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WindowsXP-SP1/enduser/netmeeting/t120/mst123/x224.h
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/* X224.h
*
* Copyright (c) 1994-1995 by DataBeam Corporation, Lexington, KY
*
* Abstract:
* This class represents the X.224 class 0 Transport functionality. This
* is the highest layer in the T.123 specification. This layer is unique
* in that it has direct access to the User. When data packets are
* received from the remote site and reassembled by this class, they are
* passed on to the user via a callback.
*
* This class has only limited functionality. It basically has a simple
* link establishment procedure (which includes arbitration of maximum PDU
* size). It is then responsible for transmitting and receiving user data.
* Its maximum TSDU size is 8K, and its TPDU size can range from 128 bytes
* to 2K. Its TSDU size is larger than its TPDU size, it must be able to
* segment and reassemble the user packet.
*
* This layer ASSUMES that its lower layer has a packet interface rather
* than a stream interface.
*
* This layer ASSUMES that the disconnect of a call is handled by the
* Network layer (as specified in the X.224 class 0 document).
*
* Prior knowledge of the X.224 class 0 specification would help the user
* understand the code.
*
* Caveats:
* None.
*
* Authors:
* James W. Lawwill
*/
#ifndef _X224_H_
#define _X224_H_
#include "tmemory2.h"
/*
** The following, are states that the class can be in.
*/
typedef enum
{
NO_CONNECTION,
SENT_CONNECT_REQUEST_PACKET,
SENT_CONNECT_CONFIRM_PACKET,
SENT_DISCONNECT_REQUEST_PACKET,
SENT_ERROR_PACKET,
CONNECTION_ACTIVE,
RECEIVED_CONNECT_REQUEST_PACKET,
FAILED_TO_INITIALIZE
}
X224State;
#define TRANSPORT_HASHING_BUCKETS 3
/*
** Packet types
*/
#define TPDU_CODE_MASK 0xf0
#define TRANSPORT_NO_PACKET 0x00
#define CONNECTION_REQUEST_PACKET 0xe0
#define CONNECTION_CONFIRM_PACKET 0xd0
#define DISCONNECT_REQUEST_PACKET 0x80
#define ERROR_PACKET 0x70
#define DATA_PACKET 0xf0
#define TSAP_CALLING_IDENTIFIER 0xc1
#define TSAP_CALLED_IDENTIFIER 0xc2
#define TPDU_SIZE 0xc0
/*
** These defines are used for the ERROR packet
*/
#define INVALID_TPDU 0xc1
/*
** Packet size codes
*/
#define PACKET_SIZE_128 0x07
#define PACKET_SIZE_256 0x08
#define PACKET_SIZE_512 0x09
#define PACKET_SIZE_1024 0x0a
#define PACKET_SIZE_2048 0x0b
/*
** Miscellaneous definitions
*/
#define MAXIMUM_USER_DATA_SIZE 8192
#define DATA_PACKET_HEADER_SIZE 3
#define EOT_BIT 0x80
#define CONNECT_REQUEST_HEADER_SIZE 6
#define CONNECT_CONFIRM_HEADER_SIZE 6
#define DISCONNECT_REQUEST_HEADER_SIZE 6
#define ERROR_HEADER_SIZE 6
#define TPDU_ARBITRATION_PACKET_SIZE 3
#define DISCONNECT_REASON_NOT_SPECIFIED 0
typedef SListClass DataRequestQueue;
typedef SListClass PacketQueue;
class CLayerX224 : public IProtocolLayer
{
public:
CLayerX224(
T123 *owner_object,
CLayerQ922 *lower_layer,
USHORT message_base,
LogicalHandle logical_handle,
ULONG identifier,
USHORT data_indication_queue_size,
USHORT default_PDU_size,
PMemoryManager dr_memory_manager,
BOOL *initialization_success);
virtual ~CLayerX224(void);
/*
** Making and breaking links
*/
TransportError ConnectRequest (void);
TransportError ConnectResponse (void);
TransportError DisconnectRequest (void);
/*
** Functions overridden from the ProtocolLayer object
*/
ProtocolLayerError DataRequest (
ULONG_PTR identifier,
LPBYTE buffer_address,
ULONG length,
PULong bytes_accepted);
ProtocolLayerError DataRequest (
ULONG_PTR identifier,
PMemory,
PULong bytes_accepted);
ProtocolLayerError DataIndication (
LPBYTE buffer_address,
ULONG length,
PULong bytes_accepted);
ProtocolLayerError RegisterHigherLayer (
ULONG_PTR,
PMemoryManager,
IProtocolLayer *);
ProtocolLayerError RemoveHigherLayer (
ULONG_PTR);
ProtocolLayerError PollTransmitter (
ULONG_PTR identifier,
USHORT data_to_transmit,
USHORT * pending_data,
USHORT * holding_data);
ProtocolLayerError PollReceiver(void);
ProtocolLayerError GetParameters (
USHORT *,
USHORT *,
USHORT *);
void ShutdownReceiver (void);
void EnableReceiver (void);
void ShutdownTransmitter (void);
void PurgeRequest (void);
void CheckUserBuffers (void);
static ULONG GetMaxTPDUSize (
ULONG max_lower_layer_pdu);
private:
BOOL AllocateBuffers (void);
void ErrorPacket (
LPBYTE packet_address,
USHORT packet_length);
private:
DataRequestQueue Data_Request_Queue;
PacketQueue Data_Indication_Queue;
PacketQueue Data_Indication_Memory_Pool;
PTMemory Active_Data_Indication;
T123 *m_pT123; // owner object
CLayerQ922 *m_pQ922; // lower layer;
USHORT m_nMsgBase;
USHORT Default_PDU_Size;
USHORT Maximum_PDU_Size;
USHORT Arbitrated_PDU_Size;
ULONG Identifier;
PMemoryManager Data_Request_Memory_Manager;
USHORT Lower_Layer_Prepend;
USHORT Lower_Layer_Append;
ULONG User_Data_Pending;
USHORT Data_Indication_Queue_Size;
BOOL Data_Indication_Reassembly_Active;
X224State State;
USHORT Packet_Pending;
UChar Reject_Cause;
BOOL Packet_Size_Respond;
BOOL Shutdown_Receiver;
BOOL Shutdown_Transmitter;
LPBYTE Error_Buffer;
USHORT Error_Buffer_Length;
LogicalHandle m_nLocalLogicalHandle;
LogicalHandle m_nRemoteLogicalHandle;
};
#endif
/*
* Documentation for Public class members
*/
/*
* Transport::Transport (
* PTransportResources transport_resources,
* IObject * owner_object,
* IProtocolLayer * lower_layer,
* USHORT message_base,
* USHORT logical_handle,
* USHORT identifier,
* USHORT data_request_queue_size,
* USHORT data_indication_queue_size,
* USHORT default_PDU_size,
* PMemoryManager dr_memory_manager,
* BOOL * initialization_success);
*
* Functional Description
* This is the class constructor. During construction, this object
* registers itself with its lower layer and allocates buffer space for
* sending and receiving data.
*
* Formal Parameters
* transport_resources (i) - Pointer to TransportResources structure.
* owner_object (i) - Address of owner object. We use this
* address for owner callbacks.
* lower_layer (i) - Address of the lower layer that we will use
* for data reception and transmission. This
* layer must inherit from ProtocolLayer.
* message_base (i) - Message base for messages used for owner
* callbacks.
* logical_handle (i) - This identification must be passed back to
* the owner during owner callbacks to identify
* itself.
* identifier (i) - This identifier is passed to the lower layer
* to identify itself (in case the lower layer
* is doing multiplexing.
* data_request_queue_size (i) - Number of buffers to be used for data
* requests from user.
* data_indication_queue_size (i) - Number of buffers to be used for
* data requests from user.
* default_PDU_size (i) - If the remote site does not support packet
* size arbitration, this is the default
* dr_memory_manager (i) - Data Request memory manager
* initialization_success (o) - Return TRUE if initialization was
* successful
*
* Return Value
* None
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* Transport::~Transport (void)
*
* Functional Description
* This is the destructor for the class. It does all cleanup
*
* Formal Parameters
* None
*
* Return Value
* None
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* TransportError Transport::ConnectRequest (void);
*
* Functional Description
* This function is called to initiate the connection. As a result the
* owner will either receive a TRANSPORT_CONNECT_CONFIRM or a
* TRANSPORT_DISCONNECT_INDICATION message on completion of arbitration.
*
* Formal Parameters
* None
*
* Return Value
* TRANSPORT_NO_ERROR - No error occured
* TRANSPORT_ERROR - Error
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* TransportError Transport::ConnectResponse (void);
*
* Functional Description
* This function is called in response to a TRANSPORT_CONNECT_INDICATION
* message issued by this class. By calling this function, the user is
* accepting the transport connection.
*
* Formal Parameters
* None
*
* Return Value
* TRANSPORT_NO_ERROR - No error occured
* TRANSPORT_ERROR - Error
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* TransportError Transport::DisconnectRequest (void);
*
* Functional Description
* This function is called in response to a TRANSPORT_CONNECT_INDICATION
* message issued by this class. By calling this function, the user is
* not accepting the transport connection.
*
* Formal Parameters
* None
*
* Return Value
* TRANSPORT_NO_ERROR - No error occured
* TRANSPORT_ERROR - Error
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* ProtocolLayerError Transport::DataRequest (
* USHORT identifier,
* LPBYTE buffer_address,
* USHORT length,
* USHORT * bytes_accepted);
*
* Functional Description
* This function is called by a higher layer to request transmission of
* a packet.
*
* Formal Parameters
* identifier (i) - Identifier of the higher layer
* buffer_address (i) - Buffer address
* length (i) - Length of packet to transmit
* bytes_accepted (o) - Number of bytes accepted by the Transport.
* This value will either be 0 or the packet
* length since this layer is a packet to byte
* converter.
*
* Return Value
* PROTOCOL_LAYER_NO_ERROR - No error occured
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* ProtocolLayerError Transport::DataIndication (
* LPBYTE buffer_address,
* USHORT length,
* USHORT * bytes_accepted);
*
* Functional Description
* This function is called by the lower layer when it has data to pass up
*
* Formal Parameters
* buffer_address (i) - Buffer address
* length (i) - Number of bytes available
* bytes_accepted (o) - Number of bytes accepted
*
* Return Value
* PROTOCOL_LAYER_NO_ERROR - No error occured
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* ProtocolLayerError Transport::RegisterHigherLayer (
* USHORT,
* IProtocolLayer *);
*
* Functional Description
* This function is called by the higher layer to register its identifier
* and its address. This function is not used by this class. It is only
* in here because this class inherits from ProtocolLayer and this function
* is a pure virtual function.
*
* Formal Parameters
* None used
*
* Return Value
* PROTOCOL_LAYER_NO_ERROR - No error occured
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* ProtocolLayerError Transport::RemoveHigherLayer (
* USHORT);
*
* Functional Description
* This function is called by the higher layer to remove its identifier
* and its address. This function is not used by this class. It is only
* in here because this class inherits from ProtocolLayer and this function
* is a pure virtual function.
*
* Formal Parameters
* None used
*
* Return Value
* PROTOCOL_LAYER_NO_ERROR - No error occured
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* ProtocolLayerError Transport::PollTransmitter (
* USHORT,
* USHORT data_to_transmit,
* USHORT * pending_data,
* USHORT *)
*
* Functional Description
* This function is called to give the Transport a chance transmit data
* in its Data_Request buffer.
*
* Formal Parameters
* identifier (i) - Not used
* data_to_transmit (i) - This is a mask that tells us to send Control
* data, User data, or both. Since the
* Transport does not differentiate between
* data types it transmits any data it has
* pending_data (o) - Return value to indicate which data is left
* to be transmitted.
*
* Return Value
* PROTOCOL_LAYER_NO_ERROR - No error occured
*
* Side Effects
* None
*
* Caveats
* None
*
*/
/*
* ProtocolLayerError Transport::PollReceiver (
* USHORT identifier);
*
* Functional Description
* This function is called to give the Transport a chance pass packets
* to higher layers
*
* Formal Parameters
* identifier (i) - Not used
*
* Return Value
* PROTOCOL_LAYER_NO_ERROR - No error occured
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* ProtocolLayerError Transport::GetParameters (
* USHORT identifier,
* USHORT * max_packet_size,
* USHORT * prepend,
* USHORT * append);
*
* Functional Description:
* This function is not used by this class. It is only in here because
* this class inherits from ProtocolLayer and this function
* is a pure virtual function.
*
* Formal Parameters
* None used
*
* Return Value
* PROTOCOL_LAYER_NO_ERROR - No error occured
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* void Transport::ShutdownReceiver ();
*
* Functional Description:
* This function tells the object to stop accepting packets from the
* lower layer
*
* Formal Parameters
* None used
*
* Return Value
* None
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* void Transport::EnableReceiver (void);
*
* Functional Description:
* This function tells the object to start sending packets up to the user
* again. If the X224 object ever issues a DATA_INDICATION and it fails,
* we shutdown the receiver. We wait for this call to be issued before
* we start sending up packets again.
*
* Formal Parameters
* None used
*
* Return Value
* None
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* void Transport::ShutdownTransmitter (void);
*
* Functional Description:
* This function tells the object to stop accepting packets from
* higher layers.
*
* Formal Parameters
* None used
*
* Return Value
* None
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* void Transport::PurgeRequest (void);
*
* Functional Description:
* This function removes all packets from the Transport's outbound queue
*
* Formal Parameters
* None used
*
* Return Value
* None
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* void Transport::CheckUserBuffers (void);
*
* Functional Description:
* This function determines if the user has recently failed to pass a
* packet down to the Transport because we didn't have enough memory
* available to handle it. If he did and we NOW have space for that
* packet, we will issue a TRANSPORT_BUFFER_EMPTY_INDICATION callback
* to the user, to notify him that we can accept it.
*
* Formal Parameters
* None used
*
* Return Value
* None
*
* Side Effects
* None
*
* Caveats
* None
*/
/*
* static ULONG Transport::GetMaxTPDUSize (
* ULONG max_lower_layer_pdu)
*
* Public
*
* Functional Description:
* This function accepts a value for the lower layer max. PDU size
* and returns the max. PDU size that this Transport can support
* based on it. X224 only suports max PDU sizes of 128, 256, 512,
* 1024, and 2048. So, if the max_lower_layer_pdu is 260, the
* Transport can only have a max pdu size of 256.
*
* Formal Parameters
* max_lower_layer_pdu - Since we pass data to the lower layer,
* we must conform to its max packet size.
*
* Return Value
* The largest TPDU that we will send based on the max_lower_layer_pdu.
*
* Side Effects
* None
*
* Caveats
* None
*/

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