[2270] Configuration parser for DHCPv4

src/bin/dhcp4/Makefile.am

@@ -44,6 +44,7 @@ pkglibexec_PROGRAMS = b10-dhcp4
 
 b10_dhcp4_SOURCES  = main.cc
 b10_dhcp4_SOURCES += ctrl_dhcp4_srv.cc ctrl_dhcp4_srv.h
+b10_dhcp4_SOURCES += config_parser.cc config_parser.h
 b10_dhcp4_SOURCES += dhcp4_log.cc dhcp4_log.h
 b10_dhcp4_SOURCES += dhcp4_srv.cc dhcp4_srv.h
 
@@ -57,6 +58,7 @@ b10_dhcp4_CXXFLAGS = -Wno-unused-parameter
 endif
 
 b10_dhcp4_LDADD  = $(top_builddir)/src/lib/dhcp/libb10-dhcp++.la
+b10_dhcp4_LDADD += $(top_builddir)/src/lib/dhcp/libb10-dhcpsrv.la
 b10_dhcp4_LDADD += $(top_builddir)/src/lib/exceptions/libb10-exceptions.la
 b10_dhcp4_LDADD += $(top_builddir)/src/lib/asiolink/libb10-asiolink.la
 b10_dhcp4_LDADD += $(top_builddir)/src/lib/log/libb10-log.la

src/bin/dhcp4/config_parser.cc

@@ -0,0 +1,790 @@
+// Copyright (C) 2010  Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include <stdint.h>
+#include <iostream>
+#include <vector>
+#include <map>
+#include <boost/foreach.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/scoped_ptr.hpp>
+#include <boost/lexical_cast.hpp>
+#include <boost/algorithm/string.hpp>
+#include <asiolink/io_address.h>
+#include <cc/data.h>
+#include <config/ccsession.h>
+#include <log/logger_support.h>
+#include <dhcp/triplet.h>
+#include <dhcp/pool.h>
+#include <dhcp/subnet.h>
+#include <dhcp/cfgmgr.h>
+#include <dhcp4/config_parser.h>
+#include <dhcp4/dhcp4_log.h>
+
+using namespace std;
+using namespace isc::data;
+using namespace isc::asiolink;
+
+namespace isc {
+namespace dhcp {
+
+/// @brief auxiliary type used for storing element name and its parser
+typedef pair<string, ConstElementPtr> ConfigPair;
+
+/// @brief a factory method that will create a parser for a given element name
+typedef DhcpConfigParser* ParserFactory(const std::string& config_id);
+
+/// @brief a collection of factories that creates parsers for specified element names
+typedef std::map<std::string, ParserFactory*> FactoryMap;
+
+/// @brief a collection of elements that store uint32 values (e.g. renew-timer = 900)
+typedef std::map<string, uint32_t> Uint32Storage;
+
+/// @brief a collection of elements that store string values
+typedef std::map<string, string> StringStorage;
+
+/// @brief a collection of pools
+///
+/// That type is used as intermediate storage, when pools are parsed, but there is
+/// no subnet object created yet to store them.
+typedef std::vector<Pool4Ptr> PoolStorage;
+
+/// @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 a dummy configuration parser
+///
+/// It is a debugging parser. It does not configure anything,
+/// will accept any configuration and will just print it out
+/// on commit. Useful for debugging existing configurations and
+/// adding new ones.
+class DebugParser : public DhcpConfigParser {
+public:
+
+    /// @brief Constructor
+    ///
+    /// See \ref DhcpConfigParser class for details.
+    ///
+    /// @param param_name name of the parsed parameter
+    DebugParser(const std::string& param_name)
+        :param_name_(param_name) {
+    }
+
+    /// @brief builds parameter value
+    ///
+    /// See \ref DhcpConfigParser class for details.
+    ///
+    /// @param new_config pointer to the new configuration
+    virtual void build(ConstElementPtr new_config) {
+        std::cout << "Build for token: [" << param_name_ << "] = ["
+                  << value_->str() << "]" << std::endl;
+        value_ = new_config;
+    }
+
+    /// @brief pretends to apply the configuration
+    ///
+    /// This is a method required by base class. It pretends to apply the
+    /// configuration, but in fact it only prints the parameter out.
+    ///
+    /// See \ref DhcpConfigParser class for details.
+    virtual void commit() {
+        // Debug message. The whole DebugParser class is used only for parser
+        // debugging, and is not used in production code. It is very convenient
+        // to keep it around. Please do not turn this cout into logger calls.
+        std::cout << "Commit for token: [" << param_name_ << "] = ["
+                  << value_->str() << "]" << std::endl;
+    }
+
+    /// @brief factory that constructs DebugParser objects
+    ///
+    /// @param param_name name of the parameter to be parsed
+    static DhcpConfigParser* Factory(const std::string& param_name) {
+        return (new DebugParser(param_name));
+    }
+
+protected:
+    /// name of the parsed parameter
+    std::string param_name_;
+
+    /// pointer to the actual value of the parameter
+    ConstElementPtr value_;
+};
+
+/// @brief Configuration parser for uint32 parameters
+///
+/// This class is a generic parser that is able to handle any uint32 integer
+/// type. By default it stores the value in external global container
+/// (uint32_defaults). If used in smaller scopes (e.g. to parse parameters
+/// in subnet config), it can be pointed to a different storage, using
+/// setStorage() method. This class follows the parser interface, laid out
+/// in its base class, \ref DhcpConfigParser.
+///
+/// For overview of usability of this generic purpose parser, see
+/// \ref dhcpv4-config-inherit page.
+class Uint32Parser : public DhcpConfigParser {
+public:
+
+    /// @brief constructor for Uint32Parser
+    /// @param param_name name of the configuration parameter being parsed
+    Uint32Parser(const std::string& param_name)
+        :storage_(&uint32_defaults), param_name_(param_name) {
+    }
+
+    /// @brief builds parameter value
+    ///
+    /// Parses configuration entry and stores it in a storage. See
+    /// \ref setStorage() for details.
+    ///
+    /// @param value pointer to the content of parsed values
+    virtual void build(ConstElementPtr value) {
+        try {
+            value_ = boost::lexical_cast<uint32_t>(value->str());
+        } catch (const boost::bad_lexical_cast &) {
+            isc_throw(BadValue, "Failed to parse value " << value->str()
+                      << " as unsigned 32-bit integer.");
+        }
+        storage_->insert(pair<string, uint32_t>(param_name_, value_));
+    }
+
+    /// @brief does nothing
+    ///
+    /// This method is required for all parser. The value itself
+    /// is not commited anywhere. Higher level parsers are expected to
+    /// use values stored in the storage, e.g. renew-timer for a given
+    /// subnet is stored in subnet-specific storage. It is not commited
+    /// here, but is rather used by \ref Subnet4Parser when constructing
+    /// the subnet.
+    virtual void commit() {
+    }
+
+    /// @brief factory that constructs Uint32Parser objects
+    ///
+    /// @param param_name name of the parameter to be parsed
+    static DhcpConfigParser* Factory(const std::string& param_name) {
+        return (new Uint32Parser(param_name));
+    }
+
+    /// @brief sets storage for value of this parameter
+    ///
+    /// See \ref dhcpv4-config-inherit for details.
+    ///
+    /// @param storage pointer to the storage container
+    void setStorage(Uint32Storage* storage) {
+        storage_ = storage;
+    }
+
+protected:
+    /// pointer to the storage, where parsed value will be stored
+    Uint32Storage* storage_;
+
+    /// name of the parameter to be parsed
+    std::string param_name_;
+
+    /// the actual parsed value
+    uint32_t value_;
+};
+
+/// @brief Configuration parser for string parameters
+///
+/// This class is a generic parser that is able to handle any string
+/// parameter. By default it stores the value in external global container
+/// (string_defaults). If used in smaller scopes (e.g. to parse parameters
+/// in subnet config), it can be pointed to a different storage, using
+/// setStorage() method. This class follows the parser interface, laid out
+/// in its base class, \ref DhcpConfigParser.
+///
+/// For overview of usability of this generic purpose parser, see
+/// \ref dhcpv4-config-inherit page.
+class StringParser : public DhcpConfigParser {
+public:
+
+    /// @brief constructor for StringParser
+    /// @param param_name name of the configuration parameter being parsed
+    StringParser(const std::string& param_name)
+        :storage_(&string_defaults), param_name_(param_name) {
+    }
+
+    /// @brief parses parameter value
+    ///
+    /// Parses configuration entry and stored it in storage. See
+    /// \ref setStorage() for details.
+    ///
+    /// @param value pointer to the content of parsed values
+    virtual void build(ConstElementPtr value) {
+        value_ = value->str();
+        boost::erase_all(value_, "\"");
+        storage_->insert(pair<string, string>(param_name_, value_));
+    }
+
+    /// @brief does nothing
+    ///
+    /// This method is required for all parser. The value itself
+    /// is not commited anywhere. Higher level parsers are expected to
+    /// use values stored in the storage, e.g. renew-timer for a given
+    /// subnet is stored in subnet-specific storage. It is not commited
+    /// here, but is rather used by its parent parser when constructing
+    /// an object, e.g. the subnet.
+    virtual void commit() {
+    }
+
+    /// @brief factory that constructs StringParser objects
+    ///
+    /// @param param_name name of the parameter to be parsed
+    static DhcpConfigParser* Factory(const std::string& param_name) {
+        return (new StringParser(param_name));
+    }
+
+    /// @brief sets storage for value of this parameter
+    ///
+    /// See \ref dhcpv4-config-inherit for details.
+    ///
+    /// @param storage pointer to the storage container
+    void setStorage(StringStorage* storage) {
+        storage_ = storage;
+    }
+
+protected:
+    /// pointer to the storage, where parsed value will be stored
+    StringStorage* storage_;
+
+    /// name of the parameter to be parsed
+    std::string param_name_;
+
+    /// the actual parsed value
+    std::string value_;
+};
+
+
+/// @brief parser for interface list definition
+///
+/// This parser handles Dhcp4/interface entry.
+/// It contains a list of network interfaces that the server listens on.
+/// In particular, it can contain an entry called "all" or "any" that
+/// designates all interfaces.
+///
+/// It is useful for parsing Dhcp4/interface parameter.
+class InterfaceListConfigParser : public DhcpConfigParser {
+public:
+
+    /// @brief constructor
+    ///
+    /// As this is a dedicated parser, it must be used to parse
+    /// "interface" parameter only. All other types will throw exception.
+    ///
+    /// @param param_name name of the configuration parameter being parsed
+    InterfaceListConfigParser(const std::string& param_name) {
+        if (param_name != "interface") {
+            isc_throw(NotImplemented, "Internal error. Interface configuration "
+                      "parser called for the wrong parameter: " << param_name);
+        }
+    }
+
+    /// @brief parses parameters value
+    ///
+    /// Parses configuration entry (list of parameters) and stores it in
+    /// storage. See \ref setStorage() for details.
+    ///
+    /// @param value pointer to the content of parsed values
+    virtual void build(ConstElementPtr value) {
+        BOOST_FOREACH(ConstElementPtr iface, value->listValue()) {
+            interfaces_.push_back(iface->str());
+        }
+    }
+
+    /// @brief commits interfaces list configuration
+    virtual void commit() {
+        /// @todo: Implement per interface listening. Currently always listening
+        /// on all interfaces.
+    }
+
+    /// @brief factory that constructs InterfaceListConfigParser objects
+    ///
+    /// @param param_name name of the parameter to be parsed
+    static DhcpConfigParser* Factory(const std::string& param_name) {
+        return (new InterfaceListConfigParser(param_name));
+    }
+
+protected:
+    /// contains list of network interfaces
+    vector<string> interfaces_;
+};
+
+/// @brief parser for pool definition
+///
+/// This parser handles pool definitions, i.e. a list of entries of one
+/// of two syntaxes: min-max and prefix/len. Pool4 objects are created
+/// and stored in chosen PoolStorage container.
+///
+/// As there are no default values for pool, setStorage() must be called
+/// before build(). Otherwise exception will be thrown.
+///
+/// It is useful for parsing Dhcp4/subnet4[X]/pool parameters.
+class PoolParser : public DhcpConfigParser {
+public:
+
+    /// @brief constructor.
+    PoolParser(const std::string& /*param_name*/)
+        :pools_(NULL) {
+        // ignore parameter name, it is always Dhcp4/subnet4[X]/pool
+    }
+
+    /// @brief parses the actual list
+    ///
+    /// This method parses the actual list of interfaces.
+    /// No validation is done at this stage, everything is interpreted as
+    /// interface name.
+    void build(ConstElementPtr pools_list) {
+        // setStorage() should have been called before build
+        if (!pools_) {
+            isc_throw(NotImplemented, "Parser logic error. No pool storage set,"
+                      " but pool parser asked to parse pools");
+        }
+
+        BOOST_FOREACH(ConstElementPtr text_pool, pools_list->listValue()) {
+
+            // That should be a single pool representation. It should contain
+            // text is form prefix/len or first - last. Note that spaces
+            // are allowed
+            string txt = text_pool->stringValue();
+
+            // first let's remove any whitespaces
+            boost::erase_all(txt, " "); // space
+            boost::erase_all(txt, "\t"); // tabulation
+
+            // Is this prefix/len notation?
+            size_t pos = txt.find("/");
+            if (pos != string::npos) {
+                IOAddress addr("::");
+                uint8_t len = 0;
+                try {
+                    addr = IOAddress(txt.substr(0, pos));
+
+                    // start with the first character after /
+                    string prefix_len = txt.substr(pos + 1);
+
+                    // It is lexical cast to int and then downcast to uint8_t.
+                    // Direct cast to uint8_t (which is really an unsigned char)
+                    // will result in interpreting the first digit as output
+                    // value and throwing exception if length is written on two
+                    // digits (because there are extra characters left over).
+
+                    // No checks for values over 128. Range correctness will
+                    // be checked in Pool4 constructor.
+                    len = boost::lexical_cast<int>(prefix_len);
+                } catch (...)  {
+                    isc_throw(Dhcp4ConfigError, "Failed to parse pool "
+                              "definition: " << text_pool->stringValue());
+                }
+
+                Pool4Ptr pool(new Pool4(addr, len));
+                pools_->push_back(pool);
+                continue;
+            }
+
+            // Is this min-max notation?
+            pos = txt.find("-");
+            if (pos != string::npos) {
+                // using min-max notation
+                IOAddress min(txt.substr(0,pos - 1));
+                IOAddress max(txt.substr(pos + 1));
+
+                Pool4Ptr pool(new Pool4(min, max));
+
+                pools_->push_back(pool);
+                continue;
+            }
+
+            isc_throw(Dhcp4ConfigError, "Failed to parse pool definition:"
+                      << text_pool->stringValue() <<
+                      ". Does not contain - (for min-max) nor / (prefix/len)");
+        }
+    }
+
+    /// @brief sets storage for value of this parameter
+    ///
+    /// See \ref dhcpv4-config-inherit for details.
+    ///
+    /// @param storage pointer to the storage container
+    void setStorage(PoolStorage* storage) {
+        pools_ = storage;
+    }
+
+    /// @brief does nothing.
+    ///
+    /// This method is required for all parser. The value itself
+    /// is not commited anywhere. Higher level parsers (for subnet) are expected
+    /// to use values stored in the storage.
+    virtual void commit() {}
+
+    /// @brief factory that constructs PoolParser objects
+    ///
+    /// @param param_name name of the parameter to be parsed
+    static DhcpConfigParser* Factory(const std::string& param_name) {
+        return (new PoolParser(param_name));
+    }
+
+protected:
+    /// @brief pointer to the actual Pools storage
+    ///
+    /// That is typically a storage somewhere in Subnet parser
+    /// (an upper level parser).
+    PoolStorage* pools_;
+};
+
+/// @brief this class parses a single subnet
+///
+/// This class parses the whole subnet definition. It creates parsers
+/// for received configuration parameters as needed.
+class Subnet4ConfigParser : public DhcpConfigParser {
+public:
+
+    /// @brief constructor
+    Subnet4ConfigParser(const std::string& ) {
+        // The parameter should always be "subnet", but we don't check here
+        // against it in case some wants to reuse this parser somewhere.
+    }
+
+    /// @brief parses parameter value
+    ///
+    /// @param subnet pointer to the content of subnet definition
+    void build(ConstElementPtr subnet) {
+
+        BOOST_FOREACH(ConfigPair param, subnet->mapValue()) {
+
+            ParserPtr parser(createSubnet4ConfigParser(param.first));
+
+            // if this is an Uint32 parser, tell it to store the values
+            // in values_, rather than in global storage
+            boost::shared_ptr<Uint32Parser> uintParser =
+                boost::dynamic_pointer_cast<Uint32Parser>(parser);
+            if (uintParser) {
+                uintParser->setStorage(&uint32_values_);
+            } else {
+
+                boost::shared_ptr<StringParser> stringParser =
+                    boost::dynamic_pointer_cast<StringParser>(parser);
+                if (stringParser) {
+                    stringParser->setStorage(&string_values_);
+                } else {
+
+                    boost::shared_ptr<PoolParser> poolParser =
+                        boost::dynamic_pointer_cast<PoolParser>(parser);
+                    if (poolParser) {
+                        poolParser->setStorage(&pools_);
+                    }
+                }
+            }
+
+            parser->build(param.second);
+            parsers_.push_back(parser);
+        }
+
+        // Ok, we now have subnet parsed
+    }
+
+    /// @brief commits received configuration.
+    ///
+    /// This method does most of the configuration. Many other parsers are just
+    /// storing the values that are actually consumed here. Pool definitions
+    /// created in other parsers are used here and added to newly created Subnet4
+    /// objects. Subnet4 are then added to DHCP CfgMgr.
+    void commit() {
+
+        StringStorage::const_iterator it = string_values_.find("subnet");
+        if (it == string_values_.end()) {
+            isc_throw(Dhcp4ConfigError,
+                      "Mandatory subnet definition in subnet missing");
+        }
+        string subnet_txt = it->second;
+        boost::erase_all(subnet_txt, " ");
+        boost::erase_all(subnet_txt, "\t");
+
+        size_t pos = subnet_txt.find("/");
+        if (pos == string::npos) {
+            isc_throw(Dhcp4ConfigError,
+                      "Invalid subnet syntax (prefix/len expected):" << it->second);
+        }
+        IOAddress addr(subnet_txt.substr(0, pos));
+        uint8_t len = boost::lexical_cast<unsigned int>(subnet_txt.substr(pos + 1));
+
+        Triplet<uint32_t> t1 = getParam("renew-timer");
+        Triplet<uint32_t> t2 = getParam("rebind-timer");
+        Triplet<uint32_t> valid = getParam("valid-lifetime");
+
+        /// @todo: Convert this to logger once the parser is working reliably
+        stringstream tmp;
+        tmp << addr.toText() << "/" << (int)len
+            << " with params t1=" << t1 << ", t2=" << t2 << ", valid=" << valid;
+
+        LOG_INFO(dhcp4_logger, DHCP4_CONFIG_NEW_SUBNET).arg(tmp.str());
+
+        Subnet4Ptr subnet(new Subnet4(addr, len, t1, t2, valid));
+
+        for (PoolStorage::iterator it = pools_.begin(); it != pools_.end(); ++it) {
+            subnet->addPool4(*it);
+        }
+
+        CfgMgr::instance().addSubnet4(subnet);
+    }
+
+protected:
+
+    /// @brief creates parsers for entries in subnet definition
+    ///
+    /// @todo Add subnet-specific things here (e.g. subnet-specific options)
+    ///
+    /// @param config_id name od the entry
+    /// @return parser object for specified entry name
+    DhcpConfigParser* createSubnet4ConfigParser(const std::string& config_id) {
+        FactoryMap factories;
+
+        factories.insert(pair<string, ParserFactory*>(
+                             "valid-lifetime", Uint32Parser::Factory));
+        factories.insert(pair<string, ParserFactory*>(
+                             "renew-timer", Uint32Parser::Factory));
+        factories.insert(pair<string, ParserFactory*>(
+                             "rebind-timer", Uint32Parser::Factory));
+
+        factories.insert(pair<string, ParserFactory*>(
+                             "subnet", StringParser::Factory));
+
+        factories.insert(pair<string, ParserFactory*>(
+                             "pool", PoolParser::Factory));
+
+        FactoryMap::iterator f = factories.find(config_id);
+        if (f == factories.end()) {
+            // Used for debugging only.
+            // return new DebugParser(config_id);
+
+            isc_throw(NotImplemented,
+                      "Parser error: Subnet4 parameter not supported: "
+                      << config_id);
+        }
+        return (f->second(config_id));
+    }
+
+    /// @brief returns value for a given parameter (after using inheritance)
+    ///
+    /// This method implements inheritance. For a given parameter name, it first
+    /// checks if there is a global value for it and overwrites it with specific
+    /// value if such value was defined in subnet.
+    ///
+    /// @param name name of the parameter
+    /// @return triplet with the parameter name
+    Triplet<uint32_t> getParam(const std::string& name) {
+        uint32_t value = 0;
+        bool found = false;
+        Uint32Storage::iterator global = uint32_defaults.find(name);
+        if (global != uint32_defaults.end()) {
+            value = global->second;
+            found = true;
+        }
+
+        Uint32Storage::iterator local = uint32_values_.find(name);
+        if (local != uint32_values_.end()) {
+            value = local->second;
+            found = true;
+        }
+
+        if (found) {
+            return (Triplet<uint32_t>(value));
+        } else {
+            isc_throw(Dhcp4ConfigError, "Mandatory parameter " << name
+                      << " missing (no global default and no subnet-"
+                      << "specific value)");
+        }
+    }
+
+    /// storage for subnet-specific uint32 values
+    Uint32Storage uint32_values_;
+
+    /// storage for subnet-specific integer values
+    StringStorage string_values_;
+
+    /// storage for pools belonging to this subnet
+    PoolStorage pools_;
+
+    /// parsers are stored here
+    ParserCollection parsers_;
+};
+
+/// @brief this class parses list of subnets
+///
+/// This is a wrapper parser that handles the whole list of Subnet4
+/// definitions. It iterates over all entries and creates Subnet4ConfigParser
+/// for each entry.
+class Subnets4ListConfigParser : public DhcpConfigParser {
+public:
+
+    /// @brief constructor
+    ///
+    Subnets4ListConfigParser(const std::string&) {
+        /// parameter name is ignored
+    }
+
+    /// @brief parses contents of the list
+    ///
+    /// Iterates over all entries on the list and creates Subnet4ConfigParser
+    /// for each entry.
+    ///
+    /// @param subnets_list pointer to a list of IPv4 subnets
+    void build(ConstElementPtr subnets_list) {
+
+        // No need to define FactoryMap here. There's only one type
+        // used: Subnet4ConfigParser
+
+        BOOST_FOREACH(ConstElementPtr subnet, subnets_list->listValue()) {
+
+            ParserPtr parser(new Subnet4ConfigParser("subnet"));
+            parser->build(subnet);
+            subnets_.push_back(parser);
+        }
+
+    }
+
+    /// @brief commits subnets definitions.
+    ///
+    /// Iterates over all Subnet4 parsers. Each parser contains definitions
+    /// of a single subnet and its parameters and commits each subnet separately.
+    void commit() {
+        // @todo: Implement more subtle reconfiguration than toss
+        // the old one and replace with the new one.
+
+        // remove old subnets
+        CfgMgr::instance().deleteSubnets4();
+
+        BOOST_FOREACH(ParserPtr subnet, subnets_) {
+            subnet->commit();
+        }
+
+    }
+
+    /// @brief Returns Subnet4ListConfigParser object
+    /// @param param_name name of the parameter
+    /// @return Subnets4ListConfigParser object
+    static DhcpConfigParser* Factory(const std::string& param_name) {
+        return (new Subnets4ListConfigParser(param_name));
+    }
+
+    /// @brief collection of subnet parsers.
+    ParserCollection subnets_;
+};
+
+/// @brief creates global parsers
+///
+/// This method creates global parsers that parse global parameters, i.e.
+/// those that take format of Dhcp4/param1, Dhcp4/param2 and so forth.
+///
+/// @param config_id pointer to received global configuration entry
+/// @return parser for specified global DHCPv4 parameter
+DhcpConfigParser* createGlobalDhcpConfigParser(const std::string& config_id) {
+    FactoryMap factories;
+
+    factories.insert(pair<string, ParserFactory*>(
+                         "valid-lifetime", Uint32Parser::Factory));
+    factories.insert(pair<string, ParserFactory*>(
+                         "renew-timer", Uint32Parser::Factory));
+    factories.insert(pair<string, ParserFactory*>(
+                         "rebind-timer", Uint32Parser::Factory));
+
+    factories.insert(pair<string, ParserFactory*>(
+                         "interface", InterfaceListConfigParser::Factory));
+    factories.insert(pair<string, ParserFactory*>(
+                         "subnet4", Subnets4ListConfigParser::Factory));
+
+    factories.insert(pair<string, ParserFactory*>(
+                         "version", StringParser::Factory));
+
+    FactoryMap::iterator f = factories.find(config_id);
+    if (f == factories.end()) {
+        // Used for debugging only.
+        // return new DebugParser(config_id);
+
+        isc_throw(NotImplemented,
+                  "Parser error: Global configuration parameter not supported: "
+                  << config_id);
+    }
+    return (f->second(config_id));
+}
+
+/// @brief configures DHCPv4 server
+///
+/// This function is called every time a new configuration is received. The extra
+/// parameter is a reference to DHCPv4 server component. It is currently not used
+/// and CfgMgr::instance() is accessed instead.
+///
+/// This method does not throw. It catches all exceptions and returns them as
+/// reconfiguration statuses. It may return the following response codes:
+/// 0 - configuration successful
+/// 1 - malformed configuration (parsing failed)
+/// 2 - logical error (parsing was successful, but the values are invalid)
+///
+/// @param config_set a new configuration for DHCPv4 server
+/// @return answer that contains result of reconfiguration
+isc::data::ConstElementPtr
+configureDhcp4Server(Dhcpv4Srv& , ConstElementPtr config_set) {
+    if (!config_set) {
+        isc_throw(Dhcp4ConfigError,
+                  "Null pointer is passed to configuration parser");
+    }
+
+    /// @todo: append most essential info here (like "2 new subnets configured")
+    string config_details;
+
+    LOG_DEBUG(dhcp4_logger, DBG_DHCP4_COMMAND, DHCP4_CONFIG_START).arg(config_set->str());
+
+    ParserCollection parsers;
+    try {
+        BOOST_FOREACH(ConfigPair config_pair, config_set->mapValue()) {
+
+            ParserPtr parser(createGlobalDhcpConfigParser(config_pair.first));
+            parser->build(config_pair.second);
+            parsers.push_back(parser);
+        }
+    } catch (const isc::Exception& ex) {
+        ConstElementPtr answer = isc::config::createAnswer(1,
+                                 string("Configuration parsing failed:") + ex.what());
+        return (answer);
+    } catch (...) {
+        // for things like bad_cast in boost::lexical_cast
+        ConstElementPtr answer = isc::config::createAnswer(1,
+                                 string("Configuration parsing failed"));
+    }
+
+    try {
+        BOOST_FOREACH(ParserPtr parser, parsers) {
+            parser->commit();
+        }
+    }
+    catch (const isc::Exception& ex) {
+        ConstElementPtr answer = isc::config::createAnswer(2,
+                                 string("Configuration commit failed:") + ex.what());
+        return (answer);
+    } catch (...) {
+        // for things like bad_cast in boost::lexical_cast
+        ConstElementPtr answer = isc::config::createAnswer(2,
+                                 string("Configuration commit failed"));
+    }
+
+    LOG_INFO(dhcp4_logger, DHCP4_CONFIG_COMPLETE).arg(config_details);
+
+    ConstElementPtr answer = isc::config::createAnswer(0, "Configuration commited.");
+    return (answer);
+}
+
+}; // end of isc::dhcp namespace
+}; // end of isc namespace

src/bin/dhcp4/config_parser.h

@@ -0,0 +1,147 @@
+// Copyright (C) 2012  Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include <string>
+#include <exceptions/exceptions.h>
+#include <cc/data.h>
+
+#ifndef DHCP4_CONFIG_PARSER_H
+#define DHCP4_CONFIG_PARSER_H
+
+namespace isc {
+namespace dhcp {
+
+class Dhcpv4Srv;
+
+/// An exception that is thrown if an error occurs while configuring an
+/// \c Dhcpv4Srv object.
+class Dhcp4ConfigError : public isc::Exception {
+public:
+
+/// @brief constructor
+///
+/// @param file name of the file, where exception occurred
+/// @param line line of the file, where exception occurred
+/// @param what text description of the issue that caused exception
+Dhcp4ConfigError(const char* file, size_t line, const char* what) :
+    isc::Exception(file, line, what) {}
+};
+
+class DhcpConfigParser {
+    ///
+    /// \name Constructors and Destructor
+    ///
+    /// Note: The copy constructor and the assignment operator are
+    /// intentionally defined as private to make it explicit that this is a
+    /// pure base class.
+    //@{
+private:
+    DhcpConfigParser(const DhcpConfigParser& source);
+    DhcpConfigParser& operator=(const DhcpConfigParser& source);
+protected:
+    /// \brief The default constructor.
+    ///
+    /// This is intentionally defined as \c protected as this base class should
+    /// never be instantiated (except as part of a derived class).
+    DhcpConfigParser() {}
+public:
+    /// The destructor.
+    virtual ~DhcpConfigParser() {}
+    //@}
+
+    /// \brief Prepare configuration value.
+    ///
+    /// This method parses the "value part" of the configuration identifier
+    /// that corresponds to this derived class and prepares a new value to
+    /// apply to the server.
+    ///
+    /// This method must validate the given value both in terms of syntax
+    /// and semantics of the configuration, so that the server will be
+    /// validly configured at the time of \c commit().  Note: the given
+    /// configuration value is normally syntactically validated, but the
+    /// \c build() implementation must also expect invalid input.  If it
+    /// detects an error it may throw an exception of a derived class
+    /// of \c isc::Exception.
+    ///
+    /// Preparing a configuration value will often require resource
+    /// allocation.  If it fails, it may throw a corresponding standard
+    /// exception.
+    ///
+    /// This method is not expected to be called more than once in the
+    /// life of the object. Although multiple calls are not prohibited
+    /// by the interface, the behavior is undefined.
+    ///
+    /// \param config_value The configuration value for the identifier
+    /// corresponding to the derived class.
+    virtual void build(isc::data::ConstElementPtr config_value) = 0;
+
+    /// \brief Apply the prepared configuration value to the server.
+    ///
+    /// This method is expected to be exception free, and, as a consequence,
+    /// it should normally not involve resource allocation.
+    /// Typically it would simply perform exception free assignment or swap
+    /// operation on the value prepared in \c build().
+    /// In some cases, however, it may be very difficult to meet this
+    /// condition in a realistic way, while the failure case should really
+    /// be very rare.  In such a case it may throw, and, if the parser is
+    /// called via \c configureDhcp4Server(), the caller will convert the
+    /// exception as a fatal error.
+    ///
+    /// This method is expected to be called after \c build(), and only once.
+    /// The result is undefined otherwise.
+    virtual void commit() = 0;
+};
+
+/// @brief a pointer to configuration parser
+typedef boost::shared_ptr<DhcpConfigParser> ParserPtr;
+
+/// @brief a collection of parsers
+///
+/// This container is used to store pointer to parsers for a given scope.
+typedef std::vector<ParserPtr> ParserCollection;
+
+
+/// \brief Configure an \c Dhcpv4Srv object with a set of configuration values.
+///
+/// This function parses configuration information stored in \c config_set
+/// and configures the \c server by applying the configuration to it.
+/// It provides the strong exception guarantee as long as the underlying
+/// derived class implementations of \c DhcpConfigParser meet the assumption,
+/// that is, it ensures that either configuration is fully applied or the
+/// state of the server is intact.
+///
+/// If a syntax or semantics level error happens during the configuration
+/// (such as malformed configuration or invalid configuration parameter),
+/// this function throws an exception of class \c Dhcp4ConfigError.
+/// If the given configuration requires resource allocation and it fails,
+/// a corresponding standard exception will be thrown.
+/// Other exceptions may also be thrown, depending on the implementation of
+/// the underlying derived class of \c Dhcp4ConfigError.
+/// In any case the strong guarantee is provided as described above except
+/// in the very rare cases where the \c commit() method of a parser throws
+/// an exception.  If that happens this function converts the exception
+/// into a \c FatalError exception and rethrows it.  This exception is
+/// expected to be caught at the highest level of the application to terminate
+/// the program gracefully.
+///
+/// \param server The \c Dhcpv4Srv object to be configured.
+/// \param config_set A JSON style configuration to apply to \c server.
+isc::data::ConstElementPtr
+configureDhcp4Server(Dhcpv4Srv& server,
+                     isc::data::ConstElementPtr config_set);
+
+}; // end of isc::dhcp namespace
+}; // end of isc namespace
+
+#endif // DHCP4_CONFIG_PARSER_H

src/bin/dhcp4/ctrl_dhcp4_srv.cc

@@ -25,6 +25,7 @@
 #include <dhcp4/ctrl_dhcp4_srv.h>
 #include <dhcp4/dhcp4_log.h>
 #include <dhcp4/spec_config.h>
+#include <dhcp4/config_parser.h>
 #include <dhcp/iface_mgr.h>
 #include <exceptions/exceptions.h>
 #include <util/buffer.h>
@@ -47,8 +48,14 @@ ConstElementPtr
 ControlledDhcpv4Srv::dhcp4ConfigHandler(ConstElementPtr new_config) {
     LOG_DEBUG(dhcp4_logger, DBG_DHCP4_COMMAND, DHCP4_CONFIG_UPDATE)
               .arg(new_config->str());
-    ConstElementPtr answer = isc::config::createAnswer(0,
-                             "Thank you for sending config.");
+    if (server_) {
+        return (configureDhcp4Server(*server_, new_config));
+    }
+
+    // That should never happen as we install config_handler after we instantiate
+    // the server.
+    ConstElementPtr answer = isc::config::createAnswer(1,
+           "Configuration rejected, server is during startup/shutdown phase.");
     return (answer);
 }
 
@@ -101,10 +108,22 @@ void ControlledDhcpv4Srv::establishSession() {
               .arg(specfile);
     cc_session_ = new Session(io_service_.get_io_service());
     config_session_ = new ModuleCCSession(specfile, *cc_session_,
-                                          dhcp4ConfigHandler,
+                                          NULL,
                                           dhcp4CommandHandler, false);
     config_session_->start();
 
+    // We initially create ModuleCCSession() without configHandler, as
+    // the session module is too eager to send partial configuration.
+    // We want to get the full configuration, so we explicitly call
+    // getFullConfig() and then pass it to our configHandler.
+    config_session_->setConfigHandler(dhcp4ConfigHandler);
+
+    try {
+        configureDhcp4Server(*this, config_session_->getFullConfig());
+    } catch (const Dhcp4ConfigError& ex) {
+        LOG_ERROR(dhcp4_logger, DHCP4_CONFIG_LOAD_FAIL).arg(ex.what());
+    }
+
     /// Integrate the asynchronous I/O model of BIND 10 configuration
     /// control with the "select" model of the DHCP server.  This is
     /// fully explained in \ref dhcpv4Session.

src/bin/dhcp4/dhcp4.spec

@@ -4,9 +4,85 @@
     "module_description": "DHCPv4 server daemon",
     "config_data": [
       { "item_name": "interface",
-        "item_type": "string",
+        "item_type": "list",
         "item_optional": false,
-        "item_default": "eth0"
+        "item_default": [ "all" ],
+        "list_item_spec":
+        {
+          "item_name": "interface_name",
+          "item_type": "string",
+          "item_optional": false,
+          "item_default": "all"
+        }
+      } ,
+
+      { "item_name": "renew-timer",
+        "item_type": "integer",
+        "item_optional": false,
+        "item_default": 1000
+      },
+
+      { "item_name": "rebind-timer",
+        "item_type": "integer",
+        "item_optional": false,
+        "item_default": 2000
+      },
+
+      { "item_name": "valid-lifetime",
+        "item_type": "integer",
+        "item_optional": false,
+        "item_default": 4000
+      },
+
+      { "item_name": "subnet4",
+        "item_type": "list",
+        "item_optional": false,
+        "item_default": [],
+        "list_item_spec":
+        {
+            "item_name": "single-subnet4",
+            "item_type": "map",
+            "item_optional": false,
+            "item_default": {},
+            "map_item_spec": [
+
+                { "item_name": "subnet",
+                  "item_type": "string",
+                  "item_optional": false,
+                  "item_default": ""
+                },
+
+                { "item_name": "renew-timer",
+                  "item_type": "integer",
+                  "item_optional": false,
+                  "item_default": 1000
+                },
+
+                { "item_name": "rebind-timer",
+                  "item_type": "integer",
+                  "item_optional": false,
+                  "item_default": 2000
+                },
+
+                { "item_name": "valid-lifetime",
+                  "item_type": "integer",
+                  "item_optional": false,
+                  "item_default": 7200
+                },
+                { "item_name": "pool",
+                  "item_type": "list",
+                  "item_optional": false,
+                  "item_default": [],
+                    "list_item_spec":
+                    {
+                        "item_name": "type",
+                        "item_type": "string",
+                        "item_optional": false,
+                        "item_default": ""
+                    }
+                }
+            ]
+        }
       }
     ],
     "commands": [

src/bin/dhcp4/dhcp4_messages.mes

@@ -26,10 +26,30 @@ to establish a session with the BIND 10 control channel.
 A debug message listing the command (and possible arguments) received
 from the BIND 10 control system by the IPv4 DHCP server.
 
+% DHCP4_CONFIG_LOAD_FAIL failed to load configuration: %1
+This critical error message indicates that the initial DHCPv4
+configuration has failed. The server will start, but nothing will be
+served until the configuration has been corrected.
+
 % DHCP4_CONFIG_UPDATE updated configuration received: %1
 A debug message indicating that the IPv4 DHCP server has received an
 updated configuration from the BIND 10 configuration system.
 
+% DHCP4_CONFIG_START DHCPv4 server is processing the following configuration: %1
+This is a debug message that is issued every time the server receives a
+configuration. That happens start up and also when a server configuration
+change is committed by the administrator.
+
+% DHCP4_CONFIG_NEW_SUBNET A new subnet has been added to configuration: %1
+This is an informational message reporting that the configuration has
+been extended to include the specified IPv4 subnet.
+
+% DHCP4_CONFIG_COMPLETE DHCPv4 server has completed configuration: %1
+This is an informational message announcing the successful processing of a
+new configuration. it is output during server startup, and when an updated
+configuration is committed by the administrator.  Additional information
+may be provided.
+
 % DHCP4_NOT_RUNNING IPv4 DHCP server is not running
 A warning message is issued when an attempt is made to shut down the
 IPv4 DHCP server but it is not running.

src/bin/dhcp4/tests/Makefile.am

@@ -49,9 +49,11 @@ TESTS += dhcp4_unittests
 
 dhcp4_unittests_SOURCES = ../dhcp4_srv.h ../dhcp4_srv.cc ../ctrl_dhcp4_srv.cc
 dhcp4_unittests_SOURCES += ../dhcp4_log.h ../dhcp4_log.cc
+dhcp4_unittests_SOURCES += ../config_parser.cc ../config_parser.h
 dhcp4_unittests_SOURCES += dhcp4_unittests.cc
 dhcp4_unittests_SOURCES += dhcp4_srv_unittest.cc
 dhcp4_unittests_SOURCES += ctrl_dhcp4_srv_unittest.cc
+dhcp4_unittests_SOURCES += config_parser_unittest.cc
 nodist_dhcp4_unittests_SOURCES = ../dhcp4_messages.h ../dhcp4_messages.cc
 
 if USE_CLANGPP
@@ -65,6 +67,7 @@ dhcp4_unittests_LDFLAGS = $(AM_LDFLAGS) $(GTEST_LDFLAGS)
 dhcp4_unittests_LDADD = $(GTEST_LDADD)
 dhcp4_unittests_LDADD += $(top_builddir)/src/lib/asiolink/libb10-asiolink.la
 dhcp4_unittests_LDADD += $(top_builddir)/src/lib/dhcp/libb10-dhcp++.la
+dhcp4_unittests_LDADD += $(top_builddir)/src/lib/dhcp/libb10-dhcpsrv.la
 dhcp4_unittests_LDADD += $(top_builddir)/src/lib/exceptions/libb10-exceptions.la
 dhcp4_unittests_LDADD += $(top_builddir)/src/lib/log/libb10-log.la
 dhcp4_unittests_LDADD += $(top_builddir)/src/lib/asiolink/libb10-asiolink.la

src/bin/dhcp4/tests/config_parser_unittest.cc

@@ -0,0 +1,236 @@
+// Copyright (C) 2012 Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include <config.h>
+#include <iostream>
+#include <fstream>
+#include <sstream>
+
+#include <arpa/inet.h>
+#include <gtest/gtest.h>
+
+#include <dhcp4/dhcp4_srv.h>
+#include <dhcp4/config_parser.h>
+#include <config/ccsession.h>
+#include <dhcp/subnet.h>
+#include <dhcp/cfgmgr.h>
+
+using namespace std;
+using namespace isc;
+using namespace isc::dhcp;
+using namespace isc::asiolink;
+using namespace isc::data;
+using namespace isc::config;
+
+namespace {
+
+class Dhcp4ParserTest : public ::testing::Test {
+public:
+    Dhcp4ParserTest()
+    :rcode_(-1) {
+        // Open port 0 means to not do anything at all. We don't want to
+        // deal with sockets here, just check if configuration handling
+        // is sane.
+        srv_ = new Dhcpv4Srv(0);
+    }
+
+    ~Dhcp4ParserTest() {
+        delete srv_;
+    };
+
+    Dhcpv4Srv* srv_;
+
+    int rcode_;
+    ConstElementPtr comment_;
+};
+
+// Goal of this test is a verification if a very simple config update
+// with just a bumped version number. That's the simplest possible
+// config update.
+TEST_F(Dhcp4ParserTest, version) {
+
+    ConstElementPtr x;
+
+    EXPECT_NO_THROW(x = configureDhcp4Server(*srv_,
+                    Element::fromJSON("{\"version\": 0}")));
+
+    // returned value must be 0 (configuration accepted)
+    ASSERT_TRUE(x);
+    comment_ = parseAnswer(rcode_, x);
+    EXPECT_EQ(0, rcode_);
+}
+
+/// The goal of this test is to verify that the code accepts only
+/// valid commands and malformed or unsupported parameters are rejected.
+TEST_F(Dhcp4ParserTest, bogus_command) {
+
+    ConstElementPtr x;
+
+    EXPECT_NO_THROW(x = configureDhcp4Server(*srv_,
+                    Element::fromJSON("{\"bogus\": 5}")));
+
+    // returned value must be 1 (configuration parse error)
+    ASSERT_TRUE(x);
+    comment_ = parseAnswer(rcode_, x);
+    EXPECT_EQ(1, rcode_);
+}
+
+/// The goal of this test is to verify if wrongly defined subnet will
+/// be rejected. Properly defined subnet must include at least one
+/// pool definition.
+TEST_F(Dhcp4ParserTest, empty_subnet) {
+
+    ConstElementPtr status;
+
+    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_,
+                    Element::fromJSON("{ \"interface\": [ \"all\" ],"
+                                      "\"preferred-lifetime\": 3000,"
+                                      "\"rebind-timer\": 2000, "
+                                      "\"renew-timer\": 1000, "
+                                      "\"subnet4\": [  ], "
+                                      "\"valid-lifetime\": 4000 }")));
+
+    // returned value should be 0 (success)
+    ASSERT_TRUE(status);
+    comment_ = parseAnswer(rcode_, status);
+    EXPECT_EQ(0, rcode_);
+}
+
+/// The goal of this test is to verify if defined subnet uses global
+/// parameter timer definitions.
+TEST_F(Dhcp4ParserTest, subnet_global_defaults) {
+
+    ConstElementPtr status;
+
+    string config = "{ \"interface\": [ \"all\" ],"
+        "\"rebind-timer\": 2000, "
+        "\"renew-timer\": 1000, "
+        "\"subnet4\": [ { "
+        "    \"pool\": [ \"192.0.2.1 - 192.0.2.100\" ],"
+        "    \"subnet\": \"192.0.2.0/24\" } ],"
+        "\"valid-lifetime\": 4000 }";
+    cout << config << endl;
+
+    ElementPtr json = Element::fromJSON(config);
+
+    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_, json));
+
+    // check if returned status is OK
+    ASSERT_TRUE(status);
+    comment_ = parseAnswer(rcode_, status);
+    EXPECT_EQ(0, rcode_);
+
+    // Now check if the configuration was indeed handled and we have
+    // expected pool configured.
+    Subnet4Ptr subnet = CfgMgr::instance().getSubnet4(IOAddress("192.0.2.200"));
+    ASSERT_TRUE(subnet);
+    EXPECT_EQ(1000, subnet->getT1());
+    EXPECT_EQ(2000, subnet->getT2());
+    EXPECT_EQ(4000, subnet->getValid());
+}
+
+// This test checks if it is possible to override global values
+// on a per subnet basis.
+TEST_F(Dhcp4ParserTest, subnet_local) {
+
+    ConstElementPtr status;
+
+    string config = "{ \"interface\": [ \"all\" ],"
+        "\"rebind-timer\": 2000, "
+        "\"renew-timer\": 1000, "
+        "\"subnet4\": [ { "
+        "    \"pool\": [ \"192.0.2.1 - 192.0.2.100\" ],"
+        "    \"renew-timer\": 1, "
+        "    \"rebind-timer\": 2, "
+        "    \"valid-lifetime\": 4,"
+        "    \"subnet\": \"192.0.2.0/24\" } ],"
+        "\"valid-lifetime\": 4000 }";
+    cout << config << endl;
+
+    ElementPtr json = Element::fromJSON(config);
+
+    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_, json));
+
+    // returned value should be 0 (configuration success)
+    ASSERT_TRUE(status);
+    comment_ = parseAnswer(rcode_, status);
+    EXPECT_EQ(0, rcode_);
+
+    Subnet4Ptr subnet = CfgMgr::instance().getSubnet4(IOAddress("192.0.2.200"));
+    ASSERT_TRUE(subnet);
+    EXPECT_EQ(1, subnet->getT1());
+    EXPECT_EQ(2, subnet->getT2());
+    EXPECT_EQ(4, subnet->getValid());
+}
+
+// Test verifies that a subnet with pool values that do not belong to that
+// pool are rejected.
+TEST_F(Dhcp4ParserTest, pool_out_of_subnet) {
+
+    ConstElementPtr status;
+
+    string config = "{ \"interface\": [ \"all\" ],"
+        "\"preferred-lifetime\": 3000,"
+        "\"rebind-timer\": 2000, "
+        "\"renew-timer\": 1000, "
+        "\"subnet4\": [ { "
+        "    \"pool\": [ \"192.0.4.0/28\" ],"
+        "    \"subnet\": \"192.0.2.0/24\" } ],"
+        "\"valid-lifetime\": 4000 }";
+    cout << config << endl;
+
+    ElementPtr json = Element::fromJSON(config);
+
+    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_, json));
+
+    // returned value must be 2 (values error)
+    // as the pool does not belong to that subnet
+    ASSERT_TRUE(status);
+    comment_ = parseAnswer(rcode_, status);
+    EXPECT_EQ(2, rcode_);
+}
+
+// Goal of this test is to verify if pools can be defined
+// using prefix/length notation. There is no separate test for min-max
+// notation as it was tested in several previous tests.
+TEST_F(Dhcp4ParserTest, pool_prefix_len) {
+
+    ConstElementPtr x;
+
+    string config = "{ \"interface\": [ \"all\" ],"
+        "\"rebind-timer\": 2000, "
+        "\"renew-timer\": 1000, "
+        "\"subnet4\": [ { "
+        "    \"pool\": [ \"192.0.2.128/28\" ],"
+        "    \"subnet\": \"192.0.2.0/24\" } ],"
+        "\"valid-lifetime\": 4000 }";
+    cout << config << endl;
+
+    ElementPtr json = Element::fromJSON(config);
+
+    EXPECT_NO_THROW(x = configureDhcp4Server(*srv_, json));
+
+    // returned value must be 1 (configuration parse error)
+    ASSERT_TRUE(x);
+    comment_ = parseAnswer(rcode_, x);
+    EXPECT_EQ(0, rcode_);
+
+    Subnet4Ptr subnet = CfgMgr::instance().getSubnet4(IOAddress("192.0.2.200"));
+    ASSERT_TRUE(subnet);
+    EXPECT_EQ(1000, subnet->getT1());
+    EXPECT_EQ(2000, subnet->getT2());
+    EXPECT_EQ(4000, subnet->getValid());
+}
+
+};

src/lib/dhcp/cfgmgr.cc

@@ -101,6 +101,14 @@ void CfgMgr::addSubnet4(const Subnet4Ptr& subnet) {
     subnets4_.push_back(subnet);
 }
 
+void CfgMgr::deleteSubnets4() {
+    subnets4_.clear();
+}
+
+void CfgMgr::deleteSubnets6() {
+    subnets6_.clear();
+}
+
 CfgMgr::CfgMgr() {
 }
 

src/lib/dhcp/cfgmgr.h

@@ -99,9 +99,9 @@ public:
     /// needed is a dynamic server reconfiguration - a use case that is not
     /// planned to be supported any time soon.
 
-    /// @brief removes all subnets
+    /// @brief removes all IPv6 subnets
     ///
-    /// This method removes all existing subnets. It is used during
+    /// This method removes all existing IPv6 subnets. It is used during
     /// reconfiguration - old configuration is wiped and new definitions
     /// are used to recreate subnets.
     ///
@@ -109,9 +109,7 @@ public:
     /// between old and new configuration is tricky. For example: is
     /// 2000::/64 and 2000::/48 the same subnet or is it something
     /// completely new?
-    void deleteSubnets6() {
-        subnets6_.clear();
-    }
+    void deleteSubnets6();
 
     /// @brief get IPv4 subnet by address
     ///
@@ -128,7 +126,16 @@ public:
     void addSubnet4(const Subnet4Ptr& subnet);
 
     /// @brief removes all IPv4 subnets
-    void removeSubnets4();
+    ///
+    /// This method removes all existing IPv4 subnets. It is used during
+    /// reconfiguration - old configuration is wiped and new definitions
+    /// are used to recreate subnets.
+    ///
+    /// @todo Implement more intelligent approach. Note that comparison
+    /// between old and new configuration is tricky. For example: is
+    /// 192.0.2.0/23 and 192.0.2.0/24 the same subnet or is it something
+    /// completely new?
+    void deleteSubnets4();
 protected:
 
     /// @brief Protected constructor.