1 /*
2  * Copyright (C) 2020 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.net.module.util;
18 
19 
20 import android.annotation.Nullable;
21 
22 import java.net.Inet6Address;
23 import java.net.InetAddress;
24 
25 /**
26  * Various utilities used in connectivity code.
27  * @hide
28  */
29 public final class ConnectivityUtils {
ConnectivityUtils()30     private ConnectivityUtils() {}
31 
32 
33     /**
34      * Return IP address and port in a string format.
35      */
addressAndPortToString(InetAddress address, int port)36     public static String addressAndPortToString(InetAddress address, int port) {
37         return String.format(
38                 (address instanceof Inet6Address) ? "[%s]:%d" : "%s:%d",
39                         address.getHostAddress(), port);
40     }
41 
42     /**
43      * Return true if the provided address is non-null and an IPv6 Unique Local Address (RFC4193).
44      */
isIPv6ULA(@ullable InetAddress addr)45     public static boolean isIPv6ULA(@Nullable InetAddress addr) {
46         return addr instanceof Inet6Address
47                 && ((addr.getAddress()[0] & 0xfe) == 0xfc);
48     }
49 
50     /**
51      * Returns the {@code int} nearest in value to {@code value}.
52      *
53      * @param value any {@code long} value
54      * @return the same value cast to {@code int} if it is in the range of the {@code int}
55      * type, {@link Integer#MAX_VALUE} if it is too large, or {@link Integer#MIN_VALUE} if
56      * it is too small
57      */
saturatedCast(long value)58     public static int saturatedCast(long value) {
59         if (value > Integer.MAX_VALUE) {
60             return Integer.MAX_VALUE;
61         }
62         if (value < Integer.MIN_VALUE) {
63             return Integer.MIN_VALUE;
64         }
65         return (int) value;
66     }
67 }
68