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