xref: /openbmc/linux/include/net/sock.h (revision e15a5365)
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 
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_XPS
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_priority: %SO_PRIORITY setting
305   *	@sk_type: socket type (%SOCK_STREAM, etc)
306   *	@sk_protocol: which protocol this socket belongs in this network family
307   *	@sk_peer_pid: &struct pid for this socket's peer
308   *	@sk_peer_cred: %SO_PEERCRED setting
309   *	@sk_rcvlowat: %SO_RCVLOWAT setting
310   *	@sk_rcvtimeo: %SO_RCVTIMEO setting
311   *	@sk_sndtimeo: %SO_SNDTIMEO setting
312   *	@sk_txhash: computed flow hash for use on transmit
313   *	@sk_filter: socket filtering instructions
314   *	@sk_timer: sock cleanup timer
315   *	@sk_stamp: time stamp of last packet received
316   *	@sk_stamp_seq: lock for accessing sk_stamp on 32 bit architectures only
317   *	@sk_tsflags: SO_TIMESTAMPING socket options
318   *	@sk_tskey: counter to disambiguate concurrent tstamp requests
319   *	@sk_zckey: counter to order MSG_ZEROCOPY notifications
320   *	@sk_socket: Identd and reporting IO signals
321   *	@sk_user_data: RPC layer private data
322   *	@sk_frag: cached page frag
323   *	@sk_peek_off: current peek_offset value
324   *	@sk_send_head: front of stuff to transmit
325   *	@tcp_rtx_queue: TCP re-transmit queue [union with @sk_send_head]
326   *	@sk_tx_skb_cache: cache copy of recently accessed TX skb
327   *	@sk_security: used by security modules
328   *	@sk_mark: generic packet mark
329   *	@sk_cgrp_data: cgroup data for this cgroup
330   *	@sk_memcg: this socket's memory cgroup association
331   *	@sk_write_pending: a write to stream socket waits to start
332   *	@sk_state_change: callback to indicate change in the state of the sock
333   *	@sk_data_ready: callback to indicate there is data to be processed
334   *	@sk_write_space: callback to indicate there is bf sending space available
335   *	@sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
336   *	@sk_backlog_rcv: callback to process the backlog
337   *	@sk_validate_xmit_skb: ptr to an optional validate function
338   *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
339   *	@sk_reuseport_cb: reuseport group container
340   *	@sk_bpf_storage: ptr to cache and control for bpf_sk_storage
341   *	@sk_rcu: used during RCU grace period
342   *	@sk_clockid: clockid used by time-based scheduling (SO_TXTIME)
343   *	@sk_txtime_deadline_mode: set deadline mode for SO_TXTIME
344   *	@sk_txtime_report_errors: set report errors mode for SO_TXTIME
345   *	@sk_txtime_unused: unused txtime flags
346   */
347 struct sock {
348 	/*
349 	 * Now struct inet_timewait_sock also uses sock_common, so please just
350 	 * don't add nothing before this first member (__sk_common) --acme
351 	 */
352 	struct sock_common	__sk_common;
353 #define sk_node			__sk_common.skc_node
354 #define sk_nulls_node		__sk_common.skc_nulls_node
355 #define sk_refcnt		__sk_common.skc_refcnt
356 #define sk_tx_queue_mapping	__sk_common.skc_tx_queue_mapping
357 #ifdef CONFIG_XPS
358 #define sk_rx_queue_mapping	__sk_common.skc_rx_queue_mapping
359 #endif
360 
361 #define sk_dontcopy_begin	__sk_common.skc_dontcopy_begin
362 #define sk_dontcopy_end		__sk_common.skc_dontcopy_end
363 #define sk_hash			__sk_common.skc_hash
364 #define sk_portpair		__sk_common.skc_portpair
365 #define sk_num			__sk_common.skc_num
366 #define sk_dport		__sk_common.skc_dport
367 #define sk_addrpair		__sk_common.skc_addrpair
368 #define sk_daddr		__sk_common.skc_daddr
369 #define sk_rcv_saddr		__sk_common.skc_rcv_saddr
370 #define sk_family		__sk_common.skc_family
371 #define sk_state		__sk_common.skc_state
372 #define sk_reuse		__sk_common.skc_reuse
373 #define sk_reuseport		__sk_common.skc_reuseport
374 #define sk_ipv6only		__sk_common.skc_ipv6only
375 #define sk_net_refcnt		__sk_common.skc_net_refcnt
376 #define sk_bound_dev_if		__sk_common.skc_bound_dev_if
377 #define sk_bind_node		__sk_common.skc_bind_node
378 #define sk_prot			__sk_common.skc_prot
379 #define sk_net			__sk_common.skc_net
380 #define sk_v6_daddr		__sk_common.skc_v6_daddr
381 #define sk_v6_rcv_saddr	__sk_common.skc_v6_rcv_saddr
382 #define sk_cookie		__sk_common.skc_cookie
383 #define sk_incoming_cpu		__sk_common.skc_incoming_cpu
384 #define sk_flags		__sk_common.skc_flags
385 #define sk_rxhash		__sk_common.skc_rxhash
386 
387 	socket_lock_t		sk_lock;
388 	atomic_t		sk_drops;
389 	int			sk_rcvlowat;
390 	struct sk_buff_head	sk_error_queue;
391 	struct sk_buff		*sk_rx_skb_cache;
392 	struct sk_buff_head	sk_receive_queue;
393 	/*
394 	 * The backlog queue is special, it is always used with
395 	 * the per-socket spinlock held and requires low latency
396 	 * access. Therefore we special case it's implementation.
397 	 * Note : rmem_alloc is in this structure to fill a hole
398 	 * on 64bit arches, not because its logically part of
399 	 * backlog.
400 	 */
401 	struct {
402 		atomic_t	rmem_alloc;
403 		int		len;
404 		struct sk_buff	*head;
405 		struct sk_buff	*tail;
406 	} sk_backlog;
407 #define sk_rmem_alloc sk_backlog.rmem_alloc
408 
409 	int			sk_forward_alloc;
410 #ifdef CONFIG_NET_RX_BUSY_POLL
411 	unsigned int		sk_ll_usec;
412 	/* ===== mostly read cache line ===== */
413 	unsigned int		sk_napi_id;
414 #endif
415 	int			sk_rcvbuf;
416 
417 	struct sk_filter __rcu	*sk_filter;
418 	union {
419 		struct socket_wq __rcu	*sk_wq;
420 		/* private: */
421 		struct socket_wq	*sk_wq_raw;
422 		/* public: */
423 	};
424 #ifdef CONFIG_XFRM
425 	struct xfrm_policy __rcu *sk_policy[2];
426 #endif
427 	struct dst_entry	*sk_rx_dst;
428 	struct dst_entry __rcu	*sk_dst_cache;
429 	atomic_t		sk_omem_alloc;
430 	int			sk_sndbuf;
431 
432 	/* ===== cache line for TX ===== */
433 	int			sk_wmem_queued;
434 	refcount_t		sk_wmem_alloc;
435 	unsigned long		sk_tsq_flags;
436 	union {
437 		struct sk_buff	*sk_send_head;
438 		struct rb_root	tcp_rtx_queue;
439 	};
440 	struct sk_buff		*sk_tx_skb_cache;
441 	struct sk_buff_head	sk_write_queue;
442 	__s32			sk_peek_off;
443 	int			sk_write_pending;
444 	__u32			sk_dst_pending_confirm;
445 	u32			sk_pacing_status; /* see enum sk_pacing */
446 	long			sk_sndtimeo;
447 	struct timer_list	sk_timer;
448 	__u32			sk_priority;
449 	__u32			sk_mark;
450 	unsigned long		sk_pacing_rate; /* bytes per second */
451 	unsigned long		sk_max_pacing_rate;
452 	struct page_frag	sk_frag;
453 	netdev_features_t	sk_route_caps;
454 	netdev_features_t	sk_route_nocaps;
455 	netdev_features_t	sk_route_forced_caps;
456 	int			sk_gso_type;
457 	unsigned int		sk_gso_max_size;
458 	gfp_t			sk_allocation;
459 	__u32			sk_txhash;
460 
461 	/*
462 	 * Because of non atomicity rules, all
463 	 * changes are protected by socket lock.
464 	 */
465 	u8			sk_padding : 1,
466 				sk_kern_sock : 1,
467 				sk_no_check_tx : 1,
468 				sk_no_check_rx : 1,
469 				sk_userlocks : 4;
470 	u8			sk_pacing_shift;
471 	u16			sk_type;
472 	u16			sk_protocol;
473 	u16			sk_gso_max_segs;
474 	unsigned long	        sk_lingertime;
475 	struct proto		*sk_prot_creator;
476 	rwlock_t		sk_callback_lock;
477 	int			sk_err,
478 				sk_err_soft;
479 	u32			sk_ack_backlog;
480 	u32			sk_max_ack_backlog;
481 	kuid_t			sk_uid;
482 	struct pid		*sk_peer_pid;
483 	const struct cred	*sk_peer_cred;
484 	long			sk_rcvtimeo;
485 	ktime_t			sk_stamp;
486 #if BITS_PER_LONG==32
487 	seqlock_t		sk_stamp_seq;
488 #endif
489 	u16			sk_tsflags;
490 	u8			sk_shutdown;
491 	u32			sk_tskey;
492 	atomic_t		sk_zckey;
493 
494 	u8			sk_clockid;
495 	u8			sk_txtime_deadline_mode : 1,
496 				sk_txtime_report_errors : 1,
497 				sk_txtime_unused : 6;
498 
499 	struct socket		*sk_socket;
500 	void			*sk_user_data;
501 #ifdef CONFIG_SECURITY
502 	void			*sk_security;
503 #endif
504 	struct sock_cgroup_data	sk_cgrp_data;
505 	struct mem_cgroup	*sk_memcg;
506 	void			(*sk_state_change)(struct sock *sk);
507 	void			(*sk_data_ready)(struct sock *sk);
508 	void			(*sk_write_space)(struct sock *sk);
509 	void			(*sk_error_report)(struct sock *sk);
510 	int			(*sk_backlog_rcv)(struct sock *sk,
511 						  struct sk_buff *skb);
512 #ifdef CONFIG_SOCK_VALIDATE_XMIT
513 	struct sk_buff*		(*sk_validate_xmit_skb)(struct sock *sk,
514 							struct net_device *dev,
515 							struct sk_buff *skb);
516 #endif
517 	void                    (*sk_destruct)(struct sock *sk);
518 	struct sock_reuseport __rcu	*sk_reuseport_cb;
519 #ifdef CONFIG_BPF_SYSCALL
520 	struct bpf_local_storage __rcu	*sk_bpf_storage;
521 #endif
522 	struct rcu_head		sk_rcu;
523 };
524 
525 enum sk_pacing {
526 	SK_PACING_NONE		= 0,
527 	SK_PACING_NEEDED	= 1,
528 	SK_PACING_FQ		= 2,
529 };
530 
531 /* Pointer stored in sk_user_data might not be suitable for copying
532  * when cloning the socket. For instance, it can point to a reference
533  * counted object. sk_user_data bottom bit is set if pointer must not
534  * be copied.
535  */
536 #define SK_USER_DATA_NOCOPY	1UL
537 #define SK_USER_DATA_BPF	2UL	/* Managed by BPF */
538 #define SK_USER_DATA_PTRMASK	~(SK_USER_DATA_NOCOPY | SK_USER_DATA_BPF)
539 
540 /**
541  * sk_user_data_is_nocopy - Test if sk_user_data pointer must not be copied
542  * @sk: socket
543  */
544 static inline bool sk_user_data_is_nocopy(const struct sock *sk)
545 {
546 	return ((uintptr_t)sk->sk_user_data & SK_USER_DATA_NOCOPY);
547 }
548 
549 #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data)))
550 
551 #define rcu_dereference_sk_user_data(sk)				\
552 ({									\
553 	void *__tmp = rcu_dereference(__sk_user_data((sk)));		\
554 	(void *)((uintptr_t)__tmp & SK_USER_DATA_PTRMASK);		\
555 })
556 #define rcu_assign_sk_user_data(sk, ptr)				\
557 ({									\
558 	uintptr_t __tmp = (uintptr_t)(ptr);				\
559 	WARN_ON_ONCE(__tmp & ~SK_USER_DATA_PTRMASK);			\
560 	rcu_assign_pointer(__sk_user_data((sk)), __tmp);		\
561 })
562 #define rcu_assign_sk_user_data_nocopy(sk, ptr)				\
563 ({									\
564 	uintptr_t __tmp = (uintptr_t)(ptr);				\
565 	WARN_ON_ONCE(__tmp & ~SK_USER_DATA_PTRMASK);			\
566 	rcu_assign_pointer(__sk_user_data((sk)),			\
567 			   __tmp | SK_USER_DATA_NOCOPY);		\
568 })
569 
570 /*
571  * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
572  * or not whether his port will be reused by someone else. SK_FORCE_REUSE
573  * on a socket means that the socket will reuse everybody else's port
574  * without looking at the other's sk_reuse value.
575  */
576 
577 #define SK_NO_REUSE	0
578 #define SK_CAN_REUSE	1
579 #define SK_FORCE_REUSE	2
580 
581 int sk_set_peek_off(struct sock *sk, int val);
582 
583 static inline int sk_peek_offset(struct sock *sk, int flags)
584 {
585 	if (unlikely(flags & MSG_PEEK)) {
586 		return READ_ONCE(sk->sk_peek_off);
587 	}
588 
589 	return 0;
590 }
591 
592 static inline void sk_peek_offset_bwd(struct sock *sk, int val)
593 {
594 	s32 off = READ_ONCE(sk->sk_peek_off);
595 
596 	if (unlikely(off >= 0)) {
597 		off = max_t(s32, off - val, 0);
598 		WRITE_ONCE(sk->sk_peek_off, off);
599 	}
600 }
601 
602 static inline void sk_peek_offset_fwd(struct sock *sk, int val)
603 {
604 	sk_peek_offset_bwd(sk, -val);
605 }
606 
607 /*
608  * Hashed lists helper routines
609  */
610 static inline struct sock *sk_entry(const struct hlist_node *node)
611 {
612 	return hlist_entry(node, struct sock, sk_node);
613 }
614 
615 static inline struct sock *__sk_head(const struct hlist_head *head)
616 {
617 	return hlist_entry(head->first, struct sock, sk_node);
618 }
619 
620 static inline struct sock *sk_head(const struct hlist_head *head)
621 {
622 	return hlist_empty(head) ? NULL : __sk_head(head);
623 }
624 
625 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
626 {
627 	return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
628 }
629 
630 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
631 {
632 	return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
633 }
634 
635 static inline struct sock *sk_next(const struct sock *sk)
636 {
637 	return hlist_entry_safe(sk->sk_node.next, struct sock, sk_node);
638 }
639 
640 static inline struct sock *sk_nulls_next(const struct sock *sk)
641 {
642 	return (!is_a_nulls(sk->sk_nulls_node.next)) ?
643 		hlist_nulls_entry(sk->sk_nulls_node.next,
644 				  struct sock, sk_nulls_node) :
645 		NULL;
646 }
647 
648 static inline bool sk_unhashed(const struct sock *sk)
649 {
650 	return hlist_unhashed(&sk->sk_node);
651 }
652 
653 static inline bool sk_hashed(const struct sock *sk)
654 {
655 	return !sk_unhashed(sk);
656 }
657 
658 static inline void sk_node_init(struct hlist_node *node)
659 {
660 	node->pprev = NULL;
661 }
662 
663 static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
664 {
665 	node->pprev = NULL;
666 }
667 
668 static inline void __sk_del_node(struct sock *sk)
669 {
670 	__hlist_del(&sk->sk_node);
671 }
672 
673 /* NB: equivalent to hlist_del_init_rcu */
674 static inline bool __sk_del_node_init(struct sock *sk)
675 {
676 	if (sk_hashed(sk)) {
677 		__sk_del_node(sk);
678 		sk_node_init(&sk->sk_node);
679 		return true;
680 	}
681 	return false;
682 }
683 
684 /* Grab socket reference count. This operation is valid only
685    when sk is ALREADY grabbed f.e. it is found in hash table
686    or a list and the lookup is made under lock preventing hash table
687    modifications.
688  */
689 
690 static __always_inline void sock_hold(struct sock *sk)
691 {
692 	refcount_inc(&sk->sk_refcnt);
693 }
694 
695 /* Ungrab socket in the context, which assumes that socket refcnt
696    cannot hit zero, f.e. it is true in context of any socketcall.
697  */
698 static __always_inline void __sock_put(struct sock *sk)
699 {
700 	refcount_dec(&sk->sk_refcnt);
701 }
702 
703 static inline bool sk_del_node_init(struct sock *sk)
704 {
705 	bool rc = __sk_del_node_init(sk);
706 
707 	if (rc) {
708 		/* paranoid for a while -acme */
709 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
710 		__sock_put(sk);
711 	}
712 	return rc;
713 }
714 #define sk_del_node_init_rcu(sk)	sk_del_node_init(sk)
715 
716 static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
717 {
718 	if (sk_hashed(sk)) {
719 		hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
720 		return true;
721 	}
722 	return false;
723 }
724 
725 static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
726 {
727 	bool rc = __sk_nulls_del_node_init_rcu(sk);
728 
729 	if (rc) {
730 		/* paranoid for a while -acme */
731 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
732 		__sock_put(sk);
733 	}
734 	return rc;
735 }
736 
737 static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
738 {
739 	hlist_add_head(&sk->sk_node, list);
740 }
741 
742 static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
743 {
744 	sock_hold(sk);
745 	__sk_add_node(sk, list);
746 }
747 
748 static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
749 {
750 	sock_hold(sk);
751 	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
752 	    sk->sk_family == AF_INET6)
753 		hlist_add_tail_rcu(&sk->sk_node, list);
754 	else
755 		hlist_add_head_rcu(&sk->sk_node, list);
756 }
757 
758 static inline void sk_add_node_tail_rcu(struct sock *sk, struct hlist_head *list)
759 {
760 	sock_hold(sk);
761 	hlist_add_tail_rcu(&sk->sk_node, list);
762 }
763 
764 static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
765 {
766 	hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
767 }
768 
769 static inline void __sk_nulls_add_node_tail_rcu(struct sock *sk, struct hlist_nulls_head *list)
770 {
771 	hlist_nulls_add_tail_rcu(&sk->sk_nulls_node, list);
772 }
773 
774 static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
775 {
776 	sock_hold(sk);
777 	__sk_nulls_add_node_rcu(sk, list);
778 }
779 
780 static inline void __sk_del_bind_node(struct sock *sk)
781 {
782 	__hlist_del(&sk->sk_bind_node);
783 }
784 
785 static inline void sk_add_bind_node(struct sock *sk,
786 					struct hlist_head *list)
787 {
788 	hlist_add_head(&sk->sk_bind_node, list);
789 }
790 
791 #define sk_for_each(__sk, list) \
792 	hlist_for_each_entry(__sk, list, sk_node)
793 #define sk_for_each_rcu(__sk, list) \
794 	hlist_for_each_entry_rcu(__sk, list, sk_node)
795 #define sk_nulls_for_each(__sk, node, list) \
796 	hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
797 #define sk_nulls_for_each_rcu(__sk, node, list) \
798 	hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
799 #define sk_for_each_from(__sk) \
800 	hlist_for_each_entry_from(__sk, sk_node)
801 #define sk_nulls_for_each_from(__sk, node) \
802 	if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
803 		hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
804 #define sk_for_each_safe(__sk, tmp, list) \
805 	hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
806 #define sk_for_each_bound(__sk, list) \
807 	hlist_for_each_entry(__sk, list, sk_bind_node)
808 
809 /**
810  * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset
811  * @tpos:	the type * to use as a loop cursor.
812  * @pos:	the &struct hlist_node to use as a loop cursor.
813  * @head:	the head for your list.
814  * @offset:	offset of hlist_node within the struct.
815  *
816  */
817 #define sk_for_each_entry_offset_rcu(tpos, pos, head, offset)		       \
818 	for (pos = rcu_dereference(hlist_first_rcu(head));		       \
819 	     pos != NULL &&						       \
820 		({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \
821 	     pos = rcu_dereference(hlist_next_rcu(pos)))
822 
823 static inline struct user_namespace *sk_user_ns(struct sock *sk)
824 {
825 	/* Careful only use this in a context where these parameters
826 	 * can not change and must all be valid, such as recvmsg from
827 	 * userspace.
828 	 */
829 	return sk->sk_socket->file->f_cred->user_ns;
830 }
831 
832 /* Sock flags */
833 enum sock_flags {
834 	SOCK_DEAD,
835 	SOCK_DONE,
836 	SOCK_URGINLINE,
837 	SOCK_KEEPOPEN,
838 	SOCK_LINGER,
839 	SOCK_DESTROY,
840 	SOCK_BROADCAST,
841 	SOCK_TIMESTAMP,
842 	SOCK_ZAPPED,
843 	SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
844 	SOCK_DBG, /* %SO_DEBUG setting */
845 	SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
846 	SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
847 	SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
848 	SOCK_MEMALLOC, /* VM depends on this socket for swapping */
849 	SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
850 	SOCK_FASYNC, /* fasync() active */
851 	SOCK_RXQ_OVFL,
852 	SOCK_ZEROCOPY, /* buffers from userspace */
853 	SOCK_WIFI_STATUS, /* push wifi status to userspace */
854 	SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
855 		     * Will use last 4 bytes of packet sent from
856 		     * user-space instead.
857 		     */
858 	SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
859 	SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
860 	SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
861 	SOCK_TXTIME,
862 	SOCK_XDP, /* XDP is attached */
863 	SOCK_TSTAMP_NEW, /* Indicates 64 bit timestamps always */
864 };
865 
866 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
867 
868 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
869 {
870 	nsk->sk_flags = osk->sk_flags;
871 }
872 
873 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
874 {
875 	__set_bit(flag, &sk->sk_flags);
876 }
877 
878 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
879 {
880 	__clear_bit(flag, &sk->sk_flags);
881 }
882 
883 static inline void sock_valbool_flag(struct sock *sk, enum sock_flags bit,
884 				     int valbool)
885 {
886 	if (valbool)
887 		sock_set_flag(sk, bit);
888 	else
889 		sock_reset_flag(sk, bit);
890 }
891 
892 static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
893 {
894 	return test_bit(flag, &sk->sk_flags);
895 }
896 
897 #ifdef CONFIG_NET
898 DECLARE_STATIC_KEY_FALSE(memalloc_socks_key);
899 static inline int sk_memalloc_socks(void)
900 {
901 	return static_branch_unlikely(&memalloc_socks_key);
902 }
903 
904 void __receive_sock(struct file *file);
905 #else
906 
907 static inline int sk_memalloc_socks(void)
908 {
909 	return 0;
910 }
911 
912 static inline void __receive_sock(struct file *file)
913 { }
914 #endif
915 
916 static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)
917 {
918 	return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);
919 }
920 
921 static inline void sk_acceptq_removed(struct sock *sk)
922 {
923 	WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog - 1);
924 }
925 
926 static inline void sk_acceptq_added(struct sock *sk)
927 {
928 	WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog + 1);
929 }
930 
931 static inline bool sk_acceptq_is_full(const struct sock *sk)
932 {
933 	return READ_ONCE(sk->sk_ack_backlog) > READ_ONCE(sk->sk_max_ack_backlog);
934 }
935 
936 /*
937  * Compute minimal free write space needed to queue new packets.
938  */
939 static inline int sk_stream_min_wspace(const struct sock *sk)
940 {
941 	return READ_ONCE(sk->sk_wmem_queued) >> 1;
942 }
943 
944 static inline int sk_stream_wspace(const struct sock *sk)
945 {
946 	return READ_ONCE(sk->sk_sndbuf) - READ_ONCE(sk->sk_wmem_queued);
947 }
948 
949 static inline void sk_wmem_queued_add(struct sock *sk, int val)
950 {
951 	WRITE_ONCE(sk->sk_wmem_queued, sk->sk_wmem_queued + val);
952 }
953 
954 void sk_stream_write_space(struct sock *sk);
955 
956 /* OOB backlog add */
957 static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
958 {
959 	/* dont let skb dst not refcounted, we are going to leave rcu lock */
960 	skb_dst_force(skb);
961 
962 	if (!sk->sk_backlog.tail)
963 		WRITE_ONCE(sk->sk_backlog.head, skb);
964 	else
965 		sk->sk_backlog.tail->next = skb;
966 
967 	WRITE_ONCE(sk->sk_backlog.tail, skb);
968 	skb->next = NULL;
969 }
970 
971 /*
972  * Take into account size of receive queue and backlog queue
973  * Do not take into account this skb truesize,
974  * to allow even a single big packet to come.
975  */
976 static inline bool sk_rcvqueues_full(const struct sock *sk, unsigned int limit)
977 {
978 	unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
979 
980 	return qsize > limit;
981 }
982 
983 /* The per-socket spinlock must be held here. */
984 static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
985 					      unsigned int limit)
986 {
987 	if (sk_rcvqueues_full(sk, limit))
988 		return -ENOBUFS;
989 
990 	/*
991 	 * If the skb was allocated from pfmemalloc reserves, only
992 	 * allow SOCK_MEMALLOC sockets to use it as this socket is
993 	 * helping free memory
994 	 */
995 	if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
996 		return -ENOMEM;
997 
998 	__sk_add_backlog(sk, skb);
999 	sk->sk_backlog.len += skb->truesize;
1000 	return 0;
1001 }
1002 
1003 int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
1004 
1005 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
1006 {
1007 	if (sk_memalloc_socks() && skb_pfmemalloc(skb))
1008 		return __sk_backlog_rcv(sk, skb);
1009 
1010 	return sk->sk_backlog_rcv(sk, skb);
1011 }
1012 
1013 static inline void sk_incoming_cpu_update(struct sock *sk)
1014 {
1015 	int cpu = raw_smp_processor_id();
1016 
1017 	if (unlikely(READ_ONCE(sk->sk_incoming_cpu) != cpu))
1018 		WRITE_ONCE(sk->sk_incoming_cpu, cpu);
1019 }
1020 
1021 static inline void sock_rps_record_flow_hash(__u32 hash)
1022 {
1023 #ifdef CONFIG_RPS
1024 	struct rps_sock_flow_table *sock_flow_table;
1025 
1026 	rcu_read_lock();
1027 	sock_flow_table = rcu_dereference(rps_sock_flow_table);
1028 	rps_record_sock_flow(sock_flow_table, hash);
1029 	rcu_read_unlock();
1030 #endif
1031 }
1032 
1033 static inline void sock_rps_record_flow(const struct sock *sk)
1034 {
1035 #ifdef CONFIG_RPS
1036 	if (static_branch_unlikely(&rfs_needed)) {
1037 		/* Reading sk->sk_rxhash might incur an expensive cache line
1038 		 * miss.
1039 		 *
1040 		 * TCP_ESTABLISHED does cover almost all states where RFS
1041 		 * might be useful, and is cheaper [1] than testing :
1042 		 *	IPv4: inet_sk(sk)->inet_daddr
1043 		 * 	IPv6: ipv6_addr_any(&sk->sk_v6_daddr)
1044 		 * OR	an additional socket flag
1045 		 * [1] : sk_state and sk_prot are in the same cache line.
1046 		 */
1047 		if (sk->sk_state == TCP_ESTABLISHED)
1048 			sock_rps_record_flow_hash(sk->sk_rxhash);
1049 	}
1050 #endif
1051 }
1052 
1053 static inline void sock_rps_save_rxhash(struct sock *sk,
1054 					const struct sk_buff *skb)
1055 {
1056 #ifdef CONFIG_RPS
1057 	if (unlikely(sk->sk_rxhash != skb->hash))
1058 		sk->sk_rxhash = skb->hash;
1059 #endif
1060 }
1061 
1062 static inline void sock_rps_reset_rxhash(struct sock *sk)
1063 {
1064 #ifdef CONFIG_RPS
1065 	sk->sk_rxhash = 0;
1066 #endif
1067 }
1068 
1069 #define sk_wait_event(__sk, __timeo, __condition, __wait)		\
1070 	({	int __rc;						\
1071 		release_sock(__sk);					\
1072 		__rc = __condition;					\
1073 		if (!__rc) {						\
1074 			*(__timeo) = wait_woken(__wait,			\
1075 						TASK_INTERRUPTIBLE,	\
1076 						*(__timeo));		\
1077 		}							\
1078 		sched_annotate_sleep();					\
1079 		lock_sock(__sk);					\
1080 		__rc = __condition;					\
1081 		__rc;							\
1082 	})
1083 
1084 int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
1085 int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
1086 void sk_stream_wait_close(struct sock *sk, long timeo_p);
1087 int sk_stream_error(struct sock *sk, int flags, int err);
1088 void sk_stream_kill_queues(struct sock *sk);
1089 void sk_set_memalloc(struct sock *sk);
1090 void sk_clear_memalloc(struct sock *sk);
1091 
1092 void __sk_flush_backlog(struct sock *sk);
1093 
1094 static inline bool sk_flush_backlog(struct sock *sk)
1095 {
1096 	if (unlikely(READ_ONCE(sk->sk_backlog.tail))) {
1097 		__sk_flush_backlog(sk);
1098 		return true;
1099 	}
1100 	return false;
1101 }
1102 
1103 int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb);
1104 
1105 struct request_sock_ops;
1106 struct timewait_sock_ops;
1107 struct inet_hashinfo;
1108 struct raw_hashinfo;
1109 struct smc_hashinfo;
1110 struct module;
1111 
1112 /*
1113  * caches using SLAB_TYPESAFE_BY_RCU should let .next pointer from nulls nodes
1114  * un-modified. Special care is taken when initializing object to zero.
1115  */
1116 static inline void sk_prot_clear_nulls(struct sock *sk, int size)
1117 {
1118 	if (offsetof(struct sock, sk_node.next) != 0)
1119 		memset(sk, 0, offsetof(struct sock, sk_node.next));
1120 	memset(&sk->sk_node.pprev, 0,
1121 	       size - offsetof(struct sock, sk_node.pprev));
1122 }
1123 
1124 /* Networking protocol blocks we attach to sockets.
1125  * socket layer -> transport layer interface
1126  */
1127 struct proto {
1128 	void			(*close)(struct sock *sk,
1129 					long timeout);
1130 	int			(*pre_connect)(struct sock *sk,
1131 					struct sockaddr *uaddr,
1132 					int addr_len);
1133 	int			(*connect)(struct sock *sk,
1134 					struct sockaddr *uaddr,
1135 					int addr_len);
1136 	int			(*disconnect)(struct sock *sk, int flags);
1137 
1138 	struct sock *		(*accept)(struct sock *sk, int flags, int *err,
1139 					  bool kern);
1140 
1141 	int			(*ioctl)(struct sock *sk, int cmd,
1142 					 unsigned long arg);
1143 	int			(*init)(struct sock *sk);
1144 	void			(*destroy)(struct sock *sk);
1145 	void			(*shutdown)(struct sock *sk, int how);
1146 	int			(*setsockopt)(struct sock *sk, int level,
1147 					int optname, sockptr_t optval,
1148 					unsigned int optlen);
1149 	int			(*getsockopt)(struct sock *sk, int level,
1150 					int optname, char __user *optval,
1151 					int __user *option);
1152 	void			(*keepalive)(struct sock *sk, int valbool);
1153 #ifdef CONFIG_COMPAT
1154 	int			(*compat_ioctl)(struct sock *sk,
1155 					unsigned int cmd, unsigned long arg);
1156 #endif
1157 	int			(*sendmsg)(struct sock *sk, struct msghdr *msg,
1158 					   size_t len);
1159 	int			(*recvmsg)(struct sock *sk, struct msghdr *msg,
1160 					   size_t len, int noblock, int flags,
1161 					   int *addr_len);
1162 	int			(*sendpage)(struct sock *sk, struct page *page,
1163 					int offset, size_t size, int flags);
1164 	int			(*bind)(struct sock *sk,
1165 					struct sockaddr *addr, int addr_len);
1166 	int			(*bind_add)(struct sock *sk,
1167 					struct sockaddr *addr, int addr_len);
1168 
1169 	int			(*backlog_rcv) (struct sock *sk,
1170 						struct sk_buff *skb);
1171 
1172 	void		(*release_cb)(struct sock *sk);
1173 
1174 	/* Keeping track of sk's, looking them up, and port selection methods. */
1175 	int			(*hash)(struct sock *sk);
1176 	void			(*unhash)(struct sock *sk);
1177 	void			(*rehash)(struct sock *sk);
1178 	int			(*get_port)(struct sock *sk, unsigned short snum);
1179 
1180 	/* Keeping track of sockets in use */
1181 #ifdef CONFIG_PROC_FS
1182 	unsigned int		inuse_idx;
1183 #endif
1184 
1185 	bool			(*stream_memory_free)(const struct sock *sk, int wake);
1186 	bool			(*stream_memory_read)(const struct sock *sk);
1187 	/* Memory pressure */
1188 	void			(*enter_memory_pressure)(struct sock *sk);
1189 	void			(*leave_memory_pressure)(struct sock *sk);
1190 	atomic_long_t		*memory_allocated;	/* Current allocated memory. */
1191 	struct percpu_counter	*sockets_allocated;	/* Current number of sockets. */
1192 	/*
1193 	 * Pressure flag: try to collapse.
1194 	 * Technical note: it is used by multiple contexts non atomically.
1195 	 * All the __sk_mem_schedule() is of this nature: accounting
1196 	 * is strict, actions are advisory and have some latency.
1197 	 */
1198 	unsigned long		*memory_pressure;
1199 	long			*sysctl_mem;
1200 
1201 	int			*sysctl_wmem;
1202 	int			*sysctl_rmem;
1203 	u32			sysctl_wmem_offset;
1204 	u32			sysctl_rmem_offset;
1205 
1206 	int			max_header;
1207 	bool			no_autobind;
1208 
1209 	struct kmem_cache	*slab;
1210 	unsigned int		obj_size;
1211 	slab_flags_t		slab_flags;
1212 	unsigned int		useroffset;	/* Usercopy region offset */
1213 	unsigned int		usersize;	/* Usercopy region size */
1214 
1215 	struct percpu_counter	*orphan_count;
1216 
1217 	struct request_sock_ops	*rsk_prot;
1218 	struct timewait_sock_ops *twsk_prot;
1219 
1220 	union {
1221 		struct inet_hashinfo	*hashinfo;
1222 		struct udp_table	*udp_table;
1223 		struct raw_hashinfo	*raw_hash;
1224 		struct smc_hashinfo	*smc_hash;
1225 	} h;
1226 
1227 	struct module		*owner;
1228 
1229 	char			name[32];
1230 
1231 	struct list_head	node;
1232 #ifdef SOCK_REFCNT_DEBUG
1233 	atomic_t		socks;
1234 #endif
1235 	int			(*diag_destroy)(struct sock *sk, int err);
1236 } __randomize_layout;
1237 
1238 int proto_register(struct proto *prot, int alloc_slab);
1239 void proto_unregister(struct proto *prot);
1240 int sock_load_diag_module(int family, int protocol);
1241 
1242 #ifdef SOCK_REFCNT_DEBUG
1243 static inline void sk_refcnt_debug_inc(struct sock *sk)
1244 {
1245 	atomic_inc(&sk->sk_prot->socks);
1246 }
1247 
1248 static inline void sk_refcnt_debug_dec(struct sock *sk)
1249 {
1250 	atomic_dec(&sk->sk_prot->socks);
1251 	printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1252 	       sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1253 }
1254 
1255 static inline void sk_refcnt_debug_release(const struct sock *sk)
1256 {
1257 	if (refcount_read(&sk->sk_refcnt) != 1)
1258 		printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1259 		       sk->sk_prot->name, sk, refcount_read(&sk->sk_refcnt));
1260 }
1261 #else /* SOCK_REFCNT_DEBUG */
1262 #define sk_refcnt_debug_inc(sk) do { } while (0)
1263 #define sk_refcnt_debug_dec(sk) do { } while (0)
1264 #define sk_refcnt_debug_release(sk) do { } while (0)
1265 #endif /* SOCK_REFCNT_DEBUG */
1266 
1267 static inline bool __sk_stream_memory_free(const struct sock *sk, int wake)
1268 {
1269 	if (READ_ONCE(sk->sk_wmem_queued) >= READ_ONCE(sk->sk_sndbuf))
1270 		return false;
1271 
1272 	return sk->sk_prot->stream_memory_free ?
1273 		sk->sk_prot->stream_memory_free(sk, wake) : true;
1274 }
1275 
1276 static inline bool sk_stream_memory_free(const struct sock *sk)
1277 {
1278 	return __sk_stream_memory_free(sk, 0);
1279 }
1280 
1281 static inline bool __sk_stream_is_writeable(const struct sock *sk, int wake)
1282 {
1283 	return sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) &&
1284 	       __sk_stream_memory_free(sk, wake);
1285 }
1286 
1287 static inline bool sk_stream_is_writeable(const struct sock *sk)
1288 {
1289 	return __sk_stream_is_writeable(sk, 0);
1290 }
1291 
1292 static inline int sk_under_cgroup_hierarchy(struct sock *sk,
1293 					    struct cgroup *ancestor)
1294 {
1295 #ifdef CONFIG_SOCK_CGROUP_DATA
1296 	return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data),
1297 				    ancestor);
1298 #else
1299 	return -ENOTSUPP;
1300 #endif
1301 }
1302 
1303 static inline bool sk_has_memory_pressure(const struct sock *sk)
1304 {
1305 	return sk->sk_prot->memory_pressure != NULL;
1306 }
1307 
1308 static inline bool sk_under_memory_pressure(const struct sock *sk)
1309 {
1310 	if (!sk->sk_prot->memory_pressure)
1311 		return false;
1312 
1313 	if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
1314 	    mem_cgroup_under_socket_pressure(sk->sk_memcg))
1315 		return true;
1316 
1317 	return !!*sk->sk_prot->memory_pressure;
1318 }
1319 
1320 static inline long
1321 sk_memory_allocated(const struct sock *sk)
1322 {
1323 	return atomic_long_read(sk->sk_prot->memory_allocated);
1324 }
1325 
1326 static inline long
1327 sk_memory_allocated_add(struct sock *sk, int amt)
1328 {
1329 	return atomic_long_add_return(amt, sk->sk_prot->memory_allocated);
1330 }
1331 
1332 static inline void
1333 sk_memory_allocated_sub(struct sock *sk, int amt)
1334 {
1335 	atomic_long_sub(amt, sk->sk_prot->memory_allocated);
1336 }
1337 
1338 static inline void sk_sockets_allocated_dec(struct sock *sk)
1339 {
1340 	percpu_counter_dec(sk->sk_prot->sockets_allocated);
1341 }
1342 
1343 static inline void sk_sockets_allocated_inc(struct sock *sk)
1344 {
1345 	percpu_counter_inc(sk->sk_prot->sockets_allocated);
1346 }
1347 
1348 static inline u64
1349 sk_sockets_allocated_read_positive(struct sock *sk)
1350 {
1351 	return percpu_counter_read_positive(sk->sk_prot->sockets_allocated);
1352 }
1353 
1354 static inline int
1355 proto_sockets_allocated_sum_positive(struct proto *prot)
1356 {
1357 	return percpu_counter_sum_positive(prot->sockets_allocated);
1358 }
1359 
1360 static inline long
1361 proto_memory_allocated(struct proto *prot)
1362 {
1363 	return atomic_long_read(prot->memory_allocated);
1364 }
1365 
1366 static inline bool
1367 proto_memory_pressure(struct proto *prot)
1368 {
1369 	if (!prot->memory_pressure)
1370 		return false;
1371 	return !!*prot->memory_pressure;
1372 }
1373 
1374 
1375 #ifdef CONFIG_PROC_FS
1376 /* Called with local bh disabled */
1377 void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1378 int sock_prot_inuse_get(struct net *net, struct proto *proto);
1379 int sock_inuse_get(struct net *net);
1380 #else
1381 static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1382 		int inc)
1383 {
1384 }
1385 #endif
1386 
1387 
1388 /* With per-bucket locks this operation is not-atomic, so that
1389  * this version is not worse.
1390  */
1391 static inline int __sk_prot_rehash(struct sock *sk)
1392 {
1393 	sk->sk_prot->unhash(sk);
1394 	return sk->sk_prot->hash(sk);
1395 }
1396 
1397 /* About 10 seconds */
1398 #define SOCK_DESTROY_TIME (10*HZ)
1399 
1400 /* Sockets 0-1023 can't be bound to unless you are superuser */
1401 #define PROT_SOCK	1024
1402 
1403 #define SHUTDOWN_MASK	3
1404 #define RCV_SHUTDOWN	1
1405 #define SEND_SHUTDOWN	2
1406 
1407 #define SOCK_SNDBUF_LOCK	1
1408 #define SOCK_RCVBUF_LOCK	2
1409 #define SOCK_BINDADDR_LOCK	4
1410 #define SOCK_BINDPORT_LOCK	8
1411 
1412 struct socket_alloc {
1413 	struct socket socket;
1414 	struct inode vfs_inode;
1415 };
1416 
1417 static inline struct socket *SOCKET_I(struct inode *inode)
1418 {
1419 	return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1420 }
1421 
1422 static inline struct inode *SOCK_INODE(struct socket *socket)
1423 {
1424 	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1425 }
1426 
1427 /*
1428  * Functions for memory accounting
1429  */
1430 int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind);
1431 int __sk_mem_schedule(struct sock *sk, int size, int kind);
1432 void __sk_mem_reduce_allocated(struct sock *sk, int amount);
1433 void __sk_mem_reclaim(struct sock *sk, int amount);
1434 
1435 /* We used to have PAGE_SIZE here, but systems with 64KB pages
1436  * do not necessarily have 16x time more memory than 4KB ones.
1437  */
1438 #define SK_MEM_QUANTUM 4096
1439 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1440 #define SK_MEM_SEND	0
1441 #define SK_MEM_RECV	1
1442 
1443 /* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
1444 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1445 {
1446 	long val = sk->sk_prot->sysctl_mem[index];
1447 
1448 #if PAGE_SIZE > SK_MEM_QUANTUM
1449 	val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
1450 #elif PAGE_SIZE < SK_MEM_QUANTUM
1451 	val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
1452 #endif
1453 	return val;
1454 }
1455 
1456 static inline int sk_mem_pages(int amt)
1457 {
1458 	return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1459 }
1460 
1461 static inline bool sk_has_account(struct sock *sk)
1462 {
1463 	/* return true if protocol supports memory accounting */
1464 	return !!sk->sk_prot->memory_allocated;
1465 }
1466 
1467 static inline bool sk_wmem_schedule(struct sock *sk, int size)
1468 {
1469 	if (!sk_has_account(sk))
1470 		return true;
1471 	return size <= sk->sk_forward_alloc ||
1472 		__sk_mem_schedule(sk, size, SK_MEM_SEND);
1473 }
1474 
1475 static inline bool
1476 sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1477 {
1478 	if (!sk_has_account(sk))
1479 		return true;
1480 	return size <= sk->sk_forward_alloc ||
1481 		__sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1482 		skb_pfmemalloc(skb);
1483 }
1484 
1485 static inline void sk_mem_reclaim(struct sock *sk)
1486 {
1487 	if (!sk_has_account(sk))
1488 		return;
1489 	if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1490 		__sk_mem_reclaim(sk, sk->sk_forward_alloc);
1491 }
1492 
1493 static inline void sk_mem_reclaim_partial(struct sock *sk)
1494 {
1495 	if (!sk_has_account(sk))
1496 		return;
1497 	if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1498 		__sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);
1499 }
1500 
1501 static inline void sk_mem_charge(struct sock *sk, int size)
1502 {
1503 	if (!sk_has_account(sk))
1504 		return;
1505 	sk->sk_forward_alloc -= size;
1506 }
1507 
1508 static inline void sk_mem_uncharge(struct sock *sk, int size)
1509 {
1510 	if (!sk_has_account(sk))
1511 		return;
1512 	sk->sk_forward_alloc += size;
1513 
1514 	/* Avoid a possible overflow.
1515 	 * TCP send queues can make this happen, if sk_mem_reclaim()
1516 	 * is not called and more than 2 GBytes are released at once.
1517 	 *
1518 	 * If we reach 2 MBytes, reclaim 1 MBytes right now, there is
1519 	 * no need to hold that much forward allocation anyway.
1520 	 */
1521 	if (unlikely(sk->sk_forward_alloc >= 1 << 21))
1522 		__sk_mem_reclaim(sk, 1 << 20);
1523 }
1524 
1525 DECLARE_STATIC_KEY_FALSE(tcp_tx_skb_cache_key);
1526 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1527 {
1528 	sk_wmem_queued_add(sk, -skb->truesize);
1529 	sk_mem_uncharge(sk, skb->truesize);
1530 	if (static_branch_unlikely(&tcp_tx_skb_cache_key) &&
1531 	    !sk->sk_tx_skb_cache && !skb_cloned(skb)) {
1532 		skb_ext_reset(skb);
1533 		skb_zcopy_clear(skb, true);
1534 		sk->sk_tx_skb_cache = skb;
1535 		return;
1536 	}
1537 	__kfree_skb(skb);
1538 }
1539 
1540 static inline void sock_release_ownership(struct sock *sk)
1541 {
1542 	if (sk->sk_lock.owned) {
1543 		sk->sk_lock.owned = 0;
1544 
1545 		/* The sk_lock has mutex_unlock() semantics: */
1546 		mutex_release(&sk->sk_lock.dep_map, _RET_IP_);
1547 	}
1548 }
1549 
1550 /*
1551  * Macro so as to not evaluate some arguments when
1552  * lockdep is not enabled.
1553  *
1554  * Mark both the sk_lock and the sk_lock.slock as a
1555  * per-address-family lock class.
1556  */
1557 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)	\
1558 do {									\
1559 	sk->sk_lock.owned = 0;						\
1560 	init_waitqueue_head(&sk->sk_lock.wq);				\
1561 	spin_lock_init(&(sk)->sk_lock.slock);				\
1562 	debug_check_no_locks_freed((void *)&(sk)->sk_lock,		\
1563 			sizeof((sk)->sk_lock));				\
1564 	lockdep_set_class_and_name(&(sk)->sk_lock.slock,		\
1565 				(skey), (sname));				\
1566 	lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);	\
1567 } while (0)
1568 
1569 #ifdef CONFIG_LOCKDEP
1570 static inline bool lockdep_sock_is_held(const struct sock *sk)
1571 {
1572 	return lockdep_is_held(&sk->sk_lock) ||
1573 	       lockdep_is_held(&sk->sk_lock.slock);
1574 }
1575 #endif
1576 
1577 void lock_sock_nested(struct sock *sk, int subclass);
1578 
1579 static inline void lock_sock(struct sock *sk)
1580 {
1581 	lock_sock_nested(sk, 0);
1582 }
1583 
1584 void __release_sock(struct sock *sk);
1585 void release_sock(struct sock *sk);
1586 
1587 /* BH context may only use the following locking interface. */
1588 #define bh_lock_sock(__sk)	spin_lock(&((__sk)->sk_lock.slock))
1589 #define bh_lock_sock_nested(__sk) \
1590 				spin_lock_nested(&((__sk)->sk_lock.slock), \
1591 				SINGLE_DEPTH_NESTING)
1592 #define bh_unlock_sock(__sk)	spin_unlock(&((__sk)->sk_lock.slock))
1593 
1594 bool lock_sock_fast(struct sock *sk);
1595 /**
1596  * unlock_sock_fast - complement of lock_sock_fast
1597  * @sk: socket
1598  * @slow: slow mode
1599  *
1600  * fast unlock socket for user context.
1601  * If slow mode is on, we call regular release_sock()
1602  */
1603 static inline void unlock_sock_fast(struct sock *sk, bool slow)
1604 {
1605 	if (slow)
1606 		release_sock(sk);
1607 	else
1608 		spin_unlock_bh(&sk->sk_lock.slock);
1609 }
1610 
1611 /* Used by processes to "lock" a socket state, so that
1612  * interrupts and bottom half handlers won't change it
1613  * from under us. It essentially blocks any incoming
1614  * packets, so that we won't get any new data or any
1615  * packets that change the state of the socket.
1616  *
1617  * While locked, BH processing will add new packets to
1618  * the backlog queue.  This queue is processed by the
1619  * owner of the socket lock right before it is released.
1620  *
1621  * Since ~2.3.5 it is also exclusive sleep lock serializing
1622  * accesses from user process context.
1623  */
1624 
1625 static inline void sock_owned_by_me(const struct sock *sk)
1626 {
1627 #ifdef CONFIG_LOCKDEP
1628 	WARN_ON_ONCE(!lockdep_sock_is_held(sk) && debug_locks);
1629 #endif
1630 }
1631 
1632 static inline bool sock_owned_by_user(const struct sock *sk)
1633 {
1634 	sock_owned_by_me(sk);
1635 	return sk->sk_lock.owned;
1636 }
1637 
1638 static inline bool sock_owned_by_user_nocheck(const struct sock *sk)
1639 {
1640 	return sk->sk_lock.owned;
1641 }
1642 
1643 /* no reclassification while locks are held */
1644 static inline bool sock_allow_reclassification(const struct sock *csk)
1645 {
1646 	struct sock *sk = (struct sock *)csk;
1647 
1648 	return !sk->sk_lock.owned && !spin_is_locked(&sk->sk_lock.slock);
1649 }
1650 
1651 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
1652 		      struct proto *prot, int kern);
1653 void sk_free(struct sock *sk);
1654 void sk_destruct(struct sock *sk);
1655 struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority);
1656 void sk_free_unlock_clone(struct sock *sk);
1657 
1658 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
1659 			     gfp_t priority);
1660 void __sock_wfree(struct sk_buff *skb);
1661 void sock_wfree(struct sk_buff *skb);
1662 struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size,
1663 			     gfp_t priority);
1664 void skb_orphan_partial(struct sk_buff *skb);
1665 void sock_rfree(struct sk_buff *skb);
1666 void sock_efree(struct sk_buff *skb);
1667 #ifdef CONFIG_INET
1668 void sock_edemux(struct sk_buff *skb);
1669 void sock_pfree(struct sk_buff *skb);
1670 #else
1671 #define sock_edemux sock_efree
1672 #endif
1673 
1674 int sock_setsockopt(struct socket *sock, int level, int op,
1675 		    sockptr_t optval, unsigned int optlen);
1676 
1677 int sock_getsockopt(struct socket *sock, int level, int op,
1678 		    char __user *optval, int __user *optlen);
1679 int sock_gettstamp(struct socket *sock, void __user *userstamp,
1680 		   bool timeval, bool time32);
1681 struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
1682 				    int noblock, int *errcode);
1683 struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
1684 				     unsigned long data_len, int noblock,
1685 				     int *errcode, int max_page_order);
1686 void *sock_kmalloc(struct sock *sk, int size, gfp_t priority);
1687 void sock_kfree_s(struct sock *sk, void *mem, int size);
1688 void sock_kzfree_s(struct sock *sk, void *mem, int size);
1689 void sk_send_sigurg(struct sock *sk);
1690 
1691 struct sockcm_cookie {
1692 	u64 transmit_time;
1693 	u32 mark;
1694 	u16 tsflags;
1695 };
1696 
1697 static inline void sockcm_init(struct sockcm_cookie *sockc,
1698 			       const struct sock *sk)
1699 {
1700 	*sockc = (struct sockcm_cookie) { .tsflags = sk->sk_tsflags };
1701 }
1702 
1703 int __sock_cmsg_send(struct sock *sk, struct msghdr *msg, struct cmsghdr *cmsg,
1704 		     struct sockcm_cookie *sockc);
1705 int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
1706 		   struct sockcm_cookie *sockc);
1707 
1708 /*
1709  * Functions to fill in entries in struct proto_ops when a protocol
1710  * does not implement a particular function.
1711  */
1712 int sock_no_bind(struct socket *, struct sockaddr *, int);
1713 int sock_no_connect(struct socket *, struct sockaddr *, int, int);
1714 int sock_no_socketpair(struct socket *, struct socket *);
1715 int sock_no_accept(struct socket *, struct socket *, int, bool);
1716 int sock_no_getname(struct socket *, struct sockaddr *, int);
1717 int sock_no_ioctl(struct socket *, unsigned int, unsigned long);
1718 int sock_no_listen(struct socket *, int);
1719 int sock_no_shutdown(struct socket *, int);
1720 int sock_no_sendmsg(struct socket *, struct msghdr *, size_t);
1721 int sock_no_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t len);
1722 int sock_no_recvmsg(struct socket *, struct msghdr *, size_t, int);
1723 int sock_no_mmap(struct file *file, struct socket *sock,
1724 		 struct vm_area_struct *vma);
1725 ssize_t sock_no_sendpage(struct socket *sock, struct page *page, int offset,
1726 			 size_t size, int flags);
1727 ssize_t sock_no_sendpage_locked(struct sock *sk, struct page *page,
1728 				int offset, size_t size, int flags);
1729 
1730 /*
1731  * Functions to fill in entries in struct proto_ops when a protocol
1732  * uses the inet style.
1733  */
1734 int sock_common_getsockopt(struct socket *sock, int level, int optname,
1735 				  char __user *optval, int __user *optlen);
1736 int sock_common_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1737 			int flags);
1738 int sock_common_setsockopt(struct socket *sock, int level, int optname,
1739 			   sockptr_t optval, unsigned int optlen);
1740 
1741 void sk_common_release(struct sock *sk);
1742 
1743 /*
1744  *	Default socket callbacks and setup code
1745  */
1746 
1747 /* Initialise core socket variables */
1748 void sock_init_data(struct socket *sock, struct sock *sk);
1749 
1750 /*
1751  * Socket reference counting postulates.
1752  *
1753  * * Each user of socket SHOULD hold a reference count.
1754  * * Each access point to socket (an hash table bucket, reference from a list,
1755  *   running timer, skb in flight MUST hold a reference count.
1756  * * When reference count hits 0, it means it will never increase back.
1757  * * When reference count hits 0, it means that no references from
1758  *   outside exist to this socket and current process on current CPU
1759  *   is last user and may/should destroy this socket.
1760  * * sk_free is called from any context: process, BH, IRQ. When
1761  *   it is called, socket has no references from outside -> sk_free
1762  *   may release descendant resources allocated by the socket, but
1763  *   to the time when it is called, socket is NOT referenced by any
1764  *   hash tables, lists etc.
1765  * * Packets, delivered from outside (from network or from another process)
1766  *   and enqueued on receive/error queues SHOULD NOT grab reference count,
1767  *   when they sit in queue. Otherwise, packets will leak to hole, when
1768  *   socket is looked up by one cpu and unhasing is made by another CPU.
1769  *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
1770  *   (leak to backlog). Packet socket does all the processing inside
1771  *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
1772  *   use separate SMP lock, so that they are prone too.
1773  */
1774 
1775 /* Ungrab socket and destroy it, if it was the last reference. */
1776 static inline void sock_put(struct sock *sk)
1777 {
1778 	if (refcount_dec_and_test(&sk->sk_refcnt))
1779 		sk_free(sk);
1780 }
1781 /* Generic version of sock_put(), dealing with all sockets
1782  * (TCP_TIMEWAIT, TCP_NEW_SYN_RECV, ESTABLISHED...)
1783  */
1784 void sock_gen_put(struct sock *sk);
1785 
1786 int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested,
1787 		     unsigned int trim_cap, bool refcounted);
1788 static inline int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
1789 				 const int nested)
1790 {
1791 	return __sk_receive_skb(sk, skb, nested, 1, true);
1792 }
1793 
1794 static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
1795 {
1796 	/* sk_tx_queue_mapping accept only upto a 16-bit value */
1797 	if (WARN_ON_ONCE((unsigned short)tx_queue >= USHRT_MAX))
1798 		return;
1799 	sk->sk_tx_queue_mapping = tx_queue;
1800 }
1801 
1802 #define NO_QUEUE_MAPPING	USHRT_MAX
1803 
1804 static inline void sk_tx_queue_clear(struct sock *sk)
1805 {
1806 	sk->sk_tx_queue_mapping = NO_QUEUE_MAPPING;
1807 }
1808 
1809 static inline int sk_tx_queue_get(const struct sock *sk)
1810 {
1811 	if (sk && sk->sk_tx_queue_mapping != NO_QUEUE_MAPPING)
1812 		return sk->sk_tx_queue_mapping;
1813 
1814 	return -1;
1815 }
1816 
1817 static inline void sk_rx_queue_set(struct sock *sk, const struct sk_buff *skb)
1818 {
1819 #ifdef CONFIG_XPS
1820 	if (skb_rx_queue_recorded(skb)) {
1821 		u16 rx_queue = skb_get_rx_queue(skb);
1822 
1823 		if (WARN_ON_ONCE(rx_queue == NO_QUEUE_MAPPING))
1824 			return;
1825 
1826 		sk->sk_rx_queue_mapping = rx_queue;
1827 	}
1828 #endif
1829 }
1830 
1831 static inline void sk_rx_queue_clear(struct sock *sk)
1832 {
1833 #ifdef CONFIG_XPS
1834 	sk->sk_rx_queue_mapping = NO_QUEUE_MAPPING;
1835 #endif
1836 }
1837 
1838 #ifdef CONFIG_XPS
1839 static inline int sk_rx_queue_get(const struct sock *sk)
1840 {
1841 	if (sk && sk->sk_rx_queue_mapping != NO_QUEUE_MAPPING)
1842 		return sk->sk_rx_queue_mapping;
1843 
1844 	return -1;
1845 }
1846 #endif
1847 
1848 static inline void sk_set_socket(struct sock *sk, struct socket *sock)
1849 {
1850 	sk->sk_socket = sock;
1851 }
1852 
1853 static inline wait_queue_head_t *sk_sleep(struct sock *sk)
1854 {
1855 	BUILD_BUG_ON(offsetof(struct socket_wq, wait) != 0);
1856 	return &rcu_dereference_raw(sk->sk_wq)->wait;
1857 }
1858 /* Detach socket from process context.
1859  * Announce socket dead, detach it from wait queue and inode.
1860  * Note that parent inode held reference count on this struct sock,
1861  * we do not release it in this function, because protocol
1862  * probably wants some additional cleanups or even continuing
1863  * to work with this socket (TCP).
1864  */
1865 static inline void sock_orphan(struct sock *sk)
1866 {
1867 	write_lock_bh(&sk->sk_callback_lock);
1868 	sock_set_flag(sk, SOCK_DEAD);
1869 	sk_set_socket(sk, NULL);
1870 	sk->sk_wq  = NULL;
1871 	write_unlock_bh(&sk->sk_callback_lock);
1872 }
1873 
1874 static inline void sock_graft(struct sock *sk, struct socket *parent)
1875 {
1876 	WARN_ON(parent->sk);
1877 	write_lock_bh(&sk->sk_callback_lock);
1878 	rcu_assign_pointer(sk->sk_wq, &parent->wq);
1879 	parent->sk = sk;
1880 	sk_set_socket(sk, parent);
1881 	sk->sk_uid = SOCK_INODE(parent)->i_uid;
1882 	security_sock_graft(sk, parent);
1883 	write_unlock_bh(&sk->sk_callback_lock);
1884 }
1885 
1886 kuid_t sock_i_uid(struct sock *sk);
1887 unsigned long sock_i_ino(struct sock *sk);
1888 
1889 static inline kuid_t sock_net_uid(const struct net *net, const struct sock *sk)
1890 {
1891 	return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
1892 }
1893 
1894 static inline u32 net_tx_rndhash(void)
1895 {
1896 	u32 v = prandom_u32();
1897 
1898 	return v ?: 1;
1899 }
1900 
1901 static inline void sk_set_txhash(struct sock *sk)
1902 {
1903 	sk->sk_txhash = net_tx_rndhash();
1904 }
1905 
1906 static inline void sk_rethink_txhash(struct sock *sk)
1907 {
1908 	if (sk->sk_txhash)
1909 		sk_set_txhash(sk);
1910 }
1911 
1912 static inline struct dst_entry *
1913 __sk_dst_get(struct sock *sk)
1914 {
1915 	return rcu_dereference_check(sk->sk_dst_cache,
1916 				     lockdep_sock_is_held(sk));
1917 }
1918 
1919 static inline struct dst_entry *
1920 sk_dst_get(struct sock *sk)
1921 {
1922 	struct dst_entry *dst;
1923 
1924 	rcu_read_lock();
1925 	dst = rcu_dereference(sk->sk_dst_cache);
1926 	if (dst && !atomic_inc_not_zero(&dst->__refcnt))
1927 		dst = NULL;
1928 	rcu_read_unlock();
1929 	return dst;
1930 }
1931 
1932 static inline void dst_negative_advice(struct sock *sk)
1933 {
1934 	struct dst_entry *ndst, *dst = __sk_dst_get(sk);
1935 
1936 	sk_rethink_txhash(sk);
1937 
1938 	if (dst && dst->ops->negative_advice) {
1939 		ndst = dst->ops->negative_advice(dst);
1940 
1941 		if (ndst != dst) {
1942 			rcu_assign_pointer(sk->sk_dst_cache, ndst);
1943 			sk_tx_queue_clear(sk);
1944 			sk->sk_dst_pending_confirm = 0;
1945 		}
1946 	}
1947 }
1948 
1949 static inline void
1950 __sk_dst_set(struct sock *sk, struct dst_entry *dst)
1951 {
1952 	struct dst_entry *old_dst;
1953 
1954 	sk_tx_queue_clear(sk);
1955 	sk->sk_dst_pending_confirm = 0;
1956 	old_dst = rcu_dereference_protected(sk->sk_dst_cache,
1957 					    lockdep_sock_is_held(sk));
1958 	rcu_assign_pointer(sk->sk_dst_cache, dst);
1959 	dst_release(old_dst);
1960 }
1961 
1962 static inline void
1963 sk_dst_set(struct sock *sk, struct dst_entry *dst)
1964 {
1965 	struct dst_entry *old_dst;
1966 
1967 	sk_tx_queue_clear(sk);
1968 	sk->sk_dst_pending_confirm = 0;
1969 	old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
1970 	dst_release(old_dst);
1971 }
1972 
1973 static inline void
1974 __sk_dst_reset(struct sock *sk)
1975 {
1976 	__sk_dst_set(sk, NULL);
1977 }
1978 
1979 static inline void
1980 sk_dst_reset(struct sock *sk)
1981 {
1982 	sk_dst_set(sk, NULL);
1983 }
1984 
1985 struct dst_entry *__sk_dst_check(struct sock *sk, u32 cookie);
1986 
1987 struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie);
1988 
1989 static inline void sk_dst_confirm(struct sock *sk)
1990 {
1991 	if (!READ_ONCE(sk->sk_dst_pending_confirm))
1992 		WRITE_ONCE(sk->sk_dst_pending_confirm, 1);
1993 }
1994 
1995 static inline void sock_confirm_neigh(struct sk_buff *skb, struct neighbour *n)
1996 {
1997 	if (skb_get_dst_pending_confirm(skb)) {
1998 		struct sock *sk = skb->sk;
1999 		unsigned long now = jiffies;
2000 
2001 		/* avoid dirtying neighbour */
2002 		if (READ_ONCE(n->confirmed) != now)
2003 			WRITE_ONCE(n->confirmed, now);
2004 		if (sk && READ_ONCE(sk->sk_dst_pending_confirm))
2005 			WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
2006 	}
2007 }
2008 
2009 bool sk_mc_loop(struct sock *sk);
2010 
2011 static inline bool sk_can_gso(const struct sock *sk)
2012 {
2013 	return net_gso_ok(sk->sk_route_caps, sk->sk_gso_type);
2014 }
2015 
2016 void sk_setup_caps(struct sock *sk, struct dst_entry *dst);
2017 
2018 static inline void sk_nocaps_add(struct sock *sk, netdev_features_t flags)
2019 {
2020 	sk->sk_route_nocaps |= flags;
2021 	sk->sk_route_caps &= ~flags;
2022 }
2023 
2024 static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
2025 					   struct iov_iter *from, char *to,
2026 					   int copy, int offset)
2027 {
2028 	if (skb->ip_summed == CHECKSUM_NONE) {
2029 		__wsum csum = 0;
2030 		if (!csum_and_copy_from_iter_full(to, copy, &csum, from))
2031 			return -EFAULT;
2032 		skb->csum = csum_block_add(skb->csum, csum, offset);
2033 	} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
2034 		if (!copy_from_iter_full_nocache(to, copy, from))
2035 			return -EFAULT;
2036 	} else if (!copy_from_iter_full(to, copy, from))
2037 		return -EFAULT;
2038 
2039 	return 0;
2040 }
2041 
2042 static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
2043 				       struct iov_iter *from, int copy)
2044 {
2045 	int err, offset = skb->len;
2046 
2047 	err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
2048 				       copy, offset);
2049 	if (err)
2050 		__skb_trim(skb, offset);
2051 
2052 	return err;
2053 }
2054 
2055 static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *from,
2056 					   struct sk_buff *skb,
2057 					   struct page *page,
2058 					   int off, int copy)
2059 {
2060 	int err;
2061 
2062 	err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
2063 				       copy, skb->len);
2064 	if (err)
2065 		return err;
2066 
2067 	skb->len	     += copy;
2068 	skb->data_len	     += copy;
2069 	skb->truesize	     += copy;
2070 	sk_wmem_queued_add(sk, copy);
2071 	sk_mem_charge(sk, copy);
2072 	return 0;
2073 }
2074 
2075 /**
2076  * sk_wmem_alloc_get - returns write allocations
2077  * @sk: socket
2078  *
2079  * Return: sk_wmem_alloc minus initial offset of one
2080  */
2081 static inline int sk_wmem_alloc_get(const struct sock *sk)
2082 {
2083 	return refcount_read(&sk->sk_wmem_alloc) - 1;
2084 }
2085 
2086 /**
2087  * sk_rmem_alloc_get - returns read allocations
2088  * @sk: socket
2089  *
2090  * Return: sk_rmem_alloc
2091  */
2092 static inline int sk_rmem_alloc_get(const struct sock *sk)
2093 {
2094 	return atomic_read(&sk->sk_rmem_alloc);
2095 }
2096 
2097 /**
2098  * sk_has_allocations - check if allocations are outstanding
2099  * @sk: socket
2100  *
2101  * Return: true if socket has write or read allocations
2102  */
2103 static inline bool sk_has_allocations(const struct sock *sk)
2104 {
2105 	return sk_wmem_alloc_get(sk) || sk_rmem_alloc_get(sk);
2106 }
2107 
2108 /**
2109  * skwq_has_sleeper - check if there are any waiting processes
2110  * @wq: struct socket_wq
2111  *
2112  * Return: true if socket_wq has waiting processes
2113  *
2114  * The purpose of the skwq_has_sleeper and sock_poll_wait is to wrap the memory
2115  * barrier call. They were added due to the race found within the tcp code.
2116  *
2117  * Consider following tcp code paths::
2118  *
2119  *   CPU1                CPU2
2120  *   sys_select          receive packet
2121  *   ...                 ...
2122  *   __add_wait_queue    update tp->rcv_nxt
2123  *   ...                 ...
2124  *   tp->rcv_nxt check   sock_def_readable
2125  *   ...                 {
2126  *   schedule               rcu_read_lock();
2127  *                          wq = rcu_dereference(sk->sk_wq);
2128  *                          if (wq && waitqueue_active(&wq->wait))
2129  *                              wake_up_interruptible(&wq->wait)
2130  *                          ...
2131  *                       }
2132  *
2133  * The race for tcp fires when the __add_wait_queue changes done by CPU1 stay
2134  * in its cache, and so does the tp->rcv_nxt update on CPU2 side.  The CPU1
2135  * could then endup calling schedule and sleep forever if there are no more
2136  * data on the socket.
2137  *
2138  */
2139 static inline bool skwq_has_sleeper(struct socket_wq *wq)
2140 {
2141 	return wq && wq_has_sleeper(&wq->wait);
2142 }
2143 
2144 /**
2145  * sock_poll_wait - place memory barrier behind the poll_wait call.
2146  * @filp:           file
2147  * @sock:           socket to wait on
2148  * @p:              poll_table
2149  *
2150  * See the comments in the wq_has_sleeper function.
2151  */
2152 static inline void sock_poll_wait(struct file *filp, struct socket *sock,
2153 				  poll_table *p)
2154 {
2155 	if (!poll_does_not_wait(p)) {
2156 		poll_wait(filp, &sock->wq.wait, p);
2157 		/* We need to be sure we are in sync with the
2158 		 * socket flags modification.
2159 		 *
2160 		 * This memory barrier is paired in the wq_has_sleeper.
2161 		 */
2162 		smp_mb();
2163 	}
2164 }
2165 
2166 static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)
2167 {
2168 	if (sk->sk_txhash) {
2169 		skb->l4_hash = 1;
2170 		skb->hash = sk->sk_txhash;
2171 	}
2172 }
2173 
2174 void skb_set_owner_w(struct sk_buff *skb, struct sock *sk);
2175 
2176 /*
2177  *	Queue a received datagram if it will fit. Stream and sequenced
2178  *	protocols can't normally use this as they need to fit buffers in
2179  *	and play with them.
2180  *
2181  *	Inlined as it's very short and called for pretty much every
2182  *	packet ever received.
2183  */
2184 static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
2185 {
2186 	skb_orphan(skb);
2187 	skb->sk = sk;
2188 	skb->destructor = sock_rfree;
2189 	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
2190 	sk_mem_charge(sk, skb->truesize);
2191 }
2192 
2193 void sk_reset_timer(struct sock *sk, struct timer_list *timer,
2194 		    unsigned long expires);
2195 
2196 void sk_stop_timer(struct sock *sk, struct timer_list *timer);
2197 
2198 void sk_stop_timer_sync(struct sock *sk, struct timer_list *timer);
2199 
2200 int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue,
2201 			struct sk_buff *skb, unsigned int flags,
2202 			void (*destructor)(struct sock *sk,
2203 					   struct sk_buff *skb));
2204 int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2205 int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
2206 
2207 int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
2208 struct sk_buff *sock_dequeue_err_skb(struct sock *sk);
2209 
2210 /*
2211  *	Recover an error report and clear atomically
2212  */
2213 
2214 static inline int sock_error(struct sock *sk)
2215 {
2216 	int err;
2217 	if (likely(!sk->sk_err))
2218 		return 0;
2219 	err = xchg(&sk->sk_err, 0);
2220 	return -err;
2221 }
2222 
2223 static inline unsigned long sock_wspace(struct sock *sk)
2224 {
2225 	int amt = 0;
2226 
2227 	if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
2228 		amt = sk->sk_sndbuf - refcount_read(&sk->sk_wmem_alloc);
2229 		if (amt < 0)
2230 			amt = 0;
2231 	}
2232 	return amt;
2233 }
2234 
2235 /* Note:
2236  *  We use sk->sk_wq_raw, from contexts knowing this
2237  *  pointer is not NULL and cannot disappear/change.
2238  */
2239 static inline void sk_set_bit(int nr, struct sock *sk)
2240 {
2241 	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2242 	    !sock_flag(sk, SOCK_FASYNC))
2243 		return;
2244 
2245 	set_bit(nr, &sk->sk_wq_raw->flags);
2246 }
2247 
2248 static inline void sk_clear_bit(int nr, struct sock *sk)
2249 {
2250 	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
2251 	    !sock_flag(sk, SOCK_FASYNC))
2252 		return;
2253 
2254 	clear_bit(nr, &sk->sk_wq_raw->flags);
2255 }
2256 
2257 static inline void sk_wake_async(const struct sock *sk, int how, int band)
2258 {
2259 	if (sock_flag(sk, SOCK_FASYNC)) {
2260 		rcu_read_lock();
2261 		sock_wake_async(rcu_dereference(sk->sk_wq), how, band);
2262 		rcu_read_unlock();
2263 	}
2264 }
2265 
2266 /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
2267  * need sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak.
2268  * Note: for send buffers, TCP works better if we can build two skbs at
2269  * minimum.
2270  */
2271 #define TCP_SKB_MIN_TRUESIZE	(2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
2272 
2273 #define SOCK_MIN_SNDBUF		(TCP_SKB_MIN_TRUESIZE * 2)
2274 #define SOCK_MIN_RCVBUF		 TCP_SKB_MIN_TRUESIZE
2275 
2276 static inline void sk_stream_moderate_sndbuf(struct sock *sk)
2277 {
2278 	u32 val;
2279 
2280 	if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
2281 		return;
2282 
2283 	val = min(sk->sk_sndbuf, sk->sk_wmem_queued >> 1);
2284 
2285 	WRITE_ONCE(sk->sk_sndbuf, max_t(u32, val, SOCK_MIN_SNDBUF));
2286 }
2287 
2288 struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
2289 				    bool force_schedule);
2290 
2291 /**
2292  * sk_page_frag - return an appropriate page_frag
2293  * @sk: socket
2294  *
2295  * Use the per task page_frag instead of the per socket one for
2296  * optimization when we know that we're in the normal context and owns
2297  * everything that's associated with %current.
2298  *
2299  * gfpflags_allow_blocking() isn't enough here as direct reclaim may nest
2300  * inside other socket operations and end up recursing into sk_page_frag()
2301  * while it's already in use.
2302  *
2303  * Return: a per task page_frag if context allows that,
2304  * otherwise a per socket one.
2305  */
2306 static inline struct page_frag *sk_page_frag(struct sock *sk)
2307 {
2308 	if (gfpflags_normal_context(sk->sk_allocation))
2309 		return &current->task_frag;
2310 
2311 	return &sk->sk_frag;
2312 }
2313 
2314 bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag);
2315 
2316 /*
2317  *	Default write policy as shown to user space via poll/select/SIGIO
2318  */
2319 static inline bool sock_writeable(const struct sock *sk)
2320 {
2321 	return refcount_read(&sk->sk_wmem_alloc) < (READ_ONCE(sk->sk_sndbuf) >> 1);
2322 }
2323 
2324 static inline gfp_t gfp_any(void)
2325 {
2326 	return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
2327 }
2328 
2329 static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2330 {
2331 	return noblock ? 0 : sk->sk_rcvtimeo;
2332 }
2333 
2334 static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2335 {
2336 	return noblock ? 0 : sk->sk_sndtimeo;
2337 }
2338 
2339 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2340 {
2341 	int v = waitall ? len : min_t(int, READ_ONCE(sk->sk_rcvlowat), len);
2342 
2343 	return v ?: 1;
2344 }
2345 
2346 /* Alas, with timeout socket operations are not restartable.
2347  * Compare this to poll().
2348  */
2349 static inline int sock_intr_errno(long timeo)
2350 {
2351 	return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2352 }
2353 
2354 struct sock_skb_cb {
2355 	u32 dropcount;
2356 };
2357 
2358 /* Store sock_skb_cb at the end of skb->cb[] so protocol families
2359  * using skb->cb[] would keep using it directly and utilize its
2360  * alignement guarantee.
2361  */
2362 #define SOCK_SKB_CB_OFFSET ((sizeof_field(struct sk_buff, cb) - \
2363 			    sizeof(struct sock_skb_cb)))
2364 
2365 #define SOCK_SKB_CB(__skb) ((struct sock_skb_cb *)((__skb)->cb + \
2366 			    SOCK_SKB_CB_OFFSET))
2367 
2368 #define sock_skb_cb_check_size(size) \
2369 	BUILD_BUG_ON((size) > SOCK_SKB_CB_OFFSET)
2370 
2371 static inline void
2372 sock_skb_set_dropcount(const struct sock *sk, struct sk_buff *skb)
2373 {
2374 	SOCK_SKB_CB(skb)->dropcount = sock_flag(sk, SOCK_RXQ_OVFL) ?
2375 						atomic_read(&sk->sk_drops) : 0;
2376 }
2377 
2378 static inline void sk_drops_add(struct sock *sk, const struct sk_buff *skb)
2379 {
2380 	int segs = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
2381 
2382 	atomic_add(segs, &sk->sk_drops);
2383 }
2384 
2385 static inline ktime_t sock_read_timestamp(struct sock *sk)
2386 {
2387 #if BITS_PER_LONG==32
2388 	unsigned int seq;
2389 	ktime_t kt;
2390 
2391 	do {
2392 		seq = read_seqbegin(&sk->sk_stamp_seq);
2393 		kt = sk->sk_stamp;
2394 	} while (read_seqretry(&sk->sk_stamp_seq, seq));
2395 
2396 	return kt;
2397 #else
2398 	return READ_ONCE(sk->sk_stamp);
2399 #endif
2400 }
2401 
2402 static inline void sock_write_timestamp(struct sock *sk, ktime_t kt)
2403 {
2404 #if BITS_PER_LONG==32
2405 	write_seqlock(&sk->sk_stamp_seq);
2406 	sk->sk_stamp = kt;
2407 	write_sequnlock(&sk->sk_stamp_seq);
2408 #else
2409 	WRITE_ONCE(sk->sk_stamp, kt);
2410 #endif
2411 }
2412 
2413 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2414 			   struct sk_buff *skb);
2415 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2416 			     struct sk_buff *skb);
2417 
2418 static inline void
2419 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2420 {
2421 	ktime_t kt = skb->tstamp;
2422 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2423 
2424 	/*
2425 	 * generate control messages if
2426 	 * - receive time stamping in software requested
2427 	 * - software time stamp available and wanted
2428 	 * - hardware time stamps available and wanted
2429 	 */
2430 	if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2431 	    (sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
2432 	    (kt && sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
2433 	    (hwtstamps->hwtstamp &&
2434 	     (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
2435 		__sock_recv_timestamp(msg, sk, skb);
2436 	else
2437 		sock_write_timestamp(sk, kt);
2438 
2439 	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2440 		__sock_recv_wifi_status(msg, sk, skb);
2441 }
2442 
2443 void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2444 			      struct sk_buff *skb);
2445 
2446 #define SK_DEFAULT_STAMP (-1L * NSEC_PER_SEC)
2447 static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2448 					  struct sk_buff *skb)
2449 {
2450 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)			| \
2451 			   (1UL << SOCK_RCVTSTAMP))
2452 #define TSFLAGS_ANY	  (SOF_TIMESTAMPING_SOFTWARE			| \
2453 			   SOF_TIMESTAMPING_RAW_HARDWARE)
2454 
2455 	if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY)
2456 		__sock_recv_ts_and_drops(msg, sk, skb);
2457 	else if (unlikely(sock_flag(sk, SOCK_TIMESTAMP)))
2458 		sock_write_timestamp(sk, skb->tstamp);
2459 	else if (unlikely(sk->sk_stamp == SK_DEFAULT_STAMP))
2460 		sock_write_timestamp(sk, 0);
2461 }
2462 
2463 void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags);
2464 
2465 /**
2466  * _sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2467  * @sk:		socket sending this packet
2468  * @tsflags:	timestamping flags to use
2469  * @tx_flags:	completed with instructions for time stamping
2470  * @tskey:      filled in with next sk_tskey (not for TCP, which uses seqno)
2471  *
2472  * Note: callers should take care of initial ``*tx_flags`` value (usually 0)
2473  */
2474 static inline void _sock_tx_timestamp(struct sock *sk, __u16 tsflags,
2475 				      __u8 *tx_flags, __u32 *tskey)
2476 {
2477 	if (unlikely(tsflags)) {
2478 		__sock_tx_timestamp(tsflags, tx_flags);
2479 		if (tsflags & SOF_TIMESTAMPING_OPT_ID && tskey &&
2480 		    tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
2481 			*tskey = sk->sk_tskey++;
2482 	}
2483 	if (unlikely(sock_flag(sk, SOCK_WIFI_STATUS)))
2484 		*tx_flags |= SKBTX_WIFI_STATUS;
2485 }
2486 
2487 static inline void sock_tx_timestamp(struct sock *sk, __u16 tsflags,
2488 				     __u8 *tx_flags)
2489 {
2490 	_sock_tx_timestamp(sk, tsflags, tx_flags, NULL);
2491 }
2492 
2493 static inline void skb_setup_tx_timestamp(struct sk_buff *skb, __u16 tsflags)
2494 {
2495 	_sock_tx_timestamp(skb->sk, tsflags, &skb_shinfo(skb)->tx_flags,
2496 			   &skb_shinfo(skb)->tskey);
2497 }
2498 
2499 DECLARE_STATIC_KEY_FALSE(tcp_rx_skb_cache_key);
2500 /**
2501  * sk_eat_skb - Release a skb if it is no longer needed
2502  * @sk: socket to eat this skb from
2503  * @skb: socket buffer to eat
2504  *
2505  * This routine must be called with interrupts disabled or with the socket
2506  * locked so that the sk_buff queue operation is ok.
2507 */
2508 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb)
2509 {
2510 	__skb_unlink(skb, &sk->sk_receive_queue);
2511 	if (static_branch_unlikely(&tcp_rx_skb_cache_key) &&
2512 	    !sk->sk_rx_skb_cache) {
2513 		sk->sk_rx_skb_cache = skb;
2514 		skb_orphan(skb);
2515 		return;
2516 	}
2517 	__kfree_skb(skb);
2518 }
2519 
2520 static inline
2521 struct net *sock_net(const struct sock *sk)
2522 {
2523 	return read_pnet(&sk->sk_net);
2524 }
2525 
2526 static inline
2527 void sock_net_set(struct sock *sk, struct net *net)
2528 {
2529 	write_pnet(&sk->sk_net, net);
2530 }
2531 
2532 static inline bool
2533 skb_sk_is_prefetched(struct sk_buff *skb)
2534 {
2535 #ifdef CONFIG_INET
2536 	return skb->destructor == sock_pfree;
2537 #else
2538 	return false;
2539 #endif /* CONFIG_INET */
2540 }
2541 
2542 /* This helper checks if a socket is a full socket,
2543  * ie _not_ a timewait or request socket.
2544  */
2545 static inline bool sk_fullsock(const struct sock *sk)
2546 {
2547 	return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
2548 }
2549 
2550 static inline bool
2551 sk_is_refcounted(struct sock *sk)
2552 {
2553 	/* Only full sockets have sk->sk_flags. */
2554 	return !sk_fullsock(sk) || !sock_flag(sk, SOCK_RCU_FREE);
2555 }
2556 
2557 /**
2558  * skb_steal_sock - steal a socket from an sk_buff
2559  * @skb: sk_buff to steal the socket from
2560  * @refcounted: is set to true if the socket is reference-counted
2561  */
2562 static inline struct sock *
2563 skb_steal_sock(struct sk_buff *skb, bool *refcounted)
2564 {
2565 	if (skb->sk) {
2566 		struct sock *sk = skb->sk;
2567 
2568 		*refcounted = true;
2569 		if (skb_sk_is_prefetched(skb))
2570 			*refcounted = sk_is_refcounted(sk);
2571 		skb->destructor = NULL;
2572 		skb->sk = NULL;
2573 		return sk;
2574 	}
2575 	*refcounted = false;
2576 	return NULL;
2577 }
2578 
2579 /* Checks if this SKB belongs to an HW offloaded socket
2580  * and whether any SW fallbacks are required based on dev.
2581  * Check decrypted mark in case skb_orphan() cleared socket.
2582  */
2583 static inline struct sk_buff *sk_validate_xmit_skb(struct sk_buff *skb,
2584 						   struct net_device *dev)
2585 {
2586 #ifdef CONFIG_SOCK_VALIDATE_XMIT
2587 	struct sock *sk = skb->sk;
2588 
2589 	if (sk && sk_fullsock(sk) && sk->sk_validate_xmit_skb) {
2590 		skb = sk->sk_validate_xmit_skb(sk, dev, skb);
2591 #ifdef CONFIG_TLS_DEVICE
2592 	} else if (unlikely(skb->decrypted)) {
2593 		pr_warn_ratelimited("unencrypted skb with no associated socket - dropping\n");
2594 		kfree_skb(skb);
2595 		skb = NULL;
2596 #endif
2597 	}
2598 #endif
2599 
2600 	return skb;
2601 }
2602 
2603 /* This helper checks if a socket is a LISTEN or NEW_SYN_RECV
2604  * SYNACK messages can be attached to either ones (depending on SYNCOOKIE)
2605  */
2606 static inline bool sk_listener(const struct sock *sk)
2607 {
2608 	return (1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV);
2609 }
2610 
2611 void sock_enable_timestamp(struct sock *sk, enum sock_flags flag);
2612 int sock_recv_errqueue(struct sock *sk, struct msghdr *msg, int len, int level,
2613 		       int type);
2614 
2615 bool sk_ns_capable(const struct sock *sk,
2616 		   struct user_namespace *user_ns, int cap);
2617 bool sk_capable(const struct sock *sk, int cap);
2618 bool sk_net_capable(const struct sock *sk, int cap);
2619 
2620 void sk_get_meminfo(const struct sock *sk, u32 *meminfo);
2621 
2622 /* Take into consideration the size of the struct sk_buff overhead in the
2623  * determination of these values, since that is non-constant across
2624  * platforms.  This makes socket queueing behavior and performance
2625  * not depend upon such differences.
2626  */
2627 #define _SK_MEM_PACKETS		256
2628 #define _SK_MEM_OVERHEAD	SKB_TRUESIZE(256)
2629 #define SK_WMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2630 #define SK_RMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2631 
2632 extern __u32 sysctl_wmem_max;
2633 extern __u32 sysctl_rmem_max;
2634 
2635 extern int sysctl_tstamp_allow_data;
2636 extern int sysctl_optmem_max;
2637 
2638 extern __u32 sysctl_wmem_default;
2639 extern __u32 sysctl_rmem_default;
2640 
2641 DECLARE_STATIC_KEY_FALSE(net_high_order_alloc_disable_key);
2642 
2643 static inline int sk_get_wmem0(const struct sock *sk, const struct proto *proto)
2644 {
2645 	/* Does this proto have per netns sysctl_wmem ? */
2646 	if (proto->sysctl_wmem_offset)
2647 		return *(int *)((void *)sock_net(sk) + proto->sysctl_wmem_offset);
2648 
2649 	return *proto->sysctl_wmem;
2650 }
2651 
2652 static inline int sk_get_rmem0(const struct sock *sk, const struct proto *proto)
2653 {
2654 	/* Does this proto have per netns sysctl_rmem ? */
2655 	if (proto->sysctl_rmem_offset)
2656 		return *(int *)((void *)sock_net(sk) + proto->sysctl_rmem_offset);
2657 
2658 	return *proto->sysctl_rmem;
2659 }
2660 
2661 /* Default TCP Small queue budget is ~1 ms of data (1sec >> 10)
2662  * Some wifi drivers need to tweak it to get more chunks.
2663  * They can use this helper from their ndo_start_xmit()
2664  */
2665 static inline void sk_pacing_shift_update(struct sock *sk, int val)
2666 {
2667 	if (!sk || !sk_fullsock(sk) || READ_ONCE(sk->sk_pacing_shift) == val)
2668 		return;
2669 	WRITE_ONCE(sk->sk_pacing_shift, val);
2670 }
2671 
2672 /* if a socket is bound to a device, check that the given device
2673  * index is either the same or that the socket is bound to an L3
2674  * master device and the given device index is also enslaved to
2675  * that L3 master
2676  */
2677 static inline bool sk_dev_equal_l3scope(struct sock *sk, int dif)
2678 {
2679 	int mdif;
2680 
2681 	if (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif)
2682 		return true;
2683 
2684 	mdif = l3mdev_master_ifindex_by_index(sock_net(sk), dif);
2685 	if (mdif && mdif == sk->sk_bound_dev_if)
2686 		return true;
2687 
2688 	return false;
2689 }
2690 
2691 void sock_def_readable(struct sock *sk);
2692 
2693 int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk);
2694 void sock_enable_timestamps(struct sock *sk);
2695 void sock_no_linger(struct sock *sk);
2696 void sock_set_keepalive(struct sock *sk);
2697 void sock_set_priority(struct sock *sk, u32 priority);
2698 void sock_set_rcvbuf(struct sock *sk, int val);
2699 void sock_set_mark(struct sock *sk, u32 val);
2700 void sock_set_reuseaddr(struct sock *sk);
2701 void sock_set_reuseport(struct sock *sk);
2702 void sock_set_sndtimeo(struct sock *sk, s64 secs);
2703 
2704 int sock_bind_add(struct sock *sk, struct sockaddr *addr, int addr_len);
2705 
2706 #endif	/* _SOCK_H */
2707