1 files changed, 32 insertions, 0 deletions
diff --git a/pkg/flipcall/flipcall.go b/pkg/flipcall/flipcall.go
new file mode 100644
index 000000000..79a1e418a
--- /dev/null
+++ b/pkg/flipcall/flipcall.go
@@ -0,0 +1,32 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package flipcall implements a protocol providing Fast Local Interprocess
+// Procedure Calls.
+package flipcall
+
+// ControlMode defines how control is exchanged across a connection.
+type ControlMode uint8
+
+const (
+	// ControlModeInvalid is invalid, and exists so that ControlMode fields in
+	// structs must be explicitly initialized.
+	ControlModeInvalid ControlMode = iota
+
+	// ControlModeFutex uses shared futex operations on packet control words.
+	ControlModeFutex
+
+	// controlModeCount is the number of ControlModes in this list.
+	controlModeCount
+)