Feature/bundle support (#15)

* openflow: Add bundle support

* openflow: Add bundle message generator and parser

* openflow: Add bundle API

lib/openflow/onf_bundle_add.ex

@@ -0,0 +1,50 @@
+defmodule Openflow.OnfBundleAdd do
+  defstruct(
+    version: 4,
+    xid: 0,
+    datapath_id: "",
+    aux_id: 0,
+    # bundle header
+    bundle_id: 0,
+    flags: [],
+    message: nil
+  )
+
+  alias __MODULE__
+
+  # ONF Experimenter
+  @experimenter 0x4F4E4600
+  # BUNDLE_ADD
+  @onf_type 2301
+
+  @onf_bundle_add_message_size 24
+
+  # experimenter
+  def ofp_type, do: 4
+
+  def new(options \\ []) do
+    %OnfBundleAdd{
+      xid: options[:xid] || 0,
+      bundle_id: options[:bundle_id] || 0,
+      flags: options[:flags] || [],
+      message: options[:message]
+    }
+  end
+
+  def to_binary(%OnfBundleAdd{} = bundle_add) do
+    bundle_id = bundle_add.bundle_id
+    message_bin = Openflow.to_binary(%{bundle_add.message | xid: bundle_add.xid})
+    length = @onf_bundle_add_message_size + byte_size(message_bin)
+    pad_length = Openflow.Utils.pad_length(length, 8)
+    flags_int = Openflow.Enums.flags_to_int(bundle_add.flags, :bundle_flags)
+
+    <<@experimenter::32, @onf_type::32, bundle_id::32, 0::2-unit(8),
+      flags_int::16, message_bin::bytes, 0::size(pad_length)-unit(8)>>
+  end
+
+  def read(<<@experimenter::32, @onf_type::32, bundle_id::32, _pad::16, flags_int::16, message_bin::bytes>>) do
+    message = Openflow.read(message_bin)
+    flags = Openflow.Enums.int_to_flags(flags_int, :bundle_flags)
+    %OnfBundleAdd{bundle_id: bundle_id, flags: flags, message: message}
+  end
+end