// Copyright (C) 2025 Ada Logcis Ltd.

//

// 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 <fuzzer/FuzzedDataProvider.h>

#include <dhcp/dhcp4.h>

#include <dhcp/pkt4.h>

#include <dhcp/libdhcp++.h>

#include <dhcp4/ctrl_dhcp4_srv.h>

#include <dhcpsrv/callout_handle_store.h>

#include <log/logger_support.h>

#include <util/filesystem.h>

#include <cstddef>

#include <cstdint>

#include <vector>

#include <list>

#include <memory>

#include <iostream>

#include <filesystem>

#include <fstream>

#include <string>

#include <cstdio>

#include "helper_func.h"

using namespace isc::dhcp;

using namespace isc::hooks;

using namespace isc::util;

extern "C" int buffer4_receive(CalloutHandle& handle);

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

    if (size < 236) {

        // package size requires at least 236 bytes

        return 0;

    }

    // Initialise logging

    setenv("KEA_LOGGER_DESTINATION", "/dev/null", 0);

    setenv("KEA_LOCKFILE_DIR", "/tmp", 0);

    setenv("KEA_PIDFILE_DIR", "/tmp", 0);

    setenv("KEA_LFC_EXECUTABLE", "/bin/true", 0);

    try {

        isc::log::initLogger("fuzzer");

        isc::process::Daemon::loggerInit("fuzzer", false);

        isc::process::Daemon::setDefaultLoggerName("fuzzer");

    } catch (...) {

        // Early exit if logging initialisation failed

        return 0;

    }

    Pkt4Ptr pkt;

    // Package parsing

    try {

        // Add fixed magic cookie and correct hardware address

        std::vector<uint8_t> buf(data, data + size);

        if (size >= 240) {

            // Max hardware address length is 20

            buf[2] = 20;

            // Magic cookie fixed value 0x63825363

            buf[236] = 0x63;

            buf[237] = 0x82;

            buf[238] = 0x53;

            buf[239] = 0x63;

        }

        pkt = Pkt4Ptr(new Pkt4(buf.data(), buf.size()));

        pkt->unpack();

    } catch (...) {

        // Early exit if package parsing failed.

        return 0;

    }

    // Configure random value in packet

    FuzzedDataProvider fdp(data, size);

    uint8_t typeChoice = fdp.ConsumeIntegralInRange<uint8_t>(0, 8);

    pkt->setType(static_cast<DHCPMessageType>(typeChoice));

    CalloutHandlePtr handle = getCalloutHandle(pkt);

    // Fuzz buffer4_receive

    try {

        handle = getCalloutHandle(pkt);

        handle->setArgument("query4", pkt);

        buffer4_receive(*handle);

    } catch (const isc::Exception& e) {

        // Slient exceptions

    } catch (const boost::exception& e) {

        // Slient exceptions

    }

    // Clean handle to avoid mem leak

    if (handle) {

        handle->deleteAllArguments();

    }

    return 0;

}