# Copyright 2016, Tresys Technology, LLC
#
# SPDX-License-Identifier: LGPL-2.1-only
#
from typing import NamedTuple
from ..policyrep import Context, Portcon
from .context import ContextWrapper
from .descriptors import DiffResultDescriptor
from .difference import Difference, Wrapper
class ModifiedPortcon(NamedTuple):
"""Difference details for a modified portcon."""
rule: Portcon
added_context: Context
removed_context: Context
class PortconsDifference(Difference):
"""Determine the difference in portcons between two policies."""
added_portcons = DiffResultDescriptor("diff_portcons")
removed_portcons = DiffResultDescriptor("diff_portcons")
modified_portcons = DiffResultDescriptor("diff_portcons")
def diff_portcons(self) -> None:
"""Generate the difference in portcons between the policies."""
self.log.info("Generating portcon differences from {0.left_policy} to {0.right_policy}".
format(self))
self.added_portcons, self.removed_portcons, matched_portcons = self._set_diff(
(PortconWrapper(n) for n in self.left_policy.portcons()),
(PortconWrapper(n) for n in self.right_policy.portcons()))
self.modified_portcons = []
for left_portcon, right_portcon in matched_portcons:
# Criteria for modified portcons
# 1. change to context
if ContextWrapper(left_portcon.context) != ContextWrapper(right_portcon.context):
self.modified_portcons.append(ModifiedPortcon(left_portcon,
right_portcon.context,
left_portcon.context))
#
# Internal functions
#
def _reset_diff(self) -> None:
"""Reset diff results on policy changes."""
self.log.debug("Resetting portcon differences")
self.added_portcons = None
self.removed_portcons = None
self.modified_portcons = None
class PortconWrapper(Wrapper[Portcon]):
"""Wrap portcon statements for diff purposes."""
__slots__ = ("protocol", "low", "high")
def __init__(self, ocon: Portcon) -> None:
self.origin = ocon
self.protocol = ocon.protocol
self.low, self.high = ocon.ports
self.key = hash(ocon)
def __hash__(self):
return self.key
def __lt__(self, other):
return self.origin < other.origin
def __eq__(self, other):
return self.protocol == other.protocol and \
self.low == other.low and \
self.high == other.high
