feat(radius): enable dynamic client support via SQL nas table

- Activated `dynamic_clients` module to allow loading RADIUS clients dynamically from the database
- Configured SQL query to fetch client secret, shortname, and type based on Packet-Src-IP-Address
- Integrated `dynamic_clients` into the `authorize` section for real-time NAS resolution
- Eliminated need to restart FreeRADIUS when adding new NAS entries

files/mods-available/dynamic_clients

@@ -0,0 +1,41 @@
+# -*- text -*-
+#
+#  $Id: cc2bd5fd22aa473b98af5dde3fac7a66e39a9e9d $
+
+# This module loads RADIUS clients as needed, rather than when the server
+# starts.
+#
+#  There are no configuration entries for this module.  Instead, it
+#  relies on the "client" configuration.  You must:
+#
+#       1) link raddb/sites-enabled/dynamic_clients to
+#          raddb/sites-available/dynamic_clients
+#
+#       2) Define a client network/mask (see top of the above file)
+#
+#       3) uncomment the "directory" entry in that client definition
+#
+#       4) list "dynamic_clients" in the "authorize" section of the
+#          "dynamic_clients' virtual server.  The default example already
+#          does this.
+#
+#       5) put files into the above directory, one per IP.
+#          e.g. file "192.0.2.1" should contain a normal client definition
+#          for a client with IP address 192.0.2.1.
+#
+#  For more documentation, see the file:
+#
+#       raddb/sites-available/dynamic-clients
+#
+dynamic_clients {
+    sql = "SELECT secret, shortname, type FROM nas WHERE nasname = '%{Packet-Src-IP-Address}'"
+
+    key = "%{Packet-Src-IP-Address}"
+
+    client {
+        ipaddr = "%{Packet-Src-IP-Address}"
+        secret = "%{reply:secret}"
+        shortname = "%{reply:shortname}"
+        nastype = "%{reply:type}"
+    }
+}