# Unix SMB/CIFS implementation.
# backend code for provisioning DNS for a Samba4 server
#
# Copyright (C) Kai Blin <kai@samba.org> 2011
# Copyright (C) Amitay Isaacs <amitay@gmail.com> 2011
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
#

"""DNS-related provisioning"""

import os
import uuid
import shutil
import time
import ldb
from base64 import b64encode
import subprocess
import samba
from samba.tdb_util import tdb_copy
from samba.ndr import ndr_pack, ndr_unpack
from samba import setup_file
from samba.dcerpc import dnsp, misc, security
from samba.dsdb import (
    DS_DOMAIN_FUNCTION_2000,
    DS_DOMAIN_FUNCTION_2003,
    DS_DOMAIN_FUNCTION_2008_R2,
    DS_DOMAIN_FUNCTION_2012_R2
    )
from samba.descriptor import (
    get_domain_descriptor,
    get_domain_delete_protected1_descriptor,
    get_domain_delete_protected2_descriptor,
    get_dns_partition_descriptor,
    get_dns_forest_microsoft_dns_descriptor,
    get_dns_domain_microsoft_dns_descriptor
    )
from samba.provision.common import (
    setup_path,
    setup_add_ldif,
    setup_modify_ldif,
    setup_ldb,
    FILL_FULL,
    FILL_SUBDOMAIN,
    FILL_NT4SYNC,
    FILL_DRS,
    )


def get_domainguid(samdb, domaindn):
    res = samdb.search(base=domaindn, scope=ldb.SCOPE_BASE, attrs=["objectGUID"])
    domainguid =  str(ndr_unpack(misc.GUID, res[0]["objectGUID"][0]))
    return domainguid


def get_dnsadmins_sid(samdb, domaindn):
    res = samdb.search(base="CN=DnsAdmins,CN=Users,%s" % domaindn, scope=ldb.SCOPE_BASE,
                       attrs=["objectSid"])
    dnsadmins_sid = ndr_unpack(security.dom_sid, res[0]["objectSid"][0])
    return dnsadmins_sid


class ARecord(dnsp.DnssrvRpcRecord):

    def __init__(self, ip_addr, serial=1, ttl=900, rank=dnsp.DNS_RANK_ZONE):
        super(ARecord, self).__init__()
        self.wType = dnsp.DNS_TYPE_A
        self.rank = rank
        self.dwSerial = serial
        self.dwTtlSeconds = ttl
        self.data = ip_addr


class AAAARecord(dnsp.DnssrvRpcRecord):

    def __init__(self, ip6_addr, serial=1, ttl=900, rank=dnsp.DNS_RANK_ZONE):
        super(AAAARecord, self).__init__()
        self.wType = dnsp.DNS_TYPE_AAAA
        self.rank = rank
        self.dwSerial = serial
        self.dwTtlSeconds = ttl
        self.data = ip6_addr


class CNameRecord(dnsp.DnssrvRpcRecord):

    def __init__(self, cname, serial=1, ttl=900, rank=dnsp.DNS_RANK_ZONE):
        super(CNameRecord, self).__init__()
        self.wType = dnsp.DNS_TYPE_CNAME
        self.rank = rank
        self.dwSerial = serial
        self.dwTtlSeconds = ttl
        self.data = cname


class NSRecord(dnsp.DnssrvRpcRecord):

    def __init__(self, dns_server, serial=1, ttl=900, rank=dnsp.DNS_RANK_ZONE):
        super(NSRecord, self).__init__()
        self.wType = dnsp.DNS_TYPE_NS
        self.rank = rank
        self.dwSerial = serial
        self.dwTtlSeconds = ttl
        self.data = dns_server


class SOARecord(dnsp.DnssrvRpcRecord):

    def __init__(self, mname, rname, serial=1, refresh=900, retry=600,
                 expire=86400, minimum=3600, ttl=3600, rank=dnsp.DNS_RANK_ZONE):
        super(SOARecord, self).__init__()
        self.wType = dnsp.DNS_TYPE_SOA
        self.rank = rank
        self.dwSerial = serial
        self.dwTtlSeconds = ttl
        soa = dnsp.soa()
        soa.serial = serial
        soa.refresh = refresh
        soa.retry = retry
        soa.expire = expire
        soa.mname = mname
        soa.rname = rname
        soa.minimum = minimum
        self.data = soa


class SRVRecord(dnsp.DnssrvRpcRecord):

    def __init__(self, target, port, priority=0, weight=100, serial=1, ttl=900,
                rank=dnsp.DNS_RANK_ZONE):
        super(SRVRecord, self).__init__()
        self.wType = dnsp.DNS_TYPE_SRV
        self.rank = rank
        self.dwSerial = serial
        self.dwTtlSeconds = ttl
        srv = dnsp.srv()
        srv.nameTarget = target
        srv.wPort = port
        srv.wPriority = priority
        srv.wWeight = weight
        self.data = srv


class TXTRecord(dnsp.DnssrvRpcRecord):

    def __init__(self, slist, serial=1, ttl=900, rank=dnsp.DNS_RANK_ZONE):
        super(TXTRecord, self).__init__()
        self.wType = dnsp.DNS_TYPE_TXT
        self.rank = rank
        self.dwSerial = serial
        self.dwTtlSeconds = ttl
        stringlist = dnsp.string_list()
        stringlist.count = len(slist)
        stringlist.str = slist
        self.data = stringlist


class TypeProperty(dnsp.DnsProperty):

    def __init__(self, zone_type=dnsp.DNS_ZONE_TYPE_PRIMARY):
        super(TypeProperty, self).__init__()
        self.wDataLength = 1
        self.version = 1
        self.id = dnsp.DSPROPERTY_ZONE_TYPE
        self.data = zone_type


class AllowUpdateProperty(dnsp.DnsProperty):

    def __init__(self, allow_update=dnsp.DNS_ZONE_UPDATE_SECURE):
        super(AllowUpdateProperty, self).__init__()
        self.wDataLength = 1
        self.version = 1
        self.id = dnsp.DSPROPERTY_ZONE_ALLOW_UPDATE
        self.data = allow_update


class SecureTimeProperty(dnsp.DnsProperty):

    def __init__(self, secure_time=0):
        super(SecureTimeProperty, self).__init__()
        self.wDataLength = 1
        self.version = 1
        self.id = dnsp.DSPROPERTY_ZONE_SECURE_TIME
        self.data = secure_time


class NorefreshIntervalProperty(dnsp.DnsProperty):

    def __init__(self, norefresh_interval=0):
        super(NorefreshIntervalProperty, self).__init__()
        self.wDataLength = 1
        self.version = 1
        self.id = dnsp.DSPROPERTY_ZONE_NOREFRESH_INTERVAL
        self.data = norefresh_interval


class RefreshIntervalProperty(dnsp.DnsProperty):

    def __init__(self, refresh_interval=0):
        super(RefreshIntervalProperty, self).__init__()
        self.wDataLength = 1
        self.version = 1
        self.id = dnsp.DSPROPERTY_ZONE_REFRESH_INTERVAL
        self.data = refresh_interval


class AgingStateProperty(dnsp.DnsProperty):

    def __init__(self, aging_enabled=0):
        super(AgingStateProperty, self).__init__()
        self.wDataLength = 1
        self.version = 1
        self.id = dnsp.DSPROPERTY_ZONE_AGING_STATE
        self.data = aging_enabled


class AgingEnabledTimeProperty(dnsp.DnsProperty):

    def __init__(self, next_cycle_hours=0):
        super(AgingEnabledTimeProperty, self).__init__()
        self.wDataLength = 1
        self.version = 1;
        self.id = dnsp.DSPROPERTY_ZONE_AGING_ENABLED_TIME
        self.data = next_cycle_hours


def setup_dns_partitions(samdb, domainsid, domaindn, forestdn, configdn,
                         serverdn, fill_level):
    domainzone_dn = "DC=DomainDnsZones,%s" % domaindn
    forestzone_dn = "DC=ForestDnsZones,%s" % forestdn
    descriptor = get_dns_partition_descriptor(domainsid)

    setup_add_ldif(samdb, setup_path("provision_dnszones_partitions.ldif"), {
        "ZONE_DN": domainzone_dn,
        "SECDESC"      : b64encode(descriptor)
        })
    if fill_level != FILL_SUBDOMAIN:
        setup_add_ldif(samdb, setup_path("provision_dnszones_partitions.ldif"), {
            "ZONE_DN": forestzone_dn,
            "SECDESC"      : b64encode(descriptor)
        })

    domainzone_guid = get_domainguid(samdb, domainzone_dn)
    domainzone_guid = str(uuid.uuid4())
    domainzone_dns = ldb.Dn(samdb, domainzone_dn).canonical_ex_str().strip()

    protected1_desc = get_domain_delete_protected1_descriptor(domainsid)
    protected2_desc = get_domain_delete_protected2_descriptor(domainsid)
    setup_add_ldif(samdb, setup_path("provision_dnszones_add.ldif"), {
        "ZONE_DN": domainzone_dn,
        "ZONE_GUID": domainzone_guid,
        "ZONE_DNS": domainzone_dns,
        "CONFIGDN": configdn,
        "SERVERDN": serverdn,
        "LOSTANDFOUND_DESCRIPTOR": b64encode(protected2_desc),
        "INFRASTRUCTURE_DESCRIPTOR": b64encode(protected1_desc),
        })
    setup_modify_ldif(samdb, setup_path("provision_dnszones_modify.ldif"), {
        "CONFIGDN": configdn,
        "SERVERDN": serverdn,
        "ZONE_DN": domainzone_dn,
    })

    if fill_level != FILL_SUBDOMAIN:
        forestzone_guid = get_domainguid(samdb, forestzone_dn)
        forestzone_guid = str(uuid.uuid4())
        forestzone_dns = ldb.Dn(samdb, forestzone_dn).canonical_ex_str().strip()

        setup_add_ldif(samdb, setup_path("provision_dnszones_add.ldif"), {
            "ZONE_DN": forestzone_dn,
            "ZONE_GUID": forestzone_guid,
            "ZONE_DNS": forestzone_dns,
            "CONFIGDN": configdn,
            "SERVERDN": serverdn,
            "LOSTANDFOUND_DESCRIPTOR": b64encode(protected2_desc),
            "INFRASTRUCTURE_DESCRIPTOR": b64encode(protected1_desc),
        })
        setup_modify_ldif(samdb, setup_path("provision_dnszones_modify.ldif"), {
            "CONFIGDN": configdn,
            "SERVERDN": serverdn,
            "ZONE_DN": forestzone_dn,
        })


def add_dns_accounts(samdb, domaindn):
    setup_add_ldif(samdb, setup_path("provision_dns_accounts_add.ldif"), {
        "DOMAINDN": domaindn,
        })


def add_dns_container(samdb, domaindn, prefix, domain_sid, dnsadmins_sid, forest=False):
    name_map = {'DnsAdmins': str(dnsadmins_sid)}
    if forest is True:
        sd_val = get_dns_forest_microsoft_dns_descriptor(domain_sid,
                                                         name_map=name_map)
    else:
        sd_val = get_dns_domain_microsoft_dns_descriptor(domain_sid,
                                                         name_map=name_map)
    # CN=MicrosoftDNS,<PREFIX>,<DOMAINDN>
    msg = ldb.Message(ldb.Dn(samdb, "CN=MicrosoftDNS,%s,%s" % (prefix, domaindn)))
    msg["objectClass"] = ["top", "container"]
    msg["nTSecurityDescriptor"] = ldb.MessageElement(sd_val, ldb.FLAG_MOD_ADD,
        "nTSecurityDescriptor")
    samdb.add(msg)


def add_rootservers(samdb, domaindn, prefix):
    rootservers = {}
    rootservers["a.root-servers.net"] = "198.41.0.4"
    rootservers["b.root-servers.net"] = "192.228.79.201"
    rootservers["c.root-servers.net"] = "192.33.4.12"
    rootservers["d.root-servers.net"] = "128.8.10.90"
    rootservers["e.root-servers.net"] = "192.203.230.10"
    rootservers["f.root-servers.net"] = "192.5.5.241"
    rootservers["g.root-servers.net"] = "192.112.36.4"
    rootservers["h.root-servers.net"] = "128.63.2.53"
    rootservers["i.root-servers.net"] = "192.36.148.17"
    rootservers["j.root-servers.net"] = "192.58.128.30"
    rootservers["k.root-servers.net"] = "193.0.14.129"
    rootservers["l.root-servers.net"] = "199.7.83.42"
    rootservers["m.root-servers.net"] = "202.12.27.33"

    rootservers_v6 = {}
    rootservers_v6["a.root-servers.net"] = "2001:503:ba3e::2:30"
    rootservers_v6["f.root-servers.net"] = "2001:500:2f::f"
    rootservers_v6["h.root-servers.net"] = "2001:500:1::803f:235"
    rootservers_v6["j.root-servers.net"] = "2001:503:c27::2:30"
    rootservers_v6["k.root-servers.net"] = "2001:7fd::1"
    rootservers_v6["m.root-servers.net"] = "2001:dc3::35"

    container_dn = "DC=RootDNSServers,CN=MicrosoftDNS,%s,%s" % (prefix, domaindn)

    # Add DC=RootDNSServers,CN=MicrosoftDNS,<PREFIX>,<DOMAINDN>
    msg = ldb.Message(ldb.Dn(samdb, container_dn))
    props = []
    props.append(ndr_pack(TypeProperty(zone_type=dnsp.DNS_ZONE_TYPE_CACHE)))
    props.append(ndr_pack(AllowUpdateProperty(allow_update=dnsp.DNS_ZONE_UPDATE_OFF)))
    props.append(ndr_pack(SecureTimeProperty()))
    props.append(ndr_pack(NorefreshIntervalProperty()))
    props.append(ndr_pack(RefreshIntervalProperty()))
    props.append(ndr_pack(AgingStateProperty()))
    props.append(ndr_pack(AgingEnabledTimeProperty()))
    msg["objectClass"] = ["top", "dnsZone"]
    msg["cn"] = ldb.MessageElement("Zone", ldb.FLAG_MOD_ADD, "cn")
    msg["dNSProperty"] = ldb.MessageElement(props, ldb.FLAG_MOD_ADD, "dNSProperty")
    samdb.add(msg)

    # Add DC=@,DC=RootDNSServers,CN=MicrosoftDNS,<PREFIX>,<DOMAINDN>
    record = []
    for rserver in rootservers:
        record.append(ndr_pack(NSRecord(rserver, serial=0, ttl=0, rank=dnsp.DNS_RANK_ROOT_HINT)))

    msg = ldb.Message(ldb.Dn(samdb, "DC=@,%s" % container_dn))
    msg["objectClass"] = ["top", "dnsNode"]
    msg["dnsRecord"] = ldb.MessageElement(record, ldb.FLAG_MOD_ADD, "dnsRecord")
    samdb.add(msg)

    # Add DC=<rootserver>,DC=RootDNSServers,CN=MicrosoftDNS,<PREFIX>,<DOMAINDN>
    for rserver in rootservers:
        record = [ndr_pack(ARecord(rootservers[rserver], serial=0, ttl=0, rank=dnsp.DNS_RANK_ROOT_HINT))]
        # Add AAAA record as well (How does W2K* add IPv6 records?)
        #if rserver in rootservers_v6:
        #    record.append(ndr_pack(AAAARecord(rootservers_v6[rserver], serial=0, ttl=0)))
        msg = ldb.Message(ldb.Dn(samdb, "DC=%s,%s" % (rserver, container_dn)))
        msg["objectClass"] = ["top", "dnsNode"]
        msg["dnsRecord"] = ldb.MessageElement(record, ldb.FLAG_MOD_ADD, "dnsRecord")
        samdb.add(msg)

def add_at_record(samdb, container_dn, prefix, hostname, dnsdomain, hostip, hostip6):

    fqdn_hostname = "%s.%s" % (hostname, dnsdomain)

    at_records = []

    # SOA record
    at_soa_record = SOARecord(fqdn_hostname, "hostmaster.%s" % dnsdomain)
    at_records.append(ndr_pack(at_soa_record))

    # NS record
    at_ns_record = NSRecord(fqdn_hostname)
    at_records.append(ndr_pack(at_ns_record))

    if hostip is not None:
        # A record
        at_a_record = ARecord(hostip)
        at_records.append(ndr_pack(at_a_record))

    if hostip6 is not None:
        # AAAA record
        at_aaaa_record = AAAARecord(hostip6)
        at_records.append(ndr_pack(at_aaaa_record))

    msg = ldb.Message(ldb.Dn(samdb, "DC=@,%s" % container_dn))
    msg["objectClass"] = ["top", "dnsNode"]
    msg["dnsRecord"] = ldb.MessageElement(at_records, ldb.FLAG_MOD_ADD, "dnsRecord")
    samdb.add(msg)


def add_srv_record(samdb, container_dn, prefix, host, port):
    srv_record = SRVRecord(host, port)
    msg = ldb.Message(ldb.Dn(samdb, "%s,%s" % (prefix, container_dn)))
    msg["objectClass"] = ["top", "dnsNode"]
    msg["dnsRecord"] = ldb.MessageElement(ndr_pack(srv_record), ldb.FLAG_MOD_ADD, "dnsRecord")
    samdb.add(msg)


def add_ns_record(samdb, container_dn, prefix, host):
    ns_record = NSRecord(host)
    msg = ldb.Message(ldb.Dn(samdb, "%s,%s" % (prefix, container_dn)))
    msg["objectClass"] = ["top", "dnsNode"]
    msg["dnsRecord"] = ldb.MessageElement(ndr_pack(ns_record), ldb.FLAG_MOD_ADD, "dnsRecord")
    samdb.add(msg)


def add_ns_glue_record(samdb, container_dn, prefix, host):
    ns_record = NSRecord(host, rank=dnsp.DNS_RANK_NS_GLUE)
    msg = ldb.Message(ldb.Dn(samdb, "%s,%s" % (prefix, container_dn)))
    msg["objectClass"] = ["top", "dnsNode"]
    msg["dnsRecord"] = ldb.MessageElement(ndr_pack(ns_record), ldb.FLAG_MOD_ADD, "dnsRecord")
    samdb.add(msg)


def add_cname_record(samdb, container_dn, prefix, host):
    cname_record = CNameRecord(host)
    msg = ldb.Message(ldb.Dn(samdb, "%s,%s" % (prefix, container_dn)))
    msg["objectClass"] = ["top", "dnsNode"]
    msg["dnsRecord"] = ldb.MessageElement(ndr_pack(cname_record), ldb.FLAG_MOD_ADD, "dnsRecord")
    samdb.add(msg)


def add_host_record(samdb, container_dn, prefix, hostip, hostip6):
    host_records = []
    if hostip:
        a_record = ARecord(hostip)
        host_records.append(ndr_pack(a_record))
    if hostip6:
        aaaa_record = AAAARecord(hostip6)
        host_records.append(ndr_pack(aaaa_record))
    if host_records:
        msg = ldb.Message(ldb.Dn(samdb, "%s,%s" % (prefix, container_dn)))
        msg["objectClass"] = ["top", "dnsNode"]
        msg["dnsRecord"] = ldb.MessageElement(host_records, ldb.FLAG_MOD_ADD, "dnsRecord")
        samdb.add(msg)


def add_domain_record(samdb, domaindn, prefix, dnsdomain, domainsid, dnsadmins_sid):
    # DC=<DNSDOMAIN>,CN=MicrosoftDNS,<PREFIX>,<DOMAINDN>
    sddl = "O:SYG:BAD:AI" \
    "(A;;RPWPCRCCDCLCLORCWOWDSDDTSW;;;DA)" \
    "(A;;CC;;;AU)" \
    "(A;;RPLCLORC;;;WD)" \
    "(A;;RPWPCRCCDCLCLORCWOWDSDDTSW;;;SY)" \
    "(A;CI;RPWPCRCCDCLCRCWOWDSDDTSW;;;ED)" \
    "(A;CIID;RPWPCRCCDCLCRCWOWDSDDTSW;;;%s)" \
    "(A;CIID;RPWPCRCCDCLCRCWOWDSDDTSW;;;ED)" \
    "(OA;CIID;RPWPCR;91e647de-d96f-4b70-9557-d63ff4f3ccd8;;PS)" \
    "(A;CIID;RPWPCRCCDCLCLORCWOWDSDDTSW;;;EA)" \
    "(A;CIID;LC;;;RU)" \
    "(A;CIID;RPWPCRCCLCLORCWOWDSDSW;;;BA)" \
    "S:AI" % dnsadmins_sid
    sec = security.descriptor.from_sddl(sddl, domainsid)
    props = []
    props.append(ndr_pack(TypeProperty()))
    props.append(ndr_pack(AllowUpdateProperty()))
    props.append(ndr_pack(SecureTimeProperty()))
    props.append(ndr_pack(NorefreshIntervalProperty(norefresh_interval=168)))
    props.append(ndr_pack(RefreshIntervalProperty(refresh_interval=168)))
    props.append(ndr_pack(AgingStateProperty()))
    props.append(ndr_pack(AgingEnabledTimeProperty()))
    msg = ldb.Message(ldb.Dn(samdb, "DC=%s,CN=MicrosoftDNS,%s,%s" % (dnsdomain, prefix, domaindn)))
    msg["objectClass"] = ["top", "dnsZone"]
    msg["ntSecurityDescriptor"] = ldb.MessageElement(ndr_pack(sec), ldb.FLAG_MOD_ADD,
        "nTSecurityDescriptor")
    msg["dNSProperty"] = ldb.MessageElement(props, ldb.FLAG_MOD_ADD, "dNSProperty")
    samdb.add(msg)


def add_msdcs_record(samdb, forestdn, prefix, dnsforest):
    # DC=_msdcs.<DNSFOREST>,CN=MicrosoftDNS,<PREFIX>,<FORESTDN>
    msg = ldb.Message(ldb.Dn(samdb, "DC=_msdcs.%s,CN=MicrosoftDNS,%s,%s" %
                                    (dnsforest, prefix, forestdn)))
    msg["objectClass"] = ["top", "dnsZone"]
    samdb.add(msg)


def add_dc_domain_records(samdb, domaindn, prefix, site, dnsdomain, hostname,
        hostip, hostip6):

    fqdn_hostname = "%s.%s" % (hostname, dnsdomain)

    # Set up domain container - DC=<DNSDOMAIN>,CN=MicrosoftDNS,<PREFIX>,<DOMAINDN>
    domain_container_dn = ldb.Dn(samdb, "DC=%s,CN=MicrosoftDNS,%s,%s" %
                                    (dnsdomain, prefix, domaindn))

    # DC=@ record
    add_at_record(samdb, domain_container_dn, "DC=@", hostname, dnsdomain,
            hostip, hostip6)

    # DC=<HOSTNAME> record
    add_host_record(samdb, domain_container_dn, "DC=%s" % hostname, hostip,
            hostip6)

    # DC=_kerberos._tcp record
    add_srv_record(samdb, domain_container_dn, "DC=_kerberos._tcp",
            fqdn_hostname, 88)

    # DC=_kerberos._tcp.<SITENAME>._sites record
    add_srv_record(samdb, domain_container_dn, "DC=_kerberos._tcp.%s._sites" %
            site, fqdn_hostname, 88)

    # DC=_kerberos._udp record
    add_srv_record(samdb, domain_container_dn, "DC=_kerberos._udp",
            fqdn_hostname, 88)

    # DC=_kpasswd._tcp record
    add_srv_record(samdb, domain_container_dn, "DC=_kpasswd._tcp",
            fqdn_hostname, 464)

    # DC=_kpasswd._udp record
    add_srv_record(samdb, domain_container_dn, "DC=_kpasswd._udp",
            fqdn_hostname, 464)

    # DC=_ldap._tcp record
    add_srv_record(samdb, domain_container_dn, "DC=_ldap._tcp", fqdn_hostname,
            389)

    # DC=_ldap._tcp.<SITENAME>._sites record
    add_srv_record(samdb, domain_container_dn, "DC=_ldap._tcp.%s._sites" %
            site, fqdn_hostname, 389)

    # FIXME: The number of SRV records depend on the various roles this DC has.
    #        _gc and _msdcs records are added if the we are the forest dc and not subdomain dc
    #
    # Assumption: current DC is GC and add all the entries

    # DC=_gc._tcp record
    add_srv_record(samdb, domain_container_dn, "DC=_gc._tcp", fqdn_hostname,
            3268)

    # DC=_gc._tcp.<SITENAME>,_sites record
    add_srv_record(samdb, domain_container_dn, "DC=_gc._tcp.%s._sites" % site,
            fqdn_hostname, 3268)

    # DC=_msdcs record
    add_ns_glue_record(samdb, domain_container_dn, "DC=_msdcs", fqdn_hostname)

    # FIXME: Following entries are added only if DomainDnsZones and ForestDnsZones partitions
    #        are created
    #
    # Assumption: Additional entries won't hurt on os_level = 2000

    # DC=_ldap._tcp.<SITENAME>._sites.DomainDnsZones
    add_srv_record(samdb, domain_container_dn,
            "DC=_ldap._tcp.%s._sites.DomainDnsZones" % site, fqdn_hostname,
            389)

    # DC=_ldap._tcp.<SITENAME>._sites.ForestDnsZones
    add_srv_record(samdb, domain_container_dn,
            "DC=_ldap._tcp.%s._sites.ForestDnsZones" % site, fqdn_hostname,
            389)

    # DC=_ldap._tcp.DomainDnsZones
    add_srv_record(samdb, domain_container_dn, "DC=_ldap._tcp.DomainDnsZones",
                    fqdn_hostname, 389)

    # DC=_ldap._tcp.ForestDnsZones
    add_srv_record(samdb, domain_container_dn, "DC=_ldap._tcp.ForestDnsZones",
                    fqdn_hostname, 389)

    # DC=DomainDnsZones
    add_host_record(samdb, domain_container_dn, "DC=DomainDnsZones", hostip,
            hostip6)

    # DC=ForestDnsZones
    add_host_record(samdb, domain_container_dn, "DC=ForestDnsZones", hostip,
            hostip6)


def add_dc_msdcs_records(samdb, forestdn, prefix, site, dnsforest, hostname,
                            hostip, hostip6, domainguid, ntdsguid):

    fqdn_hostname = "%s.%s" % (hostname, dnsforest)

    # Set up forest container - DC=<DNSDOMAIN>,CN=MicrosoftDNS,<PREFIX>,<DOMAINDN>
    forest_container_dn = ldb.Dn(samdb, "DC=_msdcs.%s,CN=MicrosoftDNS,%s,%s" %
                                    (dnsforest, prefix, forestdn))

    # DC=@ record
    add_at_record(samdb, forest_container_dn, "DC=@", hostname, dnsforest,
            None, None)

    # DC=_kerberos._tcp.dc record
    add_srv_record(samdb, forest_container_dn, "DC=_kerberos._tcp.dc",
            fqdn_hostname, 88)

    # DC=_kerberos._tcp.<SITENAME>._sites.dc record
    add_srv_record(samdb, forest_container_dn,
            "DC=_kerberos._tcp.%s._sites.dc" % site, fqdn_hostname, 88)

    # DC=_ldap._tcp.dc record
    add_srv_record(samdb, forest_container_dn, "DC=_ldap._tcp.dc",
            fqdn_hostname, 389)

    # DC=_ldap._tcp.<SITENAME>._sites.dc record
    add_srv_record(samdb, forest_container_dn, "DC=_ldap._tcp.%s._sites.dc" %
            site, fqdn_hostname, 389)

    # DC=_ldap._tcp.<SITENAME>._sites.gc record
    add_srv_record(samdb, forest_container_dn, "DC=_ldap._tcp.%s._sites.gc" %
            site, fqdn_hostname, 3268)

    # DC=_ldap._tcp.gc record
    add_srv_record(samdb, forest_container_dn, "DC=_ldap._tcp.gc",
            fqdn_hostname, 3268)

    # DC=_ldap._tcp.pdc record
    add_srv_record(samdb, forest_container_dn, "DC=_ldap._tcp.pdc",
            fqdn_hostname, 389)

    # DC=gc record
    add_host_record(samdb, forest_container_dn, "DC=gc", hostip, hostip6)

    # DC=_ldap._tcp.<DOMAINGUID>.domains record
    add_srv_record(samdb, forest_container_dn,
            "DC=_ldap._tcp.%s.domains" % domainguid, fqdn_hostname, 389)

    # DC=<NTDSGUID>
    add_cname_record(samdb, forest_container_dn, "DC=%s" % ntdsguid,
            fqdn_hostname)


def secretsdb_setup_dns(secretsdb, names, private_dir, realm,
                        dnsdomain, dns_keytab_path, dnspass, key_version_number):
    """Add DNS specific bits to a secrets database.

    :param secretsdb: Ldb Handle to the secrets database
    :param names: Names shortcut
    :param machinepass: Machine password
    """
    try:
        os.unlink(os.path.join(private_dir, dns_keytab_path))
    except OSError:
        pass

    if key_version_number is None:
        key_version_number = 1

    setup_ldb(secretsdb, setup_path("secrets_dns.ldif"), {
            "REALM": realm,
            "DNSDOMAIN": dnsdomain,
            "DNS_KEYTAB": dns_keytab_path,
            "DNSPASS_B64": b64encode(dnspass),
            "KEY_VERSION_NUMBER": str(key_version_number),
            "HOSTNAME": names.hostname,
            "DNSNAME" : '%s.%s' % (
                names.netbiosname.lower(), names.dnsdomain.lower())
            })


def create_dns_dir(logger, paths):
    """Write out a DNS zone file, from the info in the current database.

    :param logger: Logger object
    :param paths: paths object
    """
    dns_dir = os.path.dirname(paths.dns)

    try:
        shutil.rmtree(dns_dir, True)
    except OSError:
        pass

    os.mkdir(dns_dir, 0770)

    if paths.bind_gid is not None:
        try:
            os.chown(dns_dir, -1, paths.bind_gid)
            # chmod needed to cope with umask
            os.chmod(dns_dir, 0770)
        except OSError:
            if not os.environ.has_key('SAMBA_SELFTEST'):
                logger.error("Failed to chown %s to bind gid %u" % (
                    dns_dir, paths.bind_gid))


def create_zone_file(lp, logger, paths, targetdir, dnsdomain,
                     hostip, hostip6, hostname, realm, domainguid,
                     ntdsguid, site):
    """Write out a DNS zone file, from the info in the current database.

    :param paths: paths object
    :param dnsdomain: DNS Domain name
    :param domaindn: DN of the Domain
    :param hostip: Local IPv4 IP
    :param hostip6: Local IPv6 IP
    :param hostname: Local hostname
    :param realm: Realm name
    :param domainguid: GUID of the domain.
    :param ntdsguid: GUID of the hosts nTDSDSA record.
    """
    assert isinstance(domainguid, str)

    if hostip6 is not None:
        hostip6_base_line = "            IN AAAA    " + hostip6
        hostip6_host_line = hostname + "        IN AAAA    " + hostip6
        gc_msdcs_ip6_line = "gc._msdcs               IN AAAA    " + hostip6
    else:
        hostip6_base_line = ""
        hostip6_host_line = ""
        gc_msdcs_ip6_line = ""

    if hostip is not None:
        hostip_base_line = "            IN A    " + hostip
        hostip_host_line = hostname + "        IN A    " + hostip
        gc_msdcs_ip_line = "gc._msdcs               IN A    " + hostip
    else:
        hostip_base_line = ""
        hostip_host_line = ""
        gc_msdcs_ip_line = ""

    # we need to freeze the zone while we update the contents
    if targetdir is None:
        rndc = ' '.join(lp.get("rndc command"))
        os.system(rndc + " freeze " + lp.get("realm"))

    setup_file(setup_path("provision.zone"), paths.dns, {
            "HOSTNAME": hostname,
            "DNSDOMAIN": dnsdomain,
            "REALM": realm,
            "HOSTIP_BASE_LINE": hostip_base_line,
            "HOSTIP_HOST_LINE": hostip_host_line,
            "DOMAINGUID": domainguid,
            "DATESTRING": time.strftime("%Y%m%d%H"),
            "DEFAULTSITE": site,
            "NTDSGUID": ntdsguid,
            "HOSTIP6_BASE_LINE": hostip6_base_line,
            "HOSTIP6_HOST_LINE": hostip6_host_line,
            "GC_MSDCS_IP_LINE": gc_msdcs_ip_line,
            "GC_MSDCS_IP6_LINE": gc_msdcs_ip6_line,
        })

    if paths.bind_gid is not None:
        try:
            os.chown(paths.dns, -1, paths.bind_gid)
            # chmod needed to cope with umask
            os.chmod(paths.dns, 0664)
        except OSError:
            if not os.environ.has_key('SAMBA_SELFTEST'):
                logger.error("Failed to chown %s to bind gid %u" % (
                    paths.dns, paths.bind_gid))

    if targetdir is None:
        os.system(rndc + " unfreeze " + lp.get("realm"))


def create_samdb_copy(samdb, logger, paths, names, domainsid, domainguid):
    """Create a copy of samdb and give write permissions to named for dns partitions
    """
    private_dir = paths.private_dir
    samldb_dir = os.path.join(private_dir, "sam.ldb.d")
    dns_dir = os.path.dirname(paths.dns)
    dns_samldb_dir = os.path.join(dns_dir, "sam.ldb.d")

    # Find the partitions and corresponding filenames
    partfile = {}
    res = samdb.search(base="@PARTITION", scope=ldb.SCOPE_BASE, attrs=["partition"])
    for tmp in res[0]["partition"]:
        (nc, fname) = tmp.split(':')
        partfile[nc.upper()] = fname

    # Create empty domain partition
    domaindn = names.domaindn.upper()
    domainpart_file = os.path.join(dns_dir, partfile[domaindn])
    try:
        os.mkdir(dns_samldb_dir)
        file(domainpart_file, 'w').close()

        # Fill the basedn and @OPTION records in domain partition
        dom_ldb = samba.Ldb(domainpart_file)
        domainguid_line = "objectGUID: %s\n-" % domainguid
        descr = b64encode(get_domain_descriptor(domainsid))
        setup_add_ldif(dom_ldb, setup_path("provision_basedn.ldif"), {
            "DOMAINDN" : names.domaindn,
            "DOMAINGUID" : domainguid_line,
            "DOMAINSID" : str(domainsid),
            "DESCRIPTOR" : descr})
        setup_add_ldif(dom_ldb,
            setup_path("provision_basedn_options.ldif"), None)
    except:
        logger.error(
            "Failed to setup database for BIND, AD based DNS cannot be used")
        raise

    # This line is critical to the security of the whole scheme.
    # We assume there is no secret data in the (to be left out of
    # date and essentially read-only) config, schema and metadata partitions.
    #
    # Only the stub of the domain partition is created above.
    #
    # That way, things like the krbtgt key do not leak.
    del partfile[domaindn]

    # Link dns partitions and metadata
    domainzonedn = "DC=DOMAINDNSZONES,%s" % names.domaindn.upper()
    forestzonedn = "DC=FORESTDNSZONES,%s" % names.rootdn.upper()

    domainzone_file = partfile[domainzonedn]
    forestzone_file = partfile.get(forestzonedn)

    metadata_file = "metadata.tdb"
    try:
        os.link(os.path.join(samldb_dir, metadata_file),
            os.path.join(dns_samldb_dir, metadata_file))
        os.link(os.path.join(private_dir, domainzone_file),
            os.path.join(dns_dir, domainzone_file))
        if forestzone_file:
            os.link(os.path.join(private_dir, forestzone_file),
                    os.path.join(dns_dir, forestzone_file))
    except OSError:
        logger.error(
            "Failed to setup database for BIND, AD based DNS cannot be used")
        raise
    del partfile[domainzonedn]
    if forestzone_file:
        del partfile[forestzonedn]

    # Copy root, config, schema partitions (and any other if any)
    # Since samdb is open in the current process, copy them in a child process
    try:
        tdb_copy(os.path.join(private_dir, "sam.ldb"),
                 os.path.join(dns_dir, "sam.ldb"))
        for nc in partfile:
            pfile = partfile[nc]
            tdb_copy(os.path.join(private_dir, pfile),
                     os.path.join(dns_dir, pfile))
    except:
        logger.error(
            "Failed to setup database for BIND, AD based DNS cannot be used")
        raise

    # Give bind read/write permissions dns partitions
    if paths.bind_gid is not None:
        try:
            os.chown(samldb_dir, -1, paths.bind_gid)
            os.chmod(samldb_dir, 0750)

            for dirname, dirs, files in os.walk(dns_dir):
                for d in dirs:
                    dpath = os.path.join(dirname, d)
                    os.chown(dpath, -1, paths.bind_gid)
                    os.chmod(dpath, 0770)
                for f in files:
                    if f.endswith('.ldb') or f.endswith('.tdb'):
                        fpath = os.path.join(dirname, f)
                        os.chown(fpath, -1, paths.bind_gid)
                        os.chmod(fpath, 0660)
        except OSError:
            if not os.environ.has_key('SAMBA_SELFTEST'):
                logger.error(
                    "Failed to set permissions to sam.ldb* files, fix manually")
    else:
        if not os.environ.has_key('SAMBA_SELFTEST'):
            logger.warning("""Unable to find group id for BIND,
                set permissions to sam.ldb* files manually""")


def create_dns_update_list(lp, logger, paths):
    """Write out a dns_update_list file"""
    # note that we use no variable substitution on this file
    # the substitution is done at runtime by samba_dnsupdate, samba_spnupdate
    setup_file(setup_path("dns_update_list"), paths.dns_update_list, None)
    setup_file(setup_path("spn_update_list"), paths.spn_update_list, None)


def create_named_conf(paths, realm, dnsdomain, dns_backend, logger):
    """Write out a file containing zone statements suitable for inclusion in a
    named.conf file (including GSS-TSIG configuration).

    :param paths: all paths
    :param realm: Realm name
    :param dnsdomain: DNS Domain name
    :param dns_backend: DNS backend type
    :param keytab_name: File name of DNS keytab file
    :param logger: Logger object
    """

    # TODO: This really should have been done as a top level import.
    # It is done here to avoid a depencency loop.  That is, we move
    # ProvisioningError to another file, and have all the provision
    # scripts import it from there.

    from samba.provision import ProvisioningError

    if dns_backend == "BIND9_FLATFILE":
        setup_file(setup_path("named.conf"), paths.namedconf, {
                    "DNSDOMAIN": dnsdomain,
                    "REALM": realm,
                    "ZONE_FILE": paths.dns,
                    "REALM_WC": "*." + ".".join(realm.split(".")[1:]),
                    "NAMED_CONF": paths.namedconf,
                    "NAMED_CONF_UPDATE": paths.namedconf_update
                    })

        setup_file(setup_path("named.conf.update"), paths.namedconf_update)

    elif dns_backend == "BIND9_DLZ":
        bind_info = subprocess.Popen(['named -V'], shell=True,
                                     stdout=subprocess.PIPE,
                                     stderr=subprocess.STDOUT,
                                     cwd='.').communicate()[0]
        bind9_8 = '#'
        bind9_9 = '#'
        bind9_10 = '#'
        if bind_info.upper().find('BIND 9.8') != -1:
            bind9_8 = ''
        elif bind_info.upper().find('BIND 9.9') != -1:
            bind9_9 = ''
        elif bind_info.upper().find('BIND 9.10') != -1:
            bind9_10 = ''
        elif bind_info.upper().find('BIND 9.7') != -1:
            raise ProvisioningError("DLZ option incompatible with BIND 9.7.")
        else:
            logger.warning("BIND version unknown, please modify %s manually." % paths.namedconf)
        setup_file(setup_path("named.conf.dlz"), paths.namedconf, {
                    "NAMED_CONF": paths.namedconf,
                    "MODULESDIR" : samba.param.modules_dir(),
                    "BIND9_8" : bind9_8,
                    "BIND9_9" : bind9_9,
                    "BIND9_10" : bind9_10
                    })


def create_named_txt(path, realm, dnsdomain, dnsname, private_dir,
    keytab_name):
    """Write out a file containing zone statements suitable for inclusion in a
    named.conf file (including GSS-TSIG configuration).

    :param path: Path of the new named.conf file.
    :param realm: Realm name
    :param dnsdomain: DNS Domain name
    :param private_dir: Path to private directory
    :param keytab_name: File name of DNS keytab file
    """
    setup_file(setup_path("named.txt"), path, {
            "DNSDOMAIN": dnsdomain,
            "DNSNAME" : dnsname,
            "REALM": realm,
            "DNS_KEYTAB": keytab_name,
            "DNS_KEYTAB_ABS": os.path.join(private_dir, keytab_name),
            "PRIVATE_DIR": private_dir
        })


def is_valid_dns_backend(dns_backend):
    return dns_backend in ("BIND9_FLATFILE", "BIND9_DLZ", "SAMBA_INTERNAL", "NONE")


def is_valid_os_level(os_level):
    return DS_DOMAIN_FUNCTION_2000 <= os_level <= DS_DOMAIN_FUNCTION_2012_R2


def create_dns_legacy(samdb, domainsid, forestdn, dnsadmins_sid):
    # Set up MicrosoftDNS container
    add_dns_container(samdb, forestdn, "CN=System", domainsid, dnsadmins_sid)
    # Add root servers
    add_rootservers(samdb, forestdn, "CN=System")


def fill_dns_data_legacy(samdb, domainsid, forestdn, dnsdomain, site, hostname,
                         hostip, hostip6, dnsadmins_sid):
    # Add domain record
    add_domain_record(samdb, forestdn, "CN=System", dnsdomain, domainsid,
                      dnsadmins_sid)

    # Add DNS records for a DC in domain
    add_dc_domain_records(samdb, forestdn, "CN=System", site, dnsdomain,
                          hostname, hostip, hostip6)


def create_dns_partitions(samdb, domainsid, names, domaindn, forestdn,
                          dnsadmins_sid, fill_level):
    # Set up additional partitions (DomainDnsZones, ForstDnsZones)
    setup_dns_partitions(samdb, domainsid, domaindn, forestdn,
                        names.configdn, names.serverdn, fill_level)

    # Set up MicrosoftDNS containers
    add_dns_container(samdb, domaindn, "DC=DomainDnsZones", domainsid,
                      dnsadmins_sid)
    if fill_level != FILL_SUBDOMAIN:
        add_dns_container(samdb, forestdn, "DC=ForestDnsZones", domainsid,
                          dnsadmins_sid, forest=True)


def fill_dns_data_partitions(samdb, domainsid, site, domaindn, forestdn,
                             dnsdomain, dnsforest, hostname, hostip, hostip6,
                             domainguid, ntdsguid, dnsadmins_sid, autofill=True,
                             fill_level=FILL_FULL):
    """Fill data in various AD partitions

    :param samdb: LDB object connected to sam.ldb file
    :param domainsid: Domain SID (as dom_sid object)
    :param site: Site name to create hostnames in
    :param domaindn: DN of the domain
    :param forestdn: DN of the forest
    :param dnsdomain: DNS name of the domain
    :param dnsforest: DNS name of the forest
    :param hostname: Host name of this DC
    :param hostip: IPv4 addresses
    :param hostip6: IPv6 addresses
    :param domainguid: Domain GUID
    :param ntdsguid: NTDS GUID
    :param dnsadmins_sid: SID for DnsAdmins group
    :param autofill: Create DNS records (using fixed template)
    """

    ##### Set up DC=DomainDnsZones,<DOMAINDN>
    # Add rootserver records
    add_rootservers(samdb, domaindn, "DC=DomainDnsZones")

    # Add domain record
    add_domain_record(samdb, domaindn, "DC=DomainDnsZones", dnsdomain,
                      domainsid, dnsadmins_sid)

    # Add DNS records for a DC in domain
    if autofill:
        add_dc_domain_records(samdb, domaindn, "DC=DomainDnsZones", site,
                              dnsdomain, hostname, hostip, hostip6)

    if fill_level != FILL_SUBDOMAIN:
        ##### Set up DC=ForestDnsZones,<FORESTDN>
        # Add _msdcs record
        add_msdcs_record(samdb, forestdn, "DC=ForestDnsZones", dnsforest)

        # Add DNS records for a DC in forest
        if autofill:
            add_dc_msdcs_records(samdb, forestdn, "DC=ForestDnsZones", site,
                                 dnsforest, hostname, hostip, hostip6,
                                 domainguid, ntdsguid)


def setup_ad_dns(samdb, secretsdb, names, paths, lp, logger,
        dns_backend, os_level, dnspass=None, hostip=None, hostip6=None,
        targetdir=None, fill_level=FILL_FULL):
    """Provision DNS information (assuming GC role)

    :param samdb: LDB object connected to sam.ldb file
    :param secretsdb: LDB object connected to secrets.ldb file
    :param names: Names shortcut
    :param paths: Paths shortcut
    :param lp: Loadparm object
    :param logger: Logger object
    :param dns_backend: Type of DNS backend
    :param os_level: Functional level (treated as os level)
    :param dnspass: Password for bind's DNS account
    :param hostip: IPv4 address
    :param hostip6: IPv6 address
    :param targetdir: Target directory for creating DNS-related files for BIND9
    """

    if not is_valid_dns_backend(dns_backend):
        raise Exception("Invalid dns backend: %r" % dns_backend)

    if not is_valid_os_level(os_level):
        raise Exception("Invalid os level: %r" % os_level)

    if dns_backend == "NONE":
        logger.info("No DNS backend set, not configuring DNS")
        return

    # Add dns accounts (DnsAdmins, DnsUpdateProxy) in domain
    logger.info("Adding DNS accounts")
    add_dns_accounts(samdb, names.domaindn)

    # If dns_backend is BIND9_FLATFILE
    #   Populate only CN=MicrosoftDNS,CN=System,<DOMAINDN>
    #
    # If dns_backend is SAMBA_INTERNAL or BIND9_DLZ
    #   Populate DNS partitions

    # If os_level < 2003 (DS_DOMAIN_FUNCTION_2000)
    #   All dns records are in CN=MicrosoftDNS,CN=System,<DOMAINDN>
    #
    # If os_level >= 2003 (DS_DOMAIN_FUNCTION_2003, DS_DOMAIN_FUNCTION_2008,
    #                        DS_DOMAIN_FUNCTION_2008_R2)
    #   Root server records are in CN=MicrosoftDNS,CN=System,<DOMAINDN>
    #   Domain records are in CN=MicrosoftDNS,CN=System,<DOMAINDN>
    #   Domain records are in CN=MicrosoftDNS,DC=DomainDnsZones,<DOMAINDN>
    #   Forest records are in CN=MicrosoftDNS,DC=ForestDnsZones,<FORESTDN>
    domaindn = names.domaindn
    forestdn = samdb.get_root_basedn().get_linearized()

    dnsdomain = names.dnsdomain.lower()
    dnsforest = dnsdomain

    site = names.sitename

    hostname = names.netbiosname.lower()

    dnsadmins_sid = get_dnsadmins_sid(samdb, domaindn)
    domainguid = get_domainguid(samdb, domaindn)

    # Create CN=System
    logger.info("Creating CN=MicrosoftDNS,CN=System,%s" % domaindn)
    create_dns_legacy(samdb, names.domainsid, domaindn, dnsadmins_sid)

    if os_level == DS_DOMAIN_FUNCTION_2000:
        # Populating legacy dns
        logger.info("Populating CN=MicrosoftDNS,CN=System,%s" % domaindn)
        fill_dns_data_legacy(samdb, names.domainsid, domaindn, dnsdomain, site,
                             hostname, hostip, hostip6, dnsadmins_sid)

    elif dns_backend in ("SAMBA_INTERNAL", "BIND9_DLZ") and \
            os_level >= DS_DOMAIN_FUNCTION_2003:

        # Create DNS partitions
        logger.info("Creating DomainDnsZones and ForestDnsZones partitions")
        create_dns_partitions(samdb, names.domainsid, names, domaindn, forestdn,
                              dnsadmins_sid, fill_level)

        # Populating dns partitions
        logger.info("Populating DomainDnsZones and ForestDnsZones partitions")
        fill_dns_data_partitions(samdb, names.domainsid, site, domaindn, forestdn,
                                 dnsdomain, dnsforest, hostname, hostip, hostip6,
                                 domainguid, names.ntdsguid, dnsadmins_sid,
                                 fill_level=fill_level)

    if dns_backend.startswith("BIND9_"):
        setup_bind9_dns(samdb, secretsdb, names, paths, lp, logger,
                        dns_backend, os_level, site=site, dnspass=dnspass, hostip=hostip,
                        hostip6=hostip6, targetdir=targetdir)


def setup_bind9_dns(samdb, secretsdb, names, paths, lp, logger,
        dns_backend, os_level, site=None, dnspass=None, hostip=None,
        hostip6=None, targetdir=None, key_version_number=None):
    """Provision DNS information (assuming BIND9 backend in DC role)

    :param samdb: LDB object connected to sam.ldb file
    :param secretsdb: LDB object connected to secrets.ldb file
    :param names: Names shortcut
    :param paths: Paths shortcut
    :param lp: Loadparm object
    :param logger: Logger object
    :param dns_backend: Type of DNS backend
    :param os_level: Functional level (treated as os level)
    :param site: Site to create hostnames in
    :param dnspass: Password for bind's DNS account
    :param hostip: IPv4 address
    :param hostip6: IPv6 address
    :param targetdir: Target directory for creating DNS-related files for BIND9
    """

    if (not is_valid_dns_backend(dns_backend) or
        not dns_backend.startswith("BIND9_")):
        raise Exception("Invalid dns backend: %r" % dns_backend)

    if not is_valid_os_level(os_level):
        raise Exception("Invalid os level: %r" % os_level)

    domaindn = names.domaindn

    domainguid = get_domainguid(samdb, domaindn)

    secretsdb_setup_dns(secretsdb, names,
                        paths.private_dir, realm=names.realm,
                        dnsdomain=names.dnsdomain,
                        dns_keytab_path=paths.dns_keytab, dnspass=dnspass,
                        key_version_number=key_version_number)

    dns_keytab_path = os.path.join(paths.private_dir, paths.dns_keytab)
    if os.path.isfile(dns_keytab_path) and paths.bind_gid is not None:
        try:
            os.chmod(dns_keytab_path, 0640)
            os.chown(dns_keytab_path, -1, paths.bind_gid)
        except OSError:
            if not os.environ.has_key('SAMBA_SELFTEST'):
                logger.info("Failed to chown %s to bind gid %u",
                            dns_keytab_path, paths.bind_gid)

    create_dns_dir(logger, paths)

    if dns_backend == "BIND9_FLATFILE":
        create_zone_file(lp, logger, paths, targetdir, site=site,
                         dnsdomain=names.dnsdomain, hostip=hostip,
                         hostip6=hostip6, hostname=names.hostname,
                         realm=names.realm, domainguid=domainguid,
                         ntdsguid=names.ntdsguid)

    if dns_backend == "BIND9_DLZ" and os_level >= DS_DOMAIN_FUNCTION_2003:
        create_samdb_copy(samdb, logger, paths, names, names.domainsid, domainguid)

    create_named_conf(paths, realm=names.realm,
                      dnsdomain=names.dnsdomain, dns_backend=dns_backend,
                      logger=logger)

    create_named_txt(paths.namedtxt,
                     realm=names.realm, dnsdomain=names.dnsdomain,
                     dnsname = "%s.%s" % (names.hostname, names.dnsdomain),
                     private_dir=paths.private_dir,
                     keytab_name=paths.dns_keytab)
    logger.info("See %s for an example configuration include file for BIND",
                paths.namedconf)
    logger.info("and %s for further documentation required for secure DNS "
                "updates", paths.namedtxt)
