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