Refactor nova-net cidr validation in prep for bug fix

The network manager create_networks function is on the verge of the
"too complex" pep8 check error, so this change refactors the cidr
validation code out into a private function in preparation for
fixing a bug.

Change-Id: Id0603ddd642acccfa12ae53a52ecfb66dca53702

1 files changed, 35 insertions, 32 deletions

diff --git a/nova/network/manager.py b/nova/network/manager.py
index ea3098b142..1e8d2459e7 100644
--- a/nova/network/manager.py
+++ b/nova/network/manager.py
@@ -1227,6 +1227,40 @@ class NetworkManager(manager.Manager):
             raise exception.AddressOutOfRange(address=ip, cidr=str(subnet))
         return index
 
+    def _validate_cidr(self, context, nets, subnets_v4, fixed_net_v4):
+        used_subnets = [net.cidr for net in nets]
+
+        def find_next(subnet):
+            next_subnet = subnet.next()
+            while next_subnet in subnets_v4:
+                next_subnet = next_subnet.next()
+            if next_subnet in fixed_net_v4:
+                return next_subnet
+
+        for subnet in list(subnets_v4):
+            if subnet in used_subnets:
+                next_subnet = find_next(subnet)
+                if next_subnet:
+                    subnets_v4.remove(subnet)
+                    subnets_v4.append(next_subnet)
+                    subnet = next_subnet
+                else:
+                    raise exception.CidrConflict(cidr=subnet,
+                                                 other=subnet)
+            for used_subnet in used_subnets:
+                if subnet in used_subnet:
+                    raise exception.CidrConflict(cidr=subnet,
+                                                 other=used_subnet)
+                if used_subnet in subnet:
+                    next_subnet = find_next(subnet)
+                    if next_subnet:
+                        subnets_v4.remove(subnet)
+                        subnets_v4.append(next_subnet)
+                        subnet = next_subnet
+                    else:
+                        raise exception.CidrConflict(cidr=subnet,
+                                                     other=used_subnet)
+
     def _do_create_networks(self, context,
                             label, cidr, multi_host, num_networks,
                             network_size, cidr_v6, gateway, gateway_v6, bridge,
@@ -1271,38 +1305,7 @@ class NetworkManager(manager.Manager):
             except exception.NoNetworksFound:
                 nets = []
             num_used_nets = len(nets)
-            used_subnets = [net.cidr for net in nets]
-
-            def find_next(subnet):
-                next_subnet = subnet.next()
-                while next_subnet in subnets_v4:
-                    next_subnet = next_subnet.next()
-                if next_subnet in fixed_net_v4:
-                    return next_subnet
-
-            for subnet in list(subnets_v4):
-                if subnet in used_subnets:
-                    next_subnet = find_next(subnet)
-                    if next_subnet:
-                        subnets_v4.remove(subnet)
-                        subnets_v4.append(next_subnet)
-                        subnet = next_subnet
-                    else:
-                        raise exception.CidrConflict(cidr=subnet,
-                                                     other=subnet)
-                for used_subnet in used_subnets:
-                    if subnet in used_subnet:
-                        raise exception.CidrConflict(cidr=subnet,
-                                                     other=used_subnet)
-                    if used_subnet in subnet:
-                        next_subnet = find_next(subnet)
-                        if next_subnet:
-                            subnets_v4.remove(subnet)
-                            subnets_v4.append(next_subnet)
-                            subnet = next_subnet
-                        else:
-                            raise exception.CidrConflict(cidr=subnet,
-                                                         other=used_subnet)
+            self._validate_cidr(context, nets, subnets_v4, fixed_net_v4)
 
         networks = objects.NetworkList(context=context, objects=[])
         subnets = itertools.izip_longest(subnets_v4, subnets_v6)