343 lines
17 KiB
C++
343 lines
17 KiB
C++
/*
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** Command & Conquer(tm)
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** Copyright 2025 Electronic Arts Inc.
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**
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** This program is free software: you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation, either version 3 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/* $Header: F:\projects\c&c\vcs\code\connect.h_v 1.12 16 Oct 1995 16:46:04 JOE_BOSTIC $ */
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/***************************************************************************
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** 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 **
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***************************************************************************
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* *
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* Project Name : Command & Conquer *
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* *
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* File Name : CONNECT.H *
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* *
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* Programmer : Bill Randolph *
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* *
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* Start Date : December 19, 1994 *
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* *
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* Last Update : April 1, 1995 [BR] *
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* *
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*-------------------------------------------------------------------------*
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* *
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* DESCRIPTION: *
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* This class represents a single "connection" with another system. It's *
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* a pure virtual base class that acts as a framework for other classes. *
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* *
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* This class contains a CommQueueClass member, which stores received *
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* & transmitted packets. The ConnectionClass has virtual functions to *
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* handle adding packets to the queue, reading them from the queue, *
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* a Send routine for actually sending data, and a Receive_Packet function *
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* which is used to tell the connection that a new packet has come in. *
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* *
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* The virtual Service routine will handle all ACK & Retry logic for *
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* communicating between this system & another. Thus, any class derived *
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* from this class must provide the basic ACK/Retry logic. *
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* *
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* THE HEADER: *
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* The Connection Classes prefix every packet sent with a header that's *
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* local to this class. The header contains a "Magic Number" which should *
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* be unique for each product, and Packet "Code", which will tell the *
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* receiving end if this is DATA, or an ACK packet, and a packet ID, which *
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* is a unique numerical ID for this packet (useful for detecting resends).*
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* The header is stored with each packet in the send & receive Queues; *
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* it's removed before it's passed back to the application, via *
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* Get_Packet() *
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* *
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* THE CONNECTION MANAGER: *
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* It is assumed that there will be a "Connection Manager" class which *
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* will handle parsing incoming packets; it will then tell the connection *
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* that new packets have come in, and the connection will process them in *
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* whatever way it needs to for its protocol (check for resends, handle *
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* ACK packets, etc). The job of the connection manager is to parse *
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* incoming packets & distribute them to the connections that need to *
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* store them (for multi-connection protocols). *
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* *
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* NOTES ON ACK/RETRY: *
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* The packet's ID is used to check for re-sends. The ID is set to the *
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* Queue's total Send Count; if the receiving system checks this value, *
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* and it's less than that system's Receive Count, this is a resend. *
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* (ie packet 0 will be the 1st packet sent, since the Send Queue's count *
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* is 0 when it's sent; as soon as it's received, the Receive Count goes *
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* up to 1, and an ID of 0 then means a resend.) This scheme keeps the *
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* application from seeing the same packet twice. All the Connection *
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* Manager has to do is mark the resent packet as non-ACK'd. Of course, *
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* the Manager doesn't have to use this value at all. *
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* *
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* Both DATA_ACK packets and DATA_NOACK packets must go through the Send *
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* Queue when "sent", so that the SendTotal value for this system *
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* will still match the ReceiveTotal value for the other system; this is *
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* why a NOACK packet can't just be sent immediately; it must go through *
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* the queue. *
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* *
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* If the protocol being used already guarantees delivery of packets, *
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* no ACK is required for the packets. In this case, the connection *
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* class for this protocol can overload the Service routine to avoid *
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* sending ACK packets, or the Connection Manager can just mark the *
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* packet as ACK'd when it adds it to the Receive Queue for the connection.*
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* *
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* Derived classes must provide: *
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* - Init a version of Init that gives the connection *
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* access to any hardware-specific values it needs *
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* Must chain to the parent's Init routine. *
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* - Send_Packet adds the CommHeaderType header, adds the packet *
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* to the out-going queue *
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* - Receive_Packet processes incoming ACK packets, detects resends,*
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* adds new packets to the in-coming queue *
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* - Get_Packet reads the next-available packet from the *
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* receive queue *
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* - Send the hardware-dependent data-sending routine *
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* - Service_Send_Queue services the send queue; handles re-sends, *
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* detects when outgoing packets have been ACK'd; *
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* cleans out the queue of old packets *
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* - Service_Receive_Queue services the receive queue; handles sending *
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* ACK's for new or re-sent packets; cleans out *
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* the queue of old packets *
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* *
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* Any other routines can be overloaded as the derived class needs. *
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* *
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* CLASS HIERARCHY: *
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* ConnectionClass *
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* | *
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* | *
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* -------------------------------------- *
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* | | *
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* | | *
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* SequencedConnClass NonSequencedConnClass *
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* | | *
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* | | *
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* IPXConnClass ------------------------ *
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* | | | *
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* | | | *
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* IPXGlobalConnClass NullModemConnClass ModemConnClass *
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* *
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* *
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* ConnectionClass: *
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* Abstract base class. *
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* Provides: Queue for sent/recv'd packets *
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* PacketBuf for preparing packets *
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* Timeout variables *
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* Service() routine *
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* *
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* SequencedConnClass: *
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* Abstract base class *
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* Provides: * "Sequenced" ACK/Retry logic, in Service_Send_Queue() & *
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* Service_Receive_Queue() routines *
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* * Send_Packet(): adds header to packet, adds it to Queue *
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* * Receive_Packet(): adds incoming packet to receive Queue, *
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* handles incoming ACK's & resends *
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* * Get_Packet(): gets packet from the receive queue *
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* *
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* NonSequencedConnClass: *
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* Abstract base class *
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* Provides: * "Non-Sequenced" ACK/Retry logic, in Service_Send_Queue() *
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* & Service_Receive_Queue() routines *
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* * Send_Packet(): adds header to packet, adds it to Queue *
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* * Receive_Packet(): adds incoming packet to receive Queue, *
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* handles incoming ACK's & resends *
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* * Get_Packet(): gets packet from the receive queue *
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* *
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* IPXConnClass: *
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* Provides: * Hardware-dependent IPX interface routines, which allow *
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* Service_Send_Queue() & Service_Receive_Queue() to do *
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* their job *
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* * Ability to associate an IPX Address, a numerical ID, and *
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* a character-string Name with a connection *
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* Inherits: * Sequenced ACK/Retry logic, Service routines, Queue & *
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* PacketBuf, timeout variables *
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* *
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* IPXGlobalConnClass: *
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* Special type of IPX Connection; supports receiving packets from *
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* multiple systems at once, and sending packets via Broadcast or *
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* to a specific address. *
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* Provides: * Specialized Receive_Packet() routine, which handles *
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* receiving packets from multiple systems *
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* * Specialized Send_Packet() & Get_Packet() routines, *
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* which pass IPX address of destination through to *
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* the application, giving the application control over *
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* whether the packet will be Broadcast or sent to a *
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* specific destination (embeds destination address within *
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* the packet itself) *
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* * Specialized Send routine, which extracts the destination *
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* address from the packet *
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* Inherits: * Sequenced ACK/Retry logic, Service routines, Queue & *
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* PacketBuf, timeout variables, IPX-specific routines *
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* *
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* NullModemConnClass: *
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* Provides: * Hardware-dependent Serial-communication routines, which *
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* allow Service_Send_Queue() & Service_Receive_Queue() to *
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* do their job *
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* Inherits: * Non-Sequenced ACK/Retry logic, Service routines, Queue & *
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* PacketBuf, timeout variables *
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* *
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* ModemConnClass: *
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* Provides: * Hardware-dependent Modem-communication routines, which *
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* allow Service_Send_Queue() & Service_Receive_Queue() to *
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* do their job *
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* Inherits: * Non-Sequenced ACK/Retry logic, Service routines, Queue & *
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* PacketBuf, timeout variables *
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* *
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* So, do ya think this header is long enough, or what? *
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* *
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* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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#ifndef CONNECTION_H
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#define CONNECTION_H
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#define CONN_DEBUG 0
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/*
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********************************** Defines **********************************
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*/
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/*---------------------------------------------------------------------------
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This structure is the header prefixed to any packet sent by the application.
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MagicNumber: This is a number unique to the application; it's up to the
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Receive_Packet routine to check this value, to be sure we're
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not getting data from some other product. This value should
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be unique for each application.
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Code: This will be one of the below-defined codes.
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PacketID: This is a unique numerical ID for this packet. The Connection
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sets this ID on all packets sent out.
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---------------------------------------------------------------------------*/
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typedef struct {
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unsigned short MagicNumber;
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unsigned char Code;
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unsigned long PacketID;
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} CommHeaderType;
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/*
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***************************** Class Declaration *****************************
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*/
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class ConnectionClass
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{
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/*
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---------------------------- Public Interface ----------------------------
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*/
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public:
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/*.....................................................................
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These are the possible values for the Code field of the CommHeaderType:
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.....................................................................*/
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enum ConnectionEnum {
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PACKET_DATA_ACK, // this is a data packet requiring an ACK
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PACKET_DATA_NOACK, // this is a data packet not requiring an ACK
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PACKET_ACK, // this is an ACK for a packet
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PACKET_COUNT, // for computational purposes
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};
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/*.....................................................................
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Constructor/destructor.
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.....................................................................*/
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ConnectionClass (int maxlen, unsigned short magicnum,
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unsigned long retry_delta, unsigned long max_retries,
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unsigned long timeout);
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virtual ~ConnectionClass ();
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/*.....................................................................
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Initialization.
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.....................................................................*/
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virtual void Init (void) {};
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/*.....................................................................
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Send/Receive routines.
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.....................................................................*/
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virtual int Send_Packet (void * buf, int buflen, int ack_req) = 0;
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virtual int Receive_Packet (void * buf, int buflen) = 0;
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virtual int Get_Packet (void * buf, int * buflen) = 0;
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/*.....................................................................
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The main polling routine for the connection. Should be called as often
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as possible.
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.....................................................................*/
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virtual int Service (void);
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/*.....................................................................
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This routine is used by the retry logic; returns the current time in
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60ths of a second.
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.....................................................................*/
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static unsigned long Time (void);
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/*.....................................................................
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Utility routines.
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.....................................................................*/
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unsigned short Magic_Num (void) { return (MagicNum); }
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unsigned long Retry_Delta (void) { return (RetryDelta); }
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void Set_Retry_Delta (unsigned long delta) { RetryDelta = delta;}
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unsigned long Max_Retries (void) { return (MaxRetries); }
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void Set_Max_Retries (unsigned long retries) { MaxRetries = retries;}
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unsigned long Time_Out (void) { return (Timeout); }
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void Set_TimeOut (unsigned long t) { Timeout = t;}
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unsigned long Max_Packet_Len (void) { return (MaxPacketLen); }
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static char * Command_Name(int command);
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/*
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-------------------------- Protected Interface ---------------------------
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*/
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protected:
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/*.....................................................................
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Routines to service the Send & Receive queues.
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.....................................................................*/
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virtual int Service_Send_Queue(void) = 0;
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virtual int Service_Receive_Queue(void) = 0;
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/*.....................................................................
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This routine actually performs a hardware-dependent data send. It's
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pure virtual, so it >must< be defined by a derived class.
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.....................................................................*/
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virtual int Send(char *buf, int buflen) = 0;
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/*.....................................................................
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This is the maximum packet length, including our own internal header.
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.....................................................................*/
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int MaxPacketLen;
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/*.....................................................................
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Packet staging area; this is where the CommHeaderType gets tacked onto
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the application's packet before it's sent.
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.....................................................................*/
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char *PacketBuf;
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/*.....................................................................
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This is the magic number assigned to this connection. It is the first
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few bytes of any transmission.
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.....................................................................*/
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unsigned short MagicNum;
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/*.....................................................................
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This value determines the time delay before a packet is re-sent.
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.....................................................................*/
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unsigned long RetryDelta;
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/*.....................................................................
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This is the maximum number of retries allowed for a packet; if this
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value is exceeded, the connection is probably broken.
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.....................................................................*/
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unsigned long MaxRetries;
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/*.....................................................................
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This is the total timeout for this connection; if this time is exceeded
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on a packet, the connection is probably broken.
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.....................................................................*/
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unsigned long Timeout;
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/*.....................................................................
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Names of all packet commands
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.....................................................................*/
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static char *ConnectionClass::Commands[PACKET_COUNT];
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};
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#endif
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