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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License.
18   *
19   */
20  package org.apache.directory.shared.kerberos.codec.actions;
21  
22  
23  import org.apache.directory.api.asn1.DecoderException;
24  import org.apache.directory.api.asn1.ber.Asn1Container;
25  import org.apache.directory.api.asn1.ber.Asn1Decoder;
26  import org.apache.directory.api.asn1.ber.grammar.GrammarAction;
27  import org.apache.directory.api.asn1.ber.tlv.TLV;
28  import org.apache.directory.api.i18n.I18n;
29  import org.apache.directory.shared.kerberos.codec.checksum.ChecksumContainer;
30  import org.apache.directory.shared.kerberos.components.Checksum;
31  import org.slf4j.Logger;
32  import org.slf4j.LoggerFactory;
33  
34  
35  /**
36   * The action used to set the Checksum
37   *
38   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
39   */
40  public abstract class AbstractReadCheckSum<E extends Asn1Container> extends GrammarAction<E>
41  {
42      /** The logger */
43      private static final Logger LOG = LoggerFactory.getLogger( AbstractReadCheckSum.class );
44  
45      /** Speedup for logs */
46      private static final boolean IS_DEBUG = LOG.isDebugEnabled();
47  
48  
49      /**
50       * Instantiates a new AbstractReadChecksum action.
51       */
52      public AbstractReadCheckSum( String name )
53      {
54          super( name );
55      }
56  
57  
58      /**
59       * set the Checksum on the ASN.1 object of the container
60       *
61       * @param checksum the Checksum object
62       * @param container container holding the ASN.1 object
63       */
64      protected abstract void setChecksum( Checksum checksum, E container );
65  
66  
67      /**
68       * {@inheritDoc}
69       */
70      public final void action( E container ) throws DecoderException
71      {
72          TLV tlv = container.getCurrentTLV();
73  
74          // The Length should not be null
75          if ( tlv.getLength() == 0 )
76          {
77              LOG.error( I18n.err( I18n.ERR_01308_ZERO_LENGTH_TLV ) );
78  
79              // This will generate a PROTOCOL_ERROR
80              throw new DecoderException( I18n.err( I18n.ERR_01309_EMPTY_TLV ) );
81          }
82  
83          // Now, let's decode the Checksum
84          ChecksumContainerc/checksum/ChecksumContainer.html#ChecksumContainer">ChecksumContainer checksumContainer = new ChecksumContainer();
85  
86          // Decode the Checksum PDU
87          Asn1Decoder.decode( container.getStream(), checksumContainer );
88  
89          Checksum checksum = checksumContainer.getChecksum();
90  
91          if ( IS_DEBUG )
92          {
93              LOG.debug( "Checksum : {}", checksum );
94          }
95  
96          setChecksum( checksum, container );
97  
98          // Update the expected length for the current TLV
99          tlv.setExpectedLength( tlv.getExpectedLength() - tlv.getLength() );
100 
101         // Update the parent
102         container.updateParent();
103     }
104 }