3 # update our DNS names using TSIG-GSS
5 # Copyright (C) Andrew Tridgell 2010
7 # This program is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 3 of the License, or
10 # (at your option) any later version.
12 # This program is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with this program. If not, see <http://www.gnu.org/licenses/>.
27 # ensure we get messages out immediately, so they get in the samba logs,
28 # and don't get swallowed by a timeout
29 os.putenv('PYTHONUNBUFFERED', '1')
31 # forcing GMT avoids a problem in some timezones with kerberos. Both MIT
32 # heimdal can get mutual authentication errors due to the 24 second difference
33 # between UTC and GMT when using some zone files (eg. the PDT zone from
35 os.putenv("TZ", "GMT")
37 # Find right directory when running from source tree
38 sys.path.insert(0, "bin/python")
42 from samba import getopt as options
43 from ldb import SCOPE_BASE
44 from samba.auth import system_session
45 from samba.samdb import SamDB
46 from samba.dcerpc import netlogon, winbind
48 samba.ensure_external_module("dns", "dnspython")
49 import dns.resolver as resolver
55 parser = optparse.OptionParser("samba_dnsupdate")
56 sambaopts = options.SambaOptions(parser)
57 parser.add_option_group(sambaopts)
58 parser.add_option_group(options.VersionOptions(parser))
59 parser.add_option("--verbose", action="store_true")
60 parser.add_option("--all-names", action="store_true")
61 parser.add_option("--all-interfaces", action="store_true")
62 parser.add_option("--use-file", type="string", help="Use a file, rather than real DNS calls")
63 parser.add_option("--update-list", type="string", help="Add DNS names from the given file")
64 parser.add_option("--fail-immediately", action='store_true', help="Exit on first failure")
69 opts, args = parser.parse_args()
75 lp = sambaopts.get_loadparm()
77 domain = lp.get("realm")
78 host = lp.get("netbios name")
79 if opts.all_interfaces:
82 all_interfaces = False
84 IPs = samba.interface_ips(lp, all_interfaces)
85 nsupdate_cmd = lp.get('nsupdate command')
88 print "No IP interfaces - skipping DNS updates"
94 ########################################################
95 # get credentials if we haven't got them already
96 def get_credentials(lp):
97 from samba import credentials
98 global ccachename, creds
101 creds = credentials.Credentials()
103 creds.set_machine_account(lp)
104 creds.set_krb_forwardable(credentials.NO_KRB_FORWARDABLE)
105 (tmp_fd, ccachename) = tempfile.mkstemp()
106 creds.get_named_ccache(lp, ccachename)
109 #############################################
110 # an object to hold a parsed DNS line
111 class dnsobj(object):
112 def __init__(self, string_form):
113 list = string_form.split()
117 self.existing_port = None
118 self.existing_weight = None
120 self.name = list[1].lower()
121 if self.type == 'SRV':
122 self.dest = list[2].lower()
124 elif self.type == 'A':
125 self.ip = list[2] # usually $IP, which gets replaced
126 elif self.type == 'CNAME':
127 self.dest = list[2].lower()
129 print "Received unexpected DNS reply of type %s" % self.type
133 if d.type == "A": return "%s %s %s" % (self.type, self.name, self.ip)
134 if d.type == "SRV": return "%s %s %s %s" % (self.type, self.name, self.dest, self.port)
135 if d.type == "CNAME": return "%s %s %s" % (self.type, self.name, self.dest)
138 ################################################
139 # parse a DNS line from
140 def parse_dns_line(line, sub_vars):
141 subline = samba.substitute_var(line, sub_vars)
145 ############################################
146 # see if two hostnames match
147 def hostname_match(h1, h2):
150 return h1.lower().rstrip('.') == h2.lower().rstrip('.')
153 ############################################
154 # check that a DNS entry exists
155 def check_dns_name(d):
156 normalised_name = d.name.rstrip('.') + '.'
158 print "Looking for DNS entry %s as %s" % (d, normalised_name)
160 if opts.use_file is not None:
162 dns_file = open(opts.use_file, "r")
166 for line in dns_file:
168 if line == '' or line[0] == "#":
170 if line.lower() == str(d).lower():
175 ans = resolver.query(normalised_name, d.type)
176 except resolver.NXDOMAIN:
179 # we need to be sure that our IP is there
181 if str(rdata) == str(d.ip):
183 if d.type == 'CNAME':
184 for i in range(len(ans)):
185 if hostname_match(ans[i].target, d.dest):
190 print "Checking %s against %s" % (rdata, d)
191 if hostname_match(rdata.target, d.dest):
192 if str(rdata.port) == str(d.port):
195 d.existing_port = str(rdata.port)
196 d.existing_weight = str(rdata.weight)
198 print "Failed to find DNS entry %s" % d
203 ###########################################
204 # get the list of substitution vars
205 def get_subst_vars():
209 samdb = SamDB(url=lp.get("sam database"), session_info=system_session(),
212 vars['DNSDOMAIN'] = lp.get('realm').lower()
213 vars['DNSFOREST'] = lp.get('realm').lower()
214 vars['HOSTNAME'] = lp.get('netbios name').lower() + "." + vars['DNSDOMAIN']
215 vars['NTDSGUID'] = samdb.get_ntds_GUID()
216 vars['SITE'] = samdb.server_site_name()
217 res = samdb.search(base=None, scope=SCOPE_BASE, attrs=["objectGUID"])
218 guid = samdb.schema_format_value("objectGUID", res[0]['objectGUID'][0])
219 vars['DOMAINGUID'] = guid
220 am_rodc = samdb.am_rodc()
225 ############################################
226 # call nsupdate for an entry
227 def call_nsupdate(d):
228 global ccachename, nsupdate_cmd
231 print "Calling nsupdate for %s" % d
233 if opts.use_file is not None:
234 wfile = open(opts.use_file, 'a')
235 fcntl.lockf(wfile, fcntl.LOCK_EX)
236 wfile.write(str(d)+"\n")
237 fcntl.lockf(wfile, fcntl.LOCK_UN)
240 normalised_name = d.name.rstrip('.') + '.'
242 (tmp_fd, tmpfile) = tempfile.mkstemp()
243 f = os.fdopen(tmp_fd, 'w')
245 f.write("update add %s %u A %s\n" % (normalised_name, default_ttl, d.ip))
247 if d.existing_port is not None:
248 f.write("update delete %s SRV 0 %s %s %s\n" % (normalised_name, d.existing_weight,
249 d.existing_port, d.dest))
250 f.write("update add %s %u SRV 0 100 %s %s\n" % (normalised_name, default_ttl, d.port, d.dest))
251 if d.type == "CNAME":
252 f.write("update add %s %u CNAME %s\n" % (normalised_name, default_ttl, d.dest))
258 os.putenv("KRB5CCNAME", ccachename)
260 cmd = "%s %s" % (nsupdate_cmd, tmpfile)
261 subprocess.check_call(cmd, shell=True)
262 except subprocess.CalledProcessError:
264 if opts.fail_immediately:
266 error_count = error_count + 1
271 def rodc_dns_update(d, t):
272 '''a single DNS update via the RODC netlogon call'''
276 print "Calling netlogon RODC update for %s" % d
279 netlogon.NlDnsLdapAtSite : netlogon.NlDnsInfoTypeNone,
280 netlogon.NlDnsGcAtSite : netlogon.NlDnsDomainNameAlias,
281 netlogon.NlDnsDsaCname : netlogon.NlDnsDomainNameAlias,
282 netlogon.NlDnsKdcAtSite : netlogon.NlDnsInfoTypeNone,
283 netlogon.NlDnsDcAtSite : netlogon.NlDnsInfoTypeNone,
284 netlogon.NlDnsRfc1510KdcAtSite : netlogon.NlDnsInfoTypeNone,
285 netlogon.NlDnsGenericGcAtSite : netlogon.NlDnsDomainNameAlias
288 w = winbind.winbind("irpc:winbind_server", lp)
289 dns_names = netlogon.NL_DNS_NAME_INFO_ARRAY()
291 name = netlogon.NL_DNS_NAME_INFO()
293 name.dns_domain_info_type = typemap[t]
296 if d.port is not None:
297 name.port = int(d.port)
298 name.dns_register = True
299 dns_names.names = [ name ]
300 site_name = sub_vars['SITE'].decode('utf-8')
303 ret_names = w.DsrUpdateReadOnlyServerDnsRecords(site_name, default_ttl, dns_names)
304 if ret_names.names[0].status != 0:
305 print("Failed to set DNS entry: %s (status %u)" % (d, ret_names.names[0].status))
306 except RuntimeError, reason:
307 print("Error setting DNS entry of type %u: %s: %s" % (t, d, reason))
310 def call_rodc_update(d):
311 '''RODCs need to use the netlogon API for nsupdate'''
314 # we expect failure for 3268 if we aren't a GC
315 if d.port is not None and int(d.port) == 3268:
318 # map the DNS request to a netlogon update type
320 netlogon.NlDnsLdapAtSite : '_ldap._tcp.${SITE}._sites.${DNSDOMAIN}',
321 netlogon.NlDnsGcAtSite : '_ldap._tcp.${SITE}._sites.gc._msdcs.${DNSDOMAIN}',
322 netlogon.NlDnsDsaCname : '${NTDSGUID}._msdcs.${DNSFOREST}',
323 netlogon.NlDnsKdcAtSite : '_kerberos._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
324 netlogon.NlDnsDcAtSite : '_ldap._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
325 netlogon.NlDnsRfc1510KdcAtSite : '_kerberos._tcp.${SITE}._sites.${DNSDOMAIN}',
326 netlogon.NlDnsGenericGcAtSite : '_gc._tcp.${SITE}._sites.${DNSFOREST}'
330 subname = samba.substitute_var(map[t], sub_vars)
331 if subname.lower() == d.name.lower():
332 # found a match - do the update
333 rodc_dns_update(d, t)
336 print("Unable to map to netlogon DNS update: %s" % d)
339 # get the list of DNS entries we should have
341 dns_update_list = opts.update_list
343 dns_update_list = lp.private_path('dns_update_list')
345 # use our private krb5.conf to avoid problems with the wrong domain
346 # bind9 nsupdate wants the default domain set
347 krb5conf = lp.private_path('krb5.conf')
348 os.putenv('KRB5_CONFIG', krb5conf)
350 file = open(dns_update_list, "r")
352 # get the substitution dictionary
353 sub_vars = get_subst_vars()
355 # build up a list of update commands to pass to nsupdate
359 # read each line, and check that the DNS name exists
362 if line == '' or line[0] == "#":
364 d = parse_dns_line(line, sub_vars)
367 # now expand the entries, if any are A record with ip set to $IP
368 # then replace with multiple entries, one for each interface IP
370 if d.type == 'A' and d.ip == "$IP":
372 for i in range(len(IPs)-1):
377 # now check if the entries already exist on the DNS server
379 if opts.all_names or not check_dns_name(d):
380 update_list.append(d)
382 if len(update_list) == 0:
384 print "No DNS updates needed"
390 # ask nsupdate to add entries as needed
391 for d in update_list:
393 if d.name.lower() == domain.lower():
402 # delete the ccache if we created it
403 if ccachename is not None:
404 os.unlink(ccachename)
406 sys.exit(error_count)