1package eu.siacs.conversations.utils;
2
3import android.annotation.TargetApi;
4import android.content.Context;
5import android.net.ConnectivityManager;
6import android.net.LinkProperties;
7import android.net.Network;
8import android.net.RouteInfo;
9import android.os.Build;
10import android.os.Bundle;
11import android.os.Parcelable;
12import android.util.Log;
13
14import java.io.IOException;
15import java.net.Inet4Address;
16import java.net.InetAddress;
17import java.net.SocketTimeoutException;
18import java.net.UnknownHostException;
19import java.util.ArrayList;
20import java.util.Collections;
21import java.util.List;
22import java.util.Locale;
23import java.util.Random;
24import java.util.TreeMap;
25import java.util.Map;
26import java.util.regex.Pattern;
27
28import de.measite.minidns.Client;
29import de.measite.minidns.DNSMessage;
30import de.measite.minidns.Record;
31import de.measite.minidns.Record.CLASS;
32import de.measite.minidns.Record.TYPE;
33import de.measite.minidns.record.A;
34import de.measite.minidns.record.AAAA;
35import de.measite.minidns.record.Data;
36import de.measite.minidns.record.SRV;
37import de.measite.minidns.util.NameUtil;
38import eu.siacs.conversations.Config;
39import eu.siacs.conversations.xmpp.jid.Jid;
40
41public class DNSHelper {
42
43 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");
44 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");
45 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");
46 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");
47 public static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");
48
49 protected static Client client = new Client();
50
51 protected static Context context;
52
53 public static Bundle getSRVRecord(final Jid jid, Context context) throws IOException {
54 DNSHelper.context = context;
55 final String host = jid.getDomainpart();
56 final List<InetAddress> servers = Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP ? getDnsServers(context) : getDnsServersPreLollipop();
57 Bundle b = new Bundle();
58 boolean interrupted = false;
59 for(InetAddress server : servers) {
60 if (Thread.currentThread().isInterrupted()) {
61 interrupted = true;
62 break;
63 }
64 b = queryDNS(host, server);
65 if (b.containsKey("values")) {
66 return b;
67 }
68 }
69 if (!b.containsKey("values")) {
70 Log.d(Config.LOGTAG,(interrupted ? "Thread interrupted during DNS query" :"all dns queries failed") + ". provide fallback A record");
71 ArrayList<Parcelable> values = new ArrayList<>();
72 values.add(createNamePortBundle(host, 5222, false));
73 b.putParcelableArrayList("values",values);
74 }
75 return b;
76 }
77
78 @TargetApi(21)
79 private static List<InetAddress> getDnsServers(Context context) {
80 List<InetAddress> servers = new ArrayList<>();
81 ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
82 Network[] networks = connectivityManager == null ? null : connectivityManager.getAllNetworks();
83 if (networks == null) {
84 return getDnsServersPreLollipop();
85 }
86 for(int i = 0; i < networks.length; ++i) {
87 LinkProperties linkProperties = connectivityManager.getLinkProperties(networks[i]);
88 if (linkProperties != null) {
89 if (hasDefaultRoute(linkProperties)) {
90 servers.addAll(0, getIPv4First(linkProperties.getDnsServers()));
91 } else {
92 servers.addAll(getIPv4First(linkProperties.getDnsServers()));
93 }
94 }
95 }
96 if (servers.size() > 0) {
97 Log.d(Config.LOGTAG, "used lollipop variant to discover dns servers in " + networks.length + " networks");
98 }
99 return servers.size() > 0 ? servers : getDnsServersPreLollipop();
100 }
101
102 private static List<InetAddress> getIPv4First(List<InetAddress> in) {
103 List<InetAddress> out = new ArrayList<>();
104 for(InetAddress addr : in) {
105 if (addr instanceof Inet4Address) {
106 out.add(0, addr);
107 } else {
108 out.add(addr);
109 }
110 }
111 return out;
112 }
113
114 @TargetApi(Build.VERSION_CODES.LOLLIPOP)
115 private static boolean hasDefaultRoute(LinkProperties linkProperties) {
116 for(RouteInfo route: linkProperties.getRoutes()) {
117 if (route.isDefaultRoute()) {
118 return true;
119 }
120 }
121 return false;
122 }
123
124 private static List<InetAddress> getDnsServersPreLollipop() {
125 List<InetAddress> servers = new ArrayList<>();
126 String[] dns = client.findDNS();
127 for(int i = 0; i < dns.length; ++i) {
128 try {
129 servers.add(InetAddress.getByName(dns[i]));
130 } catch (UnknownHostException e) {
131 //ignore
132 }
133 }
134 return servers;
135 }
136
137 private static class TlsSrv {
138 private final SRV srv;
139 private final boolean tls;
140
141 public TlsSrv(SRV srv, boolean tls) {
142 this.srv = srv;
143 this.tls = tls;
144 }
145 }
146
147 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 {
148 final DNSMessage message = client.query(qname, TYPE.SRV, CLASS.IN, dnsServer.getHostAddress());
149 for (Record[] rrset : new Record[][] { message.getAnswers(), message.getAdditionalResourceRecords() }) {
150 for (Record rr : rrset) {
151 Data d = rr.getPayload();
152 final String name = rr.getName() != null ? rr.getName().toLowerCase(Locale.US) : null;
153 if (d instanceof SRV && NameUtil.idnEquals(qname, name)) {
154 SRV srv = (SRV) d;
155 if (!priorities.containsKey(srv.getPriority())) {
156 priorities.put(srv.getPriority(),new ArrayList<TlsSrv>());
157 }
158 priorities.get(srv.getPriority()).add(new TlsSrv(srv, tls));
159 } else if (d instanceof SRV) {
160 Log.d(Config.LOGTAG,"found unrecognized SRV record with name: "+name);
161 }
162 if (d instanceof A) {
163 A a = (A) d;
164 if (!ips4.containsKey(name)) {
165 ips4.put(name, new ArrayList<String>());
166 }
167 ips4.get(name).add(a.toString());
168 }
169 if (d instanceof AAAA) {
170 AAAA aaaa = (AAAA) d;
171 if (!ips6.containsKey(name)) {
172 ips6.put(name, new ArrayList<String>());
173 }
174 ips6.get(name).add("[" + aaaa.toString() + "]");
175 }
176 }
177 }
178 }
179
180 public static Bundle queryDNS(String host, InetAddress dnsServer) {
181 Bundle bundle = new Bundle();
182 try {
183 client.setTimeout(Config.SOCKET_TIMEOUT * 1000);
184 final String qname = "_xmpp-client._tcp." + host.toLowerCase(Locale.US);
185 final String tlsQname = "_xmpps-client._tcp." + host.toLowerCase(Locale.US);
186 Log.d(Config.LOGTAG, "using dns server: " + dnsServer.getHostAddress() + " to look up " + host);
187
188 final Map<Integer, List<TlsSrv>> priorities = new TreeMap<>();
189 final Map<String, List<String>> ips4 = new TreeMap<>();
190 final Map<String, List<String>> ips6 = new TreeMap<>();
191
192 fillSrvMaps(qname, dnsServer, priorities, ips4, ips6, false);
193 fillSrvMaps(tlsQname, dnsServer, priorities, ips4, ips6, true);
194
195 final List<TlsSrv> result = new ArrayList<>();
196 for (final List<TlsSrv> s : priorities.values()) {
197 result.addAll(s);
198 }
199
200 final ArrayList<Bundle> values = new ArrayList<>();
201 if (result.size() == 0) {
202 DNSMessage response;
203 try {
204 response = client.query(host, TYPE.A, CLASS.IN, dnsServer.getHostAddress());
205 for (int i = 0; i < response.getAnswers().length; ++i) {
206 values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
207 }
208 } catch (SocketTimeoutException e) {
209 Log.d(Config.LOGTAG,"ignoring timeout exception when querying A record on "+dnsServer.getHostAddress());
210 }
211 try {
212 response = client.query(host, TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
213 for (int i = 0; i < response.getAnswers().length; ++i) {
214 values.add(createNamePortBundle(host, 5222, response.getAnswers()[i].getPayload(), false));
215 }
216 } catch (SocketTimeoutException e) {
217 Log.d(Config.LOGTAG,"ignoring timeout exception when querying AAAA record on "+dnsServer.getHostAddress());
218 }
219 values.add(createNamePortBundle(host, 5222, false));
220 bundle.putParcelableArrayList("values", values);
221 return bundle;
222 }
223 for (final TlsSrv tlsSrv : result) {
224 final SRV srv = tlsSrv.srv;
225 final String name = srv.getName() != null ? srv.getName().toLowerCase(Locale.US) : null;
226 if (ips6.containsKey(name)) {
227 values.add(createNamePortBundle(name,srv.getPort(),ips6, tlsSrv.tls));
228 } else {
229 try {
230 DNSMessage response = client.query(name, TYPE.AAAA, CLASS.IN, dnsServer.getHostAddress());
231 for (int i = 0; i < response.getAnswers().length; ++i) {
232 values.add(createNamePortBundle(name, srv.getPort(), response.getAnswers()[i].getPayload(), tlsSrv.tls));
233 }
234 } catch (SocketTimeoutException e) {
235 Log.d(Config.LOGTAG,"ignoring timeout exception when querying AAAA record on "+dnsServer.getHostAddress());
236 }
237 }
238 if (ips4.containsKey(name)) {
239 values.add(createNamePortBundle(name,srv.getPort(),ips4, tlsSrv.tls));
240 } else {
241 DNSMessage response = client.query(name, TYPE.A, CLASS.IN, dnsServer.getHostAddress());
242 for(int i = 0; i < response.getAnswers().length; ++i) {
243 values.add(createNamePortBundle(name,srv.getPort(),response.getAnswers()[i].getPayload(), tlsSrv.tls));
244 }
245 }
246 values.add(createNamePortBundle(name, srv.getPort(), tlsSrv.tls));
247 }
248 bundle.putParcelableArrayList("values", values);
249 } catch (SocketTimeoutException e) {
250 bundle.putString("error", "timeout");
251 } catch (Exception e) {
252 bundle.putString("error", "unhandled");
253 }
254 return bundle;
255 }
256
257 private static Bundle createNamePortBundle(String name, int port, final boolean tls) {
258 Bundle namePort = new Bundle();
259 namePort.putString("name", name);
260 namePort.putBoolean("tls", tls);
261 namePort.putInt("port", port);
262 return namePort;
263 }
264
265 private static Bundle createNamePortBundle(String name, int port, Map<String, List<String>> ips, final boolean tls) {
266 Bundle namePort = new Bundle();
267 namePort.putString("name", name);
268 namePort.putBoolean("tls", tls);
269 namePort.putInt("port", port);
270 if (ips!=null) {
271 List<String> ip = ips.get(name);
272 Collections.shuffle(ip, new Random());
273 namePort.putString("ip", ip.get(0));
274 }
275 return namePort;
276 }
277
278 private static Bundle createNamePortBundle(String name, int port, Data data, final boolean tls) {
279 Bundle namePort = new Bundle();
280 namePort.putString("name", name);
281 namePort.putBoolean("tls", tls);
282 namePort.putInt("port", port);
283 if (data instanceof A) {
284 namePort.putString("ip", data.toString());
285 } else if (data instanceof AAAA) {
286 namePort.putString("ip","["+data.toString()+"]");
287 }
288 return namePort;
289 }
290
291 public static boolean isIp(final String server) {
292 return server != null && (
293 PATTERN_IPV4.matcher(server).matches()
294 || PATTERN_IPV6.matcher(server).matches()
295 || PATTERN_IPV6_6HEX4DEC.matcher(server).matches()
296 || PATTERN_IPV6_HEX4DECCOMPRESSED.matcher(server).matches()
297 || PATTERN_IPV6_HEXCOMPRESSED.matcher(server).matches());
298 }
299}