//
// Copyright 2020 Electronic Arts Inc.
//
// TiberianDawn.DLL and RedAlert.dll and corresponding source code is free
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// TiberianDawn.DLL and RedAlert.dll and corresponding source code is distributed
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// 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
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/* $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 *****************************/