Compare timebase of netplay users to detect desyncs.

Source/Core/Core/ConfigManager.h

@@ -118,6 +118,8 @@ struct SConfig : NonCopyable
 	bool m_GameCubeAdapter;
 	bool m_AdapterRumble;
 
+	bool m_NetplayDesyncCheck;
+
 	SysConf* m_SYSCONF;
 
 	// Save settings

Source/Core/Core/Movie.cpp

@@ -17,6 +17,7 @@
 #include "Core/Core.h"
 #include "Core/CoreTiming.h"
 #include "Core/Movie.h"
+#include "Core/NetPlayClient.h"
 #include "Core/NetPlayProto.h"
 #include "Core/State.h"
 #include "Core/DSP/DSPCore.h"
@@ -163,6 +164,9 @@ void FrameUpdate()
 		FrameSkipping();
 
 	s_bPolled = false;
+
+	if (NetPlay::IsNetPlayRunning() && SConfig::GetInstance().m_NetplayDesyncCheck)
+		NetPlayClient::SendTimeBase();
 }
 
 // called when game is booting up, even if no movie is active,

Source/Core/Core/NetPlayClient.cpp

@@ -374,6 +374,7 @@ unsigned int NetPlayClient::OnData(sf::Packet& packet)
 	case NP_MSG_START_GAME:
 	{
 		{
+			SConfig::GetInstance().m_NetplayDesyncCheck = true;
 			std::lock_guard<std::recursive_mutex> lkg(m_crit.game);
 			packet >> m_current_game;
 			packet >> g_NetPlaySettings.m_CPUthread;
@@ -442,6 +443,24 @@ unsigned int NetPlayClient::OnData(sf::Packet& packet)
 	}
 	break;
 
+	case NP_MSG_DESYNC_DETECTED:
+	{
+		if (!SConfig::GetInstance().m_NetplayDesyncCheck)
+			break;
+
+		int id;
+		u32 frame;
+		packet >> id;
+		packet >> frame;
+		std::string sID = "";
+		if (id != -1)
+			sID = StringFromFormat(" from player ID %d", id);
+
+		m_dialog->AppendChat("Possible desync detected" + sID + StringFromFormat(" on frame: %u", frame));
+		SConfig::GetInstance().m_NetplayDesyncCheck = false;
+	}
+	break;
+
 	default:
 		PanicAlertT("Unknown message received with id : %d", mid);
 		break;
@@ -1044,6 +1063,20 @@ u8 NetPlayClient::LocalWiimoteToInGameWiimote(u8 local_pad)
 	return ingame_pad;
 }
 
+void NetPlayClient::SendTimeBase()
+{
+	std::lock_guard<std::mutex> lk(crit_netplay_client);
+
+	u64 timebase = SystemTimers::GetFakeTimeBase();
+
+	sf::Packet* spac = new sf::Packet;
+	*spac << (MessageId)NP_MSG_TIMEBASE;
+	*spac << (u32)timebase;
+	*spac << (u32)(timebase << 32);
+	*spac << (u32)Movie::g_currentFrame;
+	netplay_client->SendAsync(spac);
+}
+
 // stuff hacked into dolphin
 
 // called from ---CPU--- thread

Source/Core/Core/NetPlayClient.h

@@ -77,6 +77,8 @@ public:
 
 	u8 LocalWiimoteToInGameWiimote(u8 local_pad);
 
+	static void SendTimeBase();
+
 	enum State
 	{
 		WaitingForTraversalClientConnection,

Source/Core/Core/NetPlayProto.h

@@ -29,7 +29,7 @@ struct Rpt : public std::vector<u8>
 
 typedef std::vector<u8> NetWiimote;
 
-#define NETPLAY_VERSION  "Dolphin NetPlay 2014-01-08"
+#define NETPLAY_VERSION  "Dolphin NetPlay 2015-03-10"
 
 extern u64 g_netplay_initial_gctime;
 
@@ -53,6 +53,9 @@ enum
 	NP_MSG_STOP_GAME = 0xA2,
 	NP_MSG_DISABLE_GAME = 0xA3,
 
+	NP_MSG_TIMEBASE = 0xB0,
+	NP_MSG_DESYNC_DETECTED = 0xB1,
+
 	NP_MSG_READY = 0xD0,
 	NP_MSG_NOT_READY = 0xD1,
 

Source/Core/Core/NetPlayServer.cpp

@@ -23,6 +23,8 @@
 
 u64 g_netplay_initial_gctime = 1272737767;
 
+static std::map<u32, std::vector<std::pair<u64, u8>>> s_timebase;
+
 NetPlayServer::~NetPlayServer()
 {
 	if (is_connected)
@@ -110,8 +112,7 @@ void NetPlayServer::ThreadFunc()
 	while (m_do_loop)
 	{
 		// update pings every so many seconds
-
-		if ((m_ping_timer.GetTimeElapsed() > 1000) || m_update_pings)
+		if (m_update_pings || (m_ping_timer.GetTimeElapsed() > 1000))
 		{
 			m_ping_key = Common::Timer::GetTimeMs();
 
@@ -208,6 +209,7 @@ void NetPlayServer::ThreadFunc()
 			break;
 			}
 		}
+		Common::SleepCurrentThread(1);
 	}
 
 	// close listening socket and client sockets
@@ -581,6 +583,50 @@ unsigned int NetPlayServer::OnData(sf::Packet& packet, Client& player)
 	}
 	break;
 
+	case NP_MSG_TIMEBASE:
+	{
+		u32 x, y, frame;
+		packet >> x;
+		packet >> y;
+		packet >> frame;
+		s_timebase[frame].emplace_back(x | ((u64)y >> 32), player.pid);
+
+		if (!std::all_of(s_timebase[frame].begin(), s_timebase[frame].end(), [&frame](std::pair<u64, u8> i){ return i.first == s_timebase[frame][0].first; }))
+		{
+			sf::Packet spac;
+			spac << (MessageId) NP_MSG_DESYNC_DETECTED;
+
+			int pid = -1;
+			if (s_timebase[frame].size() > 2)
+			{
+				for (auto time : s_timebase[frame])
+				{
+					int count = 0;
+					for (auto _time : s_timebase[frame])
+					{
+						if (_time.first == time.first)
+							count++;
+					}
+					if ((size_t)count != s_timebase[frame].size() - 1)
+					{
+						if (pid == -1)
+						{
+							pid = time.second;
+						}
+						else
+						{
+							pid = -1;
+							break;
+						}
+					}
+				}
+			}
+			spac << pid;
+			spac << frame;
+			SendToClients(spac);
+		}
+	}
+	break;
 	default:
 		PanicAlertT("Unknown message with id:%d received from player:%d Kicking player!", mid, player.pid);
 		// unknown message, kick the client
@@ -635,6 +681,7 @@ void NetPlayServer::SetNetSettings(const NetSettings &settings)
 // called from ---GUI--- thread
 bool NetPlayServer::StartGame()
 {
+	s_timebase.clear();
 	std::lock_guard<std::recursive_mutex> lkg(m_crit.game);
 	m_current_game = Common::Timer::GetTimeMs();