xref: /linux/include/net/sock.h (revision d1626a1c273d0e66834006b10ebe12062dce2b6f)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * INET		An implementation of the TCP/IP protocol suite for the LINUX
4  *		operating system.  INET is implemented using the  BSD Socket
5  *		interface as the means of communication with the user level.
6  *
7  *		Definitions for the AF_INET socket handler.
8  *
9  * Version:	@(#)sock.h	1.0.4	05/13/93
10  *
11  * Authors:	Ross Biro
12  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13  *		Corey Minyard <wf-rch!minyard@relay.EU.net>
14  *		Florian La Roche <flla@stud.uni-sb.de>
15  *
16  * Fixes:
17  *		Alan Cox	:	Volatiles in skbuff pointers. See
18  *					skbuff comments. May be overdone,
19  *					better to prove they can be removed
20  *					than the reverse.
21  *		Alan Cox	:	Added a zapped field for tcp to note
22  *					a socket is reset and must stay shut up
23  *		Alan Cox	:	New fields for options
24  *	Pauline Middelink	:	identd support
25  *		Alan Cox	:	Eliminate low level recv/recvfrom
26  *		David S. Miller	:	New socket lookup architecture.
27  *              Steve Whitehouse:       Default routines for sock_ops
28  *              Arnaldo C. Melo :	removed net_pinfo, tp_pinfo and made
29  *              			protinfo be just a void pointer, as the
30  *              			protocol specific parts were moved to
31  *              			respective headers and ipv4/v6, etc now
32  *              			use private slabcaches for its socks
33  *              Pedro Hortas	:	New flags field for socket options
34  */
35 #ifndef _SOCK_H
36 #define _SOCK_H
37 
38 #include <linux/hardirq.h>
39 #include <linux/kernel.h>
40 #include <linux/list.h>
41 #include <linux/list_nulls.h>
42 #include <linux/timer.h>
43 #include <linux/cache.h>
44 #include <linux/bitops.h>
45 #include <linux/lockdep.h>
46 #include <linux/netdevice.h>
47 #include <linux/skbuff.h>	/* struct sk_buff */
48 #include <linux/mm.h>
49 #include <linux/security.h>
50 #include <linux/slab.h>
51 #include <linux/uaccess.h>
52 #include <linux/page_counter.h>
53 #include <linux/memcontrol.h>
54 #include <linux/static_key.h>
55 #include <linux/sched.h>
56 #include <linux/wait.h>
57 #include <linux/cgroup-defs.h>
58 #include <linux/rbtree.h>
59 #include <linux/filter.h>
60 #include <linux/rculist_nulls.h>
61 #include <linux/poll.h>
62 #include <linux/sockptr.h>
63 #include <linux/indirect_call_wrapper.h>
64 #include <linux/atomic.h>
65 #include <linux/refcount.h>
66 #include <net/dst.h>
67 #include <net/checksum.h>
68 #include <net/tcp_states.h>
69 #include <linux/net_tstamp.h>
70 #include <net/l3mdev.h>
71 
72 /*
73  * This structure really needs to be cleaned up.
74  * Most of it is for TCP, and not used by any of
75  * the other protocols.
76  */
77 
78 /* Define this to get the SOCK_DBG debugging facility. */
79 #define SOCK_DEBUGGING
80 #ifdef SOCK_DEBUGGING
81 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
82 					printk(KERN_DEBUG msg); } while (0)
83 #else
84 /* Validate arguments and do nothing */
85 static inline __printf(2, 3)
86 void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
87 {
88 }
89 #endif
90 
91 /* This is the per-socket lock.  The spinlock provides a synchronization
92  * between user contexts and software interrupt processing, whereas the
93  * mini-semaphore synchronizes multiple users amongst themselves.
94  */
95 typedef struct {
96 	spinlock_t		slock;
97 	int			owned;
98 	wait_queue_head_t	wq;
99 	/*
100 	 * We express the mutex-alike socket_lock semantics
101 	 * to the lock validator by explicitly managing
102 	 * the slock as a lock variant (in addition to
103 	 * the slock itself):
104 	 */
105 #ifdef CONFIG_DEBUG_LOCK_ALLOC
106 	struct lockdep_map dep_map;
107 #endif
108 } socket_lock_t;
109 
110 struct sock;
111 struct proto;
112 struct net;
113 
114 typedef __u32 __bitwise __portpair;
115 typedef __u64 __bitwise __addrpair;
116 
117 /**
118  *	struct sock_common - minimal network layer representation of sockets
119  *	@skc_daddr: Foreign IPv4 addr
120  *	@skc_rcv_saddr: Bound local IPv4 addr
121  *	@skc_addrpair: 8-byte-aligned __u64 union of @skc_daddr & @skc_rcv_saddr
122  *	@skc_hash: hash value used with various protocol lookup tables
123  *	@skc_u16hashes: two u16 hash values used by UDP lookup tables
124  *	@skc_dport: placeholder for inet_dport/tw_dport
125  *	@skc_num: placeholder for inet_num/tw_num
126  *	@skc_portpair: __u32 union of @skc_dport & @skc_num
127  *	@skc_family: network address family
128  *	@skc_state: Connection state
129  *	@skc_reuse: %SO_REUSEADDR setting
130  *	@skc_reuseport: %SO_REUSEPORT setting
131  *	@skc_ipv6only: socket is IPV6 only
132  *	@skc_net_refcnt: socket is using net ref counting
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_v6_daddr: IPV6 destination address
139  *	@skc_v6_rcv_saddr: IPV6 source address
140  *	@skc_cookie: socket's cookie value
141  *	@skc_node: main hash linkage for various protocol lookup tables
142  *	@skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
143  *	@skc_tx_queue_mapping: tx queue number for this connection
144  *	@skc_rx_queue_mapping: rx queue number for this connection
145  *	@skc_flags: place holder for sk_flags
146  *		%SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
147  *		%SO_OOBINLINE settings, %SO_TIMESTAMPING settings
148  *	@skc_listener: connection request listener socket (aka rsk_listener)
149  *		[union with @skc_flags]
150  *	@skc_tw_dr: (aka tw_dr) ptr to &struct inet_timewait_death_row
151  *		[union with @skc_flags]
152  *	@skc_incoming_cpu: record/match cpu processing incoming packets
153  *	@skc_rcv_wnd: (aka rsk_rcv_wnd) TCP receive window size (possibly scaled)
154  *		[union with @skc_incoming_cpu]
155  *	@skc_tw_rcv_nxt: (aka tw_rcv_nxt) TCP window next expected seq number
156  *		[union with @skc_incoming_cpu]
157  *	@skc_refcnt: reference count
158  *
159  *	This is the minimal network layer representation of sockets, the header
160  *	for struct sock and struct inet_timewait_sock.
161  */
162 struct sock_common {
163 	/* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned
164 	 * address on 64bit arches : cf INET_MATCH()
165 	 */
166 	union {
167 		__addrpair	skc_addrpair;
168 		struct {
169 			__be32	skc_daddr;
170 			__be32	skc_rcv_saddr;
171 		};
172 	};
173 	union  {
174 		unsigned int	skc_hash;
175 		__u16		skc_u16hashes[2];
176 	};
177 	/* skc_dport && skc_num must be grouped as well */
178 	union {
179 		__portpair	skc_portpair;
180 		struct {
181 			__be16	skc_dport;
182 			__u16	skc_num;
183 		};
184 	};
185 
186 	unsigned short		skc_family;
187 	volatile unsigned char	skc_state;
188 	unsigned char		skc_reuse:4;
189 	unsigned char		skc_reuseport:1;
190 	unsigned char		skc_ipv6only:1;
191 	unsigned char		skc_net_refcnt:1;
192 	int			skc_bound_dev_if;
193 	union {
194 		struct hlist_node	skc_bind_node;
195 		struct hlist_node	skc_portaddr_node;
196 	};
197 	struct proto		*skc_prot;
198 	possible_net_t		skc_net;
199 
200 #if IS_ENABLED(CONFIG_IPV6)
201 	struct in6_addr		skc_v6_daddr;
202 	struct in6_addr		skc_v6_rcv_saddr;
203 #endif
204 
205 	atomic64_t		skc_cookie;
206 
207 	/* following fields are padding to force
208 	 * offset(struct sock, sk_refcnt) == 128 on 64bit arches
209 	 * assuming IPV6 is enabled. We use this padding differently
210 	 * for different kind of 'sockets'
211 	 */
212 	union {
213 		unsigned long	skc_flags;
214 		struct sock	*skc_listener; /* request_sock */
215 		struct inet_timewait_death_row *skc_tw_dr; /* inet_timewait_sock */
216 	};
217 	/*
218 	 * fields between dontcopy_begin/dontcopy_end
219 	 * are not copied in sock_copy()
220 	 */
221 	/* private: */
222 	int			skc_dontcopy_begin[0];
223 	/* public: */
224 	union {
225 		struct hlist_node	skc_node;
226 		struct hlist_nulls_node skc_nulls_node;
227 	};
228 	unsigned short		skc_tx_queue_mapping;
229 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
230 	unsigned short		skc_rx_queue_mapping;
231 #endif
232 	union {
233 		int		skc_incoming_cpu;
234 		u32		skc_rcv_wnd;
235 		u32		skc_tw_rcv_nxt; /* struct tcp_timewait_sock  */
236 	};
237 
238 	refcount_t		skc_refcnt;
239 	/* private: */
240 	int                     skc_dontcopy_end[0];
241 	union {
242 		u32		skc_rxhash;
243 		u32		skc_window_clamp;
244 		u32		skc_tw_snd_nxt; /* struct tcp_timewait_sock */
245 	};
246 	/* public: */
247 };
248 
249 struct bpf_local_storage;
250 
251 /**
252   *	struct sock - network layer representation of sockets
253   *	@__sk_common: shared layout with inet_timewait_sock
254   *	@sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
255   *	@sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
256   *	@sk_lock:	synchronizer
257   *	@sk_kern_sock: True if sock is using kernel lock classes
258   *	@sk_rcvbuf: size of receive buffer in bytes
259   *	@sk_wq: sock wait queue and async head
260   *	@sk_rx_dst: receive input route used by early demux
261   *	@sk_dst_cache: destination cache
262   *	@sk_dst_pending_confirm: need to confirm neighbour
263   *	@sk_policy: flow policy
264   *	@sk_rx_skb_cache: cache copy of recently accessed RX skb
265   *	@sk_receive_queue: incoming packets
266   *	@sk_wmem_alloc: transmit queue bytes committed
267   *	@sk_tsq_flags: TCP Small Queues flags
268   *	@sk_write_queue: Packet sending queue
269   *	@sk_omem_alloc: "o" is "option" or "other"
270   *	@sk_wmem_queued: persistent queue size
271   *	@sk_forward_alloc: space allocated forward
272   *	@sk_napi_id: id of the last napi context to receive data for sk
273   *	@sk_ll_usec: usecs to busypoll when there is no data
274   *	@sk_allocation: allocation mode
275   *	@sk_pacing_rate: Pacing rate (if supported by transport/packet scheduler)
276   *	@sk_pacing_status: Pacing status (requested, handled by sch_fq)
277   *	@sk_max_pacing_rate: Maximum pacing rate (%SO_MAX_PACING_RATE)
278   *	@sk_sndbuf: size of send buffer in bytes
279   *	@__sk_flags_offset: empty field used to determine location of bitfield
280   *	@sk_padding: unused element for alignment
281   *	@sk_no_check_tx: %SO_NO_CHECK setting, set checksum in TX packets
282   *	@sk_no_check_rx: allow zero checksum in RX packets
283   *	@sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
284   *	@sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
285   *	@sk_route_forced_caps: static, forced route capabilities
286   *		(set in tcp_init_sock())
287   *	@sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
288   *	@sk_gso_max_size: Maximum GSO segment size to build
289   *	@sk_gso_max_segs: Maximum number of GSO segments
290   *	@sk_pacing_shift: scaling factor for TCP Small Queues
291   *	@sk_lingertime: %SO_LINGER l_linger setting
292   *	@sk_backlog: always used with the per-socket spinlock held
293   *	@sk_callback_lock: used with the callbacks in the end of this struct
294   *	@sk_error_queue: rarely used
295   *	@sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
296   *			  IPV6_ADDRFORM for instance)
297   *	@sk_err: last error
298   *	@sk_err_soft: errors that don't cause failure but are the cause of a
299   *		      persistent failure not just 'timed out'
300   *	@sk_drops: raw/udp drops counter
301   *	@sk_ack_backlog: current listen backlog
302   *	@sk_max_ack_backlog: listen backlog set in listen()
303   *	@sk_uid: user id of owner
304   *	@sk_prefer_busy_poll: prefer busypolling over softirq processing
305   *	@sk_busy_poll_budget: napi processing budget when busypolling
306   *	@sk_priority: %SO_PRIORITY setting
307   *	@sk_type: socket type (%SOCK_STREAM, etc)
308   *	@sk_protocol: which protocol this socket belongs in this network family
309   *	@sk_peer_pid: &struct pid for this socket's peer
310   *	@sk_peer_cred: %SO_PEERCRED setting
311   *	@sk_rcvlowat: %SO_RCVLOWAT setting
312   *	@sk_rcvtimeo: %SO_RCVTIMEO setting
313   *	@sk_sndtimeo: %SO_SNDTIMEO setting
314   *	@sk_txhash: computed flow hash for use on transmit
315   *	@sk_filter: socket filtering instructions
316   *	@sk_timer: sock cleanup timer
317   *	@sk_stamp: time stamp of last packet received
318   *	@sk_stamp_seq: lock for accessing sk_stamp on 32 bit architectures only
319   *	@sk_tsflags: SO_TIMESTAMPING flags
320   *	@sk_bind_phc: SO_TIMESTAMPING bind PHC index of PTP virtual clock
321   *	              for timestamping
322   *	@sk_tskey: counter to disambiguate concurrent tstamp requests
323   *	@sk_zckey: counter to order MSG_ZEROCOPY notifications
324   *	@sk_socket: Identd and reporting IO signals
325   *	@sk_user_data: RPC layer private data
326   *	@sk_frag: cached page frag
327   *	@sk_peek_off: current peek_offset value
328   *	@sk_send_head: front of stuff to transmit
329   *	@tcp_rtx_queue: TCP re-transmit queue [union with @sk_send_head]
330   *	@sk_tx_skb_cache: cache copy of recently accessed TX skb
331   *	@sk_security: used by security modules
332   *	@sk_mark: generic packet mark
333   *	@sk_cgrp_data: cgroup data for this cgroup
334   *	@sk_memcg: this socket's memory cgroup association
335   *	@sk_write_pending: a write to stream socket waits to start
336   *	@sk_state_change: callback to indicate change in the state of the sock
337   *	@sk_data_ready: callback to indicate there is data to be processed
338   *	@sk_write_space: callback to indicate there is bf sending space available
339   *	@sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
340   *	@sk_backlog_rcv: callback to process the backlog
341   *	@sk_validate_xmit_skb: ptr to an optional validate function
342   *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
343   *	@sk_reuseport_cb: reuseport group container
344   *	@sk_bpf_storage: ptr to cache and control for bpf_sk_storage
345   *	@sk_rcu: used during RCU grace period
346   *	@sk_clockid: clockid used by time-based scheduling (SO_TXTIME)
347   *	@sk_txtime_deadline_mode: set deadline mode for SO_TXTIME
348   *	@sk_txtime_report_errors: set report errors mode for SO_TXTIME
349   *	@sk_txtime_unused: unused txtime flags
350   */
351 struct sock {
352 	/*
353 	 * Now struct inet_timewait_sock also uses sock_common, so please just
354 	 * don't add nothing before this first member (__sk_common) --acme
355 	 */
356 	struct sock_common	__sk_common;
357 #define sk_node			__sk_common.skc_node
358 #define sk_nulls_node		__sk_common.skc_nulls_node
359 #define sk_refcnt		__sk_common.skc_refcnt
360 #define sk_tx_queue_mapping	__sk_common.skc_tx_queue_mapping
361 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
362 #define sk_rx_queue_mapping	__sk_common.skc_rx_queue_mapping
363 #endif
364 
365 #define sk_dontcopy_begin	__sk_common.skc_dontcopy_begin
366 #define sk_dontcopy_end		__sk_common.skc_dontcopy_end
367 #define sk_hash			__sk_common.skc_hash
368 #define sk_portpair		__sk_common.skc_portpair
369 #define sk_num			__sk_common.skc_num
370 #define sk_dport		__sk_common.skc_dport
371 #define sk_addrpair		__sk_common.skc_addrpair
372 #define sk_daddr		__sk_common.skc_daddr
373 #define sk_rcv_saddr		__sk_common.skc_rcv_saddr
374 #define sk_family		__sk_common.skc_family
375 #define sk_state		__sk_common.skc_state
376 #define sk_reuse		__sk_common.skc_reuse
377 #define sk_reuseport		__sk_common.skc_reuseport
378 #define sk_ipv6only		__sk_common.skc_ipv6only
379 #define sk_net_refcnt		__sk_common.skc_net_refcnt
380 #define sk_bound_dev_if		__sk_common.skc_bound_dev_if
381 #define sk_bind_node		__sk_common.skc_bind_node
382 #define sk_prot			__sk_common.skc_prot
383 #define sk_net			__sk_common.skc_net
384 #define sk_v6_daddr		__sk_common.skc_v6_daddr
385 #define sk_v6_rcv_saddr	__sk_common.skc_v6_rcv_saddr
386 #define sk_cookie		__sk_common.skc_cookie
387 #define sk_incoming_cpu		__sk_common.skc_incoming_cpu
388 #define sk_flags		__sk_common.skc_flags
389 #define sk_rxhash		__sk_common.skc_rxhash
390 
391 	socket_lock_t		sk_lock;
392 	atomic_t		sk_drops;
393 	int			sk_rcvlowat;
394 	struct sk_buff_head	sk_error_queue;
395 	struct sk_buff		*sk_rx_skb_cache;
396 	struct sk_buff_head	sk_receive_queue;
397 	/*
398 	 * The backlog queue is special, it is always used with
399 	 * the per-socket spinlock held and requires low latency
400 	 * access. Therefore we special case it's implementation.
401 	 * Note : rmem_alloc is in this structure to fill a hole
402 	 * on 64bit arches, not because its logically part of
403 	 * backlog.
404 	 */
405 	struct {
406 		atomic_t	rmem_alloc;
407 		int		len;
408 		struct sk_buff	*head;
409 		struct sk_buff	*tail;
410 	} sk_backlog;
411 #define sk_rmem_alloc sk_backlog.rmem_alloc
412 
413 	int			sk_forward_alloc;
414 #ifdef CONFIG_NET_RX_BUSY_POLL
415 	unsigned int		sk_ll_usec;
416 	/* ===== mostly read cache line ===== */
417 	unsigned int		sk_napi_id;
418 #endif
419 	int			sk_rcvbuf;
420 
421 	struct sk_filter __rcu	*sk_filter;
422 	union {
423 		struct socket_wq __rcu	*sk_wq;
424 		/* private: */
425 		struct socket_wq	*sk_wq_raw;
426 		/* public: */
427 	};
428 #ifdef CONFIG_XFRM
429 	struct xfrm_policy __rcu *sk_policy[2];
430 #endif
431 	struct dst_entry	*sk_rx_dst;
432 	struct dst_entry __rcu	*sk_dst_cache;
433 	atomic_t		sk_omem_alloc;
434 	int			sk_sndbuf;
435 
436 	/* ===== cache line for TX ===== */
437 	int			sk_wmem_queued;
438 	refcount_t		sk_wmem_alloc;
439 	unsigned long		sk_tsq_flags;
440 	union {
441 		struct sk_buff	*sk_send_head;
442 		struct rb_root	tcp_rtx_queue;
443 	};
444 	struct sk_buff		*sk_tx_skb_cache;
445 	struct sk_buff_head	sk_write_queue;
446 	__s32			sk_peek_off;
447 	int			sk_write_pending;
448 	__u32			sk_dst_pending_confirm;
449 	u32			sk_pacing_status; /* see enum sk_pacing */
450 	long			sk_sndtimeo;
451 	struct timer_list	sk_timer;
452 	__u32			sk_priority;
453 	__u32			sk_mark;
454 	unsigned long		sk_pacing_rate; /* bytes per second */
455 	unsigned long		sk_max_pacing_rate;
456 	struct page_frag	sk_frag;
457 	netdev_features_t	sk_route_caps;
458 	netdev_features_t	sk_route_nocaps;
459 	netdev_features_t	sk_route_forced_caps;
460 	int			sk_gso_type;
461 	unsigned int		sk_gso_max_size;
462 	gfp_t			sk_allocation;
463 	__u32			sk_txhash;
464 
465 	/*
466 	 * Because of non atomicity rules, all
467 	 * changes are protected by socket lock.
468 	 */
469 	u8			sk_padding : 1,
470 				sk_kern_sock : 1,
471 				sk_no_check_tx : 1,
472 				sk_no_check_rx : 1,
473 				sk_userlocks : 4;
474 	u8			sk_pacing_shift;
475 	u16			sk_type;
476 	u16			sk_protocol;
477 	u16			sk_gso_max_segs;
478 	unsigned long	        sk_lingertime;
479 	struct proto		*sk_prot_creator;
480 	rwlock_t		sk_callback_lock;
481 	int			sk_err,
482 				sk_err_soft;
483 	u32			sk_ack_backlog;
484 	u32			sk_max_ack_backlog;
485 	kuid_t			sk_uid;
486 #ifdef CONFIG_NET_RX_BUSY_POLL
487 	u8			sk_prefer_busy_poll;
488 	u16			sk_busy_poll_budget;
489 #endif
490 	struct pid		*sk_peer_pid;
491 	const struct cred	*sk_peer_cred;
492 	long			sk_rcvtimeo;
493 	ktime_t			sk_stamp;
494 #if BITS_PER_LONG==32
495 	seqlock_t		sk_stamp_seq;
496 #endif
497 	u16			sk_tsflags;
498 	int			sk_bind_phc;
499 	u8			sk_shutdown;
500 	u32			sk_tskey;
501 	atomic_t		sk_zckey;
502 
503 	u8			sk_clockid;
504 	u8			sk_txtime_deadline_mode : 1,
505 				sk_txtime_report_errors : 1,
506 				sk_txtime_unused : 6;
507 
508 	struct socket		*sk_socket;
509 	void			*sk_user_data;
510 #ifdef CONFIG_SECURITY
511 	void			*sk_security;
512 #endif
513 	struct sock_cgroup_data	sk_cgrp_data;
514 	struct mem_cgroup	*sk_memcg;
515 	void			(*sk_state_change)(struct sock *sk);
516 	void			(*sk_data_ready)(struct sock *sk);
517 	void			(*sk_write_space)(struct sock *sk);
518 	void			(*sk_error_report)(struct sock *sk);
519 	int			(*sk_backlog_rcv)(struct sock *sk,
520 						  struct sk_buff *skb);
521 #ifdef CONFIG_SOCK_VALIDATE_XMIT
522 	struct sk_buff*		(*sk_validate_xmit_skb)(struct sock *sk,
523 							struct net_device *dev,
524 							struct sk_buff *skb);
525 #endif
526 	void                    (*sk_destruct)(struct sock *sk);
527 	struct sock_reuseport __rcu	*sk_reuseport_cb;
528 #ifdef CONFIG_BPF_SYSCALL
529 	struct bpf_local_storage __rcu	*sk_bpf_storage;
530 #endif
531 	struct rcu_head		sk_rcu;
532 };
533 
534 enum sk_pacing {
535 	SK_PACING_NONE		= 0,
536 	SK_PACING_NEEDED	= 1,
537 	SK_PACING_FQ		= 2,
538 };
539 
540 /* Pointer stored in sk_user_data might not be suitable for copying
541  * when cloning the socket. For instance, it can point to a reference
542  * counted object. sk_user_data bottom bit is set if pointer must not
543  * be copied.
544  */
545 #define SK_USER_DATA_NOCOPY	1UL
546 #define SK_USER_DATA_BPF	2UL	/* Managed by BPF */
547 #define SK_USER_DATA_PTRMASK	~(SK_USER_DATA_NOCOPY | SK_USER_DATA_BPF)
548 
549 /**
550  * sk_user_data_is_nocopy - Test if sk_user_data pointer must not be copied
551  * @sk: socket
552  */
553 static inline bool sk_user_data_is_nocopy(const struct sock *sk)
554 {
555 	return ((uintptr_t)sk->sk_user_data & SK_USER_DATA_NOCOPY);
556 }
557 
558 #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data)))
559 
560 #define rcu_dereference_sk_user_data(sk)				\
561 ({									\
562 	void *__tmp = rcu_dereference(__sk_user_data((sk)));		\
563 	(void *)((uintptr_t)__tmp & SK_USER_DATA_PTRMASK);		\
564 })
565 #define rcu_assign_sk_user_data(sk, ptr)				\
566 ({									\
567 	uintptr_t __tmp = (uintptr_t)(ptr);				\
568 	WARN_ON_ONCE(__tmp & ~SK_USER_DATA_PTRMASK);			\
569 	rcu_assign_pointer(__sk_user_data((sk)), __tmp);		\
570 })
571 #define rcu_assign_sk_user_data_nocopy(sk, ptr)				\
572 ({									\
573 	uintptr_t __tmp = (uintptr_t)(ptr);				\
574 	WARN_ON_ONCE(__tmp & ~SK_USER_DATA_PTRMASK);			\
575 	rcu_assign_pointer(__sk_user_data((sk)),			\
576 			   __tmp | SK_USER_DATA_NOCOPY);		\
577 })
578 
579 /*
580  * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
581  * or not whether his port will be reused by someone else. SK_FORCE_REUSE
582  * on a socket means that the socket will reuse everybody else's port
583  * without looking at the other's sk_reuse value.
584  */
585 
586 #define SK_NO_REUSE	0
587 #define SK_CAN_REUSE	1
588 #define SK_FORCE_REUSE	2
589 
590 int sk_set_peek_off(struct sock *sk, int val);
591 
592 static inline int sk_peek_offset(struct sock *sk, int flags)
593 {
594 	if (unlikely(flags & MSG_PEEK)) {
595 		return READ_ONCE(sk->sk_peek_off);
596 	}
597 
598 	return 0;
599 }
600 
601 static inline void sk_peek_offset_bwd(struct sock *sk, int val)
602 {
603 	s32 off = READ_ONCE(sk->sk_peek_off);
604 
605 	if (unlikely(off >= 0)) {
606 		off = max_t(s32, off - val, 0);
607 		WRITE_ONCE(sk->sk_peek_off, off);
608 	}
609 }
610 
611 static inline void sk_peek_offset_fwd(struct sock *sk, int val)
612 {
613 	sk_peek_offset_bwd(sk, -val);
614 }
615 
616 /*
617  * Hashed lists helper routines
618  */
619 static inline struct sock *sk_entry(const struct hlist_node *node)
620 {
621 	return hlist_entry(node, struct sock, sk_node);
622 }
623 
624 static inline struct sock *__sk_head(const struct hlist_head *head)
625 {
626 	return hlist_entry(head->first, struct sock, sk_node);
627 }
628 
629 static inline struct sock *sk_head(const struct hlist_head *head)
630 {
631 	return hlist_empty(head) ? NULL : __sk_head(head);
632 }
633 
634 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
635 {
636 	return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
637 }
638 
639 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
640 {
641 	return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
642 }
643 
644 static inline struct sock *sk_next(const struct sock *sk)
645 {
646 	return hlist_entry_safe(sk->sk_node.next, struct sock, sk_node);
647 }
648 
649 static inline struct sock *sk_nulls_next(const struct sock *sk)
650 {
651 	return (!is_a_nulls(sk->sk_nulls_node.next)) ?
652 		hlist_nulls_entry(sk->sk_nulls_node.next,
653 				  struct sock, sk_nulls_node) :
654 		NULL;
655 }
656 
657 static inline bool sk_unhashed(const struct sock *sk)
658 {
659 	return hlist_unhashed(&sk->sk_node);
660 }
661 
662 static inline bool sk_hashed(const struct sock *sk)
663 {
664 	return !sk_unhashed(sk);
665 }
666 
667 static inline void sk_node_init(struct hlist_node *node)
668 {
669 	node->pprev = NULL;
670 }
671 
672 static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
673 {
674 	node->pprev = NULL;
675 }
676 
677 static inline void __sk_del_node(struct sock *sk)
678 {
679 	__hlist_del(&sk->sk_node);
680 }
681 
682 /* NB: equivalent to hlist_del_init_rcu */
683 static inline bool __sk_del_node_init(struct sock *sk)
684 {
685 	if (sk_hashed(sk)) {
686 		__sk_del_node(sk);
687 		sk_node_init(&sk->sk_node);
688 		return true;
689 	}
690 	return false;
691 }
692 
693 /* Grab socket reference count. This operation is valid only
694    when sk is ALREADY grabbed f.e. it is found in hash table
695    or a list and the lookup is made under lock preventing hash table
696    modifications.
697  */
698 
699 static __always_inline void sock_hold(struct sock *sk)
700 {
701 	refcount_inc(&sk->sk_refcnt);
702 }
703 
704 /* Ungrab socket in the context, which assumes that socket refcnt
705    cannot hit zero, f.e. it is true in context of any socketcall.
706  */
707 static __always_inline void __sock_put(struct sock *sk)
708 {
709 	refcount_dec(&sk->sk_refcnt);
710 }
711 
712 static inline bool sk_del_node_init(struct sock *sk)
713 {
714 	bool rc = __sk_del_node_init(sk);
715 
716 	if (rc) {
717 		/* paranoid for a while -acme */
718 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
719 		__sock_put(sk);
720 	}
721 	return rc;
722 }
723 #define sk_del_node_init_rcu(sk)	sk_del_node_init(sk)
724 
725 static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
726 {
727 	if (sk_hashed(sk)) {
728 		hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
729 		return true;
730 	}
731 	return false;
732 }
733 
734 static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
735 {
736 	bool rc = __sk_nulls_del_node_init_rcu(sk);
737 
738 	if (rc) {
739 		/* paranoid for a while -acme */
740 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
741 		__sock_put(sk);
742 	}
743 	return rc;
744 }
745 
746 static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
747 {
748 	hlist_add_head(&sk->sk_node, list);
749 }
750 
751 static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
752 {
753 	sock_hold(sk);
754 	__sk_add_node(sk, list);
755 }
756 
757 static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
758 {
759 	sock_hold(sk);
760 	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
761 	    sk->sk_family == AF_INET6)
762 		hlist_add_tail_rcu(&sk->sk_node, list);
763 	else
764 		hlist_add_head_rcu(&sk->sk_node, list);
765 }
766 
767 static inline void sk_add_node_tail_rcu(struct sock *sk, struct hlist_head *list)
768 {
769 	sock_hold(sk);
770 	hlist_add_tail_rcu(&sk->sk_node, list);
771 }
772 
773 static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
774 {
775 	hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
776 }
777 
778 static inline void __sk_nulls_add_node_tail_rcu(struct sock *sk, struct hlist_nulls_head *list)
779 {
780 	hlist_nulls_add_tail_rcu(&sk->sk_nulls_node, list);
781 }
782 
783 static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
784 {
785 	sock_hold(sk);
786 	__sk_nulls_add_node_rcu(sk, list);
787 }
788 
789 static inline void __sk_del_bind_node(struct sock *sk)
790 {
791 	__hlist_del(&sk->sk_bind_node);
792 }
793 
794 static inline void sk_add_bind_node(struct sock *sk,
795 					struct hlist_head *list)
796 {
797 	hlist_add_head(&sk->sk_bind_node, list);
798 }
799 
800 #define sk_for_each(__sk, list) \
801 	hlist_for_each_entry(__sk, list, sk_node)
802 #define sk_for_each_rcu(__sk, list) \
803 	hlist_for_each_entry_rcu(__sk, list, sk_node)
804 #define sk_nulls_for_each(__sk, node, list) \
805 	hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
806 #define sk_nulls_for_each_rcu(__sk, node, list) \
807 	hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
808 #define sk_for_each_from(__sk) \
809 	hlist_for_each_entry_from(__sk, sk_node)
810 #define sk_nulls_for_each_from(__sk, node) \
811 	if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
812 		hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
813 #define sk_for_each_safe(__sk, tmp, list) \
814 	hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
815 #define sk_for_each_bound(__sk, list) \
816 	hlist_for_each_entry(__sk, list, sk_bind_node)
817 
818 /**
819  * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset
820  * @tpos:	the type * to use as a loop cursor.
821  * @pos:	the &struct hlist_node to use as a loop cursor.
822  * @head:	the head for your list.
823  * @offset:	offset of hlist_node within the struct.
824  *
825  */
826 #define sk_for_each_entry_offset_rcu(tpos, pos, head, offset)		       \
827 	for (pos = rcu_dereference(hlist_first_rcu(head));		       \
828 	     pos != NULL &&						       \
829 		({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \
830 	     pos = rcu_dereference(hlist_next_rcu(pos)))
831 
832 static inline struct user_namespace *sk_user_ns(struct sock *sk)
833 {
834 	/* Careful only use this in a context where these parameters
835 	 * can not change and must all be valid, such as recvmsg from
836 	 * userspace.
837 	 */
838 	return sk->sk_socket->file->f_cred->user_ns;
839 }
840 
841 /* Sock flags */
842 enum sock_flags {
843 	SOCK_DEAD,
844 	SOCK_DONE,
845 	SOCK_URGINLINE,
846 	SOCK_KEEPOPEN,
847 	SOCK_LINGER,
848 	SOCK_DESTROY,
849 	SOCK_BROADCAST,
850 	SOCK_TIMESTAMP,
851 	SOCK_ZAPPED,
852 	SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
853 	SOCK_DBG, /* %SO_DEBUG setting */
854 	SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
855 	SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
856 	SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
857 	SOCK_MEMALLOC, /* VM depends on this socket for swapping */
858 	SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
859 	SOCK_FASYNC, /* fasync() active */
860 	SOCK_RXQ_OVFL,
861 	SOCK_ZEROCOPY, /* buffers from userspace */
862 	SOCK_WIFI_STATUS, /* push wifi status to userspace */
863 	SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
864 		     * Will use last 4 bytes of packet sent from
865 		     * user-space instead.
866 		     */
867 	SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
868 	SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
869 	SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
870 	SOCK_TXTIME,
871 	SOCK_XDP, /* XDP is attached */
872 	SOCK_TSTAMP_NEW, /* Indicates 64 bit timestamps always */
873 };
874 
875 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
876 
877 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
878 {
879 	nsk->sk_flags = osk->sk_flags;
880 }
881 
882 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
883 {
884 	__set_bit(flag, &sk->sk_flags);
885 }
886 
887 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
888 {
889 	__clear_bit(flag, &sk->sk_flags);
890 }
891 
892 static inline void sock_valbool_flag(struct sock *sk, enum sock_flags bit,
893 				     int valbool)
894 {
895 	if (valbool)
896 		sock_set_flag(sk, bit);
897 	else
898 		sock_reset_flag(sk, bit);
899 }
900 
901 static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
902 {
903 	return test_bit(flag, &sk->sk_flags);
904 }
905 
906 #ifdef CONFIG_NET
907 DECLARE_STATIC_KEY_FALSE(memalloc_socks_key);
908 static inline int sk_memalloc_socks(void)
909 {
910 	return static_branch_unlikely(&memalloc_socks_key);
911 }
912 
913 void __receive_sock(struct file *file);
914 #else
915 
916 static inline int sk_memalloc_socks(void)
917 {
918 	return 0;
919 }
920 
921 static inline void __receive_sock(struct file *file)
922 { }
923 #endif
924 
925 static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)
926 {
927 	return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);
928 }
929 
930 static inline void sk_acceptq_removed(struct sock *sk)
931 {
932 	WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog - 1);
933 }
934 
935 static inline void sk_acceptq_added(struct sock *sk)
936 {
937 	WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog + 1);
938 }
939 
940 /* Note: If you think the test should be:
941  *	return READ_ONCE(sk->sk_ack_backlog) >= READ_ONCE(sk->sk_max_ack_backlog);
942  * Then please take a look at commit 64a146513f8f ("[NET]: Revert incorrect accept queue backlog changes.")
943  */
944 static inline bool sk_acceptq_is_full(const struct sock *sk)
945 {
946 	return READ_ONCE(sk->sk_ack_backlog) > READ_ONCE(sk->sk_max_ack_backlog);
947 }
948 
949 /*
950  * Compute minimal free write space needed to queue new packets.
951  */
952 static inline int sk_stream_min_wspace(const struct sock *sk)
953 {
954 	return READ_ONCE(sk->sk_wmem_queued) >> 1;
955 }
956 
957 static inline int sk_stream_wspace(const struct sock *sk)
958 {
959 	return READ_ONCE(sk->sk_sndbuf) - READ_ONCE(sk->sk_wmem_queued);
960 }
961 
962 static inline void sk_wmem_queued_add(struct sock *sk, int val)
963 {
964 	WRITE_ONCE(sk->sk_wmem_queued, sk->sk_wmem_queued + val);
965 }
966 
967 void sk_stream_write_space(struct sock *sk);
968 
969 /* OOB backlog add */
970 static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
971 {
972 	/* dont let skb dst not refcounted, we are going to leave rcu lock */
973 	skb_dst_force(skb);
974 
975 	if (!sk->sk_backlog.tail)
976 		WRITE_ONCE(sk->sk_backlog.head, skb);
977 	else
978 		sk->sk_backlog.tail->next = skb;
979 
980 	WRITE_ONCE(sk->sk_backlog.tail, skb);
981 	skb->next = NULL;
982 }
983 
984 /*
985  * Take into account size of receive queue and backlog queue
986  * Do not take into account this skb truesize,
987  * to allow even a single big packet to come.
988  */
989 static inline bool sk_rcvqueues_full(const struct sock *sk, unsigned int limit)
990 {
991 	unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
992 
993 	return qsize > limit;
994 }
995 
996 /* The per-socket spinlock must be held here. */
997 static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
998 					      unsigned int limit)
999 {
1000 	if (sk_rcvqueues_full(sk, limit))
1001 		return -ENOBUFS;
1002 
1003 	/*
1004 	 * If the skb was allocated from pfmemalloc reserves, only
1005 	 * allow SOCK_MEMALLOC sockets to use it as this socket is
1006 	 * helping free memory
1007 	 */
1008 	if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
1009 		return -ENOMEM;
1010 
1011 	__sk_add_backlog(sk, skb);
1012 	sk->sk_backlog.len += skb->truesize;
1013 	return 0;
1014 }
1015 
1016 int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
1017 
1018 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
1019 {
1020 	if (sk_memalloc_socks() && skb_pfmemalloc(skb))
1021 		return __sk_backlog_rcv(sk, skb);
1022 
1023 	return sk->sk_backlog_rcv(sk, skb);
1024 }
1025 
1026 static inline void sk_incoming_cpu_update(struct sock *sk)
1027 {
1028 	int cpu = raw_smp_processor_id();
1029 
1030 	if (unlikely(READ_ONCE(sk->sk_incoming_cpu) != cpu))
1031 		WRITE_ONCE(sk->sk_incoming_cpu, cpu);
1032 }
1033 
1034 static inline void sock_rps_record_flow_hash(__u32 hash)
1035 {
1036 #ifdef CONFIG_RPS
1037 	struct rps_sock_flow_table *sock_flow_table;
1038 
1039 	rcu_read_lock();
1040 	sock_flow_table = rcu_dereference(rps_sock_flow_table);
1041 	rps_record_sock_flow(sock_flow_table, hash);
1042 	rcu_read_unlock();
1043 #endif
1044 }
1045 
1046 static inline void sock_rps_record_flow(const struct sock *sk)
1047 {
1048 #ifdef CONFIG_RPS
1049 	if (static_branch_unlikely(&rfs_needed)) {
1050 		/* Reading sk->sk_rxhash might incur an expensive cache line
1051 		 * miss.
1052 		 *
1053 		 * TCP_ESTABLISHED does cover almost all states where RFS
1054 		 * might be useful, and is cheaper [1] than testing :
1055 		 *	IPv4: inet_sk(sk)->inet_daddr
1056 		 * 	IPv6: ipv6_addr_any(&sk->sk_v6_daddr)
1057 		 * OR	an additional socket flag
1058 		 * [1] : sk_state and sk_prot are in the same cache line.
1059 		 */
1060 		if (sk->sk_state == TCP_ESTABLISHED)
1061 			sock_rps_record_flow_hash(sk->sk_rxhash);
1062 	}
1063 #endif
1064 }
1065 
1066 static inline void sock_rps_save_rxhash(struct sock *sk,
1067 					const struct sk_buff *skb)
1068 {
1069 #ifdef CONFIG_RPS
1070 	if (unlikely(sk->sk_rxhash != skb->hash))
1071 		sk->sk_rxhash = skb->hash;
1072 #endif
1073 }
1074 
1075 static inline void sock_rps_reset_rxhash(struct sock *sk)
1076 {
1077 #ifdef CONFIG_RPS
1078 	sk->sk_rxhash = 0;
1079 #endif
1080 }
1081 
1082 #define sk_wait_event(__sk, __timeo, __condition, __wait)		\
1083 	({	int __rc;						\
1084 		release_sock(__sk);					\
1085 		__rc = __condition;					\
1086 		if (!__rc) {						\
1087 			*(__timeo) = wait_woken(__wait,			\
1088 						TASK_INTERRUPTIBLE,	\
1089 						*(__timeo));		\
1090 		}							\
1091 		sched_annotate_sleep();					\
1092 		lock_sock(__sk);					\
1093 		__rc = __condition;					\
1094 		__rc;							\
1095 	})
1096 
1097 int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
1098 int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
1099 void sk_stream_wait_close(struct sock *sk, long timeo_p);
1100 int sk_stream_error(struct sock *sk, int flags, int err);
1101 void sk_stream_kill_queues(struct sock *sk);
1102 void sk_set_memalloc(struct sock *sk);
1103 void sk_clear_memalloc(struct sock *sk);
1104 
1105 void __sk_flush_backlog(struct sock *sk);
1106 
1107 static inline bool sk_flush_backlog(struct sock *sk)
1108 {
1109 	if (unlikely(READ_ONCE(sk->sk_backlog.tail))) {
1110 		__sk_flush_backlog(sk);
1111 		return true;
1112 	}
1113 	return false;
1114 }
1115 
1116 int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb);
1117 
1118 struct request_sock_ops;
1119 struct timewait_sock_ops;
1120 struct inet_hashinfo;
1121 struct raw_hashinfo;
1122 struct smc_hashinfo;
1123 struct module;
1124 struct sk_psock;
1125 
1126 /*
1127  * caches using SLAB_TYPESAFE_BY_RCU should let .next pointer from nulls nodes
1128  * un-modified. Special care is taken when initializing object to zero.
1129  */
1130 static inline void sk_prot_clear_nulls(struct sock *sk, int size)
1131 {
1132 	if (offsetof(struct sock, sk_node.next) != 0)
1133 		memset(sk, 0, offsetof(struct sock, sk_node.next));
1134 	memset(&sk->sk_node.pprev, 0,
1135 	       size - offsetof(struct sock, sk_node.pprev));
1136 }
1137 
1138 /* Networking protocol blocks we attach to sockets.
1139  * socket layer -> transport layer interface
1140  */
1141 struct proto {
1142 	void			(*close)(struct sock *sk,
1143 					long timeout);
1144 	int			(*pre_connect)(struct sock *sk,
1145 					struct sockaddr *uaddr,
1146 					int addr_len);
1147 	int			(*connect)(struct sock *sk,
1148 					struct sockaddr *uaddr,
1149 					int addr_len);
1150 	int			(*disconnect)(struct sock *sk, int flags);
1151 
1152 	struct sock *		(*accept)(struct sock *sk, int flags, int *err,
1153 					  bool kern);
1154 
1155 	int			(*ioctl)(struct sock *sk, int cmd,
1156 					 unsigned long arg);
1157 	int			(*init)(struct sock *sk);
1158 	void			(*destroy)(struct sock *sk);
1159 	void			(*shutdown)(struct sock *sk, int how);
1160 	int			(*setsockopt)(struct sock *sk, int level,
1161 					int optname, sockptr_t optval,
1162 					unsigned int optlen);
1163 	int			(*getsockopt)(struct sock *sk, int level,
1164 					int optname, char __user *optval,
1165 					int __user *option);
1166 	void			(*keepalive)(struct sock *sk, int valbool);
1167 #ifdef CONFIG_COMPAT
1168 	int			(*compat_ioctl)(struct sock *sk,
1169 					unsigned int cmd, unsigned long arg);
1170 #endif
1171 	int			(*sendmsg)(struct sock *sk, struct msghdr *msg,
1172 					   size_t len);
1173 	int			(*recvmsg)(struct sock *sk, struct msghdr *msg,
1174 					   size_t len, int noblock, int flags,
1175 					   int *addr_len);
1176 	int			(*sendpage)(struct sock *sk, struct page *page,
1177 					int offset, size_t size, int flags);
1178 	int			(*bind)(struct sock *sk,
1179 					struct sockaddr *addr, int addr_len);
1180 	int			(*bind_add)(struct sock *sk,
1181 					struct sockaddr *addr, int addr_len);
1182 
1183 	int			(*backlog_rcv) (struct sock *sk,
1184 						struct sk_buff *skb);
1185 	bool			(*bpf_bypass_getsockopt)(int level,
1186 							 int optname);
1187 
1188 	void		(*release_cb)(struct sock *sk);
1189 
1190 	/* Keeping track of sk's, looking them up, and port selection methods. */
1191 	int			(*hash)(struct sock *sk);
1192 	void			(*unhash)(struct sock *sk);
1193 	void			(*rehash)(struct sock *sk);
1194 	int			(*get_port)(struct sock *sk, unsigned short snum);
1195 #ifdef CONFIG_BPF_SYSCALL
1196 	int			(*psock_update_sk_prot)(struct sock *sk,
1197 							struct sk_psock *psock,
1198 							bool restore);
1199 #endif
1200 
1201 	/* Keeping track of sockets in use */
1202 #ifdef CONFIG_PROC_FS
1203 	unsigned int		inuse_idx;
1204 #endif
1205 
1206 	bool			(*stream_memory_free)(const struct sock *sk, int wake);
1207 	bool			(*stream_memory_read)(const struct sock *sk);
1208 	/* Memory pressure */
1209 	void			(*enter_memory_pressure)(struct sock *sk);
1210 	void			(*leave_memory_pressure)(struct sock *sk);
1211 	atomic_long_t		*memory_allocated;	/* Current allocated memory. */
1212 	struct percpu_counter	*sockets_allocated;	/* Current number of sockets. */
1213 	/*
1214 	 * Pressure flag: try to collapse.
1215 	 * Technical note: it is used by multiple contexts non atomically.
1216 	 * All the __sk_mem_schedule() is of this nature: accounting
1217 	 * is strict, actions are advisory and have some latency.
1218 	 */
1219 	unsigned long		*memory_pressure;
1220 	long			*sysctl_mem;
1221 
1222 	int			*sysctl_wmem;
1223 	int			*sysctl_rmem;
1224 	u32			sysctl_wmem_offset;
1225 	u32			sysctl_rmem_offset;
1226 
1227 	int			max_header;
1228 	bool			no_autobind;
1229 
1230 	struct kmem_cache	*slab;
1231 	unsigned int		obj_size;
1232 	slab_flags_t		slab_flags;
1233 	unsigned int		useroffset;	/* Usercopy region offset */
1234 	unsigned int		usersize;	/* Usercopy region size */
1235 
1236 	struct percpu_counter	*orphan_count;
1237 
1238 	struct request_sock_ops	*rsk_prot;
1239 	struct timewait_sock_ops *twsk_prot;
1240 
1241 	union {
1242 		struct inet_hashinfo	*hashinfo;
1243 		struct udp_table	*udp_table;
1244 		struct raw_hashinfo	*raw_hash;
1245 		struct smc_hashinfo	*smc_hash;
1246 	} h;
1247 
1248 	struct module		*owner;
1249 
1250 	char			name[32];
1251 
1252 	struct list_head	node;
1253 #ifdef SOCK_REFCNT_DEBUG
1254 	atomic_t		socks;
1255 #endif
1256 	int			(*diag_destroy)(struct sock *sk, int err);
1257 } __randomize_layout;
1258 
1259 int proto_register(struct proto *prot, int alloc_slab);
1260 void proto_unregister(struct proto *prot);
1261 int sock_load_diag_module(int family, int protocol);
1262 
1263 #ifdef SOCK_REFCNT_DEBUG
1264 static inline void sk_refcnt_debug_inc(struct sock *sk)
1265 {
1266 	atomic_inc(&sk->sk_prot->socks);
1267 }
1268 
1269 static inline void sk_refcnt_debug_dec(struct sock *sk)
1270 {
1271 	atomic_dec(&sk->sk_prot->socks);
1272 	printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1273 	       sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1274 }
1275 
1276 static inline void sk_refcnt_debug_release(const struct sock *sk)
1277 {
1278 	if (refcount_read(&sk->sk_refcnt) != 1)
1279 		printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1280 		       sk->sk_prot->name, sk, refcount_read(&sk->sk_refcnt));
1281 }
1282 #else /* SOCK_REFCNT_DEBUG */
1283 #define sk_refcnt_debug_inc(sk) do { } while (0)
1284 #define sk_refcnt_debug_dec(sk) do { } while (0)
1285 #define sk_refcnt_debug_release(sk) do { } while (0)
1286 #endif /* SOCK_REFCNT_DEBUG */
1287 
1288 INDIRECT_CALLABLE_DECLARE(bool tcp_stream_memory_free(const struct sock *sk, int wake));
1289 
1290 static inline bool __sk_stream_memory_free(const struct sock *sk, int wake)
1291 {
1292 	if (READ_ONCE(sk->sk_wmem_queued) >= READ_ONCE(sk->sk_sndbuf))
1293 		return false;
1294 
1295 #ifdef CONFIG_INET
1296 	return sk->sk_prot->stream_memory_free ?
1297 		INDIRECT_CALL_1(sk->sk_prot->stream_memory_free,
1298 			        tcp_stream_memory_free,
1299 				sk, wake) : true;
1300 #else
1301 	return sk->sk_prot->stream_memory_free ?
1302 		sk->sk_prot->stream_memory_free(sk, wake) : true;
1303 #endif
1304 }
1305 
1306 static inline bool sk_stream_memory_free(const struct sock *sk)
1307 {
1308 	return __sk_stream_memory_free(sk, 0);
1309 }
1310 
1311 static inline bool __sk_stream_is_writeable(const struct sock *sk, int wake)
1312 {
1313 	return sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) &&
1314 	       __sk_stream_memory_free(sk, wake);
1315 }
1316 
1317 static inline bool sk_stream_is_writeable(const struct sock *sk)
1318 {
1319 	return __sk_stream_is_writeable(sk, 0);
1320 }
1321 
1322 static inline int sk_under_cgroup_hierarchy(struct sock *sk,
1323 					    struct cgroup *ancestor)
1324 {
1325 #ifdef CONFIG_SOCK_CGROUP_DATA
1326 	return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data),
1327 				    ancestor);
1328 #else
1329 	return -ENOTSUPP;
1330 #endif
1331 }
1332 
1333 static inline bool sk_has_memory_pressure(const struct sock *sk)
1334 {
1335 	return sk->sk_prot->memory_pressure != NULL;
1336 }
1337 
1338 static inline bool sk_under_memory_pressure(const struct sock *sk)
1339 {
1340 	if (!sk->sk_prot->memory_pressure)
1341 		return false;
1342 
1343 	if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
1344 	    mem_cgroup_under_socket_pressure(sk->sk_memcg))
1345 		return true;
1346 
1347 	return !!*sk->sk_prot->memory_pressure;
1348 }
1349 
1350 static inline long
1351 sk_memory_allocated(const struct sock *sk)
1352 {
1353 	return atomic_long_read(sk->sk_prot->memory_allocated);
1354 }
1355 
1356 static inline long
1357 sk_memory_allocated_add(struct sock *sk, int amt)
1358 {
1359 	return atomic_long_add_return(amt, sk->sk_prot->memory_allocated);
1360 }
1361 
1362 static inline void
1363 sk_memory_allocated_sub(struct sock *sk, int amt)
1364 {
1365 	atomic_long_sub(amt, sk->sk_prot->memory_allocated);
1366 }
1367 
1368 #define SK_ALLOC_PERCPU_COUNTER_BATCH 16
1369 
1370 static inline void sk_sockets_allocated_dec(struct sock *sk)
1371 {
1372 	percpu_counter_add_batch(sk->sk_prot->sockets_allocated, -1,
1373 				 SK_ALLOC_PERCPU_COUNTER_BATCH);
1374 }
1375 
1376 static inline void sk_sockets_allocated_inc(struct sock *sk)
1377 {
1378 	percpu_counter_add_batch(sk->sk_prot->sockets_allocated, 1,
1379 				 SK_ALLOC_PERCPU_COUNTER_BATCH);
1380 }
1381 
1382 static inline u64
1383 sk_sockets_allocated_read_positive(struct sock *sk)
1384 {
1385 	return percpu_counter_read_positive(sk->sk_prot->sockets_allocated);
1386 }
1387 
1388 static inline int
1389 proto_sockets_allocated_sum_positive(struct proto *prot)
1390 {
1391 	return percpu_counter_sum_positive(prot->sockets_allocated);
1392 }
1393 
1394 static inline long
1395 proto_memory_allocated(struct proto *prot)
1396 {
1397 	return atomic_long_read(prot->memory_allocated);
1398 }
1399 
1400 static inline bool
1401 proto_memory_pressure(struct proto *prot)
1402 {
1403 	if (!prot->memory_pressure)
1404 		return false;
1405 	return !!*prot->memory_pressure;
1406 }
1407 
1408 
1409 #ifdef CONFIG_PROC_FS
1410 /* Called with local bh disabled */
1411 void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1412 int sock_prot_inuse_get(struct net *net, struct proto *proto);
1413 int sock_inuse_get(struct net *net);
1414 #else
1415 static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1416 		int inc)
1417 {
1418 }
1419 #endif
1420 
1421 
1422 /* With per-bucket locks this operation is not-atomic, so that
1423  * this version is not worse.
1424  */
1425 static inline int __sk_prot_rehash(struct sock *sk)
1426 {
1427 	sk->sk_prot->unhash(sk);
1428 	return sk->sk_prot->hash(sk);
1429 }
1430 
1431 /* About 10 seconds */
1432 #define SOCK_DESTROY_TIME (10*HZ)
1433 
1434 /* Sockets 0-1023 can't be bound to unless you are superuser */
1435 #define PROT_SOCK	1024
1436 
1437 #define SHUTDOWN_MASK	3
1438 #define RCV_SHUTDOWN	1
1439 #define SEND_SHUTDOWN	2
1440 
1441 #define SOCK_SNDBUF_LOCK	1
1442 #define SOCK_RCVBUF_LOCK	2
1443 #define SOCK_BINDADDR_LOCK	4
1444 #define SOCK_BINDPORT_LOCK	8
1445 
1446 struct socket_alloc {
1447 	struct socket socket;
1448 	struct inode vfs_inode;
1449 };
1450 
1451 static inline struct socket *SOCKET_I(struct inode *inode)
1452 {
1453 	return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1454 }
1455 
1456 static inline struct inode *SOCK_INODE(struct socket *socket)
1457 {
1458 	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1459 }
1460 
1461 /*
1462  * Functions for memory accounting
1463  */
1464 int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind);
1465 int __sk_mem_schedule(struct sock *sk, int size, int kind);
1466 void __sk_mem_reduce_allocated(struct sock *sk, int amount);
1467 void __sk_mem_reclaim(struct sock *sk, int amount);
1468 
1469 /* We used to have PAGE_SIZE here, but systems with 64KB pages
1470  * do not necessarily have 16x time more memory than 4KB ones.
1471  */
1472 #define SK_MEM_QUANTUM 4096
1473 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1474 #define SK_MEM_SEND	0
1475 #define SK_MEM_RECV	1
1476 
1477 /* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
1478 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1479 {
1480 	long val = sk->sk_prot->sysctl_mem[index];
1481 
1482 #if PAGE_SIZE > SK_MEM_QUANTUM
1483 	val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
1484 #elif PAGE_SIZE < SK_MEM_QUANTUM
1485 	val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
1486 #endif
1487 	return val;
1488 }
1489 
1490 static inline int sk_mem_pages(int amt)
1491 {
1492 	return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1493 }
1494 
1495 static inline bool sk_has_account(struct sock *sk)
1496 {
1497 	/* return true if protocol supports memory accounting */
1498 	return !!sk->sk_prot->memory_allocated;
1499 }
1500 
1501 static inline bool sk_wmem_schedule(struct sock *sk, int size)
1502 {
1503 	if (!sk_has_account(sk))
1504 		return true;
1505 	return size <= sk->sk_forward_alloc ||
1506 		__sk_mem_schedule(sk, size, SK_MEM_SEND);
1507 }
1508 
1509 static inline bool
1510 sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1511 {
1512 	if (!sk_has_account(sk))
1513 		return true;
1514 	return size <= sk->sk_forward_alloc ||
1515 		__sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1516 		skb_pfmemalloc(skb);
1517 }
1518 
1519 static inline void sk_mem_reclaim(struct sock *sk)
1520 {
1521 	if (!sk_has_account(sk))
1522 		return;
1523 	if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1524 		__sk_mem_reclaim(sk, sk->sk_forward_alloc);
1525 }
1526 
1527 static inline void sk_mem_reclaim_partial(struct sock *sk)
1528 {
1529 	if (!sk_has_account(sk))
1530 		return;
1531 	if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1532 		__sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);
1533 }
1534 
1535 static inline void sk_mem_charge(struct sock *sk, int size)
1536 {
1537 	if (!sk_has_account(sk))
1538 		return;
1539 	sk->sk_forward_alloc -= size;
1540 }
1541 
1542 static inline void sk_mem_uncharge(struct sock *sk, int size)
1543 {
1544 	if (!sk_has_account(sk))
1545 		return;
1546 	sk->sk_forward_alloc += size;
1547 
1548 	/* Avoid a possible overflow.
1549 	 * TCP send queues can make this happen, if sk_mem_reclaim()
1550 	 * is not called and more than 2 GBytes are released at once.
1551 	 *
1552 	 * If we reach 2 MBytes, reclaim 1 MBytes right now, there is
1553 	 * no need to hold that much forward allocation anyway.
1554 	 */
1555 	if (unlikely(sk->sk_forward_alloc >= 1 << 21))
1556 		__sk_mem_reclaim(sk, 1 << 20);
1557 }
1558 
1559 DECLARE_STATIC_KEY_FALSE(tcp_tx_skb_cache_key);
1560 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1561 {
1562 	sk_wmem_queued_add(sk, -skb->truesize);
1563 	sk_mem_uncharge(sk, skb->truesize);
1564 	if (static_branch_unlikely(&tcp_tx_skb_cache_key) &&
1565 	    !sk->sk_tx_skb_cache && !skb_cloned(skb)) {
1566 		skb_ext_reset(skb);
1567 		skb_zcopy_clear(skb, true);
1568 		sk->sk_tx_skb_cache = skb;
1569 		return;
1570 	}
1571 	__kfree_skb(skb);
1572 }
1573 
1574 static inline void sock_release_ownership(struct sock *sk)
1575 {
1576 	if (sk->sk_lock.owned) {
1577 		sk->sk_lock.owned = 0;
1578 
1579 		/* The sk_lock has mutex_unlock() semantics: */
1580 		mutex_release(&sk->sk_lock.dep_map, _RET_IP_);
1581 	}
1582 }
1583 
1584 /*
1585  * Macro so as to not evaluate some arguments when
1586  * lockdep is not enabled.
1587  *
1588  * Mark both the sk_lock and the sk_lock.slock as a
1589  * per-address-family lock class.
1590  */
1591 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)	\
1592 do {									\
1593 	sk->sk_lock.owned = 0;						\
1594 	init_waitqueue_head(&sk->sk_lock.wq);				\
1595 	spin_lock_init(&(sk)->sk_lock.slock);				\
1596 	debug_check_no_locks_freed((void *)&(sk)->sk_lock,		\
1597 			sizeof((sk)->sk_lock));				\
1598 	lockdep_set_class_and_name(&(sk)->sk_lock.slock,		\
1599 				(skey), (sname));				\
1600 	lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);	\
1601 } while (0)
1602 
1603 static inline bool lockdep_sock_is_held(const struct sock *sk)
1604 {
1605 	return lockdep_is_held(&sk->sk_lock) ||
1606 	       lockdep_is_held(&sk->sk_lock.slock);
1607 }
1608 
1609 void lock_sock_nested(struct sock *sk, int subclass);
1610 
1611 static inline void lock_sock(struct sock *sk)
1612 {
1613 	lock_sock_nested(sk, 0);
1614 }
1615 
1616 void __lock_sock(struct sock *sk);
1617 void __release_sock(struct sock *sk);
1618 void release_sock(struct sock *sk);
1619 
1620 /* BH context may only use the following locking interface. */
1621 #define bh_lock_sock(__sk)	spin_lock(&((__sk)->sk_lock.slock))
1622 #define bh_lock_sock_nested(__sk) \
1623 				spin_lock_nested(&((__sk)->sk_lock.slock), \
1624 				SINGLE_DEPTH_NESTING)
1625 #define bh_unlock_sock(__sk)	spin_unlock(&((__sk)->sk_lock.slock))
1626 
1627 bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock);
1628 
1629 /**
1630  * unlock_sock_fast - complement of lock_sock_fast
1631  * @sk: socket
1632  * @slow: slow mode
1633  *
1634  * fast unlock socket for user context.
1635  * If slow mode is on, we call regular release_sock()
1636  */
1637 static inline void unlock_sock_fast(struct sock *sk, bool slow)
1638 	__releases(&sk->sk_lock.slock)
1639 {
1640 	if (slow) {
1641 		release_sock(sk);
1642 		__release(&sk->sk_lock.slock);
1643 	} else {
1644 		spin_unlock_bh(&sk->sk_lock.slock);
1645 	}
1646 }
1647 
1648 /* Used by processes to "lock" a socket state, so that
1649  * interrupts and bottom half handlers won't change it
1650  * from under us. It essentially blocks any incoming
1651  * packets, so that we won't get any new data or any
1652  * packets that change the state of the socket.
1653  *
1654  * While locked, BH processing will add new packets to
1655  * the backlog queue.  This queue is processed by the
1656  * owner of the socket lock right before it is released.
1657  *
1658  * Since ~2.3.5 it is also exclusive sleep lock serializing
1659  * accesses from user process context.
1660  */
1661 
1662 static inline void sock_owned_by_me(const struct sock *sk)
1663 {
1664 #ifdef CONFIG_LOCKDEP
1665 	WARN_ON_ONCE(!lockdep_sock_is_held(sk) && debug_locks);
1666 #endif
1667 }
1668 
1669 static inline bool sock_owned_by_user(const struct sock *sk)
1670 {
1671 	sock_owned_by_me(sk);
1672 	return sk->sk_lock.owned;
1673 }
1674 
1675 static inline bool sock_owned_by_user_nocheck(const struct sock *sk)
1676 {
1677 	return sk->sk_lock.owned;
1678 }
1679 
1680 /* no reclassification while locks are held */
1681 static inline bool sock_allow_reclassification(const struct sock *csk)
1682 {
1683 	struct sock *sk = (struct sock *)csk;
1684 
1685 	return !sk->sk_lock.owned && !spin_is_locked(&sk->sk_lock.slock);
1686 }
1687 
1688 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
1689 		      struct proto *prot, int kern);
1690 void sk_free(struct sock *sk);
1691 void sk_destruct(struct sock *sk);
1692 struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority);
1693 void sk_free_unlock_clone(struct sock *sk);
1694 
1695 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
1696 			     gfp_t priority);
1697 void __sock_wfree(struct sk_buff *skb);
1698 void sock_wfree(struct sk_buff *skb);
1699 struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size,
1700 			     gfp_t priority);
1701 void skb_orphan_partial(struct sk_buff *skb);
1702 void sock_rfree(struct sk_buff *skb);
1703 void sock_efree(struct sk_buff *skb);
1704 #ifdef CONFIG_INET
1705 void sock_edemux(struct sk_buff *skb);
1706 void sock_pfree(struct sk_buff *skb);
1707 #else
1708 #define sock_edemux sock_efree
1709 #endif
1710 
1711 int sock_setsockopt(struct socket *sock, int level, int op,
1712 		    sockptr_t optval, unsigned int optlen);
1713 
1714 int sock_getsockopt(struct socket *sock, int level, int op,
1715 		    char __user *optval, int __user *optlen);
1716 int sock_gettstamp(struct socket *sock, void __user *userstamp,
1717 		   bool timeval, bool time32);
1718 struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
1719 				    int noblock, int *errcode);
1720 struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
1721 				     unsigned long data_len, int noblock,
1722 				     int *errcode, int max_page_order);
1723 void *sock_kmalloc(struct sock *sk, int size, gfp_t priority);
1724 void sock_kfree_s(struct sock *sk, void *mem, int size);
1725 void sock_kzfree_s(struct sock *sk, void *mem, int size);
1726 void sk_send_sigurg(struct sock *sk);
1727 
1728 struct sockcm_cookie {
1729 	u64 transmit_time;
1730 	u32 mark;
1731 	u16 tsflags;
1732 };
1733 
1734 static inline void sockcm_init(struct sockcm_cookie *sockc,
1735 			       const struct sock *sk)
1736 {
1737 	*sockc = (struct sockcm_cookie) { .tsflags = sk->sk_tsflags };
1738 }
1739 
1740 int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
1741 		     struct sockcm_cookie *sockc);
1742 int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
1743 		   struct sockcm_cookie *sockc);
1744 
1745 /*
1746  * Functions to fill in entries in struct proto_ops when a protocol
1747  * does not implement a particular function.
1748  */
1749 int sock_no_bind(struct socket *, struct sockaddr *, int);
1750 int sock_no_connect(struct socket *, struct sockaddr *, int, int);
1751 int sock_no_socketpair(struct socket *, struct socket *);
1752 int sock_no_accept(struct socket *, struct socket *, int, bool);
1753 int sock_no_getname(struct socket *, struct sockaddr *, int);
1754 int sock_no_ioctl(struct socket *, unsigned int, unsigned long);
1755 int sock_no_listen(struct socket *, int);
1756 int sock_no_shutdown(struct socket *, int);
1757 int sock_no_sendmsg(struct socket *, struct msghdr *, size_t);
1758 int sock_no_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t len);
1759 int sock_no_recvmsg(struct socket *, struct msghdr *, size_t, int);
1760 int sock_no_mmap(struct file *file, struct socket *sock,
1761 		 struct vm_area_struct *vma);
1762 ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset,
1763 			 size_t size, int flags);
1764 ssize_t sock_no_sendpage_locked(struct sock *sk, struct page *page,
1765 				int offset, size_t size, int flags);
1766 
1767 /*
1768  * Functions to fill in entries in struct proto_ops when a protocol
1769  * uses the inet style.
1770  */
1771 int sock_common_getsockopt(struct socket *sock, int level, int optname,
1772 				  char __user *optval, int __user *optlen);
1773 int sock_common_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1774 			int flags);
1775 int sock_common_setsockopt(struct socket *sock, int level, int optname,
1776 			   sockptr_t optval, unsigned int optlen);
1777 
1778 void sk_common_release(struct sock *sk);
1779 
1780 /*
1781  *	Default socket callbacks and setup code
1782  */
1783 
1784 /* Initialise core socket variables */
1785 void sock_init_data(struct socket *sock, struct sock *sk);
1786 
1787 /*
1788  * Socket reference counting postulates.
1789  *
1790  * * Each user of socket SHOULD hold a reference count.
1791  * * Each access point to socket (an hash table bucket, reference from a list,
1792  *   running timer, skb in flight MUST hold a reference count.
1793  * * When reference count hits 0, it means it will never increase back.
1794  * * When reference count hits 0, it means that no references from
1795  *   outside exist to this socket and current process on current CPU
1796  *   is last user and may/should destroy this socket.
1797  * * sk_free is called from any context: process, BH, IRQ. When
1798  *   it is called, socket has no references from outside -> sk_free
1799  *   may release descendant resources allocated by the socket, but
1800  *   to the time when it is called, socket is NOT referenced by any
1801  *   hash tables, lists etc.
1802  * * Packets, delivered from outside (from network or from another process)
1803  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1804  *   when they sit in queue. Otherwise, packets will leak to hole, when
1805  *   socket is looked up by one cpu and unhasing is made by another CPU.
1806  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1807  *   (leak to backlog). Packet socket does all the processing inside
1808  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1809  *   use separate SMP lock, so that they are prone too.
1810  */
1811 
1812 /* Ungrab socket and destroy it, if it was the last reference. */
1813 static inline void sock_put(struct sock *sk)
1814 {
1815 	if (refcount_dec_and_test(&sk->sk_refcnt))
1816 		sk_free(sk);
1817 }
1818 /* Generic version of sock_put(), dealing with all sockets
1819  * (TCP_TIMEWAIT, TCP_NEW_SYN_RECV, ESTABLISHED...)
1820  */
1821 void sock_gen_put(struct sock *sk);
1822 
1823 int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested,
1824 		     unsigned int trim_cap, bool refcounted);
1825 static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1826 				 const int nested)
1827 {
1828 	return __sk_receive_skb(sk, skb, nested, 1, true);
1829 }
1830 
1831 static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
1832 {
1833 	/* sk_tx_queue_mapping accept only upto a 16-bit value */
1834 	if (WARN_ON_ONCE((unsigned short)tx_queue >= USHRT_MAX))
1835 		return;
1836 	sk->sk_tx_queue_mapping = tx_queue;
1837 }
1838 
1839 #define NO_QUEUE_MAPPING	USHRT_MAX
1840 
1841 static inline void sk_tx_queue_clear(struct sock *sk)
1842 {
1843 	sk->sk_tx_queue_mapping = NO_QUEUE_MAPPING;
1844 }
1845 
1846 static inline int sk_tx_queue_get(const struct sock *sk)
1847 {
1848 	if (sk && sk->sk_tx_queue_mapping != NO_QUEUE_MAPPING)
1849 		return sk->sk_tx_queue_mapping;
1850 
1851 	return -1;
1852 }
1853 
1854 static inline void sk_rx_queue_set(struct sock *sk, const struct sk_buff *skb)
1855 {
1856 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
1857 	if (skb_rx_queue_recorded(skb)) {
1858 		u16 rx_queue = skb_get_rx_queue(skb);
1859 
1860 		if (WARN_ON_ONCE(rx_queue == NO_QUEUE_MAPPING))
1861 			return;
1862 
1863 		sk->sk_rx_queue_mapping = rx_queue;
1864 	}
1865 #endif
1866 }
1867 
1868 static inline void sk_rx_queue_clear(struct sock *sk)
1869 {
1870 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
1871 	sk->sk_rx_queue_mapping = NO_QUEUE_MAPPING;
1872 #endif
1873 }
1874 
1875 static inline int sk_rx_queue_get(const struct sock *sk)
1876 {
1877 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
1878 	if (sk && sk->sk_rx_queue_mapping != NO_QUEUE_MAPPING)
1879 		return sk->sk_rx_queue_mapping;
1880 #endif
1881 
1882 	return -1;
1883 }
1884 
1885 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1886 {
1887 	sk->sk_socket = sock;
1888 }
1889 
1890 static inline wait_queue_head_t *sk_sleep(struct sock *sk)
1891 {
1892 	BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
1893 	return &rcu_dereference_raw(sk->sk_wq)->wait;
1894 }
1895 /* Detach socket from process context.
1896  * Announce socket dead, detach it from wait queue and inode.
1897  * Note that parent inode held reference count on this struct sock,
1898  * we do not release it in this function, because protocol
1899  * probably wants some additional cleanups or even continuing
1900  * to work with this socket (TCP).
1901  */
1902 static inline void sock_orphan(struct sock *sk)
1903 {
1904 	write_lock_bh(&sk->sk_callback_lock);
1905 	sock_set_flag(sk, SOCK_DEAD);
1906 	sk_set_socket(sk, NULL);
1907 	sk->sk_wq  = NULL;
1908 	write_unlock_bh(&sk->sk_callback_lock);
1909 }
1910 
1911 static inline void sock_graft(struct sock *sk, struct socket *parent)
1912 {
1913 	WARN_ON(parent->sk);
1914 	write_lock_bh(&sk->sk_callback_lock);
1915 	rcu_assign_pointer(sk->sk_wq, &parent->wq);
1916 	parent->sk = sk;
1917 	sk_set_socket(sk, parent);
1918 	sk->sk_uid = SOCK_INODE(parent)->i_uid;
1919 	security_sock_graft(sk, parent);
1920 	write_unlock_bh(&sk->sk_callback_lock);
1921 }
1922 
1923 kuid_t sock_i_uid(struct sock *sk);
1924 unsigned long sock_i_ino(struct sock *sk);
1925 
1926 static inline kuid_t sock_net_uid(const struct net *net, const struct sock *sk)
1927 {
1928 	return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
1929 }
1930 
1931 static inline u32 net_tx_rndhash(void)
1932 {
1933 	u32 v = prandom_u32();
1934 
1935 	return v ?: 1;
1936 }
1937 
1938 static inline void sk_set_txhash(struct sock *sk)
1939 {
1940 	/* This pairs with READ_ONCE() in skb_set_hash_from_sk() */
1941 	WRITE_ONCE(sk->sk_txhash, net_tx_rndhash());
1942 }
1943 
1944 static inline bool sk_rethink_txhash(struct sock *sk)
1945 {
1946 	if (sk->sk_txhash) {
1947 		sk_set_txhash(sk);
1948 		return true;
1949 	}
1950 	return false;
1951 }
1952 
1953 static inline struct dst_entry *
1954 __sk_dst_get(struct sock *sk)
1955 {
1956 	return rcu_dereference_check(sk->sk_dst_cache,
1957 				     lockdep_sock_is_held(sk));
1958 }
1959 
1960 static inline struct dst_entry *
1961 sk_dst_get(struct sock *sk)
1962 {
1963 	struct dst_entry *dst;
1964 
1965 	rcu_read_lock();
1966 	dst = rcu_dereference(sk->sk_dst_cache);
1967 	if (dst && !atomic_inc_not_zero(&dst->__refcnt))
1968 		dst = NULL;
1969 	rcu_read_unlock();
1970 	return dst;
1971 }
1972 
1973 static inline void __dst_negative_advice(struct sock *sk)
1974 {
1975 	struct dst_entry *ndst, *dst = __sk_dst_get(sk);
1976 
1977 	if (dst && dst->ops->negative_advice) {
1978 		ndst = dst->ops->negative_advice(dst);
1979 
1980 		if (ndst != dst) {
1981 			rcu_assign_pointer(sk->sk_dst_cache, ndst);
1982 			sk_tx_queue_clear(sk);
1983 			sk->sk_dst_pending_confirm = 0;
1984 		}
1985 	}
1986 }
1987 
1988 static inline void dst_negative_advice(struct sock *sk)
1989 {
1990 	sk_rethink_txhash(sk);
1991 	__dst_negative_advice(sk);
1992 }
1993 
1994 static inline void
1995 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1996 {
1997 	struct dst_entry *old_dst;
1998 
1999 	sk_tx_queue_clear(sk);
2000 	sk->sk_dst_pending_confirm = 0;
2001 	old_dst = rcu_dereference_protected(sk->sk_dst_cache,
2002 					    lockdep_sock_is_held(sk));
2003 	rcu_assign_pointer(sk->sk_dst_cache, dst);
2004 	dst_release(old_dst);
2005 }
2006 
2007 static inline void
2008 sk_dst_set(struct sock *sk, struct dst_entry *dst)
2009 {
2010 	struct dst_entry *old_dst;
2011 
2012 	sk_tx_queue_clear(sk);
2013 	sk->sk_dst_pending_confirm = 0;
2014 	old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
2015 	dst_release(old_dst);
2016 }
2017 
2018 static inline void
2019 __sk_dst_reset(struct sock *sk)
2020 {
2021 	__sk_dst_set(sk, NULL);
2022 }
2023 
2024 static inline void
2025 sk_dst_reset(struct sock *sk)
2026 {
2027 	sk_dst_set(sk, NULL);
2028 }
2029 
2030 struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
2031 
2032 struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
2033 
2034 static inline void sk_dst_confirm(struct sock *sk)
2035 {
2036 	if (!READ_ONCE(sk->sk_dst_pending_confirm))
2037 		WRITE_ONCE(sk->sk_dst_pending_confirm, 1);
2038 }
2039 
2040 static inline void sock_confirm_neigh(struct sk_buff *skb, struct neighbour *n)
2041 {
2042 	if (skb_get_dst_pending_confirm(skb)) {
2043 		struct sock *sk = skb->sk;
2044 		unsigned long now = jiffies;
2045 
2046 		/* avoid dirtying neighbour */
2047 		if (READ_ONCE(n->confirmed) != now)
2048 			WRITE_ONCE(n->confirmed, now);
2049 		if (sk && READ_ONCE(sk->sk_dst_pending_confirm))
2050 			WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
2051 	}
2052 }
2053 
2054 bool sk_mc_loop(struct sock *sk);
2055 
2056 static inline bool sk_can_gso(const struct sock *sk)
2057 {
2058 	return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
2059 }
2060 
2061 void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
2062 
2063 static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
2064 {
2065 	sk->sk_route_nocaps |= flags;
2066 	sk->sk_route_caps &= ~flags;
2067 }
2068 
2069 static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
2070 					   struct iov_iter *from, char *to,
2071 					   int copy, int offset)
2072 {
2073 	if (skb->ip_summed == CHECKSUM_NONE) {
2074 		__wsum csum = 0;
2075 		if (!csum_and_copy_from_iter_full(to, copy, &csum, from))
2076 			return -EFAULT;
2077 		skb->csum = csum_block_add(skb->csum, csum, offset);
2078 	} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
2079 		if (!copy_from_iter_full_nocache(to, copy, from))
2080 			return -EFAULT;
2081 	} else if (!copy_from_iter_full(to, copy, from))
2082 		return -EFAULT;
2083 
2084 	return 0;
2085 }
2086 
2087 static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
2088 				       struct iov_iter *from, int copy)
2089 {
2090 	int err, offset = skb->len;
2091 
2092 	err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
2093 				       copy, offset);
2094 	if (err)
2095 		__skb_trim(skb, offset);
2096 
2097 	return err;
2098 }
2099 
2100 static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *from,
2101 					   struct sk_buff *skb,
2102 					   struct page *page,
2103 					   int off, int copy)
2104 {
2105 	int err;
2106 
2107 	err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
2108 				       copy, skb->len);
2109 	if (err)
2110 		return err;
2111 
2112 	skb->len	     += copy;
2113 	skb->data_len	     += copy;
2114 	skb->truesize	     += copy;
2115 	sk_wmem_queued_add(sk, copy);
2116 	sk_mem_charge(sk, copy);
2117 	return 0;
2118 }
2119 
2120 /**
2121  * sk_wmem_alloc_get - returns write allocations
2122  * @sk: socket
2123  *
2124  * Return: sk_wmem_alloc minus initial offset of one
2125  */
2126 static inline int sk_wmem_alloc_get(const struct sock *sk)
2127 {
2128 	return refcount_read(&sk->sk_wmem_alloc) - 1;
2129 }
2130 
2131 /**
2132  * sk_rmem_alloc_get - returns read allocations
2133  * @sk: socket
2134  *
2135  * Return: sk_rmem_alloc
2136  */
2137 static inline int sk_rmem_alloc_get(const struct sock *sk)
2138 {
2139 	return atomic_read(&sk->sk_rmem_alloc);
2140 }
2141 
2142 /**
2143  * sk_has_allocations - check if allocations are outstanding
2144  * @sk: socket
2145  *
2146  * Return: true if socket has write or read allocations
2147  */
2148 static inline bool sk_has_allocations(const struct sock *sk)
2149 {
2150 	return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
2151 }
2152 
2153 /**
2154  * skwq_has_sleeper - check if there are any waiting processes
2155  * @wq: struct socket_wq
2156  *
2157  * Return: true if socket_wq has waiting processes
2158  *
2159  * The purpose of the skwq_has_sleeper and sock_poll_wait is to wrap the memory
2160  * barrier call. They were added due to the race found within the tcp code.
2161  *
2162  * Consider following tcp code paths::
2163  *
2164  *   CPU1                CPU2
2165  *   sys_select          receive packet
2166  *   ...                 ...
2167  *   __add_wait_queue    update tp->rcv_nxt
2168  *   ...                 ...
2169  *   tp->rcv_nxt check   sock_def_readable
2170  *   ...                 {
2171  *   schedule               rcu_read_lock();
2172  *                          wq = rcu_dereference(sk->sk_wq);
2173  *                          if (wq && waitqueue_active(&wq->wait))
2174  *                              wake_up_interruptible(&wq->wait)
2175  *                          ...
2176  *                       }
2177  *
2178  * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
2179  * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
2180  * could then endup calling schedule and sleep forever if there are no more
2181  * data on the socket.
2182  *
2183  */
2184 static inline bool skwq_has_sleeper(struct socket_wq *wq)
2185 {
2186 	return wq && wq_has_sleeper(&wq->wait);
2187 }
2188 
2189 /**
2190  * sock_poll_wait - place memory barrier behind the poll_wait call.
2191  * @filp:           file
2192  * @sock:           socket to wait on
2193  * @p:              poll_table
2194  *
2195  * See the comments in the wq_has_sleeper function.
2196  */
2197 static inline void sock_poll_wait(struct file *filp, struct socket *sock,
2198 				  poll_table *p)
2199 {
2200 	if (!poll_does_not_wait(p)) {
2201 		poll_wait(filp, &sock->wq.wait, p);
2202 		/* We need to be sure we are in sync with the
2203 		 * socket flags modification.
2204 		 *
2205 		 * This memory barrier is paired in the wq_has_sleeper.
2206 		 */
2207 		smp_mb();
2208 	}
2209 }
2210 
2211 static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)
2212 {
2213 	/* This pairs with WRITE_ONCE() in sk_set_txhash() */
2214 	u32 txhash = READ_ONCE(sk->sk_txhash);
2215 
2216 	if (txhash) {
2217 		skb->l4_hash = 1;
2218 		skb->hash = txhash;
2219 	}
2220 }
2221 
2222 void skb_set_owner_w(struct sk_buff *skb, struct sock *sk);
2223 
2224 /*
2225  *	Queue a received datagram if it will fit. Stream and sequenced
2226  *	protocols can't normally use this as they need to fit buffers in
2227  *	and play with them.
2228  *
2229  *	Inlined as it's very short and called for pretty much every
2230  *	packet ever received.
2231  */
2232 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
2233 {
2234 	skb_orphan(skb);
2235 	skb->sk = sk;
2236 	skb->destructor = sock_rfree;
2237 	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
2238 	sk_mem_charge(sk, skb->truesize);
2239 }
2240 
2241 static inline __must_check bool skb_set_owner_sk_safe(struct sk_buff *skb, struct sock *sk)
2242 {
2243 	if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) {
2244 		skb_orphan(skb);
2245 		skb->destructor = sock_efree;
2246 		skb->sk = sk;
2247 		return true;
2248 	}
2249 	return false;
2250 }
2251 
2252 static inline void skb_prepare_for_gro(struct sk_buff *skb)
2253 {
2254 	if (skb->destructor != sock_wfree) {
2255 		skb_orphan(skb);
2256 		return;
2257 	}
2258 	skb->slow_gro = 1;
2259 }
2260 
2261 void sk_reset_timer(struct sock *sk, struct timer_list *timer,
2262 		    unsigned long expires);
2263 
2264 void sk_stop_timer(struct sock *sk, struct timer_list *timer);
2265 
2266 void sk_stop_timer_sync(struct sock *sk, struct timer_list *timer);
2267 
2268 int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue,
2269 			struct sk_buff *skb, unsigned int flags,
2270 			void (*destructor)(struct sock *sk,
2271 					   struct sk_buff *skb));
2272 int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2273 int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2274 
2275 int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
2276 struct sk_buff *sock_dequeue_err_skb(struct sock *sk);
2277 
2278 /*
2279  *	Recover an error report and clear atomically
2280  */
2281 
2282 static inline int sock_error(struct sock *sk)
2283 {
2284 	int err;
2285 
2286 	/* Avoid an atomic operation for the common case.
2287 	 * This is racy since another cpu/thread can change sk_err under us.
2288 	 */
2289 	if (likely(data_race(!sk->sk_err)))
2290 		return 0;
2291 
2292 	err = xchg(&sk->sk_err, 0);
2293 	return -err;
2294 }
2295 
2296 void sk_error_report(struct sock *sk);
2297 
2298 static inline unsigned long sock_wspace(struct sock *sk)
2299 {
2300 	int amt = 0;
2301 
2302 	if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
2303 		amt = sk->sk_sndbuf - refcount_read(&sk->sk_wmem_alloc);
2304 		if (amt < 0)
2305 			amt = 0;
2306 	}
2307 	return amt;
2308 }
2309 
2310 /* Note:
2311  *  We use sk->sk_wq_raw, from contexts knowing this
2312  *  pointer is not NULL and cannot disappear/change.
2313  */
2314 static inline void sk_set_bit(int nr, struct sock *sk)
2315 {
2316 	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2317 	    !sock_flag(sk, SOCK_FASYNC))
2318 		return;
2319 
2320 	set_bit(nr, &sk->sk_wq_raw->flags);
2321 }
2322 
2323 static inline void sk_clear_bit(int nr, struct sock *sk)
2324 {
2325 	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2326 	    !sock_flag(sk, SOCK_FASYNC))
2327 		return;
2328 
2329 	clear_bit(nr, &sk->sk_wq_raw->flags);
2330 }
2331 
2332 static inline void sk_wake_async(const struct sock *sk, int how, int band)
2333 {
2334 	if (sock_flag(sk, SOCK_FASYNC)) {
2335 		rcu_read_lock();
2336 		sock_wake_async(rcu_dereference(sk->sk_wq), how, band);
2337 		rcu_read_unlock();
2338 	}
2339 }
2340 
2341 /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
2342  * need sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak.
2343  * Note: for send buffers, TCP works better if we can build two skbs at
2344  * minimum.
2345  */
2346 #define TCP_SKB_MIN_TRUESIZE	(2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
2347 
2348 #define SOCK_MIN_SNDBUF		(TCP_SKB_MIN_TRUESIZE * 2)
2349 #define SOCK_MIN_RCVBUF		 TCP_SKB_MIN_TRUESIZE
2350 
2351 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
2352 {
2353 	u32 val;
2354 
2355 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
2356 		return;
2357 
2358 	val = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
2359 
2360 	WRITE_ONCE(sk->sk_sndbuf, max_t(u32, val, SOCK_MIN_SNDBUF));
2361 }
2362 
2363 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
2364 				    bool force_schedule);
2365 
2366 /**
2367  * sk_page_frag - return an appropriate page_frag
2368  * @sk: socket
2369  *
2370  * Use the per task page_frag instead of the per socket one for
2371  * optimization when we know that we're in the normal context and owns
2372  * everything that's associated with %current.
2373  *
2374  * gfpflags_allow_blocking() isn't enough here as direct reclaim may nest
2375  * inside other socket operations and end up recursing into sk_page_frag()
2376  * while it's already in use.
2377  *
2378  * Return: a per task page_frag if context allows that,
2379  * otherwise a per socket one.
2380  */
2381 static inline struct page_frag *sk_page_frag(struct sock *sk)
2382 {
2383 	if (gfpflags_normal_context(sk->sk_allocation))
2384 		return &current->task_frag;
2385 
2386 	return &sk->sk_frag;
2387 }
2388 
2389 bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
2390 
2391 /*
2392  *	Default write policy as shown to user space via poll/select/SIGIO
2393  */
2394 static inline bool sock_writeable(const struct sock *sk)
2395 {
2396 	return refcount_read(&sk->sk_wmem_alloc) < (READ_ONCE(sk->sk_sndbuf) >> 1);
2397 }
2398 
2399 static inline gfp_t gfp_any(void)
2400 {
2401 	return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
2402 }
2403 
2404 static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2405 {
2406 	return noblock ? 0 : sk->sk_rcvtimeo;
2407 }
2408 
2409 static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2410 {
2411 	return noblock ? 0 : sk->sk_sndtimeo;
2412 }
2413 
2414 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2415 {
2416 	int v = waitall ? len : min_t(int, READ_ONCE(sk->sk_rcvlowat), len);
2417 
2418 	return v ?: 1;
2419 }
2420 
2421 /* Alas, with timeout socket operations are not restartable.
2422  * Compare this to poll().
2423  */
2424 static inline int sock_intr_errno(long timeo)
2425 {
2426 	return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2427 }
2428 
2429 struct sock_skb_cb {
2430 	u32 dropcount;
2431 };
2432 
2433 /* Store sock_skb_cb at the end of skb->cb[] so protocol families
2434  * using skb->cb[] would keep using it directly and utilize its
2435  * alignement guarantee.
2436  */
2437 #define SOCK_SKB_CB_OFFSET ((sizeof_field(struct sk_buff, cb) - \
2438 			    sizeof(struct sock_skb_cb)))
2439 
2440 #define SOCK_SKB_CB(__skb) ((struct sock_skb_cb *)((__skb)->cb + \
2441 			    SOCK_SKB_CB_OFFSET))
2442 
2443 #define sock_skb_cb_check_size(size) \
2444 	BUILD_BUG_ON((size) > SOCK_SKB_CB_OFFSET)
2445 
2446 static inline void
2447 sock_skb_set_dropcount(const struct sock *sk, struct sk_buff *skb)
2448 {
2449 	SOCK_SKB_CB(skb)->dropcount = sock_flag(sk, SOCK_RXQ_OVFL) ?
2450 						atomic_read(&sk->sk_drops) : 0;
2451 }
2452 
2453 static inline void sk_drops_add(struct sock *sk, const struct sk_buff *skb)
2454 {
2455 	int segs = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
2456 
2457 	atomic_add(segs, &sk->sk_drops);
2458 }
2459 
2460 static inline ktime_t sock_read_timestamp(struct sock *sk)
2461 {
2462 #if BITS_PER_LONG==32
2463 	unsigned int seq;
2464 	ktime_t kt;
2465 
2466 	do {
2467 		seq = read_seqbegin(&sk->sk_stamp_seq);
2468 		kt = sk->sk_stamp;
2469 	} while (read_seqretry(&sk->sk_stamp_seq, seq));
2470 
2471 	return kt;
2472 #else
2473 	return READ_ONCE(sk->sk_stamp);
2474 #endif
2475 }
2476 
2477 static inline void sock_write_timestamp(struct sock *sk, ktime_t kt)
2478 {
2479 #if BITS_PER_LONG==32
2480 	write_seqlock(&sk->sk_stamp_seq);
2481 	sk->sk_stamp = kt;
2482 	write_sequnlock(&sk->sk_stamp_seq);
2483 #else
2484 	WRITE_ONCE(sk->sk_stamp, kt);
2485 #endif
2486 }
2487 
2488 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2489 			   struct sk_buff *skb);
2490 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2491 			     struct sk_buff *skb);
2492 
2493 static inline void
2494 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2495 {
2496 	ktime_t kt = skb->tstamp;
2497 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2498 
2499 	/*
2500 	 * generate control messages if
2501 	 * - receive time stamping in software requested
2502 	 * - software time stamp available and wanted
2503 	 * - hardware time stamps available and wanted
2504 	 */
2505 	if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2506 	    (sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
2507 	    (kt && sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
2508 	    (hwtstamps->hwtstamp &&
2509 	     (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
2510 		__sock_recv_timestamp(msg, sk, skb);
2511 	else
2512 		sock_write_timestamp(sk, kt);
2513 
2514 	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2515 		__sock_recv_wifi_status(msg, sk, skb);
2516 }
2517 
2518 void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2519 			      struct sk_buff *skb);
2520 
2521 #define SK_DEFAULT_STAMP (-1L * NSEC_PER_SEC)
2522 static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2523 					  struct sk_buff *skb)
2524 {
2525 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)			| \
2526 			   (1UL << SOCK_RCVTSTAMP))
2527 #define TSFLAGS_ANY	  (SOF_TIMESTAMPING_SOFTWARE			| \
2528 			   SOF_TIMESTAMPING_RAW_HARDWARE)
2529 
2530 	if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY)
2531 		__sock_recv_ts_and_drops(msg, sk, skb);
2532 	else if (unlikely(sock_flag(sk, SOCK_TIMESTAMP)))
2533 		sock_write_timestamp(sk, skb->tstamp);
2534 	else if (unlikely(sk->sk_stamp == SK_DEFAULT_STAMP))
2535 		sock_write_timestamp(sk, 0);
2536 }
2537 
2538 void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags);
2539 
2540 /**
2541  * _sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2542  * @sk:		socket sending this packet
2543  * @tsflags:	timestamping flags to use
2544  * @tx_flags:	completed with instructions for time stamping
2545  * @tskey:      filled in with next sk_tskey (not for TCP, which uses seqno)
2546  *
2547  * Note: callers should take care of initial ``*tx_flags`` value (usually 0)
2548  */
2549 static inline void _sock_tx_timestamp(struct sock *sk, __u16 tsflags,
2550 				      __u8 *tx_flags, __u32 *tskey)
2551 {
2552 	if (unlikely(tsflags)) {
2553 		__sock_tx_timestamp(tsflags, tx_flags);
2554 		if (tsflags & SOF_TIMESTAMPING_OPT_ID && tskey &&
2555 		    tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
2556 			*tskey = sk->sk_tskey++;
2557 	}
2558 	if (unlikely(sock_flag(sk, SOCK_WIFI_STATUS)))
2559 		*tx_flags |= SKBTX_WIFI_STATUS;
2560 }
2561 
2562 static inline void sock_tx_timestamp(struct sock *sk, __u16 tsflags,
2563 				     __u8 *tx_flags)
2564 {
2565 	_sock_tx_timestamp(sk, tsflags, tx_flags, NULL);
2566 }
2567 
2568 static inline void skb_setup_tx_timestamp(struct sk_buff *skb, __u16 tsflags)
2569 {
2570 	_sock_tx_timestamp(skb->sk, tsflags, &skb_shinfo(skb)->tx_flags,
2571 			   &skb_shinfo(skb)->tskey);
2572 }
2573 
2574 DECLARE_STATIC_KEY_FALSE(tcp_rx_skb_cache_key);
2575 /**
2576  * sk_eat_skb - Release a skb if it is no longer needed
2577  * @sk: socket to eat this skb from
2578  * @skb: socket buffer to eat
2579  *
2580  * This routine must be called with interrupts disabled or with the socket
2581  * locked so that the sk_buff queue operation is ok.
2582 */
2583 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb)
2584 {
2585 	__skb_unlink(skb, &sk->sk_receive_queue);
2586 	if (static_branch_unlikely(&tcp_rx_skb_cache_key) &&
2587 	    !sk->sk_rx_skb_cache) {
2588 		sk->sk_rx_skb_cache = skb;
2589 		skb_orphan(skb);
2590 		return;
2591 	}
2592 	__kfree_skb(skb);
2593 }
2594 
2595 static inline
2596 struct net *sock_net(const struct sock *sk)
2597 {
2598 	return read_pnet(&sk->sk_net);
2599 }
2600 
2601 static inline
2602 void sock_net_set(struct sock *sk, struct net *net)
2603 {
2604 	write_pnet(&sk->sk_net, net);
2605 }
2606 
2607 static inline bool
2608 skb_sk_is_prefetched(struct sk_buff *skb)
2609 {
2610 #ifdef CONFIG_INET
2611 	return skb->destructor == sock_pfree;
2612 #else
2613 	return false;
2614 #endif /* CONFIG_INET */
2615 }
2616 
2617 /* This helper checks if a socket is a full socket,
2618  * ie _not_ a timewait or request socket.
2619  */
2620 static inline bool sk_fullsock(const struct sock *sk)
2621 {
2622 	return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
2623 }
2624 
2625 static inline bool
2626 sk_is_refcounted(struct sock *sk)
2627 {
2628 	/* Only full sockets have sk->sk_flags. */
2629 	return !sk_fullsock(sk) || !sock_flag(sk, SOCK_RCU_FREE);
2630 }
2631 
2632 /**
2633  * skb_steal_sock - steal a socket from an sk_buff
2634  * @skb: sk_buff to steal the socket from
2635  * @refcounted: is set to true if the socket is reference-counted
2636  */
2637 static inline struct sock *
2638 skb_steal_sock(struct sk_buff *skb, bool *refcounted)
2639 {
2640 	if (skb->sk) {
2641 		struct sock *sk = skb->sk;
2642 
2643 		*refcounted = true;
2644 		if (skb_sk_is_prefetched(skb))
2645 			*refcounted = sk_is_refcounted(sk);
2646 		skb->destructor = NULL;
2647 		skb->sk = NULL;
2648 		return sk;
2649 	}
2650 	*refcounted = false;
2651 	return NULL;
2652 }
2653 
2654 /* Checks if this SKB belongs to an HW offloaded socket
2655  * and whether any SW fallbacks are required based on dev.
2656  * Check decrypted mark in case skb_orphan() cleared socket.
2657  */
2658 static inline struct sk_buff *sk_validate_xmit_skb(struct sk_buff *skb,
2659 						   struct net_device *dev)
2660 {
2661 #ifdef CONFIG_SOCK_VALIDATE_XMIT
2662 	struct sock *sk = skb->sk;
2663 
2664 	if (sk && sk_fullsock(sk) && sk->sk_validate_xmit_skb) {
2665 		skb = sk->sk_validate_xmit_skb(sk, dev, skb);
2666 #ifdef CONFIG_TLS_DEVICE
2667 	} else if (unlikely(skb->decrypted)) {
2668 		pr_warn_ratelimited("unencrypted skb with no associated socket - dropping\n");
2669 		kfree_skb(skb);
2670 		skb = NULL;
2671 #endif
2672 	}
2673 #endif
2674 
2675 	return skb;
2676 }
2677 
2678 /* This helper checks if a socket is a LISTEN or NEW_SYN_RECV
2679  * SYNACK messages can be attached to either ones (depending on SYNCOOKIE)
2680  */
2681 static inline bool sk_listener(const struct sock *sk)
2682 {
2683 	return (1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV);
2684 }
2685 
2686 void sock_enable_timestamp(struct sock *sk, enum sock_flags flag);
2687 int sock_recv_errqueue(struct sock *sk, struct msghdr *msg, int len, int level,
2688 		       int type);
2689 
2690 bool sk_ns_capable(const struct sock *sk,
2691 		   struct user_namespace *user_ns, int cap);
2692 bool sk_capable(const struct sock *sk, int cap);
2693 bool sk_net_capable(const struct sock *sk, int cap);
2694 
2695 void sk_get_meminfo(const struct sock *sk, u32 *meminfo);
2696 
2697 /* Take into consideration the size of the struct sk_buff overhead in the
2698  * determination of these values, since that is non-constant across
2699  * platforms.  This makes socket queueing behavior and performance
2700  * not depend upon such differences.
2701  */
2702 #define _SK_MEM_PACKETS		256
2703 #define _SK_MEM_OVERHEAD	SKB_TRUESIZE(256)
2704 #define SK_WMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2705 #define SK_RMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2706 
2707 extern __u32 sysctl_wmem_max;
2708 extern __u32 sysctl_rmem_max;
2709 
2710 extern int sysctl_tstamp_allow_data;
2711 extern int sysctl_optmem_max;
2712 
2713 extern __u32 sysctl_wmem_default;
2714 extern __u32 sysctl_rmem_default;
2715 
2716 DECLARE_STATIC_KEY_FALSE(net_high_order_alloc_disable_key);
2717 
2718 static inline int sk_get_wmem0(const struct sock *sk, const struct proto *proto)
2719 {
2720 	/* Does this proto have per netns sysctl_wmem ? */
2721 	if (proto->sysctl_wmem_offset)
2722 		return *(int *)((void *)sock_net(sk) + proto->sysctl_wmem_offset);
2723 
2724 	return *proto->sysctl_wmem;
2725 }
2726 
2727 static inline int sk_get_rmem0(const struct sock *sk, const struct proto *proto)
2728 {
2729 	/* Does this proto have per netns sysctl_rmem ? */
2730 	if (proto->sysctl_rmem_offset)
2731 		return *(int *)((void *)sock_net(sk) + proto->sysctl_rmem_offset);
2732 
2733 	return *proto->sysctl_rmem;
2734 }
2735 
2736 /* Default TCP Small queue budget is ~1 ms of data (1sec >> 10)
2737  * Some wifi drivers need to tweak it to get more chunks.
2738  * They can use this helper from their ndo_start_xmit()
2739  */
2740 static inline void sk_pacing_shift_update(struct sock *sk, int val)
2741 {
2742 	if (!sk || !sk_fullsock(sk) || READ_ONCE(sk->sk_pacing_shift) == val)
2743 		return;
2744 	WRITE_ONCE(sk->sk_pacing_shift, val);
2745 }
2746 
2747 /* if a socket is bound to a device, check that the given device
2748  * index is either the same or that the socket is bound to an L3
2749  * master device and the given device index is also enslaved to
2750  * that L3 master
2751  */
2752 static inline bool sk_dev_equal_l3scope(struct sock *sk, int dif)
2753 {
2754 	int mdif;
2755 
2756 	if (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif)
2757 		return true;
2758 
2759 	mdif = l3mdev_master_ifindex_by_index(sock_net(sk), dif);
2760 	if (mdif && mdif == sk->sk_bound_dev_if)
2761 		return true;
2762 
2763 	return false;
2764 }
2765 
2766 void sock_def_readable(struct sock *sk);
2767 
2768 int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk);
2769 void sock_set_timestamp(struct sock *sk, int optname, bool valbool);
2770 int sock_set_timestamping(struct sock *sk, int optname,
2771 			  struct so_timestamping timestamping);
2772 
2773 void sock_enable_timestamps(struct sock *sk);
2774 void sock_no_linger(struct sock *sk);
2775 void sock_set_keepalive(struct sock *sk);
2776 void sock_set_priority(struct sock *sk, u32 priority);
2777 void sock_set_rcvbuf(struct sock *sk, int val);
2778 void sock_set_mark(struct sock *sk, u32 val);
2779 void sock_set_reuseaddr(struct sock *sk);
2780 void sock_set_reuseport(struct sock *sk);
2781 void sock_set_sndtimeo(struct sock *sk, s64 secs);
2782 
2783 int sock_bind_add(struct sock *sk, struct sockaddr *addr, int addr_len);
2784 
2785 #endif	/* _SOCK_H */
2786