Add a queue for sending order

kylecarbs · kylecarbs · commit cbede6cb85fd · 2022-09-08T02:38:16.000Z
diff --git a/tailnet/conn.go b/tailnet/conn.go
@@ -248,6 +248,18 @@ func (c *Conn) SetForwardTCPCallback(callback func(conn net.Conn, listenerExists
 // renegotiation may be required. Clients should constantly be emitting
 // node changes.
 func (c *Conn) SetNodeCallback(callback func(node *Node)) {
+	queue := make(chan *Node, 16)
+	go func() {
+		defer close(queue)
+		for {
+			select {
+			case <-c.closed:
+				return
+			case node := <-queue:
+				callback(node)
+			}
+		}
+	}()
 	makeNode := func() *Node {
 		return &Node{
 			ID:            c.netMap.SelfNode.ID,
@@ -265,8 +277,8 @@ func (c *Conn) SetNodeCallback(callback func(node *Node)) {
 		c.lastPreferredDERP = ni.PreferredDERP
 		c.lastDERPLatency = ni.DERPLatency
 		node := makeNode()
+		queue <- node
 		c.lastMutex.Unlock()
-		callback(node)
 	})
 	c.wireguardEngine.SetStatusCallback(func(s *wgengine.Status, err error) {
 		if err != nil {
@@ -276,13 +288,11 @@ func (c *Conn) SetNodeCallback(callback func(node *Node)) {
 		for _, addr := range s.LocalAddrs {
 			endpoints = append(endpoints, addr.Addr.String())
 		}
-		go func() {
-			c.lastMutex.Lock()
-			c.lastEndpoints = endpoints
-			node := makeNode()
-			c.lastMutex.Unlock()
-			callback(node)
-		}()
+		c.lastMutex.Lock()
+		c.lastEndpoints = endpoints
+		node := makeNode()
+		queue <- node
+		c.lastMutex.Unlock()
 	})
 }
 
