1package eu.siacs.conversations.utils;
2
3import android.content.ContentValues;
4import android.database.Cursor;
5import android.util.Log;
6
7import androidx.annotation.NonNull;
8
9import com.google.common.base.Strings;
10import com.google.common.base.Throwables;
11import com.google.common.net.InetAddresses;
12import com.google.common.primitives.Ints;
13
14import java.io.IOException;
15import java.lang.reflect.Field;
16import java.net.Inet4Address;
17import java.net.InetAddress;
18import java.net.UnknownHostException;
19import java.util.ArrayList;
20import java.util.Collections;
21import java.util.List;
22
23//import de.gultsch.minidns.AndroidDNSClient;
24import org.minidns.AbstractDnsClient;
25import org.minidns.DnsCache;
26import org.minidns.DnsClient;
27import org.minidns.dnsname.DnsName;
28import org.minidns.dnsmessage.Question;
29import org.minidns.record.Record;
30import org.minidns.cache.LruCache;
31import org.minidns.dnssec.DnssecResultNotAuthenticException;
32import org.minidns.dnsserverlookup.AndroidUsingExec;
33import org.minidns.hla.DnssecResolverApi;
34import org.minidns.hla.ResolverApi;
35import org.minidns.hla.ResolverResult;
36import org.minidns.iterative.ReliableDnsClient;
37import org.minidns.record.A;
38import org.minidns.record.AAAA;
39import org.minidns.record.CNAME;
40import org.minidns.record.Data;
41import org.minidns.record.InternetAddressRR;
42import org.minidns.record.SRV;
43import eu.siacs.conversations.Config;
44import eu.siacs.conversations.R;
45import eu.siacs.conversations.services.XmppConnectionService;
46import eu.siacs.conversations.xmpp.Jid;
47
48public class Resolver {
49
50 public static final int DEFAULT_PORT_XMPP = 5222;
51
52 private static final String DIRECT_TLS_SERVICE = "_xmpps-client";
53 private static final String STARTTLS_SERVICE = "_xmpp-client";
54
55 private static XmppConnectionService SERVICE = null;
56
57
58 public static void init(XmppConnectionService service) {
59 Resolver.SERVICE = service;
60 DnsClient.removeDNSServerLookupMechanism(AndroidUsingExec.INSTANCE);
61 DnsClient.addDnsServerLookupMechanism(AndroidUsingExecLowPriority.INSTANCE);
62 DnsClient.addDnsServerLookupMechanism(new AndroidUsingLinkProperties(service));
63 final AbstractDnsClient client = ResolverApi.INSTANCE.getClient();
64 if (client instanceof ReliableDnsClient) {
65 ((ReliableDnsClient) client).setUseHardcodedDnsServers(false);
66 }
67 }
68
69 public static List<Result> fromHardCoded(final String hostname, final int port) {
70 final Result result = new Result();
71 result.hostname = DnsName.from(hostname);
72 result.port = port;
73 result.directTls = useDirectTls(port);
74 result.authenticated = true;
75 return Collections.singletonList(result);
76 }
77
78 public static void checkDomain(final Jid jid) {
79 DnsName.from(jid.getDomain());
80 }
81
82 public static boolean invalidHostname(final String hostname) {
83 try {
84 DnsName.from(hostname);
85 return false;
86 } catch (IllegalArgumentException e) {
87 return true;
88 }
89 }
90
91 public static void clearCache() {
92 final AbstractDnsClient client = ResolverApi.INSTANCE.getClient();
93 final DnsCache dnsCache = client.getCache();
94 if (dnsCache instanceof LruCache) {
95 Log.d(Config.LOGTAG,"clearing DNS cache");
96 ((LruCache) dnsCache).clear();
97 }
98 }
99
100
101 public static boolean useDirectTls(final int port) {
102 return port == 443 || port == 5223;
103 }
104
105 public static List<Result> resolve(final String domain) {
106 final List<Result> ipResults = fromIpAddress(domain);
107 if (ipResults.size() > 0) {
108 return ipResults;
109 }
110 final List<Result> results = new ArrayList<>();
111 final List<Result> fallbackResults = new ArrayList<>();
112 final Thread[] threads = new Thread[3];
113 threads[0] = new Thread(() -> {
114 try {
115 final List<Result> list = resolveSrv(domain, true);
116 synchronized (results) {
117 results.addAll(list);
118 }
119 } catch (final Throwable throwable) {
120 if (!(Throwables.getRootCause(throwable) instanceof InterruptedException)) {
121 Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving SRV record (direct TLS)", throwable);
122 }
123 }
124 });
125 threads[1] = new Thread(() -> {
126 try {
127 final List<Result> list = resolveSrv(domain, false);
128 synchronized (results) {
129 results.addAll(list);
130 }
131 } catch (final Throwable throwable) {
132 if (!(Throwables.getRootCause(throwable) instanceof InterruptedException)) {
133 Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving SRV record (STARTTLS)", throwable);
134 }
135 }
136 });
137 threads[2] = new Thread(() -> {
138 List<Result> list = resolveNoSrvRecords(DnsName.from(domain), true);
139 synchronized (fallbackResults) {
140 fallbackResults.addAll(list);
141 }
142 });
143 for (final Thread thread : threads) {
144 thread.start();
145 }
146 try {
147 threads[0].join();
148 threads[1].join();
149 if (results.size() > 0) {
150 threads[2].interrupt();
151 synchronized (results) {
152 Collections.sort(results);
153 Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": " + results.toString());
154 return new ArrayList<>(results);
155 }
156 } else {
157 threads[2].join();
158 synchronized (fallbackResults) {
159 Collections.sort(fallbackResults);
160 Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": " + fallbackResults.toString());
161 return new ArrayList<>(fallbackResults);
162 }
163 }
164 } catch (InterruptedException e) {
165 for (Thread thread : threads) {
166 thread.interrupt();
167 }
168 return Collections.emptyList();
169 }
170 }
171
172 private static List<Result> fromIpAddress(String domain) {
173 if (!IP.matches(domain)) {
174 return Collections.emptyList();
175 }
176 try {
177 Result result = new Result();
178 result.ip = InetAddress.getByName(domain);
179 result.port = DEFAULT_PORT_XMPP;
180 result.authenticated = true;
181 return Collections.singletonList(result);
182 } catch (UnknownHostException e) {
183 return Collections.emptyList();
184 }
185 }
186
187 private static List<Result> resolveSrv(String domain, final boolean directTls) throws IOException {
188 DnsName dnsName = DnsName.from((directTls ? DIRECT_TLS_SERVICE : STARTTLS_SERVICE) + "._tcp." + domain);
189 ResolverResult<SRV> result = resolveWithFallback(dnsName, SRV.class);
190 final List<Result> results = new ArrayList<>();
191 final List<Thread> threads = new ArrayList<>();
192 for (SRV record : result.getAnswersOrEmptySet()) {
193 if (record.name.length() == 0 && record.priority == 0) {
194 continue;
195 }
196 threads.add(new Thread(() -> {
197 final List<Result> ipv4s = resolveIp(record, A.class, result.isAuthenticData(), directTls);
198 if (ipv4s.size() == 0) {
199 Result resolverResult = Result.fromRecord(record, directTls);
200 resolverResult.authenticated = result.isAuthenticData();
201 ipv4s.add(resolverResult);
202 }
203 synchronized (results) {
204 results.addAll(ipv4s);
205 }
206
207 }));
208 threads.add(new Thread(() -> {
209 final List<Result> ipv6s = resolveIp(record, AAAA.class, result.isAuthenticData(), directTls);
210 synchronized (results) {
211 results.addAll(ipv6s);
212 }
213 }));
214 }
215 for (Thread thread : threads) {
216 thread.start();
217 }
218 for (Thread thread : threads) {
219 try {
220 thread.join();
221 } catch (InterruptedException e) {
222 return Collections.emptyList();
223 }
224 }
225 return results;
226 }
227
228 private static <D extends InternetAddressRR> List<Result> resolveIp(SRV srv, Class<D> type, boolean authenticated, boolean directTls) {
229 List<Result> list = new ArrayList<>();
230 try {
231 ResolverResult<D> results = resolveWithFallback(srv.name, type);
232 for (D record : results.getAnswersOrEmptySet()) {
233 Result resolverResult = Result.fromRecord(srv, directTls);
234 resolverResult.authenticated = results.isAuthenticData() && authenticated;
235 resolverResult.ip = record.getInetAddress();
236 list.add(resolverResult);
237 }
238 } catch (Throwable t) {
239 Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving " + type.getSimpleName() + " " + t.getMessage());
240 }
241 return list;
242 }
243
244 private static List<Result> resolveNoSrvRecords(DnsName dnsName, boolean withCnames) {
245 List<Result> results = new ArrayList<>();
246 try {
247 ResolverResult<A> aResult = resolveWithFallback(dnsName, A.class);
248 Log.d("WUTr", "" + aResult.isAuthenticData() + " " + aResult.getAnswersOrEmptySet());
249 for (A a : aResult.getAnswersOrEmptySet()) {
250 Result r = Result.createDefault(dnsName, a.getInetAddress());
251 r.authenticated = aResult.isAuthenticData();
252 results.add(r);
253 }
254 ResolverResult<AAAA> aaaaResult = resolveWithFallback(dnsName, AAAA.class);
255 for (AAAA aaaa : aaaaResult.getAnswersOrEmptySet()) {
256 Result r = Result.createDefault(dnsName, aaaa.getInetAddress());
257 r.authenticated = aaaaResult.isAuthenticData();
258 results.add(r);
259 }
260 if (results.size() == 0 && withCnames) {
261 ResolverResult<CNAME> cnameResult = resolveWithFallback(dnsName, CNAME.class);
262 for (CNAME cname : cnameResult.getAnswersOrEmptySet()) {
263 for (Result r : resolveNoSrvRecords(cname.name, false)) {
264 r.authenticated = r.authenticated && cnameResult.isAuthenticData();
265 results.add(r);
266 }
267 }
268 }
269 } catch (final Throwable throwable) {
270 if (!(Throwables.getRootCause(throwable) instanceof InterruptedException)) {
271 Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + "error resolving fallback records", throwable);
272 }
273 }
274 results.add(Result.createDefault(dnsName));
275 return results;
276 }
277
278 private static <D extends Data> ResolverResult<D> resolveWithFallback(DnsName dnsName, Class<D> type) throws IOException {
279 final Question question = new Question(dnsName, Record.TYPE.getType(type));
280 try {
281 return DnssecResolverApi.INSTANCE.resolve(question);
282 } catch (IOException e) {
283 throw e;
284 } catch (Throwable throwable) {
285 Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving " + type.getSimpleName() + " with DNSSEC. Trying DNS instead.", throwable);
286 }
287 return ResolverApi.INSTANCE.resolve(question);
288 }
289
290 public static class Result implements Comparable<Result> {
291 public static final String DOMAIN = "domain";
292 public static final String IP = "ip";
293 public static final String HOSTNAME = "hostname";
294 public static final String PORT = "port";
295 public static final String PRIORITY = "priority";
296 public static final String DIRECT_TLS = "directTls";
297 public static final String AUTHENTICATED = "authenticated";
298 private InetAddress ip;
299 private DnsName hostname;
300 private int port = DEFAULT_PORT_XMPP;
301 private boolean directTls = false;
302 private boolean authenticated = false;
303 private int priority;
304
305 static Result fromRecord(SRV srv, boolean directTls) {
306 Result result = new Result();
307 result.port = srv.port;
308 result.hostname = srv.name;
309 result.directTls = directTls;
310 result.priority = srv.priority;
311 return result;
312 }
313
314 static Result createDefault(DnsName hostname, InetAddress ip) {
315 Result result = new Result();
316 result.port = DEFAULT_PORT_XMPP;
317 result.hostname = hostname;
318 result.ip = ip;
319 return result;
320 }
321
322 static Result createDefault(DnsName hostname) {
323 return createDefault(hostname, null);
324 }
325
326 public static Result fromCursor(Cursor cursor) {
327 final Result result = new Result();
328 try {
329 result.ip = InetAddress.getByAddress(cursor.getBlob(cursor.getColumnIndex(IP)));
330 } catch (UnknownHostException e) {
331 result.ip = null;
332 }
333 final String hostname = cursor.getString(cursor.getColumnIndex(HOSTNAME));
334 result.hostname = hostname == null ? null : DnsName.from(hostname);
335 result.port = cursor.getInt(cursor.getColumnIndex(PORT));
336 result.priority = cursor.getInt(cursor.getColumnIndex(PRIORITY));
337 result.authenticated = cursor.getInt(cursor.getColumnIndex(AUTHENTICATED)) > 0;
338 result.directTls = cursor.getInt(cursor.getColumnIndex(DIRECT_TLS)) > 0;
339 return result;
340 }
341
342 @Override
343 public boolean equals(Object o) {
344 if (this == o) return true;
345 if (o == null || getClass() != o.getClass()) return false;
346
347 Result result = (Result) o;
348
349 if (port != result.port) return false;
350 if (directTls != result.directTls) return false;
351 if (authenticated != result.authenticated) return false;
352 if (priority != result.priority) return false;
353 if (ip != null ? !ip.equals(result.ip) : result.ip != null) return false;
354 return hostname != null ? hostname.equals(result.hostname) : result.hostname == null;
355 }
356
357 @Override
358 public int hashCode() {
359 int result = ip != null ? ip.hashCode() : 0;
360 result = 31 * result + (hostname != null ? hostname.hashCode() : 0);
361 result = 31 * result + port;
362 result = 31 * result + (directTls ? 1 : 0);
363 result = 31 * result + (authenticated ? 1 : 0);
364 result = 31 * result + priority;
365 return result;
366 }
367
368 public InetAddress getIp() {
369 return ip;
370 }
371
372 public int getPort() {
373 return port;
374 }
375
376 public DnsName getHostname() {
377 return hostname;
378 }
379
380 public boolean isDirectTls() {
381 return directTls;
382 }
383
384 public boolean isAuthenticated() {
385 return authenticated;
386 }
387
388 @Override
389 public String toString() {
390 return "Result{" +
391 "ip='" + (ip == null ? null : ip.getHostAddress()) + '\'' +
392 ", hostame='" + (hostname == null ? null : hostname.toString()) + '\'' +
393 ", port=" + port +
394 ", directTls=" + directTls +
395 ", authenticated=" + authenticated +
396 ", priority=" + priority +
397 '}';
398 }
399
400 @Override
401 public int compareTo(@NonNull Result result) {
402 if (result.priority == priority) {
403 if (directTls == result.directTls) {
404 if (ip == null && result.ip == null) {
405 return 0;
406 } else if (ip != null && result.ip != null) {
407 if (ip instanceof Inet4Address && result.ip instanceof Inet4Address) {
408 return 0;
409 } else {
410 return ip instanceof Inet4Address ? -1 : 1;
411 }
412 } else {
413 return ip != null ? -1 : 1;
414 }
415 } else {
416 return directTls ? -1 : 1;
417 }
418 } else {
419 return priority - result.priority;
420 }
421 }
422
423 public ContentValues toContentValues() {
424 final ContentValues contentValues = new ContentValues();
425 contentValues.put(IP, ip == null ? null : ip.getAddress());
426 contentValues.put(HOSTNAME, hostname == null ? null : hostname.toString());
427 contentValues.put(PORT, port);
428 contentValues.put(PRIORITY, priority);
429 contentValues.put(DIRECT_TLS, directTls ? 1 : 0);
430 contentValues.put(AUTHENTICATED, authenticated ? 1 : 0);
431 return contentValues;
432 }
433
434 public Result seeOtherHost(final String seeOtherHost) {
435 final String hostname = seeOtherHost.trim();
436 if (hostname.isEmpty()) {
437 return null;
438 }
439 final Result result = new Result();
440 result.directTls = this.directTls;
441 final int portSegmentStart = hostname.lastIndexOf(':');
442 if (hostname.charAt(hostname.length() - 1) != ']'
443 && portSegmentStart >= 0
444 && hostname.length() >= portSegmentStart + 1) {
445 final String hostPart = hostname.substring(0, portSegmentStart);
446 final String portPart = hostname.substring(portSegmentStart + 1);
447 final Integer port = Ints.tryParse(portPart);
448 if (port == null || Strings.isNullOrEmpty(hostPart)) {
449 return null;
450 }
451 final String host = eu.siacs.conversations.utils.IP.unwrapIPv6(hostPart);
452 result.port = port;
453 if (InetAddresses.isInetAddress(host)) {
454 final InetAddress inetAddress;
455 try {
456 inetAddress = InetAddresses.forString(host);
457 } catch (final IllegalArgumentException e) {
458 return null;
459 }
460 result.ip = inetAddress;
461 } else {
462 if (hostPart.trim().isEmpty()) {
463 return null;
464 }
465 try {
466 result.hostname = DnsName.from(hostPart.trim());
467 } catch (final Exception e) {
468 return null;
469 }
470 }
471 } else {
472 final String host = eu.siacs.conversations.utils.IP.unwrapIPv6(hostname);
473 if (InetAddresses.isInetAddress(host)) {
474 final InetAddress inetAddress;
475 try {
476 inetAddress = InetAddresses.forString(host);
477 } catch (final IllegalArgumentException e) {
478 return null;
479 }
480 result.ip = inetAddress;
481 } else {
482 try {
483 result.hostname = DnsName.from(hostname);
484 } catch (final Exception e) {
485 return null;
486 }
487 }
488 result.port = port;
489 }
490 return result;
491 }
492 }
493
494}