Server: announce MIN/MAX protocol version supported to serverlist. Client: check serverlist

Client now informs about incompatible servers from the list, this permits to prevent the protocol movements.
Server announces its supported protocol versions to master server

3 files changed, 43 insertions, 2 deletions

diff --git a/src/script/lua_api/l_mainmenu.cpp b/src/script/lua_api/l_mainmenu.cpp
index 0d8365106..2bed2a255 100644
--- a/src/script/lua_api/l_mainmenu.cpp
+++ b/src/script/lua_api/l_mainmenu.cpp
@@ -472,6 +472,7 @@ int ModApiMainMenu::l_get_favorites(lua_State *L)
 
 	for (unsigned int i = 0; i < servers.size(); i++)
 	{
+
 		lua_pushnumber(L,index);
 
 		lua_newtable(L);
@@ -509,6 +510,18 @@ int ModApiMainMenu::l_get_favorites(lua_State *L)
 			lua_settable(L, top_lvl2);
 		}
 
+		if (servers[i]["proto_min"].asString().size()) {
+			lua_pushstring(L,"proto_min");
+			lua_pushinteger(L,servers[i]["proto_min"].asInt());
+			lua_settable(L, top_lvl2);
+		}
+
+		if (servers[i]["proto_max"].asString().size()) {
+			lua_pushstring(L,"proto_max");
+			lua_pushinteger(L,servers[i]["proto_max"].asInt());
+			lua_settable(L, top_lvl2);
+		}
+
 		if (servers[i]["password"].asString().size()) {
 			lua_pushstring(L,"password");
 			lua_pushboolean(L,servers[i]["password"].asBool());
@@ -1083,6 +1096,19 @@ int ModApiMainMenu::l_get_screen_info(lua_State *L)
 }
 
 /******************************************************************************/
+int ModApiMainMenu::l_get_min_supp_proto(lua_State *L)
+{
+	lua_pushinteger(L, CLIENT_PROTOCOL_VERSION_MIN);
+	return 1;
+}
+
+int ModApiMainMenu::l_get_max_supp_proto(lua_State *L)
+{
+	lua_pushinteger(L, CLIENT_PROTOCOL_VERSION_MAX);
+	return 1;
+}
+
+/******************************************************************************/
 int ModApiMainMenu::l_do_async_callback(lua_State *L)
 {
 	GUIEngine* engine = getGuiEngine(L);
@@ -1142,6 +1168,8 @@ void ModApiMainMenu::Initialize(lua_State *L, int top)
 	API_FCT(gettext);
 	API_FCT(get_video_drivers);
 	API_FCT(get_screen_info);
+	API_FCT(get_min_supp_proto);
+	API_FCT(get_max_supp_proto);
 	API_FCT(do_async_callback);
 }
 
diff --git a/src/script/lua_api/l_mainmenu.h b/src/script/lua_api/l_mainmenu.h
index ff61dd97a..8b21a93aa 100644
--- a/src/script/lua_api/l_mainmenu.h
+++ b/src/script/lua_api/l_mainmenu.h
@@ -137,6 +137,12 @@ private:
 
 	static int l_get_video_drivers(lua_State *L);
 
+	//version compatibility
+	static int l_get_min_supp_proto(lua_State *L);
+
+	static int l_get_max_supp_proto(lua_State *L);
+
+
 	// async
 	static int l_do_async_callback(lua_State *L);
 
diff --git a/src/serverlist.cpp b/src/serverlist.cpp
index 472a6b85c..a3353340e 100644
--- a/src/serverlist.cpp
+++ b/src/serverlist.cpp
@@ -28,6 +28,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "filesys.h"
 #include "porting.h"
 #include "log.h"
+#include "network/networkprotocol.h"
 #include "json/json.h"
 #include "convert_json.h"
 #include "httpfetch.h"
@@ -67,8 +68,11 @@ std::vector<ServerListSpec> getLocal()
 
 std::vector<ServerListSpec> getOnline()
 {
-	Json::Value root = fetchJsonValue(
-			(g_settings->get("serverlist_url") + "/list").c_str(), NULL);
+	std::ostringstream geturl;
+	geturl << g_settings->get("serverlist_url") <<
+		"/list?proto_version_min=" << CLIENT_PROTOCOL_VERSION_MIN <<
+		"&proto_version_max=" << CLIENT_PROTOCOL_VERSION_MAX;
+	Json::Value root = fetchJsonValue(geturl.str(), NULL);
 
 	std::vector<ServerListSpec> server_list;
 
@@ -205,9 +209,12 @@ void sendAnnounce(const std::string &action,
 		server["address"] = g_settings->get("server_address");
 	}
 	if (action != "delete") {
+		bool strict_checking = g_settings->getBool("strict_protocol_version_checking");
 		server["name"]         = g_settings->get("server_name");
 		server["description"]  = g_settings->get("server_description");
 		server["version"]      = minetest_version_simple;
+		server["proto_min"]    = strict_checking ? LATEST_PROTOCOL_VERSION : SERVER_PROTOCOL_VERSION_MIN;
+		server["proto_max"]    = strict_checking ? LATEST_PROTOCOL_VERSION : SERVER_PROTOCOL_VERSION_MAX;
 		server["url"]          = g_settings->get("server_url");
 		server["creative"]     = g_settings->getBool("creative_mode");
 		server["damage"]       = g_settings->getBool("enable_damage");