Add 'on_prejoinplayer' callback

builtin/misc_register.lua

@@ -380,6 +380,7 @@ minetest.registered_on_generateds, minetest.register_on_generated = make_registr
 minetest.registered_on_newplayers, minetest.register_on_newplayer = make_registration()
 minetest.registered_on_dieplayers, minetest.register_on_dieplayer = make_registration()
 minetest.registered_on_respawnplayers, minetest.register_on_respawnplayer = make_registration()
+minetest.registered_on_prejoinplayers, minetest.register_on_prejoinplayer = make_registration()
 minetest.registered_on_joinplayers, minetest.register_on_joinplayer = make_registration()
 minetest.registered_on_leaveplayers, minetest.register_on_leaveplayer = make_registration()
 minetest.registered_on_player_receive_fields, minetest.register_on_player_receive_fields = make_registration_reverse()

doc/lua_api.txt

@@ -1175,6 +1175,9 @@ minetest.register_on_respawnplayer(func(ObjectRef))
 ^ Called when player is to be respawned
 ^ Called _before_ repositioning of player occurs
 ^ return true in func to disable regular player placement
+minetest.register_on_prejoinplayer(func(name, ip))
+^ Called before a player joins the game
+^ If it returns a string, the player is disconnected with that string as reason
 minetest.register_on_joinplayer(func(ObjectRef))
 ^ Called when a player joins the game
 minetest.register_on_leaveplayer(func(ObjectRef))

src/script/cpp_api/s_player.cpp

@@ -19,6 +19,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "cpp_api/s_player.h"
 #include "cpp_api/s_internal.h"
+#include "util/string.h"
 
 void ScriptApiPlayer::on_newplayer(ServerActiveObject *player)
 {
@@ -58,6 +59,23 @@ bool ScriptApiPlayer::on_respawnplayer(ServerActiveObject *player)
 	return positioning_handled_by_some;
 }
 
+bool ScriptApiPlayer::on_prejoinplayer(std::string name, std::string ip, std::string &reason)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	// Get minetest.registered_on_prejoinplayers
+	lua_getglobal(L, "minetest");
+	lua_getfield(L, -1, "registered_on_prejoinplayers");
+	lua_pushstring(L, name.c_str());
+	lua_pushstring(L, ip.c_str());
+	script_run_callbacks(L, 2, RUN_CALLBACKS_MODE_OR);
+	if (lua_isstring(L, -1)) {
+		reason.assign(lua_tostring(L, -1));
+		return true;
+	}
+	return false;
+}
+
 void ScriptApiPlayer::on_joinplayer(ServerActiveObject *player)
 {
 	SCRIPTAPI_PRECHECKHEADER

src/script/cpp_api/s_player.h

@@ -34,6 +34,7 @@ public:
 	void on_newplayer(ServerActiveObject *player);
 	void on_dieplayer(ServerActiveObject *player);
 	bool on_respawnplayer(ServerActiveObject *player);
+	bool on_prejoinplayer(std::string name, std::string ip, std::string &reason);
 	void on_joinplayer(ServerActiveObject *player);
 	void on_leaveplayer(ServerActiveObject *player);
 	void on_cheat(ServerActiveObject *player, const std::string &cheat_type);

src/server.cpp

@@ -1970,6 +1970,19 @@ void Server::ProcessData(u8 *data, u32 datasize, u16 peer_id)
 			return;
 		}
 
+		{
+			std::string reason;
+			if(m_script->on_prejoinplayer(playername, addr_s, reason))
+			{
+				actionstream<<"Server: Player with the name \""<<playername<<"\" "
+						<<"tried to connect from "<<addr_s<<" "
+						<<"but it was disallowed for the following reason: "
+						<<reason<<std::endl;
+				DenyAccess(peer_id, narrow_to_wide(reason.c_str()));
+				return;
+			}
+		}
+
 		infostream<<"Server: New connection: \""<<playername<<"\" from "
 				<<addr_s<<" (peer_id="<<peer_id<<")"<<std::endl;