# -*- coding: utf-8 -*-
#
# Copyright (C) 2013 Branko Majic
#
# This file is part of Django Conntrackt.
#
# Django Conntrackt is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# Django Conntrackt 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 General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# Django Conntrackt. If not, see .
#
# Django imports.
from django.contrib.admin.util import NestedObjects
from django.core.exceptions import ValidationError
from django.core.urlresolvers import reverse
from django.db import models
from django.db.models.query_utils import Q
from django.utils.html import format_html
from django.utils.text import capfirst
class SearchManager(models.Manager):
"""
Custom model manager that implements search for model instances that contain
a specific string (search term) in fields "name" or "description".
"""
def search(self, search_term):
"""
Performs a search for model instances that contain the provided search
term in fields "name" or "description". The search is case-insensitive.
Arguments:
search_term - String to search the name and description for.
Returns:
Query set with model instances that matched the search.
"""
return self.filter(Q(name__icontains=search_term) | Q(description__icontains=search_term))
class RelatedCollectorMixin(object):
"""
Implements model mixin for easily obtainning related items of a model
instance.
The mixin can be used for obtaining all model objects that are directly or
indirectly linked to the calling model object (through foreign key
relationships).
This mixin is very useful in delete views for warning the user about all of
the related items that will be deleted if the calling item is deleted as
well.
"""
def get_dependant_objects(self):
"""
Creates a list of model objects that depend (reference), both directly
and indirectly, on calling model object. The calling model object is
included as the first element of the list. This method call can be used
in order to obtain a list of model objects that would get deleted in
case the calling model object gets deleted.
Returns:
Nested list of model objects that depend (reference) calling model
object.
"""
collector = NestedObjects(using='default')
collector.collect([self])
return collector.nested()
def get_dependant_objects_representation(self):
"""
Creates a nested list of object representations that depend (reference),
both directly and indirectly, calling model object. This method call can
be used in order to obtain a list of string representations of model
objects that would get deleted in case the calling model object gets
deleted.
The resulting nested list can be shown to the user for
warning/notification purposes using the unordered_list template tag.
Each non-list element will be a string of format:
MODEL_NAME: OBJECT_REPRESENTATION
If object has a callable get_absolute_url method, the object
representation will be surrouned by HTML anchor tag () where
target (href) is set to the value of get_absolute_url() method call.
Returns:
Nested list of representations of model objects that depend
(reference) calling model object.
"""
collector = NestedObjects(using='default')
collector.collect([self])
def formatter_callback(obj):
"""
Creates model object representation in format:
MODEL_NAME: OBJECT_REPRESENTATION
If passed object has a callable get_absolute_url method, the
instance representation will be surrouned by an HTML anchor
() where target is set to value of the get_absolute_url()
method call.
Arguments:
obj - Model object whose representation should be returned.
Returns:
String represenation of passed model object.
"""
try:
return format_html('{0}: {2}', capfirst(obj._meta.verbose_name), obj.get_absolute_url(), str(obj))
except AttributeError:
return format_html('{0}: {1}', capfirst(obj._meta.verbose_name), str(obj))
return collector.nested(formatter_callback)
class Project(RelatedCollectorMixin, models.Model):
"""
Implements a model with information about a project. A project has some
basic settings, and mainly serves the purpose of grouping entities for
easier handling and administration.
Fields:
name - String denoting the project name.
description - Free-form description of the project.
"""
name = models.CharField(max_length=100, unique=True)
description = models.TextField(blank=True)
objects = SearchManager()
deletion_collect_models = ["Entity", "Interface"]
class Meta:
permissions = (("view", "Can view information"),)
def __unicode__(self):
"""
Returns:
String representation of a project.
"""
return self.name
def get_absolute_url(self):
"""
Return absolute URL for viewing a single project.
"""
return reverse("project", kwargs={'pk': self.pk})
class Location(RelatedCollectorMixin, models.Model):
"""
Implements a model with information about location. Locations can further be
assigned to entities, letting the user group different servers and equipment
based on location.
Locations are not tied to specific project, and they do not have to be
actual physical locations. Such generic locations are therefore reusable
accross multiple projects.
For example, locations can be:
- Main site
- Backup site
- Disaster recovery site
- Belgrade
- Stockholm
Fields:
name - String denoting the location name.
description - Free-form description of a location.
"""
name = models.CharField(max_length=100, unique=True)
description = models.TextField(blank=True)
def __unicode__(self):
"""
Returns:
String representation of a location.
"""
return self.name
class Entity(RelatedCollectorMixin, models.Model):
"""
Models an entity in a project. An entity can be a server, router, or any
other piece of networking equipment that has its own IP address.
Entities can also be used for representing subnets etc. This is useful when
the communication restrictions need to be applied across a subnet.
Entities are tied to specific projects and locations.
Fields:
name - String denoting the entity name.
description - Free-form description of an entity.
project - Foreign key pointing to the project to which the entity
belongs.
location - Foreign key pointing to the location at which the entity is
located.
"""
name = models.CharField(max_length=100)
description = models.TextField(blank=True)
project = models.ForeignKey(Project)
location = models.ForeignKey(Location)
objects = SearchManager()
class Meta:
# Fix the plural form used by Django.
verbose_name_plural = 'entities'
# Enforce uniqueness of entity name in a project.
unique_together = ("name", "project")
def __unicode__(self):
"""
Returns:
String representation of an entity. This identifier contains name of
entity, its project name, and location name.
"""
return "%s (%s - %s)" % (self.name, self.project, self.location)
def incoming_communications(self):
"""
Returns:
List of incoming communications for an entity.
"""
communications = []
for interface in self.interface_set.all():
for communication in interface.destination_set.all():
communications.append(communication)
return communications
def outgoing_communications(self):
"""
Returns:
List of outgoing communications for an entity.
"""
communications = []
for interface in self.interface_set.all():
for communication in interface.source_set.all():
communications.append(communication)
return communications
def get_absolute_url(self):
"""
Return absolute URL for viewing a single entity.
"""
return reverse("entity", kwargs={'pk': self.pk})
def clean(self):
"""
Performs additional validation checks on the submitted data. It will
verify the following:
- That entity is not linked to any other entity in case of project
change.
"""
# Perform the check if entity is being updated.
if self.pk:
# Fetch the old data from database.
# @TODO: Is it better to do copying during __init__ instead?
old_object = Entity.objects.get(pk=1)
# Make sure that entity has no communications in current project if
# moving it around.
if self.project != old_object.project and (self.incoming_communications() or self.outgoing_communications()):
raise ValidationError("The entity cannot be moved to different project as long as it has valid communications with entities in current project.")
class Interface(RelatedCollectorMixin, models.Model):
"""
Models a representation of an interface on an entity. It can be used for
representing the subnets as well.
Each interface is coupled with a specific Entity.
Fields:
name - String denoting the interface name. For example 'eth0', 'eth1'
etc.
description - Free-form description of an interface.
entity - Foreign key pointing to the entity to which the interface
belongs.
address - IP address of an interface. It's possible to store network
address in it as well.
netmask - Netmask of the interface. By default this is /32
(255.255.255.255), but in case of subnet entities this can be used for
denoting the network netmask.
"""
name = models.CharField(max_length=100, default='eth0')
description = models.TextField(blank=True, default='Main network interface.')
entity = models.ForeignKey(Entity)
address = models.IPAddressField()
netmask = models.IPAddressField(default='255.255.255.255')
class Meta:
# Enforce uniqueness of interface name in an entity. Enforce uniqueness
# of IP address in a subnet for an entity.
unique_together = (("name", "entity"),
("entity", "address", "netmask"),)
def __unicode__(self):
"""
Returns:
String representation of an interface. In case of single IP this will
simply be the interface name and IP address. In case of subnet it will
include the netmask as well.
"""
if self.netmask == '255.255.255.255':
return '%s (%s)' % (self.entity.name, self.address)
else:
return '%s (%s/%s)' % (self.entity.name, self.address, self.netmask)
class Communication(RelatedCollectorMixin, models.Model):
"""
Models a representation of allowed network communication. This lets the user
display the possible network connections that should be allowed. Information
from the communication instances is also used for generating the iptables
rules for the entities.
Communication instances allow the user to specify one of the three possible
protocols and related information:
- TCP, along with the TCP port.
- UDP, along with the UDP port.
- ICMP, along with the ICMP type.
Allowed communication is always represented as combination of source
interface, destination interface, protocol, and port/ICMP type.
Fields:
source - Foreign key to the source (originating) interface. The
communication is expected to come _from_ the source.
destination - Foreign key to the destination interface. The destination
interface is expected to be able to accept incoming connections
(i.e. entity's servers are listening on those).
protocol - Textual field denoting the protocol that is used for
communication. This can be 'TCP', 'UDP', or 'ICMP'.
port - Port number used by the protocol. In case of ICMP, this is an ICMP
type (in numeric form).
description - Free-form text that can be used to describe the
communication. This is also used when generating the iptables rules for
documenting the rules.
"""
PROTOCOL_CHOICES = (
('TCP', 'TCP'),
('UDP', 'UDP'),
('ICMP', 'ICMP'),
)
source = models.ForeignKey(Interface, related_name='source_set')
destination = models.ForeignKey(Interface, related_name='destination_set')
protocol = models.CharField(max_length=10, choices=PROTOCOL_CHOICES)
port = models.IntegerField(default=0)
description = models.TextField(blank=True)
class Meta:
# Enforce uniqueness of communication.
unique_together = ("source", "destination", "protocol", "port")
def __unicode__(self):
"""
Returns:
String representation of an interface. This involves showing the
source and destination _entity_ name, protocol, and port.
"""
return "%s -> %s (%s:%s)" % (self.source.entity.name, self.destination.entity.name, self.protocol, self.port)
def clean(self):
"""
Performs additional validation checks on the submitted data. It will
verify the following:
- That source and destination interface belongs to distinct entities.
- That the specified protocol is supported.
"""
if self.source.entity == self.destination.entity:
raise ValidationError('Source and destination entities are identical.')
if self.source.entity.project != self.destination.entity.project:
raise ValidationError('Source and destination entities do not belong to the same project')
if (self.protocol.upper(), self.protocol.upper()) not in self.PROTOCOL_CHOICES:
raise ValidationError('%s is not a supported protocol.' % self.protocol)
def edit_link(self):
"""
This method is used for providing an additional 'Edit' link in the admin
site for the communication instances (for the display_list).
This provides ability to let all of the other fields of a communication
instance to be editable.
"""
return "Edit"
def source_representation(self):
"""
Produces string representation of communication that includes only the
source interface information.
The method is useful where the destination context is well known.
Returns:
Communication representation that includes only information about
the source interface.
"""
return "%s - %s: %d" % (self.source, self.protocol, self.port)
def destination_representation(self):
"""
Produces string representation of communication that includes only the
destination interface information.
The method is useful where the source context is well known.
Returns:
Communication representation that includes only information about
the destination interface.
"""
return "%s - %s: %d" % (self.destination, self.protocol, self.port)