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# Copyright 2016, Tresys Technology, LLC
#
# This file is part of SETools.
#
# SETools is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation, either version 2.1 of
# the License, or (at your option) any later version.
#
# SETools is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with SETools. If not, see
# <http://www.gnu.org/licenses/>.
#
from collections import namedtuple
from .context import ContextWrapper
from .descriptors import DiffResultDescriptor
from .difference import Difference, Wrapper
modified_netifcon_record = namedtuple("modified_netifcon", ["rule",
"added_context",
"removed_context",
"added_packet",
"removed_packet"])
class NetifconsDifference(Difference):
"""Determine the difference in netifcons between two policies."""
added_netifcons = DiffResultDescriptor("diff_netifcons")
removed_netifcons = DiffResultDescriptor("diff_netifcons")
modified_netifcons = DiffResultDescriptor("diff_netifcons")
def diff_netifcons(self):
"""Generate the difference in netifcons between the policies."""
self.log.info("Generating netifcon differences from {0.left_policy} to {0.right_policy}".
format(self))
self.added_netifcons, self.removed_netifcons, matched_netifcons = self._set_diff(
(NetifconWrapper(n) for n in self.left_policy.netifcons()),
(NetifconWrapper(n) for n in self.right_policy.netifcons()))
self.modified_netifcons = []
for left_netifcon, right_netifcon in matched_netifcons:
# Criteria for modified netifcons
# 1. change to context
# 2. change to packet context
if ContextWrapper(left_netifcon.context) != ContextWrapper(right_netifcon.context):
removed_context = left_netifcon.context
added_context = right_netifcon.context
else:
removed_context = None
added_context = None
if ContextWrapper(left_netifcon.packet) != ContextWrapper(right_netifcon.packet):
removed_packet = left_netifcon.packet
added_packet = right_netifcon.packet
else:
removed_packet = None
added_packet = None
if removed_context or removed_packet:
self.modified_netifcons.append(modified_netifcon_record(
left_netifcon, added_context, removed_context, added_packet, removed_packet))
#
# Internal functions
#
def _reset_diff(self):
"""Reset diff results on policy changes."""
self.log.debug("Resetting netifcon differences")
self.added_netifcons = None
self.removed_netifcons = None
self.modified_netifcons = None
class NetifconWrapper(Wrapper):
"""Wrap netifcon statements for diff purposes."""
__slots__ = ("netif")
def __init__(self, ocon):
self.origin = ocon
self.netif = ocon.netif
self.key = hash(ocon)
def __hash__(self):
return self.key
def __lt__(self, other):
return self.netif < other.netif
def __eq__(self, other):
return self.netif == other.netif
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