Merge "MacAddress: Use SecureRandom and add a 46 bit randomized MAC generator" (9f168287) · Commits · e / os / android_frameworks_base

core/java/android/net/MacAddress.java

+24 −5

Original line number	Diff line number	Diff line
		@@ -26,6 +26,7 @@ import com.android.internal.util.Preconditions;

		import java.lang.annotation.Retention;
		import java.lang.annotation.RetentionPolicy;
		import java.security.SecureRandom;
		import java.util.Arrays;
		import java.util.Random;

		@@ -329,16 +330,34 @@ public final class MacAddress implements Parcelable {

		/**
		* Returns a generated MAC address whose 24 least significant bits constituting the
		* NIC part of the address are randomly selected.
		* NIC part of the address are randomly selected and has Google OUI base.
		*
		* The locally assigned bit is always set to 1. The multicast bit is always set to 0.
		*
		* @return a random locally assigned MacAddress.
		* @return a random locally assigned, unicast MacAddress with Google OUI.
		*
		* @hide
		*/
		public static @NonNull MacAddress createRandomUnicastAddressWithGoogleBase() {
		return createRandomUnicastAddress(BASE_GOOGLE_MAC, new SecureRandom());
		}

		/**
		* Returns a generated MAC address whose 46 bits, excluding the locally assigned bit and the
		* unicast bit, are randomly selected.
		*
		* The locally assigned bit is always set to 1. The multicast bit is always set to 0.
		*
		* @return a random locally assigned, unicast MacAddress.
		*
		* @hide
		*/
		public static @NonNull MacAddress createRandomUnicastAddress() {
		return createRandomUnicastAddress(BASE_GOOGLE_MAC, new Random());
		SecureRandom r = new SecureRandom();
		long addr = r.nextLong() & VALID_LONG_MASK;
		addr \|= LOCALLY_ASSIGNED_MASK;
		addr &= ~MULTICAST_MASK;
		return new MacAddress(addr);
		}

		/**
		@@ -355,8 +374,8 @@ public final class MacAddress implements Parcelable {
		*/
		public static @NonNull MacAddress createRandomUnicastAddress(MacAddress base, Random r) {
		long addr = (base.mAddr & OUI_MASK) \| (NIC_MASK & r.nextLong());
		addr = addr \| LOCALLY_ASSIGNED_MASK;
		addr = addr & ~MULTICAST_MASK;
		addr \|= LOCALLY_ASSIGNED_MASK;
		addr &= ~MULTICAST_MASK;
		return new MacAddress(addr);
		}

tests/net/java/android/net/MacAddressTest.java

+10 −1

Original line number	Diff line number	Diff line
		@@ -172,7 +172,7 @@ public class MacAddressTest {
		final int iterations = 1000;
		final String expectedAndroidOui = "da:a1:19";
		for (int i = 0; i < iterations; i++) {
		MacAddress mac = MacAddress.createRandomUnicastAddress();
		MacAddress mac = MacAddress.createRandomUnicastAddressWithGoogleBase();
		String stringRepr = mac.toString();

		assertTrue(stringRepr + " expected to be a locally assigned address",
		@@ -195,6 +195,15 @@ public class MacAddressTest {
		assertTrue(stringRepr + " expected to begin with " + expectedLocalOui,
		stringRepr.startsWith(expectedLocalOui));
		}

		for (int i = 0; i < iterations; i++) {
		MacAddress mac = MacAddress.createRandomUnicastAddress();
		String stringRepr = mac.toString();

		assertTrue(stringRepr + " expected to be a locally assigned address",
		mac.isLocallyAssigned());
		assertEquals(MacAddress.TYPE_UNICAST, mac.getAddressType());
		}
		}

		@Test