udp/session: refactor to support dgram mode

- adds session layer support for datagram based protocols
- updates udp to work in pure connectionless and datagram mode. The
  existing connected mode is now 'accessible' for apps as a dummy UDPC,
  as in, connected udp, protocol.
- updates udp_echo, echo client, echo server code to work in datagram
  mode.

Change-Id: I2960c0d2d246cb166005f545794ec31fe0d546dd
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 62 insertions, 42 deletions

diff --git a/src/vnet/session-apps/echo_server.c b/src/vnet/session-apps/echo_server.c
index 0bde2e4995f..85e6c299919 100644
--- a/src/vnet/session-apps/echo_server.c
+++ b/src/vnet/session-apps/echo_server.c
@@ -34,13 +34,14 @@ typedef struct
    * Config params
    */
   u8 no_echo;			/**< Don't echo traffic */
-  u32 fifo_size;			/**< Fifo size */
+  u32 fifo_size;		/**< Fifo size */
   u32 rcv_buffer_size;		/**< Rcv buffer size */
   u32 prealloc_fifos;		/**< Preallocate fifos */
   u32 private_segment_count;	/**< Number of private segments  */
   u32 private_segment_size;	/**< Size of private segments  */
   char *server_uri;		/**< Server URI */
   u32 tls_engine;		/**< TLS engine: mbedtls/openssl */
+  u8 is_dgram;			/**< set if transport is dgram */
   /*
    * Test state
    */
@@ -126,25 +127,13 @@ test_bytes (echo_server_main_t * esm, int actual_transfer)
 }
 
 /*
- * If no-echo, just read the data and be done with it
+ * If no-echo, just drop the data and be done with it.
  */
 int
 echo_server_builtin_server_rx_callback_no_echo (stream_session_t * s)
 {
-  echo_server_main_t *esm = &echo_server_main;
-  u32 my_thread_id = vlib_get_thread_index ();
-  int actual_transfer;
-  svm_fifo_t *rx_fifo;
-
-  rx_fifo = s->server_rx_fifo;
-
-  do
-    {
-      actual_transfer =
-	svm_fifo_dequeue_nowait (rx_fifo, esm->rcv_buffer_size,
-				 esm->rx_buf[my_thread_id]);
-    }
-  while (actual_transfer > 0);
+  svm_fifo_t *rx_fifo = s->server_rx_fifo;
+  svm_fifo_dequeue_drop (rx_fifo, svm_fifo_max_dequeue (rx_fifo));
   return 0;
 }
 
@@ -157,6 +146,8 @@ echo_server_rx_callback (stream_session_t * s)
   echo_server_main_t *esm = &echo_server_main;
   session_fifo_event_t evt;
   u32 thread_index = vlib_get_thread_index ();
+  app_session_transport_t at;
+  svm_queue_t *q;
 
   ASSERT (s->thread_index == thread_index);
 
@@ -166,14 +157,29 @@ echo_server_rx_callback (stream_session_t * s)
   ASSERT (rx_fifo->master_thread_index == thread_index);
   ASSERT (tx_fifo->master_thread_index == thread_index);
 
-  max_dequeue = svm_fifo_max_dequeue (s->server_rx_fifo);
-  max_enqueue = svm_fifo_max_enqueue (s->server_tx_fifo);
+  max_enqueue = svm_fifo_max_enqueue (tx_fifo);
+  if (!esm->is_dgram)
+    {
+      max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+    }
+  else
+    {
+      session_dgram_pre_hdr_t ph;
+      svm_fifo_peek (rx_fifo, 0, sizeof (ph), (u8 *) & ph);
+      max_dequeue = ph.data_length - ph.data_offset;
+      if (!esm->vpp_queue[s->thread_index])
+	{
+	  q = session_manager_get_vpp_event_queue (s->thread_index);
+	  esm->vpp_queue[s->thread_index] = q;
+	}
+      max_enqueue -= sizeof (session_dgram_hdr_t);
+    }
 
   if (PREDICT_FALSE (max_dequeue == 0))
     return 0;
 
   /* Number of bytes we're going to copy */
-  max_transfer = (max_dequeue < max_enqueue) ? max_dequeue : max_enqueue;
+  max_transfer = clib_min (max_dequeue, max_enqueue);
 
   /* No space in tx fifo */
   if (PREDICT_FALSE (max_transfer == 0))
@@ -184,16 +190,16 @@ echo_server_rx_callback (stream_session_t * s)
       /* Program self-tap to retry */
       if (svm_fifo_set_event (rx_fifo))
 	{
-	  svm_queue_t *q;
 	  evt.fifo = rx_fifo;
 	  evt.event_type = FIFO_EVENT_BUILTIN_RX;
 
-	  q = esm->vpp_queue[thread_index];
+	  q = esm->vpp_queue[s->thread_index];
 	  if (PREDICT_FALSE (q->cursize == q->maxsize))
 	    clib_warning ("out of event queue space");
 	  else if (svm_queue_add (q, (u8 *) & evt, 0))
 	    clib_warning ("failed to enqueue self-tap");
 
+	  vec_validate (esm->rx_retries[s->thread_index], s->session_index);
 	  if (esm->rx_retries[thread_index][s->session_index] == 500000)
 	    {
 	      clib_warning ("session stuck: %U", format_stream_session, s, 2);
@@ -205,36 +211,47 @@ echo_server_rx_callback (stream_session_t * s)
       return 0;
     }
 
-  _vec_len (esm->rx_buf[thread_index]) = max_transfer;
-
-  actual_transfer = svm_fifo_dequeue_nowait (rx_fifo, max_transfer,
-					     esm->rx_buf[thread_index]);
+  vec_validate (esm->rx_buf[thread_index], max_transfer);
+  if (!esm->is_dgram)
+    {
+      actual_transfer = app_recv_stream_raw (rx_fifo,
+					     esm->rx_buf[thread_index],
+					     max_transfer,
+					     0 /* don't clear event */ );
+    }
+  else
+    {
+      actual_transfer = app_recv_dgram_raw (rx_fifo,
+					    esm->rx_buf[thread_index],
+					    max_transfer, &at,
+					    0 /* don't clear event */ );
+    }
   ASSERT (actual_transfer == max_transfer);
-
-//  test_bytes (esm, actual_transfer);
+  /* test_bytes (esm, actual_transfer); */
 
   /*
    * Echo back
    */
 
-  n_written = svm_fifo_enqueue_nowait (tx_fifo, actual_transfer,
-				       esm->rx_buf[thread_index]);
-
-  if (n_written != max_transfer)
-    clib_warning ("short trout!");
-
-  if (svm_fifo_set_event (tx_fifo))
+  if (!esm->is_dgram)
     {
-      /* Fabricate TX event, send to vpp */
-      evt.fifo = tx_fifo;
-      evt.event_type = FIFO_EVENT_APP_TX;
-
-      if (svm_queue_add (esm->vpp_queue[s->thread_index],
-			 (u8 *) & evt, 0 /* do wait for mutex */ ))
-	clib_warning ("failed to enqueue tx evt");
+      n_written = app_send_stream_raw (tx_fifo,
+				       esm->vpp_queue[thread_index],
+				       esm->rx_buf[thread_index],
+				       actual_transfer, 0);
     }
+  else
+    {
+      n_written = app_send_dgram_raw (tx_fifo, &at,
+				      esm->vpp_queue[s->thread_index],
+				      esm->rx_buf[thread_index],
+				      actual_transfer, 0);
+    }
+
+  if (n_written != max_transfer)
+    clib_warning ("short trout! written %u read %u", n_written, max_transfer);
 
-  if (PREDICT_FALSE (n_written < max_dequeue))
+  if (PREDICT_FALSE (svm_fifo_max_dequeue (rx_fifo)))
     goto rx_event;
 
   return 0;
@@ -411,6 +428,7 @@ echo_server_create_command_fn (vlib_main_t * vm, unformat_input_t * input,
   esm->private_segment_count = 0;
   esm->private_segment_size = 0;
   esm->tls_engine = TLS_ENGINE_OPENSSL;
+  esm->is_dgram = 0;
   vec_free (esm->server_uri);
 
   while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
@@ -479,6 +497,8 @@ echo_server_create_command_fn (vlib_main_t * vm, unformat_input_t * input,
       clib_warning ("No uri provided! Using default: %s", default_uri);
       esm->server_uri = (char *) format (0, "%s%c", default_uri, 0);
     }
+  if (esm->server_uri[0] == 'u' && esm->server_uri[3] != 'c')
+    esm->is_dgram = 1;
 
   rv = echo_server_create (vm, appns_id, appns_flags, appns_secret);
   vec_free (appns_id);