text: #ifndef _LINUX_SOCKET_H
  #define _LINUX_SOCKET_H
  
  /*
   * Desired design of maximum size and alignment (see RFC2553)
   */
  #define _K_SS_MAXSIZE	128	/* Implementation specific max size */
  #define _K_SS_ALIGNSIZE	(__alignof__ (struct sockaddr *))
  				/* Implementation specific desired alignment */
  
  struct __kernel_sockaddr_storage {
  	unsigned short	ss_family;		/* address family */
  	/* Following field(s) are implementation specific */
  	char		__data[_K_SS_MAXSIZE - sizeof(unsigned short)];
  				/* space to achieve desired size, */
  				/* _SS_MAXSIZE value minus size of ss_family */
  } __attribute__ ((aligned(_K_SS_ALIGNSIZE)));	/* force desired alignment */
  
  #ifdef __KERNEL__
  
  #include <asm/socket.h>			/* arch-dependent defines	*/
  #include <linux/sockios.h>		/* the SIOCxxx I/O controls	*/
  #include <linux/uio.h>			/* iovec support		*/
  #include <linux/types.h>		/* pid_t			*/
  #include <linux/compiler.h>		/* __user			*/
  
  #define __sockaddr_check_size(size)	\
  	BUILD_BUG_ON(((size) > sizeof(struct __kernel_sockaddr_storage)))
  
  #ifdef __KERNEL__
  # ifdef CONFIG_PROC_FS
  struct seq_file;
  extern void socket_seq_show(struct seq_file *seq);
  # endif
  #endif /* __KERNEL__ */
  
  typedef unsigned short	sa_family_t;
  
  /*
   *	1003.1g requires sa_family_t and that sa_data is char.
   */
   
  struct sockaddr {
  	sa_family_t	sa_family;	/* address family, AF_xxx	*/
  	char		sa_data[14];	/* 14 bytes of protocol address	*/
  };
  
  struct linger {
  	int		l_onoff;	/* Linger active		*/
  	int		l_linger;	/* How long to linger for	*/
  };
  
  #define sockaddr_storage __kernel_sockaddr_storage
  
  /*
   *	As we do 4.4BSD message passing we use a 4.4BSD message passing
   *	system, not 4.3. Thus msg_accrights(len) are now missing. They
   *	belong in an obscure libc emulation or the bin.
   */
   
  struct msghdr {
  	void	*	msg_name;	/* Socket name			*/
  	int		msg_namelen;	/* Length of name		*/
  	struct iovec *	msg_iov;	/* Data blocks			*/
  	__kernel_size_t	msg_iovlen;	/* Number of blocks		*/
  	void 	*	msg_control;	/* Per protocol magic (eg BSD file descriptor passing) */
  	__kernel_size_t	msg_controllen;	/* Length of cmsg list */
  	unsigned	msg_flags;
  };
  
  /* For recvmmsg/sendmmsg */
  struct mmsghdr {
  	struct msghdr   msg_hdr;
  	unsigned        msg_len;
  };
  
  /*
   *	POSIX 1003.1g - ancillary data object information
   *	Ancillary data consits of a sequence of pairs of
   *	(cmsghdr, cmsg_data[])
   */
  
  struct cmsghdr {
  	__kernel_size_t	cmsg_len;	/* data byte count, including hdr */
          int		cmsg_level;	/* originating protocol */
          int		cmsg_type;	/* protocol-specific type */
  };
  
  /*
   *	Ancilliary data object information MACROS
   *	Table 5-14 of POSIX 1003.1g
   */
  
  #define __CMSG_NXTHDR(ctl, len, cmsg) __cmsg_nxthdr((ctl),(len),(cmsg))
  #define CMSG_NXTHDR(mhdr, cmsg) cmsg_nxthdr((mhdr), (cmsg))
  
  #define CMSG_ALIGN(len) ( ((len)+sizeof(long)-1) & ~(sizeof(long)-1) )
  
  #define CMSG_DATA(cmsg)	((void *)((char *)(cmsg) + CMSG_ALIGN(sizeof(struct cmsghdr))))
  #define CMSG_SPACE(len) (CMSG_ALIGN(sizeof(struct cmsghdr)) + CMSG_ALIGN(len))
  #define CMSG_LEN(len) (CMSG_ALIGN(sizeof(struct cmsghdr)) + (len))
  
  #define __CMSG_FIRSTHDR(ctl,len) ((len) >= sizeof(struct cmsghdr) ? \
  				  (struct cmsghdr *)(ctl) : \
  				  (struct cmsghdr *)NULL)
  #define CMSG_FIRSTHDR(msg)	__CMSG_FIRSTHDR((msg)->msg_control, (msg)->msg_controllen)
  #define CMSG_OK(mhdr, cmsg) ((cmsg)->cmsg_len >= sizeof(struct cmsghdr) && \
  			     (cmsg)->cmsg_len <= (unsigned long) \
  			     ((mhdr)->msg_controllen - \
  			      ((char *)(cmsg) - (char *)(mhdr)->msg_control)))
  
  /*
   *	Get the next cmsg header
   *
   *	PLEASE, do not touch this function. If you think, that it is
   *	incorrect, grep kernel sources and think about consequences
   *	before trying to improve it.
   *
   *	Now it always returns valid, not truncated ancillary object
   *	HEADER. But caller still MUST check, that cmsg->cmsg_len is
   *	inside range, given by msg->msg_controllen before using
   *	ancillary object DATA.				--ANK (980731)
   */
   
  static inline struct cmsghdr * __cmsg_nxthdr(void *__ctl, __kernel_size_t __size,
  					       struct cmsghdr *__cmsg)
  {
  	struct cmsghdr * __ptr;
  
  	__ptr = (struct cmsghdr*)(((unsigned char *) __cmsg) +  CMSG_ALIGN(__cmsg->cmsg_len));
  	if ((unsigned long)((char*)(__ptr+1) - (char *) __ctl) > __size)
  		return (struct cmsghdr *)0;
  
  	return __ptr;
  }
  
  static inline struct cmsghdr * cmsg_nxthdr (struct msghdr *__msg, struct cmsghdr *__cmsg)
  {
  	return __cmsg_nxthdr(__msg->msg_control, __msg->msg_controllen, __cmsg);
  }
  
  /* "Socket"-level control message types: */
  
  #define	SCM_RIGHTS	0x01		/* rw: access rights (array of int) */
  #define SCM_CREDENTIALS 0x02		/* rw: struct ucred		*/
  #define SCM_SECURITY	0x03		/* rw: security label		*/
  
  struct ucred {
  	__u32	pid;
  	__u32	uid;
  	__u32	gid;
  };
  
  /* Supported address families. */
  #define AF_UNSPEC	0
  #define AF_UNIX		1	/* Unix domain sockets 		*/
  #define AF_LOCAL	1	/* POSIX name for AF_UNIX	*/
  #define AF_INET		2	/* Internet IP Protocol 	*/
  #define AF_AX25		3	/* Amateur Radio AX.25 		*/
  #define AF_IPX		4	/* Novell IPX 			*/
  #define AF_APPLETALK	5	/* AppleTalk DDP 		*/
  #define AF_NETROM	6	/* Amateur Radio NET/ROM 	*/
  #define AF_BRIDGE	7	/* Multiprotocol bridge 	*/
  #define AF_ATMPVC	8	/* ATM PVCs			*/
  #define AF_X25		9	/* Reserved for X.25 project 	*/
  #define AF_INET6	10	/* IP version 6			*/
  #define AF_ROSE		11	/* Amateur Radio X.25 PLP	*/
  #define AF_DECnet	12	/* Reserved for DECnet project	*/
  #define AF_NETBEUI	13	/* Reserved for 802.2LLC project*/
  #define AF_SECURITY	14	/* Security callback pseudo AF */
  #define AF_KEY		15      /* PF_KEY key management API */
  #define AF_NETLINK	16
  #define AF_ROUTE	AF_NETLINK /* Alias to emulate 4.4BSD */
  #define AF_PACKET	17	/* Packet family		*/
  #define AF_ASH		18	/* Ash				*/
  #define AF_ECONET	19	/* Acorn Econet			*/
  #define AF_ATMSVC	20	/* ATM SVCs			*/
  #define AF_RDS		21	/* RDS sockets 			*/
  #define AF_SNA		22	/* Linux SNA Project (nutters!) */
  #define AF_IRDA		23	/* IRDA sockets			*/
  #define AF_PPPOX	24	/* PPPoX sockets		*/
  #define AF_WANPIPE	25	/* Wanpipe API Sockets */
  #define AF_LLC		26	/* Linux LLC			*/
  #define AF_CAN		29	/* Controller Area Network      */
  #define AF_TIPC		30	/* TIPC sockets			*/
  #define AF_BLUETOOTH	31	/* Bluetooth sockets 		*/
  #define AF_IUCV		32	/* IUCV sockets			*/
  #define AF_RXRPC	33	/* RxRPC sockets 		*/
  #define AF_ISDN		34	/* mISDN sockets 		*/
  #define AF_PHONET	35	/* Phonet sockets		*/
  #define AF_IEEE802154	36	/* IEEE802154 sockets		*/
  #define AF_MAX		37	/* For now.. */
  
  /* Protocol families, same as address families. */
  #define PF_UNSPEC	AF_UNSPEC
  #define PF_UNIX		AF_UNIX
  #define PF_LOCAL	AF_LOCAL
  #define PF_INET		AF_INET
  #define PF_AX25		AF_AX25
  #define PF_IPX		AF_IPX
  #define PF_APPLETALK	AF_APPLETALK
  #define	PF_NETROM	AF_NETROM
  #define PF_BRIDGE	AF_BRIDGE
  #define PF_ATMPVC	AF_ATMPVC
  #define PF_X25		AF_X25
  #define PF_INET6	AF_INET6
  #define PF_ROSE		AF_ROSE
  #define PF_DECnet	AF_DECnet
  #define PF_NETBEUI	AF_NETBEUI
  #define PF_SECURITY	AF_SECURITY
  #define PF_KEY		AF_KEY
  #define PF_NETLINK	AF_NETLINK
  #define PF_ROUTE	AF_ROUTE
  #define PF_PACKET	AF_PACKET
  #define PF_ASH		AF_ASH
  #define PF_ECONET	AF_ECONET
  #define PF_ATMSVC	AF_ATMSVC
  #define PF_RDS		AF_RDS
  #define PF_SNA		AF_SNA
  #define PF_IRDA		AF_IRDA
  #define PF_PPPOX	AF_PPPOX
  #define PF_WANPIPE	AF_WANPIPE
  #define PF_LLC		AF_LLC
  #define PF_CAN		AF_CAN
  #define PF_TIPC		AF_TIPC
  #define PF_BLUETOOTH	AF_BLUETOOTH
  #define PF_IUCV		AF_IUCV
  #define PF_RXRPC	AF_RXRPC
  #define PF_ISDN		AF_ISDN
  #define PF_PHONET	AF_PHONET
  #define PF_IEEE802154	AF_IEEE802154
  #define PF_MAX		AF_MAX
  
  /* Maximum queue length specifiable by listen.  */
  #define SOMAXCONN	128
  
  /* Flags we can use with send/ and recv. 
     Added those for 1003.1g not all are supported yet
   */
   
  #define MSG_OOB		1
  #define MSG_PEEK	2
  #define MSG_DONTROUTE	4
  #define MSG_TRYHARD     4       /* Synonym for MSG_DONTROUTE for DECnet */
  #define MSG_CTRUNC	8
  #define MSG_PROBE	0x10	/* Do not send. Only probe path f.e. for MTU */
  #define MSG_TRUNC	0x20
  #define MSG_DONTWAIT	0x40	/* Nonblocking io		 */
  #define MSG_EOR         0x80	/* End of record */
  #define MSG_WAITALL	0x100	/* Wait for a full request */
  #define MSG_FIN         0x200
  #define MSG_SYN		0x400
  #define MSG_CONFIRM	0x800	/* Confirm path validity */
  #define MSG_RST		0x1000
  #define MSG_ERRQUEUE	0x2000	/* Fetch message from error queue */
  #define MSG_NOSIGNAL	0x4000	/* Do not generate SIGPIPE */
  #define MSG_MORE	0x8000	/* Sender will send more */
  #define MSG_WAITFORONE	0x10000	/* recvmmsg(): block until 1+ packets avail */
  
  #define MSG_EOF         MSG_FIN
  
  #define MSG_CMSG_CLOEXEC 0x40000000	/* Set close_on_exit for file
  					   descriptor received through
  					   SCM_RIGHTS */
  #if defined(CONFIG_COMPAT)
  #define MSG_CMSG_COMPAT	0x80000000	/* This message needs 32 bit fixups */
  #else
  #define MSG_CMSG_COMPAT	0		/* We never have 32 bit fixups */
  #endif
  
  
  /* Setsockoptions(2) level. Thanks to BSD these must match IPPROTO_xxx */
  #define SOL_IP		0
  /* #define SOL_ICMP	1	No-no-no! Due to Linux :-) we cannot use SOL_ICMP=1 */
  #define SOL_TCP		6
  #define SOL_UDP		17
  #define SOL_IPV6	41
  #define SOL_ICMPV6	58
  #define SOL_SCTP	132
  #define SOL_UDPLITE	136     /* UDP-Lite (RFC 3828) */
  #define SOL_RAW		255
  #define SOL_IPX		256
  #define SOL_AX25	257
  #define SOL_ATALK	258
  #define SOL_NETROM	259
  #define SOL_ROSE	260
  #define SOL_DECNET	261
  #define	SOL_X25		262
  #define SOL_PACKET	263
  #define SOL_ATM		264	/* ATM layer (cell level) */
  #define SOL_AAL		265	/* ATM Adaption Layer (packet level) */
  #define SOL_IRDA        266
  #define SOL_NETBEUI	267
  #define SOL_LLC		268
  #define SOL_DCCP	269
  #define SOL_NETLINK	270
  #define SOL_TIPC	271
  #define SOL_RXRPC	272
  #define SOL_PPPOL2TP	273
  #define SOL_BLUETOOTH	274
  #define SOL_PNPIPE	275
  #define SOL_RDS		276
  #define SOL_IUCV	277
  
  /* IPX options */
  #define IPX_TYPE	1
  
  #ifdef __KERNEL__
  extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
  extern int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
  			       int offset, int len);
  extern int csum_partial_copy_fromiovecend(unsigned char *kdata, 
  					  struct iovec *iov, 
  					  int offset, 
  					  unsigned int len, __wsum *csump);
  
  extern int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode);
  extern int memcpy_toiovec(struct iovec *v, unsigned char *kdata, int len);
  extern int memcpy_toiovecend(const struct iovec *v, unsigned char *kdata,
  			     int offset, int len);
  extern int move_addr_to_user(struct sockaddr *kaddr, int klen, void __user *uaddr, int __user *ulen);
  extern int move_addr_to_kernel(void __user *uaddr, int ulen, struct sockaddr *kaddr);
  extern int put_cmsg(struct msghdr*, int level, int type, int len, void *data);
  
  struct timespec;
  
  extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
  			  unsigned int flags, struct timespec *timeout);
  #endif
  #endif /* not kernel and not glibc */
  #endif /* _LINUX_SOCKET_H */
  