Source code for dhcpkit.ipv6.server.utils

Utility functions for the DHCP server
import logging
import netifaces

from dhcpkit.ipv6.duids import LinkLayerDUID
from dhcpkit.utils import normalise_hex

logger = logging.getLogger(__name__)

[docs]def determine_local_duid() -> LinkLayerDUID: """ Calculate our own DUID based on one of our MAC addresses :return: The server DUID """ for interface_name in netifaces.interfaces(): link_addresses = netifaces.ifaddresses(interface_name).get(netifaces.AF_LINK, []) link_addresses = [link_address['addr'] for link_address in link_addresses if link_address.get('addr')] for link_address in link_addresses: try: # Build a DUID from this address ll_addr = bytes.fromhex(normalise_hex(link_address)) if len(ll_addr) != 6 or ll_addr == b'\x00\x00\x00\x00\x00\x00': # If it is not 6 bytes long then it is not an ethernet MAC address, and all-zeroes is just a fake continue # Assume it's ethernet, build a DUID duid = LinkLayerDUID(hardware_type=1, link_layer_address=ll_addr) logger.debug("Using server DUID based on {} link address: {}".format(interface_name, link_address)) return duid except ValueError: # Try the next one pass # We didn't find a useful server DUID raise ValueError("Cannot find a usable server DUID")