Restore original tun.go code

tun/tun.go

@@ -4,8 +4,10 @@
 package tun
 
 import (
+	"fmt"
+	"os/exec"
+
 	"github.com/songgao/water"
-	"github.com/vishvananda/netlink"
 )
 
 // New creates and returns a new TUN interface for the application.
@@ -22,50 +24,32 @@ func New(name string, address string) (result *water.Interface, err error) {
 
 // SetMTU sets the Maximum Tansmission Unit Size for a
 // Packet on the interface.
-func SetMTU(name string, mtu int) error {
-	link, err := netlink.LinkByName(name)
-	if err != nil {
-		return err
-	}
-	return netlink.LinkSetMTU(link, mtu)
+func SetMTU(name string, mtu int) (err error) {
+	return ip("link", "set", "dev", name, "mtu", fmt.Sprintf("%d", mtu))
 }
 
 // SetAddress sets the interface's known address and subnet.
-func SetAddress(name string, address string) error {
-	addr, err := netlink.ParseAddr(address)
-	if err != nil {
-		return err
-	}
-	link, err := netlink.LinkByName(name)
-	if err != nil {
-		return err
-	}
-	return netlink.AddrAdd(link, addr)
+func SetAddress(name string, address string) (err error) {
+	return ip("addr", "add", address, "dev", name)
 }
 
 // Up brings up an interface to allow it to start accepting connections.
-func Up(name string) error {
-	link, err := netlink.LinkByName(name)
-	if err != nil {
-		return err
-	}
-	return netlink.LinkSetUp(link)
+func Up(name string) (err error) {
+	return ip("link", "set", "dev", name, "up")
 }
 
 // Down brings down an interface stopping active connections.
-func Down(name string) error {
-	link, err := netlink.LinkByName(name)
-	if err != nil {
-		return err
-	}
-	return netlink.LinkSetDown(link)
+func Down(name string) (err error) {
+	return ip("link", "set", "dev", name, "down")
 }
 
 // Delete removes a TUN device from the host.
-func Delete(name string) error {
-	link, err := netlink.LinkByName(name)
-	if err != nil {
-		return err
-	}
-	return netlink.LinkDel(link)
+func Delete(name string) (err error) {
+	return ip("link", "delete", "dev", name)
+}
+
+func ip(args ...string) (err error) {
+	cmd := exec.Command("ip", args...)
+	err = cmd.Run()
+	return
 }

tun/tun_linux.go

@@ -0,0 +1,71 @@
+//go:build linux
+// +build linux
+
+package tun
+
+import (
+	"github.com/songgao/water"
+	"github.com/vishvananda/netlink"
+)
+
+// New creates and returns a new TUN interface for the application.
+func New(name string) (result *water.Interface, err error) {
+	// Setup TUN Config
+	cfg := water.Config{
+		DeviceType: water.TUN,
+	}
+	cfg.Name = name
+	// Create TUN Interface
+	result, err = water.New(cfg)
+	return
+}
+
+// SetMTU sets the Maximum Tansmission Unit Size for a
+// Packet on the interface.
+func SetMTU(name string, mtu int) error {
+	link, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+	return netlink.LinkSetMTU(link, mtu)
+}
+
+// SetAddress sets the interface's known address and subnet.
+func SetAddress(name string, address string) error {
+	addr, err := netlink.ParseAddr(address)
+	if err != nil {
+		return err
+	}
+	link, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+	return netlink.AddrAdd(link, addr)
+}
+
+// Up brings up an interface to allow it to start accepting connections.
+func Up(name string) error {
+	link, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+	return netlink.LinkSetUp(link)
+}
+
+// Down brings down an interface stopping active connections.
+func Down(name string) error {
+	link, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+	return netlink.LinkSetDown(link)
+}
+
+// Delete removes a TUN device from the host.
+func Delete(name string) error {
+	link, err := netlink.LinkByName(name)
+	if err != nil {
+		return err
+	}
+	return netlink.LinkDel(link)
+}