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
  28 class SubnetException(Exception):
  29     """Base element for Subnet errors"""
  30     pass
  31
  32
  33 class SubnetNotFound(SubnetException):
  34     """The subnet requested does not exist."""
  35     pass
  36
  37
  38 class SubnetAlreadyExists(SubnetException):
  39     """The subnet being added already exists."""
  40     pass
  41
  42
  43 class SubnetInvalid(SubnetException):
  44     """The subnet CIDR is invalid."""
  45     pass
  46
  47
  48 class SiteNotFound(SubnetException):
  49     """The site to be used for the subnet does not exist."""
  50     pass
  51
  52
  53 def create_subnet(samdb, configDn, subnet_name, site_name):
  54     """Create a subnet and associate it with a site.
  55
  56     :param samdb: A samdb connection
  57     :param configDn: The DN of the configuration partition
  58     :param subnet_name: name of the subnet to create (a CIDR range)
  59     :return: None
  60     :raise SubnetAlreadyExists: if the subnet to be created already exists.
  61     :raise SiteNotFound: if the site does not exist.
  62     """
  63     ret = samdb.search(base=configDn, scope=ldb.SCOPE_SUBTREE,
  64                        expression='(&(objectclass=Site)(cn=%s))' %
  65                        ldb.binary_encode(site_name))
  66     if len(ret) != 1:
  67         raise SiteNotFound('A site with the name %s does not exist' %
  68                            site_name)
  69     dn_site = ret[0].dn
  70
  71     if not isinstance(subnet_name, str):
  72         raise SubnetInvalid("%s is not a valid subnet (not a string)" % subnet_name)
  73
  74     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
  75     try:
  76         dnsubnet.add_base(configDn)
  77     except ldb.LdbError:
  78         raise SubnetException("dnsubnet.add_base() failed")
  79     try:
  80         dnsubnet.add_child("CN=X")
  81     except ldb.LdbError:
  82         raise SubnetException("dnsubnet.add_child() failed")
  83     dnsubnet.set_component(0, "CN", subnet_name)
  84
  85     try:
  86         m = ldb.Message()
  87         m.dn = dnsubnet
  88         m["objectclass"] = ldb.MessageElement("subnet", FLAG_MOD_ADD,
  89                                               "objectclass")
  90         m["siteObject"] = ldb.MessageElement(str(dn_site), FLAG_MOD_ADD,
  91                                              "siteObject")
  92         samdb.add(m)
  93     except ldb.LdbError as e:
  94         (enum, estr) = e.args
  95         if enum == ldb.ERR_INVALID_DN_SYNTAX:
  96             raise SubnetInvalid("%s is not a valid subnet: %s" % (subnet_name, estr))
  97         elif enum == ldb.ERR_ENTRY_ALREADY_EXISTS:
  98             # Subnet collisions are checked by exact match only, not
  99             # overlapping range. This won't stop you creating
 100             # 10.1.1.0/24 when there is already 10.1.0.0/16, or
 101             # prevent you from having numerous IPv6 subnets that refer
 102             # to the same range (e.g 5::0/16, 5::/16, 5:0:0::/16).
 103             raise SubnetAlreadyExists('A subnet with the CIDR %s already exists'
 104                                       % subnet_name)
 105         else:
 106             raise
 107
 108
 109 def delete_subnet(samdb, configDn, subnet_name):
 110     """Delete a subnet.
 111
 112     :param samdb: A samdb connection
 113     :param configDn: The DN of the configuration partition
 114     :param subnet_name: Name of the subnet to delete
 115     :return: None
 116     :raise SubnetNotFound: if the subnet to be deleted does not exist.
 117     """
 118     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
 119     try:
 120         dnsubnet.add_base(configDn)
 121     except ldb.LdbError:
 122         raise SubnetException("dnsubnet.add_base() failed")
 123     try:
 124         dnsubnet.add_child("CN=X")
 125     except ldb.LdbError:
 126         raise SubnetException("dnsubnet.add_child() failed")
 127     dnsubnet.set_component(0, "CN", subnet_name)
 128
 129     try:
 130         ret = samdb.search(base=dnsubnet, scope=ldb.SCOPE_BASE,
 131                            expression="objectClass=subnet")
 132         if len(ret) != 1:
 133             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 134     except LdbError as e1:
 135         (enum, estr) = e1.args
 136         if enum == ldb.ERR_NO_SUCH_OBJECT:
 137             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 138
 139     samdb.delete(dnsubnet)
 140
 141
 142 def rename_subnet(samdb, configDn, subnet_name, new_name):
 143     """Rename a subnet.
 144
 145     :param samdb: A samdb connection
 146     :param configDn: The DN of the configuration partition
 147     :param subnet_name: Name of the subnet to rename
 148     :param new_name: New name for the subnet
 149     :return: None
 150     :raise SubnetNotFound: if the subnet to be renamed does not exist.
 151     :raise SubnetExists: if the subnet to be created already exists.
 152     """
 153     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
 154     try:
 155         dnsubnet.add_base(configDn)
 156     except ldb.LdbError:
 157         raise SubnetException("dnsubnet.add_base() failed")
 158     try:
 159         dnsubnet.add_child("CN=X")
 160     except ldb.LdbError:
 161         raise SubnetException("dnsubnet.add_child() failed")
 162     dnsubnet.set_component(0, "CN", subnet_name)
 163
 164     newdnsubnet = ldb.Dn(samdb, str(dnsubnet))
 165     newdnsubnet.set_component(0, "CN", new_name)
 166     try:
 167         samdb.rename(dnsubnet, newdnsubnet)
 168     except LdbError as e2:
 169         (enum, estr) = e2.args
 170         if enum == ldb.ERR_NO_SUCH_OBJECT:
 171             raise SubnetNotFound('Subnet %s does not exist' % dnsubnet)
 172         elif enum == ldb.ERR_ENTRY_ALREADY_EXISTS:
 173             raise SubnetAlreadyExists('A subnet with the CIDR %s already exists'
 174                                       % new_name)
 175         elif enum == ldb.ERR_INVALID_DN_SYNTAX:
 176             raise SubnetInvalid("%s is not a valid subnet: %s" % (new_name,
 177                                                                   estr))
 178         else:
 179             raise
 180
 181
 182 def set_subnet_site(samdb, configDn, subnet_name, site_name):
 183     """Assign a subnet to a site.
 184
 185     This dissociates the subnet from its previous site.
 186
 187     :param samdb: A samdb connection
 188     :param configDn: The DN of the configuration partition
 189     :param subnet_name: Name of the subnet
 190     :param site_name: Name of the site
 191     :return: None
 192     :raise SubnetNotFound: if the subnet does not exist.
 193     :raise SiteNotFound: if the site does not exist.
 194     """
 195
 196     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
 197     try:
 198         dnsubnet.add_base(configDn)
 199     except ldb.LdbError:
 200         raise SubnetException("dnsubnet.add_base() failed")
 201     try:
 202         dnsubnet.add_child("CN=X")
 203     except ldb.LdbError:
 204         raise SubnetException("dnsubnet.add_child() failed")
 205     dnsubnet.set_component(0, "CN", subnet_name)
 206
 207     try:
 208         ret = samdb.search(base=dnsubnet, scope=ldb.SCOPE_BASE,
 209                            expression="objectClass=subnet")
 210         if len(ret) != 1:
 211             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 212     except LdbError as e3:
 213         (enum, estr) = e3.args
 214         if enum == ldb.ERR_NO_SUCH_OBJECT:
 215             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 216
 217     dnsite = ldb.Dn(samdb, "CN=Sites")
 218     try:
 219         dnsite.add_base(configDn)
 220     except ldb.LdbError:
 221         raise SubnetException("dnsite.add_base() failed")
 222     try:
 223         dnsite.add_child("CN=X")
 224     except ldb.LdbError:
 225         raise SubnetException("dnsite.add_child() failed")
 226     dnsite.set_component(0, "CN", site_name)
 227
 228     dnservers = ldb.Dn(samdb, "CN=Servers")
 229     dnservers.add_base(dnsite)
 230
 231     try:
 232         ret = samdb.search(base=dnsite, scope=ldb.SCOPE_BASE,
 233                            expression="objectClass=site")
 234         if len(ret) != 1:
 235             raise SiteNotFoundException('Site %s does not exist' % site_name)
 236     except LdbError as e4:
 237         (enum, estr) = e4.args
 238         if enum == ldb.ERR_NO_SUCH_OBJECT:
 239             raise SiteNotFoundException('Site %s does not exist' % site_name)
 240
 241     siteDn = str(ret[0].dn)
 242
 243     m = ldb.Message()
 244     m.dn = dnsubnet
 245     m["siteObject"] = ldb.MessageElement(siteDn, FLAG_MOD_REPLACE,
 246                                          "siteObject")
 247     samdb.modify(m)