TUN-7480: Added a timeout for unregisterUDP.

I deliberately kept this as an unregistertimeout because that was the
intent. In the future we could change this to a UDPConnConfig if we want
to pass multiple values here.

The idea of this PR is simply to add a configurable unregister UDP
timeout.

quic/quic_protocol_test.go

@@ -109,6 +109,63 @@ func TestConnectResponseMeta(t *testing.T) {
 	}
 }
 
+func TestUnregisterUdpSession(t *testing.T) {
+	unregisterMessage := "closed by eyeball"
+
+	var tests = []struct {
+		name             string
+		sessionRPCServer mockSessionRPCServer
+		timeout          time.Duration
+	}{
+
+		{
+			name: "UnregisterUdpSessionTimesout if the RPC server does not respond",
+			sessionRPCServer: mockSessionRPCServer{
+				sessionID:         uuid.New(),
+				dstIP:             net.IP{172, 16, 0, 1},
+				dstPort:           8000,
+				closeIdleAfter:    testCloseIdleAfterHint,
+				unregisterMessage: unregisterMessage,
+				traceContext:      "1241ce3ecdefc68854e8514e69ba42ca:b38f1bf5eae406f3:0:1",
+			},
+			// very very low value so we trigger the timeout every time.
+			timeout: time.Nanosecond * 1,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			logger := zerolog.Nop()
+			clientStream, serverStream := newMockRPCStreams()
+			sessionRegisteredChan := make(chan struct{})
+			go func() {
+				protocol, err := DetermineProtocol(serverStream)
+				assert.NoError(t, err)
+				rpcServerStream, err := NewRPCServerStream(serverStream, protocol)
+				assert.NoError(t, err)
+				err = rpcServerStream.Serve(test.sessionRPCServer, nil, &logger)
+				assert.NoError(t, err)
+
+				serverStream.Close()
+				close(sessionRegisteredChan)
+			}()
+
+			rpcClientStream, err := NewRPCClientStream(context.Background(), clientStream, test.timeout, &logger)
+			assert.NoError(t, err)
+
+			reg, err := rpcClientStream.RegisterUdpSession(context.Background(), test.sessionRPCServer.sessionID, test.sessionRPCServer.dstIP, test.sessionRPCServer.dstPort, testCloseIdleAfterHint, test.sessionRPCServer.traceContext)
+			assert.NoError(t, err)
+			assert.NoError(t, reg.Err)
+
+			assert.Error(t, rpcClientStream.UnregisterUdpSession(context.Background(), test.sessionRPCServer.sessionID, unregisterMessage))
+
+			rpcClientStream.Close()
+			<-sessionRegisteredChan
+		})
+	}
+
+}
+
 func TestRegisterUdpSession(t *testing.T) {
 	unregisterMessage := "closed by eyeball"
 
@@ -157,7 +214,7 @@ func TestRegisterUdpSession(t *testing.T) {
 				close(sessionRegisteredChan)
 			}()
 
-			rpcClientStream, err := NewRPCClientStream(context.Background(), clientStream, &logger)
+			rpcClientStream, err := NewRPCClientStream(context.Background(), clientStream, 5*time.Second, &logger)
 			assert.NoError(t, err)
 
 			reg, err := rpcClientStream.RegisterUdpSession(context.Background(), test.sessionRPCServer.sessionID, test.sessionRPCServer.dstIP, test.sessionRPCServer.dstPort, testCloseIdleAfterHint, test.sessionRPCServer.traceContext)
@@ -208,7 +265,7 @@ func TestManageConfiguration(t *testing.T) {
 
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
-	rpcClientStream, err := NewRPCClientStream(ctx, clientStream, &logger)
+	rpcClientStream, err := NewRPCClientStream(ctx, clientStream, 5*time.Second, &logger)
 	assert.NoError(t, err)
 
 	result, err := rpcClientStream.UpdateConfiguration(ctx, version, config)