Add two utility methods for IPv4 netmasks.

1. Add a validating method to convert a netmask to a prefix length.
2. Add a function to get the implicit netmask of an IPv4 address.
3. Add a unit test.

Bug: 19704592
Change-Id: Icb9f58d3903ea01df9e3720383c9bd5db6dd8f26

1 files changed, 70 insertions, 0 deletions

diff --git a/core/tests/coretests/src/android/net/NetworkUtilsTest.java b/core/tests/coretests/src/android/net/NetworkUtilsTest.java
new file mode 100644
index 0000000..8d51c3b
--- /dev/null
+++ b/core/tests/coretests/src/android/net/NetworkUtilsTest.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2015 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 android.net.NetworkUtils;
+import android.test.suitebuilder.annotation.SmallTest;
+
+import java.net.Inet4Address;
+import java.net.InetAddress;
+
+import junit.framework.TestCase;
+
+public class NetworkUtilsTest extends TestCase {
+
+    private InetAddress Address(String addr) {
+        return InetAddress.parseNumericAddress(addr);
+    }
+
+    private Inet4Address IPv4Address(String addr) {
+        return (Inet4Address) Address(addr);
+    }
+
+    @SmallTest
+    public void testGetImplicitNetmask() {
+        assertEquals(8, NetworkUtils.getImplicitNetmask(IPv4Address("4.2.2.2")));
+        assertEquals(8, NetworkUtils.getImplicitNetmask(IPv4Address("10.5.6.7")));
+        assertEquals(16, NetworkUtils.getImplicitNetmask(IPv4Address("173.194.72.105")));
+        assertEquals(16, NetworkUtils.getImplicitNetmask(IPv4Address("172.23.68.145")));
+        assertEquals(24, NetworkUtils.getImplicitNetmask(IPv4Address("192.0.2.1")));
+        assertEquals(24, NetworkUtils.getImplicitNetmask(IPv4Address("192.168.5.1")));
+        assertEquals(32, NetworkUtils.getImplicitNetmask(IPv4Address("224.0.0.1")));
+        assertEquals(32, NetworkUtils.getImplicitNetmask(IPv4Address("255.6.7.8")));
+    }
+
+    private void assertInvalidNetworkMask(Inet4Address addr) {
+        try {
+            NetworkUtils.netmaskToPrefixLength(addr);
+            fail("Invalid netmask " + addr.getHostAddress() + " did not cause exception");
+        } catch (IllegalArgumentException expected) {
+        }
+    }
+
+    @SmallTest
+    public void testNetmaskToPrefixLength() {
+        assertEquals(0, NetworkUtils.netmaskToPrefixLength(IPv4Address("0.0.0.0")));
+        assertEquals(9, NetworkUtils.netmaskToPrefixLength(IPv4Address("255.128.0.0")));
+        assertEquals(17, NetworkUtils.netmaskToPrefixLength(IPv4Address("255.255.128.0")));
+        assertEquals(23, NetworkUtils.netmaskToPrefixLength(IPv4Address("255.255.254.0")));
+        assertEquals(31, NetworkUtils.netmaskToPrefixLength(IPv4Address("255.255.255.254")));
+        assertEquals(32, NetworkUtils.netmaskToPrefixLength(IPv4Address("255.255.255.255")));
+
+        assertInvalidNetworkMask(IPv4Address("0.0.0.1"));
+        assertInvalidNetworkMask(IPv4Address("255.255.255.253"));
+        assertInvalidNetworkMask(IPv4Address("255.255.0.255"));
+    }
+}