allow listener retry listen (#554)

easytier/src/common/config.rs

@@ -27,7 +27,7 @@ pub fn gen_default_flags() -> Flags {
         relay_all_peer_rpc: false,
         disable_udp_hole_punching: false,
         ipv6_listener: "udp://[::]:0".to_string(),
-        multi_thread: false,
+        multi_thread: true,
         data_compress_algo: CompressionAlgoPb::None.into(),
     }
 }

easytier/src/common/global_ctx.rs

@@ -230,7 +230,10 @@ impl GlobalCtx {
     }
 
     pub fn add_running_listener(&self, url: url::Url) {
-        self.running_listeners.lock().unwrap().push(url);
+        let mut l = self.running_listeners.lock().unwrap();
+        if !l.contains(&url) {
+            l.push(url);
+        }
     }
 
     pub fn get_vpn_portal_cidr(&self) -> Option<cidr::Ipv4Cidr> {