Handle ExDTLS errors (#60)

Author: mickel8

examples/echo/example.exs

@@ -12,16 +12,15 @@ defmodule Peer do
     ICECandidate,
     PeerConnection,
     MediaStreamTrack,
-    SessionDescription,
-    RTPTransceiver
+    SessionDescription
   }
 
   @ice_servers [
     %{urls: "stun:stun.l.google.com:19302"}
   ]
 
-  def start_link() do
-    GenServer.start_link(__MODULE__, nil)
+  def start() do
+    GenServer.start(__MODULE__, nil)
   end
 
   @impl true
@@ -189,12 +188,12 @@ defmodule Peer do
   end
 end
 
-{:ok, pid} = Peer.start_link()
+{:ok, pid} = Peer.start()
 ref = Process.monitor(pid)
 
 receive do
-  {:DOWN, ^ref, _, _, _} ->
-    Logger.info("Peer process closed. Exiting")
+  {:DOWN, ^ref, _, _, reason} ->
+    Logger.info("Peer process closed, reason: #{inspect(reason)}. Exiting")
 
   other ->
     Logger.warning("Unexpected msg. Exiting. Msg: #{inspect(other)}")

examples/save_to_file/example.exs

@@ -23,8 +23,8 @@ defmodule Peer do
     %{urls: "stun:stun.l.google.com:19302"}
   ]
 
-  def start_link() do
-    GenServer.start_link(__MODULE__, nil)
+  def start() do
+    GenServer.start(__MODULE__, nil)
   end
 
   @impl true
@@ -135,9 +135,9 @@ defmodule Peer do
 
   defp handle_ws_message(%{"type" => "peer_left"}, state) do
     # in real scenario you should probably close the PeerConnection explicitly
-    Ogg.Writer.close(state.ogg_writer)
-    IVF.Writer.close(state.ivf_writer)
     Logger.info("Remote peer left. Closing files and exiting.")
+    if state.ogg_writer, do: Ogg.Writer.close(state.ogg_writer)
+    if state.ivf_writer, do: IVF.Writer.close(state.ivf_writer)
     exit(:normal)
   end
 
@@ -217,12 +217,12 @@ defmodule Peer do
   end
 end
 
-{:ok, pid} = Peer.start_link()
+{:ok, pid} = Peer.start()
 ref = Process.monitor(pid)
 
 receive do
-  {:DOWN, ^ref, _, _, _} ->
-    Logger.info("Peer process closed. Exiting")
+  {:DOWN, ^ref, _, _, reason} ->
+    Logger.info("Peer process closed, reason: #{inspect(reason)}. Exiting")
 
   other ->
     Logger.warning("Unexpected msg. Exiting. Msg: #{inspect(other)}")

examples/save_to_file/example.html

@@ -12,9 +12,9 @@
     <main>
         <h1>Elixir WebRTC Save to File Example</h1>
     </main>
-    <button id="button" >Start</button>
+    <button id="button">Start</button>
     <video id="videoPlayer" autoplay muted></video>
     <script src="example.js"></script>
 </body>
 
-</html>
+</html>

examples/send_from_file/example.exs

@@ -29,8 +29,8 @@ defmodule Peer do
     %{urls: "stun:stun.l.google.com:19302"}
   ]
 
-  def start_link() do
-    GenServer.start_link(__MODULE__, nil)
+  def start() do
+    GenServer.start(__MODULE__, nil)
   end
 
   @impl true
@@ -269,12 +269,12 @@ defmodule Peer do
   end
 end
 
-{:ok, pid} = Peer.start_link()
+{:ok, pid} = Peer.start()
 ref = Process.monitor(pid)
 
 receive do
-  {:DOWN, ^ref, _, _, _} ->
-    Logger.info("Peer process closed. Exiting")
+  {:DOWN, ^ref, _, _, reason} ->
+    Logger.info("Peer process closed, reason: #{inspect(reason)}. Exiting")
 
   other ->
     Logger.warning("Unexpected msg. Exiting. Msg: #{inspect(other)}")

lib/ex_webrtc/dtls_transport.ex

@@ -208,8 +208,11 @@ defmodule ExWebRTC.DTLSTransport do
 
   @impl true
   def handle_info({:ex_ice, _from, {:data, _data} = msg}, state) do
-    state = handle_ice_data(msg, state)
-    {:noreply, state}
+    case handle_ice_data(msg, state) do
+      {:ok, state} -> {:noreply, state}
+      # we use shutdown to avoid logging an error
+      {:error, reason} -> {:stop, {:shutdown, reason}, state}
+    end
   end
 
   @impl true
@@ -224,12 +227,12 @@ defmodule ExWebRTC.DTLSTransport do
   end
 
   defp handle_ice_data({:data, <<f, _rest::binary>> = data}, state) when f in 20..64 do
-    # TODO: handle {:connection_closed, _}
     case ExDTLS.handle_data(state.dtls, data) do
       {:handshake_packets, packets, timeout} when state.ice_connected ->
         :ok = state.ice_transport.send_data(state.ice_pid, packets)
         Process.send_after(self(), :dtls_timeout, timeout)
-        update_dtls_state(state, :connecting)
+        state = update_dtls_state(state, :connecting)
+        {:ok, state}
 
       {:handshake_packets, packets, timeout} ->
         Logger.debug("""
@@ -239,7 +242,8 @@ defmodule ExWebRTC.DTLSTransport do
 
         Process.send_after(self(), :dtls_timeout, timeout)
         state = %{state | buffered_packets: packets}
-        update_dtls_state(state, :connecting)
+        state = update_dtls_state(state, :connecting)
+        {:ok, state}
 
       {:handshake_finished, lkm, rkm, profile, packets} ->
         Logger.debug("DTLS handshake finished")
@@ -253,19 +257,26 @@ defmodule ExWebRTC.DTLSTransport do
 
         if peer_fingerprint == state.peer_fingerprint do
           :ok = setup_srtp(state, lkm, rkm, profile)
-          update_dtls_state(state, :connected)
+          state = update_dtls_state(state, :connected)
+          {:ok, state}
         else
           Logger.debug("Non-matching peer cert fingerprint.")
-          update_dtls_state(state, :failed)
+          state = update_dtls_state(state, :failed)
+          {:ok, state}
         end
 
       {:handshake_finished, lkm, rkm, profile} ->
         Logger.debug("DTLS handshake finished")
         :ok = setup_srtp(state, lkm, rkm, profile)
-        update_dtls_state(state, :connected)
+        state = update_dtls_state(state, :connected)
+        {:ok, state}
 
       :handshake_want_read ->
-        state
+        {:ok, state}
+
+      {:error, reason} = error ->
+        Logger.debug("DTLS error: #{reason}")
+        error
     end
   end
 
@@ -285,15 +296,15 @@ defmodule ExWebRTC.DTLSTransport do
         Logger.error("Failed to decrypt SRTP/SRTCP, reason: #{inspect(reason)}")
     end
 
-    state
+    {:ok, state}
   end
 
   defp handle_ice_data({:data, _data}, state) do
     Logger.warning(
       "Received RTP/RTCP packets, but DTLS handshake hasn't been finished yet. Ignoring."
     )
 
-    state
+    {:ok, state}
   end
 
   defp setup_srtp(state, local_keying_material, remote_keying_material, profile) do