Add basic forwarding/multiplexing functionality

lib/listener.ex

@@ -0,0 +1,79 @@
+defmodule Frajtano.Listener do
+  require Logger
+  use Task
+
+  def start_link(path) do
+    Task.start_link(__MODULE__, :run, [path])
+  end
+
+  def run(path) do
+    Logger.info("Serving on path #{path}")
+    File.rm(path)
+    {:ok, sock} = :gen_tcp.listen(0, [:binary, active: false, packet: :raw, ifaddr: {:local, path}])
+    loop(sock)
+  end
+
+  def loop(sock) do
+    Logger.info("Accepting connections on #{inspect sock}")
+    {:ok, conn} = :gen_tcp.accept(sock)
+    Frajtano.ClientHandler.start(conn)
+    loop(sock)
+  end
+end
+
+defmodule Frajtano.ClientHandler do
+  alias Frajtano.Proto
+  require Logger
+
+  def start(conn) do
+    Logger.info("Got connection: #{inspect conn}")
+    Task.Supervisor.start_child(Frajtano.ClientSupervisor, fn ->
+      :gen_tcp.controlling_process(conn, self())
+      handle(conn, <<>>)
+    end)
+  end
+
+  defp handle(conn, buffer) do
+    Logger.info("Handling connection: #{inspect conn}, buffer: #{inspect buffer}")
+    case Proto.decode(buffer) do
+      {nil, buffer} -> 
+        Logger.debug("Need more data")
+        case :gen_tcp.recv(conn, 0) do
+          {:ok, msg} -> 
+            Logger.debug("Got more data: #{inspect msg}")
+            handle(conn, buffer <> msg)
+          {:error, :closed} ->
+            nil
+          {:error, error} ->
+            Logger.warning("Got network error: #{inspect error}")
+        end
+      {packet, buffer} ->
+        :gen_tcp.send(conn, Proto.encode(handle_packet(packet)))
+        handle(conn, buffer)
+    end
+  end
+
+  defp handle_packet({:agentc_request_identities, nil}) do
+    Logger.info("Got identities request")
+    case Frajtano.Agent.identities() do
+      {:ok, identities} -> {:agent_identities_answer, identities}
+      {:error, error} ->
+        Logger.warning("Error fetching identities: #{error}")
+        {:agent_failure, nil}
+    end
+  end
+  
+  defp handle_packet({:agentc_sign_request, request}) do
+    case Frajtano.Agent.sign(request) do
+      {:ok, signature} -> {:agent_sign_response, signature}
+      {:error, error} ->
+        Logger.warning("Error signing: #{error}")
+        {:agent_failure, nil}
+    end
+  end
+
+  defp handle_packet({type, body}) do
+    Logger.warning("Can't handle #{type} packet with body #{inspect body}")
+    {:agent_failure, nil}
+  end
+end