;o custom subnets

1 files changed, 84 insertions, 0 deletions

diff --git a/lib/lsg/subnet.ex b/lib/lsg/subnet.ex
new file mode 100644
index 0000000..81bd862
--- /dev/null
+++ b/lib/lsg/subnet.ex
@@ -0,0 +1,84 @@
+defmodule LSG.Subnet do
+  use Agent
+
+  def start_link(_) do
+    Agent.start_link(&setup/0, name: __MODULE__)
+  end
+
+  def assignations() do
+    :dets.select(dets(), [{{:"$1", :"$2"}, [is_binary: :"$2"], [{{:"$1", :"$2"}}]}])
+  end
+
+  def find_subnet_for(binary) when is_binary(binary) do
+    case :dets.select(dets(), [{{:"$1", :"$2"}, [{:==, :"$2", binary}], [{{:"$1", :"$2"}}]}]) do
+      [{subnet, _}] -> subnet
+      _ -> nil
+    end
+  end
+
+  def assign(binary) when is_binary(binary) do
+    result = if subnet = find_subnet_for(binary) do
+      {:ok, subnet}
+    else
+      Agent.get_and_update(__MODULE__, fn(dets) ->
+        {subnet, _} = available_select(dets)
+        :dets.insert(dets, {subnet, binary})
+        :dets.sync(dets)
+        {{:new, subnet}, dets}
+      end)
+    end
+
+    case result do
+      {:new, subnet} ->
+        ip = Pfx.host(subnet, 1)
+        set_reverse(binary, ip)
+        subnet
+      {:ok, subnet} ->
+        subnet
+    end
+  end
+
+  def set_reverse(name, ip, value \\ nil)
+
+  def set_reverse(name, ip, nil) do
+    set_reverse(name, ip, "#{name}.users.goulag.org")
+  end
+
+  def set_reverse(_, ip, value) do
+    ptr_zone = "3.0.0.2.d.f.0.a.2.ip6.arpa"
+    ip_fqdn = Pfx.dns_ptr(ip)
+    ip_local = String.replace(ip_fqdn, ".#{ptr_zone}", "")
+    rev? = String.ends_with?(value, ".users.goulag.org")
+    if rev? do
+      {:ok, rev_zone} = PowerDNSex.show_zone("users.goulag.org")
+      rev_update? = Enum.any?(rev_zone.rrsets, fn(rr) -> rr.name == "#{ip_fqdn}." end)
+      record = %{name: "#{value}.", type: "AAAA", ttl: 8600, records: [%{content: ip, disabled: false}]}
+      if(rev_update?, do: PowerDNSex.update_record(rev_zone, record), else: PowerDNSex.create_record(rev_zone, record))
+    end
+    {:ok, zone} = PowerDNSex.show_zone(ptr_zone)
+    update? = Enum.any?(zone.rrsets, fn(rr) -> rr.name == "#{ip_fqdn}." end)
+    record = %{name: "#{ip_fqdn}.", type: "PTR", ttl: 3600, records: [%{content: "#{value}.", disabled: false}]}
+    pdns = if(update?, do: PowerDNSex.update_record(zone, record), else: PowerDNSex.create_record(zone, record))
+    :ok
+  end
+
+  @doc false
+  def dets() do
+    (LSG.data_path() <> "/subnets.dets") |> String.to_charlist()
+  end
+
+  @doc false
+  def setup() do
+    {:ok, dets} = :dets.open_file(dets(), [])
+    dets
+  end
+
+  defp available_select(dets) do
+    spec = [{{:"$1", :"$2"}, [is_integer: :"$2"], [{{:"$1", :"$2"}}]}]
+    {subnets, _} = :dets.select(dets, spec, 20)
+    subnet = subnets
+    |> Enum.sort_by(fn({_, last}) -> last end)
+    |> List.first()
+  end
+
+end