Eran Messeri | 309e071 | 2018-11-20 08:42:42 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 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 android.net; |
| 18 | |
| 19 | import android.annotation.NonNull; |
| 20 | import android.util.Log; |
| 21 | |
| 22 | import java.io.IOException; |
| 23 | import java.net.InetSocketAddress; |
| 24 | |
| 25 | import javax.net.SocketFactory; |
| 26 | import javax.net.ssl.SSLSocket; |
| 27 | import javax.net.ssl.SSLSocketFactory; |
| 28 | |
| 29 | /** |
| 30 | * Class for testing connectivity to DNS-over-TLS servers. |
| 31 | * {@hide} |
| 32 | */ |
| 33 | public class PrivateDnsConnectivityChecker { |
| 34 | private static final String TAG = "NetworkUtils"; |
| 35 | |
| 36 | private static final int PRIVATE_DNS_PORT = 853; |
| 37 | private static final int CONNECTION_TIMEOUT_MS = 5000; |
| 38 | |
| 39 | private PrivateDnsConnectivityChecker() { } |
| 40 | |
| 41 | /** |
| 42 | * checks that a provided host can perform a TLS handshake on port 853. |
| 43 | * @param hostname host to connect to. |
| 44 | */ |
| 45 | public static boolean canConnectToPrivateDnsServer(@NonNull String hostname) { |
| 46 | final SocketFactory factory = SSLSocketFactory.getDefault(); |
| 47 | TrafficStats.setThreadStatsTag(TrafficStats.TAG_SYSTEM_APP); |
| 48 | |
| 49 | try (SSLSocket socket = (SSLSocket) factory.createSocket()) { |
| 50 | socket.setSoTimeout(CONNECTION_TIMEOUT_MS); |
| 51 | socket.connect(new InetSocketAddress(hostname, PRIVATE_DNS_PORT)); |
| 52 | if (!socket.isConnected()) { |
| 53 | Log.w(TAG, String.format("Connection to %s failed.", hostname)); |
| 54 | return false; |
| 55 | } |
| 56 | socket.startHandshake(); |
| 57 | Log.w(TAG, String.format("TLS handshake to %s succeeded.", hostname)); |
| 58 | return true; |
| 59 | } catch (IOException e) { |
| 60 | Log.w(TAG, String.format("TLS handshake to %s failed.", hostname), e); |
| 61 | return false; |
| 62 | } |
| 63 | } |
| 64 | } |