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>

3 files changed, 132 insertions, 95 deletions

diff --git a/src/vnet/session-apps/echo_client.c b/src/vnet/session-apps/echo_client.c
index 2cfb471413c..11528ef1899 100644
--- a/src/vnet/session-apps/echo_client.c
+++ b/src/vnet/session-apps/echo_client.c
@@ -46,23 +46,21 @@ static void
 send_data_chunk (echo_client_main_t * ecm, session_t * s)
 {
   u8 *test_data = ecm->connect_test_data;
-  int test_buf_offset;
+  int test_buf_len, test_buf_offset, rv;
   u32 bytes_this_chunk;
-  session_fifo_event_t evt;
-  svm_fifo_t *txf;
-  int rv;
 
   ASSERT (vec_len (test_data) > 0);
-
-  test_buf_offset = s->bytes_sent % vec_len (test_data);
-  bytes_this_chunk = vec_len (test_data) - test_buf_offset;
-
-  bytes_this_chunk = bytes_this_chunk < s->bytes_to_send
-    ? bytes_this_chunk : s->bytes_to_send;
-
-  txf = s->server_tx_fifo;
-  rv = svm_fifo_enqueue_nowait (txf, bytes_this_chunk,
-				test_data + test_buf_offset);
+  test_buf_len = vec_len (test_data);
+  test_buf_offset = s->bytes_sent % test_buf_len;
+  bytes_this_chunk = clib_min (test_buf_len - test_buf_offset,
+			       s->bytes_to_send);
+
+  if (!ecm->is_dgram)
+    rv = app_send_stream (&s->data, test_data + test_buf_offset,
+			  bytes_this_chunk, 0);
+  else
+    rv = app_send_dgram (&s->data, test_data + test_buf_offset,
+			 bytes_this_chunk, 0);
 
   /* If we managed to enqueue data... */
   if (rv > 0)
@@ -89,35 +87,24 @@ send_data_chunk (echo_client_main_t * ecm, session_t * s)
 	  ed->data[1] = s->bytes_sent;
 	  ed->data[2] = s->bytes_to_send;
 	}
-
-      /* Poke the session layer */
-      if (svm_fifo_set_event (txf))
-	{
-	  /* Fabricate TX event, send to vpp */
-	  evt.fifo = txf;
-	  evt.event_type = FIFO_EVENT_APP_TX;
-
-	  if (svm_queue_add
-	      (ecm->vpp_event_queue[txf->master_thread_index], (u8 *) & evt,
-	       0 /* do wait for mutex */ ))
-	    clib_warning ("could not enqueue event");
-	}
     }
 }
 
 static void
 receive_data_chunk (echo_client_main_t * ecm, session_t * s)
 {
-  svm_fifo_t *rx_fifo = s->server_rx_fifo;
-  u32 my_thread_index = vlib_get_thread_index ();
+  svm_fifo_t *rx_fifo = s->data.rx_fifo;
+  u32 thread_index = vlib_get_thread_index ();
   int n_read, i;
 
   if (ecm->test_bytes)
     {
-      n_read = svm_fifo_dequeue_nowait (rx_fifo,
-					vec_len (ecm->rx_buf
-						 [my_thread_index]),
-					ecm->rx_buf[my_thread_index]);
+      if (!ecm->is_dgram)
+	n_read = app_recv_stream (&s->data, ecm->rx_buf[thread_index],
+				  vec_len (ecm->rx_buf[thread_index]));
+      else
+	n_read = app_recv_dgram (&s->data, ecm->rx_buf[thread_index],
+				 vec_len (ecm->rx_buf[thread_index]));
     }
   else
     {
@@ -148,17 +135,18 @@ receive_data_chunk (echo_client_main_t * ecm, session_t * s)
 	{
 	  for (i = 0; i < n_read; i++)
 	    {
-	      if (ecm->rx_buf[my_thread_index][i]
+	      if (ecm->rx_buf[thread_index][i]
 		  != ((s->bytes_received + i) & 0xff))
 		{
 		  clib_warning ("read %d error at byte %lld, 0x%x not 0x%x",
 				n_read, s->bytes_received + i,
-				ecm->rx_buf[my_thread_index][i],
+				ecm->rx_buf[thread_index][i],
 				((s->bytes_received + i) & 0xff));
 		  ecm->test_failed = 1;
 		}
 	    }
 	}
+      ASSERT (n_read <= s->bytes_to_receive);
       s->bytes_to_receive -= n_read;
       s->bytes_received += n_read;
     }
@@ -230,20 +218,15 @@ echo_client_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 	}
       if (sp->bytes_to_receive > 0)
 	{
-	  receive_data_chunk (ecm, sp);
 	  delete_session = 0;
 	}
       if (PREDICT_FALSE (delete_session == 1))
 	{
-	  u32 index, thread_index;
 	  stream_session_t *s;
 
 	  __sync_fetch_and_add (&ecm->tx_total, sp->bytes_sent);
 	  __sync_fetch_and_add (&ecm->rx_total, sp->bytes_received);
-
-	  session_parse_handle (sp->vpp_session_handle,
-				&index, &thread_index);
-	  s = session_get_if_valid (index, thread_index);
+	  s = session_get_from_handle_if_valid (sp->vpp_session_handle);
 
 	  if (s)
 	    {
@@ -312,8 +295,8 @@ echo_clients_init (vlib_main_t * vm)
 
   num_threads = 1 /* main thread */  + vtm->n_threads;
 
-  /* Init test data. Bigecmuffer */
-  vec_validate (ecm->connect_test_data, 1024 * 1024 - 1);
+  /* Init test data. Big buffer */
+  vec_validate (ecm->connect_test_data, 4 * 1024 * 1024 - 1);
   for (i = 0; i < vec_len (ecm->connect_test_data); i++)
     ecm->connect_test_data[i] = i & 0xff;
 
@@ -363,12 +346,22 @@ echo_clients_session_connected_callback (u32 app_index, u32 api_context,
   session_index = session - ecm->sessions;
   session->bytes_to_send = ecm->bytes_to_send;
   session->bytes_to_receive = ecm->no_return ? 0ULL : ecm->bytes_to_send;
-  session->server_rx_fifo = s->server_rx_fifo;
-  session->server_rx_fifo->client_session_index = session_index;
-  session->server_tx_fifo = s->server_tx_fifo;
-  session->server_tx_fifo->client_session_index = session_index;
+  session->data.rx_fifo = s->server_rx_fifo;
+  session->data.rx_fifo->client_session_index = session_index;
+  session->data.tx_fifo = s->server_tx_fifo;
+  session->data.tx_fifo->client_session_index = session_index;
+  session->data.vpp_evt_q = ecm->vpp_event_queue[thread_index];
   session->vpp_session_handle = session_handle (s);
 
+  if (ecm->is_dgram)
+    {
+      transport_connection_t *tc;
+      tc = session_get_transport (s);
+      clib_memcpy (&session->data.transport, tc,
+		   sizeof (session->data.transport));
+      session->data.is_dgram = 1;
+    }
+
   vec_add1 (ecm->connection_index_by_thread[thread_index], session_index);
   __sync_fetch_and_add (&ecm->ready_connections, 1);
   if (ecm->ready_connections == ecm->expected_connections)
@@ -410,6 +403,28 @@ echo_clients_session_disconnect_callback (stream_session_t * s)
 static int
 echo_clients_rx_callback (stream_session_t * s)
 {
+  echo_client_main_t *ecm = &echo_client_main;
+  session_t *sp;
+
+  sp = pool_elt_at_index (ecm->sessions,
+			  s->server_rx_fifo->client_session_index);
+  receive_data_chunk (ecm, sp);
+
+  if (svm_fifo_max_dequeue (s->server_rx_fifo))
+    {
+      session_fifo_event_t evt;
+      svm_queue_t *q;
+      if (svm_fifo_set_event (s->server_rx_fifo))
+	{
+	  evt.fifo = s->server_rx_fifo;
+	  evt.event_type = FIFO_EVENT_BUILTIN_RX;
+	  q = session_manager_get_vpp_event_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");
+	}
+    }
   return 0;
 }
 
@@ -544,7 +559,7 @@ echo_clients_connect (vlib_main_t * vm, u32 n_clients)
 }
 
 #define ec_cli_output(_fmt, _args...) 			\
-  if (!ecm->no_output)  					\
+  if (!ecm->no_output)  				\
     vlib_cli_output(vm, _fmt, ##_args)
 
 static clib_error_t *
@@ -663,6 +678,9 @@ echo_clients_command_fn (vlib_main_t * vm,
       ecm->connect_uri = format (0, "%s%c", default_uri, 0);
     }
 
+  if (ecm->connect_uri[0] == 'u' && ecm->connect_uri[3] != 'c')
+    ecm->is_dgram = 1;
+
 #if ECHO_CLIENT_PTHREAD
   echo_clients_start_tx_pthread ();
 #endif
diff --git a/src/vnet/session-apps/echo_client.h b/src/vnet/session-apps/echo_client.h
index 5712da5b8c8..344e43865b5 100644
--- a/src/vnet/session-apps/echo_client.h
+++ b/src/vnet/session-apps/echo_client.h
@@ -30,15 +30,13 @@
 
 typedef struct
 {
+  app_session_t data;
   u64 bytes_to_send;
   u64 bytes_sent;
   u64 bytes_to_receive;
   u64 bytes_received;
-
-  svm_fifo_t *server_rx_fifo;
-  svm_fifo_t *server_tx_fifo;
-
   u64 vpp_session_handle;
+  u8 thread_index;
 } session_t;
 
 typedef struct
@@ -46,7 +44,7 @@ typedef struct
   /*
    * Application setup parameters
    */
-  svm_queue_t *vl_input_queue;	/**< vpe input queue */
+  svm_queue_t *vl_input_queue;		/**< vpe input queue */
   svm_queue_t **vpp_event_queue;
 
   u32 cli_node_index;			/**< cli process node index */
@@ -65,6 +63,7 @@ typedef struct
   u32 private_segment_count;		/**< Number of private fifo segs */
   u32 private_segment_size;		/**< size of private fifo segs */
   u32 tls_engine;			/**< TLS engine mbedtls/openssl */
+  u8 is_dgram;
   /*
    * Test state variables
    */
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);