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_ipv6_address(self):
  68                 return # XXX TODO
  69
  70         def get_local_ipv4_address(self):
  71                 if self.distro == "ipfire-2":
  72                         try:
  73                                 with open("/var/ipfire/red/local-ipaddress") as f:
  74                                         return f.readline()
  75
  76                         except IOError, e:
  77                                 # File not found
  78                                 if e.errno == 2:
  79                                         return
  80
  81                                 raise
  82
  83                 return # XXX TODO
  84
  85         def _guess_external_ip_address(self, url, timeout=10):
  86                 """
  87                         Sends a request to an external web server
  88                         to determine the current default IP address.
  89                 """
  90                 try:
  91                         response = self.send_request(url, timeout=timeout)
  92
  93                 # If the server could not be reached, we will return nothing.
  94                 except DDNSNetworkError:
  95                         return
  96
  97                 if not response.code == 200:
  98                         return
  99
 100                 match = re.search(r"^Your IP address is: (.*)$", response.read())
 101                 if match is None:
 102                         return
 103
 104                 return match.group(1)
 105
 106         def guess_external_ip_address(self, family, **kwargs):
 107                 if family == "ipv6":
 108                         url = "http://checkip6.dns.lightningwirelabs.com"
 109                 elif family == "ipv4":
 110                         url = "http://checkip4.dns.lightningwirelabs.com"
 111                 else:
 112                         raise ValueError("unknown address family")
 113
 114                 return self._guess_external_ip_address(url, **kwargs)
 115
 116         def send_request(self, url, method="GET", data=None, username=None, password=None, timeout=30):
 117                 assert method in ("GET", "POST")
 118
 119                 # Add all arguments in the data dict to the URL and escape them properly.
 120                 if method == "GET" and data:
 121                         query_args = self._format_query_args(data)
 122                         data = None
 123
 124                         if "?" in url:
 125                                 url = "%s&%s" % (url, query_args)
 126                         else:
 127                                 url = "%s?%s" % (url, query_args)
 128
 129                 logger.debug("Sending request (%s): %s" % (method, url))
 130                 if data:
 131                         logger.debug("  data: %s" % data)
 132
 133                 req = urllib2.Request(url, data=data)
 134
 135                 if username and password:
 136                         basic_auth_header = self._make_basic_auth_header(username, password)
 137                         req.add_header("Authorization", "Basic %s" % basic_auth_header)
 138
 139                 # Set the user agent.
 140                 req.add_header("User-Agent", self.USER_AGENT)
 141
 142                 # All requests should not be cached anywhere.
 143                 req.add_header("Pragma", "no-cache")
 144
 145                 # Set the upstream proxy if needed.
 146                 if self.proxy:
 147                         logger.debug("Using proxy: %s" % self.proxy)
 148
 149                         # Configure the proxy for this request.
 150                         req.set_proxy(self.proxy, "http")
 151
 152                 assert req.get_method() == method
 153
 154                 logger.debug(_("Request header:"))
 155                 for k, v in req.headers.items():
 156                         logger.debug("  %s: %s" % (k, v))
 157
 158                 try:
 159                         resp = urllib2.urlopen(req, timeout=timeout)
 160
 161                         # Log response header.
 162                         logger.debug(_("Response header (Status Code %s):") % resp.code)
 163                         for k, v in resp.info().items():
 164                                 logger.debug("  %s: %s" % (k, v))
 165
 166                         # Return the entire response object.
 167                         return resp
 168
 169                 except urllib2.HTTPError, e:
 170                         # 400 - Bad request
 171                         if e.code == 400:
 172                                 raise DDNSRequestError(e.reason)
 173
 174                         # 401 - Authorization Required
 175                         # 403 - Forbidden
 176                         elif e.code in (401, 403):
 177                                 raise DDNSAuthenticationError(e.reason)
 178
 179                         # 500 - Internal Server Error
 180                         elif e.code == 500:
 181                                 raise DDNSInternalServerError(e.reason)
 182
 183                         # 503 - Service Unavailable
 184                         elif e.code == 503:
 185                                 raise DDNSServiceUnavailableError(e.reason)
 186
 187                         # Raise all other unhandled exceptions.
 188                         raise
 189
 190                 except urllib2.URLError, e:
 191                         if e.reason:
 192                                 # Network Unreachable (e.g. no IPv6 access)
 193                                 if e.reason.errno == 101:
 194                                         raise DDNSNetworkUnreachableError
 195                                 elif e.reason.errno == 111:
 196                                         raise DDNSConnectionRefusedError
 197
 198                         # Raise all other unhandled exceptions.
 199                         raise
 200
 201                 except socket.timeout, e:
 202                         logger.debug(_("Connection timeout"))
 203
 204                         raise DDNSConnectionTimeoutError
 205
 206         def _format_query_args(self, data):
 207                 args = []
 208
 209                 for k, v in data.items():
 210                         arg = "%s=%s" % (k, urllib.quote(v))
 211                         args.append(arg)
 212
 213                 return "&".join(args)
 214
 215         def _make_basic_auth_header(self, username, password):
 216                 authstring = "%s:%s" % (username, password)
 217
 218                 # Encode authorization data in base64.
 219                 authstring = base64.encodestring(authstring)
 220
 221                 # Remove any newline characters.
 222                 authstring = authstring.replace("\n", "")
 223
 224                 return authstring
 225
 226         def get_address(self, proto):
 227                 """
 228                         Returns the current IP address for
 229                         the given IP protocol.
 230                 """
 231                 try:
 232                         return self.__addresses[proto]
 233
 234                 # IP is currently unknown and needs to be retrieved.
 235                 except KeyError:
 236                         self.__addresses[proto] = address = \
 237                                 self._get_address(proto)
 238
 239                         return address
 240
 241         def _get_address(self, proto):
 242                 assert proto in ("ipv6", "ipv4")
 243
 244                 # IPFire 2 does not support IPv6.
 245                 if self.distro == "ipfire-2" and proto == "ipv6":
 246                         return
 247
 248                 # Check if the external IP address should be guessed from
 249                 # a remote server.
 250                 guess_ip = self.core.settings.get("guess_external_ip", "true")
 251
 252                 # If the external IP address should be used, we just do
 253                 # that.
 254                 if guess_ip in ("true", "yes", "1"):
 255                         return self.guess_external_ip_address(proto)
 256
 257                 # Get the local IP addresses.
 258                 else:
 259                         if proto == "ipv6":
 260                                 return self.get_local_ipv6_address()
 261                         elif proto == "ipv4":
 262                                 return self.get_local_ipv4_address()
 263
 264         def resolve(self, hostname, proto=None):
 265                 addresses = []
 266
 267                 if proto is None:
 268                         family = 0
 269                 elif proto == "ipv6":
 270                         family = socket.AF_INET6
 271                 elif proto == "ipv4":
 272                         family = socket.AF_INET
 273                 else:
 274                         raise ValueError("Protocol not supported: %s" % proto)
 275
 276                 # Resolve the host address.
 277                 try:
 278                         response = socket.getaddrinfo(hostname, None, family)
 279                 except socket.gaierror, e:
 280                         # Name or service not known
 281                         if e.errno == -2:
 282                                 return []
 283
 284                         # No record for requested family available (e.g. no AAAA)
 285                         elif e.errno == -5:
 286                                 return []
 287
 288                         raise
 289
 290                 # Handle responses.
 291                 for family, socktype, proto, canonname, sockaddr in response:
 292                         # IPv6
 293                         if family == socket.AF_INET6:
 294                                 address, port, flow_info, scope_id = sockaddr
 295
 296                                 # Only use the global scope.
 297                                 if not scope_id == 0:
 298                                         continue
 299
 300                         # IPv4
 301                         elif family == socket.AF_INET:
 302                                 address, port = sockaddr
 303
 304                         # Ignore everything else...
 305                         else:
 306                                 continue
 307
 308                         # Add to repsonse list if not already in there.
 309                         if not address in addresses:
 310                                 addresses.append(address)
 311
 312                 return addresses
 313
 314         def _get_distro_identifier(self):
 315                 """
 316                         Returns a unique identifier for the distribution
 317                         we are running on.
 318                 """
 319                 os_release = self.__parse_os_release()
 320                 if os_release:
 321                         return os_release
 322
 323                 system_release = self.__parse_system_release()
 324                 if system_release:
 325                         return system_release
 326
 327                 # If nothing else could be found, we return
 328                 # just "unknown".
 329                 return "unknown"
 330
 331         def __parse_os_release(self):
 332                 """
 333                         Tries to parse /etc/os-release and
 334                         returns a unique distribution identifier
 335                         if the file exists.
 336                 """
 337                 try:
 338                         f = open("/etc/os-release", "r")
 339                 except IOError, e:
 340                         # File not found
 341                         if e.errno == 2:
 342                                 return
 343
 344                         raise
 345
 346                 os_release = {}
 347                 with f:
 348                         for line in f.readlines():
 349                                 m = re.match(r"^([A-Z\_]+)=(.*)$", line)
 350                                 if m is None:
 351                                         continue
 352
 353                                 os_release[m.group(1)] = m.group(2)
 354
 355                 try:
 356                         return "%(ID)s-%(VERSION_ID)s" % os_release
 357                 except KeyError:
 358                         return
 359
 360         def __parse_system_release(self):
 361                 """
 362                         Tries to parse /etc/system-release and
 363                         returns a unique distribution identifier
 364                         if the file exists.
 365                 """
 366                 try:
 367                         f = open("/etc/system-release", "r")
 368                 except IOError, e:
 369                         # File not found
 370                         if e.errno == 2:
 371                                 return
 372
 373                         raise
 374
 375                 with f:
 376                         # Read first line
 377                         line = f.readline()
 378
 379                         # Check for IPFire systems
 380                         m = re.match(r"^IPFire (\d).(\d+)", line)
 381                         if m:
 382                                 return "ipfire-%s" % m.group(1)