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