
167 		__portpair	skc_portpair;
168 		struct {
169 			__be16	skc_dport;
170 			__u16	skc_num;
171 		};
172 	};
173 
174 	unsigned short		skc_family;
175 	volatile unsigned char	skc_state;
176 	unsigned char		skc_reuse:4;
177 	unsigned char		skc_reuseport:1;
178 	unsigned char		skc_ipv6only:1;
179 	unsigned char		skc_net_refcnt:1;
180 	int			skc_bound_dev_if;
181 	union {
182 		struct hlist_node	skc_bind_node;
183 		struct hlist_node	skc_portaddr_node;
184 	};
185 	struct proto		*skc_prot;
186 	possible_net_t		skc_net;
187 
188 #if IS_ENABLED(CONFIG_IPV6)
189 	struct in6_addr		skc_v6_daddr;
190 	struct in6_addr		skc_v6_rcv_saddr;
191 #endif
192 
193 	atomic64_t		skc_cookie;
194 
195 	/* following fields are padding to force
196 	 * offset(struct sock, sk_refcnt) == 128 on 64bit arches
197 	 * assuming IPV6 is enabled. We use this padding differently
198 	 * for different kind of 'sockets'
199 	 */
200 	union {
201 		unsigned long	skc_flags;
202 		struct sock	*skc_listener; /* request_sock */
203 		struct inet_timewait_death_row *skc_tw_dr; /* inet_timewait_sock */
204 	};
205 	/*
206 	 * fields between dontcopy_begin/dontcopy_end
207 	 * are not copied in sock_copy()
208 	 */
209 	/* private: */
210 	int			skc_dontcopy_begin[0];
211 	/* public: */
212 	union {
213 		struct hlist_node	skc_node;
214 		struct hlist_nulls_node skc_nulls_node;
215 	};
216 	int			skc_tx_queue_mapping;
217 	union {
218 		int		skc_incoming_cpu;
219 		u32		skc_rcv_wnd;
220 		u32		skc_tw_rcv_nxt; /* struct tcp_timewait_sock  */
221 	};
222 
223 	refcount_t		skc_refcnt;
224 	/* private: */
225 	int                     skc_dontcopy_end[0];
226 	union {
227 		u32		skc_rxhash;
228 		u32		skc_window_clamp;
229 		u32		skc_tw_snd_nxt; /* struct tcp_timewait_sock */
230 	};
231 	/* public: */
232 };
233 
234 /**
235   *	struct sock - network layer representation of sockets
236   *	@__sk_common: shared layout with inet_timewait_sock
237   *	@sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
238   *	@sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
239   *	@sk_lock:	synchronizer
240   *	@sk_kern_sock: True if sock is using kernel lock classes
241   *	@sk_rcvbuf: size of receive buffer in bytes
242   *	@sk_wq: sock wait queue and async head
243   *	@sk_rx_dst: receive input route used by early demux
244   *	@sk_dst_cache: destination cache
245   *	@sk_dst_pending_confirm: need to confirm neighbour
246   *	@sk_policy: flow policy
247   *	@sk_receive_queue: incoming packets
248   *	@sk_wmem_alloc: transmit queue bytes committed
249   *	@sk_tsq_flags: TCP Small Queues flags
250   *	@sk_write_queue: Packet sending queue
251   *	@sk_omem_alloc: "o" is "option" or "other"
252   *	@sk_wmem_queued: persistent queue size
253   *	@sk_forward_alloc: space allocated forward
254   *	@sk_napi_id: id of the last napi context to receive data for sk
255   *	@sk_ll_usec: usecs to busypoll when there is no data
256   *	@sk_allocation: allocation mode
257   *	@sk_pacing_rate: Pacing rate (if supported by transport/packet scheduler)
258   *	@sk_pacing_status: Pacing status (requested, handled by sch_fq)
259   *	@sk_max_pacing_rate: Maximum pacing rate (%SO_MAX_PACING_RATE)
260   *	@sk_sndbuf: size of send buffer in bytes
261   *	@__sk_flags_offset: empty field used to determine location of bitfield
262   *	@sk_padding: unused element for alignment
263   *	@sk_no_check_tx: %SO_NO_CHECK setting, set checksum in TX packets
264   *	@sk_no_check_rx: allow zero checksum in RX packets
265   *	@sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
266   *	@sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
267   *	@sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
268   *	@sk_gso_max_size: Maximum GSO segment size to build
269   *	@sk_gso_max_segs: Maximum number of GSO segments
270   *	@sk_lingertime: %SO_LINGER l_linger setting
271   *	@sk_backlog: always used with the per-socket spinlock held
272   *	@sk_callback_lock: used with the callbacks in the end of this struct
273   *	@sk_error_queue: rarely used
274   *	@sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
275   *			  IPV6_ADDRFORM for instance)
276   *	@sk_err: last error
277   *	@sk_err_soft: errors that don't cause failure but are the cause of a
278   *		      persistent failure not just 'timed out'
279   *	@sk_drops: raw/udp drops counter
280   *	@sk_ack_backlog: current listen backlog
281   *	@sk_max_ack_backlog: listen backlog set in listen()
282   *	@sk_uid: user id of owner
283   *	@sk_priority: %SO_PRIORITY setting
284   *	@sk_type: socket type (%SOCK_STREAM, etc)
285   *	@sk_protocol: which protocol this socket belongs in this network family
286   *	@sk_peer_pid: &struct pid for this socket's peer
287   *	@sk_peer_cred: %SO_PEERCRED setting
288   *	@sk_rcvlowat: %SO_RCVLOWAT setting
289   *	@sk_rcvtimeo: %SO_RCVTIMEO setting
290   *	@sk_sndtimeo: %SO_SNDTIMEO setting
291   *	@sk_txhash: computed flow hash for use on transmit
292   *	@sk_filter: socket filtering instructions
293   *	@sk_timer: sock cleanup timer
294   *	@sk_stamp: time stamp of last packet received
295   *	@sk_tsflags: SO_TIMESTAMPING socket options
296   *	@sk_tskey: counter to disambiguate concurrent tstamp requests
297   *	@sk_zckey: counter to order MSG_ZEROCOPY notifications
298   *	@sk_socket: Identd and reporting IO signals
299   *	@sk_user_data: RPC layer private data
300   *	@sk_frag: cached page frag
301   *	@sk_peek_off: current peek_offset value
302   *	@sk_send_head: front of stuff to transmit
303   *	@sk_security: used by security modules
304   *	@sk_mark: generic packet mark
305   *	@sk_cgrp_data: cgroup data for this cgroup
306   *	@sk_memcg: this socket's memory cgroup association
307   *	@sk_write_pending: a write to stream socket waits to start
308   *	@sk_state_change: callback to indicate change in the state of the sock
309   *	@sk_data_ready: callback to indicate there is data to be processed
310   *	@sk_write_space: callback to indicate there is bf sending space available
311   *	@sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
312   *	@sk_backlog_rcv: callback to process the backlog
313   *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
314   *	@sk_reuseport_cb: reuseport group container
315   *	@sk_rcu: used during RCU grace period
316   */
317 struct sock {
318 	/*
319 	 * Now struct inet_timewait_sock also uses sock_common, so please just
320 	 * don't add nothing before this first member (__sk_common) --acme
321 	 */
322 	struct sock_common	__sk_common;
323 #define sk_node			__sk_common.skc_node
324 #define sk_nulls_node		__sk_common.skc_nulls_node
325 #define sk_refcnt		__sk_common.skc_refcnt
326 #define sk_tx_queue_mapping	__sk_common.skc_tx_queue_mapping
327 
328 #define sk_dontcopy_begin	__sk_common.skc_dontcopy_begin
329 #define sk_dontcopy_end		__sk_common.skc_dontcopy_end
330 #define sk_hash			__sk_common.skc_hash
331 #define sk_portpair		__sk_common.skc_portpair
332 #define sk_num			__sk_common.skc_num
333 #define sk_dport		__sk_common.skc_dport
334 #define sk_addrpair		__sk_common.skc_addrpair
335 #define sk_daddr		__sk_common.skc_daddr
336 #define sk_rcv_saddr		__sk_common.skc_rcv_saddr
337 #define sk_family		__sk_common.skc_family
338 #define sk_state		__sk_common.skc_state
339 #define sk_reuse		__sk_common.skc_reuse
340 #define sk_reuseport		__sk_common.skc_reuseport
341 #define sk_ipv6only		__sk_common.skc_ipv6only
342 #define sk_net_refcnt		__sk_common.skc_net_refcnt
343 #define sk_bound_dev_if		__sk_common.skc_bound_dev_if
344 #define sk_bind_node		__sk_common.skc_bind_node
345 #define sk_prot			__sk_common.skc_prot
346 #define sk_net			__sk_common.skc_net
347 #define sk_v6_daddr		__sk_common.skc_v6_daddr
348 #define sk_v6_rcv_saddr	__sk_common.skc_v6_rcv_saddr
349 #define sk_cookie		__sk_common.skc_cookie
350 #define sk_incoming_cpu		__sk_common.skc_incoming_cpu
351 #define sk_flags		__sk_common.skc_flags
352 #define sk_rxhash		__sk_common.skc_rxhash
353 
354 	socket_lock_t		sk_lock;
355 	atomic_t		sk_drops;
356 	int			sk_rcvlowat;
357 	struct sk_buff_head	sk_error_queue;
358 	struct sk_buff_head	sk_receive_queue;
359 	/*
360 	 * The backlog queue is special, it is always used with
361 	 * the per-socket spinlock held and requires low latency
362 	 * access. Therefore we special case it's implementation.
363 	 * Note : rmem_alloc is in this structure to fill a hole
364 	 * on 64bit arches, not because its logically part of
365 	 * backlog.
366 	 */
367 	struct {
368 		atomic_t	rmem_alloc;
369 		int		len;
370 		struct sk_buff	*head;
371 		struct sk_buff	*tail;
372 	} sk_backlog;
373 #define sk_rmem_alloc sk_backlog.rmem_alloc
374 
375 	int			sk_forward_alloc;
376 #ifdef CONFIG_NET_RX_BUSY_POLL
377 	unsigned int		sk_ll_usec;
378 	/* ===== mostly read cache line ===== */
379 	unsigned int		sk_napi_id;
380 #endif
381 	int			sk_rcvbuf;
382 
383 	struct sk_filter __rcu	*sk_filter;
384 	union {
385 		struct socket_wq __rcu	*sk_wq;
386 		struct socket_wq	*sk_wq_raw;
387 	};
388 #ifdef CONFIG_XFRM
389 	struct xfrm_policy __rcu *sk_policy[2];
390 #endif
391 	struct dst_entry	*sk_rx_dst;
392 	struct dst_entry __rcu	*sk_dst_cache;
393 	atomic_t		sk_omem_alloc;
394 	int			sk_sndbuf;
395 
396 	/* ===== cache line for TX ===== */
397 	int			sk_wmem_queued;
398 	refcount_t		sk_wmem_alloc;
399 	unsigned long		sk_tsq_flags;
400 	struct sk_buff		*sk_send_head;
401 	struct sk_buff_head	sk_write_queue;
402 	__s32			sk_peek_off;
403 	int			sk_write_pending;
404 	__u32			sk_dst_pending_confirm;
405 	u32			sk_pacing_status; /* see enum sk_pacing */
406 	long			sk_sndtimeo;
407 	struct timer_list	sk_timer;
408 	__u32			sk_priority;
409 	__u32			sk_mark;
410 	u32			sk_pacing_rate; /* bytes per second */
411 	u32			sk_max_pacing_rate;
412 	struct page_frag	sk_frag;
413 	netdev_features_t	sk_route_caps;
414 	netdev_features_t	sk_route_nocaps;
415 	int			sk_gso_type;
416 	unsigned int		sk_gso_max_size;
417 	gfp_t			sk_allocation;
418 	__u32			sk_txhash;
419 
420 	/*
421 	 * Because of non atomicity rules, all
422 	 * changes are protected by socket lock.
423 	 */
424 	unsigned int		__sk_flags_offset[0];
425 #ifdef __BIG_ENDIAN_BITFIELD
426 #define SK_FL_PROTO_SHIFT  16
427 #define SK_FL_PROTO_MASK   0x00ff0000
428 
429 #define SK_FL_TYPE_SHIFT   0
430 #define SK_FL_TYPE_MASK    0x0000ffff
431 #else
432 #define SK_FL_PROTO_SHIFT  8
433 #define SK_FL_PROTO_MASK   0x0000ff00
434 
435 #define SK_FL_TYPE_SHIFT   16
436 #define SK_FL_TYPE_MASK    0xffff0000
437 #endif
438 
439 	kmemcheck_bitfield_begin(flags);
440 	unsigned int		sk_padding : 1,
441 				sk_kern_sock : 1,
442 				sk_no_check_tx : 1,
443 				sk_no_check_rx : 1,
444 				sk_userlocks : 4,
445 				sk_protocol  : 8,
446 				sk_type      : 16;
447 #define SK_PROTOCOL_MAX U8_MAX
448 	kmemcheck_bitfield_end(flags);
449 
450 	u16			sk_gso_max_segs;
451 	unsigned long	        sk_lingertime;
452 	struct proto		*sk_prot_creator;
453 	rwlock_t		sk_callback_lock;
454 	int			sk_err,
455 				sk_err_soft;
456 	u32			sk_ack_backlog;
457 	u32			sk_max_ack_backlog;
458 	kuid_t			sk_uid;
459 	struct pid		*sk_peer_pid;
460 	const struct cred	*sk_peer_cred;
461 	long			sk_rcvtimeo;
462 	ktime_t			sk_stamp;
463 	u16			sk_tsflags;
464 	u8			sk_shutdown;
465 	u32			sk_tskey;
466 	atomic_t		sk_zckey;
467 	struct socket		*sk_socket;
468 	void			*sk_user_data;
469 #ifdef CONFIG_SECURITY
470 	void			*sk_security;
471 #endif
472 	struct sock_cgroup_data	sk_cgrp_data;
473 	struct mem_cgroup	*sk_memcg;
474 	void			(*sk_state_change)(struct sock *sk);
475 	void			(*sk_data_ready)(struct sock *sk);
476 	void			(*sk_write_space)(struct sock *sk);
477 	void			(*sk_error_report)(struct sock *sk);
478 	int			(*sk_backlog_rcv)(struct sock *sk,
479 						  struct sk_buff *skb);
480 	void                    (*sk_destruct)(struct sock *sk);
481 	struct sock_reuseport __rcu	*sk_reuseport_cb;
482 	struct rcu_head		sk_rcu;
483 };
484 
485 enum sk_pacing {
486 	SK_PACING_NONE		= 0,
487 	SK_PACING_NEEDED	= 1,
488 	SK_PACING_FQ		= 2,
489 };
490 
491 #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data)))
492 
493 #define rcu_dereference_sk_user_data(sk)	rcu_dereference(__sk_user_data((sk)))
494 #define rcu_assign_sk_user_data(sk, ptr)	rcu_assign_pointer(__sk_user_data((sk)), ptr)
495 
496 /*
497  * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
498  * or not whether his port will be reused by someone else. SK_FORCE_REUSE
499  * on a socket means that the socket will reuse everybody else's port
500  * without looking at the other's sk_reuse value.
501  */
502 
503 #define SK_NO_REUSE	0
504 #define SK_CAN_REUSE	1
505 #define SK_FORCE_REUSE	2
506 
507 int sk_set_peek_off(struct sock *sk, int val);
508 
509 static inline int sk_peek_offset(struct sock *sk, int flags)
510 {
511 	if (unlikely(flags & MSG_PEEK)) {
512 		return READ_ONCE(sk->sk_peek_off);
513 	}
514 
515 	return 0;
516 }
517 
518 static inline void sk_peek_offset_bwd(struct sock *sk, int val)
519 {
520 	s32 off = READ_ONCE(sk->sk_peek_off);
521 
522 	if (unlikely(off >= 0)) {
523 		off = max_t(s32, off - val, 0);
524 		WRITE_ONCE(sk->sk_peek_off, off);
525 	}
526 }
527 
528 static inline void sk_peek_offset_fwd(struct sock *sk, int val)
529 {
530 	sk_peek_offset_bwd(sk, -val);
531 }
532 
533 /*
534  * Hashed lists helper routines
535  */
536 static inline struct sock *sk_entry(const struct hlist_node *node)
537 {
538 	return hlist_entry(node, struct sock, sk_node);
539 }
540 
541 static inline struct sock *__sk_head(const struct hlist_head *head)
542 {
543 	return hlist_entry(head->first, struct sock, sk_node);
544 }
545 
546 static inline struct sock *sk_head(const struct hlist_head *head)
547 {
548 	return hlist_empty(head) ? NULL : __sk_head(head);
549 }
550 
551 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
552 {
553 	return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
554 }
555 
556 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
557 {
558 	return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
559 }
560 
561 static inline struct sock *sk_next(const struct sock *sk)
562 {
563 	return hlist_entry_safe(sk->sk_node.next, struct sock, sk_node);
564 }
565 
566 static inline struct sock *sk_nulls_next(const struct sock *sk)
567 {
568 	return (!is_a_nulls(sk->sk_nulls_node.next)) ?
569 		hlist_nulls_entry(sk->sk_nulls_node.next,
570 				  struct sock, sk_nulls_node) :
571 		NULL;
572 }
573 
574 static inline bool sk_unhashed(const struct sock *sk)
575 {
576 	return hlist_unhashed(&sk->sk_node);
577 }
578 
579 static inline bool sk_hashed(const struct sock *sk)
580 {
581 	return !sk_unhashed(sk);
582 }
583 
584 static inline void sk_node_init(struct hlist_node *node)
585 {
586 	node->pprev = NULL;
587 }
588 
589 static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
590 {
591 	node->pprev = NULL;
592 }
593 
594 static inline void __sk_del_node(struct sock *sk)
595 {
596 	__hlist_del(&sk->sk_node);
597 }
598 
599 /* NB: equivalent to hlist_del_init_rcu */
600 static inline bool __sk_del_node_init(struct sock *sk)
601 {
602 	if (sk_hashed(sk)) {
603 		__sk_del_node(sk);
604 		sk_node_init(&sk->sk_node);
605 		return true;
606 	}
607 	return false;
608 }
609 
610 /* Grab socket reference count. This operation is valid only
611    when sk is ALREADY grabbed f.e. it is found in hash table
612    or a list and the lookup is made under lock preventing hash table
613    modifications.
614  */
615 
616 static __always_inline void sock_hold(struct sock *sk)
617 {
618 	refcount_inc(&sk->sk_refcnt);
619 }
620 
621 /* Ungrab socket in the context, which assumes that socket refcnt
622    cannot hit zero, f.e. it is true in context of any socketcall.
623  */
624 static __always_inline void __sock_put(struct sock *sk)
625 {
626 	refcount_dec(&sk->sk_refcnt);
627 }
628 
629 static inline bool sk_del_node_init(struct sock *sk)
630 {
631 	bool rc = __sk_del_node_init(sk);
632 
633 	if (rc) {
634 		/* paranoid for a while -acme */
635 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
636 		__sock_put(sk);
637 	}
638 	return rc;
639 }
640 #define sk_del_node_init_rcu(sk)	sk_del_node_init(sk)
641 
642 static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
643 {
644 	if (sk_hashed(sk)) {
645 		hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
646 		return true;
647 	}
648 	return false;
649 }
650 
651 static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
652 {
653 	bool rc = __sk_nulls_del_node_init_rcu(sk);
654 
655 	if (rc) {
656 		/* paranoid for a while -acme */
657 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
658 		__sock_put(sk);
659 	}
660 	return rc;
661 }
662 
663 static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
664 {
665 	hlist_add_head(&sk->sk_node, list);
666 }
667 
668 static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
669 {
670 	sock_hold(sk);
671 	__sk_add_node(sk, list);
672 }
673 
674 static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
675 {
676 	sock_hold(sk);
677 	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
678 	    sk->sk_family == AF_INET6)
679 		hlist_add_tail_rcu(&sk->sk_node, list);
680 	else
681 		hlist_add_head_rcu(&sk->sk_node, list);
682 }
683 
684 static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
685 {
686 	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
687 	    sk->sk_family == AF_INET6)
688 		hlist_nulls_add_tail_rcu(&sk->sk_nulls_node, list);
689 	else
690 		hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
691 }
692 
693 static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
694 {
695 	sock_hold(sk);
696 	__sk_nulls_add_node_rcu(sk, list);
697 }
698 
699 static inline void __sk_del_bind_node(struct sock *sk)
700 {
701 	__hlist_del(&sk->sk_bind_node);
702 }
703 
704 static inline void sk_add_bind_node(struct sock *sk,
705 					struct hlist_head *list)
706 {
707 	hlist_add_head(&sk->sk_bind_node, list);
708 }
709 
710 #define sk_for_each(__sk, list) \
711 	hlist_for_each_entry(__sk, list, sk_node)
712 #define sk_for_each_rcu(__sk, list) \
713 	hlist_for_each_entry_rcu(__sk, list, sk_node)
714 #define sk_nulls_for_each(__sk, node, list) \
715 	hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
716 #define sk_nulls_for_each_rcu(__sk, node, list) \
717 	hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
718 #define sk_for_each_from(__sk) \
719 	hlist_for_each_entry_from(__sk, sk_node)
720 #define sk_nulls_for_each_from(__sk, node) \
721 	if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
722 		hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
723 #define sk_for_each_safe(__sk, tmp, list) \
724 	hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
725 #define sk_for_each_bound(__sk, list) \
726 	hlist_for_each_entry(__sk, list, sk_bind_node)
727 
728 /**
729  * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset
730  * @tpos:	the type * to use as a loop cursor.
731  * @pos:	the &struct hlist_node to use as a loop cursor.
732  * @head:	the head for your list.
733  * @offset:	offset of hlist_node within the struct.
734  *
735  */
736 #define sk_for_each_entry_offset_rcu(tpos, pos, head, offset)		       \
737 	for (pos = rcu_dereference((head)->first);			       \
738 	     pos != NULL &&						       \
739 		({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \
740 	     pos = rcu_dereference(pos->next))
741 
742 static inline struct user_namespace *sk_user_ns(struct sock *sk)
743 {
744 	/* Careful only use this in a context where these parameters
745 	 * can not change and must all be valid, such as recvmsg from
746 	 * userspace.
747 	 */
748 	return sk->sk_socket->file->f_cred->user_ns;
749 }
750 
751 /* Sock flags */
752 enum sock_flags {
753 	SOCK_DEAD,
754 	SOCK_DONE,
755 	SOCK_URGINLINE,
756 	SOCK_KEEPOPEN,
757 	SOCK_LINGER,
758 	SOCK_DESTROY,
759 	SOCK_BROADCAST,
760 	SOCK_TIMESTAMP,
761 	SOCK_ZAPPED,
762 	SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
763 	SOCK_DBG, /* %SO_DEBUG setting */
764 	SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
765 	SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
766 	SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
767 	SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
768 	SOCK_MEMALLOC, /* VM depends on this socket for swapping */
769 	SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
770 	SOCK_FASYNC, /* fasync() active */
771 	SOCK_RXQ_OVFL,
772 	SOCK_ZEROCOPY, /* buffers from userspace */
773 	SOCK_WIFI_STATUS, /* push wifi status to userspace */
774 	SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
775 		     * Will use last 4 bytes of packet sent from
776 		     * user-space instead.
777 		     */
778 	SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
779 	SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
780 	SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
781 };
782 
783 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
784 
785 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
786 {
787 	nsk->sk_flags = osk->sk_flags;
788 }
789 
790 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
791 {
792 	__set_bit(flag, &sk->sk_flags);
793 }
794 
795 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
796 {
797 	__clear_bit(flag, &sk->sk_flags);
798 }
799 
800 static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
801 {
802 	return test_bit(flag, &sk->sk_flags);
803 }
804 
805 #ifdef CONFIG_NET
806 extern struct static_key memalloc_socks;
807 static inline int sk_memalloc_socks(void)
808 {
809 	return static_key_false(&memalloc_socks);
810 }
811 #else
812 
813 static inline int sk_memalloc_socks(void)
814 {
815 	return 0;
816 }
817 
818 #endif
819 
820 static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)
821 {
822 	return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);
823 }
824 
825 static inline void sk_acceptq_removed(struct sock *sk)
826 {
827 	sk->sk_ack_backlog--;
828 }
829 
830 static inline void sk_acceptq_added(struct sock *sk)
831 {
832 	sk->sk_ack_backlog++;
833 }
834 
835 static inline bool sk_acceptq_is_full(const struct sock *sk)
836 {
837 	return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
838 }
839 
840 /*
841  * Compute minimal free write space needed to queue new packets.
842  */
843 static inline int sk_stream_min_wspace(const struct sock *sk)
844 {
845 	return sk->sk_wmem_queued >> 1;
846 }
847 
848 static inline int sk_stream_wspace(const struct sock *sk)
849 {
850 	return sk->sk_sndbuf - sk->sk_wmem_queued;
851 }
852 
853 void sk_stream_write_space(struct sock *sk);
854 
855 /* OOB backlog add */
856 static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
857 {
858 	/* dont let skb dst not refcounted, we are going to leave rcu lock */
859 	skb_dst_force(skb);
860 
861 	if (!sk->sk_backlog.tail)
862 		sk->sk_backlog.head = skb;
863 	else
864 		sk->sk_backlog.tail->next = skb;
865 
866 	sk->sk_backlog.tail = skb;
867 	skb->next = NULL;
868 }
869 
870 /*
871  * Take into account size of receive queue and backlog queue
872  * Do not take into account this skb truesize,
873  * to allow even a single big packet to come.
874  */
875 static inline bool sk_rcvqueues_full(const struct sock *sk, unsigned int limit)
876 {
877 	unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
878 
879 	return qsize > limit;
880 }
881 
882 /* The per-socket spinlock must be held here. */
883 static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
884 					      unsigned int limit)
885 {
886 	if (sk_rcvqueues_full(sk, limit))
887 		return -ENOBUFS;
888 
889 	/*
890 	 * If the skb was allocated from pfmemalloc reserves, only
891 	 * allow SOCK_MEMALLOC sockets to use it as this socket is
892 	 * helping free memory
893 	 */
894 	if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
895 		return -ENOMEM;
896 
897 	__sk_add_backlog(sk, skb);
898 	sk->sk_backlog.len += skb->truesize;
899 	return 0;
900 }
901 
902 int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
903 
904 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
905 {
906 	if (sk_memalloc_socks() && skb_pfmemalloc(skb))
907 		return __sk_backlog_rcv(sk, skb);
908 
909 	return sk->sk_backlog_rcv(sk, skb);
910 }
911 
912 static inline void sk_incoming_cpu_update(struct sock *sk)
913 {
914 	int cpu = raw_smp_processor_id();
915 
916 	if (unlikely(sk->sk_incoming_cpu != cpu))
917 		sk->sk_incoming_cpu = cpu;
918 }
919 
920 static inline void sock_rps_record_flow_hash(__u32 hash)
921 {
922 #ifdef CONFIG_RPS
923 	struct rps_sock_flow_table *sock_flow_table;
924 
925 	rcu_read_lock();
926 	sock_flow_table = rcu_dereference(rps_sock_flow_table);
927 	rps_record_sock_flow(sock_flow_table, hash);
928 	rcu_read_unlock();
929 #endif
930 }
931 
932 static inline void sock_rps_record_flow(const struct sock *sk)
933 {
934 #ifdef CONFIG_RPS
935 	if (static_key_false(&rfs_needed)) {
936 		/* Reading sk->sk_rxhash might incur an expensive cache line
937 		 * miss.
938 		 *
939 		 * TCP_ESTABLISHED does cover almost all states where RFS
940 		 * might be useful, and is cheaper [1] than testing :
941 		 *	IPv4: inet_sk(sk)->inet_daddr
942 		 * 	IPv6: ipv6_addr_any(&sk->sk_v6_daddr)
943 		 * OR	an additional socket flag
944 		 * [1] : sk_state and sk_prot are in the same cache line.
945 		 */
946 		if (sk->sk_state == TCP_ESTABLISHED)
947 			sock_rps_record_flow_hash(sk->sk_rxhash);
948 	}
949 #endif
950 }
951 
952 static inline void sock_rps_save_rxhash(struct sock *sk,
953 					const struct sk_buff *skb)
954 {
955 #ifdef CONFIG_RPS
956 	if (unlikely(sk->sk_rxhash != skb->hash))
957 		sk->sk_rxhash = skb->hash;
958 #endif
959 }
960 
961 static inline void sock_rps_reset_rxhash(struct sock *sk)
962 {
963 #ifdef CONFIG_RPS
964 	sk->sk_rxhash = 0;
965 #endif
966 }
967 
968 #define sk_wait_event(__sk, __timeo, __condition, __wait)		\
969 	({	int __rc;						\
970 		release_sock(__sk);					\
971 		__rc = __condition;					\
972 		if (!__rc) {						\
973 			*(__timeo) = wait_woken(__wait,			\
974 						TASK_INTERRUPTIBLE,	\
975 						*(__timeo));		\
976 		}							\
977 		sched_annotate_sleep();					\
978 		lock_sock(__sk);					\
979 		__rc = __condition;					\
980 		__rc;							\
981 	})
982 
983 int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
984 int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
985 void sk_stream_wait_close(struct sock *sk, long timeo_p);
986 int sk_stream_error(struct sock *sk, int flags, int err);
987 void sk_stream_kill_queues(struct sock *sk);
988 void sk_set_memalloc(struct sock *sk);
989 void sk_clear_memalloc(struct sock *sk);
990 
991 void __sk_flush_backlog(struct sock *sk);
992 
993 static inline bool sk_flush_backlog(struct sock *sk)
994 {
995 	if (unlikely(READ_ONCE(sk->sk_backlog.tail))) {
996 		__sk_flush_backlog(sk);
997 		return true;
998 	}
999 	return false;
1000 }
1001 
1002 int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb);
1003 
1004 struct request_sock_ops;
1005 struct timewait_sock_ops;
1006 struct inet_hashinfo;
1007 struct raw_hashinfo;
1008 struct smc_hashinfo;
1009 struct module;
1010 
1011 /*
1012  * caches using SLAB_TYPESAFE_BY_RCU should let .next pointer from nulls nodes
1013  * un-modified. Special care is taken when initializing object to zero.
1014  */
1015 static inline void sk_prot_clear_nulls(struct sock *sk, int size)
1016 {
1017 	if (offsetof(struct sock, sk_node.next) != 0)
1018 		memset(sk, 0, offsetof(struct sock, sk_node.next));
1019 	memset(&sk->sk_node.pprev, 0,
1020 	       size - offsetof(struct sock, sk_node.pprev));
1021 }
1022 
1023 /* Networking protocol blocks we attach to sockets.
1024  * socket layer -> transport layer interface
1025  */
1026 struct proto {
1027 	void			(*close)(struct sock *sk,
1028 					long timeout);
1029 	int			(*connect)(struct sock *sk,
1030 					struct sockaddr *uaddr,
1031 					int addr_len);
1032 	int			(*disconnect)(struct sock *sk, int flags);
1033 
1034 	struct sock *		(*accept)(struct sock *sk, int flags, int *err,
1035 					  bool kern);
1036 
1037 	int			(*ioctl)(struct sock *sk, int cmd,
1038 					 unsigned long arg);
1039 	int			(*init)(struct sock *sk);
1040 	void			(*destroy)(struct sock *sk);
1041 	void			(*shutdown)(struct sock *sk, int how);
1042 	int			(*setsockopt)(struct sock *sk, int level,
1043 					int optname, char __user *optval,
1044 					unsigned int optlen);
1045 	int			(*getsockopt)(struct sock *sk, int level,
1046 					int optname, char __user *optval,
1047 					int __user *option);
1048 	void			(*keepalive)(struct sock *sk, int valbool);
1049 #ifdef CONFIG_COMPAT
1050 	int			(*compat_setsockopt)(struct sock *sk,
1051 					int level,
1052 					int optname, char __user *optval,
1053 					unsigned int optlen);
1054 	int			(*compat_getsockopt)(struct sock *sk,
1055 					int level,
1056 					int optname, char __user *optval,
1057 					int __user *option);
1058 	int			(*compat_ioctl)(struct sock *sk,
1059 					unsigned int cmd, unsigned long arg);
1060 #endif
1061 	int			(*sendmsg)(struct sock *sk, struct msghdr *msg,
1062 					   size_t len);
1063 	int			(*recvmsg)(struct sock *sk, struct msghdr *msg,
1064 					   size_t len, int noblock, int flags,
1065 					   int *addr_len);
1066 	int			(*sendpage)(struct sock *sk, struct page *page,
1067 					int offset, size_t size, int flags);
1068 	int			(*bind)(struct sock *sk,
1069 					struct sockaddr *uaddr, int addr_len);
1070 
1071 	int			(*backlog_rcv) (struct sock *sk,
1072 						struct sk_buff *skb);
1073 
1074 	void		(*release_cb)(struct sock *sk);
1075 
1076 	/* Keeping track of sk's, looking them up, and port selection methods. */
1077 	int			(*hash)(struct sock *sk);
1078 	void			(*unhash)(struct sock *sk);
1079 	void			(*rehash)(struct sock *sk);
1080 	int			(*get_port)(struct sock *sk, unsigned short snum);
1081 
1082 	/* Keeping track of sockets in use */
1083 #ifdef CONFIG_PROC_FS
1084 	unsigned int		inuse_idx;
1085 #endif
1086 
1087 	bool			(*stream_memory_free)(const struct sock *sk);
1088 	/* Memory pressure */
1089 	void			(*enter_memory_pressure)(struct sock *sk);
1090 	void			(*leave_memory_pressure)(struct sock *sk);
1091 	atomic_long_t		*memory_allocated;	/* Current allocated memory. */
1092 	struct percpu_counter	*sockets_allocated;	/* Current number of sockets. */
1093 	/*
1094 	 * Pressure flag: try to collapse.
1095 	 * Technical note: it is used by multiple contexts non atomically.
1096 	 * All the __sk_mem_schedule() is of this nature: accounting
1097 	 * is strict, actions are advisory and have some latency.
1098 	 */
1099 	unsigned long		*memory_pressure;
1100 	long			*sysctl_mem;
1101 	int			*sysctl_wmem;
1102 	int			*sysctl_rmem;
1103 	int			max_header;
1104 	bool			no_autobind;
1105 
1106 	struct kmem_cache	*slab;
1107 	unsigned int		obj_size;
1108 	int			slab_flags;
1109 
1110 	struct percpu_counter	*orphan_count;
1111 
1112 	struct request_sock_ops	*rsk_prot;
1113 	struct timewait_sock_ops *twsk_prot;
1114 
1115 	union {
1116 		struct inet_hashinfo	*hashinfo;
1117 		struct udp_table	*udp_table;
1118 		struct raw_hashinfo	*raw_hash;
1119 		struct smc_hashinfo	*smc_hash;
1120 	} h;
1121 
1122 	struct module		*owner;
1123 
1124 	char			name[32];
1125 
1126 	struct list_head	node;
1127 #ifdef SOCK_REFCNT_DEBUG
1128 	atomic_t		socks;
1129 #endif
1130 	int			(*diag_destroy)(struct sock *sk, int err);
1131 } __randomize_layout;
1132 
1133 int proto_register(struct proto *prot, int alloc_slab);
1134 void proto_unregister(struct proto *prot);
1135 
1136 #ifdef SOCK_REFCNT_DEBUG
1137 static inline void sk_refcnt_debug_inc(struct sock *sk)
1138 {
1139 	atomic_inc(&sk->sk_prot->socks);
1140 }
1141 
1142 static inline void sk_refcnt_debug_dec(struct sock *sk)
1143 {
1144 	atomic_dec(&sk->sk_prot->socks);
1145 	printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1146 	       sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1147 }
1148 
1149 static inline void sk_refcnt_debug_release(const struct sock *sk)
1150 {
1151 	if (refcount_read(&sk->sk_refcnt) != 1)
1152 		printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1153 		       sk->sk_prot->name, sk, refcount_read(&sk->sk_refcnt));
1154 }
1155 #else /* SOCK_REFCNT_DEBUG */
1156 #define sk_refcnt_debug_inc(sk) do { } while (0)
1157 #define sk_refcnt_debug_dec(sk) do { } while (0)
1158 #define sk_refcnt_debug_release(sk) do { } while (0)
1159 #endif /* SOCK_REFCNT_DEBUG */
1160 
1161 static inline bool sk_stream_memory_free(const struct sock *sk)
1162 {
1163 	if (sk->sk_wmem_queued >= sk->sk_sndbuf)
1164 		return false;
1165 
1166 	return sk->sk_prot->stream_memory_free ?
1167 		sk->sk_prot->stream_memory_free(sk) : true;
1168 }
1169 
1170 static inline bool sk_stream_is_writeable(const struct sock *sk)
1171 {
1172 	return sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) &&
1173 	       sk_stream_memory_free(sk);
1174 }
1175 
1176 static inline int sk_under_cgroup_hierarchy(struct sock *sk,
1177 					    struct cgroup *ancestor)
1178 {
1179 #ifdef CONFIG_SOCK_CGROUP_DATA
1180 	return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data),
1181 				    ancestor);
1182 #else
1183 	return -ENOTSUPP;
1184 #endif
1185 }
1186 
1187 static inline bool sk_has_memory_pressure(const struct sock *sk)
1188 {
1189 	return sk->sk_prot->memory_pressure != NULL;
1190 }
1191 
1192 static inline bool sk_under_memory_pressure(const struct sock *sk)
1193 {
1194 	if (!sk->sk_prot->memory_pressure)
1195 		return false;
1196 
1197 	if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
1198 	    mem_cgroup_under_socket_pressure(sk->sk_memcg))
1199 		return true;
1200 
1201 	return !!*sk->sk_prot->memory_pressure;
1202 }
1203 
1204 static inline long
1205 sk_memory_allocated(const struct sock *sk)
1206 {
1207 	return atomic_long_read(sk->sk_prot->memory_allocated);
1208 }
1209 
1210 static inline long
1211 sk_memory_allocated_add(struct sock *sk, int amt)
1212 {
1213 	return atomic_long_add_return(amt, sk->sk_prot->memory_allocated);
1214 }
1215 
1216 static inline void
1217 sk_memory_allocated_sub(struct sock *sk, int amt)
1218 {
1219 	atomic_long_sub(amt, sk->sk_prot->memory_allocated);
1220 }
1221 
1222 static inline void sk_sockets_allocated_dec(struct sock *sk)
1223 {
1224 	percpu_counter_dec(sk->sk_prot->sockets_allocated);
1225 }
1226 
1227 static inline void sk_sockets_allocated_inc(struct sock *sk)
1228 {
1229 	percpu_counter_inc(sk->sk_prot->sockets_allocated);
1230 }
1231 
1232 static inline int
1233 sk_sockets_allocated_read_positive(struct sock *sk)
1234 {
1235 	return percpu_counter_read_positive(sk->sk_prot->sockets_allocated);
1236 }
1237 
1238 static inline int
1239 proto_sockets_allocated_sum_positive(struct proto *prot)
1240 {
1241 	return percpu_counter_sum_positive(prot->sockets_allocated);
1242 }
1243 
1244 static inline long
1245 proto_memory_allocated(struct proto *prot)
1246 {
1247 	return atomic_long_read(prot->memory_allocated);
1248 }
1249 
1250 static inline bool
1251 proto_memory_pressure(struct proto *prot)
1252 {
1253 	if (!prot->memory_pressure)
1254 		return false;
1255 	return !!*prot->memory_pressure;
1256 }
1257 
1258 
1259 #ifdef CONFIG_PROC_FS
1260 /* Called with local bh disabled */
1261 void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1262 int sock_prot_inuse_get(struct net *net, struct proto *proto);
1263 #else
1264 static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1265 		int inc)
1266 {
1267 }
1268 #endif
1269 
1270 
1271 /* With per-bucket locks this operation is not-atomic, so that
1272  * this version is not worse.
1273  */
1274 static inline int __sk_prot_rehash(struct sock *sk)
1275 {
1276 	sk->sk_prot->unhash(sk);
1277 	return sk->sk_prot->hash(sk);
1278 }
1279 
1280 /* About 10 seconds */
1281 #define SOCK_DESTROY_TIME (10*HZ)
1282 
1283 /* Sockets 0-1023 can't be bound to unless you are superuser */
1284 #define PROT_SOCK	1024
1285 
1286 #define SHUTDOWN_MASK	3
1287 #define RCV_SHUTDOWN	1
1288 #define SEND_SHUTDOWN	2
1289 
1290 #define SOCK_SNDBUF_LOCK	1
1291 #define SOCK_RCVBUF_LOCK	2
1292 #define SOCK_BINDADDR_LOCK	4
1293 #define SOCK_BINDPORT_LOCK	8
1294 
1295 struct socket_alloc {
1296 	struct socket socket;
1297 	struct inode vfs_inode;
1298 };
1299 
1300 static inline struct socket *SOCKET_I(struct inode *inode)
1301 {
1302 	return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1303 }
1304 
1305 static inline struct inode *SOCK_INODE(struct socket *socket)
1306 {
1307 	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1308 }
1309 
1310 /*
1311  * Functions for memory accounting
1312  */
1313 int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind);
1314 int __sk_mem_schedule(struct sock *sk, int size, int kind);
1315 void __sk_mem_reduce_allocated(struct sock *sk, int amount);
1316 void __sk_mem_reclaim(struct sock *sk, int amount);
1317 
1318 /* We used to have PAGE_SIZE here, but systems with 64KB pages
1319  * do not necessarily have 16x time more memory than 4KB ones.
1320  */
1321 #define SK_MEM_QUANTUM 4096
1322 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1323 #define SK_MEM_SEND	0
1324 #define SK_MEM_RECV	1
1325 
1326 /* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
1327 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1328 {
1329 	long val = sk->sk_prot->sysctl_mem[index];
1330 
1331 #if PAGE_SIZE > SK_MEM_QUANTUM
1332 	val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
1333 #elif PAGE_SIZE < SK_MEM_QUANTUM
1334 	val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
1335 #endif
1336 	return val;
1337 }
1338 
1339 static inline int sk_mem_pages(int amt)
1340 {
1341 	return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1342 }
1343 
1344 static inline bool sk_has_account(struct sock *sk)
1345 {
1346 	/* return true if protocol supports memory accounting */
1347 	return !!sk->sk_prot->memory_allocated;
1348 }
1349 
1350 static inline bool sk_wmem_schedule(struct sock *sk, int size)
1351 {
1352 	if (!sk_has_account(sk))
1353 		return true;
1354 	return size <= sk->sk_forward_alloc ||
1355 		__sk_mem_schedule(sk, size, SK_MEM_SEND);
1356 }
1357 
1358 static inline bool
1359 sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1360 {
1361 	if (!sk_has_account(sk))
1362 		return true;
1363 	return size<= sk->sk_forward_alloc ||
1364 		__sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1365 		skb_pfmemalloc(skb);
1366 }
1367 
1368 static inline void sk_mem_reclaim(struct sock *sk)
1369 {
1370 	if (!sk_has_account(sk))
1371 		return;
1372 	if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1373 		__sk_mem_reclaim(sk, sk->sk_forward_alloc);
1374 }
1375 
1376 static inline void sk_mem_reclaim_partial(struct sock *sk)
1377 {
1378 	if (!sk_has_account(sk))
1379 		return;
1380 	if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1381 		__sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);
1382 }
1383 
1384 static inline void sk_mem_charge(struct sock *sk, int size)
1385 {
1386 	if (!sk_has_account(sk))
1387 		return;
1388 	sk->sk_forward_alloc -= size;
1389 }
1390 
1391 static inline void sk_mem_uncharge(struct sock *sk, int size)
1392 {
1393 	if (!sk_has_account(sk))
1394 		return;
1395 	sk->sk_forward_alloc += size;
1396 
1397 	/* Avoid a possible overflow.
1398 	 * TCP send queues can make this happen, if sk_mem_reclaim()
1399 	 * is not called and more than 2 GBytes are released at once.
1400 	 *
1401 	 * If we reach 2 MBytes, reclaim 1 MBytes right now, there is
1402 	 * no need to hold that much forward allocation anyway.
1403 	 */
1404 	if (unlikely(sk->sk_forward_alloc >= 1 << 21))
1405 		__sk_mem_reclaim(sk, 1 << 20);
1406 }
1407 
1408 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1409 {
1410 	sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
1411 	sk->sk_wmem_queued -= skb->truesize;
1412 	sk_mem_uncharge(sk, skb->truesize);
1413 	__kfree_skb(skb);
1414 }
1415 
1416 static inline void sock_release_ownership(struct sock *sk)
1417 {
1418 	if (sk->sk_lock.owned) {
1419 		sk->sk_lock.owned = 0;
1420 
1421 		/* The sk_lock has mutex_unlock() semantics: */
1422 		mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
1423 	}
1424 }
1425 
1426 /*
1427  * Macro so as to not evaluate some arguments when
1428  * lockdep is not enabled.
1429  *
1430  * Mark both the sk_lock and the sk_lock.slock as a
1431  * per-address-family lock class.
1432  */
1433 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)	\
1434 do {									\
1435 	sk->sk_lock.owned = 0;						\
1436 	init_waitqueue_head(&sk->sk_lock.wq);				\
1437 	spin_lock_init(&(sk)->sk_lock.slock);				\
1438 	debug_check_no_locks_freed((void *)&(sk)->sk_lock,		\
1439 			sizeof((sk)->sk_lock));				\
1440 	lockdep_set_class_and_name(&(sk)->sk_lock.slock,		\
1441 				(skey), (sname));				\
1442 	lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);	\
1443 } while (0)
1444 
1445 #ifdef CONFIG_LOCKDEP
1446 static inline bool lockdep_sock_is_held(const struct sock *csk)
1447 {
1448 	struct sock *sk = (struct sock *)csk;
1449 
1450 	return lockdep_is_held(&sk->sk_lock) ||
1451 	       lockdep_is_held(&sk->sk_lock.slock);
1452 }
1453 #endif
1454 
1455 void lock_sock_nested(struct sock *sk, int subclass);
1456 
1457 static inline void lock_sock(struct sock *sk)
1458 {
1459 	lock_sock_nested(sk, 0);
1460 }
1461 
1462 void release_sock(struct sock *sk);
1463 
1464 /* BH context may only use the following locking interface. */
1465 #define bh_lock_sock(__sk)	spin_lock(&((__sk)->sk_lock.slock))
1466 #define bh_lock_sock_nested(__sk) \
1467 				spin_lock_nested(&((__sk)->sk_lock.slock), \
1468 				SINGLE_DEPTH_NESTING)
1469 #define bh_unlock_sock(__sk)	spin_unlock(&((__sk)->sk_lock.slock))
1470 
1471 bool lock_sock_fast(struct sock *sk);
1472 /**
1473  * unlock_sock_fast - complement of lock_sock_fast
1474  * @sk: socket
1475  * @slow: slow mode
1476  *
1477  * fast unlock socket for user context.
1478  * If slow mode is on, we call regular release_sock()
1479  */
1480 static inline void unlock_sock_fast(struct sock *sk, bool slow)
1481 {
1482 	if (slow)
1483 		release_sock(sk);
1484 	else
1485 		spin_unlock_bh(&sk->sk_lock.slock);
1486 }
1487 
1488 /* Used by processes to "lock" a socket state, so that
1489  * interrupts and bottom half handlers won't change it
1490  * from under us. It essentially blocks any incoming
1491  * packets, so that we won't get any new data or any
1492  * packets that change the state of the socket.
1493  *
1494  * While locked, BH processing will add new packets to
1495  * the backlog queue.  This queue is processed by the
1496  * owner of the socket lock right before it is released.
1497  *
1498  * Since ~2.3.5 it is also exclusive sleep lock serializing
1499  * accesses from user process context.
1500  */
1501 
1502 static inline void sock_owned_by_me(const struct sock *sk)
1503 {
1504 #ifdef CONFIG_LOCKDEP
1505 	WARN_ON_ONCE(!lockdep_sock_is_held(sk) && debug_locks);
1506 #endif
1507 }
1508 
1509 static inline bool sock_owned_by_user(const struct sock *sk)
1510 {
1511 	sock_owned_by_me(sk);
1512 	return sk->sk_lock.owned;
1513 }
1514 
1515 /* no reclassification while locks are held */
1516 static inline bool sock_allow_reclassification(const struct sock *csk)
1517 {
1518 	struct sock *sk = (struct sock *)csk;
1519 
1520 	return !sk->sk_lock.owned && !spin_is_locked(&sk->sk_lock.slock);
1521 }
1522 
1523 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
1524 		      struct proto *prot, int kern);
1525 void sk_free(struct sock *sk);
1526 void sk_destruct(struct sock *sk);
1527 struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority);
1528 void sk_free_unlock_clone(struct sock *sk);
1529 
1530 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
1531 			     gfp_t priority);
1532 void __sock_wfree(struct sk_buff *skb);
1533 void sock_wfree(struct sk_buff *skb);
1534 struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size,
1535 			     gfp_t priority);
1536 void skb_orphan_partial(struct sk_buff *skb);
1537 void sock_rfree(struct sk_buff *skb);
1538 void sock_efree(struct sk_buff *skb);
1539 #ifdef CONFIG_INET
1540 void sock_edemux(struct sk_buff *skb);
1541 #else
1542 #define sock_edemux sock_efree
1543 #endif
1544 
1545 int sock_setsockopt(struct socket *sock, int level, int op,
1546 		    char __user *optval, unsigned int optlen);
1547 
1548 int sock_getsockopt(struct socket *sock, int level, int op,
1549 		    char __user *optval, int __user *optlen);
1550 struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
1551 				    int noblock, int *errcode);
1552 struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
1553 				     unsigned long data_len, int noblock,
1554 				     int *errcode, int max_page_order);
1555 void *sock_kmalloc(struct sock *sk, int size, gfp_t priority);
1556 void sock_kfree_s(struct sock *sk, void *mem, int size);
1557 void sock_kzfree_s(struct sock *sk, void *mem, int size);
1558 void sk_send_sigurg(struct sock *sk);
1559 
1560 struct sockcm_cookie {
1561 	u32 mark;
1562 	u16 tsflags;
1563 };
1564 
1565 int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
1566 		     struct sockcm_cookie *sockc);
1567 int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
1568 		   struct sockcm_cookie *sockc);
1569 
1570 /*
1571  * Functions to fill in entries in struct proto_ops when a protocol
1572  * does not implement a particular function.
1573  */
1574 int sock_no_bind(struct socket *, struct sockaddr *, int);
1575 int sock_no_connect(struct socket *, struct sockaddr *, int, int);
1576 int sock_no_socketpair(struct socket *, struct socket *);
1577 int sock_no_accept(struct socket *, struct socket *, int, bool);
1578 int sock_no_getname(struct socket *, struct sockaddr *, int *, int);
1579 unsigned int sock_no_poll(struct file *, struct socket *,
1580 			  struct poll_table_struct *);
1581 int sock_no_ioctl(struct socket *, unsigned int, unsigned long);
1582 int sock_no_listen(struct socket *, int);
1583 int sock_no_shutdown(struct socket *, int);
1584 int sock_no_getsockopt(struct socket *, int , int, char __user *, int __user *);
1585 int sock_no_setsockopt(struct socket *, int, int, char __user *, unsigned int);
1586 int sock_no_sendmsg(struct socket *, struct msghdr *, size_t);
1587 int sock_no_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t len);
1588 int sock_no_recvmsg(struct socket *, struct msghdr *, size_t, int);
1589 int sock_no_mmap(struct file *file, struct socket *sock,
1590 		 struct vm_area_struct *vma);
1591 ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset,
1592 			 size_t size, int flags);
1593 ssize_t sock_no_sendpage_locked(struct sock *sk, struct page *page,
1594 				int offset, size_t size, int flags);
1595 
1596 /*
1597  * Functions to fill in entries in struct proto_ops when a protocol
1598  * uses the inet style.
1599  */
1600 int sock_common_getsockopt(struct socket *sock, int level, int optname,
1601 				  char __user *optval, int __user *optlen);
1602 int sock_common_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1603 			int flags);
1604 int sock_common_setsockopt(struct socket *sock, int level, int optname,
1605 				  char __user *optval, unsigned int optlen);
1606 int compat_sock_common_getsockopt(struct socket *sock, int level,
1607 		int optname, char __user *optval, int __user *optlen);
1608 int compat_sock_common_setsockopt(struct socket *sock, int level,
1609 		int optname, char __user *optval, unsigned int optlen);
1610 
1611 void sk_common_release(struct sock *sk);
1612 
1613 /*
1614  *	Default socket callbacks and setup code
1615  */
1616 
1617 /* Initialise core socket variables */
1618 void sock_init_data(struct socket *sock, struct sock *sk);
1619 
1620 /*
1621  * Socket reference counting postulates.
1622  *
1623  * * Each user of socket SHOULD hold a reference count.
1624  * * Each access point to socket (an hash table bucket, reference from a list,
1625  *   running timer, skb in flight MUST hold a reference count.
1626  * * When reference count hits 0, it means it will never increase back.
1627  * * When reference count hits 0, it means that no references from
1628  *   outside exist to this socket and current process on current CPU
1629  *   is last user and may/should destroy this socket.
1630  * * sk_free is called from any context: process, BH, IRQ. When
1631  *   it is called, socket has no references from outside -> sk_free
1632  *   may release descendant resources allocated by the socket, but
1633  *   to the time when it is called, socket is NOT referenced by any
1634  *   hash tables, lists etc.
1635  * * Packets, delivered from outside (from network or from another process)
1636  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1637  *   when they sit in queue. Otherwise, packets will leak to hole, when
1638  *   socket is looked up by one cpu and unhasing is made by another CPU.
1639  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1640  *   (leak to backlog). Packet socket does all the processing inside
1641  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1642  *   use separate SMP lock, so that they are prone too.
1643  */
1644 
1645 /* Ungrab socket and destroy it, if it was the last reference. */
1646 static inline void sock_put(struct sock *sk)
1647 {
1648 	if (refcount_dec_and_test(&sk->sk_refcnt))
1649 		sk_free(sk);
1650 }
1651 /* Generic version of sock_put(), dealing with all sockets
1652  * (TCP_TIMEWAIT, TCP_NEW_SYN_RECV, ESTABLISHED...)
1653  */
1654 void sock_gen_put(struct sock *sk);
1655 
1656 int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested,
1657 		     unsigned int trim_cap, bool refcounted);
1658 static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1659 				 const int nested)
1660 {
1661 	return __sk_receive_skb(sk, skb, nested, 1, true);
1662 }
1663 
1664 static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
1665 {
1666 	sk->sk_tx_queue_mapping = tx_queue;
1667 }
1668 
1669 static inline void sk_tx_queue_clear(struct sock *sk)
1670 {
1671 	sk->sk_tx_queue_mapping = -1;
1672 }
1673 
1674 static inline int sk_tx_queue_get(const struct sock *sk)
1675 {
1676 	return sk ? sk->sk_tx_queue_mapping : -1;
1677 }
1678 
1679 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1680 {
1681 	sk_tx_queue_clear(sk);
1682 	sk->sk_socket = sock;
1683 }
1684 
1685 static inline wait_queue_head_t *sk_sleep(struct sock *sk)
1686 {
1687 	BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
1688 	return &rcu_dereference_raw(sk->sk_wq)->wait;
1689 }
1690 /* Detach socket from process context.
1691  * Announce socket dead, detach it from wait queue and inode.
1692  * Note that parent inode held reference count on this struct sock,
1693  * we do not release it in this function, because protocol
1694  * probably wants some additional cleanups or even continuing
1695  * to work with this socket (TCP).
1696  */
1697 static inline void sock_orphan(struct sock *sk)
1698 {
1699 	write_lock_bh(&sk->sk_callback_lock);
1700 	sock_set_flag(sk, SOCK_DEAD);
1701 	sk_set_socket(sk, NULL);
1702 	sk->sk_wq  = NULL;
1703 	write_unlock_bh(&sk->sk_callback_lock);
1704 }
1705 
1706 static inline void sock_graft(struct sock *sk, struct socket *parent)
1707 {
1708 	WARN_ON(parent->sk);
1709 	write_lock_bh(&sk->sk_callback_lock);
1710 	sk->sk_wq = parent->wq;
1711 	parent->sk = sk;
1712 	sk_set_socket(sk, parent);
1713 	sk->sk_uid = SOCK_INODE(parent)->i_uid;
1714 	security_sock_graft(sk, parent);
1715 	write_unlock_bh(&sk->sk_callback_lock);
1716 }
1717 
1718 kuid_t sock_i_uid(struct sock *sk);
1719 unsigned long sock_i_ino(struct sock *sk);
1720 
1721 static inline kuid_t sock_net_uid(const struct net *net, const struct sock *sk)
1722 {
1723 	return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
1724 }
1725 
1726 static inline u32 net_tx_rndhash(void)
1727 {
1728 	u32 v = prandom_u32();
1729 
1730 	return v ?: 1;
1731 }
1732 
1733 static inline void sk_set_txhash(struct sock *sk)
1734 {
1735 	sk->sk_txhash = net_tx_rndhash();
1736 }
1737 
1738 static inline void sk_rethink_txhash(struct sock *sk)
1739 {
1740 	if (sk->sk_txhash)
1741 		sk_set_txhash(sk);
1742 }
1743 
1744 static inline struct dst_entry *
1745 __sk_dst_get(struct sock *sk)
1746 {
1747 	return rcu_dereference_check(sk->sk_dst_cache,
1748 				     lockdep_sock_is_held(sk));
1749 }
1750 
1751 static inline struct dst_entry *
1752 sk_dst_get(struct sock *sk)
1753 {
1754 	struct dst_entry *dst;
1755 
1756 	rcu_read_lock();
1757 	dst = rcu_dereference(sk->sk_dst_cache);
1758 	if (dst && !atomic_inc_not_zero(&dst->__refcnt))
1759 		dst = NULL;
1760 	rcu_read_unlock();
1761 	return dst;
1762 }
1763 
1764 static inline void dst_negative_advice(struct sock *sk)
1765 {
1766 	struct dst_entry *ndst, *dst = __sk_dst_get(sk);
1767 
1768 	sk_rethink_txhash(sk);
1769 
1770 	if (dst && dst->ops->negative_advice) {
1771 		ndst = dst->ops->negative_advice(dst);
1772 
1773 		if (ndst != dst) {
1774 			rcu_assign_pointer(sk->sk_dst_cache, ndst);
1775 			sk_tx_queue_clear(sk);
1776 			sk->sk_dst_pending_confirm = 0;
1777 		}
1778 	}
1779 }
1780 
1781 static inline void
1782 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1783 {
1784 	struct dst_entry *old_dst;
1785 
1786 	sk_tx_queue_clear(sk);
1787 	sk->sk_dst_pending_confirm = 0;
1788 	old_dst = rcu_dereference_protected(sk->sk_dst_cache,
1789 					    lockdep_sock_is_held(sk));
1790 	rcu_assign_pointer(sk->sk_dst_cache, dst);
1791 	dst_release(old_dst);
1792 }
1793 
1794 static inline void
1795 sk_dst_set(struct sock *sk, struct dst_entry *dst)
1796 {
1797 	struct dst_entry *old_dst;
1798 
1799 	sk_tx_queue_clear(sk);
1800 	sk->sk_dst_pending_confirm = 0;
1801 	old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
1802 	dst_release(old_dst);
1803 }
1804 
1805 static inline void
1806 __sk_dst_reset(struct sock *sk)
1807 {
1808 	__sk_dst_set(sk, NULL);
1809 }
1810 
1811 static inline void
1812 sk_dst_reset(struct sock *sk)
1813 {
1814 	sk_dst_set(sk, NULL);
1815 }
1816 
1817 struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1818 
1819 struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1820 
1821 static inline void sk_dst_confirm(struct sock *sk)
1822 {
1823 	if (!sk->sk_dst_pending_confirm)
1824 		sk->sk_dst_pending_confirm = 1;
1825 }
1826 
1827 static inline void sock_confirm_neigh(struct sk_buff *skb, struct neighbour *n)
1828 {
1829 	if (skb_get_dst_pending_confirm(skb)) {
1830 		struct sock *sk = skb->sk;
1831 		unsigned long now = jiffies;
1832 
1833 		/* avoid dirtying neighbour */
1834 		if (n->confirmed != now)
1835 			n->confirmed = now;
1836 		if (sk && sk->sk_dst_pending_confirm)
1837 			sk->sk_dst_pending_confirm = 0;
1838 	}
1839 }
1840 
1841 bool sk_mc_loop(struct sock *sk);
1842 
1843 static inline bool sk_can_gso(const struct sock *sk)
1844 {
1845 	return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
1846 }
1847 
1848 void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
1849 
1850 static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
1851 {
1852 	sk->sk_route_nocaps |= flags;
1853 	sk->sk_route_caps &= ~flags;
1854 }
1855 
1856 static inline bool sk_check_csum_caps(struct sock *sk)
1857 {
1858 	return (sk->sk_route_caps & NETIF_F_HW_CSUM) ||
1859 	       (sk->sk_family == PF_INET &&
1860 		(sk->sk_route_caps & NETIF_F_IP_CSUM)) ||
1861 	       (sk->sk_family == PF_INET6 &&
1862 		(sk->sk_route_caps & NETIF_F_IPV6_CSUM));
1863 }
1864 
1865 static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
1866 					   struct iov_iter *from, char *to,
1867 					   int copy, int offset)
1868 {
1869 	if (skb->ip_summed == CHECKSUM_NONE) {
1870 		__wsum csum = 0;
1871 		if (!csum_and_copy_from_iter_full(to, copy, &csum, from))
1872 			return -EFAULT;
1873 		skb->csum = csum_block_add(skb->csum, csum, offset);
1874 	} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
1875 		if (!copy_from_iter_full_nocache(to, copy, from))
1876 			return -EFAULT;
1877 	} else if (!copy_from_iter_full(to, copy, from))
1878 		return -EFAULT;
1879 
1880 	return 0;
1881 }
1882 
1883 static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
1884 				       struct iov_iter *from, int copy)
1885 {
1886 	int err, offset = skb->len;
1887 
1888 	err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
1889 				       copy, offset);
1890 	if (err)
1891 		__skb_trim(skb, offset);
1892 
1893 	return err;
1894 }
1895 
1896 static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *from,
1897 					   struct sk_buff *skb,
1898 					   struct page *page,
1899 					   int off, int copy)
1900 {
1901 	int err;
1902 
1903 	err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
1904 				       copy, skb->len);
1905 	if (err)
1906 		return err;
1907 
1908 	skb->len	     += copy;
1909 	skb->data_len	     += copy;
1910 	skb->truesize	     += copy;
1911 	sk->sk_wmem_queued   += copy;
1912 	sk_mem_charge(sk, copy);
1913 	return 0;
1914 }
1915 
1916 /**
1917  * sk_wmem_alloc_get - returns write allocations
1918  * @sk: socket
1919  *
1920  * Returns sk_wmem_alloc minus initial offset of one
1921  */
1922 static inline int sk_wmem_alloc_get(const struct sock *sk)
1923 {
1924 	return refcount_read(&sk->sk_wmem_alloc) - 1;
1925 }
1926 
1927 /**
1928  * sk_rmem_alloc_get - returns read allocations
1929  * @sk: socket
1930  *
1931  * Returns sk_rmem_alloc
1932  */
1933 static inline int sk_rmem_alloc_get(const struct sock *sk)
1934 {
1935 	return atomic_read(&sk->sk_rmem_alloc);
1936 }
1937 
1938 /**
1939  * sk_has_allocations - check if allocations are outstanding
1940  * @sk: socket
1941  *
1942  * Returns true if socket has write or read allocations
1943  */
1944 static inline bool sk_has_allocations(const struct sock *sk)
1945 {
1946 	return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
1947 }
1948 
1949 /**
1950  * skwq_has_sleeper - check if there are any waiting processes
1951  * @wq: struct socket_wq
1952  *
1953  * Returns true if socket_wq has waiting processes
1954  *
1955  * The purpose of the skwq_has_sleeper and sock_poll_wait is to wrap the memory
1956  * barrier call. They were added due to the race found within the tcp code.
1957  *
1958  * Consider following tcp code paths::
1959  *
1960  *   CPU1                CPU2
1961  *   sys_select          receive packet
1962  *   ...                 ...
1963  *   __add_wait_queue    update tp->rcv_nxt
1964  *   ...                 ...
1965  *   tp->rcv_nxt check   sock_def_readable
1966  *   ...                 {
1967  *   schedule               rcu_read_lock();
1968  *                          wq = rcu_dereference(sk->sk_wq);
1969  *                          if (wq && waitqueue_active(&wq->wait))
1970  *                              wake_up_interruptible(&wq->wait)
1971  *                          ...
1972  *                       }
1973  *
1974  * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
1975  * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
1976  * could then endup calling schedule and sleep forever if there are no more
1977  * data on the socket.
1978  *
1979  */
1980 static inline bool skwq_has_sleeper(struct socket_wq *wq)
1981 {
1982 	return wq && wq_has_sleeper(&wq->wait);
1983 }
1984 
1985 /**
1986  * sock_poll_wait - place memory barrier behind the poll_wait call.
1987  * @filp:           file
1988  * @wait_address:   socket wait queue
1989  * @p:              poll_table
1990  *
1991  * See the comments in the wq_has_sleeper function.
1992  */
1993 static inline void sock_poll_wait(struct file *filp,
1994 		wait_queue_head_t *wait_address, poll_table *p)
1995 {
1996 	if (!poll_does_not_wait(p) && wait_address) {
1997 		poll_wait(filp, wait_address, p);
1998 		/* We need to be sure we are in sync with the
1999 		 * socket flags modification.
2000 		 *
2001 		 * This memory barrier is paired in the wq_has_sleeper.
2002 		 */
2003 		smp_mb();
2004 	}
2005 }
2006 
2007 static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)
2008 {
2009 	if (sk->sk_txhash) {
2010 		skb->l4_hash = 1;
2011 		skb->hash = sk->sk_txhash;
2012 	}
2013 }
2014 
2015 void skb_set_owner_w(struct sk_buff *skb, struct sock *sk);
2016 
2017 /*
2018  *	Queue a received datagram if it will fit. Stream and sequenced
2019  *	protocols can't normally use this as they need to fit buffers in
2020  *	and play with them.
2021  *
2022  *	Inlined as it's very short and called for pretty much every
2023  *	packet ever received.
2024  */
2025 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
2026 {
2027 	skb_orphan(skb);
2028 	skb->sk = sk;
2029 	skb->destructor = sock_rfree;
2030 	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
2031 	sk_mem_charge(sk, skb->truesize);
2032 }
2033 
2034 void sk_reset_timer(struct sock *sk, struct timer_list *timer,
2035 		    unsigned long expires);
2036 
2037 void sk_stop_timer(struct sock *sk, struct timer_list *timer);
2038 
2039 int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue,
2040 			struct sk_buff *skb, unsigned int flags,
2041 			void (*destructor)(struct sock *sk,
2042 					   struct sk_buff *skb));
2043 int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2044 int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2045 
2046 int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
2047 struct sk_buff *sock_dequeue_err_skb(struct sock *sk);
2048 
2049 /*
2050  *	Recover an error report and clear atomically
2051  */
2052 
2053 static inline int sock_error(struct sock *sk)
2054 {
2055 	int err;
2056 	if (likely(!sk->sk_err))
2057 		return 0;
2058 	err = xchg(&sk->sk_err, 0);
2059 	return -err;
2060 }
2061 
2062 static inline unsigned long sock_wspace(struct sock *sk)
2063 {
2064 	int amt = 0;
2065 
2066 	if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
2067 		amt = sk->sk_sndbuf - refcount_read(&sk->sk_wmem_alloc);
2068 		if (amt < 0)
2069 			amt = 0;
2070 	}
2071 	return amt;
2072 }
2073 
2074 /* Note:
2075  *  We use sk->sk_wq_raw, from contexts knowing this
2076  *  pointer is not NULL and cannot disappear/change.
2077  */
2078 static inline void sk_set_bit(int nr, struct sock *sk)
2079 {
2080 	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2081 	    !sock_flag(sk, SOCK_FASYNC))
2082 		return;
2083 
2084 	set_bit(nr, &sk->sk_wq_raw->flags);
2085 }
2086 
2087 static inline void sk_clear_bit(int nr, struct sock *sk)
2088 {
2089 	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2090 	    !sock_flag(sk, SOCK_FASYNC))
2091 		return;
2092 
2093 	clear_bit(nr, &sk->sk_wq_raw->flags);
2094 }
2095 
2096 static inline void sk_wake_async(const struct sock *sk, int how, int band)
2097 {
2098 	if (sock_flag(sk, SOCK_FASYNC)) {
2099 		rcu_read_lock();
2100 		sock_wake_async(rcu_dereference(sk->sk_wq), how, band);
2101 		rcu_read_unlock();
2102 	}
2103 }
2104 
2105 /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
2106  * need sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak.
2107  * Note: for send buffers, TCP works better if we can build two skbs at
2108  * minimum.
2109  */
2110 #define TCP_SKB_MIN_TRUESIZE	(2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
2111 
2112 #define SOCK_MIN_SNDBUF		(TCP_SKB_MIN_TRUESIZE * 2)
2113 #define SOCK_MIN_RCVBUF		 TCP_SKB_MIN_TRUESIZE
2114 
2115 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
2116 {
2117 	if (!(sk->sk_userlocks & SOCK_SNDBUF_LOCK)) {
2118 		sk->sk_sndbuf = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
2119 		sk->sk_sndbuf = max_t(u32, sk->sk_sndbuf, SOCK_MIN_SNDBUF);
2120 	}
2121 }
2122 
2123 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
2124 				    bool force_schedule);
2125 
2126 /**
2127  * sk_page_frag - return an appropriate page_frag
2128  * @sk: socket
2129  *
2130  * If socket allocation mode allows current thread to sleep, it means its
2131  * safe to use the per task page_frag instead of the per socket one.
2132  */
2133 static inline struct page_frag *sk_page_frag(struct sock *sk)
2134 {
2135 	if (gfpflags_allow_blocking(sk->sk_allocation))
2136 		return &current->task_frag;
2137 
2138 	return &sk->sk_frag;
2139 }
2140 
2141 bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
2142 
2143 /*
2144  *	Default write policy as shown to user space via poll/select/SIGIO
2145  */
2146 static inline bool sock_writeable(const struct sock *sk)
2147 {
2148 	return refcount_read(&sk->sk_wmem_alloc) < (sk->sk_sndbuf >> 1);
2149 }
2150 
2151 static inline gfp_t gfp_any(void)
2152 {
2153 	return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
2154 }
2155 
2156 static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2157 {
2158 	return noblock ? 0 : sk->sk_rcvtimeo;
2159 }
2160 
2161 static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2162 {
2163 	return noblock ? 0 : sk->sk_sndtimeo;
2164 }
2165 
2166 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2167 {
2168 	return (waitall ? len : min_t(int, sk->sk_rcvlowat, len)) ? : 1;
2169 }
2170 
2171 /* Alas, with timeout socket operations are not restartable.
2172  * Compare this to poll().
2173  */
2174 static inline int sock_intr_errno(long timeo)
2175 {
2176 	return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2177 }
2178 
2179 struct sock_skb_cb {
2180 	u32 dropcount;
2181 };
2182 
2183 /* Store sock_skb_cb at the end of skb->cb[] so protocol families
2184  * using skb->cb[] would keep using it directly and utilize its
2185  * alignement guarantee.
2186  */
2187 #define SOCK_SKB_CB_OFFSET ((FIELD_SIZEOF(struct sk_buff, cb) - \
2188 			    sizeof(struct sock_skb_cb)))
2189 
2190 #define SOCK_SKB_CB(__skb) ((struct sock_skb_cb *)((__skb)->cb + \
2191 			    SOCK_SKB_CB_OFFSET))
2192 
2193 #define sock_skb_cb_check_size(size) \
2194 	BUILD_BUG_ON((size) > SOCK_SKB_CB_OFFSET)
2195 
2196 static inline void
2197 sock_skb_set_dropcount(const struct sock *sk, struct sk_buff *skb)
2198 {
2199 	SOCK_SKB_CB(skb)->dropcount = sock_flag(sk, SOCK_RXQ_OVFL) ?
2200 						atomic_read(&sk->sk_drops) : 0;
2201 }
2202 
2203 static inline void sk_drops_add(struct sock *sk, const struct sk_buff *skb)
2204 {
2205 	int segs = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
2206 
2207 	atomic_add(segs, &sk->sk_drops);
2208 }
2209 
2210 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2211 			   struct sk_buff *skb);
2212 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2213 			     struct sk_buff *skb);
2214 
2215 static inline void
2216 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2217 {
2218 	ktime_t kt = skb->tstamp;
2219 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2220 
2221 	/*
2222 	 * generate control messages if
2223 	 * - receive time stamping in software requested
2224 	 * - software time stamp available and wanted
2225 	 * - hardware time stamps available and wanted
2226 	 */
2227 	if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2228 	    (sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
2229 	    (kt && sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
2230 	    (hwtstamps->hwtstamp &&
2231 	     (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
2232 		__sock_recv_timestamp(msg, sk, skb);
2233 	else
2234 		sk->sk_stamp = kt;
2235 
2236 	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2237 		__sock_recv_wifi_status(msg, sk, skb);
2238 }
2239 
2240 void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2241 			      struct sk_buff *skb);
2242 
2243 #define SK_DEFAULT_STAMP (-1L * NSEC_PER_SEC)
2244 static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2245 					  struct sk_buff *skb)
2246 {
2247 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)			| \
2248 			   (1UL << SOCK_RCVTSTAMP))
2249 #define TSFLAGS_ANY	  (SOF_TIMESTAMPING_SOFTWARE			| \
2250 			   SOF_TIMESTAMPING_RAW_HARDWARE)
2251 
2252 	if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY)
2253 		__sock_recv_ts_and_drops(msg, sk, skb);
2254 	else if (unlikely(sock_flag(sk, SOCK_TIMESTAMP)))
2255 		sk->sk_stamp = skb->tstamp;
2256 	else if (unlikely(sk->sk_stamp == SK_DEFAULT_STAMP))
2257 		sk->sk_stamp = 0;
2258 }
2259 
2260 void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags);
2261 
2262 /**
2263  * sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2264  * @sk:		socket sending this packet
2265  * @tsflags:	timestamping flags to use
2266  * @tx_flags:	completed with instructions for time stamping
2267  *
2268  * Note: callers should take care of initial ``*tx_flags`` value (usually 0)
2269  */
2270 static inline void sock_tx_timestamp(const struct sock *sk, __u16 tsflags,
2271 				     __u8 *tx_flags)
2272 {
2273 	if (unlikely(tsflags))
2274 		__sock_tx_timestamp(tsflags, tx_flags);
2275 	if (unlikely(sock_flag(sk, SOCK_WIFI_STATUS)))
2276 		*tx_flags |= SKBTX_WIFI_STATUS;
2277 }
2278 
2279 /**
2280  * sk_eat_skb - Release a skb if it is no longer needed
2281  * @sk: socket to eat this skb from
2282  * @skb: socket buffer to eat
2283  *
2284  * This routine must be called with interrupts disabled or with the socket
2285  * locked so that the sk_buff queue operation is ok.
2286 */
2287 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb)
2288 {
2289 	__skb_unlink(skb, &sk->sk_receive_queue);
2290 	__kfree_skb(skb);
2291 }
2292 
2293 static inline
2294 struct net *sock_net(const struct sock *sk)
2295 {
2296 	return read_pnet(&sk->sk_net);
2297 }
2298 
2299 static inline
2300 void sock_net_set(struct sock *sk, struct net *net)
2301 {
2302 	write_pnet(&sk->sk_net, net);
2303 }
2304 
2305 static inline struct sock *skb_steal_sock(struct sk_buff *skb)
2306 {
2307 	if (skb->sk) {
2308 		struct sock *sk = skb->sk;
2309 
2310 		skb->destructor = NULL;
2311 		skb->sk = NULL;
2312 		return sk;
2313 	}
2314 	return NULL;
2315 }
2316 
2317 /* This helper checks if a socket is a full socket,
2318  * ie _not_ a timewait or request socket.
2319  */
2320 static inline bool sk_fullsock(const struct sock *sk)
2321 {
2322 	return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
2323 }
2324 
2325 /* This helper checks if a socket is a LISTEN or NEW_SYN_RECV
2326  * SYNACK messages can be attached to either ones (depending on SYNCOOKIE)
2327  */
2328 static inline bool sk_listener(const struct sock *sk)
2329 {
2330 	return (1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV);
2331 }
2332 
2333 /**
2334  * sk_state_load - read sk->sk_state for lockless contexts
2335  * @sk: socket pointer
2336  *
2337  * Paired with sk_state_store(). Used in places we do not hold socket lock :
2338  * tcp_diag_get_info(), tcp_get_info(), tcp_poll(), get_tcp4_sock() ...
2339  */
2340 static inline int sk_state_load(const struct sock *sk)
2341 {
2342 	return smp_load_acquire(&sk->sk_state);
2343 }
2344 
2345 /**
2346  * sk_state_store - update sk->sk_state
2347  * @sk: socket pointer
2348  * @newstate: new state
2349  *
2350  * Paired with sk_state_load(). Should be used in contexts where
2351  * state change might impact lockless readers.
2352  */
2353 static inline void sk_state_store(struct sock *sk, int newstate)
2354 {
2355 	smp_store_release(&sk->sk_state, newstate);
2356 }
2357 
2358 void sock_enable_timestamp(struct sock *sk, int flag);
2359 int sock_get_timestamp(struct sock *, struct timeval __user *);
2360 int sock_get_timestampns(struct sock *, struct timespec __user *);
2361 int sock_recv_errqueue(struct sock *sk, struct msghdr *msg, int len, int level,
2362 		       int type);
2363 
2364 bool sk_ns_capable(const struct sock *sk,
2365 		   struct user_namespace *user_ns, int cap);
2366 bool sk_capable(const struct sock *sk, int cap);
2367 bool sk_net_capable(const struct sock *sk, int cap);
2368 
2369 void sk_get_meminfo(const struct sock *sk, u32 *meminfo);
2370 
2371 /* Take into consideration the size of the struct sk_buff overhead in the
2372  * determination of these values, since that is non-constant across
2373  * platforms.  This makes socket queueing behavior and performance
2374  * not depend upon such differences.
2375  */
2376 #define _SK_MEM_PACKETS		256
2377 #define _SK_MEM_OVERHEAD	SKB_TRUESIZE(256)
2378 #define SK_WMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2379 #define SK_RMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2380 
2381 extern __u32 sysctl_wmem_max;
2382 extern __u32 sysctl_rmem_max;
2383 
2384 extern int sysctl_tstamp_allow_data;
2385 extern int sysctl_optmem_max;
2386 
2387 extern __u32 sysctl_wmem_default;
2388 extern __u32 sysctl_rmem_default;
2389 
2390 #endif	/* _SOCK_H */
2391