github.com/labulakalia/water@v0.0.5-0.20231118024244-f351ca6784b6/if.go (about)

     1  package water
     2  
     3  import (
     4  	"errors"
     5  	"io"
     6  )
     7  
     8  // Interface is a TUN/TAP interface.
     9  //
    10  // MultiQueue(Linux kernel > 3.8): With MultiQueue enabled, user should hold multiple
    11  // interfaces to send/receive packet in parallel.
    12  // Kernel document about MultiQueue: https://www.kernel.org/doc/Documentation/networking/tuntap.txt
    13  type Interface struct {
    14  	isTAP bool
    15  	io.ReadWriteCloser
    16  	name string
    17  }
    18  
    19  // DeviceType is the type for specifying device types.
    20  type DeviceType int
    21  
    22  // TUN and TAP device types.
    23  const (
    24  	_ = iota
    25  	TUN
    26  	TAP
    27  )
    28  
    29  // Config defines parameters required to create a TUN/TAP interface. It's only
    30  // used when the device is initialized. A zero-value Config is a valid
    31  // configuration.
    32  type Config struct {
    33  	// DeviceType specifies whether the device is a TUN or TAP interface. A
    34  	// zero-value is treated as TUN.
    35  	DeviceType DeviceType
    36  
    37  	// PlatformSpecificParams defines parameters that differ on different
    38  	// platforms. See comments for the type for more details.
    39  	PlatformSpecificParams
    40  }
    41  
    42  func defaultConfig() Config {
    43  	return Config{
    44  		DeviceType:             TUN,
    45  		PlatformSpecificParams: defaultPlatformSpecificParams(),
    46  	}
    47  }
    48  
    49  var zeroConfig Config
    50  
    51  // New creates a new TUN/TAP interface using config.
    52  func New(config Config) (ifce *Interface, err error) {
    53  	if zeroConfig == config {
    54  		config = defaultConfig()
    55  	}
    56  	if config.PlatformSpecificParams == zeroConfig.PlatformSpecificParams {
    57  		config.PlatformSpecificParams = defaultPlatformSpecificParams()
    58  	}
    59  	switch config.DeviceType {
    60  	case TUN, TAP:
    61  		return openDev(config)
    62  	default:
    63  		return nil, errors.New("unknown device type")
    64  	}
    65  }
    66  
    67  // IsTUN returns true if ifce is a TUN interface.
    68  func (ifce *Interface) IsTUN() bool {
    69  	return !ifce.isTAP
    70  }
    71  
    72  // IsTAP returns true if ifce is a TAP interface.
    73  func (ifce *Interface) IsTAP() bool {
    74  	return ifce.isTAP
    75  }
    76  
    77  // Name returns the interface name of ifce, e.g. tun0, tap1, tun0, etc..
    78  func (ifce *Interface) Name() string {
    79  	return ifce.name
    80  }