config.py 文件源码

def find_link_address(link_address: Optional[IPv6Address],
                          interface_addresses: Iterable[IPv6Address]) -> IPv6Address:
        """
        Find the appropriate reply-from address

        :param link_address: The link-address address specified in the configuration, if any
        :param interface_addresses: The list of addresses on the interface
        :return: The reply-from address to use
        """
        if link_address:
            return link_address
        else:
            # Pick the first global address
            global_addresses = [address for address in interface_addresses if is_global_unicast(address)]
            if global_addresses:
                return global_addresses[0]
            else:
                return IPv6Address('::')