kea/src/lib/dhcpsrv/parsers/dhcp_parsers.cc

// Copyright (C) 2013-2017 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/.

#include <config.h>

#include <dhcp/iface_mgr.h>
#include <dhcp/libdhcp++.h>
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/cfg_option.h>
#include <dhcpsrv/dhcpsrv_log.h>
#include <dhcpsrv/parsers/dhcp_parsers.h>
#include <dhcpsrv/parsers/host_reservation_parser.h>
#include <dhcpsrv/parsers/host_reservations_list_parser.h>
#include <dhcpsrv/parsers/option_data_parser.h>
#include <dhcpsrv/cfg_mac_source.h>
#include <util/encode/hex.h>
#include <util/strutil.h>

#include <boost/algorithm/string.hpp>
#include <boost/foreach.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/scoped_ptr.hpp>

#include <map>
#include <string>
#include <vector>

using namespace std;
using namespace isc::asiolink;
using namespace isc::data;
using namespace isc::util;

namespace isc {
namespace dhcp {

// **************************** DebugParser *************************

DebugParser::DebugParser(const std::string& param_name)
    :param_name_(param_name) {
}

void
DebugParser::build(ConstElementPtr new_config) {
    value_ = new_config;
    std::cout << "Build for token: [" << param_name_ << "] = ["
        << value_->str() << "]" << std::endl;
}

void
DebugParser::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;
}

// **************************** BooleanParser  *************************

template<> void ValueParser<bool>::build(isc::data::ConstElementPtr value) {
    // Invoke common code for all specializations of build().
    buildCommon(value);
    // The Config Manager checks if user specified a
    // valid value for a boolean parameter: true or false.
    // We should have a boolean Element, use value directly
    try {
        value_ = value->boolValue();
    } catch (const isc::data::TypeError &) {
        isc_throw(BadValue, " Wrong value type for " << param_name_
                  << " : build called with a non-boolean element "
                  << "(" << value->getPosition() << ").");
    }
}

// **************************** Uin32Parser  *************************

template<> void ValueParser<uint32_t>::build(ConstElementPtr value) {
    // Invoke common code for all specializations of build().
    buildCommon(value);

    int64_t check;
    string x = value->str();
    try {
        check = boost::lexical_cast<int64_t>(x);
    } catch (const boost::bad_lexical_cast &) {
        isc_throw(BadValue, "Failed to parse value " << value->str()
                  << " as unsigned 32-bit integer "
                  "(" << value->getPosition() << ").");
    }
    if (check > std::numeric_limits<uint32_t>::max()) {
        isc_throw(BadValue, "Value " << value->str() << " is too large"
                  " for unsigned 32-bit integer "
                  "(" << value->getPosition() << ").");
    }
    if (check < 0) {
        isc_throw(BadValue, "Value " << value->str() << " is negative."
               << " Only 0 or larger are allowed for unsigned 32-bit integer "
                  "(" << value->getPosition() << ").");
    }

    // value is small enough to fit
    value_ = static_cast<uint32_t>(check);
}

// **************************** StringParser  *************************

template <> void ValueParser<std::string>::build(ConstElementPtr value) {
    // Invoke common code for all specializations of build().
    buildCommon(value);

    // For strings we need to use stringValue() rather than str().
    // str() returns fully escaped special characters, so
    // single backslash would be misrepresented as "\\".
    if (value->getType() == Element::string) {
        value_ = value->stringValue();
    } else {
        value_ = value->str();
    }
    boost::erase_all(value_, "\"");
}

// ******************** MACSourcesListConfigParser *************************

void
MACSourcesListConfigParser::parse(CfgMACSource& mac_sources, ConstElementPtr value) {
    CfgIface cfg_iface;
    uint32_t source = 0;
    size_t cnt = 0;

    // By default, there's only one source defined: ANY.
    // If user specified anything, we need to get rid of that default.
    mac_sources.clear();

    BOOST_FOREACH(ConstElementPtr source_elem, value->listValue()) {
        std::string source_str = source_elem->stringValue();
        try {
            source = CfgMACSource::MACSourceFromText(source_str);
            mac_sources.add(source);
            ++cnt;
        } catch (const InvalidParameter& ex) {
            isc_throw(DhcpConfigError, "The mac-sources value '" << source_str
                      << "' was specified twice (" << value->getPosition() << ")");
        } catch (const std::exception& ex) {
            isc_throw(DhcpConfigError, "Failed to convert '"
                      << source_str << "' to any recognized MAC source:"
                      << ex.what() << " (" << value->getPosition() << ")");
        }
    }

    if (!cnt) {
        isc_throw(DhcpConfigError, "If specified, MAC Sources cannot be empty");
    }
}

// ******************** ControlSocketParser *************************
void ControlSocketParser::parse(SrvConfig& srv_cfg, isc::data::ConstElementPtr value) {
    if (!value) {
        isc_throw(DhcpConfigError, "Logic error: specified control-socket is null");
    }

    if (value->getType() != Element::map) {
        isc_throw(DhcpConfigError, "Specified control-socket is expected to be a map"
                  ", i.e. a structure defined within { }");
    }
    srv_cfg.setControlSocketInfo(value);
}







template<typename SearchKey>
OptionDefinitionPtr
OptionDataParser::findOptionDefinition(const std::string& option_space,
                                       const SearchKey& search_key) const {
    OptionDefinitionPtr def = LibDHCP::getOptionDef(option_space, search_key);

    if (!def) {
        // Check if this is a vendor-option. If it is, get vendor-specific
        // definition.
        uint32_t vendor_id = LibDHCP::optionSpaceToVendorId(option_space);
        if (vendor_id) {
            const Option::Universe u = address_family_ == AF_INET ?
                Option::V4 : Option::V6;
            def = LibDHCP::getVendorOptionDef(u, vendor_id, search_key);
        }
    }

    if (!def) {
        // Check if this is an option specified by a user.
        def = CfgMgr::instance().getStagingCfg()->getCfgOptionDef()
            ->get(option_space, search_key);
    }

    return (def);
}

// ******************************** OptionDefParser ****************************

std::pair<isc::dhcp::OptionDefinitionPtr, std::string>
OptionDefParser::parse(ConstElementPtr option_def) {

    // Get mandatory parameters.
    std::string name = getString(option_def, "name");
    uint32_t code = getInteger(option_def, "code");
    std::string type = getString(option_def, "type");

    // Get optional parameters. Whoever called this parser, should have
    // called SimpleParser::setDefaults first.
    bool array_type = getBoolean(option_def, "array");
    std::string record_types = getString(option_def, "record-types");
    std::string space = getString(option_def, "space");
    std::string encapsulates = getString(option_def, "encapsulate");

    if (!OptionSpace::validateName(space)) {
        isc_throw(DhcpConfigError, "invalid option space name '"
                  << space << "' ("
                  << getPosition("space", option_def) << ")");
    }

    // Create option definition.
    OptionDefinitionPtr def;
    // We need to check if user has set encapsulated option space
    // name. If so, different constructor will be used.
    if (!encapsulates.empty()) {
        // Arrays can't be used together with sub-options.
        if (array_type) {
            isc_throw(DhcpConfigError, "option '" << space << "."
                      << "name" << "', comprising an array of data"
                      << " fields may not encapsulate any option space ("
                      << option_def->getPosition() << ")");

        } else if (encapsulates == space) {
            isc_throw(DhcpConfigError, "option must not encapsulate"
                      << " an option space it belongs to: '"
                      << space << "." << name << "' is set to"
                      << " encapsulate '" << space << "' ("
                      << option_def->getPosition() << ")");

        } else {
            def.reset(new OptionDefinition(name, code, type,
                        encapsulates.c_str()));
        }

    } else {
        def.reset(new OptionDefinition(name, code, type, array_type));

    }

    // Split the list of record types into tokens.
    std::vector<std::string> record_tokens =
    isc::util::str::tokens(record_types, ",");
    // Iterate over each token and add a record type into
    // option definition.
    BOOST_FOREACH(std::string record_type, record_tokens) {
        try {
            boost::trim(record_type);
            if (!record_type.empty()) {
                    def->addRecordField(record_type);
            }
        } catch (const Exception& ex) {
            isc_throw(DhcpConfigError, "invalid record type values"
                      << " specified for the option definition: "
                      << ex.what() << " ("
                      << getPosition("record-types", option_def) << ")");
        }
    }

    // Validate the definition.
    try {
        def->validate();
    } catch (const std::exception& ex) {
        isc_throw(DhcpConfigError, ex.what()
                  << " (" << option_def->getPosition() << ")");
    }

    // Option definition has been created successfully.
    return make_pair(def, space);
}

// ******************************** OptionDefListParser ************************
void
OptionDefListParser::parse(CfgOptionDefPtr storage, ConstElementPtr option_def_list) {
    if (!option_def_list) {
        isc_throw(DhcpConfigError, "parser error: a pointer to a list of"
                  << " option definitions is NULL ("
                  << option_def_list->getPosition() << ")");
    }

    OptionDefParser parser;
    BOOST_FOREACH(ConstElementPtr option_def, option_def_list->listValue()) {
        OptionDefinitionTuple def;

        def = parser.parse(option_def);
        try {
            storage->add(def.first, def.second);
        } catch (const std::exception& ex) {
            // Append position if there is a failure.
            isc_throw(DhcpConfigError, ex.what() << " ("
                      << option_def->getPosition() << ")");
        }
    }

    // All definitions have been prepared. Put them as runtime options into
    // the libdhcp++.
    LibDHCP::setRuntimeOptionDefs(storage->getContainer());
}

//****************************** RelayInfoParser ********************************
RelayInfoParser::RelayInfoParser(const Option::Universe& family)
    : family_(family) {
};

void
RelayInfoParser::parse(const isc::dhcp::Subnet::RelayInfoPtr& cfg,
                       ConstElementPtr relay_info) {
    // There is only one parameter which is mandatory
    IOAddress ip = getAddress(relay_info, "ip-address");

    // Check if the address family matches.
    if ((ip.isV4() && family_ != Option::V4) ||
        (ip.isV6() && family_ != Option::V6) ) {
        isc_throw(DhcpConfigError, "ip-address field " << ip.toText()
                  << " does not have IP address of expected family type: "
                  << (family_ == Option::V4 ? "IPv4" : "IPv6")
                  << " (" << getPosition("ip-address", relay_info) << ")");
    }

    // Ok, we're done with parsing. Let's store the result in the structure
    // we were given as configuration storage.
    *cfg = isc::dhcp::Subnet::RelayInfo(ip);
}

//****************************** PoolParser ********************************

void
PoolParser::parse(PoolStoragePtr pools,
                  ConstElementPtr pool_structure,
                  const uint16_t address_family) {

    ConstElementPtr text_pool = pool_structure->get("pool");

    if (!text_pool) {
        isc_throw(DhcpConfigError, "Mandatory 'pool' entry missing in "
                  "definition: (" << pool_structure->getPosition() << ")");
    }

    // 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

    PoolPtr pool;

    // Is this prefix/len notation?
    size_t pos = txt.find("/");
    if (pos != string::npos) {
        isc::asiolink::IOAddress addr("::");
        uint8_t len = 0;
        try {
            addr = isc::asiolink::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, here we only check
            // the representation fits in an uint8_t as this can't
            // be done by a direct lexical cast as explained...
            int val_len = boost::lexical_cast<int>(prefix_len);
            if ((val_len < std::numeric_limits<uint8_t>::min()) ||
                (val_len > std::numeric_limits<uint8_t>::max())) {
                // This exception will be handled 4 line later!
                isc_throw(OutOfRange, "");
            }
            len = static_cast<uint8_t>(val_len);
        } catch (...)  {
            isc_throw(DhcpConfigError, "Failed to parse pool "
                      "definition: " << txt << " ("
                      << text_pool->getPosition() << ")");
        }

        try {
            pool = poolMaker(addr, len);
            pools->push_back(pool);
        } catch (const std::exception& ex) {
            isc_throw(DhcpConfigError, "Failed to create pool defined by: "
                      << txt << " (" << text_pool->getPosition() << ")");
        }

    } else {
        isc::asiolink::IOAddress min("::");
        isc::asiolink::IOAddress max("::");

        // Is this min-max notation?
        pos = txt.find("-");
        if (pos != string::npos) {
            // using min-max notation
            try {
                min = isc::asiolink::IOAddress(txt.substr(0, pos));
                max = isc::asiolink::IOAddress(txt.substr(pos + 1));
            } catch (...)  {
                isc_throw(DhcpConfigError, "Failed to parse pool "
                          "definition: " << txt << " ("
                          << text_pool->getPosition() << ")");
            }

            try {
                pool = poolMaker(min, max);
                pools->push_back(pool);
            } catch (const std::exception& ex) {
                isc_throw(DhcpConfigError, "Failed to create pool defined by: "
                          << txt << " (" << text_pool->getPosition() << ")");
            }
        }
    }

    if (!pool) {
        isc_throw(DhcpConfigError, "invalid pool definition: "
                  << text_pool->stringValue() <<
                  ". There are two acceptable formats <min address-max address>"
                  " or <prefix/len> ("
                  << text_pool->getPosition() << ")");
    }

    // If there's user-context specified, store it.
    ConstElementPtr user_context = pool_structure->get("user-context");
    if (user_context) {
        if (user_context->getType() != Element::map) {
            isc_throw(isc::dhcp::DhcpConfigError, "User context has to be a map ("
                      << user_context->getPosition() << ")");
        }
        pool->setContext(user_context);
    }

    // Parser pool specific options.
    ConstElementPtr option_data = pool_structure->get("option-data");
    if (option_data) {
        try {
            CfgOptionPtr cfg = pool->getCfgOption();
            OptionDataListParser option_parser(address_family);
            option_parser.parse(cfg, option_data);
        } catch (const std::exception& ex) {
            isc_throw(isc::dhcp::DhcpConfigError, ex.what()
                      << " (" << option_data->getPosition() << ")");
        }
    }
}

//****************************** Pool4Parser *************************

PoolPtr
Pool4Parser::poolMaker (IOAddress &addr, uint32_t len, int32_t) {
    return (PoolPtr(new Pool4(addr, len)));
}

PoolPtr
Pool4Parser::poolMaker (IOAddress &min, IOAddress &max, int32_t) {
    return (PoolPtr(new Pool4(min, max)));
}

//****************************** Pool4ListParser *************************

void
Pools4ListParser::parse(PoolStoragePtr pools, ConstElementPtr pools_list) {
    BOOST_FOREACH(ConstElementPtr pool, pools_list->listValue()) {
        Pool4Parser parser;
        parser.parse(pools, pool, AF_INET);
    }
}

//****************************** SubnetConfigParser *************************

SubnetConfigParser::SubnetConfigParser(uint16_t family)
    : pools_(new PoolStorage()),
      address_family_(family),
      options_(new CfgOption()) {
    string addr = family == AF_INET ? "0.0.0.0" : "::";
    relay_info_.reset(new isc::dhcp::Subnet::RelayInfo(IOAddress(addr)));
}

SubnetPtr
SubnetConfigParser::parse(ConstElementPtr subnet) {

    ConstElementPtr options_params = subnet->get("option-data");
    if (options_params) {
        OptionDataListParser opt_parser(address_family_);
        opt_parser.parse(options_, options_params);
    }

    ConstElementPtr relay_params = subnet->get("relay");
    if (relay_params) {
        Option::Universe u = (address_family_ == AF_INET) ? Option::V4 : Option::V6;
        RelayInfoParser parser(u);
        parser.parse(relay_info_, relay_params);
    }

    // Create a subnet.
    try {
        createSubnet(subnet);
    } catch (const std::exception& ex) {
        isc_throw(DhcpConfigError,
                  "subnet configuration failed: " << ex.what());
    }

    return (subnet_);
}

Subnet::HRMode
SubnetConfigParser::hrModeFromText(const std::string& txt) {
    if ( (txt.compare("disabled") == 0) ||
         (txt.compare("off") == 0) )  {
        return (Subnet::HR_DISABLED);
    } else if (txt.compare("out-of-pool") == 0) {
        return (Subnet::HR_OUT_OF_POOL);
    } else if (txt.compare("all") == 0) {
        return (Subnet::HR_ALL);
    } else {
        isc_throw(BadValue, "Can't convert '" << txt
                  << "' into any valid reservation-mode values");
    }
}

void
SubnetConfigParser::createSubnet(ConstElementPtr params) {
    std::string subnet_txt;
    try {
        subnet_txt = getString(params, "subnet");
    } catch (const DhcpConfigError &) {
        // rethrow with precise error
        isc_throw(DhcpConfigError,
                 "mandatory 'subnet' parameter is missing for a subnet being"
                  " configured (" << params->getPosition() << ")");
    }

    // Remove any spaces or tabs.
    boost::erase_all(subnet_txt, " ");
    boost::erase_all(subnet_txt, "\t");

    // The subnet format is prefix/len. We are going to extract
    // the prefix portion of a subnet string to create IOAddress
    // object from it. IOAddress will be passed to the Subnet's
    // constructor later on. In order to extract the prefix we
    // need to get all characters preceding "/".
    size_t pos = subnet_txt.find("/");
    if (pos == string::npos) {
        ConstElementPtr elem = params->get("subnet");
        isc_throw(DhcpConfigError,
                  "Invalid subnet syntax (prefix/len expected):" << subnet_txt
                  << " (" << elem->getPosition() << ")");
    }

    // Try to create the address object. It also validates that
    // the address syntax is ok.
    isc::asiolink::IOAddress addr(subnet_txt.substr(0, pos));
    uint8_t len = boost::lexical_cast<unsigned int>(subnet_txt.substr(pos + 1));

    // Call the subclass's method to instantiate the subnet
    initSubnet(params, addr, len);

    // Add pools to it.
    for (PoolStorage::iterator it = pools_->begin(); it != pools_->end();
         ++it) {
        try {
            subnet_->addPool(*it);
        } catch (const BadValue& ex) {
            // addPool() can throw BadValue if the pool is overlapping or
            // is out of bounds for the subnet.
            isc_throw(DhcpConfigError,
                      ex.what() << " (" << params->getPosition() << ")");
        }
    }

    // Now configure parameters that are common for v4 and v6:

    // Get interface name. If it is defined, then the subnet is available
    // directly over specified network interface.
    std::string iface = getString(params, "interface");
    if (!iface.empty()) {
        if (!IfaceMgr::instance().getIface(iface)) {
            ConstElementPtr error = params->get("interface");
            isc_throw(DhcpConfigError, "Specified network interface name " << iface
                      << " for subnet " << subnet_->toText()
                      << " is not present in the system ("
                      << error->getPosition() << ")");
        }

        subnet_->setIface(iface);
    }

    // Let's set host reservation mode. If not specified, the default value of
    // all will be used.
    try {
        std::string hr_mode = getString(params, "reservation-mode");
        subnet_->setHostReservationMode(hrModeFromText(hr_mode));
    } catch (const BadValue& ex) { 
       isc_throw(DhcpConfigError, "Failed to process specified value "
                  " of reservation-mode parameter: " << ex.what()
                  << "(" << getPosition("reservation-mode", params) << ")");
    }

    // Try setting up client class.
    string client_class = getString(params, "client-class");
    if (!client_class.empty()) {
        subnet_->allowClientClass(client_class);
    }

    // If there's user-context specified, store it.
    ConstElementPtr user_context = params->get("user-context");
    if (user_context) {
        if (user_context->getType() != Element::map) {
            isc_throw(isc::dhcp::DhcpConfigError, "User context has to be a map ("
                      << user_context->getPosition() << ")");
        }
        subnet_->setContext(user_context);
    }

    // Here globally defined options were merged to the subnet specific
    // options but this is no longer the case (they have a different
    // and not consecutive priority).

    // Copy options to the subnet configuration.
    options_->copyTo(*subnet_->getCfgOption());
}

//****************************** Subnet4ConfigParser *************************

Subnet4ConfigParser::Subnet4ConfigParser()
    :SubnetConfigParser(AF_INET) {
}

Subnet4Ptr
Subnet4ConfigParser::parse(ConstElementPtr subnet) {
    /// Parse Pools first.
    ConstElementPtr pools = subnet->get("pools");
    if (pools) {
        Pools4ListParser parser;
        parser.parse(pools_, pools);
    }

    SubnetPtr generic = SubnetConfigParser::parse(subnet);

    if (!generic) {
        isc_throw(DhcpConfigError,
                  "Failed to create an IPv4 subnet (" <<
                  subnet->getPosition() << ")");
    }

    Subnet4Ptr sn4ptr = boost::dynamic_pointer_cast<Subnet4>(subnet_);
    if (!sn4ptr) {
        // If we hit this, it is a programming error.
        isc_throw(Unexpected,
                  "Invalid Subnet4 cast in Subnet4ConfigParser::parse");
    }

    // Set relay information if it was parsed
    if (relay_info_) {
        sn4ptr->setRelayInfo(*relay_info_);
    }

    // Parse Host Reservations for this subnet if any.
    ConstElementPtr reservations = subnet->get("reservations");
    if (reservations) {
        HostCollection hosts;
        HostReservationsListParser<HostReservationParser4> parser;
        parser.parse(subnet_->getID(), reservations, hosts);
        for (auto h = hosts.begin(); h != hosts.end(); ++h) {
            CfgMgr::instance().getStagingCfg()->getCfgHosts()->add(*h);
        }
    }

    return (sn4ptr);
}

void
Subnet4ConfigParser::initSubnet(data::ConstElementPtr params,
                                asiolink::IOAddress addr, uint8_t len) {
    // The renew-timer and rebind-timer are optional. If not set, the
    // option 58 and 59 will not be sent to a client. In this case the
    // client will use default values based on the valid-lifetime.
    Triplet<uint32_t> t1 = getInteger(params, "renew-timer");
    Triplet<uint32_t> t2 = getInteger(params, "rebind-timer");

    // The valid-lifetime is mandatory. It may be specified for a
    // particular subnet. If not, the global value should be present.
    // If there is no global value, exception is thrown.
    Triplet<uint32_t> valid = getInteger(params, "valid-lifetime");

    // Subnet ID is optional. If it is not supplied the value of 0 is used,
    // which means autogenerate. The value was inserted earlier by calling
    // SimpleParser4::setAllDefaults.
    SubnetID subnet_id = static_cast<SubnetID>(getInteger(params, "id"));

    stringstream s;
    s << addr << "/" << static_cast<int>(len) << " with params: ";
    // t1 and t2 are optional may be not specified.
    if (!t1.unspecified()) {
        s << "t1=" << t1 << ", ";
    }
    if (!t2.unspecified()) {
        s << "t2=" << t2 << ", ";
    }
    s <<"valid-lifetime=" << valid;

    LOG_INFO(dhcpsrv_logger, DHCPSRV_CFGMGR_NEW_SUBNET4).arg(s.str());

    Subnet4Ptr subnet4(new Subnet4(addr, len, t1, t2, valid, subnet_id));
    subnet_ = subnet4;

    // Set the match-client-id value for the subnet. It is always present.
    // If not explicitly specified, the default value was filled in when
    // SimpleParser4::setAllDefaults was called.
    bool match_client_id = getBoolean(params, "match-client-id");
    subnet4->setMatchClientId(match_client_id);

    // Set next-server. The default value is 0.0.0.0. Nevertheless, the
    // user could have messed that up by specifying incorrect value.
    // To avoid using 0.0.0.0, user can specify "".
    string next_server;
    try {
        next_server = getString(params, "next-server");
        if (!next_server.empty()) {
            subnet4->setSiaddr(IOAddress(next_server));
        }
    } catch (...) {
        ConstElementPtr next = params->get("next-server");
        string pos;
        if (next) {
            pos = next->getPosition().str();
        } else {
            pos = params->getPosition().str();
        }
        isc_throw(DhcpConfigError, "invalid parameter next-server : "
                  << next_server << "(" << pos << ")");
    }

    // 4o6 specific parameter: 4o6-interface. If not explicitly specified,
    // it will have the default value of "".
    string iface4o6 = getString(params, "4o6-interface");
    if (!iface4o6.empty()) {
        subnet4->get4o6().setIface4o6(iface4o6);
        subnet4->get4o6().enabled(true);
    }

    // 4o6 specific parameter: 4o6-subnet. If not explicitly specified, it
    // will have the default value of "".
    string subnet4o6 = getString(params, "4o6-subnet");
    if (!subnet4o6.empty()) {
        size_t slash = subnet4o6.find("/");
        if (slash == std::string::npos) {
            isc_throw(DhcpConfigError, "Missing / in the 4o6-subnet parameter:"
                      << subnet4o6 << ", expected format: prefix6/length");
        }
        string prefix = subnet4o6.substr(0, slash);
        string lenstr = subnet4o6.substr(slash + 1);

        uint8_t len = 128;
        try {
            len = boost::lexical_cast<unsigned int>(lenstr.c_str());
        } catch (const boost::bad_lexical_cast &) {
            isc_throw(DhcpConfigError, "Invalid prefix length specified in "
                      "4o6-subnet parameter: " << subnet4o6 << ", expected 0..128 value");
        }
        subnet4->get4o6().setSubnet4o6(IOAddress(prefix), len);
        subnet4->get4o6().enabled(true);
    }

    // Try 4o6 specific parameter: 4o6-interface-id
    std::string ifaceid = getString(params, "4o6-interface-id");
    if (!ifaceid.empty()) {
        OptionBuffer tmp(ifaceid.begin(), ifaceid.end());
        OptionPtr opt(new Option(Option::V6, D6O_INTERFACE_ID, tmp));
        subnet4->get4o6().setInterfaceId(opt);
        subnet4->get4o6().enabled(true);
    }

    /// client-class processing is now generic and handled in the common
    /// code (see isc::data::SubnetConfigParser::createSubnet)
}

//**************************** Subnets4ListConfigParser **********************

size_t
Subnets4ListConfigParser::parse(SrvConfigPtr cfg, ConstElementPtr subnets_list) {
    size_t cnt = 0;
    BOOST_FOREACH(ConstElementPtr subnet_json, subnets_list->listValue()) {

        Subnet4ConfigParser parser;
        Subnet4Ptr subnet = parser.parse(subnet_json);
        if (subnet) {

            // Adding a subnet to the Configuration Manager may fail if the
            // subnet id is invalid (duplicate). Thus, we catch exceptions
            // here to append a position in the configuration string.
            try {
                cfg->getCfgSubnets4()->add(subnet);
                cnt++;
            } catch (const std::exception& ex) {
                isc_throw(DhcpConfigError, ex.what() << " ("
                          << subnet_json->getPosition() << ")");
            }
        }
    }
    return (cnt);
}

//**************************** Pool6Parser *********************************

PoolPtr
Pool6Parser::poolMaker (IOAddress &addr, uint32_t len, int32_t ptype)
{
    return (PoolPtr(new Pool6(static_cast<isc::dhcp::Lease::Type>
                              (ptype), addr, len)));
}

PoolPtr
Pool6Parser::poolMaker (IOAddress &min, IOAddress &max, int32_t ptype)
{
    return (PoolPtr(new Pool6(static_cast<isc::dhcp::Lease::Type>
                              (ptype), min, max)));
}


//**************************** Pool6ListParser ***************************

void
Pools6ListParser::parse(PoolStoragePtr pools, ConstElementPtr pools_list) {
    BOOST_FOREACH(ConstElementPtr pool, pools_list->listValue()) {
        Pool6Parser parser;
        parser.parse(pools, pool, AF_INET6);
    }
}

//**************************** PdPoolParser ******************************

PdPoolParser::PdPoolParser() : options_(new CfgOption()) {
}

void
PdPoolParser::parse(PoolStoragePtr pools, ConstElementPtr pd_pool_) {
    std::string addr_str = getString(pd_pool_, "prefix");

    uint8_t prefix_len = getUint8(pd_pool_, "prefix-len");

    uint8_t delegated_len = getUint8(pd_pool_, "delegated-len");

    std::string excluded_prefix_str = "::";
    if (pd_pool_->contains("excluded-prefix")) {
        excluded_prefix_str = getString(pd_pool_, "excluded-prefix");
    }

    uint8_t excluded_prefix_len = 0;
    if (pd_pool_->contains("excluded-prefix-len")) {
        excluded_prefix_len = getUint8(pd_pool_, "excluded-prefix-len");
    }

    ConstElementPtr option_data = pd_pool_->get("option-data");
    if (option_data) {
        OptionDataListParser opts_parser(AF_INET6);
        opts_parser.parse(options_, option_data);
    }
                    
    ConstElementPtr user_context = pd_pool_->get("user-context");
    if (user_context) {
        user_context_ = user_context;
    }

    // Check the pool parameters. It will throw an exception if any
    // of the required parameters are invalid.
    try {
        // Attempt to construct the local pool.
        pool_.reset(new Pool6(IOAddress(addr_str),
                              prefix_len,
                              delegated_len,
                              IOAddress(excluded_prefix_str),
                              excluded_prefix_len));
        // Merge options specified for a pool into pool configuration.
        options_->copyTo(*pool_->getCfgOption());
    } catch (const std::exception& ex) {
        // Some parameters don't exist or are invalid. Since we are not
        // aware whether they don't exist or are invalid, let's append
        // the position of the pool map element.
        isc_throw(isc::dhcp::DhcpConfigError, ex.what()
                  << " (" << pd_pool_->getPosition() << ")");
    }

    if (user_context_) {
        pool_->setContext(user_context_);
    }

    // Add the local pool to the external storage ptr.
    pools->push_back(pool_);
}

//**************************** PdPoolsListParser ************************

void
PdPoolsListParser::parse(PoolStoragePtr pools, ConstElementPtr pd_pool_list) {
    // Loop through the list of pd pools.
    BOOST_FOREACH(ConstElementPtr pd_pool, pd_pool_list->listValue()) {
        PdPoolParser parser;
        parser.parse(pools, pd_pool);
    }
}

//**************************** Subnet6ConfigParser ***********************

Subnet6ConfigParser::Subnet6ConfigParser()
    :SubnetConfigParser(AF_INET6) {
}

Subnet6Ptr
Subnet6ConfigParser::parse(ConstElementPtr subnet) {
    /// Parse all pools first.
    ConstElementPtr pools = subnet->get("pools");
    if (pools) {
        Pools6ListParser parser;
        parser.parse(pools_, pools);
    }
    ConstElementPtr pd_pools = subnet->get("pd-pools");
    if (pd_pools) {
        PdPoolsListParser parser;
        parser.parse(pools_, pd_pools);
    }

    SubnetPtr generic = SubnetConfigParser::parse(subnet);

    if (!generic) {
        isc_throw(DhcpConfigError,
                  "Failed to create an IPv6 subnet (" <<
                  subnet->getPosition() << ")");
    }

    Subnet6Ptr sn6ptr = boost::dynamic_pointer_cast<Subnet6>(subnet_);
    if (!sn6ptr) {
        // If we hit this, it is a programming error.
        isc_throw(Unexpected,
                  "Invalid Subnet6 cast in Subnet6ConfigParser::parse");
    }

    // Set relay information if it was provided
    if (relay_info_) {
        sn6ptr->setRelayInfo(*relay_info_);
    }


    // Parse Host Reservations for this subnet if any.
    ConstElementPtr reservations = subnet->get("reservations");
    if (reservations) {
        HostCollection hosts;
        HostReservationsListParser<HostReservationParser6> parser;
        parser.parse(subnet_->getID(), reservations, hosts);
        for (auto h = hosts.begin(); h != hosts.end(); ++h) {
            CfgMgr::instance().getStagingCfg()->getCfgHosts()->add(*h);
        }
    }

    return (sn6ptr);
}

void
Subnet6ConfigParser::duplicate_option_warning(uint32_t code,
                                              asiolink::IOAddress& addr) {
    LOG_WARN(dhcpsrv_logger, DHCPSRV_CFGMGR_OPTION_DUPLICATE)
        .arg(code).arg(addr.toText());
}

void
Subnet6ConfigParser::initSubnet(data::ConstElementPtr params,
                                asiolink::IOAddress addr, uint8_t len) {
    // Get all 'time' parameters using inheritance.
    // If the subnet-specific value is defined then use it, else
    // use the global value. The global value must always be
    // present. If it is not, it is an internal error and exception
    // is thrown.
    Triplet<uint32_t> t1 = getInteger(params, "renew-timer");
    Triplet<uint32_t> t2 = getInteger(params, "rebind-timer");
    Triplet<uint32_t> pref = getInteger(params, "preferred-lifetime");
    Triplet<uint32_t> valid = getInteger(params, "valid-lifetime");

    // Subnet ID is optional. If it is not supplied the value of 0 is used,
    // which means autogenerate. The value was inserted earlier by calling
    // SimpleParser6::setAllDefaults.
    SubnetID subnet_id = static_cast<SubnetID>(getInteger(params, "id"));

    // We want to log whether rapid-commit is enabled, so we get this
    // before the actual subnet creation.
    bool rapid_commit = getBoolean(params, "rapid-commit");

    std::ostringstream output;
    output << addr << "/" << static_cast<int>(len)
           << " with params t1=" << t1 << ", t2="
           << t2 << ", preferred-lifetime=" << pref
           << ", valid-lifetime=" << valid
           << ", rapid-commit is " << (rapid_commit ? "enabled" : "disabled");


    LOG_INFO(dhcpsrv_logger, DHCPSRV_CFGMGR_NEW_SUBNET4).arg(output.str());

    // Create a new subnet.
    Subnet6* subnet6 = new Subnet6(addr, len, t1, t2, pref, valid,
                                       subnet_id);
    subnet_.reset(subnet6);

    // Enable or disable Rapid Commit option support for the subnet.
    subnet6->setRapidCommit(rapid_commit);

    // Get interface-id option content. For now we support string
    // representation only
    std::string ifaceid = getString(params, "interface-id");
    std::string iface = getString(params, "interface");

    // Specifying both interface for locally reachable subnets and
    // interface id for relays is mutually exclusive. Need to test for
    // this condition.
    if (!ifaceid.empty() && !iface.empty()) {
        isc_throw(isc::dhcp::DhcpConfigError,
                  "parser error: interface (defined for locally reachable "
                  "subnets) and interface-id (defined for subnets reachable"
                  " via relays) cannot be defined at the same time for "
                  "subnet " << addr << "/" << (int)len << "("
                  << params->getPosition() << ")");
    }

    // Configure interface-id for remote interfaces, if defined
    if (!ifaceid.empty()) {
        OptionBuffer tmp(ifaceid.begin(), ifaceid.end());
        OptionPtr opt(new Option(Option::V6, D6O_INTERFACE_ID, tmp));
        subnet6->setInterfaceId(opt);
    }

    /// client-class processing is now generic and handled in the common
    /// code (see isc::data::SubnetConfigParser::createSubnet)
}

//**************************** Subnet6ListConfigParser ********************

size_t
Subnets6ListConfigParser::parse(SrvConfigPtr cfg, ConstElementPtr subnets_list) {
    size_t cnt = 0;
    BOOST_FOREACH(ConstElementPtr subnet_json, subnets_list->listValue()) {

        Subnet6ConfigParser parser;
        Subnet6Ptr subnet = parser.parse(subnet_json);

        // Adding a subnet to the Configuration Manager may fail if the
        // subnet id is invalid (duplicate). Thus, we catch exceptions
        // here to append a position in the configuration string.
        try {
            cfg->getCfgSubnets6()->add(subnet);
            cnt++;
        } catch (const std::exception& ex) {
            isc_throw(DhcpConfigError, ex.what() << " ("
                      << subnet_json->getPosition() << ")");
        }
    }
    return (cnt);
}


//**************************** D2ClientConfigParser **********************

dhcp_ddns::NameChangeProtocol
D2ClientConfigParser::getProtocol(ConstElementPtr scope,
                                  const std::string& name) {
    return (getAndConvert<dhcp_ddns::NameChangeProtocol,
            dhcp_ddns::stringToNcrProtocol>
            (scope, name, "NameChangeRequest protocol"));
}

dhcp_ddns::NameChangeFormat
D2ClientConfigParser::getFormat(ConstElementPtr scope,
                                const std::string& name) {
    return (getAndConvert<dhcp_ddns::NameChangeFormat,
            dhcp_ddns::stringToNcrFormat>
            (scope, name, "NameChangeRequest format"));
}

D2ClientConfig::ReplaceClientNameMode
D2ClientConfigParser::getMode(ConstElementPtr scope,
                              const std::string& name) {
    return (getAndConvert<D2ClientConfig::ReplaceClientNameMode,
            D2ClientConfig::stringToReplaceClientNameMode>
            (scope, name, "ReplaceClientName mode"));
}

D2ClientConfigPtr
D2ClientConfigParser::parse(isc::data::ConstElementPtr client_config) {
    D2ClientConfigPtr new_config;

    // Get all parameters that are needed to create the D2ClientConfig.
    bool enable_updates = getBoolean(client_config, "enable-updates");

    IOAddress server_ip = getAddress(client_config, "server-ip");

    uint32_t server_port = getUint32(client_config, "server-port");

    std::string sender_ip_str = getString(client_config, "sender-ip");

    uint32_t sender_port = getUint32(client_config, "sender-port"); 

    uint32_t max_queue_size = getUint32(client_config, "max-queue-size"); 

    dhcp_ddns::NameChangeProtocol ncr_protocol =
        getProtocol(client_config, "ncr-protocol");

    dhcp_ddns::NameChangeFormat ncr_format =
        getFormat(client_config, "ncr-format");

    bool always_include_fqdn =
        getBoolean(client_config, "always-include-fqdn");

    bool override_no_update =
        getBoolean(client_config, "override-no-update");

    bool override_client_update =
        getBoolean(client_config, "override-client-update");

    D2ClientConfig::ReplaceClientNameMode replace_client_name_mode =
        getMode(client_config, "replace-client-name");

    std::string generated_prefix =
        getString(client_config, "generated-prefix");

    // qualifying-suffix is the only parameter which has no default
    std::string qualifying_suffix = "";
    bool found_qualifying_suffix = false;
    if (client_config->contains("qualifying-suffix")) {
            qualifying_suffix = getString(client_config, "qualifying-suffix");
            found_qualifying_suffix = true;
    }   

    IOAddress sender_ip(0);
    if (sender_ip_str.empty()) {
        // The default sender IP depends on the server IP family
        sender_ip = (server_ip.isV4() ? IOAddress::IPV4_ZERO_ADDRESS() :
                                        IOAddress::IPV6_ZERO_ADDRESS());
    } else {
        try {
            sender_ip = IOAddress(sender_ip_str);
        } catch (const std::exception& ex) {
            isc_throw(DhcpConfigError, "invalid address (" << sender_ip_str
                      << ") specified for parameter 'sender-ip' ("
                      << getPosition("sender-ip", client_config) << ")");
        }
    }

    // Qualifying-suffix is required when updates are enabled
    if (enable_updates && !found_qualifying_suffix) {
        isc_throw(DhcpConfigError,
                  "parameter 'qualifying-suffix' is required when "
                  "updates are enabled ("
                  << client_config->getPosition() << ")");
    }

    // Now we check for logical errors. This repeats what is done in
    // D2ClientConfig::validate(), but doing it here permits us to
    // emit meaningful parameter position info in the error.
    if (ncr_format != dhcp_ddns::FMT_JSON) {
        isc_throw(D2ClientError, "D2ClientConfig error: NCR Format: "
                  << dhcp_ddns::ncrFormatToString(ncr_format)
                  << " is not supported. ("
                  << getPosition("ncr-format", client_config) << ")");
    }

    if (ncr_protocol != dhcp_ddns::NCR_UDP) {
        isc_throw(D2ClientError, "D2ClientConfig error: NCR Protocol: "
                  << dhcp_ddns::ncrProtocolToString(ncr_protocol)
                  << " is not supported. ("
                  << getPosition("ncr-protocol", client_config) << ")");
    }

    if (sender_ip.getFamily() != server_ip.getFamily()) {
        isc_throw(D2ClientError,
                  "D2ClientConfig error: address family mismatch: "
                  << "server-ip: " << server_ip.toText()
                  << " is: " << (server_ip.isV4() ? "IPv4" : "IPv6")
                  << " while sender-ip: "  << sender_ip.toText()
                  << " is: " << (sender_ip.isV4() ? "IPv4" : "IPv6")
                  << " (" << getPosition("sender-ip", client_config) << ")");
    }

    if (server_ip == sender_ip && server_port == sender_port) {
        isc_throw(D2ClientError,
                  "D2ClientConfig error: server and sender cannot"
                  " share the exact same IP address/port: "
                  << server_ip.toText() << "/" << server_port
                  << " (" << getPosition("sender-ip", client_config) << ")");
    }

    try {
        // Attempt to create the new client config.
        new_config.reset(new D2ClientConfig(enable_updates,
                                            server_ip,
                                            server_port,
                                            sender_ip,
                                            sender_port,
                                            max_queue_size,
                                            ncr_protocol,
                                            ncr_format,
                                            always_include_fqdn,
                                            override_no_update,
                                            override_client_update,
                                            replace_client_name_mode,
                                            generated_prefix,
                                            qualifying_suffix));

    }  catch (const std::exception& ex) {
        isc_throw(DhcpConfigError, ex.what() << " ("
                  << client_config->getPosition() << ")");
    }

    return(new_config);
}

/// @brief This table defines default values for D2 client configuration
const SimpleDefaults D2ClientConfigParser::D2_CLIENT_CONFIG_DEFAULTS = {
    // enable-updates is unconditionally required
    { "server-ip", Element::string, "127.0.0.1" },
    { "server-port", Element::integer, "53001" },
    // default sender-ip depends on server-ip family, so we leave default blank
    // parser knows to use the appropriate ZERO address based on server-ip
    { "sender-ip", Element::string, "" },
    { "sender-port", Element::integer, "0" },
    { "max-queue-size", Element::integer, "1024" },
    { "ncr-protocol", Element::string, "UDP" },
    { "ncr-format", Element::string, "JSON" },
    { "always-include-fqdn", Element::boolean, "false" },
    { "override-no-update", Element::boolean, "false" },
    { "override-client-update", Element::boolean, "false" },
    { "replace-client-name", Element::string, "never" },
    { "generated-prefix", Element::string, "myhost" }
    // qualifying-suffix has no default
};

size_t
D2ClientConfigParser::setAllDefaults(isc::data::ConstElementPtr d2_config) {
    ElementPtr mutable_d2 = boost::const_pointer_cast<Element>(d2_config);
    return (SimpleParser::setDefaults(mutable_d2, D2_CLIENT_CONFIG_DEFAULTS));
}

};  // namespace dhcp
};  // namespace isc