[5580] Added developor and admin doc

doc/Doxyfile

@@ -780,6 +780,7 @@ INPUT                  = ../src/bin/agent \
                          ../src/bin/lfc \
                          ../src/hooks/dhcp/user_chk \
                          ../src/hooks/dhcp/lease_cmds \
+                         ../src/hooks/dhcp/stat_cmds \
                          ../src/lib/asiodns \
                          ../src/lib/asiolink \
                          ../src/lib/cc \

doc/devel/mainpage.dox

@@ -54,6 +54,7 @@
  * - @subpage hooksmgMaintenanceGuide
  * - @subpage libdhcp_user_chk
  * - @subpage libdhcp_lease_cmds
+ * - @subpage libdhcp_stat_cmds
  *
  * @section dhcpMaintenanceGuide DHCP Maintenance Guide
  * - @subpage dhcp4

doc/guide/Makefile.am

@@ -8,7 +8,7 @@ dist_html_DATA = $(HTMLDOCS) kea-guide.css kea-logo-100x70.png
 DOCBOOK = kea-guide.xml intro.xml quickstart.xml install.xml admin.xml config.xml
 DOCBOOK += keactrl.xml dhcp4-srv.xml dhcp6-srv.xml lease-expiration.xml logging.xml
 DOCBOOK += ddns.xml hooks.xml libdhcp.xml lfc.xml stats.xml ctrl-channel.xml faq.xml
-DOCBOOK += hooks-host-cache.xml hooks-radius.xml
+DOCBOOK += hooks-host-cache.xml hooks-radius.xml hooks-stat-cmds.xml
 DOCBOOK += classify.xml shell.xml agent.xml
 
 EXTRA_DIST = $(DOCBOOK)

doc/guide/hooks-stat-cmds.xml

@@ -0,0 +1,283 @@
+<section xml:id="hooks-stat-cmds">
+  <title>stat_cmds: Supplemental Statistics Commands</title>
+  <para>
+    This library provides additional statistics commands for
+    retrieving lease statistics from kea-dhcp servers.  These commands
+    were added to address an issue with obtaining accurate lease
+    statistics in deployments running multiple Kea servers that use
+    shared lease back end.  The in-memory statistics kept by individual
+    servers only track lease changes made by that server.  Thus in a
+    deployment with multiple servers, these statistics are incomplete.
+    In Kea 1.4, the MySQL and PostgreSQL back ends were modified to track
+    lease allocation changes as they occur via database triggers. Additionally,
+    all four lease back ends were extended to support retrieving lease
+    statistics for all subnets, a single subnet, or a range of subnets.
+    Finally, this library was constructed to provide commands for retrieving
+    these statistics.  Additional statistics commands may be added to this
+    library in future releases.
+  </para>
+
+  <para>
+    The commands currently provided by this library are:
+  <itemizedlist>
+    <listitem>
+      <para><command>stat-lease4-get</command> - fetches DHCPv4 lease statistics</para>
+    </listitem>
+    <listitem>
+      <para><command>stat-lease6-get</command> - fetches DHCPv6 lease statistics</para>
+    </listitem>
+  </itemizedlist>
+  </para>
+
+  <para>
+    The Stat commands library is part of the open source code and is
+    available to every Kea user.
+  </para>
+
+  <para>
+    All commands use JSON syntax and can be issued either using directly to
+    the servers via the control channel (see <xref linkend="ctrl-channel"/>)
+    or via Control Agent (see <xref linkend="kea-ctrl-agent"/>).
+  </para>
+
+  <para>
+    This library may be loaded by both kea-dhcp4 and kea-dhcp6 servers.
+    It is loaded in the same way as other other libraries and currently has
+    no parameters:
+  </para>
+<para>
+<screen>
+"Dhcp6": { <userinput>
+    "hooks-libraries": [
+        {
+            "library": "/path/libdhcp_stat_cmds.so"
+        }
+        ...
+    ] </userinput>
+}
+</screen>
+</para>
+
+  <para>
+    In a deployment with multiple kea-dhcp servers sharing a common lease
+    storage, it may be loaded by any or all of the servers.  However, one
+    thing to keep in mind is that a server's response to a stat-lease{4/6}-get
+    command will only contain data for subnets known to that server.  In
+    other words, if subnet does not appear in a server's configuration, it
+    will not retrieve statistics for it.
+ </para>
+
+<section>
+  <title>stat-lease4-get, stat-lease6-get commands</title>
+    <para>
+      The <command>stat-lease4-get</command> and <command>stat-lease6-get</command>
+      commands fetch lease statistics for a range of known subnets.  The
+      range of subnets is determined through the use of optional command
+      input parameters:
+      <itemizedlist>
+          <listitem>
+            <para><command>subnet-id</command> - ID of the subnet for which
+            lease statistics should be fetched. Use this to get statistics for
+            a single subnet.  If the subnet does not exist the command result
+            code will be 2 (i.e. CONTROL_RESULT_EMPTY).
+            </para>
+          </listitem>
+          <listitem>
+            <para><command>subnet-range</command> - A pair of subnet IDs which
+            describe an inclusive range of subnets for which statistics should
+            be retrieved.  Note that fuzzy values are supported thus allowing
+            for a query for statistics using approximate ID values. If the
+            range does not include any known subnets, the command result code
+            will be 2 (i.e. CONTROL_RESULT_EMPTY).
+            <itemizedlist>
+              <listitem>
+                <command>first-subnet-id</command> - ID of the first
+                subnet in the range.
+              </listitem>
+              <listitem>
+                <command>last-subnet-id</command> - ID of the first
+                subnet in the range.
+              </listitem>
+            </itemizedlist>
+            </para>
+          </listitem>
+        </itemizedlist>
+        The use of subnet-id and subnet-range are mutually exclusive.
+        If no parameters are given, the result will contain data for all
+        known subnets.  Note that in configurations with large numbers of
+        subnets, this can be result in a large response.
+        <para>
+        The following command would fetch lease statistcis for all known subnets from kea-dhcp4 server:
+<screen>
+{
+  "command": "stat-lease4-get",
+  "arguments": {
+  }
+}
+</screen>
+</para>
+      <para>
+        The following command would fetch lease statistcis for subnet ID 10 from kea-dhcp6 server:
+<screen>
+{
+  "command": "stat-lease6-get",
+  "arguments": {
+    "subnet-id" : 10
+  }
+}
+</screen>
+</para>
+        <para>
+        The following command would fetch lease statistcis for all subnets from subnet ID 10 through 50 from kea-dhcp4 server:
+<screen>
+{
+  "command": "stat-lease4-get",
+  "arguments": {
+    "subnet-range" {
+      "first-subnet-id": 10,
+      "last-subnet-id": 50,
+    }
+  }
+}
+</screen>
+</para>
+
+<para>
+  The response to the either command will contain three elements:
+  <itemizedlist>
+    <listitem>
+      <para><command>result</command> - numeric value indicating the outcome of the
+        command where:
+        <itemizedlist>
+          <listitem><command>0</command> - command was successful</listitem>
+          <listitem><command>1</command> - an error occurred, an explanation will
+            be the "text" element</listitem>
+          <listitem><command>2</command> - indicates the fetch found no matching data</listitem>
+        </itemizedlist>
+      </para>
+    </listitem>
+    <listitem>
+      <para><command>text</command> - an explanation of the command outcome. When the command
+      succeeds it will contain the command name along with the number of rows returned.</para>
+    </listitem>
+    <listitem>
+      <para><command>arguments</command></para> - a map containing the data returned by the
+        command as the element "result-set", which patterned after SQL statement responses:
+      <itemizedlist>
+        <listitem><command>columns</command> - a list of text column labels.
+          The columns returned for DHCPv4 are:
+          <itemizedlist>
+            <listitem><command>subnet-id</command> - ID of the subnet</listitem>
+            <listitem><command>total-addresses</command> - total number of addresses
+              available for DHCPv4 management. In other words, this is the sum of all
+              addresses in all configured pools. This statistic changes only during
+              configuration changes. Note it does not take into account any addresses that
+              may be reserved due to host reservation.
+            </listitem>
+            <listitem><command>assigned-addresses</command> - number of assigned
+              addresses in a given subnet. It increases every time a new lease is
+              allocated (as a result of receiving a DHCPREQUEST message) and is decreased
+              every time a lease is released (a DHCPRELEASE message is received) or expires.
+            </listitem>
+            <listitem><command>declined-addresses</command> - number of IPv4 addresses
+              that are currently declined in a given subnet, so is a count of the number
+              of leases currently unavailable. Once a lease is recovered, this statistic
+              will be decreased. Ideally, this statistic should be zero. If this statistic
+              is non-zero (or worse increasing), a network administrator should investigate
+              if there is a misbehaving device in his network.
+            </listitem>
+          </itemizedlist>
+          The columns returned for DHCPv6 are:
+          <itemizedlist>
+            <listitem><command>subnet-id</command> - ID of the subnet</listitem>
+            <listitem><command>total-nas</command> - number of NA addresses available
+              for DHCPv6 management for a given subnet. In other words, this is the
+              sum of all addresses in all configured pools. This statistic changes
+              only during configuration changes. Note that it does not take into account
+              any addresses that may be reserved due to host reservation.
+            </listitem>
+            <listitem><command>assigned-nas</command> - number of NA addresses in a
+              the subnet that are assigned. This statistic increases every time a new
+              lease is allocated (as a result of receiving a REQUEST message) and is
+              decreased every time a lease is released (a RELEASE message is received)
+              or expires.
+            </listitem>
+            <listitem><command>declined-nas</command> - number of IPv6 addresses that
+              are currently declined and so counts the number of leases currently
+              unavailable. Once a lease is recovered, this statistic will be decreased.
+              Ideally, this statistic should be zero. If this statistic is non-zero
+              (or worse, increasing), the network administrator should investigate if
+              there is a misbehaving device in the network.
+            </listitem>
+            <listitem><command>total-pds</command> - total number of PD prefixes available
+              of DHCPv6 management for a given subnet. In other words, this is the sum
+              of all prefixes in all configured pools. This statistic changes only during
+              configuration changes. Note it does not take into account any prefixes that
+              may be reserved due to host reservation.
+            </listitem>
+            <listitem><command>assigned-pds</command> - number of PD prefixes in a given
+              subnet that are assigned. This statistic increases every time a new lease is
+              allocated (as a result of receiving a REQUEST message) and is decreased every
+              time a lease is released (a RELEASE message is received) or expires.
+            </listitem>
+          </itemizedlist>
+        </listitem>
+        <listitem><command>rows</command> - a list of rows, one per subnet ID. Each row
+          contains a data value for corresponding to and in the same order as each column
+          listed in "columns" for a given subnet.
+        </listitem>
+        <listitem><command>timestamp</command> - textual date and time the data was fetched,
+           expressed as GMT</listitem>
+      </itemizedlist>
+    </listitem>
+  </itemizedlist>
+<para>
+  The response to a DHCPv4 command might look as follows:
+<screen>
+  {
+    "result": 0,
+    "text": "stat-lease4-get: 2 rows found",
+    "arguments": {
+      "result-set": {
+        "columns": [ "subnet-id", "total-addresses", "assigned-addresses", "declined-addresses" ]
+        "rows": [
+          [ 10, 256, 111, 0 ], [ 20, 4098, 2034, 4 ]
+        ],
+      "timestamp": "2018-05-04 15:03:37.000000"
+      }
+    }
+  }
+</screen>
+</para>
+<para>
+  The response to a DHCPv6 command might look as follows:
+<screen>
+  {
+    "result": 0,
+    "text": "stat-lease6-get: 2 rows found",
+    "arguments": {
+      "result-set": {
+        "columns": [ "subnet-id", "total-nas", "assigned-nas", "declined-nas", "total-pds", "assigned-pds" ]
+        "rows": [
+          [ 10, 256, 111, 0 ],
+          [ 20, 4098, 2034, 4 ]
+        ],
+      "timestamp": "2018-05-04 15:03:37.000000"
+      }
+    }
+  }
+</screen>
+</para>
+
+
+
+</para>
+
+
+
+</para>
+
+
+
+</section>
+</section>

doc/guide/hooks.xml

@@ -2838,6 +2838,8 @@ both the command and the response.
 
     <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="hooks-host-cache.xml"/>
 
+    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="hooks-stat-cmds.xml"/>
+
   </section>
 
 

src/hooks/dhcp/stat_cmds/stat_cmds.cc

@@ -43,11 +43,11 @@ public:
         isc::Exception(file, line, what) { };
 };
 
-///@brief Implements command handlinge for stat-lease<x>-get commands
+///@brief Implements command handlinge for stat-leaseX-get commands
 class LeaseStatCmdsImpl : private CmdsImpl {
 public:
 
-    /// @brief Wrapper class stat-lease<x>-get command parameters.
+    /// @brief Wrapper class stat-leaseX-get command parameters.
     class Parameters {
     public:
         /// @brief Specifies the subnet-id for a single subnet, or
@@ -92,7 +92,7 @@ public:
     int
     statLease6GetHandler(CalloutHandle& handle);
 
-    /// @Brief Parses command arguments into stat-lease<x>-get parameters
+    /// @brief Parses command arguments into stat-leaseX-get parameters
     /// @param cmd_args Element form of command arguments to parse
     /// @throw BadValue if any of the following rules are broken:
     ///
@@ -165,17 +165,17 @@ public:
     /// @brief Adds a row of Lease4 stat values to a list of value rows
     ///
     /// @param[out] value_rows  list of rows to which to add
-    /// @param[out] subent_id  id of the subnet of the new row. This value is
+    /// @param[out] subnet_id  id of the subnet of the new row. This value is
     /// also used for fetching the total addresses in the subnet
     /// @param assigned number of assigned addresses in the subnet
-    /// @param assigned number of declined addresses in the subnet
+    /// @param declined number of declined addresses in the subnet
     void addValueRow4(ElementPtr value_rows, const SubnetID &subnet_id,
                       int64_t assigned, int64_t declined);
 
     /// @brief Adds a row of Lease6 stat values to a list of value rows
     ///
     /// @param[out] value_rows  list of rows to which to add
-    /// @param[out] subent_id  id of the subnet of the new row. This value is
+    /// @param[out] subnet_id  id of the subnet of the new row. This value is
     /// also used for fetching the total NAs and PDs in the subnet
     /// @param assigned number of assigned NAs in the subnet
     /// @param declined number of declined NAs in the subnet

src/hooks/dhcp/stat_cmds/stat_cmds.dox

@@ -21,78 +21,179 @@ particular its section about hooks.
 
 @section stat_cmds Stat Commands Overview
 
-Stat Commands (or stat_cmds) is a Hook library that can be loaded by Kea to
+Stat Commands (or stat_cmds) is a Hook library that can be loaded by
-extend it with additional mechanisms.
+either kea-dhcp4 and kea-dhcp6 servers to extend them with additional
+statistics mechanisms.
 
-The primary purpose of this library is to provide commands that manage leases.
+The initial purpose of this library is provide supplemental commands for
-As such, the whole library is structured around command handlers. When the
+obtaining accurate lease statistics in deployments that share lease storage
-library is loaded it registers a number of handlers for new commands.  When a
+between multiple Kea DHCP servers. It is likely that additional statistics
-command is issued (be it directly via control channel or indirectly via REST
+related commands will be added to this library in future releases as use
+cases for them arise.
+
+The library is structured around command handlers. When the library is
+loaded it registers handlers for new commands.  When a command
+is issued (be it directly via control channel or indirectly via REST
 interface from control agent), the code receives a JSON command with
-parameters. Those are parsed and then actual operation commences.  This
+parameters.  The command is routed the appropriate handler, its parameters
-operation always interacts with an instantiation of isc::dhcp::StatMgr
+are parsed and command executed accordingly.  Lastly, a response is
-instance, which is Kea's way of storing leases. At the time of writing this text
+constructed and shipped back to the client.
-(Aug. 2017), Kea supports four types of lease managers: memfile, MySQL,
-PostgreSQL or Cassandra. The lease commands provided by this library
-provide a unified interface for those backends.
 
-As with other hooks, this one also keeps its code in a separate namespace which
+This lease statistics commands interact with both the isc::dhcp::StatsMgr
+and the isc::dhcp::LeaseMgr instance.  At the time of writing this text
+(May, 2018), Kea supports four types of lease managers: memfile, MySQL,
+PostgreSQL or Cassandra. The lease statistics commands provided by this
+library provide a unified interface supported by all four of these backends.
+
+As with other hooks, this one keeps its code in a separate namespace which
 corresponds to the file name of the library: isc::stat_cmds.
 
+For background on the design and design choices please refer to: <a
+href="http://kea.isc.org/wiki/SharedLeaseStorageStats">Shared Lease Stats Design</a>
+
 @section stat_cmdsCode Stat Commands Code Overview
 
-The library operation starts with Kea calling the load() function (file
+Library operation starts with Kea calling the load() function (file
-load_unload.cc).  It instantiates an isc::stat_cmds::StatCmds object.
+stat_cmds_callouts.cc).  This function registers the command callout
-The constructor of that object registers all of the lease commands. For a list,
+functions for each of the libraries commands. For a list,
-see @ref isc::stat_cmds::StatCmds class documentation.  This class uses Pimpl
+see @ref isc::stat_cmds::StatCmds class documentation.  This class uses
-design pattern, thus the real implementation is hidden in isc::stat_cmds::StatCmdsImpl.
+the Pimpl design pattern, and thus the actual implementation is hidden
+in @ref isc::stat_cmds::LeaseStatCmdsImpl.
 
-Almost every command has its own handler, except few that share the same handler
+Unlike similar libraries, the Pimpl class is differentiated from the
-between v4 and v6 due to its similarity. For example
+the StatCmds class by the prefix "Lease" and it is instantiated in the outer
-isc::stat_cmds::StatCmdsImpl::leaseAddHandler handles lease4-add and lease6-add
+handler (e.g. @ref isc::stat_cmds::StatCmds::statLease4GetHandler) rather than
-commands. Although the details differ between handlers, the general approach
+the StatCmds constructor.  This was done in the event that commands, unrelated
-is the same. First, it starts with parameters sanitization and then some
+to lease statistics, are added to this library and that would be better served
-interaction with isc::dhcp::StatMgr is conducted.
+by Pimpl derviations specific to them.
 
-For commands that do something with a specific lease (lease4-get, lease6-get,
+@subsection stat_cmdsLeaseStatCode Lease Stat Commands Code Overview
-lease4-del, lease6-del), there is a @ref isc::stat_cmds::StatCmdsImpl::Parameters
-class that contains parsed elements.
 
-For details see documentation and code of the following handlers:
+There are two shared lease statistic commands, "stat-lease4-get" and "stat-lease6-get".
-- @ref isc::stat_cmds::StatCmdsImpl::leaseAddHandler (lease4-add, lease6-add)
+Both of these support the same input parameters and have their own command handlers:
-- @ref isc::stat_cmds::StatCmdsImpl::leaseGetHandler (lease4-get, lease6-get)
-- @ref isc::stat_cmds::StatCmdsImpl::lease4DelHandler (lease4-del)
-- @ref isc::stat_cmds::StatCmdsImpl::lease6DelHandler (lease6-del)
-- @ref isc::stat_cmds::StatCmdsImpl::lease4UpdateHandler (lease4-update)
-- @ref isc::stat_cmds::StatCmdsImpl::lease6UpdateHandler (lease6-update)
-- @ref isc::stat_cmds::StatCmdsImpl::lease4WipeHandler (lease4-wipe)
-- @ref isc::stat_cmds::StatCmdsImpl::lease6WipeHandler (lease6-wipe)
 
-@section stat_cmdsDesigns Stat Commands Design choices
+- @ref isc::stat_cmds::LeaseStatCmdsImpl::statLease4GetHandler (stat-lease4-get)
+- @ref isc::stat_cmds::LeaseStatCmdsImpl::statLease6GetHandler (stat-lease6-get)
 
-The lease manipulation commands were implemented to provide a convenient interface
+Briefly, the commands are intended to fetch the lease statistics per subnet
-for sysadmins. The primary goal was to offer a way to interact with the live
+for the range of subnets described by the input parameters.  JSON text structure
-lease database in unified way, regardless of the actual backend being used.
+of the commands is as follows:
 
-For some backends (MySQL, PostgreSQL and Cassandra) it is possible to interact
+DHCPv4 command:
-directly with the backend while Kea is running and possibly change its content. This
-ability is both powerful and dangerous. In particular, only rudimentary
-checks are enforced by the DB schemas (e.g. not possible to have two leases
-for the same address). However, it does not prevent sysadmins from making
-more obscure errors, like inserting leases for subnets that do not exist
-or configuring an address that is topologically outside of the subnet to which
-it should belong. These kind of checks are only possible by DHCP-aware
-code, which this library provides.
 
-Some of the queries may require a seemingly odd set of parameters. For example,
+@code
-lease6-get query requires at least DUID, subnet-id and IAID to retrieve a lease
+{
-by DUID. The need for a sysadmin to know and specify an IAID is troublesome.
+    "command": "stat-lease4-get",
-However, the guiding principle here was to use whatever queries were already
+    "arguments": {
-exposed by the lease manager and not introduce new indexes, unless absolutely
+        "subnet-id": x
-necessary. This ensures that there is no performance degradation when the
+        "subnet-range": {
-library is loaded. The only exception for that was lease4-wipe and lease6-wipe
+            "first-subnet-id": x,
-commands that remove all leases from specific subnet. As there were no
+            "last-subnet-id": y
-queries that could retrieve or otherwise enumerate leases for a specific subnet,
+        }
-a new query type and a new index had to be added.
+    }
+}
+
+    where subnet-id and subnet-range are optional and mutually exclusive
+@endcode
+
+DHCPv6 command:
+
+@code
+{
+    "command": "stat-lease6-get",
+    "arguments": {
+        "subnet-id": x
+        "subnet-range": {
+            "first-subnet-id": x,
+            "last-subnet-id": y
+        }
+    }
+}
+
+    where subnet-id and subnet-range are optional and mutually exclusive
+@endcode
+
+
+
+Command handling
+for both commands is symetrical consists of the following steps:
+
+-# The input parameters (if any) are parsed.  Invalid values or
+combinations if detected result in generating a CONTROL_RESULT_ERROR
+response to the client.  (See @ref isc::stat_cmds::LeaseStatCmdsImpl::getParameters
+and @ref isc::stat_cmds::LeaseStatCmdsImpl::Parameters)
+
+-# The parameters are used to identify the range of configured subnets
+to include in the response.  This is done by querying subnet configuration
+housed by @ref isc::dhcp::CfgMgr. If the range contains no known subnets then a
+CONTROL_RESULT_EMPTY response is sent back to the client.
+
+-# The initial result-set response is constructed.  Essentially this is
+an @ref isc::data::Element tree, which converted to JSON would appear as follows:
+
+@code
+    "result-set": {
+        "timestamp": "2018-03-22 09:43:30.815371",
+        "columns": ["<label-1>, <label-2>, ... ],
+        "rows": []
+    }
+@endcode
+
+-# The acutal lease statistics are then retrieved from @ref isc::dhcp::LeaseMgr instance
+by invoking of the three functions based on the input parameters:
+
+DHCPv4 functions:
+
+- @ref isc::dhcp::LeaseMgr::startLeaseStatsQuery4
+- @ref isc::dhcp::LeaseMgr::startSubnetLeaseStatsQuery4
+- @ref isc::dhcp::LeaseMgr::startSubnetRangeLeaseStatsQuery4
+
+DHCPv6 functions:
+
+- @ref isc::dhcp::LeaseMgr::startLeaseStatsQuery6
+- @ref isc::dhcp::LeaseMgr::startSubnetLeaseStatsQuery6
+- @ref isc::dhcp::LeaseMgr::startSubnetRangeLeaseStatsQuery6
+
+-# Iterate over the range of qualifying subnets adding a row of statistics for
+each subnet to the result-set.  Each row combines the subnet total(s) from isc::dhcp::StatsMgr
+with the type and state counts from the lease query results. For subnets with no query
+data (i.e. no leases), their rows have non-zero values for totals only.
+
+-# Finally, a CONTROL_RESULT_SUCCESS repsonse is generated containing the populated result-set.
+
+A DHCPv4 response might look like this:
+
+@code
+        {
+        "result-set\": {
+           "columns\": [
+                "subnet-id", "total-addreses",
+                "assigned-addreses", "declined-addreses"
+           ],
+           "rows\": [
+               [ 30, 256, 100, 2 ],
+               [ 40,  16, 0, 0 ],
+               [ 50, 256, 35, 0 ],
+           ],
+           timestamp\": \"2018-05-04 15:03:37.000000\" }
+        }
+@endcode
+
+and DHCPv6 response might look like this:
+
+@code
+        {
+        "result-set": {
+           "columns": [
+                "subnet-id", "total-nas", "assigned-nas",
+                "declined-nas", "total-pds", "assigned-pds"
+           ],
+           "rows": [
+               [ 30, 16, 6, 0, 65536, 400 ],
+               [ 40, 16777216, 989837, 0, 0, 0 ]
+           ],
+           "timestamp": "2018-05-04 15:03:37.000000" }
+        }
+@endcode
 
 */

src/hooks/dhcp/stat_cmds/stat_cmds.h

@@ -40,9 +40,8 @@ public:
     /// {
     ///     "command": "stat-lease4-get",
     ///     "arguments": {
-    ///         "from_storage: true/false, // optional - maybe?
+    ///         "subnet-id": x             // optional
-    ///         "subnet-id": x,            // optional
+    ///         "subnet-range": {       // optional
-    ///         "subnet-id-range": {       // optional
     ///             "first-subnet-id": x,  // id >= x
     ///             "last-subnet-id": y    // id <= x
     ///         }
@@ -84,9 +83,8 @@ public:
     /// {
     ///     "command": "stat-lease6-get",
     ///     "arguments": {
-    ///         "from_storage: true/false,
+    ///         "subnet-id": x             // optional
-    ///         "subnet-id": x,            // optional
+    ///         "subnet-range": {       // optional
-    ///         "subnet-id-range": {       // optional
     ///                 "first-subnet-id": x,   // id >= x
     ///                 "last-subnet-id": y     // id <= x
     ///         }

src/lib/dhcpsrv/lease_mgr.h

@@ -606,7 +606,7 @@ public:
     /// ordered ascending by subnet ID.
     ///
     /// @param first_subnet_id first subnet in the range of subnets
-    /// @param last last_subnet_id subnet in the range of subnets
+    /// @param last_subnet_id last subnet in the range of subnets
     /// @return A populated LeaseStatsQuery
     virtual LeaseStatsQueryPtr startSubnetRangeLeaseStatsQuery6(const SubnetID& first_subnet_id,
                                                                 const SubnetID& last_subnet_id);