Merge "Move Inet[4]AddressUtils to libs/net" into rvc-dev
diff --git a/common/Android.bp b/common/Android.bp
index d29ba36..d93579b 100644
--- a/common/Android.bp
+++ b/common/Android.bp
@@ -93,6 +93,7 @@
     srcs: [
         "src_frameworkcommon/android/net/util/nsd/DnsSdTxtRecord.java",
         "src_frameworkcommon/android/net/util/MacAddressUtils.java",
+        "src_frameworkcommon/com/android/net/module/util/**/*.java",
     ],
     path: "src_frameworkcommon",
     visibility: [
diff --git a/common/src_frameworkcommon/com/android/net/module/util/Inet4AddressUtils.java b/common/src_frameworkcommon/com/android/net/module/util/Inet4AddressUtils.java
new file mode 100644
index 0000000..a1d34a0
--- /dev/null
+++ b/common/src_frameworkcommon/com/android/net/module/util/Inet4AddressUtils.java
@@ -0,0 +1,166 @@
+/*
+ * 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 java.net.Inet4Address;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/**
+ * Collection of utilities to work with IPv4 addresses.
+ * @hide
+ */
+public class Inet4AddressUtils {
+
+    /**
+     * Convert a IPv4 address from an integer to an InetAddress (0x04030201 -> 1.2.3.4)
+     *
+     * <p>This method uses the higher-order int bytes as the lower-order IPv4 address bytes,
+     * which is an unusual convention. Consider {@link #intToInet4AddressHTH(int)} instead.
+     * @param hostAddress an int coding for an IPv4 address, where higher-order int byte is
+     *                    lower-order IPv4 address byte
+     */
+    public static Inet4Address intToInet4AddressHTL(int hostAddress) {
+        return intToInet4AddressHTH(Integer.reverseBytes(hostAddress));
+    }
+
+    /**
+     * Convert a IPv4 address from an integer to an InetAddress (0x01020304 -> 1.2.3.4)
+     * @param hostAddress an int coding for an IPv4 address
+     */
+    public static Inet4Address intToInet4AddressHTH(int hostAddress) {
+        byte[] addressBytes = { (byte) (0xff & (hostAddress >> 24)),
+                (byte) (0xff & (hostAddress >> 16)),
+                (byte) (0xff & (hostAddress >> 8)),
+                (byte) (0xff & hostAddress) };
+
+        try {
+            return (Inet4Address) InetAddress.getByAddress(addressBytes);
+        } catch (UnknownHostException e) {
+            throw new AssertionError();
+        }
+    }
+
+    /**
+     * Convert an IPv4 address from an InetAddress to an integer (1.2.3.4 -> 0x01020304)
+     *
+     * <p>This conversion can help order IP addresses: considering the ordering
+     * 192.0.2.1 < 192.0.2.2 < ..., resulting ints will follow that ordering if read as unsigned
+     * integers with {@link Integer#toUnsignedLong}.
+     * @param inetAddr is an InetAddress corresponding to the IPv4 address
+     * @return the IP address as integer
+     */
+    public static int inet4AddressToIntHTH(Inet4Address inetAddr)
+            throws IllegalArgumentException {
+        byte [] addr = inetAddr.getAddress();
+        return ((addr[0] & 0xff) << 24) | ((addr[1] & 0xff) << 16)
+                | ((addr[2] & 0xff) << 8) | (addr[3] & 0xff);
+    }
+
+    /**
+     * Convert a IPv4 address from an InetAddress to an integer (1.2.3.4 -> 0x04030201)
+     *
+     * <p>This method stores the higher-order IPv4 address bytes in the lower-order int bytes,
+     * which is an unusual convention. Consider {@link #inet4AddressToIntHTH(Inet4Address)} instead.
+     * @param inetAddr is an InetAddress corresponding to the IPv4 address
+     * @return the IP address as integer
+     */
+    public static int inet4AddressToIntHTL(Inet4Address inetAddr) {
+        return Integer.reverseBytes(inet4AddressToIntHTH(inetAddr));
+    }
+
+    /**
+     * Convert a network prefix length to an IPv4 netmask integer (prefixLength 17 -> 0xffff8000)
+     * @return the IPv4 netmask as an integer
+     */
+    public static int prefixLengthToV4NetmaskIntHTH(int prefixLength)
+            throws IllegalArgumentException {
+        if (prefixLength < 0 || prefixLength > 32) {
+            throw new IllegalArgumentException("Invalid prefix length (0 <= prefix <= 32)");
+        }
+        // (int)a << b is equivalent to a << (b & 0x1f): can't shift by 32 (-1 << 32 == -1)
+        return prefixLength == 0 ? 0 : 0xffffffff << (32 - prefixLength);
+    }
+
+    /**
+     * Convert a network prefix length to an IPv4 netmask integer (prefixLength 17 -> 0x0080ffff).
+     *
+     * <p>This method stores the higher-order IPv4 address bytes in the lower-order int bytes,
+     * which is an unusual convention. Consider {@link #prefixLengthToV4NetmaskIntHTH(int)} instead.
+     * @return the IPv4 netmask as an integer
+     */
+    public static int prefixLengthToV4NetmaskIntHTL(int prefixLength)
+            throws IllegalArgumentException {
+        return Integer.reverseBytes(prefixLengthToV4NetmaskIntHTH(prefixLength));
+    }
+
+    /**
+     * Convert an IPv4 netmask to a prefix length, checking that the netmask is contiguous.
+     * @param netmask as a {@code Inet4Address}.
+     * @return the network prefix length
+     * @throws IllegalArgumentException the specified netmask was not contiguous.
+     * @hide
+     */
+    public static int netmaskToPrefixLength(Inet4Address netmask) {
+        // inetAddressToInt returns an int in *network* byte order.
+        int i = inet4AddressToIntHTH(netmask);
+        int prefixLength = Integer.bitCount(i);
+        int trailingZeros = Integer.numberOfTrailingZeros(i);
+        if (trailingZeros != 32 - prefixLength) {
+            throw new IllegalArgumentException("Non-contiguous netmask: " + Integer.toHexString(i));
+        }
+        return prefixLength;
+    }
+
+    /**
+     * Returns the implicit netmask of an IPv4 address, as was the custom before 1993.
+     */
+    public static int getImplicitNetmask(Inet4Address address) {
+        int firstByte = address.getAddress()[0] & 0xff;  // Convert to an unsigned value.
+        if (firstByte < 128) {
+            return 8;
+        } else if (firstByte < 192) {
+            return 16;
+        } else if (firstByte < 224) {
+            return 24;
+        } else {
+            return 32;  // Will likely not end well for other reasons.
+        }
+    }
+
+    /**
+     * Get the broadcast address for a given prefix.
+     *
+     * <p>For example 192.168.0.1/24 -> 192.168.0.255
+     */
+    public static Inet4Address getBroadcastAddress(Inet4Address addr, int prefixLength)
+            throws IllegalArgumentException {
+        final int intBroadcastAddr = inet4AddressToIntHTH(addr)
+                | ~prefixLengthToV4NetmaskIntHTH(prefixLength);
+        return intToInet4AddressHTH(intBroadcastAddr);
+    }
+
+    /**
+     * Get a prefix mask as Inet4Address for a given prefix length.
+     *
+     * <p>For example 20 -> 255.255.240.0
+     */
+    public static Inet4Address getPrefixMaskAsInet4Address(int prefixLength)
+            throws IllegalArgumentException {
+        return intToInet4AddressHTH(prefixLengthToV4NetmaskIntHTH(prefixLength));
+    }
+}
diff --git a/common/src_frameworkcommon/com/android/net/module/util/InetAddressUtils.java b/common/src_frameworkcommon/com/android/net/module/util/InetAddressUtils.java
new file mode 100644
index 0000000..6300328
--- /dev/null
+++ b/common/src_frameworkcommon/com/android/net/module/util/InetAddressUtils.java
@@ -0,0 +1,58 @@
+/*
+ * 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 android.os.Parcel;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/**
+ * Collection of utilities to interact with {@link InetAddress}
+ * @hide
+ */
+public class InetAddressUtils {
+
+    /**
+     * Writes an InetAddress to a parcel. The address may be null. This is likely faster than
+     * calling writeSerializable.
+     * @hide
+     */
+    public static void parcelInetAddress(Parcel parcel, InetAddress address, int flags) {
+        byte[] addressArray = (address != null) ? address.getAddress() : null;
+        parcel.writeByteArray(addressArray);
+    }
+
+    /**
+     * Reads an InetAddress from a parcel. Returns null if the address that was written was null
+     * or if the data is invalid.
+     * @hide
+     */
+    public static InetAddress unparcelInetAddress(Parcel in) {
+        byte[] addressArray = in.createByteArray();
+        if (addressArray == null) {
+            return null;
+        }
+        try {
+            return InetAddress.getByAddress(addressArray);
+        } catch (UnknownHostException e) {
+            return null;
+        }
+    }
+
+    private InetAddressUtils() {}
+}
diff --git a/common/tests/unit/Android.bp b/common/tests/unit/Android.bp
index 52c5f82..cb15277 100644
--- a/common/tests/unit/Android.bp
+++ b/common/tests/unit/Android.bp
@@ -5,6 +5,7 @@
 android_library {
     name: "NetworkStaticLibTestsLib",
     srcs: ["src/**/*.java","src/**/*.kt"],
+    min_sdk_version: "29",
     jarjar_rules: "jarjar-rules.txt",
     static_libs: [
         "net-utils-framework-common",
@@ -16,6 +17,7 @@
     ],
     visibility: [
         "//frameworks/base/packages/Tethering/tests/integration",
+        "//packages/modules/NetworkStack/tests/integration",
     ]
 }
 
diff --git a/common/tests/unit/src/com/android/net/module/util/Inet4AddressUtilsTest.java b/common/tests/unit/src/com/android/net/module/util/Inet4AddressUtilsTest.java
new file mode 100644
index 0000000..5d5ed91
--- /dev/null
+++ b/common/tests/unit/src/com/android/net/module/util/Inet4AddressUtilsTest.java
@@ -0,0 +1,210 @@
+/*
+ * 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 com.android.net.module.util.Inet4AddressUtils.getBroadcastAddress;
+import static com.android.net.module.util.Inet4AddressUtils.getImplicitNetmask;
+import static com.android.net.module.util.Inet4AddressUtils.getPrefixMaskAsInet4Address;
+import static com.android.net.module.util.Inet4AddressUtils.inet4AddressToIntHTH;
+import static com.android.net.module.util.Inet4AddressUtils.inet4AddressToIntHTL;
+import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTH;
+import static com.android.net.module.util.Inet4AddressUtils.intToInet4AddressHTL;
+import static com.android.net.module.util.Inet4AddressUtils.netmaskToPrefixLength;
+import static com.android.net.module.util.Inet4AddressUtils.prefixLengthToV4NetmaskIntHTH;
+import static com.android.net.module.util.Inet4AddressUtils.prefixLengthToV4NetmaskIntHTL;
+
+import static junit.framework.Assert.assertEquals;
+
+import static org.junit.Assert.fail;
+
+import android.net.InetAddresses;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.net.Inet4Address;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class Inet4AddressUtilsTest {
+
+    @Test
+    public void testInet4AddressToIntHTL() {
+        assertEquals(0, inet4AddressToIntHTL(ipv4Address("0.0.0.0")));
+        assertEquals(0x000080ff, inet4AddressToIntHTL(ipv4Address("255.128.0.0")));
+        assertEquals(0x0080ff0a, inet4AddressToIntHTL(ipv4Address("10.255.128.0")));
+        assertEquals(0x00feff0a, inet4AddressToIntHTL(ipv4Address("10.255.254.0")));
+        assertEquals(0xfeffa8c0, inet4AddressToIntHTL(ipv4Address("192.168.255.254")));
+        assertEquals(0xffffa8c0, inet4AddressToIntHTL(ipv4Address("192.168.255.255")));
+    }
+
+    @Test
+    public void testIntToInet4AddressHTL() {
+        assertEquals(ipv4Address("0.0.0.0"), intToInet4AddressHTL(0));
+        assertEquals(ipv4Address("255.128.0.0"), intToInet4AddressHTL(0x000080ff));
+        assertEquals(ipv4Address("10.255.128.0"), intToInet4AddressHTL(0x0080ff0a));
+        assertEquals(ipv4Address("10.255.254.0"), intToInet4AddressHTL(0x00feff0a));
+        assertEquals(ipv4Address("192.168.255.254"), intToInet4AddressHTL(0xfeffa8c0));
+        assertEquals(ipv4Address("192.168.255.255"), intToInet4AddressHTL(0xffffa8c0));
+    }
+
+    @Test
+    public void testInet4AddressToIntHTH() {
+        assertEquals(0, inet4AddressToIntHTH(ipv4Address("0.0.0.0")));
+        assertEquals(0xff800000, inet4AddressToIntHTH(ipv4Address("255.128.0.0")));
+        assertEquals(0x0aff8000, inet4AddressToIntHTH(ipv4Address("10.255.128.0")));
+        assertEquals(0x0afffe00, inet4AddressToIntHTH(ipv4Address("10.255.254.0")));
+        assertEquals(0xc0a8fffe, inet4AddressToIntHTH(ipv4Address("192.168.255.254")));
+        assertEquals(0xc0a8ffff, inet4AddressToIntHTH(ipv4Address("192.168.255.255")));
+    }
+
+    @Test
+    public void testIntToInet4AddressHTH() {
+        assertEquals(ipv4Address("0.0.0.0"), intToInet4AddressHTH(0));
+        assertEquals(ipv4Address("255.128.0.0"), intToInet4AddressHTH(0xff800000));
+        assertEquals(ipv4Address("10.255.128.0"), intToInet4AddressHTH(0x0aff8000));
+        assertEquals(ipv4Address("10.255.254.0"), intToInet4AddressHTH(0x0afffe00));
+        assertEquals(ipv4Address("192.168.255.254"), intToInet4AddressHTH(0xc0a8fffe));
+        assertEquals(ipv4Address("192.168.255.255"), intToInet4AddressHTH(0xc0a8ffff));
+    }
+
+
+    @Test
+    public void testPrefixLengthToV4NetmaskIntHTL() {
+        assertEquals(0, prefixLengthToV4NetmaskIntHTL(0));
+        assertEquals(0x000080ff /* 255.128.0.0 */, prefixLengthToV4NetmaskIntHTL(9));
+        assertEquals(0x0080ffff /* 255.255.128.0 */, prefixLengthToV4NetmaskIntHTL(17));
+        assertEquals(0x00feffff /* 255.255.254.0 */, prefixLengthToV4NetmaskIntHTL(23));
+        assertEquals(0xfeffffff /* 255.255.255.254 */, prefixLengthToV4NetmaskIntHTL(31));
+        assertEquals(0xffffffff /* 255.255.255.255 */, prefixLengthToV4NetmaskIntHTL(32));
+    }
+
+    @Test
+    public void testPrefixLengthToV4NetmaskIntHTH() {
+        assertEquals(0, prefixLengthToV4NetmaskIntHTH(0));
+        assertEquals(0xff800000 /* 255.128.0.0 */, prefixLengthToV4NetmaskIntHTH(9));
+        assertEquals(0xffff8000 /* 255.255.128.0 */, prefixLengthToV4NetmaskIntHTH(17));
+        assertEquals(0xfffffe00 /* 255.255.254.0 */, prefixLengthToV4NetmaskIntHTH(23));
+        assertEquals(0xfffffffe /* 255.255.255.254 */, prefixLengthToV4NetmaskIntHTH(31));
+        assertEquals(0xffffffff /* 255.255.255.255 */, prefixLengthToV4NetmaskIntHTH(32));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testPrefixLengthToV4NetmaskIntHTH_NegativeLength() {
+        prefixLengthToV4NetmaskIntHTH(-1);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testPrefixLengthToV4NetmaskIntHTH_LengthTooLarge() {
+        prefixLengthToV4NetmaskIntHTH(33);
+    }
+
+    private void checkAddressMasking(String expectedAddr, String addr, int prefixLength) {
+        final int prefix = prefixLengthToV4NetmaskIntHTH(prefixLength);
+        final int addrInt = inet4AddressToIntHTH(ipv4Address(addr));
+        assertEquals(ipv4Address(expectedAddr), intToInet4AddressHTH(prefix & addrInt));
+    }
+
+    @Test
+    public void testPrefixLengthToV4NetmaskIntHTH_MaskAddr() {
+        checkAddressMasking("192.168.0.0", "192.168.128.1", 16);
+        checkAddressMasking("255.240.0.0", "255.255.255.255", 12);
+        checkAddressMasking("255.255.255.255", "255.255.255.255", 32);
+        checkAddressMasking("0.0.0.0", "255.255.255.255", 0);
+    }
+
+    @Test
+    public void testGetImplicitNetmask() {
+        assertEquals(8, getImplicitNetmask(ipv4Address("4.2.2.2")));
+        assertEquals(8, getImplicitNetmask(ipv4Address("10.5.6.7")));
+        assertEquals(16, getImplicitNetmask(ipv4Address("173.194.72.105")));
+        assertEquals(16, getImplicitNetmask(ipv4Address("172.23.68.145")));
+        assertEquals(24, getImplicitNetmask(ipv4Address("192.0.2.1")));
+        assertEquals(24, getImplicitNetmask(ipv4Address("192.168.5.1")));
+        assertEquals(32, getImplicitNetmask(ipv4Address("224.0.0.1")));
+        assertEquals(32, getImplicitNetmask(ipv4Address("255.6.7.8")));
+    }
+
+    private void assertInvalidNetworkMask(Inet4Address addr) {
+        try {
+            netmaskToPrefixLength(addr);
+            fail("Invalid netmask " + addr.getHostAddress() + " did not cause exception");
+        } catch (IllegalArgumentException expected) {
+        }
+    }
+
+    @Test
+    public void testNetmaskToPrefixLength() {
+        assertEquals(0, netmaskToPrefixLength(ipv4Address("0.0.0.0")));
+        assertEquals(9, netmaskToPrefixLength(ipv4Address("255.128.0.0")));
+        assertEquals(17, netmaskToPrefixLength(ipv4Address("255.255.128.0")));
+        assertEquals(23, netmaskToPrefixLength(ipv4Address("255.255.254.0")));
+        assertEquals(31, netmaskToPrefixLength(ipv4Address("255.255.255.254")));
+        assertEquals(32, netmaskToPrefixLength(ipv4Address("255.255.255.255")));
+
+        assertInvalidNetworkMask(ipv4Address("0.0.0.1"));
+        assertInvalidNetworkMask(ipv4Address("255.255.255.253"));
+        assertInvalidNetworkMask(ipv4Address("255.255.0.255"));
+    }
+
+    @Test
+    public void testGetPrefixMaskAsAddress() {
+        assertEquals("255.255.240.0", getPrefixMaskAsInet4Address(20).getHostAddress());
+        assertEquals("255.0.0.0", getPrefixMaskAsInet4Address(8).getHostAddress());
+        assertEquals("0.0.0.0", getPrefixMaskAsInet4Address(0).getHostAddress());
+        assertEquals("255.255.255.255", getPrefixMaskAsInet4Address(32).getHostAddress());
+    }
+
+    @Test
+    public void testGetBroadcastAddress() {
+        assertEquals("192.168.15.255",
+                getBroadcastAddress(ipv4Address("192.168.0.123"), 20).getHostAddress());
+        assertEquals("192.255.255.255",
+                getBroadcastAddress(ipv4Address("192.168.0.123"), 8).getHostAddress());
+        assertEquals("192.168.0.123",
+                getBroadcastAddress(ipv4Address("192.168.0.123"), 32).getHostAddress());
+        assertEquals("255.255.255.255",
+                getBroadcastAddress(ipv4Address("192.168.0.123"), 0).getHostAddress());
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetBroadcastAddress_PrefixTooLarge() {
+        getBroadcastAddress(ipv4Address("192.168.0.123"), 33);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetBroadcastAddress_NegativePrefix() {
+        getBroadcastAddress(ipv4Address("192.168.0.123"), -1);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetPrefixMaskAsAddress_PrefixTooLarge() {
+        getPrefixMaskAsInet4Address(33);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetPrefixMaskAsAddress_NegativePrefix() {
+        getPrefixMaskAsInet4Address(-1);
+    }
+
+    private Inet4Address ipv4Address(String addr) {
+        return (Inet4Address) InetAddresses.parseNumericAddress(addr);
+    }
+}