session: support local sessions and deprecate redirects

Memfd backed shared memory segments can only be negotiated over sockets.
For such scenarios, the existing redirect mechanism that establishes
cut-through sessions does not work anymore as the two peer application
do not share such a socket.

This patch adds support for local sessions, as opposed to sessions
backed by a transport connection, in a way that is almost transparent to
the two applications by reusing the existing binary api messages.
Moreover, all segment allocations are now entirely done through the
segment manager valloc, so segment overlaps due to independent
allocations previously required for redirects are completely avoided.
The one notable characteristic of local sessions (cut-through from app
perspective) notification messages is that they carry pointers to two
event queues, one for each app peer, instead of one. For
transport-backed sessions one of the queues can be inferred but for
local session they cannot.

Change-Id: Ia443fb63e2d9d8e43490275062a708f039038175
Signed-off-by: Florin Coras <fcoras@cisco.com>

2 files changed, 87 insertions, 44 deletions

diff --git a/src/tests/vnet/session/tcp_echo.c b/src/tests/vnet/session/tcp_echo.c
index d48c5d9de03..a925384b6e4 100644
--- a/src/tests/vnet/session/tcp_echo.c
+++ b/src/tests/vnet/session/tcp_echo.c
@@ -479,6 +479,7 @@ vl_api_disconnect_session_t_handler (vl_api_disconnect_session_t * mp)
   rmp->_vl_msg_id = ntohs (VL_API_DISCONNECT_SESSION_REPLY);
   rmp->retval = rv;
   rmp->handle = mp->handle;
+  rmp->context = mp->context;
   vl_msg_api_send_shmem (em->vl_input_queue, (u8 *) & rmp);
 
   if (session)
diff --git a/src/tests/vnet/session/udp_echo.c b/src/tests/vnet/session/udp_echo.c
index e425169b944..d1363fc7104 100644
--- a/src/tests/vnet/session/udp_echo.c
+++ b/src/tests/vnet/session/udp_echo.c
@@ -126,6 +126,8 @@ typedef struct
   svm_fifo_segment_main_t *segment_main;
 
   u8 *connect_test_data;
+
+  uword *segments_table;
 } uri_udp_test_main_t;
 
 #if CLIB_DEBUG > 0
@@ -173,8 +175,9 @@ application_send_attach (uri_udp_test_main_t * utm)
   bmp->_vl_msg_id = ntohs (VL_API_APPLICATION_ATTACH);
   bmp->client_index = utm->my_client_index;
   bmp->context = ntohl (0xfeedface);
-  bmp->options[APP_OPTIONS_FLAGS] =
-    APP_OPTIONS_FLAGS_ACCEPT_REDIRECT | APP_OPTIONS_FLAGS_ADD_SEGMENT;
+  bmp->options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_ADD_SEGMENT;
+  bmp->options[APP_OPTIONS_FLAGS] |= APP_OPTIONS_FLAGS_USE_GLOBAL_SCOPE;
+  bmp->options[APP_OPTIONS_FLAGS] |= APP_OPTIONS_FLAGS_USE_LOCAL_SCOPE;
   bmp->options[APP_OPTIONS_PREALLOC_FIFO_PAIRS] = 2;
   bmp->options[APP_OPTIONS_RX_FIFO_SIZE] = fifo_size;
   bmp->options[APP_OPTIONS_TX_FIFO_SIZE] = fifo_size;
@@ -308,7 +311,7 @@ cut_through_thread_fn (void *arg)
       /* We read from the tx fifo and write to the rx fifo */
       do
 	{
-	  actual_transfer = svm_fifo_dequeue_nowait (tx_fifo,
+	  actual_transfer = svm_fifo_dequeue_nowait (rx_fifo,
 						     vec_len (my_copy_buffer),
 						     my_copy_buffer);
 	}
@@ -319,7 +322,7 @@ cut_through_thread_fn (void *arg)
       buffer_offset = 0;
       while (actual_transfer > 0)
 	{
-	  rv = svm_fifo_enqueue_nowait (rx_fifo, actual_transfer,
+	  rv = svm_fifo_enqueue_nowait (tx_fifo, actual_transfer,
 					my_copy_buffer + buffer_offset);
 	  if (rv > 0)
 	    {
@@ -605,7 +608,10 @@ vl_api_bind_uri_reply_t_handler (vl_api_bind_uri_reply_t * mp)
 static void
 vl_api_map_another_segment_t_handler (vl_api_map_another_segment_t * mp)
 {
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
   svm_fifo_segment_create_args_t _a, *a = &_a;
+  svm_fifo_segment_private_t *seg;
+  u8 *seg_name;
   int rv;
 
   memset (a, 0, sizeof (*a));
@@ -619,8 +625,35 @@ vl_api_map_another_segment_t_handler (vl_api_map_another_segment_t * mp)
 		    mp->segment_name);
       return;
     }
-  clib_warning ("Mapped new segment '%s' size %d", mp->segment_name,
-		mp->segment_size);
+  seg = svm_fifo_segment_get_segment (a->new_segment_indices[0]);
+  clib_warning ("Mapped new segment '%s' size %d", seg->ssvm.name,
+		seg->ssvm.ssvm_size);
+  seg_name = format (0, "%s", (char *) mp->segment_name);
+  hash_set_mem (utm->segments_table, seg_name, a->new_segment_indices[0]);
+  vec_free (seg_name);
+}
+
+static void
+vl_api_unmap_segment_t_handler (vl_api_unmap_segment_t * mp)
+{
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  svm_fifo_segment_private_t *seg;
+  u64 *seg_indexp;
+  u8 *seg_name;
+
+
+  seg_name = format (0, "%s", mp->segment_name);
+  seg_indexp = hash_get_mem (utm->segments_table, seg_name);
+  if (!seg_indexp)
+    {
+      clib_warning ("segment not mapped: %s", seg_name);
+      return;
+    }
+  hash_unset_mem (utm->segments_table, seg_name);
+  seg = svm_fifo_segment_get_segment ((u32) seg_indexp[0]);
+  svm_fifo_segment_delete (seg);
+  clib_warning ("Unmapped segment '%s'", seg_name);
+  vec_free (seg_name);
 }
 
 /**
@@ -720,6 +753,8 @@ vl_api_accept_session_t_handler (vl_api_accept_session_t * mp)
   svm_fifo_t *rx_fifo, *tx_fifo;
   session_t *session;
   static f64 start_time;
+  u32 session_index;
+  int rv = 0;
 
   if (start_time == 0.0)
     start_time = clib_time_now (&utm->clib_time);
@@ -727,19 +762,42 @@ vl_api_accept_session_t_handler (vl_api_accept_session_t * mp)
   utm->vpp_event_queue =
     uword_to_pointer (mp->vpp_event_queue_address, svm_queue_t *);
 
-  pool_get (utm->sessions, session);
-
   rx_fifo = uword_to_pointer (mp->server_rx_fifo, svm_fifo_t *);
-  rx_fifo->client_session_index = session - utm->sessions;
   tx_fifo = uword_to_pointer (mp->server_tx_fifo, svm_fifo_t *);
-  tx_fifo->client_session_index = session - utm->sessions;
 
-  session->server_rx_fifo = rx_fifo;
-  session->server_tx_fifo = tx_fifo;
+  pool_get (utm->sessions, session);
+  memset (session, 0, sizeof (*session));
+  session_index = session - utm->sessions;
 
-  hash_set (utm->session_index_by_vpp_handles, mp->handle,
-	    session - utm->sessions);
+  /* Cut-through case */
+  if (mp->server_event_queue_address)
+    {
+      clib_warning ("cut-through session");
+      utm->our_event_queue = uword_to_pointer (mp->server_event_queue_address,
+					       svm_queue_t *);
+      rx_fifo->master_session_index = session_index;
+      tx_fifo->master_session_index = session_index;
+      utm->cut_through_session_index = session_index;
+      session->server_rx_fifo = rx_fifo;
+      session->server_tx_fifo = tx_fifo;
+
+      rv = pthread_create (&utm->cut_through_thread_handle,
+			   NULL /*attr */ , cut_through_thread_fn, 0);
+      if (rv)
+	{
+	  clib_warning ("pthread_create returned %d", rv);
+	  rv = VNET_API_ERROR_SYSCALL_ERROR_1;
+	}
+    }
+  else
+    {
+      rx_fifo->client_session_index = session_index;
+      tx_fifo->client_session_index = session_index;
+      session->server_rx_fifo = rx_fifo;
+      session->server_tx_fifo = tx_fifo;
+    }
 
+  hash_set (utm->session_index_by_vpp_handles, mp->handle, session_index);
   if (pool_elts (utm->sessions) && (pool_elts (utm->sessions) % 20000) == 0)
     {
       f64 now = clib_time_now (&utm->clib_time);
@@ -753,6 +811,7 @@ vl_api_accept_session_t_handler (vl_api_accept_session_t * mp)
   rmp->_vl_msg_id = ntohs (VL_API_ACCEPT_SESSION_REPLY);
   rmp->handle = mp->handle;
   rmp->context = mp->context;
+  rmp->retval = rv;
   vl_msg_api_send_shmem (utm->vl_input_queue, (u8 *) & rmp);
 
   CLIB_MEMORY_BARRIER ();
@@ -787,6 +846,7 @@ vl_api_disconnect_session_t_handler (vl_api_disconnect_session_t * mp)
   rmp->_vl_msg_id = ntohs (VL_API_DISCONNECT_SESSION_REPLY);
   rmp->retval = rv;
   rmp->handle = mp->handle;
+  rmp->context = mp->context;
   vl_msg_api_send_shmem (utm->vl_input_queue, (u8 *) & rmp);
 }
 
@@ -804,34 +864,6 @@ vl_api_connect_session_reply_t_handler (vl_api_connect_session_reply_t * mp)
       return;
     }
 
-  /* We've been redirected */
-  if (mp->segment_name_length > 0)
-    {
-      svm_fifo_segment_main_t *sm = &svm_fifo_segment_main;
-      svm_fifo_segment_create_args_t _a, *a = &_a;
-      u32 segment_index;
-      svm_fifo_segment_private_t *seg;
-      int rv;
-
-      memset (a, 0, sizeof (*a));
-      a->segment_name = (char *) mp->segment_name;
-
-      sleep (1);
-
-      rv = svm_fifo_segment_attach (a);
-      if (rv)
-	{
-	  clib_warning ("sm_fifo_segment_create ('%v') failed",
-			mp->segment_name);
-	  return;
-	}
-
-      segment_index = a->new_segment_indices[0];
-      vec_add2 (utm->seg, seg, 1);
-      memcpy (seg, sm->segments + segment_index, sizeof (*seg));
-      sleep (1);
-    }
-
   pool_get (utm->sessions, session);
   session->server_rx_fifo = uword_to_pointer (mp->server_rx_fifo,
 					      svm_fifo_t *);
@@ -840,8 +872,16 @@ vl_api_connect_session_reply_t_handler (vl_api_connect_session_reply_t * mp)
 					      svm_fifo_t *);
   ASSERT (session->server_tx_fifo);
 
-  if (mp->segment_name_length > 0)
-    utm->cut_through_session_index = session - utm->sessions;
+  /* Cut-through case */
+  if (mp->client_event_queue_address)
+    {
+      clib_warning ("cut-through session");
+      utm->cut_through_session_index = session - utm->sessions;
+      utm->vpp_event_queue = uword_to_pointer (mp->vpp_event_queue_address,
+					       svm_queue_t *);
+      utm->our_event_queue = uword_to_pointer (mp->client_event_queue_address,
+					       svm_queue_t *);
+    }
   else
     {
       utm->connected_session = session - utm->sessions;
@@ -859,6 +899,7 @@ _(UNBIND_URI_REPLY, unbind_uri_reply)           	\
 _(ACCEPT_SESSION, accept_session)			\
 _(DISCONNECT_SESSION, disconnect_session)		\
 _(MAP_ANOTHER_SEGMENT, map_another_segment)		\
+_(UNMAP_SEGMENT, unmap_segment)				\
 _(APPLICATION_ATTACH_REPLY, application_attach_reply)	\
 _(APPLICATION_DETACH_REPLY, application_detach_reply)	\
 
@@ -1068,6 +1109,7 @@ main (int argc, char **argv)
   utm->session_index_by_vpp_handles = hash_create (0, sizeof (uword));
   utm->my_pid = getpid ();
   utm->configured_segment_size = 1 << 20;
+  utm->segments_table = hash_create_vec (0, sizeof (u8), sizeof (u64));
 
   clib_time_init (&utm->clib_time);
   init_error_string_table (utm);