sources/network/rconsession.cpp

/*
	Copyright 2014 - 2016 Teemu Piippo
	All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions
	are met:

	1. Redistributions of source code must retain the above copyright
	   notice, this list of conditions and the following disclaimer.
	2. Redistributions in binary form must reproduce the above copyright
	   notice, this list of conditions and the following disclaimer in the
	   documentation and/or other materials provided with the distribution.
	3. Neither the name of the copyright holder nor the names of its
	   contributors may be used to endorse or promote products derived from
	   this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER
	OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <time.h>
#include "rconsession.h"
#include "../interface.h"
BEGIN_ZFC_NAMESPACE

struct PacketHeader
{
	int32_t header;
	int sequenceNumber;
};

// -------------------------------------------------------------------------------------------------
//
RCONSession::RCONSession() :
	m_state(RCON_DISCONNECTED),
	m_lastPing(0),
	m_adminCount(0),
    m_lastMissingPacketRequest(0),
	m_interface(nullptr)
{
	if (not m_socket.set_blocking(false))
	{
		fprintf(stderr, "unable to set socket as non-blocking: %s\n",
			m_socket.error_string().chars());
		exit(EXIT_FAILURE);
	}
}

// -------------------------------------------------------------------------------------------------
//
RCONSession::~RCONSession() {}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::connect(IPAddress address)
{
	m_address = address;
	m_state = RCON_CONNECTING;
	m_interface->updateStatusBar();
	sendHello();
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::disconnect()
{
	if (m_state > RCON_CONNECTING)
	{
		// Say goodbye to remote
		send({CLRC_DISCONNECT});
		m_interface->disconnected();
	}

	m_state = RCON_DISCONNECTED;
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::send(const ByteArray& packet)
{
	m_socket.send(m_address, packet);
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::tick()
{
	if (m_state == RCON_DISCONNECTED)
		return;

	time_t now;
	time(&now);

	if (m_lastPing < now)
	{
		if (m_state == RCON_CONNECTING)
		{
			sendHello();
		}
		else if (m_state == RCON_AUTHENTICATING)
		{
			sendPassword();
		}
		else if (m_state == RCON_CONNECTED and m_lastPing + 5 < now)
		{
			send({CLRC_PONG});
			bumpLastPing();
		}
	}

	// Check for new packets in our socket
	for (Datagram datagram; m_socket.read(datagram);)
	{
		// Only process packets that originate from the game server.
		if (datagram.address == m_address)
		{
			// Parse and cut off the header.
			PacketHeader header;
			{
				// Read the header, and find the sequence number
				Bytestream stream(datagram.message);
				header.header = stream.readLong();
				header.sequenceNumber = (header.header != 0) ? stream.readLong() : -1;
				datagram.message = datagram.message.splice(stream.position(), datagram.message.size());
			}

			// Try to store this packet into the queue. However, do not try to store packets without a sequence number.
			bool stored = false;

			if (header.sequenceNumber != -1)
				stored = m_packetQueue.addPacket(header.sequenceNumber, datagram.message);

			// If the packet was not stored, we are to just process it right away.
			if (stored == false)
				handlePacket(datagram.message);
		}
	}

	// Check if we can now also process some packets from the queue.
	if (m_packetQueue.hasPacketsToPop())
	{
		ByteArray message;
		while (m_packetQueue.popNextPacket(message))
			handlePacket(message);
	}

	// Check whether there are packets stuck in the queue. If this is the case, we have lost some packets and need to
	// ask the game server to re-send them.
	if (m_packetQueue.isStuck()  and  m_lastMissingPacketRequest + 1 < time(NULL))
	{
		m_interface->printWarning("Missing packets detected. Packets currently in queue:\n");

		for (int packetNumber : m_packetQueue.getWaitingPackets())
			m_interface->printWarning("- %d:\n", packetNumber);

		m_lastMissingPacketRequest = time(NULL);
		ByteArray message;
		Bytestream stream(message);
		stream.writeByte(CLRC_MISSINGPACKET);

		for (int packetNumber : m_packetQueue.getLostPackets())
		{
			m_interface->printWarning("Requesting lost packet %d\n", packetNumber);
			stream.writeLong(packetNumber);
		}

		send(message);
	}
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::handlePacket(ByteArray& message)
{
	Bytestream stream(message);

	try
	{
		while (stream.bytesLeft() > 0)
		{
			int header = stream.readByte();

			switch (ServerResponse(header))
			{
			case SVRC_OLDPROTOCOL:
				m_interface->printError("Your RCON client is using outdated protocol.\n");
				m_state = RCON_DISCONNECTED;
				break;

			case SVRC_BANNED:
				m_interface->printError("You have been banned from the server.\n");
				m_state = RCON_DISCONNECTED;
				break;

			case SVRC_SALT:
				m_salt = stream.readString();
				m_state = RCON_AUTHENTICATING;
				sendPassword();
				break;

			case SVRC_INVALIDPASSWORD:
				m_interface->printError("Login failed.\n");
				m_state = RCON_DISCONNECTED;
				break;

			case SVRC_MESSAGE:
				{
					String message = stream.readString();
					message.normalize();
					m_interface->printText("%s\n", message.chars());
				}
				break;

			case SVRC_LOGGEDIN:
				m_interface->print("Login successful!\n");
				m_serverProtocol = stream.readByte();
				m_hostname = stream.readString();
				m_interface->setTitle(m_hostname);
				m_state = RCON_CONNECTED;

				for (int i = stream.readByte(); i > 0; --i)
					processServerUpdates(stream);

				m_interface->print("Previous messages:\n");

				for (int i = stream.readByte(); i > 0; --i)
				{
					String message = stream.readString();
					message.normalize();
					m_interface->printText("--- %s\n", message.chars());
				}

				m_interface->print("End of previous messages.\n");

				// Watch sv_hostname so that we can update the titlebar when it changes.
				requestWatch("sv_hostname");
				m_interface->print ("Watch requested.\n");
				break;

			case SVRC_UPDATE:
				processServerUpdates(stream);
				break;

			case SVRC_TOOMANYTABCOMPLETES:
				{
					unsigned int numCompletions = stream.readShort();
					m_interface->print("%d completions for '%s'.\n",
						int(numCompletions), m_lastTabComplete.chars());
				}
				break;

			case SVRC_TABCOMPLETE:
				{
					StringList completes;
					completes.resize(stream.readByte());

					for (String& completion : completes)
						completion = stream.readString();

					if (completes.size() == 1)
					{
						m_interface->tabComplete(m_lastTabComplete, completes[0]);
					}
					else if (not completes.is_empty())
					{
						m_interface->print("Completions for '%s':\n", m_lastTabComplete.chars());

						for (int i : range(0, completes.size(), 8))
						{
							Range<int> spliceRange(i, min(i + 8, completes.size()));
							StringList splice(completes.splice(spliceRange));
							m_interface->print("- %s\n", splice.join(", ").chars());
						}
					}
				}
				break;

			case SVRC_WATCHINGCVAR:
				m_interface->print ("You are now watching %s\n", stream.readString().chars());
				m_interface->print ("Its value is: %s\n", stream.readString().chars());
				break;

			case SVRC_ALREADYWATCHINGCVAR:
				m_interface->print ("You are already watching %s\n", stream.readString().chars());
				break;

			case SVRC_WATCHCVARNOTFOUND:
				m_interface->print ("CVar %s not found\n", stream.readString().chars());
				break;

			case SVRC_CVARCHANGED:
				{
					String name = stream.readString();
					String value = stream.readString();
					m_interface->print ("The value of CVar %s", name.chars());
					m_interface->print (" is now %s\n", value.chars());

					// If sv_hostname changes, update the titlebar
					if (name == "sv_hostname")
					{
						m_hostname = value;
						m_interface->setTitle(m_hostname);
					}
				}
				break;

			case SVRC_YOUREDISCONNECTED:
				m_interface->print ("You have been disconnected: %s\n", stream.readString().chars());
				m_interface->disconnected();
				break;
			}
		}
	}
	catch (std::exception& e)
	{
		m_interface->printWarning("Couldn't process packet: %s\n", e.what());
		m_interface->printWarning("Packet contents was: %s\n", message.quote().chars());
		m_interface->printWarning("Stream position in payload was: %d\n", stream.position());
	}
}

void RCONSession::processServerUpdates(Bytestream& packet)
{
	int header = packet.readByte();

	switch (RCONUpdateType(header))
	{
	case SVRCU_PLAYERDATA:
		{
			StringList players;

			for (int i = packet.readByte(); i > 0; --i)
				players.append(packet.readString());

			m_interface->setPlayerNames(players);
		}
		break;

	case SVRCU_ADMINCOUNT:
		m_adminCount = packet.readByte();
		m_interface->updateStatusBar();
		break;

	case SVRCU_MAP:
		m_level = packet.readString();
		m_interface->updateStatusBar();
		break;

	default:
		m_interface->printWarning("Unknown server update type: %d\n", header);
		break;
	}
}

// -------------------------------------------------------------------------------------------------
//
UDPSocket* RCONSession::getSocket()
{
	return &m_socket;
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::sendHello()
{
	m_interface->print("Connecting to %s...\n", m_address.to_string(IPAddress::WITH_PORT).chars());
	send({CLRC_BEGINCONNECTION, RCON_PROTOCOL_VERSION});
	bumpLastPing();
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::sendPassword()
{
	m_interface->print("Authenticating...\n");
	ByteArray message;
	Bytestream stream(message);
	stream.writeByte(CLRC_PASSWORD);
	stream.writeString((m_salt + m_password).md5());
	send(message);
	bumpLastPing();
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::setPassword(const String& password)
{
	m_password = password;
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::bumpLastPing()
{
	time_t now;
	time(&now);
	m_lastPing = now;
}

// -------------------------------------------------------------------------------------------------
//
bool RCONSession::isActive() const
{
	return getState() != RCON_DISCONNECTED;
}

// -------------------------------------------------------------------------------------------------
// Returns true if the message was successfully sent.
//
bool RCONSession::sendCommand(const String& commandString)
{
	if (m_state != RCON_CONNECTED or commandString.isEmpty())
		return false;

	ByteArray message;
	Bytestream stream(message);
	stream.writeByte(CLRC_COMMAND);
	stream.writeString(commandString);
	send(message);
	bumpLastPing();
	return true;
}

// -------------------------------------------------------------------------------------------------
//
RCONSessionState RCONSession::getState() const
{
	return m_state;
}

// -------------------------------------------------------------------------------------------------
//
const IPAddress& RCONSession::address() const
{
	return m_address;
}

// -------------------------------------------------------------------------------------------------
//
int RCONSession::getAdminCount() const
{
	return m_adminCount;
}

// -------------------------------------------------------------------------------------------------
//
const String& RCONSession::getLevel() const
{
	return m_level;
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::requestTabCompletion(const String& part)
{
	if (m_serverProtocol >= 4)
	{
		ByteArray message;
		Bytestream stream(message);
		stream.writeByte(CLRC_TABCOMPLETE);
		stream.writeString(part);
		send(message);
		bumpLastPing();
		m_lastTabComplete = part;
	}
	else
	{
		m_interface->print("This server does not support tab-completion\n", m_serverProtocol);
	}
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::setInterface(Interface* interface)
{
	m_interface = interface;
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::requestWatch(const String& cvar)
{
	StringList cvars;
	cvars.append(cvar);
	requestWatch(cvars);
}

// -------------------------------------------------------------------------------------------------
//
void RCONSession::requestWatch(const StringList& cvars)
{
	ByteArray message;
	Bytestream stream(message);
	stream.writeByte(CLRC_WATCHCVAR);

	for (const String& cvar : cvars)
		stream.writeString(cvar.normalized());

	stream.writeString("");
	send(message);
}

END_ZFC_NAMESPACE