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package eu.siacs.conversations.utils;
import android.annotation.TargetApi;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.LinkProperties;
import android.net.Network;
import android.net.RouteInfo;
import android.os.Build;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import java.util.TreeSet;
import java.util.regex.Pattern;
import de.measite.minidns.Client;
import de.measite.minidns.DNSMessage;
import de.measite.minidns.Record;
import de.measite.minidns.Record.CLASS;
import de.measite.minidns.Record.TYPE;
import de.measite.minidns.record.Data;
import de.measite.minidns.record.SRV;
import de.measite.minidns.util.NameUtil;
import de.thedevstack.android.logcat.Logging;
import de.thedevstack.conversationsplus.ConversationsPlusApplication;
import de.thedevstack.conversationsplus.dto.SrvRecord;
import eu.siacs.conversations.Config;
import eu.siacs.conversations.xmpp.jid.Jid;
public class DNSHelper {
private static final String CLIENT_SRV_PREFIX = "_xmpp-client._tcp.";
private static final String SECURE_CLIENT_SRV_PREFIX = "_xmpps-client._tcp.";
private 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");
private 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");
private 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");
private 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");
private static final Pattern PATTERN_IPV6 = Pattern.compile("\\A(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}\\z");
protected static Client client = new Client();
static {
client.setTimeout(Config.PING_TIMEOUT * 1000);
}
/**
* Queries the SRV record for the server JID.
* This method uses all available Domain Name Servers.
* @param jid the server JID
* @return TreeSet with SrvRecords. If no SRV record is found for JID an empty TreeSet is returned.
*/
public static final TreeSet<SrvRecord> querySrvRecord(Jid jid) {
String host = jid.getDomainpart();
TreeSet<SrvRecord> result = new TreeSet<>();
final List<InetAddress> dnsServers = Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP ? getDnsServers() : getDnsServersPreLollipop();
if (dnsServers != null) {
for (InetAddress dnsServer : dnsServers) {
result = querySrvRecord(host, dnsServer);
if (!result.isEmpty()) {
break;
}
}
}
return result;
}
@TargetApi(21)
private static List<InetAddress> getDnsServers() {
List<InetAddress> servers = new ArrayList<>();
ConnectivityManager connectivityManager = (ConnectivityManager) ConversationsPlusApplication.getInstance().getSystemService(Context.CONNECTIVITY_SERVICE);
Network[] networks = connectivityManager == null ? null : connectivityManager.getAllNetworks();
if (networks == null) {
return getDnsServersPreLollipop();
}
for(int i = 0; i < networks.length; ++i) {
LinkProperties linkProperties = connectivityManager.getLinkProperties(networks[i]);
if (linkProperties != null) {
if (hasDefaultRoute(linkProperties)) {
servers.addAll(0, linkProperties.getDnsServers());
} else {
servers.addAll(linkProperties.getDnsServers());
}
}
}
if (servers.size() > 0) {
Logging.d("dns", "used lollipop variant to discover dns servers in " + networks.length + " networks");
}
return servers.size() > 0 ? servers : getDnsServersPreLollipop();
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
private static boolean hasDefaultRoute(LinkProperties linkProperties) {
for(RouteInfo route: linkProperties.getRoutes()) {
if (route.isDefaultRoute()) {
return true;
}
}
return false;
}
private static List<InetAddress> getDnsServersPreLollipop() {
List<InetAddress> servers = new ArrayList<>();
String[] dns = client.findDNS();
for(int i = 0; i < dns.length; ++i) {
try {
servers.add(InetAddress.getByName(dns[i]));
} catch (UnknownHostException e) {
//ignore
}
}
return servers;
}
/**
* Queries the SRV record for an host from the given Domain Name Server.
* @param host the host to query for
* @param dnsServerAddress the DNS to query on
* @return TreeSet with SrvRecords.
*/
private static final TreeSet<SrvRecord> querySrvRecord(String host, InetAddress dnsServerAddress) {
TreeSet<SrvRecord> result = new TreeSet<>();
querySrvRecord(host, dnsServerAddress, false, result);
querySrvRecord(host, dnsServerAddress, true, result);
return result;
}
private static final void querySrvRecord(String host, InetAddress dnsServerAddress, boolean tlsSrvRecord, TreeSet<SrvRecord> result) {
String qname = (tlsSrvRecord ? SECURE_CLIENT_SRV_PREFIX : CLIENT_SRV_PREFIX) + host;
String dnsServerHostAddress = dnsServerAddress.getHostAddress();
Logging.d("dns", "using dns server: " + dnsServerHostAddress + " to look up " + qname);
try {
DNSMessage message = client.query(qname, TYPE.SRV, CLASS.IN, dnsServerHostAddress);
Record[] rrset = message.getAnswers();
for (Record rr : rrset) {
Data d = rr.getPayload();
if (d instanceof SRV && NameUtil.idnEquals(qname, rr.getName())) {
SRV srv = (SRV) d;
SrvRecord srvRecord = new SrvRecord(srv.getPriority(), srv.getName(), srv.getPort(), tlsSrvRecord);
result.add(srvRecord);
}
}
} catch (IOException e) {
Logging.d("dns", "Error while retrieving SRV record '" + qname + "' for '" + host + "' from DNS '" + dnsServerHostAddress + "': " + e.getMessage());
}
}
public static boolean isIp(final String server) {
return server != null && (
PATTERN_IPV4.matcher(server).matches()
|| PATTERN_IPV6.matcher(server).matches()
|| PATTERN_IPV6_6HEX4DEC.matcher(server).matches()
|| PATTERN_IPV6_HEX4DECCOMPRESSED.matcher(server).matches()
|| PATTERN_IPV6_HEXCOMPRESSED.matcher(server).matches());
}
}
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