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 | 160 |
1 files changed, 160 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..1568eb8c --- /dev/null +++ b/src/main/java/eu/siacs/conversations/utils/DNSHelper.java @@ -0,0 +1,160 @@ +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()); + } +} |