[CSM] Add flavour limits controlled by server (#5930)

* [CSM] Add flavour limits controlled by server

Server send flavour limits to client permitting to disable or limit some Lua calls

* Add limits for reading nodedefs and itemdefs

* flavour: Add lookup node limits

* Merge get_node_or_nil into get_node.

Sending fake node doesn't make sense in CSM, just return nil if node is not available for any reason

* Add node range customization when noderange flavour is enabled (default 8 nodes)

* Limit nodes range & disable chat message sending by default

* Bump protocol version

3 files changed, 22 insertions, 18 deletions

diff --git a/src/script/lua_api/l_client.cpp b/src/script/lua_api/l_client.cpp
index e7d75cce7..6f9240466 100644
--- a/src/script/lua_api/l_client.cpp
+++ b/src/script/lua_api/l_client.cpp
@@ -91,6 +91,11 @@ int ModApiClient::l_send_chat_message(lua_State *L)
 {
 	if (!lua_isstring(L, 1))
 		return 0;
+
+	// If server disabled this API, discard
+	if (getClient(L)->checkCSMFlavourLimit(CSMFlavourLimit::CSM_FL_CHAT_MESSAGES))
+		return 0;
+
 	std::string message = luaL_checkstring(L, 1);
 	getClient(L)->sendChatMessage(utf8_to_wide(message));
 	return 0;
@@ -166,24 +171,11 @@ int ModApiClient::l_gettext(lua_State *L)
 
 // get_node(pos)
 // pos = {x=num, y=num, z=num}
-int ModApiClient::l_get_node(lua_State *L)
-{
-	// pos
-	v3s16 pos = read_v3s16(L, 1);
-	// Do it
-	bool pos_ok;
-	MapNode n = getClient(L)->getNode(pos, &pos_ok);
-	// Return node
-	pushnode(L, n, getClient(L)->ndef());
-	return 1;
-}
-
-// get_node_or_nil(pos)
-// pos = {x=num, y=num, z=num}
 int ModApiClient::l_get_node_or_nil(lua_State *L)
 {
 	// pos
 	v3s16 pos = read_v3s16(L, 1);
+
 	// Do it
 	bool pos_ok;
 	MapNode n = getClient(L)->getNode(pos, &pos_ok);
@@ -290,6 +282,9 @@ int ModApiClient::l_get_item_def(lua_State *L)
 	IItemDefManager *idef = gdef->idef();
 	assert(idef);
 
+	if (getClient(L)->checkCSMFlavourLimit(CSMFlavourLimit::CSM_FL_READ_ITEMDEFS))
+		return 0;
+
 	if (!lua_isstring(L, 1))
 		return 0;
 
@@ -315,6 +310,9 @@ int ModApiClient::l_get_node_def(lua_State *L)
 	if (!lua_isstring(L, 1))
 		return 0;
 
+	if (getClient(L)->checkCSMFlavourLimit(CSMFlavourLimit::CSM_FL_READ_NODEDEFS))
+		return 0;
+
 	const std::string &name = lua_tostring(L, 1);
 	const ContentFeatures &cf = ndef->get(ndef->getId(name));
 	if (cf.name != name) // Unknown node. | name = <whatever>, cf.name = ignore
@@ -363,7 +361,6 @@ void ModApiClient::Initialize(lua_State *L, int top)
 	API_FCT(show_formspec);
 	API_FCT(send_respawn);
 	API_FCT(gettext);
-	API_FCT(get_node);
 	API_FCT(get_node_or_nil);
 	API_FCT(get_wielded_item);
 	API_FCT(disconnect);
diff --git a/src/script/lua_api/l_client.h b/src/script/lua_api/l_client.h
index 7472915f5..8a3c7f0e8 100644
--- a/src/script/lua_api/l_client.h
+++ b/src/script/lua_api/l_client.h
@@ -65,9 +65,6 @@ private:
 	static int l_set_last_run_mod(lua_State *L);
 
 	// get_node(pos)
-	static int l_get_node(lua_State *L);
-
-	// get_node_or_nil(pos)
 	static int l_get_node_or_nil(lua_State *L);
 
 	// get_wielded_item()
diff --git a/src/script/lua_api/l_env.cpp b/src/script/lua_api/l_env.cpp
index 3a4ba89f3..2a57ca59b 100644
--- a/src/script/lua_api/l_env.cpp
+++ b/src/script/lua_api/l_env.cpp
@@ -25,6 +25,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_vmanip.h"
 #include "common/c_converter.h"
 #include "common/c_content.h"
+#include <algorithm>
 #include "scripting_server.h"
 #include "environment.h"
 #include "server.h"
@@ -726,6 +727,15 @@ int ModApiEnvMod::l_find_node_near(lua_State *L)
 	}
 
 	int start_radius = (lua_toboolean(L, 4)) ? 0 : 1;
+
+#ifndef SERVER
+	// Client API limitations
+	if (getClient(L) &&
+			getClient(L)->checkCSMFlavourLimit(CSMFlavourLimit::CSM_FL_LOOKUP_NODES)) {
+		radius = std::max<int>(radius, getClient(L)->getCSMNodeRangeLimit());
+	}
+#endif
+
 	for (int d = start_radius; d <= radius; d++) {
 		std::vector<v3s16> list = FacePositionCache::getFacePositions(d);
 		for (std::vector<v3s16>::iterator i = list.begin();