1. 根目录:
2. include
3. linux
4. net.h

/*
 * NET		An implementation of the SOCKET network access protocol.
 *		This is the master header file for the Linux NET layer,
 *		or, in plain English: the networking handling part of the
 *		kernel.
 *
 * Version:	@(#)net.h	1.0.3	05/25/93
 *
 * Authors:	Orest Zborowski, <obz@Kodak.COM>
 *		Ross Biro
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
#ifndef _LINUX_NET_H
#define _LINUX_NET_H

#include <linux/stringify.h>
#include <linux/random.h>
#include <linux/wait.h>
#include <linux/fcntl.h>	/* For O_CLOEXEC and O_NONBLOCK */
#include <linux/kmemcheck.h>
#include <linux/rcupdate.h>
#include <linux/jump_label.h>
#include <uapi/linux/net.h>

struct poll_table_struct;
struct pipe_inode_info;
struct inode;
struct file;
struct net;

#define SOCK_ASYNC_NOSPACE	0
#define SOCK_ASYNC_WAITDATA	1
#define SOCK_NOSPACE		2
#define SOCK_PASSCRED		3
#define SOCK_PASSSEC		4
#define SOCK_EXTERNALLY_ALLOCATED 5

#ifndef ARCH_HAS_SOCKET_TYPES
/**
 * enum sock_type - Socket types
 * @SOCK_STREAM: stream (connection) socket
 * @SOCK_DGRAM: datagram (conn.less) socket
 * @SOCK_RAW: raw socket
 * @SOCK_RDM: reliably-delivered message
 * @SOCK_SEQPACKET: sequential packet socket
 * @SOCK_DCCP: Datagram Congestion Control Protocol socket
 * @SOCK_PACKET: linux specific way of getting packets at the dev level.
 *		  For writing rarp and other similar things on the user level.
 *
 * When adding some new socket type please
 * grep ARCH_HAS_SOCKET_TYPE include/asm-* /socket.h, at least MIPS
 * overrides this enum for binary compat reasons.
 */
enum sock_type {
	SOCK_STREAM	= 1,
	SOCK_DGRAM	= 2,
	SOCK_RAW	= 3,
	SOCK_RDM	= 4,
	SOCK_SEQPACKET	= 5,
	SOCK_DCCP	= 6,
	SOCK_PACKET	= 10,
};

#define SOCK_MAX (SOCK_PACKET + 1)
/* Mask which covers at least up to SOCK_MASK-1.  The
 * remaining bits are used as flags. */
#define SOCK_TYPE_MASK 0xf

/* Flags for socket, socketpair, accept4 */
#define SOCK_CLOEXEC	O_CLOEXEC
#ifndef SOCK_NONBLOCK
#define SOCK_NONBLOCK	O_NONBLOCK
#endif

#endif /* ARCH_HAS_SOCKET_TYPES */

enum sock_shutdown_cmd {
	SHUT_RD,
	SHUT_WR,
	SHUT_RDWR,
};

struct socket_wq {
	/* Note: wait MUST be first field of socket_wq */
	wait_queue_head_t	wait;
	struct fasync_struct	*fasync_list;
	struct rcu_head		rcu;
} ____cacheline_aligned_in_smp;

/**
 *  struct socket - general BSD socket
 *  @state: socket state (%SS_CONNECTED, etc)
 *  @type: socket type (%SOCK_STREAM, etc)
 *  @flags: socket flags (%SOCK_ASYNC_NOSPACE, etc)
 *  @ops: protocol specific socket operations
 *  @file: File back pointer for gc
 *  @sk: internal networking protocol agnostic socket representation
 *  @wq: wait queue for several uses
 */
struct socket {
	socket_state		state;

	kmemcheck_bitfield_begin(type);
	short			type;
	kmemcheck_bitfield_end(type);

	unsigned long		flags;

	struct socket_wq __rcu	*wq;

	struct file		*file;
	struct sock		*sk;
	const struct proto_ops	*ops;
};

struct vm_area_struct;
struct page;
struct kiocb;
struct sockaddr;
struct msghdr;
struct module;

struct proto_ops {
	int		family;
	struct module	*owner;
	int		(*release)   (struct socket *sock);
	int		(*bind)	     (struct socket *sock,
				      struct sockaddr *myaddr,
				      int sockaddr_len);
	int		(*connect)   (struct socket *sock,
				      struct sockaddr *vaddr,
				      int sockaddr_len, int flags);
	int		(*socketpair)(struct socket *sock1,
				      struct socket *sock2);
	int		(*accept)    (struct socket *sock,
				      struct socket *newsock, int flags);
	int		(*getname)   (struct socket *sock,
				      struct sockaddr *addr,
				      int *sockaddr_len, int peer);
	unsigned int	(*poll)	     (struct file *file, struct socket *sock,
				      struct poll_table_struct *wait);
	int		(*ioctl)     (struct socket *sock, unsigned int cmd,
				      unsigned long arg);
#ifdef CONFIG_COMPAT
	int	 	(*compat_ioctl) (struct socket *sock, unsigned int cmd,
				      unsigned long arg);
#endif
	int		(*listen)    (struct socket *sock, int len);
	int		(*shutdown)  (struct socket *sock, int flags);
	int		(*setsockopt)(struct socket *sock, int level,
				      int optname, char __user *optval, unsigned int optlen);
	int		(*getsockopt)(struct socket *sock, int level,
				      int optname, char __user *optval, int __user *optlen);
#ifdef CONFIG_COMPAT
	int		(*compat_setsockopt)(struct socket *sock, int level,
				      int optname, char __user *optval, unsigned int optlen);
	int		(*compat_getsockopt)(struct socket *sock, int level,
				      int optname, char __user *optval, int __user *optlen);
#endif
	int		(*sendmsg)   (struct kiocb *iocb, struct socket *sock,
				      struct msghdr *m, size_t total_len);
	/* Notes for implementing recvmsg:
	 * ===============================
	 * msg->msg_namelen should get updated by the recvmsg handlers
	 * iff msg_name != NULL. It is by default 0 to prevent
	 * returning uninitialized memory to user space.  The recvfrom
	 * handlers can assume that msg.msg_name is either NULL or has
	 * a minimum size of sizeof(struct sockaddr_storage).
	 */
	int		(*recvmsg)   (struct kiocb *iocb, struct socket *sock,
				      struct msghdr *m, size_t total_len,
				      int flags);
	int		(*mmap)	     (struct file *file, struct socket *sock,
				      struct vm_area_struct * vma);
	ssize_t		(*sendpage)  (struct socket *sock, struct page *page,
				      int offset, size_t size, int flags);
	ssize_t 	(*splice_read)(struct socket *sock,  loff_t *ppos,
				       struct pipe_inode_info *pipe, size_t len, unsigned int flags);
	int		(*set_peek_off)(struct sock *sk, int val);
};

#define DECLARE_SOCKADDR(type, dst, src)	\
	type dst = ({ __sockaddr_check_size(sizeof(*dst)); (type) src; })

struct net_proto_family {
	int		family;
	int		(*create)(struct net *net, struct socket *sock,
				  int protocol, int kern);
	struct module	*owner;
};

struct iovec;
struct kvec;

enum {
	SOCK_WAKE_IO,
	SOCK_WAKE_WAITD,
	SOCK_WAKE_SPACE,
	SOCK_WAKE_URG,
};

int sock_wake_async(struct socket *sk, int how, int band);
int sock_register(const struct net_proto_family *fam);
void sock_unregister(int family);
int __sock_create(struct net *net, int family, int type, int proto,
		  struct socket **res, int kern);
int sock_create(int family, int type, int proto, struct socket **res);
int sock_create_kern(int family, int type, int proto, struct socket **res);
int sock_create_lite(int family, int type, int proto, struct socket **res);
void sock_release(struct socket *sock);
int sock_sendmsg(struct socket *sock, struct msghdr *msg, size_t len);
int sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
		 int flags);
struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname);
struct socket *sockfd_lookup(int fd, int *err);
struct socket *sock_from_file(struct file *file, int *err);
#define		     sockfd_put(sock) fput(sock->file)
int net_ratelimit(void);

#define net_ratelimited_function(function, ...)			\
do {								\
	if (net_ratelimit())					\
		function(__VA_ARGS__);				\
} while (0)

#define net_emerg_ratelimited(fmt, ...)				\
	net_ratelimited_function(pr_emerg, fmt, ##__VA_ARGS__)
#define net_alert_ratelimited(fmt, ...)				\
	net_ratelimited_function(pr_alert, fmt, ##__VA_ARGS__)
#define net_crit_ratelimited(fmt, ...)				\
	net_ratelimited_function(pr_crit, fmt, ##__VA_ARGS__)
#define net_err_ratelimited(fmt, ...)				\
	net_ratelimited_function(pr_err, fmt, ##__VA_ARGS__)
#define net_notice_ratelimited(fmt, ...)			\
	net_ratelimited_function(pr_notice, fmt, ##__VA_ARGS__)
#define net_warn_ratelimited(fmt, ...)				\
	net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
#define net_info_ratelimited(fmt, ...)				\
	net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
#define net_dbg_ratelimited(fmt, ...)				\
	net_ratelimited_function(pr_debug, fmt, ##__VA_ARGS__)

bool __net_get_random_once(void *buf, int nbytes, bool *done,
			   struct static_key *done_key);

#define net_get_random_once(buf, nbytes)				\
	({								\
		bool ___ret = false;					\
		static bool ___done = false;				\
		static struct static_key ___once_key =			\
			STATIC_KEY_INIT_TRUE;				\
		if (static_key_true(&___once_key))			\
			___ret = __net_get_random_once(buf,		\
						       nbytes,		\
						       &___done,	\
						       &___once_key);	\
		___ret;							\
	})

int kernel_sendmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
		   size_t num, size_t len);
int kernel_recvmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
		   size_t num, size_t len, int flags);

int kernel_bind(struct socket *sock, struct sockaddr *addr, int addrlen);
int kernel_listen(struct socket *sock, int backlog);
int kernel_accept(struct socket *sock, struct socket **newsock, int flags);
int kernel_connect(struct socket *sock, struct sockaddr *addr, int addrlen,
		   int flags);
int kernel_getsockname(struct socket *sock, struct sockaddr *addr,
		       int *addrlen);
int kernel_getpeername(struct socket *sock, struct sockaddr *addr,
		       int *addrlen);
int kernel_getsockopt(struct socket *sock, int level, int optname, char *optval,
		      int *optlen);
int kernel_setsockopt(struct socket *sock, int level, int optname, char *optval,
		      unsigned int optlen);
int kernel_sendpage(struct socket *sock, struct page *page, int offset,
		    size_t size, int flags);
int kernel_sock_ioctl(struct socket *sock, int cmd, unsigned long arg);
int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how);

#define MODULE_ALIAS_NETPROTO(proto) \
	MODULE_ALIAS("net-pf-" __stringify(proto))

#define MODULE_ALIAS_NET_PF_PROTO(pf, proto) \
	MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto))

#define MODULE_ALIAS_NET_PF_PROTO_TYPE(pf, proto, type) \
	MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto) \
		     "-type-" __stringify(type))

#define MODULE_ALIAS_NET_PF_PROTO_NAME(pf, proto, name) \
	MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto) \
		     name)
#endif	/* _LINUX_NET_H */