#2257: applications and services docs

docs/source/simulation_components/system/services/dns_server.rst

@@ -2,12 +2,15 @@
 
     © Crown-owned copyright 2023, Defence Science and Technology Laboratory UK
 
+.. _DNSServer:
+
 DNSServer
-=========
+#########
+
 Also known as a DNS Resolver, the ``DNSServer`` provides a DNS Server simulation by extending the base Service class.
 
 Key capabilities
-^^^^^^^^^^^^^^^^
+================
 
 - Simulates DNS requests and DNSPacket transfer across a network
 - Registers domain names and the IP Address linked to the domain name
@@ -15,12 +18,81 @@ Key capabilities
 - Leverages the Service base class for install/uninstall, status tracking, etc.
 
 Usage
-^^^^^
+=====
 - Install on a Node via the ``SoftwareManager`` to start the database service.
 - Service runs on TCP port 53 by default. (TODO: TCP for now, should be UDP in future)
 
 Implementation
-^^^^^^^^^^^^^^
+==============
 
 - DNS request and responses use a ``DNSPacket`` object
 - Extends Service class for integration with ``SoftwareManager``.
+
+Examples
+========
+
+Python
+""""""
+
+.. code-block:: python
+
+    from ipaddress import IPv4Address
+
+    from primaite.simulator.network.hardware.nodes.host.server import Server
+    from primaite.simulator.system.services.dns.dns_server import DNSServer
+
+    # Create Server
+    server = Server(
+        hostname="server",
+        ip_address="192.168.2.2",
+        subnet_mask="255.255.255.0",
+        default_gateway="192.168.1.1",
+        start_up_duration=0,
+    )
+    server.power_on()
+
+    # Install DNSServer on server
+    server.software_manager.install(DNSServer)
+    dns_server: DNSServer = server.software_manager.software.get("DNSServer")
+    dns_server.start()
+
+    # configure DatabaseService
+    dns_server.dns_register("arcd.com", IPv4Address("192.168.10.10"))
+
+
+Via Configuration
+"""""""""""""""""
+
+.. code-block:: yaml
+
+    simulation:
+        network:
+            nodes:
+                - ref: example_server
+                hostname: example_server
+                type: server
+                ...
+                services:
+                    - ref: dns_server
+                    type: DNSServer
+                    options:
+                        domain_mapping:
+                            arcd.com: 192.168.0.10
+                            another-example.com: 192.168.10.10
+
+Configuration
+=============
+
+.. include:: ../common/common_configuration.rst
+
+.. |SOFTWARE_NAME| replace:: DNSServer
+.. |SOFTWARE_NAME_BACKTICK| replace:: ``DNSServer``
+
+domain_mapping
+""""""""""""""
+
+Domain mapping takes the domain and IP Addresses as a key-value pairs i.e.
+
+If the domain is "arcd.com" and the IP Address attributed to the domain is 192.168.0.10, then the value should be ``arcd.com: 192.168.0.10``
+
+The key must be a string and the IP Address must be a valid octet i.e. in the range of ``0.0.0.0`` and ``255.255.255.255``.