github.com/GFW-knocker/wireguard@v1.0.1/tun/tun.go (about) 1 /* SPDX-License-Identifier: MIT 2 * 3 * Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved. 4 */ 5 6 package tun 7 8 import ( 9 "os" 10 ) 11 12 type Event int 13 14 const ( 15 EventUp = 1 << iota 16 EventDown 17 EventMTUUpdate 18 ) 19 20 type Device interface { 21 // File returns the file descriptor of the device. 22 File() *os.File 23 24 // Read one or more packets from the Device (without any additional headers). 25 // On a successful read it returns the number of packets read, and sets 26 // packet lengths within the sizes slice. len(sizes) must be >= len(bufs). 27 // A nonzero offset can be used to instruct the Device on where to begin 28 // reading into each element of the bufs slice. 29 Read(bufs [][]byte, sizes []int, offset int) (n int, err error) 30 31 // Write one or more packets to the device (without any additional headers). 32 // On a successful write it returns the number of packets written. A nonzero 33 // offset can be used to instruct the Device on where to begin writing from 34 // each packet contained within the bufs slice. 35 Write(bufs [][]byte, offset int) (int, error) 36 37 // MTU returns the MTU of the Device. 38 MTU() (int, error) 39 40 // Name returns the current name of the Device. 41 Name() (string, error) 42 43 // Events returns a channel of type Event, which is fed Device events. 44 Events() <-chan Event 45 46 // Close stops the Device and closes the Event channel. 47 Close() error 48 49 // BatchSize returns the preferred/max number of packets that can be read or 50 // written in a single read/write call. BatchSize must not change over the 51 // lifetime of a Device. 52 BatchSize() int 53 }