summaryrefslogtreecommitdiffstats
path: root/src/Protocol/ProtocolRecognizer.cpp
blob: e78ed6d6ce9855f074f5ea1bd91b4abf562b1121 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423

// ProtocolRecognizer.cpp

// Implements the cProtocolRecognizer class representing the meta-protocol that recognizes possibly multiple
// protocol versions and redirects everything to them

#include "Globals.h"

#include "ProtocolRecognizer.h"
#include "Protocol_1_8.h"
#include "Protocol_1_9.h"
#include "Protocol_1_10.h"
#include "Protocol_1_11.h"
#include "Protocol_1_12.h"
#include "Protocol_1_13.h"
#include "Protocol_1_14.h"
#include "../ClientHandle.h"
#include "../Root.h"
#include "../Server.h"
#include "../World.h"
#include "../JsonUtils.h"
#include "../Bindings/PluginManager.h"





struct sUnsupportedButPingableProtocolException : public std::runtime_error
{
	explicit sUnsupportedButPingableProtocolException() :
		std::runtime_error("")
	{
	}
};





struct sTriedToJoinWithUnsupportedProtocolException : public std::runtime_error
{
	explicit sTriedToJoinWithUnsupportedProtocolException(const std::string & a_Message) :
		std::runtime_error(a_Message)
	{
	}
};





cMultiVersionProtocol::cMultiVersionProtocol() :
	HandleIncomingData(std::bind(&cMultiVersionProtocol::HandleIncomingDataInRecognitionStage, this, std::placeholders::_1, std::placeholders::_2)),
	m_Buffer(32 KiB)
{
}





AString cMultiVersionProtocol::GetVersionTextFromInt(cProtocol::Version a_ProtocolVersion)
{
	switch (a_ProtocolVersion)
	{
		case cProtocol::Version::v1_8_0:   return "1.8";
		case cProtocol::Version::v1_9_0:   return "1.9";
		case cProtocol::Version::v1_9_1:   return "1.9.1";
		case cProtocol::Version::v1_9_2:   return "1.9.2";
		case cProtocol::Version::v1_9_4:   return "1.9.4";
		case cProtocol::Version::v1_10_0:  return "1.10";
		case cProtocol::Version::v1_11_0:  return "1.11";
		case cProtocol::Version::v1_11_1:  return "1.11.1";
		case cProtocol::Version::v1_12:    return "1.12";
		case cProtocol::Version::v1_12_1:  return "1.12.1";
		case cProtocol::Version::v1_12_2:  return "1.12.2";
		case cProtocol::Version::v1_13:    return "1.13";
		case cProtocol::Version::v1_13_1:  return "1.13.1";
		case cProtocol::Version::v1_13_2:  return "1.13.2";
		case cProtocol::Version::v1_14:    return "1.14";
	}

	ASSERT(!"Unknown protocol version");
	return Printf("Unknown protocol (%d)", a_ProtocolVersion);
}





void cMultiVersionProtocol::HandleIncomingDataInRecognitionStage(cClientHandle & a_Client, std::string_view a_Data)
{
	// We read more than the handshake packet here, oh well.
	if (!m_Buffer.Write(a_Data.data(), a_Data.size()))
	{
		a_Client.Kick("Your client sent too much data; please try again later.");
		return;
	}

	try
	{
		// Note that a_Data is assigned to a subview containing the data to pass to m_Protocol or UnsupportedPing

		TryRecognizeProtocol(a_Client, a_Data);
		if (m_Protocol == nullptr)
		{
			m_Buffer.ResetRead();
			return;
		}

		// The protocol recogniser succesfully identified, switch mode:
		HandleIncomingData = [this](cClientHandle &, const std::string_view a_In)
		{
			m_Protocol->DataReceived(m_Buffer, a_In.data(), a_In.size());
		};
	}
	catch (const sUnsupportedButPingableProtocolException &)
	{
		// Got a server list ping for an unrecognised version,
		// switch into responding to unknown protocols mode:
		HandleIncomingData = [this](cClientHandle & a_Clyent, const std::string_view a_In)
		{
			HandleIncomingDataInOldPingResponseStage(a_Clyent, a_In);
		};
	}
	catch (const std::exception & Oops)
	{
		a_Client.Kick(Oops.what());
		return;
	}

	// Explicitly process any remaining data with the new handler:
	HandleIncomingData(a_Client, a_Data);
}





void cMultiVersionProtocol::HandleIncomingDataInOldPingResponseStage(cClientHandle & a_Client, const std::string_view a_Data)
{
	if (!m_Buffer.Write(a_Data.data(), a_Data.size()))
	{
		a_Client.Kick("Server list ping failed, too much data.");
		return;
	}

	cByteBuffer OutPacketBuffer(6 KiB);

	// Handle server list ping packets
	for (;;)
	{
		UInt32 PacketLen;
		UInt32 PacketID;
		if (
			!m_Buffer.ReadVarInt32(PacketLen) ||
			!m_Buffer.CanReadBytes(PacketLen) ||
			!m_Buffer.ReadVarInt32(PacketID)
		)
		{
			// Not enough data
			m_Buffer.ResetRead();
			break;
		}

		if ((PacketID == 0x00) && (PacketLen == 1))  // Request packet
		{
			HandlePacketStatusRequest(a_Client, OutPacketBuffer);
			SendPacket(a_Client, OutPacketBuffer);
		}
		else if ((PacketID == 0x01) && (PacketLen == 9))  // Ping packet
		{
			HandlePacketStatusPing(a_Client, OutPacketBuffer);
			SendPacket(a_Client, OutPacketBuffer);
		}
		else
		{
			a_Client.Kick("Server list ping failed, unrecognized packet.");
			return;
		}

		m_Buffer.CommitRead();
	}
}





void cMultiVersionProtocol::SendDisconnect(cClientHandle & a_Client, const AString & a_Reason)
{
	if (m_Protocol != nullptr)
	{
		m_Protocol->SendDisconnect(a_Reason);
		return;
	}

	const AString Message = Printf("{\"text\":\"%s\"}", EscapeString(a_Reason).c_str());
	const auto PacketID = GetPacketID(cProtocol::ePacketType::pktDisconnectDuringLogin);
	cByteBuffer Out(
		cByteBuffer::GetVarIntSize(PacketID) +
		cByteBuffer::GetVarIntSize(static_cast<UInt32>(Message.size())) + Message.size()
	);

	VERIFY(Out.WriteVarInt32(PacketID));
	VERIFY(Out.WriteVarUTF8String(Message));
	SendPacket(a_Client, Out);
}





void cMultiVersionProtocol::TryRecognizeProtocol(cClientHandle & a_Client, std::string_view & a_Data)
{
	// NOTE: If a new protocol is added or an old one is removed, adjust MCS_CLIENT_VERSIONS and MCS_PROTOCOL_VERSIONS macros in the header file

	// Lengthed protocol, try if it has the entire initial handshake packet:
	UInt32 PacketLen;
	if (!m_Buffer.ReadVarInt(PacketLen))
	{
		// Not enough bytes for the packet length, keep waiting
		return;
	}

	if (!m_Buffer.CanReadBytes(PacketLen))
	{
		// Not enough bytes for the packet, keep waiting
		// More of a sanity check to make sure no one tries anything funny (since ReadXXX can wait for data themselves):
		return;
	}

	m_Protocol = TryRecognizeLengthedProtocol(a_Client, a_Data);
	ASSERT(m_Protocol != nullptr);
}





std::unique_ptr<cProtocol> cMultiVersionProtocol::TryRecognizeLengthedProtocol(cClientHandle & a_Client, std::string_view & a_Data)
{
	UInt32 PacketType;
	UInt32 ProtocolVersion;
	AString ServerAddress;
	UInt16 ServerPort;
	UInt32 NextState;

	if (!m_Buffer.ReadVarInt(PacketType) || (PacketType != 0x00))
	{
		// Not an initial handshake packet, we don't know how to talk to them
		LOGINFO("Client \"%s\" uses an unsupported protocol (lengthed, initial packet %u)",
			a_Client.GetIPString().c_str(), PacketType
		);

		throw sTriedToJoinWithUnsupportedProtocolException(
			Printf("Your client isn't supported.\nTry connecting with Minecraft " MCS_CLIENT_VERSIONS, ProtocolVersion)
		);
	}

	if (
		!m_Buffer.ReadVarInt(ProtocolVersion) ||
		!m_Buffer.ReadVarUTF8String(ServerAddress) ||
		!m_Buffer.ReadBEUInt16(ServerPort) ||
		!m_Buffer.ReadVarInt(NextState)
	)
	{
		// TryRecognizeProtocol guarantees that we will have as much
		// data to read as the client claims in the protocol length field:
		throw sTriedToJoinWithUnsupportedProtocolException("Incorrect amount of data received - hacked client?");
	}

	// TODO: this should be a protocol property, not ClientHandle:
	a_Client.SetProtocolVersion(ProtocolVersion);

	// The protocol has just been recognized, advance data start
	// to after the handshake and leave the rest to the protocol:
	a_Data = a_Data.substr(m_Buffer.GetUsedSpace() - m_Buffer.GetReadableSpace());

	// We read more than we can handle, purge the rest:
	[[maybe_unused]] const bool Success =
		m_Buffer.SkipRead(m_Buffer.GetReadableSpace());
	ASSERT(Success);

	// All good, eat up the data:
	m_Buffer.CommitRead();

	switch (static_cast<cProtocol::Version>(ProtocolVersion))
	{
		case cProtocol::Version::v1_8_0:  return std::make_unique<cProtocol_1_8_0> (&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_9_0:  return std::make_unique<cProtocol_1_9_0> (&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_9_1:  return std::make_unique<cProtocol_1_9_1> (&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_9_2:  return std::make_unique<cProtocol_1_9_2> (&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_9_4:  return std::make_unique<cProtocol_1_9_4> (&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_10_0: return std::make_unique<cProtocol_1_10_0>(&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_11_0: return std::make_unique<cProtocol_1_11_0>(&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_11_1: return std::make_unique<cProtocol_1_11_1>(&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_12:   return std::make_unique<cProtocol_1_12>  (&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_12_1: return std::make_unique<cProtocol_1_12_1>(&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_12_2: return std::make_unique<cProtocol_1_12_2>(&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_13:   return std::make_unique<cProtocol_1_13>  (&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_13_1: return std::make_unique<cProtocol_1_13_1>(&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_13_2: return std::make_unique<cProtocol_1_13_2>(&a_Client, ServerAddress, ServerPort, NextState);
		case cProtocol::Version::v1_14:   return std::make_unique<cProtocol_1_14>  (&a_Client, ServerAddress, ServerPort, NextState);
		default:
		{
			LOGD("Client \"%s\" uses an unsupported protocol (lengthed, version %u (0x%x))",
				a_Client.GetIPString().c_str(), ProtocolVersion, ProtocolVersion
			);

			if (NextState != 1)
			{
				throw sTriedToJoinWithUnsupportedProtocolException(
					Printf("Unsupported protocol version %u.\nTry connecting with Minecraft " MCS_CLIENT_VERSIONS, ProtocolVersion)
				);
			}

			throw sUnsupportedButPingableProtocolException();
		}
	}
}





void cMultiVersionProtocol::SendPacket(cClientHandle & a_Client, cByteBuffer & a_OutPacketBuffer)
{
	// Writes out the packet normally.
	UInt32 PacketLen = static_cast<UInt32>(a_OutPacketBuffer.GetUsedSpace());
	cByteBuffer OutPacketLenBuffer(cByteBuffer::GetVarIntSize(PacketLen));

	// Compression doesn't apply to this state, send raw data:
	VERIFY(OutPacketLenBuffer.WriteVarInt32(PacketLen));
	AString LengthData;
	OutPacketLenBuffer.ReadAll(LengthData);
	a_Client.SendData(LengthData.data(), LengthData.size());

	// Send the packet's payload:
	AString PacketData;
	a_OutPacketBuffer.ReadAll(PacketData);
	a_OutPacketBuffer.CommitRead();
	a_Client.SendData(PacketData.data(), PacketData.size());
}





UInt32 cMultiVersionProtocol::GetPacketID(cProtocol::ePacketType a_PacketType)
{
	switch (a_PacketType)
	{
		case cProtocol::ePacketType::pktDisconnectDuringLogin: return 0x00;
		case cProtocol::ePacketType::pktStatusResponse:        return 0x00;
		case cProtocol::ePacketType::pktPingResponse:          return 0x01;
		default:
		{
			ASSERT(!"GetPacketID() called for an unhandled packet");
			return 0;
		}
	}
}





void cMultiVersionProtocol::HandlePacketStatusRequest(cClientHandle & a_Client, cByteBuffer & a_Out)
{
	cServer * Server = cRoot::Get()->GetServer();
	AString ServerDescription = Server->GetDescription();
	auto NumPlayers = static_cast<signed>(Server->GetNumPlayers());
	auto MaxPlayers = static_cast<signed>(Server->GetMaxPlayers());
	AString Favicon = Server->GetFaviconData();
	cRoot::Get()->GetPluginManager()->CallHookServerPing(a_Client, ServerDescription, NumPlayers, MaxPlayers, Favicon);

	// Version:
	Json::Value Version;
	Version["name"] = "Cuberite " MCS_CLIENT_VERSIONS;
	Version["protocol"] = MCS_LATEST_PROTOCOL_VERSION;

	// Players:
	Json::Value Players;
	Players["online"] = NumPlayers;
	Players["max"] = MaxPlayers;
	// TODO: Add "sample"

	// Description:
	Json::Value Description;
	Description["text"] = ServerDescription.c_str();

	// Create the response:
	Json::Value ResponseValue;
	ResponseValue["version"] = Version;
	ResponseValue["players"] = Players;
	ResponseValue["description"] = Description;
	if (!Favicon.empty())
	{
		ResponseValue["favicon"] = Printf("data:image/png;base64,%s", Favicon.c_str());
	}

	AString Response = JsonUtils::WriteFastString(ResponseValue);

	VERIFY(a_Out.WriteVarInt32(GetPacketID(cProtocol::ePacketType::pktStatusResponse)));
	VERIFY(a_Out.WriteVarUTF8String(Response));
}





void cMultiVersionProtocol::HandlePacketStatusPing(cClientHandle & a_Client, cByteBuffer & a_Out)
{
	Int64 Timestamp;
	if (!m_Buffer.ReadBEInt64(Timestamp))
	{
		return;
	}

	VERIFY(a_Out.WriteVarInt32(GetPacketID(cProtocol::ePacketType::pktPingResponse)));
	VERIFY(a_Out.WriteBEInt64(Timestamp));
}