1 files changed, 32 insertions, 8 deletions
diff --git a/tun/tun.go b/tun/tun.go
index 01051b9..e203ba8 100644
--- a/tun/tun.go
+++ b/tun/tun.go
@@ -18,12 +18,36 @@ const (
 )
 
 type Device interface {
-	File() *os.File                 // returns the file descriptor of the device
-	Read([]byte, int) (int, error)  // read a packet from the device (without any additional headers)
-	Write([]byte, int) (int, error) // writes a packet to the device (without any additional headers)
-	Flush() error                   // flush all previous writes to the device
-	MTU() (int, error)              // returns the MTU of the device
-	Name() (string, error)          // fetches and returns the current name
-	Events() <-chan Event           // returns a constant channel of events related to the device
-	Close() error                   // stops the device and closes the event channel
+	// File returns the file descriptor of the device.
+	File() *os.File
+
+	// Read one or more packets from the Device (without any additional headers).
+	// On a successful read it returns the number of packets read, and sets
+	// packet lengths within the sizes slice. len(sizes) must be >= len(buffs).
+	// A nonzero offset can be used to instruct the Device on where to begin
+	// reading into each element of the buffs slice.
+	Read(buffs [][]byte, sizes []int, offset int) (n int, err error)
+
+	// Write one or more packets to the device (without any additional headers).
+	// On a successful write it returns the number of packets written. A nonzero
+	// offset can be used to instruct the Device on where to begin writing from
+	// each packet contained within the buffs slice.
+	Write(buffs [][]byte, offset int) (int, error)
+
+	// MTU returns the MTU of the Device.
+	MTU() (int, error)
+
+	// Name returns the current name of the Device.
+	Name() (string, error)
+
+	// Events returns a channel of type Event, which is fed Device events.
+	Events() <-chan Event
+
+	// Close stops the Device and closes the Event channel.
+	Close() error
+
+	// BatchSize returns the preferred/max number of packets that can be read or
+	// written in a single read/write call. BatchSize must not change over the
+	// lifetime of a Device.
+	BatchSize() int
 }