allow us to check additional networks on native when the default is used

util/provider/native.go

@@ -122,12 +122,65 @@ func (native Native) Start() error {
 	if !native.hasNetwork() {
 		display.StartTask("Setting up custom docker network...")
 
-		config, _ := models.LoadConfig()
+		config, err := models.LoadConfig()
+		if err != nil {
+			return err
+		}
+
+		// if we are using the default network configuration 
+		// then we are free to try getting one that works without confirming with the user any changes
+		if config.NativeNetworkSpace == "172.20.0.1/16" {
+			// create the values we will need outside the loop
+			var oct int
+			var newNetSpace string			
+
+			for i := 0; i < 10; i++ {
+				// get the value of the 2nd octet and use I to increment it
+				// to allow different networks to be used
+				fmt.Sscanf(config.NativeNetworkSpace, "172.%d.0.1/16", &oct)
+				newNetSpace = fmt.Sprintf("172.%d.0.1/16", oct + i)
+
+				ip, ipNet, err := net.ParseCIDR(newNetSpace)
+				if err != nil {
+					return err
+				}
+
+				cmd := exec.Command("docker", "network", "create", "--driver=bridge", fmt.Sprintf("--subnet=%s", ipNet.String()), "--opt=\"com.docker.network.driver.mtu=1450\"", "--opt=\"com.docker.network.bridge.name=redd0\"", fmt.Sprintf("--gateway=%s", ip.String()), "nanobox")
+
+				cmd.Stdout = display.NewStreamer("  ")
+				cmd.Stderr = display.NewStreamer("  ")
+
+				err = cmd.Run()
+
+				if err == nil {
+					break
+				}
+			}
+
+			// if we did all the loops and still have an error. we need to report it
+			if err != nil {
+				display.ErrorTask()
+				display.NetworkCreateError("native-network-space", config.NativeNetworkSpace)
+				return err	
+			}
+
+			// with no errors we will return here
+			if newNetSpace != config.NativeNetworkSpace {
+				config.NativeNetworkSpace = newNetSpace
+				config.Save()				
+			}
+
+			display.StopTask()
+			return nil
+
+		}
+
 		ip, ipNet, err := net.ParseCIDR(config.NativeNetworkSpace)
 		if err != nil {
 			return err
 		}
 
+
 		cmd := exec.Command("docker", "network", "create", "--driver=bridge", fmt.Sprintf("--subnet=%s", ipNet.String()), "--opt=\"com.docker.network.driver.mtu=1450\"", "--opt=\"com.docker.network.bridge.name=redd0\"", fmt.Sprintf("--gateway=%s", ip.String()), "nanobox")
 
 		cmd.Stdout = display.NewStreamer("  ")