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                         # 503 - Service Unavailable
 172                         if e.code == 503:
 173                                 raise DDNSServiceUnavailableError
 174
 175                         # Raise all other unhandled exceptions.
 176                         raise
 177
 178                 except urllib2.URLError, e:
 179                         if e.reason:
 180                                 # Network Unreachable (e.g. no IPv6 access)
 181                                 if e.reason.errno == 101:
 182                                         raise DDNSNetworkUnreachableError
 183                                 elif e.reason.errno == 111:
 184                                         raise DDNSConnectionRefusedError
 185
 186                         # Raise all other unhandled exceptions.
 187                         raise
 188
 189                 except socket.timeout, e:
 190                         logger.debug(_("Connection timeout"))
 191
 192                         raise DDNSConnectionTimeoutError
 193
 194         def _format_query_args(self, data):
 195                 args = []
 196
 197                 for k, v in data.items():
 198                         arg = "%s=%s" % (k, urllib.quote(v))
 199                         args.append(arg)
 200
 201                 return "&".join(args)
 202
 203         def _make_basic_auth_header(self, username, password):
 204                 authstring = "%s:%s" % (username, password)
 205
 206                 # Encode authorization data in base64.
 207                 authstring = base64.encodestring(authstring)
 208
 209                 # Remove any newline characters.
 210                 authstring = authstring.replace("\n", "")
 211
 212                 return authstring
 213
 214         def get_address(self, proto):
 215                 assert proto in ("ipv6", "ipv4")
 216
 217                 # IPFire 2 does not support IPv6.
 218                 if self.distro == "ipfire-2" and proto == "ipv6":
 219                         return
 220
 221                 # Check if the external IP address should be guessed from
 222                 # a remote server.
 223                 guess_ip = self.core.settings.get("guess_external_ip", "true")
 224
 225                 # If the external IP address should be used, we just do
 226                 # that.
 227                 if guess_ip in ("true", "yes", "1"):
 228                         if proto == "ipv6":
 229                                 return self.guess_external_ipv6_address()
 230
 231                         elif proto == "ipv4":
 232                                 return self.guess_external_ipv4_address()
 233
 234                 # Get the local IP addresses.
 235                 else:
 236                         if proto == "ipv6":
 237                                 return self.get_local_ipv6_address()
 238                         elif proto == "ipv4":
 239                                 return self.get_local_ipv4_address()
 240
 241         def resolve(self, hostname, proto=None):
 242                 addresses = []
 243
 244                 if proto is None:
 245                         family = 0
 246                 elif proto == "ipv6":
 247                         family = socket.AF_INET6
 248                 elif proto == "ipv4":
 249                         family = socket.AF_INET
 250                 else:
 251                         raise ValueError("Protocol not supported: %s" % proto)
 252
 253                 # Resolve the host address.
 254                 try:
 255                         response = socket.getaddrinfo(hostname, None, family)
 256                 except socket.gaierror, e:
 257                         # Name or service not known
 258                         if e.errno == -2:
 259                                 return []
 260
 261                         # No record for requested family available (e.g. no AAAA)
 262                         elif e.errno == -5:
 263                                 return []
 264
 265                         raise
 266
 267                 # Handle responses.
 268                 for family, socktype, proto, canonname, sockaddr in response:
 269                         # IPv6
 270                         if family == socket.AF_INET6:
 271                                 address, port, flow_info, scope_id = sockaddr
 272
 273                                 # Only use the global scope.
 274                                 if not scope_id == 0:
 275                                         continue
 276
 277                         # IPv4
 278                         elif family == socket.AF_INET:
 279                                 address, port = sockaddr
 280
 281                         # Ignore everything else...
 282                         else:
 283                                 continue
 284
 285                         # Add to repsonse list if not already in there.
 286                         if not address in addresses:
 287                                 addresses.append(address)
 288
 289                 return addresses
 290
 291         def _get_distro_identifier(self):
 292                 """
 293                         Returns a unique identifier for the distribution
 294                         we are running on.
 295                 """
 296                 os_release = self.__parse_os_release()
 297                 if os_release:
 298                         return os_release
 299
 300                 system_release = self.__parse_system_release()
 301                 if system_release:
 302                         return system_release
 303
 304                 # If nothing else could be found, we return
 305                 # just "unknown".
 306                 return "unknown"
 307
 308         def __parse_os_release(self):
 309                 """
 310                         Tries to parse /etc/os-release and
 311                         returns a unique distribution identifier
 312                         if the file exists.
 313                 """
 314                 try:
 315                         f = open("/etc/os-release", "r")
 316                 except IOError, e:
 317                         # File not found
 318                         if e.errno == 2:
 319                                 return
 320
 321                         raise
 322
 323                 os_release = {}
 324                 with f:
 325                         for line in f.readlines():
 326                                 m = re.match(r"^([A-Z\_]+)=(.*)$", line)
 327                                 if m is None:
 328                                         continue
 329
 330                                 os_release[m.group(1)] = m.group(2)
 331
 332                 try:
 333                         return "%(ID)s-%(VERSION_ID)s" % os_release
 334                 except KeyError:
 335                         return
 336
 337         def __parse_system_release(self):
 338                 """
 339                         Tries to parse /etc/system-release and
 340                         returns a unique distribution identifier
 341                         if the file exists.
 342                 """
 343                 try:
 344                         f = open("/etc/system-release", "r")
 345                 except IOError, e:
 346                         # File not found
 347                         if e.errno == 2:
 348                                 return
 349
 350                         raise
 351
 352                 with f:
 353                         # Read first line
 354                         line = f.readline()
 355
 356                         # Check for IPFire systems
 357                         m = re.match(r"^IPFire (\d).(\d+)", line)
 358                         if m:
 359                                 return "ipfire-%s" % m.group(1)