001    /*
002     * CDDL HEADER START
003     *
004     * The contents of this file are subject to the terms of the
005     * Common Development and Distribution License, Version 1.0 only
006     * (the "License").  You may not use this file except in compliance
007     * with the License.
008     *
009     * You can obtain a copy of the license at
010     * trunk/opends/resource/legal-notices/OpenDS.LICENSE
011     * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
012     * See the License for the specific language governing permissions
013     * and limitations under the License.
014     *
015     * When distributing Covered Code, include this CDDL HEADER in each
016     * file and include the License file at
017     * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
018     * add the following below this CDDL HEADER, with the fields enclosed
019     * by brackets "[]" replaced with your own identifying information:
020     *      Portions Copyright [yyyy] [name of copyright owner]
021     *
022     * CDDL HEADER END
023     *
024     *
025     *      Copyright 2006-2008 Sun Microsystems, Inc.
026     */
027    package org.opends.server.protocols.asn1;
028    import org.opends.messages.Message;
029    
030    
031    
032    import java.io.InputStream;
033    import java.io.IOException;
034    import java.net.Socket;
035    
036    import static org.opends.server.loggers.debug.DebugLogger.*;
037    import org.opends.server.loggers.debug.DebugTracer;
038    import org.opends.server.types.DebugLogLevel;
039    import static org.opends.messages.ProtocolMessages.*;
040    
041    
042    
043    /**
044     * This class defines a utility that can be used to read ASN.1 elements from a
045     * provided socket or input stream.
046     */
047    @org.opends.server.types.PublicAPI(
048         stability=org.opends.server.types.StabilityLevel.UNCOMMITTED,
049         mayInstantiate=true,
050         mayExtend=false,
051         mayInvoke=true)
052    public final class ASN1Reader
053    {
054      /**
055       * The tracer object for the debug logger.
056       */
057      private static final DebugTracer TRACER = getTracer();
058    
059    
060    
061    
062      // The input stream from which to read the ASN.1 elements.
063      private InputStream inputStream;
064    
065      // The largest element size (in bytes) that will be allowed.
066      private int maxElementSize;
067    
068      // The socket with which the input stream is associated.
069      private Socket socket;
070    
071    
072    
073      /**
074       * Creates a new ASN.1 reader that will read elements from the provided
075       * socket.
076       *
077       * @param  socket  The socket from which to read the ASN.1 elements.
078       *
079       * @throws  IOException  If a problem occurs while attempting to obtain the
080       *                       input stream for the socket.
081       */
082      public ASN1Reader(Socket socket)
083             throws IOException
084      {
085        this.socket = socket;
086        inputStream = socket.getInputStream();
087    
088        maxElementSize = -1;
089      }
090    
091    
092    
093      /**
094       * Creates a new ASN.1 reader that will read elements from the provided input
095       * stream.
096       *
097       * @param  inputStream  The input stream from which to read the ASN.1
098       *                      elements.
099       */
100      public ASN1Reader(InputStream inputStream)
101      {
102        this.inputStream = inputStream;
103        socket           = null;
104        maxElementSize   = -1;
105      }
106    
107    
108    
109      /**
110       * Retrieves the maximum size in bytes that will be allowed for elements read
111       * using this reader.  A negative value indicates that no limit should be
112       * enforced.
113       *
114       * @return  The maximum size in bytes that will be allowed for elements.
115       */
116      public int getMaxElementSize()
117      {
118        return maxElementSize;
119      }
120    
121    
122    
123      /**
124       * Specifies the maximum size in bytes that will be allowed for elements.  A
125       * negative value indicates that no limit should be enforced.
126       *
127       * @param  maxElementSize  The maximum size in bytes that will be allowed for
128       *                         elements read using this reader.
129       */
130      public void setMaxElementSize(int maxElementSize)
131      {
132        this.maxElementSize = maxElementSize;
133      }
134    
135    
136    
137      /**
138       * Retrieves the maximum length of time in milliseconds that this reader will
139       * be allowed to block while waiting to read data.  This is only applicable
140       * for readers created with sockets rather than input streams.
141       *
142       * @return  The maximum length of time in milliseconds that this reader will
143       *          be allowed to block while waiting to read data, or 0 if there is
144       *          no limit, or -1 if this ASN.1 reader is not associated with a
145       *          socket and no timeout can be enforced.
146       *
147       * @throws  IOException  If a problem occurs while polling the socket to
148       *                       determine the timeout.
149       */
150      public int getIOTimeout()
151             throws IOException
152      {
153        if (socket == null)
154        {
155          return -1;
156        }
157        else
158        {
159          return socket.getSoTimeout();
160        }
161      }
162    
163    
164    
165      /**
166       * Specifies the maximum length of time in milliseconds that this reader
167       * should be allowed to block while waiting to read data.  This will only be
168       * applicable for readers created with sockets and will have no effect on
169       * readers created with input streams.
170       *
171       * @param  ioTimeout  The maximum length of time in milliseconds that this
172       *                    reader should be allowed to block while waiting to read
173       *                    data, or 0 if there should be no limit.
174       *
175       * @throws  IOException  If a problem occurs while setting the underlying
176       *                       socket option.
177       */
178      public void setIOTimeout(int ioTimeout)
179             throws IOException
180      {
181        if (socket == null)
182        {
183          return;
184        }
185    
186        socket.setSoTimeout(Math.max(0, ioTimeout));
187      }
188    
189    
190    
191      /**
192       * Reads an ASN.1 element from the associated input stream.
193       *
194       * @return  The ASN.1 element read from the associated input stream, or
195       *          <CODE>null</CODE> if the end of the stream has been reached.
196       *
197       * @throws  IOException  If a problem occurs while attempting to read from the
198       *                       input stream.
199       *
200       * @throws  ASN1Exception  If a problem occurs while attempting to decode the
201       *                         data read as an ASN.1 element.
202       */
203      public ASN1Element readElement()
204             throws IOException, ASN1Exception
205      {
206        // First, read the BER type, which should be the first byte.
207        int typeValue = inputStream.read();
208        if (typeValue < 0)
209        {
210          return null;
211        }
212    
213        byte type = (byte) (typeValue & 0xFF);
214    
215    
216    
217        // Next, read the first byte of the length, and see if we need to read more.
218        int length         = inputStream.read();
219        int numLengthBytes = (length & 0x7F);
220        if (length != numLengthBytes)
221        {
222          // Make sure that there are an acceptable number of bytes in the length.
223          if (numLengthBytes > 4)
224          {
225            Message message =
226                ERR_ASN1_ELEMENT_SET_INVALID_NUM_LENGTH_BYTES.get(numLengthBytes);
227            throw new ASN1Exception(message);
228          }
229    
230    
231          length = 0;
232          for (int i=0; i < numLengthBytes; i++)
233          {
234            int lengthByte = inputStream.read();
235            if (lengthByte < 0)
236            {
237              // We've reached the end of the stream in the middle of the value.
238              // This is not good, so throw an exception.
239              Message message =
240                  ERR_ASN1_ELEMENT_SET_TRUNCATED_LENGTH.get(numLengthBytes);
241              throw new IOException(message.toString());
242            }
243    
244            length = (length << 8) | lengthByte;
245          }
246        }
247    
248    
249        // See how many bytes there are in the value.  If there are none, then just
250        // create an empty element with only a type.  If the length is larger than
251        // the maximum allowed, then fail.
252        if (length == 0)
253        {
254          return new ASN1Element(type);
255        }
256        else if ((maxElementSize > 0) && (length > maxElementSize))
257        {
258          Message message =
259              ERR_ASN1_READER_MAX_SIZE_EXCEEDED.get(length, maxElementSize);
260          throw new ASN1Exception(message);
261        }
262    
263    
264        // There is a value for the element, so create an array to hold it and read
265        // it from the stream.
266        byte[] value       = new byte[length];
267        int    readPos     = 0;
268        int    bytesNeeded = length;
269        while (bytesNeeded > 0)
270        {
271          int bytesRead = inputStream.read(value, readPos, bytesNeeded);
272          if (bytesRead < 0)
273          {
274            Message message =
275                ERR_ASN1_ELEMENT_SET_TRUNCATED_VALUE.get(length, bytesNeeded);
276            throw new IOException(message.toString());
277          }
278    
279          bytesNeeded -= bytesRead;
280          readPos     += bytesRead;
281        }
282    
283    
284        // Return the constructed element.
285        return new ASN1Element(type, value);
286      }
287    
288    
289    
290      /**
291       * Closes this ASN.1 reader and the underlying input stream and/or socket.
292       */
293      public void close()
294      {
295        try
296        {
297          inputStream.close();
298        }
299        catch (Exception e)
300        {
301          if (debugEnabled())
302          {
303            TRACER.debugCaught(DebugLogLevel.ERROR, e);
304          }
305        }
306    
307        if (socket != null)
308        {
309          try
310          {
311            socket.close();
312          }
313          catch (Exception e)
314          {
315            if (debugEnabled())
316            {
317              TRACER.debugCaught(DebugLogLevel.ERROR, e);
318            }
319          }
320        }
321      }
322    }
323