xref: /openbmc/linux/include/net/sock.h (revision 25b892b5)
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 #include <uapi/linux/socket.h>
72 
73 /*
74  * This structure really needs to be cleaned up.
75  * Most of it is for TCP, and not used by any of
76  * the other protocols.
77  */
78 
79 /* Define this to get the SOCK_DBG debugging facility. */
80 #define SOCK_DEBUGGING
81 #ifdef SOCK_DEBUGGING
82 #define SOCK_DEBUG(sk, msg...) do { if ((sk) && sock_flag((sk), SOCK_DBG)) \
83 					printk(KERN_DEBUG msg); } while (0)
84 #else
85 /* Validate arguments and do nothing */
86 static inline __printf(2, 3)
87 void SOCK_DEBUG(const struct sock *sk, const char *msg, ...)
88 {
89 }
90 #endif
91 
92 /* This is the per-socket lock.  The spinlock provides a synchronization
93  * between user contexts and software interrupt processing, whereas the
94  * mini-semaphore synchronizes multiple users amongst themselves.
95  */
96 typedef struct {
97 	spinlock_t		slock;
98 	int			owned;
99 	wait_queue_head_t	wq;
100 	/*
101 	 * We express the mutex-alike socket_lock semantics
102 	 * to the lock validator by explicitly managing
103 	 * the slock as a lock variant (in addition to
104 	 * the slock itself):
105 	 */
106 #ifdef CONFIG_DEBUG_LOCK_ALLOC
107 	struct lockdep_map dep_map;
108 #endif
109 } socket_lock_t;
110 
111 struct sock;
112 struct proto;
113 struct net;
114 
115 typedef __u32 __bitwise __portpair;
116 typedef __u64 __bitwise __addrpair;
117 
118 /**
119  *	struct sock_common - minimal network layer representation of sockets
120  *	@skc_daddr: Foreign IPv4 addr
121  *	@skc_rcv_saddr: Bound local IPv4 addr
122  *	@skc_addrpair: 8-byte-aligned __u64 union of @skc_daddr & @skc_rcv_saddr
123  *	@skc_hash: hash value used with various protocol lookup tables
124  *	@skc_u16hashes: two u16 hash values used by UDP lookup tables
125  *	@skc_dport: placeholder for inet_dport/tw_dport
126  *	@skc_num: placeholder for inet_num/tw_num
127  *	@skc_portpair: __u32 union of @skc_dport & @skc_num
128  *	@skc_family: network address family
129  *	@skc_state: Connection state
130  *	@skc_reuse: %SO_REUSEADDR setting
131  *	@skc_reuseport: %SO_REUSEPORT setting
132  *	@skc_ipv6only: socket is IPV6 only
133  *	@skc_net_refcnt: socket is using net ref counting
134  *	@skc_bound_dev_if: bound device index if != 0
135  *	@skc_bind_node: bind hash linkage for various protocol lookup tables
136  *	@skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
137  *	@skc_prot: protocol handlers inside a network family
138  *	@skc_net: reference to the network namespace of this socket
139  *	@skc_v6_daddr: IPV6 destination address
140  *	@skc_v6_rcv_saddr: IPV6 source address
141  *	@skc_cookie: socket's cookie value
142  *	@skc_node: main hash linkage for various protocol lookup tables
143  *	@skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
144  *	@skc_tx_queue_mapping: tx queue number for this connection
145  *	@skc_rx_queue_mapping: rx queue number for this connection
146  *	@skc_flags: place holder for sk_flags
147  *		%SO_LINGER (l_onoff), %SO_BROADCAST, %SO_KEEPALIVE,
148  *		%SO_OOBINLINE settings, %SO_TIMESTAMPING settings
149  *	@skc_listener: connection request listener socket (aka rsk_listener)
150  *		[union with @skc_flags]
151  *	@skc_tw_dr: (aka tw_dr) ptr to &struct inet_timewait_death_row
152  *		[union with @skc_flags]
153  *	@skc_incoming_cpu: record/match cpu processing incoming packets
154  *	@skc_rcv_wnd: (aka rsk_rcv_wnd) TCP receive window size (possibly scaled)
155  *		[union with @skc_incoming_cpu]
156  *	@skc_tw_rcv_nxt: (aka tw_rcv_nxt) TCP window next expected seq number
157  *		[union with @skc_incoming_cpu]
158  *	@skc_refcnt: reference count
159  *
160  *	This is the minimal network layer representation of sockets, the header
161  *	for struct sock and struct inet_timewait_sock.
162  */
163 struct sock_common {
164 	/* skc_daddr and skc_rcv_saddr must be grouped on a 8 bytes aligned
165 	 * address on 64bit arches : cf INET_MATCH()
166 	 */
167 	union {
168 		__addrpair	skc_addrpair;
169 		struct {
170 			__be32	skc_daddr;
171 			__be32	skc_rcv_saddr;
172 		};
173 	};
174 	union  {
175 		unsigned int	skc_hash;
176 		__u16		skc_u16hashes[2];
177 	};
178 	/* skc_dport && skc_num must be grouped as well */
179 	union {
180 		__portpair	skc_portpair;
181 		struct {
182 			__be16	skc_dport;
183 			__u16	skc_num;
184 		};
185 	};
186 
187 	unsigned short		skc_family;
188 	volatile unsigned char	skc_state;
189 	unsigned char		skc_reuse:4;
190 	unsigned char		skc_reuseport:1;
191 	unsigned char		skc_ipv6only:1;
192 	unsigned char		skc_net_refcnt:1;
193 	int			skc_bound_dev_if;
194 	union {
195 		struct hlist_node	skc_bind_node;
196 		struct hlist_node	skc_portaddr_node;
197 	};
198 	struct proto		*skc_prot;
199 	possible_net_t		skc_net;
200 
201 #if IS_ENABLED(CONFIG_IPV6)
202 	struct in6_addr		skc_v6_daddr;
203 	struct in6_addr		skc_v6_rcv_saddr;
204 #endif
205 
206 	atomic64_t		skc_cookie;
207 
208 	/* following fields are padding to force
209 	 * offset(struct sock, sk_refcnt) == 128 on 64bit arches
210 	 * assuming IPV6 is enabled. We use this padding differently
211 	 * for different kind of 'sockets'
212 	 */
213 	union {
214 		unsigned long	skc_flags;
215 		struct sock	*skc_listener; /* request_sock */
216 		struct inet_timewait_death_row *skc_tw_dr; /* inet_timewait_sock */
217 	};
218 	/*
219 	 * fields between dontcopy_begin/dontcopy_end
220 	 * are not copied in sock_copy()
221 	 */
222 	/* private: */
223 	int			skc_dontcopy_begin[0];
224 	/* public: */
225 	union {
226 		struct hlist_node	skc_node;
227 		struct hlist_nulls_node skc_nulls_node;
228 	};
229 	unsigned short		skc_tx_queue_mapping;
230 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
231 	unsigned short		skc_rx_queue_mapping;
232 #endif
233 	union {
234 		int		skc_incoming_cpu;
235 		u32		skc_rcv_wnd;
236 		u32		skc_tw_rcv_nxt; /* struct tcp_timewait_sock  */
237 	};
238 
239 	refcount_t		skc_refcnt;
240 	/* private: */
241 	int                     skc_dontcopy_end[0];
242 	union {
243 		u32		skc_rxhash;
244 		u32		skc_window_clamp;
245 		u32		skc_tw_snd_nxt; /* struct tcp_timewait_sock */
246 	};
247 	/* public: */
248 };
249 
250 struct bpf_local_storage;
251 
252 /**
253   *	struct sock - network layer representation of sockets
254   *	@__sk_common: shared layout with inet_timewait_sock
255   *	@sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
256   *	@sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
257   *	@sk_lock:	synchronizer
258   *	@sk_kern_sock: True if sock is using kernel lock classes
259   *	@sk_rcvbuf: size of receive buffer in bytes
260   *	@sk_wq: sock wait queue and async head
261   *	@sk_rx_dst: receive input route used by early demux
262   *	@sk_dst_cache: destination cache
263   *	@sk_dst_pending_confirm: need to confirm neighbour
264   *	@sk_policy: flow policy
265   *	@sk_rx_skb_cache: cache copy of recently accessed RX skb
266   *	@sk_receive_queue: incoming packets
267   *	@sk_wmem_alloc: transmit queue bytes committed
268   *	@sk_tsq_flags: TCP Small Queues flags
269   *	@sk_write_queue: Packet sending queue
270   *	@sk_omem_alloc: "o" is "option" or "other"
271   *	@sk_wmem_queued: persistent queue size
272   *	@sk_forward_alloc: space allocated forward
273   *	@sk_napi_id: id of the last napi context to receive data for sk
274   *	@sk_ll_usec: usecs to busypoll when there is no data
275   *	@sk_allocation: allocation mode
276   *	@sk_pacing_rate: Pacing rate (if supported by transport/packet scheduler)
277   *	@sk_pacing_status: Pacing status (requested, handled by sch_fq)
278   *	@sk_max_pacing_rate: Maximum pacing rate (%SO_MAX_PACING_RATE)
279   *	@sk_sndbuf: size of send buffer in bytes
280   *	@__sk_flags_offset: empty field used to determine location of bitfield
281   *	@sk_padding: unused element for alignment
282   *	@sk_no_check_tx: %SO_NO_CHECK setting, set checksum in TX packets
283   *	@sk_no_check_rx: allow zero checksum in RX packets
284   *	@sk_route_caps: route capabilities (e.g. %NETIF_F_TSO)
285   *	@sk_route_nocaps: forbidden route capabilities (e.g NETIF_F_GSO_MASK)
286   *	@sk_route_forced_caps: static, forced route capabilities
287   *		(set in tcp_init_sock())
288   *	@sk_gso_type: GSO type (e.g. %SKB_GSO_TCPV4)
289   *	@sk_gso_max_size: Maximum GSO segment size to build
290   *	@sk_gso_max_segs: Maximum number of GSO segments
291   *	@sk_pacing_shift: scaling factor for TCP Small Queues
292   *	@sk_lingertime: %SO_LINGER l_linger setting
293   *	@sk_backlog: always used with the per-socket spinlock held
294   *	@sk_callback_lock: used with the callbacks in the end of this struct
295   *	@sk_error_queue: rarely used
296   *	@sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt,
297   *			  IPV6_ADDRFORM for instance)
298   *	@sk_err: last error
299   *	@sk_err_soft: errors that don't cause failure but are the cause of a
300   *		      persistent failure not just 'timed out'
301   *	@sk_drops: raw/udp drops counter
302   *	@sk_ack_backlog: current listen backlog
303   *	@sk_max_ack_backlog: listen backlog set in listen()
304   *	@sk_uid: user id of owner
305   *	@sk_prefer_busy_poll: prefer busypolling over softirq processing
306   *	@sk_busy_poll_budget: napi processing budget when busypolling
307   *	@sk_priority: %SO_PRIORITY setting
308   *	@sk_type: socket type (%SOCK_STREAM, etc)
309   *	@sk_protocol: which protocol this socket belongs in this network family
310   *	@sk_peer_pid: &struct pid for this socket's peer
311   *	@sk_peer_cred: %SO_PEERCRED setting
312   *	@sk_rcvlowat: %SO_RCVLOWAT setting
313   *	@sk_rcvtimeo: %SO_RCVTIMEO setting
314   *	@sk_sndtimeo: %SO_SNDTIMEO setting
315   *	@sk_txhash: computed flow hash for use on transmit
316   *	@sk_filter: socket filtering instructions
317   *	@sk_timer: sock cleanup timer
318   *	@sk_stamp: time stamp of last packet received
319   *	@sk_stamp_seq: lock for accessing sk_stamp on 32 bit architectures only
320   *	@sk_tsflags: SO_TIMESTAMPING flags
321   *	@sk_bind_phc: SO_TIMESTAMPING bind PHC index of PTP virtual clock
322   *	              for timestamping
323   *	@sk_tskey: counter to disambiguate concurrent tstamp requests
324   *	@sk_zckey: counter to order MSG_ZEROCOPY notifications
325   *	@sk_socket: Identd and reporting IO signals
326   *	@sk_user_data: RPC layer private data
327   *	@sk_frag: cached page frag
328   *	@sk_peek_off: current peek_offset value
329   *	@sk_send_head: front of stuff to transmit
330   *	@tcp_rtx_queue: TCP re-transmit queue [union with @sk_send_head]
331   *	@sk_tx_skb_cache: cache copy of recently accessed TX skb
332   *	@sk_security: used by security modules
333   *	@sk_mark: generic packet mark
334   *	@sk_cgrp_data: cgroup data for this cgroup
335   *	@sk_memcg: this socket's memory cgroup association
336   *	@sk_write_pending: a write to stream socket waits to start
337   *	@sk_state_change: callback to indicate change in the state of the sock
338   *	@sk_data_ready: callback to indicate there is data to be processed
339   *	@sk_write_space: callback to indicate there is bf sending space available
340   *	@sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE)
341   *	@sk_backlog_rcv: callback to process the backlog
342   *	@sk_validate_xmit_skb: ptr to an optional validate function
343   *	@sk_destruct: called at sock freeing time, i.e. when all refcnt == 0
344   *	@sk_reuseport_cb: reuseport group container
345   *	@sk_bpf_storage: ptr to cache and control for bpf_sk_storage
346   *	@sk_rcu: used during RCU grace period
347   *	@sk_clockid: clockid used by time-based scheduling (SO_TXTIME)
348   *	@sk_txtime_deadline_mode: set deadline mode for SO_TXTIME
349   *	@sk_txtime_report_errors: set report errors mode for SO_TXTIME
350   *	@sk_txtime_unused: unused txtime flags
351   */
352 struct sock {
353 	/*
354 	 * Now struct inet_timewait_sock also uses sock_common, so please just
355 	 * don't add nothing before this first member (__sk_common) --acme
356 	 */
357 	struct sock_common	__sk_common;
358 #define sk_node			__sk_common.skc_node
359 #define sk_nulls_node		__sk_common.skc_nulls_node
360 #define sk_refcnt		__sk_common.skc_refcnt
361 #define sk_tx_queue_mapping	__sk_common.skc_tx_queue_mapping
362 #ifdef CONFIG_SOCK_RX_QUEUE_MAPPING
363 #define sk_rx_queue_mapping	__sk_common.skc_rx_queue_mapping
364 #endif
365 
366 #define sk_dontcopy_begin	__sk_common.skc_dontcopy_begin
367 #define sk_dontcopy_end		__sk_common.skc_dontcopy_end
368 #define sk_hash			__sk_common.skc_hash
369 #define sk_portpair		__sk_common.skc_portpair
370 #define sk_num			__sk_common.skc_num
371 #define sk_dport		__sk_common.skc_dport
372 #define sk_addrpair		__sk_common.skc_addrpair
373 #define sk_daddr		__sk_common.skc_daddr
374 #define sk_rcv_saddr		__sk_common.skc_rcv_saddr
375 #define sk_family		__sk_common.skc_family
376 #define sk_state		__sk_common.skc_state
377 #define sk_reuse		__sk_common.skc_reuse
378 #define sk_reuseport		__sk_common.skc_reuseport
379 #define sk_ipv6only		__sk_common.skc_ipv6only
380 #define sk_net_refcnt		__sk_common.skc_net_refcnt
381 #define sk_bound_dev_if		__sk_common.skc_bound_dev_if
382 #define sk_bind_node		__sk_common.skc_bind_node
383 #define sk_prot			__sk_common.skc_prot
384 #define sk_net			__sk_common.skc_net
385 #define sk_v6_daddr		__sk_common.skc_v6_daddr
386 #define sk_v6_rcv_saddr	__sk_common.skc_v6_rcv_saddr
387 #define sk_cookie		__sk_common.skc_cookie
388 #define sk_incoming_cpu		__sk_common.skc_incoming_cpu
389 #define sk_flags		__sk_common.skc_flags
390 #define sk_rxhash		__sk_common.skc_rxhash
391 
392 	socket_lock_t		sk_lock;
393 	atomic_t		sk_drops;
394 	int			sk_rcvlowat;
395 	struct sk_buff_head	sk_error_queue;
396 	struct sk_buff		*sk_rx_skb_cache;
397 	struct sk_buff_head	sk_receive_queue;
398 	/*
399 	 * The backlog queue is special, it is always used with
400 	 * the per-socket spinlock held and requires low latency
401 	 * access. Therefore we special case it's implementation.
402 	 * Note : rmem_alloc is in this structure to fill a hole
403 	 * on 64bit arches, not because its logically part of
404 	 * backlog.
405 	 */
406 	struct {
407 		atomic_t	rmem_alloc;
408 		int		len;
409 		struct sk_buff	*head;
410 		struct sk_buff	*tail;
411 	} sk_backlog;
412 #define sk_rmem_alloc sk_backlog.rmem_alloc
413 
414 	int			sk_forward_alloc;
415 #ifdef CONFIG_NET_RX_BUSY_POLL
416 	unsigned int		sk_ll_usec;
417 	/* ===== mostly read cache line ===== */
418 	unsigned int		sk_napi_id;
419 #endif
420 	int			sk_rcvbuf;
421 
422 	struct sk_filter __rcu	*sk_filter;
423 	union {
424 		struct socket_wq __rcu	*sk_wq;
425 		/* private: */
426 		struct socket_wq	*sk_wq_raw;
427 		/* public: */
428 	};
429 #ifdef CONFIG_XFRM
430 	struct xfrm_policy __rcu *sk_policy[2];
431 #endif
432 	struct dst_entry	*sk_rx_dst;
433 	struct dst_entry __rcu	*sk_dst_cache;
434 	atomic_t		sk_omem_alloc;
435 	int			sk_sndbuf;
436 
437 	/* ===== cache line for TX ===== */
438 	int			sk_wmem_queued;
439 	refcount_t		sk_wmem_alloc;
440 	unsigned long		sk_tsq_flags;
441 	union {
442 		struct sk_buff	*sk_send_head;
443 		struct rb_root	tcp_rtx_queue;
444 	};
445 	struct sk_buff		*sk_tx_skb_cache;
446 	struct sk_buff_head	sk_write_queue;
447 	__s32			sk_peek_off;
448 	int			sk_write_pending;
449 	__u32			sk_dst_pending_confirm;
450 	u32			sk_pacing_status; /* see enum sk_pacing */
451 	long			sk_sndtimeo;
452 	struct timer_list	sk_timer;
453 	__u32			sk_priority;
454 	__u32			sk_mark;
455 	unsigned long		sk_pacing_rate; /* bytes per second */
456 	unsigned long		sk_max_pacing_rate;
457 	struct page_frag	sk_frag;
458 	netdev_features_t	sk_route_caps;
459 	netdev_features_t	sk_route_nocaps;
460 	netdev_features_t	sk_route_forced_caps;
461 	int			sk_gso_type;
462 	unsigned int		sk_gso_max_size;
463 	gfp_t			sk_allocation;
464 	__u32			sk_txhash;
465 
466 	/*
467 	 * Because of non atomicity rules, all
468 	 * changes are protected by socket lock.
469 	 */
470 	u8			sk_padding : 1,
471 				sk_kern_sock : 1,
472 				sk_no_check_tx : 1,
473 				sk_no_check_rx : 1,
474 				sk_userlocks : 4;
475 	u8			sk_pacing_shift;
476 	u16			sk_type;
477 	u16			sk_protocol;
478 	u16			sk_gso_max_segs;
479 	unsigned long	        sk_lingertime;
480 	struct proto		*sk_prot_creator;
481 	rwlock_t		sk_callback_lock;
482 	int			sk_err,
483 				sk_err_soft;
484 	u32			sk_ack_backlog;
485 	u32			sk_max_ack_backlog;
486 	kuid_t			sk_uid;
487 #ifdef CONFIG_NET_RX_BUSY_POLL
488 	u8			sk_prefer_busy_poll;
489 	u16			sk_busy_poll_budget;
490 #endif
491 	struct pid		*sk_peer_pid;
492 	const struct cred	*sk_peer_cred;
493 	long			sk_rcvtimeo;
494 	ktime_t			sk_stamp;
495 #if BITS_PER_LONG==32
496 	seqlock_t		sk_stamp_seq;
497 #endif
498 	u16			sk_tsflags;
499 	int			sk_bind_phc;
500 	u8			sk_shutdown;
501 	u32			sk_tskey;
502 	atomic_t		sk_zckey;
503 
504 	u8			sk_clockid;
505 	u8			sk_txtime_deadline_mode : 1,
506 				sk_txtime_report_errors : 1,
507 				sk_txtime_unused : 6;
508 
509 	struct socket		*sk_socket;
510 	void			*sk_user_data;
511 #ifdef CONFIG_SECURITY
512 	void			*sk_security;
513 #endif
514 	struct sock_cgroup_data	sk_cgrp_data;
515 	struct mem_cgroup	*sk_memcg;
516 	void			(*sk_state_change)(struct sock *sk);
517 	void			(*sk_data_ready)(struct sock *sk);
518 	void			(*sk_write_space)(struct sock *sk);
519 	void			(*sk_error_report)(struct sock *sk);
520 	int			(*sk_backlog_rcv)(struct sock *sk,
521 						  struct sk_buff *skb);
522 #ifdef CONFIG_SOCK_VALIDATE_XMIT
523 	struct sk_buff*		(*sk_validate_xmit_skb)(struct sock *sk,
524 							struct net_device *dev,
525 							struct sk_buff *skb);
526 #endif
527 	void                    (*sk_destruct)(struct sock *sk);
528 	struct sock_reuseport __rcu	*sk_reuseport_cb;
529 #ifdef CONFIG_BPF_SYSCALL
530 	struct bpf_local_storage __rcu	*sk_bpf_storage;
531 #endif
532 	struct rcu_head		sk_rcu;
533 };
534 
535 enum sk_pacing {
536 	SK_PACING_NONE		= 0,
537 	SK_PACING_NEEDED	= 1,
538 	SK_PACING_FQ		= 2,
539 };
540 
541 /* Pointer stored in sk_user_data might not be suitable for copying
542  * when cloning the socket. For instance, it can point to a reference
543  * counted object. sk_user_data bottom bit is set if pointer must not
544  * be copied.
545  */
546 #define SK_USER_DATA_NOCOPY	1UL
547 #define SK_USER_DATA_BPF	2UL	/* Managed by BPF */
548 #define SK_USER_DATA_PTRMASK	~(SK_USER_DATA_NOCOPY | SK_USER_DATA_BPF)
549 
550 /**
551  * sk_user_data_is_nocopy - Test if sk_user_data pointer must not be copied
552  * @sk: socket
553  */
554 static inline bool sk_user_data_is_nocopy(const struct sock *sk)
555 {
556 	return ((uintptr_t)sk->sk_user_data & SK_USER_DATA_NOCOPY);
557 }
558 
559 #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data)))
560 
561 #define rcu_dereference_sk_user_data(sk)				\
562 ({									\
563 	void *__tmp = rcu_dereference(__sk_user_data((sk)));		\
564 	(void *)((uintptr_t)__tmp & SK_USER_DATA_PTRMASK);		\
565 })
566 #define rcu_assign_sk_user_data(sk, ptr)				\
567 ({									\
568 	uintptr_t __tmp = (uintptr_t)(ptr);				\
569 	WARN_ON_ONCE(__tmp & ~SK_USER_DATA_PTRMASK);			\
570 	rcu_assign_pointer(__sk_user_data((sk)), __tmp);		\
571 })
572 #define rcu_assign_sk_user_data_nocopy(sk, ptr)				\
573 ({									\
574 	uintptr_t __tmp = (uintptr_t)(ptr);				\
575 	WARN_ON_ONCE(__tmp & ~SK_USER_DATA_PTRMASK);			\
576 	rcu_assign_pointer(__sk_user_data((sk)),			\
577 			   __tmp | SK_USER_DATA_NOCOPY);		\
578 })
579 
580 /*
581  * SK_CAN_REUSE and SK_NO_REUSE on a socket mean that the socket is OK
582  * or not whether his port will be reused by someone else. SK_FORCE_REUSE
583  * on a socket means that the socket will reuse everybody else's port
584  * without looking at the other's sk_reuse value.
585  */
586 
587 #define SK_NO_REUSE	0
588 #define SK_CAN_REUSE	1
589 #define SK_FORCE_REUSE	2
590 
591 int sk_set_peek_off(struct sock *sk, int val);
592 
593 static inline int sk_peek_offset(struct sock *sk, int flags)
594 {
595 	if (unlikely(flags & MSG_PEEK)) {
596 		return READ_ONCE(sk->sk_peek_off);
597 	}
598 
599 	return 0;
600 }
601 
602 static inline void sk_peek_offset_bwd(struct sock *sk, int val)
603 {
604 	s32 off = READ_ONCE(sk->sk_peek_off);
605 
606 	if (unlikely(off >= 0)) {
607 		off = max_t(s32, off - val, 0);
608 		WRITE_ONCE(sk->sk_peek_off, off);
609 	}
610 }
611 
612 static inline void sk_peek_offset_fwd(struct sock *sk, int val)
613 {
614 	sk_peek_offset_bwd(sk, -val);
615 }
616 
617 /*
618  * Hashed lists helper routines
619  */
620 static inline struct sock *sk_entry(const struct hlist_node *node)
621 {
622 	return hlist_entry(node, struct sock, sk_node);
623 }
624 
625 static inline struct sock *__sk_head(const struct hlist_head *head)
626 {
627 	return hlist_entry(head->first, struct sock, sk_node);
628 }
629 
630 static inline struct sock *sk_head(const struct hlist_head *head)
631 {
632 	return hlist_empty(head) ? NULL : __sk_head(head);
633 }
634 
635 static inline struct sock *__sk_nulls_head(const struct hlist_nulls_head *head)
636 {
637 	return hlist_nulls_entry(head->first, struct sock, sk_nulls_node);
638 }
639 
640 static inline struct sock *sk_nulls_head(const struct hlist_nulls_head *head)
641 {
642 	return hlist_nulls_empty(head) ? NULL : __sk_nulls_head(head);
643 }
644 
645 static inline struct sock *sk_next(const struct sock *sk)
646 {
647 	return hlist_entry_safe(sk->sk_node.next, struct sock, sk_node);
648 }
649 
650 static inline struct sock *sk_nulls_next(const struct sock *sk)
651 {
652 	return (!is_a_nulls(sk->sk_nulls_node.next)) ?
653 		hlist_nulls_entry(sk->sk_nulls_node.next,
654 				  struct sock, sk_nulls_node) :
655 		NULL;
656 }
657 
658 static inline bool sk_unhashed(const struct sock *sk)
659 {
660 	return hlist_unhashed(&sk->sk_node);
661 }
662 
663 static inline bool sk_hashed(const struct sock *sk)
664 {
665 	return !sk_unhashed(sk);
666 }
667 
668 static inline void sk_node_init(struct hlist_node *node)
669 {
670 	node->pprev = NULL;
671 }
672 
673 static inline void sk_nulls_node_init(struct hlist_nulls_node *node)
674 {
675 	node->pprev = NULL;
676 }
677 
678 static inline void __sk_del_node(struct sock *sk)
679 {
680 	__hlist_del(&sk->sk_node);
681 }
682 
683 /* NB: equivalent to hlist_del_init_rcu */
684 static inline bool __sk_del_node_init(struct sock *sk)
685 {
686 	if (sk_hashed(sk)) {
687 		__sk_del_node(sk);
688 		sk_node_init(&sk->sk_node);
689 		return true;
690 	}
691 	return false;
692 }
693 
694 /* Grab socket reference count. This operation is valid only
695    when sk is ALREADY grabbed f.e. it is found in hash table
696    or a list and the lookup is made under lock preventing hash table
697    modifications.
698  */
699 
700 static __always_inline void sock_hold(struct sock *sk)
701 {
702 	refcount_inc(&sk->sk_refcnt);
703 }
704 
705 /* Ungrab socket in the context, which assumes that socket refcnt
706    cannot hit zero, f.e. it is true in context of any socketcall.
707  */
708 static __always_inline void __sock_put(struct sock *sk)
709 {
710 	refcount_dec(&sk->sk_refcnt);
711 }
712 
713 static inline bool sk_del_node_init(struct sock *sk)
714 {
715 	bool rc = __sk_del_node_init(sk);
716 
717 	if (rc) {
718 		/* paranoid for a while -acme */
719 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
720 		__sock_put(sk);
721 	}
722 	return rc;
723 }
724 #define sk_del_node_init_rcu(sk)	sk_del_node_init(sk)
725 
726 static inline bool __sk_nulls_del_node_init_rcu(struct sock *sk)
727 {
728 	if (sk_hashed(sk)) {
729 		hlist_nulls_del_init_rcu(&sk->sk_nulls_node);
730 		return true;
731 	}
732 	return false;
733 }
734 
735 static inline bool sk_nulls_del_node_init_rcu(struct sock *sk)
736 {
737 	bool rc = __sk_nulls_del_node_init_rcu(sk);
738 
739 	if (rc) {
740 		/* paranoid for a while -acme */
741 		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
742 		__sock_put(sk);
743 	}
744 	return rc;
745 }
746 
747 static inline void __sk_add_node(struct sock *sk, struct hlist_head *list)
748 {
749 	hlist_add_head(&sk->sk_node, list);
750 }
751 
752 static inline void sk_add_node(struct sock *sk, struct hlist_head *list)
753 {
754 	sock_hold(sk);
755 	__sk_add_node(sk, list);
756 }
757 
758 static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
759 {
760 	sock_hold(sk);
761 	if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
762 	    sk->sk_family == AF_INET6)
763 		hlist_add_tail_rcu(&sk->sk_node, list);
764 	else
765 		hlist_add_head_rcu(&sk->sk_node, list);
766 }
767 
768 static inline void sk_add_node_tail_rcu(struct sock *sk, struct hlist_head *list)
769 {
770 	sock_hold(sk);
771 	hlist_add_tail_rcu(&sk->sk_node, list);
772 }
773 
774 static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
775 {
776 	hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
777 }
778 
779 static inline void __sk_nulls_add_node_tail_rcu(struct sock *sk, struct hlist_nulls_head *list)
780 {
781 	hlist_nulls_add_tail_rcu(&sk->sk_nulls_node, list);
782 }
783 
784 static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
785 {
786 	sock_hold(sk);
787 	__sk_nulls_add_node_rcu(sk, list);
788 }
789 
790 static inline void __sk_del_bind_node(struct sock *sk)
791 {
792 	__hlist_del(&sk->sk_bind_node);
793 }
794 
795 static inline void sk_add_bind_node(struct sock *sk,
796 					struct hlist_head *list)
797 {
798 	hlist_add_head(&sk->sk_bind_node, list);
799 }
800 
801 #define sk_for_each(__sk, list) \
802 	hlist_for_each_entry(__sk, list, sk_node)
803 #define sk_for_each_rcu(__sk, list) \
804 	hlist_for_each_entry_rcu(__sk, list, sk_node)
805 #define sk_nulls_for_each(__sk, node, list) \
806 	hlist_nulls_for_each_entry(__sk, node, list, sk_nulls_node)
807 #define sk_nulls_for_each_rcu(__sk, node, list) \
808 	hlist_nulls_for_each_entry_rcu(__sk, node, list, sk_nulls_node)
809 #define sk_for_each_from(__sk) \
810 	hlist_for_each_entry_from(__sk, sk_node)
811 #define sk_nulls_for_each_from(__sk, node) \
812 	if (__sk && ({ node = &(__sk)->sk_nulls_node; 1; })) \
813 		hlist_nulls_for_each_entry_from(__sk, node, sk_nulls_node)
814 #define sk_for_each_safe(__sk, tmp, list) \
815 	hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
816 #define sk_for_each_bound(__sk, list) \
817 	hlist_for_each_entry(__sk, list, sk_bind_node)
818 
819 /**
820  * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset
821  * @tpos:	the type * to use as a loop cursor.
822  * @pos:	the &struct hlist_node to use as a loop cursor.
823  * @head:	the head for your list.
824  * @offset:	offset of hlist_node within the struct.
825  *
826  */
827 #define sk_for_each_entry_offset_rcu(tpos, pos, head, offset)		       \
828 	for (pos = rcu_dereference(hlist_first_rcu(head));		       \
829 	     pos != NULL &&						       \
830 		({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \
831 	     pos = rcu_dereference(hlist_next_rcu(pos)))
832 
833 static inline struct user_namespace *sk_user_ns(struct sock *sk)
834 {
835 	/* Careful only use this in a context where these parameters
836 	 * can not change and must all be valid, such as recvmsg from
837 	 * userspace.
838 	 */
839 	return sk->sk_socket->file->f_cred->user_ns;
840 }
841 
842 /* Sock flags */
843 enum sock_flags {
844 	SOCK_DEAD,
845 	SOCK_DONE,
846 	SOCK_URGINLINE,
847 	SOCK_KEEPOPEN,
848 	SOCK_LINGER,
849 	SOCK_DESTROY,
850 	SOCK_BROADCAST,
851 	SOCK_TIMESTAMP,
852 	SOCK_ZAPPED,
853 	SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
854 	SOCK_DBG, /* %SO_DEBUG setting */
855 	SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
856 	SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
857 	SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
858 	SOCK_MEMALLOC, /* VM depends on this socket for swapping */
859 	SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
860 	SOCK_FASYNC, /* fasync() active */
861 	SOCK_RXQ_OVFL,
862 	SOCK_ZEROCOPY, /* buffers from userspace */
863 	SOCK_WIFI_STATUS, /* push wifi status to userspace */
864 	SOCK_NOFCS, /* Tell NIC not to do the Ethernet FCS.
865 		     * Will use last 4 bytes of packet sent from
866 		     * user-space instead.
867 		     */
868 	SOCK_FILTER_LOCKED, /* Filter cannot be changed anymore */
869 	SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
870 	SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
871 	SOCK_TXTIME,
872 	SOCK_XDP, /* XDP is attached */
873 	SOCK_TSTAMP_NEW, /* Indicates 64 bit timestamps always */
874 };
875 
876 #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
877 
878 static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
879 {
880 	nsk->sk_flags = osk->sk_flags;
881 }
882 
883 static inline void sock_set_flag(struct sock *sk, enum sock_flags flag)
884 {
885 	__set_bit(flag, &sk->sk_flags);
886 }
887 
888 static inline void sock_reset_flag(struct sock *sk, enum sock_flags flag)
889 {
890 	__clear_bit(flag, &sk->sk_flags);
891 }
892 
893 static inline void sock_valbool_flag(struct sock *sk, enum sock_flags bit,
894 				     int valbool)
895 {
896 	if (valbool)
897 		sock_set_flag(sk, bit);
898 	else
899 		sock_reset_flag(sk, bit);
900 }
901 
902 static inline bool sock_flag(const struct sock *sk, enum sock_flags flag)
903 {
904 	return test_bit(flag, &sk->sk_flags);
905 }
906 
907 #ifdef CONFIG_NET
908 DECLARE_STATIC_KEY_FALSE(memalloc_socks_key);
909 static inline int sk_memalloc_socks(void)
910 {
911 	return static_branch_unlikely(&memalloc_socks_key);
912 }
913 
914 void __receive_sock(struct file *file);
915 #else
916 
917 static inline int sk_memalloc_socks(void)
918 {
919 	return 0;
920 }
921 
922 static inline void __receive_sock(struct file *file)
923 { }
924 #endif
925 
926 static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)
927 {
928 	return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);
929 }
930 
931 static inline void sk_acceptq_removed(struct sock *sk)
932 {
933 	WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog - 1);
934 }
935 
936 static inline void sk_acceptq_added(struct sock *sk)
937 {
938 	WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog + 1);
939 }
940 
941 /* Note: If you think the test should be:
942  *	return READ_ONCE(sk->sk_ack_backlog) >= READ_ONCE(sk->sk_max_ack_backlog);
943  * Then please take a look at commit 64a146513f8f ("[NET]: Revert incorrect accept queue backlog changes.")
944  */
945 static inline bool sk_acceptq_is_full(const struct sock *sk)
946 {
947 	return READ_ONCE(sk->sk_ack_backlog) > READ_ONCE(sk->sk_max_ack_backlog);
948 }
949 
950 /*
951  * Compute minimal free write space needed to queue new packets.
952  */
953 static inline int sk_stream_min_wspace(const struct sock *sk)
954 {
955 	return READ_ONCE(sk->sk_wmem_queued) >> 1;
956 }
957 
958 static inline int sk_stream_wspace(const struct sock *sk)
959 {
960 	return READ_ONCE(sk->sk_sndbuf) - READ_ONCE(sk->sk_wmem_queued);
961 }
962 
963 static inline void sk_wmem_queued_add(struct sock *sk, int val)
964 {
965 	WRITE_ONCE(sk->sk_wmem_queued, sk->sk_wmem_queued + val);
966 }
967 
968 void sk_stream_write_space(struct sock *sk);
969 
970 /* OOB backlog add */
971 static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb)
972 {
973 	/* dont let skb dst not refcounted, we are going to leave rcu lock */
974 	skb_dst_force(skb);
975 
976 	if (!sk->sk_backlog.tail)
977 		WRITE_ONCE(sk->sk_backlog.head, skb);
978 	else
979 		sk->sk_backlog.tail->next = skb;
980 
981 	WRITE_ONCE(sk->sk_backlog.tail, skb);
982 	skb->next = NULL;
983 }
984 
985 /*
986  * Take into account size of receive queue and backlog queue
987  * Do not take into account this skb truesize,
988  * to allow even a single big packet to come.
989  */
990 static inline bool sk_rcvqueues_full(const struct sock *sk, unsigned int limit)
991 {
992 	unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);
993 
994 	return qsize > limit;
995 }
996 
997 /* The per-socket spinlock must be held here. */
998 static inline __must_check int sk_add_backlog(struct sock *sk, struct sk_buff *skb,
999 					      unsigned int limit)
1000 {
1001 	if (sk_rcvqueues_full(sk, limit))
1002 		return -ENOBUFS;
1003 
1004 	/*
1005 	 * If the skb was allocated from pfmemalloc reserves, only
1006 	 * allow SOCK_MEMALLOC sockets to use it as this socket is
1007 	 * helping free memory
1008 	 */
1009 	if (skb_pfmemalloc(skb) && !sock_flag(sk, SOCK_MEMALLOC))
1010 		return -ENOMEM;
1011 
1012 	__sk_add_backlog(sk, skb);
1013 	sk->sk_backlog.len += skb->truesize;
1014 	return 0;
1015 }
1016 
1017 int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb);
1018 
1019 static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb)
1020 {
1021 	if (sk_memalloc_socks() && skb_pfmemalloc(skb))
1022 		return __sk_backlog_rcv(sk, skb);
1023 
1024 	return sk->sk_backlog_rcv(sk, skb);
1025 }
1026 
1027 static inline void sk_incoming_cpu_update(struct sock *sk)
1028 {
1029 	int cpu = raw_smp_processor_id();
1030 
1031 	if (unlikely(READ_ONCE(sk->sk_incoming_cpu) != cpu))
1032 		WRITE_ONCE(sk->sk_incoming_cpu, cpu);
1033 }
1034 
1035 static inline void sock_rps_record_flow_hash(__u32 hash)
1036 {
1037 #ifdef CONFIG_RPS
1038 	struct rps_sock_flow_table *sock_flow_table;
1039 
1040 	rcu_read_lock();
1041 	sock_flow_table = rcu_dereference(rps_sock_flow_table);
1042 	rps_record_sock_flow(sock_flow_table, hash);
1043 	rcu_read_unlock();
1044 #endif
1045 }
1046 
1047 static inline void sock_rps_record_flow(const struct sock *sk)
1048 {
1049 #ifdef CONFIG_RPS
1050 	if (static_branch_unlikely(&rfs_needed)) {
1051 		/* Reading sk->sk_rxhash might incur an expensive cache line
1052 		 * miss.
1053 		 *
1054 		 * TCP_ESTABLISHED does cover almost all states where RFS
1055 		 * might be useful, and is cheaper [1] than testing :
1056 		 *	IPv4: inet_sk(sk)->inet_daddr
1057 		 * 	IPv6: ipv6_addr_any(&sk->sk_v6_daddr)
1058 		 * OR	an additional socket flag
1059 		 * [1] : sk_state and sk_prot are in the same cache line.
1060 		 */
1061 		if (sk->sk_state == TCP_ESTABLISHED)
1062 			sock_rps_record_flow_hash(sk->sk_rxhash);
1063 	}
1064 #endif
1065 }
1066 
1067 static inline void sock_rps_save_rxhash(struct sock *sk,
1068 					const struct sk_buff *skb)
1069 {
1070 #ifdef CONFIG_RPS
1071 	if (unlikely(sk->sk_rxhash != skb->hash))
1072 		sk->sk_rxhash = skb->hash;
1073 #endif
1074 }
1075 
1076 static inline void sock_rps_reset_rxhash(struct sock *sk)
1077 {
1078 #ifdef CONFIG_RPS
1079 	sk->sk_rxhash = 0;
1080 #endif
1081 }
1082 
1083 #define sk_wait_event(__sk, __timeo, __condition, __wait)		\
1084 	({	int __rc;						\
1085 		release_sock(__sk);					\
1086 		__rc = __condition;					\
1087 		if (!__rc) {						\
1088 			*(__timeo) = wait_woken(__wait,			\
1089 						TASK_INTERRUPTIBLE,	\
1090 						*(__timeo));		\
1091 		}							\
1092 		sched_annotate_sleep();					\
1093 		lock_sock(__sk);					\
1094 		__rc = __condition;					\
1095 		__rc;							\
1096 	})
1097 
1098 int sk_stream_wait_connect(struct sock *sk, long *timeo_p);
1099 int sk_stream_wait_memory(struct sock *sk, long *timeo_p);
1100 void sk_stream_wait_close(struct sock *sk, long timeo_p);
1101 int sk_stream_error(struct sock *sk, int flags, int err);
1102 void sk_stream_kill_queues(struct sock *sk);
1103 void sk_set_memalloc(struct sock *sk);
1104 void sk_clear_memalloc(struct sock *sk);
1105 
1106 void __sk_flush_backlog(struct sock *sk);
1107 
1108 static inline bool sk_flush_backlog(struct sock *sk)
1109 {
1110 	if (unlikely(READ_ONCE(sk->sk_backlog.tail))) {
1111 		__sk_flush_backlog(sk);
1112 		return true;
1113 	}
1114 	return false;
1115 }
1116 
1117 int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb);
1118 
1119 struct request_sock_ops;
1120 struct timewait_sock_ops;
1121 struct inet_hashinfo;
1122 struct raw_hashinfo;
1123 struct smc_hashinfo;
1124 struct module;
1125 struct sk_psock;
1126 
1127 /*
1128  * caches using SLAB_TYPESAFE_BY_RCU should let .next pointer from nulls nodes
1129  * un-modified. Special care is taken when initializing object to zero.
1130  */
1131 static inline void sk_prot_clear_nulls(struct sock *sk, int size)
1132 {
1133 	if (offsetof(struct sock, sk_node.next) != 0)
1134 		memset(sk, 0, offsetof(struct sock, sk_node.next));
1135 	memset(&sk->sk_node.pprev, 0,
1136 	       size - offsetof(struct sock, sk_node.pprev));
1137 }
1138 
1139 /* Networking protocol blocks we attach to sockets.
1140  * socket layer -> transport layer interface
1141  */
1142 struct proto {
1143 	void			(*close)(struct sock *sk,
1144 					long timeout);
1145 	int			(*pre_connect)(struct sock *sk,
1146 					struct sockaddr *uaddr,
1147 					int addr_len);
1148 	int			(*connect)(struct sock *sk,
1149 					struct sockaddr *uaddr,
1150 					int addr_len);
1151 	int			(*disconnect)(struct sock *sk, int flags);
1152 
1153 	struct sock *		(*accept)(struct sock *sk, int flags, int *err,
1154 					  bool kern);
1155 
1156 	int			(*ioctl)(struct sock *sk, int cmd,
1157 					 unsigned long arg);
1158 	int			(*init)(struct sock *sk);
1159 	void			(*destroy)(struct sock *sk);
1160 	void			(*shutdown)(struct sock *sk, int how);
1161 	int			(*setsockopt)(struct sock *sk, int level,
1162 					int optname, sockptr_t optval,
1163 					unsigned int optlen);
1164 	int			(*getsockopt)(struct sock *sk, int level,
1165 					int optname, char __user *optval,
1166 					int __user *option);
1167 	void			(*keepalive)(struct sock *sk, int valbool);
1168 #ifdef CONFIG_COMPAT
1169 	int			(*compat_ioctl)(struct sock *sk,
1170 					unsigned int cmd, unsigned long arg);
1171 #endif
1172 	int			(*sendmsg)(struct sock *sk, struct msghdr *msg,
1173 					   size_t len);
1174 	int			(*recvmsg)(struct sock *sk, struct msghdr *msg,
1175 					   size_t len, int noblock, int flags,
1176 					   int *addr_len);
1177 	int			(*sendpage)(struct sock *sk, struct page *page,
1178 					int offset, size_t size, int flags);
1179 	int			(*bind)(struct sock *sk,
1180 					struct sockaddr *addr, int addr_len);
1181 	int			(*bind_add)(struct sock *sk,
1182 					struct sockaddr *addr, int addr_len);
1183 
1184 	int			(*backlog_rcv) (struct sock *sk,
1185 						struct sk_buff *skb);
1186 	bool			(*bpf_bypass_getsockopt)(int level,
1187 							 int optname);
1188 
1189 	void		(*release_cb)(struct sock *sk);
1190 
1191 	/* Keeping track of sk's, looking them up, and port selection methods. */
1192 	int			(*hash)(struct sock *sk);
1193 	void			(*unhash)(struct sock *sk);
1194 	void			(*rehash)(struct sock *sk);
1195 	int			(*get_port)(struct sock *sk, unsigned short snum);
1196 #ifdef CONFIG_BPF_SYSCALL
1197 	int			(*psock_update_sk_prot)(struct sock *sk,
1198 							struct sk_psock *psock,
1199 							bool restore);
1200 #endif
1201 
1202 	/* Keeping track of sockets in use */
1203 #ifdef CONFIG_PROC_FS
1204 	unsigned int		inuse_idx;
1205 #endif
1206 
1207 	bool			(*stream_memory_free)(const struct sock *sk, int wake);
1208 	bool			(*stream_memory_read)(const struct sock *sk);
1209 	/* Memory pressure */
1210 	void			(*enter_memory_pressure)(struct sock *sk);
1211 	void			(*leave_memory_pressure)(struct sock *sk);
1212 	atomic_long_t		*memory_allocated;	/* Current allocated memory. */
1213 	struct percpu_counter	*sockets_allocated;	/* Current number of sockets. */
1214 	/*
1215 	 * Pressure flag: try to collapse.
1216 	 * Technical note: it is used by multiple contexts non atomically.
1217 	 * All the __sk_mem_schedule() is of this nature: accounting
1218 	 * is strict, actions are advisory and have some latency.
1219 	 */
1220 	unsigned long		*memory_pressure;
1221 	long			*sysctl_mem;
1222 
1223 	int			*sysctl_wmem;
1224 	int			*sysctl_rmem;
1225 	u32			sysctl_wmem_offset;
1226 	u32			sysctl_rmem_offset;
1227 
1228 	int			max_header;
1229 	bool			no_autobind;
1230 
1231 	struct kmem_cache	*slab;
1232 	unsigned int		obj_size;
1233 	slab_flags_t		slab_flags;
1234 	unsigned int		useroffset;	/* Usercopy region offset */
1235 	unsigned int		usersize;	/* Usercopy region size */
1236 
1237 	struct percpu_counter	*orphan_count;
1238 
1239 	struct request_sock_ops	*rsk_prot;
1240 	struct timewait_sock_ops *twsk_prot;
1241 
1242 	union {
1243 		struct inet_hashinfo	*hashinfo;
1244 		struct udp_table	*udp_table;
1245 		struct raw_hashinfo	*raw_hash;
1246 		struct smc_hashinfo	*smc_hash;
1247 	} h;
1248 
1249 	struct module		*owner;
1250 
1251 	char			name[32];
1252 
1253 	struct list_head	node;
1254 #ifdef SOCK_REFCNT_DEBUG
1255 	atomic_t		socks;
1256 #endif
1257 	int			(*diag_destroy)(struct sock *sk, int err);
1258 } __randomize_layout;
1259 
1260 int proto_register(struct proto *prot, int alloc_slab);
1261 void proto_unregister(struct proto *prot);
1262 int sock_load_diag_module(int family, int protocol);
1263 
1264 #ifdef SOCK_REFCNT_DEBUG
1265 static inline void sk_refcnt_debug_inc(struct sock *sk)
1266 {
1267 	atomic_inc(&sk->sk_prot->socks);
1268 }
1269 
1270 static inline void sk_refcnt_debug_dec(struct sock *sk)
1271 {
1272 	atomic_dec(&sk->sk_prot->socks);
1273 	printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
1274 	       sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
1275 }
1276 
1277 static inline void sk_refcnt_debug_release(const struct sock *sk)
1278 {
1279 	if (refcount_read(&sk->sk_refcnt) != 1)
1280 		printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
1281 		       sk->sk_prot->name, sk, refcount_read(&sk->sk_refcnt));
1282 }
1283 #else /* SOCK_REFCNT_DEBUG */
1284 #define sk_refcnt_debug_inc(sk) do { } while (0)
1285 #define sk_refcnt_debug_dec(sk) do { } while (0)
1286 #define sk_refcnt_debug_release(sk) do { } while (0)
1287 #endif /* SOCK_REFCNT_DEBUG */
1288 
1289 INDIRECT_CALLABLE_DECLARE(bool tcp_stream_memory_free(const struct sock *sk, int wake));
1290 
1291 static inline bool __sk_stream_memory_free(const struct sock *sk, int wake)
1292 {
1293 	if (READ_ONCE(sk->sk_wmem_queued) >= READ_ONCE(sk->sk_sndbuf))
1294 		return false;
1295 
1296 #ifdef CONFIG_INET
1297 	return sk->sk_prot->stream_memory_free ?
1298 		INDIRECT_CALL_1(sk->sk_prot->stream_memory_free,
1299 			        tcp_stream_memory_free,
1300 				sk, wake) : true;
1301 #else
1302 	return sk->sk_prot->stream_memory_free ?
1303 		sk->sk_prot->stream_memory_free(sk, wake) : true;
1304 #endif
1305 }
1306 
1307 static inline bool sk_stream_memory_free(const struct sock *sk)
1308 {
1309 	return __sk_stream_memory_free(sk, 0);
1310 }
1311 
1312 static inline bool __sk_stream_is_writeable(const struct sock *sk, int wake)
1313 {
1314 	return sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) &&
1315 	       __sk_stream_memory_free(sk, wake);
1316 }
1317 
1318 static inline bool sk_stream_is_writeable(const struct sock *sk)
1319 {
1320 	return __sk_stream_is_writeable(sk, 0);
1321 }
1322 
1323 static inline int sk_under_cgroup_hierarchy(struct sock *sk,
1324 					    struct cgroup *ancestor)
1325 {
1326 #ifdef CONFIG_SOCK_CGROUP_DATA
1327 	return cgroup_is_descendant(sock_cgroup_ptr(&sk->sk_cgrp_data),
1328 				    ancestor);
1329 #else
1330 	return -ENOTSUPP;
1331 #endif
1332 }
1333 
1334 static inline bool sk_has_memory_pressure(const struct sock *sk)
1335 {
1336 	return sk->sk_prot->memory_pressure != NULL;
1337 }
1338 
1339 static inline bool sk_under_memory_pressure(const struct sock *sk)
1340 {
1341 	if (!sk->sk_prot->memory_pressure)
1342 		return false;
1343 
1344 	if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
1345 	    mem_cgroup_under_socket_pressure(sk->sk_memcg))
1346 		return true;
1347 
1348 	return !!*sk->sk_prot->memory_pressure;
1349 }
1350 
1351 static inline long
1352 sk_memory_allocated(const struct sock *sk)
1353 {
1354 	return atomic_long_read(sk->sk_prot->memory_allocated);
1355 }
1356 
1357 static inline long
1358 sk_memory_allocated_add(struct sock *sk, int amt)
1359 {
1360 	return atomic_long_add_return(amt, sk->sk_prot->memory_allocated);
1361 }
1362 
1363 static inline void
1364 sk_memory_allocated_sub(struct sock *sk, int amt)
1365 {
1366 	atomic_long_sub(amt, sk->sk_prot->memory_allocated);
1367 }
1368 
1369 #define SK_ALLOC_PERCPU_COUNTER_BATCH 16
1370 
1371 static inline void sk_sockets_allocated_dec(struct sock *sk)
1372 {
1373 	percpu_counter_add_batch(sk->sk_prot->sockets_allocated, -1,
1374 				 SK_ALLOC_PERCPU_COUNTER_BATCH);
1375 }
1376 
1377 static inline void sk_sockets_allocated_inc(struct sock *sk)
1378 {
1379 	percpu_counter_add_batch(sk->sk_prot->sockets_allocated, 1,
1380 				 SK_ALLOC_PERCPU_COUNTER_BATCH);
1381 }
1382 
1383 static inline u64
1384 sk_sockets_allocated_read_positive(struct sock *sk)
1385 {
1386 	return percpu_counter_read_positive(sk->sk_prot->sockets_allocated);
1387 }
1388 
1389 static inline int
1390 proto_sockets_allocated_sum_positive(struct proto *prot)
1391 {
1392 	return percpu_counter_sum_positive(prot->sockets_allocated);
1393 }
1394 
1395 static inline long
1396 proto_memory_allocated(struct proto *prot)
1397 {
1398 	return atomic_long_read(prot->memory_allocated);
1399 }
1400 
1401 static inline bool
1402 proto_memory_pressure(struct proto *prot)
1403 {
1404 	if (!prot->memory_pressure)
1405 		return false;
1406 	return !!*prot->memory_pressure;
1407 }
1408 
1409 
1410 #ifdef CONFIG_PROC_FS
1411 /* Called with local bh disabled */
1412 void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
1413 int sock_prot_inuse_get(struct net *net, struct proto *proto);
1414 int sock_inuse_get(struct net *net);
1415 #else
1416 static inline void sock_prot_inuse_add(struct net *net, struct proto *prot,
1417 		int inc)
1418 {
1419 }
1420 #endif
1421 
1422 
1423 /* With per-bucket locks this operation is not-atomic, so that
1424  * this version is not worse.
1425  */
1426 static inline int __sk_prot_rehash(struct sock *sk)
1427 {
1428 	sk->sk_prot->unhash(sk);
1429 	return sk->sk_prot->hash(sk);
1430 }
1431 
1432 /* About 10 seconds */
1433 #define SOCK_DESTROY_TIME (10*HZ)
1434 
1435 /* Sockets 0-1023 can't be bound to unless you are superuser */
1436 #define PROT_SOCK	1024
1437 
1438 #define SHUTDOWN_MASK	3
1439 #define RCV_SHUTDOWN	1
1440 #define SEND_SHUTDOWN	2
1441 
1442 #define SOCK_BINDADDR_LOCK	4
1443 #define SOCK_BINDPORT_LOCK	8
1444 
1445 struct socket_alloc {
1446 	struct socket socket;
1447 	struct inode vfs_inode;
1448 };
1449 
1450 static inline struct socket *SOCKET_I(struct inode *inode)
1451 {
1452 	return &container_of(inode, struct socket_alloc, vfs_inode)->socket;
1453 }
1454 
1455 static inline struct inode *SOCK_INODE(struct socket *socket)
1456 {
1457 	return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
1458 }
1459 
1460 /*
1461  * Functions for memory accounting
1462  */
1463 int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind);
1464 int __sk_mem_schedule(struct sock *sk, int size, int kind);
1465 void __sk_mem_reduce_allocated(struct sock *sk, int amount);
1466 void __sk_mem_reclaim(struct sock *sk, int amount);
1467 
1468 /* We used to have PAGE_SIZE here, but systems with 64KB pages
1469  * do not necessarily have 16x time more memory than 4KB ones.
1470  */
1471 #define SK_MEM_QUANTUM 4096
1472 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
1473 #define SK_MEM_SEND	0
1474 #define SK_MEM_RECV	1
1475 
1476 /* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
1477 static inline long sk_prot_mem_limits(const struct sock *sk, int index)
1478 {
1479 	long val = sk->sk_prot->sysctl_mem[index];
1480 
1481 #if PAGE_SIZE > SK_MEM_QUANTUM
1482 	val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
1483 #elif PAGE_SIZE < SK_MEM_QUANTUM
1484 	val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
1485 #endif
1486 	return val;
1487 }
1488 
1489 static inline int sk_mem_pages(int amt)
1490 {
1491 	return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
1492 }
1493 
1494 static inline bool sk_has_account(struct sock *sk)
1495 {
1496 	/* return true if protocol supports memory accounting */
1497 	return !!sk->sk_prot->memory_allocated;
1498 }
1499 
1500 static inline bool sk_wmem_schedule(struct sock *sk, int size)
1501 {
1502 	if (!sk_has_account(sk))
1503 		return true;
1504 	return size <= sk->sk_forward_alloc ||
1505 		__sk_mem_schedule(sk, size, SK_MEM_SEND);
1506 }
1507 
1508 static inline bool
1509 sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
1510 {
1511 	if (!sk_has_account(sk))
1512 		return true;
1513 	return size <= sk->sk_forward_alloc ||
1514 		__sk_mem_schedule(sk, size, SK_MEM_RECV) ||
1515 		skb_pfmemalloc(skb);
1516 }
1517 
1518 static inline void sk_mem_reclaim(struct sock *sk)
1519 {
1520 	if (!sk_has_account(sk))
1521 		return;
1522 	if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
1523 		__sk_mem_reclaim(sk, sk->sk_forward_alloc);
1524 }
1525 
1526 static inline void sk_mem_reclaim_partial(struct sock *sk)
1527 {
1528 	if (!sk_has_account(sk))
1529 		return;
1530 	if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
1531 		__sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);
1532 }
1533 
1534 static inline void sk_mem_charge(struct sock *sk, int size)
1535 {
1536 	if (!sk_has_account(sk))
1537 		return;
1538 	sk->sk_forward_alloc -= size;
1539 }
1540 
1541 static inline void sk_mem_uncharge(struct sock *sk, int size)
1542 {
1543 	if (!sk_has_account(sk))
1544 		return;
1545 	sk->sk_forward_alloc += size;
1546 
1547 	/* Avoid a possible overflow.
1548 	 * TCP send queues can make this happen, if sk_mem_reclaim()
1549 	 * is not called and more than 2 GBytes are released at once.
1550 	 *
1551 	 * If we reach 2 MBytes, reclaim 1 MBytes right now, there is
1552 	 * no need to hold that much forward allocation anyway.
1553 	 */
1554 	if (unlikely(sk->sk_forward_alloc >= 1 << 21))
1555 		__sk_mem_reclaim(sk, 1 << 20);
1556 }
1557 
1558 DECLARE_STATIC_KEY_FALSE(tcp_tx_skb_cache_key);
1559 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
1560 {
1561 	sk_wmem_queued_add(sk, -skb->truesize);
1562 	sk_mem_uncharge(sk, skb->truesize);
1563 	if (static_branch_unlikely(&tcp_tx_skb_cache_key) &&
1564 	    !sk->sk_tx_skb_cache && !skb_cloned(skb)) {
1565 		skb_ext_reset(skb);
1566 		skb_zcopy_clear(skb, true);
1567 		sk->sk_tx_skb_cache = skb;
1568 		return;
1569 	}
1570 	__kfree_skb(skb);
1571 }
1572 
1573 static inline void sock_release_ownership(struct sock *sk)
1574 {
1575 	if (sk->sk_lock.owned) {
1576 		sk->sk_lock.owned = 0;
1577 
1578 		/* The sk_lock has mutex_unlock() semantics: */
1579 		mutex_release(&sk->sk_lock.dep_map, _RET_IP_);
1580 	}
1581 }
1582 
1583 /*
1584  * Macro so as to not evaluate some arguments when
1585  * lockdep is not enabled.
1586  *
1587  * Mark both the sk_lock and the sk_lock.slock as a
1588  * per-address-family lock class.
1589  */
1590 #define sock_lock_init_class_and_name(sk, sname, skey, name, key)	\
1591 do {									\
1592 	sk->sk_lock.owned = 0;						\
1593 	init_waitqueue_head(&sk->sk_lock.wq);				\
1594 	spin_lock_init(&(sk)->sk_lock.slock);				\
1595 	debug_check_no_locks_freed((void *)&(sk)->sk_lock,		\
1596 			sizeof((sk)->sk_lock));				\
1597 	lockdep_set_class_and_name(&(sk)->sk_lock.slock,		\
1598 				(skey), (sname));				\
1599 	lockdep_init_map(&(sk)->sk_lock.dep_map, (name), (key), 0);	\
1600 } while (0)
1601 
1602 static inline bool lockdep_sock_is_held(const struct sock *sk)
1603 {
1604 	return lockdep_is_held(&sk->sk_lock) ||
1605 	       lockdep_is_held(&sk->sk_lock.slock);
1606 }
1607 
1608 void lock_sock_nested(struct sock *sk, int subclass);
1609 
1610 static inline void lock_sock(struct sock *sk)
1611 {
1612 	lock_sock_nested(sk, 0);
1613 }
1614 
1615 void __lock_sock(struct sock *sk);
1616 void __release_sock(struct sock *sk);
1617 void release_sock(struct sock *sk);
1618 
1619 /* BH context may only use the following locking interface. */
1620 #define bh_lock_sock(__sk)	spin_lock(&((__sk)->sk_lock.slock))
1621 #define bh_lock_sock_nested(__sk) \
1622 				spin_lock_nested(&((__sk)->sk_lock.slock), \
1623 				SINGLE_DEPTH_NESTING)
1624 #define bh_unlock_sock(__sk)	spin_unlock(&((__sk)->sk_lock.slock))
1625 
1626 bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock);
1627 
1628 /**
1629  * unlock_sock_fast - complement of lock_sock_fast
1630  * @sk: socket
1631  * @slow: slow mode
1632  *
1633  * fast unlock socket for user context.
1634  * If slow mode is on, we call regular release_sock()
1635  */
1636 static inline void unlock_sock_fast(struct sock *sk, bool slow)
1637 	__releases(&sk->sk_lock.slock)
1638 {
1639 	if (slow) {
1640 		release_sock(sk);
1641 		__release(&sk->sk_lock.slock);
1642 	} else {
1643 		mutex_release(&sk->sk_lock.dep_map, _RET_IP_);
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 gfp_t gfp_memcg_charge(void)
2405 {
2406 	return in_softirq() ? GFP_NOWAIT : GFP_KERNEL;
2407 }
2408 
2409 static inline long sock_rcvtimeo(const struct sock *sk, bool noblock)
2410 {
2411 	return noblock ? 0 : sk->sk_rcvtimeo;
2412 }
2413 
2414 static inline long sock_sndtimeo(const struct sock *sk, bool noblock)
2415 {
2416 	return noblock ? 0 : sk->sk_sndtimeo;
2417 }
2418 
2419 static inline int sock_rcvlowat(const struct sock *sk, int waitall, int len)
2420 {
2421 	int v = waitall ? len : min_t(int, READ_ONCE(sk->sk_rcvlowat), len);
2422 
2423 	return v ?: 1;
2424 }
2425 
2426 /* Alas, with timeout socket operations are not restartable.
2427  * Compare this to poll().
2428  */
2429 static inline int sock_intr_errno(long timeo)
2430 {
2431 	return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
2432 }
2433 
2434 struct sock_skb_cb {
2435 	u32 dropcount;
2436 };
2437 
2438 /* Store sock_skb_cb at the end of skb->cb[] so protocol families
2439  * using skb->cb[] would keep using it directly and utilize its
2440  * alignement guarantee.
2441  */
2442 #define SOCK_SKB_CB_OFFSET ((sizeof_field(struct sk_buff, cb) - \
2443 			    sizeof(struct sock_skb_cb)))
2444 
2445 #define SOCK_SKB_CB(__skb) ((struct sock_skb_cb *)((__skb)->cb + \
2446 			    SOCK_SKB_CB_OFFSET))
2447 
2448 #define sock_skb_cb_check_size(size) \
2449 	BUILD_BUG_ON((size) > SOCK_SKB_CB_OFFSET)
2450 
2451 static inline void
2452 sock_skb_set_dropcount(const struct sock *sk, struct sk_buff *skb)
2453 {
2454 	SOCK_SKB_CB(skb)->dropcount = sock_flag(sk, SOCK_RXQ_OVFL) ?
2455 						atomic_read(&sk->sk_drops) : 0;
2456 }
2457 
2458 static inline void sk_drops_add(struct sock *sk, const struct sk_buff *skb)
2459 {
2460 	int segs = max_t(u16, 1, skb_shinfo(skb)->gso_segs);
2461 
2462 	atomic_add(segs, &sk->sk_drops);
2463 }
2464 
2465 static inline ktime_t sock_read_timestamp(struct sock *sk)
2466 {
2467 #if BITS_PER_LONG==32
2468 	unsigned int seq;
2469 	ktime_t kt;
2470 
2471 	do {
2472 		seq = read_seqbegin(&sk->sk_stamp_seq);
2473 		kt = sk->sk_stamp;
2474 	} while (read_seqretry(&sk->sk_stamp_seq, seq));
2475 
2476 	return kt;
2477 #else
2478 	return READ_ONCE(sk->sk_stamp);
2479 #endif
2480 }
2481 
2482 static inline void sock_write_timestamp(struct sock *sk, ktime_t kt)
2483 {
2484 #if BITS_PER_LONG==32
2485 	write_seqlock(&sk->sk_stamp_seq);
2486 	sk->sk_stamp = kt;
2487 	write_sequnlock(&sk->sk_stamp_seq);
2488 #else
2489 	WRITE_ONCE(sk->sk_stamp, kt);
2490 #endif
2491 }
2492 
2493 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
2494 			   struct sk_buff *skb);
2495 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
2496 			     struct sk_buff *skb);
2497 
2498 static inline void
2499 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
2500 {
2501 	ktime_t kt = skb->tstamp;
2502 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
2503 
2504 	/*
2505 	 * generate control messages if
2506 	 * - receive time stamping in software requested
2507 	 * - software time stamp available and wanted
2508 	 * - hardware time stamps available and wanted
2509 	 */
2510 	if (sock_flag(sk, SOCK_RCVTSTAMP) ||
2511 	    (sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
2512 	    (kt && sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
2513 	    (hwtstamps->hwtstamp &&
2514 	     (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
2515 		__sock_recv_timestamp(msg, sk, skb);
2516 	else
2517 		sock_write_timestamp(sk, kt);
2518 
2519 	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
2520 		__sock_recv_wifi_status(msg, sk, skb);
2521 }
2522 
2523 void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2524 			      struct sk_buff *skb);
2525 
2526 #define SK_DEFAULT_STAMP (-1L * NSEC_PER_SEC)
2527 static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
2528 					  struct sk_buff *skb)
2529 {
2530 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)			| \
2531 			   (1UL << SOCK_RCVTSTAMP))
2532 #define TSFLAGS_ANY	  (SOF_TIMESTAMPING_SOFTWARE			| \
2533 			   SOF_TIMESTAMPING_RAW_HARDWARE)
2534 
2535 	if (sk->sk_flags & FLAGS_TS_OR_DROPS || sk->sk_tsflags & TSFLAGS_ANY)
2536 		__sock_recv_ts_and_drops(msg, sk, skb);
2537 	else if (unlikely(sock_flag(sk, SOCK_TIMESTAMP)))
2538 		sock_write_timestamp(sk, skb->tstamp);
2539 	else if (unlikely(sk->sk_stamp == SK_DEFAULT_STAMP))
2540 		sock_write_timestamp(sk, 0);
2541 }
2542 
2543 void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags);
2544 
2545 /**
2546  * _sock_tx_timestamp - checks whether the outgoing packet is to be time stamped
2547  * @sk:		socket sending this packet
2548  * @tsflags:	timestamping flags to use
2549  * @tx_flags:	completed with instructions for time stamping
2550  * @tskey:      filled in with next sk_tskey (not for TCP, which uses seqno)
2551  *
2552  * Note: callers should take care of initial ``*tx_flags`` value (usually 0)
2553  */
2554 static inline void _sock_tx_timestamp(struct sock *sk, __u16 tsflags,
2555 				      __u8 *tx_flags, __u32 *tskey)
2556 {
2557 	if (unlikely(tsflags)) {
2558 		__sock_tx_timestamp(tsflags, tx_flags);
2559 		if (tsflags & SOF_TIMESTAMPING_OPT_ID && tskey &&
2560 		    tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
2561 			*tskey = sk->sk_tskey++;
2562 	}
2563 	if (unlikely(sock_flag(sk, SOCK_WIFI_STATUS)))
2564 		*tx_flags |= SKBTX_WIFI_STATUS;
2565 }
2566 
2567 static inline void sock_tx_timestamp(struct sock *sk, __u16 tsflags,
2568 				     __u8 *tx_flags)
2569 {
2570 	_sock_tx_timestamp(sk, tsflags, tx_flags, NULL);
2571 }
2572 
2573 static inline void skb_setup_tx_timestamp(struct sk_buff *skb, __u16 tsflags)
2574 {
2575 	_sock_tx_timestamp(skb->sk, tsflags, &skb_shinfo(skb)->tx_flags,
2576 			   &skb_shinfo(skb)->tskey);
2577 }
2578 
2579 DECLARE_STATIC_KEY_FALSE(tcp_rx_skb_cache_key);
2580 /**
2581  * sk_eat_skb - Release a skb if it is no longer needed
2582  * @sk: socket to eat this skb from
2583  * @skb: socket buffer to eat
2584  *
2585  * This routine must be called with interrupts disabled or with the socket
2586  * locked so that the sk_buff queue operation is ok.
2587 */
2588 static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb)
2589 {
2590 	__skb_unlink(skb, &sk->sk_receive_queue);
2591 	if (static_branch_unlikely(&tcp_rx_skb_cache_key) &&
2592 	    !sk->sk_rx_skb_cache) {
2593 		sk->sk_rx_skb_cache = skb;
2594 		skb_orphan(skb);
2595 		return;
2596 	}
2597 	__kfree_skb(skb);
2598 }
2599 
2600 static inline
2601 struct net *sock_net(const struct sock *sk)
2602 {
2603 	return read_pnet(&sk->sk_net);
2604 }
2605 
2606 static inline
2607 void sock_net_set(struct sock *sk, struct net *net)
2608 {
2609 	write_pnet(&sk->sk_net, net);
2610 }
2611 
2612 static inline bool
2613 skb_sk_is_prefetched(struct sk_buff *skb)
2614 {
2615 #ifdef CONFIG_INET
2616 	return skb->destructor == sock_pfree;
2617 #else
2618 	return false;
2619 #endif /* CONFIG_INET */
2620 }
2621 
2622 /* This helper checks if a socket is a full socket,
2623  * ie _not_ a timewait or request socket.
2624  */
2625 static inline bool sk_fullsock(const struct sock *sk)
2626 {
2627 	return (1 << sk->sk_state) & ~(TCPF_TIME_WAIT | TCPF_NEW_SYN_RECV);
2628 }
2629 
2630 static inline bool
2631 sk_is_refcounted(struct sock *sk)
2632 {
2633 	/* Only full sockets have sk->sk_flags. */
2634 	return !sk_fullsock(sk) || !sock_flag(sk, SOCK_RCU_FREE);
2635 }
2636 
2637 /**
2638  * skb_steal_sock - steal a socket from an sk_buff
2639  * @skb: sk_buff to steal the socket from
2640  * @refcounted: is set to true if the socket is reference-counted
2641  */
2642 static inline struct sock *
2643 skb_steal_sock(struct sk_buff *skb, bool *refcounted)
2644 {
2645 	if (skb->sk) {
2646 		struct sock *sk = skb->sk;
2647 
2648 		*refcounted = true;
2649 		if (skb_sk_is_prefetched(skb))
2650 			*refcounted = sk_is_refcounted(sk);
2651 		skb->destructor = NULL;
2652 		skb->sk = NULL;
2653 		return sk;
2654 	}
2655 	*refcounted = false;
2656 	return NULL;
2657 }
2658 
2659 /* Checks if this SKB belongs to an HW offloaded socket
2660  * and whether any SW fallbacks are required based on dev.
2661  * Check decrypted mark in case skb_orphan() cleared socket.
2662  */
2663 static inline struct sk_buff *sk_validate_xmit_skb(struct sk_buff *skb,
2664 						   struct net_device *dev)
2665 {
2666 #ifdef CONFIG_SOCK_VALIDATE_XMIT
2667 	struct sock *sk = skb->sk;
2668 
2669 	if (sk && sk_fullsock(sk) && sk->sk_validate_xmit_skb) {
2670 		skb = sk->sk_validate_xmit_skb(sk, dev, skb);
2671 #ifdef CONFIG_TLS_DEVICE
2672 	} else if (unlikely(skb->decrypted)) {
2673 		pr_warn_ratelimited("unencrypted skb with no associated socket - dropping\n");
2674 		kfree_skb(skb);
2675 		skb = NULL;
2676 #endif
2677 	}
2678 #endif
2679 
2680 	return skb;
2681 }
2682 
2683 /* This helper checks if a socket is a LISTEN or NEW_SYN_RECV
2684  * SYNACK messages can be attached to either ones (depending on SYNCOOKIE)
2685  */
2686 static inline bool sk_listener(const struct sock *sk)
2687 {
2688 	return (1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV);
2689 }
2690 
2691 void sock_enable_timestamp(struct sock *sk, enum sock_flags flag);
2692 int sock_recv_errqueue(struct sock *sk, struct msghdr *msg, int len, int level,
2693 		       int type);
2694 
2695 bool sk_ns_capable(const struct sock *sk,
2696 		   struct user_namespace *user_ns, int cap);
2697 bool sk_capable(const struct sock *sk, int cap);
2698 bool sk_net_capable(const struct sock *sk, int cap);
2699 
2700 void sk_get_meminfo(const struct sock *sk, u32 *meminfo);
2701 
2702 /* Take into consideration the size of the struct sk_buff overhead in the
2703  * determination of these values, since that is non-constant across
2704  * platforms.  This makes socket queueing behavior and performance
2705  * not depend upon such differences.
2706  */
2707 #define _SK_MEM_PACKETS		256
2708 #define _SK_MEM_OVERHEAD	SKB_TRUESIZE(256)
2709 #define SK_WMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2710 #define SK_RMEM_MAX		(_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
2711 
2712 extern __u32 sysctl_wmem_max;
2713 extern __u32 sysctl_rmem_max;
2714 
2715 extern int sysctl_tstamp_allow_data;
2716 extern int sysctl_optmem_max;
2717 
2718 extern __u32 sysctl_wmem_default;
2719 extern __u32 sysctl_rmem_default;
2720 
2721 #define SKB_FRAG_PAGE_ORDER	get_order(32768)
2722 DECLARE_STATIC_KEY_FALSE(net_high_order_alloc_disable_key);
2723 
2724 static inline int sk_get_wmem0(const struct sock *sk, const struct proto *proto)
2725 {
2726 	/* Does this proto have per netns sysctl_wmem ? */
2727 	if (proto->sysctl_wmem_offset)
2728 		return *(int *)((void *)sock_net(sk) + proto->sysctl_wmem_offset);
2729 
2730 	return *proto->sysctl_wmem;
2731 }
2732 
2733 static inline int sk_get_rmem0(const struct sock *sk, const struct proto *proto)
2734 {
2735 	/* Does this proto have per netns sysctl_rmem ? */
2736 	if (proto->sysctl_rmem_offset)
2737 		return *(int *)((void *)sock_net(sk) + proto->sysctl_rmem_offset);
2738 
2739 	return *proto->sysctl_rmem;
2740 }
2741 
2742 /* Default TCP Small queue budget is ~1 ms of data (1sec >> 10)
2743  * Some wifi drivers need to tweak it to get more chunks.
2744  * They can use this helper from their ndo_start_xmit()
2745  */
2746 static inline void sk_pacing_shift_update(struct sock *sk, int val)
2747 {
2748 	if (!sk || !sk_fullsock(sk) || READ_ONCE(sk->sk_pacing_shift) == val)
2749 		return;
2750 	WRITE_ONCE(sk->sk_pacing_shift, val);
2751 }
2752 
2753 /* if a socket is bound to a device, check that the given device
2754  * index is either the same or that the socket is bound to an L3
2755  * master device and the given device index is also enslaved to
2756  * that L3 master
2757  */
2758 static inline bool sk_dev_equal_l3scope(struct sock *sk, int dif)
2759 {
2760 	int mdif;
2761 
2762 	if (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif)
2763 		return true;
2764 
2765 	mdif = l3mdev_master_ifindex_by_index(sock_net(sk), dif);
2766 	if (mdif && mdif == sk->sk_bound_dev_if)
2767 		return true;
2768 
2769 	return false;
2770 }
2771 
2772 void sock_def_readable(struct sock *sk);
2773 
2774 int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk);
2775 void sock_set_timestamp(struct sock *sk, int optname, bool valbool);
2776 int sock_set_timestamping(struct sock *sk, int optname,
2777 			  struct so_timestamping timestamping);
2778 
2779 void sock_enable_timestamps(struct sock *sk);
2780 void sock_no_linger(struct sock *sk);
2781 void sock_set_keepalive(struct sock *sk);
2782 void sock_set_priority(struct sock *sk, u32 priority);
2783 void sock_set_rcvbuf(struct sock *sk, int val);
2784 void sock_set_mark(struct sock *sk, u32 val);
2785 void sock_set_reuseaddr(struct sock *sk);
2786 void sock_set_reuseport(struct sock *sk);
2787 void sock_set_sndtimeo(struct sock *sk, s64 secs);
2788 
2789 int sock_bind_add(struct sock *sk, struct sockaddr *addr, int addr_len);
2790 
2791 #endif	/* _SOCK_H */
2792