uncloud-mravi/uncloud_net/selectors.py
2020-12-20 21:45:47 +01:00

43 lines
1.5 KiB
Python

from django.db import transaction
from django.db.models import Count, F
from .models import *
def get_suitable_pools(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.
"""
return WireGuardVPNPool.objects.annotate(
num_reservations=Count('wireguardvpn'),
max_reservations=2**(F('subnetwork_mask')-F('network_mask'))).filter(
num_reservations__lt=F('max_reservations'),
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
"""
pools = WireGuardVPNPool.objects.annotate(num_reservations=Count('wireguardvpn'),
max_reservations=2**(F('subnetwork_mask')-F('network_mask'))).filter(
num_reservations__lt=F('max_reservations'))
# 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 ])
return set([pool.subnetwork_mask for pool in pools ])