Move shared methods to net shared lib

The NetworkUtils.getNetworkPart() method is used by Settings
and wifi. NetworkUtils is inside the incoming connectivity
module. It will become inaccessible outside the module, so
move the shared methods to shared lib and also move the
related helper method.

The corresponding usgae is also updated.

Bug: 172183305
Test: atest FrameworksNetTests
Change-Id: I47410afa27aad61f63759df41be959f323c1d100

framework/src/android/net/IpPrefix.java

@@ -23,6 +23,8 @@ import android.os.Parcel;
 import android.os.Parcelable;
 import android.util.Pair;
 
+import com.android.net.module.util.NetUtils;
+
 import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
@@ -58,7 +60,7 @@ public final class IpPrefix implements Parcelable {
             throw new IllegalArgumentException(
                     "IpPrefix has " + address.length + " bytes which is neither 4 nor 16");
         }
-        NetworkUtils.maskRawAddress(address, prefixLength);
+        NetUtils.maskRawAddress(address, prefixLength);
     }
 
     /**
@@ -189,7 +191,7 @@ public final class IpPrefix implements Parcelable {
         if (addrBytes == null || addrBytes.length != this.address.length) {
             return false;
         }
-        NetworkUtils.maskRawAddress(addrBytes, prefixLength);
+        NetUtils.maskRawAddress(addrBytes, prefixLength);
         return Arrays.equals(this.address, addrBytes);
     }
 
@@ -203,7 +205,7 @@ public final class IpPrefix implements Parcelable {
     public boolean containsPrefix(@NonNull IpPrefix otherPrefix) {
         if (otherPrefix.getPrefixLength() < prefixLength) return false;
         final byte[] otherAddress = otherPrefix.getRawAddress();
-        NetworkUtils.maskRawAddress(otherAddress, prefixLength);
+        NetUtils.maskRawAddress(otherAddress, prefixLength);
         return Arrays.equals(otherAddress, address);
     }
 

framework/src/android/net/NetworkUtils.java

@@ -29,7 +29,6 @@ import java.math.BigInteger;
 import java.net.Inet4Address;
 import java.net.InetAddress;
 import java.net.SocketException;
-import java.net.UnknownHostException;
 import java.util.Locale;
 import java.util.TreeSet;
 
@@ -231,46 +230,6 @@ public class NetworkUtils {
         return InetAddress.parseNumericAddress(addrString);
     }
 
-    /**
-     *  Masks a raw IP address byte array with the specified prefix length.
-     */
-    public static void maskRawAddress(byte[] array, int prefixLength) {
-        if (prefixLength < 0 || prefixLength > array.length * 8) {
-            throw new RuntimeException("IP address with " + array.length +
-                    " bytes has invalid prefix length " + prefixLength);
-        }
-
-        int offset = prefixLength / 8;
-        int remainder = prefixLength % 8;
-        byte mask = (byte)(0xFF << (8 - remainder));
-
-        if (offset < array.length) array[offset] = (byte)(array[offset] & mask);
-
-        offset++;
-
-        for (; offset < array.length; offset++) {
-            array[offset] = 0;
-        }
-    }
-
-    /**
-     * Get InetAddress masked with prefixLength.  Will never return null.
-     * @param address the IP address to mask with
-     * @param prefixLength the prefixLength used to mask the IP
-     */
-    public static InetAddress getNetworkPart(InetAddress address, int prefixLength) {
-        byte[] array = address.getAddress();
-        maskRawAddress(array, prefixLength);
-
-        InetAddress netPart = null;
-        try {
-            netPart = InetAddress.getByAddress(array);
-        } catch (UnknownHostException e) {
-            throw new RuntimeException("getNetworkPart error - " + e.toString());
-        }
-        return netPart;
-    }
-
     /**
      * Returns the implicit netmask of an IPv4 address, as was the custom before 1993.
      */