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If not, see https://github.com/electronicarts/CnC_Remastered_Collection /* $Header: F:\projects\c&c\vcs\code\connect.h_v 1.12 16 Oct 1995 16:46:04 JOE_BOSTIC $ */ /*************************************************************************** ** C O N F I D E N T I A L --- W E S T W O O D S T U D I O S ** *************************************************************************** * * * Project Name : Command & Conquer * * * * File Name : CONNECT.H * * * * Programmer : Bill Randolph * * * * Start Date : December 19, 1994 * * * * Last Update : April 1, 1995 [BR] * * * *-------------------------------------------------------------------------* * * * DESCRIPTION: * * This class represents a single "connection" with another system. It's * * a pure virtual base class that acts as a framework for other classes. * * * * This class contains a CommQueueClass member, which stores received * * & transmitted packets. The ConnectionClass has virtual functions to * * handle adding packets to the queue, reading them from the queue, * * a Send routine for actually sending data, and a Receive_Packet function * * which is used to tell the connection that a new packet has come in. * * * * The virtual Service routine will handle all ACK & Retry logic for * * communicating between this system & another. Thus, any class derived * * from this class must provide the basic ACK/Retry logic. * * * * THE HEADER: * * The Connection Classes prefix every packet sent with a header that's * * local to this class. The header contains a "Magic Number" which should * * be unique for each product, and Packet "Code", which will tell the * * receiving end if this is DATA, or an ACK packet, and a packet ID, which * * is a unique numerical ID for this packet (useful for detecting resends).* * The header is stored with each packet in the send & receive Queues; * * it's removed before it's passed back to the application, via * * Get_Packet() * * * * THE CONNECTION MANAGER: * * It is assumed that there will be a "Connection Manager" class which * * will handle parsing incoming packets; it will then tell the connection * * that new packets have come in, and the connection will process them in * * whatever way it needs to for its protocol (check for resends, handle * * ACK packets, etc). The job of the connection manager is to parse * * incoming packets & distribute them to the connections that need to * * store them (for multi-connection protocols). * * * * NOTES ON ACK/RETRY: * * The packet's ID is used to check for re-sends. The ID is set to the * * Queue's total Send Count; if the receiving system checks this value, * * and it's less than that system's Receive Count, this is a resend. * * (ie packet 0 will be the 1st packet sent, since the Send Queue's count * * is 0 when it's sent; as soon as it's received, the Receive Count goes * * up to 1, and an ID of 0 then means a resend.) This scheme keeps the * * application from seeing the same packet twice. All the Connection * * Manager has to do is mark the resent packet as non-ACK'd. Of course, * * the Manager doesn't have to use this value at all. * * * * Both DATA_ACK packets and DATA_NOACK packets must go through the Send * * Queue when "sent", so that the SendTotal value for this system * * will still match the ReceiveTotal value for the other system; this is * * why a NOACK packet can't just be sent immediately; it must go through * * the queue. * * * * If the protocol being used already guarantees delivery of packets, * * no ACK is required for the packets. In this case, the connection * * class for this protocol can overload the Service routine to avoid * * sending ACK packets, or the Connection Manager can just mark the * * packet as ACK'd when it adds it to the Receive Queue for the connection.* * * * Derived classes must provide: * * - Init a version of Init that gives the connection * * access to any hardware-specific values it needs * * Must chain to the parent's Init routine. * * - Send_Packet adds the CommHeaderType header, adds the packet * * to the out-going queue * * - Receive_Packet processes incoming ACK packets, detects resends,* * adds new packets to the in-coming queue * * - Get_Packet reads the next-available packet from the * * receive queue * * - Send the hardware-dependent data-sending routine * * - Service_Send_Queue services the send queue; handles re-sends, * * detects when outgoing packets have been ACK'd; * * cleans out the queue of old packets * * - Service_Receive_Queue services the receive queue; handles sending * * ACK's for new or re-sent packets; cleans out * * the queue of old packets * * * * Any other routines can be overloaded as the derived class needs. * * * * CLASS HIERARCHY: * * ConnectionClass * * | * * | * * -------------------------------------- * * | | * * | | * * SequencedConnClass NonSequencedConnClass * * | | * * | | * * IPXConnClass ------------------------ * * | | | * * | | | * * IPXGlobalConnClass NullModemConnClass ModemConnClass * * * * * * ConnectionClass: * * Abstract base class. * * Provides: Queue for sent/recv'd packets * * PacketBuf for preparing packets * * Timeout variables * * Service() routine * * * * SequencedConnClass: * * Abstract base class * * Provides: * "Sequenced" ACK/Retry logic, in Service_Send_Queue() & * * Service_Receive_Queue() routines * * * Send_Packet(): adds header to packet, adds it to Queue * * * Receive_Packet(): adds incoming packet to receive Queue, * * handles incoming ACK's & resends * * * Get_Packet(): gets packet from the receive queue * * * * NonSequencedConnClass: * * Abstract base class * * Provides: * "Non-Sequenced" ACK/Retry logic, in Service_Send_Queue() * * & Service_Receive_Queue() routines * * * Send_Packet(): adds header to packet, adds it to Queue * * * Receive_Packet(): adds incoming packet to receive Queue, * * handles incoming ACK's & resends * * * Get_Packet(): gets packet from the receive queue * * * * IPXConnClass: * * Provides: * Hardware-dependent IPX interface routines, which allow * * Service_Send_Queue() & Service_Receive_Queue() to do * * their job * * * Ability to associate an IPX Address, a numerical ID, and * * a character-string Name with a connection * * Inherits: * Sequenced ACK/Retry logic, Service routines, Queue & * * PacketBuf, timeout variables * * * * IPXGlobalConnClass: * * Special type of IPX Connection; supports receiving packets from * * multiple systems at once, and sending packets via Broadcast or * * to a specific address. * * Provides: * Specialized Receive_Packet() routine, which handles * * receiving packets from multiple systems * * * Specialized Send_Packet() & Get_Packet() routines, * * which pass IPX address of destination through to * * the application, giving the application control over * * whether the packet will be Broadcast or sent to a * * specific destination (embeds destination address within * * the packet itself) * * * Specialized Send routine, which extracts the destination * * address from the packet * * Inherits: * Sequenced ACK/Retry logic, Service routines, Queue & * * PacketBuf, timeout variables, IPX-specific routines * * * * NullModemConnClass: * * Provides: * Hardware-dependent Serial-communication routines, which * * allow Service_Send_Queue() & Service_Receive_Queue() to * * do their job * * Inherits: * Non-Sequenced ACK/Retry logic, Service routines, Queue & * * PacketBuf, timeout variables * * * * ModemConnClass: * * Provides: * Hardware-dependent Modem-communication routines, which * * allow Service_Send_Queue() & Service_Receive_Queue() to * * do their job * * Inherits: * Non-Sequenced ACK/Retry logic, Service routines, Queue & * * PacketBuf, timeout variables * * * * So, do ya think this header is long enough, or what? * * * * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ #ifndef CONNECTION_H #define CONNECTION_H #define CONN_DEBUG 0 /* ********************************** Defines ********************************** */ /*--------------------------------------------------------------------------- This structure is the header prefixed to any packet sent by the application. MagicNumber: This is a number unique to the application; it's up to the Receive_Packet routine to check this value, to be sure we're not getting data from some other product. This value should be unique for each application. Code: This will be one of the below-defined codes. PacketID: This is a unique numerical ID for this packet. The Connection sets this ID on all packets sent out. ---------------------------------------------------------------------------*/ typedef struct { unsigned short MagicNumber; unsigned char Code; unsigned long PacketID; } CommHeaderType; /* ***************************** Class Declaration ***************************** */ class ConnectionClass { /* ---------------------------- Public Interface ---------------------------- */ public: /*..................................................................... These are the possible values for the Code field of the CommHeaderType: .....................................................................*/ enum ConnectionEnum { PACKET_DATA_ACK, // this is a data packet requiring an ACK PACKET_DATA_NOACK, // this is a data packet not requiring an ACK PACKET_ACK, // this is an ACK for a packet PACKET_COUNT, // for computational purposes }; /*..................................................................... Constructor/destructor. .....................................................................*/ ConnectionClass (int maxlen, unsigned short magicnum, unsigned long retry_delta, unsigned long max_retries, unsigned long timeout); virtual ~ConnectionClass (); /*..................................................................... Initialization. .....................................................................*/ virtual void Init (void) {}; /*..................................................................... Send/Receive routines. .....................................................................*/ virtual int Send_Packet (void * buf, int buflen, int ack_req) = 0; virtual int Receive_Packet (void * buf, int buflen) = 0; virtual int Get_Packet (void * buf, int * buflen) = 0; /*..................................................................... The main polling routine for the connection. Should be called as often as possible. .....................................................................*/ virtual int Service (void); /*..................................................................... This routine is used by the retry logic; returns the current time in 60ths of a second. .....................................................................*/ static unsigned long Time (void); /*..................................................................... Utility routines. .....................................................................*/ unsigned short Magic_Num (void) { return (MagicNum); } unsigned long Retry_Delta (void) { return (RetryDelta); } void Set_Retry_Delta (unsigned long delta) { RetryDelta = delta;} unsigned long Max_Retries (void) { return (MaxRetries); } void Set_Max_Retries (unsigned long retries) { MaxRetries = retries;} unsigned long Time_Out (void) { return (Timeout); } void Set_TimeOut (unsigned long t) { Timeout = t;} unsigned long Max_Packet_Len (void) { return (MaxPacketLen); } static char * Command_Name(int command); /* -------------------------- Protected Interface --------------------------- */ protected: /*..................................................................... Routines to service the Send & Receive queues. .....................................................................*/ virtual int Service_Send_Queue(void) = 0; virtual int Service_Receive_Queue(void) = 0; /*..................................................................... This routine actually performs a hardware-dependent data send. It's pure virtual, so it >must< be defined by a derived class. .....................................................................*/ virtual int Send(char *buf, int buflen) = 0; /*..................................................................... This is the maximum packet length, including our own internal header. .....................................................................*/ int MaxPacketLen; /*..................................................................... Packet staging area; this is where the CommHeaderType gets tacked onto the application's packet before it's sent. .....................................................................*/ char *PacketBuf; /*..................................................................... This is the magic number assigned to this connection. It is the first few bytes of any transmission. .....................................................................*/ unsigned short MagicNum; /*..................................................................... This value determines the time delay before a packet is re-sent. .....................................................................*/ unsigned long RetryDelta; /*..................................................................... This is the maximum number of retries allowed for a packet; if this value is exceeded, the connection is probably broken. .....................................................................*/ unsigned long MaxRetries; /*..................................................................... This is the total timeout for this connection; if this time is exceeded on a packet, the connection is probably broken. .....................................................................*/ unsigned long Timeout; /*..................................................................... Names of all packet commands .....................................................................*/ static char *ConnectionClass::Commands[PACKET_COUNT]; }; #endif