#1752 - Created dns.py protocol file with DNSPacket and DNSRequest and DNSReply packets

- Added reset_component logic for dns_server.py and dns_client.py

src/primaite/simulator/network/protocols/dns.py

@@ -0,0 +1,113 @@
+from __future__ import annotations
+
+from ipaddress import IPv4Address
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class DNSEntry(BaseModel):
+    """
+    Represents an entry in the DNS cache.
+
+    :param domain_name: The domain name which a node would like to access.
+    :param ip_address: The IP address through which the domain name is reachable.
+    """
+
+    domain_name: str
+    ip_address: IPv4Address
+
+
+class DNSRequest(BaseModel):
+    """Represents a DNS Request packet of a network frame.
+
+    :param sender_mac_addr: Sender MAC address.
+    :param sender_ip: Sender IP address.
+    :param target_mac_addr: Target MAC address.
+    :param target_ip: Target IP address.
+    :param domain_name_request: Domain Name Request for IP address.
+    """
+
+    sender_mac_addr: str
+    "Sender MAC address."
+    sender_ip: IPv4Address
+    "Sender IP address."
+    target_mac_addr: Optional[str] = None
+    "Target MAC address of the DNS Server."
+    target_ip: IPv4Address
+    "Target IP address of the DNS Server."
+    domain_name_request: str
+    "Domain Name Request for IP address."
+
+
+class DNSReply(BaseModel):
+    """Represents a DNS Reply packet of a network frame.
+
+    :param sender_mac_addr: Sender MAC address.
+    :param sender_ip: Sender IP address.
+    :param target_mac_addr: Target MAC address of DNS Client.
+    :param target_ip: Target IP address of DNS Client.
+    :param domain_name_ip_address: IP Address of the Domain Name requested.
+    """
+
+    sender_mac_addr: str
+    "Sender MAC address."
+    sender_ip: IPv4Address
+    "Sender IP address."
+    target_mac_addr: Optional[str] = None
+    "Target MAC address of the DNS Server."
+    target_ip: IPv4Address
+    "Target IP address of the DNS Server."
+    domain_name_ip_address: IPv4Address
+    "IP Address of the Domain Name requested."
+
+
+class DNSPacket(BaseModel):
+    """
+    Represents the DNS layer of a network frame.
+
+    :param dns_request: DNS Request packet sent by DNS Client.
+    :param dns_reply: DNS Reply packet generated by DNS Server.
+
+    :Example:
+
+    >>> dns_request = DNSPacket(
+    ...     dns_request=DNSRequest(sender_mac_addr="aa:bb:cc:dd:ee:ff", sender_ip = IPv4Address("192.168.0.1"),
+    ...            target_ip = IPv4Address("192.168.0.2"), domain_name_request="www.google.co.uk"),
+    ...     dns_reply=None
+    ... )
+    >>> dns_response = DNSPacket(
+    ...     dns_request=DNSRequest(sender_mac_addr="aa:bb:cc:dd:ee:ff", sender_ip = IPv4Address("192.168.0.1"),
+    ...            target_ip = IPv4Address("192.168.0.2"), domain_name_request="www.google.co.uk"),
+    ...     dns_reply=DNSReply(sender_mac_addr="gg:hh:ii:jj:kk:ll", sender_ip = IPv4Address("192.168.0.2"),
+    ...            target_ip = IPv4Address("192.168.0.1"), domain_name_ip_address=IPv4Address("142.250.179.227"))
+    ... )
+    """
+
+    dns_request: DNSRequest
+    "DNS Request packet sent by DNS Client."
+    dns_reply: Optional[DNSReply] = None
+    "DNS Reply packet generated by DNS Server."
+
+    def generate_reply(self, domain_ip_address: IPv4Address) -> DNSPacket:
+        """Generate a new DNSPacket to be sent as a response with a DNS Reply packet which contains the IP address.
+
+        :param domain_ip_address: The IP address that was being sought after from the original target domain name.
+        :return: A new instance of DNSPacket.
+        """
+        return DNSPacket(
+            dns_request=DNSRequest(
+                sender_mac_addr=self.dns_request.sender_mac_addr,
+                sender_ip=self.dns_request.sender_ip,
+                target_mac_addr=self.dns_request.target_mac_addr,
+                target_ip=self.dns_request.target_ip,
+                domain_name_request=self.dns_request.domain_name_request,
+            ),
+            dns_reply=DNSReply(
+                sender_mac_addr=self.dns_request.target_mac_addr,
+                sender_ip=self.dns_request.target_ip,
+                target_mac_addr=self.dns_request.sender_mac_addr,
+                target_ip=self.dns_request.sender_ip,
+                domain_name_ip_address=domain_ip_address,
+            ),
+        )

src/primaite/simulator/system/services/dns_client.py

@@ -41,7 +41,8 @@ class DNSClient(BaseModel):
         This method ensures the Service is ready for a new episode, including resetting any
         stateful properties or statistics, and clearing any message queues.
         """
-        pass
+        self.target_url = ""
+        self.dns_cache = {}
 
     def send(self, payload: Any, session_id: str, **kwargs) -> bool:
         """

src/primaite/simulator/system/services/dns_server.py

@@ -7,7 +7,7 @@ from pydantic import BaseModel
 class DNSServer(BaseModel):
     """Represents a DNS Server as a Service."""
 
-    dns_table: dict[str:str] = {"https://google.co.uk": "8.8.8.8"}
+    dns_table: dict[str:str] = {}
 
     @abstractmethod
     def describe_state(self) -> Dict:
@@ -37,7 +37,7 @@ class DNSServer(BaseModel):
         This method ensures the Service is ready for a new episode, including resetting any
         stateful properties or statistics, and clearing any message queues.
         """
-        pass
+        self.dns_table = {}
 
     def send(self, payload: Any, session_id: str, **kwargs) -> bool:
         """