Adding Engine Version and Mod name/version checks to multiplayer handshake.

Incrementing protocol version as handshake messages have changed.
2025-01-05 18:30:38 +01:00
parent 60d388804a
commit 5b98a647dc
10 changed files with 204 additions and 20 deletions
@@ -0,0 +1,56 @@
+/* Copyright (C) 2025 Wildfire Games.
+ * This file is part of 0 A.D.
+ *
+ * 0 A.D. is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 0 A.D. is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "precompiled.h"
+
+#include "NetProtocol.h"
+
+namespace
+{
+template <typename ModType>
+std::string GetModName(const ModType& mod)
+{
+	return mod.m_Name + "-" + mod.m_Version;
+}
+}
+
+std::optional<HandshakeError> CheckHandshake(const CSrvHandshakeMessage& serverMessage, const CCliHandshakeMessage& clientMessage)
+{
+	if (serverMessage.m_EngineVersion != clientMessage.m_EngineVersion)
+		return HandshakeError{"engine", clientMessage.m_EngineVersion, serverMessage.m_EngineVersion};
+
+	const auto& serverMods = serverMessage.m_EnabledMods;
+	const auto& clientMods = clientMessage.m_EnabledMods;
+
+	for (uint32_t i = 0; i < std::max(clientMods.size(), serverMods.size()); ++i)
+	{
+		if (i >= serverMods.size())
+			return HandshakeError{"mod", GetModName(clientMods[i]), ""};
+
+		if (i >= clientMods.size())
+			return HandshakeError{"mod", "", GetModName(serverMods[i])};
+
+		const std::string serverMod = GetModName(serverMods[i]);
+		const std::string clientMod = GetModName(clientMods[i]);
+
+		// Client and server have different mods enabled, or mods enabled in a different order
+		if (clientMod != serverMod)
+			return HandshakeError{"mod", clientMod, serverMod};
+	}
+
+	return {};
+}