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

from __future__ import annotations

import re
import secrets
from enum import Enum
from ipaddress import IPv4Address, IPv4Network
from typing import Dict, List, Optional, Tuple, Union

from prettytable import PrettyTable

from primaite import getLogger
from primaite.exceptions import NetworkError
from primaite.simulator.core import SimComponent
from primaite.simulator.file_system.file_system import FileSystem
from primaite.simulator.network.protocols.arp import ARPEntry, ARPPacket
from primaite.simulator.network.transmission.data_link_layer import EthernetHeader, Frame
from primaite.simulator.network.transmission.network_layer import ICMPPacket, ICMPType, IPPacket, IPProtocol
from primaite.simulator.network.transmission.transport_layer import Port, TCPHeader
from primaite.simulator.system.core.packet_capture import PacketCapture
from primaite.simulator.system.core.session_manager import SessionManager
from primaite.simulator.system.core.software_manager import SoftwareManager
from primaite.simulator.system.core.sys_log import SysLog

_LOGGER = getLogger(__name__)


def generate_mac_address(oui: Optional[str] = None) -> str:
    """
    Generate a random MAC Address.

    :Example:

    >>> generate_mac_address()
    'ef:7e:97:c8:a8:ce'

    >>> generate_mac_address(oui='aa:bb:cc')
    'aa:bb:cc:42:ba:41'

    :param oui: The Organizationally Unique Identifier (OUI) portion of the MAC address. It should be a string with
        the first 3 bytes (24 bits) in the format "XX:XX:XX".
    :raises ValueError: If the 'oui' is not in the correct format (hexadecimal and 6 characters).
    """
    random_bytes = [secrets.randbits(8) for _ in range(6)]

    if oui:
        oui_pattern = re.compile(r"^([0-9A-Fa-f]{2}[:-]){2}[0-9A-Fa-f]{2}$")
        if not oui_pattern.match(oui):
            msg = f"Invalid oui. The oui should be in the format xx:xx:xx, where x is a hexadecimal digit, got '{oui}'"
            raise ValueError(msg)
        oui_bytes = [int(chunk, 16) for chunk in oui.split(":")]
        mac = oui_bytes + random_bytes[len(oui_bytes) :]
    else:
        mac = random_bytes

    return ":".join(f"{b:02x}" for b in mac)


class NIC(SimComponent):
    """
    Models a Network Interface Card (NIC) in a computer or network device.

    :param ip_address: The IPv4 address assigned to the NIC.
    :param subnet_mask: The subnet mask assigned to the NIC.
    :param gateway: The default gateway IP address for forwarding network traffic to other networks.
    :param mac_address: The MAC address of the NIC. Defaults to a randomly set MAC address.
    :param speed: The speed of the NIC in Mbps (default is 100 Mbps).
    :param mtu: The Maximum Transmission Unit (MTU) of the NIC in Bytes, representing the largest data packet size it
        can handle without fragmentation (default is 1500 B).
    :param wake_on_lan: Indicates if the NIC supports Wake-on-LAN functionality.
    :param dns_servers: List of IP addresses of DNS servers used for name resolution.
    """

    ip_address: IPv4Address
    "The IP address assigned to the NIC for communication on an IP-based network."
    subnet_mask: str
    "The subnet mask assigned to the NIC."
    gateway: IPv4Address
    "The default gateway IP address for forwarding network traffic to other networks. Randomly generated upon creation."
    mac_address: str
    "The MAC address of the NIC. Defaults to a randomly set MAC address."
    speed: int = 100
    "The speed of the NIC in Mbps. Default is 100 Mbps."
    mtu: int = 1500
    "The Maximum Transmission Unit (MTU) of the NIC in Bytes. Default is 1500 B"
    wake_on_lan: bool = False
    "Indicates if the NIC supports Wake-on-LAN functionality."
    dns_servers: List[IPv4Address] = []
    "List of IP addresses of DNS servers used for name resolution."
    connected_node: Optional[Node] = None
    "The Node to which the NIC is connected."
    connected_link: Optional[Link] = None
    "The Link to which the NIC is connected."
    enabled: bool = False
    "Indicates whether the NIC is enabled."
    pcap: Optional[PacketCapture] = None

    def __init__(self, **kwargs):
        """
        NIC constructor.

        Performs some type conversion the calls ``super().__init__()``. Then performs some checking on the ip_address
        and gateway just to check that it's all been configured correctly.

        :raises ValueError: When the ip_address and gateway are the same. And when the ip_address/subnet mask are a
            network address.
        """
        if not isinstance(kwargs["ip_address"], IPv4Address):
            kwargs["ip_address"] = IPv4Address(kwargs["ip_address"])
        if not isinstance(kwargs["gateway"], IPv4Address):
            kwargs["gateway"] = IPv4Address(kwargs["gateway"])
        if "mac_address" not in kwargs:
            kwargs["mac_address"] = generate_mac_address()
        super().__init__(**kwargs)

        if self.ip_address == self.gateway:
            msg = f"NIC ip address {self.ip_address} cannot be the same as the gateway {self.gateway}"
            _LOGGER.error(msg)
            raise ValueError(msg)
        if self.ip_network.network_address == self.ip_address:
            msg = (
                f"Failed to set IP address {self.ip_address} and subnet mask {self.subnet_mask} as it is a "
                f"network address {self.ip_network.network_address}"
            )
            _LOGGER.error(msg)
            raise ValueError(msg)

    @property
    def ip_network(self) -> IPv4Network:
        """
        Return the IPv4Network of the NIC.

        :return: The IPv4Network from the ip_address/subnet mask.
        """
        return IPv4Network(f"{self.ip_address}/{self.subnet_mask}", strict=False)

    def enable(self):
        """Attempt to enable the NIC."""
        if self.enabled:
            return
        if not self.connected_node:
            _LOGGER.error(f"NIC {self} cannot be enabled as it is not connected to a Node")
            return
        if self.connected_node.operating_state != NodeOperatingState.ON:
            self.connected_node.sys_log.error(f"NIC {self} cannot be enabled as the endpoint is not turned on")
            return

        self.enabled = True
        self.connected_node.sys_log.info(f"NIC {self} enabled")
        self.pcap = PacketCapture(hostname=self.connected_node.hostname, ip_address=self.ip_address)
        if self.connected_link:
            self.connected_link.endpoint_up()

    def disable(self):
        """Disable the NIC."""
        if not self.enabled:
            return

        self.enabled = False
        if self.connected_node:
            self.connected_node.sys_log.info(f"NIC {self} disabled")
        else:
            _LOGGER.info(f"NIC {self} disabled")
        if self.connected_link:
            self.connected_link.endpoint_down()

    def connect_link(self, link: Link):
        """
        Connect the NIC to a link.

        :param link: The link to which the NIC is connected.
        :type link: :class:`~primaite.simulator.network.transmission.physical_layer.Link`
        """
        if self.connected_link:
            _LOGGER.error(f"Cannot connect Link to NIC ({self.mac_address}) as it already has a connection")
            return

        if self.connected_link == link:
            _LOGGER.error(f"Cannot connect Link to NIC ({self.mac_address}) as it is already connected")
            return

        # TODO: Inform the Node that a link has been connected
        self.connected_link = link
        _LOGGER.info(f"NIC {self} connected to Link {link}")

    def disconnect_link(self):
        """Disconnect the NIC from the connected Link."""
        if self.connected_link.endpoint_a == self:
            self.connected_link.endpoint_a = None
        if self.connected_link.endpoint_b == self:
            self.connected_link.endpoint_b = None
        self.connected_link = None

    def add_dns_server(self, ip_address: IPv4Address):
        """
        Add a DNS server IP address.

        :param ip_address: The IP address of the DNS server to be added.
        :type ip_address: ipaddress.IPv4Address
        """
        pass

    def remove_dns_server(self, ip_address: IPv4Address):
        """
        Remove a DNS server IP Address.

        :param ip_address: The IP address of the DNS server to be removed.
        :type ip_address: ipaddress.IPv4Address
        """
        pass

    def send_frame(self, frame: Frame) -> bool:
        """
        Send a network frame from the NIC to the connected link.

        :param frame: The network frame to be sent.
        :type frame: :class:`~primaite.simulator.network.osi_layers.Frame`
        """
        if self.enabled:
            frame.set_sent_timestamp()
            self.pcap.capture(frame)
            self.connected_link.transmit_frame(sender_nic=self, frame=frame)
            return True
        # Cannot send Frame as the NIC is not enabled
        return False

    def receive_frame(self, frame: Frame) -> bool:
        """
        Receive a network frame from the connected link if the NIC is enabled.

        The Frame is passed to the Node.

        :param frame: The network frame being received.
        :type frame: :class:`~primaite.simulator.network.osi_layers.Frame`
        """
        if self.enabled:
            frame.decrement_ttl()
            frame.set_received_timestamp()
            self.pcap.capture(frame)
            self.connected_node.receive_frame(frame=frame, from_nic=self)
            return True
        return False

    def describe_state(self) -> Dict:
        """
        Get the current state of the NIC as a dict.

        :return: A dict containing the current state of the NIC.
        """
        pass

    def apply_action(self, action: str):
        """
        Apply an action to the NIC.

        :param action: The action to be applied.
        :type action: str
        """
        pass

    def __str__(self) -> str:
        return f"{self.mac_address}/{self.ip_address}"


class SwitchPort(SimComponent):
    """
    Models a switch port in a network switch device.

    :param mac_address: The MAC address of the SwitchPort. Defaults to a randomly set MAC address.
    :param speed: The speed of the SwitchPort in Mbps (default is 100 Mbps).
    :param mtu: The Maximum Transmission Unit (MTU) of the SwitchPort in Bytes, representing the largest data packet
        size it can handle without fragmentation (default is 1500 B).
    """

    port_num: int = 1
    mac_address: str
    "The MAC address of the SwitchPort. Defaults to a randomly set MAC address."
    speed: int = 100
    "The speed of the SwitchPort in Mbps. Default is 100 Mbps."
    mtu: int = 1500
    "The Maximum Transmission Unit (MTU) of the SwitchPort in Bytes. Default is 1500 B"
    connected_node: Optional[Switch] = None
    "The Node to which the SwitchPort is connected."
    connected_link: Optional[Link] = None
    "The Link to which the SwitchPort is connected."
    enabled: bool = False
    "Indicates whether the SwitchPort is enabled."
    pcap: Optional[PacketCapture] = None

    def __init__(self, **kwargs):
        """The SwitchPort constructor."""
        if "mac_address" not in kwargs:
            kwargs["mac_address"] = generate_mac_address()
        super().__init__(**kwargs)

    def enable(self):
        """Attempt to enable the SwitchPort."""
        if self.enabled:
            return

        if not self.connected_node:
            _LOGGER.error(f"SwitchPort {self} cannot be enabled as it is not connected to a Node")
            return

        if self.connected_node.operating_state != NodeOperatingState.ON:
            self.connected_node.sys_log.info(f"SwitchPort {self} cannot be enabled as the endpoint is not turned on")
            return

        self.enabled = True
        self.connected_node.sys_log.info(f"SwitchPort {self} enabled")
        self.pcap = PacketCapture(hostname=self.connected_node.hostname)
        if self.connected_link:
            self.connected_link.endpoint_up()

    def disable(self):
        """Disable the SwitchPort."""
        if not self.enabled:
            return
        self.enabled = False
        if self.connected_node:
            self.connected_node.sys_log.info(f"SwitchPort {self} disabled")
        else:
            _LOGGER.info(f"SwitchPort {self} disabled")
        if self.connected_link:
            self.connected_link.endpoint_down()

    def connect_link(self, link: Link):
        """
        Connect the SwitchPort to a link.

        :param link: The link to which the SwitchPort is connected.
        """
        if self.connected_link:
            _LOGGER.error(f"Cannot connect link to SwitchPort {self.mac_address} as it already has a connection")
            return

        if self.connected_link == link:
            _LOGGER.error(f"Cannot connect Link to SwitchPort {self.mac_address} as it is already connected")
            return

        # TODO: Inform the Switch that a link has been connected
        self.connected_link = link
        _LOGGER.info(f"SwitchPort {self} connected to Link {link}")
        self.enable()

    def disconnect_link(self):
        """Disconnect the SwitchPort from the connected Link."""
        if self.connected_link.endpoint_a == self:
            self.connected_link.endpoint_a = None
        if self.connected_link.endpoint_b == self:
            self.connected_link.endpoint_b = None
        self.connected_link = None

    def send_frame(self, frame: Frame) -> bool:
        """
        Send a network frame from the SwitchPort to the connected link.

        :param frame: The network frame to be sent.
        """
        if self.enabled:
            self.pcap.capture(frame)
            self.connected_link.transmit_frame(sender_nic=self, frame=frame)
            return True
        # Cannot send Frame as the SwitchPort is not enabled
        return False

    def receive_frame(self, frame: Frame) -> bool:
        """
        Receive a network frame from the connected link if the SwitchPort is enabled.

        The Frame is passed to the Node.

        :param frame: The network frame being received.
        """
        if self.enabled:
            frame.decrement_ttl()
            self.pcap.capture(frame)
            self.connected_node.forward_frame(frame=frame, incoming_port=self)
            return True
        return False

    def describe_state(self) -> Dict:
        """
        Get the current state of the SwitchPort as a dict.

        :return: A dict containing the current state of the SwitchPort.
        """
        pass

    def apply_action(self, action: str):
        """
        Apply an action to the SwitchPort.

        :param action: The action to be applied.
        :type action: str
        """
        pass

    def __str__(self) -> str:
        return f"{self.mac_address}"


class Link(SimComponent):
    """
    Represents a network link between NIC<-->, NIC<-->SwitchPort, or SwitchPort<-->SwitchPort.

    :param endpoint_a: The first NIC or SwitchPort connected to the Link.
    :param endpoint_b: The second NIC or SwitchPort connected to the Link.
    :param bandwidth: The bandwidth of the Link in Mbps (default is 100 Mbps).
    """

    endpoint_a: Union[NIC, SwitchPort]
    "The first NIC or SwitchPort connected to the Link."
    endpoint_b: Union[NIC, SwitchPort]
    "The second NIC or SwitchPort connected to the Link."
    bandwidth: float = 100.0
    "The bandwidth of the Link in Mbps (default is 100 Mbps)."
    current_load: float = 0.0
    "The current load on the link in Mbps."

    def __init__(self, **kwargs):
        """
        Ensure that endpoint_a and endpoint_b are not the same NIC.

        Connect the link to the NICs after creation.

        :raises ValueError: If endpoint_a and endpoint_b are the same NIC.
        """
        if kwargs["endpoint_a"] == kwargs["endpoint_b"]:
            msg = "endpoint_a and endpoint_b cannot be the same NIC or SwitchPort"
            _LOGGER.error(msg)
            raise ValueError(msg)
        super().__init__(**kwargs)
        self.endpoint_a.connect_link(self)
        self.endpoint_b.connect_link(self)
        self.endpoint_up()

    @property
    def current_load_percent(self) -> str:
        """Get the current load formatted as a percentage string."""
        return f"{self.current_load / self.bandwidth:.5f}%"

    def endpoint_up(self):
        """Let the Link know and endpoint has been brought up."""
        if self.up:
            _LOGGER.info(f"Link {self} up")

    def endpoint_down(self):
        """Let the Link know and endpoint has been brought down."""
        if not self.up:
            self.current_load = 0.0
            _LOGGER.info(f"Link {self} down")

    @property
    def up(self) -> bool:
        """
        Informs whether the link is up.

        This is based upon both NIC endpoints being enabled.
        """
        return self.endpoint_a.enabled and self.endpoint_b.enabled

    def _can_transmit(self, frame: Frame) -> bool:
        if self.up:
            frame_size_Mbits = frame.size_Mbits  # noqa - Leaving it as Mbits as this is how they're expressed
            return self.current_load + frame_size_Mbits <= self.bandwidth
        return False

    def transmit_frame(self, sender_nic: Union[NIC, SwitchPort], frame: Frame) -> bool:
        """
        Send a network frame from one NIC or SwitchPort to another connected NIC or SwitchPort.

        :param sender_nic: The NIC or SwitchPort sending the frame.
        :param frame: The network frame to be sent.
        :return: True if the Frame can be sent, otherwise False.
        """
        can_transmit = self._can_transmit(frame)
        if not can_transmit:
            _LOGGER.info(f"Cannot transmit frame as {self} is at capacity")
            return False

        receiver = self.endpoint_a
        if receiver == sender_nic:
            receiver = self.endpoint_b
        frame_size = frame.size_Mbits

        if receiver.receive_frame(frame):
            # Frame transmitted successfully
            # Load the frame size on the link
            self.current_load += frame_size
            _LOGGER.info(
                f"Added {frame_size:.3f} Mbits to {self}, current load {self.current_load:.3f} Mbits "
                f"({self.current_load_percent})"
            )
            return True
        return False

    def reset_component_for_episode(self, episode: int):
        """
        Link reset function.

        Reset:
         - returns the link current_load to 0.
        """
        self.current_load = 0

    def describe_state(self) -> Dict:
        """
        Get the current state of the Link as a dict.

        :return: A dict containing the current state of the Link.
        """
        pass

    def apply_action(self, action: str):
        """
        Apply an action to the Link.

        :param action: The action to be applied.
        :type action: str
        """
        pass

    def __str__(self) -> str:
        return f"{self.endpoint_a}<-->{self.endpoint_b}"


class ARPCache:
    """
    The ARPCache (Address Resolution Protocol) class.

    Responsible for maintaining a mapping between IP addresses and MAC addresses (ARP cache) for the network. It
    provides methods for looking up, adding, and removing entries, and for processing ARPPackets.
    """

    def __init__(self, sys_log: "SysLog"):
        """
        Initialize an ARP (Address Resolution Protocol) cache.

        :param sys_log: The nodes sys log.
        """
        self.sys_log: "SysLog" = sys_log
        self.arp: Dict[IPv4Address, ARPEntry] = {}
        self.nics: Dict[str, "NIC"] = {}

    def _add_arp_cache_entry(self, ip_address: IPv4Address, mac_address: str, nic: NIC):
        """
        Add an ARP entry to the cache.

        :param ip_address: The IP address to be added to the cache.
        :param mac_address: The MAC address associated with the IP address.
        :param nic: The NIC through which the NIC with the IP address is reachable.
        """
        self.sys_log.info(f"Adding ARP cache entry for {mac_address}/{ip_address} via NIC {nic}")
        arp_entry = ARPEntry(mac_address=mac_address, nic_uuid=nic.uuid)
        self.arp[ip_address] = arp_entry

    def _remove_arp_cache_entry(self, ip_address: IPv4Address):
        """
        Remove an ARP entry from the cache.

        :param ip_address: The IP address to be removed from the cache.
        """
        if ip_address in self.arp:
            del self.arp[ip_address]

    def get_arp_cache_mac_address(self, ip_address: IPv4Address) -> Optional[str]:
        """
        Get the MAC address associated with an IP address.

        :param ip_address: The IP address to look up in the cache.
        :return: The MAC address associated with the IP address, or None if not found.
        """
        arp_entry = self.arp.get(ip_address)
        if arp_entry:
            return arp_entry.mac_address

    def get_arp_cache_nic(self, ip_address: IPv4Address) -> Optional[NIC]:
        """
        Get the NIC associated with an IP address.

        :param ip_address: The IP address to look up in the cache.
        :return: The NIC associated with the IP address, or None if not found.
        """
        arp_entry = self.arp.get(ip_address)
        if arp_entry:
            return self.nics[arp_entry.nic_uuid]

    def clear_arp_cache(self):
        """Clear the entire ARP cache, removing all stored entries."""
        self.arp.clear()

    def send_arp_request(self, target_ip_address: Union[IPv4Address, str]):
        """
        Perform a standard ARP request for a given target IP address.

        Broadcasts the request through all enabled NICs to determine the MAC address corresponding to the target IP
        address.

        :param target_ip_address: The target IP address to send an ARP request for.
        """
        for nic in self.nics.values():
            if nic.enabled:
                self.sys_log.info(f"Sending ARP request from NIC {nic} for ip {target_ip_address}")
                tcp_header = TCPHeader(src_port=Port.ARP, dst_port=Port.ARP)

                # Network Layer
                ip_packet = IPPacket(
                    src_ip=nic.ip_address,
                    dst_ip=target_ip_address,
                )
                # Data Link Layer
                ethernet_header = EthernetHeader(src_mac_addr=nic.mac_address, dst_mac_addr="ff:ff:ff:ff:ff:ff")
                arp_packet = ARPPacket(
                    sender_ip=nic.ip_address, sender_mac_addr=nic.mac_address, target_ip=target_ip_address
                )
                frame = Frame(ethernet=ethernet_header, ip=ip_packet, tcp=tcp_header, arp=arp_packet)
                nic.send_frame(frame)

    def process_arp_packet(self, from_nic: NIC, arp_packet: ARPPacket):
        """
        Process a received ARP packet, handling both ARP requests and responses.

        If an ARP request is received for the local IP, a response is sent back.
        If an ARP response is received, the ARP cache is updated with the new entry.

        :param from_nic: The NIC that received the ARP packet.
        :param arp_packet: The ARP packet to be processed.
        """
        # ARP Reply
        if not arp_packet.request:
            self.sys_log.info(
                f"Received ARP response for {arp_packet.sender_ip} from {arp_packet.sender_mac_addr} via NIC {from_nic}"
            )
            self._add_arp_cache_entry(
                ip_address=arp_packet.sender_ip, mac_address=arp_packet.sender_mac_addr, nic=from_nic
            )
            return

        # ARP Request
        self.sys_log.info(
            f"Received ARP request for {arp_packet.target_ip} from "
            f"{arp_packet.sender_mac_addr}/{arp_packet.sender_ip} "
        )

        # Unmatched ARP Request
        if arp_packet.target_ip != from_nic.ip_address:
            self.sys_log.info(f"Ignoring ARP request for {arp_packet.target_ip}")
            return

        # Matched ARP request
        self._add_arp_cache_entry(ip_address=arp_packet.sender_ip, mac_address=arp_packet.sender_mac_addr, nic=from_nic)
        arp_packet = arp_packet.generate_reply(from_nic.mac_address)
        self.sys_log.info(
            f"Sending ARP reply from {arp_packet.sender_mac_addr}/{arp_packet.sender_ip} "
            f"to {arp_packet.target_ip}/{arp_packet.target_mac_addr} "
        )

        tcp_header = TCPHeader(src_port=Port.ARP, dst_port=Port.ARP)

        # Network Layer
        ip_packet = IPPacket(
            src_ip=arp_packet.sender_ip,
            dst_ip=arp_packet.target_ip,
        )
        # Data Link Layer
        ethernet_header = EthernetHeader(
            src_mac_addr=arp_packet.sender_mac_addr, dst_mac_addr=arp_packet.target_mac_addr
        )
        frame = Frame(ethernet=ethernet_header, ip=ip_packet, tcp=tcp_header, arp=arp_packet)
        from_nic.send_frame(frame)


class ICMP:
    """
    The ICMP (Internet Control Message Protocol) class.

    Provides functionalities for managing and handling ICMP packets, including echo requests and replies.
    """

    def __init__(self, sys_log: SysLog, arp_cache: ARPCache):
        """
        Initialize the ICMP (Internet Control Message Protocol) service.

        :param sys_log: The system log to store system messages and information.
        :param arp_cache: The ARP cache for resolving IP to MAC address mappings.
        """
        self.sys_log: SysLog = sys_log
        self.arp: ARPCache = arp_cache

    def process_icmp(self, frame: Frame):
        """
        Process an ICMP packet, including handling echo requests and replies.

        :param frame: The Frame containing the ICMP packet to process.
        """
        if frame.icmp.icmp_type == ICMPType.ECHO_REQUEST:
            self.sys_log.info(f"Received echo request from {frame.ip.src_ip}")
            target_mac_address = self.arp.get_arp_cache_mac_address(frame.ip.src_ip)
            src_nic = self.arp.get_arp_cache_nic(frame.ip.src_ip)
            tcp_header = TCPHeader(src_port=Port.ARP, dst_port=Port.ARP)

            # Network Layer
            ip_packet = IPPacket(src_ip=src_nic.ip_address, dst_ip=frame.ip.src_ip, protocol=IPProtocol.ICMP)
            # Data Link Layer
            ethernet_header = EthernetHeader(src_mac_addr=src_nic.mac_address, dst_mac_addr=target_mac_address)
            icmp_reply_packet = ICMPPacket(
                icmp_type=ICMPType.ECHO_REPLY,
                icmp_code=0,
                identifier=frame.icmp.identifier,
                sequence=frame.icmp.sequence + 1,
            )
            frame = Frame(ethernet=ethernet_header, ip=ip_packet, tcp=tcp_header, icmp=icmp_reply_packet)
            self.sys_log.info(f"Sending echo reply to {frame.ip.dst_ip}")
            src_nic.send_frame(frame)
        elif frame.icmp.icmp_type == ICMPType.ECHO_REPLY:
            self.sys_log.info(f"Received echo reply from {frame.ip.src_ip}")

    def ping(
        self, target_ip_address: IPv4Address, sequence: int = 0, identifier: Optional[int] = None
    ) -> Tuple[int, Union[int, None]]:
        """
        Send an ICMP echo request (ping) to a target IP address and manage the sequence and identifier.

        :param target_ip_address: The target IP address to send the ping.
        :param sequence: The sequence number of the echo request. Defaults to 0.
        :param identifier: An optional identifier for the ICMP packet. If None, a default will be used.
        :return: A tuple containing the next sequence number and the identifier, or (0, None) if the target IP address
            was not found in the ARP cache.
        """
        nic = self.arp.get_arp_cache_nic(target_ip_address)
        # TODO: Eventually this ARP request needs to be done elsewhere. It's not the resonsibility of the
        # ping function to handle ARP lookups
        # No existing ARP entry
        if not nic:
            self.sys_log.info(f"No entry in ARP cache for {target_ip_address}")
            self.arp.send_arp_request(target_ip_address)
            return 0, None

        # ARP entry exists
        sequence += 1
        target_mac_address = self.arp.get_arp_cache_mac_address(target_ip_address)
        src_nic = self.arp.get_arp_cache_nic(target_ip_address)
        tcp_header = TCPHeader(src_port=Port.ARP, dst_port=Port.ARP)

        # Network Layer
        ip_packet = IPPacket(
            src_ip=nic.ip_address,
            dst_ip=target_ip_address,
            protocol=IPProtocol.ICMP,
        )
        # Data Link Layer
        ethernet_header = EthernetHeader(src_mac_addr=src_nic.mac_address, dst_mac_addr=target_mac_address)
        icmp_packet = ICMPPacket(identifier=identifier, sequence=sequence)
        frame = Frame(ethernet=ethernet_header, ip=ip_packet, tcp=tcp_header, icmp=icmp_packet)
        self.sys_log.info(f"Sending echo request to {target_ip_address}")
        nic.send_frame(frame)
        return sequence, icmp_packet.identifier


class NodeOperatingState(Enum):
    """Enumeration of Node Operating States."""

    OFF = 0
    "The node is powered off."
    ON = 1
    "The node is powered on."
    SHUTTING_DOWN = 2
    "The node is in the process of shutting down."
    BOOTING = 3
    "The node is in the process of booting up."


class Node(SimComponent):
    """
    A basic Node class that represents a node on the network.

    This class manages the state of the node, including the NICs (Network Interface Cards), accounts, applications,
    services, processes, file system, and various managers like ARP, ICMP, SessionManager, and SoftwareManager.

    :param hostname: The node hostname on the network.
    :param operating_state: The node operating state, either ON or OFF.
    """

    hostname: str
    "The node hostname on the network."
    operating_state: NodeOperatingState = NodeOperatingState.OFF
    "The hardware state of the node."
    nics: Dict[str, NIC] = {}
    "The NICs on the node."

    accounts: Dict = {}
    "All accounts on the node."
    applications: Dict = {}
    "All applications on the node."
    services: Dict = {}
    "All services on the node."
    processes: Dict = {}
    "All processes on the node."
    file_system: FileSystem
    "The nodes file system."
    sys_log: SysLog
    arp: ARPCache
    icmp: ICMP
    session_manager: SessionManager
    software_manager: SoftwareManager

    revealed_to_red: bool = False
    "Informs whether the node has been revealed to a red agent."

    def __init__(self, **kwargs):
        """
        Initialize the Node with various components and managers.

        This method initializes the ARP cache, ICMP handler, session manager, and software manager if they are not
        provided.
        """
        if not kwargs.get("sys_log"):
            kwargs["sys_log"] = SysLog(kwargs["hostname"])
        if not kwargs.get("arp_cache"):
            kwargs["arp"] = ARPCache(sys_log=kwargs.get("sys_log"))
        if not kwargs.get("icmp"):
            kwargs["icmp"] = ICMP(sys_log=kwargs.get("sys_log"), arp_cache=kwargs.get("arp"))
        if not kwargs.get("session_manager"):
            kwargs["session_manager"] = SessionManager(sys_log=kwargs.get("sys_log"), arp_cache=kwargs.get("arp"))
        if not kwargs.get("software_manager"):
            kwargs["software_manager"] = SoftwareManager(
                sys_log=kwargs.get("sys_log"), session_manager=kwargs.get("session_manager")
            )
        if not kwargs.get("file_system"):
            kwargs["file_system"] = FileSystem()
        super().__init__(**kwargs)
        self.arp.nics = self.nics

    def show(self):
        """Prints a table of the NICs on the Node.."""
        from prettytable import PrettyTable

        table = PrettyTable(["MAC Address", "Address", "Default Gateway", "Speed", "Status"])

        for nic in self.nics.values():
            table.add_row(
                [
                    nic.mac_address,
                    f"{nic.ip_address}/{nic.ip_network.prefixlen}",
                    nic.gateway,
                    nic.speed,
                    "Enabled" if nic.enabled else "Disabled",
                ]
            )
        print(table)

    def power_on(self):
        """Power on the Node, enabling its NICs if it is in the OFF state."""
        if self.operating_state == NodeOperatingState.OFF:
            self.operating_state = NodeOperatingState.ON
            self.sys_log.info("Turned on")
            for nic in self.nics.values():
                nic.enable()

    def power_off(self):
        """Power off the Node, disabling its NICs if it is in the ON state."""
        if self.operating_state == NodeOperatingState.ON:
            for nic in self.nics.values():
                nic.disable()
            self.operating_state = NodeOperatingState.OFF
            self.sys_log.info("Turned off")

    def connect_nic(self, nic: NIC):
        """
        Connect a NIC (Network Interface Card) to the node.

        :param nic: The NIC to connect.
        :raise NetworkError: If the NIC is already connected.
        """
        if nic.uuid not in self.nics:
            self.nics[nic.uuid] = nic
            nic.connected_node = self
            self.sys_log.info(f"Connected NIC {nic}")
            if self.operating_state == NodeOperatingState.ON:
                nic.enable()
        else:
            msg = f"Cannot connect NIC {nic} as it is already connected"
            self.sys_log.logger.error(msg)
            _LOGGER.error(msg)
            raise NetworkError(msg)

    def disconnect_nic(self, nic: Union[NIC, str]):
        """
        Disconnect a NIC (Network Interface Card) from the node.

        :param nic: The NIC to Disconnect, or its UUID.
        :raise NetworkError: If the NIC is not connected.
        """
        if isinstance(nic, str):
            nic = self.nics.get(nic)
        if nic or nic.uuid in self.nics:
            self.nics.pop(nic.uuid)
            nic.disable()
            self.sys_log.info(f"Disconnected NIC {nic}")
        else:
            msg = f"Cannot disconnect NIC {nic} as it is not connected"
            self.sys_log.logger.error(msg)
            _LOGGER.error(msg)
            raise NetworkError(msg)

    def ping(self, target_ip_address: Union[IPv4Address, str], pings: int = 4) -> bool:
        """
        Ping an IP address, performing a standard ICMP echo request/response.

        :param target_ip_address: The target IP address to ping.
        :param pings: The number of pings to attempt, default is 4.
        :return: True if the ping is successful, otherwise False.
        """
        if not isinstance(target_ip_address, IPv4Address):
            target_ip_address = IPv4Address(target_ip_address)
        if self.operating_state == NodeOperatingState.ON:
            self.sys_log.info(f"Attempting to ping {target_ip_address}")
            sequence, identifier = 0, None
            while sequence < pings:
                sequence, identifier = self.icmp.ping(target_ip_address, sequence, identifier)
            return True
        self.sys_log.info("Ping failed as the node is turned off")
        return False

    def send_frame(self, frame: Frame):
        """
        Send a Frame from the Node to the connected NIC.

        :param frame: The Frame to be sent.
        """
        nic: NIC = self._get_arp_cache_nic(frame.ip.dst_ip)
        nic.send_frame(frame)

    def receive_frame(self, frame: Frame, from_nic: NIC):
        """
        Receive a Frame from the connected NIC and process it.

        Depending on the protocol, the frame is passed to the appropriate handler such as ARP or ICMP, or up to the
        SessionManager if no code manager exists.

        :param frame: The Frame being received.
        :param from_nic: The NIC that received the frame.
        """
        if frame.ip.protocol == IPProtocol.TCP:
            if frame.tcp.src_port == Port.ARP:
                self.arp.process_arp_packet(from_nic=from_nic, arp_packet=frame.arp)
        elif frame.ip.protocol == IPProtocol.UDP:
            pass
        elif frame.ip.protocol == IPProtocol.ICMP:
            self.icmp.process_icmp(frame=frame)

    def describe_state(self) -> Dict:
        """
        Describe the state of the Node.

        :return: A dictionary representing the state of the node.
        """
        pass


class Switch(Node):
    """A class representing a Layer 2 network switch."""

    num_ports: int = 24
    "The number of ports on the switch."
    switch_ports: Dict[int, SwitchPort] = {}
    "The SwitchPorts on the switch."
    dst_mac_table: Dict[str, SwitchPort] = {}
    "A MAC address table mapping destination MAC addresses to corresponding SwitchPorts."

    def show(self):
        """Prints a table of the SwitchPorts on the Switch."""
        table = PrettyTable(["Port", "MAC Address", "Speed", "Status"])

        for port_num, port in self.switch_ports.items():
            table.add_row([port_num, port.mac_address, port.speed, "Enabled" if port.enabled else "Disabled"])
        print(table)

    def describe_state(self) -> Dict:
        """TODO."""
        pass

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        if not self.switch_ports:
            self.switch_ports = {i: SwitchPort() for i in range(1, self.num_ports + 1)}
        for port_num, port in self.switch_ports.items():
            port.connected_node = self
            port.port_num = port_num

    def _add_mac_table_entry(self, mac_address: str, switch_port: SwitchPort):
        mac_table_port = self.dst_mac_table.get(mac_address)
        if not mac_table_port:
            self.dst_mac_table[mac_address] = switch_port
            self.sys_log.info(f"Added MAC table entry: Port {switch_port.port_num} -> {mac_address}")
        else:
            if mac_table_port != switch_port:
                self.dst_mac_table.pop(mac_address)
                self.sys_log.info(f"Removed MAC table entry: Port {mac_table_port.port_num} -> {mac_address}")
                self._add_mac_table_entry(mac_address, switch_port)

    def forward_frame(self, frame: Frame, incoming_port: SwitchPort):
        """
        Forward a frame to the appropriate port based on the destination MAC address.

        :param frame: The Frame to be forwarded.
        :param incoming_port: The port number from which the frame was received.
        """
        src_mac = frame.ethernet.src_mac_addr
        dst_mac = frame.ethernet.dst_mac_addr
        self._add_mac_table_entry(src_mac, incoming_port)

        outgoing_port = self.dst_mac_table.get(dst_mac)
        if outgoing_port or dst_mac != "ff:ff:ff:ff:ff:ff":
            outgoing_port.send_frame(frame)
        else:
            # If the destination MAC is not in the table, flood to all ports except incoming
            for port in self.switch_ports.values():
                if port != incoming_port:
                    port.send_frame(frame)

    def disconnect_link_from_port(self, link: Link, port_number: int):
        """
        Disconnect a given link from the specified port number on the switch.

        :param link: The Link object to be disconnected.
        :param port_number: The port number on the switch from where the link should be disconnected.
        :raise NetworkError: When an invalid port number is provided or the link does not match the connection.
        """
        port = self.switch_ports.get(port_number)
        if port is None:
            msg = f"Invalid port number {port_number} on the switch"
            _LOGGER.error(msg)
            raise NetworkError(msg)

        if port.connected_link != link:
            msg = f"The link does not match the connection at port number {port_number}"
            _LOGGER.error(msg)
            raise NetworkError(msg)

        port.disconnect_link()