root / lib / network.py @ 5e1c599f
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# Copyright (C) 2011, 2012 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""IP address pool management functions.
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"""
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import ipaddr |
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from bitarray import bitarray |
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from ganeti import errors |
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from ganeti import utils |
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from ganeti import constants |
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def _ComputeIpv4NumHosts(network_size): |
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"""Derives the number of hosts in an IPv4 network from the size.
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"""
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return 2 ** (32 - network_size) |
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IPV4_NETWORK_MIN_SIZE = 30
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# FIXME: This limit is for performance reasons. Remove when refactoring
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# for performance tuning was successful.
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IPV4_NETWORK_MAX_SIZE = 16
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IPV4_NETWORK_MIN_NUM_HOSTS = _ComputeIpv4NumHosts(IPV4_NETWORK_MIN_SIZE) |
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IPV4_NETWORK_MAX_NUM_HOSTS = _ComputeIpv4NumHosts(IPV4_NETWORK_MAX_SIZE) |
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class Network(object): |
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""" Wrapper Class for networks.
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Used to get a network out of a L{objects.Network}. In case nobj
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has an IPv4 subnet it returns an AddressPool object. Otherwise
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a GenericNetwork object is created. To get a network use:
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network.Network(nobj)
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"""
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def __new__(cls, nobj): |
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if nobj.network:
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return AddressPool(nobj)
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else:
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return GenericNetwork(nobj)
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@classmethod
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def Check(cls, address, network): |
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try:
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if network:
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network = ipaddr.IPNetwork(network) |
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if address:
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address = ipaddr.IPAddress(address) |
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except ValueError, e: |
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raise errors.OpPrereqError(e, errors.ECODE_INVAL)
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if address and not network: |
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raise errors.OpPrereqError("Address '%s' but no network." % address, |
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errors.ECODE_INVAL) |
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if address and address not in network: |
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raise errors.OpPrereqError("Address '%s' not in network '%s'." % |
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(address, network), |
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errors.ECODE_INVAL) |
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class GenericNetwork(object): |
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""" Base class for networks.
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This includes all info and methods deriving from subnets and gateways
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both IPv4 and IPv6. Implements basic checks and abstracts the methods
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that are invoked by external methods.
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"""
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def __init__(self, nobj): |
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"""Initializes a Generic Network from an L{objects.Network} object.
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@type nobj: L{objects.Network}
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@param nobj: the network object
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"""
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self.network = None |
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self.gateway = None |
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self.network6 = None |
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self.gateway6 = None |
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self.nobj = nobj
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if self.nobj.gateway and not self.nobj.network: |
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raise errors.OpPrereqError("Gateway without network. Cannot proceed") |
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if self.nobj.network: |
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self.network = ipaddr.IPNetwork(self.nobj.network) |
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if self.nobj.gateway: |
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self.gateway = ipaddr.IPAddress(self.nobj.gateway) |
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if self.gateway not in self.network: |
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raise errors.OpPrereqError("Gateway not in network.", |
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errors.ECODE_INVAL) |
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if self.nobj.gateway6 and not self.nobj.network6: |
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raise errors.OpPrereqError("IPv6 Gateway without IPv6 network." |
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" Cannot proceed.",
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errors.ECODE_INVAL) |
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if self.nobj.network6: |
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self.network6 = ipaddr.IPv6Network(self.nobj.network6) |
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if self.nobj.gateway6: |
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self.gateway6 = ipaddr.IPv6Address(self.nobj.gateway6) |
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if self.gateway6 not in self.network6: |
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raise errors.OpPrereqError("IPv6 Gateway not in IPv6 network.", |
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errors.ECODE_INVAL) |
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def _Validate(self): |
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if self.gateway: |
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assert self.network |
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assert self.gateway in self.network |
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if self.gateway6: |
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assert self.network6 |
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assert self.gateway6 in self.network6 |
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def Contains(self, address): |
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if address:
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addr = ipaddr.IPAddress(address) |
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if addr.version == constants.IP4_VERSION and self.network: |
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return addr in self.network |
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elif addr.version == constants.IP6_VERSION and self.network6: |
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return addr in self.network6 |
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return False |
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def IsReserved(self, address): |
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return False |
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def Reserve(self, address, external): |
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pass
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def Release(self, address, external): |
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pass
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def GenerateFree(self): |
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raise errors.OpPrereqError("Cannot generate IP in a Generic Network", |
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errors.ECODE_INVAL) |
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def GetStats(self): |
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return {}
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class AddressPool(GenericNetwork): |
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"""Address pool class, wrapping an C{objects.Network} object.
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This class provides methods to manipulate address pools, backed by
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L{objects.Network} objects.
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"""
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FREE = bitarray("0")
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RESERVED = bitarray("1")
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def __init__(self, nobj): |
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"""Initialize a new IPv4 address pool from an L{objects.Network} object.
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@type network: L{objects.Network}
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@param network: the network object from which the pool will be generated
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"""
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super(AddressPool, self).__init__(nobj) |
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if self.nobj.reservations and self.nobj.ext_reservations: |
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self.reservations = bitarray(self.nobj.reservations) |
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self.ext_reservations = bitarray(self.nobj.ext_reservations) |
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else:
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self._InitializeReservations()
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self._Validate()
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def _InitializeReservations(self): |
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self.reservations = bitarray(self.network.numhosts) |
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self.reservations.setall(False) # pylint: disable=E1103 |
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self.ext_reservations = bitarray(self.network.numhosts) |
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self.ext_reservations.setall(False) # pylint: disable=E1103 |
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for ip in [self.network[0], self.network[-1]]: |
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self.Reserve(ip, external=True) |
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if self.nobj.gateway: |
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self.Reserve(self.nobj.gateway, external=True) |
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self._Update()
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def _GetAddrIndex(self, address): |
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addr = ipaddr.IPAddress(address) |
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assert addr in self.network |
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return int(addr) - int(self.network.network) |
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def _Update(self): |
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"""Write address pools back to the network object.
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"""
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# pylint: disable=E1103
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self.net.ext_reservations = self.ext_reservations.to01() |
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self.net.reservations = self.reservations.to01() |
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def _Mark(self, address, value=True, external=False): |
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idx = self._GetAddrIndex(address)
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if external:
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self.ext_reservations[idx] = value
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else:
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self.reservations[idx] = value
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self._Update()
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def _GetSize(self): |
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return 2 ** (32 - self.network.prefixlen) |
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@property
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def _all_reservations(self): |
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"""Return a combined map of internal and external reservations.
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"""
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return (self.reservations | self.ext_reservations) |
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def _Validate(self): |
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super(AddressPool, self)._Validate() |
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assert len(self.reservations) == self.network.numhosts |
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assert len(self.ext_reservations) == self.network.numhosts |
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all_res = self.reservations & self.ext_reservations |
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assert not all_res.any() |
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def _GetReservedCount(self): |
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"""Get the count of reserved addresses.
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"""
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return self._all_reservations.count(True) |
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def _GetFreeCount(self): |
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"""Get the count of unused addresses.
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"""
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return self._all_reservations.count(False) |
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def _GetMap(self): |
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"""Return a textual representation of the network's occupation status.
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"""
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return self._all_reservations.to01().replace("1", "X").replace("0", ".") |
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def _GetExternalReservations(self): |
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"""Returns a list of all externally reserved addresses.
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"""
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# pylint: disable=E1103
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idxs = self.ext_reservations.search(self.RESERVED) |
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return [str(self.network[idx]) for idx in idxs] |
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def IsReserved(self, address): |
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"""Checks if the given IP is reserved.
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"""
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idx = self._GetAddrIndex(address)
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return self._all_reservations[idx] |
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def Reserve(self, address, external=False): |
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"""Mark an address as used.
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"""
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if self.IsReserved(address): |
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raise errors.AddressPoolError("%s is already reserved" % address) |
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self._Mark(address, external=external)
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def Release(self, address, external=False): |
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"""Release a given address reservation.
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"""
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self._Mark(address, value=False, external=external) |
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def GetFreeAddress(self): |
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"""Returns the first available address.
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"""
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if self.IsFull(): |
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raise errors.AddressPoolError("%s is full" % self.network) |
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idx = self.all_reservations.index(False) |
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address = str(self.network[idx]) |
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self.Reserve(address)
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return address
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def GenerateFree(self): |
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"""Returns the first free address of the network.
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@raise errors.AddressPoolError: Pool is full
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"""
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idx = self._all_reservations.search(self.FREE, 1) |
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if not idx: |
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raise errors.NetworkError("%s is full" % self.network) |
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return str(self.network[idx[0]]) |
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def GetStats(self): |
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"""Returns statistics for a network address pool.
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"""
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return {
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"free_count": self._GetFreeCount(), |
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"reserved_count": self._GetReservedCount(), |
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"map": self._GetMap(), |
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"external_reservations":
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utils.CommaJoin(self._GetExternalReservations()),
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} |