Fixed a few network UI issues in swarm-mode

* Detect name conflicts on network creation
* Detect and prevent network connect/disconnect for managed containers

Signed-off-by: Madhu Venugopal <madhu@docker.com>

api/server/router/network/network_routes.go

@@ -81,6 +81,10 @@ func (n *networkRouter) postNetworkCreate(ctx context.Context, w http.ResponseWr
 		return err
 	}
 
+	if _, err := n.clusterProvider.GetNetwork(create.Name); err == nil {
+		return libnetwork.NetworkNameError(create.Name)
+	}
+
 	nw, err := n.backend.CreateNetwork(create)
 	if err != nil {
 		if _, ok := err.(libnetwork.ManagerRedirectError); !ok {

daemon/network.go

@@ -292,6 +292,10 @@ func (daemon *Daemon) UpdateContainerServiceConfig(containerName string, service
 	return nil
 }
 
+func errClusterNetworkConnect() error {
+	return fmt.Errorf("cannot connect or disconnect managed containers on a network")
+}
+
 // ConnectContainerToNetwork connects the given container to the given
 // network. If either cannot be found, an err is returned. If the
 // network cannot be set up, an err is returned.
@@ -300,6 +304,9 @@ func (daemon *Daemon) ConnectContainerToNetwork(containerName, networkName strin
 	if err != nil {
 		return err
 	}
+	if container.Managed {
+		return errClusterNetworkConnect()
+	}
 	return daemon.ConnectToNetwork(container, networkName, endpointConfig)
 }
 
@@ -313,6 +320,9 @@ func (daemon *Daemon) DisconnectContainerFromNetwork(containerName string, netwo
 		}
 		return err
 	}
+	if container.Managed {
+		return errClusterNetworkConnect()
+	}
 	return daemon.DisconnectFromNetwork(container, network, force)
 }