64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
// Copyright 2018 The gVisor Authors.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
// +build linux
|
|
|
|
// Package tun contains methods to open TAP and TUN devices.
|
|
package tun
|
|
|
|
import (
|
|
"syscall"
|
|
"unsafe"
|
|
)
|
|
|
|
// Open opens the specified TUN device, sets it to non-blocking mode, and
|
|
// returns its file descriptor.
|
|
func Open(name string) (int, error) {
|
|
return open(name, syscall.IFF_TUN|syscall.IFF_NO_PI)
|
|
}
|
|
|
|
// OpenTAP opens the specified TAP device, sets it to non-blocking mode, and
|
|
// returns its file descriptor.
|
|
func OpenTAP(name string) (int, error) {
|
|
return open(name, syscall.IFF_TAP|syscall.IFF_NO_PI)
|
|
}
|
|
|
|
func open(name string, flags uint16) (int, error) {
|
|
fd, err := syscall.Open("/dev/net/tun", syscall.O_RDWR, 0)
|
|
if err != nil {
|
|
return -1, err
|
|
}
|
|
|
|
var ifr struct {
|
|
name [16]byte
|
|
flags uint16
|
|
_ [22]byte
|
|
}
|
|
|
|
copy(ifr.name[:], name)
|
|
ifr.flags = flags
|
|
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), syscall.TUNSETIFF, uintptr(unsafe.Pointer(&ifr)))
|
|
if errno != 0 {
|
|
syscall.Close(fd)
|
|
return -1, errno
|
|
}
|
|
|
|
if err = syscall.SetNonblock(fd, true); err != nil {
|
|
syscall.Close(fd)
|
|
return -1, err
|
|
}
|
|
|
|
return fd, nil
|
|
}
|