Default implementation for CAN bus HAL

This implementation supports SocketCAN interfaces.

Bug: 135918744
Test: VTS (separate new change)
Change-Id: I12b93e37fa64e341bee2c64eaf130b39977fcef5
diff --git a/automotive/can/1.0/default/CanSocket.h b/automotive/can/1.0/default/CanSocket.h
new file mode 100644
index 0000000..cd7162d
--- /dev/null
+++ b/automotive/can/1.0/default/CanSocket.h
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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 <android-base/macros.h>
+#include <android-base/unique_fd.h>
+#include <linux/can.h>
+
+#include <atomic>
+#include <chrono>
+#include <thread>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace can {
+namespace V1_0 {
+namespace implementation {
+
+/**
+ * Wrapper around SocketCAN socket.
+ */
+struct CanSocket {
+    using ReadCallback = std::function<void(const struct canfd_frame&, std::chrono::nanoseconds)>;
+    using ErrorCallback = std::function<void()>;
+
+    /**
+     * Open and bind SocketCAN socket.
+     *
+     * \param ifname SocketCAN network interface name (such as can0)
+     * \param rdcb Callback on received messages
+     * \param errcb Callback on socket failure
+     * \return Socket instance, or nullptr if it wasn't possible to open one
+     */
+    static std::unique_ptr<CanSocket> open(const std::string& ifname, ReadCallback rdcb,
+                                           ErrorCallback errcb);
+    virtual ~CanSocket();
+
+    /**
+     * Send CAN frame.
+     *
+     * \param frame Frame to send
+     * \return true in case of success, false otherwise
+     */
+    bool send(const struct canfd_frame& frame);
+
+  private:
+    CanSocket(base::unique_fd socket, ReadCallback rdcb, ErrorCallback errcb);
+    void readerThread();
+
+    ReadCallback mReadCallback;
+    ErrorCallback mErrorCallback;
+
+    const base::unique_fd mSocket;
+    std::thread mReaderThread;
+    std::atomic<bool> mStopReaderThread = false;
+
+    DISALLOW_COPY_AND_ASSIGN(CanSocket);
+};
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace can
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android