[Feature]: Add Get/Set MAC addresses

README.md

@@ -51,6 +51,15 @@ func main() {
  if err != nil {
  log.Fatal(err)
  }
+
+ ifce.SetMAC("d6:db:b0:42:2c:7e")
+
+ mac, err := ifce.GetMAC()
+ if err != nil {
+ log.Fatal(err)
+ }
+ fmt.Println("MAC address:", mac)
+
  var frame ethernet.Frame
 
  for {

if.go

@@ -3,6 +3,10 @@ package water
 import (
  "errors"
  "io"
+ "net"
+ "os"
+ "syscall"
+ "unsafe"
 )
 
 // Interface is a TUN/TAP interface.
@@ -78,3 +82,57 @@ func (ifce *Interface) IsTAP() bool {
 func (ifce *Interface) Name() string {
  return ifce.name
 }
+
+// GetMAC returns the created interface's MAC address
+func (ifce *Interface) GetMAC() (string, error) {
+ var req ifReq
+ req.Flags = syscall.AF_UNIX
+ copy(req.Name[:], ifce.name)
+
+ fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
+ if err != nil {
+ return "", os.NewSyscallError("socket", err)
+ }
+ defer syscall.Close(fd)
+
+ err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
+ if err != nil {
+ return "", os.NewSyscallError("setsockopt", err)
+ }
+
+ err = ioctl(uintptr(fd), syscall.SIOCGIFHWADDR, uintptr(unsafe.Pointer(&req)))
+ if err != nil {
+ return "", err
+ }
+ return net.HardwareAddr(req.Mac[:]).String(), nil
+}
+
+// SetMAC sets the MAC address for the interface
+func (ifce *Interface) SetMAC(mac string) error {
+ var req ifReq
+ req.Flags = syscall.AF_UNIX
+ copy(req.Name[:], ifce.name)
+
+ macBytes, err := net.ParseMAC(mac)
+ if err != nil {
+ return err
+ }
+ copy(req.Mac[:], macBytes)
+
+ fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, 0)
+ if err != nil {
+ return os.NewSyscallError("socket", err)
+ }
+ defer syscall.Close(fd)
+
+ err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
+ if err != nil {
+ return os.NewSyscallError("setsockopt", err)
+ }
+
+ err = ioctl(uintptr(fd), syscall.SIOCSIFHWADDR, uintptr(unsafe.Pointer(&req)))
+ if err != nil {
+ return err
+ }
+ return nil
+}

syscalls_linux.go

@@ -17,7 +17,8 @@ const (
 type ifReq struct {
  Name [0x10]byte
  Flags uint16
- pad [0x28 - 0x10 - 2]byte
+ Mac [6]byte
+ pad [0x28 - 0x10 - 8]byte
 }
 
 func ioctl(fd uintptr, request uintptr, argp uintptr) error {