vcl/ldp: add write msg function and fine tuning

Allows app to push data. Additionally, ensure reset/close replies are
not sent unless vcl closes the session.

Change-Id: Icbbf933cf57b55cfbcc7b802af0f83919a066f65
Signed-off-by: Florin Coras <fcoras@cisco.com>

2 files changed, 31 insertions, 6 deletions

diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index cbe0dd76430..d30254e5fc0 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -234,6 +234,7 @@ session_alloc_for_connection (transport_connection_t * tc)
   s = session_alloc (thread_index);
   s->session_type = session_type_from_proto_and_ip (tc->proto, tc->is_ip4);
   s->enqueue_epoch = (u64) ~ 0;
+  s->session_state = SESSION_STATE_CLOSED;
 
   /* Attach transport to session and vice versa */
   s->connection_index = tc->c_index;
@@ -773,6 +774,7 @@ stream_session_accept_notify (transport_connection_t * tc)
   app_wrk = app_worker_get_if_valid (s->app_wrk_index);
   if (!app_wrk)
     return -1;
+  s->session_state = SESSION_STATE_ACCEPTING;
   app = application_get (app_wrk->app_index);
   return app->cb_fns.session_accept_callback (s);
 }
@@ -824,6 +826,7 @@ session_transport_delete_notify (transport_connection_t * tc)
 
   switch (s->session_state)
     {
+    case SESSION_STATE_ACCEPTING:
     case SESSION_STATE_TRANSPORT_CLOSING:
       /* If transport finishes or times out before we get a reply
        * from the app, mark transport as closed and wait for reply
@@ -844,11 +847,13 @@ session_transport_delete_notify (transport_connection_t * tc)
       s->session_state = SESSION_STATE_TRANSPORT_CLOSED;
       session_program_transport_close (s);
       break;
+    case SESSION_STATE_TRANSPORT_CLOSED:
+      break;
     case SESSION_STATE_CLOSED:
-    case SESSION_STATE_ACCEPTING:
       session_delete (s);
       break;
     default:
+      clib_warning ("session state %u", s->session_state);
       session_delete (s);
       break;
     }
@@ -869,7 +874,16 @@ session_transport_closed_notify (transport_connection_t * tc)
 
   if (!(s = session_get_if_valid (tc->s_index, tc->thread_index)))
     return;
-  s->session_state = SESSION_STATE_CLOSED;
+
+  /* If app close has not been received or has not yet resulted in
+   * a transport close, only mark the session transport as closed */
+  if (s->session_state <= SESSION_STATE_CLOSING)
+    {
+      session_lookup_del_session (s);
+      s->session_state = SESSION_STATE_TRANSPORT_CLOSED;
+    }
+  else
+    s->session_state = SESSION_STATE_CLOSED;
 }
 
 /**
@@ -913,7 +927,6 @@ stream_session_accept (transport_connection_t * tc, u32 listener_index,
 
   s->app_wrk_index = app_wrk->wrk_index;
   s->listener_index = listener_index;
-  s->session_state = SESSION_STATE_ACCEPTING;
 
   /* Shoulder-tap the server */
   if (notify)
@@ -1141,7 +1154,7 @@ void
 session_transport_close (stream_session_t * s)
 {
   /* If transport is already closed, just free the session */
-  if (s->session_state == SESSION_STATE_TRANSPORT_CLOSED)
+  if (s->session_state >= SESSION_STATE_TRANSPORT_CLOSED)
     {
       session_free_w_fifos (s);
       return;
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index 4323ed83cf8..45018daf45a 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -29,6 +29,7 @@ session_mq_accepted_reply_handler (void *data)
 {
   session_accepted_reply_msg_t *mp = (session_accepted_reply_msg_t *) data;
   vnet_disconnect_args_t _a = { 0 }, *a = &_a;
+  stream_session_state_t old_state;
   app_worker_t *app_wrk;
   local_session_t *ls;
   stream_session_t *s;
@@ -64,18 +65,29 @@ session_mq_accepted_reply_handler (void *data)
   else
     {
       s = session_get_from_handle_if_valid (mp->handle);
-      /* Closed while waiting for app to reply */
-      if (!s || s->session_state > SESSION_STATE_READY)
+      if (!s)
 	return;
+
       app_wrk = app_worker_get (s->app_wrk_index);
       if (app_wrk->app_index != mp->context)
 	{
 	  clib_warning ("app doesn't own session");
 	  return;
 	}
+
+      old_state = s->session_state;
       s->session_state = SESSION_STATE_READY;
       if (!svm_fifo_is_empty (s->server_rx_fifo))
 	app_worker_lock_and_send_event (app_wrk, s, FIFO_EVENT_APP_RX);
+
+      /* Closed while waiting for app to reply. Resend disconnect */
+      if (old_state >= SESSION_STATE_TRANSPORT_CLOSING)
+	{
+	  application_t *app = application_get (app_wrk->app_index);
+	  app->cb_fns.session_disconnect_callback (s);
+	  s->session_state = old_state;
+	  return;
+	}
     }
 }