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// Copyright (C) 2016-2022 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef SIMPLE_PARSER_H
#define SIMPLE_PARSER_H
#include <asiolink/io_address.h>
#include <cc/data.h>
#include <cc/dhcp_config_error.h>
#include <util/triplet.h>
#include <map>
#include <vector>
#include <string>
#include <stdint.h>
#include <limits>
namespace isc {
namespace data {
/// This array defines a single entry of default values.
struct SimpleDefault {
SimpleDefault(const char* name, isc::data::Element::types type, const char* value)
:name_(name), type_(type), value_(value) {}
std::string name_;
const isc::data::Element::types type_;
const char* value_;
};
/// This specifies all required keywords.
typedef std::vector<std::string> SimpleRequiredKeywords;
/// This specifies all accepted keywords with their types.
typedef std::map<std::string, isc::data::Element::types> SimpleKeywords;
/// This specifies all default values in a given scope (e.g. a subnet).
typedef std::vector<SimpleDefault> SimpleDefaults;
/// This defines a list of all parameters that are derived (or inherited) between
/// contexts.
typedef std::vector<std::string> ParamsList;
/// @brief A simple parser
///
/// This class is intended to be a simpler replacement for DhcpConfigParser.
/// This class has been initially created to facilitate DHCPv4 and
/// DHCPv6 servers' configuration parsing. Thus examples provided
/// herein are related to DHCP configuration. Nevertheless, this is a
/// generic class to be used in other modules too.
///
/// The simplification comes from several factors:
/// - no build/commit nonsense. There's a single step:
/// CfgStorage parse(ConstElementPtr json)
/// that converts JSON configuration into an object and returns it.
/// - no state kept. This greatly simplifies the parsers (no contexts, no child
/// parsers list, no separate storage for uint32, strings etc. In fact,
/// this base class is purely static. However, some derived classes may store
/// some state. Implementors are advised to store as little state as possible.
/// - no optional parameters (all are mandatory). This simplifies the parser,
/// but introduces a new step before parsing where we insert the default
/// values into client configuration before parsing. This is actually a good
/// thing, because we now have a clear picture of the default parameters as
/// they're defined in a single place (the DhcpConfigParser had the defaults
/// spread out in multiple files in multiple directories).
class SimpleParser {
public:
/// @brief Checks that all required keywords are present.
///
/// This method throws an exception when a required
/// entry is not present in the given scope.
///
/// @param required Required keywords.
/// @param scope Specified parameters which are checked.
/// @throw DhcpConfigError if a required parameter is not present.
static void checkRequired(const SimpleRequiredKeywords& required,
isc::data::ConstElementPtr scope);
/// @brief Checks acceptable keywords with their expected type.
///
/// This methods throws an exception when a not acceptable keyword
/// is found or when an acceptable entry does not have the expected type.
///
/// @param keywords The @c SimpleKeywords keywords and types map.
/// @param scope Specified parameters which are checked.
/// @throw DhcpConfigError if a not acceptable keyword is found.
/// @throw DhcpConfigError if an acceptable entry does not have
/// the expected type.
static void checkKeywords(const SimpleKeywords& keywords,
isc::data::ConstElementPtr scope);
/// @brief Derives (inherits) parameters from parent scope to a child
///
/// This method derives parameters from the parent scope to the child,
/// if there are no values specified in the child scope. For example,
/// this method can be used to derive timers from global scope (e.g. for
/// the whole DHCPv6 server) to a subnet scope. This method checks
/// if the child scope doesn't have more specific values defined. If
/// it doesn't, then the value from parent scope is copied over.
///
/// @param parent scope to copy from (e.g. global)
/// @param child scope to copy from (e.g. subnet)
/// @param params names of the parameters to copy
/// @return number of parameters copied
static size_t deriveParams(isc::data::ConstElementPtr parent,
isc::data::ElementPtr child,
const ParamsList& params);
/// @brief Sets the default values
///
/// This method sets the default values for parameters that are not
/// defined. The list of default values is specified by default_values.
/// If not present, those will be inserted into the scope. If
/// a parameter is already present, the default value will not
/// be inserted.
///
/// @param scope default values will be inserted here
/// @param default_values list of default values
/// @return number of parameters inserted
static size_t setDefaults(isc::data::ElementPtr scope,
const SimpleDefaults& default_values);
/// @brief Sets the default values for all entries in a list
///
/// This is a simple utility method that iterates over all
/// parameters in a list and calls setDefaults for each
/// entry.
///
/// @param list list to be iterated over
/// @param default_values list of default values
/// @return number of parameters inserted
static size_t setListDefaults(isc::data::ConstElementPtr list,
const SimpleDefaults& default_values);
/// @brief Utility method that returns position of an element
///
/// It's mostly useful for logging. If the element is missing
/// the parent position is returned or ZERO_POSITION if parent
/// is null.
///
/// @param name position of that element will be returned
/// @param parent parent element (optional)
/// @return position of the element specified.
static const data::Element::Position&
getPosition(const std::string& name, const data::ConstElementPtr parent);
/// @brief Returns a string parameter from a scope
///
/// Unconditionally returns a parameter.
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return a string value of the parameter
/// @throw DhcpConfigError if the parameter is not there or is not of
/// appropriate type
static std::string getString(isc::data::ConstElementPtr scope,
const std::string& name);
/// @brief Returns an integer parameter from a scope
///
/// Unconditionally returns a parameter.
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return an integer value of the parameter
/// @throw DhcpConfigError if the parameter is not there or is not of
/// appropriate type
static int64_t getInteger(isc::data::ConstElementPtr scope,
const std::string& name);
/// @brief Returns an integer parameter from a scope and checks its range
///
/// Unconditionally returns a parameter. Checks that the value specified
/// is in min =< X =< max range.
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @param min minimum allowed value
/// @param max maximum allowed value
/// @return an integer value of the parameter
/// @throw DhcpConfigError if the parameter is not there or is not of
/// appropriate type.
/// @throw OutOfRange if the parameter is out of range
static int64_t getInteger(isc::data::ConstElementPtr scope,
const std::string& name,
int64_t min, int64_t max);
/// @brief Returns a boolean parameter from a scope
///
/// Unconditionally returns a parameter.
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return a boolean value of the parameter
/// @throw DhcpConfigError if the parameter is not there or is not of
/// appropriate type
static bool getBoolean(isc::data::ConstElementPtr scope,
const std::string& name);
/// @brief Returns a IOAddress parameter from a scope
///
/// Unconditionally returns a parameter.
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return an IOAddress representing the value of the parameter
/// @throw DhcpConfigError if the parameter is not there or is not of
/// appropriate type (or its conversion to IOAddress fails due to not
/// being a proper address).
static isc::asiolink::IOAddress
getAddress(const ConstElementPtr& scope, const std::string& name);
/// @brief Returns a floating point parameter from a scope
///
/// Unconditionally returns a parameter.
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return a double value of the parameter
/// @throw DhcpConfigError if the parameter is not there or is not
/// an Element::real
static double getDouble(const ConstElementPtr& scope,
const std::string& name);
protected:
/// @brief Returns an integer value with range checking from a scope
///
/// This template should be instantiated in parsers when useful
///
/// @tparam int_type the integer type e.g. uint32_t
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter for error report
/// @return a value of int_type
/// @throw DhcpConfigError if the parameter is not there, is not of
/// appropriate type or is out of type value range
template <typename int_type> int_type
getIntType(isc::data::ConstElementPtr scope,
const std::string& name) {
int64_t val_int = getInteger(scope, name);
if ((val_int < std::numeric_limits<int_type>::min()) ||
(val_int > std::numeric_limits<int_type>::max())) {
isc_throw(isc::dhcp::DhcpConfigError,
"out of range value (" << val_int
<< ") specified for parameter '" << name
<< "' (" << getPosition(name, scope) << ")");
}
return (static_cast<int_type>(val_int));
}
/// @brief Returns a converted value from a scope
///
/// This template should be instantiated in parsers when useful
///
/// @tparam target_type the type of the result
/// @tparam convert the conversion function std::string -> target_type
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter for error report
/// @param type_name name of target_type for error report
/// @return a converted value of target_type
/// @throw DhcpConfigError if the parameter is not there, is not of
/// appropriate type or can not be converted
template <typename target_type,
target_type convert(const std::string&)> target_type
getAndConvert(isc::data::ConstElementPtr scope,
const std::string& name,
const std::string& type_name) {
std::string str = getString(scope, name);
try {
return (convert(str));
} catch (const std::exception&) {
isc_throw(isc::dhcp::DhcpConfigError,
"invalid " << type_name << " (" << str
<< ") specified for parameter '" << name
<< "' (" << getPosition(name, scope) << ")");
}
}
public:
/// @brief Returns a value converted to uint32_t
///
/// Instantiation of getIntType() to uint32_t
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return an uint32_t value
/// @throw isc::dhcp::DhcpConfigError when it is not an uint32_t
uint32_t getUint32(isc::data::ConstElementPtr scope,
const std::string& name) {
return (getIntType<uint32_t>(scope, name));
}
/// @brief Returns a value converted to uint16_t
///
/// Instantiation of getIntType() to uint16_t
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return an uint16_t value
/// @throw isc::dhcp::DhcpConfigError when it is not an uint16_t
uint16_t getUint16(isc::data::ConstElementPtr scope,
const std::string& name) {
return (getIntType<uint16_t>(scope, name));
}
/// @brief Get an uint8_t value
///
/// Instantiation of getIntType() to uint8_t
///
/// @param scope specified parameter will be extracted from this scope
/// @param name name of the parameter
/// @return uint8_t value
/// @throw isc::dhcp::DhcpConfigError when it is not an uint8_t
uint8_t getUint8(ConstElementPtr scope, const std::string& name) {
return (getIntType<uint8_t>(scope, name));
}
/// @brief Parses an integer triplet
///
/// Parses an integer triplet parameter of the form:
///
/// min-{name}, {name}, max-{name}
///
/// @param scope Data element holding e.g. shared network configuration
/// to be parsed.
/// @param name Base name of the parameter.
/// @return A triplet with the parsed value.
const isc::util::Triplet<uint32_t> parseIntTriplet(const data::ConstElementPtr& scope,
const std::string& name);
};
}
}
#endif
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