001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.directory.shared.kerberos.codec.actions; 021 022 023import org.apache.directory.api.asn1.DecoderException; 024import org.apache.directory.api.asn1.ber.Asn1Container; 025import org.apache.directory.api.asn1.ber.Asn1Decoder; 026import org.apache.directory.api.asn1.ber.grammar.GrammarAction; 027import org.apache.directory.api.asn1.ber.tlv.TLV; 028import org.apache.directory.api.i18n.I18n; 029import org.apache.directory.shared.kerberos.codec.checksum.ChecksumContainer; 030import org.apache.directory.shared.kerberos.components.Checksum; 031import org.slf4j.Logger; 032import org.slf4j.LoggerFactory; 033 034 035/** 036 * The action used to set the Checksum 037 * 038 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 039 */ 040public abstract class AbstractReadCheckSum<E extends Asn1Container> extends GrammarAction<E> 041{ 042 /** The logger */ 043 private static final Logger LOG = LoggerFactory.getLogger( AbstractReadCheckSum.class ); 044 045 /** Speedup for logs */ 046 private static final boolean IS_DEBUG = LOG.isDebugEnabled(); 047 048 049 /** 050 * Instantiates a new AbstractReadChecksum action. 051 */ 052 public AbstractReadCheckSum( String name ) 053 { 054 super( name ); 055 } 056 057 058 /** 059 * set the Checksum on the ASN.1 object of the container 060 * 061 * @param checksum the Checksum object 062 * @param container container holding the ASN.1 object 063 */ 064 protected abstract void setChecksum( Checksum checksum, E container ); 065 066 067 /** 068 * {@inheritDoc} 069 */ 070 public final void action( E container ) throws DecoderException 071 { 072 TLV tlv = container.getCurrentTLV(); 073 074 // The Length should not be null 075 if ( tlv.getLength() == 0 ) 076 { 077 LOG.error( I18n.err( I18n.ERR_01308_ZERO_LENGTH_TLV ) ); 078 079 // This will generate a PROTOCOL_ERROR 080 throw new DecoderException( I18n.err( I18n.ERR_01309_EMPTY_TLV ) ); 081 } 082 083 // Now, let's decode the Checksum 084 ChecksumContainer checksumContainer = new ChecksumContainer(); 085 086 // Decode the Checksum PDU 087 Asn1Decoder.decode( container.getStream(), checksumContainer ); 088 089 Checksum checksum = checksumContainer.getChecksum(); 090 091 if ( IS_DEBUG ) 092 { 093 LOG.debug( "Checksum : {}", checksum ); 094 } 095 096 setChecksum( checksum, container ); 097 098 // Update the expected length for the current TLV 099 tlv.setExpectedLength( tlv.getExpectedLength() - tlv.getLength() ); 100 101 // Update the parent 102 container.updateParent(); 103 } 104}