initial commit

if.go

@@ -0,0 +1,71 @@
+package water
+
+import (
+	"os"
+)
+
+// Interface is a TUN/TAP interface.
+type Interface struct {
+	isTAP bool
+	file  *os.File
+	name  string
+}
+
+// Create a new TAP interface whose name is ifName.
+// If ifName is empty, a default name (tap0, tap1, ... ) will be assigned.
+// ifName should not exceed 16 bytes.
+func NewTAP(ifName string) (ifce *Interface, err error) {
+	file, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	name, err := createInterface(file.Fd(), ifName, cIFF_TAP|cIFF_NO_PI)
+	if err != nil {
+		return nil, err
+	}
+	ifce = &Interface{isTAP: true, file: file, name: name}
+	return
+}
+
+// Create a new TUN interface whose name is ifName.
+// If ifName is empty, a default name (tap0, tap1, ... ) will be assigned.
+// ifName should not exceed 16 bytes.
+func NewTUN(ifName string) (ifce *Interface, err error) {
+	file, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+	name, err := createInterface(file.Fd(), ifName, cIFF_TUN|cIFF_NO_PI)
+	if err != nil {
+		return nil, err
+	}
+	ifce = &Interface{isTAP: false, file: file, name: name}
+	return
+}
+
+// Returns true if ifce is a TUN interface, otherwise returns false;
+func (ifce *Interface) IsTUN() bool {
+	return !ifce.isTAP
+}
+
+// Returns true if ifce is a TAP interface, otherwise returns false;
+func (ifce *Interface) IsTAP() bool {
+	return ifce.isTAP
+}
+
+// Returns the interface name of ifce, e.g. tun0, tap1, etc..
+func (ifce *Interface) Name() string {
+	return ifce.name
+}
+
+// Implement io.Writer interface.
+func (ifce *Interface) Write(p []byte) (n int, err error) {
+	n, err = ifce.file.Write(p)
+	return
+}
+
+// Implement io.Reader interface.
+func (ifce *Interface) Read(p []byte) (n int, err error) {
+	n, err = ifce.file.Read(p)
+	return
+}