api: add ring management

Rather than every client reinvent the art of using the Wintun and its
ring buffers, we offer helper structs and functions to unify and
simplify Wintun usage.

Signed-off-by: Simon Rozman <simon@rozman.si>

1 files changed, 26 insertions, 0 deletions

diff --git a/api/atomic.h b/api/atomic.h
new file mode 100644
index 0000000..011e53b
--- /dev/null
+++ b/api/atomic.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2018-2020 WireGuard LLC. All Rights Reserved.
+ */
+
+#pragma once
+
+#include <Windows.h>
+
+static __forceinline VOID
+InterlockedSetU(_Inout_ _Interlocked_operand_ ULONG volatile *Target, _In_ ULONG Value)
+{
+    *Target = Value;
+}
+
+static __forceinline LONG
+InterlockedGet(_In_ _Interlocked_operand_ LONG volatile *Value)
+{
+    return *Value;
+}
+
+static __forceinline ULONG
+InterlockedGetU(_In_ _Interlocked_operand_ ULONG volatile *Value)
+{
+    return *Value;
+}