/* $Id: DHCPServerImpl.cpp 79610 2019-07-08 23:29:30Z vboxsync $ */
/** @file
 * VirtualBox COM class implementation
 */

/*
 * Copyright (C) 2006-2019 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 */

#define LOG_GROUP LOG_GROUP_MAIN_DHCPSERVER
#include "NetworkServiceRunner.h"
#include "DHCPServerImpl.h"
#include "AutoCaller.h"
#include "LoggingNew.h"

#include <iprt/asm.h>
#include <iprt/file.h>
#include <iprt/net.h>
#include <iprt/path.h>
#include <iprt/cpp/path.h>
#include <iprt/cpp/utils.h>
#include <iprt/cpp/xml.h>

#include <VBox/com/array.h>
#include <VBox/settings.h>

#include "VirtualBoxImpl.h"

// constructor / destructor
/////////////////////////////////////////////////////////////////////////////
/** @todo Convert to C strings as this is wastefull:    */
const std::string DHCPServerRunner::kDsrKeyGateway = "--gateway";
const std::string DHCPServerRunner::kDsrKeyLowerIp = "--lower-ip";
const std::string DHCPServerRunner::kDsrKeyUpperIp = "--upper-ip";
const std::string DHCPServerRunner::kDsrKeyConfig  = "--config";
const std::string DHCPServerRunner::kDsrKeyComment = "--comment";


struct DHCPServer::Data
{
    Data()
        : enabled(FALSE)
        , router(false)
    {
        tempConfigFileName[0] = '\0';
    }

    Utf8Str IPAddress;
    Utf8Str lowerIP;
    Utf8Str upperIP;

    BOOL enabled;
    bool router;
    DHCPServerRunner dhcp;

    settings::DhcpOptionMap GlobalDhcpOptions;
    settings::VmSlot2OptionsMap VmSlot2Options;

    char tempConfigFileName[RTPATH_MAX];
    com::Utf8Str strLeaseFilename;
    com::Utf8Str networkName;
    com::Utf8Str trunkName;
    com::Utf8Str trunkType;
};


DHCPServer::DHCPServer()
  : m(NULL)
  , mVirtualBox(NULL)
{
    m = new DHCPServer::Data();
}


DHCPServer::~DHCPServer()
{
    if (m)
    {
        delete m;
        m = NULL;
    }
}


HRESULT DHCPServer::FinalConstruct()
{
    return BaseFinalConstruct();
}


void DHCPServer::FinalRelease()
{
    uninit ();

    BaseFinalRelease();
}


void DHCPServer::uninit()
{
    /* Enclose the state transition Ready->InUninit->NotReady */
    AutoUninitSpan autoUninitSpan(this);
    if (autoUninitSpan.uninitDone())
        return;

    if (m->dhcp.isRunning())
        stop();

    unconst(mVirtualBox) = NULL;
}


HRESULT DHCPServer::init(VirtualBox *aVirtualBox, const Utf8Str &aName)
{
    AssertReturn(!aName.isEmpty(), E_INVALIDARG);

    AutoInitSpan autoInitSpan(this);
    AssertReturn(autoInitSpan.isOk(), E_FAIL);

    /* share VirtualBox weakly (parent remains NULL so far) */
    unconst(mVirtualBox) = aVirtualBox;

    unconst(mName) = aName;
    m->IPAddress = "0.0.0.0";
    m->GlobalDhcpOptions[DhcpOpt_SubnetMask] = settings::DhcpOptValue("0.0.0.0");
    m->enabled = FALSE;

    m->lowerIP = "0.0.0.0";
    m->upperIP = "0.0.0.0";

    /* Confirm a successful initialization */
    autoInitSpan.setSucceeded();

    return S_OK;
}


HRESULT DHCPServer::init(VirtualBox *aVirtualBox,
                         const settings::DHCPServer &data)
{
    /* Enclose the state transition NotReady->InInit->Ready */
    AutoInitSpan autoInitSpan(this);
    AssertReturn(autoInitSpan.isOk(), E_FAIL);

    /* share VirtualBox weakly (parent remains NULL so far) */
    unconst(mVirtualBox) = aVirtualBox;

    unconst(mName) = data.strNetworkName;
    m->IPAddress = data.strIPAddress;
    m->enabled = data.fEnabled;
    m->lowerIP = data.strIPLower;
    m->upperIP = data.strIPUpper;

    m->GlobalDhcpOptions.clear();
    m->GlobalDhcpOptions.insert(data.GlobalDhcpOptions.begin(),
                               data.GlobalDhcpOptions.end());

    m->VmSlot2Options.clear();
    m->VmSlot2Options.insert(data.VmSlot2OptionsM.begin(),
                            data.VmSlot2OptionsM.end());

    autoInitSpan.setSucceeded();

    return S_OK;
}


HRESULT DHCPServer::i_saveSettings(settings::DHCPServer &data)
{
    AutoCaller autoCaller(this);
    if (FAILED(autoCaller.rc())) return autoCaller.rc();

    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);

    data.strNetworkName = mName;
    data.strIPAddress = m->IPAddress;

    data.fEnabled = !!m->enabled;
    data.strIPLower = m->lowerIP;
    data.strIPUpper = m->upperIP;

    data.GlobalDhcpOptions.clear();
    data.GlobalDhcpOptions.insert(m->GlobalDhcpOptions.begin(),
                                  m->GlobalDhcpOptions.end());

    data.VmSlot2OptionsM.clear();
    data.VmSlot2OptionsM.insert(m->VmSlot2Options.begin(),
                                m->VmSlot2Options.end());

    return S_OK;
}


HRESULT DHCPServer::getNetworkName(com::Utf8Str &aName)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);

    aName = mName;
    return S_OK;
}


HRESULT DHCPServer::getEnabled(BOOL *aEnabled)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);

    *aEnabled = m->enabled;
    return S_OK;
}


HRESULT DHCPServer::setEnabled(BOOL aEnabled)
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
    m->enabled = aEnabled;

    // save the global settings; for that we should hold only the VirtualBox lock
    alock.release();
    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    HRESULT rc = mVirtualBox->i_saveSettings();

    return rc;
}


HRESULT DHCPServer::getIPAddress(com::Utf8Str &aIPAddress)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);

    aIPAddress = Utf8Str(m->IPAddress);
    return S_OK;
}


HRESULT DHCPServer::getNetworkMask(com::Utf8Str &aNetworkMask)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);

    aNetworkMask = m->GlobalDhcpOptions[DhcpOpt_SubnetMask].text;
    return S_OK;
}


HRESULT DHCPServer::getLowerIP(com::Utf8Str &aIPAddress)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);

    aIPAddress = Utf8Str(m->lowerIP);
    return S_OK;
}


HRESULT DHCPServer::getUpperIP(com::Utf8Str &aIPAddress)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);

    aIPAddress = Utf8Str(m->upperIP);
    return S_OK;
}


HRESULT DHCPServer::setConfiguration(const com::Utf8Str &aIPAddress,
                                     const com::Utf8Str &aNetworkMask,
                                     const com::Utf8Str &aLowerIP,
                                     const com::Utf8Str &aUpperIP)
{
    RTNETADDRIPV4 IPAddress, NetworkMask, LowerIP, UpperIP;

    int vrc = RTNetStrToIPv4Addr(aIPAddress.c_str(), &IPAddress);
    if (RT_FAILURE(vrc))
        return mVirtualBox->setErrorBoth(E_INVALIDARG, vrc, "Invalid server address");

    vrc = RTNetStrToIPv4Addr(aNetworkMask.c_str(), &NetworkMask);
    if (RT_FAILURE(vrc))
        return mVirtualBox->setErrorBoth(E_INVALIDARG, vrc, "Invalid netmask");

    vrc = RTNetStrToIPv4Addr(aLowerIP.c_str(), &LowerIP);
    if (RT_FAILURE(vrc))
        return mVirtualBox->setErrorBoth(E_INVALIDARG, vrc, "Invalid range lower address");

    vrc = RTNetStrToIPv4Addr(aUpperIP.c_str(), &UpperIP);
    if (RT_FAILURE(vrc))
        return mVirtualBox->setErrorBoth(E_INVALIDARG, vrc, "Invalid range upper address");

    /*
     * Insist on continuous mask.  May be also accept prefix length
     * here or address/prefix for aIPAddress?
     */
    vrc = RTNetMaskToPrefixIPv4(&NetworkMask, NULL);
    if (RT_FAILURE(vrc))
        return mVirtualBox->setErrorBoth(E_INVALIDARG, vrc, "Invalid netmask");

    /* It's more convenient to convert to host order once */
    IPAddress.u = RT_N2H_U32(IPAddress.u);
    NetworkMask.u = RT_N2H_U32(NetworkMask.u);
    LowerIP.u = RT_N2H_U32(LowerIP.u);
    UpperIP.u = RT_N2H_U32(UpperIP.u);

    /*
     * Addresses must be unicast and from the same network
     */
    if (   (IPAddress.u & UINT32_C(0xe0000000)) == UINT32_C(0xe0000000)
        || (IPAddress.u & ~NetworkMask.u) == 0
        || ((IPAddress.u & ~NetworkMask.u) | NetworkMask.u) == UINT32_C(0xffffffff))
        return mVirtualBox->setError(E_INVALIDARG, "Invalid server address");

    if (   (LowerIP.u & UINT32_C(0xe0000000)) == UINT32_C(0xe0000000)
        || (LowerIP.u & NetworkMask.u) != (IPAddress.u &NetworkMask.u)
        || (LowerIP.u & ~NetworkMask.u) == 0
        || ((LowerIP.u & ~NetworkMask.u) | NetworkMask.u) == UINT32_C(0xffffffff))
        return mVirtualBox->setError(E_INVALIDARG, "Invalid range lower address");

    if (   (UpperIP.u & UINT32_C(0xe0000000)) == UINT32_C(0xe0000000)
        || (UpperIP.u & NetworkMask.u) != (IPAddress.u &NetworkMask.u)
        || (UpperIP.u & ~NetworkMask.u) == 0
        || ((UpperIP.u & ~NetworkMask.u) | NetworkMask.u) == UINT32_C(0xffffffff))
        return mVirtualBox->setError(E_INVALIDARG, "Invalid range upper address");

    /* The range should be valid ... */
    if (LowerIP.u > UpperIP.u)
        return mVirtualBox->setError(E_INVALIDARG, "Invalid range bounds");

    /* ... and shouldn't contain the server's address */
    if (LowerIP.u <= IPAddress.u && IPAddress.u <= UpperIP.u)
        return mVirtualBox->setError(E_INVALIDARG, "Server address within range bounds");

    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
    m->IPAddress = aIPAddress;
    m->GlobalDhcpOptions[DhcpOpt_SubnetMask] = aNetworkMask;

    m->lowerIP = aLowerIP;
    m->upperIP = aUpperIP;

    // save the global settings; for that we should hold only the VirtualBox lock
    alock.release();
    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    return mVirtualBox->i_saveSettings();
}


HRESULT DHCPServer::encodeOption(com::Utf8Str &aEncoded,
                                 uint32_t aOptCode,
                                 const settings::DhcpOptValue &aOptValue)
{
    switch (aOptValue.encoding)
    {
        case DhcpOptEncoding_Legacy:
        {
            /*
             * This is original encoding which assumed that for each
             * option we know its format and so we know how option
             * "value" text is to be interpreted.
             *
             *   "2:10800"           # integer 32
             *   "6:1.2.3.4 8.8.8.8" # array of ip-address
             */
            aEncoded = Utf8StrFmt("%d:%s", aOptCode, aOptValue.text.c_str());
            break;
        }

        case DhcpOptEncoding_Hex:
        {
            /*
             * This is a bypass for any option - preformatted value as
             * hex string with no semantic involved in formatting the
             * value for the DHCP reply.
             *
             *   234=68:65:6c:6c:6f:2c:20:77:6f:72:6c:64
             */
            aEncoded = Utf8StrFmt("%d=%s", aOptCode, aOptValue.text.c_str());
            break;
        }

        default:
        {
            /*
             * Try to be forward compatible.
             *
             *   "254@42=i hope you know what this means"
             */
            aEncoded = Utf8StrFmt("%d@%d=%s", aOptCode, (int)aOptValue.encoding,
                                  aOptValue.text.c_str());
            break;
        }
    }

    return S_OK;
}


int DHCPServer::addOption(settings::DhcpOptionMap &aMap,
                          DhcpOpt_T aOption, const com::Utf8Str &aValue)
{
    settings::DhcpOptValue OptValue;

    if (aOption != 0)
    {
        OptValue = settings::DhcpOptValue(aValue, DhcpOptEncoding_Legacy);
    }
    /*
     * This is a kludge to sneak in option encoding information
     * through existing API.  We use option 0 and supply the real
     * option/value in the same format that encodeOption() above
     * produces for getter methods.
     */
    else
    {
        uint8_t u8Code;
        char    *pszNext;
        int vrc = RTStrToUInt8Ex(aValue.c_str(), &pszNext, 10, &u8Code);
        if (!RT_SUCCESS(vrc))
            return VERR_PARSE_ERROR;

        uint32_t u32Enc;
        switch (*pszNext)
        {
            case ':':           /* support legacy format too */
            {
                u32Enc = DhcpOptEncoding_Legacy;
                break;
            }

            case '=':
            {
                u32Enc = DhcpOptEncoding_Hex;
                break;
            }

            case '@':
            {
                vrc = RTStrToUInt32Ex(pszNext + 1, &pszNext, 10, &u32Enc);
                if (!RT_SUCCESS(vrc))
                    return VERR_PARSE_ERROR;
                if (*pszNext != '=')
                    return VERR_PARSE_ERROR;
                break;
            }

            default:
                return VERR_PARSE_ERROR;
        }

        aOption = (DhcpOpt_T)u8Code;
        OptValue = settings::DhcpOptValue(pszNext + 1, (DhcpOptEncoding_T)u32Enc);
    }

    aMap[aOption] = OptValue;
    return VINF_SUCCESS;
}


HRESULT DHCPServer::addGlobalOption(DhcpOpt_T aOption, const com::Utf8Str &aValue)
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);

    int rc = addOption(m->GlobalDhcpOptions, aOption, aValue);
    if (!RT_SUCCESS(rc))
        return E_INVALIDARG;

    /* Indirect way to understand that we're on NAT network */
    if (aOption == DhcpOpt_Router)
    {
        m->router = true;
    }

    alock.release();

    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    return mVirtualBox->i_saveSettings();
}


HRESULT DHCPServer::removeGlobalOption(DhcpOpt_T aOption)
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);

    settings::DhcpOptionMap::size_type cErased = m->GlobalDhcpOptions.erase(aOption);
    if (!cErased)
        return E_INVALIDARG;

    alock.release();

    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    return mVirtualBox->i_saveSettings();
}


HRESULT DHCPServer::removeGlobalOptions()
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
    m->GlobalDhcpOptions.clear();

    alock.release();

    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    return mVirtualBox->i_saveSettings();
}


HRESULT DHCPServer::getGlobalOptions(std::vector<com::Utf8Str> &aValues)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
    aValues.resize(m->GlobalDhcpOptions.size());
    settings::DhcpOptionMap::const_iterator it;
    size_t i = 0;
    for (it = m->GlobalDhcpOptions.begin(); it != m->GlobalDhcpOptions.end(); ++it, ++i)
    {
        uint32_t OptCode = (*it).first;
        const settings::DhcpOptValue &OptValue = (*it).second;

        encodeOption(aValues[i], OptCode, OptValue);
    }

    return S_OK;
}

HRESULT DHCPServer::getVmConfigs(std::vector<com::Utf8Str> &aValues)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
    aValues.resize(m->VmSlot2Options.size());
    settings::VmSlot2OptionsMap::const_iterator it;
    size_t i = 0;
    for (it = m->VmSlot2Options.begin(); it != m->VmSlot2Options.end(); ++it, ++i)
    {
        aValues[i] = Utf8StrFmt("[%s]:%d", it->first.VmName.c_str(), it->first.Slot);
    }

    return S_OK;
}


HRESULT DHCPServer::addVmSlotOption(const com::Utf8Str &aVmName,
                                    LONG aSlot,
                                    DhcpOpt_T aOption,
                                    const com::Utf8Str &aValue)
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);

    settings::DhcpOptionMap &map = m->VmSlot2Options[settings::VmNameSlotKey(aVmName, aSlot)];
    int rc = addOption(map, aOption, aValue);
    if (!RT_SUCCESS(rc))
        return E_INVALIDARG;

    alock.release();

    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    return mVirtualBox->i_saveSettings();
}


HRESULT DHCPServer::removeVmSlotOption(const com::Utf8Str &aVmName, LONG aSlot, DhcpOpt_T aOption)
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
    settings::DhcpOptionMap &map = i_findOptMapByVmNameSlot(aVmName, aSlot);
    settings::DhcpOptionMap::size_type cErased = map.erase(aOption);
    if (!cErased)
        return E_INVALIDARG;

    alock.release();

    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    return mVirtualBox->i_saveSettings();
}


HRESULT DHCPServer::removeVmSlotOptions(const com::Utf8Str &aVmName, LONG aSlot)
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
    settings::DhcpOptionMap &map = i_findOptMapByVmNameSlot(aVmName, aSlot);
    map.clear();

    alock.release();

    AutoWriteLock vboxLock(mVirtualBox COMMA_LOCKVAL_SRC_POS);
    return mVirtualBox->i_saveSettings();
}

/**
 * this is mapping (vm, slot)
 */
HRESULT DHCPServer::getVmSlotOptions(const com::Utf8Str &aVmName,
                                     LONG aSlot,
                                     std::vector<com::Utf8Str> &aValues)
{

    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
    settings::DhcpOptionMap &map = i_findOptMapByVmNameSlot(aVmName, aSlot);
    aValues.resize(map.size());
    size_t i = 0;
    settings::DhcpOptionMap::const_iterator it;
    for (it = map.begin(); it != map.end(); ++it, ++i)
    {
        uint32_t OptCode = (*it).first;
        const settings::DhcpOptValue &OptValue = (*it).second;

        encodeOption(aValues[i], OptCode, OptValue);
    }

    return S_OK;
}


HRESULT DHCPServer::getMacOptions(const com::Utf8Str &aMAC, std::vector<com::Utf8Str> &aOption)
{
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
    HRESULT hrc = S_OK;
    ComPtr<IMachine> machine;
    ComPtr<INetworkAdapter> nic;
    settings::VmSlot2OptionsIterator it;
    for(it = m->VmSlot2Options.begin(); it != m->VmSlot2Options.end(); ++it)
    {
        alock.release();
        hrc = mVirtualBox->FindMachine(Bstr(it->first.VmName).raw(), machine.asOutParam());
        alock.acquire();

        if (FAILED(hrc))
            continue;

        alock.release();
        hrc = machine->GetNetworkAdapter(it->first.Slot, nic.asOutParam());
        alock.acquire();

        if (FAILED(hrc))
            continue;

        com::Bstr mac;

        alock.release();
        hrc = nic->COMGETTER(MACAddress)(mac.asOutParam());
        alock.acquire();

        if (FAILED(hrc)) /* no MAC address ??? */
            break;
        if (!RTStrICmp(com::Utf8Str(mac).c_str(), aMAC.c_str()))
            return getVmSlotOptions(it->first.VmName,
                                    it->first.Slot,
                                    aOption);
    } /* end of for */

    return hrc;
}

HRESULT DHCPServer::getEventSource(ComPtr<IEventSource> &aEventSource)
{
    NOREF(aEventSource);
    ReturnComNotImplemented();
}


DECLINLINE(void) addOptionChild(xml::ElementNode *pParent, uint32_t OptCode, const settings::DhcpOptValue &OptValue)
{
    xml::ElementNode *pOption = pParent->createChild("Option");
    pOption->setAttribute("name", OptCode);
    pOption->setAttribute("encoding", OptValue.encoding);
    pOption->setAttribute("value", OptValue.text.c_str());
}


HRESULT DHCPServer::restart()
{
    if (!m->dhcp.isRunning())
        return setErrorBoth(E_FAIL, VERR_PROCESS_NOT_FOUND, tr("not running"));

    /*
     * Disabled servers will be brought down, but won't be restarted.
     * (see DHCPServer::start)
     */
    HRESULT hrc = stop();
    if (SUCCEEDED(hrc))
        hrc = start(m->networkName, m->trunkName, m->trunkType);
    return hrc;
}


HRESULT DHCPServer::start(const com::Utf8Str &aNetworkName,
                          const com::Utf8Str &aTrunkName,
                          const com::Utf8Str &aTrunkType)
{
    /* Silently ignore attempts to run disabled servers. */
    if (!m->enabled)
        return S_OK;

    /**
     * @todo: the existing code cannot handle concurrent attempts to start DHCP server.
     * Note that technically it may receive different parameters from different callers.
     */
    m->networkName = aNetworkName;
    m->trunkName   = aTrunkName;
    m->trunkType   = aTrunkType;
    HRESULT hrc = i_calcLeaseFilename(aNetworkName);
    if (FAILED(hrc))
        return hrc;

    m->dhcp.clearOptions(); /* (Not DHCP options, but command line options for the service) */

#ifdef VBOX_WITH_DHCPD

    /*
     * Create configuration file path.
     */
    /** @todo put this next to the leases file.   */
    int rc = RTPathTemp(m->tempConfigFileName, sizeof(m->tempConfigFileName));
    if (RT_SUCCESS(rc))
        rc = RTPathAppend(m->tempConfigFileName, sizeof(m->tempConfigFileName), "dhcp-config-XXXXX.xml");
    if (RT_SUCCESS(rc))
        rc = RTFileCreateTemp(m->tempConfigFileName, 0600);
    if (RT_FAILURE(rc))
    {
        m->tempConfigFileName[0] = '\0';
        return E_FAIL;
    }

    /*
     * Produce the DHCP server configuration.
     */
    xml::Document doc;
    xml::ElementNode *pElmRoot = doc.createRootElement("DHCPServer");
    pElmRoot->setAttribute("networkName", m->networkName);
    if (m->trunkName.isNotEmpty())
        pElmRoot->setAttribute("trunkName", m->trunkName);
    pElmRoot->setAttribute("trunkType", m->trunkType);
    pElmRoot->setAttribute("IPAddress",  m->IPAddress);
    pElmRoot->setAttribute("networkMask", m->GlobalDhcpOptions[DhcpOpt_SubnetMask].text);
    pElmRoot->setAttribute("lowerIP", m->lowerIP);
    pElmRoot->setAttribute("upperIP", m->upperIP);
    pElmRoot->setAttribute("leaseFilename", m->strLeaseFilename);

    /* Process global options */
    xml::ElementNode *pOptions = pElmRoot->createChild("Options");
    for (settings::DhcpOptionMap::const_iterator it = m->GlobalDhcpOptions.begin(); it != m->GlobalDhcpOptions.end(); ++it)
        addOptionChild(pOptions, (*it).first, (*it).second);

    /* Process network-adapter-specific options */
    AutoReadLock alock(this COMMA_LOCKVAL_SRC_POS);
    hrc = S_OK;
    ComPtr<IMachine> machine;
    ComPtr<INetworkAdapter> nic;
    settings::VmSlot2OptionsIterator it;
    for (it = m->VmSlot2Options.begin(); it != m->VmSlot2Options.end(); ++it)
    {
        alock.release();
        hrc = mVirtualBox->FindMachine(Bstr(it->first.VmName).raw(), machine.asOutParam());
        alock.acquire();

        if (FAILED(hrc))
            continue;

        alock.release();
        hrc = machine->GetNetworkAdapter(it->first.Slot, nic.asOutParam());
        alock.acquire();

        if (FAILED(hrc))
            continue;

        com::Bstr mac;

        alock.release();
        hrc = nic->COMGETTER(MACAddress)(mac.asOutParam());
        alock.acquire();

        if (FAILED(hrc)) /* no MAC address ??? */
            continue;

        /* Convert MAC address from XXXXXXXXXXXX to XX:XX:XX:XX:XX:XX */
        Utf8Str strMacWithoutColons(mac);
        const char *pszSrc = strMacWithoutColons.c_str();
        RTMAC binaryMac;
        if (RTStrConvertHexBytes(pszSrc, &binaryMac, sizeof(binaryMac), 0) != VINF_SUCCESS)
            continue;
        char szMac[18]; /* "XX:XX:XX:XX:XX:XX" */
        if (RTStrPrintHexBytes(szMac, sizeof(szMac), &binaryMac, sizeof(binaryMac), RTSTRPRINTHEXBYTES_F_SEP_COLON) != VINF_SUCCESS)
            continue;

        xml::ElementNode *pMacConfig = pElmRoot->createChild("Config");
        pMacConfig->setAttribute("MACAddress", szMac);

        com::Utf8Str encodedOption;
        settings::DhcpOptionMap &map = i_findOptMapByVmNameSlot(it->first.VmName, it->first.Slot);
        settings::DhcpOptionMap::const_iterator itAdapterOption;
        for (itAdapterOption = map.begin(); itAdapterOption != map.end(); ++itAdapterOption)
            addOptionChild(pMacConfig, (*itAdapterOption).first, (*itAdapterOption).second);
    }

    xml::XmlFileWriter writer(doc);
    writer.write(m->tempConfigFileName, false);

    m->dhcp.setOption(DHCPServerRunner::kDsrKeyConfig, m->tempConfigFileName);    /* command line options, not dhcp ones. */
    m->dhcp.setOption(DHCPServerRunner::kDsrKeyComment, m->networkName.c_str());

#else /* !VBOX_WITH_DHCPD */
    /* Main is needed for NATNetwork */
    if (m->router)
        m->dhcp.setOption(NetworkServiceRunner::kNsrKeyNeedMain, "on");

    /* Commmon Network Settings */
    m->dhcp.setOption(NetworkServiceRunner::kNsrKeyNetwork, aNetworkName.c_str());

    if (!aTrunkName.isEmpty())
        m->dhcp.setOption(NetworkServiceRunner::kNsrTrunkName, aTrunkName.c_str());

    m->dhcp.setOption(NetworkServiceRunner::kNsrKeyTrunkType, aTrunkType.c_str());

    /* XXX: should this MAC default initialization moved to NetworkServiceRunner? */
    char strMAC[32];
    Guid guid;
    guid.create();
    RTStrPrintf (strMAC, sizeof(strMAC), "08:00:27:%02X:%02X:%02X",
                 guid.raw()->au8[0],
                 guid.raw()->au8[1],
                 guid.raw()->au8[2]);
    m->dhcp.setOption(NetworkServiceRunner::kNsrMacAddress, strMAC);
    m->dhcp.setOption(NetworkServiceRunner::kNsrIpAddress,  Utf8Str(m->IPAddress).c_str());
    m->dhcp.setOption(NetworkServiceRunner::kNsrIpNetmask, Utf8Str(m->GlobalDhcpOptions[DhcpOpt_SubnetMask].text).c_str());
    m->dhcp.setOption(DHCPServerRunner::kDsrKeyLowerIp, Utf8Str(m->lowerIP).c_str());
    m->dhcp.setOption(DHCPServerRunner::kDsrKeyUpperIp, Utf8Str(m->upperIP).c_str());
#endif /* !VBOX_WITH_DHCPD */

    /* XXX: This parameters Dhcp Server will fetch via API */
    return RT_FAILURE(m->dhcp.start(!m->router /* KillProcOnExit */)) ? E_FAIL : S_OK;
    //m->dhcp.detachFromServer(); /* need to do this to avoid server shutdown on runner destruction */
}


HRESULT DHCPServer::stop (void)
{
#ifdef VBOX_WITH_DHCPD
    if (m->tempConfigFileName[0])
    {
        RTFileDelete(m->tempConfigFileName);
        m->tempConfigFileName[0] = 0;
    }
#endif /* VBOX_WITH_DHCPD */
    return RT_FAILURE(m->dhcp.stop()) ? E_FAIL : S_OK;
}


HRESULT DHCPServer::findLeaseByMAC(const com::Utf8Str &aMac, LONG aType,
                                    com::Utf8Str &aAddress, com::Utf8Str &aState, LONG64 *aIssued, LONG64 *aExpire)
{
    /* Reset output before we start */
    *aIssued = 0;
    *aExpire = 0;
    aAddress.setNull();
    aState.setNull();

    /*
     * Convert and check input.
     */
    RTMAC MacAddress;
    int vrc = RTStrConvertHexBytes(aMac.c_str(), &MacAddress, sizeof(MacAddress), RTSTRCONVERTHEXBYTES_F_SEP_COLON);
    if (vrc != VINF_SUCCESS)
        return setErrorBoth(E_INVALIDARG, vrc, tr("Invalid MAC address '%s': %Rrc"), aMac.c_str(), vrc);
    if (aType != 0)
        return setError(E_INVALIDARG, tr("flags must be zero (not %#x)"), aType);

    /*
     * Make sure we've got a lease filename to work with.
     */
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
    if (m->strLeaseFilename.isEmpty())
    {
        HRESULT hrc = i_calcLeaseFilename(m->networkName.isEmpty() ? mName : m->networkName);
        if (FAILED(hrc))
            return hrc;
    }

    /*
     * Try at least twice to read the lease database, more if busy.
     */
    uint64_t const nsStart = RTTimeNanoTS();
    for (uint32_t uReadAttempt = 0; ; uReadAttempt++)
    {
        /*
         * Try read the file.
         */
        xml::Document doc;
        try
        {
            xml::XmlFileParser parser;
            parser.read(m->strLeaseFilename.c_str(), doc);
        }
        catch (const xml::EIPRTFailure &e)
        {
            vrc = e.rc();
            LogThisFunc(("caught xml::EIPRTFailure: rc=%Rrc (attempt %u, msg=%s)\n", vrc, uReadAttempt, e.what()));
            if (   (   vrc == VERR_FILE_NOT_FOUND
                    || vrc == VERR_OPEN_FAILED
                    || vrc == VERR_ACCESS_DENIED
                    || vrc == VERR_SHARING_VIOLATION
                    || vrc == VERR_READ_ERROR /*?*/)
                && (   uReadAttempt == 0
                    || (   uReadAttempt < 64
                        && RTTimeNanoTS() - nsStart < RT_NS_1SEC / 4)) )
            {
                alock.release();

                if (uReadAttempt > 0)
                    RTThreadYield();
                RTThreadSleep(8/*ms*/);

                alock.acquire();
                LogThisFunc(("Retrying...\n"));
                continue;
            }
            return setErrorBoth(VBOX_E_FILE_ERROR, vrc, "Reading '%s' failed: %Rrc - %s",
                                m->strLeaseFilename.c_str(), vrc, e.what());
        }
        catch (const RTCError &e)
        {
            if (e.what())
                return setError(VBOX_E_FILE_ERROR, "Reading '%s' failed: %s", m->strLeaseFilename.c_str(), e.what());
            return setError(VBOX_E_FILE_ERROR, "Reading '%s' failed: RTCError", m->strLeaseFilename.c_str());
        }
        catch (std::bad_alloc &)
        {
            return E_OUTOFMEMORY;
        }
        catch (...)
        {
            AssertFailed();
            return setError(VBOX_E_FILE_ERROR, tr("Reading '%s' failed: Unexpected exception"), m->strLeaseFilename.c_str());
        }

        /*
         * Look for that mac address.
         */
        xml::ElementNode *pElmRoot = doc.getRootElement();
        if (pElmRoot && pElmRoot->nameEquals("Leases"))
        {
            xml::NodesLoop          it(*pElmRoot);
            const xml::ElementNode *pElmLease;
            while ((pElmLease = it.forAllNodes()) != NULL)
                if (pElmLease->nameEquals("Lease"))
                {
                    const char *pszCurMacAddress = pElmLease->findAttributeValue("mac");
                    RTMAC       CurMacAddress;
                    if (   pszCurMacAddress
                        && RT_SUCCESS(RTNetStrToMacAddr(pszCurMacAddress, &CurMacAddress))
                        && memcmp(&CurMacAddress, &MacAddress, sizeof(MacAddress)) == 0)
                    {
                        /*
                         * Found it!
                         */
                        xml::ElementNode const *pElmTime    = pElmLease->findChildElement("Time");
                        int64_t                 secIssued   = 0;
                        uint32_t                cSecsToLive = 0;
                        if (pElmTime)
                        {
                            pElmTime->getAttributeValue("issued", &secIssued);
                            pElmTime->getAttributeValue("expiration", &cSecsToLive);
                            *aIssued = secIssued;
                            *aExpire = secIssued + cSecsToLive;
                        }
                        try
                        {
                            aAddress = pElmLease->findChildElementAttributeValue("Address", "value");
                            aState   = pElmLease->findAttributeValue("state");
                        }
                        catch (std::bad_alloc &)
                        {
                            return E_OUTOFMEMORY;
                        }

                        /* Check if the lease has expired in the mean time. */
                        HRESULT hrc = S_OK;
                        RTTIMESPEC Now;
                        if (   (aState.equals("acked") || aState.equals("offered") || aState.isEmpty())
                            && secIssued + cSecsToLive < RTTimeSpecGetSeconds(RTTimeNow(&Now)))
                            hrc = aState.assignNoThrow("expired");
                        return hrc;
                    }
                }
        }
        break;
    }

    return setError(VBOX_E_OBJECT_NOT_FOUND, tr("Could not find a lease for %RTmac"), &MacAddress);
}


/**
 * Calculates and updates the value of strLeaseFilename given @a aNetwork.
 */
HRESULT DHCPServer::i_calcLeaseFilename(const com::Utf8Str &aNetwork)
{
    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);

    /* The lease file must be the same as we used the last time, so careful when changing this code. */
    int vrc = m->strLeaseFilename.assignNoThrow(mVirtualBox->i_homeDir());
    if (RT_SUCCESS(vrc))
        vrc = RTPathAppendCxx(m->strLeaseFilename, aNetwork);
    if (RT_SUCCESS(vrc))
        vrc = m->strLeaseFilename.appendNoThrow("-Dhcpd.leases");
    if (RT_SUCCESS(vrc))
    {
        RTPathPurgeFilename(RTPathFilename(m->strLeaseFilename.mutableRaw()), RTPATH_STR_F_STYLE_HOST);
        m->strLeaseFilename.jolt();
        return S_OK;
    }
    return setErrorBoth(E_FAIL, vrc, tr("Failed to construct lease filename: %Rrc"), vrc);
}

settings::DhcpOptionMap &DHCPServer::i_findOptMapByVmNameSlot(const com::Utf8Str &aVmName,
                                                              LONG aSlot)
{
    return m->VmSlot2Options[settings::VmNameSlotKey(aVmName, aSlot)];
}