Add ConfigureDialer

Author: nekohasekai

tsnet/tsnet.go

@@ -121,6 +121,8 @@ type Server struct {
 	// field at zero unless you know what you are doing.
 	Port uint16
 
+	ConfigureDialer func(dialer *tsdial.Dialer)
+
 	getCertForTesting func(*tls.ClientHelloInfo) (*tls.Certificate, error)
 
 	initOnce         sync.Once
@@ -530,6 +532,9 @@ func (s *Server) start() (reterr error) {
 	closePool.add(s.netMon)
 
 	s.dialer = &tsdial.Dialer{Logf: tsLogf} // mutated below (before used)
+	if s.ConfigureDialer != nil {
+		s.ConfigureDialer(s.dialer)
+	}
 	eng, err := wgengine.NewUserspaceEngine(tsLogf, wgengine.Config{
 		ListenPort:    s.Port,
 		NetMon:        s.netMon,