Merge #3942

3942: Allow the antibot to get more insight into the network r=Learath2 a=heinrich5991

E.g. allow it to see the messages the server sends.

<!-- What is the motivation for the changes of this pull request -->

## Checklist

- [x] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test if it works standalone, system.c especially
- [x] Considered possible null pointers and out of bounds array indexing
- [ ] Changed no physics that affect existing maps
- [ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)


Co-authored-by: heinrich5991 <heinrich5991@gmail.com>

src/antibot/antibot_data.h

@@ -6,7 +6,7 @@
 
 enum
 {
-	ANTIBOT_ABI_VERSION = 3,
+	ANTIBOT_ABI_VERSION = 4,
 
 	ANTIBOT_MSGFLAG_NONVITAL = 1,
 	ANTIBOT_MSGFLAG_FLUSH = 2,

src/antibot/antibot_interface.h

@@ -29,7 +29,11 @@ ANTIBOTAPI void AntibotOnHookAttach(int ClientID, bool Player);
 ANTIBOTAPI void AntibotOnEngineTick(void);
 ANTIBOTAPI void AntibotOnEngineClientJoin(int ClientID, bool Sixup);
 ANTIBOTAPI void AntibotOnEngineClientDrop(int ClientID, const char *pReason);
-ANTIBOTAPI void AntibotOnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags);
+// Returns true if the message shouldn't be processed by the server.
+ANTIBOTAPI bool AntibotOnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags);
+ANTIBOTAPI bool AntibotOnEngineServerMessage(int ClientID, const void *pData, int Size, int Flags);
+// Returns true if the server should simulate receiving a client message.
+ANTIBOTAPI bool AntibotOnEngineSimulateClientMessage(int *pClientID, void *pBuffer, int BufferSize, int *pOutSize, int *pFlags);
 }
 
 #endif // ANTIBOT_ANTIBOT_INTERFACE_H

src/antibot/antibot_null.cpp

@@ -35,5 +35,7 @@ void AntibotOnHookAttach(int /*ClientID*/, bool /*Player*/) {}
 void AntibotOnEngineTick(void) {}
 void AntibotOnEngineClientJoin(int /*ClientID*/, bool /*Sixup*/) {}
 void AntibotOnEngineClientDrop(int /*ClientID*/, const char * /*pReason*/) {}
-void AntibotOnEngineClientMessage(int /*ClientID*/, const void * /*pData*/, int /*Size*/, int /*Flags*/) {}
+bool AntibotOnEngineClientMessage(int /*ClientID*/, const void * /*pData*/, int /*Size*/, int /*Flags*/) { return false; }
+bool AntibotOnEngineServerMessage(int /*ClientID*/, const void * /*pData*/, int /*Size*/, int /*Flags*/) { return false; }
+bool AntibotOnEngineSimulateClientMessage(int * /*pClientID*/, void * /*pBuffer*/, int /*BufferSize*/, int * /*pOutSize*/, int * /*pFlags*/) { return false; }
 }

src/engine/antibot.h

@@ -37,7 +37,9 @@ public:
 	virtual void OnEngineTick() = 0;
 	virtual void OnEngineClientJoin(int ClientID, bool Sixup) = 0;
 	virtual void OnEngineClientDrop(int ClientID, const char *pReason) = 0;
-	virtual void OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags) = 0;
+	virtual bool OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags) = 0;
+	virtual bool OnEngineServerMessage(int ClientID, const void *pData, int Size, int Flags) = 0;
+	virtual bool OnEngineSimulateClientMessage(int *pClientID, void *pBuffer, int BufferSize, int *pOutSize, int *pFlags) = 0;
 
 	virtual ~IEngineAntibot(){};
 };

src/engine/server/antibot.cpp

@@ -156,7 +156,7 @@ void CAntibot::OnEngineClientDrop(int ClientID, const char *pReason)
 	Update();
 	AntibotOnEngineClientDrop(ClientID, pReason);
 }
-void CAntibot::OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags)
+bool CAntibot::OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags)
 {
 	Update();
 	int AntibotFlags = 0;
@@ -164,7 +164,31 @@ void CAntibot::OnEngineClientMessage(int ClientID, const void *pData, int Size,
 	{
 		AntibotFlags |= ANTIBOT_MSGFLAG_NONVITAL;
 	}
-	AntibotOnEngineClientMessage(ClientID, pData, Size, Flags);
+	return AntibotOnEngineClientMessage(ClientID, pData, Size, Flags);
+}
+bool CAntibot::OnEngineServerMessage(int ClientID, const void *pData, int Size, int Flags)
+{
+	Update();
+	int AntibotFlags = 0;
+	if((Flags & MSGFLAG_VITAL) == 0)
+	{
+		AntibotFlags |= ANTIBOT_MSGFLAG_NONVITAL;
+	}
+	return AntibotOnEngineServerMessage(ClientID, pData, Size, Flags);
+}
+bool CAntibot::OnEngineSimulateClientMessage(int *pClientID, void *pBuffer, int BufferSize, int *pOutSize, int *pFlags)
+{
+	int AntibotFlags = 0;
+	bool Result = AntibotOnEngineSimulateClientMessage(pClientID, pBuffer, BufferSize, pOutSize, &AntibotFlags);
+	if(Result)
+	{
+		*pFlags = 0;
+		if((AntibotFlags & ANTIBOT_MSGFLAG_NONVITAL) == 0)
+		{
+			*pFlags |= MSGFLAG_VITAL;
+		}
+	}
+	return Result;
 }
 #else
 CAntibot::CAntibot() :
@@ -209,7 +233,9 @@ void CAntibot::OnHookAttach(int ClientID, bool Player) {}
 void CAntibot::OnEngineTick() {}
 void CAntibot::OnEngineClientJoin(int ClientID, bool Sixup) {}
 void CAntibot::OnEngineClientDrop(int ClientID, const char *pReason) {}
-void CAntibot::OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags) {}
+bool CAntibot::OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags) { return false; }
+bool CAntibot::OnEngineServerMessage(int ClientID, const void *pData, int Size, int Flags) { return false; }
+bool CAntibot::OnEngineSimulateClientMessage(int *pClientID, void *pBuffer, int BufferSize, int *pOutSize, int *pFlags) { return false; }
 #endif
 
 IEngineAntibot *CreateEngineAntibot()

src/engine/server/antibot.h

@@ -33,7 +33,9 @@ public:
 	virtual void OnEngineTick();
 	virtual void OnEngineClientJoin(int ClientID, bool Sixup);
 	virtual void OnEngineClientDrop(int ClientID, const char *pReason);
-	virtual void OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags);
+	virtual bool OnEngineClientMessage(int ClientID, const void *pData, int Size, int Flags);
+	virtual bool OnEngineServerMessage(int ClientID, const void *pData, int Size, int Flags);
+	virtual bool OnEngineSimulateClientMessage(int *pClientID, void *pBuffer, int BufferSize, int *pOutSize, int *pFlags);
 
 	// Game
 	virtual void RoundStart(class IGameServer *pGameServer);

src/engine/server/server.cpp

@@ -778,6 +778,10 @@ int CServer::SendMsg(CMsgPacker *pMsg, int Flags, int ClientID)
 					Packet.m_pData = pPack->Data();
 					Packet.m_DataSize = pPack->Size();
 					Packet.m_ClientID = i;
+					if(Antibot()->OnEngineServerMessage(i, Packet.m_pData, Packet.m_DataSize, Flags))
+					{
+						continue;
+					}
 					m_NetServer.Send(&Packet);
 				}
 			}
@@ -793,6 +797,11 @@ int CServer::SendMsg(CMsgPacker *pMsg, int Flags, int ClientID)
 		Packet.m_pData = Pack.Data();
 		Packet.m_DataSize = Pack.Size();
 
+		if(Antibot()->OnEngineServerMessage(ClientID, Packet.m_pData, Packet.m_DataSize, Flags))
+		{
+			return 0;
+		}
+
 		if(!(Flags & MSGFLAG_NORECORD))
 		{
 			m_aDemoRecorder[ClientID].RecordMessage(Pack.Data(), Pack.Size());
@@ -1319,13 +1328,6 @@ void CServer::ProcessClientPacket(CNetChunk *pPacket)
 	Unpacker.Reset(pPacket->m_pData, pPacket->m_DataSize);
 	CMsgPacker Packer(NETMSG_EX, true);
 
-	int GameFlags = 0;
-	if(pPacket->m_Flags & NET_CHUNKFLAG_VITAL)
-	{
-		GameFlags |= MSGFLAG_VITAL;
-	}
-	Antibot()->OnEngineClientMessage(ClientID, pPacket->m_pData, pPacket->m_DataSize, GameFlags);
-
 	// unpack msgid and system flag
 	int Msg;
 	bool Sys;
@@ -2244,10 +2246,36 @@ void CServer::PumpNetwork(bool PacketWaiting)
 			}
 			else
 			{
+				int GameFlags = 0;
+				if(Packet.m_Flags & NET_CHUNKFLAG_VITAL)
+				{
+					GameFlags |= MSGFLAG_VITAL;
+				}
+				if(Antibot()->OnEngineClientMessage(Packet.m_ClientID, Packet.m_pData, Packet.m_DataSize, GameFlags))
+				{
+					continue;
+				}
+
 				ProcessClientPacket(&Packet);
 			}
 		}
 	}
+	{
+		unsigned char aBuffer[NET_MAX_PAYLOAD];
+		int Flags;
+		CNetChunk Packet;
+		mem_zero(&Packet, sizeof(Packet));
+		Packet.m_pData = aBuffer;
+		while(Antibot()->OnEngineSimulateClientMessage(&Packet.m_ClientID, aBuffer, sizeof(aBuffer), &Packet.m_DataSize, &Flags))
+		{
+			Packet.m_Flags = 0;
+			if(Flags & MSGFLAG_VITAL)
+			{
+				Packet.m_Flags |= NET_CHUNKFLAG_VITAL;
+			}
+			ProcessClientPacket(&Packet);
+		}
+	}
 
 	m_ServerBan.Update();
 	m_Econ.Update();