Merge "Define MacAddress class" am: 925349ac8f am: 37caaaa705

am: 3a818a0049

Change-Id: I0e09e64bb2a6306c0422443038351fabf10e2d6e

core/java/android/net/MacAddress.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2017 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.
+ */
+
+package android.net;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.util.Arrays;
+
+/**
+ * @hide
+ */
+public final class MacAddress {
+
+    // TODO: add isLocallyAssigned().
+    // TODO: add getRandomAddress() factory method.
+
+    private static final int ETHER_ADDR_LEN = 6;
+    private static final byte FF = (byte) 0xff;
+    @VisibleForTesting
+    static final byte[] ETHER_ADDR_BROADCAST = { FF, FF, FF, FF, FF, FF };
+
+    public enum MacAddressType {
+        UNICAST,
+        MULTICAST,
+        BROADCAST;
+    }
+
+    /** Return true if the given byte array is not null and has the length of a mac address. */
+    public static boolean isMacAddress(byte[] addr) {
+        return addr != null && addr.length == ETHER_ADDR_LEN;
+    }
+
+    /**
+     * Return the MacAddressType of the mac address represented by the given byte array,
+     * or null if the given byte array does not represent an mac address. */
+    public static MacAddressType macAddressType(byte[] addr) {
+        if (!isMacAddress(addr)) {
+            return null;
+        }
+        if (Arrays.equals(addr, ETHER_ADDR_BROADCAST)) {
+            return MacAddressType.BROADCAST;
+        }
+        if ((addr[0] & 0x01) == 1) {
+            return MacAddressType.MULTICAST;
+        }
+        return MacAddressType.UNICAST;
+    }
+}