Cppcheck report - cppcheck report: premium/src/hooks/dhcp/host_cmds/host_cmds.cc

// Copyright (C) 2017-2024 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Kea Hooks Basic
// Commercial End User License Agreement v2.0. See COPYING file in the premium/
// directory.

#include <config.h>
#include <host_cmds.h><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <config/command_mgr.h>
#include <config/cmds_impl.h>
#include <host_data_parser.h><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <cc/command_interpreter.h>
#include <cc/simple_parser.h>
#include <cc/data.h>
#include <asiolink/io_address.h>
#include <host_cmds_log.h><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <dhcpsrv/cfgmgr.h>
#include <dhcpsrv/host_mgr.h>
#include <dhcpsrv/cfg_hosts.h>
#include <dhcpsrv/cfg_subnets4.h>
#include <dhcpsrv/cfg_subnets6.h>
#include <dhcpsrv/subnet_id.h>
#include <util/encode/encode.h>
#include <util/str.h>
#include <exceptions/exceptions.h>
#include <boost/algorithm/string.hpp><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <boost/foreach.hpp><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <string><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <sstream><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.

using namespace isc::dhcp;
using namespace isc::data;
using namespace isc::config;
using namespace isc::asiolink;
using namespace isc::hooks;
using namespace std;

namespace isc {
namespace host_cmds {

/// @brief Wrapper class around reservation command handlers.
class HostCmdsImpl : private CmdsImpl {
public:

    /// @brief Constructor.
    HostCmdsImpl();

    /// @brief Destructor.
    ~HostCmdsImpl();

    /// @brief Parameters specified for reservation-get and reservation-del
    ///
    /// As both call types (get and delete) need specify which reservation to
    /// act on, they have the same set of parameters. In particular, those
    /// two call types support the following sets of parameters:
    /// - subnet-id, address
    /// - subnet-id, identifier type, identifier value
    ///
    /// This class stores those parameters and is used to pass them around.
    class Parameters {
    public:

        /// @brief Specifies subnet-id
        SubnetID subnet_id;

        /// @brief Specifies if subnet-id is present
        bool has_subnet_id;

        /// @brief Specifies IPv4 or IPv6 address (used when query_by_addr is true)
        IOAddress addr;

        /// @brief Specifies identifier type (usually FLEX_ID, used when
        ///        query_by_addr is false)
        Host::IdentifierType type;

        /// @brief Specifies identifier value (used when query_by_addr is false)
        std::vector<uint8_t> ident;

        /// @brief Specifies parameter types (true = query by address, false =
        ///        query by identifier-type,identifier)
        bool query_by_addr;

        /// @brief Specifies page limit (no default).
        size_t page_limit;

        /// @brief Specifies source index (default 0).
        size_t source_index;

        /// @brief Specifies host identifier (default 0).
        uint64_t host_id;

        /// @brief Specifies host name (default "").
        std::string hostname;

        /// @brief Specifies the target host source (default UNSPECIFIED_SOURCE
        /// which means the default host source is command-related).
        HostMgrOperationTarget operation_target;

        /// @brief Default constructor.
        Parameters()
            : subnet_id(0), has_subnet_id(false), addr("::"),
              type(Host::IdentifierType::IDENT_HWADDR), query_by_addr(true),
              page_limit(0), source_index(0), host_id(0),
              operation_target(HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
        }
    };

public:

    /// @brief reservation-add command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationAddHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// add command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int
    reservationAddHandler(CalloutHandle& handle);

    /// @brief reservation-get command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationGetHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// get command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int
    reservationGetHandler(CalloutHandle& handle);

    /// @brief reservation-get-by-address command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationGetByAddressHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// get command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int reservationGetByAddressHandler(CalloutHandle& handle);

    /// @brief reservation-del command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationDelHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// delete command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int
    reservationDelHandler(CalloutHandle& handle);

    /// @brief reservation-get-all command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationGetAllHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// reservation-get-all command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int
    reservationGetAllHandler(CalloutHandle& handle);

    /// @brief reservation-get-page command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationGetPageHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// reservation-get-page command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int
    reservationGetPageHandler(CalloutHandle& handle);

    /// @brief reservation-get-by-hostname command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationGetByHostnameHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// reservation-get-by-hostname command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int
    reservationGetByHostnameHandler(CalloutHandle& handle);

    /// @brief reservation-get-by-id command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationGetByIdHandler
    ///
    /// @param handle Callout context - which is expected to contain the
    /// reservation-get-by-id command JSON text in the "command" argument
    /// @return 0 upon success, non-zero otherwise
    int
    reservationGetByIdHandler(CalloutHandle& handle);

    /// @brief reservation-update command handler
    ///
    /// Provides the implementation for @ref isc::host_cmds::HostCmds::reservationUpdateHandler.
    ///
    /// @param handle callout context
    ///
    /// @return 0 upon success, non-zero otherwise
    int
    reservationUpdateHandler(CalloutHandle& handle);

private:

    /// @brief Extracts parameters required for reservation-get and reservation-del
    ///
    /// See @ref Parameters class for detailed description of what is expected
    /// in the args structure.
    ///
    /// @param args - arguments passed to command
    /// @return parsed parameters
    /// @throw BadValue if input arguments don't make sense.
    Parameters getParameters(const ConstElementPtr& args);

    /// @brief Extracts parameters required for reservation-get-all
    ///
    /// See @ref Parameters class for detailed description of what is expected
    /// in the args structure.
    ///
    /// @param args - arguments passed to command
    /// @return parsed parameters
    /// @throw BadValue if input arguments don't make sense.
    Parameters getAllParameters(const ConstElementPtr& args);

    /// @brief Extracts parameters required for reservation-get-page
    ///
    /// See @ref Parameters class for detailed description of what is expected
    /// in the args structure.
    ///
    /// @param args - arguments passed to command
    /// @return parsed parameters
    /// @throw BadValue if input arguments don't make sense.
    Parameters getPageParameters(const ConstElementPtr& args);

    /// @brief Extracts parameters required for reservation-get-by-hostname
    ///
    /// See @ref Parameters class for detailed description of what is expected
    /// in the args structure.
    ///
    /// @param args - arguments passed to command
    /// @return parsed parameters
    /// @throw BadValue if input arguments don't make sense.
    Parameters getByHostnameParameters(const ConstElementPtr& args);

    /// @brief Extracts parameters required for reservation-get-by-id
    ///
    /// See @ref Parameters class for detailed description of what is expected
    /// in the args structure.
    ///
    /// @param args - arguments passed to command
    /// @return parsed parameters
    /// @throw BadValue if input arguments don't make sense.
    Parameters getByIdParameters(const ConstElementPtr& args);

    /// @brief Extracts parameters required for reservation-get-by-address
    ///
    /// See @ref Parameters class for detailed description of what is expected
    /// in the args structure.
    ///
    /// @param args - arguments passed to command
    /// @return parsed parameters
    /// @throw BadValue if input arguments don't make sense.
    Parameters getByAddressParameters(const ConstElementPtr& params);

    /// @brief Extract the operation target from the parameters.
    /// @param args - arguments passed to command
    /// @return OperationTarget enum value. The target is unspecified if the
    /// related argument doesn't exist.
    HostMgrOperationTarget getOperationTarget(const ConstElementPtr& args);

    /// @brief Checks if the specified IPv4 subnet exists and the reserved address
    /// belongs to this subnet.
    ///
    /// @param subnet_id Subnet identifier. The value of 0 is allowed in which
    /// case no checks are performed and the function simply returns.
    /// @param address Reserved IPv4 address. If this address is 0 it indicates
    /// that no IPv4 address reservation is made and therefore the address is
    /// not checked against the selected subnet.
    ///
    /// @throw isc::BadValue if the subnet id is specified but the subnet does
    /// not exist or if the specified address does not belong to the subnet.
    void validateHostForSubnet4(SubnetID subnet_id, const IOAddress& address);

    /// @brief Checks if the specified IPv6 subnet exists and the reserved
    /// addresses belong to this subnet.
    ///
    /// @param subnet_id Subnet identifier. The value of 0 is allowed in which
    /// case no checks are performed and the function simply returns.
    /// @param addresses Reserved IPv6 addresses. This vector may be empty
    /// indicating that no IPv6 address reservation is made.
    ///
    /// @throw isc::BadValue if the subnet id is specified but the subnet does
    /// not exist or if any of the specified addresses do not belong to the
    /// subnet.
    void validateHostForSubnet6(SubnetID subnet_id,
                                const std::vector<IOAddress>& addresses);

    /// @brief Checks if the subnet is set in the given IPv4 host and
    /// if not add a hint to the error message or return true when empty.
    ///
    /// @param host The host.
    /// @return false if the entry is valid, true if the entry must be
    /// enforced to global (i.e. invalid empty host).
    /// @throw isc::BadValue if the subnet is not set in the host.
    bool checkHost4(const ConstHostPtr& host);

    /// @brief Checks if the subnet is set in the given IPv6 host and
    /// if not add a hint to the error message or return true when empty.
    ///
    /// @param host The host.
    /// @return false if the entry is valid, true if the entry must be
    /// enforced to global (i.e. invalid empty host).
    /// @throw isc::BadValue if the subnet is not set in the host.
    bool checkHost6(const ConstHostPtr& host);

    /// @brief Convenience pointer used to access database storage
    HostDataSourcePtr db_storage_;

    /// @brief Protocol family (IPv4 or IPv6)
    uint16_t family_;
};

HostCmdsImpl::HostCmdsImpl() {
    // There are two ways we can store host reservations: either in configuration
    // or in DB backends. The prime interface we provide - HostMgr class - does
    // not allow storing hosts if alternate data source (DB backend) is not
    // available. Therefore we need to check both. If available, we will store
    // reservations in SQL data source. If not, we will *one day* be able to
    // update the configuration, but it is not possible yet. Current configuration
    // is retrieved as const pointer. We would need a way to clone current
    // configuration to staging, add a host and then commit the change.
    // We need to think this through as we don't want to go through the whole
    // reconfiguration process when a new host is added.

    // Try to get alternate storage.
    db_storage_ = HostMgr::instance().getHostDataSource();
<--- Variable 'db_storage_' is assigned in constructor body. Consider performing initialization in initialization list. [+]
When an object of a class is created, the constructors of all member variables are called consecutively in the order the variables are declared, even if you don't explicitly write them to the initialization list. You could avoid assigning 'db_storage_' a value by passing the value to the constructor in the initialization list.

    // Try to get the configuration storage. This will come in handy one day.
    // cfg_storage_ = CfgMgr::instance().getCurrentCfg()->getCfgHosts();

    family_ = CfgMgr::instance().getFamily();
}

HostCmdsImpl::~HostCmdsImpl() {
    db_storage_.reset();
}

int
HostCmdsImpl::reservationAddHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    bool force_global(false);
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_ADD)
            .arg(txt);

        if (!cmd_args_) {
            isc_throw(isc::BadValue, "no parameters specified for the command");
        }

        HostMgrOperationTarget operation_target = getOperationTarget(cmd_args_);
        if (operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            operation_target = HostMgrOperationTarget::ALTERNATE_SOURCES;
        }

        ConstElementPtr reservation = cmd_args_->get("reservation");
        if (!reservation) {
            isc_throw(isc::BadValue, "reservation must be specified");
        }

        HostPtr host;
        if (family_ == AF_INET) {
            HostDataParser4 parser;
            host = parser.parseWithSubnet(reservation, false);
            force_global = checkHost4(host);
            if (force_global) {
                host->setIPv4SubnetID(SUBNET_ID_GLOBAL);
            }
        } else {
            HostDataParser6 parser;
            host = parser.parseWithSubnet(reservation, false);
            force_global = checkHost6(host);
            if (force_global) {
                host->setIPv6SubnetID(SUBNET_ID_GLOBAL);
            }
        }

        // If we haven't accessed db_storage_ yet, try to retrieve it.
        if (!db_storage_) {
            db_storage_ = HostMgr::instance().getHostDataSource();
        }

        if (!db_storage_ && operation_target == HostMgrOperationTarget::ALTERNATE_SOURCES) {
            // If it's still not available, bail out.
            isc_throw(isc::BadValue, "Host database not available, cannot add host.");
        }

        if (family_ == AF_INET) {
            // Validate the IPv4 subnet id against configured subnet and also verify
            // that the reserved IPv4 address (if non-zero) belongs to this subnet.
            validateHostForSubnet4(host->getIPv4SubnetID(),
                                   host->getIPv4Reservation());

        } else {
            // Retrieve all reserved addresses from the host. We're going to
            // check if these addresses are in range with the specified subnet.
            // If any of them is not in range, we will reject the command.
            // Note that we do not validate delegated prefixes because they don't
            // have to match the subnet prefix.
            auto const& range = host->getIPv6Reservations(IPv6Resrv::TYPE_NA);
            std::vector<IOAddress> addresses;
            BOOST_FOREACH(auto const& address, range) {
                addresses.push_back(address.second.getPrefix());
            }
            // Validate the IPv6 subnet id against configured subnet and also
            // verify that the reserved IPv6 addresses (if any) belong to this
            // subnet.
            validateHostForSubnet6(host->getIPv6SubnetID(), addresses);
        }

        HostMgr::instance().add(host, operation_target);
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_ADD_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_ADD_SUCCESS)
        .arg(txt);
    string msg("Host added.");
    if (force_global) {
        msg += " subnet-id not specified, assumed global (subnet-id 0).";
    }
    setSuccessResponse(handle, msg);
    return (0);
}

HostCmdsImpl::Parameters
HostCmdsImpl::getParameters(const ConstElementPtr& params) {
    Parameters x;

    if (!params || params->getType() != Element::map) {
        isc_throw(BadValue, "Parameters missing or are not a map.");
    }

    // We support 2 types of reservation-get:
    // reservation-get(subnet-id, address, operation-target)
    // reservation-get(subnet-id, identifier-type, identifier, operation-target)
    ConstElementPtr addr = params->get("ip-address");
    ConstElementPtr type = params->get("identifier-type");
    ConstElementPtr ident = params->get("identifier");
    if (params->contains("subnet-id") || (!addr && !type && !ident)) {
        int64_t value = data::SimpleParser::getInteger(params, "subnet-id",
                                                       0, dhcp::SUBNET_ID_MAX);
        x.subnet_id = static_cast<SubnetID>(value);
        x.has_subnet_id = true;
    } else {
        x.has_subnet_id = false;
    }

    x.operation_target = getOperationTarget(params);

    if (addr) {
        if (addr->getType() != Element::string) {
            isc_throw(BadValue, "'ip-address' is not a string.");
        }

        x.addr = IOAddress(addr->stringValue());
        x.query_by_addr = true;
        if (!x.has_subnet_id) {
            isc_throw(BadValue, "missing parameter 'subnet-id', use "
                      "'reservation-get-by-address' with 'ip-address' set to \""
                      << addr->stringValue() << "\" to get the list of "
                      << "reservations with this address");
        }
        return (x);
    }

    // No address specified. Ok, so it must be identifier based query.
    // "identifier-type": "duid",
    // "identifier": "aa:bb:cc:dd:ee:..."

    if (!type || type->getType() != Element::string) {
        isc_throw(BadValue, "No 'ip-address' provided"
                  " and 'identifier-type' is either missing or not a string.");
    }
    if (!ident || ident->getType() != Element::string) {
        isc_throw(BadValue, "No 'ip-address' provided"
                  " and 'identifier' is either missing or not a string.");
    }

    // Got the parameters. Let's see if their values make sense.

    // Try to parse the identifier value first.
    try {
        x.ident = util::str::quotedStringToBinary(ident->stringValue());
        if (x.ident.empty()) {
            util::str::decodeFormattedHexString(ident->stringValue(),
                                                x.ident);
        }
    } catch (...) {
        // The string doesn't match any known pattern, so we have to
        // report an error at this point.
        isc_throw(BadValue, "Unable to parse 'identifier' value.");
    }

    if (x.ident.empty()) {
        isc_throw(BadValue, "Unable to query for empty 'identifier'.");
    }

    // Next, try to convert identifier-type
    try {
        x.type = Host::getIdentifierType(type->stringValue());
    } catch (const std::exception& ex) {
        isc_throw(BadValue, "Value of 'identifier-type' was not recognized.");
    }

    x.query_by_addr = false;
    if (!x.has_subnet_id) {
        isc_throw(BadValue, "missing parameter 'subnet-id', use "
                  "'reservation-get-by-id' with 'identifier-type' set to \""
                  << type->stringValue() << "\" and 'identifier' to \""
                  << ident->stringValue() << "\" to get the list of "
                  << "reservations with this identifier");
    }
    return (x);
}

void
HostCmdsImpl::validateHostForSubnet4(SubnetID subnet_id, const IOAddress& address) {
    if (subnet_id != 0) {
        auto cfg = CfgMgr::instance().getCurrentCfg()->getCfgSubnets4();
        auto subnet = cfg->getBySubnetId(subnet_id);
        if (!subnet) {
            isc_throw(isc::BadValue,
                      "IPv4 subnet with ID of '" << subnet_id
                      << "' is not configured");
        }

        if (!address.isV4Zero() && !address.isV6Zero()
            && !subnet->inRange(address)) {
            isc_throw(isc::BadValue,
                      "specified reservation '" << address
                      << "' is not matching the IPv4 subnet prefix '"
                      << subnet->toText() << "'");
        }
    }
}

void
HostCmdsImpl::validateHostForSubnet6(SubnetID subnet_id,
                                     const std::vector<IOAddress>& addresses) {
    if (subnet_id != 0) {
        auto cfg = CfgMgr::instance().getCurrentCfg()->getCfgSubnets6();
        auto subnet = cfg->getBySubnetId(subnet_id);
        if (!subnet) {
            isc_throw(isc::BadValue,
                      "IPv6 subnet with ID of '" << subnet_id
                      << "' is not configured");
        }

        for (auto const& address : addresses) {
            if (!subnet->inRange(address)) {
                isc_throw(isc::BadValue,
                          "specified reservation '" << address
                          << "' is not matching the IPv6 subnet prefix '"
                          << subnet->toText() << "'");
            }
        }
    }
}

bool
HostCmdsImpl::checkHost4(const ConstHostPtr& host) {
    if (host->getIPv4SubnetID() != SUBNET_ID_UNUSED) {
        return (false);
    }
    const IOAddress& addr = host->getIPv4Reservation();
    if (!addr.isV4Zero()) {
        // Try to find a subnet hint.
        auto subnets = CfgMgr::instance().getCurrentCfg()->getCfgSubnets4();
        ConstSubnet4Ptr guarded;
        ConstSubnet4Ptr candidate;
        bool others = false;
        for (auto const& subnet : *subnets->getAll()) {
            if (!subnet->inRange(addr)) {
                continue;
            }
            if (subnet->clientSupported(ClientClasses())) {
                if (!candidate) {
                    candidate = subnet;
                } else {
                    others = true;
                }
            } else if (!guarded) {
                guarded = subnet;
            } else {
                others = true;
            }
        }
        if (guarded && candidate) {
            others = true;
        }
        if (!guarded && !candidate) {
            isc_throw(isc::BadValue, "Mandatory 'subnet-id' parameter missing."
                      << " The address '" << addr.toText()
                      << "' belongs to no configured subnet.");
        }
        if (candidate) {
            isc_throw(isc::BadValue, "Mandatory 'subnet-id' parameter missing."
                      << " The address '" << addr.toText()
                      << "' belongs to subnet '" << candidate->toText()
                      << "' id " << candidate->getID()
                      << (others ? " and others." : "."));
        } else {
            isc_throw(isc::BadValue, "Mandatory 'subnet-id' parameter missing."
                      << " The address '" << addr.toText()
                      << "' belongs to guarded subnet '" << guarded->toText()
                      << "' id " << guarded->getID()
                      << (others ? " and others." : "."));
        }
    } else {
        return (true);
    }
}

bool
HostCmdsImpl::checkHost6(const ConstHostPtr& host) {
    if (host->getIPv6SubnetID() != SUBNET_ID_UNUSED) {
        return (false);
    }
    auto const& range = host->getIPv6Reservations();
    std::vector<IOAddress> addresses;
    bool has_prefixes = false;
    BOOST_FOREACH(auto const& address, range) {
        if (address.first == IPv6Resrv::TYPE_NA) {
            addresses.push_back(address.second.getPrefix());
        } else {
            has_prefixes = true;
        }
    }
    if (!addresses.empty()) {
        // Try to find a subnet hint.
        auto subnets = CfgMgr::instance().getCurrentCfg()->getCfgSubnets6();
        ConstSubnet6Ptr guarded;
        ConstSubnet6Ptr candidate;
        bool others = false;
        for (auto const& subnet : *subnets->getAll()) {
            bool in_range = true;
            for (auto const& address : addresses) {
                if (!subnet->inRange(address)) {<--- Consider using std::any_of algorithm instead of a raw loop.
                    in_range = false;
                    break;
                }
            }
            if (!in_range) {
                continue;
            }
            if (subnet->clientSupported(ClientClasses())) {
                if (!candidate) {
                    candidate = subnet;
                } else {
                    others = true;
                }
            } else if (!guarded) {
                guarded = subnet;
            } else {
                others = true;
            }
        }
        if (guarded && candidate) {
            others = true;
        }
        if (!guarded && !candidate) {
            isc_throw(isc::BadValue, "Mandatory 'subnet-id' parameter missing."
                      << " Reserved IPv6 addresses do not belong to a"
                      << " common configured subnet.");
        }
        if (candidate) {
            isc_throw(isc::BadValue, "Mandatory 'subnet-id' parameter missing."
                      << " Reserved IPv6 addresses belong to subnet '"
                      << candidate->toText() << "' id " << candidate->getID()
                      << (others ? " and others." : "."));
        } else {
            isc_throw(isc::BadValue, "Mandatory 'subnet-id' parameter missing."
                      << " Reserved IPv6 addresses belong to guarded subnet '"
                      << guarded->toText() << "' id " << guarded->getID()
                      << (others ? " and others." : "."));
        }
    } else if (has_prefixes) {
        isc_throw(isc::BadValue, "Mandatory 'subnet-id' parameter missing."
                  << " Prefixes are not attached to subnets so no hint is"
                  << " available.");
    } else {
        return (true);
    }
}

int
HostCmdsImpl::reservationGetHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    Parameters p;
    ElementPtr host_json;
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET)
            .arg(txt);

        p = getParameters(cmd_args_);

        if (p.operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            p.operation_target = HostMgrOperationTarget::ALL_SOURCES;
        }

        ConstHostPtr host;
        if (p.query_by_addr) {
            // Query by address
            if (p.addr.isV4()) {
                host = HostMgr::instance().get4(p.subnet_id, p.addr, p.operation_target);
            } else {
                host = HostMgr::instance().get6(p.subnet_id, p.addr, p.operation_target);
            }
        } else {
            // Query by identifier
            if (family_ == AF_INET) {
                host = HostMgr::instance().get4(p.subnet_id, p.type, &p.ident[0],
                                                p.ident.size(), p.operation_target);
            } else {
                host = HostMgr::instance().get6(p.subnet_id, p.type, &p.ident[0],
                                                p.ident.size(), p.operation_target);
            }
        }
        if (host) {
            SubnetID subnet_id;
            if (family_ == AF_INET) {
                host_json = host->toElement4();
                subnet_id = host->getIPv4SubnetID();
            } else {
                host_json = host->toElement6();
                subnet_id = host->getIPv6SubnetID();
            }
            host_json->set("subnet-id", Element::create(subnet_id));
        }
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_GET_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_SUCCESS)
        .arg(txt);

    if (host_json) {
        ConstElementPtr response = createAnswer(CONTROL_RESULT_SUCCESS,
                                                "Host found.", host_json);
        setResponse(handle, response);
    } else {
        setErrorResponse(handle, "Host not found.", CONTROL_RESULT_EMPTY);
    }

    return (0);
}

int
HostCmdsImpl::reservationGetByAddressHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    Parameters p;
    ElementPtr hosts_json = Element::createList();
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_ADDRESS)
            .arg(txt);

        p = getByAddressParameters(cmd_args_);

        if (p.operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            p.operation_target = HostMgrOperationTarget::ALL_SOURCES;
        }

        ConstHostCollection hosts;
        if (p.has_subnet_id) {
            if (family_ == AF_INET) {
                validateHostForSubnet4(p.subnet_id,
                                       IOAddress::IPV4_ZERO_ADDRESS());
                hosts = HostMgr::instance().getAll4(p.subnet_id, p.addr, p.operation_target);
            } else {
                validateHostForSubnet6(p.subnet_id, std::vector<IOAddress>());
                hosts = HostMgr::instance().getAll6(p.subnet_id, p.addr, p.operation_target);
            }
        } else {
            if (family_ == AF_INET) {
                hosts = HostMgr::instance().getAll4(p.addr, p.operation_target);
            } else {
                hosts = HostMgr::instance().getAll6(p.addr, p.operation_target);
            }
        }

        // Add the subnet-id when it was not specified by the command
        // parameters and filter out wrong universe entries.
        SubnetID subnet_id = p.subnet_id;
        ElementPtr host_json;
        for (auto const& host : hosts) {
            if (!p.has_subnet_id) {
                if (family_ == AF_INET) {
                    subnet_id = host->getIPv4SubnetID();
                } else {
                    subnet_id = host->getIPv6SubnetID();
                }

                if (subnet_id == SUBNET_ID_UNUSED) {
                    continue;
                }
            }

            if (family_ == AF_INET) {
                host_json = host->toElement4();
            } else {
                host_json = host->toElement6();
            }

            host_json->set("subnet-id", Element::create(subnet_id));
            hosts_json->add(host_json);
        }
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_ADDRESS_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_ADDRESS_SUCCESS)
        .arg(txt);

    ostringstream msg;
    msg << hosts_json->size()
        << " IPv" << (family_ == AF_INET ? "4" : "6")
        << " host(s) found.";
    ElementPtr result = Element::createMap();
    result->set("hosts", hosts_json);

    ConstElementPtr response = createAnswer(hosts_json->size() > 0 ?
                                                CONTROL_RESULT_SUCCESS :
                                                CONTROL_RESULT_EMPTY,
                                            msg.str(), result);
    setResponse(handle, response);

    return (0);
}

int
HostCmdsImpl::reservationDelHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    Parameters p;
    bool deleted;
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_DEL)
            .arg(txt);

        p = getParameters(cmd_args_);
        if (p.operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            p.operation_target = HostMgrOperationTarget::ALTERNATE_SOURCES;
        }

        if (p.query_by_addr) {
            // try to delete by address
            deleted = HostMgr::instance().del(p.subnet_id, p.addr, p.operation_target);
        } else {
            // try to delete by identifier
            if (family_ == AF_INET) {
                deleted = HostMgr::instance().del4(p.subnet_id, p.type,
                                                   &p.ident[0], p.ident.size(),
                                                   p.operation_target);
            } else {
                deleted = HostMgr::instance().del6(p.subnet_id, p.type,
                                                   &p.ident[0], p.ident.size(),
                                                   p.operation_target);
            }
        }
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_DEL_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_DEL_SUCCESS)
        .arg(txt);

    if (deleted) {
        setSuccessResponse(handle, "Host deleted.");
    } else {
        setErrorResponse(handle, "Host not deleted (not found).",
                         CONTROL_RESULT_EMPTY);
    }

    return (0);
}

HostCmdsImpl::Parameters
HostCmdsImpl::getAllParameters(const ConstElementPtr& params) {
    Parameters x;

    if (!params || params->getType() != Element::map) {
        isc_throw(BadValue, "Parameters missing or are not a map.");
    }

    // We support one type of reservation-get-all(subnet-id)
    int64_t tmp = data::SimpleParser::getInteger(params, "subnet-id",
                                                 0, dhcp::SUBNET_ID_MAX);
    x.subnet_id = static_cast<SubnetID>(tmp);
    x.has_subnet_id = true;

    x.operation_target = getOperationTarget(params);

    return (x);
}

HostCmdsImpl::Parameters
HostCmdsImpl::getPageParameters(const ConstElementPtr& params) {
    Parameters x;

    if (!params || params->getType() != Element::map) {
        isc_throw(BadValue, "Parameters missing or are not a map.");
    }

    int64_t tmp = data::SimpleParser::getInteger(params, "limit", 0,
                                                 numeric_limits<uint32_t>::max());
    x.page_limit = static_cast<size_t>(tmp);

    // subnet-id, source-index and from host-id are optional.
    if (params->contains("subnet-id")) {
        tmp = data::SimpleParser::getInteger(params, "subnet-id",
                                             0, dhcp::SUBNET_ID_MAX);
        x.subnet_id = static_cast<SubnetID>(tmp);
        x.has_subnet_id = true;
    }

    x.source_index = 0;
    if (params->get("source-index")) {
        tmp = data::SimpleParser::getInteger(params, "source-index", 0, 10);
        x.source_index = static_cast<size_t>(tmp);
    }

    x.host_id = 0;
    if (params->get("from")) {
        tmp = data::SimpleParser::getInteger(params, "from");
        x.host_id = static_cast<uint64_t>(tmp);
    }

    return (x);
}

HostCmdsImpl::Parameters
HostCmdsImpl::getByHostnameParameters(const ConstElementPtr& params) {
    Parameters x;

    if (!params || params->getType() != Element::map) {
        isc_throw(BadValue, "Parameters missing or are not a map.");
    }

    string hostname =  data::SimpleParser::getString(params, "hostname");
    x.hostname = hostname;

    // subnet-id is optional.
    if (params->contains("subnet-id")) {
        int64_t tmp = data::SimpleParser::getInteger(params, "subnet-id",
                                                     0, dhcp::SUBNET_ID_MAX);
        x.subnet_id = static_cast<SubnetID>(tmp);
        x.has_subnet_id = true;
    }

    x.operation_target = getOperationTarget(params);

    return (x);
}

HostCmdsImpl::Parameters
HostCmdsImpl::getByIdParameters(const ConstElementPtr& params) {
    Parameters x;

    if (!params || params->getType() != Element::map) {
        isc_throw(BadValue, "Parameters missing or are not a map.");
    }

    ConstElementPtr type = params->get("identifier-type");
    ConstElementPtr ident = params->get("identifier");
    if (!type || type->getType() != Element::string) {
        isc_throw(BadValue, "'identifier-type' is either missing"
                  " or not a string.");
    }
    if (!ident || ident->getType() != Element::string) {
        isc_throw(BadValue, "'identifier' is either missing or not a string.");
    }

    // subnet-id is forbidden.
    if (params->contains("subnet-id")) {
        isc_throw(BadValue, "'subnet-id' is forbidden in reservation-get-by-id");
    }

    // Got the parameters. Let's see if their values make sense.

    // Try to parse the identifier value first.
    try {
        x.ident = util::str::quotedStringToBinary(ident->stringValue());
        if (x.ident.empty()) {
            util::str::decodeFormattedHexString(ident->stringValue(),
                                                x.ident);
        }
    } catch (...) {
        // The string doesn't match any known pattern, so we have to
        // report an error at this point.
        isc_throw(BadValue, "Unable to parse 'identifier' value.");
    }

    if (x.ident.empty()) {
        isc_throw(BadValue, "Unable to query for empty 'identifier'.");
    }

    // Next, try to convert identifier-type
    try {
        x.type = Host::getIdentifierType(type->stringValue());
    } catch (const std::exception& ex) {
        isc_throw(BadValue, "Value of 'identifier-type' was not recognized.");
    }

    x.operation_target = getOperationTarget(params);

    return (x);
}

HostCmdsImpl::Parameters
HostCmdsImpl::getByAddressParameters(const ConstElementPtr& params) {
    Parameters x;

    if (!params || params->getType() != Element::map) {
        isc_throw(BadValue, "Parameters missing or are not a map.");
    }

    // We support 1 type of reservation-get-by-address:
    // reservation-get-by-address(subnet-id, address, operation-target)
    // where subnet-id and operation-target are optional
    IOAddress addr = data::SimpleParser::getAddress(params, "ip-address");
    if (!addr.isV4() && !addr.isV6()) {
        isc_throw(BadValue, "Failed to parse IP address " << addr);
    }

    x.addr = addr;
    x.query_by_addr = true;

    if (params->contains("subnet-id")) {
        int64_t tmp = data::SimpleParser::getInteger(params, "subnet-id",
                                                     0, dhcp::SUBNET_ID_MAX);
        x.subnet_id = static_cast<SubnetID>(tmp);
        x.has_subnet_id = true;
    }

    x.operation_target = getOperationTarget(params);

    return (x);
}

HostMgrOperationTarget
HostCmdsImpl::getOperationTarget(const ConstElementPtr& args) {
    // Operation target is optional.
    if (!args->get("operation-target")) {
        return HostMgrOperationTarget::UNSPECIFIED_SOURCE;
    }

    std::string raw = data::SimpleParser::getString(args, "operation-target");

    if (raw == "memory") {
        return HostMgrOperationTarget::PRIMARY_SOURCE;
    } else if (raw == "database") {
        return HostMgrOperationTarget::ALTERNATE_SOURCES;
    } else if (raw == "all") {
        return HostMgrOperationTarget::ALL_SOURCES;
    } else if (raw == "default") {
        return HostMgrOperationTarget::UNSPECIFIED_SOURCE;
    } else {
        isc_throw(BadValue,
                  "The 'operation-target' value (" << raw
                  << ") is not within expected set: (memory, database, all, "
                  << "default)");
    }
}

int
HostCmdsImpl::reservationGetAllHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    Parameters p;
    ElementPtr hosts_json = Element::createList();
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_ALL)
            .arg(txt);

        p = getAllParameters(cmd_args_);
        if (p.operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            p.operation_target = HostMgrOperationTarget::ALL_SOURCES;
        }

        ConstHostCollection hosts;
        if (family_ == AF_INET) {
            validateHostForSubnet4(p.subnet_id,
                                   IOAddress::IPV4_ZERO_ADDRESS());
            hosts = HostMgr::instance().getAll4(p.subnet_id, p.operation_target);
        } else {
            validateHostForSubnet6(p.subnet_id, std::vector<IOAddress>());
            hosts = HostMgr::instance().getAll6(p.subnet_id, p.operation_target);
        }
        for (auto const& host : hosts) {
            ElementPtr host_json;
            if (family_ == AF_INET) {
                host_json = host->toElement4();
                SubnetID subnet_id = host->getIPv4SubnetID();
                host_json->set("subnet-id", Element::create(subnet_id));
            } else {
                host_json = host->toElement6();
                SubnetID subnet_id = host->getIPv6SubnetID();
                host_json->set("subnet-id", Element::create(subnet_id));
            }
            hosts_json->add(host_json);
        }
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_GET_ALL_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_ALL_SUCCESS)
        .arg(txt);

    ostringstream msg;
    msg << hosts_json->size()
        << " IPv" << (family_ == AF_INET ? "4" : "6")
        << " host(s) found.";
    ElementPtr result = Element::createMap();
    result->set("hosts", hosts_json);

    ConstElementPtr response = createAnswer(hosts_json->size() > 0 ?
                                            CONTROL_RESULT_SUCCESS :
                                            CONTROL_RESULT_EMPTY,
                                            msg.str(), result);
    setResponse(handle, response);

    return (0);
}

int
HostCmdsImpl::reservationGetPageHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    Parameters p;
    size_t idx;
    ElementPtr hosts_json = Element::createList();
    uint64_t last_id(0);
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_PAGE)
            .arg(txt);

        p = getPageParameters(cmd_args_);
        idx = p.source_index;
        HostPageSize page_size(p.page_limit);
        ConstHostCollection hosts;
        if (p.has_subnet_id) {
            if (family_ == AF_INET) {
                validateHostForSubnet4(p.subnet_id,
                                       IOAddress::IPV4_ZERO_ADDRESS());
                hosts = HostMgr::instance().getPage4(p.subnet_id, idx,
                                                     p.host_id, page_size);
            } else {
                validateHostForSubnet6(p.subnet_id, std::vector<IOAddress>());
                hosts = HostMgr::instance().getPage6(p.subnet_id, idx,
                                                     p.host_id, page_size);
            }
        } else {
            if (family_ == AF_INET) {
                hosts = HostMgr::instance().getPage4(idx, p.host_id, page_size);
            } else {
                hosts = HostMgr::instance().getPage6(idx, p.host_id, page_size);
            }
        }
        SubnetID subnet_id = p.subnet_id;
        ElementPtr host_json;
        for (auto const& host : hosts) {
            if (!p.has_subnet_id) {
                if (family_ == AF_INET) {
                    subnet_id = host->getIPv4SubnetID();
                } else {
                    subnet_id = host->getIPv6SubnetID();
                }
                if (subnet_id == SUBNET_ID_UNUSED) {
                    continue;
                }
            }
            if (family_ == AF_INET) {
                host_json = host->toElement4();
            } else {
                host_json = host->toElement6();
            }
            host_json->set("subnet-id", Element::create(subnet_id));
            hosts_json->add(host_json);
            last_id = host->getHostId();
        }
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_GET_PAGE_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_PAGE_SUCCESS)
        .arg(txt);

    ostringstream msg;
    msg << hosts_json->size()
        << " IPv" << (family_ == AF_INET ? "4" : "6")
        << " host(s) found.";
    ElementPtr result = Element::createMap();
    result->set("hosts", hosts_json);
    result->set("count",
                Element::create(static_cast<int64_t>(hosts_json->size())));
    if (hosts_json->size() > 0) {
        ElementPtr next = Element::createMap();
        next->set("source-index",
                  Element::create(static_cast<int64_t>(idx)));
        next->set("from", Element::create(static_cast<int64_t>(last_id)));
        result->set("next", next);
    }

    ConstElementPtr response = createAnswer(hosts_json->size() > 0 ?
                                            CONTROL_RESULT_SUCCESS :
                                            CONTROL_RESULT_EMPTY,
                                            msg.str(), result);
    setResponse(handle, response);

    return (0);
}

int
HostCmdsImpl::reservationGetByHostnameHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    Parameters p;
    ElementPtr hosts_json = Element::createList();
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_HOSTNAME)
            .arg(txt);

        p = getByHostnameParameters(cmd_args_);
        if (p.operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            p.operation_target = HostMgrOperationTarget::ALL_SOURCES;
        }

        string hostname = p.hostname;
        if (hostname.empty()) {
            isc_throw(isc::BadValue, "Empty hostname");
        }
        boost::algorithm::to_lower(hostname);
        ConstHostCollection hosts;
        if (p.has_subnet_id) {
            if (family_ == AF_INET) {
                validateHostForSubnet4(p.subnet_id,
                                       IOAddress::IPV4_ZERO_ADDRESS());
                hosts = HostMgr::instance().getAllbyHostname4(hostname,
                                                              p.subnet_id,
                                                              p.operation_target);
            } else {
                validateHostForSubnet6(p.subnet_id, std::vector<IOAddress>());
                hosts = HostMgr::instance().getAllbyHostname6(hostname,
                                                              p.subnet_id,
                                                              p.operation_target);
            }
        } else {
            hosts = HostMgr::instance().getAllbyHostname(hostname, p.operation_target);
        }

        // Add the subnet-id when it was not specified by the command
        // parameters and filter out wrong universe entries.
        SubnetID subnet_id = p.subnet_id;
        ElementPtr host_json;
        for (auto const& host : hosts) {
            if (!p.has_subnet_id) {
                if (family_ == AF_INET) {
                    subnet_id = host->getIPv4SubnetID();
                } else {
                    subnet_id = host->getIPv6SubnetID();
                }
                if (subnet_id == SUBNET_ID_UNUSED) {
                    continue;
                }
            }
            if (family_ == AF_INET) {
                host_json = host->toElement4();
            } else {
                host_json = host->toElement6();
            }
            host_json->set("subnet-id", Element::create(subnet_id));
            hosts_json->add(host_json);
        }
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_HOSTNAME_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_HOSTNAME_SUCCESS)
        .arg(txt);

    ostringstream msg;
    msg << hosts_json->size()
        << " IPv" << (family_ == AF_INET ? "4" : "6")
        << " host(s) found.";
    ElementPtr result = Element::createMap();
    result->set("hosts", hosts_json);

    ConstElementPtr response = createAnswer(hosts_json->size() > 0 ?
                                            CONTROL_RESULT_SUCCESS :
                                            CONTROL_RESULT_EMPTY,
                                            msg.str(), result);
    setResponse(handle, response);

    return (0);
}

int
HostCmdsImpl::reservationGetByIdHandler(CalloutHandle& handle) {
    string txt = "(missing parameters)";
    Parameters p;
    ElementPtr hosts_json = Element::createList();
    try {
        extractCommand(handle);
        if (cmd_args_) {
            txt = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_ID)
            .arg(txt);

        p = getByIdParameters(cmd_args_);
        if (p.operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            p.operation_target = HostMgrOperationTarget::ALL_SOURCES;
        }

        ConstHostCollection hosts;
        hosts = HostMgr::instance().getAll(p.type, &p.ident[0], p.ident.size(),
                                           p.operation_target);
        SubnetID subnet_id;
        ElementPtr host_json;
        for (auto const& host : hosts) {
            if (family_ == AF_INET) {
                subnet_id = host->getIPv4SubnetID();
            } else {
                subnet_id = host->getIPv6SubnetID();
            }
            if (subnet_id == SUBNET_ID_UNUSED) {
                continue;
            }
            if (family_ == AF_INET) {
                host_json = host->toElement4();
            } else {
                host_json = host->toElement6();
            }
            host_json->set("subnet-id", Element::create(subnet_id));
            hosts_json->add(host_json);
        }
    } catch (const std::exception& ex) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_ID_FAILED)
            .arg(txt)
            .arg(ex.what());
        setErrorResponse(handle, ex.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_GET_BY_ID_SUCCESS)
        .arg(txt);

    ostringstream msg;
    msg << hosts_json->size()
        << " IPv" << (family_ == AF_INET ? "4" : "6")
        << " host(s) found.";
    ElementPtr result = Element::createMap();
    result->set("hosts", hosts_json);

    ConstElementPtr response = createAnswer(hosts_json->size() > 0 ?
                                            CONTROL_RESULT_SUCCESS :
                                            CONTROL_RESULT_EMPTY,
                                            msg.str(), result);
    setResponse(handle, response);

    return (0);
}

int
HostCmdsImpl::reservationUpdateHandler(CalloutHandle& handle) {
    string parameters("(missing parameters)");
    try {
        // Basic command extraction
        extractCommand(handle);
        if (cmd_args_) {
            parameters = cmd_args_->str();
        }

        LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_UPDATE)
            .arg(parameters);

        // Sanity checks
        if (!cmd_args_) {
            isc_throw(BadValue,
                      "invalid command: does not contain mandatory '" << CONTROL_ARGUMENTS << "'");
        }
        if (cmd_args_->getType() != Element::map) {
            isc_throw(BadValue, "invalid command: expected '"
                      << CONTROL_ARGUMENTS << "' to be a map, got "
                      << Element::typeToName(cmd_args_->getType()) << " instead");
        }
        ConstElementPtr const reservation(cmd_args_->get("reservation"));
        if (!reservation) {
            isc_throw(BadValue, "invalid command: expected 'reservation' as the sole parameter "
                      "inside the 'arguments' map, didn't get it instead");
        }
        if (reservation->getType() != Element::map) {
            isc_throw(BadValue, "invalid command: expected 'reservation' to be a map, got "
                      << Element::typeToName(reservation->getType()) << " instead");
        }

        HostMgrOperationTarget operation_target = getOperationTarget(cmd_args_);
        if (operation_target == HostMgrOperationTarget::UNSPECIFIED_SOURCE) {
            operation_target = HostMgrOperationTarget::ALTERNATE_SOURCES;
        }

        // Parse host-specific parameters.
        HostPtr host;
        if (family_ == AF_INET) {
            HostDataParser4 parser;
            host = parser.parseWithSubnet(reservation);
        } else {
            HostDataParser6 parser;
            host = parser.parseWithSubnet(reservation);
        }

        // If db_storage_ was not accessed yet, try to retrieve it.
        if (!db_storage_) {
            db_storage_ = HostMgr::instance().getHostDataSource();
        }

        if (!db_storage_ && operation_target == HostMgrOperationTarget::ALTERNATE_SOURCES) {
            // If it's still not available, bail out.
            isc_throw(BadValue, "host database not available, cannot update host");
        }

        if (family_ == AF_INET) {
            // Validate the IPv4 subnet id against configured subnet and also verify
            // that the reserved IPv4 address (if non-zero) belongs to this subnet.
            validateHostForSubnet4(host->getIPv4SubnetID(),
                                   host->getIPv4Reservation());

        } else {
            // Retrieve all reserved addresses from the host. We're going to
            // check if these addresses are in range with the specified subnet.
            // If any of them is not in range, we will reject the command.
            // Note that we do not validate delegated prefixes because they don't
            // have to match the subnet prefix.
            auto const& range = host->getIPv6Reservations(IPv6Resrv::TYPE_NA);
            std::vector<IOAddress> addresses;
            BOOST_FOREACH(auto const& address, range) {
                addresses.push_back(address.second.getPrefix());
            }
            // Validate the IPv6 subnet id against configured subnet and also
            // verify that the reserved IPv6 addresses (if any) belong to this
            // subnet.
            validateHostForSubnet6(host->getIPv6SubnetID(), addresses);
        }

        // Do the update.
        HostMgr::instance().update(host, operation_target);
    } catch (exception const& exception) {
        LOG_ERROR(host_cmds_logger, HOST_CMDS_RESERV_UPDATE_FAILED)
            .arg(parameters)
            .arg(exception.what());
        setErrorResponse(handle, exception.what());
        return (1);
    }

    LOG_INFO(host_cmds_logger, HOST_CMDS_RESERV_UPDATE_SUCCESS).arg(parameters);
    setSuccessResponse(handle, "Host updated.");

    return (0);
}

HostCmds::HostCmds()
    :impl_(new HostCmdsImpl()) {
}

int
HostCmds::reservationAddHandler(CalloutHandle& handle) {
    return (impl_->reservationAddHandler(handle));
}

int
HostCmds::reservationGetHandler(CalloutHandle& handle) {
    return (impl_->reservationGetHandler(handle));
}

int
HostCmds::reservationDelHandler(CalloutHandle& handle) {
    return (impl_->reservationDelHandler(handle));
}

int
HostCmds::reservationGetAllHandler(CalloutHandle& handle) {
    return (impl_->reservationGetAllHandler(handle));
}

int
HostCmds::reservationGetPageHandler(CalloutHandle& handle) {
    return (impl_->reservationGetPageHandler(handle));
}

int
HostCmds::reservationGetByHostnameHandler(CalloutHandle& handle) {
    return (impl_->reservationGetByHostnameHandler(handle));
}

int
HostCmds::reservationGetByIdHandler(CalloutHandle& handle) {
    return (impl_->reservationGetByIdHandler(handle));
}

int
HostCmds::reservationUpdateHandler(CalloutHandle& handle) {
    return (impl_->reservationUpdateHandler(handle));
}

int
HostCmds::reservationGetByAddressHandler(CalloutHandle& handle) {
    return (impl_->reservationGetByAddressHandler(handle));
}

}  // namespace host_cmds
}  // namespace isc