Work on test case for secure channel

test/pf.ex

@@ -0,0 +1,40 @@
+defmodule Pf do
+  use GenServer
+
+  defmodule State do
+    defstruct [
+      ifname:     nil,
+      pcap_ref:   nil,
+      tester_pid: nil
+    ]
+  end
+
+  def start_link(ifname, pid) do
+    ifname = String.to_charlist(ifname)
+    GenServer.start_link(__MODULE__, [ifname, pid])
+  end
+
+  def init([ifname, pid]) do
+    {:ok, pid} = :epcap.start_link(interface: ifname, chroot: 'priv/tmp', inject: true)
+    %State{pcap_ref: pid, ifname: ifname, tester_pid: pid}
+  end
+
+  def handle_cast({:inject, packet}, state) do
+    :epcap.send(state.pcap_ref, packet)
+    {:noreply, state}
+  end
+  def handle_cast(:stop, state) do
+    {:stop, :normal, state}
+  end
+  def handle_cast(_req, state) do
+    {:noreply, state}
+  end
+
+  def handle_info({:packet, _dlt, _time, _len, data}, state) do
+    send(state.tester_pid, data)
+    {:noreply, state}
+  end
+  def handle_info(_info, state) do
+    {:noreply, state}
+  end
+end