uncloud/uncloud_net/selectors.py

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from django.db import transaction
from django.db.models import Count, F
from .models import *
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def get_suitable_pool(subnetwork_mask):
"""
Find suitable pools for a certain network size.
First, filter for all pools that offer the requested subnetwork_size.
Then find those pools that are not fully exhausted:
The number of available networks in a pool is 2^(subnetwork_size-network_size.
The number of available networks in a pool is given by the number of VPNNetworkreservations.
"""
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return WireGuardVPNPool.objects.annotate(
num_reservations=Count('wireguardvpn'),
max_reservations=2**(F('subnetwork_mask')-F('network_mask'))).filter(
num_reservations__lt=F('max_reservations'),
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subnetwork_mask=subnetwork_mask)
def allowed_vpn_network_reservation_size():
"""
Find all possible sizes of subnetworks that are available.
Select all pools with free networks.
Get their subnetwork sizes, reduce to a set
"""
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pools = WireGuardVPNPool.objects.annotate(num_reservations=Count('wireguardvpn'),
max_reservations=2**(F('subnetwork_mask')-F('network_mask'))).filter(
num_reservations__lt=F('max_reservations'))
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# Need to return set of tuples, see
# https://docs.djangoproject.com/en/3.1/ref/models/fields/#field-choices
return set([ (pool.subnetwork_mask, pool.subnetwork_mask) for pool in pools ])