fix bug of disconnect

sometime the node can not disconnect infinite. by using
PeerConnectionInterface::signaling_state(), I can get state of link
correctly.

Signed-off-by: Yuji Ito <llamerada.jp@gmail.com>

go/seed/seed_test.go

@@ -290,14 +290,14 @@ func TestRelayPoll(t *testing.T) {
 	assert.Len(resPoll.Packets, 1)
 	assert.Equal(packetID, resPoll.Packets[0].Id)
 
-	// get nil if the sub process finished
+	// get empty result if the sub process finished
 	ctxPoll, cancelPoll := context.WithCancel(ctx)
 	go func() {
 		resPoll, code, err := seed.poll(ctxPoll, &proto.SeedPoll{
 			SessionId: sessionID2,
 			Online:    true,
 		})
-		assert.Nil(resPoll)
+		assert.NotNil(resPoll)
 		assert.Equal(http.StatusOK, code)
 		assert.NoError(err)
 		chPoll <- resPoll

src/core/node_accessor.cpp

@@ -148,15 +148,16 @@ LinkState::Type NodeAccessor::get_link_state() const {
 void NodeAccessor::disconnect_all(std::function<void()> on_after) {
   cleanup_closing();
   if (links.size() == 0) {
+    assert(nid_links.size() == 0);
     on_after();
     return;
   }
 
   disconnect_link(first_link);
   disconnect_link(random_link);
 
-  while (nid_links.size() != 0) {
-    disconnect_link(nid_links.begin()->second);
+  for (auto& it : links) {
+    disconnect_link(it.first);
   }
 
   scheduler.add_task(this, std::bind(&NodeAccessor::disconnect_all, this, on_after), 500);
@@ -581,6 +582,7 @@ void NodeAccessor::cleanup_closing() {
       closing_link = closing_links.erase(closing_link);
 
     } else {
+      update_link_state(*link);
       // There is a link that is not closing rarely, so disconnect it.
       if (link->link_state != LinkState::CLOSING) {
         link->disconnect();

src/core/webrtc_link_native.cpp

@@ -229,6 +229,9 @@ LinkState::Type WebrtcLinkNative::get_new_link_state() {
 
   if (dco_state == LinkState::CLOSING || dco_state == LinkState::OFFLINE || pco_state == LinkState::CLOSING ||
       pco_state == LinkState::OFFLINE) {
+    if (peer_connection != nullptr && peer_connection->signaling_state() == webrtc::PeerConnectionInterface::kClosed) {
+      return LinkState::OFFLINE;
+    }
     disconnect();
     return LinkState::CLOSING;
   }