Merge branch 'dev' into feature/2041_2042-Add-NTP-Services

src/primaite/simulator/system/applications/database_client.py

@@ -5,7 +5,7 @@ from uuid import uuid4
 from primaite import getLogger
 from primaite.simulator.network.transmission.network_layer import IPProtocol
 from primaite.simulator.network.transmission.transport_layer import Port
-from primaite.simulator.system.applications.application import Application, ApplicationOperatingState
+from primaite.simulator.system.applications.application import Application
 from primaite.simulator.system.core.software_manager import SoftwareManager
 
 _LOGGER = getLogger(__name__)
@@ -23,7 +23,6 @@ class DatabaseClient(Application):
 
     server_ip_address: Optional[IPv4Address] = None
     server_password: Optional[str] = None
-    connected: bool = False
     _query_success_tracker: Dict[str, bool] = {}
 
     def __init__(self, **kwargs):
@@ -66,18 +65,24 @@ class DatabaseClient(Application):
         self.server_password = server_password
         self.sys_log.info(f"{self.name}: Configured the {self.name} with {server_ip_address=}, {server_password=}.")
 
-    def connect(self) -> bool:
+    def connect(self, connection_id: Optional[str] = None) -> bool:
         """Connect to a Database Service."""
         if not self._can_perform_action():
             return False
 
-        if not self.connected:
-            return self._connect(self.server_ip_address, self.server_password)
-        # already connected
-        return True
+        if not connection_id:
+            connection_id = str(uuid4())
+
+        return self._connect(
+            server_ip_address=self.server_ip_address, password=self.server_password, connection_id=connection_id
+        )
 
     def _connect(
-        self, server_ip_address: IPv4Address, password: Optional[str] = None, is_reattempt: bool = False
+        self,
+        server_ip_address: IPv4Address,
+        connection_id: Optional[str] = None,
+        password: Optional[str] = None,
+        is_reattempt: bool = False,
     ) -> bool:
         """
         Connects the DatabaseClient to the DatabaseServer.
@@ -92,33 +97,58 @@ class DatabaseClient(Application):
         :type: is_reattempt: Optional[bool]
         """
         if is_reattempt:
-            if self.connected:
-                self.sys_log.info(f"{self.name}: DatabaseClient connection to {server_ip_address} authorised")
+            if self.connections.get(connection_id):
+                self.sys_log.info(
+                    f"{self.name} {connection_id=}: DatabaseClient connection to {server_ip_address} authorised"
+                )
                 self.server_ip_address = server_ip_address
-                return self.connected
+                return True
             else:
-                self.sys_log.info(f"{self.name}: DatabaseClient connection to {server_ip_address} declined")
+                self.sys_log.info(
+                    f"{self.name} {connection_id=}: DatabaseClient connection to {server_ip_address} declined"
+                )
                 return False
-        payload = {"type": "connect_request", "password": password}
+        payload = {
+            "type": "connect_request",
+            "password": password,
+            "connection_id": connection_id,
+        }
         software_manager: SoftwareManager = self.software_manager
         software_manager.send_payload_to_session_manager(
             payload=payload, dest_ip_address=server_ip_address, dest_port=self.port
         )
-        return self._connect(server_ip_address, password, True)
+        return self._connect(
+            server_ip_address=server_ip_address, password=password, connection_id=connection_id, is_reattempt=True
+        )
 
-    def disconnect(self):
+    def disconnect(self, connection_id: Optional[str] = None) -> bool:
         """Disconnect from the Database Service."""
-        if self.connected and self.operating_state is ApplicationOperatingState.RUNNING:
-            software_manager: SoftwareManager = self.software_manager
-            software_manager.send_payload_to_session_manager(
-                payload={"type": "disconnect"}, dest_ip_address=self.server_ip_address, dest_port=self.port
-            )
+        if not self._can_perform_action():
+            self.sys_log.error(f"Unable to disconnect - {self.name} is {self.operating_state.name}")
+            return False
 
-            self.sys_log.info(f"{self.name}: DatabaseClient disconnected from {self.server_ip_address}")
-            self.server_ip_address = None
-            self.connected = False
+        # if there are no connections - nothing to disconnect
+        if not len(self.connections):
+            self.sys_log.error(f"Unable to disconnect - {self.name} has no active connections.")
+            return False
 
-    def _query(self, sql: str, query_id: str, is_reattempt: bool = False) -> bool:
+        # if no connection provided, disconnect the first connection
+        if not connection_id:
+            connection_id = list(self.connections.keys())[0]
+
+        software_manager: SoftwareManager = self.software_manager
+        software_manager.send_payload_to_session_manager(
+            payload={"type": "disconnect", "connection_id": connection_id},
+            dest_ip_address=self.server_ip_address,
+            dest_port=self.port,
+        )
+        self.remove_connection(connection_id=connection_id)
+
+        self.sys_log.info(
+            f"{self.name}: DatabaseClient disconnected connection {connection_id} from {self.server_ip_address}"
+        )
+
+    def _query(self, sql: str, query_id: str, connection_id: str, is_reattempt: bool = False) -> bool:
         """
         Send a query to the connected database server.
 
@@ -141,19 +171,17 @@ class DatabaseClient(Application):
         else:
             software_manager: SoftwareManager = self.software_manager
             software_manager.send_payload_to_session_manager(
-                payload={"type": "sql", "sql": sql, "uuid": query_id},
+                payload={"type": "sql", "sql": sql, "uuid": query_id, "connection_id": connection_id},
                 dest_ip_address=self.server_ip_address,
                 dest_port=self.port,
             )
-            return self._query(sql=sql, query_id=query_id, is_reattempt=True)
+            return self._query(sql=sql, query_id=query_id, connection_id=connection_id, is_reattempt=True)
 
     def run(self) -> None:
         """Run the DatabaseClient."""
         super().run()
-        if self.operating_state == ApplicationOperatingState.RUNNING:
-            self.connect()
 
-    def query(self, sql: str, is_reattempt: bool = False) -> bool:
+    def query(self, sql: str, connection_id: Optional[str] = None) -> bool:
         """
         Send a query to the Database Service.
 
@@ -164,20 +192,17 @@ class DatabaseClient(Application):
         if not self._can_perform_action():
             return False
 
-        if self.connected:
-            query_id = str(uuid4())
+        if connection_id is None:
+            connection_id = str(uuid4())
+
+        if not self.connections.get(connection_id):
+            if not self.connect(connection_id=connection_id):
+                return False
 
             # Initialise the tracker of this ID to False
-            self._query_success_tracker[query_id] = False
-            return self._query(sql=sql, query_id=query_id)
-        else:
-            if is_reattempt:
-                return False
-
-            if not self.connect():
-                return False
-
-            self.query(sql=sql, is_reattempt=True)
+        uuid = str(uuid4())
+        self._query_success_tracker[uuid] = False
+        return self._query(sql=sql, query_id=uuid, connection_id=connection_id)
 
     def receive(self, payload: Any, session_id: str, **kwargs) -> bool:
         """
@@ -192,13 +217,13 @@ class DatabaseClient(Application):
 
         if isinstance(payload, dict) and payload.get("type"):
             if payload["type"] == "connect_response":
-                self.connected = payload["response"] == True
+                if payload["response"] is True:
+                    # add connection
+                    self.add_connection(connection_id=payload.get("connection_id"), session_id=session_id)
             elif payload["type"] == "sql":
                 query_id = payload.get("uuid")
                 status_code = payload.get("status_code")
                 self._query_success_tracker[query_id] = status_code == 200
                 if self._query_success_tracker[query_id]:
                     _LOGGER.debug(f"Received payload {payload}")
-                else:
-                    self.connected = False
         return True

src/primaite/simulator/system/applications/red_applications/data_manipulation_bot.py

@@ -5,7 +5,6 @@ from typing import Optional
 from primaite import getLogger
 from primaite.game.science import simulate_trial
 from primaite.simulator.core import RequestManager, RequestType
-from primaite.simulator.system.applications.application import ApplicationOperatingState
 from primaite.simulator.system.applications.database_client import DatabaseClient
 
 _LOGGER = getLogger(__name__)
@@ -149,9 +148,9 @@ class DataManipulationBot(DatabaseClient):
             if simulate_trial(p_of_success):
                 self.sys_log.info(f"{self.name}: Performing data manipulation")
                 # perform the attack
-                if not self.connected:
+                if not len(self.connections):
                     self.connect()
-                if self.connected:
+                if len(self.connections):
                     self.query(self.payload)
                     self.sys_log.info(f"{self.name} payload delivered: {self.payload}")
                     attack_successful = True
@@ -177,9 +176,9 @@ class DataManipulationBot(DatabaseClient):
 
         This is the core loop where the bot sequentially goes through the stages of the attack.
         """
-        if self.operating_state != ApplicationOperatingState.RUNNING:
+        if not self._can_perform_action():
             return
-        if self.server_ip_address and self.payload and self.operating_state:
+        if self.server_ip_address and self.payload:
             self.sys_log.info(f"{self.name}: Running")
             self._logon()
             self._perform_port_scan(p_of_success=self.port_scan_p_of_success)

src/primaite/simulator/system/applications/red_applications/dos_bot.py

@@ -0,0 +1,192 @@
+from enum import IntEnum
+from ipaddress import IPv4Address
+from typing import Optional
+
+from primaite import getLogger
+from primaite.game.science import simulate_trial
+from primaite.simulator.core import RequestManager, RequestType
+from primaite.simulator.network.transmission.transport_layer import Port
+from primaite.simulator.system.applications.application import Application
+from primaite.simulator.system.applications.database_client import DatabaseClient
+
+_LOGGER = getLogger(__name__)
+
+
+class DoSAttackStage(IntEnum):
+    """Enum representing the different stages of a Denial of Service attack."""
+
+    NOT_STARTED = 0
+    "Attack not yet started."
+
+    PORT_SCAN = 1
+    "Attack is in discovery stage - checking if provided ip and port are open."
+
+    ATTACKING = 2
+    "Denial of Service attack is in progress."
+
+    COMPLETED = 3
+    "Attack is completed."
+
+
+class DoSBot(DatabaseClient, Application):
+    """A bot that simulates a Denial of Service attack."""
+
+    target_ip_address: Optional[IPv4Address] = None
+    """IP address of the target service."""
+
+    target_port: Optional[Port] = None
+    """Port of the target service."""
+
+    payload: Optional[str] = None
+    """Payload to deliver to the target service as part of the denial of service attack."""
+
+    repeat: bool = False
+    """If true, the Denial of Service bot will keep performing the attack."""
+
+    attack_stage: DoSAttackStage = DoSAttackStage.NOT_STARTED
+    """Current stage of the DoS kill chain."""
+
+    port_scan_p_of_success: float = 0.1
+    """Probability of port scanning being sucessful."""
+
+    dos_intensity: float = 1.0
+    """How much of the max sessions will be used by the DoS when attacking."""
+
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        self.name = "DoSBot"
+        self.max_sessions = 1000  # override normal max sessions
+
+    def set_original_state(self):
+        """Set the original state of the Denial of Service Bot."""
+        _LOGGER.debug(f"Setting {self.name} original state on node {self.software_manager.node.hostname}")
+        super().set_original_state()
+        vals_to_include = {
+            "target_ip_address",
+            "target_port",
+            "payload",
+            "repeat",
+            "attack_stage",
+            "max_sessions",
+            "port_scan_p_of_success",
+            "dos_intensity",
+        }
+        self._original_state.update(self.model_dump(include=vals_to_include))
+
+    def reset_component_for_episode(self, episode: int):
+        """Reset the original state of the SimComponent."""
+        _LOGGER.debug(f"Resetting {self.name} state on node {self.software_manager.node.hostname}")
+        super().reset_component_for_episode(episode)
+
+    def _init_request_manager(self) -> RequestManager:
+        rm = super()._init_request_manager()
+
+        rm.add_request(name="execute", request_type=RequestType(func=lambda request, context: self.run()))
+
+        return rm
+
+    def configure(
+        self,
+        target_ip_address: IPv4Address,
+        target_port: Optional[Port] = Port.POSTGRES_SERVER,
+        payload: Optional[str] = None,
+        repeat: bool = False,
+        port_scan_p_of_success: float = 0.1,
+        dos_intensity: float = 1.0,
+        max_sessions: int = 1000,
+    ):
+        """
+        Configure the Denial of Service bot.
+
+        :param: target_ip_address: The IP address of the Node containing the target service.
+        :param: target_port: The port of the target service. Optional - Default is `Port.HTTP`
+        :param: payload: The payload the DoS Bot will throw at the target service. Optional - Default is `None`
+        :param: repeat: If True, the bot will maintain the attack. Optional - Default is `True`
+        :param: port_scan_p_of_success: The chance of the port scan being sucessful. Optional - Default is 0.1 (10%)
+        :param: dos_intensity: The intensity of the DoS attack.
+            Multiplied with the application's max session - Default is 1.0
+        :param: max_sessions: The maximum number of sessions the DoS bot will attack with. Optional - Default is 1000
+        """
+        self.target_ip_address = target_ip_address
+        self.target_port = target_port
+        self.payload = payload
+        self.repeat = repeat
+        self.port_scan_p_of_success = port_scan_p_of_success
+        self.dos_intensity = dos_intensity
+        self.max_sessions = max_sessions
+        self.sys_log.info(
+            f"{self.name}: Configured the {self.name} with {target_ip_address=}, {target_port=}, {payload=}, "
+            f"{repeat=}, {port_scan_p_of_success=}, {dos_intensity=}, {max_sessions=}."
+        )
+
+    def run(self):
+        """Run the Denial of Service Bot."""
+        super().run()
+        self._application_loop()
+
+    def _application_loop(self):
+        """
+        The main application loop for the Denial of Service bot.
+
+        The loop goes through the stages of a DoS attack.
+        """
+        if not self._can_perform_action():
+            return
+
+        # DoS bot cannot do anything without a target
+        if not self.target_ip_address or not self.target_port:
+            self.sys_log.error(
+                f"{self.name} is not properly configured. {self.target_ip_address=}, {self.target_port=}"
+            )
+            return
+
+        self.clear_connections()
+        self._perform_port_scan(p_of_success=self.port_scan_p_of_success)
+        self._perform_dos()
+
+        if self.repeat and self.attack_stage is DoSAttackStage.ATTACKING:
+            self.attack_stage = DoSAttackStage.NOT_STARTED
+        else:
+            self.attack_stage = DoSAttackStage.COMPLETED
+
+    def _perform_port_scan(self, p_of_success: Optional[float] = 0.1):
+        """
+        Perform a simulated port scan to check for open SQL ports.
+
+        Advances the attack stage to `PORT_SCAN` if successful.
+
+        :param p_of_success: Probability of successful port scan, by default 0.1.
+        """
+        if self.attack_stage == DoSAttackStage.NOT_STARTED:
+            # perform a port scan to identify that the SQL port is open on the server
+            if simulate_trial(p_of_success):
+                self.sys_log.info(f"{self.name}: Performing port scan")
+                # perform the port scan
+                port_is_open = True  # Temporary; later we can implement NMAP port scan.
+                if port_is_open:
+                    self.sys_log.info(f"{self.name}: ")
+                    self.attack_stage = DoSAttackStage.PORT_SCAN
+
+    def _perform_dos(self):
+        """
+        Perform the Denial of Service attack.
+
+        DoSBot does this by clogging up the available connections to a service.
+        """
+        if not self.attack_stage == DoSAttackStage.PORT_SCAN:
+            return
+        self.attack_stage = DoSAttackStage.ATTACKING
+        self.server_ip_address = self.target_ip_address
+        self.port = self.target_port
+
+        dos_sessions = int(float(self.max_sessions) * self.dos_intensity)
+        for i in range(dos_sessions):
+            self.connect()
+
+    def apply_timestep(self, timestep: int) -> None:
+        """
+        Apply a timestep to the bot, iterate through the application loop.
+
+        :param timestep: The timestep value to update the bot's state.
+        """
+        self._application_loop()

src/primaite/simulator/system/services/database/database_service.py

@@ -1,4 +1,3 @@
-from datetime import datetime
 from ipaddress import IPv4Address
 from typing import Any, Dict, List, Literal, Optional, Union
 
@@ -22,7 +21,6 @@ class DatabaseService(Service):
     """
 
     password: Optional[str] = None
-    connections: Dict[str, datetime] = {}
 
     backup_server: IPv4Address = None
     """IP address of the backup server."""
@@ -47,7 +45,7 @@ class DatabaseService(Service):
         super().set_original_state()
         vals_to_include = {
             "password",
-            "connections",
+            "_connections",
             "backup_server",
             "latest_backup_directory",
             "latest_backup_file_name",
@@ -57,7 +55,7 @@ class DatabaseService(Service):
     def reset_component_for_episode(self, episode: int):
         """Reset the original state of the SimComponent."""
         _LOGGER.debug("Resetting DatabaseService original state on node {self.software_manager.node.hostname}")
-        self.connections.clear()
+        self.clear_connections()
         super().reset_component_for_episode(episode)
 
     def configure_backup(self, backup_server: IPv4Address):
@@ -140,24 +138,39 @@ class DatabaseService(Service):
         self.folder = self.file_system.get_folder_by_id(self._db_file.folder_id)
 
     def _process_connect(
-        self, session_id: str, password: Optional[str] = None
+        self, connection_id: str, password: Optional[str] = None
     ) -> Dict[str, Union[int, Dict[str, bool]]]:
         status_code = 500  # Default internal server error
         if self.operating_state == ServiceOperatingState.RUNNING:
             status_code = 503  # service unavailable
+            if self.health_state_actual == SoftwareHealthState.OVERWHELMED:
+                self.sys_log.error(
+                    f"{self.name}: Connect request for {connection_id=} declined. Service is at capacity."
+                )
             if self.health_state_actual == SoftwareHealthState.GOOD:
                 if self.password == password:
                     status_code = 200  # ok
-                    self.connections[session_id] = datetime.now()
-                    self.sys_log.info(f"{self.name}: Connect request for {session_id=} authorised")
+                    # try to create connection
+                    if not self.add_connection(connection_id=connection_id):
+                        status_code = 500
+                        self.sys_log.info(f"{self.name}: Connect request for {connection_id=} declined")
+                    else:
+                        self.sys_log.info(f"{self.name}: Connect request for {connection_id=} authorised")
                 else:
                     status_code = 401  # Unauthorised
-                    self.sys_log.info(f"{self.name}: Connect request for {session_id=} declined")
+                    self.sys_log.info(f"{self.name}: Connect request for {connection_id=} declined")
         else:
             status_code = 404  # service not found
-        return {"status_code": status_code, "type": "connect_response", "response": status_code == 200}
+        return {
+            "status_code": status_code,
+            "type": "connect_response",
+            "response": status_code == 200,
+            "connection_id": connection_id,
+        }
 
-    def _process_sql(self, query: Literal["SELECT", "DELETE"], query_id: str) -> Dict[str, Union[int, List[Any]]]:
+    def _process_sql(
+        self, query: Literal["SELECT", "DELETE"], query_id: str, connection_id: Optional[str] = None
+    ) -> Dict[str, Union[int, List[Any]]]:
         """
         Executes the given SQL query and returns the result.
 
@@ -169,15 +182,28 @@ class DatabaseService(Service):
         :return: Dictionary containing status code and data fetched.
         """
         self.sys_log.info(f"{self.name}: Running {query}")
+
         if query == "SELECT":
             if self.health_state_actual == SoftwareHealthState.GOOD:
-                return {"status_code": 200, "type": "sql", "data": True, "uuid": query_id}
+                return {
+                    "status_code": 200,
+                    "type": "sql",
+                    "data": True,
+                    "uuid": query_id,
+                    "connection_id": connection_id,
+                }
             else:
                 return {"status_code": 404, "data": False}
         elif query == "DELETE":
             if self.health_state_actual == SoftwareHealthState.GOOD:
                 self.health_state_actual = SoftwareHealthState.COMPROMISED
-                return {"status_code": 200, "type": "sql", "data": False, "uuid": query_id}
+                return {
+                    "status_code": 200,
+                    "type": "sql",
+                    "data": False,
+                    "uuid": query_id,
+                    "connection_id": connection_id,
+                }
             else:
                 return {"status_code": 404, "data": False}
         else:
@@ -203,19 +229,25 @@ class DatabaseService(Service):
         :param session_id: The session identifier.
         :return: True if the Status Code is 200, otherwise False.
         """
-        if not super().receive(payload=payload, session_id=session_id, **kwargs):
+        result = {"status_code": 500, "data": []}
+
+        # if server service is down, return error
+        if not self._can_perform_action():
             return False
 
-        result = {"status_code": 500, "data": []}
         if isinstance(payload, dict) and payload.get("type"):
             if payload["type"] == "connect_request":
-                result = self._process_connect(session_id=session_id, password=payload.get("password"))
+                result = self._process_connect(
+                    connection_id=payload.get("connection_id"), password=payload.get("password")
+                )
             elif payload["type"] == "disconnect":
-                if session_id in self.connections:
-                    self.connections.pop(session_id)
+                if payload["connection_id"] in self.connections:
+                    self.remove_connection(connection_id=payload["connection_id"])
             elif payload["type"] == "sql":
-                if session_id in self.connections:
-                    result = self._process_sql(query=payload["sql"], query_id=payload["uuid"])
+                if payload.get("connection_id") in self.connections:
+                    result = self._process_sql(
+                        query=payload["sql"], query_id=payload["uuid"], connection_id=payload["connection_id"]
+                    )
                 else:
                     result = {"status_code": 401, "type": "sql"}
         self.send(payload=result, session_id=session_id)

src/primaite/simulator/system/services/ftp/ftp_client.py

@@ -20,9 +20,6 @@ class FTPClient(FTPServiceABC):
     RFC 959: https://datatracker.ietf.org/doc/html/rfc959
     """
 
-    connected: bool = False
-    """Keeps track of whether or not the FTP client is connected to an FTP server."""
-
     def __init__(self, **kwargs):
         kwargs["name"] = "FTPClient"
         kwargs["port"] = Port.FTP
@@ -129,10 +126,7 @@ class FTPClient(FTPServiceABC):
         software_manager.send_payload_to_session_manager(
             payload=payload, dest_ip_address=dest_ip_address, dest_port=dest_port
         )
-        if payload.status_code == FTPStatusCode.OK:
-            self.connected = False
-            return True
-        return False
+        return payload.status_code == FTPStatusCode.OK
 
     def send_file(
         self,
@@ -179,9 +173,9 @@ class FTPClient(FTPServiceABC):
             return False
 
         # check if FTP is currently connected to IP
-        self.connected = self._connect_to_server(dest_ip_address=dest_ip_address, dest_port=dest_port)
+        self._connect_to_server(dest_ip_address=dest_ip_address, dest_port=dest_port)
 
-        if not self.connected:
+        if not len(self.connections):
             return False
         else:
             self.sys_log.info(f"Sending file {src_folder_name}/{src_file_name} to {str(dest_ip_address)}")
@@ -230,9 +224,9 @@ class FTPClient(FTPServiceABC):
         :type: dest_port: Optional[Port]
         """
         # check if FTP is currently connected to IP
-        self.connected = self._connect_to_server(dest_ip_address=dest_ip_address, dest_port=dest_port)
+        self._connect_to_server(dest_ip_address=dest_ip_address, dest_port=dest_port)
 
-        if not self.connected:
+        if not len(self.connections):
             return False
         else:
             # send retrieve request
@@ -286,6 +280,14 @@ class FTPClient(FTPServiceABC):
             self.sys_log.error(f"FTP Server could not be found - Error Code: {FTPStatusCode.NOT_FOUND.value}")
             return False
 
+        # if PORT succeeded, add the connection as an active connection list
+        if payload.ftp_command is FTPCommand.PORT and payload.status_code is FTPStatusCode.OK:
+            self.add_connection(connection_id=session_id, session_id=session_id)
+
+        # if QUIT succeeded, remove the session from active connection list
+        if payload.ftp_command is FTPCommand.QUIT and payload.status_code is FTPStatusCode.OK:
+            self.remove_connection(connection_id=session_id)
+
         self.sys_log.info(f"{self.name}: Received FTP Response {payload.ftp_command.name} {payload.status_code.value}")
 
         self._process_ftp_command(payload=payload, session_id=session_id)

src/primaite/simulator/system/services/ftp/ftp_server.py

@@ -1,5 +1,4 @@
-from ipaddress import IPv4Address
-from typing import Any, Dict, Optional
+from typing import Any, Optional
 
 from primaite import getLogger
 from primaite.simulator.network.protocols.ftp import FTPCommand, FTPPacket, FTPStatusCode
@@ -21,9 +20,6 @@ class FTPServer(FTPServiceABC):
     server_password: Optional[str] = None
     """Password needed to connect to FTP server. Default is None."""
 
-    connections: Dict[str, IPv4Address] = {}
-    """Current active connections to the FTP server."""
-
     def __init__(self, **kwargs):
         kwargs["name"] = "FTPServer"
         kwargs["port"] = Port.FTP
@@ -41,7 +37,7 @@ class FTPServer(FTPServiceABC):
     def reset_component_for_episode(self, episode: int):
         """Reset the original state of the SimComponent."""
         _LOGGER.debug(f"Resetting FTPServer state on node {self.software_manager.node.hostname}")
-        self.connections.clear()
+        self.clear_connections()
         super().reset_component_for_episode(episode)
 
     def _process_ftp_command(self, payload: FTPPacket, session_id: Optional[str] = None, **kwargs) -> FTPPacket:
@@ -62,9 +58,6 @@ class FTPServer(FTPServiceABC):
 
         self.sys_log.info(f"{self.name}: Received FTP {payload.ftp_command.name} {payload.ftp_command_args}")
 
-        if session_id:
-            session_details = self._get_session_details(session_id)
-
         if payload.ftp_command is not None:
             self.sys_log.info(f"Received FTP {payload.ftp_command.name} command.")
 
@@ -73,7 +66,7 @@ class FTPServer(FTPServiceABC):
             # check that the port is valid
             if isinstance(payload.ftp_command_args, Port) and payload.ftp_command_args.value in range(0, 65535):
                 # return successful connection
-                self.connections[session_id] = session_details.with_ip_address
+                self.add_connection(connection_id=session_id, session_id=session_id)
                 payload.status_code = FTPStatusCode.OK
                 return payload
 
@@ -81,7 +74,7 @@ class FTPServer(FTPServiceABC):
             return payload
 
         if payload.ftp_command == FTPCommand.QUIT:
-            self.connections.pop(session_id)
+            self.remove_connection(connection_id=session_id)
             payload.status_code = FTPStatusCode.OK
             return payload
 

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

@@ -40,6 +40,12 @@ class Service(IOSoftware):
     restart_countdown: Optional[int] = None
     "If currently restarting, how many timesteps remain until the restart is finished."
 
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+
+        self.health_state_visible = SoftwareHealthState.UNUSED
+        self.health_state_actual = SoftwareHealthState.UNUSED
+
     def _can_perform_action(self) -> bool:
         """
         Checks if the service can perform actions.
@@ -52,7 +58,7 @@ class Service(IOSoftware):
         if not super()._can_perform_action():
             return False
 
-        if self.operating_state is not self.operating_state.RUNNING:
+        if self.operating_state is not ServiceOperatingState.RUNNING:
             # service is not running
             _LOGGER.error(f"Cannot perform action: {self.name} is {self.operating_state.name}")
             return False
@@ -74,12 +80,6 @@ class Service(IOSoftware):
         """
         return super().receive(payload=payload, session_id=session_id, **kwargs)
 
-    def __init__(self, **kwargs):
-        super().__init__(**kwargs)
-
-        self.health_state_visible = SoftwareHealthState.UNUSED
-        self.health_state_actual = SoftwareHealthState.UNUSED
-
     def set_original_state(self):
         """Sets the original state."""
         super().set_original_state()

src/primaite/simulator/system/software.py

@@ -1,4 +1,6 @@
+import copy
 from abc import abstractmethod
+from datetime import datetime
 from enum import Enum
 from ipaddress import IPv4Address
 from typing import Any, Dict, Optional
@@ -198,7 +200,7 @@ class IOSoftware(Software):
 
     installing_count: int = 0
     "The number of times the software has been installed. Default is 0."
-    max_sessions: int = 1
+    max_sessions: int = 100
     "The maximum number of sessions that the software can handle simultaneously. Default is 0."
     tcp: bool = True
     "Indicates if the software uses TCP protocol for communication. Default is True."
@@ -206,6 +208,8 @@ class IOSoftware(Software):
     "Indicates if the software uses UDP protocol for communication. Default is True."
     port: Port
     "The port to which the software is connected."
+    _connections: Dict[str, Dict] = {}
+    "Active connections."
 
     def set_original_state(self):
         """Sets the original state."""
@@ -250,6 +254,65 @@ class IOSoftware(Software):
             return False
         return True
 
+    @property
+    def connections(self) -> Dict[str, Dict]:
+        """Return the public version of connections."""
+        return copy.copy(self._connections)
+
+    def add_connection(self, connection_id: str, session_id: Optional[str] = None) -> bool:
+        """
+        Create a new connection to this service.
+
+        Returns true if connection successfully created
+
+        :param: connection_id: UUID of the connection to create
+        :type: string
+        """
+        # if over or at capacity, set to overwhelmed
+        if len(self._connections) >= self.max_sessions:
+            self.health_state_actual = SoftwareHealthState.OVERWHELMED
+            self.sys_log.error(f"{self.name}: Connect request for {connection_id=} declined. Service is at capacity.")
+            return False
+        else:
+            # if service was previously overwhelmed, set to good because there is enough space for connections
+            if self.health_state_actual == SoftwareHealthState.OVERWHELMED:
+                self.health_state_actual = SoftwareHealthState.GOOD
+
+            # check that connection already doesn't exist
+            if not self._connections.get(connection_id):
+                session_details = None
+                if session_id:
+                    session_details = self._get_session_details(session_id)
+                self._connections[connection_id] = {
+                    "ip_address": session_details.with_ip_address if session_details else None,
+                    "time": datetime.now(),
+                }
+                self.sys_log.info(f"{self.name}: Connect request for {connection_id=} authorised")
+                return True
+            # connection with given id already exists
+            self.sys_log.error(
+                f"{self.name}: Connect request for {connection_id=} declined. Connection already exists."
+            )
+            return False
+
+    def remove_connection(self, connection_id: str) -> bool:
+        """
+        Remove a connection from this service.
+
+        Returns true if connection successfully removed
+
+        :param: connection_id: UUID of the connection to create
+        :type: string
+        """
+        if self.connections.get(connection_id):
+            self._connections.pop(connection_id)
+            self.sys_log.info(f"{self.name}: Connection {connection_id=} closed.")
+            return True
+
+    def clear_connections(self):
+        """Clears all the connections from the software."""
+        self._connections = {}
+
     def send(
         self,
         payload: Any,