// // Copyright 2020 Electronic Arts Inc. // // TiberianDawn.DLL and RedAlert.dll and corresponding source code is free // software: you can redistribute it and/or modify it under the terms of // the GNU General Public License as published by the Free Software Foundation, // either version 3 of the License, or (at your option) any later version. // TiberianDawn.DLL and RedAlert.dll and corresponding source code is distributed // in the hope that it will be useful, but with permitted additional restrictions // under Section 7 of the GPL. See the GNU General Public License in LICENSE.TXT // distributed with this program. You should have received a copy of the // GNU General Public License along with permitted additional restrictions // with this program. If not, see https://github.com/electronicarts/CnC_Remastered_Collection /* $Header: /CounterStrike/CONNECT.H 1 3/03/97 10:24a 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 CommBufferClass 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 routines handle all ACK & Retry logic for * * communicating between this system & another. Thus, any class derived * * from this class may overload the basic ACK/Retry logic. * * * * THE PACKET 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: * * This class provides a "non-sequenced" ACK/Retry approach to packet * * transmission. It sends out as many packets as are in the queue, whose * * resend delta times have expired; and it ACK's any packets its received * * who haven't been ACK'd yet. Thus, order of delivery is NOT guaranteed; * * but, the performance is better than a "sequenced" approach. Also, the * * Packet ID scheme (see below) ensures that the application will read * * the packets in the proper order. Thus, this class guarantees delivery * * and order of deliver. * * * * Each packet has a unique numerical ID; the ID is set to a count of the * * number of packets sent. Different count values are provided, for both * * DATA_ACK & DATA_NOACK packets. This ensures that the counter can be * * used to detect resends of DATA_ACK packets; the counters for DATA_NOACK * * packets aren't currently used. Other counters keep track of the * * last-sequentially-received packet ID (for DATA_ACK packets), so we * * can check for resends & missed packets, and the last-sequentially-read * * packet ID, so we can ensure the app reads the packets in order. * * * * 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: Initialization of any hardware-specific values. * * - Send: a hardware-dependent send routine. * * * * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ #ifndef CONNECTION_H #define CONNECTION_H /* ********************************* Includes ********************************** */ #include "combuf.h" /* ********************************** Defines ********************************** */ #define CONN_DEBUG 0 /*--------------------------------------------------------------------------- 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 numsend, int numrecieve, int maxlen, unsigned short magicnum, unsigned long retry_delta, unsigned long max_retries, unsigned long timeout, int extralen = 0); virtual ~ConnectionClass (); /*..................................................................... Initialization. .....................................................................*/ virtual void Init (void); /*..................................................................... Send/Receive routines. .....................................................................*/ virtual int Send_Packet (void * buf, int buflen, int ack_req); virtual int Receive_Packet (void * buf, int buflen); virtual int Get_Packet (void * buf, int * buflen); /*..................................................................... 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); /*..................................................................... The packet "queue"; this non-sequenced version isn't really much of a queue, but more of a repository. .....................................................................*/ CommBufferClass *Queue; /* -------------------------- Protected Interface --------------------------- */ protected: /*..................................................................... Routines to service the Send & Receive queues. .....................................................................*/ virtual int Service_Send_Queue(void); virtual int Service_Receive_Queue(void); /*..................................................................... This routine actually performs a hardware-dependent data send. It's pure virtual, so it must be defined by a derived class. The routine is protected; it's only called by the ACK/Retry logic, not the application. .....................................................................*/ virtual int Send(char *buf, int buflen, void *extrabuf, int extralen) = 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; /*..................................................................... Running totals of # of packets we send & receive which require an ACK, and those that don't. .....................................................................*/ unsigned long NumRecNoAck; unsigned long NumRecAck; unsigned long NumSendNoAck; unsigned long NumSendAck; /*..................................................................... This is the ID of the last consecutively-received packet; anything older than this, we know is a resend. Anything newer than this MUST be lying around in the Queue for us to detect it as a resend. .....................................................................*/ unsigned long LastSeqID; /*..................................................................... This is the ID of the PACKET_DATA_ACK packet we read last; it ensures that the application reads that type of packet in order. .....................................................................*/ unsigned long LastReadID; /*..................................................................... Names of all packet commands .....................................................................*/ static char * Commands[PACKET_COUNT]; }; #endif /**************************** end of connect.h *****************************/