engine: server: check if we got info request from master server, that acts as a bridge for NAT servers

engine/server/sv_client.c

@@ -3116,17 +3116,12 @@ void SV_ConnectionlessPacket( netadr_t from, sizebuf_t *msg )
 	else if( !Q_strcmp( pcmd, "s" )) SV_AddToMaster( from, msg );
 	else if( !Q_strcmp( pcmd, "T" "Source" )) SV_TSourceEngineQuery( from );
 	else if( !Q_strcmp( pcmd, "i" )) NET_SendPacket( NS_SERVER, 5, "\xFF\xFF\xFF\xFFj", from ); // A2A_PING
-	else if (!Q_strcmp( pcmd, "c" ))
-	{
-		qboolean sv_nat = Cvar_VariableInteger( "sv_nat" );
-		if( sv_nat )
+	else if( !Q_strcmp( pcmd, "c" ) && Cvar_VariableInteger( "sv_nat" ) && NET_IsFromMasters( from ))
 	{
 		netadr_t to;
-
 		if( NET_StringToAdr( Cmd_Argv( 1 ), &to ) && !NET_IsReservedAdr( to ))
 			SV_Info( to, PROTOCOL_VERSION );
 	}
-	}
 	else if( svgame.dllFuncs.pfnConnectionlessPacket( &from, args, buf, &len ))
 	{
 		// user out of band message (must be handled in CL_ConnectionlessPacket)