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/* T123.h
* * Copyright (c) 1993-1995 by DataBeam Corporation, Lexington, KY * * Abstract: * This class controlls the T123 stack associated with a particular * physical connection. * * This class builds a T123 PSTN stack. The physical layer is passed in via * the constructor. During the constructor, we instantiate a multiplexer. * This multiplexer will allow us to mux multiple DataLink layers to the * same physical address. For this particular physical connection (PSTN) * the Multiplexer adds a CRC to the packet and frames it before passing * it to the physical layer. On the receive side, it frames the incoming * stream data and packetizes it. It also checks the CRC for validity. * The Multiplexer receives data from its higher layer * (DataLink) in packet form. When the Multiplexer passes data to its * lower layer, it passes it in stream form. The Multiplexer is * configured to be a multi-DataLink entity. Since it does handle multiple * DataLinks, it can NOT buffer data on the receive side. If one * particular DataLink is backed up, it can NOT hold the other DataLinks * up. If it can not pass a packet up immediately, it will trash it. * * After the Multiplexer issues a callback to us to us it is ready, we * will create a DataLink Layer to service the Network layer. The DataLink * Layer is based on the Q.922 standard. The DLCI associated with this * DataLink is 0. Its Lower Layer is the Multiplexer. Its Higher Layer is * the SCF Layer. * * The SCF Layer is the Network Layer. It is responsible for * arbitrating the DLCI and parameters used in other transport * connections. It has no responsibilities once the connection is up. If * this class receives a ConnectRequest() from the user, it issues a * ConnectRequest() to the SCF Layer. SCF will notify us when the * connection is up. * * When the SCF notifies us that a new connection exists, we create a * DataLink Layer that services the new Transport Connection. This * DataLink Layer uses our Multiplexer as its Lower Layer. * * When the DataLink Layer is up and operational, it notifies us. At this * point, we create an X224 Layer to interface with the user. The X224 * Layer interfaces with the DataLink Layer to send data. It also * interfaces with the user to pass data on up. * * Caveats: * None. * * Author: * James W. Lawwill */#ifndef _T123_H_
#define _T123_H_
#include "scf.h"
#include "q922.h"
#include "mplex.h"
#include "x224.h"
/*
** Layer Numbers */#define PHYSICAL_LAYER 1
#define MULTIPLEXER_LAYER 2 // This is a DataBeam-specific layer
#define DATALINK_LAYER 3
#define NETWORK_LAYER 4
#define TRANSPORT_LAYER 5
/*
** Layer Message Bases */#define PHYSICAL_LAYER_MESSAGE_BASE 0x0000
#define MULTIPLEXER_LAYER_MESSAGE_BASE 0x1000
#define DATALINK_LAYER_MESSAGE_BASE 0x2000
#define NETWORK_LAYER_MESSAGE_BASE 0x3000
#define TRANSPORT_LAYER_MESSAGE_BASE 0x4000
#define LAYER_MASK 0x7000
#define MESSAGE_MASK 0x0fff
/*
** Maximum number of priorities */// #define NUMBER_OF_PRIORITIES 15
#define NUMBER_OF_PRIORITIES 4
#define LOWEST_DLCI_VALUE 16
#define HIGHEST_DLCI_VALUE 991
#define INVALID_LOGICAL_HANDLE 0
/*
** Each DLCI has this structure associated with it. */typedef struct{ BOOL link_originator; CLayerX224 *x224; // transport_layer
CLayerQ922 *q922; // datalink_layer
TransportPriority priority; BOOL disconnect_requested; BOOL connect_requested; PMemoryManager data_request_memory_manager; USHORT network_retries;} DLCIStruct, *PDLCIStruct;
class T123{public:
T123(TransportController *owner_object, USHORT message_base, BOOL link_originator, ComPort *physical_layer, PhysicalHandle physical_handle, PLUGXPRT_PARAMETERS *pParams, BOOL * t123_initialized);
virtual ~T123(void);
/*
** Functions related to making and breaking a linkg */ TransportError ConnectRequest ( LogicalHandle logical_handle, TransportPriority priority); TransportError ConnectResponse ( LogicalHandle logical_handle); TransportError DisconnectRequest ( LogicalHandle logical_handle, UINT_PTR trash_packets); TransportError DataRequest ( LogicalHandle logical_handle, LPBYTE user_data, ULONG user_data_length); TransportError PurgeRequest ( LogicalHandle logical_handle); void EnableReceiver (void);
ULONG PollReceiver (void); void PollTransmitter (void);
ULONG OwnerCallback(ULONG, void *p1 = NULL, void *p2 = NULL, void *p3 = NULL);
private:
void Reset (void); DLCI GetNextDLCI (void); void ProcessMessages (void); void NetworkDisconnectIndication ( DLCI dlci, BOOL link_originator, BOOL retry); void DataLinkRelease ( DLCI dlci, DataLinkDisconnectType error); void NewConnection (void); void NetworkConnectIndication ( PNetworkConnectStruct connect_struct); void NetworkConnectConfirm ( PNetworkConnectStruct connect_struct); void DataLinkEstablish ( DLCI dlci);private:
BOOL m_fValidSDKParams; PLUGXPRT_PARAMETERS m_SDKParams;
DictionaryClass Logical_Connection_List; DictionaryClass DLCI_List; SListClass Message_List; SListClass DataLink_List; SListClass *Logical_Connection_Priority_List[NUMBER_OF_PRIORITIES]; TransportController *m_pController; BOOL Link_Originator; USHORT m_nMsgBase;
CLayerSCF *m_pSCF; // network layer
CLayerQ922 *m_pQ922; // data link layer
Multiplexer *m_pMultiplexer; // multiplexer layer
ComPort *m_pComPort; // physical layer
PhysicalHandle m_hCommLink; DataLinkParameters DataLink_Struct; PMemoryManager Data_Request_Memory_Manager;#ifdef USE_RANDOM_CLASS
PRandomNumberGenerator Random;#endif
BOOL Disconnect_Requested;};typedef T123 * PT123;
#endif
/*
* Documentation for Public class members */
/*
* T123::T123 ( * PTransportResources transport_resources, * IObject * owner_object, * USHORT message_base, * BOOL link_originator, * IProtocolLayer * physical_layer, * PhysicalHandle physical_handle, * BOOL * initialized); * * Functional Description * This is the constructor for the T123 class. It prepares for new * connections. * * Formal Parameters * transport_resources (i) - Address of resources structure. * owner_object (i) - Address of owner object. Used for owner * callbacks. * message_base (i) - Message base used with owner callbacks. * link_originator (i) - TRUE if we actually originated the * connection * physical_layer (i) - Pointer to physical layer * physical_handle (i) - Identifier that needs to be passed to the * physical layer to identify the connection * initialized (o) - TRUE if the object initialized OK. * * Return Value * None * * Side Effects * None * * Caveats * None */
/*
* T123::~T123 (void) * * Functional Description * This is the T123 destructor. It removes all active connections * * Formal Parameters * None * * Return Value * None * * Side Effects * None * * Caveats * None * */
/*
* TransportError T123::ConnectRequest ( * LogicalHandle logical_handle * TransportPriority priority); * * Functional Description * This function initiates a logical connection. * * Formal Parameters * logical_handle (i) - Handle assocaiated with the * logical connection * priority (i) - Requested priority of the connection. * * Return Value * TRANSPORT_NO_ERROR - No Error * * Side Effects * None * * Caveats * None */
/*
* TransportError T123::ConnectResponse ( * LogicalHandle logical_handle) * * Functional Description * This function is called in response to TRANSPORT_CONNECT_INDICATION * message that was sent the owner. By making this call, the owner is * accepting the connection. * * Formal Parameters * logical_handle (i) - Logical connection handle * * Return Value * TRANSPORT_NO_ERROR - No Error * TRANSPORT_CONNECT_RESPONSE_FAILURE - Function not valid * * Side Effects * None * * Caveats * None */
/*
* TransportError T123::DisconnectRequest ( * LogicalHandle logical_handle, * BOOL trash_packets); * * Functional Description * This function terminates the transport connection. The user will * receive a TRANSPORT_DISCONNECT_INDICATION message when the connection * is terminated * * If the logical_handle equals INVALID_LOGICAL_HANDLE, the user is * telling us to take down all logical connections and ultimately the * physical connection. * * Formal Parameters * logical_handle - (i) Logical connection number to terminate * trash_packets - (i) BOOL , set to TRUE if we are to trash * the packets in the output buffer. * * Return Value * TRANSPORT_NO_ERROR - No Error * TRANSPORT_NO_SUCH_CONNECTION - Transport connection does not exist * * Side Effects * None * * Caveats * None */
/*
* TransportError T123::DataRequest ( * LogicalHandle logical_handle, * LPBYTE user_data, * ULONG user_data_length); * * Functional Description * This function is used to send a data packet to the remote location. * We simply pass this packet to the X224 object associated with the * transport connection. * * Formal Parameters * logical_handle - (i) Transport connection number * user_data - (i) Address of data to send * user_data_length - (i) Length of data to send * * Return Value * TRANSPORT_NO_ERROR - No Error * TRANSPORT_NO_SUCH_CONNECTION - Logical connection does not exist * TRANSPORT_WRITE_QUEUE_FULL - Transport write queues are already * full. * TRANSPORT_NOT_READY_TO_TRANSMIT - The transport layer is in the * process of building or breaking * down the transport stack and is * not ready for user data. * * Side Effects * None * * Caveats * None */
/*
* TransportError T123::PurgeRequest ( * LogicalHandle logical_handle) * * Functional Description * This function purges the outbound packets for the logical connection. * * Formal Parameters * logical_handle - (i) Transport connection number * * Return Value * TRANSPORT_NO_ERROR - No Error * TRANSPORT_NO_SUCH_CONNECTION - Logical connection does not exist * * Side Effects * None */
/*
* TransportError T123::EnableReceiver (void); * * Functional Description * This function is called to enable TRANSPORT_DATA_INDICATION callbacks * to the user application. * * Formal Parameters * None. * * Return Value * TRANSPORT_NO_ERROR - No Error * * Side Effects * None */
/*
* void T123::PollReceiver (void); * * Functional Description * This function gives the T123 stack a chance to receive packets from * the remote site. During this call, we may be making user callbacks to * pass the data on up. * * Formal Parameters * None. * * Return Value * None. * * Side Effects * None * * Caveats * None */
/*
* void T123::PollTransmitter (void); * * Functional Description * This function gives the T123 stack a chance to transmit data to the * remote site. * * Formal Parameters * None. * * Return Value * None. * * Side Effects * None * * Caveats * None */
/*
* ULONG T123::OwnerCallback ( * USHORT layer_message, * ULONG parameter1, * ULONG parameter2, * PVoid parameter3); * * Functional Description * This function is the owner callback function. If any of the layers * owned by this object want to send us a message, they make an owner * callback. During instantiation of these lower layers, we pass them our * address. They can call us with significant messages. * * Formal Parameters * layer_message (i) - Layer-specific message * parameter1 (i) - Message-specific parameter * parameter2 (i) - Message-specific parameter * parameter3 (i) - Message-specific parameter * * Return Value * Message specific * * Side Effects * None * * Caveats * None */
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