[vpn] make a vpn creat-able!

[15:40] line:~% http -a nicoschottelius:$(pass ungleich.ch/nico.schottelius@ungleich.ch)  http://localhost:8000/net/vpn/ network_size=48  wireguard_public_key=$(wg genkey | wg pubkey)
HTTP/1.1 201 Created
Allow: GET, POST, HEAD, OPTIONS
Content-Length: 206
Content-Type: application/json
Date: Sun, 12 Apr 2020 13:40:26 GMT
Server: WSGIServer/0.2 CPython/3.7.3
Vary: Accept
X-Content-Type-Options: nosniff
X-Frame-Options: DENY

{
    "extra_data": null,
    "network": "2a0a:e5c1:203::",
    "order": null,
    "owner": 30,
    "status": "PENDING",
    "uuid": "8f977a8f-e06a-4346-94ae-8f525df58b7b",
    "wireguard_public_key": "JvCuUTZHm9unasJkGsLKN0Bf/hu6ZSIv7dnIGPyJ6xA="
}

uncloud_django_based/uncloud/uncloud_net/models.py

@@ -47,11 +47,15 @@ class VPNPool(UncloudModel):
         maximum_networks = 2^(24-8)
         """
 
-        return 2**(subnetwork_size - network_size)
+        return 2**(self.subnetwork_size - self.network_size)
 
     @property
     def used_networks(self):
-        return self.vpnnetworkreservation_set.objects.filter(vpnpool=self, status='used')
+        return self.vpnnetworkreservation_set.filter(vpnpool=self, status='used')
+
+    @property
+    def free_networks(self):
+        return self.vpnnetworkreservation_set.filter(vpnpool=self, status='free')
 
     @property
     def num_used_networks(self):
@@ -59,27 +63,18 @@ class VPNPool(UncloudModel):
 
     @property
     def num_free_networks(self):
-        return self.num_maximum_networks - self.num_used_networks
+        return self.num_maximum_networks - self.num_used_networks + len(self.free_networks)
 
     @property
     def next_free_network(self):
-        free_net = self.vpnnetworkreservation_set.objects.filter(vpnpool=self,
-                                                                 status='free')
-
-        used_net = self.vpnnetworkreservation_set.objects.filter(vpnpool=self,
-                                                                 status='used')
-
-        this_net = ipaddress.ip_network("{}/{}".format(
-            self.network, self.network_size))
-
-
-        if num_free_networks == 0:
+        if self.num_free_networks == 0:
+            # FIXME: use right exception
             raise Exception("No free networks")
 
-        if len(free_net) > 0:
-            return free_net[0].address
+        if len(self.free_networks) > 0:
+            return self.free_networks[0].address
 
-        if len(used_net) > 0:
+        if len(self.used_networks) > 0:
             """
             sample:
 
@@ -89,7 +84,7 @@ class VPNPool(UncloudModel):
             next:
             """
 
-            last_net = ipaddress.ip_network(self.used_networks.last())
+            last_net = ipaddress.ip_network(self.used_networks.last().address)
             last_net_ip = last_net[0]
 
             if last_net_ip.version == 6:
@@ -99,7 +94,52 @@ class VPNPool(UncloudModel):
 
             next_net_ip = last_net_ip + offset_to_next
 
-            return next_net_ip
+            return str(next_net_ip)
+        else:
+            # first network to be created
+            return self.network
+
+    @property
+    def wireguard_config_filename(self):
+        return '/etc/wireguard/{}.conf'.format(self.network)
+
+    @property
+    def wireguard_config(self):
+        wireguard_config = [
+            """
+[Interface]
+ListenPort = 51820
+PrivateKey = {privatekey}
+""".format(privatekey=self.wireguard_private_key) ]
+
+        peers = []
+
+        for vpnnetwork in self.vpnnetworkreservation_set:
+            public_key = vpnnetwork.wireguard_public_key
+            peer_network = "{}/{}".format(vpnnetwork.address, self.subnetwork_size)
+
+            peers.append("""
+[Peer]
+PublicKey = {public_key}
+AllowedIPs = {peer_network}
+""")
+
+        wireguard_config.extend(peers)
+
+        return "\n".join(wireguard_config)
+
+
+    def configure_wireguard_vpnserver(self):
+        """
+        This method is designed to run as a celery task and should
+        not be called directly from the web
+        """
+
+        # subprocess, ssh
+
+        pass
+
+
 
 
 
@@ -109,6 +149,7 @@ class VPNNetworkReservation(UncloudModel):
      """
     vpnpool = models.ForeignKey(VPNPool,
                                  on_delete=models.CASCADE)
+
     address = models.GenericIPAddressField(primary_key=True)
 
     status = models.CharField(max_length=256,