Move Inet[4]AddressUtils to libs/net

The classes should not be picked up from frameworks/base, as they are
part of several mainline modules.

Also refine comments in DhcpResults following feedback in previous
change.

Bug: 151052811
Test: m; manual: flashed, wifi and telephony working
Test: atest NetworkStackCoverageTests
Change-Id: I7074651c6a2a7a6b11bcf13cc4bb03833d7d655f

5 files changed, 5 insertions, 227 deletions

diff --git a/core/java/android/net/DhcpResults.java b/core/java/android/net/DhcpResults.java
index 5ab035496a43..1ef4f1741e3a 100644
--- a/core/java/android/net/DhcpResults.java
+++ b/core/java/android/net/DhcpResults.java
@@ -18,12 +18,13 @@ package android.net;
 
 import android.annotation.Nullable;
 import android.compat.annotation.UnsupportedAppUsage;
-import android.net.shared.InetAddressUtils;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.text.TextUtils;
 import android.util.Log;
 
+import com.android.net.module.util.InetAddressUtils;
+
 import java.net.Inet4Address;
 import java.net.InetAddress;
 import java.util.ArrayList;
diff --git a/core/java/android/net/NetworkUtils.java b/core/java/android/net/NetworkUtils.java
index 779f7bc91e8f..b5095a41801e 100644
--- a/core/java/android/net/NetworkUtils.java
+++ b/core/java/android/net/NetworkUtils.java
@@ -21,13 +21,14 @@ import static android.system.OsConstants.AF_INET6;
 
 import android.annotation.NonNull;
 import android.compat.annotation.UnsupportedAppUsage;
-import android.net.shared.Inet4AddressUtils;
 import android.os.Build;
 import android.system.ErrnoException;
 import android.system.Os;
 import android.util.Log;
 import android.util.Pair;
 
+import com.android.net.module.util.Inet4AddressUtils;
+
 import java.io.FileDescriptor;
 import java.math.BigInteger;
 import java.net.Inet4Address;
diff --git a/core/java/android/net/StaticIpConfiguration.java b/core/java/android/net/StaticIpConfiguration.java
index f24a9bd53039..a973455baa04 100644
--- a/core/java/android/net/StaticIpConfiguration.java
+++ b/core/java/android/net/StaticIpConfiguration.java
@@ -21,11 +21,11 @@ import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.compat.annotation.UnsupportedAppUsage;
-import android.net.shared.InetAddressUtils;
 import android.os.Parcel;
 import android.os.Parcelable;
 
 import com.android.internal.util.Preconditions;
+import com.android.net.module.util.InetAddressUtils;
 
 import java.net.InetAddress;
 import java.util.ArrayList;
diff --git a/core/java/android/net/shared/Inet4AddressUtils.java b/core/java/android/net/shared/Inet4AddressUtils.java
deleted file mode 100644
index bec0c84fa689..000000000000
--- a/core/java/android/net/shared/Inet4AddressUtils.java
+++ /dev/null
@@ -1,166 +0,0 @@
-/*
- * Copyright (C) 2019 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.shared;
-
-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/core/java/android/net/shared/InetAddressUtils.java b/core/java/android/net/shared/InetAddressUtils.java
deleted file mode 100644
index c9ee3a7cce4b..000000000000
--- a/core/java/android/net/shared/InetAddressUtils.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright (C) 2012 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.shared;
-
-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() {}
-}