poll.CloseFunc(s)
		return nil, os.NewSyscallError("getsockopt", err)
	}
	lsa, _ := syscall.Getsockname(s)
	rsa, _ := syscall.Getpeername(s)
	switch lsa.(type) {
	case *syscall.SockaddrInet4:
		family = syscall.AF_INET
	case *syscall.SockaddrInet6:
		family = syscall.AF_INET6
	case *syscall.SockaddrUnix:
		family = syscall.AF_UNIX
	default:
		poll.CloseFunc(s)
		return nil, syscall.EPROTONOSUPPORT
	}

}

var (
	supportTCPKeepAliveIdle     bool
	supportTCPKeepAliveInterval bool
	supportTCPKeepAliveCount    bool
)

var initTCPKeepAlive = sync.OnceFunc(func() {
	s, err := WSASocket(syscall.AF_INET, syscall.SOCK_STREAM, syscall.IPPROTO_TCP, nil, 0, WSA_FLAG_NO_HANDLE_INHERIT)
	if err != nil {
		// Fallback to checking the Windows version.
		major, _, build := version()

	}
	return nil
}

func (a *TCPAddr) family() int {
	if a == nil || len(a.IP) <= IPv4len {
		return syscall.AF_INET
	}
	if a.IP.To4() != nil {
		return syscall.AF_INET
	}
	return syscall.AF_INET6
}

func (a *TCPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {
		return nil, nil
	}

			}
			// Route all packets marked in chain ISTIODIVERT using routing table ${INBOUND_TPROXY_ROUTE_TABLE}.
			// Equivalent to `ip rule add fwmark <tproxyMark> lookup <tproxyTable>`
			families := []int{unix.AF_INET}
			if cfg.EnableIPv6 {
				families = append(families, unix.AF_INET6)
			}
			for _, family := range families {
				r := netlink.NewRule()
				r.Family = family
				r.Table = tproxyTable
				r.Mark = tproxyMark

		fd := ln.(*TCPListener).fd
		if err := checkDualStackAddrFamily(fd); err != nil {
			return err
		}
	case "tcp4":
		fd := ln.(*TCPListener).fd
		if fd.family != syscall.AF_INET {
			return fmt.Errorf("%v got %v; want %v", fd.laddr, fd.family, syscall.AF_INET)
		}
	case "tcp6":
		fd := ln.(*TCPListener).fd
		if fd.family != syscall.AF_INET6 {
			return fmt.Errorf("%v got %v; want %v", fd.laddr, fd.family, syscall.AF_INET6)
		}

// for socket() system call, returns true if affirmative.
var SupportSockNonblockCloexec = sync.OnceValue(func() bool {
	// First test if socket() supports SOCK_NONBLOCK and SOCK_CLOEXEC directly.
	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, 0)
	if err == nil {
		syscall.Close(s)
		return true
	}
	if err != syscall.EPROTONOSUPPORT && err != syscall.EINVAL {

	return forEachInpodMarkIPRule(cfg, netlink.RuleDel)
}

func forEachInpodMarkIPRule(cfg *Config, f func(*netlink.Rule) error) error {
	var rules []*netlink.Rule
	families := []int{unix.AF_INET}
	if cfg.EnableIPv6 {
		families = append(families, unix.AF_INET6)
	}
	for _, family := range families {
		// Equiv:
		// ip rule add fwmark 0x111/0xfff pref 32764 lookup 100
		//

	}
	// Sub Flags to 0x2
	// 011 -> 001, 010 -> 000
	vs.Flags = ServiceFlags(svc.Flags &^ uint32(FlagHashed))

	if vs.Address == nil {
		if svc.AddressFamily == unix.AF_INET {
			vs.Address = net.IPv4zero
		} else {
			vs.Address = net.IPv6zero
		}
	}
	return vs, nil
}

// toRealServer converts an IPVS Destination to the equivalent RealServer structure.

	}
}

func canCreateMPTCPSocket() bool {
	// We want to know if we can create an MPTCP socket, not just if it is
	// available (mptcpAvailable()): it could be blocked by the admin
	fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM, _IPPROTO_MPTCP)
	if err != nil {
		return false
	}

	syscall.Close(fd)
	return true
}

func testMultiPathTCP(t *testing.T, envVar bool) {
	if envVar {

			err = checkFileIsNotPartOfNetpoll(f)
			if err != nil {
				t.Fatal(err)
			}
		})
	}
}

func TestWSASocketConflict(t *testing.T) {
	s, err := windows.WSASocket(syscall.AF_INET, syscall.SOCK_STREAM, syscall.IPPROTO_TCP, nil, 0, windows.WSA_FLAG_OVERLAPPED)
	if err != nil {
		t.Fatal(err)
	}
	fd := poll.FD{Sysfd: s, IsStream: true, ZeroReadIsEOF: true}
	_, err = fd.Init("tcp", true)