//
// 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

	"EDESTADDRREQ":    EDESTADDRREQ,
	"EMSGSIZE":        EMSGSIZE,
	"EPROTOTYPE":      EPROTOTYPE,
	"ENOPROTOOPT":     ENOPROTOOPT,
	"EPROTONOSUPPORT": EPROTONOSUPPORT,
	"ESOCKTNOSUPPORT": ESOCKTNOSUPPORT,
	"EOPNOTSUPP":      EOPNOTSUPP,
	"EPFNOSUPPORT":    EPFNOSUPPORT,
	"EAFNOSUPPORT":    EAFNOSUPPORT,
	"EADDRINUSE":      EADDRINUSE,
	"EADDRNOTAVAIL":   EADDRNOTAVAIL,
	"ENETDOWN":        ENETDOWN,
	"ENETUNREACH":     ENETUNREACH,

}

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

	ENONET
	ENOPKG
	ENOPROTOOPT
	ENOSPC
	ENOSR
	ENOSTR
	ENOSYS
	ENOTBLK
	ENOTCONN
	ENOTEMPTY
	ENOTNAM
	ENOTRECOVERABLE
	ENOTSOCK
	ENOTSUP
	ENOTTY
	ENOTUNIQ
	ENXIO
	EOPNOTSUPP
	EOVERFLOW
	EOWNERDEAD
	EPERM
	EPFNOSUPPORT
	EPIPE
	EPROTO
	EPROTONOSUPPORT
	EPROTOTYPE
	ERANGE
	EREMCHG
	EREMOTE
	EREMOTEIO
	ERESTART
	EROFS
	ESHUTDOWN

	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
}