chris@1: /*
chris@1:  *   SONEWS News Server
chris@1:  *   see AUTHORS for the list of contributors
chris@1:  *
chris@1:  *   This program is free software: you can redistribute it and/or modify
chris@1:  *   it under the terms of the GNU General Public License as published by
chris@1:  *   the Free Software Foundation, either version 3 of the License, or
chris@1:  *   (at your option) any later version.
chris@1:  *
chris@1:  *   This program is distributed in the hope that it will be useful,
chris@1:  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
chris@1:  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
chris@1:  *   GNU General Public License for more details.
chris@1:  *
chris@1:  *   You should have received a copy of the GNU General Public License
chris@1:  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
chris@1:  */
chris@1: 
chris@1: package org.sonews.daemon;
chris@1: 
chris@1: import org.sonews.util.Log;
chris@1: import java.io.IOException;
chris@1: import java.net.InetSocketAddress;
chris@1: import java.nio.ByteBuffer;
chris@1: import java.nio.CharBuffer;
chris@1: import java.nio.channels.ClosedChannelException;
chris@1: import java.nio.channels.SelectionKey;
chris@1: import java.nio.channels.SocketChannel;
chris@1: import java.nio.charset.Charset;
chris@1: import java.util.Timer;
chris@1: import java.util.TimerTask;
chris@1: import org.sonews.daemon.command.ArticleCommand;
chris@1: import org.sonews.daemon.command.CapabilitiesCommand;
chris@1: import org.sonews.daemon.command.AbstractCommand;
chris@1: import org.sonews.daemon.command.GroupCommand;
chris@1: import org.sonews.daemon.command.HelpCommand;
chris@1: import org.sonews.daemon.command.ListCommand;
chris@1: import org.sonews.daemon.command.ListGroupCommand;
chris@1: import org.sonews.daemon.command.ModeReaderCommand;
chris@1: import org.sonews.daemon.command.NewGroupsCommand;
chris@1: import org.sonews.daemon.command.NextPrevCommand;
chris@1: import org.sonews.daemon.command.OverCommand;
chris@1: import org.sonews.daemon.command.PostCommand;
chris@1: import org.sonews.daemon.command.QuitCommand;
chris@1: import org.sonews.daemon.command.StatCommand;
chris@1: import org.sonews.daemon.command.UnsupportedCommand;
chris@1: import org.sonews.daemon.command.XDaemonCommand;
chris@1: import org.sonews.daemon.command.XPatCommand;
chris@1: import org.sonews.daemon.storage.Article;
chris@1: import org.sonews.daemon.storage.Group;
chris@1: import org.sonews.util.Stats;
chris@1: 
chris@1: /**
chris@1:  * For every SocketChannel (so TCP/IP connection) there is an instance of
chris@1:  * this class.
chris@1:  * @author Christian Lins
chris@1:  * @since sonews/0.5.0
chris@1:  */
chris@1: public final class NNTPConnection
chris@1: {
chris@1: 
chris@1:   public static final String NEWLINE            = "\r\n";    // RFC defines this as newline
chris@1:   public static final String MESSAGE_ID_PATTERN = "<[^>]+>";
chris@1:   
chris@1:   private static final Timer cancelTimer = new Timer(true); // Thread-safe? True for run as daemon
chris@1:   
chris@1:   /** SocketChannel is generally thread-safe */
chris@1:   private SocketChannel   channel        = null;
chris@1:   private Charset         charset        = Charset.forName("UTF-8");
chris@1:   private AbstractCommand command        = null;
chris@1:   private Article         currentArticle = null;
chris@1:   private Group           currentGroup   = null;
chris@1:   private volatile long   lastActivity   = System.currentTimeMillis();
chris@1:   private ChannelLineBuffers lineBuffers = new ChannelLineBuffers();
chris@1:   private int             readLock       = 0;
chris@1:   private final Object    readLockGate   = new Object();
chris@1:   private SelectionKey    writeSelKey    = null;
chris@1:   
chris@1:   public NNTPConnection(final SocketChannel channel)
chris@1:     throws IOException
chris@1:   {
chris@1:     if(channel == null)
chris@1:     {
chris@1:       throw new IllegalArgumentException("channel is null");
chris@1:     }
chris@1: 
chris@1:     this.channel = channel;
chris@1:     Stats.getInstance().clientConnect();
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * Tries to get the read lock for this NNTPConnection. This method is Thread-
chris@1:    * safe and returns true of the read lock was successfully set. If the lock
chris@1:    * is still hold by another Thread the method returns false.
chris@1:    */
chris@1:   boolean tryReadLock()
chris@1:   {
chris@1:     // As synchronizing simple types may cause deadlocks,
chris@1:     // we use a gate object.
chris@1:     synchronized(readLockGate)
chris@1:     {
chris@1:       if(readLock != 0)
chris@1:       {
chris@1:         return false;
chris@1:       }
chris@1:       else
chris@1:       {
chris@1:         readLock = Thread.currentThread().hashCode();
chris@1:         return true;
chris@1:       }
chris@1:     }
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * Releases the read lock in a Thread-safe way.
chris@1:    * @throws IllegalMonitorStateException if a Thread not holding the lock
chris@1:    * tries to release it.
chris@1:    */
chris@1:   void unlockReadLock()
chris@1:   {
chris@1:     synchronized(readLockGate)
chris@1:     {
chris@1:       if(readLock == Thread.currentThread().hashCode())
chris@1:       {
chris@1:         readLock = 0;
chris@1:       }
chris@1:       else
chris@1:       {
chris@1:         throw new IllegalMonitorStateException();
chris@1:       }
chris@1:     }
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * @return Current input buffer of this NNTPConnection instance.
chris@1:    */
chris@1:   public ByteBuffer getInputBuffer()
chris@1:   {
chris@1:     return this.lineBuffers.getInputBuffer();
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * @return Output buffer of this NNTPConnection which has at least one byte
chris@1:    * free storage.
chris@1:    */
chris@1:   public ByteBuffer getOutputBuffer()
chris@1:   {
chris@1:     return this.lineBuffers.getOutputBuffer();
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * @return ChannelLineBuffers instance associated with this NNTPConnection.
chris@1:    */
chris@1:   public ChannelLineBuffers getBuffers()
chris@1:   {
chris@1:     return this.lineBuffers;
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * @return true if this connection comes from a local remote address.
chris@1:    */
chris@1:   public boolean isLocalConnection()
chris@1:   {
chris@1:     return ((InetSocketAddress)this.channel.socket().getRemoteSocketAddress())
chris@1:       .getHostName().equalsIgnoreCase("localhost");
chris@1:   }
chris@1: 
chris@1:   void setWriteSelectionKey(SelectionKey selKey)
chris@1:   {
chris@1:     this.writeSelKey = selKey;
chris@1:   }
chris@1: 
chris@1:   public void shutdownInput()
chris@1:   {
chris@1:     try
chris@1:     {
chris@1:       // Closes the input line of the channel's socket, so no new data
chris@1:       // will be received and a timeout can be triggered.
chris@1:       this.channel.socket().shutdownInput();
chris@1:     }
chris@1:     catch(IOException ex)
chris@1:     {
chris@1:       Log.msg("Exception in NNTPConnection.shutdownInput(): " + ex, false);
chris@1:       if(Log.isDebug())
chris@1:       {
chris@1:         ex.printStackTrace();
chris@1:       }
chris@1:     }
chris@1:   }
chris@1:   
chris@1:   public void shutdownOutput()
chris@1:   {
chris@1:     cancelTimer.schedule(new TimerTask() 
chris@1:     {
chris@1:       @Override
chris@1:       public void run()
chris@1:       {
chris@1:         try
chris@1:         {
chris@1:           // Closes the output line of the channel's socket.
chris@1:           channel.socket().shutdownOutput();
chris@1:           channel.close();
chris@1:         }
chris@1:         catch(Exception ex)
chris@1:         {
chris@1:           Log.msg("NNTPConnection.shutdownOutput(): " + ex, false);
chris@1:           if(Log.isDebug())
chris@1:           {
chris@1:             ex.printStackTrace();
chris@1:           }
chris@1:         }
chris@1:       }
chris@1:     }, 3000);
chris@1:   }
chris@1:   
chris@1:   public SocketChannel getChannel()
chris@1:   {
chris@1:     return this.channel;
chris@1:   }
chris@1:   
chris@1:   public Article getCurrentArticle()
chris@1:   {
chris@1:     return this.currentArticle;
chris@1:   }
chris@1:   
chris@1:   public Charset getCurrentCharset()
chris@1:   {
chris@1:     return this.charset;
chris@1:   }
chris@1:   
chris@1:   public Group getCurrentGroup()
chris@1:   {
chris@1:     return this.currentGroup;
chris@1:   }
chris@1:   
chris@1:   public void setCurrentArticle(final Article article)
chris@1:   {
chris@1:     this.currentArticle = article;
chris@1:   }
chris@1:   
chris@1:   public void setCurrentGroup(final Group group)
chris@1:   {
chris@1:     this.currentGroup = group;
chris@1:   }
chris@1:   
chris@1:   public long getLastActivity()
chris@1:   {
chris@1:     return this.lastActivity;
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * Due to the readLockGate there is no need to synchronize this method.
chris@1:    * @param raw
chris@1:    * @throws IllegalArgumentException if raw is null.
chris@1:    * @throws IllegalStateException if calling thread does not own the readLock.
chris@1:    */
chris@1:   void lineReceived(byte[] raw)
chris@1:   {
chris@1:     if(raw == null)
chris@1:     {
chris@1:       throw new IllegalArgumentException("raw is null");
chris@1:     }
chris@1:     
chris@1:     if(readLock == 0 || readLock != Thread.currentThread().hashCode())
chris@1:     {
chris@1:       throw new IllegalStateException("readLock not properly set");
chris@1:     }
chris@1: 
chris@1:     this.lastActivity = System.currentTimeMillis();
chris@1:     
chris@1:     String line = new String(raw, this.charset);
chris@1:     
chris@1:     // There might be a trailing \r, but trim() is a bad idea
chris@1:     // as it removes also leading spaces from long header lines.
chris@1:     if(line.endsWith("\r"))
chris@1:     {
chris@1:       line = line.substring(0, line.length() - 1);
chris@1:     }
chris@1:     
chris@1:     Log.msg("<< " + line, true);
chris@1:     
chris@1:     if(command == null)
chris@1:     {
chris@1:       command = parseCommandLine(line);
chris@1:       assert command != null;
chris@1:     }
chris@1: 
chris@1:     try
chris@1:     {
chris@1:       // The command object will process the line we just received
chris@1:       command.processLine(line);
chris@1:     }
chris@1:     catch(ClosedChannelException ex0)
chris@1:     {
chris@1:       try
chris@1:       {
chris@1:         Log.msg("Connection to " + channel.socket().getRemoteSocketAddress() 
chris@1:             + " closed: " + ex0, true);
chris@1:       }
chris@1:       catch(Exception ex0a)
chris@1:       {
chris@1:         ex0a.printStackTrace();
chris@1:       }
chris@1:     }
chris@1:     catch(Exception ex1)
chris@1:     {
chris@1:       try
chris@1:       {
chris@1:         command = null;
chris@1:         ex1.printStackTrace();
chris@1:         println("500 Internal server error");
chris@1:       }
chris@1:       catch(Exception ex2)
chris@1:       {
chris@1:         ex2.printStackTrace();
chris@1:       }
chris@1:     }
chris@1: 
chris@1:     if(command == null || command.hasFinished())
chris@1:     {
chris@1:       command = null;
chris@1:       charset = Charset.forName("UTF-8"); // Reset to default
chris@1:     }
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * This method performes several if/elseif constructs to determine the
chris@1:    * fitting command object. 
chris@1:    * TODO: This string comparisons are probably slow!
chris@1:    * @param line
chris@1:    * @return
chris@1:    */
chris@1:   private AbstractCommand parseCommandLine(String line)
chris@1:   {
chris@1:     AbstractCommand  cmd    = new UnsupportedCommand(this);
chris@1:     String   cmdStr = line.split(" ")[0];
chris@1:     
chris@1:     if(cmdStr.equalsIgnoreCase("ARTICLE") || 
chris@1:       cmdStr.equalsIgnoreCase("BODY"))
chris@1:     {
chris@1:       cmd = new ArticleCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("CAPABILITIES"))
chris@1:     {
chris@1:       cmd = new CapabilitiesCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("GROUP"))
chris@1:     {
chris@1:       cmd = new GroupCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("HEAD"))
chris@1:     {
chris@1:       cmd = new ArticleCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("HELP"))
chris@1:     {
chris@1:       cmd = new HelpCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("LIST"))
chris@1:     {
chris@1:       cmd = new ListCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("LISTGROUP"))
chris@1:     {
chris@1:       cmd = new ListGroupCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("MODE"))
chris@1:     {
chris@1:       cmd = new ModeReaderCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("NEWGROUPS"))
chris@1:     {
chris@1:       cmd = new NewGroupsCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("NEXT") ||
chris@1:       cmdStr.equalsIgnoreCase("PREV"))
chris@1:     {
chris@1:       cmd = new NextPrevCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("OVER") ||
chris@1:       cmdStr.equalsIgnoreCase("XOVER")) // for compatibility with older RFCs
chris@1:     {
chris@1:       cmd = new OverCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("POST"))
chris@1:     {
chris@1:       cmd = new PostCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("QUIT"))
chris@1:     {
chris@1:       cmd = new QuitCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("STAT"))
chris@1:     {
chris@1:       cmd = new StatCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("XDAEMON"))
chris@1:     {
chris@1:       cmd = new XDaemonCommand(this);
chris@1:     }
chris@1:     else if(cmdStr.equalsIgnoreCase("XPAT"))
chris@1:     {
chris@1:       cmd = new XPatCommand(this);
chris@1:     }
chris@1:     
chris@1:     return cmd;
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * Puts the given line into the output buffer, adds a newline character
chris@1:    * and returns. The method returns immediately and does not block until
chris@1:    * the line was sent. If line is longer than 510 octets it is split up in
chris@1:    * several lines. Each line is terminated by \r\n (NNTPConnection.NEWLINE).
chris@1:    * @param line
chris@1:    */
chris@1:   public void println(final CharSequence line, final Charset charset)
chris@1:     throws IOException
chris@1:   {    
chris@1:     writeToChannel(CharBuffer.wrap(line), charset, line);
chris@1:     writeToChannel(CharBuffer.wrap(NEWLINE), charset, null);
chris@1:   }
chris@1:   
chris@1:   /**
chris@1:    * Encodes the given CharBuffer using the given Charset to a bunch of
chris@1:    * ByteBuffers (each 512 bytes large) and enqueues them for writing at the
chris@1:    * connected SocketChannel.
chris@1:    * @throws java.io.IOException
chris@1:    */
chris@1:   private void writeToChannel(CharBuffer characters, final Charset charset,
chris@1:     CharSequence debugLine)
chris@1:     throws IOException
chris@1:   {
chris@1:     if(!charset.canEncode())
chris@1:     {
chris@1:       Log.msg("FATAL: Charset " + charset + " cannot encode!", false);
chris@1:       return;
chris@1:     }
chris@1:     
chris@1:     // Write characters to output buffers
chris@1:     LineEncoder lenc = new LineEncoder(characters, charset);
chris@1:     lenc.encode(lineBuffers);
chris@1:     
chris@1:     // Enable OP_WRITE events so that the buffers are processed
chris@1:     try
chris@1:     {
chris@1:       this.writeSelKey.interestOps(SelectionKey.OP_WRITE);
chris@1:       ChannelWriter.getInstance().getSelector().wakeup();
chris@1:     }
chris@1:     catch (Exception ex) // CancelledKeyException and ChannelCloseException
chris@1:     {
chris@1:       Log.msg("NNTPConnection.writeToChannel(): " + ex, false);
chris@1:       return;
chris@1:     }
chris@1: 
chris@1:     // Update last activity timestamp
chris@1:     this.lastActivity = System.currentTimeMillis();
chris@1:     if(debugLine != null)
chris@1:     {
chris@1:       Log.msg(">> " + debugLine, true);
chris@1:     }
chris@1:   }
chris@1:   
chris@1:   public void println(final CharSequence line)
chris@1:     throws IOException
chris@1:   {
chris@1:     println(line, charset);
chris@1:   }
chris@1:   
chris@1:   public void print(final String line)
chris@1:     throws IOException
chris@1:   {
chris@1:     writeToChannel(CharBuffer.wrap(line), charset, line);
chris@1:   }
chris@1:   
chris@1:   public void setCurrentCharset(final Charset charset)
chris@1:   {
chris@1:     this.charset = charset;
chris@1:   }
chris@1:   
chris@1: }