python/samba/subnets.py

   1 # Add/remove subnets to sites.
   2 #
   3 # Copyright (C) Catalyst.Net Ltd 2015
   4 # Copyright Matthieu Patou <mat@matws.net> 2011
   5 #
   6 # Catalyst.Net's contribution was written by Douglas Bagnall
   7 # <douglas.bagnall@catalyst.net.nz>.
   8 #
   9 # This program is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 3 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # This program is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 #
  22
  23 import ldb
  24 from ldb import FLAG_MOD_ADD, FLAG_MOD_REPLACE, LdbError
  25 from sites import SiteNotFoundException
  26
  27 class SubnetException(Exception):
  28     """Base element for Subnet errors"""
  29     pass
  30
  31
  32 class SubnetNotFound(SubnetException):
  33     """The subnet requested does not exist."""
  34     pass
  35
  36
  37 class SubnetAlreadyExists(SubnetException):
  38     """The subnet being added already exists."""
  39     pass
  40
  41
  42 class SubnetInvalid(SubnetException):
  43     """The subnet CIDR is invalid."""
  44     pass
  45
  46
  47 class SiteNotFound(SubnetException):
  48     """The site to be used for the subnet does not exist."""
  49     pass
  50
  51
  52 def create_subnet(samdb, configDn, subnet_name, site_name):
  53     """Create a subnet and associate it with a site.
  54
  55     :param samdb: A samdb connection
  56     :param configDn: The DN of the configuration partition
  57     :param subnet_name: name of the subnet to create (a CIDR range)
  58     :return: None
  59     :raise SubnetAlreadyExists: if the subnet to be created already exists.
  60     :raise SiteNotFound: if the site does not exist.
  61     """
  62     ret = samdb.search(base=configDn, scope=ldb.SCOPE_SUBTREE,
  63                        expression='(&(objectclass=Site)(cn=%s))' %
  64                        ldb.binary_encode(site_name))
  65     if len(ret) != 1:
  66         raise SiteNotFound('A site with the name %s does not exist' %
  67                            site_name)
  68     dn_site = ret[0].dn
  69
  70     if not isinstance(subnet_name, str):
  71         raise SubnetInvalid("%s is not a valid subnet (not a string)" % subnet_name)
  72
  73     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
  74     if dnsubnet.add_base(configDn) == False:
  75         raise SubnetException("dnsubnet.add_base() failed")
  76     if dnsubnet.add_child("CN=X") == False:
  77         raise SubnetException("dnsubnet.add_child() failed")
  78     dnsubnet.set_component(0, "CN", subnet_name)
  79
  80     try:
  81         m = ldb.Message()
  82         m.dn = dnsubnet
  83         m["objectclass"] = ldb.MessageElement("subnet", FLAG_MOD_ADD,
  84                                               "objectclass")
  85         m["siteObject"] = ldb.MessageElement(str(dn_site), FLAG_MOD_ADD,
  86                                              "siteObject")
  87         samdb.add(m)
  88     except ldb.LdbError as (enum, estr):
  89         if enum == ldb.ERR_INVALID_DN_SYNTAX:
  90             raise SubnetInvalid("%s is not a valid subnet: %s" % (subnet_name, estr))
  91         elif enum == ldb.ERR_ENTRY_ALREADY_EXISTS:
  92             # Subnet collisions are checked by exact match only, not
  93             # overlapping range. This won't stop you creating
  94             # 10.1.1.0/24 when there is already 10.1.0.0/16, or
  95             # prevent you from having numerous IPv6 subnets that refer
  96             # to the same range (e.g 5::0/16, 5::/16, 5:0:0::/16).
  97             raise SubnetAlreadyExists('A subnet with the CIDR %s already exists'
  98                                       % subnet_name)
  99         else:
 100             raise
 101
 102
 103 def delete_subnet(samdb, configDn, subnet_name):
 104     """Delete a subnet.
 105
 106     :param samdb: A samdb connection
 107     :param configDn: The DN of the configuration partition
 108     :param subnet_name: Name of the subnet to delete
 109     :return: None
 110     :raise SubnetNotFound: if the subnet to be deleted does not exist.
 111     """
 112     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
 113     if dnsubnet.add_base(configDn) == False:
 114         raise SubnetException("dnsubnet.add_base() failed")
 115     if dnsubnet.add_child("CN=X") == False:
 116         raise SubnetException("dnsubnet.add_child() failed")
 117     dnsubnet.set_component(0, "CN", subnet_name)
 118
 119     try:
 120         ret = samdb.search(base=dnsubnet, scope=ldb.SCOPE_BASE,
 121                            expression="objectClass=subnet")
 122         if len(ret) != 1:
 123             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 124     except LdbError as (enum, estr):
 125         if enum == ldb.ERR_NO_SUCH_OBJECT:
 126             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 127
 128     samdb.delete(dnsubnet)
 129
 130
 131 def set_subnet_site(samdb, configDn, subnet_name, site_name):
 132     """Assign a subnet to a site.
 133
 134     This dissociates the subnet from its previous site.
 135
 136     :param samdb: A samdb connection
 137     :param configDn: The DN of the configuration partition
 138     :param subnet_name: Name of the subnet
 139     :param site_name: Name of the site
 140     :return: None
 141     :raise SubnetNotFound: if the subnet does not exist.
 142     :raise SiteNotFound: if the site does not exist.
 143     """
 144
 145     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
 146     if dnsubnet.add_base(configDn) == False:
 147         raise SubnetException("dnsubnet.add_base() failed")
 148     if dnsubnet.add_child("CN=X") == False:
 149         raise SubnetException("dnsubnet.add_child() failed")
 150     dnsubnet.set_component(0, "CN", subnet_name)
 151
 152     try:
 153         ret = samdb.search(base=dnsubnet, scope=ldb.SCOPE_BASE,
 154                            expression="objectClass=subnet")
 155         if len(ret) != 1:
 156             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 157     except LdbError as (enum, estr):
 158         if enum == ldb.ERR_NO_SUCH_OBJECT:
 159             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 160
 161     dnsite = ldb.Dn(samdb, "CN=Sites")
 162     if dnsite.add_base(configDn) == False:
 163         raise SubnetException("dnsites.add_base() failed")
 164     if dnsite.add_child("CN=X") == False:
 165         raise SubnetException("dnsites.add_child() failed")
 166     dnsite.set_component(0, "CN", site_name)
 167
 168     dnservers = ldb.Dn(samdb, "CN=Servers")
 169     dnservers.add_base(dnsite)
 170
 171     try:
 172         ret = samdb.search(base=dnsite, scope=ldb.SCOPE_BASE,
 173                            expression="objectClass=site")
 174         if len(ret) != 1:
 175             raise SiteNotFoundException('Site %s does not exist' % site_name)
 176     except LdbError as (enum, estr):
 177         if enum == ldb.ERR_NO_SUCH_OBJECT:
 178             raise SiteNotFoundException('Site %s does not exist' % site_name)
 179
 180     siteDn = str(ret[0].dn)
 181
 182     m = ldb.Message()
 183     m.dn = dnsubnet
 184     m["siteObject"] = ldb.MessageElement(siteDn, FLAG_MOD_REPLACE,
 185                                          "siteObject")
 186     samdb.modify(m)