add dummy functions for other platforms

src/yggdrasil/tcp.go

@@ -299,7 +299,7 @@ func (t *tcp) call(saddr string, options interface{}, sintf string, upgrade *Tcp
 				Timeout: time.Second * 5,
 			}
 			if sintf != "" {
-				dialer.Control = t.getContextWithBindToDevice(sintf)
+				dialer.Control = t.getControl(sintf)
 				ief, err := net.InterfaceByName(sintf)
 				if err != nil {
 					return

src/yggdrasil/tcp_darwin.go

@@ -26,3 +26,7 @@ func (t *tcp) tcpContext(network, address string, c syscall.RawConn) error {
 		return control
 	}
 }
+
+func (t *tcp) getControl(sintf string) func(string, string, syscall.RawConn) error {
+	return t.tcpContext
+}

src/yggdrasil/tcp_linux.go

@@ -30,7 +30,7 @@ func (t *tcp) tcpContext(network, address string, c syscall.RawConn) error {
 	return nil
 }
 
-func (t *tcp) getContextWithBindToDevice(sintf string) func(string, string, syscall.RawConn) error {
+func (t *tcp) getControl(sintf string) func(string, string, syscall.RawConn) error {
 	return func(network, address string, c syscall.RawConn) error {
 		var err error
 		btd := func(fd uintptr) {

src/yggdrasil/tcp_other.go

@@ -11,3 +11,7 @@ import (
 func (t *tcp) tcpContext(network, address string, c syscall.RawConn) error {
 	return nil
 }
+
+func (t *tcp) getControl(sintf string) func(string, string, syscall.RawConn) error {
+	return t.tcpContext
+}