Fix a bug in InetAddressUtils, and add a test.

InetAddressUtils's parcelInetAddress and #unparcelInetAddress
methods do not correctly parcel scoped IPv6 addresses. Fix this
by using the same code that LinkProperties uses, and add a test.

Bug: 182785371
Test: atest NetworkStaticLibTests
Change-Id: Idc9fcbcf4b2b0746c19831fef68b0ddc206eb161

staticlibs/framework/com/android/net/module/util/InetAddressUtils.java

@@ -18,6 +18,7 @@ package com.android.net.module.util;
 
 import android.os.Parcel;
 
+import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 
@@ -27,6 +28,8 @@ import java.net.UnknownHostException;
  */
 public class InetAddressUtils {
 
+    private static final int INET6_ADDR_LENGTH = 16;
+
     /**
      * Writes an InetAddress to a parcel. The address may be null. This is likely faster than
      * calling writeSerializable.
@@ -35,6 +38,13 @@ public class InetAddressUtils {
     public static void parcelInetAddress(Parcel parcel, InetAddress address, int flags) {
         byte[] addressArray = (address != null) ? address.getAddress() : null;
         parcel.writeByteArray(addressArray);
+        if (address instanceof Inet6Address) {
+            final Inet6Address v6Address = (Inet6Address) address;
+            final boolean hasScopeId = v6Address.getScopeId() != 0;
+            parcel.writeBoolean(hasScopeId);
+            if (hasScopeId) parcel.writeInt(v6Address.getScopeId());
+        }
+
     }
 
     /**
@@ -47,7 +57,14 @@ public class InetAddressUtils {
         if (addressArray == null) {
             return null;
         }
+
         try {
+            if (addressArray.length == INET6_ADDR_LENGTH) {
+                final boolean hasScopeId = in.readBoolean();
+                final int scopeId = hasScopeId ? in.readInt() : 0;
+                return Inet6Address.getByAddress(null /* host */, addressArray, scopeId);
+            }
+
             return InetAddress.getByAddress(addressArray);
         } catch (UnknownHostException e) {
             return null;

staticlibs/tests/unit/src/com/android/net/module/util/InetAddressUtilsTest.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2020 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 com.android.net.module.util;
+
+import static junit.framework.Assert.assertEquals;
+
+import android.os.Parcel;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class InetAddressUtilsTest {
+
+    private InetAddress parcelUnparcelAddress(InetAddress addr) {
+        Parcel p = Parcel.obtain();
+        InetAddressUtils.parcelInetAddress(p, addr, 0 /* flags */);
+        p.setDataPosition(0);
+        byte[] marshalled = p.marshall();
+        p.recycle();
+        p = Parcel.obtain();
+        p.unmarshall(marshalled, 0, marshalled.length);
+        p.setDataPosition(0);
+        InetAddress out = InetAddressUtils.unparcelInetAddress(p);
+        p.recycle();
+        return out;
+    }
+
+    @Test
+    public void testParcelUnparcelIpv4Address() throws Exception {
+        InetAddress ipv4 = InetAddress.getByName("192.0.2.1");
+        assertEquals(ipv4, parcelUnparcelAddress(ipv4));
+    }
+
+    @Test
+    public void testParcelUnparcelIpv6Address() throws Exception {
+        InetAddress ipv6 = InetAddress.getByName("2001:db8::1");
+        assertEquals(ipv6, parcelUnparcelAddress(ipv6));
+    }
+
+    @Test
+    public void testParcelUnparcelScopedIpv6Address() throws Exception {
+        InetAddress ipv6 = InetAddress.getByName("fe80::1%42");
+        assertEquals(42, ((Inet6Address) ipv6).getScopeId());
+        Inet6Address out = (Inet6Address) parcelUnparcelAddress(ipv6);
+        assertEquals(ipv6, out);
+        assertEquals(42, out.getScopeId());
+    }
+}