13 files changed, 354 insertions, 207 deletions

diff --git a/src/plugins/hs_apps/sapi/vpp_echo.c b/src/plugins/hs_apps/sapi/vpp_echo.c
index 84089c6b512..0550006f949 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo.c
+++ b/src/plugins/hs_apps/sapi/vpp_echo.c
@@ -531,6 +531,21 @@ session_bound_handler (session_bound_msg_t * mp)
     em->proto_cb_vft->bound_uri_cb (mp, listen_session);
 }
 
+static int
+echo_segment_is_not_mapped (u64 segment_handle)
+{
+  echo_main_t *em = &echo_main;
+  uword *segment_present;
+  ECHO_LOG (3, "Check if segment mapped 0x%lx...", segment_handle);
+  clib_spinlock_lock (&em->segment_handles_lock);
+  segment_present = hash_get (em->shared_segment_handles, segment_handle);
+  clib_spinlock_unlock (&em->segment_handles_lock);
+  if (segment_present != 0)
+    return 0;
+  ECHO_LOG (2, "Segment not mapped (0x%lx)", segment_handle);
+  return -1;
+}
+
 static void
 session_accepted_handler (session_accepted_msg_t * mp)
 {
@@ -546,7 +561,7 @@ session_accepted_handler (session_accepted_msg_t * mp)
 		 "Unknown listener handle 0x%lx", mp->listener_handle);
       return;
     }
-  if (wait_for_segment_allocation (mp->segment_handle))
+  if (echo_segment_is_not_mapped (mp->segment_handle))
     {
       ECHO_FAIL (ECHO_FAIL_ACCEPTED_WAIT_FOR_SEG_ALLOC,
 		 "accepted wait_for_segment_allocation errored");
@@ -615,7 +630,7 @@ session_connected_handler (session_connected_msg_t * mp)
     }
 
   session = echo_session_new (em);
-  if (wait_for_segment_allocation (mp->segment_handle))
+  if (echo_segment_is_not_mapped (mp->segment_handle))
     {
       ECHO_FAIL (ECHO_FAIL_CONNECTED_WAIT_FOR_SEG_ALLOC,
 		 "connected wait_for_segment_allocation errored");
@@ -709,6 +724,66 @@ session_reset_handler (session_reset_msg_t * mp)
 }
 
 static void
+add_segment_handler (session_app_add_segment_msg_t * mp)
+{
+  fifo_segment_main_t *sm = &echo_main.segment_main;
+  fifo_segment_create_args_t _a, *a = &_a;
+  echo_main_t *em = &echo_main;
+  int *fds = 0, i;
+  char *seg_name = (char *) mp->segment_name;
+  u64 segment_handle = mp->segment_handle;
+
+  if (mp->fd_flags & SESSION_FD_F_MEMFD_SEGMENT)
+    {
+      vec_validate (fds, 1);
+      if (vl_socket_client_recv_fd_msg (fds, 1, 5))
+	{
+	  ECHO_FAIL (ECHO_FAIL_VL_API_RECV_FD_MSG,
+		     "vl_socket_client_recv_fd_msg failed");
+	  goto failed;
+	}
+
+      if (echo_ssvm_segment_attach (seg_name, SSVM_SEGMENT_MEMFD, fds[0]))
+	{
+	  ECHO_FAIL (ECHO_FAIL_VL_API_SVM_FIFO_SEG_ATTACH,
+		     "svm_fifo_segment_attach ('%s') "
+		     "failed on SSVM_SEGMENT_MEMFD", seg_name);
+	  goto failed;
+	}
+      vec_free (fds);
+    }
+  else
+    {
+      clib_memset (a, 0, sizeof (*a));
+      a->segment_name = seg_name;
+      a->segment_size = mp->segment_size;
+      /* Attach to the segment vpp created */
+      if (fifo_segment_attach (sm, a))
+	{
+	  ECHO_FAIL (ECHO_FAIL_VL_API_FIFO_SEG_ATTACH,
+		     "fifo_segment_attach ('%s') failed", seg_name);
+	  goto failed;
+	}
+    }
+  echo_segment_handle_add_del (em, segment_handle, 1 /* add */ );
+  ECHO_LOG (2, "Mapped segment 0x%lx", segment_handle);
+  return;
+
+failed:
+  for (i = 0; i < vec_len (fds); i++)
+    close (fds[i]);
+  vec_free (fds);
+}
+
+static void
+del_segment_handler (session_app_del_segment_msg_t * mp)
+{
+  echo_main_t *em = &echo_main;
+  echo_segment_handle_add_del (em, mp->segment_handle, 0 /* add */ );
+  ECHO_LOG (2, "Unmaped segment 0x%lx", mp->segment_handle);
+}
+
+static void
 handle_mq_event (session_event_t * e)
 {
   switch (e->event_type)
@@ -727,6 +802,12 @@ handle_mq_event (session_event_t * e)
     case SESSION_CTRL_EVT_UNLISTEN_REPLY:
       return session_unlisten_handler ((session_unlisten_reply_msg_t *)
 				       e->data);
+    case SESSION_CTRL_EVT_APP_ADD_SEGMENT:
+      add_segment_handler ((session_app_add_segment_msg_t *) e->data);
+      break;
+    case SESSION_CTRL_EVT_APP_DEL_SEGMENT:
+      del_segment_handler ((session_app_del_segment_msg_t *) e->data);
+      break;
     case SESSION_IO_EVT_RX:
       break;
     default:
diff --git a/src/plugins/hs_apps/sapi/vpp_echo_bapi.c b/src/plugins/hs_apps/sapi/vpp_echo_bapi.c
index 04eba24156c..cff331a1482 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo_bapi.c
+++ b/src/plugins/hs_apps/sapi/vpp_echo_bapi.c
@@ -198,8 +198,8 @@ echo_send_disconnect_session (echo_main_t * em, void *args)
  *
  */
 
-static int
-ssvm_segment_attach (char *name, ssvm_segment_type_t type, int fd)
+int
+echo_ssvm_segment_attach (char *name, ssvm_segment_type_t type, int fd)
 {
   fifo_segment_create_args_t _a, *a = &_a;
   fifo_segment_main_t *sm = &echo_main.segment_main;
@@ -218,7 +218,7 @@ ssvm_segment_attach (char *name, ssvm_segment_type_t type, int fd)
   return 0;
 }
 
-static inline void
+void
 echo_segment_handle_add_del (echo_main_t * em, u64 segment_handle, u8 add)
 {
   clib_spinlock_lock (&em->segment_handles_lock);
@@ -315,7 +315,7 @@ vl_api_app_attach_reply_t_handler (vl_api_app_attach_reply_t * mp)
 	}
 
       if (mp->fd_flags & SESSION_FD_F_VPP_MQ_SEGMENT)
-	if (ssvm_segment_attach (0, SSVM_SEGMENT_MEMFD, fds[n_fds++]))
+	if (echo_ssvm_segment_attach (0, SSVM_SEGMENT_MEMFD, fds[n_fds++]))
 	  {
 	    ECHO_FAIL (ECHO_FAIL_VL_API_SVM_FIFO_SEG_ATTACH,
 		       "svm_fifo_segment_attach failed on SSVM_SEGMENT_MEMFD");
@@ -323,8 +323,8 @@ vl_api_app_attach_reply_t_handler (vl_api_app_attach_reply_t * mp)
 	  }
 
       if (mp->fd_flags & SESSION_FD_F_MEMFD_SEGMENT)
-	if (ssvm_segment_attach ((char *) mp->segment_name,
-				 SSVM_SEGMENT_MEMFD, fds[n_fds++]))
+	if (echo_ssvm_segment_attach ((char *) mp->segment_name,
+				      SSVM_SEGMENT_MEMFD, fds[n_fds++]))
 	  {
 	    ECHO_FAIL (ECHO_FAIL_VL_API_SVM_FIFO_SEG_ATTACH,
 		       "svm_fifo_segment_attach ('%s') "
@@ -338,8 +338,8 @@ vl_api_app_attach_reply_t_handler (vl_api_app_attach_reply_t * mp)
     }
   else
     {
-      if (ssvm_segment_attach ((char *) mp->segment_name, SSVM_SEGMENT_SHM,
-			       -1))
+      if (echo_ssvm_segment_attach
+	  ((char *) mp->segment_name, SSVM_SEGMENT_SHM, -1))
 	{
 	  ECHO_FAIL (ECHO_FAIL_VL_API_SVM_FIFO_SEG_ATTACH,
 		     "svm_fifo_segment_attach ('%s') "
@@ -371,74 +371,11 @@ vl_api_application_detach_reply_t_handler (vl_api_application_detach_reply_t *
   echo_main.state = STATE_DETACHED;
 }
 
-static void
-vl_api_unmap_segment_t_handler (vl_api_unmap_segment_t * mp)
-{
-  echo_main_t *em = &echo_main;
-  u64 segment_handle = clib_net_to_host_u64 (mp->segment_handle);
-  echo_segment_handle_add_del (em, segment_handle, 0 /* add */ );
-  ECHO_LOG (2, "Unmaped segment 0x%lx", segment_handle);
-}
-
-static void
-vl_api_map_another_segment_t_handler (vl_api_map_another_segment_t * mp)
-{
-  fifo_segment_main_t *sm = &echo_main.segment_main;
-  fifo_segment_create_args_t _a, *a = &_a;
-  echo_main_t *em = &echo_main;
-  int *fds = 0, i;
-  char *seg_name = (char *) mp->segment_name;
-  u64 segment_handle = clib_net_to_host_u64 (mp->segment_handle);
-
-  if (mp->fd_flags & SESSION_FD_F_MEMFD_SEGMENT)
-    {
-      vec_validate (fds, 1);
-      if (vl_socket_client_recv_fd_msg (fds, 1, 5))
-	{
-	  ECHO_FAIL (ECHO_FAIL_VL_API_RECV_FD_MSG,
-		     "vl_socket_client_recv_fd_msg failed");
-	  goto failed;
-	}
-
-      if (ssvm_segment_attach (seg_name, SSVM_SEGMENT_MEMFD, fds[0]))
-	{
-	  ECHO_FAIL (ECHO_FAIL_VL_API_SVM_FIFO_SEG_ATTACH,
-		     "svm_fifo_segment_attach ('%s') "
-		     "failed on SSVM_SEGMENT_MEMFD", seg_name);
-	  goto failed;
-	}
-      vec_free (fds);
-    }
-  else
-    {
-      clib_memset (a, 0, sizeof (*a));
-      a->segment_name = seg_name;
-      a->segment_size = mp->segment_size;
-      /* Attach to the segment vpp created */
-      if (fifo_segment_attach (sm, a))
-	{
-	  ECHO_FAIL (ECHO_FAIL_VL_API_FIFO_SEG_ATTACH,
-		     "fifo_segment_attach ('%s') failed", seg_name);
-	  goto failed;
-	}
-    }
-  echo_segment_handle_add_del (em, segment_handle, 1 /* add */ );
-  ECHO_LOG (2, "Mapped segment 0x%lx", segment_handle);
-  return;
-
-failed:
-  for (i = 0; i < vec_len (fds); i++)
-    close (fds[i]);
-  vec_free (fds);
-}
-
 #define foreach_quic_echo_msg                                    \
 _(APP_ATTACH_REPLY, app_attach_reply)                            \
 _(APPLICATION_DETACH_REPLY, application_detach_reply)            \
-_(MAP_ANOTHER_SEGMENT, map_another_segment)                      \
 _(APP_ADD_CERT_KEY_PAIR_REPLY, app_add_cert_key_pair_reply)      \
-_(APP_DEL_CERT_KEY_PAIR_REPLY, app_del_cert_key_pair_reply)      \
-_(UNMAP_SEGMENT, unmap_segment)
+_(APP_DEL_CERT_KEY_PAIR_REPLY, app_del_cert_key_pair_reply)
 
 void
 echo_api_hookup (echo_main_t * em)
diff --git a/src/plugins/hs_apps/sapi/vpp_echo_common.c b/src/plugins/hs_apps/sapi/vpp_echo_common.c
index 0642ee67429..e38b17cc013 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo_common.c
+++ b/src/plugins/hs_apps/sapi/vpp_echo_common.c
@@ -593,28 +593,6 @@ echo_get_session_from_handle (echo_main_t * em, u64 handle)
 }
 
 int
-wait_for_segment_allocation (u64 segment_handle)
-{
-  echo_main_t *em = &echo_main;
-  f64 timeout;
-  timeout = clib_time_now (&em->clib_time) + TIMEOUT;
-  uword *segment_present;
-  ECHO_LOG (3, "Waiting for segment 0x%lx...", segment_handle);
-  while (clib_time_now (&em->clib_time) < timeout)
-    {
-      clib_spinlock_lock (&em->segment_handles_lock);
-      segment_present = hash_get (em->shared_segment_handles, segment_handle);
-      clib_spinlock_unlock (&em->segment_handles_lock);
-      if (segment_present != 0)
-	return 0;
-      if (em->time_to_stop == 1)
-	return 0;
-    }
-  ECHO_LOG (2, "timeout wait_for_segment_allocation (0x%lx)", segment_handle);
-  return -1;
-}
-
-int
 wait_for_state_change (echo_main_t * em, connection_state_t state,
 		       f64 timeout)
 {
diff --git a/src/plugins/hs_apps/sapi/vpp_echo_common.h b/src/plugins/hs_apps/sapi/vpp_echo_common.h
index 264d1695af0..0c85b499e9c 100644
--- a/src/plugins/hs_apps/sapi/vpp_echo_common.h
+++ b/src/plugins/hs_apps/sapi/vpp_echo_common.h
@@ -432,7 +432,6 @@ void echo_session_handle_add_del (echo_main_t * em, u64 handle, u32 sid);
 echo_session_t *echo_session_new (echo_main_t * em);
 int echo_send_rpc (echo_main_t * em, void *fp, echo_rpc_args_t * args);
 echo_session_t *echo_get_session_from_handle (echo_main_t * em, u64 handle);
-int wait_for_segment_allocation (u64 segment_handle);
 int wait_for_state_change (echo_main_t * em, connection_state_t state,
 			   f64 timeout);
 void echo_notify_event (echo_main_t * em, echo_test_evt_t e);
@@ -440,6 +439,9 @@ void echo_session_print_stats (echo_main_t * em, echo_session_t * session);
 u8 *echo_format_crypto_engine (u8 * s, va_list * args);
 uword echo_unformat_crypto_engine (unformat_input_t * input, va_list * args);
 u8 *echo_format_bytes_per_sec (u8 * s, va_list * args);
+int echo_ssvm_segment_attach (char *name, ssvm_segment_type_t type, int fd);
+void echo_segment_handle_add_del (echo_main_t * em, u64 segment_handle,
+				  u8 add);
 
 /* Binary API */
 
diff --git a/src/vcl/vcl_bapi.c b/src/vcl/vcl_bapi.c
index b91e928f3e9..efa5cc170ef 100644
--- a/src/vcl/vcl_bapi.c
+++ b/src/vcl/vcl_bapi.c
@@ -61,46 +61,6 @@ static void
     vcm->app_state = STATE_APP_ENABLED;
 }
 
-static int
-vcl_segment_attach (u64 segment_handle, char *name, ssvm_segment_type_t type,
-		    int fd)
-{
-  fifo_segment_create_args_t _a, *a = &_a;
-  int rv;
-
-  memset (a, 0, sizeof (*a));
-  a->segment_name = (char *) name;
-  a->segment_type = type;
-
-  if (type == SSVM_SEGMENT_MEMFD)
-    a->memfd_fd = fd;
-
-  if ((rv = fifo_segment_attach (&vcm->segment_main, a)))
-    {
-      clib_warning ("svm_fifo_segment_attach ('%s') failed", name);
-      return rv;
-    }
-  vcl_segment_table_add (segment_handle, a->new_segment_indices[0]);
-  vec_reset_length (a->new_segment_indices);
-  return 0;
-}
-
-static void
-vcl_segment_detach (u64 segment_handle)
-{
-  fifo_segment_main_t *sm = &vcm->segment_main;
-  fifo_segment_t *segment;
-  u32 segment_index;
-
-  segment_index = vcl_segment_table_lookup (segment_handle);
-  if (segment_index == (u32) ~ 0)
-    return;
-  segment = fifo_segment_get_segment (sm, segment_index);
-  fifo_segment_delete (sm, segment);
-  vcl_segment_table_del (segment_handle);
-  VDBG (0, "detached segment %u handle %u", segment_index, segment_handle);
-}
-
 static u64
 vcl_vpp_worker_segment_handle (u32 wrk_index)
 {
@@ -260,46 +220,6 @@ failed:
 }
 
 static void
-vl_api_map_another_segment_t_handler (vl_api_map_another_segment_t * mp)
-{
-  ssvm_segment_type_t seg_type = SSVM_SEGMENT_SHM;
-  u64 segment_handle;
-  int fd = -1;
-
-  if (mp->fd_flags)
-    {
-      vl_socket_client_recv_fd_msg (&fd, 1, 5);
-      seg_type = SSVM_SEGMENT_MEMFD;
-    }
-
-  segment_handle = clib_net_to_host_u64 (mp->segment_handle);
-  if (segment_handle == VCL_INVALID_SEGMENT_HANDLE)
-    {
-      clib_warning ("invalid segment handle");
-      return;
-    }
-
-  if (vcl_segment_attach (segment_handle, (char *) mp->segment_name,
-			  seg_type, fd))
-    {
-      clib_warning ("VCL<%d>: svm_fifo_segment_attach ('%s') failed",
-		    getpid (), mp->segment_name);
-      return;
-    }
-
-  VDBG (1, "VCL<%d>: mapped new segment '%s' size %d", getpid (),
-	mp->segment_name, mp->segment_size);
-}
-
-static void
-vl_api_unmap_segment_t_handler (vl_api_unmap_segment_t * mp)
-{
-  u64 segment_handle = clib_net_to_host_u64 (mp->segment_handle);
-  vcl_segment_detach (segment_handle);
-  VDBG (1, "Unmapped segment: %d", segment_handle);
-}
-
-static void
   vl_api_application_tls_cert_add_reply_t_handler
   (vl_api_application_tls_cert_add_reply_t * mp)
 {
@@ -322,8 +242,6 @@ _(SESSION_ENABLE_DISABLE_REPLY, session_enable_disable_reply)   	\
 _(APP_ATTACH_REPLY, app_attach_reply)           			\
 _(APPLICATION_TLS_CERT_ADD_REPLY, application_tls_cert_add_reply)  	\
 _(APPLICATION_TLS_KEY_ADD_REPLY, application_tls_key_add_reply)  	\
-_(MAP_ANOTHER_SEGMENT, map_another_segment)                     	\
-_(UNMAP_SEGMENT, unmap_segment)						\
 _(APP_WORKER_ADD_DEL_REPLY, app_worker_add_del_reply)			\
 
 void
diff --git a/src/vcl/vcl_private.c b/src/vcl/vcl_private.c
index 6e887c878cd..f3cee5d6f8e 100644
--- a/src/vcl/vcl_private.c
+++ b/src/vcl/vcl_private.c
@@ -405,6 +405,47 @@ vcl_session_write_ready (vcl_session_t * session)
   return svm_fifo_max_enqueue_prod (session->tx_fifo);
 }
 
+int
+vcl_segment_attach (u64 segment_handle, char *name, ssvm_segment_type_t type,
+		    int fd)
+{
+  fifo_segment_create_args_t _a, *a = &_a;
+  int rv;
+
+  memset (a, 0, sizeof (*a));
+  a->segment_name = (char *) name;
+  a->segment_type = type;
+
+  if (type == SSVM_SEGMENT_MEMFD)
+    a->memfd_fd = fd;
+
+  if ((rv = fifo_segment_attach (&vcm->segment_main, a)))
+    {
+      clib_warning ("svm_fifo_segment_attach ('%s') failed", name);
+      return rv;
+    }
+  vcl_segment_table_add (segment_handle, a->new_segment_indices[0]);
+  vec_reset_length (a->new_segment_indices);
+  return 0;
+}
+
+void
+vcl_segment_detach (u64 segment_handle)
+{
+  fifo_segment_main_t *sm = &vcm->segment_main;
+  fifo_segment_t *segment;
+  u32 segment_index;
+
+  segment_index = vcl_segment_table_lookup (segment_handle);
+  if (segment_index == (u32) ~ 0)
+    return;
+  segment = fifo_segment_get_segment (sm, segment_index);
+  fifo_segment_delete (sm, segment);
+  vcl_segment_table_del (segment_handle);
+  VDBG (0, "detached segment %u handle %u", segment_index, segment_handle);
+}
+
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vcl/vcl_private.h b/src/vcl/vcl_private.h
index 9116111afe2..db4bcd315b6 100644
--- a/src/vcl/vcl_private.h
+++ b/src/vcl/vcl_private.h
@@ -626,6 +626,10 @@ void vppcom_send_application_tls_key_add (vcl_session_t * session, char *key,
 void vcl_send_app_worker_add_del (u8 is_add);
 void vcl_send_child_worker_del (vcl_worker_t * wrk);
 
+int vcl_segment_attach (u64 segment_handle, char *name,
+			ssvm_segment_type_t type, int fd);
+void vcl_segment_detach (u64 segment_handle);
+
 u32 vcl_max_nsid_len (void);
 
 u8 *format_api_error (u8 * s, va_list * args);
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index a854011fa0d..4224a086a21 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -23,23 +23,17 @@
 __thread uword __vcl_worker_index = ~0;
 
 static int
-vcl_wait_for_segment (u64 segment_handle)
+vcl_segment_is_not_mounted (vcl_worker_t * wrk, u64 segment_handle)
 {
-  vcl_worker_t *wrk = vcl_worker_get_current ();
-  u32 wait_for_seconds = 10, segment_index;
-  f64 timeout;
+  u32 segment_index;
 
   if (segment_handle == VCL_INVALID_SEGMENT_HANDLE)
     return 0;
 
-  timeout = clib_time_now (&wrk->clib_time) + wait_for_seconds;
-  while (clib_time_now (&wrk->clib_time) < timeout)
-    {
-      segment_index = vcl_segment_table_lookup (segment_handle);
-      if (segment_index != VCL_INVALID_SEGMENT_INDEX)
-	return 0;
-      usleep (10);
-    }
+  segment_index = vcl_segment_table_lookup (segment_handle);
+  if (segment_index != VCL_INVALID_SEGMENT_INDEX)
+    return 0;
+
   return 1;
 }
 
@@ -371,9 +365,9 @@ vcl_session_accepted_handler (vcl_worker_t * wrk, session_accepted_msg_t * mp,
       goto error;
     }
 
-  if (vcl_wait_for_segment (mp->segment_handle))
+  if (vcl_segment_is_not_mounted (wrk, mp->segment_handle))
     {
-      VDBG (0, "ERROR: segment for session %u couldn't be mounted!",
+      VDBG (0, "ERROR: segment for session %u is not mounted!",
 	    session->session_index);
       goto error;
     }
@@ -459,9 +453,9 @@ vcl_session_connected_handler (vcl_worker_t * wrk,
 					 svm_msg_q_t *);
   rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
   tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
-  if (vcl_wait_for_segment (mp->segment_handle))
+  if (vcl_segment_is_not_mounted (wrk, mp->segment_handle))
     {
-      VDBG (0, "segment for session %u couldn't be mounted!",
+      VDBG (0, "segment for session %u is not mounted!",
 	    session->session_index);
       session->session_state = STATE_FAILED | STATE_DISCONNECT;
       vcl_send_session_disconnect (wrk, session);
@@ -481,9 +475,9 @@ vcl_session_connected_handler (vcl_worker_t * wrk,
     {
       session->ct_rx_fifo = uword_to_pointer (mp->ct_rx_fifo, svm_fifo_t *);
       session->ct_tx_fifo = uword_to_pointer (mp->ct_tx_fifo, svm_fifo_t *);
-      if (vcl_wait_for_segment (mp->ct_segment_handle))
+      if (vcl_segment_is_not_mounted (wrk, mp->ct_segment_handle))
 	{
-	  VDBG (0, "ct segment for session %u couldn't be mounted!",
+	  VDBG (0, "ct segment for session %u is not mounted!",
 		session->session_index);
 	  session->session_state = STATE_FAILED | STATE_DISCONNECT;
 	  vcl_send_session_disconnect (wrk, session);
@@ -715,9 +709,9 @@ vcl_session_worker_update_reply_handler (vcl_worker_t * wrk, void *data)
       VDBG (0, "unknown handle 0x%llx", msg->handle);
       return;
     }
-  if (vcl_wait_for_segment (msg->segment_handle))
+  if (vcl_segment_is_not_mounted (wrk, msg->segment_handle))
     {
-      clib_warning ("segment for session %u couldn't be mounted!",
+      clib_warning ("segment for session %u is not mounted!",
 		    s->session_index);
       return;
     }
@@ -737,6 +731,48 @@ vcl_session_worker_update_reply_handler (vcl_worker_t * wrk, void *data)
 	s->vpp_handle, wrk->wrk_index);
 }
 
+static void
+vcl_session_app_add_segment_handler (vcl_worker_t * wrk, void *data)
+{
+  ssvm_segment_type_t seg_type = SSVM_SEGMENT_SHM;
+  session_app_add_segment_msg_t *msg;
+  u64 segment_handle;
+  int fd = -1;
+
+  msg = (session_app_add_segment_msg_t *) data;
+
+  if (msg->fd_flags)
+    {
+      vl_socket_client_recv_fd_msg2 (&wrk->bapi_sock_ctx, &fd, 1, 5);
+      seg_type = SSVM_SEGMENT_MEMFD;
+    }
+
+  segment_handle = msg->segment_handle;
+  if (segment_handle == VCL_INVALID_SEGMENT_HANDLE)
+    {
+      clib_warning ("invalid segment handle");
+      return;
+    }
+
+  if (vcl_segment_attach (segment_handle, (char *) msg->segment_name,
+			  seg_type, fd))
+    {
+      VDBG (0, "vcl_segment_attach ('%s') failed", msg->segment_name);
+      return;
+    }
+
+  VDBG (1, "mapped new segment '%s' size %d", msg->segment_name,
+	msg->segment_size);
+}
+
+static void
+vcl_session_app_del_segment_handler (vcl_worker_t * wrk, void *data)
+{
+  session_app_del_segment_msg_t *msg = (session_app_del_segment_msg_t *) data;
+  vcl_segment_detach (msg->segment_handle);
+  VDBG (1, "Unmapped segment: %d", msg->segment_handle);
+}
+
 static int
 vcl_handle_mq_event (vcl_worker_t * wrk, session_event_t * e)
 {
@@ -782,6 +818,12 @@ vcl_handle_mq_event (vcl_worker_t * wrk, session_event_t * e)
     case SESSION_CTRL_EVT_WORKER_UPDATE_REPLY:
       vcl_session_worker_update_reply_handler (wrk, e->data);
       break;
+    case SESSION_CTRL_EVT_APP_ADD_SEGMENT:
+      vcl_session_app_add_segment_handler (wrk, e->data);
+      break;
+    case SESSION_CTRL_EVT_APP_DEL_SEGMENT:
+      vcl_session_app_del_segment_handler (wrk, e->data);
+      break;
     default:
       clib_warning ("unhandled %u", e->event_type);
     }
@@ -2091,6 +2133,12 @@ vcl_select_handle_mq_event (vcl_worker_t * wrk, session_event_t * e,
     case SESSION_CTRL_EVT_REQ_WORKER_UPDATE:
       vcl_session_req_worker_update_handler (wrk, e->data);
       break;
+    case SESSION_CTRL_EVT_APP_ADD_SEGMENT:
+      vcl_session_app_add_segment_handler (wrk, e->data);
+      break;
+    case SESSION_CTRL_EVT_APP_DEL_SEGMENT:
+      vcl_session_app_del_segment_handler (wrk, e->data);
+      break;
     default:
       clib_warning ("unhandled: %u", e->event_type);
       break;
@@ -2669,6 +2717,12 @@ vcl_epoll_wait_handle_mq_event (vcl_worker_t * wrk, session_event_t * e,
     case SESSION_CTRL_EVT_WORKER_UPDATE_REPLY:
       vcl_session_worker_update_reply_handler (wrk, e->data);
       break;
+    case SESSION_CTRL_EVT_APP_ADD_SEGMENT:
+      vcl_session_app_add_segment_handler (wrk, e->data);
+      break;
+    case SESSION_CTRL_EVT_APP_DEL_SEGMENT:
+      vcl_session_app_del_segment_handler (wrk, e->data);
+      break;
     default:
       VDBG (0, "unhandled: %u", e->event_type);
       break;
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index a40aa9d9a7f..2e850a98e57 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -29,13 +29,13 @@ typedef struct certificate_
   u8 *cert;
 } app_cert_key_pair_t;
 
-typedef struct _stream_session_cb_vft
+typedef struct session_cb_vft_
 {
   /** Notify server of new segment */
-  int (*add_segment_callback) (u32 api_client_index, u64 segment_handle);
+  int (*add_segment_callback) (u32 app_wrk_index, u64 segment_handle);
 
   /** Notify server of new segment */
-  int (*del_segment_callback) (u32 api_client_index, u64 segment_handle);
+  int (*del_segment_callback) (u32 app_wrk_index, u64 segment_handle);
 
   /** Notify server of newly accepted session */
   int (*session_accept_callback) (session_t * new_session);
@@ -485,6 +485,23 @@ typedef struct session_app_detach_msg_
   u32 context;
 } session_app_detach_msg_t;
 
+typedef struct app_map_another_segment_msg_
+{
+  u32 client_index;
+  u32 context;
+  u8 fd_flags;
+  u32 segment_size;
+  u8 segment_name[128];
+  u64 segment_handle;
+} session_app_add_segment_msg_t;
+
+typedef struct app_unmap_segment_msg_
+{
+  u32 client_index;
+  u32 context;
+  u64 segment_handle;
+} session_app_del_segment_msg_t;
+
 typedef struct app_session_event_
 {
   svm_msg_q_msg_t msg;
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index bb51cb71f03..1db6baab74e 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -526,7 +526,8 @@ int
 app_worker_add_segment_notify (app_worker_t * app_wrk, u64 segment_handle)
 {
   application_t *app = application_get (app_wrk->app_index);
-  return app->cb_fns.add_segment_callback (app_wrk->api_client_index,
+
+  return app->cb_fns.add_segment_callback (app_wrk->wrk_index,
 					   segment_handle);
 }
 
@@ -534,7 +535,7 @@ int
 app_worker_del_segment_notify (app_worker_t * app_wrk, u64 segment_handle)
 {
   application_t *app = application_get (app_wrk->app_index);
-  return app->cb_fns.del_segment_callback (app_wrk->api_client_index,
+  return app->cb_fns.del_segment_callback (app_wrk->wrk_index,
 					   segment_handle);
 }
 
diff --git a/src/vnet/session/session.api b/src/vnet/session/session.api
index 33e53419a8d..4f9ae12eeb3 100644
--- a/src/vnet/session/session.api
+++ b/src/vnet/session/session.api
@@ -187,6 +187,7 @@ autoreply define application_detach {
  };
 
 /** \brief vpp->client, please map an additional shared memory segment
+	### WILL BE DEPRECATED POST 20.01 ###
     @param client_index - opaque cookie to identify the sender
     @param context - sender context, to match reply w/ request
    	@param fd_flags - set of flags that indicate which, if any, fds are
@@ -206,6 +207,7 @@ autoreply define map_another_segment {
 };
 
 /** \brief vpp->client unmap shared memory segment
+	### WILL BE DEPRECATED POST 20.01 ###
     @param client_index - opaque cookie to identify the sender
     @param context - sender context, to match reply w/ request
     @param segment_name - segment name
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index 99e00a78bf3..153c528059c 100644
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -81,6 +81,7 @@ session_send_fds (vl_api_registration_t * reg, int fds[], int n_fds)
   return 0;
 }
 
+/* ### WILL BE DEPRECATED POST 20.01 ### */
 static int
 send_add_segment_callback (u32 api_client_index, u64 segment_handle)
 {
@@ -130,6 +131,7 @@ send_add_segment_callback (u32 api_client_index, u64 segment_handle)
   return 0;
 }
 
+/* ### WILL BE DEPRECATED POST 20.01 ### */
 static int
 send_del_segment_callback (u32 api_client_index, u64 segment_handle)
 {
@@ -471,7 +473,103 @@ mq_send_session_migrate_cb (session_t * s, session_handle_t new_sh)
   clib_warning ("not supported");
 }
 
-static session_cb_vft_t session_mq_cb_vft = {
+static int
+mq_send_add_segment_cb (u32 app_wrk_index, u64 segment_handle)
+{
+  int fds[SESSION_N_FD_TYPE], n_fds = 0;
+  svm_msg_q_msg_t _msg, *msg = &_msg;
+  session_app_add_segment_msg_t *mp;
+  vl_api_registration_t *reg;
+  app_worker_t *app_wrk;
+  session_event_t *evt;
+  svm_msg_q_t *app_mq;
+  fifo_segment_t *fs;
+  ssvm_private_t *sp;
+  u8 fd_flags = 0;
+
+  app_wrk = app_worker_get (app_wrk_index);
+
+  reg = vl_mem_api_client_index_to_registration (app_wrk->api_client_index);
+  if (!reg)
+    {
+      clib_warning ("no api registration for client: %u",
+		    app_wrk->api_client_index);
+      return -1;
+    }
+
+  fs = segment_manager_get_segment_w_handle (segment_handle);
+  sp = &fs->ssvm;
+  if (ssvm_type (sp) == SSVM_SEGMENT_MEMFD)
+    {
+      if (vl_api_registration_file_index (reg) == VL_API_INVALID_FI)
+	{
+	  clib_warning ("can't send memfd fd");
+	  return -1;
+	}
+
+      fd_flags |= SESSION_FD_F_MEMFD_SEGMENT;
+      fds[n_fds] = sp->fd;
+      n_fds += 1;
+    }
+
+  app_mq = app_wrk->event_queue;
+  if (mq_try_lock_and_alloc_msg (app_mq, msg))
+    return -1;
+
+  if (n_fds)
+    session_send_fds (reg, fds, n_fds);
+
+  evt = svm_msg_q_msg_data (app_mq, msg);
+  clib_memset (evt, 0, sizeof (*evt));
+  evt->event_type = SESSION_CTRL_EVT_APP_ADD_SEGMENT;
+  mp = (session_app_add_segment_msg_t *) evt->data;
+  clib_memset (mp, 0, sizeof (*mp));
+  mp->segment_size = sp->ssvm_size;
+  mp->fd_flags = fd_flags;
+  mp->segment_handle = segment_handle;
+  strncpy ((char *) mp->segment_name, (char *) sp->name,
+	   sizeof (mp->segment_name) - 1);
+
+  svm_msg_q_add_and_unlock (app_mq, msg);
+
+  return 0;
+}
+
+static int
+mq_send_del_segment_cb (u32 app_wrk_index, u64 segment_handle)
+{
+  svm_msg_q_msg_t _msg, *msg = &_msg;
+  session_app_del_segment_msg_t *mp;
+  vl_api_registration_t *reg;
+  app_worker_t *app_wrk;
+  session_event_t *evt;
+  svm_msg_q_t *app_mq;
+
+  app_wrk = app_worker_get (app_wrk_index);
+  reg = vl_mem_api_client_index_to_registration (app_wrk->api_client_index);
+  if (!reg)
+    {
+      clib_warning ("no registration: %u", app_wrk->api_client_index);
+      return -1;
+    }
+
+  app_mq = app_wrk->event_queue;
+  if (mq_try_lock_and_alloc_msg (app_mq, msg))
+    return -1;
+
+  evt = svm_msg_q_msg_data (app_mq, msg);
+  clib_memset (evt, 0, sizeof (*evt));
+  evt->event_type = SESSION_CTRL_EVT_APP_DEL_SEGMENT;
+  mp = (session_app_del_segment_msg_t *) evt->data;
+  clib_memset (mp, 0, sizeof (*mp));
+  mp->segment_handle = segment_handle;
+  svm_msg_q_add_and_unlock (app_mq, msg);
+
+  return 0;
+}
+
+/* ### WILL BE DEPRECATED POST 20.01 ### */
+static session_cb_vft_t session_mq_cb_vft_old = {
   .session_accept_callback = mq_send_session_accepted_cb,
   .session_disconnect_callback = mq_send_session_disconnected_cb,
   .session_connected_callback = mq_send_session_connected_cb,
@@ -481,6 +579,16 @@ static session_cb_vft_t session_mq_cb_vft = {
   .del_segment_callback = send_del_segment_callback,
 };
 
+static session_cb_vft_t session_mq_cb_vft = {
+  .session_accept_callback = mq_send_session_accepted_cb,
+  .session_disconnect_callback = mq_send_session_disconnected_cb,
+  .session_connected_callback = mq_send_session_connected_cb,
+  .session_reset_callback = mq_send_session_reset_cb,
+  .session_migrate_callback = mq_send_session_migrate_cb,
+  .add_segment_callback = mq_send_add_segment_cb,
+  .del_segment_callback = mq_send_del_segment_cb,
+};
+
 static void
 vl_api_session_enable_disable_t_handler (vl_api_session_enable_disable_t * mp)
 {
@@ -520,7 +628,7 @@ vl_api_application_attach_t_handler (vl_api_application_attach_t * mp)
   clib_memset (a, 0, sizeof (*a));
   a->api_client_index = mp->client_index;
   a->options = mp->options;
-  a->session_cb_vft = &session_mq_cb_vft;
+  a->session_cb_vft = &session_mq_cb_vft_old;
   if (mp->namespace_id_len > 64)
     {
       rv = VNET_API_ERROR_INVALID_VALUE;
@@ -888,6 +996,7 @@ vl_api_disconnect_session_reply_t_handler (vl_api_disconnect_session_reply_t *
     }
 }
 
+/* ### WILL BE DEPRECATED POST 20.01 ### */
 static void
 vl_api_map_another_segment_reply_t_handler (vl_api_map_another_segment_reply_t
 					    * mp)
diff --git a/src/vnet/session/session_types.h b/src/vnet/session/session_types.h
index 16d48431572..ce593b0b38c 100644
--- a/src/vnet/session/session_types.h
+++ b/src/vnet/session/session_types.h
@@ -334,6 +334,8 @@ typedef enum
   SESSION_CTRL_EVT_LISTEN_URI,
   SESSION_CTRL_EVT_UNLISTEN,
   SESSION_CTRL_EVT_APP_DETACH,
+  SESSION_CTRL_EVT_APP_ADD_SEGMENT,
+  SESSION_CTRL_EVT_APP_DEL_SEGMENT,
 } session_evt_type_t;
 
 #define foreach_session_ctrl_evt				\
@@ -355,7 +357,8 @@ typedef enum
   _(WORKER_UPDATE, worker_update)				\
   _(WORKER_UPDATE_REPLY, worker_update_reply)			\
   _(APP_DETACH, app_detach)					\
-
+  _(APP_ADD_SEGMENT, app_add_segment)				\
+  _(APP_DEL_SEGMENT, app_del_segment)				\
 
 /* Deprecated and will be removed. Use types above */
 #define FIFO_EVENT_APP_RX SESSION_IO_EVT_RX