package de.thedevstack.conversationsplus.utils; import de.measite.minidns.Client; import de.measite.minidns.DNSMessage; import de.measite.minidns.Record; import de.measite.minidns.Record.TYPE; import de.measite.minidns.Record.CLASS; import de.measite.minidns.record.SRV; import de.measite.minidns.record.Data; import de.measite.minidns.util.NameUtil; import java.io.IOException; import java.net.InetAddress; import java.util.TreeSet; import java.util.regex.Pattern; import de.thedevstack.android.logcat.Logging; import de.thedevstack.conversationsplus.dto.SrvRecord; import de.thedevstack.conversationsplus.xmpp.jid.Jid; public class DNSHelper { private static final String CLIENT_SRV_PREFIX = "_xmpp-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(); /** * 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 querySrvRecord(Jid jid) { String host = jid.getDomainpart(); String dns[] = client.findDNS(); TreeSet result = new TreeSet<>(); if (dns != null) { for (String dnsserver : dns) { result = querySrvRecord(host, dnsserver); if (!result.isEmpty()) { break; } } } return result; } /** * Queries the SRV record for an host from the given Domain Name Server. * @param host the host to query for * @param dnsserver the DNS to query on * @return TreeSet with SrvRecords. */ private static final TreeSet querySrvRecord(String host, String dnsserver) { TreeSet result = new TreeSet<>(); try { InetAddress dnsServerAddress = InetAddress.getByName(dnsserver); String qname = CLIENT_SRV_PREFIX + host; DNSMessage message = client.query(qname, TYPE.SRV, CLASS.IN, dnsServerAddress.getHostAddress()); 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()); result.add(srvRecord); } } } catch (IOException e) { Logging.d("dns", "Error while retrieving SRV record for '" + host + "' from DNS '" + dnsserver + "': " + e.getMessage()); } return result; } /** * Checks whether the given server is an IP address or not. * The following patterns are treated as valid IP addresses: *
    *
  • {@link #PATTERN_IPV4}
  • *
  • {@link #PATTERN_IPV6}
  • *
  • {@link #PATTERN_IPV6_6HEX4DEC}
  • *
  • {@link #PATTERN_IPV6_HEX4DECCOMPRESSED}
  • *
  • {@link #PATTERN_IPV6_HEXCOMPRESSED}
  • *
* @param server the string to check * @return true if one of the patterns is matched false otherwise */ public static boolean isIp(final String server) { return 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(); } }