add function to get subnets to schema

This also adds a view to get a list of all containers and their free
space in between.
This is needed for ippool_list to get a nice overview over everything.

schema/01_initial.sql

@@ -20,19 +20,31 @@ create table if not exists pools(
   primary key(layer3domain_id, id)
 );
 
-create table if not exists containers(
-  layer3domain_id integer not null references layer3domains(id),
-  network cidr not null,
-  pool_id integer,
+create table containers(
+	layer3domain_id integer not null references layer3domains(id),
+ 	subnet cidr not null,
+ 	pool_id integer,
+  attributes jsonb not null default '{}'::jsonb,
   created_at timestamptz not null default now(),
   created_by varchar(128) not null,
   modified_at timestamptz not null default now(),
   modified_by varchar(128) not null,
-  attributes jsonb not null default '{}'::jsonb,
-  unique(layer3domain_id, network),
-  foreign key (layer3domain_id, pool_id) references pools(layer3domain_id, id)
+ 	unique(layer3domain_id, subnet),
+	foreign key (layer3domain_id, pool_id) references pools(layer3domain_id, id)
 );
-create index if not exists container_reference_key on containers(layer3domain_id, pool_id, network);
+
+create or replace view containers_tree as
+select
+	c.layer3domain_id,
+  c.subnet,
+  array_agg(p.subnet order by p.subnet) filter (where p.subnet is not null) as parents
+from containers c
+left join containers p
+  on c.subnet << p.subnet
+  and c.layer3domain_id = p.layer3domain_id
+group by c.layer3domain_id, c.subnet
+order by c.layer3domain_id, c.subnet;
+comment on view containers_tree is 'This returns a tree of all containers so that sub trees can be shown.';
 
 create table if not exists ips(
   layer3domain_id integer not null,
@@ -184,3 +196,50 @@ create trigger trg_zones before insert or update or delete on zones for each row
 create trigger trg_zoneviews before insert or update or delete on zoneviews for each row execute function record();
 create trigger trg_zoneviews_outputgroups before insert or update or delete on zoneviews_outputgroups for each row execute function record();
 
+create or replace function subnets_between(net_start inet, net_end inet) returns setof cidr as $$
+declare
+        common cidr;
+        mask int;
+begin
+        net_start := host(net_start)::inet;
+        net_end   := host(net_end)::inet;
+        -- check if net_start and net_end are in the same subnet
+        common := inet_merge(host(net_start)::inet, host(net_end)::inet);
+        mask := masklen(common);
+        if set_masklen(net_start, mask) = common and broadcast(common) = set_masklen(net_end, mask) then
+                return next common;
+                return;
+        end if;
+        -- subnet is too big, so make it smaller
+        return query select * from subnets_between(net_start, broadcast(set_masklen(net_start, mask + 1)));
+        return query select * from subnets_between(network(set_masklen(net_end, mask + 1)), net_end);
+end;
+$$ language plpgsql;
+comment on function subnets_between(inet, inet) is 'get a list of subnets between two IPs.';
+
+create or replace view containers_free_list as
+with subnets as (
+        select
+                c.layer3domain_id,
+                c.subnet,
+                ct.subnet child,
+                lag(ct.subnet) over (partition by c.subnet order by ct.subnet) has_before,
+                lead(ct.subnet) over (partition by c.subnet order by ct.subnet) has_after,
+                parents
+        from containers c
+        join containers_tree ct on c.layer3domain_id = ct.layer3domain_id and c.subnet = ct.parents[array_length(ct.parents, 1)]
+                                where host(c.subnet) != host(ct.subnet) and host(broadcast(c.subnet)) != host(broadcast(ct.subnet))
+)
+select * from (
+        select layer3domain_id, parents, 'available' state, ls as subnet
+					from subnets, lateral subnets_between(subnet, child - 1) ls
+				 where has_before is null
+        union all
+        select layer3domain_id, parents, 'available', ls
+					from subnets, lateral subnets_between(broadcast(child) + 1, broadcast(subnet)) ls
+				 where has_after is null
+        union all
+        select layer3domain_id, parents, 'container', subnet
+					from containers_tree
+) freelist order by layer3domain_id, subnet;
+comment on view containers_free_list is 'Creates a list of free space between other containers.';