// Copyright (C) 2012-2023 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 <perfdhcp/command_options.h>

#include <asiolink/io_error.h>
#include <exceptions/exceptions.h>
#include <dhcp/iface_mgr.h>
#include <dhcp/duid.h>
#include <dhcp/option.h>
#include <process/cfgrpt/config_report.h>
#include <util/encode/hex.h>

#include <boost/lexical_cast.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
#include <sstream>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <fstream>
#include <thread>
#include <getopt.h>

#ifdef HAVE_OPTRESET
extern int optreset;
#endif

using namespace std;
using namespace isc;
using namespace isc::dhcp;

namespace isc {
namespace perfdhcp {

CommandOptions::LeaseType::LeaseType()
    : type_(ADDRESS) {
}

CommandOptions::LeaseType::LeaseType(const Type lease_type)
    : type_(lease_type) {
}

bool
CommandOptions::LeaseType::is(const Type lease_type) const {
    return (lease_type == type_);
}

bool
CommandOptions::LeaseType::includes(const Type lease_type) const {
    return (is(ADDRESS_AND_PREFIX) || (lease_type == type_));
}

void
CommandOptions::LeaseType::set(const Type lease_type) {
    type_ = lease_type;
}

void
CommandOptions::LeaseType::fromCommandLine(const std::string& cmd_line_arg) {
    if (cmd_line_arg == "address-only") {
        type_ = ADDRESS;

    } else if (cmd_line_arg == "prefix-only") {
        type_ = PREFIX;

    } else if (cmd_line_arg == "address-and-prefix") {
        type_ = ADDRESS_AND_PREFIX;

    } else {
        isc_throw(isc::InvalidParameter, "value of lease-type: -e<lease-type>,"
                  " must be one of the following: 'address-only' or"
                  " 'prefix-only'");
    }
}

std::string
CommandOptions::LeaseType::toText() const {
    switch (type_) {
    case ADDRESS:
        return ("address-only (IA_NA option added to the client's request)");
    case PREFIX:
        return ("prefix-only (IA_PD option added to the client's request)");
    case ADDRESS_AND_PREFIX:
        return ("address-and-prefix (Both IA_NA and IA_PD options added to the"
                " client's request)");
    default:
        isc_throw(Unexpected, "internal error: undefined lease type code when"
                  " returning textual representation of the lease type");
    }
}

void
CommandOptions::reset() {
    // Default mac address used in DHCP messages
    // if -b mac=<mac-address> was not specified
    uint8_t mac[6] = { 0x0, 0xC, 0x1, 0x2, 0x3, 0x4 };

    // Default packet drop time if -D<drop-time> parameter
    // was not specified
    double dt[2] = { 1., 1. };

    // We don't use constructor initialization list because we
    // will need to reset all members many times to perform unit tests
    ipversion_ = 0;
    exchange_mode_ = DORA_SARR;
    lease_type_.set(LeaseType::ADDRESS);
    rate_ = 0;
    renew_rate_ = 0;
    release_rate_ = 0;
    report_delay_ = 0;
    clean_report_ = false;
    clean_report_separator_ = "";
    clients_num_ = 0;
    mac_template_.assign(mac, mac + 6);
    duid_template_.clear();
    base_.clear();
    addr_unique_ = false;
    mac_list_file_.clear();
    mac_list_.clear();
    relay_addr_list_file_.clear();
    relay_addr_list_.clear();
    multi_subnet_ = false;
    num_request_.clear();
    exit_wait_time_ = 0;
    period_ = 0;
    wait_for_elapsed_time_ = -1;
    increased_elapsed_time_ = -1;
    drop_time_set_ = 0;
    drop_time_.assign(dt, dt + 2);
    max_drop_.clear();
    max_pdrop_.clear();
    localname_.clear();
    is_interface_ = false;
    preload_ = 0;
    local_port_ = 0;
    remote_port_ = 0;
    seeded_ = false;
    seed_ = 0;
    broadcast_ = false;
    rapid_commit_ = false;
    use_first_ = false;
    template_file_.clear();
    rnd_offset_.clear();
    xid_offset_.clear();
    elp_offset_ = -1;
    sid_offset_ = -1;
    rip_offset_ = -1;
    diags_.clear();
    wrapped_.clear();
    server_name_.clear();
    v6_relay_encapsulation_level_ = 0;
    generateDuidTemplate();
    extra_opts_.clear();
    if (std::thread::hardware_concurrency() == 1) {
        single_thread_mode_ = true;
    } else {
        single_thread_mode_ = false;
    }
    scenario_ = Scenario::BASIC;
    for (uint8_t i = 1; i <= RELAY_OPTIONS_MAX_ENCAPSULATION ; i++) {
        OptionCollection option_collection;
        relay_opts_[i] = option_collection;
    }
}

bool
CommandOptions::parse(int argc, char** const argv, bool print_cmd_line) {
    // Reset internal variables used by getopt
    // to eliminate undefined behavior when
    // parsing different command lines multiple times

#ifdef __GLIBC__
    // Warning: non-portable code. This is due to a bug in glibc's
    // getopt() which keeps internal state about an old argument vector
    // (argc, argv) from last call and tries to scan them when a new
    // argument vector (argc, argv) is passed. As the old vector may not
    // be main()'s arguments, but heap allocated and may have been freed
    // since, this becomes a use after free and results in random
    // behavior. According to the NOTES section in glibc getopt()'s
    // manpage, setting optind=0 resets getopt()'s state. Though this is
    // not required in our usage of getopt(), the bug still happens
    // unless we set optind=0.
    //
    // Setting optind=0 is non-portable code.
    optind = 0;
#else
    optind = 1;
#endif

    // optreset is declared on BSD systems and is used to reset internal
    // state of getopt(). When parsing command line arguments multiple
    // times with getopt() the optreset must be set to 1 every time before
    // parsing starts. Failing to do so will result in random behavior of
    // getopt().
#ifdef HAVE_OPTRESET
    optreset = 1;
#endif

    opterr = 0;

    // Reset values of class members
    reset();

    // Informs if program has been run with 'h' or 'v' option.
    bool help_or_version_mode = initialize(argc, argv, print_cmd_line);
    if (!help_or_version_mode) {
        validate();
    }
    return (help_or_version_mode);
}

const int LONG_OPT_SCENARIO = 300;
const int LONG_OPT_RELAY_OPTION = 400;

bool
CommandOptions::initialize(int argc, char** argv, bool print_cmd_line) {
    int opt = 0;                // Subsequent options returned by getopt()
    int opt_long_index = 0;     // Holds index of long_option inside of long_options[]
    std::string drop_arg;       // Value of -D<value>argument
    size_t percent_loc = 0;     // Location of % sign in -D<value>
    double drop_percent = 0;    // % value (1..100) in -D<value%>
    int num_drops = 0;          // Max number of drops specified in -D<value>
    int num_req = 0;            // Max number of dropped
                                // requests in -n<max-drops>
    int offset_arg = 0;         // Temporary variable holding offset arguments
    std::string sarg;           // Temporary variable for string args

    std::ostringstream stream;
    stream << "perfdhcp";
    int num_mac_list_files = 0;
    int num_subnet_list_files = 0;

    struct option long_options[] = {
        {"scenario", required_argument, 0, LONG_OPT_SCENARIO},
        {"or",       required_argument, 0, LONG_OPT_RELAY_OPTION},
        {0,          0,                 0, 0}
    };

    // In this section we collect argument values from command line
    // they will be tuned and validated elsewhere
    while((opt = getopt_long(argc, argv,
                             "huv46A:r:t:R:b:n:p:d:D:l:P:a:L:N:M:s:iBc1"
                             "J:T:X:O:o:E:S:I:x:W:w:e:f:F:g:C:y:Y:",
                             long_options, &opt_long_index)) != -1) {
        stream << " -";
        opt <= 'z' ? stream << static_cast<char>(opt) :
                     stream << "-" << long_options[opt_long_index].name;
        if (optarg) {
            stream << " " << optarg;
        }
        switch (opt) {
        case '1':
            use_first_ = true;
            break;

        // Simulate DHCPv6 relayed traffic.
        case 'A':
            // @todo: At the moment we only support simulating a single relay
            // agent. In the future we should extend it to up to 32.
            // See comment in https://github.com/isc-projects/kea/pull/22#issuecomment-243405600
            v6_relay_encapsulation_level_ =
                static_cast<uint8_t>(positiveInteger("-A<encapsulation-level> must"
                                                     " be a positive integer"));
            if (v6_relay_encapsulation_level_ != 1) {
                isc_throw(isc::InvalidParameter, "-A only supports 1 at the moment.");
            }
            break;

        case 'u':
            addr_unique_ = true;
            break;

        case '4':
            check(ipversion_ == 6, "IP version already set to 6");
            ipversion_ = 4;
            break;

        case '6':
            check(ipversion_ == 4, "IP version already set to 4");
            ipversion_ = 6;
            break;

        case 'b':
            check(base_.size() > 3, "-b<value> already specified,"
                  " unexpected occurrence of 5th -b<value>");
            base_.push_back(optarg ? optarg : "");
            decodeBase(base_.back());
            break;

        case 'B':
            broadcast_ = true;
            break;

        case 'c':
            rapid_commit_ = true;
            break;

        case 'C':
            clean_report_ = true;
            clean_report_separator_ = optarg ? optarg : "";
            break;

        case 'd':
            check(drop_time_set_ > 1,
                  "maximum number of drops already specified, "
                  "unexpected 3rd occurrence of -d<value>");
            try {
                drop_time_[drop_time_set_] =
                    boost::lexical_cast<double>(optarg ? optarg : "");
            } catch (const boost::bad_lexical_cast&) {
                isc_throw(isc::InvalidParameter,
                          "value of drop time: -d<value>"
                          " must be positive number");
            }
            check(drop_time_[drop_time_set_] <= 0.,
                  "drop-time must be a positive number");
            drop_time_set_ = true;
            break;

        case 'D':
            drop_arg = std::string(optarg ? optarg : "");
            percent_loc = drop_arg.find('%');
            check(max_pdrop_.size() > 1 || max_drop_.size() > 1,
                  "values of maximum drops: -D<value> already "
                  "specified, unexpected 3rd occurrence of -D<value>");
            if ((percent_loc) != std::string::npos) {
                try {
                    drop_percent =
                        boost::lexical_cast<double>(drop_arg.substr(0, percent_loc));
                } catch (const boost::bad_lexical_cast&) {
                    isc_throw(isc::InvalidParameter,
                              "value of drop percentage: -D<value%>"
                              " must be 0..100");
                }
                check((drop_percent <= 0) || (drop_percent >= 100),
                  "value of drop percentage: -D<value%> must be 0..100");
                max_pdrop_.push_back(drop_percent);
            } else {
                num_drops = positiveInteger("value of max drops number:"
                                            " -D<value> must be a positive integer");
                max_drop_.push_back(num_drops);
            }
            break;

        case 'e':
            initLeaseType();
            break;

        case 'E':
            elp_offset_ = nonNegativeInteger("value of time-offset: -E<value>"
                                             " must not be a negative integer");
            break;

        case 'f':
            renew_rate_ = positiveInteger("value of the renew rate: -f<renew-rate>"
                                          " must be a positive integer");
            break;

        case 'F':
            release_rate_ = positiveInteger("value of the release rate:"
                                            " -F<release-rate> must be a"
                                            " positive integer");
            break;

        case 'g': {
            std::string optarg_text(optarg ? optarg : "");
            if (optarg_text == "single") {
                single_thread_mode_ = true;
            } else if (optarg_text == "multi") {
                single_thread_mode_ = false;
            } else {
                if (optarg) {
                    isc_throw(InvalidParameter, "value of thread mode (-g) '" << optarg << "' is wrong - should be '-g single' or '-g multi'");
                } else {
                    isc_throw(InvalidParameter, "value of thread mode (-g) is wrong - should be '-g single' or '-g multi'");
                }
            }
            break;
        }
        case 'h':
            usage();
            return (true);

        case 'i':
            exchange_mode_ = DO_SA;
            break;

        case 'I':
            rip_offset_ = positiveInteger("value of ip address offset:"
                                          " -I<value> must be a"
                                          " positive integer");
            break;

        case 'J':
            check(num_subnet_list_files >= 1, "only one -J option can be specified");
            num_subnet_list_files++;
            relay_addr_list_file_ = std::string(optarg ? optarg : "");
            loadRelayAddr();
            break;

        case 'l':
            localname_ = std::string(optarg ? optarg : "");
            initIsInterface();
            break;

        case 'L':
             local_port_ = nonNegativeInteger("value of local port:"
                                              " -L<value> must not be a"
                                              " negative integer");
             check(local_port_ >
                   static_cast<int>(std::numeric_limits<uint16_t>::max()),
                   "local-port must be lower than " +
                   boost::lexical_cast<std::string>(std::numeric_limits<uint16_t>::max()));
            break;

        case 'N':
             remote_port_ = nonNegativeInteger("value of remote port:"
                                               " -L<value> must not be a"
                                               " negative integer");
             check(remote_port_ >
                   static_cast<int>(std::numeric_limits<uint16_t>::max()),
                   "remote-port must be lower than " +
                   boost::lexical_cast<std::string>(std::numeric_limits<uint16_t>::max()));
            break;

        case 'M':
            check(num_mac_list_files >= 1, "only one -M option can be specified");
            num_mac_list_files++;
            mac_list_file_ = std::string(optarg ? optarg : "");
            loadMacs();
            break;

        case 'W':
            exit_wait_time_ = nonNegativeInteger("value of exist wait time: "
                                                  "-W<value> must not be a "
                                                  "negative integer");
            break;

        case 'n':
            num_req = positiveInteger("value of num-request:"
                                      " -n<value> must be a positive integer");
            if (num_request_.size() >= 2) {
                isc_throw(isc::InvalidParameter,
                          "value of maximum number of requests: -n<value> "
                          "already specified, unexpected 3rd occurrence"
                          " of -n<value>");
            }
            num_request_.push_back(num_req);
            break;

        case 'O':
            if (rnd_offset_.size() < 2) {
                offset_arg = positiveInteger("value of random offset: "
                                             "-O<value> must be greater than 3");
            } else {
                isc_throw(isc::InvalidParameter,
                          "random offsets already specified,"
                          " unexpected 3rd occurrence of -O<value>");
            }
            check(offset_arg < 3, "value of random random-offset:"
                  " -O<value> must be greater than 3 ");
            rnd_offset_.push_back(offset_arg);
            break;
        case 'o': {

            // we must know how to contruct the option: whether it's v4 or v6.
            check( (ipversion_ != 4) && (ipversion_ != 6),
                   "-4 or -6 must be explicitly specified before -o is used.");

            // custom option (expected format: code,hexstring)
            std::string opt_text(optarg ? optarg : "");
            size_t comma_loc = opt_text.find(',');
            check(comma_loc == std::string::npos,
                  "-o option must provide option code, a comma and hexstring for"
                  " the option content, e.g. -o60,646f63736973 for sending option"
                  " 60 (class-id) with the value 'docsis'");
            int code = 0;

            // Try to parse the option code
            try {
                code = boost::lexical_cast<int>(opt_text.substr(0, comma_loc));
                check(code <= 0, "Option code can't be negative");
            } catch (const boost::bad_lexical_cast&) {
                isc_throw(InvalidParameter, "Invalid option code specified for "
                          "-o option, expected format: -o<integer>,<hexstring>");
            }

            // Now try to interpret the hexstring
            opt_text = opt_text.substr(comma_loc + 1);
            std::vector<uint8_t> bin;
            try {
                isc::util::encode::decodeHex(opt_text, bin);
            } catch (const BadValue& e) {
                isc_throw(InvalidParameter, "Error during encoding option -o:"
                          << e.what());
            }

            // Create and remember the option.
            OptionPtr opt(new Option(ipversion_ == 4 ? Option::V4 : Option::V6,
                                     code, bin));
            extra_opts_.insert(make_pair(code, opt));
            break;
        }
        case 'p':
            period_ = positiveInteger("value of test period:"
                                      " -p<value> must be a positive integer");
            break;

        case 'P':
            preload_ = nonNegativeInteger("number of preload packets:"
                                          " -P<value> must not be "
                                          "a negative integer");
            break;

        case 'r':
            rate_ = positiveInteger("value of rate:"
                                    " -r<value> must be a positive integer");
            break;

        case 'R':
            initClientsNum();
            break;

        case 's':
            seed_ = static_cast<unsigned int>
                (nonNegativeInteger("value of seed:"
                                    " -s <seed> must be non-negative integer"));
            seeded_ = seed_ > 0 ? true : false;
            break;

        case 'S':
            sid_offset_ = positiveInteger("value of server id offset:"
                                          " -S<value> must be a"
                                          " positive integer");
            break;

        case 't':
            report_delay_ = positiveInteger("value of report delay:"
                                            " -t<value> must be a"
                                            " positive integer");
            break;

        case 'T':
            if (template_file_.size() < 2) {
                sarg = nonEmptyString("template file name not specified,"
                                      " expected -T<filename>");
                template_file_.push_back(sarg);
            } else {
                isc_throw(isc::InvalidParameter,
                          "template files are already specified,"
                          " unexpected 3rd -T<filename> occurrence");
            }
            break;

        case 'v':
            version();
            return (true);

        case 'w':
            wrapped_ = nonEmptyString("command for wrapped mode:"
                                      " -w<command> must be specified");
            break;

        case 'x':
            diags_ = nonEmptyString("value of diagnostics selectors:"
                                    " -x<value> must be specified");
            break;

        case 'X':
            if (xid_offset_.size() < 2) {
                offset_arg = positiveInteger("value of transaction id:"
                                             " -X<value> must be a"
                                             " positive integer");
            } else {
                isc_throw(isc::InvalidParameter,
                          "transaction ids already specified,"
                          " unexpected 3rd -X<value> occurrence");
            }
            xid_offset_.push_back(offset_arg);
            break;

        case 'Y':
            wait_for_elapsed_time_ = nonNegativeInteger("value of time:"
                                     " -Y<value> must be a non negative integer");
            break;

        case 'y':
            increased_elapsed_time_ = positiveInteger("value of time:"
                                      " -y<value> must be a positive integer");
            break;

        case LONG_OPT_SCENARIO: {
            std::string optarg_text(optarg ? optarg : "");
            if (optarg_text == "basic") {
                scenario_ = Scenario::BASIC;
            } else if (optarg_text == "avalanche") {
                scenario_ = Scenario::AVALANCHE;
            } else {
                isc_throw(InvalidParameter, "scenario value '" << optarg_text << "' is wrong - should be 'basic' or 'avalanche'");
            }
            break;
        }

        case LONG_OPT_RELAY_OPTION: {
            // for now this is only available for v6
            // and must be used together with -A option.
            check((ipversion_ != 6),
                  "-6 must be explicitly specified before --or is used.");
            check(v6_relay_encapsulation_level_ <= 0,
                  "-A must be explicitly specified before --or is used.");

            // custom option (expected format: encapsulation-level:code,hexstring)
            std::string opt_text(optarg ? optarg : "");
            size_t colon_loc = opt_text.find(':');
            size_t comma_loc = opt_text.find(',');

            // if encapsulation level is skipped by user, let's assume it is 1
            uint8_t option_encapsulation_level = 1;
            if (colon_loc == std::string::npos) {
                // if colon was not found, default encapsulation level will be used
                // and let's reset colon_loc to -1 so option code could be parsed later
                colon_loc = -1;
            } else {
                // Try to parse the encapsulation level
                try {
                    option_encapsulation_level =
                        boost::lexical_cast<int>(opt_text.substr(0, colon_loc));
                    check(option_encapsulation_level != 1, "Relayed option encapsulation level "
                                                           "supports only value 1 at the moment.");
                } catch (const boost::bad_lexical_cast&) {
                    isc_throw(InvalidParameter,
                              "Invalid relayed option encapsulation level specified for "
                              "--or option, expected format: --or <integer>:<integer>,<hexstring>");
                }
            }

            check(comma_loc == std::string::npos,
                  "--or option must provide encapsulation level, a colon, option code, a comma and "
                  "hexstring for the option content, e.g. --or 1:38,31323334 for sending option"
                  " 38 (subscriber-id) with the value 1234 at first level of encapsulation");
            int code = 0;

            // Try to parse the option code
            try {
                code = boost::lexical_cast<int>(
                    opt_text.substr(colon_loc + 1, comma_loc - colon_loc - 1));
                check(code <= 0, "Option code can't be negative or zero");
            } catch (const boost::bad_lexical_cast&) {
                isc_throw(InvalidParameter,
                          "Invalid option code specified for "
                          "--or option, expected format: --or <integer>:<integer>,<hexstring>");
            }

            // Now try to interpret the hexstring
            opt_text = opt_text.substr(comma_loc + 1);
            std::vector<uint8_t> bin;
            try {
                isc::util::encode::decodeHex(opt_text, bin);
            } catch (const BadValue& e) {
                isc_throw(InvalidParameter, "Error during decoding option --or:" << e.what());
            }

            // Create and remember the option.
            OptionPtr option(new Option(Option::V6, code, bin));
            auto relay_opts = relay_opts_.find(option_encapsulation_level);
            relay_opts->second.insert(make_pair(code, option));
            break;
        }
        default:
            isc_throw(isc::InvalidParameter, "wrong command line option");
        }
    }

    // If the IP version was not specified in the
    // command line, assume IPv4.
    if (ipversion_ == 0) {
        ipversion_ = 4;
    }

    // If template packet files specified for both DISCOVER/SOLICIT
    // and REQUEST/REPLY exchanges make sure we have transaction id
    // and random duid offsets for both exchanges. We will duplicate
    // value specified as -X<value> and -R<value> for second
    // exchange if user did not specified otherwise.
    if (template_file_.size() > 1) {
        if (xid_offset_.size() == 1) {
            xid_offset_.push_back(xid_offset_[0]);
        }
        if (rnd_offset_.size() == 1) {
            rnd_offset_.push_back(rnd_offset_[0]);
        }
    }

    // Get server argument
    // NoteFF02::1:2 and FF02::1:3 are defined in RFC 8415 as
    // All_DHCP_Relay_Agents_and_Servers and All_DHCP_Servers
    // addresses
    check(optind < argc -1, "extra arguments?");
    if (optind == argc - 1) {
        server_name_ = argv[optind];
        stream << " " << server_name_;
        // Decode special cases
        if ((ipversion_ == 4) && (server_name_.compare("all") == 0)) {
            broadcast_ = true;
            // Use broadcast address as server name.
            server_name_ = DHCP_IPV4_BROADCAST_ADDRESS;
        } else if ((ipversion_ == 6) && (server_name_.compare("all") == 0)) {
            server_name_ = ALL_DHCP_RELAY_AGENTS_AND_SERVERS;
        } else if ((ipversion_ == 6) &&
                   (server_name_.compare("servers") == 0)) {
            server_name_ = ALL_DHCP_SERVERS;
        }
    }
    if (!getCleanReport()) {
        if (print_cmd_line) {
            std::cout << "Running: " << stream.str() << std::endl;
        }

        if (scenario_ == Scenario::BASIC) {
            std::cout << "Scenario: basic." << std::endl;
        } else if (scenario_ == Scenario::AVALANCHE) {
            std::cout << "Scenario: avalanche." << std::endl;
        }

        if (!isSingleThreaded()) {
            std::cout << "Multi-thread mode enabled." << std::endl;
        }
    }

    // Handle the local '-l' address/interface
    if (!localname_.empty()) {
        if (server_name_.empty()) {
            if (is_interface_ && (ipversion_ == 4)) {
                broadcast_ = true;
                server_name_ = DHCP_IPV4_BROADCAST_ADDRESS;
            } else if (is_interface_ && (ipversion_ == 6)) {
                server_name_ = ALL_DHCP_RELAY_AGENTS_AND_SERVERS;
            }
        }
    }
    if (server_name_.empty()) {
        isc_throw(InvalidParameter,
                  "without an interface, server is required");
    }

    // If DUID is not specified from command line we need to
    // generate one.
    if (duid_template_.empty()) {
        generateDuidTemplate();
    }
    return (false);
}

void
CommandOptions::initClientsNum() {
    const std::string errmsg =
        "value of -R <value> must be non-negative integer";

    try {
        // Declare clients_num as a 64-bit signed value to
        // be able to detect negative values provided
        // by user. We would not detect negative values
        // if we casted directly to unsigned value.
        long long clients_num = boost::lexical_cast<long long>(optarg ? optarg : "");
        check(clients_num < 0, errmsg);
        clients_num_ = boost::lexical_cast<uint32_t>(optarg ? optarg : "");
    } catch (const boost::bad_lexical_cast&) {
        isc_throw(isc::InvalidParameter, errmsg);
    }
}

void
CommandOptions::initIsInterface() {
    is_interface_ = false;
    if (!localname_.empty()) {
        dhcp::IfaceMgr& iface_mgr = dhcp::IfaceMgr::instance();
        if (iface_mgr.getIface(localname_) != NULL)  {
            is_interface_ = true;
        }
    }
}

void
CommandOptions::decodeBase(const std::string& base) {
    std::string b(base);
    boost::algorithm::to_lower(b);

    // Currently we only support mac and duid
    if ((b.substr(0, 4) == "mac=") || (b.substr(0, 6) == "ether=")) {
        decodeMacBase(b);
    } else if (b.substr(0, 5) == "duid=") {
        decodeDuid(b);
    } else {
        isc_throw(isc::InvalidParameter,
                  "base value not provided as -b<value>,"
                  " expected -b mac=<mac> or -b duid=<duid>");
    }
}

void
CommandOptions::decodeMacBase(const std::string& base) {
    // Strip string from mac=
    size_t found = base.find('=');
    static const char* errmsg = "expected -b<base> format for"
        " mac address is -b mac=00::0C::01::02::03::04 or"
        " -b mac=00:0C:01:02:03:04";
    check(found == std::string::npos, errmsg);

    // Decode mac address to vector of uint8_t
    std::istringstream s1(base.substr(found + 1));
    std::string token;
    mac_template_.clear();
    // Get pieces of MAC address separated with : (or even ::)
    while (std::getline(s1, token, ':')) {
        // Convert token to byte value using std::istringstream
        if (token.length() > 0) {
            unsigned int ui = 0;
            try {
                // Do actual conversion
                ui = convertHexString(token);
            } catch (const isc::InvalidParameter&) {
                isc_throw(isc::InvalidParameter,
                          "invalid characters in MAC provided");

            }
            // If conversion succeeded store byte value
            mac_template_.push_back(ui);
        }
    }
    // MAC address must consist of 6 octets, otherwise it is invalid
    check(mac_template_.size() != 6, errmsg);
}

void
CommandOptions::decodeDuid(const std::string& base) {
    // Strip argument from duid=
    std::vector<uint8_t> duid_template;
    size_t found = base.find('=');
    check(found == std::string::npos, "expected -b<base>"
          " format for duid is -b duid=<duid>");
    std::string b = base.substr(found + 1);

    // DUID must have even number of digits and must not be longer than 64 bytes
    check(b.length() & 1, "odd number of hexadecimal digits in duid");
    check(b.length() > 128, "duid too large");
    check(b.length() == 0, "no duid specified");

    // Turn pairs of hexadecimal digits into vector of octets
    for (size_t i = 0; i < b.length(); i += 2) {
        unsigned int ui = 0;
        try {
            // Do actual conversion
            ui = convertHexString(b.substr(i, 2));
        } catch (const isc::InvalidParameter&) {
            isc_throw(isc::InvalidParameter,
                      "invalid characters in DUID provided,"
                      " expected hex digits");
        }
        duid_template.push_back(static_cast<uint8_t>(ui));
    }
    // @todo Get rid of this limitation when we manage add support
    // for DUIDs other than LLT. Shorter DUIDs may be useful for
    // server testing purposes.
    check(duid_template.size() < 6, "DUID must be at least 6 octets long");
    // Assign the new duid only if successfully generated.
    std::swap(duid_template, duid_template_);
}

void
CommandOptions::generateDuidTemplate() {
    using namespace boost::posix_time;
    // Duid template will be most likely generated only once but
    // it is ok if it is called more then once so we simply
    //  regenerate it and discard previous value.
    duid_template_.clear();
    const uint8_t duid_template_len = 14;
    duid_template_.resize(duid_template_len);
    // The first four octets consist of DUID LLT and hardware type.
    duid_template_[0] = static_cast<uint8_t>(static_cast<uint16_t>(isc::dhcp::DUID::DUID_LLT) >> 8);
    duid_template_[1] = static_cast<uint8_t>(static_cast<uint16_t>(isc::dhcp::DUID::DUID_LLT) & 0xff);
    duid_template_[2] = HWTYPE_ETHERNET >> 8;
    duid_template_[3] = HWTYPE_ETHERNET & 0xff;

    // As described in RFC 8415: 'the time value is the time
    // that the DUID is generated represented in seconds
    // since midnight (UTC), January 1, 2000, modulo 2^32.'
    ptime now = microsec_clock::universal_time();
    ptime duid_epoch(from_iso_string("20000101T000000"));
    time_period period(duid_epoch, now);
    uint32_t duration_sec = htonl(period.length().total_seconds());
    memcpy(&duid_template_[4], &duration_sec, 4);

    // Set link layer address (6 octets). This value may be
    // randomized before sending a packet to simulate different
    // clients.
    memcpy(&duid_template_[8], &mac_template_[0], 6);
}

const isc::dhcp::OptionCollection&
CommandOptions::getRelayOpts(uint8_t encapsulation_level) const {
    if (encapsulation_level > RELAY_OPTIONS_MAX_ENCAPSULATION) {
        isc_throw(isc::OutOfRange,
                  "Trying to access relay options at encapsulation level that doesn't exist");
    }

    return relay_opts_.find(encapsulation_level)->second;
}

uint8_t
CommandOptions::convertHexString(const std::string& text) const {
    unsigned int ui = 0;
    // First, check if we are dealing with hexadecimal digits only
    for (size_t i = 0; i < text.length(); ++i) {
        if (!std::isxdigit(text[i])) {
            isc_throw(isc::InvalidParameter,
                      "The following digit: " << text[i] << " in "
                      << text << "is not hexadecimal");
        }
    }
    // If we are here, we have valid string to convert to octet
    std::istringstream text_stream(text);
    text_stream >> std::hex >> ui >> std::dec;
    // Check if for some reason we have overflow - this should never happen!
    if (ui > 0xFF) {
        isc_throw(isc::InvalidParameter, "Can't convert more than"
                  " two hex digits to byte");
    }
    return ui;
}

bool CommandOptions::validateIP(const std::string& line) {
    try {
        isc::asiolink::IOAddress ip_address(line);
        if ((getIpVersion() == 4 && !ip_address.isV4()) ||
            (getIpVersion() == 6 && !ip_address.isV6())) {
            return (true);
        }
    } catch (const isc::asiolink::IOError& e) {
        return (true);
    }
    relay_addr_list_.push_back(line);
    multi_subnet_ = true;
    return (false);
}

void CommandOptions::loadRelayAddr() {
    std::string line;
    std::ifstream infile(relay_addr_list_file_.c_str());
    size_t cnt = 0;
    while (std::getline(infile, line)) {
        cnt++;
        stringstream tmp;
        tmp << "invalid address or wrong address version in line: " << cnt;
        check(validateIP(line), tmp.str());
    }
    check(cnt == 0, "file with addresses is empty!");
}

void CommandOptions::loadMacs() {
    std::string line;
    std::ifstream infile(mac_list_file_.c_str());
    size_t cnt = 0;
    while (std::getline(infile, line)) {
        cnt++;
        stringstream tmp;
        tmp << "invalid mac in input line " << cnt;
        // Let's print more meaningful error that contains line with error.
        check(decodeMacString(line), tmp.str());
    }
}

bool CommandOptions::decodeMacString(const std::string& line) {
  // decode mac string into a vector of uint8_t returns true in case of error.
  std::istringstream s(line);
  std::string token;
  std::vector<uint8_t> mac;
  while(std::getline(s, token, ':')) {
    // Convert token to byte value using std::istringstream
    if (token.length() > 0) {
      unsigned int ui = 0;
      try {
        // Do actual conversion
        ui = convertHexString(token);
      } catch (const isc::InvalidParameter&) {
        return (true);
      }
      // If conversion succeeded store byte value
      mac.push_back(ui);
    }
  }
  mac_list_.push_back(mac);
  return (false);
}

void
CommandOptions::validate() {
    check((getIpVersion() != 4) && (isBroadcast() != 0),
          "-B is not compatible with IPv6 (-6)");
    check((getIpVersion() != 6) && (isRapidCommit() != 0),
          "-6 (IPv6) must be set to use -c");
    check(getIpVersion() == 4 && isUseRelayedV6(),
          "Can't use -4 with -A, it's a V6 only option.");
    check((getExchangeMode() == DO_SA) && (getNumRequests().size() > 1),
          "second -n<num-request> is not compatible with -i");
    check((getIpVersion() == 4) && !getLeaseType().is(LeaseType::ADDRESS),
          "-6 option must be used if lease type other than '-e address-only'"
          " is specified");
    check(!getTemplateFiles().empty() &&
          !getLeaseType().is(LeaseType::ADDRESS),
          "template files may be only used with '-e address-only'");
    check((getExchangeMode() == DO_SA) && (getDropTime()[1] != 1.),
          "second -d<drop-time> is not compatible with -i");
    check((getExchangeMode() == DO_SA) &&
          ((getMaxDrop().size() > 1) || (getMaxDropPercentage().size() > 1)),
          "second -D<max-drop> is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (isUseFirst()),
          "-1 is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getTemplateFiles().size() > 1),
          "second -T<template-file> is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getTransactionIdOffset().size() > 1),
          "second -X<xid-offset> is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getRandomOffset().size() > 1),
          "second -O<random-offset is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getElapsedTimeOffset() >= 0),
          "-E<time-offset> is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getServerIdOffset() >= 0),
          "-S<srvid-offset> is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getRequestedIpOffset() >= 0),
          "-I<ip-offset> is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getRenewRate() != 0),
          "-f<renew-rate> is not compatible with -i");
    check((getExchangeMode() == DO_SA) && (getReleaseRate() != 0),
          "-F<release-rate> is not compatible with -i");
    check((getExchangeMode() != DO_SA) && (isRapidCommit() != 0),
          "-i must be set to use -c");
    check((getRate() != 0) && (getRenewRate() + getReleaseRate() > getRate()),
          "The sum of Renew rate (-f<renew-rate>) and Release rate"
          " (-F<release-rate>) must not be greater than the exchange"
          " rate specified as -r<rate>");
    check((getRate() == 0) && (getRenewRate() != 0),
          "Renew rate specified as -f<renew-rate> must not be specified"
          " when -r<rate> parameter is not specified");
    check((getRate() == 0) && (getReleaseRate() != 0),
          "Release rate specified as -F<release-rate> must not be specified"
          " when -r<rate> parameter is not specified");
    check((getTemplateFiles().size() < getTransactionIdOffset().size()),
          "-T<template-file> must be set to use -X<xid-offset>");
    check((getTemplateFiles().size() < getRandomOffset().size()),
          "-T<template-file> must be set to use -O<random-offset>");
    check((getTemplateFiles().size() < 2) && (getElapsedTimeOffset() >= 0),
          "second/request -T<template-file> must be set to use -E<time-offset>");
    check((getTemplateFiles().size() < 2) && (getServerIdOffset() >= 0),
          "second/request -T<template-file> must be set to "
          "use -S<srvid-offset>");
    check((getTemplateFiles().size() < 2) && (getRequestedIpOffset() >= 0),
          "second/request -T<template-file> must be set to "
          "use -I<ip-offset>");
    check((!getMacListFile().empty() && base_.size() > 0),
          "Can't use -b with -M option");
    check((getWaitForElapsedTime() == -1 && getIncreaseElapsedTime() != -1),
	  "Option -y can't be used without -Y");
    check((getWaitForElapsedTime() != -1 && getIncreaseElapsedTime() == -1),
	  "Option -Y can't be used without -y");
    auto nthreads = std::thread::hardware_concurrency();
    if (nthreads == 1 && isSingleThreaded() == false) {
        std::cout << "WARNING: Currently system can run only 1 thread in parallel." << std::endl
                  << "WARNING: Better results are achieved when run in single-threaded mode." << std::endl
                  << "WARNING: To switch use -g single option." << std::endl;
    } else if (nthreads > 1 && isSingleThreaded()) {
        std::cout << "WARNING: Currently system can run more than 1 thread in parallel." << std::endl
                  << "WARNING: Better results are achieved when run in multi-threaded mode." << std::endl
                  << "WARNING: To switch use -g multi option." << std::endl;
    }

    if (scenario_ == Scenario::AVALANCHE) {
        check(getClientsNum() <= 0,
              "in case of avalanche scenario number\nof clients must be specified"
              " using -R option explicitly");

        // in case of AVALANCHE drops ie. long responses should not be observed by perfdhcp
        double dt[2] = { 1000.0, 1000.0 };
        drop_time_.assign(dt, dt + 2);
        if (drop_time_set_) {
            std::cout << "INFO: in avalanche scenario drop time is ignored" << std::endl;
        }
    }
}

void
CommandOptions::check(bool condition, const std::string& errmsg) const {
    // The same could have been done with macro or just if statement but
    // we prefer functions to macros here
    std::ostringstream stream;
    stream << errmsg << "\n";
    if (condition) {
        isc_throw(isc::InvalidParameter, errmsg);
    }
}

int
CommandOptions::positiveInteger(const std::string& errmsg) const {
    try {
        int value = boost::lexical_cast<int>(optarg ? optarg : "");
        check(value <= 0, errmsg);
        return (value);
    } catch (const boost::bad_lexical_cast&) {
        isc_throw(InvalidParameter, errmsg);
    }
}

int
CommandOptions::nonNegativeInteger(const std::string& errmsg) const {
    try {
        int value = boost::lexical_cast<int>(optarg ? optarg : "");
        check(value < 0, errmsg);
        return (value);
    } catch (const boost::bad_lexical_cast&) {
        isc_throw(InvalidParameter, errmsg);
    }
}

std::string
CommandOptions::nonEmptyString(const std::string& errmsg) const {
    std::string sarg(optarg ? optarg : "");
    if (sarg.length() == 0) {
        isc_throw(isc::InvalidParameter, errmsg);
    }
    return sarg;
}

void
CommandOptions::initLeaseType() {
    std::string lease_type_arg(optarg ? optarg : "");
    lease_type_.fromCommandLine(lease_type_arg);
}

void
CommandOptions::printCommandLine() const {
    std::cout << "IPv" << static_cast<int>(ipversion_) << std::endl;
    if (exchange_mode_ == DO_SA) {
        if (ipversion_ == 4) {
            std::cout << "DISCOVER-OFFER only" << std::endl;
        } else {
            std::cout << "SOLICIT-ADVERTISE only" << std::endl;
        }
    }
    std::cout << "lease-type=" << getLeaseType().toText() << std::endl;
    if (rate_ != 0) {
        std::cout << "rate[1/s]=" << rate_ <<  std::endl;
    }
    if (getRenewRate() != 0) {
        std::cout << "renew-rate[1/s]=" << getRenewRate() << std::endl;
    }
    if (getReleaseRate() != 0) {
        std::cout << "release-rate[1/s]=" << getReleaseRate() << std::endl;
    }
    if (report_delay_ != 0) {
        std::cout << "report[s]=" << report_delay_ << std::endl;
    }
    if (clients_num_ != 0) {
        std::cout << "clients=" << clients_num_ << std::endl;
    }
    for (size_t i = 0; i < base_.size(); ++i) {
        std::cout << "base[" << i << "]=" << base_[i] <<  std::endl;
    }
    for (size_t i = 0; i < num_request_.size(); ++i) {
        std::cout << "num-request[" << i << "]=" << num_request_[i] << std::endl;
    }
    if (period_ != 0) {
        std::cout << "test-period=" << period_ << std::endl;
    }
    for (size_t i = 0; i < drop_time_.size(); ++i) {
        std::cout << "drop-time[" << i << "]=" << drop_time_[i] << std::endl;
    }
    for (size_t i = 0; i < max_drop_.size(); ++i) {
        std::cout << "max-drop{" << i << "]=" << max_drop_[i] << std::endl;
    }
    for (size_t i = 0; i < max_pdrop_.size(); ++i) {
        std::cout << "max-pdrop{" << i << "]=" << max_pdrop_[i] << std::endl;
    }
    if (preload_ != 0) {
        std::cout << "preload=" << preload_ <<  std::endl;
    }
    if (getLocalPort() != 0) {
        std::cout << "local-port=" << local_port_ <<  std::endl;
    }
    if (getRemotePort() != 0) {
        std::cout << "remote-port=" << remote_port_ <<  std::endl;
    }
    if (seeded_) {
        std::cout << "seed=" << seed_ << std::endl;
    }
    if (broadcast_) {
        std::cout << "broadcast" << std::endl;
    }
    if (rapid_commit_) {
        std::cout << "rapid-commit" << std::endl;
    }
    if (use_first_) {
        std::cout << "use-first" << std::endl;
    }
    if (!mac_list_file_.empty()) {
        std::cout << "mac-list-file=" << mac_list_file_ << std::endl;
    }
    for (size_t i = 0; i < template_file_.size(); ++i) {
        std::cout << "template-file[" << i << "]=" << template_file_[i] << std::endl;
    }
    for (size_t i = 0; i < xid_offset_.size(); ++i) {
        std::cout << "xid-offset[" << i << "]=" << xid_offset_[i] << std::endl;
    }
    if (elp_offset_ != 0) {
        std::cout << "elp-offset=" << elp_offset_ << std::endl;
    }
    for (size_t i = 0; i < rnd_offset_.size(); ++i) {
        std::cout << "rnd-offset[" << i << "]=" << rnd_offset_[i] << std::endl;
    }
    if (sid_offset_ != 0) {
        std::cout << "sid-offset=" << sid_offset_ << std::endl;
    }
    if (rip_offset_ != 0) {
        std::cout << "rip-offset=" << rip_offset_ << std::endl;
    }
    if (!diags_.empty()) {
        std::cout << "diagnostic-selectors=" << diags_ <<  std::endl;
    }
    if (!wrapped_.empty()) {
        std::cout << "wrapped=" << wrapped_ << std::endl;
    }
    if (!localname_.empty()) {
        if (is_interface_) {
            std::cout << "interface=" << localname_ << std::endl;
        } else {
            std::cout << "local-addr=" << localname_ << std::endl;
        }
    }
    if (!server_name_.empty()) {
        std::cout << "server=" << server_name_ << std::endl;
    }
    if (single_thread_mode_) {
        std::cout << "single-thread-mode" << std::endl;
    } else {
        std::cout << "multi-thread-mode" << std::endl;
    }
}

void
CommandOptions::usage() {
    std::cout <<
R"(perfdhcp [-1] [-4 | -6] [-A encapsulation-level] [-b base] [-B] [-c]
         [-C separator] [-d drop-time] [-D max-drop] [-e lease-type]
         [-E time-offset] [-f renew-rate] [-F release-rate] [-g thread-mode]
         [-h] [-i] [-I ip-offset] [-J remote-address-list-file]
         [-l local-address|interface] [-L local-port] [-M mac-list-file]
         [-n num-request] [-N remote-port] [-O random-offset]
         [-o code,hexstring] [--or encapsulation-level:code,hexstring]
         [-p test-period] [-P preload] [-r rate]
         [-R num-clients] [-s seed] [-S srvid-offset] [--scenario name]
         [-t report] [-T template-file] [-u] [-v] [-W exit-wait-time]
         [-w script_name] [-x diagnostic-selector] [-X xid-offset] [server]

The [server] argument is the name/address of the DHCP server to
contact.  For DHCPv4 operation, exchanges are initiated by
transmitting a DHCP DISCOVER to this address.

For DHCPv6 operation, exchanges are initiated by transmitting a DHCP
SOLICIT to this address.  In the DHCPv6 case, the special name 'all'
can be used to refer to All_DHCP_Relay_Agents_and_Servers (the
multicast address FF02::1:2), or the special name 'servers' to refer
to All_DHCP_Servers (the multicast address FF05::1:3).  The [server]
argument is optional only in the case that -l is used to specify an
interface, in which case [server] defaults to 'all'.

The default is to perform a single 4-way exchange, effectively pinging
the server.
The -r option is used to set up a performance test, without
it exchanges are initiated as fast as possible.
The other scenario is an avalanche which is selected by
--scenario avalanche. It first sends as many Discovery or Solicit
messages as request in -R option then back off mechanism is used for
each simulated client until all requests are answered. At the end
time of whole scenario is reported.

Options:
-1: Take the server-ID option from the first received message.
-4: DHCPv4 operation (default). This is incompatible with the -6 option.
-6: DHCPv6 operation. This is incompatible with the -4 option.
-b<base>: The base mac, duid, IP, etc, used to simulate different
    clients.  This can be specified multiple times, each instance is
    in the <type>=<value> form, for instance:
    (and default) mac=00:0c:01:02:03:04.
-d<drop-time>: Specify the time after which a request is treated as
    having been lost.  The value is given in seconds and may contain a
    fractional component.  The default is 1 second.
-e<lease-type>: A type of lease being requested from the server. It
    may be one of the following: address-only, prefix-only or
    address-and-prefix. The address-only indicates that the regular
    address (v4 or v6) will be requested. The prefix-only indicates
    that the IPv6 prefix will be requested. The address-and-prefix
    indicates that both IPv6 address and prefix will be requested.
    The '-e prefix-only' and -'e address-and-prefix' must not be
    used with -4.
-E<time-offset>: Offset of the (DHCPv4) secs field / (DHCPv6)
    elapsed-time option in the (second/request) template.
    The value 0 disables it.
-F<release-rate>: Rate at which Release requests are sent to
    a server. This value is only valid when used in conjunction with
    the exchange rate (given by -r<rate>).  Furthermore the sum of
    this value and the renew-rate (given by -f<rate>) must be equal
    to or less than the exchange rate.
-f<renew-rate>: Rate at which DHCPv4 or DHCPv6 renew requests are sent
    to a server. This value is only valid when used in conjunction
    with the exchange rate (given by -r<rate>).  Furthermore the sum of
    this value and the release-rate (given by -F<rate>) must be equal
    to or less than the exchange rate.
-g<thread-mode>: 'single' or 'multi'. In multi-thread mode packets
    are received in separate thread. This allows better utilisation of CPUs.
    If more than 1 CPU is present then multi-thread mode is the default,
    otherwise single-thread is the default.
-h: Print this help.
-i: Do only the initial part of an exchange: DO or SA, depending on
    whether -6 is given.
-I<ip-offset>: Offset of the (DHCPv4) IP address in the requested-IP
    option / (DHCPv6) IA_NA option in the (second/request) template.
-J<remote-address-list-file>: Text file that include multiple addresses.
    If provided perfdhcp will choose randomly one of addresses for each
    exchange.
-l<local-addr|interface>: For DHCPv4 operation, specify the local
    hostname/address to use when communicating with the server.  By
    default, the interface address through which traffic would
    normally be routed to the server is used.
    For DHCPv6 operation, specify the name of the network interface
    via which exchanges are initiated.
-L<local-port>: Specify the local port to use
    (the value 0 means to use the default).
-M<mac-list-file>: A text file containing a list of MAC addresses,
   one per line. If provided, a MAC address will be chosen randomly
   from this list for every new exchange. In the DHCPv6 case, MAC
   addresses are used to generate DUID-LLs. This parameter must not be
   used in conjunction with the -b parameter.
-N<remote-port>: Specify the remote port to use
    (the value 0 means to use the default).
-o<code,hexstring>: Send custom option with the specified code and the
    specified buffer in hexstring format.
-O<random-offset>: Offset of the last octet to randomize in the template.
-P<preload>: Initiate first <preload> exchanges back to back at startup.
-r<rate>: Initiate <rate> DORA/SARR (or if -i is given, DO/SA)
    exchanges per second.  A periodic report is generated showing the
    number of exchanges which were not completed, as well as the
    average response latency.  The program continues until
    interrupted, at which point a final report is generated.
-R<range>: Specify how many different clients are used. With 1
    (the default), all requests seem to come from the same client.
-s<seed>: Specify the seed for randomization, making it repeatable.
--scenario <name>: where name is 'basic' (default) or 'avalanche'.
-S<srvid-offset>: Offset of the server-ID option in the
    (second/request) template.
-T<template-file>: The name of a file containing the template to use
    as a stream of hexadecimal digits.
-u: Enable checking address uniqueness. Lease valid lifetime should not be
    shorter than test duration and clients should not request address more than
    once without releasing it first.
-v: Report the version number of this program.
-W<time>: Specifies exit-wait-time parameter, that makes perfdhcp wait
    for <time> us after an exit condition has been met to receive all
    packets without sending any new packets. Expressed in microseconds.
-w<wrapped>: Command to call with start/stop at the beginning/end of
    the program.
-x<diagnostic-selector>: Include extended diagnostics in the output.
    <diagnostic-selector> is a string of single-keywords specifying
    the operations for which verbose output is desired.  The selector
    key letters are:
   * 'a': print the decoded command line arguments
   * 'e': print the exit reason
   * 'i': print rate processing details
   * 'l': print received leases
   * 's': print first server-id
   * 't': when finished, print timers of all successful exchanges
   * 'T': when finished, print templates
-X<xid-offset>: Transaction ID (aka. xid) offset in the template.
-Y<time>: time in seconds after which perfdhcp will start sending
    messages with increased elapsed time option.
-y<time>: period of time in seconds in which perfdhcp will be sending
    messages with increased elapsed time option.
DHCPv4 only options:
-B: Force broadcast handling.

DHCPv6 only options:
-c: Add a rapid commit option (exchanges will be SA).
-A<encapsulation-level>: Specifies that relayed traffic must be
    generated. The argument specifies the level of encapsulation, i.e.
    how many relay agents are simulated. Currently the only supported
    <encapsulation-level> value is 1, which means that the generated
    traffic is an equivalent of the traffic passing through a single
    relay agent.
--or encapsulation-level:<code,hexstring>: Send given option included
    to simulated DHCPv6 relayed traffic at given level of encapsulation
    with the specified code and the specified buffer in hexstring format.
    Currently the only supported encapsulation-level value is 1.
    Must be used together with -A.

The remaining options are typically used in conjunction with -r:

-D<max-drop>: Abort the test immediately if max-drop requests have
    been dropped.  max-drop must be a positive integer. If max-drop
    includes the suffix '%', it specifies a maximum percentage of
    requests that may be dropped before abort. In this case, testing
    of the threshold begins after 10 requests have been expected to
    be received.
-n<num-request>: Initiate <num-request> transactions.  No report is
    generated until all transactions have been initiated/waited-for,
    after which a report is generated and the program terminates.
-p<test-period>: Send requests for the given test period, which is
    specified in the same manner as -d.  This can be used as an
    alternative to -n, or both options can be given, in which case the
    testing is completed when either limit is reached.
-t<report>: Delay in seconds between two periodic reports.
-C<separator>: Output reduced, an argument is a separator for periodic
    (-t) reports generated in easy parsable mode. Data output won't be
    changed, remain identical as in -t option.

Errors:
- tooshort: received a too short message
- orphans: received a message which doesn't match an exchange
   (duplicate, late or not related)
- locallimit: reached to local system limits when sending a message.

Exit status:
The exit status is:
0 on complete success.
1 for a general error.
2 if an error is found in the command line arguments.
3 if there are no general failures in operation, but one or more
  exchanges are not successfully completed.
)";
}

void
CommandOptions::version() const {
    std::cout << "VERSION: " << VERSION << std::endl;
}


}  // namespace perfdhcp
}  // namespace isc