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                 # Find out on which distribution we are running.
  51                 self.distro = self._get_distro_identifier()
  52                 logger.debug(_("Running on distribution: %s") % self.distro)
  53
  54         @property
  55         def proxy(self):
  56                 proxy = self.core.settings.get("proxy")
  57
  58                 # Strip http:// at the beginning.
  59                 if proxy and proxy.startswith("http://"):
  60                         proxy = proxy[7:]
  61
  62                 return proxy
  63
  64         def get_local_ipv6_address(self):
  65                 return # XXX TODO
  66
  67         def get_local_ipv4_address(self):
  68                 if self.distro == "ipfire-2":
  69                         try:
  70                                 with open("/var/ipfire/red/local-ipaddress") as f:
  71                                         return f.readline()
  72
  73                         except IOError, e:
  74                                 # File not found
  75                                 if e.errno == 2:
  76                                         return
  77
  78                                 raise
  79
  80                 return # XXX TODO
  81
  82         def _guess_external_ip_address(self, url, timeout=10):
  83                 """
  84                         Sends a request to an external web server
  85                         to determine the current default IP address.
  86                 """
  87                 try:
  88                         response = self.send_request(url, timeout=timeout)
  89
  90                 # If the server could not be reached, we will return nothing.
  91                 except DDNSNetworkError:
  92                         return
  93
  94                 if not response.code == 200:
  95                         return
  96
  97                 match = re.search(r"^Your IP address is: (.*)$", response.read())
  98                 if match is None:
  99                         return
 100
 101                 return match.group(1)
 102
 103         def guess_external_ipv6_address(self):
 104                 """
 105                         Sends a request to the internet to determine
 106                         the public IPv6 address.
 107                 """
 108                 return self._guess_external_ip_address("http://checkip6.dns.lightningwirelabs.com")
 109
 110         def guess_external_ipv4_address(self):
 111                 """
 112                         Sends a request to the internet to determine
 113                         the public IPv4 address.
 114                 """
 115                 return self._guess_external_ip_address("http://checkip4.dns.lightningwirelabs.com")
 116
 117         def send_request(self, url, method="GET", data=None, username=None, password=None, timeout=30):
 118                 assert method in ("GET", "POST")
 119
 120                 # Add all arguments in the data dict to the URL and escape them properly.
 121                 if method == "GET" and data:
 122                         query_args = self._format_query_args(data)
 123                         data = None
 124
 125                         if "?" in url:
 126                                 url = "%s&%s" % (url, query_args)
 127                         else:
 128                                 url = "%s?%s" % (url, query_args)
 129
 130                 logger.debug("Sending request (%s): %s" % (method, url))
 131                 if data:
 132                         logger.debug("  data: %s" % data)
 133
 134                 req = urllib2.Request(url, data=data)
 135
 136                 if username and password:
 137                         basic_auth_header = self._make_basic_auth_header(username, password)
 138                         req.add_header("Authorization", "Basic %s" % basic_auth_header)
 139
 140                 # Set the user agent.
 141                 req.add_header("User-Agent", self.USER_AGENT)
 142
 143                 # All requests should not be cached anywhere.
 144                 req.add_header("Pragma", "no-cache")
 145
 146                 # Set the upstream proxy if needed.
 147                 if self.proxy:
 148                         logger.debug("Using proxy: %s" % self.proxy)
 149
 150                         # Configure the proxy for this request.
 151                         req.set_proxy(self.proxy, "http")
 152
 153                 assert req.get_method() == method
 154
 155                 logger.debug(_("Request header:"))
 156                 for k, v in req.headers.items():
 157                         logger.debug("  %s: %s" % (k, v))
 158
 159                 try:
 160                         resp = urllib2.urlopen(req, timeout=timeout)
 161
 162                         # Log response header.
 163                         logger.debug(_("Response header (Status Code %s):") % resp.code)
 164                         for k, v in resp.info().items():
 165                                 logger.debug("  %s: %s" % (k, v))
 166
 167                         # Return the entire response object.
 168                         return resp
 169
 170                 except urllib2.HTTPError, e:
 171                         # 400 - Bad request
 172                         if e.code == 400:
 173                                 raise DDNSRequestError(e.reason)
 174
 175                         # 401 - Authorization Required
 176                         # 403 - Forbidden
 177                         elif e.code in (401, 403):
 178                                 raise DDNSAuthenticationError(e.reason)
 179
 180                         # 500 - Internal Server Error
 181                         elif e.code == 500:
 182                                 raise DDNSInternalServerError(e.reason)
 183
 184                         # 503 - Service Unavailable
 185                         elif e.code == 503:
 186                                 raise DDNSServiceUnavailableError(e.reason)
 187
 188                         # Raise all other unhandled exceptions.
 189                         raise
 190
 191                 except urllib2.URLError, e:
 192                         if e.reason:
 193                                 # Network Unreachable (e.g. no IPv6 access)
 194                                 if e.reason.errno == 101:
 195                                         raise DDNSNetworkUnreachableError
 196                                 elif e.reason.errno == 111:
 197                                         raise DDNSConnectionRefusedError
 198
 199                         # Raise all other unhandled exceptions.
 200                         raise
 201
 202                 except socket.timeout, e:
 203                         logger.debug(_("Connection timeout"))
 204
 205                         raise DDNSConnectionTimeoutError
 206
 207         def _format_query_args(self, data):
 208                 args = []
 209
 210                 for k, v in data.items():
 211                         arg = "%s=%s" % (k, urllib.quote(v))
 212                         args.append(arg)
 213
 214                 return "&".join(args)
 215
 216         def _make_basic_auth_header(self, username, password):
 217                 authstring = "%s:%s" % (username, password)
 218
 219                 # Encode authorization data in base64.
 220                 authstring = base64.encodestring(authstring)
 221
 222                 # Remove any newline characters.
 223                 authstring = authstring.replace("\n", "")
 224
 225                 return authstring
 226
 227         def get_address(self, proto):
 228                 assert proto in ("ipv6", "ipv4")
 229
 230                 # IPFire 2 does not support IPv6.
 231                 if self.distro == "ipfire-2" and proto == "ipv6":
 232                         return
 233
 234                 # Check if the external IP address should be guessed from
 235                 # a remote server.
 236                 guess_ip = self.core.settings.get("guess_external_ip", "true")
 237
 238                 # If the external IP address should be used, we just do
 239                 # that.
 240                 if guess_ip in ("true", "yes", "1"):
 241                         if proto == "ipv6":
 242                                 return self.guess_external_ipv6_address()
 243
 244                         elif proto == "ipv4":
 245                                 return self.guess_external_ipv4_address()
 246
 247                 # Get the local IP addresses.
 248                 else:
 249                         if proto == "ipv6":
 250                                 return self.get_local_ipv6_address()
 251                         elif proto == "ipv4":
 252                                 return self.get_local_ipv4_address()
 253
 254         def resolve(self, hostname, proto=None):
 255                 addresses = []
 256
 257                 if proto is None:
 258                         family = 0
 259                 elif proto == "ipv6":
 260                         family = socket.AF_INET6
 261                 elif proto == "ipv4":
 262                         family = socket.AF_INET
 263                 else:
 264                         raise ValueError("Protocol not supported: %s" % proto)
 265
 266                 # Resolve the host address.
 267                 try:
 268                         response = socket.getaddrinfo(hostname, None, family)
 269                 except socket.gaierror, e:
 270                         # Name or service not known
 271                         if e.errno == -2:
 272                                 return []
 273
 274                         # No record for requested family available (e.g. no AAAA)
 275                         elif e.errno == -5:
 276                                 return []
 277
 278                         raise
 279
 280                 # Handle responses.
 281                 for family, socktype, proto, canonname, sockaddr in response:
 282                         # IPv6
 283                         if family == socket.AF_INET6:
 284                                 address, port, flow_info, scope_id = sockaddr
 285
 286                                 # Only use the global scope.
 287                                 if not scope_id == 0:
 288                                         continue
 289
 290                         # IPv4
 291                         elif family == socket.AF_INET:
 292                                 address, port = sockaddr
 293
 294                         # Ignore everything else...
 295                         else:
 296                                 continue
 297
 298                         # Add to repsonse list if not already in there.
 299                         if not address in addresses:
 300                                 addresses.append(address)
 301
 302                 return addresses
 303
 304         def _get_distro_identifier(self):
 305                 """
 306                         Returns a unique identifier for the distribution
 307                         we are running on.
 308                 """
 309                 os_release = self.__parse_os_release()
 310                 if os_release:
 311                         return os_release
 312
 313                 system_release = self.__parse_system_release()
 314                 if system_release:
 315                         return system_release
 316
 317                 # If nothing else could be found, we return
 318                 # just "unknown".
 319                 return "unknown"
 320
 321         def __parse_os_release(self):
 322                 """
 323                         Tries to parse /etc/os-release and
 324                         returns a unique distribution identifier
 325                         if the file exists.
 326                 """
 327                 try:
 328                         f = open("/etc/os-release", "r")
 329                 except IOError, e:
 330                         # File not found
 331                         if e.errno == 2:
 332                                 return
 333
 334                         raise
 335
 336                 os_release = {}
 337                 with f:
 338                         for line in f.readlines():
 339                                 m = re.match(r"^([A-Z\_]+)=(.*)$", line)
 340                                 if m is None:
 341                                         continue
 342
 343                                 os_release[m.group(1)] = m.group(2)
 344
 345                 try:
 346                         return "%(ID)s-%(VERSION_ID)s" % os_release
 347                 except KeyError:
 348                         return
 349
 350         def __parse_system_release(self):
 351                 """
 352                         Tries to parse /etc/system-release and
 353                         returns a unique distribution identifier
 354                         if the file exists.
 355                 """
 356                 try:
 357                         f = open("/etc/system-release", "r")
 358                 except IOError, e:
 359                         # File not found
 360                         if e.errno == 2:
 361                                 return
 362
 363                         raise
 364
 365                 with f:
 366                         # Read first line
 367                         line = f.readline()
 368
 369                         # Check for IPFire systems
 370                         m = re.match(r"^IPFire (\d).(\d+)", line)
 371                         if m:
 372                                 return "ipfire-%s" % m.group(1)