kea/src/bin/dhcp4/tests/hooks_unittest.cc

// Copyright (C) 2015-2016 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 <dhcp4/tests/dhcp4_test_utils.h>
#include <dhcp4/tests/dhcp4_client.h>
#include <dhcp4/json_config_parser.h>
#include <cc/command_interpreter.h>
#include <config/command_mgr.h>
#include <hooks/server_hooks.h>
#include <hooks/hooks_manager.h>
#include <dhcpsrv/cfgmgr.h>
#include <dhcp/tests/iface_mgr_test_config.h>
#include <dhcp/option.h>
#include <asiolink/io_address.h>
#include <dhcp4/tests/marker_file.h>
#include <dhcp4/tests/test_libraries.h>

#include <vector>

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

// Checks if hooks are registered properly.
TEST_F(Dhcpv4SrvTest, Hooks) {
    NakedDhcpv4Srv srv(0);

    // check if appropriate hooks are registered
    int hook_index_buffer4_receive = -1;
    int hook_index_pkt4_receive    = -1;
    int hook_index_select_subnet   = -1;
    int hook_index_lease4_release  = -1;
    int hook_index_pkt4_send       = -1;
    int hook_index_buffer4_send    = -1;

    // check if appropriate indexes are set
    EXPECT_NO_THROW(hook_index_buffer4_receive = ServerHooks::getServerHooks()
                    .getIndex("buffer4_receive"));
    EXPECT_NO_THROW(hook_index_pkt4_receive = ServerHooks::getServerHooks()
                    .getIndex("pkt4_receive"));
    EXPECT_NO_THROW(hook_index_select_subnet = ServerHooks::getServerHooks()
                    .getIndex("subnet4_select"));
    EXPECT_NO_THROW(hook_index_lease4_release = ServerHooks::getServerHooks()
                    .getIndex("lease4_release"));
    EXPECT_NO_THROW(hook_index_pkt4_send = ServerHooks::getServerHooks()
                    .getIndex("pkt4_send"));
    EXPECT_NO_THROW(hook_index_buffer4_send = ServerHooks::getServerHooks()
                    .getIndex("buffer4_send"));

    EXPECT_TRUE(hook_index_buffer4_receive > 0);
    EXPECT_TRUE(hook_index_pkt4_receive > 0);
    EXPECT_TRUE(hook_index_select_subnet > 0);
    EXPECT_TRUE(hook_index_lease4_release > 0);
    EXPECT_TRUE(hook_index_pkt4_send > 0);
    EXPECT_TRUE(hook_index_buffer4_send > 0);
}

// A dummy MAC address, padded with 0s
const uint8_t dummyChaddr[16] = {0, 1, 2, 3, 4, 5, 0, 0,
                                 0, 0, 0, 0, 0, 0, 0, 0 };

// Let's use some creative test content here (128 chars + \0)
const uint8_t dummyFile[] = "Lorem ipsum dolor sit amet, consectetur "
    "adipiscing elit. Proin mollis placerat metus, at "
    "lacinia orci ornare vitae. Mauris amet.";

// Yet another type of test content (64 chars + \0)
const uint8_t dummySname[] = "Lorem ipsum dolor sit amet, consectetur "
    "adipiscing elit posuere.";

/// @brief a class dedicated to Hooks testing in DHCPv4 server
///
/// This class has a number of static members, because each non-static
/// method has implicit 'this' parameter, so it does not match callout
/// signature and couldn't be registered. Furthermore, static methods
/// can't modify non-static members (for obvious reasons), so many
/// fields are declared static. It is still better to keep them as
/// one class rather than unrelated collection of global objects.
class HooksDhcpv4SrvTest : public Dhcpv4SrvTest {

public:

    /// @brief creates Dhcpv4Srv and prepares buffers for callouts
    HooksDhcpv4SrvTest() {

        // Allocate new DHCPv6 Server
        srv_ = new NakedDhcpv4Srv(0);

        // clear static buffers
        resetCalloutBuffers();
    }

    /// @brief destructor (deletes Dhcpv4Srv)
    virtual ~HooksDhcpv4SrvTest() {

        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("buffer4_receive");
        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("buffer4_send");
        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("pkt4_receive");
        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("pkt4_send");
        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("subnet4_select");
        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("lease4_renew");
        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("lease4_release");
        HooksManager::preCalloutsLibraryHandle().deregisterAllCallouts("lease4_decline");

        delete srv_;
    }

    /// @brief creates an option with specified option code
    ///
    /// This method is static, because it is used from callouts
    /// that do not have a pointer to HooksDhcpv4SSrvTest object
    ///
    /// @param option_code code of option to be created
    ///
    /// @return pointer to create option object
    static OptionPtr createOption(uint16_t option_code) {

        char payload[] = {
            0xa, 0xb, 0xc, 0xe, 0xf, 0x10, 0x11, 0x12, 0x13, 0x14
        };

        OptionBuffer tmp(payload, payload + sizeof(payload));
        return OptionPtr(new Option(Option::V4, option_code, tmp));
    }

    /// @brief Generates test packet.
    ///
    /// Allocates and generates on-wire buffer that represents test packet, with all
    /// fixed fields set to non-zero values.  Content is not always reasonable.
    ///
    /// See generateTestPacket1() function that returns exactly the same packet as
    /// Pkt4 object.
    ///
    /// @return pointer to allocated Pkt4 object
    // Returns a vector containing a DHCPv4 packet header.
    Pkt4Ptr
    generateSimpleDiscover() {

        // That is only part of the header. It contains all "short" fields,
        // larger fields are constructed separately.
        uint8_t hdr[] = {
            1, 6, 6, 13,            // op, htype, hlen, hops,
            0x12, 0x34, 0x56, 0x78, // transaction-id
            0, 42, 0x80, 0x00,      // 42 secs, BROADCAST flags
            192, 0, 2, 1,           // ciaddr
            1, 2, 3, 4,             // yiaddr
            192, 0, 2, 255,         // siaddr
            192, 0, 2, 50,          // giaddr
        };

        // Initialize the vector with the header fields defined above.
        vector<uint8_t> buf(hdr, hdr + sizeof(hdr));

        // Append the large header fields.
        copy(dummyChaddr, dummyChaddr + Pkt4::MAX_CHADDR_LEN, back_inserter(buf));
        copy(dummySname, dummySname + Pkt4::MAX_SNAME_LEN, back_inserter(buf));
        copy(dummyFile, dummyFile + Pkt4::MAX_FILE_LEN, back_inserter(buf));

        // Should now have all the header, so check.  The "static_cast" is used
        // to get round an odd bug whereby the linker appears not to find the
        // definition of DHCPV4_PKT_HDR_LEN if it appears within an EXPECT_EQ().
        EXPECT_EQ(static_cast<size_t>(Pkt4::DHCPV4_PKT_HDR_LEN), buf.size());

        // Add magic cookie
        buf.push_back(0x63);
        buf.push_back(0x82);
        buf.push_back(0x53);
        buf.push_back(0x63);

        // Add message type DISCOVER
        buf.push_back(static_cast<uint8_t>(DHO_DHCP_MESSAGE_TYPE));
        buf.push_back(1); // length (just one byte)
        buf.push_back(static_cast<uint8_t>(DHCPDISCOVER));

        Pkt4Ptr dis(new Pkt4(&buf[0], buf.size()));
        // Interface must be selected for a Discover. Server will use the interface
        // name to select a subnet for a client. This test is using fake interfaces
        // and the fake eth0 interface has IPv4 address matching the subnet
        // currently configured for this test.
        dis->setIface("eth1");
        return (dis);
    }

    /// Test callback that stores received callout name and pkt4 value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    buffer4_receive_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("buffer4_receive");

        callout_handle.getArgument("query4", callback_pkt4_);

        callback_argument_names_ = callout_handle.getArgumentNames();
        return (0);
    }

    /// Test callback that changes hwaddr value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    buffer4_receive_change_hwaddr(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("query4", pkt);

        // If there is at least one option with data
        if (pkt->data_.size() >= Pkt4::DHCPV4_PKT_HDR_LEN) {
            // Offset of the first byte of the CHWADDR field. Let's the first
            // byte to some new value that we could later check
            pkt->data_[28] = 0xff;
        }

        // Carry on as usual
        return buffer4_receive_callout(callout_handle);
    }

    /// Test callback that sets skip flag
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    buffer4_receive_skip(CalloutHandle& callout_handle) {

        callout_handle.setStatus(CalloutHandle::NEXT_STEP_SKIP);

        // Carry on as usual
        return buffer4_receive_callout(callout_handle);
    }

    /// test callback that stores received callout name and pkt4 value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_receive_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("pkt4_receive");

        callout_handle.getArgument("query4", callback_pkt4_);

        callback_argument_names_ = callout_handle.getArgumentNames();
        return (0);
    }

    /// test callback that changes client-id value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_receive_change_clientid(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("query4", pkt);

        // get rid of the old client-id
        pkt->delOption(DHO_DHCP_CLIENT_IDENTIFIER);

        // add a new option
        pkt->addOption(createOption(DHO_DHCP_CLIENT_IDENTIFIER));

        // carry on as usual
        return pkt4_receive_callout(callout_handle);
    }

    /// test callback that deletes client-id
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_receive_delete_clientid(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("query4", pkt);

        // get rid of the old client-id (and no HWADDR)
        vector<uint8_t> mac;
        pkt->delOption(DHO_DHCP_CLIENT_IDENTIFIER);
        pkt->setHWAddr(1, 0, mac); // HWtype 1, hardware len = 0

        // carry on as usual
        return pkt4_receive_callout(callout_handle);
    }

    /// test callback that sets skip flag
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_receive_skip(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("query4", pkt);

        callout_handle.setStatus(CalloutHandle::NEXT_STEP_SKIP);

        // carry on as usual
        return pkt4_receive_callout(callout_handle);
    }

    /// Test callback that stores received callout name and pkt4 value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_send_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("pkt4_send");

        callout_handle.getArgument("response4", callback_pkt4_);

        callout_handle.getArgument("query4", callback_pkt4_query_);

        callback_argument_names_ = callout_handle.getArgumentNames();
        return (0);
    }

    // Test callback that changes server-id
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_send_change_serverid(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("response4", pkt);

        // get rid of the old server-id
        pkt->delOption(DHO_DHCP_SERVER_IDENTIFIER);

        // add a new option
        pkt->addOption(createOption(DHO_DHCP_SERVER_IDENTIFIER));

        // carry on as usual
        return pkt4_send_callout(callout_handle);
    }

    /// test callback that deletes server-id
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_send_delete_serverid(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("response4", pkt);

        // get rid of the old client-id
        pkt->delOption(DHO_DHCP_SERVER_IDENTIFIER);

        // carry on as usual
        return pkt4_send_callout(callout_handle);
    }

    /// Test callback that sets skip flag
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    pkt4_send_skip(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("response4", pkt);

        callout_handle.setStatus(CalloutHandle::NEXT_STEP_SKIP);

        // carry on as usual
        return pkt4_send_callout(callout_handle);
    }

    /// Test callback that stores received callout name and pkt4 value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    buffer4_send_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("buffer4_send");

        callout_handle.getArgument("response4", callback_pkt4_);

        callback_argument_names_ = callout_handle.getArgumentNames();
        return (0);
    }

    /// Test callback changes the output buffer to a hardcoded value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    buffer4_send_change_callout(CalloutHandle& callout_handle) {

        Pkt4Ptr pkt;
        callout_handle.getArgument("response4", pkt);

        // modify buffer to set a different payload
        pkt->getBuffer().clear();
        pkt->getBuffer().writeData(dummyFile, sizeof(dummyFile));

        return (0);
    }

    /// Test callback that stores received callout name and pkt4 value
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    skip_callout(CalloutHandle& callout_handle) {

        callout_handle.setStatus(CalloutHandle::NEXT_STEP_SKIP);

        return (0);
    }

    /// Test callback that stores received callout name and subnet4 values
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    subnet4_select_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("subnet4_select");

        callout_handle.getArgument("query4", callback_pkt4_);
        callout_handle.getArgument("subnet4", callback_subnet4_);
        callout_handle.getArgument("subnet4collection", callback_subnet4collection_);

        callback_argument_names_ = callout_handle.getArgumentNames();
        return (0);
    }

    /// Test callback that picks the other subnet if possible.
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    subnet4_select_different_subnet_callout(CalloutHandle& callout_handle) {

        // Call the basic callout to record all passed values
        subnet4_select_callout(callout_handle);

        const Subnet4Collection* subnets;
        Subnet4Ptr subnet;
        callout_handle.getArgument("subnet4", subnet);
        callout_handle.getArgument("subnet4collection", subnets);

        // Let's change to a different subnet
        if (subnets->size() > 1) {
            subnet = (*subnets)[1]; // Let's pick the other subnet
            callout_handle.setArgument("subnet4", subnet);
        }

        return (0);
    }

    /// Test callback that stores received callout name passed parameters
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    lease4_release_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("lease4_release");

        callout_handle.getArgument("query4", callback_pkt4_);
        callout_handle.getArgument("lease4", callback_lease4_);

        callback_argument_names_ = callout_handle.getArgumentNames();
        return (0);
    }

    /// Test callback that stores received callout name and subnet4 values
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    lease4_renew_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("lease4_renew");

        callout_handle.getArgument("subnet4", callback_subnet4_);
        callout_handle.getArgument("lease4", callback_lease4_);
        callout_handle.getArgument("hwaddr", callback_hwaddr_);
        callout_handle.getArgument("clientid", callback_clientid_);

        callback_argument_names_ = callout_handle.getArgumentNames();
        return (0);
    }

    /// Test lease4_decline callback that stores received parameters.
    ///
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    lease4_decline_callout(CalloutHandle& callout_handle) {
        callback_name_ = string("lease4_decline");
        callout_handle.getArgument("query4", callback_pkt4_);
        callout_handle.getArgument("lease4", callback_lease4_);

        return (0);
    }

    /// Test lease4_decline callback that sets next step to DROP.
    ///
    /// @param callout_handle handle passed by the hooks framework
    /// @return always 0
    static int
    lease4_decline_drop_callout(CalloutHandle& callout_handle) {
        callout_handle.setStatus(CalloutHandle::NEXT_STEP_DROP);

        return (lease4_decline_callout(callout_handle));
    }

    /// resets buffers used to store data received by callouts
    void resetCalloutBuffers() {
        callback_name_ = string("");
        callback_pkt4_.reset();
        callback_pkt4_query_.reset();
        callback_lease4_.reset();
        callback_hwaddr_.reset();
        callback_clientid_.reset();
        callback_subnet4_.reset();
        callback_subnet4collection_ = NULL;
        callback_argument_names_.clear();
    }

    /// pointer to Dhcpv4Srv that is used in tests
    NakedDhcpv4Srv* srv_;

    // The following fields are used in testing pkt4_receive_callout

    /// String name of the received callout
    static string callback_name_;

    /// Pkt4 structure returned in the callout
    static Pkt4Ptr callback_pkt4_;

    /// @brief Pkt4 structure returned in the callout
    ///
    /// pkt4_send hook now passes both the query and the response,
    /// so we actually need two fields.
    static Pkt4Ptr callback_pkt4_query_;

    /// Lease4 structure returned in the callout
    static Lease4Ptr callback_lease4_;

    /// Hardware address returned in the callout
    static HWAddrPtr callback_hwaddr_;

    /// Client-id returned in the callout
    static ClientIdPtr callback_clientid_;

    /// Pointer to a subnet received by callout
    static Subnet4Ptr callback_subnet4_;

    /// A list of all available subnets (received by callout)
    static const Subnet4Collection* callback_subnet4collection_;

    /// A list of all received arguments
    static vector<string> callback_argument_names_;
};

// The following fields are used in testing pkt4_receive_callout.
// See fields description in the class for details
string HooksDhcpv4SrvTest::callback_name_;
Pkt4Ptr HooksDhcpv4SrvTest::callback_pkt4_;
Pkt4Ptr HooksDhcpv4SrvTest::callback_pkt4_query_;
Subnet4Ptr HooksDhcpv4SrvTest::callback_subnet4_;
HWAddrPtr HooksDhcpv4SrvTest::callback_hwaddr_;
ClientIdPtr HooksDhcpv4SrvTest::callback_clientid_;
Lease4Ptr HooksDhcpv4SrvTest::callback_lease4_;
const Subnet4Collection* HooksDhcpv4SrvTest::callback_subnet4collection_;
vector<string> HooksDhcpv4SrvTest::callback_argument_names_;

/// @brief Fixture class used to do basic library load/unload tests
class LoadUnloadDhcpv4SrvTest : public ::testing::Test {
public:
    /// @brief Pointer to the tested server object
    boost::shared_ptr<NakedDhcpv4Srv> server_;

    LoadUnloadDhcpv4SrvTest() {
        reset();
    }

    /// @brief Destructor
    ~LoadUnloadDhcpv4SrvTest() {
        server_.reset();
        reset();
    };

    /// @brief Reset hooks data
    ///
    /// Resets the data for the hooks-related portion of the test by ensuring
    /// that no libraries are loaded and that any marker files are deleted.
    void reset() {
        // Unload any previously-loaded libraries.
        HooksManager::unloadLibraries();

        // Get rid of any marker files.
        static_cast<void>(remove(LOAD_MARKER_FILE));
        static_cast<void>(remove(UNLOAD_MARKER_FILE));
        CfgMgr::instance().clear();
    }
};

// Checks if callouts installed on pkt4_receive are indeed called and the
// all necessary parameters are passed.
//
// Note that the test name does not follow test naming convention,
// but the proper hook name is "buffer4_receive".
TEST_F(HooksDhcpv4SrvTest, Buffer4ReceiveSimple) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "buffer4_receive", buffer4_receive_callout));

    // Let's create a simple DISCOVER
    Pkt4Ptr dis = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(dis);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered buffer4_receive callback.
    srv_->run();

    // Check that the callback called is indeed the one we installed
    EXPECT_EQ("buffer4_receive", callback_name_);

    // Check that pkt4 argument passing was successful and returned proper value
    EXPECT_TRUE(callback_pkt4_.get() == dis.get());

    // Check that all expected parameters are there
    vector<string> expected_argument_names;
    expected_argument_names.push_back(string("query4"));

    EXPECT_TRUE(expected_argument_names == callback_argument_names_);
}

// Checks if callouts installed on buffer4_receive is able to change
// the values and the parameters are indeed used by the server.
TEST_F(HooksDhcpv4SrvTest, buffer4ReceiveValueChange) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install callback that modifies MAC addr of incoming packet
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "buffer4_receive", buffer4_receive_change_hwaddr));

    // Let's create a simple DISCOVER
    Pkt4Ptr discover = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(discover);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive6(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered buffer4_receive callback.
    srv_->run();

    // Check that the server did send a response
    ASSERT_EQ(1, srv_->fake_sent_.size());

    // Make sure that we received a response
    Pkt4Ptr offer = srv_->fake_sent_.front();
    ASSERT_TRUE(offer);

    // Get client-id...
    HWAddrPtr hwaddr = offer->getHWAddr();

    ASSERT_TRUE(hwaddr); // basic sanity check. HWAddr is always present

    // ... and check if it is the modified value
    ASSERT_FALSE(hwaddr->hwaddr_.empty()); // there must be a MAC address
    EXPECT_EQ(0xff, hwaddr->hwaddr_[0]); // check that its first byte was modified
}

// Checks if callouts installed on buffer4_receive is able to set skip flag that
// will cause the server to not parse the packet. Even though the packet is valid,
// the server should eventually drop it, because there won't be mandatory options
// (or rather option objects) in it.
TEST_F(HooksDhcpv4SrvTest, buffer4ReceiveSkip) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "buffer4_receive", buffer4_receive_skip));

    // Let's create a simple DISCOVER
    Pkt4Ptr discover = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(discover);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive6(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // Check that the server dropped the packet and did not produce any response
    ASSERT_EQ(0, srv_->fake_sent_.size());
}

// Checks if callouts installed on pkt4_receive are indeed called and the
// all necessary parameters are passed.
//
// Note that the test name does not follow test naming convention,
// but the proper hook name is "pkt4_receive".
TEST_F(HooksDhcpv4SrvTest, pkt4ReceiveSimple) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_receive", pkt4_receive_callout));

    // Let's create a simple DISCOVER
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // check that the callback called is indeed the one we installed
    EXPECT_EQ("pkt4_receive", callback_name_);

    // check that pkt4 argument passing was successful and returned proper value
    EXPECT_TRUE(callback_pkt4_.get() == sol.get());

    // Check that all expected parameters are there
    vector<string> expected_argument_names;
    expected_argument_names.push_back(string("query4"));

    EXPECT_TRUE(expected_argument_names == callback_argument_names_);
}

// Checks if callouts installed on pkt4_received is able to change
// the values and the parameters are indeed used by the server.
TEST_F(HooksDhcpv4SrvTest, valueChange_pkt4_receive) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_receive", pkt4_receive_change_clientid));

    // Let's create a simple DISCOVER
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // check that the server did send a response
    ASSERT_EQ(1, srv_->fake_sent_.size());

    // Make sure that we received a response
    Pkt4Ptr adv = srv_->fake_sent_.front();
    ASSERT_TRUE(adv);

    // Get client-id...
    OptionPtr clientid = adv->getOption(DHO_DHCP_CLIENT_IDENTIFIER);

    // ... and check if it is the modified value
    OptionPtr expected = createOption(DHO_DHCP_CLIENT_IDENTIFIER);
    EXPECT_TRUE(clientid->equals(expected));
}

// Checks if callouts installed on pkt4_received is able to delete
// existing options and that change impacts server processing (mandatory
// client-id option is deleted, so the packet is expected to be dropped)
TEST_F(HooksDhcpv4SrvTest, pkt4ReceiveDeleteClientId) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_receive", pkt4_receive_delete_clientid));

    // Let's create a simple DISCOVER
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // Check that the server dropped the packet and did not send a response
    ASSERT_EQ(0, srv_->fake_sent_.size());
}

// Checks if callouts installed on pkt4_received is able to set skip flag that
// will cause the server to not process the packet (drop), even though it is valid.
TEST_F(HooksDhcpv4SrvTest, pkt4ReceiveSkip) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_receive", pkt4_receive_skip));

    // Let's create a simple DISCOVER
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // check that the server dropped the packet and did not produce any response
    ASSERT_EQ(0, srv_->fake_sent_.size());
}


// Checks if callouts installed on pkt4_send are indeed called and the
// all necessary parameters are passed.
TEST_F(HooksDhcpv4SrvTest, pkt4SendSimple) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_send", pkt4_send_callout));

    // Let's create a simple DISCOVER
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // Check that the callback called is indeed the one we installed
    EXPECT_EQ("pkt4_send", callback_name_);

    // Check that there is one packet sent
    ASSERT_EQ(1, srv_->fake_sent_.size());
    Pkt4Ptr adv = srv_->fake_sent_.front();

    // Check that pkt4 argument passing was successful and returned proper value
    ASSERT_TRUE(callback_pkt4_);
    EXPECT_TRUE(callback_pkt4_.get() == adv.get());

    // That that the query4 argument was correctly set to the Discover we sent.
    ASSERT_TRUE(callback_pkt4_query_);
    EXPECT_TRUE(callback_pkt4_query_.get() == sol.get());

    // Check that all expected parameters are there
    vector<string> expected_argument_names;
    expected_argument_names.push_back(string("response4"));
    expected_argument_names.push_back(string("query4"));
    sort(callback_argument_names_.begin(), callback_argument_names_.end());
    sort(expected_argument_names.begin(), expected_argument_names.end());
    EXPECT_TRUE(expected_argument_names == callback_argument_names_);
}

// Checks if callouts installed on pkt4_send is able to change
// the values and the packet sent contains those changes
TEST_F(HooksDhcpv4SrvTest, pkt4SendValueChange) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_send", pkt4_send_change_serverid));

    // Let's create a simple DISCOVER
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // check that the server did send a response
    ASSERT_EQ(1, srv_->fake_sent_.size());

    // Make sure that we received a response
    Pkt4Ptr adv = srv_->fake_sent_.front();
    ASSERT_TRUE(adv);

    // Get client-id...
    OptionPtr clientid = adv->getOption(DHO_DHCP_SERVER_IDENTIFIER);

    // ... and check if it is the modified value
    OptionPtr expected = createOption(DHO_DHCP_SERVER_IDENTIFIER);
    EXPECT_TRUE(clientid->equals(expected));
}

// Checks if callouts installed on pkt4_send is able to delete
// existing options and that server applies those changes. In particular,
// we are trying to send a packet without server-id. The packet should
// be sent
TEST_F(HooksDhcpv4SrvTest, pkt4SendDeleteServerId) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_send", pkt4_send_delete_serverid));

    // Let's create a simple DISCOVER
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // Check that the server indeed sent a malformed ADVERTISE
    ASSERT_EQ(1, srv_->fake_sent_.size());

    // Get that ADVERTISE
    Pkt4Ptr adv = srv_->fake_sent_.front();
    ASSERT_TRUE(adv);

    // Make sure that it does not have server-id
    EXPECT_FALSE(adv->getOption(DHO_DHCP_SERVER_IDENTIFIER));
}

// Checks if callouts installed on pkt4_skip is able to set skip flag that
// will cause the server to not process the packet (drop), even though it is valid.
TEST_F(HooksDhcpv4SrvTest, skip_pkt4_send) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "pkt4_send", pkt4_send_skip));

    // Let's create a simple REQUEST
    Pkt4Ptr sol = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(sol);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_send callback.
    srv_->run();

    // Check that the server sent the message
    ASSERT_EQ(1, srv_->fake_sent_.size());

    // Get the first packet and check that it has zero length (i.e. the server
    // did not do packing on its own)
    Pkt4Ptr sent = srv_->fake_sent_.front();
    EXPECT_EQ(0, sent->getBuffer().getLength());
}

// Checks if callouts installed on buffer4_send are indeed called and the
// all necessary parameters are passed.
TEST_F(HooksDhcpv4SrvTest, buffer4SendSimple) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "buffer4_send", buffer4_send_callout));

    // Let's create a simple DISCOVER
    Pkt4Ptr discover = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(discover);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // Check that the callback called is indeed the one we installed
    EXPECT_EQ("buffer4_send", callback_name_);

    // Check that there is one packet sent
    ASSERT_EQ(1, srv_->fake_sent_.size());
    Pkt4Ptr adv = srv_->fake_sent_.front();

    // Check that pkt4 argument passing was successful and returned proper value
    EXPECT_TRUE(callback_pkt4_.get() == adv.get());

    // Check that all expected parameters are there
    vector<string> expected_argument_names;
    expected_argument_names.push_back(string("response4"));
    EXPECT_TRUE(expected_argument_names == callback_argument_names_);
}

// Checks if callouts installed on buffer4_send are indeed called and that
// the output buffer can be changed.
TEST_F(HooksDhcpv4SrvTest, buffer4Send) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "buffer4_send", buffer4_send_change_callout));

    // Let's create a simple DISCOVER
    Pkt4Ptr discover = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(discover);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // Check that there is one packet sent
    ASSERT_EQ(1, srv_->fake_sent_.size());
    Pkt4Ptr adv = srv_->fake_sent_.front();

    // The callout is supposed to fill the output buffer with dummyFile content
    ASSERT_EQ(sizeof(dummyFile), adv->getBuffer().getLength());
    EXPECT_EQ(0, memcmp(adv->getBuffer().getData(), dummyFile, sizeof(dummyFile)));
}

// Checks if callouts installed on buffer4_send can set skip flag and that flag
// causes the packet to not be sent
TEST_F(HooksDhcpv4SrvTest, buffer4SendSkip) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "buffer4_send", skip_callout));

    // Let's create a simple DISCOVER
    Pkt4Ptr discover = generateSimpleDiscover();

    // Simulate that we have received that traffic
    srv_->fakeReceive(discover);

    // Server will now process to run its normal loop, but instead of calling
    // IfaceMgr::receive4(), it will read all packets from the list set by
    // fakeReceive()
    // In particular, it should call registered pkt4_receive callback.
    srv_->run();

    // Check that there is no packet sent.
    ASSERT_EQ(0, srv_->fake_sent_.size());
}


// This test checks if subnet4_select callout is triggered and reports
// valid parameters
TEST_F(HooksDhcpv4SrvTest, subnet4SelectSimple) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install pkt4_receive_callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "subnet4_select", subnet4_select_callout));

    // Configure 2 subnets, both directly reachable over local interface
    // (let's not complicate the matter with relays)
    string config = "{ \"interfaces-config\": {"
        "    \"interfaces\": [ \"*\" ]"
        "},"
        "\"rebind-timer\": 2000, "
        "\"renew-timer\": 1000, "
        "\"subnet4\": [ { "
        "    \"pools\": [ { \"pool\": \"192.0.2.0/25\" } ],"
        "    \"subnet\": \"192.0.2.0/24\", "
        "    \"interface\": \"eth0\" "
        " }, {"
        "    \"pools\": [ { \"pool\": \"192.0.3.0/25\" } ],"
        "    \"subnet\": \"192.0.3.0/24\" "
        " } ],"
        "\"valid-lifetime\": 4000 }";

    ElementPtr json = Element::fromJSON(config);
    ConstElementPtr status;

    // Configure the server and make sure the config is accepted
    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_, json));
    ASSERT_TRUE(status);
    comment_ = parseAnswer(rcode_, status);
    ASSERT_EQ(0, rcode_);

    // Commit the config
    CfgMgr::instance().commit();

    // Prepare discover packet. Server should select first subnet for it
    Pkt4Ptr sol = Pkt4Ptr(new Pkt4(DHCPDISCOVER, 1234));
    sol->setRemoteAddr(IOAddress("192.0.2.1"));
    sol->setIface("eth1");
    OptionPtr clientid = generateClientId();
    sol->addOption(clientid);

    // Pass it to the server and get an advertise
    Pkt4Ptr adv = srv_->processDiscover(sol);

    // check if we get response at all
    ASSERT_TRUE(adv);

    // Check that the callback called is indeed the one we installed
    EXPECT_EQ("subnet4_select", callback_name_);

    // Check that pkt4 argument passing was successful and returned proper value
    EXPECT_TRUE(callback_pkt4_.get() == sol.get());

    const Subnet4Collection* exp_subnets =
        CfgMgr::instance().getCurrentCfg()->getCfgSubnets4()->getAll();

    // The server is supposed to pick the first subnet, because of matching
    // interface. Check that the value is reported properly.
    ASSERT_TRUE(callback_subnet4_);
    EXPECT_EQ(exp_subnets->front().get(), callback_subnet4_.get());

    // Server is supposed to report two subnets
    ASSERT_EQ(exp_subnets->size(), callback_subnet4collection_->size());
    ASSERT_GE(exp_subnets->size(), 2);

    // Compare that the available subnets are reported as expected
    EXPECT_TRUE((*exp_subnets)[0].get() == (*callback_subnet4collection_)[0].get());
    EXPECT_TRUE((*exp_subnets)[1].get() == (*callback_subnet4collection_)[1].get());
}

// This test checks if callout installed on subnet4_select hook point can pick
// a different subnet.
TEST_F(HooksDhcpv4SrvTest, subnet4SelectChange) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install a callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "subnet4_select", subnet4_select_different_subnet_callout));

    // Configure 2 subnets, both directly reachable over local interface
    // (let's not complicate the matter with relays)
    string config = "{ \"interfaces-config\": {"
        "    \"interfaces\": [ \"*\" ]"
        "},"
        "\"rebind-timer\": 2000, "
        "\"renew-timer\": 1000, "
        "\"subnet4\": [ { "
        "    \"pools\": [ { \"pool\": \"192.0.2.0/25\" } ],"
        "    \"subnet\": \"192.0.2.0/24\", "
        "    \"interface\": \"eth0\" "
        " }, {"
        "    \"pools\": [ { \"pool\": \"192.0.3.0/25\" } ],"
        "    \"subnet\": \"192.0.3.0/24\" "
        " } ],"
        "\"valid-lifetime\": 4000 }";

    ElementPtr json = Element::fromJSON(config);
    ConstElementPtr status;

    // Configure the server and make sure the config is accepted
    EXPECT_NO_THROW(status = configureDhcp4Server(*srv_, json));
    ASSERT_TRUE(status);
    comment_ = parseAnswer(rcode_, status);
    ASSERT_EQ(0, rcode_);

    CfgMgr::instance().commit();

    // Prepare discover packet. Server should select first subnet for it
    Pkt4Ptr sol = Pkt4Ptr(new Pkt4(DHCPDISCOVER, 1234));
    sol->setRemoteAddr(IOAddress("192.0.2.1"));
    sol->setIface("eth0");
    OptionPtr clientid = generateClientId();
    sol->addOption(clientid);

    // Pass it to the server and get an advertise
    Pkt4Ptr adv = srv_->processDiscover(sol);

    // check if we get response at all
    ASSERT_TRUE(adv);

    // The response should have an address from second pool, so let's check it
    IOAddress addr = adv->getYiaddr();
    EXPECT_NE("0.0.0.0", addr.toText());

    // Get all subnets and use second subnet for verification
    const Subnet4Collection* subnets =
        CfgMgr::instance().getCurrentCfg()->getCfgSubnets4()->getAll();
    ASSERT_EQ(2, subnets->size());

    // Advertised address must belong to the second pool (in subnet's range,
    // in dynamic pool)
    EXPECT_TRUE((*subnets)[1]->inRange(addr));
    EXPECT_TRUE((*subnets)[1]->inPool(Lease::TYPE_V4, addr));
}

// This test verifies that incoming (positive) REQUEST/Renewing can be handled
// properly and that callout installed on lease4_renew is triggered with
// expected parameters.
TEST_F(HooksDhcpv4SrvTest, lease4RenewSimple) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    const IOAddress addr("192.0.2.106");
    const uint32_t temp_t1 = 50;
    const uint32_t temp_t2 = 75;
    const uint32_t temp_valid = 100;
    const time_t temp_timestamp = time(NULL) - 10;

    // Install a callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "lease4_renew", lease4_renew_callout));

    // Generate client-id also sets client_id_ member
    OptionPtr clientid = generateClientId();

    // Check that the address we are about to use is indeed in pool
    ASSERT_TRUE(subnet_->inPool(Lease::TYPE_V4, addr));

    // let's create a lease and put it in the LeaseMgr
    uint8_t hwaddr2_data[] = { 0, 0xfe, 0xfe, 0xfe, 0xfe, 0xfe};
    HWAddrPtr hwaddr2(new HWAddr(hwaddr2_data, sizeof(hwaddr2_data), HTYPE_ETHER));
    Lease4Ptr used(new Lease4(IOAddress("192.0.2.106"), hwaddr2,
                              &client_id_->getDuid()[0], client_id_->getDuid().size(),
                              temp_valid, temp_t1, temp_t2, temp_timestamp,
                              subnet_->getID()));
    ASSERT_TRUE(LeaseMgrFactory::instance().addLease(used));

    // Check that the lease is really in the database
    Lease4Ptr l = LeaseMgrFactory::instance().getLease4(addr);
    ASSERT_TRUE(l);

    // Let's create a RENEW
    Pkt4Ptr req = Pkt4Ptr(new Pkt4(DHCPREQUEST, 1234));
    req->setRemoteAddr(IOAddress(addr));
    req->setYiaddr(addr);
    req->setCiaddr(addr); // client's address
    req->setIface("eth0");
    req->setHWAddr(hwaddr2);

    req->addOption(clientid);
    req->addOption(srv_->getServerID());

    // Pass it to the server and hope for a REPLY
    Pkt4Ptr ack = srv_->processRequest(req);

    // Check if we get response at all
    checkResponse(ack, DHCPACK, 1234);

    // Check that the lease is really in the database
    l = checkLease(ack, clientid, req->getHWAddr(), addr);
    ASSERT_TRUE(l);

    // Check that T1, T2, preferred, valid and cltt were really updated
    EXPECT_EQ(l->t1_, subnet_->getT1());
    EXPECT_EQ(l->t2_, subnet_->getT2());
    EXPECT_EQ(l->valid_lft_, subnet_->getValid());

    // Check that the callback called is indeed the one we installed
    EXPECT_EQ("lease4_renew", callback_name_);

    // Check that hwaddr parameter is passed properly
    ASSERT_TRUE(callback_hwaddr_);
    EXPECT_TRUE(*callback_hwaddr_ == *req->getHWAddr());

    // Check that the subnet is passed properly
    ASSERT_TRUE(callback_subnet4_);
    EXPECT_EQ(callback_subnet4_->toText(), subnet_->toText());

    ASSERT_TRUE(callback_clientid_);
    ASSERT_TRUE(client_id_);
    EXPECT_TRUE(*client_id_ == *callback_clientid_);

    // Check if all expected parameters were really received
    vector<string> expected_argument_names;
    expected_argument_names.push_back("subnet4");
    expected_argument_names.push_back("clientid");
    expected_argument_names.push_back("hwaddr");
    expected_argument_names.push_back("lease4");
    sort(callback_argument_names_.begin(), callback_argument_names_.end());
    sort(expected_argument_names.begin(), expected_argument_names.end());
    EXPECT_TRUE(callback_argument_names_ == expected_argument_names);

    EXPECT_TRUE(LeaseMgrFactory::instance().deleteLease(addr));
}

// This test verifies that a callout installed on lease4_renew can trigger
// the server to not renew a lease.
TEST_F(HooksDhcpv4SrvTest, lease4RenewSkip) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    const IOAddress addr("192.0.2.106");
    const uint32_t temp_t1 = 50;
    const uint32_t temp_t2 = 75;
    const uint32_t temp_valid = 100;
    const time_t temp_timestamp = time(NULL) - 10;

    // Install a callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "lease4_renew", skip_callout));

    // Generate client-id also sets client_id_ member
    OptionPtr clientid = generateClientId();

    // Check that the address we are about to use is indeed in pool
    ASSERT_TRUE(subnet_->inPool(Lease::TYPE_V4, addr));

    // let's create a lease and put it in the LeaseMgr
    uint8_t hwaddr2_data[] = { 0, 0xfe, 0xfe, 0xfe, 0xfe, 0xfe};
    HWAddrPtr hwaddr2(new HWAddr(hwaddr2_data, sizeof(hwaddr2_data), HTYPE_ETHER));
    Lease4Ptr used(new Lease4(IOAddress("192.0.2.106"), hwaddr2,
                              &client_id_->getDuid()[0], client_id_->getDuid().size(),
                              temp_valid, temp_t1, temp_t2, temp_timestamp,
                              subnet_->getID()));
    ASSERT_TRUE(LeaseMgrFactory::instance().addLease(used));

    // Check that the lease is really in the database
    Lease4Ptr l = LeaseMgrFactory::instance().getLease4(addr);
    ASSERT_TRUE(l);

    // Check that T1, T2, preferred, valid and cltt really set.
    // Constructed lease looks as if it was assigned 10 seconds ago
    // EXPECT_EQ(l->t1_, temp_t1);
    // EXPECT_EQ(l->t2_, temp_t2);
    EXPECT_EQ(l->valid_lft_, temp_valid);
    EXPECT_EQ(l->cltt_, temp_timestamp);

    // Let's create a RENEW
    Pkt4Ptr req = Pkt4Ptr(new Pkt4(DHCPREQUEST, 1234));
    req->setRemoteAddr(IOAddress(addr));
    req->setYiaddr(addr);
    req->setCiaddr(addr); // client's address
    req->setIface("eth0");
    req->setHWAddr(hwaddr2);

    req->addOption(clientid);
    req->addOption(srv_->getServerID());

    // Pass it to the server and hope for a REPLY
    Pkt4Ptr ack = srv_->processRequest(req);
    ASSERT_TRUE(ack);

    // Check that the lease is really in the database
    l = checkLease(ack, clientid, req->getHWAddr(), addr);
    ASSERT_TRUE(l);

    // Check that T1, T2, valid and cltt were NOT updated
    EXPECT_EQ(temp_t1, l->t1_);
    EXPECT_EQ(temp_t2, l->t2_);
    EXPECT_EQ(temp_valid, l->valid_lft_);
    EXPECT_EQ(temp_timestamp, l->cltt_);

    EXPECT_TRUE(LeaseMgrFactory::instance().deleteLease(addr));
}

// This test verifies that valid RELEASE triggers lease4_release callouts
TEST_F(HooksDhcpv4SrvTest, lease4ReleaseSimple) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    const IOAddress addr("192.0.2.106");
    const uint32_t temp_t1 = 50;
    const uint32_t temp_t2 = 75;
    const uint32_t temp_valid = 100;
    const time_t temp_timestamp = time(NULL) - 10;

    // Install a callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "lease4_release", lease4_release_callout));

    // Generate client-id also duid_
    OptionPtr clientid = generateClientId();

    // Check that the address we are about to use is indeed in pool
    ASSERT_TRUE(subnet_->inPool(Lease::TYPE_V4, addr));

    // Let's create a lease and put it in the LeaseMgr
    uint8_t mac_addr[] = { 0, 0xfe, 0xfe, 0xfe, 0xfe, 0xfe};
    HWAddrPtr hw(new HWAddr(mac_addr, sizeof(mac_addr), HTYPE_ETHER));
    Lease4Ptr used(new Lease4(addr, hw,
                              &client_id_->getDuid()[0], client_id_->getDuid().size(),
                              temp_valid, temp_t1, temp_t2, temp_timestamp,
                              subnet_->getID()));
    ASSERT_TRUE(LeaseMgrFactory::instance().addLease(used));

    // Check that the lease is really in the database
    Lease4Ptr l = LeaseMgrFactory::instance().getLease4(addr);
    ASSERT_TRUE(l);

    // Let's create a RELEASE
    // Generate client-id also duid_
    Pkt4Ptr rel = Pkt4Ptr(new Pkt4(DHCPRELEASE, 1234));
    rel->setRemoteAddr(addr);
    rel->setCiaddr(addr);
    rel->addOption(clientid);
    rel->addOption(srv_->getServerID());
    rel->setHWAddr(hw);

    // Pass it to the server and hope for a REPLY
    // Note: this is no response to RELEASE in DHCPv4
    EXPECT_NO_THROW(srv_->processRelease(rel));

    // The lease should be gone from LeaseMgr
    l = LeaseMgrFactory::instance().getLease4(addr);
    EXPECT_FALSE(l);

    // Try to get the lease by hardware address
    // @todo: Uncomment this once trac2592 is implemented
    // Lease4Collection leases = LeaseMgrFactory::instance().getLease4(hw->hwaddr_);
    // EXPECT_EQ(leases.size(), 0);

    // Try to get it by hw/subnet_id combination
    l = LeaseMgrFactory::instance().getLease4(hw->hwaddr_, subnet_->getID());
    EXPECT_FALSE(l);

    // Try by client-id
    // @todo: Uncomment this once trac2592 is implemented
    //Lease4Collection leases = LeaseMgrFactory::instance().getLease4(*client_id_);
    //EXPECT_EQ(leases.size(), 0);

    // Try by client-id/subnet-id
    l = LeaseMgrFactory::instance().getLease4(*client_id_, subnet_->getID());
    EXPECT_FALSE(l);

    // Ok, the lease is *really* not there.

    // Check that the callback called is indeed the one we installed
    EXPECT_EQ("lease4_release", callback_name_);

    // Check that pkt4 argument passing was successful and returned proper value
    EXPECT_TRUE(callback_pkt4_.get() == rel.get());

    // Check if all expected parameters were really received
    vector<string> expected_argument_names;
    expected_argument_names.push_back("query4");
    expected_argument_names.push_back("lease4");
    sort(callback_argument_names_.begin(), callback_argument_names_.end());
    sort(expected_argument_names.begin(), expected_argument_names.end());
    EXPECT_TRUE(callback_argument_names_ == expected_argument_names);
}

// This test verifies that skip flag returned by a callout installed on the
// lease4_release hook point will keep the lease
TEST_F(HooksDhcpv4SrvTest, lease4ReleaseSkip) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    const IOAddress addr("192.0.2.106");
    const uint32_t temp_t1 = 50;
    const uint32_t temp_t2 = 75;
    const uint32_t temp_valid = 100;
    const time_t temp_timestamp = time(NULL) - 10;

    // Install a callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "lease4_release", skip_callout));

    // Generate client-id also duid_
    OptionPtr clientid = generateClientId();

    // Check that the address we are about to use is indeed in pool
    ASSERT_TRUE(subnet_->inPool(Lease::TYPE_V4, addr));

    // Let's create a lease and put it in the LeaseMgr
    uint8_t mac_addr[] = { 0, 0xfe, 0xfe, 0xfe, 0xfe, 0xfe};
    HWAddrPtr hw(new HWAddr(mac_addr, sizeof(mac_addr), HTYPE_ETHER));
    Lease4Ptr used(new Lease4(addr, hw,
                              &client_id_->getDuid()[0], client_id_->getDuid().size(),
                              temp_valid, temp_t1, temp_t2, temp_timestamp,
                              subnet_->getID()));
    ASSERT_TRUE(LeaseMgrFactory::instance().addLease(used));

    // Check that the lease is really in the database
    Lease4Ptr l = LeaseMgrFactory::instance().getLease4(addr);
    ASSERT_TRUE(l);

    // Let's create a RELEASE
    // Generate client-id also duid_
    Pkt4Ptr rel = Pkt4Ptr(new Pkt4(DHCPRELEASE, 1234));
    rel->setRemoteAddr(addr);
    rel->setYiaddr(addr);
    rel->addOption(clientid);
    rel->addOption(srv_->getServerID());
    rel->setHWAddr(hw);

    // Pass it to the server and hope for a REPLY
    // Note: this is no response to RELEASE in DHCPv4
    EXPECT_NO_THROW(srv_->processRelease(rel));

    // The lease should be still there
    l = LeaseMgrFactory::instance().getLease4(addr);
    EXPECT_TRUE(l);

    // Try by client-id/subnet-id
    l = LeaseMgrFactory::instance().getLease4(*client_id_, subnet_->getID());
    EXPECT_TRUE(l);

    // Try to get the lease by hardware address, should succeed
    Lease4Collection leases = LeaseMgrFactory::instance().getLease4(*hw);
    EXPECT_EQ(leases.size(), 1);

    // Try by client-id, should be successful as well.
    leases = LeaseMgrFactory::instance().getLease4(*client_id_);
    EXPECT_EQ(leases.size(), 1);
}

// Checks that decline4 hooks (lease4_decline) are triggered properly.
TEST_F(HooksDhcpv4SrvTest, HooksDecline) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install a callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "lease4_decline", lease4_decline_callout));

    // Conduct the actual DORA + Decline.
    Dhcp4Client client(Dhcp4Client::SELECTING);
    acquireAndDecline(client, "01:02:03:04:05:06", "12:14",
                      "01:02:03:04:05:06", "12:14",
                      SHOULD_PASS);

    EXPECT_EQ("lease4_decline", callback_name_);

    // Verifying DHCPDECLINE is a bit tricky, as it is created somewhere in
    // acquireAndDecline. We'll just verify that it's really a DECLINE
    // and that its address is equal to what we have in LeaseMgr.
    ASSERT_TRUE(callback_pkt4_);
    ASSERT_TRUE(callback_lease4_);

    // Check that it's the proper packet that was reported.
    EXPECT_EQ(DHCPDECLINE, callback_pkt4_->getType());

    // Extract the address being declined.
    OptionCustomPtr opt_declined_addr = boost::dynamic_pointer_cast<
        OptionCustom>(callback_pkt4_->getOption(DHO_DHCP_REQUESTED_ADDRESS));
    ASSERT_TRUE(opt_declined_addr);
    IOAddress addr(opt_declined_addr->readAddress());

    // And try to get a matching lease from the lease manager.
    Lease4Ptr from_mgr = LeaseMgrFactory::instance().getLease4(addr);
    ASSERT_TRUE(from_mgr);
    EXPECT_EQ(Lease::STATE_DECLINED, from_mgr->state_);

    // Let's now check that those 3 things (packet, lease returned and lease from
    // the lease manager) all match.
    EXPECT_EQ(addr, from_mgr->addr_);
    EXPECT_EQ(addr, callback_lease4_->addr_);
}

// Checks that decline4 hook is able to drop the packet.
TEST_F(HooksDhcpv4SrvTest, HooksDeclineDrop) {
    IfaceMgrTestConfig test_config(true);
    IfaceMgr::instance().openSockets4();

    // Install a callout
    EXPECT_NO_THROW(HooksManager::preCalloutsLibraryHandle().registerCallout(
                        "lease4_decline", lease4_decline_drop_callout));

    // Conduct the actual DORA + Decline. The DECLINE should fail, as the
    // hook will set the status to DROP.
    Dhcp4Client client(Dhcp4Client::SELECTING);
    acquireAndDecline(client, "01:02:03:04:05:06", "12:14",
                      "01:02:03:04:05:06", "12:14",
                      SHOULD_FAIL);

    EXPECT_EQ("lease4_decline", callback_name_);

    // Verifying DHCPDECLINE is a bit tricky, as it is created somewhere in
    // acquireAndDecline. We'll just verify that it's really a DECLINE
    // and that its address is equal to what we have in LeaseMgr.
    ASSERT_TRUE(callback_pkt4_);
    ASSERT_TRUE(callback_lease4_);

    // Check that it's the proper packet that was reported.
    EXPECT_EQ(DHCPDECLINE, callback_pkt4_->getType());

    // Extract the address being declined.
    OptionCustomPtr opt_declined_addr = boost::dynamic_pointer_cast<
        OptionCustom>(callback_pkt4_->getOption(DHO_DHCP_REQUESTED_ADDRESS));
    ASSERT_TRUE(opt_declined_addr);
    IOAddress addr(opt_declined_addr->readAddress());

    // And try to get a matching lease from the lease manager. The lease should
    // still be there in default state, not in declined state.
    Lease4Ptr from_mgr = LeaseMgrFactory::instance().getLease4(addr);
    ASSERT_TRUE(from_mgr);
    EXPECT_EQ(Lease::STATE_DEFAULT, from_mgr->state_);

    // As a final sanity check, let's now check that those 3 things (packet,
    // lease returned and lease from the lease manager) all match.
    EXPECT_EQ(addr, from_mgr->addr_);
    EXPECT_EQ(addr, callback_lease4_->addr_);
}


// Verifies that libraries are unloaded by server destruction
// The callout libraries write their library index number to a marker
// file upon load and unload, making it simple to test whether or not
// the load and unload callouts have been invoked.
TEST_F(LoadUnloadDhcpv4SrvTest, unloadLibaries) {

    ASSERT_NO_THROW(server_.reset(new NakedDhcpv4Srv()));

    // Ensure no marker files to start with.
    ASSERT_FALSE(checkMarkerFileExists(LOAD_MARKER_FILE));
    ASSERT_FALSE(checkMarkerFileExists(UNLOAD_MARKER_FILE));

    // Load two libraries
    std::vector<std::string> libraries;
    libraries.push_back(CALLOUT_LIBRARY_1);
    libraries.push_back(CALLOUT_LIBRARY_2);
    HooksManager::loadLibraries(libraries);

    // Check they are loaded.
    std::vector<std::string> loaded_libraries =
        HooksManager::getLibraryNames();
    ASSERT_TRUE(libraries == loaded_libraries);

    // ... which also included checking that the marker file created by the
    // load functions exists and holds the correct value (of "12" - the
    // first library appends "1" to the file, the second appends "2"). Also
    // check that the unload marker file does not yet exist.
    EXPECT_TRUE(checkMarkerFile(LOAD_MARKER_FILE, "12"));
    EXPECT_FALSE(checkMarkerFileExists(UNLOAD_MARKER_FILE));

    server_.reset();

    // Check that the libraries have unloaded and reloaded.  The libraries are
    // unloaded in the reverse order to which they are loaded.  When they load,
    // they should append information to the loading marker file.
    EXPECT_TRUE(checkMarkerFile(UNLOAD_MARKER_FILE, "21"));
    EXPECT_TRUE(checkMarkerFile(LOAD_MARKER_FILE, "12"));
}