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1 | #!/usr/bin/python | |
2 | ############################################################################### | |
3 | # # | |
4 | # ddns - A dynamic DNS client for IPFire # | |
5 | # Copyright (C) 2012 IPFire development team # | |
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 base64 | |
23 | import re | |
24 | import ssl | |
25 | import socket | |
26 | import urllib | |
27 | import urllib2 | |
28 | ||
29 | from __version__ import CLIENT_VERSION | |
30 | from .errors import * | |
31 | from i18n import _ | |
32 | ||
33 | # Initialize the logger. | |
34 | import logging | |
35 | logger = logging.getLogger("ddns.system") | |
36 | logger.propagate = 1 | |
37 | ||
38 | class DDNSSystem(object): | |
39 | """ | |
40 | The DDNSSystem class adds a layer of abstraction | |
41 | between the ddns software and the system. | |
42 | """ | |
43 | ||
44 | # The default useragent. | |
45 | USER_AGENT = "IPFireDDNSUpdater/%s" % CLIENT_VERSION | |
46 | ||
47 | def __init__(self, core): | |
48 | # Connection to the core of the program. | |
49 | self.core = core | |
50 | ||
51 | # Address cache. | |
52 | self.__addresses = {} | |
53 | ||
54 | # Find out on which distribution we are running. | |
55 | self.distro = self._get_distro_identifier() | |
56 | logger.debug(_("Running on distribution: %s") % self.distro) | |
57 | ||
58 | @property | |
59 | def proxy(self): | |
60 | proxy = self.core.settings.get("proxy") | |
61 | ||
62 | # Strip http:// at the beginning. | |
63 | if proxy and proxy.startswith("http://"): | |
64 | proxy = proxy[7:] | |
65 | ||
66 | return proxy | |
67 | ||
68 | def get_local_ip_address(self, proto): | |
69 | ip_address = self._get_local_ip_address(proto) | |
70 | ||
71 | # Check if the IP address is usable and only return it then | |
72 | if self._is_usable_ip_address(proto, ip_address): | |
73 | return ip_address | |
74 | ||
75 | def _get_local_ip_address(self, proto): | |
76 | # Legacy code for IPFire 2. | |
77 | if self.distro == "ipfire-2" and proto == "ipv4": | |
78 | try: | |
79 | with open("/var/ipfire/red/local-ipaddress") as f: | |
80 | return f.readline() | |
81 | ||
82 | except IOError, e: | |
83 | # File not found | |
84 | if e.errno == 2: | |
85 | return | |
86 | ||
87 | raise | |
88 | ||
89 | # XXX TODO | |
90 | raise NotImplementedError | |
91 | ||
92 | def _guess_external_ip_address(self, url, timeout=10): | |
93 | """ | |
94 | Sends a request to an external web server | |
95 | to determine the current default IP address. | |
96 | """ | |
97 | try: | |
98 | response = self.send_request(url, timeout=timeout) | |
99 | ||
100 | # If the server could not be reached, we will return nothing. | |
101 | except DDNSNetworkError: | |
102 | return | |
103 | ||
104 | if not response.code == 200: | |
105 | return | |
106 | ||
107 | match = re.search(r"^Your IP address is: (.*)$", response.read()) | |
108 | if match is None: | |
109 | return | |
110 | ||
111 | return match.group(1) | |
112 | ||
113 | def guess_external_ip_address(self, family, **kwargs): | |
114 | if family == "ipv6": | |
115 | url = "http://checkip6.dns.lightningwirelabs.com" | |
116 | elif family == "ipv4": | |
117 | url = "http://checkip4.dns.lightningwirelabs.com" | |
118 | else: | |
119 | raise ValueError("unknown address family") | |
120 | ||
121 | return self._guess_external_ip_address(url, **kwargs) | |
122 | ||
123 | def send_request(self, url, method="GET", data=None, username=None, password=None, timeout=30): | |
124 | assert method in ("GET", "POST") | |
125 | ||
126 | # Add all arguments in the data dict to the URL and escape them properly. | |
127 | if method == "GET" and data: | |
128 | query_args = self._format_query_args(data) | |
129 | data = None | |
130 | ||
131 | if "?" in url: | |
132 | url = "%s&%s" % (url, query_args) | |
133 | else: | |
134 | url = "%s?%s" % (url, query_args) | |
135 | ||
136 | logger.debug("Sending request (%s): %s" % (method, url)) | |
137 | if data: | |
138 | logger.debug(" data: %s" % data) | |
139 | ||
140 | req = urllib2.Request(url, data=data) | |
141 | ||
142 | if username and password: | |
143 | basic_auth_header = self._make_basic_auth_header(username, password) | |
144 | req.add_header("Authorization", "Basic %s" % basic_auth_header) | |
145 | ||
146 | # Set the user agent. | |
147 | req.add_header("User-Agent", self.USER_AGENT) | |
148 | ||
149 | # All requests should not be cached anywhere. | |
150 | req.add_header("Pragma", "no-cache") | |
151 | ||
152 | # Set the upstream proxy if needed. | |
153 | if self.proxy: | |
154 | logger.debug("Using proxy: %s" % self.proxy) | |
155 | ||
156 | # Configure the proxy for this request. | |
157 | req.set_proxy(self.proxy, "http") | |
158 | ||
159 | assert req.get_method() == method | |
160 | ||
161 | logger.debug(_("Request header:")) | |
162 | for k, v in req.headers.items(): | |
163 | logger.debug(" %s: %s" % (k, v)) | |
164 | ||
165 | try: | |
166 | resp = urllib2.urlopen(req, timeout=timeout) | |
167 | ||
168 | # Log response header. | |
169 | logger.debug(_("Response header (Status Code %s):") % resp.code) | |
170 | for k, v in resp.info().items(): | |
171 | logger.debug(" %s: %s" % (k, v)) | |
172 | ||
173 | # Return the entire response object. | |
174 | return resp | |
175 | ||
176 | except urllib2.HTTPError, e: | |
177 | # Log response header. | |
178 | logger.debug(_("Response header (Status Code %s):") % e.code) | |
179 | for k, v in e.hdrs.items(): | |
180 | logger.debug(" %s: %s" % (k, v)) | |
181 | ||
182 | # 400 - Bad request | |
183 | if e.code == 400: | |
184 | raise DDNSRequestError(e.reason) | |
185 | ||
186 | # 401 - Authorization Required | |
187 | # 403 - Forbidden | |
188 | elif e.code in (401, 403): | |
189 | raise DDNSAuthenticationError(e.reason) | |
190 | ||
191 | # 404 - Not found | |
192 | # Either the provider has changed the API, or | |
193 | # there is an error on the server | |
194 | elif e.code == 404: | |
195 | raise DDNSNotFound(e.reason) | |
196 | ||
197 | # 500 - Internal Server Error | |
198 | elif e.code == 500: | |
199 | raise DDNSInternalServerError(e.reason) | |
200 | ||
201 | # 503 - Service Unavailable | |
202 | elif e.code == 503: | |
203 | raise DDNSServiceUnavailableError(e.reason) | |
204 | ||
205 | # Raise all other unhandled exceptions. | |
206 | raise | |
207 | ||
208 | except urllib2.URLError, e: | |
209 | if e.reason: | |
210 | # Handle SSL errors | |
211 | if isinstance(e.reason, ssl.SSLError): | |
212 | e = e.reason | |
213 | ||
214 | if e.reason == "CERTIFICATE_VERIFY_FAILED": | |
215 | raise DDNSCertificateError | |
216 | ||
217 | # Raise all other SSL errors | |
218 | raise DDNSSSLError(e.reason) | |
219 | ||
220 | # Name or service not known | |
221 | if e.reason.errno == -2: | |
222 | raise DDNSResolveError | |
223 | ||
224 | # Network Unreachable (e.g. no IPv6 access) | |
225 | if e.reason.errno == 101: | |
226 | raise DDNSNetworkUnreachableError | |
227 | ||
228 | # Connection Refused | |
229 | elif e.reason.errno == 111: | |
230 | raise DDNSConnectionRefusedError | |
231 | ||
232 | # No route to host | |
233 | elif e.reason.errno == 113: | |
234 | raise DDNSNoRouteToHostError(req.host) | |
235 | ||
236 | # Raise all other unhandled exceptions. | |
237 | raise | |
238 | ||
239 | except socket.timeout, e: | |
240 | logger.debug(_("Connection timeout")) | |
241 | ||
242 | raise DDNSConnectionTimeoutError | |
243 | ||
244 | def _format_query_args(self, data): | |
245 | args = [] | |
246 | ||
247 | for k, v in data.items(): | |
248 | arg = "%s=%s" % (k, urllib.quote(v)) | |
249 | args.append(arg) | |
250 | ||
251 | return "&".join(args) | |
252 | ||
253 | def _make_basic_auth_header(self, username, password): | |
254 | authstring = "%s:%s" % (username, password) | |
255 | ||
256 | # Encode authorization data in base64. | |
257 | authstring = base64.encodestring(authstring) | |
258 | ||
259 | # Remove any newline characters. | |
260 | authstring = authstring.replace("\n", "") | |
261 | ||
262 | return authstring | |
263 | ||
264 | def get_address(self, proto): | |
265 | """ | |
266 | Returns the current IP address for | |
267 | the given IP protocol. | |
268 | """ | |
269 | try: | |
270 | return self.__addresses[proto] | |
271 | ||
272 | # IP is currently unknown and needs to be retrieved. | |
273 | except KeyError: | |
274 | self.__addresses[proto] = address = \ | |
275 | self._get_address(proto) | |
276 | ||
277 | return address | |
278 | ||
279 | def _get_address(self, proto): | |
280 | assert proto in ("ipv6", "ipv4") | |
281 | ||
282 | # IPFire 2 does not support IPv6. | |
283 | if self.distro == "ipfire-2" and proto == "ipv6": | |
284 | return | |
285 | ||
286 | # Check if the external IP address should be guessed from | |
287 | # a remote server. | |
288 | guess_ip = self.core.settings.get("guess_external_ip", "true") | |
289 | guess_ip = guess_ip in ("true", "yes", "1") | |
290 | ||
291 | # Get the local IP address. | |
292 | local_ip_address = None | |
293 | ||
294 | if not guess_ip: | |
295 | try: | |
296 | local_ip_address = self.get_local_ip_address(proto) | |
297 | except NotImplementedError: | |
298 | logger.warning(_("Falling back to check the IP address with help of a public server")) | |
299 | ||
300 | # If no local IP address could be determined, we will fall back to the guess | |
301 | # it with help of an external server... | |
302 | if not local_ip_address: | |
303 | local_ip_address = self.guess_external_ip_address(proto) | |
304 | ||
305 | return local_ip_address | |
306 | ||
307 | def _is_usable_ip_address(self, proto, address): | |
308 | """ | |
309 | Returns True is the local IP address is usable | |
310 | for dynamic DNS (i.e. is not a RFC1918 address or similar). | |
311 | """ | |
312 | if proto == "ipv4": | |
313 | # This is not the most perfect solution to match | |
314 | # these addresses, but instead of pulling in an entire | |
315 | # library to handle the IP addresses better, we match | |
316 | # with regular expressions instead. | |
317 | matches = ( | |
318 | # RFC1918 address space | |
319 | r"^10\.\d+\.\d+\.\d+$", | |
320 | r"^192\.168\.\d+\.\d+$", | |
321 | r"^172\.(1[6-9]|2[0-9]|31)\.\d+\.\d+$", | |
322 | ||
323 | # Dual Stack Lite address space | |
324 | r"^100\.(6[4-9]|[7-9][0-9]|1[01][0-9]|12[0-7])\.\d+\.\d+$", | |
325 | ) | |
326 | ||
327 | for match in matches: | |
328 | m = re.match(match, address) | |
329 | if m is None: | |
330 | continue | |
331 | ||
332 | # Found a match. IP address is not usable. | |
333 | return False | |
334 | ||
335 | # In all other cases, return OK. | |
336 | return True | |
337 | ||
338 | def resolve(self, hostname, proto=None): | |
339 | addresses = [] | |
340 | ||
341 | if proto is None: | |
342 | family = 0 | |
343 | elif proto == "ipv6": | |
344 | family = socket.AF_INET6 | |
345 | elif proto == "ipv4": | |
346 | family = socket.AF_INET | |
347 | else: | |
348 | raise ValueError("Protocol not supported: %s" % proto) | |
349 | ||
350 | # Resolve the host address. | |
351 | try: | |
352 | response = socket.getaddrinfo(hostname, None, family) | |
353 | except socket.gaierror, e: | |
354 | # Name or service not known | |
355 | if e.errno == -2: | |
356 | return [] | |
357 | ||
358 | # Temporary failure in name resolution | |
359 | elif e.errno == -3: | |
360 | raise DDNSResolveError(hostname) | |
361 | ||
362 | # No record for requested family available (e.g. no AAAA) | |
363 | elif e.errno == -5: | |
364 | return [] | |
365 | ||
366 | raise | |
367 | ||
368 | # Handle responses. | |
369 | for family, socktype, proto, canonname, sockaddr in response: | |
370 | # IPv6 | |
371 | if family == socket.AF_INET6: | |
372 | address, port, flow_info, scope_id = sockaddr | |
373 | ||
374 | # Only use the global scope. | |
375 | if not scope_id == 0: | |
376 | continue | |
377 | ||
378 | # IPv4 | |
379 | elif family == socket.AF_INET: | |
380 | address, port = sockaddr | |
381 | ||
382 | # Ignore everything else... | |
383 | else: | |
384 | continue | |
385 | ||
386 | # Add to repsonse list if not already in there. | |
387 | if not address in addresses: | |
388 | addresses.append(address) | |
389 | ||
390 | return addresses | |
391 | ||
392 | def _get_distro_identifier(self): | |
393 | """ | |
394 | Returns a unique identifier for the distribution | |
395 | we are running on. | |
396 | """ | |
397 | os_release = self.__parse_os_release() | |
398 | if os_release: | |
399 | return os_release | |
400 | ||
401 | system_release = self.__parse_system_release() | |
402 | if system_release: | |
403 | return system_release | |
404 | ||
405 | # If nothing else could be found, we return | |
406 | # just "unknown". | |
407 | return "unknown" | |
408 | ||
409 | def __parse_os_release(self): | |
410 | """ | |
411 | Tries to parse /etc/os-release and | |
412 | returns a unique distribution identifier | |
413 | if the file exists. | |
414 | """ | |
415 | try: | |
416 | f = open("/etc/os-release", "r") | |
417 | except IOError, e: | |
418 | # File not found | |
419 | if e.errno == 2: | |
420 | return | |
421 | ||
422 | raise | |
423 | ||
424 | os_release = {} | |
425 | with f: | |
426 | for line in f.readlines(): | |
427 | m = re.match(r"^([A-Z\_]+)=(.*)$", line) | |
428 | if m is None: | |
429 | continue | |
430 | ||
431 | os_release[m.group(1)] = m.group(2) | |
432 | ||
433 | try: | |
434 | return "%(ID)s-%(VERSION_ID)s" % os_release | |
435 | except KeyError: | |
436 | return | |
437 | ||
438 | def __parse_system_release(self): | |
439 | """ | |
440 | Tries to parse /etc/system-release and | |
441 | returns a unique distribution identifier | |
442 | if the file exists. | |
443 | """ | |
444 | try: | |
445 | f = open("/etc/system-release", "r") | |
446 | except IOError, e: | |
447 | # File not found | |
448 | if e.errno == 2: | |
449 | return | |
450 | ||
451 | raise | |
452 | ||
453 | with f: | |
454 | # Read first line | |
455 | line = f.readline() | |
456 | ||
457 | # Check for IPFire systems | |
458 | m = re.match(r"^IPFire (\d).(\d+)", line) | |
459 | if m: | |
460 | return "ipfire-%s" % m.group(1) |