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#include <Columns/ColumnString.h>
#include <Columns/ColumnArray.h>
#include <Functions/FunctionFactory.h>
#include <Functions/IFunction.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypeArray.h>
#include <Common/DNSResolver.h>
#include <Poco/Net/IPAddress.h>
#include <Interpreters/Context.h>
#include <Poco/Util/AbstractConfiguration.h>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int BAD_ARGUMENTS;
extern const int FUNCTION_NOT_ALLOWED;
}
class ReverseDNSQuery : public IFunction
{
public:
static constexpr auto name = "reverseDNSQuery";
static constexpr auto allow_function_config_name = "allow_reverse_dns_query_function";
static FunctionPtr create(ContextPtr)
{
return std::make_shared<ReverseDNSQuery>();
}
String getName() const override
{
return name;
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & data_type, size_t input_rows_count) const override
{
if (!Context::getGlobalContextInstance()->getConfigRef().getBool(allow_function_config_name, false))
{
throw Exception(ErrorCodes::FUNCTION_NOT_ALLOWED, "Function {} is not allowed because {} is not set", name, allow_function_config_name);
}
if (arguments.empty())
{
throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH, "Function {} requires at least one argument", name);
}
auto res_type = getReturnTypeImpl({data_type});
if (input_rows_count == 0u)
{
return res_type->createColumnConstWithDefaultValue(input_rows_count);
}
if (!isString(arguments[0].type))
{
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Function {} requires the input column to be of type String", name);
}
auto input_column = arguments[0].column;
auto ip_address = Poco::Net::IPAddress(input_column->getDataAt(0).toString());
auto ptr_records = DNSResolver::instance().reverseResolve(ip_address);
if (ptr_records.empty())
return res_type->createColumnConstWithDefaultValue(input_rows_count);
Array res;
for (const auto & ptr_record : ptr_records)
{
res.push_back(ptr_record);
}
return res_type->createColumnConst(input_rows_count, res);
}
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override
{
return false;
}
size_t getNumberOfArguments() const override
{
return 1u;
}
DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override
{
return std::make_shared<DataTypeArray>(std::make_shared<DataTypeString>());
}
};
REGISTER_FUNCTION(ReverseDNSQuery)
{
factory.registerFunction<ReverseDNSQuery>(
FunctionDocumentation{
.description = R"(Performs a reverse DNS query to get the PTR records associated with the IP address)",
.syntax = "reverseDNSQuery(address)",
.arguments = {{"address", "An IPv4 or IPv6 address. [String](../../sql-reference/data-types/string.md)"}},
.returned_value = "Associated domains (PTR records). [String](../../sql-reference/data-types/string.md).",
.examples = {{"",
"SELECT reverseDNSQuery('192.168.0.2');",
R"(
┌─reverseDNSQuery('192.168.0.2')────────────┐
│ ['test2.example.com','test3.example.com'] │
└───────────────────────────────────────────┘
)"}}
}
);
}
}
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