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