Address comments.

Signed-off-by: John Plevyak <jplevyak@gmail.com>

include/proxy-wasm/network_interface.h

@@ -0,0 +1,95 @@
+// Copyright 2016-2019 Envoy Project Authors
+// Copyright 2020 Google LLC
+//
+// 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.
+
+#pragma once
+
+#include "include/proxy-wasm/compat.h"
+
+#include <time.h>
+#include <atomic>
+#include <chrono>
+#include <functional>
+#include <iostream>
+#include <map>
+#include <memory>
+#include <vector>
+
+#include "include/proxy-wasm/proxy_action.h"
+
+namespace proxy_wasm {
+
+/**
+ * NetworkInterface is the interface between the VM host and the VM for network streams.
+ */
+class NetworkInterface {
+public:
+  /**
+   * Network
+   * Note: Body data is obtained by the code in the VM via calls implemented by the
+   * proxy-independent host code using the getBuffer() call.
+   */
+
+  /**
+   * Call on a stream Context to indicate that a new network connection has been been created.
+   * Calls onStart().
+   */
+  virtual ProxyAction onNetworkNewConnection() = 0;
+
+  /**
+   * Call on a stream Context to indicate that data has arrived from downstream (e.g. on the
+   * incoming port that was accepted and for which the proxy is acting as a server).
+   * @param data_length the amount of data in the buffer.
+   * @param end_of_stream is true if no more data will be arriving.
+   * @return indicates the subsequent behavior of this stream, e.g. continue proxying or pause
+   * proxying.
+   */
+  virtual ProxyAction onDownstreamData(uint32_t data_length, bool end_of_stream) = 0;
+
+  /**
+   * Call on a stream Context to indicate that data has arrived from upstream (e.g. on the outgoing
+   * port that the proxy connected and for which the proxy is acting as a client).
+   * @param data_length the amount of data in the buffer.
+   * @param end_of_stream is true if no more data will be arriving.
+   * @return indicates the subsequent behavior of this stream, e.g. continue proxying or pause
+   * proxying.
+   */
+  virtual ProxyAction onUpstreamData(uint32_t data_length, bool end_of_stream) = 0;
+
+  /*
+   * The source of the close event.
+   * Unknown is when the source is not known.
+   * Local is when the close was initiated by the proxy.
+   * Remote is when the close was received from the peer.
+   */
+  enum class CloseType : uint32_t {
+    Unknown = 0,
+    Local = 1,
+    Remote = 2,
+  };
+
+  /**
+   * Call on a stream context to indicate that the downstream connection has closed.
+   * @close_type is the source of the close.
+   */
+  virtual void onDownstreamConnectionClose(CloseType close_type) = 0;
+
+  /**
+   * Call on a stream context to indicate that the upstream connection has closed.
+   * @close_type is the source of the close.
+   */
+  virtual void onUpstreamConnectionClose(CloseType close_type) = 0;
+};
+
+} // namespace proxy_wasm