aboutsummaryrefslogtreecommitdiffstats
path: root/src/main/java/eu/siacs/conversations/utils/DNSHelper.java
blob: a8aba6db6b26634e02b44e3a15084904a7afa2fe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
package eu.siacs.conversations.utils;

import android.annotation.TargetApi;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.LinkProperties;
import android.net.Network;
import android.net.RouteInfo;
import android.os.Build;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;

import java.io.IOException;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.SocketTimeoutException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.Random;
import java.util.TreeMap;
import java.util.Map;
import java.util.regex.Pattern;

import de.measite.minidns.Client;
import de.measite.minidns.DNSMessage;
import de.measite.minidns.Record;
import de.measite.minidns.Record.CLASS;
import de.measite.minidns.Record.TYPE;
import de.measite.minidns.record.A;
import de.measite.minidns.record.AAAA;
import de.measite.minidns.record.Data;
import de.measite.minidns.record.SRV;
import de.measite.minidns.util.NameUtil;
import eu.siacs.conversations.Config;
import eu.siacs.conversations.xmpp.jid.Jid;

public class DNSHelper {

	public static final Pattern PATTERN_IPV4 = Pattern.compile("\\A(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
	public static final Pattern PATTERN_IPV6_HEX4DECCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?) ::((?:[0-9A-Fa-f]{1,4}:)*)(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
	public static final Pattern PATTERN_IPV6_6HEX4DEC = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}:){6,6})(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}\\z");
	public static final Pattern PATTERN_IPV6_HEXCOMPRESSED = Pattern.compile("\\A((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)::((?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?)\\z");
	public static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");

	protected static Client client = new Client();

	protected static Context context;

	public static Bundle getSRVRecord(final Jid jid, Context context) throws IOException {
		DNSHelper.context = context;
        final String host = jid.getDomainpart();
		final List<InetAddress> servers = Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP ? getDnsServers(context) : getDnsServersPreLollipop();
		Bundle b = new Bundle();
		boolean interrupted = false;
		for(InetAddress server : servers) {
			if (Thread.currentThread().isInterrupted()) {
				interrupted = true;
				break;
			}
			b = queryDNS(host, server);
			if (b.containsKey("values")) {
				return b;
			}
		}
		if (!b.containsKey("values")) {
			Log.d(Config.LOGTAG,(interrupted ? "Thread interrupted during DNS query" :"all dns queries failed") + ". provide fallback A record");
			ArrayList<Parcelable> values = new ArrayList<>();
			values.add(createNamePortBundle(host, 5222, false));
			b.putParcelableArrayList("values",values);
		}
		return b;
	}

	@TargetApi(21)
	private static List<InetAddress> getDnsServers(Context context) {
		List<InetAddress> servers = new ArrayList<>();
		ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
		Network[] networks = connectivityManager == null ? null : connectivityManager.getAllNetworks();
		if (networks == null) {
			return getDnsServersPreLollipop();
		}
		for(int i = 0; i < networks.length; ++i) {
			LinkProperties linkProperties = connectivityManager.getLinkProperties(networks[i]);
			if (linkProperties != null) {
				if (hasDefaultRoute(linkProperties)) {
					servers.addAll(0, getIPv4First(linkProperties.getDnsServers()));
				} else {
					servers.addAll(getIPv4First(linkProperties.getDnsServers()));
				}
			}
		}
		if (servers.size() > 0) {
			Log.d(Config.LOGTAG, "used lollipop variant to discover dns servers in " + networks.length + " networks");
		}
		return servers.size() > 0 ? servers : getDnsServersPreLollipop();
	}

	private static List<InetAddress> getIPv4First(List<InetAddress> in) {
		List<InetAddress> out = new ArrayList<>();
		for(InetAddress addr : in) {
			if (addr instanceof Inet4Address) {
				out.add(0, addr);
			} else {
				out.add(addr);
			}
		}
		return out;
	}

	@TargetApi(Build.VERSION_CODES.LOLLIPOP)
	private static boolean hasDefaultRoute(LinkProperties linkProperties) {
		for(RouteInfo route: linkProperties.getRoutes()) {
			if (route.isDefaultRoute()) {
				return true;
			}
		}
		return false;
	}

	private static List<InetAddress> getDnsServersPreLollipop() {
		List<InetAddress> servers = new ArrayList<>();
		String[] dns = client.findDNS();
		for(int i = 0; i < dns.length; ++i) {
			try {
				servers.add(InetAddress.getByName(dns[i]));
			} catch (UnknownHostException e) {
				//ignore
			}
		}
		return servers;
	}

	private static class TlsSrv {
		private final SRV srv;
		private final boolean tls;

		public TlsSrv(SRV srv, boolean tls) {
			this.srv = srv;
			this.tls = tls;
		}
	}

	private static void fillSrvMaps(final String qname, final InetAddress dnsServer, final Map<Integer, List<TlsSrv>> priorities, final Map<String, List<String>> ips4, final Map<String, List<String>> ips6, final boolean tls) throws IOException {
		final DNSMessage message = client.query(qname, TYPE.SRV, CLASS.IN, dnsServer.getHostAddress());
		for (Record[] rrset : new Record[][] { message.getAnswers(), message.getAdditionalResourceRecords() }) {
			for (Record rr : rrset) {
				Data d = rr.getPayload();
				final String name = rr.getName() != null ? rr.getName().toLowerCase(Locale.US) : null;
				if (d instanceof SRV && NameUtil.idnEquals(qname, name)) {
					SRV srv = (SRV) d;
					if (!priorities.containsKey(srv.getPriority())) {
						priorities.put(srv.getPriority(),new ArrayList<TlsSrv>());
					}
					priorities.get(srv.getPriority()).add(new TlsSrv(srv, tls));
				} else if (d instanceof SRV) {
					Log.d(Config.LOGTAG,"found unrecognized SRV record with name: "+name);
				}
				if (d instanceof A) {
					A a = (A) d;
					if (!ips4.containsKey(name)) {
						ips4.put(name, new ArrayList<String>());
					}
					ips4.get(name).add(a.toString());
				}
				if (d instanceof AAAA) {
					AAAA aaaa = (AAAA) d;
					if (!ips6.containsKey(name)) {
						ips6.put(name, new ArrayList<String>());
					}
					ips6.get(name).add("[" + aaaa.toString() + "]");
				}
			}
		}
	}

	public static Bundle queryDNS(String host, InetAddress dnsServer) {
		Bundle bundle = new Bundle();
		try {
			client.setTimeout(Config.SOCKET_TIMEOUT * 1000);
			final String qname = "_xmpp-client._tcp." + host.toLowerCase(Locale.US);
			final String tlsQname = "_xmpps-client._tcp." + host.toLowerCase(Locale.US);
			Log.d(Config.LOGTAG, "using dns server: " + dnsServer.getHostAddress() + " to look up " + host);

			final Map<Integer, List<TlsSrv>> priorities = new TreeMap<>();
			final Map<String, List<String>> ips4 = new TreeMap<>();
			final Map<String, List<String>> ips6 = new TreeMap<>();

			fillSrvMaps(qname, dnsServer, priorities, ips4, ips6, false);
			fillSrvMaps(tlsQname, dnsServer, priorities, ips4, ips6, true);

			final List<TlsSrv> result = new ArrayList<>();
			for (final List<TlsSrv> s : priorities.values()) {
				result.addAll(s);
			}

			final ArrayList<Bundle> values = new ArrayList<>();
			if (result.size() == 0) {
				DNSMessage response;
				try {
					response = client.query(host, TYPE.A, CLASS.IN, dnsServer.getHostAddress());
					for (int i = 0; i < response.getAnswers().length; ++i) {
						values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
					}
				} catch (SocketTimeoutException e) {
					Log.d(Config.LOGTAG,"ignoring timeout exception when querying A record on "+dnsServer.getHostAddress());
				}
				try {
					response = client.query(host, TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
					for (int i = 0; i < response.getAnswers().length; ++i) {
						values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
					}
				} catch (SocketTimeoutException e) {
					Log.d(Config.LOGTAG,"ignoring timeout exception when querying AAAA record on "+dnsServer.getHostAddress());
				}
				values.add(createNamePortBundle(host, 5222, false));
				bundle.putParcelableArrayList("values", values);
				return bundle;
			}
			for (final TlsSrv tlsSrv : result) {
				final SRV srv = tlsSrv.srv;
				final String name = srv.getName() != null ? srv.getName().toLowerCase(Locale.US) : null;
				if (ips6.containsKey(name)) {
					values.add(createNamePortBundle(name,srv.getPort(),ips6, tlsSrv.tls));
				} else {
					try {
						DNSMessage response = client.query(name, TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
						for (int i = 0; i < response.getAnswers().length; ++i) {
							values.add(createNamePortBundle(name, srv.getPort(), response.getAnswers()[i].getPayload(), tlsSrv.tls));
						}
					} catch (SocketTimeoutException e) {
						Log.d(Config.LOGTAG,"ignoring timeout exception when querying AAAA record on "+dnsServer.getHostAddress());
					}
				}
				if (ips4.containsKey(name)) {
					values.add(createNamePortBundle(name,srv.getPort(),ips4, tlsSrv.tls));
				} else {
					DNSMessage response = client.query(name, TYPE.A, CLASS.IN, dnsServer.getHostAddress());
					for(int i = 0; i < response.getAnswers().length; ++i) {
						values.add(createNamePortBundle(name,srv.getPort(),response.getAnswers()[i].getPayload(), tlsSrv.tls));
					}
				}
				values.add(createNamePortBundle(name, srv.getPort(), tlsSrv.tls));
			}
			bundle.putParcelableArrayList("values", values);
		} catch (SocketTimeoutException e) {
			bundle.putString("error", "timeout");
		} catch (Exception e) {
			bundle.putString("error", "unhandled");
		}
		return bundle;
	}

	private static Bundle createNamePortBundle(String name, int port, final boolean tls) {
		Bundle namePort = new Bundle();
		namePort.putString("name", name);
		namePort.putBoolean("tls", tls);
		namePort.putInt("port", port);
		return namePort;
	}

	private static Bundle createNamePortBundle(String name, int port, Map<String, List<String>> ips, final boolean tls) {
		Bundle namePort = new Bundle();
		namePort.putString("name", name);
		namePort.putBoolean("tls", tls);
		namePort.putInt("port", port);
		if (ips!=null) {
			List<String> ip = ips.get(name);
			Collections.shuffle(ip, new Random());
			namePort.putString("ip", ip.get(0));
		}
		return namePort;
	}

	private static Bundle createNamePortBundle(String name, int port, Data data, final boolean tls) {
		Bundle namePort = new Bundle();
		namePort.putString("name", name);
		namePort.putBoolean("tls", tls);
		namePort.putInt("port", port);
		if (data instanceof A) {
			namePort.putString("ip", data.toString());
		} else if (data instanceof AAAA) {
			namePort.putString("ip","["+data.toString()+"]");
		}
		return namePort;
	}

	public static boolean isIp(final String server) {
		return server != null && (
				PATTERN_IPV4.matcher(server).matches()
				|| PATTERN_IPV6.matcher(server).matches()
				|| PATTERN_IPV6_6HEX4DEC.matcher(server).matches()
				|| PATTERN_IPV6_HEX4DECCOMPRESSED.matcher(server).matches()
				|| PATTERN_IPV6_HEXCOMPRESSED.matcher(server).matches());
	}
}