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kea/src/bin/dhcp6/parser_context.h
2021-03-29 21:47:05 +03:00

406 lines
13 KiB
C++

// Copyright (C) 2015-2021 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 PARSER_CONTEXT_H
#define PARSER_CONTEXT_H
#include <string>
#include <map>
#include <vector>
#include <dhcp6/dhcp6_parser.h>
#include <dhcp6/parser_context_decl.h>
#include <exceptions/exceptions.h>
// Tell Flex the lexer's prototype ...
#define YY_DECL isc::dhcp::Dhcp6Parser::symbol_type parser6_lex (Parser6Context& driver)
// ... and declare it for the parser's sake.
YY_DECL;
namespace isc {
namespace dhcp {
/// @brief Evaluation error exception raised when trying to parse.
///
/// @todo: This probably should be common for Dhcp4 and Dhcp6.
class Dhcp6ParseError : public isc::Exception {
public:
Dhcp6ParseError(const char* file, size_t line, const char* what) :
isc::Exception(file, line, what) { };
};
/// @brief Evaluation context, an interface to the expression evaluation.
class Parser6Context
{
public:
/// @brief Defines currently supported scopes
///
/// Dhcp6Parser is able to parse several types of scope. Usually,
/// when it parses a config file, it expects the data to have a map
/// with Dhcp6 in it and all the parameters within that Dhcp6 map.
/// However, sometimes the parser is expected to parse only a subset
/// of that information. For example, it may be asked to parse
/// a structure that is host-reservation only, without the global
/// 'Dhcp6' or 'reservations' around it. In such case the parser
/// is being told to start parsing as PARSER_HOST_RESERVATION6.
typedef enum {
/// This parser will parse the content as generic JSON.
PARSER_JSON,
/// This parser will parse the content as Dhcp6 config wrapped in a map
/// (that's the regular config file)
PARSER_DHCP6,
/// This parser will parse the content of Dhcp6 (without outer { } and
/// without "Dhcp6"). It is mostly used in unit-tests as most of the
/// unit-tests do not define the outer map and Dhcp6 entity, just the
/// contents of it.
SUBPARSER_DHCP6,
/// This will parse the input as interfaces content.
PARSER_INTERFACES,
/// This will parse the input as Subnet6 content.
PARSER_SUBNET6,
/// This will parse the input as pool6 content.
PARSER_POOL6,
/// This will parse the input as pd-pool content.
PARSER_PD_POOL,
/// This will parse the input as host-reservation.
PARSER_HOST_RESERVATION,
/// This will parse the input option definitions (for tests).
PARSER_OPTION_DEFS,
/// This will parse the input as option definition.
PARSER_OPTION_DEF,
/// This will parse the input as option data.
PARSER_OPTION_DATA,
/// This will parse the input as hooks-library.
PARSER_HOOKS_LIBRARY,
/// This will parse the input as dhcp-ddns. (D2 client config)
PARSER_DHCP_DDNS,
/// This will parse the input as config-control.
PARSER_CONFIG_CONTROL,
} ParserType;
/// @brief Default constructor.
Parser6Context();
/// @brief destructor
virtual ~Parser6Context();
/// @brief JSON elements being parsed.
std::vector<isc::data::ElementPtr> stack_;
/// @brief Method called before scanning starts on a string.
///
/// @param str string to be parsed
/// @param type specifies expected content
void scanStringBegin(const std::string& str, ParserType type);
/// @brief Method called before scanning starts on a file.
///
/// @param f stdio FILE pointer
/// @param filename file to be parsed
/// @param type specifies expected content
void scanFileBegin(FILE* f, const std::string& filename, ParserType type);
/// @brief Method called after the last tokens are scanned.
void scanEnd();
/// @brief Divert input to an include file.
///
/// @param filename file to be included
void includeFile(const std::string& filename);
/// @brief Run the parser on the string specified.
///
/// This method parses specified string. Depending on the value of
/// parser_type, parser may either check only that the input is valid
/// JSON, or may do more specific syntax checking. See @ref ParserType
/// for supported syntax checkers.
///
/// @param str string to be parsed
/// @param parser_type specifies expected content (usually DHCP6 or generic JSON)
/// @return Element structure representing parsed text.
isc::data::ElementPtr parseString(const std::string& str,
ParserType parser_type);
/// @brief Run the parser on the file specified.
///
/// This method parses specified file. Depending on the value of
/// parser_type, parser may either check only that the input is valid
/// JSON, or may do more specific syntax checking. See @ref ParserType
/// for supported syntax checkers.
///
/// @param filename file to be parsed
/// @param parser_type specifies expected content (usually DHCP6 or generic JSON)
/// @return Element structure representing parsed text.
isc::data::ElementPtr parseFile(const std::string& filename,
ParserType parser_type);
/// @brief Error handler
///
/// @note The optional position for an error in a string begins by 1
/// so the caller should add 1 to the position of the C++ string.
///
/// @param loc location within the parsed file when experienced a problem.
/// @param what string explaining the nature of the error.
/// @param pos optional position for in string errors.
/// @throw Dhcp6ParseError
void error(const isc::dhcp::location& loc,
const std::string& what,
size_t pos = 0);
/// @brief Error handler
///
/// This is a simplified error reporting tool for possible future
/// cases when the Dhcp6Parser is not able to handle the packet.
///
/// @param what string explaining the nature of the error.
/// @throw Dhcp6ParseError
void error(const std::string& what);
/// @brief Fatal error handler
///
/// This is for should not happen but fatal errors.
/// Used by YY_FATAL_ERROR macro so required to be static.
///
/// @param what string explaining the nature of the error.
/// @throw Dhcp6ParseError
static void fatal(const std::string& what);
/// @brief Converts bison's position to one understandable by isc::data::Element
///
/// Convert a bison location into an element position
/// (take the begin, the end is lost)
///
/// @param loc location in bison format
/// @return Position in format accepted by Element
isc::data::Element::Position loc2pos(isc::dhcp::location& loc);
/// @brief Check if a required parameter is present
///
/// Check if a required parameter is present in the map at the top
/// of the stack and raise an error when it is not.
///
/// @param name name of the parameter expected to be present
/// @param open_loc location of the opening curly bracket
/// @param close_loc location of the closing curly bracket
/// @throw Dhcp6ParseError
void require(const std::string& name,
isc::data::Element::Position open_loc,
isc::data::Element::Position close_loc);
/// @brief Check if a parameter is already present
///
/// Check if a parameter is already present in the map at the top
/// of the stack and raise an error when it is.
///
/// @param name name of the parameter to check
/// @param loc location of the current parameter
/// @throw Dhcp6ParseError
void unique(const std::string& name,
isc::data::Element::Position loc);
/// @brief Defines syntactic contexts for lexical tie-ins
typedef enum {
///< This one is used in pure JSON mode.
NO_KEYWORD,
///< Used while parsing top level (that contains Dhcp6)
CONFIG,
///< Used while parsing content of Dhcp6.
DHCP6,
/// Used while parsing Dhcp6/interfaces structures.
INTERFACES_CONFIG,
/// Sanity checks.
SANITY_CHECKS,
/// Used while parsing Dhcp6/lease-database structures.
LEASE_DATABASE,
/// Used while parsing Dhcp6/hosts-database[s] structures.
HOSTS_DATABASE,
/// Used while parsing Dhcp6/*-database/type.
DATABASE_TYPE,
/// Used while parsing Dhcp6/*-database/on-fail.
DATABASE_ON_FAIL,
/// Used while parsing Dhcp6/mac-sources structures.
MAC_SOURCES,
/// Used while parsing Dhcp6/host-reservation-identifiers.
HOST_RESERVATION_IDENTIFIERS,
/// Used while parsing Dhcp6/hooks-libraries.
HOOKS_LIBRARIES,
/// Used while parsing Dhcp6/Subnet6 structures.
SUBNET6,
/// Used while parsing shared-networks structures.
SHARED_NETWORK,
/// Used while parsing Dhcp6/reservation-mode.
RESERVATION_MODE,
/// Used while parsing Dhcp6/option-def structures.
OPTION_DEF,
/// Used while parsing Dhcp6/option-data, Dhcp6/subnet6/option-data
/// or anywhere option-data is present (client classes, host
/// reservations and possibly others).
OPTION_DATA,
/// Used while parsing Dhcp6/client-classes structures.
CLIENT_CLASSES,
/// Used while parsing Dhcp6/expired-leases-processing.
EXPIRED_LEASES_PROCESSING,
/// Used while parsing Dhcp6/server-id structures.
SERVER_ID,
/// Used while parsing Dhcp6/server-id/type structures.
DUID_TYPE,
/// Used while parsing Dhcp6/control-socket structures.
CONTROL_SOCKET,
/// Used while parsing Dhcp6/dhcp-queue-control structures.
DHCP_QUEUE_CONTROL,
/// Used while parsing Dhcp6/multi-threading structures.
DHCP_MULTI_THREADING,
/// Used while parsing Dhcp6/subnet6/pools structures.
POOLS,
/// Used while parsing Dhcp6/subnet6/pd-pools structures.
PD_POOLS,
/// Used while parsing Dhcp6/reservations structures.
RESERVATIONS,
/// Used while parsing Dhcp6/subnet6/relay structures.
RELAY,
/// Used while parsing Dhcp6/loggers structures.
LOGGERS,
/// Used while parsing Dhcp6/loggers/output_options structures.
OUTPUT_OPTIONS,
/// Used while parsing Dhcp6/dhcp-ddns.
DHCP_DDNS,
/// Used while parsing Dhcp6/dhcp-ddns/ncr-protocol
NCR_PROTOCOL,
/// Used while parsing Dhcp6/dhcp-ddns/ncr-format
NCR_FORMAT,
/// Used while parsing Dhcp6/dhcp-ddns/replace-client-name.
REPLACE_CLIENT_NAME,
/// Used while parsing Dhcp6/config-control
CONFIG_CONTROL,
/// Used while parsing config-control/config-databases
CONFIG_DATABASE
} ParserContext;
/// @brief File name
std::string file_;
/// @brief File name stack
std::vector<std::string> files_;
/// @brief Location of the current token
///
/// The lexer will keep updating it. This variable will be useful
/// for logging errors.
isc::dhcp::location loc_;
/// @brief Location stack
std::vector<isc::dhcp::location> locs_;
/// @brief Lexer state stack
std::vector<struct yy_buffer_state*> states_;
/// @brief sFile (aka FILE)
FILE* sfile_;
/// @brief sFile (aka FILE) stack
///
/// This is a stack of files. Typically there's only one file (the
/// one being currently parsed), but there may be more if one
/// file includes another.
std::vector<FILE*> sfiles_;
/// @brief Current syntactic context
ParserContext ctx_;
/// @brief Enter a new syntactic context
///
/// Entering a new syntactic context is useful in several ways.
/// First, it allows the parser to avoid conflicts. Second, it
/// allows the lexer to return different tokens depending on
/// context (e.g. if "renew-timer" string is detected, the lexer
/// will return STRING token if in JSON mode or RENEW_TIMER if
/// in DHCP6 mode. Finally, the syntactic context allows the
/// error message to be more descriptive if the input string
/// does not parse properly.
///
/// @param ctx the syntactic context to enter into
void enter(const ParserContext& ctx);
/// @brief Leave a syntactic context
///
/// @throw isc::Unexpected if unbalanced
void leave();
/// @brief Get the syntactic context name
///
/// @return printable name of the context.
const std::string contextName();
private:
/// @brief Flag determining scanner debugging.
bool trace_scanning_;
/// @brief Flag determining parser debugging.
bool trace_parsing_;
/// @brief Syntactic context stack
std::vector<ParserContext> cstack_;
/// @brief Common part of parseXXX
///
/// @return Element structure representing parsed text.
isc::data::ElementPtr parseCommon();
};
}; // end of isc::eval namespace
}; // end of isc namespace
#endif