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Diffstat (limited to 'src/main/java/eu/siacs/conversations/utils/DNSHelper.java')
-rw-r--r--src/main/java/eu/siacs/conversations/utils/DNSHelper.java165
1 files changed, 165 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..9caa53f7
--- /dev/null
+++ b/src/main/java/eu/siacs/conversations/utils/DNSHelper.java
@@ -0,0 +1,165 @@
+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);
+ if (null != message) {
+ 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);
+ }
+ }
+ } else {
+ Logging.e("dns", "No valid DNS message retrieved.");
+ }
+
+ } 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());
+ }
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-18 11:40:12 +0000