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