6a21af85395af68ac149b545d7f8009e5a3cd713
[oddments/ddns.git] / src / ddns / system.py
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 socket
25 import urllib
26 import urllib2
27
28 from __version__ import CLIENT_VERSION
29 from .errors import *
30 from i18n import _
31
32 # Initialize the logger.
33 import logging
34 logger = logging.getLogger("ddns.system")
35 logger.propagate = 1
36
37 class DDNSSystem(object):
38         """
39                 The DDNSSystem class adds a layer of abstraction
40                 between the ddns software and the system.
41         """
42
43         # The default useragent.
44         USER_AGENT = "IPFireDDNSUpdater/%s" % CLIENT_VERSION
45
46         def __init__(self, core):
47                 # Connection to the core of the program.
48                 self.core = core
49
50                 # Address cache.
51                 self.__addresses = {}
52
53                 # Find out on which distribution we are running.
54                 self.distro = self._get_distro_identifier()
55                 logger.debug(_("Running on distribution: %s") % self.distro)
56
57         @property
58         def proxy(self):
59                 proxy = self.core.settings.get("proxy")
60
61                 # Strip http:// at the beginning.
62                 if proxy and proxy.startswith("http://"):
63                         proxy = proxy[7:]
64
65                 return proxy
66
67         def get_local_ip_address(self, proto):
68                 # Legacy code for IPFire 2.
69                 if self.distro == "ipfire-2" and proto == "ipv4":
70                         try:
71                                 with open("/var/ipfire/red/local-ipaddress") as f:
72                                         return f.readline()
73
74                         except IOError, e:
75                                 # File not found
76                                 if e.errno == 2:
77                                         return
78
79                                 raise
80
81                 # XXX TODO
82                 raise NotImplementedError
83
84         def _guess_external_ip_address(self, url, timeout=10):
85                 """
86                         Sends a request to an external web server
87                         to determine the current default IP address.
88                 """
89                 try:
90                         response = self.send_request(url, timeout=timeout)
91
92                 # If the server could not be reached, we will return nothing.
93                 except DDNSNetworkError:
94                         return
95
96                 if not response.code == 200:
97                         return
98
99                 match = re.search(r"^Your IP address is: (.*)$", response.read())
100                 if match is None:
101                         return
102
103                 return match.group(1)
104
105         def guess_external_ip_address(self, family, **kwargs):
106                 if family == "ipv6":
107                         url = "http://checkip6.dns.lightningwirelabs.com"
108                 elif family == "ipv4":
109                         url = "http://checkip4.dns.lightningwirelabs.com"
110                 else:
111                         raise ValueError("unknown address family")
112
113                 return self._guess_external_ip_address(url, **kwargs)
114
115         def send_request(self, url, method="GET", data=None, username=None, password=None, timeout=30):
116                 assert method in ("GET", "POST")
117
118                 # Add all arguments in the data dict to the URL and escape them properly.
119                 if method == "GET" and data:
120                         query_args = self._format_query_args(data)
121                         data = None
122
123                         if "?" in url:
124                                 url = "%s&%s" % (url, query_args)
125                         else:
126                                 url = "%s?%s" % (url, query_args)
127
128                 logger.debug("Sending request (%s): %s" % (method, url))
129                 if data:
130                         logger.debug("  data: %s" % data)
131
132                 req = urllib2.Request(url, data=data)
133
134                 if username and password:
135                         basic_auth_header = self._make_basic_auth_header(username, password)
136                         req.add_header("Authorization", "Basic %s" % basic_auth_header)
137
138                 # Set the user agent.
139                 req.add_header("User-Agent", self.USER_AGENT)
140
141                 # All requests should not be cached anywhere.
142                 req.add_header("Pragma", "no-cache")
143
144                 # Set the upstream proxy if needed.
145                 if self.proxy:
146                         logger.debug("Using proxy: %s" % self.proxy)
147
148                         # Configure the proxy for this request.
149                         req.set_proxy(self.proxy, "http")
150
151                 assert req.get_method() == method
152
153                 logger.debug(_("Request header:"))
154                 for k, v in req.headers.items():
155                         logger.debug("  %s: %s" % (k, v))
156
157                 try:
158                         resp = urllib2.urlopen(req, timeout=timeout)
159
160                         # Log response header.
161                         logger.debug(_("Response header (Status Code %s):") % resp.code)
162                         for k, v in resp.info().items():
163                                 logger.debug("  %s: %s" % (k, v))
164
165                         # Return the entire response object.
166                         return resp
167
168                 except urllib2.HTTPError, e:
169                         # Log response header.
170                         logger.debug(_("Response header (Status Code %s):") % e.code)
171                         for k, v in e.hdrs.items():
172                                 logger.debug("  %s: %s" % (k, v))
173
174                         # 400 - Bad request
175                         if e.code == 400:
176                                 raise DDNSRequestError(e.reason)
177
178                         # 401 - Authorization Required
179                         # 403 - Forbidden
180                         elif e.code in (401, 403):
181                                 raise DDNSAuthenticationError(e.reason)
182
183                         # 404 - Not found
184                         # Either the provider has changed the API, or
185                         # there is an error on the server
186                         elif e.code == 404:
187                                 raise DDNSNotFound(e.reason)
188
189                         # 500 - Internal Server Error
190                         elif e.code == 500:
191                                 raise DDNSInternalServerError(e.reason)
192
193                         # 503 - Service Unavailable
194                         elif e.code == 503:
195                                 raise DDNSServiceUnavailableError(e.reason)
196
197                         # Raise all other unhandled exceptions.
198                         raise
199
200                 except urllib2.URLError, e:
201                         if e.reason:
202                                 # Name or service not known
203                                 if e.reason.errno == -2:
204                                         raise DDNSResolveError
205
206                                 # Network Unreachable (e.g. no IPv6 access)
207                                 if e.reason.errno == 101:
208                                         raise DDNSNetworkUnreachableError
209
210                                 # Connection Refused
211                                 elif e.reason.errno == 111:
212                                         raise DDNSConnectionRefusedError
213
214                                 # No route to host
215                                 elif e.reason.errno == 113:
216                                         raise DDNSNoRouteToHostError(req.host)
217
218                         # Raise all other unhandled exceptions.
219                         raise
220
221                 except socket.timeout, e:
222                         logger.debug(_("Connection timeout"))
223
224                         raise DDNSConnectionTimeoutError
225
226         def _format_query_args(self, data):
227                 args = []
228
229                 for k, v in data.items():
230                         arg = "%s=%s" % (k, urllib.quote(v))
231                         args.append(arg)
232
233                 return "&".join(args)
234
235         def _make_basic_auth_header(self, username, password):
236                 authstring = "%s:%s" % (username, password)
237
238                 # Encode authorization data in base64.
239                 authstring = base64.encodestring(authstring)
240
241                 # Remove any newline characters.
242                 authstring = authstring.replace("\n", "")
243
244                 return authstring
245
246         def get_address(self, proto):
247                 """
248                         Returns the current IP address for
249                         the given IP protocol.
250                 """
251                 try:
252                         return self.__addresses[proto]
253
254                 # IP is currently unknown and needs to be retrieved.
255                 except KeyError:
256                         self.__addresses[proto] = address = \
257                                 self._get_address(proto)
258
259                         return address
260
261         def _get_address(self, proto):
262                 assert proto in ("ipv6", "ipv4")
263
264                 # IPFire 2 does not support IPv6.
265                 if self.distro == "ipfire-2" and proto == "ipv6":
266                         return
267
268                 # Check if the external IP address should be guessed from
269                 # a remote server.
270                 guess_ip = self.core.settings.get("guess_external_ip", "true")
271                 guess_ip = guess_ip in ("true", "yes", "1")
272
273                 # If the external IP address should be used, we just do that.
274                 if guess_ip:
275                         return self.guess_external_ip_address(proto)
276
277                 # Get the local IP address.
278                 local_ip_address = self.get_local_ip_address(proto)
279
280                 # If the local IP address is not usable, we must guess
281                 # the correct IP address...
282                 if not self._is_usable_ip_address(proto, local_ip_address):
283                         local_ip_address = self.guess_external_ip_address(proto)
284
285                 return local_ip_address
286
287         def _is_usable_ip_address(self, proto, address):
288                 """
289                         Returns True is the local IP address is usable
290                         for dynamic DNS (i.e. is not a RFC1918 address or similar).
291                 """
292                 if proto == "ipv4":
293                         # This is not the most perfect solution to match
294                         # these addresses, but instead of pulling in an entire
295                         # library to handle the IP addresses better, we match
296                         # with regular expressions instead.
297                         matches = (
298                                 # RFC1918 address space
299                                 r"^10\.\d+\.\d+\.\d+$",
300                                 r"^192\.168\.\d+\.\d+$",
301                                 r"^172\.(1[6-9]|2[0-9]|31)\.\d+\.\d+$",
302
303                                 # Dual Stack Lite address space
304                                 r"^100\.(6[4-9]|[7-9][0-9]|1[01][0-9]|12[0-7])\.\d+\.\d+$",
305                         )
306
307                         for match in matches:
308                                 m = re.match(match, address)
309                                 if m is None:
310                                         continue
311
312                                 # Found a match. IP address is not usable.
313                                 return False
314
315                 # In all other cases, return OK.
316                 return True
317
318         def resolve(self, hostname, proto=None):
319                 addresses = []
320
321                 if proto is None:
322                         family = 0
323                 elif proto == "ipv6":
324                         family = socket.AF_INET6
325                 elif proto == "ipv4":
326                         family = socket.AF_INET
327                 else:
328                         raise ValueError("Protocol not supported: %s" % proto)
329
330                 # Resolve the host address.
331                 try:
332                         response = socket.getaddrinfo(hostname, None, family)
333                 except socket.gaierror, e:
334                         # Name or service not known
335                         if e.errno == -2:
336                                 return []
337
338                         # Temporary failure in name resolution
339                         elif e.errno == -3:
340                                 raise DDNSResolveError(hostname)
341
342                         # No record for requested family available (e.g. no AAAA)
343                         elif e.errno == -5:
344                                 return []
345
346                         raise
347
348                 # Handle responses.
349                 for family, socktype, proto, canonname, sockaddr in response:
350                         # IPv6
351                         if family == socket.AF_INET6:
352                                 address, port, flow_info, scope_id = sockaddr
353
354                                 # Only use the global scope.
355                                 if not scope_id == 0:
356                                         continue
357
358                         # IPv4
359                         elif family == socket.AF_INET:
360                                 address, port = sockaddr
361
362                         # Ignore everything else...
363                         else:
364                                 continue
365
366                         # Add to repsonse list if not already in there.
367                         if not address in addresses:
368                                 addresses.append(address)
369
370                 return addresses
371
372         def _get_distro_identifier(self):
373                 """
374                         Returns a unique identifier for the distribution
375                         we are running on.
376                 """
377                 os_release = self.__parse_os_release()
378                 if os_release:
379                         return os_release
380
381                 system_release = self.__parse_system_release()
382                 if system_release:
383                         return system_release
384
385                 # If nothing else could be found, we return
386                 # just "unknown".
387                 return "unknown"
388
389         def __parse_os_release(self):
390                 """
391                         Tries to parse /etc/os-release and
392                         returns a unique distribution identifier
393                         if the file exists.
394                 """
395                 try:
396                         f = open("/etc/os-release", "r")
397                 except IOError, e:
398                         # File not found
399                         if e.errno == 2:
400                                 return
401
402                         raise
403
404                 os_release = {}
405                 with f:
406                         for line in f.readlines():
407                                 m = re.match(r"^([A-Z\_]+)=(.*)$", line)
408                                 if m is None:
409                                         continue
410
411                                 os_release[m.group(1)] = m.group(2)
412
413                 try:
414                         return "%(ID)s-%(VERSION_ID)s" % os_release
415                 except KeyError:
416                         return
417
418         def __parse_system_release(self):
419                 """
420                         Tries to parse /etc/system-release and
421                         returns a unique distribution identifier
422                         if the file exists.
423                 """
424                 try:
425                         f = open("/etc/system-release", "r")
426                 except IOError, e:
427                         # File not found
428                         if e.errno == 2:
429                                 return
430
431                         raise
432
433                 with f:
434                         # Read first line
435                         line = f.readline()
436
437                         # Check for IPFire systems
438                         m = re.match(r"^IPFire (\d).(\d+)", line)
439                         if m:
440                                 return "ipfire-%s" % m.group(1)