1 files changed, 65 insertions, 0 deletions
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/s2s/DNSQueries.java b/juick-server/src/main/java/com/juick/server/xmpp/s2s/DNSQueries.java
new file mode 100644
index 00000000..1367d333
--- /dev/null
+++ b/juick-server/src/main/java/com/juick/server/xmpp/s2s/DNSQueries.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2008-2017, Juick
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.juick.server.xmpp.s2s;
+
+import org.apache.commons.lang3.math.NumberUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.net.InetSocketAddress;
+import java.util.Hashtable;
+import java.util.Random;
+import javax.naming.NamingException;
+import javax.naming.directory.Attribute;
+import javax.naming.directory.DirContext;
+import javax.naming.directory.InitialDirContext;
+
+/**
+ *
+ * @author ugnich
+ */
+public class DNSQueries {
+
+    private static final Logger logger = LoggerFactory.getLogger(DNSQueries.class);
+
+    private static Random rand = new Random();
+
+    public static InetSocketAddress getServerAddress(String hostname) {
+
+        String host = hostname;
+        int port = 5269;
+
+        Hashtable<String, String> env = new Hashtable<>(5);
+        env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
+        try {
+            DirContext ctx = new InitialDirContext(env);
+            Attribute att = ctx.getAttributes("_xmpp-server._tcp." + hostname, new String[]{"SRV"}).get("SRV");
+
+            if (att != null && att.size() > 0) {
+                int i = rand.nextInt(att.size());
+                String srv[] = att.get(i).toString().split(" ");
+                port = NumberUtils.toInt(srv[2], 5269);
+                host = srv[3];
+            }
+            ctx.close();
+        } catch (NamingException e) {
+            logger.debug("SRV record for {} is not resolved, falling back to A record", hostname);
+        }
+        return new InetSocketAddress(host, port);
+    }
+}