2 files changed, 84 insertions, 6 deletions

diff --git a/Minecraft.Client/Common/Network/GameNetworkManager.cpp b/Minecraft.Client/Common/Network/GameNetworkManager.cpp
index 92ea8ad0..88db4911 100644
--- a/Minecraft.Client/Common/Network/GameNetworkManager.cpp
+++ b/Minecraft.Client/Common/Network/GameNetworkManager.cpp
@@ -41,6 +41,11 @@
 #include "..\Minecraft.World\DurangoStats.h"
 #endif
 
+#ifdef _WINDOWS64
+#include "..\..\Windows64\Network\WinsockNetLayer.h"
+#include "..\..\Windows64\Windows64_Xuid.h"
+#endif
+
 // Global instance
 CGameNetworkManager g_NetworkManager;
 CPlatformNetworkManager *CGameNetworkManager::s_pPlatformNetworkManager;
@@ -1501,6 +1506,45 @@ void CGameNetworkManager::CreateSocket( INetworkPlayer *pNetworkPlayer, bool loc
 	}
 	else
 	{
+#ifdef _WINDOWS64
+		// Non-host split-screen: open a dedicated TCP connection for this pad
+		if (localPlayer && !g_NetworkManager.IsHost() && g_NetworkManager.IsInGameplay())
+		{
+			int padIdx = pNetworkPlayer->GetUserIndex();
+			BYTE assignedSmallId = 0;
+
+			if (!WinsockNetLayer::JoinSplitScreen(padIdx, &assignedSmallId))
+			{
+				app.DebugPrintf("Split-screen pad %d: failed to open TCP to host\n", padIdx);
+				pMinecraft->connectionDisconnected(padIdx, DisconnectPacket::eDisconnect_ConnectionCreationFailed);
+				return;
+			}
+
+			// Update the local IQNetPlayer (at pad index) with the host-assigned smallId.
+			// The NetworkPlayerXbox created by NotifyPlayerJoined already points to
+			// m_player[padIdx], so we just set the smallId for network routing.
+			IQNet::m_player[padIdx].m_smallId = assignedSmallId;
+			IQNet::m_player[padIdx].m_resolvedXuid = Win64Xuid::DeriveXuidForPad(Win64Xuid::ResolvePersistentXuid(), padIdx);
+
+			// Network socket (not hostLocal) — data goes through TCP via GetLocalSocket
+			socket = new Socket(pNetworkPlayer, false, false);
+			pNetworkPlayer->SetSocket(socket);
+
+			ClientConnection* connection = new ClientConnection(pMinecraft, socket, padIdx);
+			if (connection->createdOk)
+			{
+				connection->send(shared_ptr<PreLoginPacket>(new PreLoginPacket(pNetworkPlayer->GetOnlineName())));
+				pMinecraft->addPendingLocalConnection(padIdx, connection);
+			}
+			else
+			{
+				pMinecraft->connectionDisconnected(padIdx, DisconnectPacket::eDisconnect_ConnectionCreationFailed);
+				delete connection;
+			}
+			return;
+		}
+#endif
+
 		socket = new Socket( pNetworkPlayer, g_NetworkManager.IsHost(), g_NetworkManager.IsHost() && localPlayer );
 		pNetworkPlayer->SetSocket( socket );
 
diff --git a/Minecraft.Client/Common/Network/PlatformNetworkManagerStub.cpp b/Minecraft.Client/Common/Network/PlatformNetworkManagerStub.cpp
index 44ca3c2f..3d088935 100644
--- a/Minecraft.Client/Common/Network/PlatformNetworkManagerStub.cpp
+++ b/Minecraft.Client/Common/Network/PlatformNetworkManagerStub.cpp
@@ -243,10 +243,16 @@ void CPlatformNetworkManagerStub::DoWork()
 				if (IQNet::s_playerCount > 1)
 					IQNet::s_playerCount--;
 			}
-			// Always return smallId to the free pool so it can be reused (game may have already cleared the slot).
-			WinsockNetLayer::PushFreeSmallId(disconnectedSmallId);
-			// Clear O(1) socket lookup so GetSocketForSmallId stays fast (s_connections never shrinks).
-			WinsockNetLayer::ClearSocketForSmallId(disconnectedSmallId);
+			// NOTE: Do NOT call PushFreeSmallId here. The old PlayerConnection's
+			// write thread may still be alive (it dies in PlayerList::tick when
+			// m_smallIdsToClose is processed). If we recycle the smallId now,
+			// AcceptThread can reuse it for a new connection, and the old write
+			// thread's getPlayer() lookup will resolve to the NEW player, sending
+			// stale game packets to the new client's TCP socket — corrupting its
+			// login handshake (bad packet id crash). PushFreeSmallId and
+			// ClearSocketForSmallId are called from PlayerList::tick after the
+			// old Connection threads are dead.
+			//
 			// Clear chunk visibility flags for this system so rejoin gets fresh chunk state.
 			SystemFlagRemoveBySmallId((int)disconnectedSmallId);
 		}
@@ -289,12 +295,40 @@ int CPlatformNetworkManagerStub::GetLocalPlayerMask(int playerIndex)
 
 bool CPlatformNetworkManagerStub::AddLocalPlayerByUserIndex( int userIndex )
 {
-	NotifyPlayerJoined(m_pIQNet->GetLocalPlayerByUserIndex(userIndex));
-	return ( m_pIQNet->AddLocalPlayerByUserIndex(userIndex) == S_OK );
+	if ( m_pIQNet->AddLocalPlayerByUserIndex(userIndex) != S_OK )
+		return false;
+	// Player is now registered in IQNet — get a pointer and notify the network layer.
+	// Use the static array directly: GetLocalPlayerByUserIndex checks customData which
+	// isn't set until addNetworkPlayer runs inside NotifyPlayerJoined.
+	NotifyPlayerJoined(&IQNet::m_player[userIndex]);
+	return true;
 }
 
 bool CPlatformNetworkManagerStub::RemoveLocalPlayerByUserIndex( int userIndex )
 {
+#ifdef _WINDOWS64
+	if (userIndex > 0 && userIndex < XUSER_MAX_COUNT && !m_pIQNet->IsHost())
+	{
+		IQNetPlayer* qp = &IQNet::m_player[userIndex];
+
+		// Notify the network layer before clearing the slot
+		if (qp->GetCustomDataValue() != 0)
+		{
+			NotifyPlayerLeaving(qp);
+		}
+
+		// Close the split-screen TCP connection and reset WinsockNetLayer state
+		WinsockNetLayer::CloseSplitScreenConnection(userIndex);
+
+		// Clear the IQNet slot so it can be reused on rejoin
+		qp->m_smallId = 0;
+		qp->m_isRemote = false;
+		qp->m_isHostPlayer = false;
+		qp->m_resolvedXuid = INVALID_XUID;
+		qp->m_gamertag[0] = 0;
+		qp->SetCustomDataValue(0);
+	}
+#endif
 	return true;
 }