Forward data received on a faild pair and re-schedule this pair

Author: mickel8

lib/ex_ice/priv/ice_agent.ex

@@ -600,20 +600,7 @@ defmodule ExICE.Priv.ICEAgent do
         %CandidatePair{} =
           pair = Checklist.find_pair(ice_agent.checklist, local_cand.base.id, remote_cand.id)
 
-        case pair.state do
-          :succeeded ->
-            pair = Map.fetch!(ice_agent.checklist, pair.discovered_pair_id)
-            handle_data_message(ice_agent, pair, packet)
-
-          :failed ->
-            Logger.error("Received data on failed pair! Ignoring. Pair id: #{pair.id}")
-            ice_agent
-
-          _other ->
-            # We might receive data on a pair that we haven't checked
-            # on our side yet.
-            handle_data_message(ice_agent, pair, packet)
-        end
+        handle_data_message(ice_agent, pair, packet)
     end
   end
 
@@ -972,7 +959,39 @@ defmodule ExICE.Priv.ICEAgent do
     end
   end
 
+  defp handle_data_message(ice_agent, %{state: :succeeded} = pair, packet) do
+    # take final pair as local candidate might be srflx
+    pair = Map.fetch!(ice_agent.checklist, pair.discovered_pair_id)
+    do_handle_data_message(ice_agent, pair, packet)
+  end
+
+  defp handle_data_message(ice_agent, %{state: :failed} = pair, packet)
+       when ice_agent.state in [:checking, :connected] do
+    Logger.debug("""
+    Received data on failed pair. Rescheduling pair for conn check. Pair id: #{pair.id}\
+    """)
+
+    ice_agent = do_handle_data_message(ice_agent, pair, packet)
+
+    # re-schedule pair
+    pair = %{pair | state: :waiting}
+    ice_agent = put_in(ice_agent.checklist[pair.id], pair)
+    update_ta_timer(ice_agent)
+  end
+
+  defp handle_data_message(ice_agent, %{state: :failed} = pair, _packet) do
+    raise """
+    Received data on failed pair in state: #{ice_agent.state}. Pair id: #{pair.id}.
+    This should never happen.
+    """
+  end
+
+  # We might receive data on a pair that we haven't check on our side yet.
   defp handle_data_message(ice_agent, pair, packet) do
+    do_handle_data_message(ice_agent, pair, packet)
+  end
+
+  defp do_handle_data_message(ice_agent, pair, packet) do
     pair = %CandidatePair{pair | last_seen: now()}
     ice_agent = put_in(ice_agent.checklist[pair.id], pair)
 

test/priv/ice_agent_test.exs

@@ -114,7 +114,7 @@ defmodule ExICE.Priv.ICEAgentTest do
     end
   end
 
-  test "don't add pairs with srflx local candidate to the checklist" do
+  test "doesn't add pairs with srflx local candidate to the checklist" do
     ice_agent =
       ICEAgent.new(
         controlling_process: self(),
@@ -150,6 +150,38 @@ defmodule ExICE.Priv.ICEAgentTest do
     assert pair.local_cand_id == host_cand.base.id
   end
 
+  test "forwards data received on a faild pair and re-schedules" do
+    remote_cand = ExICE.Candidate.new(:host, address: {192, 168, 0, 3}, port: 8445)
+
+    ice_agent =
+      ICEAgent.new(
+        controlling_process: self(),
+        role: :controlling,
+        transport_module: Transport.Mock,
+        if_discovery_module: IfDiscovery.Mock
+      )
+      |> ICEAgent.set_remote_credentials("someufrag", "somepwd")
+      |> ICEAgent.gather_candidates()
+      |> ICEAgent.add_remote_candidate(remote_cand)
+
+    [socket] = ice_agent.sockets
+    [host_cand] = Map.values(ice_agent.local_cands)
+
+    pair = CandidatePair.new(host_cand, remote_cand, ice_agent.role, :failed)
+
+    ice_agent = %{ice_agent | checklist: %{pair.id => pair}}
+
+    ice_agent =
+      ICEAgent.handle_udp(ice_agent, socket, remote_cand.address, remote_cand.port, "some data")
+
+    # assert that data has been passed
+    assert_receive {:ex_ice, _pid, {:data, "some data"}}
+
+    # assert that pair is re-scheduled
+    assert [pair] = Map.values(ice_agent.checklist)
+    assert pair.state == :waiting
+  end
+
   describe "sends keepalives" do
     setup do
       remote_cand = ExICE.Candidate.new(:host, address: {192, 168, 0, 2}, port: 8445)