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

8 files changed, 129 insertions, 12 deletions

diff --git a/builtin/common/misc_helpers.lua b/builtin/common/misc_helpers.lua
index d9ebc39c3..39fca7d1e 100644
--- a/builtin/common/misc_helpers.lua
+++ b/builtin/common/misc_helpers.lua
@@ -564,7 +564,7 @@ if INIT == "mainmenu" then
 		return nil
 	end
 
-	function fgettext(text, ...)
+	function fgettext_ne(text, ...)
 		text = core.gettext(text)
 		local arg = {n=select('#', ...), ...}
 		if arg.n >= 1 then
@@ -586,7 +586,11 @@ if INIT == "mainmenu" then
 			end
 			text = result
 		end
-		return core.formspec_escape(text)
+		return text
+	end
+
+	function fgettext(text, ...)
+		return core.formspec_escape(fgettext_ne(text, ...))
 	end
 end
 
diff --git a/builtin/mainmenu/common.lua b/builtin/mainmenu/common.lua
index 549c0967b..f32d77f2a 100644
--- a/builtin/mainmenu/common.lua
+++ b/builtin/mainmenu/common.lua
@@ -16,10 +16,16 @@
 --51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 --------------------------------------------------------------------------------
 -- Global menu data
----------------------------------------------------------------------------------
+--------------------------------------------------------------------------------
 menudata = {}
 
 --------------------------------------------------------------------------------
+-- Local cached values
+--------------------------------------------------------------------------------
+local min_supp_proto = core.get_min_supp_proto()
+local max_supp_proto = core.get_max_supp_proto()
+
+--------------------------------------------------------------------------------
 -- Menu helper functions
 --------------------------------------------------------------------------------
 
@@ -43,6 +49,25 @@ function image_column(tooltip, flagname)
 end
 
 --------------------------------------------------------------------------------
+function order_favorite_list(list)
+	local res = {}
+	--orders the favorite list after support
+	for i=1,#list,1 do
+		local fav = list[i]
+		if is_server_protocol_compat(fav.proto_min, fav.proto_max) then
+			table.insert(res, fav)
+		end
+	end
+	for i=1,#list,1 do
+		local fav = list[i]
+		if not is_server_protocol_compat(fav.proto_min, fav.proto_max) then
+			table.insert(res, fav)
+		end
+	end
+	return res
+end
+
+--------------------------------------------------------------------------------
 function render_favorite(spec,render_details)
 	local text = ""
 
@@ -68,6 +93,7 @@ function render_favorite(spec,render_details)
 	end
 
 	local details = ""
+	local grey_out = not is_server_protocol_compat(spec.proto_max, spec.proto_min)
 
 	if spec.clients ~= nil and spec.clients_max ~= nil then
 		local clients_color = ''
@@ -87,11 +113,17 @@ function render_favorite(spec,render_details)
 			clients_color = '#ffba97' -- 90-100%: orange
 		end
 
+		if grey_out then
+			clients_color = '#aaaaaa'
+		end
+
 		details = details ..
 				clients_color .. ',' ..
 				render_client_count(spec.clients) .. ',' ..
 				'/,' ..
 				render_client_count(spec.clients_max) .. ','
+	elseif grey_out then
+		details = details .. '#aaaaaa,?,/,?,'
 	else
 		details = details .. ',?,/,?,'
 	end
@@ -114,7 +146,7 @@ function render_favorite(spec,render_details)
 		details = details .. "0,"
 	end
 
-	return details .. text
+	return details .. (grey_out and '#aaaaaa,' or ',') .. text
 end
 
 --------------------------------------------------------------------------------
@@ -195,7 +227,7 @@ function asyncOnlineFavourites()
 		nil,
 		function(result)
 			if core.setting_getbool("public_serverlist") then
-				menudata.favorites = result
+				menudata.favorites = order_favorite_list(result)
 				core.event_handler("Refresh")
 			end
 		end
@@ -225,3 +257,21 @@ function text2textlist(xpos,ypos,width,height,tl_name,textlen,text,transparency)
 
 	return retval
 end
+
+--------------------------------------------------------------------------------
+function is_server_protocol_compat(proto_min, proto_max)
+	return not ((min_supp_proto > (proto_max or 24)) or (max_supp_proto < (proto_min or 13)))
+end
+--------------------------------------------------------------------------------
+function is_server_protocol_compat_or_error(proto_min, proto_max)
+	if not is_server_protocol_compat(proto_min, proto_max) then
+		gamedata.errormessage = fgettext_ne("Protocol version mismatch, server " ..
+			((proto_min ~= proto_max) and "supports protocols between $1 and $2" or "enforces protocol version $1") ..
+			", we " ..
+			((min_supp_proto ~= max_supp_proto) and "support protocols between version $3 and $4." or "only support protocol version $3"),
+			proto_min or 13, proto_max or 24, min_supp_proto, max_supp_proto)
+		return false
+	end
+
+	return true
+end
diff --git a/builtin/mainmenu/tab_multiplayer.lua b/builtin/mainmenu/tab_multiplayer.lua
index f4c5b22b0..570259718 100644
--- a/builtin/mainmenu/tab_multiplayer.lua
+++ b/builtin/mainmenu/tab_multiplayer.lua
@@ -62,6 +62,7 @@ local function get_formspec(tabview, name, tabdata)
 			image_column(fgettext("Creative mode"), "creative") .. ",padding=1;" ..
 			image_column(fgettext("Damage enabled"), "damage") .. ",padding=0.25;" ..
 			image_column(fgettext("PvP enabled"), "pvp") .. ",padding=0.25;" ..
+			"color,span=1;" ..
 			"text,padding=1]"                               -- name
 	else
 		retval = retval .. "tablecolumns[text]"
@@ -88,7 +89,6 @@ end
 
 --------------------------------------------------------------------------------
 local function main_button_handler(tabview, fields, name, tabdata)
-
 	if fields["te_name"] ~= nil then
 		gamedata.playername = fields["te_name"]
 		core.setting_set("name", fields["te_name"])
@@ -98,6 +98,10 @@ local function main_button_handler(tabview, fields, name, tabdata)
 		local event = core.explode_table_event(fields["favourites"])
 		if event.type == "DCL" then
 			if event.row <= #menudata.favorites then
+				if not is_server_protocol_compat_or_error(menudata.favorites[event.row].proto_min,
+						menudata.favorites[event.row].proto_max) then
+					return true
+				end
 				gamedata.address    = menudata.favorites[event.row].address
 				gamedata.port       = menudata.favorites[event.row].port
 				gamedata.playername = fields["te_name"]
@@ -189,7 +193,7 @@ local function main_button_handler(tabview, fields, name, tabdata)
 		local current_favourite = core.get_table_index("favourites")
 		if current_favourite == nil then return end
 		core.delete_favorite(current_favourite)
-		menudata.favorites   = core.get_favorites()
+		menudata.favorites = order_favorite_list(core.get_favorites())
 		tabdata.fav_selected = nil
 
 		core.setting_set("address","")
@@ -215,6 +219,11 @@ local function main_button_handler(tabview, fields, name, tabdata)
 
 			gamedata.servername        = menudata.favorites[fav_idx].name
 			gamedata.serverdescription = menudata.favorites[fav_idx].description
+
+			if not is_server_protocol_compat_or_error(menudata.favorites[fav_idx].proto_min,
+					menudata.favorites[fav_idx].proto_max)then
+				return true
+			end
 		else
 			gamedata.servername        = ""
 			gamedata.serverdescription = ""
diff --git a/builtin/mainmenu/tab_simple_main.lua b/builtin/mainmenu/tab_simple_main.lua
index 87bd551c0..b9a6b650f 100644
--- a/builtin/mainmenu/tab_simple_main.lua
+++ b/builtin/mainmenu/tab_simple_main.lua
@@ -45,6 +45,7 @@ local function get_formspec(tabview, name, tabdata)
 			image_column(fgettext("Creative mode"), "creative") .. ",padding=1;" ..
 			image_column(fgettext("Damage enabled"), "damage") .. ",padding=0.25;" ..
 			image_column(fgettext("PvP enabled"), "pvp") .. ",padding=0.25;" ..
+			"color,span=1;" ..
 			"text,padding=1]"                               -- name
 	else
 		retval = retval .. "tablecolumns[text]"
@@ -87,7 +88,6 @@ local function get_formspec(tabview, name, tabdata)
 end
 
 --------------------------------------------------------------------------------
-
 local function main_button_handler(tabview, fields, name, tabdata)
 
 	if fields["btn_start_singleplayer"] then
@@ -159,6 +159,11 @@ local function main_button_handler(tabview, fields, name, tabdata)
 
 			gamedata.servername			= menudata.favorites[fav_idx].name
 			gamedata.serverdescription	= menudata.favorites[fav_idx].description
+
+			if not is_server_protocol_compat_or_error(menudata.favorites[fav_idx].proto_min,
+					menudata.favorites[fav_idx].proto_max) then
+				return true
+			end
 		else
 			gamedata.servername			= ""
 			gamedata.serverdescription	= ""
diff --git a/doc/menu_lua_api.txt b/doc/menu_lua_api.txt
index 5c0f90df6..f76124a0d 100644
--- a/doc/menu_lua_api.txt
+++ b/doc/menu_lua_api.txt
@@ -197,9 +197,11 @@ core.delete_world(index)
 Helpers:
 core.gettext(string) -> string
 ^ look up the translation of a string in the gettext message catalog
-fgettext(string, ...) -> string
+fgettext_ne(string, ...)
 ^ call core.gettext(string), replace "$1"..."$9" with the given
-^ extra arguments, call core.formspec_escape and return the result
+^ extra arguments and return the result
+fgettext(string, ...) -> string
+^ same as fgettext_ne(), but calls core.formspec_escape before returning result
 core.parse_json(string[, nullvalue]) -> something (possible in async calls)
 ^ see core.parse_json (lua_api.txt)
 dump(obj, dumped={})
@@ -211,6 +213,12 @@ string:trim()
 core.is_yes(arg) (possible in async calls)
 ^ returns whether arg can be interpreted as yes
 
+Version compat:
+core.get_min_supp_proto()
+^ returns the minimum supported network protocol version
+core.get_max_supp_proto()
+^ returns the maximum supported network protocol version
+
 Async:
 core.handle_async(async_job,parameters,finished)
 ^ execute a function asynchronously
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");