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