session: improve error reporting

Type: improvement

Change-Id: I9dd850a1ce85b0adb5136233f176117e0ee38817
Signed-off-by: Florin Coras <fcoras@cisco.com>

31 files changed, 199 insertions, 160 deletions

diff --git a/src/plugins/hs_apps/echo_client.c b/src/plugins/hs_apps/echo_client.c
index 551e46b987e..3c55c6dc720 100644
--- a/src/plugins/hs_apps/echo_client.c
+++ b/src/plugins/hs_apps/echo_client.c
@@ -362,7 +362,8 @@ echo_clients_init (vlib_main_t * vm)
 
 static int
 quic_echo_clients_qsession_connected_callback (u32 app_index, u32 api_context,
-					       session_t * s, u8 is_fail)
+					       session_t * s,
+					       session_error_t err)
 {
   echo_client_main_t *ecm = &echo_client_main;
   vnet_connect_args_t *a = 0;
@@ -406,7 +407,8 @@ quic_echo_clients_qsession_connected_callback (u32 app_index, u32 api_context,
 
 static int
 quic_echo_clients_session_connected_callback (u32 app_index, u32 api_context,
-					      session_t * s, u8 is_fail)
+					      session_t * s,
+					      session_error_t err)
 {
   echo_client_main_t *ecm = &echo_client_main;
   eclient_session_t *session;
@@ -416,7 +418,7 @@ quic_echo_clients_session_connected_callback (u32 app_index, u32 api_context,
   if (PREDICT_FALSE (ecm->run_test != ECHO_CLIENTS_STARTING))
     return -1;
 
-  if (is_fail)
+  if (err)
     {
       clib_warning ("connection %d failed!", api_context);
       ecm->run_test = ECHO_CLIENTS_EXITING;
@@ -427,7 +429,7 @@ quic_echo_clients_session_connected_callback (u32 app_index, u32 api_context,
   if (s->listener_handle == SESSION_INVALID_HANDLE)
     return quic_echo_clients_qsession_connected_callback (app_index,
 							  api_context, s,
-							  is_fail);
+							  err);
   DBG ("STREAM Connection callback %d", api_context);
 
   thread_index = s->thread_index;
@@ -479,7 +481,7 @@ quic_echo_clients_session_connected_callback (u32 app_index, u32 api_context,
 
 static int
 echo_clients_session_connected_callback (u32 app_index, u32 api_context,
-					 session_t * s, u8 is_fail)
+					 session_t * s, session_error_t err)
 {
   echo_client_main_t *ecm = &echo_client_main;
   eclient_session_t *session;
@@ -489,7 +491,7 @@ echo_clients_session_connected_callback (u32 app_index, u32 api_context,
   if (PREDICT_FALSE (ecm->run_test != ECHO_CLIENTS_STARTING))
     return -1;
 
-  if (is_fail)
+  if (err)
     {
       clib_warning ("connection %d failed!", api_context);
       ecm->run_test = ECHO_CLIENTS_EXITING;
diff --git a/src/plugins/hs_apps/echo_server.c b/src/plugins/hs_apps/echo_server.c
index 362d278119c..c8335e3d813 100644
--- a/src/plugins/hs_apps/echo_server.c
+++ b/src/plugins/hs_apps/echo_server.c
@@ -125,7 +125,7 @@ echo_server_session_reset_callback (session_t * s)
 
 int
 echo_server_session_connected_callback (u32 app_index, u32 api_context,
-					session_t * s, u8 is_fail)
+					session_t * s, session_error_t err)
 {
   clib_warning ("called...");
   return -1;
diff --git a/src/plugins/hs_apps/http_server.c b/src/plugins/hs_apps/http_server.c
index cc998a6f661..ab3bab15b10 100644
--- a/src/plugins/hs_apps/http_server.c
+++ b/src/plugins/hs_apps/http_server.c
@@ -690,7 +690,7 @@ http_server_session_reset_callback (session_t * s)
 
 static int
 http_server_session_connected_callback (u32 app_index, u32 api_context,
-					session_t * s, u8 is_fail)
+					session_t * s, session_error_t err)
 {
   clib_warning ("called...");
   return -1;
diff --git a/src/plugins/hs_apps/proxy.c b/src/plugins/hs_apps/proxy.c
index ca46aef2ae0..83b26222adb 100644
--- a/src/plugins/hs_apps/proxy.c
+++ b/src/plugins/hs_apps/proxy.c
@@ -211,7 +211,7 @@ proxy_reset_callback (session_t * s)
 
 static int
 proxy_connected_callback (u32 app_index, u32 api_context,
-			  session_t * s, u8 is_fail)
+			  session_t * s, session_error_t err)
 {
   clib_warning ("called...");
   return -1;
@@ -363,13 +363,13 @@ static session_cb_vft_t proxy_session_cb_vft = {
 
 static int
 active_open_connected_callback (u32 app_index, u32 opaque,
-				session_t * s, u8 is_fail)
+				session_t * s, session_error_t err)
 {
   proxy_main_t *pm = &proxy_main;
   proxy_session_t *ps;
   u8 thread_index = vlib_get_thread_index ();
 
-  if (is_fail)
+  if (err)
     {
       clib_warning ("connection %d failed!", opaque);
       return 0;
diff --git a/src/plugins/http_static/static_server.c b/src/plugins/http_static/static_server.c
index 888cf416e80..8945ee35036 100644
--- a/src/plugins/http_static/static_server.c
+++ b/src/plugins/http_static/static_server.c
@@ -1118,7 +1118,8 @@ http_static_server_session_reset_callback (session_t * s)
 
 static int
 http_static_server_session_connected_callback (u32 app_index, u32 api_context,
-					       session_t * s, u8 is_fail)
+					       session_t * s,
+					       session_error_t err)
 {
   clib_warning ("called...");
   return -1;
diff --git a/src/plugins/quic/quic.c b/src/plugins/quic/quic.c
index 14002a253d7..4d809446130 100644
--- a/src/plugins/quic/quic.c
+++ b/src/plugins/quic/quic.c
@@ -1258,18 +1258,19 @@ quic_connect_stream (session_t * quic_session, session_endpoint_cfg_t * sep)
   stream_session->session_state = SESSION_STATE_READY;
 
   /* For now we only reset streams. Cleanup will be triggered by timers */
-  if (app_worker_init_connected (app_wrk, stream_session))
+  if ((rv = app_worker_init_connected (app_wrk, stream_session)))
     {
       QUIC_ERR ("failed to app_worker_init_connected");
       quicly_reset_stream (stream, QUIC_APP_CONNECT_NOTIFY_ERROR);
-      return app_worker_connect_notify (app_wrk, NULL, sep->opaque);
+      return app_worker_connect_notify (app_wrk, NULL, rv, sep->opaque);
     }
 
   svm_fifo_add_want_deq_ntf (stream_session->rx_fifo,
 			     SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL |
 			     SVM_FIFO_WANT_DEQ_NOTIF_IF_EMPTY);
 
-  if (app_worker_connect_notify (app_wrk, stream_session, sep->opaque))
+  if (app_worker_connect_notify (app_wrk, stream_session, SESSION_E_NONE,
+				 sep->opaque))
     {
       QUIC_ERR ("failed to notify app");
       quic_increment_counter (QUIC_ERROR_CLOSED_STREAM, 1);
@@ -1612,17 +1613,17 @@ quic_on_quic_session_connected (quic_ctx_t * ctx)
 
   /* If quic session connected fails, immediatly close connection */
   app_wrk = app_worker_get (ctx->parent_app_wrk_id);
-  if (app_worker_init_connected (app_wrk, quic_session))
+  if ((rv = app_worker_init_connected (app_wrk, quic_session)))
     {
       QUIC_ERR ("failed to app_worker_init_connected");
       quic_proto_on_close (ctx_id, thread_index);
-      app_worker_connect_notify (app_wrk, NULL, ctx->client_opaque);
+      app_worker_connect_notify (app_wrk, NULL, rv, ctx->client_opaque);
       return;
     }
 
   quic_session->session_state = SESSION_STATE_CONNECTING;
   if ((rv = app_worker_connect_notify (app_wrk, quic_session,
-				       ctx->client_opaque)))
+				       SESSION_E_NONE, ctx->client_opaque)))
     {
       QUIC_ERR ("failed to notify app %d", rv);
       quic_proto_on_close (ctx_id, thread_index);
@@ -1739,7 +1740,8 @@ quic_transfer_connection (u32 ctx_index, u32 dest_thread)
 
 static int
 quic_udp_session_connected_callback (u32 quic_app_index, u32 ctx_index,
-				     session_t * udp_session, u8 is_fail)
+				     session_t * udp_session,
+				     session_error_t err)
 {
   QUIC_DBG (2, "QSession is now connected (id %u)",
 	    udp_session->session_index);
@@ -1759,14 +1761,14 @@ quic_udp_session_connected_callback (u32 quic_app_index, u32 ctx_index,
 
 
   ctx = quic_ctx_get (ctx_index, thread_index);
-  if (is_fail)
+  if (err)
     {
       u32 api_context;
       app_wrk = app_worker_get_if_valid (ctx->parent_app_wrk_id);
       if (app_wrk)
 	{
 	  api_context = ctx->c_s_index;
-	  app_worker_connect_notify (app_wrk, 0, api_context);
+	  app_worker_connect_notify (app_wrk, 0, SESSION_E_NONE, api_context);
 	}
       return 0;
     }
diff --git a/src/plugins/tlsmbedtls/tls_mbedtls.c b/src/plugins/tlsmbedtls/tls_mbedtls.c
index dafb0900805..7b722faf822 100644
--- a/src/plugins/tlsmbedtls/tls_mbedtls.c
+++ b/src/plugins/tlsmbedtls/tls_mbedtls.c
@@ -414,11 +414,11 @@ mbedtls_ctx_handshake_rx (tls_ctx_t * ctx)
 	   */
 	  if (ctx->srv_hostname)
 	    {
-	      tls_notify_app_connected (ctx, /* is failed */ 0);
+	      tls_notify_app_connected (ctx, SESSION_E_TLS_HANDSHAKE);
 	      return -1;
 	    }
 	}
-      tls_notify_app_connected (ctx, /* is failed */ 0);
+      tls_notify_app_connected (ctx, SESSION_E_NONE);
     }
   else
     {
diff --git a/src/plugins/tlsopenssl/tls_openssl.c b/src/plugins/tlsopenssl/tls_openssl.c
index 6d0364c3acb..43bb13ff967 100644
--- a/src/plugins/tlsopenssl/tls_openssl.c
+++ b/src/plugins/tlsopenssl/tls_openssl.c
@@ -317,7 +317,7 @@ openssl_handle_handshake_failure (tls_ctx_t * ctx)
       /*
        * Also handles cleanup of the pre-allocated session
        */
-      tls_notify_app_connected (ctx, /* is failed */ 1);
+      tls_notify_app_connected (ctx, SESSION_E_TLS_HANDSHAKE);
     }
 }
 
@@ -385,11 +385,11 @@ openssl_ctx_handshake_rx (tls_ctx_t * ctx, session_t * tls_session)
 	   */
 	  if (ctx->srv_hostname)
 	    {
-	      tls_notify_app_connected (ctx, /* is failed */ 0);
+	      tls_notify_app_connected (ctx, SESSION_E_TLS_HANDSHAKE);
 	      return -1;
 	    }
 	}
-      tls_notify_app_connected (ctx, /* is failed */ 0);
+      tls_notify_app_connected (ctx, SESSION_E_NONE);
     }
   else
     {
diff --git a/src/plugins/unittest/segment_manager_test.c b/src/plugins/unittest/segment_manager_test.c
index 8f362f40cb6..4992e2e1670 100644
--- a/src/plugins/unittest/segment_manager_test.c
+++ b/src/plugins/unittest/segment_manager_test.c
@@ -39,7 +39,7 @@ dummy_session_reset_callback (session_t * s)
 
 static int
 dummy_session_connected_callback (u32 app_index, u32 api_context,
-				  session_t * s, u8 is_fail)
+				  session_t * s, session_error_t err)
 {
   clib_warning ("called...");
   return 0;
diff --git a/src/plugins/unittest/session_test.c b/src/plugins/unittest/session_test.c
index 8d5566feb46..9368f9f80f7 100644
--- a/src/plugins/unittest/session_test.c
+++ b/src/plugins/unittest/session_test.c
@@ -54,7 +54,7 @@ volatile u32 connected_session_index = ~0;
 volatile u32 connected_session_thread = ~0;
 int
 dummy_session_connected_callback (u32 app_index, u32 api_context,
-				  session_t * s, u8 is_fail)
+				  session_t * s, session_error_t err)
 {
   if (s)
     {
@@ -596,7 +596,7 @@ session_test_namespace (vlib_main_t * vm, unformat_input_t * input)
   connect_args.app_index = client_index;
   error = vnet_connect (&connect_args);
   SESSION_TEST ((error != 0), "client connect should return error code");
-  SESSION_TEST ((error == VNET_API_ERROR_INVALID_VALUE),
+  SESSION_TEST ((error == SESSION_E_INVALID_RMT_IP),
 		"error code should be invalid value (zero ip)");
   SESSION_TEST ((dummy_segment_count == 0),
 		"shouldn't have received request to map new segment");
@@ -678,8 +678,8 @@ session_test_namespace (vlib_main_t * vm, unformat_input_t * input)
   vnet_application_attach (&attach_args);
   error = vnet_connect (&connect_args);
   SESSION_TEST ((error != 0), "client connect should return error code");
-  SESSION_TEST ((error == VNET_API_ERROR_SESSION_CONNECT),
-		"error code should be connect (not in same ns)");
+  SESSION_TEST ((error == SESSION_E_NOROUTE),
+		"error code should be noroute (not in same ns)");
   detach_args.app_index = client_index;
   vnet_application_detach (&detach_args);
 
@@ -1255,8 +1255,7 @@ session_test_rules (vlib_main_t * vm, unformat_input_t * input)
   /* Try connecting */
   error = vnet_connect (&connect_args);
   SESSION_TEST ((error != 0), "connect should fail");
-  SESSION_TEST ((error == VNET_API_ERROR_APP_CONNECT_FILTERED),
-		"connect should be filtered");
+  SESSION_TEST ((error == SESSION_E_FILTERED), "connect should be filtered");
 
   sep.ip.ip4.as_u32 -= 1 << 24;
 
@@ -1529,8 +1528,7 @@ session_test_rules (vlib_main_t * vm, unformat_input_t * input)
 
   error = vnet_connect (&connect_args);
   SESSION_TEST ((error != 0), "connect should fail");
-  SESSION_TEST ((error == VNET_API_ERROR_APP_CONNECT_FILTERED),
-		"connect should be filtered");
+  SESSION_TEST ((error == SESSION_E_FILTERED), "connect should be filtered");
 
   /*
    * Lookup test namespace
@@ -1542,8 +1540,7 @@ session_test_rules (vlib_main_t * vm, unformat_input_t * input)
   connect_args.app_index = server_index;
   error = vnet_connect (&connect_args);
   SESSION_TEST ((error != 0), "connect should fail");
-  SESSION_TEST ((error == VNET_API_ERROR_APP_CONNECT_FILTERED),
-		"connect should be filtered");
+  SESSION_TEST ((error == SESSION_E_FILTERED), "connect should be filtered");
 
   args.table_args.is_add = 0;
   vnet_session_rule_add_del (&args);
diff --git a/src/vcl/vcl_bapi.c b/src/vcl/vcl_bapi.c
index 077024ed2cf..4ec09089cd8 100644
--- a/src/vcl/vcl_bapi.c
+++ b/src/vcl/vcl_bapi.c
@@ -33,7 +33,7 @@
 #include <vpp/api/vpe_all_api_h.h>
 #undef vl_printfun
 
-u8 *
+static u8 *
 format_api_error (u8 * s, va_list * args)
 {
   i32 error = va_arg (*args, u32);
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index 38818d2d356..12af09fbf55 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -667,8 +667,6 @@ void vcl_segment_detach (u64 segment_handle);
 
 u32 vcl_max_nsid_len (void);
 
-u8 *format_api_error (u8 * s, va_list * args);
-
 void vls_init ();
 #endif /* SRC_VCL_VCL_PRIVATE_H_ */
 
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index ba1f1166556..9a19348cad4 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -445,7 +445,7 @@ vcl_session_connected_handler (vcl_worker_t * wrk,
   if (mp->retval)
     {
       VDBG (0, "ERROR: session index %u: connect failed! %U",
-	    session_index, format_api_error, ntohl (mp->retval));
+	    session_index, format_session_error, mp->retval);
       session->session_state = STATE_DETACHED | STATE_DISCONNECT;
       session->vpp_handle = mp->handle;
       return session_index;
@@ -565,7 +565,7 @@ vcl_session_bound_handler (vcl_worker_t * wrk, session_bound_msg_t * mp)
   if (mp->retval)
     {
       VERR ("session %u [0x%llx]: bind failed: %U", sid, mp->handle,
-	    format_api_error, mp->retval);
+	    format_session_error, mp->retval);
       if (session)
 	{
 	  session->session_state = STATE_DETACHED;
@@ -633,7 +633,7 @@ vcl_session_unlisten_reply_handler (vcl_worker_t * wrk, void *data)
 
   if (mp->retval)
     VDBG (0, "ERROR: session %u [0xllx]: unlisten failed: %U",
-	  s->session_index, mp->handle, format_api_error, ntohl (mp->retval));
+	  s->session_index, mp->handle, format_session_error, mp->retval);
 
   if (mp->context != wrk->wrk_index)
     VDBG (0, "wrong context");
diff --git a/src/vnet/session/application.c b/src/vnet/session/application.c
index 7923d2d050e..8d7c909ba67 100644
--- a/src/vnet/session/application.c
+++ b/src/vnet/session/application.c
@@ -1019,7 +1019,7 @@ vnet_connect (vnet_connect_args_t * a)
   ASSERT (vlib_thread_is_main_w_barrier ());
 
   if (session_endpoint_is_zero (&a->sep))
-    return VNET_API_ERROR_INVALID_VALUE;
+    return SESSION_E_INVALID_RMT_IP;
 
   client = application_get (a->app_index);
   session_endpoint_update_for_app (&a->sep_ext, client, 1 /* is_connect */ );
@@ -1039,13 +1039,12 @@ vnet_connect (vnet_connect_args_t * a)
       rv = app_worker_connect_session (client_wrk, &a->sep, a->api_context);
       if (rv <= 0)
 	return rv;
+      a->sep_ext.transport_proto = a->sep_ext.original_tp;
     }
   /*
    * Not connecting to a local server, propagate to transport
    */
-  if (app_worker_connect_session (client_wrk, &a->sep, a->api_context))
-    return VNET_API_ERROR_SESSION_CONNECT;
-  return 0;
+  return app_worker_connect_session (client_wrk, &a->sep, a->api_context);
 }
 
 int
diff --git a/src/vnet/session/application.h b/src/vnet/session/application.h
index 90b5a5a277e..00b60c33469 100644
--- a/src/vnet/session/application.h
+++ b/src/vnet/session/application.h
@@ -250,7 +250,7 @@ int app_worker_init_accepted (session_t * s);
 int app_worker_accept_notify (app_worker_t * app_wrk, session_t * s);
 int app_worker_init_connected (app_worker_t * app_wrk, session_t * s);
 int app_worker_connect_notify (app_worker_t * app_wrk, session_t * s,
-			       u32 opaque);
+			       session_error_t err, u32 opaque);
 int app_worker_close_notify (app_worker_t * app_wrk, session_t * s);
 int app_worker_transport_closed_notify (app_worker_t * app_wrk,
 					session_t * s);
@@ -299,7 +299,7 @@ app_cert_key_pair_t *app_cert_key_pair_get_default ();
 int mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
 			      session_handle_t handle, int rv);
 int mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
-				  session_t * s, u8 is_fail);
+				  session_t * s, session_error_t err);
 void mq_send_unlisten_reply (app_worker_t * app_wrk, session_handle_t sh,
 			     u32 context, int rv);
 
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index b1ab847073a..7d5d044cc5a 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -42,7 +42,7 @@ typedef struct session_cb_vft_
 
   /** Connection request callback */
   int (*session_connected_callback) (u32 app_wrk_index, u32 opaque,
-				     session_t * s, u8 code);
+				     session_t * s, session_error_t code);
 
   /** Notify app that session is closing */
   void (*session_disconnect_callback) (session_t * s);
@@ -741,6 +741,24 @@ app_recv (app_session_t * s, u8 * data, u32 len)
   return app_recv_stream (s, data, len);
 }
 
+/* *INDENT-OFF* */
+static char *session_error_str[] = {
+#define _(sym, str) str,
+    foreach_session_error
+#undef _
+};
+/* *INDENT-ON* */
+
+static inline u8 *
+format_session_error (u8 * s, va_list * args)
+{
+  session_error_t error = va_arg (*args, session_error_t);
+  if (-error >= 0 && -error < SESSION_N_ERRORS)
+    s = format (s, "%s", session_error_str[-error]);
+  else
+    s = format (s, "invalid session err %u", -error);
+  return s;
+}
 #endif /* __included_uri_h__ */
 
 /*
diff --git a/src/vnet/session/application_local.c b/src/vnet/session/application_local.c
index e2c1082d0b7..d54d1119ce6 100644
--- a/src/vnet/session/application_local.c
+++ b/src/vnet/session/application_local.c
@@ -96,7 +96,7 @@ ct_session_connect_notify (session_t * ss)
   segment_manager_t *sm;
   fifo_segment_t *seg;
   u64 segment_handle;
-  int is_fail = 0;
+  int err = 0;
   session_t *cs;
   u32 ss_index;
 
@@ -108,13 +108,12 @@ ct_session_connect_notify (session_t * ss)
   seg = segment_manager_get_segment_w_lock (sm, ss->rx_fifo->segment_index);
   segment_handle = segment_manager_segment_handle (sm, seg);
 
-  if (app_worker_add_segment_notify (client_wrk, segment_handle))
+  if ((err = app_worker_add_segment_notify (client_wrk, segment_handle)))
     {
       clib_warning ("failed to notify client %u of new segment",
 		    sct->client_wrk);
       segment_manager_segment_reader_unlock (sm);
       session_close (ss);
-      is_fail = 1;
     }
   else
     {
@@ -149,8 +148,7 @@ ct_session_connect_notify (session_t * ss)
       return -1;
     }
 
-  if (app_worker_connect_notify (client_wrk, is_fail ? 0 : cs,
-				 sct->client_opaque))
+  if (app_worker_connect_notify (client_wrk, cs, err, sct->client_opaque))
     {
       session_close (ss);
       return -1;
@@ -371,7 +369,7 @@ ct_session_connect (transport_endpoint_cfg_t * tep)
   table_index = application_local_session_table (app);
   lh = session_lookup_local_endpoint (table_index, sep);
   if (lh == SESSION_DROP_HANDLE)
-    return VNET_API_ERROR_APP_CONNECT_FILTERED;
+    return SESSION_E_FILTERED;
 
   if (lh == SESSION_INVALID_HANDLE)
     goto global_scope;
@@ -396,10 +394,10 @@ ct_session_connect (transport_endpoint_cfg_t * tep)
 
 global_scope:
   if (session_endpoint_is_local (sep))
-    return VNET_API_ERROR_SESSION_CONNECT;
+    return SESSION_E_NOROUTE;
 
   if (!application_has_global_scope (app))
-    return VNET_API_ERROR_APP_CONNECT_SCOPE;
+    return SESSION_E_SCOPE;
 
   fib_proto = session_endpoint_fib_proto (sep);
   table_index = session_lookup_get_index_for_fib (fib_proto, sep->fib_index);
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index 142b662b4d4..c17f43e90d1 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -173,7 +173,7 @@ app_worker_init_listener (app_worker_t * app_wrk, session_t * ls)
   /* Allocate segment manager. All sessions derived out of a listen session
    * have fifos allocated by the same segment manager. */
   if (!(sm = app_worker_alloc_segment_manager (app_wrk)))
-    return -1;
+    return SESSION_E_ALLOC;
 
   /* Keep track of the segment manager for the listener or this worker */
   hash_set (app_wrk->listeners_table, listen_session_get_handle (ls),
@@ -182,12 +182,8 @@ app_worker_init_listener (app_worker_t * app_wrk, session_t * ls)
   if (transport_connection_is_cless (session_get_transport (ls)))
     {
       if (ls->rx_fifo)
-	{
-	  clib_warning ("sharing of connectionless listeners not supported");
-	  return -1;
-	}
-      if (app_worker_alloc_session_fifos (sm, ls))
-	return -1;
+	return SESSION_E_NOSUPPORT;
+      return app_worker_alloc_session_fifos (sm, ls);
     }
   return 0;
 }
@@ -197,9 +193,10 @@ app_worker_start_listen (app_worker_t * app_wrk,
 			 app_listener_t * app_listener)
 {
   session_t *ls;
+  int rv;
 
   if (clib_bitmap_get (app_listener->workers, app_wrk->wrk_map_index))
-    return VNET_API_ERROR_ADDRESS_IN_USE;
+    return SESSION_E_ALREADY_LISTENING;
 
   app_listener->workers = clib_bitmap_set (app_listener->workers,
 					   app_wrk->wrk_map_index, 1);
@@ -207,15 +204,15 @@ app_worker_start_listen (app_worker_t * app_wrk,
   if (app_listener->session_index != SESSION_INVALID_INDEX)
     {
       ls = session_get (app_listener->session_index, 0);
-      if (app_worker_init_listener (app_wrk, ls))
-	return -1;
+      if ((rv = app_worker_init_listener (app_wrk, ls)))
+	return rv;
     }
 
   if (app_listener->local_index != SESSION_INVALID_INDEX)
     {
       ls = session_get (app_listener->local_index, 0);
-      if (app_worker_init_listener (app_wrk, ls))
-	return -1;
+      if ((rv = app_worker_init_listener (app_wrk, ls)))
+	return rv;
     }
 
   return 0;
@@ -321,8 +318,7 @@ app_worker_init_connected (app_worker_t * app_wrk, session_t * s)
   if (!application_is_builtin_proxy (app))
     {
       sm = app_worker_get_connect_segment_manager (app_wrk);
-      if (app_worker_alloc_session_fifos (sm, s))
-	return -1;
+      return app_worker_alloc_session_fifos (sm, s);
     }
 
   if (app->cb_fns.fifo_tuning_callback)
@@ -332,11 +328,12 @@ app_worker_init_connected (app_worker_t * app_wrk, session_t * s)
 }
 
 int
-app_worker_connect_notify (app_worker_t * app_wrk, session_t * s, u32 opaque)
+app_worker_connect_notify (app_worker_t * app_wrk, session_t * s,
+			   session_error_t err, u32 opaque)
 {
   application_t *app = application_get (app_wrk->app_index);
   return app->cb_fns.session_connected_callback (app_wrk->wrk_index, opaque,
-						 s, s == 0 /* is_fail */ );
+						 s, err);
 }
 
 int
diff --git a/src/vnet/session/segment_manager.c b/src/vnet/session/segment_manager.c
index ad5db656c77..154c7a61880 100644
--- a/src/vnet/session/segment_manager.c
+++ b/src/vnet/session/segment_manager.c
@@ -664,12 +664,12 @@ alloc_check:
 	{
 	  clib_warning ("Added a segment, still can't allocate a fifo");
 	  segment_manager_segment_reader_unlock (sm);
-	  return SESSION_ERROR_NEW_SEG_NO_SPACE;
+	  return SESSION_E_SEG_NO_SPACE2;
 	}
       if ((new_fs_index = segment_manager_add_segment (sm, 0)) < 0)
 	{
 	  clib_warning ("Failed to add new segment");
-	  return SESSION_ERROR_SEG_CREATE;
+	  return SESSION_E_SEG_CREATE;
 	}
       fs = segment_manager_get_segment_w_lock (sm, new_fs_index);
       alloc_fail = segment_manager_try_alloc_fifos (fs, thread_index,
@@ -682,7 +682,7 @@ alloc_check:
   else
     {
       clib_warning ("Can't add new seg and no space to allocate fifos!");
-      return SESSION_ERROR_NO_SPACE;
+      return SESSION_E_SEG_NO_SPACE;
     }
 }
 
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index 33514008dd0..ac29627548c 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -736,7 +736,8 @@ session_main_flush_all_enqueue_events (u8 transport_proto)
 }
 
 static inline int
-session_stream_connect_notify_inline (transport_connection_t * tc, u8 is_fail,
+session_stream_connect_notify_inline (transport_connection_t * tc,
+				      session_error_t err,
 				      session_state_t opened_state)
 {
   u32 opaque = 0, new_ti, new_si;
@@ -764,8 +765,8 @@ session_stream_connect_notify_inline (transport_connection_t * tc, u8 is_fail,
 
   opaque = tc->s_index;
 
-  if (is_fail)
-    return app_worker_connect_notify (app_wrk, s, opaque);
+  if (err)
+    return app_worker_connect_notify (app_wrk, s, err, opaque);
 
   s = session_alloc_for_connection (tc);
   s->session_state = SESSION_STATE_CONNECTING;
@@ -773,10 +774,10 @@ session_stream_connect_notify_inline (transport_connection_t * tc, u8 is_fail,
   new_si = s->session_index;
   new_ti = s->thread_index;
 
-  if (app_worker_init_connected (app_wrk, s))
+  if ((err = app_worker_init_connected (app_wrk, s)))
     {
       session_free (s);
-      app_worker_connect_notify (app_wrk, 0, opaque);
+      app_worker_connect_notify (app_wrk, 0, err, opaque);
       return -1;
     }
 
@@ -784,7 +785,7 @@ session_stream_connect_notify_inline (transport_connection_t * tc, u8 is_fail,
   s->session_state = opened_state;
   session_lookup_add_connection (tc, session_handle (s));
 
-  if (app_worker_connect_notify (app_wrk, s, opaque))
+  if (app_worker_connect_notify (app_wrk, s, SESSION_E_NONE, opaque))
     {
       s = session_get (new_si, new_ti);
       session_free_w_fifos (s);
@@ -795,17 +796,17 @@ session_stream_connect_notify_inline (transport_connection_t * tc, u8 is_fail,
 }
 
 int
-session_stream_connect_notify (transport_connection_t * tc, u8 is_fail)
+session_stream_connect_notify (transport_connection_t * tc,
+			       session_error_t err)
 {
-  return session_stream_connect_notify_inline (tc, is_fail,
-					       SESSION_STATE_READY);
+  return session_stream_connect_notify_inline (tc, err, SESSION_STATE_READY);
 }
 
 int
-session_ho_stream_connect_notify (transport_connection_t * tc, u8 is_fail)
+session_ho_stream_connect_notify (transport_connection_t * tc,
+				  session_error_t err)
 {
-  return session_stream_connect_notify_inline (tc, is_fail,
-					       SESSION_STATE_OPENED);
+  return session_stream_connect_notify_inline (tc, err, SESSION_STATE_OPENED);
 }
 
 typedef struct _session_switch_pool_args
@@ -1116,7 +1117,7 @@ session_open_cl (u32 app_wrk_index, session_endpoint_t * rmt, u32 opaque)
 
   sh = session_handle (s);
   session_lookup_add_connection (tc, sh);
-  return app_worker_connect_notify (app_wrk, s, opaque);
+  return app_worker_connect_notify (app_wrk, s, SESSION_E_NONE, opaque);
 }
 
 int
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index 681b42d868d..a9f965d8f62 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -30,9 +30,6 @@ _(NOT_READY, "Session not ready packets")                               \
 _(FIFO_FULL, "Packets dropped for lack of rx fifo space")               \
 _(EVENT_FIFO_FULL, "Events not sent for lack of event fifo space")      \
 _(API_QUEUE_FULL, "Sessions not created for lack of API queue space")   \
-_(NEW_SEG_NO_SPACE, "Created segment, couldn't allocate a fifo pair")   \
-_(NO_SPACE, "Couldn't allocate a fifo pair")				\
-_(SEG_CREATE, "Couldn't create a new segment")
 
 typedef enum
 {
@@ -40,7 +37,7 @@ typedef enum
   foreach_session_input_error
 #undef _
     SESSION_N_ERROR,
-} session_error_t;
+} session_input_error_t;
 
 typedef struct session_tx_context_
 {
@@ -456,7 +453,8 @@ int session_enqueue_dgram_connection (session_t * s,
 				      session_dgram_hdr_t * hdr,
 				      vlib_buffer_t * b, u8 proto,
 				      u8 queue_event);
-int session_stream_connect_notify (transport_connection_t * tc, u8 is_fail);
+int session_stream_connect_notify (transport_connection_t * tc,
+				   session_error_t err);
 int session_dgram_connect_notify (transport_connection_t * tc,
 				  u32 old_thread_index,
 				  session_t ** new_session);
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index 6dcf06bd724..43ecf2b07e9 100644
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -100,15 +100,12 @@ session_send_fds (vl_api_registration_t * reg, int fds[], int n_fds)
 {
   clib_error_t *error;
   if (vl_api_registration_file_index (reg) == VL_API_INVALID_FI)
-    {
-      clib_warning ("can't send memfd fd");
-      return -1;
-    }
+    return SESSION_E_BAPI_NO_FD;
   error = vl_api_send_fd_msg (reg, fds, n_fds);
   if (error)
     {
       clib_error_report (error);
-      return -1;
+      return SESSION_E_BAPI_SEND_FD;
     }
   return 0;
 }
@@ -146,7 +143,7 @@ mq_send_session_accepted_cb (session_t * s)
   app = application_get (app_wrk->app_index);
   app_mq = app_wrk->event_queue;
   if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return -1;
+    return SESSION_E_MQ_MSG_ALLOC;
 
   evt = svm_msg_q_msg_data (app_mq, msg);
   clib_memset (evt, 0, sizeof (*evt));
@@ -265,7 +262,7 @@ mq_send_session_reset_cb (session_t * s)
 
 int
 mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
-			      session_t * s, u8 is_fail)
+			      session_t * s, session_error_t err)
 {
   svm_msg_q_msg_t _msg, *msg = &_msg;
   session_connected_msg_t *mp;
@@ -284,7 +281,7 @@ mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
     }
 
   if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return -1;
+    return SESSION_E_MQ_MSG_ALLOC;
 
   evt = svm_msg_q_msg_data (app_mq, msg);
   clib_memset (evt, 0, sizeof (*evt));
@@ -293,7 +290,7 @@ mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
   clib_memset (mp, 0, sizeof (*mp));
   mp->context = api_context;
 
-  if (is_fail)
+  if (err)
     goto done;
 
   if (session_has_transport (s))
@@ -301,7 +298,8 @@ mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
       tc = session_get_transport (s);
       if (!tc)
 	{
-	  is_fail = 1;
+	  clib_warning ("failed to retrieve transport!");
+	  err = SESSION_E_REFUSED;
 	  goto done;
 	}
 
@@ -336,8 +334,7 @@ mq_send_session_connected_cb (u32 app_wrk_index, u32 api_context,
     }
 
 done:
-  mp->retval = is_fail ?
-    clib_host_to_net_u32 (VNET_API_ERROR_SESSION_CONNECT) : 0;
+  mp->retval = err;
 
   svm_msg_q_add_and_unlock (app_mq, msg);
   return 0;
@@ -365,7 +362,7 @@ mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
     }
 
   if (mq_try_lock_and_alloc_msg (app_mq, msg))
-    return -1;
+    return SESSION_E_MQ_MSG_ALLOC;
 
   evt = svm_msg_q_msg_data (app_mq, msg);
   clib_memset (evt, 0, sizeof (*evt));
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index 0290fe69544..c2a6ec921af 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -139,8 +139,7 @@ session_mq_connect_handler (void *data)
     {
       clib_warning ("connect returned: %U", format_vnet_api_errno, rv);
       app_wrk = application_get_worker (app, mp->wrk_index);
-      mq_send_session_connected_cb (app_wrk->wrk_index, mp->context, 0,
-				    /* is_fail */ 1);
+      mq_send_session_connected_cb (app_wrk->wrk_index, mp->context, 0, rv);
     }
 
   vec_free (a->sep_ext.hostname);
@@ -169,8 +168,7 @@ session_mq_connect_uri_handler (void *data)
     {
       clib_warning ("connect_uri returned: %d", rv);
       app_wrk = application_get_worker (app, 0 /* default wrk only */ );
-      mq_send_session_connected_cb (app_wrk->wrk_index, mp->context, 0,
-				    /* is_fail */ 1);
+      mq_send_session_connected_cb (app_wrk->wrk_index, mp->context, 0, rv);
     }
 }
 
diff --git a/src/vnet/session/session_types.h b/src/vnet/session/session_types.h
index a0360136b1d..ca5dcc1c123 100644
--- a/src/vnet/session/session_types.h
+++ b/src/vnet/session/session_types.h
@@ -433,6 +433,53 @@ typedef struct session_dgram_header_
 
 STATIC_ASSERT (sizeof (session_dgram_hdr_t) == (SESSION_CONN_ID_LEN + 8),
 	       "session conn id wrong length");
+
+#define foreach_session_error						\
+  _(NONE, "no error")							\
+  _(UNKNOWN, "generic/unknown error")					\
+  _(REFUSED, "refused")							\
+  _(TIMEDOUT, "timedout")						\
+  _(ALLOC, "obj/memory allocation error")				\
+  _(NOROUTE, "no route")						\
+  _(NOINTF, "no resolving interface")					\
+  _(NOIP, "no ip for lcl interface")					\
+  _(NOPORT, "no lcl port")						\
+  _(NOSUPPORT, "not supported")						\
+  _(PORTINUSE, "lcl port in use")					\
+  _(IPINUSE, "ip in use")						\
+  _(ALREADY_LISTENING, "ip port pair already listened on")		\
+  _(INVALID_RMT_IP, "invalid remote ip")				\
+  _(SEG_NO_SPACE, "Couldn't allocate a fifo pair")			\
+  _(SEG_NO_SPACE2, "Created segment, couldn't allocate a fifo pair") 	\
+  _(SEG_CREATE, "Couldn't create a new segment")			\
+  _(FILTERED, "session filtered")					\
+  _(SCOPE, "scope not supported")					\
+  _(BAPI_NO_FD, "bapi doesn't have a socket fd")			\
+  _(BAPI_SEND_FD, "couldn't send fd over bapi socket fd")		\
+  _(BAPI_NO_REG, "app bapi registration not found")			\
+  _(MQ_MSG_ALLOC, "failed to alloc mq msg")				\
+  _(TLS_HANDSHAKE, "failed tls handshake")				\
+
+typedef enum session_error_p_
+{
+#define _(sym, str) SESSION_EP_##sym,
+  foreach_session_error
+#undef _
+  SESSION_N_ERRORS
+} session_error_p_t;
+
+typedef enum session_error_
+{
+#define _(sym, str) SESSION_E_##sym = -SESSION_EP_##sym,
+  foreach_session_error
+#undef _
+} session_error_t;
+
+/* Maintained for compatibility. Will be deprecated */
+#define SESSION_ERROR_SEG_CREATE SESSION_E_SEG_CREATE
+#define SESSION_ERROR_NO_SPACE SESSION_E_SEG_NO_SPACE
+#define SESSION_ERROR_NEW_SEG_NO_SPACE SESSION_E_SEG_NO_SPACE2
+
 #endif /* SRC_VNET_SESSION_SESSION_TYPES_H_ */
 
 /*
diff --git a/src/vnet/session/transport.c b/src/vnet/session/transport.c
index 69046855c38..29c94f363ff 100644
--- a/src/vnet/session/transport.c
+++ b/src/vnet/session/transport.c
@@ -480,7 +480,7 @@ transport_alloc_local_port (u8 proto, ip46_address_t * ip)
   return -1;
 }
 
-static clib_error_t *
+static session_error_t
 transport_get_interface_ip (u32 sw_if_index, u8 is_ip4, ip46_address_t * addr)
 {
   if (is_ip4)
@@ -488,9 +488,7 @@ transport_get_interface_ip (u32 sw_if_index, u8 is_ip4, ip46_address_t * addr)
       ip4_address_t *ip4;
       ip4 = ip_interface_get_first_ip (sw_if_index, 1);
       if (!ip4)
-	return clib_error_return (0, "no routable ip4 address on %U",
-				  format_vnet_sw_if_index_name,
-				  vnet_get_main (), sw_if_index);
+	return SESSION_E_NOIP;
       addr->ip4.as_u32 = ip4->as_u32;
     }
   else
@@ -498,15 +496,13 @@ transport_get_interface_ip (u32 sw_if_index, u8 is_ip4, ip46_address_t * addr)
       ip6_address_t *ip6;
       ip6 = ip_interface_get_first_ip (sw_if_index, 0);
       if (ip6 == 0)
-	return clib_error_return (0, "no routable ip6 addresses on %U",
-				  format_vnet_sw_if_index_name,
-				  vnet_get_main (), sw_if_index);
+	return SESSION_E_NOIP;
       clib_memcpy_fast (&addr->ip6, ip6, sizeof (*ip6));
     }
   return 0;
 }
 
-static clib_error_t *
+static session_error_t
 transport_find_local_ip_for_remote (u32 sw_if_index,
 				    transport_endpoint_t * rmt,
 				    ip46_address_t * lcl_addr)
@@ -526,14 +522,11 @@ transport_find_local_ip_for_remote (u32 sw_if_index,
 
       /* Couldn't find route to destination. Bail out. */
       if (fei == FIB_NODE_INDEX_INVALID)
-	return clib_error_return (0, "no route to %U", format_ip46_address,
-				  &rmt->ip, (rmt->is_ip4 == 0) + 1);
+	return SESSION_E_NOROUTE;
 
       sw_if_index = fib_entry_get_resolving_interface (fei);
       if (sw_if_index == ENDPOINT_INVALID_INDEX)
-	return clib_error_return (0, "no resolving interface for %U",
-				  format_ip46_address, &rmt->ip,
-				  (rmt->is_ip4 == 0) + 1);
+	return SESSION_E_NOINTF;
     }
 
   clib_memset (lcl_addr, 0, sizeof (*lcl_addr));
@@ -545,7 +538,7 @@ transport_alloc_local_endpoint (u8 proto, transport_endpoint_cfg_t * rmt_cfg,
 				ip46_address_t * lcl_addr, u16 * lcl_port)
 {
   transport_endpoint_t *rmt = (transport_endpoint_t *) rmt_cfg;
-  clib_error_t *error;
+  session_error_t error;
   int port;
   u32 tei;
 
@@ -557,10 +550,7 @@ transport_alloc_local_endpoint (u8 proto, transport_endpoint_cfg_t * rmt_cfg,
       error = transport_find_local_ip_for_remote (rmt_cfg->peer.sw_if_index,
 						  rmt, lcl_addr);
       if (error)
-	{
-	  clib_error_report (error);
-	  return -1;
-	}
+	return error;
     }
   else
     {
@@ -576,10 +566,7 @@ transport_alloc_local_endpoint (u8 proto, transport_endpoint_cfg_t * rmt_cfg,
     {
       port = transport_alloc_local_port (proto, lcl_addr);
       if (port < 1)
-	{
-	  clib_warning ("Failed to allocate src port");
-	  return -1;
-	}
+	return SESSION_E_NOPORT;
       *lcl_port = port;
     }
   else
@@ -588,7 +575,7 @@ transport_alloc_local_endpoint (u8 proto, transport_endpoint_cfg_t * rmt_cfg,
       tei = transport_endpoint_lookup (&local_endpoints_table, proto,
 				       lcl_addr, port);
       if (tei != ENDPOINT_INVALID_INDEX)
-	return -1;
+	return SESSION_E_PORTINUSE;
 
       transport_endpoint_mark_used (proto, lcl_addr, port);
       *lcl_port = port;
diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index d85225b9172..b1ae37409fd 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -738,10 +738,7 @@ tcp_alloc_custom_local_endpoint (tcp_main_t * tm, ip46_address_t * lcl_addr,
     }
   port = transport_alloc_local_port (TRANSPORT_PROTO_TCP, lcl_addr);
   if (port < 1)
-    {
-      clib_warning ("Failed to allocate src port");
-      return -1;
-    }
+    return SESSION_E_NOPORT;
   *lcl_port = port;
   return 0;
 }
@@ -767,7 +764,7 @@ tcp_session_open (transport_endpoint_cfg_t * rmt)
 					 rmt, &lcl_addr, &lcl_port);
 
   if (rv)
-    return -1;
+    return rv;
 
   /*
    * Create connection and send SYN
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 713e11fd896..403acad1700 100755
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -1985,7 +1985,8 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 
 	  /* Notify app that we have connection. If session layer can't
 	   * allocate session send reset */
-	  if (session_stream_connect_notify (&new_tc0->connection, 0))
+	  if (session_stream_connect_notify (&new_tc0->connection,
+					     SESSION_E_NONE))
 	    {
 	      tcp_send_reset_w_pkt (new_tc0, b0, my_thread_index, is_ip4);
 	      tcp_connection_cleanup (new_tc0);
@@ -2006,7 +2007,8 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 	  new_tc0->state = TCP_STATE_SYN_RCVD;
 
 	  /* Notify app that we have connection */
-	  if (session_stream_connect_notify (&new_tc0->connection, 0))
+	  if (session_stream_connect_notify (&new_tc0->connection,
+					     SESSION_E_NONE))
 	    {
 	      tcp_connection_cleanup (new_tc0);
 	      tcp_send_reset_w_pkt (tc0, b0, my_thread_index, is_ip4);
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index a68d5269abd..095f3602557 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1472,7 +1472,7 @@ tcp_timer_retransmit_syn_handler (tcp_connection_t * tc)
   /* Active open establish timeout */
   if (tc->rto >= TCP_ESTABLISH_TIME >> 1)
     {
-      session_stream_connect_notify (&tc->connection, 1 /* fail */ );
+      session_stream_connect_notify (&tc->connection, SESSION_E_TIMEDOUT);
       tcp_connection_cleanup (tc);
       return;
     }
diff --git a/src/vnet/tls/tls.c b/src/vnet/tls/tls.c
index 88ce3591bb6..7a172b88928 100644
--- a/src/vnet/tls/tls.c
+++ b/src/vnet/tls/tls.c
@@ -217,7 +217,7 @@ tls_notify_app_accept (tls_ctx_t * ctx)
 }
 
 int
-tls_notify_app_connected (tls_ctx_t * ctx, u8 is_failed)
+tls_notify_app_connected (tls_ctx_t * ctx, session_error_t err)
 {
   session_t *app_session;
   app_worker_t *app_wrk;
@@ -229,7 +229,7 @@ tls_notify_app_connected (tls_ctx_t * ctx, u8 is_failed)
       return -1;
     }
 
-  if (is_failed)
+  if (err)
     goto failed;
 
   app_session = session_get (ctx->c_s_index, ctx->c_thread_index);
@@ -238,12 +238,12 @@ tls_notify_app_connected (tls_ctx_t * ctx, u8 is_failed)
   app_session->session_type =
     session_type_from_proto_and_ip (TRANSPORT_PROTO_TLS, ctx->tcp_is_ip4);
 
-  if (app_worker_init_connected (app_wrk, app_session))
+  if ((err = app_worker_init_connected (app_wrk, app_session)))
     goto failed;
 
   app_session->session_state = SESSION_STATE_CONNECTING;
   if (app_worker_connect_notify (app_wrk, app_session,
-				 ctx->parent_app_api_context))
+				 SESSION_E_NONE, ctx->parent_app_api_context))
     {
       TLS_DBG (1, "failed to notify app");
       tls_disconnect (ctx->tls_ctx_handle, vlib_get_thread_index ());
@@ -260,7 +260,8 @@ failed:
   session_free (session_get (ctx->c_s_index, ctx->c_thread_index));
   ctx->no_app_session = 1;
   tls_disconnect (ctx->tls_ctx_handle, vlib_get_thread_index ());
-  return app_worker_connect_notify (app_wrk, 0, ctx->parent_app_api_context);
+  return app_worker_connect_notify (app_wrk, 0, err,
+				    ctx->parent_app_api_context);
 }
 
 static inline void
@@ -452,7 +453,7 @@ tls_app_rx_callback (session_t * tls_session)
 
 int
 tls_session_connected_callback (u32 tls_app_index, u32 ho_ctx_index,
-				session_t * tls_session, u8 is_fail)
+				session_t * tls_session, session_error_t err)
 {
   session_t *app_session;
   tls_ctx_t *ho_ctx, *ctx;
@@ -460,7 +461,7 @@ tls_session_connected_callback (u32 tls_app_index, u32 ho_ctx_index,
 
   ho_ctx = tls_ctx_half_open_get (ho_ctx_index);
 
-  if (is_fail)
+  if (err)
     {
       app_worker_t *app_wrk;
       u32 api_context;
@@ -470,7 +471,7 @@ tls_session_connected_callback (u32 tls_app_index, u32 ho_ctx_index,
       if (app_wrk)
 	{
 	  api_context = ho_ctx->c_s_index;
-	  app_worker_connect_notify (app_wrk, 0, api_context);
+	  app_worker_connect_notify (app_wrk, 0, err, api_context);
 	}
       tls_ctx_half_open_reader_unlock ();
       tls_ctx_half_open_free (ho_ctx_index);
diff --git a/src/vnet/tls/tls.h b/src/vnet/tls/tls.h
index 15d06db6563..1281e3d62c9 100644
--- a/src/vnet/tls/tls.h
+++ b/src/vnet/tls/tls.h
@@ -126,7 +126,7 @@ int tls_add_vpp_q_tx_evt (session_t * s);
 int tls_add_vpp_q_builtin_tx_evt (session_t * s);
 int tls_add_vpp_q_builtin_rx_evt (session_t * s);
 int tls_notify_app_accept (tls_ctx_t * ctx);
-int tls_notify_app_connected (tls_ctx_t * ctx, u8 is_failed);
+int tls_notify_app_connected (tls_ctx_t * ctx, session_error_t err);
 void tls_notify_app_enqueue (tls_ctx_t * ctx, session_t * app_session);
 void tls_disconnect_transport (tls_ctx_t * ctx);
 #endif /* SRC_VNET_TLS_TLS_H_ */
diff --git a/src/vnet/udp/udp.c b/src/vnet/udp/udp.c
index 3632204f863..65d50fff395 100644
--- a/src/vnet/udp/udp.c
+++ b/src/vnet/udp/udp.c
@@ -418,16 +418,18 @@ udp_open_connection (transport_endpoint_cfg_t * rmt)
   udp_connection_t *uc;
   ip46_address_t lcl_addr;
   u16 lcl_port;
+  int rv;
 
-  if (transport_alloc_local_endpoint (TRANSPORT_PROTO_UDP, rmt, &lcl_addr,
-				      &lcl_port))
-    return -1;
+  rv = transport_alloc_local_endpoint (TRANSPORT_PROTO_UDP, rmt, &lcl_addr,
+				       &lcl_port);
+  if (rv)
+    return rv;
 
   if (udp_is_valid_dst_port (lcl_port, rmt->is_ip4))
     {
       /* If specific source port was requested abort */
       if (rmt->peer.port)
-	return -1;
+	return SESSION_E_PORTINUSE;
 
       /* Try to find a port that's not used */
       while (udp_is_valid_dst_port (lcl_port, rmt->is_ip4))
@@ -435,10 +437,7 @@ udp_open_connection (transport_endpoint_cfg_t * rmt)
 	  lcl_port = transport_alloc_local_port (TRANSPORT_PROTO_UDP,
 						 &lcl_addr);
 	  if (lcl_port < 1)
-	    {
-	      clib_warning ("Failed to allocate src port");
-	      return -1;
-	    }
+	    return SESSION_E_PORTINUSE;
 	}
     }