Adding upstream version 2.4.1.upstream/2.4.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1258 insertions, 0 deletions

diff --git a/src/bin/perfdhcp/stats_mgr.h b/src/bin/perfdhcp/stats_mgr.h
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+++ b/src/bin/perfdhcp/stats_mgr.h
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+// Copyright (C) 2012-2021 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/.
+
+#ifndef STATS_MGR_H
+#define STATS_MGR_H
+
+#include <dhcp/pkt.h>
+#include <exceptions/exceptions.h>
+#include <perfdhcp/command_options.h>
+
+#include <boost/noncopyable.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/multi_index_container.hpp>
+#include <boost/multi_index/ordered_index.hpp>
+#include <boost/multi_index/sequenced_index.hpp>
+#include <boost/multi_index/global_fun.hpp>
+#include <boost/multi_index/mem_fun.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+
+#include <iostream>
+#include <map>
+#include <queue>
+
+
+namespace isc {
+namespace perfdhcp {
+
+/// DHCP packet exchange types.
+enum class ExchangeType {
+    DO,  ///< DHCPv4 DISCOVER-OFFER
+    RA,  ///< DHCPv4 REQUEST-ACK
+    RNA, ///< DHCPv4 REQUEST-ACK (renewal)
+    RLA, ///< DHCPv4 RELEASE
+    SA,  ///< DHCPv6 SOLICIT-ADVERTISE
+    RR,  ///< DHCPv6 REQUEST-REPLY
+    RN,  ///< DHCPv6 RENEW-REPLY
+    RL   ///< DHCPv6 RELEASE-REPLY
+};
+
+/// \brief Get the DHCP version that fits the exchange type.
+///
+/// \param exchange_type exchange type that will determine the version
+/// \throw isc::BadValue exchange type is unrecognized
+/// \return DHCP version: 4 or 6
+int dhcpVersion(ExchangeType const exchange_type);
+
+/// \brief Return name of the exchange.
+///
+/// Function returns name of the specified exchange type.
+/// This function is mainly for logging purposes.
+///
+/// \param os output stream to use.
+/// \param xchg_type exchange type.
+/// \return string representing name of the exchange.
+std::ostream& operator<<(std::ostream& os, ExchangeType xchg_type);
+
+/// \brief Custom Counter
+///
+/// This class represents custom statistics counters. Client class
+/// may create unlimited number of counters. Such counters are
+/// being stored in map in Statistics Manager and access using
+/// unique string key.
+class CustomCounter {
+public:
+    /// \brief Constructor.
+    ///
+    /// This constructor sets counter name. This name is used in
+    /// log file to report value of each counter.
+    ///
+    /// \param name name of the counter used in log file.
+    CustomCounter(const std::string& name) :
+        counter_(0),
+        name_(name) {
+    }
+
+    /// \brief Increment operator.
+    const CustomCounter& operator++() {
+        ++counter_;
+        return (*this);
+    }
+
+    /// \brief Increment operator.
+    const CustomCounter& operator++(int) {
+        CustomCounter& this_counter(*this);
+        operator++();
+        return (this_counter);
+    }
+
+    const CustomCounter& operator+=(int val) {
+        counter_ += val;
+        return (*this);
+    }
+
+    /// \brief Return counter value.
+    ///
+    /// Method returns counter value.
+    ///
+    /// \return counter value.
+    uint64_t getValue() const {
+        return (counter_);
+    }
+
+    /// \brief Return counter name.
+    ///
+    /// Method returns counter name.
+    ///
+    /// \return counter name.
+    const std::string& getName() const {
+        return (name_);
+    }
+
+private:
+    /// \brief Default constructor.
+    ///
+    /// Default constructor is private because we don't want client
+    /// class to call it because we want client class to specify
+    /// counter's name.
+    CustomCounter() : counter_(0) {
+    }
+
+    uint64_t counter_;  ///< Counter's value.
+    std::string name_;  ///< Counter's name.
+};
+
+typedef typename boost::shared_ptr<CustomCounter> CustomCounterPtr;
+
+/// Map containing custom counters.
+typedef typename std::map<std::string, CustomCounterPtr> CustomCountersMap;
+
+/// Iterator for \ref CustomCountersMap.
+typedef typename CustomCountersMap::const_iterator CustomCountersMapIterator;
+
+
+/// \brief Exchange Statistics.
+///
+/// This class collects statistics for exchanges. Parent class
+/// may define number of different packet exchanges like:
+/// DHCPv4 DISCOVER-OFFER, DHCPv6 SOLICIT-ADVERTISE etc. Performance
+/// statistics will be collected for each of those separately in
+/// corresponding instance of ExchangeStats.
+class ExchangeStats {
+public:
+
+    /// \brief Hash transaction id of the packet.
+    ///
+    /// Function hashes transaction id of the packet. Hashing is
+    /// non-unique. Many packets may have the same hash value and thus
+    /// they belong to the same packet buckets. Packet buckets are
+    /// used for unordered packets search with multi index container.
+    ///
+    /// \param packet packet which transaction id is to be hashed.
+    /// \throw isc::BadValue if packet is null.
+    /// \return transaction id hash.
+    static uint32_t hashTransid(const dhcp::PktPtr& packet) {
+        if (!packet) {
+            isc_throw(BadValue, "Packet is null");
+        }
+        return(packet->getTransid() & 1023);
+    }
+
+    /// \brief List of packets (sent or received).
+    ///
+    /// List of packets based on multi index container allows efficient
+    /// search of packets based on their sequence (order in which they
+    /// were inserted) as well as based on their hashed transaction id.
+    /// The first index (sequenced) provides the way to use container
+    /// as a regular list (including iterators, removal of elements from
+    /// the middle of the collection etc.). This index is meant to be used
+    /// more frequently than the latter one and it is based on the
+    /// assumption that responses from the DHCP server are received in
+    /// order. In this case, when next packet is received it can be
+    /// matched with next packet on the list of sent packets. This
+    /// prevents intensive searches on the list of sent packets every
+    /// time new packet arrives. In many cases however packets can be
+    /// dropped by the server or may be sent out of order and we still
+    ///  want to have ability to search packets using transaction id.
+    /// The second index can be used for this purpose. This index is
+    /// hashing transaction ids using custom function \ref hashTransid.
+    /// Note that other possibility would be to simply specify index
+    /// that uses transaction id directly (instead of hashing with
+    /// \ref hashTransid). In this case however we have chosen to use
+    /// hashing function because it shortens the index size to just
+    /// 1023 values maximum. Search operation on this index generally
+    /// returns the range of packets that have the same transaction id
+    /// hash assigned but most often these ranges will be short so further
+    /// search within a range to find a packet with particular transaction
+    /// id will not be intensive.
+    ///
+    /// Example 1: Add elements to the list
+    /// \code
+    /// PktList packets_collection();
+    /// boost::shared_ptr<Pkt4> pkt1(new Pkt4(...));
+    /// boost::shared_ptr<Pkt4> pkt2(new Pkt4(...));
+    /// // Add new packet to the container, it will be available through
+    /// // both indexes
+    /// static_cast<void>(packets_collection.push_back(pkt1));
+    /// // Here is another way to add packet to the container. The result
+    /// // is exactly the same as previously.
+    /// static_cast<void>(packets_collection.template get<0>().push_back(pkt2));
+    /// \endcode
+    ///
+    /// @note The multi index has no unique index so insertion should never
+    /// fail and there is no need to check the return of push_back().
+    ///
+    /// Example 2: Access elements through sequential index
+    /// \code
+    /// PktList packets_collection();
+    /// ...  # Add elements to the container
+    /// for (PktListIterator it = packets_collection.begin();
+    ///      it != packets_collection.end();
+    ///      ++it) {
+    ///          boost::shared_ptr<Pkt4> pkt = *it;
+    ///          # Do something with packet;
+    ///      }
+    /// \endcode
+    ///
+    /// Example 3: Access elements through ordered index by hash
+    /// \code
+    /// // Get the instance of the second search index.
+    /// PktListTransidHashIndex& idx = sent_packets_.template get<1>();
+    /// // Get the range (bucket) of packets sharing the same transaction
+    /// // id hash.
+    /// std::pair<PktListTransidHashIterator,PktListTransidHashIterator> p =
+    ///     idx.equal_range(hashTransid(rcvd_packet));
+    /// // Iterate through the returned bucket.
+    /// for (PktListTransidHashIterator it = p.first; it != p.second;
+    ///     ++it) {
+    ///    boost::shared_ptr pkt = *it;
+    ///    ... # Do something with the packet (e.g. check transaction id)
+    /// }
+    /// \endcode
+    typedef boost::multi_index_container<
+        // Container holds PktPtr objects.
+        dhcp::PktPtr,
+        // List container indexes.
+        boost::multi_index::indexed_by<
+            // Sequenced index provides the way to use this container
+            // in the same way as std::list.
+            boost::multi_index::sequenced<>,
+            // The other index keeps products of transaction id.
+            // Elements with the same hash value are grouped together
+            // into buckets and transactions are ordered from the
+            // oldest to latest within a bucket.
+            boost::multi_index::ordered_non_unique<
+                // Specify hash function to get the product of
+                // transaction id. This product is obtained by calling
+                // hashTransid() function.
+                boost::multi_index::global_fun<
+                    // Hashing function takes PktPtr as argument.
+                    const dhcp::PktPtr&,
+                    // ... and returns uint32 value.
+                    uint32_t,
+                    // ... and here is a reference to it.
+                    &ExchangeStats::hashTransid
+                    >
+                >
+            >
+        > PktList;
+
+    /// Packet list iterator for sequential access to elements.
+    typedef typename PktList::iterator PktListIterator;
+    /// Packet list index to search packets using transaction id hash.
+    typedef typename PktList::template nth_index<1>::type
+    PktListTransidHashIndex;
+    /// Packet list iterator to access packets using transaction id hash.
+    typedef typename PktListTransidHashIndex::const_iterator
+    PktListTransidHashIterator;
+    /// Packet list iterator queue for removal.
+    typedef typename std::queue<PktListTransidHashIterator>
+    PktListRemovalQueue;
+
+    /// \brief Constructor
+    ///
+    /// \param xchg_type exchange type
+    /// \param drop_time maximum time elapsed before packet is
+    /// assumed dropped. Negative value disables it.
+    /// \param archive_enabled if true packets archive mode is enabled.
+    /// In this mode all packets are stored throughout the test execution.
+    /// \param boot_time Holds the timestamp when perfdhcp has been started.
+    ExchangeStats(const ExchangeType xchg_type,
+                  const double drop_time,
+                  const bool archive_enabled,
+                  const boost::posix_time::ptime boot_time);
+
+    /// \brief Add new packet to list of sent packets.
+    ///
+    /// Method adds new packet to list of sent packets.
+    ///
+    /// \param packet packet object to be added.
+    /// \throw isc::BadValue if packet is null.
+    void appendSent(const dhcp::PktPtr& packet) {
+        if (!packet) {
+            isc_throw(BadValue, "Packet is null");
+        }
+        static_cast<void>(sent_packets_.template get<0>().push_back(packet));
+        ++sent_packets_num_;
+    }
+
+    /// \brief Add new packet to list of received packets.
+    ///
+    /// Method adds new packet to list of received packets.
+    ///
+    /// \param packet packet object to be added.
+    /// \throw isc::BadValue if packet is null.
+    void appendRcvd(const dhcp::PktPtr& packet) {
+        if (!packet) {
+            isc_throw(BadValue, "Packet is null");
+        }
+        static_cast<void>(rcvd_packets_.push_back(packet));
+    }
+
+    ///  \brief Update delay counters.
+    ///
+    /// Method updates delay counters based on timestamps of
+    /// sent and received packets.
+    ///
+    /// \param sent_packet sent packet
+    /// \param rcvd_packet received packet
+    /// \throw isc::BadValue if sent or received packet is null.
+    /// \throw isc::Unexpected if failed to calculate timestamps
+    void updateDelays(const dhcp::PktPtr& sent_packet,
+                      const dhcp::PktPtr& rcvd_packet);
+
+    /// \brief Match received packet with the corresponding sent packet.
+    ///
+    /// Method finds packet with specified transaction id on the list
+    /// of sent packets. It is used to match received packet with
+    /// corresponding sent packet.
+    /// Since packets from the server most often come in the same order
+    /// as they were sent by client, this method will first check if
+    /// next sent packet matches. If it doesn't, function will search
+    /// the packet using indexing by transaction id. This reduces
+    /// packet search time significantly.
+    ///
+    /// \param rcvd_packet received packet to be matched with sent packet.
+    /// \throw isc::BadValue if received packet is null.
+    /// \return packet having specified transaction or NULL if packet
+    /// not found
+    dhcp::PktPtr matchPackets(const dhcp::PktPtr& rcvd_packet);
+
+    /// \brief Return minimum delay between sent and received packet.
+    ///
+    /// Method returns minimum delay between sent and received packet.
+    ///
+    /// \return minimum delay between packets.
+    double getMinDelay() const { return(min_delay_); }
+
+    /// \brief Return maximum delay between sent and received packet.
+    ///
+    /// Method returns maximum delay between sent and received packet.
+    ///
+    /// \return maximum delay between packets.
+    double getMaxDelay() const { return(max_delay_); }
+
+    /// \brief Return average packet delay.
+    ///
+    /// Method returns average packet delay. If no packets have been
+    /// received for this exchange avg delay can't be calculated and
+    /// thus method throws exception.
+    ///
+    /// \throw isc::InvalidOperation if no packets for this exchange
+    /// have been received yet.
+    /// \return average packet delay.
+    double getAvgDelay() const {
+        if (rcvd_packets_num_  == 0) {
+            isc_throw(InvalidOperation, "no packets received");
+        }
+        return(sum_delay_ / rcvd_packets_num_);
+    }
+
+    /// \brief Return standard deviation of packet delay.
+    ///
+    /// Method returns standard deviation of packet delay. If no
+    /// packets have been received for this exchange, the standard
+    /// deviation can't be calculated and thus method throws
+    /// exception.
+    ///
+    /// \throw isc::InvalidOperation if number of received packets
+    /// for the exchange is equal to zero.
+    /// \return standard deviation of packet delay.
+    double getStdDevDelay() const {
+        if (rcvd_packets_num_ == 0) {
+            isc_throw(InvalidOperation, "no packets received");
+        }
+        return(sqrt(sum_delay_squared_ / rcvd_packets_num_ -
+                    getAvgDelay() * getAvgDelay()));
+    }
+
+    /// \brief Return number of orphan packets.
+    ///
+    /// Method returns number of received packets that had no matching
+    /// sent packet. It is possible that such packet was late or not
+    /// for us.
+    ///
+    /// \return number of orphan received packets.
+    uint64_t getOrphans() const { return(orphans_); }
+
+    /// \brief Return number of garbage collected packets.
+    ///
+    /// Method returns number of garbage collected timed out
+    /// packets. Packet is assumed timed out when duration
+    /// between sending it to server and receiving server's
+    /// response is greater than value specified with -d<value>
+    /// command line argument.
+    ///
+    /// \return number of garbage collected packets.
+    uint64_t getCollectedNum() const { return(collected_); }
+
+    /// \brief Return average unordered lookup set size.
+    ///
+    /// Method returns average unordered lookup set size.
+    /// This value changes every time \ref ExchangeStats::matchPackets
+    /// function performs unordered packet lookup.
+    ///
+    /// \throw isc::InvalidOperation if there have been no unordered
+    /// lookups yet.
+    /// \return average unordered lookup set size.
+    double getAvgUnorderedLookupSetSize() const {
+        if (unordered_lookups_ == 0) {
+            isc_throw(InvalidOperation, "no unordered lookups");
+        }
+        return(static_cast<double>(unordered_lookup_size_sum_) /
+               static_cast<double>(unordered_lookups_));
+    }
+
+    /// \brief Return number of unordered sent packets lookups.
+    ///
+    /// Method returns number of unordered sent packet lookups.
+    /// Unordered lookup is used when received packet was sent
+    /// out of order by server - transaction id of received
+    /// packet does not match transaction id of next sent packet.
+    ///
+    /// \return number of unordered lookups.
+    uint64_t getUnorderedLookups() const { return(unordered_lookups_); }
+
+    /// \brief Return number of ordered sent packets lookups.
+    ///
+    /// Method returns number of ordered sent packet lookups.
+    /// Ordered lookup is used when packets are received in the
+    /// same order as they were sent to the server.
+    /// If packets are skipped or received out of order, lookup
+    /// function will use unordered lookup (with hash table).
+    ///
+    /// \return number of ordered lookups.
+    uint64_t getOrderedLookups() const { return(ordered_lookups_); }
+
+    /// \brief Return total number of sent packets.
+    ///
+    /// Method returns total number of sent packets.
+    ///
+    /// \return number of sent packets.
+    uint64_t getSentPacketsNum() const { return(sent_packets_num_); }
+
+    /// \brief Return total number of received packets.
+    ///
+    /// Method returns total number of received packets.
+    ///
+    /// \return number of received packets.
+    uint64_t getRcvdPacketsNum() const { return(rcvd_packets_num_); }
+
+    /// \brief Return number of dropped packets.
+    ///
+    /// Method returns number of dropped packets.
+    ///
+    /// \return number of dropped packets.
+    uint64_t getDroppedPacketsNum() const {
+        uint64_t drops = 0;
+        if (getSentPacketsNum() > getRcvdPacketsNum()) {
+            drops = getSentPacketsNum() - getRcvdPacketsNum();
+        }
+        return(drops);
+    }
+
+    /// \brief Return total number of rejected leases.
+    ///
+    /// Method returns total number of rejected leases.
+    ///
+    /// \return number of rejected leases.
+    uint64_t getRejLeasesNum() const { return(rejected_leases_num_); }
+
+    /// \brief Return total number of non unique addresses.
+    ///
+    /// Method returns total number of non unique addresses.
+    ///
+    /// \return number of non unique addresses.
+    uint64_t getNonUniqueAddrNum() const { return(non_unique_addr_num_); }
+
+    /// \brief Increase number of rejected leases.
+    ///
+    /// Method increases total number of rejected leases by one.
+    void updateRejLeases() { ++rejected_leases_num_; }
+
+    /// \brief Increase number of non unique addresses.
+    ///
+    /// Method increases total number of non unique addresses by one.
+    void updateNonUniqueAddr() { ++non_unique_addr_num_; }
+
+    /// \brief Print main statistics for packet exchange.
+    ///
+    /// Method prints main statistics for particular exchange.
+    /// Statistics includes: number of sent and received packets,
+    /// number of dropped packets and number of orphans.
+    ///
+    /// \todo Currently the number of orphans is not displayed because
+    /// Reply messages received for Renew and Releases are counted as
+    /// orphans for the 4-way exchanges, which is wrong. We will need to
+    /// move the orphans counting out of the Statistics Manager so as
+    /// orphans counter is increased only if the particular message is
+    /// not identified as a response to any of the messages sent by
+    /// perfdhcp.
+    void printMainStats() const {
+        using namespace std;
+        auto sent = getSentPacketsNum();
+        auto drops = getDroppedPacketsNum();
+        double drops_ratio = 100.0 * static_cast<double>(drops) / static_cast<double>(sent);
+
+        cout << "sent packets: " << sent << endl
+             << "received packets: " << getRcvdPacketsNum() << endl
+             << "drops: " << drops << endl
+             << "drops ratio: " << drops_ratio << " %" << endl
+             << "orphans: " << getOrphans() << endl
+             << "rejected leases: " << getRejLeasesNum() << endl
+             << "non unique addresses: " << getNonUniqueAddrNum() << endl;
+    }
+
+    /// \brief Print round trip time packets statistics.
+    ///
+    /// Method prints round trip time packets statistics. Statistics
+    /// includes minimum packet delay, maximum packet delay, average
+    /// packet delay and standard deviation of delays. Packet delay
+    /// is a duration between sending a packet to server and receiving
+    /// response from server.
+    void printRTTStats() const {
+        using namespace std;
+        try {
+            cout << fixed << setprecision(3)
+                 << "min delay: " << getMinDelay() * 1e3 << " ms" << endl
+                 << "avg delay: " << getAvgDelay() * 1e3 << " ms" << endl
+                 << "max delay: " << getMaxDelay() * 1e3 << " ms" << endl
+                 << "std deviation: " << getStdDevDelay() * 1e3 << " ms"
+                 << endl
+                 << "collected packets: " << getCollectedNum() << endl;
+        } catch (const Exception&) {
+            // repeated output for easier automated parsing
+            cout << "min delay: n/a" << endl
+                 << "avg delay: n/a" << endl
+                 << "max delay: n/a" << endl
+                 << "std deviation: n/a" << endl
+                 << "collected packets: 0" << endl;
+        }
+    }
+
+    //// \brief Print timestamps for sent and received packets.
+    ///
+    /// Method prints timestamps for all sent and received packets for
+    /// packet exchange. In order to run this method the packets
+    /// archiving mode has to be enabled during object constructions.
+    /// Otherwise sent packets are not stored during tests execution
+    /// and this method has no ability to get and print their timestamps.
+    ///
+    /// \throw isc::InvalidOperation if found packet with no timestamp or
+    /// if packets archive mode is disabled.
+    void printTimestamps();
+
+    std::tuple<PktListIterator, PktListIterator> getSentPackets() {
+        return(std::make_tuple(sent_packets_.begin(), sent_packets_.end()));
+    }
+
+    /// \brief Return the list of received leases in CSV format as string.
+    ///
+    /// Depending exchange type, it can apply to
+    /// potential leases received in offers and advertisements,
+    /// committed leases received in acknowledgements and replies,
+    /// renewed or released leases.
+    ///
+    /// \return multiline string of received leases in CSV format
+    std::string receivedLeases() const;
+
+    /// \brief Print the list of received leases.
+    void printLeases() const;
+
+    static int malformed_pkts_;
+
+// Private stuff of ExchangeStats class
+private:
+
+    /// \brief Private default constructor.
+    ///
+    /// Default constructor is private because we want the client
+    /// class to specify exchange type explicitly.
+    ExchangeStats();
+
+    /// \brief Erase packet from the list of sent packets.
+    ///
+    /// Method erases packet from the list of sent packets.
+    ///
+    /// \param it iterator pointing to packet to be erased.
+    /// \return iterator pointing to packet following erased
+    /// packet or sent_packets_.end() if packet not found.
+    PktListIterator eraseSent(const PktListIterator it) {
+        if (archive_enabled_) {
+            // We don't want to keep list of all sent packets
+            // because it will affect packet lookup performance.
+            // If packet is matched with received packet we
+            // move it to list of archived packets. List of
+            // archived packets may be used for diagnostics
+            // when test is completed.
+            static_cast<void>(archived_packets_.push_back(*it));
+        }
+        // get<0>() template returns sequential index to
+        // container.
+        return(sent_packets_.template get<0>().erase(it));
+    }
+
+    ExchangeType xchg_type_;             ///< Packet exchange type.
+    PktList sent_packets_;               ///< List of sent packets.
+
+    /// Iterator pointing to the packet on sent list which will most
+    /// likely match next received packet. This is based on the
+    /// assumption that server responds in order to incoming packets.
+    PktListIterator next_sent_;
+
+    PktList rcvd_packets_;         ///< List of received packets.
+
+    /// List of archived packets. All sent packets that have
+    /// been matched with received packet are moved to this
+    /// list for diagnostics purposes.
+    PktList archived_packets_;
+
+    /// Indicates all packets have to be preserved after matching.
+    /// By default this is disabled which means that when received
+    /// packet is matched with sent packet both are deleted. This
+    /// is important when test is executed for extended period of
+    /// time and high memory usage might be the issue.
+    /// When timestamps listing is specified from the command line
+    /// (using diagnostics selector), all packets have to be preserved
+    /// so as the printing method may read their timestamps and
+    /// print it to user. In such usage model it will be rare to
+    /// run test for extended period of time so it should be fine
+    /// to keep all packets archived throughout the test.
+    bool archive_enabled_;
+
+    /// Maximum time elapsed between sending and receiving packet
+    /// before packet is assumed dropped.
+    double drop_time_;
+
+    double min_delay_;             ///< Minimum delay between sent
+                                   ///< and received packets.
+    double max_delay_;             ///< Maximum delay between sent
+                                   ///< and received packets.
+    double sum_delay_;             ///< Sum of delays between sent
+                                   ///< and received packets.
+    double sum_delay_squared_;     ///< Squared sum of delays between
+                                   ///< sent and received packets.
+
+    uint64_t orphans_;   ///< Number of orphan received packets.
+
+    uint64_t collected_; ///< Number of garbage collected packets.
+
+    /// Sum of unordered lookup sets. Needed to calculate mean size of
+    /// lookup set. It is desired that number of unordered lookups is
+    /// minimal for performance reasons. Tracking number of lookups and
+    /// mean size of the lookup set should give idea of packets search
+    /// complexity.
+    uint64_t unordered_lookup_size_sum_;
+
+    uint64_t unordered_lookups_;   ///< Number of unordered sent packets
+                                   ///< lookups.
+    uint64_t ordered_lookups_;     ///< Number of ordered sent packets
+                                   ///< lookups.
+
+    uint64_t sent_packets_num_;    ///< Total number of sent packets.
+    uint64_t rcvd_packets_num_;    ///< Total number of received packets.
+
+    uint64_t non_unique_addr_num_; ///< Total number of non unique addresses
+                                   ///< offered/advertised.
+    uint64_t rejected_leases_num_; ///< Total number of rejected leases
+                                   /// (e.g. NoAddrAvail)
+    boost::posix_time::ptime boot_time_; ///< Time when test is started.
+};
+
+/// Pointer to ExchangeStats.
+typedef boost::shared_ptr<ExchangeStats> ExchangeStatsPtr;
+
+/// Map containing all specified exchange types.
+typedef typename std::map<ExchangeType, ExchangeStatsPtr> ExchangesMap;
+
+/// Iterator pointing to \ref ExchangesMap.
+typedef typename ExchangesMap::const_iterator ExchangesMapIterator;
+
+
+/// \brief Statistics Manager
+///
+/// This class template is a storage for various performance statistics
+/// collected during performance tests execution with perfdhcp tool.
+///
+/// Statistics Manager holds lists of sent and received packets and
+/// groups them into exchanges. For example: DHCPDISCOVER message and
+/// corresponding DHCPOFFER messages belong to one exchange, DHCPREQUEST
+/// and corresponding DHCPACK message belong to another exchange etc.
+/// In order to update statistics for a particular exchange type, client
+/// class passes sent and received packets. Internally, Statistics Manager
+/// tries to match transaction id of received packet with sent packet
+/// stored on the list of sent packets. When packets are matched the
+/// round trip time can be calculated.
+///
+class StatsMgr : public boost::noncopyable {
+public:
+    /// \brief Constructor.
+    ///
+    /// This constructor by default disables packets archiving mode.
+    /// In this mode all packets from the list of sent packets are
+    /// moved to list of archived packets once they have been matched
+    /// with received packets. This is required if it has been selected
+    /// from the command line to print timestamps for all packets after
+    /// the test. If this is not selected archiving should be disabled
+    /// for performance reasons and to avoid waste of memory for storing
+    /// large list of archived packets.
+    StatsMgr(CommandOptions& options);
+
+    /// \brief Specify new exchange type.
+    ///
+    /// This method creates new \ref ExchangeStats object that will
+    /// collect statistics data from packets exchange of the specified
+    /// type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \param drop_time maximum time elapsed before packet is
+    /// assumed dropped. Negative value disables it.
+    /// \throw isc::BadValue if exchange of specified type exists.
+    void addExchangeStats(const ExchangeType xchg_type,
+                          const double drop_time = -1) {
+        if (exchanges_.find(xchg_type) != exchanges_.end()) {
+            isc_throw(BadValue, "Exchange of specified type already added.");
+        }
+        exchanges_[xchg_type] =
+            ExchangeStatsPtr(new ExchangeStats(xchg_type,
+                                               drop_time,
+                                               archive_enabled_,
+                                               boot_time_));
+    }
+
+    /// \brief Check if the exchange type has been specified.
+    ///
+    /// This method checks if the \ref ExchangeStats object of a particular type
+    /// exists (has been added using \ref addExchangeStats function).
+    ///
+    /// \param xchg_type A type of the exchange being represented by the
+    /// \ref ExchangeStats object.
+    ///
+    /// \return true if the \ref ExchangeStats object has been added for a
+    /// specified exchange type.
+    bool hasExchangeStats(const ExchangeType xchg_type) const {
+        return (exchanges_.find(xchg_type) != exchanges_.end());
+    }
+
+    /// \brief Add named custom uint64 counter.
+    ///
+    /// Method creates new named counter and stores in counter's map under
+    /// key specified here as short_name.
+    ///
+    /// \param short_name key to use to access counter in the map.
+    /// \param long_name name of the counter presented in the log file.
+    void addCustomCounter(const std::string& short_name,
+                          const std::string& long_name) {
+        if (custom_counters_.find(short_name) != custom_counters_.end()) {
+            isc_throw(BadValue,
+                      "Custom counter " << short_name << " already added.");
+        }
+        custom_counters_[short_name] =
+            CustomCounterPtr(new CustomCounter(long_name));
+    }
+
+    /// \brief Check if any packet drops occurred.
+    ///
+    // \return true, if packet drops occurred.
+    bool droppedPackets() const {
+        for (ExchangesMapIterator it = exchanges_.begin();
+             it != exchanges_.end();
+             ++it) {
+            if (it->second->getDroppedPacketsNum() > 0) {
+                return (true);
+            }
+        }
+        return (false);
+    }
+
+    /// \brief Return specified counter.
+    ///
+    /// Method returns specified counter.
+    ///
+    /// \param counter_key key pointing to the counter in the counters map.
+    /// The short counter name has to be used to access counter.
+    /// \return pointer to specified counter object.
+    CustomCounterPtr getCounter(const std::string& counter_key) {
+        CustomCountersMapIterator it = custom_counters_.find(counter_key);
+        if (it == custom_counters_.end()) {
+            isc_throw(BadValue,
+                      "Custom counter " << counter_key << "does not exist");
+        }
+        return(it->second);
+    }
+
+    /// \brief Increment specified counter.
+    ///
+    /// Increment counter value by one.
+    ///
+    /// \param counter_key key pointing to the counter in the counters map.
+    /// \param value value to increment counter by.
+    /// \return pointer to specified counter after incrementation.
+    const CustomCounter& incrementCounter(const std::string& counter_key,
+                                          const uint64_t value = 1) {
+        CustomCounterPtr counter = getCounter(counter_key);
+        *counter += value;
+        return (*counter);
+    }
+
+    /// \brief Adds new packet to the sent packets list.
+    ///
+    /// Method adds new packet to the sent packets list.
+    /// Packets are added to the list sequentially and
+    /// most often read sequentially.
+    ///
+    /// \param xchg_type exchange type.
+    /// \param packet packet to be added to the list
+    /// \throw isc::BadValue if invalid exchange type specified or
+    /// packet is null.
+    void passSentPacket(const ExchangeType xchg_type,
+                        const dhcp::PktPtr& packet) {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        xchg_stats->appendSent(packet);
+    }
+
+    /// \brief Add new received packet and match with sent packet.
+    ///
+    /// Method adds new packet to the list of received packets. It
+    /// also searches for corresponding packet on the list of sent
+    /// packets. When packets are matched the statistics counters
+    /// are updated accordingly for the particular exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \param packet received packet
+    /// \throw isc::BadValue if invalid exchange type specified
+    /// or packet is null.
+    /// \throw isc::Unexpected if corresponding packet was not
+    /// found on the list of sent packets.
+    dhcp::PktPtr
+    passRcvdPacket(const ExchangeType xchg_type,
+                   const dhcp::PktPtr& packet) {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        dhcp::PktPtr sent_packet = xchg_stats->matchPackets(packet);
+
+        if (sent_packet) {
+            xchg_stats->updateDelays(sent_packet, packet);
+            if (archive_enabled_) {
+                xchg_stats->appendRcvd(packet);
+            }
+        }
+        return(sent_packet);
+    }
+
+    /// \brief Return minimum delay between sent and received packet.
+    ///
+    /// Method returns minimum delay between sent and received packet
+    /// for specified exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return minimum delay between packets.
+    double getMinDelay(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getMinDelay());
+    }
+
+    /// \brief Return maximum delay between sent and received packet.
+    ///
+    /// Method returns maximum delay between sent and received packet
+    /// for specified exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return maximum delay between packets.
+    double getMaxDelay(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getMaxDelay());
+    }
+
+    /// \brief Return average packet delay.
+    ///
+    /// Method returns average packet delay for specified
+    /// exchange type.
+    ///
+    /// \return average packet delay.
+    double getAvgDelay(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getAvgDelay());
+    }
+
+    /// \brief Return standard deviation of packet delay.
+    ///
+    /// Method returns standard deviation of packet delay
+    /// for specified exchange type.
+    ///
+    /// \return standard deviation of packet delay.
+    double getStdDevDelay(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getStdDevDelay());
+    }
+
+    /// \brief Return number of orphan packets.
+    ///
+    /// Method returns number of orphan packets for specified
+    /// exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of orphan packets so far.
+    uint64_t getOrphans(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getOrphans());
+    }
+
+    /// \brief Return average unordered lookup set size.
+    ///
+    /// Method returns average unordered lookup set size.
+    /// This value changes every time \ref ExchangeStats::matchPackets
+    /// function performs unordered packet lookup.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return average unordered lookup set size.
+    double getAvgUnorderedLookupSetSize(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getAvgUnorderedLookupSetSize());
+    }
+
+    /// \brief Return number of unordered sent packets lookups.
+    ///
+    /// Method returns number of unordered sent packet lookups.
+    /// Unordered lookup is used when received packet was sent
+    /// out of order by server - transaction id of received
+    /// packet does not match transaction id of next sent packet.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of unordered lookups.
+    uint64_t getUnorderedLookups(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getUnorderedLookups());
+    }
+
+    /// \brief Return number of ordered sent packets lookups.
+    ///
+    /// Method returns number of ordered sent packet lookups.
+    /// Ordered lookup is used when packets are received in the
+    /// same order as they were sent to the server.
+    /// If packets are skipped or received out of order, lookup
+    /// function will use unordered lookup (with hash table).
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of ordered lookups.
+    uint64_t getOrderedLookups(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getOrderedLookups());
+    }
+
+    /// \brief Return total number of sent packets.
+    ///
+    /// Method returns total number of sent packets for specified
+    /// exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of sent packets.
+    uint64_t getSentPacketsNum(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getSentPacketsNum());
+    }
+
+    /// \brief Return total number of received packets.
+    ///
+    /// Method returns total number of received packets for specified
+    /// exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of received packets.
+    uint64_t getRcvdPacketsNum(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getRcvdPacketsNum());
+    }
+
+    /// \brief Return total number of dropped packets.
+    ///
+    /// Method returns total number of dropped packets for specified
+    /// exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of dropped packets.
+    uint64_t getDroppedPacketsNum(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getDroppedPacketsNum());
+    }
+
+    /// \brief Return number of garbage collected packets.
+    ///
+    /// Method returns number of garbage collected timed out
+    /// packets. Packet is assumed timed out when duration
+    /// between sending it to server and receiving server's
+    /// response is greater than value specified with -d<value>
+    /// command line argument.
+    ///
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of garbage collected packets.
+    uint64_t getCollectedNum(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getCollectedNum());
+    }
+
+    /// \brief Return total number of rejected leases.
+    ///
+    /// Method returns total number of rejected leases for specified
+    /// exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of rejected leases.
+    uint64_t getRejLeasesNum(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getRejLeasesNum());
+    }
+
+    /// \brief Increase total number of rejected leases.
+    ///
+    /// Method increases total number of rejected leases by one
+    /// for specified exchange type.
+    void updateRejLeases(const ExchangeType xchg_type) {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        xchg_stats->updateRejLeases();
+    }
+
+    /// \brief Increase total number of non unique addresses.
+    ///
+    /// Method increases total number of non unique addresses or
+    /// prefixes by one for specified exchange type.
+    void updateNonUniqueAddrNum(const ExchangeType xchg_type) {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        xchg_stats->updateNonUniqueAddr();
+    }
+
+    /// \brief Return total number of non unique addresses.
+    ///
+    /// Method returns total number of non unique addresses and/or
+    /// prefixes for specified exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return number of non unique addresses.
+    uint64_t getNonUniqueAddrNum(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        return(xchg_stats->getNonUniqueAddrNum());
+    }
+
+    /// \brief Get time period since the start of test.
+    ///
+    /// Calculate dna return period since the test start. This
+    /// can be specifically helpful when calculating packet
+    /// exchange rates.
+    ///
+    /// \return test period so far.
+    boost::posix_time::time_period getTestPeriod() const {
+        using namespace boost::posix_time;
+        time_period test_period(boot_time_,
+                                microsec_clock::universal_time());
+        return test_period;
+    }
+
+    /// \brief Print statistics counters for all exchange types.
+    ///
+    /// Method prints statistics for all exchange types.
+    /// Statistics includes:
+    /// - number of sent and received packets
+    /// - number of dropped packets and number of orphans
+    /// - minimum packets delay,
+    /// - average packets delay,
+    /// - maximum packets delay,
+    /// - standard deviation of packets delay.
+    ///
+    /// \throw isc::InvalidOperation if no exchange type added to
+    /// track statistics.
+    void printStats() const {
+        if (exchanges_.empty()) {
+            isc_throw(isc::InvalidOperation,
+                      "no exchange type added for tracking");
+        }
+        for (ExchangesMapIterator it = exchanges_.begin();
+             it != exchanges_.end();
+             ++it) {
+            ExchangeStatsPtr xchg_stats = it->second;
+            std::cout << "***Statistics for: " << it->first
+                      << "***" << std::endl;
+            xchg_stats->printMainStats();
+            std::cout << std::endl;
+            xchg_stats->printRTTStats();
+            std::cout << std::endl;
+        }
+    }
+
+    /// \brief Print intermediate statistics.
+    ///
+    /// Method prints intermediate statistics for all exchanges.
+    /// Statistics includes sent, received and dropped packets
+    /// counters.
+    ///
+    /// \param clean_report value to generate easy to parse report.
+    /// \param clean_sep string used as separator if clean_report enabled..
+    void
+    printIntermediateStats(bool clean_report, std::string clean_sep) const {
+        std::ostringstream stream_sent;
+        std::ostringstream stream_rcvd;
+        std::ostringstream stream_drops;
+        std::ostringstream stream_reject;
+        std::string sep("");
+        for (ExchangesMapIterator it = exchanges_.begin();
+             it != exchanges_.end(); ++it) {
+
+            if (it != exchanges_.begin()) {
+                if (clean_report) {
+                    sep = clean_sep;
+                } else {
+                    sep = "/";
+                }
+            }
+            stream_sent << sep << it->second->getSentPacketsNum();
+            stream_rcvd << sep << it->second->getRcvdPacketsNum();
+            stream_drops << sep << it->second->getDroppedPacketsNum();
+            stream_reject << sep << it->second->getRejLeasesNum();
+        }
+
+        if (clean_report) {
+        std::cout << stream_sent.str()
+                  << clean_sep << stream_rcvd.str()
+                  << clean_sep << stream_drops.str()
+                  << clean_sep << stream_reject.str()
+                  << std::endl;
+
+        } else {
+        std::cout << "sent: " << stream_sent.str()
+                  << "; received: " << stream_rcvd.str()
+                  << "; drops: " << stream_drops.str()
+                  << "; rejected: " << stream_reject.str()
+                  << std::endl;
+        }
+    }
+
+    /// \brief Print timestamps of all packets.
+    ///
+    /// Method prints timestamps of all sent and received
+    /// packets for all defined exchange types.
+    ///
+    /// \throw isc::InvalidOperation if one of the packets has
+    /// no timestamp value set or if packets archive mode is
+    /// disabled.
+    ///
+    /// \throw isc::InvalidOperation if no exchange type added to
+    /// track statistics or packets archive mode is disabled.
+    void printTimestamps() const {
+        if (exchanges_.empty()) {
+            isc_throw(isc::InvalidOperation,
+                      "no exchange type added for tracking");
+        }
+        for (ExchangesMapIterator it = exchanges_.begin();
+             it != exchanges_.end();
+             ++it) {
+            ExchangeStatsPtr xchg_stats = it->second;
+            std::cout << "***Timestamps for packets: "
+                      << it->first
+                      << "***" << std::endl;
+            xchg_stats->printTimestamps();
+            std::cout << std::endl;
+        }
+    }
+
+    /// \brief Delegate to all exchanges to print their leases.
+    void printLeases() const;
+
+    /// \brief Print names and values of custom counters.
+    ///
+    /// Method prints names and values of custom counters. Custom counters
+    /// are defined by client class for tracking different statistics.
+    ///
+    /// \throw isc::InvalidOperation if no custom counters added for tracking.
+    void printCustomCounters() const {
+        if (custom_counters_.empty()) {
+            isc_throw(isc::InvalidOperation, "no custom counters specified");
+        }
+        for (CustomCountersMapIterator it = custom_counters_.begin();
+             it != custom_counters_.end();
+             ++it) {
+            CustomCounterPtr counter = it->second;
+            std::cout << counter->getName() << ": " << counter->getValue()
+                      << std::endl;
+        }
+    }
+
+    std::tuple<typename ExchangeStats::PktListIterator, typename ExchangeStats::PktListIterator> getSentPackets(const ExchangeType xchg_type) const {
+        ExchangeStatsPtr xchg_stats = getExchangeStats(xchg_type);
+        std::tuple<typename ExchangeStats::PktListIterator, typename ExchangeStats::PktListIterator> sent_packets_its = xchg_stats->getSentPackets();
+        return(sent_packets_its);
+    }
+
+private:
+
+    /// \brief Return exchange stats object for given exchange type.
+    ///
+    /// Method returns exchange stats object for given exchange type.
+    ///
+    /// \param xchg_type exchange type.
+    /// \throw isc::BadValue if invalid exchange type specified.
+    /// \return exchange stats object.
+    ExchangeStatsPtr getExchangeStats(const ExchangeType xchg_type) const {
+        ExchangesMapIterator it = exchanges_.find(xchg_type);
+        if (it == exchanges_.end()) {
+            isc_throw(BadValue, "Packets exchange not specified");
+        }
+        ExchangeStatsPtr xchg_stats = it->second;
+        return(xchg_stats);
+    }
+
+    ExchangesMap exchanges_;            ///< Map of exchange types.
+    CustomCountersMap custom_counters_; ///< Map with custom counters.
+
+    /// Indicates that packets from list of sent packets should be
+    /// archived (moved to list of archived packets) once they are
+    /// matched with received packets. This is required when it has
+    /// been selected from the command line to print packets'
+    /// timestamps after test. This may affect performance and
+    /// consume large amount of memory when the test is running
+    /// for extended period of time and many packets have to be
+    /// archived.
+    bool archive_enabled_;
+
+    boost::posix_time::ptime boot_time_; ///< Time when test is started.
+};
+
+/// Pointer to Statistics Manager;
+typedef boost::shared_ptr<StatsMgr> StatsMgrPtr;
+
+
+} // namespace perfdhcp
+} // namespace isc
+
+#endif // STATS_MGR_H