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0fbd7c3c MT |
1 | #!/usr/bin/python |
2 | ############################################################################### | |
3 | # # | |
4 | # IPFire.org - A linux based firewall # | |
5 | # Copyright (C) 2016 Michael Tremer # | |
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 | ############################################################################### | |
21 | ||
22 | import argparse | |
23 | import datetime | |
24 | import daemon | |
74a5ab67 | 25 | import ipaddress |
0fbd7c3c MT |
26 | import logging |
27 | import logging.handlers | |
b666975e | 28 | import os |
0fbd7c3c MT |
29 | import re |
30 | import signal | |
31 | import subprocess | |
b666975e | 32 | import tempfile |
0fbd7c3c MT |
33 | |
34 | import inotify.adapters | |
35 | ||
077ea717 MT |
36 | LOCAL_TTL = 60 |
37 | ||
0fbd7c3c MT |
38 | def setup_logging(loglevel=logging.INFO): |
39 | log = logging.getLogger("dhcp") | |
40 | log.setLevel(loglevel) | |
41 | ||
42 | handler = logging.handlers.SysLogHandler(address="/dev/log", facility="daemon") | |
43 | handler.setLevel(loglevel) | |
44 | ||
45 | formatter = logging.Formatter("%(name)s[%(process)d]: %(message)s") | |
46 | handler.setFormatter(formatter) | |
47 | ||
48 | log.addHandler(handler) | |
49 | ||
50 | return log | |
51 | ||
52 | log = logging.getLogger("dhcp") | |
53 | ||
e22bcd38 MT |
54 | def ip_address_to_reverse_pointer(address): |
55 | parts = address.split(".") | |
56 | parts.reverse() | |
57 | ||
58 | return "%s.in-addr.arpa" % ".".join(parts) | |
59 | ||
60 | def reverse_pointer_to_ip_address(rr): | |
61 | parts = rr.split(".") | |
62 | ||
63 | # Only take IP address part | |
64 | parts = reversed(parts[0:4]) | |
65 | ||
66 | return ".".join(parts) | |
67 | ||
0fbd7c3c | 68 | class UnboundDHCPLeasesBridge(object): |
7354d294 | 69 | def __init__(self, dhcp_leases_file, fix_leases_file, unbound_leases_file, hosts_file): |
0fbd7c3c | 70 | self.leases_file = dhcp_leases_file |
86c9deb2 | 71 | self.fix_leases_file = fix_leases_file |
7354d294 | 72 | self.hosts_file = hosts_file |
0fbd7c3c MT |
73 | |
74 | self.unbound = UnboundConfigWriter(unbound_leases_file) | |
75 | self.running = False | |
76 | ||
77 | def run(self): | |
78 | log.info("Unbound DHCP Leases Bridge started on %s" % self.leases_file) | |
79 | self.running = True | |
80 | ||
7354d294 MT |
81 | # Initial setup |
82 | self.hosts = self.read_static_hosts() | |
0fbd7c3c MT |
83 | self.update_dhcp_leases() |
84 | ||
7354d294 MT |
85 | i = inotify.adapters.Inotify([ |
86 | self.leases_file, | |
87 | self.fix_leases_file, | |
88 | self.hosts_file, | |
89 | ]) | |
0fbd7c3c MT |
90 | |
91 | for event in i.event_gen(): | |
92 | # End if we are requested to terminate | |
93 | if not self.running: | |
94 | break | |
95 | ||
96 | if event is None: | |
97 | continue | |
98 | ||
99 | header, type_names, watch_path, filename = event | |
100 | ||
101 | # Update leases after leases file has been modified | |
102 | if "IN_MODIFY" in type_names: | |
7354d294 MT |
103 | # Reload hosts |
104 | if watch_path == self.hosts_file: | |
105 | self.hosts = self.read_static_hosts() | |
106 | ||
0fbd7c3c MT |
107 | self.update_dhcp_leases() |
108 | ||
86c9deb2 MT |
109 | # If the file is deleted, we re-add the watcher |
110 | if "IN_IGNORED" in type_names: | |
111 | i.add_watch(watch_path) | |
112 | ||
0fbd7c3c MT |
113 | log.info("Unbound DHCP Leases Bridge terminated") |
114 | ||
115 | def update_dhcp_leases(self): | |
86c9deb2 MT |
116 | leases = [] |
117 | ||
118 | for lease in DHCPLeases(self.leases_file): | |
5d4f3a42 MT |
119 | # Don't bother with any leases that don't have a hostname |
120 | if not lease.fqdn: | |
121 | continue | |
122 | ||
86c9deb2 MT |
123 | leases.append(lease) |
124 | ||
125 | for lease in FixLeases(self.fix_leases_file): | |
126 | leases.append(lease) | |
0fbd7c3c | 127 | |
c7b83f9b MT |
128 | # Skip any leases that also are a static host |
129 | leases = [l for l in leases if not l.fqdn in self.hosts] | |
130 | ||
131 | # Remove any inactive or expired leases | |
132 | leases = [l for l in leases if l.active and not l.expired] | |
133 | ||
134 | # Dump leases | |
135 | if leases: | |
136 | log.debug("DHCP Leases:") | |
137 | for lease in leases: | |
138 | log.debug(" %s:" % lease.fqdn) | |
139 | log.debug(" State: %s" % lease.binding_state) | |
140 | log.debug(" Start: %s" % lease.time_starts) | |
141 | log.debug(" End : %s" % lease.time_ends) | |
142 | if lease.expired: | |
143 | log.debug(" Expired") | |
144 | ||
0fbd7c3c MT |
145 | self.unbound.update_dhcp_leases(leases) |
146 | ||
7354d294 MT |
147 | def read_static_hosts(self): |
148 | log.info("Reading static hosts from %s" % self.hosts_file) | |
149 | ||
150 | hosts = {} | |
151 | with open(self.hosts_file) as f: | |
152 | for line in f.readlines(): | |
153 | line = line.rstrip() | |
154 | ||
155 | try: | |
156 | enabled, ipaddr, hostname, domainname = line.split(",") | |
157 | except: | |
158 | log.warning("Could not parse line: %s" % line) | |
159 | continue | |
160 | ||
161 | # Skip any disabled entries | |
162 | if not enabled == "on": | |
163 | continue | |
164 | ||
165 | if hostname and domainname: | |
166 | fqdn = "%s.%s" % (hostname, domainname) | |
167 | elif hostname: | |
168 | fqdn = hostname | |
169 | elif domainname: | |
170 | fqdn = domainname | |
171 | ||
172 | try: | |
173 | hosts[fqdn].append(ipaddr) | |
174 | hosts[fqdn].sort() | |
175 | except KeyError: | |
176 | hosts[fqdn] = [ipaddr,] | |
177 | ||
178 | # Dump everything in the logs | |
179 | log.debug("Static hosts:") | |
180 | for hostname, addresses in hosts.items(): | |
181 | log.debug(" %-20s : %s" % (hostname, ", ".join(addresses))) | |
182 | ||
183 | return hosts | |
184 | ||
0fbd7c3c MT |
185 | def terminate(self): |
186 | self.running = False | |
187 | ||
188 | ||
189 | class DHCPLeases(object): | |
190 | regex_leaseblock = re.compile(r"lease (?P<ipaddr>\d+\.\d+\.\d+\.\d+) {(?P<config>[\s\S]+?)\n}") | |
191 | ||
192 | def __init__(self, path): | |
193 | self.path = path | |
194 | ||
195 | self._leases = self._parse() | |
196 | ||
197 | def __iter__(self): | |
198 | return iter(self._leases) | |
199 | ||
200 | def _parse(self): | |
86c9deb2 MT |
201 | log.info("Reading DHCP leases from %s" % self.path) |
202 | ||
0fbd7c3c MT |
203 | leases = [] |
204 | ||
205 | with open(self.path) as f: | |
206 | # Read entire leases file | |
207 | data = f.read() | |
208 | ||
209 | for match in self.regex_leaseblock.finditer(data): | |
210 | block = match.groupdict() | |
211 | ||
212 | ipaddr = block.get("ipaddr") | |
213 | config = block.get("config") | |
214 | ||
215 | properties = self._parse_block(config) | |
216 | ||
217 | # Skip any abandoned leases | |
218 | if not "hardware" in properties: | |
219 | continue | |
220 | ||
221 | lease = Lease(ipaddr, properties) | |
222 | ||
223 | # Check if a lease for this Ethernet address already | |
224 | # exists in the list of known leases. If so replace | |
225 | # if with the most recent lease | |
226 | for i, l in enumerate(leases): | |
8b1eb795 | 227 | if l.ipaddr == lease.ipaddr: |
0fbd7c3c MT |
228 | leases[i] = max(lease, l) |
229 | break | |
230 | ||
231 | else: | |
232 | leases.append(lease) | |
233 | ||
234 | return leases | |
235 | ||
236 | def _parse_block(self, block): | |
237 | properties = {} | |
238 | ||
239 | for line in block.splitlines(): | |
240 | if not line: | |
241 | continue | |
242 | ||
243 | # Remove trailing ; from line | |
244 | if line.endswith(";"): | |
245 | line = line[:-1] | |
246 | ||
247 | # Invalid line if it doesn't end with ; | |
248 | else: | |
249 | continue | |
250 | ||
251 | # Remove any leading whitespace | |
252 | line = line.lstrip() | |
253 | ||
254 | # We skip all options and sets | |
255 | if line.startswith("option") or line.startswith("set"): | |
256 | continue | |
257 | ||
258 | # Split by first space | |
259 | key, val = line.split(" ", 1) | |
260 | properties[key] = val | |
261 | ||
262 | return properties | |
263 | ||
264 | ||
86c9deb2 MT |
265 | class FixLeases(object): |
266 | cache = {} | |
267 | ||
268 | def __init__(self, path): | |
269 | self.path = path | |
270 | ||
271 | self._leases = self.cache[self.path] = self._parse() | |
272 | ||
273 | def __iter__(self): | |
274 | return iter(self._leases) | |
275 | ||
276 | def _parse(self): | |
277 | log.info("Reading fix leases from %s" % self.path) | |
278 | ||
279 | leases = [] | |
280 | now = datetime.datetime.utcnow() | |
281 | ||
282 | with open(self.path) as f: | |
283 | for line in f.readlines(): | |
284 | line = line.rstrip() | |
285 | ||
286 | try: | |
287 | hwaddr, ipaddr, enabled, a, b, c, hostname = line.split(",") | |
288 | except ValueError: | |
289 | log.warning("Could not parse line: %s" % line) | |
290 | continue | |
291 | ||
292 | # Skip any disabled leases | |
293 | if not enabled == "on": | |
294 | continue | |
295 | ||
296 | l = Lease(ipaddr, { | |
297 | "binding" : "state active", | |
298 | "client-hostname" : hostname, | |
299 | "hardware" : "ethernet %s" % hwaddr, | |
300 | "starts" : now.strftime("%w %Y/%m/%d %H:%M:%S"), | |
301 | "ends" : "never", | |
302 | }) | |
303 | leases.append(l) | |
304 | ||
305 | # Try finding any deleted leases | |
306 | for lease in self.cache.get(self.path, []): | |
307 | if lease in leases: | |
308 | continue | |
309 | ||
310 | # Free the deleted lease | |
311 | lease.free() | |
312 | leases.append(lease) | |
313 | ||
314 | return leases | |
315 | ||
316 | ||
0fbd7c3c MT |
317 | class Lease(object): |
318 | def __init__(self, ipaddr, properties): | |
319 | self.ipaddr = ipaddr | |
320 | self._properties = properties | |
321 | ||
322 | def __repr__(self): | |
323 | return "<%s %s for %s (%s)>" % (self.__class__.__name__, | |
324 | self.ipaddr, self.hwaddr, self.hostname) | |
325 | ||
326 | def __eq__(self, other): | |
327 | return self.ipaddr == other.ipaddr and self.hwaddr == other.hwaddr | |
328 | ||
329 | def __gt__(self, other): | |
330 | if not self.ipaddr == other.ipaddr: | |
331 | return | |
332 | ||
333 | if not self.hwaddr == other.hwaddr: | |
334 | return | |
335 | ||
336 | return self.time_starts > other.time_starts | |
337 | ||
338 | @property | |
339 | def binding_state(self): | |
340 | state = self._properties.get("binding") | |
341 | ||
342 | if state: | |
343 | state = state.split(" ", 1) | |
344 | return state[1] | |
345 | ||
86c9deb2 MT |
346 | def free(self): |
347 | self._properties.update({ | |
348 | "binding" : "state free", | |
349 | }) | |
350 | ||
0fbd7c3c MT |
351 | @property |
352 | def active(self): | |
353 | return self.binding_state == "active" | |
354 | ||
355 | @property | |
356 | def hwaddr(self): | |
357 | hardware = self._properties.get("hardware") | |
358 | ||
359 | if not hardware: | |
360 | return | |
361 | ||
362 | ethernet, address = hardware.split(" ", 1) | |
363 | ||
364 | return address | |
365 | ||
366 | @property | |
367 | def hostname(self): | |
368 | hostname = self._properties.get("client-hostname") | |
369 | ||
998e880b MT |
370 | if hostname is None: |
371 | return | |
372 | ||
0fbd7c3c | 373 | # Remove any "" |
998e880b | 374 | hostname = hostname.replace("\"", "") |
0fbd7c3c | 375 | |
998e880b MT |
376 | # Only return valid hostnames |
377 | m = re.match(r"^[A-Z0-9\-]{1,63}$", hostname, re.I) | |
378 | if m: | |
379 | return hostname | |
0fbd7c3c MT |
380 | |
381 | @property | |
382 | def domain(self): | |
74a5ab67 MT |
383 | # Load ethernet settings |
384 | ethernet_settings = self.read_settings("/var/ipfire/ethernet/settings") | |
385 | ||
386 | # Load DHCP settings | |
387 | dhcp_settings = self.read_settings("/var/ipfire/dhcp/settings") | |
388 | ||
389 | subnets = {} | |
390 | for zone in ("GREEN", "BLUE"): | |
391 | if not dhcp_settings.get("ENABLE_%s" % zone) == "on": | |
392 | continue | |
393 | ||
394 | netaddr = ethernet_settings.get("%s_NETADDRESS" % zone) | |
395 | submask = ethernet_settings.get("%s_NETMASK" % zone) | |
396 | ||
397 | subnet = ipaddress.ip_network("%s/%s" % (netaddr, submask)) | |
398 | domain = dhcp_settings.get("DOMAIN_NAME_%s" % zone) | |
399 | ||
400 | subnets[subnet] = domain | |
401 | ||
402 | address = ipaddress.ip_address(self.ipaddr) | |
403 | ||
404 | for subnet, domain in subnets.items(): | |
405 | if address in subnet: | |
406 | return domain | |
407 | ||
408 | # Fall back to localdomain if no match could be found | |
409 | return "localdomain" | |
410 | ||
411 | @staticmethod | |
412 | def read_settings(filename): | |
413 | settings = {} | |
414 | ||
415 | with open(filename) as f: | |
416 | for line in f.readlines(): | |
417 | # Remove line-breaks | |
418 | line = line.rstrip() | |
419 | ||
420 | k, v = line.split("=", 1) | |
421 | settings[k] = v | |
422 | ||
423 | return settings | |
0fbd7c3c MT |
424 | |
425 | @property | |
426 | def fqdn(self): | |
998e880b MT |
427 | if self.hostname: |
428 | return "%s.%s" % (self.hostname, self.domain) | |
0fbd7c3c MT |
429 | |
430 | @staticmethod | |
431 | def _parse_time(s): | |
432 | return datetime.datetime.strptime(s, "%w %Y/%m/%d %H:%M:%S") | |
433 | ||
434 | @property | |
435 | def time_starts(self): | |
436 | starts = self._properties.get("starts") | |
437 | ||
438 | if starts: | |
439 | return self._parse_time(starts) | |
440 | ||
441 | @property | |
442 | def time_ends(self): | |
443 | ends = self._properties.get("ends") | |
444 | ||
445 | if not ends or ends == "never": | |
446 | return | |
447 | ||
448 | return self._parse_time(ends) | |
449 | ||
450 | @property | |
451 | def expired(self): | |
452 | if not self.time_ends: | |
453 | return self.time_starts > datetime.datetime.utcnow() | |
454 | ||
455 | return self.time_starts > datetime.datetime.utcnow() > self.time_ends | |
456 | ||
457 | @property | |
458 | def rrset(self): | |
998e880b MT |
459 | # If the lease does not have a valid FQDN, we cannot create any RRs |
460 | if self.fqdn is None: | |
461 | return [] | |
462 | ||
0fbd7c3c MT |
463 | return [ |
464 | # Forward record | |
b8dd42b9 | 465 | (self.fqdn, "%s" % LOCAL_TTL, "IN A", self.ipaddr), |
0fbd7c3c MT |
466 | |
467 | # Reverse record | |
e22bcd38 MT |
468 | (ip_address_to_reverse_pointer(self.ipaddr), "%s" % LOCAL_TTL, |
469 | "IN PTR", self.fqdn), | |
0fbd7c3c MT |
470 | ] |
471 | ||
472 | ||
473 | class UnboundConfigWriter(object): | |
474 | def __init__(self, path): | |
475 | self.path = path | |
476 | ||
c7b83f9b | 477 | self._cached_leases = [] |
0fbd7c3c MT |
478 | |
479 | def update_dhcp_leases(self, leases): | |
d20ef9d7 MT |
480 | # Find any leases that have expired or do not exist any more |
481 | # but are still in the unbound local data | |
c7b83f9b | 482 | removed_leases = [l for l in self._cached_leases if not l in leases] |
d20ef9d7 | 483 | |
0fbd7c3c | 484 | # Find any leases that have been added |
c7b83f9b | 485 | new_leases = [l for l in leases if l not in self._cached_leases] |
0fbd7c3c MT |
486 | |
487 | # End here if nothing has changed | |
488 | if not new_leases and not removed_leases: | |
489 | return | |
490 | ||
0fbd7c3c MT |
491 | # Write out all leases |
492 | self.write_dhcp_leases(leases) | |
493 | ||
494 | # Update unbound about changes | |
c7b83f9b | 495 | for l in removed_leases: |
3ec5ba50 MT |
496 | try: |
497 | for name, ttl, type, content in l.rrset: | |
498 | log.debug("Removing records for %s" % name) | |
499 | self._control("local_data_remove", name) | |
500 | ||
501 | # If the lease cannot be removed we will try the next one | |
502 | except: | |
503 | continue | |
504 | ||
505 | # If the removal was successful, we will remove it from the cache | |
506 | else: | |
507 | self._cached_leases.remove(l) | |
0fbd7c3c MT |
508 | |
509 | for l in new_leases: | |
3ec5ba50 MT |
510 | try: |
511 | for rr in l.rrset: | |
512 | log.debug("Adding new record %s" % " ".join(rr)) | |
513 | self._control("local_data", *rr) | |
0fbd7c3c | 514 | |
3ec5ba50 MT |
515 | # If the lease cannot be added we will try the next one |
516 | except: | |
517 | continue | |
518 | ||
519 | # Add lease to cache when successfully added | |
520 | else: | |
521 | self._cached_leases.append(l) | |
0fbd7c3c MT |
522 | |
523 | def write_dhcp_leases(self, leases): | |
b666975e MT |
524 | with tempfile.NamedTemporaryFile(mode="w", delete=False) as f: |
525 | filename = f.name | |
526 | ||
0fbd7c3c MT |
527 | for l in leases: |
528 | for rr in l.rrset: | |
529 | f.write("local-data: \"%s\"\n" % " ".join(rr)) | |
530 | ||
b666975e MT |
531 | os.rename(filename, self.path) |
532 | ||
0fbd7c3c | 533 | def _control(self, *args): |
b8dd42b9 | 534 | command = ["unbound-control"] |
0fbd7c3c MT |
535 | command.extend(args) |
536 | ||
537 | try: | |
3ec5ba50 | 538 | subprocess.check_output(command) |
0fbd7c3c MT |
539 | |
540 | # Log any errors | |
541 | except subprocess.CalledProcessError as e: | |
542 | log.critical("Could not run %s, error code: %s: %s" % ( | |
543 | " ".join(command), e.returncode, e.output)) | |
544 | ||
3ec5ba50 MT |
545 | raise |
546 | ||
0fbd7c3c MT |
547 | |
548 | if __name__ == "__main__": | |
549 | parser = argparse.ArgumentParser(description="Bridge for DHCP Leases and Unbound DNS") | |
550 | ||
551 | # Daemon Stuff | |
552 | parser.add_argument("--daemon", "-d", action="store_true", | |
553 | help="Launch as daemon in background") | |
554 | parser.add_argument("--verbose", "-v", action="count", help="Be more verbose") | |
555 | ||
556 | # Paths | |
557 | parser.add_argument("--dhcp-leases", default="/var/state/dhcp/dhcpd.leases", | |
558 | metavar="PATH", help="Path to the DHCPd leases file") | |
559 | parser.add_argument("--unbound-leases", default="/etc/unbound/dhcp-leases.conf", | |
560 | metavar="PATH", help="Path to the unbound configuration file") | |
86c9deb2 MT |
561 | parser.add_argument("--fix-leases", default="/var/ipfire/dhcp/fixleases", |
562 | metavar="PATH", help="Path to the fix leases file") | |
7354d294 MT |
563 | parser.add_argument("--hosts", default="/var/ipfire/main/hosts", |
564 | metavar="PATH", help="Path to static hosts file") | |
0fbd7c3c MT |
565 | |
566 | # Parse command line arguments | |
567 | args = parser.parse_args() | |
568 | ||
569 | # Setup logging | |
570 | if args.verbose == 1: | |
571 | loglevel = logging.INFO | |
572 | elif args.verbose >= 2: | |
573 | loglevel = logging.DEBUG | |
574 | else: | |
575 | loglevel = logging.WARN | |
576 | ||
577 | setup_logging(loglevel) | |
578 | ||
7354d294 MT |
579 | bridge = UnboundDHCPLeasesBridge(args.dhcp_leases, args.fix_leases, |
580 | args.unbound_leases, args.hosts) | |
0fbd7c3c MT |
581 | |
582 | ctx = daemon.DaemonContext(detach_process=args.daemon) | |
583 | ctx.signal_map = { | |
584 | signal.SIGHUP : bridge.update_dhcp_leases, | |
585 | signal.SIGTERM : bridge.terminate, | |
586 | } | |
587 | ||
588 | with ctx: | |
589 | bridge.run() |