Add android.net.IpPrefix#contains()

This was originally to avoid RuntimeException in RouteInfo#matches():
    When an IPv6 prefix with a length greater than the max permitted
    for IPv4 is matched against an Inet4Address, the call to
    NetworkUtils throws RuntimeException.

Change-Id: I92e2bd19a4e7d656cf682fd27678da07e211850d

core/java/android/net/IpPrefix.java

@@ -169,6 +169,21 @@ public final class IpPrefix implements Parcelable {
         return prefixLength;
     }
 
+    /**
+     * Determines whether the prefix contains the specified address.
+     *
+     * @param address An {@link InetAddress} to test.
+     * @return {@code true} if the prefix covers the given address.
+     */
+    public boolean contains(InetAddress address) {
+        byte[] addrBytes = (address == null) ? null : address.getAddress();
+        if (addrBytes == null || addrBytes.length != this.address.length) {
+            return false;
+        }
+        NetworkUtils.maskRawAddress(addrBytes, prefixLength);
+        return Arrays.equals(this.address, addrBytes);
+    }
+
     /**
      * Returns a string representation of this {@code IpPrefix}.
      *

core/java/android/net/RouteInfo.java

@@ -367,13 +367,7 @@ public final class RouteInfo implements Parcelable {
      * @return {@code true} if the destination and prefix length cover the given address.
      */
     public boolean matches(InetAddress destination) {
-        if (destination == null) return false;
-
-        // match the route destination and destination with prefix length
-        InetAddress dstNet = NetworkUtils.getNetworkPart(destination,
-                mDestination.getPrefixLength());
-
-        return mDestination.getAddress().equals(dstNet);
+        return mDestination.contains(destination);
     }
 
     /**

core/tests/coretests/src/android/net/IpPrefixTest.java

@@ -29,6 +29,10 @@ import junit.framework.TestCase;
 
 public class IpPrefixTest extends TestCase {
 
+    private static InetAddress Address(String addr) {
+        return InetAddress.parseNumericAddress(addr);
+    }
+
     // Explicitly cast everything to byte because "error: possible loss of precision".
     private static final byte[] IPV4_BYTES = { (byte) 192, (byte) 0, (byte) 2, (byte) 4};
     private static final byte[] IPV6_BYTES = {
@@ -208,6 +212,34 @@ public class IpPrefixTest extends TestCase {
         assertAreNotEqual(p1, p2);
     }
 
+    @SmallTest
+    public void testContains() {
+        IpPrefix p = new IpPrefix("2001:db8:f00::ace:d00d/127");
+        assertTrue(p.contains(Address("2001:db8:f00::ace:d00c")));
+        assertTrue(p.contains(Address("2001:db8:f00::ace:d00d")));
+        assertFalse(p.contains(Address("2001:db8:f00::ace:d00e")));
+        assertFalse(p.contains(Address("2001:db8:f00::bad:d00d")));
+        assertFalse(p.contains(Address("2001:4868:4860::8888")));
+        assertFalse(p.contains(null));
+        assertFalse(p.contains(Address("8.8.8.8")));
+
+        p = new IpPrefix("192.0.2.0/23");
+        assertTrue(p.contains(Address("192.0.2.43")));
+        assertTrue(p.contains(Address("192.0.3.21")));
+        assertFalse(p.contains(Address("192.0.0.21")));
+        assertFalse(p.contains(Address("8.8.8.8")));
+        assertFalse(p.contains(Address("2001:4868:4860::8888")));
+
+        IpPrefix ipv6Default = new IpPrefix("::/0");
+        assertTrue(ipv6Default.contains(Address("2001:db8::f00")));
+        assertFalse(ipv6Default.contains(Address("192.0.2.1")));
+
+        IpPrefix ipv4Default = new IpPrefix("0.0.0.0/0");
+        assertTrue(ipv4Default.contains(Address("255.255.255.255")));
+        assertTrue(ipv4Default.contains(Address("192.0.2.1")));
+        assertFalse(ipv4Default.contains(Address("2001:db8::f00")));
+    }
+
     @SmallTest
     public void testHashCode() {
         IpPrefix p;

core/tests/coretests/src/android/net/RouteInfoTest.java

@@ -90,6 +90,7 @@ public class RouteInfoTest extends TestCase {
         assertFalse(r.matches(Address("2001:db8:f00::ace:d00e")));
         assertFalse(r.matches(Address("2001:db8:f00::bad:d00d")));
         assertFalse(r.matches(Address("2001:4868:4860::8888")));
+        assertFalse(r.matches(Address("8.8.8.8")));
 
         r = new PatchedRouteInfo(Prefix("192.0.2.0/23"), null, "wlan0");
         assertTrue(r.matches(Address("192.0.2.43")));