MacAddress follow-up: define the core of the class

Test: new unit test parts of $ runtest frameworks-net
Change-Id: I08c57d2d656802f7bdd7a93fde711a7e77247583

1 files changed, 226 insertions, 14 deletions

diff --git a/core/java/android/net/MacAddress.java b/core/java/android/net/MacAddress.java
index e76d17d0535b..f6a69bacb319 100644
--- a/core/java/android/net/MacAddress.java
+++ b/core/java/android/net/MacAddress.java
@@ -16,29 +16,128 @@
 
 package android.net;
 
-import com.android.internal.annotations.VisibleForTesting;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+import com.android.internal.util.BitUtils;
 
 import java.util.Arrays;
+import java.util.Random;
+import java.util.StringJoiner;
 
 /**
+ * Represents a mac address.
+ *
  * @hide
  */
-public final class MacAddress {
-
-    // TODO: add isLocallyAssigned().
-    // TODO: add getRandomAddress() factory method.
+public final class MacAddress implements Parcelable {
 
     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 };
+    private static final byte[] ETHER_ADDR_BROADCAST = addr(0xff, 0xff, 0xff, 0xff, 0xff, 0xff);
+
+    /** The broadcast mac address.  */
+    public static final MacAddress BROADCAST_ADDRESS = new MacAddress(ETHER_ADDR_BROADCAST);
+
+    /** The zero mac address. */
+    public static final MacAddress ALL_ZEROS_ADDRESS = new MacAddress(0);
 
+    /** Represents categories of mac addresses. */
     public enum MacAddressType {
         UNICAST,
         MULTICAST,
         BROADCAST;
     }
 
+    private static final long VALID_LONG_MASK = BROADCAST_ADDRESS.mAddr;
+    private static final long LOCALLY_ASSIGNED_MASK = new MacAddress("2:0:0:0:0:0").mAddr;
+    private static final long MULTICAST_MASK = new MacAddress("1:0:0:0:0:0").mAddr;
+    private static final long OUI_MASK = new MacAddress("ff:ff:ff:0:0:0").mAddr;
+    private static final long NIC_MASK = new MacAddress("0:0:0:ff:ff:ff").mAddr;
+    private static final MacAddress BASE_ANDROID_MAC = new MacAddress("da:a1:19:0:0:0");
+
+    // Internal representation of the mac address as a single 8 byte long.
+    // The encoding scheme sets the two most significant bytes to 0. The 6 bytes of the
+    // mac address are encoded in the 6 least significant bytes of the long, where the first
+    // byte of the array is mapped to the 3rd highest logical byte of the long, the second
+    // byte of the array is mapped to the 4th highest logical byte of the long, and so on.
+    private final long mAddr;
+
+    private MacAddress(long addr) {
+        mAddr = addr;
+    }
+
+    /** Creates a MacAddress for the given byte representation. */
+    public MacAddress(byte[] addr) {
+        this(longAddrFromByteAddr(addr));
+    }
+
+    /** Creates a MacAddress for the given string representation. */
+    public MacAddress(String addr) {
+        this(longAddrFromByteAddr(byteAddrFromStringAddr(addr)));
+    }
+
+    /** Returns the MacAddressType of this MacAddress. */
+    public MacAddressType addressType() {
+        if (equals(BROADCAST_ADDRESS)) {
+            return MacAddressType.BROADCAST;
+        }
+        if (isMulticastAddress()) {
+            return MacAddressType.MULTICAST;
+        }
+        return MacAddressType.UNICAST;
+    }
+
+    /** Returns true if this MacAddress corresponds to a multicast address. */
+    public boolean isMulticastAddress() {
+        return (mAddr & MULTICAST_MASK) != 0;
+    }
+
+    /** Returns true if this MacAddress corresponds to a locally assigned address. */
+    public boolean isLocallyAssigned() {
+        return (mAddr & LOCALLY_ASSIGNED_MASK) != 0;
+    }
+
+    /** Returns a byte array representation of this MacAddress. */
+    public byte[] toByteArray() {
+        return byteAddrFromLongAddr(mAddr);
+    }
+
+    @Override
+    public String toString() {
+        return stringAddrFromByteAddr(byteAddrFromLongAddr(mAddr));
+    }
+
+    @Override
+    public int hashCode() {
+        return (int) ((mAddr >> 32) ^ mAddr);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return (o instanceof MacAddress) && ((MacAddress) o).mAddr == mAddr;
+    }
+
+    @Override
+    public void writeToParcel(Parcel out, int flags) {
+        out.writeLong(mAddr);
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    public static final Parcelable.Creator<MacAddress> CREATOR =
+            new Parcelable.Creator<MacAddress>() {
+                public MacAddress createFromParcel(Parcel in) {
+                    return new MacAddress(in.readLong());
+                }
+
+                public MacAddress[] newArray(int size) {
+                    return new MacAddress[size];
+                }
+            };
+
     /** 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;
@@ -46,17 +145,130 @@ public final class MacAddress {
 
     /**
      * 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. */
+     * 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;
+        return new MacAddress(addr).addressType();
+    }
+
+    /** DOCME */
+    public static byte[] byteAddrFromStringAddr(String addr) {
+        if (addr == null) {
+            throw new IllegalArgumentException("cannot convert the null String");
         }
-        if ((addr[0] & 0x01) == 1) {
-            return MacAddressType.MULTICAST;
+        String[] parts = addr.split(":");
+        if (parts.length != ETHER_ADDR_LEN) {
+            throw new IllegalArgumentException(addr + " was not a valid MAC address");
         }
-        return MacAddressType.UNICAST;
+        byte[] bytes = new byte[ETHER_ADDR_LEN];
+        for (int i = 0; i < ETHER_ADDR_LEN; i++) {
+            int x = Integer.valueOf(parts[i], 16);
+            if (x < 0 || 0xff < x) {
+                throw new IllegalArgumentException(addr + "was not a valid MAC address");
+            }
+            bytes[i] = (byte) x;
+        }
+        return bytes;
+    }
+
+    /** DOCME */
+    public static String stringAddrFromByteAddr(byte[] addr) {
+        if (!isMacAddress(addr)) {
+            return null;
+        }
+        StringJoiner j = new StringJoiner(":");
+        for (byte b : addr) {
+            j.add(Integer.toHexString(BitUtils.uint8(b)));
+        }
+        return j.toString();
+    }
+
+    /** @hide */
+    public static byte[] byteAddrFromLongAddr(long addr) {
+        byte[] bytes = new byte[ETHER_ADDR_LEN];
+        int index = ETHER_ADDR_LEN;
+        while (index-- > 0) {
+            bytes[index] = (byte) addr;
+            addr = addr >> 8;
+        }
+        return bytes;
+    }
+
+    /** @hide */
+    public static long longAddrFromByteAddr(byte[] addr) {
+        if (!isMacAddress(addr)) {
+            throw new IllegalArgumentException(
+                    Arrays.toString(addr) + " was not a valid MAC address");
+        }
+        long longAddr = 0;
+        for (byte b : addr) {
+            longAddr = (longAddr << 8) + BitUtils.uint8(b);
+        }
+        return longAddr;
+    }
+
+    /** @hide */
+    public static long longAddrFromStringAddr(String addr) {
+        if (addr == null) {
+            throw new IllegalArgumentException("cannot convert the null String");
+        }
+        String[] parts = addr.split(":");
+        if (parts.length != ETHER_ADDR_LEN) {
+            throw new IllegalArgumentException(addr + " was not a valid MAC address");
+        }
+        long longAddr = 0;
+        int index = ETHER_ADDR_LEN;
+        while (index-- > 0) {
+            int x = Integer.valueOf(parts[index], 16);
+            if (x < 0 || 0xff < x) {
+                throw new IllegalArgumentException(addr + "was not a valid MAC address");
+            }
+            longAddr = x + (longAddr << 8);
+        }
+        return longAddr;
+    }
+
+    /** @hide */
+    public static String stringAddrFromLongAddr(long addr) {
+        addr = Long.reverseBytes(addr) >> 16;
+        StringJoiner j = new StringJoiner(":");
+        for (int i = 0; i < ETHER_ADDR_LEN; i++) {
+            j.add(Integer.toHexString((byte) addr));
+            addr = addr >> 8;
+        }
+        return j.toString();
+    }
+
+    /**
+     * Returns a randomely generated mac address with the Android OUI value "DA-A1-19".
+     * The locally assigned bit is always set to 1.
+     */
+    public static MacAddress getRandomAddress() {
+        return getRandomAddress(BASE_ANDROID_MAC, new Random());
+    }
+
+    /**
+     * Returns a randomely generated mac address using the given Random object and the same
+     * OUI values as the given MacAddress. The locally assigned bit is always set to 1.
+     */
+    public static MacAddress getRandomAddress(MacAddress base, Random r) {
+        long longAddr = (base.mAddr & OUI_MASK) | (NIC_MASK & r.nextLong()) | LOCALLY_ASSIGNED_MASK;
+        return new MacAddress(longAddr);
+    }
+
+    // Convenience function for working around the lack of byte literals.
+    private static byte[] addr(int... in) {
+        if (in.length != ETHER_ADDR_LEN) {
+            throw new IllegalArgumentException(Arrays.toString(in)
+                    + " was not an array with length equal to " + ETHER_ADDR_LEN);
+        }
+        byte[] out = new byte[ETHER_ADDR_LEN];
+        for (int i = 0; i < ETHER_ADDR_LEN; i++) {
+            out[i] = (byte) in[i];
+        }
+        return out;
     }
 }