[898-add-a-new-hook-to-support-bootp] Updated docs

doc/sphinx/arm/hooks.rst

@@ -441,6 +441,10 @@ loaded by the correct process per the table below.
    |                 |               |database. This library may only be used in conjuction with  |
    |                 |               |one of the supported configuration backend implementations. |
    +-----------------+---------------+------------------------------------------------------------+
+   | BOOTP           | Kea sources   |The BOOTP hooks library recognizes received BOOTP requests: |
+   |                 | (since 1.7.2) |they are translated into DHCPREQUEST packets, put into the  |
+   |                 |               |BOOTP client class and get infinite lifetime leases.        |
+   +-----------------+---------------+------------------------------------------------------------+
 
 ISC hopes to see more hooks libraries become available as time
 progresses, developed both internally and externally. Since this list
@@ -2775,6 +2779,30 @@ following:
 The ``network6-subnet-del`` command uses exactly the same syntax for
 both the command and the response.
 
+.. _bootp-library:
+
+bootp BOOTP support
+===================
+
+This library adds support for BOOTP with vendor information extensions
+(`RFC 1497 <https://tools.ietf.org/html/rfc1497>`__). Received BOOTP
+requests are recognized, translated into DHCPREQUEST packets by adding
+a dhcp-message-type option and put into the "BOOTP" client class.
+Members of this class get infinite lifetime leases but the class can
+be used too for instance to guard a pool of addresses.
+
+The library is available since Kea 1.7.2 and can be loaded in a
+similar way as other hook libraries by the ``kea-dhp4`` process.
+It takes no parameter.
+
+::
+
+    "Dhcp4": {
+        "hook_libraries": [
+            {   "library": "/usr/local/lib/libdhcp_bootp.so" },
+            ...
+        ]
+    }
 
 .. include:: hooks-class-cmds.rst
 .. include:: hooks-cb-cmds.rst