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/socket.h>
#include <asm/socket.h>

#define NPROTO		AF_MAX

#define SYS_SOCKET	1		/* sys_socket(2)		*/
#define SYS_BIND	2		/* sys_bind(2)			*/
#define SYS_CONNECT	3		/* sys_connect(2)		*/
#define SYS_LISTEN	4		/* sys_listen(2)		*/
#define SYS_ACCEPT	5		/* sys_accept(2)		*/
#define SYS_GETSOCKNAME	6		/* sys_getsockname(2)		*/
#define SYS_GETPEERNAME	7		/* sys_getpeername(2)		*/
#define SYS_SOCKETPAIR	8		/* sys_socketpair(2)		*/
#define SYS_SEND	9		/* sys_send(2)			*/
#define SYS_RECV	10		/* sys_recv(2)			*/
#define SYS_SENDTO	11		/* sys_sendto(2)		*/
#define SYS_RECVFROM	12		/* sys_recvfrom(2)		*/
#define SYS_SHUTDOWN	13		/* sys_shutdown(2)		*/
#define SYS_SETSOCKOPT	14		/* sys_setsockopt(2)		*/
#define SYS_GETSOCKOPT	15		/* sys_getsockopt(2)		*/
#define SYS_SENDMSG	16		/* sys_sendmsg(2)		*/
#define SYS_RECVMSG	17		/* sys_recvmsg(2)		*/
#define SYS_ACCEPT4	18		/* sys_accept4(2)		*/
#define SYS_RECVMMSG	19		/* sys_recvmmsg(2)		*/

typedef enum {
	SS_FREE = 0,			/* not allocated		*/
	SS_UNCONNECTED,			/* unconnected to any socket	*/
	SS_CONNECTING,			/* in process of connecting	*/
	SS_CONNECTED,			/* connected to socket		*/
	SS_DISCONNECTING		/* in process of disconnecting	*/
} socket_state;

#define __SO_ACCEPTCON	(1 << 16)	/* performed a listen		*/

#ifdef __KERNEL__
#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>

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

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

#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		= 0,
	SHUT_WR		= 1,
	SHUT_RDWR	= 2,
};

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);
	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);
};

#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,
};

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

#define net_random()		random32()
#define net_srandom(seed)	srandom32((__force u32)seed)

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

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

#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#include <linux/ratelimit.h>
extern struct ratelimit_state net_ratelimit_state;
#endif

#endif /* __KERNEL__ */
#endif	/* _LINUX_NET_H */