/*
    *  Licensed to the Apache Software Foundation (ASF) under one
    *  or more contributor license agreements.  See the NOTICE file
    *  distributed with this work for additional information
    *  regarding copyright ownership.  The ASF licenses this file
    *  to you under the Apache License, Version 2.0 (the
    *  "License"); you may not use this file except in compliance
    *  with the License.  You may obtain a copy of the License at
    *  
   *    http://www.apache.org/licenses/LICENSE-2.0
   *  
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License. 
   *  
   */
  package org.apache.directory.server.dns;
  
  
  import java.io.IOException;
  
  import org.apache.directory.server.dns.protocol.DnsProtocolHandler;
  import org.apache.directory.server.dns.store.RecordStore;
  import org.apache.directory.server.dns.store.jndi.JndiRecordStoreImpl;
  import org.apache.directory.server.protocol.shared.DirectoryBackedService;
  import org.apache.directory.server.protocol.shared.transport.Transport;
  import org.apache.directory.server.protocol.shared.transport.UdpTransport;
  import org.apache.mina.core.service.IoAcceptor;
  import org.apache.mina.transport.socket.DatagramAcceptor;
  import org.apache.mina.transport.socket.DatagramSessionConfig;
  import org.apache.mina.transport.socket.nio.NioSocketAcceptor;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Contains the configuration parameters for the DNS protocol provider.
   *
   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
   */
  public class DnsServer extends DirectoryBackedService
  {
      private static final long serialVersionUID = 6943138644427163149L;
  
      /** logger for this class */
      private static final Logger LOG = LoggerFactory.getLogger( DnsServer.class );
  
      /** The default IP port. */
      private static final int DEFAULT_IP_PORT = 53;
  
      /** The default service pid. */
      private static final String SERVICE_PID_DEFAULT = "org.apache.directory.server.dns";
  
      /** The default service name. */
      private static final String SERVICE_NAME_DEFAULT = "ApacheDS DNS Service";
  
  
      /**
       * Creates a new instance of DnsConfiguration.
       */
      public DnsServer()
      {
          super.setServiceId( SERVICE_PID_DEFAULT );
          super.setServiceName( SERVICE_NAME_DEFAULT );
      }
  
  
      /**
       * @throws IOException if we cannot bind to the specified ports
       */
      public void start() throws IOException
      {
          RecordStore store = new JndiRecordStoreImpl( getSearchBaseDn(), getSearchBaseDn(), getDirectoryService() );
  
          if ( ( transports == null ) || transports.isEmpty() )
          {
              // Default to UDP with port 53
              // We have to create a DatagramAcceptor
              UdpTransportol/shared/transport/UdpTransport.html#UdpTransport">UdpTransport transport = new UdpTransport( DEFAULT_IP_PORT );
              setTransports( transport );
  
              DatagramAcceptor acceptor = transport.getAcceptor();
  
              // Set the handler
              acceptor.setHandler( new DnsProtocolHandler( this, store ) );
  
              // Allow the port to be reused even if the socket is in TIME_WAIT state
               acceptor.getSessionConfig().setReuseAddress( true );
  
              // Start the listener
              acceptor.bind();
          }
          else
          {
              for ( Transport transport : transports )
              {
                 // Get the acceptor
                 IoAcceptor acceptor = transport.getAcceptor();
 
                 // Set the handler
                 acceptor.setHandler( new DnsProtocolHandler( this, store ) );
 
                 if ( transport instanceof UdpTransport )
                 {
                     // Allow the port to be reused even if the socket is in TIME_WAIT state
                     ( ( DatagramSessionConfig ) acceptor.getSessionConfig() ).setReuseAddress( true );
                 }
                 else
                 {
                     // Disable the disconnection of the clients on unbind
                     acceptor.setCloseOnDeactivation( false );
 
                     // Allow the port to be reused even if the socket is in TIME_WAIT state
                     ( ( NioSocketAcceptor ) acceptor ).setReuseAddress( true );
 
                     // No Nagle's algorithm
                     ( ( NioSocketAcceptor ) acceptor ).getSessionConfig().setTcpNoDelay( true );
                 }
 
                 // Start the listener
                 acceptor.bind();
             }
         }
 
         LOG.info( "DNS service started." );
     }
 
 
     public void stop()
     {
         for ( Transport transport : getTransports() )
         {
             IoAcceptor acceptor = transport.getAcceptor();
 
             if ( acceptor != null )
             {
                 acceptor.dispose();
             }
         }
 
         LOG.info( "DNS service stopped." );
     }
 
 
     /**
      * @see Object#toString()
      */
     public String toString()
     {
         StringBuilder sb = new StringBuilder();
 
         sb.append( "DNSServer[" ).append( getServiceName() ).append( "], listening on :" ).append( '\n' );
 
         if ( getTransports() != null )
         {
             for ( Transport transport : getTransports() )
             {
                 sb.append( "    " ).append( transport ).append( '\n' );
             }
         }
 
         return sb.toString();
     }
 }