source: trunk/server/source4/scripting/bin/samba_dnsupdate

Last change on this file was 745, checked in by Silvan Scherrer, 13 years ago

Samba Server: updated trunk to 3.6.0
File size: 13.6 KB
Line 
1#!/usr/bin/env python
2#
3# update our DNS names using TSIG-GSS
4#
5# Copyright (C) Andrew Tridgell 2010
6#
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.
11#
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.
16#
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/>.
19
20
21import os
22import fcntl
23import sys
24import tempfile
25import subprocess
26
27# ensure we get messages out immediately, so they get in the samba logs,
28# and don't get swallowed by a timeout
29os.environ['PYTHONUNBUFFERED'] = '1'
30
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
34# the US)
35os.environ["TZ"] = "GMT"
36
37# Find right directory when running from source tree
38sys.path.insert(0, "bin/python")
39
40import samba
41import optparse
42from samba import getopt as options
43from ldb import SCOPE_BASE
44from samba.auth import system_session
45from samba.samdb import SamDB
46from samba.dcerpc import netlogon, winbind
47
48samba.ensure_external_module("dns", "dnspython")
49import dns.resolver
50import dns.exception
51
52default_ttl = 900
53am_rodc = False
54error_count = 0
55
56parser = optparse.OptionParser("samba_dnsupdate")
57sambaopts = options.SambaOptions(parser)
58parser.add_option_group(sambaopts)
59parser.add_option_group(options.VersionOptions(parser))
60parser.add_option("--verbose", action="store_true")
61parser.add_option("--all-names", action="store_true")
62parser.add_option("--all-interfaces", action="store_true")
63parser.add_option("--use-file", type="string", help="Use a file, rather than real DNS calls")
64parser.add_option("--update-list", type="string", help="Add DNS names from the given file")
65parser.add_option("--fail-immediately", action='store_true', help="Exit on first failure")
66
67creds = None
68ccachename = None
69
70opts, args = parser.parse_args()
71
72if len(args) != 0:
73 parser.print_usage()
74 sys.exit(1)
75
76lp = sambaopts.get_loadparm()
77
78domain = lp.get("realm")
79host = lp.get("netbios name")
80if opts.all_interfaces:
81 all_interfaces = True
82else:
83 all_interfaces = False
84
85IPs = samba.interface_ips(lp, all_interfaces)
86nsupdate_cmd = lp.get('nsupdate command')
87
88if len(IPs) == 0:
89 print "No IP interfaces - skipping DNS updates"
90 sys.exit(0)
91
92if opts.verbose:
93 print "IPs: %s" % IPs
94
95########################################################
96# get credentials if we haven't got them already
97def get_credentials(lp):
98 from samba import credentials
99 global ccachename, creds
100 if creds is not None:
101 return
102 creds = credentials.Credentials()
103 creds.guess(lp)
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)
108
109
110#############################################
111# an object to hold a parsed DNS line
112class dnsobj(object):
113 def __init__(self, string_form):
114 list = string_form.split()
115 self.dest = None
116 self.port = None
117 self.ip = None
118 self.existing_port = None
119 self.existing_weight = None
120 self.type = list[0]
121 self.name = list[1].lower()
122 if self.type == 'SRV':
123 self.dest = list[2].lower()
124 self.port = list[3]
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()
129 else:
130 print "Received unexpected DNS reply of type %s" % self.type
131 raise
132
133 def __str__(self):
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)
137
138
139################################################
140# parse a DNS line from
141def parse_dns_line(line, sub_vars):
142 subline = samba.substitute_var(line, sub_vars)
143 d = dnsobj(subline)
144 return d
145
146############################################
147# see if two hostnames match
148def hostname_match(h1, h2):
149 h1 = str(h1)
150 h2 = str(h2)
151 return h1.lower().rstrip('.') == h2.lower().rstrip('.')
152
153
154############################################
155# check that a DNS entry exists
156def check_dns_name(d):
157 normalised_name = d.name.rstrip('.') + '.'
158 if opts.verbose:
159 print "Looking for DNS entry %s as %s" % (d, normalised_name)
160
161 if opts.use_file is not None:
162 try:
163 dns_file = open(opts.use_file, "r")
164 except IOError:
165 return False
166
167 for line in dns_file:
168 line = line.strip()
169 if line == '' or line[0] == "#":
170 continue
171 if line.lower() == str(d).lower():
172 return True
173 return False
174
175 try:
176 ans = dns.resolver.query(normalised_name, d.type)
177 except dns.exception.DNSException:
178 if opts.verbose:
179 print "Failed to find DNS entry %s" % d
180 return False
181 if d.type == 'A':
182 # we need to be sure that our IP is there
183 for rdata in ans:
184 if str(rdata) == str(d.ip):
185 return True
186 if d.type == 'CNAME':
187 for i in range(len(ans)):
188 if hostname_match(ans[i].target, d.dest):
189 return True
190 if d.type == 'SRV':
191 for rdata in ans:
192 if opts.verbose:
193 print "Checking %s against %s" % (rdata, d)
194 if hostname_match(rdata.target, d.dest):
195 if str(rdata.port) == str(d.port):
196 return True
197 else:
198 d.existing_port = str(rdata.port)
199 d.existing_weight = str(rdata.weight)
200
201 if opts.verbose:
202 print "Failed to find matching DNS entry %s" % d
203
204 return False
205
206
207###########################################
208# get the list of substitution vars
209def get_subst_vars():
210 global lp, am_rodc
211 vars = {}
212
213 samdb = SamDB(url=lp.get("sam database"), session_info=system_session(),
214 lp=lp)
215
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()
225
226 return vars
227
228
229############################################
230# call nsupdate for an entry
231def call_nsupdate(d):
232 global ccachename, nsupdate_cmd
233
234 if opts.verbose:
235 print "Calling nsupdate for %s" % d
236
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)
242 return
243
244 normalised_name = d.name.rstrip('.') + '.'
245
246 (tmp_fd, tmpfile) = tempfile.mkstemp()
247 f = os.fdopen(tmp_fd, 'w')
248 if d.type == "A":
249 f.write("update add %s %u A %s\n" % (normalised_name, default_ttl, d.ip))
250 if d.type == "SRV":
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))
257 if opts.verbose:
258 f.write("show\n")
259 f.write("send\n")
260 f.close()
261
262 os.environ["KRB5CCNAME"] = ccachename
263 try:
264 cmd = nsupdate_cmd[:]
265 cmd.append(tmpfile)
266 subprocess.check_call(cmd, shell=False)
267 except Exception, estr:
268 global error_count
269 if opts.fail_immediately:
270 sys.exit(1)
271 error_count = error_count + 1
272 if opts.verbose:
273 print("Failed nsupdate: %s : %s" % (str(d), estr))
274 os.unlink(tmpfile)
275
276
277
278def rodc_dns_update(d, t):
279 '''a single DNS update via the RODC netlogon call'''
280 global sub_vars
281
282 if opts.verbose:
283 print "Calling netlogon RODC update for %s" % d
284
285 typemap = {
286 netlogon.NlDnsLdapAtSite : netlogon.NlDnsInfoTypeNone,
287 netlogon.NlDnsGcAtSite : netlogon.NlDnsDomainNameAlias,
288 netlogon.NlDnsDsaCname : netlogon.NlDnsDomainNameAlias,
289 netlogon.NlDnsKdcAtSite : netlogon.NlDnsInfoTypeNone,
290 netlogon.NlDnsDcAtSite : netlogon.NlDnsInfoTypeNone,
291 netlogon.NlDnsRfc1510KdcAtSite : netlogon.NlDnsInfoTypeNone,
292 netlogon.NlDnsGenericGcAtSite : netlogon.NlDnsDomainNameAlias
293 }
294
295 w = winbind.winbind("irpc:winbind_server", lp)
296 dns_names = netlogon.NL_DNS_NAME_INFO_ARRAY()
297 dns_names.count = 1
298 name = netlogon.NL_DNS_NAME_INFO()
299 name.type = t
300 name.dns_domain_info_type = typemap[t]
301 name.priority = 0
302 name.weight = 0
303 if d.port is not None:
304 name.port = int(d.port)
305 name.dns_register = True
306 dns_names.names = [ name ]
307 site_name = sub_vars['SITE'].decode('utf-8')
308
309 global error_count
310
311 try:
312 ret_names = w.DsrUpdateReadOnlyServerDnsRecords(site_name, default_ttl, dns_names)
313 if ret_names.names[0].status != 0:
314 print("Failed to set DNS entry: %s (status %u)" % (d, ret_names.names[0].status))
315 error_count = error_count + 1
316 except RuntimeError, reason:
317 print("Error setting DNS entry of type %u: %s: %s" % (t, d, reason))
318 error_count = error_count + 1
319
320 if error_count != 0 and opts.fail_immediately:
321 sys.exit(1)
322
323
324def call_rodc_update(d):
325 '''RODCs need to use the netlogon API for nsupdate'''
326 global lp, sub_vars
327
328 # we expect failure for 3268 if we aren't a GC
329 if d.port is not None and int(d.port) == 3268:
330 return
331
332 # map the DNS request to a netlogon update type
333 map = {
334 netlogon.NlDnsLdapAtSite : '_ldap._tcp.${SITE}._sites.${DNSDOMAIN}',
335 netlogon.NlDnsGcAtSite : '_ldap._tcp.${SITE}._sites.gc._msdcs.${DNSDOMAIN}',
336 netlogon.NlDnsDsaCname : '${NTDSGUID}._msdcs.${DNSFOREST}',
337 netlogon.NlDnsKdcAtSite : '_kerberos._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
338 netlogon.NlDnsDcAtSite : '_ldap._tcp.${SITE}._sites.dc._msdcs.${DNSDOMAIN}',
339 netlogon.NlDnsRfc1510KdcAtSite : '_kerberos._tcp.${SITE}._sites.${DNSDOMAIN}',
340 netlogon.NlDnsGenericGcAtSite : '_gc._tcp.${SITE}._sites.${DNSFOREST}'
341 }
342
343 for t in map:
344 subname = samba.substitute_var(map[t], sub_vars)
345 if subname.lower() == d.name.lower():
346 # found a match - do the update
347 rodc_dns_update(d, t)
348 return
349 if opts.verbose:
350 print("Unable to map to netlogon DNS update: %s" % d)
351
352
353# get the list of DNS entries we should have
354if opts.update_list:
355 dns_update_list = opts.update_list
356else:
357 dns_update_list = lp.private_path('dns_update_list')
358
359# use our private krb5.conf to avoid problems with the wrong domain
360# bind9 nsupdate wants the default domain set
361krb5conf = lp.private_path('krb5.conf')
362os.environ['KRB5_CONFIG'] = krb5conf
363
364file = open(dns_update_list, "r")
365
366# get the substitution dictionary
367sub_vars = get_subst_vars()
368
369# build up a list of update commands to pass to nsupdate
370update_list = []
371dns_list = []
372
373# read each line, and check that the DNS name exists
374for line in file:
375 line = line.strip()
376 if line == '' or line[0] == "#":
377 continue
378 d = parse_dns_line(line, sub_vars)
379 dns_list.append(d)
380
381# now expand the entries, if any are A record with ip set to $IP
382# then replace with multiple entries, one for each interface IP
383for d in dns_list:
384 if d.type == 'A' and d.ip == "$IP":
385 d.ip = IPs[0]
386 for i in range(len(IPs)-1):
387 d2 = dnsobj(str(d))
388 d2.ip = IPs[i+1]
389 dns_list.append(d2)
390
391# now check if the entries already exist on the DNS server
392for d in dns_list:
393 if opts.all_names or not check_dns_name(d):
394 update_list.append(d)
395
396if len(update_list) == 0:
397 if opts.verbose:
398 print "No DNS updates needed"
399 sys.exit(0)
400
401# get our krb5 creds
402get_credentials(lp)
403
404# ask nsupdate to add entries as needed
405for d in update_list:
406 if am_rodc:
407 if d.name.lower() == domain.lower():
408 continue
409 if d.type != 'A':
410 call_rodc_update(d)
411 else:
412 call_nsupdate(d)
413 else:
414 call_nsupdate(d)
415
416# delete the ccache if we created it
417if ccachename is not None:
418 os.unlink(ccachename)
419
420if error_count != 0:
421 print("Failed update of %u entries" % error_count)
422sys.exit(error_count)
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