355 lines
10 KiB
C++
355 lines
10 KiB
C++
#include "precomp.h"
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DEBUG_FILEZONE(ZONE_T120_GCCNC);
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/*
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* ogcccode.cpp
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*
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* Copyright (c) 1994 by DataBeam Corporation, Lexington, KY
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*
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* Abstract:
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* This is the implementation file for the CGCCCoder class. This class
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* is responsible for encoding and decoding GCC (T.124) PDU's using ASN.1
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* encoding rules via the ASN.1 toolkit. This class is also capable
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* of determining the size of both the encoded and decoded PDU's.
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*
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* Static Variables:
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*
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* Caveats:
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* Only one instance of this class should be in existance at any one time
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* due to the static variable.
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*
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* Author:
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* John B. O'Nan
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*/
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/*
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* External Interfaces
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*/
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#include <string.h>
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#include "ogcccode.h"
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/*
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* This is a global variable that has a pointer to the one GCC coder that
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* is instantiated by the GCC Controller. Most objects know in advance
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* whether they need to use the MCS or the GCC coder, so, they do not need
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* this pointer in their constructors.
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*/
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CGCCCoder *g_GCCCoder;
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/*
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* CGCCCoder ()
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*
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* Public
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*
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* Functional Description:
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* This is the constructor for the CGCCCoder class. It initializes
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* the ASN.1 encoder/decoder and sets the encoding rules to the
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* Packed-Aligned variant.
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*/
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CGCCCoder::CGCCCoder ()
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:m_pEncInfo(NULL),
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m_pDecInfo(NULL)
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{
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// lonchanc: We should move Init out of constructor. However,
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// to minimize the changes in the GCC/MCS code, we put it here for now.
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// Otherwise, we need to change MCS and Packet interfaces.
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// We will move it out and call Init() separately.
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Init();
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}
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BOOL CGCCCoder::Init ( void )
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{
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BOOL fRet = FALSE;
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GCCPDU_Module_Startup();
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if (GCCPDU_Module != NULL)
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{
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if (ASN1_CreateEncoder(
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GCCPDU_Module, // ptr to mdule
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&m_pEncInfo, // ptr to encoder info
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NULL, // buffer ptr
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0, // buffer size
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NULL) // parent ptr
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== ASN1_SUCCESS)
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{
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ASSERT(m_pEncInfo != NULL);
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fRet = (ASN1_CreateDecoder(
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GCCPDU_Module, // ptr to mdule
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&m_pDecInfo, // ptr to decoder info
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NULL, // buffer ptr
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0, // buffer size
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NULL) // parent ptr
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== ASN1_SUCCESS);
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ASSERT(fRet && m_pDecInfo != NULL);
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}
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}
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ASSERT(fRet);
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return fRet;
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}
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/*
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* ~CGCCCoder ()
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*
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* Public Functional Description:
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* This is a virtual destructor. It is used to clean up after ASN.1.
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*/
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CGCCCoder::~CGCCCoder ()
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{
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if (GCCPDU_Module != NULL)
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{
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ASN1_CloseEncoder(m_pEncInfo);
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ASN1_CloseDecoder(m_pDecInfo);
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GCCPDU_Module_Cleanup();
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}
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}
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/*
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* Encode ()
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*
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* Public Functional Description:
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* This function encodes GCC Protocol Data Units (PDU's) into ASN.1
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* compliant byte streams using the ASN.1 toolkit.
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* The coder allocates the buffer space for the encoded data.
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*/
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BOOL CGCCCoder::Encode(LPVOID pdu_structure,
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int pdu_type,
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UINT nEncodingRule_not_used,
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LPBYTE *encoding_buffer,
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UINT *encoding_buffer_length)
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{
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BOOL fRet = FALSE;
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int return_value;
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ConnectData connect_data_structure;
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// clean up local buffer pointer
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connect_data_structure.connect_pdu.value = NULL;
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/*
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* If the PDU to be encoded is a "ConnectGCC" PDU we must first encode the
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* "ConnectGCC" PDU. A "ConnectData" PDU structure is then built which
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* contains the encoded "ConnectGCC" PDU along with object identifier key.
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* The "ConnectData" PDU is then encoded into the provided buffer.
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*/
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if (pdu_type == CONNECT_GCC_PDU)
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{
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return_value = ASN1_Encode(m_pEncInfo, // ptr to encoder info
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pdu_structure, // pdu data structure
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pdu_type, // pdu id
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ASN1ENCODE_ALLOCATEBUFFER, // flags
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NULL, // do not provide buffer
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0); // buffer size if provided
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if (ASN1_FAILED(return_value))
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{
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ERROR_OUT(("CGCCCoder::Encode: ASN1_Encode failed, err=%d in CONNECT_GCC_PDU.",
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return_value));
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ASSERT(FALSE);
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goto MyExit;
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}
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ASSERT(return_value == ASN1_SUCCESS);
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/*
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* Fill in the "ConnectData" PDU structure and encode it.
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*/
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connect_data_structure.t124_identifier = t124identifier;
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connect_data_structure.connect_pdu.length = m_pEncInfo->len; // len of encoded data in buffer
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connect_data_structure.connect_pdu.value = m_pEncInfo->buf; // buffer to encode into
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// Prepare for the encode call
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pdu_structure = (LPVOID) &connect_data_structure;
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pdu_type = CONNECT_DATA_PDU;
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}
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/*
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* Encode the Non-Connect PDU into the buffer provided.
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*/
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return_value = ASN1_Encode(m_pEncInfo, // ptr to encoder info
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pdu_structure, // pdu data structure
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pdu_type, // pdu id
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ASN1ENCODE_ALLOCATEBUFFER, // flags
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NULL, // do not provide buffer
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0); // buffer size if provided
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if (ASN1_FAILED(return_value))
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{
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ERROR_OUT(("CGCCCoder::Encode: ASN1_Encode failed, err=%d", return_value));
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ASSERT(FALSE);
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goto MyExit;
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}
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ASSERT(return_value == ASN1_SUCCESS);
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*encoding_buffer_length = m_pEncInfo->len; // len of encoded data in buffer
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*encoding_buffer = m_pEncInfo->buf; // buffer to encode into
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fRet = TRUE;
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MyExit:
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/*
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* If this was a CONNECT_DATA_PDU we need to free the buffer that
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* was allocated by ASN.1.
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*/
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if (CONNECT_DATA_PDU == pdu_type && connect_data_structure.connect_pdu.value != NULL)
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{
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ASN1_FreeEncoded(m_pEncInfo, connect_data_structure.connect_pdu.value);
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}
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return fRet;
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}
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/*
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* Decode ()
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*
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* Public Functional Description:
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* This function decodes ASN.1 compliant byte streams into the
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* appropriate GCC PDU structures using the ASN.1 toolkit.
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*/
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BOOL CGCCCoder::Decode(LPBYTE encoded_buffer,
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UINT encoded_buffer_length,
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int pdu_type,
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UINT nEncodingRule_not_used,
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LPVOID *pdecoding_buffer,
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UINT *pdecoding_buffer_length)
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{
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BOOL fRet = FALSE;
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int return_value;
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LPVOID connect_data_decoding_buffer = NULL;
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ASN1optionparam_s OptParam;
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/*
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* If the PDU is a "ConnectGCC" PDU then after it is decoded we must decode
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* the "ConnectGCC" PDU which is actually contained within a "ConnectData"
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* PDU.
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*/
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if (pdu_type == CONNECT_GCC_PDU)
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{
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return_value = ASN1_Decode(m_pDecInfo, // ptr to decoder info
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&connect_data_decoding_buffer, // destination buffer
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CONNECT_DATA_PDU, // pdu type
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ASN1DECODE_SETBUFFER, // flags
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encoded_buffer, // source buffer
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encoded_buffer_length); // source buffer size
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if (ASN1_FAILED(return_value))
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{
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ERROR_OUT(("CGCCCoder::Decode: ASN1_Decode failed, err=%d", return_value));
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ASSERT(FALSE);
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goto MyExit;
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}
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ASSERT(return_value == ASN1_SUCCESS);
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/*
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* If the decoded PDU is a "ConnectData" PDU, then we first must check
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* to make sure this PDU originated from a T.124-compliant source.
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* If so we then decode the "ConnectGCC" PDU which is held in the
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* "connect_pdu" field. If the PDU is not T.124-compliant, we will
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* report an error which will cause the PDU to be rejected.
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*/
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if (IsObjectIDCompliant(&(((PConnectData) connect_data_decoding_buffer)->t124_identifier))
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== FALSE)
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{
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ERROR_OUT(("CGCCCoder::Decode: Non-T.124 objectID"));
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ASSERT (FALSE);
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goto MyExit;
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}
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ASSERT(connect_data_decoding_buffer != NULL);
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encoded_buffer = (PUChar)((PConnectData) connect_data_decoding_buffer)->
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connect_pdu.value;
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encoded_buffer_length = (UINT)((PConnectData) connect_data_decoding_buffer)->
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connect_pdu.length;
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}
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/*
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* Decode the Non-Connect PDU into the buffer provided.
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*/
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return_value = ASN1_Decode(m_pDecInfo, // ptr to decoder info
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pdecoding_buffer, // destination buffer
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pdu_type, // pdu type
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ASN1DECODE_SETBUFFER, // flags
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encoded_buffer, // source buffer
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encoded_buffer_length); // source buffer size
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if (ASN1_FAILED(return_value))
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{
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ERROR_OUT(("CCCCoder::Decode: ASN1_Decode failed, err=%d", return_value));
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ASSERT(FALSE);
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goto MyExit;
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}
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ASSERT(return_value == ASN1_SUCCESS);
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OptParam.eOption = ASN1OPT_GET_DECODED_BUFFER_SIZE;
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return_value = ASN1_GetDecoderOption(m_pDecInfo, &OptParam);
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if (ASN1_FAILED(return_value))
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{
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ERROR_OUT(("CGCCCoder::Decode: ASN1_GetDecoderOption failed, err=%d", return_value));
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ASSERT(FALSE);
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goto MyExit;
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}
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*pdecoding_buffer_length = OptParam.cbRequiredDecodedBufSize;
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ASSERT(return_value == ASN1_SUCCESS);
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ASSERT(*pdecoding_buffer_length > 0);
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fRet = TRUE;
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MyExit:
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/*
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* Free the PDU structure allocated by decoder for the Connect-Data PDU.
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*/
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if (connect_data_decoding_buffer != NULL)
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{
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ASSERT (pdu_type == CONNECT_GCC_PDU);
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ASN1_FreeDecoded(m_pDecInfo, connect_data_decoding_buffer, CONNECT_DATA_PDU);
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}
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return fRet;
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}
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/*
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* IsObjectIDCompliant ()
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*
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* Private Functional Description:
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* This function is used to verify that the object identifier contained
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* in a "Connect" PDU is compliant with this version of GCC.
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*/
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BOOL CGCCCoder::IsObjectIDCompliant (PKey t124_identifier)
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{
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BOOL return_value = TRUE;
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PSetOfObjectID test_object_id_set;
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PSetOfObjectID valid_object_id_set;
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/*
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* First check to make sure that the identifier is a standard Object
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* Identifier type.
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*/
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if (t124_identifier->choice == OBJECT_CHOSEN)
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{
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/*
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* Retrieve the object identifier to test and the valid T.124
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* identifier ("t124identifier) to use as a comparison.
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*/
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test_object_id_set = t124_identifier->u.object;
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valid_object_id_set = t124identifier.u.object;
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while ((valid_object_id_set != NULL) && (test_object_id_set != NULL))
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{
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if (test_object_id_set->value != valid_object_id_set->value)
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{
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return_value = FALSE;
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break;
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}
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test_object_id_set = test_object_id_set->next;
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valid_object_id_set = valid_object_id_set->next;
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}
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}
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else
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return_value = FALSE;
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return (return_value);
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}
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void CGCCCoder::FreeEncoded (PUChar encoded_buffer)
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{
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ASN1_FreeEncoded(m_pEncInfo, encoded_buffer);
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}
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void CGCCCoder::FreeDecoded (int pdu_type, LPVOID decoded_buffer)
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{
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ASN1_FreeDecoded(m_pDecInfo, decoded_buffer, pdu_type);
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}
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