re2o/machines/models.py

# -*- mode: python; coding: utf-8 -*-
# Re2o est un logiciel d'administration développé initiallement au rezometz. Il
# se veut agnostique au réseau considéré, de manière à être installable en
# quelques clics.
#
# Copyright © 2016-2018  Gabriel Détraz
# Copyright © 2017  Goulven Kermarec
# Copyright © 2017  Augustin Lemesle
# Copyright © 2018  Charlie Jacomme
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""machines.models
The models definitions for the Machines app
"""

from __future__ import unicode_literals

from datetime import timedelta
import re
from ipaddress import IPv6Address
from itertools import chain
from netaddr import mac_bare, EUI, IPSet, IPRange, IPNetwork, IPAddress
import hashlib
import base64

from django.db import models
from django.db.models import Q
from django.db.models.signals import post_save, post_delete
from django.dispatch import receiver
from django.forms import ValidationError
from django.utils.functional import cached_property
from django.utils import timezone
from django.core.validators import MaxValueValidator, MinValueValidator
from django.utils.translation import ugettext_lazy as _

from macaddress.fields import MACAddressField

from re2o.field_permissions import FieldPermissionModelMixin
from re2o.mixins import AclMixin, RevMixin

import users.models
import preferences.models


class Machine(RevMixin, FieldPermissionModelMixin, models.Model):
    """ Class définissant une machine, object parent user, objets fils
    interfaces"""
    user = models.ForeignKey('users.User', on_delete=models.PROTECT)
    name = models.CharField(
        max_length=255,
        help_text=_("Optional"),
        blank=True,
        null=True
    )
    active = models.BooleanField(default=True)

    class Meta:
        permissions = (
            ("view_machine", _("Can view a machine object")),
            ("change_machine_user",
             _("Can change the user of a machine")),
        )
        verbose_name = _("machine")
        verbose_name_plural = _("machines")

    @classmethod
    def get_instance(cls, machineid, *_args, **_kwargs):
        """Get the Machine instance with machineid.
        :param userid: The id
        :return: The user
        """
        return cls.objects.get(pk=machineid)

    def linked_objects(self):
        """Return linked objects : machine and domain.
        Usefull in history display"""
        return chain(
            self.interface_set.all(),
            Domain.objects.filter(
                interface_parent__in=self.interface_set.all()
            )
        )

    @staticmethod
    def can_change_user(user_request, *_args, **_kwargs):
        """Checks if an user is allowed to change the user who owns a
        Machine.

        Args:
            user_request: The user requesting to change owner.

        Returns:
            A tuple with a boolean stating if edition is allowed and an
            explanation message.
        """
        return (user_request.has_perm('machines.change_machine_user'),
                _("You don't have the right to change the machine's user."))

    @staticmethod
    def can_view_all(user_request, *_args, **_kwargs):
        """Vérifie qu'on peut bien afficher l'ensemble des machines,
        droit particulier correspondant
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        if not user_request.has_perm('machines.view_machine'):
            return False, _("You don't have the right to view all the"
                             " machines.")
        return True, None

    @staticmethod
    def can_create(user_request, userid, *_args, **_kwargs):
        """Vérifie qu'un user qui fait la requète peut bien créer la machine
        et n'a pas atteint son quota, et crée bien une machine à lui
        :param user_request: Utilisateur qui fait la requête
        :param userid: id de l'user dont on va créer une machine
        :return: soit True, soit False avec la raison de l'échec"""
        try:
            user = users.models.User.objects.get(pk=userid)
        except users.models.User.DoesNotExist:
            return False, _("Nonexistent user.")
        max_lambdauser_interfaces = (preferences.models.OptionalMachine
                                     .get_cached_value(
                                         'max_lambdauser_interfaces'
                                     ))
        if not user_request.has_perm('machines.add_machine'):
            if not (preferences.models.OptionalMachine
                    .get_cached_value('create_machine')):
                return False, (_("You don't have the right to add a machine."))
            if user != user_request:
                return False, (_("You don't have the right to add a machine"
                                 " to another user."))
            if user.user_interfaces().count() >= max_lambdauser_interfaces:
                return False, (_("You reached the maximum number of interfaces"
                                 " that you are allowed to create yourself"
                                 " (%s)." % max_lambdauser_interfaces))
        return True, None

    def can_edit(self, user_request, *args, **kwargs):
        """Vérifie qu'on peut bien éditer cette instance particulière (soit
        machine de soi, soit droit particulier
        :param self: instance machine à éditer
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison le cas échéant"""
        if self.user != user_request:
            if (not user_request.has_perm('machines.change_interface') or
                    not self.user.can_edit(
                        self.user,
                        user_request,
                        *args,
                        **kwargs
                    )[0]):
                return False, (_("You don't have the right to edit a machine"
                                 " of another user."))
        return True, None

    def can_delete(self, user_request, *args, **kwargs):
        """Vérifie qu'on peut bien supprimer cette instance particulière (soit
        machine de soi, soit droit particulier
        :param self: instance machine à supprimer
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        if self.user != user_request:
            if (not user_request.has_perm('machines.change_interface') or
                    not self.user.can_edit(
                        self.user,
                        user_request,
                        *args,
                        **kwargs
                    )[0]):
                return False, _("You don't have the right to delete a machine"
                                 " of another user.")
        return True, None

    def can_view(self, user_request, *_args, **_kwargs):
        """Vérifie qu'on peut bien voir cette instance particulière (soit
        machine de soi, soit droit particulier
        :param self: instance machine à éditer
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        if (not user_request.has_perm('machines.view_machine') and
                self.user != user_request):
            return False, _("You don't have the right to view other machines"
                             " than yours.")
        return True, None

    @cached_property
    def short_name(self):
        """Par defaut, renvoie le nom de la première interface
        de cette machine"""
        return str(self.interface_set.first().domain.name)

    @cached_property
    def complete_name(self):
        """Par defaut, renvoie le nom de la première interface
        de cette machine"""
        return str(self.interface_set.first())

    @cached_property
    def all_short_names(self):
        """Renvoie de manière unique, le nom des interfaces de cette
        machine"""
        return Domain.objects.filter(
            interface_parent__machine=self
            ).values_list('name', flat=True).distinct()

    @cached_property
    def all_complete_names(self):
        """Renvoie tous les tls complets de la machine"""
        return [str(domain) for domain in Domain.objects.filter(
            Q(cname__interface_parent__machine=self) | Q(interface_parent__machine=self)
            )]

    def __init__(self, *args, **kwargs):
        super(Machine, self).__init__(*args, **kwargs)
        self.field_permissions = {
            'user': self.can_change_user,
        }

    def __str__(self):
        return str(self.user) + ' - ' + str(self.id) + ' - ' + str(self.name)


class MachineType(RevMixin, AclMixin, models.Model):
    """ Type de machine, relié à un type d'ip, affecté aux interfaces"""
    type = models.CharField(max_length=255)
    ip_type = models.ForeignKey(
        'IpType',
        on_delete=models.PROTECT,
        blank=True,
        null=True
    )

    class Meta:
        permissions = (
            ("view_machinetype", _("Can view a machine type object")),
            ("use_all_machinetype", _("Can use all machine types")),
        )
        verbose_name = _("machine type")
        verbose_name_plural = _("machine types")

    def all_interfaces(self):
        """ Renvoie toutes les interfaces (cartes réseaux) de type
        machinetype"""
        return Interface.objects.filter(type=self)

    @staticmethod
    def can_use_all(user_request, *_args, **_kwargs):
        """Check if an user can use every MachineType.

        Args:
            user_request: The user requesting edition.
        Returns:
            A tuple with a boolean stating if user can acces and an explanation
            message is acces is not allowed.
        """
        if not user_request.has_perm('machines.use_all_machinetype'):
            return False, (_("You don't have the right to use all machine"
                             " types."))
        return True, None

    def __str__(self):
        return self.type


class IpType(RevMixin, AclMixin, models.Model):
    """ Type d'ip, définissant un range d'ip, affecté aux machine types"""
    type = models.CharField(max_length=255)
    extension = models.ForeignKey('Extension', on_delete=models.PROTECT)
    need_infra = models.BooleanField(default=False)
    domaine_ip_start = models.GenericIPAddressField(protocol='IPv4')
    domaine_ip_stop = models.GenericIPAddressField(protocol='IPv4')
    domaine_ip_network = models.GenericIPAddressField(
        protocol='IPv4',
        null=True,
        blank=True,
        help_text=_("Network containing the domain's IPv4 range (optional)")
    )
    domaine_ip_netmask = models.IntegerField(
        default=24,
        validators=[
            MaxValueValidator(31),
            MinValueValidator(8)
        ],
        help_text=_("Netmask for the domain's IPv4 range")
    )
    reverse_v4 = models.BooleanField(
            default=False, 
            help_text=_("Enable reverse DNS for IPv4"),
    )
    prefix_v6 = models.GenericIPAddressField(
        protocol='IPv6',
        null=True,
        blank=True
    )
    prefix_v6_length = models.IntegerField(
        default=64,
        validators=[
            MaxValueValidator(128),
            MinValueValidator(0)
        ]
        )
    reverse_v6 = models.BooleanField(
            default=False,
            help_text=_("Enable reverse DNS for IPv6"),
    )
    vlan = models.ForeignKey(
        'Vlan',
        on_delete=models.PROTECT,
        blank=True,
        null=True
    )
    ouverture_ports = models.ForeignKey(
        'OuverturePortList',
        blank=True,
        null=True
    )

    class Meta:
        permissions = (
            ("view_iptype", _("Can view an IP type object")),
            ("use_all_iptype", _("Can use all IP types")),
        )
        verbose_name = _("IP type")
        verbose_name_plural = ("IP types")

    @cached_property
    def ip_range(self):
        """ Renvoie un objet IPRange à partir de l'objet IpType"""
        return IPRange(self.domaine_ip_start, end=self.domaine_ip_stop)

    @cached_property
    def ip_set(self):
        """ Renvoie une IPSet à partir de l'iptype"""
        return IPSet(self.ip_range)

    @cached_property
    def ip_set_as_str(self):
        """ Renvoie une liste des ip en string"""
        return [str(x) for x in self.ip_set]

    @cached_property
    def ip_set_cidrs_as_str(self):
        """Renvoie la liste des cidrs du range en str"""
        return [str(ip_range) for ip_range in self.ip_set.iter_cidrs()]

    @cached_property
    def ip_set_full_info(self):
        """Iter sur les range cidr, et renvoie network, broacast , etc"""
        return [
            {
                'network': str(ip_set.network),
                'netmask': str(ip_set.netmask),
                'netmask_cidr': str(ip_set.prefixlen),
                'broadcast': str(ip_set.broadcast),
                'vlan': str(self.vlan),
                'vlan_id': self.vlan.vlan_id
            } for ip_set in self.ip_set.iter_cidrs()
        ]

    @cached_property
    def ip6_set_full_info(self):
        if self.prefix_v6:
            return {
                'network' : str(self.prefix_v6),
                'netmask' : 'ffff:ffff:ffff:ffff::',
                'netmask_cidr' : str(self.prefix_v6_length),
                'vlan': str(self.vlan),
                'vlan_id': str(self.vlan.vlan_id)
            }
        else:
            return None

    @cached_property
    def ip_network(self):
        """Renvoie le network parent du range start-stop, si spécifié
        Différent de ip_set_cidrs ou iP_set, car lui est supérieur ou égal"""
        if self.domaine_ip_network:
            return IPNetwork(str(self.domaine_ip_network) + '/' + str(self.domaine_ip_netmask))
        return None

    @cached_property
    def ip_net_full_info(self):
        """Renvoie les infos du network contenant du range"""
        return {
            'network' : str(self.ip_network.network),
            'netmask' : str(self.ip_network.netmask),
            'broadcast' : str(self.ip_network.broadcast),
            'netmask_cidr' : str(self.ip_network.prefixlen),
        }

    @cached_property
    def complete_prefixv6(self):
        """Return the complete prefix v6 as cidr"""
        return str(self.prefix_v6) + "/" + str(self.prefix_v6_length)

    def ip_objects(self):
        """ Renvoie tous les objets ipv4 relié à ce type"""
        return IpList.objects.filter(ip_type=self)

    def free_ip(self):
        """ Renvoie toutes les ip libres associées au type donné (self)"""
        return IpList.objects.filter(
            interface__isnull=True
        ).filter(ip_type=self)

    def gen_ip_range(self):
        """ Cree les IpList associées au type self. Parcours pédestrement et
        crée les ip une par une. Si elles existent déjà, met à jour le type
        associé à l'ip"""
        # Creation du range d'ip dans les objets iplist
        ip_obj = [IpList(ip_type=self, ipv4=str(ip)) for ip in self.ip_range]
        listes_ip = IpList.objects.filter(
            ipv4__in=[str(ip) for ip in self.ip_range]
        )
        # Si il n'y a pas d'ip, on les crée
        if not listes_ip:
            IpList.objects.bulk_create(ip_obj)
        # Sinon on update l'ip_type
        else:
            listes_ip.update(ip_type=self)
        return

    def del_ip_range(self):
        """ Methode dépréciée, IpList est en mode cascade et supprimé
        automatiquement"""
        if Interface.objects.filter(ipv4__in=self.ip_objects()):
            raise ValidationError(_("One or several IP addresses from the"
                                    " range are affected, impossible to delete"
                                    " the range."))
        for ip in self.ip_objects():
            ip.delete()

    def check_replace_prefixv6(self):
        """Remplace les prefixv6 des interfaces liées à ce type d'ip"""
        if not self.prefix_v6:
            return
        else:
            for ipv6 in Ipv6List.objects.filter(
                interface__in=Interface.objects.filter(
                    type__in=MachineType.objects.filter(ip_type=self)
                )
            ):
                ipv6.check_and_replace_prefix(prefix=self.prefix_v6)

    def get_associated_ptr_records(self):
        from re2o.utils import all_active_assigned_interfaces
        if self.reverse_v4:
            return (all_active_assigned_interfaces()
                    .filter(type__ip_type=self)
                    .filter(ipv4__isnull=False))
        else:
            return None

    def get_associated_ptr_v6_records(self):
        from re2o.utils import all_active_interfaces
        if self.reverse_v6:
            return (all_active_interfaces(full=True)
                    .filter(type__ip_type=self))
        else:
            return None

    def clean(self):
        """ Nettoyage. Vérifie :
        - Que ip_stop est après ip_start
        - Qu'on ne crée pas plus gros qu'un /16
        - Que le range crée ne recoupe pas un range existant
        - Formate l'ipv6 donnée en /64"""
        if IPAddress(self.domaine_ip_start) > IPAddress(self.domaine_ip_stop):
            raise ValidationError(_("Range end must be after range start..."))
        # On ne crée pas plus grand qu'un /16
        if self.ip_range.size > 65536:
            raise ValidationError(_("The range is too large, you can't create"
                                    " a larger one than a /16."))
        # On check que les / ne se recoupent pas
        for element in IpType.objects.all().exclude(pk=self.pk):
            if not self.ip_set.isdisjoint(element.ip_set):
                raise ValidationError(_("The specified range is not disjoint"
                                        " from existing ranges."))
        # On formate le prefix v6
        if self.prefix_v6:
            self.prefix_v6 = str(IPNetwork(self.prefix_v6 + '/64').network)
        # On vérifie qu'un domaine network/netmask contiens bien le domaine ip start-stop
        if self.domaine_ip_network:
            if not self.domaine_ip_start in self.ip_network or not self.domaine_ip_stop in self.ip_network:
                raise ValidationError(_("If you specify a domain network or"
                                        " netmask, it must contain the"
                                        " domain's IP range."))
        return

    def save(self, *args, **kwargs):
        self.clean()
        super(IpType, self).save(*args, **kwargs)

    @staticmethod
    def can_use_all(user_request, *_args, **_kwargs):
        """Superdroit qui permet d'utiliser toutes les extensions sans
        restrictions
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        return user_request.has_perm('machines.use_all_iptype'), None

    def __str__(self):
        return self.type


class Vlan(RevMixin, AclMixin, models.Model):
    """ Un vlan : vlan_id et nom
    On limite le vlan id entre 0 et 4096, comme défini par la norme"""
    vlan_id = models.PositiveIntegerField(validators=[MaxValueValidator(4095)])
    name = models.CharField(max_length=256)
    comment = models.CharField(max_length=256, blank=True)
    #Réglages supplémentaires
    arp_protect = models.BooleanField(default=False)
    dhcp_snooping = models.BooleanField(default=False)
    dhcpv6_snooping = models.BooleanField(default=False)
    igmp = models.BooleanField(
        default=False,
        help_text="Gestion multicast v4"
    )
    mld = models.BooleanField(
        default=False,
        help_text="Gestion multicast v6"
    )

    class Meta:
        permissions = (
            ("view_vlan", _("Can view a VLAN object")),
        )
        verbose_name = _("VLAN")
        verbose_name_plural = _("VLANs")

    def __str__(self):
        return self.name


class Nas(RevMixin, AclMixin, models.Model):
    """ Les nas. Associé à un machine_type.
    Permet aussi de régler le port_access_mode (802.1X ou mac-address) pour
    le radius. Champ autocapture de la mac à true ou false"""
    default_mode = '802.1X'
    AUTH = (
        ('802.1X', '802.1X'),
        ('Mac-address', 'Mac-address'),
    )

    name = models.CharField(max_length=255, unique=True)
    nas_type = models.ForeignKey(
        'MachineType',
        on_delete=models.PROTECT,
        related_name='nas_type'
    )
    machine_type = models.ForeignKey(
        'MachineType',
        on_delete=models.PROTECT,
        related_name='machinetype_on_nas'
    )
    port_access_mode = models.CharField(
        choices=AUTH,
        default=default_mode,
        max_length=32
    )
    autocapture_mac = models.BooleanField(default=False)

    class Meta:
        permissions = (
            ("view_nas", _("Can view a NAS device object")),
        )
        verbose_name = _("NAS device")
        verbose_name_plural = _("NAS devices")

    def __str__(self):
        return self.name


class SOA(RevMixin, AclMixin, models.Model):
    """
    Un enregistrement SOA associé à une extension
    Les valeurs par défault viennent des recommandations RIPE :
    https://www.ripe.net/publications/docs/ripe-203
    """
    name = models.CharField(max_length=255)
    mail = models.EmailField(
        help_text=_("Contact email address for the zone")
    )
    refresh = models.PositiveIntegerField(
        default=86400,  # 24 hours
        help_text=_("Seconds before the secondary DNS have to ask the primary"
                    " DNS serial to detect a modification")
    )
    retry = models.PositiveIntegerField(
        default=7200,  # 2 hours
        help_text=_("Seconds before the secondary DNS ask the serial again in"
                    " case of a primary DNS timeout")
    )
    expire = models.PositiveIntegerField(
        default=3600000,  # 1000 hours
        help_text=_("Seconds before the secondary DNS stop answering requests"
                    " in case of primary DNS timeout")
    )
    ttl = models.PositiveIntegerField(
        default=172800,  # 2 days
        help_text=_("Time to Live")
    )

    class Meta:
        permissions = (
            ("view_soa", _("Can view an SOA record object")),
        )
        verbose_name = _("SOA record")
        verbose_name_plural = _("SOA records")

    def __str__(self):
        return str(self.name)

    @cached_property
    def dns_soa_param(self):
        """
        Renvoie la partie de l'enregistrement SOA correspondant aux champs :
            <refresh>   ; refresh
            <retry>     ; retry
            <expire>    ; expire
            <ttl>       ; TTL
        """
        return (
            '    {refresh}; refresh\n'
            '    {retry}; retry\n'
            '    {expire}; expire\n'
            '    {ttl}; TTL'
        ).format(
            refresh=str(self.refresh).ljust(12),
            retry=str(self.retry).ljust(12),
            expire=str(self.expire).ljust(12),
            ttl=str(self.ttl).ljust(12)
        )

    @cached_property
    def dns_soa_mail(self):
        """ Renvoie le mail dans l'enregistrement SOA """
        mail_fields = str(self.mail).split('@')
        return mail_fields[0].replace('.', '\\.') + '.' + mail_fields[1] + '.'

    @classmethod
    def new_default_soa(cls):
        """ Fonction pour créer un SOA par défaut, utile pour les nouvelles
        extensions .
        /!\ Ne jamais supprimer ou renommer cette fonction car elle est
        utilisée dans les migrations de la BDD. """
        return cls.objects.get_or_create(
            name=_("SOA to edit"),
            mail="postmaser@example.com"
        )[0].pk


class Extension(RevMixin, AclMixin, models.Model):
    """ Extension dns type example.org. Précise si tout le monde peut
    l'utiliser, associé à un origin (ip d'origine)"""
    name = models.CharField(
        max_length=255,
        unique=True,
        help_text=_("Zone name, must begin with a dot (.example.org)")
    )
    need_infra = models.BooleanField(default=False)
    origin = models.ForeignKey(
        'IpList',
        on_delete=models.PROTECT,
        blank=True,
        null=True,
        help_text=_("A record associated with the zone")
    )
    origin_v6 = models.GenericIPAddressField(
        protocol='IPv6',
        null=True,
        blank=True,
        help_text=_("AAAA record associated with the zone")
    )
    soa = models.ForeignKey(
        'SOA',
        on_delete=models.CASCADE
    )

    class Meta:
        permissions = (
            ("view_extension", _("Can view an extension object")),
            ("use_all_extension", _("Can use all extensions")),
        )
        verbose_name = _("DNS extension")
        verbose_name_plural = _("DNS extensions")

    @cached_property
    def dns_entry(self):
        """ Une entrée DNS A et AAAA sur origin (zone self)"""
        entry = ""
        if self.origin:
            entry += "@               IN  A       " + str(self.origin)
        if self.origin_v6:
            if entry:
                entry += "\n"
            entry += "@               IN  AAAA    " + str(self.origin_v6)
        return entry

    def get_associated_sshfp_records(self):
        from re2o.utils import all_active_assigned_interfaces
        return (all_active_assigned_interfaces()
                .filter(type__ip_type__extension=self)
                .filter(machine__id__in=SshFp.objects.values('machine')))

    def get_associated_a_records(self):
        from re2o.utils import all_active_assigned_interfaces
        return (all_active_assigned_interfaces()
                .filter(type__ip_type__extension=self)
                .filter(ipv4__isnull=False))

    def get_associated_aaaa_records(self):
        from re2o.utils import all_active_interfaces
        return (all_active_interfaces(full=True)
                .filter(type__ip_type__extension=self))

    def get_associated_cname_records(self):
        from re2o.utils import all_active_assigned_interfaces
        return (Domain.objects
                .filter(extension=self)
                .filter(cname__interface_parent__in=all_active_assigned_interfaces())
                .prefetch_related('cname'))

    @staticmethod
    def can_use_all(user_request, *_args, **_kwargs):
        """Superdroit qui permet d'utiliser toutes les extensions sans
        restrictions
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        return user_request.has_perm('machines.use_all_extension'), None

    def __str__(self):
        return self.name

    def clean(self, *args, **kwargs):
        if self.name and self.name[0] != '.':
            raise ValidationError(_("An extension must begin with a dot."))
        super(Extension, self).clean(*args, **kwargs)


class Mx(RevMixin, AclMixin, models.Model):
    """ Entrées des MX. Enregistre la zone (extension) associée et la
    priorité
    Todo : pouvoir associer un MX à une interface """
    zone = models.ForeignKey('Extension', on_delete=models.PROTECT)
    priority = models.PositiveIntegerField()
    name = models.ForeignKey('Domain', on_delete=models.PROTECT)

    class Meta:
        permissions = (
            ("view_mx", _("Can view an MX record object")),
        )
        verbose_name = _("MX record")
        verbose_name_plural = _("MX records")

    @cached_property
    def dns_entry(self):
        """Renvoie l'entrée DNS complète pour un MX à mettre dans les
        fichiers de zones"""
        return "@               IN  MX  {prior} {name}".format(
            prior=str(self.priority).ljust(3),
            name=str(self.name)
        )

    def __str__(self):
        return str(self.zone) + ' ' + str(self.priority) + ' ' + str(self.name)


class Ns(RevMixin, AclMixin, models.Model):
    """Liste des enregistrements name servers par zone considéérée"""
    zone = models.ForeignKey('Extension', on_delete=models.PROTECT)
    ns = models.ForeignKey('Domain', on_delete=models.PROTECT)

    class Meta:
        permissions = (
            ("view_ns", _("Can view an NS record object")),
        )
        verbose_name = _("NS record")
        verbose_name_plural = _("NS records")

    @cached_property
    def dns_entry(self):
        """Renvoie un enregistrement NS complet pour les filezones"""
        return "@               IN  NS      " + str(self.ns)

    def __str__(self):
        return str(self.zone) + ' ' + str(self.ns)


class Txt(RevMixin, AclMixin, models.Model):
    """ Un enregistrement TXT associé à une extension"""
    zone = models.ForeignKey('Extension', on_delete=models.PROTECT)
    field1 = models.CharField(max_length=255)
    field2 = models.TextField(max_length=2047)

    class Meta:
        permissions = (
            ("view_txt", _("Can view a TXT record object")),
        )
        verbose_name = _("TXT record")
        verbose_name_plural = _("TXT records")

    def __str__(self):
        return str(self.zone) + " : " + str(self.field1) + " " +\
            str(self.field2)

    @cached_property
    def dns_entry(self):
        """Renvoie l'enregistrement TXT complet pour le fichier de zone"""
        return str(self.field1).ljust(15) + " IN  TXT     " + str(self.field2)


class DName(RevMixin, AclMixin, models.Model):
    """A DNAME entry for the DNS."""
    zone = models.ForeignKey('Extension', on_delete=models.PROTECT)
    alias = models.CharField(max_length=255)

    class Meta:
        permissions = (
            ("view_dname", _("Can view a DNAME record object")),
        )
        verbose_name = _("DNAME record")
        verbose_name_plural = _("DNAME records")

    def __str__(self):
        return str(self.zone) + " : " + str(self.alias)

    @cached_property
    def dns_entry(self):
        """Returns the DNAME record for the DNS zone file."""
        return str(self.alias).ljust(15) + " IN  DNAME   " + str(self.zone)


class Srv(RevMixin, AclMixin, models.Model):
    """ A SRV record """
    TCP = 'TCP'
    UDP = 'UDP'

    service = models.CharField(max_length=31)
    protocole = models.CharField(
        max_length=3,
        choices=(
            (TCP, 'TCP'),
            (UDP, 'UDP'),
        ),
        default=TCP,
    )
    extension = models.ForeignKey('Extension', on_delete=models.PROTECT)
    ttl = models.PositiveIntegerField(
        default=172800,  # 2 days
        help_text=_("Time to Live")
    )
    priority = models.PositiveIntegerField(
        default=0,
        validators=[MaxValueValidator(65535)],
        help_text=_("Priority of the target server (positive integer value,"
                    " the lower it is, the more the server will be used if"
                    " available)")
    )
    weight = models.PositiveIntegerField(
        default=0,
        validators=[MaxValueValidator(65535)],
        help_text=_("Relative weight for records with the same priority"
                     " (integer value between 0 and 65535)")
    )
    port = models.PositiveIntegerField(
        validators=[MaxValueValidator(65535)],
        help_text=_("TCP/UDP port")
    )
    target = models.ForeignKey(
        'Domain',
        on_delete=models.PROTECT,
        help_text=_("Target server")
    )

    class Meta:
        permissions = (
            ("view_srv", _("Can view an SRV record object")),
        )
        verbose_name = _("SRV record")
        verbose_name_plural = _("SRV records")

    def __str__(self):
        return str(self.service) + ' ' + str(self.protocole) + ' ' +\
            str(self.extension) + ' ' + str(self.priority) +\
            ' ' + str(self.weight) + str(self.port) + str(self.target)

    @cached_property
    def dns_entry(self):
        """Renvoie l'enregistrement SRV complet pour le fichier de zone"""
        return str(self.service) + '._' + str(self.protocole).lower() +\
            str(self.extension) + '. ' + str(self.ttl) + ' IN SRV ' +\
            str(self.priority) + ' ' + str(self.weight) + ' ' +\
            str(self.port) + ' ' + str(self.target) + '.'


class SshFp(RevMixin, AclMixin, models.Model):
    """A fingerprint of an SSH public key"""

    ALGO = (
        ("ssh-rsa", "ssh-rsa"),
        ("ssh-ed25519", "ssh-ed25519"),
        ("ecdsa-sha2-nistp256", "ecdsa-sha2-nistp256"),
        ("ecdsa-sha2-nistp384", "ecdsa-sha2-nistp384"),
        ("ecdsa-sha2-nistp521", "ecdsa-sha2-nistp521"),
    )

    machine = models.ForeignKey('Machine', on_delete=models.CASCADE)
    pub_key_entry = models.TextField(
        help_text="SSH public key",
        max_length=2048
    )
    algo = models.CharField(
        choices=ALGO,
        max_length=32
    )
    comment = models.CharField(
        help_text="Comment",
        max_length=255,
        null=True,
        blank=True
    )

    @cached_property
    def algo_id(self):
        """Return the id of the algorithm for this key"""
        if "ecdsa" in self.algo:
            return 3
        elif "rsa" in self.algo:
            return 1
        else:
            return 2

    @cached_property
    def hash(self):
        """Return the hashess for the pub key with correct id
        cf RFC, 1 is sha1 , 2 sha256"""
        return {
            "1" : hashlib.sha1(base64.b64decode(self.pub_key_entry)).hexdigest(),
            "2" : hashlib.sha256(base64.b64decode(self.pub_key_entry)).hexdigest(),
        }

    class Meta:
        permissions = (
            ("view_sshfp", _("Can view an SSHFP record object")),
        )
        verbose_name = _("SSHFP record")
        verbose_name_plural = _("SSHFP records")

    def can_view(self, user_request, *_args, **_kwargs):
        return self.machine.can_view(user_request, *_args, **_kwargs)

    def can_edit(self, user_request, *args, **kwargs):
        return self.machine.can_edit(user_request, *args, **kwargs)

    def can_delete(self, user_request, *args, **kwargs):
        return self.machine.can_delete(user_request, *args, **kwargs)

    def __str__(self):
        return str(self.algo) + ' ' + str(self.comment)



class Interface(RevMixin, AclMixin, FieldPermissionModelMixin, models.Model):
    """ Une interface. Objet clef de l'application machine :
    - une address mac unique. Possibilité de la rendre unique avec le
    typemachine
    - une onetoone vers IpList pour attribution ipv4
    - le type parent associé au range ip et à l'extension
    - un objet domain associé contenant son nom
    - la liste des ports oiuvert"""
    ipv4 = models.OneToOneField(
        'IpList',
        on_delete=models.PROTECT,
        blank=True,
        null=True
    )
    mac_address = MACAddressField(integer=False)
    machine = models.ForeignKey('Machine', on_delete=models.CASCADE)
    type = models.ForeignKey('MachineType', on_delete=models.PROTECT)
    details = models.CharField(max_length=255, blank=True)
    port_lists = models.ManyToManyField('OuverturePortList', blank=True)

    class Meta:
        permissions = (
            ("view_interface", _("Can view an interface object")),
            ("change_interface_machine",
             _("Can change the owner of an interface")),
        )
        verbose_name = _("interface")
        verbose_name_plural = _("interfaces")

    @cached_property
    def is_active(self):
        """ Renvoie si une interface doit avoir accès ou non """
        machine = self.machine
        user = self.machine.user
        return machine.active and user.has_access()

    @cached_property
    def ipv6_slaac(self):
        """ Renvoie un objet type ipv6 à partir du prefix associé à
        l'iptype parent"""
        if self.type.ip_type.prefix_v6:
            return EUI(self.mac_address).ipv6(
                IPNetwork(self.type.ip_type.prefix_v6).network
            )
        else:
            return None

    @cached_property
    def gen_ipv6_dhcpv6(self):
        """Cree une ip, à assigner avec dhcpv6 sur une machine"""
        prefix_v6 = self.type.ip_type.prefix_v6.encode().decode('utf-8')
        if not prefix_v6:
            return None
        return IPv6Address(
            IPv6Address(prefix_v6).exploded[:20] +
            IPv6Address(self.id).exploded[20:]
        )

    def sync_ipv6_dhcpv6(self):
        """Affecte une ipv6 dhcpv6 calculée à partir de l'id de la machine"""
        ipv6_dhcpv6 = self.gen_ipv6_dhcpv6
        if not ipv6_dhcpv6:
            return
        ipv6 = Ipv6List.objects.filter(ipv6=str(ipv6_dhcpv6)).first()
        if not ipv6:
            ipv6 = Ipv6List(ipv6=str(ipv6_dhcpv6))
        ipv6.interface = self
        ipv6.save()
        return

    def sync_ipv6_slaac(self):
        """Cree, mets à jour et supprime si il y a lieu l'ipv6 slaac associée
        à la machine
        Sans prefixe ipv6, on return
        Si l'ip slaac n'est pas celle qu'elle devrait être, on maj"""
        ipv6_slaac = self.ipv6_slaac
        if not ipv6_slaac:
            return
        ipv6_object = (Ipv6List.objects
                       .filter(interface=self, slaac_ip=True)
                       .first())
        if not ipv6_object:
            ipv6_object = Ipv6List(interface=self, slaac_ip=True)
        if ipv6_object.ipv6 != str(ipv6_slaac):
            ipv6_object.ipv6 = str(ipv6_slaac)
            ipv6_object.save()

    def sync_ipv6(self):
        """Cree et met à jour l'ensemble des ipv6 en fonction du mode choisi"""
        if (preferences.models.OptionalMachine
                .get_cached_value('ipv6_mode') == 'SLAAC'):
            self.sync_ipv6_slaac()
        elif (preferences.models.OptionalMachine
              .get_cached_value('ipv6_mode') == 'DHCPV6'):
            self.sync_ipv6_dhcpv6()
        else:
            return

    def ipv6(self):
        """ Renvoie le queryset de la liste des ipv6
        On renvoie l'ipv6 slaac que si le mode slaac est activé
        (et non dhcpv6)"""
        if (preferences.models.OptionalMachine
                .get_cached_value('ipv6_mode') == 'SLAAC'):
            return self.ipv6list.all()
        elif (preferences.models.OptionalMachine
              .get_cached_value('ipv6_mode') == 'DHCPV6'):
            return self.ipv6list.filter(slaac_ip=False)
        else:
            return None

    def mac_bare(self):
        """ Formatage de la mac type mac_bare"""
        return str(EUI(self.mac_address, dialect=mac_bare)).lower()

    def filter_macaddress(self):
        """ Tente un formatage mac_bare, si échoue, lève une erreur de
        validation"""
        try:
            self.mac_address = str(EUI(self.mac_address))
        except:
            raise ValidationError(_("The given MAC address is invalid."))

    def clean(self, *args, **kwargs):
        """ Formate l'addresse mac en mac_bare (fonction filter_mac)
        et assigne une ipv4 dans le bon range si inexistante ou incohérente"""
        # If type was an invalid value, django won't create an attribute type
        # but try clean() as we may be able to create it from another value
        # so even if the error as yet been detected at this point, django
        # continues because the error might not prevent us from creating the
        # instance.
        # But in our case, it's impossible to create a type value so we raise
        # the error.
        if not hasattr(self, 'type'):
            raise ValidationError(_("The selected IP type is invalid."))
        self.filter_macaddress()
        self.mac_address = str(EUI(self.mac_address)) or None
        if not self.ipv4 or self.type.ip_type != self.ipv4.ip_type:
            self.assign_ipv4()
        super(Interface, self).clean(*args, **kwargs)

    def assign_ipv4(self):
        """ Assigne une ip à l'interface """
        free_ips = self.type.ip_type.free_ip()
        if free_ips:
            self.ipv4 = free_ips[0]
        else:
            raise ValidationError(_("There is no IP address available in the"
                                    " slash."))
        return

    def unassign_ipv4(self):
        """ Sans commentaire, désassigne une ipv4"""
        self.ipv4 = None

    def update_type(self):
        """ Lorsque le machinetype est changé de type d'ip, on réassigne"""
        self.clean()
        self.save()

    def save(self, *args, **kwargs):
        self.filter_macaddress()
        # On verifie la cohérence en forçant l'extension par la méthode
        if self.ipv4:
            if self.type.ip_type != self.ipv4.ip_type:
                raise ValidationError(_("The IPv4 address and the machine type"
                                        " don't match."))
        super(Interface, self).save(*args, **kwargs)

    @staticmethod
    def can_create(user_request, machineid, *_args, **_kwargs):
        """Verifie que l'user a les bons droits infra pour créer
        une interface, ou bien que la machine appartient bien à l'user
        :param macineid: Id de la machine parente de l'interface
        :param user_request: instance utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        try:
            machine = Machine.objects.get(pk=machineid)
        except Machine.DoesNotExist:
            return False, _("Nonexistent machine.")
        if not user_request.has_perm('machines.add_interface'):
            if not (preferences.models.OptionalMachine
                    .get_cached_value('create_machine')):
                return False, _("You can't add a machine.")
            max_lambdauser_interfaces = (preferences.models.OptionalMachine
                                         .get_cached_value(
                                             'max_lambdauser_interfaces'
                                         ))
            if machine.user != user_request:
                return False, _("You don't have the right to add an interface"
                                " to a machine of another user.")
            if (machine.user.user_interfaces().count() >=
                    max_lambdauser_interfaces):
                return False, (_("You reached the maximum number of interfaces"
                                 " that you are allowed to create yourself"
                                 " (%s)." % max_lambdauser_interfaces))
        return True, None

    @staticmethod
    def can_change_machine(user_request, *_args, **_kwargs):
        """Check if a user can change the machine associated with an
        Interface object """
        return (user_request.has_perm('machines.change_interface_machine'),
                _("Permission required to edit the machine."))

    def can_edit(self, user_request, *args, **kwargs):
        """Verifie que l'user a les bons droits infra pour editer
        cette instance interface, ou qu'elle lui appartient
        :param self: Instance interface à editer
        :param user_request: Utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        if self.machine.user != user_request:
            if (not user_request.has_perm('machines.change_interface') or
                    not self.machine.user.can_edit(
                        user_request,
                        *args,
                        **kwargs
                    )[0]):
                return False, _("You don't have the right to edit a machine of"
                                " another user.")
        return True, None

    def can_delete(self, user_request, *args, **kwargs):
        """Verifie que l'user a les bons droits delete object pour del
        cette instance interface, ou qu'elle lui appartient
        :param self: Instance interface à del
        :param user_request: Utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        if self.machine.user != user_request:
            if (not user_request.has_perm('machines.change_interface') or
                    not self.machine.user.can_edit(
                        user_request,
                        *args,
                        **kwargs
                    )[0]):
                return False, _("You don't have the right to edit a machine of"
                                " another user.")
        return True, None

    def can_view(self, user_request, *_args, **_kwargs):
        """Vérifie qu'on peut bien voir cette instance particulière avec
        droit view objet ou qu'elle appartient à l'user
        :param self: instance interface à voir
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        if (not user_request.has_perm('machines.view_interface') and
                self.machine.user != user_request):
            return False, _("You don't have the right to view machines other"
                            " than yours.")
        return True, None

    def __init__(self, *args, **kwargs):
        super(Interface, self).__init__(*args, **kwargs)
        self.field_permissions = {
            'machine': self.can_change_machine,
        }

    def __str__(self):
        try:
            domain = self.domain
        except:
            domain = None
        return str(domain)

    def has_private_ip(self):
        """ True si l'ip associée est privée"""
        if self.ipv4:
            return IPAddress(str(self.ipv4)).is_private()
        else:
            return False

    def may_have_port_open(self):
        """ True si l'interface a une ip et une ip publique.
        Permet de ne pas exporter des ouvertures sur des ip privées
        (useless)"""
        return self.ipv4 and not self.has_private_ip()


class Ipv6List(RevMixin, AclMixin, FieldPermissionModelMixin, models.Model):
    """ A list of IPv6 """

    ipv6 = models.GenericIPAddressField(
        protocol='IPv6',
    )
    interface = models.ForeignKey(
        'Interface',
        on_delete=models.CASCADE,
        related_name='ipv6list'
    )
    slaac_ip = models.BooleanField(default=False)

    class Meta:
        permissions = (
            ("view_ipv6list", _("Can view an IPv6 addresses list object")),
            ("change_ipv6list_slaac_ip", _("Can change the SLAAC value of an"
                                           " IPv6 addresses list")),
        )
        verbose_name = _("IPv6 addresses list")
        verbose_name_plural = _("IPv6 addresses lists")

    @staticmethod
    def can_create(user_request, interfaceid, *_args, **_kwargs):
        """Verifie que l'user a les bons droits infra pour créer
        une ipv6, ou possède l'interface associée
        :param interfaceid: Id de l'interface associée à cet objet domain
        :param user_request: instance utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        try:
            interface = Interface.objects.get(pk=interfaceid)
        except Interface.DoesNotExist:
            return False, _("Nonexistent interface.")
        if not user_request.has_perm('machines.add_ipv6list'):
            if interface.machine.user != user_request:
                return False, _("You don't have the right to add an alias to a"
                                " machine of another user.")
        return True, None

    @staticmethod
    def can_change_slaac_ip(user_request, *_args, **_kwargs):
        """ Check if a user can change the slaac value """
        return (user_request.has_perm('machines.change_ipv6list_slaac_ip'),
                _("Permission required to change the SLAAC value of an IPv6"
                  " address"))

    def can_edit(self, user_request, *args, **kwargs):
        """Verifie que l'user a les bons droits infra pour editer
        cette instance interface, ou qu'elle lui appartient
        :param self: Instance interface à editer
        :param user_request: Utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        if self.interface.machine.user != user_request:
            if (not user_request.has_perm('machines.change_ipv6list') or
                    not self.interface.machine.user.can_edit(
                        user_request,
                        *args,
                        **kwargs
                    )[0]):
                return False, _("You don't have the right to edit a machine of"
                                " another user.")
        return True, None

    def can_delete(self, user_request, *args, **kwargs):
        """Verifie que l'user a les bons droits delete object pour del
        cette instance interface, ou qu'elle lui appartient
        :param self: Instance interface à del
        :param user_request: Utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        if self.interface.machine.user != user_request:
            if (not user_request.has_perm('machines.change_ipv6list') or
                    not self.interface.machine.user.can_edit(
                        user_request,
                        *args,
                        **kwargs
                    )[0]):
                return False, _("You don't have the right to edit a machine of"
                                " another user.")
        return True, None

    def can_view(self, user_request, *_args, **_kwargs):
        """Vérifie qu'on peut bien voir cette instance particulière avec
        droit view objet ou qu'elle appartient à l'user
        :param self: instance interface à voir
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        if (not user_request.has_perm('machines.view_ipv6list') and
                self.interface.machine.user != user_request):
            return False, _("You don't have the right to view machines other"
                            " than yours.")
        return True, None

    def __init__(self, *args, **kwargs):
        super(Ipv6List, self).__init__(*args, **kwargs)
        self.field_permissions = {
            'slaac_ip': self.can_change_slaac_ip,
        }

    def check_and_replace_prefix(self, prefix=None):
        """Si le prefixe v6 est incorrect, on maj l'ipv6"""
        prefix_v6 = prefix or self.interface.type.ip_type.prefix_v6.encode().decode('utf-8')
        if not prefix_v6:
            return
        if (IPv6Address(self.ipv6.encode().decode('utf-8')).exploded[:20] !=
                IPv6Address(prefix_v6).exploded[:20]):
            self.ipv6 = IPv6Address(
                IPv6Address(prefix_v6).exploded[:20] +
                IPv6Address(self.ipv6.encode().decode('utf-8')).exploded[20:]
            )
            self.save()

    def clean(self, *args, **kwargs):
        if self.slaac_ip and (Ipv6List.objects
                              .filter(interface=self.interface, slaac_ip=True)
                              .exclude(id=self.id)):
            raise ValidationError(_("A SLAAC IP address is already registered."))
        prefix_v6 = self.interface.type.ip_type.prefix_v6.encode().decode('utf-8')
        if prefix_v6:
            if (IPv6Address(self.ipv6.encode().decode('utf-8')).exploded[:20] !=
                    IPv6Address(prefix_v6).exploded[:20]):
                raise ValidationError(_("The v6 prefix is incorrect and"
                                        " doesn't match the type associated"
                                        " with the machine."))
        super(Ipv6List, self).clean(*args, **kwargs)

    def save(self, *args, **kwargs):
        """Force à avoir appellé clean avant"""
        self.full_clean()
        super(Ipv6List, self).save(*args, **kwargs)

    def __str__(self):
        return str(self.ipv6)


class Domain(RevMixin, AclMixin, models.Model):
    """ Objet domain. Enregistrement A et CNAME en même temps : permet de
    stocker les alias et les nom de machines, suivant si interface_parent
    ou cname sont remplis"""

    interface_parent = models.OneToOneField(
        'Interface',
        on_delete=models.CASCADE,
        blank=True,
        null=True
    )
    name = models.CharField(
        help_text=_("Mandatory and unique, must not contain dots."),
        max_length=255
    )
    extension = models.ForeignKey('Extension', on_delete=models.PROTECT)
    cname = models.ForeignKey(
        'self',
        null=True,
        blank=True,
        related_name='related_domain'
    )

    class Meta:
        unique_together = (("name", "extension"),)
        permissions = (
            ("view_domain", _("Can view a domain object")),
        )
        verbose_name = _("domain")
        verbose_name_plural = _("domains")

    def get_extension(self):
        """ Retourne l'extension de l'interface parente si c'est un A
         Retourne l'extension propre si c'est un cname, renvoie None sinon"""
        if self.interface_parent:
            return self.interface_parent.type.ip_type.extension
        elif hasattr(self, 'extension'):
            return self.extension
        else:
            return None

    def clean(self):
        """ Validation :
        - l'objet est bien soit A soit CNAME
        - le cname est pas pointé sur lui-même
        - le nom contient bien les caractères autorisés par la norme
        dns et moins de 63 caractères au total
        - le couple nom/extension est bien unique"""
        if self.get_extension():
            self.extension = self.get_extension()
        if self.interface_parent and self.cname:
            raise ValidationError(_("You can't create a both A and CNAME"
                                    " record."))
        if self.cname == self:
            raise ValidationError(_("You can't create a CNAME record pointing"
                                    " to itself."))
        HOSTNAME_LABEL_PATTERN = re.compile(
            r"(?!-)[A-Z\d-]+(?<!-)$",
            re.IGNORECASE
        )
        dns = self.name.lower()
        if len(dns) > 63:
            raise ValidationError(_("The domain name %s is too long (over 63"
                                    " characters).") % dns)
        if not HOSTNAME_LABEL_PATTERN.match(dns):
            raise ValidationError(_("The domain name %s contains forbidden"
                                    " characters.") % dns)
        self.validate_unique()
        super(Domain, self).clean()

    @cached_property
    def dns_entry(self):
        """ Une entrée DNS"""
        if self.cname:
            return "{name} IN CNAME   {cname}.".format(
                name=str(self.name).ljust(15),
                cname=str(self.cname)
            )

    def save(self, *args, **kwargs):
        """ Empèche le save sans extension valide.
        Force à avoir appellé clean avant"""
        if not self.get_extension():
            raise ValidationError(_("Invalid extension."))
        self.full_clean()
        super(Domain, self).save(*args, **kwargs)

    @cached_property
    def get_source_interface(self):
        """Renvoie l'interface source :
        - l'interface reliée si c'est un A
        - si c'est un cname, suit le cname jusqu'à atteindre le A
        et renvoie l'interface parente
        Fonction récursive"""
        if self.interface_parent:
            return self.interface_parent
        else:
            return self.cname.get_parent_interface()

    @staticmethod
    def can_create(user_request, interfaceid, *_args, **_kwargs):
        """Verifie que l'user a les bons droits infra pour créer
        un domain, ou possède l'interface associée
        :param interfaceid: Id de l'interface associée à cet objet domain
        :param user_request: instance utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        try:
            interface = Interface.objects.get(pk=interfaceid)
        except Interface.DoesNotExist:
            return False, _("Nonexistent interface.")
        if not user_request.has_perm('machines.add_domain'):
            max_lambdauser_aliases = (preferences.models.OptionalMachine
                                      .get_cached_value(
                                          'max_lambdauser_aliases'
                                      ))
            if interface.machine.user != user_request:
                return False, _("You don't have the right to add an alias to a"
                                " machine of another user.")
            if Domain.objects.filter(
                    cname__in=Domain.objects.filter(
                        interface_parent__in=(interface.machine.user
                                              .user_interfaces())
                    )
                ).count() >= max_lambdauser_aliases:
                return False, _("You reached the maximum number of alias that"
                                " you are allowed to create yourself (%s). "
                                % max_lambdauser_aliases)
        return True, None

    def can_edit(self, user_request, *_args, **_kwargs):
        """Verifie que l'user a les bons droits pour editer
        cette instance domain
        :param self: Instance domain à editer
        :param user_request: Utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        if (not user_request.has_perm('machines.change_domain') and
                self.get_source_interface.machine.user != user_request):
            return False, _("You don't have the right to edit an alias of a"
                            " machine of another user.")
        return True, None

    def can_delete(self, user_request, *_args, **_kwargs):
        """Verifie que l'user a les bons droits delete object pour del
        cette instance domain, ou qu'elle lui appartient
        :param self: Instance domain à del
        :param user_request: Utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        if (not user_request.has_perm('machines.delete_domain') and
                self.get_source_interface.machine.user != user_request):
            return False, _("You don't have the right to delete an alias of a"
                            " machine of another user.")
        return True, None

    def can_view(self, user_request, *_args, **_kwargs):
        """Vérifie qu'on peut bien voir cette instance particulière avec
        droit view objet ou qu'elle appartient à l'user
        :param self: instance domain à voir
        :param user_request: instance user qui fait l'edition
        :return: True ou False avec la raison de l'échec le cas échéant"""
        if (not user_request.has_perm('machines.view_domain') and
                self.get_source_interface.machine.user != user_request):
            return False, _("You don't have the right to view machines other"
                            " than yours.")
        return True, None

    def __str__(self):
        return str(self.name) + str(self.extension)


class IpList(RevMixin, AclMixin, models.Model):
    """ A list of IPv4 """

    ipv4 = models.GenericIPAddressField(protocol='IPv4', unique=True)
    ip_type = models.ForeignKey('IpType', on_delete=models.CASCADE)

    class Meta:
        permissions = (
            ("view_iplist", _("Can view an IPv4 addresses list object")),
        )
        verbose_name = _("IPv4 addresses list")
        verbose_name_plural = _("IPv4 addresses lists")

    @cached_property
    def need_infra(self):
        """ Permet de savoir si un user basique peut assigner cette ip ou
        non"""
        return self.ip_type.need_infra

    def clean(self):
        """ Erreur si l'ip_type est incorrect"""
        if not str(self.ipv4) in self.ip_type.ip_set_as_str:
            raise ValidationError(_("The IPv4 address and the range of the IP"
                                    " type don't match."))
        return

    def save(self, *args, **kwargs):
        self.clean()
        super(IpList, self).save(*args, **kwargs)

    def __str__(self):
        return self.ipv4


class Role(RevMixin, AclMixin, models.Model):
    """Define the role of a machine.
    Allow automated generation of the server configuration.
    """

    ROLE = (
        ('dhcp-server', _("DHCP server")),
        ('switch-conf-server', _("Switches configuration server")),
        ('dns-recursif-server', _("Recursive DNS server")),
        ('ntp-server', _("NTP server")),
        ('radius-server', _("RADIUS server")),
        ('log-server', _("Log server")),
        ('ldap-master-server', _("LDAP master server")),
        ('ldap-backup-server', _("LDAP backup server")),
        ('smtp-server', _("SMTP server")),
        ('postgresql-server', _("postgreSQL server")),
        ('mysql-server', _("mySQL server")),
        ('sql-client', _("SQL client")),
        ('gateway', _("Gateway")),
    )

    role_type = models.CharField(max_length=255, unique=True)
    servers = models.ManyToManyField('Interface')
    specific_role = models.CharField(
        choices=ROLE,
        null=True,
        blank=True,
        max_length=32,
    )

    class Meta:
        permissions = (
            ("view_role", _("Can view a role object")),
        )
        verbose_name = _("server role")
        verbose_name_plural = _("server roles")

    @classmethod
    def get_instance(cls, roleid, *_args, **_kwargs):
        """Get the Role instance with roleid.

        Args:
            roleid: The id

        Returns:
            The role.
        """
        return cls.objects.get(pk=roleid)

    @classmethod
    def interface_for_roletype(cls, roletype):
        """Return interfaces for a roletype"""
        return Interface.objects.filter(
            role=cls.objects.filter(specific_role=roletype)
        )

    @classmethod
    def all_interfaces_for_roletype(cls, roletype):
        """Return all interfaces for a roletype"""
        return Interface.objects.filter(
            machine__interface__role=cls.objects.filter(specific_role=roletype)
        )

    @classmethod
    def get_instance(cls, machineid, *_args, **_kwargs):
        """Get the Machine instance with machineid.
        :param userid: The id
        :return: The user
        """
        return cls.objects.get(pk=machineid)

    @classmethod
    def interface_for_roletype(cls, roletype):
        """Return interfaces for a roletype"""
        return Interface.objects.filter(role=cls.objects.filter(specific_role=roletype))

    def save(self, *args, **kwargs):
        super(Role, self).save(*args, **kwargs)

    def __str__(self):
        return str(self.role_type)


class Service(RevMixin, AclMixin, models.Model):
    """ Definition d'un service (dhcp, dns, etc)"""

    service_type = models.CharField(max_length=255, blank=True, unique=True)
    min_time_regen = models.DurationField(
        default=timedelta(minutes=1),
        help_text=_("Minimal time before regeneration of the service.")
    )
    regular_time_regen = models.DurationField(
        default=timedelta(hours=1),
        help_text=_("Maximal time before regeneration of the service.")
    )
    servers = models.ManyToManyField('Interface', through='Service_link')

    class Meta:
        permissions = (
            ("view_service", _("Can view a service object")),
        )
        verbose_name = _("service to generate (DHCP, DNS, ...)")
        verbose_name_plural = _("services to generate (DHCP, DNS, ...)")

    def ask_regen(self):
        """ Marque à True la demande de régénération pour un service x """
        Service_link.objects.filter(service=self).exclude(asked_regen=True)\
            .update(asked_regen=True)
        return

    def process_link(self, servers):
        """ Django ne peut créer lui meme les relations manytomany avec table
        intermediaire explicite"""
        for serv in servers.exclude(
            pk__in=Interface.objects.filter(service=self)
        ):
            link = Service_link(service=self, server=serv)
            link.save()
        Service_link.objects.filter(service=self).exclude(server__in=servers)\
            .delete()
        return

    def save(self, *args, **kwargs):
        super(Service, self).save(*args, **kwargs)

    def __str__(self):
        return str(self.service_type)


def regen(service):
    """ Fonction externe pour régérération d'un service, prend un objet service
    en arg"""
    obj = Service.objects.filter(service_type=service)
    if obj:
        obj[0].ask_regen()
    return


class Service_link(RevMixin, AclMixin, models.Model):
    """ Definition du lien entre serveurs et services"""

    service = models.ForeignKey('Service', on_delete=models.CASCADE)
    server = models.ForeignKey('Interface', on_delete=models.CASCADE)
    last_regen = models.DateTimeField(auto_now_add=True)
    asked_regen = models.BooleanField(default=False)

    class Meta:
        permissions = (
            ("view_service_link", _("Can view a service server link object")),
        )
        verbose_name = _("link between service and server")
        verbose_name_plural = _("links between service and server")

    def done_regen(self):
        """ Appellé lorsqu'un serveur a regénéré son service"""
        self.last_regen = timezone.now()
        self.asked_regen = False
        self.save()

    @property
    def need_regen(self):
        """ Décide si le temps minimal écoulé est suffisant pour provoquer une
        régénération de service"""
        return bool(
            (self.asked_regen and (
                self.last_regen + self.service.min_time_regen
            ) < timezone.now()
            ) or (
                self.last_regen + self.service.regular_time_regen
            ) < timezone.now()
        )

    @need_regen.setter
    def need_regen(self, value):
        """
        Force to set the need_regen value. True means a regen is asked and False
        means a regen has been done.

        :param value: (bool) The value to set to
        """
        if not value:
            self.last_regen = timezone.now()
        self.asked_regen = value
        self.save()

    def __str__(self):
        return str(self.server) + " " + str(self.service)


class OuverturePortList(RevMixin, AclMixin, models.Model):
    """Liste des ports ouverts sur une interface."""

    name = models.CharField(
        help_text=_("Name of the ports configuration"),
        max_length=255
    )

    class Meta:
        permissions = (
            ("view_ouvertureportlist", _("Can view a ports opening list"
                                         " object")),
        )
        verbose_name = _("ports opening list")
        verbose_name_plural = _("ports opening lists")

    def can_delete(self, user_request, *_args, **_kwargs):
        """Verifie que l'user a les bons droits bureau pour delete
        cette instance ouvertureportlist
        :param self: Instance ouvertureportlist à delete
        :param user_request: Utilisateur qui fait la requête
        :return: soit True, soit False avec la raison de l'échec"""
        if not user_request.has_perm('machines.delete_ouvertureportlist'):
            return False, _("You don't have the right to delete a ports"
                            " opening list.")
        if self.interface_set.all():
            return False, _("This ports opening list is used.")
        return True, None

    def __str__(self):
        return self.name

    def tcp_ports_in(self):
        """Renvoie la liste des ports ouverts en TCP IN pour ce profil"""
        return self.ouvertureport_set.filter(
            protocole=OuverturePort.TCP,
            io=OuverturePort.IN
        )

    def udp_ports_in(self):
        """Renvoie la liste des ports ouverts en UDP IN pour ce profil"""
        return self.ouvertureport_set.filter(
            protocole=OuverturePort.UDP,
            io=OuverturePort.IN
        )

    def tcp_ports_out(self):
        """Renvoie la liste des ports ouverts en TCP OUT pour ce profil"""
        return self.ouvertureport_set.filter(
            protocole=OuverturePort.TCP,
            io=OuverturePort.OUT
        )

    def udp_ports_out(self):
        """Renvoie la liste des ports ouverts en UDP OUT pour ce profil"""
        return self.ouvertureport_set.filter(
            protocole=OuverturePort.UDP,
            io=OuverturePort.OUT
        )


class OuverturePort(RevMixin, AclMixin, models.Model):
    """
    Représente un simple port ou une plage de ports.

    Les ports de la plage sont compris entre begin et en inclus.
    Si begin == end alors on ne représente qu'un seul port.

    On limite les ports entre 0 et 65535, tels que défini par la RFC
    """

    TCP = 'T'
    UDP = 'U'
    IN = 'I'
    OUT = 'O'
    begin = models.PositiveIntegerField(validators=[MaxValueValidator(65535)])
    end = models.PositiveIntegerField(validators=[MaxValueValidator(65535)])
    port_list = models.ForeignKey(
        'OuverturePortList',
        on_delete=models.CASCADE
    )
    protocole = models.CharField(
        max_length=1,
        choices=(
            (TCP, 'TCP'),
            (UDP, 'UDP'),
        ),
        default=TCP,
    )
    io = models.CharField(
        max_length=1,
        choices=(
            (IN, 'IN'),
            (OUT, 'OUT'),
        ),
        default=OUT,
    )
    
    class Meta:
        verbose_name = _("ports opening")
        verbose_name = _("ports openings")

    def __str__(self):
        if self.begin == self.end:
            return str(self.begin)
        return ':'.join([str(self.begin), str(self.end)])

    def show_port(self):
        """Formatage plus joli, alias pour str"""
        return str(self)


@receiver(post_save, sender=Machine)
def machine_post_save(**kwargs):
    """Synchronisation ldap et régen parefeu/dhcp lors de la modification
    d'une machine"""
    user = kwargs['instance'].user
    user.ldap_sync(base=False, access_refresh=False, mac_refresh=True)
    regen('dhcp')
    regen('mac_ip_list')


@receiver(post_delete, sender=Machine)
def machine_post_delete(**kwargs):
    """Synchronisation ldap et régen parefeu/dhcp lors de la suppression
    d'une machine"""
    machine = kwargs['instance']
    user = machine.user
    user.ldap_sync(base=False, access_refresh=False, mac_refresh=True)
    regen('dhcp')
    regen('mac_ip_list')


@receiver(post_save, sender=Interface)
def interface_post_save(**kwargs):
    """Synchronisation ldap et régen parefeu/dhcp lors de la modification
    d'une interface"""
    interface = kwargs['instance']
    interface.sync_ipv6()
    user = interface.machine.user
    user.ldap_sync(base=False, access_refresh=False, mac_refresh=True)
    # Regen services
    regen('dhcp')
    regen('mac_ip_list')


@receiver(post_delete, sender=Interface)
def interface_post_delete(**kwargs):
    """Synchronisation ldap et régen parefeu/dhcp lors de la suppression
    d'une interface"""
    interface = kwargs['instance']
    user = interface.machine.user
    user.ldap_sync(base=False, access_refresh=False, mac_refresh=True)


@receiver(post_save, sender=IpType)
def iptype_post_save(**kwargs):
    """Generation des objets ip après modification d'un range ip"""
    iptype = kwargs['instance']
    iptype.gen_ip_range()
    iptype.check_replace_prefixv6()


@receiver(post_save, sender=MachineType)
def machinetype_post_save(**kwargs):
    """Mise à jour des interfaces lorsque changement d'attribution
    d'une machinetype (changement iptype parent)"""
    machinetype = kwargs['instance']
    for interface in machinetype.all_interfaces():
        interface.update_type()


@receiver(post_save, sender=Domain)
def domain_post_save(**_kwargs):
    """Regeneration dns après modification d'un domain object"""
    regen('dns')


@receiver(post_delete, sender=Domain)
def domain_post_delete(**_kwargs):
    """Regeneration dns après suppression d'un domain object"""
    regen('dns')


@receiver(post_save, sender=Extension)
def extension_post_save(**_kwargs):
    """Regeneration dns après modification d'une extension"""
    regen('dns')


@receiver(post_delete, sender=Extension)
def extension_post_selete(**_kwargs):
    """Regeneration dns après suppression d'une extension"""
    regen('dns')


@receiver(post_save, sender=SOA)
def soa_post_save(**_kwargs):
    """Regeneration dns après modification d'un SOA"""
    regen('dns')


@receiver(post_delete, sender=SOA)
def soa_post_delete(**_kwargs):
    """Regeneration dns après suppresson d'un SOA"""
    regen('dns')


@receiver(post_save, sender=Mx)
def mx_post_save(**_kwargs):
    """Regeneration dns après modification d'un MX"""
    regen('dns')


@receiver(post_delete, sender=Mx)
def mx_post_delete(**_kwargs):
    """Regeneration dns après suppresson d'un MX"""
    regen('dns')


@receiver(post_save, sender=Ns)
def ns_post_save(**_kwargs):
    """Regeneration dns après modification d'un NS"""
    regen('dns')


@receiver(post_delete, sender=Ns)
def ns_post_delete(**_kwargs):
    """Regeneration dns après modification d'un NS"""
    regen('dns')


@receiver(post_save, sender=Txt)
def text_post_save(**_kwargs):
    """Regeneration dns après modification d'un TXT"""
    regen('dns')


@receiver(post_delete, sender=Txt)
def text_post_delete(**_kwargs):
    """Regeneration dns après modification d'un TX"""
    regen('dns')


@receiver(post_save, sender=DName)
def dname_post_save(**_kwargs):
    """Updates the DNS regen after modification of a DName object."""
    regen('dns')


@receiver(post_delete, sender=DName)
def dname_post_delete(**_kwargs):
    """Updates the DNS regen after deletion of a DName object."""
    regen('dns')


@receiver(post_save, sender=Srv)
def srv_post_save(**_kwargs):
    """Regeneration dns après modification d'un SRV"""
    regen('dns')


@receiver(post_delete, sender=Srv)
def srv_post_delete(**_kwargs):
    """Regeneration dns après modification d'un SRV"""
    regen('dns')