Source code for dhcpkit.ipv6.server.extensions.relay_echo_request

Implementation of Echo Request option handling as specified in :rfc:`4994`.
from typing import List

from dhcpkit.ipv6.extensions.relay_echo_request import EchoRequestOption
from dhcpkit.ipv6.messages import RelayForwardMessage, RelayReplyMessage
from dhcpkit.ipv6.server.handlers import Handler, RelayHandler
from dhcpkit.ipv6.server.transaction_bundle import TransactionBundle

[docs]def create_cleanup_handlers() -> List[Handler]: """ Create handlers to clean up stuff in the transaction bundle :return: Handlers to add to the handler chain """ return [RelayEchoRequestOptionHandler()]
[docs]class RelayEchoRequestOptionHandler(RelayHandler): """ When a server creates a Relay-Reply, it SHOULD perform ERO processing after processing the ORO and other options processing. For each option in the ERO: a. If the option is already in the Relay-Reply, the server MUST ignore that option and continue to process any remaining options in the ERO. b. If the option was not in the received Relay-Forward, the server MUST ignore that option and continue to process any remaining options in the ERO. c. Otherwise, the server MUST copy the option, verbatim, from the received Relay-Forward to the Relay-Reply, even if the server does not otherwise recognize that option. """
[docs] def handle_relay(self, bundle: TransactionBundle, relay_message_in: RelayForwardMessage, relay_message_out: RelayReplyMessage): """ Handle the options for each relay message pair. :param bundle: The transaction bundle :param relay_message_in: The incoming relay message :param relay_message_out: Thr outgoing relay message """ # See if the relay message contains an ERO ero = relay_message_in.get_option_of_type(EchoRequestOption) if not ero: # Nothing to do return for option_type in ero.requested_options: # Don't do anything if the outgoing relay message already has this one if any(option.option_type == option_type for option in relay_message_out.options): continue # Get the incoming options of the requested type incoming_options = [option for option in relay_message_in.options if option.option_type == option_type] for option in incoming_options: # Make sure this option can go into this type of response if not relay_message_out.may_contain(option): return # And append them to the outgoing message if possible relay_message_out.options.append(option)