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/>.
26 # ensure we get messages out immediately, so they get in the samba logs,
27 # and don't get swallowed by a timeout
28 os.putenv('PYTHONUNBUFFERED', '1')
30 # Find right directory when running from source tree
31 sys.path.insert(0, "bin/python")
35 from samba import getopt as options
36 from ldb import SCOPE_BASE
37 from samba.auth import system_session
38 from samba.samdb import SamDB
39 from samba.dcerpc import netlogon, winbind
41 samba.ensure_external_module("dns", "dnspython")
42 import dns.resolver as resolver
47 parser = optparse.OptionParser("samba_dnsupdate")
48 sambaopts = options.SambaOptions(parser)
49 parser.add_option_group(sambaopts)
50 parser.add_option_group(options.VersionOptions(parser))
51 parser.add_option("--verbose", action="store_true")
52 parser.add_option("--all-names", action="store_true")
53 parser.add_option("--all-interfaces", action="store_true")
54 parser.add_option("--use-file", type="string", help="Use a file, rather than real DNS calls")
55 parser.add_option("--update-list", type="string", help="Add DNS names from the given file")
60 opts, args = parser.parse_args()
66 lp = sambaopts.get_loadparm()
68 domain = lp.get("realm")
69 host = lp.get("netbios name")
70 if opts.all_interfaces:
73 all_interfaces = False
75 IPs = samba.interface_ips(lp, all_interfaces)
76 nsupdate_cmd = lp.get('nsupdate command')
79 print "No IP interfaces - skipping DNS updates"
85 ########################################################
86 # get credentials if we haven't got them already
87 def get_credentials(lp):
88 from samba import credentials
89 global ccachename, creds
92 creds = credentials.Credentials()
94 creds.set_machine_account(lp)
95 creds.set_krb_forwardable(credentials.NO_KRB_FORWARDABLE)
96 (tmp_fd, ccachename) = tempfile.mkstemp()
97 creds.get_named_ccache(lp, ccachename)
100 #############################################
101 # an object to hold a parsed DNS line
102 class dnsobj(object):
103 def __init__(self, string_form):
104 list = string_form.split()
108 self.existing_port = None
109 self.existing_weight = None
111 self.name = list[1].lower()
112 if self.type == 'SRV':
113 self.dest = list[2].lower()
115 elif self.type == 'A':
116 self.ip = list[2] # usually $IP, which gets replaced
117 elif self.type == 'CNAME':
118 self.dest = list[2].lower()
120 print "Received unexpected DNS reply of type %s" % self.type
124 if d.type == "A": return "%s %s %s" % (self.type, self.name, self.ip)
125 if d.type == "SRV": return "%s %s %s %s" % (self.type, self.name, self.dest, self.port)
126 if d.type == "CNAME": return "%s %s %s" % (self.type, self.name, self.dest)
129 ################################################
130 # parse a DNS line from
131 def parse_dns_line(line, sub_vars):
132 subline = samba.substitute_var(line, sub_vars)
136 ############################################
137 # see if two hostnames match
138 def hostname_match(h1, h2):
141 return h1.lower().rstrip('.') == h2.lower().rstrip('.')
144 ############################################
145 # check that a DNS entry exists
146 def check_dns_name(d):
147 normalised_name = d.name.rstrip('.') + '.'
149 print "Looking for DNS entry %s as %s" % (d, normalised_name)
151 if opts.use_file is not None:
153 dns_file = open(opts.use_file, "r")
157 for line in dns_file:
159 if line == '' or line[0] == "#":
161 if line.lower() == str(d).lower():
166 ans = resolver.query(normalised_name, d.type)
167 except resolver.NXDOMAIN:
170 # we need to be sure that our IP is there
172 if str(rdata) == str(d.ip):
174 if d.type == 'CNAME':
175 for i in range(len(ans)):
176 if hostname_match(ans[i].target, d.dest):
181 print "Checking %s against %s" % (rdata, d)
182 if hostname_match(rdata.target, d.dest):
183 if str(rdata.port) == str(d.port):
186 d.existing_port = str(rdata.port)
187 d.existing_weight = str(rdata.weight)
189 print "Failed to find DNS entry %s" % d
194 ###########################################
195 # get the list of substitution vars
196 def get_subst_vars():
200 samdb = SamDB(url=lp.get("sam database"), session_info=system_session(),
203 vars['DNSDOMAIN'] = lp.get('realm').lower()
204 vars['DNSFOREST'] = lp.get('realm').lower()
205 vars['HOSTNAME'] = lp.get('netbios name').lower() + "." + vars['DNSDOMAIN']
206 vars['NTDSGUID'] = samdb.get_ntds_GUID()
207 vars['SITE'] = samdb.server_site_name()
208 res = samdb.search(base=None, scope=SCOPE_BASE, attrs=["objectGUID"])
209 guid = samdb.schema_format_value("objectGUID", res[0]['objectGUID'][0])
210 vars['DOMAINGUID'] = guid
211 am_rodc = samdb.am_rodc()
216 ############################################
217 # call nsupdate for an entry
218 def call_nsupdate(d):
219 global ccachename, nsupdate_cmd
222 print "Calling nsupdate for %s" % d
224 if opts.use_file is not None:
225 wfile = open(opts.use_file, 'a')
226 fcntl.lockf(wfile, fcntl.LOCK_EX)
227 wfile.write(str(d)+"\n")
228 fcntl.lockf(wfile, fcntl.LOCK_UN)
231 normalised_name = d.name.rstrip('.') + '.'
233 (tmp_fd, tmpfile) = tempfile.mkstemp()
234 f = os.fdopen(tmp_fd, 'w')
236 f.write("update add %s %u A %s\n" % (normalised_name, default_ttl, d.ip))
238 if d.existing_port is not None:
239 f.write("update delete %s SRV 0 %s %s %s\n" % (normalised_name, d.existing_weight,
240 d.existing_port, d.dest))
241 f.write("update add %s %u SRV 0 100 %s %s\n" % (normalised_name, default_ttl, d.port, d.dest))
242 if d.type == "CNAME":
243 f.write("update add %s %u CNAME %s\n" % (normalised_name, default_ttl, d.dest))
249 os.putenv("KRB5CCNAME", ccachename)
250 os.system("%s %s" % (nsupdate_cmd, tmpfile))
255 def rodc_dns_update(d, t):
256 '''a single DNS update via the RODC netlogon call'''
260 print "Calling netlogon RODC update for %s" % d
263 netlogon.NlDnsLdapAtSite : netlogon.NlDnsInfoTypeNone,
264 netlogon.NlDnsGcAtSite : netlogon.NlDnsDomainNameAlias,
265 netlogon.NlDnsDsaCname : netlogon.NlDnsDomainNameAlias,
266 netlogon.NlDnsKdcAtSite : netlogon.NlDnsInfoTypeNone,
267 netlogon.NlDnsDcAtSite : netlogon.NlDnsInfoTypeNone,
268 netlogon.NlDnsRfc1510KdcAtSite : netlogon.NlDnsInfoTypeNone,
269 netlogon.NlDnsGenericGcAtSite : netlogon.NlDnsDomainNameAlias
272 w = winbind.winbind("irpc:winbind_server", lp)
273 dns_names = netlogon.NL_DNS_NAME_INFO_ARRAY()
275 name = netlogon.NL_DNS_NAME_INFO()
277 name.dns_domain_info_type = typemap[t]
280 if d.port is not None:
281 name.port = int(d.port)
282 name.dns_register = True
283 dns_names.names = [ name ]
284 site_name = sub_vars['SITE'].decode('utf-8')
287 ret_names = w.DsrUpdateReadOnlyServerDnsRecords(site_name, default_ttl, dns_names)
288 if ret_names.names[0].status != 0:
289 print("Failed to set DNS entry: %s (status %u)" % (d, ret_names.names[0].status))
290 except RuntimeError, reason:
291 print("Error setting DNS entry of type %u: %s: %s" % (t, d, reason))
294 def call_rodc_update(d):
295 '''RODCs need to use the netlogon API for nsupdate'''
298 # we expect failure for 3268 if we aren't a GC
299 if d.port is not None and int(d.port) == 3268:
302 # map the DNS request to a netlogon update type
304 netlogon.NlDnsLdapAtSite : '_ldap._tcp.${SITE}._sites.${DNSDOMAIN}',
305 netlogon.NlDnsGcAtSite : '_ldap._tcp.${SITE}._sites.gc._msdcs.${DNSDOMAIN}',
306 netlogon.NlDnsDsaCname : '${NTDSGUID}._msdcs.${DNSFOREST}',
307 netlogon.NlDnsKdcAtSite : '_kerberos._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
308 netlogon.NlDnsDcAtSite : '_ldap._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
309 netlogon.NlDnsRfc1510KdcAtSite : '_kerberos._tcp.${SITE}._sites.${DNSDOMAIN}',
310 netlogon.NlDnsGenericGcAtSite : '_gc._tcp.${SITE}._sites.${DNSFOREST}'
314 subname = samba.substitute_var(map[t], sub_vars)
315 if subname.lower() == d.name.lower():
316 # found a match - do the update
317 rodc_dns_update(d, t)
320 print("Unable to map to netlogon DNS update: %s" % d)
323 # get the list of DNS entries we should have
325 dns_update_list = opts.update_list
327 dns_update_list = lp.private_path('dns_update_list')
329 # use our private krb5.conf to avoid problems with the wrong domain
330 # bind9 nsupdate wants the default domain set
331 krb5conf = lp.private_path('krb5.conf')
332 os.putenv('KRB5_CONFIG', krb5conf)
334 file = open(dns_update_list, "r")
336 # get the substitution dictionary
337 sub_vars = get_subst_vars()
339 # build up a list of update commands to pass to nsupdate
343 # read each line, and check that the DNS name exists
346 if line == '' or line[0] == "#":
348 d = parse_dns_line(line, sub_vars)
351 # now expand the entries, if any are A record with ip set to $IP
352 # then replace with multiple entries, one for each interface IP
354 if d.type == 'A' and d.ip == "$IP":
356 for i in range(len(IPs)-1):
361 # now check if the entries already exist on the DNS server
363 if opts.all_names or not check_dns_name(d):
364 update_list.append(d)
366 if len(update_list) == 0:
368 print "No DNS updates needed"
374 # ask nsupdate to add entries as needed
375 for d in update_list:
381 # delete the ccache if we created it
382 if ccachename is not None:
383 os.unlink(ccachename)