revamp command line parser

1 files changed, 21 insertions, 0 deletions

diff --git a/tuntap/tuntap.go b/tuntap/tuntap.go
index 3dde53b..27fd2b1 100644
--- a/tuntap/tuntap.go
+++ b/tuntap/tuntap.go
@@ -32,6 +32,7 @@ package tuntap
 
 import (
 	"fmt"
+	"strings"
 
 	extlib "github.com/lab11/go-tuntap/tuntap"
 )
@@ -78,3 +79,23 @@ func NewTapDevice(name string) (dev *Device, err error) {
 	}
 	return
 }
+
+func NewDevice(iftype, name string) (dev *Device, err error) {
+	if iftype == "" {
+		if strings.HasPrefix(name, "tun") {
+			return NewTunDevice(name)
+		}
+		if strings.HasPrefix(name, "tap") {
+			return NewTapDevice(name)
+		}
+		return nil, fmt.Errorf("no device type is set and the given interface name(%s) doesn't start with 'tun' or 'tap'", name)
+	}
+
+	switch strings.ToLower(iftype) {
+	case "tun":
+		return NewTunDevice(name)
+	case "tap":
+		return NewTapDevice(name)
+	}
+	return nil, fmt.Errorf("invalid interface type: %s", iftype)
+}