diff options
Diffstat (limited to 'src/main/java/eu/siacs/conversations/utils/DNSHelper.java')
-rw-r--r-- | src/main/java/eu/siacs/conversations/utils/DNSHelper.java | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/src/main/java/eu/siacs/conversations/utils/DNSHelper.java b/src/main/java/eu/siacs/conversations/utils/DNSHelper.java new file mode 100644 index 00000000..79a8c854 --- /dev/null +++ b/src/main/java/eu/siacs/conversations/utils/DNSHelper.java @@ -0,0 +1,103 @@ +package eu.siacs.conversations.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 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 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<SrvRecord> querySrvRecord(Jid jid) { + String host = jid.getDomainpart(); + String dns[] = client.findDNS(); + TreeSet<SrvRecord> 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<SrvRecord> querySrvRecord(String host, String dnsserver) { + TreeSet<SrvRecord> 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: + * <ul> + * <li>{@link #PATTERN_IPV4}</li> + * <li>{@link #PATTERN_IPV6}</li> + * <li>{@link #PATTERN_IPV6_6HEX4DEC}</li> + * <li>{@link #PATTERN_IPV6_HEX4DECCOMPRESSED}</li> + * <li>{@link #PATTERN_IPV6_HEXCOMPRESSED}</li> + * </ul> + * @param server the string to check + * @return <code>true</code> if one of the patterns is matched <code>false</code> 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(); + } +} |