292 lines
8.3 KiB
C
292 lines
8.3 KiB
C
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/*
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* packet.h
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*
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* Copyright (c) 1993 - 1995 by DataBeam Corporation, Lexington, KY
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* 1997 by Microsoft Corporation, Redmond, WA
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*
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* Abstract:
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* This is the interface file for the Packet class. Instances of this
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* class represent Protocol Data Units (PDUs) as they flow through the
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* system. These instances manage the memory required to hold both
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* encoded and decoded versions of the PDU, and make sure that no PDU
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* is ever encoded or decoded more than once. The use of lock counts
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* allow multiple objects in the system to reference and use the same
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* packet object at the same time. This class inherits from the SimplePacket
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* class (a pure virtual class).
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*
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* A packet object can be created in 2 different ways. It can be created
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* with either decoded data or encoded data. During instantiation, the
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* new packet object will calculate how much memory it will need to
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* hold both the encoded and decoded data, and attempts to allocate that
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* memory. If it cannot, then it will report an error, and the newly
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* created object should be immediately destroyed. If the allocations are
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* successful, then the packet will report success, but WILL NOT yet put
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* any data into those allocated buffers.
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*
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* When a Lock message is sent to the object, it will put encoded
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* data into the pre-allocated encode buffer. If the packet was created
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* with decoded data, then this will entail an encode operation. However,
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* if the packet was created with encoded data, then it is smart enough
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* to just COPY the encoded data into the internal buffer, thus avoiding
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* the overhead associated with the encode operation.
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*
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* When a Lock message is sent to the object, it will put decoded
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* data into the pre-allocated decode buffer. If the packet was created
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* with encoded data, then this will entail a decode operation. However,
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* if the packet was created with decoded data, then it is smart enough
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* to just COPY the decoded data into the internal buffer, thus avoiding
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* the overhead associated with the decode operation.
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*
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* When Unlock messages are received, the lock count is decremented. When
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* the lock count is 0, the packet deletes itself (it commits
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* suicide). Note that for this reason, no other object should explicitly
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* delete a packet object.
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*
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* Caveats:
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* None.
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*
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* Authors:
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* James J. Johnstone IV
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* Christos Tsollis
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*/
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#ifndef _PACKET_
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#define _PACKET_
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#include "pktcoder.h"
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/*
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* Definition of class Packet.
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*/
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class Packet;
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typedef Packet * PPacket;
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class Packet : public SimplePacket
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{
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public:
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// outgoing packets
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Packet(PPacketCoder pPacketCoder,
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UINT nEncodingRules,
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LPVOID pInputPduStructure,
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int nPduType,
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BOOL fPacketDirectionUp,
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PPacketError pePktErr,
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BOOL fLockEncodedData = FALSE);
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// incoming packets
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Packet(PPacketCoder pPacketCoder,
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UINT nEncodingRules,
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LPBYTE pEncodedData,
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UINT cbEncodedDataSize,
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int nPduType,
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BOOL fPacketDirectionUp,
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PPacketError pePktErr);
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virtual ~Packet(void);
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virtual BOOL IsDataPacket (void);
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virtual PVoid GetDecodedData(void);
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UINT GetDecodedDataLength(void) { return Decoded_Data_Length; };
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virtual int GetPDUType(void);
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protected:
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PPacketCoder Packet_Coder;
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LPVOID m_Decoded_Data;
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UINT Decoded_Data_Length;
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int PDU_Type;
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};
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/*
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* Packet (
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* PPacketCoder packet_coder,
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* UINT encoding_rules,
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* PVoid pInputPduStructure,
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* PMemory pInputPduStructure_Memory,
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* int pdu_type,
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* DBBoolean packet_direction_up,
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* PPacketError return_value )
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*
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* Functional Description:
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* This version of the constructor is used to create a Packet object
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* for outgoing PDUs when the packet is to be created from a structure
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* containing the PDU data to be encoded.
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*
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* Formal Parameters:
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* packet_coder (i)
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* Pointer to the packet coder object. This pointer will be used by
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* the packet object to encode and decode PDU structures. This pointer
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* must not become stale during the life of the packet object.
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* encoding_rules (i)
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* This value identifies which set of encoding rules should be used
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* on the current packet. This is simply through to the packet coder
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* during all encode and decode operations.
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* pInputPduStructure (i)
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* Pointer to the input PDU structure.
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* pInputPduStructure_Memory
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* Pointer to a Memory struct for the buffer containing the pdu structure.
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* Exactly one of the args pInputPduStructure_Memory and pInputPduStructure
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* should be non-NULL;
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* pdu_type (i)
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* The type of PDU contained in the packet. This is passed through
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* to the packet coder specified above.
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* packet_direction_up (i)
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* The packet_direction_up flag indicates the initial orientation of
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* the packet. Valid values are:
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* TRUE - The packet's direction is up.
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* FALSE - The packet's direction is down.
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* return_value (o)
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* When the constructor returns control to the calling function, this
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* variable will be set to one of the return values listed below.
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*
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* Return Value:
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* PACKET_NO_ERROR
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* The Packet object was constructed correctly.
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* PACKET_MALLOC_FAILURE
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* The constructor was unable to allocate the memory required to work
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* properly. The Packet object should be deleted.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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/*
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* Packet (
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* PPacketCoder packet_coder,
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* UINT encoding_rules,
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* PUChar encoded_data_ptr,
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* UShort encoded_data_length,
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* int pdu_type,
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* DBBoolean packet_direction_up,
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* PPacketError return_value )
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*
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* Functional Description:
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* This version of the constructor is used to create a Packet object
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* for incomming PDUs when the packet is to be created from an encoded
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* data stream containing the PDU data to be decoded.
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*
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* Formal Parameters:
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* packet_coder (i)
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* Pointer to the packet coder object. This pointer will be used by
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* the packet object to encode and decode PDU structures. This pointer
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* must not become stale during the life of the packet object.
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* encoding_rules (i)
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* This value identifies which set of encoding rules should be used
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* on the current packet. This is simply through to the packet coder
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* during all encode and decode operations.
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* encoded_data_ptr (i)
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* Pointer to the input encoded PDU.
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* encoded_data_length (i)
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* The length in bytes of the input encoded PDU.
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* pdu_type (i)
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* The type of PDU contained in the packet. This is passed through
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* to the packet coder specified above.
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* packet_direction_up (i)
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* The packet_direction_up flag indicates the initial orientation of
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* the packet. Valid values are:
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* TRUE - The packet's direction is up.
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* FALSE - The packet's direction is down.
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* return_value (o)
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* When the constructor returns control to the calling function, this
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* variable will be set to one of the return values listed below.
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*
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* Return Value:
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* PACKET_NO_ERROR
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* The Packet object was constructed correctly.
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* PACKET_MALLOC_FAILURE
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* The constructor was unable to allocate the memory required to work
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* properly. The Packet object should be deleted.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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/*
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* ~Packet ()
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*
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* Functional Description:
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* Destructor for the Packet class. The destructor ensures that all
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* resources that have been allocated are freed.
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*
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* Formal Parameters:
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* None.
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*
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* Return Value:
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* None.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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/*
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* GetDecodedData ()
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*
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* Functional Description:
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* The GetDecodedData method returns a pointer to the decoded data
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* buffer.
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*
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* Formal Parameters:
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* None.
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*
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* Return Value:
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* A pointer to the decoded data. If an decoding error occurs, this
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* method will return NULL.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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/*
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* GetDecodedDataLength ()
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*
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* Functional Description:
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* This method returns the decoded data's length.
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*
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* Formal Parameters:
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* None.
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*
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* Return Value:
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* The number of bytes in the decoded data.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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/*
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* GetPDUType ()
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*
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* Functional Description:
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* This method returns the PDU type.
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*
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* Formal Parameters:
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* None.
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*
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* Return Value:
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* Either DOMAIN_MCS_PDU or CONNECT_MCS_PDU dependant upon the PDU type.
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*
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* Side Effects:
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* None.
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*
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* Caveats:
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* None.
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*/
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#endif
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