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/libnetdevice/common.cpp b/automotive/can/1.0/default/libnetdevice/common.cpp
new file mode 100644
index 0000000..3deac3e
--- /dev/null
+++ b/automotive/can/1.0/default/libnetdevice/common.cpp
@@ -0,0 +1,38 @@
+/*
+ * 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.
+ */
+
+#include "common.h"
+
+#include <android-base/logging.h>
+
+#include <net/if.h>
+
+namespace android {
+namespace netdevice {
+
+unsigned int nametoindex(const std::string& ifname) {
+    const auto ifidx = if_nametoindex(ifname.c_str());
+    if (ifidx != 0) return ifidx;
+
+    const auto err = errno;
+    if (err != ENODEV) {
+        LOG(ERROR) << "if_nametoindex(" << ifname << ") failed: " << err;
+    }
+    return 0;
+}
+
+}  // namespace netdevice
+}  // namespace android