From 4bba8e4cb44ca5b357cbcf895c06a9ea4b4677f5 Mon Sep 17 00:00:00 2001
From: Apollon Oikonomopoulos <apollon@noc.grnet.gr>
Date: Mon, 18 Apr 2011 16:37:37 +0300
Subject: [PATCH] Add ganeti.network: address pool management tools
lib.network contains AddressPool, a helper class for ganeti.objects.Network.
AddressPool wraps a Network object and provides all IPv4 Address Pool
management logic, manipulating the respective fields of the Network object.
Signed-off-by: Apollon Oikonomopoulos <apollon@noc.grnet.gr>
---
Makefile.am | 2 +-
lib/errors.py | 6 ++
lib/network.py | 179 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 186 insertions(+), 1 deletion(-)
create mode 100644 lib/network.py
diff --git a/Makefile.am b/Makefile.am
index 91ab8a47d..865df3ebe 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -160,7 +160,7 @@ pkgpython_PYTHON = \
lib/ssh.py \
lib/storage.py \
lib/uidpool.py \
- lib/ippool.py \
+ lib/network.py \
lib/workerpool.py
client_PYTHON = \
diff --git a/lib/errors.py b/lib/errors.py
index 9f609d2f5..e4497bca3 100644
--- a/lib/errors.py
+++ b/lib/errors.py
@@ -120,6 +120,12 @@ class ConfigVersionMismatch(ConfigurationError):
pass
+class AddressPoolError(GenericError):
+ """Errors related to IP address pools.
+
+ """
+
+
class ReservationError(GenericError):
"""Errors reserving a resource.
diff --git a/lib/network.py b/lib/network.py
new file mode 100644
index 000000000..062bcb60d
--- /dev/null
+++ b/lib/network.py
@@ -0,0 +1,179 @@
+#
+#
+
+# Copyright (C) 2011 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 ganeti import errors
+
+from base64 import b64encode
+from base64 import b64decode
+
+from bitarray import bitarray
+
+
+class AddressPool(object):
+ """Address pool class, wrapping an objects.Network object
+
+ This class provides methods to manipulate address pools, backed by
+ L{objects.Network} objects.
+
+ """
+ def __init__(self, network):
+ """Initialize a new IPv4 address pool from an objects.Network object
+
+ @type network: L{objects.Network}
+ @param network: the network object from which the pool will be generated
+
+ """
+ self.net = network
+ self.network = ipaddr.IPNetwork(self.net.network)
+ if self.net.gateway:
+ self.gateway = ipaddr.IPAddress(self.net.gateway)
+ else:
+ self.gateway = None
+
+ if self.net.reservations:
+ self.reservations = bitarray()
+ self.reservations.fromstring(b64decode(self.net.reservations))
+ else:
+ self.reservations = bitarray(self.network.numhosts)
+ self.reservations.setall(False)
+
+ if self.net.ext_reservations:
+ self.ext_reservations = bitarray()
+ self.ext_reservations.fromstring(b64decode(self.net.ext_reservations))
+ else:
+ self.ext_reservations = bitarray(self.network.numhosts)
+ self.ext_reservations.setall(False)
+
+ assert len(self.reservations) == self.network.numhosts
+ assert len(self.ext_reservations) == self.network.numhosts
+
+ def _GetAddrIndex(self, address):
+ addr = ipaddr.IPAddress(address)
+
+ if not addr in self.network:
+ raise errors.AddressPoolError("%s does not contain %s" %
+ (self.network, addr))
+
+ return int(addr) - int(self.network.network)
+
+ def _Update(self):
+ """Write address pools back to the network object"""
+ self.net.ext_reservations = b64encode(self.ext_reservations.tostring())
+ self.net.reservations = b64encode(self.reservations.tostring())
+
+ 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 + external reservations."""
+ return (self.reservations | self.ext_reservations)
+
+ def Validate(self):
+ assert self.net.family == 4
+ assert len(self.reservations) == self._GetSize()
+ assert len(self.ext_reservations) == self._GetSize()
+ assert not (self.reservations & self.ext_reservations).any()
+
+ if self.gateway is not None:
+ assert self.net.family == self.gateway.version
+ assert self.gateway in self.network
+
+ return True
+
+ def IsFull(self):
+ """Check whether the network is full"""
+ return self.all_reservations.all()
+
+ 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 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.AddressPoolError("%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.IsFull():
+ raise errors.AddressPoolError("%s is full" % self.network)
+
+ idx = self.all_reservations.index(False)
+ address = str(self.network[idx])
+ self.Reserve(address)
+ return address
+
+ def GenerateFree(self):
+ """A generator for free addresses."""
+ def _iter_free():
+ for idx in self.all_reservations.search("0", 64):
+ yield str(self.network[idx])
+
+ return _iter_free().next
+
+ @classmethod
+ def InitializeNetwork(cls, net):
+ """Initialize an L{objects.Network} object
+
+ Reserve the network, broadcast and gateway IPs
+
+ """
+ obj = cls(net)
+ obj._Update()
+ for ip in [obj.network[0], obj.network[-1]]:
+ obj.Reserve(ip, external=True)
+ if obj.net.gateway is not None:
+ obj.Reserve(obj.net.gateway, external=True)
+ obj.Validate()
+ return obj
--
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