code.grnet.gr Git - ganeti-local/blob - lib/network.py

   1 #
   2 #
   3
   4 # Copyright (C) 2011 Google Inc.
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful, but
  12 # WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 # General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, write to the Free Software
  18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 # 02110-1301, USA.
  20
  21
  22 """Ip address pool management functions.
  23
  24 """
  25
  26 import ipaddr
  27
  28 from bitarray import bitarray
  29
  30 from ganeti import errors
  31
  32 class AddressPool(object):
  33   """Address pool class, wrapping an objects.Network object
  34
  35   This class provides methods to manipulate address pools, backed by
  36   L{objects.Network} objects.
  37
  38   """
  39   def __init__(self, network):
  40     """Initialize a new IPv4 address pool from an objects.Network object
  41
  42     @type network: L{objects.Network}
  43     @param network: the network object from which the pool will be generated
  44
  45     """
  46     self.network = None
  47     self.gateway = None
  48     self.network6 = None
  49     self.gateway6 = None
  50
  51     self.net = network
  52
  53     self.network = ipaddr.IPNetwork(self.net.network)
  54     if self.net.gateway:
  55       self.gateway = ipaddr.IPAddress(self.net.gateway)
  56
  57     if self.net.network6:
  58       self.network6 = ipaddr.IPv6Network(self.net.network6)
  59     if self.net.gateway6:
  60       self.gateway6 = ipaddr.IPv6Address(self.net.gateway6)
  61
  62     if self.net.reservations:
  63       self.reservations = bitarray(self.net.reservations)
  64     else:
  65       self.reservations = bitarray(self.network.numhosts)
  66       self.reservations.setall(False)
  67
  68     if self.net.ext_reservations:
  69       self.ext_reservations = bitarray(self.net.ext_reservations)
  70     else:
  71       self.ext_reservations = bitarray(self.network.numhosts)
  72       self.ext_reservations.setall(False)
  73
  74     assert len(self.reservations) == self.network.numhosts
  75     assert len(self.ext_reservations) == self.network.numhosts
  76
  77   def _Contains(self, address):
  78     if address is None:
  79       return False
  80     addr = ipaddr.IPAddress(address)
  81
  82     return addr in self.network
  83
  84   def _GetAddrIndex(self, address):
  85     addr = ipaddr.IPAddress(address)
  86
  87     if not addr in self.network:
  88       raise errors.AddressPoolError("%s does not contain %s" %
  89                                     (self.network, addr))
  90
  91     return int(addr) - int(self.network.network)
  92
  93   def _Update(self):
  94     """Write address pools back to the network object"""
  95     self.net.ext_reservations = self.ext_reservations.to01()
  96     self.net.reservations = self.reservations.to01()
  97
  98   def _Mark(self, address, value=True, external=False):
  99     idx = self._GetAddrIndex(address)
 100     if external:
 101       self.ext_reservations[idx] = value
 102     else:
 103       self.reservations[idx] = value
 104     self._Update()
 105
 106   def _GetSize(self):
 107     return 2**(32 - self.network.prefixlen)
 108
 109   @property
 110   def all_reservations(self):
 111     """Return a combined map of internal + external reservations."""
 112     return (self.reservations | self.ext_reservations)
 113
 114   def Validate(self):
 115     assert self.net.family == 4
 116     assert len(self.reservations) == self._GetSize()
 117     assert len(self.ext_reservations) == self._GetSize()
 118     assert not (self.reservations & self.ext_reservations).any()
 119
 120     if self.gateway is not None:
 121       assert self.net.family == self.gateway.version
 122       assert self.gateway in self.network
 123
 124     if self.network6 and self.gateway6:
 125       assert self.gateway6 in self.network6
 126
 127     return True
 128
 129   def IsFull(self):
 130     """Check whether the network is full"""
 131     return self.all_reservations.all()
 132
 133   def GetReservedCount(self):
 134     """Get the count of reserved addresses"""
 135     return self.all_reservations.count(True)
 136
 137   def GetFreeCount(self):
 138     """Get the count of unused addresses"""
 139     return self.all_reservations.count(False)
 140
 141   def GetMap(self):
 142     """Return a textual representation of the network's occupation status."""
 143     return self.all_reservations.to01().replace("1", "X").replace("0", ".")
 144
 145   def IsReserved(self, address):
 146     """Checks if the given IP is reserved"""
 147     idx = self._GetAddrIndex(address)
 148     return self.all_reservations[idx]
 149
 150   def Reserve(self, address, external=False):
 151     """Mark an address as used."""
 152     if self.IsReserved(address):
 153       raise errors.AddressPoolError("%s is already reserved" % address)
 154     self._Mark(address, external=external)
 155
 156   def Release(self, address, external=False):
 157     """Release a given address reservation."""
 158     self._Mark(address, value=False, external=external)
 159
 160   def GetFreeAddress(self):
 161     """Returns the first available address."""
 162     if self.IsFull():
 163       raise errors.AddressPoolError("%s is full" % self.network)
 164
 165     idx = self.all_reservations.index(False)
 166     address = str(self.network[idx])
 167     self.Reserve(address)
 168     return address
 169
 170   def GenerateFree(self):
 171     """A generator for free addresses."""
 172     def _iter_free():
 173       for idx in self.all_reservations.search("0", 64):
 174         yield str(self.network[idx])
 175
 176     return _iter_free().next
 177
 178   def GetExternalReservations(self):
 179     """Returns a list of all externally reserved addresses"""
 180     idxs = self.ext_reservations.search("1")
 181     return [str(self.network[idx]) for idx in idxs]
 182
 183   @classmethod
 184   def InitializeNetwork(cls, net):
 185     """Initialize an L{objects.Network} object
 186
 187     Reserve the network, broadcast and gateway IPs
 188
 189     """
 190     obj = cls(net)
 191     obj._Update()
 192     for ip in [obj.network[0], obj.network[-1]]:
 193       obj.Reserve(ip, external=True)
 194     if obj.net.gateway is not None:
 195       obj.Reserve(obj.net.gateway, external=True)
 196     obj.Validate()
 197     return obj