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