#1752: simplifying the DNS implementation - switch to TCP + fixing the DNS integration test

src/primaite/simulator/network/hardware/base.py

@@ -406,7 +406,8 @@ class SwitchPort(SimComponent):
         if self.enabled:
             frame.decrement_ttl()
             self.pcap.capture(frame)
-            self.connected_node.forward_frame(frame=frame, incoming_port=self)
+            connected_node: Node = self.connected_node
+            connected_node.forward_frame(frame=frame, incoming_port=self)
             return True
         return False
 

src/primaite/simulator/network/networks.py

@@ -132,6 +132,8 @@ def arcd_uc2_network() -> Network:
     )
     client_1.power_on()
     client_1.software_manager.install(DNSClient)
+    client_1_dns_client_service: DNSServer = client_1.software_manager.software["DNSClient"]  # noqa
+    client_1_dns_client_service.start()
     network.connect(endpoint_b=client_1.ethernet_port[1], endpoint_a=switch_2.switch_ports[1])
     client_1.software_manager.install(DataManipulationBot)
     db_manipulation_bot: DataManipulationBot = client_1.software_manager.software["DataManipulationBot"]
@@ -143,6 +145,8 @@ def arcd_uc2_network() -> Network:
     )
     client_2.power_on()
     client_2.software_manager.install(DNSClient)
+    client_2_dns_client_service: DNSServer = client_2.software_manager.software["DNSClient"]  # noqa
+    client_2_dns_client_service.start()
     network.connect(endpoint_b=client_2.ethernet_port[1], endpoint_a=switch_2.switch_ports[2])
 
     # Domain Controller
@@ -215,6 +219,7 @@ def arcd_uc2_network() -> Network:
 
     # register the web_server to a domain
     dns_server_service: DNSServer = domain_controller.software_manager.software["DNSServer"]  # noqa
+    dns_server_service.start()
     dns_server_service.dns_register("arcd.com", web_server.ip_address)
 
     # Backup Server

src/primaite/simulator/network/transmission/data_link_layer.py

@@ -5,7 +5,6 @@ from pydantic import BaseModel
 
 from primaite import getLogger
 from primaite.simulator.network.protocols.arp import ARPPacket
-from primaite.simulator.network.protocols.dns import DNSPacket
 from primaite.simulator.network.transmission.network_layer import ICMPPacket, IPPacket, IPProtocol
 from primaite.simulator.network.transmission.primaite_layer import PrimaiteHeader
 from primaite.simulator.network.transmission.transport_layer import TCPHeader, UDPHeader
@@ -97,8 +96,6 @@ class Frame(BaseModel):
     "ICMP header."
     arp: Optional[ARPPacket] = None
     "ARP packet."
-    dns: Optional[DNSPacket] = None
-    "DNS packet."
     primaite: PrimaiteHeader
     "PrimAITE header."
     payload: Optional[Any] = None

src/primaite/simulator/system/core/session_manager.py

@@ -74,7 +74,9 @@ class SessionManager:
     """
 
     def __init__(self, sys_log: SysLog, arp_cache: "ARPCache"):
-        self.sessions_by_key: Dict[Tuple[IPProtocol, IPv4Address, Optional[Port], Optional[Port]], Session] = {}
+        self.sessions_by_key: Dict[
+            Tuple[IPProtocol, IPv4Address, IPv4Address, Optional[Port], Optional[Port]], Session
+        ] = {}
         self.sessions_by_uuid: Dict[str, Session] = {}
         self.sys_log: SysLog = sys_log
         self.software_manager: SoftwareManager = None  # Noqa
@@ -94,7 +96,7 @@ class SessionManager:
     @staticmethod
     def _get_session_key(
         frame: Frame, inbound_frame: bool = True
-    ) -> Tuple[IPProtocol, IPv4Address, IPv4Address, Optional[Port], Optional[Port]]:
+    ) -> Tuple[IPProtocol, IPv4Address, Optional[Port], Optional[Port]]:
         """
         Extracts the session key from the given frame.
 

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

@@ -22,7 +22,8 @@ class DNSClient(Service):
         kwargs["port"] = Port.DNS
         # DNS uses UDP by default
         # it switches to TCP when the bytes exceed 512 (or 4096) bytes
-        kwargs["protocol"] = IPProtocol.UDP
+        # TCP for now
+        kwargs["protocol"] = IPProtocol.TCP
         super().__init__(**kwargs)
 
     def describe_state(self) -> Dict:
@@ -84,14 +85,15 @@ class DNSClient(Service):
                 return False
             else:
                 # send a request to check if domain name exists in the DNS Server
-                self.software_manager.send_payload_to_session_manager(
+                software_manager: SoftwareManager = self.software_manager
+                software_manager.send_payload_to_session_manager(
                     payload=payload,
                     dest_ip_address=dest_ip_address,
                     dest_port=dest_port,
                 )
 
                 # check if the domain has been added to cache
-                if self.dns_cache.get(target_domain) is None:
+                if self.dns_cache.get(target_domain, None) is None:
                     # call function again
                     return self.check_domain_exists(
                         target_domain=target_domain,

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

@@ -23,7 +23,8 @@ class DNSServer(Service):
         kwargs["port"] = Port.DNS
         # DNS uses UDP by default
         # it switches to TCP when the bytes exceed 512 (or 4096) bytes
-        kwargs["protocol"] = IPProtocol.UDP
+        # TCP for now
+        kwargs["protocol"] = IPProtocol.TCP
         super().__init__(**kwargs)
 
     def describe_state(self) -> Dict:

tests/integration_tests/system/test_dns_client_server.py

@@ -4,6 +4,7 @@ from primaite.simulator.network.hardware.nodes.computer import Computer
 from primaite.simulator.network.hardware.nodes.server import Server
 from primaite.simulator.system.services.dns_client import DNSClient
 from primaite.simulator.system.services.dns_server import DNSServer
+from primaite.simulator.system.services.service import ServiceOperatingState
 
 
 def test_dns_client_server(uc2_network):
@@ -13,12 +14,17 @@ def test_dns_client_server(uc2_network):
     dns_client: DNSClient = client_1.software_manager.software["DNSClient"]
     dns_server: DNSServer = domain_controller.software_manager.software["DNSServer"]
 
-    # register a domain to web server
+    assert dns_client.operating_state == ServiceOperatingState.RUNNING
-    dns_server.dns_register("real-domain.com", IPv4Address("192.168.1.12"))
+    assert dns_server.operating_state == ServiceOperatingState.RUNNING
 
     dns_server.show()
 
-    dns_client.check_domain_exists(target_domain="real-domain.com", dest_ip_address=IPv4Address("192.168.1.14"))
+    # fake domain should not be added to dns cache
+    dns_client.check_domain_exists(
+        target_domain="fake-domain.com", dest_ip_address=IPv4Address(domain_controller.ip_address)
+    )
+    assert dns_client.dns_cache.get("fake-domain.com", None) is None
 
-    # should register the domain in the client cache
+    # arcd.com is registered in dns server and should be saved to cache
-    assert dns_client.dns_cache.get("real-domain.com") is not None
+    dns_client.check_domain_exists(target_domain="arcd.com", dest_ip_address=IPv4Address(domain_controller.ip_address))
+    assert dns_client.dns_cache.get("arcd.com", None) is not None

tests/unit_tests/_primaite/_simulator/_system/_services/test_dns.py

@@ -31,7 +31,7 @@ def test_create_dns_server(dns_server):
     dns_server_service: DNSServer = dns_server.software_manager.software["DNSServer"]
     assert dns_server_service.name is "DNSServer"
     assert dns_server_service.port is Port.DNS
-    assert dns_server_service.protocol is IPProtocol.UDP
+    assert dns_server_service.protocol is IPProtocol.TCP
 
 
 def test_create_dns_client(dns_client):
@@ -39,7 +39,7 @@ def test_create_dns_client(dns_client):
     dns_client_service: DNSClient = dns_client.software_manager.software["DNSClient"]
     assert dns_client_service.name is "DNSClient"
     assert dns_client_service.port is Port.DNS
-    assert dns_client_service.protocol is IPProtocol.UDP
+    assert dns_client_service.protocol is IPProtocol.TCP
 
 
 def test_dns_server_domain_name_registration(dns_server):