/**
 * D header file for POSIX.
 *
 * Copyright: Copyright Sean Kelly 2005 - 2009.
 * License:   $(HTTP www.boost.org/LICENSE_1_0.txt, Boost License 1.0).
 * Authors:   Sean Kelly, Alex Rønne Petersen
 * Standards: The Open Group Base Specifications Issue 6, IEEE Std 1003.1, 2004 Edition
 */

/*          Copyright Sean Kelly 2005 - 2009.
 * Distributed under the Boost Software License, Version 1.0.
 *    (See accompanying file LICENSE or copy at
 *          http://www.boost.org/LICENSE_1_0.txt)
 */
module core.sys.posix.sys.socket;

private import core.sys.posix.config;
public import core.sys.posix.sys.types; // for ssize_t
public import core.sys.posix.sys.uio;   // for iovec

version (OSX)
    version = Darwin;
else version (iOS)
    version = Darwin;
else version (TVOS)
    version = Darwin;
else version (WatchOS)
    version = Darwin;

version (ARM)     version = ARM_Any;
version (AArch64) version = ARM_Any;
version (HPPA)    version = HPPA_Any;
version (MIPS32)  version = MIPS_Any;
version (MIPS64)  version = MIPS_Any;
version (PPC)     version = PPC_Any;
version (PPC64)   version = PPC_Any;
version (RISCV32) version = RISCV_Any;
version (RISCV64) version = RISCV_Any;
version (S390)    version = IBMZ_Any;
version (SPARC)   version = SPARC_Any;
version (SPARC64) version = SPARC_Any;
version (SystemZ) version = IBMZ_Any;
version (X86)     version = X86_Any;
version (X86_64)  version = X86_Any;

version (Posix):
extern (C) nothrow @nogc:
@system:

//
// Required
//
/*
socklen_t
sa_family_t

struct sockaddr
{
    sa_family_t sa_family;
    char        sa_data[];
}

struct sockaddr_storage
{
    sa_family_t ss_family;
}

struct msghdr
{
    void*         msg_name;
    socklen_t     msg_namelen;
    struct iovec* msg_iov;
    int           msg_iovlen;
    void*         msg_control;
    socklen_t     msg_controllen;
    int           msg_flags;
}

struct iovec {} // from core.sys.posix.sys.uio

struct cmsghdr
{
    socklen_t cmsg_len;
    int       cmsg_level;
    int       cmsg_type;
}

SCM_RIGHTS

CMSG_DATA(cmsg)
CMSG_NXTHDR(mhdr,cmsg)
CMSG_FIRSTHDR(mhdr)

struct linger
{
    int l_onoff;
    int l_linger;
}

SOCK_DGRAM
SOCK_SEQPACKET
SOCK_STREAM

SOL_SOCKET

SO_ACCEPTCONN
SO_BROADCAST
SO_DEBUG
SO_DONTROUTE
SO_ERROR
SO_KEEPALIVE
SO_LINGER
SO_OOBINLINE
SO_RCVBUF
SO_RCVLOWAT
SO_RCVTIMEO
SO_REUSEADDR
SO_SNDBUF
SO_SNDLOWAT
SO_SNDTIMEO
SO_TYPE

SOMAXCONN

MSG_CTRUNC
MSG_DONTROUTE
MSG_EOR
MSG_OOB
MSG_PEEK
MSG_TRUNC
MSG_WAITALL

AF_INET
AF_UNIX
AF_UNSPEC

SHUT_RD
SHUT_RDWR
SHUT_WR

int     accept(int, sockaddr*, socklen_t*);
int     bind(int, const scope sockaddr*, socklen_t);
int     connect(int, const scope sockaddr*, socklen_t);
int     getpeername(int, sockaddr*, socklen_t*);
int     getsockname(int, sockaddr*, socklen_t*);
int     getsockopt(int, int, int, void*, socklen_t*);
int     listen(int, int);
ssize_t recv(int, void*, size_t, int);
ssize_t recvfrom(int, void*, size_t, int, sockaddr*, socklen_t*);
ssize_t recvmsg(int, msghdr*, int);
ssize_t send(int, const scope void*, size_t, int);
ssize_t sendmsg(int, const scope msghdr*, int);
ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
int     setsockopt(int, int, int, const scope void*, socklen_t);
int     shutdown(int, int);
int     socket(int, int, int);
int     sockatmark(int);
int     socketpair(int, int, int, ref int[2]);
*/

version (CRuntime_Glibc)
{
    // Some of the constants below and from the Bionic section are really from
    // the linux kernel headers.
    alias uint   socklen_t;
    alias ushort sa_family_t;

    struct sockaddr
    {
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    private enum : size_t
    {
        _SS_SIZE    = 128,
        _SS_PADSIZE = _SS_SIZE - (c_ulong.sizeof * 2)
    }

    struct sockaddr_storage
    {
        sa_family_t ss_family;
        c_ulong     __ss_align;
        byte[_SS_PADSIZE] __ss_padding;
    }

    struct msghdr
    {
        void*     msg_name;
        socklen_t msg_namelen;
        iovec*    msg_iov;
        size_t    msg_iovlen;
        void*     msg_control;
        size_t    msg_controllen;
        int       msg_flags;
    }

    struct cmsghdr
    {
        size_t cmsg_len;
        int    cmsg_level;
        int    cmsg_type;
        static if ( false /* (!is( __STRICT_ANSI__ ) && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L */ )
        {
            ubyte[1] __cmsg_data;
        }
    }

    enum : uint
    {
        SCM_RIGHTS = 0x01
    }

    static if ( false /* (!is( __STRICT_ANSI__ ) && __GNUC__ >= 2) || __STDC_VERSION__ >= 199901L */ )
    {
        extern (D) ubyte[1] CMSG_DATA( cmsghdr* cmsg ) pure nothrow @nogc { return cmsg.__cmsg_data; }
    }
    else
    {
        extern (D) inout(ubyte)*   CMSG_DATA( return inout(cmsghdr)* cmsg ) pure nothrow @nogc { return cast(ubyte*)( cmsg + 1 ); }
    }

    private inout(cmsghdr)* __cmsg_nxthdr(inout(msghdr)*, inout(cmsghdr)*) pure nothrow @nogc;
    extern (D)  inout(cmsghdr)* CMSG_NXTHDR(inout(msghdr)* msg, inout(cmsghdr)* cmsg) pure nothrow @nogc
    {
        return __cmsg_nxthdr(msg, cmsg);
    }

    extern (D) inout(cmsghdr)* CMSG_FIRSTHDR( inout(msghdr)* mhdr ) pure nothrow @nogc
    {
        return ( cast(size_t)mhdr.msg_controllen >= cmsghdr.sizeof
                             ? cast(inout(cmsghdr)*) mhdr.msg_control
                             : cast(inout(cmsghdr)*) null );
    }

    extern (D)
    {
        size_t CMSG_ALIGN( size_t len ) pure nothrow @nogc
        {
            return (len + size_t.sizeof - 1) & cast(size_t) (~(size_t.sizeof - 1));
        }

        size_t CMSG_LEN( size_t len ) pure nothrow @nogc
        {
            return CMSG_ALIGN(cmsghdr.sizeof) + len;
        }
    }

    extern (D) size_t CMSG_SPACE(size_t len) pure nothrow @nogc
    {
        return CMSG_ALIGN(len) + CMSG_ALIGN(cmsghdr.sizeof);
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    version (X86_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1
        }

        enum
        {
            SOL_SOCKET      = 1
        }

        enum
        {
            SO_ACCEPTCONN   = 30,
            SO_BROADCAST    = 6,
            SO_DEBUG        = 1,
            SO_DONTROUTE    = 5,
            SO_ERROR        = 4,
            SO_KEEPALIVE    = 9,
            SO_LINGER       = 13,
            SO_OOBINLINE    = 10,
            SO_RCVBUF       = 8,
            SO_RCVLOWAT     = 18,
            SO_RCVTIMEO     = 20,
            SO_REUSEADDR    = 2,
            SO_REUSEPORT    = 15,
            SO_SNDBUF       = 7,
            SO_SNDLOWAT     = 19,
            SO_SNDTIMEO     = 21,
            SO_TYPE         = 3
        }
    }
    else version (HPPA_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1,
        }

        enum
        {
            SOL_SOCKET      = 0xffff
        }

        enum
        {
            SO_ACCEPTCONN   = 0x401c,
            SO_BROADCAST    = 0x0020,
            SO_DEBUG        = 0x0001,
            SO_DONTROUTE    = 0x0010,
            SO_ERROR        = 0x1007,
            SO_KEEPALIVE    = 0x0008,
            SO_LINGER       = 0x0080,
            SO_OOBINLINE    = 0x0100,
            SO_RCVBUF       = 0x1002,
            SO_RCVLOWAT     = 0x1004,
            SO_RCVTIMEO     = 0x1006,
            SO_REUSEADDR    = 0x0004,
            SO_SNDBUF       = 0x1001,
            SO_SNDLOWAT     = 0x1003,
            SO_SNDTIMEO     = 0x1005,
            SO_TYPE         = 0x1008,
        }
    }
    else version (MIPS_Any)
    {
        enum
        {
            SOCK_DGRAM      = 1,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 2,
        }

        enum
        {
            SOL_SOCKET      = 0xffff
        }

        enum
        {
            SO_ACCEPTCONN   = 0x1009,
            SO_BROADCAST    = 0x0020,
            SO_DEBUG        = 0x0001,
            SO_DONTROUTE    = 0x0010,
            SO_ERROR        = 0x1007,
            SO_KEEPALIVE    = 0x0008,
            SO_LINGER       = 0x0080,
            SO_OOBINLINE    = 0x0100,
            SO_RCVBUF       = 0x1002,
            SO_RCVLOWAT     = 0x1004,
            SO_RCVTIMEO     = 0x1006,
            SO_REUSEADDR    = 0x0004,
            SO_SNDBUF       = 0x1001,
            SO_SNDLOWAT     = 0x1003,
            SO_SNDTIMEO     = 0x1005,
            SO_TYPE         = 0x1008,
        }
    }
    else version (PPC_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1
        }

        enum
        {
            SOL_SOCKET      = 1
        }

        enum
        {
            SO_ACCEPTCONN   = 30,
            SO_BROADCAST    = 6,
            SO_DEBUG        = 1,
            SO_DONTROUTE    = 5,
            SO_ERROR        = 4,
            SO_KEEPALIVE    = 9,
            SO_LINGER       = 13,
            SO_OOBINLINE    = 10,
            SO_RCVBUF       = 8,
            SO_RCVLOWAT     = 16,
            SO_RCVTIMEO     = 18,
            SO_REUSEADDR    = 2,
            SO_SNDBUF       = 7,
            SO_SNDLOWAT     = 17,
            SO_SNDTIMEO     = 19,
            SO_TYPE         = 3
        }
    }
    else version (ARM_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1
        }

        enum
        {
            SOL_SOCKET      = 1
        }

        enum
        {
            SO_ACCEPTCONN   = 30,
            SO_BROADCAST    = 6,
            SO_DEBUG        = 1,
            SO_DONTROUTE    = 5,
            SO_ERROR        = 4,
            SO_KEEPALIVE    = 9,
            SO_LINGER       = 13,
            SO_OOBINLINE    = 10,
            SO_RCVBUF       = 8,
            SO_RCVLOWAT     = 18,
            SO_RCVTIMEO     = 20,
            SO_REUSEADDR    = 2,
            SO_REUSEPORT    = 15,
            SO_SNDBUF       = 7,
            SO_SNDLOWAT     = 19,
            SO_SNDTIMEO     = 21,
            SO_TYPE         = 3
        }
    }
    else version (RISCV_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1
        }

        enum
        {
            SOL_SOCKET      = 1
        }

        enum
        {
            SO_ACCEPTCONN   = 30,
            SO_BROADCAST    = 6,
            SO_DEBUG        = 1,
            SO_DONTROUTE    = 5,
            SO_ERROR        = 4,
            SO_KEEPALIVE    = 9,
            SO_LINGER       = 13,
            SO_OOBINLINE    = 10,
            SO_RCVBUF       = 8,
            SO_RCVLOWAT     = 18,
            SO_RCVTIMEO     = 20,
            SO_REUSEADDR    = 2,
            SO_SNDBUF       = 7,
            SO_SNDLOWAT     = 19,
            SO_SNDTIMEO     = 21,
            SO_TYPE         = 3
        }
    }
    else version (SPARC_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1
        }

        enum
        {
            SOL_SOCKET      = 1
        }

        enum
        {
            SO_ACCEPTCONN   = 30,
            SO_BROADCAST    = 6,
            SO_DEBUG        = 1,
            SO_DONTROUTE    = 5,
            SO_ERROR        = 4,
            SO_KEEPALIVE    = 9,
            SO_LINGER       = 13,
            SO_OOBINLINE    = 10,
            SO_RCVBUF       = 8,
            SO_RCVLOWAT     = 18,
            SO_RCVTIMEO     = 20,
            SO_REUSEADDR    = 2,
            SO_SNDBUF       = 7,
            SO_SNDLOWAT     = 19,
            SO_SNDTIMEO     = 21,
            SO_TYPE         = 3
        }
    }
    else version (IBMZ_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1
        }

        enum
        {
            SOL_SOCKET      = 1
        }

        enum
        {
            SO_ACCEPTCONN   = 30,
            SO_BROADCAST    = 6,
            SO_DEBUG        = 1,
            SO_DONTROUTE    = 5,
            SO_ERROR        = 4,
            SO_KEEPALIVE    = 9,
            SO_LINGER       = 13,
            SO_OOBINLINE    = 10,
            SO_RCVBUF       = 8,
            SO_RCVLOWAT     = 18,
            SO_RCVTIMEO     = 20,
            SO_REUSEADDR    = 2,
            SO_SNDBUF       = 7,
            SO_SNDLOWAT     = 19,
            SO_SNDTIMEO     = 21,
            SO_TYPE         = 3
        }
    }
    else
        static assert(0, "unimplemented");

    enum
    {
        SOMAXCONN       = 128
    }

    enum : uint
    {
        MSG_CTRUNC      = 0x08,
        MSG_DONTROUTE   = 0x04,
        MSG_EOR         = 0x80,
        MSG_OOB         = 0x01,
        MSG_PEEK        = 0x02,
        MSG_TRUNC       = 0x20,
        MSG_WAITALL     = 0x100,
        MSG_NOSIGNAL    = 0x4000
    }

    enum
    {
        AF_APPLETALK    = 5,
        AF_INET         = 2,
        AF_IPX          = 4,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0,
        PF_APPLETALK    = AF_APPLETALK,
        PF_IPX          = AF_IPX
    }

    enum int SOCK_RDM   = 4;

    enum
    {
        SHUT_RD,
        SHUT_WR,
        SHUT_RDWR
    }

    int     accept(int, scope sockaddr*, scope socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, scope sockaddr*, scope socklen_t*);
    int     getsockname(int, scope sockaddr*, scope socklen_t*);
    int     getsockopt(int, int, int, scope void*, scope socklen_t*);
    int     listen(int, int) @safe;
    ssize_t recv(int, scope void*, size_t, int);
    ssize_t recvfrom(int, scope void*, size_t, int, scope sockaddr*, scope socklen_t*);
    ssize_t recvmsg(int, scope msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int) @safe;
    int     socket(int, int, int) @safe;
    int     sockatmark(int) @safe;
    int     socketpair(int, int, int, ref int[2]) @safe;
}
else version (Darwin)
{
    alias uint   socklen_t;
    alias ubyte  sa_family_t;

    struct sockaddr
    {
        ubyte       sa_len;
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    private enum : size_t
    {
        _SS_PAD1    = long.sizeof - ubyte.sizeof - sa_family_t.sizeof,
        _SS_PAD2    = 128 - ubyte.sizeof - sa_family_t.sizeof - _SS_PAD1 - long.sizeof
    }

    struct sockaddr_storage
    {
         ubyte          ss_len;
         sa_family_t    ss_family;
         byte[_SS_PAD1] __ss_pad1;
         long           __ss_align;
         byte[_SS_PAD2] __ss_pad2;
    }

    struct msghdr
    {
        void*     msg_name;
        socklen_t msg_namelen;
        iovec*    msg_iov;
        int       msg_iovlen;
        void*     msg_control;
        socklen_t msg_controllen;
        int       msg_flags;
    }

    struct cmsghdr
    {
         socklen_t cmsg_len;
         int       cmsg_level;
         int       cmsg_type;
    }

    enum : uint
    {
        SCM_RIGHTS = 0x01
    }

    /+
    CMSG_DATA(cmsg)     ((unsigned char *)(cmsg) + \
                         ALIGN(sizeof(struct cmsghdr)))
    CMSG_NXTHDR(mhdr, cmsg) \
                        (((unsigned char *)(cmsg) + ALIGN((cmsg)->cmsg_len) + \
                         ALIGN(sizeof(struct cmsghdr)) > \
                         (unsigned char *)(mhdr)->msg_control +(mhdr)->msg_controllen) ? \
                         (struct cmsghdr *)0 /* NULL */ : \
                         (struct cmsghdr *)((unsigned char *)(cmsg) + ALIGN((cmsg)->cmsg_len)))
    CMSG_FIRSTHDR(mhdr) ((struct cmsghdr *)(mhdr)->msg_control)
    +/

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    enum
    {
        SOCK_DGRAM      = 2,
        SOCK_RDM        = 4,
        SOCK_SEQPACKET  = 5,
        SOCK_STREAM     = 1
    }

    enum : uint
    {
        SOL_SOCKET      = 0xffff
    }

    enum : uint
    {
        SO_ACCEPTCONN   = 0x0002,
        SO_BROADCAST    = 0x0020,
        SO_DEBUG        = 0x0001,
        SO_DONTROUTE    = 0x0010,
        SO_ERROR        = 0x1007,
        SO_KEEPALIVE    = 0x0008,
        SO_LINGER       = 0x1080,
        SO_NOSIGPIPE    = 0x1022, // non-standard
        SO_OOBINLINE    = 0x0100,
        SO_RCVBUF       = 0x1002,
        SO_RCVLOWAT     = 0x1004,
        SO_RCVTIMEO     = 0x1006,
        SO_REUSEADDR    = 0x0004,
        SO_REUSEPORT    = 0x0200,
        SO_SNDBUF       = 0x1001,
        SO_SNDLOWAT     = 0x1003,
        SO_SNDTIMEO     = 0x1005,
        SO_TYPE         = 0x1008
    }

    enum
    {
        SOMAXCONN       = 128
    }

    enum : uint
    {
        MSG_CTRUNC      = 0x20,
        MSG_DONTROUTE   = 0x4,
        MSG_EOR         = 0x8,
        MSG_OOB         = 0x1,
        MSG_PEEK        = 0x2,
        MSG_TRUNC       = 0x10,
        MSG_WAITALL     = 0x40
    }

    enum
    {
        AF_APPLETALK    = 16,
        AF_INET         = 2,
        AF_IPX          = 23,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0,
        PF_APPLETALK    = AF_APPLETALK,
        PF_IPX          = AF_IPX
    }

    enum
    {
        SHUT_RD,
        SHUT_WR,
        SHUT_RDWR
    }

    int     accept(int, scope sockaddr*, scope socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, scope sockaddr*, scope socklen_t*);
    int     getsockname(int, scope sockaddr*, scope socklen_t*);
    int     getsockopt(int, int, int, scope void*, scope socklen_t*);
    int     listen(int, int) @safe;
    ssize_t recv(int, scope void*, size_t, int);
    ssize_t recvfrom(int, scope void*, size_t, int, scope sockaddr*, scope socklen_t*);
    ssize_t recvmsg(int, scope msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int) @safe;
    int     socket(int, int, int) @safe;
    int     sockatmark(int) @safe;
    int     socketpair(int, int, int, ref int[2]) @safe;
}
else version (FreeBSD)
{
    alias uint   socklen_t;
    alias ubyte  sa_family_t;

    struct sockaddr
    {
        ubyte       sa_len;
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    private
    {
        enum _SS_ALIGNSIZE  = long.sizeof;
        enum _SS_MAXSIZE    = 128;
        enum _SS_PAD1SIZE   = _SS_ALIGNSIZE - ubyte.sizeof - sa_family_t.sizeof;
        enum _SS_PAD2SIZE   = _SS_MAXSIZE - ubyte.sizeof - sa_family_t.sizeof - _SS_PAD1SIZE - _SS_ALIGNSIZE;
    }

    struct sockaddr_storage
    {
         ubyte              ss_len;
         sa_family_t        ss_family;
         byte[_SS_PAD1SIZE] __ss_pad1;
         long               __ss_align;
         byte[_SS_PAD2SIZE] __ss_pad2;
    }

    struct msghdr
    {
        void*     msg_name;
        socklen_t msg_namelen;
        iovec*    msg_iov;
        int       msg_iovlen;
        void*     msg_control;
        socklen_t msg_controllen;
        int       msg_flags;
    }

    struct cmsghdr
    {
         socklen_t cmsg_len;
         int       cmsg_level;
         int       cmsg_type;
    }

    enum : uint
    {
        SCM_RIGHTS = 0x01
    }

    private // <machine/param.h>
    {
        enum _ALIGNBYTES = /+c_int+/ int.sizeof - 1;
        extern (D) size_t _ALIGN( size_t p ) { return (p + _ALIGNBYTES) & ~_ALIGNBYTES; }
    }

    extern (D) ubyte* CMSG_DATA( cmsghdr* cmsg )
    {
        return cast(ubyte*) cmsg + _ALIGN( cmsghdr.sizeof );
    }

    extern (D) cmsghdr* CMSG_NXTHDR( msghdr* mhdr, cmsghdr* cmsg )
    {
        if ( cmsg == null )
        {
           return CMSG_FIRSTHDR( mhdr );
        }
        else
        {
            if ( cast(ubyte*) cmsg + _ALIGN( cmsg.cmsg_len ) + _ALIGN( cmsghdr.sizeof ) >
                    cast(ubyte*) mhdr.msg_control + mhdr.msg_controllen )
                return null;
            else
                return cast(cmsghdr*) (cast(ubyte*) cmsg + _ALIGN( cmsg.cmsg_len ));
        }
    }

    extern (D) cmsghdr* CMSG_FIRSTHDR( msghdr* mhdr )
    {
        return mhdr.msg_controllen >= cmsghdr.sizeof ? cast(cmsghdr*) mhdr.msg_control : null;
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    enum
    {
        SOCK_DGRAM      = 2,
        SOCK_RDM        = 4,
        SOCK_SEQPACKET  = 5,
        SOCK_STREAM     = 1
    }

    enum : uint
    {
        SOL_SOCKET      = 0xffff
    }

    enum : uint
    {
        SO_ACCEPTCONN   = 0x0002,
        SO_BROADCAST    = 0x0020,
        SO_DEBUG        = 0x0001,
        SO_DONTROUTE    = 0x0010,
        SO_ERROR        = 0x1007,
        SO_KEEPALIVE    = 0x0008,
        SO_LINGER       = 0x0080,
        SO_NOSIGPIPE    = 0x0800, // non-standard
        SO_OOBINLINE    = 0x0100,
        SO_RCVBUF       = 0x1002,
        SO_RCVLOWAT     = 0x1004,
        SO_RCVTIMEO     = 0x1006,
        SO_REUSEADDR    = 0x0004,
        SO_REUSEPORT    = 0x0200,
        SO_SNDBUF       = 0x1001,
        SO_SNDLOWAT     = 0x1003,
        SO_SNDTIMEO     = 0x1005,
        SO_TYPE         = 0x1008
    }

    enum
    {
        SOMAXCONN       = 128
    }

    enum : uint
    {
        MSG_CTRUNC      = 0x20,
        MSG_DONTROUTE   = 0x4,
        MSG_EOR         = 0x8,
        MSG_OOB         = 0x1,
        MSG_PEEK        = 0x2,
        MSG_TRUNC       = 0x10,
        MSG_WAITALL     = 0x40,
        MSG_NOSIGNAL    = 0x20000
    }

    enum
    {
        AF_APPLETALK    = 16,
        AF_INET         = 2,
        AF_IPX          = 23,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0
    }

    enum
    {
        SHUT_RD = 0,
        SHUT_WR = 1,
        SHUT_RDWR = 2
    }

    int     accept(int, scope sockaddr*, scope socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, scope sockaddr*, scope socklen_t*);
    int     getsockname(int, scope sockaddr*, scope socklen_t*);
    int     getsockopt(int, int, int, scope void*, scope socklen_t*);
    int     listen(int, int) @safe;
    ssize_t recv(int, scope void*, size_t, int);
    ssize_t recvfrom(int, scope void*, size_t, int, scope sockaddr*, scope socklen_t*);
    ssize_t recvmsg(int, scope msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int) @safe;
    int     socket(int, int, int) @safe;
    int     sockatmark(int) @safe;
    int     socketpair(int, int, int, ref int[2]) @safe;
}
else version (NetBSD)
{
    alias uint   socklen_t;
    alias ubyte  sa_family_t;

    struct sockaddr
    {
        ubyte       sa_len;
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    private
    {
        enum _SS_ALIGNSIZE  = long.sizeof;
        enum _SS_MAXSIZE    = 128;
        enum _SS_PAD1SIZE   = _SS_ALIGNSIZE - ubyte.sizeof - sa_family_t.sizeof;
        enum _SS_PAD2SIZE   = _SS_MAXSIZE - ubyte.sizeof - sa_family_t.sizeof - _SS_PAD1SIZE - _SS_ALIGNSIZE;
    }

    struct sockaddr_storage
    {
         ubyte              ss_len;
         sa_family_t        ss_family;
         byte[_SS_PAD1SIZE] __ss_pad1;
         long               __ss_align;
         byte[_SS_PAD2SIZE] __ss_pad2;
    }

    struct msghdr
    {
        void*     msg_name;
        socklen_t msg_namelen;
        iovec*    msg_iov;
        int       msg_iovlen;
        void*     msg_control;
        socklen_t msg_controllen;
        int       msg_flags;
    }

    struct cmsghdr
    {
         socklen_t cmsg_len;
         int       cmsg_level;
         int       cmsg_type;
    }

    enum : uint
    {
        SCM_RIGHTS = 0x01
    }

    private // <machine/param.h>
    {
        enum _ALIGNBYTES = /+c_int+/ int.sizeof - 1;
        extern (D) size_t _ALIGN( size_t p ) { return (p + _ALIGNBYTES) & ~_ALIGNBYTES; }
    }

    extern (D) ubyte* CMSG_DATA( cmsghdr* cmsg )
    {
        return cast(ubyte*) cmsg + _ALIGN( cmsghdr.sizeof );
    }

    extern (D) cmsghdr* CMSG_NXTHDR( msghdr* mhdr, cmsghdr* cmsg )
    {
        if ( cmsg == null )
        {
           return CMSG_FIRSTHDR( mhdr );
        }
        else
        {
            if ( cast(ubyte*) cmsg + _ALIGN( cmsg.cmsg_len ) + _ALIGN( cmsghdr.sizeof ) >
                    cast(ubyte*) mhdr.msg_control + mhdr.msg_controllen )
                return null;
            else
                return cast(cmsghdr*) (cast(ubyte*) cmsg + _ALIGN( cmsg.cmsg_len ));
        }
    }

    extern (D) cmsghdr* CMSG_FIRSTHDR( msghdr* mhdr )
    {
        return mhdr.msg_controllen >= cmsghdr.sizeof ? cast(cmsghdr*) mhdr.msg_control : null;
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    enum
    {
        SOCK_DGRAM      = 2,
        SOCK_RDM        = 4,
        SOCK_SEQPACKET  = 5,
        SOCK_STREAM     = 1
    }

    enum : uint
    {
        SOL_SOCKET      = 0xffff
    }

    enum : uint
    {
         SO_DEBUG        = 0x0001,          /* turn on debugging info recording */
         SO_ACCEPTCONN   = 0x0002,          /* socket has had listen() */
         SO_REUSEADDR    = 0x0004,          /* allow local address reuse */
         SO_KEEPALIVE    = 0x0008,          /* keep connections alive */
         SO_DONTROUTE    = 0x0010,          /* just use interface addresses */
         SO_BROADCAST    = 0x0020,          /* permit sending of broadcast msgs */
         SO_USELOOPBACK  = 0x0040,          /* bypass hardware when possible */
         SO_LINGER       = 0x0080,          /* linger on close if data present */
         SO_OOBINLINE    = 0x0100,          /* leave received OOB data in line */
         SO_REUSEPORT    = 0x0200,          /* allow local address & port reuse */
        /*      SO_OTIMESTAMP   0x0400          */
         SO_NOSIGPIPE    = 0x0800,          /* no SIGPIPE from EPIPE */
         SO_ACCEPTFILTER = 0x1000,          /* there is an accept filter */
         SO_TIMESTAMP    = 0x2000,          /* timestamp received dgram traffic */

        /*
         * Additional options, not kept in so_options.
         */
         SO_SNDBUF       = 0x1001,          /* send buffer size */
         SO_RCVBUF       = 0x1002,          /* receive buffer size */
         SO_SNDLOWAT     = 0x1003,          /* send low-water mark */
         SO_RCVLOWAT     = 0x1004,          /* receive low-water mark */
        /* SO_OSNDTIMEO         0x1005 */
        /* SO_ORCVTIMEO         0x1006 */
         SO_ERROR        = 0x1007,          /* get error status and clear */
         SO_TYPE         = 0x1008,          /* get socket type */
         SO_OVERFLOWED   = 0x1009,          /* datagrams: return packets dropped */

         SO_NOHEADER     = 0x100a,          /* user supplies no header to kernel;
                                                 * kernel removes header and supplies
                                                 * payload
                                                 */
         SO_SNDTIMEO     = 0x100b,          /* send timeout */
         SO_RCVTIMEO     = 0x100c          /* receive timeout */

    }

    enum
    {
        SOMAXCONN       = 128
    }

    enum : uint
    {
         MSG_OOB         = 0x0001,          /* process out-of-band data */
         MSG_PEEK        = 0x0002,          /* peek at incoming message */
         MSG_DONTROUTE   = 0x0004,          /* send without using routing tables */
         MSG_EOR         = 0x0008,          /* data completes record */
         MSG_TRUNC       = 0x0010,          /* data discarded before delivery */
         MSG_CTRUNC      = 0x0020,          /* control data lost before delivery */
         MSG_WAITALL     = 0x0040,          /* wait for full request or error */
         MSG_DONTWAIT    = 0x0080,          /* this message should be nonblocking */
         MSG_BCAST       = 0x0100,          /* this message was rcvd using link-level brdcst */
         MSG_MCAST       = 0x0200,          /* this message was rcvd using link-level mcast */
         MSG_NOSIGNAL    = 0x0400          /* do not generate SIGPIPE on EOF */
    }

    enum
    {
        AF_APPLETALK    = 16,
        AF_INET         = 2,
        AF_IPX          = 23,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0
    }

    enum
    {
        SHUT_RD = 0,
        SHUT_WR = 1,
        SHUT_RDWR = 2
    }

    int     accept(int, scope sockaddr*, scope socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, scope sockaddr*, scope socklen_t*);
    int     getsockname(int, scope sockaddr*, scope socklen_t*);
    int     getsockopt(int, int, int, scope void*, scope socklen_t*);
    int     listen(int, int) @safe;
    ssize_t recv(int, scope void*, size_t, int);
    ssize_t recvfrom(int, scope void*, size_t, int, scope sockaddr*, scope socklen_t*);
    ssize_t recvmsg(int, scope msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int) @safe;
    int     socket(int, int, int) @safe;
    int     sockatmark(int) @safe;
    int     socketpair(int, int, int, ref int[2]) @safe;
}
else version (OpenBSD)
{
    alias uint   socklen_t;
    alias ubyte  sa_family_t;

    struct sockaddr
    {
        ubyte       sa_len;
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    struct sockaddr_storage
    {
         ubyte       ss_len;
         sa_family_t ss_family;
         byte[6]     __ss_pad1;
         long        __ss_align;
         byte[240]   __ss_pad2;
    }

    struct msghdr
    {
        void*     msg_name;
        socklen_t msg_namelen;
        iovec*    msg_iov;
        uint      msg_iovlen;
        void*     msg_control;
        socklen_t msg_controllen;
        int       msg_flags;
    }

    struct cmsghdr
    {
         socklen_t cmsg_len;
         int       cmsg_level;
         int       cmsg_type;
    }

    enum : uint
    {
        SCM_RIGHTS    = 0x01
    }

    private // <sys/_types.h>
    {
        extern (D) size_t _ALIGN(size_t p) { return (p + _ALIGNBYTES) & ~_ALIGNBYTES; }
    }

    extern (D) ubyte* CMSG_DATA(cmsghdr* cmsg)
    {
        return cast(ubyte*) cmsg + _ALIGN(cmsghdr.sizeof);
    }

    extern (D) cmsghdr* CMSG_NXTHDR(msghdr* mhdr, cmsghdr* cmsg)
    {
        if (cast(ubyte*) cmsg + _ALIGN(cmsg.cmsg_len) + _ALIGN(cmsghdr.sizeof) >
                cast(ubyte*) mhdr.msg_control + mhdr.msg_controllen)
            return null;
        else
            return cast(cmsghdr*) (cast(ubyte*) cmsg + _ALIGN(cmsg.cmsg_len));
    }

    extern (D) cmsghdr* CMSG_FIRSTHDR(msghdr* mhdr)
    {
        return mhdr.msg_controllen >= cmsghdr.sizeof ? cast(cmsghdr*) mhdr.msg_control : null;
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    enum
    {
        SOCK_DGRAM      = 2,
        SOCK_RDM        = 4,
        SOCK_SEQPACKET  = 5,
        SOCK_STREAM     = 1
    }

    enum : uint
    {
        SOL_SOCKET      = 0xffff
    }

    enum : uint
    {
         SO_DEBUG        = 0x0001,
         SO_ACCEPTCONN   = 0x0002,
         SO_REUSEADDR    = 0x0004,
         SO_KEEPALIVE    = 0x0008,
         SO_DONTROUTE    = 0x0010,
         SO_BROADCAST    = 0x0020,
         SO_USELOOPBACK  = 0x0040,
         SO_LINGER       = 0x0080,
         SO_OOBINLINE    = 0x0100,
         SO_REUSEPORT    = 0x0200,
         SO_TIMESTAMP    = 0x0800,
         SO_BINDANY      = 0x1000,
         SO_ZEROSIZE     = 0x2000,

         SO_SNDBUF       = 0x1001,
         SO_RCVBUF       = 0x1002,
         SO_SNDLOWAT     = 0x1003,
         SO_RCVLOWAT     = 0x1004,
         SO_SNDTIMEO     = 0x1005,
         SO_RCVTIMEO     = 0x1006,
         SO_ERROR        = 0x1007,
         SO_TYPE         = 0x1008,
         SO_NETPROC      = 0x1020,
         SO_RTABLE       = 0x1021,
         SO_PEERCRED     = 0x1022,
         SO_SPLICE       = 0x1023,
    }

    enum
    {
        SOMAXCONN       = 128
    }

    enum : uint
    {
         MSG_OOB          = 0x001,
         MSG_PEEK         = 0x002,
         MSG_DONTROUTE    = 0x004,
         MSG_EOR          = 0x008,
         MSG_TRUNC        = 0x010,
         MSG_CTRUNC       = 0x020,
         MSG_WAITALL      = 0x040,
         MSG_DONTWAIT     = 0x080,
         MSG_BCAST        = 0x100,
         MSG_MCAST        = 0x200,
         MSG_NOSIGNAL     = 0x400,
         MSG_CMSG_CLOEXEC = 0x800,
    }

    enum
    {
        AF_APPLETALK    = 16,
        AF_INET         = 2,
        AF_IPX          = 23,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0
    }

    enum
    {
        SHUT_RD = 0,
        SHUT_WR = 1,
        SHUT_RDWR = 2
    }

    int     accept(int, scope sockaddr*, scope socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, scope sockaddr*, scope socklen_t*);
    int     getsockname(int, scope sockaddr*, scope socklen_t*);
    int     getsockopt(int, int, int, scope void*, scope socklen_t*);
    int     listen(int, int) @safe;
    ssize_t recv(int, scope void*, size_t, int);
    ssize_t recvfrom(int, scope void*, size_t, int, scope sockaddr*, scope socklen_t*);
    ssize_t recvmsg(int, scope msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int) @safe;
    int     socket(int, int, int) @safe;
    int     sockatmark(int) @safe;
    int     socketpair(int, int, int, ref int[2]) @safe;
}
else version (DragonFlyBSD)
{
    alias uint   socklen_t;
    alias ubyte  sa_family_t;

    enum
    {
        SOCK_STREAM         = 1,
        SOCK_DGRAM          = 2,
        //SOCK_RAW          = 3,      // defined below
        SOCK_RDM            = 4,
        SOCK_SEQPACKET      = 5,
    }

    enum SOCK_CLOEXEC       = 0x10000000;
    enum SOCK_NONBLOCK      = 0x20000000;

    enum : uint
    {
        SO_DEBUG            = 0x0001,
        SO_ACCEPTCONN       = 0x0002,
        SO_REUSEADDR        = 0x0004,
        SO_KEEPALIVE        = 0x0008,
        SO_DONTROUTE        = 0x0010,
        SO_BROADCAST        = 0x0020,
        SO_USELOOPBACK      = 0x0040,
        SO_LINGER           = 0x0080,
        SO_OOBINLINE        = 0x0100,
        SO_REUSEPORT        = 0x0200,
        SO_TIMESTAMP        = 0x0400,
        SO_NOSIGPIPE        = 0x0800, // non-standard
        SO_ACCEPTFILTER     = 0x1000,

        SO_SNDBUF           = 0x1001,
        SO_RCVBUF           = 0x1002,
        SO_SNDLOWAT         = 0x1003,
        SO_RCVLOWAT         = 0x1004,
        SO_SNDTIMEO         = 0x1005,
        SO_RCVTIMEO         = 0x1006,
        SO_ERROR            = 0x1007,
        SO_TYPE             = 0x1008,
        SO_SNDSPACE         = 0x100a, // get appr. send buffer free space
        SO_CPUHINT          = 0x1030, // get socket's owner cpuid hint
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    struct  accept_filter_arg {
        byte[16] af_name;
        byte[256-16] af_arg;
    }

    enum : uint
    {
        SOL_SOCKET          = 0xffff
    }

    enum
    {
        AF_UNSPEC           = 0,
        AF_LOCAL            = 1,
        AF_UNIX             = AF_LOCAL,
        AF_INET             = 2,
        AF_APPLETALK        = 16,
        AF_IPX              = 23,
    }

    struct sockaddr
    {
        ubyte               sa_len;
        sa_family_t         sa_family;
        byte[14]            sa_data;
    }

    enum SOCK_MAXADDRLEN = 255;

    struct sockproto {
        ushort              sp_family;
        ushort              sp_protocol;
    }

    private
    {
        enum _SS_ALIGNSIZE  = long.sizeof;
        enum _SS_MAXSIZE    = 128;
        enum _SS_PAD1SIZE   = _SS_ALIGNSIZE - ubyte.sizeof - sa_family_t.sizeof;
        enum _SS_PAD2SIZE   = _SS_MAXSIZE - ubyte.sizeof - sa_family_t.sizeof - _SS_PAD1SIZE - _SS_ALIGNSIZE;
    }

    struct sockaddr_storage
    {
        ubyte              ss_len;
        sa_family_t        ss_family;
        byte[_SS_PAD1SIZE] __ss_pad1;
        long               __ss_align;
        byte[_SS_PAD2SIZE] __ss_pad2;
    }

    struct msghdr
    {
        void*               msg_name;
        socklen_t           msg_namelen;
        iovec*              msg_iov;
        int                 msg_iovlen;
        void*               msg_control;
        socklen_t           msg_controllen;
        int                 msg_flags;
    }

    enum SOMAXCONN          = 128;
    enum SOMAXOPT_SIZE      = 65536;
    enum SOMAXOPT_SIZE0     = (32 * 1024 * 1024);

    enum : uint
    {
        MSG_OOB             = 0x00000001,
        MSG_PEEK            = 0x00000002,
        MSG_DONTROUTE       = 0x00000004,
        MSG_EOR             = 0x00000008,
        MSG_TRUNC           = 0x00000010,
        MSG_CTRUNC          = 0x00000020,
        MSG_WAITALL         = 0x00000040,
        MSG_DONTWAIT        = 0x00000080,
        MSG_EOF             = 0x00000100,
        MSG_UNUSED09        = 0x00000200,
        MSG_NOSIGNAL        = 0x00000400,
        MSG_SYNC            = 0x00000800,
        MSG_CMSG_CLOEXEC    = 0x00001000,
        /* These override FIONBIO.  MSG_FNONBLOCKING is functionally equivalent to MSG_DONTWAIT.*/
        MSG_FBLOCKING       = 0x00010000,
        MSG_FNONBLOCKING    = 0x00020000,
        MSG_FMASK           = 0xFFFF0000,
    }

    struct cmsghdr
    {
         socklen_t          cmsg_len;
         int                cmsg_level;
         int                cmsg_type;
    }

    enum CMGROUP_MAX        = 16;

    struct cmsgcred {
            pid_t           cmcred_pid;
            uid_t           cmcred_uid;
            uid_t           cmcred_euid;
            gid_t           cmcred_gid;
            short           cmcred_ngroups;
            gid_t[CMGROUP_MAX] cmcred_groups;
    }

    enum : uint
    {
        SCM_RIGHTS = 0x01
    }

    private // <machine/param.h>
    {
        enum _ALIGNBYTES = /+c_int+/ int.sizeof - 1;
        extern (D) size_t _ALIGN( size_t p ) { return (p + _ALIGNBYTES) & ~_ALIGNBYTES; }
    }

    extern (D) ubyte* CMSG_DATA( cmsghdr* cmsg )
    {
        return cast(ubyte*) cmsg + _ALIGN( cmsghdr.sizeof );
    }

    extern (D) cmsghdr* CMSG_NXTHDR( msghdr* mhdr, cmsghdr* cmsg )
    {
        if ( cmsg == null )
        {
           return CMSG_FIRSTHDR( mhdr );
        }
        else
        {
            if ( cast(ubyte*) cmsg + _ALIGN( cmsg.cmsg_len ) + _ALIGN( cmsghdr.sizeof ) >
                    cast(ubyte*) mhdr.msg_control + mhdr.msg_controllen )
                return null;
            else
                return cast(cmsghdr*) (cast(ubyte*) cmsg + _ALIGN( cmsg.cmsg_len ));
        }
    }

    extern (D) cmsghdr* CMSG_FIRSTHDR( msghdr* mhdr )
    {
        return mhdr.msg_controllen >= cmsghdr.sizeof ? cast(cmsghdr*) mhdr.msg_control : null;
    }

    enum
    {
        SHUT_RD             = 0,
        SHUT_WR             = 1,
        SHUT_RDWR           = 2
    }

/*
    /+ sendfile(2) header/trailer struct +/
    struct sf_hdtr {
        iovec *             headers;
        int                 hdr_cnt;
        iovec *             trailers;
        int                 trl_cnt;
    }
*/

    int     accept(int, sockaddr*, socklen_t*);
//    int     accept4(int, sockaddr*, socklen_t*, int);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
//    int     extconnect(int, int, sockaddr*, socklen_t);
    int     getpeername(int, sockaddr*, socklen_t*);
    int     getsockname(int, sockaddr*, socklen_t*);
    int     getsockopt(int, int, int, void*, socklen_t*);
    int     listen(int, int);
    ssize_t recv(int, void*, size_t, int);
    ssize_t recvfrom(int, void*, size_t, int, sockaddr*, socklen_t*);
    ssize_t recvmsg(int, msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    ssize_t sendmsg(int, const scope msghdr*, int);
//    int     sendfile(int, int, off_t, size_t, sf_hdtr *, off_t *, int);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int);
    int     sockatmark(int);
    int     socket(int, int, int);
    int     socketpair(int, int, int, ref int[2]);
//  void    pfctlinput(int, struct sockaddr *);
}
else version (Solaris)
{
    alias uint socklen_t;
    alias ushort sa_family_t;

    struct sockaddr
    {
        sa_family_t sa_family;
        char[14] sa_data = 0;
    }

    alias double sockaddr_maxalign_t;

    private
    {
        enum _SS_ALIGNSIZE  = sockaddr_maxalign_t.sizeof;
        enum _SS_MAXSIZE    = 256;
        enum _SS_PAD1SIZE   = _SS_ALIGNSIZE - sa_family_t.sizeof;
        enum _SS_PAD2SIZE   = _SS_MAXSIZE - sa_family_t.sizeof + _SS_PAD1SIZE + _SS_ALIGNSIZE;
    }

    struct sockaddr_storage
    {
         sa_family_t ss_family;
         char[_SS_PAD1SIZE] _ss_pad1 = void;
         sockaddr_maxalign_t _ss_align;
         char[_SS_PAD2SIZE] _ss_pad2 = void;
    }

    struct msghdr
    {
        void* msg_name;
        socklen_t msg_namelen;
        iovec* msg_iov;
        int msg_iovlen;
        void* msg_control;
        socklen_t msg_controllen;
        int msg_flags;
    }

    struct cmsghdr
    {
         socklen_t cmsg_len;
         int cmsg_level;
         int cmsg_type;
    }

    enum : uint
    {
        SCM_RIGHTS = 0x1010
    }

    // FIXME: CMSG_DATA, CMSG_NXTHDR, CMSG_FIRSTHDR missing

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    enum
    {
        SOCK_STREAM = 2,
        SOCK_DGRAM = 1,
        SOCK_RDM = 5,
        SOCK_SEQPACKET = 6,
    }

    enum : uint
    {
        SOL_SOCKET      = 0xffff
    }

    enum : uint
    {
        SO_ACCEPTCONN   = 0x0002,
        SO_BROADCAST    = 0x0020,
        SO_DEBUG        = 0x0001,
        SO_DONTROUTE    = 0x0010,
        SO_ERROR        = 0x1007,
        SO_KEEPALIVE    = 0x0008,
        SO_LINGER       = 0x0080,
        SO_OOBINLINE    = 0x0100,
        SO_RCVBUF       = 0x1002,
        SO_RCVLOWAT     = 0x1004,
        SO_RCVTIMEO     = 0x1006,
        SO_REUSEADDR    = 0x0004,
        SO_SNDBUF       = 0x1001,
        SO_SNDLOWAT     = 0x1003,
        SO_SNDTIMEO     = 0x1005,
        SO_TYPE         = 0x1008,

        SO_USELOOPBACK  = 0x0040, // non-standard
        SO_DGRAM_ERRIND = 0x0200, // non-standard
        SO_RECVUCRED    = 0x0400, // non-standard
    }

    enum
    {
        SOMAXCONN = 128
    }

    enum : uint
    {
        MSG_CTRUNC      = 0x10,
        MSG_DONTROUTE   = 0x4,
        MSG_EOR         = 0x8,
        MSG_OOB         = 0x1,
        MSG_PEEK        = 0x2,
        MSG_TRUNC       = 0x20,
        MSG_WAITALL     = 0x40
    }

    enum
    {
        AF_IPX          = 23,
        AF_APPLETALK    = 16,
        AF_INET         = 2,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0
    }

    enum
    {
        SHUT_RD,
        SHUT_WR,
        SHUT_RDWR
    }

    int     accept(int, scope sockaddr*, scope socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, scope sockaddr*, scope socklen_t*);
    int     getsockname(int, scope sockaddr*, scope socklen_t*);
    int     getsockopt(int, int, int, scope void*, scope socklen_t*);
    int     listen(int, int) @safe;
    ssize_t recv(int, scope void*, size_t, int);
    ssize_t recvfrom(int, scope void*, size_t, int, scope sockaddr*, scope socklen_t*);
    ssize_t recvmsg(int, scope msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int) @safe;
    int     socket(int, int, int) @safe;
    int     sockatmark(int) @safe;
    int     socketpair(int, int, int, ref int[2]) @safe;
}
else version (CRuntime_Bionic)
{
    alias int    socklen_t;
    alias ushort sa_family_t;

    struct sockaddr
    {
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    private enum size_t _K_SS_MAXSIZE  = 128;

    struct sockaddr_storage
    {
        ushort ss_family;
        byte[_K_SS_MAXSIZE - ushort.sizeof] __data;
    }

    enum : uint
    {
        SCM_RIGHTS = 0x01
    }

    private enum _ALIGNBYTES = c_long.sizeof - 1;

    extern (D)
    {
        size_t CMSG_ALIGN( size_t len )
        {
            return (len + _ALIGNBYTES) & ~_ALIGNBYTES;
        }

        void* CMSG_DATA( cmsghdr* cmsg )
        {
            return cast(void*) (cast(char*) cmsg + CMSG_ALIGN( cmsghdr.sizeof ));
        }

        cmsghdr* CMSG_NXTHDR( msghdr* mhdr, cmsghdr* cmsg )
        {
            cmsghdr* __ptr = cast(cmsghdr*) ((cast(ubyte*) cmsg) + CMSG_ALIGN(cmsg.cmsg_len));
            return cast(c_ulong)( cast(char*)(__ptr+1) - cast(char*) mhdr.msg_control) > mhdr.msg_controllen ? null : __ptr;
        }

        cmsghdr* CMSG_FIRSTHDR( msghdr* mhdr )
        {
            return mhdr.msg_controllen >= cmsghdr.sizeof ? cast(cmsghdr*) mhdr.msg_control : null;
        }
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    struct msghdr
    {
        void*           msg_name;
        int             msg_namelen;
        iovec*          msg_iov;
        __kernel_size_t msg_iovlen;
        void*           msg_control;
        __kernel_size_t msg_controllen;
        uint            msg_flags;
    }

    struct cmsghdr
    {
        __kernel_size_t cmsg_len;
        int             cmsg_level;
        int             cmsg_type;
    }

    alias size_t __kernel_size_t;

    enum
    {
        SOCK_DGRAM      = 2,
        SOCK_SEQPACKET  = 5,
        SOCK_STREAM     = 1
    }

    enum
    {
        SOL_SOCKET      = 1
    }

    enum
    {
        SO_ACCEPTCONN   = 30,
        SO_BROADCAST    = 6,
        SO_DEBUG        = 1,
        SO_DONTROUTE    = 5,
        SO_ERROR        = 4,
        SO_KEEPALIVE    = 9,
        SO_LINGER       = 13,
        SO_OOBINLINE    = 10,
        SO_RCVBUF       = 8,
        SO_RCVLOWAT     = 18,
        SO_RCVTIMEO     = 20,
        SO_REUSEADDR    = 2,
        SO_SNDBUF       = 7,
        SO_SNDLOWAT     = 19,
        SO_SNDTIMEO     = 21,
        SO_TYPE         = 3
    }

    enum
    {
        SOMAXCONN       = 128
    }

    enum : uint
    {
        MSG_CTRUNC      = 0x08,
        MSG_DONTROUTE   = 0x04,
        MSG_EOR         = 0x80,
        MSG_OOB         = 0x01,
        MSG_PEEK        = 0x02,
        MSG_TRUNC       = 0x20,
        MSG_WAITALL     = 0x100
    }

    enum
    {
        AF_APPLETALK    = 5,
        AF_INET         = 2,
        AF_IPX          = 4,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0
    }

    enum
    {
        SHUT_RD,
        SHUT_WR,
        SHUT_RDWR
    }

    enum SOCK_RDM = 4;

    int     accept(int, scope sockaddr*, scope socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, scope sockaddr*, scope socklen_t*);
    int     getsockname(int, scope sockaddr*, scope socklen_t*);
    int     getsockopt(int, int, int, scope void*, scope socklen_t*);
    int     listen(int, int) @safe;
    ssize_t recv(int, scope void*, size_t, int);
    ssize_t recvfrom(int, scope void*, size_t, int, scope sockaddr*, scope socklen_t*);
    int     recvmsg(int, scope msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    int     sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int) @safe;
    int     socket(int, int, int) @safe;
    int     sockatmark(int) @safe;
    int     socketpair(int, int, int, ref int[2]) @safe;
}
else version (CRuntime_Musl)
{
    alias uint socklen_t;
    alias ushort sa_family_t;

    struct sockaddr
    {
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    private enum : size_t
    {
        _SS_SIZE    = 128,
        _SS_PADSIZE = _SS_SIZE - c_ulong.sizeof - sa_family_t.sizeof
    }

    struct sockaddr_storage
    {
        sa_family_t ss_family;
        byte[_SS_PADSIZE] __ss_padding;
        c_ulong     __ss_align;
    }

    enum
    {
        SOCK_STREAM = 1,
        SOCK_DGRAM = 2,
        SOCK_RDM = 4,
        SOCK_SEQPACKET = 5,
        SOCK_DCCP = 6,
        SOCK_PACKET = 10
    }
    enum
    {
        AF_UNSPEC       = 0,
        AF_LOCAL        = 1,
        AF_UNIX         = AF_LOCAL,
        AF_FILE         = AF_LOCAL,
        AF_INET         = 2,
        AF_AX25         = 3,
        AF_IPX          = 4,
        AF_APPLETALK    = 5,
        PF_APPLETALK    = AF_APPLETALK,
        PF_IPX          = AF_IPX
    }

    enum
    {
        SHUT_RD,
        SHUT_WR,
        SHUT_RDWR
    }

    enum
    {
        SOL_SOCKET      = 1
    }

    enum
    {
        SO_DEBUG        = 1
    }

    version (MIPS_Any)
    {
        enum
        {
            SO_REUSEADDR    = 0x0004,
            SO_TYPE         = 0x1008,
            SO_ERROR        = 0x1007,
            SO_DONTROUTE    = 0x0010,
            SO_BROADCAST    = 0x0020,
            SO_SNDBUF       = 0x1001,
            SO_RCVBUF       = 0x1002,
            SO_KEEPALIVE    = 0x0008,
            SO_OOBINLINE    = 0x0100,
            SO_LINGER       = 0x0080,
            SO_REUSEPORT    = 0x0200,
            SO_RCVLOWAT     = 0x1004,
            SO_SNDLOWAT     = 0x1003,
            SO_RCVTIMEO     = 0x1006,
            SO_SNDTIMEO     = 0x1005,
            SO_ACCEPTCONN   = 0x1009
        }
    }
    else
    {
        enum
        {
            SO_REUSEADDR    = 2,
            SO_TYPE         = 3,
            SO_ERROR        = 4,
            SO_DONTROUTE    = 5,
            SO_BROADCAST    = 6,
            SO_SNDBUF       = 7,
            SO_RCVBUF       = 8,
            SO_KEEPALIVE    = 9,
            SO_OOBINLINE    = 10,
            SO_LINGER       = 13,
            SO_REUSEPORT    = 15,
            SO_RCVLOWAT     = 18,
            SO_SNDLOWAT     = 19,
            SO_RCVTIMEO     = 20,
            SO_SNDTIMEO     = 21,
            SO_ACCEPTCONN   = 30
        }
    }

    enum : uint
    {
        MSG_OOB         = 0x01,
        MSG_PEEK        = 0x02,
        MSG_DONTROUTE   = 0x04,
        MSG_CTRUNC      = 0x08,
        MSG_TRUNC       = 0x20,
        MSG_EOR         = 0x80,
        MSG_WAITALL     = 0x100,
        MSG_NOSIGNAL    = 0x4000
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }
    struct msghdr {
        void *msg_name;
        socklen_t msg_namelen;
        iovec *msg_iov;
        int msg_iovlen, __pad1;
        void *msg_control;
        socklen_t msg_controllen, __pad2;
        int msg_flags;
    }
    int     accept(int, sockaddr*, socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, sockaddr*, socklen_t*);
    int     getsockname(int, sockaddr*, socklen_t*);
    int     getsockopt(int, int, int, void*, socklen_t*);
    int     listen(int, int);
    ssize_t recv(int, void*, size_t, int);
    ssize_t recvfrom(int, void*, size_t, int, sockaddr*, socklen_t*);
    ssize_t recvmsg(int, msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int);
    int     socket(int, int, int);
    int     sockatmark(int);
    int     socketpair(int, int, int, ref int[2]);
}
else version (CRuntime_UClibc)
{
    alias uint   socklen_t;
    alias ushort sa_family_t;

    struct sockaddr
    {
        sa_family_t sa_family;
        byte[14]    sa_data;
    }

    private enum : size_t
    {
        _SS_SIZE    = 128,
        _SS_PADSIZE = _SS_SIZE - (c_ulong.sizeof * 2)
    }

    struct sockaddr_storage
    {
        sa_family_t ss_family;
        c_ulong     __ss_align;
        byte[_SS_PADSIZE] __ss_padding;
    }

    struct msghdr
    {
        void*     msg_name;
        socklen_t msg_namelen;
        iovec*    msg_iov;
        size_t    msg_iovlen;
        void*     msg_control;
        size_t    msg_controllen;
        int       msg_flags;
    }

    struct cmsghdr
    {
        size_t cmsg_len;
        int    cmsg_level;
        int    cmsg_type;
    }

    enum : uint
    {
        SCM_RIGHTS = 0x01
    }

    extern (D) inout(ubyte)*   CMSG_DATA( inout(cmsghdr)* cmsg ) pure nothrow @nogc { return cast(ubyte*)( cmsg + 1 ); }

    private inout(cmsghdr)* __cmsg_nxthdr(inout(msghdr)*, inout(cmsghdr)*) pure nothrow @nogc;
    extern (D)  inout(cmsghdr)* CMSG_NXTHDR(inout(msghdr)* msg, inout(cmsghdr)* cmsg) pure nothrow @nogc
    {
        return __cmsg_nxthdr(msg, cmsg);
    }

    extern (D) inout(cmsghdr)* CMSG_FIRSTHDR( inout(msghdr)* mhdr ) pure nothrow @nogc
    {
        return ( cast(size_t)mhdr.msg_controllen >= cmsghdr.sizeof
                             ? cast(inout(cmsghdr)*) mhdr.msg_control
                             : cast(inout(cmsghdr)*) null );
    }

    extern (D)
    {
        size_t CMSG_ALIGN( size_t len ) pure nothrow @nogc
        {
            return (len + size_t.sizeof - 1) & cast(size_t) (~(size_t.sizeof - 1));
        }

        size_t CMSG_LEN( size_t len ) pure nothrow @nogc
        {
            return CMSG_ALIGN(cmsghdr.sizeof) + len;
        }
    }

    extern (D) size_t CMSG_SPACE(size_t len) pure nothrow @nogc
    {
        return CMSG_ALIGN(len) + CMSG_ALIGN(cmsghdr.sizeof);
    }

    struct linger
    {
        int l_onoff;
        int l_linger;
    }

    version (X86_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1,
            SOCK_CLOEXEC    = 0x80000, // octal 02000000
            SOCK_NONBLOCK   = 0x800 // octal 00004000
        }
    }
    else version (MIPS_Any)
    {
        enum
        {
            SOCK_DGRAM      = 1,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 2,
            SOCK_CLOEXEC    = 0x80000, // octal 02000000
            SOCK_NONBLOCK   = 0x80 // octal 00000200
        }
    }
    else version (ARM_Any)
    {
        enum
        {
            SOCK_DGRAM      = 2,
            SOCK_SEQPACKET  = 5,
            SOCK_STREAM     = 1,
            SOCK_CLOEXEC    = 0x80000, // octal 02000000
            SOCK_NONBLOCK   = 0x800 // octal 00004000
        }
    }
    else
        static assert(0, "unimplemented");

    enum
    {
        SO_ACCEPTCONN   = 30,
        SO_BROADCAST    = 6,
        SO_DEBUG        = 1,
        SO_DONTROUTE    = 5,
        SO_ERROR        = 4,
        SO_KEEPALIVE    = 9,
        SO_LINGER       = 13,
        SO_OOBINLINE    = 10,
        SO_RCVBUF       = 8,
        SO_RCVLOWAT     = 18,
        SO_RCVTIMEO     = 20,
        SO_REUSEADDR    = 2,
        SO_SNDBUF       = 7,
        SO_SNDLOWAT     = 19,
        SO_SNDTIMEO     = 21,
        SO_TYPE         = 3,

        SOL_SOCKET      = 1,
        SOL_TCP         = 6,
        SOMAXCONN       = 128
    }

    enum : uint
    {
        MSG_CTRUNC      = 0x08,
        MSG_DONTROUTE   = 0x04,
        MSG_EOR         = 0x80,
        MSG_OOB         = 0x01,
        MSG_PEEK        = 0x02,
        MSG_TRUNC       = 0x20,
        MSG_WAITALL     = 0x100,
        MSG_NOSIGNAL    = 0x4000
    }

    enum
    {
        AF_APPLETALK    = 5,
        AF_INET         = 2,
        AF_IPX          = 4,
        AF_UNIX         = 1,
        AF_UNSPEC       = 0,
        PF_APPLETALK    = AF_APPLETALK,
        PF_IPX          = AF_IPX
    }

    enum int SOCK_RDM   = 4;

    enum
    {
        SHUT_RD,
        SHUT_WR,
        SHUT_RDWR
    }

    int     accept(int, sockaddr*, socklen_t*);
    int     bind(int, const scope sockaddr*, socklen_t);
    int     connect(int, const scope sockaddr*, socklen_t);
    int     getpeername(int, sockaddr*, socklen_t*);
    int     getsockname(int, sockaddr*, socklen_t*);
    int     getsockopt(int, int, int, void*, socklen_t*);
    int     listen(int, int);
    ssize_t recv(int, void*, size_t, int);
    ssize_t recvfrom(int, void*, size_t, int, sockaddr*, socklen_t*);
    ssize_t recvmsg(int, msghdr*, int);
    ssize_t send(int, const scope void*, size_t, int);
    ssize_t sendmsg(int, const scope msghdr*, int);
    ssize_t sendto(int, const scope void*, size_t, int, const scope sockaddr*, socklen_t);
    int     setsockopt(int, int, int, const scope void*, socklen_t);
    int     shutdown(int, int);
    int     socket(int, int, int);
    int     sockatmark(int);
    int     socketpair(int, int, int, ref int[2]);
}
else
{
    static assert(false, "Unsupported platform");
}

//
// IPV6 (IP6)
//
/*
AF_INET6
*/

version (CRuntime_Glibc)
{
    enum
    {
        AF_INET6    = 10
    }
}
else version (Darwin)
{
    enum
    {
        AF_INET6    = 30
    }
}
else version (FreeBSD)
{
    enum
    {
        AF_INET6    = 28
    }
}
else version (NetBSD)
{
    enum
    {
        AF_INET6    = 24
    }
}
else version (OpenBSD)
{
    enum
    {
        AF_INET6    = 24
    }
}
else version (DragonFlyBSD)
{
    enum
    {
        AF_INET6    = 28
    }
}
else version (Solaris)
{
    enum
    {
        AF_INET6 = 26,
    }
}
else version (CRuntime_Bionic)
{
    enum
    {
        AF_INET6    = 10
    }
}
else version (CRuntime_Musl)
{
    enum AF_INET6 = 10;
}
else version (CRuntime_UClibc)
{
    enum
    {
        AF_INET6    = 10
    }
}
else
{
    static assert(false, "Unsupported platform");
}

//
// Raw Sockets (RS)
//
/*
SOCK_RAW
*/

version (CRuntime_Glibc)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (Darwin)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (FreeBSD)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (NetBSD)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (OpenBSD)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (DragonFlyBSD)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (Solaris)
{
    enum
    {
        SOCK_RAW = 4,
    }
}
else version (CRuntime_Bionic)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (CRuntime_Musl)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else version (CRuntime_UClibc)
{
    enum
    {
        SOCK_RAW    = 3
    }
}
else
{
    static assert(false, "Unsupported platform");
}
