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, 157 insertions, 0 deletions

diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index 5dc237f6e7b..5fd218533dc 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -173,6 +173,163 @@ extern const u32 test_srv_crt_rsa_len;
 extern const char test_srv_key_rsa[];
 extern const u32 test_srv_key_rsa_len;
 
+typedef struct app_session_transport_
+{
+  ip46_address_t rmt_ip;	/**< remote ip */
+  ip46_address_t lcl_ip;	/**< local ip */
+  u16 rmt_port;			/**< remote port */
+  u16 lcl_port;			/**< local port */
+  u8 is_ip4;			/**< set if uses ip4 networking */
+} app_session_transport_t;
+
+typedef struct app_session_
+{
+  svm_fifo_t *rx_fifo;			/**< rx fifo */
+  svm_fifo_t *tx_fifo;			/**< tx fifo */
+  session_type_t session_type;		/**< session type */
+  volatile u8 session_state;		/**< session state */
+  u32 session_index;			/**< index in owning pool */
+  app_session_transport_t transport;	/**< transport info */
+  svm_queue_t *vpp_evt_q;		/**< vpp event queue for session */
+  u8 is_dgram;				/**< set if it works in dgram mode */
+} app_session_t;
+
+always_inline int
+app_send_dgram_raw (svm_fifo_t * f, app_session_transport_t * at,
+		    svm_queue_t * vpp_evt_q, u8 * data, u32 len, u8 noblock)
+{
+  u32 max_enqueue, actual_write;
+  session_dgram_hdr_t hdr;
+  session_fifo_event_t evt;
+  int rv;
+
+  max_enqueue = svm_fifo_max_enqueue (f);
+  if (svm_fifo_max_enqueue (f) <= sizeof (session_dgram_hdr_t))
+    return 0;
+
+  max_enqueue -= sizeof (session_dgram_hdr_t);
+  actual_write = clib_min (len, max_enqueue);
+  hdr.data_length = actual_write;
+  hdr.data_offset = 0;
+  clib_memcpy (&hdr.rmt_ip, &at->rmt_ip, sizeof (ip46_address_t));
+  hdr.is_ip4 = at->is_ip4;
+  hdr.rmt_port = at->rmt_port;
+  clib_memcpy (&hdr.lcl_ip, &at->lcl_ip, sizeof (ip46_address_t));
+  hdr.lcl_port = at->lcl_port;
+  rv = svm_fifo_enqueue_nowait (f, sizeof (hdr), (u8 *) & hdr);
+  if (rv <= 0)
+    return 0;
+
+  ASSERT (rv == sizeof (hdr));
+
+  if ((rv = svm_fifo_enqueue_nowait (f, actual_write, data)) > 0)
+    {
+      if (svm_fifo_set_event (f))
+	{
+	  evt.fifo = f;
+	  evt.event_type = FIFO_EVENT_APP_TX;
+	  svm_queue_add (vpp_evt_q, (u8 *) & evt, noblock);
+	}
+    }
+  return rv;
+}
+
+always_inline int
+app_send_dgram (app_session_t * s, u8 * data, u32 len, u8 noblock)
+{
+  return app_send_dgram_raw (s->tx_fifo, &s->transport, s->vpp_evt_q, data,
+			     len, noblock);
+}
+
+always_inline int
+app_send_stream_raw (svm_fifo_t * f, svm_queue_t * vpp_evt_q, u8 * data,
+		     u32 len, u8 noblock)
+{
+  session_fifo_event_t evt;
+  int rv;
+
+  if ((rv = svm_fifo_enqueue_nowait (f, len, data)) > 0)
+    {
+      if (svm_fifo_set_event (f))
+	{
+	  evt.fifo = f;
+	  evt.event_type = FIFO_EVENT_APP_TX;
+	  svm_queue_add (vpp_evt_q, (u8 *) & evt, noblock);
+	}
+    }
+  return rv;
+}
+
+always_inline int
+app_send_stream (app_session_t * s, u8 * data, u32 len, u8 noblock)
+{
+  return app_send_stream_raw (s->tx_fifo, s->vpp_evt_q, data, len, noblock);
+}
+
+always_inline int
+app_send (app_session_t * s, u8 * data, u32 len, u8 noblock)
+{
+  if (s->is_dgram)
+    return app_send_dgram (s, data, len, noblock);
+  return app_send_stream (s, data, len, noblock);
+}
+
+always_inline int
+app_recv_dgram_raw (svm_fifo_t * f, u8 * buf, u32 len,
+		    app_session_transport_t * at, u8 clear_evt)
+{
+  session_dgram_pre_hdr_t ph;
+  u32 max_deq;
+  int rv;
+
+  if (clear_evt)
+    svm_fifo_unset_event (f);
+  max_deq = svm_fifo_max_dequeue (f);
+  if (max_deq < sizeof (session_dgram_hdr_t))
+    return 0;
+
+  svm_fifo_peek (f, 0, sizeof (ph), (u8 *) & ph);
+  ASSERT (ph.data_length >= ph.data_offset);
+  if (!ph.data_offset)
+    svm_fifo_peek (f, sizeof (ph), sizeof (*at), (u8 *) at);
+  len = clib_min (len, ph.data_length - ph.data_offset);
+  rv = svm_fifo_peek (f, ph.data_offset + SESSION_CONN_HDR_LEN, len, buf);
+  ph.data_offset += rv;
+  if (ph.data_offset == ph.data_length)
+    svm_fifo_dequeue_drop (f, ph.data_length + SESSION_CONN_HDR_LEN);
+  else
+    svm_fifo_overwrite_head (f, (u8 *) & ph, sizeof (ph));
+  return rv;
+}
+
+always_inline int
+app_recv_dgram (app_session_t * s, u8 * buf, u32 len)
+{
+  return app_recv_dgram_raw (s->rx_fifo, buf, len, &s->transport, 1);
+}
+
+always_inline int
+app_recv_stream_raw (svm_fifo_t * f, u8 * buf, u32 len, u8 clear_evt)
+{
+  if (clear_evt)
+    svm_fifo_unset_event (f);
+  return svm_fifo_dequeue_nowait (f, len, buf);
+}
+
+always_inline int
+app_recv_stream (app_session_t * s, u8 * buf, u32 len)
+{
+  return app_recv_stream_raw (s->rx_fifo, buf, len, 1);
+}
+
+always_inline int
+app_recv (app_session_t * s, u8 * data, u32 len)
+{
+  if (s->is_dgram)
+    return app_recv_dgram (s, data, len);
+  return app_recv_stream (s, data, len);
+}
+
 #endif /* __included_uri_h__ */
 
 /*