Merge fbe99b5 into e4937f5

.travis.yml

@@ -16,9 +16,12 @@ before_script:
   - chmod +x ./cc-test-reporter
   - ./cc-test-reporter before-build
   - GO111MODULE=off go get github.com/mattn/goveralls
+  - export GO_EXECUTABLE_PATH=$(which go)
+  - sudo -E setcap cap_net_admin+ep $GO_EXECUTABLE_PATH
 script:
   # HACK: /dev/kvm is root:kvm 0660 by default
   - sudo chmod 666 /dev/kvm
+  - sudo chmod 666 /dev/net/tun
   - make gokvm
   - make test
   - goveralls -service=travis-ci -coverprofile c.out

tap/tap.go

@@ -0,0 +1,65 @@
+package tap
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const ifNameSize = 0x10
+
+type Tap struct {
+	fd int
+}
+
+type ifReq struct {
+	Name  [ifNameSize]byte
+	Flags uint16
+	_     [0x28 - ifNameSize - 2]byte
+}
+
+func ioctl(fd, op, arg uintptr) (uintptr, error) {
+	res, _, errno := syscall.Syscall(
+		syscall.SYS_IOCTL, fd, op, arg)
+
+	var err error = nil
+	if errno != 0 {
+		err = errno
+	}
+
+	return res, err
+}
+
+func New(name string) (*Tap, error) {
+	var err error
+
+	t := &Tap{}
+
+	if t.fd, err = syscall.Open("/dev/net/tun", syscall.O_RDWR, 0); err != nil {
+		return t, err
+	}
+
+	ifr := ifReq{
+		Name:  [ifNameSize]byte{},
+		Flags: syscall.IFF_TAP | syscall.IFF_NO_PI,
+	}
+	copy(ifr.Name[:ifNameSize-1], name)
+
+	ifrPtr := uintptr(unsafe.Pointer(&ifr))
+	if _, err = ioctl(uintptr(t.fd), syscall.TUNSETIFF, ifrPtr); err != nil {
+		return t, err
+	}
+
+	return t, nil
+}
+
+func (t *Tap) Close() error {
+	return syscall.Close(t.fd)
+}
+
+func (t Tap) Tx(bytes []byte) error {
+	if _, err := syscall.Write(t.fd, bytes); err != nil {
+		return err
+	}
+
+	return nil
+}

tap/tap_test.go

@@ -0,0 +1,21 @@
+package tap_test
+
+import (
+	"testing"
+
+	"github.com/bobuhiro11/gokvm/tap"
+)
+
+func TestNew(t *testing.T) {
+	t.Parallel()
+
+	tap, err := tap.New("test_tap")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = tap.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+}