Cppcheck report - cppcheck report: src/lib/dhcpsrv/testutils/alloc_engine_utils.cc

// Copyright (C) 2012-2024 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include <config.h>

#include <dhcp/duid.h>
#include <dhcp/dhcp4.h>
#include <dhcp/dhcp6.h>
#include <dhcp/pkt4.h>
#include <dhcp/pkt6.h>
#include <dhcpsrv/host_mgr.h>
#include <dhcpsrv/lease_mgr.h>
#include <dhcpsrv/memfile_lease_mgr.h>
#include <hooks/hooks_manager.h>
#include <hooks/callout_handle.h>
#include <stats/stats_mgr.h>
#include <testutils/gtest_utils.h>

#include <dhcpsrv/testutils/test_utils.h>
#include <dhcpsrv/testutils/alloc_engine_utils.h>

#include <boost/shared_ptr.hpp><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <boost/scoped_ptr.hpp><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.

#include <iostream><--- 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.
#include <algorithm><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <set><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <time.h><--- Include file:  not found. Please note: Cppcheck does not need standard library headers to get proper results.

using namespace std;
using namespace isc::hooks;
using namespace isc::asiolink;
using namespace isc::stats;
using namespace isc::util;

namespace isc {
namespace dhcp {
namespace test {

bool testStatistics(const std::string& stat_name, const int64_t exp_value,
                    const SubnetID subnet_id, bool fail_missing) {
    try {
        std::string name = (subnet_id == SUBNET_ID_UNUSED ? stat_name :
                            StatsMgr::generateName("subnet", subnet_id, stat_name));
        ObservationPtr observation = StatsMgr::instance().getObservation(name);
        if (observation) {
            if (observation->getInteger().first != exp_value) {
                ADD_FAILURE()
                    << "value of the observed statistics '"
                    << name << "' ("
                    << observation->getInteger().first << ") "
                    << "doesn't match expected value (" << exp_value << ")";
            }
            return (observation->getInteger().first == exp_value);
        } else {
            if (fail_missing) {
                ADD_FAILURE() << "Expected statistic " << name
                              << " not found.";
            } else {
                if (exp_value) {
                    ADD_FAILURE() << "Checking non existent statistic and expected value is not 0. Broken test?";
                }
            }
        }
        if (subnet_id != SUBNET_ID_UNUSED) {
            name = StatsMgr::generateName("subnet", subnet_id, StatsMgr::generateName("pool", 0, stat_name));
            observation = StatsMgr::instance().getObservation(name);
            if (observation) {
                if (observation->getInteger().first != exp_value) {
                    ADD_FAILURE()
                        << "value of the observed statistics '"
                        << name << "' ("
                        << observation->getInteger().first << ") "
                        << "doesn't match expected value (" << exp_value << ")";
                }
                return (observation->getInteger().first == exp_value);
            } else {
                if (fail_missing) {
                    ADD_FAILURE() << "Expected statistic " << name
                                  << " not found.";
                } else {
                    if (exp_value) {
                        ADD_FAILURE() << "Checking non existent statistic and expected value is not 0. Broken test?";
                    }
                }
            }
        }
    } catch (const std::exception& e) {
        ADD_FAILURE() << "Uncaught exception " << e.what();
    } catch (...) {
        ADD_FAILURE() << "Unknown exception";
    }
    return (false);
}

int64_t getStatistics(const std::string& stat_name, const SubnetID subnet_id) {
    try {
        std::string name = (subnet_id == SUBNET_ID_UNUSED ? stat_name :
                            StatsMgr::generateName("subnet", subnet_id, stat_name));
        ObservationPtr observation = StatsMgr::instance().getObservation(name);
        if (observation) {
            return (observation->getInteger().first);
        }
    } catch (const std::exception& e) {
        ADD_FAILURE() << "Uncaught exception " << e.what();
    } catch (...) {
        ADD_FAILURE() << "Unknown exception";
    }
    return (0);
}

void
AllocEngine4Test::testReuseLease4(const AllocEnginePtr& engine,
                                  Lease4Ptr& existing_lease,<--- Parameter 'existing_lease' can be declared as reference to const
                                  const std::string& addr,
                                  const bool fake_allocation,
                                  ExpectedResult exp_result,
                                  Lease4Ptr& result) {
    ASSERT_TRUE(engine);

    if (existing_lease) {
        // If an existing lease was specified, we need to add it to the
        // database. Let's wipe any leases for that address (if any). We
        // ignore any errors (previous lease may not exist)
        (void) LeaseMgrFactory::instance().deleteLease(existing_lease);

        // Let's add it.
        ASSERT_TRUE(LeaseMgrFactory::instance().addLease(existing_lease));
    }

    // A client comes along, asking specifically for a given address
    AllocEngine::ClientContext4 ctx(subnet_, clientid_, hwaddr_,
                                    IOAddress(addr), false, false,
                                    "", fake_allocation);
    if (fake_allocation) {
        ctx.query_.reset(new Pkt4(DHCPDISCOVER, 1234));
    } else {
        ctx.query_.reset(new Pkt4(DHCPREQUEST, 1234));
    }
    result = engine->allocateLease4(ctx);

    switch (exp_result) {
    case SHOULD_PASS:
        ASSERT_TRUE(result);

        checkLease4(result);
        break;

    case SHOULD_FAIL:
        ASSERT_FALSE(result);
        break;
    }
}

Lease4Ptr
AllocEngine4Test::generateDeclinedLease(const std::string& addr,
                                        time_t probation_period,
                                        int32_t expired) {
    // There's an assumption that hardware address is always present for IPv4
    // packet (always non-null). Client-id is optional (may be null).
    HWAddrPtr hwaddr(new HWAddr());
    time_t now = time(NULL);
    Lease4Ptr declined(new Lease4(addr, hwaddr, ClientIdPtr(), 495,
                                  now, subnet_->getID()));
    declined->decline(probation_period);
    declined->cltt_ = now - probation_period + expired;
    return (declined);
}

AllocEngine6Test::AllocEngine6Test() {
    CfgMgr::instance().clear();

    // This lease mgr needs to exist to before configuration commits.
    factory_.create("type=memfile universe=6 persist=false");

    duid_ = DuidPtr(new DUID(std::vector<uint8_t>(8, 0x42)));
    iaid_ = 42;

    // Create fresh instance of the HostMgr, and drop any previous HostMgr state.
    HostMgr::instance().create();

    // Let's use odd hardware type to check if there is no Ethernet
    // hardcoded anywhere.
    const uint8_t mac[] = { 0, 1, 22, 33, 44, 55 };
    hwaddr_ = HWAddrPtr(new HWAddr(mac, sizeof(mac), HTYPE_FDDI));
    // Initialize a subnet and short address pool.
    initSubnet(IOAddress("2001:db8:1::"),
               IOAddress("2001:db8:1::10"),
               IOAddress("2001:db8:1::20"),
               IOAddress("2001:db8:1:2::"),
               64, 80);

    initFqdn("", false, false);

    StatsMgr::instance().resetAll();
}

void
AllocEngine6Test::initSubnet(const asiolink::IOAddress& subnet,
                             const asiolink::IOAddress& pool_start,
                             const asiolink::IOAddress& pool_end,
                             const asiolink::IOAddress& pd_pool_prefix,
                             const uint8_t pd_pool_length,
                             const uint8_t pd_delegated_length) {
    CfgMgr& cfg_mgr = CfgMgr::instance();

    static SubnetID id(1);
    subnet_ = Subnet6::create(subnet, 56, 100, 200, 300, 400, id++);
    pool_ = Pool6Ptr(new Pool6(Lease::TYPE_NA, pool_start, pool_end));

    subnet_->addPool(pool_);

    if (!pd_pool_prefix.isV6Zero()) {
        pd_pool_ = Pool6Ptr(new Pool6(Lease::TYPE_PD, pd_pool_prefix,
                                      pd_pool_length, pd_delegated_length));
    }
    subnet_->addPool(pd_pool_);

    cfg_mgr.getStagingCfg()->getCfgSubnets6()->add(subnet_);
    cfg_mgr.commit();
}

void
AllocEngine6Test::findReservation(AllocEngine& engine,
    AllocEngine::ClientContext6& ctx) {
    engine.findReservation(ctx);
    // Let's check whether there's a hostname specified in the reservation
    if (ctx.currentHost()) {
        std::string hostname = ctx.currentHost()->getHostname();
        // If there is, let's use it
        if (!hostname.empty()) {
            ctx.hostname_ = hostname;
        }
    }
}

HostPtr
AllocEngine6Test::createHost6HWAddr(bool add_to_host_mgr, IPv6Resrv::Type type,
                                    HWAddrPtr& hwaddr, const asiolink::IOAddress& addr,
                                    uint8_t prefix_len) {
    HostPtr host(new Host(&hwaddr->hwaddr_[0], hwaddr->hwaddr_.size(),
                          Host::IDENT_HWADDR, SUBNET_ID_UNUSED, subnet_->getID(),
                          asiolink::IOAddress("0.0.0.0")));
    IPv6Resrv resv(type, addr, prefix_len);
    host->addReservation(resv);

    if (add_to_host_mgr) {
        CfgMgr::instance().getStagingCfg()->getCfgHosts()->add(host);
        CfgMgr::instance().commit();
    }
    return (host);
}

Lease6Collection
AllocEngine6Test::allocateTest(AllocEngine& engine, const Pool6Ptr& pool,
                               const asiolink::IOAddress& hint, bool fake,
                               bool in_pool, uint8_t hint_prefix_length) {
    Lease::Type type = pool->getType();
    uint8_t expected_len = pool->getLength();

    Pkt6Ptr query(new Pkt6(fake ? DHCPV6_SOLICIT : DHCPV6_REQUEST, 1234));

    AllocEngine::ClientContext6 ctx(subnet_, duid_, false, false, "",
                                    fake, query);
    ctx.currentIA().iaid_ = iaid_;
    ctx.currentIA().type_ = type;
    ctx.currentIA().addHint(hint, hint_prefix_length);

    Lease6Collection leases;

    findReservation(engine, ctx);
    EXPECT_NO_THROW(leases = engine.allocateLeases6(ctx));

    for (auto const& it : leases) {

        // Do all checks on the lease
        checkLease6(duid_, it, type, expected_len, in_pool, in_pool);

        // Check that context has been updated with allocated addresses or
        // prefixes.
        checkAllocatedResources(it, ctx);

        // Check that the lease is indeed in LeaseMgr
        Lease6Ptr from_mgr = LeaseMgrFactory::instance().getLease6(type,
                                                                   it->addr_);
        if (!fake) {
            // This is a real (REQUEST) allocation, the lease must be in the DB
            EXPECT_TRUE(from_mgr) << "Lease " << from_mgr->addr_.toText()
                                  << " returned by allocateLeases6(), "
                                  << "but was not present in LeaseMgr";
            if (!from_mgr) {
                return (leases);
            }

            // Now check that the lease in LeaseMgr has the same parameters
            detailCompareLease(it, from_mgr);
        } else {
            // This is a fake (SOLICIT) allocation, the lease must not be in DB
            EXPECT_FALSE(from_mgr) << "Lease " << from_mgr->addr_.toText()
                                   << " returned by allocateLeases6(), "
                                   << "was present in LeaseMgr (expected to be"
                                   << " not present)";
            if (from_mgr) {
                return (leases);
            }
        }
    }

    return (leases);
}

Lease6Ptr
AllocEngine6Test::simpleAlloc6Test(const Pool6Ptr& pool, const IOAddress& hint,
                                   bool fake, bool in_pool) {
    return (simpleAlloc6Test(pool, duid_, hint, fake, in_pool));
}

Lease6Ptr
AllocEngine6Test::simpleAlloc6Test(const Pool6Ptr& pool, const IOAddress& hint,
                                   uint32_t preferred, uint32_t valid,
                                   uint32_t exp_preferred, uint32_t exp_valid,
                                   ClientClassDefPtr class_def) {
    Lease::Type type = pool->getType();
    uint8_t expected_len = pool->getLength();

    boost::scoped_ptr<AllocEngine> engine;
    EXPECT_NO_THROW(engine.reset(new AllocEngine(100)));
    // We can't use ASSERT macros in non-void methods
    EXPECT_TRUE(engine);
    if (!engine) {
        return (Lease6Ptr());
    }

    Pkt6Ptr query(new Pkt6(DHCPV6_REQUEST, 1234));

    AllocEngine::ClientContext6 ctx(subnet_, duid_, false, false, "", false, query);
    ctx.hwaddr_ = hwaddr_;
    ctx.addHostIdentifier(Host::IDENT_HWADDR, hwaddr_->hwaddr_);
    ctx.currentIA().iaid_ = iaid_;
    ctx.currentIA().type_ = type;
    ctx.currentIA().addHint(hint, expected_len, preferred, valid);
    subnet_->setPreferred(Triplet<uint32_t>(200, 300, 400));
    subnet_->setValid(Triplet<uint32_t>(300, 400, 500));

    if (class_def) {
        std::cout << "adding class defintion" << std::endl;
        CfgMgr::instance().getStagingCfg()->getClientClassDictionary()->addClass(class_def);
        ctx.query_->addClass(class_def->getName());
    }

    // Set some non-standard callout status to make sure it doesn't affect the
    // allocation.
    ctx.callout_handle_ = HooksManager::createCalloutHandle();
    ctx.callout_handle_->setStatus(CalloutHandle::NEXT_STEP_SKIP);

    findReservation(*engine, ctx);
    Lease6Ptr lease;
    EXPECT_NO_THROW(lease = expectOneLease(engine->allocateLeases6(ctx)));

    // Check that we got a lease
    EXPECT_TRUE(lease);
    if (!lease) {
        return (Lease6Ptr());
    }

    // Do all checks on the lease
    checkLease6(duid_, lease, type, expected_len, true, true);

    // Check expected preferred and valid lifetimes.
    EXPECT_EQ(exp_preferred, lease->preferred_lft_);
    EXPECT_EQ(exp_valid, lease->valid_lft_);

    return (lease);
}

Lease6Ptr
AllocEngine6Test::simpleAlloc6Test(const Pool6Ptr& pool, const DuidPtr& duid,
                                   const IOAddress& hint, bool fake, bool in_pool) {
    Lease::Type type = pool->getType();
    uint8_t expected_len = pool->getLength();

    boost::scoped_ptr<AllocEngine> engine;
    EXPECT_NO_THROW(engine.reset(new AllocEngine(100)));
    // We can't use ASSERT macros in non-void methods
    EXPECT_TRUE(engine);
    if (!engine) {
        return (Lease6Ptr());
    }

    Pkt6Ptr query(new Pkt6(fake ? DHCPV6_SOLICIT : DHCPV6_REQUEST, 1234));

    AllocEngine::ClientContext6 ctx(subnet_, duid, false, false, "", fake, query);
    ctx.hwaddr_ = hwaddr_;
    ctx.addHostIdentifier(Host::IDENT_HWADDR, hwaddr_->hwaddr_);
    ctx.currentIA().iaid_ = iaid_;
    ctx.currentIA().type_ = type;
    ctx.currentIA().addHint(hint);

    // Set some non-standard callout status to make sure it doesn't affect the
    // allocation.
    ctx.callout_handle_ = HooksManager::createCalloutHandle();
    ctx.callout_handle_->setStatus(CalloutHandle::NEXT_STEP_SKIP);

    findReservation(*engine, ctx);
    Lease6Ptr lease;
    EXPECT_NO_THROW(lease = expectOneLease(engine->allocateLeases6(ctx)));

    // Check that we got a lease
    EXPECT_TRUE(lease);
    if (!lease) {
        return (Lease6Ptr());
    }

    // Do all checks on the lease
    checkLease6(duid, lease, type, expected_len, in_pool, in_pool);

    // Check that the lease is indeed in LeaseMgr
    Lease6Ptr from_mgr = LeaseMgrFactory::instance().getLease6(type, lease->addr_);
    if (!fake) {
        // This is a real (REQUEST) allocation, the lease must be in the DB
        EXPECT_TRUE(from_mgr);
        if (!from_mgr) {
            return (Lease6Ptr());
        }

        // Now check that the lease in LeaseMgr has the same parameters
        detailCompareLease(lease, from_mgr);
    } else {
        // This is a fake (SOLICIT) allocation, the lease must not be in DB
        EXPECT_FALSE(from_mgr);
        if (from_mgr) {
            return (Lease6Ptr());
        }
    }

    return (lease);
}

Lease6Collection
AllocEngine6Test::renewTest(AllocEngine& engine, const Pool6Ptr& pool,
                            AllocEngine::HintContainer& hints,<--- Parameter 'hints' can be declared as reference to const
                            bool in_subnet, bool in_pool) {
    Lease::Type type = pool->getType();
    uint8_t expected_len = pool->getLength();

    Pkt6Ptr query(new Pkt6(DHCPV6_RENEW, 1234));
    AllocEngine::ClientContext6 ctx(subnet_, duid_, false, false, "",
                                    false, query);
    ctx.currentIA().hints_ = hints;
    ctx.currentIA().iaid_ = iaid_;
    ctx.currentIA().type_ = type;

    findReservation(engine, ctx);
    Lease6Collection leases = engine.renewLeases6(ctx);

    for (auto const& it : leases) {

        // Do all checks on the lease
        checkLease6(duid_, it, type, expected_len, in_subnet, in_pool);

        // Check that context has been updated with allocated addresses or
        // prefixes.
        checkAllocatedResources(it, ctx);

        // Check that the lease is indeed in LeaseMgr
        Lease6Ptr from_mgr = LeaseMgrFactory::instance().getLease6(type,
                                                                   it->addr_);

        // This is a real (REQUEST) allocation, the lease must be in the DB
        EXPECT_TRUE(from_mgr) << "Lease " << from_mgr->addr_.toText()
                              << " returned by allocateLeases6(), "
                              << "but was not present in LeaseMgr";
        if (!from_mgr) {
            return (leases);
        }

        // Now check that the lease in LeaseMgr has the same parameters
        detailCompareLease(it, from_mgr);
    }

    return (leases);
}

void
AllocEngine6Test::allocWithUsedHintTest(Lease::Type type, IOAddress used_addr,
                                        IOAddress requested,
                                        uint8_t expected_pd_len) {
    boost::scoped_ptr<AllocEngine> engine;
    ASSERT_NO_THROW(engine.reset(new AllocEngine(100)));
    ASSERT_TRUE(engine);

    // Let's create a lease and put it in the LeaseMgr
    DuidPtr duid2 = boost::shared_ptr<DUID>(new DUID(vector<uint8_t>(8, 0xff)));
    time_t now = time(NULL);
    Lease6Ptr used(new Lease6(type, used_addr,
                              duid2, 1, 2, now, subnet_->getID()));
    ASSERT_TRUE(LeaseMgrFactory::instance().addLease(used));

    // Another client comes in and request an address that is in pool, but
    // unfortunately it is used already. The same address must not be allocated
    // twice.

    Pkt6Ptr query(new Pkt6(DHCPV6_REQUEST, 1234));
    AllocEngine::ClientContext6 ctx(subnet_, duid_, false, false, "", false,
                                    query);
    ctx.currentIA().iaid_ = iaid_;
    ctx.currentIA().type_ = type;
    ctx.currentIA().addHint(requested);

    Lease6Ptr lease;
    EXPECT_NO_THROW(lease = expectOneLease(engine->allocateLeases6(ctx)));

    // Check that we got a lease
    ASSERT_TRUE(lease);

    // Allocated address must be different
    EXPECT_NE(used_addr, lease->addr_);

    // We should NOT get what we asked for, because it is used already
    EXPECT_NE(requested, lease->addr_);

    // Do all checks on the lease
    checkLease6(duid_, lease, type, expected_pd_len);

    // Check that the lease is indeed in LeaseMgr
    Lease6Ptr from_mgr = LeaseMgrFactory::instance().getLease6(lease->type_,
                                                               lease->addr_);
    ASSERT_TRUE(from_mgr);

    // Now check that the lease in LeaseMgr has the same parameters
    detailCompareLease(lease, from_mgr);
}

void
AllocEngine6Test::allocBogusHint6(Lease::Type type, asiolink::IOAddress hint,
                                  uint8_t expected_pd_len) {
    boost::scoped_ptr<AllocEngine> engine;
    ASSERT_NO_THROW(engine.reset(new AllocEngine(100)));
    ASSERT_TRUE(engine);

    // Client would like to get a 3000::abc lease, which does not belong to any
    // supported lease. Allocation engine should ignore it and carry on
    // with the normal allocation

    Pkt6Ptr query(new Pkt6(DHCPV6_REQUEST, 1234));
    AllocEngine::ClientContext6 ctx(subnet_, duid_, false, false, "", false,
                                    query);
    ctx.currentIA().iaid_ = iaid_;
    ctx.currentIA().type_ = type;
    ctx.currentIA().addHint(hint);

    Lease6Ptr lease;
    EXPECT_NO_THROW(lease = expectOneLease(engine->allocateLeases6(ctx)));

    // Check that we got a lease
    ASSERT_TRUE(lease);

    // We should NOT get what we asked for, because it is used already
    EXPECT_NE(hint, lease->addr_);

    // Do all checks on the lease
    checkLease6(duid_, lease, type, expected_pd_len);

    // Check that the lease is indeed in LeaseMgr
    Lease6Ptr from_mgr = LeaseMgrFactory::instance().getLease6(lease->type_,
                                                               lease->addr_);
    ASSERT_TRUE(from_mgr);

    // Now check that the lease in LeaseMgr has the same parameters
    detailCompareLease(lease, from_mgr);
}

void
AllocEngine6Test::testReuseLease6(const AllocEnginePtr& engine,
                                  Lease6Ptr& existing_lease,<--- Parameter 'existing_lease' can be declared as reference to const
                                  const std::string& addr,
                                  const bool fake_allocation,
                                  ExpectedResult exp_result,
                                  Lease6Ptr& result) {
    ASSERT_TRUE(engine);

    if (existing_lease) {
        // If an existing lease was specified, we need to add it to the
        // database. Let's wipe any leases for that address (if any). We
        // ignore any errors (previous lease may not exist)
        (void) LeaseMgrFactory::instance().deleteLease(existing_lease);

        // Let's add it.
        ASSERT_TRUE(LeaseMgrFactory::instance().addLease(existing_lease));
    }

    // A client comes along, asking specifically for a given address

    Pkt6Ptr query(new Pkt6(fake_allocation ? DHCPV6_SOLICIT : DHCPV6_REQUEST, 1234));
    AllocEngine::ClientContext6 ctx(subnet_, duid_, false, false, "",
                                    fake_allocation, query);
    ctx.currentIA().iaid_ = iaid_;
    ctx.currentIA().addHint(IOAddress(addr));

    Lease6Collection leases;

    leases = engine->allocateLeases6(ctx);

    switch (exp_result) {
    case SHOULD_PASS:
        ASSERT_FALSE(leases.empty());
        ASSERT_EQ(1, leases.size());
        result = leases[0];

        checkLease6(duid_, result, Lease::TYPE_NA, 128);
        break;

    case SHOULD_FAIL:
        ASSERT_TRUE(leases.empty());
        break;
    }
}

Lease6Ptr
AllocEngine6Test::generateDeclinedLease(const std::string& addr,
                                        time_t probation_period,
                                        int32_t expired) {
    Lease6Ptr declined(new Lease6(Lease::TYPE_NA, IOAddress(addr),
                       duid_, iaid_, 100, 100, subnet_->getID()));

    time_t now = time(NULL);
    declined->decline(probation_period);
    declined->cltt_ = now - probation_period + expired;
    return (declined);
}

void
AllocEngine4Test::initSubnet(const asiolink::IOAddress& pool_start,
                             const asiolink::IOAddress& pool_end) {
    CfgMgr& cfg_mgr = CfgMgr::instance();

    static SubnetID id(1);
    subnet_ = Subnet4::create(IOAddress("192.0.2.0"), 24, 1, 2, 3, id++);
    pool_ = Pool4Ptr(new Pool4(pool_start, pool_end));
    subnet_->addPool(pool_);

    EXPECT_NO_THROW_LOG(cfg_mgr.getStagingCfg()->getCfgSubnets4()->add(subnet_));
}

AllocEngine4Test::AllocEngine4Test() {
    CfgMgr::instance().clear();

    // This lease mgr needs to exist to before configuration commits.
    factory_.create("type=memfile universe=4 persist=false");

    // Create fresh instance of the HostMgr, and drop any previous HostMgr state.
    HostMgr::instance().create();

    clientid_ = ClientIdPtr(new ClientId(vector<uint8_t>(8, 0x44)));
    clientid2_ = ClientIdPtr(new ClientId(vector<uint8_t>(8, 0x56)));

    uint8_t mac[] = { 0, 1, 22, 33, 44, 55};

    // Let's use odd hardware type to check if there is no Ethernet
    // hardcoded anywhere.
    hwaddr_ = HWAddrPtr(new HWAddr(mac, sizeof(mac), HTYPE_FDDI));

    // Allocate different MAC address for the tests that require two
    // different MAC addresses.
    ++mac[sizeof(mac) - 1];
    hwaddr2_ = HWAddrPtr(new HWAddr(mac, sizeof (mac), HTYPE_FDDI));

    // instantiate cfg_mgr
    CfgMgr& cfg_mgr = CfgMgr::instance();

    initSubnet(IOAddress("192.0.2.100"), IOAddress("192.0.2.109"));
    cfg_mgr.commit();


    // Create a default context. Note that remaining parameters must be
    // assigned when needed.
    ctx_.subnet_ = subnet_;
    ctx_.clientid_ = clientid_;
    ctx_.hwaddr_ = hwaddr_;
    ctx_.callout_handle_ = HooksManager::createCalloutHandle();
    ctx_.query_.reset(new Pkt4(DHCPREQUEST, 1234));

    StatsMgr::instance().resetAll();
}

}  // namespace test
}  // namespace dhcp
}  // namespace isc