flex_option_callouts.cc

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// Copyright (C) 2019-2026 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 <flex_option.h>
#include <flex_option_log.h>
#include <cc/command_interpreter.h>
#include <hooks/hooks.h>
#include <dhcp/pkt4.h>
#include <dhcp/pkt6.h>
#include <dhcpsrv/cfgmgr.h>
#include <process/daemon.h>
 
namespace isc {
namespace flex_option {
 
FlexOptionImplPtr impl;
 
} // end of namespace flex_option
} // end of namespace isc
 
using namespace isc;
using namespace isc::data;
using namespace isc::dhcp;
using namespace isc::flex_option;
using namespace isc::hooks;
using namespace isc::process;
 
// Functions accessed by the hooks framework use C linkage to avoid the name
// mangling that accompanies use of the C++ compiler as well as to avoid
// issues related to namespaces.
extern "C" {

int pkt4_receive(CalloutHandle& handle) {
    CalloutHandle::CalloutNextStep status = handle.getStatus();
    if ((status == CalloutHandle::NEXT_STEP_SKIP) ||
        (status == CalloutHandle::NEXT_STEP_DROP)) {
        return (0);
    }
 
    // Sanity.
    if (!impl) {
        return (0);
    }
 
    // Get the parameters.
    Pkt4Ptr query;
    handle.getArgument("query4", query);
 
    if (!query) {
        return (0);
    }
 
    try {
        impl->process<Pkt4Ptr>(Option::V4, query, Pkt4Ptr());
    } catch (const std::exception& ex) {
        LOG_ERROR(flex_option_logger, FLEX_OPTION_PROCESS_ERROR)
            .arg(query->getLabel())
            .arg(ex.what());
    }
 
    return (0);
}

int pkt6_receive(CalloutHandle& handle) {
    CalloutHandle::CalloutNextStep status = handle.getStatus();
    if ((status == CalloutHandle::NEXT_STEP_SKIP) ||
        (status == CalloutHandle::NEXT_STEP_DROP)) {
        return (0);
    }
 
    // Sanity.
    if (!impl) {
        return (0);
    }
 
    // Get the parameters.
    Pkt6Ptr query;
    handle.getArgument("query6", query);
 
    if (!query) {
        return (0);
    }
 
    try {
        impl->process<Pkt6Ptr>(Option::V6, query, Pkt6Ptr());
    } catch (const std::exception& ex) {
        LOG_ERROR(flex_option_logger, FLEX_OPTION_PROCESS_ERROR)
            .arg(query->getLabel())
            .arg(ex.what());
    }
 
    return (0);
}

int pkt4_send(CalloutHandle& handle) {
    CalloutHandle::CalloutNextStep status = handle.getStatus();
    if (status == CalloutHandle::NEXT_STEP_DROP) {
        return (0);
    }
 
    // Sanity.
    if (!impl) {
        return (0);
    }
 
    // Get the parameters.
    Pkt4Ptr query;
    Pkt4Ptr response;
    handle.getArgument("query4", query);
    handle.getArgument("response4", response);
 
    if (status == CalloutHandle::NEXT_STEP_SKIP) {
        isc_throw(InvalidOperation, "packet pack already handled");
    }
    if (!query || !response) {
        return (0);
    }
 
    try {
        impl->process<Pkt4Ptr>(Option::V4, query, response);
    } catch (const std::exception& ex) {
        LOG_ERROR(flex_option_logger, FLEX_OPTION_PROCESS_ERROR)
            .arg(query->getLabel())
            .arg(ex.what());
    }
 
    return (0);
}

int pkt6_send(CalloutHandle& handle) {
    CalloutHandle::CalloutNextStep status = handle.getStatus();
    if (status == CalloutHandle::NEXT_STEP_DROP) {
        return (0);
    }
 
    // Sanity.
    if (!impl) {
        return (0);
    }
 
    // Get the parameters.
    Pkt6Ptr query;
    Pkt6Ptr response;
    handle.getArgument("query6", query);
    handle.getArgument("response6", response);
 
    if (status == CalloutHandle::NEXT_STEP_SKIP) {
        isc_throw(InvalidOperation, "packet pack already handled");
    }
    if (!query || !response) {
        return (0);
    }
 
    try {
        impl->process<Pkt6Ptr>(Option::V6, query, response);
    } catch (const std::exception& ex) {
        LOG_ERROR(flex_option_logger, FLEX_OPTION_PROCESS_ERROR)
            .arg(query->getLabel())
            .arg(ex.what());
    }
 
    return (0);
}

int load(LibraryHandle& handle) {
    try {
        // Make the hook library not loadable by d2.
        uint16_t family = CfgMgr::instance().getFamily();
        const std::string& proc_name = Daemon::getProcName();
        if (family == AF_INET) {
            if (proc_name != "kea-dhcp4") {
                isc_throw(isc::Unexpected, "Bad process name: " << proc_name
                          << ", expected kea-dhcp4");
            }
        } else {
            if (proc_name != "kea-dhcp6") {
                isc_throw(isc::Unexpected, "Bad process name: " << proc_name
                          << ", expected kea-dhcp6");
            }
        }
 
        impl.reset(new FlexOptionImpl());
        ConstElementPtr options = handle.getParameter("options");
        impl->configure(options);
    } catch (const std::exception& ex) {
        LOG_ERROR(flex_option_logger, FLEX_OPTION_LOAD_ERROR)
            .arg(ex.what());
        return (1);
    }
 
    return (0);
}

int unload() {
    impl.reset();
    LOG_INFO(flex_option_logger, FLEX_OPTION_UNLOAD);
    return (0);
}

int multi_threading_compatible() {
    return (1);
}
 
} // end extern "C"