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