Openflow parser

lib/openflow/multipart/group/reply.ex

@@ -0,0 +1,69 @@
+defmodule Openflow.Multipart.Group.Reply do
+  defstruct(
+    version:      4,
+    xid:          0,
+    datapath_id:  nil, # virtual field
+    flags:        [],
+    groups:       []
+  )
+
+  alias __MODULE__
+
+  def ofp_type, do: 18
+
+  def new(groups \\ []) do
+    %Reply{groups: groups}
+  end
+
+  def read(<<groups_bin::bytes>>) do
+    groups = Openflow.Multipart.Group.read(groups_bin)
+    %Reply{groups: groups}
+  end
+end
+
+defmodule Openflow.Multipart.Group do
+  defstruct(
+    group_id:      0,
+    ref_count:     0,
+    packet_count:  0,
+    byte_count:    0,
+    duration_sec:  0,
+    duration_nsec: 0,
+    bucket_stats:  []
+  )
+
+  @ofp_group_stats_size 40
+
+  alias __MODULE__
+
+  def read(binary) do
+    do_read([], binary)
+  end
+
+  # private functions
+
+  defp do_read(acc, ""), do: Enum.reverse(acc)
+  defp do_read(acc, <<length::16, _binary::bytes>> = binary) do
+    <<group_bin::size(length)-bytes, rest::bytes>> = binary
+    do_read([codec(group_bin)|acc], rest)
+  end
+
+  defp codec(<<length::16, _::size(2)-unit(8),
+               group_id::32, ref_count::32,
+               _::size(4)-unit(8), packet_count::64,
+               byte_count::64, duration_sec::32,
+               duration_nsec::32, tail::bytes>>) do
+    bucket_stats_size = length - @ofp_group_stats_size
+    <<bucket_stats_bin::size(bucket_stats_size)-bytes, _rest::bytes>> = tail
+    bucket_stats = for <<packet_count::64, byte_count::64 <- bucket_stats_bin>> do
+      %{packet_count: packet_count, byte_count: byte_count}
+    end
+    %Group{group_id: group_id,
+           ref_count: ref_count,
+           packet_count: packet_count,
+           byte_count: byte_count,
+           duration_sec: duration_sec,
+           duration_nsec: duration_nsec,
+           bucket_stats: bucket_stats}
+  end
+end