/lib/network.py - snf-ganeti - Greek Research and Technology Network's projects

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+      #
+      #
       # Copyright (C) 2011, 2012 Google Inc.
+      #
       # This program is free software; you can redistribute it and/or modify
       # it under the terms of the GNU General Public License as published by
       # the Free Software Foundation; either version 2 of the License, or
       # (at your option) any later version.
+      #
       # This program is distributed in the hope that it will be useful, but
       # WITHOUT ANY WARRANTY; without even the implied warranty of
       # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
       # General Public License for more details.
+      #
       # You should have received a copy of the GNU General Public License
       # along with this program; if not, write to the Free Software
       # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
       # 02110-1301, USA.
       """IP address pool management functions.
       """
       import ipaddr
       from bitarray import bitarray
       from ganeti import errors
       from ganeti import utils
       from ganeti import constants
       import logging
       def _ComputeIpv4NumHosts(network_size):
         """Derives the number of hosts in an IPv4 network from the size.
         """
         return 2 ** (32 - network_size)
       IPV4_NETWORK_MIN_SIZE = 30
       # FIXME: This limit is for performance reasons. Remove when refactoring
       # for performance tuning was successful.
       IPV4_NETWORK_MAX_SIZE = 16
       IPV4_NETWORK_MIN_NUM_HOSTS = _ComputeIpv4NumHosts(IPV4_NETWORK_MIN_SIZE)
       IPV4_NETWORK_MAX_NUM_HOSTS = _ComputeIpv4NumHosts(IPV4_NETWORK_MAX_SIZE)
       class Network(object):
         """ Wrapper Class for networks.
         Used to get a network out of a L{objects.Network}. In case nobj
         has an IPv4 subnet it returns an AddressPool object. Otherwise
         a GenericNetwork object is created. To get a network use:
         network.Network(nobj)
         """
         def __new__(cls, nobj):
           if nobj.network:
             return AddressPool(nobj)
           else:
             return GenericNetwork(nobj)
         @classmethod
         def Check(cls, address, network):
           try:
             if network:
               network = ipaddr.IPNetwork(network)
             if address:
               address = ipaddr.IPAddress(address)
           except ValueError, e:
             raise errors.OpPrereqError(e, errors.ECODE_INVAL)
           if address and not network:
             raise errors.OpPrereqError("Address '%s' but no network." % address,
                                        errors.ECODE_INVAL)
           if address and address not in network:
             raise errors.OpPrereqError("Address '%s' not in network '%s'." %
                                        (address, network),
                                        errors.ECODE_INVAL)
         def Contains(self, address):
           pass
         def IsReserved(self, address):
           pass
         def Reserve(self, address, external):
           pass
         def Release(self, address, external):
           pass
         def GenerateFree(self):
           pass
         def GetStats(self):
           pass
       class GenericNetwork(object):
         """ Base class for networks.
         This includes all info and methods deriving from subnets and gateways
         both IPv4 and IPv6. Implements basic checks and abstracts the methods
         that are invoked by external methods.
         """
         def __init__(self, nobj):
           """Initializes a Generic Network from an L{objects.Network} object.
           @type nobj: L{objects.Network}
           @param nobj: the network object
           """
           self.network = None
           self.gateway = None
           self.network6 = None
           self.gateway6 = None
           self.nobj = nobj
           if self.nobj.gateway and not self.nobj.network:
             raise errors.OpPrereqError("Gateway without network. Cannot proceed")
           if self.nobj.network:
             self.network = ipaddr.IPNetwork(self.nobj.network)
             if self.nobj.gateway:
               self.gateway = ipaddr.IPAddress(self.nobj.gateway)
               if self.gateway not in self.network:
                 raise errors.OpPrereqError("Gateway not in network.",
                                            errors.ECODE_INVAL)
           if self.nobj.gateway6 and not self.nobj.network6:
             raise errors.OpPrereqError("IPv6 Gateway without IPv6 network."
                                        " Cannot proceed.",
                                        errors.ECODE_INVAL)
           if self.nobj.network6:
             self.network6 = ipaddr.IPv6Network(self.nobj.network6)
             if self.nobj.gateway6:
               self.gateway6 = ipaddr.IPv6Address(self.nobj.gateway6)
               if self.gateway6 not in self.network6:
                 raise errors.OpPrereqError("IPv6 Gateway not in IPv6 network.",
                                            errors.ECODE_INVAL)
         def _Validate(self):
           if self.gateway:
             assert self.network
             assert self.gateway in self.network
           if self.gateway6:
             assert self.network6
             assert self.gateway6 in self.network6
         def Contains(self, address):
           if address:
             addr = ipaddr.IPAddress(address)
             if addr.version == constants.IP4_VERSION and self.network:
               return addr in self.network
             elif addr.version == constants.IP6_VERSION and self.network6:
               return addr in self.network6
           return False
         def IsReserved(self, address):
           logging.info("Check if %s is reserved in network %s",
                        address, self.nobj.name)
           return False
         def Reserve(self, address, external):
           pass
         def Release(self, address, external):
           pass
         def GenerateFree(self):
           raise errors.OpPrereqError("Cannot generate IP in a Generic Network",
                                      errors.ECODE_INVAL)
         def GetStats(self):
           return {}
       class AddressPool(GenericNetwork):
         """Address pool class, wrapping an C{objects.Network} object.
         This class provides methods to manipulate address pools, backed by
         L{objects.Network} objects.
         """
         FREE = bitarray("0")
         RESERVED = bitarray("1")
         def __init__(self, nobj):
           """Initialize a new IPv4 address pool from an L{objects.Network} object.
           @type network: L{objects.Network}
           @param network: the network object from which the pool will be generated
           """
           super(AddressPool, self).__init__(nobj)
           if self.nobj.reservations and self.nobj.ext_reservations:
             self.reservations = bitarray(self.nobj.reservations)
             self.ext_reservations = bitarray(self.nobj.ext_reservations)
           else:
             self._InitializeReservations()
           self._Validate()
         def _InitializeReservations(self):
           self.reservations = bitarray(self.network.numhosts)
           self.reservations.setall(False) # pylint: disable=E1103
           self.ext_reservations = bitarray(self.network.numhosts)
           self.ext_reservations.setall(False) # pylint: disable=E1103
           for ip in [self.network[0], self.network[-1]]:
             self.Reserve(ip, external=True)
           if self.nobj.gateway:
             self.Reserve(self.nobj.gateway, external=True)
           self._Update()
         def _GetAddrIndex(self, address):
           addr = ipaddr.IPAddress(address)
           assert addr in self.network
           return int(addr) - int(self.network.network)
         def _Update(self):
           """Write address pools back to the network object.
           """
           # pylint: disable=E1103
           self.nobj.ext_reservations = self.ext_reservations.to01()
           self.nobj.reservations = self.reservations.to01()
         def _Mark(self, address, value=True, external=False):
           idx = self._GetAddrIndex(address)
           if external:
             self.ext_reservations[idx] = value
           else:
             self.reservations[idx] = value
           self._Update()
         def _GetSize(self):
           return 2 ** (32 - self.network.prefixlen)
         @property
         def _all_reservations(self):
           """Return a combined map of internal and external reservations.
           """
           return (self.reservations | self.ext_reservations)
         def _Validate(self):
           super(AddressPool, self)._Validate()
           assert len(self.reservations) == self.network.numhosts
           assert len(self.ext_reservations) == self.network.numhosts
           all_res = self.reservations & self.ext_reservations
           assert not all_res.any()
         def _GetReservedCount(self):
           """Get the count of reserved addresses.
           """
           return self._all_reservations.count(True)
         def _GetFreeCount(self):
           """Get the count of unused addresses.
           """
           return self._all_reservations.count(False)
         def _GetMap(self):
           """Return a textual representation of the network's occupation status.
           """
           return self._all_reservations.to01().replace("1", "X").replace("0", ".")
         def _GetExternalReservations(self):
           """Returns a list of all externally reserved addresses.
           """
           # pylint: disable=E1103
           idxs = self.ext_reservations.search(self.RESERVED)
           return [str(self.network[idx]) for idx in idxs]
         def IsReserved(self, address):
           """Checks if the given IP is reserved.
           """
           idx = self._GetAddrIndex(address)
           return self._all_reservations[idx]
         def Reserve(self, address, external=False):
           """Mark an address as used.
           """
           if self.IsReserved(address):
             raise errors.NetworkError("%s is already reserved" % address)
           self._Mark(address, external=external)
         def Release(self, address, external=False):
           """Release a given address reservation.
           """
           self._Mark(address, value=False, external=external)
         def GetFreeAddress(self):
           """Returns the first available address.
           """
           if self._all_reservations.all():
             raise errors.NetworkError("%s is full" % self.network)
           idx = self._all_reservations.index(False)
           address = str(self.network[idx])
           self.Reserve(address)
           return address
         def GenerateFree(self):
           """Returns the first free address of the network.
           @raise errors.NetworkError: Pool is full
           """
           idx = self._all_reservations.search(self.FREE, 1)
           if not idx:
             raise errors.NetworkError("%s is full" % self.network)
           return str(self.network[idx[0]])
         def GetStats(self):
           """Returns statistics for a network address pool.
           """
           return {
             "free_count": self._GetFreeCount(),
             "reserved_count": self._GetReservedCount(),
             "map": self._GetMap(),
             "external_reservations":
               utils.CommaJoin(self._GetExternalReservations()),
+            }

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root / lib / network.py @ 7aea0198