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")
56 parser = optparse.OptionParser("samba_dnsupdate")
57 sambaopts = options.SambaOptions(parser)
58 parser.add_option_group(sambaopts)
59 parser.add_option_group(options.VersionOptions(parser))
60 parser.add_option("--verbose", action="store_true")
61 parser.add_option("--all-names", action="store_true")
62 parser.add_option("--all-interfaces", action="store_true")
63 parser.add_option("--use-file", type="string", help="Use a file, rather than real DNS calls")
64 parser.add_option("--update-list", type="string", help="Add DNS names from the given file")
65 parser.add_option("--fail-immediately", action='store_true', help="Exit on first failure")
70 opts, args = parser.parse_args()
76 lp = sambaopts.get_loadparm()
78 domain = lp.get("realm")
79 host = lp.get("netbios name")
80 if opts.all_interfaces:
83 all_interfaces = False
85 IPs = samba.interface_ips(lp, all_interfaces)
86 nsupdate_cmd = lp.get('nsupdate command')
89 print "No IP interfaces - skipping DNS updates"
95 ########################################################
96 # get credentials if we haven't got them already
97 def get_credentials(lp):
98 from samba import credentials
99 global ccachename, creds
100 if creds is not None:
102 creds = credentials.Credentials()
104 creds.set_machine_account(lp)
105 creds.set_krb_forwardable(credentials.NO_KRB_FORWARDABLE)
106 (tmp_fd, ccachename) = tempfile.mkstemp()
107 creds.get_named_ccache(lp, ccachename)
110 #############################################
111 # an object to hold a parsed DNS line
112 class dnsobj(object):
113 def __init__(self, string_form):
114 list = string_form.split()
118 self.existing_port = None
119 self.existing_weight = None
121 self.name = list[1].lower()
122 if self.type == 'SRV':
123 self.dest = list[2].lower()
125 elif self.type == 'A':
126 self.ip = list[2] # usually $IP, which gets replaced
127 elif self.type == 'CNAME':
128 self.dest = list[2].lower()
130 print "Received unexpected DNS reply of type %s" % self.type
134 if d.type == "A": return "%s %s %s" % (self.type, self.name, self.ip)
135 if d.type == "SRV": return "%s %s %s %s" % (self.type, self.name, self.dest, self.port)
136 if d.type == "CNAME": return "%s %s %s" % (self.type, self.name, self.dest)
139 ################################################
140 # parse a DNS line from
141 def parse_dns_line(line, sub_vars):
142 subline = samba.substitute_var(line, sub_vars)
146 ############################################
147 # see if two hostnames match
148 def hostname_match(h1, h2):
151 return h1.lower().rstrip('.') == h2.lower().rstrip('.')
154 ############################################
155 # check that a DNS entry exists
156 def check_dns_name(d):
157 normalised_name = d.name.rstrip('.') + '.'
159 print "Looking for DNS entry %s as %s" % (d, normalised_name)
161 if opts.use_file is not None:
163 dns_file = open(opts.use_file, "r")
167 for line in dns_file:
169 if line == '' or line[0] == "#":
171 if line.lower() == str(d).lower():
176 ans = dns.resolver.query(normalised_name, d.type)
177 except dns.exception.DNSException:
179 print "Failed to find DNS entry %s" % d
182 # we need to be sure that our IP is there
184 if str(rdata) == str(d.ip):
186 if d.type == 'CNAME':
187 for i in range(len(ans)):
188 if hostname_match(ans[i].target, d.dest):
193 print "Checking %s against %s" % (rdata, d)
194 if hostname_match(rdata.target, d.dest):
195 if str(rdata.port) == str(d.port):
198 d.existing_port = str(rdata.port)
199 d.existing_weight = str(rdata.weight)
202 print "Failed to find matching DNS entry %s" % d
207 ###########################################
208 # get the list of substitution vars
209 def get_subst_vars():
213 samdb = SamDB(url=lp.get("sam database"), session_info=system_session(),
216 vars['DNSDOMAIN'] = lp.get('realm').lower()
217 vars['DNSFOREST'] = lp.get('realm').lower()
218 vars['HOSTNAME'] = lp.get('netbios name').lower() + "." + vars['DNSDOMAIN']
219 vars['NTDSGUID'] = samdb.get_ntds_GUID()
220 vars['SITE'] = samdb.server_site_name()
221 res = samdb.search(base=None, scope=SCOPE_BASE, attrs=["objectGUID"])
222 guid = samdb.schema_format_value("objectGUID", res[0]['objectGUID'][0])
223 vars['DOMAINGUID'] = guid
224 am_rodc = samdb.am_rodc()
229 ############################################
230 # call nsupdate for an entry
231 def call_nsupdate(d):
232 global ccachename, nsupdate_cmd
235 print "Calling nsupdate for %s" % d
237 if opts.use_file is not None:
238 wfile = open(opts.use_file, 'a')
239 fcntl.lockf(wfile, fcntl.LOCK_EX)
240 wfile.write(str(d)+"\n")
241 fcntl.lockf(wfile, fcntl.LOCK_UN)
244 normalised_name = d.name.rstrip('.') + '.'
246 (tmp_fd, tmpfile) = tempfile.mkstemp()
247 f = os.fdopen(tmp_fd, 'w')
249 f.write("update add %s %u A %s\n" % (normalised_name, default_ttl, d.ip))
251 if d.existing_port is not None:
252 f.write("update delete %s SRV 0 %s %s %s\n" % (normalised_name, d.existing_weight,
253 d.existing_port, d.dest))
254 f.write("update add %s %u SRV 0 100 %s %s\n" % (normalised_name, default_ttl, d.port, d.dest))
255 if d.type == "CNAME":
256 f.write("update add %s %u CNAME %s\n" % (normalised_name, default_ttl, d.dest))
262 os.putenv("KRB5CCNAME", ccachename)
264 cmd = "%s %s" % (nsupdate_cmd, tmpfile)
265 subprocess.check_call(cmd, shell=True)
266 except Exception, estr:
268 if opts.fail_immediately:
270 error_count = error_count + 1
272 print("Failed nsupdate: %s : %s" % (str(d), estr))
277 def rodc_dns_update(d, t):
278 '''a single DNS update via the RODC netlogon call'''
282 print "Calling netlogon RODC update for %s" % d
285 netlogon.NlDnsLdapAtSite : netlogon.NlDnsInfoTypeNone,
286 netlogon.NlDnsGcAtSite : netlogon.NlDnsDomainNameAlias,
287 netlogon.NlDnsDsaCname : netlogon.NlDnsDomainNameAlias,
288 netlogon.NlDnsKdcAtSite : netlogon.NlDnsInfoTypeNone,
289 netlogon.NlDnsDcAtSite : netlogon.NlDnsInfoTypeNone,
290 netlogon.NlDnsRfc1510KdcAtSite : netlogon.NlDnsInfoTypeNone,
291 netlogon.NlDnsGenericGcAtSite : netlogon.NlDnsDomainNameAlias
294 w = winbind.winbind("irpc:winbind_server", lp)
295 dns_names = netlogon.NL_DNS_NAME_INFO_ARRAY()
297 name = netlogon.NL_DNS_NAME_INFO()
299 name.dns_domain_info_type = typemap[t]
302 if d.port is not None:
303 name.port = int(d.port)
304 name.dns_register = True
305 dns_names.names = [ name ]
306 site_name = sub_vars['SITE'].decode('utf-8')
311 ret_names = w.DsrUpdateReadOnlyServerDnsRecords(site_name, default_ttl, dns_names)
312 if ret_names.names[0].status != 0:
313 print("Failed to set DNS entry: %s (status %u)" % (d, ret_names.names[0].status))
314 error_count = error_count + 1
315 except RuntimeError, reason:
316 print("Error setting DNS entry of type %u: %s: %s" % (t, d, reason))
317 error_count = error_count + 1
319 if error_count != 0 and opts.fail_immediately:
323 def call_rodc_update(d):
324 '''RODCs need to use the netlogon API for nsupdate'''
327 # we expect failure for 3268 if we aren't a GC
328 if d.port is not None and int(d.port) == 3268:
331 # map the DNS request to a netlogon update type
333 netlogon.NlDnsLdapAtSite : '_ldap._tcp.${SITE}._sites.${DNSDOMAIN}',
334 netlogon.NlDnsGcAtSite : '_ldap._tcp.${SITE}._sites.gc._msdcs.${DNSDOMAIN}',
335 netlogon.NlDnsDsaCname : '${NTDSGUID}._msdcs.${DNSFOREST}',
336 netlogon.NlDnsKdcAtSite : '_kerberos._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
337 netlogon.NlDnsDcAtSite : '_ldap._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
338 netlogon.NlDnsRfc1510KdcAtSite : '_kerberos._tcp.${SITE}._sites.${DNSDOMAIN}',
339 netlogon.NlDnsGenericGcAtSite : '_gc._tcp.${SITE}._sites.${DNSFOREST}'
343 subname = samba.substitute_var(map[t], sub_vars)
344 if subname.lower() == d.name.lower():
345 # found a match - do the update
346 rodc_dns_update(d, t)
349 print("Unable to map to netlogon DNS update: %s" % d)
352 # get the list of DNS entries we should have
354 dns_update_list = opts.update_list
356 dns_update_list = lp.private_path('dns_update_list')
358 # use our private krb5.conf to avoid problems with the wrong domain
359 # bind9 nsupdate wants the default domain set
360 krb5conf = lp.private_path('krb5.conf')
361 os.putenv('KRB5_CONFIG', krb5conf)
363 file = open(dns_update_list, "r")
365 # get the substitution dictionary
366 sub_vars = get_subst_vars()
368 # build up a list of update commands to pass to nsupdate
372 # read each line, and check that the DNS name exists
375 if line == '' or line[0] == "#":
377 d = parse_dns_line(line, sub_vars)
380 # now expand the entries, if any are A record with ip set to $IP
381 # then replace with multiple entries, one for each interface IP
383 if d.type == 'A' and d.ip == "$IP":
385 for i in range(len(IPs)-1):
390 # now check if the entries already exist on the DNS server
392 if opts.all_names or not check_dns_name(d):
393 update_list.append(d)
395 if len(update_list) == 0:
397 print "No DNS updates needed"
403 # ask nsupdate to add entries as needed
404 for d in update_list:
406 if d.name.lower() == domain.lower():
415 # delete the ccache if we created it
416 if ccachename is not None:
417 os.unlink(ccachename)
420 print("Failed update of %u entries" % error_count)
421 sys.exit(error_count)