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     if dnsubnet.add_base(configDn) == False:
  76         raise SubnetException("dnsubnet.add_base() failed")
  77     if dnsubnet.add_child("CN=X") == False:
  78         raise SubnetException("dnsubnet.add_child() failed")
  79     dnsubnet.set_component(0, "CN", subnet_name)
  80
  81     try:
  82         m = ldb.Message()
  83         m.dn = dnsubnet
  84         m["objectclass"] = ldb.MessageElement("subnet", FLAG_MOD_ADD,
  85                                               "objectclass")
  86         m["siteObject"] = ldb.MessageElement(str(dn_site), FLAG_MOD_ADD,
  87                                              "siteObject")
  88         samdb.add(m)
  89     except ldb.LdbError as e:
  90         (enum, estr) = e.args
  91         if enum == ldb.ERR_INVALID_DN_SYNTAX:
  92             raise SubnetInvalid("%s is not a valid subnet: %s" % (subnet_name, estr))
  93         elif enum == ldb.ERR_ENTRY_ALREADY_EXISTS:
  94             # Subnet collisions are checked by exact match only, not
  95             # overlapping range. This won't stop you creating
  96             # 10.1.1.0/24 when there is already 10.1.0.0/16, or
  97             # prevent you from having numerous IPv6 subnets that refer
  98             # to the same range (e.g 5::0/16, 5::/16, 5:0:0::/16).
  99             raise SubnetAlreadyExists('A subnet with the CIDR %s already exists'
 100                                       % subnet_name)
 101         else:
 102             raise
 103
 104
 105 def delete_subnet(samdb, configDn, subnet_name):
 106     """Delete a subnet.
 107
 108     :param samdb: A samdb connection
 109     :param configDn: The DN of the configuration partition
 110     :param subnet_name: Name of the subnet to delete
 111     :return: None
 112     :raise SubnetNotFound: if the subnet to be deleted does not exist.
 113     """
 114     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
 115     if dnsubnet.add_base(configDn) == False:
 116         raise SubnetException("dnsubnet.add_base() failed")
 117     if dnsubnet.add_child("CN=X") == False:
 118         raise SubnetException("dnsubnet.add_child() failed")
 119     dnsubnet.set_component(0, "CN", subnet_name)
 120
 121     try:
 122         ret = samdb.search(base=dnsubnet, scope=ldb.SCOPE_BASE,
 123                            expression="objectClass=subnet")
 124         if len(ret) != 1:
 125             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 126     except LdbError as e1:
 127         (enum, estr) = e1.args
 128         if enum == ldb.ERR_NO_SUCH_OBJECT:
 129             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 130
 131     samdb.delete(dnsubnet)
 132
 133
 134 def rename_subnet(samdb, configDn, subnet_name, new_name):
 135     """Rename a subnet.
 136
 137     :param samdb: A samdb connection
 138     :param configDn: The DN of the configuration partition
 139     :param subnet_name: Name of the subnet to rename
 140     :param new_name: New name for the subnet
 141     :return: None
 142     :raise SubnetNotFound: if the subnet to be renamed does not exist.
 143     :raise SubnetExists: if the subnet to be created already exists.
 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     newdnsubnet = ldb.Dn(samdb, str(dnsubnet))
 153     newdnsubnet.set_component(0, "CN", new_name)
 154     try:
 155         samdb.rename(dnsubnet, newdnsubnet)
 156     except LdbError as e2:
 157         (enum, estr) = e2.args
 158         if enum == ldb.ERR_NO_SUCH_OBJECT:
 159             raise SubnetNotFound('Subnet %s does not exist' % dnsubnet)
 160         elif enum == ldb.ERR_ENTRY_ALREADY_EXISTS:
 161             raise SubnetAlreadyExists('A subnet with the CIDR %s already exists'
 162                                       % new_name)
 163         elif enum == ldb.ERR_INVALID_DN_SYNTAX:
 164             raise SubnetInvalid("%s is not a valid subnet: %s" % (new_name,
 165                                                                   estr))
 166         else:
 167             raise
 168
 169
 170 def set_subnet_site(samdb, configDn, subnet_name, site_name):
 171     """Assign a subnet to a site.
 172
 173     This dissociates the subnet from its previous site.
 174
 175     :param samdb: A samdb connection
 176     :param configDn: The DN of the configuration partition
 177     :param subnet_name: Name of the subnet
 178     :param site_name: Name of the site
 179     :return: None
 180     :raise SubnetNotFound: if the subnet does not exist.
 181     :raise SiteNotFound: if the site does not exist.
 182     """
 183
 184     dnsubnet = ldb.Dn(samdb, "CN=Subnets,CN=Sites")
 185     if dnsubnet.add_base(configDn) == False:
 186         raise SubnetException("dnsubnet.add_base() failed")
 187     if dnsubnet.add_child("CN=X") == False:
 188         raise SubnetException("dnsubnet.add_child() failed")
 189     dnsubnet.set_component(0, "CN", subnet_name)
 190
 191     try:
 192         ret = samdb.search(base=dnsubnet, scope=ldb.SCOPE_BASE,
 193                            expression="objectClass=subnet")
 194         if len(ret) != 1:
 195             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 196     except LdbError as e3:
 197         (enum, estr) = e3.args
 198         if enum == ldb.ERR_NO_SUCH_OBJECT:
 199             raise SubnetNotFound('Subnet %s does not exist' % subnet_name)
 200
 201     dnsite = ldb.Dn(samdb, "CN=Sites")
 202     if dnsite.add_base(configDn) == False:
 203         raise SubnetException("dnsites.add_base() failed")
 204     if dnsite.add_child("CN=X") == False:
 205         raise SubnetException("dnsites.add_child() failed")
 206     dnsite.set_component(0, "CN", site_name)
 207
 208     dnservers = ldb.Dn(samdb, "CN=Servers")
 209     dnservers.add_base(dnsite)
 210
 211     try:
 212         ret = samdb.search(base=dnsite, scope=ldb.SCOPE_BASE,
 213                            expression="objectClass=site")
 214         if len(ret) != 1:
 215             raise SiteNotFoundException('Site %s does not exist' % site_name)
 216     except LdbError as e4:
 217         (enum, estr) = e4.args
 218         if enum == ldb.ERR_NO_SUCH_OBJECT:
 219             raise SiteNotFoundException('Site %s does not exist' % site_name)
 220
 221     siteDn = str(ret[0].dn)
 222
 223     m = ldb.Message()
 224     m.dn = dnsubnet
 225     m["siteObject"] = ldb.MessageElement(siteDn, FLAG_MOD_REPLACE,
 226                                          "siteObject")
 227     samdb.modify(m)