//
// Kernel >= 5.16 returns EOPNOTSUPP/ENOPROTOOPT in case of fallback.
// Older kernels will always return them even if MPTCP is used: not usable.
func hasFallenBack(fd *netFD) bool {
	_, err := fd.pfd.GetsockoptInt(_SOL_MPTCP, _MPTCP_INFO)

	// 2 expected errors in case of fallback depending on the address family
	//   - AF_INET:  EOPNOTSUPP
	//   - AF_INET6: ENOPROTOOPT

// license that can be found in the LICENSE file.

//go:build !plan9 && !windows

package net

import (
	"errors"
	"os"
	"syscall"
)

var (
	errOpNotSupported = syscall.EOPNOTSUPP

	abortedConnRequestErrors = []error{syscall.ECONNABORTED} // see accept in fd_unix.go
)

func isPlatformError(err error) bool {
	_, ok := err.(syscall.Errno)
	return ok
}

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package net

import (
	"errors"
	"syscall"
)

var (
	errOpNotSupported = syscall.EOPNOTSUPP

	abortedConnRequestErrors = []error{syscall.ERROR_NETNAME_DELETED, syscall.WSAECONNRESET} // see accept in fd_windows.go
)

func isPlatformError(err error) bool {
	_, ok := err.(syscall.Errno)
	return ok
}

			// any data, so we can tell the caller that we
			// couldn't handle the transfer and let them fall
			// back to more generic code.
			return 0, false, nil
		case syscall.EXDEV, syscall.EINVAL, syscall.EIO, syscall.EOPNOTSUPP, syscall.EPERM:
			// Prior to Linux 5.3, it was not possible to
			// copy_file_range across file systems. Similarly to
			// the ENOSYS case above, if we see EXDEV, we have

}

func fileListenNet(filetype syscall.Filetype) (string, error) {
	switch filetype {
	case syscall.FILETYPE_SOCKET_STREAM:
		return "tcp", nil
	case syscall.FILETYPE_SOCKET_DGRAM:
		return "", syscall.EOPNOTSUPP
	default:
		return "", syscall.ENOTSOCK
	}
}

func fileConnNet(filetype syscall.Filetype) (string, error) {
	switch filetype {
	case syscall.FILETYPE_SOCKET_STREAM:
		return "tcp", nil

	tests := []struct {
		filetype syscall.Filetype
		network  string
		error    error
	}{
		{syscall.FILETYPE_SOCKET_STREAM, "tcp", nil},
		{syscall.FILETYPE_SOCKET_DGRAM, "", syscall.EOPNOTSUPP},
		{syscall.FILETYPE_BLOCK_DEVICE, "", syscall.ENOTSOCK},
		{syscall.FILETYPE_CHARACTER_DEVICE, "", syscall.ENOTSOCK},
		{syscall.FILETYPE_DIRECTORY, "", syscall.ENOTSOCK},

	ESRCH           Errno = 71
	ESTALE          Errno = 72
	ETIMEDOUT       Errno = 73
	ETXTBSY         Errno = 74
	EXDEV           Errno = 75
	ENOTCAPABLE     Errno = 76
	// needed by src/net/error_unix_test.go
	EOPNOTSUPP = ENOTSUP
)

// TODO: Auto-generate some day. (Hard-coded in binaries so not likely to change.)
var errorstr = [...]string{
	E2BIG:           "Argument list too long",
	EACCES:          "Permission denied",

	case oserror.ErrExist:
		return e == EEXIST || e == ENOTEMPTY
	case oserror.ErrNotExist:
		return e == ENOENT
	case errorspkg.ErrUnsupported:
		return e == ENOSYS || e == ENOTSUP || e == EOPNOTSUPP
	}
	return false
}

func (e Errno) Temporary() bool {
	return e == EINTR || e == EMFILE || e.Timeout()
}

func (e Errno) Timeout() bool {
	return e == EAGAIN || e == EWOULDBLOCK || e == ETIMEDOUT
}

		t.Errorf("Fchmodat: failed to change mode: expected %v, got %v", 0444, fi.Mode())
	}

	err = syscall.Fchmodat(_AT_FDCWD, "symlink1", 0444, _AT_SYMLINK_NOFOLLOW)
	if err != syscall.EOPNOTSUPP {
		t.Fatalf("Fchmodat: unexpected error: %v, expected EOPNOTSUPP", err)
	}
}

func TestMain(m *testing.M) {
	if os.Getenv("GO_DEATHSIG_PARENT") == "1" {
		deathSignalParent()
	} else if os.Getenv("GO_DEATHSIG_CHILD") == "1" {

	ENOTRUST        = syscall.Errno(0x72)
	ENOTSOCK        = syscall.Errno(0x39)
	ENOTSUP         = syscall.Errno(0x7c)
	ENOTTY          = syscall.Errno(0x19)
	ENXIO           = syscall.Errno(0x6)
	EOPNOTSUPP      = syscall.Errno(0x40)
	EOVERFLOW       = syscall.Errno(0x7f)
	EOWNERDEAD      = syscall.Errno(0x5f)
	EPERM           = syscall.Errno(0x1)
	EPFNOSUPPORT    = syscall.Errno(0x41)