4 # update our DNS names using TSIG-GSS
6 # Copyright (C) Andrew Tridgell 2010
8 # This program is free software; you can redistribute it and/or modify
9 # it under the terms of the GNU General Public License as published by
10 # the Free Software Foundation; either version 3 of the License, or
11 # (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program. If not, see <http://www.gnu.org/licenses/>.
28 # ensure we get messages out immediately, so they get in the samba logs,
29 # and don't get swallowed by a timeout
30 os.environ['PYTHONUNBUFFERED'] = '1'
32 # forcing GMT avoids a problem in some timezones with kerberos. Both MIT
33 # heimdal can get mutual authentication errors due to the 24 second difference
34 # between UTC and GMT when using some zone files (eg. the PDT zone from
36 os.environ["TZ"] = "GMT"
38 # Find right directory when running from source tree
39 sys.path.insert(0, "bin/python")
43 from samba import getopt as options
44 from ldb import SCOPE_BASE
45 from samba.auth import system_session
46 from samba.samdb import SamDB
47 from samba.dcerpc import netlogon, winbind
49 samba.ensure_external_module("dns", "dnspython")
57 parser = optparse.OptionParser("samba_dnsupdate")
58 sambaopts = options.SambaOptions(parser)
59 parser.add_option_group(sambaopts)
60 parser.add_option_group(options.VersionOptions(parser))
61 parser.add_option("--verbose", action="store_true")
62 parser.add_option("--all-names", action="store_true")
63 parser.add_option("--all-interfaces", action="store_true")
64 parser.add_option("--use-file", type="string", help="Use a file, rather than real DNS calls")
65 parser.add_option("--update-list", type="string", help="Add DNS names from the given file")
66 parser.add_option("--fail-immediately", action='store_true', help="Exit on first failure")
67 parser.add_option("--no-credentials", dest='nocreds', action='store_true', help="don't try and get credentials")
68 parser.add_option("--no-substiutions", dest='nosubs', action='store_true', help="don't try and expands variables in file specified by --update-list")
73 opts, args = parser.parse_args()
79 lp = sambaopts.get_loadparm()
81 domain = lp.get("realm")
82 host = lp.get("netbios name")
83 if opts.all_interfaces:
86 all_interfaces = False
88 IPs = samba.interface_ips(lp, all_interfaces)
89 nsupdate_cmd = lp.get('nsupdate command')
92 print "No IP interfaces - skipping DNS updates"
105 print "IPs: %s" % IPs
108 def get_credentials(lp):
109 """# get credentials if we haven't got them already."""
110 from samba import credentials
111 global ccachename, creds
112 if creds is not None:
114 creds = credentials.Credentials()
116 creds.set_machine_account(lp)
117 creds.set_krb_forwardable(credentials.NO_KRB_FORWARDABLE)
118 (tmp_fd, ccachename) = tempfile.mkstemp()
120 creds.get_named_ccache(lp, ccachename)
121 except RuntimeError as e:
122 os.unlink(ccachename)
126 class dnsobj(object):
127 """an object to hold a parsed DNS line"""
129 def __init__(self, string_form):
130 list = string_form.split()
132 raise Exception("Invalid DNS entry %r" % string_form)
136 self.existing_port = None
137 self.existing_weight = None
139 self.name = list[1].lower()
140 if self.type == 'SRV':
142 raise Exception("Invalid DNS entry %r" % string_form)
143 self.dest = list[2].lower()
145 elif self.type in ['A', 'AAAA']:
146 self.ip = list[2] # usually $IP, which gets replaced
147 elif self.type == 'CNAME':
148 self.dest = list[2].lower()
149 elif self.type == 'NS':
150 self.dest = list[2].lower()
152 raise Exception("Received unexpected DNS reply of type %s" % self.type)
156 return "%s %s %s" % (self.type, self.name, self.ip)
158 return "%s %s %s" % (self.type, self.name, self.ip)
160 return "%s %s %s %s" % (self.type, self.name, self.dest, self.port)
161 if d.type == "CNAME":
162 return "%s %s %s" % (self.type, self.name, self.dest)
164 return "%s %s %s" % (self.type, self.name, self.dest)
167 def parse_dns_line(line, sub_vars):
168 """parse a DNS line from."""
169 if line.startswith("SRV _ldap._tcp.pdc._msdcs.") and not samdb.am_pdc():
171 print "Skipping PDC entry (%s) as we are not a PDC" % line
173 subline = samba.substitute_var(line, sub_vars)
174 return dnsobj(subline)
177 def hostname_match(h1, h2):
178 """see if two hostnames match."""
181 return h1.lower().rstrip('.') == h2.lower().rstrip('.')
184 def check_dns_name(d):
185 """check that a DNS entry exists."""
186 normalised_name = d.name.rstrip('.') + '.'
188 print "Looking for DNS entry %s as %s" % (d, normalised_name)
190 if opts.use_file is not None:
192 dns_file = open(opts.use_file, "r")
196 for line in dns_file:
198 if line == '' or line[0] == "#":
200 if line.lower() == str(d).lower():
204 resolver = dns.resolver.Resolver()
206 # we need to lookup the nameserver for the parent domain,
207 # and use that to check the NS record
208 parent_domain = '.'.join(normalised_name.split('.')[1:])
210 ans = resolver.query(parent_domain, 'NS')
211 except dns.exception.DNSException:
213 print "Failed to find parent NS for %s" % d
216 for i in range(len(ans)):
218 ns = resolver.query(str(ans[i]), 'A')
219 except dns.exception.DNSException:
221 for j in range(len(ns)):
222 nameservers.add(str(ns[j]))
223 d.nameservers = list(nameservers)
226 if getattr(d, 'nameservers', None):
227 resolver.nameservers = list(d.nameservers)
228 ans = resolver.query(normalised_name, d.type)
229 except dns.exception.DNSException:
231 print "Failed to find DNS entry %s" % d
233 if d.type in ['A', 'AAAA']:
234 # we need to be sure that our IP is there
236 if str(rdata) == str(d.ip):
238 elif d.type == 'CNAME':
239 for i in range(len(ans)):
240 if hostname_match(ans[i].target, d.dest):
243 for i in range(len(ans)):
244 if hostname_match(ans[i].target, d.dest):
246 elif d.type == 'SRV':
249 print "Checking %s against %s" % (rdata, d)
250 if hostname_match(rdata.target, d.dest):
251 if str(rdata.port) == str(d.port):
254 d.existing_port = str(rdata.port)
255 d.existing_weight = str(rdata.weight)
258 print "Failed to find matching DNS entry %s" % d
263 def get_subst_vars(samdb):
264 """get the list of substitution vars."""
268 vars['DNSDOMAIN'] = samdb.domain_dns_name()
269 vars['DNSFOREST'] = samdb.forest_dns_name()
270 vars['HOSTNAME'] = samdb.host_dns_name()
271 vars['NTDSGUID'] = samdb.get_ntds_GUID()
272 vars['SITE'] = samdb.server_site_name()
273 res = samdb.search(base=samdb.get_default_basedn(), scope=SCOPE_BASE, attrs=["objectGUID"])
274 guid = samdb.schema_format_value("objectGUID", res[0]['objectGUID'][0])
275 vars['DOMAINGUID'] = guid
276 am_rodc = samdb.am_rodc()
281 def call_nsupdate(d):
282 """call nsupdate for an entry."""
283 global ccachename, nsupdate_cmd, krb5conf
286 print "Calling nsupdate for %s" % d
288 if opts.use_file is not None:
290 rfile = open(opts.use_file, 'r+')
293 rfile = open(opts.use_file, 'w+')
294 # Open it for reading again, in case someone else got to it first
295 rfile = open(opts.use_file, 'r+')
296 fcntl.lockf(rfile, fcntl.LOCK_EX)
297 (file_dir, file_name) = os.path.split(opts.use_file)
298 (tmp_fd, tmpfile) = tempfile.mkstemp(dir=file_dir, prefix=file_name, suffix="XXXXXX")
299 wfile = os.fdopen(tmp_fd, 'a')
303 wfile.write(str(d)+"\n")
304 os.rename(tmpfile, opts.use_file)
305 fcntl.lockf(rfile, fcntl.LOCK_UN)
308 normalised_name = d.name.rstrip('.') + '.'
310 (tmp_fd, tmpfile) = tempfile.mkstemp()
311 f = os.fdopen(tmp_fd, 'w')
312 if getattr(d, 'nameservers', None):
313 f.write('server %s\n' % d.nameservers[0])
315 f.write("update add %s %u A %s\n" % (normalised_name, default_ttl, d.ip))
317 f.write("update add %s %u AAAA %s\n" % (normalised_name, default_ttl, d.ip))
319 if d.existing_port is not None:
320 f.write("update delete %s SRV 0 %s %s %s\n" % (normalised_name, d.existing_weight,
321 d.existing_port, d.dest))
322 f.write("update add %s %u SRV 0 100 %s %s\n" % (normalised_name, default_ttl, d.port, d.dest))
323 if d.type == "CNAME":
324 f.write("update add %s %u CNAME %s\n" % (normalised_name, default_ttl, d.dest))
326 f.write("update add %s %u NS %s\n" % (normalised_name, default_ttl, d.dest))
334 os.environ["KRB5CCNAME"] = ccachename
336 cmd = nsupdate_cmd[:]
340 env["KRB5_CONFIG"] = krb5conf
342 env["KRB5CCNAME"] = ccachename
343 ret = subprocess.call(cmd, shell=False, env=env)
345 if opts.fail_immediately:
347 print("Failed update with %s" % tmpfile)
349 error_count = error_count + 1
351 print("Failed nsupdate: %d" % ret)
352 except Exception, estr:
353 if opts.fail_immediately:
355 error_count = error_count + 1
357 print("Failed nsupdate: %s : %s" % (str(d), estr))
362 def rodc_dns_update(d, t):
363 '''a single DNS update via the RODC netlogon call'''
367 print "Calling netlogon RODC update for %s" % d
370 netlogon.NlDnsLdapAtSite : netlogon.NlDnsInfoTypeNone,
371 netlogon.NlDnsGcAtSite : netlogon.NlDnsDomainNameAlias,
372 netlogon.NlDnsDsaCname : netlogon.NlDnsDomainNameAlias,
373 netlogon.NlDnsKdcAtSite : netlogon.NlDnsInfoTypeNone,
374 netlogon.NlDnsDcAtSite : netlogon.NlDnsInfoTypeNone,
375 netlogon.NlDnsRfc1510KdcAtSite : netlogon.NlDnsInfoTypeNone,
376 netlogon.NlDnsGenericGcAtSite : netlogon.NlDnsDomainNameAlias
379 w = winbind.winbind("irpc:winbind_server", lp)
380 dns_names = netlogon.NL_DNS_NAME_INFO_ARRAY()
382 name = netlogon.NL_DNS_NAME_INFO()
384 name.dns_domain_info_type = typemap[t]
387 if d.port is not None:
388 name.port = int(d.port)
389 name.dns_register = True
390 dns_names.names = [ name ]
391 site_name = sub_vars['SITE'].decode('utf-8')
396 ret_names = w.DsrUpdateReadOnlyServerDnsRecords(site_name, default_ttl, dns_names)
397 if ret_names.names[0].status != 0:
398 print("Failed to set DNS entry: %s (status %u)" % (d, ret_names.names[0].status))
399 error_count = error_count + 1
400 except RuntimeError, reason:
401 print("Error setting DNS entry of type %u: %s: %s" % (t, d, reason))
402 error_count = error_count + 1
404 if error_count != 0 and opts.fail_immediately:
408 def call_rodc_update(d):
409 '''RODCs need to use the netlogon API for nsupdate'''
412 # we expect failure for 3268 if we aren't a GC
413 if d.port is not None and int(d.port) == 3268:
416 # map the DNS request to a netlogon update type
418 netlogon.NlDnsLdapAtSite : '_ldap._tcp.${SITE}._sites.${DNSDOMAIN}',
419 netlogon.NlDnsGcAtSite : '_ldap._tcp.${SITE}._sites.gc._msdcs.${DNSDOMAIN}',
420 netlogon.NlDnsDsaCname : '${NTDSGUID}._msdcs.${DNSFOREST}',
421 netlogon.NlDnsKdcAtSite : '_kerberos._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
422 netlogon.NlDnsDcAtSite : '_ldap._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
423 netlogon.NlDnsRfc1510KdcAtSite : '_kerberos._tcp.${SITE}._sites.${DNSDOMAIN}',
424 netlogon.NlDnsGenericGcAtSite : '_gc._tcp.${SITE}._sites.${DNSFOREST}'
428 subname = samba.substitute_var(map[t], sub_vars)
429 if subname.lower() == d.name.lower():
430 # found a match - do the update
431 rodc_dns_update(d, t)
434 print("Unable to map to netlogon DNS update: %s" % d)
437 # get the list of DNS entries we should have
439 dns_update_list = opts.update_list
441 dns_update_list = lp.private_path('dns_update_list')
443 # use our private krb5.conf to avoid problems with the wrong domain
444 # bind9 nsupdate wants the default domain set
445 krb5conf = lp.private_path('krb5.conf')
446 os.environ['KRB5_CONFIG'] = krb5conf
448 file = open(dns_update_list, "r")
453 samdb = SamDB(url=lp.samdb_url(), session_info=system_session(), lp=lp)
455 # get the substitution dictionary
456 sub_vars = get_subst_vars(samdb)
458 # build up a list of update commands to pass to nsupdate
464 # read each line, and check that the DNS name exists
467 if line == '' or line[0] == "#":
469 d = parse_dns_line(line, sub_vars)
472 if d.type == 'A' and len(IP4s) == 0:
474 if d.type == 'AAAA' and len(IP6s) == 0:
476 if str(d) not in dup_set:
480 # now expand the entries, if any are A record with ip set to $IP
481 # then replace with multiple entries, one for each interface IP
487 for i in range(len(IP4s)-1):
493 for i in range(len(IP6s)-1):
498 # now check if the entries already exist on the DNS server
500 if opts.all_names or not check_dns_name(d):
501 update_list.append(d)
503 if len(update_list) == 0:
505 print "No DNS updates needed"
512 # ask nsupdate to add entries as needed
513 for d in update_list:
515 if d.name.lower() == domain.lower():
517 if not d.type in [ 'A', 'AAAA' ]:
524 # delete the ccache if we created it
525 if ccachename is not None:
526 os.unlink(ccachename)
529 print("Failed update of %u entries" % error_count)
530 sys.exit(error_count)