/* Copyright (C) 2024 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see .
*/
#ifndef NETSESSION_H
#define NETSESSION_H
#include "lib/external_libraries/enet.h"
#include "network/FSM.h"
#include "network/NetFileTransfer.h"
#include "network/NetHost.h"
#include "ps/CStr.h"
#include
#include
/**
* Report the peer if we didn't receive a packet after this time (milliseconds).
*/
inline constexpr u32 NETWORK_WARNING_TIMEOUT = 2000;
class CNetClient;
class CNetServerWorker;
class CNetStatsTable;
typedef struct _ENetHost ENetHost;
/**
* @file
* Network client/server sessions.
*
* Each session has two classes: CNetClientSession runs on the client,
* and CNetServerSession runs on the server.
* A client runs one session at once; a server typically runs many.
*/
/**
* Interface for sessions to which messages can be sent.
*/
class INetSession
{
public:
virtual ~INetSession() {}
virtual bool SendMessage(const CNetMessage* message) = 0;
};
/**
* The client end of a network session.
* Provides an abstraction of the network interface, allowing communication with the server.
* The NetClientSession is threaded, so all calls to the public interface must be thread-safe.
*/
class CNetClientSession : public INetSession
{
NONCOPYABLE(CNetClientSession);
public:
CNetClientSession(CNetClient& client);
~CNetClientSession();
bool Connect(const CStr& server, const u16 port, ENetHost* enetClient);
/**
* The client NetSession is threaded to avoid getting timeouts if the main thread hangs.
* Call Connect() before starting this loop.
*/
static void RunNetLoop(CNetClientSession* session);
/**
* Shut down the net session.
*/
void Shutdown();
/**
* Processes pending messages.
*/
void ProcessPolledMessages();
/**
* Queue up a message to send to the server on the next Loop() call.
*/
virtual bool SendMessage(const CNetMessage* message) override;
/**
* Number of milliseconds since the most recent packet of the server was received.
*/
u32 GetLastReceivedTime() const;
/**
* Average round trip time to the server.
*/
u32 GetMeanRTT() const;
CNetFileTransferer& GetFileTransferer() { return m_FileTransferer; }
private:
/**
* Process queued incoming messages.
*/
void Poll();
/**
* Flush queued outgoing network messages.
*/
void Flush();
CNetClient& m_Client;
CNetFileTransferer m_FileTransferer;
// Net messages received and waiting for fetching.
boost::lockfree::queue m_IncomingMessages;
// Net messages to send on the next flush() call.
boost::lockfree::queue m_OutgoingMessages;
// Last know state. If false, flushing errors are silenced.
bool m_Connected = false;
// Wrapper around enet stats - those are atomic as the code is lock-free.
std::atomic m_LastReceivedTime;
std::atomic m_MeanRTT;
// If this is true, calling Connect() or deleting the session is an error.
std::atomic m_LoopRunning;
std::atomic m_ShouldShutdown;
ENetHost* m_Host;
ENetPeer* m_Server;
CNetStatsTable* m_Stats;
};
/**
* The server's end of a network session.
* Represents an abstraction of the state of the client, storing all the per-client data
* needed by the server.
*
* Thread-safety:
* - This is constructed and used by CNetServerWorker in the network server thread.
*/
class CNetServerSession : public CFsm, public INetSession
{
NONCOPYABLE(CNetServerSession);
public:
CNetServerSession(CNetServerWorker& server, ENetPeer* peer);
CNetServerWorker& GetServer() { return m_Server; }
const CStr& GetGUID() const { return m_GUID; }
void SetGUID(const CStr& guid) { m_GUID = guid; }
const CStrW& GetUserName() const { return m_UserName; }
void SetUserName(const CStrW& name) { m_UserName = name; }
u32 GetHostID() const { return m_HostID; }
void SetHostID(u32 id) { m_HostID = id; }
u32 GetIPAddress() const;
/**
* Number of milliseconds since the latest packet of that client was received.
*/
u32 GetLastReceivedTime() const;
/**
* Average round trip time to the client.
*/
u32 GetMeanRTT() const;
/**
* Sends a disconnection notification to the client,
* and sends a NMT_CONNECTION_LOST message to the session FSM.
* The server will receive a disconnection notification after a while.
* The server will not receive any further messages sent via this session.
*/
void Disconnect(NetDisconnectReason reason);
/**
* Sends an unreliable disconnection notification to the client.
* The server will not receive any disconnection notification.
* The server will not receive any further messages sent via this session.
*/
void DisconnectNow(NetDisconnectReason reason);
/**
* Send a message to the client.
*/
virtual bool SendMessage(const CNetMessage* message);
CNetFileTransferer& GetFileTransferer() { return m_FileTransferer; }
private:
CNetServerWorker& m_Server;
CNetFileTransferer m_FileTransferer;
ENetPeer* m_Peer;
CStr m_GUID;
CStrW m_UserName;
u32 m_HostID;
CStr m_Password;
};
#endif // NETSESSION_H