ICMP Class

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The ICMP class is used to facilitate ICMP communications. It can act both as a client and a server and can communicate with any number of hosts simultaneously. It also can generate and receive broadcast packets.

Syntax

class ipworks.ICMP

Remarks

The interface of the class is similar to the interface of TCPClient, only it is much simpler. The class is activated/deactivated by using the active property. This property enables or disables the sending or receiving of data. Data can be sent in the same way as TCPClient, using the send method and Text parameter. The destination is specified using the remote_host property. The class automatically creates an ICMP header containing message_type, message_sub_type, and a checksum for the message.

If the UseConnection configuration setting is set to True, then a local association is created with the remote host. Otherwise, the class can receive datagrams (packets) from any host and can send datagrams to any host. Packets can be broadcast on the local net by setting the destination to 255.255.255.255.

Inbound data is received through the on_data_in event.

The operation of the class is almost completely asynchronous. All the calls, except the ones that deal with domain name resolution, operate through Windows messages (no blocking calls). The gain in performance is considerable when compared with using blocking calls.

Property List

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The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

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The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

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The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

Config Settings

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The following is a list of config settings for the class with short descriptions. Click on the links for further details.

accept_data Property

This property indicates whether data reception is currently enabled.

Syntax

def get_accept_data() -> bool: ...

accept_data = property(get_accept_data, None)

Default Value

TRUE

Remarks

This property indicates whether data reception is currently enabled. When False, data reception is disabled and the on_data_in event will not fire. Use the pause_data and process_data methods to pause and resume data reception.

This property is read-only.

active Property

This property indicates whether the class is active.

Syntax

def get_active() -> bool: ...

active = property(get_active, None)

Default Value

FALSE

Remarks

This property indicates whether the class is currently active and can send or receive data.

If the UseConnection configuration setting is set to True, then a local association (connection) to the remote host also is created. Use the activate and deactivate methods to control whether the class is active.

This property is read-only.

dont_route Property

If this property is set to True, it forces the socket to send data directly to the interface (no routing).

Syntax

def get_dont_route() -> bool: ...
def set_dont_route(value: bool) -> None: ...

dont_route = property(get_dont_route, set_dont_route)

Default Value

FALSE

Remarks

If this property is set to True, it forces the socket to send data directly to the interface (no routing). Normally, IP sockets send packets of data through routers and gateways until they reach the final destination. If this property is set to True, then data will be delivered on the local subnet only.

local_host Property

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

def get_local_host() -> str: ...
def set_local_host(value: str) -> None: ...

local_host = property(get_local_host, set_local_host)

Default Value

""

Remarks

This property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.

If the class is connected, the local_host property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

Note: local_host is not persistent. You must always set it in code, and never in the property window.

message_sub_type Property

This property is the subtype of the ICMP message (part of the ICMP header).

Syntax

def get_message_sub_type() -> int: ...
def set_message_sub_type(value: int) -> None: ...

message_sub_type = property(get_message_sub_type, set_message_sub_type)

Default Value

0

Remarks

This property contains the subtype of the ICMP message (part of the ICMP header). The ICMP message subtype (also referred to as "code") is a byte value representing the message subclass. Its meaning is associated with the message_type.

Types and subtypes of ICMP messages are defined in the various internet RFCs and other documentation associated with Transmission Control Protocol (TCP)/IP.

message_type Property

This property includes the type of the ICMP message (part of the ICMP header).

Syntax

def get_message_type() -> int: ...
def set_message_type(value: int) -> None: ...

message_type = property(get_message_type, set_message_type)

Default Value

0

Remarks

This property contains the type of the ICMP message (part of the ICMP header). The ICMP message type is a byte value representing the message class. The message type defines the structure and meaning of the message data assigned to Text parameter of the send method.

Types for ICMP messages are defined in the various internet RFCs and other documentation associated with Transmission Control Protocol (TCP/IP). The following are a few examples of ICMP message types:

remote_host Property

This property includes the address of the RemoteHost. Domain names are resolved to IP addresses.

Syntax

def get_remote_host() -> str: ...
def set_remote_host(value: str) -> None: ...

remote_host = property(get_remote_host, set_remote_host)

Default Value

""

Remarks

This property specifies the IP address (IP number in dotted internet format) or the domain name of the remote host.

If this property is set to 255.255.255.255, the class broadcasts data on the local subnet.

If this property is set to a domain name, a DNS request is initiated. Upon successful termination of the request, the property is set to the corresponding address. If the search is not successful, the class fails with an error.

If UseConnection is True, this property must be set before the class is activated (active is set to True).

timeout Property

This property specifies the timeout for the class.

Syntax

def get_timeout() -> int: ...
def set_timeout(value: int) -> None: ...

timeout = property(get_timeout, set_timeout)

Default Value

0

Remarks

If the timeout property is set to 0, all operations return immediately, potentially failing with an WOULDBLOCK error if data cannot be sent or received immediately.

If timeout is set to a positive value, the class will automatically retry each operation that otherwise would result in a WOULDBLOCK error for a maximum of timeout seconds.

The class will use do_events to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not freeze and remains responsive.

If timeout expires, and the operation is not yet complete, the class fails with an error.

Note: By default, all timeouts are inactivity timeouts, that is, the timeout period is extended by timeout seconds when any amount of data is successfully sent or received.

The default value for the timeout property is 0 (asynchronous operation).

time_to_live Property

This property includes the time-to-live (TTL) value for the ICMP packets sent by the class.

Syntax

def get_time_to_live() -> int: ...
def set_time_to_live(value: int) -> None: ...

time_to_live = property(get_time_to_live, set_time_to_live)

Default Value

0

Remarks

This method contains the time-to-live (TTL) value for the ICMP packets sent by the class. The TTL field of the ICMP packet is a counter limiting the lifetime of a packet.

Each router (or other module) that handles a packet decrements the TTL field by one or more if it holds the packet for more than one second. Thus, the TTL value is effectively a hop count limit on how far a datagram can propagate through the internet. When the TTL value is reduced to zero (or less), the packet is discarded.

If the value of the property is set to zero, then the default TTL value of the underlying Transmission Control Protocol (TCP)/IP subsystem will be used.

activate Method

This method enables sending and receiving of data.

Syntax

def activate() -> None: ...

Remarks

This method enables sending and receiving of data. When called, the class will create a communication endpoint (socket) that can be used for sending and receiving ICMP messages. This method must be called before using the class to send and receive data.

If the UseConnection configuration setting is set to True, then a local association (connection) to the remote host also is created.

config Method

Sets or retrieves a configuration setting.

Syntax

def config(configuration_string: str) -> str: ...

Remarks

config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

deactivate Method

This method disables sending and receiving of data.

Syntax

def deactivate() -> None: ...

Remarks

This method disables sending and receiving of data. When called, the class will destroy the existing socket and disable data communications.

do_events Method

This method processes events from the internal message queue.

Syntax

def do_events() -> None: ...

Remarks

When do_events is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

pause_data Method

This method pauses data reception.

Syntax

def pause_data() -> None: ...

Remarks

This method pauses data reception when called. While data reception is paused, the on_data_in event will not fire. Call process_data to reenable data reception.

process_data Method

This method reenables data reception after a call to PauseData .

Syntax

def process_data() -> None: ...

Remarks

This method reenables data reception after a previous call to pause_data. When pause_data is called, the on_data_in event will not fire. To reenable data reception and allow on_data_in to fire, call this method.

Note: This method is used only after previously calling pause_data. It does not need to be called to process incoming data by default.

reset Method

This method will reset the class.

Syntax

def reset() -> None: ...

Remarks

This method will reset the class's properties to their default values.

resolve_remote_host Method

This method resolves the hostname in RemoteHost to an IP address.

Syntax

def resolve_remote_host() -> None: ...

Remarks

This method resolves the hostname specified by remote_host to an IP address. The resolved value is available in the remote_host property after this method returns.

In most cases, calling this method is not necessary; the class will resolve the hostname automatically when needed. If DelayHostResolution is True, this method may be called to manually resolve remote_host, if desired.

send Method

This method sends data to the remote host.

Syntax

def send(text: bytes) -> None: ...

Remarks

This method sends data to the remote host.

send_bytes Method

This method sends data to the remote host.

Syntax

def send_bytes(data: bytes) -> None: ...

Remarks

This method sends data to the remote host. Calling this method is equivalent to calling the send_bytes/send_text method.

send_text Method

This method sends data to the remote host.

Syntax

def send_text(text: str) -> None: ...

Remarks

This method sends data to the remote host. Calling this method is equivalent to calling the send_bytes/send_text method.

on_data_in Event

This event is fired when a new ICMP messages come in.

Syntax

class ICMPDataInEventParams(object):
  @property
  def message_type() -> int: ...

  @property
  def message_sub_type() -> int: ...

  @property
  def message_data() -> bytes: ...

  @property
  def checksum() -> int: ...

  @property
  def source_address() -> str: ...

# In class ICMP:
@property
def on_data_in() -> Callable[[ICMPDataInEventParams], None]: ...
@on_data_in.setter
def on_data_in(event_hook: Callable[[ICMPDataInEventParams], None]) -> None: ...

Remarks

The MessageType parameter shows the type of the ICMP messages and the MessageSubType parameter shows its subtype.

The MessageData parameter contains the message data.

The Checksum parameter is True or False depending on the ICMP checksum validation on the message.

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

on_error Event

Fired when information is available about errors during data delivery.

Syntax

class ICMPErrorEventParams(object):
  @property
  def error_code() -> int: ...

  @property
  def description() -> str: ...

# In class ICMP:
@property
def on_error() -> Callable[[ICMPErrorEventParams], None]: ...
@on_error.setter
def on_error(event_hook: Callable[[ICMPErrorEventParams], None]) -> None: ...

Remarks

The on_error event is fired in case of exceptional conditions during message processing. Normally the class fails with an error.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

on_ready_to_send Event

This event is fired when the class is ready to send data.

Syntax

class ICMPReadyToSendEventParams(object):
# In class ICMP:
@property
def on_ready_to_send() -> Callable[[ICMPReadyToSendEventParams], None]: ...
@on_ready_to_send.setter
def on_ready_to_send(event_hook: Callable[[ICMPReadyToSendEventParams], None]) -> None: ...

Remarks

The on_ready_to_send event indicates that the underlying Transmission Control Protocol (TCP)/IP subsystem is ready to accept data after a failed send.

ICMP Config Settings

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the config method.

ICMP Config Settings

Socket Config Settings

Base Config Settings

ICMP Errors

ICMP Errors

SSL Errors

TCP/IP Errors