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gns3-server/gns3server/compute/qemu/utils/guest_cid.py

39 lines
1.2 KiB

# -*- coding: utf-8 -*-
#
# Copyright (C) 2017 GNS3 Technologies 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 3 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, see <http://www.gnu.org/licenses/>.
from ..qemu_error import QemuError
import logging
log = logging.getLogger(__name__)
def get_next_guest_cid(nodes):
"""
Calculates free guest_id from given nodes
:param nodes:
:raises QemuError when exceeds number
:return: integer first free cid
"""
used = set([n.guest_cid for n in nodes])
pool = set(range(3, 65535))
try:
return (pool - used).pop()
except KeyError:
raise QemuError("Cannot create a new Qemu VM (limit of 65535 guest ID on one host reached)")