Files
netstack/tcpip/link/tuntap/tuntap.go
impact-eintr ff4cde9809 tuntap test
2022-11-22 15:04:29 +08:00

139 lines
2.8 KiB
Go

package tuntap
import (
"errors"
"fmt"
"os/exec"
"syscall"
"unsafe"
)
const (
TUN = 1
TAP = 2
)
var (
ErrDeviceMode = errors.New("unsupport device mode")
)
type rawSockaddr struct {
Family uint16
Data [14]byte
}
type Config struct {
Name string // 网卡名
Mode int // 网卡模式 TUN or TAP
}
// NewNetDev根据配置返回虚拟网卡的文件描述符
func NewNetDev(c *Config) (fd int, err error) {
switch c.Mode {
case TUN:
fd, err = newTun(c.Name)
case TAP:
fd, err = newTap(c.Name)
default:
err = ErrDeviceMode
return
}
if err != nil {
return
}
return
}
// TUN 工作在第二层
func newTun(name string) (int, error) {
return open(name, syscall.IFF_TUN|syscall.IFF_NO_PI)
}
// TAP工作在第三层
func newTap(name string) (int, error){
return open(name, syscall.IFF_TAP|syscall.IFF_NO_PI)
}
func open(name string, flags uint16) (int, error) {
// 打开tuntap 设备
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
// 通过ioctl系统调用 将fd和虚拟网卡驱动绑定在一起
_, _ , errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd),
syscall.TUNSETIFF, uintptr(unsafe.Pointer(&ifr)))
if errno != 0 {
syscall.Close(fd)
return -1, errno
}
return fd, nil
}
// SetLinkUp 让系统启动该网卡 ip link set tap0 up
func SetLinkUp(name string) (err error) {
// ip link set <device-name> up
out, cmdErr := exec.Command("ip", "link", "set", name, "up").CombinedOutput()
if cmdErr != nil {
err = fmt.Errorf("%v:%v", cmdErr, string(out))
return
}
return
}
// SetRoute 通过ip命令添加路由
func SetRoute(name, cidr string) (err error) {
// ip route add 192.168.1.0/24 dev tap0
out, cmdErr := exec.Command("ip", "route", "add", cidr, "dev", name).CombinedOutput()
if cmdErr != nil {
err = fmt.Errorf("%v:%v", cmdErr, string(out))
return
}
return
}
// AddIP 通过ip命令添加IP地址
func AddIP(name, ip string) (err error) {
// ip addr add 192.168.1.1 dev tap0
out, cmdErr := exec.Command("ip", "addr", "add", ip, "dev", name).CombinedOutput()
if cmdErr != nil {
err = fmt.Errorf("%v:%v",cmdErr, string(out))
return
}
return
}
func GetHardwareAddr(name string) (string, error) {
fd, err := syscall.Socket(syscall.AF_UNIX, syscall.SOCK_DGRAM, 0) // 新建socket文件
if err != nil {
return "", nil
}
defer syscall.Close(fd)
var ifreq struct {
name [16]byte
addr rawSockaddr
_ [8]byte
}
copy(ifreq.name[:], name)
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), syscall.SIOCGIFHWADDR,
uintptr(unsafe.Pointer(&ifreq))) // 获取硬件地址
if errno != 0 {
return "", errno
}
mac := ifreq.addr.Data[:6]
return string(mac[:]), nil
}