[2544] Added option config parser classes to DHCPv4.

src/bin/dhcp4/config_parser.cc

@@ -13,9 +13,12 @@
 // PERFORMANCE OF THIS SOFTWARE.
 
 #include <config/ccsession.h>
-#include <dhcpsrv/cfgmgr.h>
 #include <dhcp4/config_parser.h>
 #include <dhcp4/dhcp4_log.h>
+#include <dhcp/libdhcp++.h>
+#include <dhcp/option_definition.h>
+#include <dhcpsrv/cfgmgr.h>
+#include <util/encode/hex.h>
 #include <boost/foreach.hpp>
 #include <boost/lexical_cast.hpp>
 #include <boost/algorithm/string.hpp>
@@ -46,12 +49,20 @@ typedef std::map<std::string, ParserFactory*> FactoryMap;
 /// no subnet object created yet to store them.
 typedef std::vector<Pool4Ptr> PoolStorage;
 
+/// @brief Collection of option descriptors. This container allows searching for
+/// options using the option code or persistency flag. This is useful when merging
+/// existing options with newly configured options.
+typedef Subnet::OptionContainer OptionStorage;
+
 /// @brief Global uint32 parameters that will be used as defaults.
 Uint32Storage uint32_defaults;
 
 /// @brief global string parameters that will be used as defaults.
 StringStorage string_defaults;
 
+/// @brief Global storage for options that will be used as defaults.
+OptionStorage option_defaults;
+
 /// @brief a dummy configuration parser
 ///
 /// It is a debugging parser. It does not configure anything,
@@ -451,6 +462,344 @@ private:
     PoolStorage* pools_;
 };
 
+/// @brief Parser for option data value.
+///
+/// This parser parses configuration entries that specify value of
+/// a single option. These entries include option name, option code
+/// and data carried by the option. If parsing is successful than an
+/// instance of an option is created and added to the storage provided
+/// by the calling class.
+///
+/// @todo This class parses and validates the option name. However it is
+/// not used anywhere util support for option spaces is implemented
+/// (see tickets #2319, #2314). When option spaces are implemented
+/// there will be a way to reference the particular option using
+/// its type (code) or option name.
+class OptionDataParser : public Dhcp4ConfigParser {
+public:
+
+    /// @brief Constructor.
+    ///
+    /// Class constructor.
+    OptionDataParser(const std::string&)
+        : options_(NULL),
+          // initialize option to NULL ptr
+          option_descriptor_(false) { }
+
+    /// @brief Parses the single option data.
+    ///
+    /// This method parses the data of a single option from the configuration.
+    /// The option data includes option name, option code and data being
+    /// carried by this option. Eventually it creates the instance of the
+    /// option.
+    ///
+    /// @warning setStorage must be called with valid storage pointer prior
+    /// to calling this method.
+    ///
+    /// @param option_data_entries collection of entries that define value
+    /// for a particular option.
+    /// @throw Dhcp4ConfigError if invalid parameter specified in
+    /// the configuration.
+    /// @throw isc::InvalidOperation if failed to set storage prior to
+    /// calling build.
+    /// @throw isc::BadValue if option data storage is invalid.
+    virtual void build(ConstElementPtr option_data_entries) {
+        if (options_ == NULL) {
+            isc_throw(isc::InvalidOperation, "Parser logic error: storage must be set before "
+                      "parsing option data.");
+        }
+        BOOST_FOREACH(ConfigPair param, option_data_entries->mapValue()) {
+            ParserPtr parser;
+            if (param.first == "name") {
+                boost::shared_ptr<StringParser>
+                    name_parser(dynamic_cast<StringParser*>(StringParser::Factory(param.first)));
+                if (name_parser) {
+                    name_parser->setStorage(&string_values_);
+                    parser = name_parser;
+                }
+            } else if (param.first == "code") {
+                boost::shared_ptr<Uint32Parser>
+                    code_parser(dynamic_cast<Uint32Parser*>(Uint32Parser::Factory(param.first)));
+                if (code_parser) {
+                    code_parser->setStorage(&uint32_values_);
+                    parser = code_parser;
+                }
+            } else if (param.first == "data") {
+                boost::shared_ptr<StringParser>
+                    value_parser(dynamic_cast<StringParser*>(StringParser::Factory(param.first)));
+                if (value_parser) {
+                    value_parser->setStorage(&string_values_);
+                    parser = value_parser;
+                }
+            } else {
+                isc_throw(Dhcp4ConfigError,
+                          "Parser error: option-data parameter not supported: "
+                          << param.first);
+            }
+            parser->build(param.second);
+        }
+        // Try to create the option instance.
+        createOption();
+    }
+
+    /// @brief Commits option value.
+    ///
+    /// This function adds a new option to the storage or replaces an existing option
+    /// with the same code.
+    ///
+    /// @throw isc::InvalidOperation if failed to set pointer to storage or failed
+    /// to call build() prior to commit. If that happens data in the storage
+    /// remain un-modified.
+    virtual void commit() {
+        if (options_ == NULL) {
+            isc_throw(isc::InvalidOperation, "Parser logic error: storage must be set before "
+                      "commiting option data.");
+        } else  if (!option_descriptor_.option) {
+            // Before we can commit the new option should be configured. If it is not
+            // than somebody must have called commit() before build().
+            isc_throw(isc::InvalidOperation, "Parser logic error: no option has been configured and"
+                      " thus there is nothing to commit. Has build() been called?");
+        }
+        uint16_t opt_type = option_descriptor_.option->getType();
+        Subnet::OptionContainerTypeIndex& idx = options_->get<1>();
+        // Try to find options with the particular option code in the main
+        // storage. If found, remove these options because they will be
+        // replaced with new one.
+        Subnet::OptionContainerTypeRange range =
+            idx.equal_range(opt_type);
+        if (std::distance(range.first, range.second) > 0) {
+            idx.erase(range.first, range.second);
+        }
+        // Append new option to the main storage.
+        options_->push_back(option_descriptor_);
+    }
+
+    /// @brief Set storage for the parser.
+    ///
+    /// Sets storage for the parser. This storage points to the
+    /// vector of options and is used by multiple instances of
+    /// OptionDataParser. Each instance creates exactly one object
+    /// of dhcp::Option or derived type and appends it to this
+    /// storage.
+    ///
+    /// @param storage pointer to the options storage
+    void setStorage(OptionStorage* storage) {
+        options_ = storage;
+    }
+
+private:
+
+    /// @brief Create option instance.
+    ///
+    /// Creates an instance of an option and adds it to the provided
+    /// options storage. If the option data parsed by \ref build function
+    /// are invalid or insufficient this function emits an exception.
+    ///
+    /// @warning this function does not check if options_ storage pointer
+    /// is intitialized but this check is not needed here because it is done
+    /// in the \ref build function.
+    ///
+    /// @throw Dhcp4ConfigError if parameters provided in the configuration
+    /// are invalid.
+    void createOption() {
+        // Option code is held in the uint32_t storage but is supposed to
+        // be uint16_t value. We need to check that value in the configuration
+        // does not exceed range of uint16_t and is not zero.
+        uint32_t option_code = getUint32Param("code");
+        if (option_code == 0) {
+            isc_throw(Dhcp4ConfigError, "Parser error: value of 'code' must not"
+                      << " be equal to zero. Option code '0' is reserved in"
+                      << " DHCPv4.");
+        } else if (option_code > std::numeric_limits<uint16_t>::max()) {
+            isc_throw(Dhcp4ConfigError, "Parser error: value of 'code' must not"
+                      << " exceed " << std::numeric_limits<uint16_t>::max());
+        }
+        // Check that the option name has been specified, is non-empty and does not
+        // contain spaces.
+        // @todo possibly some more restrictions apply here?
+        std::string option_name = getStringParam("name");
+        if (option_name.empty()) {
+            isc_throw(Dhcp4ConfigError, "Parser error: option name must not be"
+                      << " empty");
+        } else if (option_name.find(" ") != std::string::npos) {
+            isc_throw(Dhcp4ConfigError, "Parser error: option name must not contain"
+                      << " spaces");
+        }
+
+        // Get option data from the configuration database ('data' field).
+        // Option data is specified by the user as case insensitive string
+        // of hexadecimal digits for each option.
+        std::string option_data = getStringParam("data");
+        // Transform string of hexadecimal digits into binary format.
+        std::vector<uint8_t> binary;
+        try {
+            util::encode::decodeHex(option_data, binary);
+        } catch (...) {
+            isc_throw(Dhcp4ConfigError, "Parser error: option data is not a valid"
+                      << " string of hexadecimal digits: " << option_data);
+        }
+        // Get all existing DHCPv4 option definitions. The one that matches
+        // our option will be picked and used to create it.
+        OptionDefContainer option_defs = LibDHCP::getOptionDefs(Option::V4);
+        // Get search index #1. It allows searching for options definitions
+        // using option type value.
+        const OptionDefContainerTypeIndex& idx = option_defs.get<1>();
+        // Get all option definitions matching option code we want to create.
+        const OptionDefContainerTypeRange& range = idx.equal_range(option_code);
+        size_t num_defs = std::distance(range.first, range.second);
+        OptionPtr option;
+        // Currently we do not allow duplicated definitions and if there are
+        // any duplicates we issue internal server error.
+        if (num_defs > 1) {
+            isc_throw(Dhcp4ConfigError, "Internal error: currently it is not"
+                      << " supported to initialize multiple option definitions"
+                      << " for the same option code. This will be supported once"
+                      << " there option spaces are implemented.");
+        } else if (num_defs == 0) {
+            // @todo We have a limited set of option definitions intiialized at the moment.
+            // In the future we want to initialize option definitions for all options.
+            // Consequently an error will be issued if an option definition does not exist
+            // for a particular option code. For now it is ok to create generic option
+            // if definition does not exist.
+            OptionPtr option(new Option(Option::V4, static_cast<uint16_t>(option_code),
+                                        binary));
+            // The created option is stored in option_descriptor_ class member until the
+            // commit stage when it is inserted into the main storage. If an option with the
+            // same code exists in main storage already the old option is replaced.
+            option_descriptor_.option = option;
+            option_descriptor_.persistent = false;
+        } else {
+            // We have exactly one option definition for the particular option code
+            // use it to create the option instance.
+            const OptionDefinitionPtr& def = *(range.first);
+            try {
+                OptionPtr option = def->optionFactory(Option::V4, option_code, binary);
+                Subnet::OptionDescriptor desc(option, false);
+                option_descriptor_.option = option;
+                option_descriptor_.persistent = false;
+            } catch (const isc::Exception& ex) {
+                isc_throw(Dhcp4ConfigError, "Parser error: option data does not match"
+                          << " option definition (code " << option_code << "): "
+                          << ex.what());
+            }
+        }
+    }
+
+    /// @brief Get a parameter from the strings storage.
+    ///
+    /// @param param_id parameter identifier.
+    /// @throw Dhcp4ConfigError if parameter has not been found.
+    std::string getStringParam(const std::string& param_id) const {
+        StringStorage::const_iterator param = string_values_.find(param_id);
+        if (param == string_values_.end()) {
+            isc_throw(Dhcp4ConfigError, "Parser error: option-data parameter"
+                      << " '" << param_id << "' not specified");
+        }
+        return (param->second);
+    }
+
+    /// @brief Get a parameter from the uint32 values storage.
+    ///
+    /// @param param_id parameter identifier.
+    /// @throw Dhcp4ConfigError if parameter has not been found.
+    uint32_t getUint32Param(const std::string& param_id) const {
+        Uint32Storage::const_iterator param = uint32_values_.find(param_id);
+        if (param == uint32_values_.end()) {
+            isc_throw(Dhcp4ConfigError, "Parser error: option-data parameter"
+                      << " '" << param_id << "' not specified");
+        }
+        return (param->second);
+    }
+
+    /// Storage for uint32 values (e.g. option code).
+    Uint32Storage uint32_values_;
+    /// Storage for string values (e.g. option name or data).
+    StringStorage string_values_;
+    /// Pointer to options storage. This storage is provided by
+    /// the calling class and is shared by all OptionDataParser objects.
+    OptionStorage* options_;
+    /// Option descriptor holds newly configured option.
+    Subnet::OptionDescriptor option_descriptor_;
+};
+
+/// @brief Parser for option data values within a subnet.
+///
+/// This parser iterates over all entries that define options
+/// data for a particular subnet and creates a collection of options.
+/// If parsing is successful, all these options are added to the Subnet
+/// object.
+class OptionDataListParser : public Dhcp4ConfigParser {
+public:
+
+    /// @brief Constructor.
+    ///
+    /// Unless otherwise specified, parsed options will be stored in
+    /// a global option container (option_default). That storage location
+    /// is overriden on a subnet basis.
+    OptionDataListParser(const std::string&)
+        : options_(&option_defaults), local_options_() { }
+
+    /// @brief Parses entries that define options' data for a subnet.
+    ///
+    /// This method iterates over all entries that define option data
+    /// for options within a single subnet and creates options' instances.
+    ///
+    /// @param option_data_list pointer to a list of options' data sets.
+    /// @throw Dhcp4ConfigError if option parsing failed.
+    void build(ConstElementPtr option_data_list) {
+        BOOST_FOREACH(ConstElementPtr option_value, option_data_list->listValue()) {
+            boost::shared_ptr<OptionDataParser> parser(new OptionDataParser("option-data"));
+            // options_ member will hold instances of all options thus
+            // each OptionDataParser takes it as a storage.
+            parser->setStorage(&local_options_);
+            // Build the instance of a single option.
+            parser->build(option_value);
+            // Store a parser as it will be used to commit.
+            parsers_.push_back(parser);
+        }
+    }
+
+    /// @brief Set storage for option instances.
+    ///
+    /// @param storage pointer to options storage.
+    void setStorage(OptionStorage* storage) {
+        options_ = storage;
+    }
+
+
+    /// @brief Commit all option values.
+    ///
+    /// This function invokes commit for all option values.
+    void commit() {
+        BOOST_FOREACH(ParserPtr parser, parsers_) {
+            parser->commit();
+        }
+        // Parsing was successful and we have all configured
+        // options in local storage. We can now replace old values
+        // with new values.
+        std::swap(local_options_, *options_);
+    }
+
+    /// @brief Create DhcpDataListParser object
+    ///
+    /// @param param_name param name.
+    ///
+    /// @return DhcpConfigParser object.
+    static Dhcp4ConfigParser* Factory(const std::string& param_name) {
+        return (new OptionDataListParser(param_name));
+    }
+
+    /// Intermediate option storage. This storage is used by
+    /// lower level parsers to add new options.  Values held
+    /// in this storage are assigned to main storage (options_)
+    /// if overall parsing was successful.
+    OptionStorage local_options_;
+    /// Pointer to options instances storage.
+    OptionStorage* options_;
+    /// Collection of parsers;
+    ParserCollection parsers_;
+};
+
 /// @brief this class parses a single subnet
 ///
 /// This class parses the whole subnet definition. It creates parsers